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🔗 Computer science

The circle–ellipse problem in software development (sometimes called the square–rectangle problem) illustrates several pitfalls which can arise when using subtype polymorphism in object modelling. The issues are most commonly encountered when using object-oriented programming (OOP). By definition, this problem is a violation of the Liskov substitution principle, one of the SOLID principles.

The problem concerns which subtyping or inheritance relationship should exist between classes which represent circles and ellipses (or, similarly, squares and rectangles). More generally, the problem illustrates the difficulties which can occur when a base class contains methods which mutate an object in a manner which may invalidate a (stronger) invariant found in a derived class, causing the Liskov substitution principle to be violated.

The existence of the circle–ellipse problem is sometimes used to criticize object-oriented programming. It may also imply that hierarchical taxonomies are difficult to make universal, implying that situational classification systems may be more practical.

🔗 Germany 🔗 Archaeology 🔗 Visual arts 🔗 Fashion

The Berlin Gold Hat or Berlin Golden Hat (German: Berliner Goldhut) is a Late Bronze Age artefact made of thin gold leaf. It served as the external covering on a long conical brimmed headdress, probably of an organic material. It is now in the Neues Museum on Museum Island in Berlin, in a room by itself with an elaborate explanatory display.

The Berlin Gold Hat is the best preserved specimen among the four known conical golden hats known from Bronze Age Europe so far. Of the three others, two were found in southern Germany, and one in the west of France. All were found in the 19th and 20th centuries. It is generally assumed that the hats served as the insignia of deities or priests in the context of a sun cult that appears to have been widespread in Central Europe at the time. The hats are also suggested to have served astronomical/calendrical functions.

The Berlin Gold Hat was acquired in 1996 by the Berlin Museum für Vor- und Frühgeschichte as a single find without provenance. A comparative study of the ornaments and techniques in conjunction with dateable finds suggests that it was made in the Late Bronze Age, circa 1,000 to 800 BC.

🔗 Anthropology

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Military history/Russian, Soviet and CIS military history 🔗 Military history/Post-Cold War

The Poseidon (Russian: Посейдон, "Poseidon", NATO reporting name Kanyon), previously known by Russian codename Status-6 (Russian: Статус-6), is an autonomous, nuclear-powered, and nuclear-armed unmanned underwater vehicle under development by Rubin Design Bureau, capable of delivering both conventional and nuclear payloads.

The Poseidon is one of the six new Russian strategic weapons announced by Russian President Vladimir Putin on 1 March 2018.

Avram Noam Chomsky (born December 7, 1928) is an American professor and public intellectual known for his work in linguistics, political activism, and social criticism. Sometimes called "the father of modern linguistics", Chomsky is also a major figure in analytic philosophy and one of the founders of the field of cognitive science. He is a laureate professor of linguistics at the University of Arizona and an institute professor emeritus at the Massachusetts Institute of Technology (MIT). Among the most cited living authors, Chomsky has written more than 150 books on topics such as linguistics, war, and politics. Ideologically, he aligns with anarcho-syndicalism and libertarian socialism.

Born to Ashkenazi Jewish immigrants in Philadelphia, Chomsky developed an early interest in anarchism from alternative bookstores in New York City. He studied at the University of Pennsylvania. During his postgraduate work in the Harvard Society of Fellows, Chomsky developed the theory of transformational grammar for which he earned his doctorate in 1955. That year he began teaching at MIT, and in 1957 emerged as a significant figure in linguistics with his landmark work Syntactic Structures, which played a major role in remodeling the study of language. From 1958 to 1959 Chomsky was a National Science Foundation fellow at the Institute for Advanced Study. He created or co-created the universal grammar theory, the generative grammar theory, the Chomsky hierarchy, and the minimalist program. Chomsky also played a pivotal role in the decline of linguistic behaviorism, and was particularly critical of the work of B. F. Skinner.

An outspoken opponent of U.S. involvement in the Vietnam War, which he saw as an act of American imperialism, in 1967 Chomsky rose to national attention for his anti-war essay "The Responsibility of Intellectuals". Becoming associated with the New Left, he was arrested multiple times for his activism and placed on President Richard Nixon's list of political opponents. While expanding his work in linguistics over subsequent decades, he also became involved in the linguistics wars. In collaboration with Edward S. Herman, Chomsky later articulated the propaganda model of media criticism in Manufacturing Consent, and worked to expose the Indonesian occupation of East Timor. His defense of unconditional freedom of speech, including that of Holocaust denial, generated significant controversy in the Faurisson affair of the 1980s. Chomsky's commentary on the Cambodian genocide and the Bosnian genocide also generated controversy. Since retiring from active teaching at MIT, he has continued his vocal political activism, including opposing the 2003 invasion of Iraq and supporting the Occupy movement. An anti-Zionist, Chomsky considers Israel's treatment of Palestinians to be worse than South African-style apartheid, and criticizes U.S. support for Israel.

Chomsky is widely recognized as having helped to spark the cognitive revolution in the human sciences, contributing to the development of a new cognitivistic framework for the study of language and the mind. Chomsky remains a leading critic of U.S. foreign policy, contemporary capitalism, U.S. involvement and Israel's role in the Israeli–Palestinian conflict, and mass media. Chomsky and his ideas are highly influential in the anti-capitalist and anti-imperialist movements. Since 2017, he has been Agnese Helms Haury Chair in the Agnese Nelms Haury Program in Environment and Social Justice at the University of Arizona.

🔗 Anthropology 🔗 Archaeology 🔗 Yorkshire

The Heslington Brain is a 2,600-year-old human brain found inside a skull buried in a pit in Heslington, Yorkshire, in England, by York Archaeological Trust in 2008. It is the oldest preserved brain ever found in Eurasia, and is believed to be the best-preserved ancient brain in the world. The skull was discovered during an archaeological dig commissioned by the University of York on the site of its new campus on the outskirts of the city of York. The area was found to have been the site of well-developed permanent habitation between 2,000–3,000 years before the present day.

A number of possibly ritualistic objects were found to have been deposited in several pits, including the skull, which had belonged to a man probably in his 30s. He had been hanged before being decapitated with a knife and his skull appears to have been buried immediately. The rest of the body was missing. Although it is not known why he was killed, it is possible that it may have been a human sacrifice or ritual murder.

The brain was found while the skull was being cleaned. It had survived despite the rest of the tissue on the skull having disappeared long ago. After being extracted at York Hospital, the brain was subjected to a range of medical and forensic examinations by York Archaeological Trust which found that it was remarkably intact, though it had shrunk to only about 20% of its original size. It showed few signs of decay, though most of its original material had been replaced by an as yet unidentified organic compound, due to chemical changes during burial.

According to the archaeologists and scientists who have examined it, the brain has a "resilient, tofu-like texture". It is not clear why the Heslington brain survived, although the presence of a wet, anoxic environment underground seems to have been an essential factor, and research is still ongoing to shed light on how the local soil conditions may have contributed to its preservation.

🔗 Computing 🔗 Business 🔗 Computing/Software 🔗 Business/Accounting

Lotus 1-2-3 is a discontinued spreadsheet program from Lotus Software (later part of IBM). It was the first killer application of the IBM PC, was hugely popular in the 1980s, and significantly contributed to the success of IBM PC-compatibles in the business market.

The first spreadsheet, VisiCalc, had helped launch the Apple II as one of the earliest personal computers in business use. With IBM's entry into the market, VisiCalc was slow to respond, and when they did, they launched what was essentially a straight port of their existing system despite the greatly expanded hardware capabilities. Lotus's solution was marketed as a three-in-one integrated solution: it handled spreadsheet calculations, database functionality, and graphical charts, hence the name "1-2-3", though how much database capability the product actually had was debatable, given the sparse memory left over after launching 1-2-3. It quickly overtook VisiCalc, as well as Multiplan and SuperCalc, the two VisiCalc competitors.

Lotus 1-2-3 was the state-of-the-art spreadsheet and the standard throughout the 1980s and into the early 1990s, part of an unofficial set of three stand-alone office automation products that included dBase and WordPerfect, to build a complete business platform. Lotus Software had their own word processor named Lotus Manuscript, which was to some extent acclaimed in academia, but did not catch the interest of the business, nor the consumer market. With the acceptance of Windows 3.0 in 1990, the market for desktop software grew even more. None of the major spreadsheet developers had seriously considered the graphical user interface (GUI) to supplement their DOS offerings, and so they responded slowly to Microsoft's own GUI-based products Excel and Word. Lotus was surpassed by Microsoft in the early 1990s, and never recovered. IBM purchased Lotus in 1995, and continued to sell Lotus offerings, only officially ending sales in 2013.

🔗 United States 🔗 Film 🔗 Television 🔗 New York City 🔗 Library of Congress 🔗 Film/American cinema 🔗 United States/Film - American cinema 🔗 Film/Core 🔗 Television/Television stations 🔗 Film/Canadian cinema

Network is a 1976 American satirical black comedy-drama film released by Metro-Goldwyn-Mayer, written by Paddy Chayefsky and directed by Sidney Lumet. It is about a fictional television network, UBS, and its struggle with poor ratings. The film stars Faye Dunaway, William Holden, Peter Finch (in his final film role), Robert Duvall, Wesley Addy, Ned Beatty, and Beatrice Straight.

Network received widespread critical acclaim, with particular praise for the performances. The film was a commercial success, with nine Oscar nominations at the 49th Academy Awards, including Best Picture, that led to four wins: Best Actor (Finch), Best Actress (Dunaway), Best Supporting Actress (Straight), and Best Original Screenplay.

In 2000, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant". In 2002, it was inducted into the Producers Guild of America Hall of Fame as a film that has "set an enduring standard for American entertainment". In 2005, the two Writers Guilds of America voted Chayefsky's script one of the 10 greatest screenplays in the history of cinema. In 2007, the film was 64th among the 100 greatest American films as chosen by the American Film Institute, a ranking slightly higher than the one AFI had given it ten years earlier.

🔗 Mathematics

A prime number (or a prime) is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, 1 × 5 or 5 × 1, involve 5 itself. However, 6 is composite because it is the product of two numbers (2 × 3) that are both smaller than 6. Primes are central in number theory because of the fundamental theorem of arithmetic: every natural number greater than 1 is either a prime itself or can be factorized as a product of primes that is unique up to their order.

The property of being prime is called primality. A simple but slow method of checking the primality of a given number ${\displaystyle n}$, called trial division, tests whether ${\displaystyle n}$ is a multiple of any integer between 2 and ${\displaystyle {\sqrt {n}}}$. Faster algorithms include the Miller–Rabin primality test, which is fast but has a small chance of error, and the AKS primality test, which always produces the correct answer in polynomial time but is too slow to be practical. Particularly fast methods are available for numbers of special forms, such as Mersenne numbers. As of December 2018 the largest known prime number has 24,862,048 decimal digits.

There are infinitely many primes, as demonstrated by Euclid around 300 BC. No known simple formula separates prime numbers from composite numbers. However, the distribution of primes within the natural numbers in the large can be statistically modelled. The first result in that direction is the prime number theorem, proven at the end of the 19th century, which says that the probability of a randomly chosen number being prime is inversely proportional to its number of digits, that is, to its logarithm.

Several historical questions regarding prime numbers are still unsolved. These include Goldbach's conjecture, that every even integer greater than 2 can be expressed as the sum of two primes, and the twin prime conjecture, that there are infinitely many pairs of primes having just one even number between them. Such questions spurred the development of various branches of number theory, focusing on analytic or algebraic aspects of numbers. Primes are used in several routines in information technology, such as public-key cryptography, which relies on the difficulty of factoring large numbers into their prime factors. In abstract algebra, objects that behave in a generalized way like prime numbers include prime elements and prime ideals.

🔗 Radio

A crystal detector is an obsolete electronic component used in some early 20th century radio receivers that consists of a piece of crystalline mineral which rectifies the alternating current radio signal. It was employed as a detector (demodulator) to extract the audio modulation signal from the modulated carrier, to produce the sound in the earphones. It was the first type of semiconductor diode, and one of the first semiconductor electronic devices. The most common type was the so-called cat whisker detector, which consisted of a piece of crystalline mineral, usually galena (lead sulfide), with a fine wire touching its surface.

The "asymmetric conduction" of electric current across electrical contacts between a crystal and a metal was discovered in 1874 by Karl Ferdinand Braun. Crystals were first used as radio wave detectors in 1894 by Jagadish Chandra Bose in his microwave experiments. Bose first patented a crystal detector in 1901. The crystal detector was developed into a practical radio component mainly by G. W. Pickard, who began research on detector materials in 1902 and found hundreds of substances that could be used in forming rectifying junctions. The physical principles by which they worked were not understood at the time they were used, but subsequent research into these primitive point contact semiconductor junctions in the 1930s and 1940s led to the development of modern semiconductor electronics.

The unamplified radio receivers that used crystal detectors were called crystal radios. The crystal radio was the first type of radio receiver that was used by the general public, and became the most widely used type of radio until the 1920s. It became obsolete with the development of vacuum tube receivers around 1920, but continued to be used until World War II and remains a common educational project today thanks to its simple design.