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Topic Review
Permian–Triassic Extinction Event
The Permian–Triassic extinction event, also known as the P–Tr extinction, the P–T extinction, the End-Permian Extinction, and colloquially as the Great Dying, formed the boundary between the Permian and Triassic geologic periods, as well as between the Paleozoic and Mesozoic eras, approximately 252 million years ago. It is the Earth's most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It was the largest known mass extinction of insects. Some 57% of all biological families and 83% of all genera became extinct. There is evidence for one to three distinct pulses, or phases, of extinction. Potential causes for those pulses include one or more large meteor impact events, massive volcanic eruptions (such as the Siberian Traps), and climate change brought on by large releases of underwater methane or methane-producing microbes. The speed of the recovery from the extinction is disputed. Some scientists estimate that it took 10 million years (until the Middle Triassic), due both to the severity of the extinction and because grim conditions returned periodically for another 5 million years. However, studies in Bear Lake County, near Paris, Idaho, showed a relatively quick rebound in a localized Early Triassic marine ecosystem, taking around 2 million years to recover, suggesting that the impact of the extinction may have been felt less severely in some areas than others.
  • 7.6K
  • 11 Oct 2022
Topic Review
Pathogenic Bacteria
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract. The body is continually exposed to many species of bacteria, including beneficial commensals, which grow on the skin and mucous membranes, and saprophytes, which grow mainly in the soil and in decaying matter. The blood and tissue fluids contain nutrients sufficient to sustain the growth of many bacteria. The body has defence mechanisms that enable it to resist microbial invasion of its tissues and give it a natural immunity or innate resistance against many microorganisms. Pathogenic bacteria are specially adapted and endowed with mechanisms for overcoming the normal body defences, and can invade parts of the body, such as the blood, where bacteria are not normally found. Some pathogens invade only the surface epithelium, skin or mucous membrane, but many travel more deeply, spreading through the tissues and disseminating by the lymphatic and blood streams. In some rare cases a pathogenic microbe can infect an entirely healthy person, but infection usually occurs only if the body's defence mechanisms are damaged by some local trauma or an underlying debilitating disease, such as wounding, intoxication, chilling, fatigue, and malnutrition. In many cases, it is important to differentiate infection and colonization, which is when the bacteria are causing little or no harm. Caused by Mycobacterium tuberculosis bacteria, one of the diseases with the highest disease burden is tuberculosis, which killed 1.4 million people in 2019, mostly in sub-Saharan Africa. Pathogenic bacteria contribute to other globally important diseases, such as pneumonia, which can be caused by bacteria such as Streptococcus, Pneumococcus and Pseudomonas, and foodborne illnesses, which can be caused by bacteria such as Shigella, Campylobacter, and Salmonella. Pathogenic bacteria also cause infections such as tetanus, typhoid fever, diphtheria, syphilis, and leprosy. Pathogenic bacteria are also the cause of high infant mortality rates in developing countries. Most pathogenic bacteria can be grown in cultures and identified by Gram stain and other methods. Bacteria grown in this way are often tested to find which antibiotics will be an effective treatment for the infection. For hitherto unknown pathogens, Koch's postulates are the standard to establish a causative relationship between a microbe and a disease.
  • 7.6K
  • 07 Nov 2022
Topic Review
Spray Congealing Technology
Spray congealing is an emerging technology for the production of solid dispersion to enhance the bioavailability of poorly soluble drugs by using low-melting hydrophilic excipients. Since the '90s, spray congealing technology has been used to obtain microparticles (MPs) for controlled release, taste masking and stability enhancement of APIs. The main advantages are the absence of solvents and the possibility to obtain free-flowing MPs by a relatively inexpensive, simple and one step process. This entry focused on the application of spary congealing as an amerging technology for the production of solid dispersions to enhance the bioavailability of poorly water soluble drugs by using low-melting hydrophilic excipients.
  • 7.6K
  • 14 Dec 2021
Topic Review
Overview of 21st-Century Propaganda
Since the end of the 20th century, propaganda has evolved significantly. Today's propaganda is characterised by psych-ops and disinformation, whereas a few decades ago it was dominated by posters and simple films.
  • 7.6K
  • 08 Nov 2022
Topic Review
Aparigraha
In Hinduism and Jainism, aparigraha (Sanskrit: अपरिग्रह) is the virtue of non-possessiveness, non-grasping or non-greediness. Aparigrah is the opposite of parigrah, and refers to keeping the desire for possessions to what is necessary or important, depending on one's life stage and context. The precept of aparigraha is a self-restraint (temperance) from the type of greed and avarice where one's own material gain or happiness comes by hurting, killing or destroying other human beings, life forms or nature. Aparigraha is related to and in part a motivator of dāna (proper charity), both from giver's and receiver's perspective.
  • 7.6K
  • 13 Oct 2022
Topic Review
Sexual Fetishism
Sexual fetishism or erotic fetishism is a sexual fixation on a nonliving object or nongenital body part. The object of interest is called the fetish; the person who has a fetish for that object is a fetishist. A sexual fetish may be regarded as a non-pathological aid to sexual excitement, or as a mental disorder if it causes significant psychosocial distress for the person or has detrimental effects on important areas of their life. Sexual arousal from a particular body part can be further classified as partialism. While medical definitions restrict the term sexual fetishism to objects or body parts, fetish can, in common discourse, also refer to sexual interest in specific activities.
  • 7.6K
  • 14 Oct 2022
Topic Review
Short-Chain Fatty Acids
The relationship between diet and the diversity and function of the intestinal microbiome and its importance for human health is currently the subject of many studies. The type and proportion of microorganisms found in the intestines can determine the energy balance of the host. Intestinal microorganisms perform many important functions, one of which is participation in metabolic processes, e.g., in the production of short-chain fatty acids—SCFAs (also called volatile fatty acids). These acids represent the main carbon flow from the diet to the host microbiome. Maintaining intestinal balance is necessary to maintain the host’s normal health and prevent many diseases. The results of many studies confirm the beneficial effect of probiotic microorganisms on the balance of the intestinal microbiome and produced metabolites, including SCFAs. The aim of this review is to summarize what is known on the effects of probiotics on the production of short-chain fatty acids by gut microbes. In addition, the mechanism of formation and properties of these metabolites is discussed and verified test results confirming the effectiveness of probiotics in human nutrition by modulating SCFAs production by intestinal microbiome is presented.
  • 7.6K
  • 30 Oct 2020
Topic Review
35 Mm Film
35 mm film (millimeter) is the film gauge most commonly used for motion pictures and chemical still photography (see 135 film). The name of the gauge refers to the width of the photographic film, which consists of strips 34.98 ±0.03 mm (1.377 ±0.001 inches) wide. The standard negative pulldown for movies ("single-frame" format) is four perforations per frame along both edges, which results in 16 frames per foot of film. For still photography, the standard frame has eight perforations on each side. A variety of largely proprietary gauges were devised for the numerous camera and projection systems being developed independently in the late 19th century and early 20th century, ranging from 13 to 75 mm (0.51 to 2.95 in), as well as a variety of film feeding systems. This resulted in cameras, projectors, and other equipment having to be calibrated to each gauge. The 35 mm width, originally specified as ​1 3⁄8 inches, was introduced in 1892 by William Dickson and Thomas Edison, using 120 film stock supplied by George Eastman. Film 35 mm wide with four perforations per frame became accepted as the international standard gauge in 1909, and remained by far the dominant film gauge for image origination and projection until the advent of digital photography and cinematography, despite challenges from smaller and larger gauges, because its size allowed for a relatively good trade-off between the cost of the film stock and the quality of the images captured. The gauge has been versatile in application. It has been modified to include sound, redesigned to create a safer film base, formulated to capture color, has accommodated a bevy of widescreen formats, and has incorporated digital sound data into nearly all of its non-frame areas. Eastman Kodak, Fujifilm and Agfa-Gevaert are some companies that offered 35 mm films. Today Kodak is the last remaining manufacturer of motion picture film. The ubiquity of 35 mm movie projectors in commercial movie theaters made 35 mm the only motion picture format that could be played in almost any cinema in the world, until digital projection largely superseded it in the 21st century. It is difficult to compare the quality of film to digital media, but a good estimate would be about 33.6 megapixels (67.2 megapixels DSLR Bayer equivalent) would equal one 35-millimeter high quality color frame of film.
  • 7.6K
  • 18 Oct 2022
Topic Review
Word Processor (Electronic Device)
A word processor is an electronic device (later a computer software application) for text, composing, editing, formatting, and printing. The word processor was a stand-alone office machine in the 1960s, combining the keyboard text-entry and printing functions of an electric typewriter with a recording unit, either tape or floppy disk (as used by the Wang machine) with a simple dedicated computer processor for the editing of text. Although features and designs varied among manufacturers and models, and new features were added as technology advanced, the first word processors typically featured a monochrome display and the ability to save documents on memory cards or diskettes. Later models introduced innovations such as spell-checking programs, and improved formatting options. As the more versatile combination of personal computers and printers became commonplace, and computer software applications for word processing became popular, most business machine companies stopped manufacturing dedicated word processor machines. As of 2009 there were only two U.S. companies, Classic and AlphaSmart, which still made them.[needs update] Many older machines, however, remain in use. Since 2009, Sentinel has offered a machine described as a "word processor", but it is more accurately a highly specialised microcomputer used for accounting and publishing. Word processing was one of the earliest applications for the personal computer in office productivity, and was the most widely used application on personal computers until the World Wide Web rose to prominence in the mid-1990s. Although the early word processors evolved to use tag-based markup for document formatting, most modern word processors take advantage of a graphical user interface providing some form of what-you-see-is-what-you-get ("WYSIWYG") editing. Most are powerful systems consisting of one or more programs that can produce a combination of images, graphics and text, the latter handled with type-setting capability. Typical features of a modern word processor include multiple font sets, spell checking, grammar checking, a built-in thesaurus, automatic text correction, web integration, HTML conversion, pre-formatted publication projects such as newsletters and to-do lists, and much more. Microsoft Word is the most widely used word processing software according to a user tracking system built into the software. Microsoft estimates that roughly half a billion people use the Microsoft Office suite, which includes Word. Many other word processing applications exist, including WordPerfect (which dominated the market from the mid-1980s to early-1990s on computers running Microsoft's MS-DOS operating system, and still (2014) is favored for legal applications), Apple's Pages application, and open source applications such as OpenOffice.org Writer, LibreOffice Writer, AbiWord, KWord, and LyX. Web-based word processors such as Office Online or Google Docs are a relatively new category.
  • 7.5K
  • 24 Nov 2022
Topic Review
Basalt
Basalt (/bəˈsɔːlt, ˈbæsɒlt, -sɔːlt/) is a mafic extrusive igneous rock formed from the rapid cooling of magnesium-rich and iron-rich lava exposed at or very near the surface of a terrestrial planet or a moon. More than 90% of all volcanic rock on Earth is basalt. Basalt lava has a low viscosity, due to its low silica content, resulting in rapid lava flows that can spread over great areas before cooling and solidification. Flood basalt describes the formation in a series of lava basalt flows.
  • 7.5K
  • 09 Nov 2022
Topic Review
Edible Mushrooms
Edible mushrooms are considered an important next-generation healthy food source. Edible mushrooms are rich in proteins, dietary fiber, vitamins, minerals, and other bioactive components (alkaloids, lactones, polysaccharides, polyphenolic compounds, sesquiterpenes, sterols, and terpenoids). 
  • 7.5K
  • 06 Dec 2022
Topic Review
Smart manufacturing, an advanced form of traditional manufacturing
Traditional manufacturing is an industrial process that converts materials into a finished product using a labor-intensive low-end operation, low precision, average resource utilization and efficiency for economic value.
  • 7.5K
  • 28 Mar 2022
Topic Review
Determination of Gear Mesh Stiffness
Properly designed gear geometry has a positive effect on the dynamic response of the system, which can be observed on the frequency spectrum of the investigated dynamic system. This geometry has a noticeable effect on the reduced emission of noise in around. What is manifested in the frequency spectrum of gears is mainly the effect of internal excitation caused by the mesh stiffness, which changes during the meshing and thus interferes with the course of torsional dynamic processes of the gear systems. It is therefore necessary to take into account the mesh stiffness when designing the gearbox and to incorporate its course into the dynamic equations of motion. There are various ways to visualize, simulate, and calculate the course of mesh stiffness of gearing. There are different variants of analytical calculations. One of the variants of analytical modeling is the possibility of calculating the mesh stiffness by calculating the deformation energy of individual teeth of the gear. 
  • 7.5K
  • 23 Jun 2021
Topic Review
Tropylium Ion
The tropylium ion is a non-benzenoid aromatic species that works as a catalyst. This chemical entity brings about a large number of organic transformations, such as hydroboration reactions, ring contraction, the trapping of enolates, oxidative functionalization, metathesis, insertion, acetalization, and trans-acetalization reactions. The tropylium ion also functions as a coupling reagent in synthetic reactions. This cation’s versatility can be seen in its role in the synthesis of macrocyclic compounds and cage structures.
  • 7.5K
  • 01 Jun 2023
Topic Review
Reindeer Distribution
The reindeer is a widespread and numerous species in the northern Holarctic, being present in both tundra and taiga (boreal forest). Originally, the reindeer was found in Scandinavia, eastern Europe, Russia , Mongolia, and northern China north of the 50th latitude. In North America, it was found in Canada , Alaska (United States ), and the northern contiguous USA from Washington to Maine. In the 19th century, it was apparently still present in southern Idaho. It also occurred naturally on Sakhalin, Greenland, and probably even in historical times in Ireland. During the late Pleistocene era, reindeer were found further south, such as at Nevada, Tennessee , and Alabama in North America and Spain in Europe. Today, wild reindeer have disappeared from many areas within this large historical range, especially from the southern parts, where it vanished almost everywhere. Populations of wild reindeer are still found in Norway , Finland , Siberia, Greenland, Alaska, and Canada . Domesticated reindeer are mostly found in northern Fennoscandia and Russia, with a herd of approximately 150–170 semi-domesticated reindeer living around the Cairngorms region in Scotland. The last remaining wild tundra reindeer in Europe are found in portions of southern Norway . A few reindeer from Norway were introduced to the South Atlantic island of South Georgia in the beginning of the 20th century. The South Georgian reindeer totaled some estimated 2600 animals in two distinct herds separated by glaciers. Although the flag and the coat of arms of the territory contain an image of a reindeer, they were eradicated from 2013 to 2017 because of the environmental damage they caused. Around 4000 reindeer have been introduced into the French sub-Antarctic archipelago of Kerguelen Islands. East Iceland has a small herd of about 2500–3000 animals. Caribou and reindeer numbers have fluctuated historically, but many herds are in decline across their range. This global decline is linked to climate change for northern, migratory caribou and reindeer herds and industrial disturbance of caribou habitat for sedentary, non-migratory herds.
  • 7.5K
  • 28 Nov 2022
Topic Review
List of Instruction Sets
A list of computer central processor instruction sets: (By alphabetical order by its manufacturer.)
  • 7.5K
  • 04 Nov 2022
Topic Review
Product Distribution
A product distribution is a probability distribution constructed as the distribution of the product of random variables having two other known distributions. Given two statistically independent random variables X and Y, the distribution of the random variable Z that is formed as the product is a product distribution.
  • 7.5K
  • 11 Nov 2022
Topic Review
Accretion (Astrophysics)
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.
  • 7.5K
  • 11 Nov 2022
Topic Review
Aestheticization of Violence
The aestheticization of violence in high culture art or mass media has been the subject of considerable controversy and debate for centuries. In Western art, graphic depictions of the Passion of Christ have long been portrayed, as have a wide range of depictions of warfare by later painters and graphic artists. Theater and, in modern times, cinema have often featured battles and violent crimes, while images and descriptions of violence have always been a part of literature. Margaret Bruder states that the aestheticization of violence in film is the depiction of violence in a "stylistically excessive", "significant and sustained way" in which audience members are able to connect references from the "play of images and signs" to artworks, genre conventions, cultural symbols, or concepts.
  • 7.5K
  • 15 Nov 2022
Topic Review
An Insight into Psychedelic Drugs in Schizophrenia
Schizophrenia remains a serious chronic mental illness since its revelation more than a century ago by Dr. Emile Kraepelin. Despite the low prevalence, nearly 24 million people suffer from this disorder, which constitutes 1 in 300 people (0.32%) of the world’s population and this rate is 1 in 222 people (0.45%) among adults. The symptoms of schizophrenia more often appear in the second or third decade of life, and disease occurrence is tied to a combination of factors such as genetic, socio-demographic, and environmental factor. Clinical schizophrenia is presented in two unique and distinct sets of symptomatology, which include ‘positive’ symptoms and ‘negative’ symptoms, and is also accompanied by significant impairment of cognitive functioning in one or more major areas. This may include an inability to execute work, interpersonal relations, or self-care, and there is also a failure to achieve the expected level of interpersonal, academic, or occupational functioning. According to the current Diagnostic and Statistical Manual for mental disorders-V (DSM-V), the positive symptoms of schizophrenia are delusions, hallucinations, disorganized speech, and behaviour; and the negative symptoms are diminished emotional expression or avolitio. These symptoms have been found to be chronically present once the disease starts, but generally the illness is marked as alternate signs of remission and exacerbation or partial remission or exacerbation. Some psychotic symptoms may be treated without the need for medication with proper human care, social support and care including electroconvulsive therapy.
  • 7.5K
  • 08 Jun 2022
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