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🔗 Computing

Refal ("[of] Recursive functions' algorithmic language") "is functional programming language oriented toward symbolic computations", including "string processing, language translation, [and] artificial intelligence". It is one of the oldest members of this family, first conceived of in 1966 as a theoretical tool, with the first implementation appearing in 1968. Refal was intended to combine mathematical simplicity with practicality for writing large and sophisticated programs.

One of the first functional programming languages to do so, and unlike Lisp of its time, Refal is based on pattern matching. Its pattern matching works in conjunction with term rewriting.

The basic data structure of Lisp and Prolog is a linear list built by cons operation in a sequential manner, thus with O(n) access to list's nth element. Refal's lists are built and scanned from both ends, with pattern matching working for nested lists as well as the top-level one. In effect, the basic data structure of Refal is a tree rather than a list. This gives freedom and convenience in creating data structures while using only mathematically simple control mechanisms of pattern matching and substitution.

Refal also includes a feature called the freezer to support efficient partial evaluation.

Refal can be applied to the processing and transformation of tree structures, similarly to XSLT.

The Leary–Lettvin debate was a May 3, 1967 debate between Dr. Jerome Lettvin, a medical doctor and professor at MIT, and Dr. Timothy Leary, a licensed psychologist, about the merits and dangers of the hallucinogenic drug LSD. It took place in the Kresge Auditorium at the Massachusetts Institute of Technology.

🔗 Greece 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Sicily 🔗 Greece/Byzantine world 🔗 Normandy

The term Norman–Arab–Byzantine culture, Norman–Sicilian culture or, less inclusively, Norman–Arab culture, (sometimes referred to as the "Arab-Norman civilization") refers to the interaction of the Norman, Byzantine Greek, Latin, and Arab cultures following the Norman conquest of the former Emirate of Sicily and North Africa from 1061 to around 1250. The civilization resulted from numerous exchanges in the cultural and scientific fields, based on the tolerance shown by the Normans towards the Latin- and Greek-speaking Christian populations and the former Arab Muslim settlers. As a result, Sicily under the Normans became a crossroad for the interaction between the Norman and Latin Catholic, Byzantine–Orthodox, and Arab–Islamic cultures.

🔗 Computing 🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Cryptography 🔗 Cryptography/Computer science 🔗 Poland 🔗 Computing/Early computers

The bomba, or bomba kryptologiczna (Polish for "bomb" or "cryptologic bomb"), was a special-purpose machine designed around October 1938 by Polish Cipher Bureau cryptologist Marian Rejewski to break German Enigma-machine ciphers.

In computer science, the ski rental problem is a name given to a class of problems in which there is a choice between continuing to pay a repeating cost or paying a one-time cost which eliminates or reduces the repeating cost.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Military history/World War II 🔗 Firearms 🔗 Military history/European military history 🔗 Military history/British military history

The Welrod is a British bolt-action, magazine-fed pistol with an integrated silencer which was devised for covert operations during the Second World War by Major Hugh Reeves at the Inter-Services Research Bureau (later Station IX).

Station IX, being based in Welwyn, gave the Welrod its unusual name, being derived from "Wel" from "Welwyn" (a prefix used by covert equipment designed by Station IX) and "rod", gangland slang for gun, as a way to obscure its purpose.

Designed for use by irregular forces and resistance groups, the Welrod is an extremely quiet gun thanks to its integrated silencer. Approximately 2,800 were made in wartime and perhaps 14,000 in total when post-war examples are included.

🔗 Lists 🔗 Sociology 🔗 Holidays 🔗 Organized Labour

In the majority of nations, including all industrialised nations except the United States, advances in employee relations have seen the introduction of statutory agreements for minimum employee leave from work—that is the amount of entitlement to paid vacation and public holidays. Several companies will offer contractually more time, depending on the sector. Companies and the law may also differ as to whether public holidays are counted as part of the minimum leave.

Disparities in national minimums are still subject of debate regarding work-life balance and perceived differences between nations. These numbers usually refer to full-time employment – part-time workers may get a reduced number of days. In most countries, public holidays are paid and usually not considered part of the annual leave. Also, in most countries there are additional paid leave benefits such as parental leave and sick leave that are not listed here.

🔗 Medicine 🔗 Maine

The Jumping Frenchmen of Maine were a group of 19th-century lumberjacks who exhibited a rare disorder of unknown origin. The syndrome entails an exaggerated startle reflex which may be described as an uncontrollable "jump"; individuals with this condition can exhibit sudden movements in all parts of the body. Jumping Frenchmen syndrome shares some symptoms with other startle disorders.

Individuals with this condition were first found in the Moosehead Lake region of Maine, and were first described by George Miller Beard in 1878.

🔗 Computing 🔗 Computing/Computer hardware

Viewtron was an online service offered by Knight-Ridder and AT&T from 1983 to 1986. Patterned after the British Post Office's Prestel system, it started as a videotex service requiring users to have a special terminal, the AT&T Sceptre. As home computers became important in the marketplace, the development focus shifted to IBM, Apple, Commodore and other personal computers.

Viewtron differed from contemporary services like CompuServe and The Source by emphasizing news from The Miami Herald and Associated Press and e-commerce services from JCPenney and other merchants over computer-oriented services such as file downloads or online chat. Intended to be "the McDonald's of videotex," Viewtron was specifically targeted toward users who would be apprehensive about using a computer.

Viewtron also offered airline schedules from the Official Airline Guide (OAG), real estate research from Century 21, e-cards from Hallmark, product information from Consumer Reports, educational software from Scott Foresman, online auctions, financial services from American Express and EF Hutton, as well as limited online banking services as part of a research program into the uses and costs of banking online that included 20 US and Canadian banks.

At its height, Viewtron was operated in at least 15 cities by various newspaper companies. After six years of research and an investment reportedly in excess of $50 million, Viewtron never turned a profit, and, despite its developer's forecasts of breaking even in two years, Knight Ridder did not expect it ever would be profitable. AT&T had invested over $100 million in the project, but was forced to write off that investment as part of its court-ordered breakup. Viewtron closed on March 31, 1986, after an attempt by the Independent Commodore Users Group to buy the service failed.

A feature tying Viewtron to local newspapers was envisioned, with printed text instructing users how to access further information online, but it was never implemented.

In 2008, PCWorld magazine named Viewtron to a list of the biggest project failures in information technology (IT) history.

🔗 Astronomy 🔗 Astronomy/Astronomical objects

Wolf 359 is a red dwarf star located in the constellation Leo, near the ecliptic. At a distance of approximately 7.9 light years from Earth, it has an apparent magnitude of 13.54 and can only be seen with a large telescope. Wolf 359 is one of the nearest stars to the Sun; only the Alpha Centauri system (including Proxima Centauri), Barnard's Star and the brown dwarfs Luhman 16 and WISE 0855−0714 are known to be closer. Its proximity to Earth has led to its mention in several works of fiction.

Wolf 359 is one of the faintest and lowest-mass stars known. At the light-emitting layer called the photosphere, it has a temperature of about 2,800 K, which is low enough for chemical compounds to form and survive. The absorption lines of compounds such as water and titanium(II) oxide have been observed in the spectrum. The surface has a magnetic field that is stronger than the average magnetic field on the Sun. As a result of magnetic activity caused by convection, Wolf 359 is a flare star that can undergo sudden increases in luminosity for several minutes. These flares emit strong bursts of X-ray and gamma ray radiation that have been observed by space telescopes. Wolf 359 is a relatively young star with an age of less than a billion years. Two planetary companions are suspected but as yet no debris disks have been unmasked.