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🔗 Biography 🔗 Biography/science and academia 🔗 Astronomy 🔗 Middle Ages 🔗 Middle Ages/History

Ala al-Dīn Ali ibn Muhammed (1403 – 16 December 1474), known as Ali Qushji (Ottoman Turkish/Persian language: علی قوشچی, kuşçu – falconer in Turkish; Latin: Ali Kushgii) was an astronomer, mathematician and physicist originally from Samarkand, who settled in the Ottoman Empire some time before 1472. As a disciple of Ulugh Beg, he is best known for the development of astronomical physics independent from natural philosophy, and for providing empirical evidence for the Earth's rotation in his treatise, Concerning the Supposed Dependence of Astronomy upon Philosophy. In addition to his contributions to Ulugh Beg's famous work Zij-i-Sultani and to the founding of Sahn-ı Seman Medrese, one of the first centers for the study of various traditional Islamic sciences in the Ottoman caliphate, Ali Kuşçu was also the author of several scientific works and textbooks on astronomy.

🔗 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).

🔗 Psychology

Reactance is an unpleasant motivational arousal (reaction) to offers, persons, rules, or regulations that threaten or eliminate specific behavioral freedoms. Reactance occurs when a person feels that someone or something is taking away their choices or limiting the range of alternatives.

Reactance can occur when someone is heavily pressured to accept a certain view or attitude. Reactance can cause the person to adopt or strengthen a view or attitude that is contrary to what was intended, and also increases resistance to persuasion. People using reverse psychology are playing on reactance, attempting to influence someone to choose the opposite of what they request.

Some individuals are naturally high in reactance, a personality characteristic called trait reactance.

"Pierre Menard, Author of the Quixote" (original Spanish title: "Pierre Menard, autor del Quijote") is a short story by Argentine writer Jorge Luis Borges.

It originally appeared in Spanish in the Argentine journal Sur in May 1939. The Spanish-language original was first published in book form in Borges's 1941 collection El jardín de senderos que se bifurcan (The Garden of Forking Paths), which was included in his much-reprinted Ficciones (1944).

🔗 Technology 🔗 Physics 🔗 Physics/Fluid Dynamics

Fluidics, or fluidic logic, is the use of a fluid to perform analog or digital operations similar to those performed with electronics.

The physical basis of fluidics is pneumatics and hydraulics, based on the theoretical foundation of fluid dynamics. The term fluidics is normally used when devices have no moving parts, so ordinary hydraulic components such as hydraulic cylinders and spool valves are not considered or referred to as fluidic devices.

A jet of fluid can be deflected by a weaker jet striking it at the side. This provides nonlinear amplification, similar to the transistor used in electronic digital logic. It is used mostly in environments where electronic digital logic would be unreliable, as in systems exposed to high levels of electromagnetic interference or ionizing radiation.

Nanotechnology considers fluidics as one of its instruments. In this domain, effects such as fluid-solid and fluid-fluid interface forces are often highly significant. Fluidics have also been used for military applications.

🔗 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.

🔗 Mathematics

Sexy primes are prime numbers that differ from each other by 6. For example, the numbers 5 and 11 are both sexy primes, because 11 - 5 = 6.

The term "sexy prime" is a pun stemming from the Latin word for six: sex.

If p + 2 or p + 4 (where p is the lower prime) is also prime, then the sexy prime is part of a prime triplet.

A milk watcher, milk saver, pot watcher, pot minder, milk guard, or boil over preventer is a cooking utensil placed at the bottom of a pot to prevent the foaming boil-over of liquids by collecting small bubbles of steam into one large bubble.

🔗 China/Chinese history 🔗 China

The south-pointing chariot (or carriage) was an ancient Chinese two-wheeled vehicle that carried a movable pointer to indicate the south, no matter how the chariot turned. Usually, the pointer took the form of a doll or figure with an outstretched arm. The chariot was supposedly used as a compass for navigation and may also have had other purposes.

The ancient Chinese invented a mobile-like armored cart in the 5th century BC called the Dongwu Che (Chinese: 洞屋车). It was used for the purpose of protecting warriors on the battlefield. The Chinese war wagon was designed as a kind of mobile protective cart with a shed-like roof. It would serve to be rolled up to city fortifications to provide protection for sappers digging underneath to weaken a wall's foundation. The early Chinese war wagon became the basis of technologies for the making of ancient Chinese south-pointing chariots.

There are legends of earlier south-pointing chariots, but the first reliably documented one was created by the Chinese mechanical engineer Ma Jun (c. 200–265 CE) of Cao Wei during the Three Kingdoms. No ancient chariots still exist, but many extant ancient Chinese texts mention them, saying they were used intermittently until about 1300 CE. Some include information about their inner components and workings.

There were probably several types of south-pointing chariot which worked differently. In most or all of them, the rotating road wheels mechanically operated a geared mechanism to keep the pointer aimed correctly. The mechanism had no magnets and did not automatically detect which direction was south. The pointer was aimed southward by hand at the start of a journey. Subsequently, whenever the chariot turned, the mechanism rotated the pointer relative to the body of the chariot to counteract the turn and keep the pointer aiming in a constant direction, to the south. Thus the mechanism did a kind of directional dead reckoning, which is inherently prone to cumulative errors and uncertainties. Some chariots' mechanisms may have had differential gears, technology unseen since the ancient Greek Antikythera mechanism.

🔗 Pharmacology 🔗 Dentistry

A caries vaccine is a vaccine to prevent and protect against tooth decay. Streptococcus mutans (S. mutans) has been identified as the major etiological agent of human dental caries. The development of a vaccine for tooth decay has been under investigation since the 1970s. In 1972, a caries vaccine was said to be in animal testing in England, and that it would have begun human testing soon. However, intrinsic difficulties in developing it, coupled with lack of strong economic interests, are the reasons why still no such vaccine is commercially available today. Several types of vaccines are being developed at research centres, with some kind of caries vaccines being considered to diminish or prevent dental caries' impact on young people.