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🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military science, technology, and theory

The Fulton surface-to-air recovery system (STARS) is a system used by the Central Intelligence Agency (CIA), United States Air Force and United States Navy for retrieving persons on the ground using aircraft such as the MC-130E Combat Talon I and Boeing B-17. It involves using an overall-type harness and a self-inflating balloon with an attached lift line. An MC-130E engages the line with its V-shaped yoke and the person is reeled on board. Red flags on the lift line guide the pilot during daylight recoveries; lights on the lift line are used for night recoveries. Recovery kits were designed for one and two-man retrievals.

This system was developed by inventor Robert Edison Fulton, Jr., for the Central Intelligence Agency in the early 1950s. It was an evolution from a similar system that was used during World War II by American and British forces to retrieve both personnel and downed assault gliders following airborne operations. The earlier system did not use a balloon, but a line stretched between a pair of poles set in the ground on either side of the person to be retrieved. An aircraft, usually a C-47 Skytrain, trailed a grappling hook that engaged the line, which was attached to the person to be retrieved.

🔗 Mathematics

Gödel's completeness theorem is a fundamental theorem in mathematical logic that establishes a correspondence between semantic truth and syntactic provability in first-order logic. It makes a close link between model theory that deals with what is true in different models, and proof theory that studies what can be formally proven in particular formal systems.

It was first proved by Kurt Gödel in 1929. It was then simplified in 1947, when Leon Henkin observed in his Ph.D. thesis that the hard part of the proof can be presented as the Model Existence Theorem (published in 1949). Henkin's proof was simplified by Gisbert Hasenjaeger in 1953.

🔗 Internet 🔗 Internet culture 🔗 Economics 🔗 Sociology

Enshittification, also known as platform decay, is a way to describe the pattern of decreasing quality of online platforms that act as two-sided markets. Enshittification can be seen as a form of rent-seeking. Examples of alleged enshittification have included Google Search, Amazon, Bandcamp, Facebook, Reddit, and Twitter.

🔗 Game theory

Sprouts is a paper-and-pencil game that can be enjoyed simply by both adults and children. Yet it also can be analyzed for its significant mathematical properties. It was invented by mathematicians John Horton Conway and Michael S. Paterson at Cambridge University in the early 1960s. Setup is even simpler than the popular Dots and Boxes game, but game-play develops much more artistically and organically.

🔗 Computing 🔗 Computer science 🔗 Comedy

An esoteric programming language (sometimes shortened to esolang) is a programming language designed to test the boundaries of computer programming language design, as a proof of concept, as software art, as a hacking interface to another language (particularly functional programming or procedural programming languages), or as a joke. The use of esoteric distinguishes these languages from programming languages that working developers use to write software. Usually, an esolang's creators do not intend the language to be used for mainstream programming, although some esoteric features, such as visuospatial syntax, have inspired practical applications in the arts. Such languages are often popular among hackers and hobbyists.

Usability is rarely a goal for esoteric programming language designers—often the design leads to quite the opposite. Their usual aim is to remove or replace conventional language features while still maintaining a language that is Turing-complete, or even one for which the computational class is unknown.

🔗 Central Asia 🔗 Mining 🔗 Central Asia/Turkmenistan 🔗 Turkmenistan

The Darvaza gas crater (Turkmen: Garagum ýalkymy), also known as the Door to Hell or Gates of Hell, or, officially, the Shining of Karakum, is a burning natural gas field collapsed into a cavern near Darvaza, Turkmenistan. The floor and especially rim of the crater is illumined by hundreds of natural gas fires. The crater has been burning for an unknown amount of time, as how the crater formed and ignited remains unknown.

🔗 Statistics

Berkson's paradox also known as Berkson's bias or Berkson's fallacy is a result in conditional probability and statistics which is often found to be counterintuitive, and hence a veridical paradox. It is a complicating factor arising in statistical tests of proportions. Specifically, it arises when there is an ascertainment bias inherent in a study design. The effect is related to the explaining away phenomenon in Bayesian networks, and conditioning on a collider in graphical models.

It is often described in the fields of medical statistics or biostatistics, as in the original description of the problem by Joseph Berkson.

🔗 Biography 🔗 Science Fiction 🔗 Literature 🔗 Poland 🔗 Biography/arts and entertainment

Stanisław Herman Lem (Polish: [staˈɲiswaf ˈlɛm] (listen); 12 or 13 September 1921 – 27 March 2006) was a Polish writer of science fiction, philosophy, and satire. Lem's books have been translated into 41 languages and have sold over 45 million copies. From the 1950s to 2000s, he published many books, both science fiction and philosophical/futurological. Worldwide, he is best known as the author of the 1961 novel Solaris, which has been made into a feature film three times. In 1976, Theodore Sturgeon wrote that Lem was the most widely read science fiction writer in the world. The total print of Lem's books is over 30 million copies.

Lem's works explore philosophical themes through speculation on technology, the nature of intelligence, the impossibility of communication with and understanding of alien intelligence, despair about human limitations, and humanity's place in the universe. They are sometimes presented as fiction, but others are in the form of essays or philosophical books.

Translating his works is difficult due to passages with elaborate word formation, idiomatic wordplay, alien or robotic poetry, and puns.

🔗 Law Enforcement

SmartWater is a traceable liquid and forensic asset marking system (taggant) that is applied to items of value to identify thieves and deter theft. The liquid leaves a long lasting and unique identifier, whose presence is invisible except under an ultraviolet black light.

🔗 Sailing

The Vestas Sailrocket was built to capture the sailing speed record competing in the B-class for 150 to 235 square feet of sail. It is piloted by the project leader Paul Larsen and sponsored by Danish wind turbines manufacturer Vestas. In 2008 the first version reached a reported unofficial speed of 52.22 knots (96.71 km/h), before crashing.

After being upgraded to a second version, the Vestas Sailrocket 2 began a campaign to break speed records in November 2012 off Walvis Bay, Namibia. On 12 November, it made a 54.08 knots (100.16 km/h) run over a 500 metres (1,600 ft) distance, then 59.23 knots (109.69 km/h) on the 16th. It attained 55.32 knots (102.45 km/h) on a one-mile run on the 18th and simultaneously 59.38 knots (109.97 km/h) on 500m. On 24 November, with wind speeds at roughly 25 knots (46 km/h), it ran the 500m course at 65.45 knots (121.21 km/h) with a 68.01 knots (125.95 km/h) peak. Both records are ratified by the World Sailing Speed Record Council (WSSRC) for the 500m and the mile.

A Swiss team of École Polytechnique Fédérale de Lausanne university students and engineers, including members involved in the development of previous record-holder Hydroptère, formed in October 2019 to develop a new hydrofoil boat, SP80, to exceed the Vestas Sailrocket 2 record in 2022, with a target speed of 80 knots. As of April 2023, the speed record attempts were pushed back to 2024 and are scheduled to take place in Leucate.