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π Extracorporeal Membrane Oxygenation
Extracorporeal membrane oxygenation (ECMO), also known as extracorporeal life support (ECLS), is an extracorporeal technique of providing prolonged cardiac and respiratory support to persons whose heart and lungs are unable to provide an adequate amount of gas exchange or perfusion to sustain life. The technology for ECMO is largely derived from cardiopulmonary bypass, which provides shorter-term support with arrested native circulation. The device used is a membrane oxygenator, also known as an artificial lung.
ECMO works by temporarily drawing blood from the body to allow artificial oxygenation of the red blood cells and removal of carbon dioxide. Generally, it is used either post-cardiopulmonary bypass or in late-stage treatment of a person with profound heart and/or lung failure, although it is now seeing use as a treatment for cardiac arrest in certain centers, allowing treatment of the underlying cause of arrest while circulation and oxygenation are supported. ECMO is also used to support patients with the acute viral pneumonia associated with COVID-19 in cases where artificial ventilation alone is not sufficient to sustain blood oxygenation levels.
π OODA Loop
The OODA loop is the cycle observeβorientβdecideβact, developed by military strategist and United States Air Force Colonel John Boyd. Boyd applied the concept to the combat operations process, often at the operational level during military campaigns. It is now also often applied to understand commercial operations and learning processes. The approach explains how agility can overcome raw power in dealing with human opponents. It is especially applicable to cyber security and cyberwarfare.
The OODA loop has become an important concept in litigation, business, law enforcement, management education, and military strategy. According to Boyd, decision-making occurs in a recurring cycle of observeβorientβdecideβact. An entity (whether an individual or an organization) that can process this cycle quickly, observing and reacting to unfolding events more rapidly than an opponent, can thereby "get inside" the opponent's decision cycle and gain the advantage.
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- "OODA Loop" | 2023-02-21 | 155 Upvotes 63 Comments
π Pi Calculus
In theoretical computer science, the Ο-calculus (or pi-calculus) is a process calculus. The Ο-calculus allows channel names to be communicated along the channels themselves, and in this way it is able to describe concurrent computations whose network configuration may change during the computation.
The Ο-calculus is simple, it has few terms and so is a small, yet expressive language (see #Syntax). Functional programs can be encoded into the Ο-calculus, and the encoding emphasises the dialogue nature of computation, drawing connections with game semantics. Extensions of the Ο-calculus, such as the spi calculus and applied Ο, have been successful in reasoning about cryptographic protocols. Beside the original use in describing concurrent systems, the Ο-calculus has also been used to reason about business processes and molecular biology.
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- "Pi Calculus" | 2013-12-15 | 12 Upvotes 7 Comments
π Finite Element Method
The finite element method (FEM) is the most widely used method for solving problems of engineering and mathematical models. Typical problem areas of interest include the traditional fields of structural analysis, heat transfer, fluid flow, mass transport, and electromagnetic potential. The FEM is a particular numerical method for solving partial differential equations in two or three space variables (i.e., some boundary value problems). To solve a problem, the FEM subdivides a large system into smaller, simpler parts that are called finite elements. This is achieved by a particular space discretisation in the space dimensions, which is implemented by the construction of a mesh of the object: the numerical domain for the solution, which has a finite number of points. The finite element method formulation of a boundary value problem finally results in a system of algebraic equations. The method approximates the unknown function over the domain. The simple equations that model these finite elements are then assembled into a larger system of equations that models the entire problem. The FEM then uses variational methods from the calculus of variations to approximate a solution by minimizing an associated error function.
Studying or analyzing a phenomenon with FEM is often referred to as finite element analysis (FEA).
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- "Finite Element Method" | 2020-02-17 | 75 Upvotes 44 Comments
π Agbogbloshie, the world's largest e-waste dump
Agbogbloshie is a nickname of a commercial district on the Korle Lagoon of the Odaw River, near the center of Accra, Ghana's capital city. Near the slum called "Old Fadama", the Agbogbloshie site became known as a destination for externally generated automobile and electronic scrap collected from mostly the western world. It was alleged to be at the center of a legal and illegal exportation network for the environmental dumping of electronic waste (e-waste) from industrialized nations. The Basel Action Network, a small NGO based in Seattle, has referred to Agbogbloshie as a "digital dumping ground", where they allege millions of tons of e-waste are processed each year.
However, repeated international studies have failed to confirm the allegations, which have been labelled an "e-waste hoax" by international reuse advocate WR3A. The most exhaustive study of the trade in used electronics in Nigeria, funded by UNEP and Basel Convention, revealed that from 540 000 tonnes of informally processed waste electronics, 52% of the material was recovered.
According to statistics from the World Bank, in large cities like Accra and Lagos the majority of households have owned televisions and computers for decades. The UN Report "Where are WEEE in Africa" (2012) disclosed that the majority of used electronics found in African dumps had not in fact been recently imported as scrap, but originated from these African cities. Agbogbloshie is situated on the banks of the Korle Lagoon, northwest of Accra's Central Business District. Roughly 40,000 Ghanaians inhabit the area, most of whom are migrants from rural areas. Due to its harsh living conditions and rampant crime, the area is nicknamed "Sodom and Gomorrah".
The Basel Convention prevents the transfrontier shipment of hazardous waste from developed to less developed countries. However, the Convention specifically allows export for reuse and repair under Annex Ix, B1110. While numerous international press reports have made reference to allegations that the majority of exports to Ghana are dumped, research by the US International Trade Commission found little evidence of unprocessed e-waste being shipped to Africa from the United States, a finding corroborated by the United Nations Environment Programme, MIT, Memorial University, Arizona State University, and other research. In 2013, the original source of the allegation blaming foreign dumping for the material found in Agbogbloshie recanted, or rather stated it had never made the claim that 80% of US e-waste is exported.
Whether domestically generated by residents of Ghana or imported, concern remains over methods of waste processing - especially burning - which emit toxic chemicals into the air, land and water. Exposure is especially hazardous to children, as these toxins are known to inhibit the development of the reproductive system, the nervous system, and especially the brain. Concerns about human health and the environment of Agbogbloshie continue to be raised as the area remains heavily polluted. In the 2000s, the Ghanaian government, with new funding and loans, implemented the Korle Lagoon Ecological Restoration Project (KLERP), an environmental remediation and restoration project that will address the pollution problem by dredging the lagoon and Odaw canal to improve drainage and flooding into the ocean.
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- "Agbogbloshie, the world's largest e-waste dump" | 2015-03-03 | 107 Upvotes 51 Comments
π Frog galvanoscope
The frog galvanoscope was a sensitive electrical instrument used to detect voltage in the late eighteenth and nineteenth centuries. It consists of skinned frog's leg with electrical connections to a nerve. The instrument was invented by Luigi Galvani and improved by Carlo Matteucci.
The frog galvanoscope, and other experiments with frogs played a part in the dispute between Galvani and Alessandro Volta over the nature of electricity. The instrument is extremely sensitive and continued to be used well into the nineteenth century, even after electromechanical meters came into use.
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- "Frog Galvanoscope" | 2023-08-22 | 67 Upvotes 16 Comments
π Shotgun clause
A shotgun clause (or Texas Shootout Clause) is a term of art, rather than a legal term. It is a specific type of exit provision that may be included in a shareholders' agreement, and may often be referred to as a buy-sell agreement. The shotgun clause allows a shareholder to offer a specific price per share for the other shareholder(s)' shares; the other shareholder(s) must then either accept the offer or buy the offering shareholder's shares at that price per share.
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- "Shotgun clause" | 2010-01-19 | 24 Upvotes 6 Comments
π List of obsolete occupations
This is a list of obsolete occupations. To be included in this list an occupation must be completely, or to a great extent, obsolete. For example, there are still a few lamplighters retained for ceremonial or tourist purposes, but in the main the occupation is now obsolete. Similarly, there are still some manual switchboard operators and elevator operators which are required for historic equipment or security reasons, but these are now considered to be obsolete occupations. Occupations which appear to be obsolete in industrialized countries may still be carried out commercially in other parts of the world, for example charcoal burner.
To be included in this list an obsolete occupation should in the past have employed significant numbers of workers (hundreds or thousands as evidenced by, for example, census data). Some rare occupations are included in this list, but only if they have notable practitioners, for example alchemist or phrenologist.
Terms which describe groups of people carrying out a variety of roles, but which are not specific occupations, are excluded from this list even if they are obsolete, for example conquistador or retinue. Terms describing positions which have a modern equivalent, and are thus not obsolete occupations, are excluded from this list, for example a dragoman would now be termed a diplomat; similarly a cunning woman would now be termed a practitioner of folk medicine. Terms describing a state of being rather than an occupation are excluded, for example castrato. Specialist terms for an occupation, even if they are obsolete, are excluded, for example the numerous historic terms for cavalry and courtesan. Foreign language terms for existing occupations are excluded, for example korobeinik or LaukkuryssΓ€ which are types of peddler. All types of forced labour, such as slavery and penal labour are excluded from this list as they are not paid occupations.
Only occupations which are notable, well-defined, and adequately documented in secondary sources are included in this list.
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- "List of obsolete occupations" | 2026-01-27 | 35 Upvotes 3 Comments
π ISO 3103: an international standard for brewing tea
ISO 3103 is a standard published by the International Organization for Standardization (commonly referred to as ISO), specifying a standardized method for brewing tea, possibly sampled by the standardized methods described in ISO 1839. It was originally laid down in 1980 as BS 6008:1980 by the British Standards Institution, and a revision was published in December, 2019 as ISO/NP 3103. It was produced by ISO Technical Committee 34 (Food products), Sub-Committee 8 (Tea).
The abstract states the following:
The method consists in extracting of soluble substances in dried tea leaf, contained in a porcelain or earthenware pot, by means of freshly boiling water, pouring of the liquor into a white porcelain or earthenware bowl, examination of the organoleptic properties of the infused leaf, and of the liquor with or without milk, or both.
This standard is not meant to define the proper method for brewing tea intended for general consumption, but rather to document a tea brewing procedure where meaningful sensory comparisons can be made. An example of such a test would be a taste-test to establish which blend of teas to choose for a particular brand or basic label in order to maintain a consistent tasting brewed drink from harvest to harvest.
The work was the winner of the parodic Ig Nobel Prize for Literature in 1999.
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- "ISO Standard for Preparing Tea" | 2021-03-07 | 175 Upvotes 130 Comments
- "ISO 3103: an international standard for brewing tea" | 2008-01-06 | 10 Upvotes 7 Comments
π Law of Jante
The Law of Jante (Danish: Janteloven) is a code of conduct known in Nordic countries that characterizes not conforming, doing things out of the ordinary, or being overtly personally ambitious as unworthy and inappropriate. The attitudes were first formulated in the form of the ten rules of Jante Law by the Dano-Norwegian author Aksel Sandemose in his satirical novel A Fugitive Crosses His Tracks (En flyktning krysser sitt spor, 1933), but the actual attitudes themselves are older. Sandemose portrays the fictional small Danish town Jante, which he modelled upon his native town NykΓΈbing Mors in the 1930s, where nobody was anonymous, which is typical of all small towns and communities.
Used generally in colloquial speech in the Nordic countries as a sociological term to denote a social attitude of disapproval towards expressions of individuality and personal success, it emphasizes adherence to the collective.
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- "Law of Jante" | 2024-07-31 | 10 Upvotes 4 Comments
- "The Law of Jante" | 2023-11-19 | 12 Upvotes 1 Comments
- "Law of Jante" | 2023-05-23 | 13 Upvotes 2 Comments
- "Law of Jante" | 2017-09-30 | 87 Upvotes 61 Comments