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https://en.wikipedia.org/wiki/Debian%E2%80%93Mozilla%20trademark%20dispute
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In 2006, a branding issue developed when Mike Connor, representing the Mozilla Corporation, requested that the Debian Project comply with Mozilla standards for use of the Thunderbird trademark when redistributing the Thunderbird software. At issue were modifications not approved by the Mozilla Foundation, when the name for the software remained the same.
The Debian Project subsequently rebranded the Mozilla Firefox program, and other software released by Mozilla, so that Debian could distribute modified software without being bound by the trademark requirements that the Mozilla Foundation had invoked. The new names established by Debian were Iceweasel for Mozilla Firefox, Icedove for Mozilla Thunderbird, and Iceape for SeaMonkey. These changes were implemented in the subsequent version of Debian (Etch). In July 2007, Iceowl, a rebranded version of Mozilla Sunbird, was added to the unstable branch of Debian.
In 2016, a number of Mozilla employees and Debian maintainers argued that the branding was no longer needed, and on 10 March 2016, Debian's unstable branch switched back to the Mozilla branding, with the stable branch planning to switch after Iceweasel's end of life.
The decade-long branding issues between the Debian Project and Mozilla Corporation ended in 2017 when all Mozilla applications in Debian were reverted to their original names.
Applications
Debian's Iceweasel, Icedove, Iceowl, and Iceape were based on Mozilla's Firefox, Thunderbird, Sunbird, and SeaMonkey, respectively. The rebranded products still used some Internet-based services from Mozilla, including the Mozilla plugin finder service, and Mozilla add-ons and their update notifications. There was also no change to how non-free components, such as Flash, were found or used.
Iceape
Iceape was a free software Internet suite based on SeaMonkey. It was developed by the Debian Mozilla Team in unison with the SeaMonkey Council's work on their release, but in accordance with Debian's policy of only
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https://en.wikipedia.org/wiki/Advisory%20Committee%20on%20Human%20Radiation%20Experiments
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The Advisory Committee on Human Radiation Experiments was established in 1994 to investigate questions of the record of the United States government with respect to human radiation experiments. The special committee was created by President Bill Clinton in Executive Order 12891, issued January 15, 1994. Ruth Faden of The Johns Hopkins Berman Institute of Bioethics chaired the committee.
The thousand-page final report of the Committee was released in October 1995 at a White House ceremony.
Background
The scandal first came to public attention in a newsletter called Science Trends in 1976 and in Mother Jones magazine in 1981. Mother Jones reporter Howard Rosenburg used the Freedom of Information Act to gather hundreds of documents to investigate total radiation studies which were done at the Oak Ridge Institute for Nuclear Studies (now the Oak Ridge Institute for Science and Education). The Mother Jones article triggered a hearing before the Subcommittee on Investigations and Oversight of the House Science and Technology Committee. Congressman Al Gore of Tennessee chaired the hearing. Gore's subcommittee report stated that the radiation experiments were "satisfactory, but not perfect."
In November 1986, a report by the staff of Massachusetts Congressman Ed Markey was released, but received only cursory media coverage. Entitled "American Nuclear Guinea Pigs: Three decades of radiation experiments on U.S. citizens", the report stated that there had been 31 human radiation experiments involving nearly 700 people. Markey urged the Department of Energy to make every effort to find the experimental subjects and compensate them for damages, which did not occur. DOE officials knew who had conducted the experiments, and the names of some of the subjects. After the report was released, President Ronald Reagan and Vice-President George H. W. Bush resisted opening investigations of the radiation experiments.
The Markey report found that between 1945 and 1947 eighteen hospita
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https://en.wikipedia.org/wiki/WWMB
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WWMB, virtual channel 21 (UHF digital channel 26), is a Dabl-affiliated television station licensed to Florence, South Carolina, United States, serving the Pee Dee and Grand Strand regions of South Carolina. The station is owned by Howard Stirk Holdings; the Sinclair Broadcast Group, which owns dual ABC/CW affiliate WPDE-TV (channel 15, also licensed to Florence), operates WWMB under a shared services agreement (SSA). Both stations share studios on University Boulevard in Conway, while WWMB's transmitter is located on Pee Dee Church Road in Floydale, South Carolina.
History
WWMB went on the air September 21, 1994, as an independent station. It was owned by Atlantic Media Group, but operated by Diversified Communications, then-owner of WPDE, under an LMA. It joined UPN as a charter affiliate on January 16, 1995. By 1999, WWMB was airing Access Hollywood starring Myrtle Beach native Nancy O'Dell. Barrington Broadcasting bought WPDE in 2006. At the same time, Atlantic Media Group sold WWMB to SagamoreHill Broadcasting, which continued the LMA with WPDE.
On January 24, 2006, Time Warner and CBS Corporation announced that the two networks they owned, The WB and UPN, would cease operations, and that those companies would combine their resources to create The CW. Just hours after the announcement, WPDE released a notice on its website indicating WWMB would become an affiliate of the new network. This notice was a little premature, as over the next two months, many announcements of network affiliation changes including station deals with The CW were made.
The existence of a cable-only WB affiliate, "WFWB," which was carried by area cable systems as part of The WB 100+ national cable service, made a CW affiliation for WWMB seem less of a sure thing. Nevertheless, WWMB made public on April 10 it had joined The CW.
Even though WWMB aired CW programming on its individually-programmed main channel, it also operated a digital subchannel that carried the programming of The CW
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https://en.wikipedia.org/wiki/Wet-bulb%20temperature
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The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in water-soaked (water at ambient temperature) cloth (a wet-bulb thermometer) over which air is passed. At 100% relative humidity, the wet-bulb temperature is equal to the air temperature (dry-bulb temperature); at lower humidity the wet-bulb temperature is lower than dry-bulb temperature because of evaporative cooling.
The wet-bulb temperature is defined as the temperature of a parcel of air cooled to saturation (100% relative humidity) by the evaporation of water into it, with the latent heat supplied by the parcel. A wet-bulb thermometer indicates a temperature close to the true (thermodynamic) wet-bulb temperature. The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only.
Even heat-adapted people cannot carry out normal outdoor activities past a wet-bulb temperature of , equivalent to a heat index of . A reading of – equivalent to a heat index of – is considered the theoretical human survivability limit for up to six hours of exposure.
Intuition
If a thermometer is wrapped in a water-moistened cloth, it will behave differently. The drier and less humid the air is, the faster the water will evaporate. The faster water evaporates, the lower the thermometer's temperature will be relative to air temperature.
Water can evaporate only if the air around it can absorb more water. This is measured by comparing how much water is in the air to the maximum that could be in the air—the relative humidity. 0% means the air is completely dry, and 100% means the air contains all the water it can hold in the present circumstances and it cannot absorb any more water (from any source).
This is part of the cause of apparent temperature in humans. The drier the air, the more moisture it can take up beyond what is already in it, and the easier it is for extra water to evaporate. The result is that sweat evaporates more
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https://en.wikipedia.org/wiki/Ball-jointed%20doll
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A ball-jointed doll is any doll that is articulated with ball and socket joints. In contemporary usage when referring to modern dolls, and particularly when using the acronyms BJD or ABJD, it usually refers to modern Asian ball-jointed dolls. These are cast in polyurethane synthetic resin, a hard, dense plastic, and the parts strung together with a thick elastic. They are predominantly produced in Japan, South Korea and China. The BJD style has been described as both realistic and influenced by anime. They commonly range in size from about for the larger dolls, for the mini dolls, and down to for the very smallest BJDs. BJDs are primarily intended for adult collectors and customizers. They are made to be easy to customize, by painting, changing the eyes and wig, and so forth.
The modern BJD market began with the Volks line of Super Dollfie in 1999. Super Dollfie and Dollfie are registered trademarks but are sometimes erroneously used as generic blanket terms to refer to all Asian BJDs regardless of manufacturer.
History
Articulated dolls go back to at least 200 BCE, with articulated clay and wooden dolls of ancient Greece and Rome. The modern era of ball-jointed doll history began in Western Europe in the late 19th century. From the late 19th century through the early 20th century, French and German manufacturers made bisque dolls with strung bodies articulated with ball joints made of composition: a mix of pulp, sawdust, glue, and similar materials. These dolls could measure between and are now collectible antiques.
During the 1930s, the German artist Hans Bellmer created dolls with ball joints and used them in photography and other surrealistic artwork. Bellmer introduced the idea of artful doll photography, which continues today with Japanese doll artists, as well as BJD hobbyists.
Influenced by Bellmer and the rich Japanese doll tradition, Japanese artists began creating strung ball-jointed art dolls. These are commonly made entirely of bisque and are o
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https://en.wikipedia.org/wiki/Caudal%20regression%20syndrome
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Caudal regression syndrome, or sacral agenesis (or hypoplasia of the sacrum), is a rare birth defect. It is a congenital disorder in which the fetal development of the lower spine—the caudal partition of the spine—is abnormal. It occurs at a rate of approximately one per 60,000 live births.
Some babies are born with very small differences compared to typical development, and others have significant changes. Most grow up to be otherwise typical adults who have difficulty with walking and incontinence.
Signs and symptoms
This condition exists in a variety of forms, ranging from partial absence of the tail bone regions of the spine to absence of the lower vertebrae, pelvis and parts of the thoracic and/or lumbar areas of the spine. In some cases, where only a small part of the spine is absent, there may be no outward sign of the condition. In cases where more substantial areas of the spine are absent, there may be fused, webbed or smaller lower extremities and paralysis. Bowel and bladder control is usually affected.
Cause
The condition arises from some factor or set of factors present during approximately the 3rd week to 7th week of fetal development. Formation of the sacrum/lower back and corresponding nervous system is usually nearing completion by the 4th week of development. Due to abnormal gastrulation, the mesoderm migration is disturbed. This disturbance results in symptoms varying from minor lesions of the lower vertebrae to more severe symptoms such as complete fusion of the lower limbs. While the exact cause is unknown, it has been speculated that the condition has a combination of environmental and genetic causes, and that various types of the condition may have differing causes.
Sacral agenesis syndrome (a type of caudal regression syndrome involving agenesis of the lumbar spine, sacrum, and coccyx, and hypoplasia of the lower extremities) is a well-established congenital anomaly associated with maternal diabetes mellitus. Other causes are presumably
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https://en.wikipedia.org/wiki/Rutherford%20model
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The Rutherford model was devised by the New Zealand-born physicist Ernest Rutherford to describe an atom. Rutherford directed the Geiger–Marsden experiment in 1909, which suggested, upon Rutherford's 1911 analysis, that J. J. Thomson's plum pudding model of the atom was incorrect. Rutherford's new model for the atom, based on the experimental results, contained new features of a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and with this central volume containing most of the atom's mass. This region would be known as the atomic nucleus.
Experimental basis for the model
Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure. If Thomson was correct, the beam would go straight through the gold foil. Most of the beams went through the foil, but a few were deflected.
Rutherford presented his own physical model for subatomic structure, as an interpretation for the unexpected experimental results. In it, the atom is made up of a central charge (this is the modern atomic nucleus, though Rutherford did not use the term "nucleus" in his paper) surrounded by a cloud of (presumably) orbiting electrons. In this May 1911 paper, Rutherford only committed himself to a small central region of very high positive or negative charge in the atom.
For concreteness, consider the passage of a high speed α particle through an atom having a positive central charge N e, and surrounded by a compensating charge of N electrons.
From purely energetic considerations of how far particles of known speed would be able to penetrate toward a central charge of 100 e, Rutherford was able to calculate that the radius of his gold central charge would need to be less (how much less could not be told) t
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https://en.wikipedia.org/wiki/Bordeaux%20mixture
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Bordeaux mixture (also called Bordo Mix) is a mixture of copper(II) sulphate (CuSO4) and quicklime (CaO) used as a fungicide. It is used in vineyards, fruit-farms and gardens to prevent infestations of downy mildew, powdery mildew and other fungi. It is sprayed on plants as a preventive treatment; its mode of action is ineffective after a fungus has become established. It was invented in the Bordeaux region of France in the late 19th century. If it is applied in large quantities annually for many years, the copper in the mixture eventually becomes a pollutant. As such its use is illegal in most of the European Union. Despite this, it has been promoted as an 'organic' pesticide.
Main uses
In addition to its use to control fungal infection on grape vines, the mixture is also widely used to control potato blight, peach leaf curl and apple scab. Although it may be bad for the environment, some organic agriculture advocates allow its use, so is often used by organic gardeners in some parts of the world.
Because the copper ions build up in the soil, continuous use will cause heavy metal pollution. Copper also bioaccumulates in organisms. It is thus illegal to use in most European Union countries, with the exception of Cyprus, Greece, Hungary, Italy, Malta, Portugal, Romania and Slovenia.
Mode of action
Bordeaux mixture achieves its effect by means of the copper ions (Cu2+) of the mixture. These ions affect enzymes in the fungal spores in such a way as to prevent germination. This means Bordeaux mixture must be used preventively, before the fungal disease has struck.
Thorough coverage of the spray on the plants is necessary. The Bordeaux spray continues to adhere well to the plant during rain, though in the long term it is washed off by rain. Commonly in practice, it is applied just once a year, in the wintertime.
Preparation
Bordeaux mixture can be prepared using differing proportions of the components. In preparing it, the CuSO4 and the lime are dissolved separatel
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https://en.wikipedia.org/wiki/Gosper%20curve
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The Gosper curve, named after Bill Gosper, also known as the Peano-Gosper Curve and the flowsnake (a spoonerism of snowflake), is a space-filling curve whose limit set is rep-7. It is a fractal curve similar in its construction to the dragon curve and the Hilbert curve.
The Gosper curve can also be used for efficient hierarchical hexagonal clustering and indexing.
Algorithm
Lindenmayer system
The Gosper curve can be represented using an L-system with rules as follows:
Angle: 60°
Axiom:
Replacement rules:
In this case both A and B mean to move forward, + means to turn left 60 degrees and - means to turn right 60 degrees - using a "turtle"-style program such as Logo.
Logo
A Logo program to draw the Gosper curve using turtle graphics:
to rg :st :ln
make "st :st - 1
make "ln :ln / sqrt 7
if :st > 0 [rg :st :ln rt 60 gl :st :ln rt 120 gl :st :ln lt 60 rg :st :ln lt 120 rg :st :ln rg :st :ln lt 60 gl :st :ln rt 60]
if :st = 0 [fd :ln rt 60 fd :ln rt 120 fd :ln lt 60 fd :ln lt 120 fd :ln fd :ln lt 60 fd :ln rt 60]
end
to gl :st :ln
make "st :st - 1
make "ln :ln / sqrt 7
if :st > 0 [lt 60 rg :st :ln rt 60 gl :st :ln gl :st :ln rt 120 gl :st :ln rt 60 rg :st :ln lt 120 rg :st :ln lt 60 gl :st :ln]
if :st = 0 [lt 60 fd :ln rt 60 fd :ln fd :ln rt 120 fd :ln rt 60 fd :ln lt 120 fd :ln lt 60 fd :ln]
end
The program can be invoked, for example, with rg 4 300, or alternatively gl 4 300.
Python
A Python program, that uses the aforementioned L-System rules, to draw the Gosper curve using turtle graphics (online version):
import turtle
def gosper_curve(order: int, size: int, is_A: bool = True) -> None:
"""Draw the Gosper curve."""
if order == 0:
turtle.forward(size)
return
for op in "A-B--B+A++AA+B-" if is_A else "+A-BB--B-A++A+B":
gosper_op_map[op](order - 1, size)
gosper_op_map = {
"A": lambda o, size: gosper_curve(o, size, True),
"B": lambda o, size: gosper_curve(o, size, False),
"-": lambda o, size: t
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https://en.wikipedia.org/wiki/Newton%20fractal
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The Newton fractal is a boundary set in the complex plane which is characterized by Newton's method applied to a fixed polynomial or transcendental function. It is the Julia set of the meromorphic function which is given by Newton's method. When there are no attractive cycles (of order greater than 1), it divides the complex plane into regions , each of which is associated with a root of the polynomial, . In this way the Newton fractal is similar to the Mandelbrot set, and like other fractals it exhibits an intricate appearance arising from a simple description. It is relevant to numerical analysis because it shows that (outside the region of quadratic convergence) the Newton method can be very sensitive to its choice of start point.
Almost all points of the complex plane are associated with one of the roots of a given polynomial in the following way: the point is used as starting value for Newton's iteration {{math|zn + 1 : zn − {{sfrac|p(zn)|p'''(zn)}}}}, yielding a sequence of points If the sequence converges to the root , then was an element of the region . However, for every polynomial of degree at least 2 there are points for which the Newton iteration does not converge to any root: examples are the boundaries of the basins of attraction of the various roots. There are even polynomials for which open sets of starting points fail to converge to any root: a simple example is , where some points are attracted by the cycle rather than by a root.
An open set for which the iterations converge towards a given root or cycle (that is not a fixed point), is a Fatou set for the iteration. The complementary set to the union of all these, is the Julia set. The Fatou sets have common boundary, namely the Julia set. Therefore, each point of the Julia set is a point of accumulation for each of the Fatou sets. It is this property that causes the fractal structure of the Julia set (when the degree of the polynomial is larger than 2).
To plot images of the fractal,
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https://en.wikipedia.org/wiki/Lyndon%20word
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In mathematics, in the areas of combinatorics and computer science, a Lyndon word is a nonempty string that is strictly smaller in lexicographic order than all of its rotations. Lyndon words are named after mathematician Roger Lyndon, who investigated them in 1954, calling them standard lexicographic sequences. Anatoly Shirshov introduced Lyndon words in 1953 calling them regular words. Lyndon words are a special case of Hall words; almost all properties of Lyndon words are shared by Hall words.
Definitions
Several equivalent definitions exist.
A -ary Lyndon word of length is an -character string over an alphabet of size , and which is the unique minimum element in the lexicographical ordering in the multiset of all its rotations. Being the singularly smallest rotation implies that a Lyndon word differs from any of its non-trivial rotations, and is therefore aperiodic.
Alternately, a word is a Lyndon word if and only if it is nonempty and lexicographically strictly smaller than any of its proper suffixes, that is for all nonempty words such that and is nonempty.
Another characterisation is the following: A Lyndon word has the property that it is nonempty and, whenever it is split into two nonempty substrings, the left substring is always lexicographically less than the right substring. That is, if is a Lyndon word, and is any factorization into two substrings, with and understood to be non-empty, then . This definition implies that a string of length is a Lyndon word if and only if there exist Lyndon words and such that and . Although there may be more than one choice of and with this property, there is a particular choice, called the standard factorization, in which is as long as possible.
Enumeration
The Lyndon words over the two-symbol binary alphabet {0,1}, sorted by length and then lexicographically within each length class, form an infinite sequence that begins
0, 1, 01, 001, 011, 0001, 0011, 0111, 00001, 00011, 00101, 00111, 01011, 0
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https://en.wikipedia.org/wiki/Remineralisation
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In biogeochemistry, remineralisation (or remineralization) refers to the breakdown or transformation of organic matter (those molecules derived from a biological source) into its simplest inorganic forms. These transformations form a crucial link within ecosystems as they are responsible for liberating the energy stored in organic molecules and recycling matter within the system to be reused as nutrients by other organisms.
Remineralisation is normally viewed as it relates to the cycling of the major biologically important elements such as carbon, nitrogen and phosphorus. While crucial to all ecosystems, the process receives special consideration in aquatic settings, where it forms a significant link in the biogeochemical dynamics and cycling of aquatic ecosystems.
Role in biogeochemistry
The term "remineralization" is used in several contexts across different disciplines. The term is most commonly used in the medicinal and physiological fields, where it describes the development or redevelopment of mineralized structures in organisms such as teeth or bone. In the field of biogeochemistry, however, remineralization is used to describe a link in the chain of elemental cycling within a specific ecosystem. In particular, remineralization represents the point where organic material constructed by living organisms is broken down into basal inorganic components that are not obviously identifiable as having come from an organic source. This differs from the process of decomposition which is a more general descriptor of larger structures degrading to smaller structures.
Biogeochemists study this process across all ecosystems for a variety of reasons. This is done primarily to investigate the flow of material and energy in a given system, which is key to understanding the productivity of that ecosystem along with how it recycles material versus how much is entering the system. Understanding the rates and dynamics of organic matter remineralization in a given system can
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https://en.wikipedia.org/wiki/Zero%20suppression
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Zero suppression is the removal of redundant zeroes from a number. This can be done for storage, page or display space constraints or formatting reasons, such as making a letter more legible.
Examples
00049823 → 49823
7.678600000 → 7.6786
0032.3231000 → 32.3231
2.45000×1010 → 2.45×1010
0.0045×1010 → 4.5×107
One must be careful; in physics and related disciplines, trailing zeros are used to indicate the precision of the number, as an error of ±1 in the last place is assumed. Examples:
4.5981 is 4.5981 ± 0.0001
4.59810 is 4.5981 ± 0.00001
4.598100 is 4.5981 ± 0.000001
Data compression
It is also a way to store a large array of numbers, where many of the entries are zero. By omitting the zeroes, and instead storing the indices along with the values of the non-zero items, less space may be used in total. It only makes sense if the extra space used for storing the indices (on average) is smaller than the space saved by not storing the zeroes. This is sometimes used in a sparse array.
Example:
Original array: 0, 1, 0, 0, 2, 5, 0, 0, 0, 4, 0, 0, 0, 0, 0
Pairs of index and data: {2,1}, {5,2}, {6,5}, {10,4}
See also
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https://en.wikipedia.org/wiki/Deutsch%20limit
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The Deutsch limit is an aphorism about the information density of visual programming languages originated by L. Peter Deutsch that states:
The problem with visual programming is that you can’t have more than 50 visual primitives on the screen at the same time.
The term was made up by Fred Lakin, after Deutsch made the following comment at a talk on visual programming by Scott Kim and Warren Robinett: "Well, this is all fine and well, but the problem with visual programming languages is that you can't have more than 50 visual primitives on the screen at the same time. How are you going to write an operating system?"
The primitives in a visual language are the separate graphical elements used to build a program, and having more of them available at the same time allows the programmer to read more information. This limit is sometimes cited as an example of the advantage of textual over visual languages, pointing out the greater information density of text, and posing a difficulty in scaling the language.
However, criticisms of the limit include that it is not clear whether a similar limit also exists in textual programming languages; and that the limit could be overcome by applying modularity to visual programming as is commonly done in textual programming.
See also
Cognitive dimensions of notations
Conway's law
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https://en.wikipedia.org/wiki/Polyamorphism
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Polyamorphism is the ability of a substance to exist in several different amorphous modifications. It is analogous to the polymorphism of crystalline materials. Many amorphous substances can exist with different amorphous characteristics (e.g. polymers). However, polyamorphism requires two distinct amorphous states with a clear, discontinuous (first-order) phase transition between them. When such a transition occurs between two stable liquid states, a polyamorphic transition may also be referred to as a liquid–liquid phase transition.
Overview
Even though amorphous materials exhibit no long-range periodic atomic ordering, there is still significant and varied local structure at inter-atomic length scales (see structure of liquids and glasses). Different local structures can produce amorphous phases of the same chemical composition with different physical properties such as density. In several cases sharp transitions have been observed between two different density amorphous states of the same material. Amorphous ice is one important example (see also examples below). Several of these transitions (including water) are expected to end in a second critical point.
Liquid–liquid transitions
Polyamorphism may apply to all amorphous states, i.e. glasses, other amorphous solids, supercooled liquids, ordinary liquids or fluids. A liquid–liquid transition however, is one that occurs only in the liquid state (red line in the phase diagram, top right). In this article liquid–liquid transitions are defined as transitions between two liquids of the same chemical substance. Elsewhere the term liquid–liquid transition may also refer to the more common transitions between liquid mixtures of different chemical composition.
The stable liquid state unlike most glasses and amorphous solids, is a thermodynamically stable equilibrium state. Thus new liquid–liquid or fluid-fluid transitions in the stable liquid (or fluid) states are more easily analysed than transitions in amorphous so
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https://en.wikipedia.org/wiki/URL%20shortening
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URL shortening is a technique on the World Wide Web in which a Uniform Resource Locator (URL) may be made substantially shorter and still direct to the required page. This is achieved by using a redirect which links to the web page that has a long URL. For example, the URL "" can be shortened to "", and the URL "" can be shortened to "". Often the redirect domain name is shorter than the original one. A friendly URL may be desired for messaging technologies that limit the number of characters in a message (for example SMS), for reducing the amount of typing required if the reader is copying a URL from a print source, for making it easier for a person to remember, or for the intention of a permalink. In November 2009, the shortened links of the URL shortening service Bitly were accessed 2.1 billion times.
Other uses of URL shortening are to "beautify" a link, track clicks, or disguise the underlying address. This is because the URL shortener can redirect to just about any web domain, even malicious ones. So, although disguising of the underlying address may be desired for legitimate business or personal reasons, it is open to abuse. Some URL shortening service providers have found themselves on spam blocklists, because of the use of their redirect services by sites trying to bypass those very same blocklists. Some websites prevent short, redirected URLs from being posted.
Purposes
There are several reasons to use URL shortening. Often regular unshortened links may be aesthetically unpleasing. Many web developers pass descriptive attributes in the URL to represent data hierarchies, command structures, transaction paths or session information. This can result in URLs that are hundreds of characters long and that contain complex character patterns. Such URLs are difficult to memorize, type out or distribute. As a result, long URLs must be copied and pasted for reliability. Thus, short URLs may be more convenient for websites or hard copy publications (e.g. a printe
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https://en.wikipedia.org/wiki/Cc%3AMail
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cc:Mail is a discontinued store-and-forward LAN-based email system originally developed on Microsoft's MS-DOS platform by Concentric Systems, Inc. in the 1980s. The company, founded by Robert Plummer, Hubert Lipinski, and Michael Palmer, later changed its name to PCC Systems, Inc., and then to cc:Mail, Inc. At the height of its popularity, cc:Mail had about 14 million users, and won various awards for being the top email software package of the mid-1990s.
Architecture overview
In the 1980s and 1990s, it became common in office environments to have a personal computer on every desk, all connected via a local area network (LAN). Typically, (at least) one computer is set up as a file server, so that any computer on the LAN can store and access files on the server as if they were local files. cc:Mail was designed to operate in that environment.
The central point of focus in the cc:Mail architecture is the cc:Mail "post office," which is a collection of files located on the file server and consisting of the message store and related data. However, no cc:Mail software needs to be installed or run on the file server itself. The cc:Mail application is installed on the user desktops. It provides a user interface, and reads and writes to the post office files directly in order to send, access, and manage email messages. This arrangement is called a "shared-file mail system" (which was also implemented later in competing products such as Microsoft Mail). This is in contrast to a "client/server mail system" which involves a mail client application interacting with a mail server application (the latter then being the focal point of message handling). Client/server mail was added later to the cc:Mail product architecture (see below), and also became available in competing offerings (such as Microsoft Exchange).
Other than the cc:Mail desktop application, key software elements of the cc:Mail architecture include cc:Mail Router (for transferring messages between post offices,
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https://en.wikipedia.org/wiki/Transfer%20learning
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Transfer learning (TL) is a technique in machine learning (ML) in which knowledge learned from a task is re-used in order to boost performance on a related task. For example, for image classification, knowledge gained while learning to recognize cars could be applied when trying to recognize trucks. This topic is related to the psychological literature on transfer of learning, although practical ties between the two fields are limited. Reusing/transferring information from previously learned tasks to new tasks has the potential to significantly improve learning efficiency.
History
In 1976, Bozinovski and Fulgosi published a paper addressing transfer learning in neural network training. The paper gives a mathematical and geometrical model of the topic. In 1981, a report considered the application of transfer learning to a dataset of images representing letters of computer terminals, experimentally demonstrating positive and negative transfer learning.
In 1993, Pratt formulated the discriminability-based transfer (DBT) algorithm.
In 1997, Pratt and Thrun guest-edited a special issue of Machine Learning devoted to transfer learning, and by 1998, the field had advanced to include multi-task learning, along with more formal theoretical foundations. Learning to Learn, edited by Thrun and Pratt, is a 1998 review of the subject.
Transfer learning has been applied in cognitive science. Pratt guest-edited an issue of Connection Science on reuse of neural networks through transfer in 1996.
Ng said in his NIPS 2016 tutorial that TL would become the next driver of machine learning commercial success after supervised learning.
In the 2020 paper, "Rethinking Pre-Training and self-training", Zoph et al. reported that pre-training can hurt accuracy, and advocate self-training instead.
Applications
Algorithms are available for transfer learning in Markov logic networks and Bayesian networks. Transfer learning has been applied to cancer subtype discovery, building utilization
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https://en.wikipedia.org/wiki/History%20of%20Microsoft%20Flight%20Simulator
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Microsoft Flight Simulator began as a set of articles on computer graphics, written by Bruce Artwick throughout 1976, about flight simulation using 3-D graphics. When the editor of the magazine told Artwick that subscribers were interested in purchasing such a program, Artwick founded Sublogic Corporation to commercialize his ideas. At first the new company sold flight simulators through mail order, but that changed in January 1979 with the release of Flight Simulator (FS) for the Apple II. They soon followed this up with versions for other systems and from there it evolved into a long-running series of computer flight simulators.
Sublogic flight simulators
First generation (Apple II and TRS-80)
− January 1979 for Apple II
− January 1980 for TRS-80
Second generation (Tandy Color Computer 3, Apple II, Commodore 64, and Atari 8-bit)
− December 1983 for Apple II
− June 1984 for Commodore 64
− October 1984 for Atari 8-bit family
− Sometime in 1987 for CoCo 3
Third generation (Amiga, Atari ST, and Macintosh)
− March 1986 for Apple Macintosh
− November 1986 for Amiga and Atari ST
In 1984, Amiga Corporation asked Artwick to port Flight Simulator for its forthcoming computer, but Commodore's purchase of Amiga temporarily ended the relationship. Sublogic instead finished a Macintosh version, released by Microsoft, then resumed work on the Amiga and Atari ST versions.
Although still called Flight Simulator II, the Amiga and Atari ST versions compare favorably with Microsoft Flight Simulator 3.0. Notable features included a windowing system allowing multiple simultaneous 3d views - including exterior views of the aircraft itself - and (on the Amiga and Atari ST) modem play.
Info gave the Amiga version five out of five, describing it as the "finest incarnation". Praising the "superb" graphics, the magazine advised to "BEGIN your game collection with this one!"
Microsoft Flight Simulator
Flight Simulator 1.0
− Released in November 1982
Flight Simulator 2.0
− Releas
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https://en.wikipedia.org/wiki/Q-derivative
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In mathematics, in the area of combinatorics and quantum calculus, the q-derivative, or Jackson derivative, is a q-analog of the ordinary derivative, introduced by Frank Hilton Jackson. It is the inverse of Jackson's q-integration. For other forms of q-derivative, see .
Definition
The q-derivative of a function f(x) is defined as
It is also often written as . The q-derivative is also known as the Jackson derivative.
Formally, in terms of Lagrange's shift operator in logarithmic variables, it amounts to the operator
which goes to the plain derivative, as .
It is manifestly linear,
It has a product rule analogous to the ordinary derivative product rule, with two equivalent forms
Similarly, it satisfies a quotient rule,
There is also a rule similar to the chain rule for ordinary derivatives. Let . Then
The eigenfunction of the q-derivative is the q-exponential eq(x).
Relationship to ordinary derivatives
Q-differentiation resembles ordinary differentiation, with curious differences. For example, the q-derivative of the monomial is:
where is the q-bracket of n. Note that so the ordinary derivative is regained in this limit.
The n-th q-derivative of a function may be given as:
provided that the ordinary n-th derivative of f exists at x = 0. Here, is the q-Pochhammer symbol, and is the q-factorial. If is analytic we can apply the Taylor formula to the definition of to get
A q-analog of the Taylor expansion of a function about zero follows:
Higher order q-derivatives
The following representation for higher order -derivatives is known:
is the -binomial coefficient. By changing the order of summation as , we obtain the next formula:
Higher order -derivatives are used to -Taylor formula and the -Rodrigues' formula (the formula used to construct -orthogonal polynomials).
Generalizations
Post Quantum Calculus
Post quantum calculus is a generalization of the theory of quantum calculus, and it uses the following operator:
Hahn difference
Wolfgang Hahn i
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https://en.wikipedia.org/wiki/Letterer%E2%80%93Siwe%20disease
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Letterer–Siwe disease, (LSD) or Abt-Letterer-Siwe disease, is one of the four recognized clinical syndromes of Langerhans cell histiocytosis (LCH) and is the most severe form, involving multiple organ systems such as the skin, bone marrow, spleen, liver, and lung. Oral cavity and gastrointestinal involvement may also be seen.
LCH and all its subtypes are characterized by monoclonal migration and proliferation of specific dendritic cells.
The subcategorization of Letterer-Siwe disease is a historical eponym. Designating the four subtypes of LCH as separate entities are mostly of historical significance, because they are varied manifestations of the same underlying disease process, and patients also often exhibit symptoms from more than one of the four syndromes.
Letterer-Siwe causes approximately 10% of LCH disease.
Prevalence is estimated at 1:500,000 and the disease almost exclusively occurs in children less than three years old. It is more common among Caucasian patients than in African American patients.
Children with LCH with single organ involvement tend to have a better prognosis than patients with the multi-system involvement seen in Letter-Siwe disease.
The name is derived from the names of Erich Letterer and Sture Siwe.
Presentation
Letterer-Siwe typically presents in children less than 2 years old, and the clinical manifestations may include:
In a more severe course or in later phases of the disease, patients may present with hemorrhage and sepsis secondary to hepatic failure and severe pancytopenia. A purpuric rash or bruise may be apparent right before death in a patient who has a hemorrhagic tendency.
Cause
In general, the cause of Langerhans Cell Histiocytosis is unknown. Regardless of the subtype of Langerhans cell histiocytosis, the pathologic hallmark for all subtypes of LCH is the abnormal proliferation and accumulation of immature Langerhans cells, macrophages, lymphocytes, and eosinophils. The collection of these cells is what forms gr
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https://en.wikipedia.org/wiki/Categorical%20set%20theory
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Categorical set theory is any one of several versions of set theory developed from or treated in the context of mathematical category theory.
See also
Categorical logic
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https://en.wikipedia.org/wiki/Phyllody
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Phyllody is the abnormal development of floral parts into leafy structures. It is generally caused by phytoplasma or virus infections, though it may also be because of environmental factors that result in an imbalance in plant hormones. Phyllody causes the affected plant to become partially or entirely sterile, as it is unable to produce normal flowers.
The condition is also known as phyllomorphy or frondescence; though the latter may sometimes refer more generically to foliage, leafiness, or the process of leaf growth. Phyllody is usually differentiated from floral virescence, wherein the flowers merely turn green in color but otherwise retain their normal structure. However, floral virescence and phyllody (along with witch's broom and other growth abnormalities), commonly occur together as symptoms of the same diseases. The term chloranthy is also often used for phyllody (particularly flowers exhibiting complete phyllody, such that it resembles leaf buds more than flowers), though in some cases it may refer to floral virescence.
History
In the late 18th century, the German poet and philosopher Johann Wolfgang von Goethe noted strange-looking rose flowers where the flower organs were replaced by leafy or stem-like structures. This led him to hypothesize that plant organs arising from the stem are simply modifications of the same basic leaf organ. During growth, these organs naturally differentiate into specialized or generalized structures like petals or leaves. However, if certain factors interfere during the early growth stages, these organs can develop into something other than the original "plan of construction". He called this abnormal growth "metamorphosis" and it is the main topic of his essay Versuch die Metamorphose der Pflanzen zu erklären (1790), better known in English as the Metamorphosis of Plants. Goethe's hypothesis was poorly received by other scientists during his time, but it is now known to be essentially correct. The concepts he discusses whi
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https://en.wikipedia.org/wiki/Robot%20calibration
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Robot calibration is a process used to improve the accuracy of robots, particularly industrial robots which are highly repeatable but not accurate. Robot calibration is the process of identifying certain parameters in the kinematic structure of an industrial robot, such as the relative position of robot links. Depending on the type of errors modeled, the calibration can be classified in three different ways. Level-1 calibration only models differences between actual and reported joint displacement values, (also known as mastering). Level-2 calibration, also known as kinematic calibration, concerns the entire geometric robot calibration which includes angle offsets and joint lengths. Level-3 calibration, also called a non-kinematic calibration, models errors other than geometric defaults such as stiffness, joint compliance, and friction. Often Level-1 and Level-2 calibration are sufficient for most practical needs.
Parametric robot calibration is the process of determining the actual values of kinematic and dynamic parameters of an industrial robot (IR). Kinematic parameters describe the relative position and orientation of links and joints in the robot while the dynamic parameters describe arm and joint masses and internal friction.
Non-parametric robot calibration circumvents the parameter identification. Used with serial robots, it is based on the direct compensation of mapped errors in the workspace. Used with parallel robots, non-parametric calibration can be performed by the transformation of the configuration space.
Robot calibration can remarkably improve the accuracy of robots programmed offline. A calibrated robot has a higher absolute as well as relative positioning accuracy compared to an uncalibrated one; i.e., the real position of the robot end effector corresponds better to the position calculated from the mathematical model of the robot. Absolute positioning accuracy is particularly relevant in connection with robot exchangeability and off-line pr
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https://en.wikipedia.org/wiki/Firewall%20pinhole
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In computer networking, a firewall pinhole is a port that is not protected by a firewall to allow a particular application to gain access to a service on a host in the network protected by the firewall.
Leaving ports open in firewall configurations exposes the protected system to potentially malicious abuse. A fully closed firewall prevents applications from accessing services on the other side of the firewall. For protection, the mechanism for opening a pinhole in the firewall should implement user validation and authorization.
For firewalls performing a network address translation (NAT) function, the mapping between the external {IP address, port} socket and the internal {IP address, port} socket is often called a pinhole.
Pinholes can be created manually or programmatically. They can be temporary, created dynamically for a specific duration such as for a dynamic connection, or permanent, such as for signaling functions.
Firewalls sometimes automatically close pinholes after a period of time (typically a few minutes) to minimize the security exposure. Applications that require a pinhole to be kept open often need to generate artificial traffic through the pinhole in order to cause the firewall to restart its timer.
See also
Port forwarding
Port triggering
NAT hole punching
NAT traversal
TCP hole punching
UDP hole punching
ICMP hole punching
Port Control Protocol (PCP)
NAT Port Mapping Protocol (NAT-PMP)
Internet Gateway Device Protocol (UPnP IGD)
Computer network security
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https://en.wikipedia.org/wiki/Titanium%20aluminide
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Titanium aluminide (chemical formula TiAl), commonly gamma titanium, is an intermetallic chemical compound. It is lightweight and resistant to oxidation and heat, but has low ductility. The density of γ-TiAl is about 4.0 g/cm3. It finds use in several applications including aircraft, jet engines, sporting equipment and automobiles. The development of TiAl based alloys began circa 1970. The alloys have been used in these applications only since about 2000.
Titanium aluminide has three major intermetallic compounds: gamma titanium aluminide (gamma TiAl, γ-TiAl), alpha 2-Ti3Al and TiAl3. Among the three, gamma TiAl has received the most interest and applications.
Applications of gamma-TiAl
Gamma TiAl has excellent mechanical properties and oxidation and corrosion resistance at elevated temperatures (over 600°C), which makes it a possible replacement for traditional Ni based superalloy components in aircraft turbine engines.
TiAl-based alloys have potential to increase the thrust-to-weight ratio in aircraft engines. This is especially the case with the engine's low-pressure turbine blades and the high-pressure compressor blades. These are traditionally made of Ni-based superalloy, which is nearly twice as dense as TiAl-based alloys. Some gamma titanium aluminide alloys retain strength and oxidation resistance to 1000 °C, which is 400 °C higher than the operating temperature limit of conventional titanium alloys.
General Electric uses gamma TiAl for the low-pressure turbine blades on its GEnx engine, which powers the Boeing 787 and Boeing 747-8 aircraft. This was the first large-scale use of this material on a commercial jet engine when it entered service in 2011. The TiAl LPT blades are cast by Precision Castparts Corp. and Avio s.p.a. Machining of the Stage 6, and Stage 7 LPT blades is performed by Moeller Manufacturing. An alternate pathway for production of the gamma TiAl blades for the GEnx and GE9x engines using additive manufacturing is being explored.
In
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https://en.wikipedia.org/wiki/Electric%20spark
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An electric spark is an abrupt electrical discharge that occurs when a sufficiently high electric field creates an ionized, electrically conductive channel through a normally-insulating medium, often air or other gases or gas mixtures. Michael Faraday described this phenomenon as "the beautiful flash of light attending the discharge of common electricity".
The rapid transition from a non-conducting to a conductive state produces a brief emission of light and a sharp crack or snapping sound. A spark is created when the applied electric field exceeds the dielectric breakdown strength of the intervening medium. For air, the breakdown strength is about 30 kV/cm at sea level. Experimentally, this figure tends to differ depending upon humidity, atmospheric pressure, shape of electrodes (needle and ground-plane, hemispherical etc.) and the corresponding spacing between them and even the type of waveform, whether sinusoidal or cosine-rectangular. At the beginning stages, free electrons in the gap (from cosmic rays or background radiation) are accelerated by the electrical field. As they collide with air molecules, they create additional ions and newly freed electrons which are also accelerated. At some point, thermal energy will provide a much greater source of ions. The exponentially-increasing electrons and ions rapidly cause regions of the air in the gap to become electrically conductive in a process called dielectric breakdown. Once the gap breaks down, current flow is limited by the available charge (for an electrostatic discharge) or by the impedance of the external power supply. If the power supply continues to supply current, the spark will evolve into a continuous discharge called an electric arc. An electric spark can also occur within insulating liquids or solids, but with different breakdown mechanisms from sparks in gases.
Sometimes, sparks can be dangerous. They can cause fires and burn skin.
Lightning is an example of an electric spark in nature, while
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https://en.wikipedia.org/wiki/Monopulse%20radar
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Monopulse radar is a radar system that uses additional encoding of the radio signal to provide accurate directional information. The name refers to its ability to extract range and direction from a single signal pulse.
Monopulse radar avoids problems seen in conical scanning radar systems, which can be confused by rapid changes in signal strength. The system also makes jamming more difficult. Most radars designed since the 1960s are monopulse systems. The monopulse method is also used in passive systems, such as electronic support measures and radio astronomy. Monopulse radar systems can be constructed with reflector antennas, lens antennas or array antennas.
Historically, monopulse systems have been classified as either phase-comparison monopulse or amplitude monopulse. Modern systems determine the direction from the monopulse ratio, which contain both amplitude and phase information. The monopulse method does not require that the measured signals are pulsed. The alternative name "simultaneous lobing" has therefore been suggested, but not popularized.
Background
Conical scan
Conical scanning is not considered to be a form of monopulse radar, but the following summary provides background that can aid understanding.
Conical scan systems send out a signal slightly to one side of the antenna's boresight and then rotate the feed horn to make the lobe rotate around the boresight line. A target centered on the boresight is always slightly illuminated by the lobe, and provides a strong return. If the target is to one side, it will be illuminated only when the lobe is pointed in that general direction, resulting in a weaker signal overall (or a flashing one if the rotation is slow enough). This varying signal will reach a maximum when the antenna is rotated so it is aligned in the direction of the target.
By looking for this maximum and moving the antenna in that direction, a target can be automatically tracked. This is greatly eased by using two antennas, angled
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https://en.wikipedia.org/wiki/Comparison%20of%20DNS%20server%20software
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This article presents a comparison of the features, platform support, and packaging of many independent implementations of Domain Name System (DNS) name server software.
Servers compared
Each of these DNS servers is an independent implementation of the DNS protocols, capable of resolving DNS names for other computers, publishing the DNS names of computers, or both. Excluded from consideration are single-feature DNS tools (such as proxies, filters, and firewalls) and redistributions of servers listed here (many products repackage BIND, for instance, with proprietary user interfaces).
DNS servers are grouped into several categories of specialization of servicing domain name system queries. The two principal roles, which may be implemented either uniquely or combined in a given product are:
Authoritative server: authoritative name servers publish DNS mappings for domains under their authoritative control. Typically, a company (e.g. "Acme Example Widgets") would provide its own authority services to respond to address queries, or for other DNS information, for www.example.int. These servers are listed as being at the top of the authority chain for their respective domains, and are capable of providing a definitive answer. Authoritative name servers can be primary name servers, also known as master servers, i.e. they contain the original set of data, or they can be secondary or slave name servers, containing data copies usually obtained from synchronization directly with the primary server, either via a DNS mechanism, or by other data store synchronization mechanisms.
Recursive server: recursive servers (sometimes called "DNS caches", "caching-only name servers") provide DNS name resolution for applications, by relaying the requests of the client application to the chain of authoritative name servers to fully resolve a network name. They also (typically) cache the result to answer potential future queries within a certain expiration (time-to-live) period. Most I
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https://en.wikipedia.org/wiki/Sudan%20function
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In the theory of computation, the Sudan function is an example of a function that is recursive, but not primitive recursive. This is also true of the better-known Ackermann function. The Sudan function was the first function having this property to be published.
It was discovered (and published ) in 1927 by Gabriel Sudan, a Romanian mathematician who was a student of David Hilbert.
Definition
Value tables
Values of F0
F0(x, y) = x + y
Values of F1
F1(x, y) = 2y · (x + 2) − y − 2
Values of F2
Values von F3
Notes and references
Bibliography
External links
OEIS: A260003, A260004
Arithmetic
Large integers
Special functions
Theory of computation
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https://en.wikipedia.org/wiki/First%20Data
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First Data Corporation is a financial services company headquartered in Atlanta, Georgia, United States. The company's STAR Network provides nationwide domestic debit acceptance at more than 2 million retail POS, ATM, and at online outlets for nearly a third of all U.S. debit cards.
First Data has six million merchants, the largest in the payments industry. The company handles 45% of all US credit and debit transactions, including handling prepaid gift card processing for many US brands such as Starbucks. It processes around 2,800 transactions per second and $2.2 trillion in card transactions annually, with an 80% market share in gas and groceries in 2014. First Data's SpendTrend Report is frequently used by national news networks such as WSJ, USA Today, ESPN, The New York Times, Vox Media, and Bloomberg.
On January 16, 2019, Fiserv announced a deal to acquire First Data in an all-stock deal with equity value of $22 billion. Fiserv completed the acquisition of First Data on Monday, July 29, 2019.
History
In 1969, the Mid-America Bankcard Association (MABA) was formed in Omaha, Nebraska, as a non-profit bankcard processing cooperative. First Data Resources (FDR) was founded in Omaha, Nebraska in June 1971 by Perry "Bill" Esping, along with Mike Liddy and Jack Weekly. It started off by providing processing services to the Mid-America Bankcard Association (MABA). In 1976, First Data became the first processor of Visa and MasterCard bank-issued credit cards. In 1980, American Express Information Services Corporation (ISC) bought 80% of First Data. The remaining 20% was purchased in 5% increments each subsequent year until June 1983. First Data Corporation was incorporated on April 7, 1989.
First Data Corporation was spun off from American Express and went public in 1992. In 1995, the company merged with First Financial Management Corp. (FFMC) and was then organized into three major business units serving card issuers, merchants, and consumers. Western Union became
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https://en.wikipedia.org/wiki/Enumerative%20combinatorics
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Enumerative combinatorics is an area of combinatorics that deals with the number of ways that certain patterns can be formed. Two examples of this type of problem are counting combinations and counting permutations. More generally, given an infinite collection of finite sets Si indexed by the natural numbers, enumerative combinatorics seeks to describe a counting function which counts the number of objects in Sn for each n. Although counting the number of elements in a set is a rather broad mathematical problem, many of the problems that arise in applications have a relatively simple combinatorial description. The twelvefold way provides a unified framework for counting permutations, combinations and partitions.
The simplest such functions are closed formulas, which can be expressed as a composition of elementary functions such as factorials, powers, and so on. For instance, as shown below, the number of different possible orderings of a deck of n cards is f(n) = n!. The problem of finding a closed formula is known as algebraic enumeration, and frequently involves deriving a recurrence relation or generating function and using this to arrive at the desired closed form.
Often, a complicated closed formula yields little insight into the behavior of the counting function as the number of counted objects grows.
In these cases, a simple asymptotic approximation may be preferable. A function is an asymptotic approximation to if as . In this case, we write
Generating functions
Generating functions are used to describe families of combinatorial objects. Let denote the family of objects and let F(x) be its generating function. Then
where denotes the number of combinatorial objects of size n. The number of combinatorial objects of size n is therefore given by the coefficient of . Some common operation on families of combinatorial objects and its effect on the generating function will now be developed.
The exponential generating function is also sometimes used. I
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https://en.wikipedia.org/wiki/Helikon%20vortex%20separation%20process
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The Helikon vortex separation process is an aerodynamic uranium enrichment process designed around a device called a vortex tube. Paul Dirac thought of the idea for isotope separation and tried creating such a device in 1934 in the lab of Peter Kapitza at Cambridge. Other methods of separation were more practical at that time, but this method was designed and used in South Africa for producing reactor fuel with a uranium-235 content of around 3–5%, and 80–93% enriched uranium for use in nuclear weapons. The Uranium Enrichment Corporation of South Africa, Ltd. (UCOR) developed the process, operating a facility at Pelindaba (known as the 'Y' plant) to produce hundreds of kilograms of HEU. Aerodynamic enrichment processes require large amounts of electricity and are not generally considered economically competitive because of high energy consumption and substantial requirements for removal of waste heat. There are other ways in which it is advantageous, e.g. In simplicity, lack of precision required, even if more expensive. The South African enrichment plant was closed on 1 February 1990.
Process
In the vortex separation process a mixture of uranium hexafluoride gas and hydrogen is injected tangentially into a tube at one end through nozzles or holes, at velocities close to the speed of sound. The tube tapers to a small exit aperture at one or both ends. This tangential injection of gas results in a spiral or vortex motion within the tube, and two gas streams are withdrawn at opposite ends of the vortex tube; centrifugal force providing the isotopic separation. The spiral swirling flow decays downstream of the feed inlet due to friction at the tube wall. Consequently, the inside diameter of the tube is typically tapered to reduce decay in the swirling flow velocity. This process is characterized by a separating element with a very small stage cut (the ratio of product flow to feed flow) of about 1/20, and high process-operating pressures.
Due to the extremely diffi
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https://en.wikipedia.org/wiki/Unconventional%20computing
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Unconventional computing is computing by any of a wide range of new or unusual methods. It is also known as alternative computing.
The term unconventional computation was coined by Cristian S. Calude and John Casti and used at the First International Conference on Unconventional Models of Computation in 1998.
Background
The general theory of computation allows for a variety of models. Computing technology first developed using mechanical systems and then evolved into the use of electronic devices. Other fields of modern physics provide additional avenues for development.
Computational model
Computational models use computer programs to simulate and study complex systems using an algorithmic or mechanistic approach. They are commonly used to study complex nonlinear systems for which simple analytical solutions are not readily available. Experimentation with the model is done by adjusting parameters in the computer and studying the differences in the outcome. Operation theories of the model can be derived/deduced from these computational experiments. Examples of computational models include weather forecasting models, earth simulator models, flight simulator models, molecular protein folding models, and neural network models.
Mechanical computing
Historically, mechanical computers were used in industry before the advent of the transistor.
Mechanical computers retain some interest today both in research and as analogue computers. Some mechanical computers have a theoretical or didactic relevance, such as billiard-ball computers, while hydraulic ones like the MONIAC or the Water integrator were used effectively.
While some are actually simulated, others are not. No attempt is made to build a functioning computer through the mechanical collisions of billiard balls. The domino computer is another theoretically interesting mechanical computing scheme.
Analog computing
An analog computer is a type of computer that uses analog signals, which are continuous physi
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https://en.wikipedia.org/wiki/Timarit.is
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Timarit.is (also known as Tímarit.is, Tidarrit.fo and Aviisitoqqat.gl) is an open access digital library run by the National and University Library of Iceland which hosts digital editions of newspapers and magazines published in Iceland, Faroe Islands and Greenland as well as publications in their languages elsewhere, such as Canada which had a large influx of Icelanders in the late 19th and early 20th centuries. The project was initially sponsored by the West Nordic Council and launched its web interface under the title VESTNORD in 2002. The web interface has since undergone two major revisions, in 2003 and 2008. With the last revision a decision was made to gradually convert images from the DjVu image format to the more common PDF. Hence, part of the collection can be viewed with the DjVu plugin and part with a PDF reader.
The digital collection covers material from the 17th century to the early 21st century and offers users the ability to collect bookmarks on their free account for ease of use as well as do a text search on the majority of the collection. As of February 2009 there were more than 2,6 million images in the archive of which 2 million had been OCRed.
Initially the aim was to limit access to newspapers published before 1930 to avoid questions of copyright but shortly afterwards the project made an agreement with Morgunblaðið to scan and publish issues which are three years old. This agreement was followed with others involving both current and defunct newspapers published in the 20th century. Newspapers published after 2000 are usually sent to the library in digital format. The general rule, depending on agreements with each publisher, is to make these available 2–3 years after their initial publication.
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https://en.wikipedia.org/wiki/Deme%20%28biology%29
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In biology, a deme, in the strict sense, is a group of individuals that belong to the same taxonomic group. However, when biologists, and especially ecologists, use the term ‘deme’ they usually refer to it as the definition of a gamodeme: a local group of individuals (from the same taxon) that interbreed with each other and share a gene pool. The latter definition of a deme is only applicable to sexual reproducing species, while the former is more neutral and also takes asexual reproducing species into account, such as certain plant species. In the following sections the latter (and most frequently used) definition of a deme will be used.
In evolutionary computation, a "deme" often refers to any isolated subpopulation subjected to selection as a unit rather than as individuals.
Local adaptation
A population of a species usually has multiple demes. Environments between these demes can differ. Demes could, therefore, become locally adapted to their environment. A good example of this is the Adaptive Deme Formation (ADF) hypothesis in insects. The ADF hypothesis states that herbivorous insects can become adapted to specific host plants in their local environment because local plants can have unique nutrient patches to which insects may become adapted. This hypothesis predicts that less mobile insect demes are more likely to become locally adapted than more dispersive insect. However, a meta-analysis, based on 17 studies on this subject, showed that dispersive insect demes were as likely to become locally adapted as less mobile insects. Moreover, this study found a small indication that feeding behaviour might stimulate the local adaptation of demes. Endophagous insects were more likely to become locally adapted than exophagous insects. The explanation for this could be that endophagous insects come in more close and continuous contact to the plant's mechanical, chemical and phenological defensive mechanisms.
Speciation and demes
Speciation could occur at the level
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https://en.wikipedia.org/wiki/Slab%20allocation
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Slab allocation is a memory management mechanism intended for the efficient memory allocation of objects. In comparison with earlier mechanisms, it reduces fragmentation caused by allocations and deallocations.
This technique is used for retaining allocated memory containing a data object of a certain type for reuse upon subsequent allocations of objects of the same type. It is analogous to an object pool, but only applies to memory, not other resources.
Slab allocation was first introduced in the Solaris 2.4 kernel by Jeff Bonwick. It is now widely used by many Unix and Unix-like operating systems including FreeBSD and Linux.
Basis
Slab allocation renders infrequent the very costly practice (in CPU time) of initialization and destruction of kernel data-objects, which can outweigh the cost of allocating memory for them. When the kernel creates and deletes objects often, overhead costs of initialization can result in significant performance drops. Object caching leads to less frequent invocation of functions which initialize object state: when a slab-allocated object is released after use, the slab allocation system typically keeps it cached (rather than doing the work of destroying it) ready for re-use next time an object of that type is needed (thus avoiding the work of constructing and initialising a new object).
With slab allocation, a cache for a certain type or size of data object has a number of pre-allocated "slabs" of memory; within each slab there are memory chunks of fixed size suitable for the objects. The slab allocator keeps track of these chunks, so that when it receives a request to allocate memory for a data object of a certain type, usually it can satisfy the request with a free slot (chunk) from an existing slab. When the allocator is asked to free the object's memory, it just adds the slot to the containing slab's list of free (unused) slots. The next call to create an object of the same type (or allocate memory of the same size) will return
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https://en.wikipedia.org/wiki/KPXJ
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KPXJ (channel 21) is a television station licensed to Minden, Louisiana, United States, serving the Shreveport area as an affiliate of The CW. The station is owned by locally based KTBS, LLC, alongside ABC affiliate KTBS-TV (channel 3). Both stations share studios on East Kings Highway on the eastern side of Shreveport, while KPXJ's transmitter is located near St. Johns Baptist Church Road (southeast of Mooringsport and Caddo Lake) in rural northern Caddo Parish.
History
Early history; as a Pax TV owned-and-operated station
The UHF channel 21 allocation was contested between multiple groups that competed for approval by the Federal Communications Commission (FCC) to be the holder of the construction permit to build and license to operate a new television station on the third commercial UHF allocation to be assigned to the Shreveport–Texarkana market (assigned to the Shreveport suburb of Minden, Louisiana). Among the prospective applicants were John E. Powley (who applied for the license on January 16, 1996), Tucson, Arizona-based Northwest Television Inc. (owned by company president William L. Yde III, president, who applied for the license on January 18, 1996) and five parties who each applied for individual applications on April 4 and 5, 1996: Los Angeles-based Venture Technologies Group LLC (majority owned by Lawrence Rogow, who also served as the group's president), Little Rock-based Kaleidoscope Partners (forerunner company to Equity Broadcasting), Washington, D.C.-based WinStar Broadcasting Corp. (owned by Stuart B. Rekant), Wichita, Kansas-based entrepreneur Marcia T. Turner, Columbia, South Carolina-based Universal Media (majority owned by company president Murray Michaels) and Shreveport-based Word of Life Ministries Inc.
On December 19, 1997, West Palm Beach, Florida-based Paxson Communications (now Ion Media Networks) – which was preparing to launch Pax TV, a family-oriented broadcast television network, that tapped Paxson Communications-owned affiliat
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https://en.wikipedia.org/wiki/KSHV-TV
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KSHV-TV (channel 45) is a television station in Shreveport, Louisiana, United States, affiliated with MyNetworkTV. It is owned by Nexstar Media Group alongside Texarkana, Texas–licensed NBC affiliate KTAL-TV (channel 6); Nexstar also provides certain services to Fox affiliate KMSS-TV (channel 33) under a shared services agreement (SSA) with Mission Broadcasting. The stations share studios on North Market Street and Deer Park Road in northeast Shreveport, while KSHV-TV's transmitter is located southeast of Mooringsport.
History
Early history
The UHF channel 45 allocation in Shreveport was contested between three groups that competed for the Federal Communications Commission (FCC)'s approval of a construction permit to build and license to operate a new television station. Word of Life Ministries Inc. – a non-stock arm of the Word of Life Center, a nondenominational church on West 70th Street/Meriwether Road (near LA 3132) in southwestern Shreveport that was managed by founding church co-pastor Sam Carr – filed the initial application on October 29, 1986. On September 3, 1987, Word of Life Ministries reached a settlement agreement with the second applicant for the license, Media Communications, Inc., which agreed to dismiss its license application. Three months later on December 9, an application by the third applicant for UHF channel 45, Shreveport-based Godfrey & Associates, was dismissed with prejudice by Joseph Chachkin, the administrative law judge appointed in its dispute over the construction permit with Word of Life, for failure to prosecute; this resulted in the FCC granting the permit to Word of Life.
The station signed on the air on April 15, 1994, as KWLB (for "Word of Life Broadcasting"). operating as an independent station. It mostly aired religious programs, family-oriented shows and cartoons. In March 1995, Lafayette-based White Knight Broadcasting (owned by media executive Sheldon Galloway) purchased the station from Word of Life Ministries for $3.
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https://en.wikipedia.org/wiki/Hyperspectral%20imaging
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Hyperspectral imaging collects and processes information from across the electromagnetic spectrum. The goal of hyperspectral imaging is to obtain the spectrum for each pixel in the image of a scene, with the purpose of finding objects, identifying materials, or detecting processes. There are three general types of spectral imagers. There are push broom scanners and the related whisk broom scanners (spatial scanning), which read images over time, band sequential scanners (spectral scanning), which acquire images of an area at different wavelengths, and snapshot hyperspectral imagers, which uses a staring array to generate an image in an instant.
Whereas the human eye sees color of visible light in mostly three bands (long wavelengths - perceived as red, medium wavelengths - perceived as green, and short wavelengths - perceived as blue), spectral imaging divides the spectrum into many more bands. This technique of dividing images into bands can be extended beyond the visible. In hyperspectral imaging, the recorded spectra have fine wavelength resolution and cover a wide range of wavelengths. Hyperspectral imaging measures continuous spectral bands, as opposed to multiband imaging which measures spaced spectral bands.
Engineers build hyperspectral sensors and processing systems for applications in astronomy, agriculture, molecular biology, biomedical imaging, geosciences, physics, and surveillance. Hyperspectral sensors look at objects using a vast portion of the electromagnetic spectrum. Certain objects leave unique 'fingerprints' in the electromagnetic spectrum. Known as spectral signatures, these 'fingerprints' enable identification of the materials that make up a scanned object. For example, a spectral signature for oil helps geologists find new oil fields.
Sensors
Figuratively speaking, hyperspectral sensors collect information as a set of 'images'. Each image represents a narrow wavelength range of the electromagnetic spectrum, also known as a spectral band.
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https://en.wikipedia.org/wiki/Spherical%20law%20of%20cosines
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In spherical trigonometry, the law of cosines (also called the cosine rule for sides) is a theorem relating the sides and angles of spherical triangles, analogous to the ordinary law of cosines from plane trigonometry.
Given a unit sphere, a "spherical triangle" on the surface of the sphere is defined by the great circles connecting three points , and on the sphere (shown at right). If the lengths of these three sides are (from to (from to ), and (from to ), and the angle of the corner opposite is , then the (first) spherical law of cosines states:
Since this is a unit sphere, the lengths , and are simply equal to the angles (in radians) subtended by those sides from the center of the sphere. (For a non-unit sphere, the lengths are the subtended angles times the radius, and the formula still holds if and are reinterpreted as the subtended angles). As a special case, for , then , and one obtains the spherical analogue of the Pythagorean theorem:
If the law of cosines is used to solve for , the necessity of inverting the cosine magnifies rounding errors when is small. In this case, the alternative formulation of the law of haversines is preferable.
A variation on the law of cosines, the second spherical law of cosines, (also called the cosine rule for angles) states:
where and are the angles of the corners opposite to sides and , respectively. It can be obtained from consideration of a spherical triangle dual to the given one.
Proofs
First proof
Let , and denote the unit vectors from the center of the sphere to those corners of the triangle. The angles and distances do not change if the coordinate system is rotated, so we can rotate the coordinate system so that is at the north pole and is somewhere on the prime meridian (longitude of 0). With this rotation, the spherical coordinates for are where is the angle measured from the north pole not from the equator, and the spherical coordinates for are The Cartesian coordinates for ar
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https://en.wikipedia.org/wiki/Rotation%20number
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In mathematics, the rotation number is an invariant of homeomorphisms of the circle.
History
It was first defined by Henri Poincaré in 1885, in relation to the precession of the perihelion of a planetary orbit. Poincaré later proved a theorem characterizing the existence of periodic orbits in terms of rationality of the rotation number.
Definition
Suppose that is an orientation-preserving homeomorphism of the circle Then may be lifted to a homeomorphism of the real line, satisfying
for every real number and every integer .
The rotation number of is defined in terms of the iterates of :
Henri Poincaré proved that the limit exists and is independent of the choice of the starting point . The lift is unique modulo integers, therefore the rotation number is a well-defined element of Intuitively, it measures the average rotation angle along the orbits of .
Example
If is a rotation by (where ), then
and its rotation number is (cf. irrational rotation).
Properties
The rotation number is invariant under topological conjugacy, and even monotone topological semiconjugacy: if and are two homeomorphisms of the circle and
for a monotone continuous map of the circle into itself (not necessarily homeomorphic) then and have the same rotation numbers. It was used by Poincaré and Arnaud Denjoy for topological classification of homeomorphisms of the circle. There are two distinct possibilities.
The rotation number of is a rational number (in the lowest terms). Then has a periodic orbit, every periodic orbit has period , and the order of the points on each such orbit coincides with the order of the points for a rotation by . Moreover, every forward orbit of converges to a periodic orbit. The same is true for backward orbits, corresponding to iterations of , but the limiting periodic orbits in forward and backward directions may be different.
The rotation number of is an irrational number . Then has no periodic orbits (this follows immedi
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https://en.wikipedia.org/wiki/Proof-carrying%20code
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Proof-carrying code (PCC) is a software mechanism that allows a host system to verify properties about an application via a formal proof that accompanies the application's executable code. The host system can quickly verify the validity of the proof, and it can compare the conclusions of the proof to its own security policy to determine whether the application is safe to execute. This can be particularly useful in ensuring memory safety (i.e. preventing issues like buffer overflows).
Proof-carrying code was originally described in 1996 by George Necula and Peter Lee.
Packet filter example
The original publication on proof-carrying code in 1996 used packet filters as an example: a user-mode application hands a function written in machine code to the kernel that determines whether or not an application is interested in processing a particular network packet. Because the packet filter runs in kernel mode, it could compromise the integrity of the system if it contains malicious code that writes to kernel data structures. Traditional approaches to this problem include interpreting a domain-specific language for packet filtering, inserting checks on each memory access (software fault isolation), and writing the filter in a high-level language which is compiled by the kernel before it is run. These approaches have performance disadvantages for code as frequently run as a packet filter, except for the in-kernel compilation approach, which only compiles the code when it is loaded, not every time it is executed.
With proof-carrying code, the kernel publishes a security policy specifying properties that any packet filter must obey: for example, will not access memory outside of the packet and its scratch memory area. A theorem prover is used to show that the machine code satisfies this policy. The steps of this proof are recorded and attached to the machine code which is given to the kernel program loader. The program loader can then rapidly validate the proof, allowing i
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https://en.wikipedia.org/wiki/Biocybernetics
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Biocybernetics is the application of cybernetics to biological science disciplines such as neurology and multicellular systems. Biocybernetics plays a major role in systems biology, seeking to integrate different levels of information to understand how biological systems function. The field of cybernetics itself has origins in biological disciplines such as neurophysiology. Biocybernetics is an abstract science and is a fundamental part of theoretical biology, based upon the principles of systemics. Biocybernetics is a psychological study that aims to understand how the human body functions as a biological system and performs complex mental functions like thought processing, motion, and maintaining homeostasis.(PsychologyDictionary.org)Within this field, many distinct qualities allow for different distinctions within the cybernetic groups such as humans and insects such as beehives and ants. Humans work together but they also have individual thoughts that allow them to act on their own, while worker bees follow the commands of the queen bee. (Seeley, 1989). Although humans often work together, they can also separate from the group and think for themselves.(Gackenbach, J. 2007) A unique example of this within the human sector of biocybernetics would be in society during the colonization period, when Great Britain established their colonies in North America and Australia. Many of the traits and qualities of the mother country were inherited by the colonies, as well as niche qualities that were unique to them based on their areas like language and personality—similar vines and grasses, where the parent plant produces offshoots, spreading from the core. Once the shoots grow their roots and get separated from the mother plant, they will survive independently and be considered their plant. Society is more closely related to plants than to animals since, like plants, there is no distinct separation between parent and offspring. The branching of society is more similar t
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https://en.wikipedia.org/wiki/Ethnoecology
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Ethnoecology is the scientific study of how different groups of people living in different locations understand the ecosystems around them, and their relationships with surrounding environments.
It seeks valid, reliable understanding of how we as humans have interacted with the environment and how these intricate relationships have been sustained over time.
The "ethno" (see ethnology) prefix in ethnoecology indicates a localized study of a people, and in conjunction with ecology, signifies people's understanding and experience of environments around them. Ecology is the study of the interactions between living organisms and their environment; enthnoecology applies a human focused approach to this subject. The development of the field lies in applying indigenous knowledge of botany and placing it in a global context.
History
Ethnoecology began with some of the early works of Dr. Hugh Popenoe, an agronomist and tropical soil scientist who has worked with the University of Florida, the National Science Foundation, and the National Research Council. Popenoe has also worked with Dr Harold Conklin, a cognitive anthropologist who did extensive linguistic and ethnoecological research in Southeast Asia.
In his 1954 dissertation "The Relation of the Hanunoo Culture to the Plant World", Harold Conklin coined the term ethnoecology when he described his approach as "ethnoecological". After earning his PhD, he began teaching at Columbia University while continuing his research among the Hanunoo.
In 1955, Conklin published one of his first ethnoecological studies. His "Hanunoo Color Categories" study helped scholars understand the relationship between classification systems and conceptualization of the world within cultures. In this experiment, Conklin discovered that people in various cultures recognize colors differently due to their unique classification system. Within his results he found that the Hanunoo uses two levels of colors. The first level consists of four basic
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https://en.wikipedia.org/wiki/Worksheet
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A worksheet, in the word's original meaning, is a sheet of paper on which one performs work. They come in many forms, most commonly associated with children's school work assignments, tax forms, and accounting or other business environments. Software is increasingly taking over the paper-based worksheet.
It can be a printed page that a child completes with a writing instrument. No other materials are needed. It is "a sheet of paper on which work schedules, working time, special instructions, etc. are recorded. A piece or scrap of paper on which problems, ideas, or the like, are set down in tentative form." In education, a worksheet may have questions for students and places to record answers.
In accounting, a worksheet is, or was, a sheet of ruled paper with rows and columns on which an accountant could record information or perform calculations. These are often called columnar pads, and typically green-tinted.
In computing, spreadsheet software presents, on a computer monitor, a user interface that resembles one or more paper accounting worksheets. Microsoft Excel, a popular spreadsheet program, refers to a single spreadsheet (more technically, a two-dimensional matrix or array) as a worksheet, and it refers to a collection of worksheets as a workbook.
Education
In the classroom setting, worksheets usually refer to a loose sheet of paper with questions or exercises for students to complete and record answers. They are used, to some degree, in most subjects, and have widespread use in the math curriculum where there are two major types. The first type of math worksheet contains a collection of similar math problems or exercises. These are intended to help a student become proficient in a particular mathematical skill that was taught to them in class. They are commonly given to students as homework. The second type of math worksheet is intended to introduce new topics, and are often completed in the classroom. They are made up of a progressive set of question
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https://en.wikipedia.org/wiki/C7%20protein
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C7 protein is an engineered zinc finger protein based on the murine ZFP, Zif268 and discovered by Wu et al. in 1994 (published in 1995). It shares the same zinc finger 2 and zinc finger 3 of Zif268, but differs in the sequence of finger 1. It also shares the same DNA target, 5'-GCGTGGGCG-3'.
The shared sequences in single letter amino acid codes of fingers 2 and 3 are RSD-H-LTT and RAD-E-RKR (positions -1 through 6 in the alpha helix).
Zinc finger 1 has the sequence KSA-D-LKR which provides a 13-fold increase in affinity to the target sequence of the entire ZFP over that of Zif268.
It is used in zinc finger investigations in which the amino acid sequence of finger 2 is changed in order to determine the appropriate sequence to target a given three-nucleotide target site. A variation of C7, C7.GAT is preferred since it lacks the aspartic acid residue present in finger 3 of C7 and known to cause a phenomenon called 'target site overlap'. In this case the target site overlap is a result of the aspartic acid residue forming a hydrogen bond with the N4 of the cytosine (in the opposite strand) base-paired to the guanine in the finger 2 subsite. It can also form the same hydrogen bond with an adenine base paired to a thymine. This target site overlap would dictate that either a cytosine or adenine residue be present as the 3' nucleotide in the finger 2 subsite which is unacceptable when looking to target sequences containing another nucleotide at this position.
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https://en.wikipedia.org/wiki/C7.GAT%20protein
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The C7.GAT protein is a zinc finger protein based on the C7 protein (itself based on the murine Zif268). It features an alternative zinc finger 3 alpha helix sequence, preventing the target site overlap caused by the aspartic acid residue of the finger 3 of C7. The sequence of this third finger is TSG-N-LVR according to the single letter amino acid code. As the name suggest, the target site of finger 3 is altered to 5'-GAT-3', giving the overall protein a target of 5'-GCGTGGGAT-3'.
C7.GAT is used in studies investigating the effects of altering zinc finger alpha helix sequence on the target of the altered zinc finger, as well as the affinity and specificity of these proteins to their targets.
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https://en.wikipedia.org/wiki/Oracle%20RAC
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In database computing, Oracle Real Application Clusters (RAC) — an option for the Oracle Database software produced by Oracle Corporation and introduced in 2001 with Oracle9i — provides software for clustering and high availability in Oracle database environments. Oracle Corporation includes RAC with the Enterprise Edition, provided the nodes are clustered using Oracle Clusterware.
Functionality
Oracle RAC allows multiple computers to run Oracle RDBMS software simultaneously while accessing a single database, thus providing clustering.
In a non-RAC Oracle database, a single instance accesses a single database. The database consists of a collection of data files, control files, and redo logs located on disk. The instance comprises the collection of Oracle-related memory and background processes that run on a computer system.
In an Oracle RAC environment, 2 or more instances concurrently access a single database. This allows an application or user to connect to either computer and have access to a single coordinated set of data. The instances are connected with each other through an "Interconnect" which enables all the instances to be in sync in accessing the data.
Aims
The main aim of Oracle RAC is to implement a clustered database to provide performance, scalability and resilience & high availability of data at instance level.
Implementation
Oracle RAC depends on the infrastructure component Oracle Clusterware to coordinate multiple servers and their sharing of data storage.
The FAN (Fast Application Notification) technology detects down-states.
RAC administrators can use the srvctl tool to manage RAC configurations,
Cache Fusion
Prior to Oracle 9, network-clustered Oracle databases used a storage device as the data-transfer medium (meaning that one node would write a data block to disk and another node would read that data from the same disk), which had the inherent disadvantage of lackluster performance. Oracle 9i addressed this issue: RAC uses a dedicated
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https://en.wikipedia.org/wiki/Disodium%20glutamate
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Disodium glutamate, abbreviated DSG, (Na2C5H7NO4) is a sodium salt of glutamic acid. It is used as a flavoring agent to impart umami flavor.
Formation
Disodium glutamate can be produced by neutralizing glutamic acid with two molar equivalents of sodium hydroxide (NaOH).
See also
Monosodium glutamate
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https://en.wikipedia.org/wiki/Pickled%20egg
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Pickled eggs are typically hard-boiled eggs that are cured in vinegar or brine. As with many foods, this was originally a way to preserve the food so that it could be eaten months later. Pickled eggs have since become a favorite among many as a snack or hors d'œuvre popular in pubs, bars, and taverns, and around the world in places where beer is served.
After the eggs are hard-boiled, the shell is removed and they are submerged in a solution of vinegar, salt, spices, and other seasonings. Recipes vary from the traditional brine solution for pickles to other solutions, which can impart a sweet or spicy taste.
The final taste is mostly determined by the pickling solution. The eggs are left in this solution from one day to several months. Prolonged exposure to the pickling solution may result in a rubbery texture. A common practice is to puncture the egg with a toothpick to allow the pickling solution to penetrate to the egg's interior, but this is dangerous as it can introduce clostridium into the finished product. Eggs prepared with this method have sometimes had high enough levels of botulinum toxin to cause illness in a human.
Pickled eggs may be served as part of a main course, hors d'œuvres, or garnishes.
Recipes
A variant historically associated with the Pennsylvania Dutch is the pickled beet egg where whole beets, onions, vinegar, sugar, salt, cloves, and (optionally) a cinnamon stick are used as the brine. The eggs take on a pink or even purple color from the beets and have a sweet and sour taste. Pickled red beet eggs, long a common food at picnics and pot-lucks in the Pennsylvania Dutch country, have diffused into the folk cuisine of the surrounding "English" and become a popular snack that can be bought in supermarkets as far east as the Delaware River.
A typical British recipe for pickled eggs includes eggs, vinegar, salt, and sugar. The eggs are then boiled, peeled, then boiled with the other ingredients. They last for three to four months (for best
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https://en.wikipedia.org/wiki/Strain%20hardening%20exponent
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The strain hardening exponent (also called the strain hardening index), usually denoted , a constant often used in calculations relating to stress–strain behavior in work hardening. It occurs in the formula known as Hollomon's equation (after John Herbert Hollomon Jr.) who originally posited it as
where represents the applied true stress on the material, is the true strain, and is the strength coefficient.
The value of the strain hardening exponent lies between 0 and 1, with a value of 0 implying a perfectly plastic solid and a value of 1 representing a perfectly elastic solid. Most metals have an -value between 0.10 and 0.50.
Tabulation
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https://en.wikipedia.org/wiki/Code%20morphing
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Code morphing is an approach used in obfuscating software to protect software applications from reverse engineering, analysis, modifications, and cracking. This technology protects intermediate level code such as compiled from Java and .NET languages (Oxygene, C#, Visual Basic, etc.) rather than binary object code. Code morphing breaks up the protected code into several processor commands or small command snippets and replaces them by others, while maintaining the same end result. Thus the protector obfuscates the code at the intermediate level.
Code morphing is a multilevel technology containing hundreds of unique code transformation patterns. In addition this technology transforms some intermediate layer commands into virtual machine commands (like p-code). Code morphing does not protect against runtime tracing, which can reveal the execution logic of any protected code.
Unlike other code protectors, there is no concept of code decryption with this method. Protected code blocks are always in the executable state, and they are executed (interpreted) as transformed code. The original intermediate code is absent to a certain degree, but deobfuscation can still give a clear view of the original code flow.
Code morphing is also used to refer to the just-in-time compilation technology used in Transmeta processors such as the Crusoe and Efficeon to implement the x86 instruction set architecture.
Code morphing is often used in obfuscating the copy protection or other checks that a program makes to determine whether it is a valid, authentic installation, or an unauthorized copy, in order to make the removal of the copy-protection code more difficult than would otherwise be the case.
See also
Intermediate language
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https://en.wikipedia.org/wiki/TUN/TAP
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In computer networking, TUN and TAP are kernel virtual network devices. Being network devices supported entirely in software, they differ from ordinary network devices which are backed by physical network adapters.
The Universal TUN/TAP Driver originated in 2000 as a merger of the corresponding drivers in Solaris, Linux and BSD. The driver continues to be maintained as part of the Linux and FreeBSD kernels.
Design
Though both are for tunneling purposes, TUN and TAP can't be used together because they transmit and receive packets at different layers of the network stack. TUN, namely network TUNnel, simulates a network layer device and operates in layer 3 carrying IP packets. TAP, namely network TAP, simulates a link layer device and operates in layer 2 carrying Ethernet frames. TUN is used with routing. TAP can be used to create a user space network bridge.
Packets sent by an operating system via a TUN/TAP device are delivered to a user space program which attaches itself to the device. A user space program may also pass packets into a TUN/TAP device. In this case the TUN/TAP device delivers (or "injects") these packets to the operating-system network stack thus emulating their reception from an external source.
Applications
Virtual private networks
OpenVPN, Ethernet/IP over TCP/UDP; encrypted, compressed
ZeroTier, Ethernet/IP over TCP/UDP; encrypted, compressed, cryptographic addressing scheme
FreeLAN, open-source, free, multi-platform IPv4, IPv6 and peer-to-peer VPN software over UDP/IP.
n2n, an open source Layer 2 over Layer 3 VPN application which uses a peer-to-peer architecture for network membership and routing
Tinc, Ethernet/IPv4/IPv6 over TCP/UDP; encrypted, compressed
VTun, Ethernet/IP/serial/Unix pipe over TCP; encrypted, compressed, traffic-shaping
OpenSSH
coLinux, Ethernet/IP over TCP/UDP
Hamachi
OpenConnect
WireGuard
Tailscale
vtun
Virtual-machine networking
Bochs
coLinux
Hercules (S/390 emulator)
Open vSwitch
QEMU/KVM
User-
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https://en.wikipedia.org/wiki/Gr%C3%BCneisen%20parameter
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Grüneisen parameter is a dimensionless thermodynamic parameter named after German physicist Eduard Grüneisen, whose original definition was formulated in terms of the phonon nonlinearities.
Because of the equivalences of many properties and derivatives within thermodynamics (e.g. see Maxwell Relations), there are many formulations of the Grüneisen parameter which are equally valid, leading to numerous interpretations of its meaning. Some formulations for the Grüneisen parameter include:
where is volume, and are the principal (i.e. per-mass) heat capacities at constant pressure and volume, is energy, is entropy, is the volume thermal expansion coefficient, and are the adiabatic and isothermal bulk moduli, is the speed of sound in the medium, and is density. The Grüneisen parameter is dimensionless.
Grüneisen constant for perfect crystals with pair interactions
The expression for the Grüneisen constant of a perfect crystal with pair interactions in -dimensional space has the form:
where is the interatomic potential, is the equilibrium distance, is the space dimensionality. Relations between the Grüneisen constant and parameters of Lennard-Jones, Morse, and Mie potentials are presented in the table below.
The expression for the Grüneisen constant of a 1D chain with Mie potential exactly coincides with the results of MacDonald and Roy.
Using the relation between the Grüneisen parameter and interatomic potential one can derive the simple necessary and sufficient condition for Negative Thermal Expansion in perfect crystals with pair interactions A proper description of the Grüneisen parameter represents a stringent test for any type of interatomic potential.
Microscopic definition via the phonon frequencies
The physical meaning of the parameter can also be extended by combining thermodynamics with a reasonable microphysics model for the vibrating atoms within a crystal.
When the restoring force acting on an atom displaced from its equilibrium posi
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https://en.wikipedia.org/wiki/List%20of%20physical%20constants
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The constants listed here are known values of physical constants expressed in SI units; that is, physical quantities that are generally believed to be universal in nature and thus are independent of the unit system in which they are measured. Many of these are redundant, in the sense that they obey a known relationship with other physical constants and can be determined from them.
Table of physical constants
Uncertainties
While the values of the physical constants are independent of the system of units in use, each uncertainty as stated reflects our lack of knowledge of the corresponding value as expressed in SI units, and is strongly dependent on how those units are defined. For example, the atomic mass constant is exactly known when expressed using the dalton (its value is exactly 1 Da), but the kilogram is not exactly known when using these units, the opposite of when expressing the same quantities using the kilogram.
Technical constants
Some of these constants are of a technical nature and do not give any true physical property, but they are included for convenience. Such a constant gives the correspondence ratio of a technical dimension with its corresponding underlying physical dimension. These include the Boltzmann constant , which gives the correspondence of the dimension temperature to the dimension of energy per degree of freedom, and the Avogadro constant , which gives the correspondence of the dimension of amount of substance with the dimension of count of entities (the latter formally regarded in the SI as being dimensionless). By implication, any product of powers of such constants is also such a constant, such as the molar gas constant .
See also
List of mathematical constants
Physical constant
List of particles
Notes
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https://en.wikipedia.org/wiki/Bactritida
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The Bactritida are a small order of more or less straight-shelled (orthoconic) cephalopods that first appeared during the Emsian stage of the Devonian period (407 million years ago) with questionable origins in Pragian stage before 409 million years ago, and persisted until Carnian pluvial event in the upper middle Carnian stage of the Triassic period (231 million years ago). They are considered ancestors of the ammonoids, as well as of the coleoids (octopus, squid, cuttlefish, and the extinct belemnites).
Bactritids are distinguished from the more primitive nautiloids by the small size and globular shape of the protoconch, the so-called embryonic shell. Nautiloids have relatively large embryonic shells, and living species lay a few large eggs. In contrast, bactritids and ammonoids produced large numbers of small eggs, each housing a small embryonic shell.
Classification and description
Bactritida (Erben 1964) are characterized by orthoconic to cyrtoconic shells that may be long or short with a narrow siphuncle invariably in contact with the ventral wall and sutures uniformly with V-shaped ventral lobes. Septal necks are orthochoanitic to cyrtochoanitic, the apical angle may be small or large, and the protoconch is globular to egg-shaped. The Bactritida comprise two families, the Bactritidae and the Parabactritidae.
Bactritidae
The Bactritidae are characterized by long orthoconic to cyrtoconic shells with a small apical angle (less than 10°) and septal necks that are orthochoanitic. Chamber length is variable. The Bactritidae contain eight recognized genera. Bactrites has the longest range, from the Lower Devonian to the Upper Permian, and even possibly from the Silurian.
The Bactritidae gave rise to the Ammonoidea in the Early Devonian starting with an early Bactrites and going with increasingly tight curvature from Lobobactrites to Cyrtobactrites, leading to the gyroconic Anetoceras of the Anarcestida (Ammonoidea).
Parabactritidae
The Parabactritidae are ch
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https://en.wikipedia.org/wiki/Attribute%20domain
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In computing, the attribute domain is the set of values allowed in an attribute.
For example:
Rooms in hotel (1-300)
Age (1-99)
Married (yes or no)
Nationality (Nepalese, Indian, American, or British)
Colors (Red, Yellow, Green)
For the relational model it is a requirement that each part of a tuple be atomic. The consequence is that each value in the tuple must be of some basic type, like a string or an integer. For the elementary type to be atomic it cannot be broken into more pieces. Alas, the domain is an elementary type, and attribute domain the domain a given attribute belongs to an abstraction belonging to or characteristic of an entity.
For example, in SQL, one can create their own domain for an attribute with the command
CREATE DOMAIN SSN_TYPE AS CHAR(9) ;
The above command says : "Create a datatype SSN_TYPE that is of character type with size 9 "
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https://en.wikipedia.org/wiki/List%20of%20statistical%20software
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Statistical software are specialized computer programs for analysis in statistics and econometrics.
Open-source
ADaMSoft – a generalized statistical software with data mining algorithms and methods for data management
ADMB – a software suite for non-linear statistical modeling based on C++ which uses automatic differentiation
Chronux – for neurobiological time series data
DAP – free replacement for SAS
Environment for DeveLoping KDD-Applications Supported by Index-Structures (ELKI) a software framework for developing data mining algorithms in Java
Epi Info – statistical software for epidemiology developed by Centers for Disease Control and Prevention (CDC). Apache 2 licensed
Fityk – nonlinear regression software (GUI and command line)
GNU Octave – programming language very similar to MATLAB with statistical features
gretl – gnu regression, econometrics and time-series library
intrinsic Noise Analyzer (iNA) – For analyzing intrinsic fluctuations in biochemical systems
jamovi – A free software alternative to IBM SPSS Statistics
JASP – A free software alternative to IBM SPSS Statistics with additional option for Bayesian methods
JMulTi – For econometric analysis, specialised in univariate and multivariate time series analysis
Just another Gibbs sampler (JAGS) – a program for analyzing Bayesian hierarchical models using Markov chain Monte Carlo developed by Martyn Plummer. It is similar to WinBUGS
KNIME – An open source analytics platform built with Java and Eclipse using modular data pipeline workflows
LIBSVM – C++ support vector machine libraries
mlpack – open-source library for machine learning, exploits C++ language features to provide maximum performance and flexibility while providing a simple and consistent application programming interface (API)
Mondrian – data analysis tool using interactive statistical graphics with a link to R
Neurophysiological Biomarker Toolbox – Matlab toolbox for data-mining of neurophysiological biomarkers
OpenBUGS
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https://en.wikipedia.org/wiki/Schreier%20vector
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In mathematics, especially the field of computational group theory, a Schreier vector is a tool for reducing the time and space complexity required to calculate orbits of a permutation group.
Overview
Suppose G is a finite group with generating sequence which acts on the finite set . A common task in computational group theory is to compute the orbit of some element under G. At the same time, one can record a Schreier vector for . This vector can then be used to find an element satisfying , for any . Use of Schreier vectors to perform this requires less storage space and time complexity than storing these g explicitly.
Formal definition
All variables used here are defined in the overview.
A Schreier vector for is a vector such that:
For (the manner in which the are chosen will be made clear in the next section)
for
Use in algorithms
Here we illustrate, using pseudocode, the use of Schreier vectors in two algorithms
Algorithm to compute the orbit of ω under G and the corresponding Schreier vector
Input: ω in Ω,
for i in { 0, 1, …, n }:
set v[i] = 0
set orbit = { ω }, v[ω] = −1
for α in orbit and i in { 1, 2, …, r }:
if is not in orbit:
append to orbit
set
return orbit, v
Algorithm to find a g in G such that ωg = α for some α in Ω, using the v from the first algorithm
Input: v, α, X
if v[α] = 0:
return false
set g = e, and k = v[α] (where e is the identity element of G)
while k ≠ −1:
set
return g
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https://en.wikipedia.org/wiki/Help%20key
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A Help key, found in the shape of a dedicated key explicitly labeled , or as another key, typically one of the function keys, on a computer keyboard, is a key which, when pressed, produces information on the screen/display to aid the user in their current task, such as using a specific function in an application program.
In the case of a non-dedicated Help key, the location of the key will sometimes vary between different software packages. Most common in computer history, however, is the development of a de facto Help key location for each brand/family of computer, exemplified by the use of F1 on IBM compatible PCs.
Apple keyboards
On a full-sized Apple keyboard, the help key was labelled simply as , located to the left of the . Where IBM compatible PC keyboards had the , Apple keyboards had the help key instead. As of 2007, new Apple keyboards do not have a help key. In its place, a full-sized Apple keyboard has a instead. Instead of a mechanical help key, the menu bar for most applications contain a Help menu as a matter of convention.
Commodore and Amiga keyboards
The Commodore 128 had a key in the second block of top row keys. Amiga keyboards had a key, labelled as such, above the arrow keys on the keyboard, and next to a key (where the cluster is on a standard PC keyboard).
Atari keyboards
The keyboards of the Atari 16- and 32-bit computers had a key above the arrow keys on the keyboard. Atari 8-bit XL and XE series keyboards had dedicated keys, but in the group of differently-styled system keys separated from the rest of the keyboard.
Sun Microsystems (Oracle)
Most of the Sun Microsystems keyboards have a dedicate "" key in the left top corner (left from the "" key above block of 10 () extra keys.
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https://en.wikipedia.org/wiki/Base%20%28group%20theory%29
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Let be a finite permutation group acting on a set . A sequence
of k distinct elements of is a base for G if the only element of which fixes every pointwise is the identity element of .
Bases and strong generating sets are concepts of importance in computational group theory. A base and a strong generating set (together often called a BSGS) for a group can be obtained using the Schreier–Sims algorithm.
It is often beneficial to deal with bases and strong generating sets as these may be easier to work with than the entire group. A group may have a small base compared to the set it acts on. In the "worst case", the symmetric groups and alternating groups have large bases (the symmetric group Sn has base size n − 1), and there are often specialized algorithms that deal with these cases.
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https://en.wikipedia.org/wiki/Bind%20rune
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A bind rune or bindrune () is a Migration Period Germanic ligature of two or more runes. They are extremely rare in Viking Age inscriptions, but are common in earlier (Proto-Norse) and later (medieval) inscriptions.
On some runestones, bind runes may have been ornamental and used to highlight the name of the carver.
Description
There are two types of bind runes. Normal bind runes are formed of two (or rarely three) adjacent runes which are joined together to form a single conjoined glyph, usually sharing a common vertical stroke (see Hadda example below). Another type of bind rune called a same-stave rune, which is common in Scandinavian runic inscriptions but does not occur at all in Anglo-Saxon runic inscriptions, is formed by several runic letters written sequentially along a long common stemline (see þ=r=u=t=a=ʀ= =þ=i=a=k=n example shown in image). In the latter cases the long bind rune stemline may be incorporated into an image on the rune stone, for example as a ship's mast on runestones Sö 158 at Ärsta and Sö 352 in Linga, Södermanland, Sweden, or as the waves under a ship on DR 220 in Sønder Kirkeby, Denmark.
Examples
Elder futhark
Examples found in Elder Futhark inscriptions include:
Stacked Tiwaz runes: Kylver Stone, Seeland-II-C
Gebô runes combined with vowels: Kragehul I
The syllable ing written as a ligature of Isaz and Ingwaz (the so-called "lantern rune").
Anglo-Saxon Futhorc
Bind runes are not common in Anglo-Saxon inscriptions, but double ligatures do sometimes occur, and triple ligatures may rarely occur. The following are examples of bind-runes that have been identified in Anglo-Saxon runic inscriptions:
The word is written with a ligatured double (dd) on the Thornhill III rune-stone
The name is written with a ligatured double (dd) on the Derbyshire bone plate
The word is written with a ligatured and (er) on some Northumbrian stycas
The Latin word is written as with a ligatured and (mæ) on the Whitby comb
The inscription
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https://en.wikipedia.org/wiki/Cockade%20of%20Peru
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The cockade of Peru is a popular unofficial symbol of the Peruvian nation. While an 1825 law decreed its characteristics, there is no official regulation concerning its use, and it is not recognised as a national symbol in the Peruvian Constitution. It has the same colors as the national flag: red-white-red. It is often worn as a badge on the chest during Independence Day parades and other events of the day.
External links
Peru: symbols and customs, a review.
Peru
National symbols of Peru
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https://en.wikipedia.org/wiki/Lip%C3%B3t%20Fej%C3%A9r
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Lipót Fejér (or Leopold Fejér, ; 9 February 1880 – 15 October 1959) was a Hungarian mathematician of Jewish heritage. Fejér was born Leopold Weisz, and changed to the Hungarian name Fejér around 1900.
Biography
He was born in Pécs, Austria-Hungary, into the Jewish family of Victoria Goldberger and Samuel Weiss. His maternal great-grandfather Samuel Nachod was a doctor and his grandfather was a renowned scholar, author of a Hebrew-Hungarian dictionary. Leopold's father, Samuel Weiss, was a shopkeeper in Pecs. In primary schools Leopold was not doing well, so for a while his father took him away to home schooling. The future scientist developed his interest in mathematics in high school thanks to his teacher Sigismund Maksay.
Fejér studied mathematics and physics at the University of Budapest and at the University of Berlin, where he was taught by Hermann Schwarz. In 1902 he earned his doctorate from University of Budapest (today Eötvös Loránd University). From 1902 to 1905 Fejér taught there and from 1905 until 1911 he taught at Franz Joseph University in Kolozsvár in Austria-Hungary (now Cluj-Napoca in Romania). In 1911 Fejér was appointed to the chair of mathematics at the University of Budapest and he held that post until his death. He was elected corresponding member (1908), member (1930) of the Hungarian Academy of Sciences.
During his period in the chair at Budapest Fejér led a highly successful Hungarian school of analysis. He was the thesis advisor of mathematicians such as John von Neumann, Paul Erdős, George Pólya and Pál Turán. Thanks to Feuer, Hungary has developed a strong mathematical school: he has educated a new generation of students who have gone on to become eminent scientists. As Poya recalled, a large number of them became interested in mathematics thanks to Fejér, his fascinating personality and charisma. Fejér gave short (no more than an hour) but very entertaining lectures and often sat with students in cafés, discussing mathematical prob
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https://en.wikipedia.org/wiki/Extension%20%28predicate%20logic%29
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The extension of a predicatea truth-valued functionis the set of tuples of values that, used as arguments, satisfy the predicate. Such a set of tuples is a relation.
Examples
For example, the statement "d2 is the weekday following d1" can be seen as a truth function associating to each tuple (d2, d1) the value true or false. The extension of this truth function is, by convention, the set of all such tuples associated with the value true, i.e.
{(Monday, Sunday),
(Tuesday, Monday),
(Wednesday, Tuesday),
(Thursday, Wednesday),
(Friday, Thursday),
(Saturday, Friday),
(Sunday, Saturday)}
By examining this extension we can conclude that "Tuesday is the weekday following Saturday" (for example) is false.
Using set-builder notation, the extension of the n-ary predicate can be written as
Relationship with characteristic function
If the values 0 and 1 in the range of a characteristic function are identified with the values false and true, respectivelymaking the characteristic function a predicate, then for all relations R and predicates the following two statements are equivalent:
is the characteristic function of R
R is the extension of
See also
Extensional logic
Extensional set
Extensionality
Intension
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https://en.wikipedia.org/wiki/Posterior%20cutaneous%20nerve%20of%20thigh
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The posterior cutaneous nerve of the thigh (also called the posterior femoral cutaneous nerve) is a sensory nerve of the thigh. It is a branch of the sacral plexus. It supplies the skin of the posterior surface of the thigh, leg, buttock, and also the perineum.
Unlike most nerves termed "cutaneous" which are subcutaneous, only the terminal branches of this nerve pass into subcutaneous tissue before being distributed to the skin, with most of the nerve itself situated deep to the deep fascia.
Structure
Origin
The posterior cutaneous nerve of the thigh is a branch of the sacral plexus. It arises from the posterior divisions of the S1-S2, and the anterior divisions of S2-S3 sacral spinal nerves.
Course
It leaves the pelvis through the greater sciatic foramen inferior to the piriformis muscle. It then descends deep to the gluteus maximus muscle, medial or posterior to the sciatic nerve, and alongside the inferior gluteal artery. It descends within the posterior thigh deep to the fascia lata (the deep fascia of the thigh) and superficial to the hamstring muscles. It runs over the long head of the biceps femoris to the back of the knee. It pierces the fascia lata posterior to the knee. It then accompanies the small saphenous vein to about the middle of the posterior leg (i.e. lower leg). Its terminal branches communicate with the sural nerve.
Branches
Its branches are all cutaneous, and are distributed to the gluteal region, the perineum, and the back of the thigh and leg.
The inferior clunial nerves (or gluteal branches), three or four in number, turn upward around the lower border of the gluteus maximus, and supply the skin covering the lower and lateral part of that muscle.
The perineal branches are distributed to the skin at the upper and medial side of the thigh.
The main part to the back of the thigh and leg consists of numerous filaments derived from both sides of the nerve, and distributed to the skin covering the back and medial side of the thigh, the
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https://en.wikipedia.org/wiki/Inferior%20gluteal%20nerve
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The inferior gluteal nerve is the main motor neuron that innervates the gluteus maximus muscle. It is responsible for the movement of the gluteus maximus in activities requiring the hip to extend the thigh, such as climbing stairs. Injury to this nerve is rare but often occurs as a complication of posterior approach to the hip during hip replacement. When damaged, one would develop gluteus maximus lurch, which is a gait abnormality which causes the individual to 'lurch' backwards to compensate lack in hip extension.
Anatomy
The largest muscle of the posterior hip, gluteus maximus, is innervated by the inferior gluteal nerve.
It branches out and then enters the deep surface of the gluteus maximus, the principal extensor of the thigh, and supplies it.
Origin
The muscle is supplied by the inferior gluteal nerve which arises from the dorsal branches of the ventral rami of the fifth (L5), the first (S1) and second (S2) sacral nerves.
The lumbosacral trunk, which is made up of L5 and a small branch of L4, effectively connects the lumbar and sacral plexuses. The lower branches of the L4 and the L5 nerves enter the sacral plexus.
The sacral plexus is formed by the lumbosacral trunk, the first to third sacral ventral rami, and part of the fourth, the remainder of the last joining the coccygeal plexus. The sacral plexus is formed in the pelvis in front of the piriformis muscle.
The sacral plexus is formed anterior to the piriformis muscle and gives rise to the sciatic nerve, the superior and inferior gluteal nerves, and the pudendal and posterior femoral cutaneous nerves.
However, most of the sacral plexus nerves are scarcely recognizable, because they leave the pelvis through the greater sciatic foramen. From the pelvis, the anterior primary branches of the nerves entering the plexus (the first sacral nerve being a particularly large one) and a mass of nerves on the piriformis can be recognized.
Course
The inferior gluteal nerve leaves the pelvis through the greater
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https://en.wikipedia.org/wiki/Superior%20gluteal%20nerve
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The superior gluteal nerve is a mixed (motor and sensory) nerve of the sacral plexus that originates in the pelvis. It provides motor innervation to the gluteus medius, gluteus minimus, tensor fasciae latae, and piriformis muscles; it also has a cutaneous branch.
Structure
Origin
The superior gluteal nerve originates in the sacral plexus. It arises from the posterior divisions of L4, L5 and S1.
Course
It exits the pelvis through the greater sciatic foramen superior to the piriformis muscle. It is accompanied by the superior gluteal artery and the superior gluteal vein.
It passes lateral-ward in between the gluteus medius muscle and the gluteus minimus muscle, accompanied by the deep branch of the superior gluteal artery. It divides into a superior branch and an inferior branch.
The inferior branch continues to pass between the two muscles to end in the tensor fasciae latae muscle.
Distribution
Motor
tensor fasciae latae muscle
gluteus medius muscle (superior branch and inferior branch)
gluteus minimus muscle (inferior branch, sometimes superior branch as well)
piriformis muscle
Sensory
The superior gluteal nerve also has a cutaneous branch.
Clinical significance
Gait
In normal gait, the small gluteal muscles on the stance side can stabilize the pelvis in the coronal plane. Weakness or paralysis of these muscles caused by a damaged superior gluteal nerve can result in a weak abduction in the affected hip joint. This gait disturbance is known as Trendelenburg gait. In a positive Trendelenburg's sign the pelvis sags toward the normal unsupported side (the swing leg). The opposite, when the pelvis is elevated on the swing side, is known as Duchenne limp. Bilateral loss of the small gluteal muscles results in a waddling gait.
Iatrogenic damage
The superior gluteal nerve may be damaged by intramuscular injections and nephrectomy.
See also
Inferior gluteal nerve
Trendelenburg's sign
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https://en.wikipedia.org/wiki/Asemic%20writing
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Asemic writing is a wordless open semantic form of writing. The word asemic means "having no specific semantic content", or "without the smallest unit of meaning". With the non-specificity of asemic writing there comes a vacuum of meaning, which is left for the reader to fill in and interpret. All of this is similar to the way one would deduce meaning from an abstract work of art. Where asemic writing distinguishes itself among traditions of abstract art is in the asemic author's use of gestural constraint, and the retention of physical characteristics of writing such as lines and symbols. Asemic writing is a hybrid art form that fuses text and image into a unity, and then sets it free to arbitrary subjective interpretations. It may be compared to free writing or writing for its own sake, instead of writing to produce verbal context. The open nature of asemic works allows for meaning to occur across linguistic understanding; an asemic text may be "read" in a similar fashion regardless of the reader's natural language. Multiple meanings for the same symbolism are another possibility for an asemic work, that is, asemic writing can be polysemantic or have zero meaning, infinite meanings, or its meaning can evolve over time. Asemic works leave for the reader to decide how to translate and explore an asemic text; in this sense, the reader becomes co-creator of the asemic work.
In 1997, visual poets Tim Gaze and Jim Leftwich first applied the word asemic to name their quasi-calligraphic writing gestures. They then began to distribute them to poetry magazines both online and in print. The authors explored sub-verbal and sub-letteral forms of writing, and textual asemia as a creative option and as an intentional practice. Since the late 1990s, asemic writing has blossomed into a worldwide literary/art movement. It has especially grown in the early part of the 21st century, though there is an acknowledgement of a long and complex history, which precedes the activities of t
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https://en.wikipedia.org/wiki/Pulmonary%20consolidation
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A pulmonary consolidation is a region of normally compressible lung tissue that has filled with liquid instead of air. The condition is marked by induration (swelling or hardening of normally soft tissue) of a normally aerated lung. It is considered a radiologic sign. Consolidation occurs through accumulation of inflammatory cellular exudate in the alveoli and adjoining ducts. The liquid can be pulmonary edema, inflammatory exudate, pus, inhaled water, or blood (from bronchial tree or hemorrhage from a pulmonary artery). Consolidation must be present to diagnose pneumonia: the signs of lobar pneumonia are characteristic and clinically referred to as consolidation.
Signs
Signs that consolidation may have occurred include:
Expansion of the thorax on inspiration is reduced on the affected side
Vocal fremitus is increased on the affected side
Percussion note is impaired in the affected area
Breath sounds are bronchial
Possible medium, late, or pan-inspiratory crackles
Vocal resonance is increased. Here, the patient's voice (or whisper, as in whispered pectoriloquy) can be heard more clearly when there is consolidation, as opposed to the healthy lung where speech sounds muffled.
A pleural rub may be present.
A lower PAO2 than calculated in the alveolar gas equation
Diagnosis
Radiology
Typically, an area of white lung is seen on a standard X-ray. Consolidated tissue is more radio-opaque than normally aerated lung parenchyma, so that it is clearly demonstrable in radiography and on CT scans. Consolidation is often a middle-to-late stage feature/complication in pulmonary infections.
See also
Pulmonary infiltrate
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https://en.wikipedia.org/wiki/Marcus%20du%20Sautoy
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Marcus Peter Francis du Sautoy (; born 26 August 1965) is a British mathematician, Simonyi Professor for the Public Understanding of Science at the University of Oxford, Fellow of New College, Oxford and author of popular mathematics and popular science books. He was previously a fellow of All Souls College, Oxford, Wadham College, Oxford and served as president of the Mathematical Association, an Engineering and Physical Sciences Research Council (EPSRC) senior media fellow, and a Royal Society University Research Fellow.
In 1996, he was awarded the title of distinction of Professor of Mathematics.
Education and early life
Du Sautoy was born in London to Bernard du Sautoy, employed in the computer industry, and Jennifer ( Deason) du Sautoy, who left the Foreign Office to raise her children. He grew up in Henley-on-Thames. His grandfather, Peter du Sautoy, was chairman of the publisher Faber and Faber, and managed the estates of James Joyce and Samuel Beckett.
Du Sautoy was educated at Gillotts Comprehensive School and King James's Sixth Form College (now Henley College) and Wadham College, Oxford, where he was awarded a first class honours degree in mathematics. In 1991 he completed a doctorate in mathematics on discrete groups, analytic groups and Poincaré series, supervised by Dan Segal.
Career and research
Du Sautoy's research "uses classical tools from number theory to explore the mathematics of symmetry". Du Sautoy's academic work concerns mainly group theory and number theory.
Du Sautoy is known for his work popularising mathematics, and has been named by The Independent on Sunday as one of the UK's leading scientists. He has also served on the advisory board of
Mangahigh.com, an online maths game website. He is a regular contributor to the BBC Radio 4's In Our Time programme and has written for The Times and The Guardian. He has written numerous academic articles and books on mathematics, the most recent being an exploration of the current state
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https://en.wikipedia.org/wiki/Articularis%20genus%20muscle
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The articularis genus (also known as the subcrureus muscle) is a small skeletal muscle located anteriorly on the thigh just above the knee.
Structure
It arises from the anterior surface of the lower part of the body of the femur, deep to the vastus intermedius, close to the knee and from the deep fibers of the vastus intermedius.
Its insertion is on the synovial membrane of the knee-joint.
Blood supply
It is supplied by the lateral femoral circumflex artery.
Innervation
It is innervated by branches of the femoral nerve (L2-L4).
Variation
Flat, wispy and highly variable, sometimes consisting of several separate muscular bundles, this muscle is without a distinct investing fascia and ranges 1.5–3 cm in width.
It is usually distinct from the vastus intermedius, but occasionally blended with it.
Function
Articularis genus pulls the suprapatellar bursa superiorly during extension of the knee, and prevents impingement of the synovial membrane between the patella and the femur.
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https://en.wikipedia.org/wiki/Genetic%20equilibrium
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Genetic equilibrium is the condition of an allele or genotype in a gene pool (such as a population) where the frequency does not change from generation to generation. Genetic equilibrium describes a theoretical state that is the basis for determining whether and in what ways populations may deviate from it. Hardy–Weinberg equilibrium is one theoretical framework for studying genetic equilibrium. It is commonly studied using models that take as their assumptions those of Hardy-Weinberg, meaning:
No gene mutations occurring at that locus or the loci associated with the trait
A large population size
Limited-to-no immigration, emigration, or migration (genetic flow)
No natural selection on that locus or trait
Random mating (panmixis)
It can describe other types of equilibrium as well, especially in modeling contexts. In particular, many models use a variation of the Hardy–Weinberg principle as their basis. Instead of all of the Hardy–Weinberg characters being present, these instead assume a balance between the diversifying effects of genetic drift and the homogenizing effects of migration between populations. A population not at equilibrium suggests that one of the assumptions of the model in question has been violated.
Theoretical models of genetic equilibrium
The Hardy–Weinberg principle provides the mathematical framework for genetic equilibrium. Genetic equilibrium itself, whether Hardy-Weinberg or otherwise, provides the groundwork for a number of applications, in including population genetics, conservation and evolutionary biology. With the rapid increase in whole genome sequences available as well as the proliferation of anonymous markers, models have been used to extend the initial theory to all manner of biological contexts. Using data from genetic markers such as ISSRs and RAPDs as well as the predictive potential of statistics, studies have developed models to infer what processes drove the lack of equilibrium. This includes local adaptation, range contr
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https://en.wikipedia.org/wiki/Oogamy
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Oogamy is a form of anisogamy where the gametes differ in both size and form.
In oogamy the large female gamete (also known as ovum) is immotile, while the small male gamete (also known as sperm) is mobile. Oogamy is a common form of anisogamy, with almost all animals and land plants being oogamous.
Oogamy is found in most sexually reproducing species, including all vertebrates, land plants, and some algae. The ancestral state of sexual reproduction is believed to be isogamy, with oogamy evolving through anisogamy. Once oogamy evolves, males and females typically differ in various aspects. Internal fertilization may have originated from oogamy, although some studies suggest that oogamy in certain species may have evolved before the transition from external to internal fertilization. In streptophytes, oogamy occurred before the split from green algae.
Occurrence
Oogamy is found in almost all animal species that reproduce sexually. There are exceptions, such as the opiliones that have immobile sperm.
Oogamy is found in all land plants, and in some red algae, brown algae and green algae. Oogamy is favored in land plants because only one gamete has to travel through harsh environments outside the plant. Oogamy is also present in oomycetes.
Etymology
The term oogamy was first used in the year 1888.
Evolution
It is generally accepted that isogamy is the ancestral state and that oogamy evolves from isogamy through anisogamy. When oogamy has evolved, males and females typically differ in many aspects. Oogamy evolved before the transition from external to internal fertilization.
In streptophytes, oogamy occurred before the split from green algae.
See also
Gamete
Anisogamy
Isogamy
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https://en.wikipedia.org/wiki/Canonical%20quantum%20gravity
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In physics, canonical quantum gravity is an attempt to quantize the canonical formulation of general relativity (or canonical gravity). It is a Hamiltonian formulation of Einstein's general theory of relativity. The basic theory was outlined by Bryce DeWitt in a seminal 1967 paper, and based on earlier work by Peter G. Bergmann using the so-called canonical quantization techniques for constrained Hamiltonian systems invented by Paul Dirac. Dirac's approach allows the quantization of systems that include gauge symmetries using Hamiltonian techniques in a fixed gauge choice. Newer approaches based in part on the work of DeWitt and Dirac include the Hartle–Hawking state, Regge calculus, the Wheeler–DeWitt equation and loop quantum gravity.
Canonical quantization
In the Hamiltonian formulation of ordinary classical mechanics the Poisson bracket is an important concept. A "canonical coordinate system" consists of canonical position and momentum variables that satisfy canonical Poisson-bracket relations,
where the Poisson bracket is given by
for arbitrary phase space functions and . With the use of Poisson brackets, the Hamilton's equations can be rewritten as,
These equations describe a "flow" or orbit in phase space generated by the Hamiltonian . Given any phase space function , we have
In canonical quantization the phase space variables are promoted to quantum operators on a Hilbert space and the Poisson bracket between phase space variables is replaced by the canonical commutation relation:
In the so-called position representation this commutation relation is realized by the choice:
and
The dynamics are described by Schrödinger equation:
where is the operator formed from the Hamiltonian with the replacement and .
Canonical quantization with constraints
Canonical classical general relativity is an example of a fully constrained theory. In constrained theories there are different kinds of phase space: the unrestricted (also called kinematic) phase spa
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https://en.wikipedia.org/wiki/Abductor%20digiti%20minimi%20muscle%20of%20foot
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The abductor digiti minimi (abductor minimi digiti, abductor digiti quinti) is a muscle which lies along the lateral (outer) border of the foot, and is in relation by its medial margin with the lateral plantar artery, vein and nerves.
Its homolog in the arm is the abductor digiti minimi muscle in the hand.
Origin and insertion
It arises, by a broad origin, from the lateral process of the tuberosity of the calcaneus, from the under surface of the calcaneus between the two processes of the tuberosity, from the forepart of the medial process, from the plantar aponeurosis, and from the intermuscular septum between it and the flexor digitorum brevis.
Its tendon, after gliding over a smooth facet on the under surface of the base of the fifth metatarsal bone, is inserted, with the flexor digiti quinti brevis, into the fibular side of the base of the first phalanx of the fifth toe.
Innervation
The abductor digiti minimi is innervated by the lateral plantar nerve, a branch of the tibial nerve.
Function
Its function is flexion and abduction of the fifth (little) toe at the metatarsophalangeal joint.
Clinical relevance
Due to its role in posture during all physical activity while in an upright position, the abductor digiti minimi is often the target of injury.
In case of polydactyly it may insert to the sixth toe instead, if there is one.
Etymology
The Latin name abductor digiti minimi translates to abductor of the small digit while the alternative name abductor digiti quinti means abductor of fifth digit.
Additional images
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https://en.wikipedia.org/wiki/Flexor%20digiti%20minimi%20brevis%20muscle%20of%20foot
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The Flexor digiti minimi brevis (Flexor brevis minimi digiti, Flexor digiti quinti brevis) lies under the metatarsal bone on the little toe, and resembles one of the Interossei.
It arises from the base of the fifth metatarsal bone, and from the sheath of the Fibularis longus; its tendon is inserted into the lateral side of the base of the first phalanx of the fifth toe.
Occasionally a few of the deeper fibers are inserted into the lateral part of the distal half of the fifth metatarsal bone; these are described by some as a distinct muscle, the opponens digiti quinti.
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https://en.wikipedia.org/wiki/Dorsal%20interossei%20of%20the%20hand
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In human anatomy, the dorsal interossei (DI) are four muscles in the back of the hand that act to abduct (spread) the index, middle, and ring fingers away from hand's midline (ray of middle finger) and assist in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints of the index, middle and ring fingers.
Structure
There are four dorsal interossei in each hand. They are specified as 'dorsal' to contrast them with the palmar interossei, which are located on the anterior side of the metacarpals.
The dorsal interosseous muscles are bipennate, with each muscle arising by two heads from the adjacent sides of the metacarpal bones, but more extensively from the metacarpal bone of the finger into which the muscle is inserted. They are inserted into the bases of the proximal phalanges and into the extensor expansion of the corresponding extensor digitorum tendon. The middle digit has two dorsal interossei insert onto it while the first digit (thumb) and the fifth digit (little finger) have none. Each finger is provided with two interossei (palmar or dorsal), with the exception of the little finger, in which the abductor digiti minimi muscle takes the place of one of the dorsal interossei.
The first dorsal interosseous muscle is larger than the others. Between its two heads, the radial artery passes from the back of the hand into the palm. Between the heads of dorsal interossei two, three, and four, a perforating branch from the deep palmar arch is transmitted.
Origins and insertions
Proximal and distal interossei
With some individual variations, the interossei muscles are attached either proximally or distally on the extensor expansion. The first dorsal interosseous, the most consistent, is inserted entirely into the base of its proximal phalanx and the extensor hood there. The second, third, and fourth dorsal interossei have insertions both proximally on the base of the metacarpal and hood, and distally on the lateral bands and cent
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https://en.wikipedia.org/wiki/Clipper%20%28electronics%29
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In electronics, a clipper is a circuit designed to prevent a signal from exceeding a predetermined reference voltage level. A clipper does not distort the remaining part of the applied waveform. Clipping circuits are used to select, for purposes of transmission, that part of a signal waveform which lies above or below the predetermined reference voltage level.
Clipping may be achieved either at one level or two levels. A clipper circuit can remove certain portions of an arbitrary waveform near the positive or negative peaks or both. Clipping changes the shape of the waveform and alters its spectral components.
A clipping circuit consists of linear elements like resistors and non-linear elements like diodes or transistors, but it does not contain energy-storage elements like capacitors.
Clipping circuits are also called slicers or amplitude selectors.
Types
Diode clipper
A simple diode clipper can be made with a diode and a resistor. This will remove either the positive, or the negative half of the waveform depending on the direction the diode is connected. The simple circuit clips at zero voltage (or to be more precise, at the small forward voltage of the forward biased diode) but the clipping voltage can be set to any desired value with the addition of a reference voltage. The diagram illustrates a positive reference voltage but the reference can be positive or negative for both positive and negative clipping giving four possible configurations in all.
The simplest circuit for the voltage reference is a resistor potential divider connected between the voltage rails. This can be improved by replacing the lower resistor with a zener diode with a breakdown voltage equal to the required reference voltage. The zener acts as a voltage regulator stabilising the reference voltage against supply and load variations.
Zener diode
In the example circuit on the right, two zener diodes are used to clip the voltage VIN. The voltage in either direction is limited t
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https://en.wikipedia.org/wiki/Glabellar%20reflex
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The glabellar reflex, also known as the "glabellar tap sign", is a primitive reflex elicited by repetitive tapping of the the smooth part of the forehead above the nose and between the eyebrows. Subjects respond to the first several taps by blinking; if tapping were to then be made to persist, in cognitively intact individuals this would lead to habituation and consequent suppression of blinking. If instead the blinking were to persist along with the tapping, this is known as Myerson's sign, and is abnormal and a sign of frontal release; it is often seen in people who have Parkinson's disease.
The afferent sensory signals are transmitted by the trigeminal nerve to the brain stem; the efferent signals go to the orbicularis oculi muscle via the facial nerve, causing the muscle to reflexively contract, yielding blinking.
This reflex was first identified by Walker Overend.
See also
Glabella
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https://en.wikipedia.org/wiki/Ribotyping
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Ribotyping is a molecular technique for bacterial identification and characterization that uses information from rRNA-based phylogenetic analyses. It is a rapid and specific method widely used in clinical diagnostics and analysis of microbial communities in food, water, and beverages.
All bacteria have ribosomal genes, but the exact sequence is unique to each species, serving as a genetic fingerprint. Therefore, sequencing the particular 16S gene and comparing it to a database would yield identification of the particular species.
Technique
Ribotyping involves the digestion of bacterial genomic DNA with specific restriction enzymes. Each restriction enzyme cuts DNA at a specific nucleotide sequence, resulting in fragments of different lengths.
Those fragments are then run on a Gel electrophoresis, where they are separated according to size: the application of electrical field to the gel in which they are suspended causes the movement of DNA fragments (all negatively charged due to the presence of phosphate groups) through a matrix towards the positively charged end of the field. Small fragments move more easily and rapidly through the matrix, reaching a bigger distance from the starting position than larger fragments.
Following the separation in the gel matrix, the DNA fragments are moved onto nylon membranes and hybridized with a labelled 16S or 23S rRNA probe. This way only the fragments coding for such rRNA are visualised and can be analyzed. The pattern is then digitized and used to identify the origin of the DNA by a comparison with reference organisms in a computer database.
Conceptually, ribotyping is similar to probing restriction fragments of chromosomal DNA with cloned probes (randomly cloned probes or probes derived from a specific coding sequence such as that of a virulence factor).
See also
Genotyping
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https://en.wikipedia.org/wiki/Body%20fat%20percentage
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The body fat percentage (BFP) of a human or other living being is the total mass of fat divided by total body mass, multiplied by 100; body fat includes essential body fat and storage body fat. Essential body fat is necessary to maintain life and reproductive functions. The percentage of essential body fat for women is greater than that for men, due to the demands of childbearing and other hormonal functions. Storage body fat consists of fat accumulation in adipose tissue, part of which protects internal organs in the chest and abdomen. A number of methods are available for determining body fat percentage, such as measurement with calipers or through the use of bioelectrical impedance analysis.
The body fat percentage is a measure of fitness level, since it is the only body measurement which directly calculates a person's relative body composition without regard to height or weight. The widely used body mass index (BMI) provides a measure that allows the comparison of the adiposity of individuals of different heights and weights. While BMI largely increases as adiposity increases, due to differences in body composition, other indicators of body fat give more accurate results; for example, individuals with greater muscle mass or larger bones will have higher BMIs. As such, BMI is a useful indicator of overall fitness for a large group of people, but a poor tool for determining the health of an individual.
Typical body fat amounts
Epidemiologically, the percentage of body fat in an individual varies according to sex and age. Various theoretical approaches exist on the relationships between body fat percentage, health, athletic capacity, etc. Different authorities have consequently developed different recommendations for ideal body fat percentages.
This graph from the National Health and Nutrition Examination Survey (NHANES) in the United States charts the average body fat percentages of Americans from samples from 1999 to 2004:
In males, mean percentage body fat
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https://en.wikipedia.org/wiki/Serine%20octamer%20cluster
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The Serine octamer cluster in physical chemistry is an unusually stable cluster consisting of eight serine molecules (Ser) implicated in the origin of homochirality. This cluster was first discovered in mass spectrometry experiments. Electrospray ionization of an aerosol of serine in methanol results in a mass spectrum with a prominent ion peak of 841 corresponding to the Ser8+H+ cation. The smaller and larger clusters are virtually absent in the spectrum and therefore the number 8 is called a magic number. The same octamer ions are also produced by rapid evaporation of a serine solution on a hot (200-250 °C) metal surface or by sublimation of solid serine. After production, detection again is by mass-spectroscopic means. For the discussion of homochirality, these laboratory production methods are designed to mimic prebiotic conditions.
The cluster is not only unusually stable but also unusual because the clusters have a strong homochiral preference. A racemic serine solution produces a minimum amount of cluster and with solutions of both enantiomers a maximum amount is formed of both homochiral D-Ser8 and L-Ser8. In another experiment cluster formation of a racemic mixture with deuterium enriched L-serine results in a product distribution with hardly any 50/50 D/L clusters but a preference for either D or L enantioenriched clusters.
A model for chiral amplification is proposed whereby enantioenriched clusters are formed from a non-racemic mixture already enriched by L-serine as a result of a mirror-symmetry breaking process. Cluster formation is followed by isolation and on subsequent dissociation of the cluster a serene solution forms with a higher concentration of L-serine than in the original mixture. A cycle can be maintained in which each turn results in an incremental enrichment in L-serine. Many such cycles eventually result in enantiopure L-serine. This model has been experimentally verified.
Chiral transmission is assumed to take place through so-calle
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https://en.wikipedia.org/wiki/Urine
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Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.
Cellular metabolism generates many by-products that are rich in nitrogen and must be cleared from the bloodstream, such as urea, uric acid, and creatinine. These by-products are expelled from the body during urination, which is the primary method for excreting water-soluble chemicals from the body. A urinalysis can detect nitrogenous wastes of the mammalian body.
Urine plays an important role in the earth's nitrogen cycle. In balanced ecosystems, urine fertilizes the soil and thus helps plants to grow. Therefore, urine can be used as a fertilizer. Some animals use it to mark their territories. Historically, aged or fermented urine (known as lant) was also used for gunpowder production, household cleaning, tanning of leather and dyeing of textiles.
Human urine and feces are collectively referred to as human waste or human excreta, and are managed via sanitation systems. Livestock urine and feces also require proper management if the livestock population density is high.
Physiology
Most animals have excretory systems for elimination of soluble toxic wastes. In humans, soluble wastes are excreted primarily by the urinary system and, to a lesser extent in terms of urea, removed by perspiration. The urinary system consists of the kidneys, ureters, urinary bladder, and urethra. The system produces urine by a process of filtration, reabsorption, and tubular secretion. The kidneys extract the soluble wastes from the bloodstream, as well as excess water, sugars, and a variety of other compounds. The resulting urine contains high concentrations of urea and other substances, including toxins. Urine flows from the kidneys through the ureter, bladder, and finally the urethra before passing from the body.
Duration
Research looking at the duration
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https://en.wikipedia.org/wiki/Push%E2%80%93pull%20converter
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A push–pull converter is a type of DC-to-DC converter, a switching converter that uses a transformer to change the voltage of a DC power supply. The distinguishing feature of a push-pull converter is that the transformer primary is supplied with current from the input line by pairs of transistors in a symmetrical push-pull circuit. The transistors are alternately switched on and off, periodically reversing the current in the transformer. Therefore, current is drawn from the line during both halves of the switching cycle. This contrasts with buck-boost converters, in which the input current is supplied by a single transistor which is switched on and off, so current is drawn from the line during only a part of the switching cycle. During the remainder of the cycle, the output power is supplied by energy stored in inductors or capacitors in the power supply. Push–pull converters have steadier input current, create less noise on the input line, and are more efficient in higher power applications.
Circuit
Conceptual schematic of a full-bridge converter. This is not a center tapped or split primary push-pull converter.
The term push–pull is sometimes used to generally refer to any converter with bidirectional excitation of the transformer. For example, in a full-bridge converter, the switches (connected as an H-bridge) alternate the voltage across the supply side of the transformer, causing the transformer to function as it would for AC power and produce a voltage on its output side. However, push–pull more commonly refers to a two-switch topology with a split primary winding.
In any case, the output is then rectified and sent to the load. Capacitors are often included at the output to filter the switching noise.
In practice, it is necessary to allow a small interval between powering the transformer one way and powering it the other: the “switches” are usually pairs of transistors (or similar devices), and were the two transistors in the pair to switch simulta
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https://en.wikipedia.org/wiki/Odell%20Down%20Under
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Odell Down Under is a 1994 game for Microsoft Windows and Classic Mac OS that takes place in the Great Barrier Reef of Australia. Released by MECC, it is the sequel to Odell Lake.
History
Odell Down Under was released alongside a re-release of its companion game, Odell Lake. The game was recommended for ages 9 to adult.
The game was generally praised; School Library Journal cited the "realistic and beautiful" graphics and detailed field guide as strengths, while Booklist called it a "marvelous introduction to life in a thriving underwater community." The game was a finalist for MacUser's 1994 Editor's Choice Award for Children's Software.
Gameplay
The player takes on the role of a fish who in turn must eat, stay clean and avoid being eaten by predators to survive. There are several modes of gameplay. In Tournament mode, the player plays every fish in the game, starting as the tiny silver sprat and eventually reaching the great white shark. A shorter Challenge mode picks four random fish (from smallest to largest) instead. The player can choose to play any fish in Practice Mode.
Finally, in Create-A-Fish the player creates their own species based on various parameters such as size and agility, which also affect the appearance of the fish. The color, special ability, and nocturnal or diurnal habits are also selected. Special moves, also present for some 'real' fish, include the stingray's sting and the cuttlefish's ink squirt.
Each fish has different preferences for food, as described in the educational summary before the game starts. The game consists of nine screens, arranged in three levels from the sandy bottom to the reef's top, that various fish, including the player, move through looking for food. To survive, or to gain enough points to reach the next fish, the player's fish has to find enough food (which can include plants, crustaceans or coral as well as fish) to prevent its constantly decreasing energy bar from reaching 0 and death. The other main conce
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https://en.wikipedia.org/wiki/MDL%20Chime
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MDL Chime was a free plugin used by web browsers to display the three-dimensional structures of molecules. and was based on the RasMol code.
Chime was used by a wide range of biochemistry web sites for the visualization of macromolecules, many of which were linked to the World Index of Molecular Visualization Resources MolVisIndex.Org. Chime was also used until 2006 at the Protein Data Bank to examine structures stored there.
Although available in 1996 in both Windows 95 and classic Mac OS versions for both Netscape and Internet Explorer browsers, development of Chime did not follow the move to Mac OS X for the Mac and support for Windows-based browsers other than Internet Explorer was limited (although it works well in Mozilla Firefox). One significant feature added in 1997 was the ability to display spectroscopic data in the form of the IUPAC JCAMP-DX protocols. Apart from this, most subsequent updates were for the installation package to follow the development of Windows and Internet Explorer. Accelrys announced in 2012 that Chime was no longer supported and would remain available for download until the end of 2012. Chime was part of the ISIS product line acquired by Symyx Technologies from scientific publisher Elsevier in October 2007. Now Chime is owned by Dassault Systemes BIOVIA (formerly Accelrys), and has been merged into Discovery Studio, but no longer exists as a free browser plugin.
Chime largely has been superseded by Jmol, a non-proprietary open-source Java molecular visualization application and JavaScript applet that has maintained most Chime command compatibility while adding numerous features.
See also
List of molecular graphics systems
ISIS/Draw
Molecular graphics
Discovery Studio
RasMol
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https://en.wikipedia.org/wiki/Hexachloroacetone
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Hexachloroacetone is an organic compound with the formula (Cl3C)2CO. It is also called hexachloropropanone or perchloroacetone. Numbers indicating the position of the chlorine-atoms are generally omitted as all the possible positions are substituted with chlorine. It is a colorless liquid, slightly soluble in water.
Reactions and uses
Hexachloroacetone functions equivalently to trichloroacetyl chloride, i.e. as an trichloroacetylating agent.
The main use of hexachloroacetone is as a pesticide. For the use of hexachloroacetone in the preparation of a novel insect repellent see Perkow reaction. The industrial route to hexafluoroacetone involves treatment of hexachloroacetone with HF:
(CCl3)2CO + 6 HF → (CF3)2CO + 6 HCl
See also
Chloroacetone
Dichloroacetone
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https://en.wikipedia.org/wiki/LCD%20Smartie
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LCD Smartie is open-source software for Microsoft Windows which allows a character LCD to be used as an auxiliary display device for a PC. Supported devices include displays based on the Hitachi HD44780 LCD controller, the Matrix Orbital Serial/USB LCD, and Palm OS devices (when used in conjunction with PalmOrb). The program has built in support for many systems statistics (i.e. cpu load, network utilization, free disk space...), downloading RSS feeds, Winamp integration and support for several other popular applications. To support less common applications LCD Smartie uses a powerful plugin system.
The project was started as freeware by BasieP who wrote it in Delphi. After running the software as freeware from 2001 to late 2004, BasieP passed the project on to Chris Lansley as an Open Source project hosted on the SourceForge servers. Chris Lansley maintained the project for few years, and now the whole project remains alive thanks to the program community.
LCD Smartie is a relatively mature software and development of the main executable has slowed considerably, most of the new features are introduced by new plugins which are released by both the core team and by the community. The LCD Smartie forums are the primary source for support and developer discussion.
To facilitate the use of LCD Smartie on modern PCs running version of windows 7 and 8 the team has started working on a USB interface to connect LCDs to a PC that does not require any additional kernel driver and provides a complete plug and play experience.
External links
Official project page on SourceForge.
Official program forum
Limbo's home page with plugins for LCD Smartie.
lcdsmartie-laz An actively maintained fork
Free software
Liquid crystal displays
Pascal (programming language) software
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https://en.wikipedia.org/wiki/Subtalar%20joint
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In human anatomy, the subtalar joint, also known as the
talocalcaneal joint, is a joint of the foot. It occurs at the meeting point of the talus and the calcaneus.
The joint is classed structurally as a synovial joint, and functionally as a plane joint.
Structure
The talus is oriented slightly obliquely on the anterior surface of the calcaneus.
There are three points of articulation between the two bones: two anteriorly and one posteriorly. The three articulations are known as facets, and they are the posterior, middle and anterior facets.
At the anterior and middle talocalcaneal articulation, convex areas of the talus fits on to concave surfaces of the calcaneus.
The posterior talocalcaneal articulation is formed by a concave surface of the talus and a convex surface of the calcaneus.
The sustentaculum tali forms the floor of middle facet, and the anterior facet articulates with the head of the talus, and sits lateral and congruent to the middle facet. In some people the middle and anterior facets are joined giving just one articulation. The posterior facet is the largest of the three, and separated from the others by the tarsal canal.
Ligaments and membranes
The main ligament of the joint is the interosseous talocalcaneal ligament, a thick, strong band of two partially joined fibers that bind the talus and calcaneus. It runs through the sinus tarsi, a canal between the articulations of the two bones.
There are four additional ligaments that form weaker connections
between the talus and calcaneus.
The anterior talocalcaneal ligament (or anterior interosseous ligament) attaches at the neck of the talus on the front and lateral surfaces to the superior calcaneus.
The short band of the posterior talocalcaneal ligament extends from the lateral tubercle of the talus to the upper medial calcaneus.
The short, strong lateral talocalcaneal ligament connects from the lateral talus under the fibular facet to the lateral calcaneus, and runs parallel to the calca
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https://en.wikipedia.org/wiki/Medical%20transcription
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Medical transcription, also known as MT, is an allied health profession dealing with the process of transcribing voice-recorded medical reports that are dictated by physicians, nurses and other healthcare practitioners. Medical reports can be voice files, notes taken during a lecture, or other spoken material. These are dictated over the phone or uploaded digitally via the Internet or through smart phone apps.
History
Medical transcription as it is currently known has existed since the beginning of the 20th century when standardization of medical records and data became critical to research. At that time, medical stenographers recorded medical information, taking doctors' dictation in shorthand. With the creation of audio recording devices, it became possible for physicians and their transcribers to work asynchronously.
Over the years, transcription equipment has changed from manual typewriters, to electric typewriters, to word processors, and finally, , to computers. Storage methods have also changed: from plastic disks and magnetic belts to cassettes, endless loops, and digital recordings. Today, speech recognition (SR), also known as continuous speech recognition (CSR), is increasingly used, with medical transcriptions and, in some cases, "editors" providing supplemental editorial services. Natural-language processing takes "automatic" transcription a step further, providing an interpretive function that speech recognition alone does not provide.
In the past, these medical reports consisted of very abbreviated handwritten notes that were added in the patient's file for interpretation by the primary physician responsible for the treatment. Ultimately, these handwritten notes and typed reports were consolidated into a single patient file and physically stored along with thousands of other patient records in the medical records department. Whenever the need arose to review the records of a specific patient, the patient's file would be retrieved from the filing c
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https://en.wikipedia.org/wiki/Converse%20relation
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In mathematics, the converse relation, or transpose, of a binary relation is the relation that occurs when the order of the elements is switched in the relation. For example, the converse of the relation 'child of' is the relation 'parent of'. In formal terms, if and are sets and is a relation from to then is the relation defined so that if and only if In set-builder notation,
The notation is analogous with that for an inverse function. Although many functions do not have an inverse, every relation does have a unique converse. The unary operation that maps a relation to the converse relation is an involution, so it induces the structure of a semigroup with involution on the binary relations on a set, or, more generally, induces a dagger category on the category of relations as detailed below. As a unary operation, taking the converse (sometimes called conversion or transposition) commutes with the order-related operations of the calculus of relations, that is it commutes with union, intersection, and complement.
Since a relation may be represented by a logical matrix, and the logical matrix of the converse relation is the transpose of the original, the converse relation is also called the transpose relation. It has also been called the opposite or dual of the original relation, or the inverse of the original relation, or the reciprocal of the relation
Other notations for the converse relation include or
Examples
For the usual (maybe strict or partial) order relations, the converse is the naively expected "opposite" order, for examples,
A relation may be represented by a logical matrix such as
Then the converse relation is represented by its transpose matrix:
The converse of kinship relations are named: " is a child of " has converse " is a parent of ". " is a nephew or niece of " has converse " is an uncle or aunt of ". The relation " is a sibling of " is its own converse, since it is a symmetric relation.
Properties
In the monoid of binary end
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https://en.wikipedia.org/wiki/Delay%20differential%20equation
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In mathematics, delay differential equations (DDEs) are a type of differential equation in which the derivative of the unknown function at a certain time is given in terms of the values of the function at previous times.
DDEs are also called time-delay systems, systems with aftereffect or dead-time, hereditary systems, equations with deviating argument, or differential-difference equations. They belong to the class of systems with the functional state, i.e. partial differential equations (PDEs) which are infinite dimensional, as opposed to ordinary differential equations (ODEs) having a finite dimensional state vector. Four points may give a possible explanation of the popularity of DDEs:
Aftereffect is an applied problem: it is well known that, together with the increasing expectations of dynamic performances, engineers need their models to behave more like the real process. Many processes include aftereffect phenomena in their inner dynamics. In addition, actuators, sensors, and communication networks that are now involved in feedback control loops introduce such delays. Finally, besides actual delays, time lags are frequently used to simplify very high order models. Then, the interest for DDEs keeps on growing in all scientific areas and, especially, in control engineering.
Delay systems are still resistant to many classical controllers: one could think that the simplest approach would consist in replacing them by some finite-dimensional approximations. Unfortunately, ignoring effects which are adequately represented by DDEs is not a general alternative: in the best situation (constant and known delays), it leads to the same degree of complexity in the control design. In worst cases (time-varying delays, for instance), it is potentially disastrous in terms of stability and oscillations.
Voluntary introduction of delays can benefit the control system.
In spite of their complexity, DDEs often appear as simple infinite-dimensional models in the very complex ar
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https://en.wikipedia.org/wiki/Wengo
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Wengo was at the beginning of 2004 a subsidiary of French telecom service provider Neuf Cegetel. As of February 2012, Wengo employs 80 people in the Paris headquarters, and is a subsidiary of Vivendi. Wengo is now repositioned as an online personal and consulting services marketplace.
Voice over IP
Wengo was founded in September 2004, launching its service at the beginning of 2005 based on what is now known as the "WengoPhone, classic edition". In September 2005, Wengo opened its visiophony service at the same time as Skype on a cross platform (Windows, Linux and Mac OS X). In 2006, Wengo integrated the Gaim project into its software, allowing its users to communicate via Instant Messaging with other users on the MSN, Yahoo! or Google Talk networks.
Wengo and Skype started offering free PSTN calls in 2006, which accelerated the commoditization of telephony calls. In June 2006, Wengo offered a two-month unlimited calling plan to several destinations including Belgium, Guadeloupe, India, Martinique, Poland and Vietnam. The offer was posted on many websites, including FatWallet, and attracted many new customers. Wengo later suspended many of these accounts, in the company's interests, after many people began abusing the unlimited calling system.
WengoPhone
Originally, Wengo was supporting the development of WengoPhone. WengoPhone was a free and open source (GPL) VoIP (including video conferencing, SMS and chat) softphone through which it offered PC to PSTN phone calls. This software used the free and open SIP protocol, it was developed under the name WengoPhone by the OpenWengo project. Their Firefox browser extension was the first browser-based VoIP client for OS X. The VoIP service was presented on the French market as an attempt to compete with Skype, Yahoo and other virtual network service providers. The economic model of this activity, however, was not sustainable. Wengo decided that WengoPhone was outside its core business, and in February 2008 transferred t
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https://en.wikipedia.org/wiki/Nikolay%20Burdenko
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Nikolay Nilovich Burdenko (; – 11 November 1946) was a Russian Empire and Soviet surgeon, the founder of Russian neurosurgery. He was Surgeon-General of the Red Army (1937–1946), an academician of the USSR Academy of Sciences (from 1939), an academician and the first director of the Academy of Medical Sciences of the USSR (1944–1946), a Hero of Socialist Labor (from 1943), Colonel General of medical services, and a Stalin Prize winner (1941). He was a veteran of the Russo-Japanese War, First World War, Winter War and the German-Soviet War.
Early years
Nikolay Burdenko was born on 3 June 1876 in the village of Kamenka in the Nizhnelomovsky Uyezd of the Penza Governorate (modern-day Kamenka, Kamensky District, Penza Oblast of Russia), one of the eight children of Nil Karpovich Burdenko (1839—1906) and Varvara Markianovna Burdenko (née Smagina) (1851—1897). His paternal grandfather Karp Fyodorovich Burdenko came from serfs of the Kuznetsky Uezd of the Saratov Governorate where he served as a landlord's estate manager and his wife — as a maid; after being granted freedom they moved to Penza and then — to Verhniy Lomov of the Penza Governorate. Nikolay's father also worked as an estate manager for the major general Vladimir Voeykov (ru) who served in the Svita of Nicholas II and was close to the Emperor's family. Nikolay's mother was a housewife who came from peasants of the Tambov Governorate.
In 1885, Burdenko finished Kamenka zemstvo school and in 1886 entered Penza theological school to study for an Orthodox priest. In 1891, he entered Penza theological seminary and was soon sent to the Saint Petersburg Theological Academy as the best student. In 1897, he left it to study medicine at the recently opened Faculty of Medicine of the Tomsk Imperial University. There, he became fascinated with anatomy and operative surgery, and by the third course he was appointed as a prosector's assistant. He was then excluded from the university for participating in the 1899 Russian
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https://en.wikipedia.org/wiki/Method%20of%20averaging
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In mathematics, more specifically in dynamical systems, the method of averaging (also called averaging theory) exploits systems containing time-scales separation: a fast oscillation versus a slow drift. It suggests that we perform an averaging over a given amount of time in order to iron out the fast oscillations and observe the qualitative behavior from the resulting dynamics. The approximated solution holds under finite time inversely proportional to the parameter denoting the slow time scale. It turns out to be a customary problem where there exists the trade off between how good is the approximated solution balanced by how much time it holds to be close to the original solution.
More precisely, the system has the following form
of a phase space variable The fast oscillation is given by versus a slow drift of . The averaging method yields an autonomous dynamical system
which approximates the solution curves of inside a connected and compact region of the phase space and over time of .
Under the validity of this averaging technique, the asymptotic behavior of the original system is captured by the dynamical equation for . In this way, qualitative methods for autonomous dynamical systems may be employed to analyze the equilibria and more complex structures, such as slow manifold and invariant manifolds, as well as their stability in the phase space of the averaged system.
In addition, in a physical application it might be reasonable or natural to replace a mathematical model, which is given in the form of the differential equation for , with the corresponding averaged system , in order to use the averaged system to make a prediction and then test the prediction against the results of a physical experiment.
The averaging method has a long history, which is deeply rooted in perturbation problems that arose in celestial mechanics (see, for example in ).
First example
Consider a perturbed logistic growth
and the averaged equation
The purpose of the method o
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https://en.wikipedia.org/wiki/Security%20testing
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Security testing is a process intended to detect flaws in the security mechanisms of an information system and as such help enable it to protect data and maintain functionality as intended. Due to the logical limitations of security testing, passing the security testing process is not an indication that no flaws exist or that the system adequately satisfies the security requirements.
Typical security requirements may include specific elements of confidentiality, integrity, authentication, availability, authorization and non-repudiation. Actual security requirements tested depend on the security requirements implemented by the system. Security testing as a term has a number of different meanings and can be completed in a number of different ways. As such, a Security Taxonomy helps us to understand these different approaches and meanings by providing a base level to work from.
Confidentiality
A security measure which protects against the disclosure of information to parties other than the intended recipient is by no means the only way of ensuring the security.
Integrity
Integrity of information refers to protecting information from being modified by unauthorized parties
A measure intended to allow the receiver to determine that the information provided by a system is correct.
Integrity schemes often use some of the same underlying technologies as confidentiality schemes, but they usually involve adding information to a communication, to form the basis of an algorithmic check, rather than the encoding all of the communication.
To check if the correct information is transferred from one application to other.
Authentication
This might involve confirming the identity of a person, tracing the origins of an artifact, ensuring that a product is what its packaging and labelling claims to be, or assuring that a computer program is a trusted one.
Authorization
The process of determining that a requester is allowed to receive a service or perform an operation.
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https://en.wikipedia.org/wiki/Topology%20table
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A topology table is used by routers that route traffic in a network. It consists of all routing tables inside the Autonomous System where the router is positioned. Each router using the routing protocol EIGRP then maintains a topology table for each configured network protocol — all routes learned, that are leading to a destination are found in the topology table. EIGRP must have a reliable connection. The routing table of all routers of an Autonomous System is same.
Routing
Table
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https://en.wikipedia.org/wiki/Rake%20%28software%29
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Rake is a software task management and build automation tool created by Jim Weirich. It allows the user to specify tasks and describe dependencies as well as to group tasks in a namespace. It is similar to SCons and Make. It's written in the Ruby programming language and the Rakefiles (equivalent of Makefiles in Make) use Ruby syntax. Rake uses Ruby's anonymous function blocks to define various tasks, allowing the use of Ruby syntax. It has a library of common tasks: for example, functions to do common file-manipulation tasks and a library to remove compiled files (the "clean" task). Like Make, Rake can also synthesize tasks based on patterns: for example, automatically building a file compilation task based on filename patterns. Rake is now part of the standard library of Ruby from version 1.9 onward.
Example
Below is an example of a simple Rake script to build a C Hello World program.
file 'hello.o' => 'hello.c' do
sh 'cc -c -o hello.o hello.c'
end
file 'hello' => 'hello.o' do
sh 'cc -o hello hello.o'
end
Rules
When a file is named as a prerequisite but it does not have a file task defined for it, Rake will attempt to synthesize a task by looking at a list of rules supplied in the Rakefile. For example, suppose we were trying to invoke task "mycode.o" with no tasks defined for it. If the Rakefile has a rule that looks like this:
rule '.o' => '.c' do |t|
sh "cc #{t.source} -c -o #{t.name}"
end
This rule will synthesize any task that ends in ".o". It has as a prerequisite that a source file with an extension of ".c" must exist. If Rake is able to find a file named "mycode.c", it will automatically create a task that builds "mycode.o" from "mycode.c". If the file "mycode.c" does not exist, Rake will attempt to recursively synthesize a rule for it.
When a task is synthesized from a rule, the source attribute of the task is set to the matching source file. This allows users to write rules with actions that reference the source file.
Advanced rules
Any reg
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