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🔗 Spaceflight

The Nuclear Engine for Rocket Vehicle Application (NERVA) was a nuclear thermal rocket engine development program that ran for roughly two decades. Its principal objective was to "establish a technology base for nuclear rocket engine systems to be utilized in the design and development of propulsion systems for space mission application". It was a joint effort of the Atomic Energy Commission (AEC) and the National Aeronautics and Space Administration (NASA), and was managed by the Space Nuclear Propulsion Office (SNPO) until the program ended in January 1973. SNPO was led by NASA's Harold Finger and AEC's Milton Klein.

NERVA had its origins in Project Rover, an AEC research project at the Los Alamos Scientific Laboratory (LASL) with the initial aim of providing a nuclear-powered upper stage for the United States Air Force intercontinental ballistic missiles. Nuclear thermal rocket engines promised to be more efficient than chemical ones. After the formation of NASA in 1958, Project Rover was continued as a civilian project and was reoriented to producing a nuclear powered upper stage for NASA's Saturn V Moon rocket. Reactors were tested at very low power before being shipped to Jackass Flats in the Nevada Test Site. While LASL concentrated on reactor development, NASA built and tested complete rocket engines.

The AEC, SNPO, and NASA considered NERVA a highly successful program in that it met or exceeded its program goals. It demonstrated that nuclear thermal rocket engines were a feasible and reliable tool for space exploration, and at the end of 1968 SNPO deemed that the latest NERVA engine, the XE, met the requirements for a human mission to Mars. It had strong political support from Senators Clinton P. Anderson and Margaret Chase Smith but was cancelled by President Richard Nixon in 1973. Although NERVA engines were built and tested as much as possible with flight-certified components and the engine was deemed ready for integration into a spacecraft, they never flew in space.

🔗 United States 🔗 Germany 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Military history/Intelligence 🔗 United Kingdom 🔗 Military history/World War II 🔗 Military history/German military history 🔗 Military history/European military history 🔗 Military history/British military history

Operation Epsilon was the codename of a program in which Allied forces near the end of World War II detained ten German scientists who were thought to have worked on Nazi Germany's nuclear program. The scientists were captured between May 1 and June 30, 1945, as part of the Allied Alsos Mission, mainly as part of its Operation Big sweep through southwestern Germany.

They were interned at Farm Hall, a bugged house in Godmanchester, near Cambridge, England, from July 3, 1945, to January 3, 1946. The primary goal of the program was to determine how close Nazi Germany had been to constructing an atomic bomb by listening to their conversations.

🔗 Chess

Zugzwang (German for "compulsion to move", pronounced [ˈtsuːktsvaŋ]) is a situation found in chess and other turn-based games wherein one player is put at a disadvantage because they must make a move when they would prefer to pass and not move. The fact that the player is compelled to move means that their position will become significantly weaker. A player is said to be "in zugzwang" when any possible move will worsen their position.

Although the term is used less precisely in games such as chess, it is used specifically in combinatorial game theory to denote a move that directly changes the outcome of the game from a win to a loss. Putting the opponent in zugzwang is a common way to help the superior side win a game, and in some cases it is necessary in order to make the win possible.

The term zugzwang was used in German chess literature in 1858 or earlier, and the first known use of the term in English was by World Champion Emanuel Lasker in 1905. The concept of zugzwang was known to chess players many centuries before the term was coined, appearing in an endgame study published in 1604 by Alessandro Salvio, one of the first writers on the game, and in shatranj studies dating back to the early 9th century, over 1000 years before the first known use of the term.

Positions with zugzwang occur fairly often in chess endgames, especially in king and pawn endgames. According to John Nunn, positions of reciprocal zugzwang are surprisingly important in the analysis of endgames.

🔗 Religion 🔗 Bible 🔗 Linguistics

In corpus linguistics, a hapax legomenon ( also or ; pl. hapax legomena; sometimes abbreviated to hapax) is a word that occurs only once within a context, either in the written record of an entire language, in the works of an author, or in a single text. The term is sometimes incorrectly used to describe a word that occurs in just one of an author's works, but more than once in that particular work. Hapax legomenon is a transliteration of Greek ἅπαξ λεγόμενον, meaning "(something) being said (only) once".

The related terms dis legomenon, tris legomenon, and tetrakis legomenon respectively (, , ) refer to double, triple, or quadruple occurrences, but are far less commonly used.

Hapax legomena are quite common, as predicted by Zipf's law, which states that the frequency of any word in a corpus is inversely proportional to its rank in the frequency table. For large corpora, about 40% to 60% of the words are hapax legomena, and another 10% to 15% are dis legomena. Thus, in the Brown Corpus of American English, about half of the 50,000 distinct words are hapax legomena within that corpus.

Hapax legomenon refers to a word's appearance in a body of text, not to either its origin or its prevalence in speech. It thus differs from a nonce word, which may never be recorded, may find currency and may be widely recorded, or may appear several times in the work which coins it, and so on.

🔗 Computing 🔗 Computing/Software 🔗 Computing/Networking

The fallacies of distributed computing are a set of assertions made by L Peter Deutsch and others at Sun Microsystems describing false assumptions that programmers new to distributed applications invariably make.

🔗 Russia 🔗 Mathematics 🔗 Russia/science and education in Russia 🔗 Switzerland 🔗 Anthroponymy

In mathematics and physics, many topics are named in honor of Swiss mathematician Leonhard Euler (1707–1783), who made many important discoveries and innovations. Many of these items named after Euler include their own unique function, equation, formula, identity, number (single or sequence), or other mathematical entity. Many of these entities have been given simple and ambiguous names such as Euler's function, Euler's equation, and Euler's formula.

Euler's work touched upon so many fields that he is often the earliest written reference on a given matter. In an effort to avoid naming everything after Euler, some discoveries and theorems are attributed to the first person to have proved them after Euler.

🔗 Cryptography 🔗 Cryptography/Computer science 🔗 Poland

The method of Zygalski sheets was a cryptologic technique used by the Polish Cipher Bureau before and during World War II, and during the war also by British cryptologists at Bletchley Park, to decrypt messages enciphered on German Enigma machines.

The Zygalski-sheet apparatus takes its name from Polish Cipher Bureau mathematician–cryptologist Henryk Zygalski, who invented it about October 1938.

🔗 Spaceflight

StarTram is a proposed space launch system propelled by maglev. The initial Generation 1 facility would launch cargo only, launching from a mountain peak at an altitude of 3 to 7 kilometres (1.9 to 4.3 mi) with an evacuated tube staying at local surface level; it has been claimed that about 150,000 tons could be lifted to orbit annually. More advanced technology would be required for the Generation 2 system for passengers, with a longer track instead gradually curving up at its end to the thinner air at 22 kilometres (14 mi) altitude, supported by magnetic levitation, reducing g-forces when each capsule transitions from the vacuum tube to the atmosphere. A SPESIF 2010 presentation stated that Generation 1 could be completed by the year 2020 or later if funding began in 2010, and Generation 2 by 2030 or later.

🔗 United States/U.S. Government 🔗 United States 🔗 Human rights 🔗 Mass surveillance 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Freedom of speech 🔗 Military history/Intelligence 🔗 Law Enforcement

The practice of mass surveillance in the United States dates back to World War I wartime monitoring and censorship of international communications from, to, or which passed through the United States. After the First World War and the Second World War, the surveillance continued, via programs such as the Black Chamber and Project SHAMROCK. The formation and growth of federal law-enforcement and intelligence agencies such as the FBI, CIA, and NSA institutionalized surveillance used to also silence political dissent, as evidenced by COINTELPRO projects which targeted various organizations and individuals. During the Civil Rights Movement era, many individuals put under surveillance orders were first labelled as integrationists then deemed subversive. Other targeted individuals and groups included Native American activists, African American and Chicano liberation movement activists, and anti-war protesters.

The formation of the international UKUSA surveillance agreement of 1946 evolved into the ECHELON collaboration by 1955 of five English-speaking nations, also known as the Five Eyes, and focused on interception of electronic communications, with substantial increases in domestic surveillance capabilities.

Following the September 11th attacks of 2001, domestic and international mass surveillance capabilities grew immensely. Contemporary mass surveillance relies upon annual presidential executive orders declaring a continued State of National Emergency, first signed by George W. Bush on September 14, 2001 and then continued on an annual basis by President Barack Obama, and upon several subsequent national security Acts including the USA PATRIOT Act and FISA Amendment Act's PRISM surveillance program. Critics and political dissenters currently describe the effects of these acts, orders, and resulting database network of Fusion centers as forming a veritable American police state that simply institutionalized the illegal COINTELPRO tactics used to assassinate dissenters and leaders from the 1950s onwards.

Additional surveillance agencies, such as the DHS and the position of Director of National Intelligence have exponentially escalated mass surveillance since 2001. A series of media reports in 2013 revealed more recent programs and techniques employed by the US intelligence community. Advances in computer and information technology allow the creation of huge national databases that facilitate mass surveillance in the United States by DHS managed Fusion centers, the CIA's Terrorist Threat Integration Center (TTIC) program, and the FBI's TSDB.

Mass surveillance databases are also cited as responsible for profiling Latino Americans and contributing to "self-deportation" techniques, or physical deportations by way of the DHS's ICEGang national database.

After World War I, the US Army and State Department established the Black Chamber, also known as the Cipher Bureau, which began operations in 1919. The Black Chamber was headed by Herbert O. Yardley, who had been a leader in the Army's Military Intelligence program. Regarded as a precursor to the National Security Agency, it conducted peacetime decryption of material including diplomatic communications until 1929.

In the advent of World War II, the Office of Censorship was established. The wartime agency monitored "communications by mail, cable, radio, or other means of transmission passing between the United States and any foreign country". This included the 350,000 overseas cables and telegrams and 25,000 international telephone calls made each week. "Every letter that crossed international or U.S. territorial borders from December 1941 to August 1945 was subject to being opened and scoured for details."

With the end of World War II, Project SHAMROCK was established in 1945. The organization was created to accumulate telegraphic data entering and exiting from the United States. Major communication companies such as Western Union, RCA Global and ITT World Communications actively aided the project, allowing American intelligence officials to gain access to international message traffic. Under the project, and many subsequent programs, no precedent had been established for judicial authorisation, and no warrants were issued for surveillance activities. The project was terminated in 1975.

In 1952, President Harry S. Truman established the National Security Agency (NSA) in 1952 for the purposes of collecting, processing, and monitoring intelligence data. The existence of NSA was not known to people as the memorandum by President Truman was classified.

When the Citizens' Commission to Investigate the FBI published stolen FBI documents revealing abuse of intelligence programs in 1971, Senator Frank Church began an investigation into the programs that become known as the Church Committee. The committee sought to investigate intelligence abuses throughout the 1970s. Following a report provided by the committee outlining egregious abuse, in 1976 Congress established the Senate Select Committee on Intelligence. It would later be joined by the Foreign Intelligence Surveillance Court in 1978. The institutions worked to limit the power of the agencies, ensuring that surveillance activities remained within the rule of law.

Following the attacks of September 11, 2001, Congress passed The Patriot Act to strengthen security and intelligence efforts. The act granted the President broad powers on the war against terror, including the power to bypass the FISA Court for surveillance orders in cases of national security. Additionally, mass surveillance activities were conducted alongside various other surveillance programs under the head of President's Surveillance Program. Under pressure from the public, the warrantless wiretapping program was allegedly ended in January 2007.

Many details about the surveillance activities conducted in the United States were revealed in the disclosure by Edward Snowden in June 2013. Regarded as one of the biggest media leaks in the United States, it presented extensive details about the surveillance programs of the NSA, that involved interception of internet data and telephonic calls from over a billion users, across various countries.

🔗 Biography 🔗 Apple Inc. 🔗 Computing 🔗 Biography/science and academia 🔗 Disney

Alan Curtis Kay (born May 17, 1940) is an American computer scientist. He has been elected a Fellow of the American Academy of Arts and Sciences, the National Academy of Engineering, and the Royal Society of Arts. He is best known for his pioneering work on object-oriented programming and windowing graphical user interface (GUI) design.

He was the president of the Viewpoints Research Institute before its closure in 2018, and an adjunct professor of computer science at the University of California, Los Angeles. He is also on the advisory board of TTI/Vanguard. Until mid-2005, he was a senior fellow at HP Labs, a visiting professor at Kyoto University, and an adjunct professor at the Massachusetts Institute of Technology (MIT).

Kay is also a former professional jazz guitarist, composer, and theatrical designer, and an amateur classical pipe organist.