# kb

id: audit-study-20260505-0
file: data/en.wikipedia.org/wiki/Audit_study-0.md
category: reference
title: Audit study
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Audit_study
date_saved: 2026-05-05T10:01:58.929950+00:00
instance: kb-cron
parent: audit-study-20260505-0
summary:
A type of study used in economics, sociology, political science, and psychology, an audit study is one in which trained employees of the researcher ("auditors") are matched on all characteristics except the one being tested for discrimination. These auditors then apply for a service, be it a job, financial advice regarding their stock portfolio, housing, or a credit card, to test for discrimination. == Applications == Audit studies have been conducted to test the existence of discrimination in numerous occupations and services and in regards to multiple characteristics. For example, studies have been conducted to measure discrimination against racial minorities by real estate agents, racial discrimination in professional networking on LinkedIn and Twitter, requests on Airbnb, prices in online markets, emails to early childcare facilities as well as gender discrimination against women applying for restaurant jobs. Most employment-related audit studies have focused on overqualified college students applying for low-paying jobs during the summer. They have also been used to measure racial and gender discrimination in academia, racial discrimination in the low and high ends of the labor market, discrimination in social integration, and racial/ethnic discrimination in roommate selection. == Criticism == Audit studies have been criticized because the auditors may


id: autodidacticism-20260505-0
file: data/en.wikipedia.org/wiki/Autodidacticism-0.md
category: reference
title: Autodidacticism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Autodidacticism
date_saved: 2026-05-05T10:02:00.088315+00:00
instance: kb-cron
parent: autodidacticism-20260505-0
summary:
Autodidacticism (also autodidactism) or self-education (also self-learning, self-study, and self-teaching) is the practice of education without the guidance of teachers. Autodidacts are self-taught people who learn a subject through self-study. Autodidacticism may involve, complement, or be an alternative to formal education. Formal education itself may have a hidden curriculum that requires self-study for the uninitiated. Generally, autodidacts choose the subject they will study, their studying material, and the studying rhythm and time. Autodidacts may or may not have formal education, and their study may be either a complement or an alternative to formal education. Many notable contributions have been made by autodidacts. The self-learning curriculum is infinite. One may seek out alternative pathways in education and use these to gain competency; self-study may meet some prerequisite-curricula criteria for experiential education or apprenticeship. Self-education techniques can include reading educational books or websites, watching educational videos and listening to educational audio recordings, or by visiting infoshops. One uses some space as a learning space, where one uses critical thinking to develop study skills within the broader learning environment until they've reached an academic comfort zone. == Terminology == The term autodidact has its roots in the Ancient Greek words αὐτός (autós, lit.


id: autodidacticism-20260505-1
file: data/en.wikipedia.org/wiki/Autodidacticism-1.md
category: reference
title: Autodidacticism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Autodidacticism
date_saved: 2026-05-05T10:02:00.088315+00:00
instance: kb-cron
parent: autodidacticism-20260505-0
summary:
Autodidacticism is sometimes a complement of modern formal education. As a complement to formal education, students would be encouraged to do more independent work. Before the twentieth century, only a small minority of people received an advanced academic education. As stated by Joseph Whitworth in his influential report on industry and innovators dated from 1853, literacy rates were higher in the United States than in England. However, even in the U.S., most children were not completing high school. High school education was necessary to become a teacher. In modern times, a larger percentage of those completing high school also attended college, usually to pursue a professional degree, such as law or medicine, or a divinity degree. Collegiate teaching was based on the classics (Latin, philosophy, ancient history, theology) until the early nineteenth century. There were few if any institutions of higher learning offering studies in engineering or science before 1800. Institutions such as the Royal Society did much to promote scientific learning, including public lectures. In England, there were also itinerant lecturers offering their service, typically for a fee. Prior to the nineteenth century, there were many important inventors working as millwrights or mechanics who, typically, had received an elementary


id: autodidacticism-20260505-2
file: data/en.wikipedia.org/wiki/Autodidacticism-2.md
category: reference
title: Autodidacticism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Autodidacticism
date_saved: 2026-05-05T10:02:00.088315+00:00
instance: kb-cron
parent: autodidacticism-20260505-0
summary:
The first philosophical claim supporting an autodidactic program to the study of nature and God was in the philosophical novel Hayy ibn Yaqdhan (Alive son of the Vigilant), whose titular hero is considered the archetypal autodidact. The story is a medieval autodidactic utopia, a philosophical treatise in a literary form, which was written by the Andalusian philosopher Ibn Tufail in the 1160s in Marrakesh. It is a story about a feral boy, an autodidact prodigy who masters nature through instruments and reason, discovers laws of nature by practical exploration and experiments, and gains summum bonum through a mystical mediation and communion with God. The hero rises from his initial state of tabula rasa to a mystical or direct experience of God after passing through the necessary natural experiences. The focal point of the story is that human reason, unaided by society and its conventions or by religion, can achieve scientific knowledge, preparing the way to the mystical or highest form of human knowledge. Commonly translated as "The Self-Taught Philosopher" or "The Improvement of Human Reason", Ibn-Tufayl's story Hayy Ibn-Yaqzan inspired debates about autodidacticism in a range of historical fields from classical Islamic philosophy through Renaissance humanism and the European Enlightenment.


id: avian-ecology-field-methods-20260505-0
file: data/en.wikipedia.org/wiki/Avian_ecology_field_methods-0.md
category: reference
title: Avian ecology field methods
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Avian_ecology_field_methods
date_saved: 2026-05-05T10:02:01.276869+00:00
instance: kb-cron
parent: avian-ecology-field-methods-20260505-0
summary:
There are many field methods available for conducting avian ecological research. They can be divided into three types: counts, nest monitoring, and capturing and marking. == Basic counts == Basic bird counts are a good way to estimate population size, detect changes in population size or species diversity, and determine the cause of the changes if environmental or habitat data is collected as well. Basic bird counts can be completed fairly easily and inexpensively, and they provide general information about the status of a bird population. Birds can be directly counted on breeding colonies, and at roosts, flocks, or Leks. Large diurnal migrants, like many raptors, can be counted as they pass through migration bottlenecks. Small nocturnal migrants are harder to count, but many advances have been made in the use of radar and microphone arrays to identify and count them. === Point counts and area searches === Perhaps the simplest method of counting birds is called a "point count", in which a trained observer records all the birds seen and heard from a point count station for a set period of time. A series of point counts completed over a fixed route can then be compared to the results


id: braiding-knowledge-20260505-0
file: data/en.wikipedia.org/wiki/Braiding_knowledge-0.md
category: reference
title: Braiding knowledge
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Braiding_knowledge
date_saved: 2026-05-05T10:02:02.437237+00:00
instance: kb-cron
parent: braiding-knowledge-20260505-0
summary:
Braiding knowledge is a research framework that combines traditional knowledge with "Western" science to address contemporary issues. == Organizations == The following organizations center the use of braiding knowledge in their mission statements. === Center for Braiding Indigenous Knowledges and Science === The Center for Braiding Indigenous Knowledges and Science (CBIKS) was founded in 2023 with funding by the National Science Foundation’s Science and Technology Centers: Integrative Partnerships program by co-principal investigators: Sonya Atalay, Ora Marek-Martinez, Bonnie Newsom, and Jon Woodruff. The Center is located on the MIT campus with eight regional hubs across the U.S. and in Canada, Aotearoa New Zealand, and Australia. Research is fully community-driven and in full collaboration with community partners at all education levels. CBIKS is currently directed by Sonya Atalay. === Braiding Knowledge Project === The Braiding Knowledge Project, founded in 2021, is led by Melissa Tehee, Breanne Litts, and Rogelio Cardona-Rivera between Utah State University and the University of Utah with funding from the Spencer Foundation and the National Science Foundation. === Braiding Knowledges Canada (BKC) === BKC is a Canadian not-for-profit corporation established in 2019 that promotes decolonizing practices through place-based, community-driven environmental research. The corporation is supported by a five-year grant


id: nicole-brown-social-scientist-20260505-0
file: data/en.wikipedia.org/wiki/Nicole_Brown_(social_scientist)-0.md
category: reference
title: Nicole Brown (social scientist)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nicole_Brown_(social_scientist)
date_saved: 2026-05-05T10:02:03.633185+00:00
instance: kb-cron
parent: nicole-brown-social-scientist-20260505-0
summary:
Nicole Brown (born 1976) is an Austrian and British writer and academic whose expertise lies with social research practice. She focuses on the development and pragmatics of research methods and approaches for data analysis as well as dissemination. == Education == Brown has a teaching qualification (2001), a Magister degree from the University of Vienna (2001), a master's degree in teaching from the UCL Institute of Education (2006), a diploma in translation from the University of London (2008). She has a 2018 postgraduate certificate in higher education, a 2020 masters degree in higher education, and a PhD in sociology, all from the University of Kent. == Career == Associate Professor and IOE Head of Research Ethics and Integrity at University College London, and Director of Social Research & Practice and Education Ltd. Brown researches physical and material representations of experiences, the generation of knowledge and use of metaphors to express what is difficult to express, and more generally, research methods and approaches to explore identity and body work. Brown is an editor for the Journal of Participatory Research Methods, Disability and Society, and The Qualitative Report. She is a long-standing member of methodologically-orientated organisations, such as the Pedagogy Network of


id: chronosequence-20260505-0
file: data/en.wikipedia.org/wiki/Chronosequence-0.md
category: reference
title: Chronosequence
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chronosequence
date_saved: 2026-05-05T10:02:04.866584+00:00
instance: kb-cron
parent: chronosequence-20260505-0
summary:
A chronosequence describes a set of ecological sites that share similar attributes but represent different ages. A common assumption in establishing chronosequences is that no other variable besides age (such as various abiotic components and biotic components) has changed between sites of interest. Because this assumption cannot always be tested for environmental study sites, the use of chronosequences in field successional studies has recently been debated. == Applications == === Forest sciences === Since many processes in forest ecology take a long time (decades or centuries) to develop, chronosequence methods are used to represent and study the time-dependent development of a forest. Field data from a forest chronosequence can be collected in a short period of several months. === Soil science === Chronosequences used in soil studies consist of sites that have developed over different periods of time with relatively small differences in other soil-forming factors. Such groups of sites are used to assess the influence of time as a factor in pedogenesis. === Ecology === Chronosequences are often used to study the changes in plant communities during succession. A classic example of using chronosequences to study ecological succession is in the study of plant and microbial succession in recently


id: co-production-approach-20260505-0
file: data/en.wikipedia.org/wiki/Co-production_(approach)-0.md
category: reference
title: Co-production (approach)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Co-production_(approach)
date_saved: 2026-05-05T10:02:06.033625+00:00
instance: kb-cron
parent: co-production-approach-20260505-0
summary:
Co-production (or coproduction) is an approach in the development and delivery of public services and technology in which citizens and other key stakeholders and concepts in human society are implicitly involved in the process. In many countries, co-production is increasingly perceived as a new public administration paradigm as it involves a whole new thinking about public service delivery and policy development. In co-productive approaches, citizens are not only consulted, but are part of the conception, design, steering, and ongoing management of services. The concept has a long history, arising out of radical theories of knowledge in the 1970s, and can be applied in a range of sectors across society including health research, and science more broadly. == Definitions == An organisation called the Co-production Network for Wales describes co-production as "an asset-based approach to public services that enables people providing and people receiving services to share power and responsibility, and to work together in equal, reciprocal and caring relationships". According to Governance International, co-production is about "public service organisations and citizens making better use of each other's assets, resources and contributions". Co-production is designed to address real-world application of knowledge and forms part of what is termed Mode 2 of


id: co-production-approach-20260505-1
file: data/en.wikipedia.org/wiki/Co-production_(approach)-1.md
category: reference
title: Co-production (approach)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Co-production_(approach)
date_saved: 2026-05-05T10:02:06.033625+00:00
instance: kb-cron
parent: co-production-approach-20260505-0
summary:
=== Co-production of climate services === A disconnect exists between the climate information that is produced by science (in terms of weather forecasts and climate projections) and what is needed by users to make climate-resilient decisions. The mismatch usually relates to time scales, spatial scales, and metrics. Co-producing climate services, by bringing together producers and users of climate information for dialogue, can lead to the creation of new knowledge that is more appropriate for use in terms of being tailored and targeted to particular decisions. As in other fields, co-production of climate services, can create challenges due to differences in the incentives, priorities and languages of the various parties (often grouped into "producers" of information and "users" of information). Although there are no recipes for how to co-produce climate services, there are a number of building blocks and principles. == Concepts of co-production == Co-production is based on the production of own services and resources by citizens, completely or in part. It involves the willingness of citizens or users together with public services to design, implement and improve the delivery of services in order to innovate and transform public services. === Co-management === The concept of co-management implies the introduction


id: co-production-approach-20260505-2
file: data/en.wikipedia.org/wiki/Co-production_(approach)-2.md
category: reference
title: Co-production (approach)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Co-production_(approach)
date_saved: 2026-05-05T10:02:06.033625+00:00
instance: kb-cron
parent: co-production-approach-20260505-0
summary:
Funding and Commissioning: Commissioners of public money will need to change their established ways of doing things. Applying strict quantitative targets and stipulating rigid, short-term outputs with a mind to economic efficiency acts as a barrier to co-produced service models. In order to 'commission for change' narrow outputs need to be broadened and complemented by outcomes based commissioning. Generating evidence and making the case for co-production: The obvious reason why many commissioning frameworks favour outputs over outcomes is that they are simply measured, making it deceptively easy to evaluate success or failure. But real success is not easily measurable. Nor are many of the preventative benefits of co-production easy to quantify. Making the case for co-production and capturing its complex and myriad benefits is a key challenge. Taking successful approaches to scale: It is fair to say that the majority of examples where co-production is being successfully practiced take place at a local scale. To a great extent this has been instrumental to their success; they are rooted in local realities, have grown organically from the ground based on local assets and ideas and emphasise the importance of face-to-face relationships. There is a potential tension to be overcome here; ensuring


id: co-production-approach-20260505-3
file: data/en.wikipedia.org/wiki/Co-production_(approach)-3.md
category: reference
title: Co-production (approach)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Co-production_(approach)
date_saved: 2026-05-05T10:02:06.033625+00:00
instance: kb-cron
parent: co-production-approach-20260505-0
summary:
== Selected co-production bibliography == Alford, J. (1998), A public management road less traveled: clients as co-producers of public services. Australian Journal of Public Administration, 57 (4), 128-137. Alford, J. (2007), Engaging public sector clients: from service delivery to co-production. Houndmills, Basingstoke: Palgrave Macmillan. Barnes, M., Harrison, S., Mort, M., Shardlow, P. and Wistow G. (1999), 'The new management of community care: users groups, citizenship and co-production' in G.Stoker, New Management of British Local Governance. Houndmills: Macmillan. Tony Bovaird (2007), "Beyond engagement and participation – user and community co-production of public services", Public Administration Review, 67 (5): 846-860 (2007). Tony Bovaird and Elke Loeffler (2010), "User and community co-production of public services and public policies through collective decision-making: the role of emerging technologies" in T. Brandsen and Marc Holzer (Eds), The Future of Governance. Newark, NJ: National Center for Public Performance. Tony Bovaird and Elke Loeffler (2012), "From Engagement to Co-production: How Users and Communities Contribute to Public Services" in Taco Brandsen and Victor Pestoff (Eds), New Public Governance, the Third Sector and Co-Production. London: Routledge. Matthew Horne and Tom Shirley (2009), Co-production in public services: a new partnership with citizens. London: Cabinet Office. Roger Dunston, Alison Lee, David Boud,


id: community-engaged-research-20260505-0
file: data/en.wikipedia.org/wiki/Community-engaged_research-0.md
category: reference
title: Community-engaged research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Community-engaged_research
date_saved: 2026-05-05T10:02:07.181236+00:00
instance: kb-cron
parent: community-engaged-research-20260505-0
summary:
Community-engaged research (CEnR) is the process of working collaboratively with groups of people affiliated by geographic proximity, special interests, or similar situations with respect to issues affecting their well-being. One of the most widely used forms of community-engaged research is community-based participatory research (CBPR), though it also encompasses action research and participatory action research. Another form of community-engaged research is integrated knowledge translation (iKT), defined as "an approach to doing research that applies the principles of knowledge translation to the entire research process". The iKT evolves around the concept of engaging different levels of knowledge users (community members, organizations working in the community, and policy makers) as equal partners in the research activities so that research outputs are more relevant to, and more likely to be useful to, the knowledge users. == History == Community-engaged research arose in response to historical abuse of marginalized people by researchers, who failed to consider the needs of the community and potential benefits of the research. Types of CEnR include action research, community-based participatory research (CBPR), and participatory action research (PAR). The field of CEnR has grown rapidly since 2005. == Process == Community-engaged research is planned in partnership with the community that is


id: cross-sectional-study-20260505-0
file: data/en.wikipedia.org/wiki/Cross-sectional_study-0.md
category: reference
title: Cross-sectional study
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cross-sectional_study
date_saved: 2026-05-05T10:02:08.440904+00:00
instance: kb-cron
parent: cross-sectional-study-20260505-0
summary:
In medical research, epidemiology, social science, and biology, a cross-sectional study (also known as a cross-sectional analysis, transverse study, prevalence study) is a type of research design that analyzes data from a population, or a representative subset, at a specific point in time—that is, cross-sectional data. In economics, cross-sectional studies typically involve the use of cross-sectional regression, in order to sort out the existence and magnitude of causal effects of one independent variable upon a dependent variable of interest at a given point in time. They differ from time series analysis, in which the behavior of one or more economic aggregates is traced through time. In medical research, cross-sectional studies differ from case-control studies in that they aim to provide data on the entire population under study, whereas case-control studies typically include only individuals who have developed a specific condition and compare them with a matched sample, often a tiny minority, of the rest of the population. Cross-sectional studies are descriptive studies (neither longitudinal nor experimental). Unlike case-control studies, they can be used to describe, not only the odds ratio, but also absolute risks and relative risks from prevalences (sometimes called prevalence risk ratio, or PRR). They may be used


id: cross-sectional-study-20260505-1
file: data/en.wikipedia.org/wiki/Cross-sectional_study-1.md
category: reference
title: Cross-sectional study
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cross-sectional_study
date_saved: 2026-05-05T10:02:08.440904+00:00
instance: kb-cron
parent: cross-sectional-study-20260505-0
summary:
== Economics == In economics, cross-sectional analysis has the advantage of avoiding various complicating aspects of the use of data drawn from various points in time, such as serial correlation of residuals. It also has the advantage that the data analysis itself does not need an assumption that the nature of the relationships between variables is stable over time, though this comes at the cost of requiring caution if the results for one time period are to be assumed valid at some different point in time. An example of cross-sectional analysis in economics is the regression of money demand—the amounts that various people hold in highly liquid financial assets—at a particular time upon their income, total financial wealth, and various demographic factors. Each data point is for a particular individual or family, and the regression is conducted on a statistical sample drawn at one point in time from the entire population of individuals or families. In contrast, an intertemporal analysis of money demand would use data on an entire country's holdings of money at each of various points in time, and would regress that on contemporaneous (or near-contemporaneous) income, total financial wealth, and some measure of interest rates. The cross-sectional


id: cross-sequential-study-20260505-0
file: data/en.wikipedia.org/wiki/Cross-sequential_study-0.md
category: reference
title: Cross-sequential study
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cross-sequential_study
date_saved: 2026-05-05T10:02:09.630502+00:00
instance: kb-cron
parent: cross-sequential-study-20260505-0
summary:
A cross-sequential design is a research method that combines both a longitudinal design and a cross-sectional design. It aims to correct for some of the problems inherent in the cross-sectional and longitudinal designs. In a cross-sequential design (also called an "accelerated longitudinal" or "convergence" design), a researcher wants to study development over some large period of time within the lifespan. Rather than studying particular individuals across that whole period of time (e.g. 20–60 years) as in a longitudinal design, or multiple individuals of different ages at one time (e.g. 20, 25, 30, 35, 40, 45, 50, 55, and 60 years) as in a cross-sectional design, the researcher chooses a smaller time window (e.g. 20 years) to study multiple individuals of different starting ages. An example of a cross-sequential design is shown in the table below. In this table, over a span of 10 years, from 2000 to 2010, 7 overlapping cohorts with different starting ages could be studied to provide information on the whole span of development from ages 20 to 60. This design has been used in studies to investigate career trajectories in academia and other phenomena. == References ==


id: customer-foresight-20260505-0
file: data/en.wikipedia.org/wiki/Customer_foresight-0.md
category: reference
title: Customer foresight
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Customer_foresight
date_saved: 2026-05-05T10:02:10.845215+00:00
instance: kb-cron
parent: customer-foresight-20260505-0
summary:
Customer foresight is a new field of applied research. It aims to understand future consumer preferences and wishes with regard to tomorrow's products and services. It does so by combining customer research and foresight research elements. Customer foresight can be conceived as an interaction with projected future markets through selected customers by understanding their wishes and attitudes, ideas and visions as well as their perception of signals and drivers of change. Even though the concept cannot predict the future, it enables companies to prepare for different future scenarios and thus improves strategy and decision-making processes. == Definition and classification == As the future combines both continuity and change, not everything one knows today will disappear tomorrow. Some things will change significantly while others will not. But even today, research reveals that numerous inventions fail due to a lack of customer centricity. Consequently, anticipating future customer needs and behaviors constitutes a challenge when developing future product portfolios. This is especially relevant for industries with long planning cycles because these industries have to develop value propositions today for the customers of tomorrow. However, this involves dealing with many unknowns e.g. future everyday life or future consumption patterns. This is why, customer foresight


id: data-storage-tag-20260505-0
file: data/en.wikipedia.org/wiki/Data_storage_tag-0.md
category: reference
title: Data storage tag
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Data_storage_tag
date_saved: 2026-05-05T10:02:12.030778+00:00
instance: kb-cron
parent: data-storage-tag-20260505-0
summary:
A data storage tag (DST), also sometimes known as an archival tag, is a combination of a data logger and multiple sensors that record data at predetermined intervals. DSTs usually have a large memory size and a long lifetime: most are supported by batteries that allow the tag to record positions for several years. Alternatively some tags are solar powered and allow the scientist to set their own interval; this then allows data to be recorded for significantly longer than battery-only powered tags. == Operation == Data storage tags can have a variety of sensors; temperature, depth, light, salinity, pressure, pitch and roll, GPS, magnetic and compass. They can be used internally or externally in fish, marine animals or research animals. They are also used in other industries such as the food and beverage industry. At the end of the monitoring period, the loggers can be connected to a computer and the data uploaded for analysis. Data collected by data storage tags can be used to infer locations of the animal when it is at large. == Deployment == Archival tags archive data to internal memory. Once they are recovered the data is then extracted by the researcher. The tag


id: design-science-20260505-0
file: data/en.wikipedia.org/wiki/Design_science-0.md
category: reference
title: Design science
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Design_science
date_saved: 2026-05-05T10:02:13.249584+00:00
instance: kb-cron
parent: design-science-20260505-0
summary:
Design science refers to a scientific, i.e. rational and systematic, approach to designing. An early concept of design science was introduced in 1957 by R. Buckminster Fuller who defined it as a systematic form of designing which he applied especially in innovative engineering design. The concept has been more broadly defined by the Design Science journal as “quantitative and qualitative research in the creation of artifacts and systems, and their embedding in our physical, virtual, psychological, economic, and social environment”. == Design-science relationship == There has been recurrent concern to differentiate design from science. Nigel Cross differentiated between scientific design, design science and a science of design. A science of design (the scientific study of design) does not require or assume that the acts of designing are themselves scientific, and an increasing number of research programs take this view. To some extent the two uses of the term design science (systematic designing and the study of designing) have co-mingled to the point where there can be some confusion, and design science sometimes may be referred to either as meaning a science of design or design as a science. == A science of design == Herbert A. Simon's The Sciences of


id: design-science-methodology-20260505-0
file: data/en.wikipedia.org/wiki/Design_science_(methodology)-0.md
category: reference
title: Design science (methodology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Design_science_(methodology)
date_saved: 2026-05-05T10:02:14.418805+00:00
instance: kb-cron
parent: design-science-methodology-20260505-0
summary:
Design science research (DSR) is a research paradigm focusing on the development and validation of prescriptive knowledge in information science. Herbert Simon distinguished the natural sciences, concerned with explaining how things are, from design sciences which are concerned with how things ought to be, that is, with devising artifacts to attain goals. Design science research methodology (DSRM) refers to the research methodologies associated with this paradigm. It spans the methodologies of several research disciplines, for example information technology, which offers specific guidelines for evaluation and iteration within research projects. DSR focuses on the development and performance of (designed) artifacts with the explicit intention of improving the functional performance of the artifact. DSRM is typically applied to categories of artifacts including algorithms, human/computer interfaces, design methodologies (including process models) and languages. Its application is most notable in the Engineering and Computer Science disciplines, though is not restricted to these and can be found in many disciplines and fields. DSR, or constructive research, in contrast to explanatory science research, has academic research objectives generally of a more pragmatic nature. Research in these disciplines can be seen as a quest for understanding and improving human performance. Such renowned research institutions as the MIT


id: design-science-methodology-20260505-1
file: data/en.wikipedia.org/wiki/Design_science_(methodology)-1.md
category: reference
title: Design science (methodology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Design_science_(methodology)
date_saved: 2026-05-05T10:02:14.418805+00:00
instance: kb-cron
parent: design-science-methodology-20260505-0
summary:
Artifacts within DSR are perceived to be knowledge containing. This knowledge ranges from the design logic, construction methods and tool to assumptions about the context in which the artifact is intended to function (Gregor, 2002). The creation and evaluation of artifacts thus forms an important part in the DSR process which was described by Hevner et al., (2004) and supported by March and Storey (2008) as revolving around “build and evaluate”. DSR artifacts can broadly include: models, methods, constructs, instantiations and design theories (March & Smith, 1995; Gregor 2002; March & Storey, 2008, Gregor and Hevner 2013), social innovations, new or previously unknown properties of technical/social/informational resources (March, Storey, 2008), new explanatory theories, new design and developments models and implementation processes or methods (Ellis & Levy 2010). == A three-cycle view == DSR can be seen as an embodiment of three closely related cycles of activities. The relevance cycle initiates DSR with an application context that not only provides the requirements for the research as inputs but also defines acceptance criteria for the ultimate evaluation of the research results. The rigor cycle provides past knowledge to the research project to ensure its innovation. It is incumbent upon the researchers to


id: design-based-research-20260505-0
file: data/en.wikipedia.org/wiki/Design-based_research-0.md
category: reference
title: Design-based research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Design-based_research
date_saved: 2026-05-05T10:02:15.526914+00:00
instance: kb-cron
parent: design-based-research-20260505-0
summary:
Design-based research (DBR) is a type of research methodology used by researchers in the learning sciences, which is a sub-field of education. The basic process of DBR involves developing solutions (called "interventions") to problems. Then, the interventions are put to use to test how well they work. The iterations may then be adapted and re-tested to gather more data. The purpose of this approach is to generate new theories and frameworks for conceptualizing learning, instruction, design processes, and educational reform. Data analysis often takes the form of iterative comparisons. == Role within the learning sciences == Methodologically, the learning sciences differs from other fields in educational research. It focuses on the study of learners, their localities, and their communities. The design-based research methodology is often used by learning scientists in their inquiries because this methodological framework considers the subject of study to be a complex system involving emergent properties that arise from the interaction of more variables than are initially known to researchers, including variables stemming from the researchers themselves (Brown, 1992). Rather than attempting to isolate all the various factors that impact learning as in traditional research, the learning sciences employ design based research methodologies which appeal to an


id: electric-cell-substrate-impedance-sensing-20260505-0
file: data/en.wikipedia.org/wiki/Electric_cell-substrate_impedance_sensing-0.md
category: reference
title: Electric cell-substrate impedance sensing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electric_cell-substrate_impedance_sensing
date_saved: 2026-05-05T10:02:16.654964+00:00
instance: kb-cron
parent: electric-cell-substrate-impedance-sensing-20260505-0
summary:
Electric cell-substrate impedance sensing or ECIS (a trademark of Applied BioPhysics Inc.) refers to a non-invasive biophysical approach to monitor living animal cells in vitro, i.e. within a well-defined laboratory environment. In ECIS the cells are grown on the surface of small and planar gold-film electrodes, which are deposited on the bottom of a cell culture dish (Petri dish). The AC impedance of the cell-covered electrode is then measured at one or several frequencies as a function of time. Due to the insulating properties of their membranes the cells behave like dielectric particles so that the impedance increases with increasing coverage of the electrode until a confluent (i.e. continuous) layer of cells is established. In confluent cell layers the measured impedance is mainly determined by the three-dimensional shape of the cells. If cell shape changes occur, the current pathways through and around the cell bodies change as well, leading to a corresponding increase or decrease of impedance. Thus, by recording time-resolved impedance measurements, cell shape changes can be followed in real time with sub-microscopic resolution and can be used for bioanalytic purposes. As the shape of animal cells responds very sensitively to alterations in metabolism as well as chemical, biological


id: field-trip-20260505-0
file: data/en.wikipedia.org/wiki/Field_trip-0.md
category: reference
title: Field trip
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Field_trip
date_saved: 2026-05-05T10:02:17.862922+00:00
instance: kb-cron
parent: field-trip-20260505-0
summary:
A field trip or excursion is a journey by a group of associated peers, such as coworkers or school students, to a place away from their normal environment for the purpose of education or leisure, either within their country or abroad. When arranged by a school administration for students, it is also known as school trip in the United Kingdom, Australia, Kenya, New Zealand and Bangladesh, and school tour in Ireland. A 2022 study, which used randomized controlled trial data, found that culturally enriching field trips led students to show a greater interest in arts, greater tolerance for people with different views, and boosted their educational outcomes. == Overview == The purpose of the field trip is usually observation for education, non-experimental research or to provide students with experiences outside their everyday activities, such as going camping with teachers and their classmates. The aim of this research is to observe the subject in its natural state and possibly collect samples. It is seen that more-advantaged children may have already experienced cultural institutions outside of school, and field trips provide common ground between more-advantaged and less-advantaged children to share the same cultural experiences. Field trips often involve three steps: preparation, activities


id: force-matching-20260505-0
file: data/en.wikipedia.org/wiki/Force_matching-0.md
category: reference
title: Force matching
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Force_matching
date_saved: 2026-05-05T10:02:19.049219+00:00
instance: kb-cron
parent: force-matching-20260505-0
summary:
Force matching is a research method consisting of test subjects attempting to produce a set forces that are equal to a set of more reliable reference forces. == Types == === Biomechanical === A subject’s maximum voluntary contraction (MVC) is recorded and used to normalize both reference forces and results between subjects. During the test subjects are assisted in producing a reference force using various types of feedback (static weight or visual display of force generated). This is followed by an attempt of the subject to generate the reference force without assistance. The duration for both reference and matching tasks is usually four seconds. Results are taken as a mean value of force generated over a time interval set by the researcher. Time intervals are generally one second long and near the end of the attempt. Reference forces are typically set as a percentage of a subject’s MVC while error is typically reported as a percentage of a subject’s MVC. === Atomic === It is one of the effective research method to obtain realistic classical interatomic potential or force field for molecular dynamics simulation with high degree of transferability for systems which the first principles or ab initio method is


id: frascati-manual-20260505-0
file: data/en.wikipedia.org/wiki/Frascati_Manual-0.md
category: reference
title: Frascati Manual
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Frascati_Manual
date_saved: 2026-05-05T10:02:20.224055+00:00
instance: kb-cron
parent: frascati-manual-20260505-0
summary:
The Frascati Manual is a document setting forth the methodology for collecting statistics about research and development. The Manual was prepared and published by the Organisation for Economic Co-operation and Development. == Contents == The Frascati Manual classifies budgets according to what is done, what is studied, and who is studying it. For example, an oral history project conducted by a religious organization would be classified as being basic research, in the field of humanities (the sub-category of history), and performed by a non-governmental, non-profit organization. === Three forms of research === The manual gives definitions for: basic research, applied research, Research and development; research personnel: researchers, technicians, auxiliary personnel. The Frascati Manual classifies research into three categories: Basic research is experimental or theoretical work undertaken primarily to acquire new knowledge of the underlying foundations of phenomena and observable facts, without any particular application or use in view. Applied research is original investigation undertaken in order to acquire new knowledge. It is, however, directed primarily towards a specific, practical aim or objective. Experimental development is systematic work, drawing on knowledge gained from research and practical experience and producing additional knowledge, which is directed to producing new products or processes or


id: grounded-theory-20260505-0
file: data/en.wikipedia.org/wiki/Grounded_theory-0.md
category: reference
title: Grounded theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Grounded_theory
date_saved: 2026-05-05T10:02:21.462775+00:00
instance: kb-cron
parent: grounded-theory-20260505-0
summary:
Grounded theory is a systematic methodology that has been largely applied to qualitative research conducted by social scientists. The methodology involves the construction of hypotheses and theories through the analysis of data and inductive reasoning. The methodology contrasts with the hypothetico-deductive model used in traditional scientific research. A study based on grounded theory is likely to begin with a question, or even just with the collection of qualitative data. As researchers review the data collected, ideas or concepts become apparent to the researchers. These ideas/concepts are said to "emerge" from the data. The researchers tag those ideas/concepts with codes that succinctly summarize the ideas/concepts. As more data are collected and re-reviewed, codes can be grouped into higher-level concepts and then into categories. These categories become the basis of a hypothesis or a new theory. Thus, grounded theory is quite different from the traditional scientific model of research, where the researcher chooses an existing theoretical framework, develops one or more hypotheses derived from that framework, and only then collects data for the purpose of assessing the validity of the hypotheses. == Background == Grounded theory is a general research methodology, a way of thinking about and conceptualizing data. It is used


id: grounded-theory-20260505-1
file: data/en.wikipedia.org/wiki/Grounded_theory-1.md
category: reference
title: Grounded theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Grounded_theory
date_saved: 2026-05-05T10:02:21.462775+00:00
instance: kb-cron
parent: grounded-theory-20260505-0
summary:
== Premise == Grounded theory provides methods for generating hypotheses from qualitative data. After hypotheses are generated, it is up to other researchers to attempt to sustain or reject those hypotheses. Questions asked by the qualitative researcher employing grounded theory include "What is going on?" and "What is the main problem of the participants, and how are they trying to solve it?" Researchers using grounded theory methods do not aim for the "truth." Rather, those researchers try to conceptualize what has been taking place in the lives of study participants. When applying grounded theory methods, the researcher does not formulate hypotheses in advance of data collection as is often the case in traditional research, otherwise the hypotheses would be ungrounded in the data. Hypotheses are supposed to emerge from the data. A goal of the researcher employing grounded theory methods is that of generating concepts that explain the way people resolve their central concerns regardless of time and place. These concepts organize the ground-level data. The concepts become the building blocks of hypotheses. The hypotheses become the constituents of a theory. In most behavioral research endeavors, persons or patients are units of analysis, whereas in grounded theory the unit of


id: grounded-theory-20260505-2
file: data/en.wikipedia.org/wiki/Grounded_theory-2.md
category: reference
title: Grounded theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Grounded_theory
date_saved: 2026-05-05T10:02:21.462775+00:00
instance: kb-cron
parent: grounded-theory-20260505-0
summary:
=== Coding === Coding places incidents into categories and then creates one or more hierarchies out of these categories in terms of categories and subcategories or properties of a categories. A property might be on a continuum such as from low to high, this may be referred to as a dimension. Constant comparison where categories are continually compared to one another is used to create both subcategories and properties. There is some variation in the meanings of the terms code, concept and category with some authors viewing a code as identical to category while others consider a concept to be more abstract than a code, which a code being more like a substantive code. Different researchers have identified different types of codes and encourage different methods of coding, with Strauss and Glaser both going on to extend their work with different forms of coding. The core variable explains most of the participants' main concern with as much variation as possible. It has the most powerful properties to picture what's going on, but with as few properties as possible needed to do so. A popular type of core variable can be theoretically modeled as a basic social process that accounts for


id: grounded-theory-20260505-3
file: data/en.wikipedia.org/wiki/Grounded_theory-3.md
category: reference
title: Grounded theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Grounded_theory
date_saved: 2026-05-05T10:02:21.462775+00:00
instance: kb-cron
parent: grounded-theory-20260505-0
summary:
=== Serendipity pattern === Building on the work of sociologist Robert K. Merton, his idea of serendipity patterns has come to be applied in grounded theory research. Serendipity patterns refer to fairly common experiences when observing the world. Serendipity patterns include unanticipated and anomalous events. These patterns can become the impetus for the development of a new theory or the extension of an existing theory. Merton also coauthored (with Elinor Barber) The Travels and Adventures of Serendipity, which traces the origins and uses of the word "serendipity" since it was coined. The book is "a study in sociological semantics and the sociology of science," as the subtitle declares. Merton and Barber further develop the idea of serendipity as scientific "method," as contrasted with purposeful discovery by experiment or retrospective prophecy. === Sorting === In the next step memos are sorted, which is the key to formulating a theory that could be clearly presented to others. Sorting puts fractured data back together. During sorting new ideas can emerge. The new ideas can, in turn, be recorded in new memos, giving rise to the memo-on-memos phenomenon. Sorting memos can help generate theory that explains the main action in the studied area. A


id: grounded-theory-20260505-4
file: data/en.wikipedia.org/wiki/Grounded_theory-4.md
category: reference
title: Grounded theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Grounded_theory
date_saved: 2026-05-05T10:02:21.462775+00:00
instance: kb-cron
parent: grounded-theory-20260505-0
summary:
=== Constructivist grounded theory === A later version of grounded theory called constructivist grounded theory, which is rooted in pragmatism and constructivist epistemology, assumes that neither data nor theories are discovered, but are constructed by researchers as a result of their interactions with the field and study participants. Proponents of this approach include Kathy Charmaz and Antony Bryant. In an interview, Charmaz justified her approach as follows: "Grounded theory methodology had been under attack. The postmodern critique of qualitative research had weakened its legitimacy and narrative analysts criticized grounded theory methodology for fragmenting participants' stories. Hence, grounded theory methodology was beginning to be seen as a dated methodology and some researchers advocated abandoning it. I agreed with much of the epistemological critique of the early versions of grounded theory methodology by people like Kenneth Gergen. However, I had long thought that the strategies of grounded theory methodology, including coding, memo writing, and theoretical sampling were excellent methodological tools. I saw no reason to discard these tools and every reason to shift the epistemological grounds on which researchers used them." Data are co-constructed by the researcher and study participants, and colored by the researcher's perspectives, values, privileges, positions, interactions, and geographical


id: grounded-theory-20260505-5
file: data/en.wikipedia.org/wiki/Grounded_theory-5.md
category: reference
title: Grounded theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Grounded_theory
date_saved: 2026-05-05T10:02:21.462775+00:00
instance: kb-cron
parent: grounded-theory-20260505-0
summary:
== Criticisms == Grounded theory has been criticized based on the scientific idea of what a theory is. Thomas and James, for example, distinguish the ideas of generalization, overgeneralization, and theory, noting that some scientific theories explain a broad range of phenomena succinctly, which grounded theory does not. Thomas and James observed that "The problems come when too much is claimed for [for a theory], simply because it is empirical; problems come in distinguishing generalization from over-generalization, narrative from induction." They also write that grounded theory advocates sometimes claim to find causal implications when in truth they only find an association. There has been criticism of grounded theory on the grounds that it opens the door to letting too much researcher subjectivity enter. The authors just cited suggest that it is impossible to free oneself of preconceptions in the collection and analysis of data in the way that Glaser and Strauss assert is necessary. Popper also undermines grounded theory's idea that hypotheses arise from data unaffected by prior expectations. Popper wrote that "objects can be classified and can become similar or dissimilar, only in this way--by being related to needs and interests." Observation is always selective, based on past research


id: grounded-theory-20260505-6
file: data/en.wikipedia.org/wiki/Grounded_theory-6.md
category: reference
title: Grounded theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Grounded_theory
date_saved: 2026-05-05T10:02:21.462775+00:00
instance: kb-cron
parent: grounded-theory-20260505-0
summary:
== Further reading == Bryant, A. & Charmaz, K. (Eds.) (2007) The SAGE Handbook of Grounded Theory. Los Angeles: Sage. Birks, M. & Mills, J. (2015) Grounded Theory: A practical Guide. London: SAGE Publications. Charmaz, K. (2000). Constructing Grounded Theory: A Practical Guide Through Qualitative Analysis. Thousand Oaks, CA: Sage Publications. Chun Tie, Ylona, Birks, Melanie, and Francis, Karen (2019) Grounded theory research: a design framework for novice researchers. SAGE Open Medicine, 7. pp. 1–8. Clarke, A. (2005). Situational Analysis: Grounded Theory After the Postmodern Turn. Thousand Oaks, CA: Sage Publications. Glaser, B. (1992). Basics of grounded theory analysis. Mill Valley, CA: Sociology Press. Goulding, C. (2002). Grounded Theory: A Practical Guide for Management, Business and Market Researchers. London: Sage. Kelle, Udo (2005). "Emergence" vs. "Forcing" of Empirical Data? A Crucial Problem of "Grounded Theory" Reconsidered. Forum Qualitative Sozialforschung / Forum: Qualitative Social Research [On-line Journal], 6(2), Art. 27, paragraphs 49 & 50. [2] Morse, J. M., Stern, P. N., Corbin, J., Bowers, B., Charmaz, K. & Clarke, A. E. (Eds.) (2009). Developing Grounded Theory: The Second Generation. Walnut Creek: Left Coast Press. Mey, G. & Mruck, K. (Eds.) (2007). Grounded Theory Reader. Historical Social Research, Suppl. 19. 337 pages.


id: health-risk-assessment-20260505-0
file: data/en.wikipedia.org/wiki/Health_risk_assessment-0.md
category: reference
title: Health risk assessment
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Health_risk_assessment
date_saved: 2026-05-05T10:02:22.671106+00:00
instance: kb-cron
parent: health-risk-assessment-20260505-0
summary:
A health risk assessment (also referred to as a health risk appraisal and health & well-being assessment) is a questionnaire about a person's medical history, demographic characteristics and lifestyle. It is one of the most widely used screening tools in the field of health promotion and is often the first step in multi-component health promotion programs. == Definition == A health risk assessment (HRA) is a health questionnaire, used to provide individuals with an evaluation of their health risks and quality of life. Commonly a HRA incorporates three key elements – an extended questionnaire, a risk calculation or score, and some form of feedback, i.e. face-to-face with a health advisor or an automatic online report. The Centers for Disease Control and Prevention define a HRA as: "a systematic approach to collecting information from individuals that identifies risk factors, provides individualised feedback, and links the person with at least one intervention to promote health, sustain function and/or prevent disease". There is a range of different HRAs available for adults and children. Some target specific populations. For example, in the US, Medicare HRAs ask seniors about their ability to perform daily activities. Medicaid assessments ask questions about health-care access, availability of food,


id: health-risk-assessment-20260505-1
file: data/en.wikipedia.org/wiki/Health_risk_assessment-1.md
category: reference
title: Health risk assessment
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Health_risk_assessment
date_saved: 2026-05-05T10:02:22.671106+00:00
instance: kb-cron
parent: health-risk-assessment-20260505-0
summary:
== History == The original concept of the HRA can be traced back to the decision by the assistant Surgeon General of the United States to conduct a study to determine the probable 10-year lifespan of individuals based on lifestyles and predisposed conditions. The project, led by Lewis C. Robbins, MD, of the Public Health Service, was the Framingham study. The study was based on in-depth longitudinal studies of 5,000 families in Framingham, Massachusetts, that continues to this day under funding from the National Institutes of Health. Dr. Robbins left the Public Health Service and joined Methodist Hospital in Indianapolis where, working with Jack Hall, M.D., he developed the first set of health hazard tables. This culminated in the publication of How to Practice Prospective Medicine in 1970 – a guide for practising physicians, which outlined the health risk assessment questionnaire, risk computations and patient feedback strategies. During the 1960s, some researchers in California formed the Human Population Laboratory (HPL) to investigate factors contributing to quality of life. Inspired by a research article reporting on the HPL's Alameda County Study on the best lifestyle practices for good health, Don R. Hall, DrPH, developed a Health Age Assessment algorithm on a


id: implementation-research-20260505-0
file: data/en.wikipedia.org/wiki/Implementation_research-0.md
category: reference
title: Implementation research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Implementation_research
date_saved: 2026-05-05T10:02:23.878384+00:00
instance: kb-cron
parent: implementation-research-20260505-0
summary:
Implementation research is the systematic study of methods that support the application of research findings and other evidence-based knowledge into policy and practice. It aims to understand the most effective pathways from research to practical application, particularly in areas such as health, education, psychology and management. Intervention research, also known as intervention science, evaluates how various interventions or approaches are adopted and applied in "real world" settings in order to establish an understanding of their effectiveness in different contexts. == Public health == In the context of public health, the World Health Organization (WHO) describes implementation research as a form of research which "addresses implementation bottlenecks, identifies optimal approaches for a particular setting, and promotes the uptake of research findings: ultimately, it leads to improved health care and its delivery." The WHO identifies four notable characteristics of implementation research: it is systematic, multidisciplinary, contextual, and complex. More broadly, implementation research has been defined as "the scientific inquiry into questions concerning implementation – the act of carrying an intention into effect, which in health research can be policies, programmes, or individual practices (collectively called interventions)." To guide, understand, and evaluate the implementation of these interventions in a systematic way, public health


id: incompatibility-thesis-20260505-0
file: data/en.wikipedia.org/wiki/Incompatibility_thesis-0.md
category: reference
title: Incompatibility thesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Incompatibility_thesis
date_saved: 2026-05-05T10:02:25.084785+00:00
instance: kb-cron
parent: incompatibility-thesis-20260505-0
summary:
Incompatibility thesis is an argument in research methodology about incompatibility of quantitative research and qualitative research paradigms in the same research. This thesis is based on philosophies of post-structuralism and post-modernism (among others). Arguments from those philosophies support exclusive superiority of one orientation (usually, the qualitative one) are oppose mixing it with quantitative research (as is advocated by the proponents of mixed-method research who support the compatibility thesis). == Information == Incompatibilists maintain that problems arise not so much at the level of practice, but at the level of epistemological paradigms. In particular, they propose that quantitative and qualitative methods are incompatible on an epistemological level; therefore, the two kinds of methods are incompatible. HOWE 1998, argues that a principle implicit in the incompatibilist's argument ‘that abstract paradigms should determine research methods in a one-way fashion—is untenable’. That paradigms must demonstrate their worth in terms of how they inform, and are informed by, research methods that are successfully employed. Given such a two-way relationship between methods and paradigms, paradigms are evaluated in terms of how well they square with the demands of research practice and incompatibilism vanishes. == References == Onwuegbuzie, Anthony J.; Leech, Nancy L. (2005). "Taking the "Q"


id: indicator-statistics-20260505-0
file: data/en.wikipedia.org/wiki/Indicator_(statistics)-0.md
category: reference
title: Indicator (statistics)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Indicator_(statistics)
date_saved: 2026-05-05T10:02:26.271833+00:00
instance: kb-cron
parent: indicator-statistics-20260505-0
summary:
In statistics and research design, an indicator is an observed value of a variable, or in other words "a sign of a presence or absence of the concept being studied". Just like each color indicates in a traffic lights the change in the movement. For example, if a variable is religiosity, and a unit of analysis is an individual, then that one of potentially more numerous indicators of that individual's religiosity would be whether they attend religious services; others - how often, or whether they donate money to religious organizations. Numerous indicators can be aggregated into an index. The complexity of biological systems makes evaluating them a challenge. Bioindicators, such as indicator bacteria, are ecological indicators, sometimes requiring further consideration of environmental indicators. In public health study, one relies on health indicators. In a given locality, community indicators inform planners, while the design quality indicator can be the basis of building permits. Assessment of social conditions relies on sustainability indicators or the genuine progress indicator. Standard measurements are given in the OECD Main Economic Indicators. A famous popular science individual psychological assessment is the Myers–Briggs Type Indicator. == References ==


id: infoq-20260505-0
file: data/en.wikipedia.org/wiki/InfoQ-0.md
category: reference
title: InfoQ
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/InfoQ
date_saved: 2026-05-05T10:02:27.431143+00:00
instance: kb-cron
parent: infoq-20260505-0
summary:
Information quality (InfoQ) is the extent to which a data set can help achieve a specific scientific or practical goal when it is used with a particular empirical analysis method. == Definition == InfoQ is often expressed as InfoQ = U(X,f|g), where X is the data, f is the analysis method, g is the goal, and U is the utility function. In simpler terms, it describes how useful a given set of data is for answering a particular question with a particular method. InfoQ is related to both data quality and analysis quality, but it is not the same as either one; it depends on the quality of the data, the suitability of the analysis, and how well the data, method, and goal fit together. InfoQ has been applied in fields including healthcare, customer surveys, data science programmes, advanced manufacturing, and Bayesian network applications. Kenett and Shmueli (2014) proposed eight dimensions to help assess InfoQ and various methods for increasing InfoQ: data resolution, data structure, data integration, temporal relevance, chronology of data and goal, generalization, operationalization, and communication. == References ==


id: intermediated-research-20260505-0
file: data/en.wikipedia.org/wiki/Intermediated_research-0.md
category: reference
title: Intermediated research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Intermediated_research
date_saved: 2026-05-05T10:02:28.622602+00:00
instance: kb-cron
parent: intermediated-research-20260505-0
summary:
In finance, intermediated research is a type of fundamental analysis or investment analysis of a business to establish its value for investors that attempts to avoid commercial pressure or influence. Many banks and brokers provide research to the investment community, however this form of research suffers from a real or perceived lack of objectivity. For example, this research may be subject to influence from within a bank from, say, investment bankers keen to win company’s IPO mandate. An alternative form is known as independent research or alternative research, this is research that is not provided by a bank or broker. However, someone has to fund the costs of conducting the research, and when the funder is the company being researched, this form of independent research is termed “sponsored” or “company-paid” research. Unfortunately, with the subject company paying directly for these services, this form of research suffers from a real or perceived lack of objectivity, which reduces its value to investors and hence to the companies themselves. Intermediated research improves significantly upon the sponsored research model, by introducing important safeguards into the commercial and research process framework. The key structure is that the company has no choice in its allocation to


id: literature-review-20260505-0
file: data/en.wikipedia.org/wiki/Literature_review-0.md
category: reference
title: Literature review
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Literature_review
date_saved: 2026-05-05T10:02:29.835558+00:00
instance: kb-cron
parent: literature-review-20260505-0
summary:
A literature review is an overview of previously published works on a particular topic. The term can refer to a full scholarly paper or a section of a scholarly work such as books or articles. Either way, a literature review provides the researcher/author and the audiences with general information of an existing knowledge of a particular topic. A good literature review has a proper research question, a proper theoretical framework, and/or a chosen research method. It serves to situate the current study within the body of the relevant literature and provides context for the reader. In such cases, the review usually precedes the methodology and results sections of the work. Producing a literature review is often part of a graduate and post-graduate requirement, included in the preparation of a thesis, dissertation, or a journal article. Literature reviews are also common in a research proposal or prospectus (the document approved before a student formally begins a dissertation or thesis). A literature review can be a type of a review article. In this sense, it is a scholarly paper that presents the current knowledge including substantive findings as well as theoretical and methodological contributions to a particular topic. Literature reviews are secondary


id: longitudinal-study-20260505-0
file: data/en.wikipedia.org/wiki/Longitudinal_study-0.md
category: reference
title: Longitudinal study
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Longitudinal_study
date_saved: 2026-05-05T10:02:31.046324+00:00
instance: kb-cron
parent: longitudinal-study-20260505-0
summary:
A longitudinal study (or longitudinal survey, or panel study) is a research design that involves repeated observations of the same variables (e.g., people) over long periods of time (i.e., uses longitudinal data). It is often a type of observational study, although it can also be structured as longitudinal randomized experiment. Longitudinal studies are often used in social-personality and clinical psychology, to study rapid fluctuations in behaviors, thoughts, and emotions from moment to moment or day to day; in developmental psychology, to study developmental trends across the life span; and in sociology, to study life events throughout lifetimes or generations; and in consumer research and political polling to study consumer trends. The reason for this is that, unlike cross-sectional studies, in which different individuals with the same characteristics are compared, longitudinal studies track the same people, and so the differences observed in those people are less likely to be the result of cultural differences across generations, that is, the cohort effect. Longitudinal studies thus make observing changes more accurate and are applied in various other fields. In medicine, the design is used to uncover predictors of certain diseases. In advertising, the design is used to identify the changes that advertising has


id: massive-online-open-research-20260505-0
file: data/en.wikipedia.org/wiki/Massive_online_open_research-0.md
category: reference
title: Massive online open research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Massive_online_open_research
date_saved: 2026-05-05T10:02:32.161019+00:00
instance: kb-cron
parent: massive-online-open-research-20260505-0
summary:
Massive online open research (MOOR) is an online research and development (R&D) open access platform or higher education study program aiming at unlimited participation via the internet. It may be used to create, on a very large participative scale, a new discovery, development or creation which will be allegedly accompanied by a peer-review publication. == As a higher education online research program == In September 2013, The University of California in San Diego bioinformatics department, proposed a massive online open course which would feature "an opportunity (for students) to work on specific research projects under the leadership of prominent bioinformatics scientists". == As an online internet platform == Several internet platforms have shown their interest in bridging prominent science, technology, engineering and mathematics (i.e., STEM fields) researchers with students, as means to accelerate STEM discoveries and education. The internet social network Research Gate has unveiled that multiple discoveries and advancements in science have been made collaboratively in an open access scheme since its creation, essentially serving as a MOOR platform. The University of Amsterdam has been developing an online tool for massive online open research since February 2014. This tool will primarily focus on collaborative (qualitative) data analysis. == See


id: megastudy-20260505-0
file: data/en.wikipedia.org/wiki/Megastudy-0.md
category: reference
title: Megastudy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Megastudy
date_saved: 2026-05-05T10:02:33.313578+00:00
instance: kb-cron
parent: megastudy-20260505-0
summary:
A megastudy or mega-study is a research study in which a large number of different treatments or interventions are tested at the same time, on the same sample or similar samples, using a common outcome measure, and using the same experimental protocol. == Megastudy examples == Exercise encouragement Vaccination nudges Strengthening of democratic attitudes Interventions against climate change == Many-lab studies == The megastudy technique can be combined with the many-labs approach, so that teams of researchers from across the planet conduct the same experiment locally. == Megastudy criticisms == Statistical power: While the overall megastudy sample size may be large, the sample size per intervention may be relatively small, leading to underpowered designs with wide confidence intervals. As a result, while interventions may be comparable, their relative ranking by outcome measure may be noisy. Increased sample size can help address this issue. Lack of theory: The megastudy technique may be considered a form of "fishing expedition" for what interventions have strongest effect on the outcome measure, without much theory building. == References ==


id: methods-in-molecular-biology-20260505-0
file: data/en.wikipedia.org/wiki/Methods_in_Molecular_Biology-0.md
category: reference
title: Methods in Molecular Biology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Methods_in_Molecular_Biology
date_saved: 2026-05-05T10:02:34.484979+00:00
instance: kb-cron
parent: methods-in-molecular-biology-20260505-0
summary:
Methods in Molecular Biology is a book series published by Humana Press (an imprint of Springer Science+Business Media) that covers molecular biology research methods and protocols. The book series was introduced by series editor John M. Walker in 1983 and provides step-by-step instructions for carrying out experiments in a research lab. As of January 2020, more than 2000 volumes (2737 as of 15-August-2023) had been published in the series. The protocols are also available online in SpringerLink, and were previously in Springer Protocols. Each protocol opens with an introductory overview and a list of the materials and reagents needed to complete the experiment. Every protocol is followed by a detailed procedure that is supported with a notes section offering tips and "tricks of the trade" as well as troubleshooting advice. == See also == Biological Procedures Online == References == == External links == Official website


id: microphysiometry-20260505-0
file: data/en.wikipedia.org/wiki/Microphysiometry-0.md
category: reference
title: Microphysiometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Microphysiometry
date_saved: 2026-05-05T10:02:35.668394+00:00
instance: kb-cron
parent: microphysiometry-20260505-0
summary:
Microphysiometry is the in vitro micro-measurement of the functions and activities of life or of living matter (as organs, tissues, or cells) and of the physical and chemical phenomena involved on a very small micrometer (μm) scale. The term microphysiometry emerged in the scientific literature at the end of the 1980s. The primary parameters assessed in microphysiometry comprise pH and the concentration of dissolved oxygen, glucose, and lactic acid, with an emphasis on the first two. Measuring these parameters experimentally in combination with a fluidic system for cell culture maintenance and a defined application of drugs or toxins provides three quantitative output parameters: extracellular acidification rates (EAR), oxygen uptake rates (OUR), and rates of glucose consumption or lactate release that characterize the metabolic situation. Due to the label-free nature of sensor-based measurements, dynamic monitoring of cells or tissues for several days or even longer is feasible. On an extended timescale, a dynamic analysis of a cell's metabolic response to an experimental treatment can distinguish acute effects (e.g., one hour after a treatment), early effects (e.g., at 24 hours), and delayed, chronic responses (e.g., at 96 hours). As stated by Alajoki et al., "The concept is that it is possible to


id: model-for-assessment-of-telemedicine-20260505-0
file: data/en.wikipedia.org/wiki/Model_for_assessment_of_telemedicine-0.md
category: reference
title: Model for assessment of telemedicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Model_for_assessment_of_telemedicine
date_saved: 2026-05-05T10:02:36.828432+00:00
instance: kb-cron
parent: model-for-assessment-of-telemedicine-20260505-0
summary:
Model for assessment of telemedicine (MAST) is a framework for assessment of the value of telemedicine. == Description == Telemedicine services may have many different types of outcomes and can be studied in many ways. In order for those who develop new telemedicine services to produce the information that healthcare managers need for making decisions on investment in telemedicine, a model for assessment of telemedicine (MAST) was developed. This work was done in 2010 through stakeholder workshops and on the basis of a systematic literature review. If the goal of evaluating telemedicine applications is to assess their effectiveness and impact on the quality of care, and to provide a foundation for decision-making, then according to MAST, the appropriate assessment framework is a multidisciplinary process. This process involves summarizing and evaluating information concerning medical, social, economic, and ethical considerations related to telemedicine in a systematic, impartial, and rigorous manner. This statement is based on the definition of Health technology assessment (HTA) in the EUnetHTA project. Key concepts are "multidisciplinary" and "systematic, unbiased and robust". The first concept implies that the assessments should include all important outcomes of the applications for patients, clinicians, healthcare institutions and society in general. The others imply


id: motion-analysis-20260505-0
file: data/en.wikipedia.org/wiki/Motion_analysis-0.md
category: reference
title: Motion analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Motion_analysis
date_saved: 2026-05-05T10:02:38.023893+00:00
instance: kb-cron
parent: motion-analysis-20260505-0
summary:
Motion analysis is used in computer vision, image processing, high-speed photography and machine vision that studies methods and applications in which two or more consecutive images from an image sequences, e.g., produced by a video camera or high-speed camera, are processed to produce information based on the apparent motion in the images. In some applications, the camera is fixed relative to the scene and objects are moving around in the scene, in some applications the scene is more or less fixed and the camera is moving, and in some cases both the camera and the scene are moving. The motion analysis processing can in the simplest case be to detect motion, i.e., find the points in the image where something is moving. More complex types of processing can be to track a specific object in the image over time, to group points that belong to the same rigid object that is moving in the scene, or to determine the magnitude and direction of the motion of every point in the image. The information that is produced is often related to a specific image in the sequence, corresponding to a specific time-point, but then depends also on the neighboring images. This


id: motion-analysis-20260505-1
file: data/en.wikipedia.org/wiki/Motion_analysis-1.md
category: reference
title: Motion analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Motion_analysis
date_saved: 2026-05-05T10:02:38.023893+00:00
instance: kb-cron
parent: motion-analysis-20260505-0
summary:
=== Human motion analysis === In the areas of medicine, sports, video surveillance, physical therapy, and kinesiology, human motion analysis has become an investigative and diagnostic tool. See the section on motion capture for more detail on the technologies. Human motion analysis can be divided into three categories: human activity recognition, human motion tracking, and analysis of body and body part movement. Human activity recognition is most commonly used for video surveillance, specifically automatic motion monitoring for security purposes. Most efforts in this area rely on state-space approaches, in which sequences of static postures are statistically analyzed and compared to modeled movements. Template-matching is an alternative method whereby static shape patterns are compared to pre-existing prototypes. Human motion tracking can be performed in two or three dimensions. Depending on the complexity of analysis, representations of the human body range from basic stick figures to volumetric models. Tracking relies on the correspondence of image features between consecutive frames of video, taking into consideration information such as position, color, shape, and texture. Edge detection can be performed by comparing the color and/or contrast of adjacent pixels, looking specifically for discontinuities or rapid changes. Three-dimensional tracking is fundamentally identical to two-dimensional tracking, with


id: multimethodology-20260505-0
file: data/en.wikipedia.org/wiki/Multimethodology-0.md
category: reference
title: Multimethodology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Multimethodology
date_saved: 2026-05-05T10:02:39.234877+00:00
instance: kb-cron
parent: multimethodology-20260505-0
summary:
Multimethodology or multimethod research includes the use of more than one method of data collection or research in a research study or set of related studies. Mixed methods research is more specific in that it includes the mixing of qualitative and quantitative data, methods, methodologies, and/or paradigms in a research study or set of related studies. One could argue that mixed methods research is a special case of multimethod research. Another applicable, but less often used label, for multi or mixed research is methodological pluralism. All of these approaches to professional and academic research emphasize that monomethod research can be improved through the use of multiple data sources, methods, research methodologies, perspectives, standpoints, and paradigms. The term multimethodology was used starting in the 1980s and in the 1989 book Multimethod Research: A Synthesis of Styles by John Brewer and Albert Hunter. During the 1990s and currently, the term mixed methods research has become more popular for this research movement in the behavioral, social, business, and health sciences. This pluralistic research approach has been gaining in popularity since the 1980s. == Multi and mixed methods research designs == There are four broad classes of research studies that are currently being labeled


id: multimethodology-20260505-1
file: data/en.wikipedia.org/wiki/Multimethodology-1.md
category: reference
title: Multimethodology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Multimethodology
date_saved: 2026-05-05T10:02:39.234877+00:00
instance: kb-cron
parent: multimethodology-20260505-0
summary:
=== History of Pragmatism in Multi/Mixed Methods Research === Developed as a philosophical method to solve problems towards the end of the nineteenth century, pragmatism is attributed to the work of philosopher Charles Sanders Peirce. For Peirce, research is conducted and interpreted from the eye of the beholder, as a practical approach to investigating social affairs. He sees science as a communal affair leading to single truths that are arrived at from multiple perspectives. For Peirce, the research conclusions are not as important as how these conclusions are reached. Focus is on answering the research question while allowing the methods to emerge in the process. Peirce pragmatism and its approach to research support qualitatively driven mixed methods studies. John Dewey extends both, "Peirce pragmatic method and (William) James' radical empiricism (and approach to experience) by application to social and political problems." His philosophical pragmatism takes an interdisciplinary approach, where the divide between quantitative and qualitative research represents an obstacle to solving a problem. In Dewey's pragmatism, success is measured by the outcome, where the outcome is the reason to engage in research. Live experiences constitute reality, were individual lived experiences form a continuum by the interaction of subjective (internal) and


id: multimethodology-20260505-2
file: data/en.wikipedia.org/wiki/Multimethodology-2.md
category: reference
title: Multimethodology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Multimethodology
date_saved: 2026-05-05T10:02:39.234877+00:00
instance: kb-cron
parent: multimethodology-20260505-0
summary:
== In contrast to quantitative and qualitative methodologies == One major similarity between mixed methodologies and qualitative and quantitative taken separately is that researchers need to maintain focus on the original purpose behind their methodological choices. A major difference between the two, however, is the way some authors differentiate the two, proposing that there is logic inherent in one that is different from the other. Creswell (2009) points out that in a quantitative study the researcher starts with a problem statement, moving on to the hypothesis and null hypothesis, through the instrumentation into a discussion of data collection, population, and data analysis. Creswell proposes that for a qualitative study the flow of logic begins with the purpose for the study, moves through the research questions discussed as data collected from a smaller group and then voices how they will be analysed. A research strategy is a procedure for achieving a particular intermediary research objective — such as sampling, data collection, or data analysis. We may therefore speak of sampling strategies or data analysis strategies. The use of multiple strategies to enhance construct validity (a form of methodological triangulation) is now routinely advocated by methodologists. In short, mixing or integrating research


id: multimodal-anthropology-20260505-0
file: data/en.wikipedia.org/wiki/Multimodal_anthropology-0.md
category: reference
title: Multimodal anthropology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Multimodal_anthropology
date_saved: 2026-05-05T10:02:40.406904+00:00
instance: kb-cron
parent: multimodal-anthropology-20260505-0
summary:
Multimodal anthropology is an emerging subfield of social cultural anthropology that encompasses anthropological research and knowledge production across multiple traditional and new media platforms and practices including film, video, photography, theatre, design, podcast, mobile apps, interactive games, web-based social networking, immersive 360 video and augmented reality. As characterized in American Anthropologist, multimodal anthropology is an "anthropology that works across multiple media, but one that also engages in public anthropology and collaborative anthropology through a field of differentially linked media platforms" (Collins, Durington & Gill). A multimodal approach also encourages anthropologists to reconsider the ways in which they conduct their research, to pay close attention to the role various media technologies and digital devices plays in the lives of their interlocutors, and how they these technologies redefine what fieldwork looks like. Scholars Collins, Durington, and Gill call it "anthropology that works across multiple media." It's not just about doing research alone; it's also about working with others and looking at how we do research in new ways, as well as an 'embodied practice', according to Varvantakis and Nolas. Multimodal anthropology has been growing since the early days of anthropology, changing along with new technology. It's not just about pictures anymore; now


id: multiplex-assay-20260505-0
file: data/en.wikipedia.org/wiki/Multiplex_(assay)-0.md
category: reference
title: Multiplex (assay)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Multiplex_(assay)
date_saved: 2026-05-05T10:02:41.610505+00:00
instance: kb-cron
parent: multiplex-assay-20260505-0
summary:
In the biological sciences, a multiplex assay is a type of immunoassay that uses magnetic beads to simultaneously measure multiple analytes in a single experiment. A multiplex assay is a derivative of an ELISA using beads for binding the capture antibody. Multiplex assays are still more common in research than in clinical settings. In a multiplex assay, microspheres of designated colors are coated with antibodies of defined binding specificities. The results can be read by flow cytometry because the beads are distinguishable by fluorescent signature. The number of analytes measured is determined by the number of different bead colors. Multiplex assays within a given application area or class of technology can be further stratified based on how many analytes can be measured per assay, where "multiplex" refers to those with the highest number of analyte measurements per assay (up to millions) and "low-plex" or "mid-plex" refers to procedures that process fewer (10s to 1000s), though there are no formal guidelines for calling a procedure multi-, mid-, or low-plex based on number of analytes measured. Single-analyte assays or low-to-mid-plex procedures typically predate the rise of their multiplex versions, which often require specialized technologies or miniaturization to achieve a higher degree of


id: network-based-diffusion-analysis-20260505-0
file: data/en.wikipedia.org/wiki/Network-based_diffusion_analysis-0.md
category: reference
title: Network-based diffusion analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Network-based_diffusion_analysis
date_saved: 2026-05-05T10:02:42.840541+00:00
instance: kb-cron
parent: network-based-diffusion-analysis-20260505-0
summary:
Network-based diffusion analysis (NBDA) is a statistical tool to detect and quantify social transmission of information or a behaviour in social networks (SNA, etc.). NBDA assumes that social transmission of a behavior follows the social network of associations or interactions among individuals, since individuals who spend a lot of time together, or who interact more have more opportunity to learn from each other. Therefore, NBDA infers social transmission if the spread of a novel behavior follows the social network of a population. NBDA thus allows the study of social learning to be linked to animal behavior research that uses social network analysis. NBDA was introduced by Franz & Nunn and further developed by Hoppitt, Boogert, & Laland. An R package for performing Bayesian NBDA, STbayes, was published by Chimento & Hoppitt in 2025. == Implementation == NBDA requires prior knowledge about the underlying social network of a population. In an observational study, the order (or timing) at which individuals in the population acquire a behaviour or information is recorded. NBDA then tests whether the spread of information or behaviour is explained by the previously determined network or not. Because more closely associated individuals are more likely to interact with each


id: open-label-trial-20260505-0
file: data/en.wikipedia.org/wiki/Open-label_trial-0.md
category: reference
title: Open-label trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Open-label_trial
date_saved: 2026-05-05T10:02:44.071326+00:00
instance: kb-cron
parent: open-label-trial-20260505-0
summary:
An open-label trial, or open trial, is a type of clinical trial in which information is not withheld from trial participants. In particular, both the researchers and participants know which treatment is being administered. This contrasts with a double-blinded trial, where information is withheld both from the researchers and the participants to reduce bias. Open-label trials may be appropriate for comparing two similar treatments to determine which is most effective, such as a comparison of different prescription anticoagulants, or possible relief from symptoms of some disorders when a placebo is given. An open-label trial may still be randomized. Open-label trials may also be uncontrolled (without a placebo group), with all participants receiving the same treatment. This would be a single-arm study design. == References ==


id: parallel-study-20260505-0
file: data/en.wikipedia.org/wiki/Parallel_study-0.md
category: reference
title: Parallel study
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Parallel_study
date_saved: 2026-05-05T10:02:45.211284+00:00
instance: kb-cron
parent: parallel-study-20260505-0
summary:
A parallel study is a type of clinical study where two groups of treatments, A and B, are given so that one group receives only A while another group receives only B. Other names for this type of study include "between patient" and "non-crossover". This is unlike a crossover study where at first one group receives treatment A and later followed by treatment B while the other group receives treatment B followed by treatment A. There are, however, certain characteristics that allow for differentiation between these two types of trials. For example, a parallel study would be more appropriate if any concerns about carryover effects were present. This type of study might also be more beneficial if the disease or disorder being studied has a likely chance of progression during the time in which the study takes place. One significant issue with parallel studies, though, is the concept of intra subject variability, which is defined as variability in response occurring within the same patient. The two treatment groups in a parallel study can either consist of two completely separate treatments (i.e. different drugs), or simply different doses of a common drug. One major aspect of a parallel study is randomization


id: parataxonomy-20260505-0
file: data/en.wikipedia.org/wiki/Parataxonomy-0.md
category: reference
title: Parataxonomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Parataxonomy
date_saved: 2026-05-05T10:02:46.406435+00:00
instance: kb-cron
parent: parataxonomy-20260505-0
summary:
Parataxonomy is a system of labor division for use in biodiversity research, in which the rough sorting tasks of specimen collection, field identification, documentation and preservation are conducted by primarily local, less specialized individuals, thereby alleviating the workload for the "alpha" or "master" taxonomist. Parataxonomy may be used to improve taxonomic efficiency by enabling more expert taxonomists to restrict their activity to the tasks that require their specialist knowledge and skills, which has the potential to expedite the rate at which new taxa may be described and existing taxa may be sorted and discussed. Parataxonomists generally work in the field, sorting collected samples into recognizable taxonomic units (RTUs) based on easily recognized features. The process can be used alone for rapid assessment of biodiversity. Some researchers consider reliance on parataxonomist-generated data to be prone to error depending on the sample, the sorter and the group of organisms in question. Therefore, quantitative studies based on parataxonomic processes may be unreliable and is therefore controversial. The concepts of citizen science and parataxonomy are somewhat overlapping, with unclear distinctions between those employed to provide supplemental services to taxonomists and those who do so voluntarily, whether for personal enrichment or the altruistic desire to


id: participatory-action-research-20260505-0
file: data/en.wikipedia.org/wiki/Participatory_action_research-0.md
category: reference
title: Participatory action research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_action_research
date_saved: 2026-05-05T10:02:47.553680+00:00
instance: kb-cron
parent: participatory-action-research-20260505-0
summary:
Participatory action research (PAR) is an approach to action research emphasizing participation and action by members of communities affected by that research. It seeks to understand the world by trying to change it, collaboratively and following reflection. PAR emphasizes collective inquiry and experimentation grounded in experience and social history. Within a PAR process, "communities of inquiry and action evolve and address questions and issues that are significant for those who participate as co-researchers". PAR contrasts with mainstream research methods, which emphasize controlled experimentaction, statistical analysis, and reproducibility of findings. PAR practitioners make a concerted effort to integrate three basic aspects of their work: participation (life in society and democracy), action (engagement with experience and history), and research (soundness in thought and the growth of knowledge). "Action unites, organically, with research" and collective processes of self-investigation. The way each component is actually understood and the relative emphasis it receives varies nonetheless from one PAR theory and practice to another. This means that PAR is not a monolithic body of ideas and methods but rather a pluralistic orientation to knowledge making and social change. == Overview == In the UK and North America the work of Kurt Lewin and the Tavistock Institute


id: participatory-action-research-20260505-1
file: data/en.wikipedia.org/wiki/Participatory_action_research-1.md
category: reference
title: Participatory action research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_action_research
date_saved: 2026-05-05T10:02:47.553680+00:00
instance: kb-cron
parent: participatory-action-research-20260505-0
summary:
"Do not monopolise your knowledge nor impose arrogantly your techniques, but respect and combine your skills with the knowledge of the researched or grassroots communities, taking them as full partners and co-researchers. Do not trust elitist versions of history and science which respond to dominant interests, but be receptive to counter-narratives and try to recapture them. Do not depend solely on your culture to interpret facts, but recover local values, traits, beliefs, and arts for action by and with the research organisations. Do not impose your own ponderous scientific style for communicating results, but diffuse and share what you have learned together with the people, in a manner that is wholly understandable and even literary and pleasant, for science should not be necessarily a mystery nor a monopoly of experts and intellectuals." PAR can be thought of as a guiding paradigm to influence and democratize the creation of knowledge making, and ground it in real community needs and learning. Knowledge production controlled by elites can sometimes further oppress marginalized populations. PAR can be a way of overcoming the ineffectiveness and elitism of conventional schooling and science, and the negative effects of market forces and industry on the workplace, community life


id: participatory-action-research-20260505-2
file: data/en.wikipedia.org/wiki/Participatory_action_research-2.md
category: reference
title: Participatory action research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_action_research
date_saved: 2026-05-05T10:02:47.553680+00:00
instance: kb-cron
parent: participatory-action-research-20260505-0
summary:
=== Organizational life === Action research in the workplace took its initial inspiration from Lewin's work on organizational development (and Dewey's emphasis on learning from experience). Lewin's seminal contribution involves a flexible, scientific approach to planned change that proceeds through a spiral of steps, each of which is composed of 'a circle of planning, action, and fact-finding about the result of the action', towards an organizational 'climate' of democratic leadership and responsible participation that promotes critical self-inquiry and collaborative work. These steps inform Lewin's work with basic skill training groups, T-groups where community leaders and group facilitators use feedback, problem solving, role play and cognitive aids (lectures, handouts, film) to gain insights into themselves, others and groups with a view to 'unfreezing' and changing their mindsets, attitudes and behaviours. Lewin's understanding of action-research coincides with key ideas and practices developed at the influential Tavistock Institute (created in 1947)) in the UK and National Training Laboratories (NTL) in the US. An important offshoot of Tavistock thinking and practise is the sociotechnical systems perspective on workplace dynamics, guided by the idea that greater productivity or efficiency does not hinge on improved technology alone. Improvements in organizational life call instead for the interaction


id: participatory-action-research-20260505-3
file: data/en.wikipedia.org/wiki/Participatory_action_research-3.md
category: reference
title: Participatory action research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_action_research
date_saved: 2026-05-05T10:02:47.553680+00:00
instance: kb-cron
parent: participatory-action-research-20260505-0
summary:
=== Community development and sustainable livelihoods === PAR emerged in the postwar years as an important contribution to intervention and self-transformation within groups, organizations and communities. It has left a singular mark on the field of rural and community development, especially in the Global South. Tools and concepts for doing research with people, including "barefoot scientists" and grassroots "organic intellectuals" (see Gramsci), are now promoted and implemented by many international development agencies, researchers, consultants, civil society and local community organizations around the world. This has resulted in countless experiments in diagnostic assessment, scenario planning and project evaluation in areas ranging from fisheries and mining to forestry, plant breeding, agriculture, farming systems research and extension, watershed management, resource mapping, environmental conflict and natural resource management, land rights, appropriate technology, local economic development, communication, tourism, leadership for sustainability, biodiversity and climate change. This prolific literature includes the many insights and methodological creativity of participatory monitoring, participatory rural appraisal (PRA) and participatory learning and action (PLA) and all action-oriented studies of local, indigenous or traditional knowledge. On the whole, PAR applications in these fields are committed to problem solving and adaptation to nature at the household or community level, using friendly methods of


id: participatory-action-research-20260505-4
file: data/en.wikipedia.org/wiki/Participatory_action_research-4.md
category: reference
title: Participatory action research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_action_research
date_saved: 2026-05-05T10:02:47.553680+00:00
instance: kb-cron
parent: participatory-action-research-20260505-0
summary:
=== Feminism and gender === Feminist research and women's development theory also contributed to rethinking the role of scholarship in challenging existing regimes of power, using qualitative and interpretive methods that emphasize subjectivity and self-inquiry rather than the quantitative approach of mainstream science. As did most research in the 1970s and 1980s, PAR remained androcentric. In 1987, Patricia Maguire critiqued this male-centered participatory research, arguing that "rarely have feminist and participatory action researchers acknowledged each other with mutually important contributions to the journey." Given that PAR aims to give equitable opportunity for diverse and marginalized voices to be heard, engaging gender minorities is an integral pillar in PAR's tenants. In addition to gender minorities, PAR must consider points of intersecting oppressions individuals may experience. After Maguire published Traveling Companions: Feminism, Teaching, And Action Research, PAR began to extend toward not only feminism, but also Intersectionality through Black Feminist Thought and Critical Race Theory (CRT). Today, applying an intersectional feminist lens to PAR is crucial to recognize the social categories, such as race, class, ability, gender, and sexuality, that construct individuals' power relations and lived experiences. PAR seeks to recognize the deeply complex condition of human living. Therefore, framing PAR's qualitative


id: participatory-action-research-20260505-5
file: data/en.wikipedia.org/wiki/Participatory_action_research-5.md
category: reference
title: Participatory action research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_action_research
date_saved: 2026-05-05T10:02:47.553680+00:00
instance: kb-cron
parent: participatory-action-research-20260505-0
summary:
== Ethics == Given the often delicate power balances between researchers and participants in PAR, there have been calls for a code of ethics to guide the relationship between researchers and participants in a variety of PAR fields. Norms in research ethics involving humans include respect for the autonomy of individuals and groups to deliberate about a decision and act on it. This principle is usually expressed through the free, informed and ongoing consent of those participating in research (or those representing them in the case of persons lacking the capacity to decide). Another mainstream principle is the welfare of participants who should not be exposed to any unfavourable balance of benefits and risks with participation in research aimed at the advancement of knowledge, especially those that are serious and probable. Since privacy is a factor that contributes to people's welfare, confidentiality obtained through the collection and use of data that are anonymous (e.g. survey data) or anonymized tends to be the norm. Finally, the principle of justice—equal treatment and concern for fairness and equity—calls for measures of appropriate inclusion and mechanisms to address conflicts of interests. While the choice of appropriate norms of ethical conduct is rarely an either/or


id: participatory-action-research-20260505-6
file: data/en.wikipedia.org/wiki/Participatory_action_research-6.md
category: reference
title: Participatory action research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_action_research
date_saved: 2026-05-05T10:02:47.553680+00:00
instance: kb-cron
parent: participatory-action-research-20260505-0
summary:
== Challenges == PAR offers a long history of experimentation with evidence-based and people-based inquiry, a groundbreaking alternative to mainstream positive science. As with positivism, the approach creates many challenges as well as debates on what counts as participation, action and research. Differences in theoretical commitments (Lewinian, Habermasian, Freirean, psychoanalytic, feminist, etc.) and methodological inclinations (quantitative, qualitative, mixed) are numerous and profound. This is not necessarily a problem, given the pluralistic value system built into PAR. Ways to better answer questions pertaining to PAR's relationship with science and social history are nonetheless key to its future. One critical question concerns the problem-solving orientation of engaged inquiry—the rational means-ends focus of most PAR experiments as they affect organizational performance or material livelihoods, for instance. In the clinical perspective of French psychosociology, a pragmatic orientation to inquiry neglects forms of understanding and consciousness that are not strictly instrumental and rational. PAR must pay equal attention to the interconnections of self-awareness, the unconscious and life in society. Another issue, more widely debated, is scale—how to address broad-based systems of power and issues of complexity, especially those of another development on a global scale. How can PAR develop a macro-orientation to democratic dialogue and


id: participatory-design-20260505-0
file: data/en.wikipedia.org/wiki/Participatory_design-0.md
category: reference
title: Participatory design
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_design
date_saved: 2026-05-05T10:02:48.714500+00:00
instance: kb-cron
parent: participatory-design-20260505-0
summary:
Participatory design (originally co-operative design or design participation, now often co-design and also co-creation) is an approach to design that attempts to involve a variety of stakeholders (e.g. employees, partners, customers, citizens, end users) in the design process to help ensure the result meets their needs and is usable. Participatory design is an approach which is focused on processes and procedures of design and is not a design style. The term is used in a variety of fields, e.g. software design, urban design, architecture, landscape architecture, product design, sustainability, graphic design, industrial design, planning, and health services development, as a way of creating environments that are more satisfactory and appropriate to their inhabitants' and users' practical, cultural, emotional and spiritual needs. It is also one approach to placemaking. Participatory design has been used in many settings and at various scales. For some, this approach has a political dimension of user empowerment and democratization. This inclusion of external parties in the design process does not excuse designers of their responsibilities. In their article "Participatory Design and Prototyping", Wendy Mackay and Michel Beaudouin-Lafon support this point by stating that "[a] common misconception about participatory design is that designers are expected to abdicate


id: participatory-design-20260505-1
file: data/en.wikipedia.org/wiki/Participatory_design-1.md
category: reference
title: Participatory design
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_design
date_saved: 2026-05-05T10:02:48.714500+00:00
instance: kb-cron
parent: participatory-design-20260505-0
summary:
=== History in Scandinavia === In several Scandinavian countries, during the 1960s and 1970s, participatory design was rooted in work with trade unions; its ancestry also includes action research and sociotechnical design. Research projects on user participation in systems development date back to the 1970s. The so-called "collective resource approach" developed strategies and techniques for workers to influence the design and use of computer applications at the workplace: The Norwegian Iron and Metal Workers Union (NJMF) project took a first move from traditional research to working with people, directly changing the role of the union clubs in the project. The Scandinavian projects developed an action research approach, emphasizing active co-operation between researchers and workers of the organization to help improve the latter's work situation. While researchers got their results, the people whom they worked with were equally entitled to get something out of the project. The approach built on people's own experiences, providing for them resources to be able to act in their current situation. The view of organizations as fundamentally harmonious—according to which conflicts in an organization are regarded as pseudo-conflicts or "problems" dissolved by good analysis and increased communication—was rejected in favor of a view of organizations recognizing


id: participatory-design-20260505-2
file: data/en.wikipedia.org/wiki/Participatory_design-2.md
category: reference
title: Participatory design
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_design
date_saved: 2026-05-05T10:02:48.714500+00:00
instance: kb-cron
parent: participatory-design-20260505-0
summary:
Public interest design is a design movement, extending to architecture, with the main aim of structuring design around the needs of the community. At the core of its application is participatory design. Through allowing individuals to have a say in the process of design of their own surrounding built environment, design can become proactive and tailored towards addressing wider social issues facing that community. Public interest design is meant to reshape conventional modern architectural practice. Instead of having each construction project solely meet the needs of the individual, public interest design addresses wider social issues at their core. This shift in architectural practice is a structural and systemic one, allowing design to serve communities responsibly. Solutions to social issues can be addressed in a long-term manner through such design, serving the public, and involving it directly in the process through participatory design. The built environment can become the very reason for social and community issues to arise if not executed properly and responsibly. Conventional architectural practice often does cause such problems since only the paying client has a say in the design process. Portland, Oregon City Repair Project was a form of participatory design involving the community co-designing problem areas


id: participatory-design-20260505-3
file: data/en.wikipedia.org/wiki/Participatory_design-3.md
category: reference
title: Participatory design
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Participatory_design
date_saved: 2026-05-05T10:02:48.714500+00:00
instance: kb-cron
parent: participatory-design-20260505-0
summary:
== Research methodology == Increasingly researchers are focusing on co-design as a way of doing research, and therefore are developing parts of its research methodology. For instance, in the field of generative co-design Vandekerckhove et al. have proposed a methodology to assemble a group of stakeholders to participate in generative co-design activities in the early innovation process. They propose first to sample a group of potential stakeholders through snowball sampling, afterwards interview these people and assess their knowledge and inference experience, lastly they propose to assemble a diverse group of stakeholders according to their knowledge and inference experience. Though not completely synonymous, research methods of Participatory Design can be defined under Participatory Research (PR): a term for research designs and frameworks using direct collaboration with those affected by the studied issue. More specifically, Participatory Design has evolved from Community-Based Research and Participatory Action Research (PAR). PAR is a qualitative research methodology involving: "three types of change, including critical consciousness development of researchers and participants, improvement of lives of those participating in research, and transformation of societal 'decolonizing' research methods with the power of healing and social justice". Participatory Action Research (PAR) is a subset of Community-Based Research aimed explicitly at


id: patient-and-public-involvement-20260505-0
file: data/en.wikipedia.org/wiki/Patient_and_public_involvement-0.md
category: reference
title: Patient and public involvement
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Patient_and_public_involvement
date_saved: 2026-05-05T10:02:49.972651+00:00
instance: kb-cron
parent: patient-and-public-involvement-20260505-0
summary:
Public involvement (or public and patient involvement, PPI) in medical research refers to the practice where people with health conditions (patients), carers and members of the public work together with researchers and influence what is researched and how. Involvement is not the same as participation which means taking part in research, for example taking a drug in a clinical trial. == Definition == Public involvement in medical research can be defined as research being carried out "with" or "by" members of the public rather than "to", "about" or "for" them. Through PPI patients, carers and people with lived experience work alongside researchers to influence and contribute to how research is designed and conducted. Members of the public involved in research are frequently referred to as public members or public contributors. === Terminology === Researchers and others use different terms to describe how they interact with the public, and this can vary across organisations and countries. The terms involvement, engagement and participation are sometimes used interchangeably. The National Institute for Health and Care Research (NIHR) uses the term public partnerships to encompass the components of involvement, engagement and participation. It can be summarised as "a term to collectively describe ways in


id: patient-and-public-involvement-20260505-1
file: data/en.wikipedia.org/wiki/Patient_and_public_involvement-1.md
category: reference
title: Patient and public involvement
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Patient_and_public_involvement
date_saved: 2026-05-05T10:02:49.972651+00:00
instance: kb-cron
parent: patient-and-public-involvement-20260505-0
summary:
Identifying and prioritising research. People with lived experience help to identify the right topics to ensure that the research is looking at what matters to them. Commissioning research. Involving members of the public in deciding which research proposals should get funding. Public members can also continue monitoring the research projects that get funded. Designing research. Public members help designing the research to make sure it is feasible, ethical and relevant. This happens usually before applying for funding. Managing research. Public involvement in the steering group or managing committee that oversees the research. Undertaking research. Members of the public help carrying out the research. This can include, for example, gathering evidence, reviewing literature, conducting interviews and focus groups, and analysing the results. Disseminating (sharing) research. Public members help sharing the findings of research. They can be consulted on the ways of dissemination, help summarising the research in plain language, work on accessibility issues. Implementing research. Public members influencing how the result is taken into practice and making sure it leads to action. Public involvement can be short-term and task-based or long-term across a research project or an institutional programme. == Barriers and issues == There are a wide range of challenges


id: patient-and-public-involvement-20260505-2
file: data/en.wikipedia.org/wiki/Patient_and_public_involvement-2.md
category: reference
title: Patient and public involvement
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Patient_and_public_involvement
date_saved: 2026-05-05T10:02:49.972651+00:00
instance: kb-cron
parent: patient-and-public-involvement-20260505-0
summary:
== Diversity and inclusion == In order for research to be relevant for all, the PPI process needs to include members of the public from diverse and inclusive groups. A 2021 survey highlights that the majority of public contributors to NIHR research were predominantly female (57%), 61 years of age and over, white and heterosexual. The Health Research Authority found that people from ethnic and lower socioeconomic groups felt less confident about being treated in a dignified and respectful way in research in comparison to white and higher socioeconomic individuals. Black and minority ethnic (BME) involvement in research has widespread support, however it tends to be limited to certain phases of the research cycle and particular ethnicities. === Frameworks for diversity === The Race Equality Framework (REF) was produced as a self assessment tool aiming to help organisations improve racial equity in health and care research. It was co-produced by the Race Equality Public Action Group (REPAG). Similar frameworks exist for research participants, for example, the INCLUDE ethnicity framework and the National Health Service (NHS) guidance for increasing diversity in research participation. == History == The development of patient and public involvement in research was influenced by grassroots social movements,


id: periscop-20260505-0
file: data/en.wikipedia.org/wiki/PERISCOP-0.md
category: reference
title: PERISCOP
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/PERISCOP
date_saved: 2026-05-05T10:02:51.163872+00:00
instance: kb-cron
parent: periscop-20260505-0
summary:
The PERISCOP is a pressurized recovery device designed for retrieving deep-sea marine life at depths exceeding 2,000 metres. The device was designed by Bruce Shillito and Gerard Hamel at the Universite Pierre et Marie Curie. The name is an acronym for the French phrase Projet d’Enceinte de Remontée Isobare Servant la Capture d’Organismes Profonds ("Enclosure project for isobaric ascent serving to capture deep organisms"). == History == The PERISCOP is a unique pressurized recovery device that contains three chambers – one for capture, one for recovery under exterior pressure, and one for transfer to the laboratory while maintaining pressure. Previous recovery devices used one chamber for all purposes. An arm designed to capture samples by force of suction is attached to the device. During ascent, pressure is maintained within the chamber by use of pressurized water. Upon surfacing, samples can be observed, filmed, and/or photographed through transparent view ports in the device. Due to fluctuations in atmospheric pressure and temperature recorded pressures during ascent and at the surface may ranged from 74%-111% of the natural pressure at sea depth. The device set a record for the deepest live-fish capture under pressure when it captured a Pachycara at 2,300 m. The


id: pooled-analysis-20260505-0
file: data/en.wikipedia.org/wiki/Pooled_analysis-0.md
category: reference
title: Pooled analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pooled_analysis
date_saved: 2026-05-05T10:02:52.330665+00:00
instance: kb-cron
parent: pooled-analysis-20260505-0
summary:
A pooled analysis is a statistical technique for combining the results of multiple epidemiological studies. It is one of three types of literature reviews frequently used in epidemiology, along with meta-analysis and traditional narrative reviews. Pooled analyses may be either retrospective or prospective. It is often used when the results of individual studies do not allow for a firm conclusion to be drawn. Unlike meta-analyses, pooled analyses can only be conducted if the included studies used the same study design and statistical models, and if their respective populations were homogeneous. If individual-level data from the included studies is available, the result of a pooled analysis can be considered more reliable. == References ==


id: postmortem-studies-20260505-0
file: data/en.wikipedia.org/wiki/Postmortem_studies-0.md
category: reference
title: Postmortem studies
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Postmortem_studies
date_saved: 2026-05-05T10:02:53.502702+00:00
instance: kb-cron
parent: postmortem-studies-20260505-0
summary:
Postmortem studies are a type of neurobiological research, which provides information to researchers and individuals who will have to make medical decisions in the future. Postmortem researchers conduct a longitudinal study of the brain of an individual, who has some sort of phenomenological condition (i.e. cannot speak, trouble moving left side of body, Alzheimer's, etc.) that is examined after death. Researchers look at certain lesions in the brain that could have an influence on cognitive or motor functions. These irregularities, damage, or other cerebral anomalies observed in the brain are attributed to an individual's pathophysiology and their environmental surroundings. Postmortem studies provide a unique opportunity for researchers to study different brain attributes that would be unable to be studied on a living person. Postmortem studies allow researchers to determine causes and cure for certain diseases and functions. It is critical for researchers to develop hypotheses, in order to discover the characteristics that are meaningful to a particular disorder. The results that the researcher discovers from the study will help the researcher trace the location in the brain to specific behaviors. When tissue from a postmortem study is obtained it is imperative that the researcher ensures the quality is adequate to


id: pragmatic-validity-20260505-0
file: data/en.wikipedia.org/wiki/Pragmatic_validity-0.md
category: reference
title: Pragmatic validity
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pragmatic_validity
date_saved: 2026-05-05T10:02:54.708020+00:00
instance: kb-cron
parent: pragmatic-validity-20260505-0
summary:
Pragmatic validity in research looks to a different paradigms from more traditional, (post)positivistic research approaches. It tries to ameliorate problems associated with the rigour-relevance debate, and is applicable in all kinds of research streams. Simply put, pragmatic validity looks at research from a prescriptive-driven perspective. Solutions to problems that actually occur in the complex and highly multivariate field of practice are developed in a way that, while valid for a specific situation, need to be adjusted according to the context in which they are to be applied. The term "validity" is often seen as a sort catch-all for the question whether the knowledge claims resulting from research are warranted. The confusion might arise from the mingling of the terms 'internal validity' and 'external validity', where the former refers to proof of a causal link between a treatment and effect, and the latter is concerned with generalizability. (In this discussion I maintain the term 'generalizability' rather than external validity mainly to avoid any possible confusion between the two terms.) During this discussion I consider that validity is reflected in the question, "did we measure the right thing?", or, in other words, can the researcher prove that the effect he observed was


id: pragmatic-validity-20260505-1
file: data/en.wikipedia.org/wiki/Pragmatic_validity-1.md
category: reference
title: Pragmatic validity
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pragmatic_validity
date_saved: 2026-05-05T10:02:54.708020+00:00
instance: kb-cron
parent: pragmatic-validity-20260505-0
summary:
Thus, Cook (1983) actually questions the validity of causal explanations generated in a context-free setting (the goal of positivistic, explanatory research). Causal relationships in pragmatic research are looked at somewhat differently, which is apparent in the wording alone. A statement about a causal relationship in positivistic research is something like the following; if you perform action x to subject y, then z happens. This assumes that the confounding variables have been ruled out, and the statement is always true, regardless of the situation (internally and externally valid). What I want to do now is use the concept of 'technological rules' in order to illustrate how causality is shown in prescriptive. In pragmatic science, the goal is to develop knowledge that can be used to improve a situation. This we can call prescriptive knowledge. Prescriptive knowledge, according to van Aken (2004, 2004b, 2005) can take the form of a technological rule. A technological rule is "... a chunk of general knowledge linking an intervention or artifact with an expected outcome or performance in a certain field of application" (van Aken, 2005: p23). This rule can be formulated much the same way as my earlier example of a causal statement; 'if you


id: qualitative-research-20260505-0
file: data/en.wikipedia.org/wiki/Qualitative_research-0.md
category: reference
title: Qualitative research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualitative_research
date_saved: 2026-05-05T10:02:55.894451+00:00
instance: kb-cron
parent: qualitative-research-20260505-0
summary:
Qualitative research is a type of research that aims to gather and analyse non-numerical (descriptive) data in order to gain an understanding of individuals' social reality, including understanding their attitudes, beliefs, and motivation. This type of research typically involves in-depth interviews, focus groups, or field observations in order to collect data that is rich in detail and context. Qualitative research is often used to explore complex phenomena or to gain insight into people's experiences and perspectives on a particular topic. It is particularly useful when researchers want to understand the meaning that people attach to their experiences or when they want to uncover the underlying reasons for people's behavior. Qualitative methods include ethnography, grounded theory, discourse analysis, and interpretative phenomenological analysis. Qualitative research methods have been used in sociology, anthropology, political science, psychology, communication studies, social work, folklore, educational research, information science and software engineering research. == Background == Qualitative research has been informed by several strands of philosophical thought and examines aspects of human life, including culture, expression, beliefs, morality, life stress, and imagination. Contemporary qualitative research has been influenced by a number of branches of philosophy, for example, positivism, postpositivism, critical theory, and constructivism. The historical transitions or


id: qualitative-research-20260505-1
file: data/en.wikipedia.org/wiki/Qualitative_research-1.md
category: reference
title: Qualitative research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualitative_research
date_saved: 2026-05-05T10:02:55.894451+00:00
instance: kb-cron
parent: qualitative-research-20260505-0
summary:
== Data analysis == Qualitative researchers have a number of analytic strategies available to them. === Coding === In general, coding refers to the act of associating meaningful ideas with the data of interest. In the context of qualitative research, interpretative aspects of the coding process are often explicitly recognized and articulated; coding helps to produce specific words or short phrases believed to be useful abstractions from the data. === Pattern thematic analysis === Data may be sorted into patterns for thematic analyses as the primary basis for organizing and reporting the study findings. === Content analysis === According to Krippendorf, "Content analysis is a research technique for making replicable and valid inference from data to their context" (p. 21). It is applied to documents and written and oral communication. Content analysis is an important building block in the conceptual analysis of qualitative data. It is frequently used in sociology. For example, content analysis has been applied to research on such diverse aspects of human life as changes in perceptions of race over time, the lifestyles of contractors, and even reviews of automobiles. == Multi-method qualitative analysis == === Benefits === This is, for example, illustrated by studies on classroom


id: qualitative-research-20260505-2
file: data/en.wikipedia.org/wiki/Qualitative_research-2.md
category: reference
title: Qualitative research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualitative_research
date_saved: 2026-05-05T10:02:55.894451+00:00
instance: kb-cron
parent: qualitative-research-20260505-0
summary:
=== Limitations of qualitative research === Qualitative research is not without limitations. These limitations include participant reactivity, the potential for a qualitative investigator to over-identify with one or more study participants, "the impracticality of the Glaser-Strauss idea that hypotheses arise from data unsullied by prior expectations," the inadequacy of qualitative research for testing cause-effect hypotheses, and the Baconian character of qualitative research. Participant reactivity refers to the fact that people often behave differently when they know they are being observed. Over-identifying with participants refers to a sympathetic investigator studying a group of people and ascribing, more than is warranted, a virtue or some other characteristic to one or more participants. Compared to qualitative research, experimental research and certain types of nonexperimental research (e.g., prospective studies), although not perfect, are better means for drawing cause-effect conclusions. Glaser and Strauss, influential members of the qualitative research community, pioneered the idea that theoretically important categories and hypotheses can emerge "naturally" from the observations a qualitative researcher collects, provided that the researcher is not guided by preconceptions. The ethologist David Katz wrote "a hungry animal divides the environment into edible and inedible things....Generally speaking, objects change...according to the needs of the animal." Karl Popper


id: qualitative-research-20260505-3
file: data/en.wikipedia.org/wiki/Qualitative_research-3.md
category: reference
title: Qualitative research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualitative_research
date_saved: 2026-05-05T10:02:55.894451+00:00
instance: kb-cron
parent: qualitative-research-20260505-0
summary:
== Further reading == Adler, P. A. & Adler, P. (1987). : context and meaning in social inquiry / edited by Richard Jessor, Anne Colby, and Richard A. Shweder OCLC 46597302 Baškarada, S. (2014) "Qualitative Case Study Guidelines", in The Qualitative Report, 19(40): 1-25. Available from [1] Archived 2015-03-26 at the Wayback Machine Boas, Franz (1943). "Recent anthropology". Science. 98 (2546): 311–314, 334–337. Bibcode:1943Sci....98..334B. doi:10.1126/science.98.2546.334. PMID 17794461. Creswell, J. W. (2003). Research design: Qualitative, quantitative, and mixed method approaches. Thousand Oaks, CA: Sage Publications. Denzin, N. K., & Lincoln, Y. S. (2000). Handbook of qualitative research ( 2nd ed.). Thousand Oaks, CA: Sage Publications. Denzin, N. K., & Lincoln, Y. S. (2011). The SAGE Handbook of qualitative research ( 4th ed.). Los Angeles: Sage Publications. DeWalt, K. M. & DeWalt, B. R. (2002). Participant observation. Walnut Creek, CA: AltaMira Press. Fischer, C.T. (Ed.) (2005). Qualitative research methods for psychologists: Introduction through empirical studies. Academic Press. ISBN 0-12-088470-4. Franklin, M. I. (2012), "Understanding Research: Coping with the Quantitative-Qualitative Divide". London/New York. Routledge Giddens, A. (1990). The consequences of modernity. Stanford, CA: Stanford University Press. Gubrium, J. F. and J. A. Holstein. (2000). "The New Language of Qualitative Method." New York: Oxford


id: randomised-non-comparative-trial-20260505-0
file: data/en.wikipedia.org/wiki/Randomised_non-comparative_trial-0.md
category: reference
title: Randomised non-comparative trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Randomised_non-comparative_trial
date_saved: 2026-05-05T10:02:57.097615+00:00
instance: kb-cron
parent: randomised-non-comparative-trial-20260505-0
summary:
A randomised non-comparative trial, RNCT (or also non-comparative randomised trial), is a type of clinical trial where participants are randomised to different conditions (arms), but where the primary analysis involves comparing each arm separately to a historical control, predefined benchmark or something else, with no formal comparison between the two arms. The study design appears to have arisen in oncology, where single-arm studies are not unusual. It promises reduced sample size requirements. An RNCT acts like multiple single-arm designs run concurrently. A review found RNCTs dating back to 2002, and having been used in high-profile oncology studies and also beyond oncology. The design has been criticised by statisticians. It is unclear what benefit randomisation adds compared to running separate single-arm studies. Pavlos Msaouel described the use of the word "randomisation" as merely being "talismanic" in a 2025 article, it leading readers to think the study has the benefits of a randomised controlled trial (RCT). While the point of an RNCT is not to have a comparison between arms, about half of reported RNCTs still reported some sort of comparison. == References ==


id: randomized-controlled-trial-20260505-0
file: data/en.wikipedia.org/wiki/Randomized_controlled_trial-0.md
category: reference
title: Randomized controlled trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Randomized_controlled_trial
date_saved: 2026-05-05T10:02:58.342301+00:00
instance: kb-cron
parent: randomized-controlled-trial-20260505-0
summary:
A randomized controlled trial (RCT) is a type of statistical experiment designed to evaluate the efficacy or safety of an intervention by minimizing bias through the random allocation of participants to one or more comparison groups. In this approach, at least one group receives the intervention or process under study (such as a drug, surgical procedure, medical device or diet), while the other groups receive an alternative treatment, a placebo, or standard care. RCTs are a fundamental methodology in modern clinical trials and have been widely considered one of the highest-quality sources of evidence in evidence-based medicine, due to their ability to reduce selection bias and the influence of confounding factors. However, they have also been criticized for failing to reduce bias in some cases. Participants who enroll in RCTs differ from one another in known and unknown ways that can influence study outcomes, and yet cannot be directly controlled. By randomly allocating participants among compared treatments, an RCT enables statistical control over these influences. Provided it is designed well, conducted properly, and enrolls enough participants, an RCT may achieve sufficient control over these confounding factors to deliver a useful comparison of the treatments studied. == Definition and examples ==


id: randomized-controlled-trial-20260505-1
file: data/en.wikipedia.org/wiki/Randomized_controlled_trial-1.md
category: reference
title: Randomized controlled trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Randomized_controlled_trial
date_saved: 2026-05-05T10:02:58.342301+00:00
instance: kb-cron
parent: randomized-controlled-trial-20260505-0
summary:
== Ethics == Although subjects almost always provide informed consent for their participation in an RCT, studies since 1982 have documented that RCT subjects may believe that they are certain to receive treatment that is best for them personally; that is, they do not understand the difference between research and treatment. Determining the amount of information required to ensure informed consent can be difficult, and further research is necessary to determine the prevalence of and ways to address therapeutic misconception. Placebo-controlled trials have been deemed unethical in instances where not receiving treatment may lead to harm for the patient, such as an aggravation of symptoms or risk of death. Crossover trials, active-controlled trials, and other approaches have been used to mitigate this issue, though these options may not always be suitable for study, and have received their own criticism. Active-controlled trials in particular may raise ethical considerations regarding clinical equipoise. Although the principle of equipoise ("genuine uncertainty within the expert medical community... about the preferred treatment") is common to clinical trials and has been applied to RCTs, equipoise may be difficult to ascertain, and the ethics of RCTs have special considerations. It has been argued that equipoise itself is insufficient


id: randomized-controlled-trial-20260505-2
file: data/en.wikipedia.org/wiki/Randomized_controlled_trial-2.md
category: reference
title: Randomized controlled trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Randomized_controlled_trial
date_saved: 2026-05-05T10:02:58.342301+00:00
instance: kb-cron
parent: randomized-controlled-trial-20260505-0
summary:
"It eliminates bias in treatment assignment," specifically selection bias and confounding. "It facilitates blinding (masking) of the identity of treatments from investigators, participants, and assessors." "It permits the use of probability theory to express the likelihood that any difference in outcome between treatment groups merely indicates chance." There are two processes involved in randomizing patients to different interventions. First is choosing a randomization procedure to generate an unpredictable sequence of allocations; this may be a simple random assignment of patients to any of the groups at equal probabilities, may be "restricted", or may be "adaptive." A second and more practical issue is allocation concealment, which refers to the stringent precautions taken to ensure that the group assignment of patients are not revealed prior to definitively allocating them to their respective groups. Non-random "systematic" methods of group assignment, such as alternating subjects between one group and the other, can cause "limitless contamination possibilities" and can cause a breach of allocation concealment. However empirical evidence that adequate randomization changes outcomes relative to inadequate randomization has been difficult to detect. === Procedures === The treatment allocation is the desired proportion of patients in each treatment arm. An ideal randomization procedure would achieve the


id: randomized-controlled-trial-20260505-3
file: data/en.wikipedia.org/wiki/Randomized_controlled_trial-3.md
category: reference
title: Randomized controlled trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Randomized_controlled_trial
date_saved: 2026-05-05T10:02:58.342301+00:00
instance: kb-cron
parent: randomized-controlled-trial-20260505-0
summary:
"Allocation concealment" (defined as "the procedure for protecting the randomization process so that the treatment to be allocated is not known before the patient is entered into the study") is important in RCTs. In practice, clinical investigators in RCTs often find it difficult to maintain impartiality. Stories abound of investigators holding up sealed envelopes to lights or ransacking offices to determine group assignments in order to dictate the assignment of their next patient. Such practices introduce selection bias and confounders (both of which should be minimized by randomization), possibly distorting the results of the study. Adequate allocation concealment should defeat patients and investigators from discovering treatment allocation once a study is underway and after the study has concluded. Treatment related side-effects or adverse events may be specific enough to reveal allocation to investigators or patients thereby introducing bias or influencing any subjective parameters collected by investigators or requested from subjects. Some standard methods of ensuring allocation concealment include sequentially numbered, opaque, sealed envelopes (SNOSE); sequentially numbered containers; pharmacy controlled randomization; and central randomization. It is recommended that allocation concealment methods be included in an RCT's protocol, and that the allocation concealment methods should be reported in detail in a publication


id: randomized-controlled-trial-20260505-4
file: data/en.wikipedia.org/wiki/Randomized_controlled_trial-4.md
category: reference
title: Randomized controlled trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Randomized_controlled_trial
date_saved: 2026-05-05T10:02:58.342301+00:00
instance: kb-cron
parent: randomized-controlled-trial-20260505-0
summary:
=== Relative importance and observational studies === Two studies published in The New England Journal of Medicine in 2000 found that observational studies and RCTs overall produced similar results. The authors of the 2000 findings questioned the belief that "observational studies should not be used for defining evidence-based medical care" and that RCTs' results are "evidence of the highest grade." However, a 2001 study published in Journal of the American Medical Association concluded that "discrepancies beyond chance do occur and differences in estimated magnitude of treatment effect are very common" between observational studies and RCTs. According to a 2014 (updated in 2024) Cochrane review, there is little evidence for significant effect differences between observational studies and randomized controlled trials. To evaluate differences it is necessary to consider things other than design, such as heterogeneity, population, intervention or comparator. Two other lines of reasoning question RCTs' contribution to scientific knowledge beyond other types of studies: If study designs are ranked by their potential for new discoveries, then anecdotal evidence would be at the top of the list, followed by observational studies, followed by RCTs. RCTs may be unnecessary for treatments that have dramatic and rapid effects relative to the expected stable


id: randomized-controlled-trial-20260505-5
file: data/en.wikipedia.org/wiki/Randomized_controlled_trial-5.md
category: reference
title: Randomized controlled trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Randomized_controlled_trial
date_saved: 2026-05-05T10:02:58.342301+00:00
instance: kb-cron
parent: randomized-controlled-trial-20260505-0
summary:
=== Time and costs === RCTs can be expensive; one study found 28 Phase III RCTs funded by the National Institute of Neurological Disorders and Stroke prior to 2000 with a total cost of US$335 million, for a mean cost of US$12 million per RCT. Nevertheless, the return on investment of RCTs may be high, in that the same study projected that the 28 RCTs produced a "net benefit to society at 10-years" of 46 times the cost of the trials program, based on evaluating a quality-adjusted life year as equal to the prevailing mean per capita gross domestic product. The conduct of an RCT takes several years until being published; thus, data is restricted from the medical community for long years and may be of less relevance at time of publication. It is costly to maintain RCTs for the years or decades that would be ideal for evaluating some interventions. Interventions to prevent events that occur only infrequently (e.g., sudden infant death syndrome) and uncommon adverse outcomes (e.g., a rare side effect of a drug) would require RCTs with extremely large sample sizes and may, therefore, best be assessed by observational studies. Due to the costs of running RCTs,


id: randomized-controlled-trial-20260505-6
file: data/en.wikipedia.org/wiki/Randomized_controlled_trial-6.md
category: reference
title: Randomized controlled trial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Randomized_controlled_trial
date_saved: 2026-05-05T10:02:58.342301+00:00
instance: kb-cron
parent: randomized-controlled-trial-20260505-0
summary:
=== Economics === RCTs have become a staple of identifying causal inference among microeconomic studies, particularly in development economics. In 1994, Paul Glewwe, eventual Nobel Prize winner, Michael Kremer, and Sylvie Moulin started one of the earliest RCTs in an economic setting by conducting a long run intervention in a school in Kenya, publishing the results fifteen years later. Three years later in 1997, the largest field experiment in a developing context, the PROGRESA program in Mexico, was studied by a multitude of economic researchers. The impact of RCTs on the discipline has only grown, as economists have found this method as a first-best approach to causal inference identification. While not at the forefront, the use of RCTs has helped to bolster the credibility revolution in empirical microeconomics, as well as becoming popularized as a result of the need for more rigorous identification. Despite the shift towards using RCTs in research, there still remains division between economists on its use. John A. List, a proponent of field experiments, particularly RCTs, finds that this method differs significantly from lab experiments, and therefore provide more robust measures for identification. RCTs also offer the advantage of providing true observational data that can be


id: rapid-reviews-20260505-0
file: data/en.wikipedia.org/wiki/Rapid_reviews-0.md
category: reference
title: Rapid reviews
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rapid_reviews
date_saved: 2026-05-05T10:02:59.617551+00:00
instance: kb-cron
parent: rapid-reviews-20260505-0
summary:
Rapid reviews are a systematic survey of literature on a topic or question of interest. Compared to a systematic review of literature, in a rapid review, several design decisions and practical steps are undertaken to reduce the time it takes to identify, aggregate and answer the question of interest. The Cochrane Rapid Reviews Methods Group proposes that rapid reviews can take different forms, and they define rapid reviews as: "A form of knowledge synthesis that accelerates the process of conducting a traditional systematic review through streamlining or omitting specific methods to produce evidence for stakeholders in a resource-efficient manner". == In medicine and healthcare == Rapid reviews are a form of evidence synthesis, similar to a systematic review, that can be used to inform decision-making and healthcare initiative. The World Health Organization (WHO) considers rapid reviews as a way of generating evidence in a short period using an abbreviated systematic review method. During the COVID-19 pandemic rapid reviews were employed to answer pressing questions under strict time constraints. == In software engineering == For Software Engineering, Rico et al. have recently adapted and extended the rapid review method. Their proposal takes into account the unique requirements of industry-academia collaboration in


id: reporting-bias-20260505-0
file: data/en.wikipedia.org/wiki/Reporting_bias-0.md
category: reference
title: Reporting bias
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reporting_bias
date_saved: 2026-05-05T10:03:00.766807+00:00
instance: kb-cron
parent: reporting-bias-20260505-0
summary:
In epidemiology, reporting bias is defined as "selective revealing or suppression of information" by subjects (for example about past medical history, smoking, sexual experiences). In artificial intelligence research, the term reporting bias is used to refer to people's tendency to under-report all the information available. In empirical research, authors may be under-reporting unexpected or undesirable experimental results, attributing the results to sampling or measurement error, while being more trusting of expected or desirable results, though these may be subject to the same sources of error. In this context, reporting bias can eventually lead to a status quo where multiple investigators discover and discard the same results, and later experimenters justify their own reporting bias by observing that previous experimenters reported different results. Thus, each incident of reporting bias can make future incidents more likely. == Reporting biases in research == Research can only contribute to knowledge if it is communicated from investigators to the community. The generally accepted primary means of communication is "full" publication of the study methods and results in an article published in a scientific journal. Sometimes, investigators choose to present their findings at a scientific meeting as well, either through an oral or poster presentation. These


id: reporting-bias-20260505-1
file: data/en.wikipedia.org/wiki/Reporting_bias-1.md
category: reference
title: Reporting bias
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reporting_bias
date_saved: 2026-05-05T10:03:00.766807+00:00
instance: kb-cron
parent: reporting-bias-20260505-0
summary:
The publication or nonpublication of research findings, depend on the nature and direction of the results. Although medical writers have acknowledged the problem of reporting biases for over a century, it was not until the second half of the 20th century that researchers began to investigate the sources and size of the problem of reporting biases. Over the past two decades, evidence has accumulated that failure to publish research studies, including clinical trials testing intervention effectiveness, is pervasive. Almost all failure to publish is due to failure of the investigator to submit; only a small proportion of studies are not published because of rejection by journals. Some reviews have reported that only half or all trials are published. The most direct evidence of publication bias in the medical field comes from follow-up studies of research projects identified at the time of funding or ethics approval. These studies have shown that "positive findings" is the principal factor associated with subsequent publication: researchers say that the reason they do not write up and submit reports of their research for publication is usually because they are "not interested" in the results (editorial rejection by journals is a rare cause of failure to publish).


id: reporting-bias-20260505-2
file: data/en.wikipedia.org/wiki/Reporting_bias-2.md
category: reference
title: Reporting bias
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reporting_bias
date_saved: 2026-05-05T10:03:00.766807+00:00
instance: kb-cron
parent: reporting-bias-20260505-0
summary:
Bias –also known as spin- in research reporting interventional medical studies could arise from, misleading reporting, misleading interpretation and inadequate extrapolation of the results or conclusions. Research reporting bias can take various forms. Misleading reporting could be attributed to failure to report adverse effects of a certain medical or surgical intervention, selective reporting of results, or inappropriate use of language in the conclusions as overstated conclusions or undue generalizations that are not supported by study's results. Misleading interpretation of research results could be attributed to misinterpretation of both statistically significant and statistically non-significant etcetera. Inadequate extrapolation of research results could be caused by extending the positive outcomes of research to include a broader or different patient population that was not originally investigated. The selective reporting of some outcomes but not others, depending on the nature and direction of the results. A study may be published in full, but pre-specified outcomes omitted or misrepresented. Efficacy outcomes that are statistically significant have a higher chance of being fully published compared to those that are not statistically significant. Research interpretation bias or spin is prevalent across medical publications irrespective of discipline i.e. surgical versus medical and irrespective of journal ranking or study's level-of-evidence


id: research-synthesis-20260505-0
file: data/en.wikipedia.org/wiki/Research_synthesis-0.md
category: reference
title: Research synthesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Research_synthesis
date_saved: 2026-05-05T10:03:01.946663+00:00
instance: kb-cron
parent: research-synthesis-20260505-0
summary:
Research synthesis or evidence synthesis is the process of combining the results of multiple primary research studies aimed at testing the same conceptual hypothesis. It may be applied to either quantitative or qualitative research. Its general goals are to make the findings from multiple different studies more generalizable and applicable. It aims to generate new knowledge by combining and comparing the results of multiple studies on a given topic. One approach is to use a systematic review method. == Techniques == Meta-analysis is the preferred technique of quantitative research synthesis in many fields, such as medical science. It is a statistical technique that combines measures of effect size from a number of studies to calculate an overall measure. This measure of effect has greater precision (less uncertainty) than the individual studies, but it may be biased by differences between the studies in study design, the type of evidence, or other key characteristics. In qualitative research, methods of synthesis include narrative synthesis and meta-ethnography. Narrative synthesis allows researchers to address a wide range of questions in their review, while meta-ethnography aims to preserve the cultural context in which the original findings of the included studies were generated. The narrative synthesis approach


id: reverse-correlation-technique-20260505-0
file: data/en.wikipedia.org/wiki/Reverse_correlation_technique-0.md
category: reference
title: Reverse correlation technique
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reverse_correlation_technique
date_saved: 2026-05-05T10:03:03.129594+00:00
instance: kb-cron
parent: reverse-correlation-technique-20260505-0
summary:
The reverse correlation technique is a data driven study method used primarily in psychological and neurophysiological research. This method earned its name from its origins in neurophysiology, where cross-correlations between white noise stimuli and sparsely occurring neuronal spikes could be computed quicker when only computing it for segments preceding the spikes. The term has since been adopted in psychological experiments that usually do not analyze the temporal dimension, but also present noise to human participants. In contrast to the original meaning, the term is here thought to reflect that the standard psychological practice of presenting stimuli of defined categories to the participants is "reversed": Instead, the participant's mental representations of categories are estimated from interactions of the presented noise and the behavioral responses. It is used to create composite pictures of individual and/or group mental representations of various items (e.g. faces, bodies, and the self) that depict characteristics of said items (e.g. trustworthiness and self-body image). This technique is helpful when evaluating the mental representations of those with and without mental illnesses. == Terms == This technique utilizes spike-triggered average to explain what areas of signal and noise in an image are valuable for the given research question. Signal is


id: reverse-correlation-technique-20260505-1
file: data/en.wikipedia.org/wiki/Reverse_correlation_technique-1.md
category: reference
title: Reverse correlation technique
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reverse_correlation_technique
date_saved: 2026-05-05T10:03:03.129594+00:00
instance: kb-cron
parent: reverse-correlation-technique-20260505-0
summary:
=== Step 1: making stimuli === When designing the stimuli for a reverse correlation study, the two primary factors that one should consider are (1) the base image and (2) the noise that will be used. While not all bases are images per se, the majority are and for this reason the base is typically referred to as a base image. The base image should represent whatever the research question is addressing. For example, if you are interested in peoples’ mental representations of Chinese people, it would not make sense to use a base image of a Spanish or Caucasian person. Again, if you are interested in the mental representations of male vocal patterns, it would make the most sense to use a base vocal pattern that has been produced by a male. Having a base is important because it provides a kind of anchor for participants to work from. When there is no base image, the number of trials that are required increases dramatically, thus making it harder to collect data. While there are studies that have excluded a base image, (e.g. the S study), for more elaborate and nuanced research questions, it is important to have a base


id: reverse-correlation-technique-20260505-2
file: data/en.wikipedia.org/wiki/Reverse_correlation_technique-2.md
category: reference
title: Reverse correlation technique
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reverse_correlation_technique
date_saved: 2026-05-05T10:03:03.129594+00:00
instance: kb-cron
parent: reverse-correlation-technique-20260505-0
summary:
=== Step 2: data collection === Once the stimuli for the study has been developed, the researcher must make a few decisions before actually collecting the data. The researcher must come to a conclusion on how many stimuli will be presented at a time and how many trials the participants will see. In terms of stimuli presentation, a researcher can choose from either a 2-Image Forced Choice (2IFC) or a 4-Alternative Forced Choice (4AFC). The 2IFC presents two images at once (side by side) and requires participants to choose between the two on a specified category (e.g. which image looks the most like a male). Typically the noise from the left image is the mathematical inverse of the noise from the right image. This method was developed to better answer questions that could not be fully answered by the 4AFC method. As compared to the 2IFC, the 4AFC only shows participants one image per trial and requires them to rate the image on a 4-point scale ((1) Probably X, (2) Possibly X, (3) Possibly Y, (4) Probably Y). For example, here X might represent male and Y might represent female. Typically, during data analysis, only images that are chosen as


id: reverse-correlation-technique-20260505-3
file: data/en.wikipedia.org/wiki/Reverse_correlation_technique-3.md
category: reference
title: Reverse correlation technique
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reverse_correlation_technique
date_saved: 2026-05-05T10:03:03.129594+00:00
instance: kb-cron
parent: reverse-correlation-technique-20260505-0
summary:
=== Step 4: evaluating classification images and drawing conclusions === After computing classification images for individual participants and/or for the group, the researcher will use these images to draw conclusions about their research questions. However, while not always the case, occasionally after the first set of classification images have been generated, researchers will then take these images and present them to a new sample of participants and ask them to rate the images on a subsequent factor of interest. This process is referred to as a two-phase reverse correlation. For example, if a classification image was computed after participants were asked to choose the image that looked the most like a police officer, the generated classification images could then be presented to a new sample who would evaluate the images on how aggressive the faces look. This process makes it easier to draw conclusions on the data. While this step can ease in drawing conclusions, one must use caution to not collect too many participants in the second phase, because high numbers of participants will make the tiniest of differences appear significant, therefore resulting in a Type 1 Error. While reverse correlation is typically used to create a visual representation


id: secondary-research-20260505-0
file: data/en.wikipedia.org/wiki/Secondary_research-0.md
category: reference
title: Secondary research
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Secondary_research
date_saved: 2026-05-05T10:03:04.325479+00:00
instance: kb-cron
parent: secondary-research-20260505-0
summary:
Secondary research involves the summary, collation and/or synthesis of existing research. Secondary research is contrasted with primary research in that primary research involves the generation of data, whereas secondary research uses primary research sources as a source of data for analysis. A notable marker of primary research is the inclusion of a "methods" section, where the authors describe how the data was generated. Common examples of secondary research include textbooks, encyclopedias, news articles, review articles, and meta analyses. When conducting secondary research, authors may draw data from published academic papers, government documents, statistical databases, and historical records. == Fields == The term is widely used in fields such as history, legal research, market research, and Wikipedia editing. The principal methodology in health secondary research is the systematic review, commonly using meta-analytic statistical techniques. Other methods of synthesis, like realist reviews and meta-narrative reviews, have been developed in the 21st century. Secondary market research includes the reuse by a second party of any data collected from a first party such as telephone interviews or surveys. Secondary market research can be broken up into two categories: information from internal sources such as an agency or company, and information from external sources held


id: single-arm-study-design-20260505-0
file: data/en.wikipedia.org/wiki/Single-arm_study_design-0.md
category: reference
title: Single-arm study design
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Single-arm_study_design
date_saved: 2026-05-05T10:03:05.523833+00:00
instance: kb-cron
parent: single-arm-study-design-20260505-0
summary:
A single-arm study design is a type of clinical or experimental study where all participants receive the same intervention, with no control or placebo group. The term "single-arm" refers to the presence of only one participant group, in contrast to designs such as randomized controlled trials, which include both a treatment arm and control or placebo arm. == Overview == Single-arm trials include one experimental group without the inclusion of a parallel control group. The design is open-label and does not involve randomization or blinding. This type of study design is commonly applied to advance stage cancer, rare diseases, emerging infectious diseases, new treatment methods, and medical devices. While randomized control trials are considered the “gold standard” in clinical research, they are not always feasible due to limitations in the study population, challenges in obtaining evidence, high costs, and ethical considerations. As a result, single arm trials are used to address these concerns. == Applications == Since there is no randomization in single-arm trials, all patients receive the same intervention within a particular study/trial. This design is most commonly used in early-phase clinical trials or in studies of rare or serious diseases, where including a control group may be impractical


id: society-for-research-synthesis-methodology-20260505-0
file: data/en.wikipedia.org/wiki/Society_for_Research_Synthesis_Methodology-0.md
category: reference
title: Society for Research Synthesis Methodology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Society_for_Research_Synthesis_Methodology
date_saved: 2026-05-05T10:03:20.474390+00:00
instance: kb-cron
parent: society-for-research-synthesis-methodology-20260505-0
summary:
The Society for Research Synthesis Methodology (abbreviated SRSM) is an international, interdisciplinary learned society dedicated to promoting and fostering the study of research synthesis: the process whereby the results of multiple scientific studies are combined. It was founded in November 2005, with its organizational meeting held on November 11 and 12 of that year. It has 85 active members. Its official journal is Research Synthesis Methods, which has been published by Wiley since 2010. It holds annual meetings every summer for members (and occasionally nonmembers) to present their research. The president for the 2024–2025 term is Ian Shrier, and the president-elect is James Pustejovsky. == Past presidents == Terri Pigott (2023-24) Tianjing Li (2022–23) Georgia Salanti (2021–22) Jack Vevea (2019–21) Christopher H. Schmid (2018–19) Michael Borenstein (2017–18) Kay Dickersin (2016–17) Jessica Gurevitch (2015–16) Lesley Stewart (2014–15) William Shadish (2013–14) Hannah Rothstein (2012–13) Jesse Berlin (2011–12) David Jones (2010–11) John Ioannidis (2009–10) Larry V. Hedges (2008–09) Alex Sutton (2007–08) Betsy Becker (2006–07) Julian Higgins (2005–06) == References == == External links == Official website


id: springer-protocols-20260505-0
file: data/en.wikipedia.org/wiki/Springer_Protocols-0.md
category: reference
title: Springer Protocols
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Springer_Protocols
date_saved: 2026-05-05T10:03:21.647080+00:00
instance: kb-cron
parent: springer-protocols-20260505-0
summary:
Springer Protocols was a database of life sciences protocols published by Springer Science+Business Media. It replaced BioMed Protocols, a Humana Press database, in January 2008, and was deactivated on 25 July 2018. The protocols were then available on the SpringerLink website. The protocols are "recipes" that allow scientists to recreate experiments in their own laboratory. Springer Protocols contained more than 33,000 protocols, most of which were derived from the book series Methods in Molecular Biology, published under the Humana Press imprint. That book series, edited by John M. Walker since 1984, contains more than 1,100 volumes and has spawned several related book series. == Areas of study == Springer Protocols consisted of protocols from many Humana Press book series, most notably Methods in Molecular Biology, Methods in Molecular Medicine, Methods in Biotechnology, Methods in Pharmacology and Toxicology, and Neuromethods. Among the subjects covered were biochemistry, bioinformatics, biotechnology, cancer research, cell biology, genetics/genomics, imaging/radiology, immunology, infectious diseases, microbiology, molecular medicine, neuroscience, pharmacology/toxicology, plant science, and protein science. == Website specifics == The website was hosted by online journal provider MPS Technologies’ JournalStore platform. Among the features on the site were full-text indexing, RSS feeds, bookmarks, saved searches, comments sections for each


id: statistics-20260505-0
file: data/en.wikipedia.org/wiki/Statistics-0.md
category: reference
title: Statistics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Statistics
date_saved: 2026-05-05T10:03:22.837991+00:00
instance: kb-cron
parent: statistics-20260505-0
summary:
Statistics (from German: Statistik, orig. "description of a state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model to be studied. Populations can be diverse groups of people or objects such as "all people living in a country" or "every atom composing a crystal". Statistics deals with every aspect of data, including the planning of data collection in terms of the design of surveys and experiments. Statistics is deeply related to subjects like physics, chemistry, geography, geopolitics, and especially mathematics. When census data (comprising every member of the target population) cannot be collected, statisticians collect data by developing specific experiment designs and survey samples. Representative sampling assures that inferences and conclusions can reasonably extend from the sample to the population as a whole. An experimental study involves taking measurements of the system under study, manipulating the system, and then taking additional measurements using the same procedure to determine if the manipulation has modified the values of the measurements. In contrast, an observational study does not involve experimental manipulation. Two main


id: statistics-20260505-1
file: data/en.wikipedia.org/wiki/Statistics-1.md
category: reference
title: Statistics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Statistics
date_saved: 2026-05-05T10:03:22.837991+00:00
instance: kb-cron
parent: statistics-20260505-0
summary:
==== Sampling ==== When full census data cannot be collected, statisticians collect sample data by developing specific experiment designs and survey samples. Statistics itself also provides tools for prediction and forecasting through statistical models. To use a sample as a guide to an entire population, it is important that it truly represents the overall population. Representative sampling ensures that inferences and conclusions can safely be extended from the sample to the population as a whole. A major problem lies in determining the extent to which the chosen sample is actually representative. Statistics offers methods to estimate and correct for any bias in the sample and data collection procedures. There are also methods of experimental design that can lessen these issues at the outset of a study, strengthening its ability to discern truths about the population. Sampling theory is part of the mathematical discipline of probability theory. Probability is used in mathematical statistics to study the sampling distributions of sample statistics and, more generally, the properties of statistical procedures. The use of any statistical method is valid only when the system or population under consideration satisfies the assumptions of the method. The difference in point of view between classic probability theory


id: statistics-20260505-2
file: data/en.wikipedia.org/wiki/Statistics-2.md
category: reference
title: Statistics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Statistics
date_saved: 2026-05-05T10:03:22.837991+00:00
instance: kb-cron
parent: statistics-20260505-0
summary:
Various attempts have been made to produce a taxonomy of levels of measurement. The psychophysicist Stanley Smith Stevens defined nominal, ordinal, interval, and ratio scales. Nominal measurements do not have meaningful rank order among values, and permit any one-to-one (injective) transformation. Ordinal measurements have imprecise differences between consecutive values, but have a meaningful order to those values, and permit any order-preserving transformation. Interval measurements have meaningful distances between measurements defined, but the zero value is arbitrary (as in the case with longitude and temperature measurements in Celsius or Fahrenheit), and permit any linear transformation. Ratio measurements have both a meaningful zero value and the distances between different measurements defined, and permit any rescaling transformation. Because variables conforming only to nominal or ordinal measurements cannot be reasonably measured numerically, sometimes they are grouped together as categorical variables, whereas ratio and interval measurements are grouped together as quantitative variables, which can be either discrete or continuous, due to their numerical nature. Such distinctions can often be loosely correlated with data type in computer science, in that dichotomous categorical variables may be represented with the Boolean data type, polytomous categorical variables with arbitrarily assigned integers in the integral data type, and continuous variables


id: statistics-20260505-3
file: data/en.wikipedia.org/wiki/Statistics-3.md
category: reference
title: Statistics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Statistics
date_saved: 2026-05-05T10:03:22.837991+00:00
instance: kb-cron
parent: statistics-20260505-0
summary:
===== Null hypothesis and alternative hypothesis ===== Interpretation of statistical information can often involve the development of a null hypothesis which is usually (but not necessarily) that no relationship exists among variables or that no change occurred over time. The alternative hypothesis is the name of the hypothesis that contradicts the null hypothesis. The best illustration for a novice is the predicament encountered by a criminal trial. The null hypothesis, H0, asserts that the defendant is innocent, whereas the alternative hypothesis, H1, asserts that the defendant is guilty. The indictment comes because of suspicion of the guilt. The H0 (the status quo) stands in opposition to H1 and is maintained unless H1 is supported by evidence "beyond a reasonable doubt". However, "failure to reject H0" in this case does not imply innocence, but merely that the evidence was insufficient to convict. So the jury does not necessarily accept H0 but fails to reject H0. While one can not "prove" a null hypothesis, one can test how close it is to being true with a power test, which tests for type II errors. The null hypothesis cannot be proven true because it is already assumed to be true when the test


id: statistics-20260505-4
file: data/en.wikipedia.org/wiki/Statistics-4.md
category: reference
title: Statistics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Statistics
date_saved: 2026-05-05T10:03:22.837991+00:00
instance: kb-cron
parent: statistics-20260505-0
summary:
The standard approach is to test a null hypothesis against an alternative hypothesis. A critical region is the set of values of the estimator that leads to refuting the null hypothesis. The probability of type I error is therefore the probability that the estimator belongs to the critical region given that null hypothesis is true (statistical significance) and the probability of type II error is the probability that the estimator does not belong to the critical region given that the alternative hypothesis is true. The statistical power of a test is the probability that it correctly rejects the null hypothesis when the null hypothesis is false. Referring to statistical significance does not necessarily mean that the overall result is significant in real-world terms. For example, in a large study of a drug it may be shown that the drug has a statistically significant but very small beneficial effect, such that it is unlikely to help the patient noticeably. Although in principle the acceptable level of statistical significance may be subject to debate, the significance level is the largest p-value that allows the test to reject the null hypothesis. This test is logically equivalent to saying that the p-value is the


id: statistics-20260505-5
file: data/en.wikipedia.org/wiki/Statistics-5.md
category: reference
title: Statistics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Statistics
date_saved: 2026-05-05T10:03:22.837991+00:00
instance: kb-cron
parent: statistics-20260505-0
summary:
The mathematical foundations of statistics developed from discussions concerning games of chance among mathematicians such as Gerolamo Cardano, Blaise Pascal, Pierre de Fermat, and Christiaan Huygens. Although the idea of probability was already examined in ancient and medieval law and philosophy (such as the work of Juan Caramuel), probability theory as a mathematical discipline only took shape at the very end of the 17th century, particularly in Jacob Bernoulli's posthumous work Ars Conjectandi. This was the first book where the realm of games of chance and the realm of the probable (which concerned opinion, evidence, and argument) were combined and submitted to mathematical analysis. The method of least squares was first described by Adrien-Marie Legendre in 1805, though Carl Friedrich Gauss presumably made use of it a decade earlier in 1795. In the 1830s-1850s, "statistical offices" and national "statistical societies" were founded in Europe and America, and in the mid-19th century, the idea arose of "organized contacts between the statisticians of different countries although informal contacts occurred earlier". In those days, the name "statistics" referred mainly to "matters of state", and British statisticians were often called "statists". Belgian scientist Adolphe Quetelet (1796–1874) introduced the notion of the "average man" (l'homme


id: statistics-20260505-6
file: data/en.wikipedia.org/wiki/Statistics-6.md
category: reference
title: Statistics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Statistics
date_saved: 2026-05-05T10:03:22.837991+00:00
instance: kb-cron
parent: statistics-20260505-0
summary:
=== Statistics in academia === Statistics is applicable to a wide variety of academic disciplines, including natural and social sciences, government, and business. Business statistics applies statistical methods in econometrics, auditing and production and operations, including services improvement and marketing research. A study of two journals in tropical biology found that the 12 most frequent statistical tests are: analysis of variance (ANOVA), chi-squared test, Student's t-test, linear regression, Pearson's correlation coefficient, Mann-Whitney U test, Kruskal-Wallis test, Shannon's diversity index, Tukey's range test, cluster analysis, Spearman's rank correlation coefficient and principal component analysis. A typical statistics course covers descriptive statistics, probability, binomial and normal distributions, test of hypotheses and confidence intervals, linear regression, and correlation. Modern fundamental statistical courses for undergraduate students focus on correct test selection, results interpretation, and use of free statistics software. === Statistical computing === The rapid and sustained increases in computing power starting from the second half of the 20th century have had a substantial impact on the practice of statistical science. Early statistical models were almost always from the class of linear models, but powerful computers, coupled with suitable numerical algorithms, caused an increased interest in nonlinear models (such as neural networks) as well as


id: statistics-20260505-7
file: data/en.wikipedia.org/wiki/Statistics-7.md
category: reference
title: Statistics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Statistics
date_saved: 2026-05-05T10:03:22.837991+00:00
instance: kb-cron
parent: statistics-20260505-0
summary:
Who says so? (Do they have an axe to grind?) How do they know? (Do they have the resources to know the facts?) What's missing? (Do they give us a complete picture?) Did someone change the subject? (Do they offer us the right answer to the wrong problem?) Does it make sense? (Is their conclusion logical and consistent with what we already know?) === Misinterpretation: correlation === The concept of correlation is particularly noteworthy for the potential confusion it can cause. Statistical analysis of a data set often reveals that two variables (properties) of the population under consideration tend to vary together, as if they were connected. For example, a study of annual income that also looks at age of death, might find that poor people tend to have shorter lives than affluent people. The two variables are said to be correlated; however, they may or may not be the cause of one another. The correlation phenomena could be caused by a third, previously unconsidered phenomenon, called a lurking variable or confounding variable. For this reason, there is no way to immediately infer the existence of a causal relationship between the two variables. == See also == Foundations and major


id: storm-chasing-20260505-0
file: data/en.wikipedia.org/wiki/Storm_chasing-0.md
category: reference
title: Storm chasing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storm_chasing
date_saved: 2026-05-05T10:03:24.090775+00:00
instance: kb-cron
parent: storm-chasing-20260505-0
summary:
Storm chasing is broadly defined as the deliberate pursuit of any severe weather phenomenon, regardless of motive, but most commonly for curiosity, adventure, scientific investigation, or for news or media coverage. A person who chases storms is known as a storm chaser (or "chaser" for short). While witnessing a tornado is the single biggest objective for most chasers, many chase thunderstorms and delight in viewing cumulonimbus and related cloud structures, watching a barrage of hail and lightning, and seeing what skyscapes unfold. A smaller number of storm chasers attempt to intercept tropical cyclones, waterspouts, blizzards, ice storms, and other weather phenomena. == Nature of and motivations for chasing == Storm chasing is chiefly a recreational endeavor, with chasers usually giving their motives as photographing or video recording a storm, or for various personal reasons. These can include the beauty of the views afforded by the sky and land, the mystery of not knowing precisely what will unfold, the journey to an undetermined destination on the open road, intangible experiences such as feeling one with a much larger and more powerful natural world, the challenge of correctly forecasting and intercepting storms with optimal vantage points, and pure thrill seeking. Some chasers


id: storm-chasing-20260505-1
file: data/en.wikipedia.org/wiki/Storm_chasing-1.md
category: reference
title: Storm chasing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storm_chasing
date_saved: 2026-05-05T10:03:24.090775+00:00
instance: kb-cron
parent: storm-chasing-20260505-0
summary:
The first person to gain public recognition as a storm chaser was David Hoadley (born 1938), who began chasing North Dakota storms in 1956, systematically using data from area weather offices and airports. He is widely considered the pioneer storm chaser and was the founder and first editor of Storm Track magazine. Neil B. Ward (1914–1972) subsequently brought research chasing to the forefront in the 1950s and 1960s, enlisting the help of the Oklahoma Highway Patrol to study storms. His work pioneered modern storm spotting and made institutional chasing a reality. The first coordinated storm chasing activity sponsored by institutions was undertaken as part of the Alberta Hail Studies project beginning in 1969. Vehicles were outfitted with various meteorological instrumentation and hail-catching apparatus and were directed into suspected hail regions of thunderstorms by a controller at a radar site. The controller communicated with the vehicles by radio. In 1972, the University of Oklahoma (OU) in cooperation with the National Severe Storms Laboratory (NSSL) began the Tornado Intercept Project, with the first outing taking place on 19 April of that year. This was the first large-scale tornado chasing activity sponsored by an institution. It culminated in a brilliant success in 1973


id: storm-chasing-20260505-2
file: data/en.wikipedia.org/wiki/Storm_chasing-2.md
category: reference
title: Storm chasing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storm_chasing
date_saved: 2026-05-05T10:03:24.090775+00:00
instance: kb-cron
parent: storm-chasing-20260505-0
summary:
== Geographical, seasonal, and diurnal activity == Storm chasers are most active in the spring and early summer, particularly May and June, across the Great Plains of the United States (extending into Canada) in an area colloquially known as Tornado Alley, with many hundred individuals active on some days during this period. This coincides with the most consistent tornado days in the most desirable topography of the Great Plains. Not only are the most intense supercells common there, but due to the moisture profile of the atmosphere the storms tend to be more visible than locations farther east where there are also frequent severe thunderstorms. There is a tendency for chases earlier in the year to be farther south, shifting farther north with the jet stream as the season progresses. Storms occurring later in the year tend to be more isolated and slower moving, both of which are also desirable to chasers. Chasers may operate whenever significant thunderstorm activity is occurring, whatever the date. This most commonly includes more sporadic activity occurring in warmer months of the year bounding the spring maximum, such as the active month of April and to a lesser extent March. The focus in the summer


id: storm-chasing-20260505-3
file: data/en.wikipedia.org/wiki/Storm_chasing-3.md
category: reference
title: Storm chasing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storm_chasing
date_saved: 2026-05-05T10:03:24.090775+00:00
instance: kb-cron
parent: storm-chasing-20260505-0
summary:
=== Incidents === For nearly sixty years, the only known chaser deaths were driving-related. As of 25 December 2025, there are four known direct storm chasing deaths and twelve indirect deaths. Nearly half of the indirect deaths are a result of hydroplaning in conditions after a chase. The first was Christopher Phillips, a University of Oklahoma (OU) undergraduate student, who died in a hydroplaning accident when swerving to miss a rabbit in 1984. Other incidents included Jeff Wear driving home in East Texas from a Hurricane Dennis chase in 2005, and Fabian Guerra swerving to miss a deer while driving to a chase on I-80 in Iowa in 2009. A wrong-way driver resulted in a head-on collision that killed Andy Gabrielson who was on the Turner Turnpike (I-44) near Sapulpa, Oklahoma, returning to Luverne, Minnesota, from a chase in 2012. On 31 May 2013, an extreme event led to the first known chaser deaths inflicted directly by weather when the widest tornado ever recorded struck near El Reno, Oklahoma. Engineer Tim Samaras, his photographer son Paul, and meteorologist Carl Young were killed on a rural road by the tornado while doing in situ probe and infrasonic field research. An amateur


id: storm-chasing-20260505-4
file: data/en.wikipedia.org/wiki/Storm_chasing-4.md
category: reference
title: Storm chasing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storm_chasing
date_saved: 2026-05-05T10:03:24.090775+00:00
instance: kb-cron
parent: storm-chasing-20260505-0
summary:
Historically, storm chasing relied on either in-field analysis or in some cases nowcasts from trained observers and forecasters. The first in-field technology consisted of radio gear for communication. Much of this equipment could also be adapted to receive radiofax data which was useful for receiving basic observational and analysis data. The primary users of such technology were university or government research groups who often had larger budgets than individual chasers. Radio scanners were also heavily used to listen in on emergency services and storm spotters so as to determine where the most active or dangerous weather was located. A number of chasers were also radio amateurs, and used mobile (or portable) amateur radio to communicate directly with spotters and other chasers, allowing them to keep abreast of what they could not themselves see. It was not until the mid- to late 1980s that the evolution of the laptop computer would begin to revolutionize storm chasing. Early on, some chasers carried acoustic couplers to download batches of raw surface and upper air data from payphones. The technology was too slow for graphical imagery such as radar and satellite data; and during the first years this wasn't available on any connection over


id: storm-chasing-20260505-5
file: data/en.wikipedia.org/wiki/Storm_chasing-5.md
category: reference
title: Storm chasing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storm_chasing
date_saved: 2026-05-05T10:03:24.090775+00:00
instance: kb-cron
parent: storm-chasing-20260505-0
summary:
Chasers used paper maps for navigation and some of those now using GPS still use these as a backup or for strategizing with other chasers. Foldable state maps can be used but are cumbersome due to the multitude of states needed and only show major roads. National atlases allow more detail and all states are contained in a single book, with AAA favored and Rand McNally followed by Michelin also used. The preferred atlases due to great detail in rural areas are the "Roads of..." series originally by Shearer Publishing, which first included Texas but expanded to other states such as Oklahoma and Colorado. Covering every state of the union are the DeLorme "Atlas and Gazetteer" series. DeLorme also produced early GPS receivers that connected to laptops and for years was one of two major mapping software creators. DeLorme Street Atlas USA or Microsoft Streets & Trips were used by most chasers until their discontinuations in 2013. Chasers now use Google Maps, Waze, and/or Apple Maps or other web mapping on mobile devices as no comparably robust mapping software emerged although operating systems later implemented the apps Windows Maps and Apple Maps. To ensure mapping availability without an active internet


id: storm-chasing-20260505-6
file: data/en.wikipedia.org/wiki/Storm_chasing-6.md
category: reference
title: Storm chasing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storm_chasing
date_saved: 2026-05-05T10:03:24.090775+00:00
instance: kb-cron
parent: storm-chasing-20260505-0
summary:
Some handsets can be used as WiFi hotspots and wireless cards may also be used to avoid committing a handset to tethering or operating as a hotspot. Some hotspots operate as mobile broadband MNVO devices using any radio spectrum that is both available and is in contract with a service provider. Such devices may expand mobile data range beyond a single carrier's service area and typically can work on month-to-month contracts. Adoption of tablet computers expanded by the early 2010s. 4G LTE was adopted early, when available, and was especially useful for uploading HD video. 5G is used with some chasers selecting carriers based on network coverage. Connected car technology includes Wi-Fi which can be used to augment, or even supplant, connectivity via mobile phones. A gradual uptick of those selecting mirrorless interchangeable-lens cameras (MILCs) began in the mid-2010s. Usage of DSLR for video capture, called HDSLR, is common, although camcorders remain relatively popular due to their greater functionality (many chasers still shoot both). Through the 2020s the use of 8K devices is gradually expanding and by the mid-2020s a few chasers are experimenting with 360-degree video. Chasers also carry common travel articles and vehicle maintenance items, and sometimes first


id: storm-chasing-20260505-7
file: data/en.wikipedia.org/wiki/Storm_chasing-7.md
category: reference
title: Storm chasing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storm_chasing
date_saved: 2026-05-05T10:03:24.090775+00:00
instance: kb-cron
parent: storm-chasing-20260505-0
summary:
== Ethics == A growing number of experienced storm chasers advocate the adoption of a code of ethics in storm chasing featuring safety, courtesy, and objectivity as the backbone. Storm chasing is a highly visible recreational activity (which is also associated with science) that is vulnerable to sensationalist media promotion. Veteran storm chasers Chuck Doswell and Roger Edwards deemed reckless storm chasers as "yahoos". Doswell and Edwards believe poor chasing ethics at TV news stations add to the growth of "yahoo" storm chasing. A large lawsuit was filed against the parent company of The Weather Channel in March 2019 for allegedly keeping on contract storm chaser drivers with a demonstrated pattern of reckless driving which ultimately led to a fatal collision (killing themselves and a storm spotter in the other vehicle) when running a stop sign in Texas in 2017. Edwards and Rich Thompson, among others, also expressed concern about pernicious effects of media profiteering with Matt Crowther, among others, agreeing in principle but viewing sales as not inherently corrupting. Self-policing is predominantly seen as the means to mold the hobby. There is occasional discussion among chasers that at some point government regulation may be imposed due to increasing numbers


id: studying-children-in-context-20260505-0
file: data/en.wikipedia.org/wiki/Studying_Children_in_Context-0.md
category: reference
title: Studying Children in Context
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Studying_Children_in_Context
date_saved: 2026-05-05T10:03:25.259826+00:00
instance: kb-cron
parent: studying-children-in-context-20260505-0
summary:
Studying Children in Context: Theories, Methods, and Ethics is a 1998 book on qualitative research methods for working with young children. It was written by M. Elizabeth Graue and Daniel J. Walsh and published by SAGE Publications. == Notes == == References ==


id: theory-driven-evaluation-20260505-0
file: data/en.wikipedia.org/wiki/Theory-driven_evaluation-0.md
category: reference
title: Theory-driven evaluation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Theory-driven_evaluation
date_saved: 2026-05-05T10:03:26.493485+00:00
instance: kb-cron
parent: theory-driven-evaluation-20260505-0
summary:
Theory-driven evaluation (also theory-based evaluation) is an umbrella term for any approach to program evaluation – quantitative, qualitative, or mixed method – that develops a theory of change and uses it to design, implement, analyze, and interpret findings from an evaluation. More specifically, an evaluation is theory-driven if it: formulates a theory of change using some combination of social science, lived experience, and program-related professionals' expertise; develops and prioritizes evaluation questions using the theory; uses the theory to guide the design and implementation of the evaluation; uses the theory to operationalize contextual, process, and outcome variables; provides a causal explanation of how and why outcomes were achieved, including whether the program worked and/or had any unintended consequences (desirable or harmful); and explains what factors moderate outcomes. By investigating the mechanisms leading to outcomes, theory-driven approaches facilitate learning to improve programs and how they are implemented, and help knowledge to accumulate – including across ostensibly different programs. This is in contrast to methods-driven "black box" evaluations, which focus on following the steps of a method (for instance, randomized experiment or focus group) and only assess whether a program achieves its intended outcomes. Theory-driven approaches can also improve the validity of evaluations,


id: theory-driven-evaluation-20260505-1
file: data/en.wikipedia.org/wiki/Theory-driven_evaluation-1.md
category: reference
title: Theory-driven evaluation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Theory-driven_evaluation
date_saved: 2026-05-05T10:03:26.493485+00:00
instance: kb-cron
parent: theory-driven-evaluation-20260505-0
summary:
The target population includes a specification of who participants are and how they are recruited. The implementing organization (for instance a clinic or school) and its staff of implementers (for instance therapists or teachers) are responsible for allocating resources, training, and delivering the interventions. Intervention and service delivery protocols would include therapy manuals or subject curricula. Associated organizations and community partners refers to organisations other than the implementing organisation. In the case of a psychotherapy intervention, this may include schools or general practitioners who advertise the program or refer beneficiaries to it. Ecological context refers to aspects of the environment, for instance family, friends, co-workers, other students, etc., that may moderate the effects of a program. == Theory-driven methods == The full-range of research methods has been argued to apply. Chen (2015) provides examples using randomized experiments, quasi-experimental designs, process and outcome monitoring, and qualitative methods. Although proponents of theory-driven evaluation are critical of "black box" experiments, Chen and Rossi (1983, p. 292) argue that theory-driven experiments are possible and desirable: [A]dvocates of the black box experimental paradigm often neglect the fact that after randomization exogenous variables are still correlated with outcome variables. Knowing how such exogenous factors affect outcomes


id: trend-analysis-20260505-0
file: data/en.wikipedia.org/wiki/Trend_analysis-0.md
category: reference
title: Trend analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Trend_analysis
date_saved: 2026-05-05T10:03:27.621466+00:00
instance: kb-cron
parent: trend-analysis-20260505-0
summary:
Trend analysis is the practice of collecting information and attempting to spot a pattern. In some fields of study, the term has more formally defined meanings. Although trend analysis is often used to predict future events, it could be used to estimate uncertain events in the past, such as how many ancient kings probably ruled between two dates, based on data such as the average years which other known kings reigned. == Project management == In project management, trend analysis is a mathematical technique that uses historical results to predict future outcome. This is achieved by tracking variances in cost and schedule performance. In this context, it is a project management quality control tool. == Statistics == In statistics, trend analysis often refers to techniques for extracting an underlying pattern of behavior in a time series which would otherwise be partly or nearly completely hidden by noise. If the trend can be assumed to be linear, trend analysis can be undertaken within a formal regression analysis, as described in Trend estimation. If the trends have other shapes than linear, trend testing can be done by non-parametric methods, e.g. Mann-Kendall test, which is a version of Kendall rank correlation coefficient. Smoothing


id: trend-receiver-20260505-0
file: data/en.wikipedia.org/wiki/Trend_Receiver-0.md
category: reference
title: Trend Receiver
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Trend_Receiver
date_saved: 2026-05-05T10:03:28.802758+00:00
instance: kb-cron
parent: trend-receiver-20260505-0
summary:
The Trend Receiver Concept is a method for developing Customer Foresight (Baumgarth, 2018, Lüken 2020, van Deth 2020) and has been overall identified as an approach to develop foresight (Rohrbeck et al. 2015; Schwarz et al. 2018). At the core of the Trend Receiver Concept is the identification of suitable conversation partners, so called Trend Receivers, when developing foresight on the future demands and habits of consumers. “Trend Receivers are individuals who perceive changes and potentials of the new in a specific domain in a highly sensitive and differentiated way”. The concept contributes to a firm's mid and long-term vision and strategy by combining both customers and foresight. The Trend Receiver Concept provides a guideline to identifying suitable individuals (Trend Receivers) and to designing resulting conversations with them. == Characteristics of Trend Receivers == Trend Receivers are very well connected, have profound opinions about what motivates individuals and observe changes in society in a very reflective way. Trend Receivers can further be characterized as follows (Hofmann 2020): Context experience: Trend Receivers have a profound understanding of the specific context due to their consumption and usage experiences and are thus familiar with the motive and value sets of consumers. Self-abstraction ability:


id: virtual-colony-count-20260505-0
file: data/en.wikipedia.org/wiki/Virtual_colony_count-0.md
category: reference
title: Virtual colony count
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Virtual_colony_count
date_saved: 2026-05-05T10:03:29.986616+00:00
instance: kb-cron
parent: virtual-colony-count-20260505-0
summary:
Virtual colony count (VCC) is a kinetic, 96-well microbiological assay originally developed to measure the activity of defensins. It has since been applied to other antimicrobial peptides including LL-37. It utilizes a method of enumerating bacteria called quantitative growth kinetics, which compares the time taken for a bacterial batch culture to reach a threshold optical density with that of a series of calibration curves. The name VCC has also been used to describe the application of quantitative growth kinetics to enumerate bacteria in cell culture infection models. Antimicrobial susceptibility testing (AST) can be done on 96-well plates by diluting the antimicrobial agent at varying concentrations in broth inoculated with bacteria and measuring the minimum inhibitory concentration that results in no growth. However, these methods cannot be used to study some membrane-active antimicrobial peptides, which are inhibited by the broth itself. The virtual colony count procedure takes advantage of this fact by first exposing bacterial cells to the active antimicrobial agent in a low-salt buffer for two hours, then simultaneously inhibiting antimicrobial activity and inducing exponential growth by adding broth. The growth kinetics of surviving cells can then be monitored using a temperature-controlled plate reader. The time taken for each growth


id: virtual-colony-count-20260505-1
file: data/en.wikipedia.org/wiki/Virtual_colony_count-1.md
category: reference
title: Virtual colony count
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Virtual_colony_count
date_saved: 2026-05-05T10:03:29.986616+00:00
instance: kb-cron
parent: virtual-colony-count-20260505-0
summary:
== Virtual colony count == The traditional colony count method could be modified to measure antimicrobial activity in the 96-well plate without the need for sampling the wells and spreading surviving cells on agar plates by simply adding an equal volume of twice-concentrated broth after the two hour incubation in the low salt buffer. There would need to be a way to determine how many cells survived at the end of the incubation period using batch cultures. Fortunately, the mathematics of exponential growth offers a way to do just that. If the turbidity, or optical density, of the batch cultures within the 96-well plate is monitored in real time, and the amount of time required for a well to reach a threshold is recorded, and the doubling time of the exponentially growing cells is known, then the number of cells originally present in the inoculum can be calculated. This starting number of cells is equal to the number of surviving cells at the end of the two hour incubation with the antimicrobial agent. Because this procedure requires no actual colony formation or colony counting, it is termed "virtual colony count". Thus far the VCC technique has been limited to antimicrobial


id: virtual-colony-count-20260505-2
file: data/en.wikipedia.org/wiki/Virtual_colony_count-2.md
category: reference
title: Virtual colony count
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Virtual_colony_count
date_saved: 2026-05-05T10:03:29.986616+00:00
instance: kb-cron
parent: virtual-colony-count-20260505-0
summary:
The method of enumeration of surviving cells used by VCC is termed quantitative growth kinetics (QGK). It relates the kinetic time taken for the turbidity of a bacterial batch microbiological culture in a well of a 96-well microplate to reach a threshold difference in turbidity to a 10-fold dilution series of calibration growth curves. Quantification of the number of viable cells is done using a process mathematically identical to quantitative real-time polymerase chain reaction (QPCR), except with QGK cells, rather than copies of PCR products, grow exponentially. The time taken to reach the threshold is called the "threshold time", Tt, which is equivalent to the QPCR value "cycle time" or Ct. There are at least five processes that cause delays in threshold times in VCC assays: Adhesion, causing cells to stick to the microplate and possibly form biofilms. Unless these cells happen to be directly in the light path, their growth will not affect optical density readings. Cohesion, causing cells to aggregate into clumps of various sizes instead of a homogeneous suspension of individual cells undergoing binary fission. Cohesion can cause imprecision and fluctuations in Tt. Cohesive clumps may also be adhesive, leading to both imprecision due to cohesion and


id: virtual-colony-count-20260505-3
file: data/en.wikipedia.org/wiki/Virtual_colony_count-3.md
category: reference
title: Virtual colony count
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Virtual_colony_count
date_saved: 2026-05-05T10:03:29.986616+00:00
instance: kb-cron
parent: virtual-colony-count-20260505-0
summary:
== Inoculum effect == An inoculum effect has been previously described for many antimicrobial agents, such that the agent is less effective when more bacteria are added to the assay. This effect is often observed with beta lactams when assayed against beta lactamase producing bacteria. The inoculum effect was potentially relevant to a study of HNP1, pro LL-37 and LL-37 that included both traditional colony counting and VCC side by side. In that report, it was found that traditional colony count survival values were less than virtual survival values for all peptides and strains tested. Because the inoculum of bacteria was 20-fold greater in the VCC assay compared to the standardized traditional colony count protocol used, the difference could have been due to an inoculum effect, although the effect would have been the reverse of the inoculum effect normally seen with other antimicrobial agents, since the higher inoculum showed more activity. This possibility was investigated in a series of VCC experiments mainly focusing on the defensin HNP1 and the bacterial strains E. coli, S. aureus and B. cereus. The results of six experiments demonstrated a pronounced inoculum effect of HNP1 against E. coli. == Algorithms to analyze quantitative growth kinetics


id: visual-ethnography-20260505-0
file: data/en.wikipedia.org/wiki/Visual_ethnography-0.md
category: reference
title: Visual ethnography
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Visual_ethnography
date_saved: 2026-05-05T10:03:31.166378+00:00
instance: kb-cron
parent: visual-ethnography-20260505-0
summary:
Visual ethnography is an approach to ethnography (the study of people and cultures) that uses visual methods such as photography, film and video. There are many methods available to conduct visual ethnography. According to Sarah Pink, visual ethnography is a research methodology that brings “theory and practice of visual approaches to learning and knowing about the world and communicating these to others”. As a methodology, visual ethnography can guide the design of research as well as the methods to choose for data collection. Visual ethnography suggests a negotiation of the participants’ view of reality and a constant questioning on the part of the researcher. == Historical development == Beginning in the early 1900s, researchers have recognized the importance of visual methods which has largely emerged from anthropology. That is when photography as well as video became ways of recording targeted populations during field work which are called “salvage ethnography” or “salvage anthropology.” Flaherty's Nanook of the North (1922), Margaret Mead's and Gregory Bateson's video and photos of the Balinese, and Evans-Prichard's photographs of the Nuer are examples of this “salvage ethnography (Pink, 2006, cited in van den Scott, 2018). Boas as explained by Pink was an early user of photography


id: vivisection-20260505-0
file: data/en.wikipedia.org/wiki/Vivisection-0.md
category: reference
title: Vivisection
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Vivisection
date_saved: 2026-05-05T10:03:32.979340+00:00
instance: kb-cron
parent: vivisection-20260505-0
summary:
Vivisection (from Latin vivus 'alive' and sectio 'cutting') is surgery conducted for experimental purposes on a living organism, typically animals with a central nervous system, to view living internal structure. The word is, more broadly, used as a pejorative catch-all term for experimentation on live animals by organizations opposed to animal experimentation, but the term is rarely used by practicing scientists. Human vivisection, such as live organ harvesting, has been perpetrated as a form of torture. == Animal vivisection == === Regulations and laws === Research requiring vivisection techniques that cannot be met through other means is often subject to an external ethics review in conception and implementation, and in many jurisdictions use of anesthesia is legally mandated for any surgery likely to cause pain to any vertebrate. In the United States, the Animal Welfare Act explicitly requires that any procedure that may cause pain use "tranquilizers, analgesics, and anesthetics" with exceptions when "scientifically necessary". The act does not define "scientific necessity" or regulate specific scientific procedures, but approval or rejection of individual techniques in each federally funded lab is determined on a case-by-case basis by the Institutional Animal Care and Use Committee, which contains at least one veterinarian, one


id: vivisection-20260505-1
file: data/en.wikipedia.org/wiki/Vivisection-1.md
category: reference
title: Vivisection
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Vivisection
date_saved: 2026-05-05T10:03:32.979340+00:00
instance: kb-cron
parent: vivisection-20260505-0
summary:
The Cruelty to Animals Act, 1876 in Britain determined that one could only conduct vivisection on animals with the appropriate license from the state, and that the work the physiologist was doing had to be original and absolutely necessary. The stage was set for such legislation by physiologist David Ferrier. Ferrier was a pioneer in understanding the brain and used animals to show that certain locales of the brain corresponded to bodily movement elsewhere in the body in 1873. He put these animals to sleep, and caused them to move unconsciously with a probe. Ferrier was successful, but many decried his use of animals in his experiments. Some of these arguments came from a religious standpoint. Some were concerned that Ferrier's experiments would separate God from the mind of man in the name of science. Some of the anti-vivisection movement in England had its roots in Evangelicalism and Quakerism. These religions already had a distrust for science, only intensified by the recent publishing of Darwin's Theory of Evolution in 1859. Neither side was pleased with how the Cruelty to Animals Act 1876 was passed. The scientific community felt as though the government was restricting their ability to compete with the


id: wildlife-observation-20260505-0
file: data/en.wikipedia.org/wiki/Wildlife_observation-0.md
category: reference
title: Wildlife observation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wildlife_observation
date_saved: 2026-05-05T10:03:34.170673+00:00
instance: kb-cron
parent: wildlife-observation-20260505-0
summary:
Wildlife observation is the practice of noting the occurrence or abundance of animal species at a specific location and time, either for research purposes or recreation. Common examples of this type of activity are bird watching and whale watching. The process of scientific wildlife observation includes the reporting of what (diagnosis of the species), where (geographical location), when (date and time), who (details about observer), and why (reason for observation, or explanations for occurrence). Wildlife observation can be performed if the animals are alive, with the most notable example being face-to-face observation and live cameras, or are dead, with the primary example being the notifying of where roadkill has occurred. This outlines the basic information needed to collect data for a wildlife observation; which can also contribute to scientific investigations of distribution, habitat relations, trends, and movement of wildlife species. Wildlife observation allows for the study of organisms with minimal disturbance to their ecosystem depending on the type of method or equipment used. The use of equipment such as unmanned aerial vehicles (UAVs), more commonly known as drones, may disturb and cause negative impacts on wildlife. Specialized equipment can be used to collect more accurate data. == History == Wildlife


id: wildlife-observation-20260505-1
file: data/en.wikipedia.org/wiki/Wildlife_observation-1.md
category: reference
title: Wildlife observation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wildlife_observation
date_saved: 2026-05-05T10:03:34.170673+00:00
instance: kb-cron
parent: wildlife-observation-20260505-0
summary:
=== Birdwatching === One of the most popular forms of wildlife observation, birdwatching, is typically performed as a recreational pleasure. Those looking to birdwatch typically travel into a forest or other wooded area with a pair of binoculars in hand to aid the process. Birdwatching has become all the more important with the amount of deforestation that has been occurring in the world. Birds are arguably the most important factor in the balance of environmental systems: "They pollinate plants, disperse seeds, scavenge carcasses and recycle nutrients back into the earth." A decrease in the total number of birds would cause destruction to much of the environmental system. The plants and trees around the world would die at an alarming rate which would, in turn, set off a chain reaction that would cause many other animals to die due to the environment change and habitat loss. One of the ways that birdwatching has an effect on the environment as a whole is that through consistent birdwatching, an observer would be able to identify whether they are seeing less of a certain species of bird. If this happens, there typically is a reasons for the occurrence, whether it be because of an


id: wildlife-observation-20260505-2
file: data/en.wikipedia.org/wiki/Wildlife_observation-2.md
category: reference
title: Wildlife observation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wildlife_observation
date_saved: 2026-05-05T10:03:34.170673+00:00
instance: kb-cron
parent: wildlife-observation-20260505-0
summary:
=== Online systems and mobile apps === Many states have already begun to set up websites and systems for the public. The main purpose behind the movement is so that they can notify other individuals about road-killed wildlife. If enough people fill out the forms located on the websites, the government will become notified that there have been occurrences of a loss of animal life and will take the steps required to prevent it. Typically, the step that is taken is the posting of a wildlife crossing sign that, in turn, allows the public to know where there are common animal crossings. Maine and California are the states that have been the pioneers of this movement and this process has become particularly important on heavily traveled roads as no one would like endanger the animals or themselves. Currently, there is an app (available on both iPhone and Android devices) made specifically for the purpose of identifying road-kill called “Mobile Mapper.” The app is a partner of the HerpMapper website. The purpose of the website is to use the user recorded observations for research and conservation purposes. On average, the cost of repairing a car that has been damaged by a


id: wildlife-observation-20260505-3
file: data/en.wikipedia.org/wiki/Wildlife_observation-3.md
category: reference
title: Wildlife observation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wildlife_observation
date_saved: 2026-05-05T10:03:34.170673+00:00
instance: kb-cron
parent: wildlife-observation-20260505-0
summary:
=== Pollution === Pollution is another crucial threat to animal life, and human life, across the world. Every form of pollution has an effect on wildlife, whether it be through the air, water, or ground. While sometimes the origin and form of pollution is visible and easy to determine, other times it can be a mystery as to what exactly is causing the death of animals. Through constant and consistent observation of habitat analysis, humans can help prevent the loss of animal life by recognizing the early signs of pollution before the problem becomes too large. ==== Ocean and water pollution ==== Pollution can enter bodies of water in many different ways - Through toxic runoff from pesticides and fertilizers, containers of oil and other hazardous materials falling off of ships, or just from debris from humans that has not been picked up. No matter what the form of pollution is, the effects water pollution has on animal life can be drastic. For example, the BP oil spill which occurred in 2010 impacted over 82,000 birds, 6,000 sea turtles, approximately 26,000 marine animals, and hundreds of thousands of fish. While the observation of how animal life was and has been


id: wildlife-observation-20260505-4
file: data/en.wikipedia.org/wiki/Wildlife_observation-4.md
category: reference
title: Wildlife observation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wildlife_observation
date_saved: 2026-05-05T10:03:34.170673+00:00
instance: kb-cron
parent: wildlife-observation-20260505-0
summary:
=== Costs that observation prevents === Referring back to the example from the "Deceased Wildlife Observation" section, it becomes apparent how animal observation can save families and the government money. With the average cost of repairing a car that has damage from a large sized animal being $2,000, families and the government could save money by making the public aware that they should proceed with caution in areas where animals have been hit. Additionally, approximately $44 million of the $4.3 billion spent on water purity is spent each year on protecting aquatic species from nutrient pollution. It is encouraging that the government is willing to spend the money to help save animals' lives, sometimes the effects of the pollution take effect before they are able to stop them entirely. One million seabirds and hundred thousand aquatic mammals and fish that are killed as a result of water pollution each year and that has its economic effects, both directly and indirectly. Directly, the loss of aquatic mammals and fish has a direct impact on the sales of food. The EPA estimated recently that the effects of pollution cost the fishing industry tens of millions of dollars in sales. Indirectly, the loss


id: absorption-spectroscopy-20260505-0
file: data/en.wikipedia.org/wiki/Absorption_spectroscopy-0.md
category: reference
title: Absorption spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Absorption_spectroscopy
date_saved: 2026-05-05T10:03:35.666525+00:00
instance: kb-cron
parent: absorption-spectroscopy-20260505-0
summary:
Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating field. The intensity of the absorption varies as a function of frequency, and this variation is the absorption spectrum. Absorption spectroscopy is performed across the electromagnetic spectrum. Absorption spectroscopy is employed as an analytical chemistry tool to determine the presence of a particular substance in a sample and, in many cases, to quantify the amount of the substance present. Infrared and ultraviolet–visible spectroscopy are particularly common in analytical applications. Absorption spectroscopy is also employed in studies of molecular and atomic physics, astronomical spectroscopy and remote sensing. There is a wide range of experimental approaches for measuring absorption spectra. The most common arrangement is to direct a generated beam of radiation at a sample and detect the intensity of the radiation that passes through it. The transmitted energy can be used to calculate the absorption. The source, sample arrangement and detection technique vary significantly depending on the frequency range and the purpose of the experiment. Following are the major types of absorption spectroscopy: ==


id: absorption-spectroscopy-20260505-1
file: data/en.wikipedia.org/wiki/Absorption_spectroscopy-1.md
category: reference
title: Absorption spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Absorption_spectroscopy
date_saved: 2026-05-05T10:03:35.666525+00:00
instance: kb-cron
parent: absorption-spectroscopy-20260505-0
summary:
=== Relation to scattering and reflection spectra === The scattering and reflection spectra of a material are influenced by both its refractive index and its absorption spectrum. In an optical context, the absorption spectrum is typically quantified by the extinction coefficient, and the extinction and index coefficients are quantitatively related through the Kramers–Kronig relations. Therefore, the absorption spectrum can be derived from a scattering or reflection spectrum. This typically requires simplifying assumptions or models, and so the derived absorption spectrum is an approximation. == Applications == Absorption spectroscopy is useful in chemical analysis because of its specificity and its quantitative nature. The specificity of absorption spectra allows compounds to be distinguished from one another in a mixture, making absorption spectroscopy useful in wide variety of applications. For instance, Infrared gas analyzers can be used to detect pollutants in the air, distinguishing them from nitrogen, oxygen, water, and other expected constituents. The specificity also allows unknown samples to be identified by comparing a measured spectrum with a library of reference spectra. In many cases, qualitative information about a sample can be determined even if it is not in a library. Infrared spectra, for instance, have characteristic absorption bands that indicate if


id: absorption-spectroscopy-20260505-2
file: data/en.wikipedia.org/wiki/Absorption_spectroscopy-2.md
category: reference
title: Absorption spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Absorption_spectroscopy
date_saved: 2026-05-05T10:03:35.666525+00:00
instance: kb-cron
parent: absorption-spectroscopy-20260505-0
summary:
=== Basic approach === The most straightforward approach to absorption spectroscopy is to generate radiation with a source, measure a reference spectrum of that radiation with a detector and then re-measure the sample spectrum after placing the material of interest in between the source and detector. The two measured spectra can then be combined to determine the material's absorption spectrum. The sample spectrum alone is not sufficient to determine the absorption spectrum because it will be affected by the experimental conditions—the spectrum of the source, the absorption spectra of other materials between the source and detector, and the wavelength dependent characteristics of the detector. The reference spectrum will be affected in the same way, though, by these experimental conditions and therefore the combination yields the absorption spectrum of the material alone. A wide variety of radiation sources are employed in order to cover the electromagnetic spectrum. For spectroscopy, it is generally desirable for a source to cover a broad swath of wavelengths in order to measure a broad region of the absorption spectrum. Some sources inherently emit a broad spectrum. Examples of these include globars or other black body sources in the infrared, mercury lamps in the visible and ultraviolet,


id: acoustic-paramagnetic-resonance-20260505-0
file: data/en.wikipedia.org/wiki/Acoustic_paramagnetic_resonance-0.md
category: reference
title: Acoustic paramagnetic resonance
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Acoustic_paramagnetic_resonance
date_saved: 2026-05-05T10:03:36.866337+00:00
instance: kb-cron
parent: acoustic-paramagnetic-resonance-20260505-0
summary:
In acoustics, acoustic paramagnetic resonance (APR) is a phenomenon of resonant absorption of sound by a system of magnetic particles placed in an external magnetic field. It occurs when the energy of the sound wave quantum becomes equal to the splitting of the energy levels of the particles, the splitting being induced by the magnetic field. APR is a variation of electron paramagnetic resonance (EPR) where the acoustic rather than electromagnetic waves are absorbed by the studied sample. APR was theoretically predicted in 1952, independently by Semen Altshuler and Alfred Kastler, and was experimentally observed by W. G. Proctor and W. H. Tanttila in 1955. == History == After discovery of EPR in 1944, Evgeny Zavoisky predicted that the resonance phenomenon should not be restricted to radio or microwave absorption but could be extended to the sound waves. This idea was theoretically developed by his collaborator Semen Altshuler in 1952 and independently by Alfred Kastler; whereas Altshuler reported the effect on electron spins, Kastler calculated a nuclear spin system. The first experimental detection of the APR was reported in 1955 using 35Cl nuclei in single crystals of sodium chlorate. This nuclear-APR work was extended to electron-APR in 1959. Further applications


id: analytical-light-scattering-20260505-0
file: data/en.wikipedia.org/wiki/Analytical_light_scattering-0.md
category: reference
title: Analytical light scattering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Analytical_light_scattering
date_saved: 2026-05-05T10:03:38.039413+00:00
instance: kb-cron
parent: analytical-light-scattering-20260505-0
summary:
Analytical light scattering (ALS), also loosely referred to as SEC-MALS, is the implementation of static light scattering (SLS) and dynamic light scattering (DLS) techniques in an online or flow mode. A typical ALS instrument consists of an HPLC/FPLC chromatography system coupled in-line with appropriate light scattering and refractive index detectors. The advantage of ALS over conventional steady-state light scattering methods is that it allows separation of molecules/macromolecules on a chromatography column prior to analysis with light scattering detectors. Accordingly, ALS enables one to determine hydrodynamic properties of a single monodisperse species as opposed to bulk or average measurements on a sample afforded by conventional light scattering. == References ==


id: anisotropic-terahertz-microspectroscopy-20260505-0
file: data/en.wikipedia.org/wiki/Anisotropic_terahertz_microspectroscopy-0.md
category: reference
title: Anisotropic terahertz microspectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anisotropic_terahertz_microspectroscopy
date_saved: 2026-05-05T10:03:39.205651+00:00
instance: kb-cron
parent: anisotropic-terahertz-microspectroscopy-20260505-0
summary:
Anisotropic terahertz microspectroscopy (ATM) is a spectroscopic technique in which molecular vibrations in an anisotropic material are probed with short pulses of terahertz radiation whose electric field is linearly polarized parallel to the surface of the material. The technique has been demonstrated in studies involving single crystal sucrose, fructose, oxalic acid, and molecular protein crystals in which the spatial orientation of molecular vibrations are of interest. == Explanation == When the electric field of a propagating beam of light oscillates in a direction perpendicular to its direction of propagation, it is said to be a polarized transverse wave. Light with an electric field constrained to a particular angle in the transverse plane is said to be linearly polarized. When linearly polarized light is transmitted through an isotropic material — a material that exhibits the same physical properties in all spatial directions — the amount of light absorbed by the material is the same when measured for all angles of the polarized light. The resulting absorbance spectrum is featureless as a function of the polarization angle. A material said to be anisotropic exhibits different physical properties, like absorbance, refractive index, conductivity and so on, along different spatial directions. Thus, when a


id: anisotropic-terahertz-microspectroscopy-20260505-1
file: data/en.wikipedia.org/wiki/Anisotropic_terahertz_microspectroscopy-1.md
category: reference
title: Anisotropic terahertz microspectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anisotropic_terahertz_microspectroscopy
date_saved: 2026-05-05T10:03:39.205651+00:00
instance: kb-cron
parent: anisotropic-terahertz-microspectroscopy-20260505-0
summary:
==== Instrument Design ==== An ATM designed with a rotated sample is typically a far-field measurement configuration using a time-domain spectroscopy strategy. A high power infrared laser is typically used. Its beam is split by a beamsplitter into two optical paths: a probe beam and a THz generation beam. The THz generation beam typically receives the greater fraction of NIR power in order to maximize the power of the THz light commonly generated by a voltage-pulsed photoconductive antenna. The generated THz light is collected through a hyper-hemispherical silicon lens and passed to an off-axis parabolic mirror that collimates the THz beam for polarization by a THz polarizer that is often made of a simple wire-grid. The linearly polarized THz beam is then focused by a second off-axis parabolic mirror onto the sample. The THz beam transmitted through the sample is again collected by a third off-axis parabolic mirror, collimated onto a fourth parabolic mirror that then focuses the beam onto an electro-optic (EO) crystal whose birefringence is perturbed by the strength of the THz beam. The NIR probe beam is passed through the EO crystal to probe the induced degree of birefringence caused by the THz beam and passed to


id: anisotropic-terahertz-microspectroscopy-20260505-2
file: data/en.wikipedia.org/wiki/Anisotropic_terahertz_microspectroscopy-2.md
category: reference
title: Anisotropic terahertz microspectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anisotropic_terahertz_microspectroscopy
date_saved: 2026-05-05T10:03:39.205651+00:00
instance: kb-cron
parent: anisotropic-terahertz-microspectroscopy-20260505-0
summary:
===== THz Quarter Waveplate ===== One strategy to provide full 360° rotation of THz polarization of equal electric field magnitude at the sample is to generate a circular state of polarization, then select particular linear polarization states from the circularly polarized beam with a THz polarizer. A circular polarization state may be generated by a quarter waveplate, however, common optical waveplates are typically designed for visible, near- and mid-infrared regions of the electromagnetic spectrum. A quarter waveplate designed for use in the THz frequency range consists of a right-angle silicon prism together with metal-coated planar mirrors as input/output. In particular, the silicon prism acts analogously to a Fresnel rhomb with a single total internal reflection on the longer face of the prism and is a passive broadband component that permits a wide frequency sweep during measurements. == Advantages == A few advantages of ATM over other related microspectroscopy techniques include the orientation of the THz electric field at the sample and the ability to readily measure materials that are sensitive to environmental conditions like hydration, cryo-cooling, and evacuation. === THz polarization orientation at the sample === A key characteristic of ATM is the orientation of the polarized electric field of


id: anomalous-x-ray-scattering-20260505-0
file: data/en.wikipedia.org/wiki/Anomalous_X-ray_scattering-0.md
category: reference
title: Anomalous X-ray scattering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anomalous_X-ray_scattering
date_saved: 2026-05-05T10:03:40.354899+00:00
instance: kb-cron
parent: anomalous-x-ray-scattering-20260505-0
summary:
Anomalous X-ray scattering (AXRS or XRAS) is a non-destructive determination technique within X-ray diffraction that makes use of the anomalous dispersion that occurs when a wavelength is selected that is in the vicinity of an absorption edge of one of the constituent elements of the sample. It is used in materials research to study nanometer sized differences in structure. == Atomic scattering factors == In X-ray diffraction the scattering factor f for an atom is roughly proportional to the number of electrons that it possesses. However, for wavelengths that approximate those for which the atom strongly absorbs radiation the scattering factor undergoes a change due to anomalous dispersion. The dispersion not only affects the magnitude of the factor but also imparts a phase shift in the elastic collision of the photon. The scattering factor can therefore best be described as a complex number: f = fo + Δf' + iΔf" == Contrast variation == The anomalous aspects of X-ray scattering have become the focus of considerable interest in the scientific community because of the availability of synchrotron radiation. In contrast to desktop X-ray sources that only operate at certain fixed wavelengths, synchrotron radiation is generated by accelerating electrons and using


id: arterial-spin-labelling-20260505-0
file: data/en.wikipedia.org/wiki/Arterial_spin_labelling-0.md
category: reference
title: Arterial spin labelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Arterial_spin_labelling
date_saved: 2026-05-05T10:03:41.600359+00:00
instance: kb-cron
parent: arterial-spin-labelling-20260505-0
summary:
Arterial spin labeling (ASL), also known as arterial spin tagging, is a magnetic resonance imaging technique used to quantify cerebral blood perfusion by labelling blood water as it flows throughout the brain. ASL specifically refers to magnetic labeling of arterial blood below or in the imaging slab, without the need of gadolinium contrast. A number of ASL schemes are possible, the simplest being flow alternating inversion recovery (FAIR) which requires two acquisitions of identical parameters with the exception of the out-of-slice saturation; the difference in the two images is theoretically only from inflowing spins, and may be considered a 'perfusion map'. The ASL technique was developed by John S. Leigh Jr, John A. Detre, Donald S. Williams, and Alan P. Koretsky in 1992. == Physics == Arterial spin labeling utilizes the water molecules circulating with the brain, and using a radiofrequency pulse, tracks the blood water as it circulates throughout the brain. After a period of time in microseconds (enough to allow the blood to circulate through the brain), a 'label' image is captured. A 'control' image is also acquired before the labeling of the blood water. A subtraction technique gives a measurement of perfusion. In order to increase SNR,


id: arterial-spin-labelling-20260505-1
file: data/en.wikipedia.org/wiki/Arterial_spin_labelling-1.md
category: reference
title: Arterial spin labelling
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Arterial_spin_labelling
date_saved: 2026-05-05T10:03:41.600359+00:00
instance: kb-cron
parent: arterial-spin-labelling-20260505-0
summary:
== Analysis of ASL images == ASL maps can mainly be analyzed using the same tools to analyze fMRI and VBM. Many ASL-specific toolboxes have been developed to assist in ASL analysis, such as BASIL (Bayesian inference for arterial spin labelling MRI), part of the FSL neuroimaging package and also Ze Wang's ASL toolbox (using MATLAB) to assist in the subtraction and averaging of the tagged/control pairs. A visual quality check is often needed to make sure that the perfusion map is valid (such as correct registration, or correct segmentation of non-cerebral materials such as the dura mater). A whole brain/voxel-wise approach can be analyzed by registering the ASL map into MNI space for group comparisons. A region of interest approach can be analyzed by registering the ASL map into a selected cluster, or an atlas, like a standard (such as the Harvard-Oxford Cortical atlas) or an individual atlas developed by software like FreeSurfer. The recommended procedure of ASL registration for voxel-wise analysis is to register the perfusion map to a gray matter segmentation of each individual in a non-rigid procedure. Gray matter often requires more oxygenation and is the source of more brain activity compared to white matter. Therefore,


id: ash-chemistry-20260505-0
file: data/en.wikipedia.org/wiki/Ash_(chemistry)-0.md
category: reference
title: Ash (chemistry)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ash_(chemistry)
date_saved: 2026-05-05T10:03:42.741481+00:00
instance: kb-cron
parent: ash-chemistry-20260505-0
summary:
In analytical chemistry, ashing or ash content determination is the process of mineralization by complete combustion for preconcentration of trace substances prior to a chemical analysis, such as chromatography, or optical analysis, such as spectroscopy. == Overview == The ash content of a sample is a measure of the amount of inorganic noncombustible material it contains. The residues after a sample is completely burnt - in contrast to the ash remaining after incomplete combustion - typically consist of oxides of the inorganic elements present in the original sample. Ash is one of the components in the proximate analysis of biological materials, consisting mainly of salty, inorganic constituents. It includes metal salts which are important for processes requiring ions such as Na+ (sodium), K+ (potassium), and Ca2+ (calcium). It also includes trace minerals which are required for unique molecules, such as chlorophyll and hemoglobin. Procedures for ash content determination are similar to procedures for loss on ignition. Typically, the term ash is used for primarily organic material such as fuels and foodstuffs, while the term loss on ignition is used for primarily inorganic material such as rocks and combusted ash. A crucible can be used to determine the percentage of ash


id: atom-probe-20260505-0
file: data/en.wikipedia.org/wiki/Atom_probe-0.md
category: reference
title: Atom probe
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atom_probe
date_saved: 2026-05-05T10:03:43.942629+00:00
instance: kb-cron
parent: atom-probe-20260505-0
summary:
The atom probe was introduced at the 14th Field Emission Symposium in 1967 by Erwin Wilhelm Müller and J. A. Panitz. It combined a field ion microscope with a mass spectrometer having a single particle detection capability and, for the first time, an instrument could “... determine the nature of one single atom seen on a metal surface and selected from neighboring atoms at the discretion of the observer”. Atom probes are unlike conventional optical or electron microscopes, in that the magnification effect comes from the magnification provided by a highly curved electric field, rather than by the manipulation of radiation paths. The method is destructive in nature removing ions from a sample surface in order to image and identify them, generating magnifications sufficient to observe individual atoms as they are removed from the sample surface. Through coupling of this magnification method with time of flight mass spectrometry, ions evaporated by application of electric pulses can have their mass-to-charge ratio computed. Through successive evaporation of material, layers of atoms are removed from a specimen, allowing for probing not only of the surface, but also through the material itself. Computer methods are used to rebuild a three-dimensional view of the sample,


id: atom-probe-20260505-1
file: data/en.wikipedia.org/wiki/Atom_probe-1.md
category: reference
title: Atom probe
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atom_probe
date_saved: 2026-05-05T10:03:43.942629+00:00
instance: kb-cron
parent: atom-probe-20260505-0
summary:
=== Imaging Atom Probe === The Imaging Atom-Probe (IAP) was introduced in 1974 by J. A. Panitz. It incorporated the features of the 10-cm Atom-Probe yet “... departs completely from [previous] atom probe philosophy. Rather than attempt to determine the identity of a surface species producing a preselected ion-image spot, we wish to determine the complete crystallographic distribution of a surface species of preselected mass-to-charge ratio. Now suppose that instead of operating the [detector] continuously, it is turned on for a short time coincidentally with the arrival of a preselected species of interest by applying a gate pulse a time T after the evaporation pulse has reached the specimen. If the duration of the gate pulse is shorter than the travel time between adjacent species, only that surface species having the unique travel time T will be detected and its complete crystallographic distribution displayed.” It was patented in 1975 as the Field Desorption Spectrometer. The Imaging Atom-Probe moniker was coined by A. J. Waugh in 1978 and the instrument was described in detail by J. A. Panitz in the same year. === Atom Probe Tomography (APT) === Modern day atom probe tomography uses a position sensitive detector aka a FIM


id: atom-probe-20260505-2
file: data/en.wikipedia.org/wiki/Atom_probe-2.md
category: reference
title: Atom probe
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atom_probe
date_saved: 2026-05-05T10:03:43.942629+00:00
instance: kb-cron
parent: atom-probe-20260505-0
summary:
given a known flight distance. F, for the ion, and a known flight time, t, U = f t {\displaystyle U={\frac {f}{t}}} and thus one can substitute these values to obtain the mass-to-charge for the ion. m n = − 2 e V 1 ( t f ) 2 {\displaystyle {\frac {m}{n}}=-2eV_{1}\left({\frac {t}{f}}\right)^{2}} Thus for an ion which traverses a 1 m flight path, across a time of 2000 ns, given an initial accelerating voltage of 5000 V (V in Si units is kg.m^2.s^-3.A^-1) and noting that one amu is 1×10−27 kg, the mass-to-charge ratio (more correctly the mass-to-ionisation value ratio) becomes ~3.86 amu/charge. The number of electrons removed, and thus net positive charge on the ion is not known directly, but can be inferred from the histogram (spectrum) of observed ions. === Magnification === The magnification in an atom is due to the projection of ions radially away from the small, sharp tip. Subsequently, in the far-field, the ions will be greatly magnified. This magnification is sufficient to observe field variations due to individual atoms, thus allowing in field ion and field evaporation modes for the imaging of single atoms. The standard projection model for the atom probe is


id: atom-probe-20260505-3
file: data/en.wikipedia.org/wiki/Atom_probe-3.md
category: reference
title: Atom probe
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atom_probe
date_saved: 2026-05-05T10:03:43.942629+00:00
instance: kb-cron
parent: atom-probe-20260505-0
summary:
=== System layout === At a minimum, an atom probe will consist of several key pieces of equipment. A vacuum system for maintaining the low pressures (~10−8 to 10−10 Pa) required, typically a classic 3 chambered UHV design. A system for the manipulation of samples inside the vacuum, including sample viewing systems. A cooling system to reduce atomic motion, such as a helium refrigeration circuit - providing sample temperatures as low as 15K. A high voltage system to raise the sample standing voltage near the threshold for field evaporation. A high voltage pulsing system, use to create timed field evaporation events A counter electrode that can be a simple disk shape (like earlier generation atom probes), or a cone-shaped Local Electrode. The voltage pulse (negative) is typically applied to the counter electrode. A detection system for single energetic ions that includes XY position and TOF information. Optionally, an atom probe may also include laser-optical systems for laser beam targeting and pulsing, if using laser-evaporation methods. In-situ reaction systems, heaters, or plasma treatment may also be employed for some studies as well as a pure noble gas introduction for FIM. === Performance === Collectable ion volumes were previously limited to several


id: atomic-absorption-spectroscopy-20260505-0
file: data/en.wikipedia.org/wiki/Atomic_absorption_spectroscopy-0.md
category: reference
title: Atomic absorption spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy
date_saved: 2026-05-05T10:03:45.133964+00:00
instance: kb-cron
parent: atomic-absorption-spectroscopy-20260505-0
summary:
Atomic absorption spectroscopy (AAS) is an elemental analysis method for determining the concentration of metals in a given sample. The principle of AAS relies on the vaporization of metals within a sample when introduced to a flame. Every ground state metal absorbs light radiation (and excites) at a different wavelength. This uniqueness allows each metallic element to have its own absorption spectrum that corresponds to its identity. The total absorbed radiation at a specific wavelength by an element in the sample is proportional to the density of atoms of the element. The quantification of this relationship is used to determine the concentration of specific metals in the sample. == History == The modern form of AAS was largely developed during the 1950s by a team of Australian chemists led by Sir Alan Walsh at the Commonwealth Scientific and Industrial Research Organisation, Division of Chemical Physics, in Melbourne, Australia. Alan Walsh first described AAS in an article titled "The Application of Atomic Absorption Spectra to Chemical Analysis" published in 1955 by the journal Spectrachemica Acta. In this article, Walsh emphasizes the importance of establishing a new technique that can provide an absolute method that can produce reliable chemical standards, which was


id: atomic-absorption-spectroscopy-20260505-1
file: data/en.wikipedia.org/wiki/Atomic_absorption_spectroscopy-1.md
category: reference
title: Atomic absorption spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy
date_saved: 2026-05-05T10:03:45.133964+00:00
instance: kb-cron
parent: atomic-absorption-spectroscopy-20260505-0
summary:
==== Line Source AAS ==== In line source AAS (LS AAS), the high resolution that is required for the measurement of atomic absorption is provided by the narrow line emission of the radiation source. The monochromator has to resolve the analytical line from other radiation emitted by the lamp. This can usually be accomplished with a band pass between 0.2 and 2 nm, i.e., a medium-resolution monochromator. Another feature to make LS AAS element-specific is modulation of the primary radiation and the use of a selective amplifier that is tuned to the same modulation frequency, as already postulated by Alan Walsh. This way any (unmodulated) radiation emitted for example by the atomizer can be excluded, which is imperative for LS AAS. Simple monochromators of the Littrow or (better) the Czerny-Turner design are typically used for LS AAS. Photomultiplier tubes are the most frequently used detectors in LS AAS, although solid state detectors might be preferred because of their better signal-to-noise ratio. ==== Continuum Source AAS ==== When a continuum radiation source is used for AAS, a high-resolution monochromator is required. The resolution must be equal to or better than the half-width of an atomic absorption line (about 2 pm) in


id: atomic-absorption-spectroscopy-20260505-2
file: data/en.wikipedia.org/wiki/Atomic_absorption_spectroscopy-2.md
category: reference
title: Atomic absorption spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy
date_saved: 2026-05-05T10:03:45.133964+00:00
instance: kb-cron
parent: atomic-absorption-spectroscopy-20260505-0
summary:
Electrothermal AAS (ET AAS) using graphite tube atomizers was pioneered by Boris V. L'vov at the Saint Petersburg Polytechnical Institute, Russia, since the late 1950s, and investigated in parallel by Hans Massmann at the Institute of Spectrochemistry and Applied Spectroscopy (ISAS) in Dortmund, Germany. Although a wide variety of graphite tube designs have been used over the years, typical dimensions are 20–25 mm in length and 5–6 mm inner diameter. With this technique liquid/dissolved, solid, and gaseous samples may be analyzed directly. A measured volume (typically 10–50 μL) or a weighed mass (typically around 1 mg) of a solid sample is introduced into the graphite tube and subject to a temperature program. This typically consists of stages of drying – the solvent is evaporated; pyrolysis – the majority of the matrix constituents are removed; atomization – the analyte element is released to the gaseous phase; and cleaning – residues left in the graphite tube are removed at high temperature. The graphite tubes are heated via their ohmic resistance using a low-voltage high-current power supply; the temperature in the individual stages can be controlled very closely, and temperature ramps between the individual stages facilitate the separation of sample components. Tubes may


id: atomic-absorption-spectroscopy-20260505-3
file: data/en.wikipedia.org/wiki/Atomic_absorption_spectroscopy-3.md
category: reference
title: Atomic absorption spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy
date_saved: 2026-05-05T10:03:45.133964+00:00
instance: kb-cron
parent: atomic-absorption-spectroscopy-20260505-0
summary:
== Background absorption and background correction == The relatively small number of atomic absorption lines (compared to atomic emission lines) and their narrow width (a few pm) make spectral overlap rare; there are only few examples known that an absorption line from one element will overlap with another. Molecular absorption, in contrast, is much broader, so that it is more likely that some molecular absorption band will overlap with an atomic line. This kind of absorption might be caused by un-dissociated molecules of concomitant elements of the sample or by flame gases. We have to distinguish between the spectra of di-atomic molecules, which exhibit a pronounced fine structure, and those of larger (usually tri-atomic) molecules that don't show such fine structure. Another source of background absorption, particularly in ET AAS, is scattering of the primary radiation at particles that are generated in the atomization stage, when the matrix could not be removed sufficiently in the pyrolysis stage. All these phenomena, molecular absorption and radiation scattering, can result in artificially high absorption and an improperly high (erroneous) calculation for the concentration or mass of the analyte in the sample. There are several techniques available to correct for background absorption, and they


id: atomic-absorption-spectroscopy-20260505-4
file: data/en.wikipedia.org/wiki/Atomic_absorption_spectroscopy-4.md
category: reference
title: Atomic absorption spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy
date_saved: 2026-05-05T10:03:45.133964+00:00
instance: kb-cron
parent: atomic-absorption-spectroscopy-20260505-0
summary:
==== Background correction using a least-squares algorithm ==== The above technique can obviously not correct for a background with fine structure, as in this case the absorbance will be different at each of the correction pixels. In this case, HR-CS AAS is offering the possibility to measure correction spectra of the molecule(s) that is (are) responsible for the background and store them in the computer. These spectra are then multiplied with a factor to match the intensity of the sample spectrum and subtracted pixel by pixel and spectrum by spectrum from the sample spectrum using a least-squares algorithm. This might sound complex, but first of all the number of di-atomic molecules that can exist at the temperatures of the atomizers used in AAS is relatively small, and second, the correction is performed by the computer within a few seconds. The same algorithm can actually also be used to correct for direct line overlap of two atomic absorption lines, making HR-CS AAS the only AAS technique that can correct for this kind of spectral interference. == Applications == AAS is typically used to measure the concentration of metals in a wide variety of substances. For example, AAS has been used to


id: atomic-emission-spectroscopy-20260505-0
file: data/en.wikipedia.org/wiki/Atomic_emission_spectroscopy-0.md
category: reference
title: Atomic emission spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_emission_spectroscopy
date_saved: 2026-05-05T10:03:46.298080+00:00
instance: kb-cron
parent: atomic-emission-spectroscopy-20260505-0
summary:
Atomic emission spectroscopy (AES) is a method of chemical analysis that uses the intensity of light emitted from a flame, plasma, arc, or spark at a particular wavelength to determine the quantity of an element in a sample. The wavelength of the atomic spectral line in the emission spectrum gives the identity of the element while the intensity of the emitted light is proportional to the number of atoms of the element. The sample may be excited by various methods. Atomic Emission Spectroscopy allows us to measure interactions between electromagnetic radiation and physical atoms and molecules. This interaction is measured in the form of electromagnetic waves representing the changes in energy between atomic energy levels. When elements are burned by a flame, they emit electromagnetic radiation that can be recorded in the form of spectral lines. Each element has its own unique spectral line because each element has a different atomic arrangement, so this method is an important tool for identifying the makeup of materials. Robert Bunsen and Gustav Kirchhoff were the first to establish atomic emission spectroscopy as a tool in chemistry. When an element is burned in a flame, its atoms move from the ground electronic state to


id: atomic-force-microscopy-20260505-0
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-0.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. == Overview == Atomic force microscopy (AFM) gathers information by "feeling" or "touching" the surface with a mechanical probe. Piezoelectric elements that facilitate tiny but accurate and precise movements on (electronic) command enable precise scanning. Despite the name, the Atomic Force Microscope does not use the nuclear force. === Abilities and spatial resolution === The AFM has three major abilities: force measurement, topographic imaging, and manipulation. In force measurement, AFMs can be used to measure the forces between the probe and the sample as a function of their mutual separation. This can be applied to perform force spectroscopy, to measure the mechanical properties of the sample, such as the sample's Young's modulus, a measure of stiffness. For imaging, the reaction of the probe to the forces that the sample imposes on it can be used to form an image of the three-dimensional shape (topography) of a sample surface at a high resolution. This is achieved by raster scanning the position of


id: atomic-force-microscopy-20260505-1
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-1.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
==== Image formation ==== This section applies specifically to imaging in § Contact mode. For other imaging modes, the process is similar, except that "deflection" should be replaced by the appropriate feedback variable. When using the AFM to image a sample, the tip is brought into contact with the sample, and the sample is raster scanned along an x–y grid. Most commonly, an electronic feedback loop is employed to keep the probe-sample force constant during scanning. This feedback loop has the cantilever deflection as input, and its output controls the distance along the z axis between the probe support (2 in fig. 3) and the sample support (8 in fig 3). As long as the tip remains in contact with the sample, and the sample is scanned in the x–y plane, height variations in the sample will change the deflection of the cantilever. The feedback then adjusts the height of the probe support so that the deflection is restored to a user-defined value (the setpoint). A properly adjusted feedback loop adjusts the support-sample separation continuously during the scanning motion, such that the deflection remains approximately constant. In this situation, the feedback output equals the sample surface topography to within a


id: atomic-force-microscopy-20260505-2
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-2.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
=== Imaging modes === AFM operation is usually described as one of three modes, according to the nature of the tip motion: contact mode, also called static mode (as opposed to the other two modes, which are called dynamic modes); tapping mode, also called intermittent contact, AC mode, or vibrating mode, or, after the detection mechanism, amplitude modulation AFM; and non-contact mode, or, again after the detection mechanism, frequency modulation AFM. Despite the nomenclature, repulsive contact can occur or be avoided both in amplitude modulation AFM and frequency modulation AFM, depending on the settings. ==== Contact mode ==== In contact mode, the tip is "dragged" across the surface of the sample and the contours of the surface are measured either using the deflection of the cantilever directly or, more commonly, using the feedback signal required to keep the cantilever at a constant position. Because the measurement of a static signal is prone to noise and drift, low stiffness cantilevers (i.e. cantilevers with a low spring constant, k) are used to achieve a large enough deflection signal while keeping the interaction force low. Close to the surface of the sample, attractive forces can be quite strong, causing the tip to "snap-in"


id: atomic-force-microscopy-20260505-3
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-3.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
==== Non-contact mode ==== In non-contact atomic force microscopy mode, the tip of the cantilever does not contact the sample surface. The cantilever is instead oscillated at either its resonant frequency (frequency modulation) or just above (amplitude modulation) where the amplitude of oscillation is typically a few nanometers (<10 nm) down to a few picometers. The van der Waals forces, which are strongest from 1 nm to 10 nm above the surface, or any other long-range force that extends above the surface acts to decrease the resonance frequency of the cantilever. This decrease in resonant frequency combined with the feedback loop system maintains a constant oscillation amplitude or frequency by adjusting the average tip-to-sample distance. Measuring the tip-to-sample distance at each (x,y) data point allows the scanning software to construct a topographic image of the sample surface. Non-contact mode AFM does not suffer from tip or sample degradation effects that are sometimes observed after taking numerous scans with contact AFM. This makes non-contact AFM preferable to contact AFM for measuring soft samples, e.g. biological samples and organic thin film. In the case of rigid samples, contact and non-contact images may look the same. However, if a few monolayers of adsorbed


id: atomic-force-microscopy-20260505-4
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-4.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
=== Topographic image of FM-AFM === When the distance between the probe and the sample is brought to the range where atomic force may be detected, while a cantilever is excited in its natural eigenfrequency (f0), the resonance frequency f of the cantilever may shift from its original resonance frequency. In other words, in the range where atomic force may be detected, a frequency shift (df =f–f0) will also be observed. When the distance between the probe and the sample is in the non-contact region, the frequency shift increases in negative direction as the distance between the probe and the sample gets smaller. When the sample has concavity and convexity, the distance between the tip-apex and the sample varies in accordance with the concavity and convexity accompanied with a scan of the sample along x–y direction (without height regulation in z-direction). As a result, the frequency shift arises. The image in which the values of the frequency obtained by a raster scan along the x–y direction of the sample surface are plotted against the x–y coordination of each measurement point is called a constant-height image. On the other hand, the df may be kept constant by moving the probe upward


id: atomic-force-microscopy-20260505-5
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-5.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
== Probe == An AFM probe has a sharp tip on the free-swinging end of a cantilever that protrudes from a holder. The dimensions of the cantilever are in the scale of micrometers. The radius of the tip is usually on the scale of a few nanometers to a few tens of nanometers. (Specialized probes exist with much larger end radii, for example probes for indentation of soft materials.) The cantilever holder, also called the holder chip—often 1.6 mm by 3.4 mm in size—allows the operator to hold the AFM cantilever/probe assembly with tweezers and fit it into the corresponding holder clips on the scanning head of the atomic force microscope. This device is most commonly called an "AFM probe", but other names include "AFM tip" and "cantilever" (employing the name of a single part as the name of the whole device). An AFM probe is a particular type of SPM probe. AFM probes are manufactured with MEMS technology. Most AFM probes used are made from silicon (Si), but borosilicate glass and silicon nitride are also in use. AFM probes are considered consumables as they are often replaced when the tip apex becomes dull or contaminated or when the cantilever


id: atomic-force-microscopy-20260505-6
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-6.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
f m = − 2 π R γ L ( cos ⁡ θ + cos ⁡ ϕ ) ( 1 − d h d D ) {\displaystyle f_{m}=-2\pi R\gamma _{L}(\cos \theta +\cos \phi )\left(1-{\frac {dh}{dD}}\right)} for dry on wet, f m = − 2 π R γ L d r 0 d D {\displaystyle f_{m}=-2\pi R\gamma _{L}{\frac {dr_{0}}{dD}}} for wet on wet, where θ is the contact angle of the dry sphere and φ is the immersed angle, as shown in the figure For a conical tip, the formula becomes: f m = − 2 π R γ L tan ⁡ δ cos ⁡ δ ( cos ⁡ θ + sin ⁡ δ ) ( h D ) ( 1 − d h d D ) {\displaystyle f_{m}=-2\pi R\gamma _{L}{\frac {\tan \delta }{\cos \delta }}(\cos \theta +\sin \delta )(hD)\left(1-{\frac {dh}{dD}}\right)} for dry on wet f m = − 2 π R γ L ( 1 cos ⁡ δ + sin ⁡ δ ) ( r 0 ) ( d r 0 d D ) {\displaystyle f_{m}=-2\pi R\gamma _{L}\left({\frac {1}{\cos \delta }}+\sin \delta \right)(r_{0})\left({\frac {dr_{0}}{dD}}\right)} for wet on wet where δ is the half cone angle and r0 and h are


id: atomic-force-microscopy-20260505-7
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-7.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
== Piezoelectric scanners == AFM scanners are made from piezoelectric material, which expands and contracts proportionally to an applied voltage. Whether they elongate or contract depends upon the polarity of the voltage applied. Traditionally the tip or sample is mounted on a "tripod" of three piezo crystals, with each responsible for scanning in the x,y and z directions. In 1986, the same year as the AFM was invented, a new piezoelectric scanner, the tube scanner, was developed for use in STM. Later tube scanners were incorporated into AFMs. The tube scanner can move the sample in the x, y, and z directions using a single tube piezo with a single interior contact and four external contacts. An advantage of the tube scanner compared to the original tripod design, is better vibrational isolation, resulting from the higher resonant frequency of the single element construction, in combination with a low resonant frequency isolation stage. A disadvantage is that the x-y motion can cause unwanted z motion resulting in distortion. Another popular design for AFM scanners is the flexure stage, which uses separate piezos for each axis, and couples them through a flexure mechanism. Scanners are characterized by their sensitivity, which is the


id: atomic-force-microscopy-20260505-8
file: data/en.wikipedia.org/wiki/Atomic_force_microscopy-8.md
category: reference
title: Atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atomic_force_microscopy
date_saved: 2026-05-05T10:03:47.482245+00:00
instance: kb-cron
parent: atomic-force-microscopy-20260505-0
summary:
AFM images can also be affected by nonlinearity, hysteresis, and creep of the piezoelectric material and cross-talk between the x, y, z axes that may require software enhancement and filtering. Such filtering could "flatten" out real topographical features. However, newer AFMs utilize real-time correction software (for example, feature-oriented scanning) or closed-loop scanners, which practically eliminate these problems. Some AFMs also use separated orthogonal scanners (as opposed to a single tube), which also serve to eliminate part of the cross-talk problems. As with any other imaging technique, there is the possibility of image artifacts, which could be induced by an unsuitable tip, a poor operating environment, or even by the sample itself, as depicted on the right. These image artifacts are unavoidable; however, their occurrence and effect on results can be reduced through various methods. Artifacts resulting from a too-coarse tip can be caused for example by inappropriate handling or de facto collisions with the sample by either scanning too fast or having an unreasonably rough surface, causing actual wearing of the tip. Due to the nature of AFM probes, they cannot normally measure steep walls or overhangs. Specially made cantilevers and AFMs can be used to modulate the probe sideways


id: attenuated-total-reflectance-20260505-0
file: data/en.wikipedia.org/wiki/Attenuated_total_reflectance-0.md
category: reference
title: Attenuated total reflectance
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Attenuated_total_reflectance
date_saved: 2026-05-05T10:03:48.746520+00:00
instance: kb-cron
parent: attenuated-total-reflectance-20260505-0
summary:
Attenuated total reflection (ATR) is a sampling technique used in conjunction with infrared spectroscopy which enables samples to be examined directly in the solid or liquid state without further preparation. ATR uses a property of total internal reflection resulting in an evanescent wave. A beam of infrared light (IR) is passed through the ATR crystal in such a way that it reflects at least once off the internal surface in contact with the sample. This reflection forms the evanescent wave which extends into the sample. The penetration depth into the sample is typically between 0.5 and 2 micrometres, with the exact value determined by the wavelength of light, the angle of incidence and the indices of refraction for the ATR crystal and the medium being probed. The number of reflections may be varied by varying the angle of incidence. The beam is then collected by a detector as it exits the crystal. Most modern infrared spectrometers can be converted to characterise samples via ATR by mounting the ATR accessory in the spectrometer's sample compartment. The accessibility, rapid sample turnaround and ease of use of ATR with Fourier transform infrared spectroscopy (FTIR) has led to substantial use by the scientific community.


id: automated-mineralogy-20260505-0
file: data/en.wikipedia.org/wiki/Automated_mineralogy-0.md
category: reference
title: Automated mineralogy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Automated_mineralogy
date_saved: 2026-05-05T10:03:49.957984+00:00
instance: kb-cron
parent: automated-mineralogy-20260505-0
summary:
Automated mineralogy is a generic term describing a range of analytical solutions, areas of commercial enterprise, and a growing field of scientific research and engineering applications involving largely automated and quantitative analysis of minerals, rocks and man-made materials. == Technology == Automated mineralogy analytical solutions are characterised by integrating largely automated measurement techniques based on Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). Commercially available lab-based solutions include QEMSCAN and Mineral Liberation Analyzer (MLA) from FEI Company, Mineralogic from Zeiss, AZtecMineral from Oxford Instruments, the TIMA (Tescan integrated mineral analyzer) from TESCAN, AMICS from Bruker, and MaipSCAN from Rock Scientific. The first oil & gas wellsite solution was launched jointly by Zeiss and CGG Veritas in 2011 called RoqSCAN. This was followed approximately 6 months later by the release of QEMSCAN Wellsite by FEI Company. More recently in 2016, a ruggedized mine site solution for mining and mineral processing was launched by Zeiss called MinSCAN. == Business == The business of automated mineralogy is concerned with the commercialisation of the technology and software in terms of development and marketing of integrated solutions. This includes all aspects of: service; maintenance; customer support; R&D; marketing and sales. Customers of automated mineralogy


id: bet-theory-20260505-0
file: data/en.wikipedia.org/wiki/BET_theory-0.md
category: reference
title: BET theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/BET_theory
date_saved: 2026-05-05T10:03:51.162056+00:00
instance: kb-cron
parent: bet-theory-20260505-0
summary:
Brunauer–Emmett–Teller (BET) theory aims to explain the physical adsorption of gas molecules on a solid surface and serves as the basis for an important analysis technique for the measurement of the specific surface area of materials. The observations are very often referred to as physical adsorption or physisorption. In 1938, Stephen Brunauer, Paul Hugh Emmett, and Edward Teller presented their theory in the Journal of the American Chemical Society. BET theory applies to systems of multilayer adsorption that usually utilizes a probing gas (called the adsorbate) that does not react chemically with the adsorptive (the material upon which the gas attaches to) to quantify specific surface area. Nitrogen is the most commonly employed gaseous adsorbate for probing surface(s). For this reason, standard BET analysis is most often conducted at the boiling temperature of N2 (77 K). Other probing adsorbates are also utilized, albeit less often, allowing the measurement of surface area at different temperatures and measurement scales. These include argon, carbon dioxide, and water. Specific surface area is a scale-dependent property, with no single true value of specific surface area definable, and thus quantities of specific surface area determined through BET theory may depend on the adsorbate molecule utilized and


id: bet-theory-20260505-1
file: data/en.wikipedia.org/wiki/BET_theory-1.md
category: reference
title: BET theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/BET_theory
date_saved: 2026-05-05T10:03:51.162056+00:00
instance: kb-cron
parent: bet-theory-20260505-0
summary:
Adsorptions occur only on well-defined sites of the sample surface (one per molecule) The only molecular interaction considered is the following one: a molecule can act as a single adsorption site for a molecule of the upper layer. The uppermost molecule layer is in equilibrium with the gas phase, i.e. similar molecule adsorption and desorption rates. The desorption is a kinetically limited process, i.e. a heat of adsorption must be provided: these phenomena are homogeneous, i.e. same heat of adsorption for a given molecule layer. it is E1 for the first layer, i.e. the heat of adsorption at the solid sample surface the other layers are assumed similar and can be represented as condensed species, i.e. liquid state. Hence, the heat of adsorption is EL is equal to the heat of liquefaction. At the saturation pressure, the molecule layer number tends to infinity (i.e. equivalent to the sample being surrounded by a liquid phase) Consider a given amount of solid sample in a controlled atmosphere. Let θi be the fractional coverage of the sample surface covered by a number i of successive molecule layers. Let us assume that the adsorption rate Rads,i-1 for molecules on a layer (i-1) (i.e. formation


id: bet-theory-20260505-2
file: data/en.wikipedia.org/wiki/BET_theory-2.md
category: reference
title: BET theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/BET_theory
date_saved: 2026-05-05T10:03:51.162056+00:00
instance: kb-cron
parent: bet-theory-20260505-0
summary:
∑ n = 1 ∞ θ n = θ 0 + c θ 0 x ∑ n = 0 ∞ x n = θ 0 + c θ 0 x 1 − x , | x | < 1 {\displaystyle \sum _{n=1}^{\infty }\theta _{n}=\theta _{0}+c\theta _{0}x\sum _{n=0}^{\infty }x^{n}=\theta _{0}+c\theta _{0}{\frac {x}{1-x}},\quad |x|<1} Lastly, defining the excess coverage as V excess = V ads / V mono {\displaystyle V_{\text{excess}}=V_{\text{ads}}/V_{\text{mono}}} , the excess volume relative to the volume of an adsorbed mono-layer becomes V excess = ∑ n = 0 ∞ n θ n 1 = ∑ n = 0 ∞ n θ n ∑ n = 0 ∞ θ n = c x ( 1 − x ) ( 1 + ( c − 1 ) x ) {\displaystyle V_{\text{excess}}={\frac {\sum _{n=0}^{\infty }n\theta _{n}}{1}}={\frac {\sum _{n=0}^{\infty }n\theta _{n}}{\sum _{n=0}^{\infty }\theta _{n}}}={\frac {cx}{(1-x)(1+(c-1)x)}}} where the last equality was obtained by making use of the series expansions presented above. The constant c {\displaystyle c} must be interpreted as the relative binding affinity the substance A has towards a surface, relative to its own liquid. If c > 1 {\displaystyle c>1} then the initial part of the isotherm will be reminiscent of the Langmuir


id: bet-theory-20260505-3
file: data/en.wikipedia.org/wiki/BET_theory-3.md
category: reference
title: BET theory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/BET_theory
date_saved: 2026-05-05T10:03:51.162056+00:00
instance: kb-cron
parent: bet-theory-20260505-0
summary:
=== Catalysis === In the field of solid catalysis, the surface area of catalysts is an important factor in catalytic activity. Inorganic materials such as mesoporous silica and layered clay minerals have high surface areas of several hundred m2/g calculated by the BET method, indicating the possibility of application for efficient catalytic materials. === Specific surface area calculation === The ISO 9277 standard for calculating the specific surface area of solids is based on the BET method. The method has also been adapted for determination of specific area of ceramics and non-ferrous metal powders. === Thermal desorption === In 2023, researchers in the United States developed a method to determine BET surface areas using a thermogravimetric analyzer (TGA). This method uses a TGA to heat a porous sample loaded with an adsorbate, the produced plot of sample mass vs. temperature is then mapped into a standard isotherm to which BET theory is applied as normal. Common fluids, e.g. water or toluene, can be used as adsorbates for the TGA method allowing the specific interactions of different adsorbates to be determined, as these frequently differ from the commonly used nitrogen. == See also == Adsorption Capillary condensation Langmuir adsorption model Mercury


id: bimodal-atomic-force-microscopy-20260505-0
file: data/en.wikipedia.org/wiki/Bimodal_atomic_force_microscopy-0.md
category: reference
title: Bimodal atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bimodal_atomic_force_microscopy
date_saved: 2026-05-05T10:03:52.382038+00:00
instance: kb-cron
parent: bimodal-atomic-force-microscopy-20260505-0
summary:
Bimodal Atomic Force Microscopy (bimodal AFM) is an advanced atomic force microscopy technique characterized by generating high-spatial resolution maps of material properties. Topography, deformation, elastic modulus, viscosity coefficient or magnetic field maps might be generated. Bimodal AFM is based on the simultaneous excitation and detection of two eigenmodes (resonances) of a force microscope microcantilever. == History == Numerical and theoretical considerations prompted the development of bimodal AFM. The method was initially thought to enhance topographic contrast in air environments. Three subsequent advances such as the capability to detect non-topography properties such electrostatic and magnetic interactions; imaging in liquid and ultra-high vacuum and its genuine quantitative features set the stage for further developments and applications. == Principles of Bimodal AFM == The interaction of the tip with the sample modifies the amplitudes, phase shifts and frequency resonances of the excited modes. Those changes are detected and processed by the feedback of the instrument. Several features make bimodal AFM a very powerful surface characterization method at the nanoscale. (i) Resolution. Atomic, molecular or nanoscale spatial resolution was demonstrated. (ii) Simultaneity. Maps of different properties are generated at the same time. (iii) Efficiency. A maximum number of four data points per pixel are


id: bimodal-atomic-force-microscopy-20260505-1
file: data/en.wikipedia.org/wiki/Bimodal_atomic_force_microscopy-1.md
category: reference
title: Bimodal atomic force microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bimodal_atomic_force_microscopy
date_saved: 2026-05-05T10:03:52.382038+00:00
instance: kb-cron
parent: bimodal-atomic-force-microscopy-20260505-0
summary:
where T = T 1 T 2 {\displaystyle T=T_{1}T_{2}} is a time where the oscillation of both modes are periodic; Q i {\displaystyle Q_{i}} the quality factor of mode i. Bimodal AFM operation might be involve any pair of eigenmodes. However, experiments are commonly performed by exciting the first two eigenmodes. The theory of bimodal AFM provides analytical expressions to link material properties with microscope observables. For example, for a paraboloid probe (radius R {\displaystyle R} ) and a tip-sample force given by the linear viscoelastic Kelvin-Voigt model, the effective elastic modulus E e f f {\displaystyle E_{eff}} of the sample, viscous coefficient of compressibility η c o m {\displaystyle \eta _{com}} , loss tangent tan ⁡ ρ {\displaystyle \tan \rho } or retardation time τ {\displaystyle \tau } are expressed by E e f f = 4 2 Q 1 R k 2 2 k 1 Δ f 2 2 f 02 2 A 1 3 / 2 A 01 2 − A 1 2 {\displaystyle E_{eff}=4{\sqrt {2}}{\frac {Q_{1}}{\sqrt {R}}}{\frac {k_{2}^{2}}{k_{1}}}{\frac {\Delta f_{2}^{2}}{f_{02}^{2}}}{\frac {A_{1}^{3/2}}{A_{01}^{2}-A_{1}^{2}}}\,} η c o m = E e f f ω 1 [ A 01 sin ⁡ ϕ 1 − A 1 A 01 cos ⁡


id: cathodoluminescence-20260505-0
file: data/en.wikipedia.org/wiki/Cathodoluminescence-0.md
category: reference
title: Cathodoluminescence
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cathodoluminescence
date_saved: 2026-05-05T10:03:53.622728+00:00
instance: kb-cron
parent: cathodoluminescence-20260505-0
summary:
Cathodoluminescence is an optical and electromagnetic phenomenon in which electrons impacting on a luminescent material such as a phosphor, cause the emission of photons which may have wavelengths in the visible spectrum. A familiar example is the generation of light by an electron beam scanning the phosphor-coated inner surface of the screen of a television that uses a cathode-ray tube. Cathodoluminescence is the inverse of the photoelectric effect, in which electron emission is induced by irradiation with photons. == Origin == Luminescence in a semiconductor results when an electron in the conduction band recombines with a hole in the valence band. The difference energy (band gap) of this transition can be emitted in form of a photon. The energy (color) of the photon, and the probability that a photon and not a phonon will be emitted, depends on the material, its purity, and the presence of defects. First, the electron has to be excited from the valence band into the conduction band. In cathodoluminescence, this occurs as the result of an impinging high energy electron beam onto a semiconductor. However, these primary electrons carry far too much energy to directly excite electrons. Instead, the inelastic scattering of the primary electrons


id: cathodoluminescence-20260505-1
file: data/en.wikipedia.org/wiki/Cathodoluminescence-1.md
category: reference
title: Cathodoluminescence
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cathodoluminescence
date_saved: 2026-05-05T10:03:53.622728+00:00
instance: kb-cron
parent: cathodoluminescence-20260505-0
summary:
In scanning electron microscopes a focused beam of electrons impinges on a sample and induces it to emit light that is collected by an optical system, such as an elliptical mirror. From there, a fiber optic will transfer the light out of the microscope where it is separated into its component wavelengths by a monochromator and is then detected with a photomultiplier tube. By scanning the microscope's beam in an X-Y pattern and measuring the light emitted with the beam at each point, a map of the optical activity of the specimen can be obtained (cathodoluminescence imaging). Instead, by measuring the wavelength dependence for a fixed point or a certain area, the spectral characteristics can be recorded (cathodoluminescence spectroscopy). Furthermore, if the photomultiplier tube is replaced with a CCD camera, an entire spectrum can be measured at each point of a map (hyperspectral imaging). Moreover, the optical properties of an object can be correlated to structural properties observed with the electron microscope. The primary advantages to the electron microscope based technique is its spatial resolution. In a scanning electron microscope, the attainable resolution is on the order of a few ten nanometers, while in a (scanning) transmission electron microscope (TEM),


id: cell-unroofing-20260505-0
file: data/en.wikipedia.org/wiki/Cell_unroofing-0.md
category: reference
title: Cell unroofing
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cell_unroofing
date_saved: 2026-05-05T10:03:54.816547+00:00
instance: kb-cron
parent: cell-unroofing-20260505-0
summary:
Cell unroofing encompasses various methods used to isolate and expose the cell membrane of cells. Unlike the more common membrane extraction protocols performed with multiple steps of centrifugation (which aims to separate the membrane fraction from a cell lysate), cell unroofing aims to tear and preserve patches of the plasma membrane to perform in situ experiments using microscopy and biomedical spectroscopy. == History == The first observation of the bi-layer cell membrane was made in 1959 on a cell section using the electron microscope. However, the first micrograph of the internal side of a cell dates back to 1977 by M.V. Nermut. Professor John Heuser made substantial contributions in the field, imaging the detailed internal structure of the membrane and the cytoskeleton bound to it with extensive use of the electron microscope. It was only after the development of atomic force microscope operated in liquid that it became possible to image cell membranes in almost-physiological conditions and to test their mechanical properties. == Methods == Freeze-fracturing of monolayers Quick-freeze deep-etch electron microscopy and cryofixation Sonication for atomic force microscopy Single-cell unroofing == See also == Sonoporation Lysis == References ==


id: charge-modulation-spectroscopy-20260505-0
file: data/en.wikipedia.org/wiki/Charge_modulation_spectroscopy-0.md
category: reference
title: Charge modulation spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Charge_modulation_spectroscopy
date_saved: 2026-05-05T10:03:56.033551+00:00
instance: kb-cron
parent: charge-modulation-spectroscopy-20260505-0
summary:
Charge modulation spectroscopy is an electro-optical spectroscopy technique tool. It is used to study the charge carrier behavior of organic field-effect transistors. It measures the charge introduced optical transmission variation by directly probing the accumulation charge at the burning interface of semiconductor and dielectric layer where the conduction channel forms. == Principles == Unlike ultraviolet–visible spectroscopy which measures absorbance, charge modulation spectroscopy measures the charge introduced optical transmission variation. In other words, it reveals the new features in optical transmission introduced by charges. In this setup, there are mainly four components: lamp, monochromator, photodetector and lock-in amplifier. Lamp and monochromator are used for generating and selecting the wavelength. The selected wavelength passes through the transistor, and the transmitted light is recorded by the Photodiode. When the signal to noise ratio is very low, the signal can be modulated and recovered with a Lock-in amplifier. In the experiment, a direct current plus an alternating current bias are applied to the organic field-effect transistor. Charge carriers accumulate at the interface between the dielectric and the semiconductor (usually a few nanometers). With the appearance of the accumulation charge, the intensity of the transmitted light changes. The variation of the light intensity (§ Bleaching


id: chemical-ionization-20260505-0
file: data/en.wikipedia.org/wiki/Chemical_ionization-0.md
category: reference
title: Chemical ionization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_ionization
date_saved: 2026-05-05T10:03:57.240704+00:00
instance: kb-cron
parent: chemical-ionization-20260505-0
summary:
Chemical ionization (CI) is a soft ionization technique used in mass spectrometry. This was first introduced by Burnaby Munson and Frank H. Field in 1966. This technique is a branch of gaseous ion-molecule chemistry. Reagent gas molecules (often methane or ammonia) are ionized by electron ionization to form reagent ions, which subsequently react with analyte molecules in the gas phase to create analyte ions for analysis by mass spectrometry. Negative chemical ionization (NCI), charge-exchange chemical ionization, atmospheric-pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) are some of the common variants of the technique. CI mass spectrometry finds general application in the identification, structure elucidation and quantitation of organic compounds as well as some utility in biochemical analysis. Samples to be analyzed must be in vapour form, or else (in the case of liquids or solids), must be vapourized before introduction into the source. == Principles of operation == The chemical ionization process generally imparts less energy to an analyte molecule than does electron impact (EI) ionization, resulting in less fragmentation and usually a simpler spectrum. The amount of fragmentation, and therefore the amount of structural information produced by the process can be controlled to some degree by selection of


id: chemical-ionization-20260505-1
file: data/en.wikipedia.org/wiki/Chemical_ionization-1.md
category: reference
title: Chemical ionization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_ionization
date_saved: 2026-05-05T10:03:57.240704+00:00
instance: kb-cron
parent: chemical-ionization-20260505-0
summary:
== Advantages and limitations == One of the main advantages of CI over EI is the reduced fragmentation as noted above, which for more fragile molecules, results in a peak in the mass spectrum indicative of the molecular weight of the analyte. This proves to be a particular advantage for biological applications where EI often does not yield useful molecular ions in the spectrum. The spectra given by CI are simpler than EI spectra and CI can be more sensitive than other ionization methods, at least in part to the reduced fragmentation which concentrates the ion signal in fewer and therefore more intense peaks. The extent of fragmentation can be somewhat controlled by proper selection of reagent gases. Moreover, CI is often coupled to chromatographic separation techniques, thereby improving its usefulness in identification of compounds. As with EI, the method is limited to compounds that can be vapourized in the ion source. The lower degree of fragmentation can be a disadvantage in that less structural information is provided. Additionally, the degree of fragmentation and therefore the mass spectrum, can be sensitive to source conditions such as pressure, temperature, and the presence of impurities (such as water vapour) in the source.


id: chemical-shift-index-20260505-0
file: data/en.wikipedia.org/wiki/Chemical_shift_index-0.md
category: reference
title: Chemical shift index
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemical_shift_index
date_saved: 2026-05-05T10:03:58.435699+00:00
instance: kb-cron
parent: chemical-shift-index-20260505-0
summary:
The chemical shift index or CSI is a widely employed technique in protein nuclear magnetic resonance spectroscopy that can be used to display and identify the location (i.e. start and end) as well as the type of protein secondary structure (beta strands, helices and random coil regions) found in proteins using only backbone chemical shift data The technique was invented by David S. Wishart in 1992 for analyzing 1Hα chemical shifts and then later extended by him in 1994 to incorporate 13C backbone shifts. The original CSI method makes use of the fact that 1Hα chemical shifts of amino acid residues in helices tends to be shifted upfield (i.e. towards the right side of an NMR spectrum) relative to their random coil values and downfield (i.e. towards the left side of an NMR spectrum) in beta strands. Similar kinds of upfield and downfield trends are also detectable in backbone 13C chemical shifts. == Implementation == The CSI is a graph-based technique that essentially employs an amino acid-specific digital filter to convert every assigned backbone chemical shift value into a simple three-state (-1, 0, +1) index. This approach generates a more easily understood and much more visually pleasing graph of protein


id: coherent-diffraction-imaging-20260505-0
file: data/en.wikipedia.org/wiki/Coherent_diffraction_imaging-0.md
category: reference
title: Coherent diffraction imaging
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coherent_diffraction_imaging
date_saved: 2026-05-05T10:03:59.662514+00:00
instance: kb-cron
parent: coherent-diffraction-imaging-20260505-0
summary:
Coherent diffractive imaging (CDI) is a computational microscopy method that reconstructs images from coherent diffraction patterns without the use of lenses. It was first experimentally demonstrated in 1999 by Miao and collaborators using synchrotron X-rays and iterative phase retrieval. CDI has been applied to image structures such as nanotubes, nanocrystals, porous nanocrystalline layers, defects, potentially proteins, and more. In CDI, a highly coherent beam of X-rays, electrons or other wavelike particle or photon is incident on an object. The beam scattered by the object produces a diffraction pattern downstream which is then collected by a detector. This recorded pattern is then used to reconstruct an image via an iterative feedback algorithm. Effectively, the objective lens in a typical microscope is replaced with software to convert from the reciprocal space diffraction pattern into a real space image. The advantage in using no lenses is that the final image is aberration–free and so resolution is only diffraction and dose limited (dependent on wavelength, aperture size and exposure). Applying a simple inverse Fourier transform to information with only intensities is insufficient for creating an image from the diffraction pattern due to the missing phase information. This is called the phase problem. == Imaging


id: coherent-diffraction-imaging-20260505-1
file: data/en.wikipedia.org/wiki/Coherent_diffraction_imaging-1.md
category: reference
title: Coherent diffraction imaging
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coherent_diffraction_imaging
date_saved: 2026-05-05T10:03:59.662514+00:00
instance: kb-cron
parent: coherent-diffraction-imaging-20260505-0
summary:
== Reconstruction == In a typical reconstruction the first step is to generate random phases and combine them with the amplitude information from the reciprocal space pattern. Then a Fourier transform is applied back and forth to move between real space and reciprocal space with the modulus squared of the diffracted wave field set equal to the measured diffraction intensities in each cycle. By applying various constraints in real and reciprocal space the pattern evolves into an image after enough iterations of the HIO process. To ensure reproducibility the process is typically repeated with new sets of random phases with each run having typically hundreds to thousands of cycles. The constraints imposed in real and reciprocal space typically depend on the experimental setup and the sample to be imaged. The real space constraint is to restrict the imaged object to a confined region called the "support". For example, the object to be imaged can be initially assumed to reside in a region no larger than roughly the beam size. In some cases this constraint may be more restrictive, such as in a periodic support region for a uniformly spaced array of quantum dots. Other researchers have investigated imaging extended objects,


id: coherent-diffraction-imaging-20260505-2
file: data/en.wikipedia.org/wiki/Coherent_diffraction_imaging-2.md
category: reference
title: Coherent diffraction imaging
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coherent_diffraction_imaging
date_saved: 2026-05-05T10:03:59.662514+00:00
instance: kb-cron
parent: coherent-diffraction-imaging-20260505-0
summary:
Two wave sources are coherent when their frequency and waveforms are identical; this property of waves allows for stationary interference in which the wave is temporally or spatially constant and the waves are either added or subtracted from one another. Coherence is important in the context of CDI as the coherence of the two sources allows for the continuous emission of waves to occur. A constant phase difference and the coherence of a wave are necessary in order to obtain any type of interference pattern. Clearly a highly coherent beam of waves is required for CDI to work since the technique requires interference of diffracted waves. Coherent waves must be generated at the source (synchrotron, field emitter, etc.) and must maintain coherence until diffraction. It has been shown that the coherence width of the incident beam needs to be approximately twice the lateral width of the object to be imaged. However determining the size of the coherent patch to decide whether the object does or does not meet the criterion is subject to debate. As the coherence width is decreased, the size of the Bragg peaks in reciprocal space grows and they begin to overlap leading to decreased image resolution.


id: coherent-diffraction-imaging-20260505-3
file: data/en.wikipedia.org/wiki/Coherent_diffraction_imaging-3.md
category: reference
title: Coherent diffraction imaging
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coherent_diffraction_imaging
date_saved: 2026-05-05T10:03:59.662514+00:00
instance: kb-cron
parent: coherent-diffraction-imaging-20260505-0
summary:
== In situ CDI == Incomplete measurements have been a problem observed across all algorithms in CDI. Since the detector is too sensitive to absorb a particle beam directly, a beamstop or hole must be placed at its center to prevent direct contact (Pham 2020). Furthermore, detectors are often constructed with multiple panels with gaps between them where data again cannot be collected (Pham 2020). Ultimately, these qualities of the detector result in missing data within the diffraction patterns. In situ CDI is a new method of this imaging technology that could increase resistance to incomplete measurements. In situ CDI images a static region and a dynamic region that changes over time as a result of external stimuli (Hung Lo 2018). A series of diffraction patterns are collected over time with interference from the static and dynamic regions (Hung Lo 2018). Because of this interference, the static region acts as a time invariant constraint that phases patterns together in fewer iterations (Hung Lo 2018). Enforcing this static region as a constraint makes in situ CDI more robust to incomplete data and noise interference in the diffraction patterns (Hung Lo 2018). Overall, in situ CDI provides clearer data collection in fewer


id: collision-induced-dissociation-20260505-0
file: data/en.wikipedia.org/wiki/Collision-induced_dissociation-0.md
category: reference
title: Collision-induced dissociation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Collision-induced_dissociation
date_saved: 2026-05-05T10:04:00.852527+00:00
instance: kb-cron
parent: collision-induced-dissociation-20260505-0
summary:
Collision-induced dissociation (CID), also known as collisionally activated dissociation (CAD), is a mass spectrometry technique to induce fragmentation of selected ions in the gas phase. The selected ions (typically molecular ions or protonated molecules) are usually accelerated by applying an electrical potential to increase the ion kinetic energy and then allowed to collide with neutral molecules (often helium, nitrogen, or argon). In the collision, some of the kinetic energy is converted into internal energy which results in bond breakage and the fragmentation of the molecular ion into smaller fragments. These fragment ions can then be analyzed by tandem mass spectrometry. CID and the fragment ions produced by CID are used for several purposes. Partial or complete structural determination can be achieved. In some cases, identity can be established based on previous knowledge without determining structure. Another use is in simply achieving more sensitive and specific detection. By detecting a unique fragment ion, the precursor ion can be detected in the presence of other ions of the same m/z value (mass-to-charge ratio), reducing the background and increasing the limit of detection. == Low-energy CID and high-energy CID == Low-energy CID is typically carried out with ion kinetic energies less than approximately


id: combustion-analysis-20260505-0
file: data/en.wikipedia.org/wiki/Combustion_analysis-0.md
category: reference
title: Combustion analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Combustion_analysis
date_saved: 2026-05-05T10:04:02.028558+00:00
instance: kb-cron
parent: combustion-analysis-20260505-0
summary:
Combustion analysis is a method used in both organic chemistry and analytical chemistry to determine the elemental composition (more precisely empirical formula) of a pure organic compound by combusting the sample under conditions where the resulting combustion products can be quantitatively analyzed. Once the number of moles of each combustion product has been determined the empirical formula or a partial empirical formula of the original compound can be calculated. Applications for combustion analysis involve only the elements of carbon (C), hydrogen (H), nitrogen (N), and sulfur (S) as combustion of materials containing them convert these elements to their oxidized form (CO2, H2O, NO or NO2, and SO2) under high temperature high oxygen conditions. Notable interests for these elements involve measuring total nitrogen in food or feed to determine protein percentage, measuring sulfur in petroleum products, or measuring total organic carbon (TOC) in water. == History == The method was invented by Joseph Louis Gay-Lussac. Justus von Liebig studied the method while working with Gay-Lussac between 1822 and 1824 and improved the method in the following years to a level that it could be used as standard procedure for organic analysis. == Combustion train == A combustion train is an analytical


id: confocal-microscopy-20260505-0
file: data/en.wikipedia.org/wiki/Confocal_microscopy-0.md
category: reference
title: Confocal microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Confocal_microscopy
date_saved: 2026-05-05T10:04:03.194579+00:00
instance: kb-cron
parent: confocal-microscopy-20260505-0
summary:
Confocal microscopy, most frequently confocal laser scanning microscopy (CLSM) or laser scanning confocal microscopy (LSCM), is an optical imaging technique for increasing optical resolution and contrast of a micrograph by means of using a spatial pinhole to block out-of-focus light in image formation. Capturing multiple two-dimensional images at different depths in a sample enables the reconstruction of three-dimensional structures (a process known as optical sectioning) within an object. This technique is used extensively in the scientific and industrial communities and typical applications are in life sciences, semiconductor inspection and materials science. Light travels through the sample under a conventional microscope as far into the specimen as it can penetrate, while a confocal microscope only focuses a smaller beam of light at one narrow depth level at a time. The CLSM achieves a controlled and highly limited depth of field. == Basic concept == The principle of confocal imaging was patented in 1957 by Marvin Minsky and aims to overcome some limitations of traditional wide-field fluorescence microscopes. In a conventional (i.e., wide-field) fluorescence microscope, the entire specimen is flooded evenly in light from a light source. All parts of the sample can be excited at the same time and the resulting


id: confocal-microscopy-20260505-1
file: data/en.wikipedia.org/wiki/Confocal_microscopy-1.md
category: reference
title: Confocal microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Confocal_microscopy
date_saved: 2026-05-05T10:04:03.194579+00:00
instance: kb-cron
parent: confocal-microscopy-20260505-0
summary:
Four types of confocal microscopes are commercially available: Confocal laser scanning microscopes use multiple mirrors (typically 2 or 3 scanning linearly along the x- and the y- axes) to scan the laser across the sample and "descan" the image across a fixed pinhole and detector. This process is usually slow and does not work for live imaging, but can be useful to create high-resolution representative images of fixed samples. Spinning-disk (Nipkow disk) confocal microscopes use a series of moving pinholes on a disc to scan spots of light. Since a series of pinholes scans an area in parallel, each pinhole is allowed to hover over a specific area for a longer amount of time thereby reducing the excitation energy needed to illuminate a sample when compared to laser scanning microscopes. Decreased excitation energy reduces phototoxicity and photobleaching of a sample often making it the preferred system for imaging live cells or organisms. Microlens enhanced or dual spinning-disk confocal microscopes work under the same principles as spinning-disk confocal microscopes except a second spinning-disk containing micro-lenses is placed before the spinning-disk containing the pinholes. Every pinhole has an associated microlens. The micro-lenses act to capture a broad band of light and focus


id: confocal-microscopy-20260505-2
file: data/en.wikipedia.org/wiki/Confocal_microscopy-2.md
category: reference
title: Confocal microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Confocal_microscopy
date_saved: 2026-05-05T10:04:03.194579+00:00
instance: kb-cron
parent: confocal-microscopy-20260505-0
summary:
== Uses == CLSM is widely used in various biological science disciplines, from cell biology and genetics to microbiology and developmental biology. It is also used in quantum optics and nano-crystal imaging and spectroscopy. === Biology and medicine === Clinically, CLSM is used in the evaluation of various eye diseases, and is particularly useful for imaging, qualitative analysis, and quantification of endothelial cells of the cornea. It is used for localizing and identifying the presence of filamentary fungal elements in the corneal stroma in cases of keratomycosis, enabling rapid diagnosis and thereby early institution of definitive therapy. Research into CLSM techniques for endoscopic procedures (endomicroscopy) is also showing promise. In the pharmaceutical industry, it was recommended to follow the manufacturing process of thin film pharmaceutical forms, to control the quality and uniformity of the drug distribution. Confocal microscopy is also used to study biofilms — complex porous structures that are the preferred habitat of microorganisms. Some of temporal and spatial function of biofilms can be understood only by studying their structure on micro- and meso-scales. The study of microscale is needed to detect the activity and organization of single microorganisms. === Optics and crystallography === CLSM is used as the


id: confocal-microscopy-20260505-3
file: data/en.wikipedia.org/wiki/Confocal_microscopy-3.md
category: reference
title: Confocal microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Confocal_microscopy
date_saved: 2026-05-05T10:04:03.194579+00:00
instance: kb-cron
parent: confocal-microscopy-20260505-0
summary:
=== 1969: The first confocal laser scanning microscope === In 1969 and 1971, M. David Egger and Paul Davidovits from Yale University, published two papers describing the first confocal laser scanning microscope. It was a point scanner, meaning just one illumination spot was generated. It used epi-Illumination-reflection microscopy for the observation of nerve tissue. A 5 mW Helium-Neon-Laser with 633 nm light was reflected by a semi-transparent mirror towards the objective. The objective was a simple lens with a focal length of 8.5 mm. As opposed to all earlier and most later systems, the sample was scanned by movement of this lens (objective scanning), leading to a movement of the focal point. Reflected light came back to the semitransparent mirror, the transmitted part was focused by another lens on the detection pinhole behind which a photomultiplier tube was placed. The signal was visualized by a CRT of an oscilloscope, the cathode ray was moved simultaneously with the objective. A special device allowed to make Polaroid photos, three of which were shown in the 1971 publication. The authors speculate about fluorescent dyes for in vivo investigations. They cite Minsky's patent, thank Steve Baer, at the time a doctoral student at the


id: crucible-20260505-0
file: data/en.wikipedia.org/wiki/Crucible-0.md
category: reference
title: Crucible
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Crucible
date_saved: 2026-05-05T10:04:04.364838+00:00
instance: kb-cron
parent: crucible-20260505-0
summary:
A crucible is a container in which metals or other substances may be melted or subjected to very high temperatures. Although crucibles have historically tended to be made out of clay, they can be made from any material that withstands temperatures high enough to melt or otherwise alter its contents. == History == === Typology and chronology === The form of the crucible has varied through time, with designs reflecting the process for which they are used, as well as regional variation. The earliest crucible forms derive from the sixth/fifth millennium B.C. in Eastern Europe and Iran. === Chalcolithic === Crucibles used for copper smelting were generally wide shallow vessels made from clay that lacks refractory properties which is similar to the types of clay used in other ceramics of the time. During the Chalcolithic period, crucibles were heated from the top by using blowpipes. Ceramic crucibles from this time had slight modifications to their designs such as handles, knobs or pouring spouts allowing them to be more easily handled and poured. Early examples of this practice can be seen in Feinan, Jordan. These crucibles have added handles to allow for better manipulation, however, due to the poor preservation of


id: crucible-20260505-1
file: data/en.wikipedia.org/wiki/Crucible-1.md
category: reference
title: Crucible
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Crucible
date_saved: 2026-05-05T10:04:04.364838+00:00
instance: kb-cron
parent: crucible-20260505-0
summary:
=== Medieval period === Smelting and melting of copper and its alloys such as leaded bronze was done in crucibles similar to those of the Roman period which have thinner walls and flat bases to sit within the furnaces. The technology for this type of smelting started to change at the end of the medieval period with the introduction of new tempering material for the ceramic crucibles. Some of these copper alloy crucibles were used in the making of bells. Bell foundry crucibles had to be larger at about 60 cm. These later medieval crucibles were a more mass-produced product. The cementation process, which was lost from the end of the Roman to the early medieval period, continued in the same way with brass. Brass production increased during the medieval period due to a better understanding of the technology behind it. Furthermore, the process for carrying out cementation for brass did not change greatly until the 19th century. However, during this period a vast and highly important technological innovation happened using the cementation process, the production of crucible steel. Steel production using iron and carbon works similarly to brass, with the iron metal being mixed with carbon to produce steel.


id: crucible-20260505-2
file: data/en.wikipedia.org/wiki/Crucible-2.md
category: reference
title: Crucible
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Crucible
date_saved: 2026-05-05T10:04:04.364838+00:00
instance: kb-cron
parent: crucible-20260505-0
summary:
In the area of chemical analysis, crucibles are used in quantitative gravimetric chemical analysis (analysis by measuring mass of an analyte or its derivative). Common crucible use may be as follows. A residue or precipitate in a chemical analysis method can be collected or filtered from some sample or solution on special "ashless" filter paper. The crucible and lid to be used are pre-weighed very accurately on an analytical balance. After some possible washing and/or pre-drying of this filtrate, the residue on the filter paper can be placed in the crucible and fired (heated at very high temperature) until all the volatiles and moisture are driven out of the sample residue in the crucible. The "ashless" filter paper is completely burned up in this process. The crucible with the sample and lid is allowed to cool in a desiccator. The crucible and lid with the sample inside are weighed very accurately again only after it has completely cooled to room temperature (higher temperature would cause air currents around the balance giving inaccurate results). The mass of the empty, pre-weighed crucible and lid is subtracted from this result to yield the mass of the completely dried residue in the crucible. A


id: cryofixation-20260505-0
file: data/en.wikipedia.org/wiki/Cryofixation-0.md
category: reference
title: Cryofixation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cryofixation
date_saved: 2026-05-05T10:04:05.506913+00:00
instance: kb-cron
parent: cryofixation-20260505-0
summary:
Cryofixation is a technique for fixation or stabilisation of biological materials as the first step in specimen preparation for the electron microscopy and cryo-electron microscopy. Typical specimens for cryofixation include small samples of plant or animal tissue, cell suspensions of microorganisms or cultured cells, suspensions of viruses or virus capsids and samples of purified macromolecules, especially proteins. Types of cryo-fixation are freezing-drying, freezing-substitution and freezing-etching. == Plunge freezing == The method involves ultra-rapid cooling of small tissue or cell samples to the temperature of liquid nitrogen (−196 °C) or below, stopping all motion and metabolic activity and preserving the internal structure by freezing all fluid phases solid. Typically, a sample is plunged into liquid nitrogen or into liquid ethane or liquid propane in a container cooled by liquid nitrogen. The ultimate objective is to freeze the specimen so rapidly (at 104 to 106 K per second) that ice crystals are unable to form, or are prevented from growing big enough to cause damage to the specimen's ultrastructure. The formation of samples containing specimens in amorphous ice is the "holy grail" of biological cryomicroscopy. In practice, it is very difficult to achieve high enough cooling rates to produce amorphous ice in


id: cryogenic-electron-microscopy-20260505-0
file: data/en.wikipedia.org/wiki/Cryogenic_electron_microscopy-0.md
category: reference
title: Cryogenic electron microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cryogenic_electron_microscopy
date_saved: 2026-05-05T10:04:06.678811+00:00
instance: kb-cron
parent: cryogenic-electron-microscopy-20260505-0
summary:
Cryogenic electron microscopy (cryo-EM) is a transmission electron microscopy technique applied to samples cooled to cryogenic temperatures. Developed in the 1970s, advances in detector technology and software allow biomolecular structures to be imaged at near-atomic resolution. The approach has become a popular alternative to X-ray crystallography or NMR spectroscopy in structural biology. When scanning biological specimens, sample structure is preserved by embedding the specimens in vitreous ice. An aqueous sample solution is applied to a grid-mesh and plunge-frozen in liquid ethane or a mixture of liquid ethane and propane. The 2017 Nobel Prize in Chemistry was awarded to Jacques Dubochet, Joachim Frank, and Richard Henderson "for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution." Nature Methods also named cryo-EM as the "Method of the Year" in 2015. == History == === Early development === In the 1960s, transmission electron microscopy of biological samples was limited because of radiation damage from the high energy electron beams. Scientists hypothesized that examining specimens at low temperatures would reduce beam-induced radiation damage. Both liquid helium (−269 °C or 4 K or −452 °F) and liquid nitrogen (−195.79 °C or 77 K or −320 °F) were considered as cryogens, however high


id: cryogenic-electron-microscopy-20260505-1
file: data/en.wikipedia.org/wiki/Cryogenic_electron_microscopy-1.md
category: reference
title: Cryogenic electron microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cryogenic_electron_microscopy
date_saved: 2026-05-05T10:04:06.678811+00:00
instance: kb-cron
parent: cryogenic-electron-microscopy-20260505-0
summary:
Scanning electron cryomicroscopy (cryoSEM) is a scanning electron microscopy technique with a scanning electron microscope's cold stage in a cryogenic chamber. === Technique of use and data analysis === ==== Electron cryotomography ==== In electron cryotomography (cyro-ET), many pictures of a sample are taken from different angles using a tilting mechanism. The images are combined to create a 3D model (map) of ~1–4 nm resolution. ==== Single particle analysis ==== SPA or single-particle cyro-EM is the method used to obtain near-atomic resolution (<1 nm) models of biomolecules. It is what the 2017 Nobel Prize refers to. In SPA, a large collection of cyro-TEM images are automatically sorted into classes. Within each class, the images are combined to reduce noise and to create a 3D model of the class of particles, a 3D "map". The main innovation compared to cyro-ET is the combination of images from similar objects. When combined with a knowledge of time progression, the result is time-resolved cyro-TEM. ===== Comparisons to X-ray crystallography ===== Traditionally, X-ray crystallography has been the most popular technique for determining the 3D structures of biological molecules. However, the aforementioned improvements in cryo-EM have increased its popularity as a tool for examining the details


id: cryogenic-electron-microscopy-20260505-2
file: data/en.wikipedia.org/wiki/Cryogenic_electron_microscopy-2.md
category: reference
title: Cryogenic electron microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cryogenic_electron_microscopy
date_saved: 2026-05-05T10:04:06.678811+00:00
instance: kb-cron
parent: cryogenic-electron-microscopy-20260505-0
summary:
== Image processing in cryo-TEM == Even though in the majority of approaches in electron microscopy one tries to get the best resolution image of the material, it is not always the case in cryo-TEM. Besides all the benefits of high resolution images, the signal to noise ratio remains the main hurdle that prevents assigning orientation to each particle. For example, in macromolecule complexes, there are several different structures that are being projected from 3D to 2D during imaging and if they are not distinguished the result of image processing will be a blur. That is why the probabilistic approaches become more powerful in this type of investigation. There are two popular approaches that are widely used nowadays in cryo-EM image processing, the maximum likelihood approach that was discovered in 1998 and relatively recently adapted Bayesian approach. The maximum likelihood estimation approach comes to this field from the statistics. Here, all the possible orientations of particles are summed up to get the resulting probability distribution. We can compare this to a typical least square estimation where particles get exact orientations per image. This way, the particles in the sample get "fuzzy" orientations after calculations, weighted by corresponding probabilities. The whole


id: cyclotron-motion-20260505-0
file: data/en.wikipedia.org/wiki/Cyclotron_motion-0.md
category: reference
title: Cyclotron motion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cyclotron_motion
date_saved: 2026-05-05T10:04:07.875335+00:00
instance: kb-cron
parent: cyclotron-motion-20260505-0
summary:
In physics, cyclotron motion, also known as gyromotion, refers to the circular motion exhibited by charged particles in a uniform magnetic field. The circular trajectory of a particle in cyclotron motion is characterized by an angular frequency referred to as the cyclotron frequency or gyrofrequency and a radius referred to as the cyclotron radius, gyroradius, or Larmor radius. For a particle with charge q {\displaystyle q} and mass m {\displaystyle m} initially moving with speed v ⊥ {\displaystyle v_{\perp }} perpendicular to the direction of a uniform magnetic field B {\displaystyle B} , the cyclotron radius is: r c = m v ⊥ | q | B {\displaystyle r_{\rm {c}}={\frac {mv_{\perp }}{|q|B}}} and the cyclotron frequency is: ω c = | q | B m . {\displaystyle \omega _{\rm {c}}={\frac {|q|B}{m}}.} An external oscillating field matching the cyclotron frequency, ω = ω c , {\displaystyle \omega =\omega _{c},} will accelerate the particles, a phenomenon known as cyclotron resonance. This resonance is the basis for many scientific and engineering uses of cyclotron motion. In quantum mechanical systems, the energies of cyclotron orbits are quantized into discrete Landau levels, which contribute to Landau diamagnetism and lead to oscillatory electronic phenomena like the


id: dark-field-x-ray-microscopy-20260505-0
file: data/en.wikipedia.org/wiki/Dark-field_X-ray_microscopy-0.md
category: reference
title: Dark-field X-ray microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark-field_X-ray_microscopy
date_saved: 2026-05-05T10:04:09.080940+00:00
instance: kb-cron
parent: dark-field-x-ray-microscopy-20260505-0
summary:
Dark-field X-ray microscopy (DFXM or DFXRM) is an imaging technique used for multiscale structural characterisation. It is capable of mapping deeply embedded structural elements with nm-resolution using synchrotron X-ray diffraction-based imaging. The technique works by using scattered X-rays to create a high degree of contrast, and by measuring the intensity and spatial distribution of the diffracted beams, it is possible to obtain a three-dimensional map of the sample's structure, orientation, and local strain. == History == The first experimental demonstration of dark-field X-ray microscopy was reported in 2006 by a group at the European Synchrotron Radiation Facility in Grenoble, France. Since then, the technique has been rapidly evolving and has shown great promise in multiscale structural characterization. Its development is largely due to advances in synchrotron X-ray sources, which provide highly collimated and intense beams of X-rays. The development of dark-field X-ray microscopy has been driven by the need for non-destructive imaging of bulk crystalline samples at high resolution, and it continues to be an active area of research today. However, dark-field microscopy, dark-field scanning transmission X-ray microscopy, and soft dark-field X-ray microscopy has long been used to map deeply embedded structural elements. == Principles and instrumentation == In this


id: dark-field-x-ray-microscopy-20260505-1
file: data/en.wikipedia.org/wiki/Dark-field_X-ray_microscopy-1.md
category: reference
title: Dark-field X-ray microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dark-field_X-ray_microscopy
date_saved: 2026-05-05T10:04:09.080940+00:00
instance: kb-cron
parent: dark-field-x-ray-microscopy-20260505-0
summary:
Differential-aperture X-ray structural microscopy (DAXM): DAXM is a synchrotron X-ray method capable of delivering precise information about the local structure and crystallographic orientation in three dimensions at a spatial resolution of less than one micron. It also provides angular precision and local elastic strain with high accuracy a wide range of materials, including single crystals, polycrystals, composites, and materials with varying properties. Bragg Coherent diffraction imaging (BCDI): BCDI is an advanced microscopy technique introduced in 2006 to study crystalline nanomaterials' 3D structure. BCDI has applications in diverse areas, including in situ studies of corrosion, probing dissolution processes, and simulating diffraction patterns to understand atomic displacement. Ptychography is a computational imaging method used in microscopy to generate images by processing multiple coherent interference patterns. It provides advantages such as high-resolution imaging, phase retrieval, and lensless imaging capabilities. Diffraction Contrast Tomography (DCT): DCT is a method that uses coherent X-rays to generate three-dimensional grain maps of polycrystalline materials. DCT enables visualization of crystallographic information within samples, aiding in the analysis of materials' structural properties, defects, and grain orientations. Three-dimensional X-ray diffraction (3DXRD): 3DXRD is a synchrotron-based technique that provides information about the crystallographic orientation of individual grains in polycrystalline materials. It can


id: diaphonization-20260505-0
file: data/en.wikipedia.org/wiki/Diaphonization-0.md
category: reference
title: Diaphonization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Diaphonization
date_saved: 2026-05-05T10:04:10.260401+00:00
instance: kb-cron
parent: diaphonization-20260505-0
summary:
Diaphonization (or diaphonisation), also known as clearing and staining, is a staining technique used on animal specimens that first renders the body of the animal transparent by bathing it in trypsin, and then stains the bones and cartilage with various dyes, usually alizarin red and alcian blue. == History == Diaphonization was first developed by German anatomist Oskar Schultze in 1897, and later was modified by numerous researchers. == Technique == Clearing renders the animals transparent and is achieved by bathing the specimens in a soup of trypsin, a digestive enzyme that slowly breaks down flesh. The dyes alizarin red and alcian blue are most commonly used in the staining of bone and cartilage accordingly. When cleared, the specimen is put in glycerin. Despite its merits, diaphonization is not widely used in the scientific field. Advancements in imaging technology have rendered the practice all but obsolete, though it is expanding as an art form. Diaphonization is not suitable for animals longer than 30 centimeters (except for snakes) due to the limited ability of the trypsin bath to penetrate the tissues of larger animals. It is usually used to preserve animals that are too delicate to dissect, and instead are kept


id: dielectric-thermal-analysis-20260505-0
file: data/en.wikipedia.org/wiki/Dielectric_thermal_analysis-0.md
category: reference
title: Dielectric thermal analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dielectric_thermal_analysis
date_saved: 2026-05-05T10:04:11.443479+00:00
instance: kb-cron
parent: dielectric-thermal-analysis-20260505-0
summary:
Dielectric thermal analysis (DETA), or dielectric analysis (DEA), is a materials science technique similar to dynamic mechanical analysis except that an oscillating electrical field is used instead of a mechanical force. For investigation of the curing behavior of thermosetting resin systems, composite materials, adhesives and paints, Dielectric Analysis (DEA) can be used in accordance with ASTM E 2038 or E 2039. The great advantage of DEA is that it can be employed not only on a laboratory scale, but also in process. == Measuring principle == In a typical test, the sample is placed in contact with two electrodes (the dielectric sensor) and a sinusoidal voltage (the excitation) is applied to one electrode. The resulting sinusoidal current (the response) is measured at the second electrode. The response signal is attenuated in amplitude and shifted in phase in relation to the mobility of the ions and alignment of the dipoles. Dipoles in the material will attempt to align with the electric field and ions (present as impurities) will move toward the electrode of opposite polarity. The dielectric properties of permittivity ε' and loss factor ε" are then calculated from this measured amplitude and phase change. == References ==


id: differential-dynamic-microscopy-20260505-0
file: data/en.wikipedia.org/wiki/Differential_dynamic_microscopy-0.md
category: reference
title: Differential dynamic microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Differential_dynamic_microscopy
date_saved: 2026-05-05T10:04:12.670972+00:00
instance: kb-cron
parent: differential-dynamic-microscopy-20260505-0
summary:
Differential dynamic microscopy (DDM) is an imaging-based optical technique that enables performing light scattering-like experiments by means of a conventional optical microscope. It uses time sequences of microscope images to extract dynamic information about microscopic fluctuations over a range of length scales and time delays, analogous to what is obtained in dynamic light scattering (DLS) experiments. DDM is suitable for typical soft materials such as liquids, gels, suspensions of colloids and polymers, liquid crystals and it has been applied to various biological systems including bacteria and cells. == History and developments == The DDM technique was introduced in 2008 by Cerbino & Trappe as a way to probe wavevector-resolved dynamics of colloidal particles using a microscope equipped with a high-speed camera, demonstrating that dynamic information similar to that obtained in DLS can be extracted from time-lapse images taken in real space. This foundational paper has accumulated several citations, establishing the unique capability of DDM to combine imaging capabilities with scattering-based wavevector analysis. Shortly thereafter, Giavazzi et al. discussed extensions to other imaging modalities, also based on fluorescence, and clarified the connections of DDM to related imaging-based scattering methods (see below the section Relationship with other imaging-based scattering methods). Subsequent studies


id: differential-dynamic-microscopy-20260505-1
file: data/en.wikipedia.org/wiki/Differential_dynamic_microscopy-1.md
category: reference
title: Differential dynamic microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Differential_dynamic_microscopy
date_saved: 2026-05-05T10:04:12.670972+00:00
instance: kb-cron
parent: differential-dynamic-microscopy-20260505-0
summary:
Measurement speed: DDM requires extended acquisition times (minutes to hours) compared to DLS (seconds), making DLS preferred for rapid, routine measurements. Analysis time: Data analysis is computationally intensive. While traditional CPU-based processing required minutes to hours per dataset, recent GPU-accelerated implementations (e.g. fastDDM) reduce this to seconds, enabling high-throughput workflows. Commercial maturity: DLS instruments and software are mature and widely available; DDM requires custom setups or adapted commercial microscopes with specialized analysis software. Optical contrast requirement: DDM performance depends critically on signal contrast. Weakly scattering samples may require careful illumination optimization or fluorescent labeling. Dynamic range trade-offs: Lowest accessible q-values (longest length scales) correspond to very slow dynamics requiring extended acquisition; highest q-values require high magnification and frame rates, creating practical trade-offs in microscope configuration. == Applicability and working principle == The concentration–intensity proportionality, which ensures the validity of the DDM framework, holds in two primary classes of DDM implementations: Scattering-based DDM: where image intensity arises from the interference between a strong transmitted beam and weakly scattered light, as in bright field, phase contrast, or polarized imaging. Fluorescence-based DDM: where images result from the incoherent summation of fluorescence emissions from labeled particles or structures, as in fluorescence or confocal imaging.


id: differential-dynamic-microscopy-20260505-2
file: data/en.wikipedia.org/wiki/Differential_dynamic_microscopy-2.md
category: reference
title: Differential dynamic microscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Differential_dynamic_microscopy
date_saved: 2026-05-05T10:04:12.670972+00:00
instance: kb-cron
parent: differential-dynamic-microscopy-20260505-0
summary:
== Applications == DDM was initially used to characterize the dynamics of colloidal particles undergoing Brownian motion in dilute and concentrated suspensions, extracting diffusion coefficients and other hydrodynamic parameters from the wavevector dependence of decorrelation rates. DDM has been extended to measure dynamics in complex fluids, including aggregation processes of nanoparticles and dynamics of anisotropic colloids. DDM has been widely applied to quantify bacterial motion and motility, providing ensemble-averaged parameters such as population swim speed, diffusivity, and run–tumble statistics without single-particle tracking. Confocal and fluorescence implementations further enable measurements in fluorescent and optically challenging samples, including concentrated and multiply scattering systems. Selected application areas include: Particle sizing and size distributions: DDM can be used for particle sizing by extracting diffusion coefficients and converting them to hydrodynamic sizes via the Stokes–Einstein equation. This can be extended to multimodal size distributions and mixtures, where DDM provides size information even when individual particles are not resolved. Protein sizing and macromolecular characterization: DDM has been extended to characterize proteins at dilute concentrations of a few milligrams per milliliter, achieving hydrodynamic radius measurements in excellent agreement with commercial DLS instruments while requiring only microliters of sample. Turbid and concentrated suspensions: DDM has been used to


id: differential-scanning-calorimetry-20260505-0
file: data/en.wikipedia.org/wiki/Differential_scanning_calorimetry-0.md
category: reference
title: Differential scanning calorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Differential_scanning_calorimetry
date_saved: 2026-05-05T10:04:13.886915+00:00
instance: kb-cron
parent: differential-scanning-calorimetry-20260505-0
summary:
Differential scanning calorimetry (DSC) is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and a reference is measured as a function of temperature. Both the sample and reference are maintained at nearly the same temperature throughout the experiment. Generally, the temperature program for a DSC analysis is designed such that the sample holder temperature increases linearly as a function of time. The reference sample should have a well-defined heat capacity over the range of temperatures to be scanned. Additionally, the reference sample must be stable, of high purity, and must not experience much change across the temperature scan. Typically, reference standards have been metals such as indium, tin, bismuth, and lead, but other standards such as polyethylene and fatty acids have been proposed to study polymers and organic compounds, respectively. The technique was developed by E. S. Watson and M. J. O'Neill in 1962, and introduced commercially at the 1963 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. The first adiabatic differential scanning calorimeter that could be used in biochemistry was developed by P. L. Privalov and D. R. Monaselidze in 1964 at Institute of Physics in Tbilisi,


id: differential-scanning-calorimetry-20260505-1
file: data/en.wikipedia.org/wiki/Differential_scanning_calorimetry-1.md
category: reference
title: Differential scanning calorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Differential_scanning_calorimetry
date_saved: 2026-05-05T10:04:13.886915+00:00
instance: kb-cron
parent: differential-scanning-calorimetry-20260505-0
summary:
The result of a DSC experiment is a curve of heat flux versus temperature or versus time. There are two different conventions: exothermic reactions in the sample shown with a positive or negative peak, depending on the kind of technology used in the experiment. This curve can be used to calculate enthalpies of transitions. This is done by integrating the peak corresponding to a given transition. It can be shown that the enthalpy of transition can be expressed using the following equation: Δ H = K A {\displaystyle \Delta H=KA} where Δ H {\displaystyle \Delta H} is the enthalpy of transition, K {\displaystyle K} is the calorimetric constant, and A {\displaystyle A} is the area under the curve. The calorimetric constant will vary from instrument to instrument, and can be determined by analyzing a well-characterized sample with known enthalpies of transition. == Applications == Differential scanning calorimetry can be used to measure a number of characteristic properties of a sample. Using this technique it is possible to observe fusion and crystallization events as well as glass transition temperatures Tg. DSC can also be used to study oxidation, as well as other chemical reactions. Glass transitions may occur as the temperature


id: differential-scanning-calorimetry-20260505-2
file: data/en.wikipedia.org/wiki/Differential_scanning_calorimetry-2.md
category: reference
title: Differential scanning calorimetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Differential_scanning_calorimetry
date_saved: 2026-05-05T10:04:13.886915+00:00
instance: kb-cron
parent: differential-scanning-calorimetry-20260505-0
summary:
== Examples == The technique is widely used across a range of applications, both as a routine quality test and as a research tool. The equipment is easy to calibrate, using low melting indium at 156.5985 °C for example, and is a rapid and reliable method of thermal analysis. === Polymers === DSC is used widely for examining polymeric materials to determine their thermal transitions. Important thermal transitions include the glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm). The observed thermal transitions can be utilized to compare materials, although the transitions alone do not uniquely identify composition. The composition of unknown materials may be completed using complementary techniques such as IR spectroscopy. Melting points and glass transition temperatures for most polymers are available from standard compilations, and the method can show polymer degradation by the lowering of the expected melting temperature. Tm depends on the molecular weight of the polymer and thermal history. The percent crystalline content of a polymer can be estimated from the crystallization/melting peaks of the DSC graph using reference heats of fusion found in the literature. DSC can also be used to study thermal degradation of polymers using an approach such as Oxidative


id: differential-thermal-analysis-20260505-0
file: data/en.wikipedia.org/wiki/Differential_thermal_analysis-0.md
category: reference
title: Differential thermal analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Differential_thermal_analysis
date_saved: 2026-05-05T10:04:15.065279+00:00
instance: kb-cron
parent: differential-thermal-analysis-20260505-0
summary:
Differential thermal analysis (DTA) is a thermoanalytic technique that is similar to differential scanning calorimetry. In DTA, the material under study and an inert reference are made to undergo identical thermal cycles, (i.e., same cooling or heating programme) while recording any temperature difference between sample and reference. This differential temperature is then plotted against time, or against temperature (DTA curve, or thermogram). Changes in the sample, either exothermic or endothermic, can be detected relative to the inert reference. Thus, a DTA curve provides data on the transformations that have occurred, such as glass transitions, crystallization, melting and sublimation. The area under a DTA peak is the enthalpy change and is not affected by the heat capacity of the sample. == Apparatus == A DTA consists of a sample holder, thermocouples, sample containers and a ceramic or metallic block; a furnace; a temperature programmer; and a recording system. The key feature is the existence of two thermocouples connected to a voltmeter. One thermocouple is placed in an inert material such as Al2O3, while the other is placed in a sample of the material under study. As the temperature is increased, there will be a brief deflection of the voltmeter if the


id: dna-encoded-chemical-library-20260505-0
file: data/en.wikipedia.org/wiki/DNA-encoded_chemical_library-0.md
category: reference
title: DNA-encoded chemical library
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/DNA-encoded_chemical_library
date_saved: 2026-05-05T10:04:16.238098+00:00
instance: kb-cron
parent: dna-encoded-chemical-library-20260505-0
summary:
DNA-encoded chemical libraries (DECL) is a technology for the synthesis and screening on an unprecedented scale of collections of small molecule compounds. DECL is used in medicinal chemistry to bridge the fields of combinatorial chemistry and molecular biology. The aim of DECL technology is to accelerate the drug discovery process and in particular early phase discovery activities such as target validation and hit identification. DECL technology involves the conjugation of chemical compounds or building blocks to short DNA fragments that serve as identification bar codes and in some cases also direct and control the chemical synthesis. The technique enables the mass creation and interrogation of libraries via affinity selection, typically on an immobilized protein target. A homogeneous method for screening DNA-encoded libraries (DELs) has recently been developed which uses water-in-oil emulsion technology to isolate, count and identify individual ligand-target complexes in a single-tube approach. In contrast to conventional screening procedures such as high-throughput screening, biochemical assays are not required for binder identification, in principle allowing the isolation of binders to a wide range of proteins historically difficult to tackle with conventional screening technologies. So, in addition to the general discovery of target specific molecular compounds, the availability of binders to


id: dna-encoded-chemical-library-20260505-1
file: data/en.wikipedia.org/wiki/DNA-encoded_chemical_library-1.md
category: reference
title: DNA-encoded chemical library
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/DNA-encoded_chemical_library
date_saved: 2026-05-05T10:04:16.238098+00:00
instance: kb-cron
parent: dna-encoded-chemical-library-20260505-0
summary:
The concept of DNA-encoding was first described in a theoretical paper by Sydney Brenner and Richard Lerner in 1992 in which was proposed to link each molecule of a chemically synthesized entity to a particular oligonucleotide sequence constructed in parallel and to use this encoding genetic tag to identify and enrich active compounds. In 1993 the first practical implementation of this approach was presented by J Nielsen, S. Brenner and K. Janda and similarly by the group of M.A. Gallop. Brenner and Janda suggested to generate individual encoded library members by an alternating parallel combinatorial synthesis of the heteropolymeric chemical compound and the appropriate oligonucleotide sequence on the same bead in a “split-&-pool”-based fashion (see below). Since unprotected DNA is restricted to a narrow window of conventional reaction conditions, until the end of the 1990s a number of alternative encoding strategies were envisaged (i.e. MS-based compound tagging, peptide encoding, haloaromatic tagging, encoding by secondary amines, semiconductor devices.), mainly to avoid inconvenient solid phase DNA synthesis and to create easily screenable combinatorial libraries in high-throughput fashion. However, the selective amplificability of DNA greatly facilitates library screening and it becomes indispensable for the encoding of organic compounds libraries of this unprecedented size.


id: dna-encoded-chemical-library-20260505-2
file: data/en.wikipedia.org/wiki/DNA-encoded_chemical_library-2.md
category: reference
title: DNA-encoded chemical library
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/DNA-encoded_chemical_library
date_saved: 2026-05-05T10:04:16.238098+00:00
instance: kb-cron
parent: dna-encoded-chemical-library-20260505-0
summary:
=== Split-&-Pool DNA Encoding === In order to apply combinatorial chemistry for the synthesis of DNA-encoded chemical libraries, a Split-&-Pool approach was pursued. Initially a set of unique DNA-oligonucleotides (n) each containing a specific coding sequence is chemically conjugated to a corresponding set of small organic molecules. Consequently, the oligonucleotide-conjugate compounds are mixed ("Pool") and divided ("Split") into a number of groups (m). In appropriate conditions a second set of building blocks (m) are coupled to the first one and a further oligonucleotide which is coding for the second modification is enzymatically introduced before mixing again. This “split-&-pool” steps can be iterated a number of times (r) increasing at each round the library size in a combinatorial manner (i.e. (n x m)r). Alternatively, peptide nucleic acids have been used to encode libraries prepared by "split-&-pool" method. A benefit of PNA-encoding is that the chemistry can be performed by standard SPPS. === Stepwise coupling of coding DNA fragments to nascent organic molecules === A promising strategy for the construction of DNA-encoded libraries is represented by the use of multifunctional building blocks covalently conjugated to an oligonucleotide serving as a “core structure” for library synthesis. In a ‘pool-and-split’ fashion a set of


id: dna-encoded-chemical-library-20260505-3
file: data/en.wikipedia.org/wiki/DNA-encoded_chemical_library-3.md
category: reference
title: DNA-encoded chemical library
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/DNA-encoded_chemical_library
date_saved: 2026-05-05T10:04:16.238098+00:00
instance: kb-cron
parent: dna-encoded-chemical-library-20260505-0
summary:
In 2001 David Liu and co-workers showed that complementary DNA oligonucleotides can be used to assist certain synthetic reactions, which do not efficiently take place in solution at low concentration. A DNA-heteroduplex was used to accelerate the reaction between chemical moieties displayed at the extremities of the two DNA strands. Furthermore, the "proximity effect", which accelerates bimolecular reaction, was shown to be distance-independent (at least within a distance of 30 nucleotides). In a sequence-programmed fashion oligonucleotides carrying one chemical reactant group were hybridized to complementary oligonucleotide derivatives carrying a different reactive chemical group. The proximity conferred by the DNA hybridization drastically increases the effective molarity of the reaction reagents attached to the oligonucleotides, enabling the desired reaction to occur even in an aqueous environment at concentrations which are several orders of magnitude lower than those needed for the corresponding conventional organic reaction not DNA-templated. Using a DNA-templated set-up and sequence-programmed synthesis Liu and co-workers generated a 64-member compound DNA encoded library of macrocycles. == 3-Dimensional proximity-based technology (YoctoReactor technology) == The YoctoReactor (yR) is a 3D proximity-driven approach which exploits the self-assembling nature of DNA oligonucleotides into 3, 4 or 5-way junctions to direct small molecule synthesis at the center


id: dna-encoded-chemical-library-20260505-4
file: data/en.wikipedia.org/wiki/DNA-encoded_chemical_library-4.md
category: reference
title: DNA-encoded chemical library
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/DNA-encoded_chemical_library
date_saved: 2026-05-05T10:04:16.238098+00:00
instance: kb-cron
parent: dna-encoded-chemical-library-20260505-0
summary:
== Decoding of DNA-encoded chemical libraries == Following selection from DNA-encoded chemical libraries, the decoding strategy for the fast and efficient identification of the specific binding compounds is crucial for the further development of the DEL technology. So far, Sanger-sequencing-based decoding, microarray-based methodology and high-throughput sequencing techniques represented the main methodologies for the decoding of DNA-encoded library selections. === Sanger sequencing-based decoding === Although many authors implicitly envisaged a traditional Sanger sequencing-based decoding, the number of codes to sequence simply according to the complexity of the library is definitely an unrealistic task for a traditional Sanger sequencing approach. Nevertheless, the implementation of Sanger sequencing for decoding DNA-encoded chemical libraries in high-throughput fashion was the first to be described. After selection and PCR amplification of the DNA-tags of the library compounds, concatamers containing multiple coding sequences were generated and ligated into a vector. Following Sanger sequencing of a representative number of the resulting colonies revealed the frequencies of the codes present in the DNA-encoded library sample before and after selection. === Microarray-based decoding === A DNA microarray is a device for high-throughput investigations widely used in molecular biology and in medicine. It consists of an arrayed series of microscopic spots (‘features’


id: dna-encoded-chemical-library-20260505-5
file: data/en.wikipedia.org/wiki/DNA-encoded_chemical_library-5.md
category: reference
title: DNA-encoded chemical library
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/DNA-encoded_chemical_library
date_saved: 2026-05-05T10:04:16.238098+00:00
instance: kb-cron
parent: dna-encoded-chemical-library-20260505-0
summary:
Peptide nucleic acids (PNAs) are synthetic oligonucleotides in which the sugar-phosphate backbone of the DNA or RNA is replaced by a neutral N-(2-aminoethyl)-glycine peptide-like backbone . This allows PNAs to hybridize with complementary DNA or RNA with high affinity and specificity, maintaining their ability to be amplified via polymerase chain reaction (PCR). Unlike DNA/RNA, PNAs are able to resist degradation by nucleases and proteases . In a PNA-encoded library system, unique PNA sequences serve as molecular tags that are covalently attached to small molecules that are produced using combinatorial methods that generate large collections of related compounds. These PNA tags act as barcodes that encode the identity of the PNA allowing for downstream identification . PNA libraries are synthesized using solid-phase peptide synthesis (SPPS), allowing library assembly on resin similar to other peptide libraries. This contrasts with DNA-encoded libraries, which often require enzymatic ligation steps and can be limited by the chemical properties of DNA . The neutrality and stability of the PNA backbone means that PNA tags can tolerate conditions that might degrade DNA tags, and the strong hybridization to complementary nucleic acids which allows PNA tags to be decoded wither by direct hybridization or by conversion into DNA,


id: du-no-y-ring-method-20260505-0
file: data/en.wikipedia.org/wiki/Du_Noüy_ring_method-0.md
category: reference
title: Du Noüy ring method
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Du_Noüy_ring_method
date_saved: 2026-05-05T10:04:17.394583+00:00
instance: kb-cron
parent: du-no-y-ring-method-20260505-0
summary:
In surface science, the du Noüy ring method is a technique for measuring the surface tension of a liquid. This technique was proposed by Pierre Lecomte du Noüy in 1925. The measurement is performed with a force tensiometer, which typically uses an electrobalance to measure the excess force caused by the liquid being pulled up and automatically calculates and displays the surface tension corresponding to the force. Earlier, torsion wire balances were commonly used. == Description == The method involves slowly lifting a ring, often made of platinum, from the surface of a liquid. The force, F, required to raise the ring from the liquid's surface is measured and related to the liquid's surface tension γ: F = w ring + 2 π ⋅ ( r i + r a ) ⋅ γ , {\displaystyle F=w_{\text{ring}}+2\pi \cdot (r_{\text{i}}+r_{\text{a}})\cdot \gamma ,} where ri is the radius of the inner ring of the liquid film pulled, and ra is the radius of the outer ring of the liquid film. wring is the weight of the ring minus the buoyant force due to the part of the ring below the liquid surface. When the ring's thickness is much smaller than its diameter, this


id: dynamic-light-scattering-20260505-0
file: data/en.wikipedia.org/wiki/Dynamic_light_scattering-0.md
category: reference
title: Dynamic light scattering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynamic_light_scattering
date_saved: 2026-05-05T10:04:18.544311+00:00
instance: kb-cron
parent: dynamic-light-scattering-20260505-0
summary:
Dynamic light scattering (DLS) is a technique in physics that can be used to determine the size distribution profile of small particles in suspension or polymers in solution. In the scope of DLS, temporal fluctuations are usually analyzed using the intensity or photon autocorrelation function (also known as photon correlation spectroscopy – PCS or quasi-elastic light scattering – QELS). In the time domain analysis, the autocorrelation function (ACF) usually decays starting from zero delay time, and faster dynamics due to smaller particles lead to faster decorrelation of scattered intensity trace. It has been shown that the intensity ACF is the Fourier transform of the power spectrum, and therefore the DLS measurements can be equally well performed in the spectral domain. DLS can also be used to probe the behavior of complex fluids such as concentrated polymer solutions. == Setup == A monochromatic light source, usually a laser, is shot through a polarizer and into a sample. The scattered light then goes through a second polarizer where it is collected by a photomultiplier and the resulting image is projected onto a screen. This is known as a speckle pattern (Figure 1). All of the molecules in the solution are being hit


id: dynamic-light-scattering-20260505-1
file: data/en.wikipedia.org/wiki/Dynamic_light_scattering-1.md
category: reference
title: Dynamic light scattering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynamic_light_scattering
date_saved: 2026-05-05T10:04:18.544311+00:00
instance: kb-cron
parent: dynamic-light-scattering-20260505-0
summary:
== Multiple scattering == Dynamic light scattering provides insight into the dynamic properties of soft materials by measuring single scattering events, meaning that each detected photon has been scattered by the sample exactly once. In principle, the DLS measurements can be performed with the detector positioned at any angle. The choice of the best angle depends on the sample properties, such as turbidity and particle size. Back scattering detection (e.g., 173° or 175°) is particularly interesting for turbid and highly concentrated samples, which contain large particles. Side scattering detection (90°) is recommended for weakly scattering samples, including small particles and transparent samples. Finally, forward scattering detection (e.g., 13° or 15°) is suitable for detection of samples containing small particles with few large particles. Some DLS instruments in the market also allow automatic angle selection based on a continuous transmittance measurement. At the lower end of the turbidity range, the Cavity Amplified Scattering Spectroscopy method makes use of an integrating cavity to elongate photon paths through quasi non-scattering samples. As opposed to conventional DLS instruments, this method is angle independent as it probes samples isotropically from all directions. Even though the DLS measurement using a single-angle detection has been the most


id: dynamic-light-scattering-20260505-2
file: data/en.wikipedia.org/wiki/Dynamic_light_scattering-2.md
category: reference
title: Dynamic light scattering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynamic_light_scattering
date_saved: 2026-05-05T10:04:18.544311+00:00
instance: kb-cron
parent: dynamic-light-scattering-20260505-0
summary:
where λ is the incident laser wavelength, n0 is the solvent refractive index and θ is the angle at which the detector is located with respect to the sample cell. The refractive index of the solvent plays a crucial role in light scattering and is important to calculate the Stokes radius from the Stokes-Einstein equation. Therefore, previous refractive index data from the scattering medium should be evaluated with dedicated instruments, known as refractometers. Alternatively, DLS instruments containing a refractive index measurement module allow a good estimative for this important parameter within ±0.5%, which is the accuracy defined by ISO 22412:2017 for refractive index values required for DLS. Besides the refractive index of the medium, the refractive index of the particles is only necessary when analyzing larger particle size (usually above 100 nm) and volume- or number-weighted size distributions are needed. In these cases, prior knowledge of the refractive index and absorbance of the material is required in order to apply the Mie scattering. Depending on the anisotropy and polydispersity of the system, a resulting plot of (Γ/q2) vs. q2 may or may not show an angular dependence. Small spherical particles will show no angular dependence, hence no anisotropy. A plot


id: dynamic-light-scattering-20260505-3
file: data/en.wikipedia.org/wiki/Dynamic_light_scattering-3.md
category: reference
title: Dynamic light scattering
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynamic_light_scattering
date_saved: 2026-05-05T10:04:18.544311+00:00
instance: kb-cron
parent: dynamic-light-scattering-20260505-0
summary:
=== CONTIN algorithm === An alternative method for analyzing the autocorrelation function can be achieved through an inverse Laplace transform known as CONTIN developed by Steven Provencher. The CONTIN analysis is ideal for heterodisperse, polydisperse, and multimodal systems that cannot be resolved with the cumulant method. The resolution for separating two different particle populations is approximately a factor of five or higher and the difference in relative intensities between two different populations should be less than 1:10−5. === Maximum entropy method === The Maximum entropy method is an analysis method that has great developmental potential. The method is also used for the quantification of sedimentation velocity data from analytical ultracentrifugation. The maximum entropy method involves several iterative steps to minimize the deviation of the fitted data from the experimental data and subsequently reduce the χ2 of the fitted data. == Scattering of non-spherical particles == If the particle in question is not spherical, the rotational motion must be considered as well because the scattering of the light will be different depending on orientation. According to Pecora, rotational Brownian motion will affect the scattering when a particle fulfills two conditions; they must be both optically and geometrically anisotropic. Rod-shaped molecules fulfill


id: dynamic-mechanical-analysis-20260505-0
file: data/en.wikipedia.org/wiki/Dynamic_mechanical_analysis-0.md
category: reference
title: Dynamic mechanical analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynamic_mechanical_analysis
date_saved: 2026-05-05T10:04:19.735755+00:00
instance: kb-cron
parent: dynamic-mechanical-analysis-20260505-0
summary:
Dynamic mechanical analysis (abbreviated DMA) is a technique used to study and characterize materials. It is most useful for studying the viscoelastic behavior of polymers. A sinusoidal stress is applied and the strain in the material is measured, allowing one to determine the complex modulus. The temperature of the sample or the frequency of the stress are often varied, leading to variations in the complex modulus; this approach can be used to locate the glass transition temperature of the material, as well as to identify transitions corresponding to other molecular motions. == Theory == === Viscoelastic properties of materials === Polymers composed of long molecular chains have unique viscoelastic properties, which combine the characteristics of elastic solids and Newtonian fluids. The classical theory of elasticity describes the mechanical properties of elastic solids where stress is proportional to strain in small deformations. Such response to stress is independent of strain rate. The classical theory of hydrodynamics describes the properties of viscous fluid, for which stress response depends on strain rate. This solidlike and liquidlike behaviour of polymers can be modelled mechanically with combinations of springs and dashpots, making for both elastic and viscous behaviour of viscoelastic materials such as bitumen. ===


id: dynamic-mechanical-analysis-20260505-1
file: data/en.wikipedia.org/wiki/Dynamic_mechanical_analysis-1.md
category: reference
title: Dynamic mechanical analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynamic_mechanical_analysis
date_saved: 2026-05-05T10:04:19.735755+00:00
instance: kb-cron
parent: dynamic-mechanical-analysis-20260505-0
summary:
σ ( t ) γ 0 = [ ω ∫ o ∞ G ( s ) sin ⁡ ( ω s ) d s ] ⏟ shear storage modulus G ′ sin ⁡ ( ω t ) + [ ω ∫ o ∞ G ( s ) cos ⁡ ( ω s ) d s ] ⏟ shear loss modulus G ″ cos ⁡ ( ω t ) . {\displaystyle {\frac {\sigma (t)}{\gamma _{0}}}=\underbrace {[\omega \int _{o}^{\infty }G(s)\sin(\omega s)ds]} _{{\text{shear storage modulus }}G'}\sin(\omega t)+\underbrace {[\omega \int _{o}^{\infty }G(s)\cos(\omega s)ds]} _{{\text{shear loss modulus }}G''}\cos(\omega t).\,} with converging integrals, if G ( s ) → 0 {\displaystyle G(s)\rightarrow 0} for s → ∞ {\displaystyle s\rightarrow \infty } , which depend on frequency but not of time. Extension of σ ( t ) = σ 0 ⋅ sin ⁡ ( ω ⋅ t + Δ φ ) {\displaystyle \sigma (t)=\sigma _{0}\cdot \sin(\omega \cdot t+\Delta \varphi )} with trigonometric identity sin ⁡ ( x ± y ) = sin ⁡ ( x ) ⋅ cos ⁡ ( y ) ± cos ⁡ ( x ) ⋅ sin ⁡ ( y ) {\displaystyle \sin(x\pm y)=\sin(x)\cdot \cos(y)\pm \cos(x)\cdot \sin(y)} lead to σ ( t ) γ


id: dynamic-mechanical-analysis-20260505-2
file: data/en.wikipedia.org/wiki/Dynamic_mechanical_analysis-2.md
category: reference
title: Dynamic mechanical analysis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynamic_mechanical_analysis
date_saved: 2026-05-05T10:04:19.735755+00:00
instance: kb-cron
parent: dynamic-mechanical-analysis-20260505-0
summary:
Analyzers are made for both stress (force) and strain (displacement) control. In strain control, the probe is displaced and the resulting stress of the sample is measured by implementing a force balance transducer, which utilizes different shafts. The advantages of strain control include a better short time response for materials of low viscosity and experiments of stress relaxation are done with relative ease. In stress control, a set force is applied to the sample and several other experimental conditions (temperature, frequency, or time) can be varied. Stress control is typically less expensive than strain control because only one shaft is needed, but this also makes it harder to use. Some advantages of stress control include the fact that the structure of the sample is less likely to be destroyed and longer relaxation times/ longer creep studies can be done with much more ease. Characterizing low viscous materials come at a disadvantage of short time responses that are limited by inertia. Stress and strain control analyzers give about the same results as long as characterization is within the linear region of the polymer in question. However, stress control lends a more realistic response because polymers have a tendency to resist a


id: electron-backscatter-diffraction-20260505-0
file: data/en.wikipedia.org/wiki/Electron_backscatter_diffraction-0.md
category: reference
title: Electron backscatter diffraction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_backscatter_diffraction
date_saved: 2026-05-05T10:04:21.164305+00:00
instance: kb-cron
parent: electron-backscatter-diffraction-20260505-0
summary:
Electron backscatter diffraction (EBSD) is a scanning electron microscopy (SEM) technique used to study the crystallographic structure of materials. EBSD is carried out in a scanning electron microscope equipped with an EBSD detector comprising at least a phosphorescent screen, a compact lens and a low-light camera. In the microscope an incident beam of electrons hits a tilted sample. As backscattered electrons leave the sample, they interact with the atoms and are both elastically diffracted and lose energy, leaving the sample at various scattering angles before reaching the phosphor screen forming Kikuchi patterns (EBSPs). The EBSD spatial resolution depends on many factors, including the nature of the material under study and the sample preparation. They can be indexed to provide information about the material's grain structure, grain orientation, and phase at the micro-scale. EBSD is used for impurities and defect studies, plastic deformation, and statistical analysis for average misorientation, grain size, and crystallographic texture. EBSD can also be combined with energy-dispersive X-ray spectroscopy (EDS), cathodoluminescence (CL), and wavelength-dispersive X-ray spectroscopy (WDS) for advanced phase identification and materials discovery. The change and sharpness of the electron backscatter patterns (EBSPs) provide information about lattice distortion in the diffracting volume. Pattern sharpness can be


id: electron-backscatter-diffraction-20260505-1
file: data/en.wikipedia.org/wiki/Electron_backscatter_diffraction-1.md
category: reference
title: Electron backscatter diffraction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_backscatter_diffraction
date_saved: 2026-05-05T10:04:21.164305+00:00
instance: kb-cron
parent: electron-backscatter-diffraction-20260505-0
summary:
The sample should be vacuum stable. It is typically mounted using a conductive compound (e.g. an epoxy thermoset filled with Cu), which minimises image drift and sample charging under electron beam irradiation. EBSP quality is sensitive to surface preparation. Typically the sample is ground using SiC papers from 240 down to 4000 grit, and polished using diamond paste (from 9 to 1 μm) then in 50 nm colloidal silica. Afterwards, it is cleaned in ethanol, rinsed with deionised water, and dried with a hot air blower. This may be followed by ion beam polishing, for final surface preparation. Inside the SEM, the size of the measurement area determines local resolution and measurement time. Usual settings for high-quality EBSPs are 15 nA current, 20 kV beam energy, 18 mm working distance, long exposure time, and minimal CCD pixel binning. The EBSD phosphor screen is set at an 18 mm working distance and a map's step size of less than 0.5 μm for strain and dislocations density analysis. Decomposition of gaseous hydrocarbons and also hydrocarbons on the surface of samples by the electron beam inside the microscope results in carbon deposition, which degrades the quality of EBSPs inside the probed area compared


id: electron-backscatter-diffraction-20260505-2
file: data/en.wikipedia.org/wiki/Electron_backscatter_diffraction-2.md
category: reference
title: Electron backscatter diffraction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_backscatter_diffraction
date_saved: 2026-05-05T10:04:21.164305+00:00
instance: kb-cron
parent: electron-backscatter-diffraction-20260505-0
summary:
If the setup geometry is well described, it is possible to relate the bands present in the diffraction pattern to the underlying crystal and crystallographic orientation of the material within the electron interaction volume. Each band can be indexed individually by the Miller indices of the diffracting plane which formed it. In most materials, only three bands/planes intersect and are required to describe a unique solution to the crystal orientation (based on their interplanar angles). Most commercial systems use look-up tables with international crystal databases to index. This crystal orientation relates the orientation of each sampled point to a reference crystal orientation. Indexing is often the first step in the EBSD process after pattern collection. This allows for the identification of the crystal orientation at the single volume of the sample from where the pattern was collected. With EBSD software, pattern bands are typically detected via a mathematical routine using a modified Hough transform, in which every pixel in Hough space denotes a unique line/band in the EBSP. The Hough transform enables band detection, which is difficult to locate by computer in the original EBSP. Once the band locations have been detected, it is possible to relate these locations to


id: electron-backscatter-diffraction-20260505-3
file: data/en.wikipedia.org/wiki/Electron_backscatter_diffraction-3.md
category: reference
title: Electron backscatter diffraction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_backscatter_diffraction
date_saved: 2026-05-05T10:04:21.164305+00:00
instance: kb-cron
parent: electron-backscatter-diffraction-20260505-0
summary:
The indexing results are used to generate a map of the crystallographic orientation at each point on the surface being studied. Thus, scanning the electron beam in a prescribed fashion (typically in a square or hexagonal grid, correcting for the image foreshortening due to the sample tilt) results in many rich microstructural maps. These maps can spatially describe the crystal orientation of the material being interrogated and can be used to examine microtexture and sample morphology. Some maps describe grain orientation, boundary, and diffraction pattern (image) quality. Various statistical tools can measure the average misorientation, grain size, and crystallographic texture. From this dataset, numerous maps, charts and plots can be generated. The orientation data can be visualised using a variety of techniques, including colour-coding, contour lines, and pole figures. Microscope misalignment, image shift, scan distortion that increases with decreasing magnification, roughness and contamination of the specimen surface, boundary indexing failure and detector quality can lead to uncertainties in determining the crystal orientation. The EBSD signal-to-noise ratio depends on the material and decreases at excessive acquisition speed and beam current, thereby affecting the angular resolution of the measurement. == Strain measurement == Full-field displacement, elastic strain, and the GND density provide


id: electron-backscatter-diffraction-20260505-4
file: data/en.wikipedia.org/wiki/Electron_backscatter_diffraction-4.md
category: reference
title: Electron backscatter diffraction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_backscatter_diffraction
date_saved: 2026-05-05T10:04:21.164305+00:00
instance: kb-cron
parent: electron-backscatter-diffraction-20260505-0
summary:
The shifts are measured in the phosphor (detector) plane ( β 3 r 3 = 0 {\displaystyle \beta _{3}r_{3}=0} ), and the relationship is simplified; thus, eight out of the nine displacement gradient tensor components can be calculated by measuring the shift at four distinct, widely spaced regions on the EBSP. This shift is then corrected to the sample frame (flipped around Y-axis) because EBSP is recorded on the phosphor screen and is inverted as in a mirror. They are then corrected around the X-axis by 24° (i.e., 20° sample tilt plus ≈4° camera tilt and assuming no angular effect from the beam movement). Using infinitesimal strain theory, the deformation gradient is then split into elastic strain (symmetric part, where i j = j i {\displaystyle ij=ji} ), e i j {\displaystyle e_{ij}} and lattice rotations (asymmetric part, where i i = j j = 0 {\displaystyle ii=jj=0} ), ω i j {\displaystyle \omega _{ij}} . e i j = 1 2 ( β i j + β i j r ) , ω i j = 1 2 ( β i j − β i j r ) {\displaystyle e_{ij}={1 \over {2}}(\beta _{ij}+\beta _{ij}^{r}),\qquad \omega _{ij}={1 \over {2}}(\beta _{ij}-\beta


id: electron-backscatter-diffraction-20260505-5
file: data/en.wikipedia.org/wiki/Electron_backscatter_diffraction-5.md
category: reference
title: Electron backscatter diffraction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_backscatter_diffraction
date_saved: 2026-05-05T10:04:21.164305+00:00
instance: kb-cron
parent: electron-backscatter-diffraction-20260505-0
summary:
=== The reference pattern problem === In HR-EBSD analysis, the lattice distortion field is calculated relative to a reference pattern or point (EBSP0) per grain in the map, and is dependent on the lattice distortion at the point. The lattice distortion field in each grain is measured with respect to this point; therefore, the absolute lattice distortion at the reference point (relative to the unstrained crystal) is excluded from the HR-EBSD elastic strain and rotation maps. This 'reference pattern problem' is similar to the 'd0 problem' in X-ray diffraction, and affects the nominal magnitude of HR-EBSD stress fields. However, selecting the reference pattern (EBSP0) plays a key role, as severely deformed EBSP0 adds phantom lattice distortions to the map values, thus, decreasing the measurement precision. The local lattice distortion at the EBSP0 influences the resultant HR-EBSD map, e.g., a reference pattern deformed in tension will directly reduce the HR-EBSD map tensile strain magnitude while indirectly influencing the other component magnitude and the strain's spatial distribution. Furthermore, the choice of EBSP0 slightly affects the GND density distribution and magnitude, and choosing a reference pattern with a higher GND density reduces the cross-correlation quality, changes the spatial distribution and induces more errors


id: electron-backscatter-diffraction-20260505-6
file: data/en.wikipedia.org/wiki/Electron_backscatter_diffraction-6.md
category: reference
title: Electron backscatter diffraction
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_backscatter_diffraction
date_saved: 2026-05-05T10:04:21.164305+00:00
instance: kb-cron
parent: electron-backscatter-diffraction-20260505-0
summary:
=== Integrated EBSD/EDS mapping === When simultaneous EDS/EBSD collection can be achieved, the capabilities of both techniques can be enhanced. There are applications where sample chemistry or phase cannot be differentiated via EDS alone because of similar composition, and structure cannot be solved with EBSD alone because of ambiguous structure solutions. To accomplish integrated mapping, the analysis area is scanned, and at each point, Hough peaks and EDS region-of-interest counts are stored. Positions of phases are determined in X-ray maps, and each element's measured EDS intensities are given in charts. The chemical intensity ranges are set for each phase to select the grains. All patterns are then re-indexed off-line. The recorded chemistry determines which phase/crystal-structure file is used to index each point. Each pattern is indexed by only one phase, and maps displaying distinguished phases are generated. The interaction volumes for EDS and EBSD are significantly different (on the order of micrometres compared to tens of nanometres), and the shape of these volumes using a highly tilted sample may have implications on algorithms for phase discrimination. EBSD, when used together with other in-SEM techniques such as cathodoluminescence (CL), wavelength dispersive X-ray spectroscopy (WDS) and/or EDS can provide a deeper insight


id: electron-beam-induced-current-20260505-0
file: data/en.wikipedia.org/wiki/Electron_beam-induced_current-0.md
category: reference
title: Electron beam-induced current
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_beam-induced_current
date_saved: 2026-05-05T10:04:22.337193+00:00
instance: kb-cron
parent: electron-beam-induced-current-20260505-0
summary:
Electron-beam-induced current (EBIC) is a semiconductor analysis technique performed in a scanning electron microscope (SEM) or scanning transmission electron microscope (STEM). It is most commonly used to identify buried junctions or defects in semiconductors, or to examine minority carrier properties. EBIC is similar to cathodoluminescence in that it depends on the creation of electron–hole pairs in the semiconductor sample by the microscope's electron beam. This technique is used in semiconductor failure analysis and solid-state physics. == Physics of the technique == If the semiconductor sample contains an internal electric field, as will be present in the depletion region at a p-n junction or Schottky junction, the electron–hole pairs will be separated by drift due to the electric field. If the p- and n-sides (or semiconductor and Schottky contact, in the case of a Schottky device) are connected through a picoammeter, a current will flow. EBIC is best understood by analogy: in a solar cell, photons of light fall on the entire cell, thus delivering energy and creating electron hole pairs, and cause a current to flow. In EBIC, energetic electrons take the role of the photons, causing the EBIC current to flow. However, because the electron beam of an SEM


id: electron-channelling-contrast-imaging-20260505-0
file: data/en.wikipedia.org/wiki/Electron_channelling_contrast_imaging-0.md
category: reference
title: Electron channelling contrast imaging
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_channelling_contrast_imaging
date_saved: 2026-05-05T10:04:23.537836+00:00
instance: kb-cron
parent: electron-channelling-contrast-imaging-20260505-0
summary:
Electron channelling contrast imaging (ECCI) is a scanning electron microscope (SEM) diffraction technique used in the study of defects in materials. These can be dislocations or stacking faults that are close to the surface of the sample, low angle grain boundaries or atomic steps. Unlike the use of transmission electron microscopy (TEM) for the investigation of dislocations, the ECCI approach has been called a rapid and non-destructive characterisation technique == Mechanism == The word channelling in ECCI, and, similarly, in electron channelling patterns refers to diffraction of the electron beam on its way in the sample. With enough spatial resolution, very small crystal imperfections would change the phase of the incident electron wave-function, and this, in turn, would be reflected in the backscattering probability, showing up as contrast (sharp change in backscattered intensity) close to a dislocation == Background == While we now talk about ECCI being a SEM technique, there was a significant gap of about thirty years between the prediction that defects ought to show up as contrast in the backscattered electron micrographs of the SEM and the development of ECCI as an accessible technique for the user of a standard SEM. In the meanwhile the field emission


id: electron-energy-loss-spectroscopy-20260505-0
file: data/en.wikipedia.org/wiki/Electron_energy_loss_spectroscopy-0.md
category: reference
title: Electron energy loss spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_energy_loss_spectroscopy
date_saved: 2026-05-05T10:04:24.739987+00:00
instance: kb-cron
parent: electron-energy-loss-spectroscopy-20260505-0
summary:
Electron energy loss spectroscopy (EELS) is a form of electron microscopy in which a material is exposed to a beam of electrons with a known, narrow range of kinetic energies. Some of the electrons will undergo inelastic scattering, which means that they lose energy and have their paths slightly and randomly deflected. The amount of energy loss can be measured via an electron spectrometer and interpreted in terms of what caused the energy loss. Inelastic interactions include phonon excitations, inter- and intra-band transitions, plasmon excitations, inner shell ionizations, and Cherenkov radiation. The inner-shell ionizations are particularly useful for detecting the elemental components of a material. For example, one might find that a larger-than-expected number of electrons comes through the material with 285 eV less energy than they had when they entered the material. This is approximately the amount of energy needed to remove an inner-shell electron from a carbon atom, which can be taken as evidence that there is a significant amount of carbon present in the sample. With some care, and looking at a wide range of energy losses, one can determine the types of atoms, and the numbers of atoms of each type, being struck by the beam.


id: electron-energy-loss-spectroscopy-20260505-1
file: data/en.wikipedia.org/wiki/Electron_energy_loss_spectroscopy-1.md
category: reference
title: Electron energy loss spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_energy_loss_spectroscopy
date_saved: 2026-05-05T10:04:24.739987+00:00
instance: kb-cron
parent: electron-energy-loss-spectroscopy-20260505-0
summary:
There are several basic flavors of EELS, primarily classified by the geometry and by the kinetic energy of the incident electrons (typically measured in kiloelectron-volts, or keV). Probably the most common today is transmission EELS, in which the kinetic energies are typically 100 to 300 keV and the incident electrons pass entirely through the material sample. Usually this occurs in a transmission electron microscope (TEM), although some dedicated systems exist which enable extreme resolution in terms of energy and momentum transfer at the expense of spatial resolution. This approach is especially promising in the regime of low-energy reflection and scanning electron microscope (SEM)-based EELS, in which the lower incident beam energy means that energy filtering of both the source and scattered electrons can be done in smaller form-factors. Other flavors include reflection EELS (including reflection high-energy electron energy-loss spectroscopy (RHEELS)), typically at 10 to 1 keV, and aloof EELS (sometimes called near-field EELS), in which the electron beam does not in fact strike the sample but instead interacts with it via the long-ranged Coulomb interaction. Aloof EELS is particularly sensitive to surface properties but is limited to very small energy losses such as those associated with surface plasmons or direct


id: electron-energy-loss-spectroscopy-20260505-2
file: data/en.wikipedia.org/wiki/Electron_energy_loss_spectroscopy-2.md
category: reference
title: Electron energy loss spectroscopy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_energy_loss_spectroscopy
date_saved: 2026-05-05T10:04:24.739987+00:00
instance: kb-cron
parent: electron-energy-loss-spectroscopy-20260505-0
summary:
== Thickness measurements == EELS allows quick and reliable measurement of local thickness in transmission electron microscopy. The most efficient procedure is the following: Measure the energy loss spectrum in the energy range about −5..200 eV (wider better). Such measurement is quick (milliseconds) and thus can be applied to materials normally unstable under electron beams. Analyse the spectrum: (i) extract zero-loss peak (ZLP) using standard routines; (ii) calculate integrals under the ZLP (I0) and under the whole spectrum (I). The thickness t is calculated as mfp*ln(I/I0). Here mfp is the mean free path of electron inelastic scattering, which has been tabulated for most elemental solids and oxides. The spatial resolution of this procedure is limited by the plasmon localization and is about 1 nm, meaning that spatial thickness maps can be measured in scanning transmission electron microscopy with ~1 nm resolution. == Pressure measurements == The intensity and position of low-energy EELS peaks are affected by pressure. This fact allows mapping local pressure with ~1 nm spatial resolution. Peak shift method is reliable and straightforward. The peak position is calibrated by independent (usually optical) measurement using a diamond anvil cell. However, the spectral resolution of most EEL spectrometers (0.3-2 eV,


id: electron-ionization-20260505-0
file: data/en.wikipedia.org/wiki/Electron_ionization-0.md
category: reference
title: Electron ionization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_ionization
date_saved: 2026-05-05T10:04:25.973339+00:00
instance: kb-cron
parent: electron-ionization-20260505-0
summary:
Electron ionization (EI, formerly known as electron impact ionization and electron bombardment ionization) is an ionization method in which energetic electrons interact with solid or gas phase atoms or molecules to produce ions. EI was one of the first ionization techniques developed for mass spectrometry. However, this method is still a popular ionization technique. This technique is considered a hard (high fragmentation) ionization method, since it uses highly energetic electrons to produce ions. This leads to extensive fragmentation, which can be helpful for structure determination of unknown compounds. EI is the most useful for organic compounds which have a molecular weight below 600 amu. Also, several other thermally stable and volatile compounds in solid, liquid and gas states can be detected with the use of this technique when coupled with various separation methods. == History == Electron ionization was first described in 1918 by Canadian-American Physicist Arthur J. Dempster in the article of "A new method of positive ray analysis." It was the first modern mass spectrometer and used positive rays to determine the ratio of the mass to charge of various constituents. In this method, the ion source used an electron beam directed at a solid surface. The anode


id: electron-ionization-20260505-1
file: data/en.wikipedia.org/wiki/Electron_ionization-1.md
category: reference
title: Electron ionization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_ionization
date_saved: 2026-05-05T10:04:25.973339+00:00
instance: kb-cron
parent: electron-ionization-20260505-0
summary:
A schematic diagram of instrumentation which can be used for electron ionization is shown to the right. The ion source block is made out of metal. As the electron source, the cathode, which can be a thin filament of tungsten or rhenium wire, is inserted through a slit to the source block. Then it is heated up to an incandescent temperature to emit electrons. A potential of 70 V is applied between the cathode and source block to accelerate them to 70 eV kinetic energy to produce positive ions. The potential of the anode (electron trap) is slightly positive and it is placed on the outside of the ionization chamber, directly opposite to the cathode. The unused electrons are collected by this electron trap. The sample is introduced through the sample hole. To increase the ionization process, a weak magnetic field is applied parallel to the direction of the electrons' travel. Because of this, electrons travel in a narrow helical path, which increases their path length. The positive ions that are generated are accelerated by the repeller electrode into the accelerating region through the slit in the source block. By applying a potential to the ion source and maintaining the


id: electron-ionization-20260505-2
file: data/en.wikipedia.org/wiki/Electron_ionization-2.md
category: reference
title: Electron ionization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_ionization
date_saved: 2026-05-05T10:04:25.973339+00:00
instance: kb-cron
parent: electron-ionization-20260505-0
summary:
==== Analysis of biological fluids ==== The GC-EI-MS can be incorporated for the analysis of biological fluids for several applications. One example is the determination of thirteen synthetic pyrethroid insecticide molecules and their stereoisomers in whole blood. This investigation used a new rapid and sensitive electron ionization-gas chromatography–mass spectrometry method in selective ion monitoring mode (SIM) with a single injection of the sample. All the pyrethroid residues were separated by using a GC-MS operated in electron ionization mode and quantified in selective ion monitoring mode. The detection of specific residues in blood is a difficult task due to their very low concentration since as soon as they enter the body most of the chemicals may get excreted. However, this method detected the residues of different pyrethroids down to the level 0.05–2 ng/ml. The detection of this insecticide in blood is very important since an ultra-small quantity in the body is enough to be harmful to human health, especially in children. This method is a very simple, rapid technique and therefore can be adopted without any matrix interferences. The selective ion monitoring mode provides detection sensitivity up to 0.05 ng/ml. Another application is in protein turnover studies using GC-EI-MS. This measures


id: electron-ionization-20260505-3
file: data/en.wikipedia.org/wiki/Electron_ionization-3.md
category: reference
title: Electron ionization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_ionization
date_saved: 2026-05-05T10:04:25.973339+00:00
instance: kb-cron
parent: electron-ionization-20260505-0
summary:
=== Fourier transform ion cyclotron resonance mass spectrometry === FT- ICR EI - MS can be used for analysis of three vacuum gas oil (VGO) distillation fractions in 295-319 °C, 319-456 °C and 456-543 °C. In this method, EI at 10 eV allows soft ionization of aromatic compounds in the vacuum gas oil range. The compositional variations at the molecular level were determined from the elemental composition assignment. Ultra-high resolving power, small sample size, high reproducibility and mass accuracy (<0.4ppm) are the special features in this method. The major product was aromatic hydrocarbons in all three samples. In addition, many sulfur-, nitrogen-, and oxygen-containing compounds were directly observed when the concentration of this heteroatomic species increased with the boiling point. Using data analysis it gave the information about compound types (rings plus double bonds), their carbon number distributions for hydrocarbon and heteroatomic compounds in the distillation fractions, increasing average molecular weight (or carbon number distribution) and aromaticity with increasing boiling temperature of the petroleum fractions. === Ion trap mass spectrometry === Ion trap EI MS can be incorporated for the identification and quantitation of nonylphenol polyethoxylate (NPEO) residues and their degradation products such as nonylphenol polyethoxy carboxylates and carboxyalkylphenol ethoxy


id: electron-paramagnetic-resonance-20260505-0
file: data/en.wikipedia.org/wiki/Electron_paramagnetic_resonance-0.md
category: reference
title: Electron paramagnetic resonance
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_paramagnetic_resonance
date_saved: 2026-05-05T10:04:27.171248+00:00
instance: kb-cron
parent: electron-paramagnetic-resonance-20260505-0
summary:
Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that have unpaired electrons. The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but the spins excited are those of the electrons instead of the atomic nuclei. EPR spectroscopy is useful for analyzing metal ions and organic radicals (compounds with unpaired electrons). The technique reveals some structural information but often simply provides a characteristic "finger print". The measurement requires a large magnet into which the sample is placed. Signals are detected using microwaves. In contrast to NMR and infrared (IR) spectroscopy, EPR spectroscopy is less common. For a given sample, some of the parameters of interest are g-values (analogous to chemical shift), anisotropy (asymmetry), hyperfine coupling constants (analogous to coupling constant J), and relaxation times. == History == EPR was first observed in Kazan State University by Soviet physicist Yevgeny Zavoisky in 1944, and was developed independently at the same time by Brebis Bleaney at the University of Oxford. == Theory == Every electron has a magnetic moment and spin quantum number s = 1 2 {\displaystyle s={\tfrac {1}{2}}} , with magnetic components m s = + 1 2


id: electron-paramagnetic-resonance-20260505-1
file: data/en.wikipedia.org/wiki/Electron_paramagnetic_resonance-1.md
category: reference
title: Electron paramagnetic resonance
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electron_paramagnetic_resonance
date_saved: 2026-05-05T10:04:27.171248+00:00
instance: kb-cron
parent: electron-paramagnetic-resonance-20260505-0
summary:
=== Maxwell–Boltzmann distribution === In practice, EPR samples consist of collections of many paramagnetic species, and not single isolated paramagnetic centers. If the population of radicals is in thermodynamic equilibrium, its statistical distribution is described by the Boltzmann distribution: n upper n lower = exp ⁡ ( − E upper − E lower k T ) = exp ⁡ ( − Δ E k T ) = exp ⁡ ( − ϵ k T ) = exp ⁡ ( − h ν k T ) {\displaystyle {\frac {n_{\text{upper}}}{n_{\text{lower}}}}=\exp {\left(-{\frac {E_{\text{upper}}-E_{\text{lower}}}{kT}}\right)}=\exp {\left(-{\frac {\Delta E}{kT}}\right)}=\exp {\left(-{\frac {\epsilon }{kT}}\right)}=\exp {\left(-{\frac {h\nu }{kT}}\right)}} where n upper {\displaystyle n_{\text{upper}}} is the number of paramagnetic centers occupying the upper energy state, k {\displaystyle k} is the Boltzmann constant, and T {\displaystyle T} is the thermodynamic temperature. At 298 K, X-band microwave frequencies ( ν {\displaystyle \nu } ≈ 9.75 GHz) give n upper / n lower {\displaystyle n_{\text{upper}}/n_{\text{lower}}} ≈ 0.998, meaning that the upper energy level has a slightly smaller population than the lower one. Therefore, transitions from the lower to the higher level are more probable than the reverse, which is why there is a net absorption of energy. The sensitivity of the EPR method


