source
stringlengths 31
203
| text
stringlengths 28
2k
|
|---|---|
https://en.wikipedia.org/wiki/Degustation
|
Dégustation is the careful, appreciative tasting of various food, focusing on the gustatory system, the senses, high culinary art and good company. Dégustation is more likely to involve sampling small portions of all of a chef's signature dishes in one sitting. Usually consisting of many courses, it may be accompanied by a matching wine degustation which complements each dish.
History
The French term dégustation is still commonly used in English-language contexts. Modern dégustation probably comes from the French kitchens of the early 20th century and is different from earlier meals with many courses because these meals were served as full-sized meals at each course.
Examples
Sampling a selection of cheeses, at home or in a restaurant, may also be called a dégustation. Three to four varieties are normally chosen, generally including a semi-soft cheese, a goat's cheese, and a blue cheese. The stronger varieties are normally tasted last.
A six course dégustation may include two seafood, red meat and dessert items with matching wines while the same menu could have added a vegetarian item, and any other types of dish to expand the menu to (for example) a nine-course dégustation menu.
The popular Spanish style of tapas is similar to the dégustation style, but is not in itself a complete set menu offering the chefs' signature dishes, but instead offers a variety from which the diner can choose.
See also
Tasting menu
Formal dinner
Wine tasting
References
French cuisine
Gustation
Eating parties
Culinary terminology
|
https://en.wikipedia.org/wiki/SAFARI
|
SAFARI was an attempt by the French government, under the presidency of Georges Pompidou, to create a centralized database of personal data. SAFARI stands for Système Automatisé pour les Fichiers Administratifs et le Répertoire des Individus, "Automated System for Administrative Files and the Repertory of Individuals".
History
The first mention of the project was made in a three-page article in the INSEE central review in March 1970. The French government began secretly working on the SAFARI project in 1973. The project aimed to identify French citizens with a unique number that would connect the information about them from various databases. In particular, it would use the INSEE code (also used as a Social Security number). The system was to be based on the Iris-80 computer.
On March 21, 1974, an article in the newspaper Le Monde by journalist Philippe Boucher revealed the existence of the project. The public outcry was immense, some critics comparing it to the national identity database created by the Vichy regime during Nazi occupation. The massive popular rejection of SAFARI prompted the minister of justice to create the Commission on Data Processing and Freedom, also known as the Tricot Commission after its leader Bernard Tricot. This led to the creation of the CNIL to ensure data privacy, as well as an accompanying 1978 law, the Data Protection and Liberties Act, restricting the storage and processing of personal data.
References
See also
Government databases
French political scandals
Law enforcement in France
Information privacy
Government databases in France
Privacy in France
|
https://en.wikipedia.org/wiki/Coastal%20management
|
Coastal management is defence against flooding and erosion, and techniques that stop erosion to claim lands. Protection against rising sea levels in the 21st century is crucial, as sea level rise accelerates due to climate change. Changes in sea level damage beaches and coastal systems are expected to rise at an increasing rate, causing coastal sediments to be disturbed by tidal energy.
Coastal zones occupy less than 15% of the Earth's land area, while they host more than 40% of the world population. Nearly 1.2 billion people live within 100 km of shoreline and 100 m of sea level, with an average density 3 times higher than the global average for population. With three-quarters of the world population expected to reside in the coastal zone by 2025, human activities originating from this small land area will impose heavy pressure on coasts. Coastal zones contain rich resources to produce goods and services and are home to most commercial and industrial activities.
History
Coastal engineering of harbours began with the origin of maritime traffic, perhaps before 3500 B.C. Docks, breakwaters and other harbour works were built by hand, often in a grand scale.
The Romans introduced many innovations in harbour design. They built walls underwater and constructed solid breakwaters. These structures were made using Roman concrete. Vitruvius described three methods for building port structures (De Architectura, 5, 12). Other types of port structure such as rubble mounds and arched breakwaters built by means of timber floating caissons were used also.
Romans were the first dredgers in the Netherlands to maintain the harbour at Velsen. Silting problems there were solved when the previously sealed solid piers were replaced with new "open"-piled jetties.
Ancient harbour works are still visible, but most of them disappeared following the fall of the Western Roman Empire even if submerged remains are sometimes still visible under water.
Although most coastal efforts were directe
|
https://en.wikipedia.org/wiki/Markman%20v.%20Westview%20Instruments%2C%20Inc.
|
Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996), is a United States Supreme Court case on whether the interpretation of patent claims is a matter of law or a question of fact. An issue designated as a matter of law is resolved by the judge, and an issue construed as a question of fact is determined by the jury.
Background
Herbert Markman patented a system to track clothes through the dry cleaning process using barcode to generate receipts and track inventory.
The 7th Amendment guarantees the right to a jury trial in patent infringement cases. The 7th Amendment preserves the right to a jury trial as it existed in 1791. There is no dispute that infringement cases today must be tried by a jury as their predecessors were in 1791. However, the court held that the construction of the patent, including the terms of art within its claim, is exclusively within the court's province.
In general, the effectiveness of a particular patent depends on its potential to block competitors. The key for a patent holder is getting the proper definition of words used in the patent to allow blocking of the particular troublesome competitive product. Before this decision, juries were responsible for deciding the meaning of the words used in patent claims. Opposing results in cases with similar facts were common, and a perception arose that the outcome of such trials was somewhat arbitrary. In Markman, the Court held that judges, not juries, would evaluate and decide the meaning of the words used in patent claims. Judges were to look at four sources for definitions, in order of priority:
the written description accompanying the patent claims is most relevant;
the documentation of the history of the patent as it went through the application;
standard dictionaries of English;
finally, if all else fails, expert testimony from experts "skilled in the art" at issue.
This case has had a significant impact on the patent litigation process in the United States. Many jurisdict
|
https://en.wikipedia.org/wiki/Speech%20Application%20Language%20Tags
|
Speech Application Language Tags (SALT) is an XML-based markup language that is used in HTML and XHTML pages to add voice recognition capabilities to web-based applications.
Description
Speech Application Language Tags enables multimodal and telephony-enabled access to information, applications, and Web services from PCs, telephones, tablet PCs, and wireless personal digital assistants (PDAs). The Speech Application Language Tags extend existing mark-up languages such as HTML, XHTML, and XML. Multimodal access will enable users to interact with an application in a variety of ways: they will be able to input data using speech, a keyboard, keypad, mouse and/or stylus, and produce data as synthesized speech, audio, plain text, motion video, and/or graphics.
History
SALT was developed as a competitor to VoiceXML and was supported by the SALT Forum. The SALT Forum was founded on October 15, 2001, by Microsoft, along with Cisco Systems, Comverse, Intel, Philips Consumer Electronics, and ScanSoft. The SALT 1.0 specification was submitted to the W3C (World Wide Web Consortium) for review in August 2002. However, the W3C continued developing its VoiceXML 2.0 standard, which reached the final "Recommendation" stage in March 2004.
By 2006, Microsoft realized Speech Server had to support the W3C VoiceXML standard to remain competitive. Microsoft joined the VoiceXML Forum as a Promoter in April of that year. Speech Server 2007 supports VoiceXML 2.0 and 2.1 in addition to SALT. In 2007, Microsoft purchased Tellme, one of the largest VoiceXML service providers.
By that point nearly every other SALT Forum company had committed to VoiceXML. The last press release posted to the SALT Forum website was in 2003, while the VoiceXML Forum is quite active. "SALT [Speech Application Language Tags] is a direct competitor but has not reached the level of maturity of VoiceXML in the standards process," said Bill Meisel, principal at TMA Associates, a speech technology research firm.
Us
|
https://en.wikipedia.org/wiki/Tank%20Battalion
|
is a multi-directional shooter arcade video game that was released by Namco in 1980. The only direct home conversion is for the MSX, although it was followed up by two sequels: Battle City for the Famicom in 1985 and Tank Force for arcades in 1991.
Gameplay
The player, controlling a tank, must destroy twenty enemy tanks in each round, which enter the playfield from the top of the screen. The enemy tanks attempt to destroy the player's base (represented on the map as an eagle) as well as the player tank itself. A round is cleared when the player destroys all twenty enemy tanks, but the game ends if the player's base is destroyed or they run out of lives.
Reception
Cash Box believed that "the real excitement" of Tank Battalion lied within its ability to modify the level design by destroying the brick walls.
Retrospectively in 2015, a writer for Beep! enjoyed the Sord M5 version for its improvements over the arcade original, such as the smoother movement of the player's tank, but disliked the squashed-looking graphics and narrow playing space. While the writer believed the MSX version was superior, they still recommended the M5 version for Namco fans and collectors.
Legacy
A theme based on the game for Pac-Man 99 was released as free post-launch DLC, featuring visuals and sounds from the game.
Notes
References
External links
1980 video games
Arcade video games
Bandai Namco Entertainment franchises
Multidirectional shooters
Namco arcade games
MSX games
Tank simulation video games
Video games developed in Japan
|
https://en.wikipedia.org/wiki/Gap%20analysis
|
In management literature, gap analysis involves the comparison of actual performance with potential or desired performance. If an organization does not make the best use of current resources, or forgoes investment in capital or technology, it may produce or perform below an idealized potential. This concept is similar to an economy's production being below the production possibilities frontier.
Gap analysis identifies gaps between the optimized allocation and integration of the inputs (resources), and the current allocation-level. This reveals areas that can be improved. Gap analysis involves determining, documenting and improving the difference between business requirements and current capabilities. Gap analysis naturally flows from benchmarking and from other assessments. Once the general expectation of performance in an industry is understood, it is possible to compare that expectation with the company's current level of performance. This comparison becomes the gap analysis. Such analysis can be performed at the strategic or at the operational level of an organization.
Gap analysis is a formal study of what a business is doing currently and where it wants to go in the future. It can be conducted, in different perspectives, as follows:
Organization (e.g., Human Resources)
Business direction
Business processes
Information technology
Gap analysis provides a foundation for measuring investment of time, money and human resources required to achieve a particular outcome (e.g. to turn the salary payment process from paper-based to paperless with the use of a system). Note that "GAP analysis" has also been used as a means of classifying how well a product or solution meets a targeted need or set of requirements. In this case, "GAP" can be used as a ranking of "Good", "Average" or "Poor". (This terminology appears in the PRINCE2 project management publication.)
Gap analysis and new products
The need for new products or additions to existing lines may emerge from
|
https://en.wikipedia.org/wiki/GameStorm
|
GameStorm was an online gaming service founded by Kesmai corporation in November 1997. It offered several online video games at a flat monthly fee of $10 per month, a relatively radical payment system in the age of pay-by-hour online gaming. Both Kesmai and GameStorm were sold to Electronic Arts in 1999, and shut down by Electronic Arts in 2001.
GameStorm featured games developed by Kesmai, such as Air Warrior, Multiplayer Battletech: Solaris, Stellar Emperor and Legends of Kesmai, along with games developed by several other companies. Legends of Kesmai was the 2d graphical version of Kesmai's groundbreaking Islands of Kesmai MUD from 1985, and may be regarded as an important step in the genre leap from MUDs to MMORPGs. GameStorm's payment method was massively popular for the emerging persistent online gaming genres that rewarded players for time invested, but were too expensive for many people to pay $2/hour for on AOL or other gaming services. Mythic Entertainment (Now EA-Mythic), widely known for the Dark Age of Camelot MMORPG, was one of Gamestorms major developers. Mythic offered several licensed RPG and persistent non-RPG games to Gamestorm's library, including Dragon's Gate. Starship Troopers Online, Magestorm, Aliens Online, Splatterball, Godzilla Online, Silent Death Online, Darkness Falls, and Darkness Falls: The Crusade.
References
External links
The MultiPlayer BattleTech Archive
http://www.thecomputershow.com/computershow/interviews/legendsofkesmai.htm
http://angelsofwrath.net
http://www.legendsofkesmai.com
Online video game services
Video game publishers
|
https://en.wikipedia.org/wiki/Wool%20bale
|
A wool bale is a standard sized and weighted pack of classed wool compressed by the mechanical means of a wool press. This is the regulation required method of packaging for wool, to keep it uncontaminated and readily identifiable. A "bale of wool" is also the standard trading unit for wool on the wholesale national and international markets.
The minimum weight of a bale is .
Wool packs
Packaging of wool has not changed much for centuries except that the early wool packs were made from jute, prior to the use of synthetic fibres. Jute packs were relatively heavy, weighing several kilograms each. In the 1960s polypropylene and high-density polyethylene packs were manufactured and used to make wool bales. Loose fibres from these packs caused contamination of the wool in the bale and led to nylon becoming the regulation fabric used in Australia. In South Africa woven paper was tested but discontinued in 1973 due to poor wet strength and high cost. Regulation standard white nylon packs now have a label sewn onto the top flap of the wool pack for inclusion of the farm brand, wool description, bale number, woolclasser stencil number and bin code. Each bale of wool packs contains 50 packs that measure x and have flaps.
History
Very early wool presses were made from wood boards and had a wire winch mechanism to compress the wool and also hollow logs where the wool was tramped into a pack. During the late 19th century various forms of wooden wool press became the standard. Most popular models were the Koerstz and the Ferrier. The Koerstz was a smaller press than the Ferrier. The Ferrier press was manufactured under license by Humble & Nicholson (later Humble & Sons), Geelong, Victoria, and they had sold 2,000 presses between about 1871 and 1918. These presses were distributed throughout Australia, but were also sent overseas to New Zealand, South America, and North Africa. The most popular wool press in New Zealand was the Donalds Wool Press which was manufactured
|
https://en.wikipedia.org/wiki/EIA-530
|
Currently known as TIA-530-A, but often called EIA-530, or RS-530, is a balanced serial interface standard that generally uses a 25-pin connector, originally created by the Telecommunications Industry Association.
Finalized in 1987 (revision A finalized in 1992), the specification defines the cable between the DTE and DCE devices. It is to be used in conjunction with EIA-422 and EIA-423, which define the electrical signaling characteristics. Because TIA-530 calls for the more common 25 pin connector, it displaced the similar EIA-449, which also uses EIA-422/423, but a larger 37-pin connector.
Two types of interchange circuits ("signals" or "leads") between the DCE and DTE are defined in TIA-530: Category I, which uses the balanced characteristics of EIA-422, and Category II, which is the unbalanced EIA-423. Most of the interchange circuits are Category I, with the exception of Local Loopback (pin 18), Remote Loopback (pin 21), and Test Mode (pin 25) being Category II.
TIA-530 originally used Category I circuits for what is commonly called "Data Set Ready" (DCE Ready, pins 6 and 22) and "Data Terminal Ready" (DTE Ready, pins 20 and 23). Revision A changed these interchange circuits to Category II (para 4.3.6 and 4.3.7 of the standard) and added a "Ring Indicator" on pin 22. Pin 23 is grounded in TIA-530-A.
Confusion between the revisions has led to many incorrect wiring diagrams of this interface and most manufacturers still adhere to the original TIA-530 standard. Care should be taken to ensure devices are of the same standard before connecting to avoid complications.
Make note that the diagram shows pin 24 being "B" when it is actually "A".
References
Serial buses
Physical layer protocols
|
https://en.wikipedia.org/wiki/Nastic%20movements
|
In biology, nastic movements are non-directional responses to stimuli (e.g. temperature, humidity, light irradiance), and are usually associated with plants. The movement can be due to changes in turgor (internal pressure within plant cells). Decrease in turgor pressure causes shrinkage, while increase in turgor pressure brings about swelling. Nastic movements differ from tropic movements in that the direction of tropic responses depends on the direction of the stimulus, whereas the direction of nastic movements is independent of the stimulus's position. The tropic movement is growth movement but nastic movement may or may not be growth movement. The rate or frequency of these responses increases as intensity of the stimulus increases. An example of such a response is the opening and closing of flowers (photonastic response), movement of euglena, chlamydomonas towards the source of light . They are named with the suffix "-nasty" and have prefixes that depend on the stimuli:
Epinasty: downward-bending from growth at the top, for example, the bending down of a heavy flower.
Hyponasty: upward bending of leaves from growth in the petiole (leaf stalk)
Photonasty: response to light
Nyctinasty: movements at night or in the dark
Chemonasty: response to chemicals or nutrients
Hydronasty: response to water
Thermonasty: response to temperature
Seismonasty: response to shock
Geonasty/gravinasty: response to gravity
Thigmonasty/seismonasty/haptonasty: response to contact
The suffix may come from Greek νάσσω = "I press", ναστός = "pressed", ἐπιναστια = "the condition of being pressed upon".
See also
For other types of movement, see:
Taxis
Tropism
Kinesis
References
External links
'Daisy - 'Day's Eye or Eye of the Day'.
Physiology
Articles containing video clips
de:Pflanzenbewegung#Nastien und Tropismen
|
https://en.wikipedia.org/wiki/XMLVend
|
XMLVend is a South African developed, open interface standard, which facilitates the sale of prepaid electricity credit between electricity utilities and clients. It is an application of web services to facilitate trade between various types of devices and a utility prepayment vending server.
This standard is already being introduced and used in prepaid water.
External links
Eskom XMLVend implementation website
Eskom Technical Documents
Eskom Prepayment
Johannesburg Water
Web services
|
https://en.wikipedia.org/wiki/Cauchy%27s%20theorem%20%28group%20theory%29
|
In mathematics, specifically group theory, Cauchy's theorem states that if is a finite group and is a prime number dividing the order of (the number of elements in ), then contains an element of order . That is, there is in such that is the smallest positive integer with = , where is the identity element of . It is named after Augustin-Louis Cauchy, who discovered it in 1845.
The theorem is related to Lagrange's theorem, which states that the order of any subgroup of a finite group divides the order of . Cauchy's theorem implies that for any prime divisor of the order of , there is a subgroup of whose order is —the cyclic group generated by the element in Cauchy's theorem.
Cauchy's theorem is generalized by Sylow's first theorem, which implies that if is the maximal power of dividing the order of , then has a subgroup of order (and using the fact that a -group is solvable, one can show that has subgroups of order for any less than or equal to ).
Statement and proof
Many texts prove the theorem with the use of strong induction and the class equation, though considerably less machinery is required to prove the theorem in the abelian case. One can also invoke group actions for the proof.
Proof 1
We first prove the special case that where is abelian, and then the general case; both proofs are by induction on = ||, and have as starting case = which is trivial because any non-identity element now has order . Suppose first that is abelian. Take any non-identity element , and let be the cyclic group it generates. If divides ||, then ||/ is an element of order . If does not divide ||, then it divides the order [:] of the quotient group /, which therefore contains an element of order by the inductive hypothesis. That element is a class for some in , and if is the order of in , then = in gives () = in /, so divides ; as before / is now an element of order in , completing the proof for the abelian case.
In the general case, let be th
|
https://en.wikipedia.org/wiki/Muda%20%28Japanese%20term%29
|
is a Japanese word meaning "futility", "uselessness", or "wastefulness", and is a key concept in lean process thinking such as in the Toyota Production System (TPS), denoting one of three types of deviation from optimal allocation of resources. The other types are known by the Japanese terms mura ("unevenness") and muri ("overload"). Waste in this context refers to the wasting of time or resources rather than wasteful by-products and should not be confused with Waste reduction.
From an end-customer's point of view, value-added work is any activity that produces goods or provides a service for which a customer is willing to pay; muda is any constraint or impediment that causes waste to occur.
There are two types of muda:
Muda Type I: non value-adding, but necessary for end-customers. These are usually harder to eliminate because while classified as non-value adding, they may still be necessary.
Muda Type II: non value-adding and unnecessary for end-customers. These contribute to waste, incur hidden costs and should be eliminated.
Toyota's (Ohno's) Seven Forms of Waste
One of the key steps in lean process and TPS is to identify which activities add value and which do not, then to progressively work to improve or eliminate them.
Taiichi Ohno, "father" of the Toyota Production System, originally identified seven forms of muda or waste:
A mnemonic may be useful for remembering the categories of waste, such as TIM WOOD or TIM WOODS.
Transportation
Every time a product is touched or moved unnecessarily there is a risk that it could be damaged, lost, delayed, etc. as well as being a cost for no added value. Transportation does not add value to the product, i.e. is not a transformation for which the consumer is willing to pay.
Inventory
Whether in the form of raw materials, work-in-progress (WIP), or finished goods, represents a capital outlay that cannot yet produce an income. The longer a product sits in one of these states, the more it contributes to waste. The
|
https://en.wikipedia.org/wiki/Calculus%20on%20Manifolds%20%28book%29
|
Calculus on Manifolds: A Modern Approach to Classical Theorems of Advanced Calculus (1965) by Michael Spivak is a brief, rigorous, and modern textbook of multivariable calculus, differential forms, and integration on manifolds for advanced undergraduates.
Description
Calculus on Manifolds is a brief monograph on the theory of vector-valued functions of several real variables (f : Rn→Rm) and differentiable manifolds in Euclidean space. In addition to extending the concepts of differentiation (including the inverse and implicit function theorems) and Riemann integration (including Fubini's theorem) to functions of several variables, the book treats the classical theorems of vector calculus, including those of Cauchy–Green, Ostrogradsky–Gauss (divergence theorem), and Kelvin–Stokes, in the language of differential forms on differentiable manifolds embedded in Euclidean space, and as corollaries of the generalized Stokes theorem on manifolds-with-boundary. The book culminates with the statement and proof of this vast and abstract modern generalization of several classical results:
The cover of Calculus on Manifolds features snippets of a July 2, 1850 letter from Lord Kelvin to Sir George Stokes containing the first disclosure of the classical Stokes' theorem (i.e., the Kelvin–Stokes theorem).
Reception
Calculus on Manifolds aims to present the topics of multivariable and vector calculus in the manner in which they are seen by a modern working mathematician, yet simply and selectively enough to be understood by undergraduate students whose previous coursework in mathematics comprises only one-variable calculus and introductory linear algebra. While Spivak's elementary treatment of modern mathematical tools is broadly successful—and this approach has made Calculus on Manifolds a standard introduction to the rigorous theory of multivariable calculus—the text is also well known for its laconic style, lack of motivating examples, and frequent omission of non-obvious ste
|
https://en.wikipedia.org/wiki/Megadiverse%20countries
|
A megadiverse country is one of a group of nations that harbours the majority of Earth's species and high numbers of endemic species. Conservation International identified 17 megadiverse countries in 1998. Many of them are located at least partially in tropical or subtropical regions.
Megadiversity means exhibiting great biodiversity. The main criterion for megadiverse countries is endemism at the level of species, genera and families. A megadiverse country must have at least 5,000 species of endemic plants and must border marine ecosystems.
In 2002, Mexico formed a separate organization focusing on Like-Minded Megadiverse Countries, consisting of countries rich in biological diversity and associated traditional knowledge. This organization includes all but three megadiverse countries as identified by Conservation International.
List of megadiverse countries
In alphabetical order, the 17 megadiverse countries are:
List of most biodiverse countries 2022
Cancún initiative and declaration of like-minded megadiverse countries
On 18 February 2002, the Ministers in charge of the Environment and the Delegates of Brazil, China, Colombia, Costa Rica, India, Indonesia, Kenya, Mexico, Peru, the Philippines, South Africa and Venezuela assembled in Cancún, Mexico. These countries declared to set up a Group of Like-Minded Megadiverse Countries as a mechanism for consultation and cooperation so that their interests and priorities, related to the preservation and sustainable use of biological diversity, could be promoted. They also declared that they would call on those countries that had not become Parties to the Convention on Biological Diversity, the Cartagena Protocol on Biosafety, and the Kyoto Protocol on climate change to become parties to these agreements.
At the same time, they agreed to meet periodically, at the ministerial and expert levels, and decided that upon the conclusion of each annual Ministerial Meeting, the next rotating host country would take on the r
|
https://en.wikipedia.org/wiki/Flora%20%28microbiology%29
|
In microbiology, collective bacteria and other microorganisms in a host are historically known as flora. Although microflora is commonly used, the term microbiota is becoming more common as microflora is a misnomer. Flora pertains to the Kingdom Plantae. Microbiota includes Archaea, Bacteria, Fungi and Protists. Microbiota with animal-like characteristics can be classified as microfauna.
History
The terms "Flora" and "Fauna" were first used by Carl Linnaeus from Sweden in the title of his 1745 work Flora Suecica and Fauna Suecica. At that time, biology was focused on macroorganisms. Later, with the advent of microscopy, the new discovered ubiquitous microorganisms were fit in this system. Then, Fauna included moving organisms (animals and protist as "micro-fauna") and Flora the organisms with apparent no movement (plants/fungi; and bacteria as "microflora"). The terms "microfauna" and "microflora" are common in old books, but recently they have been replaced by the more adequate term "microbiota". Microbiota includes Archaea, Bacteria, Fungi and Protists.
Microflora classification
Microflora are grouped into two categories based on the origin of the microorganism.
Autochthonous flora. - Bacteria and microorganisms native to the host environment
Allochthonous flora. - Temporary microorganisms non-native to the host environment
Roles
Microflora is a term that refers to a community of bacteria that exist on or inside the body, and possess a unique ecological relationship with the host. This relationship encompasses a wide variety of microorganisms and the interactions between microbes. These interactions are often a mutualistic relationships between the host and autochthonous flora. Microflora responsible for harmful diseases are often allochthonous flora.
The modern term is "Microbiome" and include microorganisms that have different roles in ecosystems or hosts, including free-living organisms, or organisms associated to hosts, such animals (including humans)
|
https://en.wikipedia.org/wiki/Output%20compare
|
Output compare is the ability to trigger an output based on a timestamp in memory, without interrupting the execution of code by a processor or microcontroller. This is a functionality provided by many embedded systems.
The corresponding ability to record a timestamp in memory when an input occurs is called input capture.
Embedded systems
Microchip Documentation on Output Compare: DS39706A-page 16-1 - Section 16. Output Compare http://ww1.microchip.com/downloads/en/DeviceDoc/39706a.pdf
|
https://en.wikipedia.org/wiki/Generic%20Array%20Logic
|
The Generic Array Logic (also known as GAL and sometimes as gate array logic) device was an innovation of the PAL and was invented by Lattice Semiconductor. The GAL was an improvement on the PAL because one device type was able to take the place of many PAL device types or could even have functionality not covered by the original range of PAL devices. Its primary benefit, however, was that it was erasable and re-programmable, making prototyping and design changes easier for engineers.
A similar device called a PEEL (programmable electrically erasable logic) was introduced by the International CMOS Technology (ICT) corporation.
See also
Programmable logic device (PLD)
Complex programmable logic device (CPLD)
Erasable programmable logic device (EPLD)
GAL22V10
References
Further reading
PEEL Software and Applications Handbook; International CMOS Technology (ICT); 138 pages; 1989. (archive)
Electronic design automation
Gate arrays
|
https://en.wikipedia.org/wiki/Television%20station
|
A television station is a set of equipment managed by a business, organisation or other entity such as an amateur television (ATV) operator, that transmits video content and audio content via radio waves directly from a transmitter on the earth's surface to any number of tuned receivers simultaneously.
Overview
Most often the term "television station" refers to a station which broadcasts structured content to an audience or it refers to the organization that operates the station. A terrestrial television transmission can occur via analog television signals or, more recently, via digital television signals. Television stations are differentiated from cable television or other video providers as their content is broadcast via terrestrial radio waves. A group of television stations with common ownership or affiliation are known as a TV network and an individual station within the network is referred to as O&O or affiliate, respectively.
Because television station signals use the electromagnetic spectrum, which in the past has been a common, scarce resource, governments often claim authority to regulate them. Broadcast television systems standards vary around the world. Television stations broadcasting over an analog system were typically limited to one television channel, but digital television enables broadcasting via subchannels as well. Television stations usually require a broadcast license from a government agency which sets the requirements and limitations on the station. In the United States, for example, a television license defines the broadcast range, or geographic area, that the station is limited to, allocates the broadcast frequency of the radio spectrum for that station's transmissions, sets limits on what types of television programs can be programmed for broadcast and requires a station to broadcast a minimum amount of certain programs types, such as public affairs messages.
Another form of television station is non-commercial educational (NCE) and
|
https://en.wikipedia.org/wiki/Adaptive%20software%20development
|
Adaptive software development (ASD) is a software development process that grew out of the work by Jim Highsmith and Sam Bayer on rapid application development (RAD). It embodies the principle that continuous adaptation of the process to the work at hand is the normal state of affairs.
Adaptive software development replaces the traditional waterfall cycle with a repeating series of speculate, collaborate, and learn cycles. This dynamic cycle provides for continuous learning and adaptation to the emergent state of the project. The characteristics of an ASD life cycle are that it is mission focused, feature based, iterative, timeboxed, risk driven, and change tolerant. As with RAD, ASD is also an antecedent to agile software development.
The word speculate refers to the paradox of planning – it is more likely to assume that all stakeholders are comparably wrong for certain aspects of the project’s mission, while trying to define it. During speculation, the project is initiated and adaptive cycle planning is conducted.
Adaptive cycle planning uses project initiation information—the customer’s
mission statement, project constraints (e.g., delivery dates or user descriptions), and
basic requirements—to define the set of release cycles (software increments) that
will be required for the project.
Collaboration refers to the efforts for balancing the work based on predictable parts of the environment (planning and guiding them) and adapting to the uncertain surrounding mix of changes caused by various factors, such as technology, requirements, stakeholders, software vendors. The learning cycles, challenging all stakeholders, are based on the short iterations with design, build and testing. During these iterations the knowledge is gathered by making small mistakes based on false assumptions and correcting those mistakes, thus leading to greater experience and eventually mastery in the problem domain.
References
Adaptive Software Development: A Collaborative Approach to
|
https://en.wikipedia.org/wiki/Locus%20%28genetics%29
|
In genetics, a locus (: loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located. Each chromosome carries many genes, with each gene occupying a different position or locus; in humans, the total number of protein-coding genes in a complete haploid set of 23 chromosomes is estimated at 19,000–20,000.
Genes may possess multiple variants known as alleles, and an allele may also be said to reside at a particular locus. Diploid and polyploid cells whose chromosomes have the same allele at a given locus are called homozygous with respect to that locus, while those that have different alleles at a given locus are called heterozygous. The ordered list of loci known for a particular genome is called a gene map. Gene mapping is the process of determining the specific locus or loci responsible for producing a particular phenotype or biological trait. Association mapping, also known as "linkage disequilibrium mapping", is a method of mapping quantitative trait loci (QTLs) that takes advantage of historic linkage disequilibrium to link phenotypes (observable characteristics) to genotypes (the genetic constitution of organisms), uncovering genetic associations.
Nomenclature
The shorter arm of a chromosome is termed the p arm or p-arm, while the longer arm is the q arm or q-arm. The chromosomal locus of a typical gene, for example, might be written 3p22.1, where:
3 = chromosome 3
p = p-arm
22 = region 2, band 2 (read as "two, two", not "twenty-two")
1 = sub-band 1
Thus the entire locus of the example above would be read as "three P two two point one". The cytogenetic bands are areas of the chromosome either rich in actively-transcribed DNA (euchromatin) or packaged DNA (heterochromatin). They appear differently upon staining (for example, euchromatin appears white and heterochromatin appears black on Giemsa staining). They are counted from the centromere out toward the telomeres.
A range of loci is specified in a similar wa
|
https://en.wikipedia.org/wiki/Computer-assisted%20proof
|
A computer-assisted proof is a mathematical proof that has been at least partially generated by computer.
Most computer-aided proofs to date have been implementations of large proofs-by-exhaustion of a mathematical theorem. The idea is to use a computer program to perform lengthy computations, and to provide a proof that the result of these computations implies the given theorem. In 1976, the four color theorem was the first major theorem to be verified using a computer program.
Attempts have also been made in the area of artificial intelligence research to create smaller, explicit, new proofs of mathematical theorems from the bottom up using automated reasoning techniques such as heuristic search. Such automated theorem provers have proved a number of new results and found new proofs for known theorems. Additionally, interactive proof assistants allow mathematicians to develop human-readable proofs which are nonetheless formally verified for correctness. Since these proofs are generally human-surveyable (albeit with difficulty, as with the proof of the Robbins conjecture) they do not share the controversial implications of computer-aided proofs-by-exhaustion.
Methods
One method for using computers in mathematical proofs is by means of so-called validated numerics or rigorous numerics. This means computing numerically yet with mathematical rigour. One uses set-valued arithmetic and in order to ensure that the set-valued output of a numerical program encloses the solution of the original mathematical problem. This is done by controlling, enclosing and propagating round-off and truncation errors using for example interval arithmetic. More precisely, one reduces the computation to a sequence of elementary operations, say . In a computer, the result of each elementary operation is rounded off by the computer precision. However, one can construct an interval provided by upper and lower bounds on the result of an elementary operation. Then one proceeds by replacin
|
https://en.wikipedia.org/wiki/Object%20pool%20pattern
|
The object pool pattern is a software creational design pattern that uses a set of initialized objects kept ready to use – a "pool" – rather than allocating and destroying them on demand. A client of the pool will request an object from the pool and perform operations on the returned object. When the client has finished, it returns the object to the pool rather than destroying it; this can be done manually or automatically.
Object pools are primarily used for performance: in some circumstances, object pools significantly improve performance. Object pools complicate object lifetime, as objects obtained from and returned to a pool are not actually created or destroyed at this time, and thus require care in implementation.
Description
When it is necessary to work with numerous objects that are particularly expensive to instantiate and each object is only needed for a short period of time, the performance of an entire application may be adversely affected. An object pool design pattern may be deemed desirable in cases such as these.
The object pool design pattern creates a set of objects that may be reused. When a new object is needed, it is requested from the pool. If a previously prepared object is available, it is returned immediately, avoiding the instantiation cost. If no objects are present in the pool, a new item is created and returned. When the object has been used and is no longer needed, it is returned to the pool, allowing it to be used again in the future without repeating the computationally expensive instantiation process. It is important to note that once an object has been used and returned, existing references will become invalid.
In some object pools the resources are limited, so a maximum number of objects is specified. If this number is reached and a new item is requested, an exception may be thrown, or the thread will be blocked until an object is released back into the pool.
The object pool design pattern is used in several places in the sta
|
https://en.wikipedia.org/wiki/Miredo
|
Miredo is a Teredo tunneling client designed to allow full IPv6 connectivity to computer systems which are on the IPv4-based Internet but which have no direct native connection to an IPv6 network.
Miredo is included in many Linux and BSD distributions and is also available for recent versions of Mac OS X. (Discontinued)
It includes working implementations of:
a Teredo client
a Teredo relay
a Teredo server
Released under the terms of the GNU General Public License, Miredo is free software.
See also
References
External links
Computer network security
Free network-related software
Free software programmed in C
Network protocols
|
https://en.wikipedia.org/wiki/Holomorph%20%28mathematics%29
|
In mathematics, especially in the area of algebra known as group theory, the holomorph of a group is a group that simultaneously contains (copies of) the group and its automorphism group. The holomorph provides interesting examples of groups, and allows one to treat group elements and group automorphisms in a uniform context. In group theory, for a group , the holomorph of denoted can be described as a semidirect product or as a permutation group.
Hol(G) as a semidirect product
If is the automorphism group of then
where the multiplication is given by
[Eq. 1]
Typically, a semidirect product is given in the form where and are groups and is a homomorphism and where the multiplication of elements in the semidirect product is given as
which is well defined, since and therefore .
For the holomorph, and is the identity map, as such we suppress writing explicitly in the multiplication given in [Eq. 1] above.
For example,
the cyclic group of order 3
where
with the multiplication given by:
where the exponents of are taken mod 3 and those of mod 2.
Observe, for example
and this group is not abelian, as , so that is a non-abelian group of order 6, which, by basic group theory, must be isomorphic to the symmetric group .
Hol(G) as a permutation group
A group G acts naturally on itself by left and right multiplication, each giving rise to a homomorphism from G into the symmetric group on the underlying set of G. One homomorphism is defined as λ: G → Sym(G), (h) = g·h. That is, g is mapped to the permutation obtained by left-multiplying each element of G by g. Similarly, a second homomorphism ρ: G → Sym(G) is defined by (h) = h·g−1, where the inverse ensures that (k) = ((k)). These homomorphisms are called the left and right regular representations of G. Each homomorphism is injective, a fact referred to as Cayley's theorem.
For example, if G = C3 = {1, x, x2 } is a cyclic group of order three, then
(1) = x·1 = x,
(x) = x·x = x2, and
(x2)
|
https://en.wikipedia.org/wiki/Automatic%20vectorization
|
Automatic vectorization, in parallel computing, is a special case of automatic parallelization, where a computer program is converted from a scalar implementation, which processes a single pair of operands at a time, to a vector implementation, which processes one operation on multiple pairs of operands at once. For example, modern conventional computers, including specialized supercomputers, typically have vector operations that simultaneously perform operations such as the following four additions (via SIMD or SPMD hardware):
However, in most programming languages one typically writes loops that sequentially perform additions of many numbers. Here is an example of such a loop, written in C:
for (i = 0; i < n; i++)
c[i] = a[i] + b[i];
A vectorizing compiler transforms such loops into sequences of vector operations. These vector operations perform additions on blocks of elements from the arrays a, b and c. Automatic vectorization is a major research topic in computer science.
Background
Early computers usually had one logic unit, which executed one instruction on one pair of operands at a time. Computer languages and programs therefore were designed to execute in sequence. Modern computers, though, can do many things at once. So, many optimizing compilers perform automatic vectorization, where parts of sequential programs are transformed into parallel operations.
Loop vectorization transforms procedural loops by assigning a processing unit to each pair of operands. Programs spend most of their time within such loops. Therefore, vectorization can significantly accelerate them, especially over large data sets. Loop vectorization is implemented in Intel's MMX, SSE, and AVX, in Power ISA's AltiVec, and in ARM's NEON, SVE and SVE2 instruction sets.
Many constraints prevent or hinder vectorization. Sometimes vectorization can slow down execution, for example because of pipeline synchronization or data-movement timing. Loop dependence analysis identifies loops tha
|
https://en.wikipedia.org/wiki/Washdown
|
Washdown (also wash down) is the process of cleaning or washing a surface for appearance, sanitation, or removal of contamination. It may involve pressure washing. Sometimes wash down involves rinsing with fresh water; other times it involves use of detergents and other chemicals.
Food processing and packaging machinery
Regulations for processing sensitive products such as food and pharmaceuticals require periodic thorough washing and sanitizing. Some equipment can be moved to a central washing facility. Other machinery must be cleaned in place using portable specialized washing equipment. High-pressure cleaning is used with water and cleaning chemicals.
A washdown is usually a manual operation and is designed to kill bacteria and other microorganisms. Automatic cleaning of industrial equipment is often carried out by clean-in-place (CIP) and/or steam-in-place (SIP) operations. CIP (CIP) systems often make use of programmable logic controllers and SCADA software.
Decks and driveways
Washdown is the process of using a stream of water to clean a flat or nearly flat outdoor surface. Typically the area cleaned is a large expanse of concrete or asphalt. The area is cleaned of dirt and debris with the force and dissolving power of stream of water projected from a hose. Generally, one person holds and aims the hose, though if the hose is longer than 300 feet then another person may be required to help move the hose itself. Water is typically squirted from the hose at a pressure of 300 psi. The hose itself can vary in length from 75 to 425 feet. Typically the hose when used by a single person is 300 feet long. The hose itself carries water from a water main which attaches to the hose through what is called a “stinger“. The stinger screws into the water main pipe and is held there.
Also, the stinger as it is pushed down into the water supply pipe opens a seal which releases the water into the hose. At the other end of the hose a nozzle regulates the flow of water
|
https://en.wikipedia.org/wiki/Stroke%20ratio
|
In a reciprocating piston engine, the stroke ratio, defined by either bore/stroke ratio or stroke/bore ratio, is a term to describe the ratio between cylinder bore diameter and piston stroke length. This can be used for either an internal combustion engine, where the fuel is burned within the cylinders of the engine, or external combustion engine, such as a steam engine, where the combustion of the fuel takes place outside the working cylinders of the engine.
A fairly comprehensive yet understandable study of stroke/bore effects was published in Horseless Age, 1916.
Conventions
In a piston engine, there are two different ways of describing the stroke ratio of its cylinders, namely: bore/stroke ratio, and stroke/bore ratio.
Bore/stroke ratio
Bore/stroke is the more commonly used term, with usage in North America, Europe, United Kingdom, Asia, and Australia.
The diameter of the cylinder bore is divided by the length of the piston stroke to give the ratio.
Square, oversquare and undersquare engines
The following terms describe the naming conventions for the configurations of the various bore/stroke ratio:
Square engine
A square engine has equal bore and stroke dimensions, giving a bore/stroke value of exactly 1:1.
Square engine examples
1953 – Ferrari 250 Europa had Lampredi V12 with bore and stroke.
1967 – FIAT 125, 124Sport engine 125A000-90 hp, 125B000-100 hp, 125BC000-110 hp, 1608 ccm, DOHC, bore and stroke.
1970 – Ford 400 had a bore and stroke.
1973 – Kawasaki Z1 and KZ(Z)900 had a bore and stroke.
1973 – British Leyland's Australian division created a 4.4-litre version of the Rover V8 engine, with bore and stroke both measuring 88.9 mm. This engine was exclusively used in the Leyland P76.
1982 - Honda Nighthawk 250 and Honda CMX250C Rebel have a bore and stroke, making it a square engine.
1983 – Mazda FE 2.0L inline four-cylinder engine with a perfectly squared bore and stroke. This engine also features the ideal 1.75:1 rod/stroke ratio.
1
|
https://en.wikipedia.org/wiki/Xenon%20%28video%20game%29
|
Xenon is a 1988 vertical scrolling shooter video game, the first developed by The Bitmap Brothers, and published by Melbourne House which was then owned by Mastertronic. It was featured as a play-by-phone game on the Saturday-morning kids' show Get Fresh.
Xenon was followed in 1989 by Xenon 2: Megablast.
Description
According to the game's instruction manual, the player assumes the role of Darrian, a future space pilot in the Federation, currently at war with a mysterious and violent alien species called the Xenites that has lasted a decade. In response to a mayday transmission from Captain Xod following an attack on his trading fleet, Darrian is forced to travel through Xenite-occupied territory in order to support.
Unlike most vertically scrolling shooters, the player craft has two modes, a flying plane and a ground tank. The transition between crafts can be initiated at almost any time during play (except during the mid- and end-of-level boss sections, as well as certain levels where a certain mode is forced), and the mode chosen depends on the nature of the threat the player faces. Destroying some enemies released power-ups the player could catch to enhance their ship.
Ports
Originally released for the Atari ST, Xenon was quickly ported to other platforms: the Amiga, Amstrad CPC, Commodore 64, DOS, MSX and ZX Spectrum.
An arcade machine version of the game was also released through Mastertronic's Arcadia division which ran on Commodore Amiga hardware.
Reception
Xenon was almost universally well-received on launch, with reviewers from magazines covering a range of platforms all scoring the game very highly. Only German magazine Power Play bucked the trend, awarding it a score of 4.5 out of 10.
Writing in New Computer Express about the 1991 budget re-release, Stuart Campbell stated that although the graphics were "gorgeous" and had "never really been seen before", the gameplay was "simply tedious" and the game was the first to "turn 'style-over-content' int
|
https://en.wikipedia.org/wiki/Tape%20dispenser
|
A tape dispenser is an object that holds a roll of tape and has a mechanism at one end to shear the tape. Dispensers vary widely based on the tape they dispense. Abundant and most common, clear tape dispensers (like those used in an office or at home) are commonly made of plastic, and may be disposable. Other dispensers are stationary and may have sophisticated features to control tape usage and improve ergonomics.
History
Prior to the development of the tape dispenser, 3M's standard clear scotch tape was sold as a roll, and had to be carefully peeled from the end and cut with scissors. To make the product more useful, the scotch tape sales manager at 3M, John Borden, designed the first tape dispenser in 1932, which had a built-in cutting mechanism and would hold the cut end of the tape until its next use.
Handheld dispenser
A handheld dispenser is a variation of handheld tape dispenser used to apply tape to close boxes, etc. Some refer to it as a "tape gun".
Some dispensers are small enough so that the dispenser, with the tape in it, can be taken to the point of application for operator ease. The dispenser allows for a convenient cut-off and helps the operator apply (and sometimes helps rub down) the tape.
Tabletop dispensers
Pull-and-tear
Tabletop or desk dispensers are frequently used to hold the tape and allow the operator to pull off the desired amount, tear the tape off, and take the tape to the job.
Stationary electronic tape dispenser
Tabletop dispensers are available with electrical assists to dispense and cut pressure-sensitive tape to a predetermined length. They are often used in an industrial setting to increase productivity along manufacturing or assembly lines. They eliminate the need to manually measure and cut each individual piece of tape on high volumes of product or packaging. By automating this process, automatic tape dispensers reduce material waste caused by human error. They also reduce the time needed to cut each piece of tape,
|
https://en.wikipedia.org/wiki/American%20Water%20Works%20Association
|
American Water Works Association (AWWA) is an international non-profit, scientific and educational association founded to improve water quality and supply. Established in 1881, it is a lobbying organization representing
a membership (as of 2012) of around 50,000 members worldwide.
In reviewing the success of the Safe Drinking Water Act after 1974, senior EPA officials cite the vital role that AWWA played as kind of a non‐threatening meeting ground, particularly at the local level.
AWWA members include: water utilities, treatment plant operators and managers, scientists, environmentalists, manufacturers, academics, regulators, and others with an interest in water supply and public health. AWWA works through advocacy, communications, conferences, education and training, science and technology, and local action among 43 AWWA Sections throughout North America.
Publications and conferences
To broaden distribution of information on water and related subjects, AWWA publishes the periodicals Journal AWWA and Opflow. AWWA also publishes a variety of books, training manuals, standards, reports and videos for use by water professionals and others. The Association also hosts an annual conference and exposition for the entire organization each summer in North America. Section conferences are also held in all parts of North America. Specialty conferences are held throughout the year on topics including water quality, distribution systems and utility management. Proceedings of the annual and specialty conferences are published by AWWA.
Water industry resources
Through the Partnership for Safe Water AWWA also works with the United States Environmental Protection Agency and other water organizations to help water providers optimize system performance beyond existing regulatory levels.
AWWA offers opportunities for people to meet, learn, and network at the international, national, and section levels. In addition to publications and conferences for water professionals, AWWA h
|
https://en.wikipedia.org/wiki/Essential%20complexity
|
Essential complexity is a numerical measure defined by Thomas J. McCabe, Sr., in his highly cited, 1976 paper better known for introducing cyclomatic complexity. McCabe defined essential complexity as the cyclomatic complexity of the reduced CFG (control-flow graph) after iteratively replacing (reducing) all structured programming control structures, i.e. those having a single entry point and a single exit point (for example if-then-else and while loops) with placeholder single statements.
McCabe's reduction process is intended to simulate the conceptual replacement of control structures (and actual statements they contain) with subroutine calls, hence the requirement for the control structures to have a single entry and a single exit point. (Nowadays a process like this would fall under the umbrella term of refactoring.) All structured programs evidently have an essential complexity of 1 as defined by McCabe because they can all be iteratively reduced to a single call to a top-level subroutine. As McCabe explains in his paper, his essential complexity metric was designed to provide a measure of how far off this ideal (of being completely structured) a given program was. Thus greater than 1 essential complexity numbers, which can only be obtained for non-structured programs, indicate that they are further away from the structured programming ideal.
To avoid confusion between various notions of reducibility to structured programs, it's important to note that McCabe's paper briefly discusses and then operates in the context of a 1973 paper by S. Rao Kosaraju, which gave a refinement (or alternative view) of the structured program theorem. The seminal 1966 paper of Böhm and Jacopini showed that all programs can be [re]written using only structured programming constructs, (aka the D structures: sequence, if-then-else, and while-loop), however, in transforming a random program into a structured program additional variables may need to be introduced (and used in the tes
|
https://en.wikipedia.org/wiki/Hemolysis%20%28microbiology%29
|
Hemolysis (from Greek αιμόλυση, meaning 'blood breakdown') is the breakdown of red blood cells. The ability of bacterial colonies to induce hemolysis when grown on blood agar is used to classify certain microorganisms. This is particularly useful in classifying streptococcal species. A substance that causes hemolysis is a hemolysin.
Types
Alpha-hemolysis
When alpha-hemolysis (α-hemolysis) is present, the agar under the colony is light and greenish. Streptococcus pneumoniae and a group of oral streptococci (Streptococcus viridans or viridans streptococci) display alpha hemolysis. This is sometimes called green hemolysis because of the color change in the agar. Other synonymous terms are incomplete hemolysis and partial hemolysis. Alpha hemolysis is caused by hydrogen peroxide produced by the bacterium, oxidizing hemoglobin producing the green oxidized derivative methemoglobin.
Beta-hemolysis
Beta-hemolysis (β-hemolysis), sometimes called complete hemolysis, is a complete lysis of red cells in the media around and under the colonies: the area appears lightened (yellow) and transparent. Streptolysin, an exotoxin, is the enzyme produced by the bacteria which causes the complete lysis of red blood cells. There are two types of streptolysin: Streptolysin O (SLO) and streptolysin S (SLS). Streptolysin O is an oxygen-sensitive cytotoxin, secreted by most Group A streptococcus (GAS) and Streptococcus dysgalactiae, and interacts with cholesterol in the membrane of eukaryotic cells (mainly red and white blood cells, macrophages, and platelets), and usually results in β-hemolysis under the surface of blood agar. Streptolysin S is an oxygen-stable cytotoxin also produced by most GAS strains which results in clearing on the surface of blood agar. SLS affects immune cells, including polymorphonuclear leukocytes and lymphocytes, and is thought to prevent the host immune system from clearing infection. Streptococcus pyogenes, or Group A beta-hemolytic Strep (GAS), displa
|
https://en.wikipedia.org/wiki/Timeline%20of%20cryptography
|
Below is a timeline of notable events related to cryptography.
B.C.
36th century The Sumerians develop cuneiform writing and the Egyptians develop hieroglyphic writing.
16th century The Phoenicians develop an alphabet
600-500 Hebrew scholars make use of simple monoalphabetic substitution ciphers (such as the Atbash cipher)
c. 400 Spartan use of scytale (alleged)
c. 400 Herodotus reports use of steganography in reports to Greece from Persia (tattoo on shaved head)
100-1 A.D.- Notable Roman ciphers such as the Caesar cipher.
1–1799 A.D.
801–873 A.D. Cryptanalysis and frequency analysis leading to techniques for breaking monoalphabetic substitution ciphers are developed in A Manuscript on Deciphering Cryptographic Messages by the Muslim mathematician, Al-Kindi (Alkindus), who may have been inspired by textual analysis of the Qur'an. He also covers methods of encipherments, cryptanalysis of certain encipherments, and statistical analysis of letters and letter combinations in Arabic.
1355-1418 Ahmad al-Qalqashandi writes Subh al-a 'sha, a 14-volume encyclopedia including a section on cryptology, attributed to Ibn al-Durayhim (1312–1361). The list of ciphers in this work include both substitution and transposition, and for the first time, a cipher with multiple substitutions for each plaintext letter. It also included an exposition on and worked example of cryptanalysis, including the use of tables of letter frequencies and sets of letters which cannot occur together in one word.
1450 The Chinese develop wooden block movable type printing.
1450–1520 The Voynich manuscript, an example of a possibly encoded illustrated book, is written.
1466 Leon Battista Alberti invents polyalphabetic cipher, also first known mechanical cipher machine
1518 Johannes Trithemius' book on cryptology
1553 Bellaso invents Vigenère cipher
1585 Vigenère's book on ciphers
1586 Cryptanalysis used by spymaster Sir Francis Walsingham to implicate Mary, Queen of Scots, in the Babingto
|
https://en.wikipedia.org/wiki/Harlan%20Mills
|
Harlan D. Mills (May 14, 1919 – January 8, 1996) was Professor of Computer Science at the Florida Institute of Technology and founder of Software Engineering Technology, Inc. of Vero Beach, Florida (since acquired by Q-Labs). Mills' contributions to software engineering have had a profound and enduring effect on education and industrial practice. Since earning his Ph.D. in Mathematics at Iowa State University in 1952, Mills led a distinguished career.
As an IBM research fellow, Mills adapted existing ideas from engineering and computer science to software development. These included automata theory, the structured programming theory of Edsger Dijkstra, Robert W. Floyd, and others, and Markov chain-driven software testing. His Cleanroom software development process emphasized top-down design and formal specification. Mills contributed his ideas to the profession in six books and over fifty refereed articles in technical journals.
Mills was termed a "super-programmer", a term which would evolve to the concept in IBM of a "Chief Programmer."
Achievements
Ph.D.: Iowa State University, 1952
Visiting Professor (Part Time) 1975-1987
Adjunct Professor, 1987-1995
Chairman, NSF Computer Science Research Panel on Software Methodology, 1974–77
the Chairman of the First National Conference on Software Engineering, 1975
Editor for IEEE Transactions on Software Engineering, 1975–81
U.S. Representative for Software at the IFIP Congress, 1977
Governor of the IEEE Computer Society, 1980–83
Chairman for IEEE Fall CompCon, 1981
Chairman, Computer Science Panel, U.S. Air Force Scientific Advisory Board, 1986
Awardee, Distinguished Information Sciences Award, DPMA 1985
Designer of initial NFL scheduling algorithm (http://trace.tennessee.edu/utk_harlan/407/)
The ICSE-affiliated colloquium "Science and Engineering for Software Development" is being organized in honor of Harlan D. Mills, and as a recognition of his enduring legacy to the theory and practice of software engi
|
https://en.wikipedia.org/wiki/Spin%20structure
|
In differential geometry, a spin structure on an orientable Riemannian manifold allows one to define associated spinor bundles, giving rise to the notion of a spinor in differential geometry.
Spin structures have wide applications to mathematical physics, in particular to quantum field theory where they are an essential ingredient in the definition of any theory with uncharged fermions. They are also of purely mathematical interest in differential geometry, algebraic topology, and K theory. They form the foundation for spin geometry.
Overview
In geometry and in field theory, mathematicians ask whether or not a given oriented Riemannian manifold (M,g) admits spinors. One method for dealing with this problem is to require that M has a spin structure. This is not always possible since there is potentially a topological obstruction to the existence of spin structures. Spin structures will exist if and only if the second Stiefel–Whitney class w2(M) ∈ H2(M, Z2) of M vanishes. Furthermore, if w2(M) = 0, then the set of the isomorphism classes of spin structures on M is acted upon freely and transitively by H1(M, Z2) . As the manifold M is assumed to be oriented, the first Stiefel–Whitney class w1(M) ∈ H1(M, Z2) of M vanishes too. (The Stiefel–Whitney classes wi(M) ∈ Hi(M, Z2) of a manifold M are defined to be the Stiefel–Whitney classes of its tangent bundle TM.)
The bundle of spinors πS: S → M over M is then the complex vector bundle associated with the corresponding principal bundle πP: P → M of spin frames over M and the spin representation of its structure group Spin(n) on the space of spinors Δn. The bundle S is called the spinor bundle for a given spin structure on M.
A precise definition of spin structure on manifold was possible only after the notion of fiber bundle had been introduced; André Haefliger (1956) found the topological obstruction to the existence of a spin structure on an orientable Riemannian manifold and Max Karoubi (1968) extended this result
|
https://en.wikipedia.org/wiki/Stadiametric%20rangefinding
|
Stadiametric rangefinding, or the stadia method, is a technique of measuring distances with a telescopic instrument. The term stadia comes from a Greek unit of length Stadion (equal to 600 Greek feet, pous) which was the typical length of a sports stadium of the time. Stadiametric rangefinding is used for surveying and in the telescopic sights of firearms, artillery pieces, or tank guns, as well as some binoculars and other optics. It is still widely used in long-range military sniping, but in many professional applications it is being replaced with microwave, infrared, or laser rangefinding methods. Although much easier to use, electronic rangefinders can give away the shooter's position to a well-equipped adversary, and the need for accurate range estimation has existed for much longer than electronic rangefinders small and rugged enough to be suitable for military use.
Principle
The stadia method is based upon the principle of similar triangles. This means that, for a triangle with a given angle, the ratio of opposite side length to adjacent side length (tangent) is constant. By using a reticle with marks of a known angular spacing, the principle of similar triangles can be used to find either the distance to objects of known size or the size of objects at a known distance. In either case, the known parameter is used, in conjunction with the angular measurement, to derive the length of the other side.
Stadiametric rangefinding often uses the milliradian ("mil" or "mrad") as the unit of angular measurement. Since a radian is defined as the angle formed when the length of a circular arc equals the radius of the circle, a milliradian is the angle formed when the length of a circular arc equals 1/1000 of the radius of the circle. For telescopic angles, the approximations of greatly simplify the trigonometry, enabling one to scale objects measured in milliradians through a telescope by a factor of 1000 for distance or height. An object 5 meters high, for exa
|
https://en.wikipedia.org/wiki/Financial%20modeling
|
Financial modeling is the task of building an abstract representation (a model) of a real world financial situation. This is a mathematical model designed to represent (a simplified version of) the performance of a financial asset or portfolio of a business, project, or any other investment.
Typically, then, financial modeling is understood to mean an exercise in either asset pricing or corporate finance, of a quantitative nature. It is about translating a set of hypotheses about the behavior of markets or agents into numerical predictions. At the same time, "financial modeling" is a general term that means different things to different users; the reference usually relates either to accounting and corporate finance applications or to quantitative finance applications.
Accounting
In corporate finance and the accounting profession, financial modeling typically entails financial statement forecasting; usually the preparation of detailed company-specific models used for decision making purposes and financial analysis.
Applications include:
Business valuation and stock valuation - especially via discounted cash flow, but including other valuation approaches
Scenario planning and management decision making ("what is"; "what if"; "what has to be done")
Budgeting: revenue forecasting and analytics; production budgeting; operations budgeting
Capital budgeting, including cost of capital (i.e. WACC) calculations
Cash flow forecasting; working capital- and treasury management; asset and liability management
Financial statement analysis / ratio analysis (including of operating- and finance leases, and R&D)
Transaction analytics: M&A, PE, VC, LBO, IPO, Project finance, P3
Credit decisioning: Credit analysis, Consumer credit risk; impairment- and provision-modeling
Management accounting: Activity-based costing, Profitability analysis, Cost analysis, Whole-life cost, Managerial risk accounting
To generalize as to the nature of these models:
firstly, as they are built a
|
https://en.wikipedia.org/wiki/VAXELN
|
VAXELN (typically pronounced "VAX-elan") is a discontinued real-time operating system for the VAX family of computers produced by the Digital Equipment Corporation (DEC) of Maynard, Massachusetts.
As with RSX-11 and VMS, Dave Cutler was the principal force behind the development of this operating system. Cutler's team developed the product after moving to the Seattle, Washington area to form the DECwest Engineering Group; DEC's first engineering group outside New England. Initial target platforms for VAXELN were the backplane interconnect computers such as the V-11 family. When VAXELN was well under way, Cutler spearheaded the next project, the MicroVAX I, the first VAX microcomputer. Although it was a low-volume product compared with the New England-developed MicroVAX II, the MicroVAX I demonstrated the set of architectural decisions needed to support a single-board implementation of the VAX computer family, and it also provided a platform for embedded system applications written for VAXELN.
The VAXELN team made the decision, for the first release, to use the programming language Pascal as its system programming language. The development team built the first product in approximately 18 months. Other languages, including C, Ada, and Fortran were supported in later releases of the system as optional extras. A relational database, named VAX Rdb/ELN was another optional component of the system. Later versions of VAXELN supported an X11 server named EWS (VAXELN Window Server). VAXELN with EWS was used as the operating system for the VT1300 X terminal, and was sometimes used to convert old VAXstation hardware into X terminals. Beginning with version 4.3, VAXELN gained support for TCP/IP networking and a subset of POSIX APIs.
VAXELN allowed the creation of a self-contained embedded system application that would run on VAX (and later MicroVAX) hardware with no other operating system present. The system was debuted in Las Vegas in the early 1980s, with a variety of amusi
|
https://en.wikipedia.org/wiki/QLogic
|
QLogic Corporation was an American manufacturer of networking server and storage networking connectivity and application acceleration products, based in Aliso Viejo, California through 2016.
QLogic's products include Fibre Channel adapters, converged network adapters for Fibre Channel over Ethernet (FCoE), Ethernet network interface controllers, iSCSI adapters, and application-specific integrated circuits (ASICs).
It was a public company from 1992 to 2016.
History
QLogic was created in 1992 after being spun off by Emulex. QLogic's original business was disk controllers. QLogic had its initial public offering in 1994 and was traded on NASDAQ under the symbol QLGC.
Originally located in a Costa Mesa, California building adjacent to Emulex, it competed against its parent company in the market for Fibre Channel controllers for storage area networks.
QLogic acquired companies including NetXen.
Integrated circuit designer Silicon Design Resources Inc. based in Austin, Texas, was acquired for about $2 million in 1998.
In May 2000, QLogic acquired Fibre Channel switch maker Ancor Communications for about $1.7 billion in stock.
Little Mountain Group, founded in 1999 and developer of iSCSI technology, was acquired in January 2001 for about $30 million.
The compiler company PathScale was acquired for about $109 million in February 2006.
Silverstorm Technologies, which designed InfiniBand products, was acquired in October 2006 for about $60 million.
After attempting to use PathScale for cluster computing over InfiniBand, the compiler business was sold to SiCortex in August 2006.
QLogic was led by chairman H.K. Desai from 1996, who became executive chairman in 2010 until his death in June 2014.
In 2012, the InfiniBand products were sold to Intel for $125 million.
Simon Biddiscombe became chief executive in November 2010, until resigning in May 2013 after two years of falling revenue.
Prasad Rampalli became chief executive a few months later, until August 2015.
Jean Hu becam
|
https://en.wikipedia.org/wiki/FC-HBA%20API
|
In computing, the FC-HBA API (also called the SNIA Common HBA API) is an Application Programming Interface for Host Bus Adapters connecting computers to hard disks via a Fibre Channel network. It was developed by the Storage Networking Industry Association
and published by the T11.5 committee of INCITS
An "early implementers version" was published in 2000, and the current version was completed in 2002.
According to the FAQ,
"the HBA API has been overwhelmingly adopted by Storage Area Network vendors to help manage, monitor, and deploy storage area networks in an interoperable way." Vendors supply their own library (written in C) as plugins for a common HBA library.
Operating system support
Windows Server 2003, AIX 5,HPUX and Solaris include support for FC-HBA API and it is being added to Linux.
See also
SM HBA
References
External links
The Common HBA API specification Version 2.18
The Fibre Channel HBA API Project at SourceForge
AIX 5L Differences Guide (see section 4.10)
MacOS programming tools
Programming tools for Windows
Linux programming tools
Fibre Channel
Storage software
|
https://en.wikipedia.org/wiki/10%2C000%2C000
|
10,000,000 (ten million) is the natural number following 9,999,999 and preceding 10,000,001.
In scientific notation, it is written as 107.
In South Asia except for Sri Lanka, it is known as the crore.
In Cyrillic numerals, it is known as the vran (вран — raven).
Selected 8-digit numbers (10,000,001–99,999,999)
10,000,001 to 19,999,999
10,000,019 = smallest 8-digit prime number
10,001,628 = smallest triangular number with 8 digits and the 4,472nd triangular number
10,004,569 = 31632, the smallest 8-digit square
10,077,696 = 2163 = 69, the smallest 8-digit cube
10,172,638 = number of reduced trees with 32 nodes
10,556,001 = 32492 = 574
10,609,137 = Leyland number
10,976,184 = logarithmic number
11,111,111 = repunit
11,316,496 = 33642 = 584
11,390,625 = 33752 = 2253 = 156
11,405,773 = Leonardo prime
11,436,171 = Keith number
11,485,154 = Markov number
11,881,376 = 265
11,943,936 = 34562
12,117,361 = 34812 = 594
12,252,240 = highly composite number, smallest number divisible by all the numbers 1 through 18
12,648,430 = hexadecimal C0FFEE, resembling the word "coffee"; used as a placeholder in computer programming, see hexspeak.
12,890,625 = 1-automorphic number
12,960,000 = 36002 = 604 = (3·4·5)4, Plato's "nuptial number" (Republic VIII; see regular number)
12,988,816 = number of different ways of covering an 8-by-8 square with 32 1-by-2 dominoes
13,079,255 = number of free 16-ominoes
13,782,649 = Markov number
13,845,841 = 37212 = 614
14,348,907 = 2433 = 275 = 315
14,352,282 = Leyland number
14,776,336 = 38442 = 624
14,930,352 = Fibonacci number
15,485,863 = 1,000,000th prime number
15,548,694 = Fine number
15,752,961 = 39692 = 634
15,994,428 = Pell number
16,003,008 = 2523
16,609,837 = Markov number
16,733,779 = number of ways to partition {1,2,...,10} and then partition each cell (block) into subcells.
16,777,216 = 40962 = 2563 = 644 = 166 = 88 = 412 = 224 — hexadecimal "million" (0x1000000), number of possible colors in 24/3
|
https://en.wikipedia.org/wiki/100%2C000%2C000
|
100,000,000 (one hundred million) is the natural number following 99,999,999 and preceding 100,000,001.
In scientific notation, it is written as 108.
East Asian languages treat 100,000,000 as a counting unit, significant as the square of a myriad, also a counting unit. In Chinese, Korean, and Japanese respectively it is yi () (or in ancient texts), eok () and oku (). These languages do not have single words for a thousand to the second, third, fifth powers, etc.
100,000,000 is also the fourth power of 100 and also the square of 10000.
Selected 9-digit numbers (100,000,001–999,999,999)
100,000,001 to 199,999,999
100,000,007 = smallest nine digit prime
100,005,153 = smallest triangular number with 9 digits and the 14,142nd triangular number
100,020,001 = 100012, palindromic square
100,544,625 = 4653, the smallest 9-digit cube
102,030,201 = 101012, palindromic square
102,334,155 = Fibonacci number
102,400,000 = 405
104,060,401 = 102012 = 1014, palindromic square
105,413,504 = 147
107,890,609 = Wedderburn-Etherington number
111,111,111 = repunit, square root of 12345678987654321
111,111,113 = Chen prime, Sophie Germain prime, cousin prime.
113,379,904 = 106482 = 4843 = 226
115,856,201 = 415
119,481,296 = logarithmic number
120,528,657 = number of centered hydrocarbons with 27 carbon atoms
121,242,121 = 110112, palindromic square
123,454,321 = 111112, palindromic square
123,456,789 = smallest zeroless base 10 pandigital number
125,686,521 = 112112, palindromic square
126,390,032 = number of 34-bead necklaces (turning over is allowed) where complements are equivalent
126,491,971 = Leonardo prime
129,140,163 = 317
129,145,076 = Leyland number
129,644,790 = Catalan number
130,150,588 = number of 33-bead binary necklaces with beads of 2 colors where the colors may be swapped but turning over is not allowed
130,691,232 = 425
134,217,728 = 5123 = 89 = 227
134,218,457 = Leyland number
136,048,896 = 116642 = 1084
139,854,276 = 118262, the sma
|
https://en.wikipedia.org/wiki/Oxidase%20test
|
The oxidase test is used to determine whether an organism possesses the cytochrome c oxidase enzyme. The test is used as an aid for the differentiation of Neisseria, Moraxella, Campylobacter and Pasteurella species (oxidase positive). It is also used to differentiate pseudomonads from related species.
Classification
Strains may be either oxidase-positive (OX+) or oxidase-negative (OX-).
OX+
OX+ normally means the bacterium contains cytochrome c oxidase (also known as Complex IV) and can therefore use oxygen for energy production by converting O2 to H2O2 or H2O with an electron transfer chain.
The Pseudomonadaceae are typically OX+.
The Gram-negative diplococci Neisseria and Moraxella are oxidase-positive.
Many Gram-negative, spiral curved rods are also oxidase-positive, which includes Helicobacter pylori, Vibrio cholerae, and Campylobacter jejuni.
Oxidase variable
Legionella pneumophila may be oxidase-positive.
OX−
OX− normally means the bacterium does not contain cytochrome c oxidase and, therefore, either cannot use oxygen for energy production with an electron transfer chain or employs a different cytochrome for transferring electrons to oxygen.
Enterobacteriaceae are typically OX−.
Mechanism
The test uses disks impregnated with a reagent such as N,N,N′,N′-tetramethyl-p-phenylenediamine, TMPD (or N,N-dimethyl-p-phenylenediamine, DMPD, which is also a redox indicator). The reagent is a dark-blue to maroon color when oxidized, and colorless when reduced. Oxidase-positive bacteria possess cytochrome oxidase or indophenol oxidase (an iron-containing hemoprotein). These both catalyze the transport of electrons from donor compounds (NADH) to electron acceptors (usually oxygen). The test reagent TMPD acts as an artificial electron donor for the enzyme oxidase. The oxidized reagent forms the colored compound indophenol blue. The cytochrome system is usually only present in aerobic organisms that are capable of using oxygen as the terminal electron acceptor. Th
|
https://en.wikipedia.org/wiki/Circuit%20design
|
The process of circuit design can cover systems ranging from complex electronic systems down to the individual transistors within an integrated circuit. One person can often do the design process without needing a planned or structured design process for simple circuits. Still, teams of designers following a systematic approach with intelligently guided computer simulation are becoming increasingly common for more complex designs. In integrated circuit design automation, the term "circuit design" often refers to the step of the design cycle which outputs the schematics of the integrated circuit. Typically this is the step between logic design and physical design.
Process
Traditional circuit design usually involves several stages. Sometimes, a design specification is written after liaising with the customer. A technical proposal may be written to meet the requirements of the customer specification. The next stage involves synthesising on paper a schematic circuit diagram, an abstract electrical or electronic circuit that will meet the specifications. A calculation of the component values to meet the operating specifications under specified conditions should be made. Simulations may be performed to verify the correctness of the design.
A breadboard or other prototype version of the design for testing against specification may be built. It may involve making any alterations to the circuit to achieve compliance. A choice as to a method of construction and all the parts and materials to be used must be made. There is a presentation of component and layout information to draughtspersons and layout and mechanical engineers for prototype production. This is followed by the testing or type-testing several prototypes to ensure compliance with customer requirements. Usually, there is a signing and approval of the final manufacturing drawings, and there may be post-design services (obsolescence of components, etc.).
Specification
The process of circuit design begins
|
https://en.wikipedia.org/wiki/Evernote
|
Evernote is a note-taking and task-management application developed by the Evernote Corporation. It is intended for archiving and creating notes with embedded photos, audio, and saved web content. Notes are stored in virtual "notebooks" and can be tagged, annotated, edited, searched, and exported.
Evernote is available on Android, iOS, macOS, Chrome OS (via Web), Microsoft Windows, as well as a web client. It offers free and paid plans for use.
Architecture
Coding and versions
In 2010, the programming language used to write Evernote's software was changed from C# for version 3.5 to C++ in version 4.0 to improve performance.
Data entry
In addition to keyboard input of typed notes, Evernote also supports image capture from cameras on supported devices and voice note recording. In some situations, text that appears in captured images can be recognized using OCR and annotated. Evernote also supports touch and tablet screens with handwriting recognition. Evernote web-clipping plugins are available for most popular Internet browsers and allow marked sections of webpages to be captured and clipped to Evernote. If no section of a webpage has been highlighted, Evernote can clip the full page. Evernote also supports the ability to e-mail notes to the service, allowing for automated note entry via e-mail rules or filters.
Where suitable hardware is available, Evernote can automatically add geolocation tags to notes.
As of November 2018, Evernote Pro integrates directly with Google Drive, Microsoft Outlook, Microsoft Teams, and Slack, and Evernote Pro adds an integration with Salesforce. All versions of Evernote also support integrations through IFTTT and Zapier. In 2013, Evernote deprecated its direct integration with Twitter in favor of these third-party services.
Data storage and access
On supported operating systems, Evernote allows users to store and edit notes on their local machine, using a SQLite database in Windows.
Users with Internet access and an Evernote
|
https://en.wikipedia.org/wiki/Algebraic%20semantics%20%28mathematical%20logic%29
|
In mathematical logic, algebraic semantics is a formal semantics based on algebras studied as part of algebraic logic. For example, the modal logic S4 is characterized by the class of topological boolean algebras—that is, boolean algebras with an interior operator. Other modal logics are characterized by various other algebras with operators. The class of boolean algebras characterizes classical propositional logic, and the class of Heyting algebras propositional intuitionistic logic. MV-algebras are the algebraic semantics of Łukasiewicz logic.
See also
Algebraic semantics (computer science)
Lindenbaum–Tarski algebra
Further reading
(2nd published by ASL in 2009) open access at Project Euclid
Good introduction for readers with prior exposure to non-classical logics but without much background in order theory and/or universal algebra; the book covers these prerequisites at length. The book, however, has been criticized for poor and sometimes incorrect presentation of abstract algebraic logic results.
Mathematical logic
|
https://en.wikipedia.org/wiki/ZetaGrid
|
ZetaGrid was at one time the largest distributed computing project, designed to explore the non-trivial roots of the Riemann zeta function, checking over one billion roots a day.
Roots of the zeta function are of particular interest in mathematics; a single root out of alignment would disprove the Riemann hypothesis, with far-reaching consequences for all of mathematics. , no counterexample to the Riemann hypothesis has been found.
The project ended in November 2005 due to instability of the hosting provider. The first more than 1013 zeroes were checked. The project administrator stated that after the results were analyzed, they would be posted on the American Mathematical Society website. The official status remains unclear, however, as it was never published nor independently verified. This is likely because there was no evidence that each zero was actually computed, as there was no process implemented to check each one as it was calculated.
References
External links
Home page (Web archive)
Grid computing
Zeta and L-functions
Hilbert's problems
Experimental mathematics
|
https://en.wikipedia.org/wiki/Intertrust%20Technologies%20Corporation
|
Intertrust Technologies Corporation is a software technology company specializing in trusted distributed computing. Intertrust’s product lines consist of a DataOps platform, Application protection and Content protection solutions. Much of Intertrust's digital rights management (DRM) business is based on the Marlin DRM technology, which Intertrust founded along with four consumer electronics companies: Sony, Panasonic, Philips, and Samsung.
Intertrust is headquartered in Silicon Valley and has offices in Tokyo, Seoul, London, Paris, Mumbai, Beijing, Tallinn, Riga and Bangalore.
History
Victor H. Shear received a BA in sociology from Brandeis University, served as chief executive of Data Scientific Corporation from 1982 to 1985, and then co-founded Personal Library Software. Around 1985, Shear attempted to obtain one of the first US patents for software. For example, one patent covered metering and protecting data on a compact disc from 1986.
The company began under the name Electronic Publishing Resources in January 1990. David M. Van Wie became involved with Intertrust in early 1991. Intertrust's technology, called digital rights management (DRM), enabled trusted transactions, from healthcare, enterprise computing to entertainment and consumer electronics. In 1995, the company announced its technology would be used by Novell. Former Bell Labs Fellow David P. Maher became chief technology officer in 1999. In 1996, Electronic Publishing Resources was renamed Intertrust Technologies.
At the peak of the Internet bubble in October 1999, despite a lack of any earnings, Intertrust had its initial public offering. It was listed on the NASDAQ exchange with symbol ITRU. Within six months, the share price rose from $9 to $35, and a secondary offering on April 12, 2000 raised another $92 million.
In 2001, two companies were acquired: PublishOne, Inc., and ZeroGravity Technologies, and Nokia invested $20 million. However, by the end of 2001 losses had climbed to over $115
|
https://en.wikipedia.org/wiki/Micrococcal%20nuclease
|
Micrococcal nuclease (, S7 Nuclease, MNase, spleen endonuclease, thermonuclease, nuclease T, micrococcal endonuclease, nuclease T''', staphylococcal nuclease, spleen phosphodiesterase, Staphylococcus aureus nuclease, Staphylococcus aureus nuclease B, ribonucleate (deoxynucleate) 3'-nucleotidohydrolase) is an endo-exonuclease that preferentially digests single-stranded nucleic acids. The rate of cleavage is 30 times greater at the 5' side of A or T than at G or C and results in the production of mononucleotides and oligonucleotides with terminal 3'-phosphates. The enzyme is also active against double-stranded DNA and RNA and all sequences will be ultimately cleaved.
Characteristics
The enzyme has a molecular weight of 16.9kDa.
The pH optimum is reported as 9.2. The enzyme activity is strictly dependent on Ca2+ and the pH optimum varies according to Ca2+ concentration. The enzyme is therefore easily inactivated by EGTA.
Sources
This enzyme is the extracellular nuclease of Staphylococcus aureus. Two strains, V8 and Foggi, yield almost identical enzymes. A common source is E.coli'' cells carrying a cloned nuc gene encoding Staphylococcus aureus extracellular nuclease (micrococcal nuclease).
Structure
The 3-dimensional structure of micrococcal nuclease (then called Staphyloccal nuclease) was solved very early in the history of protein crystallography, in 1969, deposited as now-obsolete Protein Data Bank file 1SNS. Higher-resolution, more recent crystal structures are available for the apo form as Protein Data Bank file 1SNO: and for the thymidine-diphosphate-inhibited form as Protein Data Bank file 3H6M: or 1SNC: . As seen in the ribbon diagram above, the nuclease molecule has 3 long alpha helices and a 5-stranded, barrel-shaped beta sheet, in an arrangement known as the OB-fold (for oligonucleotide-binding fold) as classified in the SCOP database.
Applications
CUT&RUN sequencing, antibody-targeted controlled cleavage by micrococcal nuclease for transcriptomic p
|
https://en.wikipedia.org/wiki/Unifying%20Theories%20of%20Programming
|
Unifying Theories of Programming (UTP) in computer science deals with program semantics. It shows how denotational semantics, operational semantics and algebraic semantics can be combined in a unified framework for the formal specification, design and implementation of programs and computer systems.
The book of this title by C.A.R. Hoare and He Jifeng was published in the Prentice Hall International Series in Computer Science in 1998 and is now freely available on the web.
Theories
The semantic foundation of the UTP is the first-order predicate calculus, augmented with fixed point constructs from second-order logic. Following the tradition of Eric Hehner, programs are predicates in the UTP, and there is no distinction between programs and specifications at the semantic level. In the words of Hoare:
A computer program is identified with the strongest predicate describing every relevant observation that can be made of the behaviour of a computer executing that program.
In UTP parlance, a theory is a model of a particular programming paradigm. A UTP theory is composed of three ingredients:
an alphabet, which is a set of variable names denoting the attributes of the paradigm that can be observed by an external entity;
a signature, which is the set of programming language constructs intrinsic to the paradigm; and
a collection of healthiness conditions, which define the space of programs that fit within the paradigm. These healthiness conditions are typically expressed as monotonic idempotent predicate transformers.
Program refinement is an important concept in the UTP. A program is refined by if and only if every observation that can be made of is also an observation of .
The definition of refinement is common across UTP theories:
where denotes the universal closure of all variables in the alphabet.
Relations
The most basic UTP theory is the alphabetised predicate calculus, which has no alphabet restrictions or healthiness conditions. The theory of relatio
|
https://en.wikipedia.org/wiki/He%20Jifeng
|
He Jifeng (, born August 1943) is a Chinese computer scientist.
He Jifeng graduated from the mathematics department of Fudan University in 1965. From 1965 to 1985, he was an instructor at East China Normal University. During 1980–81, he was a visiting scholar at Stanford University and the University of San Francisco in California, United States.
From 1984 to 1998, He Jifeng was a senior research fellow at the Programming Research Group in the Oxford University Computing Laboratory (now the Oxford University Department of Computer Science). He worked extensively on formal aspects of computing science. In particular, he worked with Prof. Sir Tony Hoare, latterly on Unifying Theories of Programming, resulting in a book of that name.
Since 1986, He Jifeng has been Professor of Computer Science at East China Normal University in Shanghai. In 1996, he also became Professor of Computer Science at Shanghai Jiao Tong University.
In 1998, he became a senior research fellow at the International Institute for Software Technology (UNU-IIST), United Nations University, based in Macau. He moved back to Shanghai in 2005.
He Jifeng's research interests include sound methods for the specification of computer systems, communications, applications, standards, and techniques for designing and implementing those specifications in software and/or hardware with high reliability.
In 2005, he was elected to the Chinese Academy of Sciences. In 2013, his 70th birthday was celebrated at East China Normal University with an international three-day Festschrift in association with the International Conference on Theoretical Aspects of Computing (ICTAC). Ten years later in 2023, his 80th birthday was celebrated at the Shanghai Science Hall with a hybrid international two-day Festschrift Symposium. Since 2019, he has been a Distinguished Professor at Tongji University in Shanghai.
Books
He Jifeng has written a number of computer science books, including:
He Jifeng, Provably Correct System
|
https://en.wikipedia.org/wiki/Winding%20engine
|
A winding engine is a stationary engine used to control a cable, for example to power a mining hoist at a pit head. Electric hoist controllers have replaced proper winding engines in modern mining, but use electric motors that are also traditionally referred to as winding engines.
Early winding engines were hand, or more usually horse powered.
The first powered winding engines were stationary steam engines. The demand for winding engines was one factor that drove James Watt to develop his rotative beam engine, with its ability continuously to turn a winding drum, rather than the early reciprocating beam engines that were only useful for working pumps.
They differ from most other stationary steam engines in that, like a steam locomotive, they need to be able to stop frequently and also reverse. This requires more complex valve gear and other controls than are needed on engines used in mills or to drive pumps.
External links
Winding Engines
References
Mining equipment
Stationary engines
|
https://en.wikipedia.org/wiki/Facing%20Identification%20Mark
|
The Facing Identification Mark, or FIM, is a bar code designed by the United States Postal Service to assist in the automated processing of mail. The FIM is a set of vertical bars printed on the envelope or postcard near the upper edge, just to the left of the postage area (the area where the postage stamp or its equivalent is placed). The FIM is intended for use primarily on preprinted envelopes and postcards and is applied by the company printing the envelopes or postcards, not by the USPS.
The FIM is a nine-bit code consisting of ones (vertical bars) and zeroes (blank spaces). The following five codes are in use:
FIM A: || | || (110010011)
FIM B: | || || | (101101101)
FIM C: || | | || (110101011)
FIM D: ||| | ||| (111010111)
FIM E: | | | | (101000101)
All defined FIMs start and end with a bar, and are palindromic, reading the same forward and backward. Thus, there are only 16 possible FIMs, 11 if the current limits of at most 3 consecutive bars or spaces are maintained.
The FIM allows the proper facing of mail for cancellation. It also identifies the manner in which postage is paid (e.g., business reply mail or Information Based Indicia (IBI) postage) and whether that business reply mail has a barcode, typically an Intelligent Mail Barcode or the older POSTNET barcode. If the barcode is present, the mail can be sent directly to a sorter.
The five codes have the following uses:
FIM A is used for mail bearing regular postage and an Intelligent Mail Barcode. It is commonly used by preprinted courtesy reply mail and metered reply mail, but may be applied to any mail to speed delivery.
FIM B is used for business reply mail without a preprinted barcode. Because this costs more than barcoded mail, it is rarely used.
FIM C is used for business reply mail with a preprinted Intelligent Mail Barcode.
FIM D is used only with IBI postage.
FIM E is used to mark Share Mail, where the Intelligent Mail Barcode is used as postage.
References
External links
Dom
|
https://en.wikipedia.org/wiki/Quantum%20flux%20parametron
|
A Quantum Flux Parametron (QFP) is a digital logic implementation technology based on superconducting Josephson junctions. QFP's were invented by Eiichi Goto at the University of Tokyo as an improvement over his earlier parametron based digital logic technology, which did not use superconductivity effects or Josephson junctions. The Josephson junctions on QFP integrated circuits to improve speed and energy efficiency enormously over the parametrons.
In some applications, the complexity of the cryogenic cooling system required is negligible compared to the potential speed gains. While his design makes use of quantum principles, it is not a quantum computer technology, gaining speed only through higher clock speeds.
Apart from the speed advantage over traditional CMOS integrated circuit design is that parametrons can be operated with zero energy loss (no local increase in entropy), making reversible computing possible. Low energy use and heat generation is critical in supercomputer design, where thermal load per unit volume has become one of the main limiting factors.
A related technology is the Rapid Single Flux Quantum digital logic.
References
External links
Parametron, The History of Computing project
Parametron, early computers, Information Processing Society of Japan
Digital electronics
Quantum electronics
Superconductivity
|
https://en.wikipedia.org/wiki/List%20of%20uniform%20polyhedra
|
In geometry, a uniform polyhedron is a polyhedron which has regular polygons as faces and is vertex-transitive (transitive on its vertices, isogonal, i.e. there is an isometry mapping any vertex onto any other). It follows that all vertices are congruent, and the polyhedron has a high degree of reflectional and rotational symmetry.
Uniform polyhedra can be divided between convex forms with convex regular polygon faces and star forms. Star forms have either regular star polygon faces or vertex figures or both.
This list includes these:
all 75 nonprismatic uniform polyhedra;
a few representatives of the infinite sets of prisms and antiprisms;
one degenerate polyhedron, Skilling's figure with overlapping edges.
It was proven in that there are only 75 uniform polyhedra other than the infinite families of prisms and antiprisms. John Skilling discovered an overlooked degenerate example, by relaxing the condition that only two faces may meet at an edge. This is a degenerate uniform polyhedron rather than a uniform polyhedron, because some pairs of edges coincide.
Not included are:
The uniform polyhedron compounds.
40 potential uniform polyhedra with degenerate vertex figures which have overlapping edges (not counted by Coxeter);
The uniform tilings (infinite polyhedra)
11 Euclidean convex uniform tilings;
28 Euclidean nonconvex or apeirogonal uniform tilings;
Infinite number of uniform tilings in hyperbolic plane.
Any polygons or 4-polytopes
Indexing
Four numbering schemes for the uniform polyhedra are in common use, distinguished by letters:
[C] Coxeter et al., 1954, showed the convex forms as figures 15 through 32; three prismatic forms, figures 33–35; and the nonconvex forms, figures 36–92.
[W] Wenninger, 1974, has 119 figures: 1–5 for the Platonic solids, 6–18 for the Archimedean solids, 19–66 for stellated forms including the 4 regular nonconvex polyhedra, and ended with 67–119 for the nonconvex uniform polyhedra.
[K] Kaleido, 1993: The 80 figure
|
https://en.wikipedia.org/wiki/Hoist%20controller
|
A hoist controller is the controller for a hoist. The term is used primarily in the context of electrically operated hoists, but it is apparent that the control systems of many 20th century steam hoists also incorporated controllers of significant complexity. Consider the control system of the Quincy Mine No. 2 Hoist. This control system included interlocks to close the throttle valve at the end of trip and to prevent opening the throttle again until the winding engine was reversed. The control system also incorporated a governor to control the speed of the hoist and indicator wheels to show the hoist operator the positions of the skips in the mine shaft.
The hoist controllers for modern electric mining hoists have long included such features as automatic starting of the hoist when the weight of coal or ore in the skip reaches a set point, automatic acceleration of the hoist to full speed and automatic deceleration at the end of travel.
Hoist controllers need both velocity and absolute position references taken, typically taken from the winding drum of the hoist. Modern hoist controllers replace many of the mechanical analog mechanisms of earlier controllers with digital control systems.
See also
Hydraulic hooklift hoist
References
Mining equipment
|
https://en.wikipedia.org/wiki/Busemann%20function
|
In geometric topology, Busemann functions are used to study the large-scale geometry of geodesics in Hadamard spaces and in particular Hadamard manifolds (simply connected complete Riemannian manifolds of nonpositive curvature). They are named after Herbert Busemann, who introduced them; he gave an extensive treatment of the topic in his 1955 book "The geometry of geodesics".
Definition and elementary properties
Let be a metric space. A geodesic ray is a path which minimizes distance everywhere along its length. i.e., for all ,
Equivalently, a ray is an isometry from the "canonical ray" (the set equipped with the Euclidean metric) into the metric space X.
Given a ray γ, the Busemann function is defined by
Thus, when t is very large, the distance is approximately equal to . Given a ray γ, its Busemann function is always well-defined: indeed the right hand side above , tends pointwise to the left hand side on compacta, since is bounded above by and non-increasing since, if ,
It is immediate from the triangle inequality that
so that is uniformly continuous. More specifically, the above estimate above shows that
Busemann functions are Lipschitz functions with constant 1.
By Dini's theorem, the functions tend to uniformly on compact sets as t tends to infinity.
Example: Poincaré disk
Let be the unit disk in the complex plane with the Poincaré metric
Then, for and , the Busemann function is given by
where the term in brackets on the right hand side is the Poisson kernel for the unit disk and corresponds to the radial geodesic from the origin towards ,
. The computation of can be reduced to that of , since the metric is invariant under Möbius transformations in ; the geodesics through have the form where is the 1-parameter subgroup of ,
The formula above also completely determines the Busemann function by Möbius invariance.
Busemann functions on a Hadamard space
In a Hadamard space, where any two points are joined by a unique geodesic
|
https://en.wikipedia.org/wiki/Hadamard%20space
|
In geometry, an Hadamard space, named after Jacques Hadamard, is a non-linear generalization of a Hilbert space. In the literature they are also equivalently defined as complete CAT(0) spaces.
A Hadamard space is defined to be a nonempty complete metric space such that, given any points and there exists a point such that for every point
The point is then the midpoint of and
In a Hilbert space, the above inequality is equality (with ), and in general an Hadamard space is said to be if the above inequality is equality. A flat Hadamard space is isomorphic to a closed convex subset of a Hilbert space. In particular, a normed space is an Hadamard space if and only if it is a Hilbert space.
The geometry of Hadamard spaces resembles that of Hilbert spaces, making it a natural setting for the study of rigidity theorems. In a Hadamard space, any two points can be joined by a unique geodesic between them; in particular, it is contractible. Quite generally, if is a bounded subset of a metric space, then the center of the closed ball of the minimum radius containing it is called the circumcenter of Every bounded subset of a Hadamard space is contained in the smallest closed ball (which is the same as the closure of its convex hull). If is the group of isometries of a Hadamard space leaving invariant then fixes the circumcenter of (Bruhat–Tits fixed point theorem).
The basic result for a non-positively curved manifold is the Cartan–Hadamard theorem. The analog holds for a Hadamard space: a complete, connected metric space which is locally isometric to a Hadamard space has an Hadamard space as its universal cover. Its variant applies for non-positively curved orbifolds. (cf. Lurie.)
Examples of Hadamard spaces are Hilbert spaces, the Poincaré disc, complete real trees (for example, complete Bruhat–Tits building), -space with and and Hadamard manifolds, that is, complete simply-connected Riemannian manifolds of nonpositive sectional curvature. Important exa
|
https://en.wikipedia.org/wiki/Application%20domain
|
An application domain is a mechanism (similar to a process in an operating system) used within the Common Language Infrastructure (CLI) to isolate executed software applications from one another so that they do not affect each other. Each application domain has its own virtual address space which scopes the resources for the application domain using that address space.
Creating multiple application domains in the same process is not possible in .NET Core and .NET 5+.
Properties
A CLI application domain is contained within an operating system process. A process may contain many application domains. Application domains have isolation properties similar to that of operating system processes:
Multiple threads can exist within a single application domain.
An application within a domain can be stopped without affecting the state of another domain in the same process.
A fault or exception in one domain does not affect an application in another domain or crash the entire process that hosts the domains.
Configuration information is part of a domain's scope, not the scope of the process.
Each domain can be assigned different security access levels.
Code in one domain cannot directly access code in another.
In this sense, a CLI is like a mini-operating system. It runs a single process that contains a number of sub-processes, or application domains.
The advantage of application domains is that running multiple application domains may require fewer resources, such as memory, than running multiple operating system processes. Communication between domains still requires marshalling, so the overheads can be closer to using multiple processes than to communicating within a single domain.
Inter-domain communications
Direct communication cannot be achieved across application domains. However, application domains can still talk to each other by passing objects via marshalling by value (unbound objects), marshalling by reference through a proxy (application-domain-bound objec
|
https://en.wikipedia.org/wiki/Clonal%20selection
|
In immunology, clonal selection theory explains the functions of cells of the immune system (lymphocytes) in response to specific antigens invading the body. The concept was introduced by Australian doctor Frank Macfarlane Burnet in 1957, in an attempt to explain the great diversity of antibodies formed during initiation of the immune response. The theory has become the widely accepted model for how the human immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens.
The theory states that in a pre-existing group of lymphocytes (both B and T cells
), a specific antigen activates (i.e. selects) only its counter-specific cell, which then induces that particular cell to multiply, producing identical clones for antibody production. This activation occurs in secondary lymphoid organs such as the spleen and the lymph nodes. In short, the theory is an explanation of the mechanism for the generation of diversity of antibody specificity. The first experimental evidence came in 1958, when Gustav Nossal and Joshua Lederberg showed that one B cell always produces only one antibody. The idea turned out to be the foundation of molecular immunology, especially in adaptive immunity.
Postulates
The clonal selection theory can be summarised with the following four tenets:
Each lymphocyte bears a single type of receptor with a unique specificity (generated by V(D)J recombination).
Receptor occupation is required for cell activation.
The differentiated effector cells derived from an activated lymphocyte bear receptors of identical specificity as the parent cell.
Those lymphocytes bearing receptors for self molecules (i.e., endogenous antigens produced within the body) are destroyed at an early stage.
Early work
In 1900, Paul Ehrlich proposed the so-called "side chain theory" of antibody production. According to it, certain cells exhibit on their surface different "side chains" (i.e. membrane-bound antibodie
|
https://en.wikipedia.org/wiki/Band%20clamp
|
A band clamp is a generic term for a holding device usually consisting of a strap of metal or cloth formed into a loop, with a mechanism to forcibly adjust the diameter, thereby exerting a squeezing force on an object within the loop.
One type of band clamp known as a web clamp has a band usually made of nylon type cloth webbing. It can slip and stretch around irregularly shaped objects such as frames, packages, skids or even trailer loads.
Clamping pressure is applied either through a mechanical method such as a screw or ratchet mechanism that tightens the band, or through the elastic nature of the band material itself. There are a range of styles of band clamp available for purchase, in particular the type used for framing as described above. Other web clamps include ratchet straps.
See also
Hose clamp
Jubilee clip
References
Clamps (tool)
Woodworking clamps
|
https://en.wikipedia.org/wiki/Microsoft%20Assistance%20Markup%20Language
|
Microsoft Assistance Markup Language (Microsoft AML, generally referred to as MAML) is an XML-based markup language developed by the Microsoft User Assistance Platform team to provide user assistance ("online help") for the Microsoft Windows Vista operating system. It makes up the Assistance Platform on Windows Vista.
MAML is also used to provide help information for PowerShell V2 Cmdlets, modules and advanced functions.
Concept
MAML is a departure from all previous types of user assistance for Windows operating systems. Some of its features have been available in .NET Framework 2, but more options shipped with the release of .NET Framework 3. Previously, user assistance for Windows operating systems used Microsoft Compiled HTML Help files, which contains little machine-readable semantic information.
The most significant aspect of MAML is that it shifts the production of user assistance to the concept of structured authoring (somewhat similar to DITA or DocBook). Documents and their constituent elements are defined by their context. With MAML, the emphasis is on content and the tasks a user performs with a computer, not the features of the software. Presentation is managed as part of the rendering engine when a user requests a topic.
The structured feature of MAML means that it can express a wide range of active concepts as well. One notable feature is guided help (active content wizard), which allows the help file to either run a task automatically or highlight the parts of the screen a user should interact with step-by-step. This feature was considered a highlight of Project Longhorn, but Microsoft decided against including it in the final Vista release.
The MAML authoring structure is divided into segments related to a type of content: conceptual, FAQ, glossary, procedure, reference, reusable content, task, troubleshooting, and tutorial.
Presentation
Three levels of transformation occur when a topic is displayed: structure, presentation, and rendering:
|
https://en.wikipedia.org/wiki/Purple%20fringing
|
In photography (particularly digital photography), purple fringing (sometimes called PF) is the term for an unfocused purple or magenta "ghost" image on a photograph. This optical aberration is generally most visible as a coloring and lightening of dark edges adjacent to bright areas of broad-spectrum illumination, such as daylight or various types of gas-discharge lamps.
Lenses in general exhibit axial chromatic aberration, in which different colors of light do not focus in the same plane. Normally, lens designs are optimized so that two or more (at least three for apochromatic lenses) wavelengths of light in the visible spectrum focus at the same plane. Wavelengths very different from those optimized in the design process may be severely out of focus while the reference colors are in focus; this axial chromatic aberration is usually severe at short wavelengths (violet). Lens performance may be poor for such wavelengths in other ways too, including an increase in flare due to anti-reflective coatings also being optimized for the expected wavelengths.
Most film has relatively low sensitivity to colors outside the visible range, so light spread in the near ultraviolet (UV) or near infrared (IR) rarely has a significant impact on the image recorded. However, image sensors used in digital cameras commonly are sensitive to a wider range of wavelengths . Although the lens glass itself filters out much of the UV light, and all digital cameras designed for color photography incorporate filters to reduce red and IR sensitivity , the chromatic aberration can be sufficient for unfocused violet light to tint nearby dark regions of the image . Bright cloudy or hazy skies are strong sources of scattered violet and UV light , so they tend to cause the problem.
The term purple fringe used to describe one aspect of chromatic aberration dates back to at least 1833.
However, Brewster's description with a purple fringe on one edge and a green fringe on the other is a lateral chroma
|
https://en.wikipedia.org/wiki/Pseudolocalization
|
Pseudolocalization (or pseudo-localization) is a software testing method used for testing internationalization aspects of software. Instead of translating the text of the software into a foreign language, as in the process of localization, the textual elements of an application are replaced with an altered version of the original language. For example, instead of "Account Settings", the text may be altered to display as "!!! Àççôûñţ Šéţţîñĝš !!!".
These specific alterations make the original words appear readable, but include the most problematic characteristics of the world's languages: varying length of text or characters, language direction, fit into the interface and so on.
Localization process
Traditionally, localization of software is independent of the software development process. In a typical scenario, software would be built and tested in one base language (such as English), with any localizable elements being extracted into external resources. Those resources are handed off to a localization team for translation into different target languages. The problem with this approach is that many subtle software bugs may be found during the process of localization, when it is too late (or more likely, too expensive) to fix them.
The types of problems that can arise during localization involve differences in how written text appears in different languages. These problems include:
Translated text that is significantly longer than the source language, and does not fit within the UI constraints, or which causes text breaks at awkward positions.
Font glyphs that are significantly larger than, or possess diacritic marks not found in, the source language, and which may be cut off vertically.
Languages for which the reading order is not left-to-right, which is especially problematic for user input.
Application code that assumes all characters fit into a limited character set, such as ASCII or ANSI, which can produce actual logic bugs if left uncaught.
In addit
|
https://en.wikipedia.org/wiki/Sodium%20bisulfate
|
Sodium bisulfate, also known as sodium hydrogen sulfate, is the sodium salt of the bisulfate anion, with the molecular formula NaHSO4. Sodium bisulfate is an acid salt formed by partial neutralization of sulfuric acid by an equivalent of sodium base, typically in the form of either sodium hydroxide (lye) or sodium chloride (table salt). It is a dry granular product that can be safely shipped and stored. The anhydrous form is hygroscopic. Solutions of sodium bisulfate are acidic, with a 1M solution having a pH of slightly below 1.
Production
Sodium bisulfate is produced as an intermediate in the Mannheim process, an industrial process involving the reaction of sodium chloride and sulfuric acid:
NaCl + H2SO4 → HCl + NaHSO4
The process for the formation of sodium bisulfate is highly exothermic. The liquid sodium bisulfate is sprayed and cooled so that it forms a solid bead. The hydrogen chloride gas is dissolved in water to produce hydrochloric acid as a useful coproduct of the reaction.
Sodium bisulfate can be generated as a byproduct of the production of many other mineral acids via the reaction of their sodium salts with an excess of sulfuric acid:
NaX + H2SO4 → NaHSO4 + HX ( X− = CN−, NO3−, ClO4−)
The acids HX produced have a lower boiling point than the reactants and are separated from the reaction mixture by distillation.
Chemical reactions
Hydrated sodium bisulfate dehydrates at at which point it separates from the water molecule attached to it. Once cooled again, it is freshly hygroscopic. Heating sodium bisulfate to produces sodium pyrosulfate, another colorless salt:
2 NaHSO4 → Na2S2O7 + H2O
Uses
Sodium bisulfate is used primarily to lower pH. it also is used in metal finishing, cleaning products, and to lower the pH of water for effective chlorination in swimming pools and hot tubs. Sodium bisulfate is also AAFCO approved as a general-use feed additive, including use in poultry feed and companion animal food. It is used as a urine acidifie
|
https://en.wikipedia.org/wiki/WalkSAT
|
In computer science, GSAT and WalkSAT are local search algorithms to solve Boolean satisfiability problems.
Both algorithms work on formulae in Boolean logic that are in, or have been converted into conjunctive normal form. They start by assigning a random value to each variable in the formula. If the assignment satisfies all clauses, the algorithm terminates, returning the assignment. Otherwise, a variable is flipped and the above is then repeated until all the clauses are satisfied. WalkSAT and GSAT differ in the methods used to select which variable to flip.
GSAT makes the change which minimizes the number of unsatisfied clauses in the new assignment, or with some probability picks a variable at random.
WalkSAT first picks a clause which is unsatisfied by the current assignment, then flips a variable within that clause. The clause is picked at random among unsatisfied clauses. The variable is picked that will result in the fewest previously satisfied clauses becoming unsatisfied, with some probability of picking one of the variables at random. When picking at random, WalkSAT is guaranteed at least a chance of one out of the number of variables in the clause of fixing a currently incorrect assignment. When picking a guessed-to-be-optimal variable, WalkSAT has to do less calculation than GSAT because it is considering fewer possibilities.
Both algorithms may restart with a new random assignment if no solution has been found for too long, as a way of getting out of local minima of numbers of unsatisfied clauses.
Many versions of GSAT and WalkSAT exist. WalkSAT has been proven particularly useful in solving satisfiability problems produced by conversion from automated planning problems. The approach to planning that converts planning problems into Boolean satisfiability problems is called satplan.
MaxWalkSAT is a variant of WalkSAT designed to solve the weighted satisfiability problem, in which each clause has associated with a weight, and the goal is to find
|
https://en.wikipedia.org/wiki/Backbone%20network
|
A backbone or core network is a part of a computer network which interconnects networks, providing a path for the exchange of information between different LANs or subnetworks. A backbone can tie together diverse networks in the same building, in different buildings in a campus environment, or over wide areas. Normally, the backbone's capacity is greater than the networks connected to it.
A large corporation that has many locations may have a backbone network that ties all of the locations together, for example, if a server cluster needs to be accessed by different departments of a company that are located at different geographical locations. The pieces of the network connections (for example: Ethernet, wireless) that bring these departments together is often mentioned as network backbone. Network congestion is often taken into consideration while designing backbones.
One example of a backbone network is the Internet backbone.
History
The theory, design principles, and first instantiation of the backbone network came from the telephone core network when traffic was purely voice. The core network was the central part of a telecommunications network that provided various services to customers who were connected by the access network. One of the main functions was to route telephone calls across the PSTN.
Typically the term referred to the high capacity communication facilities that connect primary nodes. A core network provided paths for the exchange of information between different sub-networks.
In the United States, local exchange core networks were linked by several competing interexchange networks; in the rest of the world, the core network has been extended to national boundaries.
Core networks usually had a mesh topology that provided any-to-any connections among devices on the network. Many main service providers would have their own core/backbone networks that are interconnected. Some large enterprises have their own core/backbone network, which are typ
|
https://en.wikipedia.org/wiki/Ambient%20space%20%28mathematics%29
|
In mathematics, especially in geometry and topology, an ambient space is the space surrounding a mathematical object along with the object itself. For example, a 1-dimensional line may be studied in isolation —in which case the ambient space of is , or it may be studied as an object embedded in 2-dimensional Euclidean space —in which case the ambient space of is , or as an object embedded in 2-dimensional hyperbolic space —in which case the ambient space of is . To see why this makes a difference, consider the statement "Parallel lines never intersect." This is true if the ambient space is , but false if the ambient space is , because the geometric properties of are different from the geometric properties of . All spaces are subsets of their ambient space.
See also
Configuration space
Geometric space
Manifold and ambient manifold
Submanifolds and Hypersurfaces
Riemannian manifolds
Ricci curvature
Differential form
References
Further reading
Geometry
Topology
|
https://en.wikipedia.org/wiki/Genetic%20use%20restriction%20technology
|
Genetic use restriction technology (GURT), also known as terminator technology or suicide seeds, is the name given to proposed methods for restricting the use of genetically modified crops by activating (or deactivating) some genes only in response to certain stimuli, especially to cause second generation seeds to be infertile. The development and application of GURTs is primarily an attempt by private sector agricultural breeders to increase the extent of protection on their innovations. The technology was originally developed under a cooperative research and development agreement between the Agricultural Research Service of the United States Department of Agriculture and Delta & Pine Land Company in the 1990s and is not yet commercially available.
GURT was first reported on by the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) to the UN Convention on Biological Diversity and discussed during the 8th Conference of the Parties to the United Nations Convention on Biological Diversity in Curitiba, Brazil, March 20–31, 2006.
Process
Because of the continued development of the technology and the continued protection of patents that develop it, many descriptions of GURT differ from others. Even so, the basic description of many GURTs are similar. The process is typically composed of four genetic components: a target gene, a promoter, a trait switch, and a genetic switch, sometimes with slightly different names in different papers.
For example, a typical GURT works similarly to as follows: a plant with GURT technology has a target gene in its DNA that expresses when activated by a promoter gene. However, it is separated from the gene by a blocker sequence that prevents the promoter from accessing the target. When the plant receives a given external input, a genetic switch in the plant takes the input, amplifies it, and converts it into a biological signal. When a trait switch receives the amplified signal, it creates an enzyme that cuts the
|
https://en.wikipedia.org/wiki/Multi-armed%20bandit
|
In probability theory and machine learning, the multi-armed bandit problem (sometimes called the K- or N-armed bandit problem) is a problem in which a fixed limited set of resources must be allocated between competing (alternative) choices in a way that maximizes their expected gain, when each choice's properties are only partially known at the time of allocation, and may become better understood as time passes or by allocating resources to the choice. This is a classic reinforcement learning problem that exemplifies the exploration–exploitation tradeoff dilemma. The name comes from imagining a gambler at a row of slot machines (sometimes known as "one-armed bandits"), who has to decide which machines to play, how many times to play each machine and in which order to play them, and whether to continue with the current machine or try a different machine. The multi-armed bandit problem also falls into the broad category of stochastic scheduling.
In the problem, each machine provides a random reward from a probability distribution specific to that machine, that is not known a-priori. The objective of the gambler is to maximize the sum of rewards earned through a sequence of lever pulls. The crucial tradeoff the gambler faces at each trial is between "exploitation" of the machine that has the highest expected payoff and "exploration" to get more information about the expected payoffs of the other machines. The trade-off between exploration and exploitation is also faced in machine learning. In practice, multi-armed bandits have been used to model problems such as managing research projects in a large organization, like a science foundation or a pharmaceutical company. In early versions of the problem, the gambler begins with no initial knowledge about the machines.
Herbert Robbins in 1952, realizing the importance of the problem, constructed convergent population selection strategies in "some aspects of the sequential design of experiments". A theorem, the Gittins ind
|
https://en.wikipedia.org/wiki/Vascularity
|
Vascularity, in bodybuilding, is the condition of having many highly visible, prominent, and often extensively-ramified superficial veins. The skin appears "thin"—sometimes virtually transparent—due to an extreme reduction of subcutaneous fat, allowing for maximum muscle definition.
Vascularity is enhanced by extremely low body fat (usually below 10%) and low retained water, as well as the muscle engorgement ("pump") and venous distension accentuated by the vigorous flexing and potentially hazardous Valsalva effect which characterize competitive posing. Genetics and androgenic hormones will affect vascularity, as will ambient temperature. Additionally, although some bodybuilders develop arterial hypertension from performance-enhancing substances and practices, "high" venous pressure—being an order of magnitude lower than that of arteries— neither causes nor is caused by vascularity. Some bodybuilders use topical vasodilators to increase blood flow to the skin as well. Although historically controversial, vascularity is a highly-sought-after aesthetic for many male bodybuilders, but less so for female bodybuilders, where the target aesthetic is relatively more towards aesthetic symmetry than extreme development.
Bodybuilders or athletes sometimes dehydrate themselves a few days before a competition or show to achieve this so-called "ripped," vascular look. Self-dehydration is not recommended by medical professionals, as the negative and sometimes-fatal effects of the resultant water-electrolyte imbalances are well documented.
References
Bodybuilding
Anatomy
Human surface anatomy
Cardiovascular system
Forearm
Veins
Circulatory system
|
https://en.wikipedia.org/wiki/Depletion-load%20NMOS%20logic
|
In integrated circuits, depletion-load NMOS is a form of digital logic family that uses only a single power supply voltage, unlike earlier NMOS (n-type metal-oxide semiconductor) logic families that needed more than one different power supply voltage. Although manufacturing these integrated circuits required additional processing steps, improved switching speed and the elimination of the extra power supply made this logic family the preferred choice for many microprocessors and other logic elements.
Depletion-mode n-type MOSFETs as load transistors allow single voltage operation and achieve greater speed than possible with pure enhancement-load devices. This is partly because the depletion-mode MOSFETs can be a better current source approximation than the simpler enhancement-mode transistor can, especially when no extra voltage is available (one of the reasons early PMOS and NMOS chips demanded several voltages).
The inclusion of depletion-mode NMOS transistors in the manufacturing process demanded additional manufacturing steps compared to the simpler enhancement-load circuits; this is because depletion-load devices are formed by increasing the amount of dopant in the load transistors channel region, in order to adjust their threshold voltage. This is normally performed using ion implantation.
Although the CMOS process replaced most NMOS designs during the 1980s, some depletion-load NMOS designs are still produced, typically in parallel with newer CMOS counterparts. One example of this is the Z84015 and Z84C15.
History and background
Following the invention of the MOSFET by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959, they demonstrated MOSFET technology in 1960. They fabricated both PMOS and NMOS devices with a 20µm process. However, the NMOS devices were impractical, and only the PMOS type were practical working devices.
In 1965, Chih-Tang Sah, Otto Leistiko and A.S. Grove at Fairchild Semiconductor fabricated several NMOS devices with channel len
|
https://en.wikipedia.org/wiki/Plantsman
|
A plantsman is an enthusiastic and knowledgeable gardener (amateur or professional), nurseryman or nurserywoman. "Plantsman" can refer to a male or female person, though the terms plantswoman, or even plantsperson, are sometimes used. The word is sometimes said to be synonymous with "botanist" or "horticulturist", but that would indicate a professional involvement, whereas "plantsman" reflects an attitude to (and perhaps even an obsession with) plants. A horticulturist may be a plantsman, but a plantsman is not necessarily a horticulturist.
Defining the word
In the first edition (June 1979) of The Plantsman (a specialist magazine, published by the Royal Horticultural Society from 1994 until June 2019, when it was announced that the title would be changed to The Plant Review), Sandra Raphael (then a senior editor in the Dictionary Department of the Oxford University Press) contributed a short article on the history and meaning of the word. Her first example came from an issue of the Gardeners' Chronicle of 1881, when it seemed to mean "A nurseryman, a florist" (in the early sense of "florist" as a grower and breeder of flowers, rather than the more recent meaning of someone who sells or arranges them). She added that a modern definition should point out that "plantsman"
"…is usually intended to mean a connoisseur of plants or an expert gardener."
In her article, Raphael also quotes botanist David McClintock (writing in the Botanical Society of the British Isles' BSBI News, December 1976) on how to distinguish a botanist from a plantsman, beginning with the simple definition:
"A plantsman is one who loves plants for their own sake and knows how to cherish them. This… concept… may include a botanist: it certainly includes a host of admirable amateurs who may not know what a chromosome looks like or what taxonomy means, but they know the growing plant, wild or cultivated, first-hand. To my mind they are the cream of those in the plant world, a fund of invaluable firs
|
https://en.wikipedia.org/wiki/Higher-order%20programming
|
Higher-order programming is a style of computer programming that uses software components, like functions, modules or objects, as values. It is usually instantiated with, or borrowed from, models of computation such as lambda calculus which make heavy use of higher-order functions. A programming language can be considered higher-order if components, such as procedures or labels, can be used just like data. For example, these elements could be used in the same way as arguments or values.
For example, in higher-order programming, one can pass functions as arguments to other functions and functions can be the return value of other functions (such as in macros or for interpreting). This style of programming is mostly used in functional programming, but it can also be very useful in object-oriented programming. A slightly different interpretation of higher-order programming in the context of object-oriented programming are higher order messages, which let messages have other messages as arguments, rather than functions.
Examples of languages supporting this are Wolfram Language, C#, Java, ECMAScript (ActionScript, JavaScript, JScript), F#, Haskell, Lisp (Common Lisp, Scheme, Clojure, others), Lua, Oz, Perl, PHP, Prolog, Python, Ruby, Smalltalk, Scala, ML, and Erlang.
See also
Prolog#Higher-order programming
Higher-order logic programming
References
External links
"Higher Order Programming" by Sjoerd Visscher (Uses JavaScript as example language)
Programming paradigms
|
https://en.wikipedia.org/wiki/Strongly%20correlated%20material
|
Strongly correlated materials are a wide class of compounds that include insulators and electronic materials, and show unusual (often technologically useful) electronic and magnetic properties, such as metal-insulator transitions, heavy fermion behavior, half-metallicity, and spin-charge separation. The essential feature that defines these materials is that the behavior of their electrons or spinons cannot be described effectively in terms of non-interacting entities. Theoretical models of the electronic (fermionic) structure of strongly correlated materials must include electronic (fermionic) correlation to be accurate. As of recently, the label quantum materials is also used to refer to strongly correlated materials, among others.
Transition metal oxides
Many transition metal oxides belong to this class which may be subdivided according to their behavior, e.g. high-Tc, spintronic materials, multiferroics, Mott insulators, spin Peierls materials, heavy fermion materials, quasi-low-dimensional materials, etc. The single most intensively studied effect is probably high-temperature superconductivity in doped cuprates, e.g. La2−xSrxCuO4. Other ordering or magnetic phenomena and temperature-induced phase transitions in many transition-metal oxides are also gathered under the term "strongly correlated materials."
Electronic structures
Typically, strongly correlated materials have incompletely filled d- or f-electron shells with narrow energy bands. One can no longer consider any electron in the material as being in a "sea" of the averaged motion of the others (also known as mean field theory). Each single electron has a complex influence on its neighbors.
The term strong correlation refers to behavior of electrons in solids that is not well-described (often not even in a qualitatively correct manner) by simple one-electron theories such as the local-density approximation (LDA) of density-functional theory or Hartree–Fock theory. For instance, the seemingly simple ma
|
https://en.wikipedia.org/wiki/Now%20TV%20%28Hong%20Kong%29
|
Now TV (also stylised as now TV) is a pay-TV service provider in Hong Kong operated by PCCW Media Limited, a wholly owned subsidiary of PCCW. Launched on 26 September 2003, its TV signal is transmitted with IPTV technology through HKT's fixed broadband network.
It no
N
provides 197 TV channels including 176 channels branded under now TV (32 channels in HD), 21 channels from TVB Network Vision (1 channel in HD), and over 30 video on demand categories.
Now TV is the largest pay-TV operator in Hong Kong in terms of number of subscribers, number of channels, number of HD channels and quantity of VOD contents. The word "Now" is abbreviated from "Network Of the World".
History and establishment
Launched in March 1998, PCCW's services included a wide range of information and entertainment, such as news, video-on-demand (VOD), music videos, home-shopping, home-banking and educational content. iTV had some 67,000 subscribers at the end of 2000.
Due to the liberalization of the pay-TV market by the HKSAR government in early July 2000, the then existing duopolists, iTV and i-Cable, were confronted with ferocious competition. With fewer subscribers and hence the decline in the revenue generated from iTV, the interactive television operation was terminated in the final quarter of 2002. Now Broadband pay-TV service was launched in September 2003 with 23 channels under the same umbrella company PCCW; iTV is thus commonly viewed as the predecessor of Now TV.
In December 2005, Now TV introduced a technology with connection speed up to 18 megabits per second (Mbit/s). At least 75% of the service area will be offered a service running up to 8Mbit/s. In addition, Video-On-Demand services were launched in January 2006.
Now TV subscribers have access to 136 channels.
Chronology
March 1998 Hong Kong Telecom commercially launched iTV
July 2000 Liberalisation of the pay-TV market
Last quarter of 2002 Termination of iTV
August 2003 Now TV was unveiled
September 2003 Now TV was offi
|
https://en.wikipedia.org/wiki/Demersal%20fish
|
Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone). They occupy the sea floors and lake beds, which usually consist of mud, sand, gravel or rocks. In coastal waters they are found on or near the continental shelf, and in deep waters they are found on or near the continental slope or along the continental rise. They are not generally found in the deepest waters, such as abyssal depths or on the abyssal plain, but they can be found around seamounts and islands. The word demersal comes from the Latin demergere, which means to sink.
Demersal fish are bottom feeders. They can be contrasted with pelagic fish which live and feed away from the bottom in the open water column.
Demersal fish fillets contain little fish oil (one to four per cent), whereas pelagic fish can contain up to 30 per cent.
Types
Demersal fish can be divided into two main types: strictly benthic fish which can rest on the sea floor, and benthopelagic fish which can float in the water column just above the sea floor.
Benthopelagic fish have neutral buoyancy, so they can float at depth without much effort, while strictly benthic fish are denser, with negative buoyancy so they can lie on the bottom without any effort. Most demersal fish are benthopelagic.
As with other bottom feeders, a mechanism to deal with substrate is often necessary. With demersal fish the sand is usually pumped out of the mouth through the gill slit. Most demersal fish exhibit a flat ventral region so as to more easily rest their body on the substrate. The exception may be the flatfish, which are laterally depressed but lie on their sides. Also, many exhibit what is termed an "inferior" mouth, which means that the mouth is pointed downwards; this is beneficial as their food is often below them in the substrate. Those bottom feeders with upward-pointing mouths, such as stargazers, tend to seize swimming prey.
Benthic fish
Benthic fish are denser than water, so they
|
https://en.wikipedia.org/wiki/Pipeline%20video%20inspection
|
Pipeline video inspection is a form of telepresence used to visually inspect the interiors of pipelines, plumbing systems, and storm drains. A common application is for a plumber to determine the condition of small diameter sewer lines and household connection drain pipes.
Older sewer lines of small diameter, typically , are made by the union of a number of short sections. The pipe segments may be made of cast iron, with to sections, but are more often made of vitrified clay pipe (VCP), a ceramic material, in , & sections. Each iron or clay segment will have an enlargement (a "bell") on one end to receive the end of the adjacent segment. Roots from trees and vegetation may work into the joins between segments and can be forceful enough to break open a larger opening in terra cotta or corroded cast iron. Eventually a root ball will form that will impede the flow and this may cleaned out by a cutter mechanism or plumber's snake and subsequently inhibited by use of a chemical foam - a rooticide.
With modern video equipment, the interior of the pipe may be inspected - this is a form of non-destructive testing. A small diameter collector pipe will typically have a cleanout access at the far end and will be several hundred feet long, terminating at a manhole. Additional collector pipes may discharge at this manhole and a pipe (perhaps of larger diameter) will carry the effluent to the next manhole, and so forth to a pump station or treatment plant.
Without regular inspection of public sewers, a significant amount of waste may accumulate unnoticed until the system fails. In order to prevent resulting catastrophic events such as pipe bursts and raw sewage flooding onto city streets, municipalities usually conduct pipeline video inspections as a precautionary measure.
Inspection equipment
Service truck
The service truck contains a power supply in the form of a small generator, a small air-conditioned compartment containing video monitoring and recording equipment,
|
https://en.wikipedia.org/wiki/Square%20antiprism
|
In geometry, the square antiprism is the second in an infinite family of antiprisms formed by an even-numbered sequence of triangle sides closed by two polygon caps. It is also known as an anticube.
If all its faces are regular, it is a semiregular polyhedron or uniform polyhedron.
A nonuniform D4-symmetric variant is the cell of the noble square antiprismatic 72-cell.
Points on a sphere
When eight points are distributed on the surface of a sphere with the aim of maximising the distance between them in some sense, the resulting shape corresponds to a square antiprism rather than a cube. Specific methods of distributing the points include, for example, the Thomson problem (minimizing the sum of all the reciprocals of distances between points), maximising the distance of each point to the nearest point, or minimising the sum of all reciprocals of squares of distances between points.
Molecules with square antiprismatic geometry
According to the VSEPR theory of molecular geometry in chemistry, which is based on the general principle of maximizing the distances between points, a square antiprism is the favoured geometry when eight pairs of electrons surround a central atom. One molecule with this geometry is the octafluoroxenate(VI) ion () in the salt nitrosonium octafluoroxenate(VI); however, the molecule is distorted away from the idealized square antiprism. Very few ions are cubical because such a shape would cause large repulsion between ligands; is one of the few examples.
In addition, the element sulfur forms octatomic S8 molecules as its most stable allotrope. The S8 molecule has a structure based on the square antiprism, in which the eight atoms occupy the eight vertices of the antiprism, and the eight triangle-triangle edges of the antiprism correspond to single covalent bonds between sulfur atoms.
In architecture
The main building block of the One World Trade Center (at the site of the old World Trade Center destroyed on September 11, 2001) has the sha
|
https://en.wikipedia.org/wiki/Electrodynamic%20tether
|
Electrodynamic tethers (EDTs) are long conducting wires, such as one deployed from a tether satellite, which can operate on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, or as motors, converting electrical energy to kinetic energy. Electric potential is generated across a conductive tether by its motion through a planet's magnetic field.
A number of missions have demonstrated electrodynamic tethers in space, most notably the TSS-1, TSS-1R, and Plasma Motor Generator (PMG) experiments.
Tether propulsion
As part of a tether propulsion system, craft can use long, strong conductors (though not all tethers are conductive) to change the orbits of spacecraft. It has the potential to make space travel significantly cheaper. When direct current is applied to the tether, it exerts a Lorentz force against the magnetic field, and the tether exerts a force on the vehicle. It can be used either to accelerate or brake an orbiting spacecraft.
In 2012 Star Technology and Research was awarded a $1.9 million contract to qualify a tether propulsion system for orbital debris removal.
Uses for ED tethers
Over the years, numerous applications for electrodynamic tethers have been identified for potential use in industry, government, and scientific exploration. The table below is a summary of some of the potential applications proposed thus far. Some of these applications are general concepts, while others are well-defined systems. Many of these concepts overlap into other areas; however, they are simply placed under the most appropriate heading for the purposes of this table. All of the applications mentioned in the table are elaborated upon in the Tethers Handbook. Three fundamental concepts that tethers possess, are gravity gradients, momentum exchange, and electrodynamics. Potential tether applications can be seen below:
ISS reboost
EDT has been proposed to maintain the ISS orbit and save the expense of chemical propellant re
|
https://en.wikipedia.org/wiki/Neural%20oscillation
|
Neural oscillations, or brainwaves, are rhythmic or repetitive patterns of neural activity in the central nervous system. Neural tissue can generate oscillatory activity in many ways, driven either by mechanisms within individual neurons or by interactions between neurons. In individual neurons, oscillations can appear either as oscillations in membrane potential or as rhythmic patterns of action potentials, which then produce oscillatory activation of post-synaptic neurons. At the level of neural ensembles, synchronized activity of large numbers of neurons can give rise to macroscopic oscillations, which can be observed in an electroencephalogram. Oscillatory activity in groups of neurons generally arises from feedback connections between the neurons that result in the synchronization of their firing patterns. The interaction between neurons can give rise to oscillations at a different frequency than the firing frequency of individual neurons. A well-known example of macroscopic neural oscillations is alpha activity.
Neural oscillations in humans were observed by researchers as early as 1924 (by Hans Berger). More than 50 years later, intrinsic oscillatory behavior was encountered in vertebrate neurons, but its functional role is still not fully understood. The possible roles of neural oscillations include feature binding, information transfer mechanisms and the generation of rhythmic motor output. Over the last decades more insight has been gained, especially with advances in brain imaging. A major area of research in neuroscience involves determining how oscillations are generated and what their roles are. Oscillatory activity in the brain is widely observed at different levels of organization and is thought to play a key role in processing neural information. Numerous experimental studies support a functional role of neural oscillations; a unified interpretation, however, is still lacking.
History
Richard Caton discovered electrical activity in the cerebra
|
https://en.wikipedia.org/wiki/Land%20description
|
In surveying and property law, a land description or legal description is a written statement that delineates the boundaries of a piece of real property. In the written transfer of real property, it is universally required that the instrument of conveyance (deed) include a written description of the property.
Legal land description
Canada
In many parts of Canada the original subdivision of crown land was done by township surveys. Different sizes of townships have been used (e.g. Québec's irregularly shaped cantons and Ontario's concession townships), but all were designed to provide rectangular farm lots within a defined rural community. The survey of a township was essentially a subdivision survey, because the plan of the township was registered and the lots (sometimes called sections) were numbered. The description of a whole lot for legal purposes is complete in the identification of the township and the lot within the township.
A legal land description in Manitoba, Saskatchewan, and Alberta would be defined by the Dominion Land Survey. For example, the village of Yarbo, Saskatchewan is located at the legal land description of SE-12-20-33-W1, which would be the South East quarter of Section 12, Township 20, Range 33, West of the first meridian.
A legal land description in British Columbia Fraser Valley Lower Mainland (Metro Vancouver) is defined by land surveys based out of New Westminster. Land in New Westminster Townsite corresponding to present day New Westminster is labelled as such while land outside the townsite is labelled as being in New Westminster District. The Main subdivisions are District Lots that represent parcel sales to settlers mostly in the time from 1860-1890. District lots are numbered from DL1 to over DL3,000. These District Lots are still represented on the cadastral maps of British Columbia. Later these lots would be subdivided to form blocks and residential lots. A typical address would thus indicate a lot number, a block range, and
|
https://en.wikipedia.org/wiki/Cooling%20curve
|
A cooling curve is a line graph that represents the change of phase of matter, typically from a gas to a solid or a liquid to a solid. The independent variable (X-axis) is time and the dependent variable (Y-axis) is temperature. Below is an example of a cooling curve used in castings.
The initial point of the graph is the starting temperature of the matter, here noted as the "pouring temperature". When the phase change occurs, there is a "thermal arrest"; that is, the temperature stays constant. This is because the matter has more internal energy as a liquid or gas than in the state that it is cooling to. The amount of energy required for a phase change is known as latent heat. The "cooling rate" is the slope of the cooling curve at any point.
Alloy have range of melting point. It solidifies as above. First, molten alloy reaches to liquidus temperature and then freezing range starts. At solidus temperature, molten alloys becomes solid.
References
Phase transitions
Thermodynamics
|
https://en.wikipedia.org/wiki/Louisa%20Gross%20Horwitz%20Prize
|
The Louisa Gross Horwitz Prize for Biology or Biochemistry is an annual prize awarded by Columbia University to a researcher or group of researchers who have made an outstanding contribution in basic research in the fields of biology or biochemistry.
The prize was established at the bequest of S. Gross Horwitz and is named to honor his mother, Louisa Gross Horwitz, the daughter of trauma surgeon Samuel D. Gross. The prize was first awarded in 1967.
As of October 2018, 51 (50%) of the 101 prize recipients have subsequently been awarded the Nobel Prize in Physiology or Medicine (40) or Chemistry (11). It is regarded as one of the important precursors of a future Nobel Prize award.
Recipients
1967 Luis Leloir (1970 Chemistry)
1968 Har Gobind Khorana (1968 Physiology or Medicine), Marshall Warren Nirenberg (1968 Physiology or Medicine)
1969 Max Delbrück (1969 Physiology or Medicine), Salvador E. Luria (1969 Physiology or Medicine)
1970 Albert Claude (1974 Physiology or Medicine), George E. Palade (1974 Physiology or Medicine), Keith R. Porter
1971 Hugh E. Huxley
1972 Stephen W. Kuffler
1973 Renato Dulbecco (1975 Physiology or Medicine), Harry Eagle, Theodore T. Puck
1974 Boris Ephrussi
1975 K. Sune D. Bergstrom (1982 Physiology or Medicine), Bengt Samuelsson (1982 Physiology or Medicine)
1976 Seymour Benzer, Charles Yanofsky
1977 Michael Heidelberger, Elvin A. Kabat, Henry G. Kunkel
1978 David Hubel (1981 Physiology of Medicine), Vernon Mountcastle, Torsten Wiesel (1981 Physiology or Medicine)
1979 Walter Gilbert (1980 Chemistry), Frederick Sanger (1980 Chemistry)
1980 César Milstein (1984 Physiology or Medicine)
1981 Aaron Klug (1982 Chemistry)
1982 Barbara McClintock (1983 Physiology or Medicine), Susumu Tonegawa (1987 Physiology or Medicine)
1983 Stanley Cohen (1986 Physiology or Medicine), Viktor Hamburger, Rita Levi-Montalcini (1986 Physiology or Medicine)
1984 Michael S. Brown (1985 Physiology or Medicine), Joseph L. Goldstein (1985 Physiology or Medicine)
1985
|
https://en.wikipedia.org/wiki/Linklog
|
A linklog is a type of blog which is meant to act as a linked list. Common practice is for the post titles to link directly to an external URLs, and the content of the post includes information to complement the associated URL.
Linklogs existed as a feature of computing systems before the internet as well. In distributed file systems a link log was a method of recording data in which a record is created and added to the proper log when updating a transaction. The format of a log record closely matches the specification of the transaction type it corresponds to. Link log records consisted of two parts in such a system: a set of type-independent fields, and a set of type-specific fields. The former set consists of pointers to the preceding and succeeding records of the log.
In PBX systems such as AUDIX link-logs were a collection of data collecting to assist operators in maintaining the system.
Linklog software
Linkwalla - A lightweight link blogging engine
Delicious, a social bookmarking web service - Now Defunct
See also
Microblogging
External links
The Ruby and Rails community linklog
Tony Finch's linklog
References
Internet terminology
Blogs
Computer-mediated communication
Internet culture
Information systems
Web syndication
Web syndication formats
|
https://en.wikipedia.org/wiki/Geometry%20%26%20Topology
|
Geometry & Topology is a peer-refereed, international mathematics research journal devoted to geometry and topology, and their applications. It is currently based at the University of Warwick, United Kingdom, and published by Mathematical Sciences Publishers, a nonprofit academic publishing organisation.
It was founded in 1997 by a group of topologists who were dissatisfied with recent substantial rises in subscription prices of journals published by major publishing corporations. The aim was to set up a high-quality journal, capable of competing with existing journals, but with substantially lower subscription fees. The journal was open-access for its first ten years of existence and was available free to individual users, although institutions were required to pay modest subscription fees for both online access and for printed volumes. At present, an online subscription is required to view full-text PDF copies of articles in the most recent three volumes; articles older than that are open-access, at which point copies of the published articles are uploaded to the arXiv. A traditional printed version is also published, at present on an annual basis.
The journal has grown to be well respected in its field, and has in recent years published a number of important papers, in particular proofs of the Property P conjecture and the Birman conjecture.
References
Walter Neumann on the Success of Geometry & Topology, May 2010, Sciencewatch.com, Thomson Reuters
External links
Geometry & Topology
MSP Open Access Policy
Mathematics journals
Academic journals established in 1997
English-language journals
Mathematical Sciences Publishers academic journals
|
https://en.wikipedia.org/wiki/Envelope%20%28motion%29
|
In mechanical engineering, an envelope is a solid representing all positions which may be occupied by an object during its normal range of motion.
Another (jargon) word for this is a "flop".
Wheel envelope
In automobile design, a wheel envelope may be used to model all positions a wheel and tire combo may be expected to occupy during driving. This will take into account the maximum jounce and rebound allowed by the suspension system and the maximum turn and tilt allowed by the steering mechanism. Minimum and maximum tire inflation pressures and wear conditions may also be considered when generating the envelope.
This envelope is then compared with the wheel housing and other components in the area to perform an interference/collision analysis. The results of this analysis tell the engineers whether that wheel/tire combo will strike the housing and components under normal driving conditions. If so, either a redesign is in order, or that wheel/tire combo will not be recommended.
A different wheel envelope must be generated for each wheel/tire combo for which the vehicle is rated. Much of this analysis is done using CAD/CAE systems running on computers. Of course, high speed collisions, during an accident, are not considered "normal driving conditions", so the wheel and tire may very well contact other parts of the vehicle at that time.
Robot's working envelope
In robotics, the working envelope or work area is the volume of working or reaching space. Some factors of a robot's design (configurations, axes or degrees of freedom) influence its working envelope.
References
Mechanical engineering
Robot control
|
https://en.wikipedia.org/wiki/List%20of%20rare%20species%20in%20the%20British%20National%20Vegetation%20Classification
|
The following is a list of vascular plants, bryophytes and lichens which were regarded as rare species by the authors of British Plant Communities, together with the communities in which they occur.
Vascular plants
Man orchid (Aceras anthropophorum) CG2, CG3, CG5
Baneberry (Actaea spicata) W9
Bristle bent (Agrostis curtisii) H2, H3, H4, H5, H6
Ground-pine (Ajuga chamaepitys) CG2, OV15
The lady's-mantle Alchemilla filicaulis ssp. filicaulis CG10
The lady's-mantle Alchemilla acutiloba MG3
The lady's-mantle Alchemilla glomerulans MG3
The lady's-mantle Alchemilla monticola MG3
The lady's-mantle Alchemilla subcrenata MG3
The lady's-mantle Alchemilla wichurae MG3, CG10
Babington's leek (Allium ampeloprasum var. babingtonii) OV6
Chives (Allium schoenoprasum) H6, H7, MC5
Three-cornered garlic (Allium triquetrum) OV24
Bog-rosemary (Andromeda polifolia) M2
Annual vernal-grass (Anthoxanthum aristatum) OV1
Loose silky-bent (Apera spica-venti) OV5
Bristol rock-cress (Arabis stricta) CG1
Field wormwood (Artemisia campestris) CG7
Goldilocks aster (Aster linosyris) CG1
Purple milk-vetch (Astragalus danicus) H7, CG2, CG3, CG4, CG5, CG7, SD11, SD12, MC10, MC5
Wild cabbage (Brassica oleracea) OV41, MC4, MC5
Lesser quaking-grass (Briza minor) OV1, OV2, OV6
Lesser hairy brome (Bromus benekenii) W9
Great pignut (Bunium bulbocastanum) CG2
Small hare's-ear (Bupleurum baldense) CG1
European box (Buxus sempervirens) W13
Narrow small-reed (Calamagrostis stricta) S1
Narrow-leaved bittercress (Cardamine impatiens) W8
Fibrous tussock-sedge (Carex appropinquata) W3
Hair sedge (Carex capillaris) CG10
String sedge (Carex chordorrhiza) M4
Lesser tussock-sedge (Carex diandra) W3
Elongated sedge (Carex elongata) W2
Rare spring-sedge (Carex ericetorum) CG2, CG5, CG7
Dwarf sedge (Carex humilis) CG1, CG2, CG3
Tall bog-sedge (Carex magellanica) M2
Soft-leaved sedge (Carex montana) H4, CG2, CG10
Rock sedge (Carex rupestris) CG10
Common centaury (Centaurium ery
|
https://en.wikipedia.org/wiki/Trembling%20hand%20perfect%20equilibrium
|
In game theory, trembling hand perfect equilibrium is a type of refinement of a Nash equilibrium that was first proposed by Reinhard Selten. A trembling hand perfect equilibrium is an equilibrium that takes the possibility of off-the-equilibrium play into account by assuming that the players, through a "slip of the hand" or tremble, may choose unintended strategies, albeit with negligible probability.
Definition
First define a perturbed game. A perturbed game is a copy of a base game, with the restriction that only totally mixed strategies are allowed to be played.
A totally mixed strategy is a mixed strategy where every strategy (both pure and mixed) is played with non-zero probability.
This is the "trembling hands" of the players; they sometimes play a different strategy, other than the one they intended to play. Then define a strategy set S (in a base game) as being trembling hand perfect if there is a sequence of perturbed games that converge to the base game in which there is a series of Nash equilibria that converge to S.
Note: All completely mixed Nash equilibria are perfect.
Note 2: The mixed strategy extension of any finite normal-form game has at least one perfect equilibrium.
Example
The game represented in the following normal form matrix has two pure strategy Nash equilibria, namely and . However, only is trembling-hand perfect.
Assume player 1 (the row player) is playing a mixed strategy , for .
Player 2's expected payoff from playing L is:
Player 2's expected payoff from playing the strategy R is:
For small values of , player 2 maximizes his expected payoff by placing a minimal weight on R and maximal weight on L. By symmetry, player 1 should place a minimal weight on D and maximal weight on U if player 2 is playing the mixed strategy . Hence is trembling-hand perfect.
However, similar analysis fails for the strategy profile .
Assume player 2 is playing a mixed strategy . Player 1's expected payoff from playing U is:
Player 1's
|
https://en.wikipedia.org/wiki/The%20Practice%20of%20Programming
|
The Practice of Programming () by Brian W. Kernighan and Rob Pike is a 1999 book about computer programming and software engineering, published by Addison-Wesley.
According to the preface, the book is about "topics like testing, debugging, portability, performance, design alternatives, and style", which, according to the authors, "are not usually the focus of computer science or programming courses". It treats these topics in case studies, featuring implementations in several programming languages (mostly C, but also C++, AWK, Perl, Tcl and Java).
The Practice of Programming has been translated into twelve languages. Eric S. Raymond, in The Art of Unix Programming, calls it "recommended reading for all C programmers (indeed for all programmers in any language)". A 2008 review on LWN.net found that TPOP "has aged well due to its focus on general principles" and that "beginners will benefit most but experienced developers will appreciate [...] the later chapters".
References
External links
Home page at Princeton
1999 non-fiction books
Addison-Wesley books
Computer programming books
Collaborative non-fiction books
Software engineering books
|
https://en.wikipedia.org/wiki/Hexagonal%20tiling
|
In geometry, the hexagonal tiling or hexagonal tessellation is a regular tiling of the Euclidean plane, in which exactly three hexagons meet at each vertex. It has Schläfli symbol of or (as a truncated triangular tiling).
English mathematician John Conway called it a hextille.
The internal angle of the hexagon is 120 degrees, so three hexagons at a point make a full 360 degrees. It is one of three regular tilings of the plane. The other two are the triangular tiling and the square tiling.
Applications
Hexagonal tiling is the densest way to arrange circles in two dimensions. The honeycomb conjecture states that hexagonal tiling is the best way to divide a surface into regions of equal area with the least total perimeter. The optimal three-dimensional structure for making honeycomb (or rather, soap bubbles) was investigated by Lord Kelvin, who believed that the Kelvin structure (or body-centered cubic lattice) is optimal. However, the less regular Weaire–Phelan structure is slightly better.
This structure exists naturally in the form of graphite, where each sheet of graphene resembles chicken wire, with strong covalent carbon bonds. Tubular graphene sheets have been synthesised, known as carbon nanotubes. They have many potential applications, due to their high tensile strength and electrical properties. Silicene is similar.
Chicken wire consists of a hexagonal lattice (often not regular) of wires.
The hexagonal tiling appears in many crystals. In three dimensions, the face-centered cubic and hexagonal close packing are common crystal structures. They are the densest sphere packings in three dimensions. Structurally, they comprise parallel layers of hexagonal tilings, similar to the structure of graphite. They differ in the way that the layers are staggered from each other, with the face-centered cubic being the more regular of the two. Pure copper, amongst other materials, forms a face-centered cubic lattice.
Uniform colorings
There are three distinct unif
|
https://en.wikipedia.org/wiki/Square%20tiling
|
In geometry, the square tiling, square tessellation or square grid is a regular tiling of the Euclidean plane. It has Schläfli symbol of meaning it has 4 squares around every vertex. Conway called it a quadrille.
The internal angle of the square is 90 degrees so four squares at a point make a full 360 degrees. It is one of three regular tilings of the plane. The other two are the triangular tiling and the hexagonal tiling.
Uniform colorings
There are 9 distinct uniform colorings of a square tiling. Naming the colors by indices on the 4 squares around a vertex: 1111, 1112(i), 1112(ii), 1122, 1123(i), 1123(ii), 1212, 1213, 1234. (i) cases have simple reflection symmetry, and (ii) glide reflection symmetry. Three can be seen in the same symmetry domain as reduced colorings: 1112i from 1213, 1123i from 1234, and 1112ii reduced from 1123ii.
Related polyhedra and tilings
This tiling is topologically related as a part of sequence of regular polyhedra and tilings, extending into the hyperbolic plane: {4,p}, p=3,4,5...
This tiling is also topologically related as a part of sequence of regular polyhedra and tilings with four faces per vertex, starting with the octahedron, with Schläfli symbol {n,4}, and Coxeter diagram , with n progressing to infinity.
Wythoff constructions from square tiling
Like the uniform polyhedra there are eight uniform tilings that can be based from the regular square tiling.
Drawing the tiles colored as red on the original faces, yellow at the original vertices, and blue along the original edges, all 8 forms are distinct. However treating faces identically, there are only three topologically distinct forms: square tiling, truncated square tiling, snub square tiling.
Topologically equivalent tilings
Other quadrilateral tilings can be made which are topologically equivalent to the square tiling (4 quads around every vertex).
Isohedral tilings have identical faces (face-transitivity) and vertex-transitivity, there are 18 variations, with
|
https://en.wikipedia.org/wiki/Triangular%20tiling
|
In geometry, the triangular tiling or triangular tessellation is one of the three regular tilings of the Euclidean plane, and is the only such tiling where the constituent shapes are not parallelogons. Because the internal angle of the equilateral triangle is 60 degrees, six triangles at a point occupy a full 360 degrees. The triangular tiling has Schläfli symbol of
English mathematician John Conway called it a deltille, named from the triangular shape of the Greek letter delta (Δ). The triangular tiling can also be called a kishextille by a kis operation that adds a center point and triangles to replace the faces of a hextille.
It is one of three regular tilings of the plane. The other two are the square tiling and the hexagonal tiling.
Uniform colorings
There are 9 distinct uniform colorings of a triangular tiling. (Naming the colors by indices on the 6 triangles around a vertex: 111111, 111112, 111212, 111213, 111222, 112122, 121212, 121213, 121314) Three of them can be derived from others by repeating colors: 111212 and 111112 from 121213 by combining 1 and 3, while 111213 is reduced from 121314.
There is one class of Archimedean colorings, 111112, (marked with a *) which is not 1-uniform, containing alternate rows of triangles where every third is colored. The example shown is 2-uniform, but there are infinitely many such Archimedean colorings that can be created by arbitrary horizontal shifts of the rows.
A2 lattice and circle packings
The vertex arrangement of the triangular tiling is called an A2 lattice. It is the 2-dimensional case of a simplectic honeycomb.
The A lattice (also called A) can be constructed by the union of all three A2 lattices, and equivalent to the A2 lattice.
+ + = dual of =
The vertices of the triangular tiling are the centers of the densest possible circle packing. Every circle is in contact with 6 other circles in the packing (kissing number). The packing density is or 90.69%.
The voronoi cell of a triangular tiling
|
https://en.wikipedia.org/wiki/List%20of%20constant%20species%20in%20the%20British%20National%20Vegetation%20Classification
|
The following is a list of vascular plants, bryophytes and lichens which are constant species in one or more community of the British National Vegetation Classification system.
Vascular plants
Grasses
Sedges and rushes
Trees
Other dicotyledons
Other monocotyledons
Ferns
Clubmosses
Bryophytes
Mosses
Liverworts
Lichens
British National Vegetation Classification
Lists of biota of the United Kingdom
British National Vegetation Classification, constant
|
https://en.wikipedia.org/wiki/Truncated%20hexagonal%20tiling
|
In geometry, the truncated hexagonal tiling is a semiregular tiling of the Euclidean plane. There are 2 dodecagons (12-sides) and one triangle on each vertex.
As the name implies this tiling is constructed by a truncation operation applies to a hexagonal tiling, leaving dodecagons in place of the original hexagons, and new triangles at the original vertex locations. It is given an extended Schläfli symbol of t{6,3}.
Conway calls it a truncated hextille, constructed as a truncation operation applied to a hexagonal tiling (hextille).
There are 3 regular and 8 semiregular tilings in the plane.
Uniform colorings
There is only one uniform coloring of a truncated hexagonal tiling. (Naming the colors by indices around a vertex: 122.)
Topologically identical tilings
The dodecagonal faces can be distorted into different geometries, such as:
Related polyhedra and tilings
Wythoff constructions from hexagonal and triangular tilings
Like the uniform polyhedra there are eight uniform tilings that can be based from the regular hexagonal tiling (or the dual triangular tiling).
Drawing the tiles colored as red on the original faces, yellow at the original vertices, and blue along the original edges, there are 8 forms, 7 which are topologically distinct. (The truncated triangular tiling is topologically identical to the hexagonal tiling.)
Symmetry mutations
This tiling is topologically related as a part of sequence of uniform truncated polyhedra with vertex configurations (3.2n.2n), and [n,3] Coxeter group symmetry.
Related 2-uniform tilings
Two 2-uniform tilings are related by dissected the dodecagons into a central hexagonal and 6 surrounding triangles and squares.
Circle packing
The truncated hexagonal tiling can be used as a circle packing, placing equal diameter circles at the center of every point. Every circle is in contact with 3 other circles in the packing (kissing number). This is the lowest density packing that can be created from a uniform tiling.
Triak
|
https://en.wikipedia.org/wiki/Truncated%20trihexagonal%20tiling
|
In geometry, the truncated trihexagonal tiling is one of eight semiregular tilings of the Euclidean plane. There are one square, one hexagon, and one dodecagon on each vertex. It has Schläfli symbol of tr{3,6}.
Names
Uniform colorings
There is only one uniform coloring of a truncated trihexagonal tiling, with faces colored by polygon sides. A 2-uniform coloring has two colors of hexagons. 3-uniform colorings can have 3 colors of dodecagons or 3 colors of squares.
Related 2-uniform tilings
The truncated trihexagonal tiling has three related 2-uniform tilings, one being a 2-uniform coloring of the semiregular rhombitrihexagonal tiling. The first dissects the hexagons into 6 triangles. The other two dissect the dodecagons into a central hexagon and surrounding triangles and square, in two different orientations.
Circle packing
The Truncated trihexagonal tiling can be used as a circle packing, placing equal diameter circles at the center of every point. Every circle is in contact with 3 other circles in the packing (kissing number).
Kisrhombille tiling
The kisrhombille tiling or 3-6 kisrhombille tiling is a tiling of the Euclidean plane. It is constructed by congruent 30-60-90 triangles with 4, 6, and 12 triangles meeting at each vertex.
Subdividing the faces of these tilings creates the kisrhombille tiling. (Compare the disdyakis hexa-, dodeca- and triacontahedron, three Catalan solids similar to this tiling.)
Construction from rhombille tiling
Conway calls it a kisrhombille for his kis vertex bisector operation applied to the rhombille tiling. More specifically it can be called a 3-6 kisrhombille, to distinguish it from other similar hyperbolic tilings, like 3-7 kisrhombille.
It can be seen as an equilateral hexagonal tiling with each hexagon divided into 12 triangles from the center point. (Alternately it can be seen as a bisected triangular tiling divided into 6 triangles, or as an infinite arrangement of lines in six parallel families.)
It is labeled
|
https://en.wikipedia.org/wiki/Truncated%20square%20tiling
|
In geometry, the truncated square tiling is a semiregular tiling by regular polygons of the Euclidean plane with one square and two octagons on each vertex. This is the only edge-to-edge tiling by regular convex polygons which contains an octagon. It has Schläfli symbol of t{4,4}.
Conway calls it a truncated quadrille, constructed as a truncation operation applied to a square tiling (quadrille).
Other names used for this pattern include Mediterranean tiling and octagonal tiling, which is often represented by smaller squares, and nonregular octagons which alternate long and short edges.
There are 3 regular and 8 semiregular tilings in the plane.
Uniform colorings
There are two distinct uniform colorings of a truncated square tiling. (Naming the colors by indices around a vertex (4.8.8): 122, 123.)
Circle packing
The truncated square tiling can be used as a circle packing, placing equal diameter circles at the center of every point. Every circle is in contact with 3 other circles in the packing (kissing number).
Variations
One variations on this pattern, often called a Mediterranean pattern, is shown in stone tiles with smaller squares and diagonally aligned with the borders. Other variations stretch the squares or octagons.
The Pythagorean tiling alternates large and small squares, and may be seen as topologically identical to the truncated square tiling. The squares are rotated 45 degrees and octagons are distorted into squares with mid-edge vertices.
A weaving pattern also has the same topology, with octagons flattened rectangles.
Related polyhedra and tilings
The truncated square tiling is topologically related as a part of sequence of uniform polyhedra and tilings with vertex figures 4.2n.2n, extending into the hyperbolic plane:
The 3-dimensional bitruncated cubic honeycomb projected into the plane shows two copies of a truncated tiling. In the plane it can be represented by a compound tiling, or combined can be seen as a chamfered square tiling.
|
https://en.wikipedia.org/wiki/Oblique%20reflection
|
In Euclidean geometry, oblique reflections generalize ordinary reflections by not requiring that reflection be done using perpendiculars. If two points are oblique reflections of each other, they will still stay so under affine transformations.
Consider a plane P in the three-dimensional Euclidean space. The usual reflection of a point A in space in respect to the plane P is another point B in space, such that the midpoint of the segment AB is in the plane, and AB is perpendicular to the plane. For an oblique reflection, one requires instead of perpendicularity that AB be parallel to a given reference line.
Formally, let there be a plane P in the three-dimensional space, and a line L in space not parallel to P. To obtain the oblique reflection of a point A in space in respect to the plane P, one draws through A a line parallel to L, and lets the oblique reflection of A be the point B on that line on the other side of the plane such that the midpoint of AB is in P. If the reference line L is perpendicular to the plane, one obtains the usual reflection.
For example, consider the plane P to be the xy plane, that is, the plane given by the equation z=0 in Cartesian coordinates. Let the direction of the reference line L be given by the vector (a, b, c), with c≠0 (that is, L is not parallel to P). The oblique reflection of a point (x, y, z) will then be
The concept of oblique reflection is easily generalizable to oblique reflection in respect to an affine hyperplane in Rn with a line again serving as a reference, or even more generally, oblique reflection in respect to a k-dimensional affine subspace, with a n−k-dimensional affine subspace serving as a reference. Back to three dimensions, one can then define oblique reflection in respect to a line, with a plane serving as a reference.
An oblique reflection is an affine transformation, and it is an involution, meaning that the reflection of the reflection of a point is the point itself.
References
Affine geometry
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.