source stringlengths 31 227 | text stringlengths 9 2k |
|---|---|
https://en.wikipedia.org/wiki/Monopolin | Monopolin is a protein complex that in budding yeast is composed of the four proteins CSM1, HRR25, LRS4, and MAM1. Monopolin is required for the segregation of homologous centromeres to opposite poles of a dividing cell during anaphase I of meiosis. This occurs by bridging DSN1 kinetochore proteins to sister kinetochores within the centromere to physically fuse them and allow for the microtubules to pull each homolog toward opposite mitotic spindles.
Molecular structure
Monopolin is composed of a 4 CSM1:2 LRS4 complex which forms a V-shaped structure with two globular heads at the ends, which are responsible for directly crosslinking sister kinetochores. Bound to each CSM1 head is a MAM1 protein which recruits one copy of the HRR25 kinase. The hydrophobic cavity on the CSM1 subunit allows the hydrophobic regions of Monopolin receptor and kinetochore protein, DSN1, to bind to and fuse the sister kinetochores. Microtubules can then attach to the kinetochores on the homologous centromeres and pull them toward opposite mitotic spindles to complete anaphase of meiosis I. |
https://en.wikipedia.org/wiki/Separatrix%20%28mathematics%29 | In mathematics, a separatrix is the boundary separating two modes of behaviour in a differential equation.
Example: simple pendulum
Consider the differential equation describing the motion of a simple pendulum:
where denotes the length of the pendulum, the gravitational acceleration and the angle between the pendulum and vertically downwards. In this system there is a conserved quantity H (the Hamiltonian), which is given by
With this defined, one can plot a curve of constant H in the phase space of system. The phase space is a graph with along the horizontal axis and on the vertical axis – see the thumbnail to the right. The type of resulting curve depends upon the value of H.
If then no curve exists (because must be imaginary).
If then the curve will be a simple closed curve which is nearly circular for small H and becomes "eye" shaped when H approaches the upper bound. These curves correspond to the pendulum swinging periodically from side to side.
If then the curve is open, and this corresponds to the pendulum forever swinging through complete circles.
In this system the separatrix is the curve that corresponds to . It separates — hence the name — the phase space into two distinct areas, each with a distinct type of motion. The region inside the separatrix has all those phase space curves which correspond to the pendulum oscillating back and forth, whereas the region outside the separatrix has all the phase space curves which correspond to the pendulum continuously turning through vertical planar circles.
Example: FitzHugh–Nagumo model
In the FitzHugh–Nagumo model, when the linear nullcline pierces the cubic nullcline at the left, middle, and right branch once each, the system has a separatrix. Trajectories to the left of the separatrix converge to the left stable equilibrium, and similarly for the right. The separatrix itself is the stable manifold for the saddle point in the middle. Details are found in the page.
The separatrix is cle |
https://en.wikipedia.org/wiki/Dihedral%20symmetry%20in%20three%20dimensions | In geometry, dihedral symmetry in three dimensions is one of three infinite sequences of point groups in three dimensions which have a symmetry group that as an abstract group is a dihedral group Dihn (for n ≥ 2).
Types
There are 3 types of dihedral symmetry in three dimensions, each shown below in 3 notations: Schönflies notation, Coxeter notation, and orbifold notation.
Chiral
Dn, [n,2]+, (22n) of order 2n – dihedral symmetry or para-n-gonal group (abstract group: Dihn).
Achiral
Dnh, [n,2], (*22n) of order 4n – prismatic symmetry or full ortho-n-gonal group (abstract group: Dihn × Z2).
Dnd (or Dnv), [2n,2+], (2*n) of order 4n – antiprismatic symmetry or full gyro-n-gonal group (abstract group: Dih2n).
For a given n, all three have n-fold rotational symmetry about one axis (rotation by an angle of 360°/n does not change the object), and 2-fold rotational symmetry about a perpendicular axis, hence about n of those. For n = ∞, they correspond to three Frieze groups. Schönflies notation is used, with Coxeter notation in brackets, and orbifold notation in parentheses. The term horizontal (h) is used with respect to a vertical axis of rotation.
In 2D, the symmetry group Dn includes reflections in lines. When the 2D plane is embedded horizontally in a 3D space, such a reflection can either be viewed as the restriction to that plane of a reflection through a vertical plane, or as the restriction to the plane of a rotation about the reflection line, by 180°. In 3D, the two operations are distinguished: the group Dn contains rotations only, not reflections. The other group is pyramidal symmetry Cnv of the same order, 2n.
With reflection symmetry in a plane perpendicular to the n-fold rotation axis, we have Dnh, [n], (*22n).
Dnd (or Dnv), [2n,2+], (2*n) has vertical mirror planes between the horizontal rotation axes, not through them. As a result, the vertical axis is a 2n-fold rotoreflection axis.
Dnh is the symmetry group for a regular n-sided prism and also for a |
https://en.wikipedia.org/wiki/Chlorobium | Chlorobium is a genus of green sulfur bacteria. They are photolithotrophic oxidizers of sulfur and most notably utilise a noncyclic electron transport chain to reduce NAD+. Photosynthesis is achieved using a Type 1 Reaction Centre using bacteriochlorophyll (BChl) a. Two photosynthetic antenna complexes aid in light absorption: the Fenna-Matthews-Olson complex ("FMO", also containing BChl a), and the chlorosomes which employ mostly BChl c, d, or e. Hydrogen sulfide is used as an electron source and carbon dioxide its carbon source.
Chlorobium species exhibit a dark green color; in a Winogradsky column, the green layer often observed is composed of Chlorobium. This genus lives in strictly anaerobic conditions below the surface of a body of water, commonly the anaerobic zone of a eutrophic lake.
Chlorobium aggregatum is a species which exists in a symbiotic relationship with a colorless, nonphotosynthetic bacteria. This species looks like a bundle of green bacteria, attached to a central rod-like cell which can move around with a flagellum. The green, outer bacteria use light to oxidize sulfide into sulfate. The inner cell, which is not able to perform photosynthesis, reduces the sulfate into sulfide. These bacteria divide in unison, giving the structure a multicellular appearance which is highly unusual in bacteria.
Chlorobium species are thought to have played an important part in mass extinction events on Earth. If the oceans turn anoxic (due to the shutdown of ocean circulation) then Chlorobium would be able to out compete other photosynthetic life. They would produce huge quantities of methane and hydrogen sulfide which would cause global warming and acid rain. This would have huge consequences for other oceanic organisms and also for terrestrial organisms. Evidence for abundant Chlorobium populations is provided by chemical fossils found in sediments deposited at the Cretaceous mass extinction.
Molecular signatures for Chlorobiota
Comparative genomic analysi |
https://en.wikipedia.org/wiki/The%20Lady%20Tasting%20Tea | The Lady Tasting Tea: How Statistics Revolutionized Science in the Twentieth Century () is a book by David Salsburg about the history of modern statistics and the role it played in the development of science and industry.
The title comes from the "lady tasting tea", an example from the famous book, The Design of Experiments, by Ronald A. Fisher. Regarding Fisher's example, the statistician Debabrata Basu wrote that "the famous case of the 'lady tasting tea'" was "one of the two supporting pillars [...] of the randomization analysis of experimental data".
Summary
The book discusses the statistical revolution which took place in the twentieth century, where science shifted from a deterministic view (Clockwork universe) to a perspective concerned primarily with probabilities and distributions and parameters. Salsburg does this through a collection of stories about the people who were fundamental in the change, starting with men like R.A. Fisher and Karl Pearson. He discusses at length how many of these people had their own philosophy of statistics, and in particular their own understanding of statistical significance. Throughout, he introduces in a very nontechnical fashion a variety of statistical ideas and methods, such as maximum likelihood estimation and bootstrapping.
Reception
The book was generally well-received, receiving coverage in a variety of medical and statistical journals. Reviewers from the medical field enjoyed Salsburg's coverage of Fisher's opposition to early research on the health effects of tobacco. Critics disagreed with certain opinions that Salsburg voiced, like his barebones portrayal of Bayesian statistics and his seeming disdain for pure mathematics. Nevertheless, almost all reviewers appreciated the interesting read and recommended the book to people in their field as well as a general audience.
List of scholars mentioned
The book discusses a wide variety of statisticians, mathematicians, as well as other scientists and scholars. |
https://en.wikipedia.org/wiki/RF%20antenna%20ion%20source | An RF antenna ion source (or radio frequency antenna ion source) is an internal multi-cusp design that can produce a particle beam of about ~30 to 40 mA current. It is used in high energy particle physics and in accelerator laboratories.
Previous RF antennas would penetrate the porcelain enamel coating on the antenna section at high RF power. This problem has been corrected in the development stage with a ten layer coating of titanium dioxide, with approximately 1 mm thick coating.
With the development of the RF antenna ion source, or "non-thermionic ion source," the ion source has an advantage over conventional cold cathodes and hot filament ion sources. The filament continuously burns out over time with a shorter lifespan, requiring venting of the ion source to atmosphere and rebuilding of the ion source.
See also
Ion source
Particle accelerator
External links
Lawrence Berkley National Laboratory Improvement of the lifetime of radio frequency antenna
Particle physics
Accelerator physics |
https://en.wikipedia.org/wiki/Tombstone%20%28programming%29 | Tombstones are a mechanism to detect dangling pointers and mitigate the problems they can cause in computer programs. Dangling pointers can appear in certain computer programming languages, e.g. C, C++ and assembly languages.
A tombstone is a structure that acts as an intermediary between a pointer and its target, often heap-dynamic data in memory. The pointer – sometimes called the handle – points only at tombstones and never to its actual target. When the data is deallocated, the tombstone is set to a null (or, more generally, to a value that is illegal for a pointer in the given runtime environment), indicating that the variable no longer exists. This mechanism prevents the use of invalid pointers, which would otherwise access the memory area that once belonged to the now deallocated variable, although it may already contain other data, in turn leading to corruption of in-memory data. Depending on the operating system, the CPU can automatically detect such an invalid access (e.g. for the null value: a null pointer dereference error). This supports in analyzing the actual reason, a programming error, in debugging, and it can also be used to abort the program in production use, to prevent it from continuing with invalid data structures.
In more generalized terms, a tombstone can be understood as a marker for "this data is no longer here". For example, in filesystems it may be efficient when deleting files to mark them as "dead" instead of immediately reclaiming all their data blocks.
The downsides of using tombstones include a computational overhead and additional memory consumption: extra processing is necessary to follow the path from the pointer to data through the tombstone, and extra memory is necessary to retain tombstones for every pointer throughout the program. One other problem is that all the code that needs to work with the pointers in question needs to be implemented to use the tombstone mechanism.
Among popular programming languages, C++ implemen |
https://en.wikipedia.org/wiki/Psorosperm | Psorosperm (from the Greek ψωρα itch and σπερμα seed) is a former name of a number of parasitic protozoa that produce cystlike or sporelike structures in the tissue of hosts. The term is now essentially obsolete.
Some that affect vertebrate hosts are now called coccidia.
Others, such as the cause of pébrine in silkworms, are now recognized as microsporidians, and some are myxosporidians.
The genus Psorospermium (which includes the species Psorospermium haeckeli) itself is a parasite of crayfishes, and belongs to an enigmatic group of unicellular organisms that some biologists think may be related to the common ancestors of animals and fungi.
J. Müller introduced the term in German (as Psorospermien) in 1841.
Psorosperm was at one point believed to be the cause of Darier's disease.
"Psorospermiasis" is classified under 136.4 in ICD-9. |
https://en.wikipedia.org/wiki/Interprime | In mathematics, an interprime is the average of two consecutive odd primes. For example, 9 is an interprime because it is the average of 7 and 11. The first interprimes are:
4, 6, 9, 12, 15, 18, 21, 26, 30, 34, 39, 42, 45, 50, 56, 60, 64, 69, 72, 76, 81, 86, 93, 99, ...
Interprimes cannot be prime themselves (otherwise the primes would not have been consecutive).
There are infinitely many primes and therefore also infinitely many interprimes. The largest known interprime may be the 388342-digit n = 2996863034895 · 21290000, where n + 1 is the largest known twin prime.
See also
Prime gap
Twin primes
Cousin prime
Sexy prime
Balanced prime – a prime number with equal-sized prime gaps above and below it |
https://en.wikipedia.org/wiki/Inductive%20effect | In chemistry, the inductive effect in a molecule is a local change in the electron density due to electron-withdrawing or electron-donating groups elsewhere in the molecule, resulting in a permanent dipole in a bond.
It is present in a σ (sigma) bond, unlike the electromeric effect which is present in a π (pi) bond.
The halogen atoms in an alkyl halide are electron withdrawing while the alkyl groups have electron donating tendencies. If the electronegative atom (missing an electron, thus having a positive charge) is then joined to a chain of atoms, usually carbon, the positive charge is relayed to the other atoms in the chain. This is the electron-withdrawing inductive effect, also known as the -I effect. In short, alkyl groups tend to donate electrons, leading to the +I effect. Its experimental basis is the ionization constant. It is distinct from and often opposite to the mesomeric effect.
Bond polarization
Covalent bonds can be polarized depending on the relative electronegativity of the two atoms forming the bond. The electron cloud in a σ-bond between two unlike atoms is not uniform and is slightly displaced towards the more electronegative of the two atoms. This causes a permanent state of bond polarization, where the more electronegative atoms has a fractional negative charge (δ–) and the less electronegative atom has a fractional positive charge (δ+).
For example, the water molecule has an electronegative oxygen atom that attracts a negative charge. This is indicated by δ- in the water molecule in the vicinity of the O atom, as well as by a δ+ next to each of the two H atoms. The vector addition of the individual bond dipole moments results in a net dipole moment for the molecule. A polar bond is a covalent bond in which there is a separation of charge between one end and the other - in other words in which one end is slightly positive and the other slightly negative. Examples include most covalent bonds. The hydrogen-chlorine bond in HCl or the hydroge |
https://en.wikipedia.org/wiki/Ioctl | In computing, ioctl (an abbreviation of input/output control) is a system call for device-specific input/output operations and other operations which cannot be expressed by regular system calls. It takes a parameter specifying a request code; the effect of a call depends completely on the request code. Request codes are often device-specific. For instance, a CD-ROM device driver which can instruct a physical device to eject a disc would provide an ioctl request code to do so. Device-independent request codes are sometimes used to give userspace access to kernel functions which are only used by core system software or still under development.
The ioctl system call first appeared in Version 7 of Unix under that name. It is supported by most Unix and Unix-like systems, including Linux and macOS, though the available request codes differ from system to system. Microsoft Windows provides a similar function, named "DeviceIoControl", in its Win32 API.
Background
Conventional operating systems can be divided into two layers, userspace and the kernel. Application code such as a text editor resides in userspace, while the underlying facilities of the operating system, such as the network stack, reside in the kernel. Kernel code handles sensitive resources and implements the security and reliability barriers between applications; for this reason, user mode applications are prevented by the operating system from directly accessing kernel resources.
Userspace applications typically make requests to the kernel by means of system calls, whose code lies in the kernel layer. A system call usually takes the form of a "system call vector", in which the desired system call is indicated with an index number. For instance, exit() might be system call number 1, and write() number 4. The system call vector is then used to find the desired kernel function for the request. In this way, conventional operating systems typically provide several hundred system calls to the userspace.
Thoug |
https://en.wikipedia.org/wiki/Layered%20Service%20Provider | Layered Service Provider (LSP) is a deprecated feature of the Microsoft Windows Winsock 2 Service Provider Interface (SPI). A Layered Service Provider is a DLL that uses Winsock APIs to attempt to insert itself into the TCP/IP protocol stack. Once in the stack, a Layered Service Provider can intercept and modify inbound and outbound Internet traffic. It allows processing of all the TCP/IP traffic taking place between the Internet and the applications that are accessing the Internet (such as a web browser, the email client, etc.). For example, it could be used by malware to redirect web browers to rogue websites, or to block access to sites like Windows Update. Alternatively, a computer security program could scan network traffic for viruses or other threats. The Winsock Service Provider Interface (SPI) API provides a mechanism for layering providers on top of each other. Winsock LSPs are available for a range of useful purposes, including parental controls and Web content filtering. The parental controls web filter in Windows Vista is an LSP. The layering order of all providers is kept in the Winsock Catalog.
Details
Unlike the well-known Winsock 2 API, which is covered by numerous books, documentation, and samples, the Winsock 2 SPI is relatively unexplored. The Winsock 2 SPI is implemented by network transport service providers and namespace resolution service providers. The Winsock 2 SPI can be used to extend an existing transport service provider by implementing a Layered Service Provider. For example, quality of service (QoS) on Windows 98 and Windows 2000 is implemented as an LSP over the TCP/IP protocol stack. Another use for LSPs would be to develop specialized URL filtering software to prevent Web browsers from accessing certain sites, regardless of the browser installed on a desktop.
The Winsock 2 SPI allows software developers to create two different types of service providers—transport and namespace. Transport providers (commonly referred to as proto |
https://en.wikipedia.org/wiki/Electromagnetic%20wave%20equation | The electromagnetic wave equation is a second-order partial differential equation that describes the propagation of electromagnetic waves through a medium or in a vacuum. It is a three-dimensional form of the wave equation. The homogeneous form of the equation, written in terms of either the electric field or the magnetic field , takes the form:
where
is the speed of light (i.e. phase velocity) in a medium with permeability , and permittivity , and is the Laplace operator. In a vacuum, , a fundamental physical constant. The electromagnetic wave equation derives from Maxwell's equations. In most older literature, is called the magnetic flux density or magnetic induction. The following equationspredicate that any electromagnetic wave must be a transverse wave, where the electric field and the magnetic field are both perpendicular to the direction of wave propagation.
The origin of the electromagnetic wave equation
In his 1865 paper titled A Dynamical Theory of the Electromagnetic Field, James Clerk Maxwell utilized the correction to Ampère's circuital law that he had made in part III of his 1861 paper On Physical Lines of Force. In Part VI of his 1864 paper titled Electromagnetic Theory of Light, Maxwell combined displacement current with some of the other equations of electromagnetism and he obtained a wave equation with a speed equal to the speed of light. He commented:
The agreement of the results seems to show that light and magnetism are affections of the same substance, and that light is an electromagnetic disturbance propagated through the field according to electromagnetic laws.
Maxwell's derivation of the electromagnetic wave equation has been replaced in modern physics education by a much less cumbersome method involving combining the corrected version of Ampère's circuital law with Faraday's law of induction.
To obtain the electromagnetic wave equation in a vacuum using the modern method, we begin with the modern 'Heaviside' form of Maxwell's |
https://en.wikipedia.org/wiki/Return%20of%20capital | Return of capital (ROC) refers to principal payments back to "capital owners" (shareholders, partners, unitholders) that exceed the growth (net income/taxable income) of a business or investment. It should not be confused with Rate of Return (ROR), which measures a gain or loss on an investment. It is essentially a return of some or all of the initial investment, which reduces the basis on that investment.
ROC effectively shrinks the firm's equity in the same way that all distributions do. It is a transfer of value from the company to the owner. In an efficient market, the stock's price will fall by an amount equal to the distribution. Most public companies pay out only a percentage of their income as dividends. In some industries it is common to pay ROC.
Real Estate Investment Trusts (REITs) commonly make distributions equal to the sum of their income and the depreciation (capital cost allowance) allowed for in the calculation of that income. The business has the cash to make the distribution because depreciation is a non-cash charge.
Oil and gas royalty trusts also make distributions that include ROC equal to the drawdown in the quantity of their reserves. Again, the cash to find the O&G was spent previously, and current operations are generating excess cash.
Private businesses can distribute any amount of equity that the owners need personally.
Structured Products (closed ended investment funds) frequently use high distributions, that include returns of capital, as a promotional tool. The retail investors these funds are sold to rarely have the technical knowledge to distinguish income from ROC.
Public business may return capital as a means to increase the debt/equity ratio and increase their leverage (risk profile). When the value of real estate holdings (for example) have increased, the owners may realize some of the increased value immediately by taking a ROC and increasing debt. This may be considered analogous to cash out refinancing of a residential |
https://en.wikipedia.org/wiki/Odious%20number | In number theory, an odious number is a positive integer that has an odd number of 1s in its binary expansion. Non-negative integers that are not odious are called evil numbers.
In computer science, an odious number is said to have odd parity.
Examples
The first odious numbers are:
Properties
If denotes the th odious number (with ), then for all , .
Every positive integer has an odious multiple that is at most . The numbers for which this bound is tight are exactly the Mersenne numbers with even exponents, the numbers of the form , such as 3, 15, 63, etc. For these numbers, the smallest odious multiple is exactly .
Related sequences
The odious numbers give the positions of the nonzero values in the Thue–Morse sequence. Every power of two is odious, because its binary expansion has only one nonzero bit. Except for 3, every Mersenne prime is odious, because its binary expansion consists of an odd prime number of consecutive nonzero bits.
Non-negative integers that are not odious are called evil numbers. The partition of the non-negative integers into the odious and evil numbers is the unique partition of these numbers into two sets that have equal multisets of pairwise sums. |
https://en.wikipedia.org/wiki/SOLEIL | SOLEIL ("Sun" in French) is a synchrotron facility near Paris, France. It performed its first acceleration of electrons on May 14, 2006. The name SOLEIL is a backronym for Source optimisée de lumière d’énergie intermédiaire du LURE (LURE optimised intermediary energy light source), LURE meaning Laboratoire pour l'utilisation du rayonnement électromagnétique.
The facility is run by a civil corporation held by the French National Centre for Scientific Research (CNRS) and the French Alternative Energies and Atomic Energy Commission (CEA), two French national research agencies. It is located in Saint-Aubin in the Essonne département, a south-western suburb of Paris, near Gif-sur-Yvette and Saclay, which host other facilities for nuclear and particle physics.
The facility is an associate member of the University of Paris-Saclay.
SOLEIL also hosts IPANEMA, the European research platform on ancient materials (archaeology, palaeontology, past environments and cultural heritage), a joint CNRS / French Ministry of Culture and Communication research unit.
SOLEIL covers fundamental research needs in physics, chemistry, material sciences, life sciences (notably in the crystallography of biological macromolecules), earth sciences, and atmospheric sciences. It offers the use of a wide range of spectroscopic methods from infrared to X-rays, and structural methods such as X-ray diffraction and scattering.
Main parameters
SOLEIL contains electrons travelling with an energy of 2.75 GeV around a 354 m circumference. It takes the electrons 1.2 μs to travel around this ring at almost the speed of light; 847,000 times per second.
Notable Experiments |
https://en.wikipedia.org/wiki/Hox%20gene | Hox genes, a subset of homeobox genes, are a group of related genes that specify regions of the body plan of an embryo along the head-tail axis of animals. Hox proteins encode and specify the characteristics of 'position', ensuring that the correct structures form in the correct places of the body. For example, Hox genes in insects specify which appendages form on a segment (for example, legs, antennae, and wings in fruit flies), and Hox genes in vertebrates specify the types and shape of vertebrae that will form. In segmented animals, Hox proteins thus confer segmental or positional identity, but do not form the actual segments themselves.
Studies on Hox genes in ciliated larvae have shown they are only expressed in future adult tissues. In larvae with gradual metamorphosis the Hox genes are activated in tissues of the larval body, generally in the trunk region, that will be maintained through metamorphosis. In larvae with complete metamorphosis the Hox genes are mainly expressed in juvenile rudiments and are absent in the transient larval tissues. The larvae of the hemichordate species Schizocardium californicum and the pilidium larva of Nemertea do not express Hox genes.
An analogy for the Hox genes can be made to the role of a play director who calls which scene the actors should carry out next. If the play director calls the scenes in the wrong order, the overall play will be presented in the wrong order. Similarly, mutations in the Hox genes can result in body parts and limbs in the wrong place along the body. Like a play director, the Hox genes do not act in the play or participate in limb formation themselves.
The protein product of each Hox gene is a transcription factor. Each Hox gene contains a well-conserved DNA sequence known as the homeobox, of which the term "Hox" was originally a contraction. However, in current usage the term Hox is no longer equivalent to homeobox, because Hox genes are not the only genes to possess a homeobox sequence; for inst |
https://en.wikipedia.org/wiki/Calculator%20spelling | Calculator spelling is an unintended characteristic of the seven-segment display traditionally used by calculators, in which, when read upside-down, the digits resemble letters of the Latin alphabet. Each digit may be mapped to one or more letters, creating a limited but functional subset of the alphabet, sometimes referred to as beghilos (or beghilosz).
Applications
Aside from novelty and amusement, calculator spelling has limited utility. The popularity of pagers in the 1990s gave rise to a form of leetspeak called pagerspeak. Students, in particular, experimented with calculators to discover new words.
English version
The "original" attributed example of calculator spelling, which dates from the 1970s, is 5318008, which when turned over spells "BOOBIES". Another early example of calculator spelling offered the sequence 0.7734, which becomes "hello", or could also be written as "0.1134". The 1979 album Five Three One - Double Seven O Four by The Hollies encodes the band's name in calculator spelling ("hOLLIES"). Other words possible with the traditional "BEghILOSZ" set include "loose", "shell", "BEIgE", "gOBBLE", "gOOgLE", and many others. Among the longest are "hILLBILLIES" and "SLEIghBELLS" at 11, "gLOSSOLOgIES" and "BIBLIOLOgIES" at 12 letters, and "hEEBEEgEEBEES" at 13 letters. Another common case, 7734206, spells "gO 2 hELL". 8008 is special in that it can spell "BOOB" upside-down or right-side up. 71077345 spells "SHELLOIL". There are also a couple of names that are able to be calculator spelled. For example, 7718=BILL, 46137=LEIgh, 5107=LOIS, 31773=ELLIE, 31717173=ELI LILIE (in Polish: lily flowers of Elisabeth) and 302=ZOE.
80085 (BOOBS) was used as a gag in the episode Mortyplicity of Rick and Morty. During the episode, Rick Sanchez disables clones of the Smith family with the phrase "Analysis mode; password 80085.". His daughter, Beth Smith, makes the comment "Kinda expected a funnier password."
Scientific and programmer calculators
Scientific |
https://en.wikipedia.org/wiki/Dropping%20out | Dropping out refers to leaving high school, college, university or another group for practical reasons, necessities, inability, apathy, or disillusionment with the system from which the individual in question leaves.
Canada
In Canada, most individuals graduate from grade 12 by the age of 18, according to Jason Gilmore who collects data on employment and education using the Labour Force Survey. The LFS is the official survey used to collect unemployment data in Canada (2010). Using this tool, assessing educational attainment and school attendance can calculate a dropout rate (Gilmore, 2010). It was found by the LFS that by 2009, one in twelve 20- to 24-year-old adults did not have a high school diploma (Gilmore, 2010). The study also found that men still have higher dropout rates than women, and that students outside of major cities and in the northern territories also have a higher risk of dropping out. Although since 1990 dropout rates have gone down from 20% to a low of 9% in 2010, the rate does not seem to be dropping since this time (2010).
The average Canadian dropout earns $70 less per week than their peers with a high school diploma. Graduates (without post-secondary) earned an average of $621 per week, whereas dropout students earned an average of $551 (Gilmore, 2010).
Even though dropout rates have gone down in the last 20 to 25 years, the concerns of the impact dropping out has on the labour market are very real (Gilmore, 2010). One in four students without a high school diploma who was in the labour market in 2009-2010 had less likelihood of finding a job due to economic downturn (Gilmore, 2010).
In 2018, graduation rates at universities within Canada were as low as 44% (Macleans, 2018). This is almost half of the student population (Macleans, 2018) There tends to be an increase in students dropping-out as a result of feeling disconnected from their school community (Binfet et al., 2016). This is most common with students within their first two year |
https://en.wikipedia.org/wiki/Metalorganic%20vapour-phase%20epitaxy | Metalorganic vapour-phase epitaxy (MOVPE), also known as organometallic vapour-phase epitaxy (OMVPE) or metalorganic chemical vapour deposition (MOCVD), is a chemical vapour deposition method used to produce single- or polycrystalline thin films. It is a process for growing crystalline layers to create complex semiconductor multilayer structures. In contrast to molecular-beam epitaxy (MBE), the growth of crystals is by chemical reaction and not physical deposition. This takes place not in vacuum, but from the gas phase at moderate pressures (10 to 760 Torr). As such, this technique is preferred for the formation of devices incorporating thermodynamically metastable alloys, and it has become a major process in the manufacture of optoelectronics, such as Light-emitting diodes. It was invented in 1968 at North American Aviation (later Rockwell International) Science Center by Harold M. Manasevit.
Basic principles
In MOCVD ultrapure precursor gases are injected into a reactor, usually with a non-reactive carrier gas. For a III-V semiconductor, a metalorganic could be used as the group III precursor and a hydride for the group V precursor. For example, indium phosphide can be grown with trimethylindium ((CH3)3In) and phosphine (PH3) precursors.
As the precursors approach the semiconductor wafer, they undergo pyrolysis and the subspecies absorb onto the semiconductor wafer surface. Surface reaction of the precursor subspecies results in the incorporation of elements into a new epitaxial layer of the semiconductor crystal lattice. In the mass-transport-limited growth regime in which MOCVD reactors typically operate, growth is driven by supersaturation of chemical species in the vapor phase. MOCVD can grow films containing combinations of group III and group V, group II and group VI, group IV.
Required pyrolysis temperature increases with increasing chemical bond strength of the precursor. The more carbon atoms are attached to the central metal atom, the weaker the |
https://en.wikipedia.org/wiki/Pulegone | Pulegone is a naturally occurring organic compound obtained from the essential oils of a variety of plants such as Nepeta cataria (catnip), Mentha piperita, and pennyroyal. It is classified as a monoterpene.
Pulegone is a clear colorless oily liquid and has a pleasant odor similar to pennyroyal, peppermint and camphor. It is used in flavoring agents, in perfumery, and in aromatherapy.
Toxicology
It was reported that the chemical is toxic to rats if a large quantity is consumed.
Pulegone is also an insecticide − the most powerful of three insecticides naturally occurring in many mint species.
As of October 2018, the FDA withdrew authorization for the use of pulegone as a synthetic flavoring substance for use in food, but that naturally-occurring pulegone can continue to be used.
Sources
Creeping charlie
Mentha longifolia
Mentha suaveolens
Pennyroyal
Peppermint
Schizonepeta tenuifolia
Bursera graveolens
See also
Menthofuran
Menthol |
https://en.wikipedia.org/wiki/Gentleman%27s%20Relish | Gentleman's Relish is a British commercial brand of anchovy paste. It is also known as Patum Peperium (meaning 'pepper paste' in Latin). Created in 1828 by an Englishman named John Osborn, it is a savoury paste with a salty and slightly fishy taste, and contains salted anchovies (minimum 60%), butter, herbs and spices. Today, the secret recipe is withheld from all but one employee at Elsenham Quality Foods in Elsenham, England, the licensed manufacturer.
Uses
Gentleman's Relish is traditionally eaten very thinly spread on slices of hot buttered white-bread toast, either on its own, or with cucumber or "mustard and cress" sprouts. It can also be added to minced meat for a different-tasting cottage pie or to the mixture for fish cakes, potato cakes and croquettes. Alternatively it can be melted into scrambled eggs or be used as a topping for jacket potatoes. It is an ingredient in the dish Scotch woodcock.
Variations
Elsenham Quality Foods also make a similarly packaged product, Poacher's Relish, which is made from smoked salmon, butter, spices and lemon zest. Both types of relish are sold in plastic containers (pictured), and in more expensive but reusable and decorative traditional ceramic pots. Since 2008 a third variation, Angler's Relish, made from smoked mackerel, salted butter, lemon juice, vinegar, spices and other ingredients was introduced in commemorative packaging to mark the 180th anniversary of John Osborn's original creation. Both are also usually eaten on toast or savoury biscuits, in common with the original recipe.
See also
Garum
List of brand name condiments
Relish |
https://en.wikipedia.org/wiki/Collaboration%20Data%20Objects | Collaboration Data Objects (CDO), previously known as OLE Messaging or Active Messaging, is an application programming interface included with Microsoft Windows and Microsoft Exchange Server products. The library allows developers to access the Global Address List and other server objects, in addition to the contents of mailboxes and public folders.
Overview
CDO is a technology for building messaging or collaboration applications. CDO can be used separately or in connection with Outlook Object Model to gain more access over Outlook. CDO is not a part of Outlook Object Model and it doesn't provide any event-based functionality, nor can Outlook objects be manipulated using CDO.
Starting with Exchange 2007, neither the Messaging API (MAPI) client libraries nor CDO 1.2.1 are provided as a part of the base product installation. They are available as downloads.
Versions
CDONTS: available on Windows NT 4.0 by installing the Option Pack, or Exchange Server.
CDOSYS: available on Windows 2000 and onwards by installing the SMTP service in Internet Information Server (IIS).
See also
Collaboration Data Objects for Windows NT Server
MAPI
ActiveX |
https://en.wikipedia.org/wiki/Cyclic%20symmetry%20in%20three%20dimensions | In three dimensional geometry, there are four infinite series of point groups in three dimensions (n≥1) with n-fold rotational or reflectional symmetry about one axis (by an angle of 360°/n) that does not change the object.
They are the finite symmetry groups on a cone. For n = ∞ they correspond to four frieze groups. Schönflies notation is used. The terms horizontal (h) and vertical (v) imply the existence and direction of reflections with respect to a vertical axis of symmetry. Also shown are Coxeter notation in brackets, and, in parentheses, orbifold notation.
Types
Chiral
Cn, [n]+, (nn) of order n - n-fold rotational symmetry - acro-n-gonal group (abstract group Zn); for n=1: no symmetry (trivial group)
AchiralCnh, [n+,2], (n*) of order 2n - prismatic symmetry or ortho-n-gonal group (abstract group Zn × Dih1); for n=1 this is denoted by Cs (1*) and called reflection symmetry, also bilateral symmetry. It has reflection symmetry with respect to a plane perpendicular to the n-fold rotation axis.Cnv, [n], (*nn) of order 2n - pyramidal symmetry or full acro-n-gonal group (abstract group Dihn); in biology C2v is called biradial symmetry. For n=1 we have again Cs (1*). It has vertical mirror planes. This is the symmetry group for a regular n-sided pyramid.S2n, [2+,2n+], (n×) of order 2n - gyro-n-gonal group (not to be confused with symmetric groups, for which the same notation is used; abstract group Z2n); It has a 2n-fold rotoreflection axis, also called 2n-fold improper rotation axis, i.e., the symmetry group contains a combination of a reflection in the horizontal plane and a rotation by an angle 180°/n. Thus, like Dnd, it contains a number of improper rotations without containing the corresponding rotations.
for n=1 we have S2 (1×), also denoted by Ci; this is inversion symmetry.
C2h, [2,2+] (2*) and C2v, [2], (*22) of order 4 are two of the three 3D symmetry group types with the Klein four-group as abstract group. C2v applies e.g. for a rectangular tile wit |
https://en.wikipedia.org/wiki/Nazar%20%28amulet%29 | An eye bead or naẓar (from Arabic , meaning 'sight', 'surveillance', 'attention', and other related concepts) is an eye-shaped amulet believed by many to protect against the evil eye. The term is also used in Azerbaijani, Bengali, Hebrew, Hindi–Urdu, Kurdish, Pashto, Persian, Punjabi, Turkish and other languages. In Turkey, it is known by the name nazar boncuğu (the latter word being a derivative of , "bead" in Turkic, and the former borrowed from Arabic), in Greece is known as μάτι ('eye'). In Persian and Afghan folklore, it is called a cheshm nazar () or nazar qurbāni (). In India and Pakistan, the Hindi-Urdu slogan chashm-e-baddoor is used to ward off the evil eye. In the Indian subcontinent, the phrase nazar lag gai is used to indicate that one has been affected by the evil eye.
The nazar was added to Unicode as in 2018.
Amulet
A typical nazar is made of handmade glass featuring concentric circles or teardrop shapes in dark blue, white, light blue and black, occasionally with a yellow/gold edge. "The bead is made of a mixture of molten glass, iron, copper, water, and salt, ingredients that are thought to shield people from evil."
"According to Turkish belief, blue acts as a shield against evil and even absorbs negativity." In the Middle East and the Mediterranean, "blue eyes are relatively rare, so the ancients believed that people with light eyes, particularly blue eyes, could curse you [one] with just one look. This belief is so ancient, even the Assyrians had turquoise and blue-eye amulets."
Eye bead
The Turkish boncuk (sometimes called a göz boncuğu or eye bead) is a glass bead characterized by a blue glass field with a blue or black dot superimposed on a white or yellow center. Historically old, the blue bead has gained importance as an item of popular culture in Modern Turkey. The bead probably originated in the Mediterranean and is associated with the development of glass making. Written documents and extant beads date as early as the 16th centu |
https://en.wikipedia.org/wiki/Cyanamide | Cyanamide is an organic compound with the formula CN2H2. This white solid is widely used in agriculture and the production of pharmaceuticals and other organic compounds. It is also used as an alcohol-deterrent drug. The molecule features a nitrile group attached to an amino group. Derivatives of this compound are also referred to as cyanamides, the most common being calcium cyanamide (CaCN2).
Tautomers and self-condensations
Containing both a nucleophilic and electrophilic site within the same molecule, cyanamide undergoes various reactions with itself. Cyanamide exists as two tautomers, one with the connectivity N≡C–NH2 and the other with the formula HN=C=NH ("carbodiimide" tautomer). The N≡C–NH2 form dominates, but in a few reactions (e.g. silylation) the diimide form appears to be important.
Cyanamide dimerizes to give 2-cyanoguanidine (dicyandiamide). This dimerization is hindered or reversed by acids and is inhibited by low temperatures. The cyclic trimer is called melamine.
Production
Cyanamide is produced by hydrolysis of calcium cyanamide, which in turn is prepared from calcium carbide via the Frank-Caro process.
CaCN2 + H2O + CO2 → CaCO3 + H2NCN
The conversion is conducted on slurries.
Reactions and uses
Cyanamide can be regarded as a functional single carbon fragment which can react as an electrophile or nucleophile. The main reaction exhibited by cyanamide involves additions of compounds containing an acidic proton. Water, hydrogen sulfide, and hydrogen selenide react with cyanamide to give urea, thiourea, and selenourea, respectively:
H2NCN + H2E → H2NC(E)NH2 (E = O, S, Se)
In this way, cyanamide behaves as a dehydration agent and thus can induce condensation reactions. Alcohols, thiols, and amines react analogously to give alkylisoureas, isothioureas, and guanidines. The anti-ulcer drug cimetidine is generated using such reactivity. Related reactions exploit the bifunctionality of cyanamide to give heterocycles, and this latter reactivity is the b |
https://en.wikipedia.org/wiki/General%20Instrument%20AY-3-8910 | The AY-3-8910 is a 3-voice programmable sound generator (PSG) designed by General Instrument in 1978, initially for use with their 16-bit CP1610 or one of the PIC1650 series of 8-bit microcomputers. The AY-3-8910 and its variants were used in many arcade games—Konami's Gyruss contains five—and pinball machines as well as being the sound chip in the Intellivision and Vectrex video game consoles, and the Amstrad CPC, Oric-1, Colour Genie, Elektor TV Games Computer, MSX, and later ZX Spectrum home computers. It was also used in the Mockingboard and Cricket sound cards for the Apple II and the Speech/Sound Cartridge for the TRS-80 Color Computer.
After General Instrument's spinoff of Microchip Technology in 1987, the chip was sold for a few years under the Microchip brand. It was also manufactured under license by Yamaha (with a selectable clock divider pin and a double-resolution and double-rate volume envelope table) as the YM2149F; the Atari ST uses this version. It produces very similar results to the Texas Instruments SN76489 and was on the market for a similar period.
The chips are no longer made, but functionally-identical clones are still in active production. An unofficial VHDL description is freely available for use with FPGAs.
Description
The AY-3-8910 was essentially a state machine, with the state being set up in a series of sixteen 8-bit registers. These were programmed over an 8-bit bus that was used both for addressing and data by toggling one of the external pins. For instance, a typical setup cycle would put the bus into "address mode" to select a register, and then switch to "data mode" to set the contents of that register. This bus was implemented natively on GI's own CPUs, but it had to be recreated in glue logic or with the help of an additional interface adapter such as the MOS Technology 6522 when the chip was used with the much more common MOS Technology 6502 or Zilog Z80 CPUs.
Six registers controlled the pitches produced in the three pri |
https://en.wikipedia.org/wiki/Move%20by%20nature | In game theory a move by nature is a decision or move in an extensive form game made by a player who has no strategic interests in the outcome. The effect is to add a player, 'Nature', whose practical role is to act as a random number generator. For instance, if a game of Poker requires a dealer to choose which cards a player is dealt, the dealer plays the role of the Nature player.
Fig. 1 shows a signaling game which begins with a move by nature. Moves by nature are an integral part of games of incomplete information. |
https://en.wikipedia.org/wiki/Etch%20pit%20density | The etch pit density (EPD) is a measure for the quality of semiconductor wafers.
Etching
An etch solution is applied on the surface of the wafer where the etch rate is increased at dislocations of the crystal resulting in pits. For GaAs one uses typically molten KOH at 450 degrees Celsius for about 40 minutes in a zirconium crucible. The density of the pits can be determined by optical contrast microscopy. Silicon wafers have usually a very low density of < 100 cm−2 while semi-insulating GaAs wafers have a density on the order of 105 cm−2.
Germanium detectors
High-purity Germanium detectors require the Ge crystals to be grown with a controlled range of dislocation density to reduce impurities. The etch pitch density requirement is typically within the range 103 to 104 cm−2.
Standards
The etch pit density can be determined according to DIN 50454-1 and ASTM F 1404. |
https://en.wikipedia.org/wiki/Emergenesis | In psychology, a trait (or phenotype) is called emergenic if it is the result of a specific combination of several interacting genes (rather than of a simple sum of several independent genes). Emergenic traits will not run in families, but identical twins will share them. Traits such as "leadership", "genius" or certain mental illnesses may be emergenic.
Although one may expect epigenetics to play a significant role in the phenotypic manifestation of twins reared apart, the concordance displayed between them can be attributed to emergenesis. |
https://en.wikipedia.org/wiki/Gold%20leaf | Gold leaf is gold that has been hammered into thin sheets (usually around 0.1 µm thick) by a process known as goldbeating, for use in gilding.
Gold leaf is a type of metal leaf, but the term is rarely used when referring to gold leaf. The term metal leaf is normally used for thin sheets of metal of any color that do not contain any real gold. Gold leaf is available in a wide variety of karats and shades. The most commonly used gold is 22-karat yellow gold. Pure gold is 24 karat. Real, yellow gold leaf is approximately 91.7% pure (i.e. 22-karat) gold.
Traditional water gilding is the most difficult and highly regarded form of gold leafing. It has remained virtually unchanged for hundreds of years and is still done by hand.
History
5,000 years ago, Egyptian artisans recognized the extraordinary durability and malleability of gold and became the first goldbeaters and gilders. They pounded gold using a round stone to create the thinnest leaf possible. Except for the introduction of a cast-iron hammer and a few other innovations, the tools and techniques have remained virtually unchanged for thousands of years.
Gold-leaf forging is a traditional handicraft in Nanjing (China), produced as early as the Three Kingdoms (220 – 280 AD) and Two Jins (266 – 420) dynasties; it was used in Buddha-statue manufacturing and construction. It was widely used in the gilding of Buddha statues and idols and in the construction industry during the Eastern Wu (222-280) and Eastern Jin (266–420) dynasties. During the Qing dynasty (1640-1912), the technology developed, and Nanjing gold leaf was sold overseas. It retains traditional smelting, hand-beating and other techniques, and the gold leaf is pure, uniform and soft. On May 20, 2006, it was included in the first batch of national intangible cultural heritage representative items. Modern gold-leaf artists combine ancient traditional crafts with modern technology to make traditional gold leaf. Forging skills are more sophisticated. |
https://en.wikipedia.org/wiki/Bauschinger%20effect | The Bauschinger effect refers to a property of materials where the material's stress/strain characteristics change as a result of the microscopic stress distribution of the material. For example, an increase in tensile yield strength occurs at the expense of compressive yield strength. The effect is named after German engineer Johann Bauschinger.
While more tensile cold working increases the tensile yield strength, the local initial compressive yield strength after tensile cold working is actually reduced. The greater the tensile cold working, the lower the compressive yield strength.
It is a general phenomenon found in most polycrystalline metals. Based on the cold work structure, two types of mechanisms are generally used to explain the Bauschinger effect:
Local back stresses may be present in the material, which assist the movement of dislocations in the reverse direction. The pile-up of dislocations at grain boundaries and Orowan loops around strong precipitates are two main sources of these back stresses.
When the strain direction is reversed, dislocations of the opposite sign can be produced from the same source that produced the slip-causing dislocations in the initial direction. Dislocations with opposite signs can attract and annihilate each other. Since strain hardening is related to an increased dislocation density, reducing the number of dislocations reduces strength.
The net result is that the yield strength for strain in the opposite direction is less than it would be if the strain had continued in the initial direction.
Mechanism of action
Severe unidirectional cold working results in accumulation of dislocation at barriers to dislocation movement. When stresses are applied in the reverse direction, the dislocations are now aided by the back stresses that were present at the dislocation barriers previously and also because the back stresses at the dislocation barriers in the back are not likely to be strong compared to the previous case. Hence |
https://en.wikipedia.org/wiki/Benedict%E2%80%93Webb%E2%80%93Rubin%20equation | The Benedict–Webb–Rubin equation (BWR), named after Manson Benedict, G. B. Webb, and L. C. Rubin, is an equation of state used in fluid dynamics. Working at the research laboratory of the M. W. Kellogg Company, the three researchers rearranged the Beattie–Bridgeman equation of state and increased the number of experimentally determined constants to eight.
The original BWR equation
,
where is the molar density.
The BWRS equation of state
A modification of the Benedict–Webb–Rubin equation of state by Professor Kenneth E. Starling of the University of Oklahoma:
,
where is the molar density. The 11 mixture parameters (, , etc.) are calculated using the following relations
where and are indices for the components, and the summations go over all components. , , etc. are the parameters for the pure components for the th component, is the mole fraction of the th component, and is an interaction parameter.
Values of the various parameters for 15 substances can be found in Starling's Fluid Properties for Light Petroleum Systems..
The modified BWR equation (mBWR)
A further modification of the Benedict–Webb–Rubin equation of state by Jacobsen and Stewart:
where:
The mBWR equation subsequently evolved into a 32 term version (Younglove and Ely, 1987) with numerical parameters determined by fitting the equation to empirical data for a reference fluid. Other fluids then are described by using reduced variables for temperature and density.
See also
Real gas |
https://en.wikipedia.org/wiki/Source%20Input%20Format | Source Input Format (SIF) defined in MPEG-1, is a video format that was developed to allow the storage and transmission of digital video.
625/50 SIF format (PAL/SECAM) has a resolution of active pixels (half of PAL ) [or active pixels (half of PAL )] and a refresh rate of 25 frames per second.
525/59.94 SIF Format (NTSC) has a resolution of active pixels (half of NTSC ) [or active pixels (half of NTSC )] and a refresh rate of 29.97 frames per second.
When compared to the CCIR 601 specifications, which defines the appropriate parameters for digital encoding of TV signals, SIF can be seen as being reduced by half in all of height, width, frame-rate, and chrominance. SIF video is known as a constrained parameters bitstream.
On square-pixel displays (e.g., computer screens and many modern televisions) SIF images should be rescaled so that the picture covers a 4:3 area, in order to avoid a "stretched" look. So the computer industry has defined "square-pixel SIF" to be 320 x 240 active pixels (QVGA) or 384 x 288 active pixels, with a refresh rate of whatever the computer is capable of supporting. To reach that the SIF content need to be "expanded" horizontally by 12:11 for PAL (PAR = DAR : SAR = : = ) and "reduced" horizontally by 10:11 for NTSC (PAR = DAR : SAR = : = ).
See also
Common Intermediate Format (CIF) |
https://en.wikipedia.org/wiki/Hofstadter%27s%20butterfly | In condensed matter physics, Hofstadter's butterfly is a graph of the spectral properties of non-interacting two-dimensional electrons in a perpendicular magnetic field in a lattice. The fractal, self-similar nature of the spectrum was discovered in the 1976 Ph.D. work of Douglas Hofstadter and is one of the early examples of modern scientific data visualization. The name reflects the fact that, as Hofstadter wrote, "the large gaps [in the graph] form a very striking pattern somewhat resembling a butterfly."
The Hofstadter butterfly plays an important role in the theory of the integer quantum Hall effect and the theory of topological quantum numbers.
History
The first mathematical description of electrons on a 2D lattice, acted on by a perpendicular homogeneous magnetic field, was studied by Rudolf Peierls and his student R. G. Harper in the 1950s.
Hofstadter first described the structure in 1976 in an article on the energy levels of Bloch electrons in perpendicular magnetic fields. It gives a graphical representation of the spectrum of Harper's equation at different frequencies. One key aspect of the mathematical structure of this spectrum – the splitting of energy bands for a specific value of the magnetic field, along a single dimension (energy) – had been previously mentioned in passing by Soviet physicist Mark Azbel in 1964 (in a paper cited by Hofstadter), but Hofstadter greatly expanded upon that work by plotting all values of the magnetic field against all energy values, creating the two-dimensional plot that first revealed the spectrum's uniquely recursive geometric properties.
Written while Hofstadter was at the University of Oregon, his paper was influential in directing further research. It predicted on theoretical grounds that the allowed energy level values of an electron in a two-dimensional square lattice, as a function of a magnetic field applied perpendicularly to the system, formed what is now known as a fractal set. That is, the distributio |
https://en.wikipedia.org/wiki/Context-sensitive%20help | Context-sensitive help is a kind of online help that is obtained from a specific point in the state of the software, providing help for the situation that is associated with that state.
Context-sensitive help, as opposed to general online help or online manuals, does not need to be accessible for reading as a whole. Each topic is supposed to describe extensively one state, situation, or feature of the software.
Context-sensitive help can be implemented using tooltips, which either provide a terse description of a GUI widget or display a complete topic from the help file. Other commonly used ways to access context-sensitive help start by clicking a button. One way uses a per widget button that displays the help immediately. Another way changes the pointer shape to a question mark, and then, after the user clicks a widget, the help appears.
Context-sensitive help is most used in, but is not limited to, GUI environments. Examples include Apple's System 7 Balloon help, Microsoft's WinHelp, OS/2's INF Help or Sun's JavaHelp. An example of context sensitive help familiar to most Wikipedia users are the tooltips that show previews of links within articles, helping readers to determine whether following the link is valuable prior to shifting pages.
A similar topic is embedded help, which can be thought of as a "deeper" context-sensitive help. It generally goes beyond basic explanations or manual clicks by either detecting a user's need for help or offering a guided explanation in situ. Embedded help is not to be confused with a software wizard.
See also
Balloon Help
Tooltip
AnswerDash
Notes |
https://en.wikipedia.org/wiki/Return%20on%20net%20assets | The return on net assets (RONA) is a measure of financial performance of a company which takes the use of assets into account. Higher RONA means that the company is using its assets and working capital efficiently and effectively. RONA is used by investors to determine how well management is utilizing assets.
Basic formulae
where
In a manufacturing sector, this is also calculated as:
See also
Financial ratio |
https://en.wikipedia.org/wiki/Ancestry.com | Ancestry.com LLC is an American genealogy company based in Lehi, Utah. The largest for-profit genealogy company in the world, it operates a network of genealogical, historical records, and related genetic genealogy websites.
In November 2018, the company was said to have provided access to approximately 10 billion historical records, to have 3 million paying subscribers, and to have sold 18 million DNA kits to customers. By 2022, this number had risen to 30 billion records according to the company. On December 4, 2020, The Blackstone Group acquired the company in a deal valued at $4.7 billion.
History
Ancestry
1990–1999
In 1990, Paul Brent Allen (not to be confused with Microsoft cofounder Paul Allen or the Allen Holdings CEO Paul Allen) and Dan Taggart, two Brigham Young University graduates, founded Infobases and began offering Latter-day Saints (LDS) publications on floppy disks. In 1988, Allen had worked at Folio Corporation, founded by his brother Curt and his brother-in-law Brad Pelo.
The service was initially to help members of the church to research their ancestors to support the church's practice of conducting baptisms for dead relatives/ancestors into the church.
Infobases' first products were floppy disks and compact disks sold from the back seat of the founders' car. In 1994, Infobases was named among Inc. magazine's 500 fastest-growing companies. Their first offering on CD was the LDS Collectors Edition, released in April 1995, selling for $299.95, which was offered in an online version in August 1995. Ancestry officially went online with the launch of Ancestry.com in 1996.
On January 1, 1997, Infobases' parent company, Western Standard Publishing, purchased Ancestry, Inc., publisher of Ancestry magazine and genealogy books. Western Standard Publishing's CEO was Joseph A. Cannon, one of the principal owners of Geneva Steel.
In July 1997, Allen and Taggart purchased Western Standard's interest in Ancestry, Inc. At the time, Brad Pelo was presiden |
https://en.wikipedia.org/wiki/Google%20Summer%20of%20Code | The Google Summer of Code, often abbreviated to GSoC, is an international annual program in which Google awards stipends to contributors who successfully complete a free and open-source software coding project during the summer. , the program is open to anyone aged 18 or over, no longer just students and recent graduates. It was first held from May to August 2005. Participants get paid to write software, with the amount of their stipend depending on the purchasing power parity of the country where they are located. Project ideas are listed by host organizations involved in open-source software development, though students can also propose their own project ideas.
The idea for the Summer of Code came directly from Google's founders, Sergey Brin and Larry Page. From 2007 until 2009 Leslie Hawthorn, who has been involved in the project since 2006, was the program manager. From 2010 until 2015, Carol Smith was the program manager. In 2016, Stephanie Taylor took over management of the program.
Overview
Each year, the program follows a timeline. First, open-source organizations apply to participate. If accepted, each organization provides a list of initial project ideas and invites contributors to their development communities. Contributors who meet the eligibility criteria then submit up to 3 proposals that detail the software-coding projects that interest them. These applications are then evaluated by the corresponding mentoring organization, with mentors and organizational administrators reviewing the applications and deciding how many "slots" to request from Google, and which proposals to accept. Google allocates slots to each organization, taking into account organizational capacity, mentoring history, and the number of applications the organization has received. Finally, organizations select the top proposals to fill their slots and Google verifies eligibility before announcing accepted contributors. In the event of a single contributors being selected by more th |
https://en.wikipedia.org/wiki/I%2A | i* (pronounced "i star") or i* framework is a modeling language suitable for an early phase of system modeling in order to understand the problem domain. i* modeling language allows to model both as-is and to-be situations. The name i* refers to the notion of distributed intentionality which underlines the framework. It is an approach originally developed for modelling and reasoning about organizational environments and their information systems composed of heterogeneous actors with different, often competing, goals that depend on each other to undertake their tasks and achieve these goals. It covers both actor-oriented and Goal modeling. i* models answer the question WHO and WHY, not what.
In contrast, the UML Use case approach covers only functional goals, with actors directly involved in operations (typically with software). The KAOS approach covers goals of all types but is less concerned with the intentionality of actors.
Elements
The model describes dependencies among actors. There are four elements to describe them: goal, soft goal, task and resource. The central concept in i* is in fact that of the intentional actor. Organizational actors are viewed as having intentional properties such as goals, beliefs, abilities, and commitments (concept of distributed intentionality). Actors depend on each other for goals to be achieved, tasks to be performed and resources to be furnished. By depending on others, an actor may be able to achieve goals that are difficult or impossible to achieve on its own; on the other hand, an actor becomes vulnerable if the depended-on actors do not deliver. Actors are strategic in the sense that they are concerned about opportunities and vulnerabilities, and seek rearrangement of their environments that would better serve their interests by restructuring intentional relationships.
Models
i* framework consists of two main modeling components:
Strategic Dependency model (SD)
An SD model describes a network of dependency relationshi |
https://en.wikipedia.org/wiki/Square%20root%20of%20a%20matrix | In mathematics, the square root of a matrix extends the notion of square root from numbers to matrices. A matrix is said to be a square root of if the matrix product is equal to .
Some authors use the name square root or the notation only for the specific case when is positive semidefinite, to denote the unique matrix that is positive semidefinite and such that (for real-valued matrices, where is the transpose of ).
Less frequently, the name square root may be used for any factorization of a positive semidefinite matrix as , as in the Cholesky factorization, even if . This distinct meaning is discussed in .
Examples
In general, a matrix can have several square roots. In particular, if then as well.
The 2×2 identity matrix has infinitely many square roots. They are given by
and
where are any numbers (real or complex) such that .
In particular if is any Pythagorean triple—that is, any set of positive integers such that , then
is a square root matrix of which is symmetric and has rational entries.
Thus
Minus identity has a square root, for example:
which can be used to represent the imaginary unit and hence all complex numbers using 2×2 real matrices, see Matrix representation of complex numbers.
Just as with the real numbers, a real matrix may fail to have a real square root, but have a square root with complex-valued entries.
Some matrices have no square root. An example is the matrix
While the square root of a nonnegative integer is either again an integer or an irrational number, in contrast an integer matrix can have a square root whose entries are rational, yet non-integral, as in examples above.
Positive semidefinite matrices
A symmetric real n × n matrix is called positive semidefinite if for all (here denotes the transpose, changing a column vector into a row vector).
A square real matrix is positive semidefinite if and only if for some matrix .
There can be many different such matrices .
A positive semidefinite matrix |
https://en.wikipedia.org/wiki/Crawler%20%28BEAM%29 | In BEAM robotics, a crawler is a robot that has a mode of locomotion by tracks or by transferring the robot's body on limbs or appendages. These do not drag parts of their body on the ground.
In the original paper "living machines" from 1995, two types of robots were introduced which was the Walkman (a simple crawler) and Spyder, which is a more elaborated legged robot. The difference between a walker and a crawler is, that the crawler is more primitive. It has robot legs and can move forward on the carpet but the legs don't have dedicated joints for articulated movements. Instead they are mounted directly on the robot's base.
The design of a crawler robot isn't specified in detail and each robot engineer is allowed to build their own version. Sometimes, crawling robots are equipped with dedicated microcontrollers plus a radio controlled chipset while in other implementations a minimalist approach is used. What all these robots have in common is, that they are following the philosophy of Biology, Electronics, Aesthetics and Mechanics which is about imitating biological bugs.
A possible alternative control over teleoperation is a nv network which is a specialized form of a central pattern generator. This is a pseudorandom number generator which is producing an oscillating signal. It moves the legs similar to a clockwork.
Genera
Turbots: Rolls over and over as a mode of locomotion via arms or flagella.
Inchworms: Driven mode of locomotion via the robot's body undulating; this undulation moves part of the body ahead, while the rest of the chassis is on the ground.
Tracked robots: "Track-ed" wheel locomotion; tank-like action. |
https://en.wikipedia.org/wiki/Term%20indexing | In computer science, a term index is a data structure to facilitate fast lookup of terms and clauses in a logic program, deductive database, or automated theorem prover.
Overview
Many operations in automatic theorem provers require search in huge collections of terms and clauses. Such operations typically fall into the following scheme. Given a collection of terms (clauses) and a query term (clause) , find in some/all terms related to according to a certain retrieval condition. Most interesting retrieval conditions are formulated as existence of a substitution that relates in a special way the query and the retrieved objects . Here is a list of retrieval conditions frequently used in provers:
term is unifiable with term , i.e., there exists a substitution , such that =
term is an instance of , i.e., there exists a substitution , such that =
term is a generalisation of , i.e., there exists a substitution , such that =
clause subsumes clause , i.e., there exists a substitution , such that is a subset/submultiset of
clause is subsumed by , i.e., there exists a substitution , such that is a subset/submultiset of
More often than not, we are actually interested in finding the appropriate
substitutions explicitly, together with the retrieved terms ,
rather than just in establishing existence of such substitutions.
Very often the sizes of term sets to be searched are large,
the retrieval calls are frequent and the retrieval condition test
is rather complex. In such situations linear search in , when the retrieval
condition is tested on every term from , becomes prohibitively costly.
To overcome this problem, special data structures, called indexes, are
designed in order to support fast retrieval. Such data structures,
together with the accompanying algorithms for index maintenance
and retrieval, are called term indexing techniques.
Classic indexing techniques
discrimination trees
substitution trees
path indexing
Substitution trees |
https://en.wikipedia.org/wiki/Epithelial%E2%80%93mesenchymal%20transition | The epithelial–mesenchymal transition (EMT) is a process by which epithelial cells lose their cell polarity and cell–cell adhesion, and gain migratory and invasive properties to become mesenchymal stem cells; these are multipotent stromal cells that can differentiate into a variety of cell types. EMT is essential for numerous developmental processes including mesoderm formation and neural tube formation. EMT has also been shown to occur in wound healing, in organ fibrosis and in the initiation of metastasis in cancer progression.
Introduction
Epithelial–mesenchymal transition was first recognized as a feature of embryogenesis by Betty Hay in the 1980s. EMT, and its reverse process, MET (mesenchymal-epithelial transition) are critical for development of many tissues and organs in the developing embryo, and numerous embryonic events such as gastrulation, neural crest formation, heart valve formation, secondary palate development, and myogenesis. Epithelial and mesenchymal cells differ in phenotype as well as function, though both share inherent plasticity. Epithelial cells are closely connected to each other by tight junctions, gap junctions and adherens junctions, have an apico-basal polarity, polarization of the actin cytoskeleton and are bound by a basal lamina at their basal surface. Mesenchymal cells, on the other hand, lack this polarization, have a spindle-shaped morphology and interact with each other only through focal points. Epithelial cells express high levels of E-cadherin, whereas mesenchymal cells express those of N-cadherin, fibronectin and vimentin. Thus, EMT entails profound morphological and phenotypic changes to a cell.
Based on the biological context, EMT has been categorized into 3 types: developmental (Type I), fibrosis and wound healing (Type II), and cancer (Type III).
Inducers
Loss of E-cadherin is considered to be a fundamental event in EMT. Many transcription factors (TFs) that can repress E-cadherin directly or indirectly can be consi |
https://en.wikipedia.org/wiki/Roberval%20balance | The Roberval balance is a weighing scale presented to the French Academy of Sciences by the French mathematician Gilles Personne de Roberval in 1669.
In this scale, two identical horizontal beams are attached, one directly above the other, to a vertical column, which is attached to a stable base. On each side, both horizontal beams are attached to a vertical beam. The six attachment points are pivots. Two horizontal plates, suitable for placing objects to be weighed, are fixed to the top of the two vertical beams. An arrow on the lower horizontal beam (and perpendicular to it) and a mark on the vertical column may be added to aid in leveling the scale.
The object to be weighed is placed on one plate, and calibrated masses are added to and subtracted from the other plate until level is reached. The mass of the object is equal to the mass of the calibrated masses regardless of where on the plates the items are placed. Since the vertical beams are always vertical, and the weighing platforms always horizontal, the potential energy lost by a weight as its platform goes down a certain distance will always be the same, so it makes no difference where the weight is placed. For maximum accuracy, Roberval balances require that their top fulcrum be placed on the line between the left and right pivot so that tipping will not result in the net transfer of weight to either the left or right side of the scale: a fulcrum placed below the ideal pivot point will tend to cause a net shift in the direction of any downward-moving vertical column (in a kind of positive feedback loop); likewise, a fulcrum placed above this point will tend to level out the arms of the balance rather than respond to small changes in weight (in a negative feedback loop).
An off-center weight on the plate exerts a downward force and a torque on the vertical column supporting the plate. The downward force is carried by the bearing at the top beam in most balance scales, the lower beam just being supported h |
https://en.wikipedia.org/wiki/Peripheral%20blood%20mononuclear%20cell | A peripheral blood mononuclear cell (PBMC) is any peripheral blood cell having a round nucleus. These cells consist of lymphocytes (T cells, B cells, NK cells) and monocytes, whereas erythrocytes and platelets have no nuclei, and granulocytes (neutrophils, basophils, and eosinophils) have multi-lobed nuclei. In humans, lymphocytes make up the majority of the PBMC population, followed by monocytes, and only a small percentage of dendritic cells.
These cells can be extracted from whole blood using ficoll, a hydrophilic polysaccharide that separates layers of blood, and gradient centrifugation, which will separate the blood into a top layer of plasma, followed by a layer of PBMCs (buffy coat) and a bottom fraction of polymorphonuclear cells (such as neutrophils and eosinophils) and erythrocytes. The polymorphonuclear cells can be further isolated by lysing the red blood cells. Basophils are sometimes found in both the denser and the PBMC fractions.
Clinical significance
Infections
Recent studies indicate that PBMCs may be susceptible to pathogenic infections, such as Ureaplasma parvum and urealiticum, Mycoplasma genitalium and hominis and Chlamydia trachomatis infections. PBMCs may be also susceptible to viral infections. Indeed, footprints of JC polyomavirus and Merkel cell polyomavirus have been detected in PBMCs from pregnant women and women affected by spontaneous abortion.
Research uses
Many scientists conducting research in the fields of immunology (including auto-immune disorders), infectious disease, hematological malignancies, vaccine development, transplant immunology, and high-throughput screening are frequent users of PBMCs. In many cases, PBMCs are derived from blood banks. PBMC fraction also contains progenitor populations, as demonstrated by methylcellulose based colony forming assays.
PBMCs have been thought to be an important route of vaccination. PBMCs from cancer patients can be extracted and cultured in vitro. Subsequently, PBMCs are challen |
https://en.wikipedia.org/wiki/Simplified%20perturbations%20models | Simplified perturbations models are a set of five mathematical models (SGP, SGP4, SDP4, SGP8 and SDP8) used to calculate orbital state vectors of satellites and space debris relative to the Earth-centered inertial coordinate system. This set of models is often referred to collectively as SGP4 due to the frequency of use of that model particularly with two-line element sets produced by NORAD and NASA.
These models predict the effect of perturbations caused by the Earth’s shape, drag, radiation, and gravitation effects from other bodies such as the sun and moon. Simplified General Perturbations (SGP) models apply to near earth objects with an orbital period of less than 225 minutes. Simplified Deep Space Perturbations (SDP) models apply to objects with an orbital period greater than 225 minutes, which corresponds to an altitude of 5,877.5 km, assuming a circular orbit.
The SGP4 and SDP4 models were published along with sample code in FORTRAN IV in 1988 with refinements over the original model to handle the larger number of objects in orbit since. SGP8/SDP8 introduced additional improvements for handling orbital decay.
The SGP4 model has an error ~1 km at epoch and grows at ~1–3 km per day. This data is updated frequently in NASA and NORAD sources due to this error. The original SGP model was developed by Kozai in 1959, refined by Hilton & Kuhlman in 1966 and was originally used by the National Space Surveillance Control Center (and later the United States Space Surveillance Network) for tracking of objects in orbit. The SDP4 model has an error of 10 km at epoch.
Deep space models SDP4 and SDP8 use only 'simplified drag' equations. Accuracy is not a great concern here as high drag satellite cases do not remain in "deep space" for very long as the orbit quickly becomes lower and near circular. SDP4 also adds Lunar–Solar gravity perturbations to all orbits, and Earth resonance terms specifically for 24-hour geostationary and 12-hour Molniya orbits.
Additional |
https://en.wikipedia.org/wiki/Geiger%E2%80%93Nuttall%20law | In nuclear physics, the Geiger–Nuttall law or Geiger–Nuttall rule relates the decay constant of a radioactive isotope with the energy of the alpha particles emitted. Roughly speaking, it states that short-lived isotopes emit more energetic alpha particles than long-lived ones.
The relationship also shows that half-lives are exponentially dependent on decay energy, so that very large changes in half-life make comparatively small differences in decay energy, and thus alpha particle energy. In practice, this means that alpha particles from all alpha-emitting isotopes across many orders of magnitude of difference in half-life, all nevertheless have about the same decay energy.
Formulated in 1911 by Hans Geiger and John Mitchell Nuttall as a relation between the decay constant and the range of alpha particles in air, in its modern form the Geiger–Nuttall law is
where is the half-life, E the total kinetic energy (of the alpha particle and the daughter nucleus), and A and B are coefficients that depend on the isotope's atomic number Z.
The law works best for nuclei with even atomic number and even atomic mass. The trend is still there for even-odd, odd-even, and odd-odd nuclei but is not as pronounced.
Cluster decays
The Geiger–Nuttall law has even been extended to describe cluster decays,
decays where atomic nuclei larger than helium are released, e.g. silicon and carbon.
Derivation
A simple way to derive this law is to consider an alpha particle in the atomic nucleus as a particle in a box. The particle is in a bound state because of the presence of the strong interaction potential. It will constantly bounce from one side to the other, and due to the possibility of quantum tunneling by the wave through the potential barrier, each time it bounces, there will be a small likelihood for it to escape.
A knowledge of this quantum mechanical effect enables one to obtain this law, including coefficients, via direct calculation. This calculation was first performed by |
https://en.wikipedia.org/wiki/Xubuntu | Xubuntu () is a Canonical Ltd.–recognized, community-maintained derivative of the Ubuntu operating system. The name Xubuntu is a portmanteau of Xfce and Ubuntu, as it uses the Xfce desktop environment, instead of Ubuntu's customized GNOME desktop.
Xubuntu seeks to provide "a light, stable and configurable desktop environment with conservative workflows" using Xfce components. Xubuntu is intended for both new and experienced Linux users. Rather than explicitly targeting low-powered machines, it attempts to provide "extra responsiveness and speed" on existing hardware.
History
Xubuntu was originally intended to be released at the same time as Ubuntu 5.10 Breezy Badger, 13 October 2005, but the work was not complete by that date. Instead the Xubuntu name was used for the xubuntu-desktop metapackage available through the Synaptic Package Manager which installed the Xfce desktop.
The first official Xubuntu release, led by Jani Monoses, appeared on 1 June 2006, as part of the Ubuntu 6.06 Dapper Drake line, which also included Kubuntu and Edubuntu.
Cody A.W. Somerville developed a comprehensive strategy for the Xubuntu project named the Xubuntu Strategy Document. This document was approved by the Ubuntu Community Council in 2008.
In February 2009 Mark Shuttleworth agreed that an official LXDE version of Ubuntu, Lubuntu, would be developed. The LXDE desktop uses the Openbox window manager and, like Xubuntu, is intended to be a low-system-requirement, low-RAM environment for netbooks, mobile devices and older PCs and will compete with Xubuntu in that niche.
In November 2009, Cody A.W. Somerville stepped down as the project leader and made a call for nominations to help find a successor. Lionel Le Folgoc was confirmed by the Xubuntu community as the new project leader on 10 January 2010 and requested the formation of an official Xubuntu council. , discussions regarding the future of Xubuntu's governance and the role a council might play in it were still ongoing.
In Ma |
https://en.wikipedia.org/wiki/Hyperion%20%28computer%29 | The Hyperion is an early portable computer that vied with the Compaq Portable to be the first portable IBM PC compatible. It was marketed by Infotech Cie of Ottawa, a subsidiary of Bytec Management Corp., who acquired the designer and manufacturer Dynalogic Corporation, in January 1983. In 1984, the design was licensed by Commodore International in a move that was forecast as a "radical shift of position" and a signal that Commodore would soon dominate the PC compatible market. Despite computers being "hand-assembled from kits" provided by Bytec and displayed alongside the Commodore 900 at a German trade show as their forthcoming first portable computer, it was never sold by Commodore and some analysts downplayed the pact. The Hyperion was shipped in January 1983 at C$4995, two months ahead of the Compaq Portable.
Brand name
The name "Hyperion" was invented by Taylor-Sprules Corporation in Toronto. They also designed the retail packaging, all marketing materials and the tradeshow exhibit at Comdex in Atlantic City where Hyperion was first introduced in 1982. Two prototypes were shown. The amber graphics screens, and a built-in modem, were notable features that attracted comment at the show.
Design
The machine featured 256 KB RAM, dual 360 KB 5.25" floppy disk drives, a graphics card compatible with both CGA and HGC, a video-out jack, a built-in 7-inch amber CRT, 300 bit/s modem, and an acoustic coupler. It included a version of MS-DOS called H-DOS and bundled word processor, database, and modem software. While the Hyperion weighed just eighteen pounds (8.2 kg), or about 2/3 the weight of the Compaq, it was not as reliable or as IBM compatible and was discontinued within two years. One significant difference from the IBM system was the use of a Zilog Z80-SIO chip instead of a National Semiconductor 8250 for serial communications.
Interface
H-DOS was remarkable and is of historical significance because it featured a simple menu system. The through keys benea |
https://en.wikipedia.org/wiki/Logarithm%20of%20a%20matrix | In mathematics, a logarithm of a matrix is another matrix such that the matrix exponential of the latter matrix equals the original matrix. It is thus a generalization of the scalar logarithm and in some sense an inverse function of the matrix exponential. Not all matrices have a logarithm and those matrices that do have a logarithm may have more than one logarithm. The study of logarithms of matrices leads to Lie theory since when a matrix has a logarithm then it is in an element of a Lie group and the logarithm is the corresponding element of the vector space of the Lie algebra.
Definition
The exponential of a matrix A is defined by
.
Given a matrix B, another matrix A is said to be a matrix logarithm of .
Because the exponential function is not bijective for complex numbers (e.g. ), numbers can have multiple complex logarithms, and as a consequence of this, some matrices may have more than one logarithm, as explained below. If the matrix logarithm of exists and is unique, then it is written as in which case
Power series expression
If B is sufficiently close to the identity matrix, then a logarithm of B may be computed by means of the following power series:
.
Specifically, if , then the preceding series converges and .
Example: Logarithm of rotations in the plane
The rotations in the plane give a simple example. A rotation of angle α around the origin is represented by the 2×2-matrix
For any integer n, the matrix
is a logarithm of A.
⇔
where
…
qed.
Thus, the matrix A has infinitely many logarithms. This corresponds to the fact that the rotation angle is only determined up to multiples of 2π.
In the language of Lie theory, the rotation matrices A are elements of the Lie group SO(2). The corresponding logarithms B are elements of the Lie algebra so(2), which consists of all skew-symmetric matrices. The matrix
is a generator of the Lie algebra so(2).
Existence
The question of whether a matrix has a logarithm has the easiest answer when con |
https://en.wikipedia.org/wiki/Geomechanics | Geomechanics (from the Greek prefix geo- meaning "earth"; and "mechanics") is the study of the mechanical state of the Earth's crust and the processes occurring in it under the influence of natural physical factors. It involves the study of the mechanics of soil and rock.
Background
The two main disciplines of geomechanics are soil mechanics and rock mechanics. Former deals with the soil behaviour from a small scale to a landslide scale. The latter deals with issues in geosciences related to rock mass characterization and rock mass mechanics, such as applied to petroleum, mining and civil engineering problems, such as borehole stability, tunnel design, rock breakage, slope stability, foundations, and rock drilling.
Many aspects of geomechanics overlap with parts of geotechnical engineering, engineering geology, and geological engineering. Modern developments relate to seismology, continuum mechanics, discontinuum mechanics, and transport phenomena.
Reservoir Geomechanics
In the petroleum industry geomechanics is used to:
predict pore pressure
establish the integrity of the cap rock
evaluate reservoir properties
determine in-situ rock stress
evaluate the wellbore stability
calculate the optimal trajectory of the borehole
predict and control sand occurrence in the well
analyze the validity of drilling on depression
characterize fractured reservoirs
increase the efficiency of the development of fractured reservoirs
evaluate hydraulic fractures stability
evaluate the effect of liquid and steam injection into the reservoir
analyze surface subsidence
evaluate shear deformation and casing collapse
To put into practice the geomechanics capabilities mentioned above, it is necessary to create a Geomechanical Model of the Earth (GEM) which consists of six key components that can be both calculated and estimated using field data:
Vertical stress, δv (often called geostatic pressure)
Maximum horizontal stress, δHmax
Minimum horizontal stress, δHmin
Stres |
https://en.wikipedia.org/wiki/Conditioner%20%28chemistry%29 | In chemistry and materials science, a conditioner is a substance or process that improves the quality of a given material. Conditioning agents used in skincare products are also known as moisturizers, and usually are composed of various oils and lubricants. One method of their use is as a coating of the substrate to alter the feel and appearance. For cosmetic products, this effect is a temporary one but can help to protect skin and hair from further damage.
In cosmetic products the types of conditioning agents used are as follows:
Emollients, usually oils, fats, waxes or silicones, which are hydrophobic molecules of natural or synthetic origin that coat the skin or hair and provide an occlusive surface that helps prevent further loss of moisture as well as providing slip and lubricity
Humectants, typically polyols or glycols, that can hydrogen bond with water in the skin and hair and reduce water loss
Cationic surfactants or polymers that are substantive to the slightly negatively-charged skin and hair and provide a film on the hair that limits further damage
Fatty alcohols which are amphiphilic and provide a hydrophobic coating to skin and hair as well as building a lamellar structure in the cosmetic product that builds viscosity as well as improving product stability
See also
Chemical conditioning |
https://en.wikipedia.org/wiki/Nordtvedt%20effect | In theoretical astrophysics, the Nordtvedt effect refers to the relative motion between the Earth and the Moon that would be observed if the gravitational self-energy of a body contributed differently to its gravitational mass than to its inertial mass. If observed, the Nordtvedt effect would violate the strong equivalence principle, which indicates that an object's movement in a gravitational field does not depend on its mass or composition. No evidence of the effect has been found.
The effect is named after Kenneth L. Nordtvedt, who first demonstrated that some theories of gravity suggest that massive bodies should fall at different rates, depending upon their gravitational self-energy.
Nordtvedt then observed that if gravity did in fact violate the strong equivalence principle, then the more-massive Earth should fall towards the Sun at a slightly different rate than the Moon, resulting in a polarization of the lunar orbit. To test for the existence (or absence) of the Nordtvedt effect, scientists have used the Lunar Laser Ranging experiment, which is capable of measuring the distance between the Earth and the Moon with near-millimetre accuracy. Thus far, the results have failed to find any evidence of the Nordtvedt effect, demonstrating that if it exists, the effect is exceedingly weak. Subsequent measurements and analysis to even higher precision have improved constraints on the effect. Measurements of Mercury's orbit by the MESSENGER Spacecraft have further refined the Nordvedt effect to be below an even smaller scale.
A wide range of scalar–tensor theories have been found to naturally lead to a tiny effect only, at present epoch. This is due to a generic attractive mechanism that takes place during the cosmic evolution of the universe. Other screening mechanisms (chameleon, pressuron, Vainshtein etc.) could also be at play.
See also
Galileo's Leaning Tower of Pisa experiment |
https://en.wikipedia.org/wiki/Standard%20test%20image | A standard test image is a digital image file used across different institutions to test image processing and image compression algorithms. By using the same standard test images, different labs are able to compare results, both visually and quantitatively.
The images are in many cases chosen to represent natural or typical images that a class of processing techniques would need to deal with. Other test images are chosen because they present a range of challenges to image reconstruction algorithms, such as the reproduction of fine detail and textures, sharp transitions and edges, and uniform regions.
Historical origins
Test images as transmission system calibration material probably date back to the original Paris to Lyon fax link. Analogue Fax equipment (and photographic equipment for the printing trade) were the largest user groups of the standardized image for calibration technology until the coming of television and digital image transmission systems.
Common test image resolutions
The standard resolution of the images is usually 512×512 or 720×576. Most of these images are available as TIFF files from the University of Southern California's Signal and Image Processing Institute. Kodak has released 768×512 images, available as PNGs, that was originally on Photo CD with higher resolution, that are widely used for comparing image compression techniques.
See also
Carole Hersee
FERET database (DARPA/NIST face recognition database)
Lenna
List of common 3D test models |
https://en.wikipedia.org/wiki/Light-harvesting%20complexes%20of%20green%20plants | The light-harvesting complex (or antenna complex; LH or LHC) is an array of protein and chlorophyll molecules embedded in the thylakoid membrane of plants and cyanobacteria, which transfer light energy to one chlorophyll a molecule at the reaction center of a photosystem.
The antenna pigments are predominantly chlorophyll b, xanthophylls, and carotenes. Chlorophyll a is known as the core pigment. Their absorption spectra are non-overlapping and broaden the range of light that can be absorbed in photosynthesis. The carotenoids have another role as an antioxidant to prevent photo-oxidative damage of chlorophyll molecules. Each antenna complex has between 250 and 400 pigment molecules and the energy they absorb is shuttled by resonance energy transfer to a specialized chlorophyll-protein complex known as the reaction center of each photosystem. The reaction center initiates a complex series of chemical reactions that capture energy in the form of chemical bonds.
For photosystem II, when either of the two chlorophyll a molecules at the reaction center absorb energy, an electron is excited and transferred to an electron acceptor molecule, pheophytin, leaving the chlorophyll a in an oxidized state. The oxidised chlorophyll a replaces the electrons by photolysis that involves the oxidation of water molecules to oxygen, protons and electrons.
The N-terminus of the chlorophyll a-b binding protein extends into the stroma where it is involved with adhesion of granal membranes and photo-regulated by reversible phosphorylation of its threonine residues. Both these processes are believed to mediate the distribution of excitation energy between photosystems I and II.
This family also includes the photosystem II protein PsbS, which plays a role in energy-dependent quenching that increases thermal dissipation of excess absorbed light energy in the photosystem.
LH 1
Light-harvesting complex I is permanently bound to photosystem I via the plant-specific subunit PsaG. It is made u |
https://en.wikipedia.org/wiki/SBCS | SBCS, or single-byte character set, is used to refer to character encodings that use exactly one byte for each graphic character. An SBCS can accommodate a maximum of 256 symbols, and is useful for scripts that do not have many symbols or accented letters such as the Latin, Greek and Cyrillic scripts used mainly for European languages. Examples of SBCS encodings include ISO/IEC 646, the various ISO 8859 encodings, and the various Microsoft/IBM code pages.
The term SBCS is commonly contrasted against the terms DBCS (double-byte character set) and TBCS (triple-byte character set), as well as MBCS (multi-byte character set). The multi-byte character sets are used to accommodate languages with scripts that have large numbers of characters and symbols, predominantly Asian languages such as Chinese, Japanese, and Korean. These are sometimes referred to by the acronym CJK. In these computing systems, SBCSs are traditionally associated with half-width characters, so-called because such SBCS characters would traditionally occupy half the width of a DBCS character on a fixed-width computer terminal or text screen.
See also
DBCS
TBCS
MBCS
Variable-width encoding |
https://en.wikipedia.org/wiki/Portable%20storage%20device | A portable storage device (PSD) is a compact plug-and-play mass storage device designed to hold a large volume of digital data of any kind. This is slightly different from a portable media player, which is designed to only store music and video files that its internal reader softwares can play.
Most modern PSDs are dedicated solid state drives (SSD) that are connected to a computer and powered via USB ports. Some PSDs, usually those from before the wide adoption of SSDs, are modified hard disk drives via the installation of a disk enclosure, and require an additional AC adapter as the power required to operate the drive typically exceeds that can be provided by the USB port.
PSDs, while much bigger and heavier than ultracompact flash drives such as USB flash drives and memory cards, offer significantly more external storage capacities, yet are still convenient enough for carrying around when travelling or as a readily accessible offline backup storage option, especially in situations where online storage alternatives such as network-attached storage and cloud storage are unavailable, unreliable or unsafe.
Photography
One type of data that may be stored is digital photographs (RAW data), transferred from a digital camera.
Many PSDs will connect directly to a camera and copy the images, or they may provide a slot for a memory card to plug in, with or without a card reader device. Some early models allow the user to review the images on a colour screen, but at the top end of the market.
See also
Computer storage
Mass Storage Digital Class (MSDC) |
https://en.wikipedia.org/wiki/Electronic%20symbol | An electronic symbol is a pictogram used to represent various electrical and electronic devices or functions, such as wires, batteries, resistors, and transistors, in a schematic diagram of an electrical or electronic circuit. These symbols are largely standardized internationally today, but may vary from country to country, or engineering discipline, based on traditional conventions.
Standards for symbols
The graphic symbols used for electrical components in circuit diagrams are covered by national and international standards, in particular:
IEC 60617 (also known as BS 3939).
There is also IEC 61131-3 – for ladder-logic symbols.
JIC JIC (Joint Industrial Council) symbols as approved and adopted by the NMTBA (National Machine Tool Builders Association). They have been extracted from the Appendix of the NMTBA Specification EGPl-1967.
ANSI Y32.2-1975 (also known as IEEE Std 315-1975 or CSA Z99-1975).
IEEE Std 91/91a: graphic symbols for logic functions (used in digital electronics). It is referenced in ANSI Y32.2/IEEE Std 315.
Australian Standard AS 1102 (based on a slightly modified version of IEC 60617; withdrawn without replacement with a recommendation to use IEC 60617).
The number of standards leads to confusion and errors.
Symbols usage is sometimes unique to engineering disciplines, and national or local variations to international standards exist. For example, lighting and power symbols used as part of architectural drawings may be different from symbols for devices used in electronics.
Common electronic symbols
Symbols shown are typical examples, not a complete list.
Traces
Grounds
The shorthand for ground is GND. Optionally, the triangle in the middle symbol may be filled in.
Sources
Resistors
It is very common for potentiometer and rheostat symbols to be used for many types of variable resistors, including trimmers.
Capacitors
Diodes
Optionally, the triangle in these symbols may be filled in. Note: The words anode and cathode typically |
https://en.wikipedia.org/wiki/Intel%20Turbo%20Memory | Intel Turbo Memory is a technology introduced by Intel Corporation that uses NAND flash memory modules to reduce the time it takes for a computer to power up, access programs, and write data to the hard drive. During development, the technology was codenamed Robson. It is supported by most of the Core 2 Mobile chipset series, but not by the newer Core i Series mobile chipsets.
Overview
The technology was publicly introduced on October 24, 2005, at the Intel Developer Forum (IDF) in Taiwan when a laptop that booted up almost immediately was demonstrated. The technology attempts to decrease hard drive usage by moving frequently accessed data over to the flash memory. Flash memory can be accessed faster than hard drives and requires less power to operate, thereby allowing laptops to operate faster while also being more power efficient.
The Turbo memory cache connects to a motherboard via a mini-PCIe interface.
It is designed to leverage features introduced in Windows Vista, namely ReadyBoost (a supplementation of RAM-based disk caching by dedicated files on flash drives, except on the 512 MB version) and/or ReadyDrive (a non-volatile caching solution, i.e. an implementation of a hybrid drive, as long as the main storage isn't already one);
as ReadyBoost is backed by temporary files on generic storage volumes, it is unofficially possible to destinate this space for general purpose storage.
Turbo Memory is not compatible with previous versions of Windows (with only a no-op driver that merely acknowledges the device existing for Windows 2000 and XP);
Linux support is limited to a third-party experimental MTD driver only supporting 2 GB modules.
Availability
Intel Turbo Memory was made available on May 9, 2007, on the Intel's Santa Rosa platform and their Crestline (GM965) chipsets. Intel Turbo Memory 2.0 was introduced on July 15, 2008, on Intel's Montevina platform and their Cantiga (GM47) chipsets. It is available in 1, 2, and 4GB modules. It is supported in the In |
https://en.wikipedia.org/wiki/Plane%20partition | In mathematics and especially in combinatorics, a plane partition is a two-dimensional array of nonnegative integers (with positive integer indices i and j) that is nonincreasing in both indices. This means that
and for all i and j.
Moreover, only finitely many of the may be nonzero. Plane partitions are a generalization of partitions of an integer.
A plane partition may be represented visually by the placement of a stack of unit cubes above the point (i, j) in the plane, giving a three-dimensional solid as shown in the picture. The image has matrix form
Plane partitions are also often described by the positions of the unit cubes. From this point of view, a plane partition can be defined as a finite subset of positive integer lattice points (i, j, k) in , such that if (r, s, t) lies in and if satisfies , , and , then (i, j, k) also lies in .
The sum of a plane partition is
The sum describes the number of cubes of which the plane partition consists. Much interest in plane partitions concerns the enumeration of plane partitions in various classes. The number of plane partitions with sum n is denoted by PL(n). For example, there are six plane partitions with sum 3
so PL(3) = 6.
Plane partitions may be classified by how symmetric they are. Many symmetric classes of plane partitions are enumerated by simple product formulas.
Generating function of plane partitions
The generating function for PL(n) is
.
It is sometimes referred to as the MacMahon function, as it was discovered by Percy A. MacMahon.
This formula may be viewed as the 2-dimensional analogue of Euler's product formula for the number of integer partitions of n. There is no analogous formula known for partitions in higher dimensions (i.e., for solid partitions). The asymptotics for plane partitions were first calculated by E. M. Wright. One obtains, for large , that
Evaluating numerically yields
Plane partitions in a box
Around 1896, MacMahon set up the generating function of plane pa |
https://en.wikipedia.org/wiki/Quantum%20calculus | Quantum calculus, sometimes called calculus without limits, is equivalent to traditional infinitesimal calculus without the notion of limits. It defines "q-calculus" and "h-calculus", where h ostensibly stands for Planck's constant while q stands for quantum. The two parameters are related by the formula
where is the reduced Planck constant.
Differentiation
In the q-calculus and h-calculus, differentials of functions are defined as
and
respectively. Derivatives of functions are then defined as fractions by the q-derivative
and by
In the limit, as h goes to 0, or equivalently as q goes to 1, these expressions take on the form of the derivative of classical calculus.
Integration
q-integral
A function F(x) is a q-antiderivative of f(x) if DqF(x) = f(x). The q-antiderivative (or q-integral) is denoted by and an expression for F(x) can be found from the formula
which is called the Jackson integral of f(x). For , the series converges to a function F(x) on an interval (0,A] if |f(x)xα| is bounded on the interval for some .
The q-integral is a Riemann–Stieltjes integral with respect to a step function having infinitely many points of increase at the points qj, with the jump at the point qj being qj. If we call this step function gq(t) then dgq(t) = dqt.
h-integral
A function F(x) is an h-antiderivative of f(x) if DhF(x) = f(x). The h-antiderivative (or h-integral) is denoted by . If a and b differ by an integer multiple of h then the definite integral is given by a Riemann sum of f(x) on the interval partitioned into subintervals of width h.
Example
The derivative of the function (for some positive integer ) in the classical calculus is . The corresponding expressions in q-calculus and h-calculus are
with the q-bracket
and
respectively. The expression is then the q-calculus analogue of the simple power rule for
positive integral powers. In this sense, the function is still nice in the q-calculus, but rather ugly in the h-calculus – the h-calculus a |
https://en.wikipedia.org/wiki/Canon%20T90 | The Canon T90, introduced in 1986, was the top of the line in Canon's T series of 35 mm Single-lens reflex (SLR) cameras. It is the last professional-level manual-focus camera from Canon, and the last professional camera to use the Canon FD lens mount. Although it was overtaken by the autofocus revolution and Canon's new, incompatible EOS (Electro-Optical System) after only a year in production, the T90 pioneered many concepts seen in high-end Canon cameras up to the present day, particularly the user interface, industrial design, and the high level of automation.
Due to its ruggedness, the T90 was nicknamed "the tank" by Japanese photojournalists. Many have still rated it highly even 30+ years after its introduction.
Design
Previous Canon cameras had been wholly in-house design projects. For the T90, Canon brought in German industrial designer Luigi Colani in a collaboration with Canon's own designers. The final design was composed of Colani's ideas by Kunihisa Ito of ODS Co. Ltd., incorporating Colani's distinctive "bio-form" curvaceous shapes. Canon considered Colani's contribution important enough to present him with the first production T90 body, engraved with his name. Computer-aided design techniques were introduced to Canon for the T90, as well as the use of computer controlled (CNC) milling machines to make the molding dies for the shell.
Much work went into human factors engineering to create an ergonomic user interface for the camera. The form of previous cameras was largely dictated by the required locations of mechanical controls on the body, such as the film advance lever, rewind crank, shutter speed dial, shutter release, etc. On the T90, the film transport control is no longer required, while the others are no longer mechanically linked. This gave the designers more freedom to shape the camera to make it easier to control and hold, and to place controls in a way that suited the user rather than a mechanical design.
The T90 introduced features s |
https://en.wikipedia.org/wiki/Canna%20indica | Canna indica, commonly known as Indian shot, African arrowroot, edible canna, purple arrowroot, Sierra Leone arrowroot, is a plant species in the family Cannaceae. It is native to much of South America, Central America, the West Indies, and Mexico. It is also naturalized in the southeastern United States (Florida, Texas, Louisiana, and South Carolina), and much of Europe, sub-Saharan Africa, Southeast Asia, and Oceania.
It (achira in Hispanic America, cana-da-índia in Brazil) has been a minor food crop cultivated by indigenous peoples of the Americas for thousands of years.
Description
Canna indica is a perennial growing to between , depending on the variety. It is hardy to zone 10 and is frost tender.
It forms branched rhizomes long that are divided into bulbous segments and covered in two lines by pale green or purple flaky leaves. The very large grains of starch stored there can supposedly be seen with the naked eye. The plants form an upright, unbranched stem or the overlapping leaf sheaths form a pseudo trunk.
The alternate and spiral or two-line arranged, very large, simple leaves are divided into leaf sheaths, short petioles and leaf blades. The leaf blade has a length of and a width of . The parallel leaf veins arise from the midrib (not typical of monocots). The leaves are broad, green or violet green, with petiolesshort and elliptical sheets, which can measure 30 to 60 cm long and 10 to 25 cm wide, with the base obtuse or narrowly cuneate and the apex is shortly acuminate or sharp. The surface of the rhizome is carved by transverse grooves, which mark the base of scales that cover it; from the lower part white and apex rootlets emerge, where there are numerous buds, the leaves sprout, the floral stem and the stems.
Flower
The flowers are hermaphrodite. The hermaphrodite, mostly large flowers are zygomorphic and threefold. On pedicels, they are long, red or yellow-orange, except in some cultivars, long, with the sepals being closely triangular, |
https://en.wikipedia.org/wiki/Agglutination%20%28biology%29 | Agglutination is the clumping of particles. The word agglutination comes from the Latin agglutinare (glueing to).
Agglutination is a reaction in which particles (as red blood cells or bacteria) suspended in a liquid collect into clumps usually as a response to a specific antibody.
This occurs in biology in two main examples:
The clumping of cells such as bacteria or red blood cells in the presence of an antibody or complement. The antibody or other molecule binds multiple particles and joins them, creating a large complex. This increases the efficacy of microbial elimination by phagocytosis as large clumps of bacteria can be eliminated in one pass, versus the elimination of single microbial antigens.
When people are given blood transfusions of the wrong blood group, the antibodies react with the incorrectly transfused blood group and as a result, the erythrocytes clump up and stick together causing them to agglutinate. The coalescing of small particles that are suspended in a solution; these larger masses are then (usually) precipitated.
In immunohematology
Hemagglutination
Hemagglutination is the process by which red blood cells agglutinate, meaning clump or clog. The agglutin involved in hemagglutination is called hemagglutinin. In cross-matching, donor red blood cells and the recipient's serum or plasma are incubated together. If agglutination occurs, this indicates that the donor and recipient blood types are incompatible.
When a person produces antibodies against their own red blood cells, as in cold agglutinin disease and other autoimmune conditions, the cells may agglutinate spontaneously. This is called autoagglutination and it can interfere with laboratory tests such as blood typing and the complete blood count.
Leukoagglutination
Leukoagglutination occurs when the particles involved are white blood cells.
An example is the PH-L form of phytohaemagglutinin.
In microbiology
Agglutination is commonly used as a method of identifying specific bac |
https://en.wikipedia.org/wiki/Hemagglutination | Hemagglutination, or haemagglutination, is a specific form of agglutination that involves red blood cells (RBCs). It has two common uses in the laboratory: blood typing and the quantification of virus dilutions in a haemagglutination assay.
Blood typing
Blood type can be determined by using antibodies that bind to the A or B blood group antigens in a sample of blood.
For example, if antibodies that bind the A blood group are added and agglutination occurs, the blood is either type A or type AB. To determine between type A or type AB, antibodies that bind the B group are added and if agglutination does not occur, the blood is type A. If agglutination does not occur with either antibodies that bind to type A or type B antigens, then neither antigen is present on the blood cells, which means the blood is type O.
In blood grouping, the patient's serum is tested against RBCs of known blood groups and also the patient's RBCs are tested against known serum types. In this way the patient's blood group is confirmed from both RBCs and serum. A direct Coombs test is also done on the patient's blood sample in case there are any confounding antibodies.
Viral hemagglutination assay
Many viruses attach to molecules present on the surface of RBCs. A consequence of this is that at certain concentrations, a viral suspension may bind together (agglutinate) the RBCs, thus preventing them from settling out of suspension. Since agglutination is not linked to infectivity, attenuated viruses can therefore be used in assays while an additional assay such as a plaque assay must be used to determine infectivity. By serially diluting a virus suspension into an assay tray (a series of wells of uniform volume) and adding a standard amount of blood cells, an estimation of the number of virus particles can be made. While less accurate than a plaque assay, it is cheaper and quicker (taking just 30 minutes).
This assay may be modified to include the addition of an antiserum. By using a standa |
https://en.wikipedia.org/wiki/Gaussian%20polar%20coordinates | In the theory of Lorentzian manifolds, spherically symmetric spacetimes admit a family of nested round spheres. In each of these spheres, every point can be carried to any other by an appropriate rotation about the center of symmetry.
There are several different types of coordinate chart which are adapted to this family of nested spheres, each introducing a different kind of distortion. The best known alternative is the Schwarzschild chart, which correctly represents distances within each sphere, but (in general) distorts radial distances and angles. Another popular choice is the isotropic chart, which correctly represents angles (but in general distorts both radial and transverse distances). A third choice is the Gaussian polar chart, which correctly represents radial distances, but distorts transverse distances and angles. There are other possible charts; the article on spherically symmetric spacetime describes a coordinate system with intuitively appealing features for studying infalling matter. In all cases, the nested geometric spheres are represented by coordinate spheres, so we can say that their roundness is correctly represented.
Definition
In a Gaussian polar chart (on a static spherically symmetric spacetime), the metric (aka line element) takes the form
Depending on context, it may be appropriate to regard and as undetermined functions of the radial coordinate . Alternatively, we can plug in specific functions (possibly depending on some parameters) to obtain an isotropic coordinate chart on a specific Lorentzian spacetime.
Applications
Gaussian charts are often less convenient than Schwarzschild or isotropic charts. However, they have found occasional application in the theory of static spherically symmetric perfect fluids.
See also
Static spacetime
Static spherically symmetric perfect fluids
Schwarzschild coordinates
Isotropic coordinates
Frame fields in general relativity for more about frame fields and coframe fields.
Coordina |
https://en.wikipedia.org/wiki/Chevalley%E2%80%93Warning%20theorem | In number theory, the Chevalley–Warning theorem implies that certain polynomial equations in sufficiently many variables over a finite field have solutions. It was proved by and a slightly weaker form of the theorem, known as Chevalley's theorem, was proved by . Chevalley's theorem implied Artin's and Dickson's conjecture that finite fields are quasi-algebraically closed fields .
Statement of the theorems
Let be a finite field and be a set of polynomials such that the number of variables satisfies
where is the total degree of . The theorems are statements about the solutions of the following system of polynomial equations
The Chevalley–Warning theorem states that the number of common solutions is divisible by the characteristic of . Or in other words, the cardinality of the vanishing set of is modulo .
The Chevalley theorem states that if the system has the trivial solution , that is, if the polynomials have no constant terms, then the system also has a non-trivial solution .
Chevalley's theorem is an immediate consequence of the Chevalley–Warning theorem since is at least 2.
Both theorems are best possible in the sense that, given any , the list has total degree and only the trivial solution. Alternatively, using just one polynomial, we can take f1 to be the degree n polynomial given by the norm of x1a1 + ... + xnan where the elements a form a basis of the finite field of order pn.
Warning proved another theorem, known as Warning's second theorem, which states that if the system of polynomial equations has the trivial solution, then it has at least solutions where is the size of the finite field and . Chevalley's theorem also follows directly from this.
Proof of Warning's theorem
Remark: If then
so the sum over of any polynomial in of degree less than also vanishes.
The total number of common solutions modulo of is equal to
because each term is 1 for a solution and 0 otherwise.
If the sum of the degrees of the polynomials is less |
https://en.wikipedia.org/wiki/Euphorbia%20milii | Euphorbia milii, the crown of thorns, Christ plant, or Christ's thorn, is a species of flowering plant in the spurge family Euphorbiaceae, native to Madagascar. The species name commemorates Baron Milius, once Governor of Réunion, who introduced the species to France in 1821.
The native Malagasy name for this plant is songosongo also applied to several other Euphorbia species. It is imagined that the species was introduced to the Middle East in ancient times, and legend associates it with the crown of thorns worn by Jesus. It is commonly used as an ornamental houseplant that can be grown in warmer climates. The common English name is due to the thorns and deep red bracts referring to the crown thorn Jesus had to wear during his crucifixion and his blood.
Description
It is a woody succulent subshrub or shrub growing to tall, with densely spiny stems. The straight, slender spines, up to long, help it scramble over other plants. The fleshy, green leaves are found mainly on new growth, and are up to long and broad. The flowers are small, subtended by a pair of conspicuous petal-like bracts, variably red, pink or white, up to broad. Wat Phrik in Thailand claims to be the home of the world's tallest Christ thorn plant. The plant thrives between spring and summer but produces flowers all year round.
Toxicity
The sap is moderately poisonous, and causes irritation on contact with skin or eyes. If ingested, it causes severe stomach pain, irritation of the throat and mouth, and vomiting. The poisonous ingredients have been identified as phorbol esters. It is very toxic to domesticated animals such as, horses, sheep, cats and dogs. For humans it is mildly toxic and only acts as an irritant.
Uses
Pesticide
The plant itself has proven to be an effective molluscicide and a natural alternative to pest control. The World Health Organization (WHO) has recommended the usage of Euphorbia milii in aiding snail control. Especially in endemic countries. Schistosomiasis is an |
https://en.wikipedia.org/wiki/Cognitive%20robotics | Cognitive Robotics or Cognitive Technology is a subfield of robotics concerned with endowing a robot with intelligent behavior by providing it with a processing architecture that will allow it to learn and reason about how to behave in response to complex goals in a complex world. Cognitive robotics may be considered the engineering branch of embodied cognitive science and embodied embedded cognition, consisting of Robotic Process Automation, Artificial Intelligence, Machine Learning, Deep Learning, Optical Character Recognition, Image Processing, Process Mining, Analytics, Software Development and System Integration.
Core issues
While traditional cognitive modeling approaches have assumed symbolic coding schemes as a means for depicting the world, translating the world into these kinds of symbolic representations has proven to be problematic if not untenable. Perception and action and the notion of symbolic representation are therefore core issues to be addressed in cognitive robotics.
Starting point
Cognitive robotics views human or animal cognition as a starting point for the development of robotic information processing, as opposed to more traditional Artificial Intelligence techniques. Target robotic cognitive capabilities include perception processing, attention allocation, anticipation, planning, complex motor coordination, reasoning about other agents and perhaps even about their own mental states. Robotic cognition embodies the behavior of intelligent agents in the physical world (or a virtual world, in the case of simulated cognitive robotics). Ultimately the robot must be able to act in the real world.
Learning techniques
Motor Babble
A preliminary robot learning technique called motor babbling involves correlating pseudo-random complex motor movements by the robot with resulting visual and/or auditory feedback such that the robot may begin to expect a pattern of sensory feedback given a pattern of motor output. Desired sensory feedback may then b |
https://en.wikipedia.org/wiki/Golden%20Telecom | Golden Telecom is an internet services provider in Russia and the Commonwealth of Independent States (CIS). It was acquired by VimpelCom in 2007.
History
Founded in 1996 by the global corporation Global Telesystems ("GTS"). NYSE-listed Global TeleSystems ("GTS") was the owner of EBONE one of Europe's leading broadband optical and IP network service providers (a Tier 1 network). GTS had its IPO on the NASDAQ in 1998. In 2000, a new management including Robert A. Schriesheim as CFO, was brought in to help restructure and refocus the company. GTS was a pan-European communications services provider, backed by Alan B. Slifka and affiliates of George Soros and Soros Private Equity, with revenues of over $1 billion and operations in 20 countries in Europe. In October 1999 GTS did an IPO of on the NASDAQ of, Golden Telecom, which held communications assets in Russia, with GTS retaining a 65% interest. GTS was essentially a portfolio of communications assets in Western and Eastern Europe which went through an IPO in 1998 and subsequently experienced challenges with an over-levered balance sheet as Europe went through deregulation and from the overall fall-out of the dot.com boom and bust which impacted its customer base. In 2001, to facilitate the sale of GTS, Mr. Schriesheim helped lead it through a pre-arranged filing under Chapter 11 of the United States Bankruptcy Code (U.S.B.C.) and, in prearranged proceedings, a petition for surseance (moratorium), offering a composition, in the Netherlands to restructure its debt, in excess of $2 billion. All such proceedings were approved, confirmed and completed by March 31, 2002, as part of the sale of the company. David A. Stewart served as Senior Vice President, chief financial officer and Treasurer at that time and left Golden Telecom in 2004.
Golden Telecom was acquired by VimpelCom in 2007.
List of acquisitions by Golden Telecom
July 2000 — IT Infoart Stars
July 2000 — search engine aport.ru
April 2001 – internet service |
https://en.wikipedia.org/wiki/Lateral%20epicondyle%20of%20the%20humerus | The lateral epicondyle of the humerus is a large, tuberculated eminence, curved a little forward, and giving attachment to the radial collateral ligament of the elbow joint, and to a tendon common to the origin of the supinator and some of the extensor muscles. Specifically, these extensor muscles include the anconeus muscle, the supinator, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris. In birds, where the arm is somewhat rotated compared to other tetrapods, it is termed dorsal epicondyle of the humerus. In comparative anatomy, the term ectepicondyle is sometimes used.
A common injury associated with the lateral epicondyle of the humerus is lateral epicondylitis also known as tennis elbow. Repetitive overuse of the forearm, as seen in tennis or other sports, can result in inflammation of "the tendons that join the forearm muscles on the outside of the elbow. The forearm muscles and tendons become damaged from overuse. This leads to pain and tenderness on the outside of the elbow."
See also
Medial epicondyle of the humerus
Common extensor tendon
Tennis elbow (lateral epicondylitis)
Additional images |
https://en.wikipedia.org/wiki/Run-time%20algorithm%20specialization | In computer science, run-time algorithm specialization is a methodology for creating efficient algorithms for costly computation tasks of certain kinds. The methodology originates in the field of automated theorem proving and, more specifically, in the Vampire theorem prover project.
The idea is inspired by the use of partial evaluation in optimising program translation.
Many core operations in theorem provers exhibit the following pattern.
Suppose that we need to execute some algorithm in a situation where a value of is fixed for potentially many different values of . In order to do this efficiently, we can try to find a specialization of for every fixed , i.e., such an algorithm , that executing is equivalent to executing .
The specialized algorithm may be more efficient than the generic one, since it can exploit some particular properties of the fixed value . Typically, can avoid some operations that would have to perform, if they are known to be redundant for this particular parameter .
In particular, we can often identify some tests that are true or false for , unroll loops and recursion, etc.
Difference from partial evaluation
The key difference between run-time specialization and partial evaluation is that the values of on which is specialised are not known statically, so the specialization takes place at run-time.
There is also an important technical difference. Partial evaluation is applied to algorithms explicitly represented as codes in some programming language. At run-time, we do not need any concrete representation of . We only have to imagine when we program the specialization procedure.
All we need is a concrete representation of the specialized version . This also means that we cannot use any universal methods for specializing algorithms, which is usually the case with partial evaluation. Instead, we have to program a specialization procedure for every particular algorithm . An important advantage of doing so is that we can use some |
https://en.wikipedia.org/wiki/Chiral%20column%20chromatography | Chiral column chromatography is a variant of column chromatography that is employed for the separation of chiral compounds, i.e. enantiomers, in mixtures such as racemates or related compounds. The chiral stationary phase (CSP) is made of a support, usually silica based, on which a chiral reagent or a macromolecule with numerous chiral centers is bonded or immobilized.
The chiral stationary phase can be prepared by attaching a chiral compound to the surface of an achiral support such as silica gel. For example, one class of the most commonly used chiral stationary phases both in liquid chromatography and supercritical fluid chromatography is based on oligosaccharides such as Amylose Cellulose or Cyclodextrin (in particular with β-cyclodextrin, a seven sugar ring molecule) immobilized on silica gel.
The principle can be also applied to the fabrication of Monolithic HPLC columns or Gas Chromatography columns. or Supercritical Fluid Chromatography columns.
The
Principle of Chiral Column Chromatography
The chiral stationary phase, CSP, can interact differently with two enantiomers, by a process known as chiral recognition. Chiral recognition depends on various interactions such as hydrogen bonding, π-π interaction, dipole stacking, inclusion complexation, steric, hydrophobic and electrostatic interaction, charge-transfer interactions, ionic interactions etc, between the analyte and the CSP, to form in-situ transient-diastereomeric complexes.
Most of the types of stationary phases can be classified as Pirkle type (Brush type), Protein-based, Cyclodextrins based, Polymer-based carbohydrates (polysaccharide-based CSPs), Macrocyclic antibiotic, Chiral crown ethers, imprinted polymers, etc.
Brush type columns (Pirkle Type)
The brush type, or Pirkle type chiral stationary phases are also called π-π Donnor-Acceptor columns. According to some theoretical models separation on these CSPs is based on a three-point attachment between the solute and the bonded chiral ligan |
https://en.wikipedia.org/wiki/Noetherian%20topological%20space | In mathematics, a Noetherian topological space, named for Emmy Noether, is a topological space in which closed subsets satisfy the descending chain condition. Equivalently, we could say that the open subsets satisfy the ascending chain condition, since they are the complements of the closed subsets. The Noetherian property of a topological space can also be seen as a strong compactness condition, namely that every open subset of such a space is compact, and in fact it is equivalent to the seemingly stronger statement that every subset is compact.
Definition
A topological space is called Noetherian if it satisfies the descending chain condition for closed subsets: for any sequence
of closed subsets of , there is an integer such that
Properties
A topological space is Noetherian if and only if every subspace of is compact (i.e., is hereditarily compact), and if and only if every open subset of is compact.
Every subspace of a Noetherian space is Noetherian.
The continuous image of a Noetherian space is Noetherian.
A finite union of Noetherian subspaces of a topological space is Noetherian.
Every Hausdorff Noetherian space is finite with the discrete topology.
Proof: Every subset of X is compact in a Hausdorff space, hence closed. So X has the discrete topology, and being compact, it must be finite.
Every Noetherian space X has a finite number of irreducible components. If the irreducible components are , then , and none of the components is contained in the union of the other components.
From algebraic geometry
Many examples of Noetherian topological spaces come from algebraic geometry, where for the Zariski topology an irreducible set has the intuitive property that any closed proper subset has smaller dimension. Since dimension can only 'jump down' a finite number of times, and algebraic sets are made up of finite unions of irreducible sets, descending chains of Zariski closed sets must eventually be constant.
A more algebraic way to see |
https://en.wikipedia.org/wiki/Chief%20cell | In human anatomy, there are three types of chief cells, the gastric chief cell, the parathyroid chief cell, and the type 1 chief cells found in the carotid body.
Cell types
The gastric chief cell (also known as a zymogenic cell or peptic cell) is a cell in the stomach that releases pepsinogen and chymosin. Pepsinogen is activated into the digestive enzyme pepsin when it comes in contact with hydrochloric acid produced by gastric parietal cells. This type of cell also secretes gastric lipase enzymes, which help digest triglycerides into free fatty acids and di- and mono-glycerides. There is also evidence that the gastric chief cell secretes leptin in response to the presence of food in the stomach. Leptin has been found in the pepsinogen granules of chief cells.
Gastric pit cells are replaced every 2–4 days. This high rate of turnover is a protective mechanism designed to protect the epithelial lining of the stomach from both the proteolytic action of pepsin and the acid produced by parietal cells. Gastric chief cells are much longer lived and are believed to differentiate from stem cells located higher in the gastric unit in the isthmus. These stem cells differentiate into mucous neck cells in the isthmus and transition into chief cells as they migrate towards the base. Since the mucus neck cells do not divide as it becomes a chief cell this process is known as transdifferentiation. The gene Mist1 has been shown to regulate mucus neck cell to chief cell transdifferentiation and plays a role in the normal development of the chief cell organelles and structures.
The parathyroid chief cell is the primary cell of the parathyroid gland. It produces and secretes parathyroid hormone in response to low calcium levels. PTH plays an important role in regulating blood calcium levels by raising the amount of calcium in the blood. Parathyroid tissue seems to have a low turn-over rate.
Histology
Gastric chief cells are epithelial cells which are found within the gastric uni |
https://en.wikipedia.org/wiki/Amaranthus%20albus | Amaranthus albus is an annual species of flowering plant. It is native to the tropical Americas but a widespread introduced species in other places, including Europe, Africa and Australia.
Common names include common tumbleweed, tumble pigweed, tumbleweed, prostrate pigweed, pigweed amaranth, white amaranth and white pigweed.
Amaranthus albus is an annual herb up to 50 cm (20 inches) tall, forming many branches. Larger specimens turn into tumbleweeds when they die and dry out. The plant creates small, greenish flowers in clumps in the axils of the leaves. Male and female flowers are mixed together in the same clump.
In Cambodia, the leaves of the plant (which is known as phti sâ, Khmer language) is used as pig-feed, and are sometimes cooked and eaten by people. |
https://en.wikipedia.org/wiki/Trusted%20Platform%20Module | Trusted Platform Module (TPM, also known as ISO/IEC 11889) is an international standard for a secure cryptoprocessor, a dedicated microcontroller designed to secure hardware through integrated cryptographic keys. The term can also refer to a chip conforming to the standard.
One of Windows 11's system requirements is TPM 2.0. Microsoft has stated that this is to help increase security against firmware attacks.
History
Trusted Platform Module (TPM) was conceived by a computer industry consortium called Trusted Computing Group (TCG). It evolved into TPM Main Specification Version 1.2 which was standardized by International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC) in 2009 as ISO/IEC 11889:2009. TPM Main Specification Version 1.2 was finalized on March 3, 2011, completing its revision.
On April 9, 2014, the Trusted Computing Group announced a major upgrade to their specification entitled TPM Library Specification 2.0. The group continues work on the standard incorporating errata, algorithmic additions and new commands, with its most recent edition published as 2.0 in November 2019. This version became ISO/IEC 11889:2015.
When a new revision is released it is divided into multiple parts by the Trusted Computing Group. Each part consists of a document that makes up the whole of the new TPM specification.
Part 1 – Architecture (renamed from Design Principles)
Part 2 – Structures of the TPM
Part 3 – Commands
Part 4 – Supporting Routines (added in TPM 2.0)
Overview
Trusted Platform Module provides
A hardware random number generator
Facilities for the secure generation of cryptographic keys for limited uses.
Remote attestation: Creates a nearly unforgeable hash key summary of the hardware and software configuration. One could use the hash to verify that the hardware and software have not been changed. The software in charge of hashing the setup determines the extent of the summary.
Binding: Encrypts data using t |
https://en.wikipedia.org/wiki/Canterbury%20corpus | The Canterbury corpus is a collection of files intended for use as a benchmark for testing lossless data compression algorithms. It was created in 1997 at the University of Canterbury, New Zealand and designed to replace the Calgary corpus. The files were selected based on their ability to provide representative performance results.
Contents
In its most commonly used form, the corpus consists of 11 files, selected as "average" documents from 11 classes of documents, totaling 2,810,784 bytes as follows.
The University of Canterbury also offers the following corpora. Additional files may be added, so results should be only reported for individual files.
The Artificial Corpus, a set of files with highly "artificial" data designed to evoke pathological or worst-case behavior. Last updated 2000 (tar timestamp).
The Large Corpus, a set of large (megabyte-size) files. Contains an E. coli genome, a King James bible, and the CIA world fact book. Last updated 1997 (tar timestamp).
The Miscellaneous Corpus. Contains one million digits of pi. Last updated 2000 (tar timestamp).
See also
Data compression |
https://en.wikipedia.org/wiki/Image%20scaling | In computer graphics and digital imaging, image scaling refers to the resizing of a digital image. In video technology, the magnification of digital material is known as upscaling or resolution enhancement.
When scaling a vector graphic image, the graphic primitives that make up the image can be scaled using geometric transformations, with no loss of image quality. When scaling a raster graphics image, a new image with a higher or lower number of pixels must be generated. In the case of decreasing the pixel number (scaling down) this usually results in a visible quality loss. From the standpoint of digital signal processing, the scaling of raster graphics is a two-dimensional example of sample-rate conversion, the conversion of a discrete signal from a sampling rate (in this case the local sampling rate) to another.
Mathematical
Image scaling can be interpreted as a form of image resampling or image reconstruction from the view of the Nyquist sampling theorem. According to the theorem, downsampling to a smaller image from a higher-resolution original can only be carried out after applying a suitable 2D anti-aliasing filter to prevent aliasing artifacts. The image is reduced to the information that can be carried by the smaller image.
In the case of up sampling, a reconstruction filter takes the place of the anti-aliasing filter.
A more sophisticated approach to upscaling treats the problem as an inverse problem, solving the question of generating a plausible image, which, when scaled down, would look like the input image. A variety of techniques have been applied for this, including optimization techniques with regularization terms and the use of machine learning from examples.
Algorithms
An image size can be changed in several ways.
Nearest-neighbor interpolation
One of the simpler ways of increasing image size is nearest-neighbor interpolation, replacing every pixel with the nearest pixel in the output; for upscaling this means multiple pixels of the sam |
https://en.wikipedia.org/wiki/Concordance%20%28genetics%29 | In genetics, concordance is the probability that a pair of individuals will both have a certain characteristic (phenotypic trait) given that one of the pair has the characteristic. Concordance can be measured with concordance rates, reflecting the odds of one person having the trait if the other does. Important clinical examples include the chance of offspring having a certain disease if the mother has it, if the father has it, or if both parents have it. Concordance among siblings is similarly of interest: what are the odds of a subsequent offspring having the disease if an older child does? In research, concordance is often discussed in the context of both members of a pair of twins. Twins are concordant when both have or both lack a given trait. The ideal example of concordance is that of identical twins, because the genome is the same, an equivalence that helps in discovering causation via deconfounding, regarding genetic effects versus epigenetic and environmental effects (nature versus nurture).
In contrast, discordance occurs when a similar trait is not shared by the persons. Studies of twins have shown that genetic traits of monozygotic twins are fully concordant, whereas in dizygotic twins, half of genetic traits are concordant, while the other half are discordant. Discordant rates that are higher than concordant rates express the influence of the environment on twin traits.
Studies
A twin study compares the concordance rate of identical twins to that of fraternal twins. This can help suggest whether a disease or a certain trait has a genetic cause. Controversial uses of twin data have looked at concordance rates for homosexuality and intelligence. Other studies have involved looking at the genetic and environmental factors that can lead to increased LDL in women twins.
Because identical twins are genetically virtually identical, it follows that a genetic pattern carried by one would very likely also be carried by the other. If a characteristic ident |
https://en.wikipedia.org/wiki/Basal%20cell | Basal cell may refer to:
the epidermal cell in the stratum basale
the airway basal cell, an epithelial cell in the respiratory epithelium |
https://en.wikipedia.org/wiki/Nanophase%20material | Nanophase materials are materials that have grain sizes under 100 nanometres. They have different mechanical and optical properties compared to the large grained materials of the same chemical composition.
Transparency and different transparent colours can be achieved with nanophase materials by varying the grain size.
Nanophase materials
Nanophase metals usually are many times harder but more brittle than regular metals.
nanophase copper is a superhard material
nanophase aluminum
nanophase iron is iron with a grain size in the nanometer range. Nanocrystalline iron has a tensile strength of around 6 GPA, twice that of the best maraging steels.
Nanophase ceramics usually are more ductile and less brittle than regular ceramics.
Footnotes
External links
Creating Nanophase Materials. Scientific American (subscription required)
Nanophase Materials, Michigan Tech
Research on Nanophase Materials, Louisiana State University
Materials |
https://en.wikipedia.org/wiki/Thermophotovoltaic%20energy%20conversion | Thermophotovoltaic (TPV) energy conversion is a direct conversion process from heat to electricity via photons. A basic thermophotovoltaic system consists of a hot object emitting thermal radiation and a photovoltaic cell similar to a solar cell but tuned to the spectrum being admitted from the hot object.
As TPV systems generally work at lower temperatures than solar cells, their efficiencies tend to be low. Offsetting this through the use of multi-junction cells based on non-silicon materials is common, but generally very expensive. This currently limits TPV to niche roles like spacecraft power and waste heat collection from larger systems like steam turbines.
General concept
PV
Typical photovoltaics work by creating a p–n junction near the front surface of a thin semiconductor material. When photons above the bandgap energy of the material hit atoms within the bulk lower layer, below the junction, an electron is photoexcited and becomes free of its atom. The junction creates an electric field that accelerates the electron forward within the cell until it passes the junction and is free to move to the thin electrodes patterned on the surface. Connecting a wire from the front to the rear allows the electrons to flow back into the bulk and complete the circuit.
Photons with less energy than the bandgap do not eject electrons. Photons with energy above the bandgap will eject higher-energy electrons which tend to thermalize within the material and lose their extra energy as heat. If the cell's bandgap is raised, the electrons that are emitted will have higher energy when they reach the junction and thus result in a higher voltage, but this will reduce the number of electrons emitted as more photons will be below the bandgap energy and thus generate a lower current. As electrical power is the product of voltage and current, there is a sweet spot where the total output is maximized.
Terrestrial solar radiation is typically characterized by a standard known as Air M |
https://en.wikipedia.org/wiki/Horizontal%20blanking%20interval | Horizontal blanking interval refers to a part of the process of displaying images on a computer monitor or television screen via raster scanning. CRT screens display images by moving beams of electrons very quickly across the screen. Once the beam of the monitor has reached the edge of the screen, it is switched off, and the deflection circuit voltages (or currents) are returned to the values they had for the other edge of the screen; this would have the effect of retracing the screen in the opposite direction, so the beam is turned off during this time. This part of the line display process is the Horizontal Blank.
In detail, the Horizontal blanking interval consists of:
front porch – blank while still moving right, past the end of the scanline,
sync pulse – blank while rapidly moving left; in terms of amplitude, "blacker than black".
back porch – blank while moving right again, before the start of the next scanline. Colorburst occurs during the back porch, and unblanking happens at the end of the back porch.
In the NTSC television standard, horizontal blanking occupies out of every scan line (17.2%). In PAL, it occupies out of every scan line (18.8%).
Some modern monitors and video cards support reduced blanking, standardized with Coordinated Video Timings.
In the PAL television standard, the blanking level corresponds to the black level, whilst other standards, most notably NTSC, set the black level slightly above the blanking level on a pedestal.
HBlank effects
Some graphics systems can count horizontal blanks and change how the display is generated during this blank time in the signal; this is called a raster effect, of which an example is raster bars.
In video games, the horizontal blanking interval was used to create some notable effects. Some methods of parallax scrolling use a raster effect to simulate depth in consoles that do not natively support multiple background layers or do not support enough background layers to achieve the desired |
https://en.wikipedia.org/wiki/Constraint-based%20Routing%20Label%20Distribution%20Protocol | Constraint-based Routing Label Distribution Protocol (CR-LDP) is a control protocol used in some computer networks.
As of February 2003, the IETF MPLS working group deprecated CR-LDP and decided to focus purely on RSVP-TE.
It is an extension of the Label Distribution Protocol (LDP), one of the protocols in the Multiprotocol Label Switching architecture. CR-LDP contains extensions for LDP to extend its capabilities such as setup paths beyond what is available for the routing protocol. For instance, a label-switched path can be set up based on explicit route constraints, quality of service constraints, and other constraints. Constraint-based routing (CR) is a mechanism used to meet traffic engineering requirements. These requirements are met by extending LDP for support of constraint-based routed label-switched paths (CR-LSPs). Other uses for CR-LSPs include MPLS-based virtual private networks.
CR-LDP is almost same as basic LDP, in packet structure, but it contains some extra TLVs which basically set up the constraint-based LSP. |
https://en.wikipedia.org/wiki/Scalar%20processor | Scalar processors are a class of computer processors that process only one data item at a time. Typical data items include integers and floating point numbers.
Classification
A scalar processor is classified as a single instruction, single data (SISD) processor in Flynn's taxonomy. The Intel 486 is an example of a scalar processor. It is to be contrasted with a vector processor where a single instruction operates simultaneously on multiple data items (and thus is referred to as a single instruction, multiple data (SIMD) processor). The difference is analogous to the difference between scalar and vector arithmetic.
The term scalar in computing dates to the 1970 and 1980s when vector processors were first introduced. It was originally used to distinguish the older designs from the new vector processors.
Superscalar processor
A superscalar processor (such as the Intel P5) may execute more than one instruction during a clock cycle by simultaneously dispatching multiple instructions to redundant functional units on the processor. Each functional unit is not a separate CPU core but an execution resource within a single CPU such as an arithmetic logic unit, a bit shifter, or a multiplier. The Cortex-M7, like many consumer CPUs today, is a superscalar processor.
Scalar data type
A scalar data type, or just scalar, is any non-composite value.
Generally, all basic primitive data types are considered scalar:
The boolean data type (bool)
Numeric types (int, the floating point types float and double)
Character types (char and string)
See also
Instruction pipeline
Parallel computing |
https://en.wikipedia.org/wiki/Eucalyptol | Eucalyptol (also called cineole) is a monoterpenoid colorless liquid, and a bicyclic ether. It has a fresh camphor-like odor and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up about 70–90% of eucalyptus oil. Eucalyptol forms crystalline adducts with hydrohalic acids, o-cresol, resorcinol, and phosphoric acid. Formation of these adducts is useful for purification.
In 1870, F. S. Cloez identified and ascribed the name "eucalyptol" to the dominant portion of Eucalyptus globulus oil.
Uses
Because of its pleasant, spicy aroma and taste, eucalyptol is used in flavorings, fragrances, and cosmetics. Cineole-based eucalyptus oil is used as a flavoring at low levels (0.002%) in various products, including baked goods, confectionery, meat products, and beverages. In a 1994 report released by five top cigarette companies, eucalyptol was listed as one of the 599 additives to cigarettes. It is claimed to be added to improve the flavor.
Eucalyptol is an ingredient in commercial mouthwashes, and has been used in traditional medicine as a cough suppressant.
Other
Eucalyptol exhibits insecticidal and insect repellent properties.
In contrast, eucalyptol is one of many compounds that are attractive to males of various species of orchid bees, which gather the chemical to synthesize pheromones; it is commonly used as bait to attract and collect these bees for study. One such study with Euglossa imperialis, a nonsocial orchid bee species, has shown that the presence of cineole (also eucalyptol) elevates territorial behavior and specifically attracts the male bees. It was even observed that these males would periodically leave their territories to forage for chemicals such as cineole, thought to be important for attracting and mating with females, to synthesize pheromones.
Toxicology
Eucalyptol has a toxicity (LD50) of 2.48 grams per kg (rat). Ingestion in significant quantities is likely to cause headache and gastric distre |
https://en.wikipedia.org/wiki/Kuramoto%20model | The Kuramoto model (or Kuramoto–Daido model), first proposed by , is a mathematical model used in describing synchronization. More specifically, it is a model for the behavior of a large set of coupled oscillators. Its formulation was motivated by the behavior of systems of chemical and biological oscillators, and it has found widespread applications in areas such as neuroscience and oscillating flame dynamics. Kuramoto was quite surprised when the behavior of some physical systems, namely coupled arrays of Josephson junctions, followed his model.
The model makes several assumptions, including that there is weak coupling, that the oscillators are identical or nearly identical, and that interactions depend sinusoidally on the phase difference between each pair of objects.
Definition
In the most popular version of the Kuramoto model, each of the oscillators is considered to have its own intrinsic natural frequency , and each is coupled equally to all other oscillators. Surprisingly, this fully nonlinear model can be solved exactly in the limit of infinite oscillators, N→ ∞; alternatively, using self-consistency arguments one may obtain steady-state solutions of the order parameter.
The most popular form of the model has the following governing equations:
,
where the system is composed of N limit-cycle oscillators, with phases and coupling constant K.
Noise can be added to the system. In that case, the original equation is altered to
,
where is the fluctuation and a function of time. If we consider the noise to be white noise, then
,
with denoting the strength of noise.
Transformation
The transformation that allows this model to be solved exactly (at least in the N → ∞ limit) is as follows:
Define the "order" parameters r and ψ as
.
Here r represents the phase-coherence of the population of oscillators and ψ indicates the average phase. Multiplying this equation with and only considering the imaginary part gives
.
Thus the oscillators' equations are no |
https://en.wikipedia.org/wiki/Functional%20group%20%28ecology%29 | A functional group is merely a set of species, or collection of organisms, that share alike characteristics within a community. Ideally, the lifeforms would perform equivalent tasks based on domain forces, rather than a common ancestor or evolutionary relationship. This could potentially lead to analogous structures that overrule the possibility of homology. More specifically, these beings produce resembling effects to external factors of an inhabiting system. Due to the fact that a majority of these creatures share an ecological niche, it is practical to assume they require similar structures in order to achieve the greatest amount of fitness. This refers to such as the ability to successfully reproduce to create offspring, and furthermore sustain life by avoiding alike predators and sharing meals.
Scientific investigation
Rather than the idea of this concept based upon a set of theories, functional groups are directly observed and determined by research specialists. It is important that this information is witnessed first-hand in order to state as usable evidence. Behavior and overall contribution to others are common key points to look for. Individuals use the corresponding perceived traits to further link genetic profiles to one another. Although, the life-forms themselves are different, variables based upon overall function and performance are interchangeable. These groups share an indistinguishable part within their energy flow, providing a key position within food chains and relationships within environment(s).
What is an ecosystem and why is that important? An ecosystem is the biological organization that defines and expands on various environment factors- abiotic and biotic, that relate to simultaneous interaction. Whether it be a producer or relative consumer, each and every piece of life maintains a critical position in the ongoing survival rates of its own surroundings. As it pertains, a functional groups shares a very specific role within any given e |
https://en.wikipedia.org/wiki/Paris%20green | Paris green (copper(II) acetate triarsenite or copper(II) acetoarsenite) is an arsenic-based organic pigment. As a green pigment it is also known as Schweinfurt green, emerald or Vienna green. It is a highly toxic emerald-green crystalline powder that has been used as a rodenticide and insecticide, and also as a pigment. It was manufactured in 1814 to be a pigment to make a vibrant green paint, and was used by many notable painters in the 19th century. The color of Paris green is said to range from a pale blue green when very finely ground, to a deeper green when coarsely ground. Due to the presence of arsenic, the pigment is extremely toxic and in paintings, the color can degrade quickly.
Preparation and structure
Paris green may be prepared by combining copper(II) acetate and arsenic trioxide. The structure was confirmed by X-ray crystallography.
History
In 1814, Paris green was invented by paint manufacturers, Wilhelm Sattler and Friedrich Russ, in Schweinfurt, Germany for the Wilhelm Dye and White Lead Company. They were attempting to produce a more stable pigment than Scheele's green, seeking to make a green that was less susceptible to darkening around sulfides. In 1822, the recipe for emerald green was published by Justus von Liebig and André Braconnot. In 1867, the pigment was named Paris green and was officially recognized as the first chemical insecticide in the world. Because of its arsenic content, the pigment was dangerous and toxic to manufacture, often resulting in factory poisonings. At the time, emerald green was praised as a more durable and vibrant substitute for Scheele’s green, even though it would later prove to degrade quickly and react with other manufactured paints.
Pigment
In paintings, the pigment produces a rich, dark green with an undertone of blue. In comparison, Scheele's green is more yellow, and therefore, more lime-green. Paris green became popular in the 19th century because of its brilliant color. It was also called Emerald |
https://en.wikipedia.org/wiki/Plesiomorphy%20and%20symplesiomorphy | In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades.
Plesiomorphy, symplesiomorphy, apomorphy, and synapomorphy, all mean a trait shared between species because they share an ancestral species.
Apomorphic and synapomorphic characteristics convey much information about evolutionary clades and can be used to define taxa. However, plesiomorphic and symplesiomorphic characteristics cannot.
The term symplesiomorphy was introduced in 1950 by German entomologist Willi Hennig.
Examples
A backbone is a plesiomorphic trait shared by birds and mammals, and does not help in placing an animal in one or the other of these two clades. Birds and mammals share this trait because both clades are descended from the same far distant ancestor. Other clades, e.g. snakes, lizards, turtles, fish, frogs, all have backbones and none are either birds nor mammals.
Being a hexapod is plesiomorphic trait shared by ants and beetles, and does not help in placing an animal in one or the other of these two clades. Ants and beetles share this trait because both clades are descended from the same far distant ancestor. Other clades, e.g. bugs, flies, bees, aphids, and many more clades, all are hexapods and none are either ants nor beetles.
Elytra are a synapomorphy for placing any living species into the beetle clade, Elytra are plesiomorphic between clades of beetles, e.g. they do not distinguish the dung beetles from the horned beetles. The metapleural gland is a synapomorphy for placing any living species into the ant clade.
Feathers are a synapomorphy for placing any living species into the bird clade, hair is a synapomorphy for placing any living species into the mammal clade. Note that some mammal species have lost their hair, so the absence of hair does not exclude a species from being a mammal. Another mammalian synapomorphy is milk. All mam |
https://en.wikipedia.org/wiki/Declaration%20of%20Helsinki | The Declaration of Helsinki (DoH, ), is a set of ethical principles regarding human experimentation developed originally in 1964 for the medical community by the World Medical Association (WMA). It is widely regarded as the cornerstone document on human research ethics.
It is not a legally binding instrument under the international law, but instead draws its authority from the degree to which it has been codified in, or influenced, national or regional legislation and regulations. Its role was described by a Brazilian forum in 2000 in these words: "Even though the Declaration of Helsinki is the responsibility of the World Medical Association, the document should be considered the property of all humanity."
Principles
The Declaration is morally binding on physicians, and that obligation overrides any national or local laws or regulations, if the Declaration provides for a higher standard of protection of humans than the latter. Investigators still have to abide by local legislation but will be held to the higher standard.
Basic principles
The fundamental principle is respect for the individual (Article 8), his or her right to self-determination and the right to make informed decisions (Articles 20, 21 and 22) regarding participation in research, both initially and during the course of the research. The investigator's duty is solely to the patient (Articles 2, 3 and 10) or volunteer (Articles 16, 18), and while there is always a need for research (Article 6), the participant's welfare must always take precedence over the interests of science and society (Article 5), and ethical considerations must always take precedence over laws and regulations (Article 9).
The recognition of the increased vulnerability of individuals and groups calls for special vigilance (Article 8). It is recognized that when the research participant is incompetent, physically or mentally incapable of giving consent, or is a minor (Articles 23, 24), then allowance should be considered for su |
https://en.wikipedia.org/wiki/Methylparaben | Methylparaben (methyl paraben) one of the parabens, is a preservative with the chemical formula CH3(C6H4(OH)COO). It is the methyl ester of p-hydroxybenzoic acid.
Natural occurrences
Methylparaben serves as a pheromone for a variety of insects and is a component of queen mandibular pheromone.
It is a pheromone in wolves produced during estrus associated with the behavior of alpha male wolves preventing other males from mounting females in heat.
Uses
Methylparaben is an anti-fungal agent often used in a variety of cosmetics and personal-care products. It is also used as a food preservative and has the E number E218.
Methylparaben is commonly used as a fungicide in Drosophila food media at 0.1%. To Drosophila, methylparaben is toxic at higher concentrations, has an estrogenic effect (mimicking estrogen in rats and having anti-androgenic activity), and slows the growth rate in the larval and pupal stages at 0.2%.
Safety
There is controversy about whether methylparaben or propylparabens are harmful at concentrations typically used in body care or cosmetics. Methylparaben and propylparaben are considered generally recognized as safe (GRAS) by the USFDA for food and cosmetic antibacterial preservation. Methylparaben is readily metabolized by common soil bacteria, making it completely biodegradable.
Methylparaben is readily absorbed from the gastrointestinal tract or through the skin. It is hydrolyzed to p-hydroxybenzoic acid and rapidly excreted in urine without accumulating in the body. Acute toxicity studies have shown that methylparaben is practically non-toxic by both oral and parenteral administration in animals. In a population with normal skin, methylparaben is practically non-irritating and non-sensitizing; however, allergic reactions to ingested parabens have been reported. A 2008 study found no competitive binding for human estrogen and androgen receptors for methylparaben, but varying levels of competitive binding were seen with butyl- and isobutyl- |
https://en.wikipedia.org/wiki/Butylparaben | Butylparaben, or butyl p-hydroxybenzoate, is an organic compound with the formula . It is a white solid that is soluble in organic solvents. It has proven to be a highly successful antimicrobial preservative in cosmetics. It is also used in medication suspensions, and as a flavoring additive in food.
Natural occurrence
Members of the paraben family are found in fruit and vegetable products, such as barley, flax seed, and grapes. Butylparaben has also been found to be produced in some microorganisms including Microbulbifer .
Preparation
Butylparaben is prepared by the esterification of 4-hydroxybenzoic acid with 1-butanol in the presence of an acid catalyst such as sulfuric acid. It is produced industrially.
Uses and reactions
Butylparaben is one of the most common bactericidal/fungicidal additives in cosmetics. It has been used in cosmetic products since the 1940s and in pharmaceutical products since 1924. The popularity of butylparaben in these products is due to its low toxicity in humans and its effective antimicrobial properties, in particular those against mold and yeast. It is now found in more than 20,000 cosmetic products including eye shadow, facial moisturizer/treatment, anti-aging cream, foundation, and sunscreen. It is also used as low-ionic strength solutions as a preservative in some foods and drugs. In most cosmetics paraben is used at low levels, ranging from 0.01 to 0.3%. Butylparaben is used in low concentrations in liquid and solid medication suspensions, such as Tylenol (acetaminophen) and ibuprofen.
Mechanism of action
The exact mechanism of how parabens work is unknown but they are proposed to act by inhibiting DNA and RNA synthesis, and enzymes like ATPase and phosphotransferase in some bacterial species. It has also been suggested that they interfere with membrane transport processes by disrupting the lipid bilayer and possibly causing the leakage of intracellular constituents.
Regulation and controversy
Butylparaben has not esca |
https://en.wikipedia.org/wiki/Polyvinylpolypyrrolidone | Polyvinylpolypyrrolidone (polyvinyl polypyrrolidone, PVPP, crospovidone, crospolividone, or E1202) is a highly cross-linked modification of polyvinylpyrrolidone (PVP).
The cross-linked form of PVP is used as a disintegrant (see also excipients) in pharmaceutical tablets. PVPP is a highly cross-linked version of PVP, making it insoluble in water, though it still absorbs water and swells very rapidly generating a swelling force. This property makes it useful as a disintegrant in tablets.
PVPP can be used as a drug, taken as a tablet or suspension to absorb compounds (so-called endotoxins) that cause diarrhea. (Cf. bone char, charcoal.)
It is also used as a fining to extract impurities (via agglomeration followed by filtration). It is used in winemaking. Using the same principle it is used to remove polyphenols in beer production and thus clear beers with stable foam are produced. One such commercial product is called Polyclar. PVPP forms bonds similar to peptidic bonds in protein (especially, like proline residues) and that is why it can precipitate tannins the same way as proteins do.
PVPP has E number code E1202 and is used as a stabiliser.
See also
Polyethylene glycol-polyvinyl alcohol |
https://en.wikipedia.org/wiki/Continuing%20medical%20education | Continuing medical education (CME) is continuing education (CE) that helps those in the medical field maintain competence and learn about new and developing areas of their field. These activities may take place as live events, written publications, online programs, audio, video, or other electronic media. Content for these programs is developed, reviewed, and delivered by faculty who are experts in their individual clinical areas. Similar to the process used in academic journals, any potentially conflicting financial relationships for faculty members must be both disclosed and resolved in a meaningful way. However, critics complain that drug and device manufacturers often use their financial sponsorship to bias CMEs towards marketing their own products.
Historical context
Continuing medical education is not a new concept. From essentially the beginning of institutionalized medical instruction (medical instruction affiliated with medical colleges and teaching hospitals), health practitioners continued their learning by meeting with their peers. Grand rounds, case discussions, and meetings to discuss published medical papers constituted the continuing learning experience. In the 1950s through to the 1980s, CME was increasingly funded by the pharmaceutical industry. Concerns regarding informational bias (both intentional and unintentional) led to increasing scrutiny of the CME funding sources. This led to the establishment of certifying agencies such as the Society for Academic Continuing Medical Education which is an umbrella organization representing medical associations and bodies of academic medicine from the United States, Canada, Great Britain and Europe. The pharmaceutical industry has also developed guidelines regarding drug detailing and industry sponsorship of CME, such as the Pharmaceutical Advertising Advisory Board (PAAB) and Canada's Research-Based Pharmaceutical Companies (Rx&D).
Requirements
In the United States, many states require CME for medical p |
https://en.wikipedia.org/wiki/Rejuvenation | Rejuvenation is a medical discipline focused on the practical reversal of the aging process.
Rejuvenation is distinct from life extension. Life extension strategies often study the causes of aging and try to oppose those causes in order to slow aging. Rejuvenation is the reversal of aging and thus requires a different strategy, namely repair of the damage that is associated with aging or replacement of damaged tissue with new tissue. Rejuvenation can be a means of life extension, but most life extension strategies do not involve rejuvenation.
Historical and cultural background
Various myths tell the stories about the quest for rejuvenation. It was believed that magic or intervention of a supernatural power can bring back youth and many mythical adventurers set out on a journey to do that, for themselves, their relatives or some authority that sent them anonymously.
An ancient Chinese emperor actually sent out ships of young men and women to find a pearl that would rejuvenate him. This led to a myth among modern Chinese that Japan was founded by these people.
In some religions, people were to be rejuvenated after death prior to placing them in heaven.
The stories continued well into the 16th century. The Spanish explorer Juan Ponce de León led an expedition around the Caribbean islands and into Florida to find the Fountain of Youth. Led by the rumors, the expedition continued the search and many perished. The Fountain was nowhere to be found as locals were unaware of its exact location.
Since the emergence of philosophy, sages and self-proclaimed wizards always made enormous efforts to find the secret of youth, both for themselves and for their noble patrons and sponsors. It was widely believed that some potions may restore the youth.
Another commonly cited approach was attempting to transfer the essence of youth from young people to old. Some examples of this approach were sleeping with virgins or children (sometimes literally sleeping, not necessarily having |
https://en.wikipedia.org/wiki/Ball%20detent | A ball detent is a simple mechanical arrangement used to hold a moving part in a temporarily fixed position relative to another part. Usually the moving parts slide with respect to each other, or one part rotates within the other.
The ball is a single, usually metal sphere, sliding within a bored cylinder, against the pressure of a spring, which pushes the ball against the other part of the mechanism, which carries the detent - which can be as simple as a hole of smaller diameter than the ball. When the hole is in line with the cylinder, the ball is partially pushed into the hole under spring pressure, holding the parts at that position. Additional force applied to the moving parts will compressing the spring, causing the ball to be depressed back into its cylinder, and allowing the parts to move to another position.
Applications
Ball detents are commonly found in the selector mechanism of a gearbox, holding the selector rods in the correct position to engage the desired gear. Other applications include clutches that slip at a preset torque, and calibrated ball detent mechanisms are typically found in a torque wrench.
Ball detents are one of the mechanisms often used in folding knives to prevent unwanted opening of the blade when carrying.
Ball detents were used in the Curta mechanical calculator to enforce discrete values.
Use in paintball markers
The term "ball detent" is also used when referring to a mechanism in paintball markers designed to prevent the paintball from rolling out of the firing chamber before being fired. Some designs are similar to those outlined above, with a cartridge utilizing a ball bearing in a bore with spring pressure. The cartridge is installed perpendicular to the barrel bore axis, just ahead of where the ball rests before being fired. Other designs use elastic rubber protrusions that block the ball until it is pushed over it by the bolt. Some designs use precisely calibrated rings or "barrel sizers" that are selected to have a s |
https://en.wikipedia.org/wiki/Scatchard%20equation | The Scatchard equation is an equation used in molecular biology to calculate the affinity and number of binding sites of a receptor for a ligand. It is named after the American chemist George Scatchard.
Equation
Throughout this article, [RL] denotes the concentration of a receptor-ligand complex, [R] the concentration of free receptor, and [L] the concentration of free ligand (so that the total concentration of the receptor and ligand are [R]+[RL] and [L]+[RL], respectively). Let n be the number of binding sites for ligand on each receptor molecule, and let represent the average number of ligands bound to a receptor. Let Kd denote the dissociation constant between the ligand and receptor. The Scatchard equation is given by
By plotting /[L] versus , the Scatchard plot shows that the slope equals to -1/Kd while the x-intercept equals the number of ligand binding sites n.
Derivation
n=1 Ligand
When each receptor has a single ligand binding site, the system is described by
with an on-rate (kon) and off-rate (koff) related to the dissociation constant through Kd=koff/kon. When the system equilibrates,
so that the average number of ligands bound to each receptor is given by
which is the Scatchard equation for n=1.
n=2 Ligands
When each receptor has two ligand binding sites, the system is governed by
At equilibrium, the average number of ligands bound to each receptor is given by
which is equivalent to the Scatchard equation.
General Case of n Ligands
For a receptor with n binding sites that independently bind to the ligand, each binding site will have an average occupancy of [L]/(Kd + [L]). Hence, by considering all n binding sites, there will
ligands bound to each receptor on average, from which the Scatchard equation follows.
Problems with the method
The Scatchard method is less used nowadays because of the availability of computer programs that directly fit parameters to binding data. Mathematically, the Scatchard equation is related to Eadie-Hofst |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.