Summary

HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Meaning-Text Theory
Meaning-text theory (MTT) is a theoretical linguistic framework, first put forward in Moscow by Aleksandr Žolkovskij and Igor Mel’čuk, for the construction of models of natural language. The theory provides a large and elaborate basis for linguistic description and, due to its formal character, lends itself particularly well to computer applications, including machine translation, phraseology, and lexicography.
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  • 14 Oct 2022
Topic Review
News Server Operation
Among the operators and users of commercial Usenet news servers, common concerns are the continually increasing storage and network capacity requirements and their effects. Completion (the ability of a server to successfully receive all traffic), retention (the amount of time articles are made available to readers) and overall system performance are the topics of frequent discussion. With the increasing demands, it is common for the transit and reader server roles to be subdivided further into numbering, storage and front end systems. These server farms are continually monitored by both insiders and outsiders, and measurements of these characteristics are often used by consumers when choosing a commercial news service.
  • 661
  • 12 Oct 2022
Topic Review
VIPS
VIPS is an open source image processing software package. It is particularly good with large images, works with multi-core processors, working with colour, scientific analysis and general research & development. It was developed during and is the product of several European research projects (VASARI, MARC, ACOHIR, Viseum) which were primarily about Imaging art, but which demanded a new approach to image processing. Compared to most image processing libraries VIPS needs little RAM and runs quickly, especially on machines with more than one CPU. This is primarily due to its architecture which automatically parallelises the image workflows. The software has two main parts: libvips is the image-processing library and nip2 is the graphical user-interface. The GUI aims to be about half-way between Photoshop and Excel. It is not designed for tasks such as retouching photographs, but more useful for the many other imaging tasks that programs like Photoshop are used for. Both work on Linux, Unix, Windows and Apple macOS (10.2 and later). VIPS is a standard package for many Linux distributions
  • 644
  • 12 Oct 2022
Topic Review
Color Coding Technology for Visualization
Color coding technology for data visualization Data visualization achieves its significance today due to information technology: big data processed in computers with capable visualization software, combined with statistical techniques and color coding on electronic displays. This article is about color coding technology for data visualization. Origins of color coding include rubrics, the Four Color Theorem of cartography and Jacques Bertin's 1967 book, The Semiology of Graphics. Contemporary color coding for data visualization is enabled by four technologies: statistics, color technology, displays and computing. Visualization of data was proceduralized by statisticians John Tukey and Edward Tufte in their respective landmark books Exploratory Data Analysis in 1977 and Visual Display of Quantitative Information in 1982. They did not emphasize the use of color. Others demonstrated the superiority of color coding to speed visual search of displayed information, and to locate and organize information of interest. A third prerequisite for color-coded data visualization is high-resolution, high-contrast, high-luminance color electronic displays. Honeywell Corporation and Boeing Corporation assembled technical data that are still germane to use of color displays. More recently, the US Federal Aviation Administration has published technical guidance for visualization of dynamic (air traffic) data on self-luminous color displays. Humans have an innate ability to perform color-coded visual search. Without training or practice, the search time with color coding can be reduced by a factor of ten or more, compared to a search of the same information display without color coding. 
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  • 12 Oct 2022
Topic Review
Trichiida
Trichiida (synonymous with Trichiales T.Macbrd.) is an order of slime moulds in the phylum Amoebozoa. Trichiida is one of five orders in the group Myxomycetes (also called Myxogastria), or the true plasmodial slime molds. It is also currently categorized under the superorder Lucisporidia with its sister group, Liceida. The order was first described by Thomas MacBride in 1922, and has retained the same name and status as a defined order in present phylogeny. In the plasmodium form, members of Trichiida lack a columella but have a well-developed capillitium for spore dispersal. The shape and details of the capillitium are used to define families within the order. Spores are brightly coloured, ranging from clear, white and yellow to pink and red-brown tones. The order currently has 4 families, 14 genera and 174 species. Recent molecular research has shown that while Trichiida probably represents a true taxonomic group, its sister group Liceida is likely paraphyletic, and it has been suggested that several genera from the Liceida should be reclassified under Trichiida instead.
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  • 12 Oct 2022
Topic Review
Peace Treaty
A peace treaty is an agreement between two or more hostile parties, usually countries or governments, which formally ends a state of war between the parties. It is different from an armistice, which is an agreement to stop hostilities; a surrender, in which an army agrees to give up arms; or a ceasefire or truce, in which the parties may agree to temporarily or permanently stop fighting. The art of negotiating a peace treaty in the modern era has been referred to by legal scholar Christine Bell as the lex pacificatoria, with a peace treaty potentially contributing to the legal framework governing the post conflict period, or jus post bellum.
  • 7.7K
  • 12 Oct 2022
Topic Review
DCas9 Activation System
CRISPR activation (CRISPRa) is one type of CRISPR tool that use modified versions of dCas9, a mutation of Cas9 without endonuclease activity, with added transcriptional activators on dCas9 or the guide RNAs (gRNAs). Like a standard CRISPR-Cas9 system, dCas9 activation systems rely on similar components such as Cas9 variants for modulation or modification of genes, gRNAs to guide Cas9 to intended targets, and vectors for introduction into cells. However, while a standard CRISPR-Cas9 system relies on creating breaks in DNA through the endonuclease activity of Cas9 and then manipulating DNA Repair mechanisms for gene editing, dCas9 activation systems are modified and employ transcriptional activators to increase expression of genes of interest. Such systems are usable for many purposes including but not limited to, genetic screens and overexpression of proteins of interest.
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  • 12 Oct 2022
Topic Review
Aquaporin 4
Aquaporin-4, also known as AQP4, is a water channel protein encoded by the AQP4 gene in humans. AQP4 belongs to the aquaporin family of integral membrane proteins that conduct water through the cell membrane. A limited number of aquaporins are found within the central nervous system (CNS): AQP1, 3, 4, 5, 8, 9, and 11, but more exclusive representation of AQP1, 4, and 9 are found in the brain and spinal cord. AQP4 shows the largest presence in the cerebellum and spinal cord grey matter. In the CNS, AQP4 is the most prevalent aquaporin channel, specifically located at the perimicrovessel astrocyte foot processes, glia limitans, and ependyma. In addition, this channel is commonly found facilitating water movement near cerebrospinal fluid and vasculature. Aquaporin-4 was first identified in 1986. It was the first evidence of the existence of water transport channels. The method that was used to discover the existence of the transport channels was through knockout experiments. With this technique they were able to show the significant role of AQP4 in CNS injuries and brain water imbalances. In 1994 the channel was successfully cloned and initially named Mercury-Insensitive Water Channel.
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  • 12 Oct 2022
Topic Review
Chronographer
A chronographer was a graphical representation of historical information devised by American educator Emma Willard in the mid-19th century. The chronographers intended to show historical information in a geographic and chronological context. The first graphic was Picture of Nations, published in 1835, which showed civilizations as streams running through time, becoming wider and narrower as they gained or lost influence. She developed another chronographer, the Chronographer of American History, in 1844, showing the history of the United States as events marked on the branches of a tree. Later chronographers showed historical events within an imagined Ancient Greek temple; the Temple of Time (1846), American Temple of Time (late 1840s), English Chronographer (1849) and Chronographer of Ancient History (1851) are examples of this type. In these chronographers the floor was occupied with the streams of civilizations, as in the Picture of Nations; the walls (often colonnaded) denoted the passage of time and were marked with historical leaders and the roof was split into categories to list other historic persons. The back wall of the temple was often marked as the point of biblical creation, sometimes with the date of 4004 BC from the Ussher chronology, though in her American Temple of Time a map of the continent is used. The birth of Christ was often denoted with a white star and other biblical figures included. Willard's chronographers were intended as learning aids, allowing students to place themselves within the imaginary temple and to consider events in their historic and geographic context. She presented her chronographers at the Great Exhibition in London in 1851 and received a medal and certificate from Albert, Prince Consort. Willard's work has been disparaged by later writers, including for their almost complete omission of non-Western peoples and events.
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  • 12 Oct 2022
Topic Review
Heteroscedasticity
In statistics, a vector of random variables is heteroscedastic (or heteroskedastic; from Ancient Greek hetero "different" and skedasis "dispersion") if the variability of the random disturbance is different across elements of the vector. Here, variability could be quantified by the variance or any other measure of statistical dispersion. Thus heteroscedasticity is the absence of homoscedasticity. A typical example is the set of observations of income in different cities. The existence of heteroscedasticity is a major concern in regression analysis and the analysis of variance, as it invalidates statistical tests of significance that assume that the modelling errors all have the same variance. While the ordinary least squares estimator is still unbiased in the presence of heteroscedasticity, it is inefficient and generalized least squares should be used instead. Because heteroscedasticity concerns expectations of the second moment of the errors, its presence is referred to as misspecification of the second order. The econometrician Robert Engle was awarded the 2003 Nobel Memorial Prize for Economics for his studies on regression analysis in the presence of heteroscedasticity, which led to his formulation of the autoregressive conditional heteroscedasticity (ARCH) modeling technique.
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  • 14 Oct 2022
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