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🔗 Mathematics

In number theory, specifically the study of Diophantine approximation, the lonely runner conjecture is a conjecture about the long-term behavior of runners on a circular track. It states that ${\displaystyle n}$ runners on a track of unit length, with constant speeds all distinct from one another, will each be lonely at some time—at least ${\displaystyle 1/n}$ units away from all others.

The conjecture was first posed in 1967 by German mathematician Jörg M. Wills, in purely number-theoretic terms, and independently in 1974 by T. W. Cusick; its illustrative and now-popular formulation dates to 1998. The conjecture is known to be true for 7 runners or less, but the general case remains unsolved. Implications of the conjecture include solutions to view-obstruction problems and bounds on properties, related to chromatic numbers, of certain graphs.

🔗 Spaceflight 🔗 Moon

The Apollo 11 missing tapes were those that were recorded from Apollo 11's slow-scan television (SSTV) telecast in its raw format on telemetry data tape at the time of the first Moon landing in 1969 and subsequently lost. The data tapes were recorded as a backup in case the live television broadcasts failed for any reason.

To broadcast the SSTV transmission on standard television, NASA ground receiving stations performed real-time scan conversion to the NTSC television format. The moonwalk's converted video signal was broadcast live around the world on July 21, 1969 (2:56 UTC). At the time, the NTSC broadcast was recorded on many videotapes and kinescope films. Many of these low-quality recordings remain intact. As the real-time broadcast worked and was widely recorded, preservation of the backup video was not deemed a priority in the years immediately following the mission. In the early 1980s, NASA's Landsat program was facing a severe data tape shortage and it is likely the tapes were erased and reused at this time.

A team of retired NASA employees and contractors tried to find the tapes in the early 2000s but was unable to do so. The search was sparked when several still photographs appeared in the late 1990s that showed the visually superior raw SSTV transmission on ground-station monitors. The research team conducted a multi-year investigation in the hopes of finding the most pristine and detailed video images of the moonwalk. If copies of the original SSTV format tapes were to be found, more modern digital technology could make a higher-quality conversion, yielding better images than those originally seen. The researchers concluded that the tapes containing the raw unprocessed Apollo 11 SSTV signal were erased and reused by NASA in the early 1980s, following standard procedure at the time.

Although the researchers never found the telemetry tapes, they did discover the best visual quality NTSC videotapes as well as Super 8 movie film taken of a video monitor in Australia, showing the SSTV transmission before it was converted. These visual elements were processed in 2009, as part of a NASA-approved restoration project of the first moonwalk. At a 2009 news conference in Washington, D.C., the research team released its findings regarding the tapes' disappearance. They also partially released newly enhanced footage obtained during the search. Lowry Digital completed the full moonwalk restoration project in late 2009.

🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation 🔗 Aviation/Aviation accident 🔗 Wiltshire 🔗 Military history/European military history 🔗 Military history/British military history

On 22 July 1966 Walter "Taffy" Holden, an engineer in command of No. 33 Maintenance Unit RAF with limited experience flying small single-engine trainer aircraft, inadvertently engaged the afterburner of a Mach 2.0-capable English Electric Lightning during ground testing. Unable to disengage the afterburner, Holden ran down the runway, narrowly missing a crossing fuel bowser and a de Havilland Comet taking off, before taking off himself. Flying without a helmet or canopy, the ejection seat disabled, and the landing gear locked down, Holden aborted his first two landing attempts. He landed on his third approach, striking the runway with the aircraft's tail as he adopted in his flare the attitude of a taildragger aircraft. The aircraft returned to service, and was subsequently acquired by the Imperial War Museum Duxford.

🔗 United States 🔗 International relations 🔗 Soviet Union 🔗 Agriculture 🔗 Trade 🔗 Soviet Union/economy of Russia

The great grain robbery was the July 1972 purchase of 10 million tons of grain (mainly wheat and corn) from the United States by the Soviet Union at subsidized prices, which caused global grain prices to soar. Crop shortfalls in 1971 and 1972 forced the Soviet Union to look abroad for grain, hoping to prevent famine or crisis. Soviet negotiators worked out a deal to buy grain on credit, but quickly exceeded their credit limit. The American negotiators did not realize that both the Soviets and the world grain market had suffered shortfalls, and thus chose to subsidize the purchase. The strategy backfired and intensified the crisis with global food prices rose at least 30%, and grain stockpiles were decimated.

🔗 Human rights 🔗 Canada 🔗 LGBT studies 🔗 Law Enforcement 🔗 Discrimination

"Fruit machine" is a term for a device developed in Canada by Frank Robert Wake that was supposed to be able to identify gay men (derogatorily referred to as "fruits"). The subjects were made to view pornography; the device then measured the diameter of the pupils of the eyes (pupillary response test), perspiration, and pulse for a supposed erotic response.

The "fruit machine" was employed in Canada in the 1950s and 1960s during a campaign to eliminate all gay men from the civil service, the Royal Canadian Mounted Police (RCMP), and the military. A substantial number of workers did lose their jobs. Although funding for the "fruit machine" project was cut off in the late 1960s, the investigations continued, and the RCMP collected files on over 9,000 "suspected" gay people.

The chair employed resembled that used by dentists. It had a pulley with a camera going towards the pupils, with a black box located in front of it that displayed pictures. The pictures ranged from the mundane to sexually explicit photos of men and women. It had previously been determined that the pupils would dilate in relation to the amount of interest in the picture per the technique termed 'the pupillary response test'.

People were first led to believe that the machine's purpose was to rate stress. After knowledge of its real purpose became widespread, few people volunteered for it.

🔗 Computing 🔗 Robotics

The Viterbi algorithm is a dynamic programming algorithm for obtaining the maximum a posteriori probability estimate of the most likely sequence of hidden states—called the Viterbi path—that results in a sequence of observed events, especially in the context of Markov information sources and hidden Markov models (HMM).

The algorithm has found universal application in decoding the convolutional codes used in both CDMA and GSM digital cellular, dial-up modems, satellite, deep-space communications, and 802.11 wireless LANs. It is now also commonly used in speech recognition, speech synthesis, diarization, keyword spotting, computational linguistics, and bioinformatics. For example, in speech-to-text (speech recognition), the acoustic signal is treated as the observed sequence of events, and a string of text is considered to be the "hidden cause" of the acoustic signal. The Viterbi algorithm finds the most likely string of text given the acoustic signal.

🔗 British Museum 🔗 Radio 🔗 BBC 🔗 Radio/UK Radio

A History of the World in 100 Objects was a joint project of BBC Radio 4 and the British Museum, comprising a 100-part radio series written and presented by British Museum director Neil MacGregor. In 15-minute presentations broadcast on weekdays on Radio 4, MacGregor used objects of ancient art, industry, technology and arms, all of which are in the British Museum's collections, as an introduction to parts of human history. The series, four years in planning, began on 18 January 2010 and was broadcast over 20 weeks. A book to accompany the series, A History of the World in 100 Objects by Neil MacGregor, was published by Allen Lane on 28 October 2010. The entire series is also available for download along with an audio version of the book for purchase. The British Museum won the 2011 Art Fund Prize for its role in hosting the project.

In 2016, a touring exhibition of several items depicted on the radio program, also titled A History of the World in 100 Objects, travelled to various destinations, including Abu Dhabi (Manarat Al Saadiyat), Taiwan (National Palace Museum in Taipei), Japan (Tokyo Metropolitan Art Museum in Tokyo, Kyushu National Museum in Daizafu, and Kobe City Museum in Kobe), Australia (Western Australian Museum in Perth and National Museum of Australia in Canberra), and China (National Museum of China in Beijing and Shanghai Museum in Shanghai).

🔗 Japan 🔗 Japan/Culture 🔗 Textile Arts

Shibori (しぼり / 絞り) is a Japanese manual resist dyeing technique, which produces a number of different patterns on fabric.

Alternative Title: Just because you have some money, that doesn't mean that you have to spend it.

In biology, the hallmarks of an aggressive cancer include limitless multiplication of ordinarily beneficial cells, even when the body signals that further multiplication is no longer needed. The Wikipedia page on the wheat and chessboard problem explains that nothing can keep growing forever. In biology, the unwanted growth usually terminates with the death of the host. Ever-increasing spending can often lead to the same undesirable result in organizations.

🔗 Russia 🔗 Russia/demographics and ethnography of Russia 🔗 Russia/history of Russia

The Russian Cross is the name of a demographic trend that occurred in Russia and many other countries of the former Warsaw Pact. In Russia, starting in 1988, birth rates among native Russians (as well as most other ethnic groups of the European part of the former Soviet Union) were declining, while from 1991 the death rates started climbing.

In 1992, the number of deaths exceeded the number of births, and continued to do so to a greater or lesser degree until 2013. When this trend is plotted on a line graph starting from the mid-1980s, the lines cross at 1992, hence the name.