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🔗 English Language

Hello is a salutation or greeting in the English language. It is first attested in writing from 1826.

🔗 Computing 🔗 Computing/Software

Crash-only software refers to computer programs that handle failures by simply restarting, without attempting any sophisticated recovery. Correctly written components of crash-only software can microreboot to a known-good state without the help of a user. Since failure-handling and normal startup use the same methods, this can increase the chance that bugs in failure-handling code will be noticed, except when there are leftover artifacts, such as data corruption from a severe failure, that don't occur during normal startup.

Crash-only software also has benefits for end-users. All too often, applications do not save their data and settings while running, only at the end of their use. For example, word processors usually save settings when they are closed. A crash-only application is designed to save all changed user settings soon after they are changed, so that the persistent state matches that of the running machine. No matter how an application terminates (be it a clean close or the sudden failure of a laptop battery), the state will persist.

🔗 Religion 🔗 Christianity 🔗 Israel 🔗 Palestine 🔗 Christianity/Catholicism 🔗 Christianity/Eastern Orthodoxy 🔗 Christianity/Jesus 🔗 Christianity/Oriental Orthodoxy

The Immovable Ladder is a wooden ladder leaning against the right window on the second tier of the facade of the Church of the Holy Sepulchre in the Old City of Jerusalem. The ladder rests on a ledge and is attached to a window owned by the Armenian Apostolic Church. The ladder is a symbol of inter-confessional disputes within Christianity. Its presence in its current location signifies the adherence to an agreement among six Christian denominations, who collectively own the church, not to move, repair, or alter anything in the church without the consent of all six denominations.

🔗 Mathematics

The Basel problem is a problem in mathematical analysis with relevance to number theory, first posed by Pietro Mengoli in 1650 and solved by Leonhard Euler in 1734, and read on 5 December 1735 in The Saint Petersburg Academy of Sciences. Since the problem had withstood the attacks of the leading mathematicians of the day, Euler's solution brought him immediate fame when he was twenty-eight. Euler generalised the problem considerably, and his ideas were taken up years later by Bernhard Riemann in his seminal 1859 paper "On the Number of Primes Less Than a Given Magnitude", in which he defined his zeta function and proved its basic properties. The problem is named after Basel, hometown of Euler as well as of the Bernoulli family who unsuccessfully attacked the problem.

The Basel problem asks for the precise summation of the reciprocals of the squares of the natural numbers, i.e. the precise sum of the infinite series:

${\displaystyle \sum _{n=1}^{\infty }{\frac {1}{n^{2}}}={\frac {1}{1^{2}}}+{\frac {1}{2^{2}}}+{\frac {1}{3^{2}}}+\cdots .}$

The sum of the series is approximately equal to 1.644934. The Basel problem asks for the exact sum of this series (in closed form), as well as a proof that this sum is correct. Euler found the exact sum to be π²/6 and announced this discovery in 1735. His arguments were based on manipulations that were not justified at the time, although he was later proven correct, and it was not until 1741 that he was able to produce a truly rigorous proof.

🔗 Military history 🔗 Military history/Intelligence

The analysis of competing hypotheses (ACH) is a methodology for evaluating multiple competing hypotheses for observed data. It was developed by Richards (Dick) J. Heuer, Jr., a 45-year veteran of the Central Intelligence Agency, in the 1970s for use by the Agency. ACH is used by analysts in various fields who make judgments that entail a high risk of error in reasoning. ACH aims to help an analyst overcome, or at least minimize, some of the cognitive limitations that make prescient intelligence analysis so difficult to achieve.

ACH was a step forward in intelligence analysis methodology, but it was first described in relatively informal terms. Producing the best available information from uncertain data remains the goal of researchers, tool-builders, and analysts in industry, academia and government. Their domains include data mining, cognitive psychology and visualization, probability and statistics, etc. Abductive reasoning is an earlier concept with similarities to ACH.

🔗 United States 🔗 Donald Trump 🔗 Taiwan

The Trump–Tsai call was a telephone conversation between the U.S President-elect Donald Trump and the President of Taiwan Tsai Ing-wen which took place on December 2, 2016. This event marked the first time since 1979 that a U.S. president or President-elect had directly spoken with a ROC President. In the call, Tsai congratulated Trump for his victory in the presidential election. The two leaders spoke for around 10 minutes, focusing on politics, economy, and security in Asia-Pacific. Following the call, Trump publicized this on Twitter and Facebook and said thank you to "the President of Taiwan". After Trump's transition team confirmed the event, the Presidential Office of Taiwan released a statement about the content of the call.

Several prominent Republicans praised the call between the two leaders, saying that the United States needs no more pressure from the government of the People's Republic of China (commonly called "China"), which does not recognize the ROC government and claims Taiwan is part of its territory. Some commentators from U.S. media outlets said that the call humiliated Beijing as it seemed a violation of a diplomatic practice. Other media and comments criticized the One-China policy, saying that Trump's move was morally right and strategically correct for American interests. Wang Yi, the Foreign Minister of the People's Republic of China subsequently responded that this event is only a "small trick" played by Taiwan and will not change the One-China Policy. A spokesperson for the Presidential Office in Taipei expressed that there is no conflict between the Cross-Strait relations and the Taiwan–U.S. relations. The Obama administration stated that the U.S. would uphold the One-China Policy. Trump later responded by saying that the U.S. did not have to follow that policy.

🔗 Aviation 🔗 Disaster management 🔗 Aviation/Aviation accident 🔗 Canada 🔗 Aviation/aircraft 🔗 Aviation/gliding 🔗 Canada/History of Canada 🔗 Canada/Manitoba

Air Canada Flight 143 was a Canadian scheduled domestic passenger flight between Montreal and Edmonton that ran out of fuel on July 23, 1983, at an altitude of 41,000 feet (12,000 m), midway through the flight. The crew was able to glide the Boeing 767 aircraft safely to an emergency landing at a former Royal Canadian Air Force base in Gimli, Manitoba, that had been turned into a motor racing track. This unusual aviation incident earned the aircraft the nickname "Gimli Glider".

The subsequent investigation revealed that a combination of company failures, human errors and confusion over unit measures had led to the aircraft being refuelled with insufficient fuel for the planned flight.

🔗 Education 🔗 Organizations

The University of the Third Age is an international movement whose aims are the education and stimulation of mainly retired members of the community—those in their third 'age' of life. It is commonly referred to as U3A.

There is no universally accepted model for the U3A. Its original conception in France as an extramural university activity was significantly modified in the United Kingdom where it was recognized that most people of retirement age have something to contribute and the emphasis has been on sharing, without formal links to traditional universities.

Many English-speaking countries have followed this geragogic model, whereas continental European countries have mostly followed the French model. For historical reasons, Lifelong learning institutes is the term used in the United States for organizations that are similar to U3A groups.

A British U3A website reports this about "The Third Age" membership eligibility: "U3A membership is not related to a specific age but to a period in one’s life (the third age) after the second age of full-time employment and parental responsibility. Anybody in their third age can join U3A and this includes people who are working part-time. There is no lower age for membership."

🔗 Physics

In quantum field theory, a false vacuum is a hypothetical vacuum that is relatively stable, but not in the most stable state possible. In this condition it is called metastable. It may last for a very long time in this state, but could eventually decay to the more stable one, an event known as false vacuum decay. The most common suggestion of how such a decay might happen in our universe is called bubble nucleation – if a small region of the universe by chance reached a more stable vacuum, this "bubble" (also called "bounce") would spread.

A false vacuum exists at a local minimum of energy and is therefore not completely stable, in contrast to a true vacuum, which exists at a global minimum and is stable.

🔗 Video games 🔗 Marketing & Advertising

A feelie is a physical item included to supplement a video game. Likely deriving their name from the fictional media in Aldous Huxley's 1932 novel Brave New World, feelies were popularized by the American video game company Infocom in the 1980s and subsequently adopted by such companies as Origin Systems and Sierra Entertainment in the United States and Namco and ASCII in Japan. Becoming less prevalent since the rise of digital distribution, feelies are now limited primarily to deluxe editions that are sold at a premium.

Feelies may take various forms, with common ones including reproductions of game objects, printed materials, cosmetics, and figurines. Historically, feelies allowed video game developers to implement copy protection and minimize the amount of digital space used for supplemental materials while simultaneously distinguishing their products from those of competitors. For players, feelies could provide assistance during gameplay, opportunities for continued play elsewhere, and improved immersion. Scholars have explored feelies as paratexts, while video game journalists have recalled them fondly.