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🔗 History of Science 🔗 Science

The frog galvanoscope was a sensitive electrical instrument used to detect voltage in the late eighteenth and nineteenth centuries. It consists of skinned frog's leg with electrical connections to a nerve. The instrument was invented by Luigi Galvani and improved by Carlo Matteucci.

The frog galvanoscope, and other experiments with frogs played a part in the dispute between Galvani and Alessandro Volta over the nature of electricity. The instrument is extremely sensitive and continued to be used well into the nineteenth century, even after electromechanical meters came into use.

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🔗 Video games

Core War is a 1984 programming game created by D. G. Jones and A. K. Dewdney in which two or more battle programs (called "warriors") compete for control of a virtual computer. These battle programs are written in an abstract assembly language called Redcode.

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.

🔗 Mathematics

The 15-puzzle (also called Gem Puzzle, Boss Puzzle, Game of Fifteen, Mystic Square and many others) is a sliding puzzle that consists of a frame of numbered square tiles in random order with one tile missing. The puzzle also exists in other sizes, particularly the smaller 8-puzzle. If the size is 3×3 tiles, the puzzle is called the 8-puzzle or 9-puzzle, and if 4×4 tiles, the puzzle is called the 15-puzzle or 16-puzzle named, respectively, for the number of tiles and the number of spaces. The object of the puzzle is to place the tiles in order by making sliding moves that use the empty space.

The n-puzzle is a classical problem for modelling algorithms involving heuristics. Commonly used heuristics for this problem include counting the number of misplaced tiles and finding the sum of the taxicab distances between each block and its position in the goal configuration. Note that both are admissible, i.e. they never overestimate the number of moves left, which ensures optimality for certain search algorithms such as A*.

🔗 England 🔗 Food and drink

English coffeehouses in the 17th and 18th centuries were public social places where men would meet for conversation and commerce. For the price of a penny, customers purchased a cup of coffee and admission. Travellers introduced coffee as a beverage to England during the mid-17th century; previously it had been consumed mainly for its supposed medicinal properties. Coffeehouses also served tea and hot chocolate as well as a light meal.

The historian Brian Cowan describes English coffeehouses as "places where people gathered to drink coffee, learn the news of the day, and perhaps to meet with other local residents and discuss matters of mutual concern." Topics like the Yellow Fever would also be discussed. The absence of alcohol created an atmosphere in which it was possible to engage in more serious conversation than in an alehouse. Coffeehouses also played an important role in the development of financial markets and newspapers.

Topics discussed included politics and political scandals, daily gossip, fashion, current events, and debates surrounding philosophy and the natural sciences. Historians often associate English coffeehouses, during the 17th and 18th centuries, with the intellectual and cultural history of the Age of Enlightenment: they were an alternate sphere, supplementary to the university. Political groups frequently used coffeehouses as meeting places.

🔗 Technology 🔗 Computing 🔗 Computer science 🔗 Systems 🔗 Business 🔗 Computing/Software 🔗 Systems/Software engineering

A fourth-generation programming language (4GL) is any computer programming language that belongs to a class of languages envisioned as an advancement upon third-generation programming languages (3GL). Each of the programming language generations aims to provide a higher level of abstraction of the internal computer hardware details, making the language more programmer-friendly, powerful, and versatile. While the definition of 4GL has changed over time, it can be typified by operating more with large collections of information at once rather than focusing on just bits and bytes. Languages claimed to be 4GL may include support for database management, report generation, mathematical optimization, GUI development, or web development. Some researchers state that 4GLs are a subset of domain-specific languages.

The concept of 4GL was developed from the 1970s through the 1990s, overlapping most of the development of 3GL, with 4GLs identified as "non-procedural" or "program-generating" languages, contrasted with 3GLs being algorithmic or procedural languages. While 3GLs like C, C++, C#, Java, and JavaScript remain popular for a wide variety of uses, 4GLs as originally defined found uses focused on databases, reports, and websites. Some advanced 3GLs like Python, Ruby, and Perl combine some 4GL abilities within a general-purpose 3GL environment, and libraries with 4GL-like features have been developed as add-ons for most popular 3GLs, producing languages that are a mix of 3GL and 4GL, blurring the distinction.

In the 1980s and 1990s, there were efforts to develop fifth-generation programming languages (5GL).

🔗 Caribbean 🔗 Football 🔗 Caribbean/Barbados 🔗 Grenada

On January 27, 1994, the national football teams of Barbados and Grenada played against each other as part of the qualification round for the 1994 Caribbean Cup. Barbados won 4-2 in extra time. In the last minutes of regular time, both teams attempted to score own goals. The result has been described as "one of the strangest matches ever".

In the 1994 Caribbean Cup, the tournament organisers implemented a variant of the golden goal rule: the first goal scored in extra-time not only won the match, but was also worth two goals. Barbados needed to win the match by a margin of at least two goals to qualify for the final tournament over Grenada. Barbados led the game 2-0 until Grenada scored at the 83rd minute, bringing the score to 2-1. Barbados then deliberately scored an own goal, tying the game at 2-2, to force extra-time so that they could take advantage of the golden goal rule to achieve their needed two-goal margin. This resulted in an unusual situation: for the last three minutes of the match, Grenada tried to score in both goals. Either outcome (3–2 on points, or 2–3 via goal difference) would have advanced them to the finals, while Barbados had to defend both goals. Ultimately, Barbados was able to prevent Grenada from scoring, forcing extra-time. Barbados then scored the golden goal to win the match.

The outcome of the match was criticised by Grenadian coach James Clarkson, who felt that his team had been unfairly prevented from advancing to the finals. However, given the fact that the unusual tournament rules had not been broken, FIFA cleared Barbados of any wrongdoing.

🔗 Mathematics

In geometric topology, the Clifford torus is the simplest and most symmetric flat embedding of the cartesian product of two circles S¹_a and S¹_b (in the same sense that the surface of a cylinder is "flat"). It is named after William Kingdon Clifford. It resides in R⁴, as opposed to in R³. To see why R⁴ is necessary, note that if S¹_a and S¹_b each exist in their own independent embedding spaces R²_a and R²_b, the resulting product space will be R⁴ rather than R³. The historically popular view that the cartesian product of two circles is an R³ torus in contrast requires the highly asymmetric application of a rotation operator to the second circle, since that circle will only have one independent axis z available to it after the first circle consumes x and y.

Stated another way, a torus embedded in R³ is an asymmetric reduced-dimension projection of the maximally symmetric Clifford torus embedded in R⁴. The relationship is similar to that of projecting the edges of a cube onto a sheet of paper. Such a projection creates a lower-dimensional image that accurately captures the connectivity of the cube edges, but also requires the arbitrary selection and removal of one of the three fully symmetric and interchangeable axes of the cube.

If S¹_a and S¹_b each has a radius of ${\displaystyle \textstyle {\sqrt {1/2}}}$, their Clifford torus product will fit perfectly within the unit 3-sphere S³, which is a 3-dimensional submanifold of R⁴. When mathematically convenient, the Clifford torus can be viewed as residing inside the complex coordinate space C², since C² is topologically equivalent to R⁴.

The Clifford torus is an example of a square torus, because it is isometric to a square with opposite sides identified. It is further known as a Euclidean 2-torus (the "2" is its topological dimension); figures drawn on it obey Euclidean geometry as if it were flat, whereas the surface of a common "doughnut"-shaped torus is positively curved on the outer rim and negatively curved on the inner. Although having a different geometry than the standard embedding of a torus in three-dimensional Euclidean space, the square torus can also be embedded into three-dimensional space, by the Nash embedding theorem; one possible embedding modifies the standard torus by a fractal set of ripples running in two perpendicular directions along the surface.