source
stringlengths 32
209
| text
stringlengths 18
1.5k
|
|---|---|
https://en.wikipedia.org/wiki/Indeterminate%20equation
|
In mathematics, particularly in algebra, an indeterminate equation is an equation for which there is more than one solution. For example, the equation is a simple indeterminate equation, as is . Indeterminate equations cannot be solved uniquely. In fact, in some cases it might even have infinitely many solutions. Some of the prominent examples of indeterminate equations include:
Univariate polynomial equation:
which has multiple solutions for the variable in the complex plane—unless it can be rewritten in the form .
Non-degenerate conic equation:
where at least one of the given parameters , , and is non-zero, and and are real variables.
Pell's equation:
where is a given integer that is not a square number, and in which the variables and are required to be integers.
The equation of Pythagorean triples:
in which the variables , , and are required to be positive integers.
The equation of the Fermat–Catalan conjecture:
in which the variables , , are required to be coprime positive integers, and the variables , , and are required to be positive integers satisfying the following equation:
See also
Indeterminate form
Indeterminate system
Indeterminate (variable)
Linear algebra
References
Algebra
|
https://en.wikipedia.org/wiki/Animal%20Diversity%20Web
|
Animal Diversity Web (ADW) is an online database that collects the natural history, classification, species characteristics, conservation biology, and distribution information on thousands of species of animals. The website includes thousands of photographs, hundreds of sound clips, and a virtual museum.
Overview
The ADW acts as an online encyclopedia, with each individual species account displaying basic information specific to that species. The website uses a local, relational database written by staff and student contributors from the University of Michigan. Each species account includes geographic range, habitat, physical description, development, ecosystem roles, reproduction, life span, communication and perception, behavior, food habits, predation, and conservation status. The organization of the site reinforces past biology knowledge by providing sharp images and showing common phyla on the home page.
The Animal Diversity Web has resources other than its database.
The website also offers a virtual museum and a cell phone app.
The virtual museum contains mostly mammals and has a large collection of skulls that can be virtually handled. The Animal Diversity Web is a non-profit site. It is written largely for college students, and also provides resources for K-12 instructors.
Background
The ADW was created in 1995 by Philip Myers, a former biology professor at the University of Michigan. The site contains over 2,150 accounts of animal species along with over 11,50
|
https://en.wikipedia.org/wiki/X-linked%20severe%20combined%20immunodeficiency
|
X-linked severe combined immunodeficiency (X-SCID) is an immunodeficiency disorder in which the body produces very few T cells and NK cells.
In the absence of T cell help, B cells become defective. It is an X-linked recessive inheritance trait, stemming from a mutated (abnormal) version of the IL2RG gene located on the X-chromosome. This gene encodes the interleukin receptor common gamma chain protein, which is a cytokine receptor sub-unit that is part of the receptors for IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21.
Symptoms and signs
People with X-SCID often have infections very early in life, before three months of age. This occurs due to the decreased amount of immunoglobulin G (IgG) levels in the infant during the three-month stage. This is followed by viral infections such as pneumonitis, an inflammation of the lung which produces common symptoms such as cough, fever, chills, and shortness of breath. A telltale sign of X-SCID is candidiasis, a type of fungal infection caused by Candida albicans. Candidiasis involves moist areas of the body such as skin, the mouth, respiratory tract, and vagina; symptoms of oral candidiasis include difficulty in swallowing, pain on swallowing and oral lesions. Recurrent eczema-like rashes are also a common symptom. Other common infections experienced by individuals with X-SCID include diarrhea, sepsis, and otitis media. Some other common symptoms that are experienced by X-SCID patients include failure to thrive, gut problems, skin probl
|
https://en.wikipedia.org/wiki/T7%20DNA%20helicase
|
T7 DNA helicase (gp4) is a hexameric motor protein encoded by T7 phages that uses energy from dTTP hydrolysis to process unidirectionally along single stranded DNA, separating (helicase) the two strands as it progresses. It is also a primase, making short stretches of RNA that initiates DNA synthesis. It forms a complex with T7 DNA polymerase. Its homologs are found in mitochondria (as Twinkle) and chloroplasts.
Crystal structure
The crystal structure was solved to 3.0 Å resolution in 2000, as shown in the figure in the reference. In (A), notice that the separate subunits appear to be anchored through interactions between an alpha helix and an adjacent subunit. In (B), there are six sets of three loops. The red loop, known as loop II, contains three lysine residues and is thought to be involved in binding the ssDNA that is fed through the center of the enzyme.
Mechanism of sequential dTTP hydrolysis
Crampton et al. have proposed a mechanism for the ssDNA-dependent hydrolysis of dTTP by T7 DNA helicase as shown in the figure below. In their model, protein loops located on each hexameric subunit, each of which contain three lysine residues, sequentially interact with the negatively charged phosphate backbone of ssDNA. This interaction presumably causes a conformational change in the actively bound subunit, providing for the efficient release of dTDP from its dTTP binding site. In the process of dTDP release, the ssDNA is transferred to the neighboring subunit, which und
|
https://en.wikipedia.org/wiki/Michael%20Chamberlin%20%28biologist%29
|
Michael John Chamberlin (born June 7, 1937, in Chicago) is a Professor Emeritus of biochemistry and molecular biology at University of California, Berkeley. His research focused on the gene expression in both prokaryotes and eukaryotes. He studied how RNA polymerases initiated and terminated transcription. He became a member of the United States National Academy of Sciences in 1986.
Chamberlin has trained leading molecular biologists who now hold positions throughout academia. Some of his former Ph.D. students include Robert Kingston (Harvard), Karen Arndt (U. Pittsburgh), Alice Telesnitsky (U. Michigan), Tom Kerppola (U. Michigan), John Helmann (Cornell), David Arnosti (Michigan State), Leticia Márquez-Magaña (San Francisco State), and Tracy Johnson (UC San Diego). In 2001, Chamberlin was recognized for his lifelong contribution to scientific research and training with the Sigma Xi Monie A. Ferst Award.
References
Living people
Members of the United States National Academy of Sciences
American biochemists
1937 births
|
https://en.wikipedia.org/wiki/MPACT%202
|
Mpact-2 is a 125 MHz vector-processing graphics, audio and video media processor, a second generation in the Mpact family of Chromatic Research media processors, which can be used only as a co-processor to the main Central Processing Unit (CPU) of a microcomputer.
Hardware using the Mpact-2 uses OEM firmware to provide plug-and-play facility, and may be used with either a PCI or AGP bus.
UAD-1 DSP cards
The UAD-1 was a digital signal processor (DSP) card using the Mpact-2 sold by Universal Audio (acquired by ATI Technologies in November 1998), which uses the DSP, rather than the host computer's CPU, to process audio plug-ins. This allows accurate, but processor-intensive, reverbs, EQs, compressors and limiters to be handled in real time and without burdening the CPU. 3D functionality is hard-wired. The UAD-1 was superseded by the UAD-2, based on the Analog Devices 21369 and 21469 DSPs, in 2009.
UAD-1 hardware was produced with three interfaces: PCI (UAD-1), PCI Express (UAD-1e), and ExpressCard (UAD-Xpander). The cards were offered by Chromatic Research (formerly named Xenon Microsystems), and were part of the Chromatic Mpact 2 Video Adapter.
References
Yao, Yang (18 November 1996). "Chromatic's Mpact 2 Boosts 3D". Microprocessor Report, pp. 1, 6–10.
Digital signal processors
|
https://en.wikipedia.org/wiki/Genomic%20island
|
A genomic island (GI) is part of a genome that has evidence of horizontal origins. The term is usually used in microbiology, especially with regard to bacteria. A GI can code for many functions, can be involved in symbiosis or pathogenesis, and may help an organism's adaptation. Many sub-classes of GIs exist that are based on the function that they confer. For example, a GI associated with pathogenesis is often called a pathogenicity island (PAIs), while GIs that contain many antibiotic resistant genes are referred to as antibiotic resistance islands. The same GI can occur in distantly related species as a result of various types of lateral gene transfer (transformation, conjugation, transduction). This can be determined by base composition analysis, as well as phylogeny estimations.
Computational prediction
Various genomic island predictions programs have been developed. These tools can be broadly grouped into sequence based methods and comparative genomics/phylogeny based methods.
Sequence based methods depend on the naturally occurring variation that exists between the genome sequence composition of different species. Genomic regions that show abnormal sequence composition (such as nucleotide bias or codon bias) suggests that these regions may have been horizontally transferred. Two major problems with these methods are that false predictions can occur due to natural variation in the genome (sometimes due to highly expressed genes) and that horizontally transferred DNA
|
https://en.wikipedia.org/wiki/Yaudheya
|
Yaudheya (Brahmi script: 𑀬𑁅𑀥𑁂𑀬) or Yoddheya Gana (Yoddheya Republic) was an ancient militant confederation based in the Eastern region of the Sapta Sindhu. The word Yaudheya is a derivative of the word from yodha meaning warriors and according to Pāṇini, the suffix '-ya', was significant of warrior tribes, which is supported by their resistance to invading empires such as the Kushan Empire and the Indo-Scythians. Rudradaman I of the Western Satraps notes in his Junagadh rock inscription that the Yaudheyas were 'heroes among all Kshatriya' and 'were loath to surrender'. They were noted as having a republic form of government, unique from other Janapadas which instead maintained monarchies.
Geography
According to Anant Sadashiv Altekar, numismatic evidence indicates that the territorial dominion of the Yaudheyas extended from Bahawalpur in the South-West to Ludhiana in the North-West, encompassing Delhi in the South-East and Saharanpur in the East. However, his research suggests that the Yaudheyas comprised not just one unified entity, but rather three separate republics. In addition to the aforementioned region, another republic was situated in Northern Rajasthan while a further one existed in Northern Pañcāla. He describes the capital as being situated in modern-day Rohtak.
The Bijayagarh pillar inscription of the Yaudheyas, discovered in the Bharatpur district, also serves as further evidence that reinforces the Yaudheyas establishing and maintaining territory within Nort
|
https://en.wikipedia.org/wiki/Linkage%20%28linguistics%29
|
In historical linguistics, a linkage is a network of related dialects or languages that formed from a gradual diffusion and differentiation of a proto-language.
The term was introduced by Malcolm Ross in his study of Western Oceanic languages . It is contrasted with a family, which arises when the proto-language speech community separates into groups that remain isolated from each other and do not form a network.
Principle
Linkages are formed when languages emerged historically from the diversification of an earlier dialect continuum. Its members may have diverged despite sharing subsequent innovations, or such dialects may have come into contact and so converged. In any dialect continuum, innovations are shared between neighbouring dialects in intersecting patterns. The patterns of intersecting innovations continue to be evident as the dialect continuum turns into a linkage.
According to the comparative method, a group of languages that exclusively shares a set of innovations constitutes a "(genealogical) subgroup". A linkage is thus usually characterised by the presence of intersecting subgroups. The tree model does not allow for the existence of intersecting subgroups and so is ill-suited to represent linkages, which are better approached using the wave model.
The cladistic approach underlying the tree model requires the common ancestor of each subgroup to be discontiguous from other related languages and unable to share any innovation with them after their "separation
|
https://en.wikipedia.org/wiki/Four-vertex%20theorem
|
The four-vertex theorem of geometry states that the curvature along a simple, closed, smooth plane curve has at least four local extrema (specifically, at least two local maxima and at least two local minima). The name of the theorem derives from the convention of calling an extreme point of the curvature function a vertex. This theorem has many generalizations, including a version for space curves where a vertex is defined as a point of vanishing torsion.
Definition and examples
The curvature at any point of a smooth curve in the plane can be defined as the reciprocal of the radius of an osculating circle at that point, or as the norm of the second derivative of a parametric representation of the curve, parameterized consistently with the length along the curve. For the vertices of a curve to be well-defined, the curvature itself should vary continuously, as happens for curves of smoothness . A vertex is then a local maximum or local minimum of curvature. If the curvature is constant over an arc of the curve, all points of that arc are considered to be vertices. The four-vertex theorem states that a smooth closed curve always has at least four vertices.
An ellipse has exactly four vertices: two local maxima of curvature where it is crossed by the major axis of the ellipse, and two local minima of curvature where it is crossed by the minor axis. In a circle, every point is both a local maximum and a local minimum of curvature, so there are infinitely many vertices.
Every
|
https://en.wikipedia.org/wiki/Etheric%20force
|
Etheric force is a term Thomas Edison coined to describe a phenomenon later understood as high frequency electromagnetic waves—effectively, radio. Edison believed it was the mysterious force that some believed pervaded the ether.
At the end of 1875, Edison and his assistants were experimenting with the Acoustic Telegraph when they noticed that a rapidly vibrating spark gap produced a spark in an adjacent relay. Subsequent investigation showed that the phenomenon could be made to occur at a distance of several feet without interconnecting cables. Edison, with this small amount of evidence, announced that it was "a true unknown force", since he believed that the spark transmitted electricity without carrying any charge. Edison concluded that this discovery had the potential to cheapen telegraphic communication and to allow transatlantic cables to be laid without insulation. He was also interested in finding new forces as a means for providing scientific explanations for spiritualist, occult and other allegedly supernatural phenomena following his disenchantment with Helena Blavatsky's Theosophy.
Edison's apparatus consisted of a spark gap vibrating at a high frequency powered by batteries and connected to tin foil sheet about 12 by 8 inches, effectively acting as an antenna. A similar tin foil sheet, connected to ground was located at about eight feet away with two more similar, un-grounded tin foil sheets between. Sparks could be seen at the "receiver" sheets. Effectively,
|
https://en.wikipedia.org/wiki/FAUST%20%28programming%20language%29
|
FAUST (Functional AUdio STream) is a domain-specific purely functional programming language for implementing signal processing algorithms in the form of libraries, audio plug-ins, or standalone applications. A FAUST program denotes a signal processor: a mathematical function that is applied to some input signal and then fed out.
Overview
The FAUST programming model combines a functional programming approach with a block diagram syntax:
The functional programming approach provides a natural framework for signal processing. Digital signals are modeled as discrete functions of time, signal processors as second order functions that operate on them, and FAUST's block diagram composition operators, used to combine signal processors together, as third order functions, etc.
Block diagrams, even if purely textual as in FAUST, promote a modular approach to signal processing that complies with sound engineers' and audio developers' habits.
A FAUST program doesn't describe a sound or a group of sounds, but a signal processor. The program source is organized as a set of definitions with at least the definition of the keyword process (the equivalent of main in C):
process = ...;
The FAUST compiler translates FAUST code into a C++ object, which may then interface with other C++ code to produce a full program.
The generated code works at the sample level. It is therefore suited to implement low-level DSP functions like recursive filters. The code may also be embedded. It is self-contain
|
https://en.wikipedia.org/wiki/HSSP
|
HSSP may refer to:
Homology-derived Secondary Structure of Proteins, a protein database
Port Sudan Military Airport, ICAO airport code HSSP, an airport in Sudan
|
https://en.wikipedia.org/wiki/Asymmetric%20dimethylarginine
|
Asymmetric dimethylarginine (ADMA) is a naturally occurring chemical found in blood plasma. It is a metabolic by-product of continual protein modification processes in the cytoplasm of all human cells. It is closely related to L-arginine, a conditionally essential amino acid. ADMA interferes with L-arginine in the production of nitric oxide (NO), a key chemical involved in normal endothelial function and, by extension, cardiovascular health.
Discovery
Patrick Vallance and his London co-workers first noted the interference role for asymmetric dimethylarginine in the early 1990s.
Today biochemical and clinical research continues into the role of ADMA in cardiovascular disease, diabetes mellitus, erectile dysfunction and certain forms of kidney disease.
Synthesis and regulation in the body
Asymmetric dimethylarginine is created in protein methylation, a common mechanism of post-translational protein modification. This reaction is catalyzed by an enzyme set called protein arginine N-methyltransferases 1 and 2 (also known as S-adenosylmethionine protein N-methyltransferases I and II).
The methyl groups transferred to create ADMA are derived from the methyl group donor S-adenosylmethionine, an intermediate in the metabolism of homocysteine. (Homocysteine is an important blood chemical because it is also a marker of cardiovascular disease). After synthesis, ADMA migrates into the extracellular space and thence into blood plasma. Asymmetric dimethylarginine is measured using high
|
https://en.wikipedia.org/wiki/Leaky%20integrator
|
In mathematics, a leaky integrator equation is a specific differential equation, used to describe a component or system that takes the integral of an input, but gradually leaks a small amount of input over time. It appears commonly in hydraulics, electronics, and neuroscience where it can represent either a single neuron or a local population of neurons.
Equation
The equation is of the form
where C is the input and A is the rate of the 'leak'.
General solution
The equation is a nonhomogeneous first-order linear differential equation. For constant C its solution is
where is a constant encoding the initial condition.
References
Differential equations
|
https://en.wikipedia.org/wiki/Tyersal
|
Tyersal is a village east of Bradford and west of Leeds and has a population of 2,605 according to Bradford Community Statistics Project.
The district is split between both City of Bradford metropolitan borough and the City of Leeds metropolitan borough, with east Tyersal sitting in the Pudsey ward of Leeds City Council.
Tyersal joined Bradford in 1882 and part of it became part of the Leeds metropolitan district in 1974.
Shops
On Tyersal Road there are six shops, including a Newsagents, Pharmacy, Sandwich shop, mortgage brokers and a Takeaway.
Transport
Currently there is the 630 service, operated by First Bradford, which terminates at the top. Service 508 from Leeds to Halifax operated also by First Bradford, is every hour along Dick Lane at the bottom of Tyersal. Previously, service 66 (operated by First Leeds and then Centrebus) provided buses to Leeds and back (there were four services daily), although 2010 saw this service withdrawn, and now service 508 is the only remaining bus to Leeds.
New Pudsey railway station is around one and a half miles north-east of the village by road, where services are operated by Northern to Manchester Victoria, Blackpool North, Wakefield Westgate, York and Selby.
Pubs and clubs
Tyersal Residents Association Community Centre
The Quarry Gap public house (Now Quarry Cafe)
Tyersal Park Bowling Club
Crown Green bowling club plays in the Bradford Crown Green Bowling Association.
See also
Listed buildings in Pudsey
External lin
|
https://en.wikipedia.org/wiki/4F
|
4F or 4-F may refer to:
4F (company), a Polish sportswear company
4-F classification in the U.S. Selective Service System, identifying a person as unfit for military service
4F correlator, in Fourier optics
The 4f electron shell
Section 4(f) of the United States DOT act of 1966, which regulates acquiring park and historic properties for transportation use.
4F case, a 4 February 2006 controversial criminal case in Barcelona
Flottille 4F a French naval aviation squadron
LMS Fowler Class 4F, a class of 0-6-0 steam locomotive
February 1992 Venezuelan coup d'état attempt, known in Venezuela as "4F".
See also
F4 (disambiguation)
Four Fs (disambiguation)
|
https://en.wikipedia.org/wiki/Glossoepiglottic%20folds
|
The anterior or lingual surface of the epiglottis is curved forward, and covered on its upper, free part by mucous membrane which is reflected on to the sides and root of the tongue, forming a median and two lateral glossoepiglottic folds; the lateral folds are partly attached to the wall of the pharynx.
Additional Images
References
Tongue
|
https://en.wikipedia.org/wiki/Torus%20tubarius
|
The torus tubarius (or torus of the auditory tube) is an elevation of the mucous membrane of the nasal part of the pharynx formed by the underlying base of the cartilaginous portion of the Eustachian tube (auditory tube). The torus tubarius is situated behind the pharyngeal orifice of the auditory tube.
The torus tubarius is very close to the tubal tonsil, which is sometimes also referred to as the tonsil of (the) torus tubarius. Two folds run anteriorly and posteriorly to the torus tubarius: the salpingopalatine fold (anteriorly), and the salpingopharyngeal fold (posteriorly).
See also
Tubarial salivary gland
References
External links
Ear
|
https://en.wikipedia.org/wiki/QMR
|
QMR may refer to:
QMR.fm, an internet radio station
A Krylov subspace algorithm
The QMR effect
Queen's Medical Review, a student-run publication for Queen's School of Medicine students
Quest Master's Realm - an exciting new Indie MMORPG
|
https://en.wikipedia.org/wiki/Nonparametric%20regression
|
Nonparametric regression is a category of regression analysis in which the predictor does not take a predetermined form but is constructed according to information derived from the data. That is, no parametric form is assumed for the relationship between predictors and dependent variable. Nonparametric regression requires larger sample sizes than regression based on parametric models because the data must supply the model structure as well as the model estimates.
Definition
In nonparametric regression, we have random variables and and assume the following relationship:
where is some deterministic function. Linear regression is a restricted case of nonparametric regression where is assumed to be affine.
Some authors use a slightly stronger assumption of additive noise:
where the random variable is the `noise term', with mean 0.
Without the assumption that belongs to a specific parametric family of functions it is impossible to get an unbiased estimate for , however most estimators are consistent under suitable conditions.
List of general-purpose nonparametric regression algorithms
This is a non-exhaustive list of non-parametric models for regression.
nearest neighbors, see nearest-neighbor interpolation and k-nearest neighbors algorithm
regression trees
kernel regression
local regression
multivariate adaptive regression splines
smoothing splines
neural networks
Examples
Gaussian process regression or Kriging
In Gaussian process regression, also known a
|
https://en.wikipedia.org/wiki/Semiparametric%20regression
|
In statistics, semiparametric regression includes regression models that combine parametric and nonparametric models. They are often used in situations where the fully nonparametric model may not perform well or when the researcher wants to use a parametric model but the functional form with respect to a subset of the regressors or the density of the errors is not known. Semiparametric regression models are a particular type of semiparametric modelling and, since semiparametric models contain a parametric component, they rely on parametric assumptions and may be misspecified and inconsistent, just like a fully parametric model.
Methods
Many different semiparametric regression methods have been proposed and developed. The most popular methods are the partially linear, index and varying coefficient models.
Partially linear models
A partially linear model is given by
where is the dependent variable, is a vector of explanatory variables, is a vector of unknown parameters and . The parametric part of the partially linear model is given by the parameter vector while the nonparametric part is the unknown function . The data is assumed to be i.i.d. with and the model allows for a conditionally heteroskedastic error process of unknown form. This type of model was proposed by Robinson (1988) and extended to handle categorical covariates by Racine and Li (2007).
This method is implemented by obtaining a consistent estimator of and then deriving an estimator of from
|
https://en.wikipedia.org/wiki/Kinesis%20%28biology%29
|
Kinesis, like a taxis or tropism, is a movement or activity of a cell or an organism in response to a stimulus (such as gas exposure, light intensity or ambient temperature).
Unlike taxis, the response to the stimulus provided is non-directional. The animal does not move toward or away from the stimulus but moves at either a slow or fast rate depending on its "comfort zone." In this case, a fast movement (non-random) means that the animal is searching for its comfort zone while a slow movement indicates that it has found it.
Types
There are two main types of kineses, both resulting in aggregations. However, the stimulus does not act to attract or repel individuals.
Orthokinesis: in which the speed of movement of the individual is dependent upon the stimulus intensity. For example, the locomotion of the collembola, Orchesella cincta, in relation to water. With increased water saturation in the soil there is an increase in the direction of its movement towards the aimed place.
Klinokinesis: in which the frequency or rate of turning is proportional to stimulus intensity. For example the behaviour of the flatworm (Dendrocoelum lacteum) which turns more frequently in response to increasing light thus ensuring that it spends more time in dark areas.
Basic model of kinesis
The kinesis strategy controlled by the locally and instantly evaluated well-being (fitness) can be described in simple words: Animals stay longer in good conditions and leave bad conditions more quickly. If
|
https://en.wikipedia.org/wiki/Underactuation
|
Underactuation is a technical term used in robotics and control theory to describe mechanical systems that cannot be commanded to follow arbitrary trajectories in configuration space. This condition can occur for a number of reasons, the simplest of which is when the system has a lower number of actuators than degrees of freedom. In this case, the system is said to be trivially underactuated.
The class of underactuated mechanical systems is very rich and includes such diverse members as automobiles, airplanes, and even animals.
Definition
To understand the mathematical conditions which lead to underactuation, one must examine the dynamics that govern the systems in question. Newton's laws of motion dictate that the dynamics of mechanical systems are inherently second order. In general, these dynamics can be described by a second order differential equation:
Where:
is the position state vector is the vector of control inputs is time.
Furthermore, in many cases the dynamics for these systems can be rewritten to be affine in the control inputs:
When expressed in this form, the system is said to be underactuated if:
When this condition is met, there are acceleration directions that can not be produced no matter what the control vector is.
Note that does not explicitly represent the number of actuators present in the system. Indeed, there may be more actuators than degrees of freedom and the system may still be underactuated. Also worth noting is the dependence
|
https://en.wikipedia.org/wiki/Yttrialite
|
Yttrialite or Yttrialite-(Y) is a rare yttrium thorium sorosilicate mineral with formula: (Y,Th)2Si2O7. It forms green to orange yellow masses with conchoidal fracture. It crystallizes in the monoclinic-prismatic crystal system. It has a Mohs hardness of 5 to 5.5 and a specific gravity of 4.58. It is highly radioactive due to the thorium content.
It is found associated with gadolinite. It was first described in 1889 for an occurrence in the Rode Ranch pegmatite on Baringer Hill, Llano County, Texas. It has also been reported from the Suishouyama pegmatite on Honshū, Japan, and from occurrences in Norway and Sweden.
References
Sorosilicates
Yttrium minerals
Thorium minerals
Monoclinic minerals
Minerals in space group 11
|
https://en.wikipedia.org/wiki/Fluid%20Drive
|
Fluid Drive is the trademarked name that Chrysler Corporation assigned to a transmission driveline combination which replaced the flywheel with a hydraulic coupling and performed the same function as a modern torque converter, only without torque multiplication. A conventional clutch and three- or four-speed manual transmission was installed behind the fluid coupling. Fluid drive was used in many military vehicles produced for the US Armed Forces during the Second World War. It was offered for civilian use from 1939 through 1953 in Chryslers, 1940 through 1953 in DeSotos, and from 1941 through 1954 in Dodge models; a semi-automatic system was optional from Chrysler and Desoto from 1941, and for Dodge from 1949.
History
The fluid coupling and torque converter was invented by the German engineer Foettinger in the early 1900s. For non-marine applications he licensed the development of the fluid coupling to the British engineer Harold Sinclair and his Fluidrive Engineering Co Ltd (now part of Voith AG). Following the development of the fluid coupling, Sinclair in turn licensed the fluid coupling, now also known as "Fluidrive Coupling" to many companies including the Chrysler Corporation.
Many automobile historians confuse Chrysler's Fluid Drive with the Corporation's so-called semi-automatic M5/M6 transmissions, which were marketed under various names as "Simplimatic" (Chrysler), "Tip-Toe Shift" (DeSoto), and "Gyro-Matic" (Dodge). Chrysler contributed to the confusion by ref
|
https://en.wikipedia.org/wiki/Particle%20tracking%20velocimetry
|
Particle tracking velocimetry (PTV) is a velocimetry method i.e. a technique to measure velocities and trajectories of moving objects. In fluid mechanics research these objects are neutrally buoyant particles that are suspended in fluid flow. As the name suggests, individual particles are tracked, so this technique is a Lagrangian approach, in contrast to particle image velocimetry (PIV), which is an Eulerian method that measures the velocity of the fluid as it passes the observation point, that is fixed in space. There are two experimental PTV methods:
the two-dimensional (2-D) PTV. Measurements are made in a 2-D slice, illuminated by a thin laser sheet (a thin plane); a low density of seeded particles allows for tracking each of them individually for several frames.
the three-dimensional particle tracking velocimetry (3-D PTV) is a distinctive experimental technique originally developed to study fully turbulent flows. It is now being used widely in various disciplines, ranging from structural mechanics research to medicine and industrial environments. It is based on a multiple camera-system in a stereoscopic arrangement, three-dimensional illumination of an observation volume, recording of the time sequence of stereoscopic images of optical targets (flow tracers illuminated particles), determining their instantaneous 3-D position in space by use of photogrammetric techniques and tracking their movement in time, thus obtaining a set of 3-D trajectories of the optical tar
|
https://en.wikipedia.org/wiki/Alexander%20Gelfond
|
Alexander Osipovich Gelfond (; 24 October 1906 – 7 November 1968) was a Soviet mathematician. Gelfond's theorem, also known as the Gelfond-Schneider theorem is named after him.
Biography
Alexander Gelfond was born in Saint Petersburg, Russian Empire, the son of a professional physician and amateur philosopher Osip Gelfond. He entered Moscow State University in 1924, started his postgraduate studies there in 1927, and obtained his Ph.D. in 1930. His advisors were Aleksandr Khinchin and Vyacheslav Stepanov.
In 1930, he stayed for five months in Germany (in Berlin and Göttingen) where he worked with Edmund Landau, Carl Ludwig Siegel , and David Hilbert. In 1931 he started teaching as a Professor at the Moscow State University and worked there until the last day of his life. Since 1933 he also worked at the Steklov Institute of Mathematics.
In 1939, he was elected a Corresponding member of the Academy of Sciences of the Soviet Union for his works in the field of Cryptography. According to Vladimir Arnold, during World War II Gelfond was the Chief Cryptographer of the Soviet Navy.
Results
Gelfond obtained important results in several mathematical domains including number theory, analytic functions, integral equations , and the history of mathematics, but his most famous result is his eponymous theorem:
If and are algebraic numbers (with and ), and if is not a real rational number, then any value of is a transcendental number.
This is the famous 7th Hilbert's problem. Ge
|
https://en.wikipedia.org/wiki/Reservation%20station
|
A unified reservation station, also known as unified scheduler, is a decentralized feature of the microarchitecture of a CPU that allows for register renaming, and is used by the Tomasulo algorithm for dynamic instruction scheduling.
Reservation stations permit the CPU to fetch and re-use a data value as soon as it has been computed, rather than waiting for it to be stored in a register and re-read. When instructions are issued, they can designate the reservation station from which they want their input to read. When multiple instructions need to write to the same register, all can proceed and only the (logically) last one need actually be written.
It checks if the operands are available (RAW) and if execution unit is free (Structural hazard) before starting execution.
Instructions are stored with available parameters, and executed when ready. Results are identified by the unit that will execute the corresponding instruction.
Implicitly register renaming solves WAR and WAW hazards. Since this is a fully associative structure, it has a very high cost in comparators (need to compare all results returned from processing units with all stored addresses).
In Tomasulo's algorithm, instructions are issued in sequence to Reservation Stations which buffer the instruction as well as the operands of the instruction. If the operand is not available, the Reservation Station listens on a Common Data Bus for the operand to become available. When the operand becomes available, the Res
|
https://en.wikipedia.org/wiki/Classification%20of%20Thracian
|
The linguistic classification of the ancient Thracian language has long been a matter of contention and uncertainty, and there are widely varying hypotheses regarding its position among other Paleo-Balkan languages. It is not contested, however, that the Thracian languages were Indo-European languages which had acquired satem characteristics by the time they are attested.
Hypothesized links
Daco-Thracian
A Daco-Thracian (or Thraco-Dacian) grouping with Dacian as either the same language or different from Thracian was widely held until the 1950s, but is untenable (according to J. P. Mallory) in light of toponymic evidence: only a percent of place names north of the Danube betray "pan-Thracian" roots. The hypothesis of a Thraco-Dacian or Daco-Thracian branch of IE, indicating a close link between the Thracian and Dacian languages, has numerous adherents, including Russu 1967, Georg Solta 1980, Vraciu 1980, Crossland, Trask (2000), McHenry (1993), Mihailov (2008). Crossland (1982) considers that the divergence of a presumed original Thraco-Dacian language into northern and southern groups of dialects is not so significant as to rank them as separate languages. According to Georg Solta (1982), there is no significant difference between Dacian and Thracian. Rădulescu (1984) accepts that Daco-Moesian possesses a certain degree of dialectal individuality, but argues that there is no fundamental separation between Daco-Moesian and Thracian. Polomé (1982) considers that the evidence
|
https://en.wikipedia.org/wiki/Saputo%20Inc.
|
Saputo Inc. is a Canadian dairy company based in Montreal, Quebec, founded in 1954 by the Saputo family. It produces, markets, and distributes a wide array of dairy products, including cheese, fluid milk, extended shelf-life milk and cream products, cultured products and dairy ingredients and is one of the top ten dairy processors in the world.
The company has expanded predominantly through mergers and acquisitions. Its products are sold in over 60 countries worldwide, operating in Canada, the United States, Argentina, Australia and the United Kingdom, with about half of its revenues coming from its US operations. It operated in Wales and Germany from 2006 to 2013. It used to own the Canadian rights to Hostess Brands products.
History
Master cheesemaker Giuseppe Saputo, his son Lino Saputo and family immigrated to Montreal from Montelepre, Italy, in the early 1950s. In September 1954, Lino convinced his father to start his own business. Using $500 to buy some basic equipment and a bicycle for deliveries, the Saputo family founded a cheesemaking company bearing its name. In 1957, Saputo's first sizable production facility was built in Montreal's Saint-Michel neighbourhood. Saputo went through considerable growth in the 1960s and 1970s as demand for its products increased. It became Canada's largest producer of mozzarella in the 1980s.
In 1988, Saputo expanded to the United States by acquiring two cheese plants. In the 1990s, the company made several acquisitions to divers
|
https://en.wikipedia.org/wiki/Galilei%20number
|
In fluid dynamics, the Galilei number (Ga), sometimes also referred to as Galileo number (see discussion), is a dimensionless number named after Italian scientist Galileo Galilei (1564-1642).
It may be regarded as proportional to gravity forces divided by viscous forces. The Galilei number is used in viscous flow and thermal expansion calculations, for example to describe fluid film flow over walls. These flows apply to condensers or chemical columns.
g: gravitational acceleration, (SI units: m/s2)
L: characteristic length, (SI units: m)
ν: characteristic kinematic viscosity, (SI units: m2/s)
See also
Archimedes number
References
VDI-Wärmeatlas; 5., extended Edition; VDI Verlag Düsseldorf; 1988; page Bc 1 (German)
W. Wagner; Wärmeübertragung; 5., revised Edition; Vogel Fachbuch; 1998; page 119 (German)
External links
Website referring to the Galileo number with calculator
Table of dimensionless numbers (German)
Table of dimensionless numbers (German)
Dimensionless numbers of fluid mechanics
Fluid dynamics
|
https://en.wikipedia.org/wiki/Phospholipid%20scramblase
|
Scramblase is a protein responsible for the translocation of phospholipids between the two monolayers of a lipid bilayer of a cell membrane. In humans, phospholipid scramblases (PLSCRs) constitute a family of five homologous proteins that are named as hPLSCR1–hPLSCR5. Scramblases are not members of the general family of transmembrane lipid transporters known as flippases. Scramblases are distinct from flippases and floppases. Scramblases, flippases, and floppases are three different types of enzymatic groups of phospholipid transportation enzymes. The inner-leaflet, facing the inside of the cell, contains negatively charged amino-phospholipids and phosphatidylethanolamine. The outer-leaflet, facing the outside environment, contains phosphatidylcholine and sphingomyelin. Scramblase is an enzyme, present in the cell membrane, that can transport (scramble) the negatively charged phospholipids from the inner-leaflet to the outer-leaflet, and vice versa.
Expression
Whereas hPLSCR1, -3, and -4 are expressed in a variety of tissues with few exceptions, expression of hPLSCR2 is restricted only to the testis. hPLSCR4 is not expressed in peripheral blood lymphocytes, whereas hPLSCR1 and -3 were not detected in the brain. However, the functional significance of this differential gene expression is not yet understood. While the gene and the mRNA of hPLSCR5 provide evidence of its existence, the protein has yet to be described in the literature.
Structure
Scramblase proteins contain a
|
https://en.wikipedia.org/wiki/Titanium%28III%29%20chloride
|
Titanium(III) chloride is the inorganic compound with the formula TiCl3. At least four distinct species have this formula; additionally hydrated derivatives are known. TiCl3 is one of the most common halides of titanium and is an important catalyst for the manufacture of polyolefins.
Structure and bonding
In TiCl3, each titanium atom has one d electron, rendering its derivatives paramagnetic, that is, the substance is attracted into a magnetic field. Solutions of titanium(III) chloride are violet, which arises from excitations of its d-electron. The colour is not very intense since the transition is forbidden by the Laporte selection rule.
Four solid forms or polymorphs of TiCl3 are known. All feature titanium in an octahedral coordination sphere. These forms can be distinguished by crystallography as well as by their magnetic properties, which probes exchange interactions. β-TiCl3 crystallizes as brown needles. Its structure consists of chains of TiCl6 octahedra that share opposite faces such that the closest Ti–Ti contact is 2.91 Å. This short distance indicates strong metal–metal interactions (see figure in upper right). The three violet "layered" forms, named for their color and their tendency to flake, are called alpha (α), gamma (γ), and delta (δ). In α-TiCl3, the chloride anions are hexagonal close-packed. In γ-TiCl3, the chlorides anions are cubic close-packed. Finally, disorder in shift successions, causes an intermediate between alpha and gamma structures, called
|
https://en.wikipedia.org/wiki/Fetuin
|
Fetuins are blood proteins that are made in the liver and secreted into the bloodstream. They belong to a large group of binding proteins mediating the transport and availability of a wide variety of cargo substances in the bloodstream. Fetuin-A is a major carrier protein of free fatty acids in the circulation. The best known representative of carrier proteins is serum albumin, the most abundant protein in the blood plasma of adult animals. Fetuin is more abundant in fetal blood, hence the name "fetuin" (from Latin, fetus). Fetal bovine serum contains more fetuin than albumin, while adult serum contains more albumin than fetuin.
Family members
Human fetuin is synonymous with α2-HS-glycoprotein (genetic symbol AHSG), α2-HS, A2HS, AHS, HSGA, and fetuin-A. Fetuin-A exists as a single-copy gene in the human and mouse genomes. A closely related gene, fetuin-B, also exists in the human, rat, and mouse genomes. Like fetuin-A, fetuin-B is made predominantly by the liver and to a lesser extent by a number of secretory tissues. Fetuins exist in all vertebrate genomes including fish and reptiles. Fetuins are members of a family of proteins that evolved from the protein cystatin by gene duplication and exchange of gene segments. Fetuins thus belong to the cystatin superfamily of proteins. Fetuin relatives within this superfamily are the histidine-rich glycoprotein (HRG) and kininogen (KNG).
Animal studies
The function of Fetuin-A in the body was determined by gene knockout techn
|
https://en.wikipedia.org/wiki/Frequency-Agile%20Solar%20Radiotelescope
|
Frequency-Agile Solar Radiotelescope (FASR) is a next-generation radio telescope for solar observation in radio and microwave frequency range.
In contrast to other general-purpose radio telescopes, such as the Very Large Array, FASR is specifically designed for solar observations. Compared with other astronomical sources, radio emission from the sun is highly time variable and the range of emission is very high.
The construction site of FASR is not yet determined but it will be somewhere in the southwest United States,
as is its predecessor EOVSA
Radio telescopes
|
https://en.wikipedia.org/wiki/Phosphole
|
Phosphole is the organic compound with the chemical formula ; it is the phosphorus analog of pyrrole. The term phosphole also refers to substituted derivatives of the parent heterocycle. These compounds are of theoretical interest but also serve as ligands for transition metals and as precursors to more complex organophosphorus compounds.
Triphosphole, , is a heterocycle with 3 phosphorus atoms.
Pentaphosphole, , is a cyclic compound with 5 phosphorus atoms.
Structure and bonding
Unlike the related 5-membered heterocycles pyrrole, thiophene, and furan, the aromaticity of phospholes is diminished, reflecting the reluctance of phosphorus to delocalize its lone pair. The main indication of this difference is the pyramidalization of phosphorus. The absence of aromaticity is also indicated by the reactivity of phospholes. Phospholes undergo different cycloaddition reactions; coordination properties of phospholes are also well studied.
Preparation
The parent phosphole was first described in 1983. It was prepared by low-temperature protonation of lithium phospholide. Pentaphenylphosphole was reported in 1953. One route to phospholes is via the McCormack reaction, involving the addition of a 1,3-diene to a phosphonous chloride (RPCl2) followed by dehydrohalogenation. Phenylphospholes can be prepared via zirconacyclopentadienes by reaction with PhPCl2.
Reactivity
The behavior of the secondary phospholes, those with P−H bond, is dominated by the reactivity of this group. The pare
|
https://en.wikipedia.org/wiki/Trace%20scheduling
|
Trace scheduling is an optimization technique developed by Josh Fisher used in compilers for computer programs.
A compiler often can, by rearranging its generated machine instructions for faster execution, improve program performance. It increases ILP (Instruction Level Parallelism) along the important execution path by statically predicting frequent execution path. Trace scheduling is one of many known techniques for doing so.
A trace is a sequence of instructions, including branches but not including loops, that is executed for some input data. Trace scheduling uses a basic block scheduling method to schedule the instructions in each entire trace, beginning with the trace with the highest frequency. It then adds compensation code at the entry and exit of each trace to compensate for any effects that out-of-order execution may have had.
This can result in large increases in code sizes and poor or erratic performance if program's behavior varies significantly with the input.
Trace scheduling was originally developed for Very Long Instruction Word, or VLIW machines, and is a form of global code motion. It works by converting a loop to long straight-line code sequence using loop unrolling and static branch prediction. This process separates out "unlikely" code and adds handlers for exits from trace. The goal is to have the most common case executed as a sequential set of instructions without branches.
See also
Instruction scheduling
References
Compiler optimizations
|
https://en.wikipedia.org/wiki/Block%20upconverter
|
A block upconverter (BUC) is used in the transmission (uplink) of satellite signals. It converts a band of frequencies from a lower frequency to a higher frequency. Modern BUCs convert from the L band to Ku band, C band and Ka band. Older BUCs convert from a 70 MHz intermediate frequency (IF) to Ku band or C band.
Most BUCs use phase-locked loop local oscillators and require an external 10 MHz frequency reference to maintain the correct transmit frequency.
BUCs used in remote locations are often 2 or 4 W in the Ku band and 5 W in the C band. The 10 MHz reference frequency is usually sent on the same feedline as the main carrier. Many smaller BUCs also get their direct current (DC) over the feedline, using an internal DC block.
BUCs are generally used in conjunction with low-noise block converters (LNB). The BUC, being an up-converting device, makes up the "transmit" side of the system, while the LNB is the down-converting device and makes up the "receive" side. An example of a system utilizing both a BUC and an LNB is a VSAT system, used for bidirectional Internet access via satellite.
The block upconverter is a block shaped device assembled with the LNB in association with an OMT, orthogonal mode transducer to the feed-horn that faces the reflector parabolic dish. This is opposed to other types of frequency upconverter which may be rack mounted indoors or not co-located with the dish.
Radio technology
Satellite broadcasting
Telecommunications equipment
|
https://en.wikipedia.org/wiki/Sum-frequency%20generation
|
Sum-frequency generation (SFG) is a second order nonlinear optical process based on the mixing of two input photons at frequencies and to generate a third photon at frequency . As with any optical phenomenon in nonlinear optics, this can only occur under conditions where:
the light is interacting with matter, that lacks centrosymmetry (for example, surfaces and interfaces);
the light has a very high intensity (typically from a pulsed laser).
Sum-frequency generation is a "parametric process", meaning that the photons satisfy energy conservation, leaving the matter unchanged:
Second-harmonic generation
A special case of sum-frequency generation is second-harmonic generation, in which . In fact, in experimental physics, this is the most common type of sum-frequency generation. This is because in second-harmonic generation, only one input light beam is required, but if , two simultaneous beams are required, which can be more difficult to arrange. In practice, the term "sum-frequency generation" usually refers to the less common case in which .
Phase-matching
For sum-frequency generation to occur efficiently, phase-matching conditions must be satisfied:
where are the angular wavenumbers of the three waves as they travel through the medium. (Note that the equation resembles the equation for conservation of momentum.) As this condition is satisfied more and more accurately, the sum-frequency generation becomes more and more efficient.
Sum frequency generation spectroscopy
S
|
https://en.wikipedia.org/wiki/CCL5
|
Chemokine (C-C motif) ligand 5 (also CCL5) is a protein which in humans is encoded by the CCL5 gene. The gene has been discovered in 1990 by in situ hybridisation and it is localised on 17q11.2-q12 chromosome. It is also known as RANTES (regulated on activation, normal T cell expressed and secreted). RANTES was first described by Dr. Tom Schall who named the protein, the original source of the name Rantes was from the Argentine movie Man Facing Southeast about an alien who shows up in a mental ward who was named Rantés, the rather clunky acronym was only made to fit the name.
Function
CCL5 belongs to the CC subfamily of chemokines, due to its adjacent cysteines near N terminus. It is an 8kDa protein acting as a classical chemotactic cytokine or chemokine. It consists of 68 amino acids. CCL5 is proinflammatory chemokine, recruiting leukocytes to the site of inflammation. It is chemotactic for T cells, eosinophils, and basophils, but also for monocytes, natural-killer (NK) cells, dendritic cells and mastocytes. With the help of particular cytokines (i.e., IL-2 and IFN-γ) that are released by T cells, CCL5 also induces the proliferation and activation of certain NK cells to form CHAK (CC-Chemokine-activated killer) cells. It is also an HIV-suppressive factor released from CD8+ T cells
The chemokine CCL5 is mainly expressed by T-cells and monocytes, and it has not been shown to be expressed by B-cells. Moreover, it is abundantly expressed by epithelial cells, fibroblasts a
|
https://en.wikipedia.org/wiki/Optical%20chaos
|
In the field of photonics, optical chaos is chaos generated by laser instabilities using different schemes in semiconductor and fiber lasers. Optical chaos is observed in many non-linear optical systems. One of the most common examples is an optical ring resonators.
Optical computing
Optical chaos was a field of research in the mid-1980s and was aimed at the production of all-optical devices including all-optical computers. Researchers realised later the inherent limitation of the optical systems due to the nonlocalised nature of photons compared to highly localised nature of electrons.
Communications
Research in optical chaos has seen a recent resurgence in the context of studying synchronization phenomena, and in developing techniques for secure optical communications.
References
Photonics
Chaos theory
Nonlinear optics
|
https://en.wikipedia.org/wiki/Gauss%E2%80%93Manin%20connection
|
In mathematics, the Gauss–Manin connection is a connection on a certain vector bundle over a base space S of a family of algebraic varieties . The fibers of the vector bundle are the de Rham cohomology groups of the fibers of the family. It was introduced by for curves S and by in higher dimensions.
Flat sections of the bundle are described by differential equations; the best-known of these is the Picard–Fuchs equation, which arises when the family of varieties is taken to be the family of elliptic curves. In intuitive terms, when the family is locally trivial, cohomology classes can be moved from one fiber in the family to nearby fibers, providing the 'flat section' concept in purely topological terms. The existence of the connection is to be inferred from the flat sections.
Intuition
Consider a smooth morphism of schemes over characteristic 0. If we consider these spaces as complex analytic spaces, then the Ehresmann fibration theorem tells us that each fiber is a smooth manifold and each fiber is diffeomorphic. This tells us that the de-Rham cohomology groups are all isomorphic. We can use this observation to ask what happens when we try to differentiate cohomology classes using vector fields from the base space .
Consider a cohomology class such that where is the inclusion map. Then, if we consider the classes
eventually there will be a relation between them, called the Picard–Fuchs equation. The Gauss–Manin connection is a tool which encodes this informati
|
https://en.wikipedia.org/wiki/Whitecoat
|
A whitecoat is a newborn harp or grey seal with soft, white fur.
From newborn to whitecoat
Newborn seals have yellow fur because of amniotic fluid, and are still wet. When the pup dries, it is called a yellowcoat. The amniotic stain fades and the fur turns white within a few days, and it gets the name whitecoat. First it's called a thin whitecoat, and when it becomes visibly fatter it is a fat whitecoat.
Nursing lasts for about 12 days. Cows frequently return to their pups to suckle. While she is suckling, the mother does not eat—rather, she draws on her reserves of fatty blubber to produce the milk. Pups grow rapidly, at the end of nursing, most pups weigh 36 kg (80 lbs) or more. The mothers then leave their fully fed pups and join the bulls to mate. At this age of about 12 days, pups first become "greycoats", as grey juvenile coloring grows under their white fur, then "ragged-jackets" when white fur begins to fall out in patches.
Hunting of whitecoats
The United States banned the hunting and import of whitecoats in 1972, through the Marine Mammal Protection Act. The European Economic Community banned the import of whitecoat products in 1983. Canada banned the offshore commercial hunting of whitecoats and bluebacks on December 30, 1987.
See also
Grey seal
Harp seal
Seal hunting
References
True seals
Seal hunting
|
https://en.wikipedia.org/wiki/LM317
|
The LM317 is a popular adjustable positive linear voltage regulator. It was designed by Bob Dobkin in 1976 while he worked at National Semiconductor.
The LM337 is the negative complement to the LM317, which regulates voltages below a reference. It was designed by Bob Pease, who also worked for National Semiconductor.
Specifications
Without a heat sink with an ambient temperature at 50 °C such as on a hot summer day inside a box, a maximum power dissipation of (TJ-TA)/RθJA = ((125-50)/80) = 0.98 W can be permitted. (A piece of shiny sheet metal of aluminium with the dimensions 6 x 6 cm and 1.5 mm thick, results in a thermal resistance that permits 4.7 W of heat dissipation).
In a constant voltage mode with an input voltage source at VIN at 34 V and a desired output voltage of 5 V, the maximum output current will be PMAX / (VIN-VO) = 0.98 / (34-5) = 32 mA.
For a constant current mode with an input voltage source at VIN at 12 V and a forward voltage drop of VF=3.6 V, the maximum output current will be PMAX / (VIN - VF) = 0.98 / (12-3.6) = 117 mA.
Operation
As linear regulators, the LM317 and LM337 are used in DC to DC converter applications.
Linear regulators inherently waste power; the power dissipated is the current passed multiplied by the voltage difference between input and output. A LM317 commonly requires a heat sink to prevent the operating temperature from rising too high. For large voltage differences, the power lost as heat can ultimately be greater than that
|
https://en.wikipedia.org/wiki/Proportional%20share%20scheduling
|
Proportional Share Scheduling is a type of scheduling that preallocates certain amount of CPU time to each of the processes. In a proportional share algorithm every job has a weight, and jobs receive a share of the available resources proportional to the weight of every job.
References
Processor scheduling algorithms
|
https://en.wikipedia.org/wiki/List%20of%20interstitial%20cells
|
Interstitial cell refers to any cell that lies in the spaces between the functional cells of a tissue.
Examples include:
Interstitial cell of Cajal (ICC)
Leydig cells, cells present in the male testes responsible for the production of androgen (male sex hormone)
A portion of the stroma of ovary
Certain cells in the pineal gland
Renal interstitial cells
neuroglial cells
See also
List of human cell types derived from the germ layers
References
Sybil B Parker (ed). "Interstitial cell". McGraw Hill Dictionary of Scientific and Technical Terms. Fifth Edition. International Edition. 1994. Page 1041.
Cell biology
Biology-related lists
|
https://en.wikipedia.org/wiki/1%2C9-Pyrazoloanthrone
|
1,9-Pyrazoloanthrone is a chemical compound that is a derivative of anthrone. It is used in biochemical studies as an inhibitor of c-Jun N-terminal kinases (JNKs).
Derivatives of 1,9-pyrazoloanthrone have a variety of biological activities. For example, 5-(aminoalkyl)amino derivatives have been investigated as anticancer agents.
Synthesis
1,9-Pyrazoloanthrone can be synthesized by the condensation of 2-chloroanthraquinone with anhydrous hydrazine in pyridine at 100 °C. Purification is achieved via conversion to the N-acetyl derivative which is crystallized from acetic acid, followed by hydrolysis of the acetyl group with ammonium hydroxide in methanol.
References
Aromatic ketones
Nitrogen heterocycles
Heterocyclic compounds with 4 rings
Tetracyclic compounds
|
https://en.wikipedia.org/wiki/Mattsson
|
Mattsson is a Swedish surname.
Geographical distribution
As of 2014, 79.7% of all known bearers of the surname Mattsson were residents of Sweden (frequency 1:541), 12.0% of Finland (1:2,009), 2.3% of the United States (1:672,721), 1.9% of Denmark (1:12,887) and 1.2% of Norway (1:18,235).
In Sweden, the frequency of the surname was higher than national average (1:541) in the following counties:
1. Blekinge County (1:181)
2. Uppsala County (1:244)
3. Jämtland County (1:268)
4. Dalarna County (1:382)
5. Västernorrland County (1:401)
6. Gävleborg County (1:422)
7. Gotland County (1:464)
8. Värmland County (1:466)
9. Västerbotten County (1:468)
10. Västra Götaland County (1:506)
In Finland, the frequency of the surname was higher than national average (1:2,009) in the following regions:
1. Åland (1:41)
2. Southwest Finland (1:937)
3. Ostrobothnia (1:988)
4. Central Ostrobothnia (1:1,520)
5. Uusimaa (1:1,910)
People
André Mattsson, Swedish ice hockey player
Arne Mattsson, Swedish film director
Frank Mattsson, Finnish composer Oskar Merikanto
Helena Mattsson, a Swedish actress
Lars Eric Mattsson, Finnish musician
Magnus Mattsson, Danish footballer
Markus Mattsson, Finnish ice hockey player
Stein-Erik Mattsson (born 1959), Norwegian lawyer, journalist, and comedian
See also
Matson
Mattson
References
Swedish-language surnames
Patronymic surnames
Surnames from given names
|
https://en.wikipedia.org/wiki/Fluid%20Phase%20Equilibria
|
Fluid Phase Equilibria is a peer-reviewed scientific journal on physical chemistry and thermodynamics that is published by Elsevier. The articles deal with experimental, theoretical and applied research related to properties of pure components and mixtures, especially phase equilibria, caloric and transport properties of fluid and solid phases. It has an impact factor of 2.775 (2020).
Editors
The current editors are:
Clare McCabe - Editor in Chief. Vanderbilt University Department of Chemical and Biomolecular Engineering, Nashville, Tennessee, United States
Ioannis Economou - Texas A&M University at Qatar, Education City, PO Box 23874, Doha, Qatar
Yoshio Iwai - Kyushu University Faculty of Engineering Graduate School of Engineering Department of Chemical Engineering, 744, Motooka, 819-0395, Fukuoka, Japan
Georgios Kontogeorgis - Technical University of Denmark Department of Chemical and Biochemical Engineering, Søltofts Plads, Building 229, DK-2800, Kgs Lyngby, Denmark
Ana Soto - University of Santiago de Compostela School of Engineering, Rúa Lope Gómez de Marzoa s/n, 15782, Santiago de Compostela, Spain
Availability
Fluid Phase Equilibria can be obtained in print or in electronic form.
External links
Elsevier Publisher
Fluid Phase Equilibria Homepage
Chemistry journals
|
https://en.wikipedia.org/wiki/Frequency%20comb
|
In optics, a frequency comb is a laser source whose spectrum consists of a series of discrete, equally spaced frequency lines. Frequency combs can be generated by a number of mechanisms, including periodic modulation (in amplitude and/or phase) of a continuous-wave laser, four-wave mixing in nonlinear media, or stabilization of the pulse train generated by a mode-locked laser. Much work has been devoted to this last mechanism, which was developed around the turn of the 21st century and ultimately led to one half of the Nobel Prize in Physics being shared by John L. Hall and Theodor W. Hänsch in 2005.
The frequency domain representation of a perfect frequency comb is a series of delta functions spaced according to
where is an integer, is the comb tooth spacing (equal to the mode-locked laser's repetition rate or, alternatively, the modulation frequency), and is the carrier offset frequency, which is less than .
Combs spanning an octave in frequency (i.e., a factor of two) can be used to directly measure (and correct for drifts in) . Thus, octave-spanning combs can be used to steer a piezoelectric mirror within a carrier–envelope phase-correcting feedback loop. Any mechanism by which the combs' two degrees of freedom ( and ) are stabilized generates a comb that is useful for mapping optical frequencies into the radio frequency for the direct measurement of optical frequency.
Generation
Using a mode-locked laser
The most popular way of generating a frequency comb is
|
https://en.wikipedia.org/wiki/IGD
|
IGD may stand for:
Internet Gateway Device Protocol as defined in UPnP
İlerici Gençler Derneği, Progressive Young Association of Turkey
Immunoglobulin D, an antibody protein involved in the maturation of B cells
Integrated Graphics Device, a graphics processing unit integrated directly into the motherboard of a PC
Islamic Community of Germany, a religious organization in Germany
It's Going Down (website), a media collective publishing from an anarchist perspective
|
https://en.wikipedia.org/wiki/NeuroNames
|
NeuroNames is an integrated nomenclature for structures in the brain and spinal cord of the four species most studied by neuroscientists: human, macaque, rat and mouse. It offers a standard, controlled vocabulary of common names for structures, which is suitable for unambiguous neuroanatomical indexing of information in digital databases. Terms in the standard vocabulary have been selected for ease of pronunciation, mnemonic value, and frequency of use in recent neuroscientific publications. Structures and their relations to each other are defined in terms of the standard vocabulary. Currently NeuroNames contains standard names, synonyms and definitions of some 2,500 neuroanatomical entities.
The nomenclature is maintained by the University of Washington and is the core component of a tool called "BrainInfo". BrainInfo helps one identify structures in the brain. One can either search by a structure name or locate the structure in a brain atlas and get information such as its location in the classical brain hierarchy, images of the structure, what cells it has, its connections and genes expressed there. Information can be accessed by any of some 16,000 synonyms in eight languages.
NeuroNames is a source vocabulary of the Metathesaurus of the Unified Medical Language System. It is described in depth in the following three scientific articles:
See also
NeuroLex
Neuroscience Information Framework
Talairach coordinates
External links
Overview of NeuroNames
BrainInfo
Ne
|
https://en.wikipedia.org/wiki/Default%20constructor
|
In computer programming languages, the term default constructor can refer to a constructor that is automatically generated by the compiler in the absence of any programmer-defined constructors (e.g. in Java), and is usually a nullary constructor. In other languages (e.g. in C++) it is a constructor that can be called without having to provide any arguments, irrespective of whether the constructor is auto-generated or user-defined. Note that a constructor with formal parameters can still be called without arguments if default arguments were provided in the constructor's definition.
C++
In C++, the standard describes the default constructor for a class as a constructor that can be called with no arguments (this includes a constructor whose parameters all have default arguments). For example:
class MyClass
{
public:
MyClass(); // constructor declared
private:
int x;
};
MyClass::MyClass() : x(100) // constructor defined
{
}
int main()
{
MyClass m; // at runtime, object m is created, and the default constructor is called
}
When allocating memory dynamically, the constructor may be called by adding parenthesis after the class name. In a sense, this is an explicit call to the constructor:
int main()
{
MyClass * pointer = new MyClass(); // at runtime, an object is created, and the
// default constructor is called
}
If the constructor does have one or more parameters, but they all have default values, then it is still
|
https://en.wikipedia.org/wiki/Eikonal%20equation
|
An eikonal equation (from Greek εἰκών, image) is a non-linear first-order partial differential equation that is encountered in problems of wave propagation.
The classical eikonal equation in geometric optics is a differential equation of the form
where lies in an open subset of , is a
positive function, denotes the gradient, and is the Euclidean norm. The function is given and one seeks solutions .
In the context of geometric optics, the function is the refractive index of the medium.
More generally, an eikonal equation is an equation of the form
where is a function of variables.
Here the function is given, and is the solution.
If , then equation () becomes ().
Eikonal equations naturally arise in the WKB method
and the study of Maxwell's equations. Eikonal equations provide a link between physical (wave) optics and geometric (ray) optics.
One fast computational algorithm to approximate the solution to the eikonal equation is the fast marching method.
History
The term "eikonal" was first used in the context of geometric optics by Heinrich Bruns. However,
the actual equation appears earlier in the seminal work of William Rowan Hamilton on geometric optics.
Physical interpretation
Continuous shortest-path problems
Suppose that is an open set with suitably smooth boundary .
The solution to the eikonal equation
can be interpreted as the minimal amount of time required to travel from to , where is the speed of travel, and is an exit-time penalty. (
|
https://en.wikipedia.org/wiki/Fifteenth
|
In music, a fifteenth or double octave, abbreviated 15ma, is the interval between one musical note and another with one-quarter the wavelength or quadruple the frequency. It has also been referred to as the bisdiapason. The fourth harmonic, it is two octaves. It is referred to as a fifteenth because, in the diatonic scale, there are 15 notes between them if one counts both ends (as is customary). Two octaves (based on the Italian word for eighth) do not make a sixteenth, but a fifteenth. In other contexts, the term two octaves is likely to be used.
For example, if one note has a frequency of 400 Hz, the note a fifteenth above it is at 1600 Hz (15ma ), and the note a fifteenth below is at 100 Hz (15mb ). The ratio of frequencies of two notes a fifteenth apart is therefore 4:1.
As the fifteenth is a multiple of octaves, the human ear tends to hear both notes as being essentially "the same", as it does the octave. Like the octave, in the Western system of music notation notes a fifteenth apart are given the same name—the name of a note an octave above A is also A. However, because of the large frequency distance between the notes, it is less likely than an octave to be judged the same pitch by non-musicians. Passages in parallel fifteenths are much less common than parallel octaves. In particular, sometimes an organist will use two stops a fifteenth away (notated as 2′).
15ma notation
Like the notation 8va for octave (), 15ma () means "play two octaves higher than written." I
|
https://en.wikipedia.org/wiki/WMDB
|
WMDB is a Regional Mexican-format AM radio station broadcasting on a frequency of 880 kHz in Nashville, Tennessee. The station's power is 2,500 watts during the daytime hours. The station is currently owned by Mahan Janbakhsh, through licensee TBLC Media #2, LLC. Nighttime power is reduced to 2 watts to protect the signal of WCBS in New York, New York. WCBS is the dominant Class A signal on 880 AM.
History
WMDB signed on the air in 1983 under the original owner, Reverend Morgan Babb. It was a black-oriented station with urban gospel in the morning, transitioning to secular rhythm & blues in the afternoon. Morgan Babb came up with the station's popular moniker slogan "The Big Mouth", because of WMDB's large daytime signal. Morgan Babb also claimed his secular R&B format was the "rock lite" format, drawing not just black listeners, but many white listeners as well. By 2000, the music format also included Hip Hop.
In May of 2005, Reverend Morgan Babb sold WMDB to Peter Davison of Davidson Media Group, based out of Charlotte, North Carolina, according to FCC Records. The FCC granted the transfer of WMDB's license July 5th, 2005. During this time period, Davidson Media Group purchased AM 1240, (then WNSG) in the Nashville Market. Davidson Media Changed WNSG's call sign to WNVL on September 21, 2005. Shortly afterwards, Davidson Media Group would eventually flip both WMDB and WNVL to Spanish Language Formats.
References
External links
MDB
Radio stations established in 1960
196
|
https://en.wikipedia.org/wiki/West%20Iron%20County%20Schools
|
The West Iron County School District is one of two school districts in Iron County, Michigan (the other is the Forest Park School District in Crystal Falls, Michigan). Their mascot is the Wykon. The schools include Stambaugh Elementary School and West Iron County Middle and High School.
External links
West Iron County Schools website
School districts in Michigan
Education in Iron County, Michigan
|
https://en.wikipedia.org/wiki/LBM
|
LBM may refer to:
Laboratory of biomechanics of Arts et Métiers ParisTech
Interleaved Bitmap Format filename extension
Lattice Boltzmann methods in fluid dynamics
Pound (mass), lbm or lbm
Lean body mass
Location-based media
London Borough of Merton, UK
Laser beam machining
Logical Business Machines, a defunct computer company
Little Brown Mushroom, a publishing house founded by Alec Soth
Live bivalve mollusc
Lumber and Building Materials
|
https://en.wikipedia.org/wiki/WNRQ
|
WNRQ is an FM radio station in Nashville, Tennessee, broadcasting on a frequency of 105.9 MHz. Owned and operated by iHeartMedia, it serves counties in northern middle Tennessee and southern central Kentucky. The station's studios are located in Nashville's Music Row district and the transmitter site is located in Brentwood, Tennessee, a Nashville suburb.
History/ownership
WNRQ has previously been the adult contemporary "Star 106," WLAC-FM; the album oriented rock "Rock 106," WKQB; and "The Joy of Nashville," WJYN, the latter reflecting a former easy listening format. Since 1964 it has been the partner station of the historical AM station WLAC, through numerous ownership changes.
In 1998, Dick Broadcasting, owner of WGFX, and SFX Broadcasting, the then-owner of WLAC-FM, agreed to trade the intellectual property of the stations. The trade, to have taken place February 2, 1998, would have moved WLAC-FM to 104.5 FM, and moved WGFX's classic rock format to 105.9 under SFX ownership. However, when the agreement fell apart, SFX decided to go ahead with launching a classic rock format anyway, and flipped WLAC-FM to WNRQ on January 30.
Current format
The current format features a mixture of fairly hard classic rock deemed to be primarily male-oriented; most of the station's playlist first hit middle Tennessee airwaves on the now-country-formatted WKDF during the 1970s and 1980s, as well as WKQB, "Rock 106" (from 1978 to 1981). It was also Nashville's station for the syndicated Joh
|
https://en.wikipedia.org/wiki/Short%20hairpin%20RNA
|
A short hairpin RNA or small hairpin RNA (shRNA/Hairpin Vector) is an artificial RNA molecule with a tight hairpin turn that can be used to silence target gene expression via RNA interference (RNAi). Expression of shRNA in cells is typically accomplished by delivery of plasmids or through viral or bacterial vectors. shRNA is an advantageous mediator of RNAi in that it has a relatively low rate of degradation and turnover. However, it requires use of an expression vector, which has the potential to cause side effects in medicinal applications.
The promoter choice is essential to achieve robust shRNA expression. At first, polymerase III promoters such as U6 and H1 were used; however, these promoters lack spatial and temporal control. As such, there has been a shift to using polymerase II promoters, which are inducible, to regulate shRNA expression.
Delivery
Expression of shRNA in cells can be obtained by delivery of plasmids or through viral or bacterial vectors.
Delivery of plasmids to cells through transfection to obtain shRNA expression can be accomplished using commercially available reagents in vitro. However, this method is not applicable in vivo and thus has limited utility.
Use of a bacterial vector to obtain shRNA expression in cells is a relatively recent approach. It builds off research showing that recombinant Escherichia coli, containing a plasmid with shRNA, fed to mice can knock-down target gene expression in the intestinal epithelium. This approach was use
|
https://en.wikipedia.org/wiki/Scipione%20del%20Ferro
|
Scipione del Ferro (6 February 1465 – 5 November 1526) was an Italian mathematician who first discovered a method to solve the depressed cubic equation.
Life
Scipione del Ferro was born in Bologna, in northern Italy, to Floriano and Filippa Ferro. His father, Floriano, worked in the paper industry, which owed its existence to the invention of the press in the 1450s and which probably allowed Scipione to access various works during the early stages of his life. He married and had a daughter, who was named Filippa after his mother.
He likely studied at the University of Bologna, where he was appointed a lecturer there in Arithmetic and Geometry in 1496. During his last years, he also undertook commercial work.
Diffusion of his work
There are no surviving scripts from del Ferro. This is in large part due to his resistance to communicating his works. Instead of publishing his ideas, he would only show them to a small, select group of friends and students.
It is suspected that this is due to the practice of mathematicians at the time of publicly challenging one another. When a mathematician accepted another's challenge, each mathematician needed to solve the other's problems. The loser in a challenge often lost funding or his university position. Del Ferro was fearful of being challenged and likely kept his greatest work secret so that he could use it to defend himself in the event of a challenge.
Despite this secrecy, he had a notebook where he recorded all his important di
|
https://en.wikipedia.org/wiki/Mycolic%20acid
|
Mycolic acids are long fatty acids found in the cell walls of the Mycolata taxon, a group of bacteria that includes Mycobacterium tuberculosis, the causative agent of the disease tuberculosis. They form the major component of the cell wall of mycolata species. Despite their name, mycolic acids have no biological link to fungi; the name arises from the filamentous appearance their presence gives mycolata under high magnification. The presence of mycolic acids in the cell wall also gives mycolata a distinct gross morphological trait known as "cording". Mycolic acids were first isolated by Stodola et al. in 1938 from an extract of M. tuberculosis.
Mycolic acids are composed of a longer beta-hydroxy chain with a shorter alpha-alkyl side chain. Each molecule contains between 60 and 90 carbon atoms. The exact number of carbons varies by species and can be used as an identification aid. Most mycolic acids also contain various functional groups.
Mycolic acids of M. tuberculosis
M. tuberculosis produces three main types of mycolic acids: alpha-, methoxy-, and keto-. Alpha-mycolic acids make up at least 70% of the mycolic acids of the organism and contain several cyclopropane rings. Methoxy-mycolic acids, which contain several methoxy groups, constitute between 10% and 15% of the mycolic acids in the organism. The remaining 10% to 15% of the mycolic acids are keto-mycolic acids, which contain several ketone groups.
Mycolic acids impart M. tuberculosis with unique properti
|
https://en.wikipedia.org/wiki/Radian%20per%20second
|
The radian per second (symbol: rad⋅s−1 or rad/s) is the unit of angular velocity in the International System of Units (SI). The radian per second is also the SI unit of angular frequency (symbol ω, omega). The radian per second is defined as the angular frequency that results in the angular displacement increasing by one radian every second.
Relation to other units
A frequency of one hertz (1 Hz), or one cycle per second (1 cps), corresponds to an angular frequency of 2 radians per second. This is because one cycle of rotation corresponds to an angular rotation of 2 radians.
Since the radian is a dimensionless unit in the SI, the radian per second is dimensionally equivalent to the hertz—both can be expressed as reciprocal seconds, s−1. So, context is necessary to specify which kind of quantity is being expressed, angular frequency or ordinary frequency.
One radian per second also corresponds to about 9.55 revolutions per minute. Degrees per second may also be defined, based on degree of arc.
{| class="wikitable"
|+ Quantity correspondence
|-
! Angular frequency !! Frequency
|-
|| 2π rad/s ||1 Hz
|-
|| 1 rad/s || ≈ 0.159155 Hz
|-
|| 1 rad/s || ≈ 9.5493 rpm
|-
|| 0.1047 rad/s || ≈ 1 rpm
|-
|}
Coherent units
A use of the unit radian per second is in calculation of the power transmitted by a shaft. In the International System of Quantities (SI) and the International System of Units, widely used in physics and engineering, the power p is equal to the angular speed ω mul
|
https://en.wikipedia.org/wiki/Bartok%20%28compiler%29
|
Bartok is an optimizing compiler and managed runtime system for Common Intermediate Language (which .NET languages compile to), being developed by Microsoft Research.
Overview
Bartok aims to be efficient enough to be usable for writing operating systems. It provides services such as automatic memory management and garbage collection, threading, and marshalling data to and from native code, as well as verification of CIL code. Bartok is written in C#, including the garbage collector. Bartok is being used by Microsoft Research for the implementation of Singularity, a highly-dependable operating system written almost entirely in managed code.
Bartok allows various implementations of the garbage collector, base class library and other components to be chosen at runtime on a per-application basis. This feature is being used to write the different components of Singularity – kernel, device drivers, and applications – each using a separate class library that exposes functionality required by (and optimized for) the specific usage.
See also
Roslyn (compiler)
List of compilers
References
Further reading
External links
Microsoft Research
Compilers
Microsoft initiatives
Microsoft Research
|
https://en.wikipedia.org/wiki/Ruby%20laser
|
A ruby laser is a solid-state laser that uses a synthetic ruby crystal as its gain medium. The first working laser was a ruby laser made by Theodore H. "Ted" Maiman at Hughes Research Laboratories on May 16, 1960.
Ruby lasers produce pulses of coherent visible light at a wavelength of 694.3 nm, which is a deep red color. Typical ruby laser pulse lengths are on the order of a millisecond.
Design
A ruby laser most often consists of a ruby rod that must be pumped with very high energy, usually from a flashtube, to achieve a population inversion. The rod is often placed between two mirrors, forming an optical cavity, which oscillate the light produced by the ruby's fluorescence, causing stimulated emission. Ruby is one of the few solid state lasers that produce light in the visible range of the spectrum, lasing at 694.3 nanometers, in a deep red color, with a very narrow linewidth of 0.53 nm.
The ruby laser is a three level solid state laser. The active laser medium (laser gain/amplification medium) is a synthetic ruby rod that is energized through optical pumping, typically by a xenon flashtube. Ruby has very broad and powerful absorption bands in the visual spectrum, at 400 and 550 nm, and a very long fluorescence lifetime of 3 milliseconds. This allows for very high energy pumping, since the pulse duration can be much longer than with other materials. While ruby has a very wide absorption profile, its conversion efficiency is much lower than other mediums.
In early examp
|
https://en.wikipedia.org/wiki/Fumarase%20deficiency
|
Fumarase deficiency (or fumaric aciduria) is an exceedingly rare autosomal recessive metabolic disorder in the Krebs cycle, characterized by a deficiency of the enzyme fumarate hydratase, which causes a buildup of fumaric acid in the urine and a deficiency of malate. Only 13 cases were known worldwide in 1990, after which a cluster of 20 cases was documented in a community in Arizona that has practiced successive endogamy.
Presentation
Fumarase deficiency causes encephalopathy, severe intellectual disabilities, unusual facial features, brain malformation, and epileptic seizures due to an abnormally low amount of fumarase in cells. It can initially present with polyhydramnios on prenatal ultrasound. Affected neonates may demonstrate nonspecific signs of poor feeding and hypotonia. Laboratory findings in neonates may indicate polycythemia, leukopenia, or neutropenia. As they age, neurological deficits begin to manifest with seizures, dystonias, and severe developmental delay.
Pathophysiology
Fumarase deficiency is caused by a mutation in the fumarate hydratase (FH) gene in humans, which encodes the enzyme that converts fumarate to malate in the mitochondria. Other mutant alleles of the FH gene, located on human Chromosome 1 at position 1q42.1, cause multiple cutaneous and uterine leiomyomata, hereditary leiomyomatosis and renal cell cancer. Fumarase deficiency is one of the few known deficiencies of the Krebs cycle or tricarboxylic acid cycle, the main enzymatic pathway of
|
https://en.wikipedia.org/wiki/Rabbit%20%28cipher%29
|
Rabbit is a high-speed stream cipher from 2003. The algorithm and source code was released in 2008 as public domain software.
History
Rabbit was first presented in February 2003 at the 10th FSE workshop. In May 2005, it was submitted to the eSTREAM project of the ECRYPT network.
Rabbit was designed by Martin Boesgaard, Mette Vesterager, Thomas Pedersen, Jesper Christiansen and Ove Scavenius.
The authors of the cipher have provided a full set of cryptanalytic white papers on the Cryptico home page. It is also described in RFC 4503. Cryptico had patents pending for the algorithm and for many years required a license fee for commercial use of the cipher which was waived for non-commercial uses. However, the algorithm was made free for any use on October 6, 2008. Also the website states that the algorithm and implementation is public domain software and offers the source code free for download.
Functionality
Rabbit uses a 128-bit key and a 64-bit initialization vector. The cipher was designed with high performance in software in mind, where fully optimized implementations achieve an encryption cost of up to 3.7 cpb on a Pentium 3, and of 9.7 cpb on an ARM7. However, the cipher also turns out to be very fast and compact in hardware.
The core component of the cipher is a bitstream generator which encrypts 128 message bits per iteration. The cipher's strength rests on a strong mixing of its inner state between two consecutive iterations. The mixing function is entirely based
|
https://en.wikipedia.org/wiki/Glitch%20%28astronomy%29
|
A glitch is a sudden increase (around 1 part in 106) in the rotational frequency of a pulsar, which usually decreases steadily due to braking provided by the emission of radiation and high-energy particles. It is unknown whether they are related to the timing noise which all pulsars exhibit. Following a glitch is a period of gradual recovery where the observed periodicity slows to a period close to that observed before the glitch. These gradual recovery periods have been observed to last from days to years. Currently, only multiple glitches of the Crab and Vela pulsars have been observed and studied extensively.
Cause
While the exact cause of glitches is unknown, they are thought to be caused by an internal process within the pulsar. This differs from the steady decrease in the star's rotational frequency which is caused by external processes. Although the details of the glitch process are unknown, it is thought that the resulting increase in the pulsar's rotational frequency is caused by a brief coupling of the pulsar's faster-spinning superfluid core to the crust, which are usually decoupled. This brief coupling transfers angular momentum from core to the surface, which causes a decrease in the measured period.
Implications
Assuming that the mechanism described above is correct, observed pulsar glitches set a limit on the moment of inertia of the pulsar being observed and, thus, the mass-radius relation possible in dense nuclear matter. From extrapolating from a
|
https://en.wikipedia.org/wiki/Capacitance%E2%80%93voltage%20profiling
|
Capacitance–voltage profiling (or C–V profiling, sometimes CV profiling) is a technique for characterizing semiconductor materials and devices. The applied voltage is varied, and the capacitance is measured and plotted as a function of voltage. The technique uses a metal–semiconductor junction (Schottky barrier) or a p–n junction or a MOSFET to create a depletion region, a region which is empty of conducting electrons and holes, but may contain ionized donors and electrically active defects or traps. The depletion region with its ionized charges inside behaves like a capacitor. By varying the voltage applied to the junction it is possible to vary the depletion width. The dependence of the depletion width upon the applied voltage provides information on the semiconductor's internal characteristics, such as its doping profile and electrically active defect densities.,
Measurements may be done at DC, or using both DC and a small-signal AC signal (the conductance method
, ), or using a large-signal transient voltage.
Application
Many researchers use capacitance–voltage (C–V) testing to determine semiconductor parameters, particularly in MOSCAP and MOSFET structures. However, C–V measurements are also widely used to characterize other types of semiconductor devices and technologies, including bipolar junction transistors, JFETs, III–V compound devices, photovoltaic cells, MEMS devices, organic thin-film transistor (TFT) displays, photodiodes, and carbon nanotubes (CNTs).
These
|
https://en.wikipedia.org/wiki/Hamming%20space
|
In statistics and coding theory, a Hamming space (named after American mathematician Richard Hamming) is usually the set of all binary strings of length N. It is used in the theory of coding signals and transmission.
More generally, a Hamming space can be defined over any alphabet (set) Q as the set of words of a fixed length N with letters from Q. If Q is a finite field, then a Hamming space over Q is an N-dimensional vector space over Q. In the typical, binary case, the field is thus GF(2) (also denoted by Z2).
In coding theory, if Q has q elements, then any subset C (usually assumed of cardinality at least two) of the N-dimensional Hamming space over Q is called a q-ary code of length N; the elements of C are called codewords. In the case where C is a linear subspace of its Hamming space, it is called a linear code. A typical example of linear code is the Hamming code. Codes defined via a Hamming space necessarily have the same length for every codeword, so they are called block codes when it is necessary to distinguish them from variable-length codes that are defined by unique factorization on a monoid.
The Hamming distance endows a Hamming space with a metric, which is essential in defining basic notions of coding theory such as error detecting and error correcting codes.
Hamming spaces over non-field alphabets have also been considered, especially over finite rings (most notably over Z4) giving rise to modules instead of vector spaces and ring-linear codes (identif
|
https://en.wikipedia.org/wiki/Tameness%20theorem
|
In mathematics, the tameness theorem states that every complete hyperbolic 3-manifold with finitely generated fundamental group is topologically tame, in other words homeomorphic to the interior of a compact 3-manifold.
The tameness theorem was conjectured by . It was proved by and, independently, by Danny Calegari and David Gabai. It is one of the fundamental properties of geometrically infinite hyperbolic 3-manifolds, together with the density theorem for Kleinian groups and the ending lamination theorem.
It also implies the Ahlfors measure conjecture.
History
Topological tameness may be viewed as a property of the ends of the manifold, namely, having a local product structure. An analogous statement is well known in two dimensions, that is, for surfaces. However, as the example of Alexander horned sphere shows, there are wild embeddings among 3-manifolds, so this property is not automatic.
The conjecture was raised in the form of a question by Albert Marden, who proved that any geometrically finite hyperbolic 3-manifold is topologically tame. The conjecture was also called the Marden conjecture or the tame ends conjecture.
There had been steady progress in understanding tameness before the conjecture was resolved. Partial results had been obtained by Thurston, Brock, Bromberg, Canary, Evans, Minsky, Ohshika. An important sufficient condition for tameness in terms of splittings of the fundamental group had been obtained by Bonahon.
The conjecture was proved in 2004
|
https://en.wikipedia.org/wiki/Philippe%20V%C3%A9ron
|
Philippe Véron (2 March 1939 – 7 August 2014) was a French astronomer. He worked at Observatoire de Haute Provence, where he was director from 1985 to 1994.
He studied variability and statistics of quasars, as well as elliptical galaxies. He was married to French astronomer Marie-Paule Véron-Cetty, and together with her compiled and maintained the Veron-Cetty Catalog of Quasars and Active Galactic Nuclei, whose thirteenth edition was published in 2010.
At the time of his death, he was working on the Dictionnaire des Astronomes Français 1850–1950 (Dictionary of French astronomers 1850–1950), which is a biographical encyclopedia. It is unpublished but is available online in PDF form at http://www.obs-hp.fr/dictionnaire.
Asteroid 5260 Philvéron is named after him.
References
External links
Recent publications, form NASA Astrophysics Data System website
20th-century French astronomers
1939 births
2014 deaths
21st-century French astronomers
|
https://en.wikipedia.org/wiki/Skilpadjies
|
Skilpadjies is a traditional South African food, also known by other names such as and .
The dish is lamb's liver wrapped in (caul fat), which is the fatty membrane that surrounds the kidneys. Most cooks mince the liver, add coriander, chopped onion, salt and Worcestershire sauce then wrap balls of this mixture with the and secure it with a toothpick. The balls, approximately in diameter, are normally barbecued (grilled over an open fire) and ready when the fat is crisp.
Dishes such as skilpadjies had already been made by the ancient Romans and the German recipe for calf's liver in caul fat appears in the book "Das Buoch von guoter Spise".
The names (little tortoise), (mice), (bats) and (puff adder) reflect its appearance. is the largest version, the size of a man's forearm. It is made from minced lamb's liver wrapped in a large piece of , and is usually served at parties where about 8 to 10 servings can be sliced from one when grilled.
It is a very rich, high cholesterol and fatty food; the consumers normally eat some starchy food in the form of mealie pap or toasted bread with the skilpadjies, so as not to attract some symptoms of over-indulgence.
See also
List of African dishes
List of lamb dishes
List of meatball dishes
Boerewors
Meat chop
Meat on the bone
Steak
Pork steak
References
South African cuisine
Offal
Lamb dishes
Meatballs
|
https://en.wikipedia.org/wiki/CSG%2065CE02
|
The CSG 65CE02 is an 8/16-bit microprocessor developed by Commodore Semiconductor Group in 1988. It is a member of the MOS Technology 6502 family, developed from the CMOS WDC 65C02 released by the Western Design Center in 1983.
Like the 65C02, the 65CE02 was built on a 2 µm CMOS process instead of the original 6502's 8 µm NMOS technology, making the chip smaller (and thus less expensive) as well as using much less power. In addition to changes made in the 65C02, the 65CE02 also included improvements to the processor pipeline to allow one-byte instructions to complete in 1 cycle, rather than the 6502's (and most variants) minimum of 2 cycles. It also removed 1 cycle delays when crossing page boundaries. These changes improved performance as much as 25% at the same clock speed.
Other changes included the addition of a third index register, Z, along with the addition and modification of a number of instructions to use this register. The zero-page, the first 256 bytes of memory that were used as pseudo-registers, could now be moved to any page in main memory using the B(ase page) register. The stack register was widened from 8 to 16-bits using a similar page register, SPH (stack pointer high), allowing the stack to be moved out of page one and to grow to larger sizes.
The 65CE02 was the basis for the system on a chip CSG 4510 that was developed for the unreleased Commodore 65. The 65CE02 was later used for the A2232 serial port card for the Amiga computer. It appears to have s
|
https://en.wikipedia.org/wiki/Transfer%20matrix
|
In applied mathematics, the transfer matrix is a formulation in terms of a block-Toeplitz matrix of the two-scale equation, which characterizes refinable functions. Refinable functions play an important role in wavelet theory and finite element theory.
For the mask , which is a vector with component indexes from to ,
the transfer matrix of , we call it here, is defined as
More verbosely
The effect of can be expressed in terms of the downsampling operator "":
Properties
See also
Hurwitz determinant
References
(contains proofs of the above properties)
Wavelets
Numerical analysis
|
https://en.wikipedia.org/wiki/Anderson%27s%20rule
|
Anderson's rule is used for the construction of energy band diagrams of the heterojunction between two semiconductor materials. Anderson's rule states that when constructing an energy band diagram, the vacuum levels of the two semiconductors on either side of the heterojunction should be aligned (at the same energy).
It is also referred to as the electron affinity rule, and is closely related to the Schottky–Mott rule for metal–semiconductor junctions.
Anderson's rule was first described by R. L. Anderson in 1960.
Constructing energy band diagrams
Once the vacuum levels are aligned it is possible to use the electron affinity and band gap values for each semiconductor to calculate the conduction band and valence band offsets. The electron affinity (usually given by the symbol in solid state physics) gives the energy difference between the lower edge of the conduction band and the vacuum level of the semiconductor. The band gap (usually given the symbol ) gives the energy difference between the lower edge of the conduction band and the upper edge of the valence band. Each semiconductor has different electron affinity and band gap values. For semiconductor alloys it may be necessary to use Vegard's law to calculate these values.
Once the relative positions of the conduction and valence bands for both semiconductors are known, Anderson's rule allows the calculation of the band offsets of both the valence band () and the conduction band ().
After applying Anderson's rule a
|
https://en.wikipedia.org/wiki/Brahmagupta%27s%20problem
|
This problem was given in India by the mathematician Brahmagupta in 628 AD in his treatise Brahma Sputa Siddhanta:
Solve the Pell's equation
for integers .
Brahmagupta gave the smallest solution as
.
See also
Brahmagupta
Indian mathematics
List of Indian mathematicians
Pell's equation
Indeterminate equation
Diophantine equation
External links
Brahmagupta
Diophantine equations
|
https://en.wikipedia.org/wiki/Deterministic%20parsing
|
In natural language processing, deterministic parsing refers to parsing algorithms that do not backtrack. LR-parsers are an example. (This meaning of the words "deterministic" and "non-deterministic" differs from that used to describe nondeterministic algorithms.)
The deterministic behavior is desired and expected in compiling programming languages. In natural language processing, it was thought for a long time that deterministic parsing is impossible due to ambiguity inherent in natural languages (many sentences have more than one plausible parse). Thus, non-deterministic approaches such as the chart parser had to be applied. However, Mitch Marcus proposed in 1978 the Parsifal parser that was able to deal with ambiguities while still keeping the deterministic behavior.
See also
Deterministic context-free grammar
References
Alfred V. Aho, Stephen C. Johnson, Jeffrey D. Ullman (1975): Deterministic parsing of ambiguous grammars. Comm. ACM 18:8:441-452.
Mitchell Marcus (1978): A Theory of Syntactic Recognition for Natural Language. PhD Thesis, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology.
Parsing
|
https://en.wikipedia.org/wiki/Room%20modes
|
Room modes are the collection of resonances that exist in a room when the room is excited by an acoustic source such as a loudspeaker. Most rooms have their fundamental resonances in the 20 Hz to 200 Hz region, each frequency being related to one or more of the room's dimensions or a divisor thereof. These resonances affect the low-frequency low-mid-frequency response of a sound system in the room and are one of the biggest obstacles to accurate sound reproduction.
Mechanism of room resonances
The input of acoustic energy to the room at the modal frequencies and multiples thereof causes standing waves. The nodes and antinodes of these standing waves result in the loudness of the particular resonant frequency being different at different locations of the room. These standing waves can be considered a temporary storage of acoustic energy as they take a finite time to build up and a finite time to dissipate once the sound energy source has been removed.
Minimizing effect of room resonances
A room with generally hard surfaces will exhibit high-Q, sharply tuned resonances. Absorbent material can be added to the room to damp such resonances which work by more quickly dissipating the stored acoustic energy.
In order to be effective, a layer of porous, absorbent material has to be of the order of a quarter-wavelength thick if placed on a wall, which at low frequencies with their long wavelengths requires very thick absorbers. Absorption occurs through friction of the air motion
|
https://en.wikipedia.org/wiki/Vestibular%20ganglion
|
The vestibular ganglion (also called Scarpa's ganglion) is a ganglion situated within the internal auditory meatus that lodges cell bodies of first-order sensory neurons of the vestibular nerve. The superior division and inferior division of the vestibular nerve meet at the ganglion; henceforth, the fibres of second-order neurons of the vestibular nerve merge with those of the cochlear nerve (whose first-order neurons have already synapsed at the spiral ganglion) to proceed towards the CNS as a single unified vestibulocochlear nerve (cranial nerve VIII).
Anatomy
Structure
The ganglion contains the cell bodies of bipolar neurons whose peripheral processes form synaptic contact with hair cells of the vestibular sensory end organs. These include hair cells of the cristae ampullares of the semicircular duct, and the maculae of the utricle and saccule.
Development
At birth, it is already close to its final size.
Etymology
It is named for Antonio Scarpa.
References
External links
Diagram (in French)
Histology at wustl.edu
Vestibulocochlear nerve
Vestibular system
|
https://en.wikipedia.org/wiki/Salvage%20enzyme
|
Salvage enzymes are enzymes, nucleoside kinases, required during cell division to "salvage" nucleotides, present in body fluids, for the manufacture of DNA. They catalyze the phosphorylation of nucleosides to nucleoside - 5'-phosphates, that are further phosphorylated to triphosphates, that can be built into the growing DNA chain. The salvage enzymes are synthesized during the G1 phase in anticipation of DNA synthesis. After the cell division has been completed, the salvage enzymes, no longer required, are degraded. During interphase the cell derives its requirement of nucleoside-5'-phosphates by de novo synthesis, that leads directly to the 5'-monophosphate nucleotides.
Cell cycle
Enzymes
|
https://en.wikipedia.org/wiki/List%20of%20radio%20stations%20in%20Nuevo%20Le%C3%B3n
|
This is a list of radio stations in the state of Nuevo León, in Amplitude Modulated and Frequency Modulated bands.
Ciudad Anáhuac
Cerralvo
Doctor Arroyo
Galeana
Lampazos de Naranjo
Linares
Frequency Modulation
Montemorelos
Amplitude Modulation
Frequency Modulation
Monterrey Metropolitan Area
Amplitude Modulation
Frequency Modulation
Sabinas Hidalgo
Amplitude Modulation
Frequency Modulation
ND: No disponible
Defunct formats
Linares
Frequency Modulation
Monterrey
Amplitude Modulation
Frequency Modulation
Closed stations
Linares
Amplitude Modulation
Monterrey
Amplitude Modulation
Notes
All the amplitude modulated radio stations in Nuevo León that have acquired an FM frequency, means that they are going to change frequency.
References
Nuevo Leon
|
https://en.wikipedia.org/wiki/18-Methoxycoronaridine
|
18-Methoxycoronaridine (18-MC, or MM-110), also known as zolunicant, is a derivative of ibogaine invented in 1996 by the research team around the pharmacologist Stanley D. Glick from the Albany Medical College and the chemists Upul K. Bandarage and Martin E. Kuehne from the University of Vermont. In animal studies it has proved to be effective at reducing self-administration of morphine, cocaine, methamphetamine, nicotine and sucrose. It has also been shown to produce anorectic effects in obese rats, most likely due to the same actions on the reward system which underlie its anti-addictive effects against drug addiction.
18-MC was in the early stages of human testing by the California-based drug development company Savant HWP before being acquired by MindMed, a Canadian pharmaceutical company newly listed on the NASDAQ in April 2021. In 2002 the research team began raising funds for human trials, but were unable to secure the estimated $5 million needed. In 2010, Obiter Research, a chemical manufacturer in Champaign, Illinois, signed a patent license with Albany Medical College and the University of Vermont, allowing them the right to synthesize and market 18-MC and other congeners. In 2012 the National Institute on Drug Abuse gave a $6.5 million grant to Savant HWP for human trials. In 2017 it went into Phase-II trials in Brazil for treatment of Leishmaniasis at the Evandro Chagas Institute, but not for approval for use as a treatment for drug addiction. A phase 2a study o
|
https://en.wikipedia.org/wiki/Spatial%20cutoff%20frequency
|
In optics, spatial cutoff frequency is a precise way to quantify the smallest object resolvable by an optical system. Due to diffraction at the image plane, all optical systems act as low pass filters with a finite ability to resolve detail. If it were not for the effects of diffraction, a 2" aperture telescope could theoretically be used to read newspapers on a planet circling Alpha Centauri, over four light-years distant. Unfortunately, the wave nature of light will never permit this to happen.
The spatial cutoff frequency for a perfectly corrected incoherent optical system is given by
where is the wavelength expressed in millimeters and is the lens' focal ratio. As an example, a telescope having an objective and imaging at 0.55 micrometers has a spatial cutoff frequency of 303 cycles/millimeter. High-resolution black-and-white film is capable of resolving details on the film as small as 3 micrometers or smaller, thus its cutoff frequency is about 150 cycles/millimeter. So, the telescope's optical resolution is about twice that of high-resolution film, and a crisp, sharp picture would result (provided focus is perfect and atmospheric turbulence is at a minimum).
This formula gives the best-case resolution performance and is valid only for perfect optical systems. The presence of aberrations reduces image contrast and can effectively reduce the system spatial cutoff frequency if the image contrast falls below the ability of the imaging device to discern.
The c
|
https://en.wikipedia.org/wiki/5-HT2A%20receptor
|
{{DISPLAYTITLE:5-HT2A receptor}}
The 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor (GPCR). The 5-HT2A receptor is a cell surface receptor, but has several intracellular locations. 5-HT is short for 5-hydroxy-tryptamine or serotonin. This is the main excitatory receptor subtype among the GPCRs for serotonin, although 5-HT2A may also have an inhibitory effect on certain areas such as the visual cortex and the orbitofrontal cortex. This receptor was first noted for its importance as a target of serotonergic psychedelic drugs such as LSD and psilocybin mushrooms. Later it came back to prominence because it was also found to be mediating, at least partly, the action of many antipsychotic drugs, especially the atypical ones.
Downregulation of post-synaptic 5-HT2A receptor is an adaptive process provoked by chronic administration of selective serotonin reuptake inhibitors (SSRIs) and atypical antipsychotics. Suicidal and otherwise depressed patients have had more 5-HT2A receptors than normal patients. These findings suggest that post-synaptic 5-HT2A overdensity is involved in the pathogenesis of depression.
Paradoxical down-regulation of 5-HT2A receptors can be observed with several 5-HT2A antagonists. Thus, instead of tolerance, reverse-tolerance would be expected from 5-HT2A antagonists. However, there is at least one antagonist at this site which has been shown to up-regulate 5-HT2A receptor
|
https://en.wikipedia.org/wiki/False%20discovery%20rate
|
In statistics, the false discovery rate (FDR) is a method of conceptualizing the rate of type I errors in null hypothesis testing when conducting multiple comparisons. FDR-controlling procedures are designed to control the FDR, which is the expected proportion of "discoveries" (rejected null hypotheses) that are false (incorrect rejections of the null). Equivalently, the FDR is the expected ratio of the number of false positive classifications (false discoveries) to the total number of positive classifications (rejections of the null). The total number of rejections of the null include both the number of false positives (FP) and true positives (TP). Simply put, FDR = FP / (FP + TP). FDR-controlling procedures provide less stringent control of Type I errors compared to family-wise error rate (FWER) controlling procedures (such as the Bonferroni correction), which control the probability of at least one Type I error. Thus, FDR-controlling procedures have greater power, at the cost of increased numbers of Type I errors.
History
Technological motivations
The modern widespread use of the FDR is believed to stem from, and be motivated by, the development in technologies that allowed the collection and analysis of a large number of distinct variables in several individuals (e.g., the expression level of each of 10,000 different genes in 100 different persons). By the late 1980s and 1990s, the development of "high-throughput" sciences, such as genomics, allowed for rapid data acqu
|
https://en.wikipedia.org/wiki/Adams%20method
|
Adams method may refer to:
A method for the numerical solution of ordinary differential equations, also known as the linear multistep method
A method for apportionment of seats among states in the parliament, a kind of a highest-averages method
|
https://en.wikipedia.org/wiki/Ion%20transporter
|
In biology, a transporter is a transmembrane protein that moves ions (or other small molecules) across a biological membrane to accomplish many different biological functions including, cellular communication, maintaining homeostasis, energy production, etc. There are different types of transporters including, pumps, uniporters, antiporters, and symporters. Active transporters or ion pumps are transporters that convert energy from various sources—including adenosine triphosphate (ATP), sunlight, and other redox reactions—to potential energy by pumping an ion up its concentration gradient. This potential energy could then be used by secondary transporters, including ion carriers and ion channels, to drive vital cellular processes, such as ATP synthesis.
This page is focused mainly on ion transporters acting as pumps, but transporters can also function to move molecules through facilitated diffusion. Facilitated diffusion does not require ATP and allows molecules, that are unable to quickly diffuse across the membrane (passive diffusion), to diffuse down their concentration gradient through these protein transporters.
Ion transporters are essential for proper cell function and thus they are highly regulated by the cell and studied by researchers using a variety of methods. Some examples of cell regulations and research methods will be given.
Classification and disambiguation
Ion transporters are classified as a super family of transporters that contain 12 families of transp
|
https://en.wikipedia.org/wiki/Tantite
|
Tantite is a rare tantalum oxide mineral with formula: Ta2O5. Tantite forms transparent microscopic colorless triclinic - pedial crystals with an adamantine luster. It has a Mohs hardness of 7 and a high specific gravity of 8.45. Chemical analyses show minor inclusion (1.3%) of niobium oxide.
It was first described in 1983 for an occurrence in a pegmatite in the Kola peninsula, Russia. It has also been reported from a pegmatite complex in Florence County, Wisconsin. Associated mineral species include elbaite, lepidolite, spodumene, columbite-tantalite, wodginite, and microlite.
References
Wisconsin minerals Accessed March 31, 2006.
American Mineralogist data sheet PDF Accessed March 31, 2006.
Tantalum minerals
Oxide minerals
Triclinic minerals
Minerals in space group 1
Minerals described in 1983
|
https://en.wikipedia.org/wiki/Brauer%27s%20theorem%20on%20forms
|
There also is Brauer's theorem on induced characters.
In mathematics, Brauer's theorem, named for Richard Brauer, is a result on the representability of 0 by forms over certain fields in sufficiently many variables.
Statement of Brauer's theorem
Let K be a field such that for every integer r > 0 there exists an integer ψ(r) such that for n ≥ ψ(r) every equation
has a non-trivial (i.e. not all xi are equal to 0) solution in K.
Then, given homogeneous polynomials f1,...,fk of degrees r1,...,rk respectively with coefficients in K, for every set of positive integers r1,...,rk and every non-negative integer l, there exists a number ω(r1,...,rk,l) such that for n ≥ ω(r1,...,rk,l) there exists an l-dimensional affine subspace M of Kn (regarded as a vector space over K) satisfying
An application to the field of p-adic numbers
Letting K be the field of p-adic numbers in the theorem, the equation (*) is satisfied, since , b a natural number, is finite. Choosing k = 1, one obtains the following corollary:
A homogeneous equation f(x1,...,xn) = 0 of degree r in the field of p-adic numbers has a non-trivial solution if n is sufficiently large.
One can show that if n is sufficiently large according to the above corollary, then n is greater than r2. Indeed, Emil Artin conjectured that every homogeneous polynomial of degree r over Qp in more than r2 variables represents 0. This is obviously true for r = 1, and it is well known that the conjecture is true for r = 2 (see, for example, J.-
|
https://en.wikipedia.org/wiki/Classification%20theorem
|
In mathematics, a classification theorem answers the classification problem "What are the objects of a given type, up to some equivalence?". It gives a non-redundant enumeration: each object is equivalent to exactly one class.
A few issues related to classification are the following.
The equivalence problem is "given two objects, determine if they are equivalent".
A complete set of invariants, together with which invariants are solves the classification problem, and is often a step in solving it.
A (together with which invariants are realizable) solves both the classification problem and the equivalence problem.
A canonical form solves the classification problem, and is more data: it not only classifies every class, but provides a distinguished (canonical) element of each class.
There exist many classification theorems in mathematics, as described below.
Geometry
Classification of Euclidean plane isometries
Classification theorems of surfaces
Classification of two-dimensional closed manifolds
Enriques–Kodaira classification of algebraic surfaces (complex dimension two, real dimension four)
Nielsen–Thurston classification which characterizes homeomorphisms of a compact surface
Thurston's eight model geometries, and the geometrization conjecture
Berger classification
Classification of Riemannian symmetric spaces
Classification of 3-dimensional lens spaces
Classification of manifolds
Algebra
Classification of finite simple groups
Classification of Abelian gro
|
https://en.wikipedia.org/wiki/Prodynorphin
|
Prodynorphin, also known as proenkephalin B, is an opioid polypeptide hormone involved with chemical signal transduction and cell communication. The gene for prodynorphin is expressed in the endometrium and the striatum, and its gene map locus is 20pter-p12. Prodynorphin is a basic building-block of endorphins, the chemical messengers in the brain that appear most heavily involved in the anticipation and experience of pain and the formation of deep emotional bonds, and that are also critical in learning and memory.
The gene is thought to influence perception, as well as susceptibility to drug dependence, and is expressed more readily in human beings than in other primates.
Evolutionary implications
Most humans have multiple copies of the regulatory gene sequence for prodynorphin, which is virtually identical among all primates, whereas other primates have only a single copy. In addition, most Asian populations have two copies of the gene sequence for prodynorphin, whereas East Africas, Middle Easterners, and Europeans tend to have three repetitions.
The extent of regulatory gene disparities for prodynorphin, between human and primates, has gained the attention of scientists. There are very few genes known to be directly related to mankind's speciation from other great apes. According to computational biologist researcher Matthew W. Hahn of Indiana University, "this is the first documented instance of a neural gene that has had its regulation shaped by natural selection dur
|
https://en.wikipedia.org/wiki/The%20SMIC%20Private%20School
|
The SMIC Private School () is a private, coeducational K-12 school located in the Zhangjiang Science City of Shanghai, China. The school was founded by Semiconductor Manufacturing International Corporation (SMIC) in 2001 and by 2009 had over 1,450 students. 2017 marked its 16th anniversary. The School is accredited by the Western Association of Schools and Colleges and the East Asia Regional Council of Schools.
History
The school was initially founded to provide education for the families of employees of the SMIC company. Since 2004, the school has been open for public enrollment.
The school grew rapidly since its founding; the school had 75 students in the 1st year, and almost 700 students in its 4th year. The school had its first English track graduating class of 7 in 2006. In 2009, the school had over 1800 students from 22 different countries. The school is authorized and approved by The U.S. College Board as an official SAT and AP testing center.
The school provides two academic tracks: an international division that uses an American curriculum with a Chinese requirement and a Chinese track that is based on the local academic curriculum but with strong English emphasis. The SMIC Private School is accredited by the Pudong Board of Education and was awarded as an "Excellent Private Elementary School and Middle/High School in China" in December 2009.
In 2018, the school was at the center of a major food safety scandal in which its cafeteria contractor Eurest, a sub
|
https://en.wikipedia.org/wiki/Elementary%20divisors
|
In algebra, the elementary divisors of a module over a principal ideal domain (PID) occur in one form of the structure theorem for finitely generated modules over a principal ideal domain.
If is a PID and a finitely generated -module, then M is isomorphic to a finite sum of the form
where the are nonzero primary ideals.
The list of primary ideals is unique up to order (but a given ideal may be present more than once, so the list represents a multiset of primary ideals); the elements are unique only up to associatedness, and are called the elementary divisors. Note that in a PID, the nonzero primary ideals are powers of prime ideals, so the elementary divisors can be written as powers of irreducible elements. The nonnegative integer is called the free rank or Betti number of the module .
The module is determined up to isomorphism by specifying its free rank , and for class of associated irreducible elements and each positive integer the number of times that occurs among the elementary divisors. The elementary divisors can be obtained from the list of invariant factors of the module by decomposing each of them as far as possible into pairwise relatively prime (non-unit) factors, which will be powers of irreducible elements. This decomposition corresponds to maximally decomposing each submodule corresponding to an invariant factor by using the Chinese remainder theorem for R. Conversely, knowing the multiset of elementary divisors, the invariant factors can be fou
|
https://en.wikipedia.org/wiki/Geometric%20modeling
|
Geometric modeling is a branch of applied mathematics and computational geometry that studies methods and algorithms for the mathematical description of shapes.
The shapes studied in geometric modeling are mostly two- or three-dimensional (solid figures), although many of its tools and principles can be applied to sets of any finite dimension. Today most geometric modeling is done with computers and for computer-based applications. Two-dimensional models are important in computer typography and technical drawing. Three-dimensional models are central to computer-aided design and manufacturing (CAD/CAM), and widely used in many applied technical fields such as civil and mechanical engineering, architecture, geology and medical image processing.
Geometric models are usually distinguished from procedural and object-oriented models, which define the shape implicitly by an opaque algorithm that generates its appearance. They are also contrasted with digital images and volumetric models which represent the shape as a subset of a fine regular partition of space; and with fractal models that give an infinitely recursive definition of the shape. However, these distinctions are often blurred: for instance, a digital image can be interpreted as a collection of colored squares; and geometric shapes such as circles are defined by implicit mathematical equations. Also, a fractal model yields a parametric or implicit model when its recursive definition is truncated to a finite depth
|
https://en.wikipedia.org/wiki/Hilbert%27s%20theorem
|
Hilbert's theorem may refer to:
Hilbert's theorem (differential geometry), stating there exists no complete regular surface of constant negative gaussian curvature immersed in
Hilbert's Theorem 90, an important result on cyclic extensions of fields that leads to Kummer theory
Hilbert's basis theorem, in commutative algebra, stating every ideal in the ring of multivariate polynomials over a Noetherian ring is finitely generated
Hilbert's finiteness theorem, in invariant theory, stating that the ring of invariants of a reductive group is finitely generated
Hilbert's irreducibility theorem, in number theory, concerning irreducible polynomials
Hilbert's Nullstellensatz, the basis of algebraic geometry, establishing a fundamental relationship between geometry and algebra
Hilbert's syzygy theorem, a result of commutative algebra in connection with the syzygy problem of invariant theory
See also
List of things named after David Hilbert
|
https://en.wikipedia.org/wiki/Apollonius%27s%20theorem
|
In geometry, Apollonius's theorem is a theorem relating the length of a median of a triangle to the lengths of its sides.
It states that "the sum of the squares of any two sides of any triangle equals twice the square on half the third side, together with twice the square on the median bisecting the third side".
Specifically, in any triangle if is a median, then
It is a special case of Stewart's theorem. For an isosceles triangle with the median is perpendicular to and the theorem reduces to the Pythagorean theorem for triangle (or triangle ). From the fact that the diagonals of a parallelogram bisect each other, the theorem is equivalent to the parallelogram law.
The theorem is named for the ancient Greek mathematician Apollonius of Perga.
Proof
The theorem can be proved as a special case of Stewart's theorem, or can be proved using vectors (see parallelogram law). The following is an independent proof using the law of cosines.
Let the triangle have sides with a median drawn to side Let be the length of the segments of formed by the median, so is half of Let the angles formed between and be and where includes and includes Then is the supplement of and The law of cosines for and states that
Add the first and third equations to obtain
as required.
See also
References
External links
David B. Surowski: Advanced High-School Mathematics. p. 27
Euclidean geometry
Articles containing proofs
Theorems about triangles
|
https://en.wikipedia.org/wiki/List%20of%20Grand%20Slam%20boys%27%20singles%20champions
|
List of Boys' Singles Junior Grand Slam tournaments tennis champions.
Champions by year
Statistics
Most Grand Slam singles titles
Note: when a tie, the person to reach the mark first is listed first.
Grand Slam singles titles by country (since 1973)
Grand Slam achievements
Grand Slam
Players who held all four Grand Slam titles simultaneously (in a calendar year).
Career Grand Slam
Players who won all four Grand Slam titles over the course of their careers.
The event at which the Career Grand Slam was achieved is indicated in bold.
Multiple titles in a season
Three titles in a single season
Note: players who won 4 titles in a season are not included here.
Two titles in a single season
Note: players who won 3+ titles in a season are not included here.
Australian—French:
1952 Ken Rosewall
1961 John Newcombe
1962 John Newcombe (2)
1968 Phil Dent
1997 Daniel ElsnerAustralian—Wimbledon:
1989 Nicklas Kulti
1991 Thomas Enqvist
Australian—U.S.:
1995 Nicolas Kiefer
2000 Andy RoddickFrench—Wimbledon:
1958 Butch Buchholz
1963 Nicky Kalogeropoulos
1966 Vladimir Korotkov
1976 Heinz Günthardt
1978 Ivan Lendl
1979 Ramesh Krishnan
2018 Tseng Chun-hsin
French—U.S.:
1990 Andrea Gaudenzi
2002 Richard GasquetWimbledon—U.S.:
1973 Billy Martin
1974 Billy Martin (2)
1977 Van Winitsky
1982 Pat Cash
2008 Grigor Dimitrov
2012 Filip Peliwo
Surface Slam
Players who won Grand Slam titles on clay, grass and hard courts in a calendar year.
Channel Slam
Players who
|
https://en.wikipedia.org/wiki/Power%20module
|
A power module or power electronic module provides the physical containment for several power components, usually power semiconductor devices. These power semiconductors (so-called dies) are typically soldered or sintered on a power electronic substrate that carries the power semiconductors, provides electrical and thermal contact and electrical insulation where needed. Compared to discrete power semiconductors in plastic housings as TO-247 or TO-220, power packages provide a higher power density and are in many cases more reliable.
Module Topologies
Besides modules that contain a single power electronic switch (as MOSFET, IGBT, BJT, Thyristor, GTO or JFET) or diode, classical power modules contain multiple semiconductor dies that are connected to form an electrical circuit of a certain structure, called topology. Modules also contain other components such as ceramic capacitors to minimize switching voltage overshoots and NTC thermistors to monitor the module's substrate temperature. Examples of broadly available topologies implemented in modules are:
switch (MOSFET, IGBT), with antiparallel Diode;
bridge rectifier containing four (1-phase) or six (3-phase) diodes
half bridge (inverter leg, with two switches and their corresponding antiparallel diodes)
H-Bridge (four switches and the corresponding antiparallel diodes)
boost or power factor correction (one (or two) switches with one (or two) high frequency rectifying diodes)
ANPFC (power factor correction leg with two
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.