# kb

id: regression-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Regression_(medicine)-0.md
category: reference
title: Regression (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Regression_(medicine)
date_saved: 2026-05-05T07:32:31.331934+00:00
instance: kb-cron
parent: regression-medicine-20260505-0
summary:
Regression in medicine is the partial or complete reversal of a disease's signs and symptoms. Clinically, regression generally refers to a decrease in severity of symptoms without completely disappearing. At a later point, symptoms may return. These symptoms are then called recidive. In cancer, regression refers to a specific decrease in the size or extent of a tumour. In histopathology, histological regression is one or more areas within a tumor in which neoplastic cells have disappeared or decreased in number. In melanomas, this means complete or partial disappearance from areas of the dermis (and occasionally from the epidermis), which have been replaced by fibrosis, accompanied by melanophages, new blood vessels, and a variable degree of inflammation. == References ==


id: relapsing-remitting-20260505-0
file: data/en.wikipedia.org/wiki/Relapsing–remitting-0.md
category: reference
title: Relapsing–remitting
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Relapsing–remitting
date_saved: 2026-05-05T07:32:32.477854+00:00
instance: kb-cron
parent: relapsing-remitting-20260505-0
summary:
Relapsing–remitting is a medical term referring to a presentation of disease symptoms that become worse over time (relapsing), followed by periods of less severe symptoms that do not completely cease (partial remitting). The term is used to describe a type of multiple sclerosis called relapsing–remitting multiple sclerosis, where unpredictable relapses are followed by remission for months to years. The term is also used to describe palindromic rheumatism in the context of rheumatoid arthritis, catatonia, lupus, mental disorders, and experimental autoimmune encephalomyelitis. == References ==


id: remission-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Remission_(medicine)-0.md
category: reference
title: Remission (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Remission_(medicine)
date_saved: 2026-05-05T07:32:33.706636+00:00
instance: kb-cron
parent: remission-medicine-20260505-0
summary:
Remission is either the reduction or disappearance of the signs and symptoms of a disease. The term may also be used to refer to the period during which this reduction occurs. A remission may be considered a partial remission or a complete remission. Each disease, type of disorder, or clinical trial can have its own definition of a partial remission. For example, a partial remission for cancer may be defined as a 50% or greater reduction in the measurable parameters of tumor growth as may be found on physical examination, radiologic study, or by biomarker levels from a blood or urine test. A complete remission, also called a full remission, is a total disappearance of the signs and symptoms of a disease. A person whose condition is in complete remission may be considered cured or recovered. Relapse is a term to describe returning symptoms of the disease after a period of remission. In cancer-treatment, doctors usually avoid the term "cured" and instead prefer the term "no evidence of disease" (NED) to refer to a complete remission of cancer, which does not rule out the possibility of relapse. In mental disorders, there is generally no distinction between partial remission and complete


id: responsible-drug-use-20260505-0
file: data/en.wikipedia.org/wiki/Responsible_drug_use-0.md
category: reference
title: Responsible drug use
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Responsible_drug_use
date_saved: 2026-05-05T07:32:34.912036+00:00
instance: kb-cron
parent: responsible-drug-use-20260505-0
summary:
Responsible drug use seeks to maximize the benefits and minimize the risks associated with psychoactive drug use. For illegal psychoactive drugs that are not diverted prescription controlled substances, some critics believe that illegal recreational drug use is inherently irresponsible, due to the unpredictable and unmonitored strength and purity of the drugs and the risks of addiction, infection, and other side effects. Nevertheless, harm reduction advocates claim that the user can be responsible by employing the same general principles applicable to the use of alcohol: avoiding hazardous situations, excessive doses, and hazardous combinations of drugs; avoiding injection; and not using drugs at the same time as activities that may be unsafe without a sober state. Drug use can be thought of as an activity that is potentially beneficial but also potentially risky. Similar to other risky activities such as skydiving or mountain climbing, the varied risks of drug use can be minimized by using harm-reduction strategies such as education, caution, and common sense. These advocates also point out that government action (or inaction) makes responsible drug use more difficult by artificially increasing risks, such as by making drugs of known purity and strength unavailable due to prohibition. == Harm reduction ==


id: responsible-drug-use-20260505-1
file: data/en.wikipedia.org/wiki/Responsible_drug_use-1.md
category: reference
title: Responsible drug use
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Responsible_drug_use
date_saved: 2026-05-05T07:32:34.912036+00:00
instance: kb-cron
parent: responsible-drug-use-20260505-0
summary:
understanding and educating oneself on the effects, risks, side effects and legal status of the drug they are taking measuring accurate dosages, and take other precautions to reduce the risk of overdose when taking drugs where an overdose is possible if possible, drug checking all substances before use to determine their purity and strength attempting to gain the most pure and high-quality drugs, laced with no cutting agent at best such as by buying on darknet markets using drugs only in relaxed and responsible social situations as altered consciousness can be inappropriate in potentially dangerous or unknown settings avoiding driving, operating heavy machinery, or otherwise situate themselves directly or indirectly responsible for the safety or care of another person while intoxicated and discouraging persons from operating a motor vehicle while intoxicated having a trip sitter (or "copilot") when taking hallucinogenic drugs taking a small dose first when taking a new drug ("start low and go slow") taking the smallest dose of a recreational drug that will produce the desired effects using recreational drugs in moderation, setting reasonable limits on the consumption and not allowing drug use to overshadow other aspects of their life (i.e. financial and social responsibilities) avoiding mixing


id: responsible-drug-use-20260505-2
file: data/en.wikipedia.org/wiki/Responsible_drug_use-2.md
category: reference
title: Responsible drug use
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Responsible_drug_use
date_saved: 2026-05-05T07:32:34.912036+00:00
instance: kb-cron
parent: responsible-drug-use-20260505-0
summary:
== Organizations == Many organizations exist to promote responsible drug use and harm reduction throughout the world. Some, such as Students for Sensible Drug Policy or Drug Policy Alliance, are primarily activist groups concerned with drug policy reform, promoting scientific research on drugs, and opposing stigma and misinformation about drug use and drug users. Others exist primarily as drug testing services for drug users (e.g. Energy Control or DrugsData), or as supervised injection services (e.g. Insite), or as informational sources (e.g. Bluelight or Erowid). Governments have begun to address responsible drug use within their respective jurisdictions. The U.S. Department of Health and Human Services addresses harm reduction through the Substance Abuse and Mental Health Services Administration as a part of the department's Overdose Prevention Strategy. == See also == == References == == Further reading == Zinberg, N. E. (1984) Drug, Set, And Setting: The Basis for Controlled Intoxicant Use (New Haven: Yale University Press) ISBN 0-300-03110-6 == External links == Fact sheets on responsible recreational drug use Towards a Culture of Responsible Psychoactive Drug Use Fundamentals of Responsible Psychoactive Use, Erowid === Harm reduction === The History of Harm Reduction SOM.NIT // Risk reduction associated with recreational drug consumption


id: review-of-systems-20260505-0
file: data/en.wikipedia.org/wiki/Review_of_systems-0.md
category: reference
title: Review of systems
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Review_of_systems
date_saved: 2026-05-05T07:32:36.064738+00:00
instance: kb-cron
parent: review-of-systems-20260505-0
summary:
A review of systems (ROS), also called a systems enquiry or systems review, is a technique used by healthcare providers for eliciting a medical history from a patient. It is often structured as a component of an admission note covering the organ systems, with a focus upon the subjective symptoms perceived by the patient (as opposed to the objective signs perceived by the clinician). Along with the physical examination, it can be particularly useful in identifying conditions that do not have precise diagnostic tests. == Examples == Whatever system a specific condition may seem restricted to, it may be reasonable to review all the other systems in a comprehensive history. Different sources describe slightly different systems of organizing the organ systems. However, the following are examples of what can be included. Unspecified and other symptoms can't consider for both HPI and ROS: There are 14 systems recognized by the Centers for Medicare and Medicaid Services: The questions may be asked of the patient in a "head to toe" manner. == Relationship to history == For CMS, a "problem pertinent" ROS is limited to the problem(s) identified in the HPI; an "extended" ROS covers an additional 2 to 9 systems, and


id: right-atrial-pressure-20260505-0
file: data/en.wikipedia.org/wiki/Right_atrial_pressure-0.md
category: reference
title: Right atrial pressure
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Right_atrial_pressure
date_saved: 2026-05-05T07:32:37.358360+00:00
instance: kb-cron
parent: right-atrial-pressure-20260505-0
summary:
Right atrial pressure (RAP) is the blood pressure in the right atrium of the heart. RAP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system. RAP is often nearly identical to central venous pressure (CVP), although the two terms are not identical, as a pressure differential can sometimes exist between the venae cavae and the right atrium. CVP and RAP can differ when venous tone (i.e the degree of venous constriction) is altered. This can be graphically depicted as changes in the slope of the venous return (VR) plotted against right atrial pressure (where central venous pressure (CVP) increases, but right atrial pressure (RAP) stays the same; VR = CVP − RAP). == Factors affecting RAP == Factors that increase RAP include: Hypervolemia Forced exhalation Tension pneumothorax Heart failure Pleural effusion Decreased cardiac output Cardiac tamponade Mechanical ventilation and the application of positive end-expiratory pressure (PEEP) Pulmonary Hypertension Pulmonary Embolism Left to right shunted Atrial Septal Defect Factors that decrease RAP include: Hypovolemia Deep inhalation Distributive shock == See also == Pulmonary capillary wedge pressure Jugular venous pressure Central venous pressure == References == == External


id: right-to-left-shunt-20260505-0
file: data/en.wikipedia.org/wiki/Right-to-left_shunt-0.md
category: reference
title: Right-to-left shunt
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Right-to-left_shunt
date_saved: 2026-05-05T07:32:38.670025+00:00
instance: kb-cron
parent: right-to-left-shunt-20260505-0
summary:
A right-to-left shunt is a cardiac shunt which allows blood to flow from the right heart to the left heart. This terminology is used both for the abnormal state in humans and for normal physiological shunts in reptiles. == Clinical Significance == A right-to-left shunt occurs when: there is an opening or passage between the atria, ventricles, and/or great vessels; and, right heart pressure is higher than left heart pressure and/or the shunt has a one-way valvular opening. Small physiological, or "normal", shunts are seen due to the return of bronchial artery blood and coronary blood through the Thebesian veins, which are deoxygenated, to the left side of the heart. === Causes === Congenital defects can lead to right-to-left shunting immediately after birth: Persistent truncus arteriosus (minimal cyanosis) Transposition of great vessels Tricuspid atresia Tetralogy of Fallot Total anomalous pulmonary venous return A mnemonic to remember the conditions associated with right-to-left shunting involves the numbers 1-5, as follows: 1 Combination Vessel: Persistent truncus arteriosus (minimal cyanosis) 2 Vessels involved: Transposition of great vessels 3 Leaflets: Tricuspid atresia 4 Tetra- prefix: Tetralogy of Fallot 5 Words: Total anomalous pulmonary venous return A mainstem intubation with an endotracheal tube can lead to


id: risk-of-infection-20260505-0
file: data/en.wikipedia.org/wiki/Risk_of_infection-0.md
category: reference
title: Risk of infection
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Risk_of_infection
date_saved: 2026-05-05T07:32:39.833246+00:00
instance: kb-cron
parent: risk-of-infection-20260505-0
summary:
Risk of infection is a nursing diagnosis which is defined as the state in which an individual is at risk to be infected by an opportunistic or pathogenic agent (e.g., viruses, fungi, bacteria, protozoa, or other parasites) from endogenous or exogenous sources. The diagnosis was approved by NANDA in 1986. Although anyone can become infected by a pathogen, patients with this diagnosis are at an elevated risk and extra infection controls should be considered. == Endogenous sources == The risk of infection depends on a number of endogenous sources. Chronic blood loss leads to iron and nutrient deficiencies essential for immune cell production and function, thereby decreasing the body’s resistance to infection and placing the patient at increased risk for infection. == Assessment == The patient should be asked about a history of repeated infections, symptoms of infection, recent travel to high-risk areas, and their immunization history. They should also be assessed for objective signs such as the presence of wounds, fever, or signs of nutritional deficiency == Intervention == The specific nursing interventions will depend on the nature and severity of the risk. Patients should be taught how to recognize the signs of infection and how to reduce their


id: risk-of-mortality-20260505-0
file: data/en.wikipedia.org/wiki/Risk_of_mortality-0.md
category: reference
title: Risk of mortality
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Risk_of_mortality
date_saved: 2026-05-05T07:32:41.068791+00:00
instance: kb-cron
parent: risk-of-mortality-20260505-0
summary:
The risk of mortality (ROM) provides a medical classification to estimate the likelihood of in-hospital death for a patient. The ROM classes are minor, moderate, major, and extreme. The ROM class is used for the evaluation of patient mortality. == See also == Case mix index Diagnosis codes Severity of illness == References == Alemi, F., J. Rice, and R. Hankins. 1990. "Predicting In-Hospital Survival of Myocardial Infarction." Medical Care 28 (9): 762–75. Averill, R. F., J. H. Muldoon, J. C. Vertrees, N. I. Goldfield, R. L. Mullin, E. C. Fineran, M. Z. Zhang, B. Steinbeck, and T. Grant, The Evolution of Casemix Measurement Using Diagnosis Related Groups (DRGs) 3M HIS Working Paper. Wallinford, CT: 3M Health Information Systems, 1997 Iezzoni, L. I., M. Shwartz, A. S. Ash, J. S. Hughes, J. Daley, and Y. D. Mackiernan, Severity Measurement Methods and Judging Hospital Death Rates for Pneumonia, Medical Care 34 (1): 11–28, 1996


id: risky-sexual-behavior-20260505-0
file: data/en.wikipedia.org/wiki/Risky_sexual_behavior-0.md
category: reference
title: Risky sexual behavior
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Risky_sexual_behavior
date_saved: 2026-05-05T07:32:42.273338+00:00
instance: kb-cron
parent: risky-sexual-behavior-20260505-0
summary:
Risky sexual behavior is the description of the activity that will increase the probability that a person engaging in sexual activity with another person infected with a sexually transmitted infection will be infected, become unintentionally pregnant, or make a partner pregnant. It can mean two similar things: the behavior itself, and the description of the partner's behavior. The behavior could be unprotected vaginal, oral, anal, or non-penetrative manual intercourse. The partner could be a non-exclusive sexual partner, HIV-positive, and/or an intravenous drug user. == Factors == Risky sexual behaviors can include: Sex and drugs such as alcohol or methamphetamine. Barebacking, i.e. sex without using condoms. Mouth-to-genital contact. Starting sexual activity at a young age. Having multiple sexual partners. Having a high-risk partner, someone who has multiple sexual partners and/or infections. Anal sex without using condoms and proper lubrication. Sex with a partner who has ever injected drugs. Engaging in sex work. Consumption of pornographic materials (which can encourage other risky sexual behaviors) Risky sexual behavior includes unprotected intercourse, multiple sexual partners, and illicit drug use. The use of alcoholic drinks and illicit drugs greatly increases the risk of gonorrhea, chlamydia, trichomoniasis, hepatitis B, and HIV/AIDS. Trauma from penile-anal sex has


id: sari-screening-tool-20260505-0
file: data/en.wikipedia.org/wiki/SARI_Screening_Tool-0.md
category: reference
title: SARI Screening Tool
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SARI_Screening_Tool
date_saved: 2026-05-05T07:32:43.480584+00:00
instance: kb-cron
parent: sari-screening-tool-20260505-0
summary:
SARI Screening Tool also known as the SARI score is a tool developed by the Ministry of Health in the Kingdom of Saudi Arabia. It is a visual triage used to identify those with the potential to have COVID-19. The tools was also used to screen for MERS. It has been modified multiple times and the weights of each symptom have been changed over time as well. == References ==


id: sclerosis-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Sclerosis_(medicine)-0.md
category: reference
title: Sclerosis (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sclerosis_(medicine)
date_saved: 2026-05-05T07:32:44.831503+00:00
instance: kb-cron
parent: sclerosis-medicine-20260505-0
summary:
Sclerosis (from Ancient Greek σκληρός (sklērós) 'hard') is the stiffening of a tissue or anatomical feature, usually caused by a replacement of the normal organ-specific tissue with connective tissue. The structure may be said to have undergone sclerotic changes or display sclerotic lesions, which refers to the process of sclerosis. Common medical conditions whose pathology involves sclerosis include: Amyotrophic lateral sclerosis—also known as Lou Gehrig's disease or motor neurone disease—a progressive, incurable, usually fatal disease of motor neurons. Atherosclerosis, a deposit of fatty materials, such as cholesterol, in the arteries which causes hardening. Focal segmental glomerulosclerosis is a disease that attacks the kidney's filtering system (glomeruli) causing serious scarring and thus a cause of nephrotic syndrome in children and adolescents, as well as an important cause of kidney failure in adults. Hippocampal sclerosis, a brain damage often seen in individuals with temporal lobe epilepsy. Lichen sclerosus, an inflammatory skin disease that most often affects the vulva and the penis. Multiple sclerosis, or focal sclerosis, is a central nervous system disease which affects coordination. Osteosclerosis, a condition where the bone density is significantly increased, resulting in decreased lucency on radiographs. Otosclerosis, a disease of the ears. Primary lateral sclerosis, progressive muscle


id: screen-time-20260505-0
file: data/en.wikipedia.org/wiki/Screen_time-0.md
category: reference
title: Screen time
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Screen_time
date_saved: 2026-05-05T07:32:46.015001+00:00
instance: kb-cron
parent: screen-time-20260505-0
summary:
Screen time is the amount of time spent using an electronic device with a display screen such as a smartphone, computer, television, video game console, or tablet. The concept is under significant research with related concepts in digital media use and mental health. Screen time is correlated with mental and physical harm in child development. The positive or negative health effects of screen time on a particular individual are influenced by levels and content of exposure. Screen time increases dopamine. To prevent harmful excesses of screen time, some governments have placed regulations on usage. == History == === Statistics === The first electronic screen was the cathode ray tube (CRT), which was invented in 1922. CRTs were the most popular choice for display screens until the rise of liquid crystal displays (LCDs) in the early 2000s. Screens are now an essential part of entertainment, advertising, and information technologies. Since their popularization in 2007, smartphones have become ubiquitous in daily life. In 2023, 85% of American adults reported owning a smartphone. An American survey in 2016 found a median of 3.7 minutes per hour screen use per citizen. All forms of screens are frequently used by children and teens. Nationally representative


id: screen-time-20260505-1
file: data/en.wikipedia.org/wiki/Screen_time-1.md
category: reference
title: Screen time
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Screen_time
date_saved: 2026-05-05T07:32:46.015001+00:00
instance: kb-cron
parent: screen-time-20260505-0
summary:
Increased use of screens in children has also been shown to have an association with adverse effects on the quality of sleep in children. A 2010 review concluded that "the use of electronic media by children and adolescents does have a negative impact on their sleep, although the precise effects and mechanisms remain unclear", with the most consistent results associating excessive media use with shorter sleep duration and delayed bed times. A 2016 meta-analysis found that "Bedtime access and use of media devices was significantly associated with inadequate sleep quantity; poor sleep quality; and excessive daytime sleepiness". This relationship is because much of the time spent on screens for children is at night, which can cause them to go to sleep later in addition to the blue light from the screens making it more difficult to sleep. However, the relationship between screen use and sleep may not be the same across neurotypical and neurodivergent children. There are reasons to believe that autistic children, for example, may be more interested in screens than their neurotypical peers, and less able to disengage from them. A 2025 systematic review found that a causal link between screen-time use and sleep in autistic children could


id: screen-time-20260505-2
file: data/en.wikipedia.org/wiki/Screen_time-2.md
category: reference
title: Screen time
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Screen_time
date_saved: 2026-05-05T07:32:46.015001+00:00
instance: kb-cron
parent: screen-time-20260505-0
summary:
=== Brain development === An increase in screen time has been associated with negative cognitive outcomes for children between 0 and 4. A study on Korean children aged 24–30 months old found that toddlers with 3 hours of TV viewing per day were three times as likely to experience a language delay. Toddlers with higher TV time also scored lower on school readiness tests, which measured vocabulary, number knowledge, and classroom engagement. The same outcomes are not present in children older than 4. Children who watched more TV were found to have less brain connectivity between language, visual and cognitive control regions of the brain than their peers who watched less TV. An ongoing study reported from the National Institutes of Health concluded that preteens who spent over 7 hours on screens a day and children who spend less than 7 hours a day had noticeably different development of their cerebral cortex. This part of the brain usually thins as people mature but the accelerated decrease could potentially be linked to amounts spent on screens. The American Academy of Pediatrics recommends a screen time no longer than 1 hour per day for children aged 3–5. According to a study published


id: screen-time-20260505-3
file: data/en.wikipedia.org/wiki/Screen_time-3.md
category: reference
title: Screen time
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Screen_time
date_saved: 2026-05-05T07:32:46.015001+00:00
instance: kb-cron
parent: screen-time-20260505-0
summary:
Research shows that children who lack guidance from their mothers are more likely to overuse screen time and also to struggle academically. Those with more prevalent maternal interference in their online activities tend to have more controlled screen time. These children also watched more educational content when online versus their counterparts with less parental control. Educational content consumed during time allotted for digital use is shown to be positively associated with academic achievement. On the other hand, those who only consumed violent media or leisurely video games on school nights, showed a negative associated with academic achievement. Their lower academic performances were marked by decreases in grade averages and in their ability to adjust to a school or academic environment. Inability to adjust to these situations resulted in a negative effect on school performance. == Environmental effects == More screen time generally leads to less time spent in nature and therefore a weaker connection to it. Studies show nature-inspired activities simultaneously decrease for youth in financially stabilized countries with mental health issues increasing, drawing a connection to higher screen time levels. However, the higher the count in activities spent experiencing the outdoors produced positive results in mental health among adolescents.


id: screening-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Screening_(medicine)-0.md
category: reference
title: Screening (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Screening_(medicine)
date_saved: 2026-05-05T07:32:47.287610+00:00
instance: kb-cron
parent: screening-medicine-20260505-0
summary:
In medicine, screening is a strategy used to look for as-yet-unrecognised conditions or risk markers. This testing can be applied to individuals or to a whole population without symptoms or signs of the disease being screened. Screening interventions are designed to identify conditions which could at some future point turn into disease, thus enabling earlier intervention and management in the hope to reduce mortality and suffering from a disease. Although screening may lead to an earlier diagnosis, not all screening tests have been shown to benefit the person being screened- overdiagnosis, misdiagnosis, and creating a false sense of security are some potential adverse effects of screening. Additionally, some screening tests can be inappropriately overused. For these reasons, a test used in a screening program, especially for a disease with low incidence, must have good sensitivity in addition to acceptable specificity. Several types of screening exist: universal (population-based) screening involves testing of all individuals in a certain category (for example, all children of a certain age). Case finding involves testing a smaller group of people based on the presence of risk factors (for example, because a family member has been diagnosed with a hereditary disease). When delivered to large numbers of


id: screening-medicine-20260505-1
file: data/en.wikipedia.org/wiki/Screening_(medicine)-1.md
category: reference
title: Screening (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Screening_(medicine)
date_saved: 2026-05-05T07:32:47.287610+00:00
instance: kb-cron
parent: screening-medicine-20260505-0
summary:
=== Screening for social determinants of health === The social determinants of health are the economic and social conditions that influence individual and group differences in health status. Those conditions may have adverse effects on their health and well-being. To mitigate those adverse effects, certain health policies like the United States Affordable Care Act (2010) gave increased traction to preventive programs, such as those that routinely screen for social determinants of health. Screening is believed to a valuable tool in identifying patients' basic needs in a social determinants of health framework so that they can be better served. ==== Policy background in the United States ==== When established in the United States, the Affordable Care Act was able to bridge the gap between community-based health and healthcare as a medical treatment, leading to programs that screened for social determinants of health. The Affordable Care Act established several services with an eye for social determinants or an openness to more diverse clientele, such as Community Transformation Grants, which were delegated to the community in order to establish "preventive community health activities" and "address health disparities". ==== Clinical programs ==== Social determinants of health include social status, gender, ethnicity, economic status, education


id: screening-medicine-20260505-2
file: data/en.wikipedia.org/wiki/Screening_(medicine)-2.md
category: reference
title: Screening (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Screening_(medicine)
date_saved: 2026-05-05T07:32:47.287610+00:00
instance: kb-cron
parent: screening-medicine-20260505-0
summary:
Screening may identify abnormalities that would never cause a problem in a person's lifetime. An example of this is prostate cancer screening; it has been said that "more men die with prostate cancer than of it". Autopsy studies have shown that between 14 and 77% of elderly men who have died of other causes are found to have had prostate cancer. Aside from issues with unnecessary treatment (prostate cancer treatment is by no means without risk), overdiagnosis makes a study look good at picking up abnormalities, even though they are sometimes harmless. Overdiagnosis occurs when all of these people with harmless abnormalities are counted as "lives saved" by the screening, rather than as "healthy people needlessly harmed by overdiagnosis". So it might lead to an endless cycle: the greater the overdiagnosis, the more people will think screening is more effective than it is, which can reinforce people to do more screening tests, leading to even more overdiagnosis. Raffle, Mackie and Gray call this the popularity paradox of screening: "The greater the harm through overdiagnosis and overtreatment from screening, the more people there are who believe they owe their health, or even their life, to the programme"(p56 Box 3.4) The screening


id: screening-medicine-20260505-3
file: data/en.wikipedia.org/wiki/Screening_(medicine)-3.md
category: reference
title: Screening (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Screening_(medicine)
date_saved: 2026-05-05T07:32:47.287610+00:00
instance: kb-cron
parent: screening-medicine-20260505-0
summary:
Not everyone will partake in a screening program. There are factors that differ between those willing to get tested and those who are not. If people with a higher risk of a disease are more likely to be screened, for instance women with a family history of breast cancer are more likely than other women to join a mammography program, then a screening test will look worse than it really is: negative outcomes among the screened population will be higher than for a random sample. Selection bias may also make a test look better than it really is. If a test is more available to young and healthy people (for instance if people have to travel a long distance to get checked) then fewer people in the screening population will have negative outcomes than for a random sample, and the test will seem to make a positive difference. Studies have shown that people who attend screening tend to be healthier than those who do not. This has been called the healthy screenee effect, which is a form of selection bias. The reason seems to be that people who are healthy, affluent, physically fit, non-smokers with long-lived parents are more likely


id: secondary-malignant-neoplasm-20260505-0
file: data/en.wikipedia.org/wiki/Secondary_malignant_neoplasm-0.md
category: reference
title: Secondary malignant neoplasm
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Secondary_malignant_neoplasm
date_saved: 2026-05-05T07:32:48.442724+00:00
instance: kb-cron
parent: secondary-malignant-neoplasm-20260505-0
summary:
Secondary malignant neoplasm is a malignant tumor whose cause is the treatment (usually radiation or chemotherapy) which was used for a prior tumor. It must be distinguished from Metastasis from the prior tumor or a relapse from it since a secondary malignant neoplasm is a different tumor. == References ==


id: secretomotor-20260505-0
file: data/en.wikipedia.org/wiki/Secretomotor-0.md
category: reference
title: Secretomotor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Secretomotor
date_saved: 2026-05-05T07:32:49.703071+00:00
instance: kb-cron
parent: secretomotor-20260505-0
summary:
The adjective secretomotor refers to the capacity of a structure (often a nerve) to induce a gland to secrete a substance (usually mucus or serous fluid). Secretomotor nerve endings are frequently contrasted with sensory neuron endings and motor nerve endings. An example of secretomotor activity can be seen with the lacrimal gland, which secretes the aqueous layer of the tear film. The lacrimal branch of the ophthalmic nerve (itself a branch of trigeminal nerve V1) supplies secretomotor innervation to the lacrimal gland, stimulating its secretion of the aqueous layer. However, these nerves fibers originate from the facial nerve (VII) and only travel briefly with fibers from the trigeminal nerve. Secretomotor neurons in the intestines and gall bladder control the movement of fluid and electrolytes. == References ==


id: sedentary-lifestyle-20260505-0
file: data/en.wikipedia.org/wiki/Sedentary_lifestyle-0.md
category: reference
title: Sedentary lifestyle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sedentary_lifestyle
date_saved: 2026-05-05T07:32:51.056809+00:00
instance: kb-cron
parent: sedentary-lifestyle-20260505-0
summary:
Sedentary lifestyle is a lifestyle type, in which one is physically inactive and does little or no physical movement and/or exercise. A person living a sedentary lifestyle is often sitting or lying down while engaged in an activity like socializing, watching TV, playing video games, reading or using a mobile phone or computer for much of the day. A sedentary lifestyle contributes to poor health quality, diseases as well as many preventable causes of death. Sitting time is a common measure of a sedentary lifestyle. A global review representing 47% of the global adult population found that the average person sits down for 4.7 to 6.5 hours a day with the average going up every year. Screen time is a term for the amount of time a person spends looking at a screen such as a television, computer monitor, or mobile device. Excessive screen time is linked to negative health consequences. == Definition == Sedentary behavior is not the same as physical inactivity: sedentary behavior is defined as "any waking behavior characterized by an energy expenditure less than or equal to 1.5 metabolic equivalents (METs), while in a sitting, reclining or lying posture". Spending most waking hours sitting does not


id: sedentary-lifestyle-20260505-1
file: data/en.wikipedia.org/wiki/Sedentary_lifestyle-1.md
category: reference
title: Sedentary lifestyle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sedentary_lifestyle
date_saved: 2026-05-05T07:32:51.056809+00:00
instance: kb-cron
parent: sedentary-lifestyle-20260505-0
summary:
Adults and children spend long amounts of time sitting in a workplace or at a school, which is why interventions have been focused in these two areas. Mass media campaigns might also be able to reduce the amount of time spent sitting or lying down and positively affect the intention to be active physically. Recent innovations in AI technology have led to the development of exercise prescription systems designed to reduce sedentary behavior. These systems deliver personalized exercise plans by analyzing individual health metrics, potentially decreasing the prevalence of a sedentary lifestyle and its associated health risks. === In urban spaces === Some evidence has been found of a negative association between exposure to an existing urban motorway and moderate to vigorous physical activity. The proportion of physically active individuals was higher in high- versus low-walkability neighborhoods. Rising rates of being overweight, obesity, and physical inactivity in China's rapidly growing cities and urban populations have been due to urban development practices and policies. === In a work environment === Occupational sedentary behaviour accounts for a significant proportion of sitting time for many adults. Some workplaces have implemented exercise classes at lunch, walking challenges among coworkers, or allowing employees to stand


id: self-diagnosis-20260505-0
file: data/en.wikipedia.org/wiki/Self-diagnosis-0.md
category: reference
title: Self-diagnosis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Self-diagnosis
date_saved: 2026-05-05T07:32:52.335800+00:00
instance: kb-cron
parent: self-diagnosis-20260505-0
summary:
Self-diagnosis is the process of diagnosing, or identifying, medical conditions in oneself. It may be assisted by medical dictionaries, books, resources on the Internet, past personal experiences, or recognizing symptoms or medical signs of a condition that a family member previously had or currently has. Depending on the nature of an individual's condition and the accuracy of the information they access, self-diagnoses can vary greatly in their safety. Due to self-diagnoses' varied accuracy, public attitudes toward self-diagnosis include denials of its legitimacy and applause of its ability to promote healthcare access and allow for individuals to find solidarity and support. Furthermore, external influences such as marketing, social media trends, societal stigma around disease, and to which demographic population one belongs greatly affect the use of self-diagnosis. == Appropriate use == Self-diagnosis is prone to error and may be potentially dangerous if inappropriate decisions are made, which can stem from broad or inaccurately applied symptoms as well as confirmation bias. Because of the risks, self-diagnosis is officially discouraged by physicians and patient care organizations. Physicians are also discouraged from engaging in self-diagnosis due to potential lack of objectivity. An inaccurate self-diagnosis—a misdiagnosis—can result in improper health care, including using the wrong


id: self-diagnosis-20260505-1
file: data/en.wikipedia.org/wiki/Self-diagnosis-1.md
category: reference
title: Self-diagnosis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Self-diagnosis
date_saved: 2026-05-05T07:32:52.335800+00:00
instance: kb-cron
parent: self-diagnosis-20260505-0
summary:
Self-diagnosis itself is becoming a more lucrative industry given the popularity of self-testing kits. While these are most commonly associated with COVID-19, self-testing kits exist for a wide range of conditions, such as prostate cancer, Alzheimers, and menopause. Though healthcare professionals warn of their potential to be unreliable, these kits appeal to the public due to their easy use, convenience, and inexpensiveness. Despite the fact that doctors warn that they cannot necessarily conclusively diagnose a condition nor encapsulate a disease's full complexity, the industry creating these tests is growing in profitability. ==== Smartphone applications ==== Developers of medical diagnosis applications can also be fueled by commercial interests. A number of applications receive monetary returns for acting as referrals to health insurance companies, doctor's offices, and pharmacies. These forms of monetary compensation are often not mentioned in the app's contents or general overview. === The role of stigma === ==== Public stigma ==== Though self-diagnosis may work to counter the stigma associated with disease, it faces its own share of public disapproval. Those who publish posts encouraging self-diagnosis do not always have verified medical credentials even though they often present their posts as providing expert advice. As a result, self-diagnoses are


id: self-diagnosis-20260505-2
file: data/en.wikipedia.org/wiki/Self-diagnosis-2.md
category: reference
title: Self-diagnosis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Self-diagnosis
date_saved: 2026-05-05T07:32:52.335800+00:00
instance: kb-cron
parent: self-diagnosis-20260505-0
summary:
==== Use of chatbots ==== A recent technology that has started to take hold in the realm of self-diagnosis is the utilization of chatbot-based symptom checker (CSC) applications. CSCs were designed to combat the problem of extended wait times to see a doctor and the unavailability of punctual medical advice. Patients have also utilized chatbots to determine severity of their potential diagnosis before going through the process of seeing a doctor and incurring the financial strain that can come with it. Chatbots utilize artificial intelligence (AI) in order to assist patients in their medical concerns during all hours of the day. The operational mechanism of CSCs is a text-to-text system, where the chatbot asks a series of health-related questions in order to determine a diagnosis. The effectiveness of chatbots in the process of self-diagnosis is still highly debated among researchers. Studies have found that users have varying opinions on the required input for chatbot websites and applications. In some cases, chatbots offer limited space to input multiple symptoms and locations of symptoms for diagnosis determination. Interfaces have presented users with a "pre-structured symptom selection list" which has forced users to be more general with their responses than they would prefer.


id: self-diagnosis-20260505-3
file: data/en.wikipedia.org/wiki/Self-diagnosis-3.md
category: reference
title: Self-diagnosis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Self-diagnosis
date_saved: 2026-05-05T07:32:52.335800+00:00
instance: kb-cron
parent: self-diagnosis-20260505-0
summary:
==== The benefits and costs for vulnerable demographics ==== This trend of turning to self-diagnosis among minorities can be potentially dangerous, given the unfiltered and unauthorized information online. A report from Psychreg criticizes self-diagnosis for its potentially hazardous nature, reporting that 61% of the advice on social media (specifically, TikTok) is incorrect. The Camber Mental Health Organization also notes the potential danger of online self-diagnosis, indicating that influencers without proper license offer public advice that can further jeopardize the vulnerable demographics. Other studies present non-dangerous aspects of self-diagnosis for these populations. A new study published by the Department of Public Health and Primary Care at Leiden University Medical Centre explains that patients use the internet to find reliable medical information about minor ailments and thus prevent symptoms from worsening if immediate health care cannot be provided. After surveying 1,372 participants, the study finds that most patients utilize this symptom-based approach. Suppose the patients expect the potential diagnosis to be more lethal. In that case, they tend to conduct further research on the internet to verify their suspicions about their condition. === Age === Younger generations are more likely to perform self-diagnosis. Kwakernaak explains their findings of a positive correlation between


id: sequela-20260505-0
file: data/en.wikipedia.org/wiki/Sequela-0.md
category: reference
title: Sequela
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sequela
date_saved: 2026-05-05T07:33:04.576198+00:00
instance: kb-cron
parent: sequela-20260505-0
summary:
A sequela (UK: , US: ; usually used in the plural, sequelae ) is a pathological condition resulting from a disease, injury, therapy, or other trauma. Derived from the Latin word meaning "sequel", it is used in the medical field to mean a complication or condition following a prior illness or disease. A typical sequela is a chronic complication of an acute condition—in other words, a long-term effect of a temporary disease or injury—which follows immediately from the condition. Sequelae differ from late effects, which can appear long after—even several decades after—the original condition has resolved. In general, non-medical usage, the terms sequela and sequelae mean consequence and consequences. == Examples and uses == Chronic kidney disease, for example, is sometimes a sequela of diabetes; "chronic constipation" or more accurately "obstipation" (that is, inability to pass stool or gas) is a sequela to an intestinal obstruction; and neck pain is a common sequela of whiplash or other trauma to the cervical vertebrae. Post-traumatic stress disorder may be a psychological sequela of one or more traumatic events. Sequelae of traumatic brain injury include headache, dizziness, anxiety, apathy, depression, aggression, cognitive impairments, personality changes, mania, and psychosis. COVID-19 is also known to


id: sequence-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Sequence_(medicine)-0.md
category: reference
title: Sequence (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sequence_(medicine)
date_saved: 2026-05-05T07:33:05.738246+00:00
instance: kb-cron
parent: sequence-medicine-20260505-0
summary:
In medicine, a sequence is a series of ordered consequences due to a single cause. It differs from a syndrome in that seriality is more predictable: if A causes B, and B causes C, and C causes D, then D would not be seen if C is not seen. However, in less formal contexts, the term "syndrome" is sometimes used instead of sequence. Examples include: Oligohydramnios sequence (also known as Potter sequence) Pierre Robin sequence Poland sequence == References ==


id: seton-stitch-20260505-0
file: data/en.wikipedia.org/wiki/Seton_stitch-0.md
category: reference
title: Seton stitch
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seton_stitch
date_saved: 2026-05-05T07:33:07.036799+00:00
instance: kb-cron
parent: seton-stitch-20260505-0
summary:
A seton or seton stitch is a procedure used to aid the healing of fistulae (abnormal connections between two epithelium-lined organs or vessels). The word "seton" comes from the Medieval Latin sētōn, itself derived from sēta (meaning "bristle" or "hair") and the suffix -ōn. == Techniques == The procedure involves running a surgical-grade cord (eg, silk suture) through the fistula tract so that the cord creates a loop that joins up outside the fistula. The cord provides a path that allows the fistula to drain continuously while it is healing, rather than allowing the exterior of the wound to close over. Keeping the fistula tract open can help prevent the trapping of pus or other infectious material in the wound. The procedure was mentioned by Hippocrates. Setons can be tied tightly or loosely and with different materials, depending on the anatomical location of the fistulae and what may be medically required. A seton might be tied loosely as a palliative measure to avoid septic and painful exacerbations, or as temporary measure before surgical excision as in fistulotomy or fistulectomy. In some types of fistulae, a seton may be tied with more tension and tightened periodically. In this case, the seton


id: sever-s-disease-20260505-0
file: data/en.wikipedia.org/wiki/Sever's_disease-0.md
category: reference
title: Sever's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sever's_disease
date_saved: 2026-05-05T07:33:08.325773+00:00
instance: kb-cron
parent: sever-s-disease-20260505-0
summary:
Sever's disease, also known as calcaneal apophysitis, is an inflammation at the back of the heel (or calcaneus) growth plate in growing children. The condition is thought to be caused by repetitive stress at the heel. This condition is benign and common and usually resolves when the growth plate has closed or during periods of less activity. It occurs in both males and females. There are a number of locations in the body that may get apophysitis pain. Another common location is at the front of the knee which is known as apophysitis of the tibial tuberosity or Osgood–Schlatter disease. == Symptoms == Children with calcaneal apophysitis commonly complain of pain at the back of the heel. This pain increases with jumping and some running sports. Sometimes, the pain makes children limp and may result in poor sports performance or them not wanting to participate in some sports. The back of the heel is never swollen or red, unless there has been shoe rubbing. When the back of the heel is squeezed from the inside and outside, children with calcaneal apophysitis will report pain. Foot radiographs are not needed to diagnose calcaneal apophysitis as the growth plate can look similar


id: severity-of-illness-20260505-0
file: data/en.wikipedia.org/wiki/Severity_of_illness-0.md
category: reference
title: Severity of illness
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Severity_of_illness
date_saved: 2026-05-05T07:33:09.477032+00:00
instance: kb-cron
parent: severity-of-illness-20260505-0
summary:
Severity of illness (SOI) is defined as the extent of organ system derangement or physiologic decompensation for a patient. It gives a medical classification into minor, moderate, major, and extreme. The SOI class is meant to provide a basis for evaluating hospital resource use or to establish patient care guidelines. Patients are assigned their SOI based on their specific diagnoses and procedures performed during their medical encounter, which is generally an inpatient hospital stay. Patients with higher SOI (e.g. major or extreme) are more likely to consume greater healthcare resources and stay longer in hospitals than patients with lower SOI in the same diagnosis-related group (DRG). The Centers for Medicare and Medicaid Services considered the 3M APR-DRG and SOI system as a potential evolution to the DRG system in 2006, but received such negative feedback from the industry that in March 2007 decided to adopt another internally developed system evolved from the DRG. SOI is still commonly used throughout the United States to adjust for patient complexity, so that physicians and other groups can compare resource utilization, complication rates, and length of stay. == See also == Diagnosis-related group (DRG) Risk of mortality (ROM) Case mix index (CMI) Diagnosis code


id: sham-surgery-20260505-0
file: data/en.wikipedia.org/wiki/Sham_surgery-0.md
category: reference
title: Sham surgery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sham_surgery
date_saved: 2026-05-05T07:33:10.758867+00:00
instance: kb-cron
parent: sham-surgery-20260505-0
summary:
Sham surgery (or placebo surgery) is a faked surgical intervention that omits the step thought to be therapeutically necessary. In clinical trials of surgical interventions, sham surgery is an important scientific control. This is because it isolates the specific effects of the treatment as opposed to the incidental effects caused by anesthesia, the incisional trauma, pre- and postoperative care, and the patient's perception of having had a regular operation. Thus sham surgery serves an analogous purpose to placebo drugs, neutralizing biases such as the placebo effect. == Human research == A number of studies done under Institutional Review Board-approved settings have delivered important and surprising results. With the progress in minimally invasive surgery, sham procedures can be more easily performed as the sham incision can be kept small similarly to the incision in the studied procedure. A review of studies with sham surgery found 53 such studies: in 39 there was improvement with the sham operation and in 27 the sham procedure was as good as the real operation. Sham-controlled interventions have therefore identified interventions that are useless but had been believed by the medical community to be helpful based on studies without the use of sham surgery. === Examples


id: shit-life-syndrome-20260505-0
file: data/en.wikipedia.org/wiki/Shit_life_syndrome-0.md
category: reference
title: Shit life syndrome
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Shit_life_syndrome
date_saved: 2026-05-05T07:33:12.064135+00:00
instance: kb-cron
parent: shit-life-syndrome-20260505-0
summary:
Shit life syndrome (SLS) is a phrase used by physicians in the United Kingdom, the United States, and Australia for the effect that a variety of poverty or abuse-induced disorders can have on patients. == History == Sarah O'Connor's 2017 article for the Financial Times "Left behind: can anyone save the towns the economy forgot?" on shit life syndrome in the English coastal town of Blackpool won the 2018 Orwell Prize for Exposing Britain's Social Evils. O'Connor wrote that Blackpool exports healthy skilled people and imports the unskilled, the unemployed and the unwell. As people overlooked by the modern economy wash up in a place that has also been left behind, the result is a quietly unfolding health crisis. More than a tenth of the town's working-age inhabitants live on state benefits paid to those deemed too sick to work. Antidepressant prescription rates are among the highest in the country. Life expectancy, already the lowest in England, has recently started to fall. Doctors in places such as this have a private diagnosis for what ails some of their patients: "Shit Life Syndrome" ... People with SLS really do have mental or physical health problems, doctors say. But they believe the


id: simultanagnosia-20260505-0
file: data/en.wikipedia.org/wiki/Simultanagnosia-0.md
category: reference
title: Simultanagnosia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simultanagnosia
date_saved: 2026-05-05T07:33:13.374979+00:00
instance: kb-cron
parent: simultanagnosia-20260505-0
summary:
Simultanagnosia (or simultagnosia) is a rare neurological disorder characterized by the inability of an individual to visually perceive more than a single object at a time. This type of visual attention problem is one of three major components (the others being optic ataxia and optic apraxia) of Bálint's syndrome, an uncommon and incompletely understood variety of severe neuropsychological impairments involving space representation (visuospatial processing). The term "simultanagnosia" was first coined in 1924 by Wolpert to describe a condition where the affected individual could see individual details of a complex scene but failed to grasp the overall meaning of the image. Simultanagnosia can be divided into two different categories: dorsal and ventral. Ventral occipito-temporal lesions cause a mild form of the disorder, while dorsal occipito-parietal lesions cause a more severe form of the disorder. == Description == Patients with simultanagnosia, a component of Bálint's syndrome, have a restricted spatial window of visual attention and cannot see more than one object at a time in a scene that contains more than one object. For instance, if presented with an image of a table containing both food and various utensils, a patient will report seeing only one item, such as a spoon. If


id: simultanagnosia-20260505-1
file: data/en.wikipedia.org/wiki/Simultanagnosia-1.md
category: reference
title: Simultanagnosia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simultanagnosia
date_saved: 2026-05-05T07:33:13.374979+00:00
instance: kb-cron
parent: simultanagnosia-20260505-0
summary:
=== Restricted visual attention === In 1909, Rezső Bálint published one of the earliest descriptions of simultanagnosia. He studied a patient who easily identified single objects, regardless of size, but claimed that he could only see one object when presented with a complex display of numerous items. This patient also exhibited ocular apraxia, an impairment of voluntary eye movements despite intact oculomotor reflexes, and optic ataxia, or the impairment of visually guided hand movements. This collection of symptoms would later be called Bálint's syndrome. Because the size of the object did not affect his patient's ability to perceive an item, Bálint argued that his patient did not have a narrowing of the sensory field. Therefore, Bálint concluded that the patient's attention would always be as narrow as the size of the item being observed. In other words, the attentional window of a simultanagnosic patient is limited to one object. In contrast to Bálint's hypothesis, Thaiss and De Bleser studied a patient who had a physical restriction of her attentional window. The patient's ability to perceive multiple objects and identify global structures significantly improved as the size of the presented image decreased. Thus, complex stimuli could be processed as wholes so


id: simultanagnosia-20260505-2
file: data/en.wikipedia.org/wiki/Simultanagnosia-2.md
category: reference
title: Simultanagnosia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simultanagnosia
date_saved: 2026-05-05T07:33:13.374979+00:00
instance: kb-cron
parent: simultanagnosia-20260505-0
summary:
=== Spatial indexing deficits === Finally, simultanagnosia may result from deficits in spatial indexing. Several studies have noted that a pre-attentive stage of processing exists during which visual features are obtained from the visual field in parallel. Once these features have been extracted, they can be indexed, which allows them to function as anchor points for additional visual routines; visual routines are sequences of elemental operations, such as visual search or texture segregation, which define the spatial relationships among objects as well as their properties. Saliency of a feature facilitates the ease with which it can be indexed. For example, the greater the difference between a specific feature and surrounding ones, the more easily it can be indexed. The indexed features, or anchor points, can serve as a "spotlight" that directs focal attention to certain objects, which can then channel visual information to specialized systems for space and shape analysis. Deficits in the spatial indexing mechanism would result in symptoms of simultanagnosia because interpretation of a complex scene requires rapid shifting of attention to various elements, and impairments in spatial indexing lead to the inability to index multiple visual features rapidly. In addition, perception is slowed, and low-level visual processing


id: skull-bossing-20260505-0
file: data/en.wikipedia.org/wiki/Skull_bossing-0.md
category: reference
title: Skull bossing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Skull_bossing
date_saved: 2026-05-05T07:33:14.539213+00:00
instance: kb-cron
parent: skull-bossing-20260505-0
summary:
Skull bossing is a descriptive term in medical physical examination indicating a protuberance of the skull, most often in the frontal bones of the forehead ("frontal bossing"). Although prominence of the skull bones may be normal, skull bossing may be associated with certain medical conditions, including nutritional, metabolic, hormonal, and hematologic disorders. == Frontal bossing == Frontal bossing is the development of an unusually pronounced forehead which may also be associated with a heavier than normal brow ridge. It is caused by enlargement of the frontal bone, often in conjunction with abnormal enlargement of other facial bones, skull, mandible, and bones of the hands and feet. Frontal bossing may be seen in a few rare medical syndromes such as acromegaly – a chronic medical disorder in which the anterior pituitary gland produces excess growth hormone (GH). Frontal bossing may also occur in diseases resulting in chronic anemia, where there is increased hematopoiesis and enlargement of the medullary cavities of the skull. == Associated medical disorders == Rickets Achondroplasia Acromegaly Basal cell nevus syndrome Congenital syphilis Cleidocranial dysostosis Crouzon syndrome Cryopyrin-Associated Periodic Syndrome (CAPS – PFS) Ectodermal dysplasia Extramedullary hematopoiesis Fragile X syndrome Hurler syndrome Osteopathia Striata with Cranial Sclerosis Pfeiffer


id: slipped-capital-femoral-epiphysis-20260505-0
file: data/en.wikipedia.org/wiki/Slipped_capital_femoral_epiphysis-0.md
category: reference
title: Slipped capital femoral epiphysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Slipped_capital_femoral_epiphysis
date_saved: 2026-05-05T07:33:15.712162+00:00
instance: kb-cron
parent: slipped-capital-femoral-epiphysis-20260505-0
summary:
Slipped capital femoral epiphysis (SCFE, or skiffy), or slipped upper femoral epiphysis (SUFE, or souffy), or coxa vara adolescentium, is a medical term referring to a fracture through the growth plate (physis), which results in slippage of the overlying end of the femur (metaphysis). Normally, the head of the femur, called the caput femoris in Latin, should sit squarely on the femoral neck. Abnormal movement along the growth plate results in the slip. The term slipped capital femoral epiphysis is actually a misnomer, because the epiphysis (end part of a bone) remains in its normal anatomical position in the acetabulum (hip socket) due to the ligamentum teres femoris. It is actually the metaphysis (neck part of a bone) which slips in an anterior direction with external rotation. SCFE is the most common hip disorder in adolescence. SCFEs usually cause groin pain on the affected side, but sometimes cause knee or thigh pain. One in five cases involves both hips, resulting in pain on both sides of the body. SCFE occurs slightly more commonly in adolescent males, especially young black males, although it also affects females. Whilst it can occur in any child, the major risk factor is childhood obesity. Symptoms


id: slipped-capital-femoral-epiphysis-20260505-1
file: data/en.wikipedia.org/wiki/Slipped_capital_femoral_epiphysis-1.md
category: reference
title: Slipped capital femoral epiphysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Slipped_capital_femoral_epiphysis
date_saved: 2026-05-05T07:33:15.712162+00:00
instance: kb-cron
parent: slipped-capital-femoral-epiphysis-20260505-0
summary:
The diagnosis requires x-rays of the pelvis, with anteriorposterior (AP) and frog-leg lateral views. The appearance of the head of the femur in relation to the shaft likens that of a "melting ice cream cone", visible with Klein's line. The severity of the disease can be measured using the Southwick angle. === Classification === Atypical/Typical Loder classification Stable Unstable, practically defined as when the patient is unable to ambulate even with crutches Temporal Acute Chronic Acute-on-chronic Radiological Grade I = 0–33% slippage Grade II = 34–50% slippage Grade III = >50% slippage == Treatment == The disease can be treated with external in-situ pinning or open reduction and pinning. Consultation with an orthopaedic surgeon is necessary to repair this problem. Pinning the unaffected side prophylactically is not recommended for most patients, but may be appropriate if a second SCFE is very likely. Once SCFE is suspected, the patient should be non-weight bearing and remain on strict bed rest. In severe cases, after enough rest the patient may require physical therapy to regain strength and movement back to the leg. A SCFE is an orthopaedic emergency, as further slippage may result in occlusion of the blood supply and avascular necrosis (risk


id: slips-and-capture-20260505-0
file: data/en.wikipedia.org/wiki/Slips_and_capture-0.md
category: reference
title: Slips and capture
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Slips_and_capture
date_saved: 2026-05-05T07:33:16.969113+00:00
instance: kb-cron
parent: slips-and-capture-20260505-0
summary:
A slips and capture error is a type of human error in the psychology of routine task performance, where a person inadvertently performs one action while intending to do another, often under high-stress conditions. It is a specific subset of action slips, which encompass a broader range of errors in automatic behaviors caused by lapses in attention, habitual actions, or environmental design. The term "slips and capture" became more widely known in the early 21st century in the United States, after being referred to by law enforcement in two prominent fatal police shooting cases in 2009 and 2015. In both cases, the police officer claimed to have shot a suspect while intending to use a Taser. == Background and history == The concept of "slips and capture" has been studied in the psychology of human error, and efforts to prevent error. It was thoroughly described in 1990 by James Reason. The concept has been addressed in efforts to improve business, including computer and program design, and medical practices in order to avoid preventable error. Both terms are used in error terminology: slips are defined as "errors in the performance of skill-based behaviors, typically when our attention is diverted;" and capture


id: soap-note-20260505-0
file: data/en.wikipedia.org/wiki/SOAP_note-0.md
category: reference
title: SOAP note
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SOAP_note
date_saved: 2026-05-05T07:33:18.158983+00:00
instance: kb-cron
parent: soap-note-20260505-0
summary:
The SOAP note (an acronym for subjective, objective, assessment, and plan) is a method of documentation employed by healthcare providers to write out notes in a patient's chart, along with other common formats, such as the admission note. Documenting patient encounters in the medical record is an integral part of practice workflow starting with appointment scheduling, patient check-in and exam, documentation of notes, check-out, rescheduling, and medical billing. Additionally, it serves as a general cognitive framework for physicians to follow as they assess their patients. The SOAP note originated from the problem-oriented medical record (POMR), developed nearly 50 years ago by Lawrence Weed, MD. It was initially developed for physicians to allow them to approach complex patients with multiple problems in a highly organized way. Today, it is widely adopted as a communication tool between inter-disciplinary healthcare providers as a way to document a patient's progress. SOAP notes are commonly found in electronic medical records (EMR) and are used by providers of various backgrounds. Generally, SOAP notes are used as a template to guide the information that physicians add to a patient's EMR. Prehospital care providers such as emergency medical technicians may use the same format to communicate patient information


id: soap-note-20260505-1
file: data/en.wikipedia.org/wiki/SOAP_note-1.md
category: reference
title: SOAP note
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SOAP_note
date_saved: 2026-05-05T07:33:18.158983+00:00
instance: kb-cron
parent: soap-note-20260505-0
summary:
=== Plan component === The plan is what the health care provider will do to treat the patient's concerns—such as ordering further labs, radiological work up, referrals given, procedures performed, medications given and education provided. The plan will also include goals of therapy and patient-specific drug and disease-state monitoring parameters. This should address each item of the differential diagnosis. For patients who have multiple health problems that are addressed in the SOAP note, a plan is developed for each problem and is numbered accordingly based on severity and urgency for therapy. A note of what was discussed or advised with the patient as well as timings for further review or follow-up are generally included. Often the Assessment and Plan sections are grouped together. == An example == A very rough example follows for a patient being reviewed following an appendectomy. This example resembles a surgical SOAP note; medical notes tend to be more detailed, especially in the subjective and objective sections. The plan itself includes various components: Diagnostic component: continue to monitor labs Therapeutic component: advance diet Referrals: follow up with Cardiology within three days of discharge for stress testing as an out-patient. Patient education component: that is progressing well


id: social-history-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Social_history_(medicine)-0.md
category: reference
title: Social history (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Social_history_(medicine)
date_saved: 2026-05-05T07:33:19.336796+00:00
instance: kb-cron
parent: social-history-medicine-20260505-0
summary:
In medicine, a social history (abbreviated "SocHx") is a portion of the medical history (and thus the admission note) addressing familial, occupational, and recreational aspects of the patient's personal life that have the potential to be clinically significant. == Components == Components can include inquiries about: Substances Alcohol Tobacco (pack years) illicit drugs occupation sexual behavior (increased risk of various infections among prostitutes, people who have sex with people for money, and males engaging in anal-receptive intercourse) prison (especially if tuberculosis needs to be ruled out) travel exercise diet Firearms in household (especially if children or persons with cognitive impairment are present) == Relation to history == == References ==


id: social-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Social_medicine-0.md
category: reference
title: Social medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Social_medicine
date_saved: 2026-05-05T07:33:20.577714+00:00
instance: kb-cron
parent: social-medicine-20260505-0
summary:
Social medicine is an interdisciplinary field that focuses on the interplay between socio-economic factors and individual health outcomes. Rooted in the challenges of the Industrial Revolution, it seeks to: Understand how specific social, economic, and environmental conditions directly impact health, disease, and the delivery of medical care. Promote conditions and interventions that address these determinants, aiming for a healthier and more equitable society. Social medicine as a scientific field gradually began in the early 19th century in Europe, during the Industrial Revolution and the subsequent increase in poverty and disease among workers raised concerns about the effect of social processes on the health of the poor. The field of social medicine is most commonly addressed today by efforts to understand what are known as social determinants of health. == Scope == The major emphasis on biomedical science in medical education, health care, and medical research has resulted into a gap with our understanding and acknowledgement of far more important social determinants of health and individual disease: social-economic inequalities, war, illiteracy, detrimental life-styles (smoking, obesity), discrimination because of race, gender and religion. Farmer et al. (2006) gave the following explanation for this gap: The holy grail of modern medicine remains the


id: social-prescribing-20260505-0
file: data/en.wikipedia.org/wiki/Social_prescribing-0.md
category: reference
title: Social prescribing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Social_prescribing
date_saved: 2026-05-05T07:33:21.908886+00:00
instance: kb-cron
parent: social-prescribing-20260505-0
summary:
Social prescribing (also known as community referral) is a process through which a person is referred to non-medical, community-based resources or activities, typically involving nature, art, movement, and service. In the UK, a Social Prescribing Link Worker may engage with a patient to support them with a plan which can be a series of signposting or referrals to support in the community, in order to improve their health and wellbeing. The concept has gained support in the NHS organisations of the United Kingdom as well as in Ireland and the Netherlands and forms part of the NHS Long Term Plan. The referral mechanisms, target groups, services offered through social prescribing vary across settings. However, the process usually involves screening for non-medical needs and referrals to support services that are typically offered by community-based organizations. The goals of social prescribing are to reduce the rise of healthcare costs and easing pressure of general practice clinics. A 2015 Commission in the UK estimated that about 20% of patient consultations were for social problems rather than medical problems. Reporting finds social prescribing has been effective for treating symptoms of depression, ADHD, anxiety, chronic pain, dementia, type 2 diabetes, loneliness, and more. == Definition


id: social-emotional-agnosia-20260505-0
file: data/en.wikipedia.org/wiki/Social-emotional_agnosia-0.md
category: reference
title: Social-emotional agnosia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Social-emotional_agnosia
date_saved: 2026-05-05T07:33:23.093741+00:00
instance: kb-cron
parent: social-emotional-agnosia-20260505-0
summary:
Social-emotional agnosia, also known as emotional agnosia or expressive agnosia, is the inability to perceive facial expressions, body language, and voice intonation. A person with this disorder is unable to non-verbally perceive others' emotions in social situations, limiting normal social interactions. The condition causes a functional blindness to subtle non-verbal social-emotional cues in voice, gesture, and facial expression. People with this form of agnosia have difficulty in determining and identifying the motivational and emotional significance of external social events, and may appear emotionless or agnostic (uncertainty or general indecisiveness about a particular thing). Symptoms of this agnosia can vary depending on the area of the brain affected. Social-emotional agnosia often occurs in individuals with schizophrenia and autism. It is difficult to distinguish from, and has been found to co-occur with, alexithymia. == Presentation == Damage to the right temporal occipital region in humans has been associated with the inability to recognize the faces of loved ones, friends, and pets (considered a form of prosopagnosia). This limits the ability to appropriately interact with familiar people, potentially severely damaging interpersonal relationships. People with social-emotional agnosia may distance themselves from interacting with other people and prefer isolation. Maternal behavior is also severely affected,


id: sopor-sleep-20260505-0
file: data/en.wikipedia.org/wiki/Sopor_(sleep)-0.md
category: reference
title: Sopor (sleep)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sopor_(sleep)
date_saved: 2026-05-05T07:33:24.253907+00:00
instance: kb-cron
parent: sopor-sleep-20260505-0
summary:
Sopor is a condition of abnormally deep sleep, similar to a stupor but not as severe, from which it is difficult to rouse a person. It involves a profound depression of consciousness, which is manifested by drowsiness, while maintaining coordinated defensive reactions to stimuli such as pain, harsh sound, and bright light, and preserving vital functions. Sopor may be caused by a drug; such drugs are deemed soporific. A stupor is more severe than a sopor. The name is derived from Latin sopor (cognate with the Latin noun somnus and the Greek noun ὐπνος, hypnos). == Causes and symptoms == Soporous states can be caused by traumatic, vascular, inflammatory, neoplastic, or toxic lesions of the brain. Symptoms include lack of response to the environment and inability to perform any tasks or respond to questions. The ability to swallow is maintained. Examination will reveal decreased muscle tone of the extremities and depression of tendon reflexes. Pupillary reaction to light may be sluggish, but the corneal reflexes are preserved. Paresis and Babinski sign may be present. == References ==


id: speech-language-pathology-20260505-0
file: data/en.wikipedia.org/wiki/Speech–language_pathology-0.md
category: reference
title: Speech–language pathology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Speech–language_pathology
date_saved: 2026-05-05T07:33:25.561268+00:00
instance: kb-cron
parent: speech-language-pathology-20260505-0
summary:
Speech–language pathology, also known as speech and language pathology or logopedics, is a healthcare and academic discipline concerning the evaluation, treatment, and prevention of communication disorders, including expressive and mixed receptive-expressive language disorders, voice disorders, speech sound disorders, speech disfluency, pragmatic language impairments, and social communication difficulties, as well as swallowing disorders across the lifespan. The field of speech-language pathology is practiced by a clinician known as a speech–language pathologist (SLP) or a speech and language therapist (SLT). It is an allied health profession regulated by professional state licensing boards in the United States of America, and Speech Pathology Australia. The American Speech–Language–Hearing Association (ASHA) monitors state laws, lobbies, and advocates for SLPs. == History == The development of speech-language pathology into a profession took different paths in the various regions of the world. Three identifiable trends influenced the evolution of speech-language pathology in the United States during the late 19th century to early 20th century: the elocution movement, scientific revolution, and the rise of professionalism. Groups of "speech correctionists" formed in the early 1900s. The American Academy of Speech Correction was founded in 1925, which became ASHA in 1978. == Profession == Speech–language pathologists (SLPs) provide a wide range


id: speech-language-pathology-20260505-1
file: data/en.wikipedia.org/wiki/Speech–language_pathology-1.md
category: reference
title: Speech–language pathology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Speech–language_pathology
date_saved: 2026-05-05T07:33:25.561268+00:00
instance: kb-cron
parent: speech-language-pathology-20260505-0
summary:
Following ASHA's 2005 approval of the delivery of speech/language services via video conference or telepractice, SLPs in the United States have begun to use this service model. Children with speech, language, and communication needs (SLCN) are particularly at risk of not being heard because of communication challenges. Speech-language pathologists (SLPs) can explain the significance of supporting communication as a tool for the child to shape and influence choices available to them in their lives, even though it is advised that children with SLCN can and should be actively involved as equal partners in decision-making about their communication needs. Building these skills is especially crucial for SLPs working in settings related to traditional education. === Research === SLPs conduct research related to communication sciences and disorders, swallowing disorders, or other upper aerodigestive functions. Experimental, empirical, and scientific methodologies that build on hypothesis testing and logical, deductive reasoning have dominated research in speech-language pathology. Other types of research in the field are complemented by qualitative research. === Education and training === ==== United States ==== In the United States, speech–language pathologists must hold a master's degree from an ASHA-accredited program. Following graduation and passing a nation-wide board exam, SLPs typically begin their


id: speech-language-pathology-20260505-2
file: data/en.wikipedia.org/wiki/Speech–language_pathology-2.md
category: reference
title: Speech–language pathology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Speech–language_pathology
date_saved: 2026-05-05T07:33:25.561268+00:00
instance: kb-cron
parent: speech-language-pathology-20260505-0
summary:
=== Adults === Adults with aphasia Adults with mild, moderate, or severe eating, feeding and swallowing difficulties, including dysphagia Adults recovering from significant tumors in the bronchus, lung, oropharynx, breast, and brain Adults with mild, moderate, or severe language difficulties as a result of: Motor neuron diseases, Alzheimer's disease, Dementia, Huntington's disease, Hearing loss Multiple sclerosis, Parkinson's disease, Traumatic brain injury, Mental health issues Stroke Progressive neurological conditions such as cancer of the head, neck and throat (including laryngectomy) Aphasic Adults seeking transgender-specific voice training, including voice feminization and voice masculinization == See also == == References == == Further reading == Fisher, S. E.; Scharff, C. (April 2009). "FOXP2 as a molecular window into speech and language". Trends in Genetics. 25 (4): 166–77. doi:10.1016/j.tig.2009.03.002. hdl:11858/00-001M-0000-0012-CA31-7. PMID 19304338. "Discussion Meeting Issue 'Language in developmental and acquired disorders: converging evidence for models of language representation in the brain' - Table of Contents". Royal Society Publishing. 2014. Retrieved 31 December 2013. Nelson, H. D. (1 February 2006). "Screening for Speech and Language Delay in Preschool Children: Systematic Evidence Review for the US Preventive Services Task Force". Pediatrics. 117 (2): e298–e319. doi:10.1542/peds.2005-1467. PMID 16452337. Howell, Peter (2011). Recovery from stuttering. New York: Psychology


id: spikes-20260505-0
file: data/en.wikipedia.org/wiki/SPIKES-0.md
category: reference
title: SPIKES
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SPIKES
date_saved: 2026-05-05T07:33:26.854955+00:00
instance: kb-cron
parent: spikes-20260505-0
summary:
The SPIKES protocol is a method used in clinical medicine to break bad news to patients and families. As receiving emotionally distressing information can cause distress and anxiety, clinicians need to deliver the news carefully. Using the SPIKES method is an acronym for introducing and communicating information to patients and their families, can aid in the presentation of the material. The SPIKES method is helpful in providing an organized manner of communication during situations that are typically complex and difficult to communicate. This method has received praises and criticism, while majorly influencing clinician-patient communication. According to research related to the SPIKES method, important factors to consider when using this protocol involve empathy, acknowledgement, culture, and validation of feelings, providing information about intervention and treatment, and ensuring that the patient clearly understands the news being delivered. The protocol was first published in 2000 by Baile et al, in the context of oncology. == Steps == The name SPIKES is an acronym, where the letters stand for: S: setting, i.e. setting up the consultation appropriately: → The patient should only be provided with the bad news when they are in a private setting that contains little to no distractions to ensure the


id: spinnbarkeit-20260505-0
file: data/en.wikipedia.org/wiki/Spinnbarkeit-0.md
category: reference
title: Spinnbarkeit
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spinnbarkeit
date_saved: 2026-05-05T07:33:28.059365+00:00
instance: kb-cron
parent: spinnbarkeit-20260505-0
summary:
Spinnbarkeit (English: spinnability), also known as fibrosity, is a biomedical rheology term which refers to the stringy or stretchy property found to varying degrees in mucus, saliva, albumen and similar viscoelastic fluids. The term is used especially with reference to cervical mucus at the time just prior to or during ovulation. Under the influence of estrogens, cervical mucus becomes abundant, clear, and stretchable, and somewhat like egg white. The stretchability of the mucus is described by its spinnbarkeit, from the German word for the ability to be spun. Only such mucus appears to be able to be penetrated by sperm. After ovulation, the character of cervical mucus changes, and under the influence of progesterone it becomes thick, scant, and tacky. Sperm typically cannot penetrate it. Saliva does not always exhibit spinnbarkeit, but it can under certain circumstances. The thickness and spinnbarkeit of nasal mucus are factors in whether or not the nose seems to be blocked. Mucociliary transport depends on the interaction of fibrous mucus with beating cilia. == See also == Mucorrhea == References ==


id: spontaneous-breathing-trial-20260505-0
file: data/en.wikipedia.org/wiki/Spontaneous_breathing_trial-0.md
category: reference
title: Spontaneous breathing trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spontaneous_breathing_trial
date_saved: 2026-05-05T07:33:29.264970+00:00
instance: kb-cron
parent: spontaneous-breathing-trial-20260505-0
summary:
A spontaneous breathing trial (SBT) is a test for patients on mechanical ventilation, before they can be extubated and liberated from mechanical ventilation, i.e. return to normal breathing. SBTs are daily tests performed on intubated patients to determine if they meet criteria for extubation. The SBT involves placing the patient on minimal ventilatory support for a set period, typically 30–120 minutes, and under close monitoring. There are two common methods: In a T-Piece Trial, the ventilator is completely removed, and the patient breathes through a T-piece connected to the endotracheal tube and supplied with humidified oxygen. Because no ventilatory support is provided, this provides a pure test of the patient’s ability to breathe independently, and is more challenging. More commonly, low-level pressure support ventilation can be used, providing some inspiratory pressure (typically 5-8 cmH₂O) with or without Positive End-Expiratory Pressure (PEEP) (usually ≤5 cmH₂O). Automatic tube compensation (ATC) or minimal PSV helps patients overcome the added resistance of the endotracheal tube. This method is easier than a T-piece trial and is commonly used in ICU settings. Patients are more likely to be successfully extubated after a PSV trial compared to a T-piece trial. Spontaneous breathing trials (SBT) are often combined


id: spontaneous-remission-20260505-0
file: data/en.wikipedia.org/wiki/Spontaneous_remission-0.md
category: reference
title: Spontaneous remission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spontaneous_remission
date_saved: 2026-05-05T07:33:30.611981+00:00
instance: kb-cron
parent: spontaneous-remission-20260505-0
summary:
Spontaneous remission, also called spontaneous healing or spontaneous regression, is an unexpected improvement or cure from a disease that usually progresses. These terms are commonly used for unexpected transient or final improvements in cancer. Spontaneous remissions concern cancers of the haematopoietic system (blood cancer, e.g., leukemia), while spontaneous regressions concern palpable tumors; however, both terms are often used interchangeably. == Definition == The spontaneous regression and remission from cancer was defined by Everson and Cole in their 1966 book as "the partial or complete disappearance of a malignant tumour in the absence of all treatment, or in the presence of therapy which is considered inadequate to exert significant influence on neoplastic disease." == Frequency of spontaneous regression in cancer == It has long been assumed that spontaneous regressions, let alone cures, from cancer are rare phenomena, and that some forms of cancer are more prone to unexpected courses (melanoma, neuroblastoma, lymphoma) than others (carcinoma). Frequency was estimated to be about 1 in 100,000 cancers; however, this proportion might be an under- or an overestimate. For one, not all cases of spontaneous regression can be apprehended, either because the case was not well documented or the physician was not willing to


id: status-cribrosum-20260505-0
file: data/en.wikipedia.org/wiki/Status_cribrosum-0.md
category: reference
title: Status cribrosum
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Status_cribrosum
date_saved: 2026-05-05T07:33:31.884759+00:00
instance: kb-cron
parent: status-cribrosum-20260505-0
summary:
Status cribrosum (French: état criblé) is a term used in neuropathology and neuroimaging for diffuse widening of perivascular (Virchow–Robin) spaces, most often in the basal ganglia, producing a "sieve-like" (cribriform) appearance of the affected brain tissue. == Appearance == In the brain, perivascular spaces are fluid-filled compartments that accompany small penetrating vessels as they course from the subarachnoid space into the brain parenchyma. Dilated perivascular spaces most often occur in characteristic locations (for example, along the lenticulostriate arteries in the basal ganglia) and have signal characteristics identical to cerebrospinal fluid on routine MRI sequences. When perivascular spaces are numerous and markedly enlarged in the basal ganglia, the resulting cribriform appearance is termed status cribrosum (état criblé). Status cribrosum is most often recognized on MRI. They are often seen along lenticulostriate vessels bilaterally and symmetrically, showing CSF-like signal without restricted diffusion. == Epidemiology == MRI-visible perivascular spaces are common in older adults. Status cribrosum represents an extreme pattern. In the population-based 3C-Dijon study of 1,826 elderly participants, status cribrosum was reported in 1.3% of participants. == Clinical significance == Status cribrosum is frequently an incidental imaging finding and its direct clinical correlates remain uncertain. When the cribriform appearance is especially prominent


id: stenosis-20260505-0
file: data/en.wikipedia.org/wiki/Stenosis-0.md
category: reference
title: Stenosis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Stenosis
date_saved: 2026-05-05T07:33:33.001290+00:00
instance: kb-cron
parent: stenosis-20260505-0
summary:
Stenosis (from Ancient Greek στενός (stenós) 'narrow') is the abnormal narrowing of a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture). Stricture as a term is usually used when narrowing is caused by contraction of smooth muscle (e.g. achalasia, Prinzmetal angina); stenosis is usually used when narrowing is caused by lesion that reduces the space of lumen (e.g. atherosclerosis). The term coarctation is another synonym, but is commonly used only in the context of aortic coarctation. Restenosis is the recurrence of stenosis after a procedure. == Examples == Examples of vascular stenotic lesions include: Intermittent claudication (peripheral artery stenosis) Angina (coronary artery stenosis) Carotid artery stenosis which predispose to (strokes and transient ischemic episodes) Renal artery stenosis == Types == === Vascular Stenosis === Arterial stenosis Carotid artery stenosis Coronary artery stenosis Renal artery stenosis Peripheral artery stenosis Vertebral artery stenosis Cerebral artery stenosis Pulmonary artery stenosis Congenital or acquired abnormal narrowing of pulmonary arteries along any portion of the pulmonary artery tree Venous stenosis Jugular venous stenosis Central venous stenosis === Cardiac Valve Stenosis === In order from most to least common: Aortic


id: subclinical-infection-20260505-0
file: data/en.wikipedia.org/wiki/Subclinical_infection-0.md
category: reference
title: Subclinical infection
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Subclinical_infection
date_saved: 2026-05-05T07:33:34.231364+00:00
instance: kb-cron
parent: subclinical-infection-20260505-0
summary:
A subclinical infection—sometimes called a preinfection or inapparent infection—is an infection by a pathogen that causes few or no signs or symptoms of infection in the host. Subclinical infections can occur in both humans and animals. Depending on the pathogen, which can be a virus or intestinal parasite, the host may be infectious and able to transmit the pathogen without ever developing symptoms; such a host is called an asymptomatic carrier. Many pathogens, including HIV, typhoid fever, and coronaviruses such as COVID-19 spread in their host populations through subclinical infection. Not all hosts of asymptomatic subclinical infections will become asymptomatic carriers. For example, hosts of Mycobacterium tuberculosis bacteria will only develop active tuberculosis in approximately one-tenth of cases; the majority of those infected by Mtb bacteria have latent tuberculosis, a non-infectious type of tuberculosis that does not produce symptoms in individuals with sufficient immune responses. Because subclinical infections often occur without eventual overt sign, in some cases their presence is only identified by microbiological culture or DNA techniques such as polymerase chain reaction (PCR) tests. == Transmission == === In humans === Many pathogens are transmitted through their host populations by hosts with few or no symptoms, including sexually transmitted


id: subluxation-20260505-0
file: data/en.wikipedia.org/wiki/Subluxation-0.md
category: reference
title: Subluxation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Subluxation
date_saved: 2026-05-05T07:33:35.434206+00:00
instance: kb-cron
parent: subluxation-20260505-0
summary:
A subluxation is an incomplete or partial dislocation of a joint or organ. According to the World Health Organization, a subluxation is a "significant structural displacement" and is therefore visible on static imaging studies, such as X-rays. Unlike real subluxations, the pseudoscientific concept of a chiropractic "vertebral subluxation" may or may not be visible on x-rays. The term is used in the fields of medicine, dentistry, and chiropractic. There is no scientific evidence for the existence of chiropractic subluxations or proof they or their treatment have any effects on health. == Medical == === Joints === A subluxation of a joint is where a connecting bone is partially out of the joint. In contrast to a luxation, which is a complete separation of the joint, a subluxation often returns to its normal position without additional help from a health professional. An example of a joint subluxation is a nursemaid's elbow, which is the subluxation of the head of the radius from the annular ligament. Other joints that are prone to subluxations are the shoulders, fingers, kneecaps, ribs, wrists, ankles, and hips affected by hip dysplasia. A spinal subluxation is visible on X-rays and can sometimes impinge on spinal nerve roots,


id: sudden-unexpected-death-in-epilepsy-20260505-0
file: data/en.wikipedia.org/wiki/Sudden_unexpected_death_in_epilepsy-0.md
category: reference
title: Sudden unexpected death in epilepsy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sudden_unexpected_death_in_epilepsy
date_saved: 2026-05-05T07:33:36.743907+00:00
instance: kb-cron
parent: sudden-unexpected-death-in-epilepsy-20260505-0
summary:
Sudden unexpected death in epilepsy (SUDEP) is the sudden, unexpected death of a person with epilepsy that is not the result of trauma, drowning, or an identified medical condition. In most cases, no structural or toxicological cause of death is found at autopsy. SUDEP can occur with or without evidence of a preceding seizure, and is often unwitnessed, especially during sleep. The exact mechanisms underlying SUDEP remain unclear but are believed to be multifactorial. Potential contributors include seizure-related disruptions in breathing, heart rhythm, or brain function, often in combination. SUDEP is estimated to affect approximately 1 in 1,000 adults and 1 in 4,500 children with epilepsy each year. It accounts for 7% to 17% of epilepsy-related deaths overall, and up to 50% in those with refractory epilepsy. Deaths caused by status epilepticus or accidents such as drowning are classified separately. == Definition == To improve consistency in clinical reporting and research, a unified classification system for SUDEP has been proposed. It defines SUDEP as a sudden, unexpected, nontraumatic, and nondrowning death in a person with epilepsy, occurring in benign circumstances, with or without evidence of a seizure, and without a known structural or toxicological cause identified on postmortem examination. Deaths


id: sudden-unexpected-death-in-epilepsy-20260505-1
file: data/en.wikipedia.org/wiki/Sudden_unexpected_death_in_epilepsy-1.md
category: reference
title: Sudden unexpected death in epilepsy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sudden_unexpected_death_in_epilepsy
date_saved: 2026-05-05T07:33:36.743907+00:00
instance: kb-cron
parent: sudden-unexpected-death-in-epilepsy-20260505-0
summary:
=== Cardiac mechanisms === Seizure-related cardiac abnormalities, including ictal arrhythmias, have been implicated in some cases of SUDEP. Ictal asystole, defined as seizure-related cessation of cardiac activity, is rare but well-documented, particularly in individuals with temporal lobe epilepsy. However, most seizure-related arrhythmias are transient and self-limiting. While arrhythmias can occur during seizures, most evidence suggests that in SUDEP, cardiac arrest typically results from respiratory failure. In monitored cases, including those from the MORTEMUS study, bradycardia and asystole consistently followed the onset of postictal apnea; no cases showed cardiac arrest preceding respiratory arrest. This pattern supports a neurogenic origin for SUDEP, with respiratory failure triggering secondary cardiac arrest rather than a primary cardiac event. === Central and autonomic nervous system dysfunction === Dysfunction of central and autonomic nervous system pathways may contribute to SUDEP by impairing the regulation of breathing, cardiac rhythm, and arousal. The brainstem plays a key integrative role in coordinating these functions, and seizure-related disruption of its regulatory circuits is believed to underlie many fatal cases. One proposed marker of cerebral dysfunction is postictal generalized EEG suppression (PGES), a transient period of low-amplitude activity on electroencephalography following a generalized seizure. PGES has been interpreted as evidence of widespread


id: sudomotor-20260505-0
file: data/en.wikipedia.org/wiki/Sudomotor-0.md
category: reference
title: Sudomotor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sudomotor
date_saved: 2026-05-05T07:33:37.926561+00:00
instance: kb-cron
parent: sudomotor-20260505-0
summary:
Sudomotor function refers to the autonomic nervous system control of sweat gland activity in response to various environmental and individual factors. Sweat production is a vital thermoregulatory mechanism used by the body to prevent heat-related illness as the evaporation of sweat is the body's most effective method of heat reduction and the only cooling method available when the air temperature rises above skin temperature. In addition, sweat plays key roles in grip, microbial defense, and wound healing. == Physiology == Human sweat glands are primarily classified as either eccrine or apocrine glands. Eccrine glands open directly onto the surface of the skin, while apocrine glands open into hair follicles. Eccrine glands are the predominant sweat gland in the human body with numbers totaling up to 4 million. They are located within the reticular dermal layer of the skin and distributed across nearly the entire surface of the body with the largest numbers occurring in the palms and soles. Eccrine sweat is secreted in response to both emotional and thermal stimulation. Eccrine glands are primarily innervated by small-diameter, unmyelinated class C-fibers from postganglionic sympathetic cholinergic neurons. Increases in body and skin temperature are detected by visceral and peripheral thermoreceptors, which send


id: sudomotor-20260505-1
file: data/en.wikipedia.org/wiki/Sudomotor-1.md
category: reference
title: Sudomotor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sudomotor
date_saved: 2026-05-05T07:33:37.926561+00:00
instance: kb-cron
parent: sudomotor-20260505-0
summary:
=== Quantitative sudomotor axon reflex test === The quantitative sudomotor axon reflex test (QSART) was developed in 1983 by Phillip Low as a quantitative method for the identification of localized postganglionic sudomotor dysfunction. Three-compartment sweat capsules are placed on the forearm, proximal and distal leg, as well as the dorsum of the foot. The outer compartment of the capsule is filled with a 10% acetylcholine solution, while nitrogen gas is released steadily onto the skin within the inner compartment. The middle compartment acts as a buffer between the inner and outer compartments to prevent direct stimulation of sweat glands or leakage of the acetylcholine solution. The outflow humidity of the nitrogen gas after passing across the skin is measured by a hygrometer. Once a stable baseline of outflow humidity is reached, iontophoresis of the acetylcholine fluid is initiated by using a 2mA electric current to deliver the acetylcholine into the dermal skin layers. The acetylcholine binds to sweat glands (direct sweat response), and nicotinic and muscarinic receptors on the sudomotor nerve terminals, which transmit the action potential antidromically to axon branch points and then orthodromically to adjacent sudomotor nerves and glands (indirect sweat response). Sweat production is measured as the


id: sudomotor-20260505-2
file: data/en.wikipedia.org/wiki/Sudomotor-2.md
category: reference
title: Sudomotor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sudomotor
date_saved: 2026-05-05T07:33:37.926561+00:00
instance: kb-cron
parent: sudomotor-20260505-0
summary:
=== Silicone imprint method === Like QSART, silicone imprint utilizes the principles of iontophoresis to measure the axon-reflex sweat response; however, unlike QSART, it allows for spatial but not temporal resolution of the sweat response. Following iontophoresis of a cholinergic agonist, a thin layer of silicone is applied to the tested skin area until polymerization is complete (about 5 minutes). The silicone imprints are then analyzed, either by microscope or computer-assisted analysis, for sweat droplet size, number, and distribution, and compared to lower limits of normal. The silicone imprint method is relatively inexpensive and can be performed in non-specialized testing centers; however, the method is prone to artifacts caused by residual hair and dirt, as well as skin surface texture and air bubble formation; the accuracy of the results depends on the silicone material used; the processing of the sweat impressions is time consuming; and the technique requires standardization. === Quantitative direct and indirect test === The quantitative direct and indirect test (QDIRT) was developed in 2008 by Christopher Gibbons and colleagues as a means for the evaluation of postganglionic sudomotor function outside of specialized autonomic testing centers. It combines elements of TST, QSART, and the silicone imprint method. Similar


id: sudomotor-20260505-3
file: data/en.wikipedia.org/wiki/Sudomotor-3.md
category: reference
title: Sudomotor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sudomotor
date_saved: 2026-05-05T07:33:37.926561+00:00
instance: kb-cron
parent: sudomotor-20260505-0
summary:
== See also == Sweat gland Eccrine sweat gland Electrochemical skin conductance == References == == Further reading == Agashe, Shruti; Petak, Steven (2018). "Cardiac Autonomic Neuropathy in Diabetes Mellitus". Methodist DeBakey Cardiovascular Journal. 14 (4): 251–256. doi:10.14797/mdcj-14-4-251. PMC 6369622. PMID 30788010. Itch, Hiroshi; Uebori, Seiji; Asai, Mahito; Kashiwaya, Tagui; Atoh, Keita; Making, Isao (2003). "Early Detection of Orthostatic Hypotension by Quantitative Sudomotor Axon Reflex Test (QSART) in Type 2 Diabetic Patients". Internal Medicine. 42 (7): 560–564. doi:10.2169/internalmedicine.42.560. PMID 12879946. Yajnik, C.S.; Kantikar, V.; Pande, A.; Deslypere, J.-P.; Dupin, J.; Calvet, J.-H.; Bauduceau, B. (April 2013). "Screening of cardiovascular autonomic neuropathy in patients with diabetes using non-invasive quick and simple assessment of sudomotor function". Diabetes & Metabolism. 39 (2): 126–131. doi:10.1016/j.diabet.2012.09.004. PMID 23159130. Gerrett, Nicola; Griggs, Katy; Redortier, Bernard; Voelcker, Thomas; Kondo, Narihiko; Havenith, George (1 August 2018). "Sweat from gland to skin surface: production, transport, and skin absorption" (PDF). Journal of Applied Physiology. 125 (2): 459–469. doi:10.1152/japplphysiol.00872.2017. PMID 29745799. S2CID 13675424. Quinton, Paul M. (June 2007). "Cystic Fibrosis: Lessons from the Sweat Gland". Physiology. 22 (3): 212–225. doi:10.1152/physiol.00041.2006. PMID 17557942. Gibbons, Christopher H; Wang, Ningshan; Freeman, Roy (December 2010). "Capsaicin Induces Degeneration of Cutaneous Autonomic Nerve Fibers". Annals of


id: suicide-terminology-20260505-0
file: data/en.wikipedia.org/wiki/Suicide_terminology-0.md
category: reference
title: Suicide terminology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Suicide_terminology
date_saved: 2026-05-05T07:33:39.761747+00:00
instance: kb-cron
parent: suicide-terminology-20260505-0
summary:
Historically, suicide terminology has been rife with issues of nomenclature, connotation, and outcomes, and terminology describing suicide has often been defined differently depending on the purpose of the definition (e.g., medical, legal, administrative). A lack of agreed-upon nomenclature and operational definitions has complicated understanding. In 2007, attempts were made to reach some consensus. There is controversy regarding the phrase "to commit suicide" as some view it as implying negative moral judgment and having an association with criminal or sinful activity. In 2020, a meta-analysis of studies on the effects of media coverage of suicide found that "Reporting of deaths of celebrities by suicide appears to increase the number of suicides by 8-18% in the next 1-2 months, and information on method of suicide was associated with an increase of 18-44% in the risk of suicide by the same method." == Terminology == === Origin === The word suicide (latin: suicidio) was coined by the Spanish cistercian monk Juan Caramuel in their work Theologia moralis fundamentalis of 1652 === Ideations === Suicidal ideation is any self-reported thoughts of engaging in suicide-related behavior. Subtypes of suicide-related ideations depend on the presence or absence of suicidal intent. To have suicidal intent is to


id: suicide-terminology-20260505-1
file: data/en.wikipedia.org/wiki/Suicide_terminology-1.md
category: reference
title: Suicide terminology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Suicide_terminology
date_saved: 2026-05-05T07:33:39.761747+00:00
instance: kb-cron
parent: suicide-terminology-20260505-0
summary:
== "Committing" suicide == According to Fairbairn in his philosophical study of suicide published in 1995, "The most common way of speaking about suicide is to talk of its being 'committed'." An article published in 2011 stated that, although committed suicide or similar descriptions continued to be the norm in the English language, the term committed associates death by suicide, or more accurately, death by mental illness, with criminal or sinful actions. Research has pointed out that this phrasing has become so entrenched in English vocabulary that it has gained "a naturalness which implies a deceptive harmlessness." Per reportingonsuicide.org,Certain phrases and words can further stigmatize suicide, spread myths, and undermine suicide prevention objectives such as "committed suicide" or referring to suicide as "successful," "unsuccessful" or a "failed attempt." Instead use, "died by suicide" or "killed him/herself." While common, Lebacqz & Englehardt argue that referring to suicide as an act "committed" is hazardous to ethical clarity. Others have also argued in favour of alternative language regarding suicide, both in the interest of moral and ethical precision, as well as scientific and clinical clarity. A United States Navy report urges against the use of the term committed suicide on similar grounds, asserting


id: surgical-sieve-20260505-0
file: data/en.wikipedia.org/wiki/Surgical_sieve-0.md
category: reference
title: Surgical sieve
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Surgical_sieve
date_saved: 2026-05-05T07:33:40.958811+00:00
instance: kb-cron
parent: surgical-sieve-20260505-0
summary:
The surgical sieve is a thought process in medicine. It is a typical example of how to organise a structured examination answer for medical students and physicians when they are challenged with a question. It is also a way of constructing answers to questions from patients and their relatives in a logical manner, and structuring articles and reference texts in medicine. Some textbooks put emphasis on using the surgical sieve as a basic structure of diagnosis and management of illnesses. == Overview == Although there are several versions around the world with slight variations, the surgical sieve usually consist of the following types of process in the human body in any particular order: Congenital Acquired Vascular Infective Traumatic Autoimmune Metabolic Inflammatory Neurological Neoplastic Degenerative Environmental Unknown A more extensive, and perhaps more concise mechanism of employing the surgical sieve is using the mnemonic MEDIC HAT PINE: Metabolic (conditions relating to metabolism, biochemistry, and the like) Endocrinological (conditions relating to the various secretory systems within the body) Degenerative (conditions relating to age-related destruction of tissue, or stress-related destruction of tissue) Inflammatory/Infective (conditions that primarily present in a way that involves the profane activation of the immune system) Congenital (conditions present at


id: surgical-smoke-20260505-0
file: data/en.wikipedia.org/wiki/Surgical_smoke-0.md
category: reference
title: Surgical smoke
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Surgical_smoke
date_saved: 2026-05-05T07:33:42.265114+00:00
instance: kb-cron
parent: surgical-smoke-20260505-0
summary:
Surgical smoke is the by-product produced by electrosurgery, laser tissue ablation, or other surgical techniques. Surgical smoke, as a health threat to those exposed to it, has become a growing concern. Studies have demonstrated, depending on several factors, it may contain carcinogens, mutagens, irritant chemicals, live viruses and bacteria, and viable malignant cells. These all pose a theoretical and demonstrable risk of harming patients or operating room personnel upon exposure. Other names for surgical smoke are cautery smoke, plume, diathermy plume, or, sometimes, aerosols produced during surgery, vapor contaminants, or air contaminants. Electrosurgery and laser ablation are the most common sources of surgical smoke. Heat generated during surgery causes cell membranes to heat and rupture, releasing cellular debris alongside water vapor. Surgical smoke is composed of 95% water and the remaining 5% contains byproducts of combustion and cellular debris. The negative health effects due to exposure of surgical smoke is attributed to what is contained in the 5%. The size of particles within the plume of smoke varies depending on the device that generated it. On average electrosurgery produces particles that are .07 μm, while laser ablation generates larger particles that are .31 μm on average. Particles smaller than 2


id: surrogate-decision-maker-20260505-0
file: data/en.wikipedia.org/wiki/Surrogate_decision-maker-0.md
category: reference
title: Surrogate decision-maker
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Surrogate_decision-maker
date_saved: 2026-05-05T07:33:43.576285+00:00
instance: kb-cron
parent: surrogate-decision-maker-20260505-0
summary:
A surrogate decision maker, also known as a health care proxy or as agents, is an advocate for incompetent patients. If a patient is unable to make decisions for themselves about personal care, a surrogate agent must make decisions for them. If there is a durable power of attorney for health care, the agent appointed by that document is authorized to make health care decisions within the scope of authority granted by the document. If people have court-appointed guardians with authority to make health care decisions, the guardian is the authorized surrogate. == Background == At the 1991 Annual Meeting of the American Medical Association, the AMA adopted the report of the Council on Ethical and Judicial Affairs known as, "Decisions to Forgo Life-Sustaining Treatment for Incompetent Patients." The recommendations of the report were the basis for amendments to Opinion 2.20 known as, "Withholding or Withdrawing Life-Sustaining Medical Treatment." The report itself provides guidelines for physicians who may have to identify a surrogate decision maker, assist a surrogate (proxy) in making decisions for incompetent patients, and resolve conflicts that may arise between decision makers, or between the decision maker's choice and medically appropriate options. Since the first incorporation of these


id: surrogate-decision-maker-20260505-1
file: data/en.wikipedia.org/wiki/Surrogate_decision-maker-1.md
category: reference
title: Surrogate decision-maker
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Surrogate_decision-maker
date_saved: 2026-05-05T07:33:43.576285+00:00
instance: kb-cron
parent: surrogate-decision-maker-20260505-0
summary:
== Criteria for being a surrogate agent == In the event that a surrogate decision maker has not been identified through either a medical power of attorney or a court-appointed legal guardian, such an agent is selected by medical personnel. A patient must meet a certain set of criteria prior to the legal selection of a health care surrogate agent. The patient must have a disabling condition such as a mental illness or infirmity, an impairment in the ability to complete activities of daily living, cognitive impairment, and a lack of any previously indicated alternative to guardianship. This person is chosen by either the attending physician or their advance practice nurse. In the US, hierarchy of health care surrogates may vary according to the law of the specific state, but an example order of priority is listed here: The client's guardian The client's spouse Any adult son or daughter of the client Either parent of the client Any adult brother or sister of the client Any adult grandchild of the client, or an adult relative who has exhibited special care and concern, who has maintained close contact, and who is familiar with the patient's activities, health, and religious or moral


id: surrogate-decision-maker-20260505-2
file: data/en.wikipedia.org/wiki/Surrogate_decision-maker-2.md
category: reference
title: Surrogate decision-maker
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Surrogate_decision-maker
date_saved: 2026-05-05T07:33:43.576285+00:00
instance: kb-cron
parent: surrogate-decision-maker-20260505-0
summary:
=== Current status of the law === Adults that are considered competent have the right to refuse treatment. As stated above, some states allow incompetent adults to refuse treatment. There can also be recommended termination of medical treatment for incompetent adults by a physician. Two tests for competency are the substituted judgment test and the best interests test. Current statutory solutions include living wills or advance directives that explain the patient's wishes in certain medical situations. A durable power of attorney for health care (DPA/HC) and is another way of identifying a patient's final wishes through an attorney. The patient self-determination act states that hospitals and health care facilities must provide information about advance directives and DPA/HC. Also, a proxy or surrogate decision-maker can provide these final wishes to the doctor or care team if a DPA/HC or AD is not present. Some fictional assumptions underlying judicial decisions include the following misconceptions: 1. It is better to make a mistake in favor of preserving the patient's life. This is an all too common misconception about surrogate decision-making, and another reason why it is so important to have a DPA/HC or AD. In most cases, patients wish to have a death


id: surrogate-endpoint-20260505-0
file: data/en.wikipedia.org/wiki/Surrogate_endpoint-0.md
category: reference
title: Surrogate endpoint
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Surrogate_endpoint
date_saved: 2026-05-05T07:33:44.845084+00:00
instance: kb-cron
parent: surrogate-endpoint-20260505-0
summary:
In clinical trials, a surrogate endpoint (or surrogate marker) is a measure of effect of a specific treatment that may correlate with a real clinical endpoint but does not necessarily have a guaranteed relationship. The National Institutes of Health (USA) defines surrogate endpoint as "a biomarker intended to substitute for a clinical endpoint". Surrogate markers are used when the primary endpoint is undesired (e.g., death), or when the number of events is very small, thus making it impractical to conduct a clinical trial to gather a statistically significant number of endpoints. The FDA and other regulatory agencies will often accept evidence from clinical trials that show a direct clinical benefit to surrogate markers. Surrogate endpoints can be obtained from different modalities, such as, behavioural or cognitive scores, or biomarkers from Electroencephalography (qEEG), MRI, PET, or biochemical biomarkers. A correlate does not make a surrogate. It is a common misconception that if an outcome is a correlate (that is, correlated with the true clinical outcome) it can be used as a valid surrogate endpoint (that is, a replacement for the true clinical outcome). However, proper justification for such replacement requires that the effect of the intervention on the surrogate endpoint predicts


id: symptomatic-treatment-20260505-0
file: data/en.wikipedia.org/wiki/Symptomatic_treatment-0.md
category: reference
title: Symptomatic treatment
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Symptomatic_treatment
date_saved: 2026-05-05T07:33:46.188794+00:00
instance: kb-cron
parent: symptomatic-treatment-20260505-0
summary:
Symptomatic treatment, supportive care, supportive therapy, or palliative treatment is any medical therapy of a disease that only affects its symptoms, not the underlying cause. It is usually aimed at reducing the signs and symptoms for the comfort and well-being of the patient, but it also may be useful in reducing organic consequences and sequelae of these signs and symptoms of the disease. In many diseases, even in those whose etiologies are known (e.g., most viral diseases, such as influenza and Rift Valley fever), symptomatic treatment is the only treatment available so far. For more detail, see supportive therapy. For conditions like cancer, arthritis, neuropathy, tendinopathy, and injury, it can be useful to distinguish treatments that are supportive/palliative and cannot alter the natural history of the disease (disease modifying treatments). == Examples == Examples of symptomatic treatments: Analgesics, to reduce pain Anti-inflammatory agents, for inflammation caused by arthritis Antitussives, for cough Antihistaminics (also known as antihistamines), for allergy Antipyretics, for fever Enemas for constipation Treatments that reduce unwanted side effects from drugs == Uses == When the etiology (the cause, set of causes, or manner of causation of a disease or condition) for the disease is known, then specific treatment


id: syndrome-20260505-0
file: data/en.wikipedia.org/wiki/Syndrome-0.md
category: reference
title: Syndrome
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Syndrome
date_saved: 2026-05-05T07:33:47.470965+00:00
instance: kb-cron
parent: syndrome-20260505-0
summary:
A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". When a syndrome is paired with a definite cause this becomes a disease. In some instances, a syndrome is so closely linked with a pathogenesis or cause that the words syndrome, disease, and disorder end up being used interchangeably for them. This substitution of terminology often confuses the reality and meaning of medical diagnoses. This is especially true of inherited syndromes. About one third of all phenotypes that are listed in OMIM are described as dysmorphic, which usually refers to the facial gestalt. For example, Down syndrome, Wolf–Hirschhorn syndrome, and Andersen–Tawil syndrome are disorders with known pathogeneses, so each is more than just a set of signs and symptoms, despite the syndrome nomenclature. In other instances, a syndrome is not specific to only one disease. For example, toxic shock syndrome can be caused by various toxins; another medical syndrome named as premotor syndrome can be caused by various brain lesions; and premenstrual syndrome is not a disease but simply a set of symptoms. If an underlying


id: syndrome-20260505-1
file: data/en.wikipedia.org/wiki/Syndrome-1.md
category: reference
title: Syndrome
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Syndrome
date_saved: 2026-05-05T07:33:47.470965+00:00
instance: kb-cron
parent: syndrome-20260505-0
summary:
=== Other fields === In biology, "syndrome" is used in a more general sense to describe characteristic sets of features in various contexts. Examples include behavioral syndromes, as well as pollination syndromes and seed dispersal syndromes. In orbital mechanics and astronomy, Kessler syndrome refers to the effect where the density of objects in low Earth orbit (LEO) is high enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions. In quantum error correction theory syndromes correspond to errors in code words which are determined with syndrome measurements, which only collapse the state on an error state, so that the error can be corrected without affecting the quantum information stored in the code words. == Naming == There is no set common convention for the naming of newly identified syndromes. In the past, syndromes were often named after the physician or scientist who identified and described the condition in an initial publication. These are referred to as "eponymous syndromes". In some cases, diseases are named after the patient who initially presents with symptoms, or their home town (Stockholm syndrome). There have been isolated cases of patients being eager


id: systemic-disease-20260505-0
file: data/en.wikipedia.org/wiki/Systemic_disease-0.md
category: reference
title: Systemic disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Systemic_disease
date_saved: 2026-05-05T07:33:48.676564+00:00
instance: kb-cron
parent: systemic-disease-20260505-0
summary:
A systemic disease is one that affects a number of organs and tissues, or affects the body as a whole. It differs from a localized disease, which is a disease affecting only part of the body (e.g., a mouth ulcer). == Examples == Mastocytosis, including mast cell activation syndrome and eosinophilic esophagitis Chronic fatigue syndrome Systemic vasculitis e.g. SLE, PAN Sarcoidosis – a disease that mainly affects the lungs, brain, joints and eyes, found most often in young African-American women. Hypothyroidism – where the thyroid gland produces too little thyroid hormones. Diabetes mellitus – an imbalance in blood glucose (sugar) levels. Fibromyalgia Ehlers-Danlos syndromes - an inherited connective tissue disorder with multiple subcategories Adrenal insufficiency – where the adrenal glands don't produce enough steroid hormones Coeliac disease – an autoimmune disease triggered by gluten consumption, which may involve several organs and cause a variety of symptoms, or be completely asymptomatic. Ulcerative colitis – an inflammatory bowel disease Crohn's disease – an inflammatory bowel disease Hypertension (high blood pressure) Metabolic syndrome AIDS – a disease caused by a virus that cripples the body's immune defenses. Graves' disease – a thyroid disorder, most often in women, which can cause a goiter (swelling


id: terminal-cleaning-20260505-0
file: data/en.wikipedia.org/wiki/Terminal_cleaning-0.md
category: reference
title: Terminal cleaning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminal_cleaning
date_saved: 2026-05-05T07:33:49.838595+00:00
instance: kb-cron
parent: terminal-cleaning-20260505-0
summary:
Terminal cleaning is the thorough cleaning of a room after use, used in healthcare environments to control the spread of infections. == Justification == Nosocomial infections claim approximately 90,000 lives in the United States annually. When patients are hospitalized and identified as having methicillin-resistant Staphylococcus aureus or infections that can be spread to other patients, best practices isolate these patients in rooms that are subjected to terminal cleaning when the patient is discharged. For example, terminal cleaning reduces the spread of C. difficile infections. == Procedure == Terminal cleaning requires cleaning the entire room after use by the patient. Methods vary, but involve disinfection of all surfaces and discarding all disposable items and cleaning rags or towels as medical waste. == See also == Nosocomial infection MRSA VRE Pseudomonas aeruginosa == References == == Further reading == Environmental Cleaning Procedures Reinigungsmittel (in German)


id: terminal-illness-20260505-0
file: data/en.wikipedia.org/wiki/Terminal_illness-0.md
category: reference
title: Terminal illness
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminal_illness
date_saved: 2026-05-05T07:33:51.114989+00:00
instance: kb-cron
parent: terminal-illness-20260505-0
summary:
Terminal illness or end-stage disease is a disease that cannot be cured, or adequately treated, and typically results in the death of the patient. This term is usually used for progressive diseases such as cancer, rather than fatal injury. In popular use, it indicates a disease that will progress until death with near absolute certainty, regardless of treatment. A patient who has such an illness may be referred to as a terminal patient, terminally ill or simply as being terminal. There is no standardized life expectancy for a patient to be considered terminal, although it is generally months or less. An illness which will result in premature death, even if that death may be many years away, is called a life-limiting illness. An illness which is lifelong but not life-shortening is called a chronic condition. Terminal patients usually have options for disease management after diagnosis; examples may include caregiving, continued treatment, palliative and hospice care, and physician-assisted suicide. Decisions regarding management are made by the patient and their family, although medical professionals may offer recommendations of services available to terminal patients. Lifestyle after diagnosis varies depending on management decisions and the nature of the disease, and there may be restrictions


id: terminal-illness-20260505-1
file: data/en.wikipedia.org/wiki/Terminal_illness-1.md
category: reference
title: Terminal illness
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminal_illness
date_saved: 2026-05-05T07:33:51.114989+00:00
instance: kb-cron
parent: terminal-illness-20260505-0
summary:
=== Caregiving === Terminal patients often need a caregiver, who could be a nurse, licensed practical nurse or a family member. Caregivers can help patients receive medications to reduce pain and control symptoms of nausea or vomiting. They can also assist the individual with daily living activities and movement. Caregivers provide assistance with food and psychological support and ensure that the individual is comfortable. The patient's family may have questions and most caregivers can provide information to help ease the mind. Doctors generally do not provide estimates for fear of instilling false hopes or obliterate an individual's hope. In most cases, the caregiver works along with physicians and follows professional instructions. Caregivers may call the physician or a nurse if the individual: experiences excessive pain. is in distress or having difficulty breathing. has difficulty passing urine or is constipated. has fallen and appears hurt. is depressed and wants to harm themselves. refuses to take prescribed medications, raising ethical concerns best addressed by a person with more extensive formal training. or if the caregiver does not know how to handle the situation. Most caregivers become the patient's listeners and let the individual express fears and concerns without judgment. Caregivers reassure the


id: terminal-illness-20260505-2
file: data/en.wikipedia.org/wiki/Terminal_illness-2.md
category: reference
title: Terminal illness
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminal_illness
date_saved: 2026-05-05T07:33:51.114989+00:00
instance: kb-cron
parent: terminal-illness-20260505-0
summary:
=== Physician-assisted suicide === Physician-assisted suicide (PAS) is highly controversial, and legal in only a few countries. In PAS, physicians, with voluntary written and verbal consent from the patient, give patients the means to die, usually through lethal drugs. The patient decides on their own time and place to die. Reasons as to why patients choose PAS differ. Factors that may play into a patient's decision include future disability and suffering, lack of control over death, impact on family, healthcare costs, insurance coverage, personal beliefs, religious beliefs, and much more. PAS may be referred to in many different ways, such as aid in dying, assisted dying, death with dignity, and many more. These often depend on the organization and the stance they take on the issue. In this section of the article, it will be referred to as PAS for the sake of consistency with the pre-existing Wikipedia page: Assisted Suicide. In the United States, PAS or medical aid in dying is legal in select states, including Oregon, Washington, Montana, Vermont, and New Mexico, and there are groups both in favor of and against legalization. Some groups favor PAS because they do not believe they will have control over their


id: terminal-illness-20260505-3
file: data/en.wikipedia.org/wiki/Terminal_illness-3.md
category: reference
title: Terminal illness
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminal_illness
date_saved: 2026-05-05T07:33:51.114989+00:00
instance: kb-cron
parent: terminal-illness-20260505-0
summary:
=== Mortality predictions === Often, a patient is considered terminally ill when their estimated life expectancy is six months or less, under the assumption that the disease will run its normal course based on previous data from other patients. The six-month standard is arbitrary, and best available estimates of longevity may be incorrect. Though a given patient may properly be considered terminal, this is not a guarantee that the patient will die within six months. Similarly, a patient with a slowly progressing disease, such as AIDS, may not be considered terminally ill if the best estimate of longevity is greater than six months. However, this does not guarantee that the patient will not die unexpectedly early. In general, physicians slightly overestimate the survival time of terminally ill cancer patients, so that, for example, a person who is expected to live for about six weeks would likely die around four weeks. A recent systematic review on palliative patients in general, rather than specifically cancer patients, states the following: "Accuracy of categorical estimates in this systematic review ranged from 23% up to 78% and continuous estimates over-predicted actual survival by, potentially, a factor of two." There was no evidence that any specific


id: terminal-illness-20260505-4
file: data/en.wikipedia.org/wiki/Terminal_illness-4.md
category: reference
title: Terminal illness
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminal_illness
date_saved: 2026-05-05T07:33:51.114989+00:00
instance: kb-cron
parent: terminal-illness-20260505-0
summary:
== Death == When dying, patients often worry about their quality of life towards the end, including emotional and physical suffering. In order for families and doctors to understand clearly what the patient wants for themselves, it is recommended that patients, doctors, and families all convene and discuss the patient's decisions before the patient becomes unable to decide. === Advance directives === At the end of life, especially when patients are unable to make decisions on their own regarding treatment, it is often up to family members and doctors to decide what they believe the patients would have wanted regarding their deaths, which is often a heavy burden and hard for family members to predict. An estimated 25% of American adults have an advance directive, meaning the majority of Americans leave these decisions to be made by family, which can lead to conflict and guilt. Although it may be a difficult subject to broach, it is important to discuss the patient's plans for how far to continue treatment should they become unable to decide. This must be done while the patient is still able to make the decisions, and takes the form of an advance directive. The advance directive should


id: testicular-microlithiasis-20260505-0
file: data/en.wikipedia.org/wiki/Testicular_microlithiasis-0.md
category: reference
title: Testicular microlithiasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Testicular_microlithiasis
date_saved: 2026-05-05T07:33:52.388808+00:00
instance: kb-cron
parent: testicular-microlithiasis-20260505-0
summary:
Testicular microlithiasis is an unusual condition diagnosed on testicular ultrasound. It is believed to be found in 0.1–0.5% of males globally, with frequency varying based on geographic location and is more often found in individuals with subfertility. It is often an asymptomatic, non-progressive disease; though in a very small number of cases it may also cause bouts of extreme chronic fatigue, hormone imbalance and pain, which can be severe and accompanied by swelling around the testicular region (dependent on the size and location of the calcification). In an extremely rare select few cases, individuals with microlithiasis have also been known to experience calcification of the prostate, which can lead to the passing of stones. These rare cases can lead to secondary infections if not treated with care, due to the resulting damaged tissue. However, these symptoms are rarely seen in the majority of people who have been diagnosed. Testicular microlithiasis is not associated with risk of testicular cancer in asymptomatic individuals, except in individuals who experience symptoms. However, a large meta-analysis has shown that in individuals with associated risk factors for testicular germ cell tumor, the increase in risk of concurrent diagnosis of testicular germ cell tumor, or testicular carcinoma-in-situ


id: therapeutic-inertia-20260505-0
file: data/en.wikipedia.org/wiki/Therapeutic_inertia-0.md
category: reference
title: Therapeutic inertia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Therapeutic_inertia
date_saved: 2026-05-05T07:33:53.692796+00:00
instance: kb-cron
parent: therapeutic-inertia-20260505-0
summary:
Therapeutic inertia (also known as clinical inertia) is a measurement of the resistance to therapeutic treatment for an existing medical condition. It is commonly measured as a percentage of the number of encounters in which a patient with a condition received new or increased therapeutic treatment out of the total number of visits to a health care professional by the patient. A high percentage indicates that the health care provider is slow to treat a medical condition. A low percentage indicates that a provider is extremely quick in prescribing new treatment at the onset of any medical condition. == Calculation == There are two common methods used in calculating therapeutic inertia. For the following examples, consider that a patient has five visits with a health provider. In four of those visits, a condition is not controlled (such as high blood pressure or high cholesterol). In two of those visits, the provider made a change to the patient's treatment for the condition. In Dr. Okonofua's original paper, this patient's therapeutic inertia is calculated as h v − c v {\displaystyle {\frac {h}{v}}-{\frac {c}{v}}} where h is the number of visits with an uncontrolled condition, c is the number of visits in


id: topical-medication-20260505-0
file: data/en.wikipedia.org/wiki/Topical_medication-0.md
category: reference
title: Topical medication
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Topical_medication
date_saved: 2026-05-05T07:33:54.857316+00:00
instance: kb-cron
parent: topical-medication-20260505-0
summary:
A topical medication is a medication that is applied to a particular place on or in the body. Most often, topical medications are applied to the skin or mucous membranes, via creams, foams, gels, lotions, or ointments. Many topical medications are epicutaneous, meaning that they are applied directly to the skin. Topical medications may also be inhalational, such as asthma medications, or applied to the surface of tissues other than the skin, such as eye drops applied to the conjunctiva, or ear drops placed in the ear, or medications applied to the surface of a tooth. The word topical derives from Greek τοπικός topikos, "of a place". == Justification == Topical drug delivery is a route of administering drugs via the skin to provide topical therapeutic effects. As skin is one of the largest and most superficial organs in the human body, pharmacists utilise it to deliver various drugs. This system usually provides a local effect on certain positions of the body. In ancient times, people used herbs to put on wounds for relieving the inflammatory effect or as pain relievers. The use of topical drug delivery system is much broader now, from smoking cessation to beauty purposes. Nowadays, there


id: topical-medication-20260505-1
file: data/en.wikipedia.org/wiki/Topical_medication-1.md
category: reference
title: Topical medication
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Topical_medication
date_saved: 2026-05-05T07:33:54.857316+00:00
instance: kb-cron
parent: topical-medication-20260505-0
summary:
== Choice of base formulation == A medication's potency often is changed with its base. For example, some topical steroids will be classified one or two strengths higher when moving from cream to ointment. As a rule of thumb, an ointment base is more occlusive and will drive the medication into the skin more rapidly than a solution or cream base. The manufacturer of each topical product has total control over the content of the base of a medication. Although containing the same active ingredients, one manufacturer's cream might be more acidic than the next, which could cause skin irritation or change its absorption rate. For example, a vaginal formulation of miconazole antifungal cream might irritate the skin less than an athlete's foot formulation of miconazole cream. These variations can, on occasion, result in different clinical outcomes, even though the active ingredient is the same. No comparative potency labeling exists to ensure equal efficacy between brands of topical steroids (percentage of oil vs water dramatically affect the potency of topical steroid). Studies have confirmed that the potency of some topical steroid products may differ according to manufacturer or brand. An example of this is the case of brand name Valisone


id: topical-medication-20260505-2
file: data/en.wikipedia.org/wiki/Topical_medication-2.md
category: reference
title: Topical medication
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Topical_medication
date_saved: 2026-05-05T07:33:54.857316+00:00
instance: kb-cron
parent: topical-medication-20260505-0
summary:
Absorption bases, e.g., beeswax and wool fat Emulsifying bases, e.g., cetrimide and emulsifying wax Hydrocarbon bases, e.g., ceresine, microcrystalline wax, hard paraffin, and soft paraffin Vegetable oil bases, e.g., almond oil, coconut oil, olive oil, peanut oil, and sesame oil Water-soluble bases, e.g., macrogols 200, 300, 400 The medicaments are dispersed in the base and are divided after penetrating the living cells of the skin. The water number of an ointment is the maximum quantity of water that 100g of a base can contain at 20 °C. Ointments are formulated using hydrophobic, hydrophilic, or water-emulsifying bases to provide preparations that are immiscible, miscible, or emulsifiable with skin secretions. They can also be derived from hydrocarbon (fatty), absorption, water-removable, or water-soluble bases. Evaluation of ointments: Drug content Release of medicament from base Medicament penetration Consistency of the preparation Absorption of medicament into blood stream Irritant effect Properties which affect choice of an ointment base are: Stability Penetrability Solvent property Irritant effects Ease of application and removal Methods of preparation of ointments: Fusion: In this method the ingredients are melted together in descending order of their melting points and stirred to ensure homogeneity. Trituration: In this finely subdivided insoluble medicaments are evenly


id: topical-medication-20260505-3
file: data/en.wikipedia.org/wiki/Topical_medication-3.md
category: reference
title: Topical medication
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Topical_medication
date_saved: 2026-05-05T07:33:54.857316+00:00
instance: kb-cron
parent: topical-medication-20260505-0
summary:
=== Advantages of topical drug delivery systems === In the early 1970s, the Alza Corporation, through their founder Alejandro Zaffaroni, filed the first US patents describing transdermal delivery systems for scopolamine, nitroglycerin and nicotine. People found that applying medicines on the body surfaces is beneficial in many aspects. Skin medicines can give faster onset and local effect on our body as the surface cream can bypass first pass metabolism such as hepatic and intestinal metabolism. Apart from the absorption, dermal drugs effectively prevent oral delivery limitations such as nausea and vomiting and poor appliances due to unpalatable tastes of the drugs . Topical application is an easy way for patients to tackle skin infections in a painless and non-invasive way. From a patient perspective, applying drugs on skin also provides stable dosage in blood so as to give the optimal bioavailability and therapeutic effects. In case of overdose or unwanted side effects, patients can take off or wash out the medicines quickly to eliminate toxicity by simply removing the patch to stop the delivery of drugs. === Disadvantages of topical drug delivery systems === The site of putting the patches for topical drugs may get irritated and have rashes and


id: toxidrome-20260505-0
file: data/en.wikipedia.org/wiki/Toxidrome-0.md
category: reference
title: Toxidrome
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Toxidrome
date_saved: 2026-05-05T07:33:56.103303+00:00
instance: kb-cron
parent: toxidrome-20260505-0
summary:
A toxidrome (a portmanteau of toxic and syndrome, coined in 1970 by Mofenson and Greensher) is a syndrome caused by a dangerous level of a toxin in the body. It is often the consequence of a drug overdose. Common symptoms include dizziness, disorientation, nausea, vomiting and oscillopsia. It may indicate a medical emergency requiring treatment at a poison control center. Aside from poisoning, a systemic infection may also lead to one. Classic toxidromes may be variable or obscured by co-ingestion of multiple drugs. A common tool for assessing for the presence of toxidrome in the United Kingdom is the CRESS tool. == Anticholinergic == The symptoms of an anticholinergic toxidrome include blurred vision, coma, decreased bowel sounds, delirium, dry skin, fever, flushing, hallucinations, ileus, memory loss, mydriasis (dilated pupils), myoclonus, psychosis, seizures and urinary retention. Complications include hypertension, hyperthermia and tachycardia. Substances that may cause this toxidrome include antihistamines, antipsychotics, antidepressants, antiparkinsonian drugs, atropine, benztropine, datura, diphenhydramine and scopolamine. == Cholinergic == The symptoms of a cholinergic toxidrome include bronchorrhea, confusion, defecation, diaphoresis, diarrhea, emesis, lacrimation, miosis, muscle fasciculations, salivation, seizures, urination and weakness. Complications include bradycardia, hypothermia and tachypnea. Substances that may cause this toxidrome include carbamates, mushrooms and


id: trojan-horse-effect-20260505-0
file: data/en.wikipedia.org/wiki/Trojan_Horse_effect-0.md
category: reference
title: Trojan Horse effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Trojan_Horse_effect
date_saved: 2026-05-05T07:33:57.370355+00:00
instance: kb-cron
parent: trojan-horse-effect-20260505-0
summary:
The Trojan Horse effect is a term used in scientific literature, referring to substances that act as carriers for other compounds, facilitating their transport. == Definition and examples == The effect generally refers to substance that facilitate the diffusion of other compounds. An example of this concept is observed with microplastics which act as carriers of organic compounds to new sites in the environment via sorption and desorption. == Medicine == It is also utilized in the field of medicine, for example to allow for the administration of medicine across the blood–brain barrier via lipid nanoparticles. The Trojan Horse effect is utilized by some antibiotics. By having the active compound bound to a mimic compound of molecules which are desirable to the bacteria. == References ==


id: ureterovaginal-fistula-20260505-0
file: data/en.wikipedia.org/wiki/Ureterovaginal_fistula-0.md
category: reference
title: Ureterovaginal fistula
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ureterovaginal_fistula
date_saved: 2026-05-05T07:33:58.574628+00:00
instance: kb-cron
parent: ureterovaginal-fistula-20260505-0
summary:
A ureterovaginal fistula is an abnormal passageway existing between the ureter and the vagina. It presents as urinary incontinence. Its impact on women is to reduce the "quality of life dramatically." == Cause == A ureterovaginal fistula is a result of trauma, infection, pelvic surgery, radiation treatment and therapy, malignancy, or inflammatory bowel disease. Symptoms can be troubling for women especially since some clinicians delay treatment until inflammation is reduced and stronger tissue has formed. The fistula may develop as a maternal birth injury from a long and protracted labor, long dilation time and expulsion period. Difficult deliveries can create pressure necrosis in the tissue that is being pushed between the head of the infant and the softer tissues of the vagina, ureters, and bladder. Radiographic imaging can assist clinicians in identifying the abnormality. A Ureterovaginal fistula is always indicative of an obstructed kidney necessitating emergency intervention followed later by an elective surgical repair of the fistula. == Treatment == Many women delay treatment for decades. Surgeons often will correct the fistula through major gynecological surgery. Newer treatments can include the placement of a stent and is usually successful. In 0.5-2.5% of major pelvic surgeries a ureterovaginal fistula will form,


id: va-conduction-20260505-0
file: data/en.wikipedia.org/wiki/VA_conduction-0.md
category: reference
title: VA conduction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/VA_conduction
date_saved: 2026-05-05T07:33:59.807665+00:00
instance: kb-cron
parent: va-conduction-20260505-0
summary:
VA conduction, also named Ventriculoatrial conduction and sometimes referred to as Retrograde conduction, is the conduction backward phenomena in the heart, where the conduction comes from the ventricles or from the AV node into and through the atria. Retrograde VA conduction results in many different symptoms, primarily those symptoms result from the delayed, nonphysiologic timing of atrial contraction in relation to ventricular contraction. == References ==


id: vascular-occlusion-20260505-0
file: data/en.wikipedia.org/wiki/Vascular_occlusion-0.md
category: reference
title: Vascular occlusion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Vascular_occlusion
date_saved: 2026-05-05T07:34:01.129462+00:00
instance: kb-cron
parent: vascular-occlusion-20260505-0
summary:
Vascular occlusion is a blockage of a blood vessel, usually with a clot. It differs from thrombosis in describing any form of blockage, not just one formed by a clot. When it occurs in a major vein, it can, in some cases, cause deep vein thrombosis. The condition is also relatively common in the retina, and can cause partial or total loss of vision. An occlusion can often be diagnosed using Doppler sonography (a form of ultrasound). Some medical procedures, such as embolisation, involve occluding a blood vessel to treat a particular condition. This can be to reduce pressure on aneurysms (weakened blood vessels) or to restrict a haemorrhage. It can also be used to reduce blood supply to tumours or growths in the body, and therefore restrict their development. Occlusion can be carried out using a ligature; by implanting small coils which stimulate the formation of clots; or, particularly in the case of cerebral aneurysms, by clipping. == See also == Central retinal artery occlusion Central retinal vein occlusion Branch retinal artery occlusion Branch retinal vein occlusion == References ==


id: vasomotor-20260505-0
file: data/en.wikipedia.org/wiki/Vasomotor-0.md
category: reference
title: Vasomotor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Vasomotor
date_saved: 2026-05-05T07:34:02.324637+00:00
instance: kb-cron
parent: vasomotor-20260505-0
summary:
Vasomotor refers to actions upon a blood vessel which alter its diameter. More specifically, it can refer to vasodilator action and vasoconstrictor action. == Control == === Sympathetic innervation === Sympathetic nerve fibers travel around the tunica media of the artery, secrete neurotransmitters such as norepinephrine into the extracellular fluid surrounding the smooth muscle (tunica media) from the terminal knob of the axon. The smooth muscle cell membranes have α and β-adrenergic receptors for these neurotransmitters. Activation of α-adrenergic receptors promotes vasoconstriction, while the activation of β-adrenergic receptors mediates the relaxation of muscle cells, resulting in vasodilation. Normally, α-adrenergic receptors predominate in smooth muscle of resistance vessels. === Endothelium derived chemicals === Endothelin, and angiotensin are the vasoconstrictors of smooth muscles while nitric oxide and prostacyclin are vasodilators of the smooth muscles. == Pathology == Some vasoactive chemicals such as vasodilator acetylcholine are known for causing reduced/increased blood flow in the tumours by vasomotor changes. Inadequate blood supply to the tumour cells can cause the cells to be radio-resistant and resulted in reduced accessibility to chemotherapeutic agents. Injuries to nerves of the lower trunk of the brachial plexus (Klumpke's paralysis) and compression of median nerve at the flexor retinaculum of


id: vegetation-pathology-20260505-0
file: data/en.wikipedia.org/wiki/Vegetation_(pathology)-0.md
category: reference
title: Vegetation (pathology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Vegetation_(pathology)
date_saved: 2026-05-05T07:34:03.543730+00:00
instance: kb-cron
parent: vegetation-pathology-20260505-0
summary:
In medicine, a vegetation is an abnormal growth named for its similarity to natural vegetation. Vegetations are often associated with endocarditis. They can be made of fibrin and platelets. == Types == Certain conditions are associated with specific vegetation patterns: == References ==


id: vip-medicine-20260505-0
file: data/en.wikipedia.org/wiki/VIP_medicine-0.md
category: reference
title: VIP medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/VIP_medicine
date_saved: 2026-05-05T07:34:04.879770+00:00
instance: kb-cron
parent: vip-medicine-20260505-0
summary:
VIP medicine is a variety of the VIP syndrome—the phenomenon of a perceived "VIP" (very important person) using his or her status to influence a given professional or institution to make unorthodox decisions under the pressure or presence of said VIP—that relates to the accessibility and quality of health care. It is essentially health care in which a physician or hospital accommodates a wealthy, important or famous patient who can afford to pay the full medical bill outright, usually with luxury amenities, and seclusion from the ordinary run of patient, as added benefits. As a result, such a patient may receive something other than the normal standard of care; the deviation may be in the direction of either greater or lesser safety and quality. VIP medicine may be initially reflected in expedited care in an emergency room or more immediate and direct access to specialists, bypassing primary care providers. A "VIP suite", or "wing", is one venue where VIP medicine may be practiced in the hospital setting—indeed, whole floors of a hospital building, at major medical centers, may be dedicated to it. A particular type of formalized and regularized VIP medical practice is known as concierge medicine. Many aspects of


id: vip-medicine-20260505-1
file: data/en.wikipedia.org/wiki/VIP_medicine-1.md
category: reference
title: VIP medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/VIP_medicine
date_saved: 2026-05-05T07:34:04.879770+00:00
instance: kb-cron
parent: vip-medicine-20260505-0
summary:
Hospitals and doctors aiming to give some patients more medical care, more time, and more resources contradicts fundamental medical ethics. It may not be consistent with the idea of justice within medicine: a fair distribution of scarce resources. VIP medicine can be extravagant and wasteful. Excessive drug prescriptions may be written and imaging studies ordered. Some health care programs for corporate executives, for example, involve periodic full-body CT scans as screening tests as part of the "chairman's physical", a measure considered entirely unjustified as routine care. Overmedication may result. Imaging tests may actually increase the risk of cancer from radiation exposure and have never really been shown to improve anyone's health. And if there is an incidental finding, as there often is, more tests might be ordered, which may lead to unnecessary biopsies. A VIP may insist on the senior-most specialist at an academic institution or teaching hospital—the chair of the department of medicine, or of surgery, for instance. But the senior-most, or most eminent, caregiver is not necessarily the most skilled at performing a given procedure. Such an individual may be out of practice, or no longer up-to-date, and the "no name" subordinate may actually be much more skilled.


id: waiting-in-healthcare-20260505-0
file: data/en.wikipedia.org/wiki/Waiting_in_healthcare-0.md
category: reference
title: Waiting in healthcare
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Waiting_in_healthcare
date_saved: 2026-05-05T07:34:06.106767+00:00
instance: kb-cron
parent: waiting-in-healthcare-20260505-0
summary:
Waiting in healthcare refers to any waiting period experienced by a patient before or during medical treatment. Waiting to get an appointment with a physician, staying in a waiting room before an appointment, and being observed during a physician's watchful waiting are different concepts in waiting for healthcare. When a patient is waiting, their family and friends may also be waiting for an outcome. Waiting time influences patient satisfaction. Patients can spend longer waiting for treatment than actually receiving treatment. Some experts have suggested that patient waiting rooms in hospitals be integrated with the other rooms providing patient care so that information updates can come freely to anyone waiting. Time in the waiting room has been used to experiment with giving patient health education. In 2014 the Patient-Centered Outcomes Research Institute began funding a study for improving the waiting room experience. Patients who are waiting for surgery depend on the availability of the operating theater, and if any patient getting treatment in that room takes longer than scheduled, all patients who are waiting to be next must wait beyond their appointed time. It can be difficult to maximize efficient use of the operating room when unexpected delays can happen and


id: watchful-waiting-20260505-0
file: data/en.wikipedia.org/wiki/Watchful_waiting-0.md
category: reference
title: Watchful waiting
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Watchful_waiting
date_saved: 2026-05-05T07:34:07.307836+00:00
instance: kb-cron
parent: watchful-waiting-20260505-0
summary:
Watchful waiting (also watch and wait or WAW) is an approach to a medical problem in which time is allowed to pass before medical intervention or therapy is used. During this time, repeated testing may be performed. Related terms include expectant management, active surveillance (especially active surveillance of prostate cancer), and masterly inactivity. The term masterly inactivity is also used in nonmedical contexts. A distinction can be drawn between watchful waiting and medical observation, but some sources equate the terms. Usually, watchful waiting is an outpatient process and may have a duration of months or years. In contrast, medical observation is usually an inpatient process, often involving frequent or even continuous monitoring and may have a duration of hours or days. == Medical uses == Often watchful waiting is recommended in situations with a high likelihood of self-resolution if there is high uncertainty concerning the diagnosis, and the risks of intervention or therapy may outweigh the benefits. Watchful waiting is often recommended for many common illnesses such as ear infections in children; because the majority of cases resolve spontaneously, antibiotics will often be prescribed only after several days of symptoms. It is also a strategy frequently used in surgery prior


id: weekend-effect-20260505-0
file: data/en.wikipedia.org/wiki/Weekend_effect-0.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
In healthcare, the weekend effect is the finding of a difference in mortality rate for patients admitted to hospital for treatment at the weekend compared to those admitted on a weekday. The effects of the weekend on patient outcomes has been a concern since the late 1970s, and a 'weekend effect' is now well documented. Although this is a controversial area, the balance of opinion is that the weekend (and bank holidays) have a deleterious effect on patient care (and specifically increase mortality)—based on the larger studies that have been carried out. Variations in the outcomes for patients treated for many acute and chronic conditions have been studied. == Published research: Non-disease specific (unselected) patients == === Medical patients === Schmulewitz et al., in the UK in 2005, studied 3,244 patients with chronic obstructive pulmonary disease, cerebrovascular accidents, pulmonary embolism, pneumonia, collapse and upper gastrointestinal bleed. They found "Weekend admission was not associated with significantly higher in-hospital mortality, readmission rates or increased length of stay compared to the weekday equivalent for any of the six conditions". However, in 2010, Clarke et al., in a much larger Australian study of 54,625 mixed medical/surgical non-elective admissions showed a significant weekend effect (i.e.


id: weekend-effect-20260505-1
file: data/en.wikipedia.org/wiki/Weekend_effect-1.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Surgical patients === Non-elective (emergency) Patients There have been many similar studies (with similar conclusions) in surgery. In the US, in a very large study in 2011, 29,991,621 non-elective general surgical hospital admissions were studied (Ricciardi et al.). Inpatient mortality was reported as 2.7% for weekend and 2.3% for weekday admissions (p<0.001). Regression analysis revealed significantly higher mortality during weekends for 15 of the 26 (57.7%) major diagnostic categories. The weekend effect remained, and mortality was noted to be 10.5% higher during weekends compared with weekdays after adjusting for all other variables. In another huge US study in 2016 (Ricciardi et al., 2016), 28,236,749 non-elective surgical patients were evaluated, with 428,685 (1.5%) experiencing one or more Patient Safety Indicator (PSI) events. The rate of PSI was the same for patients admitted on weekends as compared to weekdays (1.5%). However, the risk of mortality was 7% higher if a PSI event occurred to a patient admitted on a weekend, as compared with a weekday. In addition, compared to patients admitted on weekdays, patients admitted on weekends had a 36% higher risk of postoperative wound dehiscence, 19% greater risk of death in a low-mortality diagnostic-related group, 19% increased risk of postoperative


id: weekend-effect-20260505-2
file: data/en.wikipedia.org/wiki/Weekend_effect-2.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Emergency department (ED) patients === ED admissions have also been well studied. The first major study was published in 2001 by Bell et al. In this Canadian study, 3,789,917 ED admissions were analysed. Weekend admissions were associated with significantly higher in-hospital mortality rates than weekday admissions among patients with ruptured abdominal aortic aneurysms (42% vs 36%, p<0.001), acute epiglottitis (1.7% vs 0.3%, p=0.04), and pulmonary embolism (13% vs 11%, p=0.009). In another Canadian study (Cram et al., 2004), 641,860 admissions from the ED were investigated. The adjusted odds of death for patients admitted on weekends when compared with weekdays was 1.03 (95% CI 1.01-1.06; p=0.005). The weekend effect was larger in major teaching hospitals compared with non-teaching hospitals (OR = 1.13 vs 1.03, p=0.03) and minor teaching hospitals (OR = 1.05, p=0.11). In a UK study in 2010, Aylin et al. studied 4,317,866 ED admissions, and found 215,054 in-hospital deaths with an overall crude mortality rate of 5.0% (5.2% for all weekend admissions and 4.9% for all weekday admissions). The overall adjusted odds of death for all emergency admissions was 10% higher (OR = 1.10; 95% CI 1.08-1.11) in those patients admitted at the weekend compared with patients admitted


id: weekend-effect-20260505-3
file: data/en.wikipedia.org/wiki/Weekend_effect-3.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Intensive care unit patients === As well as ED, ICU care has been extensively studied in terms of weekend mortality. In 2002, Barnett et al. studied 156,136 patients in the US. They found the in-hospital death was 9% higher (OR = 1.09; 95% CI 1.04-1.15; p<0.001) for weekend admissions (Saturday or Sunday) than in patients admitted midweek (Tuesday to Thursday). However, the adjusted odds of death were also higher (p<0.001) for patients admitted on a Monday (OR = 1.09) or a Friday (OR = 1.08). Findings were generally similar in analyses stratified by admission type (medical vs. surgical), hospital teaching status, and illness severity. In 2003, in Finland, Uusaro et al., studied 23,134 consecutive ICU patients. Adjusted ICU-mortality was higher for weekend as compared with weekday admissions (OR = 1.20; 95% CI 1.01-1.43). But not all ICU studies show an effect. For example, in the following year, Ensminger et al.(2004) published a similar study in the US, looking at a significantly smaller population (of 29,084 patients). In multivariable analyses - controlling for the factors associated with mortality such as APACHE (acute physiology and chronic health evaluation) III predicted mortality rate, ICU admission source, and intensity of treatment - no


id: weekend-effect-20260505-4
file: data/en.wikipedia.org/wiki/Weekend_effect-4.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Other non-selected patients === Schilling et al., in 2010, investigated 166,920 patients admitted to 39 Michigan hospitals. Participants were adults, 65 years+, and admitted through the emergency department with six common discharge diagnoses (acute myocardial infarction, congestive heart failure, stroke, pneumonia, hip fracture, gastrointestinal bleeding). Seasonal influenza conferred the greatest increase in absolute risk of in-hospital mortality (0.5%; 95% CI 0.23-0.76), followed by weekend admission (0.32%; 95% CI 0.11-0.54), and high hospital occupancy on admission (0.25; 95% CI 0.06-0.43). In a huge study in 2012 by Freemantle et al., 14,217,640 admissions (all types) were assessed. Admission on weekend days was associated with an increase in risk of subsequent death compared with admission on weekdays. Hazard ratio for Sunday vs Wednesday 1.16 (95% CI 1.14-1.18; p<0.0001), and for Saturday vs Wednesday 1.11 (95% CI 1.09-1.13; p<.0001). Also in 2012, Lee et al., in Malaysia, studied 126,627 patients admitted to a single hospital. The group found that there was a statistically significant increased risk of mortality for those patients admitted during weekends (OR = 1.22; 95% CI 1.14-1.31) and out-of-hours on a weekday (OR = 1.67; 95% CI 1.57-1.78). As well as the effect of the weekend, there is a considerable


id: weekend-effect-20260505-5
file: data/en.wikipedia.org/wiki/Weekend_effect-5.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
== Published research: Disease-specific (selected) patients: Cardiorespiratory medicine == === Cardiology === AMI Multiple studies have been carried out into acute myocardial infarction (AMI). In the first study, in Japan in 2007, Matsui et al. studied 6084 patients. There were no differences between the weekday and weekend groups in terms of in-hospital, 30-day, and 1-year mortality rates. However, also in 2007, in a much larger US study (of 231,164 AMI patients), Kostis et al. found that the difference in mortality at 30 days was significant even after adjustment for demographic characteristics, coexisting conditions, and site of infarction (OR = 1.048; 95% CI 1.02-1.08; p<0.001). In 2008, Kruth et al. in Germany, analysed 11,516 patients with ST-elevation myocardial infarction (STEMI). On weekends the group found a significantly higher in-hospital mortality (11.1 vs 9.4%, p=0.01) and at night there was a trend to higher in-hospital mortality when compared with regular working hours (10.6 vs 9.4%, p=0.07). In small Japanese study, two years later, 370 AMI patients were studied (Turin et al., 2009). Odds ratio was 1.18 (95% CI 0.7-1.9) but there was no significant difference between weekend and weekday patients. Similarly, also in 2010, in South Korea, in another large study (97,466


id: weekend-effect-20260505-6
file: data/en.wikipedia.org/wiki/Weekend_effect-6.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Other cardiac disease === Three studies have been carried out into Acute Heart Failure (AHF). In 2009, in a US study of 48,612 patients with AHF, there were no differences in death rate by day of admission or discharge (Fornarow et al.). Conversely, in the same year, also in the US, Horwich et al. analysed 81,810 AHF admissions at 241 sites. Weekend AHF admission compared to weekday admission was associated with an increased in-hospital mortality (OR = 1.13; 95% CI 1.02-1.27). In a smaller Japanese study (of 1620 patients) in 2014, Hamaguchi et al., found in-hospital death was comparable between patients admitted on the weekend and weekdays (OR = 1.13; 95% CI 1.63-2.00; p=0.69). Deshmukh et al., in the US in 2012, analysed 86,497 discharges with atrial fibrillation. The rate of AF requiring cardioversion was lower at the weekend when compared to a weekday (7.9% vs 16.2%, p<0.0001; OR = 0.5, 95% CI 0.45-0.55; p<0.0001). The adjusted hospital mortality odds was greater for weekend admissions (OR = 1.23, 95% CI 1.03-1.51; p<0.0001), after adjusting for patient and hospital characteristics and disease severity. === Cardiovascular surgery === There have been three studies in cardiovascular surgery. In 2011, Kim et al.


id: weekend-effect-20260505-7
file: data/en.wikipedia.org/wiki/Weekend_effect-7.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Gastroenterology === Upper GI Bleed The studies related to Upper GI Bleed (UGIB) are almost as numerous as those on myocardial infarction; two focus on Acute Variceal Hemorrhage (AVH) alone. In 2009, in the US, Shaheen et al., found, in a study of 237,412 patients with UGI bleed, that those admitted on the weekend had an increased risk of death (3.4% vs 3.0%; OR = 1.08; 95% CI 1.02-1.15). In a similar US paper that year, Ananthakrishnan et al., studied another very large population (of 419,939 patients with UGIB). On multivariate analysis, non-variceal UGIB patients admitted on weekends had higher adjusted in-hospital mortality (OR = 1.21; 95% CI 1.09-1.35). Whereas, weekend admission was not predictive of in-hospital mortality in patients with AVH (OR = 0.94; 95% CI 0.75-1.18). In another similar US study, by Dorn et al., in 2010, 98,975 patients with UGIB were studied, and a similar weekend effect found. Compared to patients admitted on a weekday, for those admitted on a weekend, in-hospital mortality was higher (unadjusted mortality 3.76 vs 3.33%; p = 0.003; adjusted OR = 1.09, 95% CI 1.00-1.18). Whereas, in a much smaller 2011 UK study (of 6749 patients), Jaraith et al., no weekend


id: weekend-effect-20260505-8
file: data/en.wikipedia.org/wiki/Weekend_effect-8.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Nephrology and transplantation === In a very large Canadian study (of 963,730) patients, in 2010, James et al., showed that (compared with admission on a weekday), AKI patients admitted on a weekend had a higher risk of death (OR = 1.07; 95% CI 1.02-1.12). Similarly, in a huge study of 3,278,572 American haemodialysis patients in 2013, Sakhuja et al., concluded that patients admitted over weekends had higher mortality during the first 3 days of admission (OR = 1.18; 95% CI 1.10-1.26). Haddock et al., in the UK, in 2015, studied admissions to a renal unit. No weekend effect was observed. Thirty-day mortality rate was 46/208 = 0.22 deaths/weekend day of admission compared with 107/523 = 0.20 deaths/weekday of admission (OR = 1.08, p = 0.67). Acute kidney injury and haemodialysis patients formed a higher percentage of admissions. Orman et al., in 2012, in the US, studied 94,768 liver transplants. The patient survival rates did not significantly differ from those for daytime and weekday operations. The graft failure rate was unchanged at 30 and 90 days for weekend transplants but was modestly increased at 365 days (OR = 1.05; 95% CI 1.01-1.11). In 2016, an American study of 181,799 deceased


id: weekend-effect-20260505-9
file: data/en.wikipedia.org/wiki/Weekend_effect-9.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Neurology === Stroke With myocardial infarction and UGIB, the most well studied disease is stroke, with varying results regarding the weekend effect. Though there are three very large studies (>100,000 patients), two of which are positive. In the first stroke study, by Saposnik et al. in 2007, 26,676 patients in 606 hospitals in Canada were assessed. Seven-day stroke mortality was 7.6%. Weekend admissions were associated with a higher stroke mortality than weekday admissions (8.5% vs 7.4%). In the multivariable analysis, weekend admissions were associated with higher early mortality (OR = 1.14; 95% CI 1.02-1.26) after adjusting for age, sex, comorbidities, and medical complications. In Japan in the following year, a much smaller study of 1578 patients, was carried out by Turin et al. They found the 28-day case fatality rate for the weekend admission group was 14.7% (95% CI 11.3-18.8) and 10.1% (95% CI 8.5-11.9) for the weekday admission group. This phenomenon was observed mainly for cerebral infarction, and to some extent for cerebral haemorrhage. But it did not reach statistical significance. In 2009, Tung et al., in Taiwan, studied 34,347 ischaemic stroke patients and found that weekend admissions were associated with increased 30-day mortality. Five studies were published


id: weekend-effect-20260505-10
file: data/en.wikipedia.org/wiki/Weekend_effect-10.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
Hsieh et al., in Taiwan, analysed 46,007 ischaemic stroke admissions. They found, in multivariate analysis without adjustment for stroke severity, weekend admission was associated with increased 30-day mortality (OR = 1.20; 95% CI 1.08-1.34). But this association did not persist after adjustment for stroke severity (OR = 1.07; 95% CI 0.95-1.20). Whereas, Ansa et al., in Nigeria in 2016, studied 339 patients, of which 187 (55.2%) had had a stroke. They found presentation to hospital after-hours was a significant predictor of death (OR = 3.37). There has been one study of stroke in (8467) children, by Adil et al., in the US, in 2016. After adjusting for age, sex, and confounders, the odds of in-hospital mortality remained higher among children admitted on weekends (OR = 1.4; 95% CI 1.1-1.9; p=0.04). Other neurological disease One study related to meningococcal septicaemia has been published. In 2013, Goldacre et al., in a UK study of 19,729 patients, found that the risk of in-hospital death was significantly higher (OR = 1.12; 95% CI 1.05-1.20) for weekend admission.


id: weekend-effect-20260505-11
file: data/en.wikipedia.org/wiki/Weekend_effect-11.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Neurosurgery === Intracranial haemorrhage Several studies have been published regarding intracranial bleeding: intracerebral, subarachnoid and subdural haemorrhage. In 2009 in the US, Crowley et al., in a study of 13,821 US patients with intracerebral haemorrhage (ICH), reported the risk of in-hospital death was 12% higher with weekend admission (OR = 1.12; 95% CI 1.05-1.20). In China, in 2012, Jiang et al., in a much smaller study (of 313 patients with ICH) found that weekend admission was not a statistically significant predictive factor of in-hospital mortality (p=0.315) or functional outcome (p=0.128). However, in 2016, Patel et al., also in the US, studied 485,329 patients with intracerebral haemorrhage (ICH). Overall, weekend admission was associated with 11% higher odds of in-hospital mortality. When analysed in 3-year groups, excess mortality of weekend admissions showed temporal decline. Three relatively small studies on SAH have been carried out. Crowley et al., in the US in 2009, investigated patients with subarachnoid haemorrhage (SAH; 5667 patients). Unlike the group's other study, weekend admission was not a statistically significant independent predictor of death in the study population at 7 days (OR = 1.07, 95% CI 0.91-1.25), 14 days (OR = 1.01, 95% CI 0.87-1.17), or 30 days (OR


id: weekend-effect-20260505-12
file: data/en.wikipedia.org/wiki/Weekend_effect-12.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
== Published research: Disease-specific (selected) patients: Paediatrics and obstetrics == Neonatal mortality Several paediatric and obstetric studies have been performed. In fact, the first studies on the weekend effect were in this area in the late 1970s. Possibly the first study of the weekend effect was a UK prospective study of 297,000 children, published in 1977, when childhood deaths were assessed. The paper stated "16 of the 29 sudden unexpected deaths occurred at a weekend or bank holiday". In 1981, Hendry in the UK, stated that "babies born on Sundays were more at risk of dying during or after birth." Also in 1981, in the US, Mangold studied 66,049 live births. Neonatal mortality was found to be higher among weekend deliveries with a Sunday rate that was 27 per cent above the weekly average. Two years later, in Australia, Mathers concluded that "stillbirth and neonatal death rates were 17% and 29% higher respectively among babies born at weekends than among those born on weekdays". In 2003, Hamilton et al., in an American study of 111,749 births, found that neonatal mortality was higher among the births on weekends than those during the week. However, in the same year, Gould et al.


id: weekend-effect-20260505-13
file: data/en.wikipedia.org/wiki/Weekend_effect-13.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== General surgery === The weekend effect have been assessed in a wide range of specific surgical conditions. Four studies were published in 2012. Worni et al., in the US, studied 151,774 patients who had had a laparoscopic appendectomy. Overall mortality (OR = 1.37; p=0.075) was not statistically different between weekday and weekend groups. Whereas the same group, found a weekend effect in a study of 31,832 patients who underwent urgent surgery for left-sided diverticulitis (Worni et al., 2012). In a risk-adjusted analysis, patients admitted on weekends had a significantly higher risk for any postoperative complication (OR = 1.10; p=0.005). A mortality analysis was not presented. In the same year, in a small study of 404 US patients with small bowel obstruction, McVay et al., found that mortality was low at 1.7%, with no difference noted between the groups (p=0.35). This is not surprising with a small study of a lowish risk procedure. In the US, Orman et al., studied 94,768 liver transplant patients. Unadjusted Cox proportional hazards modelling showed that in comparison with weekday liver transplant patients, weekend liver transplant patients had an OR of 0.99 (95% CI 0.93-1.07) for mortality at 30 days (i.e. no weekend effect). In


id: weekend-effect-20260505-14
file: data/en.wikipedia.org/wiki/Weekend_effect-14.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
=== Vascular surgery === Two studies of ruptured abdominal aortic aneurysm (AAA) have been carried out. Both demonstrated the weekend effect. In 2012, Gellerani et al., in Italy, investigated 4461 patients. Weekend admissions were associated with significantly higher in-hospital mortality (43.4%) than weekday admissions (36.9%; p<0.001). Multivariate regression analysis showed that weekend admission was an independent risk factor for increased in-hospital mortality (OR = 1.32; 95% CI 1.14-1.52; p<0.001). Two years later, in the US, in a study of 5832 patients, Groves et al. found that patients admitted on the weekend had a statistically significant increase in mortality compared with those admitted on the weekdays (OR = 1.32; 95% CI 1.13-1.55; p=0.0004). There are also two studies on lower limb ischaemia, both performed in the US. In a study of 63,768 patients with an ischaemic lower limb in 2014, Orandi et al. found no statistically significant association between weekend admission and in-hospital mortality (OR = 1.15; 95% CI 1.06-1.25; p=0.10). Whereas, Arora et al., a year later, in a similar study, did show a weekend effect. They found through multivariate analysis, that weekend admission (OR = 1.53; 95% CI 1.26-1.86; p<0.001) was a significant predictor of inhospital mortality. In 2015,


id: weekend-effect-20260505-15
file: data/en.wikipedia.org/wiki/Weekend_effect-15.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
== Published research: Discussion == This weekend effect is seen in non-selected (non disease-specific) studies, medical and surgical; for both non-elective and elective admissions, in most countries in the developed world. In fact, the strength of the effect is highest in elective surgical care; the highest relative risk being 3.18 in Glance et al in 2016, and 1.82 in Aylin et al, in 2013. However, it is not entirely valid to compare weekend vs weekday mortality in elective and non-elective surgical patients; as they may not be from the same patient groups - e.g. the elective patients may be older, with comorbidities, with degenerative or malignant disease (e.g. hip replacement or bowel carcinoma), and the non-elective younger with infection or inflammation (e.g. appendicitis). In terms of the disease-specific studies, the larger studies showed good evidence for a weekend effect in myocardial infarction, cardiac arrest, AF, pulmonary embolus, COPD, pneumonia, upper GI bleed, stroke (probably), AAA; and in specialties including plastic surgery, and paediatrics and obstetrics (probably), including SIDS. There is variable evidence of an effect in ICU and psychiatry; and no evidence of an effect in disease group-specific studies in general, orthopaedic, vascular and other specialist surgery. Public holidays, and


id: weekend-effect-20260505-16
file: data/en.wikipedia.org/wiki/Weekend_effect-16.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
== Cause of weekend effect == The cause of this effect is unclear. It could be a 'purely medical problem', i.e. the mortality is increased due to reduced medical staffing levels at the weekend. The cardiology, nephrology, paediatric and obstetric studies are against this argument; as these are all specialties where senior medical staff usually work normally at weekends. It could be due to a combination of medical, nursing and other health professional staff being less available at weekends. There is some evidence for the importance of nursing numbers, in terms of weekend mortality. In Neuraz et al's study in 2015, the patient-to-nurse ratio was more important that the ratio of patient-to-physician. Alternatively, the effect may not just be a health issue, i.e. it could be due to reduced health and social care availability (that the patient may be discharged into) at the weekend. As described above in the Discussion, there is also considerable literature on the 'Out-of-Hours Effect'. This effect is seen during the week and at weekends. The study by Lee et al in 2012, looked at (and compared) the 'Out-of-Hours' and 'Weekend Effect' on the same dataset (of 126,627 patients). In this, and other such studies, the


id: weekend-effect-20260505-17
file: data/en.wikipedia.org/wiki/Weekend_effect-17.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
== Weekend effect and working patterns == A small number of studies have examined the evidence for an association between the weekend effect and patterns of health professional working; six studies have addressed medical staffing, two have addressed nursing issues, and two have addressed both. In 2011, in a study of COPD patients in the UK, Brims et al. found that after opening a Medical Admission Unit, the risk of death on day 1 after weekend winter admission fell from 3.63 (95% CI 1.15-11.5) to 1.65 (95% CI 0.14-19.01). Similarly, Bell et al., in 2013, in the UK, found an 'all inclusive' pattern of consultant working, incorporating a minimum consultant presence of 4 hours per day, was associated with reduced excess weekend mortality. In the US, in 2014, Ricciardi et al., in another medical study, found that mortality following a weekend admission for patients admitted to a hospital with resident trainees, was significantly higher than hospitals with no resident trainees. The effects of the introduction of a 7-day consultant service have been investigated in medical patients. In 2015, Leong et al., in an uncontrolled study of elderly medical patients in the UK, stated "introduction of seven-day consultant working was associated


id: weekend-effect-20260505-18
file: data/en.wikipedia.org/wiki/Weekend_effect-18.md
category: reference
title: Weekend effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weekend_effect
date_saved: 2026-05-05T07:34:08.663129+00:00
instance: kb-cron
parent: weekend-effect-20260505-0
summary:
In 2015, Health Secretary Jeremy Hunt quoted that the 'weekend effect' in the NHS equated to 11,000 excess deaths a year. Some are now reporting the Hunt Effect - that some patients, too scared to attend hospital at weekends because of the weekend effect, have become seriously ill or even died as a direct consequence of waiting until Monday before seeking medical advice. The authors state, "To assume that [the 11,000 deaths] are avoidable would be rash and misleading."The paper was criticised by some clinicians unhappy with the findings, and a comment by a professor of cardiovascular epidemiology suggested that the report was data-driven rather than based on a hypothesis; in fact the 2015 paper was a development from previous work which analysed an earlier data set in 2012. In response to the 'weekend effect' and the lack of seven day elective services, there have been proposals for major reform to contracts of NHS staff. Staff are in support of strengthening weekend services, but junior doctors have criticised these changes as they do not account for the 40% increase in workload. The UK's main doctors union, the British Medical Association, is still negotiating, as they would like assurances that new


id: wells-score-pulmonary-embolism-20260505-0
file: data/en.wikipedia.org/wiki/Wells_score_(pulmonary_embolism)-0.md
category: reference
title: Wells score (pulmonary embolism)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wells_score_(pulmonary_embolism)
date_saved: 2026-05-05T07:34:09.962673+00:00
instance: kb-cron
parent: wells-score-pulmonary-embolism-20260505-0
summary:
The Wells score is a clinical prediction rule used to classify patients suspected of having pulmonary embolism (PE) into risk groups by quantifying the pre-test probability. It is different than Wells score for DVT (deep vein thrombosis). It was originally described by Wells et al. in 1998, using their experience from creating Wells score for DVT in 1995. Today, there are multiple (revised or simplified) versions of the rule, which may lead to ambiguity. The purpose of the rule is to select the best method of investigation (e.g. D-dimer testing, CT angiography) for ruling in or ruling out the diagnosis of PE, and to improve the interpretation and accuracy of subsequent testing, based on a Bayesian framework for the probability of the diagnosis. The rule is more objective than clinician gestalt, but still includes subjective opinion (unlike e.g. Geneva score). == External links == Wells Score PE Calculator – Free online calculator for clinical use == Original algorithm == Source: Originally it was developed in 1998 to improve the low specificity of V/Q scan results (which then had a more important role in the workup of PE than now). It categorized patients into 3 categories: low / moderate / high


id: worried-well-20260505-0
file: data/en.wikipedia.org/wiki/Worried_well-0.md
category: reference
title: Worried well
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Worried_well
date_saved: 2026-05-05T07:34:11.075850+00:00
instance: kb-cron
parent: worried-well-20260505-0
summary:
The worried well is a term that describes persons who are in relatively good health but believe themselves to be ill or likely to get an illness based on a current circumstance. As a collective noun, the term is typically used for groups of patients, not clearly defined, who are perceived to be using health services inappropriately or disproportionately. The phenomenon is also known as worried well syndrome. The worried well are within ICD-10 code Z71.1—"Person with feared complaint in whom no diagnosis is made." They are distinct from those suffering from hypochondriasis (health anxiety), whose health concerns are chronic and rise to the level of a psychiatric condition; in contrast, anxiety experienced by worried well patients is usually caused by a specific event. == Etymology == The term worried well, according to the Oxford English Dictionary, was first used in a 1970 Scientific American article by physician Sidney Garfield, who described a "variable entry mix into medical care consisting of (1) the well, (2) the ‘worried well’, (3) the ‘early sick’ and (4) the sick." In 1997, The Times wrote that "Mental health experts...have...nicknamed them the ‘worried well’—too disturbed to sail through life's challenges but too well to warrant


id: yentl-syndrome-20260505-0
file: data/en.wikipedia.org/wiki/Yentl_syndrome-0.md
category: reference
title: Yentl syndrome
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Yentl_syndrome
date_saved: 2026-05-05T07:34:12.240911+00:00
instance: kb-cron
parent: yentl-syndrome-20260505-0
summary:
The Yentl syndrome refers to the under-diagnosis of ischemic heart disease (IHD) in women compared to men, as well as the general gender disparity in cardiovascular health research. The name is taken from the 1983 film Yentl starring Barbra Streisand in which her character plays the role of a male in order to receive the education she desires. The phrase was coined in a 1991 academic paper by Dr. Bernadine Healy titled "The Yentl syndrome", where she condemned the characterization of coronary heart disease as only prevalent in males and called for awareness of gender differences in health. Cardiovascular disease (CVD) is the leading cause of death in women worldwide, yet it continues to be under-recognized and under-treated due to a complex interplay of biological, social, and cultural factors. Historically, women's health concerns were often dismissed, and although significant improvements have been made, implicit gender biases persist leading to delays in diagnosis and treatment. Low awareness further contributes to disparities, as many women underestimate their cardiovascular risk and providers may not consistently view CVD as a primary concern. Beyond these systemic issues, biological differences between sexes play an important role. There are also female-specific risk factors for cardiovascular disease to


id: zebra-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Zebra_(medicine)-0.md
category: reference
title: Zebra (medicine)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Zebra_(medicine)
date_saved: 2026-05-05T07:34:13.381602+00:00
instance: kb-cron
parent: zebra-medicine-20260505-0
summary:
Zebra is American medical slang for a surprising, often exotic, medical diagnosis, especially when a more commonplace explanation is more likely. It is shorthand for the aphorism coined in the late 1940s by Theodore Woodward, professor at the University of Maryland School of Medicine, who instructed his medical interns: "When you hear hoofbeats behind you, don't expect to see a zebra." (Alternative phrasing: "When you hear hoofbeats, think of horses, not zebras." Since zebras are much rarer than horses in the United States, the sound of hoofbeats would almost certainly be from a horse.) By 1960, the aphorism was widely known in medical circles. The saying is a warning against the statistical base rate fallacy where the likelihood of something like a disease among the population is not taken into consideration for an individual. Medical novices are predisposed to make rare diagnoses because of (a) the availability heuristic ("events more easily remembered are judged more probable") and (b) the phenomenon first enunciated in Rhetorica ad Herennium (c. 85 BC), "the striking and the novel stay longer in the mind." Thus, the aphorism is an important caution against these biases when teaching medical students to weigh medical evidence. Diagnosticians have noted,


id: abyssal-plain-20260505-0
file: data/en.wikipedia.org/wiki/Abyssal_plain-0.md
category: reference
title: Abyssal plain
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_plain
date_saved: 2026-05-05T07:34:14.960702+00:00
instance: kb-cron
parent: abyssal-plain-20260505-0
summary:
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3,000 and 6,000 metres (9,800 and 19,700 ft). Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. They are among the flattest, smoothest, and least explored regions on Earth. Abyssal plains are key geologic elements of oceanic basins, the other elements being an elevated mid-ocean ridge and flanking abyssal hills. The creation of the abyssal plain is the result of the spreading of the seafloor (plate tectonics) and the melting of the lower oceanic crust. Magma rises from above the asthenosphere (a layer of the upper mantle), and as this basaltic material reaches the surface at mid-ocean ridges, it forms new oceanic crust, which is constantly pulled sideways by spreading of the seafloor. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. Much of this sediment is deposited by turbidity currents that have been channelled from the continental margins along submarine canyons into deeper water. The rest is composed chiefly of pelagic sediments. Metallic nodules are common


id: abyssal-plain-20260505-1
file: data/en.wikipedia.org/wiki/Abyssal_plain-1.md
category: reference
title: Abyssal plain
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_plain
date_saved: 2026-05-05T07:34:14.960702+00:00
instance: kb-cron
parent: abyssal-plain-20260505-0
summary:
The ocean can be conceptualized as zones, depending on depth, and presence or absence of sunlight. Nearly all life forms in the ocean depend on the photosynthetic activities of phytoplankton and other marine plants to convert carbon dioxide into organic carbon, which is the basic building block of organic matter. Photosynthesis in turn requires energy from sunlight to drive the chemical reactions that produce organic carbon. The stratum of the water column nearest the surface of the ocean (sea level) is referred to as the photic zone. The photic zone can be subdivided into two different vertical regions. The uppermost portion of the photic zone, where there is adequate light to support photosynthesis by phytoplankton and plants, is referred to as the euphotic zone (also referred to as the epipelagic zone, or surface zone). The lower portion of the photic zone, where the light intensity is insufficient for photosynthesis, is called the dysphotic zone (dysphotic means "poorly lit" in Greek). The dysphotic zone is also referred to as the mesopelagic zone, or the twilight zone. Its lowermost boundary is at a thermocline of 12 °C (54 °F), which, in the tropics generally lies between 200 and 1,000 metres (660 and


id: abyssal-plain-20260505-2
file: data/en.wikipedia.org/wiki/Abyssal_plain-2.md
category: reference
title: Abyssal plain
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_plain
date_saved: 2026-05-05T07:34:14.960702+00:00
instance: kb-cron
parent: abyssal-plain-20260505-0
summary:
Oceanic crust, which forms the bedrock of abyssal plains, is continuously being created at mid-ocean ridges (a type of divergent boundary) by a process known as decompression melting. Plume-related decompression melting of solid mantle is responsible for creating ocean islands like the Hawaiian islands, as well as the ocean crust at mid-ocean ridges. This phenomenon is also the most common explanation for flood basalts and oceanic plateaus (two types of large igneous provinces). Decompression melting occurs when the upper mantle is partially melted into magma as it moves upwards under mid-ocean ridges. This upwelling magma then cools and solidifies by conduction and convection of heat to form new oceanic crust. Accretion occurs as mantle is added to the growing edges of a tectonic plate, usually associated with seafloor spreading. The age of oceanic crust is therefore a function of distance from the mid-ocean ridge. The youngest oceanic crust is at the mid-ocean ridges, and it becomes progressively older, cooler and denser as it migrates outwards from the mid-ocean ridges as part of the process called mantle convection. The lithosphere, which rides atop the asthenosphere, is divided into a number of tectonic plates that are continuously being created and consumed at


id: abyssal-plain-20260505-3
file: data/en.wikipedia.org/wiki/Abyssal_plain-3.md
category: reference
title: Abyssal plain
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_plain
date_saved: 2026-05-05T07:34:14.960702+00:00
instance: kb-cron
parent: abyssal-plain-20260505-0
summary:
Beginning in 1916, Canadian physicist Robert William Boyle and other scientists of the Anti-Submarine Detection Investigation Committee (ASDIC) undertook research which ultimately led to the development of sonar technology. Acoustic sounding equipment was developed which could be operated much more rapidly than the sounding lines, thus enabling the German Meteor expedition aboard the German research vessel Meteor (1925–27) to take frequent soundings on east-west Atlantic transects. Maps produced from these techniques show the major Atlantic basins, but the depth precision of these early instruments was not sufficient to reveal the flat featureless abyssal plains. As technology improved, measurement of depth, latitude and longitude became more precise and it became possible to collect more or less continuous sets of data points. This allowed researchers to draw accurate and detailed maps of large areas of the ocean floor. Use of a continuously recording fathometer enabled Tolstoy & Ewing in the summer of 1947 to identify and describe the first abyssal plain. This plain, south of Newfoundland, is now known as the Sohm Abyssal Plain. Following this discovery many other examples were found in all the oceans. The Challenger Deep is the deepest surveyed point of all of Earth's oceans; it is at


id: abyssal-plain-20260505-4
file: data/en.wikipedia.org/wiki/Abyssal_plain-4.md
category: reference
title: Abyssal plain
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_plain
date_saved: 2026-05-05T07:34:14.960702+00:00
instance: kb-cron
parent: abyssal-plain-20260505-0
summary:
Though the plains were once assumed to be vast, desert-like habitats, research over the past decade or so shows that they teem with a wide variety of microbial life. However, ecosystem structure and function at the deep seafloor have historically been poorly studied because of the size and remoteness of the abyss. Recent oceanographic expeditions conducted by an international group of scientists from the Census of Diversity of Abyssal Marine Life (CeDAMar) have found an extremely high level of biodiversity on abyssal plains, with up to 2,000 species of bacteria, 250 species of protozoans, and 500 species of invertebrates (worms, crustaceans and molluscs), typically found at single abyssal sites. New species make up more than 80% of the thousands of seafloor invertebrate species collected at any abyssal station, highlighting our heretofore poor understanding of abyssal diversity and evolution. Richer biodiversity is associated with areas of known phytodetritus input and higher organic carbon flux. Abyssobrotula galatheae, a species of cusk eel in the family Ophidiidae, is among the deepest-living species of fish. In 1970, one specimen was trawled from a depth of 8,370 m (27,460 ft) in the Puerto Rico Trench. The animal was dead, however, upon arrival at the surface.


id: abyssal-plain-20260505-5
file: data/en.wikipedia.org/wiki/Abyssal_plain-5.md
category: reference
title: Abyssal plain
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_plain
date_saved: 2026-05-05T07:34:14.960702+00:00
instance: kb-cron
parent: abyssal-plain-20260505-0
summary:
Fueled by the chemicals dissolved in the vent fluids, these areas are often home to large and diverse communities of thermophilic, halophilic and other extremophilic prokaryotic microorganisms (such as those of the sulfide-oxidizing genus Beggiatoa), often arranged in large bacterial mats near cold seeps. In these locations, chemosynthetic archaea and bacteria typically form the base of the food chain. Although the process of chemosynthesis is entirely microbial, these chemosynthetic microorganisms often support vast ecosystems consisting of complex multicellular organisms through symbiosis. These communities are characterized by species such as vesicomyid clams, mytilid mussels, limpets, isopods, giant tube worms, soft corals, eelpouts, galatheid crabs, and alvinocarid shrimp. The deepest seep community discovered thus far is in the Japan Trench, at a depth of 7700 meters. Probably the most important ecological characteristic of abyssal ecosystems is energy limitation. Abyssal seafloor communities are considered to be food limited because benthic production depends on the input of detrital organic material produced in the euphotic zone, thousands of meters above. Most of the organic flux arrives as an attenuated rain of small particles (typically, only 0.5–2% of net primary production in the euphotic zone), which decreases inversely with water depth. The small particle flux can


id: abyssal-plain-20260505-6
file: data/en.wikipedia.org/wiki/Abyssal_plain-6.md
category: reference
title: Abyssal plain
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_plain
date_saved: 2026-05-05T07:34:14.960702+00:00
instance: kb-cron
parent: abyssal-plain-20260505-0
summary:
== Exploitation of resources == In addition to their high biodiversity, abyssal plains are of great current and future commercial and strategic interest. For example, they may be used for the legal and illegal disposal of large structures such as ships and oil rigs, radioactive waste and other hazardous waste, such as munitions. They may also be attractive sites for deep-sea fishing, and extraction of oil and gas and other minerals. Future deep-sea waste disposal activities that could be significant by 2025 include emplacement of sewage and sludge, carbon sequestration, and disposal of dredge spoils. As fish stocks dwindle in the upper ocean, deep-sea fisheries are increasingly being targeted for exploitation. Because deep sea fish are long-lived and slow growing, these deep-sea fisheries are not thought to be sustainable in the long term given current management practices. Changes in primary production in the photic zone are expected to alter the standing stocks in the food-limited aphotic zone. Hydrocarbon exploration in deep water occasionally results in significant environmental degradation resulting mainly from accumulation of contaminated drill cuttings, but also from oil spills. While the oil blowout involved in the Deepwater Horizon oil spill in the Gulf of Mexico originates from a


id: abyssal-zone-20260505-0
file: data/en.wikipedia.org/wiki/Abyssal_zone-0.md
category: reference
title: Abyssal zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_zone
date_saved: 2026-05-05T07:34:16.154926+00:00
instance: kb-cron
parent: abyssal-zone-20260505-0
summary:
The abyssal zone or abyssopelagic zone is a layer of the pelagic zone of the ocean. The word abyss comes from the Greek word ἄβυσσος (ábussos), meaning "bottomless". At depths of 4,000–6,000 m (13,000–20,000 ft), this zone remains in perpetual darkness. It covers 83% of the total area of the ocean and 60% of Earth's surface. The abyssal zone has temperatures around 2–3 °C (36–37 °F) through the large majority of its mass. The water pressure can reach up to 76 MPa (750 atm; 11,000 psi). As there is no light, photosynthesis cannot occur, and there are no plants producing molecular oxygen (O2), which instead primarily comes from ice that had melted long ago from the polar regions. The water along the seafloor of this zone is largely devoid of molecular oxygen, resulting in a death trap for organisms unable to quickly return to the oxygen-enriched water above or to survive in the low-oxygen environment. This region also contains a much higher concentration of nutrient salts, like nitrogen, phosphorus, and silica, due to the large amount of dead organic material that drifts down from the ocean zones above and decomposes. The region below the abyssal zone is the sparsely inhabited


id: abyssal-zone-20260505-1
file: data/en.wikipedia.org/wiki/Abyssal_zone-1.md
category: reference
title: Abyssal zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_zone
date_saved: 2026-05-05T07:34:16.154926+00:00
instance: kb-cron
parent: abyssal-zone-20260505-0
summary:
== Animals == The abyssal zone is made up of many different types of organisms, including microorganisms, crustaceans, molluscs (bivalves, snails, and cephalopods), different classes of fishes, and possibly some animals that have yet to be discovered. Most of the fish species in this zone are described as demersal or benthopelagic fishes. Demersal fish are fish whose habitats are on or near (typically less than five meters from) the seafloor. Most fish species fit into that classification, because the seafloor contains most of the abyssal zone's nutrients; therefore, the most complex food web or greatest biomass would be in this region of the zone. Organisms in the abyssal zone rely on the natural processes of higher ocean layers. When animals from higher ocean levels die, their carcasses occasionally drift down to the abyssal zone, where organisms in the deep can feed on them. When a whale carcass falls down to the abyssal zone, this is called a whale fall. The carcass of the whale can create complex ecosystems for organisms in the depths. Benthic organisms in the abyssal zone would need to have evolved morphological traits that could either keep them out of oxygen-depleted water above the sea floor or


id: abyssal-zone-20260505-2
file: data/en.wikipedia.org/wiki/Abyssal_zone-2.md
category: reference
title: Abyssal zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Abyssal_zone
date_saved: 2026-05-05T07:34:16.154926+00:00
instance: kb-cron
parent: abyssal-zone-20260505-0
summary:
== Environmental concerns == Climate change has had negative effects on the abyssal zone. Due to the zone's depth, increasing global temperatures do not affect it as quickly or drastically as the rest of the world, but the zone is still afflicted by ocean acidification. Pollutants, such as plastics, are also present in this zone. Plastics are especially bad for the abyssal zone because these organisms have evolved to eat or try to eat anything that moves or appears to be detritus, resulting in organisms consuming plastics instead of nutrients. Both ocean acidification and pollution are decreasing the already small biomass that resides within the abyssal zone. Another problem caused by humans is overfishing. Even though no fishery can fish for organisms anywhere near the abyssal zone, they can still cause harm in deeper waters. The abyssal zone depends on dead organisms from the upper zones sinking to the seafloor, since the ecosystem lacks producers due to a lack of sunlight. As fish and other animals are removed from the ocean, the frequency and amount of dead material reaching the abyssal zone decreases. Deep sea mining operations could cause problems for the abyssal zone in the future. The talks and


id: albufera-lagoon-20260505-0
file: data/en.wikipedia.org/wiki/Albufera_(lagoon)-0.md
category: reference
title: Albufera (lagoon)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Albufera_(lagoon)
date_saved: 2026-05-05T07:34:17.363720+00:00
instance: kb-cron
parent: albufera-lagoon-20260505-0
summary:
Albufera (Catalan/Valencian, 'lagoon') is the name of several estuarine lagoons in Spain: Albufera de València, on the Gulf of Valencia Albufera Natural Park, Natural Park in Valencia Albufera de Gaianes, in Gaianes (province of Alicante) S'Albufera de Mallorca, on the island of Mallorca S'Albufereta, also on Mallorca S'Albufera des Grau, on Menorca == See also == Albufeira, a city in Portugal


id: archipelago-20260505-0
file: data/en.wikipedia.org/wiki/Archipelago-0.md
category: reference
title: Archipelago
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archipelago
date_saved: 2026-05-05T07:34:18.531660+00:00
instance: kb-cron
parent: archipelago-20260505-0
summary:
An archipelago ( AR-kə-PEL-ə-goh), sometimes called an island group or island chain, is a chain, cluster, or collection of islands. An archipelago may be in an ocean, a sea, or a smaller body of water. Examples of archipelagos include the Aegean Islands (the origin of the term archipelago), the Canadian Arctic Archipelago, the Stockholm Archipelago, the Malay Archipelago (which includes the Indonesian and Philippine Archipelagos), the Lucayan (Bahamian) Archipelago, the Japanese archipelago, the Hawaiian Archipelago, and the Galapagos. == Etymology == The word archipelago is derived from the Italian arcipelago (used as a proper name for the Aegean Sea), itself perhaps a deformation of the Greek Αιγαίον Πέλαγος. Usage later shifted to refer to the Aegean Islands (since the sea has a large number of islands). The erudite paretymology, deriving the word from Ancient Greek ἄρχι- (arkhi-, "chief") and πέλαγος (pélagos, "sea"), proposed by Buondelmonti, can still be found. == Geographic types == Archipelagos may be found isolated in large bodies of water or neighboring a large land mass. For example, Scotland has more than 700 islands surrounding its mainland, which form an archipelago. Depending on their geological origin, islands forming archipelagos can be referred to as oceanic islands, continental


id: atoll-20260505-0
file: data/en.wikipedia.org/wiki/Atoll-0.md
category: reference
title: Atoll
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atoll
date_saved: 2026-05-05T07:34:19.794424+00:00
instance: kb-cron
parent: atoll-20260505-0
summary:
An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop. Most of the approximately 440 atolls in the world are in the Pacific Ocean. Two different, well-cited models, the subsidence model and the antecedent karst model, have been used to explain the development of atolls. According to Charles Darwin's subsidence model, the formation of an atoll is explained by the sinking of a volcanic island around which a coral fringing reef has formed. Over geologic time, the volcanic island becomes extinct and eroded as it subsides completely beneath the surface of the ocean. As the volcanic island subsides, the coral fringing reef becomes a barrier reef that is detached from the island. Eventually, the reef and the small coral islets on top of it are all that is left of the original island, and a lagoon has taken the place of the former volcano. The lagoon is not the former volcanic crater. For the atoll to persist, the coral reef must be maintained at the sea surface,


id: atoll-20260505-1
file: data/en.wikipedia.org/wiki/Atoll-1.md
category: reference
title: Atoll
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atoll
date_saved: 2026-05-05T07:34:19.794424+00:00
instance: kb-cron
parent: atoll-20260505-0
summary:
=== List of atolls === === Gallery === == Formation == In 1842, Charles Darwin explained the creation of coral atolls in the southern Pacific Ocean based upon observations made during a five-year voyage aboard HMS Beagle from 1831 to 1836. Darwin's explanation suggests that several tropical island types: from high volcanic island, through barrier reef island, to atoll, represented a sequence of gradual subsidence of what started as an oceanic volcano. He reasoned that a fringing coral reef surrounding a volcanic island in the tropical sea will grow upward as the island subsides (sinks), becoming an "almost atoll", or barrier reef island, as typified by an island such as Aitutaki in the Cook Islands, and Bora Bora and others in the Society Islands. The fringing reef becomes a barrier reef for the reason that the outer part of the reef maintains itself near sea level through biotic growth, while the inner part of the reef falls behind, becoming a lagoon because conditions are less favorable for the coral and calcareous algae responsible for most reef growth. In time, subsidence carries the old volcano below the ocean surface and the barrier reef remains. At this point, the island has become


id: barrier-island-20260505-0
file: data/en.wikipedia.org/wiki/Barrier_island-0.md
category: reference
title: Barrier island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Barrier_island
date_saved: 2026-05-05T07:34:21.177659+00:00
instance: kb-cron
parent: barrier-island-20260505-0
summary:
Barrier islands are a coastal landform, a type of dune system and sand island, where an area of sand off the coast has been formed by wave and tidal action parallel to the mainland coast. Barrier islands are commonly formed in long, narrow systems parallel to shorelines and are shaped by waves, tides, sediment movement, and sea-level change, which cause them to shift, grow, or erode over time. They protect coastlines by absorbing energy, and create areas of protected waters where wetlands may flourish. A barrier chain may extend for hundreds of kilometers, with islands periodically separated by tidal inlets. The longest barrier island in the world is Padre Island of Texas, United States, at 113 miles (182 km) long. Sometimes an important inlet may close permanently, transforming an island into a barrier peninsula, often including a barrier beach. Barrier islands are related to other coastal landforms such as barrier beaches and spits, which share similar physical features but differ primarily in their degree of attachment to the mainland and the presence of water on their landward side. Though many are long and narrow, the length and width of barriers and overall morphology of barrier coasts are related to parameters


id: barrier-island-20260505-1
file: data/en.wikipedia.org/wiki/Barrier_island-1.md
category: reference
title: Barrier island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Barrier_island
date_saved: 2026-05-05T07:34:21.177659+00:00
instance: kb-cron
parent: barrier-island-20260505-0
summary:
=== Critical width concept === Barrier islands are often formed to have a certain width. The term "critical width concept" has been discussed with reference to barrier islands, overwash, and washover deposits since the 1970s. The concept basically states that overwash processes were effective in migration of the barrier only where the barrier width is less than a critical value. The island did not narrow below these values because overwash was effective at transporting sediment over the barrier island, thereby keeping pace with the rate of ocean shoreline recession. Sections of the island with greater widths experienced washover deposits that did not reach the bayshore, and the island narrowed by ocean shoreline recession until it reached the critical width. The only process that widened the barrier beyond the critical width was breaching, formation of a partially subaerial flood shoal, and subsequent inlet closure. Critical barrier width can be defined as the smallest cross-shore dimension that minimizes net loss of sediment from the barrier island over the defined project lifetime. The magnitude of critical width is related to sources and sinks of sand in the system, such as the volume stored in the dunes and the net long-shore and cross-shore sand


id: barrier-island-20260505-2
file: data/en.wikipedia.org/wiki/Barrier_island-2.md
category: reference
title: Barrier island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Barrier_island
date_saved: 2026-05-05T07:34:21.177659+00:00
instance: kb-cron
parent: barrier-island-20260505-0
summary:
Scientists have proposed numerous explanations for the formation of barrier islands for more than 150 years. There are three major theories: offshore bar, spit accretion, and submergence. No single theory can explain the development of all barriers, which are distributed extensively along the world's coastlines. Scientists accept the idea that barrier islands, including other barrier types, can form by a number of different mechanisms. There appears to be some general requirements for formation. Barrier island systems develop most easily on wave-dominated coasts with a small to moderate tidal range. Coasts are classified into three groups based on tidal range: microtidal, 0–2 meter tidal range; mesotidal, 2–4 meter tidal range; and macrotidal, >4 meter tidal range. Barrier islands tend to form primarily along microtidal coasts, where they tend to be well developed and nearly continuous. They are less frequently formed in mesotidal coasts, where they are typically short with tidal inlets common. Barrier islands are very rare along macrotidal coasts. Along with a small tidal range and a wave-dominated coast, there must be a relatively low gradient shelf. Otherwise, sand accumulation into a sandbar would not occur and instead would be dispersed throughout the shore. An ample sediment supply is also


id: barrier-island-20260505-3
file: data/en.wikipedia.org/wiki/Barrier_island-3.md
category: reference
title: Barrier island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Barrier_island
date_saved: 2026-05-05T07:34:21.177659+00:00
instance: kb-cron
parent: barrier-island-20260505-0
summary:
=== Wave-dominated === Wave-dominated barrier islands are long, low, and narrow, and usually are bounded by unstable inlets at either end. The presence of longshore currents caused by waves approaching the island at an angle will carry sediment long, extending the island. Longshore currents, and the resultant extension, are usually in one direction, but in some circumstances the currents and extensions can occur towards both ends of the island (as occurs on Anclote Key, Three Rooker Bar, and Sand Key, on the Gulf Coast of Florida). Washover fans on the lagoon side of barriers, where storm surges have over-topped the island, are common, especially on younger barrier islands. Wave-dominated barriers are also susceptible to being breached by storms, creating new inlets. Such inlets may close as sediment is carried in them by longshore currents, but may become permanent if the tidal prism (volumn and force of tidal flow) is large enough. Older barrier islands that have accumulated dunes are less subject to washovers and opening of inlets. Wave-dominated islands require an abundant supply of sediment to grow and develop dunes. If a barrier island does not receive enough sediment to grow, repeated washovers from storms will migrate the island towards


id: bay-20260505-0
file: data/en.wikipedia.org/wiki/Bay-0.md
category: reference
title: Bay
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bay
date_saved: 2026-05-05T07:34:23.463029+00:00
instance: kb-cron
parent: bay-20260505-0
summary:
A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a gulf, sea, sound, or bight. A cove is a small, circular bay with a narrow entrance. A fjord is an elongated bay formed by glacial action. The term embayment is also used for related features, such as extinct bays or freshwater environments. A bay can be the estuary of a river, such as the Chesapeake Bay, an estuary of the Susquehanna River. Bays may also be nested within each other; for example, James Bay is an arm of Hudson Bay in northeastern Canada. Some bays are large enough to have varied marine geology, such as the Bay of Bengal (2,600,000 km2 or 1,000,000 sq mi) and Hudson Bay (1,230,000 km2 or 470,000 sq mi). The land surrounding a bay often reduces the strength of winds and blocks waves. Bays may have as wide a variety of shoreline characteristics as other shorelines. In some cases, bays have beaches, which "are usually characterized by a steep upper foreshore with a broad, flat fronting terrace". Bays were significant


id: beach-20260505-0
file: data/en.wikipedia.org/wiki/Beach-0.md
category: reference
title: Beach
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach
date_saved: 2026-05-05T07:34:24.791061+00:00
instance: kb-cron
parent: beach-20260505-0
summary:
A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shells or coralline algae. Sediments settle in different densities and structures, depending on the local wave action and weather, creating different textures, colors and gradients or layers of material. Though some beaches form on inland freshwater locations such as lakes and rivers, most beaches are in coastal areas where wave or current action deposits and reworks sediments. Erosion and changing of beach geologies happens through natural processes, like wave action and extreme weather events. Where wind conditions are correct, beaches can be backed by coastal dunes which offer protection and regeneration for the beach. However, these natural forces have become more extreme due to climate change, permanently altering beaches at very rapid rates. Some estimates describe as much as 50 percent of the earth's sandy beaches disappearing by 2100 due to climate-change driven sea level rise. Sandy beaches occupy about one third of global coastlines. These beaches are popular for recreation, playing important economic and cultural roles—often driving local tourism industries. To


id: beach-20260505-1
file: data/en.wikipedia.org/wiki/Beach-1.md
category: reference
title: Beach
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach
date_saved: 2026-05-05T07:34:24.791061+00:00
instance: kb-cron
parent: beach-20260505-0
summary:
Beaches are the result of wave action by which waves or currents move sand or other loose sediments of which the beach is made as these particles are held in suspension. Alternatively, sand may be moved by saltation (a bouncing movement of large particles). Beach materials come from erosion of rocks offshore, as well as from headland erosion and slumping producing deposits of scree. A coral reef offshore is a significant source of sand particles. Some species of fish that feed on algae attached to coral outcrops and rocks can create substantial quantities of sand particles over their lifetime as they nibble during feeding, digesting the organic matter, and discarding the rock and coral particles which pass through their digestive tracts. The composition of the beach depends upon the nature and quantity of sediments upstream of the beach, and the speed of flow and turbidity of water and wind. Sediments are moved by moving water and wind according to their particle size and state of compaction. Particles tend to settle and compact in still water. Once compacted, they are more resistant to erosion. Established vegetation (especially species with complex network root systems) will resist erosion by slowing the fluid flow


id: beach-20260505-2
file: data/en.wikipedia.org/wiki/Beach-2.md
category: reference
title: Beach
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach
date_saved: 2026-05-05T07:34:24.791061+00:00
instance: kb-cron
parent: beach-20260505-0
summary:
==== Causes ==== Beaches are changed in shape chiefly by the movement of water and wind. Any weather event that is associated with turbid or fast-flowing water or high winds will erode exposed beaches. Longshore currents will tend to replenish beach sediments and repair storm damage. Tidal waterways generally change the shape of their adjacent beaches by small degrees with every tidal cycle. Over time these changes can become substantial leading to significant changes in the size and location of the beach. ==== Effects on flora ==== Changes in the shape of the beach may undermine the roots of large trees and other flora. Many beach adapted species (such as coconut palms) have a fine root system and large root ball which tends to withstand wave and wind action and tends to stabilize beaches better than other trees with a lesser root ball. ==== Effects on adjacent land ==== Erosion of beaches can expose less resilient soils and rocks to wind and wave action leading to undermining of coastal headlands eventually resulting in catastrophic collapse of large quantities of overburden into the shallows. This material may be distributed along the beach front leading to a change in the habitat as


id: beach-20260505-3
file: data/en.wikipedia.org/wiki/Beach-3.md
category: reference
title: Beach
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach
date_saved: 2026-05-05T07:34:24.791061+00:00
instance: kb-cron
parent: beach-20260505-0
summary:
==== Concentration of runoff ==== Beaches provide a filter for runoff from the coastal plain. If the runoff is naturally dispersed along the beach, water borne silt and organic matter will be retained on the land and will feed the flora in the coastal area. Runoff that is dispersed along the beach will tend to percolate through the beach and may emerge from the beach at low tide. The retention of the freshwater may also help to maintain underground water reserves and will resist salt water incursion. If the surface flow of the runoff is diverted and concentrated by drains that create constant flows over the beach above the sea or river level, the beach will be eroded and ultimately form an inlet unless longshore flows deposit sediments to repair the breach. Once eroded, an inlet may allow tidal inflows of salt water to pollute areas inland from the beach and may also affect the quality of underground water supplies and the height of the water table. ==== Deprivation of runoff ==== Some flora naturally occurring on the beach head requires freshwater runoff from the land. Diversion of freshwater runoff into drains may deprive these plants of their water supplies


id: beach-20260505-4
file: data/en.wikipedia.org/wiki/Beach-4.md
category: reference
title: Beach
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach
date_saved: 2026-05-05T07:34:24.791061+00:00
instance: kb-cron
parent: beach-20260505-0
summary:
The extension of this form of leisure to the middle and working classes began with the development of the railways in the 1840s, which offered cheap fares to fast-growing resort towns. In particular, the completion of a branch line to the small seaside town of Blackpool from Poulton led to a sustained economic and demographic boom. A sudden influx of visitors, arriving by rail, led entrepreneurs to build accommodation and create new attractions, leading to more visitors and a rapid cycle of growth throughout the 1850s and 1860s. The growth was intensified by the practice among the Lancashire cotton mill owners of closing the factories for a week every year to service and repair machinery. These became known as wakes weeks. Each town's mills would close for a different week, allowing Blackpool to manage a steady and reliable stream of visitors over a prolonged period in the summer. A prominent feature of the resort was the promenade and the pleasure piers, where an eclectic variety of performances vied for the people's attention. In 1863, the North Pier in Blackpool was completed, rapidly becoming a centre of attraction for upper class visitors. Central Pier was completed in 1868, with a theatre


id: beach-20260505-5
file: data/en.wikipedia.org/wiki/Beach-5.md
category: reference
title: Beach
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach
date_saved: 2026-05-05T07:34:24.791061+00:00
instance: kb-cron
parent: beach-20260505-0
summary:
=== Artificial beaches === Some beaches are artificial; they are either permanent or temporary (For examples, see Copenhagen, Hong Kong, Manila, Monaco, Nottingham, Paris, Rotterdam, Singapore, Tianjin, and Toronto). The soothing qualities of a beach and the pleasant environment offered to the beachgoer are replicated in artificial beaches, such as "beach style" pools with zero-depth entry and wave pools that recreate the natural waves pounding upon a beach. In a zero-depth entry pool, the bottom surface slopes gradually from above water down to depth. Another approach involves so-called urban beaches, a form of public park becoming common in large cities. Urban beaches attempt to mimic natural beaches with fountains that imitate surf and mask city noises, and in some cases can be used as a play park. Beach nourishment involves pumping sand onto beaches to improve their health. Beach nourishment is common for major beach cities around the world; however the beaches that have been nourished can still appear quite natural and often many visitors are unaware of the works undertaken to support the health of the beach. Such beaches are often not recognized by consumers as artificial. A famous example of beach nourishment came with the replenishment of Waikīkī


id: beach-20260505-6
file: data/en.wikipedia.org/wiki/Beach-6.md
category: reference
title: Beach
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach
date_saved: 2026-05-05T07:34:24.791061+00:00
instance: kb-cron
parent: beach-20260505-0
summary:
=== Corduroy (beach ladder) === A corduroy road or beach ladder (or board and chain) is an array of planks (usually hardwood or treated timber) laid close together and perpendicular to the direction of traffic flow, and secured at each end by a chain or cable to form a pathway or ramp over the sand dune. Corduroys are cheap and easy to construct and quick to deploy or relocate. They are commonly used for pedestrian access paths and light duty vehicular access ways. They naturally conform to the shape of the underlying beach or dune profile, and adjust well to moderate erosion, especially longshore drift. However, they can cease to be an effective access surface if they become buried or undermined by erosion by surface runoff coming from the beach head. If the corduroy is not wide enough for vehicles using it, the sediment on either side may be displaced creating a spoon drain that accelerates surface runoff and can quickly lead to serious erosion. Significant erosion of the sediment beside and under the corduroy can render it completely ineffective and make it dangerous to pedestrian users who may fall between the planks. === Fabric ramp === Fabric ramps are


id: beach-evolution-20260505-0
file: data/en.wikipedia.org/wiki/Beach_evolution-0.md
category: reference
title: Beach evolution
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach_evolution
date_saved: 2026-05-05T07:34:26.041541+00:00
instance: kb-cron
parent: beach-evolution-20260505-0
summary:
Beach evolution is a natural process occurring along shorelines where sea, lake, or river water erodes the land. Beaches form as sand accumulates over centuries through recurrent processes that erode rocky and sedimentary material into sand deposits. River deltas contribute by depositing silt carried from upriver, accreting at the river's outlet to extend lake or ocean shorelines. Catastrophic events such as tsunamis, hurricanes, and storm surges accelerate beach evolution. == Accretion and erosion == === Sudden and rapid processes === ==== Tsunamis and hurricane-driven storm surges ==== Tsunamis can cause significant erosion and sediment displacement. They can strip away years of accumulated sand from beaches and devastate coastal vegetation. These powerful waves can flood inland areas far beyond the typical high-tide mark. Additionally, the swift currents associated with the inundating tsunami can demolish homes and other coastal structures. A storm surge is an onshore gush of water associated with a low pressure weather system. Storm surges can cause beach accretion and erosion. Historically notable storm surges occurred during the North Sea Flood of 1953, Hurricane Katrina, and the 1970 Bhola cyclone. ==== Volcanism and earthquakes related sea-level changes ==== Both geological events and the climate can change (progressively or suddenly)


id: beach-evolution-20260505-1
file: data/en.wikipedia.org/wiki/Beach_evolution-1.md
category: reference
title: Beach evolution
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach_evolution
date_saved: 2026-05-05T07:34:26.041541+00:00
instance: kb-cron
parent: beach-evolution-20260505-0
summary:
Abandonment of shore: do nothing, let the natural process takeover. Managed retreat, also called realignment. Hold the shoreline: by using shoreline hardening techniques to create permanent concrete and rock constructions such as groynes. Move beach seaward: by using hard and soft intervention techniques usually in areas of high economic significance. Limited intervention: usually in areas of low economic significance, often includes the succession of haloseres, including salt marshes and sand dunes. === Coastal engineering === Coastal engineering techniques can be classified into two categories: hard engineering methods and soft engineering methods ==== Hard engineering methods ==== Hard engineering methods are also called "Structural methods". "Move towards the sea" beach accretion can be facilitated by the four main type of hard engineering structures, namely seawall, revetment, groyne or breakwater. Most commonly used hard structures are seawall and series of "headland groyne" (breakwater connected to the shore with groyne). ===== Main types of structures ===== Four main types of structures or accropodes are seawalls, groynes, breakwater and revetments. Headland groynes are a combination of breakwater and groyne. ====== Seawalls ====== Seawalls re-direct most of the incident energy in the form of sloping revetments, resulting in low reflected waves and much reduced turbulence.


id: beach-evolution-20260505-2
file: data/en.wikipedia.org/wiki/Beach_evolution-2.md
category: reference
title: Beach evolution
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach_evolution
date_saved: 2026-05-05T07:34:26.041541+00:00
instance: kb-cron
parent: beach-evolution-20260505-0
summary:
====== Concrete objects ====== These are complex reinforced concrete objects, such as A-jack, Akmon, Dolos, Honeycomb sea wall (Seabees), KOLOS, Tetrapod and Xbloc. Simple concrete blocks have been replaced by these complex concrete objects because these objects are more resistant to wave action and require less concrete to produce a superior result. These could be used to build seawalls, groynes, breakwaters, and other structures including residential buildings. Tetrapods used along Marine Drive, Mumbai are an example of complex concrete objects. ====== Gabions ====== Gabions are constructed by wiring boulders and rocks into mesh cages and placed in front of areas vulnerable to erosion, sometimes at cliffs edges or at right angles to the beach. When the ocean lands on the gabion, the water drains through leaving sediment, while the structure absorbs a moderate amount of wave energy. Gabions need to be securely tied to protect the structure. They can be used to build seawalls, groynes, breakwaters, revetments, buildings, underwater reefs, etc., ==== Soft engineering methods ==== Soft engineering uses a "soft" (non-permanent) structure by creating a larger sand reservoir, pushing the shoreline seaward. It gained popularity because it preserved beach resources and avoided the negative effects of hard structures. =====


id: beach-evolution-20260505-3
file: data/en.wikipedia.org/wiki/Beach_evolution-3.md
category: reference
title: Beach evolution
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach_evolution
date_saved: 2026-05-05T07:34:26.041541+00:00
instance: kb-cron
parent: beach-evolution-20260505-0
summary:
This Integrated coastal zone management example is based on the "move beach seaward" general planning approach which involves both hard and soft engineering methods. This scenario minimizes the maintenance effort and cost by making optimal use of the coastal geography by incorporating natural coastal geographical features in the engineering design. The cost is kept low by the use of easily available free or cost-effective local material, use of which is already known to or easily acquired by the local workforce. This solution entails beach nourishment (creating recreational area by filling with sand), and further beach expansion and prevention of beach erosion caused by longshore drift and coastal development hazards. The design makes use of a shorter groyne slightly inclined toward the beach in the same direction as downdrift, with a series of "headland groyne" perpendicular to the shore, and a longer "headland groyne" at the end of downdrift side of the beach with smaller "headland groyne" perpendicular to it facing the updrift end of the beach. This example of tropical setting, part of the sea could be reclaimed by building a seawall with revetment (slope) fortified with armament of honeycomb seebee made of concrete with hexagonal holes, parts of seawall


id: beach-evolution-20260505-4
file: data/en.wikipedia.org/wiki/Beach_evolution-4.md
category: reference
title: Beach evolution
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beach_evolution
date_saved: 2026-05-05T07:34:26.041541+00:00
instance: kb-cron
parent: beach-evolution-20260505-0
summary:
==== California beaches ==== California's beaches and other shoreline features change according to the availability of beach sand, the wave and current energy impinging on the coast, and other physical processes that affect the movement of sand. A constant supply of sand is necessary for beaches to form and be maintained along this shoreline. Many human activities, including dam construction and river channelization, have reduced the supply of sand that reaches the ocean. This, in turn, has prevented beaches from being replenished and has thus created greater vulnerability for shorelines that have always been subject to varying levels of erosion. There are few practical solutions to improving sand supply from inland sources, so management of shoreline erosion will likely continue to focus at the land/sea interface along the California coastline. Construction of breakwaters, jetties, or groyne fields to protect harbor entrances, maintain beaches, or protect coastal structures have both helped and harmed the movement of sand along the shoreline. Protective armoring formations trap sand and allow beaches to expand up-coast from the device, but can interrupt the flow of sand to beaches located down-coast. ==== France ==== ===== Atlantic coast ===== Some of the coastal defence bunkers of the Atlantic


id: beachrock-20260505-0
file: data/en.wikipedia.org/wiki/Beachrock-0.md
category: reference
title: Beachrock
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Beachrock
date_saved: 2026-05-05T07:34:27.242877+00:00
instance: kb-cron
parent: beachrock-20260505-0
summary:
Beachrock is a friable to well-cemented sedimentary rock that consists of a variable mixture of gravel-, sand-, and silt-sized sediment that is cemented with carbonate minerals and has formed along a shoreline. Depending on location, the sediment that is cemented to form beachrock can consist of a variable mixture of shells, coral fragments, rock fragments of different types, and other materials. It can also contain scattered artifacts, pieces of wood, and coconuts. Beachrock typically forms within the intertidal zone within tropical or semitropical regions. However, Quaternary beachrock is also found as far north and south as 60° latitude. == Overview == Beachrock units form under a thin cover of sediment and generally overlie unconsolidated sand. They typically consist of multiple units, representing multiple episodes of cementation and exposure. The mineralogy of beachrocks is mainly high-magnesium calcite or aragonite. The main processes involved in the cementation are : supersaturation with CaCO3 through direct evaporation of seawater, groundwater CO2 degassing in the vadose zone, mixing of marine and meteoric water fluxes and precipitation of micritic calcium carbonate as a byproduct of microbiological activity. On retreating coasts, outcrops of beachrock may be evident offshore where they may act as a barrier against coastal


id: benthic-zone-20260505-0
file: data/en.wikipedia.org/wiki/Benthic_zone-0.md
category: reference
title: Benthic zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Benthic_zone
date_saved: 2026-05-05T07:34:28.462475+00:00
instance: kb-cron
parent: benthic-zone-20260505-0
summary:
The benthic zone, from Ancient Greek βένθος (bénthos) 'the depths of the ocean', is the ecological region at the lowest level of a body of water, such as a stream, river, lake, or ocean, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos, or more informally bottom dwellers. They include microorganisms such as bacteria and fungi, as well as larger invertebrates such as crustaceans and polychaetes. Benthos generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. == Physical description == === Oceans === The benthic region of the ocean begins at the shore line (intertidal or littoral zone) and extends downward along the surface of the continental shelf out to sea. Thus, the region incorporates a great variety of physical conditions differing in depth, light penetration and pressure. The benthic


id: benthic-zone-20260505-1
file: data/en.wikipedia.org/wiki/Benthic_zone-1.md
category: reference
title: Benthic zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Benthic_zone
date_saved: 2026-05-05T07:34:28.462475+00:00
instance: kb-cron
parent: benthic-zone-20260505-0
summary:
Benthos is the community of organisms that live in the benthic zone, that is, on, in, or near the bottom of a stream, river, lake, or ocean. This community lives in or near marine or freshwater sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths. The term benthos, coined by Haeckel in 1891, comes from the Greek noun βένθος 'depth of the ocean'. Additionally to oceans, benthos is also used in freshwater biology to refer to organisms at the bottom of freshwater bodies of water, such as streams, rivers, and lakes. There is also a redundant, occasionally used synonym, benthon. Benthos is also referred to more loosely and informally as bottom dwellers or bottom feeders. Light is an important energy source for shallow benthic systems. However, because light is absorbed before it can reach deep ocean water, the energy source for deep benthic ecosystems is often organic matter from higher up in the water column that drifts down to the depths. This dead and decaying matter sustains the benthic food chain; most organisms in the benthic zone are scavengers or detritivores. Many organisms adapted to deep-water pressure cannot survive


id: benthic-zone-20260505-2
file: data/en.wikipedia.org/wiki/Benthic_zone-2.md
category: reference
title: Benthic zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Benthic_zone
date_saved: 2026-05-05T07:34:28.462475+00:00
instance: kb-cron
parent: benthic-zone-20260505-0
summary:
Both foraminifera and diatoms have planktonic and benthic forms, that is, they can drift in the water column or live on sediment at the bottom of the ocean. Regardless of form, their shells sink to the seafloor after they die. These shells are widely used as climate proxies. The chemical composition of the shells are a consequence of the chemical composition of the ocean at the time the shells were formed. Past water temperatures can be also be inferred from the ratios of stable oxygen isotopes in the shells, since lighter isotopes evaporate more readily in warmer water leaving the heavier isotopes in the shells. Information about past climates can be inferred further from the abundance of forams and diatoms, since they tend to be more abundant in warm water.The sudden extinction event which killed the dinosaurs 66 million years ago also rendered extinct three-quarters of all other animal and plant species. However, deep-sea benthic forams flourished in the aftermath. In 2020 it was reported that researchers have examined the chemical composition of thousands of samples of these benthic forams and used their findings to build the most detailed climate record of Earth ever. Some endoliths have extremely long lives.


id: benthic-zone-20260505-3
file: data/en.wikipedia.org/wiki/Benthic_zone-3.md
category: reference
title: Benthic zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Benthic_zone
date_saved: 2026-05-05T07:34:28.462475+00:00
instance: kb-cron
parent: benthic-zone-20260505-0
summary:
=== Nutrient flux === Sources of food for benthic communities can derive from the water column above these habitats in the form of aggregations of detritus, inorganic matter, and living organisms. These aggregations are commonly referred to as marine snow, and are important for the deposition of organic matter, and bacterial communities. The amount of material sinking to the ocean floor can average 307,000 aggregates per m2 per day. This amount will vary on the depth of the benthos, and the degree of benthic-pelagic coupling. The benthos in a shallow region will have more available food than the benthos in the deep sea. Because of their reliance on it, microbes may become spatially dependent on detritus in the benthic zone. The microbes found in the benthic zone, specifically dinoflagellates and foraminifera, colonize quite rapidly on detritus matter while forming a symbiotic relationship with each other. In the deep sea, which covers 90–95% of the ocean floor, 90% of the total biomass is made up of prokaryotes. To release all the nutrients locked inside these microbes to the environment, viruses are important in making it available to other organisms. The main food sources for the benthos are phytoplankton and organic detrital


id: benthic-zone-20260505-4
file: data/en.wikipedia.org/wiki/Benthic_zone-4.md
category: reference
title: Benthic zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Benthic_zone
date_saved: 2026-05-05T07:34:28.462475+00:00
instance: kb-cron
parent: benthic-zone-20260505-0
summary:
Benthic macroinvertebrates have many important ecological functions, such as regulating the flow of materials and energy in river ecosystems through their food web linkages. Because of this correlation between flow of energy and nutrients, benthic macroinvertebrates have the ability to influence food resources on fish and other organisms in aquatic ecosystems. For example, the addition of a moderate amount of nutrients to a river over the course of several years resulted in increases in invertebrate richness, abundance, and biomass. These in turn resulted in increased food resources for native species of fish with insignificant alteration of the macroinvertebrate community structure and trophic pathways. The presence of macroinvertebrates such as Amphipoda also affect the dominance of certain types of algae in Benthic ecosystems as well. In addition, because benthic zones are influenced by the flow of dead organic material, there have been studies conducted on the relationship between stream and river water flows and the resulting effects on the benthic zone. Low flow events show a restriction in nutrient transport from benthic substrates to food webs, and caused a decrease in benthic macroinvertebrate biomass, which lead to the disappearance of food sources into the substrate. Because the benthic system regulates energy


id: cape-geography-20260505-0
file: data/en.wikipedia.org/wiki/Cape_(geography)-0.md
category: reference
title: Cape (geography)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cape_(geography)
date_saved: 2026-05-05T07:34:31.991235+00:00
instance: kb-cron
parent: cape-geography-20260505-0
summary:
In geography, a cape is a headland, peninsula or promontory extending into a body of water, usually a sea. A cape usually represents a marked change in trend of the coastline, often making them important landmarks in sea navigation. This also makes them prone to natural forms of erosion, mainly tidal actions, resulting in a relatively short geological lifespan. == Formation == Capes can be formed by glaciers, volcanoes, and changes in sea level. Erosion plays a large role in each of these methods of formation. Coastal erosion by waves and currents can create capes by wearing away softer rock and leaving behind harder rock formations. Movements of the Earth's crust can uplift land, forming capes. For example, the Cape of Good Hope was formed by tectonic forces. Volcanic eruptions can create capes by depositing lava that solidifies into new landforms. Cape Verde, (also known as Cabo Verde) is an example of a volcanic cape. Glaciers can carve out capes by eroding the landscape as they advance and retreat. Cape Cod in the United States was formed by glacial activity during the last Ice Age. == Importance in navigation == Capes (and other headlands) are conspicuous visual landmarks along a


id: capillary-wave-20260505-0
file: data/en.wikipedia.org/wiki/Capillary_wave-0.md
category: reference
title: Capillary wave
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Capillary_wave
date_saved: 2026-05-05T07:34:33.305688+00:00
instance: kb-cron
parent: capillary-wave-20260505-0
summary:
A capillary wave is a wave traveling along the phase boundary of a fluid, whose dynamics and phase velocity are dominated by the effects of surface tension. Capillary waves are common in nature, and are often referred to as ripples. The wavelength of capillary waves on water is typically less than a few centimeters, with a phase speed in excess of 0.2–0.3 meter/second. A longer wavelength on a fluid interface will result in gravity–capillary waves which are influenced by both the effects of surface tension and gravity, as well as by fluid inertia. Ordinary gravity waves have a still longer wavelength. Light breezes upon the surface of water which stir up such small ripples are also sometimes referred to as 'cat's paws'. On the open ocean, much larger ocean surface waves (seas and swells) may result from coalescence of smaller wind-caused ripple-waves. == Dispersion relation == The dispersion relation describes the relationship between wavelength and frequency in waves. Distinction can be made between pure capillary waves – fully dominated by the effects of surface tension – and gravity–capillary waves which are also affected by gravity. === Capillary waves, proper === The dispersion relation for capillary waves is ω 2 =


id: capillary-wave-20260505-1
file: data/en.wikipedia.org/wiki/Capillary_wave-1.md
category: reference
title: Capillary wave
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Capillary_wave
date_saved: 2026-05-05T07:34:33.305688+00:00
instance: kb-cron
parent: capillary-wave-20260505-0
summary:
==== Derivation ==== As Richard Feynman put it, "[water waves] that are easily seen by everyone and which are usually used as an example of waves in elementary courses [...] are the worst possible example [...]; they have all the complications that waves can have." The derivation of the general dispersion relation is therefore quite involved. There are three contributions to the energy, due to gravity, to surface tension, and to hydrodynamics. The first two are potential energies, and responsible for the two terms inside the parenthesis, as is clear from the appearance of g {\displaystyle g} and σ {\displaystyle \sigma } . For gravity, an assumption is made of the density of the fluids being constant (i.e., incompressibility), and likewise g {\displaystyle g} (waves are not high enough for gravitation to change appreciably). For surface tension, the deviations from planarity (as measured by derivatives of the surface) are supposed to be small. For common waves both approximations are good enough. The third contribution involves the kinetic energies of the fluids. It is the most complicated and calls for a hydrodynamic framework. Incompressibility is again involved (which is satisfied if the speed of the waves is much less than the


id: coast-20260505-0
file: data/en.wikipedia.org/wiki/Coast-0.md
category: reference
title: Coast
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coast
date_saved: 2026-05-05T07:34:34.633460+00:00
instance: kb-cron
parent: coast-20260505-0
summary:
A coast (also called the coastline, shoreline, or seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, such as that caused by waves. The geological composition of rock and soil dictates the type of shore that is created. Earth has about 620,000.0 km (385,250.1 mi) of coastline. Coasts are important zones in natural ecosystems, often home to a wide range of biodiversity. On land, they harbor ecosystems, such as freshwater or estuarine wetlands, that are important for birds and other terrestrial animals. In wave-protected areas, coasts harbor salt marshes, mangroves, and seagrasses, all of which can provide nursery habitat for finfish, shellfish, and other aquatic animals. Rocky shores are usually found along exposed coasts and provide habitat for a wide range of sessile animals (e.g. mussels, starfish, barnacles) and various kinds of seaweeds. In physical oceanography, a shore is the wider fringe that is geologically modified by the action of the body of water past and present, and the beach is at the edge of the shore, including the intertidal zone


id: coast-20260505-1
file: data/en.wikipedia.org/wiki/Coast-1.md
category: reference
title: Coast
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coast
date_saved: 2026-05-05T07:34:34.633460+00:00
instance: kb-cron
parent: coast-20260505-0
summary:
Tides often determine the range over which sediment is deposited or eroded. Areas with high tidal ranges allow waves to reach farther up the shore, and areas with lower tidal ranges produce deposition at a smaller elevation interval. The tidal range is influenced by the size and shape of the coastline. Tides do not typically cause erosion by themselves; however, tidal bores can erode as the waves surge up the river estuaries from the ocean. Geologists classify coasts on the basis of tidal range into macrotidal coasts with a tidal range greater than 4 m (13 ft); mesotidal coasts with a tidal range of 2 to 4 m (6.6 to 13 ft); and microtidal coasts with a tidal range of less than 2 m (7 ft). The distinction between macrotidal and mesotidal coasts is more important. Macrotidal coasts lack barrier islands and lagoons, and are characterized by funnel-shaped estuaries containing sand ridges aligned with tidal currents. Wave action is much more important for determining bedforms of sediments deposited along mesotidal and microtidal coasts than in macrotidal coasts. Waves erode coastline as they break on shore releasing their energy; the larger the wave the more energy it releases and the more


id: coast-20260505-2
file: data/en.wikipedia.org/wiki/Coast-2.md
category: reference
title: Coast
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coast
date_saved: 2026-05-05T07:34:34.633460+00:00
instance: kb-cron
parent: coast-20260505-0
summary:
==== Destructive and constructive waves ==== Swash is the shoreward flow after the break, backwash is the water flow back down the beach. The relative strength of flow in the swash and backwash determines what size grains are deposited or eroded. This is dependent on how the wave breaks and the slope of the shore. Depending on the form of the breaking wave, its energy can carry granular material up the beach and deposit it, or erode it by carrying more material down the slope than up it. Steep waves that are close together and break with the surf plunging down onto the shore slope expend much of their energy lifting the sediment. The weak swash does not carry it far up the slope, and the strong backwash carries it further down the slope, where it either settles in deeper water or is carried along the shore by a longshore current induced by an angled approach of the wave-front to the shore. These waves which erode the beach are called destructive waves. Low waves that are further apart and break by spilling, expend more of their energy in the swash which carries particles up the beach, leaving less energy for


id: coast-20260505-3
file: data/en.wikipedia.org/wiki/Coast-3.md
category: reference
title: Coast
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coast
date_saved: 2026-05-05T07:34:34.633460+00:00
instance: kb-cron
parent: coast-20260505-0
summary:
"Coastal waters" (or "coastal seas") is a term that carries different meanings depending upon the context, ranging from a geographic reference to the waters within a few kilometers of the coast, to describing the entire continental shelf that may stretch for more than a hundred kilometers from land. The term is used in a different manner when describing legal and economic boundaries, such as territorial waters and international waters, or when describing the geography of coastal landforms or the ecological systems operating through the continental shelf (marine coastal ecosystems). The dynamic fluid nature of the ocean means that all components of the whole ocean system are ultimately connected, although certain regional classifications are useful and relevant. The waters of the continental shelves represent such a region. The term "coastal waters" has been used in a wide variety of different ways in different contexts. In European Union environmental management it extends from the coast to just a few nautical miles while in the United States the US EPA considers this region to extend much further offshore. "Coastal waters" has specific meanings in the context of commercial coastal shipping, and somewhat different meanings in the context of naval littoral warfare. Oceanographers and


id: cold-seep-20260505-0
file: data/en.wikipedia.org/wiki/Cold_seep-0.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
A cold seep (sometimes called a cold vent) is an area of the ocean floor where seepage of fluids rich in hydrogen sulfide, methane, and other hydrocarbons occurs, often in the form of a brine pool. Cold does not mean that the temperature of the seepage is lower than that of the surrounding sea water; on the contrary, its temperature is often slightly higher. The "cold" is relative to the very warm (at least 60 °C or 140 °F) conditions of a hydrothermal vent. Cold seeps constitute a biome supporting several endemic species. Cold seeps develop unique topography over time, where reactions between methane and seawater create carbonate rock formations and reefs. These reactions may also be dependent on bacterial activity. Ikaite, a hydrous calcium carbonate, can be associated with oxidizing methane at cold seeps. == Types == Types of cold seeps can be distinguished according to the depth, as shallow cold seeps and deep cold seeps. Cold seeps can also be distinguished in detail, as follows: oil/gas seeps gas seeps: methane seeps gas hydrate seeps brine seeps are formed in brine pools pockmarks mud volcanoes == Formation and ecological succession == Cold seeps occur over fissures on the seafloor


id: cold-seep-20260505-1
file: data/en.wikipedia.org/wiki/Cold_seep-1.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
=== The Benthic Filter === The organisms living at cold seeps have a large impact on the carbon cycle and on climate. Chemosynthetic organisms, specifically methanogenic (methane-consuming) organisms, prohibit the methane seeping up from beneath the seafloor from being released into the water above. Since methane is such a potent greenhouse gas, methane release could cause global warming when gas hydrate reservoirs destabilized. The consumption of methane by aerobic and anaerobic seafloor life is called "the benthic filter". The first part of this filter is the anaerobic bacteria and archaea underneath the seafloor that consume methane through the anaerobic oxidation of methane (AOM). If the flux of methane flowing through the sediment is too large, and the anaerobic bacteria and archaea are consuming the maximum amount of methane, then the excess methane is consumed by free-floating or symbiotic aerobic bacteria above the sediment at the seafloor. The symbiotic bacteria have been found in organisms such as tube worms and clams living at cold seeps; these organisms provide oxygen to the aerobic bacteria as the bacteria provide energy they obtain from the consumption of methane. Understanding how efficient the benthic filter is can help predict how much methane escapes the seafloor


id: cold-seep-20260505-2
file: data/en.wikipedia.org/wiki/Cold_seep-2.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
==== Discoveries ==== The chemosynthetic communities of the Gulf of Mexico have been studied extensively since the 1990s, and communities first discovered on the upper slope are likely the best understood seep communities in the world. The history of the discovery of these remarkable animals has all occurred since the 1980s. Each major discovery was unexpected―from the first hydrothermal vent communities anywhere in the world to the first cold seep communities in the Gulf of Mexico. Communities were discovered in the eastern Gulf of Mexico in 1983 using the crewed submersible DSV Alvin, during a cruise investigating the bottom of the Florida Escarpment in areas of "cold" brine seepage, where they unexpectedly discovered tubeworms and mussels. Two groups fortuitously discovered chemosynthetic communities in the central Gulf of Mexico nearly concurrently in November and December 1984. During investigations in late December on the research vessel R/V Gyre cruise 84-G-12, by Texas A&M University, two bottom trawls were conducted to determine the effects of oil seepage on benthic ecology (until this investigation, all effects of oil seepage were assumed to be detrimental). Trawls unexpectedly recovered extensive collections of chemosynthetic organisms, including tubeworms and clams. a month earlier, LGL Ecological Research Associates was


id: cold-seep-20260505-3
file: data/en.wikipedia.org/wiki/Cold_seep-3.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
The widespread nature of Gulf of Mexico chemosynthetic communities was first documented during contracted investigations by the Geological and Environmental Research Group (GERG) of Texas A&M University for the Offshore Operators Committee. This survey remains the most widespread and comprehensive, although numerous additional communities have been documented since that time. Industry exploration for energy reserves in the Gulf of Mexico has also documented numerous new communities through a wide range of depths, including the deepest-known occurrence in the Central Gulf of Mexico in Alaminos Canyon Block 818 at a depth of 2,750 metres (9,020 feet). The occurrence of chemosynthetic organisms dependent on hydrocarbon seepage has been documented in water depths as shallow as 290 metres (950 feet) and as deep as 2,744 metres (9,003 feet). This depth range specifically places chemosynthetic communities in the deepwater region of the Gulf of Mexico, which is defined as water depths greater than 305 metres (1,001 feet). Chemosynthetic communities are not found on the continental shelf, although they do appear in the fossil record in water shallower than 200 metres (660 feet). One theory explaining this is that predation pressure has varied substantially over the time period involved (Callender and Powell 1999). More than


id: cold-seep-20260505-4
file: data/en.wikipedia.org/wiki/Cold_seep-4.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
==== Stability ==== According to Sassen (1997) the role of hydrates at chemosynthetic communities has been greatly underestimated. The biological alteration of frozen gas hydrates was first discovered during the MMS study entitled "Stability and Change in Gulf of Mexico Chemosynthetic Communities". It is hypothesized that the dynamics of hydrate alteration could play a major role as a mechanism for regulation of the release of hydrocarbon gases to fuel biogeochemical processes and could also play a substantial role in community stability. Recorded bottom-water temperature excursions of several degrees in some areas such as the Bush Hill site (4–5 °C at 500-metre (1,600-foot) depth) are believed to result in dissociation of hydrates, resulting in an increase in gas fluxes (MacDonald et al., 1994). Although not as destructive as the volcanism at vent sites of the mid-ocean ridges, the dynamics of shallow hydrate formation and movement will clearly affect sessile animals that form part of the seepage barrier. There is potential of a catastrophic event where an entire layer of shallow hydrate could break free of the bottom and considerably affect local communities of chemosynthetic fauna. At deeper depths (>1,000 metres (3,300 feet)), the bottom-water temperature is colder (by approximately 3 °C)


id: cold-seep-20260505-5
file: data/en.wikipedia.org/wiki/Cold_seep-5.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
MacDonald et al. (1990) has described four general community types. These are communities dominated by Vestimentiferan tube worms (Lamellibrachia c.f. barhami and Escarpia spp.), mytilid mussels (Seep Mytilid Ia, Ib, and III, and others), vesicomyid clams (Vesicomya cordata and Calyptogena ponderosa), and infaunal lucinid or thyasirid clams (Lucinoma sp. or Thyasira sp.). Bacterial mats are present at all sites visited to date. These faunal groups tend to display distinctive characteristics in terms of how they aggregate, the size of aggregations, the geological and chemical properties of the habitats in which they occur, and, to some degree, the heterotrophic fauna that occur with them. Many of the species found at these cold seep communities in the Gulf of Mexico are new to science and remain undescribed. Individual lamellibrachid tube worms, the longer of two taxa found at seeps, can reach lengths of 3 metres (9.8 feet) and live hundreds of years (Fisher et al., 1997; Bergquist et al., 2000). Growth rates determined from recovered marked tube worms have been variable, ranging from no growth of 13 individuals measured one year to a maximum growth of 9.6 cm/yr (3.8 in/yr) in a Lamellibrachia individual (MacDonald, 2002). Average growth rate was 2.19 cm/yr


id: cold-seep-20260505-6
file: data/en.wikipedia.org/wiki/Cold_seep-6.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
Cold-seep communities in the western Atlantic Ocean have also been described from a few dives on mud volcanoes and diapirs between 1,000 and 5,000 m (3,300–16,400 ft) depth in the Barbados accretionary prism area and from the Blake Ridge diapir off North Carolina. More recently, seep communities have been discovered in the eastern Atlantic, on a giant pockmark cluster in the Gulf of Guinea near the Congo deep channel, and also on other pockmarks of the Congo margin, Gabon margin and Nigeria margin and in the Gulf of Cádiz. The occurrence of chemosymbiotic biota in the extensive mud volcano fields of the Gulf of Cádiz was first reported in 2003. The chemosymbiotic bivalves collected from the mud volcanoes of the Gulf of Cadiz were reviewed in 2011. Cold seeps are also known from the Northern Atlantic Ocean, even ranging into the Arctic Ocean, off Canada and Norway. Extensive faunal sampling has been conducted from 400 and 3,300 m (1,300–10,800 ft) in the Atlantic Equatorial Belt from the Gulf of Mexico to the Gulf of Guinea including the Barbados accretionary prism, the Blake Ridge diapir, and in the Eastern Atlantic from the Congo and Gabon margins and the recently explored Nigeria


id: cold-seep-20260505-7
file: data/en.wikipedia.org/wiki/Cold_seep-7.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
=== In the Mediterranean === The first biological evidence for reduced environments in the Mediterranean Sea was the presence of Lucinidae and Vesicomyidae bivalve shells cored on the top of the Napoli mud volcano (33°43′52″N 24°40′52″E; "Napoli" is only a name of a seamount. It is located south of Crete), located at 1,900 m deep on the Mediterranean Ridge in the subduction zone of the African Plate. This was followed by the description of a new Lucinidae bivalve species, Lucinoma kazani, associated with bacterial endosymbionts. In the southeastern Mediterranean, communities of polychaetes and bivalves were also found associated with cold seeps and carbonates near Egypt and the Gaza Strip at depths of 500–800 m, but no living fauna was collected. The first in situ observations of extensive living chemosynthetic communities in the eastern Mediterranean Sea prompted cooperation between biologists, geochemists, and geologists. During submersible dives, communities comprising large fields of small bivalves (dead and alive), large siboglinid tube worms, isolated or forming dense aggregations, large sponges, and associated endemic fauna were observed in various cold seep habitats associated with carbonate crusts at 1,700–2,000 m depth. Two mud volcano fields were first explored, one along the Mediterranean Ridge, where most of


id: cold-seep-20260505-8
file: data/en.wikipedia.org/wiki/Cold_seep-8.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
==== New Zealand ==== Off the mainland coast of New Zealand, shelf-edge instability is enhanced in some locations by cold seeps of methane-rich fluids that likewise support chemosynthetic faunas and carbonate concretions. Dominant animals are tubeworms of the family Siboglinidae and bivalves of families Vesicomyidae and Mytilidae (Bathymodiolus). Many of its species appear to be endemic. Deep bottom trawling has severely damaged cold seep communities, and those ecosystems are threatened. Cold seeps are found at depths down to 2,000 m, and the topographic and chemical complexity of the habitats are not yet mapped. The scale of new-species discovery in these poorly-studied or unexplored ecosystems is likely to be high. === In the East Pacific === In the deep sea, the COMARGE project has studied the biodiversity patterns along and across the Chilean margin through a complexity of ecosystems such as methane seeps and oxygen minimum zones, reporting that such habitat heterogeneity may influence the biodiversity patterns of the local fauna. Seep fauna include bivalves of families Lucinidae, Thyasiridae, Solemyidae (Acharax sp.), and Vesicomyidae (Calyptogena gallardoi) and polychaetes (Lamellibrachia sp. and two other polychaete species). Furthermore, in these soft reduced sediments below the oxygen minimum zone off the Chilean margin, a


id: cold-seep-20260505-9
file: data/en.wikipedia.org/wiki/Cold_seep-9.md
category: reference
title: Cold seep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cold_seep
date_saved: 2026-05-05T07:34:36.156842+00:00
instance: kb-cron
parent: cold-seep-20260505-0
summary:
== Environmental impacts == Major threats that cold seep ecosystems and their communities face today are seafloor litter, chemical contaminants, and climate change. Seafloor litter alters the habitat by providing hard substrate where none was available before or by overlying the sediment, thereby inhibiting gas exchange and interfering with organisms on the bottom of the sea. Studies of marine litter in the Mediterranean include surveys of seabed debris on the continental shelf, slope, and bathyal plain. In most studies, plastic items accounted for much of the debris, sometimes as much as 90% or more of the total, owing to their ubiquitous use and poor degradability. Weapons and bombs have also been discarded at sea, and their dumping in open waters contributes to seafloor contamination. Another major threat to the benthic fauna is the presence of lost fishing gear, such as nets and longlines, which contribute to ghost fishing and can damage fragile ecosystems such as cold-water corals. Chemical contaminants such as persistent organic pollutants, toxic metals (e.g., Hg, Cd, Pb, Ni), radioactive compounds, pesticides, herbicides, and pharmaceuticals are also accumulating in deep-sea sediments. Topography (such as canyons) and hydrography (such as cascading events) play a major role in the transportation


id: continental-margin-20260505-0
file: data/en.wikipedia.org/wiki/Continental_margin-0.md
category: reference
title: Continental margin
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Continental_margin
date_saved: 2026-05-05T07:34:37.444285+00:00
instance: kb-cron
parent: continental-margin-20260505-0
summary:
A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. The continental margin consists of three different features: the continental rise, the continental slope, and the continental shelf. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. Continental margins constitute about 28% of the oceanic area. == Subzones == The continental shelf is the relatively shallow water area found in proximity to continents; it is the portion of the continental margin that transitions from the shore out towards the ocean. Continental shelves are believed to make up 7% of the sea floor. The width of continental shelves worldwide varies in the range of 0.03–1500 km. The continental shelf is generally flat, and ends at the shelf break, where there is a drastic increase in slope angle: The mean angle of continental shelves worldwide is 0° 07′, and typically steeper closer to the coastline than it is near the shelf break. At the shelf break begins the continental slope, which can be 1–5 km above the deep-ocean floor. The continental slope often exhibits features called submarine canyons. Submarine canyons often cut into the


id: continental-shelf-20260505-0
file: data/en.wikipedia.org/wiki/Continental_shelf-0.md
category: reference
title: Continental shelf
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Continental_shelf
date_saved: 2026-05-05T07:34:38.658115+00:00
instance: kb-cron
parent: continental-shelf-20260505-0
summary:
A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island is known as an "insular shelf." The continental margin, between the continental shelf and the abyssal plain, comprises a steep continental slope, surrounded by the flatter continental rise, in which sediment from the continent above cascades down the slope and accumulates as a pile of sediment at the base of the slope. Extending as far as 500 km (310 mi) from the slope, it consists of thick sediments deposited by turbidity currents from the shelf and slope. The continental rise's gradient is intermediate between the gradients of the slope and the shelf. Under the United Nations Convention on the Law of the Sea, the name continental shelf was given a legal definition as the stretch of the seabed adjacent to the shores of a particular country to which it belongs. == Topography == The shelf usually ends at a point of increasing slope (called the shelf break). The sea floor below the break is the continental slope.


id: continental-shelf-20260505-1
file: data/en.wikipedia.org/wiki/Continental_shelf-1.md
category: reference
title: Continental shelf
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Continental_shelf
date_saved: 2026-05-05T07:34:38.658115+00:00
instance: kb-cron
parent: continental-shelf-20260505-0
summary:
In shallower water with stronger tides and away from river mouths, tidal turbulence overcomes the stratifying influence of surface heating, and the water column remains well mixed for the entire seasonal cycle. In contrast, in deeper water, the surface heating wins out in summer, to produce seasonal stratification with a warm surface layer overlying the isolated deep water. (The well mixed and seasonally stratifying regimes are separated by persistent features called tidal mixing fronts.) A third regime which links estuaries to shelf seas, Regions of Freshwater Influence (ROFIs), is found where estuaries enter shelf seas, for example in the Liverpool Bay area of the Irish Sea and Rhine Outflow region of the North Sea. Here, stratification can vary on timescales from the semidiurnal tidal cycle through to the springs-neap tidal cycle due to a process known as "tidal straining". While the North Sea and Irish Sea are two of the better studied shelf seas, they are not necessarily representative of all shelf seas as there is a wide variety of behaviours to be found: Indian Ocean shelf seas are dominated by major river systems, including the Ganges and Indus rivers. The shelf seas around New Zealand are complicated because the


id: continental-shelf-20260505-2
file: data/en.wikipedia.org/wiki/Continental_shelf-2.md
category: reference
title: Continental shelf
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Continental_shelf
date_saved: 2026-05-05T07:34:38.658115+00:00
instance: kb-cron
parent: continental-shelf-20260505-0
summary:
== References == Atkinson, Larry P.; Lee, Thomas N.; Blanton, Jackson O.; Chandler, William S. (30 May 1983). "Climatology of the southeastern United States continental shelf waters". Journal of Geophysical Research: Oceans. 88 (C8): 4705–4718. Bibcode:1983JGR....88.4705A. doi:10.1029/JC088iC08p04705. de Haas, Henk; van Weering, Tjeerd C.E; de Stigter, Henko (March 2002). "Organic carbon in shelf seas: sinks or sources, processes and products". Continental Shelf Research. 22 (5): 691–717. Bibcode:2002CSR....22..691D. doi:10.1016/S0278-4343(01)00093-0. "shelf break – geology". Encyclopædia Britannica. Figueiredo, Alberto Garcia; Pacheco, Carlos Eduardo Pereira; de Vasconcelos, Sérgio Cadena; da Silva, Fabiano Tavares (2016). "Continental Shelf Geomorphology and Sedimentology". Geology and Geomorphology: 13–31. doi:10.1016/B978-85-352-8444-7.50009-3. ISBN 9788535284447. Gattuso, Jean-Pierre; Gentili, B.; Duarte, C. M.; Kleypas, J. A.; Middelburg, J. J.; Antoine, D. (2006). "Light availability in the coastal ocean: impact on the distribution of benthic photosynthetic organisms and their contribution to primary production". Biogeosciences. 3 (4). European Geosciences Union: 489–513. Bibcode:2006BGeo....3..489G. doi:10.5194/bg-3-489-2006. hdl:20.500.11937/23744. S2CID 13715554. hal-00330315. Retrieved 1 July 2021. Gross, M. Grant (1972). Oceanography: A View of the Earth. Englewood Cliffs: Prentice-Hall. ISBN 978-0-13-629659-1. Retrieved 12 January 2016. Guihou, K.; Polton, J.; Harle, J.; Wakelin, S.; O'Dea, E.; Holt, J. (January 2018). "Kilometric Scale Modeling of the North West European Shelf Seas: Exploring the


id: continental-shelf-pump-20260505-0
file: data/en.wikipedia.org/wiki/Continental_shelf_pump-0.md
category: reference
title: Continental shelf pump
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Continental_shelf_pump
date_saved: 2026-05-05T07:34:39.905353+00:00
instance: kb-cron
parent: continental-shelf-pump-20260505-0
summary:
In oceanic biogeochemistry, the continental shelf pump is proposed to operate in the shallow waters of the continental shelves, acting as a mechanism to transport carbon (as either dissolved or particulate material) from surface waters to the interior of the adjacent deep ocean. == Overview == Originally formulated by Tsunogai et al. (1999), the pump is believed to occur where the solubility and biological pumps interact with a local hydrography that feeds dense water from the shelf floor into sub-surface (at least subthermocline) waters in the neighbouring deep ocean. Tsunogai et al.'s (1999) original work focused on the East China Sea, and the observation that, averaged over the year, its surface waters represented a sink for carbon dioxide. This observation was combined with others of the distribution of dissolved carbonate and alkalinity and explained as follows : the shallowness of the continental shelf restricts convection of cooling water as a consequence, cooling is greater for continental shelf waters than for neighbouring open ocean waters this leads to the production of relatively cool and dense water on the shelf the cooler waters promote the solubility pump and lead to an increased storage of dissolved inorganic carbon this extra carbon storage is


id: coral-reef-20260505-0
file: data/en.wikipedia.org/wiki/Coral_reef-0.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Coral belongs to the class Anthozoa in the animal phylum Cnidaria, which includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons that support and protect the coral. Most reefs grow best in warm, shallow, clear, sunny, and agitated water. Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician, displacing the microbial and sponge reefs of the Cambrian. Sometimes called rainforests of the sea, shallow coral reefs form some of Earth's most diverse ecosystems. They occupy less than 0.1% of the world's ocean area, about half the area of France. Yet, they provide a home for at least 25% of all marine species, including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians. Coral reefs flourish in ocean waters that provide few nutrients. They are most commonly found at shallow depths in tropical waters, but deep water and cold water coral reefs exist on smaller scales in other areas. Shallow tropical coral reefs


id: coral-reef-20260505-1
file: data/en.wikipedia.org/wiki/Coral_reef-1.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
=== Material === As the name implies, coral reefs are made up of coral skeletons from mostly intact coral colonies. As other chemical elements present in corals become incorporated into the calcium carbonate deposits, aragonite is formed. However, shell fragments and the remains of coralline algae such as the green-segmented genus Halimeda can add to the reef's ability to withstand damage from storms and other threats. Such mixtures are visible in structures such as Eniwetok Atoll. === In the geologic past === The times of maximum reef development were in the Middle Cambrian (513–501 Ma), Devonian (416–359 Ma) and Carboniferous (359–299 Ma), owing to extinct order Rugosa corals, and Late Cretaceous (100–66 Ma) and Neogene (23 Ma–present), owing to order Scleractinia corals. Not all reefs in the past were formed by corals: those in the Early Cambrian (542–513 Ma) resulted from calcareous algae and archaeocyathids (small animals with conical shape, probably related to sponges) and in the Late Cretaceous (100–66 Ma), when reefs formed by a group of bivalves called rudists existed; one of the valves formed the main conical structure and the other, much smaller valve acted as a cap. Measurements of the oxygen isotopic composition of the aragonitic


id: coral-reef-20260505-2
file: data/en.wikipedia.org/wiki/Coral_reef-2.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
Atolls or atoll reefs are a more or less circular or continuous barrier reef that extends all the way around a lagoon without a central island. They are usually formed from fringing reefs around volcanic islands. Over time, the island erodes away and sinks below sea level. Atolls may also be formed by the sinking of the seabed or rising of the sea level. A ring of reefs results, which encloses a lagoon. Atolls are numerous in the South Pacific, where they usually occur in mid-ocean, for example, in the Caroline Islands, the Cook Islands, French Polynesia, the Marshall Islands, and Micronesia. Atolls are found in the Indian Ocean, for example, in the Maldives, the Chagos Islands, the Seychelles, and around Cocos Island. The entire Maldives consists of 26 atolls. === Other reef types or variants === Apron reef – short reef resembling a fringing reef, but more sloped; extending out and downward from a point or peninsular shore. The initial stage of a fringing reef. Bank reef – isolated, flat-topped reef larger than a patch reef and usually on mid-shelf regions and linear or semi-circular in shape; a type of platform reef. Patch reef – common, isolated, comparatively small


id: coral-reef-20260505-3
file: data/en.wikipedia.org/wiki/Coral_reef-3.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
The reef surface is the shallowest part of the reef. It is subject to surge and tides. When waves pass over shallow areas, they shoal, as shown in the adjacent diagram. This means the water is often agitated. These are the precise conditions under which corals flourish. The light is sufficient for photosynthesis by the symbiotic zooxanthellae, and agitated water brings plankton to feed the coral. The off-reef floor is the shallow sea floor surrounding a reef. This zone occurs next to reefs on continental shelves. Reefs around tropical islands and atolls drop abruptly to great depths and do not have such a floor. Usually sandy, the floor often supports seagrass meadows, which are important foraging areas for reef fish. The reef drop-off is, for its first 50 m, habitat for reef fish who find shelter on the cliff face and plankton in the water nearby. The drop-off zone primarily occurs around oceanic islands and atolls. The reef face is the zone above the reef floor or the reef drop-off. This zone is often the reef's most diverse area. Coral and calcareous algae provide complex habitats and areas that offer protection, such as cracks and crevices. Invertebrates and epiphytic algae


id: coral-reef-20260505-4
file: data/en.wikipedia.org/wiki/Coral_reef-4.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
The Great Barrier Reef—largest, comprising over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometers (1,600 mi) off Queensland, Australia The Mesoamerican Barrier Reef System—second largest, stretching 1,000 kilometers (620 mi) from Isla Contoy at the tip of the Yucatán Peninsula down to the Bay Islands of Honduras The New Caledonia Barrier Reef—second longest double barrier reef, covering 1,500 kilometers (930 mi) The Andros, Bahamas Barrier Reef—third largest, following the east coast of Andros Island, Bahamas, between Andros and Nassau The Red Sea—includes 6,000-year-old fringing reefs located along a 2,000 km (1,240 mi) coastline The Florida Reef Tract—largest continental US reef and the third-largest coral barrier reef, extends from Soldier Key, located in Biscayne Bay, to the Dry Tortugas in the Gulf of Mexico Blake Plateau has the world's largest known deep-water coral reef, comprising a 6.4 million-acre reef that stretches from Miami to Charleston, S. C. Its discovery was announced in January 2024. Pulley Ridge—deepest photosynthetic coral reef, Florida Numerous reefs around the Maldives The Philippines coral reef area, the second-largest in Southeast Asia, is estimated at 26,000 square kilometres. They are populated by over 900 reef fish species and 400 scleractinian coral species, 12 of which


id: coral-reef-20260505-5
file: data/en.wikipedia.org/wiki/Coral_reef-5.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
Corals reproduce both sexually and asexually. An individual polyp uses both reproductive modes within its lifetime. Corals reproduce sexually by either internal or external fertilization. The reproductive cells are found on the mesenteries, membranes that radiate inward from the layer of tissue that lines the stomach cavity. Some mature adult corals are hermaphroditic; others are exclusively male or female. A few species change sex as they grow. Internally fertilized eggs develop in the polyp for a period ranging from days to weeks. Subsequent development produces a tiny larva, known as a planula. Externally fertilized eggs develop during synchronized spawning. Polyps across a reef simultaneously release eggs and sperm into the water en masse. Spawn disperse over a large area. The timing of spawning depends on the time of year, water temperature, and tidal and lunar cycles. Spawning is most successful when there is little variation between high and low tide. The less water movement, the better the chance for fertilization. The release of eggs or planula usually occurs at night and is sometimes in phase with the lunar cycle (three to six days after a full moon). The period from release to settlement lasts only a few days, but some


id: coral-reef-20260505-6
file: data/en.wikipedia.org/wiki/Coral_reef-6.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
In The Structure and Distribution of Coral Reefs, published in 1842, Darwin described how coral reefs were found in some tropical areas but not others, with no obvious cause. The largest and strongest corals grew in parts of the reef exposed to the most violent surf, and corals were weakened or absent where loose sediment accumulated. Tropical waters contain few nutrients yet a coral reef can flourish like an "oasis in the desert". This has given rise to the ecosystem conundrum, sometimes called "Darwin's paradox": "How can such high production flourish in such nutrient poor conditions?" Coral reefs support over one-quarter of all marine species. This diversity results in complex food webs, with large predator fish eating smaller forage fish, which eat yet smaller zooplankton, and so on. However, all food webs ultimately depend on plants, which serve as primary producers. Coral reefs typically produce 5–10 grams of carbon per square meter per day (gC·m−2·day−1) biomass. One reason for the unusual clarity of tropical waters is their nutrient deficiency and drifting plankton. Further, the sun shines year-round in the tropics, warming the surface layer, making it less dense than subsurface layers. The warmer water is separated from deeper, cooler water


id: coral-reef-20260505-7
file: data/en.wikipedia.org/wiki/Coral_reef-7.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
== Biodiversity == Coral reefs form some of the world's most productive ecosystems, providing complex and varied marine habitats that support a wide range of organisms. Fringing reefs just below low tide level have a mutually beneficial relationship with mangrove forests at high tide level and sea grass meadows in between: the reefs protect the mangroves and seagrass from strong currents and waves that would damage them or erode the sediments in which they are rooted, while the mangroves and sea grass protect the coral from large influxes of silt, fresh water and pollutants. This level of environmental variety benefits many coral reef animals, which, for example, may feed on seagrass and use the reefs for protection or breeding. Reefs are home to a variety of animals, including fish, seabirds, sponges, cnidarians (which includes some types of corals and jellyfish), worms, crustaceans (including shrimp, cleaner shrimp, spiny lobsters and crabs), mollusks (including cephalopods), echinoderms (including starfish, sea urchins and sea cucumbers), sea squirts, sea turtles and sea snakes. Aside from humans, mammals are rare on coral reefs, with visiting cetaceans such as dolphins being the main exception. A few species feed directly on corals, while others graze on algae on


id: coral-reef-20260505-8
file: data/en.wikipedia.org/wiki/Coral_reef-8.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
== Ecosystem services == Coral reefs deliver ecosystem services to tourism, fisheries, and coastline protection. The global economic value of coral reefs has been estimated to be between US$29.8 billion and $375 billion per year. About 500 million people benefit from ecosystem services provided by coral reefs. The economic cost of destroying one square kilometre of coral reef over 25 years has been estimated at between $137,000 and $1,200,000. To improve the management of coastal coral reefs, the World Resources Institute (WRI) developed and published tools to calculate the value of coral reef-related tourism, shoreline protection, and fisheries, partnering with five Caribbean countries. As of April 2011, published working papers covered St. Lucia, Tobago, Belize, and the Dominican Republic. The WRI was "making sure that the study results support improved coastal policies and management planning". The Belize study estimated the value of reef and mangrove services at $395–559 million annually. Bermuda's coral reefs provide economic benefits to the Island worth, on average, $722 million per year, based on six key ecosystem services, according to Sarkis et al. (2010). === Shoreline protection === Coral reefs protect shorelines by absorbing wave energy, and many small islands would not exist without reefs. Coral


id: coral-reef-20260505-9
file: data/en.wikipedia.org/wiki/Coral_reef-9.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
Marine protected areas (MPAs) are areas designated because they provide various kinds of protection to ocean and/or estuarine areas. They are intended to promote responsible fishery management and habitat protection. MPAs can also encompass social and biological objectives, including reef restoration, aesthetics, biodiversity, and economic benefits. The effectiveness of MPAs is still debated. For example, a study investigating the success of a small number of MPAs in Indonesia, the Philippines, and Papua New Guinea found no significant differences between the MPAs and unprotected sites. Furthermore, in some cases they can generate local conflict, due to a lack of community participation, clashing views of the government and fisheries, effectiveness of the area and funding. In some situations, as in the Phoenix Islands Protected Area, MPAs provide revenue to locals. The level of income provided is similar to the income they would have generated without controls. Overall, it appears the MPAs can protect local coral reefs, but that clear management and sufficient funds are required. The Caribbean Coral Reefs – Status Report 1970–2012 states that coral decline may be reduced or even reversed. For this, overfishing needs to be stopped, especially fishing on species key to coral reefs, such as parrotfish. Direct


id: coral-reef-20260505-10
file: data/en.wikipedia.org/wiki/Coral_reef-10.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
Coral gardens take advantage of a coral's natural ability to fragment and continue to grow if the fragments can anchor themselves onto new substrates. This method was first tested by Baruch Rinkevich in 1995 which found success at the time. By today's standards, coral farming has evolved into various forms, but it still aims to cultivate corals. Consequently, coral farming quickly replaced previously used transplantation methods, which involved physically moving sections or entire coral colonies to a new area. Transplantation has seen success in the past, and decades of experiments have led to a high success and survival rate. However, this method still requires removing corals from existing reefs. Given the current state of reefs, this method should generally be avoided if possible. Saving healthy corals from eroding substrates or reefs doomed to collapse could be a significant advantage of using transplantation. Coral gardens generally take on safe forms, no matter where you go. It begins with the establishment of a nursery where operators can observe and care for coral fragments. It goes without saying that nurseries should be established in areas that are going to maximize growth and minimize mortality. Floating offshore coral trees or even aquariums are possible


id: coral-reef-20260505-11
file: data/en.wikipedia.org/wiki/Coral_reef-11.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
=== Heat-tolerant symbionts === Another possibility for coral restoration is gene therapy: inoculating coral with genetically modified bacteria, or naturally occurring heat-tolerant varieties of coral symbiotes, may make it possible to grow corals that are more resistant to climate change and other threats. Warming oceans are forcing corals to adapt to unprecedented temperatures. Those that do not have a tolerance for the elevated temperatures experience coral bleaching and eventually mortality. There is already research aimed at creating genetically modified corals that can withstand a warming ocean. Madeleine J. H. van Oppen, James K. Oliver, Hollie M. Putnam, and Ruth D. Gates described four levels of human intervention for genetically modifying corals, each increasing in intensity. These methods focus on altering the genetics of the zooxanthellae within coral rather than the alternative. The first method is to induce acclimatization of the first generation of corals. The idea is that when adult and offspring corals are exposed to stressors, the zooxanthellae will gain a mutation. This method is based primarily on the chance that the zooxanthellae will acquire the specific trait that will enable them to better survive in warmer waters. The second method focuses on identifying the different kinds of zooxanthellae


id: coral-reef-20260505-12
file: data/en.wikipedia.org/wiki/Coral_reef-12.md
category: reference
title: Coral reef
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coral_reef
date_saved: 2026-05-05T07:34:41.179437+00:00
instance: kb-cron
parent: coral-reef-20260505-0
summary:
Deep-water coral — Corals living in the cold waters of deeper, darker parts of the oceans Mesophotic coral reef — Corals living in the mesopelagic or twilight zone Fossil Coral Reef – National Natural Landmark in Le Roy, New York Census of Coral Reefs – Field project of the Census of Marine Life Catlin Seaview Survey Coral reef organizations Sponge reef – Reefs produced by sea sponges Pseudo-atoll – Island that encircles a lagoon == References == == Further references == Coral Reef Protection: What Are Coral Reefs?. US EPA. UNEP. 2004. Coral Reefs in the South China Sea. UNEP/GEF/SCS Technical Publication No. 2. UNEP. 2007. Coral Reefs Demonstration Sites in the South China Sea. UNEP/GEF/SCS Technical Publication No. 5. UNEP, 2007. National Reports on Coral Reefs in the Coastal Waters of the South China Sea. UNEP/GEF/SCS Technical Publication No. 11. == External links == "Coral Reef Factsheet". Waitt Institute. Archived from the original on 9 June 2015. Retrieved 8 June 2015. Corals and Coral Reefs overview at the Smithsonian Ocean Portal About Corals Archived 26 December 2013 at the Wayback Machine Australian Institute of Marine Science. International Coral Reef Initiative Moorea Coral Reef Long Term Ecological Research Site (US


id: cyclic-steps-20260505-0
file: data/en.wikipedia.org/wiki/Cyclic_steps-0.md
category: reference
title: Cyclic steps
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cyclic_steps
date_saved: 2026-05-05T07:34:42.484931+00:00
instance: kb-cron
parent: cyclic-steps-20260505-0
summary:
Cyclic steps are rhythmic bedforms associated with Froude super-critical flow instability. They are a type of sediment wave, and are created when supercritical sediment-laden water (turbidity currents) travels downslope through sediment beds. Each "step" has a steep drop, and together they tend to migrate upstream. On the ocean floor, this phenomenon was first shown to be possible in 2006, although it was observed in open-channel flows over a decade earlier. Geological features appearing to be submarine cyclic steps have been detected in the northern lowlands of Mars in the Aeolis Mensae region, providing evidence of an ancient Martian ocean. == Formation == There are many parameters which govern the formation of cyclic steps: bed slope, bed porosity, erosion resistance, sediment concentration, and flow rate all play a role. Tilting flumes can be used to create cyclic steps in subaerial laboratory conditions, provided the Froude number is high enough. If the Froude number is lower than required, then antidunes will form instead. Additionally, if the sediment is too fine, then chute-and-pool features will form. In subaqueous conditions, most of the work has traditionally been in building mathematical, rather than physical, models of cyclic step formation. However, cyclic steps have attracted increasing


id: dark-oxygen-20260505-0
file: data/en.wikipedia.org/wiki/Dark_oxygen-0.md
category: reference
title: Dark oxygen
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark_oxygen
date_saved: 2026-05-05T07:34:43.702448+00:00
instance: kb-cron
parent: dark-oxygen-20260505-0
summary:
Dark oxygen production refers to the generation of molecular oxygen (O2) through processes that do not involve light-dependent oxygenic photosynthesis. The name therefore uses a different sense of 'dark' than that used in the phrase "biological dark matter" (for example) which indicates obscurity to scientific assessment rather than the photometric meaning. While the majority of Earth's oxygen is produced by plants and photosynthetically active microorganisms via photosynthesis, dark oxygen production occurs via a variety of abiotic and biotic processes and may support aerobic metabolism in dark, anoxic environments. The theory for dark oxygen production by manganese nodules on the abyssal seafloor is controversial, with scientists disagreeing about its validity. == Abiotic production == Abiotic production of dark oxygen can occur through several mechanisms, such as: Water radiolysis: This process typically takes place in dark geological ecosystems, such as aquifers, where the decay of radioactive elements in surrounding rock leads to the breakdown of water molecules, producing O2. Oxidation of surface-bound radicals: On silicon-bearing minerals like quartz, surface-bound radicals can undergo oxidation, contributing to O2 production. In addition to direct O2 formation, these processes often produce reactive oxygen species (ROS), such as hydroxyl radicals (OH•), superoxide (O2•-), and hydrogen peroxide (H2O2).


id: dead-zone-ecology-20260505-0
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-0.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes. Hypoxia occurs when dissolved oxygen (DO) concentration falls to or below 2 mg of O2/liter. When a body of water experiences hypoxic conditions, aquatic flora and fauna begin to change behavior in order to reach sections of water with higher oxygen levels. Once DO declines below 0.5 mg O2/liter in a body of water, mass mortality occurs. With such a low concentration of DO, these bodies of water fail to support the aquatic life living there. Historically, many of these sites were naturally occurring. However, in the 1970s, oceanographers began noting increased instances and expanses of dead zones. These occur near inhabited coastlines, where aquatic life is most concentrated. Coastal regions, such as the Baltic Sea, the northern Gulf of Mexico, and the Chesapeake Bay, as well as large enclosed water bodies like Lake Erie, have been affected by deoxygenation due to eutrophication. Excess nutrients are put into these systems by rivers, ultimately from urban and agricultural runoff and exacerbated by deforestation. These nutrients lead to high productivity that produces organic material that sinks to the bottom and is respired. The respiration of that organic material uses


id: dead-zone-ecology-20260505-1
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-1.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
Limnologist David Schindler, whose research at the Experimental Lakes Area led to the banning of harmful phosphates in detergents, warned about algal blooms and dead zones, "The fish-killing blooms that devastated the Great Lakes in the 1960s and 1970s haven't gone away; they've moved west into an arid world in which people, industry, and agriculture are increasingly taxing the quality of what little freshwater there is to be had here....This isn't just a prairie problem. Global expansion of dead zones caused by algal blooms is rising rapidly." The major groups of algae are cyanobacteria, green algae, dinoflagellates, coccolithophores and diatom algae. An increase in the input of nitrogen and phosphorus generally causes cyanobacteria to bloom. Other algae are consumed and thus do not accumulate to the same extent as cyanobacteria. Cyanobacteria are not good food for zooplankton and fish and hence accumulate in water, die, and then decompose. The bacterial degradation of their biomass consumes the oxygen in the water, thereby creating the state of hypoxia. Dead zones can be caused by natural and by anthropogenic factors. Natural causes include coastal upwelling, changes in wind, and water circulation patterns. Other environmental factors that determine the occurrence or intensity of a


id: dead-zone-ecology-20260505-2
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-2.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
The most notable effects of eutrophication are vegetal blooms, sometimes toxic, loss of biodiversity and anoxia, which can lead to the massive death of aquatic organisms. Due to the hypoxic conditions present in dead zones, marine life within these areas tends to be scarce. Most fish and motile organisms tend to emigrate out of the zone as oxygen concentrations fall, and benthic populations may experience severe losses when oxygen concentrations are below 0.5 mg l−1 O2. In severe anoxic conditions, microbial life may experience dramatic shifts in community identity as well, resulting in an increased abundance of anaerobic organisms as aerobic microbes decrease in number and switch energy sources for oxidation such as nitrate, sulfate, or iron reduction. Sulfur reduction is a particular concern as hydrogen sulfide is toxic and stresses most organisms within the zone further, exacerbating mortality risks. Low oxygen levels can have severe effects on survivability of organisms inside the area while above lethal anoxic conditions. Studies conducted along the Gulf Coast of North America have shown hypoxic conditions lead to reduction of reproductive rates and growth rates in a variety of organisms including fish and benthic invertebrates. Organisms able to leave the area typically do so


id: dead-zone-ecology-20260505-3
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-3.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
=== Jellyfish blooms === Despite most other life forms being killed by the lack of oxygen, jellyfish can thrive and are sometimes present in dead zones in vast numbers. Jellyfish blooms produce large quantities of mucus, leading to major changes in food webs in the ocean since few organisms feed on them. The organic carbon in mucus is metabolized by bacteria which return it to the atmosphere in the form of carbon dioxide in what has been termed a "jelly carbon shunt". The potential worsening of jellyfish blooms as a result of human activities has driven new research into the influence of dead zones on jelly populations. The primary concern is the potential for dead zones to serve as breeding grounds for jelly populations as a result of the hypoxic conditions driving away competition for resources and common predators of jellyfish. The increased population of jellyfish could have high commercial costs with loss of fisheries, destruction and contamination of trawling nets and fishing vessels, and lowered tourism revenue in coastal systems. === Seagrass beds === Globally, seagrass has been declining rapidly. It is estimated that 21% of the 71 known seagrass species have decreasing population trends and 11% of those


id: dead-zone-ecology-20260505-4
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-4.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
Researchers from Baltic Nest Institute published in one of PNAS issues reports that the dead zones in the Baltic Sea have grown from approximately 5,000 km2 to more than 60,000 km2 in recent years. Some of the causes behind the elevated increase of dead zones can be attributed to the use of fertilizers, large animal farms, the burning of fossil fuels, and effluents from municipal wastewater treatment plants. With its massive size, the Baltic Sea is best analyzed in sub-areas rather than as a whole. In a paper published in 2004, researchers specifically divided the Baltic Sea into 9 sub-areas, each having its own specific characteristics. The 9 sub-areas are discerned as follows: Gulf of Bothnia, Archipelago region, Gulf of Finland, Gulf of Riga, Gulf of Gdansk, Swedish East-coast, Central Baltic, Belt Sea region, and Kattegat. Each sub-area has responded differently to nutrient additions and eutrophication; however, there are a few general patterns and measures for the Baltic Sea as a whole. As the researchers Rönnberg and Bonsdorff state, "Irrespective of the area-specific effects of the increased loads of nutrients to the Baltic Sea, the sources are more or less similar in the whole region. The extent and the severity


id: dead-zone-ecology-20260505-5
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-5.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
=== Lower St. Lawrence Estuary === A dead zone exists in the Lower St. Lawrence River area from east the Saguenay River to east of Baie Comeau, greatest at depths over 275 metres (902 ft) and noticed since the 1930s. The main concern for Canadian scientists is the impact on fish found in the area. === Oregon === There is a hypoxic zone covering the coasts of Oregon and Washington that reached peak size in 2006 at an area of over 1,158 square miles. Strong surface winds between April and September cause frequent upwelling that results in an increase of algae blooms, rendering the hypoxia a seasonal occurrence. The upwelling has contributed to lower temperatures within the zone. The dead zone has resulted in sea organisms such as crabs and fish relocating and an interference with commercial fishing. Organisms that cannot relocate have been found to suffocate, leaving them useless for fishermen. In 2009, one scientist described "thousands and thousands" of suffocated, crabs, worms, and sea stars along the seafloor of the hypoxic zone. In 2021, 1.9 million dollars were put into monitoring and continuing to study the hypoxic conditions in the area that the dead zone occurs in. ===


id: dead-zone-ecology-20260505-6
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-6.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
==== Economic impact ==== Some assert that the dead zone threatens lucrative commercial and recreational fisheries in the Gulf of Mexico. "In 2009, the dockside value of commercial fisheries in the Gulf was $629 million. Nearly three million recreational fishers further contributed about $10 billion to the Gulf economy, taking 22 million fishing trips." The seafood production is not only hurting states located on the Gulf of Mexico but the U.S. as a whole. It is reported that the Gulf of Mexico dead zone is costing the U.S. seafood and tourism industries about $82 million a year. Louisiana is ranked second in seafood production behind Alaska, and this impact can be devastating for the nations seafood production since the Gulf of Mexico sources 40% of the nations seafood. Scientists are not in universal agreement that nutrient loading has a negative impact on fisheries. Grimes makes a case that nutrient loading enhances the fisheries in the Gulf of Mexico. Courtney et al. hypothesize that nutrient loading may have contributed to the increases in red snapper in the northern and western Gulf of Mexico. In 2017, Tulane University offered a $1 million challenge grant for growing crops with less fertilizer. ==== History


id: dead-zone-ecology-20260505-7
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-7.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
== Prediction and Use of AI for Dead Zones == Dead zones are hard to predict since they use multiple environmental factors. They use nutrient runoff, rainfall, water temperature, and dissolved oxygen levels. Due to this, traditional modeling uses field sampling and satellite observations in order to see major changes. Though this does not measure rapid change, it won't be able to see complete coverage of major areas. Due to this issue, there has been research using artificial intelligence (AI) and machine learning models to increase prediction accuracy and areas that are at risk. This can help see what areas risk of hypoxia before it develops. AI can examine large environmental databases to recognize patters associated with dead zone formations. Machine learning algorithms process information like nitrogen and phosphorus concentrations, precipitation rates, and more, to estimate where low oxygen conditions occur and when. These systems come in handy when monitoring data are incomplete or unavailable allowing researchers to estimate missing data and improve prediction rates. Researchers at Louisiana state University have developed AI-based tools to predict nutrient pollution in watersheds connected to Gulf of Mexico. These tools use machine learning to estimate nutrient runoff from rivers and agriculture land. This


id: dead-zone-ecology-20260505-8
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-8.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
== Biotechnology Application == There are some options that can aid in the reversal process of a dead zone and eventual recovery of water quality and benthic communities through applied biotechnology methodology if a given management project can apply it if the conditions of a dead-zone fit within the criteria. One of the more natural options is established filter feeding species within a marine community that are nearby a impacted ecological area transitioned into a dead zone that can then spread and possibly establish a population there in which recovery time can vary as they filter out access nitrogen and phosphorus. Given that many filter feeding species have different tolerance levels due to the extreme hypoxic conditions, it can be determined through research of how various species respond behaviorally to those specific conditions and deduce the most appropriate species based on a dead-zone of interest to recover. An 8-day study was done on eastern oysters (Crassostrea virginica) and soft-shell clams (Mya arenaria) to assess their reactions to hypoxic and heatwave conditions. While this study was meant for establishing an understanding of behavioral patterns in warming conditions for filter-feeding species, this type of approach can be conducted on other filter-feeding species


id: dead-zone-ecology-20260505-9
file: data/en.wikipedia.org/wiki/Dead_zone_(ecology)-9.md
category: reference
title: Dead zone (ecology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dead_zone_(ecology)
date_saved: 2026-05-05T07:34:44.955451+00:00
instance: kb-cron
parent: dead-zone-ecology-20260505-0
summary:
== Further reading == Growing 'dead zone' Confirmed by Underwater Robots in the Gulf of Oman, phys.org, April 2018 Hendy, Ian (August 2017), Gulf of Mexico 'dead zone' is already a disaster – but it could get worse, The Conversation Bryant, Lee (April 2015), Ocean 'dead zones' are spreading – and that spells disaster for fish, The Conversation Deprecated link at archive.today (archived January 29, 2013) Suzie Greenhalgh and Amanda Sauer (WRI), "Awakening the 'Dead Zone': An investment for agriculture, water quality, and climate change" 2003 Reyes Tirado (July 2008) Dead Zones: How Agricultural Fertilizers are Killing our Rivers, Lakes and Oceans. Greenpeace publications. See also: "Dead Zones: How Agricultural Fertilizers are Killing our Rivers, Lakes and Oceans". Greenpeace Canada. July 7, 2008. Archived from the original on September 8, 2010. Retrieved August 3, 2010. MSNBC report on dead zones, March 29, 2004 Joel Achenbach, "A 'Dead Zone' in The Gulf of Mexico: Scientists Say Area That Cannot Support Some Marine Life Is Near Record Size", The Washington Post, July 31, 2008 Joel Achenbach, "'Dead Zones' Appear In Waters Worldwide: New Study Estimates More Than 400", The Washington Post, August 15, 2008 == External links == Louisiana Universities Marine Consortium


id: deep-sea-20260505-0
file: data/en.wikipedia.org/wiki/Deep_sea-0.md
category: reference
title: Deep sea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep_sea
date_saved: 2026-05-05T07:34:46.246452+00:00
instance: kb-cron
parent: deep-sea-20260505-0
summary:
The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of 200 m (660 ft) or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combination of low temperatures, darkness, and high pressure. The deep sea is considered the least explored Earth biome as the extreme conditions make the environment difficult to access and explore. Organisms living within the deep sea have a variety of adaptations to survive in these conditions. Organisms can survive in the deep sea through a number of feeding methods including scavenging, predation and filtration, with a number of organisms surviving by feeding on marine snow. Marine snow is organic material that has fallen from upper waters into the deep sea. In 1960, the bathyscaphe Trieste descended to the bottom of the Mariana Trench near Guam, at 10,911 m (35,797 ft; 6.780 mi), the deepest known spot in any ocean. If Mount Everest (8,848 m or 29,029 ft or 5.498 mi) were submerged there, its peak would be more than 2 km (1.2 mi) beneath the surface. After the Trieste was retired, the Japanese remote-operated vehicle (ROV) Kaikō was


id: deep-sea-20260505-1
file: data/en.wikipedia.org/wiki/Deep_sea-1.md
category: reference
title: Deep sea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep_sea
date_saved: 2026-05-05T07:34:46.246452+00:00
instance: kb-cron
parent: deep-sea-20260505-0
summary:
Regions below the epipelagic are divided into further zones, beginning with the bathyal zone (also considered the continental slope) which spans from 200 to 3,000 meters (660 to 9,840 ft) below sea level and is essentially transitional, containing elements from both the shelf above and the abyss below. Below this zone, the deep sea consists of the abyssal zone (ocean depth between 3–6 km; 1.9–3.7 mi) and the hadal zone (6–11 km; 3.7–6.8 mi). Food consists of falling organic matter known as 'marine snow' and carcasses derived from the productive zone above, and is scarce both in terms of spatial and temporal distribution. Instead of relying on gas for their buoyancy, many deep-sea species have jelly-like flesh consisting mostly of glycosaminoglycans, which provides them with very low density. It is also common among deep water squid to combine the gelatinous tissue with a flotation chamber filled with a coelomic fluid made up of the metabolic waste product ammonium chloride, which is lighter than the surrounding water. The midwater fish have special adaptations to cope with these conditions—they are small, usually being under 25 centimetres (10 in); they have slow metabolisms and unspecialized diets, preferring to sit and wait for food


id: deep-sea-20260505-2
file: data/en.wikipedia.org/wiki/Deep_sea-2.md
category: reference
title: Deep sea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep_sea
date_saved: 2026-05-05T07:34:46.246452+00:00
instance: kb-cron
parent: deep-sea-20260505-0
summary:
=== Adaptation to hydrostatic pressure === Deep-sea fish have different adaptations in their proteins, anatomical structures, and metabolic systems to survive in the Deep sea, where the inhabitants have to withstand great amount of hydrostatic pressure. While other factors like food availability and predator avoidance are important, the deep-sea organisms must have the ability to maintain well-regulated metabolic system in the face of high pressures. In order to adjust for the extreme environment, these organisms have developed unique characteristics. Proteins are affected greatly by the elevated hydrostatic pressure, as they undergo changes in water organization during hydration and dehydration reactions of the binding events. This is due to the fact that most enzyme-ligand interactions form through charged or polar non-charge interactions. Because hydrostatic pressure affects both protein folding and assembly and enzymatic activity, the deep sea species must undergo physiological and structural adaptations to preserve protein functionality against pressure. Actin is a protein that is essential for different cellular functions. The α-actin serves as a main component for muscle fiber, and it is highly conserved across numerous different species. Some Deep-sea fish developed pressure tolerance through the change in mechanism of their α-actin. In some species that live in depths


id: deep-sea-fish-20260505-0
file: data/en.wikipedia.org/wiki/Deep-sea_fish-0.md
category: reference
title: Deep-sea fish
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep-sea_fish
date_saved: 2026-05-05T07:34:47.616452+00:00
instance: kb-cron
parent: deep-sea-fish-20260505-0
summary:
Deep-sea fish are fish that live in the darkness below the sunlit surface waters, that is below the epipelagic or photic zone of the sea. The lanternfish is, by far, the most common deep-sea fish. Other deep-sea fishes include the flashlight fish, cookiecutter shark, bristlemouths, anglerfish, viperfish, and some species of eelpout. Only about 2% of known marine species inhabit the pelagic environment. This means that they live in the water column as opposed to the benthic organisms that live in or on the sea floor. Deep-sea organisms generally inhabit bathypelagic (1–4 km; 0.62–2.49 mi deep) and abyssopelagic (4–6 km; 2.5–3.7 mi deep) zones. However, characteristics of deep-sea organisms, such as bioluminescence can be seen in the mesopelagic (200–1,000 m; 660–3,280 ft deep) zone as well. The mesopelagic zone is the disphotic zone, meaning light there is minimal but still measurable. The oxygen minimum layer exists somewhere between a depth of 700 and 1,000 metres (2,300 and 3,300 ft) depending on the place in the ocean. This area is also where nutrients are most abundant. The bathypelagic and abyssopelagic zones are aphotic, meaning that no light penetrates this area of the ocean. These zones make up about 75% of the


id: deep-sea-fish-20260505-1
file: data/en.wikipedia.org/wiki/Deep-sea_fish-1.md
category: reference
title: Deep-sea fish
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep-sea_fish
date_saved: 2026-05-05T07:34:47.616452+00:00
instance: kb-cron
parent: deep-sea-fish-20260505-0
summary:
In the deep ocean, the waters extend far below the epipelagic zone, and support very different types of pelagic fishes adapted to living in these deeper zones. In deep water, marine snow is a continuous shower of mostly organic detritus falling from the upper layers of the water column. Its origin lies in activities within the productive photic zone. Marine snow includes dead or dying plankton, protists (diatoms), fecal matter, sand, soot and other inorganic dust. The "snowflakes" grow over time and may reach several centimetres in diameter, travelling for weeks before reaching the ocean floor. However, most organic components of marine snow are consumed by microbes, zooplankton and other filter-feeding animals within the first 1,000 metres (3,300 ft) of their journey, that is, within the epipelagic zone. In this way, marine snow may be considered the foundation of deep-sea mesopelagic and benthic ecosystems: as sunlight cannot reach them, deep-sea organisms rely heavily on marine snow as an energy source. Since there is no light in the deep sea (aphotic), there is a lack of primary producers. Therefore, most organisms in the bathypelagic rely on the marine snow from regions higher in the vertical column. Some deep-sea pelagic groups, such


id: deep-sea-fish-20260505-2
file: data/en.wikipedia.org/wiki/Deep-sea_fish-2.md
category: reference
title: Deep-sea fish
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep-sea_fish
date_saved: 2026-05-05T07:34:47.616452+00:00
instance: kb-cron
parent: deep-sea-fish-20260505-0
summary:
The fish of the deep-sea have evolved various adaptations to survive in this region. Since many of these fish live in regions where there is no natural illumination, they cannot rely solely on their eyesight for locating prey and mates and avoiding predators; deep-sea fish have evolved appropriately to the extreme sub-photic region in which they live. Many of these organisms are blind and rely on their other senses, such as sensitivities to changes in local pressure and smell, to catch their food and avoid being caught. Those that aren't blind have large and sensitive eyes that can use bioluminescent light. These eyes can be as much as 100 times more sensitive to light than human eyes. Rhodopsin (Rh1) is a protein found in the eye's rod cells that helps animals see in dim light. While most vertebrates usually have one Rh1 opsin gene, some deep-sea fish have several Rh1 genes, and one species, the silver spinyfin (Diretmus argenteus), has 38. This proliferation of Rh1 genes may help deep-sea fish to see in the depths of the ocean. Also, to avoid predation, many species are dark to blend in with their environment. Many deep-sea fish are bioluminescent, with extremely large


id: deep-sea-fish-20260505-3
file: data/en.wikipedia.org/wiki/Deep-sea_fish-3.md
category: reference
title: Deep-sea fish
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep-sea_fish
date_saved: 2026-05-05T07:34:47.616452+00:00
instance: kb-cron
parent: deep-sea-fish-20260505-0
summary:
Below the epipelagic zone, conditions change rapidly. Between 200 m and about 1000 m, light continues to fade until there is almost none. Temperatures fall through a thermocline to temperatures between 3.9 and 7.8 °C (39.0 and 46.0 °F). This is the twilight or mesopelagic zone. Pressure continues to increase, at the rate of one atm (0.1 MPa) every 10 m (33 ft), while nutrient concentrations fall, along with dissolved oxygen and the rate at which the water circulates. Sonar operators, using the newly developed sonar technology during World War II, were puzzled by what appeared to be a false sea floor 300–500 metres (984–1,640 ft) deep by day, and less deep at night. This turned out to be due to millions of marine organisms, most particularly small mesopelagic fish, with swim bladders that reflected the sonar. These organisms migrate up into shallower water at dusk to feed on plankton. The layer is deeper when the moon is out, and can become shallower when clouds pass over the moon. This phenomenon has come to be known as the deep scattering layer. Most mesopelagic fish make daily vertical migrations, moving at night into the epipelagic zone, often following similar migrations of


id: deep-sea-fish-20260505-4
file: data/en.wikipedia.org/wiki/Deep-sea_fish-4.md
category: reference
title: Deep-sea fish
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep-sea_fish
date_saved: 2026-05-05T07:34:47.616452+00:00
instance: kb-cron
parent: deep-sea-fish-20260505-0
summary:
Below the mesopelagic zone it is pitch dark. This is the midnight (or bathypelagic zone), extending from 1,000 metres (3,281 ft) to the bottom deep-water benthic zone. If the water is exceptionally deep, the pelagic zone below 4,000 metres (13,123 ft) is sometimes called the lower midnight (or abyssopelagic zone). Temperatures in this zone range from 1 to 4 °C (34 to 39 °F) and it is completely aphotic. Conditions are somewhat uniform throughout these zones; the darkness is complete, the pressure is crushing, and temperatures, nutrients and dissolved oxygen levels are all low. Bathypelagic fish have special adaptations to cope with these conditions – they have slow metabolisms and unspecialized diets, being willing to eat anything that comes along. They prefer to sit and wait for food rather than waste energy searching for it. The behaviour of bathypelagic fish can be contrasted with the behaviour of mesopelagic fish. Mesopelagic fish are often highly mobile, whereas bathypelagic fish are almost all lie-in-wait predators, normally expending little energy in movement. The dominant bathypelagic fishes are small bristlemouth and anglerfish; fangtooth, viperfish, daggertooth and barracudina are also common. These fishes are small, many about 10 centimetres (3.9 in) long, and not many


id: deep-sea-fish-20260505-5
file: data/en.wikipedia.org/wiki/Deep-sea_fish-5.md
category: reference
title: Deep-sea fish
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep-sea_fish
date_saved: 2026-05-05T07:34:47.616452+00:00
instance: kb-cron
parent: deep-sea-fish-20260505-0
summary:
== Adaptation to high pressure == As a fish moves deeper into the sea, the weight of the water overhead exerts increasing hydrostatic pressure on the fish. This increased pressure amounts to about one atm (0.1 MPa) for every 10 m (33 ft)in depth. For a fish at the bottom of the bathypelagic zone, this pressure amounts to about 400 atm (40 MPa, 6000 psi). Deep-sea organisms possess adaptations at cellular and physiological levels that allow them to survive in environments of great pressure. Not having these adaptations limits the depths at which shallow-water species can operate. High levels of external pressure affects how metabolic processes and biochemical reactions proceed. The equilibrium of many chemical reactions is disturbed by pressure, and pressure can inhibit processes which result in an increase in volume. Water, a key component in many biological processes, is very susceptible to volume changes, mainly because constituents of cellular fluid have an effect on water structure. Thus, enzymatic reactions that induce changes in water organization effectively change the system's volume. Proteins responsible for catalyzing reactions are typically held together by weak bonds and the reactions usually involve volume increases. Species that can tolerate these depths have evolved changes


id: deep-ocean-water-20260505-0
file: data/en.wikipedia.org/wiki/Deep_ocean_water-0.md
category: reference
title: Deep ocean water
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep_ocean_water
date_saved: 2026-05-05T07:34:48.870613+00:00
instance: kb-cron
parent: deep-ocean-water-20260505-0
summary:
Deep ocean water (DOW) is the name for cold, salty water found in the deep sea, starting at 200 m (660 ft) below the surface of Earth's oceans. Ocean water differs in temperature and salinity. Warm surface water is generally saltier than the cooler deep or polar waters; in polar regions, the upper layers of ocean water are cold and fresh. Deep ocean water makes up about 90% of the volume of the oceans. Deep ocean water has a very uniform temperature, around 0–3 °C (32–37 °F), and a salinity of about 3.5% or, as oceanographers state, 35‰ (parts per thousand). In specialized locations, such as the Natural Energy Laboratory of Hawaii, ocean water is pumped to the surface from approximately 900 m (3,000 ft) deep for applications in research, commercial and pre-commercial activities. DOW is typically used to describe ocean water at sub-thermal depths sufficient to provide a measurable difference in water temperature. == Cold-bed agriculture == A potential indirect use of cold ocean water is "cold-bed agriculture". During condensation or ocean thermal energy conversion operations, the water does not reach ambient temperature, because a certain temperature gradient is required to make these processes viable. The water leaving those


id: deep-sea-wood-20260505-0
file: data/en.wikipedia.org/wiki/Deep-sea_wood-0.md
category: reference
title: Deep-sea wood
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Deep-sea_wood
date_saved: 2026-05-05T07:34:50.198701+00:00
instance: kb-cron
parent: deep-sea-wood-20260505-0
summary:
Deep-sea wood is the term for wood which sinks to the ocean floor. These wood-falls develop deep sea ecosystems. Deep-sea wood supports unique forms of deep sea community life including chemo-synthetic bacteria. Sources of carbon for these deep sea ecosystems are not limited to sunken wood, but also include kelp and the remains of whales. Much of what is known about deep-sea wood is obtained from experiments by marine biologists, in which wood is forced to the bottom of the ocean for a set amount of time and is then collected later for sampling. == Organisms present == === Wood boring bivalves === Colonization experiments revealed the presence of wood boring bivalves that belong to the subfamily Xylophagainae, such as Xylophaga dorsalis, or other species recently described from deep-sea canyons. They range in shell size from 1 to 10 mm (0.04 to 0.4 in). These bivalves are able to digest wood with the help of symbiotic bacteria in their gills. === Chemosyntheic fauna === Chemosyntheic mussels identified as Idas modiolaeformis were also found in deep sea wood when organic matter settled for at least one year. They are slightly smaller than the bivalves found and range in length from 1


id: demersal-zone-20260505-0
file: data/en.wikipedia.org/wiki/Demersal_zone-0.md
category: reference
title: Demersal zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Demersal_zone
date_saved: 2026-05-05T07:34:51.436336+00:00
instance: kb-cron
parent: demersal-zone-20260505-0
summary:
The demersal zone (from Latin demergere, "to sink") is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of the larger profundal zone. Being just above the ocean floor, the demersal zone is variable in depth and can be part of the photic zone where light can penetrate, and photosynthetic organisms grow, or the aphotic zone, which begins between depths of roughly 200 and 1,000 m (700 and 3,300 ft) and extends to the ocean depths, where no light penetrates. == Fish == The distinction between demersal species of fish and pelagic species is not always clear cut. The Atlantic cod (Gadus morhua) is a typical demersal fish, but can also be found in the open water column, and the Atlantic herring (Clupea harengus) is predominantly a pelagic species but forms large aggregations near the seabed when it spawns on banks of gravel. Two types of fish inhabit the demersal zone: those that are heavier than water and rest on the seabed, and those that have neutral


id: fracture-zone-20260505-0
file: data/en.wikipedia.org/wiki/Fracture_zone-0.md
category: reference
title: Fracture zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fracture_zone
date_saved: 2026-05-05T07:34:52.674187+00:00
instance: kb-cron
parent: fracture-zone-20260505-0
summary:
A fracture zone is a linear feature on the ocean floor—often hundreds, even thousands of kilometers long—resulting from the action of offset mid-ocean ridge axis segments. They are a consequence of plate tectonics. Lithospheric plates on either side of an active transform fault move in opposite directions; here, strike-slip activity occurs. Fracture zones extend past the transform faults, away from the ridge axis; are usually seismically inactive (because both plate segments are moving in the same direction), although they can display evidence of transform fault activity, primarily in the different ages of the crust on opposite sides of the zone. In actual usage, many transform faults aligned with fracture zones are often loosely referred to as "fracture zones" although technically, they are not. They can be associated with other tectonic features and may be subducted or distorted by later tectonic activity. They are usually defined with bathymetric, gravity and magnetic studies. == Structure and formation == Mid-ocean ridges are divergent plate boundaries. As the plates on either side of an offset mid-ocean ridge move, a transform fault forms at the offset between the two ridges. Fracture zones and the transform faults that form them are separate but related features. Transform


id: gas-hydrate-stability-zone-20260505-0
file: data/en.wikipedia.org/wiki/Gas_hydrate_stability_zone-0.md
category: reference
title: Gas hydrate stability zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Gas_hydrate_stability_zone
date_saved: 2026-05-05T07:34:53.961204+00:00
instance: kb-cron
parent: gas-hydrate-stability-zone-20260505-0
summary:
Gas hydrate stability zone, abbreviated GHSZ, also referred to as methane hydrate stability zone (MHSZ) or hydrate stability zone (HSZ), refers to a zone and depth of the marine environment at which methane clathrates naturally exist in the Earth's crust. == Description == Gas hydrate stability primarily depends upon temperature and pressure, however other variables such as gas composition and ionic impurities in water influence stability boundaries. The existence and depth of a hydrate deposit is often indicated by the presence of a bottom-simulating reflector (BSR). A BSR is a seismic reflection indicating the lower limit of hydrate stability in sediments due to the different densities of hydrate saturated sediments, normal sediments and those containing free gas. == Limits == The upper and lower limits of the HSZ, as well as its thickness, depend upon the local conditions in which the hydrate occurs. The conditions for hydrate stability generally restrict natural deposits to polar regions and deep oceanic regions. In polar regions, due to low temperatures, the upper limit of the hydrate stability zone occurs at a depth of approximately 150 meters.1 The maximal depth of the hydrate stability zone is limited by the geothermal gradient. Along continental margins the


id: hadal-zone-20260505-0
file: data/en.wikipedia.org/wiki/Hadal_zone-0.md
category: reference
title: Hadal zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hadal_zone
date_saved: 2026-05-05T07:34:56.432817+00:00
instance: kb-cron
parent: hadal-zone-20260505-0
summary:
The hadal zone, also known as the hadopelagic zone, is the deepest region of the ocean, lying within oceanic trenches. The hadal zone ranges from around 6 to 11 km (3.7 to 6.8 mi; 20,000 to 36,000 ft) below sea level, and exists in long, narrow, topographic V-shaped depressions. The total area occupied by the 46 individual hadal habitats worldwide is less than 0.25% of the world's seafloor, yet trenches account for over 40% of the ocean's depth range. Most hadal habitats are found in the Pacific Ocean, the largest and deepest of the conventional oceanic divisions. == Terminology and definition == Historically, the hadal zone was not recognized as distinct from the abyssal zone, although the deepest sections were sometimes called "ultra-abyssal". During the early 1950s, the Danish Galathea II and Soviet Vityaz expeditions separately discovered a distinct shift in the life at depths of 6,000–7,000 m (20,000–23,000 ft) not recognized by the broad definition of the abyssal zone. The term "hadal" was first proposed in 1956 by Anton Frederik Bruun to describe the parts of the ocean deeper than 6,000 m (20,000 ft), leaving abyssal for the parts at 4,000–6,000 m (13,000–20,000 ft). The name refers to Hades,


id: hadal-zone-20260505-1
file: data/en.wikipedia.org/wiki/Hadal_zone-1.md
category: reference
title: Hadal zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hadal_zone
date_saved: 2026-05-05T07:34:56.432817+00:00
instance: kb-cron
parent: hadal-zone-20260505-0
summary:
== Exploration == The exploration of the hadal zone requires the use of instruments that are able to withstand pressures of up to a thousand or more atmospheres. A few haphazard and non-standard tools have been used to collect limited, but valuable, information about the basic biology of a few hadal organisms. Manned and unmanned submersibles, however, can be used to study the depths in greater detail. Unmanned robotic submersibles may be remotely operated (connected to the research vessel by a cable) or autonomous (freely moving). Cameras and manipulators on submersibles allow researchers to observe and take samples of sediment and organisms. Failures of submersibles under the immense pressure at hadal zone depths have occurred. HROV Nereus is thought to have imploded at a depth of 9,990 meters while exploring the Kermadec Trench in 2014. == Notable missions == The first manned exploration to reach Challenger Deep, the deepest known part of the ocean located in the Mariana Trench, was accomplished in 1960 by Jacques Piccard and Don Walsh. They reached a maximum depth of 10,911 metres (35,797 ft) in the bathyscaphe Trieste. James Cameron also reached the bottom of Mariana Trench in March 2012 using the Deepsea Challenger. The


id: haff-lagoon-20260505-0
file: data/en.wikipedia.org/wiki/Haff_(lagoon)-0.md
category: reference
title: Haff (lagoon)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haff_(lagoon)
date_saved: 2026-05-05T07:34:57.591702+00:00
instance: kb-cron
parent: haff-lagoon-20260505-0
summary:
Haff (German for "lagoon", pronounced [haf] ) or Bodden may refer to several estuarine lagoons along the Southern Baltic coast: Frisches Haff Großes Haff Kamieński Lagoon or Camminer Bodden Kleines Haff Kurisches Haff Stettiner Haff, also Pommersches Haff or Oderhaff In Northern Germany and the Netherlands, the now obsolete Frisian word hef may refer to the Wadden Sea, which has some properties of a lagoon.


id: iceberg-20260505-0
file: data/en.wikipedia.org/wiki/Iceberg-0.md
category: reference
title: Iceberg
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Iceberg
date_saved: 2026-05-05T07:34:58.808748+00:00
instance: kb-cron
parent: iceberg-20260505-0
summary:
An iceberg is a piece of fresh water ice more than 15 meters (16 yards) long that has broken off a glacier or an ice shelf and is floating freely in open water. Smaller chunks of floating glacially derived ice are called "growlers" or "bergy bits". Much of an iceberg is below the water's surface, which led to the expression "tip of the iceberg" to illustrate a small part of a larger unseen issue. Icebergs are considered a serious maritime hazard. Icebergs vary considerably in size and shape. Icebergs that calve from glaciers in Greenland are often irregularly shaped while Antarctic ice shelves often produce large tabular (table top) icebergs. The largest iceberg in recent history, named B-15, was measured at nearly 300 by 40 kilometres (186 by 25 mi) in 2000. The largest iceberg on record was an Antarctic tabular iceberg measuring 335 by 97 kilometres (208 by 60 mi) sighted 240 kilometres (150 mi) west of Scott Island, in the South Pacific Ocean, by the USS Glacier on November 12, 1956. This iceberg was larger than Belgium. == Etymology == The word iceberg is a partial loan translation from the Dutch word ijsberg, literally meaning ice mountain, cognate


id: iceberg-20260505-1
file: data/en.wikipedia.org/wiki/Iceberg-1.md
category: reference
title: Iceberg
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Iceberg
date_saved: 2026-05-05T07:34:58.808748+00:00
instance: kb-cron
parent: iceberg-20260505-0
summary:
=== Stability === An iceberg may flip, or capsize, as it melts and breaks apart, changing the center of gravity. Capsizing can occur shortly after calving when the iceberg is young and establishing balance. Icebergs are unpredictable and can capsize anytime and without warning. Large icebergs that break off from a glacier front and flip onto the glacier face can push the entire glacier backwards momentarily, producing 'glacial earthquakes' that generate as much energy as an atomic bomb. === Color === Icebergs are generally white because they are covered in snow, but can be green, blue, yellow, black, striped, or even rainbow-colored. Seawater, algae and lack of air bubbles in the ice can create diverse colors. Sediment can create the dirty black coloration present in some icebergs. === Shape === In addition to size classification, icebergs can be classified on the basis of their shapes. The two basic types of iceberg forms are tabular and non-tabular. Tabular icebergs have steep sides and a flat top, much like a plateau, with a length-to-height ratio of more than 5:1. This type of iceberg, also known as an ice island, can be quite large, as in the case of Pobeda Ice Island. Antarctic


id: iceberg-20260505-2
file: data/en.wikipedia.org/wiki/Iceberg-2.md
category: reference
title: Iceberg
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Iceberg
date_saved: 2026-05-05T07:34:58.808748+00:00
instance: kb-cron
parent: iceberg-20260505-0
summary:
=== Commercial use === The idea of towing large icebergs to other regions as a source of water has been raised since at least the 1950s, without having been put into practice. In 2017, a business from the UAE announced plans to tow an iceberg from Antarctica to the Middle East; in 2019 salvage engineer Nick Sloane announced a plan to move one to South Africa at an estimated cost of $200 million. In 2019, a German company, Polewater, announced plans to tow Antarctic icebergs to places like South Africa. Companies have used iceberg water in products such as bottled water, fizzy ice cubes and alcoholic drinks. For example, Iceberg Beer by Quidi Vidi Brewing Company is made from icebergs found around St. John's, Newfoundland. Although annual iceberg supply in Newfoundland and Labrador exceeds the total freshwater consumption of the United States, in 2016 the province introduced a tax on iceberg harvesting and imposed a limit on how much fresh water can be exported yearly. == Oceanography and ecology == The freshwater injected into the ocean by melting icebergs can change the density of the seawater in the vicinity of the iceberg. Fresh melt water released at depth is lighter,


id: intertidal-zone-20260505-0
file: data/en.wikipedia.org/wiki/Intertidal_zone-0.md
category: reference
title: Intertidal zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Intertidal_zone
date_saved: 2026-05-05T07:35:11.460624+00:00
instance: kb-cron
parent: intertidal-zone-20260505-0
summary:
The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various species of life, such as sea stars, sea urchins, and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the littoral zone or seashore, although those can be defined as a wider region. The intertidal zone also includes steep rocky cliffs, sandy beaches, bogs or wetlands (e.g., vast mudflats). This area can be a narrow strip, such as in Pacific islands that have only a narrow tidal range, or can include many meters of shoreline where shallow beach slopes interact with high tidal excursion. The peritidal zone is similar but somewhat wider, extending from above the highest tide level to below the lowest. Organisms in the intertidal zone are well-adapted to their environment, facing high levels of interspecific competition and the rapidly changing conditions that come with the tides. The intertidal zone is also home to several species from many different phyla (Porifera, Annelida, Coelenterata, Mollusca, Arthropoda, etc.). The water


id: intertidal-zone-20260505-1
file: data/en.wikipedia.org/wiki/Intertidal_zone-1.md
category: reference
title: Intertidal zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Intertidal_zone
date_saved: 2026-05-05T07:35:11.460624+00:00
instance: kb-cron
parent: intertidal-zone-20260505-0
summary:
The intertidal region is an important model system for the study of ecology, especially on wave-swept rocky shores. The region contains a high diversity of species, and the zonation created by the tides causes species ranges to be compressed into very narrow bands. This makes it relatively simple to study species across their entire cross-shore range, something that can be extremely difficult in, for instance, terrestrial habitats that can stretch thousands of kilometres. Communities on wave-swept shores also have high turnover due to disturbance, so it is possible to watch ecological succession over years rather than decades. The burrowing invertebrates that make up large portions of sandy beach ecosystems are known to travel relatively great distances in cross-shore directions as beaches change on the order of days, semilunar cycles, seasons, or years. The distribution of some species has been found to correlate strongly with geomorphic datums such as the high tide strand and the water table outcrop. Since the foreshore is alternately covered by the sea and exposed to the air, organisms living in this environment must be adapted to both wet and dry conditions. Intertidal zone biomass reduces the risk of shoreline erosion from high intensity waves. Typical inhabitants


id: island-20260505-0
file: data/en.wikipedia.org/wiki/Island-0.md
category: reference
title: Island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Island
date_saved: 2026-05-05T07:35:12.739706+00:00
instance: kb-cron
parent: island-20260505-0
summary:
An island or isle is a piece of land, distinct from a continent, completely surrounded by water. There are continental islands, which were formed by being split from a continent by plate tectonics, and oceanic islands, which have never been part of a continent. Oceanic islands can be formed from volcanic activity, grow into atolls from coral reefs, and form from sediment along shorelines, creating barrier islands. River islands can also form from sediment and debris in rivers. Artificial islands are those made by humans, including small rocky outcroppings built out of lagoons and large-scale land reclamation projects used for development. Islands are host to diverse plant and animal life. Oceanic islands have the sea as a natural barrier to the introduction of new species, causing the species that do reach the island to evolve in isolation. Continental islands share animal and plant life with the continent they split from. Depending on how long ago the continental island formed, the life on that island may have diverged greatly from the mainland due to natural selection. Humans have lived on and traveled between islands for thousands of years at a minimum. Some islands became host to humans due to a land


id: island-20260505-1
file: data/en.wikipedia.org/wiki/Island-1.md
category: reference
title: Island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Island
date_saved: 2026-05-05T07:35:12.739706+00:00
instance: kb-cron
parent: island-20260505-0
summary:
=== Formation in freshwater === A fluvial island is an island that forms from the erosion and sedimentation of debris in rivers; almost all rivers have some form of fluvial islands. These islands may only be a few meters high, and are usually temporary. Changes in the flow speed, water level, and sediment content of the river may affect the rate of fluvial island formation and depletion. Permanent river islands also exist, the largest of which (that is completely inland) is Bananal Island in the Tocantins of Brazil, which has a maximum width of 55 kilometers. Lakes form for a variety of reasons, including glaciers, plate tectonics, and volcanism. Lake islands can form as part of these processes. == Life on islands == The field of insular biogeography studies the ecological processes that take place on islands, with a focus on what factors effect the evolution, extinction, and richness of species. Scientists often study islands as an isolated model of how the process of natural selection takes place. Island ecology studies organisms on islands and their environment. It has yielded important insights for its parent field of ecology since the time of Charles Darwin. === Endemism === In biology, endemism


id: island-20260505-2
file: data/en.wikipedia.org/wiki/Island-2.md
category: reference
title: Island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Island
date_saved: 2026-05-05T07:35:12.739706+00:00
instance: kb-cron
parent: island-20260505-0
summary:
Species endemic to islands show a common evolutionary trajectory. Foster's rule (also known as the island rule), states that small mammals such as rodents evolve to become larger, known as island gigantism. One such example is the giant tortoise of the Seychelles, though it is unknown if it grew in size before or after reaching the island. Larger animals such as the hippopotamus tend to become smaller, such as in the case of the pygmy hippopotamus. This is known as insular dwarfism. In the case of smaller animals, it has been hypothesized that animals on islands may have fewer predators and competitors, resulting in selection pressure towards larger animals. Larger animals may exhaust food resources quickly due to their size, causing malnutrition in their young, resulting in a selection pressure for smaller animals that require less food. Having fewer predators would mean these animals did not need not be large to survive. === Darwin, the Galápagos, and natural selection === Charles Darwin formulated the theory of natural selection through the study of island ecology. The species he observed on the Galápagos Islands, including tanager birds, contributed to his understanding of how evolution works. He first traveled to the islands as


id: island-20260505-3
file: data/en.wikipedia.org/wiki/Island-3.md
category: reference
title: Island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Island
date_saved: 2026-05-05T07:35:12.739706+00:00
instance: kb-cron
parent: island-20260505-0
summary:
==== Diet ==== The Polynesian diet got most of its protein from fishing. Polynesians were known to fish close to shore, as well as in deep water. It was reported that Rapa Nui people were known to fish as far as 500 km (310 mi) from shore at coral reefs. Spear, line, and net fishing were all used, to catch tuna as well as sharks and stingrays. Island cultures also cultivate native and non-native crops. Polynesians grew the native yam, taro, breadfruit, banana, coconut and other fruits and vegetables. Different island climates made different resources more important, such as the Hawaiian islands being home to irrigated fields of taro, whereas in some islands, like Tahiti, breadfruit was more widely cultivated and fermented in order to preserve it. There is archeological evidence that Canary Islanders would chew the roots of ferns for sustenance, a practice that wore heavily on their molars. These islanders would also grow barley and raised livestock such as goats. === Island nations and territories === Many island nations have little land and a restricted set of natural resources. However, these nations control some of the largest fisheries in the world, deposits of copper, gold, and nickel, as


id: island-20260505-4
file: data/en.wikipedia.org/wiki/Island-4.md
category: reference
title: Island
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Island
date_saved: 2026-05-05T07:35:12.739706+00:00
instance: kb-cron
parent: island-20260505-0
summary:
For hundreds of years, islands have been created through land reclamation. One of the first recorded instances of this when people of the Solomon Islands created eighty such islands by piling coral and rock in the Lau Lagoon. However, the first permanent artificial island is Al-Sayah island, in Bahrain – created at least 1,200 years ago. One traditional way of constructing islands is with the use of a revetment. Sandbags or stones are dropped with a barge into the sea to bring the land level slightly out of the water. The island area is then filled with sand or gravel, followed by a construction of this revetment to hold it together. Islands have also been constructed with a permanent caisson, a steel or concrete structure built in a closed loop and then filled with sand. Some modern islands have been constructed by pouring millions of tons of sand into the sea, such as with Pearl Island in Qatar or the Palm Islands in Dubai. These islands are usually created for real estate development, and are sold for private ownership or construction of housing. Offshore oil platforms have also been described as a type of island. Some atolls have been covered


id: kinematic-wave-20260505-0
file: data/en.wikipedia.org/wiki/Kinematic_wave-0.md
category: reference
title: Kinematic wave
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Kinematic_wave
date_saved: 2026-05-05T07:35:13.990990+00:00
instance: kb-cron
parent: kinematic-wave-20260505-0
summary:
In gravity and pressure driven fluid dynamical and geophysical mass flows such as ocean waves, avalanches, debris flows, mud flows, flash floods, etc., kinematic waves are important mathematical tools to understand the basic features of the associated wave phenomena. These waves are also applied to model the motion of highway traffic flows. In these flows, mass and momentum equations can be combined to yield a kinematic wave equation. Depending on the flow configurations, the kinematic wave can be linear or non-linear, which depends on whether the wave phase speed is a constant or a variable. A kinematic wave can be described by a simple partial differential equation with a single unknown field variable (e.g., the flow or wave height, h {\displaystyle h} ) in terms of the two independent variables, namely the time ( t {\displaystyle t} ) and the space ( x {\displaystyle x} ) with some parameters (coefficients) containing information about the physics and geometry of the flow. In general, the wave can be advecting and diffusing. However, in simple situations, the kinematic wave is mainly advecting. == Kinematic wave for debris flow == Non-linear kinematic wave for debris flow can be written as follows with complex non-linear


id: knoll-oceanography-20260505-0
file: data/en.wikipedia.org/wiki/Knoll_(oceanography)-0.md
category: reference
title: Knoll (oceanography)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Knoll_(oceanography)
date_saved: 2026-05-05T07:35:15.200691+00:00
instance: kb-cron
parent: knoll-oceanography-20260505-0
summary:
In marine geology, a knoll is defined as a rounded underwater hill, not exceeding 1000 meters in height. Any rounded underwater features exceeding that height are referred to as seamounts. They are believed to cover around 16.3% of the world's seafloor. == Examples == Orphan Knoll Graveyard Seamounts == References ==


id: lagoon-20260505-0
file: data/en.wikipedia.org/wiki/Lagoon-0.md
category: reference
title: Lagoon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Lagoon
date_saved: 2026-05-05T07:35:16.460249+00:00
instance: kb-cron
parent: lagoon-20260505-0
summary:
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as a reef, a barrier island or islands, a barrier peninsula, or an isthmus. Lagoons are commonly divided into coastal lagoons (or barrier lagoons) and atoll lagoons. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around many parts of the world. == Definition and terminology == Lagoons are shallow, often elongated bodies of water separated from a larger body of water by a shallow or exposed shoal, coral reef, or similar feature. Some authorities include fresh water bodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree of salinity. The distinction between "lagoon" and "estuary" also varies between authorities. Richard A. Davis Jr. restricts "lagoon" to bodies of water with little or no fresh water inflow, and little or no tidal flow, and calls any bay that receives a regular flow of fresh water an "estuary". Davis does state that the terms "lagoon" and


id: littoral-zone-20260505-0
file: data/en.wikipedia.org/wiki/Littoral_zone-0.md
category: reference
title: Littoral zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Littoral_zone
date_saved: 2026-05-05T07:35:17.722778+00:00
instance: kb-cron
parent: littoral-zone-20260505-0
summary:
The littoral zone, also called litoral or nearshore, is the part of an ocean, sea, lake, or river, that is close to the shore. It provides extensive and productive habitats around the world, adjacent to land-water interfaces. In coastal ecology, the littoral zone includes the foreshore (intertidal zone) extending from the high water mark (which is rarely inundated) to the low water mark (where coastal areas become permanently submerged). However, the geographical meaning of littoral zone extends well beyond the intertidal zone to include all neritic waters within the bounds of continental shelves. Continental shelves cover an area of about 7% of the surface area of the oceans. In lake ecosystems, the littoral zone covers about 78% of Earth's total lake area. These zones support abundant plant growth, making them not only structurally distinct from the pelagic (open water) zone but also highly productive. Productivity in both marine and lake littoral zones can reach levels comparable to tropical rainforests. == Definitions and characteristics == The littoral zone has no single definition. What is regarded as the full extent of the littoral zone, and the way the littoral zone is divided into subregions, varies in different contexts. For lakes, the littoral


id: littoral-zone-20260505-1
file: data/en.wikipedia.org/wiki/Littoral_zone-1.md
category: reference
title: Littoral zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Littoral_zone
date_saved: 2026-05-05T07:35:17.722778+00:00
instance: kb-cron
parent: littoral-zone-20260505-0
summary:
The sublittoral zone starts immediately below the eulittoral zone. This zone is permanently covered with seawater and is approximately equivalent to the neritic zone. In physical oceanography, the sublittoral zone refers to coastal regions with significant tidal flows and energy dissipation, including non-linear flows, internal waves, river outflows and oceanic fronts. In practice, this typically extends to the edge of the continental shelf, with depths around 200 meters. In marine biology, the sublittoral zone refers to the areas where sunlight reaches the ocean floor, that is, where the water is never so deep as to take it out of the photic zone. This results in high primary production and makes the sublittoral zone the location of the majority of sea life. As in physical oceanography, this zone typically extends to the edge of the continental shelf. The benthic zone in the sublittoral is much more stable than in the intertidal zone; temperature, water pressure, and the amount of sunlight remain fairly constant. Sublittoral corals do not have to deal with as much change as intertidal corals. Corals can live in both zones, but they are more common in the sublittoral zone. Within the sublittoral, marine biologists also identify the following:


id: littoral-zone-20260505-2
file: data/en.wikipedia.org/wiki/Littoral_zone-2.md
category: reference
title: Littoral zone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Littoral_zone
date_saved: 2026-05-05T07:35:17.722778+00:00
instance: kb-cron
parent: littoral-zone-20260505-0
summary:
Many vertebrates (e.g., mammals, waterfowl, reptiles) and invertebrates (insects, etc.) use both the littoral zone as well as the terrestrial ecosystem for food and habitat. Biota that are commonly assumed to reside in the pelagic zone often rely heavily on resources from the littoral zone. Littoral areas of ponds and lakes are typically better oxygenated, structurally more complex, and afford more abundant and diverse food resources than do profundal sediments. All these factors lead to a high diversity of insects and very complex trophic interactions. The great lakes of the world represent a global heritage of surface freshwater and aquatic biodiversity. Species lists for 14 of the world's largest lakes reveal that 15% of the global diversity (the total number of species) of freshwater fishes, 9% of non-insect freshwater invertebrate diversity, and 2% of aquatic insect diversity live in this handful of lakes. The vast majority (more than 93%) of species inhabit the shallow, nearshore littoral zone, and 72% are completely restricted to the littoral zone, even though littoral habitats are a small fraction of total lake areas. Because the littoral zone is important for many recreational and industrial purposes, it is often severely affected by many human activities that


id: longhurst-code-20260505-0
file: data/en.wikipedia.org/wiki/Longhurst_code-0.md
category: reference
title: Longhurst code
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Longhurst_code
date_saved: 2026-05-05T07:35:18.907502+00:00
instance: kb-cron
parent: longhurst-code-20260505-0
summary:
Longhurst code refers to a set of geospatial four-letter geocodes for referencing geographic regions in oceanography. The set of 56 geocodes represent biogeochemical provinces that partition the pelagic environment. It is assumed that each province represents a unique set of environmental conditions. They are named after Alan R. Longhurst, the author of "Ecological Geography of the Sea", the textbook in which these codes are defined. These codes have also been used in bioinformatic databases such as IMGTooltip Integrated Microbial Genomes to represent sample origins for sequenced microbial genomes, as a supplement to latitude and longitude coordinate metrics. == References ==


id: longshore-drift-20260505-0
file: data/en.wikipedia.org/wiki/Longshore_drift-0.md
category: reference
title: Longshore drift
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Longshore_drift
date_saved: 2026-05-05T07:35:20.233864+00:00
instance: kb-cron
parent: longshore-drift-20260505-0
summary:
Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand, shingle, shells) along a coast parallel to the shoreline, which is dependent on the angle of incoming wave direction. Oblique incoming wind squeezes water along the coast, generating a water current that moves parallel to the coast. Longshore drift is simply the sediment moved by the longshore current. This current and sediment movement occurs within the surf zone. The process is also known as littoral drift. Beach sand is also moved on such oblique wind days, due to the swash and backwash of water on the beach. Breaking surf sends water up the coast (swash) at an oblique angle and gravity then drains the water straight downslope (backwash) perpendicular to the shoreline. Thus beach sand can move downbeach in a sawtooth fashion many tens of meters (yards) per day. This process is called "beach drift", but some workers regard it as simply part of "longshore drift" because of the overall movement of sand parallel to the coast. Longshore drift affects numerous sediment sizes as it works in slightly different ways depending on the sediment (e.g. the difference in long-shore drift


id: longshore-drift-20260505-1
file: data/en.wikipedia.org/wiki/Longshore_drift-1.md
category: reference
title: Longshore drift
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Longshore_drift
date_saved: 2026-05-05T07:35:20.233864+00:00
instance: kb-cron
parent: longshore-drift-20260505-0
summary:
=== The sediment budget === The sediment budget takes into consideration sediment sources and sinks within a system. This sediment can come from any source with examples of sources and sinks consisting of: Rivers Lagoons Eroding land sources Artificial sources e.g. nourishment Artificial sinks e.g. mining/extraction Offshore transport Deposition of sediment on shore Gullies through the land This sediment then enters the coastal system and is transported by longshore drift. A good example of the sediment budget and longshore drift working together in the coastal system is inlet ebb-tidal shoals, which store sand that has been transported by long-shore transport. As well as storing sand these systems may also transfer or by pass sand into other beach systems, therefore inlet ebb-tidal (shoal) systems provide good sources and sinks for the sediment budget. Sediment deposition throughout a shoreline profile conforms to the null point hypothesis; where gravitational and hydraulic forces determine the settling velocity of grains in a seaward fining sediment distribution. Long shore occurs in a 90 to 80 degree backwash so it would be presented as a right angle with the wave line. == Natural features == This section consists of features of longshore drift that occur on a


id: longshore-drift-20260505-2
file: data/en.wikipedia.org/wiki/Longshore_drift-2.md
category: reference
title: Longshore drift
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Longshore_drift
date_saved: 2026-05-05T07:35:20.233864+00:00
instance: kb-cron
parent: longshore-drift-20260505-0
summary:
Groynes are shore protection structures, placed at equal intervals along the coastline in order to stop coastal erosion and generally cross the intertidal zone. Due to this, groyne structures are usually used on shores with low net and high annual longshore drift in order to retain the sediments lost in storm surges and further down the coast. There are numerous variations to groyne designs with the three most common designs consisting of: zig-zag groynes, which dissipate the destructive flows that form in wave-induced currents or in breaking waves. T-head groynes, which reduce wave height through wave diffraction. ‘Y’ head, a fish-tail groyne system. === Artificial headlands === Artificial headlands are also shore protection structures, which are created in order to provide a certain amount of protection to beaches or bays. Although the creation of headlands involves accretion of sediments on the up-drift side of the headland and moderate erosion of the down-drift end of the headland, this is undertaken in order to design a stabilised system that allows material to accumulate in beaches further along the shore. Artificial headlands can occur due to natural accumulation or also through artificial nourishment. === Detached breakwaters === Detached breakwaters are shore protection structures,


id: lower-oceanic-crust-20260505-0
file: data/en.wikipedia.org/wiki/Lower_oceanic_crust-0.md
category: reference
title: Lower oceanic crust
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Lower_oceanic_crust
date_saved: 2026-05-05T07:35:21.427862+00:00
instance: kb-cron
parent: lower-oceanic-crust-20260505-0
summary:
The lower oceanic crust is the lower part of the oceanic crust and represents the major part of it (the largest part by volume). It is generally located 4–8 km below the ocean floor and the major lithologies are mafic (ultramafic and gabbroic rocks) which derive from melts rising from the Earth's mantle. This part of the oceanic crust is an important zone for processes such as melt accumulation and melt modification (fractional crystallisation and crustal assimilation). The recycling of this part of the oceanic crust, together with the upper mantle has been suggested as a significant source component for tholeiitic magmas in Hawaiian volcanoes. Although the lower oceanic crust builds the link between the mantle and the MORB, and can't be neglected for the understanding of MORB evolution, the complex processes operating in this zone remain unclear and there is an ongoing debate in Earth Sciences about this. It is 6KM long. == Processes == The lower oceanic crust connects the Earth's mantle with the MORB, where around 60% of the total magma production of the Earth happens. The three main processes happening in this region of the oceanic crust are partial melting of the Earth's mantle, melt accumulation


id: mangrove-20260505-0
file: data/en.wikipedia.org/wiki/Mangrove-0.md
category: reference
title: Mangrove
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mangrove
date_saved: 2026-05-05T07:35:22.795957+00:00
instance: kb-cron
parent: mangrove-20260505-0
summary:
A mangrove is a shrub or tree that grows mainly in coastal saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen and remove salt, allowing them to tolerate conditions that kill most plants. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse due to convergent evolution in several plant families. They occur worldwide in tropical and subtropical coastal areas, mainly between latitudes 30° N and 30° S, with the greatest mangrove area within 5° of the equator. Mangrove plant families first appeared during the Late Cretaceous to Paleocene epochs and became widely distributed in part due to the movement of tectonic plates. The oldest known fossils of mangrove palm date to 75 million years ago. Mangroves are salt-tolerant (halophytic) and are adapted to live in harsh coastal conditions. They contain a complex salt filtration system and a complex root system to cope with saltwater immersion and wave action. They are adapted to the low-oxygen conditions of waterlogged mud, but are most likely to thrive in the upper half of the intertidal zone. The mangrove biome, often


id: mangrove-20260505-1
file: data/en.wikipedia.org/wiki/Mangrove-1.md
category: reference
title: Mangrove
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mangrove
date_saved: 2026-05-05T07:35:22.795957+00:00
instance: kb-cron
parent: mangrove-20260505-0
summary:
=== Limiting salt intake === Red mangroves exclude salt by having significantly impermeable roots that are highly suberised (impregnated with suberin), acting as an ultrafiltration mechanism to exclude sodium salts from the rest of the plant. One study found that roots of the Indian mangrove Avicennia officinalis exclude 90% to 95% of the salt in water taken up by the plant, depositing the excluded salt in the cortex of the root. An increase in the production of suberin and in the activity of a gene regulating cytochrome P450 were observed in correlation with an increase in the salinity of the water to which the plant was exposed. In a frequently cited concept that has become known as the "sacrificial leaf", salt which does accumulate in the shoot (sprout) then concentrates in old leaves, which the plant then sheds. However, recent research on the Red mangrove Rhizophora mangle suggests that the older, yellowing leaves have no more measurable salt content than the other, greener leaves. === Limiting water loss === Because of the limited fresh water available in salty intertidal soils, mangroves limit the amount of water they lose through their leaves. They can restrict the opening of their stomata (pores


id: mangrove-20260505-2
file: data/en.wikipedia.org/wiki/Mangrove-2.md
category: reference
title: Mangrove
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mangrove
date_saved: 2026-05-05T07:35:22.795957+00:00
instance: kb-cron
parent: mangrove-20260505-0
summary:
"At the limits of distribution, the formation is represented by scrubby, usually monotypic Avicennia-dominated vegetation, as at Westonport Bay and Corner Inlet, Victoria, Australia. The latter locality is the highest latitude (38° 45'S) at which mangroves occur naturally. The mangroves in New Zealand, which extend as far south as 37°, are of the same type; they start as low forest in the northern part of the North Island but become low scrub toward their southern limit. In both instances, the species is referred to as Avicennia marina var. australis, although genetic comparison is clearly needed. In Western Australia, A. marina extends as far south as Bunbury (33° 19'S). In the northern hemisphere, scrubby Avicennia gerrninans in Florida occurs as far north as St. Augustine on the east coast and Cedar Point on the west. There are records of A. germinans and Rhizophora mangle for Bermuda, presumably supplied by the Gulf Stream. In southern Japan, Kandelia obovata occurs to about 31 °N (Tagawa in Hosakawa et al., 1977, but initially referred to as K. candel)." == Mangrove forests == Mangrove forests, also called mangrove swamps or mangals, are found in tropical and subtropical tidal areas. Areas where mangroves occur include estuaries


id: mangrove-20260505-3
file: data/en.wikipedia.org/wiki/Mangrove-3.md
category: reference
title: Mangrove
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mangrove
date_saved: 2026-05-05T07:35:22.795957+00:00
instance: kb-cron
parent: mangrove-20260505-0
summary:
Once established, mangrove roots provide an oyster habitat and slow water flow, thereby enhancing sediment deposition in areas where it is already occurring. The fine, anoxic sediments under mangroves act as sinks for a variety of heavy (trace) metals which colloidal particles in the sediments have concentrated from the water. Mangrove removal disturbs these underlying sediments, often creating problems of trace metal contamination of seawater and organisms of the area. Mangrove swamps protect coastal areas from erosion, storm surge (especially during tropical cyclones), and tsunamis. They limit high-energy wave erosion mainly during events such as storm surges and tsunamis. The mangroves' massive root systems are efficient at dissipating wave energy. Likewise, they slow down tidal water so that its sediment is deposited as the tide comes in, leaving all except fine particles when the tide ebbs. In this way, mangroves build their environments. Because of the uniqueness of mangrove ecosystems and the protection against erosion they provide, they are often the object of conservation programs, including national biodiversity action plans. The unique ecosystem found in the intricate mesh of mangrove roots offers a quiet marine habitat for young organisms. In areas where roots are permanently submerged, the organisms they host


id: mangrove-20260505-4
file: data/en.wikipedia.org/wiki/Mangrove-4.md
category: reference
title: Mangrove
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mangrove
date_saved: 2026-05-05T07:35:22.795957+00:00
instance: kb-cron
parent: mangrove-20260505-0
summary:
Mangrove roots harbour a repertoire of microbial taxa that contribute to important ecological functions in mangrove ecosystems. Like typical terrestrial plants, mangroves depend upon mutually beneficial interactions with microbial communities. In particular, microbes residing in developed roots could help mangroves transform nutrients into usable forms before plant assimilation. These microbes also provide mangroves phytohormones for suppressing phytopathogens or helping mangroves withstand heat and salinity. In turn, root-associated microbes receive carbon metabolites from the plant via root exudates, thus close associations between the plant and microbes are established for their mutual benefits. The taxonomic class level shows that most Proteobacteria were reported to come from Gammaproteobacteria, followed by Deltaproteobacteria and Alphaproteobacteria. The diverse function and the phylogenic variation of Gammaproteobacteria, which consisted of orders such as Alteromonadales and Vibrionales, are found in marine and coastal regions and are high in abundance in mangrove sediments functioning as nutrient recyclers. Members of Deltaproteobacteria found in mangrove soil are mostly sulfur-related, consisting of Desulfobacterales, Desulfuromonadales, Desulfovibrionales, and Desulfarculales among others. Highly diverse microbial communities (mainly bacteria and fungi) have been found to inhabit and function in mangrove roots. For example, diazotrophic bacteria in the vicinity of mangrove roots could perform biological nitrogen fixation, which


id: mangrove-20260505-5
file: data/en.wikipedia.org/wiki/Mangrove-5.md
category: reference
title: Mangrove
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mangrove
date_saved: 2026-05-05T07:35:22.795957+00:00
instance: kb-cron
parent: mangrove-20260505-0
summary:
Mangrove forests are one of the most carbon-rich biomes, accounting for 11% of the total input of terrestrial carbon into oceans. Viruses are thought to significantly influence local and global biogeochemical cycles, though as of 2019, little information was available about the community structure, genetic diversity, and ecological roles of viruses in mangrove ecosystems. Viruses are the most abundant biological entities on earth, present in virtually all ecosystems. By lysing their hosts, that is, by rupturing their cell membranes, viruses control host abundance and affect the structure of host communities. Viruses also influence their host diversity and evolution through horizontal gene transfer, selection for resistance and manipulation of bacterial metabolisms. Importantly, marine viruses affect local and global biogeochemical cycles through the release of substantial amounts of organic carbon and nutrients from hosts and assist microbes in driving biogeochemical cycles with auxiliary metabolic genes (AMGs). It is presumed that AMGs augment viral-infected host metabolism and facilitate the production of new viruses. AMGs have been extensively explored in marine cyanophages and include genes involved in photosynthesis, carbon turnover, phosphate uptake and stress response. Cultivation-independent metagenomic analysis of viral communities has identified additional AMGs that are involved in motility, central carbon metabolism, photosystem


id: mangrove-20260505-6
file: data/en.wikipedia.org/wiki/Mangrove-6.md
category: reference
title: Mangrove
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mangrove
date_saved: 2026-05-05T07:35:22.795957+00:00
instance: kb-cron
parent: mangrove-20260505-0
summary:
== Further reading == Saenger, Peter (2002). Mangrove Ecology, Silviculture, and Conservation. Kluwer Academic Publishers, Dordrecht. ISBN 1-4020-0686-1. Thanikaimoni, Ganapathi (1986). Mangrove Palynology UNDP/UNESCO and the French Institute of Pondicherry, ISSN 0073-8336 (E). Tomlinson, Philip B. (1986). The Botany of Mangroves. Cambridge University Press, Cambridge, ISBN 0-521-25567-8. Teas, H. J. (1983). Biology and Ecology of Mangroves. W. Junk Publishers, The Hague. ISBN 90-6193-948-8. Plaziat, Jean-Claude; Cavagnetto, Carla; Koeniguer, Jean-Claude; Baltzer, Frédéric (2001). "History and biogeography of the mangrove ecosystem, based on a critical reassessment of the paleontological record". Wetlands Ecology and Management. 9 (3): 161–180. Bibcode:2001WetEM...9..161P. doi:10.1023/A:1011118204434. S2CID 24980831. Jayatissa, L. P.; Dahdouh-Guebas, F.; Koedam, N. (2002). "A review of the floral composition and distribution of mangroves in Sri Lanka" (PDF). Botanical Journal of the Linnean Society. 138: 29–43. doi:10.1046/j.1095-8339.2002.00002.x. Ellison, Aaron M. (2000). "Mangrove Restoration: Do We Know Enough?". Restoration Ecology. 8 (3): 219–229. Bibcode:2000ResEc...8..219E. doi:10.1046/j.1526-100x.2000.80033.x. S2CID 86352384. Agrawala, Shardul; Hagestad; Marca; Koshy, Kayathu; Ota, Tomoko; Prasad, Biman; Risbey, James; Smith, Joel; Van Aalst, Maarten. 2003. Development and Climate Change in Fiji: Focus on Coastal Mangroves. Organisation of Economic Co-operation and Development, Paris, Cedex 16, France. Barbier, E. B.; Sathirathai, S. (2001). "Valuing Mangrove Conservation in Southern Thailand". Contemporary


id: marine-habitat-20260505-0
file: data/en.wikipedia.org/wiki/Marine_habitat-0.md
category: reference
title: Marine habitat
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Marine_habitat
date_saved: 2026-05-05T07:35:24.136463+00:00
instance: kb-cron
parent: marine-habitat-20260505-0
summary:
A marine habitat is a habitat that supports marine life. Marine life depends in some way on the saltwater that is in the sea (the term marine comes from the Latin mare, meaning sea or ocean). A habitat is an ecological or environmental area inhabited by one or more living species. The marine environment supports many kinds of these habitats. Marine habitats can be divided into coastal and open ocean habitats. Coastal habitats are found in the area that extends from as far as the tide comes in on the shoreline out to the edge of the continental shelf. Most marine life is found in coastal habitats, even though the shelf area occupies only seven percent of the total ocean area. Open ocean habitats are found in the deep ocean beyond the edge of the continental shelf. Alternatively, marine habitats can be divided into pelagic and demersal zones. Pelagic habitats are found near the surface or in the open water column, away from the bottom of the ocean. Demersal habitats are near or on the bottom of the ocean. An organism living in a pelagic habitat is said to be a pelagic organism, as in pelagic fish. Similarly, an organism


id: marine-habitat-20260505-1
file: data/en.wikipedia.org/wiki/Marine_habitat-1.md
category: reference
title: Marine habitat
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Marine_habitat
date_saved: 2026-05-05T07:35:24.136463+00:00
instance: kb-cron
parent: marine-habitat-20260505-0
summary:
In marine systems, ocean currents have a key role determining which areas are effective as habitats, since ocean currents transport the basic nutrients needed to support marine life. Plankton are the life forms that inhabit the ocean that are so small (less than 2 mm) that they cannot effectively propel themselves through the water, but must drift instead with the currents. If the current carries the right nutrients, and if it also flows at a suitably shallow depth where there is plenty of sunlight, then such a current itself can become a suitable habitat for photosynthesizing tiny algae called phytoplankton. These tiny plants are the primary producers in the ocean, at the start of the food chain. In turn, as the population of drifting phytoplankton grows, the water becomes a suitable habitat for zooplankton, which feed on the phytoplankton. While phytoplankton are tiny drifting plants, zooplankton are tiny drifting animals, such as the larvae of fish and marine invertebrates. If sufficient zooplankton establish themselves, the current becomes a candidate habitat for the forage fish that feed on them. And then if sufficient forage fish move to the area, it becomes a candidate habitat for larger predatory fish and other marine


