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https://en.wikipedia.org/wiki/Vienna%20School%20of%20Dermatology | The Vienna School of Dermatology was a group of dermatologists affiliated to the University of Vienna who became an important reference in the development of modern dermatology in the second half of the 19th century. It was founded by Ferdinand Ritter von Hebra (1816–1888) with the collaboration of his mentor, Carl Freiherr von Rokitansky (1804–1878) and Carl Wedl (1815–1891), a pathologist with interest in skin diseases. Their pupils, Isidor Neumann (1832–1906), Salomon Stricker (1834–1898), Heinrich Auspitz (1834–1885), Moritz Kaposi (1837–1902), all of the same generation; and Paul Gerson Unna (1850–1929) and Salomon Ehrmann (1854–1926), continued the tradition. Unna later became the father of German dermatopathology.
Von Hebra first organized the dermatological service in the Vienna General Hospital. He was inspired by the movement towards a scientific dermatology already established in England by Robert Willan (1757–1812) and Thomas Bateman (1778–1821); and in France by Jean-Louis-Marc Alibert (1768–1837), Laurent-Théodore Biett (1781–1840), Pierre Louis Alphée Cazenave (1795–1877) and Pierre François Olive Rayer (1793–1867). The Vienna School adopted the approach of pathology (as influenced by the great Carl von Rokitansky, a professor of von Hebra) and the doctrine of local causative agents. For example, 2,000 of the first 2,500 dermatological patients treated by von Hebra had scabies.
The members of the Vienna School discovered and described many new diseases and signs, such as:
Auspitz's sign
Eczema herpeticum
Erythema exudativum multiforme
Hebra's disease
Hebra's prurigo
Impetigo herpetiformis
Kaposi-Irgang syndrome
Kaposi's sarcoma
Lichen acuminatus
Lichen planus bullosus
Lichen ruber moniliformis
Lupus erythematosus
Pityriasis rubra
Tinea cruris
Unna-Politzer naevus
Unna's disease
Unna-Thost syndrome
Xeroderma pigmentosa
Bibliography
Finnerud CW. Ferdinand von Hebra and the Vienna school of dermatology. AMA Arch Derm Syphilol. 1952 |
https://en.wikipedia.org/wiki/Digital%20River | Digital River is a private company that provides global e-commerce, payments and marketing services. In 2013, Digital River processed more than $30 billion in online transactions. Digital River is headquartered in Minnetonka, Minnesota.
Company operations
Digital River has a history of acquiring other companies in the e-commerce (including digital software delivery) industry.
Notable acquisitions include:
Simtel (1999)
CCNow (2002)
SWREG (2005)
eSellerate (2006)
Freemerchant.com (discontinued 15 January 2008)
THINK Subscription (2008)
Journey Education Marketing (2010)
Fatfoogoo (2010)
Divestitures
CCNow (sold to Snorrason Holdings 2012)
Journey Education Marketing (2013)
Security failings
A security breach in 2010 resulted in nearly 200,000 customers' data being stolen. A lawsuit followed by Digital River.
In October 2017, the websites for Equifax, and for TransUnion's Central American division were reported to have been redirecting visitors to websites that attempted drive-by downloads of malware disguised as Adobe Flash updates. The attack had been performed by hijacking third-party analytics JavaScript from FireClick. Digital River decommissioned the FireClick platform and released the domain in 2016, so the domain was not owned by Digital River at the time of the attack.
Management history
Joel Ronning was CEO from the company's founding until stepping down in November 2012. In June 2013, Ronning was ranked as the most overpaid CEO at a public company in Minnesota.
In February 2013, Dave Dobson was named CEO.
In July 2018, Adam Coyle was named CEO with Mr. Dobson becoming Vice Chairman of the Board. Mr. Coyle had previously been on the board since 2015 and worked as an executive partner with Digital River's private equity owner, Siris Capital.
In January 2020, Christopher Bernander was named CFO. |
https://en.wikipedia.org/wiki/Fusarium%20venenatum | Fusarium venenatum is a microfungus of the genus Fusarium that has a high protein content. One of its strains is used commercially for the production of the single cell protein mycoprotein Quorn.
Fusarium venenatum was discovered growing in soil in Buckinghamshire in the United Kingdom, in 1967 by ICI as part of the effort during the 1960s to find alternative sources of food to fill the protein gap caused by the growing world population. It was originally misidentified as Fusarium graminearum.
The strain Fusarium venenatum A3/5 (IMI 145425, ATCC PTA-2684) was developed commercially by an ICI and Rank Hovis McDougall joint venture to derive a mycoprotein used as a food. Because the hyphae of the fungus are similar in length and width to animal muscle fibres the mycoprotein is used as an alternative to meat and is marketed as Quorn. It is also suitable as a substitute for fat in dairy products and a substitute for cereal in breakfast cereals and snacks.
Commercial production
Fusarium venenatum intended for use in Quorn products is grown under aerobic conditions in culture vessels by what is known as the 'Quorn Process'. The vessels are composed of two vertical cylinders around high, connected to one another at their top and bottom so as to form a continuous loop with a volume of about . Ports on the vessel allow the various ingredients involved to be added and removed. The culture broth is composed of 95% glucose, derived by the predigestion of maize starch. Potassium, magnesium and phosphate sources are added as a necessary mineral trace. Both these and the glucose are sterilized prior to use. Additional make up broth can be injected at the base of the vessel as material is removed. The broth is maintained at a pH of 6 and a temperature of 28–30 °C, with a biomass density of 15 grams per litre; equating to a total vessel biomass of 2,250 kg.
As culture growth occurs, carbon dioxide is produced and released through a vent at the top of the loop. A heat exchang |
https://en.wikipedia.org/wiki/Multi-agent%20planning | In computer science multi-agent planning involves coordinating the resources and activities of multiple agents.
NASA says, "multiagent planning is concerned with planning by (and for) multiple agents. It can involve agents planning for a common goal, an agent coordinating the plans (plan merging) or planning of others, or agents refining their own plans while negotiating over tasks or resources. The topic also involves how agents can do this in real time while executing plans (distributed continual planning). Multiagent scheduling differs from multiagent planning the same way planning and scheduling differ: in scheduling often the tasks that need to be performed are already decided, and in practice, scheduling tends to focus on algorithms for specific problem domains".
See also
Automated planning and scheduling
Distributed artificial intelligence
Cooperative distributed problem solving and Coordination
Multi-agent systems and Software agent and Self-organization
Multi-agent reinforcement learning
Task Analysis, Environment Modeling, and Simulation (TAEMS or TÆMS) |
https://en.wikipedia.org/wiki/Schwan%27s%20Company | Schwan's Company, formerly known as The Schwan Food Company, is a food company with approximately 7,500 employees. Having originated in the United States as a family-owned business, since 2019 the company has been a subsidiary of CJ CheilJedang of South Korea — with five major business units including Schwan's Consumer Brands, Schwan's Food Service, Strategic Partner Solutions and SFC Global Supply Chain. Schwan's Company no longer owns the home-delivery business that was known as Schwan's Home Service, which is currently rebranding to Yelloh.
The Schwan's family maintains 100 percent ownership of Minnesota-based Schwan’s Home Service, a privately held, independent entity traced to the company’s home-delivery business launched by Marvin Schwan in 1952. Schwan's Home Service sells frozen foods from home delivery trucks, in grocery store freezers, by mail, and to the food service industry.
Schwan's Company is widely known for its consumer brands, including Freschetta Pizza, Tony's Frozen Pizza, Mrs. Smith's Pies, Edwards Frozen Pies, Pagoda Egg Rolls, and Red Baron Pizza.
Corporate divisions
The company's major business units include Schwan's Consumer Brands, Schwan's Food Service, and SFC Global Supply Chain.
Schwan's Consumer Brands markets frozen food products in grocery stores primarily in the Western Hemisphere.
Schwan's Food Service markets and distributes frozen-food products to the food service industry.
SFC Global Supply Chain is a manufacturing cooperative that coordinates the company's production processes and helps develop new products.
Company history
In 1952, Marvin Schwan (1929–1993) began home delivery of his family's homemade ice cream (Schwan's Dairy and Dairy Lunch) to rural western Minnesota. Schwan's expanded to cover the Midwestern United States and made a number of acquisitions, including the Holiday Ice Cream Company and Russell Dairy. In 1957, the product line was expanded to include juice concentrates, and in 1962, Schwan's began |
https://en.wikipedia.org/wiki/Cheater%20bar | A cheater bar, snipe, or cheater pipe is an improvised breaker bar made from a length of pipe and a wrench (spanner).
Primary use
Cheater bars are usually used to free threaded pipe, screws, bolts, and other fasteners that are difficult to remove with a ratchet or pipe wrench alone. Cheater bars are also commonly used to operate valves.
When the handle of a pipe wrench, box wrench or ratchet is inserted into a cheater bar, the additional distance makes it possible to generate the required torque with the same amount of force being applied. However, the work done is the same with or without the cheater bar because the torque and angle of rotation needed to accomplish a particular task does not change.
The cheater bar allows higher torque with the same force by
A cheater bar is sometimes called a snipe, a pipe extension or an extension pipe.
Industrial safety problems
Problems in using such bars include:
All respected international and governmental safety organizations and enforcement agencies such as OSHA, MSHA, CCOHS, EU-OSHA, etc. strictly prohibit or vehemently discourage the use of cheater bars due to the extreme risk of injury or death to users and bystanders.
If the component frees suddenly, the worker can become a projectile that is propelled into whatever is in the "line-of-fire". This could (and has) resulted in falls, impacts, punctures, and other injuries.
The cheater bar itself can become part of a de facto catapult with the worker in the line-of-fire.
If the over-torqueing results in the failure of any of the items in the jury rig, the fragments can injure workers in the line-of-fire.
The use of the cheater bar can result in component damage that can, in turn, harm workers.
Pump or fluid transport equipment problems
Ports of pumps can be damaged resulting in:
The outlet or inlet ports can be warped.
The pump casting or manifold can crack and then leak.
Some organizations forbid their use. For example, NASA is one such organization:
"Use th |
https://en.wikipedia.org/wiki/Slitherlink | Slitherlink (also known as Fences, Takegaki, Loop the Loop, Loopy, Ouroboros, Suriza, Rundweg and Dotty Dilemma) is a logic puzzle developed by publisher Nikoli.
Rules
Slitherlink is played on a rectangular lattice of dots. Some of the squares formed by the dots have numbers inside them. The objective is to connect horizontally and vertically adjacent dots so that the lines form a simple loop with no loose ends. In addition, the number inside a square represents how many of its four sides are segments in the loop.
Other types of planar graphs can be used in lieu of the standard grid, with varying numbers of edges per vertex or vertices per polygon. These patterns include snowflake, Penrose, Laves and Altair tilings. These add complexity by varying the number of possible paths from an intersection, and/or the number of sides to each polygon; but similar rules apply to their solution.
Solution methods
Notation
Whenever the number of lines around a cell matches the number in the cell, the other potential lines must be eliminated. This is usually indicated by marking an X on lines known to be empty.
Another useful notation when solving Slitherlink is a ninety degree arc between two adjacent lines, to indicate that exactly one of the two must be filled. A related notation is a double arc between adjacent lines, indicating that both or neither of the two must be filled. These notations are not necessary to the solution, but can be helpful in deriving it.
Many of the methods below can be broken down into two simpler steps by use of arc notation.
Exactly 2 or 0 lines at each point
A key to many deductions in Slitherlink is that every point has either exactly two lines connected to it, or no lines. So if a point which is in the centre of the grid, not at an edge or corner, has three incoming lines which are X'd out, the fourth must also be X'd out. This is because the point cannot have just one line - it has no exit route from that point. Similarly, if a point on the |
https://en.wikipedia.org/wiki/Yuri%20Matiyasevich | Yuri Vladimirovich Matiyasevich, (; born 2 March 1947 in Leningrad) is a Russian mathematician and computer scientist. He is best known for his negative solution of Hilbert's tenth problem (Matiyasevich's theorem), which was presented in his doctoral thesis at LOMI (the Leningrad Department of the Steklov Institute of Mathematics).
Biography
Early years and education
Yuri Matiyasevich was born in Leningrad on March 2, 1947. The first few classes he studied at school No. 255 with Sofia G. Generson, thanks to whom he became interested in mathematics. In 1961 he began to participate in all-Russian olympiads. From 1962 to 1963 he studied at Leningrad physical and mathematical school No. 239. Also from 7th to 9th grade he was involved in the mathematical circle of the Leningrad Palace of Pioneers. In 1963-1964 he completed 10th grade at the Moscow State University physics and mathematics boarding school No. 18 named after A. N. Kolmogorov.
In 1964, he won a gold medal the International Mathematical Olympiad and was enrolled in the Mathematics and Mechanics Department of St. Petersburg State University without exams. He took his high school diploma exams as a first-year student.
Being a second-year student, he released two papers in mathematical logic that were published in the Proceedings of the USSR Academy of Sciences. He presented these works at the International Congress of Mathematicians in 1966.
After graduation, he enrolled in graduate school at St. Petersburg Department of Steklov Mathematical Institute of the Russian Academy of Sciences (POMI). In 1970, under the guidance of , he defended his thesis for the degree of Candidate of Sciences in Physics and Mathematics.
In 1972, at the age of 25, he defended his doctoral dissertation on the unsolvability of Hilbert's tenth problem.
From 1974 Matiyasevich worked in scientific positions at LOMI, first as a senior researcher, in 1980 he headed the Laboratory of Mathematical Logic. In 1995, Matiyasevich became |
https://en.wikipedia.org/wiki/History%20of%20optics | Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, followed by theories on light and vision developed by ancient Greek philosophers, and the development of geometrical optics in the Greco-Roman world. The word optics is derived from the Greek term meaning 'appearance, look'. Optics was significantly reformed by the developments in the medieval Islamic world, such as the beginnings of physical and physiological optics, and then significantly advanced in early modern Europe, where diffractive optics began. These earlier studies on optics are now known as "classical optics". The term "modern optics" refers to areas of optical research that largely developed in the 20th century, such as wave optics and quantum optics.
Early history
In the fifth century BCE, Empedocles postulated that everything was composed of four elements; fire, air, earth and water. He believed that Aphrodite made the human eye out of the four elements and that she lit the fire in the eye which shone out from the eye making sight possible. If this were true, then one could see during the night just as well as during the day, so Empedocles postulated an interaction between rays from the eyes and rays from a source such as the sun. He stated that light has a finite speed.
Separate considerable developments in optics were also achieved in ancient China.
In his Optics Greek mathematician Euclid observed that "things seen under a greater angle appear greater, and those under a lesser angle less, while those under equal angles appear equal". In the 36 propositions that follow, Euclid relates the apparent size of an object to its distance from the eye and investigates the apparent shapes of cylinders and cones when viewed from different angles. Pappus believed these results to be important in astronomy and included Euclid's Optics, along with his Phaenomena, in the Little Astronomy, a compendium of smaller works to be studied before the Syntaxis (Almagest) of Ptolem |
https://en.wikipedia.org/wiki/History%20of%20the%20Actor%20model | In computer science, the Actor model, first published in 1973, is a mathematical model of concurrent computation.
Event orderings versus global state
A fundamental challenge in defining the Actor model is that it did not provide for global states so that a computational step could not be defined as going from one global state to the next global state as had been done in all previous models of computation.
In 1963 in the field of Artificial Intelligence, John McCarthy introduced situation variables in logic in the Situational Calculus. In McCarthy and Hayes 1969, a situation is defined as "the complete state of the universe at an instant of time." In this respect, the situations of McCarthy are not suitable for use in the Actor model since it has no global states.
From the definition of an Actor, it can be seen that numerous events take place: local decisions, creating Actors, sending messages, receiving messages, and designating how to respond to the next message received. Partial orderings on such events have been axiomatized in the Actor model and their relationship to physics explored (see Actor model theory).
Relationship to physics
According to Hewitt (2006), the Actor model is based on physics in contrast with other models of computation that were based on mathematical logic, set theory, algebra, etc. Physics influenced the Actor model in many ways, especially quantum physics and relativistic physics. One issue is what can be observed about Actor systems. The question does not have an obvious answer because it poses both theoretical and observational challenges similar to those that had arisen in constructing the foundations of quantum physics. In concrete terms for Actor systems, typically we cannot observe the details by which the arrival order of messages for an Actor is determined (see Indeterminacy in concurrent computation). Attempting to do so affects the results and can even push the indeterminacy elsewhere. e.g., see metastability in electronics. |
https://en.wikipedia.org/wiki/Sphericity | Sphericity is a measure of how closely the shape of an object resembles that of a perfect sphere. For example, the sphericity of the balls inside a ball bearing determines the quality of the bearing, such as the load it can bear or the speed at which it can turn without failing. Sphericity is a specific example of a compactness measure of a shape. Defined by Wadell in 1935, the sphericity, , of an object is the ratio of the surface area of a sphere with the same volume to the object's surface area:
where is volume of the object and is the surface area. The sphericity of a sphere is unity by definition and, by the isoperimetric inequality, any shape which is not a sphere will have sphericity less than 1.
Sphericity applies in three dimensions; its analogue in two dimensions, such as the cross sectional circles along a cylindrical object such as a shaft, is called roundness.
Ellipsoidal objects
The sphericity, , of an oblate spheroid (similar to the shape of the planet Earth) is:
where a and b are the semi-major and semi-minor axes respectively.
Derivation
Hakon Wadell defined sphericity as the surface area of a sphere of the same volume as the particle divided by the actual surface area of the particle.
First we need to write surface area of the sphere, in terms of the volume of the object being measured,
therefore
hence we define as:
Sphericity of common objects
See also
Equivalent spherical diameter
Flattening
Isoperimetric ratio
Rounding (sediment)
Roundness
Willmore energy |
https://en.wikipedia.org/wiki/Open%20Enterprise%20Server | Open Enterprise Server (OES) is a server operating system published by Novell in March 2005 to succeed their NetWare product.
Unlike NetWare, Novell OES is a Linux distribution—specifically, one based on SUSE Linux Enterprise Server. The first major release of Open Enterprise Server (OES 1) could run either with a Linux kernel (with a NetWare compatibility layer) or Novell's NetWare kernel (with a Linux compatibility layer). Novell discontinued the NetWare kernel prior to the release of OES 2, but NetWare 6.5 SP7, and later SP8 can run as a paravirtualized guest inside the Xen hypervisor (Officially supported until 7 March 2012, Novell self-supported until 7 March 2015).
OES 1 and OES 2
Novell released OES 1, the first version of OES, on 25 March 2005. Since some users wanted backward compatibility with NetWare, Novell offered two installation options: OES-NetWare and OES-Linux. These are two different operating systems with different kernels and different userlands.
OES-NetWare is NetWare v6.5 equipped with NetWare Loadable Modules for various Novell services (such as NetWare Core Protocol, Novell eDirectory, Novell Storage Services, and iPrint) and open-source software (such as OpenSSH, Apache Tomcat, and the Apache HTTP Server).
OES-Linux is based on the SUSE Linux Enterprise Server (SLES) with added NetWare services ported to the Linux kernel: e.g. the NetWare Core Protocol, Novell eDirectory, Novell Storage Services, and iPrint.
Novell released OES 2, the second version of OES, on 12 October 2007. It was the first SLES-Linux-kernel-only OES, but it retained the OES-NetWare operating system option, as NetWare 6.5 SP7 can run as a paravirtualized guest inside the Xen hypervisor. The SLES base of the OES 2 was later updated to SLES 10 SP1.
Features introduced in OES 2 include:
32-bit system or 64-bit system supporting 64 bit and 32 bit applications
Hardware virtualization
Dynamic Storage Technology, which provides Novell Shadow Volumes
Windows domain se |
https://en.wikipedia.org/wiki/Total%20expense%20ratio | The total expense ratio (TER) is a measure of the total cost of a fund to an investor. Total costs may include various fees (purchase, redemption, auditing) and other expenses. The TER, calculated by dividing the total annual cost by the fund's total assets averaged over that year, is denoted as a percentage. It will normally vary somewhat from year to year.
Typically it consists of the annual management charge (AMC), the fee that the fund company charges annually to manage the fund (typically commission paid to fund managers), plus 'other' charges incurred with running the fund. These other charges can consist of share registration fees, fees payable to auditors, legal fees, and custodian fees. Not included in the total expense ratio are transaction costs as a result of trading of the fund's assets.
Because the TER is inclusive of these other charges, it is a more accurate measure of the 'drag' on a fund's performance than just using the annual management charge alone. In their advertisements and even their fact sheets, fund companies tend to give more emphasis to the AMC, making it difficult for a private investor (in the UK at least) to see the total expense ratio of the fund they are investing in. In the United States, however, it is mandatory not only to show it but also to make it as clear and as concise as possible.
Fund costs are very important: every dollar charged by a fund is a dollar that investors won't get, but costs can be offset to some extent – or even completely – by benefits.
Fund managers can benefit investors in a range of ways. These include:
investing in assets that smaller direct investors cannot access;
paying lower brokerage costs for buying and selling;
using a range of risk reducing techniques, such as managing levels of hedging in foreign exchange exposure; and
taking advantage of managing a large pool of assets – often with regular inflows – to make ongoing adjustments to the fund efficiently and in ways that enhance returns, |
https://en.wikipedia.org/wiki/Rossby%20radius%20of%20deformation | In atmospheric dynamics and physical oceanography, the Rossby radius of deformation is the length scale at which rotational effects become as important as buoyancy or gravity wave effects in the evolution of the flow about some disturbance.
For a barotropic ocean, the Rossby radius is , where is the gravitational acceleration, is the water depth, and is the Coriolis parameter.
For f = 1×10−4 s−1 appropriate to 45° latitude, g = 9.81 m/s2 and D = 4 km, LR ≈ 2000 km; using the same latitude and gravity but changing D to 40 m; LR ≈ 200 km.
The nth baroclinic Rossby radius is:
, where is the Brunt–Väisälä frequency, is the scale height, and n = 1, 2, ....
In Earth's atmosphere, the ratio N/f0 is typically of order 100, so the Rossby radius is about 100 times the vertical scale height, H. For a vertical scale associated with the height of the tropopause, LR, 1 ≈ 1000 km, which is the predominant scale seen on weather charts for cyclones and anticyclones. This is commonly called the synoptic scale.
In the ocean, the Rossby radius varies dramatically with latitude. Near the equator it is larger than 200 km, while in the high latitude regions it is less than 10 km. The size of ocean eddies varies similarly; in low latitude regions, near the equator, eddies are much larger than in high latitude regions.
The associated dimensionless parameter is the Rossby number. Both are named in honor of Carl-Gustav Rossby. |
https://en.wikipedia.org/wiki/Le%20Cam%27s%20theorem | In probability theory, Le Cam's theorem, named after Lucien Le Cam (1924 – 2000), states the following.
Suppose:
are independent random variables, each with a Bernoulli distribution (i.e., equal to either 0 or 1), not necessarily identically distributed.
(i.e. follows a Poisson binomial distribution)
Then
In other words, the sum has approximately a Poisson distribution and the above inequality bounds the approximation error in terms of the total variation distance.
By setting pi = λn/n, we see that this generalizes the usual Poisson limit theorem.
When is large a better bound is possible: , where represents the operator.
It is also possible to weaken the independence requirement. |
https://en.wikipedia.org/wiki/Normal%20scheme | In algebraic geometry, an algebraic variety or scheme X is normal if it is normal at every point, meaning that the local ring at the point is an integrally closed domain. An affine variety X (understood to be irreducible) is normal if and only if the ring O(X) of regular functions on X is an integrally closed domain. A variety X over a field is normal if and only if every finite birational morphism from any variety Y to X is an isomorphism.
Normal varieties were introduced by .
Geometric and algebraic interpretations of normality
A morphism of varieties is finite if the inverse image of every point is finite and the morphism is proper. A morphism of varieties
is birational if it restricts to an isomorphism between dense open subsets. So, for example, the cuspidal cubic curve X in the affine plane A2 defined by x2 = y3 is not normal, because there is a finite birational morphism A1 → X
(namely, t maps to (t3, t2)) which is not an isomorphism. By contrast, the affine line A1 is normal: it cannot be simplified any further by finite birational morphisms.
A normal complex variety X has the property, when viewed as a stratified space using the classical topology, that every link is connected. Equivalently, every complex point x has arbitrarily small neighborhoods U such that U minus
the singular set of X is connected. For example, it follows that the nodal cubic curve X in the figure, defined by x2 = y2(y + 1), is not normal. This also follows from the definition of normality, since there is a finite birational morphism from A1 to X which is not an isomorphism; it sends two points of A1 to the same point in X.
More generally, a scheme X is normal if each of its local rings
OX,x
is an integrally closed domain. That is, each of these rings is an integral domain R, and every ring S with R ⊆ S ⊆ Frac(R) such that S is finitely generated as an R-module is equal to R. (Here Frac(R) denotes the field of fractions of R.) This is a direct translation, in terms of local rin |
https://en.wikipedia.org/wiki/Depurination | Depurination is a chemical reaction of purine deoxyribonucleosides, deoxyadenosine and deoxyguanosine, and ribonucleosides, adenosine or guanosine, in which the β-N-glycosidic bond is hydrolytically cleaved releasing a nucleic base, adenine or guanine, respectively. The second product of depurination of deoxyribonucleosides and ribonucleosides is sugar, 2'-deoxyribose and ribose, respectively. More complex compounds containing nucleoside residues, nucleotides and nucleic acids, also suffer from depurination. Deoxyribonucleosides and their derivatives are substantially more prone to depurination than their corresponding ribonucleoside counterparts. Loss of pyrimidine bases (cytosine and thymine) occurs by a similar mechanism, but at a substantially lower rate.
When depurination occurs with DNA, it leads to the formation of apurinic site and results in an alteration of the structure. Studies estimate that as many as 5,000 purines are lost this way each day in a typical human cell. In cells, one of the main causes of depurination is the presence of endogenous metabolites undergoing chemical reactions. Apurinic sites in double-stranded DNA are efficiently repaired by portions of the base excision repair (BER) pathway. Depurinated bases in single-stranded DNA undergoing replication can lead to mutations, because in the absence of information from the complementary strand, BER can add an incorrect base at the apurinic site, resulting in either a transition or transversion mutation.
Depurination is known to play a major role in cancer initiation.
Hydrolytic depurination is one of the principal forms of damage to ancient DNA in fossil or subfossil material, since the base remains unrepaired. This results in both loss of information (the base sequence), and difficulties in recovery and in vitro replication of the damaged molecule by the polymerase chain reaction.
Chemistry of the reaction
Depurination is not uncommon because purine is a good leaving group via the 9N-nitr |
https://en.wikipedia.org/wiki/Spin%20wave | In condensed matter physics, a spin wave is a propagating disturbance in the ordering of a magnetic material. These low-lying collective excitations occur in magnetic lattices with continuous symmetry. From the equivalent quasiparticle point of view, spin waves are known as magnons, which are bosonic modes of the spin lattice that correspond roughly to the phonon excitations of the nuclear lattice. As temperature is increased, the thermal excitation of spin waves reduces a ferromagnet's spontaneous magnetization. The energies of spin waves are typically only in keeping with typical Curie points at room temperature and below.
Theory
The simplest way of understanding spin waves is to consider the Hamiltonian for the Heisenberg ferromagnet:
where is the exchange energy, the operators represent the spins at Bravais lattice points, is the Landé -factor, is the Bohr magneton and is the internal field which includes the external field plus any "molecular" field. Note that in the classical continuum case and in dimensions the Heisenberg ferromagnet equation has the form
In and dimensions this equation admits several integrable and non-integrable extensions like the Landau-Lifshitz equation, the Ishimori equation and so on. For a ferromagnet and the ground state of the Hamiltonian is that in which all spins are aligned parallel with the field . That is an eigenstate of can be verified by rewriting it in terms of the spin-raising and spin-lowering operators given by:
resulting in
where has been taken as the direction of the magnetic field. The spin-lowering operator annihilates the state with minimum projection of spin along the -axis, while the spin-raising operator annihilates the ground state with maximum spin projection along the -axis. Since
for the maximally aligned state, we find
where N is the total number of Bravais lattice sites. The proposition that the ground state is an eigenstate of the Hamiltonian is confirmed.
One might guess that the |
https://en.wikipedia.org/wiki/Feature%20connector | The feature connector was an internal connector found mostly in some older ISA, VESA Local Bus, and PCI graphics cards, but also on some early AGP ones. It was intended for use by devices which needed to exchange large amounts of data with the graphics card without hogging a computer system's CPU or data bus, such as TV tuner cards, video capture cards, MPEG video decoders (e.g. RealMagic), and first generation 3D graphic accelerator cards. Early examples include the IBM EGA video adapter.
Several standards existed for feature connectors, depending on the bus and graphics card type. Most of them were simply an 8, 16 or 32-bit wide internal connector, transferring data between the graphics card and another device, bypassing the system's CPU and memory completely.
Their speeds often far exceeded the speed of normal ISA or even early PCI buses, e.g. 40 MByte/s for a standard ISA-based SVGA, up to 150 MByte/s for a VESA-based or PCI-based one, while the standard 16 bit ISA bus ran at ~5.3 MByte/s and the VESA bus at up to 160 MByte/s bandwidth. The Feature connector bandwidths were far beyond the capabilities of e.g. a 386, 486 and barely handled by an early Pentium.
Depending on the implementation, it could be uni or bi-directional, and carry analog color information as well as data. Unlike analog overlay devices however, a feature connector carried mainly data and essentially allowed an expansion card to access the graphics card Video RAM directly, although directing this data stream to the system's CPU and RAM was not always possible, limiting its usefulness mainly to display purposes.
Although its use rapidly declined after the introduction of the faster AGP internal bus, it was, at its time, the only feasible way to connect certain types of graphics-intensive devices to an average computing system without exceeding the available CPU power and memory bandwidth, and without the disadvantages and limitations of a purely analog overlay.
The idea of accessing a vi |
https://en.wikipedia.org/wiki/Acoustic%20wave%20equation | In physics, the acoustic wave equation is a second-order partial differential equation that governs the propagation of acoustic waves through a material medium resp. a standing wavefield. The equation describes the evolution of acoustic pressure or particle velocity as a function of position and time . A simplified (scalar) form of the equation describes acoustic waves in only one spatial dimension, while a more general form describes waves in three dimensions. Propagating waves in a pre-defined direction can also be calculated using first order one-way wave equation.
For lossy media, more intricate models need to be applied in order to take into account frequency-dependent attenuation and phase speed. Such models include acoustic wave equations that incorporate fractional derivative terms, see also the acoustic attenuation article or the survey paper.
In one dimension
Equation
The wave equation describing a standing wave field in one dimension (position ) is
where is the acoustic pressure (the local deviation from the ambient pressure), and where is the speed of sound.
Solution
Provided that the speed is a constant, not dependent on frequency (the dispersionless case), then the most general solution is
where and are any two twice-differentiable functions. This may be pictured as the superposition of two waveforms of arbitrary profile, one () traveling up the x-axis and the other () down the x-axis at the speed . The particular case of a sinusoidal wave traveling in one direction is obtained by choosing either or to be a sinusoid, and the other to be zero, giving
.
where is the angular frequency of the wave and is its wave number.
Derivation
The derivation of the wave equation involves three steps: derivation of the equation of state, the linearized one-dimensional continuity equation, and the linearized one-dimensional force equation.
The equation of state (ideal gas law)
In an adiabatic process, pressure P as a function of density |
https://en.wikipedia.org/wiki/Ferulic%20acid | Ferulic acid is a hydroxycinnamic acid, is an organic compound with the formula (CH3O)HOC6H3CH=CHCO2H. The name is derived from the genus Ferula, referring to the giant fennel (Ferula communis). Classified as a phenolic phytochemical, ferulic acid is an amber colored solid. Esters of ferulic acid are found in plant cell walls, covalently bonded to hemicellulose such as arabinoxylans. Salts and esters derived from ferulic acid are called ferulates.
Occurrence in nature
As a building block of lignocelluloses, such as pectin and lignin, ferulic acid is ubiquitous in the plant kingdom, including a number of vegetable sources. It occurs in particularly high concentrations in popcorn and bamboo shoots. It is a major metabolite of chlorogenic acids in humans along with caffeic and isoferulic acid, and is absorbed in the small intestine, whereas other metabolites such as dihydroferulic acid, feruloylglycine and dihydroferulic acid sulfate are produced from chlorogenic acid in the large intestine by the action of gut flora.
In cereals, ferulic acid is localized in the bran – the hard outer layer of grain. In wheat, phenolic compounds are mainly found in the form of insoluble bound ferulic acid and may be relevant to resistance to wheat fungal diseases. The highest known concentration of ferulic acid glucoside has been found in flaxseed (). It is also found in barley grain.
Asterid eudicot plants can also produce ferulic acid. The tea brewed from the leaves of yacón (Smallanthus sonchifolius), a plant traditionally grown in the northern and central Andes, contains quantities of ferulic acid. In legumes, the white bean variety navy bean is the richest source of ferulic acid among the common bean (Phaseolus vulgaris) varieties. It is also found in horse grams (Macrotyloma uniflorum).
Although there are many sources of ferulic acid in nature, its bioavailability depends on the form in which it is present: free ferulic acid has limited solubility in water, and hence po |
https://en.wikipedia.org/wiki/Visual%20angle | Visual angle is the angle a viewed object subtends at the eye, usually stated in degrees of arc.
It also is called the object's angular size.
The diagram on the right shows an observer's eye looking at a frontal extent (the vertical arrow) that has a linear size , located in the distance from point .
For present purposes, point can represent the eye's nodal points at about the center of the lens, and also represent the center of the eye's entrance pupil that is only a few millimeters in front of the lens.
The three lines from object endpoint heading toward the eye indicate the bundle of light rays that pass through the cornea, pupil and lens to form an optical image of endpoint on the retina at point .
The central line of the bundle represents the chief ray.
The same holds for object point and its retinal image at .
The visual angle is the angle between the chief rays of and .
Measuring and computing
The visual angle can be measured directly using a theodolite placed at point .
Or, it can be calculated (in radians) using the formula, .
However, for visual angles smaller than about 10 degrees, this simpler formula provides very close approximations:
The retinal image and visual angle
As the above sketch shows, a real image of the object is formed on the retina between points and . (See visual system). For small angles, the size of this retinal image is
where is the distance from the nodal points to the retina, about 17 mm.
Examples
If one looks at a one-centimeter object at a distance of one meter and a two-centimeter object at a distance of two meters, both subtend the same visual angle of about 0.01 rad or 0.57°. Thus they have the same retinal image size .
That is just a bit larger than the retinal image size for the moon, which is about , because, with moon's mean diameter , and earth to moon mean distance averaging (), .
Also, for some easy observations, if one holds one's index finger at arm's length, the width of the index |
https://en.wikipedia.org/wiki/Brunt%E2%80%93V%C3%A4is%C3%A4l%C3%A4%20frequency | In atmospheric dynamics, oceanography, asteroseismology and geophysics, the Brunt–Väisälä frequency, or buoyancy frequency, is a measure of the stability of a fluid to vertical displacements such as those caused by convection. More precisely it is the frequency at which a vertically displaced parcel will oscillate within a statically stable environment. It is named after David Brunt and Vilho Väisälä. It can be used as a measure of atmospheric stratification.
Derivation for a general fluid
Consider a parcel of water or gas that has density . This parcel is in an environment of other water or gas particles where the density of the environment is a function of height: . If the parcel is displaced by a small vertical increment , and it maintains its original density, so that its volume does not change, it will be subject to an extra gravitational force against its surroundings of:
where is the gravitational acceleration, and is defined to be positive. We make a linear approximation to , and move to the RHS:
The above second-order differential equation has straightforward solutions of:
where the Brunt–Väisälä frequency is:
For negative , the displacement has oscillating solutions (and N gives our angular frequency). If it is positive, then there is run away growth – i.e. the fluid is statically unstable.
In meteorology and astrophysics
For a gas parcel, the density will only remain fixed as assumed in the previous derivation if the pressure, , is constant with height, which is not true in an atmosphere confined by gravity. Instead, the parcel will expand adiabatically as the pressure declines. Therefore a more general formulation used in meteorology is:
, where is potential temperature, is the local acceleration of gravity, and is geometric height.
Since , where is a constant reference pressure, for a perfect gas this expression is equivalent to:
,
where in the last form , the adiabatic index. Using the ideal gas law, we can eliminate the temperature |
https://en.wikipedia.org/wiki/DNP3 | Distributed Network Protocol 3 (DNP3) is a set of communications protocols used between components in process automation systems. Its main use is in utilities such as electric and water companies. Usage in other industries is not common. It was developed for communications between various types of data acquisition and control equipment. It plays a crucial role in SCADA systems, where it is used by SCADA Master Stations (a.k.a. Control Centers), Remote Terminal Units (RTUs), and Intelligent Electronic Devices (IEDs). It is primarily used for communications between a master station and RTUs or IEDs. ICCP, the Inter-Control Center Communications Protocol (a part of IEC 60870-6), is used for inter-master station communications. Competing standards include the older Modbus protocol and the newer IEC 61850 protocol.
History
While IEC 60870-5 was still under development and had not been standardized, there was a need to create a standard that would allow interoperability between various vendors' SCADA components for the electrical grid. Thus, in 1993, GE-Harris Canada (formerly known as Westronic) used the partially completed IEC 60870-5 protocol specifications as the basis for an open and immediately implementable protocol that specifically catered to North American requirements. The protocol is designed to allow reliable communications in the adverse environments that electric utility automation systems are subjected to, being specifically designed to overcome distortion induced by electromagnetic interference (EMI), aging components (their expected lifetimes may stretch into decades), and poor transmission media.
Security
Because smart grid applications generally assume access by third parties to the same physical networks and underlying IP infrastructure of the grid, much work has been done to add Secure Authentication features to the DNP3 protocol. The DNP3 protocol is compliant with IEC 62351-5. Some vendors support encryption via bump-in-the-wire for seri |
https://en.wikipedia.org/wiki/Lightface%20analytic%20game | In descriptive set theory, a lightface analytic game is a game whose payoff set A is a subset of Baire space; that is, there is a tree T on which is a computable subset of , such that A is the projection of the set of all branches of T.
The determinacy of all lightface analytic games is equivalent to the existence of 0#.
Effective descriptive set theory
Determinacy |
https://en.wikipedia.org/wiki/ANU%20Research%20School%20of%20Physics | The Research School of Physics (RSPhys) was established with the creation of the Australian National University (ANU) in 1947. Located at the ANU's main campus in Canberra, the school is one of the four founding research schools in the ANU's Institute of Advanced Studies.
As part of the Institute of Advanced Studies it is primarily a research school with limited interaction with the ANU's undergraduate students. With a total of around 200 employees the school has approximately 60 PhD students and 70 academic staff. The school is divided into separate research departments although PhD students can often be based in more than one department.
Research
RSPhys is one of the leading physics research institutions in Australia. Major research facilities at the school include the 14UD NEC Pelletron accelerator and associated modular superconducting linac run by the Department of Nuclear Physics, the H-1NF flexible Stellarator Heliac run by the Plasma Research Laboratory plus an extensive range of smaller experimental and computational equipment.
Research ranges from the fundamental to the applied, including both experimental and theoretical work. The school's primary research areas are: materials science and engineering; lasers, nonlinear optics and photonics; nanotechnology and mesoscopic physics; physics of atoms, molecules and the nucleus; plasma physics and surface science; physics and the environment.
The nuclear physics 14UD is one of a handful of large Van de Graaff accelerators in the world. It was the largest machine of its type when installed in 1974. After many upgrades the 14UD is capable of running terminal voltage of up 16.7 MV. Charging is via three inductive charging chains. In 1996 a superconducting RF linac was installed that is used as an energy booster for the 14UD enabling higher energies to be reached.
History
Sir Mark Oliphant was the founder of the school and its first director from 1950 to 1963. The school was originally called the "Research Sc |
https://en.wikipedia.org/wiki/Fanning%20friction%20factor | The Fanning friction factor, named after John Thomas Fanning, is a dimensionless number used as a local parameter in continuum mechanics calculations. It is defined as the ratio between the local shear stress and the local flow kinetic energy density:
where:
is the local Fanning friction factor (dimensionless)
is the local shear stress (unit in or or Pa)
is the bulk flow velocity (unit in or )
is the density of the fluid (unit in or )
In particular the shear stress at the wall can, in turn, be related to the pressure loss by multiplying the wall shear stress by the wall area ( for a pipe with circular cross section) and dividing by the cross-sectional flow area ( for a pipe with circular cross section). Thus
Fanning friction factor formula
This friction factor is one-fourth of the Darcy friction factor, so attention must be paid to note which one of these is meant in the "friction factor" chart or equation consulted. Of the two, the Fanning friction factor is the more commonly used by chemical engineers and those following the British convention.
The formulas below may be used to obtain the Fanning friction factor for common applications.
The Darcy friction factor can also be expressed as
where:
is the shear stress at the wall
is the density of the fluid
is the flow velocity averaged on the flow cross section
For laminar flow in a round tube
From the chart, it is evident that the friction factor is never zero, even for smooth pipes because of some roughness at the microscopic level.
The friction factor for laminar flow of Newtonian fluids in round tubes is often taken to be:
where Re is the Reynolds number of the flow.
For a square channel the value used is:
For turbulent flow in a round tube
Hydraulically smooth piping
Blasius developed an expression of friction factor in 1913 for the flow in the regime .
Koo introduced another explicit formula in 1933 for a turbulent flow in region of
Pipes/tubes of general roughness
When th |
https://en.wikipedia.org/wiki/Online%20counseling | Online counseling is a form of professional mental health counseling that is generally performed through the internet. Computer aided technologies are used by the trained professional counselors and individuals seeking counseling services to communicate rather than conventional face-to-face interactions. Online counseling is also referred to as teletherapy, e-therapy, cyber therapy, or web counseling. Services are typically offered via email, real-time chat, and video conferencing. Some clients use online counseling in conjunction with traditional psychotherapy, or nutritional counseling. An increasing number of clients are using online counseling as a replacement for office visits.
While some forms of telepsychology and telepsychiatry have been available for over 35 years, the development of internet video chat systems and the continued increase of the market penetration for the broadband has resulted in the continuing growth of online therapy. Some clients are using videoconferencing, live chat and email services with a mental health professional in place of or in addition to face-to-face meetings.
History
One of the first demonstrations of the Internet was a simulated psychotherapy session between computers at Stanford and UCLA during the International Conference on Computer Communication in October 1972. Although this was a simulation and not actual counseling, the demonstration created an interest in the potential of online communication for counseling. As access to the internet, bulletin boards, and online services became more available in the 1980s, and online communication became more common, virtual self-help groups naturally developed. These self-help groups may be considered a precursor to online counseling. When the World Wide Web became public in the early 1990s and mental health professionals began to create websites offering mental health information, some began to receive requests for personal help and started to respond to these requests, leadin |
https://en.wikipedia.org/wiki/Sennit | Sennit is a type of cordage made by plaiting strands of dried fibre or grass. It can be used ornamentally in crafts, like a kind of macramé, or to make straw hats. Sennit is an important material in the cultures of Oceania, where it is used in traditional architecture, boat building, fishing and as an ornamentation.
Oceania
Tonga
Sennit in Tonga is called kafa.
Fiji
The Fijian term used is magimagi, a craft product of the Fiji Islands.
Hawai'i
The term is also used in Hawaii and throughout Polynesia for cordage made by braiding the fibers of coconut husks. It was important in attaching the ama (outrigger float) via the iako (spars) to the hull of canoes, stones to war-club handles, erecting hale (houses), etc.
Samoa
In the Samoan language, sennit is called afa. It was used as cordage in the construction of traditional Samoan architecture, boat building with many other functional uses. Afa is handmade from dried coconut fibre from the husk of certain varieties of coconuts with long fibres, particularly the niu'afa (afa palm).
Sennit is mentioned in Robert Gibbings book Over the Reefs (1948). He refers to its use in Samoa in 1946, where he was able to observe its being made on many occasions. He notes that its crafting was a constant occupation in Samoan villages, because so much of the material was required. A significant quote from the book, made by a village chief to Gibbings, emphasises the importance of sennit in Samoan culture: "In your country," said a chief to me, "only a few men can make nails, but in Samoa, everyone can make nails" (p. 118). He was referring to the sennit that is used to bind the structures or huts in which they lived. Sennit had a variety of other uses, including in shark fishing, where it was used as a noose that was placed over the shark's head as it came alongside the canoe.
"They showed me the sennit noose they had used—five years old and as good as new. They said it would last another five years if cared for." Robert Gribbings |
https://en.wikipedia.org/wiki/Eva%20Jablonka | Eva Jablonka () (born 1952) is an Israeli evolutionary theorist and geneticist, known especially for her interest in epigenetic inheritance. Born in 1952 in Poland, she emigrated to Israel in 1957. She is a professor at the Cohn Institute for the History of Philosophy of Science and Ideas at Tel Aviv University. In 1981 she was awarded the Landau prize of Israel for outstanding Master of Science (M.Sc.) work and in 1988, the Marcus prize for outstanding Ph.D. work. She is a proponent of academic freedom, recognising that on such matters, "academic and political issues cannot really be kept apart", although she is not a proponent of simplistic solutions, and shows a preference to describe her own position.
Work on evolutionary themes
Jablonka publishes about evolutionary themes, especially epigenetics. Her emphasis on non-genetic forms of evolution has received interest from those attempting to expand the scope of evolutionist thinking into other spheres. Jablonka has been described as being in the vanguard of an ongoing revolution within evolutionary biology, and is a leading proponent of the extended evolutionary synthesis.
Her first book on the subject of epigenetics, Epigenetic Inheritance and Evolution: the Lamarckian Dimension (1995), was co-authored with Marion Lamb. Her book Animal Traditions (2000), co-authored with Eytan Avital, extended models of human cultural transmission to the non-human animal world, to show that cultural evolution has played an important role in the evolution of other animals. Jablonka again co-authored with Lamb on Evolution in Four Dimensions (2005). Building on the approach of evolutionary developmental biology, and recent findings of molecular and behavioral biology, they argue the case for the transmission of not just genes per se, but heritable variations transmitted from generation to generation by whatever means. They suggest that such variation can occur at four levels. Firstly, at the established physical level of genetic |
https://en.wikipedia.org/wiki/Screen%20tearing | Screen tearing is a visual artifact in video display where a display device shows information from multiple frames in a single screen draw.
The artifact occurs when the video feed to the device is not synchronized with the display's refresh rate. That can be caused by non-matching refresh rates, and the tear line then moves as the phase difference changes (with speed proportional to the difference of frame rates). It can also occur simply from a lack of synchronization between two equal frame rates, and the tear line is then at a fixed location that corresponds to the phase difference. During video motion, screen tearing creates a torn look as the edges of objects (such as a wall or a tree) fail to line up.
Tearing can occur with most common display technologies and video cards and is most noticeable in horizontally-moving visuals, such as in slow camera pans in a movie or classic side-scrolling video games.
Screen tearing is less noticeable when more than two frames finish rendering during the same refresh interval since that means the screen has several narrower tears, instead of a single wider one.
Prevention
Ways to prevent video tearing depend on the display device and video card technology, the software in use, and the nature of the video material. The most common solution is to use multiple buffering.
Most systems use multiple buffering and some means of synchronization of display and video memory refresh cycles.
Vertical synchronization
A vertical synchronization is an option in most systems in which the video card is prevented from doing anything visible to the display memory until after the monitor finishes its current refresh cycle.
During the vertical blanking interval, the driver orders the video card to either rapidly copy the off-screen graphics area into the active display area (double buffering), or treat both memory areas as displayable, and simply switch back and forth between them (page flipping).
Nvidia and AMD video adapters provide a |
https://en.wikipedia.org/wiki/Norman%20Macleod%20Ferrers | Norman Macleod Ferrers (11 August 1829 – 31 January 1903) was a British mathematician and university administrator and editor of a mathematical journal.
Career and research
Ferrers was educated at Eton College before studying at Gonville and Caius College, Cambridge, where he was Senior Wrangler in 1851. He was appointed to a Fellowship at the college in 1852, was called to the bar in 1855 and was ordained deacon in 1859 and priest in 1860. In 1880, he was appointed Master of the college, and served as vice-chancellor of Cambridge University from 1884 to 1885.
Ferrers made many contributions to mathematical literature. From 1855 to 1891 he worked with J. J. Sylvester as editors, with others, in publishing The Quarterly Journal of Pure and Applied Mathematics. Ferrers assembled the papers of George Green for publication in 1871.
In 1861 he published "An Elementary Treatise on Trilinear Co-ordinates". One of his early contributions was on Sylvester's development of Poinsot's representation of the motion of a rigid body about a fixed point.
In 1871 he first suggested to extend the equations of motion with nonholonomic constraints.
His another treatise on "Spherical Harmonics," published in 1877, presented many original features.
In 1881 he studied Kelvin's investigation of the law of distribution of electricity in equilibrium on an uninfluenced spherical bowl
and made the addition of finding the potential at any point of space in zonal harmonics.
He died at the College Lodge on 31 January 1903.
Integer partitions
Ferrers is associated with a particular way of arranging the partition of a natural number p. If p is the sum of n terms, the largest of which is m, then the Ferrers diagram starts with a row of m dots. The terms are arranged in order, and a row of dots corresponds to each term.
Adams, Ferrers, and Sylvester articulated this theorem of partitions: "The number of modes of partitioning (n) into (m) parts is equal to the number of modes of partitioning |
https://en.wikipedia.org/wiki/Honeywell%20200 | The Honeywell 200 was a character-oriented two-address commercial computer introduced by Honeywell in December 1963, the basis of later models in Honeywell 200 Series, including 1200, 1250, 2200, 3200, 4200 and others, and the character processor of the Honeywell 8200 (1968).
Introduced to compete with IBM's 1401, the H200 was two or three times faster and, with software support, most of the time could execute IBM 1401 programs without need for their recompilation or reassembly. The Liberator marketing campaign exploited this compatibility, and was credited in later Honeywell publicity statements with stalling the sales of IBM 1401 machines. Honeywell claimed an initial rush of hundreds of orders for the H200 that itself stalled when IBM countered with a marketing emphasis on their System 360 product range that was then under development.
Architecture
As designed by Director of Engineering William L. Gordon, the H200 memory consisted of individually addressed characters, each composed of six data bits, two punctuation bits and a parity bit. The two punctuation bits recorded a word mark and an item mark, while both being set constituted a record mark. The item bit permitted item moves and record moves in addition to word moves (move successive characters one-by-one starting at the addresses given in the instruction, stopping when the relevant punctuation mark was found set in either field).
An instruction consisted of a one-character op-code, up to two operand addresses and an optional single character variant. Usually the op-code character would be word-marked, confirming the end of the previous instruction. An item-marked op-code would be handled differently from normal, and this was used in the emulation of IBM 1401 instructions that were not directly compatible. In two-character address mode, the full address defined one character in the 4K block currently addressed by the relevant register. In three-character address mode, the first three bits of an operan |
https://en.wikipedia.org/wiki/Patterson%20function | The Patterson function is used to solve the phase problem in X-ray crystallography. It was introduced in 1935 by Arthur Lindo Patterson while he was a visiting researcher in the laboratory of Bertram Eugene Warren at MIT.
The Patterson function is defined as
It is essentially the Fourier transform of the intensities rather than the structure factors. The Patterson function is also equivalent to the electron density convolved with its inverse:
Furthermore, a Patterson map of N points will have peaks, excluding the central (origin) peak and any overlap.
The peaks' positions in the Patterson function are the interatomic distance vectors and the peak heights are proportional to the product of the number of electrons in the atoms concerned.
Because for each vector between atoms i and j there is an oppositely oriented vector of the same length (between atoms j and i), the Patterson function always has centrosymmetry.
One-dimensional example
Consider the series of delta functions given by
The Patterson function is given by the following series of delta functions and unit step functions |
https://en.wikipedia.org/wiki/Design%20for%20testing | Design for testing or design for testability (DFT) consists of IC design techniques that add testability features to a hardware product design. The added features make it easier to develop and apply manufacturing tests to the designed hardware. The purpose of manufacturing tests is to validate that the product hardware contains no manufacturing defects that could adversely affect the product's correct functioning.
Tests are applied at several steps in the hardware manufacturing flow and, for certain products, may also be used for hardware maintenance in the customer's environment. The tests are generally driven by test programs that execute using automatic test equipment (ATE) or, in the case of system maintenance, inside the assembled system itself. In addition to finding and indicating the presence of defects (i.e., the test fails), tests may be able to log diagnostic information about the nature of the encountered test fails. The diagnostic information can be used to locate the source of the failure.
In other words, the response of vectors (patterns) from a good circuit is compared with the response of vectors (using the same patterns) from a DUT (device under test). If the response is the same or matches, the circuit is good. Otherwise, the circuit is not manufactured as it was intended.
DFT plays an important role in the development of test programs and as an interface for test application and diagnostics. Automatic test pattern generation, or ATPG, is much easier if appropriate DFT rules and suggestions have been implemented.
History
DFT techniques have been used at least since the early days of electric/electronic data processing equipment. Early examples from the 1940s/50s are the switches and instruments that allowed an engineer to "scan" (i.e., selectively probe) the voltage/current at some internal nodes in an analog computer [analog scan]. DFT often is associated with design modifications that provide improved access to internal circuit elemen |
https://en.wikipedia.org/wiki/Electrical%20ballast | An electrical ballast is a device placed in series with a load to limit the amount of current in an electrical circuit.
A familiar and widely used example is the inductive ballast used in fluorescent lamps to limit the current through the tube, which would otherwise rise to a destructive level due to the negative differential resistance of the tube's voltage-current characteristic.
Ballasts vary greatly in complexity. They may be as simple as a resistor, inductor, or capacitor (or a combination of these) wired in series with the lamp; or as complex as the electronic ballasts used in compact fluorescent lamps (CFLs).
Current limiting
An electrical ballast is a device that limits the current through an electrical load. These are most often used when a load (such as an arc discharge) has its terminal voltage decline when current through the load increases. If such a device were connected to a constant-voltage power supply, it would draw an increasing amount of current until it is destroyed or causes the power supply to fail. To prevent this, a ballast provides a positive resistance or reactance that limits the current. The ballast provides for the proper operation of the negative-resistance device by limiting current.
Ballasts can also be used simply to limit the current in an ordinary, positive-resistance circuit. Prior to the advent of solid-state ignition, automobile ignition systems commonly included a ballast resistor to regulate the voltage applied to the ignition system.
Resistors
Fixed resistors
For simple, low-powered loads such as a neon lamp, a fixed resistor is commonly used. Because the resistance of the ballast resistor is large it determines the current in the circuit, even in the face of negative resistance introduced by the neon lamp.
Ballast was also a component used in early model automobile engines that lowered the supply voltage to the ignition system after the engine had been started. Starting the engine requires a significant amount |
https://en.wikipedia.org/wiki/International%20Food%20Policy%20Research%20Institute | The International Food Policy Research Institute (IFPRI) is an international agricultural research center founded in 1975 to improve the understanding of national agricultural and food policies to promote the adoption of innovations in agricultural technology. Additionally, IFPRI was meant to shed more light on the role of agricultural and rural development in the broader development pathway of a country. The mission of IFPRI is to provide research-based policy solutions that sustainably reduce poverty and end hunger and malnutrition.
IFPRI carries out food policy research and disseminates it through hundreds of publications, bulletins, conferences, and other initiatives. IFPRI was organized as a District of Columbia non-profit, non-stock corporation on March 5, 1975, and its first research bulletin was produced in February 1976. IFPRI operates in more than 50 countries with offices in several developing countries, including China, Ethiopia, and India, and has research staff working in many more countries around the world. Most of the research takes place in developing countries in Central America, South America, Africa, and Asia.
IFPRI is part of a network of international research institutes funded in part by the CGIAR, which in turn is funded by governments, private businesses and foundations, and the World Bank.
Scope
IFPRI's institutional strategy rests on three pillars: research, capacity strengthening, and policy communication.
Research areas
Research topics have included low crop and animal productivity, and environmental degradation, water management, fragile lands, property rights, collective action, sustainable intensification of agricultural production, the impact of climate change on poor farmers, the problems and opportunities of biotechnology, food security, micronutrient malnutrition, microfinance programs, urban food security, resource allocation within households, and school feeding in low-income countries.
Gender and development
One major ar |
https://en.wikipedia.org/wiki/Enzyme%20assay | Enzyme assays are laboratory methods for measuring enzymatic activity. They are vital for the study of enzyme kinetics and enzyme inhibition.
Enzyme units
The quantity or concentration of an enzyme can be expressed in molar amounts, as with any other chemical, or in terms of activity in enzyme units.
Enzyme activity
Enzyme activity is a measure of the quantity of active enzyme present and is thus dependent on various physical conditions, which should be specified.
It is calculated using the following formula:
where
Enzyme activity
Moles of substrate converted per unit time
Rate of the reaction
Reaction volume
The SI unit is the katal, 1 katal = 1 mol s−1 (mole per second), but this is an excessively large unit. A more practical and commonly used value is enzyme unit (U) = 1 μmol min−1 (micromole per minute). 1 U corresponds to 16.67 nanokatals.
Enzyme activity as given in katal generally refers to that of the assumed natural target substrate of the enzyme. Enzyme activity can also be given as that of certain standardized substrates, such as gelatin, then measured in gelatin digesting units (GDU), or milk proteins, then measured in milk clotting units (MCU). The units GDU and MCU are based on how fast one gram of the enzyme will digest gelatin or milk proteins, respectively. 1 GDU approximately equals 1.5 MCU.
An increased amount of substrate will increase the rate of reaction with enzymes, however once past a certain point, the rate of reaction will level out because the amount of active sites available has stayed constant.
Specific activity
The specific activity of an enzyme is another common unit. This is the activity of an enzyme per milligram of total protein (expressed in μmol min−1 mg−1). Specific activity gives a measurement of enzyme purity in the mixture. It is the micro moles of product formed by an enzyme in a given amount of time (minutes) under given conditions per milligram of total proteins. Specific activity is equal to the rate of reacti |
https://en.wikipedia.org/wiki/Gaussian%20optics | Gaussian optics is a technique in geometrical optics that describes the behaviour of light rays in optical systems by using the paraxial approximation, in which only rays which make small angles with the optical axis of the system are considered. In this approximation, trigonometric functions can be expressed as linear functions of the angles. Gaussian optics applies to systems in which all the optical surfaces are either flat or are portions of a sphere. In this case, simple explicit formulae can be given for parameters of an imaging system such as focal length, magnification and brightness, in terms of the geometrical shapes and material properties of the constituent elements.
Gaussian optics is named after mathematician and physicist Carl Friedrich Gauss, who showed that an optical system can be characterized by a series of cardinal points, which allow one to calculate its optical properties. |
https://en.wikipedia.org/wiki/Perfect%20conductor | A perfect conductor or perfect electric conductor (PEC) is an idealized material exhibiting infinite electrical conductivity or, equivalently, zero resistivity (cf. perfect dielectric). While perfect electrical conductors do not exist in nature, the concept is a useful model when electrical resistance is negligible compared to other effects. One example is ideal magnetohydrodynamics, the study of perfectly conductive fluids. Another example is electrical circuit diagrams, which carry the implicit assumption that the wires connecting the components have no resistance. Yet another example is in computational electromagnetics, where PEC can be simulated faster, since the parts of equations that take finite conductivity into account can be neglected.
Properties of perfect conductors
Perfect conductors:
have exactly zero electrical resistance - a steady current within a perfect conductor will flow without losing energy to resistance. Resistance is what causes heating in conductors, thus a perfect conductor will generate no heat. Since energy is not being lost to heat, the current will not dissipate; it will flow indefinitely within the perfect conductor until there exists no potential difference.
require a constant magnetic flux - the magnetic flux within the perfect conductor must be constant with time. Any external field applied to a perfect conductor will have no effect on its internal field configuration.
Distinction between a perfect conductor and a superconductor
Superconductors, in addition to having no electrical resistance, exhibit quantum effects such as the Meissner effect and quantization of magnetic flux.
In perfect conductors, the interior magnetic field must remain fixed but can have a zero or nonzero value. In real superconductors, all magnetic flux is expelled during the phase transition to superconductivity (the Meissner effect), and the magnetic field is always zero within the bulk of the superconductor.
Mesoscopic scale
Non-super-conducting metal |
https://en.wikipedia.org/wiki/Index%20of%20mechanical%20engineering%20articles | This is an alphabetical list of articles pertaining specifically to mechanical engineering. For a broad overview of engineering, please see List of engineering topics. For biographies please see List of engineers.
A
Acceleration –
Accuracy and precision –
Actual mechanical advantage –
Aerodynamics –
Agitator (device) –
Air handler –
Air conditioner –
Air preheater –
Allowance –
American Machinists' Handbook –
American Society of Mechanical Engineers –
Ampere –
Applied mechanics –
Antifriction –
Archimedes' screw –
Artificial intelligence –
Automaton clock –
Automobile –
Automotive engineering –
Axle –
Air Compressor
B
Backlash –
Balancing –
Beale Number –
Bearing –
Belt (mechanical) –
Bending –
Biomechatronics –
Bogie –
Brittle –
Buckling –
Bus--
Bushing –
Boilers & boiler systems
BIW--
C
CAD –
CAM –
CAID –
Calculator –
Calculus –
Car handling –
Carbon fiber –
Classical mechanics –
Clean room design –
Clock –
Clutch –
CNC –
Coefficient of thermal expansion –
Coil spring –
Combustion –
Composite material –
Compression ratio –
Compressive strength –
Computational fluid dynamics –
Computer –
Computer-aided design –
Computer-aided industrial design –
Computer-numerically controlled –
Conservation of mass –
Constant-velocity joint –
Constraint –
Continuum mechanics –
Control theory –
Corrosion –
Cotter pin –
Crankshaft –
Cybernetics –
D
Damping ratio –
Deformation (engineering) –
Delamination –
Design –
Diesel Engine –
Differential –
Dimensionless number –
Diode –
Diode laser –
Drafting –
Drifting –
Driveshaft –
Dynamics –
Design for Manufacturability for CNC machining –
E
Elasticity –
Elasticity tensor -
Electric motor –
Electrical engineering –
Electrical circuit –
Electrical network –
Electromagnetism –
Electronic circuit –
Electronics –
Energy –
Engine –
Engineering –
Engineering cybernetics –
Engineering drawing –
Engineering economics –
Engineering ethics –
Engineering management –
Engineering society –
Exploratory engineering –
F
( Fits and tolerances)---
Fa |
https://en.wikipedia.org/wiki/Creeping%20wave | According to the principle of diffraction, when a wave front passes an obstruction, it spreads out into the shadowed space. A creeping wave in electromagnetism or acoustics is the wave that is diffracted around the shadowed surface of a smooth body such as a sphere.
Creeping waves greatly extend the ground wave propagation of long wavelength (low frequency) radio. They also cause both of a person's ears to hear a sound, rather than only the ear on the side of the head facing the origin of the sound. In radar ranging, the creeping wave return appears to come from behind the target.
Vladimir Fock made important contributions to the understanding and calculation of creeping waves. They are described by Airy functions.
Electromagnetic radiation
Acoustics
Radio |
https://en.wikipedia.org/wiki/Current%20sheet | A current sheet is an electric current that is confined to a surface, rather than being spread through a volume of space. Current sheets feature in magnetohydrodynamics (MHD), the study of the behavior of electrically conductive fluids: if there is an electric current through part of the volume of such a fluid, magnetic forces tend to expel it from the fluid, compressing the current into thin layers that pass through the volume.
The largest occurring current sheet in the Solar System is the so-called Heliospheric current sheet, which is about 10,000 km thick, and extends from the Sun and out beyond the orbit of Pluto.
In astrophysical plasmas such as the solar corona, current sheets theoretically might have an aspect ratio (breadth divided by thickness) as high as 100,000:1. By contrast, the pages of most books have an aspect ratio close to 2000:1. Because current sheets are so thin in comparison to their size, they are often treated as if they have zero thickness; this is a result of the simplifying assumptions of ideal MHD. In reality, no current sheet may be infinitely thin because that would require infinitely fast motion of the charge carriers whose motion causes the current.
Current sheets in plasmas store energy by increasing the energy density of the magnetic field. Many plasma instabilities arise near strong current sheets, which are prone to collapse, causing magnetic reconnection and rapidly releasing the stored energy. This process is the cause of solar flares and is one reason for the difficulty of magnetic confinement fusion, which requires strong electric currents in a hot plasma.
Magnetic field of an infinite current sheet
An infinite current sheet can be modelled as an infinite number of parallel wires all carrying the same current. Assuming each wire carries current I, and there are N wires per unit length, the magnetic field can be derived using Ampère's law:
R is a rectangular loop surrounding the current sheet, perpendicular to the p |
https://en.wikipedia.org/wiki/Higher-order%20abstract%20syntax | In computer science, higher-order abstract syntax (abbreviated HOAS) is a technique for the representation of abstract syntax trees for languages with variable binders.
Relation to first-order abstract syntax
An abstract syntax is abstract because it is represented by mathematical objects that have certain structure by their very nature. For instance, in first-order abstract syntax (FOAS) trees, as commonly used in compilers, the tree structure implies the subexpression relation, meaning that no parentheses are required to disambiguate programs (as they are, in the concrete syntax). HOAS exposes additional structure: the relationship between variables and their binding sites. In FOAS representations, a variable is typically represented with an identifier, with the relation between binding site and use being indicated by using the same identifier. With HOAS, there is no name for the variable; each use of the variable refers directly to the binding site.
There are a number of reasons why this technique is useful. First, it makes the binding structure of a program explicit: just as there is no need to explain operator precedence in a FOAS representation, there is no need to have the rules of binding and scope at hand to interpret a HOAS representation. Second, programs that are
alpha-equivalent (differing only in the names of bound variables) have identical representations in HOAS, which can make equivalence checking more efficient.
Implementation
One mathematical object that could be used to implement HOAS is a graph where variables are associated with their binding sites via edges. Another popular way to implement HOAS (in, for example, compilers) is with de Bruijn indices.
Use in logic programming
The first programming language which directly supported
λ-bindings in syntax was the higher-order logic programming
language λProlog.
The paper that introduced the term HOAS
used
λProlog code to illustrate it. Unfortunately, when one transfers the
term HOAS from t |
https://en.wikipedia.org/wiki/Pelagic%20fish | Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that live on or near the bottom, and reef fish that are associated with coral reefs.
The marine pelagic environment is the largest aquatic habitat on Earth, occupying 1,370 million cubic kilometres (330 million cubic miles), and is the habitat for 11% of known fish species. The oceans have a mean depth of . About 98% of the total water volume is below , and 75% is below .
Marine pelagic fish can be divided into coastal (inshore) fish and oceanic (offshore) fish. Coastal pelagic fish inhabit the relatively shallow and sunlit waters above the continental shelf, while oceanic pelagic fish inhabit the vast and deep waters beyond the continental shelf (even though they also may swim inshore).
Pelagic fish range in size from small coastal forage fish, such as herrings and sardines, to large apex predator oceanic fishes, such as bluefin tuna and oceanic sharks. They are usually agile swimmers with streamlined bodies, capable of sustained cruising on long-distance migrations. Many pelagic fish swim in schools weighing hundreds of tonnes. Others, such as the large ocean sunfish, are solitary. There are also freshwater pelagic fish in some of the larger lakes, such as the Lake Tanganyika sardine.
Epipelagic fish
Epipelagic fish inhabit the epipelagic zone, the uppermost layer of the water column, ranging from sea level down to . It is also referred to as the surface waters or the sunlit zone, and includes the photic zone. The photic zone is defined as the surface waters down to the depth where the sunlight is attenuated to 1% of the surface value. This depth depends on how turbid the water is, but can extend to in clear water, coinciding with the epipelagic zone. The photic zone allows sufficient light for phytoplankton to photosynthesize.
A vast habitat for most pelagic fish, the epipelagic zone is well lit so visual predato |
https://en.wikipedia.org/wiki/K%C4%ABpuka | A kīpuka is an area of land surrounded by one or more younger lava flows. A kīpuka forms when lava flows on either side of a hill, ridge, or older lava dome as it moves downslope or spreads from its source. Older and more weathered than their surroundings, kīpukas often appear to be like islands within a sea of lava flows. They are often covered with soil and late ecological successional vegetation that provide visual contrast as well as habitat for animals in an otherwise inhospitable environment. In volcanic landscapes, kīpukas play an important role as biological reservoirs or refugia for plants and animals, from which the covered land can be recolonized.
Etymology
Kīpuka, along with aā and pāhoehoe, are Hawaiian words related to volcanology that have entered the lexicon of geology. Descriptive proverbs and poetical sayings in Hawaiian oral tradition also use the word, in an allusive sense, to mean a place where life or culture endures, regardless of any encroachment or interference. By extension, from the appearance of island "patches" within a highly contrasted background, any similarly noticeable variation or change of form, such as an opening in a forest, or a clear place in a congested setting, may be colloquially called kīpuka.
Significance to research
Kīpuka provides useful study sites for ecological research because they facilitate replication; multiple kīpuka in a system (isolated by the same lava flow) will tend to have uniform substrate age and successional characteristics, but are often isolated-enough from their neighbors to provide meaningful, comparable differences in size, invasion, etc. They are also receptive to experimental treatments. Kīpuka along Saddle Road on Hawaii have served as the natural laboratory for a variety of studies, examining ecological principles like island biogeography, food web control, and biotic resistance to invasiveness. In addition, Drosophila silvestris populations inhabit kīpukas, making kīpukas useful for unders |
https://en.wikipedia.org/wiki/Fluxon | In physics, a fluxon is a quantum of electromagnetic flux. The term may have any of several related meanings.
Superconductivity
In the context of superconductivity, in type II superconductors fluxons (also known as Abrikosov vortices) can form when the applied field lies between and . The fluxon is a small whisker of normal phase surrounded by superconducting phase, and Supercurrents circulate around the normal core. The magnetic field through such a whisker and its neighborhood, which has size of the order of London penetration depth (~100 nm), is quantized because of the phase properties of the magnetic vector potential in quantum electrodynamics, see magnetic flux quantum for details.
In the context of long Superconductor-Insulator-Superconductor Josephson tunnel junctions, a fluxon (aka Josephson vortex) is made of circulating supercurrents and has no normal core in the tunneling barrier. Supercurrents circulate just around the mathematical center of a fluxon, which is situated with the (insulating) Josephson barrier. Again, the magnetic flux created by circulating supercurrents is equal to a magnetic flux quantum (or less, if the superconducting electrodes of the Josephson junction are thinner than ).
Magnetohydrodynamics modeling
In the context of numerical MHD modeling, a fluxon is a discretized magnetic field line, representing a finite amount of magnetic flux in a localized bundle in the model. Fluxon models are explicitly designed to preserve the topology of the magnetic field, overcoming numerical resistivity effects in Eulerian models. |
https://en.wikipedia.org/wiki/Billhook | A billhook or bill hook, also called a pruning knife or spar hook, is a versatile cutting tool used widely in agriculture and forestry for cutting woody material such as shrubs, small trees and branches. It is distinct from the sickle. It was commonly used in Europe with an important variety of traditional local patterns. Elsewhere, it was also developed locally such as in the Indian subcontinent, or introduced regionally as in the Americas, South Africa, and Oceania by European settlers.
Design
The blade is usually made from a medium-carbon steel in varying weights and lengths, but typically long. Blades are straight near the handle but have an increasingly strong curve towards the end. The blade is generally sharpened only on the inside of the curve, but double-edged billhooks, or "broom hooks", also have a straight secondary edge on the back.
The blade is fixed to a wooden handle, in Europe usually made from ash due to its strength and ability to deal with repeated impact. Handles are mostly long and may be "caulked" or round. ("Caulked" handles have a knob sticking out on one side at the bottom of the handle, intended to help to help keep the tool from slipping out of your hand. See sidebar.) Longer handles are sometimes used for heavier patterns, making the tool double-handed. The blade and handle are usually linked by a tang passing through the handle, but sometimes a socket that encloses the blade. Some styles of billhook have scales of hardwood or horn fitted to the handle.
Some billhooks (for example the Kent pattern) have a single-bevelled blade, available in both right- and left-handed versions, others (such as the Machynlleth pattern) have dished blades (concave one side and convex the other), or a pronounced thickened nose (such as the Monmouth pattern). The reasons for many of these variations are now lost.
The use of a billhook is between that of a knife and an axe. It is often used for cutting woody plants such as saplings and small branch |
https://en.wikipedia.org/wiki/Macrometer | A macrometer is an instrument for measuring the size and distance of distant objects. Distant in this sense means a length that can not be readily measured by a calibrated length. The optical version of this instrument used two mirrors on a common sextant. By aligning the object on the mirrors using a precise vernier, the position of the mirrors could be used to compute the range to the object. The distance and the angular size of the object would then yield the actual size.
See also
Rangefinder
Theodolite |
https://en.wikipedia.org/wiki/Password%20psychology | Living in the intersection of cryptography and psychology, password psychology is the study of what makes passwords or cryptographic keys easy to remember or guess.
In order for a password to work successfully and provide security to its user, it must be kept secret and un-guessable; this also requires the user to memorize their password. The psychology behind choosing a password is a unique balance between memorization, security and convenience. Password security involves many psychological and social issues including; whether or not to share a password, the feeling of security, and the eventual choice of whether or not to change a password. Passwords may also be reflective of personality. Those who are more uptight or security-oriented may choose longer or more complicated passwords. Those who are lax or who feel more secure in their everyday lives may never change their password. The most common password is Password1, which may point to convenience over security as the main concern for internet users.
History
The use and memorization of both nonsense and meaningful alphanumeric material has had a long history in psychology beginning with Hermann Ebbinghaus. Since then, numerous studies have established that not only are both meaningful and nonsense “words” easily forgotten, but that both their forgetting curves are exponential with time. Chomsky advocates meaning as arising from semantic features, leading to the idea of “concept formation” in the 1930s.
Current research
Research is being done to find new ways of enhancing and creating new techniques for cognitive ability and memorization when it comes to password selection. A study from 2004 indicates that the typical college student creates about 4 different passwords for use with about 8 different items, such as computers, cell phones, and email accounts, and the typical password is used for about two items. Information about the type of passwords points to an approximate even split between linguistic and nu |
https://en.wikipedia.org/wiki/Brute%20Force%3A%20Cracking%20the%20Data%20Encryption%20Standard | Brute Force: Cracking the Data Encryption Standard (2005, Copernicus Books ) is a book by Matt Curtin about cryptography.
In this book, the author accounts his involvement in the DESCHALL Project, mobilizing thousands of personal computers in 1997 in order to meet the challenge to crack a single message encrypted with DES.
This was and remains one of the largest collaborations of any kind on a single project in history.
The message was unencrypted on June 18 and was found to be "Strong cryptography makes the world a safer place."
This is also the message of Curtin's book where he uses a personal account to reveal to the uninitiated reader some insight into a topic of growing importance which is both technically and politically complicated.
External links
Archive of project material
Archive of DESCHALL home page
2005 non-fiction books
Cryptography books |
https://en.wikipedia.org/wiki/MetaWeblog | The MetaWeblog API is an application programming interface created by software developer Dave Winer that enables weblog entries to be written, edited, and deleted using web services.
The API is implemented as an XML-RPC web service with three methods whose names describe their function: metaweblog.newPost(), metaweblog.getPost() and metaweblog.editPost(). These methods take arguments that specify the blog author's username and password along with information related to an individual weblog entry.
The impetus for the creation of the API in 2002 was perceived limitations of the Blogger API, which serves the same purpose. Another weblog publishing API, the Atom Publishing Protocol became an IETF Internet standard (RFC 5023) in October 2007. Subsequently, another weblog publishing API, Micropub, which was developed with modern technologies like OAuth, became a W3C Recommendation in May 2017.
Many blog software applications and content management systems support the MetaWeblog API, as do numerous desktop clients.
See also
Atom Publishing Protocol
Micropub
XML-based standards
Web services
Inter-process communication
Internet protocols |
https://en.wikipedia.org/wiki/Stigma%20%28botany%29 | The stigma (: stigmas or stigmata) is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower.
Description
The stigma, together with the style and ovary (typically called the stigma-style-ovary system) comprises the pistil, which is part of the gynoecium or female reproductive organ of a plant. The stigma itself forms the distal portion of the style, or stylodia, and is composed of , the cells of which are receptive to pollen. These may be restricted to the apex of the style or, especially in wind pollinated species, cover a wide surface.
The stigma receives pollen and it is on the stigma that the pollen grain germinates. Often sticky, the stigma is adapted in various ways to catch and trap pollen with various hairs, flaps, or sculpturings. The pollen may be captured from the air (wind-borne pollen, anemophily), from visiting insects or other animals (biotic pollination), or in rare cases from surrounding water (hydrophily). Stigma can vary from long and slender to globe shaped to feathery.
Pollen is typically highly desiccated when it leaves an anther. Stigma have been shown to assist in the rehydration of pollen and in promoting germination of the pollen tube. Stigma also ensure proper adhesion of the correct species of pollen. Stigma can play an active role in pollen discrimination and some self-incompatibility reactions, that reject pollen from the same or genetically similar plants, involve interaction between the stigma and the surface of the pollen grain.
Shape
The stigma is often split into lobes, e.g. trifid (three lobed), and may resemble the head of a pin (capitate), or come to a point (punctiform). The shape of the stigma may vary considerably:
Style
Structure
The style is a narrow upward extension of the ovary, connecting it to the stigmatic papillae. Occasionally it may be absent, in which case the stigma is described as sessile. Styles are generally tube-like—either long or short. The style can be open (cont |
https://en.wikipedia.org/wiki/Wolf%20effect | The Wolf effect (sometimes Wolf shift) is a frequency shift in the electromagnetic spectrum.
The phenomenon occurs in several closely related phenomena in radiation physics, with analogous effects occurring in the scattering of light. It was first predicted by Emil Wolf in 1987 and subsequently confirmed in the laboratory in acoustic sources by Mark F. Bocko, David H. Douglass, and Robert S. Knox, and a year later in optic sources by Dean Faklis and George Morris in 1988.
Theoretical description
In optics, two non-Lambertian sources that emit beamed energy can interact in a way that causes a shift in the spectral lines. It is analogous to a pair of tuning forks with similar frequencies (pitches), connected together mechanically with a sounding board; there is a strong coupling that results in the resonant frequencies getting "dragged down" in pitch. The Wolf Effect requires that the waves from the sources are partially coherent - the wavefronts being partially in phase. Laser light is coherent while candlelight is incoherent, each photon having random phase. It can produce either redshifts or blueshifts, depending on the observer's point of view, but is redshifted when the observer is head-on.
For two sources interacting while separated by a vacuum, the Wolf effect cannot produce shifts greater than the linewidth of the source spectral line, since it is a position-dependent change in the distribution of the source spectrum, not a method by which new frequencies may be generated. However, when interacting with a medium, in combination with effects such as Brillouin scattering it may produce distorted shifts greater than the linewidth of the source.
Notes
Scattering
Spectroscopy |
https://en.wikipedia.org/wiki/People%20Finder%20Interchange%20Format | People Finder Interchange Format (PFIF) is a widely used open data standard for information about missing or displaced people. PFIF was designed to enable information sharing among governments, relief organizations, and other survivor registries to help people find and contact their family and friends after a disaster.
Overview
PFIF is extended from XML. It consists of person records, which contain identifying information about a person, and note records, which contain comments and updates on the status and location of a person. Each note is attached to one person. PFIF defines the set of fields in these records and an XML-based format to store or transfer them. PFIF XML records can be embedded in Atom feeds or RSS feeds.
PFIF allows different repositories of missing person data to exchange and aggregate their records. Every record has a unique identifier, which indicates the domain name of the original repository where the record was created. The unique record identifier is preserved as the record is copied from one repository to another. For example, any repository that receives a copy of a given person can publish a note attached to that person, and even as the note and person are copied to other repositories, they remain traceable to their respective original sources.
History
Within three days after the 2001 September 11 attacks, people were using over 25 different online forums and survivor registries to report and check on their family and friends.
One of the first and largest of these was the survivor registry at safe.millennium.berkeley.edu, which was created by graduate students Ka-Ping Yee and Miriam Walker and hosted on the Millennium computer cluster at UC Berkeley. To reduce the confusion caused by the proliferation of different websites, the Berkeley survivor registry began collecting data from several of the other major sites into one searchable database. Because the information was formatted differently from site to site, each site required manu |
https://en.wikipedia.org/wiki/Tokyo%20Skytree | , is a broadcasting and observation tower in Sumida, Tokyo. It became the tallest structure in Japan in 2010 and reached its full height of in March 2011, making it the tallest tower in the world, displacing the Canton Tower, and the third tallest structure in the world after the Merdeka 118 () and the Burj Khalifa (829.8 m or 2,722 ft). It is also the tallest freestanding structure in the OECD, the G20 and G7 countries.
The tower is the primary television and radio broadcast site for the Kantō region; the older Tokyo Tower no longer gives complete digital terrestrial television broadcasting coverage because it is surrounded by high-rise buildings. Skytree was completed on Leap Day, 29 February 2012, with the tower opening to the public on 22 May 2012. The tower is the centrepiece of a large commercial development funded by Tobu Railway (which owns the complex) and a group of six terrestrial broadcasters headed by NHK. Trains stop at the adjacent Tokyo Skytree Station and nearby Oshiage Station. The complex is northeast of Tokyo Station. In addition, there is the Sumida Aquarium in the "Tokyo Solamachi" complex.
Design
The tower's design was published on 24 November 2006, based on the following three concepts:
Fusion of neofuturistic design and the traditional beauty of Japan
Catalyst for revitalization of the city
Contribution to disaster prevention – "Safety and Security"
The base of the tower has a structure similar to a tripod; from a height of about and above, the tower's structure is cylindrical to offer panoramic views of the river and the city. There are observatories at , with a capacity of up to 2,000 people, and , with a capacity of 900 people. The upper observatory features a spiral, glass-covered skywalk in which visitors ascend the last 5 metres to the highest point at the upper platform. A section of glass flooring gives visitors a direct downward view of the streets below.
Earthquake resistance
The tower has seismic proofing, including a ce |
https://en.wikipedia.org/wiki/KHRR | KHRR (channel 40) is a television station in Tucson, Arizona, United States, serving as the market's outlet for the Spanish-language network Telemundo. Owned and operated by NBCUniversal's Telemundo Station Group, the station maintains studios on North Stone Avenue in downtown Tucson, and its transmitter is located atop the Tucson Mountains.
Although identifying as a separate station in its own right, KHRR is considered a semi-satellite of KTAZ (channel 39) in Phoenix. As such, it simulcasts all Telemundo programming as provided through its parent, but airs separate commercial inserts and legal identifications, and has its own website. Local newscasts, produced by KTAZ and branded as Noticiero Telemundo Arizona, are simulcast on both stations. Although KHRR maintains its own facilities, master control and most internal operations are based at KTAZ's studios on South 33rd Place in Phoenix.
History
KPOL
On November 28, 1983, a construction permit was granted to JP Communications, owned by Julius Polan of Chicago, for a new commercial television station on channel 40 in Tucson. Channel 40 had been occupied since November 1980 by a translator of Phoenix Spanish-language station KTVW. JP beat out Valle Verde Broadcasting Corporation, which proposed a full-service Spanish-language outlet, and five other applicants, including Focus Broadcasting and National Group Telecommunications. The permit was approved after JP paid out a cash settlement to rival Sunwest Communications.
Taking the call letters KPOL, construction began in 1984, forcing the KTVW translator to move to channel 52. The station also secured a package of Phoenix Suns road games. However, channel 40 missed its planned November start because its studios had not been completed. Meanwhile, minority investor David Jácome sued, saying that Polan had brought him in to add a minority owner to the ownership group but that he had been squeezed out.
KPOL signed on January 5, 1985. It was the second new independent |
https://en.wikipedia.org/wiki/Appressorium | An appressorium is a specialized cell typical of many fungal plant pathogens that is used to infect host plants. It is a flattened, hyphal "pressing" organ, from which a minute infection peg grows and enters the host, using turgor pressure capable of punching through even Mylar.
Following spore attachment and germination on the host surface, the emerging germ tube perceives physical cues such as surface hardness and hydrophobicity, as well as chemical signals including wax monomers that trigger appressorium formation. Appressorium formation begins when the tip of the germ tube ceases polar growth, hooks, and begins to swell. The contents of the spore are then mobilized into the developing appressorium, a septum develops at the neck of the appressorium, and the germ tube and spore collapse and die. As the appressorium matures, it becomes firmly attached to the plant surface and a dense layer of melanin is laid down in the appressorium wall, except across a pore at the plant interface. Turgor pressure increases inside the appressorium and a penetration hypha emerges at the pore, which is driven through the plant cuticle into the underlying epidermal cells. The osmotic pressure exerted by the appressorium can reach up to 8 MPa, which allows it to puncture the plant cuticle. This pressure is achievable due to a melanin-pigmented cell wall which is impermeable to compounds larger than water molecules, so the highly-concentrated ions cannot escape from it.
Formation
The attachment of a fungal spore on the surface of the host plant is the first critical step of infection. Once the spore is hydrated, an adhesive mucilage is released from its tip. During germination, mucilaginous substances continue to be extruded at the tips of the germ tube, which are essential for germ tube attachment and appressorium formation. Spore adhesion and appressorium formation is inhibited by hydrolytic enzymes such as α-mannosidase, α-glucosidase, and protease, suggesting that the adhesive ma |
https://en.wikipedia.org/wiki/Ketura%2C%20Israel | Ketura () is a kibbutz in southern Israel. Located north of Eilat in the Aravah Valley, it falls under the jurisdiction of Hevel Eilot Regional Council. In it had a population of .
Name
The name Ketura was taken from a nearby hill and wadi, and is also the name of the second wife of Abraham ().
History
Ketura was founded in November 1973 by a group of young American Jewish immigrants, most of them members of the Zionist youth movement Young Judaea. Difficulties in the early years frustrated many of the inhabitants of the kibbutz, which caused many of the founders to leave. At the same time, more Young Judaeans joined the community, along with a variety of other immigrants as well as Israel Boy and Girl Scouts Federation graduates. Ketura is in the Southern Arava - Hevel Eilot Regional Council.
Today Ketura has about 165 members and several young families who are candidates to become members. During the year there are about 500 people living on Ketura, members and their families, students in the Arava Institute for Environmental Studies, volunteers from around the world, Arava International Center for Agriculture Training (AICAT) students from around the world, NOAM youth movement members in various programs such as gap year or service year (shnat sherut), Israeli post-army 'avoda muedefet' participants, and researchers who come to work in regional institutes.
Religious culture
Ketura is unique among kibbutzim for its religious pluralism. Although the kibbutz is not considered a religious kibbutz, Jewish dietary laws (kashrut) and Sabbath rules are observed in the dining room, public areas, and at social and cultural events, and there is a functioning congregation-led egalitarian synagogue. The population of the kibbutz is composed of observant, masorati (moderately observant), and secular members, an unusual situation for a kibbutz. Ketura received the Speaker of the Knesset Prize for religious tolerance as a result of its religious progressiveness.
Economy
|
https://en.wikipedia.org/wiki/Blue%20ice%20%28aviation%29 | In aviation, blue ice is frozen sewage material that has leaked mid-flight from commercial aircraft lavatory waste systems. It is a mixture of human biowaste and liquid disinfectant that freezes at high altitude. The name comes from the blue color of the disinfectant. Airlines are not allowed to dump their waste tanks mid-flight, and pilots have no mechanism by which to do so; however, leaks sometimes do occur from a plane's septic tank.
Danger of ground impact
There were at least 27 documented incidents of blue ice impacts in the United States between 1979 and 2003. These incidents typically happen under airport landing paths as the mass warms sufficiently to detach from the plane during its descent. A rare incident of falling blue ice causing damage to the roof of a home was reported on October 20, 2006 in Chino, California. A similar incident was reported in Leicester, UK, in 2007.
In 1971, a chunk of ice from an aircraft tore a large hole in the roof of the Essex Street Chapel in Kensington, London, and was one trigger for the demolition of the building.
In November 2011, a chunk of ice, the size of an orange, broke through the roof of a private house in Ratingen-Hösel, Germany.
In February 2013, a "football sized" ball of blue ice smashed through a conservatory roof in Clanfield, Hampshire, causing around £10,000 worth of damage.
In October 2016, a chunk of ice tore a hole in a private house in Amstelveen, The Netherlands.
In two incidents in May 2018, chunks of blue ice fell onto residents in Kelowna, British Columbia.
In November 2018, a chunk of ice fell from the sky and crashed through the roof of a home in Bristol, England.
Danger to aircraft
Blue ice can also be dangerous to the aircraft the National Transportation Safety Board has recorded three very similar incidents where waste from lavatories caused damage to the leaking aircraft, all involving Boeing 727s. In all three cases, waste from a leaking lavatory hit one (or the other) of the three |
https://en.wikipedia.org/wiki/Shelter%20from%20the%20Storm%3A%20A%20Concert%20for%20the%20Gulf%20Coast | Shelter from the Storm: A Concert for the Gulf Coast was a one-hour, commercial-free benefit concert television special that aired simulcast worldwide on September 9, 2005, at 8 p.m. ET/CT live (with a 30-second tape delay) from New York City and Los Angeles and tape delayed in the Mountain Time Zone and Pacific Time Zones. The special raised money for the relief efforts from the aftermath of Hurricane Katrina. It was broadcast in over 100 different countries. All proceeds went to the American Red Cross and The Salvation Army.
Production
The concert was a cooperative and collaborative global effort between ABC, CBS, NBC, FOX, UPN, and The WB. Several cable stations have also cleared space for the concert. It featured appearances and musical performances by celebrities from the world of film, television and music. Approximately $30 million was raised for the American Red Cross and The Salvation Army.
The event was produced by Joel Gallen and followed closely in the footprints of the 9/11 benefit concert, America: A Tribute to Heroes, which Gallen also produced. It featured performances by popular musicians along with commentary by various actors and other celebrities. Celebrities also answered phone calls to help collect donations.
Musical guests and performances
Randy Newman, "Louisiana 1927"
U2 with Mary J. Blige, "One" (recorded earlier that day in Toronto)
Alicia Keys with Alvin Slaughter, Shirley Caesar and Bishop Eric McDaniel: Gospel Medley: "Remember Me", Come by Here, My Lord" and "We Need To Hear From You"
Neil Young, "When God Made Me"
Foo Fighters, "Born on the Bayou"
Mariah Carey, "Fly Like a Bird"
Paul Simon, "Take Me to the Mardi Gras"
unknown New Orleans jazz band, coda
Dixie Chicks with Mike Campbell and Robert Randolph, "I Hope"
Kelly Clarkson, "Shelter"
Sheryl Crow, "The Water Is Wide"
Rod Stewart with Jerry Lawson & Talk of the Town, "People Get Ready"
Kanye West, "Jesus Walks"
Garth Brooks with Trisha Yearwood and Paul Shaffer, "Who'll Stop |
https://en.wikipedia.org/wiki/Affective%20neuroscience | Affective neuroscience is the study of how the brain processes emotions. This field combines neuroscience with the psychological study of personality, emotion, and mood. The basis of emotions and what emotions are remains an issue of debate within the field of affective neuroscience.
The term "affective neuroscience" was coined by neuroscientist Jaak Panksepp, at a time when cognitive neuroscience focused on parts of psychology that did not include emotion, such as attention or memory.
Affective neuroscience
Emotions are thought to be related to activity in brain areas that direct our attention, motivate our behavior, and help us make decisions about our environment. Early stages of research on emotions and the brain was conducted by Paul Broca, James Papez, and Paul D. MacLean. Their work suggests that emotion is related to a group of structures in the center of the brain called the limbic system. The limbic system is made up of the following brain structures:
Limbic system
Amygdala – The amygdala is made up of two small, round structures located closer to the forehead (anterior) to the hippocampi near the temporal poles. The amygdalae are involved in detecting and learning which parts of our surroundings are important and have emotional significance. They are critical for the production of emotion. They are known to be very important for negative emotions, especially fear. Amygdala activation often happens when we see a potential threat. The amygdala uses our past, related memories to help us make decisions about what is currently happening.
Thalamus – The thalamus is involved in combining sensory and motor signals and then sending that information to the cerebral cortex. The thalamus plays an important role in regulating sleep and wakefulness.
Hypothalamus – The hypothalamus is involved in producing a physical response (for example, crying) with an emotion. The hypothalamus is also used in reward circuits which are associated with positive emotions.
Hip |
https://en.wikipedia.org/wiki/Hermitian%20manifold | In mathematics, and more specifically in differential geometry, a Hermitian manifold is the complex analogue of a Riemannian manifold. More precisely, a Hermitian manifold is a complex manifold with a smoothly varying Hermitian inner product on each (holomorphic) tangent space. One can also define a Hermitian manifold as a real manifold with a Riemannian metric that preserves a complex structure.
A complex structure is essentially an almost complex structure with an integrability condition, and this condition yields a unitary structure (U(n) structure) on the manifold. By dropping this condition, we get an almost Hermitian manifold.
On any almost Hermitian manifold, we can introduce a fundamental 2-form (or cosymplectic structure) that depends only on the chosen metric and the almost complex structure. This form is always non-degenerate. With the extra integrability condition that it is closed (i.e., it is a symplectic form), we get an almost Kähler structure. If both the almost complex structure and the fundamental form are integrable, then we have a Kähler structure.
Formal definition
A Hermitian metric on a complex vector bundle E over a smooth manifold M is a smoothly varying positive-definite Hermitian form on each fiber. Such a metric can be viewed as a smooth global section h of the vector bundle such that for every point p in M,
for all , in the fiber Ep and
for all nonzero in Ep.
A Hermitian manifold is a complex manifold with a Hermitian metric on its holomorphic tangent bundle. Likewise, an almost Hermitian manifold is an almost complex manifold with a Hermitian metric on its holomorphic tangent bundle.
On a Hermitian manifold the metric can be written in local holomorphic coordinates (zα) as
where are the components of a positive-definite Hermitian matrix.
Riemannian metric and associated form
A Hermitian metric h on an (almost) complex manifold M defines a Riemannian metric g on the underlying smooth manifold. The metric g is defined to |
https://en.wikipedia.org/wiki/Circular%20dependency | In software engineering, a circular dependency is a relation between two or more modules which either directly or indirectly depend on each other to function properly. Such modules are also known as mutually recursive.
Overview
Circular dependencies are natural in many domain models where certain objects of the same domain depend on each other. However, in software design, circular dependencies between larger software modules are considered an anti-pattern because of their negative effects. Despite this, such circular (or cyclic) dependencies have been found to be widespread among the source files of real-world software. Mutually recursive modules are, however, somewhat common in functional programming, where inductive and recursive definitions are often encouraged.
Problems
Circular dependencies can cause many unwanted effects in software programs. Most problematic from a software design point of view is the tight coupling of the mutually dependent modules which reduces or makes impossible the separate re-use of a single module.
Circular dependencies can cause a domino effect when a small local change in one module spreads into other modules and has unwanted global effects (program errors, compile errors). Circular dependencies can also result in infinite recursions or other unexpected failures.
Circular dependencies may also cause memory leaks by preventing certain automatic garbage collectors (those that use reference counting) from deallocating unused objects.
Causes and solutions
In very large software designs, software engineers may lose the context and inadvertently introduce circular dependencies. There are tools to analyze software and find unwanted circular dependencies.
Circular dependencies can be introduced when implementing callback functionality. This can be avoided by applying design patterns like the observer pattern.
See also
Acyclic dependencies principle
Dependency hell |
https://en.wikipedia.org/wiki/Aequorin | Aequorin is a calcium-activated photoprotein isolated from the hydrozoan Aequorea victoria. Its bioluminescence was studied decades before the protein was isolated from the animal by Osamu Shimomura in 1962. In the animal, the protein occurs together with the green fluorescent protein to produce green light by resonant energy transfer, while aequorin by itself generates blue light.
Discussions of "jellyfish DNA" that can make "glowing" animals often refer to transgenic animals that express the green fluorescent protein, not aequorin, although both originally derive from the same animal.
Apoaequorin, the protein portion of aequorin, is an ingredient in the dietary supplement Prevagen. The US Federal Trade Commission (FTC) has charged the maker with false advertising for its memory improvement claims.
Discovery
Work on aequorin began with E. Newton Harvey in 1921. Though Harvey was unable to demonstrate a classical luciferase-luciferin reaction, he showed that water could produce light from dried photocytes and that light could be produced even in the absence of oxygen. Later, Osamu Shimomura began work into the bioluminescence of Aequorea in 1961. This involved tedious harvesting of tens of thousands of jellyfish from the docks in Friday Harbor, Washington. It was determined that light could be produced from extracts with seawater, and more specifically, with calcium. It was also noted during the extraction the animal creates green light due to the presence of the green fluorescent protein, which changes the native blue light of aequorin to green.
While the main focus of his work was on the bioluminescence, Shimomura and two others, Martin Chalfie and Roger Tsien, were awarded the Nobel Prize in 2008 for their work on green fluorescent proteins.
Structure
Aequorin is a holoprotein composed of two distinct units, the apoprotein that is called apoaequorin, which has an approximate molecular weight of 21 kDa, and the prosthetic group coelenterazine, the luciferin |
https://en.wikipedia.org/wiki/Thorne%E2%80%93Hawking%E2%80%93Preskill%20bet | The Thorne–Hawking–Preskill bet was a public bet on the outcome of the black hole information paradox made in 1997 by physics theorists Kip Thorne and Stephen Hawking on the one side, and John Preskill on the other, according to the document they signed 6 February 1997, as shown in Hawking's The Universe in a Nutshell.
Overview
Thorne & Hawking argued that since general relativity made it impossible for black holes to radiate, and lose information, the mass-energy and information carried by Hawking radiation must be "new", and must not originate from inside the black hole event horizon. Since this contradicted the idea under quantum mechanics of microcausality, quantum mechanics would need to be rewritten. Preskill argued the opposite, that since quantum mechanics suggests that the information emitted by a black hole relates to information that fell in at an earlier time, the view of black holes given by general relativity must be modified in some way. The winning side of the bet would receive an encyclopedia of their choice, "from which information can be retrieved at will".
In 2004, Hawking announced that he was conceding the bet, and that he now believed that black hole horizons should fluctuate and leak information, in doing so providing Preskill with a copy of Total Baseball, The Ultimate Baseball Encyclopedia. Comparing the useless information obtainable from a black hole to "burning an encyclopedia", Hawking later joked, "I gave John an encyclopedia of baseball, but maybe I should just have given him the ashes." Thorne, however, remained unconvinced of Hawking's proof and declined to contribute to the award. Hawking's argument that he solved the paradox has not yet been wholly accepted by the scientific community, and a consensus has not yet been reached that Hawking provided a strong enough argument that this is in fact what happens.
Hawking had earlier speculated that the singularity at the centre of a black hole could form a bridge to a "baby universe", |
https://en.wikipedia.org/wiki/Sigma%20model | In physics, a sigma model is a field theory that describes the field as a point particle confined to move on a fixed manifold. This manifold can be taken to be any Riemannian manifold, although it is most commonly taken to be either a Lie group or a symmetric space. The model may or may not be quantized. An example of the non-quantized version is the Skyrme model; it cannot be quantized due to non-linearities of power greater than 4. In general, sigma models admit (classical) topological soliton solutions, for example, the Skyrmion for the Skyrme model. When the sigma field is coupled to a gauge field, the resulting model is described by Ginzburg–Landau theory. This article is primarily devoted to the classical field theory of the sigma model; the corresponding quantized theory is presented in the article titled "non-linear sigma model".
Overview
The sigma model was introduced by ; the name σ-model comes from a field in their model corresponding to a spinless meson called , a scalar meson introduced earlier by Julian Schwinger. The model served as the dominant prototype of spontaneous symmetry breaking of O(4) down to O(3): the three axial generators broken are the simplest manifestation of chiral symmetry breaking, the surviving unbroken O(3) representing isospin.
In conventional particle physics settings, the field is generally taken to be SU(N), or the vector subspace of quotient of the product of left and right chiral fields. In condensed matter theories, the field is taken to be O(N). For the rotation group O(3), the sigma model describes the isotropic ferromagnet; more generally, the O(N) model shows up in the quantum Hall effect, superfluid Helium-3 and spin chains.
In supergravity models, the field is taken to be a symmetric space. Since symmetric spaces are defined in terms of their involution, their tangent space naturally splits into even and odd parity subspaces. This splitting helps propel the dimensional reduction of Kaluza–Klein theories.
In |
https://en.wikipedia.org/wiki/Program%20Design%20Language | Program Design Language (or PDL, for short) is a method for designing and documenting methods and procedures in software. It is related to pseudocode, but unlike pseudocode, it is written in plain language without any terms that could suggest the use of any programming language or library.
PDL was originally developed by the company Caine, Farber & Gordon and has been modified substantially since they published their initial paper on it in 1975. It has been described in some detail by Steve McConnell in his book Code Complete.
See also
Pseudocode
FLOW CHART
External links
Using PDL for Code Design and Documentation
PDL/81 Home Page by Caine, Farber & Gordon, Inc.
C STYLE GUIDE from Goddard Space Flight Center, National Aeronautics and Space Administration.
Algorithm description languages |
https://en.wikipedia.org/wiki/ISO%2013567 | ISO 13567 is an international computer-aided design (CAD) layer standard.
Standard parts
The standard is divided into three parts:
ISO 13567-1:2017
Technical product documentation — Organization and naming of layers for CAD — Part 1: Overview and principles
ISO 13567-2:2017
Technical product documentation — Organization and naming of layers for CAD — Part 2: Concepts, format and codes used in construction documentation
ISO/TR 13567-3:1999 (withdrawn September 2015)
Technical product documentation — Organization and naming of layers for CAD — Part 3: Application of ISO 13567-1 and ISO 13567-2
Standard has been developed by Technical Committee TC 10 (Technical product documentation) Subcommittee SC 8 (Construction documentation); Refer. ICS: 01.110; 35.240.10.
Structure of layer names
CAD layer names are structured as a series of mandatory and optional fixed length fields, composed as a continuous alpha-numerical text string.
Mandatory fields
Agent responsible (clause 6.1)
(2 characters, indicating the person or organisation responsible for the layer information—manufacturer,
A- architect
A2 architect#2 on the same project
B- building surveyors
C- civil engineers
E- electrical engineers
F- facility engineers
G- GIS engineers and land surveyors
H- heating and ventilating engineers
I- interior designers
L- landscape architects
Q- quantity surveyors
S- structural engineers
T- town and country planners
W- contractors
X- sub-contractors
Y- specialist designers
Element (clause 6.2)
(6 characters, indicating the functional parts of construction works or structure): follows a classification system like SfB building codes or Uniclass codes;
Presentation (clause 6.3)
(2 characters, related to the information graphical presentation)
-- whole model and drawing page,
E- element graphics (Model space)
T- text (M)
H- hatching (M)
D- dimensions (M)
J- section/detail marks (M)
K- revision marks (M)
G- Grid graphic and dimension (M)
U- user red lines & co |
https://en.wikipedia.org/wiki/Passenger%20virus | A passenger virus is a virus that is frequently found in samples from diseased tissue, such as tumours, but is not a contributing factor in causing the disease.
Experimental demonstration of passenger status
Proving that a virus has no causative role can be difficult. Although none of the following signs is definitive, evidence that a virus found in diseased tissue might be passenger only rather than a causative agent includes:
injection of the virus into healthy animals without causing disease;
the absence of the virus at the earliest stages of the disease;
curing the viral infection using antiviral drugs or vaccination with no effect on the course of the disease.
Examples
A well-established example is lactate dehydrogenase virus, which is often found in mouse tumours. GB virus C and Chandipura virus are possible examples in humans. It has also been suggested that a virus related to Alcelaphine herpesvirus 1 is a passenger virus that, unlike AHV1 itself, does not cause bovine malignant catarrhal fever. The discredited Duesberg hypothesis posits that HIV is a passenger virus in the etiology of AIDS. |
https://en.wikipedia.org/wiki/Namesco | Namesco Ltd (names.co.uk) provides professional online services for individuals and businesses including domain name registration, web hosting, website building tools, email services, ecommerce solutions and a range of managed and unmanaged servers.
History
Namesco was founded by Richard and Rachel Suthering as a small Internet startup named "Names.co Internet Services Limited" originally based in North East England. In 1997 another Internet startup was founded by Kevin Savage, Jason Smith and John Sewell named Phase8.com "Webcall.com Limited" based in Worcester.
Following the dot com boom, Names.co Internet Services Limited became a Public Limited Company and floated on the London Unlisted Securities Market with a new name of Namesco Internet Plc in 2000. The following year, they acquired Phase8.com "Webcall.com Limited" for the sum of £2,450,000.
Despite acquiring smaller web hosting companies and resellers along the way, including SmartChoiceNet, the "publicly quoted" Namesco struggled to be viable citing the increasingly competitive nature of the domain name and web hosting business, and the additional costs of maintaining listed status as the reasons for a lack of profitability.
In 2002, it was rumoured that Ian Gowrie-Smith, Australian chairman of drug company SkyePharma was planning a reverse takeover of Namesco with the assistance of its chief executive and finance director, David Lees.
Trading of Namesco shares on AIM were suspended on 19 December 2003 prior to the announcement of Gowrie-Smith’s action. A Vietnamese gold mining company, Larchland, was injected into the company in a £19.6million reverse takeover deal that saw the business renamed as Triple Junction PLC. Namesco was hived down into a subsidiary and sold to Womerah Limited.
As a privately owned company, Namesco then had the capital to make new acquisitions as part of their growth strategy. In July 2004, they acquired NamesWeb; a small domain and web hosting business, and on 17 Septemb |
https://en.wikipedia.org/wiki/Autoload | In computer programming, autoloading is the capability of loading and linking portions of a program from mass storage automatically when needed, so that the programmer is not required to define or include those portions of the program explicitly. Many high-level programming languages include autoload capabilities, which sacrifice some run-time speed for ease of coding and speed of initial compilation/linking.
Typical autoload systems intercept procedure calls to undefined subroutines. The autoloader searches through a path of directories in the computer's file system, to find a file containing source or object code that defines the subroutine. The autoloader then loads and links the file, and hands control back to the main program so that the subroutine gets executed as if it had already been defined and linked before the call.
Many interactive and high-level languages operate in this way. For example, IDL includes a primitive path searcher, and Perl allows individual modules to determine how and whether autoloading should occur. The Unix shell may be said to consist almost entirely of an autoloader, as its main job is to search a path of directories to load and execute command files. In PHP 5, autoload functionality is triggered when referencing an undefined class. One or more autoload functions—implemented as the __autoload magic function or any function registered to the SPL autoload stack—is called and given the opportunity to define the class, usually by loading the file it is defined in.
PHP
spl_autoload_register(function ($class) {
$file = 'src/' . str_replace('\\', '/', $relative_class) . '.php';
if (file_exists($file)) {
require $file;
}
});
External links
PSR-4 Improved Autoloading Standard
Autoloading Classes in PHP
spl_autoload_register in PHP
Programming constructs |
https://en.wikipedia.org/wiki/Quantum%20noise | Quantum noise is noise arising from the indeterminate state of matter in accordance with fundamental principles of quantum mechanics, specifically the uncertainty principle and via zero-point energy fluctuations. Quantum noise is due to the apparently discrete nature of the small quantum constituents such as electrons, as well as the discrete nature of quantum effects, such as photocurrents.
Quantified noise is similar to classical noise theory and will not always return an asymmetric spectral density.
Shot noise as coined by J. Verdeyen is a form of quantum noise related to the statistics of photon counting, the discrete nature of electrons, and intrinsic noise generation in electronics. In contrast to shot noise, the quantum mechanical uncertainty principle sets a lower limit to a measurement. The uncertainty principle requires any amplifier or detector to have noise.
Macroscopic manifestations of quantum phenomena are easily disturbed, so quantum noise is mainly observed in systems where conventional sources of noise are suppressed. In general, noise is uncontrolled random variation from an expected value and is typically unwanted. General causes are thermal fluctuations, mechanical vibrations, industrial noise, fluctuations of voltage from a power supply, thermal noise due to Brownian motion, instrumentation noise, a laser's output mode deviating from the desired mode of operation, etc. If present, and unless carefully controlled, these other noise sources typically dominate and mask quantum noise.
In astronomy, a device which pushes against the limits of quantum noise is the LIGO gravitational wave observatory.
A Heisenberg microscope
Quantum noise can be illustrated by considering a Heisenberg microscope where an atom's position is measured from the scattering of photons. The uncertainty principle is given as,
Where the is the uncertainty in an atom's position, and the is the uncertainty of the momentum or sometimes called the backaction (momentum |
https://en.wikipedia.org/wiki/Descartes%27%20rule%20of%20signs | In mathematics, Descartes' rule of signs, first described by René Descartes in his work La Géométrie, is a technique for getting information on the number of positive real roots of a polynomial. It asserts that the number of positive roots is at most the number of sign changes in the sequence of polynomial's coefficients (omitting the zero coefficients), and that the difference between these two numbers is always even. This implies, in particular, that if the number of sign changes is zero or one, then there are exactly zero or one positive roots, respectively.
By a linear fractional transformation of the variable, one may use Descartes' rule of signs for getting a similar information on the number of roots in any interval. This is the basic idea of Budan's theorem and Budan–Fourier theorem. By repeating the division of an interval into two intervals, one gets eventually a list of disjoint intervals containing together all real roots of the polynomial, and containing each exactly one real root. Descartes rule of signs and linear fractional transformations of the variable are, nowadays, the basis of the fastest algorithms for computer computation of real roots of polynomials (see real-root isolation).
Descartes himself used the transformation for using his rule for getting information of the number of negative roots.
Descartes' rule of signs
Positive roots
The rule states that if the nonzero terms of a single-variable polynomial with real coefficients are ordered by descending variable exponent, then the number of positive roots of the polynomial is either equal to the number of sign changes between consecutive (nonzero) coefficients, or is less than it by an even number. A root of multiplicity is counted as roots.
In particular, if the number of sign changes is zero or one, the number of positive roots equals the number of sign changes.
Negative roots
As a corollary of the rule, the number of negative roots is the number of sign changes after multiplying |
https://en.wikipedia.org/wiki/General%20Boy | General Boy is a character created around 1975 by new wave band Devo. He is usually seen portrayed by Robert Mothersbaugh, Sr., the father of Devo's lead singer Mark Mothersbaugh, former drummer Jim Mothersbaugh, and lead guitarist Bob Mothersbaugh.
History
General Boy, along with his son Booji Boy, were first introduced in the 1976 short film The Truth About De-Evolution. Both characters have made numerous appearances in various short films, music videos, written propaganda and even concerts by the band.
Both characters were also incorporated into Devo's 1996 PC CD-ROM video game Devo Presents Adventures of the Smart Patrol (with Booji Boy being re-christened "Boogie Boy"). The booklet of the game claims that the Boys' true last name was Rothwell and that Booji Boy's true name was Craig Allen Rothwell.
The game's booklet also contained more information about General Boy's back story:
For reasons unknown, General Boy was portrayed by actor Tom Finnegan in the game (it is likely that this was because Robert was not available). Robert Mothersbaugh, Sr. reprised his role as General Boy at the annual 2002 DEVOtional event held in Cleveland, Ohio.
Under the General Boy pseudonym, Robert Mothersbaugh, Sr. is credited as a co-writer on "Enough Said", the closing track of Devo's 1981 album New Traditionalists.
Robert Mothersbaugh, Sr. died in 2016. |
https://en.wikipedia.org/wiki/Magic%20%28programming%29 | In the context of computer programming, magic is an informal term for abstraction; it is used to describe code that handles complex tasks while hiding that complexity to present a simple interface. The term is somewhat tongue-in-cheek, and often carries bad connotations, implying that the true behavior of the code is not immediately apparent. For example, Perl's polymorphic typing and closure mechanisms are often called "magic". The term implies that the hidden complexity is at least in principle understandable, in contrast to black magic and deep magic (see Variants), which describe arcane techniques that are deliberately hidden or extremely difficult to understand. However, the term can also be applied endearingly, suggesting a "charm" about the code. The action of such abstractions is described as being done "automagically", a portmanteau of "automatically" and "magically".
Referential opacity
"Magic" refers to procedures which make calculations based on data not clearly provided to them, by accessing other modules, memory positions or global variables that they are not supposed to (in other words, they are not referentially transparent). According to most recent software architecture models, even when using structured programming, it is usually preferred to make each function behave the same way every time the same arguments are passed to it, thereby following one of the basic principles of functional programming. When a function breaks this rule, it is often said to contain "magic".
A simplified example of negative magic is the following code in PHP:
function magic()
{
global $somevariable;
echo $somevariable;
}
$somevariable = true;
magic();
While the code above is clear and maintainable, if it is seen in a large project, it is often hard to understand where the function magic() gets its value from. It is preferred to write that code using the following concept:
function noMagic($myvariable)
{
echo $myvariable;
}
$somevariable = true;
|
https://en.wikipedia.org/wiki/Applied%20physics | Applied physics is the application of physics to solve scientific or engineering problems. It is usually considered a bridge or a connection between physics and engineering.
"Applied" is distinguished from "pure" by a subtle combination of factors, such as the motivation and attitude of researchers and the nature of the relationship to the technology or science that may be affected by the work. Applied physics is rooted in the fundamental truths and basic concepts of the physical sciences but is concerned with the utilization of scientific principles in practical devices and systems and with the application of physics in other areas of science and high technology.
Examples of research and development areas
Accelerator physics
Acoustics
Atmospheric physics
Biophysics
Brain–computer interfacing
Chemistry
Chemical physics
Differentiable programming
Artificial intelligence
Scientific computing
Engineering physics
Chemical engineering
Electrical engineering
Electronics
Sensors
Transistors
Materials science and engineering
Metamaterials
Nanotechnology
Semiconductors
Thin films
Mechanical engineering
Aerospace engineering
Astrodynamics
Electromagnetic propulsion
Fluid mechanics
Military engineering
Lidar
Radar
Sonar
Stealth technology
Nuclear engineering
Fission reactors
Fusion reactors
Optical engineering
Photonics
Cavity optomechanics
Lasers
Photonic crystals
Geophysics
Materials physics
Medical physics
Health physics
Radiation dosimetry
Medical imaging
Magnetic resonance imaging
Radiation therapy
Microscopy
Scanning probe microscopy
Atomic force microscopy
Scanning tunneling microscopy
Scanning electron microscopy
Transmission electron microscopy
Nuclear physics
Fission
Fusion
Optical physics
Nonlinear optics
Quantum optics
Plasma physics
Quantum technology
Quantum computing
Quantum cryptography
Renewable energy
Space physics
Spectroscopy
See also
Applied science
Applied mathematics
Engineering
Engineering Physics
High Technology |
https://en.wikipedia.org/wiki/Problem%20of%20Apollonius | In Euclidean plane geometry, Apollonius's problem is to construct circles that are tangent to three given circles in a plane (Figure 1). Apollonius of Perga (c. 262 190 BC) posed and solved this famous problem in his work (, "Tangencies"); this work has been lost, but a 4th-century AD report of his results by Pappus of Alexandria has survived. Three given circles generically have eight different circles that are tangent to them (Figure 2), a pair of solutions for each way to divide the three given circles in two subsets (there are 4 ways to divide a set of cardinality 3 in 2 parts).
In the 16th century, Adriaan van Roomen solved the problem using intersecting hyperbolas, but this solution does not use only straightedge and compass constructions. François Viète found such a solution by exploiting limiting cases: any of the three given circles can be shrunk to zero radius (a point) or expanded to infinite radius (a line). Viète's approach, which uses simpler limiting cases to solve more complicated ones, is considered a plausible reconstruction of Apollonius' method. The method of van Roomen was simplified by Isaac Newton, who showed that Apollonius' problem is equivalent to finding a position from the differences of its distances to three known points. This has applications in navigation and positioning systems such as LORAN.
Later mathematicians introduced algebraic methods, which transform a geometric problem into algebraic equations. These methods were simplified by exploiting symmetries inherent in the problem of Apollonius: for instance solution circles generically occur in pairs, with one solution enclosing the given circles that the other excludes (Figure 2). Joseph Diaz Gergonne used this symmetry to provide an elegant straightedge and compass solution, while other mathematicians used geometrical transformations such as reflection in a circle to simplify the configuration of the given circles. These developments provide a geometrical setting for algebraic |
https://en.wikipedia.org/wiki/Apyrase | Apyrase (, ATP-diphosphatase, adenosine diphosphatase, ADPase, ATP diphosphohydrolase) is a calcium-activated plasma membrane-bound enzyme (magnesium can also activate it) () that catalyses the hydrolysis of ATP to yield AMP and inorganic phosphate. Two isoenzymes are found in commercial preparations from S. tuberosum. One with a higher ratio of substrate selectivity for ATP:ADP (approx 10) and another with no selectivity (ratio 1).
It can also act on ADP and other nucleoside triphosphates and diphosphates with the general reaction being NTP -> NDP + Pi -> NMP + 2Pi. This is the same activity that has been employed in the degradation of unincorporated nucleosides during pyrosequencing.
The salivary apyrases of blood-feeding arthropods are nucleotide hydrolysing enzymes that are implicated in the inhibition of host platelet aggregation through the hydrolysis of extracellular adenosine diphosphate. |
https://en.wikipedia.org/wiki/Geron%20Corporation | Geron Corporation is a biotechnology company located in Foster City, California, which specializes in developing and commercializing therapeutic products for cancer that inhibit telomerase.
Company information
Geron, based in Foster City, California, was founded by gerontologist Mary C. West and Michael D. West, now CEO of AgeX Therapeutics. They secured initial venture capital investments in the company from Kleiner Perkins Caufield & Byers and Venrock. The company was incorporated in 1990 and began doing business in 1992. John A. Scarlett was appointed CEO in 2011.
The company's Scientific and Clinical Advisory Board has included Nobel laureates James Watson, Gunter Blobel, and Carol Greider, and Leonard Hayflick, known for discovering that human cells divide for a limited number of times in vitro (called the Hayflick limit).
In 2017, Geron staff received the highest median pay in California, at $500,250.
Drug candidates
Cancer therapies
Geron Corporation has sponsored human clinical trials of several potential anti-cancer products.
Imetelstat (GRN163L) is a drug that targets telomerase. In studies conducted at Johns Hopkins University, GRN163L was active against both CD138+ and CD138neg cancer stem cells and eliminated the colony forming potential of both by five weeks. Similarly, GRN163L inhibited the in vitro clonogenic growth of CD138neg Multiple Myeloma Cancer Stem Cells isolated from the bone marrow aspirates of patients with multiple myeloma. On November 3, 2014, the FDA removed the full clinical hold on imetelstat and declared the company's clinical development plan as acceptable. In 2014, Geron licensed imetelstat to Janssen Biotech. In 2017, imetelstat was granted fast track status by the FDA for certain patients with myelodysplastic syndrome. In 2018, Janssen Biotech returned the rights to imetelstat to Geron. Imetelstat is currently in two Phase 3 trials: NCT02598661, a study of the drug's ability to reduce the transfusion requirements of pat |
https://en.wikipedia.org/wiki/Optimum%20%22L%22%20filter | The Optimum "L" filter (also known as a Legendre–Papoulis filter) was proposed by Athanasios Papoulis in 1958. It has the maximum roll off rate for a given filter order while maintaining a monotonic frequency response. It provides a compromise between the Butterworth filter which is monotonic but has a slower roll off and the Chebyshev filter which has a faster roll off but has ripple in either the passband or stopband. The filter design is based on Legendre polynomials which is the reason for its alternate name and the "L" in Optimum "L".
See also
Bessel filter
Elliptic filter |
https://en.wikipedia.org/wiki/NetWare%20Core%20Protocol | The NetWare Core Protocol (NCP) is a network protocol used in some products from Novell, Inc. It is usually associated with the client-server operating system Novell NetWare which originally supported primarily MS-DOS client stations, but later support for other platforms such as Microsoft Windows, the classic Mac OS, Linux, Windows NT, Mac OS X, and various flavors of Unix was added.
The NCP is used to access file, print, directory, clock synchronization, messaging, remote command execution and other network service functions. It originally took advantage of an easy network configuration and a little memory footprint of the IPX/SPX protocol stack. Since 1991 the TCP/IP implementation is available.
Novell eDirectory uses NCP for synchronizing data changes between the servers in a directory service tree.
Technical information
The original IPX/SPX implementation was provided only for Novell NetWare platform and now is obsolete. The TCP/IP implementation uses TCP/UDP port 524 and relies on SLP for name resolution.
For NCP operation in IPX/SPX networks the bare IPX protocol was used with Packet Type field set to 17. On the workstation (client station) side the IPX socket number of 0x4003 was used, on the server side the socket number of 0x0451.
The NCP PDU has the following structure:
The NCP Type field determines the type of operation:
Individual requests are identified by the Sequence Number (modulo 256). The Connection Number identifies an individual client station connection on the server. Novell Netware servers of version up to 2.x supported up to 255 connections and the Connection Number occupied only 1 octet. Later it was extended to 2 octets. Task number has value 3 in requests and 1 in replies. The Data field starts with NCP Function number octet which distinguishes individual services.
The contents and the length of the rest of the Data field depends on the NCP Function.
Client-side implementations
Novell Client for Windows Vista from Novell.
Nov |
https://en.wikipedia.org/wiki/Operation%20Ruthless | Operation Ruthless was the name of a deception operation devised by Ian Fleming in the British Admiralty during World War II, in an attempt to gain access to German Naval Enigma codebooks.
Background
With the help of their Polish allies, British codebreakers at Bletchley Park had considerable success in decoding the Enigma-enciphered traffic of the German air force, army and intelligence and counter-espionage service (Abwehr), but had made little progress with German naval messages. The methods of communicating the choice and starting positions, of Enigma's rotors, the indicator, were much more complex for naval messages. In 1940 Dilly Knox, the veteran World War I codebreaker, Frank Birch, head of Bletchley Park's German Naval Department, and the two leading codebreakers, Alan Turing and Peter Twinn knew that getting hold of the German Navy Enigma documentation was their best chance of making progress in breaking the code.
The Royal Navy's Operational Intelligence Centre (OIC) was a leading user of Ultra intelligence from Bletchley Park's decrypts. Lieutenant Commander Ian Fleming of the Admiralty's Naval Intelligence Division, who later wrote the James Bond novels, was the personal assistant to the Director of Naval Intelligence, Rear Admiral John Godfrey. Fleming liaised with the naval department at Bletchley Park, visiting about twice a month, and was well aware of this problem.
The plan
On 12 September 1940, Fleming wrote a note to Godfrey which read:
I suggest we obtain the loot by the following means:
1. Obtain from Air Ministry an air-worthy German bomber.
2. Pick a tough crew of five, including a pilot, W/T operator and word-perfect German speaker. Dress them in German Air Force uniform, add blood and bandages to suit.
3. Crash plane in the Channel after making S.O.S. to rescue service in P/L.
4. Once aboard rescue boat, shoot German crew, dump overboard, bring rescue boat back to English port.
In order to increase the chances of capturing |
https://en.wikipedia.org/wiki/DEEP2%20Redshift%20Survey | The DEEP2 Survey or DEEP2 was a two-phased Redshift survey of the Redshift z=~1 universe (where z= a measure of speed and by extension, the distance from earth). It used the twin 10 metre Keck telescopes in Hawaii (the world's second largest optical telescope) to measure the spectra and hence the redshifts of approximately 50,000 galaxies. It was the first project to study galaxies in the distant Universe with the resolution of local surveys like the Sloan Digital Sky Survey and was completed in 2013. |
https://en.wikipedia.org/wiki/Antibody%20testing | Antibody testing may refer to:
Serological testing, tests that detect specific antibodies in the blood
Immunoassay, tests that use antibodies to detect substances
Antibody titer, tests that measure the amount of a specific antibody in a sample
Antibodies
Biological techniques and tools |
https://en.wikipedia.org/wiki/Archive%20site | In web archiving, an archive site is a website that stores information on webpages from the past for anyone to view.
Common techniques
Two common techniques for archiving websites are using a web crawler or soliciting user submissions:
Using a web crawler: By using a web crawler (e.g., the Internet Archive) the service will not depend on an active community for its content, and thereby can build a larger database faster. However, web crawlers are only able to index and archive information the public has chosen to post to the Internet, or that is available to be crawled, as website developers and system administrators have the ability to block web crawlers from accessing [certain] web pages (using a robots.txt).
User submissions: While it can be difficult to start user submission services due to potentially low rates of user submissions, this system can yield some of the best results. By crawling web pages one is only able to obtain the information the public has chosen to post online; however, potential content providers may not bother to post certain information, assuming no one would be interested in it, because they lack a proper venue in which to post it, or because of copyright concerns. However, users who see someone wants their information may be more apt to submit it.
Examples
Google Groups
On 12 February 2001, Google acquired the usenet discussion group archives from Deja.com and turned it into their Google Groups service. They allow users to search old discussions with Google's search technology, while still allowing users to post to the mailing lists.
Internet Archive
The Internet Archive is building a compendium of websites and digital media. Starting in 1996, the Archive has been employing a web crawler to build up their database. It is one of the best known archive sites.
NBCUniversal Archives
NBCUniversal Archives offer access to exclusive content from NBCUniversal and its subsidiaries. Their NBCUniversal Archives website provides easy viewing |
https://en.wikipedia.org/wiki/Paraxial%20approximation | In geometric optics, the paraxial approximation is a small-angle approximation used in Gaussian optics and ray tracing of light through an optical system (such as a lens).
A paraxial ray is a ray which makes a small angle (θ) to the optical axis of the system, and lies close to the axis throughout the system. Generally, this allows three important approximations (for θ in radians) for calculation of the ray's path, namely:
The paraxial approximation is used in Gaussian optics and first-order ray tracing. Ray transfer matrix analysis is one method that uses the approximation.
In some cases, the second-order approximation is also called "paraxial". The approximations above for sine and tangent do not change for the "second-order" paraxial approximation (the second term in their Taylor series expansion is zero), while for cosine the second order approximation is
The second-order approximation is accurate within 0.5% for angles under about 10°, but its inaccuracy grows significantly for larger angles.
For larger angles it is often necessary to distinguish between meridional rays, which lie in a plane containing the optical axis, and sagittal rays, which do not. |
https://en.wikipedia.org/wiki/Rectifiable%20set | In mathematics, a rectifiable set is a set that is smooth in a certain measure-theoretic sense. It is an extension of the idea of a rectifiable curve to higher dimensions; loosely speaking, a rectifiable set is a rigorous formulation of a piece-wise smooth set. As such, it has many of the desirable properties of smooth manifolds, including tangent spaces that are defined almost everywhere. Rectifiable sets are the underlying object of study in geometric measure theory.
Definition
A Borel subset of Euclidean space is said to be -rectifiable set if is of Hausdorff dimension , and there exist a countable collection of continuously differentiable maps
such that the -Hausdorff measure of
is zero. The backslash here denotes the set difference. Equivalently, the may be taken to be Lipschitz continuous without altering the definition. Other authors have different definitions, for example, not requiring to be -dimensional, but instead requiring that is a countable union of sets which are the image of a Lipschitz map from some bounded subset of .
A set is said to be purely -unrectifiable if for every (continuous, differentiable) , one has
A standard example of a purely-1-unrectifiable set in two dimensions is the Cartesian product of the Smith–Volterra–Cantor set times itself.
Rectifiable sets in metric spaces
gives the following terminology for m-rectifiable sets E in a general metric space X.
E is rectifiable when there exists a Lipschitz map for some bounded subset of onto .
E is countably rectifiable when E equals the union of a countable family of rectifiable sets.
E is countably rectifiable when is a measure on X and there is a countably rectifiable set F such that .
E is rectifiable when E is countably rectifiable and
E is purely unrectifiable when is a measure on X and E includes no rectifiable set F with .
Definition 3 with and comes closest to the above definition for subsets of Euclidean spaces.
Notes |
https://en.wikipedia.org/wiki/Acidogenesis | Acidogenesis is the second stage in the four stages of anaerobic digestion:
Hydrolysis: A chemical reaction where particulates are solubilized and large polymers converted into simpler monomers;
Acidogenesis: A biological reaction where simple monomers are converted into volatile fatty acids;
Acetogenesis: A biological reaction where volatile fatty acids are converted into acetic acid, carbon dioxide, and hydrogen
Methanogenesis: A biological reaction where acetates are converted into methane and carbon dioxide, while hydrogen is consumed.
Anaerobic digestion is a complex biochemical process of biologically mediated reactions by a consortium of microorganisms to convert organic compounds into methane and carbon dioxide. It is a stabilization process, reducing odor, pathogens, and mass reduction.
Hydrolytic bacteria form a variety of reduced end-products from the fermentation of a given substrate. One fundamental question that arises concerns the metabolic features that control carbon and electron flow to a given reduced end-product during pure culture and mixed methanogenic cultures of hydrolytic bacteria. Thermoanaerobium brockii is a representative thermophilic, hydrolytic bacterium, which ferments glucose, via the Embden–Meyerhof Parnas Pathway. T. brockii is an atypical hetero-lactic acid bacterium because it forms molecular hydrogen (H2), in addition to lactic acid and ethanol. The reduced end-products of glucose fermentation are enzymatically formed from pyruvate, via the following mechanisms: lactate by fructose 1-6 all-phosphate (F6P) activated lactate dehydrogenase; H2 by pyruvate ferredoxin oxidoreductase and hydrogenase; and ethanol via NADH- and NADPH-linked alcohol dehydrogenase.
By its side, the acidogenic activity was found in the early 20th century, but it was not until the mid-1960s that the engineering of phases separation was assumed in order to improve the stability and waste digesters treatment. In this phase, complex molecules (carbohydra |
https://en.wikipedia.org/wiki/Lactase%20persistence | Lactase persistence is the continued activity of the lactase enzyme in adulthood, allowing the digestion of lactose in milk. In most mammals, the activity of the enzyme is dramatically reduced after weaning. In some human populations though, lactase persistence has recently evolved as an adaptation to the consumption of nonhuman milk and dairy products beyond infancy. Lactase persistence is very high among northern Europeans, especially Irish people. Worldwide, most people are lactase non-persistent, and are affected by varying degrees of lactose intolerance as adults. However, lactase persistence and lactose intolerance do not always overlap.
Global distribution of the phenotype
The distribution of the lactase persistence (LP) phenotype, or the ability to digest lactose into adulthood, is not homogeneous in the world. Lactase persistence frequencies are highly variable. In Europe, the distribution of the lactase persistence phenotype is clinal, with frequencies ranging from 15–54% in the south-east to 89–96% in the north-west. For example, only 17% of Greeks and 14% of Sardinians are predicted to possess this phenotype, while around 80% of Finns and Hungarians and 100% of Irish people are predicted to be lactase persistent. Similarly, the frequency of lactase-persistence is clinal in India, a 2011 study of 2,284 individuals identifying a prevalence of LP in the Ror community, of Haryana, in the North West, of 48.95%, declining to 1.5% in the Andamanese, of the South East, and 0.8% in the Tibeto-Burman communities, of the North East.
High frequencies of lactase persistence are also found in some places in Sub-Saharan Africa and in the Middle East. But the most common situation is intermediate to low lactase persistence: intermediate (11 to 32%) in Central Asia, low (<=5%) in Native Americans, East Asians, most Chinese populations and some African populations.
In Africa, the distribution of lactase persistence is "patchy": high variations of frequency are observ |
https://en.wikipedia.org/wiki/Monterey%20Canyon | Monterey Canyon, or Monterey Submarine Canyon, is a submarine canyon in Monterey Bay, California with steep canyon walls measuring a full in height from bottom to top, which height/depth rivals the depth of the Grand Canyon itself. It is the largest such submarine canyon along the West coast of the North American continent, and was formed by the underwater erosion process known as turbidity current erosion. Many questions remain unresolved regarding the exact nature of its origins, and as such it is the subject of several ongoing geological and marine life studies being carried out by scientists stationed at the nearby Monterey Bay Aquarium Research Institute, the Moss Landing Marine Laboratories, and other oceanographic institutions.
Monterey Canyon begins at Moss Landing, California, which is situated along the middle of the coast of Monterey Bay, and extends horizontally under the Pacific Ocean where it terminates at the Monterey Canyon submarine fan, reaching depths of up to 3,600 m (11,800 ft) below surface level at its downstream mouth. It is a part of the greater Monterey Bay Canyon System, which consists of Monterey, Soquel and Carmel Canyons. The canyon's depth and nutrient availability (due to the regular influx of nutrient-rich sediment) provide a habitat suitable for many marine life forms.
The Soquel Canyon State Marine Conservation Area protects a side-branch of the Monterey Submarine Canyon. Like an underwater park, this marine protected area helps conserve ocean wildlife and marine ecosystems.
Geomorphology
While the erosion process of turbidity current erosion which once carved out the submarine Monterey Canyon is well known, the cause of the great depth and length of this canyon, obviously carved out millions of years ago, and the unusually large size of the sedimentary deposit (fan) at its underwater mouth 95 miles West of Monterey, have all been a cause for some speculation. Typically submarine canyons of this depth and length which c |
https://en.wikipedia.org/wiki/Ophcrack | Ophcrack is a free open-source (GPL licensed) program that cracks Windows log-in passwords by using LM hashes through rainbow tables. The program includes the ability to import the hashes from a variety of formats, including dumping directly from the SAM files of Windows. On most computers, ophcrack can crack most passwords within a few minutes.
Rainbow tables for LM hashes are provided for free by the developers. By default, ophcrack is bundled with tables that allow it to crack passwords no longer than 14 characters using only alphanumeric characters. Available for free download are four Windows XP tables and four Windows Vista tables.
Objectif Sécurité has even larger tables for purchase that are intended for professional use. Larger rainbow tables are NTLM hash for cracking Windows Vista/Windows 7.
Ophcrack is also available as Live CD distributions, which automates the retrieval, decryption, and cracking of passwords from a Windows system. One Live CD distribution is available for Windows XP and lower and another for Windows Vista and Windows 7. The Live CD distributions of ophcrack are built with SliTaz GNU/Linux.
Starting with version 2.3, Ophcrack also cracks NTLM hashes. This is necessary if the generation of the LM hash is disabled (this is default for Windows Vista) or if the password is longer than 14 characters (in which case the LM hash is not stored).
Starting with version 3.7.0, the source code has been moved from SourceForge to GitLab.
See also
Aircrack-ng
Cain and Abel
Crack
DaveGrohl
Hashcat
John the Ripper
L0phtCrack
NMap
RainbowCrack |
https://en.wikipedia.org/wiki/Hamster%20wheel | A hamster wheel or running wheel is an exercise device used primarily by hamsters and other rodents, but also by other cursorial animals when given the opportunity. Most of these devices consist of a runged or ridged wheel held on a stand by a single or pair of stub axles. Hamster wheels allow rodents to run even when their space is confined. The earliest dated use of the term "hamster wheel", located by the Oxford English Dictionary, is in a 1949 newspaper advertisement.
Preferences
Choice tests with Syrian hamsters (Mesocricetus auratus) have shown that they prefer larger wheels; the animals chose a wheel diameter of over , which itself was preferred over .
Hamsters showed no preference between a relatively uniform running surface made of plastic mesh and a surface made of rungs spaced 9 mm apart, although they did prefer the mesh compared to rungs spaced 12 mm apart, most likely because of the wider space between the rungs allowed their legs to slip through. The hamsters neither preferred nor avoided wheels that had small "speed bumps" installed along the running surface to provide environmental enrichment.
Choice tests with mice have also shown a preference for larger wheels (17.5 cm over 13 cm in diameter) and a preference for plastic mesh over rungs and over solid plastic as a running surface. More acrobatic species, such as the canyon mouse (Peromyscus crinitus) and the deer mouse (Peromyscus maniculatus) can develop preferences for wheels that force the animals to jump, such as square wheels or wheels with hurdles along the running surface.
Use by animals
Like other rodents, hamsters are highly motivated to run on wheels; it is not uncommon to record distances of being run in one night. Other 24-h records include for rats, for wild mice, for lemmings, for laboratory mice, and for gerbils. Hypotheses to explain such high levels of running in wheels include a need for activity, substitute for exploration, and stereotypic behaviour. However, free w |
https://en.wikipedia.org/wiki/Central%20pattern%20generator | Central pattern generators (CPGs) are self-organizing biological neural circuits that produce rhythmic outputs in the absence of rhythmic input. They are the source of the tightly-coupled patterns of neural activity that drive rhythmic and stereotyped motor behaviors like walking, swimming, breathing, or chewing. The ability to function without input from higher brain areas still requires modulatory inputs, and their outputs are not fixed. Flexibility in response to sensory input is a fundamental quality of CPG-driven behavior. To be classified as a rhythmic generator, a CPG requires:
"two or more processes that interact such that each process sequentially increases and decreases, and
that, as a result of this interaction, the system repeatedly returns to its starting condition."
CPGs have been found in invertebrates, and practically all vertebrate species investigated, including humans.
General anatomy and physiology
Intrinsic properties of CPG neurons
CPG neurons can have different intrinsic membrane properties (see schematic). Some neurons fire bursts of action potentials, either endogenously or in the presence of neuromodulatory substances. Other neurons are bistable and generate plateau potentials that can be triggered by a depolarizing current pulse, and terminated by a hyperpolarizing current pulse. Many CPG neurons fire after being released from inhibition (postinhibitory rebound). Another common feature of CPG neurons is a decrease in the frequency of firing during a constant depolarization (spike frequency adaptation).
Mechanisms of rhythm generation
Rhythm generation in CPG networks depends on the intrinsic properties of CPG neurons and their synaptic connections. There are two general mechanisms for rhythm generation: pacemaker/follower and reciprocal inhibition (see schematic).
In a network driven by a pacemaker, one or more neurons act as a core oscillator (pacemaker) that drives other, non-bursting neurons (follower) into a rhythmic patter |
https://en.wikipedia.org/wiki/List%20of%20numerical-analysis%20software | Listed here are notable end-user computer applications intended for use with numerical or data analysis:
Numerical-software packages
General-purpose computer algebra systems
Interface-oriented
Language-oriented
Historically significant
Expensive Desk Calculator written for the TX-0 and PDP-1 in the late 1950s or early 1960s.
S is an (array-based) programming language with strong numerical support. R is an implementation of the S language.
See also |
https://en.wikipedia.org/wiki/Festoon | A festoon (from French feston, Italian festone, from a Late Latin festo, originally a festal garland, Latin festum, feast) is a wreath or garland hanging from two points, and in architecture typically a carved ornament depicting conventional arrangement of flowers, foliage or fruit bound together and suspended by ribbons. The motif is sometimes known as a swag when depicting fabric or linen.
In modern English the verb forms, especially "festooned with", are often used very loosely or figuratively to mean having any type of fancy decoration or covering.
Origins and design
Its origin is probably due to the representation in stone of the garlands of natural flowers, etc., which were hung up over an entrance doorway on fête days, or suspended around an altar.
The design was largely employed both by the Ancient Greeks and Romans and formed the principal decoration of altars, friezes and panels. The ends of the ribbons are sometimes formed into bows or twisted curves; when in addition a group of foliage or flowers is suspended, it is called a drop or margent.
The motif was later used in Neoclassical architecture and decorative arts, especially ceramics and the work of silversmiths. Variations on the exact design are plentiful; for example, the ribbons can be suspended either from a decorated knot, or held in the mouths of lions, or suspended across the tops of bucrania as in the Temple of Vesta at Tivoli.
Gallery
See also
Tinsel
Ornament
Classical architecture
Garland bearers
Notes |
https://en.wikipedia.org/wiki/Carnage%20Heart | is a video game for the PlayStation, developed by Artdink. Its gameplay is a mecha-based, turn-based strategy game, where the player takes the role of a commander in a war fought by robots. The robots, called Overkill Engines (OKEs), cannot be directly controlled in battle; they must be programmed beforehand to behave in a certain way under certain conditions using a flow diagram system.
Gameplay
The game features a fairly complex negotiation system that allows the player to purchase, research, or upgrade new equipment and parts. The OKEs themselves can be upgraded as well through this system, allowing for extended use of the same model for as long as possible. The various companies involved in the negotiation process can also provide valuable information about the purchases of the enemy, allowing the player to better plan for the next advance in enemy technology.
To aid the player in learning the gameplay, Carnage Heart was packaged with an unusually large amount of materials for a console game of the time: in addition to the game disc and above-average length manual, the jewel case contained a 58-page strategy guide and a tutorial disc with a 30-minute, fully voice-guided overview of most aspects of the game.
OKE production
The main focus of the game is in the design and programming of the OKEs. The OKEs will only be ready to produce once they have a complete hardware and software profile. Both of these profiles are stored in the form of a "card" that can be named as the player likes. It is possible for there to be a total of 28 cards, but in reality the player may use only 25, as there are three pre-made cards that can not be deleted.
Before a software profile can be created for a card, there must be a hardware profile. The first choice a player must make in the hardware creation process is that of a body type and style. There are four styles of OKE bodies and three designs in each style to choose from. These styles include a two-legged type, a tank type, a m |
https://en.wikipedia.org/wiki/Taeniasis | Taeniasis is an infection within the intestines by adult tapeworms belonging to the genus Taenia. There are generally no or only mild symptoms. Symptoms may occasionally include weight loss or abdominal pain. Segments of tapeworm may be seen in the stool. Complications of pork tapeworm may include cysticercosis.
Types of Taenia that cause infections in humans include Taenia solium (pork tapeworm), Taenia saginata (beef tapeworm), and Taenia asiatica (Asian tapeworm). Taenia saginata is due to eating contaminated undercooked beef while Taenia solium and Taenia asiatica is from contaminated undercooked pork. Diagnosis is by examination of stool samples.
Prevention is by properly cooking meat. Treatment is generally with praziquantel, though niclosamide may also be used. Together with cysticercosis, infections affect about 50 million people globally. The disease is most common in the developing world. In the United States less than 1,000 cases occur a year.
Signs and symptoms
Taeniasis generally has few or no symptoms. It takes about 8 weeks from infection for adult worms to form and can last for years without treatment.
Infection may be suspected when a portion of the worm is passed in the stool. It is not generally fatal.
Pork tapeworm
Infection in the intestines by the adult T. solium worms is normally asymptomatic. Heavy infection can result in anaemia and indigestion.
A complication, known as cysticercosis, may occur if the eggs of the pork tapeworm are eaten. This typically occurs from vegetables or water contaminated by feces from someone with pork tapeworm taeniasis. The eggs enter the intestine where they develop into larvae which then enter the bloodstream and invade host tissues. This is the most frequent and severe disease caused by any tapeworm. It can lead to headaches, dizziness, seizures, dementia, hypertension, lesions in the brain, blindness, tumor-like growths, and low eosinophil levels. It is a cause of major neurological problems, such as |
https://en.wikipedia.org/wiki/Drell%E2%80%93Yan%20process | The Drell–Yan process occurs in high energy hadron–hadron scattering. It takes place when a quark of one hadron and an antiquark of another hadron annihilate, creating a virtual photon or Z boson which then decays into a pair of oppositely-charged leptons. Importantly, the energy of the colliding quark-antiquark pair can be almost entirely transformed into the mass of new particles. This process was first suggested by Sidney Drell and Tung-Mow Yan in 1970 to describe the production of lepton–antilepton pairs in high-energy hadron collisions. Experimentally, this process was first observed by J.H. Christenson et al. in proton–uranium collisions at the Alternating Gradient Synchrotron.
Overview
The Drell–Yan process is studied both in fixed-target and collider experiments. It provides valuable information about the parton distribution functions (PDFs) which describe the way the momentum of an incoming high-energy nucleon is partitioned among its constituent partons. These PDFs are basic ingredients for calculating essentially all processes at hadron colliders. Although PDFs should be derivable in principle, current ignorance of some aspects of the strong force prevents this. Instead, the forms of the PDFs are deduced from experimental data.
Drell–Yan process and deep inelastic scattering
PDFs are determined using the world data from deep inelastic scattering, Drell–Yan process etc.
The Drell–Yan process is closely related to the deep inelastic scattering; the Feynman diagram
of the Drell–Yan process is obtained if the Feynman diagram of deep inelastic scattering is rotated by 90°.
A time-like virtual photon or Z boson is produced in s-channel in the Drell–Yan process
while a space-like virtual photon or Z boson is produced in t-channel in the deep inelastic scattering.
Sensitivity to light sea quark flavor asymmetry in the proton
It had been naively believed that the quark sea in the proton was formed by quantum chromodynamics (QCD) processes that did not di |
https://en.wikipedia.org/wiki/The%20Parrot%27s%20Theorem | The Parrot's Theorem is a French novel written by Denis Guedj and published in 1998. An English translation was published in 2000.
Plot summary
The plot revolves around a household in Paris: Mr Ruche, an elderly wheelchair-using bookseller, his employee and housemate Perrette, and Perrette's three children – teenage twins and young Max, who is deaf. Max liberates a talking parrot at the market and Mr Ruche receives a consignment of mathematical books from an old friend, who has lived in Brazil for decades without any contact between the two.
The household sets up its own exploration of mathematics in order to crack the code of the last messages from Mr Ruche's old friend, now apparently murdered. Mathematical topics covered in the book include primes and factors; irrational and amicable numbers; the discoveries of Pythagoras, Archimedes and Euclid; and the problems of squaring the circle and doubling the cube.
The mathematics is real mathematics, woven into an historical sequence as a series of intriguing problems, bringing their own stories with them.
See also
Forrest Library
Numbers: The Universal Language |
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