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Topic Review

Anthroponotic Disease

Reverse zoonosis, also known as zooanthroponosis, and sometimes anthroponosis (Greek zoon "animal", anthropos "man", nosos "disease"), refers to pathogens reservoired in humans that are capable of being transmitted to other non-human animals.

9.0K
28 Oct 2022

Topic Review

Transwiki: Multiregional Origin of Modern Humans

The multiregional hypothesis is a scientific model that provides an explanation for the pattern of human evolution. The hypothesis holds that humans first arose near the beginning of the Pleistocene two million years ago and subsequent human evolution has been within a single, continuous human species. This species encompasses archaic human forms such as Homo erectus and Neanderthals as well as modern forms, and evolved worldwide to the diverse populations of modern Homo sapiens sapiens. The theory contends that humans evolve through a combination of adaptation within various regions of the world and gene flow between those regions. Proponents of multiregional origin point to fossil and genomic data and continuity of archaeological cultures as support for their hypothesis. The primary alternative hypothesis is recent African origin of modern humans, which contends that modern humans arose in Africa around 100-200,000 years ago, moving out of Africa around 50-60,000 years ago to replace archaic human forms without interbreeding.

9.0K
11 Nov 2022

Topic Review

The Nag missile (IAST: Nāga; en: Cobra), also called "Prospina" for the land-attack version, is an India n third-generation, all-weather, fire-and-forget, lock-on after launch, anti-tank guided missile (ATGM) with an operational range of 500 m to 20 km. It has a single-shot hit probability of 90% and a ten-year, maintenance-free shelf life. The Nag has five variants under development: a land version, for a mast-mounted system; the helicopter-launched Nag (HELINA) also known as Dhruvastra; a "man-portable" version (MPATGM); an air-launched version which will replace the current imaging infra-red (IIR) to millimetric-wave (mmW) active radar homing seeker; and the Nag Missile Carrier (NAMICA) "tank buster", which is a modified BMP-2 Infantry Fighting Vehicle (IFV) produced under license in India by Ordnance Factory Medak (OFMK). Development of the Nag is part of the Integrated Guided Missile Development Program (IGMDP), run by Defence Research and Development Organisation (DRDO). It is manufactured by Bharat Dynamics Limited (BDL). India's Ministry of Defence (MoD) announced on 19 July 2019 that the missile was ready for production. The Defence Research and Development Organization (DRDO) successfully completed the final trial of Nag anti-tank missile using a live warhead on a dud tank at Pokhran army ranges at 6.45 am on Oct 21, 2020.

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09 Oct 2022

Topic Review

Lists of Mathematics Topics

This article itemizes the various lists of mathematics topics. Some of these lists link to hundreds of articles; some link only to a few. The template to the right includes links to alphabetical lists of all mathematical articles. This article brings together the same content organized in a manner better suited for browsing. The purpose of this list is not similar to that of the Mathematics Subject Classification formulated by the American Mathematical Society. Many mathematics journals ask authors of research papers and expository articles to list subject codes from the Mathematics Subject Classification in their papers. The subject codes so listed are used by the two major reviewing databases, Mathematical Reviews and Zentralblatt MATH. This list has some items that would not fit in such a classification, such as list of exponential topics and list of factorial and binomial topics, which may surprise the reader with the diversity of their coverage.

9.0K
19 Oct 2022

Topic Review Peer Reviewed

Challenges for Nanotechnology

The term “Nanotechnology” describes a large field of scientific and technical activities dealing with objects and technical components with small dimensions. Typically, bodies that are in–at least–two dimensions smaller than 0.1 µm are regarded as “nanobjects”. By this definition, a lot of advanced materials, as well as the advanced electronic devices, are objects of nanotechnology. In addition, many aspects of molecular biotechnology as well as macromolecular and supermolecular chemistry and nanoparticle techniques are summarized under “nanotechnology”. Despite this size-oriented definition, nanotechnology is dealing with physics and chemistry as well as with the realization of technical functions in the area between very small bodies and single particles and molecules. This includes the shift from classical physics into the quantum world of small molecules and low numbers or single elementary particles. Besides the already established fields of nanotechnology, there is a big expectation about technical progress and solution to essential economic, medical, and ecological problems by means of nanotechnology. Nanotechnology can only meet these expectations if fundamental progress behind the recent state of the art can be achieved. Therefore, very important challenges for nanotechnology are discussed here.

9.0K
13 Apr 2022

Topic Review Peer Reviewed

Affective Economy: A Theoretical Outline

The affective economy is a concept that emerged within the field of social sciences, focusing on the interplay between emotions, affects, and economic processes. It explores how emotions and affective experiences shape economic practices, consumption patterns, and the production of goods and services. In the affective economy framework, emotions are seen as not merely individual but deeply embedded in social and political contexts, shaping and being shaped by social structures and power dynamics. The affective economy emphasizes how emotions circulate and contribute to the construction and maintenance of social orders, impacting economic actions. It acknowledges the profound impact of emotions and affects on economic behavior. Thus, this concept sheds light on the intricate relationship between emotions and economic processes, demonstrating how affective experiences influence consumption, production, labor, financial decisions, and the overall dynamics of the market economy. It emphasizes the need for a more nuanced understanding of human behavior in economic contexts, recognizing the significance of emotions and affective responses as integral components of economic activities. This concept is connected to notions of dwelling, topophilia, and affective atmospheres, providing insights into the complexities of economic transactions in diverse cultural contexts.

9.0K
28 Aug 2023

Topic Review

Yan Tan Tethera

Yan Tan Tethera is a sheep-counting rhyme/system traditionally used by shepherds in Northern England and earlier in some other parts of Britain. Until the Industrial Revolution, the use of traditional number systems was common among shepherds, especially in the fells of the Lake District. The Yan Tan Tethera system was also used for counting stitches in knitting. The words derive from a Brythonic Celtic language. Though most of these number systems fell out of use by 1910, some are still in use. The word yan or yen for "one" in some northern English dialects generally represents a regular development in Northern English in which the Old English long vowel /ɑː/ was broken into /ie/, /ia/ and so on. This explains the shift to yan and ane from the Old English ān, which is itself derived from the Proto-Germanic *ainaz. Another example of this development is the Northern English word for "home", hame, which has forms such as hyem, yem and yam all deriving from the Old English hām.

8.9K
20 Nov 2022

Topic Review

Thermoregulation Strategies in Domestic Animals

Animals adopt several strategies to regulate their body temperature by promoting heat loss or gain in hot and cold environments, respectively. This mechanism of heat loss or production is performed in thermal windows. A thermal window is a structure where many blood capillaries facilitate thermal exchange in this region. The presence of feathers, hair, or glabrous (hairless) skin and their structural characteristics greatly influence each species’ capacity to maintain thermal comfort. This factor needs to be considered when implementing new monitoring or measuring techniques such as infrared thermography since interpretations may vary due to the presence or absence of these structures. It is essential to recognize the effects of glabrous skin, hair, and feathers on thermoregulation to identify species-specific thermal windows that allow accurate evaluations of the thermal state of domestic animals.

8.9K
19 Apr 2022

Topic Review

Vegetation Optical Depth

The vegetation optical depth (VOD) parameterizes the extinction (attenuation & scattering) effects due to the vegetation affecting the microwave radiations propagating through the vegetation canopy. It is retrieved from both passive and active microwave remotely sensed observations. It is related almost linearly to the vegetation water content and indirectly to vegetation water status and biomass. It has been retrieved from several satellites operating at different frequencies and provides a long-term record of the vegetation dynamics over land surfaces since 1978. VOD is complementary to classically used vegetation indices derived from multi-spectral images but it is less affected by sun illumination and atmospheric effects than optical vegetation indices.

8.9K
27 Nov 2020

Topic Review

Liberal Socialism

Liberal socialism is a socialist political philosophy that incorporates liberal principles. Liberal socialism does not have the goal of completely abolishing capitalism and replacing it with socialism, but it instead supports a mixed economy that includes both private property and social ownership in capital goods. Although liberal socialism unequivocally favors a mixed market economy, it identifies legalistic and artificial monopolies to be the fault of capitalism and opposes an entirely unregulated economy. It considers both liberty and equality to be compatible and mutually dependent on each other. Principles that can be described as liberal socialist are based on the works of philosophers such as John Stuart Mill, Eduard Bernstein, John Dewey, Carlo Rosselli, Norberto Bobbio, Chantal Mouffe and Karl Polanyi. Other important liberal socialist figures include Guido Calogero, Piero Gobetti, Leonard Hobhouse, John Maynard Keynes and R. H. Tawney. To Polanyi, liberal socialism's goal was overcoming exploitative aspects of capitalism by expropriation of landlords and opening to all the opportunity to own land. Liberal socialism has been particularly prominent in British and Italian politics. Liberal socialism’s seminal ideas can be traced to John Stuart Mill, who theorised that capitalist societies should experience a gradual process of socialisation through worker-controlled enterprises, coexisting with private enterprises. Mill rejected centralised models of socialism that could discourage competition and creativity, but he argued that representation is essential in a free government and democracy could not subsist if economic opportunities were not well distributed, therefore conceiving democracy not just as form of representative government, but as an entire social organisation.

8.9K
01 Dec 2022

Topic Review

α- and β-Pinene

α- and β-pinene are well-known representatives of the monoterpenes group, and are found in many plants’ essential oils. A wide range of pharmacological activities have been reported, including antibiotic resistance modulation, anticoagulant, antitumor, antimicrobial, antimalarial, antioxidant, anti-inflammatory, anti-Leishmania, and analgesic effects.

8.9K
23 Jul 2021

Topic Review

Partition Problem

In number theory and computer science, the partition problem, or number partitioning, is the task of deciding whether a given multiset S of positive integers can be partitioned into two subsets S1 and S2 such that the sum of the numbers in S1 equals the sum of the numbers in S2. Although the partition problem is NP-complete, there is a pseudo-polynomial time dynamic programming solution, and there are heuristics that solve the problem in many instances, either optimally or approximately. For this reason, it has been called "the easiest hard problem". There is an optimization version of the partition problem, which is to partition the multiset S into two subsets S1, S2 such that the difference between the sum of elements in S1 and the sum of elements in S2 is minimized. The optimization version is NP-hard, but can be solved efficiently in practice.

8.9K
10 Oct 2022

Topic Review

A shopping cart (American English) or trolley (British English), also known by a variety of other names, is a cart supplied by a shop, especially supermarkets, for use by customers inside the shop for transport of merchandise to the checkout counter during shopping. In many cases customers can then also use the cart to transport their purchased goods to their vehicles, but some carts are designed to prevent them from leaving the shop. In many places in the United States and the United Kingdom , customers are allowed to leave the carts in designated areas within the parking lot, and store personnel will return the carts to the storage area. In many continental European premises, however, coin- (or token-) operated locking mechanisms are provided to encourage shoppers to return the carts to the correct location after use. Studies have shown that it is advisable for shoppers to sanitize the handles and basket areas prior to handling them or filling them with groceries due to high levels of bacteria that typically live on shopping carts. This is due to the carts having a high level of exposure to the skin flora of previous users.

8.9K
22 Nov 2022

Topic Review

A spark gap consists of an arrangement of two conducting electrodes separated by a gap usually filled with a gas such as air, designed to allow an electric spark to pass between the conductors. When the potential difference between the conductors exceeds the breakdown voltage of the gas within the gap, a spark forms, ionizing the gas and drastically reducing its electrical resistance. An electric current then flows until the path of ionized gas is broken or the current reduces below a minimum value called the "holding current". This usually happens when the voltage drops, but in some cases occurs when the heated gas rises, stretching out and then breaking the filament of ionized gas. Usually, the action of ionizing the gas is violent and disruptive, often leading to sound (ranging from a snap for a spark plug to thunder for a lightning discharge), light and heat. Spark gaps were used historically in early electrical equipment, such as spark gap radio transmitters, electrostatic machines, and X-ray machines. Their most widespread use today is in spark plugs to ignite the fuel in internal combustion engines, but they are also used in lightning arresters and other devices to protect electrical equipment from high-voltage transients.

8.9K
08 Oct 2022

Topic Review

Permeability (Earth Sciences)

Permeability in fluid mechanics and the earth sciences (commonly symbolized as κ, or k) is a measure of the ability of a porous material (often, a rock or an unconsolidated material) to allow fluids to pass through it. The permeability of a medium is related to the porosity, but also to the shapes of the pores in the medium and their level of connectedness.

8.9K
25 Oct 2022

Topic Review

A holobiont is an assemblage of a host and the many other species living in or around it, which together form a discrete ecological unit, though there is controversy over this discreteness. The components of a holobiont are individual species or bionts, while the combined genome of all bionts is the hologenome. The concept of the holobiont was initially defined by Dr. Lynn Margulis in her 1991 book Symbiosis as a Source of Evolutionary Innovation, though the concept has subsequently evolved since the original definition. Holobionts include the host, virome, microbiome, and other members, all of which contribute in some way to the function of the whole. Well-studied holobionts include reef-building corals and humans.

8.9K
14 Oct 2022

Topic Review

Prohibited Degree of Kinship

In law, a prohibited degree of kinship refers to a degree of consanguinity (blood relatedness) and sometimes affinity (relation by marriage or sexual relationship) between persons that results in certain actions between them being illegal. Two major examples of prohibited degrees are found in incest and nepotism. Incest refers to sexual relations and marriage between closely related individuals; nepotism is the preference of blood-relations in the distribution of a rank or office. An incest taboo against sexual relations between parent and child or two full-blooded siblings is a cultural universal. Taboos against sexual relations between individuals of other close degrees of relationship vary, but stigmatization of unions with full siblings and with direct descendants are widespread.

8.9K
19 Oct 2022

Topic Review Peer Reviewed

Road Markings and Signs in Road Safety

Due to the dynamic nature and complexity of road traffic, road safety is one of the most demanding social challenges. Therefore, contemporary road safety strategies incorporate a multidisciplinary and comprehensive approaches to address this problem and improve the safety of each individual element, i.e., the human, vehicle, and road. Traffic control devices are an important part of road infrastructure, among which road markings and road signs play a significant role. In general, road markings and signs represent basic means of communication between the road authorities and road users and, as such, provide road users with necessary information about the rules, warnings, obligations, and other information related to the upcoming situations and road alignment. The aim of this entry is to briefly present the main functions and characteristics of road markings and signs, and their role in road safety. In addition, practical issues and future trends and directions regarding road markings and signs are discussed.

8.9K
21 Oct 2022

Topic Review

Peer pressure is the direct or indirect influence on people of peers, members of social groups with similar interests, experiences, or social statuses. Members of a peer group are more likely to influence a person's beliefs and behavior. A group or individual may be encouraged and want to follow their peers by changing their attitudes, values or behaviors to conform to those of the influencing group or individual. For the individual affected by peer pressure, this can result in either a positive or negative effect or both. Social groups include both membership groups in which individuals hold "formal" membership (e.g. political parties, trade unions, schools) and cliques in which membership is less clearly defined. However, a person does not need to be a member or be seeking membership of a group to be affected by peer pressure. Research suggests that organizations as well as individuals are susceptible to peer pressure. For example, a large company may be influenced by other firms in their industry or from headquarters. Peer pressure can affect individuals of all ethnicities, genders and ages. Researchers have frequently studied the effects of peer pressure on children and on adolescents, and in popular discourse the term "peer pressure" is used most often with reference to those age-groups. For children, the themes most commonly studied are their abilities for independent decision-making. For adolescents, peer pressure's relationships to sexual intercourse and substance abuse have been significantly researched. Peer pressure can be experienced through both face-to-face interaction and through digital interaction. Social media offers opportunities for adolescents and adults alike to instill and/or experience pressure every day. Studies of social networks examine connections between members of social groups, including their use of social media, to better understand mechanisms such as information sharing and peer sanctioning. Sanctions can range from subtle glances that suggest disapproval, to threats and physical violence. Peer sanctioning may enhance either positive or negative behaviors. Whether peer sanctioning will have an effect depends in part on members' expectations that possible sanctions will actually be applied. It can also depend on a person's position in a social network. Those who are more central in a social network seem more likely to be cooperative, perhaps as a result of how networks form. However, this goes both ways and so they are also more likely to participate in negative behaviors. This may be caused by the repeated social pressures they experience in their networks.

8.9K
07 Nov 2022

Topic Review

Proton–Proton Chain

The proton–proton chain, also commonly referred to as the p-p chain, is one of two known sets of nuclear fusion reactions by which stars convert hydrogen to helium. It dominates in stars with masses less than or equal to that of the Sun, whereas the CNO cycle, the other known reaction, is suggested by theoretical models to dominate in stars with masses greater than about 1.3 times that of the Sun. In general, proton–proton fusion can occur only if the kinetic energy (i.e. temperature) of the protons is high enough to overcome their mutual electrostatic repulsion. In the Sun, deuterium-producing events are rare. Diprotons are the much more common result of proton–proton reactions within the star, and diprotons almost immediately decay back into two protons. Since the conversion of hydrogen to helium is slow, the complete conversion of the hydrogen initially in the core of the Sun is calculated to take more than ten billion years. Although sometimes called the "proton–proton chain reaction", it is not a chain reaction in the normal sense. In most nuclear reactions, a chain reaction designates a reaction that produces a product, such as neutrons given off during fission, that quickly induces another such reaction. The proton-proton chain is, like a decay chain, a series of reactions. The product of one reaction is the starting material of the next reaction. There are two main chains leading from Hydrogen to Helium in the Sun. One chain has five reactions, the other chain has six.

8.9K
10 Nov 2022

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