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🔗 Exception That Proves the Rule
"The exception that proves the rule" (sometimes "the exception proves the rule") is a saying whose meaning is contested. Henry Watson Fowler's Modern English Usage identifies five ways in which the phrase has been used, and each use makes some sort of reference to the role that a particular case or event takes in relation to a more general rule.
Two original meanings of the phrase are usually cited. The first, preferred by Fowler, is that the presence of an exception applying to a specific case establishes ("proves") that a general rule exists. A more explicit phrasing might be "the exception that proves the existence of the rule." Most contemporary uses of the phrase emerge from this origin, although often in a way which is closer to the idea that all rules have their exceptions. The alternative origin given is that the word "prove" is used in the archaic sense of "test". In this sense, the phrase does not mean that an exception demonstrates a rule to be true or to exist, but that it tests the rule, thereby proving its value. There is little evidence of the phrase being used in this second way.
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- "Exception That Proves the Rule" | 2019-05-05 | 10 Upvotes 2 Comments
🔗 Goro Shimura has died
Gorō Shimura (志村 五郎, Shimura Gorō, 23 February 1930 – 3 May 2019) was a Japanese mathematician and Michael Henry Strater Professor Emeritus of Mathematics at Princeton University who worked in number theory, automorphic forms, and arithmetic geometry. He was known for developing the theory of complex multiplication of abelian varieties and Shimura varieties, as well as posing the Taniyama–Shimura conjecture which ultimately led to the proof of Fermat's Last Theorem.
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- "Goro Shimura has died" | 2019-05-04 | 86 Upvotes 10 Comments
🔗 Emirp Primes
An emirp (prime spelled backwards) is a prime number that results in a different prime when its decimal digits are reversed. This definition excludes the related palindromic primes. The term reversible prime is used to mean the same as emirp, but may also, ambiguously, include the palindromic primes.
The sequence of emirps begins 13, 17, 31, 37, 71, 73, 79, 97, 107, 113, 149, 157, 167, 179, 199, 311, 337, 347, 359, 389, 701, 709, 733, 739, 743, 751, 761, 769, 907, 937, 941, 953, 967, 971, 983, 991, ... (sequence A006567 in the OEIS).
All non-palindromic permutable primes are emirps.
As of November 2009, the largest known emirp is 1010006+941992101×104999+1, found by Jens Kruse Andersen in October 2007.
The term 'emirpimes' (singular) is used also in places to treat semiprimes in a similar way. That is, an emirpimes is a semiprime that is also a (distinct) semiprime upon reversing its digits.
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- "Emirp Primes" | 2019-05-02 | 27 Upvotes 14 Comments
🔗 Gutter Oil
Gutter oil (Chinese: 地沟油; pinyin: dìgōu yóu, or 餿水油; sōushuǐ yóu) is oil which has been recycled from waste oil collected from sources such as restaurant fryers, grease traps, slaughterhouse waste and fatbergs.
Reprocessing of used cooking oil is often very rudimentary; techniques include filtration, boiling, refining, and the removal of some adulterants. It is then packaged and resold as a cheaper alternative to normal cooking oil. Another version of gutter oil uses discarded animal parts, animal fat and skins, internal organs, and expired or otherwise low-quality meat, which is then cooked in large vats in order to extract the oil. Used kitchen oil can be purchased for between $859 and $937 per ton, while the cleaned and refined product can sell for $1,560 per ton. Thus there is great economic incentive to produce and sell gutter oil.
It was estimated in 2011 that up to one in every ten lower-market restaurant meals consumed in China is prepared with recycled oil. As Feng Ping of the China Meat Research Center has said: "The illegal oil shows no difference in appearance and indicators after refining and purification because the law breakers are skillful at coping with the established standards."
Some street vendors and restaurants in China and Taiwan have illegally used recycled oil unfit for human consumption for the purposes of cooking food, leading to a crackdown against such establishments by the Chinese and Taiwanese governments.
Gutter oil is an acceptable raw ingredient for products that are not for human consumption, such as soap, rubber, bio-fuel, and cosmetics.
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- "Gutter Oil" | 2019-05-01 | 11 Upvotes 3 Comments
🔗 Apollo 15 postage stamp incident
The Apollo 15 postal covers incident, a 1972 NASA scandal, involved the astronauts of Apollo 15, who carried about 400 unauthorized postal covers into space and to the Moon's surface on the Lunar Module Falcon. Some of the envelopes were sold at high prices by West German stamp dealer Hermann Sieger, and are known as "Sieger covers". The crew of Apollo 15, David Scott, Alfred Worden and James Irwin, agreed to take payments for carrying the covers; though they returned the money, they were reprimanded by NASA. Amid much press coverage of the incident, the astronauts were called before a closed session of a Senate committee and never flew in space again.
The three astronauts and an acquaintance, Horst Eiermann, had agreed to have the covers made and taken into space. Each astronaut was to receive about $7,000. Scott arranged to have the covers postmarked on the morning of the Apollo 15 launch on July 26, 1971. They were packaged for space and brought to him as he prepared for liftoff. Due to an error, they were not included on the list of the personal items he was taking into space. The covers spent July 30 to August 2 on the Moon inside Falcon. On August 7, the date of splashdown, the covers were postmarked again on the recovery carrier USS Okinawa. One hundred were sent to Eiermann (and passed on to Sieger); the remaining covers were divided among the astronauts.
Worden had agreed to carry 144 additional covers, largely for an acquaintance, F. Herrick Herrick; these had been approved for travel to space. Apollo 15 carried a total of approximately 641 covers. In late 1971, when NASA learned that the Herrick covers were being sold, the astronauts' supervisor, Deke Slayton, warned Worden to avoid further commercialization of what he had been allowed to take into space. After Slayton heard of the Sieger arrangement, he removed the three as backup crew members for Apollo 17, though the astronauts had by then refused compensation from Sieger and Eiermann. The Sieger matter became generally known in the newspapers in June 1972. There was widespread coverage; some said astronauts should not be allowed to reap personal profits from NASA missions.
By 1977, all three former astronauts had left NASA. In 1983, Worden sued, and the covers were returned to them. One of the postal covers given to Sieger sold for over $50,000 in 2014.
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- "Apollo 15 postage stamp incident" | 2019-04-30 | 133 Upvotes 49 Comments
🔗 Tokyo's Underground Discharge Channel
The Metropolitan Area Outer Underground Discharge Channel (Japanese: 首都圏外郭放水路, Hepburn: shutoken gaikaku hōsuiro), is an underground water infrastructure project in Kasukabe, Saitama, Japan. It is the world's largest underground flood water diversion facility, built to mitigate overflowing of the city's major waterways and rivers during rain and typhoon seasons. It is located between Showa in Tokyo and Kasukabe in Saitama prefecture, on the outskirts of the city of Tokyo in the Greater Tokyo Area, Japan.
Work on the project started in 1992 and was completed by early 2006. It consists of five concrete containment silos with heights of 65 m and diameters of 32 m, connected by 6.4 km of tunnels, 50 m beneath the surface, as well as a large water tank with a height of 25.4 m, with a length of 177m, with a width of 78m, and with 59 massive pillars connected to 78 10 MW (13,000 hp) pumps that can pump up to 200 tons of water into the Edo River per second.
"Ryukyukan" for Underground Exploration Museum of The Metropolitan Area Outer Underground Discharge Channel is also a tourist attraction and can be visited for 3.000 Yen; however, as the tours are conducted in Japanese, a Japanese speaker must be present in the group to act as a translator for non-Japanese speakers.
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- "Tokyo's Underground Discharge Channel" | 2019-04-30 | 96 Upvotes 40 Comments
🔗 The Seven Dangerous Western Values (2013)
Document Number Nine (or Document No. 9), more properly the Communiqué on the Current State of the Ideological Sphere (also translated as the Briefing on the Current Situation in the Ideological Realm), is a confidential internal document widely circulated within the Communist Party of China in 2013 by the General Office of the Communist Party of China. The document was first circulated in July 2012. The document warns of seven dangerous Western values, allegedly including media freedom and judicial independence. Teaching on any of the seven topics is forbidden. There is an emphasis on controlling and preventing communication using the internet of ideas subversive to one party rule. The document was issued in the context of planned economic reforms and increased calls for political reform. It has been described as a critique of the "liberal ways of thinking".
The document was not made available to public by the Communist Party or any branches of the Chinese government, but in July 2013 was allegedly leaked by Chinese dissident journalist Gao Yu, who was in turn sentenced to a seven-year imprisonment for "leaking state secrets".
It is unclear whether this document is official Chinese policy or just a faction within the party. However, The New York Times suggests that it "bears the unmistakable imprimatur of Xi Jinping". It is thought that Document No. 9 was issued by the Central Committee General Office, and would have required the approval of Mr. Xi and other top leaders. A severe crackdown against human rights lawyers, media outlets, academics, and other such independent thinkers has followed the document's publication.
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- "The Seven Dangerous Western Values (2013)" | 2019-04-29 | 38 Upvotes 5 Comments
🔗 Nanoscale Vacuum-Channel Transistor
A nanoscale vacuum-channel transistor (NVCT) is a theoretically visioned transistor in which the electron transport medium is a vacuum. In a traditional solid-state transistor, a semiconductor channel exists between the source and the drain, and the current flows through the semiconductor. However, in a nanoscale vacuum-channel transistor, no material exists between the source and the drain, and therefore, the current flows through the vacuum. However, experimental realization of such a transistor has not been demonstrated.
Theoretically, a vacuum-channel transistor is expected to operate faster than a traditional solid-state transistor, and have higher power output. Moreover, vacuum-channel transistors are expected to operate at higher temperature and radiation level than a traditional transistor making them suitable for space application.
The development of vacuum-channel transistors is still at a very early research stage, and there are only limited study in recent literature such as vertical field-emitter vacuum-channel transistor, gate-insulated planar electrodes vacuum-channel transistor, vertical vacuum-channel transistor, and all-around gate vacuum-channel transistor.
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- "Nanoscale Vacuum-Channel Transistor" | 2019-04-29 | 20 Upvotes 8 Comments
🔗 Eirôn
In the theatre of ancient Greece, the eirôn (Ancient Greek: εἴρων) was one of three stock characters in comedy. The eirôn usually succeeded in bringing down his braggart opponent (the alazôn) by understating his own abilities.
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- "Eirôn" | 2019-04-28 | 11 Upvotes 1 Comments
🔗 The Baghdad Battery
The Baghdad Battery or Parthian Battery is a set of three artifacts which were found together: a ceramic pot, a tube of copper, and a rod of iron. It was discovered in modern Khujut Rabu, Iraq, close to the metropolis of Ctesiphon, the capital of the Parthian (150 BC – 223 AD) and Sasanian (224–650 AD) empires of Persia, and it is considered to date from either of these periods.
Its origin and purpose remain unclear. It was hypothesized by some researchers that the object functioned as a galvanic cell, possibly used for electroplating, or some kind of electrotherapy, but there is no electroplated object known from this period. An alternative explanation is that it functioned as a storage vessel for sacred scrolls.
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- "The Baghdad Battery" | 2019-04-28 | 76 Upvotes 19 Comments