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https://en.wikipedia.org/wiki/Whitney%20immersion%20theorem | In differential topology, the Whitney immersion theorem (named after Hassler Whitney) states that for , any smooth -dimensional manifold (required also to be Hausdorff and second-countable) has a one-to-one immersion in Euclidean -space, and a (not necessarily one-to-one) immersion in -space. Similarly, every smooth -dimensional manifold can be immersed in the -dimensional sphere (this removes the constraint).
The weak version, for , is due to transversality (general position, dimension counting): two m-dimensional manifolds in intersect generically in a 0-dimensional space.
Further results
William S. Massey went on to prove that every n-dimensional manifold is cobordant to a manifold that immerses in where is the number of 1's that appear in the binary expansion of . In the same paper, Massey proved that for every n there is manifold (which happens to be a product of real projective spaces) that does not immerse in .
The conjecture that every n-manifold immerses in became known as the immersion conjecture. This conjecture was eventually solved in the affirmative by .
See also
Whitney embedding theorem
References
External links
(Exposition of Cohen's work)
Theorems in differential topology |
https://en.wikipedia.org/wiki/Buddhabrot | The Buddhabrot is the probability distribution over the trajectories of points that escape the Mandelbrot fractal. Its name reflects its pareidolic resemblance to classical depictions of Gautama Buddha, seated in a meditation pose with a forehead mark (tikka), a traditional oval crown (ushnisha), and ringlet of hair.
Discovery
The Buddhabrot rendering technique was discovered by Melinda Green, who later described it in a 1993 Usenet post to sci.fractals.
Previous researchers had come very close to finding the precise Buddhabrot technique. In 1988, Linas Vepstas relayed similar images to Cliff Pickover for inclusion in Pickover's then-forthcoming book Computers, Pattern, Chaos, and Beauty. This led directly to the discovery of Pickover stalks. Noel Griffin also implemented this idea in the 1993 "Mandelcloud" option in the Fractint renderer. However, these researchers did not filter out non-escaping trajectories required to produce the ghostly forms reminiscent of Hindu art. The inverse, "Anti-Buddhabrot" filter produces images similar to no filtering.
Green first named this pattern Ganesh, since an Indian co-worker "instantly recognized it as the god 'Ganesha' which is the one with the head of an elephant." The name Buddhabrot was coined later by Lori Gardi.
Rendering method
Mathematically, the Mandelbrot set consists of the set of points in the complex plane for which the iteratively defined sequence
does tend to infinity as goes to infinity for .
The Buddhabrot i |
https://en.wikipedia.org/wiki/Friedmann%20equations | The Friedmann equations are a set of equations in physical cosmology that govern the expansion of space in homogeneous and isotropic models of the universe within the context of general relativity. They were first derived by Alexander Friedmann in 1922 from Einstein's field equations of gravitation for the Friedmann–Lemaître–Robertson–Walker metric and a perfect fluid with a given mass density and pressure . The equations for negative spatial curvature were given by Friedmann in 1924.
Assumptions
The Friedmann equations start with the simplifying assumption that the universe is spatially homogeneous and isotropic, that is, the cosmological principle; empirically, this is justified on scales larger than the order of 100 Mpc. The cosmological principle implies that the metric of the universe must be of the form
where is a three-dimensional metric that must be one of (a) flat space, (b) a sphere of constant positive curvature or (c) a hyperbolic space with constant negative curvature. This metric is called Friedmann–Lemaître–Robertson–Walker (FLRW) metric. The parameter discussed below takes the value 0, 1, −1, or the Gaussian curvature, in these three cases respectively. It is this fact that allows us to sensibly speak of a "scale factor" .
Einstein's equations now relate the evolution of this scale factor to the pressure and energy of the matter in the universe. From FLRW metric we compute Christoffel symbols, then the Ricci tensor. With the stress–energy tensor for a |
https://en.wikipedia.org/wiki/Exponential%20backoff | Exponential backoff is an algorithm that uses feedback to multiplicatively decrease the rate of some process, in order to gradually find an acceptable rate. These algorithms find usage in a wide range of systems and processes, with radio networks and computer networks being particularly notable.
Exponential backoff algorithm
An exponential backoff algorithm is a form of closed-loop control system that reduces the rate of a controlled process in response to adverse events. For example, if a smartphone app fails to connect to its server, it might try again 1 second later, then if it fails again, 2 seconds later, then 4, etc. Each time the pause is multiplied by a fixed amount (in this case 2). In this case, the adverse event is failing to connect to the server. Other examples of adverse events include collisions of network traffic, an error response from a service, or an explicit request to reduce the rate (i.e. "back off").
The rate reduction can be modelled as an exponential function:
or
Here, is the time delay applied between actions, is the multiplicative factor or "base", is the number of adverse events observed, and is the frequency (or rate) of the process (i.e. number of actions per unit of time). The value of is incremented each time an adverse event is observed, leading to an exponential rise in delay and, therefore, an inversely proportionate rate. An exponential backoff algorithm where is referred to as a binary exponential backoff algorithm.
When the ra |
https://en.wikipedia.org/wiki/Lami%27s%20theorem | In physics, Lami's theorem is an equation relating the magnitudes of three coplanar, concurrent and non-collinear vectors, which keeps an object in static equilibrium, with the angles directly opposite to the corresponding vectors. According to the theorem,
where A, B and C are the magnitudes of the three coplanar, concurrent and non-collinear vectors, , which keep the object in static equilibrium, and α, β and γ are the angles directly opposite to the vectors.
Lami's theorem is applied in static analysis of mechanical and structural systems. The theorem is named after Bernard Lamy.
Proof
As the vectors must balance , hence by making all the vectors touch its tip and tail the result is a triangle with sides A, B, C and angles By the law of sines then
Then by applying that for any angle , , and the result is
See also
Mechanical equilibrium
Parallelogram of force
Tutte embedding
References
Further reading
R.K. Bansal (2005). "A Textbook of Engineering Mechanics". Laxmi Publications. p. 4. .
I.S. Gujral (2008). "Engineering Mechanics". Firewall Media. p. 10.
Eponymous theorems of physics
Statics |
https://en.wikipedia.org/wiki/Endonuclease | In molecular biology, endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain (namely DNA or RNA). Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (without regard to sequence), while many, typically called restriction endonucleases or restriction enzymes, cleave only at very specific nucleotide sequences. Endonucleases differ from exonucleases, which cleave the ends of recognition sequences instead of the middle (endo) portion. Some enzymes known as "exo-endonucleases", however, are not limited to either nuclease function, displaying qualities that are both endo- and exo-like. Evidence suggests that endonuclease activity experiences a lag compared to exonuclease activity.
Restriction enzymes are endonucleases from eubacteria and archaea that recognize a specific DNA sequence. The nucleotide sequence recognized for cleavage by a restriction enzyme is called the restriction site. Typically, a restriction site will be a palindromic sequence about four to six nucleotides long. Most restriction endonucleases cleave the DNA strand unevenly, leaving complementary single-stranded ends. These ends can reconnect through hybridization and are termed "sticky ends". Once paired, the phosphodiester bonds of the fragments can be joined by DNA ligase. There are hundreds of restriction endonucleases known, each attacking a different restriction site. The DNA fragments cleaved by the same endonuclease can be joined regardless of the or |
https://en.wikipedia.org/wiki/Cathy%20Downs | Catherine N. Downs (March 3, 1926 – December 8, 1976) was an American film actress.
Biography
Downs was born in Port Jefferson, New York. She was the daughter of James Nelson Downs and Edna Elizabeth Newman.
A model for the Walter Thornton Agency, she was brought to Hollywood in 1944 by a 20th Century Fox talent scout. The studio initially used her as a model, giving her limited opportunities to act.
She began her film career with small roles in State Fair (1945) and The Dolly Sisters (1945). In 1946, she played the title role in My Darling Clementine and Clifton Webb's unfaithful wife in The Dark Corner. Following the success of My Darling Clementine, Downs was cast in a prison drama For You I Die (1947), an Abbott and Costello comedy The Noose Hangs High, and several Western films. In 1947, Downs was dropped by Fox for unknown reasons, and was never employed by another major studio. In 1949, she participated in a later famous Life magazine photo layout, in which she posed with other up-and-coming actresses, Marilyn Monroe, Lois Maxwell, Suzanne Dalbert, Laurette Luez, Jane Nigh, and Enrica Soma. By the early 1950s, she was appearing in low-budget films, including some science-fiction (sci-fi) stories, including the 1958 sci-fi/fantasy Missile to the Moon. She appeared in a television episode of The Lone Ranger in 1952.
She portrayed Ann Howe in the syndicated TV series The Joe Palooka Story (1954). In 1959, she portrayed "Amelia Roberts" in the episode "Marked Deck" (S |
https://en.wikipedia.org/wiki/Range%20fractionation | Range fractionation is a term used in biology to describe the way by which a group of sensory neurons are able to encode varying magnitudes of a stimulus. Sense organs are usually composed of many sensory receptors measuring the same property. These sensory receptors show a limited degree of precision due to an upper limit in firing rate. If the receptors are endowed with distinct transfer functions in such a way that the points of highest sensitivity are scattered along the axis of the quality being measured, the precision of the sense organ as a whole can be increased.
The basis of the idea of range fractionation is that each stimulus (for example, touch) has a range of intensities that can be sensed (light-touch to deep/hard-touch). For an organism to be able to sense a range of stimulus intensities, sensory neurons are tuned to fractions of the entire range. Collectively, the pattern of activity among the sensory neurons is how the organism can identify specific stimulus parameters. This was shown for proprioceptive neurons in the locust leg, proprioceptive neurons in the stick insect, Johnston's Organ neurons in Drosophila, and in auditory-sensing neurons in crickets.
Range fraction is similar to the labeled line theory in that they both describe a phenomenon by which sensory neurons divide the task of encoding a range of stimulus intensities. However the difference lies within the downstream synaptic partners. Labeled line theory describes fully segregated channels p |
https://en.wikipedia.org/wiki/Fluidization | Fluidization (or fluidisation) is a process similar to liquefaction whereby a granular material is converted from a static solid-like state to a dynamic fluid-like state. This process occurs when a fluid (liquid or gas) is passed up through the granular material.
When a gas flow is introduced through the bottom of a bed of solid particles, it will move upwards through the bed via the empty spaces between the particles. At low gas velocities, aerodynamic drag on each particle is also low, and thus the bed remains in a fixed state. Increasing the velocity, the aerodynamic drag forces will begin to counteract the gravitational forces, causing the bed to expand in volume as the particles move away from each other. Further increasing the velocity, it will reach a critical value at which the upward drag forces will exactly equal the downward gravitational forces, causing the particles to become suspended within the fluid. At this critical value, the bed is said to be fluidized and will exhibit fluidic behavior. By further increasing gas velocity, the bulk density of the bed will continue to decrease, and its fluidization becomes more intense until the particles no longer form a bed and are "conveyed" upwards by the gas flow.
When fluidized, a bed of solid particles will behave as a fluid, like a liquid or gas. Like water in a bucket: the bed will conform to the volume of the chamber, its surface remaining perpendicular to gravity; objects with a lower density than the bed |
https://en.wikipedia.org/wiki/Ranked%20list%20of%20Paraguayan%20departments | Population figures from the 2021 statistics by the INE, the National Statistics Institute.
By population
By area
By density
This is a list of regions of Paraguay by Human Development Index as of 2017.
References
Paraguay
Human Development Index
List
departments |
https://en.wikipedia.org/wiki/PKC | PKC may refer to:
Paroxysmal kinesogenic choreoathetosis, a neurological disorder
Protein kinase C, a family of enzymes
Public-key cryptography, a cryptographic system using pairs of keys
PKC (conference)
Petropavlovsk-Kamchatsky Airport or Yelizovo Airport, Kamchatka Krai, Russia (IATA code PKC)
PKC Group, a Finnish company
Perth and Kinross Council, a local authority in Scotland |
https://en.wikipedia.org/wiki/Edna%20May%20Oliver | Edna May Oliver (born Edna May Nutter, November 9, 1883 – November 9, 1942) was an American stage and film actress. During the 1930s, she was one of the better-known character actresses in American films, often playing tart-tongued spinsters.
Career
Born in Malden, Massachusetts, the daughter of Ida May and Charles Edward Nutter, Oliver quit school at age 14 to pursue a stage career.
She achieved her first success in 1917 on Broadway in Jerome Kern's musical comedy Oh, Boy!, playing the hero's comically dour Aunt Penelope. In 1925, Oliver appeared on Broadway in The Cradle Snatchers, costarring Mary Boland, Gene Raymond, and Humphrey Bogart. Oliver's most notable stage appearance was as Parthy, wife of Cap'n Andy Hawks, in the original 1927 stage production of the musical Show Boat. She reprised her role in the 1932 Broadway revival, but turned down the chance to play Parthy in the 1936 film version to play the Nurse in that year's film version of Romeo and Juliet.
Her film debut was in 1923 in Wife in Name Only. She continued to appear in films until Lydia in 1941. She first gained major notice in films for her appearances in several comedies starring the team of Wheeler & Woolsey, including Half Shot at Sunrise, her first film under her RKO Radio Pictures contract in 1930. Usually in featured parts, she starred in ten films, including Fanny Foley Herself (1931) and Ladies of the Jury (1932). She played wealthy, domineering Aunt March in the 1933 version of Little Women. |
https://en.wikipedia.org/wiki/Cauliflower%20ear | Cauliflower ear is an irreversible condition that occurs when the external portion of the ear is hit and develops a blood clot or other collection of fluid under the perichondrium. This separates the cartilage from the overlying perichondrium that supplies its nutrients, causing it to die and resulting in the formation of fibrous tissue in the overlying skin. As a result, the outer ear becomes permanently swollen and deformed, resembling a cauliflower, hence the name.
The condition is common in martial arts such as Brazilian jiu-jitsu, wrestling, boxing, kickboxing, judo, sumo, or mixed martial arts, and in full-contact sports such as rugby league or rugby union.
Presentation
People presenting with possible auricular hematoma often have additional injuries (for example, head/neck lacerations) due to the frequently traumatic causes of auricular hematoma. The ear itself is often tense, fluctuant, and tender with throbbing pain. However, because of potentially more remarkable injuries often associated with auricular hematoma, auricular hematoma can easily be overlooked without directed attention.
Causes
The most common cause of cauliflower ear is blunt trauma to the ear leading to a hematoma which, if left untreated, eventually heals to give the distinct appearance of cauliflower ear. Most commonly coming from participating in grappling and combat sports such as Brazilian jiu-jitsu and mixed martial arts. The structure of the ear is supported by a cartilaginous scaffold consi |
https://en.wikipedia.org/wiki/Complement%20receptor%201 | Complement receptor type 1 (CR1) also known as C3b/C4b receptor or CD35 (cluster of differentiation 35) is a protein that in humans is encoded by the CR1 gene.
This gene is a member of the regulators of complement activation (RCA) family and is located in the 'cluster RCA' region of chromosome 1. The gene encodes a monomeric single-pass type I membrane glycoprotein found on erythrocytes, leukocytes, glomerular podocytes, hyalocytes, and splenic follicular dendritic cells. The Knops blood group system is a system of antigens located on this protein. The protein mediates cellular binding to particles and immune complexes that have activated complement. Decreases in expression of this protein and/or mutations in its gene have been associated with gallbladder carcinomas, mesangiocapillary glomerulonephritis, systemic lupus erythematosus and sarcoidosis. Mutations in this gene have also been associated with a reduction in Plasmodium falciparum rosetting, conferring protection against severe malaria. Alternate allele-specific splice variants, encoding different isoforms, have been characterized. Additional allele specific isoforms, including a secreted form, have been described but have not been fully characterized.
In primates, CR1 serves as the main system for processing and clearance of complement opsonized immune complexes. It has been shown that CR1 can act as a negative regulator of the complement cascade, mediate immune adherence and phagocytosis and inhibit both the clas |
https://en.wikipedia.org/wiki/Man%20or%20boy%20test | The man or boy test was proposed by computer scientist Donald Knuth as a means of evaluating implementations of the ALGOL 60 programming language. The aim of the test was to distinguish compilers that correctly implemented "recursion and non-local references" from those that did not.
Knuth's example
In ALGOL 60:
begin
real procedure A(k, x1, x2, x3, x4, x5);
value k; integer k;
real x1, x2, x3, x4, x5;
begin
real procedure B;
begin k := k - 1;
B := A := A(k, B, x1, x2, x3, x4)
end;
if k ≤ 0 then A := x4 + x5 else B
end
outreal(1, A(10, 1, -1, -1, 1, 0))
end
This creates a tree of B call frames that refer to each other and to the containing A call frames, each of which has its own copy of k that changes every time the associated B is called. Trying to work it through on paper is probably fruitless, but for k = 10, the correct answer is −67, despite the fact that in the original article Knuth conjectured it to be −121. Even modern machines quickly run out of stack space for larger values of k, which are tabulated below ().
Explanation
There are three Algol features used in this program that can be difficult to implement properly in a compiler:
Nested function definitions: Since B is being defined in the local context of A, the body of B has access to symbols that are local to A — most notably k, which it modifies, but also x1, x2, x3, x4, and x5. This is straightforward in the Algol descendant Pascal, but not possible in the other major |
https://en.wikipedia.org/wiki/TPK%20algorithm | The TPK algorithm is a simple program introduced by Donald Knuth and Luis Trabb Pardo to illustrate the evolution of computer programming languages. In their 1977 work "The Early Development of Programming Languages", Trabb Pardo and Knuth introduced a small program that involved arrays, indexing, mathematical functions, subroutines, I/O, conditionals and iteration. They then wrote implementations of the algorithm in several early programming languages to show how such concepts were expressed.
To explain the name "TPK", the authors referred to Grimm's law (which concerns the consonants 't', 'p', and 'k'), the sounds in the word "typical", and their own initials (Trabb Pardo and Knuth). In a talk based on the paper, Knuth said:
The algorithm
Knuth describes it as follows:
In pseudocode:
ask for 11 numbers to be read into a sequence S
reverse sequence S
for each item in sequence S
call a function to do an operation
if result overflows
alert user
else
print result
The algorithm reads eleven numbers from an input device, stores them in an array, and then processes them in reverse order, applying a user-defined function to each value and reporting either the value of the function or a message to the effect that the value has exceeded some threshold.
Implementations
Implementations in the original paper
In the original paper, which covered "roughly the first decade" of the development of high-level programming languages (from 1945 up to 1 |
https://en.wikipedia.org/wiki/ALGO | ALGO is an algebraic programming language developed for the Bendix G-15 computer.
ALGO was one of several programming languages inspired by the Preliminary Report on the International Algorithmic Language written in Zürich in 1958. This report underwent several modifications before becoming the Revised Report on which most ALGOL implementations are based. As a result, ALGO and other early ALGOL-related languages have a very different syntax from ALGOL 60.
Example
Here is the Trabb Pardo – Knuth algorithm in ALGO:
TITLE TRABB PARDO-KNUTH ALGORITHM
SUBSCript I,J
DATA A(11)
FORMAt FI(2DT), FLARGE(3D)
PROCEDURE F(T=Z)
BEGIN
Z=SQRT(ABS(T))+5*T^3
END
FOR I=0(1)10
A[I]=KEYBD
FOR J=0(1)10 BEGIN
I=J-10
F(A[I]=Y)
PRINT(FI)=I
IF Y > 400
GO TO LARGE
PRINT(FL)=Y
GO TO NEXT
LARGE: PRINT(FLARGE)=999
NEXT: CARR(1) END
2END
Remarks
See also
ALGOL 58
ALGOL 60
References
External links
ALGO manual (PDF)
ALGOL 58 dialect |
https://en.wikipedia.org/wiki/CD36 | CD36 (cluster of differentiation 36), also known as platelet glycoprotein 4, fatty acid translocase (FAT), scavenger receptor class B member 3 (SCARB3), and glycoproteins 88 (GP88), IIIb (GPIIIB), or IV (GPIV) is a protein that in humans is encoded by the CD36 gene. The CD36 antigen is an integral membrane protein found on the surface of many cell types in vertebrate animals. It imports fatty acids inside cells and is a member of the class B scavenger receptor family of cell surface proteins. CD36 binds many ligands including collagen, thrombospondin, erythrocytes parasitized with Plasmodium falciparum, oxidized low density lipoprotein, native lipoproteins, oxidized phospholipids, and long-chain fatty acids.
Work in genetically modified rodents suggest a role for CD36 in fatty acid metabolism, heart disease, taste, and dietary fat processing in the intestine. It may be involved in glucose intolerance, atherosclerosis, arterial hypertension, diabetes, cardiomyopathy, Alzheimer's disease and various cancers, mostly of epithelial origin (breast, prostate, ovary, and colon) and also for hepatic carcinoma and gliomas.
Structure
Primary
In humans, rats and mice, CD36 consists of 472 amino acids with a predicted molecular weight of approximately 53,000 Da. However, CD36 is extensively glycosylated and has an apparent molecular weight of 88,000 Da as determined by SDS polyacrylamide gel electrophoresis.
Tertiary
Using Kyte-Doolittle analysis, the amino acid sequence of CD36 p |
https://en.wikipedia.org/wiki/Rotary%20converter | A rotary converter is a type of electrical machine which acts as a mechanical rectifier, inverter or frequency converter.
Rotary converters were used to convert alternating current (AC) to direct current (DC), or DC to AC power, before the advent of chemical or solid state power rectification and inverting. They were commonly used to provide DC power for commercial, industrial and railway electrification from an AC power source.
Principles of operation
The rotary converter can be thought of as a motor-generator, where the two machines share a single rotating armature and set of field coils. The basic construction of the rotary converter consists of a DC generator (dynamo) with a set of slip rings tapped into its rotor windings at evenly spaced intervals. When a dynamo is spun the electric currents in its rotor windings alternate as it rotates in the magnetic field of the stationary field windings. This alternating current is rectified by means of a commutator, which allows direct current to be extracted from the rotor. This principle is taken advantage of by energizing the same rotor windings with AC power, which causes the machine to act as a synchronous AC motor. The rotation of the energized coils excites the stationary field windings producing part of the direct current. The other part is alternating current from the slip rings, which is directly rectified into DC by the commutator. This makes the rotary converter a hybrid dynamo and mechanical rectifier. When used in |
https://en.wikipedia.org/wiki/Tower%20%28disambiguation%29 | A tower is a tall human-made structure.
Tower may also refer to:
Types of towers
Air traffic control tower
Bell tower
Cell tower, a cellular telephone communications site
Clock tower
Computer tower
Conning tower
Cooling tower
Drop tower, an amusement park ride
Fire lookout tower
Fortified tower
Interlocking tower or control cabin, directs railroad traffic
Lattice tower or truss tower
Martello tower, a small defensive fort
Office tower
Peel tower, a small fortified keep or tower house
Radio tower
Siege tower or breaching tower
Telecommunications tower (disambiguation)
Television tower
Tower houses in the Balkans, tower houses built in the Balkans
Transmission tower, used for electric power transmission
Watchtower, a type fortification used in many parts of the world
Water tower
Places
Geography
Tower (ward), ward of the City of London, England
Tower, County Cork, Ireland
Tower, Michigan, United States
Tower, Minnesota, United States
Tower Branch, a stream in Pennsylvania, United States
Buildings with the name
Tower of London, also known as "The Tower"
Towers (Boston University), a dormitory at Boston University
Trump Tower, a mixed use commercial and residential building in New York City
People
Tower (surname), also Towers (surname)
Arts, entertainment, media and sports
Fictional entities
Tower (Code Lyoko), element of virtual world in animated TV series
Tower (comics), a Marvel Comics character
Music
Tower (album), an album by the F |
https://en.wikipedia.org/wiki/Weight%20gain | Weight gain is an increase in body weight. This can involve an increase in muscle mass, fat deposits, excess fluids such as water or other factors. Weight gain can be a symptom of a serious medical condition.
Description
Weight gain occurs when more energy (as calories from food and beverage consumption) is gained than the energy expended by life activities, including normal physiological processes and physical exercise.
If enough weight is gained due to increased body fat deposits, one may become overweight or obese, generally defined as having more body fat (adipose tissue) than is considered good for health. The Body Mass Index (BMI) measures body weight in proportion to height, and defines optimal, insufficient, and excessive weight based on the ratio.
Having excess adipose tissue (fat) is a common condition, especially where food supplies are plentiful and lifestyles are sedentary. Overweight and obesity may increase the risk of several diseases, such as diabetes, heart disease, and some cancers, and may lead to short- and long-term health problems during pregnancy. Rates of obesity worldwide tripled from 1975 to 2016 to involve some 1.8 billion people and 39% of the world adult population.
A commonly asserted "rule" (the Wishnofsky Rule, aka Wishnofsky's Rule) for weight gain or loss, is based on the research of Max Wishnofsky (December 17, 1899 – August 2, 1965), a Russian-born physician who had a medical practice in Brooklyn, New York. The Wishnofsky Rule states |
https://en.wikipedia.org/wiki/Hyperreflexia | Hyperreflexia is overactive or overresponsive bodily reflexes. Examples of this include twitching and spastic tendencies, which indicate disease of the upper motor neurons and the lessening or loss of control ordinarily exerted by higher brain centers of lower neural pathways (disinhibition).
Spinal-cord injury is the most common cause of hyperreflexia (see "Autonomic dysreflexia"). Standard stimuli, such as the filling of the bladder, can cause excessive responses from the nervous system; the causes are not known.
Hyperreflexia also has many other causes, including the side effects of drugs and stimulants; hyperthyroidism; electrolyte imbalance; serotonin syndrome; severe brain trauma; multiple sclerosis; Reye syndrome; and preeclampsia.
Treatment depends on the cause of the hyperreflexia. If drugs cause it, treatment may require that they not be used.
Recovery from hyperreflexia can occur several hours to several months after a spinal-cord injury; the phase of recovery is likely to occur in stages rather than on a continuum. The late stage is between two weeks and several months. Patients with a severe spinal-cord injury (SCI) mainly present with a later stage of recovery because during the early stages they present with spinal shock. Reflex and motor recovery can sometimes occur simultaneously.
See also
Hyporeflexia
References
External links
NIH/Medline
Archives of Physical Medicine and Rehabilitation
Symptoms and signs: Nervous system |
https://en.wikipedia.org/wiki/Germicidal%20lamp | A germicidal lamp (also known as disinfection lamp or sterilizer lamp) is an electric light that produces ultraviolet C (UVC) light. This short-wave ultraviolet light disrupts DNA base pairing, causing formation of pyrimidine dimers, and leads to the inactivation of bacteria, viruses, and protozoans. It can also be used to produce ozone for water disinfection. They are used in ultraviolet germicidal irradiation (UVGI).
There are four common types available:
Low-pressure mercury lamps
High-pressure mercury lamps
Excimer lamps
LEDs
Low-pressure mercury lamps
Low-pressure mercury lamps are very similar to a fluorescent lamp, with a wavelength of 253.7 nm (1182.5 THz).
The most common form of germicidal lamp looks similar to an ordinary fluorescent lamp but the tube contains no fluorescent phosphor. In addition, rather than being made of ordinary borosilicate glass, the tube is made of fused quartz or vycor 7913 glass. These two changes combine to allow the 253.7 nm ultraviolet light produced by the mercury arc to pass out of the lamp unmodified (whereas, in common fluorescent lamps, it causes the phosphor to fluoresce, producing visible light). Germicidal lamps still produce a small amount of visible light due to other mercury radiation bands.
An older design looks like an incandescent lamp but with the envelope containing a few droplets of mercury. In this design, the incandescent filament heats the mercury, producing a vapor which eventually allows an arc to be struck |
https://en.wikipedia.org/wiki/Lymphoblast |
A lymphoblast is a modified naive lymphocyte with altered cell morphology. It occurs when the lymphocyte is activated by an antigen and increased in volume by nucleus and cytoplasm growth as well as new mRNA and protein synthesis. The lymphoblast then starts dividing two to four times every 24 hours for three to five days, with a single lymphoblast making approximately 1000 clones of its original naive lymphocyte, with each clone sharing the originally unique antigen specificity. Finally the dividing cells differentiate into effector cells, known as plasma cells (for B cells), cytotoxic T cells, and helper T cells.
Lymphoblasts can also refer to immature cells which typically differentiate to form mature lymphocytes. Normally lymphoblasts are found in the bone marrow, but in acute lymphoblastic leukemia (ALL), lymphoblasts proliferate uncontrollably and are found in large numbers in the peripheral blood.
The size is between 10 and 20 μm.
Although commonly lymphoblast refers to a precursor cell in the maturation of leukocytes, the usage of this term is sometimes inconsistent. The Chronic Lymphocytic Leukemia Research Consortium defines a lymphoblast as "A lymphocyte that has become larger after being stimulated by an antigen. Lymphoblasts look like immature lymphocytes, and were once thought to be precursor cells." Commonly, when speaking about leukemia, "blast" is used as an abbreviation for lymphoblasts.
Lymphoblasts can be distinguished microscopically from myeloblasts |
https://en.wikipedia.org/wiki/2003%20in%20British%20music | This is a summary of 2003 in music in the United Kingdom.
Events
6 January – The annual Park Lane Group Young Artists festival of contemporary music opens with two concerts in the Purcell Room at the Southbank Centre, London. The first concert, given by the Gallimaufry Ensemble, included the premiere of a new wind quintet by 23-year-old Benjamin Wallfisch; the second concert featured solo bass clarinettist Sarah Watts, who premiered Marc Yeats' Vox for solo bass clarinet and Michael Smetanin's Ladder of Escape for bass clarinet with prerecorded ensemble of six bass and two contrabass clarinets.
10 January - Following an investigation by The International Federation of the Phonographic Industry and London detectives, police raids in the UK and the Netherlands recover 500 original Beatles studio tapes, recorded during the Let It Be sessions. Five people are arrested. The tapes have been used for bootleg releases for years.
13 January - The Who guitarist Pete Townshend is arrested on suspicion of possessing and making indecent images of children and of incitement to distribute them. Townshend claims in a statement that he did not download any such images and accessed Web sites advertising child pornography because he was researching material for his autobiography, which will include passages about his abusive childhood.
18 January - A two-day festival of the music of Mark-Anthony Turnage is given at the Barbican Centre, London, with three world premieres and chamber concerts by |
https://en.wikipedia.org/wiki/Tophus | A tophus (Latin: "stone", : tophi) is a deposit of monosodium urate crystals, in people with longstanding high levels of uric acid (urate) in the blood, a condition known as hyperuricemia. Tophi are pathognomonic for the disease gout. Most people with tophi have had previous attacks of acute arthritis, eventually leading to the formation of tophi. Chronic tophaceous gout is known as Harrison Syndrome.
Tophi form in the joints, cartilage, bones, and other places throughout the body. Sometimes, tophi break through the skin and appear as white or yellowish-white, chalky nodules. Without treatment, tophi may develop on average about ten years after the onset of gout, although their first appearance can range from three to forty-two years. The development of gouty tophi can also limit joint function and cause bone destruction, leading to noticeable disabilities, especially when gout cannot successfully be treated. When uric acid levels and gout symptoms cannot be controlled with standard gout medicines that decrease the production of uric acid (e.g., allopurinol, febuxostat) or increase uric acid elimination from the body through the kidneys (e.g., probenecid), this can be referred to as refractory chronic gout (RCG). They are more apt to appear early in the course of the disease in people who are older.
Although less common, tophi can also form in the kidneys and nasal cartilage.
Pathophysiology
It appears that monosodium urate crystals trigger a distinct physiological NETos |
https://en.wikipedia.org/wiki/Power%20series%20solution%20of%20differential%20equations | In mathematics, the power series method is used to seek a power series solution to certain differential equations. In general, such a solution assumes a power series with unknown coefficients, then substitutes that solution into the differential equation to find a recurrence relation for the coefficients.
Method
Consider the second-order linear differential equation
Suppose is nonzero for all . Then we can divide throughout to obtain
Suppose further that and are analytic functions.
The power series method calls for the construction of a power series solution
If is zero for some , then the Frobenius method, a variation on this method, is suited to deal with so called "singular points". The method works analogously for higher order equations as well as for systems.
Example usage
Let us look at the Hermite differential equation,
We can try to construct a series solution
Substituting these in the differential equation
Making a shift on the first sum
If this series is a solution, then all these coefficients must be zero, so for both k=0 and k>0:
We can rearrange this to get a recurrence relation for .
Now, we have
We can determine A0 and A1 if there are initial conditions, i.e. if we have an initial value problem.
So we have
and the series solution is
which we can break up into the sum of two linearly independent series solutions:
which can be further simplified by the use of hypergeometric series.
A simpler way using Taylor series
A much simpler way of so |
https://en.wikipedia.org/wiki/Thue%20equation | In mathematics, a Thue equation is a Diophantine equation of the form
ƒ(x,y) = r,
where ƒ is an irreducible bivariate form of degree at least 3 over the rational numbers, and r is a nonzero rational number. It is named after Axel Thue, who in 1909 proved that a Thue equation can have only finitely many solutions in integers x and y, a result known as Thue's theorem,
The Thue equation is solvable effectively: there is an explicit bound on the solutions x, y of the form where constants C1 and C2 depend only on the form ƒ. A stronger result holds: if K is the field generated by the roots of ƒ, then the equation has only finitely many solutions with x and y integers of K, and again these may be effectively determined.
Finiteness of solutions and diophantine approximation
Thue's original proof that the equation named in his honour has finitely many solutions is through the proof of what is now known as Thue's theorem: it asserts that for any algebraic number having degree and for any there exists only finitely many co-prime integers with such that . Applying this theorem allows one to almost immediately deduce the finiteness of solutions. However, Thue's proof, as well as subsequent improvements by Siegel, Dyson, and Roth were all ineffective.
Solution algorithm
Finding all solutions to a Thue equation can be achieved by a practical algorithm, which has been implemented in the following computer algebra systems:
in PARI/GP as functions thueinit() and thue().
in Magm |
https://en.wikipedia.org/wiki/Admissible%20rule | In logic, a rule of inference is admissible in a formal system if the set of theorems of the system does not change when that rule is added to the existing rules of the system. In other words, every formula that can be derived using that rule is already derivable without that rule, so, in a sense, it is redundant. The concept of an admissible rule was introduced by Paul Lorenzen (1955).
Definitions
Admissibility has been systematically studied only in the case of structural (i.e. substitution-closed) rules in propositional non-classical logics, which we will describe next.
Let a set of basic propositional connectives be fixed (for instance, in the case of superintuitionistic logics, or in the case of monomodal logics). Well-formed formulas are built freely using these connectives from a countably infinite set of propositional variables p0, p1, .... A substitution σ is a function from formulas to formulas that commutes with applications of the connectives, i.e.,
for every connective f, and formulas A1, ... , An. (We may also apply substitutions to sets Γ of formulas, making ) A Tarski-style consequence relation is a relation between sets of formulas, and formulas, such that
for all formulas A, B, and sets of formulas Γ, Δ. A consequence relation such that
for all substitutions σ is called structural. (Note that the term "structural" as used here and below is unrelated to the notion of structural rules in sequent calculi.) A structural consequence relation is called a |
https://en.wikipedia.org/wiki/Steiner%20point | A Steiner point (named after Jakob Steiner) may refer to:
Steiner point (computational geometry), a point added in solving a geometric optimization problem to make its solution better
Steiner point (triangle), a certain point on the circumcircle of a given triangle
One of 20 points associated with a given set of six points on a conic; see
See also
Steiner tree problem, an algorithmic problem of finding extra Steiner points to add to a point set to reduce the cost of connecting the points
The median of three vertices in a median graph, the solution to the Steiner tree problem for those three vertices
The Fermat point of a triangle, the solution to the Steiner tree problem for the three vertices of the triangle |
https://en.wikipedia.org/wiki/Allantois | The allantois ( ; : allantoides or allantoises) is a hollow sac-like structure filled with clear fluid that forms part of a developing amniote's conceptus (which consists of all embryonic and extraembryonic tissues). It helps the embryo exchange gases and handle liquid waste.
The allantois, along with the amnion, chorion, and yolk sac (other extraembryonic membranes), identify humans and other mammals, birds, and reptiles as amniotes. These extraembryonic membranes that form the embryo have aided amniotes in the transition from aquatic to terrestrial environments. Fish and amphibians are anamniotes, and lack the allantois. In mammals the extraembryonic membranes are known as the fetal membranes.
Function
This sac-like structure, whose name is the Neo-Latin equivalent of "sausage" (from Greek ἀλλαντοειδής allantoeidḗs, in reference to its shape when first formed) is primarily involved in nutrition and excretion, and is webbed with blood vessels. The function of the allantois is to collect liquid waste from the embryo, as well as to exchange gases used by the embryo.
In mammals
In mammals excluding egg-laying monotremes, the allantois is one of the fetal membranes, and is part of and forms an axis for the development of the umbilical cord.
While the function of the allantois remains conserved, there is a divergence in the characteristics of the allantois among mammalian species. Structural variations of the allantois include differences in size and shape.
In mammals, the e |
https://en.wikipedia.org/wiki/Kyushu%20Q1W | The Kyūshū Q1W Tōkai (東海 "Eastern Sea") was a land-based anti-submarine patrol bomber aircraft developed for the Imperial Japanese Navy in World War II. The Allied reporting name was Lorna. Although similar in appearance to the German Junkers Ju 88 medium bomber, the Q1W was a much smaller aircraft with significantly different design details.
Design and development
The Imperial Japanese Navy ordered development of the Kyūshū Q1W as the Navy Experimental 17-Shi Patrol Plane in September 1942, and the first test flight took place in September 1943. It entered service in January 1945. The Q1W carried two low-power engines, allowing for long periods of low-speed flight.
In same period Kyūshū built the K11W1 Shiragiku, a bomber training plane (also used in Kamikaze strikes) and the Q3W1 Nankai (South Sea), a specialized antisubmarine version of the K11W. The latter was of all-wood construction and was destroyed during a landing accident on its first flight.
Another specific anti-submarine airplane was the Mitsubishi Q2M1 "Taiyō" (which was derived from Mitsubishi Ki-67 Hiryū "Peggy" Torpedo-bomber), but this did not progress beyond the preliminary design stage.
Variants
Q1W1 : one prototype.
Q1W1 Tokai Model 11: main production model.
Q1W2 Tokai Model 21: version with tail surfaces in wood, built in small numbers.
Q1W1-K Tokai-Ren (Eastern Sea-Trainer): trainer with capacity for four, all-wood construction. One prototype built.
Specifications (Q1W1)
See also
Footnotes
|
https://en.wikipedia.org/wiki/Expectiminimax | The expectiminimax algorithm is a variation of the minimax algorithm, for use in artificial intelligence systems that play two-player zero-sum games, such as backgammon, in which the outcome depends on a combination of the player's skill and chance elements such as dice rolls. In addition to "min" and "max" nodes of the traditional minimax tree, this variant has "chance" ("move by nature") nodes, which take the expected value of a random event occurring. In game theory terms, an expectiminimax tree is the game tree of an extensive-form game of perfect, but incomplete information.
In the traditional minimax method, the levels of the tree alternate from max to min until the depth limit of the tree has been reached. In an expectiminimax tree, the "chance" nodes are interleaved with the max and min nodes. Instead of taking the max or min of the utility values of their children, chance nodes take a weighted average, with the weight being the probability that child is reached.
The interleaving depends on the game. Each "turn" of the game is evaluated as a "max" node (representing the AI player's turn), a "min" node (representing a potentially-optimal opponent's turn), or a "chance" node (representing a random effect or player).
For example, consider a game in which each round consists of a single die throw, and then decisions made by first the AI player, and then another intelligent opponent. The order of nodes in this game would alternate between "chance", "max" and then "min". |
https://en.wikipedia.org/wiki/AFLC | AFLC may refer to:
Air Force Logistics Command
American Football League of China
Antiferroelectric liquid crystal
Association of Free Lutheran Congregations |
https://en.wikipedia.org/wiki/Pyrosequencing | Pyrosequencing is a method of DNA sequencing (determining the order of nucleotides in DNA) based on the "sequencing by synthesis" principle, in which the sequencing is performed by detecting the nucleotide incorporated by a DNA polymerase. Pyrosequencing relies on light detection based on a chain reaction when pyrophosphate is released. Hence, the name pyrosequencing.
The principle of pyrosequencing was first described in 1993 by, Bertil Pettersson, Mathias Uhlen and Pål Nyren by combining the solid phase sequencing method using streptavidin coated magnetic beads with recombinant DNA polymerase lacking 3´to 5´exonuclease activity (proof-reading) and luminescence detection using the firefly luciferase enzyme. A mixture of three enzymes (DNA polymerase, ATP sulfurylase and firefly luciferase) and a nucleotide (dNTP) are added to single stranded DNA to be sequenced and the incorporation of nucleotide is followed by measuring the light emitted. The intensity of the light determines if 0, 1 or more nucleotides have been incorporated, thus showing how many complementary nucleotides are present on the template strand. The nucleotide mixture is removed before the next nucleotide mixture is added. This process is repeated with each of the four nucleotides until the DNA sequence of the single stranded template is determined.
A second solution-based method for pyrosequencing was described in 1998 by Mostafa Ronaghi, Mathias Uhlen and Pål Nyren. In this alternative method, an addition |
https://en.wikipedia.org/wiki/The%20Cold%20Equations | "The Cold Equations" is a science fiction short story by American writer Tom Godwin, first published in Astounding Magazine in August 1954. In 1970, the Science Fiction Writers of America selected it as one of the best science-fiction short stories published before 1965, and it was therefore included in The Science Fiction Hall of Fame, Volume One, 1929–1964. The story has been widely anthologized and dramatized.
Summary
The story takes place entirely aboard an Emergency Dispatch Ship () headed for the frontier planet Woden with a load of desperately needed medical supplies. The pilot discovers a stowaway: an eighteen-year-old woman.
By law, all stowaways are to be jettisoned because vessels carry only the fuel absolutely necessary to land safely at their destination. The young woman wanted merely to visit her brother on the remote planet and was unaware of the law. When she saw the "UNAUTHORIZED PERSONNEL KEEP OUT!" sign while she was sneaking onboard the , she thought that at most she would have to pay a fine if she was caught.
The pilot explains that her weight sabotages the mission by exceeding the ship's fuel limit. The subsequent crash would kill both of them and then doom the colonists awaiting the medical supplies.
After contacting her brother in the last moments of her life, the woman willingly climbs into the airlock and is ejected into space.
Development
The story was shaped by Astounding Science Fiction editor John W. Campbell, who sent "Cold Equations" bac |
https://en.wikipedia.org/wiki/Menger%27s%20theorem | In the mathematical discipline of graph theory, Menger's theorem says that in a finite graph, the size of a minimum cut set is equal to the maximum number of disjoint paths that can be found between any pair of vertices.
Proved by Karl Menger in 1927, it characterizes the connectivity of a graph.
It is generalized by the max-flow min-cut theorem, which is a weighted, edge version, and which in turn is a special case of the strong duality theorem for linear programs.
Edge connectivity
The edge-connectivity version of Menger's theorem is as follows:
Let G be a finite undirected graph and x and y two distinct vertices. Then the size of the minimum edge cut for x and y (the minimum number of edges whose removal disconnects x and y) is equal to the maximum number of pairwise edge-independent paths from x to y.
Extended to all pairs: a graph is k-edge-connected (it remains connected after removing fewer than k edges) if and only if every pair of vertices has k edge-disjoint paths in between.
Vertex connectivity
The vertex-connectivity statement of Menger's theorem is as follows:
Let G be a finite undirected graph and x and y two nonadjacent vertices. Then the size of the minimum vertex cut for x and y (the minimum number of vertices, distinct from x and y, whose removal disconnects x and y) is equal to the maximum number of pairwise internally vertex-disjoint paths from x to y.
Extended to all pairs: a graph is k-vertex-connected (it has more than k vertices and it remains co |
https://en.wikipedia.org/wiki/Helmholtz%20equation | In mathematics, the Helmholtz equation is the eigenvalue problem for the Laplace operator. It corresponds to the linear partial differential equation
where is the Laplace operator, is the eigenvalue, and is the (eigen)function. When the equation is applied to waves, is known as the wave number. The Helmholtz equation has a variety of applications in physics and other sciences, including the wave equation, the diffusion equation, and the Schrödinger equation for a free particle.
Motivation and uses
The Helmholtz equation often arises in the study of physical problems involving partial differential equations (PDEs) in both space and time. The Helmholtz equation, which represents a time-independent form of the wave equation, results from applying the technique of separation of variables to reduce the complexity of the analysis.
For example, consider the wave equation
Separation of variables begins by assuming that the wave function is in fact separable:
Substituting this form into the wave equation and then simplifying, we obtain the following equation:
Notice that the expression on the left side depends only on , whereas the right expression depends only on . As a result, this equation is valid in the general case if and only if both sides of the equation are equal to the same constant value. This argument is key in the technique of solving linear partial differential equations by separation of variables. From this observation, we obtain two equations, one for , |
https://en.wikipedia.org/wiki/Tetanic%20stimulation | In neurobiology, a tetanic stimulation consists of a high-frequency sequence of individual stimulations of a neuron. It is associated with potentiation.
High-frequency stimulation causes an increase in release called post-tetanic potentiation (Kandel 2003). This presynaptic event is caused by calcium influx. Calcium-protein interactions then produce a change in vesicle exocytosis. The result of these changes is to make the postsynaptic cell more likely to fire an action potential.
Tetanic stimulation is used in medicine to detect a non-depolarizing block or a depolarizing block on the neuromuscular junction. Lower elicitations of tetanic stimulation in aged muscles were shown to be caused by lower levels of anaerobic energy provision in skeletal muscles.
See also
Hebbian theory
References
Neurophysiologists
de:Tetanisierung |
https://en.wikipedia.org/wiki/Mixed-signal%20integrated%20circuit | A mixed-signal integrated circuit is any integrated circuit that has both analog circuits and digital circuits on a single semiconductor die. Their usage has grown dramatically with the increased use of cell phones, telecommunications, portable electronics, and automobiles with electronics and digital sensors.
Overview
Integrated circuits (ICs) are generally classified as digital (e.g. a microprocessor) or analog (e.g. an operational amplifier). Mixed-signal ICs contain both digital and analog circuitry on the same chip, and sometimes embedded software. Mixed-signal ICs process both analog and digital signals together. For example, an analog-to-digital converter (ADC) is a typical mixed-signal circuit.
Mixed-signal ICs are often used to convert analog signals to digital signals so that digital devices can process them. For example, mixed-signal ICs are essential components for FM tuners in digital products such as media players, which have digital amplifiers. Any analog signal can be digitized using a very basic ADC, and the smallest and most energy efficient of these are mixed-signal ICs.
Mixed-signal ICs are more difficult to design and manufacture than analog-only or digital-only integrated circuits. For example, an efficient mixed-signal IC may have its digital and analog components share a common power supply. However, analog and digital components have very different power needs and consumption characteristics, which makes this a non-trivial goal in chip design.
Mi |
https://en.wikipedia.org/wiki/Virial%20expansion | The virial expansion is a model of thermodynamic equations of state. This model expresses the pressure P of a gas in local equilibrium as a power series of the density. This equation may be represented in terms of the compressibility factor, , as
This equation was first proposed by Kamerlingh Onnes. The terms A, B, and C represent the virial coefficients. The leading coefficient, A, is defined as the constant value of 1, which enforces that the equation reduces to the ideal gas expression as the gas density approaches zero.
Second and third virial coefficients
The second, , and third, , virial coefficients have been studied extensively and tabulated for many fluids for more than a century. Two of the most extensive compilations are in the books by Dymond. and NIST Thermo Data Engine Database and its Web Thermo Tables. Tables of second and third virial coefficients of many fluids are included in these compilations.
The second and third virial coefficients as functions of temperature are shown in the following figure for argon. Reduced temperature and reduced virial coefficients, scaled by respective critical properties, are all dimensionless. Notice in the figure that the second virial coefficient decreases monotonically as temperature is lowered. However, the third virial coefficient has a bell shape. It increases as temperature is lowered to the critical temperature, then it passes through a peak and decreases rapidly to zero as temperature is lowered from the critica |
https://en.wikipedia.org/wiki/Petechia | A petechia (; : petechiae) is a small red or purple spot (≤4 mm in diameter) that can appear on the skin, conjunctiva, retina, and mucous membranes which is caused by haemorrhage of capillaries. The word is derived from Italian , 'freckle,' of obscure origin. It refers to one of the three descriptive types of hematoma differentiated by size, the other two being ecchymosis (>1cm in diameter) and purpura (4-10mm in diameter). The term is always used in the plural (petechiae), since a single petechia is seldom noticed or significant.
Causes
Physical trauma
The most common cause of petechiae is through physical trauma such as a hard bout of coughing, holding breath, vomiting, or crying, which can result in facial petechiae, especially around the eyes. Excessive scratching and friction, especially on thin and poorly circulated parts of the body may also cause petechiae. Such instances are generally considered harmless and usually disappear within a few days, but depending on severity and frequency may be indicative of an underlying medical condition.
Constriction, asphyxiation – petechiae, especially in the eyes, may also occur when excessive pressure is applied to tissue (e.g., when a tourniquet is applied to an extremity or with excessive coughing or vomiting).
Sunburn, childbirth, weightlifting
Gua Sha, a Chinese treatment that scrapes the skin
High-G training
Hickey
Asphyxiation
Choking game
Oral sex
Non-infectious conditions
Vitamin C deficiency, scurvy
Vitamin |
https://en.wikipedia.org/wiki/Transcendental%20number%20theory | Transcendental number theory is a branch of number theory that investigates transcendental numbers (numbers that are not solutions of any polynomial equation with rational coefficients), in both qualitative and quantitative ways.
Transcendence
The fundamental theorem of algebra tells us that if we have a non-constant polynomial with rational coefficients (or equivalently, by clearing denominators, with integer coefficients) then that polynomial will have a root in the complex numbers. That is, for any non-constant polynomial with rational coefficients there will be a complex number such that . Transcendence theory is concerned with the converse question: given a complex number , is there a polynomial with rational coefficients such that If no such polynomial exists then the number is called transcendental.
More generally the theory deals with algebraic independence of numbers. A set of numbers {α1, α2, …, αn} is called algebraically independent over a field K if there is no non-zero polynomial P in n variables with coefficients in K such that P(α1, α2, …, αn) = 0. So working out if a given number is transcendental is really a special case of algebraic independence where n = 1 and the field K is the field of rational numbers.
A related notion is whether there is a closed-form expression for a number, including exponentials and logarithms as well as algebraic operations. There are various definitions of "closed-form", and questions about closed-form can often be red |
https://en.wikipedia.org/wiki/DNA%20sequencing | DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery.
Knowledge of DNA sequences has become indispensable for basic biological research, DNA Genographic Projects and in numerous applied fields such as medical diagnosis, biotechnology, forensic biology, virology and biological systematics. Comparing healthy and mutated DNA sequences can diagnose different diseases including various cancers, characterize antibody repertoire, and can be used to guide patient treatment. Having a quick way to sequence DNA allows for faster and more individualized medical care to be administered, and for more organisms to be identified and cataloged.
The rapid speed of sequencing attained with modern DNA sequencing technology has been instrumental in the sequencing of complete DNA sequences, or genomes, of numerous types and species of life, including the human genome and other complete DNA sequences of many animal, plant, and microbial species.
The first DNA sequences were obtained in the early 1970s by academic researchers using laborious methods based on two-dimensional chromatography. Following the development of fluorescence-based sequencing methods with a DNA sequencer, DNA sequencing has become |
https://en.wikipedia.org/wiki/Hypoxanthine-guanine%20phosphoribosyltransferase | Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is an enzyme encoded in humans by the HPRT1 gene.
HGPRT is a transferase that catalyzes conversion of hypoxanthine to inosine monophosphate and guanine to guanosine monophosphate. This reaction transfers the 5-phosphoribosyl group from 5-phosphoribosyl 1-pyrophosphate (PRPP) to the purine. HGPRT plays a central role in the generation of purine nucleotides through the purine salvage pathway.
Function
HGPRT catalyzes the following reactions:
HGPRTase functions primarily to salvage purines from degraded DNA to reintroduce into purine synthetic pathways. In this role, it catalyzes the reaction between guanine and phosphoribosyl pyrophosphate (PRPP) to form GMP, or between hypoxanthine and phosphoribosyl pyrophosphate (PRPP) to form inosine monophosphate.
Substrates and inhibitors
Comparative homology modelling of this enzyme in L. donovani suggest that among all of the computationally screened compounds, pentamidine, 1,3-dinitroadamantane, acyclovir and analogs of acyclovir had higher binding affinities than the real substrate (guanosine monophosphate).
The in silico and in-vitro correlation of these compounds were test in Leishmania HGPRT and validates the result.
Role in disease
Mutations in the gene lead to hyperuricemia. At least 67 disease-causing mutations in this gene have been discovered:
Some men have partial (up to 20% less activity of the enzyme) HGPRT deficiency that causes high levels of uric acid in |
https://en.wikipedia.org/wiki/Isotype | Isotype can refer to:
Isotype (biology), a duplicate of the holotype of a species
Isotype (crystallography), a synonym for isomorph
Isotype (immunology), an antibody class according to its Fc region
Isotype (picture language), a method of showing social, technological, biological and historical connections in pictorial form
Isotype (song), 2017 song by Orchestral Manoeuvres in the Dark
See also
Isotope (disambiguation)
Isoform |
https://en.wikipedia.org/wiki/Prithudaka | Chaturveda Prithudaka Swami () was an Indian mathematician best known for his work on solving equations. He also wrote an important commentary on Brahmagupta's work.
References
Sources
9th-century Indian mathematicians |
https://en.wikipedia.org/wiki/Antisense%20RNA | Antisense RNA (asRNA), also referred to as antisense transcript, natural antisense transcript (NAT) or antisense oligonucleotide, is a single stranded RNA that is complementary to a protein coding messenger RNA (mRNA) with which it hybridizes, and thereby blocks its translation into protein. The asRNAs (which occur naturally) have been found in both prokaryotes and eukaryotes, and can be classified into short (<200 nucleotides) and long (>200 nucleotides) non-coding RNAs (ncRNAs). The primary function of asRNA is regulating gene expression. asRNAs may also be produced synthetically and have found wide spread use as research tools for gene knockdown. They may also have therapeutic applications.
Discovery and history in drug development
Some of the earliest asRNAs were discovered while investigating functional proteins. An example was micF asRNA. While characterizing the outer membrane porin in E.coli, some of the promoter clones observed were capable of repressing the expression of other membrane porin such as . The region responsible for this repression function was found to be a 300 base-pair locus upstream of the promoter. This 300 base-pair region is 70% homologous in sequence with the 5' end of the mRNA and thus the transcript of this 300 base pair locus was complementary to the mRNA. Later on, this transcript, denoted micF, was found to be an asRNA of and capable of downregulating the expression of under stress by forming a duplex with the mRNA. This induces t |
https://en.wikipedia.org/wiki/Protein%20skimmer | A protein skimmer or foam fractionator is a device used to remove organic compounds such as food and waste particles from water. It is most commonly used in commercial applications like municipal water treatment facilities, public aquariums, and aquaculture facilities. Smaller protein skimmers are also used for filtration of home saltwater aquariums and even freshwater aquariums and ponds.
Function
Protein skimming removes certain organic compounds, including proteins and amino acids found in food particles and fish waste, by using the polarity of the protein itself. Due to their intrinsic charge, water-borne proteins are either repelled or attracted by the air/water interface and these molecules can be described as hydrophobic (such as fats or oils) or hydrophilic (such as salt, sugar, ammonia, most amino acids, and most inorganic compounds). However, some larger organic molecules can have both hydrophobic and hydrophilic portions. These molecules are called amphipathic or amphiphilic. Commercial protein skimmers work by generating a large air/water interface, specifically by injecting large numbers of bubbles into the water column. In general, the smaller the bubbles the more effective the protein skimming is because the surface area of small bubbles occupying the same volume is much greater than the same volume of larger bubbles. Large numbers of small bubbles present an enormous air/water interface for hydrophobic organic molecules and amphipathic organic molecules to c |
https://en.wikipedia.org/wiki/Gun%20%28cellular%20automaton%29 | In a cellular automaton, a gun is a pattern with a main part that repeats periodically, like an oscillator, and that also periodically emits spaceships. There are then two periods that may be considered: the period of the spaceship output, and the period of the gun itself, which is necessarily a multiple of the spaceship output's period. A gun whose period is larger than the period of the output is a pseudoperiod gun.
In the Game of Life, for every p greater than or equal to 14, it is possible to construct a glider gun in which the gliders are emitted with period p.
Since guns continually emit spaceships, the existence of guns in Life means that initial patterns with finite numbers of cells can eventually lead to configurations with limitless numbers of cells, something that John Conway himself originally conjectured to be impossible. However, according to Conway's later testimony, this conjecture was explicitly intended to encourage someone to disprove it – i.e., Conway hoped that infinite-growth patterns did exist.
Bill Gosper discovered the first glider gun in 1970, earning $50 from Conway. The discovery of the glider gun eventually led to the proof that Conway's Game of Life could function as a Turing machine. For many years this glider gun was the smallest one known in Life, although other rules had smaller guns.
References
Cellular automaton patterns |
https://en.wikipedia.org/wiki/Boule%20%28crystal%29 | A boule is a single-crystal ingot produced by synthetic means.
A boule of silicon is the starting material for most of the integrated circuits used today. In the semiconductor industry synthetic boules can be made by a number of methods, such as the Bridgman technique and the Czochralski process, which result in a cylindrical rod of material.
In the Czochralski process a seed crystal is required to create a larger crystal, or ingot. This seed crystal is dipped into the pure molten silicon and slowly extracted. The molten silicon grows on the seed crystal in a crystalline fashion. As the seed is extracted the silicon solidifies and eventually a large, cylindrical boule is produced.
A semiconductor crystal boule is normally cut into circular wafers using an inside hole diamond saw or diamond wire saw, and each wafer is lapped and polished to provide substrates suitable for the fabrication of semiconductor devices on its surface.
The process is also used to create sapphires, which are used for substrates in the production of blue and white LEDs, optical windows in special applications and as the protective covers for watches.
References
Crystals
Semiconductor growth |
https://en.wikipedia.org/wiki/Seed%20crystal | A seed crystal is a small piece of single crystal or polycrystal material from which a large crystal of typically the same material is grown in a laboratory. Used to replicate material, the use of seed crystal to promote growth avoids the otherwise slow randomness of natural crystal growth and allows manufacture on a scale suitable for industry.
Crystal enlargement
The large crystal can be grown by dipping the seed into a supersaturated solution, into molten material that is then cooled, or by growth on the seed face by passing vapor of the material to be grown over it.
Theory
The theory behind this effect is thought to derive from the physical intermolecular interaction that occurs between compounds in a supersaturated solution (or possibly vapor). In solution, liberated (soluble) molecules (solute) are free to move about in random flow. This random flow permits for the possibility of two or more molecular compounds to interact. This interaction can potentiate intermolecular forces between the separate molecules and form a basis for a crystal lattice. The placement of a seed crystal into solution allows the recrystallization process to expedite by eliminating the need for random molecular collision or interaction. By introducing an already pre-formed basis of the target crystal to act upon, the intermolecular interactions are formed much more easily or readily, than relying on random flow. Often, this phase transition from solute in a solution to a crystal lattice will be |
https://en.wikipedia.org/wiki/Zehista | Zehista is a village in the municipality of Pirna in the Sächsische Schweiz-Osterzgebirge district of Saxony, Germany. It was incorporated into Pirna in 1930. The place was mentioned for the first time in 1355. It lies in the valley of the river Seidewitz, 2.5 km southwest of Pirna town centre.
References
Pirna
1350s establishments in the Holy Roman Empire
1355 establishments in Europe
Populated places established in the 1350s |
https://en.wikipedia.org/wiki/Krietzschwitz | Krietzschwitz is a village in the municipality of Pirna, in Saxony, Germany. It was incorporated into Pirna in 1974. The place was mentioned for the first time in 1359. It is situated on Bundesstraße 172, 5 km southeast of Pirna town centre.
References
Pirna
Populated places in Saxon Switzerland |
https://en.wikipedia.org/wiki/Mesochronous%20network | A mesochronous network is a telecommunications network in which the clocks run with the same frequency but unknown phases. Compare synchronous network.
See also
Synchronization in telecommunications
Isochronous signal
Plesiochronous system
Asynchronous system
Network architecture
Synchronization |
https://en.wikipedia.org/wiki/Lacteal | A lacteal is a lymphatic capillary that absorbs dietary fats in the villi of the small intestine.
Triglycerides are emulsified by bile and hydrolyzed by the enzyme lipase, resulting in a mixture of fatty acids, di- and monoglycerides. These then pass from the intestinal lumen into the enterocyte, where they are re-esterified to form triglyceride. The triglyceride is then combined with phospholipids, cholesterol ester, and apolipoprotein B48 to form chylomicrons. These chylomicrons then pass into the lacteals, forming a milky substance known as chyle. The lacteals merge to form larger lymphatic vessels that transport the chyle to the thoracic duct where it is emptied into the bloodstream at the subclavian vein.
At this point, the fats are in the bloodstream in the form of chylomicrons. Once in the blood, chylomicrons are subject to delipidation by lipoprotein lipase. Eventually, enough lipid has been lost and additional apolipoproteins gained, that the resulting particle (now referred to as a chylomicron remnant) can be taken up by the liver. From the liver, the fat released from chylomicron remnants can be re-exported to the blood as the triglyceride component of very low-density lipoproteins. Very low-density lipoproteins are also subject to delipidation by vascular lipoprotein lipase, and deliver fats to tissues throughout the body. In particular, the released fatty acids can be stored in adipose cells as triglycerides. As triglycerides are lost from very low-density lip |
https://en.wikipedia.org/wiki/Mara%20River | The Mara River is a river in that begins in Narok County (Kenya) and in ends in Mara Region (Tanzania), and lies across the migration path of ungulates in the Maasai Mara/Serengeti ecosystem.
The River's flow
The Mara River basin covers a surface of 13,504 km2, of which approximately 65% is located in Kenya and 35% in Tanzania. From its sources in the Kenyan highlands, the river flows for about 395 km and originates from the Mau Escarpment and drains into Lake Victoria. The basin can be roughly divided into four land use and/or administrative units.
The Mara's regions
The Mau Escarpment: The Mara River originates from the Napuiyapi swamp (2932 m), with the main perennial tributaries being the Amala and the Nyangores, which drain from the western Mau Escarpment. This part of the basin supports besides forests, both small-scale agriculture (less than 10 acres) and medium-size farms (often tea farms up to 40 acres).
The Kenyan Rangelands: In this area, the Amala and Nyangores rivers flow out of the Mau Escarpment and converge to form the Mara River. The river then meanders further through open savannah grasslands that is mostly governed by Maasai group ranches and used as pasture for livestock and for both small — and large-scale agriculture (more than 40 acres). The basins of four important tributaries to the Mara (the Talek, Engare, Sand and Engito rivers) are also located in this area, together with some upland areas like the Loita Hills.
The Protected areas: Eventually |
https://en.wikipedia.org/wiki/Robert%20Nalbandyan | Robert M. Nalbandyan (, 1937–2002) was an Armenian chemist, the co-discoverer of photosynthetic protein plantacyanin, a pioneer in the field of free radicals, and a noted and prolific writer on various subjects in the field of chemistry.
Born in Yerevan, Armenia and educated at Moscow State University in Moscow, Russia, Nalbandyan lived and worked in Yerevan for most of his life, where he also headed a laboratory and lectured. He was recognized as one of Soviet Union's most prominent chemists, and in his research collaborated with fellow chemists in the USSR, US, Europe, and Australia. When the Armenian Soviet Socialist Republic struck for independence in 1989, Nalbandyan became a prominent critic of the nationalist movement, which he felt was foolhardy and was merely agitating the people for political gain. The energy shortage, economic woes, and virtual blockade experienced after independence seemed to justify his concerns. In 1996 he left the country and emigrated to the United States.
Primarily known in the scientific community for his research work with proteins, Nalbandyan was also recognized among his fellow scientists as a progressive thinker in other fields of chemistry, including neurochemistry.
References
1937 births
2002 deaths
Scientists from Yerevan
Moscow State University alumni
Armenian emigrants to the United States
Armenian chemists |
https://en.wikipedia.org/wiki/ProBoards | ProBoards is a free, remotely hosted message board service that facilitates online discussions by allowing people to create their own online communities.
Ownership and service statistics
ProBoards was founded by Patrick Clinger, who wrote the ProBoards software. Prior to launching ProBoards, Clinger had run HostedScripts, a company aimed at creating free web widgets.
The service hosts over 3,000,000 internet forums, which in turn have approximately 22,800,000 users worldwide. Currently, all ProBoards forums combined receive a total of over 600 million pageviews per month, making ProBoards one of the largest websites on the Internet.
However, according to TechCrunch writer Anthony Ha, those numbers have seemingly dropped as of 2014. In an interview, founder/owner Patrick Clinger stated "ProBoards has been used to create 3.5 million forums", but about 1.2 million of them are still active (i.e. resulting in the occasional page view). In October 2021, ProBoards was purchased by internet company VerticalScope Holdings.
Software history
Proboards is coded in Perl, a popular programming language with web developers. Previously, due to the remotely hosted nature of the service, users could not modify the software directly as with some forum systems, but some customisation was possible through the use of CSS or JavaScript codes. With the release of v.5, however, ProBoards gives Administrators and certain other members access to the HTML and CSS of the webpage, for easier coding pu |
https://en.wikipedia.org/wiki/Mesogen | A mesogen is a compound that displays liquid crystal properties. Mesogens can be described as disordered solids or ordered liquids because they arise from a unique state of matter that exhibits both solid- and liquid-like properties called the liquid crystalline state. This liquid crystalline state (LC) is called the mesophase and occurs between the crystalline solid (Cr) state and the isotropic liquid (Iso) state at distinct temperature ranges.
The liquid crystal properties arise because mesogenic compounds are composed of rigid and flexible parts, which help characterize the order and mobility of its structure. The rigid components align mesogen moieties in one direction and have distinctive shapes that are typically found in the form of rod or disk shapes. The flexible segments provide mesogens with mobility because they are usually made up of alkyl chains, which hinder crystallization to a certain degree. The combination of rigid and flexible chains induce structural alignment and fluidity between liquid crystal moieties.
In doing so, varying degrees of order and mobility within mesogens results in different types of liquid crystal phases, Figure 1. The nematic phase (N) is the least ordered and most fluid liquid crystalline state or mesophase that is based on the rigid core of mesogen moieties. The nematic phase leads to long range orientational order and short range positional order of mesogens. The smectic (Sm) and columnar (Col) phases are more ordered and less flu |
https://en.wikipedia.org/wiki/List%20of%20Wazamono | Wazamono is a classification of Japanese swords and swordsmiths used in Japan to identify historic blades of exceptional quality. According to the first edition of Kaiho Kenjaku (懐宝剣尺) published in 1797, There are 163 Wazamono swords in total, grouped into four categories based on their quality. Twelve swords are classified as Saijō Ō Wazamono (Supreme Grade), twenty-one swords are classified as Ō Wazamono (Excellent), fifty swords are classified as Yoki (Ryō) Wazamono (Very Good), and eighty swords are classified as Wazamono (Good).
This rating is based on a book compiled by Yamada Asaemon V (山田浅右衛門吉睦), an official sword cutting ability examiner and executioner of the Tokugawa shogunate, and is an authoritative index of cutting ability of Japanese swords. The list of ratings concerning swordsmithing differs between Kaiho Kenjaku (懐宝剣尺) published in 1797 and the reprinted edition published in 1805, and the major revised edition of Kokon Kajibiko (古今鍛冶備考) published in 1830. Add up the number of sword smiths in each edition: Saijo Ō Wazamono 15, 'Ō Wazamono 21, Yoki Wazamono 58, Wazamono 93, lower 3 grade mixed 65.
The list of swordsmiths described below is the swordsmiths described in the first edition of Kaiho.
Twelve Saijō Ō Wazamono
There are 12 blades that hold the rank of Saiju Ō Wazamono (Supreme Grade). This is the highest classification of Wazamono. In the reprinted edition in 1805 and the major revised edition in 1830, 3 swordsmiths , , and were added to the list. |
https://en.wikipedia.org/wiki/British%20carriage%20and%20wagon%20numbering%20and%20classification | A number of different numbering and classification schemes have been used for carriages and wagons on Britain's railways, and this page explains the principal systems. Carriages and wagons (either not self-propelled, or part of a multiple unit which has power units distributed throughout a semi-permanent formation of carriages) have frequently had similar arrangements for classification and numbering, so are considered together. There are also links to other pages that deal in greater depth with the particulars of individual types.
Note on classification
Carriage and wagon classification has never been quite the same as locomotive and multiple unit classification. For most railways, specific types were identified by their Diagram Number. This could simply be arranged by consecutive number, or there could be some greater organisation of numbers so that similar types were grouped together.
However, carriages and wagons have rarely been referred to in general terms by their Diagram Number. Instead there have been a variety of other codes and designations, referring to generic designs rather than specific types. For instance, there were the BR (adapted from the LNER system) and LMS carriage codes, which indicated interior layout or usage. The Great Western Railway (GWR) identified some of their non-passenger carriages and wagons through a series of animal designations, including sea life for departmental (non-revenue earning) stock, followed by a letter for detail differences, |
https://en.wikipedia.org/wiki/Crystal%20Reports | Crystal Reports is a business intelligence application marketed to small- and medium-sized businesses by SAP.
History
Terry Cunningham and the Cunningham Group originated the software in 1984. Crystal Services Inc. marketed the product (originally called "Quik Reports") when they could not find a suitable commercial report writer for an accounting software they developed add-on products for, which was ACCPAC Plus for DOS (later acquired by Sage). After producing versions 1.0 through 3.0, Crystal Services was acquired by Seagate Technology in 1994. Crystal Services was combined with Holistic Systems to form the Information Management Group of Seagate Software, which later rebranded as Crystal Decisions and produced versions 4.0 through 9.0. Crystal Decisions was acquired in December 2003 by BusinessObjects, which produced versions 10, 11 (XI) and version 12 (2008).
SAP acquired BusinessObjects on October 8, 2007, and released Crystal Reports 2011 (version 14) on May 3, 2011. The latest version released is Crystal Reports 2020 (14.3.x) on June 13, 2020.
The file extension for Crystal Reports' proprietary file format is .rpt. The design file can be saved without data, or with data for later viewing or sharing. Introduced with the release of Crystal Reports 2011 (version 14.0), the read-only .rptr file extension option allows for viewing, but cannot be modified once exported.
Several other applications, including Microsoft Visual Studio versions 2003 through 2008, and Borla |
https://en.wikipedia.org/wiki/Crystal%20Decisions | Crystal Decisions (previously known as Seagate Software Information Management Group) was a company that was known for its business intelligence products.
The company was formed when hard disk drive manufacturer Seagate Technology acquired Holistic Systems and Crystal Services with the intention of pursuing better profit margins in the software market. Holistic Systems had a wide range of sales offices, infrastructure and the Holos OLAP product, whilst Crystal Services had good OEM deals for the Crystal Reports database reporting product that they had written. The first new product from the combined company was Seagate Info, which later evolved to become known as Crystal Enterprise. Crystal Analysis followed as an OLAP client.
The company's structure reflected its heritage, with OLAP technologies being developed out of the former Holistic Systems R&D site in Ipswich, Suffolk, England and Relational Database technologies being developed out of the former Crystal Services R&D centre in Vancouver, British Columbia, Canada.
Crystal Decisions was acquired by Business Objects in December 2003. As part of this acquisition, the former research and development site in Ipswich, Suffolk, England, was closed with a loss of about 80 jobs in order to centralize development in Vancouver and Paris, with the support for the Holos product being outsourced to Raspberry Software based near Ipswich.
The Holos product line has now ceased.
Business Objects was purchased by SAP in March 2008.
|
https://en.wikipedia.org/wiki/Hard%20spheres | Hard spheres are widely used as model particles in the statistical mechanical theory of fluids and solids. They are defined simply as impenetrable spheres that cannot overlap in space. They mimic the extremely strong ("infinitely elastic bouncing") repulsion that atoms and spherical molecules experience at very close distances. Hard spheres systems are studied by analytical means, by molecular dynamics simulations, and by the experimental study of certain colloidal model systems. The hard-sphere system provides a generic model that explains the quasiuniversal structure and dynamics of simple liquids.
Formal definition
Hard spheres of diameter are particles with the following pairwise interaction potential:
where and are the positions of the two particles.
Hard-spheres gas
The first three virial coefficients for hard spheres can be determined analytically
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Higher-order ones can be determined numerically using Monte Carlo integration. We list
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A table of virial coefficients for up to eight dimensions can be found on the page Hard sphere: virial coefficients.
The hard sphere system exhibits a fluid-solid phase transition between the volume fractions of freezing and melting . The pressure diverges at random close packing for the metastable liquid branch and at close packing for the stable solid branch.
Hard-spheres liquid
The static structure factor of the hard-spheres liquid can be calculate |
https://en.wikipedia.org/wiki/Potts%20model | In statistical mechanics, the Potts model, a generalization of the Ising model, is a model of interacting spins on a crystalline lattice. By studying the Potts model, one may gain insight into the behaviour of ferromagnets and certain other phenomena of solid-state physics. The strength of the Potts model is not so much that it models these physical systems well; it is rather that the one-dimensional case is exactly solvable, and that it has a rich mathematical formulation that has been studied extensively.
The model is named after Renfrey Potts, who described the model near the end of his 1951 Ph.D. thesis. The model was related to the "planar Potts" or "clock model", which was suggested to him by his advisor, Cyril Domb. The four-state Potts model is sometimes known as the Ashkin–Teller model, after Julius Ashkin and Edward Teller, who considered an equivalent model in 1943.
The Potts model is related to, and generalized by, several other models, including the XY model, the Heisenberg model and the N-vector model. The infinite-range Potts model is known as the Kac model. When the spins are taken to interact in a non-Abelian manner, the model is related to the flux tube model, which is used to discuss confinement in quantum chromodynamics. Generalizations of the Potts model have also been used to model grain growth in metals, coarsening in foams, and statistical properties of proteins. A further generalization of these methods by James Glazier and Francois Graner, known a |
https://en.wikipedia.org/wiki/Narendra%20Karmarkar | Narendra Krishna Karmarkar (born circa 1956) is an Indian mathematician. Karmarkar developed Karmarkar's algorithm. He is listed as an ISI highly cited researcher.
He invented one of the first provably polynomial time algorithms for linear programming, which is generally referred to as an interior point method. The algorithm is a cornerstone in the field of linear programming. He published his famous result in 1984 while he was working for Bell Laboratories in New Jersey.
Biography
Karmarkar received his B.Tech in Electrical Engineering from IIT Bombay in 1978, MS from the California Institute of Technology in 1979, and PhD in Computer Science from the University of California, Berkeley in 1983 under the supervision of Richard M. Karp.
Karmarkar was a post-doctoral research fellow at IBM research (1983), Member of Technical Staff and fellow at Mathematical Sciences Research Center, AT&T Bell Laboratories (1983–1998), professor of mathematics at M.I.T. (1991), at Institute for Advanced study, Princeton (1996), and Homi Bhabha Chair Professor at the Tata Institute of Fundamental Research in Mumbai from 1998 to 2005. He was the scientific advisor to the chairman of the TATA group (2006–2007). During this time, he was funded by Ratan Tata to scale-up the supercomputer he had designed and prototyped at TIFR. The scaled-up model ranked ahead of supercomputer in Japan at that time and achieved the best ranking India ever achieved in supercomputing. He was the founding director of |
https://en.wikipedia.org/wiki/Network%20automaton | A network automaton (plural network automata) is a mathematical system consisting of a network of nodes that evolves over time according to predetermined rules. It is similar in concept to a cellular automaton, but much less studied.
Stephen Wolfram's book A New Kind of Science, which is primarily concerned with cellular automata, briefly discusses network automata, and suggests (without positive evidence) that the universe might at the very lowest level be a network automaton.
Networks
Cellular automata |
https://en.wikipedia.org/wiki/Ferredoxin | Ferredoxins (from Latin ferrum: iron + redox, often abbreviated "fd") are iron–sulfur proteins that mediate electron transfer in a range of metabolic reactions. The term "ferredoxin" was coined by D.C. Wharton of the DuPont Co. and applied to the "iron protein" first purified in 1962 by Mortenson, Valentine, and Carnahan from the anaerobic bacterium Clostridium pasteurianum.
Another redox protein, isolated from spinach chloroplasts, was termed "chloroplast ferredoxin". The chloroplast ferredoxin is involved in both cyclic and non-cyclic photophosphorylation reactions of photosynthesis. In non-cyclic photophosphorylation, ferredoxin is the last electron acceptor thus reducing the enzyme NADP+ reductase. It accepts electrons produced from sunlight-excited chlorophyll and transfers them to the enzyme ferredoxin: NADP+ oxidoreductase .
Ferredoxins are small proteins containing iron and sulfur atoms organized as iron–sulfur clusters. These biological "capacitors" can accept or discharge electrons, with the effect of a change in the oxidation state of the iron atoms between +2 and +3. In this way, ferredoxin acts as an electron transfer agent in biological redox reactions.
Other bioinorganic electron transport systems include rubredoxins, cytochromes, blue copper proteins, and the structurally related Rieske proteins.
Ferredoxins can be classified according to the nature of their iron–sulfur clusters and by sequence similarity.
Bioenergetics of ferredoxins
Ferredoxins typical |
https://en.wikipedia.org/wiki/Powerset%20construction | In the theory of computation and automata theory, the powerset construction or subset construction is a standard method for converting a nondeterministic finite automaton (NFA) into a deterministic finite automaton (DFA) which recognizes the same formal language. It is important in theory because it establishes that NFAs, despite their additional flexibility, are unable to recognize any language that cannot be recognized by some DFA. It is also important in practice for converting easier-to-construct NFAs into more efficiently executable DFAs. However, if the NFA has n states, the resulting DFA may have up to 2n states, an exponentially larger number, which sometimes makes the construction impractical for large NFAs.
The construction, sometimes called the Rabin–Scott powerset construction (or subset construction) to distinguish it from similar constructions for other types of automata, was first published by Michael O. Rabin and Dana Scott in 1959.
Intuition
To simulate the operation of a DFA on a given input string, one needs to keep track of a single state at any time: the state that the automaton will reach after seeing a prefix of the input. In contrast, to simulate an NFA, one needs to keep track of a set of states: all of the states that the automaton could reach after seeing the same prefix of the input, according to the nondeterministic choices made by the automaton. If, after a certain prefix of the input, a set of states can be reached, then after the next input |
https://en.wikipedia.org/wiki/Protein%20kinase%20C | In cell biology, Protein kinase C, commonly abbreviated to PKC (EC 2.7.11.13), is a family of protein kinase enzymes that are involved in controlling the function of other proteins through the phosphorylation of hydroxyl groups of serine and threonine amino acid residues on these proteins, or a member of this family. PKC enzymes in turn are activated by signals such as increases in the concentration of diacylglycerol (DAG) or calcium ions (Ca2+). Hence PKC enzymes play important roles in several signal transduction cascades.
In biochemistry, the PKC family consists of fifteen isozymes in humans. They are divided into three subfamilies, based on their second messenger requirements: conventional (or classical), novel, and atypical. Conventional (c)PKCs contain the isoforms α, βI, βII, and γ. These require Ca2+, DAG, and a phospholipid such as phosphatidylserine for activation. Novel (n)PKCs include the δ, ε, η, and θ isoforms, and require DAG, but do not require Ca2+ for activation. Thus, conventional and novel PKCs are activated through the same signal transduction pathway as phospholipase C. On the other hand, atypical (a)PKCs (including protein kinase Mζ and ι / λ isoforms) require neither Ca2+ nor diacylglycerol for activation. The term "protein kinase C" usually refers to the entire family of isoforms. The different classes of PKCs found in jawed vertebrates originate from 5 ancestral PKC family members (PKN, aPKC, cPKC, nPKCE, nPKCD) that expanded due to genome duplicati |
https://en.wikipedia.org/wiki/Negotiation%20theory | The foundations of negotiation theory are decision analysis, behavioral decision-making, game theory, and negotiation analysis.
Another classification of theories distinguishes between Structural Analysis, Strategic Analysis, Process Analysis, Integrative Analysis and behavioral analysis of negotiations.
Negotiation is a strategic discussion that resolves an issue in a way that both parties find acceptable. Individuals should make separate, interactive decisions; and negotiation analysis considers how groups of reasonably bright individuals should and could make joint, collaborative decisions. These theories are interleaved and should be approached from the synthetic perspective.
Common assumptions of most theories
Negotiation is a specialized and formal version of conflict resolution, most frequently employed when important issues must be agreed upon. Negotiation is necessary when one party requires the other party's agreement to achieve its aim. The aim of negotiating is to build a shared environment leading to long-term trust, and it often involves a third, neutral party to extract the issues from the emotions and keep the individuals concerned focused. It is a powerful method for resolving conflict and requires skill and experience. Henry Kissinger (1969) defines negotiation as "a process of combining conflicting positions into a common position under a decision rule of unanimity, a phenomenon in which the outcome is determined by the process." Druckman (1986) adds that |
https://en.wikipedia.org/wiki/Curt%20Backeberg | Curt Backeberg (2 August 1894 in Lüneburg, Germany – 14 January 1966) was a German horticulturist especially known for the collection and classification of cacti.
Biography
He travelled extensively through Central and South America, and published a number of books on cacti, including the six-volume, 4,000-page Die Cactaceae, 1958–1962, and the Kakteenlexikon, first appearing in 1966 and updated posthumously.
Although he collected and described many new species and defined a number of new genera, much of his work was based on faulty assumptions about the evolution of cacti and was too focused on geographic distribution; many of his genera have since been reorganized or abandoned. The botanist David Hunt is quoted as saying that he "left a trail of nomenclatural chaos that will probably vex cactus taxonomists for centuries." Nevertheless, his observations regarding the subtle variations among cacti have proven useful for hobbyists, who continue to use many cactus names proposed or upheld in his works.
In 1954, the Mexican botanist Helia Bravo Hollis described a new genus, and named it Backebergia in honor of Curt Backeberg.
Curt Backeberg was struck by a heart attack and died on 14 January 1966.
See also
Cacti
Backebergia
References
20th-century German botanists
Botanists active in Central America
Botanists active in South America
1894 births
1966 deaths
People from Lüneburg
Cactologists |
https://en.wikipedia.org/wiki/Injector | An injector is a system of ducting and nozzles used to direct the flow of a high-pressure fluid in such a way that a lower pressure fluid is entrained in the jet and carried through a duct to a region of higher pressure. It is a fluid-dynamic pump with no moving parts except a valve to control inlet flow.
Steam injector
The steam injector is a common device used for delivering water to steam boilers, especially in steam locomotives. It is a typical application of the injector principle used to deliver cold water to a boiler against its own pressure, using its own live or exhaust steam, replacing any mechanical pump. When first developed, its operation was intriguing because it seemed paradoxical, almost like perpetual motion, but it was later explained using thermodynamics. Other types of injector may use other pressurised motive fluids such as air.
Depending on the application, an injector can also take the form of an eductor-jet pump, a water eductor or an aspirator. An ejector operates on similar principles to create a vacuum feed connection for braking systems etc.
History
Giffard
The injector was invented by Henri Giffard in early 1850s and patented in France in 1858, for use on steam locomotives. It was patented in the United Kingdom by Sharp, Stewart and Company of Glasgow.
After some initial scepticism resulting from the unfamiliar and superficially paradoxical mode of operation, the injector became widely adopted for steam locomotives as an alternative to mech |
https://en.wikipedia.org/wiki/Gauss%E2%80%93Newton%20algorithm | The Gauss–Newton algorithm is used to solve non-linear least squares problems, which is equivalent to minimizing a sum of squared function values. It is an extension of Newton's method for finding a minimum of a non-linear function. Since a sum of squares must be nonnegative, the algorithm can be viewed as using Newton's method to iteratively approximate zeroes of the components of the sum, and thus minimizing the sum. In this sense, the algorithm is also an effective method for solving overdetermined systems of equations. It has the advantage that second derivatives, which can be challenging to compute, are not required.
Non-linear least squares problems arise, for instance, in non-linear regression, where parameters in a model are sought such that the model is in good agreement with available observations.
The method is named after the mathematicians Carl Friedrich Gauss and Isaac Newton, and first appeared in Gauss' 1809 work Theoria motus corporum coelestium in sectionibus conicis solem ambientum.
Description
Given functions (often called residuals) of variables with the Gauss–Newton algorithm iteratively finds the value of the variables that minimize the sum of squares
Starting with an initial guess for the minimum, the method proceeds by the iterations
where, if r and β are column vectors, the entries of the Jacobian matrix are
and the symbol denotes the matrix transpose.
At each iteration, the update can be found by rearranging the previous equation in |
https://en.wikipedia.org/wiki/N-vector%20model | In statistical mechanics, the n-vector model or O(n) model is a simple system of interacting spins on a crystalline lattice. It was developed by H. Eugene Stanley as a generalization of the Ising model, XY model and Heisenberg model. In the n-vector model, n-component unit-length classical spins are placed on the vertices of a d-dimensional lattice. The Hamiltonian of the n-vector model is given by:
where the sum runs over all pairs of neighboring spins and denotes the standard Euclidean inner product. Special cases of the n-vector model are:
: The self-avoiding walk
: The Ising model
: The XY model
: The Heisenberg model
: Toy model for the Higgs sector of the Standard Model
The general mathematical formalism used to describe and solve the n-vector model and certain generalizations are developed in the article on the Potts model.
Continuum limit
The continuum limit can be understood to be the sigma model. This can be easily obtained by writing the Hamiltonian in terms of the product
where is the "bulk magnetization" term. Dropping this term as an overall constant factor added to the energy, the limit is obtained by defining the Newton finite difference as
on neighboring lattice locations Then in the limit , where is the gradient in the direction. Thus, in the limit,
which can be recognized as the kinetic energy of the field in the sigma model. One still has two possibilities for the spin : it is either taken from a discrete set of spins (the Potts m |
https://en.wikipedia.org/wiki/ISTAT | ISTAT may refer to:
International Society of Transport Aircraft Trading
National Institute of Statistics (Italy) or Istituto Nazionale di Statistica
i-STAT, a blood analyzer made by Abbott Laboratories |
https://en.wikipedia.org/wiki/Quenching | In materials science, quenching is the rapid cooling of a workpiece in water, oil, polymer, air, or other fluids to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phase transformations, from occurring. It does this by reducing the window of time during which these undesired reactions are both thermodynamically favorable, and kinetically accessible; for instance, quenching can reduce the crystal grain size of both metallic and plastic materials, increasing their hardness.
In metallurgy, quenching is most commonly used to harden steel by inducing a martensite transformation, where the steel must be rapidly cooled through its eutectoid point, the temperature at which austenite becomes unstable. In steel alloyed with metals such as nickel and manganese, the eutectoid temperature becomes much lower, but the kinetic barriers to phase transformation remain the same. This allows quenching to start at a lower temperature, making the process much easier. High-speed steel also has added tungsten, which serves to raise kinetic barriers, which among other effects gives material properties (hardness and abrasion resistance) as though the workpiece had been cooled more rapidly than it really has. Even cooling such alloys slowly in air has most of the desired effects of quenching; high-speed steel weakens much less from heat cycling due to high-speed cutting.
Extremely rapid cooling can prevent the formation of a |
https://en.wikipedia.org/wiki/Rupture%20of%20membranes | Rupture of membranes (ROM) or amniorrhexis is a term used during pregnancy to describe a rupture of the amniotic sac. Normally, it occurs spontaneously at full term either during or at the beginning of labor. Rupture of the membranes is known colloquially as "breaking the water" or as one's "water breaking". A premature rupture of membranes (PROM) is a rupture of the amnion that occurs at full term and prior to the onset of labor. In cases of PROM, options include expectant management without intervention, or interventions such as oxytocin or other methods of labor induction, and both are usually accompanied by close monitoring of maternal and fetal health. Preterm premature rupture of membranes (PPROM) is when water breaks both before the onset of labor and before the pregnancy's 37 week gestation. In the United States, more than 120,000 pregnancies per year are affected by a premature rupture of membranes, which is the cause of about one third of preterm deliveries.
Sometimes, a child is born with no rupture of the amniotic sac (no rupture of membranes). In such cases, the child may still be entirely within the sac once born; such a birth is known as an en-caul birth.
Effects
When the amniotic sac ruptures, production of prostaglandins increases and the cushioning between the fetus and uterus is decreased, both of which are processes that increase the frequency and intensity of uterine contractions.
On occasion, with the rupture of membranes, particularly if the head is |
https://en.wikipedia.org/wiki/Gretl | gretl is an open-source statistical package, mainly for econometrics. The name is an acronym for Gnu Regression, Econometrics and Time-series Library.
It has both a graphical user interface (GUI) and a command-line interface. It is written in C, uses GTK+ as widget toolkit for creating its GUI, and calls gnuplot for generating graphs. The native scripting language of gretl is known as hansl (see below); it can also be used together with TRAMO/SEATS, R, Stata, Python, Octave, Ox and Julia.
It includes natively all the basic statistical techniques employed in contemporary Econometrics and Time-Series Analysis. Additional estimators and tests are available via user-contributed function packages, which are written in hansl.
gretl can output models as LaTeX files.
Besides English, gretl is also available in Albanian, Basque, Bulgarian, Catalan, Chinese, Czech, French, Galician, German, Greek, Italian, Polish, Portuguese (both varieties), Romanian, Russian, Spanish, Turkish and Ukrainian.
Gretl has been reviewed several times in the Journal of Applied Econometrics and, more recently, in the Australian Economic Review.
A review also appeared in the Journal of Statistical Software in 2008. Since then, the journal has featured several articles in which gretl is used to implement various statistical techniques.
Supported data formats
gretl offers its own fully documented, XML-based data format.
It can also import ASCII, CSV, databank, EViews, Excel, Gnumeric, GNU Octave, JMulTi |
https://en.wikipedia.org/wiki/Gestational%20sac | The gestational sac is the large cavity of fluid surrounding the embryo. During early embryogenesis it consists of the extraembryonic coelom, also called the chorionic cavity. The gestational sac is normally contained within the uterus. It is the only available structure that can be used to determine if an intrauterine pregnancy exists until the embryo can be identified.
On obstetric ultrasound, the gestational sac is a dark (anechoic) space surrounded by a white (hyperechoic) rim.
Structure
The gestational sac is spherical in shape, and is usually located in the upper part (fundus) of the uterus. By approximately nine weeks of gestational age, due to folding of the trilaminar germ disc, the amniotic sac expands and occupy the majority of the volume of the gestational sac, eventually reducing the extraembryonic coelom (the gestational sac or the chorionic cavity) to a thin layer between the parietal somatopleuric and visceral splanchnopleuric layer of extraembryonic mesoderm.
Development
During embryogenesis, the extraembryonic coelom (or chorionic cavity) that constitutes the gestational sac is a portion of the conceptus consisting of a cavity between Heuser's membrane and the trophoblast.
During formation of the primary yolk sac, some of the migrating hypoblast cells differentiate into mesenchymal cells that fill the space between Heuser's membrane and the trophoblast, forming the extraembryonic mesoderm. As development progresses, small lacunae begin to form within the |
https://en.wikipedia.org/wiki/Agricultural%20biodiversity | Agricultural biodiversity or agrobiodiversity is a subset of general biodiversity pertaining to agriculture. It can be defined as "the variety and variability of animals, plants and micro-organisms at the genetic, species and ecosystem levels that sustain the ecosystem structures, functions and processes in and around production systems, and that provide food and non-food agricultural products.” It is managed by farmers, pastoralists, fishers and forest dwellers, agrobiodiversity provides stability, adaptability and resilience and constitutes a key element of the livelihood strategies of rural communities throughout the world. Agrobiodiversity is central to sustainable food systems and sustainable diets. The use of agricultural biodiversity can contribute to food security, nutrition security, and livelihood security, and it is critical for climate adaptation and climate mitigation.
Etymology
It is not clear when exactly the term agrobiodiversity was coined nor by whom. The 1990 annual report of the International Board for Plant Genetic Resources (IBPGR, now Bioversity International) is one of the earliest references to biodiversity in the context of agriculture. Most references to agricultural biodiversity date from the late 1990s onwards.
While similar, different definitions are used by different bodies to describe biodiversity in connection with food production. CGIAR tends to use agricultural biodiversity or agrobiodiversity, while the Food and Agriculture Organization o |
https://en.wikipedia.org/wiki/Transient%20tachypnea%20of%20the%20newborn | Transient tachypnea of the newborn is a respiratory problem that can be seen in the newborn shortly after delivery. It is caused by retained fetal lung fluid due to impaired clearance mechanisms. It is the most common cause of respiratory distress in term neonates. It consists of a period of tachypnea (rapid breathing (higher than the normal range of 30-60 times per minute). Usually, this condition resolves over 24–72 hours. Treatment is supportive and may include supplemental oxygen and antibiotics. The chest x-ray shows hyperinflation of the lungs including prominent pulmonary vascular markings, flattening of the diaphragm, and fluid in the horizontal fissure of the right lung.
Signs and symptoms
Symptoms of transient tachypnea of the newborn include respiratory distress and rapid breathing (tachypnea). This condition usually occurs within the first two hours of birth in full term and late term newborn infants.
Pathophysiology
Due to the higher incidence of transient tachypnea of the newborn in infants delivered by caesarean section, it has been postulated that it could result from a delayed absorption of fetal lung fluid from the pulmonary lymphatic system. The increased fluid in the lungs leads to increased airway resistance and reduced lung compliance. It is thought this could be from lower levels of circulating catecholamines after a caesarean section, which are believed to be necessary to alter the function of the ENaC channel to absorb excess fluid from the lungs. |
https://en.wikipedia.org/wiki/X%20series | X series or xSeries or Series-X or variation, may refer to:
Nokia Xseries, a family of mobile phones.
Sony X series
Sony Ericsson X series, a series of cell phones
Sony Vaio X series, a series of laptops
Fujifilm X series, a series of digital cameras
Yamaha's X-series motorcycles
BMW X-series vehicles, see List of BMW vehicles
IBM/Lenovo X series
IBM System x, previously eServer xSeries
ThinkPad X series, a series of laptops
Intel Core X-Series, a series of computer CPUs, under the Core brand from Intel
X (video game series), a space combat and trading game series
X the album, a series of Christian rock compilation albums
X-Men (film series) (2000-2020, FOX), frequently called the "X" films, both X2 and X3 being so named
Northgate SeriesX, a line of computers from Northgate Information Solutions
Xbox Series X, 9th generation videogame console from Microsoft
X-planes, a series of US experimental aircraft
See also
W series (disambiguation)
Y series (disambiguation)
Series (disambiguation)
X (disambiguation) |
https://en.wikipedia.org/wiki/Assist%20%28association%20football%29 | In association football, an assist is a contribution by a player which helps to score a goal. Statistics for assists made by players may be kept officially by the organisers of a competition, or unofficially by, for example, journalists or organisers of fantasy football competitions. Recording assists is not part of the official Laws of the Game and the criteria for an assist to be awarded may vary. Record of assists was virtually not kept at all until the end of the 20th century, although reports of matches commonly described a player as having "made" one or more goals. Since the 1990s, some leagues have kept official record of assists and based awards on them.
Criteria
Most commonly, an assist is credited to a player for passing or crossing the ball to the scorer. It may also be awarded to a player whose shot rebounds (off a defender, goalkeeper or goalpost) to a teammate who scores. Some systems may credit an assist to a player who wins a penalty kick or a free kick for another player to convert, or to an attacking player for contributing to an own goal. A goal may be unassisted, or have one assist; some systems allow for two assists.
FIFA World Cup
FIFA's Technical Study Group is responsible for awarding assist points at the FIFA World Cup. In the Technical Study Group's report on the 1986 World Cup, the authors calculated for the first time unofficial statistics for assists, developing the following criteria:
An assist was awarded to the player who had given the las |
https://en.wikipedia.org/wiki/Erna%20Rosenstein | Erna Rosenstein was a Polish painter and Holocaust survivor. She was born on May 17, 1913, in Lviv, Austria-Hungary (now Ukraine). She was associated with the surrealist movement both as a visual artist and a writer. she studied at the in Vienna and the Academy of Fine Arts in Kraków. She was associated with the pre-war Kraków Group.
Rosenstein's parents were murdered after escaping Warsaw in 1942. Rosenstein survived World War II, hiding under various aliases.
After the war, Rosenstein co-founded the Second Kraków Group. In 1955 she was included in the exhibit Nine Artists along with fellow artist Tadeusz Brzozowski, Maria Jarema, Tadeusz Kantor, , , Jerzy Nowosielski, Jerzy Skarżyński, and . In 1967 a retrospective of her work was held at the Zachęta National Gallery of Art.
Rosenstein's brother, the Austrian professor Paul N. Rosenstein-Rodan went on to become a Boston University professor and economist. He coined the term "underdeveloped countries". She was married to Polish-Jewish literary critic Artur Sandauer. Rosenstein died on November 10, 2004, in Warsaw, Poland.
Her work is in the collection of the Art Institute of Chicago In 2021 the Hauser & Wirth Gallery in New York held her first solo exhibition outside of Poland, entitled Once Upon a Time. In 2023 her work was included in the exhibition Action, Gesture, Paint: Women Artists and Global Abstraction 1940-1970 at the Whitechapel Gallery in London.
References
External links
Erna Rosenstein Bio
Obituary |
https://en.wikipedia.org/wiki/Beeching | Beeching is an English surname. Either a derivative of the old English bece, bæce "stream", hence "dweller by the stream" or of the old English bece "beech-tree" hence "dweller by the beech tree".
People called Beeching include:-
Henry Beeching (1859–1919) clergyman, author and poet
Jack Beeching (John Charles Stuart Beeching) (1922–2001), British poet
Richard Beeching (1913–1985), chairman of British Railways
Thomas Beeching (1900–1971), English soldier and cricketer
Vicky Beeching (Victoria Louise Beeching) (born 1979), British-born Christian singer
See also
Beeching Axe, informal name for the report "The Reshaping of British Railways"
References
English-language surnames |
https://en.wikipedia.org/wiki/Andrew%20Johnson%20%28footballer%2C%20born%201981%29 | Andrew Johnson (born 10 February 1981) is an English former professional footballer who played as a striker. He played for Birmingham City, Crystal Palace, Everton, Fulham and Queens Park Rangers.
A legend at Crystal Palace, Johnson scored more than one goal per every other game in 140 appearances and helped Crystal Palace win promotion to the Premier League
He was capped eight times for England.
Club career
Birmingham City
Johnson was born in Bedford, Bedfordshire, and started his career at Luton Town's Academy. He moved on to Birmingham City, where he signed his first professional contract on 11 March 1998. He missed a deciding penalty in the 2001 League Cup Final penalty shoot-out defeat to Liverpool.
After making over 100 appearances for the Blues, he was sold to Crystal Palace in 2002, following Birmingham's promotion into the Premier League. Johnson was used as the makeweight in a transfer deal for Clinton Morrison, valued at £750,000 for the purposes of the transaction.
Crystal Palace
Johnson's made a strong start to his career at Palace by scoring a hat-trick in the 5–0 thrashing of rivals Brighton & Hove Albion on 26 October 2002, and then another, in the next match, at Walsall. Despite this, he made few appearances until manager Trevor Francis was dismissed with the Eagles mid-table, and replaced by Steve Kember. Kember was replaced by Ian Dowie a few months into the 2003–04 season. Under the new manager, Johnson ended the season as top scorer in the 2003–04 |
https://en.wikipedia.org/wiki/Mirror%20neuron | A mirror neuron is a neuron that fires both when an organism acts and when the organism observes the same action performed by another. Thus, the neuron "mirrors" the behavior of the other, as though the observer were itself acting. Mirror neurons are not always physiologically distinct from other types of neurons in the brain; their main differentiating factor is their response patterns. By this definition, such neurons have been directly observed in humans and primate species, and in birds.
In humans, brain activity consistent with that of mirror neurons has been found in the premotor cortex, the supplementary motor area, the primary somatosensory cortex, and the inferior parietal cortex. The function of the mirror system in humans is a subject of much speculation. Birds have been shown to have imitative resonance behaviors and neurological evidence suggests the presence of some form of mirroring system.
To date, no widely accepted neural or computational models have been put forward to describe how mirror neuron activity supports cognitive functions.
The subject of mirror neurons continues to generate intense debate. In 2014, Philosophical Transactions of the Royal Society B published a special issue entirely devoted to mirror neuron research. Some researchers speculate that mirror systems may simulate observed actions, and thus contribute to theory of mind skills, while others relate mirror neurons to language abilities. Neuroscientists such as Marco Iacoboni have argue |
https://en.wikipedia.org/wiki/NeuRFon | The neuRFon project (named for a combination of "neuron" and "RF") was a research program begun in 1999 at Motorola Labs to develop ad hoc wireless networking for wireless sensor network applications. The biological analogy was that, while individual neurons were not very useful, in a large network they became very powerful; the same was thought to hold true for simple, low power wireless devices. Much of the technology developed in the neuRFon program was placed in the IEEE 802.15.4 standard and in the Zigbee specification; examples are the 2.4 GHz physical layer of the IEEE 802.15.4 standard and significant portions of the Zigbee multi-hop routing protocol.
References
External links
IEEE 802.15.4
ZigBee Alliance
Wireless sensor network |
https://en.wikipedia.org/wiki/Arna%2C%20Norway | Arna is a borough in the city of Bergen in Vestland county, Norway. It is one of eight boroughs in Bergen. It encompasses the northeastern part of the municipality of Bergen. Arna was merged into the city of Bergen in 1972. Prior to that, it was the separate municipality of Arna. The main population centres in the borough are the villages of Indre Arna, Ytre Arna, and Espeland.
Location
The borough of Arna has approximately 13,000 inhabitants. It lies along the Sørfjorden, east of the centre of the city of Bergen (the borough of Bergenhus). The large mountains Ulriken and Rundemanen lie between the city centre and Arna. Arna is geographically close to central Bergen, but it takes some time to drive there by road as there is currently no road tunnel. However, a train journey from Arna Station to Bergen only takes eight minutes since there is a train tunnel (Ulriken Tunnel) through the mountain. Takvam Station and Trengereid Station are also located within the borough, a little east of the village of Indre Arna. The European route E16 highway runs through Arna, along the shoreline.
The borough of Arna consists of many smaller "village" areas, since this borough includes some of the most rural parts of the city of Bergen. The village areas include Haukeland, Unneland, Espeland, Rødland, Haugland, Gaupås, Ytre Arna, Indre Arna, Arnatveit, Garnes, Takvam, Songstad, and Trengereid.
Name
The Old Norse forms of the name were Arni (nominative) and Arna (dative), and this |
https://en.wikipedia.org/wiki/Q10 | Q10 or Q-10 may refer to:
Science and technology
Q10 (temperature coefficient)
Coenzyme Q10, a dietary supplement
BlackBerry Q10, a smartphone
Transportation
Q10 (New York City bus)
MMIST CQ-10 Snowgoose, a U.S. Army cargo UAV
LNER Class Q10, a class of British steam locomotives
Other uses
Q10 Wind Farm, an offshore wind farm in the Netherlands, now renamed to Luchterduinen
Quran 10, Yūnus, 10th chapter
See also
10Q, a quarterly financial report |
https://en.wikipedia.org/wiki/Ovarian%20clear-cell%20carcinoma | Ovarian clear-cell carcinoma, or clear-cell carcinoma of the ovary, also called ovarian clear-cell adenocarcinoma, is one of several subtypes of ovarian carcinoma – a subtype of epithelial ovarian cancer, in contrast to non-epithelial cancers. According to research, most ovarian cancers start at the epithelial layer which is the lining of the ovary. Within this epithelial group ovarian clear-cell carcinoma makes up 5–10%.
It was recognized as a separate category of ovarian cancer by the World Health Organization in 1973. Its incidence rate differs across various ethnic groups. Reports from the United States show that the highest rates are among Asians with 11.1% versus whites with 4.8% and blacks at 3.1%. These numbers are consistent with the finding that although clear-cell carcinomas are rare in Western countries they are much more common in parts of Asia.
Background
There are two subtypes of ovarian carcinoma – epithelial and nonepithelial; ovarian clear-cell carcinoma is an epithelial ovarian cancer. The other major subtypes within this group include high-grade serous, endometrioid, mucinous, and low-grade serous. The serous type is the most common form of epithelial ovarian tumors. Cord-stromal and germ cell belong to the nonepithelial category which are much less common.
Structure and function
Ovarian clear-cell carcinoma often occurs as a pelvic mass that rarely appears bilaterally. The cells usually contain glycogen with large clear cytoplasm. It is also associate |
https://en.wikipedia.org/wiki/Serous%20tumour | A serous tumour is a neoplasm that typically has papillary to solid formations of tumor cells with crowded nuclei, and which typically arises on the modified Mullerian-derived serous membranes that surround the ovaries in females. Such ovarian tumors are part of the surface epithelial-stromal tumour group of ovarian tumors. They are common neoplasms with a strong tendency to occur bilaterally, and they account for approximately a quarter of all ovarian tumors.
Rarely, serous tumors arise from within the uterus, notably uterine serous carcinoma, which typically arises in postmenopausal women. Rarely, serous tumors arise from other parts of the peritoneum, including serous primary peritoneal carcinomas. Even more rarely they arise in other body locations, such as the lungs.
Ovarian serous tumours
Low grade
The "low grade" classification of serous tumors includes benign and borderline tumors, as well as low grade malignant tumors. Benign serous tumors are distinguished from borderline tumors by the absence of cellular stratification. Stromal invasion distinguishes borderline tumors from low grade malignant tumors. Surgery is curative for benign tumors, and likely curative for other low grade tumors.
Benign serous tumors include serous cystadenomas, cystadenofibromas, and adenofibromas. Benign and borderline serous tumours are commonly unilocular. Benign tumors contain clear fluid and have a smooth lining composed of columnar epithelial cells with cilia. On gross examinati |
https://en.wikipedia.org/wiki/Sertoli%E2%80%93Leydig%20cell%20tumour | Sertoli–Leydig cell tumour is a group of tumors composed of variable proportions of Sertoli cells, Leydig cells, and in the case of intermediate and poorly differentiated neoplasms, primitive gonadal stroma and sometimes heterologous elements.
Sertoli–Leydig cell tumour (a sex-cord stromal tumor), is a testosterone-secreting ovarian tumor and is a member of the sex cord-stromal tumour group of ovarian and testicular cancers. The tumour occurs in early adulthood (not seen in newborn), is rare, comprising less than 1% of testicular tumours. While the tumour can occur at any age, it occurs most often in young adults. Recent studies have shown that many cases of Sertoli–Leydig cell tumor of the ovary are caused by germline mutations in the DICER1 gene. These hereditary cases tend to be younger, often have a multinodular thyroid goiter and there may be a personal or family history of other rare tumors such as pleuropulmonary blastoma, Wilms tumor and cervical rhabdomyosarcoma.
Closely related terms include arrhenoblastoma and androblastoma. Both terms are classified under Sertoli–Leydig cell tumour in MeSH.
Signs and symptoms
Due to excess testosterone secreted by the tumour, one-third of adult females present with a recent history of progressive masculinization. Masculinization is preceded by anovulation, oligomenorrhoea, amenorrhoea and defeminization. Additional signs include acne and hirsutism, voice deepening, clitoromegaly, temporal hair recession, and an increase in mu |
https://en.wikipedia.org/wiki/Thecoma | Thecomas or theca cell tumors are benign ovarian neoplasms composed only of theca cells. Histogenetically they are classified as sex cord-stromal tumours.
They are typically estrogen-producing and they occur in older women (mean age 59; 84% after menopause). (They can, however, appear before menopause.)
60% of patients present with abnormal uterine bleeding, and 20% have endometrial carcinoma.
Pathologic features
Grossly, the tumour is solid and yellow.
Grossly and microscopically, it consists of the ovarian cortex.
Microscopically, the tumour cells have abundant lipid-filled cytoplasm.
References
External links
Gynaecological neoplasia |
https://en.wikipedia.org/wiki/Granulosa%20cell%20tumour | Granulosa cell tumours are tumours that arise from granulosa cells. They are estrogen secreting tumours and present as large, complex, ovarian masses. These tumours are part of the sex cord–gonadal stromal tumour or non-epithelial group of tumours. Although granulosa cells normally occur only in the ovary, granulosa cell tumours occur in both ovaries and testicles (see ovarian cancer and testicular cancer). These tumours should be considered malignant and treated in the same way as other malignant tumours of ovary. The ovarian disease has two forms, juvenile and adult, both characterized by indolent growth, and therefore has high recovery rates. The staging system for these tumours is the same as for epithelial tumours and most present as stage I. The peak age at which they occur is 50–55 years, but they may occur at any age.
Juvenile granulosa cell tumour is a similar but histologically distinct rare tumour. It too occurs in both the ovary and testis. In the testis it is extremely rare, and has not been reported to be malignant. Although this tumour usually occurs in children (hence its name), it has been reported in adults.
Presentation
Estrogens are produced by functioning tumours, and the clinical presentation depends on the patient's age and sex.
Female
If the patient is postmenopausal, she usually presents with abnormal uterine bleeding, and in some cases hemoperitoneum.
If the patient is of reproductive age, she would present with menometrorrhagia. However, |
https://en.wikipedia.org/wiki/Dysgerminoma | A dysgerminoma is a type of germ cell tumor; it usually is malignant and usually occurs in the ovary.
A tumor of the identical histology but not occurring in the ovary may be described by an alternate name: seminoma in the testis or germinoma in the central nervous system or other parts of the body.
Dysgerminoma accounts for less than 1% of ovarian tumors overall. Dysgerminoma usually occurs in adolescence and early adult life; about 5% occur in pre-pubertal children. Dysgerminoma is extremely rare after age 50. Dysgerminoma occurs in both ovaries in 10% of patients and, in a further 10%, there is microscopic tumor in the other ovary.
Abnormal gonads (due to gonadal dysgenesis and androgen insensitivity syndrome) have a high risk of developing a dysgerminoma. Most dysgerminomas are associated with elevated serum lactic dehydrogenase (LDH), which is sometimes used as a tumor marker.
Signs and symptoms
They are exceptionally associated with hypercalcemia. On gross examination, dysgerminomas present with a smooth, bosselated (knobby) external surface, and is soft, fleshy and either cream-coloured, gray, pink or tan when cut. Microscopic examination typically reveals uniform cells that resemble primordial germ cells. Typically, the stroma contains lymphocytes and about 20% of patients have sarcoid-like granulomas.
Metastases are most often present in the lymph nodes.
Diagnosis
LDH tumour markers is elevated in 95% of the cases.
Treatment
Dysgerminomas, like other semino |
https://en.wikipedia.org/wiki/Germ%20cell%20tumor | Germ cell tumor (GCT) is a neoplasm derived from germ cells. Germ-cell tumors can be cancerous or benign. Germ cells normally occur inside the gonads (ovary and testis). GCTs that originate outside the gonads may be birth defects resulting from errors during development of the embryo.
Classification
GCTs are classified by their histology, regardless of location in the body. However, as more information about the genetics of these tumors become available, they may be classified based on specific gene mutations that characterize specific tumors. They are broadly divided in two classes:
The germinomatous or seminomatous germ-cell tumors (GGCT, SGCT) include only germinoma and its synonyms dysgerminoma and seminoma.
The nongerminomatous or nonseminomatous germ-cell tumors (NGGCT, NSGCT) include all other germ-cell tumors, pure and mixed.
The two classes reflect an important clinical difference. Compared with germinomatous tumors, nongerminomatous tumors tend to grow faster, have an earlier mean age at time of diagnosis (around 25 years versus 35 years, in the case of testicular cancers), and have a lower five-year survival rate. The survival rate for germinomatous tumors is higher in part because these tumors are very sensitive to radiation, and they also respond well to chemotherapy. The prognosis for nongerminomatous tumours has improved dramatically, however, due to the use of platinum-based chemotherapy regimens.
Germinomatous
Nongerminomatous
Mixed
Mixed germ ce |
https://en.wikipedia.org/wiki/Granulosa%20cell | A granulosa cell or follicular cell is a somatic cell of the sex cord that is closely associated with the developing female gamete (called an oocyte or egg) in the ovary of mammals.
Structure and function
In the primordial ovarian follicle, and later in follicle development (folliculogenesis), granulosa cells advance to form a multilayered cumulus oophorus surrounding the oocyte in the preovulatory or antral (or Graafian) follicle.
The major functions of granulosa cells include the production of sex steroids, as well as myriad growth factors thought to interact with the oocyte during its development. The sex steroid production begins with follicle-stimulating hormone (FSH) from the anterior pituitary, stimulating granulosa cells to convert androgens (coming from the thecal cells) to estradiol by aromatase during the follicular phase of the menstrual cycle. However, after ovulation the granulosa cells turn into granulosa lutein cells that produce progesterone. The progesterone may maintain a potential pregnancy and causes production of a thick cervical mucus that inhibits sperm entry into the uterus.
Embryology of ovarian granulosa cells
In the development of the urinary and reproductive organs, the oogonia become invaginated in the gonadal ridge.
The embryological origin of granulosa cells remains controversial. In the 1970s, evidence emerged that the first cells to make contact with the oogonia were of mesonephric origin. It was suggested that mesonephric cells already |
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