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https://en.wikipedia.org/wiki/Dino%20Cube | The Dino Cube is a cubic twisty puzzle in the style of the Rubik's Cube. It was invented in 1985 by Robert Webb, though it was not mass-produced until ten years later. It has a total of 12 external movable pieces to rearrange, compared to 20 movable pieces on the Rubik's Cube.
History
Robert Webb designed and made the first prototype of what would become the Dino Cube in 1985; his original prototype was made entirely out of paper. Since then the puzzle was reinvented twice, but full mass production of the puzzle did not start until 1995. The first mass-produced version had pictures of dinosaurs depicted on each piece, which led to the adoption of the puzzle's current name of Dino Cube. It is not known what the puzzle had been called before this dinosaur version was introduced. The later versions, however, adopted the practice of using standard single-colour stickers, in common with most other twisty puzzles.
Overview
The Dino Cube is a twisty puzzle in the shape of a cube. It consists of 12 movable pieces, all of which are located on the edges of the cube.
The puzzle can be thought of as twisting around its corners: each move changes the position of three edge pieces adjacent to the same corner, by rotating them around that corner. There are in fact eight more "hidden" pieces inside the puzzle, which are located at the corners and are fixed to the puzzle's core; these pieces only become visible in the middle of a move.
The vast majority of mass-produced Dino Cubes have the standard six-colour scheme, with one colour on each face of the cube in the solved state. This is in common with most other cubic twisty puzzles, including the Rubik's Cube. However, a few versions with other colour schemes also exist, including one with four colours (where each colour is centred around one corner of the cube in the solved state), and one with just two colours (where each colour present on half of the puzzle).
The purpose of the puzzle is to scramble the colours and then re |
https://en.wikipedia.org/wiki/Spallation | Spallation is a process in which fragments of material (spall) are ejected from a body due to impact or stress. In the context of impact mechanics it describes ejection of material from a target during impact by a projectile. In planetary physics, spallation describes meteoritic impacts on a planetary surface and the effects of stellar winds and cosmic rays on planetary atmospheres and surfaces. In the context of mining or geology, spallation can refer to pieces of rock breaking off a rock face due to the internal stresses in the rock; it commonly occurs on mine shaft walls. In the context of anthropology, spallation is a process used to make stone tools such as arrowheads by knapping. In nuclear physics, spallation is the process in which a heavy nucleus emits numerous nucleons as a result of being hit by a high-energy particle, thus greatly reducing its atomic weight. In industrial processes and bioprocessing the loss of tubing material due to the repeated flexing of the tubing within a peristaltic pump is termed spallation.
In solid mechanics
Spallation can occur when a tensile stress wave propagates through a material and can be observed in flat plate impact tests. It is caused by an internal cavitation due to stresses, which are generated by the interaction of stress waves, exceeding the local tensile strength of materials. A fragment or multiple fragments will be created on the free end of the plate. This fragment known as "spall" acts as a secondary projectile with velocities that can be as high as one third of the stress wave speed on the material. This type of failure is typically an effect of high explosive squash head (HESH) charges.
Laser spallation
Laser induced spallation is a recent experimental technique developed to understand the adhesion of thin films with substrates. A high energy pulsed laser (typically Nd:YAG) is used to create a compressive stress pulse in the substrate wherein it propagates and reflects as a tensile wave at the free boundar |
https://en.wikipedia.org/wiki/50S%20ribosomal%20protein%20L25 | 50S ribosomal protein L25 is a protein that in Escherichia coli is encoded by the gene.
Function
This ribosomal protein is a component of the 50S subunit. The protein binds 5S rRNA to form a stable complex. In turn 5S rRNA binds specifically to three proteins, L25, L18 and L5, forming a separate domain of the bacterial ribosome. Protein L25 of E. coli is not essential for survival of the cells.
Interactions
Ribosomal protein L25 has been shown to interact with:
50S ribosomal protein L16
5S ribosomal RNA |
https://en.wikipedia.org/wiki/Darwinian%20literary%20studies | Darwinian literary studies (also known as literary Darwinism) is a branch of literary criticism that studies literature in the context of evolution by means of natural selection, including gene-culture coevolution. It represents an emerging trend of neo-Darwinian thought in intellectual disciplines beyond those traditionally considered as evolutionary biology: evolutionary psychology, evolutionary anthropology, behavioral ecology, evolutionary developmental psychology, cognitive psychology, affective neuroscience, behavioural genetics, evolutionary epistemology, and other such disciplines.
History and scope
Interest in the relationship between Darwinism and the study of literature began in the nineteenth century, for example, among Italian literary critics. For example, Ugo Angelo Canello argued that literature was the history of the human psyche, and as such, played a part in the struggle for natural selection, while Francesco de Sanctis argued that Emile Zola "brought the concepts of natural selection, struggle for existence, adaptation and environment to bear in his novels".
Modern Darwinian literary studies arose in part as a result of its proponents' dissatisfaction with the poststructuralist and postmodernist philosophies that had come to dominate literary study during the 1970s and 1980s. In particular, the Darwinists took issue with the argument that discourse constructs reality. The Darwinists argue that biologically grounded dispositions constrain and inform discourse. This argument runs counter to what evolutionary psychologists assert is the central idea in the "Standard Social Science Model": that culture wholly constitutes human values and behaviors.
Literary Darwinists use concepts from evolutionary biology and the evolutionary human sciences to formulate principles of literary theory and interpret literary texts. They investigate interactions between human nature and the forms of cultural imagination, including literature and its oral antecedent |
https://en.wikipedia.org/wiki/The%20Billion-Dollar%20Molecule | The Billion-Dollar Molecule is a book by journalist Barry Werth about the founding and early research efforts of the American biotechnology company Vertex Pharmaceuticals, which was founded in 1989 by Joshua Boger and was among the first biotechnology companies to adopt an explicit strategy of rational drug design as opposed to techniques based on combinatorial chemistry.
This book is notable as an inside look at a biotechnology company, and the stresses and marketing pressures on funding research into drug design. This book is a mixture of finance and technology.
In February, 2014, Barry Werth published a follow-on book, The Antidote, that looks at Vertex 20 years later after his original effort. |
https://en.wikipedia.org/wiki/Tidal%20locking | Tidal locking between a pair of co-orbiting astronomical bodies occurs when one of the objects reaches a state where there is no longer any net change in its rotation rate over the course of a complete orbit. In the case where a tidally locked body possesses synchronous rotation, the object takes just as long to rotate around its own axis as it does to revolve around its partner. For example, the same side of the Moon always faces the Earth, although there is some variability because the Moon's orbit is not perfectly circular. Usually, only the satellite is tidally locked to the larger body. However, if both the difference in mass between the two bodies and the distance between them are relatively small, each may be tidally locked to the other; this is the case for Pluto and Charon, as well as for Eris and Dysnomia. Alternative names for the tidal locking process are gravitational locking, captured rotation, and spin–orbit locking.
The effect arises between two bodies when their gravitational interaction slows a body's rotation until it becomes tidally locked. Over many millions of years, the interaction forces changes to their orbits and rotation rates as a result of energy exchange and heat dissipation. When one of the bodies reaches a state where there is no longer any net change in its rotation rate over the course of a complete orbit, it is said to be tidally locked. The object tends to stay in this state because leaving it would require adding energy back into the system. The object's orbit may migrate over time so as to undo the tidal lock, for example, if a giant planet perturbs the object.
Not every case of tidal locking involves synchronous rotation. With Mercury, for example, this tidally locked planet completes three rotations for every two revolutions around the Sun, a 3:2 spin–orbit resonance. In the special case where an orbit is nearly circular and the body's rotation axis is not significantly tilted, such as the Moon, tidal locking results in th |
https://en.wikipedia.org/wiki/Network%20convergence | Network convergence refers to the provision of telephone, video and data communication services within a single network. In other words, one company provides services for all forms of communication. Network convergence is primarily driven by development of technology and demand. Users are able to access a wider range of services, choose among more service providers. On the other hand, convergence allows service providers to adopt new business models, offer innovative services, and enter new markets.
Introduction
One dictionary definition of "convergence" provides a starting point for the analysis: "the act of converging and esp. moving toward union or uniformity." The new regulatory framework that was shaped by the 1996 act eliminated the entry barrier for companies to expand their business into new markets. Local exchange carriers are allowed to start a business in the long-distance market and even video and broadband market. On the other hand, because cable TV and video services are regulated as "information services", cable companies are allowed entering the telecommunication market without applying for a license and exempted from heavy regulation. Two-way communication has been limited to voice and text by the limited availability of bandwidth; broadcast media have been restricted by their one-way character and by the availability of spectrum. Nowadays technology development, fierce competition, and deregulation have transformed several distinct communications service markets into a converged market. In the telecommunications world, convergence has come to mean a moving towards the use of one medium as opposed to manipulation of all forms of information including voice, data, and video across all types of network instead of carrying information separately within distinct networks. In the convergent network, different forms of information can be re-engineered to provide better, more flexible service to the user. For example, telephone networks can transmit data |
https://en.wikipedia.org/wiki/Silverman%E2%80%93Toeplitz%20theorem | In mathematics, the Silverman–Toeplitz theorem, first proved by Otto Toeplitz, is a result in summability theory characterizing matrix summability methods that are regular. A regular matrix summability method is a matrix transformation of a convergent sequence which preserves the limit.
An infinite matrix with complex-valued entries defines a regular summability method if and only if it satisfies all of the following properties:
An example is Cesaro summation, a matrix summability method with |
https://en.wikipedia.org/wiki/Lunar%20Receiving%20Laboratory | The Lunar Receiving Laboratory (LRL) was a facility at NASA's Lyndon B. Johnson Space Center (Building 37) that was constructed to quarantine astronauts and material brought back from the Moon during the Apollo program to reduce the risk of back-contamination. After recovery at sea, crews from Apollo 11, Apollo 12, and Apollo 14 walked from their helicopter to the Mobile Quarantine Facility on the deck of an aircraft carrier and were brought to the LRL for quarantine. Samples of rock and regolith that the astronauts collected and brought back were flown directly to the LRL and initially analyzed in glovebox vacuum chambers.
The quarantine requirement was dropped for Apollo 15 and later missions. The LRL was used for study, distribution, and safe storage of the lunar samples. Between 1969 and 1972, six Apollo space flight missions brought back 382 kilograms (842 pounds) of lunar rocks, core samples, pebbles, sand, and dust from the lunar surface—in all, 2,200 samples from six exploration sites. Other lunar samples were returned to Earth by three automated Soviet spacecraft, Luna 16 in 1970, Luna 20 in 1972, and Luna 24 in 1976, which returned samples totaling 300 grams (about 3/4 pound).
In 1976, some of the samples were moved to Brooks Air Force Base in San Antonio, Texas, for second-site storage. In 1979, a Lunar Sample Laboratory Facility was built to serve as the chief repository for the Apollo samples: permanent storage in a physically secure and non-contaminating environment. The facility includes vaults for the samples and records, and laboratories for sample preparation and study. The Lunar Receiving Laboratory building was later occupied by NASA's Life Sciences division, contained biomedical and environment labs, and was used for experiments involving human adaptation to microgravity.
In September 2019, NASA announced that the Lunar Receiving Laboratory had not been used for two years and would be demolished.
See also
Moon rock
Lunar Sample Laborator |
https://en.wikipedia.org/wiki/TYPSET%20and%20RUNOFF | TYPSET is an early document editor that was used with the 1964-released RUNOFF program, one of the earliest text formatting programs to see significant use.
Of two earlier print/formatting programs DITTO and TJ-2, only the latter had, and introduced, text justification; RUNOFF also added pagination.
The name RUNOFF, and similar names led to other formatting program implementations. By 1982 Runoff largely became associated with Digital Equipment Corporation and Unix computers. DEC used the terms VAX DSR and DSR to refer to VAX DIGITAL Standard Runoff.
History
CTSS
The original RUNOFF type-setting program for CTSS was written by Jerome H. Saltzer circa 1964. Bob Morris and Doug McIlroy translated that from MAD to BCPL. Morris and McIlroy then moved the BCPL version to Multics when the IBM 7094 on which CTSS ran was being shut down.
Multics
Documentation for the Multics version of RUNOFF described it as "types out text segments in manuscript form."
Other versions and implementations
A later version of runoff for Multics was written in PL/I by Dennis Capps, in 1974. This runoff code was the ancestor of roff that was written for the fledgling Unix in assembly language by Ken Thompson.
Other versions of Runoff were developed for various computer systems including Digital Equipment Corporation's PDP-11 minicomputer systems running RT-11, RSTS/E, RSX on Digital's PDP-10 and for OpenVMS on VAX minicomputers, as well as UNIVAC Series 90 mainframes using the EDT text editor under the VS/9 operating system. These different releases of Runoff typically had little in common except the convention of indicating a command to Runoff by beginning the line with a period.
The origin of IBM's SCRIPT (markup) software began in 1968 when "IBM contracted Stuart Madnick of MIT to write a simple document preparation ..." to run on CP/67. He modeled it on MIT's CTSS RUNOFF.
Background
RUNOFF was written in 1964 for the CTSS operating system by Jerome H. Saltzer in MAD and FAP.
It |
https://en.wikipedia.org/wiki/Roma%20%28personification%29 | In ancient Roman religion, Roma was a female deity who personified the city of Rome and more broadly, the Roman state. She was created and promoted to represent and propagate certain of Rome's ideas about itself, and to justify its rule. She was portrayed on coins, sculptures, architectural designs, and at official games and festivals. Images of Roma had elements in common with other goddesses, such as Rome's Minerva, her Greek equivalent Athena and various manifestations of Greek Tyche, who protected Greek city-states; among these, Roma stands dominant, over piled weapons that represent her conquests, and promising protection to the obedient. Her "Amazonian" iconography shows her "manly virtue" (virtus) as fierce mother of a warrior race, augmenting rather than replacing local goddesses. On some coinage of the Roman Imperial era, she is shown as a serene advisor, partner and protector of ruling emperors. In Rome, the Emperor Hadrian built and dedicated a gigantic temple to her as Roma Aeterna ("Eternal Rome"), and to Venus Felix, ("Venus the Bringer of Good Fortune"), emphasising the sacred, universal and eternal nature of the empire.
Roma's official cult served to advance the propagandist message of Imperial Rome. In Roman art and coinage, she is usually depicted in military form, with helmet and weapons. In Rome's eastern provinces, she was often shown with mural crown or cornucopia, or both. Her image is rarely found in a commonplace or domestic context. Roma was probably favoured by Rome's high-status Imperial representatives abroad, rather than the Roman populace at large. She was depicted on silver cups, arches, and sculptures, including the base of the column of Antoninus Pius. She survived into the Christian period as a personification of the Roman state. Her depiction seated with a shield and spear later influenced that of Britannia, personification of Britain.
Republican era
Identity and iconography
A helmeted figure on Roman coins of 280–276 and 265– |
https://en.wikipedia.org/wiki/Cool%27n%27Quiet | AMD Cool'n'Quiet is a CPU dynamic frequency scaling and power saving technology introduced by AMD with its Athlon XP processor line. It works by reducing the processor's clock rate and voltage when the processor is idle. The aim of this technology is to reduce overall power consumption and lower heat generation, allowing for slower (thus quieter) cooling fan operation. The objectives of cooler and quieter result in the name Cool'n'Quiet. The technology is similar to Intel's SpeedStep and AMD's own PowerNow!, which were developed with the aim of increasing laptop battery life by reducing power consumption.
Due to their different usage, Cool'n'Quiet refers to desktop and server chips, while PowerNow! is used for mobile chips; the technologies are similar but not identical. This technology was also introduced on "e-stepping" Opterons, however it is called Optimized Power Management, which is essentially a re-tooled Cool'n'Quiet scheme designed to work with registered memory.
Cool'n'Quiet is fully supported in the Linux kernel from version 2.6.18 onward (using the powernow-k8 driver) and FreeBSD from 6.0-CURRENT onward.
Implementation
In-order to take advantage of Cool'n'Quiet Technology in Microsoft's Operating Systems:
Cool'n'Quiet should be Enabled in system BIOS
In Windows XP and 2000: Operating Systems "Minimal Power Management" profile must be active in "Power Schemes". A PPM driver was also released by AMD that facilitates this.
In Windows Vista and 7: "Minimum processor state" found in "Processor Power Management" of "Advanced Power Settings" should be lower than "100%".
Also In Windows Vista and 7 the "Power Saver" power profile allows much lower power state (frequency and voltage) than in the "High Performance" power state.
Unlike Windows XP, Windows Vista only supports Cool'n'Quiet on motherboards that support ACPI 2.0 or later.
With earlier versions of Windows, processor drivers along with Cool'n'Quiet software also need to be installed. The latest v |
https://en.wikipedia.org/wiki/Merodiploid | A merodiploid is a partially diploid bacterium, which has its own chromosome complement and a chromosome fragment introduced by conjugation, transformation or transduction. It can also be defined as an essentially haploid organism that carries a second copy of a part of its genome. The term is derived from the Greek, meros = part, and was originally used to describe both unstable partial diploidy, such as that which occurs briefly in recipients after mating with an Hfr strain (1), and the stable state, exemplified by F-prime strains (see Hfr'S And F-Primes). Over time the usage has tended to confine the term to descriptions of stable genetic states. Merodiploidy refers to the partial duplication of chromosomes in a haploid organism. |
https://en.wikipedia.org/wiki/GitKraken | GitKraken (formerly Axosoft) is a software company based in Scottsdale, Arizona. Founded in 2000, the company was purchased in 2020 by Resurgens Technology Partners, and changed its name from Axosoft to GitKraken in 2021.
GitKraken
The company's eponymous product GitKraken is a suite of developer tools. The GitKraken Suite includes three tools: GitKraken Git GUI, a Git client available on Mac, Windows, and Linux, GitKraken Issue Boards, Kanban style boards, and GitKraken Timelines, an online timeline maker.
Axosoft
The Axosoft (formerly OnTime) product is a proprietary project management and bug tracking system developed by GitKraken.
The system is available as hosted or on-premises software. The software allows project managers and developers to see each task, requirement, defect and incident in the system on individual filing cards through the Scrum planning board. Axosoft operates as a web application and can integrate with Microsoft Visual Studio and TortoiseSVN. |
https://en.wikipedia.org/wiki/Pancreatitis | Pancreatitis is a condition characterized by inflammation of the pancreas. The pancreas is a large organ behind the stomach that produces digestive enzymes and a number of hormones. There are two main types: acute pancreatitis, and chronic pancreatitis.
Signs and symptoms of pancreatitis include pain in the upper abdomen, nausea and vomiting. The pain often goes into the back and is usually severe. In acute pancreatitis, a fever may occur; symptoms typically resolve in a few days. In chronic pancreatitis weight loss, fatty stool, and diarrhea may occur. Complications may include infection, bleeding, diabetes mellitus, or problems with other organs.
The two most common causes of acute pancreatitis are a gallstone blocking the common bile duct after the pancreatic duct has joined; and heavy alcohol use. Other causes include direct trauma, certain medications, infections such as mumps, and tumors. Chronic pancreatitis may develop as a result of acute pancreatitis. It is most commonly due to many years of heavy alcohol use.
Other causes include high levels of blood fats, high blood calcium, some medications, and certain genetic disorders, such as cystic fibrosis, among others. Smoking increases the risk of both acute and chronic pancreatitis. Diagnosis of acute pancreatitis is based on a threefold increase in the blood of either amylase or lipase. In chronic pancreatitis, these tests may be normal. Medical imaging such as ultrasound and CT scan may also be useful.
Acute pancreatitis is usually treated with intravenous fluids, pain medication, and sometimes antibiotics. Typically eating and drinking are disallowed, and a nasogastric tube is placed in the stomach. A procedure known as an endoscopic retrograde cholangiopancreatography (ERCP) may be done to examine the distal common bile duct and remove a gallstone if present. In those with gallstones the gallbladder is often also removed. In chronic pancreatitis, in addition to the above, temporary feeding through a |
https://en.wikipedia.org/wiki/Non-analytic%20smooth%20function | In mathematics, smooth functions (also called infinitely differentiable functions) and analytic functions are two very important types of functions. One can easily prove that any analytic function of a real argument is smooth. The converse is not true, as demonstrated with the counterexample below.
One of the most important applications of smooth functions with compact support is the construction of so-called mollifiers, which are important in theories of generalized functions, such as Laurent Schwartz's theory of distributions.
The existence of smooth but non-analytic functions represents one of the main differences between differential geometry and analytic geometry. In terms of sheaf theory, this difference can be stated as follows: the sheaf of differentiable functions on a differentiable manifold is fine, in contrast with the analytic case.
The functions below are generally used to build up partitions of unity on differentiable manifolds.
An example function
Definition of the function
Consider the function
defined for every real number x.
The function is smooth
The function f has continuous derivatives of all orders at every point x of the real line. The formula for these derivatives is
where pn(x) is a polynomial of degree n − 1 given recursively by p1(x) = 1 and
for any positive integer n. From this formula, it is not completely clear that the derivatives are continuous at 0; this follows from the one-sided limit
for any nonnegative integer m.
By the power series representation of the exponential function, we have for every natural number (including zero)
because all the positive terms for are added. Therefore, dividing this inequality by and taking the limit from above,
We now prove the formula for the nth derivative of f by mathematical induction. Using the chain rule, the reciprocal rule, and the fact that the derivative of the exponential function is again the exponential function, we see that the formula is correct for the first deri |
https://en.wikipedia.org/wiki/Photosensitivity | Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity. The photosensitive ganglion cells in the mammalian eye are a separate class of light-detecting cells from the photoreceptor cells that function in vision.
Skin reactions
Human medicine
Sensitivity of the skin to a light source can take various forms. People with particular skin types are more sensitive to sunburn. Particular medications make the skin more sensitive to sunlight; these include most of the tetracycline antibiotics, heart drugs amiodarone, and sulfonamides.
Some dietary supplements, such as St. John's Wort, include photosensitivity as a possible side effect.
Particular conditions lead to increased light sensitivity. Patients with systemic lupus erythematosus experience skin symptoms after sunlight exposure; some types of porphyria are aggravated by sunlight. A rare hereditary condition xeroderma pigmentosum (a defect in DNA repair) is thought to increase the risk of UV-light-exposure-related cancer by increasing photosensitivity.
Veterinary medicine
Photosensitivity occurs in multiple species including sheep, bovine, and horses. They are classified as primary if an ingested plant contains a photosensitive substance, like hypericin in St John's wort poisoning and ingestion of biserrula (Biserrula pelecinus) in sheep, or buckwheat plants (green or dried) in horses.
In hepatogenous photosensitization, the photosensitzing substance is phylloerythrin, a normal end-product of chlorophyll metabolism. It accumulates in the body because of liver damage, reacts with UV light on the skin, and leads to free radical formation. These free radicals damage the skin, leading to ulceration, necrosis, and sloughing. Non-pigmented skin is most commonly affected.
See also
Digital camera ISO
Bergaptene
Heliotropism
|
https://en.wikipedia.org/wiki/T1%20holin%20family | The Phage T1 Holin (T1 Holin) Family (TC# 1.E.37) is represented in enterobacterial phages T1, RTP and F20, Klebsiella phage KP36, and Escherichia phage ADB-2. All of these possess a putative holin that share a high level of identity. Additionally, Gp9 of E. coli phage phiE49 is similar in sequence. These proteins are short, 55 to 71 amino acyl residues (aas) in length, and exhibit a single transmembrane segment (TMS). A representative list of proteins belonging to the T1 Holin family can be found in the Transporter Classification Database.
See also
Holin
Lysin
Transporter Classification Database
Further reading
.
.
.
. |
https://en.wikipedia.org/wiki/HackerRank | HackerRank is a technology company that focuses on competitive programming challenges for both consumers and businesses. Developers compete by writing programs according to provided specifications. HackerRank's programming challenges can be solved in a variety of programming languages (including Java, C++, PHP, Python, SQL, and JavaScript) and span multiple computer science domains.
HackerRank categorizes most of their programming challenges into a number of core computer science domains, including database management, mathematics, and artificial intelligence.
When a programmer submits a solution to a programming challenge, their submission is scored on the accuracy of their output. Programmers are then ranked globally on the HackerRank leaderboard and earn badges based on their accomplishments, which is intended to drive competition among users. In addition to individual coding challenges, HackerRank also hosts contests (often referred to by HackerRank as "CodeSprints") where users compete on the same programming challenges during a set period of time and are then ranked at the conclusion of the event. HackerRank is part of the growing gamification trend within competitive computer programming. The consumer side of their website is free for coders to use.
History
HackerRank was founded as InterviewStreet Inc. by two NIT Trichy alumni, Vivek Ravisankar and Hari Karunanidhi. HackerRank is a Y Combinator-backed company, and was the first Indian company accepted into Y Combinator. They also participated in TechCrunch Disrupt in 2012, and currently have venture capital backing from Khosla Ventures and Battery Ventures.
Funding
In July 2015, HackerRank received $7.5 million funding from Japanese firm Recruit Holdings’ HR technology fund. On February 13, 2018 HackerRank announced it had raised $30 million in Series C funding, led by JMI Equity.
Acquisition
In December 2019, HackerRank acquired Mimir, a cloud-based service that provides tools for teaching computer |
https://en.wikipedia.org/wiki/Dougall%27s%20formula | Dougall's formula may refer to one of two formulas for hypergeometric series, both named after John Dougall:
Dougall's formula for the sum of a 7F6 hypergeometric series
Dougall's formula for the sum of a bilateral hypergeometric series
Hypergeometric functions |
https://en.wikipedia.org/wiki/Necklace%20%28combinatorics%29 | In combinatorics, a k-ary necklace of length n is an equivalence class of n-character strings over an alphabet of size k, taking all rotations as equivalent. It represents a structure with n circularly connected beads which have k available colors.
A k-ary bracelet, also referred to as a turnover (or free) necklace, is a necklace such that strings may also be equivalent under reflection. That is, given two strings, if each is the reverse of the other, they belong to the same equivalence class. For this reason, a necklace might also be called a fixed necklace to distinguish it from a turnover necklace.
Formally, one may represent a necklace as an orbit of the cyclic group acting on n-character strings over an alphabet of size k, and a bracelet as an orbit of the dihedral group. One can count these orbits, and thus necklaces and bracelets, using Pólya's enumeration theorem.
Equivalence classes
Number of necklaces
There are
different k-ary necklaces of length n, where is Euler's totient function. This follows directly from Pólya's enumeration theorem applied to the action of the cyclic group acting on the set of all functions .
There are also
different necklaces of length n with exactly k different colored beads, where are the Stirling number of the second kind. (The variable k is overloaded and it is unclear whether k refers to the alphabet size or to the number of distinct elements in the necklace.)
and are related via the Binomial coefficients:
and
Number of bracelets
There are a total of
different k-ary bracelets of length n, where Nk(n) is the number of k-ary necklaces of length n. This follows from Pólya's method applied to the action of the dihedral group .
Case of distinct beads
For a given set of n beads, all distinct, the number of distinct necklaces made from these beads, counting rotated necklaces as the same, is = (n − 1)!. This is because the beads can be linearly ordered in n! ways, and the n circular shifts of s |
https://en.wikipedia.org/wiki/Alexander%20Nabutovsky | Alexander Nabutovsky is a leading Canadian mathematician specializing in differential geometry, geometric calculus of variations and quantitative aspects of topology of manifolds. He is a professor at the University of Toronto Department of Mathematics.
Nabutovsky earned a Ph.D. degree from the Weizmann Institute of Science
in 1993; his advisor was Shmuel Kiro.
He was an invited speaker on "Geometry" at International Congress of Mathematicians, 2010 in Hyderabad. |
https://en.wikipedia.org/wiki/Moto%20%28restaurant%29 | Moto was a molecular gastronomy restaurant in the Fulton River District of Chicago, Illinois known for creating "high-tech" dishes which incorporate elements such as carbonated fruit, edible paper, lasers, and liquid nitrogen for freezing food.
Moto was run by executive chef Homaro Cantu until his suicide in 2015. Sister restaurant iNG was located next door and served "flavor tripping cuisine" based on "the miracle berry", which makes sour foods taste sweet.
History
In 2003, restaurateur Joseph De Vito, who had previously opened a burger joint and a classical Italian eatery, was looking to open a new restaurant. He wanted it to be unusual and was considering Asian fusion. Chef Homaro Cantu, then sous chef at Charlie Trotter's, applied for the job, pitching something really different. "This guy comes in with these little glasses, he looks like an accountant," De Vito recalled, "and started talking about levitating food. I walked away saying, 'Wow, that's a lot to take in.'" Cantu persuaded De Vito to let him cook a meal for De Vito and his wife. The seven-course meal, which featured an exploding ravioli and a small table-top box that cooked fish before the guest's eyes, won De Vito over. The name Moto, meaning "idea," "taste," or "desire" in Japanese, was chosen for the new venture.
Nestled among warehouses in Chicago's meatpacking district, Moto opened in January 2004. Initially, guests were confused. People would come in looking for sushi and leave when offered a degustation menu instead, De Vito recalled. Enough people braved the menu, however, and soon the restaurant was discovered by foodies. Cantu soon earned a reputation for shocking guests. For example, one feature was synthetic wine squirted into the glass with a medical syringe. An industrial-sized tank of liquid nitrogen was kept outside the restaurant to make hot food cold and give fishes odd shapes.
In the kitchen, Cantu employed unusual devices such as a centrifuge, a hand-held ion part |
https://en.wikipedia.org/wiki/European%20Information%20Technologies%20Certification | The European Information Technologies Certification (EITC) programme is an international professional ICT knowledge and skills certification standard. It is developed and governed by the EITCI Institute, a non-profit organization based in Brussels that provides certification of individuals' knowledge and skills in narrow, specialized single-subject areas of ICT such as office software, computer-aided project management, online collaboration systems, and raster graphics processing.
See also
EITCA programme
EITCI institute |
https://en.wikipedia.org/wiki/Fibrocartilage%20callus | A fibrocartilage callus is a temporary formation of fibroblasts and chondroblasts which forms at the area of a bone fracture as the bone attempts to heal itself. The cells eventually dissipate and become dormant, lying in the resulting extracellular matrix that is the new bone.
The callus is the first sign of union visible on x-rays, usually 3 weeks after the fracture. Callus formation is slower in adults than in children, and in cortical bones than in cancellous bones.
See also
Bone healing |
https://en.wikipedia.org/wiki/Marcel%20Riesz | Marcel Riesz ( ; 16 November 1886 – 4 September 1969) was a Hungarian mathematician, known for work on summation methods, potential theory, and other parts of analysis, as well as number theory, partial differential equations, and Clifford algebras. He spent most of his career in Lund (Sweden).
Marcel is the younger brother of Frigyes Riesz, who was also an important mathematician and at times they worked together (see F. and M. Riesz theorem).
Biography
Marcel Riesz was born in Győr, Austria-Hungary. He was the younger brother of the mathematician Frigyes Riesz. In 1904, he won the Loránd Eötvös competition. Upon entering the Budapest University, he also studied in Göttingen, and the academic year 1910-11 he spent in Paris. Earlier, in 1908, he attended the
1908 International Congress of Mathematicians in Rome. There he met Gösta Mittag-Leffler, in three years, Mittag-Leffler would offer Riesz to come to Sweden.
Riesz obtained his PhD at Eötvös Loránd University under the supervision of Lipót Fejér. In 1911, he moved to Sweden, where from 1911 to 1925 he taught at Stockholm University.
From 1926 to 1952, he was a professor at Lund University. According to Lars Gårding, Riesz arrived in Lund as a renowned star of mathematics, and for a time his appointment may have seemed like an exile. Indeed, there was no established school of mathematics in Lund at the time. However, Riesz managed to turn the tide and make the academic atmosphere more active.
Retired from the Lund University, he spent 10 years at universities in the United States. As a visiting research professor, he worked in Maryland, Chicago, etc.
After ten years of intense work with little rest, he suffered a breakdown. Riesz returned to Lund in 1962. After a long illness, he died there in 1969.
Riesz was elected a member of the Royal Swedish Academy of Sciences in 1936.
Mathematical work
Classical analysis
The work of Riesz as a student of Fejér in Budapest was devoted to trigonometric series:
|
https://en.wikipedia.org/wiki/Simalto | SIMALTO – SImultaneous Multi-Attribute Trade Off – is a survey based statistical technique used in market research that helps determine how people prioritise and value alternative product and/or service options of the attributes that make up individual products or services.
A particular specific application of the method is in political science. It can be applied to predicting which of the alternative combinations of optional service benefits provided by a local authority, state or national government in their annual budget would meet with the ‘maximum’ approval of a target population.
Survey design
SIMALTO is based on creating a matrix of the options that can combine to form the product or service. Each row of the matrix represents an attribute and the matrix columns are the various options (alternative features, levels of service, benefits) of that particular row attribute. Each option is associated with ‘cost points’ which indicates how much more or less that option costs to deliver than the other options on the matrix. The cost points may reflect the actual price in currency, say, of a consumer or industrial product option, or, more commonly in service applications, the relative costs to the supplier of delivering the different benefit options.
Example SIMALTO Matrix : To improve from 8 hours service response time to 2 hours would ‘cost’ an extra 10 points. This would be twice the cost of improving from 6–10 days wait for spare parts to a 3-5 day wait.
Respondents complete a series of tasks on this matrix. These may include indicating the option on each row he currently perceives he experiences in the product or service he has now and/or his perception of a rival product or service performance. But the main tasks completed on the matrix are the respondents prioritisation of the options within total ‘constrained’ budgets. The respondent is given a total number of ‘cost points’ which he allocates to the options on the matrix to ‘design’ his preferred total sp |
https://en.wikipedia.org/wiki/Sue%20Singer | Sue Singer is a British mathematics educator. She is the former headmistress of Guildford High School, a girls' school in Surrey, the former president of the Girls' Schools Association, and the former president of the Mathematical Association.
Career
Singer married and had children before studying at the university level, and began her university studies in 1971 with a mathematics course at the Open University, in its first class of students. After completing a degree through the Open University, and a Postgraduate Certificate in Education at Garnett College, she became a mathematics teacher at St Paul's Girls' School, and eventually head of mathematics there, before becoming headmistress at Guildford. She retired from Guildford in 2002 and later became a recruitment consultant, leading the schools practice at Saxton Bampfylde.
Association leadership
As president of the Girls' Schools Association, she led calls to replace the General Certificate of Secondary Education examination system by teacher evaluations.
Singer was president of the Mathematical Association for the 2005–2006 term. She is an avid sailor, and her presidential address to the Mathematical Association included mathematical problems associated with sailing as examples of the applicability of mathematics to everyday life, a topic that she felt should be emphasized in mathematical teaching. |
https://en.wikipedia.org/wiki/Ristocetin | Ristocetin is a glycopeptide antibiotic, obtained from Amycolatopsis lurida, previously used to treat staphylococcal infections. It is no longer used clinically because it caused thrombocytopenia and platelet agglutination. It is now used solely to assay those functions in vitro in the diagnosis of conditions such as von Willebrand disease (vWD) and Bernard–Soulier syndrome. Platelet agglutination caused by ristocetin can occur only in the presence of von Willebrand factor multimers, so if ristocetin is added to blood lacking the factor (or its receptor—see below), the platelets will not clump.
Through an unknown mechanism, the antibiotic ristocetin causes von Willebrand factor to bind the platelet receptor glycoprotein Ib (GpIb), so when ristocetin is added to normal blood, it causes agglutination.
In some types of vWD (types 2B and platelet-type), even very small amounts of ristocetin cause platelet aggregation when the patient's platelet-rich plasma is used. This paradox is explained by these types having gain-of-function mutations which cause the vWD high molecular-weight multimers to bind more tightly to their receptors on platelets (the alpha chains of glycoprotein Ib (GPIb) receptors). In the case of type 2B vWD, the gain-of-function mutation involves von Willebrand's factor (VWF gene), and in platelet-type vWD, the receptor is the object of the mutation (GPIb). This increased binding causes vWD because the high-molecular weight multimers are removed from circulation in plasma since they remain attached to the patient's platelets. Thus, if the patient's platelet-poor plasma is used, the ristocetin cofactor assay will not agglutinate standardized platelets (i.e., pooled platelets from normal donors that are fixed in formalin), similar to the other types of vWD.
In all forms of the ristocetin assay, the platelets are fixed in formalin prior to the assay to prevent von Willebrand's factor stored in platelet granules from being released and participating |
https://en.wikipedia.org/wiki/Ferula%20communis | Ferula communis, the giant fennel, is a species of flowering plant in the carrot family Apiaceae. It is related to the common fennel (Foeniculum vulgare), which belongs to the same family.
Ferula communis is a tall herbaceous perennial plant. It is found in Mediterranean and East African woodlands and shrublands.
It was known in antiquity as laser
or narthex.
Human use
Its young stems and inflorescences were eaten in ancient Rome, and are still eaten in Morocco today. However, culinary uses of this species are not always safe and poisoning may occur.
In Sardinia two different chemotypes of Ferula communis have been identified: poisonous (especially to animals like sheep, goats, cattle, and horses) and non-poisonous.
They differ in both secondary metabolites patterning and enzymatic composition.
The resin of the subspecies F. communis subsp. brevifolia is called gum ammoniac of Morocco.
The phenolic compound ferulic acid is named for the giant fennel, from which it can be isolated.
In Ancient Greek mythology, Prometheus gave mortals fire by hiding it in the plant's hollow stalk. (cite Aeschylus' Prometheus Bound)
Resin extraction
Since antiquity, the resin of Ferula species has been used for medicinal purposes. The resin, in the form of a sticky latex, was usually extracted from the lower stalk or root, with the root resin being the finest-grade.
Where the resin of giant fennel (Ferula communis) was farmed, a small hole was pierced in its root with a sharp instrument, after clearing away all rocks and earth that cling to the exposed root. A small trench was dug beneath the root and overlayed with several smooth and flat stones at the bottom for collecting the exuded resin. The piercing was made deep enough into the root or lower stalk to ensure a steady flow of resin on its own pressure.
The resin was usually harvested in the dry and hot summer months, when dampness and moisture could not corrupt the resin. The resin hardens when exposed to the air, upon whic |
https://en.wikipedia.org/wiki/Institute%20for%20Astronomy%20and%20Astrophysics | The Institute for Astronomy and Astrophysics (IAA) in Brussels is a part of the physics department of the Université Libre de Bruxelles. It is an international center of excellence in the field of nuclear astrophysics. The institute's director is currently Prof. Alain Jorissen. The institute is composed of one full professor, five tenured FNRS senior researchers, nine postdoctoral fellows from various countries (Belgium, France, Japan, United Kingdom, Slovakia), and three Ph.D. students (Belgium, Italy).
Field of research
Its research interests involve nuclear astrophysics, stellar evolution, chemical composition of stars, binary stars, neutron stars and modified Newtonian dynamics.
Achievements
The institute has been a leading laboratory in many national and international collaborations. One of these collaborations has led to a world premiere, the direct measurement of a nuclear reaction rate on an unstable target at energies of interest in astrophysics |
https://en.wikipedia.org/wiki/Caramel%20color | Caramel color or caramel coloring is a water-soluble food coloring. It is made by heat treatment of carbohydrates (sugars), in general in the presence of acids, alkalis, or salts, in a process called caramelization. It is more fully oxidized than caramel candy, and has an odor of burnt sugar and a somewhat bitter taste. Its color ranges from pale yellow to amber to dark brown.
Caramel color is one of the oldest and most used food colorings for enhancing naturally occurring colors, correcting natural variations in color, and replacing color that is lost to light degradation during food processing and storage. The use of caramel color as a food additive in the brewing industry in the 19th century is the first recorded instance of it being manufactured and used on a wide scale. Today, caramel color is found in many commercially made foods and beverages, including batters, beer, brown bread, buns, chocolate, cookies, cough drops, spirits and liquor such as brandy, rum, and whisky, chocolate-flavored confectionery and coatings, custards, decorations, fillings and toppings, potato chips, dessert mixes, doughnuts, fish and shellfish spreads, frozen desserts, fruit preserves, glucose tablets, gravy, ice cream, pickles, sauces and dressings, soft drinks (especially colas), sweets, vinegar, and more. Caramel color is widely approved for use in food globally but application and use level restrictions vary by country.
Production
Caramel color is manufactured by heating carbohydrates, either alone or in the presence of acids, alkalis, and/or salts. Caramel color is produced from commercially available nutritive sweeteners consisting of fructose, dextrose (glucose), invert sugar, sucrose, malt syrup, molasses, starch hydrolysates, and fractions thereof. The acids that may be used are sulfuric, sulfurous, phosphoric, acetic, and citric acids; the alkalis are ammonium, sodium, potassium, and calcium hydroxides; and the salts are ammonium, sodium, and potassium carbonate, bicarbon |
https://en.wikipedia.org/wiki/Philip%20Morrison | Philip Morrison (November 7, 1915 – April 22, 2005) was a professor of physics at the Massachusetts Institute of Technology (MIT). He is known for his work on the Manhattan Project during World War II, and for his later work in quantum physics, nuclear physics high energy astrophysics, and SETI.
A graduate of Carnegie Tech, Morrison became interested in physics, which he studied at the University of California, Berkeley, under the supervision of J. Robert Oppenheimer. He also joined the Communist Party. During World War II he joined the Manhattan Project's Metallurgical Laboratory at the University of Chicago, where he worked with Eugene Wigner on the design of nuclear reactors.
In 1944 he moved to the Manhattan Project's Los Alamos Laboratory in New Mexico, where he worked with George Kistiakowsky on the development of explosive lenses required to detonate the implosion-type nuclear weapon. Morrison transported the core of the Trinity test device to the test site in the back seat of a Dodge sedan. As leader of Project Alberta's pit crew he helped load the atomic bombs on board the aircraft that participated in the atomic bombing of Hiroshima and Nagasaki. After the war ended, he traveled to Hiroshima as part of the Manhattan Project's mission to assess the damage.
After the war he became a champion of nuclear nonproliferation. He wrote for the Bulletin of the Atomic Scientists, and helped found the Federation of American Scientists and the Institute for Defense and Disarmament Studies. He was one of the few ex-communists to remain employed and academically active throughout the 1950s, but his research turned away from nuclear physics towards astrophysics. He published papers on cosmic rays, and a 1958 paper of his is considered to mark the birth of gamma ray astronomy. He was also known for writing popular science books and articles, and appearing in television programs.
Early life and education
Philip Morrison was born in Somerville, New Jersey, November 7, 19 |
https://en.wikipedia.org/wiki/Isomalathion | Isomalathion is an impurity found in some batches of malathion. Whereas the structure of malation is, generically, RSP(S)(OCH3)2, the connectivity of isomalathion is RSPO(SCH3)(OCH3). It arises by heating malathion. Being significantly more toxic to humans than malathion, it has resulted in human poisonings.
In 1976, numerous malaria workers in Pakistan were poisoned by isomalathion. It is an inhibitor of carboxyesterase. |
https://en.wikipedia.org/wiki/Post%20common%20envelope%20binary | A post-common envelope binary (PCEB) or pre-cataclysmic variable is a binary system consisting of a white dwarf or hot subdwarf and a main-sequence star or a brown dwarf. The star or brown dwarf shared a common envelope with the white dwarf progenitor in the red giant phase. In this scenario the star or brown dwarf loses angular momentum as it orbits within the envelope, eventually leaving a main-sequence star and white dwarf in a short-period orbit. A PCEB will continue to lose angular momentum via magnetic braking and gravitational waves and will eventually begin mass-transfer, resulting in a cataclysmic variable. While there are thousands of PCEBs known, there are only a few eclipsing PCEBs, also called ePCEBs. Even more rare are PCEBs with a brown dwarf as the secondary. A brown dwarf with a mass lower than 20 might evaporate during the common envelope phase and therefore the secondary is supposed to have a mass higher than 20 .
The material ejected from the common envelope forms a planetary nebula. One in five planetary nebulae are ejected from common envelopes, but this might be an underestimate. A planetary nebula formed by a common envelope system usually shows a bipolar structure.
The suspected PCEB HD 101584 is surrounded by a complex nebula. During the common envelope phase the red giant phase of the primary was terminated prematurely, avoiding a stellar merger. The remaining hydrogen envelope of HD 101584 was ejected during the interaction between the red giant and the companion and it now forms the circumstellar medium around the binary.
Many eclipsing post-common envelope binaries show variations in the timing of eclipses, the cause of which is uncertain. While orbiting exoplanets are often proposed as the cause of these variations, planetary models often fail to predict subsequent changes in eclipse timing. Other proposed causes, such as the Applegate mechanism, often cannot fully explain the observed eclipse timing variations either.
List of po |
https://en.wikipedia.org/wiki/Henrik%20I.%20Christensen | Henrik Iskov Christensen (born July 16, 1962 in Frederikshavn, Denmark) is a Danish roboticist and Professor of Computer Science at Dept. of Computer Science and Engineering, at the UC San Diego Jacobs School of Engineering. He is also the Director of the Contextual Robotics Institute at UC San Diego.
Prior to UC San Diego, he was a Distinguished Professor of Computer Science in the School of Interactive Computing at the Georgia Institute of Technology. At Georgia Tech, Christensen served as the founding director of the Institute for Robotics and Intelligent Machines (IRIM@GT) and the KUKA Chair of Robotics.
Previously, Christensen was the Founding Chairman of European Robotics Research Network (EURON) and an IEEE Robotics and Automation Society Distinguished Lecturer in Robotics.
Biography
Christensen received his Certificate of Apprenticeship in Mechanical Engineering from the Frederikshavn Technical School, Denmark in 1981. He received his M.Sc. and Ph.D. in Electrical Engineering from Aalborg University in 1987 and 1990, respectively. His doctoral thesis Aspects of Real Time Image Sequence Analysis was advised by Erik Granum.
After receiving his Ph.D., Christensen held teaching and research positions at Aalborg University, Oak Ridge National Laboratory, and the Royal Institute of Technology. In 2006, Christensen accepted a part-time position at the Georgia Institute of Technology as a Distinguished Professor of Computer Science and the KUKA Chair of Robotics, and transitioned to full-time in early 2007. At Georgia Tech, Christensen served as the founding director of the Center for Robotics and Intelligent Machines (RIM@GT), an interdepartmental research units consists of the College of Computing, College of Engineering, and the Georgia Tech Research Institute (GTRI). During his tenure, RIM@GT experienced an unprecedented growth, including (as of 2008) 36 faculty members as well as a dedicated interdisciplinary Ph.D. program in Robotics.
He joined UC San Die |
https://en.wikipedia.org/wiki/Ground%20field | In mathematics, a ground field is a field K fixed at the beginning of the discussion.
Use
It is used in various areas of algebra:
In linear algebra
In linear algebra, the concept of a vector space may be developed over any field.
In algebraic geometry
In algebraic geometry, in the foundational developments of André Weil the use of fields other than the complex numbers was essential to expand the definitions to include the idea of abstract algebraic variety over K, and generic point relative to K.
In Lie theory
Reference to a ground field may be common in the theory of Lie algebras (qua vector spaces) and algebraic groups (qua algebraic varieties).
In Galois theory
In Galois theory, given a field extension L/K, the field K that is being extended may be considered the ground field for an argument or discussion. Within algebraic geometry, from the point of view of scheme theory, the spectrum Spec(K) of the ground field K plays the role of final object in the category of K-schemes, and its structure and symmetry may be richer than the fact that the space of the scheme is a point might suggest.
In Diophantine geometry
In diophantine geometry the characteristic problems of the subject are those caused by the fact that the ground field K is not taken to be algebraically closed. The field of definition of a variety given abstractly may be smaller than the ground field, and two varieties may become isomorphic when the ground field is enlarged, a major topic in Galois cohomology.
Notes
Field (mathematics) |
https://en.wikipedia.org/wiki/Isotype%20%28picture%20language%29 | Isotype (International System of Typographic Picture Education) is a method of showing social, technological, biological, and historical connections in pictorial form. It consists of a set of standardized and abstracted pictorial symbols to represent social-scientific data with specific guidelines on how to combine the identical figures using serial repetition. It was first known as the Vienna Method of Pictorial Statistics (Wiener Methode der Bildstatistik), due to its having been developed at the Gesellschafts- und Wirtschaftsmuseum in Wien (Social and Economic Museum of Vienna) between 1925 and 1934. The founding director of this museum, Otto Neurath, was the initiator and chief theorist of the Vienna Method. Gerd Arntz was the artist responsible for realising the graphics. The term Isotype was applied to the method around 1935, after its key practitioners were forced to leave Vienna by the rise of Austrian fascism.
Origin and development
The Gesellschafts- und Wirtschaftsmuseum was principally financed by the municipality of Vienna, during a period of expansive municipal social democratic governance known as Red Vienna within the new republic of Austria. An essential task of the museum was to inform the Viennese about their city. Neurath stated that the museum was not a treasure chest of rare objects, but a teaching museum. The aim was to "represent social facts pictorially" and to bring "dead statistics" to life by making them visually attractive and memorable. One of the museum's catch-phrases was: "To remember simplified pictures is better than to forget accurate figures".
The principal instruments of the Vienna Method were pictorial charts, which could be produced in multiple copies and serve both permanent and travelling exhibitions. The museum also innovated with interactive models and other attention-grabbing devices, and there were even some early experiments with animated films.
From its beginning the Vienna Method/Isotype was the work of a team. Neur |
https://en.wikipedia.org/wiki/Deoxyguanosine | Deoxyguanosine is composed of the purine nucleobase guanine linked by its N9 nitrogen to the C1 carbon of deoxyribose. It is similar to guanosine, but with one hydroxyl group removed from the 2' position of the ribose sugar (making it deoxyribose). If a phosphate group is attached at the 5' position, it becomes deoxyguanosine monophosphate.
Deoxyguanosine is one of the four deoxyribonucleosides that make up DNA.
See also
8-Oxo-2'-deoxyguanosine |
https://en.wikipedia.org/wiki/Solvency%20ratio | A solvency ratio measures the extent to which assets cover commitments for future payments, the liabilities.
The solvency ratio of an insurance company is the size of its capital relative to all risks it has taken. The solvency ratio is most often defined as:
The solvency ratio is a measure of the risk an insurer faces of claims that it cannot absorb. The amount of premium written is a better measure than the total amount insured because the level of premiums is linked to the likelihood of claims.
Different countries use different methodologies to calculate the solvency ratio, and have different requirements. For example, in India insurers are required to maintain a minimum ratio of 1.5.
For pension plans, the solvency ratio is the ratio of pension plan assets to liabilities (the pensions to be paid). Another measure of the pension plan's ability to pay all pensions in perpetuity is the going concern ratio, which measures the cost of pensions if the pension plan continues to operate. For the solvency ratio, the pension liabilities are measured using stringent rules including the assumption that the plan will be close immediately so must purchase of annuities to transfer responsibility of the pensions to another party. This is more expensive so the solvency ratio is usually lower than the going concern ratio, which measures the pension plan's ability to pay pensions if it continues to operate.
In finance, the solvency ratio measures a company's cash flow compared to its liabilities:
Solvency ratio = (net income + depreciation) / liabilities
See also
Current ratio
Solvency
Solvency II Directive 2009 the EU requirement on the ratio |
https://en.wikipedia.org/wiki/Th%C3%A9venin%27s%20theorem | As originally stated in terms of direct-current resistive circuits only, Thévenin's theorem states that "Any linear electrical network containing only voltage sources, current sources and resistances can be replaced at terminals by an equivalent combination of a voltage source in a series connection with a resistance ."
The equivalent voltage is the voltage obtained at terminals of the network with terminals open circuited.
The equivalent resistance is the resistance that the circuit between terminals and would have if all ideal voltage sources in the circuit were replaced by a short circuit and all ideal current sources were replaced by an open circuit.
If terminals and are connected to one another, the current flowing from and will be This means that could alternatively be calculated as divided by the short-circuit current between and when they are connected together.
In circuit theory terms, the theorem allows any one-port network to be reduced to a single voltage source and a single impedance.
The theorem also applies to frequency domain AC circuits consisting of reactive (inductive and capacitive) and resistive impedances. It means the theorem applies for AC in an exactly same way to DC except that resistances are generalized to impedances.
The theorem was independently derived in 1853 by the German scientist Hermann von Helmholtz and in 1883 by Léon Charles Thévenin (1857–1926), an electrical engineer with France's national Postes et Télégraphes telecommunications organization.
Thévenin's theorem and its dual, Norton's theorem, are widely used to make circuit analysis simpler and to study a circuit's initial-condition and steady-state response. Thévenin's theorem can be used to convert any circuit's sources and impedances to a Thévenin equivalent; use of the theorem may in some cases be more convenient than use of Kirchhoff's circuit laws.
Calculating the Thévenin equivalent
The equivalent circuit is a voltage source with voltage i |
https://en.wikipedia.org/wiki/Tzanck%20test | In dermatopathology, the Tzanck test, also Tzanck smear, is scraping of an ulcer base to look for Tzanck cells. It is sometimes also called the chickenpox skin test and the herpes skin test. It is a simple, low-cost, and rapid office based test.
Tzanck cells (acantholytic cells) are found in:
Herpes simplex
Varicella and herpes zoster
Pemphigus vulgaris
Cytomegalovirus
Arnault Tzanck did the first cytological examinations in order to diagnose skin diseases. To diagnose pemphigus, he identified acantholytic cells, and to diagnose of herpetic infections he identified multinucleated giant cells and acantholytic cells. He extended his cytologic findings to certain skin tumors as well.
Even though cytological examination can provide rapid and reliable diagnosis for many skin diseases, its use is limited to a few diseases. In endemic regions, Tzanck test is used to diagnose leishmaniasis and leprosy. For other regions, Tzanck test is mainly used to diagnose pemphigus and herpetic infections. Some clinics use biopsies even for herpetic infections. This is because the advantages of this test are not well known, and the main textbooks of dermatopathology do not include dedicated sections for cytology or Tzanck smear. A deep learning model called TzanckNet has been developed to lower the experience barrier needed to use this test.
Procedure
Unroof vesicle and scrape base w/ sterile №15 scalpel blade
Smear with cotton stick onto a clean glass slide
Fix w/ gentle heat or air dry
Fix w/ MeOH (Methanol)
Stain w/ Giemsa, methylene blue or Wright’s stain.
Microscopic examination using an oil immersion lens. (Look for multinucleated giant cells)
A modified test can be performed using proprietary agents which requires fewer steps and allows the sample to be fixed quicker.
Cytologic findings
For microscopic evaluation, samples are first scanned with low magnification objectives (X4 and X10) and then examined in detail with the high magnification objective (X100). The X4 |
https://en.wikipedia.org/wiki/SoundHound | SoundHound AI, Inc. is an audio and speech recognition company founded in 2005. It develops speech recognition, natural language understanding, sound recognition and search technologies. Its featured products include Houndify, a Voice AI developer platform, SoundHound Chat AI, a voice-enabled digital assistant, and music recognition mobile app SoundHound. The company’s headquarters are in Santa Clara, California.
History
The company was founded in 2005 by Keyvan Mohajer, an Iranian-Canadian computer scientist who had founded a number of dot com ventures before starting SoundHound.
In 2009, the company's Midomi app was rebranded as SoundHound but is still available as a web version on midomi.com.
In 2015, SoundHound became the first music recognition service shipping in autos, in a partnership with Hyundai, in the new Genesis model.
By May 2016, SoundHound had over 300 million users globally.
In 2018, SoundHound Inc. announced partnerships with Hyundai, Mercedes-Benz, and Honda to provide voice interaction for their products using its Houndify voice AI platform.
SoundHound won the 2020 Webby Award for Productivity (Voice) in the category Apps, Mobile & Voice.
On November 16 2021, SoundHound announced plans to become a public company via a SPAC merger with Archimedes Tech SPAC Partners Co. On April 28, 2022, the combined company SoundHound AI, Inc. went public, listed under the symbol SOUN on the Nasdaq. In 2022, the company laid off 10% of its staff and enforced salary cuts and it was reported that SoundHound raised less than half of what it originally projected in its SPAC merger deal. In April, 2023, SoundHound secured $100 million in strategic financing.
Funding
According to an article of June 2015 SoundHound Inc. had raised a total of $40 million in funding from Global Catalyst Partners, Translink Capital, Walden Venture Capital, and other investors. This included $7 million in a Series B funding round the company secured in October 2008, bringing total |
https://en.wikipedia.org/wiki/Haken%20manifold | In mathematics, a Haken manifold is a compact, P²-irreducible 3-manifold that is sufficiently large, meaning that it contains a properly embedded two-sided incompressible surface. Sometimes one considers only orientable Haken manifolds, in which case a Haken manifold is a compact, orientable, irreducible 3-manifold that contains an orientable, incompressible surface.
A 3-manifold finitely covered by a Haken manifold is said to be virtually Haken. The Virtually Haken conjecture asserts that every compact, irreducible 3-manifold with infinite fundamental group is virtually Haken. This conjecture was proven by Ian Agol.
Haken manifolds were introduced by . proved that Haken manifolds have a hierarchy, where they can be split up into 3-balls along incompressible surfaces. Haken also showed that there was a finite procedure to find an incompressible surface if the 3-manifold had one. gave an algorithm to determine if a 3-manifold was Haken.
Normal surfaces are ubiquitous in the theory of Haken manifolds and their simple and rigid structure leads quite naturally to algorithms.
Haken hierarchy
We will consider only the case of orientable Haken manifolds, as this simplifies the discussion; a regular neighborhood of an orientable surface in an orientable 3-manifold is just a "thickened up" version of the surface, i.e., a trivial I-bundle. So the regular neighborhood is a 3-dimensional submanifold with boundary containing two copies of the surface.
Given an orientable Haken manifold M, by definition it contains an orientable, incompressible surface S. Take the regular neighborhood of S and delete its interior from M, resulting in M' . In effect, we've cut M along the surface S. (This is analogous, in one less dimension, to cutting a surface along a circle or arc.) It is a theorem that any orientable compact manifold with a boundary component that is not a sphere has an infinite first homology group, which implies that it has a properly embedded 2-sided non-sep |
https://en.wikipedia.org/wiki/Agitator%20%28device%29 | An agitator is a device or mechanism to put something into motion by shaking or stirring. There are several types of agitation machines, including washing machine agitators (which rotate back and forth) and magnetic agitators (which contain a magnetic bar rotating in a magnetic field). Agitators can come in many sizes and varieties, depending on the application.
In general, agitators usually consist of an impeller and a shaft. An impeller is a rotor located within a tube or conduit attached to the shaft. It helps enhance the pressure in order for the flow of a fluid be done. Modern industrial agitators incorporate process control to maintain better control over the mixing process.
Washing machine agitator
In a top load washing machine the agitator projects from the bottom of the wash basket and creates the wash action by rotating back and forth, rolling garments from the top of the load, down to the bottom, then back up again.
There are several types of agitators with the most common being the "straight-vane" and "dual-action" agitators. The "straight-vane" is a one-part agitator with bottom and side fins that usually turns back and forth. The Dual-action is a two-part agitator that has bottom washer fins that move back and forth and a spiral top that rotates clockwise to help guide the clothes to the bottom washer fins.
The modern agitator, which is dual-action, was first made in Kenmore Appliances washing machines in the 1980s to present. These agitators are known by the company as dual-rollover and triple-rollover action agitators.
Magnetic agitator
This is a device formed by a metallic bar (called the agitation bar) which is normally covered by a plastic layer, and a sheet that has underneath it a rotatory magnet or a series of electromagnets arranged in a circular form to create a magnetic rotatory field. Commonly, the sheet has an arrangement of electric resistances that can heat some chemical solutions.
During the operation of a typical magnetic agita |
https://en.wikipedia.org/wiki/Christopher%20Chetsanga | Christopher J. Chetsanga (born 1935 in Murehwa, Rhodesia) is a prominent Zimbabwean scientist who is a member of the African Academy of Sciences and The World Academy of Sciences. He discovered two enzymes involved in DNA repair. He has also held various academic administrative posts like Vice-Chancellor, Director and Dean.
Biography
Chetsanga was born in Murewa, Zimbabwe on 22 August 1935, and was baptised in 1948. In his youth, he was educated at Nhowe Mission, and went on to study at University of California, Berkeley where he received his BSc in 1965. Chetsanga also studied for a period at Pepperdine University. In 1969, he received his MSc and PhD in biochemistry and molecular biology from University of Toronto before becoming a post doctoral fellow at Harvard University between 1969 and 1972. Between 1972 and 1983 he became a professor at the University of Michigan, then in 1983 he left to become the senior lecturer in Biochemistry for University of Zimbabwe. In 1990, President Robert Mugabe awarded him President’s Award for Distinguished Contribution to Science and Technology. Has also awarded the Order of the Star of Zimbabwe. He is presently the vice chancellor at Zimbabwe Ezekiel Guti University.
In 2004, when the Zimbabwe Academy of Sciences was formed, Chetsanga was appointed the first president of the academy. Chetsanga advocated the use of genetically modified food sources as a possible solution for food shortages in Africa in 2020.
Scientific Achievements
Chetsanga has discovered two enzymes involved in the repair of damaged DNA: firstly, formamidopyrimidine DNA glycosylase, which removes damaged 7-methylguanine from DNA (1979), and secondly, purine imidazole-ring cyclase, which re-closes imidazole rings of guanine and adenine damaged by x-irradiation (1985).
According to Chetsanga, his research focus in his scientific career has been on DNA and RNA structural and functional details as they relate to cellular metabolism and disease development |
https://en.wikipedia.org/wiki/Onset%20of%20deconfinement | The onset of deconfinement refers to the beginning of the creation of deconfined states of strongly interacting matter produced in nucleus-nucleus collisions with increasing collision energy (a quark–gluon plasma).
The onset of deconfinement was predicted by Marek Gazdzicki and Mark I. Gorenstein to be located in the low energy range of the Super Proton Synchrotron (SPS) at the European Organization for Nuclear Research (CERN). These predictions have been confirmed by the NA49 experiment at the CERN SPS within the energy scan programme. The most famous of these is the "horn" in the ratio of mean multiplicities of positively charged kaons and pions observed in collisions of two lead nuclei at the low energies of the SPS.
Strangeness production in relativistic heavy-ion collisions is used for the detection of the onset of deconfinement. |
https://en.wikipedia.org/wiki/Guided%20imagery | Guided imagery (also known as guided affective imagery, or katathym-imaginative psychotherapy) is a mind-body intervention by which a trained practitioner or teacher helps a participant or patient to evoke and generate mental images that simulate or recreate the sensory perception of sights, sounds, tastes, smells, movements, and images associated with touch, such as texture, temperature, and pressure, as well as imaginative or mental content that the participant or patient experiences as defying conventional sensory categories, and that may precipitate strong emotions or feelings in the absence of the stimuli to which correlating sensory receptors are receptive.
The practitioner or teacher may facilitate this process in person to an individual or a group or you may do it with a virtual group. Alternatively, the participant or patient may follow guidance provided by a sound recording, video, or audiovisual media comprising spoken instruction that may be accompanied by music or sound.
Mental imagery in everyday life
There are two fundamental ways by which mental imagery is generated: voluntary and involuntary.
The involuntary and spontaneous generation of mental images is integral to ordinary sensory perception, and cognition, and occurs without volitional intent. Meanwhile, many different aspects of everyday problem solving, scientific reasoning, and creative activity involve the volitional and deliberate generation of mental images.
Involuntary
The generation of involuntary mental imagery is created directly from present sensory stimulation and perceptual information, such as when someone sees an object, creates mental images of it, and maintains this imagery as they look away or close their eyes; or when someone hears a noise and maintains an auditory image of it, after the sound ceases or is no longer perceptible.
Voluntary
Voluntary mental imagery may resemble previous sensory perception and experience, recalled from memory; or the images may be entire |
https://en.wikipedia.org/wiki/Kurt%20Grelling | Kurt Grelling (2 March 1886 – September 1942) was a German logician and philosopher, member of the Berlin Circle.
Life and work
Kurt Grelling was born on 2 March 1886 in Berlin. His father, the Doctor of Jurisprudence Richard Grelling, and his mother, Margarethe (née Simon), were Jewish. Shortly after his arrival in 1905 at University of Göttingen, Grelling began a collaboration with philosopher Leonard Nelson, with whom he tried to solve Russell's paradox, which had shaken the foundations of mathematics when it was announced in 1903. Their 1908 paper included new paradoxes, including a semantic paradox that was named the Grelling–Nelson paradox.
He received his doctorate in mathematics from the same university in 1910 with a PhD dissertation on the development of arithmetic in axiomatic set theory, advised by David Hilbert. In a recorded interview with Herbert Enderton, Alfred Tarski mentions a meeting he had with Grelling in 1938, and says that Grelling was the author of the earliest textbook in set theory, probably but wrongly referring to this dissertation, since William Henry Young and Grace Chisholm Young's Set Theory was published in 1906.
As a skilled linguist, Grelling translated philosophical works from French, Italian and English to German, including four of Bertrand Russell's works. He became a strong proponent of Russell's writings thereafter.
From 1911 to 1922 Grelling published exclusively journalistic articles in publications connected with the Social Democratic Party of Germany.
In 1915 his father, Richard Grelling, wrote the anti-war book J'Accuse, condemning the actions of the Central Powers. It enjoyed huge sales outside Germany. Richard followed this success up with Das Verbrechen (The Crime), in which he attacked his critics, who included Kurt Grelling.
From 1924 onwards Grelling's publications were exclusively in the field of positivist philosophy.
Unable to find a university position in either Göttingen or Berlin, Grelling had to te |
https://en.wikipedia.org/wiki/Monogenic%20function | A monogenic function is a complex function with a single finite derivative.
More precisely, a function defined on is called monogenic at , if exists and is finite, with:
Alternatively, it can be defined as the above limit having the same value for all paths. Functions can either have a single derivative (monogenic) or infinitely many derivatives (polygenic), with no intermediate cases. Furthermore, a function which is monogenic , is said to be monogenic on , and if is a domain of , then it is analytic as well (The notion of domains can also be generalized in a manner such that functions which are monogenic over non-connected subsets of , can show a weakened form of analyticity) |
https://en.wikipedia.org/wiki/Microsoft%20Academic | Microsoft Academic was a free internet-based academic search engines for academic publications and literature, developed by Microsoft Research, shut down in 2022. At the same time, OpenAlex was launched and claimed to be a successor to Microsoft Academic.
History
Microsoft Academic gained prominence because it profiled authors, organizations, keywords, and journals and made the dataset available as open data, in contrast to Google Scholar. The search engine indexed over 260 million publications, 88 million of which are journal articles.
Preliminary reviews by bibliometricians suggested the new Microsoft Academic Search was a competitor to Google Scholar, Web of Science, and Scopus for academic research purposes as well as citation analysis. However, it was primarily used as a resource in the field of computer science since that was the most completely indexed information.
On May 4, 2021, Microsoft announced that the Microsoft Academic website and APIs would be retired on December 31, 2021.
Thanks to the open data license, the Microsoft Academic dataset was merged into OpenAlex. However, the underlying software was proprietary and had to be rewritten.
That Microsoft launched and soon after shut down both Microsoft Academic and its predecessor Microsoft Academic Search has been interpreted as a sign that Microsoft "had never intended to enter into the business of scholarly metadata. Instead, the tech giant has been using data on scholarly communication as testing ground for big data and artificial intelligence (AI) technologies".
Technology
The Academic Knowledge API offered information retrieval from the underlying database using REST endpoints for advanced research purposes. The search engine provided not only search results and access to sources but also citation information that include the number of sources, g-index, and h-index. Aside from academic publications, it was also used to find websites that contain state and local records. The technology uses |
https://en.wikipedia.org/wiki/Anthropometric%20measurement%20of%20the%20developing%20fetus | Anthropometry is defined as the scientific study of the human body measurements and proportions. These studies are generally used by clinicians and pathologists for adequate assessments of the growth and development of the fetus at any specific point of gestational maturity. Fetal height, fetal weight, head circumference (HC), crown to rump length (CR), dermatological observations like skin thickness etc. are measured individually to assess the growth and development of the organs and the fetus as a whole and can be a parameter for normal or abnormal development also including adaptation of the fetus to its newer environment.
Another important factor that contributes towards the anthropometric measurement of the human fetal growth is the maternal nutrition and maternal well-being. Malnutrition, as already established by WHO, is a global serious health problem not only in adults but in pregnant and lactating mothers too and is a serious problem in third world countries. In Africa and South Asia, 27%-50% of women in the reproductive age are underweight resulting in 30 million low birth weight babies.
For decades, the topic of question pertaining to crown-rump length (CR), crown-heel length (CH), head circumference (HC) with respect to the body weight of human fetus at different time periods of gestation has baffled many developmental researchers and biostatisticians. These biological variations are all based on linear curves based on human fetuses between 9 and 28 weeks of gestation.
Co-relation of fetal weight and fetal growth
Body weight, for example, is an important function and parameter for growth with respect to gestational age of the fetus. There will be great variations in the body weight of a 16 weeks old fetus. The weight will not be constant for every fetus and will vary from individual to individual. Therefore, rather than an appropriate or standard value, a range can be specified like 90 to 100 grams. This number of variations applies to all other ant |
https://en.wikipedia.org/wiki/Posterior%20atlantoaxial%20ligament | The posterior atlantoaxial ligament is a broad, thin membrane attached, above, to the lower border of the posterior arch of the atlas; below, to the upper edges of the laminæ of the axis.
It supplies the place of the ligamenta flava, and is in relation, behind, with the Obliqui capitis inferiores.
See also
Atlanto-axial joint |
https://en.wikipedia.org/wiki/Evidential%20decision%20theory | Evidential decision theory (EDT) is a school of thought within decision theory which states that, when a rational agent is confronted with a set of possible actions, one should select the action with the highest news value, that is, the action which would be indicative of the best outcome in expectation if one received the "news" that it had been taken. In other words, it recommends to "do what you most want to learn that you will do."
EDT contrasts with causal decision theory (CDT), which prescribes taking the action that will causally produce the best outcome. While these two theories agree in many cases, they give different verdicts in certain philosophical thought experiments. For example, EDT prescribes taking only one box in Newcomb's paradox, while CDT recommends taking both boxes. Functional Decision Theory (FDT) was proposed as an alternative method to more reliably maximize utility, reconciling CDT and EDT.
Formal description
In a 1976 paper, Allan Gibbard and William Harper distinguished between two kinds of expected utility maximization. EDT proposes to maximize the expected utility of actions computed using conditional probabilities, namely
where is the desirability of outcome and is the conditional probability of given that action occurs. This is in contrast to the counterfactual formulation of expected utility used by causal decision theory
where the expression indicates the probability of outcome in the counterfactual situation in which action is performed. Since and are not always equal, these formulations of expected utility are not equivalent, leading to differences in actions prescribed by EDT and CDT.
Thought experiments
Different decision theories are often examined in their recommendations for action in different thought experiments.
Newcomb's paradox
In Newcomb's paradox, there is a predictor, a player, and two boxes designated A and B. The predictor is able to reliably predict the player's choices— say, with 99% accuracy. T |
https://en.wikipedia.org/wiki/Gems%20Sensors%20%26%20Controls | Gems Sensors and Controls is a global manufacturer of application engineered sensors. Founded in 1955, it makes level, pressure and flow sensors for use in a wide range of fluids across industry.
Gems Sensors is a division of Fortive Corporation, a company with a presence around the world. The company provides manufacturing services in North America, Europe, and Asia. It also has sales, engineering, and service offices in different parts of the world.
History
Founded by Edward Moore & Gordon Seigle along with an associate, Gems Sensors & Controls (Gems) has been operational since 1955 and is based in Plainville, Connecticut, USA. Gems Sensors received its first commercial acclaim for a bilge switch developed for the small boating industry.
Products
Gems Sensors Inc. designs and manufactures liquid level, flow switches and pressure switches, miniature solenoid valves, and pre-assembled fluidic systems. The company is also into manufacturing customized level sensors, pressure sensors, proximity switches, solenoid valves, fluidic systems, flow sensors, and Warrick controls. It offers its products to different markets like alternative energy, semiconductor manufacturing, process tank gauging, waste water procession and other marine and industrial applications. |
https://en.wikipedia.org/wiki/Fluo-3 | Fluo-3 is a fluorescence indicator of intracellular calcium (Ca2+), developed by Roger Y. Tsien. It is used to measure Ca2+ inside living cells in flow cytometry, and confocal laser scanning microscopy using visible light excitation (compatible with argon laser sources operating at 488 nm). Fluo-3 and derivatives (Fluo-4, Fluo-5 etc) have also been widely used with two-photon excitation microscopy. Fluo-3 is an essentially nonfluorescent compound, but upon binding of Ca2+ its fluorescence increases sharply with an emission maximum at 525 nm suitable for conventionally used detectors designed for fluorescein isothiocyanate (FITC) measurements. This large change in fluorescence coupled with a good yield of photons provides very high contrast which allowed the detection of microscopic Ca2+ release events inside cells called "Calcium sparks". Whereas the salts of fluo-3 are unable to penetrate cells, loading can be achieved using its acetoxymethyl (AM) ester derivative. Once inside the cell, unspecific esterases cleave the ester effectively trapping fluo-3.
As calcium is a key second messenger within cells, the specific properties of fluo-3 enable researchers to investigate the time-resolved dynamics of intracellular signal transduction in a diverse range of cells. |
https://en.wikipedia.org/wiki/Claw-free%20permutation | In the mathematical and computer science field of cryptography, a group of three numbers (x,y,z) is said to be a claw of two permutations f0 and f1 if
f0(x) = f1(y) = z.
A pair of permutations f0 and f1 are said to be claw-free if there is no efficient algorithm for computing a claw.
The terminology claw free was introduced by Goldwasser, Micali, and Rivest in their 1984 paper, "A Paradoxical Solution to the Signature Problem" (and later in a more complete journal paper), where they showed that the existence of claw-free pairs of trapdoor permutations implies the existence of digital signature schemes secure against adaptive chosen-message attack. This construction was later superseded by the construction of digital signatures from any one-way trapdoor permutation. The existence of trapdoor permutations does not by itself imply claw-free permutations exist; however, it has been shown that claw-free permutations do exist if factoring is hard.
The general notion of claw-free permutation (not necessarily trapdoor) was further studied by Ivan Damgård in his PhD thesis The Application of Claw Free Functions in Cryptography (Aarhus University, 1988), where he showed how to construct
Collision Resistant Hash Functions from claw-free permutations. The notion of claw-freeness is closely related to that of collision resistance in hash functions. The distinction is that claw-free permutations are pairs of functions in which it is hard to create a collision between them, while a collision-resistant hash function is a single function in which it's hard to find a collision, i.e. a function H is collision resistant if it's hard to find a pair of distinct values x,y such that
H(x) = H(y).
In the hash function literature, this is commonly termed a hash collision. A hash function where collisions are difficult to find is said to have collision resistance.
Bit commitment
Given a pair of claw-free permutations f0 and f1 it is straightforward to create a commitment scheme. |
https://en.wikipedia.org/wiki/Future%20Internet | Future Internet is a general term for research activities on new architectures for the Internet.
History
While the technical development of the Internet was an extensive research topic from the beginning, an increased public awareness of several critical shortcomings in terms of performance, reliability, scalability, security and many other categories including societal, economical and business aspects, led to future Internet research efforts.
The time horizon of future Internet studies is typically long term, taking several years before significant deployments take place.
Approaches towards a future Internet range from small, incremental evolutionary steps to complete redesigns (clean slate) and architecture principles, where the applied technologies shall not be limited by existing standards or paradigms such as client server networking, which, for example, might evolve into co-operative peer structures. The fact that an IP address denotes both the identifier as well as the locator of an end system, sometimes referred to as semantic overload, is an example of a conceptual shortcoming of the Internet protocol suite architecture. Approaches called "clean slate" are based on experience that supplementary or late additions to an original and established design are limited in their acceptance and introduction. Technical examples for evolutionary approaches include supplements to existing Internet technology, such as differentiated services, reliable server pooling, SCTP, Locator/Identifier Separation Protocol, Site Multihoming by IPv6 Intermediation or Internet Protocol version 6.
Non-technical aspects of a future Internet span large areas such as socio-economics, business and environmental issues. The Organisation for Economic Co-operation and Development held a conference called "Shaping Policies for a Digital World" in 2008. It proposed activities such as publishing recommendations for the future of the Internet economy.
Research areas that could be seen as co |
https://en.wikipedia.org/wiki/MERSI%20protocol | The MERSI protocol is a cache coherency and memory coherence protocol used by the PowerPC G4. The protocol consists of five states, Modified (M), Exclusive (E), Read Only or Recent (R), Shared (S) and Invalid (I). The M, E, S and I states are the same as in the MESI protocol. The R state is similar to the E state in that it is constrained to be the only clean, valid, copy of that data in the computer system. Unlike the E state, the processor is required to initially request ownership of the cache line in the R state before the processor may modify the cache line and transition to the M state. In both the MESI and MERSI protocols, the transition from the E to M is silent.
For any given pair of caches, the permitted states of a given cache line are as follows: |
https://en.wikipedia.org/wiki/Metabidiminished%20rhombicosidodecahedron | In geometry, the metabidiminished rhombicosidodecahedron is one of the Johnson solids ().
It can be constructed as a rhombicosidodecahedron with two non-opposing pentagonal cupolae () removed.
Related Johnson solids are:
The diminished rhombicosidodecahedron () where one cupola is removed,
The parabidiminished rhombicosidodecahedron () where two opposing cupolae are removed,
The gyrate bidiminished rhombicosidodecahedron () where two non-opposing cupolae are removed and a third is rotated 36 degrees,
And the tridiminished rhombicosidodecahedron () where three cupolae are removed.
External links
Johnson solids |
https://en.wikipedia.org/wiki/Strejc%20method | The Strejc system identification method allows the estimate of the transfer function of a non-periodic, black box-type system based on its step response and is widely used in all branches of industrial and mechanical engineering.
It allows specifically to estimate the order n of the studied system, its time constant and its delay.
To use the Strejc method, it is necessary to apply a step signal to the system and record its tu and tg parameters by observing the inflection point of the response curve. These parameters are then compared with the ones in the numeric table to estimate what order approximates better the system's behaviour and then find the time constant t with the second column (using the appropriate order).
Strejc table
See also
System identification |
https://en.wikipedia.org/wiki/Rubinisphaera | Rubinisphaera is a genus of bacteria from the family of Planctomycetaceae with two known species. Rubinisphaera brasiliensis has been isolated from water from the Lagoa Vermelha from Brazil.
See also
List of bacterial orders
List of bacteria genera |
https://en.wikipedia.org/wiki/Tietze%27s%20graph | In the mathematical field of graph theory, Tietze's graph is an undirected cubic graph with 12 vertices and 18 edges.
It is named after Heinrich Franz Friedrich Tietze, who showed in 1910 that the Möbius strip can be subdivided into six regions that all touch each other – three along the boundary of the strip and three along its center line – and therefore that graphs that are embedded onto the Möbius strip may require six colors. The boundary segments of the regions of Tietze's subdivision (including the segments along the boundary of the Möbius strip itself) form an embedding of Tietze's graph.
Relation to Petersen graph
Tietze's graph may be formed from the Petersen graph by replacing one of its vertices with a triangle.
Like the Tietze graph, the Petersen graph forms the boundary of six mutually touching regions, but on the projective plane rather than on the Möbius strip. If one cuts a hole from this subdivision of the projective plane, surrounding a single vertex, the surrounded vertex is replaced by a triangle of region boundaries around the hole, giving the previously described construction of the Tietze graph.
Hamiltonicity
Both Tietze's graph and the Petersen graph are maximally nonhamiltonian: they have no Hamiltonian cycle, but any two non-adjacent vertices can be connected by a Hamiltonian path. Tietze's graph and the Petersen graph are the only 2-vertex-connected cubic non-Hamiltonian graphs with 12 or fewer vertices.
Unlike the Petersen graph, Tietze's graph is not hypohamiltonian: removing one of its three triangle vertices forms a smaller graph that remains non-Hamiltonian.
Edge coloring and perfect matchings
Edge coloring Tietze's graph requires four colors; that is, its chromatic index is 4. Equivalently, the edges of Tietze's graph can be partitioned into four matchings, but no fewer.
Tietze's graph matches part of the definition of a snark: it is a cubic bridgeless graph that is not 3-edge-colorable. However, most authors restrict snarks to |
https://en.wikipedia.org/wiki/Graphics%20tablet | A graphics tablet (also known as a digitizer, digital graphic tablet, pen tablet, drawing tablet, external drawing pad or digital art board) is a computer input device that enables a user to hand-draw images, animations and graphics, with a special pen-like stylus, similar to the way a person draws images with a pencil and paper. These tablets may also be used to capture data or handwritten signatures. It can also be used to trace an image from a piece of paper that is taped or otherwise secured to the tablet surface. Capturing data in this way, by tracing or entering the corners of linear polylines or shapes, is called digitizing.
The device consists of a rough surface upon which the user may "draw" or trace an image using the attached stylus, a pen-like drawing apparatus. The image is shown on the computer monitor, though some graphic tablets now also incorporate an LCD screen for more realistic or natural experience and usability.
Some tablets are intended as a replacement for the computer mouse as the primary pointing and navigation device for desktop computers.
History
The first electronic handwriting device was the Telautograph, patented by Elisha Gray in 1888.
The first graphic tablet resembling contemporary tablets and used for handwriting recognition by a computer was the Stylator in 1957. Better known (and often misstated as the first digitizer tablet) is the RAND Tablet also known as the Grafacon (for Graphic Converter), introduced in 1964. The RAND Tablet employed a grid of wires under the surface of the pad that encoded horizontal and vertical coordinates in a small electrostatic signal. The stylus received the signal by capacitive coupling, which could then be decoded back as coordinate information.
The acoustic tablet, or spark tablet, used a stylus that generated clicks with a spark plug. The clicks were then triangulated by a series of microphones to locate the pen in space. The system was fairly complex and expensive, and the sensors were |
https://en.wikipedia.org/wiki/Unusual%20number | In number theory, an unusual number is a natural number n whose largest prime factor is strictly greater than .
A k-smooth number has all its prime factors less than or equal to k, therefore, an unusual number is non--smooth.
Relation to prime numbers
All prime numbers are unusual.
For any prime p, its multiples less than p2 are unusual, that is p, ... (p-1)p, which have a density 1/p in the interval (p, p2).
Examples
The first few unusual numbers are
2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 20, 21, 22, 23, 26, 28, 29, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 46, 47, 51, 52, 53, 55, 57, 58, 59, 61, 62, 65, 66, 67, ...
The first few non-prime (composite) unusual numbers are
6, 10, 14, 15, 20, 21, 22, 26, 28, 33, 34, 35, 38, 39, 42, 44, 46, 51, 52, 55, 57, 58, 62, 65, 66, 68, 69, 74, 76, 77, 78, 82, 85, 86, 87, 88, 91, 92, 93, 94, 95, 99, 102, ...
Distribution
If we denote the number of unusual numbers less than or equal to n by u(n) then u(n) behaves as follows:
Richard Schroeppel stated in 1972 that the asymptotic probability that a randomly chosen number is unusual is ln(2). In other words:
External links
Integer sequences |
https://en.wikipedia.org/wiki/Hamiltonian%20fluid%20mechanics | Hamiltonian fluid mechanics is the application of Hamiltonian methods to fluid mechanics. Note that this formalism only applies to nondissipative fluids.
Irrotational barotropic flow
Take the simple example of a barotropic, inviscid vorticity-free fluid.
Then, the conjugate fields are the mass density field ρ and the velocity potential φ. The Poisson bracket is given by
and the Hamiltonian by:
where e is the internal energy density, as a function of ρ.
For this barotropic flow, the internal energy is related to the pressure p by:
where an apostrophe ('), denotes differentiation with respect to ρ.
This Hamiltonian structure gives rise to the following two equations of motion:
where is the velocity and is vorticity-free. The second equation leads to the Euler equations:
after exploiting the fact that the vorticity is zero:
As fluid dynamics is described by non-canonical dynamics, which possess an infinite amount of Casimir invariants, an alternative formulation of Hamiltonian formulation of fluid dynamics can be introduced through the use of Nambu mechanics
See also
Luke's variational principle
Hamiltonian field theory
Notes |
https://en.wikipedia.org/wiki/Silvia%20Heubach | Silvia Heubach is a German-American mathematician specializing in enumerative combinatorics, combinatorial game theory, and bioinformatics. She is a professor of mathematics at California State University, Los Angeles.
Education and career
Heubach earned bachelor's and master's degrees in mathematics and economics from the University of Ulm in 1983 and 1986, respectively. Through a program at the University of Ulm, she came to the University of Southern California (USC) for a one-year exchange, but decided to stay on for a Ph.D. program. She completed a master's degree in mathematics in 1988 and a Ph.D. in applied mathematics at USC in 1992. Her dissertation, A Stochastic Model for the Movement of a White Blood Cell, was supervised by Joseph C. Watkins..
After completing her doctorate, Heubach held visiting faculty positions at Colorado College and Humboldt State University before joining the faculty at California State University, Los Angeles in 1994.
Contributions
Heubach is the co-author of the book Combinatorics of Compositions and Words (with Toufik Mansour, CRC Press, 2009). She is a contributor to a text in bioinformatics, "Concepts in Bioinformatics and Genomics" by Jamil Momand and Alison McCurdy, Oxford University Press, 2016.
Her research in combinatorial game theory has also included analysis of a variant of nim in which piles of pebbles are placed on the edges of a tetrahedron and each move removes at least one pebble from the set of edges incident to a single triangle of the tetrahedron.
Recognition
In 2018, Heubach won the California State University system's Faculty Innovation and Leadership Award, becoming the first professor at the Los Angeles campus of the system to be so honored. The award honored her educational initiatives including developing a new sequence of mathematics courses for life sciences students, developing flipped classroom mathematics courses, and improving statistics courses used to fulfill general education requirements. |
https://en.wikipedia.org/wiki/Cyclic%20number | A cyclic number is an integer for which cyclic permutations of the digits are successive integer multiples of the number. The most widely known is the six-digit number 142857, whose first six integer multiples are
142857 × 1 = 142857
142857 × 2 = 285714
142857 × 3 = 428571
142857 × 4 = 571428
142857 × 5 = 714285
142857 × 6 = 857142
Details
To qualify as a cyclic number, it is required that consecutive multiples be cyclic permutations. Thus, the number 076923 would not be considered a cyclic number, because even though all cyclic permutations are multiples, they are not consecutive integer multiples:
076923 × 1 = 076923
076923 × 3 = 230769
076923 × 4 = 307692
076923 × 9 = 692307
076923 × 10 = 769230
076923 × 12 = 923076
The following trivial cases are typically excluded:
single digits, e.g.: 5
repeated digits, e.g.: 555
repeated cyclic numbers, e.g.: 142857142857
If leading zeros are not permitted on numerals, then 142857 is the only cyclic number in decimal, due to the necessary structure given in the next section. Allowing leading zeros, the sequence of cyclic numbers begins:
(106 − 1) / 7 = 142857 (6 digits)
(1016 − 1) / 17 = 0588235294117647 (16 digits)
(1018 − 1) / 19 = 052631578947368421 (18 digits)
(1022 − 1) / 23 = 0434782608695652173913 (22 digits)
(1028 − 1) / 29 = 0344827586206896551724137931 (28 digits)
(1046 − 1) / 47 = 0212765957446808510638297872340425531914893617 (46 digits)
(1058 − 1) / 59 = 0169491525423728813559322033898305084745762711864406779661 (58 digits)
(1060 − 1) / 61 = 016393442622950819672131147540983606557377049180327868852459 (60 digits)
(1096 − 1) / 97 = 010309278350515463917525773195876288659793814432989690721649484536082474226804123711340206185567 (96 digits)
Relation to repeating decimals
Cyclic numbers are related to the recurring digital representations of unit fractions. A cyclic number of length L is the digital representation of
1/(L + 1).
Conversely, if the digital period of 1/p (where p is prime) is
p − 1,
then |
https://en.wikipedia.org/wiki/Little%E2%80%93Parks%20effect | The Little–Parks effect was discovered in 1962 by William A. Little and Ronald D. Parks in experiments with empty and thin-walled superconducting cylinders subjected to a parallel magnetic field. It was one of the first experiments to indicate the importance of Cooper-pairing principle in BCS theory.
The essence of the Little–Parks (LP) effect is slight suppression of the cylinder's superconductivity by persistent current.
Explanation
The electrical resistance of such cylinders shows a periodic oscillation with the magnetic flux piercing the cylinder, the period being
h/2e ≈
where h is the Planck constant and e is the electron charge. The explanation provided by Little and Parks is that the resistance oscillation reflects a more fundamental phenomenon, i.e. periodic oscillation of the superconducting Tc.
The Little–Parks effect consists in a periodic variation of the Tc with the magnetic flux, which is the product of the magnetic field (coaxial) and the cross sectional area of the cylinder. Tc depends on the kinetic energy of the superconducting electrons. More precisely, the Tc is such temperature at which the free energies of normal and superconducting electrons are equal, for a given magnetic field. To understand the periodic oscillation of the Tc, which constitutes the Little–Parks effect, one needs to understand the periodic variation of the kinetic energy. The kinetic energy oscillates because the applied magnetic flux increases the kinetic energy while superconducting vortices, periodically entering the cylinder, compensate for the flux effect and reduce the kinetic energy. Thus, the periodic oscillation of the kinetic energy and the related periodic oscillation of the critical temperature occur together.
The Little–Parks effect is a result of collective quantum behavior of superconducting electrons. It reflects the general fact that it is the fluxoid rather than the flux which is quantized in superconductors.
The Little–Parks effect can be seen as a |
https://en.wikipedia.org/wiki/Welteislehre | Welteislehre (WEL; "World Ice Theory" or "World Ice Doctrine"), also known as Glazial-Kosmogonie (Glacial Cosmogony), is a discredited cosmological concept proposed by Hanns Hörbiger, an Austrian engineer and inventor. According to his ideas, ice was the basic substance of all cosmic processes, and ice moons, ice planets, and the "global ether" (also made of ice) had determined the entire development of the universe. Hörbiger did not arrive at his ideas through research, but said that he had received it in a "vision" in 1894. He published a book about the theory in 1912 and heavily promoted it in subsequent years, through lectures, magazines and associations.
History
By his own account, Hörbiger was observing the Moon when he was struck by the notion that the brightness and roughness of its surface were due to ice. Shortly after, he experienced a dream in which he was floating in space watching the swinging of a pendulum which grew longer and longer until it broke. "I knew that Newton had been wrong and that the sun's gravitational pull ceases to exist at three times the distance of Neptune," he concluded. He worked out his concepts in collaboration with amateur astronomer and schoolteacher Philipp Fauth whom he met in 1898, and published it as Glazial-Kosmogonie in 1912. Fauth had previously produced a large (if somewhat inaccurate) lunar map and had a considerable following, which lent Hörbiger's ideas some respectability.
It did not receive a great deal of attention at the time, but following World War I Hörbiger decided to change his strategy by promoting the new "cosmic truth" not only to people at universities and academies, but also to the general public. Hörbiger thought that if "the masses" accepted his ideas, then they might put enough pressure on the academic establishment to force his ideas into the mainstream. No effort was spared in popularising the ideas: "cosmotechnical" societies were founded, which offered public lectures that attracted large au |
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/Bessie%20Niemeyer%20Marshall | Bessie Niemeyer Marshall was an American botanical illustrator known for her watercolor paintings of the wildflowers of Lee Memorial Park. Her artwork documented the variety of plant species being preserved in Lee Memorial Park, a Works Progress Administration-funded wildflower and bird sanctuary in Petersburg, Virginia.
Born Sarah Elizabeth Niemeyer on December 25, 1884, in Portsmouth, Virginia, Bessie Niemeyer married Myron Barrand Marshall, an Episcopalian priest, in 1907 and had nine children. After service in parishes in the Philippines and in Virginia, the family settled in Petersburg in 1937.
In 1935, the city of Petersburg, using W.P.A. (Women's and Professional Division) funds, authorized the creation of a 25-acre wildflower sanctuary in Lee Memorial Park. Under the direction of Petersburg Garden Club member Mary Donald Claiborne Holden, African American women labored on the project through 1940, clearing ravines, building ten miles of paths, and planting 365,00 plants, including 8,000 trees and 37,000 shrubs and more than one million honeysuckle roots to prevent erosion. In 1937, Holden hired Marshall to paint watercolors of the dried and pressed plant specimens of Lee Park flora. A self-taught artist, Marshall produced 238 watercolors of the Lee Park herbarium specimens; the paintings and 325 specimens were stored together in fourteen brown scrapbooks, ultimately housed for almost fifty years in the Petersburg Public Library. The collection was rediscovered by the Petersburg Garden Club in the 1990s. The current location of the collection is at Lewis Ginter Botanical Garden.
Although she pursued other illustration assignments, Marshall had no other major commissions. She died on February 14, 1960, in Portsmouth, Virginia.
Lee Memorial Park is now on the National Register of Historic Places. Marshall and the Lee Park W.P.A. project are the subjects of a monograph published in 2000. In 2014, fourteen reproductions of Marshall's paintings were exh |
https://en.wikipedia.org/wiki/Universality%20class | In statistical mechanics, a universality class is a collection of mathematical models which share a single scale invariant limit under the process of renormalization group flow. While the models within a class may differ dramatically at finite scales, their behavior will become increasingly similar as the limit scale is approached. In particular, asymptotic phenomena such as critical exponents will be the same for all models in the class.
Some well-studied universality classes are the ones containing the Ising model or the percolation theory at their respective phase transition points; these are both families of classes, one for each lattice dimension. Typically, a family of universality classes will have a lower and upper critical dimension: below the lower critical dimension, the universality class becomes degenerate (this dimension is 2d for the Ising model, or for directed percolation, but 1d for undirected percolation), and above the upper critical dimension the critical exponents stabilize and can be calculated by an analog of mean-field theory (this dimension is 4d for Ising or for directed percolation, and 6d for undirected percolation).
List of critical exponents
Critical exponents are defined in terms of the variation of certain physical properties of the system near its phase transition point. These physical properties will include its reduced temperature , its order parameter measuring how much of the system is in the "ordered" phase, the specific heat, and so on.
The exponent is the exponent relating the specific heat C to the reduced temperature: we have . The specific heat will usually be singular at the critical point, but the minus sign in the definition of allows it to remain positive.
The exponent relates the order parameter to the temperature. Unlike most critical exponents it is assumed positive, since the order parameter will usually be zero at the critical point. So we have .
The exponent relates the temperature with the system's respo |
https://en.wikipedia.org/wiki/Federico%20Cafiero | Federico Cafiero (24 May 1914 – 7 May 1980) was an Italian mathematician known for his contributions in real analysis, measure and integration theory, and in the theory of ordinary differential equations. In particular, generalizing the Vitali convergence theorem, the Fichera convergence theorem and previous results of Vladimir Mikhailovich Dubrovskii, he proved a necessary and sufficient condition for the passage to the limit under the sign of integral: this result is, in some sense, definitive. In the field of ordinary differential equations, he studied existence and uniqueness problems under very general hypotheses for the left member of the given first order equation, developing an important approximation method and proving a fundamental uniqueness theorem.
Life and academic career
Cafiero was born in Riposto, Province of Catania, on May 24, 1914. He obtained his Laurea in mathematics, cum laude, from the University of Naples Federico II in 1939. During the 1939–1940 academic year, he won an "Istituto Nazionale di Alta Matematica" scholarship and went in Rome to the institute: there he followed the courses held by Francesco Severi, Mauro Picone, Luigi Fantappiè, Giulio Krall and Leonida Tonelli.
The World War II years: 1941–1943
He was appointed instructor of the course of "Elementi di matematica" by the Faculty of Statistical Sciences of the University of Rome, for the 1940–1941 academic year: however, he was able to hold the course only for few months, since he was called to arms in January 1941 and stationed from May 1942 to September 1943 on the Northern African coasts as an officer of the San Marco Battalion. It was there that, after having successfully completed a dangerous sabotage operation, the Armistice between Italy and Allied armed forces surprised him and the other members of his unit, leaving them without any support. Nonetheless, in desperate conditions, he was able to lead his men to the Italian coasts with a rubber dinghy, and was awarded o |
https://en.wikipedia.org/wiki/Stable%20polynomial | In the context of the characteristic polynomial of a differential equation or difference equation, a polynomial is said to be stable if either:
all its roots lie in the open left half-plane, or
all its roots lie in the open unit disk.
The first condition provides stability for continuous-time linear systems, and the second case relates to stability
of discrete-time linear systems. A polynomial with the first property is called at times a Hurwitz polynomial and with the second property a Schur polynomial. Stable polynomials arise in control theory and in mathematical theory
of differential and difference equations. A linear, time-invariant system (see LTI system theory) is said to be BIBO stable if every bounded input produces bounded output. A linear system is BIBO stable if its characteristic polynomial is stable. The denominator is required to be Hurwitz stable if the system is in continuous-time and Schur stable if it is in discrete-time. In practice, stability is determined by applying any one of several stability criteria.
Properties
The Routh–Hurwitz theorem provides an algorithm for determining if a given polynomial is Hurwitz stable, which is implemented in the Routh–Hurwitz and Liénard–Chipart tests.
To test if a given polynomial P (of degree d) is Schur stable, it suffices to apply this theorem to the transformed polynomial
obtained after the Möbius transformation which maps the left half-plane to the open unit disc: P is Schur stable if and only if Q is Hurwitz stable and . For higher degree polynomials the extra computation involved in this mapping can be avoided by testing the Schur stability by the Schur-Cohn test, the Jury test or the Bistritz test.
Necessary condition: a Hurwitz stable polynomial (with real coefficients) has coefficients of the same sign (either all positive or all negative).
Sufficient condition: a polynomial with (real) coefficients such that
is Schur stable.
Product rule: Two polynomials f and g are stable (of th |
https://en.wikipedia.org/wiki/Monas%20Hieroglyphica | Monas Hieroglyphica (or The Hieroglyphic Monad) is a book by John Dee, the Elizabethan magus and court astrologer of Elizabeth I of England, published in Antwerp in 1564. It is an exposition of the meaning of an esoteric symbol that he invented.
Dee's Monas Hieroglyphica presents a complex emblem constructed from various astrological symbols, with elements of Latin wordplay, capitalization, spacing, and diacritics, rendering its interpretation challenging. The symbol is intended to embody a profound concept, representing the unity of all creation influenced by celestial forces. Dee believed that this symbol contained the essence of alchemical transformation and spiritual evolution, and by meditating upon it, he aimed to access hidden knowledge transcending linguistic barriers. In merging astrology, alchemy, mysticism, and metaphysics, the Hieroglyphic Monad serves as a visual manifestation of Dee's interconnected worldview.
Content
Understanding the text is difficult because of Dee's Latin wordplay, unexplained capitalization, odd spacing and diacritics.
Meaning of the symbol
John Dee intended the Monad to incorporate a wide range of mystical and esoteric concepts. This complex symbol was meant to symbolize the unity of all creation, influenced by astrological and planetary forces. Dee believed it held the essence of alchemical transformation and spiritual growth. By meditating on the Monad, he thought to gain insights into hidden knowledge about the universe, transcending language barriers and tapping into profound truths. Overall, Dee's intention was to encapsulate his interconnected worldview, combining elements of astrology, alchemy, mysticism, and metaphysics.
Reception and influence
The book received little notice in English sources, though it is praised in the 1591 edition of George Ripley's The Compound of Alchymy as well as in Elias Ashmole’s Theatrum Chemicum Britannicum (1652). A number of references appear in other languages, for example, Jean-Ja |
https://en.wikipedia.org/wiki/Russula%20densifolia | Russula densifolia, commonly known as the crowded russula or the reddening russula, is a species of agaric fungus in the family Russulaceae. It was first described in 1833 and given its current name in 1876. A widespread species, it is found in Asia, Europe, and North America, where it fruits on the ground in mixed and deciduous forests. Fruit bodies (mushrooms) are robust and squat, with caps up to in diameter, and stems that are long by thick. The mushrooms are characterized by the red and then black color changes that occur in the flesh when it is bruised, and a relatively thick cap cuticle. Although the mushroom is sold as an edible species in some areas of Asia, it is mild to moderately toxic, and may cause gastrointestinal upset if consumed. Several bioactive compounds have been isolated and identified from the mushroom.
Taxonomy
The species was first described by Louis Secretan in 1833 as Agaricus adustus var. densifolius. In 1876, Claude-Casimir Gillet transferred it to the genus Russula. Russula densifolia is classified in the section Nigricantes of Russula subgenus Compactae, which consists of species with robust, squat fruit bodies that discolor to brown or black.
Robert Shaffer defined four forms of R. densifolia in a 1962 monograph on section Compactae, differentiating them by spore print color, fruiting pattern, odor, gill spacing, and the intensity of the color change with bruising. Three forms are from the Pacific Northwest region of North America: form dilatoria has fruit bodies that darken to lavender gray to brownish gray; form fragrans has a fragrant odor and widely spaced gills; form cremeispora produces a light yellow spore print and has an obscurely two-layered cap cuticle. Form gregata, found in the eastern United States, grows gregariously in jack pine and Scotch pine forests. The nomenclatural database Index Fungorum lumps these forms, as well as f. subrubescen, published by Patrick Reumaux in 1996, together into synonymy. Other synon |
https://en.wikipedia.org/wiki/Reversible%20cellular%20automaton | A reversible cellular automaton is a cellular automaton in which every configuration has a unique predecessor. That is, it is a regular grid of cells, each containing a state drawn from a finite set of states, with a rule for updating all cells simultaneously based on the states of their neighbors, such that the previous state of any cell before an update can be determined uniquely from the updated states of all the cells. The time-reversed dynamics of a reversible cellular automaton can always be described by another cellular automaton rule, possibly on a much larger neighborhood.
Several methods are known for defining cellular automata rules that are reversible; these include the block cellular automaton method, in which each update partitions the cells into blocks and applies an invertible function separately to each block, and the second-order cellular automaton method, in which the update rule combines states from two previous steps of the automaton. When an automaton is not defined by one of these methods, but is instead given as a rule table, the problem of testing whether it is reversible is solvable for block cellular automata and for one-dimensional cellular automata, but is undecidable for other types of cellular automata.
Reversible cellular automata form a natural model of reversible computing, a technology that could lead to ultra-low-power computing devices. Quantum cellular automata, one way of performing computations using the principles of quantum mechanics, are often required to be reversible. Additionally, many problems in physical modeling, such as the motion of particles in an ideal gas or the Ising model of alignment of magnetic charges, are naturally reversible and can be simulated by reversible cellular automata.
Properties related to reversibility may also be used to study cellular automata that are not reversible on their entire configuration space, but that have a subset of the configuration space as an attractor that all initially ran |
https://en.wikipedia.org/wiki/Global%20Action%20Fund%20for%20Fungal%20Infections | The Global Action For Fungal Infections (GAFFI), is an international foundation focussed on raising awareness of and collecting worldwide data on fungal disease. Its aim is to make reliable and inexpensive diagnostic tests widely available.
In 2015, GAFFI proposed action to make affordable fungal diagnostic tests and antifungal treatments available to 95% of the world's population by 2025. In 2018 GAFFI calculated that globally around one billion people have fungal infections of the skin, more than one million people become blind from fungal keratitis, more than 10 million people develop lung disease after breathing in fungal spores, and more than 300 million people have a severe fungal infection every year, of whom over 1.5 million die.
Location and members
The GAFFI is based in Switzerland and the United Kingdom. Its Board Chair is Oddi Aasheim.
Aims
GAFFI is an international foundation focussed on raising awareness of and collecting worldwide data on fungal disease burden. Its primary aims are to get reliable and inexpensive diagnostic tests to be widely available, particularly in low and middle income countries. The tests can be produced but the increasing cost of regulatory approval causes difficulty in getting them from the experimental stage in the laboratory to real world use in clinics.
Activities
GAFFI has successfully advocated for multiple diagnostics as Essential to be listed on the World Health Organization's EDL. GAFFI tracks country registration and access to Essential Medicines for antifungal agents.
GAFFI also estimates and publicises data on fungal diseases incidence and prevalence (burden).
The GAFFI was launched in London in 2013. In 2015, GAFFI proposed action to make fungal diagnostic tests and antifungal treatments available to 95% of the world's population by 2025 95/95 by 2025. Six actions were proposed:
Provide rapid diagnostic tests that do not rely on culture, and that are affordable.
Establish at least one laboratory in each cou |
https://en.wikipedia.org/wiki/Hypophysitis | Hypophysitis refers to an inflammation of the pituitary gland. Hypophysitis is rare and not fully understood.
Signs and symptoms
There are four categories of symptoms and signs. Most commonly, the initial symptoms are headaches and visual disturbances. Some symptoms are derived from the lesser functioning of the adenohypophyseal hormones. Of the adenohypophyseal hormones, the most frequently affected are corticotropes, lactotropes and gonadotropes, all which are found in the anterior pituitary. Polyuria is also a common symptom – which results in very dilute urine, as well as polydipsia which means having extreme thirst. Another symptom is hyperprolactinemia, which is when there are abnormally high prolactin levels in the blood. Usually, a mass will be found located on the sella turcica and loss of hormonal function.
Cause
Hypophysitis may have an underlying autoimmune aetiology, as in the case of autoimmune hypophysitis, and lymphocytic hypophysitis.
Diagnosis
Mainly, the diagnosis of hypophysitis is through exclusion – patients often undergo surgery because they are suspected of having a pituitary adenoma. But, the most accurate diagnosis is using Magnetic Resonance Imaging (MRI) to find any mass or lesions on the sella turcica. It is a known side-effect of the new immune checkpoint inhibitors of the CTLA-4 inhibitor and PD-L1 inhibitor classes, used for the treatment of melanoma, and should be considered in patients on these drugs who present with endocrine dysfunction.
Treatment
It was shown through various testing that administration of bromocriptine can improve field of vision defects and lower prolactin levels. It was also found that when using corticosteroids, there was a decrease in size of the gland, and relieved compression on the dura mater. These corticosteroids were also found to have an immunosuppressive effect which helped with reducing the autoimmune reaction of the gland.
Prognosis
The prognosis for hypophysitis was variable for each ind |
https://en.wikipedia.org/wiki/Optical%20depth%20%28astrophysics%29 | Optical depth in astrophysics refers to a specific level of transparency. Optical depth and actual depth, and respectively, can vary widely depending on the absorptivity of the astrophysical environment. Indeed, is able to show the relationship between these two quantities and can lead to a greater understanding of the structure inside a star.
Optical depth is a measure of the extinction coefficient or absorptivity up to a specific 'depth' of a star's makeup.
The assumption here is that either the extinction coefficient or the column number density is known. These can generally be calculated from other equations if a fair amount of information is known about the chemical makeup of the star. From the definition, it is also clear that large optical depths correspond to higher rate of obscuration. Optical depth can therefore be thought of as the opacity of a medium.
The extinction coefficient can be calculated using the transfer equation. In most astrophysical problems, this is exceptionally difficult to solve since solving the corresponding equations requires the incident radiation as well as the radiation leaving the star. These values are usually theoretical.
In some cases the Beer–Lambert law can be useful in finding .
where is the refractive index, and is the wavelength of the incident light before being absorbed or scattered. It is important to note that the Beer–Lambert law is only appropriate when the absorption occurs at a specific wavelength, . For a gray atmosphere, for instance, it is most appropriate to use the Eddington Approximation.
Therefore, is simply a constant that depends on the physical distance from the outside of a star. To find at a particular depth , the above equation may be used with and integration from to .
The Eddington approximation and the depth of the photosphere
Since it is difficult to define where the interior of a star ends and the photosphere begins, astrophysicists usually rely on the Eddington Appro |
https://en.wikipedia.org/wiki/Dixie%20Flag%20Manufacturing%20Company | The Dixie Flag Manufacturing Company, based in San Antonio, Texas, is a prominent U.S. flag manufacturer. The company was founded in 1858.
In June 2015, following the events of the Charleston church shooting, the company announced that it would no longer sell Confederate flags. |
https://en.wikipedia.org/wiki/UQCR11 | UQCR11 (ubiquinol-cytochrome c reductase, complex III sub-unit XI) is a protein that in humans is encoded by the UQCR11 gene. UQCR11 is the smallest known component of Complex III in the mitochondrial respiratory chain.
Structure
The UQCR11 gene, located on the p arm of chromosome 19 in position 13.3, is made up of 3 exons and is 8,329 base pairs in length. The UQCR11 protein weighs 6.6 kDa and is composed of 56 amino acids. This gene encodes the smallest known component of the ubiquinol-cytochrome c reductase complex, which is also known as Complex III and is part of the mitochondrial respiratory chain. In vertebrates, Complex III contains 11 sub-units: 3 respiratory sub-units, 2 core proteins and 6 low-molecular weight proteins. Proteobacterial complexes may contain as few as three sub-units.
Function
The UQCR11 protein may function as a binding factor for the iron-sulfur protein in Complex III, which is ubiquitous in human cells. Complex III catalyzes the chemical reaction
QH2 + 2 ferricytochrome c Q + 2 ferrocytochrome c + 2 H+
Thus, the two substrates of Complex III are dihydroquinone (QH2) and ferri- (Fe3+) cytochrome c, whereas its 3 products are quinone (Q), ferro- (Fe2+) cytochrome c, and H+. This complex belongs to the family of oxidoreductases, specifically those acting on diphenols and related substances as donor with a cytochrome as acceptor. This enzyme participates in oxidative phosphorylation. It has four cofactors: cytochrome c1, cytochrome b-562, cytochrome b-566 and a 2-Iron ferredoxin of the Rieske type. |
https://en.wikipedia.org/wiki/List%20of%20electrical%20engineers | This is a list of electrical engineers (by no means exhaustive), people who have made notable contributions to electrical engineering or computer engineering.
See also
List of engineers - for lists of engineers from other disciplines
List of Russian electrical engineers
Engineers
Electrical Engineers |
https://en.wikipedia.org/wiki/Morpheein | Morpheeins are proteins that can form two or more different homo-oligomers (morpheein forms), but must come apart and change shape to convert between forms. The alternate shape may reassemble to a different oligomer. The shape of the subunit dictates which oligomer is formed. Each oligomer has a finite number of subunits (stoichiometry). Morpheeins can interconvert between forms under physiological conditions and can exist as an equilibrium of different oligomers. These oligomers are physiologically relevant and are not misfolded protein; this distinguishes morpheeins from prions and amyloid. The different oligomers have distinct functionality. Interconversion of morpheein forms can be a structural basis for allosteric regulation, an idea noted many years ago, and later revived. A mutation that shifts the normal equilibrium of morpheein forms can serve as the basis for a conformational disease. Features of morpheeins can be exploited for drug discovery. The dice image (Fig 1) represents a morpheein equilibrium containing two different monomeric shapes that dictate assembly to a tetramer or a pentamer. The one protein that is established to function as a morpheein is porphobilinogen synthase, though there are suggestions throughout the literature that other proteins may function as morpheeins (for more information see "Table of Putative Morpheeins" below).
Implications for drug discovery
Conformational differences between subunits of different oligomers and related functional differences of a morpheein provide a starting point for drug discovery. Protein function is dependent on the oligomeric form; therefore, the protein's function can be regulated by shifting the equilibrium of forms. A small molecule compound can shift the equilibrium either by blocking or favoring formation of one of the oligomers. The equilibrium can be shifted using a small molecule that has a preferential binding affinity for only one of the alternate morpheein forms. An inhibitor of porp |
https://en.wikipedia.org/wiki/Journal%20of%20Business%20%26%20Economic%20Statistics | The Journal of Business & Economic Statistics is a quarterly peer-reviewed academic journal published by the American Statistical Association. The journal covers a broad range of applied problems in business and economic statistics, including forecasting, seasonal adjustment, applied demand and cost analysis, applied econometric modeling, empirical finance, analysis of survey and longitudinal data related to business and economic problems, the impact of discrimination on wages and productivity, the returns to education and training, the effects of unionization, and applications of stochastic control theory to business and economic problems.
See also
List of scholarly journals in economics |
https://en.wikipedia.org/wiki/Flag%20of%20Antigua%20and%20Barbuda | The national flag of Antigua and Barbuda was adopted on 27 February 1967 to mark the achievement of self-government. A competition to design the flag was held in which more than 600 local people entered. The winning design was put forth by nationally well-known artist and sculptor Sir Reginald Samuel.
Design and symbolism
The design is a red field with an inverted isosceles triangle based on the top edge of the field pointed toward the bottom edge of the field bearing the horizontal tricolour of black, light blue (half width) and white with the rising sun centred on top of the black band. The rising sun symbolises the dawning of a new era.
The colours have different meanings: the black is for the African ancestry of the people; the blue for hope; and the red for energy or life of the people. The successive colouring of black, yellow, blue, and white (from the sun down) also stands for the soil, sun, sea, and sand. The blue also represents the Caribbean Sea, and the V-shape is the symbol of victory. The seven points on the flag represent each of the six parishes, and, the island of Barbuda.
The state ensign, which is used only by the national coast guard, consists of a white field, a red cross, and the state flag in the canton.
Colours
No official specification of the colour shades is known for this flag. The French Navy's flag book Album des pavillons suggests the following Pantone colours: Red 186c, Blue 300c and Yellow 116c.
Viceregal flags
Flags of Barbuda
Historical flags
Political flags |
https://en.wikipedia.org/wiki/Oudemansin%20A | Oudemansin A is a natural product first isolated from the basidiomycete fungus Oudemansiella mucida. Its chemical structure was determined by X-ray crystallography in 1979 and absolute stereochemistry by total synthesis. Two closely related derivatives, oudemansin B and X have also been isolated from other basidiomycetes. They are all biologically active against many filamentous fungi and yeasts but with insufficient potency and stability to become useful commercial products. However, their discovery, together with the strobilurins led to agricultural fungicides including azoxystrobin with the same mechanism of action.
Isolation and Characterization
Oudemansin A (initially known simply as oudemansin) with R1 = R2 = H was first described in 1979, after being isolated from mycelial fermentations of the basidiomycete fungus Oudemansiella mucida. Its structure, including the relative configuration of the methoxy and adjacent methyl groups, was established by both spectroscopic methods and single crystal X-ray analysis but its absolute stereochemistry was at that time undetermined.
Later it was found in cultures of the basidiomycete fungi Mycena polygramma and Xerula melanotricha. The latter fungus also produces oudemansin B, with R1 = MeO and R2 = Cl. Oudemansin X, with R1 = H and R2 = MeO was isolated from Oudemansiella radicata.
Chemical synthesis
The oudemansins have been targets for total synthesis and in 1983, the synthesis of (-)-oudemansin A established that all three compounds have the (9S,10S)-configuration. Routes to oudemansins B and X have also been reported.
Mechanism of action as fungicides
The fungicidal effects were shown to stem from what was then a novel mode of action, QoI inhibition. This was related to the β-methoxyacrylic acid sub-structure which this and related natural products, the strobilurins have in common. Intensive research by several agrochemical companies led to the development of useful agricultural fungicides based on the same mode |
https://en.wikipedia.org/wiki/Heuriger | In eastern Austria, a Heuriger (; Austrian dialect pronunciation: Heiriga) is a tavern where local winemakers serve their new wine under a special licence in alternating months during the growing season. Each state in Austria has slightly varying rules on how many Heuriger of a town can be open at any given time and for how long in total during the year. The Heurige are renowned for their atmosphere of Gemütlichkeit shared among a throng enjoying young wine, simple food, and – in some places – Schrammelmusik. They correspond to the Straußwirtschaften in the German Rheinland, the Frasche in Friuli-Venezia Giulia, and Osmica in Slovenia.
Heuriger is the abbreviation of "heuriger Wein" (this year's wine) in Austrian and Bavarian German. Originally, they were simple open-air taverns on the premises of winemakers, where people would bring along food and drink the new wine. Nowadays, the taverns are often situated at a distance from the wineyards and offer both food and drinks. Heurige where apple or pear cider is served are called Mostheurige. In the well-known wine-growing areas of the city of Vienna (Grinzing, Sievering, Neustift, Liesing) many eating establishments have a rustic interior design similar to Heurige, yet they have a normal licence and sell wine they buy from outside sources.
History
On 17 August 1784 Austrian Emperor Joseph II issued a decree that permitted all residents to open establishments to sell and serve self-produced wine and juices. At first no food could be sold in order to prevent competition with restaurants, but over time these restrictions lessened.
Ausg'steckt would be a sign that the wine farmer was serving out the wine at a Heuriger.
Over the years well-known areas for Heurigen developed, including Dürnstein, Gainfarn, Gamlitz, Guntramsdorf, Gumpoldskirchen, Grinzing, Königstetten, Langenlois, Mauer, Neustift am Walde, Perchtoldsdorf, Pfaffstätten, Rust, Sievering, Traiskirchen, Tribuswinkel and the Wachau region.
Many of the town |
https://en.wikipedia.org/wiki/Stauropteridaceae | Stauropteridaceae is a family of ferns or fern-like plants from the Devonian and Upper Carboniferous. |
https://en.wikipedia.org/wiki/Wizzy%20Active%20Lifestyle%20Telephone | The Wizzy Active Lifestyle Telephone (W.A.L.T.) was a prototype "phone companion" created by Apple Computer in collaboration with BellSouth. W.A.L.T. featured "touchscreen, fax functionality, on-display caller ID, a built-in address book, customizable ringtones, and online banking access". The system was based on the PowerBook 100, and included touchscreen, stylus, and handwriting recognition. The operating system was based on System 6 with a HyperCard GUI. Announced in 1993, the system was not mass-produced. A prototype machine was sold on eBay in 2012 for US$8,000. In 2019 a video demonstration of a prototype machine was uploaded to the internet. |
https://en.wikipedia.org/wiki/FoundationDB | FoundationDB is a free and open-source multi-model distributed NoSQL database developed by Apple Inc. with a shared-nothing architecture. The product was designed around a "core" database, with additional features supplied in "layers." The core database exposes an ordered key–value store with transactions. The transactions are able to read or write multiple keys stored on any machine in the cluster while fully supporting ACID properties. Transactions are used to implement a variety of data models via layers.
The FoundationDB Alpha program began in January 2012 and concluded on March 4, 2013, with their public Beta release. Their 1.0 version was released for general availability on August 20, 2013. On March 24, 2015, it was reported that Apple has acquired the company. A notice on the FoundationDB web site indicated that the company has "evolved" its mission and would no longer offer downloads of the software.
On April 19, 2018, Apple open sourced the software, releasing it under the Apache 2.0 license.
Main features
The main features of FoundationDB included the following:
Ordered key–value store
In addition to supporting standard key-based reads and writes, the ordering property enables range reads that can efficiently scan large swaths of data.
Transactions
Transaction processing employs multiversion concurrency control for reads and optimistic concurrency for writes. Transactions can span multiple keys stored on multiple machines.
ACID properties
FoundationDB guarantees serializable isolation and strong durability via redundant storage on disk before transactions are considered committed.
Layers
Layers map new data models, APIs, and query languages to the FoundationDB core. They employ FoundationDB's ability to update multiple data elements in a single transaction, ensuring consistency. An example is their SQL layer.
Commodity clusters
FoundationDB is designed for deployment on distributed clusters of commodity hardware running Linux.
Replica |
https://en.wikipedia.org/wiki/Florida%20Citrus%20Archives | The Florida Citrus Archives are designated by law as the official citrus archive of Florida.
The designation occurred in 2001. The Senate bill analysis stated "Florida Southern College in Lakeland has accumulated and maintains an extensive collection of citrus related materials. The collection is called The Florida Citrus Archives and is dedicated to Thomas B. Mack, the person most responsible for the success of the project. Florida Citrus Mutual, an association representing growers statewide, maintains that The Florida Citrus Archives are the largest collection of its kind by far and that they function now as the unofficial statewide citrus archives."
Professor Thomas B. Mack
Professor Thomas B. Mack was an avid collector of information on citrus. As he wrote hundreds of articles on citrus, more and more people contributed to his store of information. In 1988, Florida Southern College devoted a special room in the Jack Berry Citrus Building to Professor Mack's collection, and an archivist to manage it. His intent was to create an open source of information for the citrus industry.
In 1997, Professor Mack was inducted to the Florida Citrus Hall of Fame as "an integral member of Florida's Citrus community for over half a century." Professor Mack wrote a column called "Citrifacts" on various citrus-related trivia that earned him the nickname "Mr. Citrifacts." His columns were eventually compiled into the books "Citrifacts I" and "Citrifacts II," with the proceeds from sales going to benefit Florida Southern College. |
https://en.wikipedia.org/wiki/KeyKOS | KeyKOS is a persistent, pure capability-based operating system for the IBM S/370 mainframe computers. It allows emulating the environments of VM, MVS, and Portable Operating System Interface (POSIX). It is a predecessor of the Extremely Reliable Operating System (EROS), and its successor operating systems, CapROS, and Coyotos. KeyKOS is a nanokernel-based operating system.
In the mid-1970s, development of KeyKOS began at Tymshare, Inc., under the name GNOSIS. In 1984, McDonnell Douglas (MD) bought Tymshare. A year later MD spun off Key Logic, which bought GNOSIS and renamed it KeyKOS. |
https://en.wikipedia.org/wiki/DECpc | DECpc was a wide-ranging family of desktop computers, laptops, servers, and workstations sold by Digital Equipment Corporation. The vast majority in the family are based on x86 processors, although the APX 150 uses DEC's own Alpha processor. The line was DEC's first big break into the IBM PC compatible market.
Some entries in the desktop DECpc range were built by Olivetti S.p.A. and Tandy Corporation.
Line-up
Explanatory notes
Upgradable with snap-in processor/cache daughtercard
Advanced Power Management–compliant
Desktops
Laptops
Workstations and servers
See also
Digital HiNote, the successor to the DECpc line of laptops
DECstation, concurrent line of workstations |
https://en.wikipedia.org/wiki/Graphic%20charter%20of%20government%20communication%20in%20France | The graphic charter of government communication is the graphic charter of the logo of France, used by government services. It was adopted in 1999 by the government of Lionel Jospin and revolves around a logo associating Marianne, the tricolour flag and the motto Liberté, Égalité, Fraternité () to represent the French Republic. A redesign of this graphic charter was carried out in 2020.
History
François Mitterrand, when he was the President of the Republic, was offered by Jacques Séguéla the idea of a logo for state institutions. However, he had refused it, deeming it too publicity.
In 1997, the Court of Auditors noted in a report that a “kaleidoscope of different symbols” existed in the publications of the administration. Its author, Bernard Candiard, who then became director of the Service d'information du Gouvernement (SIG or ), launched the project of creating a logo within this organization, with Nicole Civatte. The objective was to "create an identifier of the State which would clearly indicate that the State exists as a specific issuer: a place where an autonomous word has to be affirmed", according to an internal document issued in March 1999 by SIG.
A call for tenders was launched in 1998, the first example of the State outsourcing its visual communication. The creation of the logo was entrusted to the Audour Soum agency (which then merged with the Hémisphère droit agency, a subsidiary of the Séguéla group), with Evelyn Soum as project manager. Designed by graphic designer Isabelle Bauret, the logo met specifications drawn up "at the end of an investigation combining semiotic analysis, interviews with senior officials, as well as meetings with the general public". It was tested by Sofres to the public and government officials before being released. But the President of the Republic, Jacques Chirac, consulted by the government in January 1999, hesitating at first to "touch the integrity of the flag".
The graphic charter was finally introduced by circular |
https://en.wikipedia.org/wiki/Hyrachyus | Hyrachyus (from Hyrax and "pig") is an extinct genus of perissodactyl mammal that lived in Eocene Europe, North America, and Asia. Its remains have also been found in Jamaica. It is closely related to Lophiodon.
Description
The 1.5-m-long beast was related to palaeotheres, and suspected to be the ancestor of modern tapirs and rhinoceroses. Physically, it would have looked very similar to modern tapirs, although it probably lacked the tapir's characteristic proboscis. Its teeth, however, resembled those of a rhinoceros, supporting the idea of its relationship with that group. |
https://en.wikipedia.org/wiki/Jur%20Hronec | Jur Hronec (May 17, 1881; Gočovo, Rožňava District – December 1, 1959; Bratislava) was a Slovak mathematician.
Early years
Jur Hronec was born in Gočovo, Slovakia (then Gócs, Kingdom of Hungary). He grew up in modest circumstances in a farmers family. After graduating from high school in Rožňava he studied mathematics and physics at the University of Kolozsvár under supervision of Professor Ludwig Schlesinger. From 1908 to 1914 he studied at Göttingen, Giessen, Berlin, Switzerland and Paris, in the years 1922–1923 in Prague, Göttingen and Giessen. His doctoral dissertation in the field of differential equations was defended in 1912 in Giessen.
Career
In years 1906–1922, after successful completion of the university, he worked in years with fewer interruptions while on study abroad at school in Kezmarok.
Jur Hronec was habilitated at Charles University in Prague in 1923. From 1924 to 1939 he was professor of mathematics at the Czech Technical University in Brno. Educational work of the school determined his further scientific focus. He recognised the importance of mathematics in science and technology and focused his research on application to technical problems. His academic lifetime achievement includes three areas: scientific, educational and public. Research activities focused primarily on differential equations. He studied problems of Erdős–Fuchs theorem of linear differential equations and their generalisation.
He wrote a considerable number of scientific papers, publications and university textbooks, the most important are:
Algebraic equations and their use in analytical geometry (1923, 1949)
Linear ordinary differential equations (1938)
The differential and integral calculus I, II (1941, 1957) - first Slovak university textbook of mathematics
Differential Equations I, II (1956–1958) and many scientific papers published in journals.
He lectured at many national and international conferences and symposia. Throughout his scientific and pedagogical |
https://en.wikipedia.org/wiki/Starred%20transform | In applied mathematics, the starred transform, or star transform, is a discrete-time variation of the Laplace transform, so-named because of the asterisk or "star" in the customary notation of the sampled signals.
The transform is an operator of a continuous-time function , which is transformed to a function in the following manner:
where is a Dirac comb function, with period of time T.
The starred transform is a convenient mathematical abstraction that represents the Laplace transform of an impulse sampled function , which is the output of an ideal sampler, whose input is a continuous function, .
The starred transform is similar to the Z transform, with a simple change of variables, where the starred transform is explicitly declared in terms of the sampling period (T), while the Z transform is performed on a discrete signal and is independent of the sampling period. This makes the starred transform a de-normalized version of the one-sided Z-transform, as it restores the dependence on sampling parameter T.
Relation to Laplace transform
Since , where:
Then per the convolution theorem, the starred transform is equivalent to the complex convolution of and , hence:
This line integration is equivalent to integration in the positive sense along a closed contour formed by such a line and an infinite semicircle that encloses the poles of X(s) in the left half-plane of p. The result of such an integration (per the residue theorem) would be:
Alternatively, the aforementioned line integration is equivalent to integration in the negative sense along a closed contour formed by such a line and an infinite semicircle that encloses the infinite poles of in the right half-plane of p. The result of such an integration would be:
Relation to Z transform
Given a Z-transform, X(z), the corresponding starred transform is a simple substitution:
This substitution restores the dependence on T.
It's interchangeable,
Properties of the starred transform
Property 1: i |
https://en.wikipedia.org/wiki/Gas%20exchange | Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.
Gases are constantly consumed and produced by cellular and metabolic reactions in most living things, so an efficient system for gas exchange between, ultimately, the interior of the cell(s) and the external environment is required. Small, particularly unicellular organisms, such as bacteria and protozoa, have a high surface-area to volume ratio. In these creatures the gas exchange membrane is typically the cell membrane. Some small multicellular organisms, such as flatworms, are also able to perform sufficient gas exchange across the skin or cuticle that surrounds their bodies. However, in most larger organisms, which have small surface-area to volume ratios, specialised structures with convoluted surfaces such as gills, pulmonary alveoli and spongy mesophylls provide the large area needed for effective gas exchange. These convoluted surfaces may sometimes be internalised into the body of the organism. This is the case with the alveoli, which form the inner surface of the mammalian lung, the spongy mesophyll, which is found inside the leaves of some kinds of plant, or the gills of those molluscs that have them, which are found in the mantle cavity.
In aerobic organisms, gas exchange is particularly important for respiration, which involves the uptake of oxygen () and release of carbon dioxide (). Conversely, in oxygenic photosynthetic organisms such as most land plants, uptake of carbon dioxide and release of both oxygen and water vapour are the main gas-exchange processes occurring during the day. Other gas-exchange processes are important in less familiar organisms: e.g. carbon dioxide, methane and hydrogen are exchanged a |
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