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🔗 Aviation 🔗 France 🔗 Germany 🔗 Disaster management 🔗 Aviation/Aviation accident 🔗 Spain 🔗 Crime and Criminal Biography

Germanwings Flight 9525 was a scheduled international passenger flight from Barcelona–El Prat Airport in Spain to Düsseldorf Airport in Germany. The flight was operated by Germanwings, a low-cost carrier owned by the German airline Lufthansa. On 24 March 2015, the aircraft, an Airbus A320-211, crashed 100 km (62 mi; 54 nmi) north-west of Nice in the French Alps. All 144 passengers and six crew members were killed.

The crash was deliberately caused by the co-pilot, Andreas Lubitz, who had previously been treated for suicidal tendencies and declared unfit to work by his doctor. Lubitz kept this information from his employer and instead reported for duty. Shortly after reaching cruise altitude and while the captain was out of the cockpit, Lubitz locked the cockpit door and initiated a controlled descent that continued until the aircraft hit a mountainside.

Aviation authorities swiftly implemented new recommendations from the European Union Aviation Safety Agency that required two authorised personnel in the cockpit at all times but, by 2017, Germanwings and other German airlines had dropped the rule.

The Lubitz family held a press conference in March 2017 during which Lubitz's father said that they did not accept the official investigative findings that his son deliberately caused the crash. By 2017, Lufthansa had paid €75,000 to the family of every victim, as well as €10,000 in pain and suffering compensation to every close relative of a victim.

🔗 International relations 🔗 Military history 🔗 British Empire 🔗 Military history/Cold War 🔗 Military history/European military history 🔗 Military history/British military history 🔗 Commonwealth

Operation Legacy was a British Colonial Office (later Foreign Office) programme to destroy or hide files, to prevent them being inherited by its ex-colonies. It ran from the 1950s until the 1970s, when the decolonisation of the British Empire was at its height.

MI5 or Special Branch agents vetted all secret documents in the colonial administrations to find those that those that could embarrass the British government—for instance by showing racial or religious bias. They identified 8,800 files to conceal from at least 23 countries and territories in the 1950s and 1960s, and destroyed them or sent them to the United Kingdom. Precise instructions were given for methods to be used for destruction, including burning and dumping at sea. Some of the files detailed torture methods used against opponents of the colonial administrations, such as during the Mau Mau Uprising.

As decolonisation progressed, British officials were keen to avoid a repeat of the embarrassment that had been caused by the overt burning of documents that took place in New Delhi in 1947, which had been covered by Indian news sources. On 3 May 1961, Iain Macleod, who was Secretary of State for the Colonies, wrote a telegram to all British embassies to advise them on the best way to retrieve and dispose of sensitive documents. To prevent post-colonial governments from ever learning about Operation Legacy, officials were required to dispatch "destruction certificates" to London. In some cases, as the handover date approached, the immolation task proved so huge that colonial administrators warned the Foreign Office that there was a danger of "celebrating Independence Day with smoke."

Academic study of the end of the British Empire has been assisted in recent years by the declassification of the migrated archives in the Foreign and Commonwealth Office (FCO) 141 series. After the UK government admitted in 2011 that it had secret documents related to the Mau Mau Uprising, it began to declassify documents and by November 2013 some 20,000 files had been declassified. These documents can now be accessed at the National Archives in Kew, London.

🔗 Business 🔗 Psychology

Theory X and Theory Y are theories of human work motivation and management. They were created by Douglas McGregor while he was working at the MIT Sloan School of Management in the 1950s, and developed further in the 1960s. McGregor's work was rooted in motivation theory alongside the works of Abraham Maslow, who created the hierarchy of needs. The two theories proposed by McGregor describe contrasting models of workforce motivation applied by managers in human resource management, organizational behavior, organizational communication and organizational development. Theory X explains the importance of heightened supervision, external rewards, and penalties, while Theory Y highlights the motivating role of job satisfaction and encourages workers to approach tasks without direct supervision. Management use of Theory X and Theory Y can affect employee motivation and productivity in different ways, and managers may choose to implement strategies from both theories into their practices.

🔗 Mathematics

In mathematical logic, Goodstein's theorem is a statement about the natural numbers, proved by Reuben Goodstein in 1944, which states that every Goodstein sequence eventually terminates at 0. Laurence Kirby and Jeff Paris showed that it is unprovable in Peano arithmetic (but it can be proven in stronger systems, such as second-order arithmetic). This was the third example of a true statement about natural numbers that is unprovable in Peano arithmetic, after the examples provided by Gödel's incompleteness theorem and Gerhard Gentzen's 1943 direct proof of the unprovability of ε₀-induction in Peano arithmetic. The Paris–Harrington theorem gave another example.

Kirby and Paris introduced a graph-theoretic hydra game with behavior similar to that of Goodstein sequences: the "Hydra" (named for the mythological multi-headed Hydra of Lerna) is a rooted tree, and a move consists of cutting off one of its "heads" (a branch of the tree), to which the hydra responds by growing a finite number of new heads according to certain rules. Kirby and Paris proved that the Hydra will eventually be killed, regardless of the strategy that Hercules uses to chop off its heads, though this may take a very long time. Just like for Goodstein sequences, Kirby and Paris showed that it cannot be proven in Peano arithmetic alone.

🔗 Computing 🔗 Computing/Computer hardware 🔗 Computing/Early computers

In computer jargon, blinkenlights are diagnostic lights on front panels of old mainframe computers. More recently the term applies to status lights of modern network hardware (modems, network hubs, etc.). Blinkenlights disappeared from more recent computers for a number of reasons, the most important being the fact that with faster CPUs a human can no longer interpret the processes in the computer on the fly. Though more sophisticated UI mechanisms have since been developed, blinkenlights may still be present as additional status indicators and familiar skeuomorphs.

🔗 Technology 🔗 Telecommunications

The telautograph, an analog precursor to the modern fax machine, transmits electrical impulses recorded by potentiometers at the sending station to servomechanisms attached to a pen at the receiving station, thus reproducing at the receiving station a drawing or signature made by the sender. It was the first such device to transmit drawings to a stationary sheet of paper; previous inventions in Europe had used rotating drums to make such transmissions.

The telautograph's invention is attributed to Elisha Gray, who patented it on July 31, 1888. Gray's patent stated that the telautograph would allow "one to transmit his own handwriting to a distant point over a two-wire circuit." It was the first facsimile machine in which the stylus was controlled by horizontal and vertical bars. The telautograph was first publicly exhibited at the 1893 World's Columbian Exposition held in Chicago.

While the patent schema's geometry implies vertical and horizontal coordinates, systems used in the 20th Century (and presumably before) had a different coordinate scheme, based on transmitting two angles.

In an 1888 interview in The Manufacturer & Builder (Vol. 24: No. 4: pages 85–86) Gray made this statement:

By my invention you can sit down in your office in Chicago, take a pencil in your hand, write a message to me, and as your pencil moves, a pencil here in my laboratory moves simultaneously, and forms the same letters and words in the same way. What you write in Chicago is instantly reproduced here in fac-simile. You may write in any language, use a code or cipher, no matter, a fac-simile is produced here. If you want to draw a picture it is the same, the picture is reproduced here. The artist of your newspaper can, by this device, telegraph his pictures of a railway wreck or other occurrences just as a reporter telegraphs his description in words.

By the end of the 19th century, the telautograph was modified by Foster Ritchie. Calling it the telewriter, Ritchie's version of the telautograph could be operated using a telephone line for simultaneous copying and speaking.

The telautograph became very popular for the transmission of signatures over a distance, and in banks and large hospitals to ensure that doctors' orders and patient information were transmitted quickly and accurately. Teleautograph systems were installed in a number of major railroad stations to relay hand-written reports of train movements from the interlocking tower to various parts of the station. The teleautograph network in Grand Central Terminal included a public display in the main concourse into the 1960s; a similar setup in Chicago Union Station remained in operation into the 1970s.

A Telautograph was used in 1911 to warn workers on the 10th floor about the Triangle Shirtwaist Factory fire that had broken out two floors below. An example of a Telautograph machine writing script can be seen in the 1956 movie Earth vs the Flying Saucers as the output device for the mechanical translator.

Telautograph Corporation changed its name several times. In 1971, it was acquired by Arden/Mayfair. In 1993, Danka Industries purchased the company and renamed it Danka/Omnifax. In 1999, Xerox corporation purchased the company and called it the Omnifax division, which has since been absorbed by the corporation.

🔗 Philately

Rocket mail is the delivery of mail by rocket or missile. The rocket lands by deploying an internal parachute upon arrival. It has been attempted by various organizations in many different countries, with varying levels of success. It has never become widely seen as being a viable option for delivering mail, due to the cost of the schemes and numerous failures.

The collection of philatelic material ("stamps") used for (and depicting) rocket mail is part of a specialist branch of aerophilately known as astrophilately.

🔗 Philosophy 🔗 Philosophy/Logic 🔗 Philosophy/Epistemology

The unexpected hanging paradox or hangman paradox is a paradox about a person's expectations about the timing of a future event which they are told will occur at an unexpected time. The paradox is variously applied to a prisoner's hanging, or a surprise school test. It could be reduced to be Moore's paradox.

Despite significant academic interest, there is no consensus on its precise nature and consequently a final correct resolution has not yet been established. Logical analysis suggests that the problem arises in a self-contradictory self-referencing statement at the heart of the judge's sentence. Epistemological studies of the paradox have suggested that it turns on our concept of knowledge. Even though it is apparently simple, the paradox's underlying complexities have even led to its being called a "significant problem" for philosophy.

🔗 Russia 🔗 Mathematics 🔗 Statistics 🔗 Russia/science and education in Russia

In statistics, the Gauss–Markov theorem states that the ordinary least squares (OLS) estimator has the lowest sampling variance within the class of linear unbiased estimators, if the errors in the linear regression model are uncorrelated, have equal variances and expectation value of zero. The errors do not need to be normal, nor do they need to be independent and identically distributed (only uncorrelated with mean zero and homoscedastic with finite variance). The requirement that the estimator be unbiased cannot be dropped, since biased estimators exist with lower variance. See, for example, the James–Stein estimator (which also drops linearity) or ridge regression.

The theorem was named after Carl Friedrich Gauss and Andrey Markov, although Gauss' work significantly predates Markov's. But while Gauss derived the result under the assumption of independence and normality, Markov reduced the assumptions to the form stated above. A further generalization to non-spherical errors was given by Alexander Aitken.

🔗 Science

Operation Serenata de Amor is an artificial intelligence project to analyze public spending in Brazil. The project has been funded by a recurrent financing campaign since September 7, 2016, and came in the wake of major scandals of misappropriation of public funds in Brazil, such as the Mensalão scandal and what was revealed in the Operation Car Wash investigations.

The analysis began with data from the National Congress and then expanded to other types of budget and other instances of government, such as the Federal Senate. The project is built through collaboration on GitHub and using a public group with more than 600 participants on Telegram.

The name "Serenata de Amor," which means "serenade of love," was taken from a popular cashew cream bonbon produced by Chocolates Garoto in Brazil.