# kb

id: origin-of-dna-20260505-0
file: data/en.wikipedia.org/wiki/Origin_of_DNA-0.md
category: reference
title: Origin of DNA
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Origin_of_DNA
date_saved: 2026-05-05T10:00:11.447085+00:00
instance: kb-cron
parent: origin-of-dna-20260505-0
summary:
The Origin of DNA encompasses the scientific theories and discoveries surrounding the emergence of deoxyribonucleic acid (DNA) as the primary genetic material for all known forms of life. DNA contains the genetic information that allows organisms to function, grow, and reproduce. However, the exact timeline and mechanisms by which DNA assumed this role during the 4-billion-year history of life remain active areas of scientific inquiry. While the last universal common ancestor (LUCA) is thought to have possessed DNA, it is currently widely proposed that the earliest forms of life may have relied on RNA as their genetic material, with DNA evolving later as a more chemically stable repository for genetic information. == History == Research into the origins of DNA is fundamentally constrained by the lack of direct physical evidence of ancient genetic systems. Investigating the early evolution of nucleic acids is notoriously difficult because DNA survives in the natural environment for less than one million years. Once an organism dies, its DNA slowly degrades into short fragments in solution, making the recovery of DNA from most ancient fossils impossible. While claims for older DNA have been made in the literature, they are met with significant skepticism within the scientific


id: permanent-income-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Permanent_income_hypothesis-0.md
category: reference
title: Permanent income hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Permanent_income_hypothesis
date_saved: 2026-05-05T10:00:12.694267+00:00
instance: kb-cron
parent: permanent-income-hypothesis-20260505-0
summary:
The permanent income hypothesis (PIH) is a model in the field of economics to explain the formation of consumption patterns. It suggests consumption patterns are formed from future expectations and consumption smoothing. The theory was developed by Milton Friedman and published in his A Theory of the Consumption Function, published in 1957 and subsequently formalized by Robert Hall in a rational expectations model. Originally applied to consumption and income, the process of future expectations is thought to influence other phenomena. In its simplest form, the hypothesis states changes in permanent income (human capital, property, assets), rather than changes in temporary income (unexpected income), are what drive changes in consumption. The formation of consumption patterns opposite to predictions was an outstanding problem faced by the Keynesian orthodoxy. Friedman's predictions of consumption smoothing, where people spread out transitory changes in income over time, departed from the traditional Keynesian emphasis on a higher marginal propensity to consume out of current income. Income consists of a permanent (anticipated and planned) component and a transitory (unexpected and surprising) component. In the permanent income hypothesis model, the key determinant of consumption is an individual's lifetime income, not their current income. Unlike permanent income, transitory incomes are


id: permanent-income-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Permanent_income_hypothesis-1.md
category: reference
title: Permanent income hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Permanent_income_hypothesis
date_saved: 2026-05-05T10:00:12.694267+00:00
instance: kb-cron
parent: permanent-income-hypothesis-20260505-0
summary:
The permanent income hypothesis questions this ability of governments. However, it is also true that permanent income theory is concentrated mainly on long run dynamics and relations, while Keynes focused primarily on short run considerations. Friedman's argument, which challenged the use of fiscal policy in smoothing out business cycles, was challenged by stressing the relation between consumption and disposable income still follows (more or less) the mechanism supposed by Keynes. Friedman starts elaborating his theory under the assumption of complete certainty. Under such circumstances, for Friedman, two motives exist for a consumer unit to spend more or less on consumption than its income: The first is to smooth its consumption expenditures through appropriate timing of borrowing and lending; and the second is either to realize interest earnings on deposits if the relevant rate of interest is positive, or to benefit from borrowing if the interest rate is negative. According to the PIH, the distribution of consumption across consecutive periods is the result of an optimizing method by which each consumer tries to maximize his utility. At the same time, whatever ratio of income one devotes to consumption in each period, all these consumption expenditures are allocated in the course of


id: permanent-income-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Permanent_income_hypothesis-2.md
category: reference
title: Permanent income hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Permanent_income_hypothesis
date_saved: 2026-05-05T10:00:12.694267+00:00
instance: kb-cron
parent: permanent-income-hypothesis-20260505-0
summary:
== Empirical evidence == Observations, recorded from 1888 to 1941, of stagnant average propensity to consume in the face of rising real incomes provide strong evidence for the existence of the permanent income hypothesis. An early test of the permanent income hypothesis was reported by Robert Hall in 1978, and, assuming rational expectations, finds consumption follows a martingale sequence. Hall & Mishkin (1982) analyze data from 2,000 households and find consumption responds much more strongly to permanent than to transitory movements of income, and reinforce the compatibility of the PIH with 80% of households in the sample. Bernanke (1984) finds 'no evidence against the permanent income hypothesis' when looking at data on automobile consumption. In contrast, Flavin (1981) finds consumption is very sensitive to transitory income shocks ('excess sensitivity'), while Mankiw & Shapiro (1985) dispute these findings, arguing that Flavin's test specification (which assumes income is stationary) is biased towards finding excess sensitivity. Souleles (1999) uses income tax refunds to test the PIH. Since a refund depends on income in the previous year, it is predictable income and should thus not alter consumption in the year of its receipt. The evidence finds that consumption is sensitive to the income refund,


id: planetarium-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Planetarium_hypothesis-0.md
category: reference
title: Planetarium hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Planetarium_hypothesis
date_saved: 2026-05-05T10:00:13.935407+00:00
instance: kb-cron
parent: planetarium-hypothesis-20260505-0
summary:
The planetarium hypothesis, conceived in 2001 by Stephen Baxter, attempts to provide a solution to the Fermi paradox by holding that our astronomical observations represent an illusion, created by a Type III civilization capable of manipulating matter and energy on galactic scales. He postulates that we do not see evidence of extraterrestrial life because the universe has been engineered so that it appears empty of other life. == Background == There is no reliable or reproducible evidence that aliens have visited Earth. No transmissions or evidence of intelligent extraterrestrial life have been detected or observed anywhere other than Earth in the Universe. This runs counter to the knowledge that the Universe is filled with a very large number of planets, some of which likely hold the conditions hospitable for life. Life on Earth has shown the tendency to typically expand until it fills all available niches. These contradictory facts form the basis for the Fermi paradox, of which the planetarium hypothesis is one proposed solution. == Criticism == The hypothesis has been considered by some authors as speculative and even next to useless in any practical scientific sense and more related to the theological mode of thinking along with the


id: priority-of-the-gospel-of-marcion-20260505-0
file: data/en.wikipedia.org/wiki/Priority_of_the_Gospel_of_Marcion-0.md
category: reference
title: Priority of the Gospel of Marcion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Priority_of_the_Gospel_of_Marcion
date_saved: 2026-05-05T10:00:15.126494+00:00
instance: kb-cron
parent: priority-of-the-gospel-of-marcion-20260505-0
summary:
Marcion priority is the hypothesis that the Gospel of Marcion preceded the other gospels and is an attempted solution to the synoptic problem. This hypothesis claims that the first produced or compiled gospel was that of Marcion and that this gospel was used as inspiration for some, or all, of the canonical gospels: Matthew, Mark, Luke, and John. Matthias Klinghardt is a modern proponent of this hypothesis. The majority of scholars agree that this gospel was a later revised version of the Gospel of Luke rather than with Marcionite Priority. == Context == Marcion of Sinope (c. 85 – c. 160) is considered to be the founder of an early Christian movement called Marcionism. He is regarded by numerous scholars as having produced the first New Testament canon which included a gospel, called the Evangelion (or Euangelion), which he either acquired or significantly developed, or even fully wrote. Some have called it or even still call it the Gospel of Marcion. Some Church Fathers said that the Marcionite Evangelion was a revision of the gospel of Luke with some passages expunged from it to fit Marcion's theology; this hypothesis on the relationship between the gospels of Marcion and of Luke


id: priority-of-the-gospel-of-marcion-20260505-1
file: data/en.wikipedia.org/wiki/Priority_of_the_Gospel_of_Marcion-1.md
category: reference
title: Priority of the Gospel of Marcion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Priority_of_the_Gospel_of_Marcion
date_saved: 2026-05-05T10:00:15.126494+00:00
instance: kb-cron
parent: priority-of-the-gospel-of-marcion-20260505-0
summary:
In his 2013 book, The First New Testament: Marcion's Scriptural Canon, Jason BeDuhn said he considers that the gospel of Marcion was not produced or adapted by Marcion, but instead that the Gospel of Marcion was a preexisting gospel adopted by Marcion and his movement. He believes that: "On the whole, the differences between Luke and the Evangelion [i.e. the Gospel of Marcion] resist explanation on ideological grounds, and point instead toward Semler's original suggestion 250 years ago: the two gospels could be alternative versions adapted for primarily Jewish and primarily Gentile readers, respectively. In other words, the differences served practical, mission-related purposes rather than ideological, sectarian ones. Under such a scenario, the Evangelion would be transmitted within exactly the wing of emerging Christianity in which we can best situate Marcion’s own religious background". Semler's hypothesis being that "the Evangelion and Luke are both pre-Marcionite versions going back to a common original". In his 2014 book Marcion and the Dating of the Synoptic Gospels, Markus Vinzent proposed, based on his interpretation of aspects of Tertullian's Against Marcion (and other works of Tertullian), that the Marcionite Evangelion was first written as a document "for his classroom (without Antitheses and perhaps without


id: protein-leverage-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Protein_leverage_hypothesis-0.md
category: reference
title: Protein leverage hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Protein_leverage_hypothesis
date_saved: 2026-05-05T10:00:16.332370+00:00
instance: kb-cron
parent: protein-leverage-hypothesis-20260505-0
summary:
The protein leverage hypothesis states that human beings will prioritize the consumption of protein in food over other dietary components, and will eat until protein needs have been met, regardless of energy content, thus leading to over-consumption of foodstuffs when their protein content is low. This hypothesis has been put forward as a potential explanation of the obesity epidemic. Empirical tests have provided some evidence to confirm the hypothesis with one study suggesting that this could be a link between ultra-processed foods and the prevalence of obesity in the developed world. In the 1980s, David Raubenheimer and Stephen Simpson, researchers now at the University of Sydney, began to study appetite and food intake in locusts. By studying responses to artificial diets with differing compositions of protein and carbohydrate, they developed the protein leverage hypothesis. Their experiments showed that those who aren't getting enough protein in their diet will continue to be hungry, even when their overall caloric intake is high. "Protein decoys", such as ultraprocessed savory foods that contain little protein (e.g., barbecue chips), are likely to be attractive and to result in overeating. The hormone FGF21, which is released from the liver, can drive savory-seeking behavior under conditions of


id: proto-ionians-20260505-0
file: data/en.wikipedia.org/wiki/Proto-Ionians-0.md
category: reference
title: Proto-Ionians
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Proto-Ionians
date_saved: 2026-05-05T10:00:17.537507+00:00
instance: kb-cron
parent: proto-ionians-20260505-0
summary:
The Proto-Ionians are the hypothetical earliest speakers of the Ionic dialects of Ancient Greek, chiefly in the works of Jean Faucounau. The relation of Ionic to the other Greek dialects has been subject to some debate. It is mostly grouped with Arcadocypriot as opposed to Doric, reflecting two waves of migration into Greece following the Proto-Greek period, but sometimes also as separate from Arcadocypriot on equal footing with Doric, suggesting three distinct waves of migration. == Position of Ionic Greek == Mainstream Greek linguistics separates the Greek dialects into two large genetic groups, one including Doric Greek and the other including both Arcadocypriot and Ionic Greek. But alternative approaches proposing three groups are not uncommon; Thumb and Kieckers (1932) propose three groups, classifying Ionic as genetically just as separate from Arcadocypriot as from Doric. Like a few other linguists (Vladimir Georgiev, C. J. Rhuijgh, Pierre Lévêque, etc.), the bipartite classification is known as the "Risch–Chadwick theory", named after its two famous proponents, Ernst Risch and John Chadwick.[1] The "Proto-Ionians" first appear in the work of Ernst Curtius (1887), who believed that the Attic-Ionic dialect group was due to an "Ionicization" of Attica by immigration from Ionia in historical times. Curtius


id: proto-ionians-20260505-1
file: data/en.wikipedia.org/wiki/Proto-Ionians-1.md
category: reference
title: Proto-Ionians
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Proto-Ionians
date_saved: 2026-05-05T10:00:17.537507+00:00
instance: kb-cron
parent: proto-ionians-20260505-0
summary:
== Faucounau == The tripartite theory was revived by amateur linguist Jean Faucounau. In his view, the first Greek settlers in their historical territory were the (Pelasgic) "proto-Ionians", who were separated around 3000 BC from both the proto-Dorians and the proto-Mycenaeans. Faucounau traces this three-wave model to similar views put forward by Paul Kretschmer in the 1890s and the 1900s (i.e., before the decipherment of Linear B), with a modification: the (proto-Ionic) First wave came by sea, the "Proto-Ionians" settling first in the Cycladic Islands, then in Euboea and Attica. The last two waves are the generally accepted arrival of the Mycenaean Greeks (the linguistic predecessors of the Arcadocypriot speakers) in around 1700 BC and the Dorian invasion around 1100 BC. Following Georgiev,[4][5] Faucounau makes three arguments for the proto-Ionic language.[6] The first is the explanation of certain Mycenaean forms as loan-words from the proto-Ionians already present in Greece: he asserts that digamma is unexpectedly absent from some Mycenaean words,[7] the occasional resolution of Indo-European vocalic r to -or/ro- instead of -ar/ra-; to-pe-za for τράπεζα,[8] and the explanation of Mycenaean pa-da-yeu as Greek παδάω/πηδάω,[9] "spring leap, bound", which he interprets as both cognate with, and having the same meaning as,


id: proto-ionians-20260505-2
file: data/en.wikipedia.org/wiki/Proto-Ionians-2.md
category: reference
title: Proto-Ionians
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Proto-Ionians
date_saved: 2026-05-05T10:00:17.537507+00:00
instance: kb-cron
parent: proto-ionians-20260505-0
summary:
== References == Jean Faucounau, Le déchiffrement du Disque de Phaistos, Paris 1999. ^Jean Faucounau, Les Proto-Ioniens : histoire d'un peuple oublié, Paris 2001. Esp. pp. ^33ff, ^35ff, ^37f, ^p. 57, ^p. 61, ^p. 63 ^124. Review: Paul Faure, Revue des études grecques Vol. 15 (2002), p. 424f. Jean Faucounau, Les Peuples de la Mer et leur Histoire, Paris 2003. Jean Faucounau, Les Origines Grecques à l'Age de Bronze, Paris 2005. ^Vladimir Georgiev, "Mycénien et homérique: Le problème du digamma" in Proceedings of the Cambridge Colloquium on Mycenaean Studies, Cambridge 1966, p. 104-124. ^Vladimir Georgiev, "Le traitement des sonantes voyelles indo-européennes et le problème du caractère de la langue mycénienne" in Acta Mycenaea, Salamanca 1972, p. 361-379. ^Jonathan M. Hallm, Hellenicity: between ethnicity and culture. University of Chicago Press, 2002, ISBN 978-0-226-31329-0, p. 39. ^George Hempl, Prehistoric Wanderings of the Hittite Greeks, in Mediterranean Studies, Vol III. Stanford University Press (1931), ISBN 978-0-8047-0838-8 Paul Kretschmer, Einleitung in die Geschichte der griechischen Sprache (1896). Pierre Lévêque, L'aventure grecque, p. 16-29. ^Michael W. Ovenden, The Origin of the Constellations in The Philosophical Journal 3 (1966), p. 1-18. ^A. C. D. Crommelin "The ancient Constellation Figures" in Hutchinson's Splendour of the Heavens London,


id: racial-invariance-20260505-0
file: data/en.wikipedia.org/wiki/Racial_invariance-0.md
category: reference
title: Racial invariance
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Racial_invariance
date_saved: 2026-05-05T10:00:18.678549+00:00
instance: kb-cron
parent: racial-invariance-20260505-0
summary:
In criminology, racial invariance refers to a hypothesis that the effects of structural disadvantage on rates of violent crime are the same for all racial groups. This hypothesis is a major component of structural perspectives on the causes of crime, such as social disorganization theory and anomie. It can be traced back to William Julius Wilson's 1987 book The Truly Disadvantaged, which argued that racial differences in crime rates are due to differences in the communities in which American whites and blacks live. Since then, it has become a major component of the general theory of crime. == References ==


id: rare-earth-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-0.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
In planetary astronomy and astrobiology, the Rare Earth hypothesis argues that the origin of life and the evolution of biological complexity, such as sexually reproducing, multicellular organisms on Earth, and subsequently human intelligence, required an improbable combination of astrophysical and geological events and circumstances. According to the hypothesis, complex extraterrestrial life is an improbable phenomenon and likely to be rare throughout the universe as a whole. The term "Rare Earth" originates from Rare Earth: Why Complex Life Is Uncommon in the Universe (2000), a book by Peter Ward, a geologist and paleontologist, and Donald E. Brownlee, an astronomer and astrobiologist, both faculty members at the University of Washington. The hypothesis has been argued to be a possible solution to the Fermi paradox. In the 1970s and 1980s, Carl Sagan and Frank Drake, among others, argued that Earth is a typical rocky planet in a typical planetary system, located in a non-exceptional region of a common galaxy, now known to be a barred spiral galaxy. From the principle of mediocrity (extended from the Copernican principle), they argued that the evolution of life on Earth, including human beings, was also typical, and therefore that the universe teems with complex life. In contrast,


id: rare-earth-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-1.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
Item #1 rules out the outermost reaches of a galaxy; #2 and #3 rule out galactic inner regions. Hence a galaxy's habitable zone may be a relatively narrow ring of adequate conditions sandwiched between its uninhabitable center and outer reaches. Also, a habitable planetary system must maintain its favorable location long enough for complex life to evolve. A star with an eccentric (elliptical or hyperbolic) galactic orbit will pass through some spiral arms, unfavorable regions of high star density; thus a life-bearing star must have a galactic orbit that is nearly circular, with a close synchronization between the orbital velocity of the star and of the spiral arms. This further restricts the galactic habitable zone within a fairly narrow range of distances from the Galactic Center. Lineweaver et al. calculate this zone to be a ring 7 to 9 kiloparsecs in radius, including no more than 10% of the stars in the Milky Way, about 20 to 40 billion stars. Gonzalez et al. would halve these numbers; they estimate that at most 5% of stars in the Milky Way fall within the galactic habitable zone. Approximately 77% of observed galaxies are spiral, two-thirds of all spiral galaxies are barred, and


id: rare-earth-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-2.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
Rare Earth proponents argue that a planetary system capable of sustaining complex life must be structured more or less like the Solar System, with small, rocky inner planets and massive outer gas giants. Without the protection of such "celestial vacuum cleaner" planets, such as Jupiter, with strong gravitational pulls, other planets would be subject to more frequent catastrophic asteroid collisions. An asteroid only twice the size of the one which caused the Cretaceous–Paleogene extinction might have wiped out all complex life. Observations of exoplanets have shown that arrangements of planets similar to the Solar System are rare. Most planetary systems have super-Earths, several times larger than Earth, close to their star, whereas the Solar System's inner region has only a few small rocky planets and none inside Mercury's orbit. Only 10% of stars have giant planets similar to Jupiter and Saturn, and those few rarely have stable, nearly circular orbits distant from their star. Konstantin Batygin and colleagues argue that these features can be explained if, early in the history of the Solar System, Jupiter and Saturn drifted towards the Sun, sending showers of planetesimals towards the super-Earths which sent them spiralling into the Sun, and ferrying icy building blocks


id: rare-earth-hypothesis-20260505-3
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-3.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
The Moon is unusual because the other rocky planets in the Solar System either have no satellites (Mercury and Venus), or only relatively tiny satellites which are most likely captured asteroids (Mars). After Charon, the Moon is also the largest natural satellite in the Solar System relative to the size of its parent body, being 27% the size of Earth. The giant-impact theory hypothesizes that the Moon resulted from the impact of a roughly Mars-sized body, dubbed Theia, with the young Earth. This giant impact also gave the Earth its axial tilt (inclination) and velocity of rotation. Rapid rotation reduces the daily variation in temperature and makes photosynthesis viable. The Rare Earth hypothesis further argues that the axial tilt cannot be too large or too small (relative to the orbital plane). A planet with a large tilt will experience extreme seasonal variations in climate. A planet with little or no tilt will lack the stimulus to evolution that climate variation provides. In this view, the Earth's tilt is "just right". The gravity of a large satellite also stabilizes the planet's tilt; without this effect, the variation in tilt would be chaotic, probably making complex life forms on land impossible. If


id: rare-earth-hypothesis-20260505-4
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-4.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
== Rare Earth equation == The following discussion is adapted from Cramer. The Rare Earth equation is Ward and Brownlee's riposte to the Drake equation. It calculates N {\displaystyle N} , the number of Earth-like planets in the Milky Way having complex life forms, as: N = N ∗ ⋅ n e ⋅ f g ⋅ f p ⋅ f p m ⋅ f i ⋅ f c ⋅ f l ⋅ f m ⋅ f j ⋅ f m e {\displaystyle N=N^{*}\cdot n_{e}\cdot f_{g}\cdot f_{p}\cdot f_{pm}\cdot f_{i}\cdot f_{c}\cdot f_{l}\cdot f_{m}\cdot f_{j}\cdot f_{me}} where: N* is the number of stars in the Milky Way. This number is not well-estimated, because the Milky Way's mass is not well estimated, with little information about the number of small stars. N* is at least 100 billion, and may be as high as 500 billion, if there are many low visibility stars. n e {\displaystyle n_{e}} is the average number of planets in a star's habitable zone. This zone is fairly narrow, being constrained by the requirement that the average planetary temperature be consistent with water remaining liquid throughout the time required for complex life to evolve. Thus, n e {\displaystyle n_{e}} =1 is


id: rare-earth-hypothesis-20260505-5
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-5.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
Stuart Ross Taylor, a specialist on the Solar System, firmly believed in the hypothesis. Taylor concluded that the Solar System is probably unusual, because it resulted from so many chance factors and events. Stephen Webb, a physicist, mainly presents and rejects candidate solutions for the Fermi paradox. The Rare Earth hypothesis emerges as one of the few solutions left standing by the end of his book Where is Everybody? Simon Conway Morris, a paleontologist, endorses the Rare Earth hypothesis in chapter 5 of his Life's Solution: Inevitable Humans in a Lonely Universe, and cites Ward and Brownlee's book with approval. John D. Barrow and Frank J. Tipler, cosmologists, vigorously defend the hypothesis that humans are likely to be the only intelligent life in the Milky Way, and perhaps the entire universe. But this hypothesis is not central to their book The Anthropic Cosmological Principle, a thorough study of the anthropic principle and of how the laws of physics are peculiarly suited to enable the emergence of complexity in nature. Ray Kurzweil, a computer pioneer and self-proclaimed Singularitarian, argues in his 2005 book The Singularity Is Near that the coming Singularity requires that Earth be the first planet on which sapient,


id: rare-earth-hypothesis-20260505-6
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-6.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
Some argue that Rare Earth's estimates of rocky planets in habitable zones ( n e {\displaystyle n_{e}} in the Rare Earth equation) are too restrictive. James Kasting cites the Titius–Bode law to contend that it is a misnomer to describe habitable zones as narrow when there is a 50% chance of at least one planet orbiting within one. In 2013, astronomers using the Kepler space telescope's data estimated that about one-fifth of G-type and K-type stars (sun-like stars and orange dwarfs) are expected to have an Earth-sized or super-Earth-sized planet (1–2 Earths wide) close to an Earth-like orbit (0.25–4 F🜨), yielding about 8.8 billion of them for the entire Milky Way Galaxy. === Uncertainty over Jupiter's role === The requirement for a system to have a Jovian planet as protector (Rare Earth equation factor f j {\displaystyle f_{j}} ) has been challenged, affecting the number of proposed extinction events (Rare Earth equation factor f m e {\displaystyle f_{me}} ). Kasting's 2001 review of Rare Earth questions whether a Jupiter protector has any bearing on the incidence of complex life. Computer modelling including the 2005 Nice model and 2007 Nice 2 model yield inconclusive results in relation to Jupiter's gravitational influence


id: rare-earth-hypothesis-20260505-7
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-7.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
The hypothesis that molecular oxygen, necessary for animal life, is rare and that a Great Oxygenation Event (Rare Earth equation factor f c {\displaystyle f_{c}} ) could only have been triggered and sustained by tectonics, appears to have been invalidated by more recent discoveries. Ward and Brownlee ask "whether oxygenation, and hence the rise of animals, would ever have occurred on a world where there were no continents to erode". Extraterrestrial free oxygen has recently been detected around other solid objects, including Mercury, Venus, Mars, Jupiter's four Galilean moons, Saturn's moons Enceladus, Dione and Rhea and even the atmosphere of a comet. This has led scientists to speculate whether processes other than photosynthesis could be capable of generating an environment rich in free oxygen. Wordsworth (2014) concludes that oxygen generated other than through photodissociation may be likely on Earth-like exoplanets, and could actually lead to false positive detections of life. Narita (2015) suggests photocatalysis by titanium dioxide as a geochemical mechanism for producing oxygen atmospheres. Since Ward & Brownlee's assertion that "there is irrefutable evidence that oxygen is a necessary ingredient for animal life", anaerobic metazoa have been found that indeed do metabolise without oxygen. Spinoloricus cinziae, for example, a


id: rare-earth-hypothesis-20260505-8
file: data/en.wikipedia.org/wiki/Rare_Earth_hypothesis-8.md
category: reference
title: Rare Earth hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
date_saved: 2026-05-05T10:00:19.880934+00:00
instance: kb-cron
parent: rare-earth-hypothesis-20260505-0
summary:
The assertion that the Moon's stabilization of Earth's obliquity and spin is a requirement for complex life has been questioned. Kasting argues that a moonless Earth would still possess habitats with climates suitable for complex life and questions whether the spin rate of a moonless Earth can be predicted. Although the giant impact theory posits that the impact forming the Moon increased Earth's rotational speed to make a day about 5 hours long, the Moon has slowly "stolen" much of this speed to reduce Earth's solar day since then to about 24 hours and continues to do so: in 100 million years Earth's solar day will be roughly 24 hours 38 minutes (the same as Mars's solar day); in 1 billion years, 30 hours 23 minutes. Larger secondary bodies would exert proportionally larger tidal forces that would in turn decelerate their primaries faster and potentially increase the solar day of a planet in all other respects like Earth to over 120 hours within a few billion years. This long solar day would make effective heat dissipation for organisms in the tropics and subtropics extremely difficult in a similar manner to tidal locking to a red dwarf star. Short days (high


id: relative-income-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Relative_income_hypothesis-0.md
category: reference
title: Relative income hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Relative_income_hypothesis
date_saved: 2026-05-05T10:00:21.052401+00:00
instance: kb-cron
parent: relative-income-hypothesis-20260505-0
summary:
The relative income hypothesis was developed by James Duesenberry in 1949. It consists of two separate consumption hypothesis. The first hypothesis states that an individual's attitude to consumption is dictated more by their income in relation to others than by an abstract standard of living. The percentage of income consumed by an individual depends on their percentile position within the income distribution. The second hypothesis states that the present consumption is influenced not merely by present levels of absolute and relative income but also by levels of consumption attained in a previous period. In Duesenberry's opinion, it is difficult for a family to reduce a level of consumption once it is attained. The aggregate ratio of consumption to income is assumed to depend on the level of present income relative to past peak income. == Sources == Duesenberry, J. S. Income, Saving and the Theory of Consumer Behaviour. Cambridge: Harvard University Press, 1949.[1] Frank, Robert H., 2005. “The Mysterious Disappearance of James Duesenberry,” The New York Times, June 9, 2005. Hollander, Heinz, 2001. “On the validity of utility statements: standard theory versus Duesenberry’s,” Journal of economic Behavior & Organization 45, 3: 227–249. McCormick, Ken (2018). "James Duesenberry as a practitioner


id: riemann-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-0.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
In mathematics, the Riemann hypothesis is the conjecture that the Riemann zeta function has its zeros only at the negative even integers and complex numbers with real part ⁠1/2⁠. Many consider it to be the most important unsolved problem in pure mathematics. It is of great interest in number theory because it implies results about the distribution of prime numbers. It was proposed by Bernhard Riemann, after whom it is named. According to a 2026 survey, there is overwhelming numerical evidence for the hypothesis, but no proof is known. The Riemann hypothesis and some of its generalizations, along with Goldbach's conjecture and the twin prime conjecture, make up Hilbert's eighth problem in David Hilbert's list of twenty-three unsolved problems; it is also one of the Millennium Prize Problems of the Clay Mathematics Institute, which offers US$1 million for a solution to any of them. The name is also used for some closely related analogues, some of which have been proved, such as the Riemann hypothesis for curves over finite fields, which was proved by André Weil. The Riemann zeta function ζ {\displaystyle \zeta } is a function whose argument may be any complex number other than 1, and whose values


id: riemann-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-1.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
One may then define ζ ( s ) {\displaystyle \zeta (s)} for all remaining nonzero complex numbers s {\displaystyle s} ( Re ⁡ ( s ) ≤ 0 {\displaystyle \operatorname {Re} (s)\leq 0} and s ≠ 0 {\displaystyle s\neq 0} ) by applying this equation outside the strip, and letting ζ ( s ) {\displaystyle \zeta (s)} equal the right side of the equation whenever s {\displaystyle s} has non-positive real part (and s ≠ 0 {\displaystyle s\neq 0} ). If s {\displaystyle s} is a negative even integer, then ζ ( s ) = 0 {\displaystyle \zeta (s)=0} , because the factor sin ⁡ ( π s / 2 ) {\displaystyle \sin(\pi s/2)} vanishes; these are the zeta function's trivial zeros. (If s {\displaystyle s} is a positive even integer this argument does not apply because the zeros of the sine function are canceled by the poles of the gamma function as it takes negative integer arguments.) The value ζ(0) = −1/2 is not determined by the functional equation, but is the limiting value of ζ ( s ) {\displaystyle \zeta (s)} as s {\displaystyle s} approaches zero. The functional equation also implies that the zeta function has no


id: riemann-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-2.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
The terms li ⁡ ( x ρ ) {\displaystyle \operatorname {li} (x^{\rho })} involving the zeros of the zeta function need some care in their definition as li {\displaystyle \operatorname {li} } has branch points at 0 and 1, and are defined (for x > 1 {\displaystyle x>1} ) by analytic continuation in the complex variable ρ {\displaystyle \rho } in the region Re ⁡ ( ρ ) > 0 {\displaystyle \operatorname {Re} (\rho )>0} ; i.e., they should be considered as Ei(ρ log x). The other terms also correspond to zeros: the dominant term li ⁡ ( x ) {\displaystyle \operatorname {li} (x)} comes from the pole at s = 1 {\displaystyle s=1} , considered as a zero of multiplicity − 1 {\displaystyle -1} , and the remaining small terms come from the trivial zeros. For some graphs of the sums of the first few terms of this series see Riesel & Göhl (1970) or Zagier (1977). This formula says that the zeros of the Riemann zeta function control the oscillations of primes around their "expected" positions. Riemann knew that the non-trivial zeros of the zeta function were symmetrically distributed about the line s = 1 / 2 +


id: riemann-hypothesis-20260505-3
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-3.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
The Riemann hypothesis puts a rather tight bound on the growth of M, since Odlyzko & te Riele (1985) disproved the slightly stronger Mertens conjecture | M ( x ) | ≤ x . {\displaystyle |M(x)|\leq {\sqrt {x}}.} Another closely related result is due to Björner (2011), that the Riemann hypothesis is equivalent to the statement that the Euler characteristic of the simplicial complex determined by the lattice of integers under divisibility is o ( n 1 / 2 + ϵ ) {\displaystyle o(n^{1/2+\epsilon })} for all ϵ > 0 {\displaystyle \epsilon >0} (see incidence algebra). The Riemann hypothesis is equivalent to many other conjectures about the rate of growth of other arithmetic functions aside from μ(n). A typical example is Robin's theorem, which states that if σ(n) is the sigma function, given by σ ( n ) = ∑ d ∣ n d {\displaystyle \sigma (n)=\sum _{d\mid n}d} then σ ( n ) < e γ n log ⁡ log ⁡ n {\displaystyle \sigma (n)<e^{\gamma }n\log \log n} for all n > 5040 if and only if the Riemann hypothesis is true, where γ is the Euler–Mascheroni constant. A related bound was given by Jeffrey Lagarias in 2002, who


id: riemann-hypothesis-20260505-4
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-4.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
f ( x ) = ∑ ν = 1 n c ν ρ ( θ ν x ) {\displaystyle f(x)=\sum _{\nu =1}^{n}c_{\nu }\rho \left({\frac {\theta _{\nu }}{x}}\right)} where ρ(z) is the fractional part of z, 0 ≤ θν ≤ 1, and ∑ ν = 1 n c ν θ ν = 0 , {\displaystyle \sum _{\nu =1}^{n}c_{\nu }\theta _{\nu }=0,} is dense in the Hilbert space L2(0,1) of square-integrable functions on the unit interval. Beurling (1955) extended this by showing that the zeta function has no zeros with real part greater than 1/p if and only if this function space is dense in Lp(0,1). This Nyman-Beurling criterion was strengthened by Baez-Duarte to the case where θ ν ∈ { 1 / k } k ≥ 1 {\displaystyle \theta _{\nu }\in \{1/k\}_{k\geq 1}} . Salem (1953) showed that the Riemann hypothesis is true if and only if the integral equation ∫ 0 ∞ z − σ − 1 φ ( z ) e x / z + 1 d z = 0 {\displaystyle \int _{0}^{\infty }{\frac {z^{-\sigma -1}\varphi (z)}{{e^{x/z}}+1}}\,dz=0} has no non-trivial bounded solutions φ {\displaystyle \varphi } for 1 / 2 < σ < 1 {\displaystyle 1/2<\sigma <1} . Weil's


id: riemann-hypothesis-20260505-5
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-5.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
In 1913, Grönwall showed that the generalized Riemann hypothesis implies that Gauss's list of imaginary quadratic fields with class number 1 is complete, though Baker, Stark and Heegner later gave unconditional proofs of this without using the generalized Riemann hypothesis. In 1917, Hardy and Littlewood showed that the generalized Riemann hypothesis implies a conjecture of Chebyshev that lim x → 1 − ∑ p > 2 ( − 1 ) ( p + 1 ) / 2 x p = + ∞ , {\displaystyle \lim _{x\to 1^{-}}\sum _{p>2}(-1)^{(p+1)/2}x^{p}=+\infty ,} which says that primes 3 mod 4 are more common than primes 1 mod 4 in some sense. (For related results, see Prime number theorem § Prime number race.) In 1923, Hardy and Littlewood showed that the generalized Riemann hypothesis implies a weak form of the Goldbach conjecture for odd numbers: that every sufficiently large odd number is the sum of three primes, though in 1937 Vinogradov gave an unconditional proof. In 1997 Deshouillers, Effinger, te Riele, and Zinoviev showed that the generalized Riemann hypothesis implies that every odd number greater than 5 is the sum of three primes. In 2013 Harald Helfgott proved the ternary Goldbach conjecture without the GRH


id: riemann-hypothesis-20260505-6
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-6.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
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for infinitely many n, where φ(n) is Euler's totient function and γ is Euler's constant. Ribenboim remarks that: "The method of proof is interesting, in that the inequality is shown first under the assumption that the Riemann hypothesis is true, secondly under the contrary assumption." == Generalizations and analogs == === Dirichlet L-series and other number fields === The Riemann hypothesis can be generalized by replacing the Riemann zeta function by the formally similar, but much more general, global L-functions. In this broader setting, one expects the non-trivial zeros of the global L-functions to have real part 1/2. It is these conjectures, rather than the classical Riemann hypothesis only for the single Riemann zeta function, which account for the true importance of the Riemann hypothesis in mathematics. The most common generalized Riemann hypothesis extends the Riemann hypothesis to all Dirichlet L-functions. In particular it implies the conjecture that Siegel zeros (zeros of L-functions between 1/2 and 1) do not exist. The extended Riemann hypothesis extends the Riemann hypothesis to all Dedekind zeta functions of algebraic number fields. Since Dedekind zeta function for abelian extension of the rationals can be expressed as product of Dirichlet L-functions and only possible pole is


id: riemann-hypothesis-20260505-7
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-7.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
=== Montgomery's pair correlation conjecture === Montgomery (1973) suggested the pair correlation conjecture that the correlation functions of the (suitably normalized) zeros of the zeta function should be the same as those of the eigenvalues of a random hermitian matrix. Odlyzko (1987) showed that this is supported by large-scale numerical calculations of these correlation functions. Montgomery showed that (assuming the Riemann hypothesis) at least 2/3 of all zeros are simple, and a related conjecture is that all zeros of the zeta function are simple (or more generally have no non-trivial integer linear relations between their imaginary parts). Dedekind zeta functions of algebraic number fields, which generalize the Riemann zeta function, often do have multiple complex zeros. This is because the Dedekind zeta functions factorize as a product of powers of Artin L-functions, so zeros of Artin L-functions sometimes give rise to multiple zeros of Dedekind zeta functions. Other examples of zeta functions with multiple zeros are the L-functions of some elliptic curves: these can have multiple zeros at the real point of their critical line; the Birch-Swinnerton-Dyer conjecture predicts that the multiplicity of this zero is the rank of the elliptic curve. === Other zeta functions === There are many


id: riemann-hypothesis-20260505-8
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-8.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
=== Lee–Yang theorem === The Lee–Yang theorem states that the zeros of certain partition functions in statistical mechanics all lie on a "critical line" with their real part equal to 0, and this has led to some speculation about a relationship with the Riemann hypothesis. === Turán's result === Pál Turán showed that if the functions ∑ n = 1 N n − s {\displaystyle \sum _{n=1}^{N}n^{-s}} have no zeros when the real part of s is greater than one then T ( x ) = ∑ n ≤ x λ ( n ) n ≥ 0 for x > 0 , {\displaystyle T(x)=\sum _{n\leq x}{\frac {\lambda (n)}{n}}\geq 0{\text{ for }}x>0,} where λ(n) is the Liouville function given by (−1)r if n has r prime factors. He showed that this in turn would imply that the Riemann hypothesis is true. But Haselgrove (1958) proved that T(x) is negative for infinitely many x (and also disproved the closely related Pólya conjecture), and Borwein, Ferguson & Mossinghoff (2008) showed that the smallest such x is 72185376951205. Spira (1968) showed by numerical calculation that the finite Dirichlet series above for N = 19 has a zero with real part greater than 1. Turán


id: riemann-hypothesis-20260505-9
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-9.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
S ( T ) = 1 π A r g ⁡ ( ζ ( 1 / 2 + i T ) ) = O ( log ⁡ T ) . {\displaystyle S(T)={\frac {1}{\pi }}\mathop {\mathrm {Arg} } (\zeta (1/2+iT))=O(\log T).} So the density of zeros with imaginary part near T is about log(T)/(2π), and the function S describes the small deviations from this. The function S(t) jumps by 1 at each zero of the zeta function, and for t ≥ 8 it decreases monotonically between zeros with derivative close to −log t. Trudgian (2014) proved that, if T > e, then | N ( T ) − T 2 π log ⁡ T 2 π e | ≤ 0.112 log ⁡ T + 0.278 log ⁡ log ⁡ T + 3.385 + 0.2 T {\displaystyle |N(T)-{\frac {T}{2\pi }}\log {\frac {T}{2\pi e}}|\leq 0.112\log T+0.278\log \log T+3.385+{\frac {0.2}{T}}} . Karatsuba (1996) proved that every interval (T, T + H] for H ≥ T 27 82 + ε {\displaystyle H\geq T^{{\frac {27}{82}}+\varepsilon }} contains at least H ( log ⁡ T ) 1 3 e − c log ⁡ log ⁡ T {\displaystyle H(\log T)^{\frac {1}{3}}e^{-c{\sqrt {\log \log T}}}} points where the function


id: riemann-hypothesis-20260505-10
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-10.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
=== Zero-free regions === The most extensive computer search by Platt and Trudgian for counterexamples of the Riemann hypothesis has verified it for |t| ≤ 3.0001753328×1012. Beyond that zero-free regions are known as inequalities concerning σ + i t, which can be zeroes. The oldest version is from De la Vallée-Poussin (1899–1900), who proved there is a region without zeroes that satisfies 1 − σ ≥ ⁠C/log(t)⁠ for some positive constant C. In other words, zeros cannot be too close to the line σ = 1: there is a zero-free region close to this line. This has been enlarged by several authors using methods such as Vinogradov's mean-value theorem. The most recent paper by Mossinghoff, Trudgian and Yang is from December 2022 and provides four zero-free regions that improved the previous results of Kevin Ford from 2002, Mossinghoff and Trudgian themselves from 2015 and Pace Nielsen's slight improvement of Ford from October 2022: σ ≥ 1 − 1 5.558691 log ⁡ | t | {\displaystyle \sigma \geq 1-{\frac {1}{5.558691\log |t|}}} whenever | t | ≥ 2 {\displaystyle |t|\geq 2} , σ ≥ 1 − 1 55.241 ( log ⁡ | t | ) 2 / 3 ( log ⁡ log


id: riemann-hypothesis-20260505-11
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-11.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
For any ε > 0 {\displaystyle \varepsilon >0} there exists a lower bound T 0 = T 0 ( ε ) > 0 {\displaystyle T_{0}=T_{0}(\varepsilon )>0} such that for T ≥ T 0 {\displaystyle T\geq T_{0}} and H = T 1 4 + ε {\displaystyle H=T^{{\tfrac {1}{4}}+\varepsilon }} the interval ( T , T + H ] {\displaystyle (T,T+H]} contains a zero of odd order of the function ζ ( 1 2 + i t ) {\displaystyle \zeta {\bigl (}{\tfrac {1}{2}}+it{\bigr )}} . Let N ( T ) {\displaystyle N(T)} be the total number of real zeros, and N 0 ( T ) {\displaystyle N_{0}(T)} be the total number of zeros of odd order of the function ζ ( 1 2 + i t ) {\displaystyle ~\zeta \left({\tfrac {1}{2}}+it\right)~} lying on the interval ( 0 , T ] {\displaystyle (0,T]~} . For any ε > 0 {\displaystyle \varepsilon >0} there exists T 0 = T 0 ( ε ) > 0 {\displaystyle T_{0}=T_{0}(\varepsilon )>0} and some c = c ( ε ) > 0 {\displaystyle c=c(\varepsilon )>0} , such that for T ≥ T 0 {\displaystyle T\geq T_{0}} and H = T 1 2 + ε {\displaystyle H=T^{{\tfrac {1}{2}}+\varepsilon }}


id: riemann-hypothesis-20260505-12
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-12.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
where T {\displaystyle T} is the largest known value such that the Riemann hypothesis is true for all zeros ρ {\displaystyle \rho } with ℑ ( ρ ) ∈ ( 0 , T ] {\displaystyle \Im {\left(\rho \right)}\in \left(0,T\right]} . Some calculations of zeros of the zeta function are listed below, where the "height" of a zero is the magnitude of its imaginary part, and the height of the nth zero is denoted by γn. So far all zeros that have been checked are on the critical line and are simple. (A multiple zero would cause problems for the zero finding algorithms, which depend on finding sign changes between zeros.) For tables of the zeros, see Haselgrove & Miller (1960) or Odlyzko. === Gram points === A Gram point is a point on the critical line 1/2 + it where the zeta function is real and non-zero. Using the expression for the zeta function on the critical line, ζ(1/2 + it) = Z(t)e−iθ(t), where Hardy's function, Z, is real for real t, and θ is the Riemann–Siegel theta function, we see that zeta is real when sin(θ(t)) = 0. This implies that θ(t) is an integer multiple of π, which


id: riemann-hypothesis-20260505-13
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-13.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
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parent: riemann-hypothesis-20260505-0
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=== Random matrix theory and quantum chaos === Assuming the Riemann hypothesis one can ask what further regularities might govern the distribution of the zeros of the zeta function on the critical line. One conjectural picture is that the critical zeros of the zeta function behave statistically like the eigenvalues of large random Hermitian matrices. The idea began with Hugh Montgomery's work on the pair correlation conjecture for the zeros of the zeta function. After a suitable rescaling to account for the increasing density of zeros with height, the conjectured pair correlation function agrees with that of eigenvalues in the Gaussian unitary ensemble (GUE) in random matrix theory. The connection was tested numerically by Andrew Odlyzko, who found that the spacing statistics of zeros high on the critical line agree closely with the predictions of GUE random matrix theory. The agreement extends beyond nearest-neighbor spacings to higher correlation functions, and is widely regarded as strong evidence that the zeros are modeled by the same local statistics as random matrices. The random matrix analogy is also related to the Hilbert–Pólya conjecture, and to ideas from quantum chaos. In quantum chaotic systems, eigenvalues often obey random matrix statistics, so the appearance of


id: riemann-hypothesis-20260505-14
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-14.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
instance: kb-cron
parent: riemann-hypothesis-20260505-0
summary:
Several analogues of the Riemann hypothesis have already been proved. The proof of the Riemann hypothesis for varieties over finite fields by Deligne (1974) is possibly the single strongest theoretical reason in favor of the Riemann hypothesis. This provides some evidence for the more general conjecture that all zeta functions associated with automorphic forms satisfy a Riemann hypothesis, which includes the classical Riemann hypothesis as a special case. Similarly Selberg zeta functions satisfy the analogue of the Riemann hypothesis, and are in some ways similar to the Riemann zeta function, having a functional equation and an infinite product expansion analogous to the Euler product expansion. But there are also some major differences; for example, they are not given by Dirichlet series. The Riemann hypothesis for the Goss zeta function was proved by Sheats (1998). In contrast to these positive examples, some Epstein zeta functions do not satisfy the Riemann hypothesis even though they have an infinite number of zeros on the critical line. These functions are quite similar to the Riemann zeta function, and have a Dirichlet series expansion and a functional equation, but the ones known to fail the Riemann hypothesis do not have an Euler product and are


id: riemann-hypothesis-20260505-15
file: data/en.wikipedia.org/wiki/Riemann_hypothesis-15.md
category: reference
title: Riemann hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Riemann_hypothesis
date_saved: 2026-05-05T10:00:22.283607+00:00
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parent: riemann-hypothesis-20260505-0
summary:
American Institute of Mathematics, Riemann hypothesis Zeroes database, 103 800 788 359 zeroes Apostol, Tom, Where are the zeros of zeta of s? Poem about the Riemann hypothesis, sung by John Derbyshire. Borwein, Peter, The Riemann Hypothesis (PDF), archived from the original (PDF) on 2009-03-27 (Slides for a lecture) Conrad, K. (2010), Consequences of the Riemann hypothesis Conrey, J. Brian; Farmer, David W, Equivalences to the Riemann hypothesis, archived from the original on 2010-03-16 Gourdon, Xavier; Sebah, Pascal (2004), Computation of zeros of the Zeta function (Reviews the GUE hypothesis, provides an extensive bibliography as well). Odlyzko, Andrew, Home page including papers on the zeros of the zeta function and tables of the zeros of the zeta function Odlyzko, Andrew (2002), Zeros of the Riemann zeta function: Conjectures and computations (PDF) Slides of a talk Pegg, Ed (2004), Ten Trillion Zeta Zeros, Math Games website, archived from the original on 2004-11-02, retrieved 2004-10-20. A discussion of Xavier Gourdon's calculation of the first ten trillion non-trivial zeros Rubinstein, Michael, algorithm for generating the zeros, archived from the original on 2007-04-27. du Sautoy, Marcus (2006), Prime Numbers Get Hitched, Seed Magazine, archived from the original on 2017-09-22, retrieved 2006-03-27 Watkins, Matthew R.


id: roe-effect-20260505-0
file: data/en.wikipedia.org/wiki/Roe_effect-0.md
category: reference
title: Roe effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Roe_effect
date_saved: 2026-05-05T10:00:23.501870+00:00
instance: kb-cron
parent: roe-effect-20260505-0
summary:
The Roe effect is a hypothesis about the long-term effect of abortion on the political balance of the United States, which suggests that since supporters of the legalization of abortion cause the erosion of their own political base, the practice of abortion will eventually lead to the restriction or illegalization of abortion. It is named after Roe v. Wade, the U.S. Supreme Court case that effectively legalized abortion nationwide in the U.S. Its best-known proponent is James Taranto of The Wall Street Journal who coined the phrase "Roe effect" in Best of the Web Today, his OpinionJournal.com column. Put simply, this hypothesis holds that: Those who favor legal abortion are much more likely to have the procedure than those who oppose it. Children usually follow their parents' political leanings. Therefore, pro-abortion rights parents will have more abortions and, hence, fewer children. Therefore, the pro-abortion rights population gradually shrinks in proportion to the anti-abortion population. Therefore, support for legal abortions will decline over time. A similar argument suggests that political groups that oppose abortion will tend to have more supporters in the long run than those who support it. In 2005, the Wall Street Journal published a detailed explanation and statistical


id: saxe-goldstein-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis-0.md
category: reference
title: Saxe–Goldstein hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis
date_saved: 2026-05-05T10:00:24.686477+00:00
instance: kb-cron
parent: saxe-goldstein-hypothesis-20260505-0
summary:
In archaeology, the Saxe–Goldstein hypothesis is a prediction about the relationship between a society's funerary practices and its social organization. It predicts a correlation between two phenomena: the use of specific areas to dispose of the dead, and the legitimation of control over restricted resources through claims of descent from dead ancestors. The hypothesis was first formulated by the American anthropologist Arthur Saxe in 1970, as the last in a series of eight, and was refined by Lynne Goldstein later in the 1970s. In reference to its origin, it is sometimes known as Hypothesis Eight. Saxe's work drew on the ethnographic work of Mervyn Meggitt and the role theory developed by Ward Goodenough. He predicted that, if a society contained groups of people with a shared identity (known as "corporate groups") that legitimized their claims to important, restricted resources by claiming ties to ancestors, that society would be more likely to use formal areas, such as cemeteries, for the disposal of the dead. Conversely, societies using such areas would be more likely to contain such corporate groups. His work coincided with that of Lewis Binford, who argued that funerary practices provided useful evidence for social organization and for the status


id: saxe-goldstein-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis-1.md
category: reference
title: Saxe–Goldstein hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis
date_saved: 2026-05-05T10:00:24.686477+00:00
instance: kb-cron
parent: saxe-goldstein-hypothesis-20260505-0
summary:
To the degree that corporate group rights to use and/or control crucial but restricted resources are attained and/or legitimized by means of lineal descent from the dead (i.e. lineal ties to ancestors), such groups will maintain formal disposal areas for the exclusive disposal of their dead, and conversely. Saxe considered the hypothesis supported by the cases he studied – the Kapauku, Asante, and Bontoc peoples, respectively of Central Papua, Ghana, and Luzon – but to require further testing on a larger sample. As applied to past societies, the hypothesis is an example of middle-range theory, in that it attempts to draw general conclusions about the relationship between the archaeological record and the people who produced it. It is within the tradition of processual archaeology, a movement begun in the 1960s which aimed to model archaeology on the scientific method of the natural sciences. Processual archaeology emphasized the development and testing of hypotheses about general laws of human behavior. In this respect, it was part of the larger positivist school of thought, in which knowledge is considered to be based upon observable ("empirical") facts, which can themselves be predicted from consistent rules, laws and patterns. The belief that an individual's treatment


id: saxe-goldstein-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis-2.md
category: reference
title: Saxe–Goldstein hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis
date_saved: 2026-05-05T10:00:24.686477+00:00
instance: kb-cron
parent: saxe-goldstein-hypothesis-20260505-0
summary:
In collaboration with L. P. Gall, Saxe studied itinerant swidden farmers in Malaysia who had been forced to move into permanent villages. In a 1977 publication of this study, Saxe and Gall noted that these farmers subsequently shifted toward burying their dead in formal cemeteries, and took this as evidence for Hypothesis Eight. Robert Chapman, in 1981, argued that the Saxe–Goldstein hypothesis could be used to explain the distribution of megalithic tombs in prehistoric Europe. In 1982, Maurice Bloch made a study of the Merina people of Madagascar, for whom he concluded that "the notion of ancestral land, that is land belonging to the deme [community], is totally merged with the notion of ancestors. The ancestors had lived and were buried in the ancestral land; the land, in the form of terraces, had been made by the ancestors". The anthropologist James A. Brown considers this reinforcing evidence for the Saxe–Goldstein hypothesis. In 1981, Brown described the methods of Saxe and Binford as a means of applying to material culture the social theories of Morton Fried and Elman Service, who studied the development and evolution of socio-political organization. In 1984, Jack Glazier made a study of the Mbeere people of Kenya,


id: saxe-goldstein-hypothesis-20260505-3
file: data/en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis-3.md
category: reference
title: Saxe–Goldstein hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis
date_saved: 2026-05-05T10:00:24.686477+00:00
instance: kb-cron
parent: saxe-goldstein-hypothesis-20260505-0
summary:
The Saxe–Goldstein hypothesis was criticized by post-processual archaeologists of the 1980s, who argued that it did not leave sufficient room for the beliefs and intentions of those who lived in the past and created the archaeological record. Ian Hodder, in 1982, used the example of the Mesakin people of Sudan to argue that the burial record may only represent an idealized fraction of the social relations within a society, drawing attention to what he called "the disjunction between burial pattern and social pattern". In the same year, Hodder's students Michael Shanks and Christopher Tilley criticized the functionalist position adopted by Saxe and other processualists, by which social phenomena are analyzed primarily in terms of their observable outcomes. Shanks and Tilley wrote that such arguments were inadequate to explain the specific content and context of funerary ritual, and that mortuary practices may be used to invert and misrepresent the social order as much as they may reflect it. Mike Parker Pearson, another of Hodder's students, later wrote that "to reduce the significance of ancestors and tombs to a means of subsistence management is to relegate human aspiration and motivation to wondering where the next meal is coming from". Attempts to use


id: saxe-goldstein-hypothesis-20260505-4
file: data/en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis-4.md
category: reference
title: Saxe–Goldstein hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Saxe–Goldstein_hypothesis
date_saved: 2026-05-05T10:00:24.686477+00:00
instance: kb-cron
parent: saxe-goldstein-hypothesis-20260505-0
summary:
=== Legacy === Some post-processual archaeologists returned to using funerary evidence to infer social hierarchies in the 1990s. However, during this period, funerary archaeology played a comparatively small role in archaeology, particularly in the United States, due both to cultural changes among archaeologists and to methodological difficulties with its study. The Saxe–Goldstein hypothesis remained fairly rarely used, particularly among British archaeologists. Parker Pearson wrote in 1999 that the hypothesis could partially explain why cemeteries may be constructed, but did not explain why a society would choose to adopt cemeteries rather than other means of highlighting individuals' descent from certain ancestors. He also argued that the hypothesis did not encompass the full significance of relationships between the living and the ancestors. In 2010, Emma Elder wrote that it was "in the graveyard of disused theoretical tools", though she considered that it could still be useful if applied with proper qualification. In 2013, David Edwards wrote that the Saxe–Goldstein hypothesis could be applied to certain African burial rites, such as the below-house burial practiced in West Africa, though these rituals also contained other meanings and alternative methods could be used alongside them to assert territorial claims. Hypothesis Eight was described by Chapman


id: scientific-wild-ass-guess-20260505-0
file: data/en.wikipedia.org/wiki/Scientific_wild-ass_guess-0.md
category: reference
title: Scientific wild-ass guess
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Scientific_wild-ass_guess
date_saved: 2026-05-05T10:00:25.888993+00:00
instance: kb-cron
parent: scientific-wild-ass-guess-20260505-0
summary:
Scientific wild-ass guess (SWAG) is an American English slang term meaning a rough estimate made by an expert in the field, based on experience and intuition. It is similar to the slang word guesstimate, a portmanteau of guess and estimate. == History == The slang term "SWAG" is generally thought to have originated in the US military, either the Army or the Air Force. Journalist Melvin J. Lasky wrote that it was first used casually by US Army General William Westmoreland during the Vietnam War. Westmoreland would sometimes reply "SWAG" to reporters' questions about American failure to neutralize the enemy. Westmoreland's use of the term was affirmed in court by Colonel John Frank Stewart in November 1984 during witness testimony for the lawsuit initiated by Westmoreland against CBS for their TV documentary The Uncounted Enemy: A Vietnam Deception. On the witness stand, Stewart explained that in Vietnam, the military intelligence branch that he commanded would deliver numbers of enemy strength to Westmoreland, the numbers derived from "the SWAG principle". There was laughter in the court when Stewart explained what was meant by the acronym SWAG. An earlier use of term is mentioned by linguist J. Robert Dumouchel who wrote the


id: second-continuum-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Second_continuum_hypothesis-0.md
category: reference
title: Second continuum hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Second_continuum_hypothesis
date_saved: 2026-05-05T10:00:27.020733+00:00
instance: kb-cron
parent: second-continuum-hypothesis-20260505-0
summary:
The second continuum hypothesis, also called Luzin's hypothesis or Luzin's second continuum hypothesis, is the hypothesis that 2 ℵ 0 = 2 ℵ 1 {\displaystyle 2^{\aleph _{0}}=2^{\aleph _{1}}} . It is the negation of a weakened form, 2 ℵ 0 < 2 ℵ 1 {\displaystyle 2^{\aleph _{0}}<2^{\aleph _{1}}} , of the Continuum Hypothesis (CH). It was discussed by Nikolai Luzin in 1935, although he did not claim to be the first to postulate it. The statement 2 ℵ 0 < 2 ℵ 1 {\displaystyle 2^{\aleph _{0}}<2^{\aleph _{1}}} may also be called Luzin's hypothesis. The second continuum hypothesis is independent of Zermelo–Fraenkel set theory with the Axiom of Choice (ZFC): its truth is consistent with ZFC since it is true in Cohen's model of ZFC with the negation of the Continuum Hypothesis; its falsity is also consistent since it is contradicted by the Continuum Hypothesis, which follows from V=L. It is implied by Martin's Axiom together with the negation of the CH. == Notes == == References ==


id: silurian-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Silurian_hypothesis-0.md
category: reference
title: Silurian hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Silurian_hypothesis
date_saved: 2026-05-05T10:00:28.226332+00:00
instance: kb-cron
parent: silurian-hypothesis-20260505-0
summary:
The Silurian hypothesis is a thought experiment which assesses modern science's ability to detect evidence of a prior advanced civilization, perhaps several million years ago. The most probable clues for such a civilization could be carbon, radioactive elements or temperature variation. The name "Silurian" derives from the eponymous sapient species from the BBC science fiction series Doctor Who, who in the series established an advanced civilization prior to humanity. Astrophysicist Adam Frank and climate scientist Gavin Schmidt proposed the "Silurian Hypothesis" in a 2018 paper exploring the possibility of detecting an advanced civilization before humans in the geological record. They argued that there has been sufficient fossil carbon to fuel an industrial civilization since the Carboniferous Period (~350 million years ago); however, finding direct evidence, such as technological artifacts, is unlikely due to the rarity of fossilization and Earth's exposed surface. Instead, researchers might find indirect evidence, such as climate changes, anomalies in sediment, or traces of nuclear waste. The hypothesis also speculates that artifacts from past civilizations could be found on the Moon and Mars, where erosion and tectonic activity are less likely to erase evidence. The concept of pre-human civilizations has been explored in popular culture, including novels,


id: simulation-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Simulation_hypothesis-0.md
category: reference
title: Simulation hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simulation_hypothesis
date_saved: 2026-05-05T10:00:29.485787+00:00
instance: kb-cron
parent: simulation-hypothesis-20260505-0
summary:
The simulation hypothesis proposes that what one experiences as the real world is actually a simulated reality, such as a computer simulation in which humans are constructs. There has been much debate over this topic in the philosophical discourse. Precursors include Zhuangzi's "Butterfly Dream" and René Descartes's "evil demon". In 2003, philosopher Nick Bostrom proposed the simulation argument suggesting that if a civilization becomes capable of creating conscious simulations, it could generate so many simulated beings that a randomly chosen conscious entity would almost certainly be in a simulation. This argument presents a trilemma: either such simulations are not created because of technological limitations or self-destruction; advanced civilizations choose not to create them; if advanced civilizations do create them, the number of simulations would far exceed base reality and we would therefore almost certainly be living in one. This assumes that consciousness is not uniquely tied to biological brains but can arise from any system that implements the right computational structures and processes. Variations on the idea have also been featured in science fiction, appearing as a central plot device in many stories and films, such as Simulacron-3 (1964) and The Matrix (1999). == Origins == Human history is full


id: simulation-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Simulation_hypothesis-1.md
category: reference
title: Simulation hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simulation_hypothesis
date_saved: 2026-05-05T10:00:29.485787+00:00
instance: kb-cron
parent: simulation-hypothesis-20260505-0
summary:
"The fraction of human-level civilizations that reach a posthuman stage (that is, one capable of running high-fidelity ancestor simulations) is very close to zero", or "The fraction of posthuman civilizations that are interested in running simulations of their evolutionary history, or variations thereof, is very close to zero", or "The fraction of all people with our kind of experiences that are living in a simulation is very close to one". The trilemma points out that a technologically mature "posthuman" civilization would have enormous computing power. If even a tiny percentage of "ancestor simulations" were run (that is, "high-fidelity" simulations of ancestral life that would be indistinguishable from reality to the simulated ancestor), the total number of simulated ancestors, or "Sims", in the universe (or multiverse, if it exists) would greatly exceed the total number of actual ancestors. Bostrom uses a type of anthropic reasoning to claim that, if the third proposition is the one of those three that is true, and almost all people live in simulations, then humans are almost certainly living in a simulation. Bostrom's argument rests on the premise that given sufficiently advanced technology, it would be possible to represent the populated surface of the Earth without


id: simulation-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Simulation_hypothesis-2.md
category: reference
title: Simulation hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simulation_hypothesis
date_saved: 2026-05-05T10:00:29.485787+00:00
instance: kb-cron
parent: simulation-hypothesis-20260505-0
summary:
Bostrom argues that if "the fraction of all people with our kind of experiences that are living in a simulation is very close to one", then it follows that humans probably live in a simulation. Some philosophers disagree, proposing that perhaps "Sims" do not have conscious experiences the same way that unsimulated humans do, or that it can otherwise be self-evident to a human that they are a human rather than a Sim. Philosopher Barry Dainton modifies Bostrom's trilemma by substituting "neural ancestor simulations" (ranging from literal brains in a vat, to far-future humans with induced high-fidelity hallucinations that they are their own distant ancestors) for Bostrom's "ancestor simulations", on the grounds that every philosophical school of thought can agree that sufficiently high-tech neural ancestor simulation experiences would be indistinguishable from non-simulated experiences. Even if high-fidelity computer Sims are never conscious, Dainton's reasoning leads to the following conclusion: either the fraction of human-level civilizations that reach a posthuman stage and are able and willing to run large numbers of neural ancestor simulations is close to zero, or some kind of (possibly neural) ancestor simulation exists. The hypothesis has received criticism from some physicists, such as Sabine Hossenfelder, who considers that


id: simulation-hypothesis-20260505-3
file: data/en.wikipedia.org/wiki/Simulation_hypothesis-3.md
category: reference
title: Simulation hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simulation_hypothesis
date_saved: 2026-05-05T10:00:29.485787+00:00
instance: kb-cron
parent: simulation-hypothesis-20260505-0
summary:
Some scholars accept the trilemma, and argue that the first or second of the propositions are true, and that the third proposition (the proposition that humans live in a simulation) is false. Physicist Paul Davies uses Bostrom's trilemma as part of one possible argument against a near-infinite multiverse. This argument runs as follows: if there were a near-infinite multiverse, there would be posthuman civilizations running ancestor simulations, which would lead to the untenable and scientifically self-defeating conclusion that humans live in a simulation; therefore, by reductio ad absurdum, existing multiverse theories are likely false. (Unlike Bostrom and Chalmers, Davies (among others) considers the simulation hypothesis to be self-defeating.) Some point out that there is currently no proof of technology that would facilitate the existence of sufficiently high-fidelity ancestor simulation. Additionally, there is no proof that it is physically possible or feasible for a posthuman civilization to create such a simulation, and therefore for the present, the first proposition must be taken to be true. Additionally there are limits of computation. Physicist Marcelo Gleiser objects to the notion that posthumans would have a reason to run simulated universes: "...being so advanced they would have collected enough knowledge about their past to


id: simulation-hypothesis-20260505-4
file: data/en.wikipedia.org/wiki/Simulation_hypothesis-4.md
category: reference
title: Simulation hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simulation_hypothesis
date_saved: 2026-05-05T10:00:29.485787+00:00
instance: kb-cron
parent: simulation-hypothesis-20260505-0
summary:
In many respects this point of view may be nothing more than a result of the fact that the notion of computation is the disease of our age—everywhere we look today we see examples of computers, computation, and information theory and thus we extrapolate this to our laws of physics. Indeed, thinking about computing as arising from faulty components, it seems as if the abstraction that uses perfectly operating computers is unlikely to exist as anything but a platonic ideal. Another critique of such a point of view is that there is no evidence for the kind of digitization that characterizes computers nor are there any predictions made by those who advocate such a view that have been experimentally confirmed. === Testing the hypothesis physically === A method to test one type of simulation hypothesis was proposed in 2012 by physicists Silas R. Beane, Zohreh Davoudi, and Martin J. Savage. Under the assumption of finite computational resources, the simulation of the universe would be performed by dividing the space-time continuum into a discrete set of points, which may result in observable effects. In analogy with the mini-simulations that lattice-gauge theorists run today to build up nuclei from the underlying theory


id: simulation-hypothesis-20260505-5
file: data/en.wikipedia.org/wiki/Simulation_hypothesis-5.md
category: reference
title: Simulation hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Simulation_hypothesis
date_saved: 2026-05-05T10:00:29.485787+00:00
instance: kb-cron
parent: simulation-hypothesis-20260505-0
summary:
== In popular culture == The simulation hypothesis and related themes like simulated reality have been explored in literature, film and theatre. Simulacron-3 (1964) by Daniel F. Galouye is an early exploration of a computer-simulated city and inspired screen adaptations including World on a Wire (1973) and, later, The Thirteenth Floor (1999). The Matrix (1999) popularized the idea of humanity unknowingly living inside a machine-generated virtual reality. In Overdrawn at the Memory Bank (1983/1984), the protagonist undergoes compulsory “doppling” therapy that transfers his consciousness, and—after a mishap—his mind is kept inside the corporation's central computer. Theatre has also treated the topic. Jay Scheib’s 2012 play World of Wires was explicitly inspired by Bostrom’s simulation argument and by Fassbinder’s World on a Wire. Philip K. Dick’s short story “We Can Remember It for You Wholesale” (1966)—about implanted memories and unstable realities—formed the basis for Total Recall (1990) and its 2012 remake. In 2025, Italian creative director and producer Giorgio Fazio released the two-track project Nothing But Simulation, thematically tied to the simulation hypothesis and paired with a generative web experience. == See also == Artificial life Artificial society Boltzmann brain Brain in a vat Digital physics Interface theory Fine-tuned universe Holographic


id: slavery-hypertension-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Slavery_hypertension_hypothesis-0.md
category: reference
title: Slavery hypertension hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Slavery_hypertension_hypothesis
date_saved: 2026-05-05T10:00:30.683380+00:00
instance: kb-cron
parent: slavery-hypertension-hypothesis-20260505-0
summary:
The slavery hypertension hypothesis proposes that disproportionately high rates of hypertension among black people in the New World are due to selective pressure preferring individuals who retain more sodium among black slaves during the Middle Passage. == History == It was originally proposed in 1983 by Clarence Grim and Thomas W. Wilson, who subsequently promoted it heavily during the remainder of the 1980s. It gained considerable media attention when Grim presented it at a conference in 1988. In 1990, the first medical textbook mentioning the hypothesis was published. The first peer-reviewed paper advancing the hypothesis was published by Wilson and Grim in 1991. This study also received considerable media attention. In December 2004, a paper titled CYP3A Variation and the Evolution of Salt-Sensitivity Variants was published which drew attention to the importance of the CPY3A5*1 and CPY3A5*3 alleles of cytochrome P450 CYP3A5 in hypertensive disease. The paper showed a substantial correlation between geographical latitude and the CPY3A5 allele distribution, with African Americans descended from the slave trade having retained the equatorial haplotype. In 2005 the thesis that black Americans who trace their immigration to the slave era experience lower life expectancy due to hypertensive disease associated with the slave trade


id: snowball-earth-20260505-0
file: data/en.wikipedia.org/wiki/Snowball_Earth-0.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
The Snowball Earth is a geohistorical hypothesis proposing that during one or more of Earth's icehouse climates, the planet's surface was nearly entirely frozen, with little or no liquid water exposed. This global glaciation hypothesis is most commonly associated with the Cryogenian Period, which included two major glacial episodes: the Sturtian (c. 717–660 Ma) and Marinoan (c. 650–635 Ma). Proponents of the hypothesis argue that it best explains sedimentary deposits that are generally believed to be of glacial origin at tropical palaeolatitudes and other enigmatic features in the geological record. Opponents of the hypothesis contest the geological evidence for global glaciation and the geophysical feasibility of an ice- or slush-covered ocean, and they emphasize the difficulty of escaping an all-frozen condition. Several unanswered questions remain, including whether Earth was a full "snowball" or a "slushball" with a thin equatorial band of open (or seasonally open) water. The Snowball Earth episodes are proposed to have occurred before the sudden radiations of multicellular bioforms known as the Avalon and Cambrian explosions; the most recent Snowball episode may have triggered the evolution of multicellularity. == History == === First evidence for ancient glaciation === Long before the idea of a global glaciation was


id: snowball-earth-20260505-1
file: data/en.wikipedia.org/wiki/Snowball_Earth-1.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
That a bed contains sedimentary structures that could have been formed only by glacial activity; That the bed lay within the tropics when it was deposited. That glaciers were active at different global locations at the same time, and that no other deposits of the same age are in existence. This last point is very difficult to prove. Before the Ediacaran, the biostratigraphic markers usually used to correlate rocks are absent; therefore there is no way to prove that rocks in different places across the globe were deposited at the same time. The best that can be done is to estimate the age of the rocks using radiometric dating, which are rarely accurate to better than a million years or so. The first two points are often the source of contention on a case-to-case basis. Many glacial features can also be formed by non-glacial means, and estimating the approximate latitudes of landmasses even as recently as 200 Ma can be riddled with difficulties. === Palaeomagnetism === The snowball Earth hypothesis was first posited to explain what were then considered to be glacial deposits near the equator. Since tectonic plates move slowly over time, ascertaining their position at a given point


id: snowball-earth-20260505-2
file: data/en.wikipedia.org/wiki/Snowball_Earth-2.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
=== Open-water deposits === It appears that some deposits formed during the snowball period could only have formed in the presence of an active hydrological cycle. Bands of glacial deposits up to 5,500 meters thick, separated by small (meters) bands of non-glacial sediments, demonstrate that glaciers melted and re-formed repeatedly for tens of millions of years; solid oceans would not permit this scale of deposition. It is considered possible that ice streams such as seen in Antarctica today could have caused these sequences. Further, sedimentary features that could only form in open water (for example: wave-formed ripples, far-traveled ice-rafted debris and indicators of photosynthetic activity) can be found throughout sediments dating from the snowball-Earth periods. While these may represent "oases" of meltwater on a completely frozen Earth, computer modelling suggests that large areas of the ocean must have remained ice-free, arguing that a "hard" snowball is not plausible in terms of energy balance and general circulation models. === Carbon isotope ratios === There are two stable isotopes of carbon in sea water: carbon-12 (12C) and the rare carbon-13 (13C), which makes up about 1.109 percent of carbon atoms. Biochemical processes, of which photosynthesis is one, tend to preferentially incorporate the


id: snowball-earth-20260505-3
file: data/en.wikipedia.org/wiki/Snowball_Earth-3.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
These cap carbonates have unusual chemical composition as well as strange sedimentary structures that are often interpreted as large ripples. The formation of such sedimentary rocks could be caused by a large influx of positively charged ions, as would be produced by rapid weathering during the extreme greenhouse following a snowball Earth event. The δ13C isotopic signature of the cap carbonates is near −5‰, consistent with the value of the mantle—such a low value could be taken to signify an absence of life, since photosynthesis usually acts to raise the value; alternatively the release of methane deposits could have lowered it from a higher value and counterbalance the effects of photosynthesis. The mechanism involved in the formation of cap carbonates is not clear, but the most cited explanation suggests that at the melting of a snowball Earth, water would dissolve the abundant CO2 from the atmosphere to form carbonic acid, which would fall as acid rain. This would weather exposed silicate and carbonate rock (including readily attacked glacial debris), releasing large amounts of calcium, which when washed into the ocean would form distinctively textured layers of carbonate sedimentary rock. Such an abiotic "cap carbonate" sediment can be found on top


id: snowball-earth-20260505-4
file: data/en.wikipedia.org/wiki/Snowball_Earth-4.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
=== Initiation of glaciation === A tropical distribution of the continents is, perhaps counter-intuitively, necessary to allow the initiation of a snowball Earth. Tropical continents are more reflective than open ocean and so absorb less of the Sun's heat: most absorption of solar energy on Earth today occurs in tropical oceans. Further, tropical continents are subject to more rainfall, which leads to increased river discharge and erosion. When exposed to air, silicate rocks undergo weathering reactions which remove carbon dioxide from the atmosphere. These reactions proceed in the general form An example of such a reaction is the weathering of wollastonite: The released calcium cations react with the dissolved bicarbonate in the ocean to form calcium carbonate as a chemically precipitated sedimentary rock. This transfers carbon dioxide, a greenhouse gas, from the air into the geosphere, and, in steady-state on geologic time scales, offsets the carbon dioxide emitted from volcanoes into the atmosphere. As of 2003, a precise continental distribution during the Neoproterozoic was difficult to establish because there were too few suitable sediments for analysis. Some reconstructions point towards polar continents—which have been a feature of all other major glaciations, providing a point upon which ice can nucleate. Changes


id: snowball-earth-20260505-5
file: data/en.wikipedia.org/wiki/Snowball_Earth-5.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
=== Breaking out of global glaciation === The carbon dioxide levels necessary to thaw Earth have been estimated as being 350 times what they are today, about 13% of the atmosphere. Since Earth was almost completely covered with ice, carbon dioxide could not be withdrawn from the atmosphere by release of alkaline metal ions weathering out of siliceous rocks. Over 4 to 30 million years, enough CO2 and methane, mainly emitted by volcanoes but also produced by microbes converting organic carbon trapped under the ice into the gas, would accumulate to finally cause enough greenhouse effect to make surface ice melt in the tropics until a band of permanently ice-free land and water developed; this would be darker than the ice and thus absorb more energy from the Sun—initiating a "positive feedback". The first areas to become free of permanent ice cover may have been in the mid-latitudes rather than in the tropics, because a rapid hydrological cycle would have inhibited the melting of ice at low latitudes. As these mid-latitude regions became ice free, dust from them blew over onto ice sheets elsewhere, decreasing their albedo and accelerating the process of deglaciation. Destabilization of substantial deposits of methane hydrates


id: snowball-earth-20260505-6
file: data/en.wikipedia.org/wiki/Snowball_Earth-6.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
== Scientific dispute == The argument against the hypothesis is evidence of fluctuation in ice cover and melting during "snowball Earth" deposits. Evidence for such melting comes from evidence of glacial dropstones, geochemical evidence of climate cyclicity, and interbedded glacial and shallow marine sediments. A longer record from Oman, constrained to 13°N, covers the period from 712 to 545 million years ago—a time span containing the Sturtian and Marinoan glaciations—and shows both glacial and ice-free deposition. The snowball Earth hypothesis does not explain the alternation of glacial and interglacial events, nor the oscillation of glacial sheet margins. There have been difficulties in recreating a snowball Earth with global climate models. Simple GCMs with mixed-layer oceans can be made to freeze to the equator; a more sophisticated model with a full dynamic ocean (though only a primitive sea ice model) failed to form sea ice to the equator. In addition, the levels of CO2 necessary to melt a global ice cover have been calculated to be 130,000 ppm, which is considered by some to be unreasonably large. Strontium isotopic data have been found to be at odds with proposed snowball Earth models of silicate weathering shutdown during glaciation and rapid rates


id: snowball-earth-20260505-7
file: data/en.wikipedia.org/wiki/Snowball_Earth-7.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
In reservoirs of anaerobic and low-oxygen life powered by chemicals in deep oceanic hydrothermal vents surviving in Earth's deep oceans and crust; but photosynthesis would not have been possible there. Under the ice layer, in chemolithotrophic (mineral-metabolizing) ecosystems theoretically resembling those in existence in modern glacier beds, high-alpine and Arctic talus permafrost, and basal glacial ice. This is especially plausible in areas of volcanism or geothermal activity. In pockets of liquid water within and under the ice caps, similar to Lake Vostok in Antarctica. In theory, this system may resemble microbial communities living in the perennially frozen lakes of the Antarctic dry valleys. Photosynthesis can occur under ice up to 20 m thick, and at the temperatures predicted by models, equatorial sublimation would prevent equatorial ice thickness from exceeding 10 m. As eggs and dormant cells and spores deep-frozen into ice during the most severe phases of the frozen period. In small regions of open sea water: polynya. These natural ice holes can occur from the action of winds, currents or a local heat source (e.g. geothermal), even if the surrounding sea is completely frozen over. They could preserve enclaves of photosynthesizers with access to light and CO2 to generate


id: snowball-earth-20260505-8
file: data/en.wikipedia.org/wiki/Snowball_Earth-8.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
The Neoproterozoic was a time of remarkable diversification of multicellular organisms, including animals. Organism size and complexity increased considerably after the end of the snowball glaciations. This rapid development of multicellular organisms may have been the result of increased evolutionary pressures resulting from multiple icehouse-hothouse cycles; in this sense, snowball Earth episodes may have "pumped" evolution, much as glaciations during the Pleistocene are known to have acted as a diversity pump in Antarctica. Alternatively, fluctuating copper levels and rising oxygen may have played a part. Many Sturtian diamictites unconformably overlie copper-mineralised strata in Greenland, North America, Australia, and Africa; the glacial breakup and erosion of rocks heavily enriched in copper during the Sturtian glaciation, combined with the chemical weathering of the Franklin Large Igneous Province, greatly elevated copper concentrations in the ocean. Because copper is an essential component of many proteins involved in mitigating oxygen toxicity, synthesising adenosine triphosphate, and producing elastin and collagen, among other biological functions, this spike in copper concentrations was essential to the explosive evolution of multicellular life throughout the latter portion of the Neoproterozoic. Elevated copper concentrations persisted into the Cambrian explosion at the beginning of the Phanerozoic and likely influenced its course too. One


id: snowball-earth-20260505-9
file: data/en.wikipedia.org/wiki/Snowball_Earth-9.md
category: reference
title: Snowball Earth
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Snowball_Earth
date_saved: 2026-05-05T10:00:31.903477+00:00
instance: kb-cron
parent: snowball-earth-20260505-0
summary:
The Snowball Earth 1999 overview by Paul F. Hoffman and Daniel P. Schrag, 8 August 1999 Snowball Earth web site Exhaustive on-line resource for snowball Earth by pro-snowball scientists Hoffman and Schrag. New Evidence Puts 'Snowball Earth' Theory Out In The Cold sciencedaily.com. 2007. Analyses in Oman produce evidence of hot-cold cycles in the Cryogenian period, roughly 850–544 million years ago. The UK-Swiss team claims that this evidence undermines hypotheses of an ice age so severe that Earth's oceans completely froze over. Channel 4 (UK) documentary, Catastrophe: Snowball Earth Archived 29 May 2016 at the Wayback Machine episode 2 of 5, first screened Dec 2008, documentary narrated by Tony Robinson, advocates snowball Earth and contains interviews with proponents. First breath: Earth's billion-year struggle for oxygen New Scientist, #2746, 5 February 2010 by Nick Lane. Posits an earlier much longer snowball period, c. 2.4 – c. 2.0 Gya, triggered by the Great Oxygenation Event. 'Snowball Earth' theory melted BBC News online (2002-03-06) report on findings by geoscientists at the University of St Andrews, Scotland that casts doubt on the snowball Earth hypothesis due to evidence of sedimentary material, which could only have been derived from floating ice on open oceanic waters.


id: somatic-marker-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Somatic_marker_hypothesis-0.md
category: reference
title: Somatic marker hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Somatic_marker_hypothesis
date_saved: 2026-05-05T10:00:33.152759+00:00
instance: kb-cron
parent: somatic-marker-hypothesis-20260505-0
summary:
The somatic marker hypothesis, formulated by Antonio Damasio and associated researchers, proposes that emotional processes guide (or bias) behavior, particularly decision-making. "Somatic markers" are feelings in the body that are associated with emotions, such as the association of rapid heartbeat with anxiety or of nausea with disgust. According to the hypothesis, somatic markers strongly influence subsequent decision-making. Within the brain, somatic markers are thought to be processed in the ventromedial prefrontal cortex (vmPFC) and the amygdala. The hypothesis has been tested in experiments using the Iowa gambling task. == Background == In economic theory, human decision-making is often modeled as being devoid of emotions, involving only logical reasoning based on cost-benefit calculations. In contrast, the somatic marker hypothesis proposes that emotions play a critical role in the ability to make fast, rational decisions in complex and uncertain situations. Patients with frontal lobe damage, such as Phineas Gage, provided the first evidence that the frontal lobes were associated with decision-making. Frontal lobe damage, particularly to the vmPFC, results in impaired abilities to organize and plan behavior and learn from previous mistakes, without affecting intellect in terms of working memory, attention, and language comprehension and expression. vmPFC patients also have difficulty expressing


id: somatic-marker-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Somatic_marker_hypothesis-1.md
category: reference
title: Somatic marker hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Somatic_marker_hypothesis
date_saved: 2026-05-05T10:00:33.152759+00:00
instance: kb-cron
parent: somatic-marker-hypothesis-20260505-0
summary:
In an effort to produce a simple neuropsychological tool that would assess deficits in emotional processing, decision-making, and social skills of OMPFC-lesioned individuals, Bechara and collaborators created the Iowa gambling task. The task measures a form of emotion-based learning. Studies using the gambling task have found deficits in various neurological (such as amygdala and OMPFC lesions) and psychiatric populations (such as schizophrenia, mania, and drug abusers). The Iowa gambling task is a computerized test in which participants are presented with four decks of cards from which they repeatedly choose. Each deck contains various amounts of rewards of either $50 or $100, and occasional losses that are greater in the decks with higher rewards. The participants do not know where the penalty cards are located, and are told to pick cards that will maximize their winnings. The most profitable strategy turns out to be to choose cards only from the small reward/small penalty decks, because although the reward is smaller, the penalty is proportionally much smaller than in the high reward/high penalty decks. Over the course of a session, most healthy participants come to adopt the profitable low-penalty deck strategy. Participants with brain damage, however, are unable to determine the better


id: somatic-marker-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Somatic_marker_hypothesis-2.md
category: reference
title: Somatic marker hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Somatic_marker_hypothesis
date_saved: 2026-05-05T10:00:33.152759+00:00
instance: kb-cron
parent: somatic-marker-hypothesis-20260505-0
summary:
Some researchers believe that the use of somatic markers (i.e., afferent feedback) would be a very inefficient method of influencing behavior. Damasio's notion of the as-if experience dependent feedback route, whereby bodily responses are re-represented utilizing the somatosensory cortex (postcentral gyrus), also proposes an inefficient method of affecting explicit behavior. Edmund Rolls (1999) stated that; "it would be very inefficient and noisy to place in the execution route a peripheral response, and transducers to attempt to measure that peripheral response, itself a notoriously difficult procedure" (p. 73). Reinforcement association located in the orbitofrontal cortex and amygdala, where the incentive value of stimuli is decoded, is sufficient to elicit emotion-based learning and to affect behavior via, for example, the orbitofrontal-striatal pathway. This process can occur via implicit or explicit processes. The somatic marker hypothesis represents a model of how feedback from the body may contribute to both advantageous and disadvantageous decision-making in situations of complexity and uncertainty. Much of its supporting data comes from data taken from the Iowa gambling task. While the Iowa gambling task has proven to be an ecologically valid measure of decision-making impairment, there exist three assumptions that need to hold true. First, the claim that it


id: space-animal-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Space_animal_hypothesis-0.md
category: reference
title: Space animal hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Space_animal_hypothesis
date_saved: 2026-05-05T10:00:34.416085+00:00
instance: kb-cron
parent: space-animal-hypothesis-20260505-0
summary:
The space animal hypothesis proposes that reports of flying saucers or UFOs might be caused not by technological alien spacecraft or mass hysteria, but rather by animal lifeforms ("space critters") that are indigenous to Earth's atmosphere or interplanetary space. == Proponents == Multiple authors independently suggested the space animal hypothesis. In 1923, paranormal author Charles Fort mused, "It seems no more incredible that up in the seemingly unoccupied sky there should be hosts of living things than that the seeming blank of the ocean should swarm with life." During the 1947 flying disc craze, a fan of Fort's writings named John Philip Bessor became the first modern proponent of the hypothesis when he authored a letter to the Air Force suggesting that discs might be "animals bearing very little likeness to human beings". In 1949, he wrote to the Saturday Evening Post to suggest that the discs might be "more like octopuses, in mentality, than humans". In 1957, a saucer group's newsletter credited Bessor with the "space animal" idea, and in 1978 he was called the "grand-daddy" of the "space critter" hypothesis. In 1948, the Saturday Evening Post quoted Luis Walter Alvarez's opinion that the "gizmos" appeared to be "alive".


id: trivers-willard-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Trivers–Willard_hypothesis-0.md
category: reference
title: Trivers–Willard hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Trivers–Willard_hypothesis
date_saved: 2026-05-05T10:00:35.561406+00:00
instance: kb-cron
parent: trivers-willard-hypothesis-20260505-0
summary:
In evolutionary biology and evolutionary psychology, the Trivers–Willard hypothesis, formally proposed by Robert Trivers and Dan Willard in 1973, suggests that female mammals adjust the sex ratio of offspring in response to maternal condition, so as to maximize their reproductive success (fitness). For example, it may predict greater parental investment in males by parents in "good conditions" and greater investment in females by parents in "poor conditions" (relative to parents in good conditions). The reasoning for this prediction is as follows: Assume that parents have information on the sex of their offspring and can influence their survival differentially. While selection pressures exist to maintain a 1:1 sex ratio, evolution will favor local deviations from this if one sex has a likely greater reproductive payoff than is usual. Trivers and Willard also identified a circumstance in which reproducing individuals might experience deviations from expected offspring reproductive value—namely, varying maternal condition. In polygynous species, males may mate with multiple females, and low-condition males will achieve fewer or no matings. Parents in relatively good condition would then be under selection for mutations causing production and investment in sons (rather than daughters), because of the increased chance of mating experienced by these good-condition sons.


id: two-gospel-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Two-gospel_hypothesis-0.md
category: reference
title: Two-gospel hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Two-gospel_hypothesis
date_saved: 2026-05-05T10:00:36.789683+00:00
instance: kb-cron
parent: two-gospel-hypothesis-20260505-0
summary:
The two-gospel hypothesis or Griesbach hypothesis is that the Gospel of Matthew was written before the Gospel of Luke, and that both were written earlier than the Gospel of Mark. It is a proposed solution to the synoptic problem, which concerns the pattern of similarities and differences between the three Gospels of Matthew, Mark, and Luke. The hypothesis is generally first credited to Johann Jakob Griesbach writing in the 1780s; it was introduced in its current form by William R. Farmer in 1964 and given its current designation of two-gospel hypothesis in 1979. The two-gospel hypothesis contrasts with the two-source hypothesis, the most popular and accepted scholarly hypothesis. Supporters say that it does not require lost sources like the Q source and was supported by the early Church. Proponents of the two-gospel hypothesis generally also support the traditional claims of authorship as accurate to disciples and their direct associates, which implies the gospels were written comparatively soon after Jesus's death, rather than the later dates of authorship supported by other schools of thought. == Overview == Those who support the hypothesis often accept all the church tradition as reliable. Therefore, a common formulation of the hypothesis is the following: Matthew


id: two-gospel-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Two-gospel_hypothesis-1.md
category: reference
title: Two-gospel hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Two-gospel_hypothesis
date_saved: 2026-05-05T10:00:36.789683+00:00
instance: kb-cron
parent: two-gospel-hypothesis-20260505-0
summary:
== Contrasted with the two-source hypothesis == Proponents generally separate arguments made from the text of the gospels themselves ("internal evidence") and evidence from preserved writings of the early church ("external evidence"). For example, early church documents claim that Mark's Gospel was created after Mark made fifty copies of a series of speeches that Peter had given in Rome. The two-gospel hypothesis leans heavily on this external evidence: it embraces the views of the early church, and claims that a strong reason needs to be provided to justify dismissing the traditions of the early Church maintained over the authorship of the gospels. It also claims that the internal evidence supports Mark being a redactor of Matthew and Luke, as Griesbach argued. The two-source hypothesis, in contrast, is based only on the perceived internal evidence for Marcan priority, such as the brevity and primitivity of Mark, and does not accept the tradition of the early church. Approximately 25% of Matthew and 25% of Luke are identical, but are not found in Mark. This has been explained in the two-source hypothesis as coming from the hypothetical Q document. By the two-gospel hypothesis, this material was copied by Luke from Matthew, but not


id: two-gospel-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Two-gospel_hypothesis-2.md
category: reference
title: Two-gospel hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Two-gospel_hypothesis
date_saved: 2026-05-05T10:00:36.789683+00:00
instance: kb-cron
parent: two-gospel-hypothesis-20260505-0
summary:
If Luke had access to the final version of Matthew (as opposed to both drawing independently on other sources), why are there so many significant differences between Luke and Matthew on issues such as Jesus' genealogy, circumstances of birth, and events following resurrection? While Luke and Matthew do share a lot of text which is not present in Mark, almost all of it is confined to teachings and parables. Construction of the gospels in accordance with the two-gospel hypothesis would require Luke to rewrite major parts of Matthew's narrative – even though Matthew was presumably an eyewitness who lived in Jerusalem and was surrounded by other eyewitnesses, and Luke was neither. This hypothesis does not actually necessitate Luke relying on Matthew, only Mark relying on Luke and Matthew. Many proponents argue instead that both Luke and Matthew drew from a "proto-Matthew." "The argument from omission": why would Mark and Peter omit such remarkable and miraculous events as virgin birth of Jesus and particularly his appearance to apostles following resurrection? Both Matthew and Luke explicitly attest that Jesus appeared to the eleven disciples, including Peter, after his resurrection, and it seems incredible that Peter would not testify to that fact in


id: variable-speed-of-light-20260505-0
file: data/en.wikipedia.org/wiki/Variable_speed_of_light-0.md
category: reference
title: Variable speed of light
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Variable_speed_of_light
date_saved: 2026-05-05T10:00:38.002917+00:00
instance: kb-cron
parent: variable-speed-of-light-20260505-0
summary:
A variable speed of light (VSL) is a feature of a family of hypotheses stating that the speed of light may in some way not be constant, for example, that it varies with frequency, in space, or over time. Accepted classical theories of physics, and in particular general relativity, predict a constant speed of light in any local frame of reference and in some situations these predict apparent variations of the speed of light depending on frame of reference, but this article does not refer to this as a variable speed of light. Various alternative theories of gravitation and cosmology, many of them non-mainstream, incorporate variations in the local speed of light. Attempts to incorporate a variable speed of light into physics were made by Robert Dicke in 1957, and by several researchers starting from the late 1980s. VSL should not be confused with faster than light theories, which depends on a medium's refractive index or its measurement in a remote observer's frame of reference in a gravitational potential. In this context, the "speed of light" refers to the limiting speed c of the theory rather than to the velocity of propagation of photons. == Historical proposals == === Background


id: variable-speed-of-light-20260505-1
file: data/en.wikipedia.org/wiki/Variable_speed_of_light-1.md
category: reference
title: Variable speed of light
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Variable_speed_of_light
date_saved: 2026-05-05T10:00:38.002917+00:00
instance: kb-cron
parent: variable-speed-of-light-20260505-0
summary:
One group, studying distant quasars, has claimed to detect a variation of the fine-structure constant at the level in one part in 105. Other authors dispute these results. Other groups studying quasars claim no detectable variation at much higher sensitivities. The natural nuclear reactor of Oklo has been used to check whether the atomic fine-structure constant α might have changed over the past 2 billion years. That is because α influences the rate of various nuclear reactions. For example, 149Sm captures a neutron to become 150Sm, and since the rate of neutron capture depends on the value of α, the ratio of the two samarium isotopes in samples from Oklo can be used to calculate the value of α from 2 billion years ago. Several studies have analysed the relative concentrations of radioactive isotopes left behind at Oklo, and most have concluded that nuclear reactions then were much the same as they are today, which implies α was the same too. Paul Davies and collaborators have suggested that it is in principle possible to disentangle which of the dimensionful constants (the elementary charge, the Planck constant, and the speed of light) of which the fine-structure constant is composed is responsible


id: virus-world-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Virus_world_hypothesis-0.md
category: reference
title: Virus world hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Virus_world_hypothesis
date_saved: 2026-05-05T10:00:39.173467+00:00
instance: kb-cron
parent: virus-world-hypothesis-20260505-0
summary:
The virus world hypothesis (also called the co-evolution hypothesis or the virus-first hypothesis) proposes that self-replicating virus-like genetic elements existed before cellular life and contributed to its emergence. It is one of the main frameworks used to explain the origin of viruses. Modern viruses are obligate parasites that depend on their cellular hosts, thus it may seem more intuitive for viruses to have originated from cells, such as in the "escape hypothesis". Nevertheless, under a hypothesized virus world, viruses are theorized to be direct descendants of the very first replicons to arise. These primordial soup dwelling replicons could have evolved into archaic virus-like structures, which in turn became the precursors of cellular life forms, with the latter possibly emerging as factories and reservoirs for virus production and dissemination. The hypothesis is considered one of the three classical hypotheses of viral origin, although it is now thought these hypotheses may not be mutually exclusive, as different groups of viruses may have evolved through different routes, or a "chimeric scenario". == History == The idea that viruses represent primordial, pre-cellular forms of life has roots in the earliest decades of virology. Félix d'Hérelle, discoverer of bacteriophages, proposed that virus-like agents might be


id: virus-world-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Virus_world_hypothesis-1.md
category: reference
title: Virus world hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Virus_world_hypothesis
date_saved: 2026-05-05T10:00:39.173467+00:00
instance: kb-cron
parent: virus-world-hypothesis-20260505-0
summary:
=== Chimeric scenario === More recent work has treated the classical hypotheses as complementary. Krupovic, Dolja, and Koonin have proposed a chimeric scenario in which viral replication modules descended from primordial pre-cellular replicators, consistent with the virus-first view, while genes encoding major capsid proteins were independently recruited from cellular hosts at multiple points during the diversification of the virosphere, consistent with the escape hypothesis. New viral lineages could then continue to emerge from cellular sources throughout evolutionary history, explaining the polyphyletic character of the modern viruses. == Criticism == The main issue with the virus world is that all known viruses require a host cell for replication, making a pre-cellular virus inconsistent with the standard definition of a virus as an obligate intracellular parasite. Therefore, the hypothesis has been challenged and the existence of an ancient and independent viral world critiqued. Moreira and López-García of Paris-Saclay University have said that they do not think viruses are older than LUCA and claimed that scientific evidence downright the dismisses the idea. The pair has contended that virus hallmark genes could derive from ancient cellular lineages now extinct, and that viruses lack the structural historical continuity required for inclusion on a tree of


id: weak-continuum-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Weak_continuum_hypothesis-0.md
category: reference
title: Weak continuum hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weak_continuum_hypothesis
date_saved: 2026-05-05T10:00:40.333929+00:00
instance: kb-cron
parent: weak-continuum-hypothesis-20260505-0
summary:
The term weak continuum hypothesis can be used to refer to the hypothesis that 2 ℵ 0 < 2 ℵ 1 {\displaystyle 2^{\aleph _{0}}<2^{\aleph _{1}}} , which is the negation of the second continuum hypothesis. It is equivalent to a weak form of ◊ on ℵ 1 {\displaystyle \aleph _{1}} . F. Burton Jones proved that if it is true, then every separable normal Moore space is metrizable. Weak continuum hypothesis may also refer to the assertion that every uncountable set of real numbers can be placed in bijective correspondence with the set of all reals. This second assertion was Cantor's original form of the Continuum Hypothesis (CH). Given the Axiom of Choice, it is equivalent to the usual form of CH, that 2 ℵ 0 = ℵ 1 {\displaystyle 2^{\aleph _{0}}=\aleph _{1}} . == References ==


id: weathering-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Weathering_hypothesis-0.md
category: reference
title: Weathering hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weathering_hypothesis
date_saved: 2026-05-05T10:00:41.568680+00:00
instance: kb-cron
parent: weathering-hypothesis-20260505-0
summary:
Arline Geronimus wrote about the weathering hypothesis the early 1990s to account for health disparities of newborn babies and birth mothers due to decades and generations of racism and social, economic, and political oppression. It is well documented that people of color and other marginalized communities have worse health outcomes than white people. This is due to multiple stressors including prejudice, social alienation, institutional bias, political oppression, economic exclusion, and racial discrimination. The weathering hypothesis proposes that the cumulative burden of these stressors as individuals age is "weathering", and the increased weathering experienced by minority groups compared to others can account for differences in health outcomes. In recent years, social scientists investigated the biological plausibility of the weathering hypothesis in studies evaluating the physiological effects of social, environmental and political stressors among marginalized communities. The weathering hypothesis is more widely accepted as a framework for explaining health disparities on the basis of differential exposure to racially based stressors. Researchers have also identified patterns connecting weathering to biological phenomena associated with stress and aging, such as allostatic load, epigenetics, telomere shortening, and accelerated brain aging. == Origins == The weathering hypothesis was initially formulated by Arline Geronimus to explain the dire


id: weathering-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Weathering_hypothesis-1.md
category: reference
title: Weathering hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weathering_hypothesis
date_saved: 2026-05-05T10:00:41.568680+00:00
instance: kb-cron
parent: weathering-hypothesis-20260505-0
summary:
Maternal mortality is three to four times higher for Black mothers than white mothers in the United States. Infant mortality is also twice as high for infants born to non-Hispanic Black mothers compared to infants born to non-Hispanic white mothers. Additionally, there are racial disparities for negative birth outcomes like low birth weight, which has been found to influence risk of infant mortality and developmental outcomes after birth, and preterm birth. Across all women, older maternal age is associated with higher rates of these negative outcomes during pregnancy, but studies have consistently found that rates rise more rapidly for Black women than white women. The weathering hypothesis proposes that the accumulation of racial stress over Black women's lives contributes to this observed pattern of racial disparities in maternal health and birth outcomes that increase with maternal age. Research has consistently identified an association between preterm birth and low birth weight in Black women and maternal stress caused by experiences of racism, systemic bias, socioeconomic disadvantage, segregated neighborhoods, and high rates of violent crime. There is biological evidence of weathering, including the finding that Black women have shorter telomeres, a biological indicator of age, when compared with white women of the


id: widom-larsen-theory-20260505-0
file: data/en.wikipedia.org/wiki/Widom–Larsen_theory-0.md
category: reference
title: Widom–Larsen theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Widom–Larsen_theory
date_saved: 2026-05-05T10:00:42.763603+00:00
instance: kb-cron
parent: widom-larsen-theory-20260505-0
summary:
The Widom–Larsen theory is a proposed explanation for supposed Low Energy Nuclear Reactions (LENR) developed in 2005 by Allan Widom and Lewis Larsen. In the paper describing the idea, they claim that ultra low momentum neutrons are produced in the cold fusion apparatuses during weak interactions when protons capture "heavy" electrons from metallic hydride surfaces. One source has held that it is "unlikely the electron energy threshold for neutron production can be reached in a metal lattice system without a substantial energy input". The idea was expanded by Yogendra Srivastava together with Widom and Larsen in 2014, who went on to propose that it could be an explanation for neutrons observed in exploding wire experiments, solar corona and flares, and neutron production in thunderstorms. However, unrealistic concentrations of free electrons are needed for the neutron yield to be a significant component of thunderstorm neutrons, discounting the explanation. == References ==


id: wiseman-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Wiseman_hypothesis-0.md
category: reference
title: Wiseman hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wiseman_hypothesis
date_saved: 2026-05-05T10:00:43.966901+00:00
instance: kb-cron
parent: wiseman-hypothesis-20260505-0
summary:
The Wiseman hypothesis, sometimes called the tablet theory, is a theory of the authorship and composition of the Book of Genesis which suggests that Moses compiled Genesis from tablets handed down through Abraham and the other patriarchs. Originally advocated by P. J. Wiseman (1888–1948) in his New discoveries in Babylonia about Genesis (1936). The book was republished by Wiseman's son, Donald Wiseman, as Ancient records and the structure of Genesis: A case for literary unity in 1985. The hypothesis received some support from R. K. Harrison (1969) but otherwise remained without acceptance in scholarly circles. == History == === P. J. Wiseman === Air Commodore P. J. Wiseman, a British officer who visited many active archaeological sites during his career in the Middle East, found that ancient narrative tablets usually ended in colophons which had a very specific format consisting of three parts: 1) "this has been the history/book/genealogy of..."; 2) the name of the person who wrote or owned the tablet; and 3) a date (such as "in the year of the great earthquake" or "the 3rd year of king so-and-so", etc.). Wiseman noted that there are 11 phrases in Genesis which have the same colophon format, which have


id: wiseman-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Wiseman_hypothesis-1.md
category: reference
title: Wiseman hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wiseman_hypothesis
date_saved: 2026-05-05T10:00:43.966901+00:00
instance: kb-cron
parent: wiseman-hypothesis-20260505-0
summary:
== See also == Mosaic authorship Documentary hypothesis Lower criticism Biblical criticism Dating the Bible == Footnotes == == References == Hamilton, Victor (1990). The Book of Genesis (New International Commentary on the Old Testament Series) 1-17. Grand Rapids: W.B. Eerdmans. ISBN 0-8028-2521-4. Harrison, R.K. (1969). Introduction to the Old Testament. Grand Rapids: Eerdmans. ISBN 978-0-8028-3107-1. Hunger, H. (1968). Babylonische und Assyrische Kolophone (Volume 2 of Alter Orient und Altes Testament). Verlag Butzon & Bercker. Leichty, E. (June 7, 1964). "The Colophon". In Biggs, Robert D.; Brinkman, J A (eds.). Studies Presented to A. Leo Oppenheim: 1964. Chicago: University of Chicago Press. pp. 147–54. Walvoord, John; Zuck, R.B; Baker, Walter L.; Blaising, C. A. (1985). Bible Knowledge Commentary: Old Testament. Colorado Springs: Victor. ISBN 0-88207-813-5. Wiseman, P. J (1958). Creation Revealed in Six Days: The evidence of Scripture confirmed by Archaeology. London: Marshall, Morgan and Scott. Wolf, Herbert (2007). An Introduction to the Old Testament Pentateuch. Chicago: Moody Publishers. ISBN 978-0-8024-4156-0. == Further reading == Harrison, R.K. (June 1994). "From Adam To Noah: A Reconsideration Of The Antediluvian Patriarchs' Ages" (PDF). Journal of the Evangelical Theological Society. 37 (2): 161–168. Hamilton, Donald L., Homiletical Handbook, p. 141, Broadman and Holmann


id: wood-pasture-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-0.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
The wood-pasture hypothesis (also known as the Vera hypothesis and the megaherbivore theory) is a scientific hypothesis positing that open and semi-open pastures and wood-pastures formed the predominant type of landscape in post-glacial temperate Europe, rather than the common belief of primeval forests. The hypothesis proposes that such a landscape would be formed and maintained by large wild herbivores. Although others, including landscape ecologist Oliver Rackham, had previously expressed similar ideas, it was the Dutch researcher Frans Vera, who, in his 2000 book Grazing Ecology and Forest History, first developed a comprehensive framework for such ideas and formulated them into a theory. Vera's proposals, although controversial, came at a time when the role grazers played in woodlands was increasingly being reconsidered, and are credited for ushering in a period of increased reassessment and interdisciplinary research in European conservation theory and practice. Although Vera largely focused his research on the European situation, his findings could also be applied to other temperate ecological regions worldwide, especially the broadleaved ones. Vera's ideas have met with both rejection and approval in the scientific community, and continue to lay an important foundation for the rewilding-movement. While his proposals for widespread semi-open savanna as the predominant


id: wood-pasture-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-1.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
=== The reconstruction of vegetation history === Apart from theoretical considerations, this concept has relied and continues to rely heavily on both field observations and, more recently, on findings from pollen analysis, which allow inferences about the vegetation structure of past epochs. For example, vegetation trends can be reconstructed from the ratio of tree pollen to pollen associated with grassland. Pollen analysis is the most widely used means of generating historic vegetation data and the analysis of pollen data has provided a solid database from which a predominance of forest throughout the early stages of the Holocene of temperate Europe, especially the Atlantic, is generally inferred, although the possibility of regional differences remains open. On that basis, the history of vegetation in Europe is generally reconstructed as a history of forest. Pollen analysis, however, has been criticized for its inherent bias towards wind-pollinated plant species and, importantly, wind-pollinated trees, and has been shown to overestimate forest cover. To account for this bias, a corrective model (REVEALS) is used, whose application leads to results that differ substantially from those drawn from the traditional comparison of pollen percentages alone. Alternatively to or in combination with pollen, fossil indicator organisms – such as


id: wood-pasture-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-2.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
==== Background: grazers and browsers ==== The impact herbivores have on the landscape level depends on their way of feeding. Namely, browsers like roe deer, elk and the black rhino focus on woody vegetation, while the diet of grazers like horse, cattle and the white rhino is dominated by grasses and forbs. Intermediate feeders, like the wisent and the red deer, fall in between. Generally, grazers tend to be more social, less selective in their food choices and forage more intensively. Therefore, their impact on vegetation composition tends to be higher, as well as their ability to maintain open spaces. Since the extinction of the aurochs in 1627 and the wild horse around 1900, none of the remaining large wild herbivores in Europe is an obligate grazer. Similarly, domesticated descendants of aurochs and wild horse, cattle and horse, are now largely kept in stables, factory farms and close to settlements, making them effectively extinct in the landscape. What remains are browsers and mixed feeders – roe deer, red deer, elk, wild boar, wisent and beaver, often in low densities. Backbreeding-projects, such as the German Taurus project and the Dutch Tauros programme are addressing this issue by breeding domestic cattle that


id: wood-pasture-hypothesis-20260505-3
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-3.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
Vera relies on several lines of argument based on experiments, ecology, evolutionary ecology, palynology, history and etymology. One of his main arguments is of an ecological nature; the widespread lack of successful regeneration of light-demanding tree species in modern forests. Especially the lack of regeneration of pedunculate oak, sessile oak (together hereafter addressed as "oak") and common hazel in Europe. He contrasts this reality with European pollen deposits from previous ages, where oak and hazel often form a dominant amount of pollen, making a dominance of these species in previous ages conceivable. Especially in regard to hazel, sufficient flowering is only achieved when enough sunlight is available, i.e. the plant grows outside of a closed canopy. He argues that the only explanation for the great abundance of oak and hazel pollen in previous ages is that the primeval landscape was open, and this contrast forms the principal theorem of his hypothesis. It has also been suggested that oak requires disturbances for successful establishment, disturbance large herbivores may provide. However, pollen records from islands that lacked many of the large grazers and browsers that, according to Vera, were essential for the maintenance of landscapes with an open character in temperate Europe


id: wood-pasture-hypothesis-20260505-4
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-4.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
==== Circular reasoning ==== Vera stressed that the prevailing high-forest theory was born out of observations of spontaneous regeneration in the absence of grazing animals. He argued that the presupposition that these animals do not exert a significant influence on natural regeneration, and thus on the vegetation structure as a whole, has been made without comparative confirmation, and is therefore a circular argument. Indeed, modern forestry and forest theory arose largely in the modern era and went hand in hand with the ongoing inclosure of common land throughout Europe. A consequence thereof was in many cases a ban of livestock from the forests, which had previously largely been open woodland pastures, often dominated by oaks. These were multifunctional and used for a range of purposes, from pannage and livestock grazing to the harvest of tree hay, coppice, timber and oak galls for the manufacture of ink, as well as for the production of charcoal, crops and fruit. This former usage of forests is often still revealed by a big age gap between tree generations, particularly if the oldest trees are mainly oaks, and many Central European forest reserves originated as common wood-pastures. ==== Shifted baselines ==== In nature conservation, a


id: wood-pasture-hypothesis-20260505-5
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-5.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
Vera pointed out that words like wold and forest used to have different connotations than they do today. While today, a forest is a dense and reasonably large tract of trees, the medieval Latin forestis, from which it derives, assigned open stands of trees, and was a wild and uncultivated land home also to aurochs and wild horses. According to historical sources, these forestis included hawthorn, blackthorn, wild cherry, wild apple and wild pear, as well as oaks, all of which are light-demanding species that cannot regenerate successfully in closed-canopy forest. From this Vera concluded that original wildwoods still existed in Europe during the Medieval period. Thus, when scholars of the 19th and 20th century assumed that grazing animals had destroyed the original European closed-canopy wildwoods, they were misinterpreting these terms. Instead, these forests, he found, had been destroyed following the industrial revolution and the population growth it caused, which in turn caused overexploitation. He further argued that from this initial misinterpretation gave rise to another misinterpretation: that forest regeneration would naturally take place inside the forest. Thus, scholars of the 19th and 20th century such as Elias Landolt (forester) interpreted medieval grazing regulations to allow tree regeneration in coppiced


id: wood-pasture-hypothesis-20260505-6
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-6.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
==== Associational resistance ==== The term associational resistance describes facilitating relationships between plants that grow close to each other, against both biotic and abiotic stresses like browsing, drought, or salinity. In relation to grazed ecosystems, it can allow for the recruitment of trees and other palatable woody species, via thorny nurse bushes, in these environments. It has been proposed and demonstrated that associational resistance can be a key process in grazed environments, ensuring natural succession.In temperate Europe, succession on pastures commonly starts with so called "islets" ("Geilstellen"), patches of dung which are avoided by the herbivores for an amount of time after deposition, sufficient to allow the establishment of relatively unpalatable species such as rushes, nettles and hummocks of tall grasses like tussock grass. These swards, in turn, provide protection for thorny shrubs such as blackthorn, roses, hawthorn, juniper, bramble, holly and barberry during their early years, when they do not yet have protective thorns and are therefore vulnerable. Once the thorny saplings are fully established, they grow bigger over time and subsequently allow other, less resilient species to establish in their thorn protection, forming mantle and fringe vegetation together with species such as guelder rose, wild privet and dogwood.


id: wood-pasture-hypothesis-20260505-7
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-7.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
Although Vera himself limited his argument to the Holocene and the fauna present into historical times, research better supports his claims in regard to earlier interglacials. Modern humans have likely exerted a strong influence in Europe since their first appearance here during the Weichselian glaciation, which has led some researchers to criticize Vera's choice of the early to mid Holocene as his benchmark for pristine nature. Instead, they argue that pristine nature only existed in Europe before the entering of Homo sapiens. They argue that the best model for what a truly natural landscape during a warm period in Europe would look like is the Eemian interglacial, which was the last warm period before the current Holocene, approximately 130,000 to 115,000 years ago, and the last warm period before Homo sapiens. While archaic humans existed in the form of neanderthals, their influence was probably only localised, due to their low population density. During this warm period, paleoecological data indeed suggest that semi-open landscapes, as postulated by Vera, were widespread and common, most likely maintained by large herbivores. Next to these semi-open landscapes, however, the researchers also found evidence for closed-canopy forest. Overall, the Eemian landscape appears to have been very


id: wood-pasture-hypothesis-20260505-8
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-8.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
The effects of the global extinction of megafauna are likely to have been far-reaching and damaging to ecosystems, and continue to be. The late Quaternary extinction event is unprecedented in the Cenozoic (i.e. since the extinction of the non-avian dinosaurs) in its selectivity for large animals. Accordingly, the modern European megafauna-extirpated ecosystems deviate strongly from the megafauna-rich evolutionary norm. Similar to how herds of herbivores like wildebeest, zebra, impala, buffalo, and elephants drive African savanna vegetation patterns, and not vice versa (i.e. the vegetation dictates the activities of these herbivores), it now seems likely that herbivore herds could have provided similar ecosystem functions in the temperate regions before the Quaternary extinctions. In Europe, where many species such as the straight-tusked elephant, two species of Stephanorhinus and the hippopotamus among many others were lost, this meant that their ecosystem functions – such as plant matter consumption and seed dispersal – were lost as well. Without the disturbance these animals provide, it is argued, forests could develop unhindered and landscapes became more uniform. As this is detrimental to species adapted to the presence of megafauna, some scholars advocate for the reintroduction of these animals where possible, or the introduction of modern proxy


id: wood-pasture-hypothesis-20260505-9
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-9.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
The logical consequence of this was that species associated with grasslands, forest fringes and old, open-grown trees disappeared on large scale, since many ecosystems in Europe, including highly species-rich grasslands in Romania, strictly depend on some management and are negatively impacted if the areas are left fallow and overgrown by forest vegetation. Similarly, the displacement of aspen in boreal forests seems to be accelerated more because of increasing competition in the increasingly closed stands than via browsing. In Europe, grasslands were maintained by large herbivores over the last 1,8 million years, resulting in an exceptional diversity of species in many European grasslands. For example, on a wooded meadow in Estonia, 76 species of plant per 1 square metre (11 sq ft) were counted in 2000, making it one of the world's record sites. Similarly high numbers were counted at other locations in Eastern Europe, making the region one of the hotspots for plant species richness on small scale worldwide. However, grasslands in Europe and elsewhere are increasingly under threat, including from forest encroachment following abandonment, ill-conceived forest restoration schemes, overgrazing and agricultural intensification. Especially the notion that most grasslands derive from human management and as such are essentially degraded former


id: wood-pasture-hypothesis-20260505-10
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-10.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
Grazed woodlands, wood-pastures and pastures in Europe harbour high biodiversity. Rare perennial plant species commonly or exclusively associated with these ecosystems in Europe include hellebores, peonies, asphodels, dittany, black false hellebore and bastard balm. The tree layer is often dominated by a number of oak species and many rare, local and threatened species such as Florentine wild apple, Lebanese wild apple, medlar, sorb tree, pears and wild plums are more often found in European silvopastoral systems than in commercial forest. Rare or declining bird species such as the European roller, hoopoe, several species of shrike, owls (scops owl, little owl) as well as wrynecks and middle spotted woodpeckers are attracted by wood-pastures in particular. In Iberia, the semi-natural oak-woodlands known as dehesa/montado are home to endemic species such as the Spanish imperial eagle and the Iberian lynx. Wood-pastures also provide important habitat for many species of invertebrates. Due to the abundance of large, old trees, wood-pastures are especially important for saproxylic beetles. This includes spectacular and rare species such as capricorn beetle, stag beetles (such as Lucanus cervus), variable chafer and click beetles. In the British Isles alone nearly 1800 species of invertebrates depend on decaying wood, including 700 species


id: wood-pasture-hypothesis-20260505-11
file: data/en.wikipedia.org/wiki/Wood-pasture_hypothesis-11.md
category: reference
title: Wood-pasture hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood-pasture_hypothesis
date_saved: 2026-05-05T10:00:45.187316+00:00
instance: kb-cron
parent: wood-pasture-hypothesis-20260505-0
summary:
== Further reading == Bunzel-Drüke, Margret; Luick, Rainer (2024): "Master builders of biodiversity". Naturschutz und Landschaftsplanung. Jepson, Paul and Blythe, Cain (2020). Rewilding: The Radical New Science of Ecological Recovery, Icon Books Ltd. ISBN 978-1-78578-627-3 Hodder, K.H.; Bullock, J.M.; Buckland, P.C.; Kirby, K.J. (2005). Large Herbivores in the Wildwood and in modern naturalistic grazing systems (Report). English Nature. Kirby, K.J. (May 2004). "A model of a natural wooded landscape in Britain as influenced by large herbivore activity". Forestry. 77 (5): 405–420. doi:10.1093/forestry/77.5.405. Marris, Emma (2011). Rambunctious garden: saving nature in a post-wild world (1st U.S. ed.). New York: Bloomsbury. ISBN 978-1-60819-032-4. OCLC 639161286. Reif, Albert; Gärtner, Stefanie (December 2007). "Die natürliche Verjüngung der laubabwerfenden Eichen-arten Stieleiche (Quercus robur L.) und Traubeneiche (Quercus petraea Liebl.) – eine Literaturstudie mit besonderer Berücksichtigung der Waldweide" (PDF). Waldoekologie Online (in German). Rotherham, Ian D., ed. (2013). Trees, forested landscapes, and grazing animals: a European perspective on woodlands and grazed treescapes. Abingdon, Oxon: Routledge. ISBN 978-0-415-62611-8. OCLC 829911159. Smith, David; Whitehouse, Nicki; Bunting, M. Jane; Chapman, Henry (March 2010). "Can we characterise 'openness' in the Holocene palaeoenvironmental record? Modern analogue studies of insect faunas and pollen spectra from Dunham Massey deer park and Epping Forest,


id: working-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Working_hypothesis-0.md
category: reference
title: Working hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Working_hypothesis
date_saved: 2026-05-05T10:00:46.409821+00:00
instance: kb-cron
parent: working-hypothesis-20260505-0
summary:
A working hypothesis is a hypothesis that is provisionally accepted as a basis for further ongoing research in the hope that a tenable theory will be produced, even if the hypothesis ultimately fails. Like all hypotheses, a working hypothesis is constructed as a statement of expectations, which can be linked to deductive, exploratory research in empirical investigation and is often used as a conceptual framework in qualitative research. The term "working" indicates that the hypothesis is subject to change. == History == Use of the phrase "working hypothesis" goes back to at least the 1850s. Charles Sanders Peirce came to hold that an explanatory hypothesis is not only justifiable as a tentative conclusion by its plausibility (by which he meant its naturalness and economy of explanation), but also justifiable as a starting point by the broader promise that the hypothesis holds for research. This idea of justifying a hypothesis as potentially fruitful (at the level of research method), not merely as plausible (at the level of logical conclusions), is essential for the idea of a working hypothesis, as later elaborated by Peirce's fellow pragmatist John Dewey. In 1890, and again in 1897, Thomas Chrowder Chamberlin wrote "The method of multiple


id: working-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Working_hypothesis-1.md
category: reference
title: Working hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Working_hypothesis
date_saved: 2026-05-05T10:00:46.409821+00:00
instance: kb-cron
parent: working-hypothesis-20260505-0
summary:
Given its success (the working hypothesis), he (the social scientist) may restate his world from this standpoint and get the basis for further investigation that again always takes the form of a problem. The solution of this problem is found over again in the possibility of fitting his hypothetical proposition into the whole within which it arises. And he must recognize that this statement is only a working hypothesis at the best, i.e., he knows that further investigation will show that the former statement of his world is only provisionally true, and must be false from the standpoint of a larger knowledge, as every partial truth is necessarily false over against the fuller knowledge which he will gain later (p. 370). For Putnam, the working hypothesis represents a practical starting point in the design of an empirical research exploration. A contrasting example of this conception of the working hypothesis is illustrated by the brain-in-a-vat thought experiment. This experiment involves confronting the global skeptic position that we, in fact, are all just brains in vats being stimulated by a mad scientist to believe that our reality is real. Putnam argued that this proposition, however, rests on a "magical theory of reference"


id: yamatai-honshu-theory-20260505-0
file: data/en.wikipedia.org/wiki/Yamatai_Honshu_Theory-0.md
category: reference
title: Yamatai Honshu Theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Yamatai_Honshu_Theory
date_saved: 2026-05-05T10:00:47.586257+00:00
instance: kb-cron
parent: yamatai-honshu-theory-20260505-0
summary:
The Yamatai Honshu Theory is the theory that the Yamatai-koku was located in Honshu, specifically Kinai (now Kinki region), where the capital was located in the Kofun period rather than in Kyushu as the Yamatai Kyushu Theory proposes. According to this theory, the Yamatai-koku was essentially continuous with the Yamato Kingship, with its capital in roughly the same region, and the Yamatai-koku transformed into the Yamato Kingship when the Kofun period began. == Overview == In the Edo period, Arai Hakuseki advocated the theory in which he insisted Yamatai-koku was located in the Yamato Province (大和国, Nara prefecture, Honshu). Later, he advocated the different theory, in which he insisted Yamatai-koku was located in the Yamato county (山門郡, Yamato-gun) in the Chikugo Province (Fukuoka prefecture, Kyushu) in his book Foreign Affairs Chronicle. Since then, from the Edo period to the present, the mainstream of the academic world has been largely divided between the "Yamatai Honshu (Kinai) Theory (邪馬台国畿内説)", which has been insisted and supported by Naito Konan et al. and the "Yamatai Kyushu Theory (邪馬台国九州説)", which has been insisted and supported by Shiratori Kurakichi et al. The Kyushu theory, however, is divided into two distinct theories: one that says the Yamataikoku


id: yamatai-kyushu-theory-20260505-0
file: data/en.wikipedia.org/wiki/Yamatai_Kyushu_Theory-0.md
category: reference
title: Yamatai Kyushu Theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Yamatai_Kyushu_Theory
date_saved: 2026-05-05T10:00:48.743589+00:00
instance: kb-cron
parent: yamatai-kyushu-theory-20260505-0
summary:
The Yamatai Kyushu Theory is the theory that the Yamatai kingdom was located in Kyushu rather than in Honshu as the Yamatai Honshu Theory proposes. The theory proposes that the original capital of Japan was located in Kyushu, and when the Kofun period began, the Yamato Kingship moved the capital east to the Kinai region, first in the Yamato Province (Nara prefecture), then Kyoto in the Yamashiro Province (Kyoto Prefecture). == Overview == In the Edo period, Arai Hakuseki adovocated the "Kinai Yamataikoku theory" which says Yamatai-koku was located in 大和 (Yamato Province, ie. Nara prefecture) in the Kinai, Honshu. Later, Arai advocated a different theory, the "Kyūshū Yamataikoku theory" which says Yamatai-koku was located in "Yamato county (山門-郡, Yamato-gun)" in Chikugo Province (Fukuoka prefecture, Northern Kyushu) in his "Foreign Affairs Record". Since then, the mainstream of academic circles has been divided into two major theories: the "Honshu theory" (by Naitō Torajirō et al.) holds that Yamatai-koku was located in Honshu. the "Kyushu theory" (by Shiratori Kurakichi et al.) holds that Yamatai-koku was located in Kyushu. The Kyūshū theory has itself been divided into two schools. One school insists the "Kyushu Yamatai-koku" moved to the East and became the Imperial


id: zoo-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Zoo_hypothesis-0.md
category: reference
title: Zoo hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Zoo_hypothesis
date_saved: 2026-05-05T10:00:49.963140+00:00
instance: kb-cron
parent: zoo-hypothesis-20260505-0
summary:
The zoo hypothesis speculates on the assumed behavior and existence of technologically advanced extraterrestrial life and the reasons they refrain from contacting Earth. It is one of many theoretical explanations for the Fermi paradox. The hypothesis states that extraterrestrial life intentionally avoids communication with Earth to allow for natural evolution and sociocultural development, and avoiding interplanetary contamination, similar to people observing animals at a zoo. The hypothesis seeks to explain the apparent absence of extraterrestrial life despite its generally accepted plausibility and hence the reasonable expectation of its existence. Extraterrestrial life forms might, for example, choose to allow contact once the human species has passed certain technological, political, and/or ethical standards. Alternatively, they may withhold contact until humans force contact upon them, possibly by sending a spacecraft to an extraterrestrial-inhabited planet. In this regard, reluctance to initiate contact could reflect a sensible desire to minimize risk. An extraterrestrial society with advanced remote-sensing technologies may conclude that direct contact with neighbors confers added risks to itself without an added benefit. A variant on the zoo hypothesis suggested by former MIT Haystack Observatory scientist John Allen Ball is the "laboratory" hypothesis, in which humanity is being subjected to experiments, with Earth serving


id: zoo-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Zoo_hypothesis-1.md
category: reference
title: Zoo hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Zoo_hypothesis
date_saved: 2026-05-05T10:00:49.963140+00:00
instance: kb-cron
parent: zoo-hypothesis-20260505-0
summary:
A modified zoo hypothesis is a possible solution to the Fermi paradox. The time between the emergence of the first civilization within the Milky Way and all subsequent civilizations could be enormous. Monte Carlo simulation shows the first few inter-arrival times between emergent civilizations would be similar in length to geologic epochs on Earth. The zoo hypothesis assumes a civilization may have a ten-million, one-hundred-million, or half-billion-year head start on humanity, i.e., it may have the capability to completely negate our best attempts to detect it. The zoo hypothesis relies in part on applying the concept of hegemonic power to the Fermi paradox. Even if a first hegemonic non-interventionist grand civilization (first civilization) is long gone, their initial legacy could persist in the form of a passed-down tradition, or perhaps in an artificial lifeform (artificial superintelligence) dedicated to a non-interventionist hegemonic goal without the risk of death. Thus, the hegemonic power does not even have to be the first civilization, but simply the first to spread its non-interventionist doctrine and control over a large volume of the galaxy. If just one civilization acquired hegemony in the distant past, it could form an unbroken chain of taboo against rapacious colonization in


id: scientific-modelling-20260505-0
file: data/en.wikipedia.org/wiki/Scientific_modelling-0.md
category: reference
title: Scientific modelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Scientific_modelling
date_saved: 2026-05-05T10:00:52.576146+00:00
instance: kb-cron
parent: scientific-modelling-20260505-0
summary:
Scientific modelling is an activity that produces models representing empirical objects, phenomena, and physical processes, to make a particular part or feature of the world easier to understand, define, quantify, visualize, or simulate. It requires selecting and identifying relevant aspects of a situation in the real world and then developing a model to replicate a system with those features. Different types of models may be used for different purposes, such as conceptual models to better understand, operational models to operationalize, mathematical models to quantify, computational models to simulate, and graphical models to visualize the subject. Modelling is an essential and inseparable part of many scientific disciplines, each of which has its own ideas about specific types of modelling. The following was said by John von Neumann. ... the sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work—that is, correctly to describe phenomena from a reasonably wide area. There is also an increasing attention to scientific modelling in


id: scientific-modelling-20260505-1
file: data/en.wikipedia.org/wiki/Scientific_modelling-1.md
category: reference
title: Scientific modelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Scientific_modelling
date_saved: 2026-05-05T10:00:52.576146+00:00
instance: kb-cron
parent: scientific-modelling-20260505-0
summary:
=== Systems === A system is a set of interacting or interdependent entities, real or abstract, forming an integrated whole. In general, a system is a construct or collection of different elements that together can produce results not obtainable by the elements alone. The concept of an 'integrated whole' can also be stated in terms of a system embodying a set of relationships which are differentiated from relationships of the set to other elements, and form relationships between an element of the set and elements not a part of the relational regime. There are two types of system models: 1) discrete in which the variables change instantaneously at separate points in time and, 2) continuous where the state variables change continuously with respect to time. === Generating a model === Modelling is the process of generating a model as a conceptual representation of some phenomenon. Typically a model will deal with only some aspects of the phenomenon in question, and two models of the same phenomenon may be essentially different—that is to say, that the differences between them comprise more than just a simple renaming of components. Such differences may be due to differing requirements of the model's end users,


id: scientific-modelling-20260505-2
file: data/en.wikipedia.org/wiki/Scientific_modelling-2.md
category: reference
title: Scientific modelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Scientific_modelling
date_saved: 2026-05-05T10:00:52.576146+00:00
instance: kb-cron
parent: scientific-modelling-20260505-0
summary:
Rainer Hegselmann, Ulrich Müller and Klaus Troitzsch (eds.) (1996). Modelling and Simulation in the Social Sciences from the Philosophy of Science Point of View. Theory and Decision Library. Dordrecht: Kluwer. Paul Humphreys (2004). Extending Ourselves: Computational Science, Empiricism, and Scientific Method. Oxford: Oxford University Press. Johannes Lenhard, Günter Küppers and Terry Shinn (Eds.) (2006) "Simulation: Pragmatic Constructions of Reality", Springer Berlin. Tom Ritchey (2012). "Outline for a Morphology of Modelling Methods: Contribution to a General Theory of Modelling". In: Acta Morphologica Generalis, Vol 1. No 1. pp. 1–20. William Silvert (2001). "Modelling as a Discipline". In: Int. J. General Systems. Vol. 30(3), pp. 261. Sergio Sismondo and Snait Gissis (eds.) (1999). Modeling and Simulation. Special Issue of Science in Context 12. Eric Winsberg (2018) "Philosophy and Climate Science" Cambridge: Cambridge University Press Eric Winsberg (2010) "Science in the Age of Computer Simulation" Chicago: University of Chicago Press Eric Winsberg (2003). "Simulated Experiments: Methodology for a Virtual World". In: Philosophy of Science 70: 105–125. Tomáš Helikar, Jim A Rogers (2009). "ChemChains Archived 2021-03-03 at the Wayback Machine: a platform for simulation and analysis of biochemical networks aimed to laboratory scientists". BioMed Central. == External links == Models. Entry in the Internet


id: enterprise-modelling-20260505-0
file: data/en.wikipedia.org/wiki/Enterprise_modelling-0.md
category: reference
title: Enterprise modelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Enterprise_modelling
date_saved: 2026-05-05T10:00:53.796573+00:00
instance: kb-cron
parent: enterprise-modelling-20260505-0
summary:
Enterprise modelling is the abstract representation, description and definition of the structure, processes, information and resources of an identifiable business, government body, or other large organization. It deals with the process of understanding an organization and improving its performance through creation and analysis of enterprise models. This includes the modelling of the relevant business domain (usually relatively stable), business processes (usually more volatile), and uses of information technology within the business domain and its processes. == Overview == Enterprise modelling is the process of building models of whole or part of an enterprise with process models, data models, resource models and/or new ontologies etc. It is based on knowledge about the enterprise, previous models and/or reference models as well as domain ontologies using model representation languages. An enterprise in general is a unit of economic organization or activity. These activities are required to develop and deliver products and/or services to a customer. An enterprise includes a number of functions and operations such as purchasing, manufacturing, marketing, finance, engineering, and research and development. The enterprise of interest are those corporate functions and operations necessary to manufacture current and potential future variants of a product. The term "enterprise model" is used in


id: enterprise-modelling-20260505-1
file: data/en.wikipedia.org/wiki/Enterprise_modelling-1.md
category: reference
title: Enterprise modelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Enterprise_modelling
date_saved: 2026-05-05T10:00:53.796573+00:00
instance: kb-cron
parent: enterprise-modelling-20260505-0
summary:
=== Enterprise model === An enterprise model is a representation of the structure, activities, processes, information, resources, people, behavior, goals, and constraints of a business, government, or other enterprises. Thomas Naylor (1970) defined a (simulation) model as "an attempt to describe the interrelationships among a corporation's financial, marketing, and production activities in terms of a set of mathematical and logical relationships which are programmed into the computer." These interrelationships should according to Gershefski (1971) represent in detail all aspects of the firm including "the physical operations of the company, the accounting and financial practices followed, and the response to investment in key areas" Programming the modelled relationships into the computer is not always necessary: enterprise models, under different names, have existed for centuries and were described, for example, by Adam Smith, Walter Bagehot, and many others. According to Fox and Gruninger (1998) from "a design perspective, an enterprise model should provide the language used to explicitly define an enterprise... From an operations perspective, the enterprise model must be able to represent what is planned, what might happen, and what has happened. It must supply the information and knowledge necessary to support the operations of the enterprise, whether they be performed


id: enterprise-modelling-20260505-2
file: data/en.wikipedia.org/wiki/Enterprise_modelling-2.md
category: reference
title: Enterprise modelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Enterprise_modelling
date_saved: 2026-05-05T10:00:53.796573+00:00
instance: kb-cron
parent: enterprise-modelling-20260505-0
summary:
== Enterprise engineering == Enterprise engineering is the discipline concerning the design and the engineering of enterprises, regarding both their business and organization. In theory and practice two types of enterprise engineering has emerged. A more general connected to engineering and the management of enterprises, and a more specific related to software engineering, enterprise modelling and enterprise architecture. In the field of engineering a more general enterprise engineering emerged, defined as the application of engineering principals to the management of enterprises. It encompasses the application of knowledge, principles, and disciplines related to the analysis, design, implementation and operation of all elements associated with an enterprise. In essence this is an interdisciplinary field which combines systems engineering and strategic management as it seeks to engineer the entire enterprise in terms of the products, processes and business operations. The view is one of continuous improvement and continued adaptation as firms, processes and markets develop along their life cycles. This total systems approach encompasses the traditional areas of research and development, product design, operations and manufacturing as well as information systems and strategic management. This fields is related to engineering management, operations management, service management and systems engineering. In the context of software


id: human-performance-modeling-20260505-0
file: data/en.wikipedia.org/wiki/Human_performance_modeling-0.md
category: reference
title: Human performance modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Human_performance_modeling
date_saved: 2026-05-05T10:00:54.973981+00:00
instance: kb-cron
parent: human-performance-modeling-20260505-0
summary:
Human performance modeling (HPM) is a method of quantifying human behavior, cognition, and processes. It is a tool used by human factors researchers and practitioners for both the analysis of human function and for the development of systems designed for optimal user experience and interaction . It is a complementary approach to other usability testing methods for evaluating the impact of interface features on operator performance. == History == The Human Factors and Ergonomics Society (HFES) formed the Human Performance Modeling Technical Group in 2004. Although a recent discipline, human factors practitioners have been constructing and applying models of human performance since World War II. Notable early examples of human performance models include Paul Fitts' model of aimed motor movement (1954), the choice reaction time models of Hick (1952) and Hyman (1953), and the Swets et al. (1964) work on signal detection. It is suggested that the earliest developments in HPM arose out of the need to quantify human-system feedback for those military systems in development during WWII (see Manual Control Theory below), with continued interest in the development of these models augmented by the cognitive revolution (see Cognition & Memory below). == Human Performance Models == Human performance models


id: human-performance-modeling-20260505-1
file: data/en.wikipedia.org/wiki/Human_performance_modeling-1.md
category: reference
title: Human performance modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Human_performance_modeling
date_saved: 2026-05-05T10:00:54.973981+00:00
instance: kb-cron
parent: human-performance-modeling-20260505-0
summary:
==== Manual Control Theory ==== Complex motor tasks, such as those carried out by musicians and athletes, are not well modeled due to their complexity. Human target-tracking behavior, however, is one complex motor task that is an example of successful HPM. The history of manual control theory is extensive, dating back to the 1800s in regard to the control of water clocks. However, during the 1940s with the innovation of servomechanisms in WWII, extensive research was put into the continuous control and stabilization of contemporary systems such as radar antennas, gun turrets, and ships/aircraft via feedback control signals. Analysis methods were developed that predicted the required control systems needed to enable stable, efficient control of these systems (James, Nichols, & Phillips, 1947). Originally interested in temporal response - the relationship between sensed output and motor output as a function of time - James et al. (1947) discovered that the properties of such systems are best characterized by understanding temporal response after it had been transformed into a frequency response; a ratio of output to input amplitude and lag in response over the range of frequencies to which they are sensitive. For systems that respond linearly to these inputs, the frequency


id: human-performance-modeling-20260505-2
file: data/en.wikipedia.org/wiki/Human_performance_modeling-2.md
category: reference
title: Human performance modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Human_performance_modeling
date_saved: 2026-05-05T10:00:54.973981+00:00
instance: kb-cron
parent: human-performance-modeling-20260505-0
summary:
==== Visual Sampling ==== Many domains contain multiple displays, and require more than a simple discrete yes/no response time measurement. A critical question for these situations may be "How much time will operators spend looking at X relative to Y?" or "What is the likelihood that the operator will completely miss seeing a critical event?" Visual sampling is the primary means of obtaining information from the world. An early model in this domain is Sender's (1964, 1983) based upon operators monitoring of multiple dials, each with different rates of change. Operators try, as best as they can, to reconstruct the original set of dials based on discrete sampling. This relies on the mathematical Nyquist theorem stating that a signal at W Hz can be reconstructed by sampling every 1/W seconds. This was combined with a measure of the information generation rate for each signal, to predict the optimal sampling rate and dwell time for each dial. Human limitations prevent human performance from matching optimal performance, but the predictive power of the model influenced future work in this area, such as Sheridan's (1970) extension of the model with considerations of access cost and information sample value. A modern conceptualization by Wickens


id: human-performance-modeling-20260505-3
file: data/en.wikipedia.org/wiki/Human_performance_modeling-3.md
category: reference
title: Human performance modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Human_performance_modeling
date_saved: 2026-05-05T10:00:54.973981+00:00
instance: kb-cron
parent: human-performance-modeling-20260505-0
summary:
==== Workload ==== Although an exact definition or method for measurement of the construct of workload is debated by the human factors community, a critical part of the notion is that human operators have some capacity limitations and that such limitations can be exceeded only at the risk of degrading performance. For physical workload, it may be understood that there is a maximum amount that a person should be asked to lift repeatedly, for example. However, the notion of workload becomes more contentious when the capacity to be exceeded is in regard to attention - what are the limits of human attention, and what exactly is meant by attention? Human performance modeling produces valuable insights into this area. Byrne and Pew (2009) consider an example of a basic workload question: "To what extent do task A and B interfere?" These researchers indicate this as the basis for the psychological refractory period (PRP) paradigm. Participants perform two choice reaction-time tasks, and the two tasks will interfere to a degree - especially when the participant must react to the stimuli for the two tasks when they are close together in time - but the degree of interference is typically smaller than the


id: human-performance-modeling-20260505-4
file: data/en.wikipedia.org/wiki/Human_performance_modeling-4.md
category: reference
title: Human performance modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Human_performance_modeling
date_saved: 2026-05-05T10:00:54.973981+00:00
instance: kb-cron
parent: human-performance-modeling-20260505-0
summary:
==== Routine Cognitive Skill ==== One area of memory and cognition regards modeling routine cognitive skills; when an operator has the correct knowledge of how to perform a task and simply needs to execute that knowledge. This is widely applicable, as many operators are practiced enough that their procedures become routine. The GOMS (goals, operators, methods, and selection rules) family of Human Performance Models popularized and well-defined by researchers in the field (Card et al., 1983; John & Kieras, 1996a, 1996b) were originally applied to model users of computer interfaces, but have since been extended to other areas. They are useful HPM tools, suitable for a variety of different concerns and sizes of analysis, but are limited in regard to analyzing user error (see Wood & Kieras, 2002, for an effort to extend GOMS to handling errors). The simplest form of a GOMS model is a keystroke-level model (KLM) - in which all physical actions are listed (e.g., keystrokes, mouse clicks), also termed operations, that a user must take in order to complete a given task. Mental operations (e.g., find an object on the screen) augment this using a straightforward set of rules. Each operations has a time associated with


id: human-performance-modeling-20260505-5
file: data/en.wikipedia.org/wiki/Human_performance_modeling-5.md
category: reference
title: Human performance modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Human_performance_modeling
date_saved: 2026-05-05T10:00:54.973981+00:00
instance: kb-cron
parent: human-performance-modeling-20260505-0
summary:
=== Integrated Models === Many of these models described are very limited in their application. Although many extensions of SDT have been proposed to cover a variety of other judgement domains (see T.D. Wickens, 2002, for examples), most of these never caught on, and SDT remains limited to binary situations. The narrow scope of these models is not limited to human factors, however - Newton's laws of motion have little predictive power regarding electromagnetism, for example. However, this is frustrating for human factors professionals, because real human performance in vivo draws upon a wide array of human capabilities. As Byrne & Pew (2009) describe, "in the space of a minute, a pilot might quite easily conduct a visual search, aim for and push a button, execute a routine procedure, make a multiple-cue probabilistic judgement" and do just about everything else described by fundamental human performance models. A fundamental review of HPM by the National Academies (Elkind, Card, Hochberg, & Huey, 1990) described integration as the great unsolved challenge in HPM. This issue remains to be solved, however, there have been efforts to integrate and unify multiple models and build systems that span across domains. In human factors, the two primary


id: human-performance-modeling-20260505-6
file: data/en.wikipedia.org/wiki/Human_performance_modeling-6.md
category: reference
title: Human performance modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Human_performance_modeling
date_saved: 2026-05-05T10:00:54.973981+00:00
instance: kb-cron
parent: human-performance-modeling-20260505-0
summary:
==== Cognitive Architectures ==== Cognitive Architectures are broad theories of human cognition based on a wide selection of human empirical data and are generally implemented as computer simulations. They are the embodiment of a scientific hypothesis about those aspects of human cognition relatively constant over time and independent of task (Gray, Young, & Kirschenbaum, 1997; Ritter & young, 2001). Cognitive architectures are an attempt to theoretically unify disconnected empirical phenomena in the form of computer simulation models. While theory is inadequate for the application of human factors, since the 1990s cognitive architectures also include mechanisms for sensation, perception, and action. Two early examples of this include the Executive Process Interactive Control model (EPIC; Kieras, Wood, & Meyer, 1995; Meyer & Kieras, 1997) and the ACT-R (Byrne & Anderson, 1998). A model of a task in a cognitive architecture, generally referred to as a cognitive model, consists of both the architecture and the knowledge to perform the task. This knowledge is acquired through human factors methods including task analyses of the activity being modeled. Cognitive architectures are also connected with a complex simulation of the environment in which the task is to be performed - sometimes, the architecture interacts directly with


id: human-performance-modeling-20260505-7
file: data/en.wikipedia.org/wiki/Human_performance_modeling-7.md
category: reference
title: Human performance modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Human_performance_modeling
date_saved: 2026-05-05T10:00:54.973981+00:00
instance: kb-cron
parent: human-performance-modeling-20260505-0
summary:
=== Misconceptions === Many human performance models share key features with Artificial Intelligence (AI) methods and systems. The function of AI research is to produce systems that exhibit intelligent behavior, generally without consideration of the degree to which that intelligence resembles or predicts human performance, yet the distinction between AI methods and that of HPM is at times unclear. For example, Bayesian classifiers used to filter spam emails approximate human classification performance (classifying spam emails as spam, and non-spam emails as importation) and are thus highly intelligence systems, but fail to rely on interpretation of the semantics of the messages themselves; instead relying on statistical methods. However, Bayesian analysis can also be essential to human performance models. === Usefulness === Models may focus more on the processes involved in human performance rather than the products of human performance, thus limiting their usefulness in human factors practice. === Abstraction === The abstraction necessary for understandable models competes with accuracy. While generality, simplicity, and understandability are important to the application of models in human factors practice, many valuable human performance models are inaccessible to those without graduate, or postdoctoral training. For example, while Fitts's law is straightforward for even undergraduates, the lens


id: integrated-assessment-modelling-20260505-0
file: data/en.wikipedia.org/wiki/Integrated_assessment_modelling-0.md
category: reference
title: Integrated assessment modelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Integrated_assessment_modelling
date_saved: 2026-05-05T10:00:56.130150+00:00
instance: kb-cron
parent: integrated-assessment-modelling-20260505-0
summary:
Integrated assessment modelling (IAM) or integrated modelling (IM) is a term used for a type of scientific modelling that tries to link main features of society and economy with the biosphere and atmosphere into one modelling framework. The goal of integrated assessment modelling is to accommodate informed policy-making, usually in the context of climate change though also in other areas of human and social development. While the detail and extent of integrated disciplines varies strongly per model, all climatic integrated assessment modelling includes economic processes as well as processes producing greenhouse gases. Other integrated assessment models also integrate other aspects of human development such as education, health, infrastructure, and governance. These models are integrated because they span multiple academic disciplines, including economics and climate science and for more comprehensive models also energy systems, land-use change, agriculture, infrastructure, conflict, governance, technology, education, and health. The word assessment comes from the use of these models to provide information for answering policy questions. To quantify these integrated assessment studies, numerical models are used. Integrated assessment modelling does not provide predictions for the future but rather estimates what possible scenarios look like. There are different types of integrated assessment models. One classification distinguishes between


id: integrated-asset-modelling-20260505-0
file: data/en.wikipedia.org/wiki/Integrated_asset_modelling-0.md
category: reference
title: Integrated asset modelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Integrated_asset_modelling
date_saved: 2026-05-05T10:00:57.298855+00:00
instance: kb-cron
parent: integrated-asset-modelling-20260505-0
summary:
Integrated asset modelling (IAM) is the generic term used in the oil industry for computer modelling of both the subsurface and the surface elements of a field development. Historically the reservoir has always been modelled separately from the surface network and the facilities. In order to capture the interaction between those two or more standalone models, several time-consuming iterations were required. For example, a change in the water breakthrough leads to a change in the deliverability of the surface network which in turn leads to a production acceleration or deceleration in the reservoir. In order to go through this lengthy process more quickly, the industry has slowly been adopting a more integrated approach which captures the constraints imposed by the infrastructure on the network immediately. == Basis == As the aim of an IAM is to provide a production forecast which honours both the physical realities of the reservoir and the infrastructure it needs to contain the following elements; A pressure network A subsurface saturation model An availability model A constraint manager A production optimisation algorithm Some but not all models also contain an economics and risk model component so that the IAM can be used for economic evaluation. ==


id: knowledge-representation-and-reasoning-20260505-0
file: data/en.wikipedia.org/wiki/Knowledge_representation_and_reasoning-0.md
category: reference
title: Knowledge representation and reasoning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Knowledge_representation_and_reasoning
date_saved: 2026-05-05T10:00:58.436297+00:00
instance: kb-cron
parent: knowledge-representation-and-reasoning-20260505-0
summary:
Knowledge representation (KR) aims to model information in a structured manner to formally represent it as knowledge in knowledge-based systems whereas knowledge representation and reasoning (KRR, KR&R, or KR²) also aims to understand, reason, and interpret knowledge. KRR is widely used in the field of artificial intelligence (AI) with the goal of representing information about the world in a form that a computer system can use to solve complex tasks, such as diagnosing a medical condition or having a natural-language dialog. KR incorporates findings from psychology about how humans solve problems and represent knowledge, in order to design formalisms that make complex systems easier to design and build. KRR also incorporates findings from logic to automate various kinds of reasoning. Traditional KRR focuses more on the declarative representation of knowledge. Related knowledge representation formalisms mainly include vocabularies, thesaurus, semantic networks, axiom systems, frames, rules, logic programs, and ontologies. Examples of automated reasoning engines include inference engines, theorem provers, model generators, and classifiers. In a broader sense, parameterized models in machine learning — including neural network architectures such as convolutional neural networks and transformers — can also be regarded as a family of knowledge representation formalisms. The question of which formalism


id: knowledge-representation-and-reasoning-20260505-1
file: data/en.wikipedia.org/wiki/Knowledge_representation_and_reasoning-1.md
category: reference
title: Knowledge representation and reasoning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Knowledge_representation_and_reasoning
date_saved: 2026-05-05T10:00:58.436297+00:00
instance: kb-cron
parent: knowledge-representation-and-reasoning-20260505-0
summary:
The earliest work in computerized knowledge representation was focused on general problem-solvers such as the General Problem Solver (GPS) system developed by Allen Newell and Herbert A. Simon in 1959 and the Advice Taker proposed by John McCarthy also in 1959. GPS featured data structures for planning and decomposition. The system would begin with a goal. It would then decompose that goal into sub-goals and then set out to construct strategies that could accomplish each subgoal. The Advisor Taker, on the other hand, proposed the use of the predicate calculus to implement common sense reasoning. Many of the early approaches to knowledge representation in Artificial Intelligence (AI) used graph representations and semantic networks, similar to knowledge graphs today. In such approaches, problem solving was a form of graph traversal or path-finding, as in the A* search algorithm. Typical applications included robot plan-formation and game-playing. Other researchers focused on developing automated theorem-provers for first-order logic, motivated by the use of mathematical logic to formalise mathematics and to automate the proof of mathematical theorems. A major step in this direction was the development of the resolution method by John Alan Robinson. In the meanwhile, John McCarthy and Pat Hayes developed the situation


id: knowledge-representation-and-reasoning-20260505-2
file: data/en.wikipedia.org/wiki/Knowledge_representation_and_reasoning-2.md
category: reference
title: Knowledge representation and reasoning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Knowledge_representation_and_reasoning
date_saved: 2026-05-05T10:00:58.436297+00:00
instance: kb-cron
parent: knowledge-representation-and-reasoning-20260505-0
summary:
Any mechanically embodied intelligent process will be comprised of structural ingredients that a) we as external observers naturally take to represent a propositional account of the knowledge that the overall process exhibits, and b) independent of such external semantic attribution, play a formal but causal and essential role in engendering the behavior that manifests that knowledge. One of the most active areas of knowledge representation research is the Semantic Web. The Semantic Web seeks to add a layer of semantics (meaning) on top of the current Internet. Rather than indexing web sites and pages via keywords, the Semantic Web creates large ontologies of concepts. Searching for a concept will be more effective than traditional text only searches. Frame languages and automatic classification play a big part in the vision for the future Semantic Web. The automatic classification gives developers technology to provide order on a constantly evolving network of knowledge. Defining ontologies that are static and incapable of evolving on the fly would be very limiting for Internet-based systems. The classifier technology provides the ability to deal with the dynamic environment of the Internet. Recent projects funded primarily by the Defense Advanced Research Projects Agency (DARPA) have integrated frame languages


id: knowledge-representation-and-reasoning-20260505-3
file: data/en.wikipedia.org/wiki/Knowledge_representation_and_reasoning-3.md
category: reference
title: Knowledge representation and reasoning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Knowledge_representation_and_reasoning
date_saved: 2026-05-05T10:00:58.436297+00:00
instance: kb-cron
parent: knowledge-representation-and-reasoning-20260505-0
summary:
"A knowledge representation (KR) is most fundamentally a surrogate, a substitute for the thing itself, used to enable an entity to determine consequences by thinking rather than acting," i.e., "by reasoning about the world rather than taking action in it." "It is a set of ontological commitments", i.e., "an answer to the question: In what terms should I think about the world?" "It is a fragmentary theory of intelligent reasoning, expressed in terms of three components: (i) the representation's fundamental conception of intelligent reasoning; (ii) the set of inferences the representation sanctions; and (iii) the set of inferences it recommends." "It is a medium for pragmatically efficient computation", i.e., "the computational environment in which thinking is accomplished. One contribution to this pragmatic efficiency is supplied by the guidance a representation provides for organizing information" so as "to facilitate making the recommended inferences." "It is a medium of human expression", i.e., "a language in which we say things about the world." Knowledge representation and reasoning are a key enabling technology for the Semantic Web. Languages based on the Frame model with automatic classification provide a layer of semantics on top of the existing Internet. Rather than searching via text strings as


id: knowledge-representation-and-reasoning-20260505-4
file: data/en.wikipedia.org/wiki/Knowledge_representation_and_reasoning-4.md
category: reference
title: Knowledge representation and reasoning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Knowledge_representation_and_reasoning
date_saved: 2026-05-05T10:00:58.436297+00:00
instance: kb-cron
parent: knowledge-representation-and-reasoning-20260505-0
summary:
Primitives. What is the underlying framework used to represent knowledge? Semantic networks were one of the first knowledge representation primitives. Also, data structures and algorithms for general fast search. In this area, there is a strong overlap with research in data structures and algorithms in computer science. In early systems, the Lisp programming language, which was modeled after the lambda calculus, was often used as a form of functional knowledge representation. Frames and Rules were the next kind of primitive. Frame languages had various mechanisms for expressing and enforcing constraints on frame data. All data in frames are stored in slots. Slots are analogous to relations in entity-relation modeling and to object properties in object-oriented modeling. Another technique for primitives is to define languages that are modeled after First Order Logic (FOL). The most well known example is Prolog, but there are also many special-purpose theorem-proving environments. These environments can validate logical models and can deduce new theories from existing models. Essentially they automate the process a logician would go through in analyzing a model. Theorem-proving technology had some specific practical applications in the areas of software engineering. For example, it is possible to prove that a software program rigidly


id: knowledge-representation-and-reasoning-20260505-5
file: data/en.wikipedia.org/wiki/Knowledge_representation_and_reasoning-5.md
category: reference
title: Knowledge representation and reasoning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Knowledge_representation_and_reasoning
date_saved: 2026-05-05T10:00:58.436297+00:00
instance: kb-cron
parent: knowledge-representation-and-reasoning-20260505-0
summary:
In the early years of knowledge-based systems the knowledge-bases were fairly small. The knowledge-bases that were meant to actually solve real problems rather than do proof of concept demonstrations needed to focus on well defined problems. So for example, not just medical diagnosis as a whole topic, but medical diagnosis of certain kinds of diseases. As knowledge-based technology scaled up, the need for larger knowledge bases and for modular knowledge bases that could communicate and integrate with each other became apparent. This gave rise to the discipline of ontology engineering, designing and building large knowledge bases that could be used by multiple projects. One of the leading research projects in this area was the Cyc project. Cyc was an attempt to build a huge encyclopedic knowledge base that would contain not just expert knowledge but common-sense knowledge. In designing an artificial intelligence agent, it was soon realized that representing common-sense knowledge, knowledge that humans simply take for granted, was essential to make an AI that could interact with humans using natural language. Cyc was meant to address this problem. The language they defined was known as CycL. After CycL, a number of ontology languages have been developed. Most are declarative


id: metamodeling-20260505-0
file: data/en.wikipedia.org/wiki/Metamodeling-0.md
category: reference
title: Metamodeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Metamodeling
date_saved: 2026-05-05T10:00:59.634578+00:00
instance: kb-cron
parent: metamodeling-20260505-0
summary:
A metamodel is a model of a model, and metamodeling is the process of generating such metamodels. Thus metamodeling or meta-modeling is the analysis, construction, and development of the frames, rules, constraints, models, and theories applicable and useful for modeling a predefined class of problems. As its name implies, this concept applies the notions of meta- and modeling in software engineering and systems engineering. Metamodels are of many types and have diverse applications. == Overview == A metamodel/ surrogate model is a model of the model, i.e. a simplified model of an actual model of a circuit, system, or software-like entity. Metamodel can be a mathematical relation or algorithm representing input and output relations. A model is an abstraction of phenomena in the real world; a metamodel is yet another abstraction, highlighting the properties of the model itself. A model conforms to its metamodel in the way that a computer program conforms to the grammar of the programming language in which it is written. Various types of metamodels include polynomial equations, neural networks, Kriging, etc. "Metamodeling" is the construction of a collection of "concepts" (things, terms, etc.) within a certain domain. Metamodeling typically involves studying the output and input relationships


id: mixture-theory-20260505-0
file: data/en.wikipedia.org/wiki/Mixture_theory-0.md
category: reference
title: Mixture theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mixture_theory
date_saved: 2026-05-05T10:01:00.780760+00:00
instance: kb-cron
parent: mixture-theory-20260505-0
summary:
Mixture theory is used to model multiphase systems using the principles of continuum mechanics generalised to several interpenetrable continua. The basic assumption is that, at any instant of time, all phases are present at every material point, and momentum and mass balance equations are postulated. Like other models, mixture theory requires constitutive relations to close the system of equations. Krzysztof Wilmanski extended the model by introducing a balance equation of porosity. == References ==


id: model-dependent-realism-20260505-0
file: data/en.wikipedia.org/wiki/Model-dependent_realism-0.md
category: reference
title: Model-dependent realism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Model-dependent_realism
date_saved: 2026-05-05T10:01:01.927550+00:00
instance: kb-cron
parent: model-dependent-realism-20260505-0
summary:
Model-dependent realism is a view of scientific inquiry that focuses on the role of scientific models of phenomena. It claims reality should be interpreted based upon these models, and where several models overlap in describing a particular subject, multiple, equally valid, realities exist. It claims that it is meaningless to talk about the "true reality" of a model as we can never be absolutely certain of anything. The only meaningful thing is the usefulness of the model. The term "model-dependent realism" was coined by Stephen Hawking and Leonard Mlodinow in their 2010 book The Grand Design. == Overview == Model-dependent realism asserts that all we can know about "reality" consists of networks of world pictures that explain observations by connecting them by rules to concepts defined in models. Will an ultimate theory of everything be found? Hawking and Mlodinow suggest it is unclear: In the history of science we have discovered a sequence of better and better theories or models, from Plato to the classical theory of Newton to modern quantum theories. It is natural to ask: Will this sequence eventually reach an end point, an ultimate theory of the universe, that will include all forces and predict every observation


id: modeling-perspective-20260505-0
file: data/en.wikipedia.org/wiki/Modeling_perspective-0.md
category: reference
title: Modeling perspective
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Modeling_perspective
date_saved: 2026-05-05T10:01:03.065120+00:00
instance: kb-cron
parent: modeling-perspective-20260505-0
summary:
A modeling perspective in information systems is a particular way to represent pre-selected aspects of a system. Any perspective has a different focus, conceptualization, dedication and visualization of what the model is representing. The traditional way to distinguish between modeling perspectives is structural, functional and behavioral/processual perspectives. This together with rule, object, communication and actor and role perspectives is one way of classifying modeling approaches. == Types of perspectives == === Structural modeling perspective === This approach concentrates on describing the static structure. The main concept in this modeling perspective is the entity, this could be an object, phenomena, concept, thing etc. The data modeling languages have traditionally handled this perspective, examples of such being: The ER-language (Entity-Relationship) Generic Semantic Modeling language (GSM) Other approaches including: The NIAM language (Binary relationship language) Conceptual graphs (Sowa) Looking at the ER-language we have the basic components: Entities: Distinctively identifiable phenomenon. Relationships: An association among the entities. Attributes: Used to give value to a property of an entity/relationship. Looking at the generic semantic modeling language we have the basic components: Constructed types built by abstraction: Aggregation, generalization, and association. Attributes. Primitive types: Data types in GSM are classified into printable and abstract types.


id: nexus-tools-platform-20260505-0
file: data/en.wikipedia.org/wiki/Nexus_Tools_Platform-0.md
category: reference
title: Nexus Tools Platform
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nexus_Tools_Platform
date_saved: 2026-05-05T10:01:04.200363+00:00
instance: kb-cron
parent: nexus-tools-platform-20260505-0
summary:
The Nexus Tools Platform or NTP is a web-based inventory platform that allows an interactive comparison of environmental models in a statistical way. Developed by the UNU Institute for Integrated Management of Material Fluxes and of Resources (UNU-FLORES), the platform helps a user to analyze existing modelling tools related to environmental resource management and associated nexus perspectives, such as a Water-Energy-Food Nexus. As a result, the user can select the most appropriate tools to fit the research needs. == Integrated Resources Management (Nexus Approach) == Considering an increase in the global population, the demand for both food and water is expected to grow by more than 50% by 2050. At the same time, agricultural activity already puts significant stress on the quantity and quality of soils and freshwater resources worldwide. This leads to growing rates of land degradation and ecosystem deterioration. Long-term solutions to those challenges require integrated management of environmental resources which can be also referred to as a Nexus Approach. This approach focuses on the synergies between sectors in order to minimize trade-offs, increase resource use efficiency, and improve environmental policy & governance which is crucial for the achievement of the Sustainable Development Goals. For example, the sustainable


id: participatory-modeling-20260505-0
file: data/en.wikipedia.org/wiki/Participatory_modeling-0.md
category: reference
title: Participatory modeling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_modeling
date_saved: 2026-05-05T10:01:05.335906+00:00
instance: kb-cron
parent: participatory-modeling-20260505-0
summary:
Participatory modeling is a purposeful learning process for action that engages the implicit and explicit knowledge of stakeholders to create formalized and shared representation(s) of reality. In this process, the participants co-formulate the problem and use modeling practices to aid in the description, solution, and decision-making actions of the group. Participatory modeling is often used in environmental and resource management contexts. It can be described as engaging non-scientists in the scientific process. The participants structure the problem, describe the system, and create a shared understanding of how the system works. This can further lead to more quantitative analyses, and may sometimes result in a computer model of the system, which is then jointly used to test policy interventions, and propose one or more solutions. Participatory modeling is often used in natural resources management, such as forests or water. There are numerous benefits from this type of modeling, including a high degree of ownership and motivation towards change for the people involved in the modeling process. It also helps to develop more acceptable solutions and often creates more consensus among the stakeholders involved. == See also == Model-driven architecture Participatory design Participatory GIS Public participation GIS Problem structuring methods Shared vision


id: performance-and-modelling-of-ac-transmission-20260505-0
file: data/en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission-0.md
category: reference
title: Performance and modelling of AC transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission
date_saved: 2026-05-05T10:01:06.523639+00:00
instance: kb-cron
parent: performance-and-modelling-of-ac-transmission-20260505-0
summary:
Modelling of a transmission line is done to analyse its performance and characteristics. The gathered information vis simulating the model can be used to reduce losses or to compensate these losses. Moreover, it gives more insight into the working of transmission lines and helps to find a way to improve the overall transmission efficiency with minimum cost. == Performance modelling == Performance modelling is the abstraction of a real system into a simplified representation to enable the prediction of performance. The creation of a model can provide insight into how a proposed or actual system will or does work. This can, however, point towards different things to people belonging to different fields of work. Performance modelling has many benefits, which includes: Relatively inexpensive prediction of future performance. A clearer understanding of a system's performance characteristics. Additionally it may include, a mechanism for risk management and reduction with design support for future projects. A model will often be created specifically so that it can be interpreted by a software tool that simulates the system's behaviour, based on the information contained in the performance model. Such tools provide further insight into the system's behaviour and can be used to identify bottlenecks or


id: performance-and-modelling-of-ac-transmission-20260505-1
file: data/en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission-1.md
category: reference
title: Performance and modelling of AC transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission
date_saved: 2026-05-05T10:01:06.523639+00:00
instance: kb-cron
parent: performance-and-modelling-of-ac-transmission-20260505-0
summary:
In electrical engineering, the power factor of an AC electrical power system is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit, and is a dimensionless number in the closed interval of −1 to 1. A power factor of less than one indicates the voltage and current are not in phase, reducing the instantaneous product of the two. A negative power factor occurs when the device (which is normally the load) generates power, which then flows back towards the source. Real power is the instantaneous product of voltage and current and represents the capacity of the electricity for performing work. Apparent power is the average product of current and voltage. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power may be greater than the real power(pf ≤0.5). In an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase energy loss in


id: performance-and-modelling-of-ac-transmission-20260505-2
file: data/en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission-2.md
category: reference
title: Performance and modelling of AC transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission
date_saved: 2026-05-05T10:01:06.523639+00:00
instance: kb-cron
parent: performance-and-modelling-of-ac-transmission-20260505-0
summary:
==== Phase constant ==== The imaginary part of the propagation constant is the phase constant and is denoted by Greek lowercase letter β (beta). It causes the signal phase to shift along a transmission line. Generally denoted in radians per meter (rad/m). The propagation constant is denoted by Greek lowercase letter γ (gamma), and γ = α + jβ === Voltage Regulation === Voltage regulation is a measure of the change in the voltage magnitude between the sending and receiving end of a component, such as a transmission or distribution line. It is given in percentage for different lines. Mathematically, voltage regulation is given by, V . R = V n o − l o a d − V f u l l − l o a d V n o − l o a d {\displaystyle V.R={\frac {V_{no-load}-V_{full-load}}{V_{no-load}}}} == Line parameters of AC transmission == The AC transmission has four line parameters, these are the series resistance & inductance, and shunt capacitance and admittance. These parameters are responsible for distinct behavior of voltage and current waveforms along the transmission line. Line parameters are generally represented in their respective units per km of length in transmission lines. So these parameters


id: performance-and-modelling-of-ac-transmission-20260505-3
file: data/en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission-3.md
category: reference
title: Performance and modelling of AC transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission
date_saved: 2026-05-05T10:01:06.523639+00:00
instance: kb-cron
parent: performance-and-modelling-of-ac-transmission-20260505-0
summary:
L = μ 0 2 π l n D G M D r ′ H / m {\displaystyle L={\frac {\mu _{0}}{2\pi }}ln{\frac {D_{GMD}}{r\prime }}H/m} . Where, D G M D {\displaystyle D_{GMD}} is the geometric mean distance in between the conductors. If the lines are not properly transposed, the inductances become unequal and contain imaginary terms due to mutual inductances. In case of proper transposition, all the conductors occupy the available positions equal distance and thus the imaginary terms are cancelled out. And all the line inductances become equal. === Shunt capacitance === ==== Definition ==== Capacitance is the ratio of the change in an electric charge in a system to the corresponding change in its electric potential. The capacitance is a function only of the geometry of the design (e.g. area of the plates and the distance between them) and the permittivity of the dielectric material between the plates of the capacitor. For many dielectric materials, the permittivity and thus the capacitance is independent of the potential difference between the conductors and the total charge on them. The SI unit of capacitance is the farad (F). A 1 farad capacitor, when charged with 1 coulomb of electrical charge, has


id: performance-and-modelling-of-ac-transmission-20260505-4
file: data/en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission-4.md
category: reference
title: Performance and modelling of AC transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission
date_saved: 2026-05-05T10:01:06.523639+00:00
instance: kb-cron
parent: performance-and-modelling-of-ac-transmission-20260505-0
summary:
A two-port network (a kind of four-terminal network or quadripole) is an electrical network (circuit) or device with two pairs of terminals to connect to external circuits. Two terminals constitute a port if the currents applied to them satisfy the essential requirement known as the port condition: the electric current entering one terminal must equal the current emerging from the other terminal on the same port. The ports constitute interfaces where the network connects to other networks, the points where signals are applied or outputs are taken. In a two-port network, often port 1 is considered the input port and port 2 is considered the output port. The two-port network model is used in mathematical circuit analysis techniques to isolate portions of larger circuits. A two-port network is regarded as a "black box" with its properties specified by a matrix of numbers. This allows the response of the network to signals applied to the ports to be calculated easily, without solving for all the internal voltages and currents in the network. It also allows similar circuits or devices to be compared easily. For example, transistors are often regarded as two-ports, characterized by their h-parameters (see below) which are listed by


id: performance-and-modelling-of-ac-transmission-20260505-5
file: data/en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission-5.md
category: reference
title: Performance and modelling of AC transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission
date_saved: 2026-05-05T10:01:06.523639+00:00
instance: kb-cron
parent: performance-and-modelling-of-ac-transmission-20260505-0
summary:
=== Basis of classification === ==== Derivation of voltage\current wavelength ==== Current and voltage propagate in a transmission line with a speed equal to the speed of light (c) i.e. appx. 3 × 10 8 m / s e c = 3 × 10 5 k m / s e c {\displaystyle 3\times 10^{8}m/sec=3\times 10^{5}km/sec} and the frequency (f) of voltage or current is 50 Hz ( although in the America and parts of Asia it is typically 60 Hz) Therefore, wavelength (λ) can be calculated as below : f λ = c {\displaystyle f\lambda =c} or, λ = c f {\displaystyle \lambda ={\frac {c}{f}}} or, λ = 3 × 10 5 50 = 6000 K m {\displaystyle \lambda ={\frac {3\times 10^{5}}{50}}=6000Km} ==== Reason behind classification ==== A transmission line with 60 km of length is very very small( 1 100 {\displaystyle {\tfrac {1}{100}}} times) when compared with wavelength i.e. 6000 km. Up to 240 km ( 1 25 {\displaystyle {\tfrac {1}{25}}} times of wavelength) (250 km is taken for easy remembering) length of the line, current or voltage waveform is so small that it can be approximated to a straight line for all practical purposes. For line length of


id: performance-and-modelling-of-ac-transmission-20260505-6
file: data/en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission-6.md
category: reference
title: Performance and modelling of AC transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission
date_saved: 2026-05-05T10:01:06.523639+00:00
instance: kb-cron
parent: performance-and-modelling-of-ac-transmission-20260505-0
summary:
I 1 & I 3 {\displaystyle I_{1}\&I_{3}} are the currents through the shunt capacitances at the sending and receiving end respectively whereas I 2 {\displaystyle I_{2}} is the current through the series impedance. Again, V S = Z I 2 + V R = Z ( V R Y 2 + I R ) + V R {\displaystyle V_{S}=ZI_{2}+V_{R}=Z(V_{R}{\frac {Y}{2}}+I_{R})+V_{R}} or, So, by substituting we get : I S = Y 2 [ ( 1 + Y Z 2 ) V R + Z I R ] + Y 2 V R + I R {\displaystyle I_{S}={\frac {Y}{2}}[(1+{\frac {YZ}{2}})V_{R}+ZI_{R}]+{\frac {Y}{2}}V_{R}+I_{R}} or, The equation obtained thus, eq(4) & (5) can be written into matrix form as follows : so, the ABCD parameters are : A = D = ( 1 + Y Z 2 ) {\displaystyle (1+{\frac {YZ}{2}})} per unit B =Z Ω C = Y ( 1 + Y Z 4 ) ℧ {\displaystyle Y(1+{\frac {YZ}{4}})\mho } === Nominal T representation === In the nominal T model of a medium transmission line, the net series impedance is divided into two halves and placed on either side of the lumped shunt admittance i.e. placed in the middle. The circuit so formed


id: performance-and-modelling-of-ac-transmission-20260505-7
file: data/en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission-7.md
category: reference
title: Performance and modelling of AC transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Performance_and_modelling_of_AC_transmission
date_saved: 2026-05-05T10:01:06.523639+00:00
instance: kb-cron
parent: performance-and-modelling-of-ac-transmission-20260505-0
summary:
V r − Z c I r 2 e − γ l {\displaystyle {\frac {V_{r}-Z_{c}I_{r}}{2}}e^{-\gamma l}} is called reflected voltage wave We can rewrite the eq.(22) & eq.(23) as, So, by considering the corresponding analogy for long transmission line, the obtained equations i.e. eq.(24) eq.(25) can be written into matrix form as follows: The ABCD parameters are given by : A = D = cosh ⁡ γ l {\displaystyle \cosh \gamma l} B = Z c sinh ⁡ γ l {\displaystyle Z_{c}\sinh \gamma l} C = sinh ⁡ γ l Z c {\displaystyle {\frac {\sinh \gamma l}{Z_{c}}}} ==== Π Representation approach ==== Like the medium transmission line, the long line can also be approximated into an equivalent Π representation. In the Π-equivalent of a long transmission line, the series impedance is denoted by Z′ while the shunt admittance is denoted by Y′. So, the ABCD parameters of this long line can be defined like medium transmission line as : A = D = ( 1 + Y ′ Z ′ 2 ) {\displaystyle (1+{\frac {Y\prime Z\prime }{2}})} per unit B = Z′ Ω C = Y ( 1 + Y ′ Z ′ 4 ) ℧ {\displaystyle Y(1+{\frac {Y\prime Z\prime


id: process-map-20260505-0
file: data/en.wikipedia.org/wiki/Process_map-0.md
category: reference
title: Process map
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Process_map
date_saved: 2026-05-05T10:01:07.708970+00:00
instance: kb-cron
parent: process-map-20260505-0
summary:
Process map is a global-system process model that is used to outline the processes that make up the business system and how they interact with each other. Process map shows the processes as objects, which means it is a static and non-algorithmic view of the processes. It should be differentiated from a detailed process model, which shows a dynamic and algorithmic view of the processes, usually known as a process flow diagram. There are different notation standards that can be used for modelling process maps, but the most notable ones are TOGAF Event Diagram, Eriksson-Penker notation, and ARIS Value Added Chain. == Global process models == Global characteristics of the business system are captured by global or system models. Global process models are presented using different methodologies and sometimes under different names. Most notably, they are named process map in Visual Paradigm and MMABP, value-added chain in ARIS, and process diagram in Eriksson-Penker notation – which can easily lead to the confusion with process flow (detailed process model). Global models are mainly object-oriented and present a static view of the business system; they do not describe dynamic aspects of processes. A process map shows the presence of processes and their


id: process-map-20260505-1
file: data/en.wikipedia.org/wiki/Process_map-1.md
category: reference
title: Process map
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Process_map
date_saved: 2026-05-05T10:01:07.708970+00:00
instance: kb-cron
parent: process-map-20260505-0
summary:
=== Eriksson-Penker Diagram === Eriksson-Penker diagram is a tool used in business model analysis and design. It is named after Hans-Erik Eriksson and Magnus Penker, who developed the concept in their book "Business modelling with UML: Business Patterns at Work”. Eriksson-Penker diagrams are used to map out the key components of a business model and how they interact with one another. The diagrams typically consist of a series of boxes and lines that represent the different elements of the business model, such as the value proposition, customer segments, channels, revenue streams, and key resources. The lines between the boxes represent the relationships and dependencies between the different elements of the business model. These diagrams are useful for visualizing and understanding the various components of a business model, and can help organizations identify potential areas for improvement or areas of risk. They can also be used as a communication tool to help stakeholders understand the business model and its underlying assumptions. These diagrams are useful for visualizing and understanding the various components of a business model, and can help organizations identify potential areas for improvement or areas of risk. They can also be used as a communication tool to help stakeholders


id: quantitative-storytelling-20260505-0
file: data/en.wikipedia.org/wiki/Quantitative_storytelling-0.md
category: reference
title: Quantitative storytelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Quantitative_storytelling
date_saved: 2026-05-05T10:01:09.221216+00:00
instance: kb-cron
parent: quantitative-storytelling-20260505-0
summary:
Quantitative storytelling (QST) is a systematic approach to exploring the many frames potentially legitimate in a scientific study or controversy. QST assumes that, in an interconnected society, multiple frameworks and worldviews are legitimately upheld by different entities and social actors. QST looks critically at models used in evidence-based policy. Such models are often reductionist in that tractability (i.e. the possibility of proceeding towards a solution to a given problem) is achieved at the expense of suppressing available evidence. QST suggests corrective approaches to this practice. == Description == Quantitative storytelling (QST) addresses evidence-based policy and can be considered a reaction to methods of quantification with cost-benefit analysis or risk analysis. Jerome Ravetz and Steve Rayner discuss the concept that some of the evidence needed for policy is removed from view. They suggest that 'uncomfortable knowledge' is subtracted from the policy discourse with the objective of easing tractability or to advance a given agenda. The word 'hypo-cognition' has been used in the context of these instrumental uses of frames. According to Rayner, a phenomenon of "displacement" takes place when a model becomes the objective instead of the tool, for example, when an institution chooses to monitor and manage the outcome of


id: specification-language-20260505-0
file: data/en.wikipedia.org/wiki/Specification_language-0.md
category: reference
title: Specification language
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Specification_language
date_saved: 2026-05-05T10:01:10.410130+00:00
instance: kb-cron
parent: specification-language-20260505-0
summary:
A specification language is a formal language in computer science used during systems analysis, requirements analysis, and systems design to describe a system at a much higher level than a programming language, which is used to produce the executable code for a system. == Overview == Specification languages are generally not directly executed. They are meant to describe the what, not the how. It is considered an error if a requirement specification is cluttered with unnecessary implementation detail. A common fundamental assumption of many specification approaches is that programs are modelled as algebraic or model-theoretic structures that include a collection of sets of data values together with functions over those sets. This level of abstraction coincides with the view that the correctness of the input/output behaviour of a program takes precedence over all its other properties. In the property-oriented approach to specification (taken e.g. by CASL), specifications of programs consist mainly of logical axioms, usually in a logical system in which equality has a prominent role, describing the properties that the functions are required to satisfy—often just by their interrelationship. This is in contrast to so-called model-oriented specification in frameworks like VDM and Z, which consist of a simple realization


id: spherical-cow-20260505-0
file: data/en.wikipedia.org/wiki/Spherical_cow-0.md
category: reference
title: Spherical cow
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spherical_cow
date_saved: 2026-05-05T10:01:11.671992+00:00
instance: kb-cron
parent: spherical-cow-20260505-0
summary:
The spherical cow is a humorous metaphor for highly simplified scientific models of complex phenomena. Originating in theoretical physics, the metaphor refers to some scientific tendencies to develop toy models that reduce a problem to the simplest form imaginable, making calculations more feasible, even if the simplification hinders the model's application to reality. == History == The phrase comes from a joke that spoofs the simplifying assumptions sometimes used in theoretical physics. Milk production at a dairy farm was low, so the farmer wrote to the local university, asking for help from academia. A multidisciplinary team of professors was assembled, headed by a theoretical physicist, and two weeks of intensive on-site investigation took place. The scholars then returned to the university, notebooks crammed with data, where the task of writing the report was left to the team leader. Shortly thereafter the physicist returned to the farm, saying to the farmer, "I have the solution, but it works only in the case of spherical cows in a vacuum." John Harte, who received his Ph.D. from the University of Wisconsin in 1965, reported that he first heard the joke as a graduate student. One of the earliest published references is in a


id: astronomy-centre-20260505-0
file: data/en.wikipedia.org/wiki/Astronomy_Centre-0.md
category: reference
title: Astronomy Centre
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Astronomy_Centre
date_saved: 2026-05-05T10:01:13.184580+00:00
instance: kb-cron
parent: astronomy-centre-20260505-0
summary:
The Astronomy Centre, also known as the Amateur Astronomy Centre, is an astronomical observatory located in northern England which is run by experienced amateur astronomers and is open to the public at certain times. == History and purpose == Founded in November 1982 by Peter Drew, Linda Simonian and Rob Miller on the site of a disused factory, high in the Pennines, the Centre provides opportunities for its members, schools, local community groups and the general public to observe and photograph astronomical phenomena at a range of wavelengths during daylight and night hours. At the time the Centre was conceived, access to equipment and expertise was unavailable for many amateur astronomers in the UK and a national centre would have provided an invaluable focal point. Developments in optical fabrication, photography and communications now permit many visitors and members to complement their home astronomical facilities, skills and experience with those of the Astronomy Centre. In keeping with the Centres original ethos, besides welcoming visitors to the facility, current members engage off-site with schools, youth organisations and community groups and also provide contributions to national, regional, local print and broadcast media. == Structures == The first permanent housing on the site was


id: balance-of-angular-momentum-20260505-0
file: data/en.wikipedia.org/wiki/Balance_of_angular_momentum-0.md
category: reference
title: Balance of angular momentum
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Balance_of_angular_momentum
date_saved: 2026-05-05T10:01:14.393868+00:00
instance: kb-cron
parent: balance-of-angular-momentum-20260505-0
summary:
In classical mechanics, the balance of angular momentum, also known as Euler's second law, is a fundamental law of physics stating that a torque (a twisting force that causes rotation) must be applied to change the angular momentum (a measure of rotational motion) of a body. This principle, distinct from Newton's laws of motion, governs rotational dynamics. For example, to spin a playground merry-go-round, a push is needed to increase its angular momentum, while friction in the bearings and drag create opposing forces that slowly reduce it, eventually stopping the motion. First articulated by Swiss mathematician and physicist Leonhard Euler in 1775, the balance of angular momentum is a cornerstone of physics with broad applications. It implies the equality of corresponding shear stresses and the symmetry of the Cauchy stress tensor in continuum mechanics, a result also consistent with the Boltzmann Axiom, which posits that internal forces in a continuum are torque-free. These concepts—the balance of angular momentum, the symmetry of the Cauchy stress tensor, and the Boltzmann Axiom—are interconnected, as the former provides a physical basis for the latter two in continuum mechanics. It is also vital for analyzing systems like the spinning top, determining the skew-symmetric part of


id: balance-of-angular-momentum-20260505-1
file: data/en.wikipedia.org/wiki/Balance_of_angular_momentum-1.md
category: reference
title: Balance of angular momentum
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Balance_of_angular_momentum
date_saved: 2026-05-05T10:01:14.393868+00:00
instance: kb-cron
parent: balance-of-angular-momentum-20260505-0
summary:
must hold. This is actually the statement of the equality of corresponding shear stresses in the xy plane. == Cosserat Continuum == In addition to the torque-free classical continuum with a symmetric stress tensor, cosserat continua (polar continua) that are not torque-free have also been defined. One application of such a continuum is the theory of shells. Cosserat continua are not only capable to transport a momentum flux but also an angular momentum flux. Therefore, there also may be sources of momentum and angular momentum inside the body. Here the Boltzmann Axiom does not apply and the stress tensor may be skew-symmetric. If these fluxes are treated as usual in continuum mechanics, field equations arise in which the skew-symmetric part of the stress tensor has no energetic significance. The balance of angular momentum becomes independent of the balance of energy and is used to determine the skew-symmetric part of the stress tensor. American mathematician Clifford Truesdell saw in this the "true basic sense of Euler's second law". == Area rule == The area rule is a corollary of the angular momentum law in the form: The resulting moment is equal to the product of twice the mass and the time


id: euler-s-laws-of-motion-20260505-0
file: data/en.wikipedia.org/wiki/Euler's_laws_of_motion-0.md
category: reference
title: Euler's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Euler's_laws_of_motion
date_saved: 2026-05-05T10:01:15.563165+00:00
instance: kb-cron
parent: euler-s-laws-of-motion-20260505-0
summary:
In classical mechanics, Euler's laws of motion are equations of motion which extend Newton's laws of motion for point particle to rigid body motion. They were formulated by Leonhard Euler about 50 years after Isaac Newton formulated his laws. == Overview == === Euler's first law === Euler's first law states that the rate of change of linear momentum p of a rigid body is equal to the resultant of all the external forces Fext acting on the body: F ext = d p d t . {\displaystyle \mathbf {F} _{\text{ext}}={\frac {d\mathbf {p} }{dt}}.} Internal forces between the particles that make up a body do not contribute to changing the momentum of the body as there is an equal and opposite force resulting in no net effect. The linear momentum of a rigid body is the product of the mass of the body and the velocity of its center of mass vcm. === Euler's second law === Euler's second law states that the rate of change of angular momentum L about a point that is fixed in an inertial reference frame (often the center of mass of the body), is equal to the sum of the external moments of force


id: first-observation-of-gravitational-waves-20260505-0
file: data/en.wikipedia.org/wiki/First_observation_of_gravitational_waves-0.md
category: reference
title: First observation of gravitational waves
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves
date_saved: 2026-05-05T10:01:16.701964+00:00
instance: kb-cron
parent: first-observation-of-gravitational-waves-20260505-0
summary:
The first direct observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016. Previously, gravitational waves had been inferred only indirectly, via their effect on the timing of pulsars in binary star systems. The waveform, detected by both LIGO observatories, matched the predictions of general relativity for a gravitational wave emanating from the inward spiral and merger of two black holes (of 36 M☉ and 29 M☉) and the subsequent ringdown of a single, 62 M☉ black hole remnant. The signal was named GW150914 (from gravitational wave and the date of observation 2015-09-14). It was also the first observation of a binary black hole merger, demonstrating both the existence of binary stellar-mass black hole systems and the fact that such mergers could occur within the current age of the universe. This first direct observation was reported around the world as a remarkable accomplishment for many reasons. Efforts to directly prove the existence of such waves had been ongoing for over fifty years, and the waves are so minuscule that Albert Einstein himself doubted that they could ever be detected. The waves given off by the cataclysmic merger


id: first-observation-of-gravitational-waves-20260505-1
file: data/en.wikipedia.org/wiki/First_observation_of_gravitational_waves-1.md
category: reference
title: First observation of gravitational waves
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves
date_saved: 2026-05-05T10:01:16.701964+00:00
instance: kb-cron
parent: first-observation-of-gravitational-waves-20260505-0
summary:
Direct observation of gravitational waves was not possible for many decades following their prediction, due to the minuscule effect that would need to be detected and separated from the background of vibrations present everywhere on Earth. A technique called interferometry was suggested in the 1960s and eventually technology developed sufficiently for this technique to become feasible. In the present approach used by LIGO, a laser beam is split and the two halves are recombined after traveling different paths. Changes to the length of the paths or the time taken for the two split beams, caused by the effect of passing gravitational waves, to reach the point where they recombine are revealed as "beats". Such a technique is extremely sensitive to tiny changes in the distance or time taken to traverse the two paths. In theory, an interferometer with arms about 4 km long would be capable of revealing the change of space-time – a tiny fraction of the size of a single proton – as a gravitational wave of sufficient strength passed through Earth from elsewhere. This effect would be perceptible only to other interferometers of a similar size, such as the Virgo, GEO 600 and planned KAGRA and INDIGO


id: first-observation-of-gravitational-waves-20260505-2
file: data/en.wikipedia.org/wiki/First_observation_of_gravitational_waves-2.md
category: reference
title: First observation of gravitational waves
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves
date_saved: 2026-05-05T10:01:16.701964+00:00
instance: kb-cron
parent: first-observation-of-gravitational-waves-20260505-0
summary:
The event happened at a luminosity distance of 440+160−180 megaparsecs (determined by the amplitude of the signal), or 1.4±0.6 billion light years, corresponding to a cosmological redshift of 0.093+0.030−0.036 (90% credible intervals). Analysis of the signal along with the inferred redshift suggested that it was produced by the merger of two black holes with masses of 35+5−3 times and 30+3−4 times the mass of the Sun (in the source frame), resulting in a post-merger black hole of 62+4−3 M☉. The mass–energy of the missing 3.0±0.5 M☉ was radiated away in the form of gravitational waves. During the final 20 milliseconds of the merger, the power of the radiated gravitational waves peaked at about 3.6×1049 watts or 526 dBm – 50 times greater than the combined power of all light radiated by all the stars in the observable universe. The amount of this energy that was received by the entire planet Earth was about 36 billion joules, of which only a small amount was absorbed. Across the 0.2-second duration of the detectable signal, the relative tangential (orbiting) velocity of the black holes increased from 30% to 60% of the speed of light. The orbital frequency of 75 Hz (half the gravitational


id: first-observation-of-gravitational-waves-20260505-3
file: data/en.wikipedia.org/wiki/First_observation_of_gravitational_waves-3.md
category: reference
title: First observation of gravitational waves
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves
date_saved: 2026-05-05T10:01:16.701964+00:00
instance: kb-cron
parent: first-observation-of-gravitational-waves-20260505-0
summary:
=== Coincident gamma-ray observation === The Fermi Gamma-ray Space Telescope reported that its Gamma-Ray Burst Monitor (GBM) instrument detected a weak gamma-ray burst above 50 keV, starting 0.4 seconds after the LIGO event and with a positional uncertainty region overlapping that of the LIGO observation. The Fermi team calculated the odds of such an event being the result of a coincidence or noise at 0.22%. However a gamma ray burst would not have been expected, and observations from the INTEGRAL telescope's all-sky SPI-ACS instrument indicated that any energy emission in gamma-rays and hard X-rays from the event was less than one millionth of the energy emitted as gravitational waves, which "excludes the possibility that the event is associated with substantial gamma-ray radiation, directed towards the observer". If the signal observed by the Fermi GBM was genuinely astrophysical, INTEGRAL would have indicated a clear detection at a significance of 15 sigma above background radiation. The AGILE space telescope also did not detect a gamma-ray counterpart of the event. A follow-up analysis by an independent group, released in June 2016, developed a different statistical approach to estimate the spectrum of the gamma-ray transient. It concluded that Fermi GBM's data did not show


id: first-observation-of-gravitational-waves-20260505-4
file: data/en.wikipedia.org/wiki/First_observation_of_gravitational_waves-4.md
category: reference
title: First observation of gravitational waves
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves
date_saved: 2026-05-05T10:01:16.701964+00:00
instance: kb-cron
parent: first-observation-of-gravitational-waves-20260505-0
summary:
=== Expectations for detection of future binary merger events === On 15 June 2016, the LIGO group announced an observation of another gravitational wave signal, named GW151226. The Advanced LIGO was predicted to detect five more black hole mergers like GW150914 in its next observing campaign from November 2016 until August 2017 (it turned out to be seven), and then 40 binary star mergers each year, in addition to an unknown number of more exotic gravitational wave sources, some of which may not be anticipated by current theory. Planned upgrades are expected to double the signal-to-noise ratio, expanding the volume of space in which events like GW150914 can be detected by a factor of ten. Additionally, Advanced Virgo, KAGRA, and a possible third LIGO detector in India will extend the network and significantly improve the position reconstruction and parameter estimation of sources. Laser Interferometer Space Antenna (LISA) is a proposed space based observation mission to detect gravitational waves. With the proposed sensitivity range of LISA, merging binaries like GW150914 would be detectable about 1000 years before they merge, providing for a class of previously unknown sources for this observatory if they exist within about 10 megaparsecs. LISA Pathfinder, LISA's technology


id: first-observation-of-gravitational-waves-20260505-5
file: data/en.wikipedia.org/wiki/First_observation_of_gravitational_waves-5.md
category: reference
title: First observation of gravitational waves
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves
date_saved: 2026-05-05T10:01:16.701964+00:00
instance: kb-cron
parent: first-observation-of-gravitational-waves-20260505-0
summary:
=== Speed of gravitational waves and limit on possible mass of graviton === The speed of gravitational waves (vg) is predicted by general relativity to be the speed of light (c). The extent of any deviation from this relationship can be parameterized in terms of the mass of the hypothetical graviton. The graviton is the name given to an elementary particle that would act as the force carrier for gravity, in quantum theories about gravity. It is expected to be massless if, as it appears, gravitation has an infinite range. (This is because the more massive a gauge boson is, the shorter is the range of the associated force; as with the infinite range of electromagnetism, which is due to the massless photon, the infinite range of gravity implies that any associated force-carrying particle would also be massless.) If the graviton were not massless, gravitational waves would propagate below lightspeed, with lower frequencies (ƒ) being slower than higher frequencies, leading to dispersion of the waves from the merger event. No such dispersion was observed. The observations of the inspiral slightly improve (lower) the upper limit on the mass of the graviton from Solar System observations to 2.1×10−58 kg, corresponding to


id: global-horizontal-sounding-technique-20260505-0
file: data/en.wikipedia.org/wiki/Global_horizontal_sounding_technique-0.md
category: reference
title: Global horizontal sounding technique
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Global_horizontal_sounding_technique
date_saved: 2026-05-05T10:01:17.862849+00:00
instance: kb-cron
parent: global-horizontal-sounding-technique-20260505-0
summary:
The global horizontal sounding technique (GHOST) program was an atmospheric field research project in the late 1960s for investigating the technical ability to gather weather data using hundreds of simultaneous long-duration balloons for very long-range global scale numerical weather prediction in preparation for the Global Atmospheric Research Program (GARP). == Technology == The GHOST program was to demonstrate technology for a program that would, ultimately, gather data from thousands of balloons simultaneously. Unlike radiosonde balloons which collect vertical atmospheric sounding data over the release point during a relatively short ascent lasting a few hours, horizontal sounding balloons stay aloft for much longer periods lasting several weeks or months, floating at a constant-density altitude. The GHOST design explored the performance a superpressure balloon with a spherical two-layer PET film envelope holding the gas inside at a higher pressure than the surrounding atmosphere, allowing it to maintain a nearly constant altitude. These gas balloons float at a constant density altitude, where the balloon displaces a mass of air equal to its own mass. Expansion of the lifting gas due to solar heating is avoided in a superpressure balloon, since the inextensible PET film allows the pressure to rise as the gas is


id: hulunber-grassland-ecosystem-observation-and-research-station-20260505-0
file: data/en.wikipedia.org/wiki/Hulunber_Grassland_Ecosystem_Observation_and_Research_Station-0.md
category: reference
title: Hulunber Grassland Ecosystem Observation and Research Station
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hulunber_Grassland_Ecosystem_Observation_and_Research_Station
date_saved: 2026-05-05T10:01:19.075297+00:00
instance: kb-cron
parent: hulunber-grassland-ecosystem-observation-and-research-station-20260505-0
summary:
Hulunber Grassland Ecosystem Observation and Research Station in Inner Mongolia, China, is managed by the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS). It was established in 1997 and has an area of 400ha. This station is a multi-year fenced scientific observation site for a Stipa baicalensis-dominated temperate meadow steppe. The annual precipitation is 350mm-400mm, with an average of 380mm. The annual average temperature ranges from -3°C to 1°C. The soil structure is dominated by dark chestnut soil, the soil pH is 8.3 on average, and the soil density is 1.13g/cm~3. The main species in the observation site are Stipa Baicalensis, Leymus chinensis, Filifolium sibiricum, Artemisia dracunculus, and Pulsatilla chinensis. There are 25 families and 96 genera in total. The grass coverage of this site is more than 70%, with an average height of the canopy of 50 cm and an average depth of the root of 30 cm. == References ==


id: land-lab-20260505-0
file: data/en.wikipedia.org/wiki/Land_lab-0.md
category: reference
title: Land lab
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Land_lab
date_saved: 2026-05-05T10:01:20.219358+00:00
instance: kb-cron
parent: land-lab-20260505-0
summary:
A land lab is an area of land that has been set aside for use in biological studies. Thus, it is literally an outdoor laboratory based on an area of land. Studies may be elementary or advanced. For instance, students may simply be given the task of identifying all the tree species in a land lab, or an advanced student may be doing an intensive survey of the microbial life forms found in a soil sample. Hands on, tangible, project-base learning is a key aspect of land labs within an educational context. Land labs can exist anywhere with outdoor access: educational campuses, residential neighborhoods, peri-urban settings, urban settings, or even a small courtyard. The driving principle behind land lab education is getting outside and interacting with the world directly. Land labs are often marked out in plots or transects for studies. A plot may be any size, usually marked out in square meters. This allows for more intensive, delimited studies of changes and inventories of biota. Transects are straight lines at which, at intervals, measurements are taken for a profile of the ecological community. Land labs serve an important role in giving students access to a natural environment to observe


id: land-lab-20260505-1
file: data/en.wikipedia.org/wiki/Land_lab-1.md
category: reference
title: Land lab
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Land_lab
date_saved: 2026-05-05T10:01:20.219358+00:00
instance: kb-cron
parent: land-lab-20260505-0
summary:
== Footprints and Sizes of Land Labs == Land labs can be designed in all shapes and sizes. The key attributes of a land lab are typically the following: Building an outdoor learning area designated for cross-curricular studies in a STEM environment Establishing a focus on increasing biodiversity and restoring local environmental features Educating people about meeting humans needs sustainably through agriculture, energy production, shelter, and sanitation A small land lab could be as little as a courtyard, balcony garden, or a designated patch of land outside of a classroom window. Conversely, larger land lab could encompass hundreds of acres. The ideal size for a flexible land lab space allowing for many different ecological activities and circular systems is between 1/4 of an acre to 5 acres. == Sustainable societal solutions originating from land labs == Land labs are real-life environments by design. The project-based environment encourages students, teachers, and community members to experiment with ecological solutions that can be implemented on a small scale. Ideally, the solutions and systems implemented in a land lab are transferred beyond the land lab and into the surrounding community. Composting, rainwater catchment, food-waste upcycling with methane digesters and BSF, local food production, harnessing


id: list-of-environmental-sampling-techniques-20260505-0
file: data/en.wikipedia.org/wiki/List_of_environmental_sampling_techniques-0.md
category: reference
title: List of environmental sampling techniques
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_environmental_sampling_techniques
date_saved: 2026-05-05T10:01:21.407271+00:00
instance: kb-cron
parent: list-of-environmental-sampling-techniques-20260505-0
summary:
Environmental sampling techniques are used in biology, ecology and conservation as part of scientific studies to learn about the flora and fauna of a particular area and establish a habitat's biodiversity, the abundance of species and the conditions in which these species live amongst other information. Where species are caught, researchers often then take the trapped organisms for further study in a lab or are documented by a researcher in the field before the animal is released. This information can then be used to better understand the environment, its ecology, the behaviour of species and how organisms interact with one another and their environment. Here is a list of some sampling techniques and equipment used in environmental sampling: Quadrats - used for plants and slow moving animals == Techniques for birds and/or flying invertebrates and/or bats == Malaise Trap Flight Interception Trap Harp Trap Robinson Trap Butterfly Net Mist Net == Techniques for Terrestrial Animals == Transect Tullgren Funnel - used for soil-living arthropods Pitfall Trap - used for small terrestrial animals like insects and amphibians Netting techniques for terrestrial animals Beating Net - used for insects dwelling in trees and shrubs Sweep Netting - used for insects in grasses


id: megatransect-20260505-0
file: data/en.wikipedia.org/wiki/MegaTransect-0.md
category: reference
title: MegaTransect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/MegaTransect
date_saved: 2026-05-05T10:01:22.552842+00:00
instance: kb-cron
parent: megatransect-20260505-0
summary:
MegaTransect was the name for a project conducted in Africa in 1999 by J. Michael Fay to spend 465 days on the expedition hike of 2,000 miles (3,219 kilometers) across the Congo Basin of Africa to survey the ecological and environmental status of the region. A transect is a term in ecology that denotes a survey of the natural vegetation through a particular area. The concept of a megatransect was conceived as a vegetation transect on a large scale that could be used to take an ecological census of the natural vegetation and ecosystems. Shortly after the hike, Fay successfully lobbied alongside the President of Gabon to create 13 new national parks. In 2002, US Secretary of State Colin Powell and other Bush administration members gave 53 million dollars to help preserve the Congo Basin. Mike Fay later went on to carry out the MegaFlyover in 2004. == Madagascar megatransect == Also in 2004, an international team conducted a "Megatransect" of the island of Madagascar. Dubbed "Hike Madagascar", the journey covered the entire island. Members met with rural farmers to help them improve their agricultural techniques and discuss their impact on the environment. == History of US megatransects == One


id: newton-s-law-of-cooling-20260505-0
file: data/en.wikipedia.org/wiki/Newton's_law_of_cooling-0.md
category: reference
title: Newton's law of cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_law_of_cooling
date_saved: 2026-05-05T10:01:23.867206+00:00
instance: kb-cron
parent: newton-s-law-of-cooling-20260505-0
summary:
In the study of heat transfer, Newton's law of cooling is a physical law which states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its environment. The law is frequently qualified to include the condition that the temperature difference is small and the nature of heat transfer mechanism remains the same. As such, it is equivalent to a statement that the heat transfer coefficient, which mediates between heat losses and temperature differences, is a constant. In heat conduction, Newton's law is generally followed as a consequence of Fourier's law. The thermal conductivity of most materials is only weakly dependent on temperature, so the constant heat transfer coefficient condition is generally met. In convective heat transfer, Newton's Law is followed for forced air or pumped fluid cooling, where the properties of the fluid do not vary strongly with temperature, but it is only approximately true for buoyancy-driven convection, where the velocity of the flow increases with temperature difference. In the case of heat transfer by thermal radiation, Newton's law of cooling holds only for very small temperature differences. When stated in terms of temperature differences, Newton's law


id: newton-s-law-of-cooling-20260505-1
file: data/en.wikipedia.org/wiki/Newton's_law_of_cooling-1.md
category: reference
title: Newton's law of cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_law_of_cooling
date_saved: 2026-05-05T10:01:23.867206+00:00
instance: kb-cron
parent: newton-s-law-of-cooling-20260505-0
summary:
Δ T ( t ) = T ( t ) − T env {\displaystyle \Delta T(t)=T(t)-T_{\text{env}}} is the time-dependent temperature difference between environment and object (SI unit: K). If the heat transfer coefficient and the temperature difference are uniform along the heat transfer surface, the above formula simplifies to: Q ˙ = h A ( T ( t ) − T env ) = h A Δ T ( t ) {\displaystyle {\dot {Q}}=hA\left(T(t)-T_{\text{env}}\right)=hA\,\Delta T(t)} . The heat transfer coefficient h depends upon physical properties of the fluid and the physical situation in which convection occurs. Therefore, a single usable heat transfer coefficient (one that does not vary significantly across the temperature-difference ranges covered during cooling and heating) must be derived or found experimentally for every system that is to be analyzed. Formulas and correlations are available in many references to calculate heat transfer coefficients for typical configurations and fluids. For laminar flows, the heat transfer coefficient is usually smaller than in turbulent flows because turbulent flows have strong mixing within the boundary layer on the heat transfer surface. Note the heat transfer coefficient changes in a system when a transition from laminar to turbulent flow occurs. === Biot number


id: newton-s-law-of-cooling-20260505-2
file: data/en.wikipedia.org/wiki/Newton's_law_of_cooling-2.md
category: reference
title: Newton's law of cooling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_law_of_cooling
date_saved: 2026-05-05T10:01:23.867206+00:00
instance: kb-cron
parent: newton-s-law-of-cooling-20260505-0
summary:
=== First-order transient response of lumped-capacitance objects === A body treated as a lumped capacitance object, with a total internal energy of U {\displaystyle U} (in joules), is characterized by a single uniform internal temperature, T ( t ) {\displaystyle T(t)} . The heat capacitance, C {\displaystyle C} , of the body is C = d U / d T {\displaystyle C=dU/dT} (in J/K), for the case of an incompressible material. The internal energy may be written in terms of the temperature of the body, the heat capacitance (taken to be independent of temperature), and a reference temperature at which the internal energy is zero: U = C ( T − T ref ) {\displaystyle U=C(T-T_{\text{ref}})} . Differentiating U {\displaystyle U} with respect to time gives: d U d t = C d T d t . {\displaystyle {\frac {dU}{dt}}=C\,{\frac {dT}{dt}}.} Applying the first law of thermodynamics to the lumped object gives d U d t = − Q ˙ {\textstyle {\frac {dU}{dt}}=-{\dot {Q}}} , where the rate of heat transfer out of the body, Q ˙ {\displaystyle {\dot {Q}}} , may be expressed by Newton's law of cooling, and where no work transfer occurs for an incompressible material. Thus,


id: newton-s-laws-of-motion-20260505-0
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-0.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
Newton's laws of motion are three physical laws that describe the relationship between the motion of an object and the forces acting on it. These laws, which provide the basis for Newtonian mechanics, can be paraphrased as follows: A body remains at rest, or in motion at a constant speed in a straight line, unless it is acted upon by a force. At any instant of time, the net force on a body is equal to the body's acceleration multiplied by its mass or, equivalently, the rate at which the body's momentum is changing with time. If two bodies exert forces on each other, these forces have the same magnitude but opposite directions. The three laws of motion were first stated by Isaac Newton in his Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), originally published in 1687. Newton used them to investigate and explain the motion of many physical objects and systems. In the time since Newton, new insights, especially around the concept of energy, built the field of classical mechanics on his foundations. In modern times, limitations to Newton's laws have been discovered; new theories were consequently developed, such as quantum mechanics and relativity to address the


id: newton-s-laws-of-motion-20260505-1
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-1.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
== Prerequisites == Newton's laws are often stated in terms of point or particle masses, that is, bodies whose volume is negligible. This is a reasonable approximation for real bodies when the motion of internal parts can be neglected, and when the separation between bodies is much larger than the size of each. For instance, the Earth and the Sun can both be approximated as pointlike when considering the orbit of the former around the latter, but the Earth is not pointlike when considering activities on its surface. The mathematical description of motion, or kinematics, is based on the idea of specifying positions using numerical coordinates. Movement is represented by these numbers changing over time: a body's trajectory is represented by a function that assigns to each value of a time variable the values of all the position coordinates. The simplest case is one-dimensional, that is, when a body is constrained to move only along a straight line. Its position can then be given by a single number, indicating where it is relative to some chosen reference point. For example, a body might be free to slide along a track that runs left to right, and so its location can


id: newton-s-laws-of-motion-20260505-2
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-2.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
== Laws == === First law === Every body continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it. Newton's first law expresses the principle of inertia: the natural behavior of a body is to move in a straight line at constant speed. A body's motion preserves the status quo, but external forces can perturb this. The modern understanding of Newton's first law is that no inertial observer is privileged over any other. The concept of an inertial observer makes quantitative the everyday idea of feeling no effects of motion. For example, a person standing on the ground watching a train go past is an inertial observer. If the observer on the ground sees the train moving smoothly in a straight line at a constant speed, then a passenger sitting on the train will also be an inertial observer: the train passenger feels no motion. The principle expressed by Newton's first law is that there is no way to say which inertial observer is "really" moving and which is "really" standing still. One observer's state of rest is another observer's state of uniform


id: newton-s-laws-of-motion-20260505-3
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-3.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
In other words, if one body exerts a force on a second body, the second body is also exerting a force on the first body, of equal magnitude in the opposite direction. Overly brief paraphrases of the third law, like "action equals reaction" might have caused confusion among generations of students: the "action" and "reaction" apply to different bodies. For example, consider a book at rest on a table. The Earth's gravity pulls down upon the book. The "reaction" to that "action" is not the support force from the table holding up the book, but the gravitational pull of the book acting on the Earth. Newton's third law relates to a more fundamental principle, the conservation of momentum. The latter remains true even in cases where Newton's statement does not, for instance when force fields as well as material bodies carry momentum (e.g., in electromagnetism), and when momentum is defined properly, in quantum mechanics as well. In Newtonian mechanics, if two bodies have momenta p 1 {\displaystyle \mathbf {p} _{1}} and p 2 {\displaystyle \mathbf {p} _{2}} respectively, then the total momentum of the pair is p = p 1 + p 2 {\displaystyle \mathbf {p} =\mathbf {p} _{1}+\mathbf {p}


id: newton-s-laws-of-motion-20260505-4
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-4.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
When a body is in uniform circular motion, the force on it changes the direction of its motion but not its speed. For a body moving in a circle of radius r {\displaystyle r} at a constant speed v {\displaystyle v} , its acceleration has a magnitude a = v 2 r {\displaystyle a={\frac {v^{2}}{r}}} and is directed toward the center of the circle. The force required to sustain this acceleration, called the centripetal force, is therefore also directed toward the center of the circle and has magnitude m v 2 / r {\displaystyle mv^{2}/r} . Many orbits, such as that of the Moon around the Earth, can be approximated by uniform circular motion. In such cases, the centripetal force is gravity, and by Newton's law of universal gravitation has magnitude G M m / r 2 {\displaystyle GMm/r^{2}} , where M {\displaystyle M} is the mass of the larger body being orbited. Therefore, the mass of a body can be calculated from observations of another body orbiting around it. Newton's cannonball is a thought experiment that interpolates between projectile motion and uniform circular motion. A cannonball that is lobbed weakly off the edge of a tall cliff will hit


id: newton-s-laws-of-motion-20260505-5
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-5.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
The fan and sail example is a situation studied in discussions of Newton's third law. In the situation, a fan is attached to a cart or a sailboat and blows on its sail. From the third law, one would reason that the force of the air pushing in one direction would cancel out the force done by the fan on the sail, leaving the entire apparatus stationary. However, because the system is not entirely enclosed, there are conditions in which the vessel will move; for example, if the sail is built in a manner that redirects the majority of the airflow back towards the fan, the net force will result in the vessel moving forward. == Work and energy == The concept of energy was developed after Newton's time, but it has become an inseparable part of what is considered "Newtonian" physics. Energy can broadly be classified into kinetic, due to a body's motion, and potential, due to a body's position relative to others. Thermal energy, the energy carried by heat flow, is a type of kinetic energy not associated with the macroscopic motion of objects but instead with the movements of the atoms and molecules of which they are


id: newton-s-laws-of-motion-20260505-6
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-6.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
=== Rotational analogues of Newton's laws === When Newton's laws are applied to rotating extended bodies, they lead to new quantities that are analogous to those invoked in the original laws. The analogue of mass is the moment of inertia, the counterpart of momentum is angular momentum, and the counterpart of force is torque. Angular momentum is calculated with respect to a reference point. If the displacement vector from a reference point to a body is r {\displaystyle \mathbf {r} } and the body has momentum p {\displaystyle \mathbf {p} } , then the body's angular momentum with respect to that point is, using the vector cross product, L = r × p . {\displaystyle \mathbf {L} =\mathbf {r} \times \mathbf {p} .} Taking the time derivative of the angular momentum gives d L d t = ( d r d t ) × p + r × d p d t = v × m v + r × F . {\displaystyle {\frac {\mathrm {d} \mathbf {L} }{\mathrm {d} t}}=\left({\frac {\mathrm {d} \mathbf {r} }{\mathrm {d} t}}\right)\times \mathbf {p} +\mathbf {r} \times {\frac {\mathrm {d} \mathbf {p} }{\mathrm {d} t}}=\mathbf {v} \times m\mathbf {v} +\mathbf {r} \times \mathbf {F}


id: newton-s-laws-of-motion-20260505-7
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-7.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
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parent: newton-s-laws-of-motion-20260505-0
summary:
∂ v ∂ t + ( ∇ ⋅ v ) v = − 1 ρ ∇ P + f , {\displaystyle {\frac {\partial v}{\partial t}}+(\mathbf {\nabla } \cdot \mathbf {v} )\mathbf {v} =-{\frac {1}{\rho }}\mathbf {\nabla } P+\mathbf {f} ,} where ρ {\displaystyle \rho } is the density, P {\displaystyle P} is the pressure, and f {\displaystyle \mathbf {f} } stands for an external influence like a gravitational pull. Incorporating the effect of viscosity turns the Euler equation into a Navier–Stokes equation: ∂ v ∂ t + ( ∇ ⋅ v ) v = − 1 ρ ∇ P + ν ∇ 2 v + f , {\displaystyle {\frac {\partial v}{\partial t}}+(\mathbf {\nabla } \cdot \mathbf {v} )\mathbf {v} =-{\frac {1}{\rho }}\mathbf {\nabla } P+\nu \nabla ^{2}\mathbf {v} +\mathbf {f} ,} where ν {\displaystyle \nu } is the kinematic viscosity. === Singularities === It is mathematically possible for a collection of point masses, moving in accord with Newton's laws, to launch some of themselves away so forcefully that they fly off to infinity in a finite time. This unphysical behavior, known as a "noncollision singularity", depends upon the masses being pointlike and able to approach one another arbitrarily closely, as


id: newton-s-laws-of-motion-20260505-8
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-8.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
d q d t = p m , {\displaystyle {\frac {\mathrm {d} q}{\mathrm {d} t}}={\frac {p}{m}},} which reproduces the familiar statement that a body's momentum is the product of its mass and velocity. The time derivative of the momentum is d p d t = − d V d q , {\displaystyle {\frac {\mathrm {d} p}{\mathrm {d} t}}=-{\frac {\mathrm {d} V}{\mathrm {d} q}},} which, upon identifying the negative derivative of the potential with the force, is just Newton's second law once again. As in the Lagrangian formulation, in Hamiltonian mechanics the conservation of momentum can be derived using Noether's theorem, making Newton's third law an idea that is deduced rather than assumed. Among the proposals to reform the standard introductory-physics curriculum is one that teaches the concept of energy before that of force, essentially "introductory Hamiltonian mechanics". === Hamilton–Jacobi === The Hamilton–Jacobi equation provides yet another formulation of classical mechanics, one which makes it mathematically analogous to wave optics. This formulation also uses Hamiltonian functions, but in a different way than the formulation described above. The paths taken by bodies or collections of bodies are deduced from a function S ( q 1 , q 2 , … , t


id: newton-s-laws-of-motion-20260505-9
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-9.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
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parent: newton-s-laws-of-motion-20260505-0
summary:
=== Electromagnetism === Newton's three laws can be applied to phenomena involving electricity and magnetism, though subtleties and caveats exist. Coulomb's law for the electric force between two stationary, electrically charged bodies has much the same mathematical form as Newton's law of universal gravitation: the force is proportional to the product of the charges, inversely proportional to the square of the distance between them, and directed along the straight line between them. The Coulomb force that a charge q 1 {\displaystyle q_{1}} exerts upon a charge q 2 {\displaystyle q_{2}} is equal in magnitude to the force that q 2 {\displaystyle q_{2}} exerts upon q 1 {\displaystyle q_{1}} , and it points in the exact opposite direction. Coulomb's law is thus consistent with Newton's third law. Electromagnetism treats forces as produced by fields acting upon charges. The Lorentz force law provides an expression for the force upon a charged body that can be plugged into Newton's second law in order to calculate its acceleration. According to the Lorentz force law, a charged body in an electric field experiences a force in the direction of that field, a force proportional to its charge q {\displaystyle q} and to the strength of


id: newton-s-laws-of-motion-20260505-10
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-10.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
=== General relativity === General relativity is a theory of gravity that advances beyond that of Newton. In general relativity, the gravitational force of Newtonian mechanics is reimagined as curvature of spacetime. A curved path like an orbit, attributed to a gravitational force in Newtonian mechanics, is not the result of a force deflecting a body from an ideal straight-line path, but rather the body's attempt to fall freely through a background that is itself curved by the presence of other masses. A remark by John Archibald Wheeler that has become proverbial among physicists summarizes the theory: "Spacetime tells matter how to move; matter tells spacetime how to curve." Wheeler himself thought of this reciprocal relationship as a modern, generalized form of Newton's third law. The relation between matter distribution and spacetime curvature is given by the Einstein field equations, which require tensor calculus to express. The Newtonian theory of gravity is a good approximation to the predictions of general relativity when gravitational effects are weak and objects are moving slowly compared to the speed of light. === Quantum mechanics === Quantum mechanics is a theory of physics originally developed in order to understand microscopic phenomena: behavior at the scale


id: newton-s-laws-of-motion-20260505-11
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-11.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
Imagine any particle projected along a horizontal plane without friction; then we know, from what has been more fully explained in the preceding pages, that this particle will move along this same plane with a motion which is uniform and perpetual, provided the plane has no limits. Galileo recognized that in projectile motion, the Earth's gravity affects vertical but not horizontal motion. However, Galileo's idea of inertia was not exactly the one that would be codified into Newton's first law. Galileo thought that a body moving a long distance inertially would follow the curve of the Earth. This idea was corrected by Isaac Beeckman, Descartes, and Pierre Gassendi, who recognized that inertial motion should be motion in a straight line. Descartes published his laws of nature (laws of motion) with this correction in Principles of Philosophy (Principia Philosophiae) in 1644, with the heliocentric part toned down. First Law of Nature: Each thing when left to itself continues in the same state; so any moving body goes on moving until something stops it. Second Law of Nature: Each moving thing if left to itself moves in a straight line; so any body moving in a circle always tends to move away


id: newton-s-laws-of-motion-20260505-12
file: data/en.wikipedia.org/wiki/Newton's_laws_of_motion-12.md
category: reference
title: Newton's laws of motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Newton's_laws_of_motion
date_saved: 2026-05-05T10:01:25.048867+00:00
instance: kb-cron
parent: newton-s-laws-of-motion-20260505-0
summary:
Newton expressed his second law by saying that the force on a body is proportional to its change of motion, or momentum. By the time he wrote the Principia, he had already developed calculus (which he called "the science of fluxions"), but in the Principia he made no explicit use of it, perhaps because he believed geometrical arguments in the tradition of Euclid to be more rigorous. Consequently, the Principia does not express acceleration as the second derivative of position, and so it does not give the second law as F = m a {\displaystyle F=ma} . This form of the second law was written (for the special case of constant force) at least as early as 1716, by Jakob Hermann; Leonhard Euler would employ it as a basic premise in the 1740s. Euler pioneered the study of rigid bodies and established the basic theory of fluid dynamics. Pierre-Simon Laplace's five-volume Traité de mécanique céleste (1798–1825) forsook geometry and developed mechanics purely through algebraic expressions, while resolving questions that the Principia had left open, like a full theory of the tides. The concept of energy became a key part of Newtonian mechanics in the post-Newton period. Huygens' solution of the


id: observational-astronomy-20260505-0
file: data/en.wikipedia.org/wiki/Observational_astronomy-0.md
category: reference
title: Observational astronomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Observational_astronomy
date_saved: 2026-05-05T10:01:26.206992+00:00
instance: kb-cron
parent: observational-astronomy-20260505-0
summary:
Observational astronomy is a division of astronomy that is concerned with recording data about the observable universe, the practice and study of observing celestial objects with the use of telescopes and other astronomical instruments. As a science, the study of astronomy does not rely on direct experiments with the objects in a distant universe. Rather astronomers have a vast number of visible examples of stellar phenomena that can be examined. This allows for observational data to be plotted on graphs, and general trends recorded. Nearby examples of specific phenomena, such as variable stars, can then be used to infer the behavior of more distant representatives. Those distant yardsticks can then be employed to measure other phenomena in that neighborhood, including the distance to a galaxy. Galileo Galilei turned a telescope to the heavens and recorded what he saw. Since that time, observational astronomy has made steady advances with each improvement in telescope technology. == Subdivisions == A traditional division of observational astronomy is based on the region of the electromagnetic spectrum observed: Radio astronomy detects radiation of millimetre to decametre wavelength. The receivers are similar to those used in radio broadcast transmission but much more sensitive. See also Radio telescopes.


id: observational-astronomy-20260505-1
file: data/en.wikipedia.org/wiki/Observational_astronomy-1.md
category: reference
title: Observational astronomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Observational_astronomy
date_saved: 2026-05-05T10:01:26.206992+00:00
instance: kb-cron
parent: observational-astronomy-20260505-0
summary:
=== Measuring results === Astronomers have a number of observational tools that they can use to make measurements of the heavens. For objects that are relatively close to the Sun and Earth, direct and very precise position measurements can be made against a more distant (and thereby nearly stationary) background. Early observations of this nature were used to develop very precise orbital models of the various planets, and to determine their respective masses and gravitational perturbations. Such measurements led to the discovery of the planets Uranus, Neptune, and (indirectly) Pluto. They also resulted in an erroneous assumption of a fictional planet Vulcan within the orbit of Mercury (but the explanation of the precession of Mercury's orbit by Einstein is considered one of the triumphs of his general relativity theory). == Developments and diversity == In addition to examination of the universe in the optical spectrum, astronomers have increasingly been able to acquire information in other portions of the electromagnetic spectrum. The earliest such non-optical measurements were made of the thermal properties of the Sun. Instruments employed during a solar eclipse could be used to measure the radiation from the corona. === Radio astronomy === With the discovery of radio waves,


id: observational-astronomy-20260505-2
file: data/en.wikipedia.org/wiki/Observational_astronomy-2.md
category: reference
title: Observational astronomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Observational_astronomy
date_saved: 2026-05-05T10:01:26.206992+00:00
instance: kb-cron
parent: observational-astronomy-20260505-0
summary:
The key instrument of nearly all modern observational astronomy is the telescope. This serves the dual purposes of gathering more light so that very faint objects can be observed, and magnifying the image so that small and distant objects can be observed. Optical astronomy requires telescopes that use optical components of great precision. Typical requirements for grinding and polishing a curved mirror, for example, require the surface to be within a fraction of a wavelength of light of a particular conic shape. Many modern "telescopes" actually consist of arrays of telescopes working together to provide higher resolution through aperture synthesis. Large telescopes are housed in domes, both to protect them from the weather and to stabilize the environmental conditions. For example, if the temperature is different from one side of the telescope to the other, the shape of the structure changes, due to thermal expansion pushing optical elements out of position. This can affect the image. For this reason, the domes are usually bright white (titanium dioxide) or unpainted metal. Domes are often opened around sunset, long before observing can begin, so that air can circulate and bring the entire telescope to the same temperature as the surroundings. To prevent


id: observational-astronomy-20260505-3
file: data/en.wikipedia.org/wiki/Observational_astronomy-3.md
category: reference
title: Observational astronomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Observational_astronomy
date_saved: 2026-05-05T10:01:26.206992+00:00
instance: kb-cron
parent: observational-astronomy-20260505-0
summary:
=== Photoelectric photometry === Photoelectric photometry using the CCD is now frequently used to make observations through a telescope. These sensitive instruments can record the image nearly down to the level of individual photons, and can be designed to view in parts of the spectrum that are invisible to the eye. The ability to record the arrival of small numbers of photons over a period of time can allow a degree of computer correction for atmospheric effects, sharpening up the image. Multiple digital images can also be combined to further enhance the image, often known as "stacking". When combined with the adaptive optics technology, image quality can approach the theoretical resolution capability of the telescope. Filters are used to view an object at particular frequencies or frequency ranges. Multilayer film filters can provide very precise control of the frequencies transmitted and blocked, so that, for example, objects can be viewed at a particular frequency emitted only by excited hydrogen atoms. Filters can also be used to partially compensate for the effects of light pollution by blocking out unwanted light. Polarization filters can also be used to determine if a source is emitting polarized light, and the orientation of the polarization.


id: observatory-20260505-0
file: data/en.wikipedia.org/wiki/Observatory-0.md
category: reference
title: Observatory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Observatory
date_saved: 2026-05-05T10:01:27.492417+00:00
instance: kb-cron
parent: observatory-20260505-0
summary:
An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. The term observatoire has been used in French since at least 1976 to denote any institution that compiles and presents data on a particular subject (such as public health observatory) or for a particular geographic area (European Audiovisual Observatory). == Astronomical observatories == Astronomical observatories are mainly divided into four categories according to location: space-based, airborne, ground-based, and underground-based. Historically, ground-based observatories were as simple as containing a mural instrument (for measuring the angle between stars) or Stonehenge (which has some alignments on astronomical phenomena). Astronomical observatories may be private or they may be public. === Ground-based observatories === Ground-based observatories, located on the surface of Earth, are used to make observations in the radio and visible light portions of the electromagnetic spectrum. Most optical telescopes are housed within a dome or similar structure, to protect the delicate instruments from the elements. Telescope domes have a slit or other opening in the roof that can be opened during observing, and closed when the telescope is not in use. In most cases,


id: observatory-20260505-1
file: data/en.wikipedia.org/wiki/Observatory-1.md
category: reference
title: Observatory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Observatory
date_saved: 2026-05-05T10:01:27.492417+00:00
instance: kb-cron
parent: observatory-20260505-0
summary:
825: Al-Shammisiyyah Observatory, Baghdad, Iraq 869: Mahodayapuram Observatory, Kerala, India 1259: Maragheh Observatory, Azerbaijan, Iran 1276: Gaocheng Astronomical Observatory, China 1420: Ulugh Beg Observatory, Samarqand, Uzbekistan 1442: Beijing Ancient Observatory, China 1577: Constantinople Observatory of Taqi ad-Din, Turkey 1580: Uraniborg, Denmark (present-day Sweden) 1581: Stjärneborg, Denmark (present-day Sweden) 1633: Leiden Observatory, Netherlands 1642: Panzano Observatory, Italy 1642: Round Tower, Denmark 1667: Paris Observatory, France 1675: Royal Greenwich Observatory, England 1695: Sukharev Tower, Russia 1711: Berlin Observatory, Germany 1724: Jantar Mantar, India 1753: Stockholm Observatory, Sweden 1753: Vilnius University Observatory, Lithuania 1753: Real Instituto y Observatorio de la Armada, Spain 1759: Trieste Observatory, Italy. 1757: Macfarlane Observatory, Scotland. 1759: Turin Observatory, Italy. 1764: Brera Astronomical Observatory, Italy. 1765: Mohr Observatory, Indonesia. 1771: Lviv Observatory, Ukraine. 1774: Observatory of the Vatican, Italy. 1785: Dunsink Observatory, Ireland. 1786: Madras Observatory, India. 1789: Armagh Observatory, Northern Ireland. 1790: Royal Observatory of Madrid, Spain, 1803: National Astronomical Observatory, Bogotá, Colombia. 1811: Tartu Old Observatory, Estonia 1812: Astronomical Observatory of Capodimonte, Naples, Italy 1830/1842: Depot of Charts & Instruments/US Naval Observatory, US 1830: Yale University Observatory Atheneum, US 1834: Helsinki University Observatory, Finland 1838: Hopkins Observatory, Williams College, US 1838: Loomis Observatory, Western Reserve Academy, US


id: observatory-20260505-2
file: data/en.wikipedia.org/wiki/Observatory-2.md
category: reference
title: Observatory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Observatory
date_saved: 2026-05-05T10:01:27.492417+00:00
instance: kb-cron
parent: observatory-20260505-0
summary:
A volcano observatory is an institution that conducts the monitoring of a volcano as well as research in order to understand the potential impacts of active volcanism. Among the best known are the Hawaiian Volcano Observatory and the Vesuvius Observatory. Mobile volcano observatories exist with the USGS VDAP (Volcano Disaster Assistance Program), to be deployed on demand. Each volcano observatory has a geographic area of responsibility it is assigned to whereby the observatory is tasked with spreading activity forecasts, analyzing potential volcanic activity threats and cooperating with communities in preparation for volcanic eruption. == See also == == References == == Further reading == Aubin, David; Charlotte Bigg, and H. Otto Sibum, eds. The Heavens on Earth: Observatories and Astronomy in Nineteenth-Century Science and Culture (Duke University Press; 2010) 384 pages; Topics include astronomy as military science in Sweden, the Pulkovo Observatory in the Russia of Czar Nicholas I, and physics and the astronomical community in late 19th-century America. Brunier, Serge, et al. Great Observatories of the World (2005). Dick, Steven. Sky and Ocean Joined: The U.S. Naval Observatory 1830–2000 (2003). Gressot Julien and Jeanneret Romain, « Determining the right time, or the establishment of a culture of astronomical precision


id: operation-moonwatch-20260505-0
file: data/en.wikipedia.org/wiki/Operation_Moonwatch-0.md
category: reference
title: Operation Moonwatch
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Operation_Moonwatch
date_saved: 2026-05-05T10:01:28.689584+00:00
instance: kb-cron
parent: operation-moonwatch-20260505-0
summary:
Operation Moonwatch (also known as Project Moonwatch and, more simply, as Moonwatch) was an amateur science program formally initiated by the Smithsonian Astrophysical Observatory (SAO) in 1956. The SAO organized Moonwatch as part of the International Geophysical Year (IGY). Its initial goal was to enlist the aid of amateur astronomers and other citizens who would help professional scientists spot the first artificial satellites. Until professionally staffed optical tracking stations came on-line in 1958, this network of amateur scientists and other interested citizens played a critical role in providing crucial information regarding the world's first satellites. == Origins of Moonwatch == Moonwatch's origins can be traced to two sources. In the United States, there was a thriving culture of amateur scientists including thousands of citizens who did astronomy for an avocation. During the Cold War, the United States also encouraged thousands of citizens to take part in the Ground Observer Corps, a nationwide program to spot Soviet bombers. Moonwatch brought together these two activities and attitudes, melding curiosity and vigilance into a thriving activity for citizens. Moonwatch, in other words, was an expression of 1950s popular culture and fixed properly within the context of the Cold War. Moonwatch was the brainchild


id: operation-moonwatch-20260505-1
file: data/en.wikipedia.org/wiki/Operation_Moonwatch-1.md
category: reference
title: Operation Moonwatch
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Operation_Moonwatch
date_saved: 2026-05-05T10:01:28.689584+00:00
instance: kb-cron
parent: operation-moonwatch-20260505-0
summary:
Sputnik 1's sudden launch was followed less than a month later with the Soviets orbiting Sputnik 2 and the dog Laika. It was Moonwatch teams, networked around the world, who provided tracking information needed by scientists in Western nations. For the opening months of the Space Age, members of Moonwatch were the only organized worldwide network that was prepared to spot and help track satellites. The information they provided was complemented by the radio tracking program called Minitrack the United States Navy operated as well as some information from amateur radio buffs. In many cases, Moonwatch teams also had the responsibility of communicating news of Sputnik and the first American satellites to the public. The public responded, in turn, with infectious enthusiasm as local radio stations aired times to spot satellites and local and national newspapers ran hundreds of articles that described the nighttime activities of Moonwatchers. Moonwatch caught the attention of those citizens interested in science or the Space Race during the late 1950s and much of the general public as well. Newspapers and popular magazines featured stories about Moonwatch regularly; dozens of articles appeared in the Los Angeles Times, The New Yorker, and the New York Times alone.


id: streetlight-effect-20260505-0
file: data/en.wikipedia.org/wiki/Streetlight_effect-0.md
category: reference
title: Streetlight effect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Streetlight_effect
date_saved: 2026-05-05T10:01:29.854458+00:00
instance: kb-cron
parent: streetlight-effect-20260505-0
summary:
The streetlight effect, or the drunkard's search principle, is a type of observational bias that occurs when people only search for something where it is easiest to look. Both names refer to a well-known joke: A policeman sees a drunk man searching for something under a streetlight and asks what the drunk has lost. He says he lost his keys and they both look under the streetlight together. After a few minutes the policeman asks if he is sure he lost them here, and the drunk replies, no, and that he lost them in the park. The policeman asks why he is searching here, and the drunk replies, "this is where the light is". The anecdote appears in a story of the Islamic folklore character Nasreddin. In an undated Persian version of the story, Nasreddin loses a ring in a dark room of his house but instead looks for it in the yard because there is "much more light" out there. According to Idries Shah, this tale is used by many Sufis, commenting upon people who seek exotic sources for enlightenment. The version with a drunk under a streetlight goes back at least to the 1920s, and has been used


id: transect-20260505-0
file: data/en.wikipedia.org/wiki/Transect-0.md
category: reference
title: Transect
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Transect
date_saved: 2026-05-05T10:01:31.001886+00:00
instance: kb-cron
parent: transect-20260505-0
summary:
A transect is a path along which one counts and records occurrences of the objects of study (e.g. plants). It requires an observer to move along a fixed path and to count occurrences along the path and, at the same time (in some procedures), obtain the distance of the object from the path. This results in an estimate of the area covered and an estimate of the way in which detectability increases from probability 0 (far from the path) towards 1 (near the path). Using the raw count and this probability function, one can arrive at an estimate of the actual density of objects. The estimation of the abundance of populations (such as terrestrial mammal species) can be achieved using a number of different types of transect methods, such as strip transects, line transects, belt transects, point transects, gradsects and curved line transects. == See also == Census – Compilation of information about a given population Mark and recapture – Animal population estimation method – Method for estimating a species population size Distance sampling – Methods for estimating the density and/or abundance of populations MegaTransect – 1999 ecological survey of Africa == References == == External links == The dictionary


id: weather-balloon-20260505-0
file: data/en.wikipedia.org/wiki/Weather_balloon-0.md
category: reference
title: Weather balloon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weather_balloon
date_saved: 2026-05-05T10:01:32.254307+00:00
instance: kb-cron
parent: weather-balloon-20260505-0
summary:
A weather balloon, also known as a sounding balloon, is a high-altitude balloon (HAB) that carries instruments into the stratosphere for measuring atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde. First invented in the late 19th century, weather balloons have overgone several remodels and are still used by researchers across Europe, North America, and Asia to this day. The balloon itself is made of latex and filled with either helium or hydrogen to produce lift. Balloons can be tracked by radar, RDF, or GPS. Balloons meant to stay at a constant altitude for long periods are known as transosondes. Weather balloons that do not carry an instrument pack are used to determine upper-level winds and the height of cloud layers. For such balloons, a theodolite or total station is used to track the balloon's azimuth and elevation, which are then converted to estimated wind speed and direction and/or cloud height, as applicable. Weather balloons are launched around the world for observations used to diagnose current conditions as well as by human forecasters and computer models for weather forecasting. Between 900 and 1,300 locations around the globe do routine releases, typically


id: weather-balloon-20260505-1
file: data/en.wikipedia.org/wiki/Weather_balloon-1.md
category: reference
title: Weather balloon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Weather_balloon
date_saved: 2026-05-05T10:01:32.254307+00:00
instance: kb-cron
parent: weather-balloon-20260505-0
summary:
=== Aerospace and rocket launch support === Weather balloons are also used as atmospheric sounding systems to assist with rocket launches. In a test performed by the Lukasiewicz Research Network - Institute of Aviation a balloon sounding system was used to assist the ILR-33 Amber sub-orbital rocket. In a series of test launches in 2019, the system acquired atmospheric data such as information on vertical wind profile in real time that was used in pre-launch procedures for the rocket. === Special uses === Specialized uses also exist, such as for aviation interests, pollution monitoring, photography or videography, and research. Examples include pilot balloons (Pibal). Field research programs often use mobile launchers from land vehicles as well as ships and aircraft (usually dropsondes in this case). In recent years, weather balloons have also been used for scattering human ashes at high altitudes. The weather balloon was also used to create the fictional entity 'Rover' during the production of the 1960s TV series The Prisoner in Portmeirion, Gwynedd, North Wales, UK in September 1966. This was retained in further scenes shot at MGM Borehamwood UK during 1966–67. Weather balloons have also been adapted as drifting platforms in chemistry and air quality research.


id: analysis-20260505-0
file: data/en.wikipedia.org/wiki/Analysis-0.md
category: reference
title: Analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Analysis
date_saved: 2026-05-05T10:01:33.841259+00:00
instance: kb-cron
parent: analysis-20260505-0
summary:
Analysis (pl.: analyses) is the process of breaking a complex topic or substance into smaller parts in order to gain a better understanding of it. The technique has been applied in the study of mathematics and logic since before Aristotle, though analysis as a formal concept is a relatively recent development. The word comes from the Ancient Greek ἀνάλυσις (analysis, "a breaking-up" or "an untying" from ana- "up, throughout" and lysis "a loosening"). From it also comes the word's plural, analyses. As a formal concept, the method has variously been ascribed to René Descartes (Discourse on the Method), and Galileo Galilei. It has also been ascribed to Isaac Newton, in the form of a practical method of physical discovery (which he did not name). The converse of analysis is synthesis: putting the pieces back together again in a new or different whole. == Academic analysis == Academic analysis is a systematic, methodological approach to inquiry used across scholarly disciplines to deconstruct complex ideas, texts, data, or systems. Its primary aim is to foster a deeper, evidence-based understanding, challenge assumptions, and contribute to a body of knowledge through critical examination and rigorous argumentation. This form of analysis is foundational to higher


id: analysis-20260505-1
file: data/en.wikipedia.org/wiki/Analysis-1.md
category: reference
title: Analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Analysis
date_saved: 2026-05-05T10:01:33.841259+00:00
instance: kb-cron
parent: analysis-20260505-0
summary:
=== Music === Musical analysis – a process attempting to answer the question "How does this music work?" Musical Analysis is a study of how the composers use the notes together to compose music. Those studying music will find differences with each composer's musical analysis, which differs depending on the culture and history of music studied. An analysis of music is meant to simplify the music for you. Schenkerian analysis Schenkerian analysis is a collection of music analysis that focuses on the production of the graphic representation. This includes both analytical procedure as well as the notational style. Simply put, it analyzes tonal music which includes all chords and tones within a composition. === Philosophy === Philosophical analysis – a general term for the techniques used by philosophers Philosophical analysis refers to the clarification and composition of words put together and the entailed meaning behind them. Philosophical analysis dives deeper into the meaning of words and seeks to clarify that meaning by contrasting the various definitions. It is the study of reality, justification of claims, and the analysis of various concepts. Branches of philosophy include logic, justification, metaphysics, values and ethics. If questions can be answered empirically, meaning it can


id: analysis-20260505-2
file: data/en.wikipedia.org/wiki/Analysis-2.md
category: reference
title: Analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Analysis
date_saved: 2026-05-05T10:01:33.841259+00:00
instance: kb-cron
parent: analysis-20260505-0
summary:
The synthetic proof proceeds by shewing that the proposed new truth involves certain admitted truths. An analytic proof begins by an assumption, upon which a synthetic reasoning is founded. The Greeks distinguished theoretic from problematic analysis. A theoretic analysis is of the following kind. To prove that A is B, assume first that A is B. If so, then, since B is C and C is D and D is E, therefore A is E. If this be known a falsity, A is not B. But if this be a known truth and all the intermediate propositions be convertible, then the reverse process, A is E, E is D, D is C, C is B, therefore A is B, constitutes a synthetic proof of the original theorem. Problematic analysis is applied in all cases where it is proposed to construct a figure which is assumed to satisfy a given condition. The problem is then converted into some theorem which is involved in the condition and which is proved synthetically, and the steps of this synthetic proof taken backwards are a synthetic solution of the problem. === Psychotherapy === Psychoanalysis – seeks to elucidate connections among unconscious components of patients' mental


id: animal-testing-20260505-0
file: data/en.wikipedia.org/wiki/Animal_testing-0.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals, as model organisms, in experiments that seek answers to scientific and medical questions. This approach can be contrasted with field studies in which animals are observed in their natural environments or habitats. Experimental research with animals is usually conducted in universities, medical schools, pharmaceutical companies, defense establishments, and commercial facilities that provide animal-testing services to the industry. The focus of animal testing varies on a continuum from pure research, focusing on developing fundamental knowledge of an organism, to applied research, which may focus on answering some questions of great practical importance, such as finding a cure for a disease. Examples of applied research include testing disease treatments, breeding, defense research, and toxicology, including cosmetics testing. In education, animal testing is sometimes a component of biology or psychology courses. Research using animal models has been central to most of the achievements of modern medicine. It has contributed to most of the basic knowledge in fields such as human physiology and biochemistry, and has played significant roles in fields such as neuroscience and infectious disease. The results have included the near-eradication of polio


id: animal-testing-20260505-1
file: data/en.wikipedia.org/wiki/Animal_testing-1.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
The earliest references to animal testing are found in the writings of the Greeks in the 2nd and 4th centuries BCE. Aristotle and Erasistratus were among the first to perform experiments on living animals. Galen, a 2nd-century Roman physician, performed post-mortem dissections of pigs and goats. Avenzoar, a 12th-century Arabic physician in Moorish Spain introduced an experimental method of testing surgical procedures before applying them to human patients. Discoveries in the 18th and 19th centuries included Antoine Lavoisier's use of a guinea pig in a calorimeter to prove that respiration was a form of combustion, and Louis Pasteur's demonstration of the germ theory of disease in the 1880s using anthrax in sheep. Robert Koch used animal testing of mice and guinea pigs to discover the bacteria that cause anthrax and tuberculosis. In the 1890s, Ivan Pavlov famously used dogs to describe classical conditioning. Research using animal models has been central to most of the achievements of modern medicine. It has contributed most of the basic knowledge in fields such as human physiology and biochemistry, and has played significant roles in fields such as neuroscience and infectious disease. For example, the results have included the near-eradication of polio and the development


id: animal-testing-20260505-2
file: data/en.wikipedia.org/wiki/Animal_testing-2.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
== Model organisms == === Invertebrates === Although many more invertebrates than vertebrates are used in animal testing, these studies are largely unregulated by law. The most frequently used invertebrate species are Drosophila melanogaster, a fruit fly, and Caenorhabditis elegans, a nematode worm. In the case of C. elegans, the worm's body is completely transparent and the precise lineage of all the organism's cells is known, while studies in the fly D. melanogaster can use an amazing array of genetic tools. These invertebrates offer some advantages over vertebrates in animal testing, including their short life cycle and the ease with which large numbers may be housed and studied. However, the lack of an adaptive immune system and their simple organs prevent worms from being used in several aspects of medical research such as vaccine development. Similarly, the fruit fly immune system differs greatly from that of humans, and diseases in insects can be different from diseases in vertebrates; however, fruit flies and waxworms can be useful in studies to identify novel virulence factors or pharmacologically active compounds. Several invertebrate systems are considered acceptable alternatives to vertebrates in early-stage discovery screens. Because of similarities between the innate immune system of insects


id: animal-testing-20260505-3
file: data/en.wikipedia.org/wiki/Animal_testing-3.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
Non-human primates (NHPs) are used in toxicology tests, studies of AIDS and hepatitis, studies of neurology, behavior and cognition, reproduction, genetics, and xenotransplantation. They are caught in the wild or purpose-bred. In the United States and China, most primates are domestically purpose-bred, whereas in Europe the majority are imported purpose-bred. The European Commission reported that in 2011, 6,012 monkeys were experimented on in European laboratories. According to the U.S. Department of Agriculture, there were 71,188 monkeys in U.S. laboratories in 2016. 23,465 monkeys were imported into the U.S. in 2014 including 929 who were caught in the wild. Most of the NHPs used in experiments are macaques; but marmosets, spider monkeys, and squirrel monkeys are also used, and baboons and chimpanzees are used in the US. As of 2015, there are approximately 730 chimpanzees in U.S. laboratories. In a survey in 2003, it was found that 89% of singly-housed primates exhibited self-injurious or abnormal stereotypyical behaviors including pacing, rocking, hair pulling, and biting among others. The first transgenic primate was produced in 2001, with the development of a method that could introduce new genes into a rhesus macaque. This transgenic technology is now being applied in the search for a


id: animal-testing-20260505-4
file: data/en.wikipedia.org/wiki/Animal_testing-4.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
The regulations that apply to animals in laboratories vary across species. In the U.S., under the Animal Welfare Act and the Guide for the Care and Use of Laboratory Animals (the Guide), published by the National Academy of Sciences, any procedure can be performed on an animal if it can be successfully argued that it is scientifically justified. Researchers are required to consult with the institution's veterinarian and its Institutional Animal Care and Use Committee (IACUC), which every research facility is obliged to maintain. The IACUC must ensure that alternatives, including non-animal alternatives, have been considered, that the experiments are not unnecessarily duplicative, and that pain relief is given unless it would interfere with the study. The IACUCs regulate all vertebrates in testing at institutions receiving federal funds in the USA. Although the Animal Welfare Act does not include purpose-bred rodents and birds, these species are equally regulated under Public Health Service policies that govern the IACUCs. The Public Health Service policy oversees the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC). The CDC conducts infectious disease research on nonhuman primates (due to end, according to an announcement in November 2025), rabbits, mice, and


id: animal-testing-20260505-5
file: data/en.wikipedia.org/wiki/Animal_testing-5.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
=== Numbers === Accurate global figures for animal testing are difficult to obtain; it has been estimated that 100 million vertebrates are experimented on around the world every year, 10–11 million of them in the EU. The Nuffield Council on Bioethics reports that global annual estimates range from 50 to 100 million animals. None of the figures include invertebrates such as shrimp and fruit flies.The USDA/APHIS has published the 2016 animal research statistics. Overall, the number of animals (covered by the Animal Welfare Act) used in research in the US rose 6.9% from 767,622 (2015) to 820,812 (2016). This includes both public and private institutions. By comparing with EU data, where all vertebrate species are counted, Speaking of Research estimated that around 12 million vertebrates were used in research in the US in 2016. A 2015 article published in the Journal of Medical Ethics, argued that the use of animals in the US has dramatically increased in recent years. Researchers found this increase is largely the result of an increased reliance on genetically modified mice in animal studies. In 1995, researchers at Tufts University Center for Animals and Public Policy estimated that 14–21 million animals were used in American laboratories


id: animal-testing-20260505-6
file: data/en.wikipedia.org/wiki/Animal_testing-6.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
In the U.S., Class A breeders are licensed by the U.S. Department of Agriculture (USDA) to sell animals for research purposes, while Class B dealers are licensed to buy animals from "random sources" such as auctions, pound seizure, and newspaper ads. Some Class B dealers have been accused of kidnapping pets and illegally trapping strays, a practice known as bunching. It was in part out of public concern over the sale of pets to research facilities that the 1966 Laboratory Animal Welfare Act was ushered in—the Senate Committee on Commerce reported in 1966 that stolen pets had been retrieved from Veterans Administration facilities, the Mayo Institute, the University of Pennsylvania, Stanford University, and Harvard and Yale Medical Schools. The USDA recovered at least a dozen stolen pets during a raid on a Class B dealer in Arkansas in 2003. Four states in the U.S.—Minnesota, Utah, Oklahoma, and Iowa—require their shelters to provide animals to research facilities. Fourteen states explicitly prohibit the practice, while the remainder either allow it or have no relevant legislation. In the European Union, animal sources are governed by Council Directive 86/609/EEC, which requires lab animals to be specially bred, unless the animal has been lawfully imported


id: animal-testing-20260505-7
file: data/en.wikipedia.org/wiki/Animal_testing-7.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
Regulations require that scientists use as few animals as possible, especially for terminal experiments. However, while policy makers consider suffering to be the central issue and see animal euthanasia as a way to reduce suffering, others, such as the RSPCA, argue that the lives of laboratory animals have intrinsic value. Regulations focus on whether particular methods cause pain and suffering, not whether their death is undesirable in itself. The animals are euthanized at the end of studies for sample collection or post-mortem examination; during studies if their pain or suffering falls into certain categories regarded as unacceptable, such as depression, infection that is unresponsive to treatment, or the failure of large animals to eat for five days; or when they are unsuitable for breeding or unwanted for some other reason. Methods of euthanizing laboratory animals are chosen to induce rapid unconsciousness and death without pain or distress. The methods that are preferred are those published by councils of veterinarians. The animal can be made to inhale a gas, such as carbon monoxide and carbon dioxide, by being placed in a chamber, or by use of a face mask, with or without prior sedation or anesthesia. Sedatives or anesthetics such as


id: animal-testing-20260505-8
file: data/en.wikipedia.org/wiki/Animal_testing-8.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
Genetic modification of animals to study disease. Transgenic animals have specific genes inserted, modified or removed, to mimic specific conditions such as single gene disorders, such as Huntington's disease. Other models mimic complex, multifactorial diseases with genetic components, such as diabetes, or even transgenic mice that carry the same mutations that occur during the development of cancer. These models allow investigations on how and why the disease develops, as well as providing ways to develop and test new treatments. The vast majority of these transgenic models of human disease are lines of mice, the mammalian species in which genetic modification is most efficient. Smaller numbers of other animals are also used, including rats, pigs, sheep, fish, birds, and amphibians. Studies on models of naturally occurring disease and condition. Certain domestic and wild animals have a natural propensity or predisposition for certain conditions that are also found in humans. Cats are used as a model to develop immunodeficiency virus vaccines and to study leukemia because their natural predisposition to FIV and Feline leukemia virus. Certain breeds of dog experience narcolepsy making them the major model used to study the human condition. Armadillos and humans are among only a few animal species


id: animal-testing-20260505-9
file: data/en.wikipedia.org/wiki/Animal_testing-9.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
Toxicology testing, also known as safety testing, is conducted by pharmaceutical companies testing drugs, or by contract animal testing facilities, such as Huntingdon Life Sciences, on behalf of a wide variety of customers. According to 2005 EU figures, around one million animals are used every year in Europe in toxicology tests; which are about 10% of all procedures. According to Nature, 5,000 animals are used for each chemical being tested, with 12,000 needed to test pesticides. The tests are conducted without anesthesia, because interactions between drugs can affect how animals detoxify chemicals, and may interfere with the results. Toxicology tests are used to examine finished products such as pesticides, medications, food additives, packing materials, and air freshener, or their chemical ingredients. Most tests involve testing ingredients rather than finished products, but according to BUAV, manufacturers believe these tests overestimate the toxic effects of substances; they therefore repeat the tests using their finished products to obtain a less toxic label. The substances are applied to the skin or dripped into the eyes; injected intravenously, intramuscularly, or subcutaneously; inhaled either by placing a mask over the animals and restraining them, or by placing them in an inhalation chamber; or administered orally, through


id: animal-testing-20260505-10
file: data/en.wikipedia.org/wiki/Animal_testing-10.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
metabolic tests, investigating pharmacokinetics—how drugs are absorbed, metabolized and excreted by the body when introduced orally, intravenously, intraperitoneally, intramuscularly, or transdermally. toxicology tests, which gauge acute, sub-acute, and chronic toxicity. Acute toxicity is studied by using a rising dose until signs of toxicity become apparent. Current European legislation demands that "acute toxicity tests must be carried out in two or more mammalian species" covering "at least two different routes of administration". Sub-acute toxicity is where the drug is given to the animals for four to six weeks in doses below the level at which it causes rapid poisoning, in order to discover if any toxic drug metabolites build up over time. Testing for chronic toxicity can last up to two years and, in the European Union, is required to involve two species of mammals, one of which must be non-rodent. efficacy studies, which test whether experimental drugs work by inducing the appropriate illness in animals. The drug is then administered in a double-blind controlled trial, which allows researchers to determine the effect of the drug and the dose-response curve. Specific tests on reproductive function, embryonic toxicity, or carcinogenic potential can all be required by law, depending on the result of


id: animal-testing-20260505-11
file: data/en.wikipedia.org/wiki/Animal_testing-11.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
The moral and ethical questions raised by performing experiments on animals are subject to debate, and viewpoints have shifted significantly over the 20th century. There remain disagreements about which procedures are useful for which purposes, as well as disagreements over which ethical principles apply to which species. A 2015 Gallup poll found that 67% of Americans were "very concerned" or "somewhat concerned" about animals used in research. A Pew poll taken the same year found 50% of American adults opposed the use of animals in research. Still, a wide range of viewpoints exist. The view that animals have moral rights (animal rights) is a philosophical position proposed by Tom Regan, among others, who argues that animals are beings with beliefs and desires, and as such are the "subjects of a life" with moral value and therefore moral rights. Regan still sees ethical differences between killing human and non-human animals, and argues that to save the former it is permissible to kill the latter. Likewise, a "moral dilemma" view suggests that avoiding potential benefit to humans is unacceptable on similar grounds, and holds the issue to be a dilemma in balancing such harm to humans to the harm done to animals


id: animal-testing-20260505-12
file: data/en.wikipedia.org/wiki/Animal_testing-12.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
=== Threats to researchers === Threats of violence to animal researchers are not uncommon. In 2006, a primate researcher at the University of California, Los Angeles (UCLA) shut down the experiments in his lab after threats from animal rights activists. The researcher had received a grant to use 30 macaque monkeys for vision experiments; each monkey was anesthetized for a single physiological experiment lasting up to 120 hours, and then euthanized. The researcher's name, phone number, and address were posted on the website of the Primate Freedom Project. Demonstrations were held in front of his home. A Molotov cocktail was placed on the porch of what was believed to be the home of another UCLA primate researcher; instead, it was accidentally left on the porch of an elderly woman unrelated to the university. The Animal Liberation Front claimed responsibility for the attack. As a result of the campaign, the researcher sent an email to the Primate Freedom Project stating "you win", and "please don't bother my family anymore". In another incident at UCLA in June 2007, the Animal Liberation Brigade placed a bomb under the car of a UCLA children's ophthalmologist who experiments on cats and rhesus monkeys; the bomb


id: animal-testing-20260505-13
file: data/en.wikipedia.org/wiki/Animal_testing-13.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
As the experimentation on animals increased, especially the practice of vivisection, so did criticism and controversy. In 1655, the advocate of Galenic physiology Edmund O'Meara said that "the miserable torture of vivisection places the body in an unnatural state". O'Meara and others argued pain could affect animal physiology during vivisection, rendering results unreliable. There were also objections ethically, contending that the benefit to humans did not justify the harm to animals. Early objections to animal testing also came from another angle—many people believed animals were inferior to humans and so different that results from animals could not be applied to humans. On the other side of the debate, those in favor of animal testing held that experiments on animals were necessary to advance medical and biological knowledge. Claude Bernard—who is sometimes known as the "prince of vivisectors" and the father of physiology, and whose wife, Marie Françoise Martin, founded the first anti-vivisection society in France in 1883—famously wrote in 1865 that "the science of life is a superb and dazzlingly lighted hall which may be reached only by passing through a long and ghastly kitchen". Arguing that "experiments on animals [. . .] are entirely conclusive for the toxicology and


id: animal-testing-20260505-14
file: data/en.wikipedia.org/wiki/Animal_testing-14.md
category: reference
title: Animal testing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal_testing
date_saved: 2026-05-05T10:01:38.284993+00:00
instance: kb-cron
parent: animal-testing-20260505-0
summary:
Most scientists and governments state that animal testing should cause as little suffering to animals as possible, and that animal tests should only be performed when there is no alternative. The "Three Rs" are guiding principles for the use of animals in research in most countries. Whilst replacement of animals, i.e. alternatives to animal testing, is one of the principles, their scope is much broader. Although such principles have been welcomed as a step forwards by some animal welfare groups, they have also been criticized as both outdated by current research, and of little practical effect in improving animal welfare. The scientists and engineers at Harvard's Wyss Institute have created "organs-on-a-chip", including the "lung-on-a-chip" and "gut-on-a-chip". Researchers at cellasys in Germany developed a "skin-on-a-chip". These tiny devices contain human cells in a 3-dimensional system that mimics human organs. The chips can be used instead of animals in in vitro disease research, drug testing, and toxicity testing. Researchers have also begun using 3-D bioprinters to create human tissues for in vitro testing. Another non-animal research method is in silico or computer simulation and mathematical modeling which seeks to investigate and ultimately predict toxicity and drug effects on humans without using animals.


id: archival-research-20260505-0
file: data/en.wikipedia.org/wiki/Archival_research-0.md
category: reference
title: Archival research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archival_research
date_saved: 2026-05-05T10:01:39.554526+00:00
instance: kb-cron
parent: archival-research-20260505-0
summary:
Archival research is a type of research which involves seeking out and extracting evidence from archival records. These records may be held either in collecting institutions, such as libraries and museums, or in the custody of the organization (whether a government body, business, family, or other agency) that originally generated or accumulated them, or in that of a successor body (transferring, or in-house archives). Archival research can be contrasted with (1) secondary research (undertaken in a library or online), which involves identifying and consulting secondary sources relating to the topic of enquiry; and (2) with other types of primary research and empirical investigation such as fieldwork and experiment. == History of archives organizations == The oldest archives have been in existence for hundreds of years. For instance, in Europe, the General Archive of the Crown of Aragon was instituted in 1318, or the Vatican Secret Archives which were started in the 17th century and contain state papers, papal account books, and papal correspondence dating back to the 8th century. The Archives Nationales in France was founded in 1790 during the French Revolution and has holdings that date back to AD 625, and other European archives have a similar provenance. Archives


id: archival-research-20260505-1
file: data/en.wikipedia.org/wiki/Archival_research-1.md
category: reference
title: Archival research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archival_research
date_saved: 2026-05-05T10:01:39.554526+00:00
instance: kb-cron
parent: archival-research-20260505-0
summary:
=== Locating archival collections === Prior to online search, union catalogs were an important tool for finding materials in libraries and archives. In the United States, the National Union Catalog and the National Union Catalog of Manuscript Collections have been used by researchers to locate archives although much of its information has since been migrated to online systems. An increasing number of archival institutions can be found via an online search. In addition, portals such as Europeana, the Digital Public Library of America and the National Library of Australia's Trove provide links to member institutions. In the UK, JISC hosts the ArchivesHub, while the OCLC's ArchiveGrid provides an international portal for mostly library based institutions, which use MARC as a cataloguing tool for their holdings. The Association of Canadian Archivists (ACA) has partnered with the software company Artefactual to create ArchivesCanada, while the Australian Society of Archivists have used the same software for their Directory of Archives in Australia. Many other online search tools have been made available to facilitate search and discovery, including the Location Register of English Literary Manuscripts and Letters, the ArchiveSearch guide to archival materials in institutions in Cambridge, UK, and CARTOMAC: Archives littéraires d'Afrique. If


id: archival-research-20260505-2
file: data/en.wikipedia.org/wiki/Archival_research-2.md
category: reference
title: Archival research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archival_research
date_saved: 2026-05-05T10:01:39.554526+00:00
instance: kb-cron
parent: archival-research-20260505-0
summary:
A reading room is a space, usually within or near the archive, where users can consult archival materials under staff supervision. The unique, fragile, or sensitive nature of some materials sometimes requires the certain kinds of restrictions on their use, handling, and/or duplication. Many archives restrict what kinds of items can be brought into a reading room from outside, such as pencils, notepads, bags, and even clothing, to guard against theft or risk of damage to materials. Further restrictions may be placed on the number of materials that can be consulted at any given time, such as limiting a user to one box at a time and requiring all materials to be laid flat and visible at all times. Some archives provide basic supplies including scrap paper and pencils or foam wedges for supporting unusually large materials. Duplication services may be available at the archive although the policies, costs, and time required can vary. Increasingly, archives also allow users to use their own devices, such as handheld cameras, cell phones, and even scanners, to duplicate materials. The use of white or any other glove, while popular in television programs, is not necessarily required for handling archival documents, due to concerns


id: art-based-research-20260505-0
file: data/en.wikipedia.org/wiki/Art-based_research-0.md
category: reference
title: Art-based research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Art-based_research
date_saved: 2026-05-05T10:01:40.700649+00:00
instance: kb-cron
parent: art-based-research-20260505-0
summary:
Art-based research is a mode of formal qualitative inquiry that uses artistic processes in order to understand and articulate the subjectivity of human experience. == History == The term was first coined by Elliot Eisner, who was a professor of Art and Education at the Stanford Graduate School of Education and one of the United States' leading academic minds. Eisner used the term "art-based research" as the title of a conference presentation held at Stanford University in 1993. Subsequently, the concept of art-based research was defined by Shaun McNiff, professor of Creative Arts Therapies at Lesley College, as "the systematic use of the artistic process, the actual making of artistic expressions in all of the different forms of the arts, as a primary way of understanding and examining experience by both researchers and the people that they involve in their studies". It was later additionally defined as "research that uses the arts, in the broadest sense, to explore, understand, represent and even challenge human action and experience". Many practitioners of art-based research trace the origins of their approach to the work of German arts theorist and psychologist Rudolf Arnheim, and American philosopher Susanne Langer, both of whom elucidated the use


id: aaalac-international-20260505-0
file: data/en.wikipedia.org/wiki/AAALAC_International-0.md
category: reference
title: AAALAC International
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/AAALAC_International
date_saved: 2026-05-05T10:01:41.804867+00:00
instance: kb-cron
parent: aaalac-international-20260505-0
summary:
AAALAC International is a private, nonprofit organization headquartered in Frederick, Maryland, that promotes the humane treatment of animals in science through voluntary accreditation and assessment programs. The accreditation program started in 1965, when some veterinarians and researchers organized the American Association for Accreditation of Laboratory Animal Care, or AAALAC. In 1996, AAALAC changed its name to the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC International). The organization said the name change reflected the organization's growth in other countries and its commitment to enhancing life sciences and quality animal care around the world. Since 2016, the organization is officially known only by its acronym, AAALAC International. There are currently about 1,000 organizations worldwide accredited through its program. Along with meeting all applicable local and national regulations, AAALAC accredited institutions must also demonstrate that they are achieving the standards outlined in the Guide for the Care and Use of Laboratory Animals, a document published since 1996 by the National Research Council of the U.S. National Academy of Sciences. The Guide includes standards go beyond what is required by law. == See also == Animal welfare Animal testing American Association for Laboratory Animal Science, a U.S. nonprofit organization Animal


