Random Articles (Page 3)
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๐ Shigir Idol
The Shigir Sculpture, or Shigir Idol (Russian: ะจะธะณะธััะบะธะน ะธะดะพะป), is the oldest known wooden sculpture in the world, made during the Mesolithic period, shortly after the end of the last Ice Age. The wood it was carved from is approximately 11,500 years old. It is displayed in the Sverdlovsk Regional Museum of Local Lore in Yekaterinburg, Russia.
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- "Shigir Idol" | 2019-09-15 | 45 Upvotes 14 Comments
๐ KochenโSpecker theorem
In quantum mechanics, the KochenโSpecker (KS) theorem, also known as the BellโKochenโSpecker theorem, is a "no-go" theorem proved by John S. Bell in 1966 and by Simon B. Kochen and Ernst Specker in 1967. It places certain constraints on the permissible types of hidden-variable theories, which try to explain the predictions of quantum mechanics in a context-independent way. The version of the theorem proved by Kochen and Specker also gave an explicit example for this constraint in terms of a finite number of state vectors.
The theorem is a complement to Bell's theorem (to be distinguished from the (Bellโ)KochenโSpecker theorem of this article). While Bell's theorem established nonlocality to be a feature of any hidden variable theory that recovers the predictions of quantum mechanics, the KS theorem established contextuality to be an inevitable feature of such theories.
The theorem proves that there is a contradiction between two basic assumptions of the hidden-variable theories intended to reproduce the results of quantum mechanics: that all hidden variables corresponding to quantum-mechanical observables have definite values at any given time, and that the values of those variables are intrinsic and independent of the device used to measure them. The contradiction is caused by the fact that quantum-mechanical observables need not be commutative. It turns out to be impossible to simultaneously embed all the commuting subalgebras of the algebra of these observables in one commutative algebra, assumed to represent the classical structure of the hidden-variables theory, if the Hilbert space dimension is at least three.
The KochenโSpecker theorem excludes hidden-variable theories that assume that elements of physical reality can all be consistently represented simultaneously by the quantum mechanical Hilbert space formalism disregarding the context of a particular framework (technically a projective decomposition of the identity operator) related to the experiment or analytical viewpoint under consideration. As succinctly worded by Isham and Butterfield, (under the assumption of a universal probabilistic sample space as in non-contextual hidden variable theories) the KochenโSpecker theorem "asserts the impossibility of assigning values to all physical quantities whilst, at the same time, preserving the functional relations between them".
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- "KochenโSpecker theorem" | 2016-07-23 | 24 Upvotes 1 Comments
๐ Oi (Interjection)
Oi is an interjection used in various varieties of the English language, particularly Australian English, British English, Indian English, Irish English, New Zealand English, and South African English, as well as non-English languages such as Chinese, Tagalog, Tamil, Hindi/Urdu, Japanese, and Portuguese to get the attention of another person or to express surprise or disapproval. It is sometimes used in Canadian English and very rarely in American English. The word is also common in the Indian subcontinent, where it has varied pronunciations of "O-ee" and "O-ye".
"Oi" has been particularly associated with working class and Cockney speech. It is effectively a local pronunciation of "hoy" (see H-dropping), an older expression. A study of the Cockney dialect in the 1950s found that whether it was being used to call attention or as a challenge depended on its tone and abruptness. The study's author noted that the expression is "jaunty and self-assertive" as well as "intensely cockney".
A poll of non-English speakers by the British Council in 2004 found that "oi" was considered the 61st most beautiful word in the English language. A spokesman commented that "Oi is not a word that I would've thought turned up in English manuals all that often." "Oi" was added to the list of acceptable words in US Scrabble in 2006.
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- "Oi (Interjection)" | 2023-12-17 | 43 Upvotes 34 Comments
๐ The fire that has been burning for 56 years
The Centralia mine fire is a coal-seam fire that has been burning underneath the borough of Centralia, Pennsylvania, United States, since at least May 27, 1962. Its original cause is still a matter of debate. It is burning in underground coal mines at depths of up to 300 feet (90ย m) over an 8-mile (13ย km) stretch of 3,700 acres (15ย km2). At its current rate, it could continue to burn for over 250 years. It has caused most of the town to be abandoned: the population dwindled from around 1,500 at the time the fire started to 7 in 2013, and most of the buildings have been levelled.
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- "Pennsylvania town coal mine has been on fire since 1962" | 2021-02-07 | 60 Upvotes 35 Comments
- "The fire that has been burning for 56 years" | 2018-12-13 | 12 Upvotes 5 Comments
๐ Goro Shimura has died
Gorล Shimura (ๅฟๆ ไบ้, Shimura Gorล, 23 February 1930 โ 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 TaniyamaโShimura 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
๐ Russian Web Brigades
Russian web brigades, also called Russian trolls, Russian bots, or more recently Kremlin Bots (after the Kremlin in Moscow) / Kremlins (a pejorative allusion to Gremlin) are state-sponsored anonymous Internet political commentators and trolls linked to the Government of Russia. Participants report that they are organized into teams and groups of commentators that participate in Russian and international political blogs and Internet forums using sockpuppets, social bots and large-scale orchestrated trolling and disinformation campaigns to promote pro-Putin and pro-Russian propaganda. Articles on the Russian Wikipedia concerning the MH17 crash and the 2014 Ukraine conflict were targeted by Russian internet propaganda outlets.
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- "Russian Web Brigades" | 2022-03-12 | 11 Upvotes 1 Comments
๐ Russian Domesticated Red Fox
The Russian domesticated red fox is a form of the wild red fox (Vulpes vulpes) which has been domesticated to an extent, under laboratory conditions. They are the result of an experiment which was designed to demonstrate the power of selective breeding to transform species, as described by Charles Darwin in On the Origin of Species. The experiment was purposely designed to replicate the process that had produced dogs from wolves, by recording the changes in foxes, when in each generation only the most tame foxes were allowed to breed. In short order, the descendant foxes became tamer and more dog-like in their behavior.
The program was started in 1959 in the Soviet Union by zoologist Dmitry Belyayev and it has been in continuous operation since. Today, the experiment is under the supervision of Lyudmila Trut, in Russia, at the Institute of Cytology and Genetics in Novosibirsk.
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- "Russian Domesticated Red Fox" | 2015-11-06 | 96 Upvotes 30 Comments
๐ Lithophone
A lithophone is a musical instrument consisting of a rock or pieces of rock which are struck to produce musical notes. Notes may be sounded in combination (producing harmony) or in succession (melody). The lithophone is an idiophone comparable to instruments such as the glockenspiel, vibraphone, xylophone and marimba.
In the Hornbostel-Sachs classification system, lithophones are designated as '111.22' โ directly-struck percussion plaques.
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- "Lithophone" | 2020-02-22 | 54 Upvotes 7 Comments
๐ Buridan's Ass
Buridan's ass is an illustration of a paradox in philosophy in the conception of free will. It refers to a hypothetical situation wherein an ass that is equally hungry and thirsty is placed precisely midway between a stack of hay and a pail of water. Since the paradox assumes the ass will always go to whichever is closer, it dies of both hunger and thirst since it cannot make any rational decision between the hay and water. A common variant of the paradox substitutes two identical piles of hay for the hay and water; the ass, unable to choose between the two, dies of hunger.
The paradox is named after the 14th-century French philosopher Jean Buridan, whose philosophy of moral determinism it satirizes. Although the illustration is named after Buridan, philosophers have discussed the concept before him, notably Aristotle, who used the example of a man equally hungry and thirsty, and Al-Ghazali, who used a man faced with the choice of equally good dates.
A version of this situation appears as metastability in digital electronics, when a circuit must decide between two states based on an input that is in itself undefined (neither zero nor one). Metastability becomes a problem if the circuit spends more time than it should in this "undecided" state, which is usually set by the speed of the clock the system is using.
๐ CMS Pipelines
CMS Pipelines implements the pipeline concept under the VM/CMS operating system. The programs in a pipeline operate on a sequential stream of records. A program writes records that are read by the next program in the pipeline. Any program can be combined with any other because reading and writing is done through a device independent interface.
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- "CMS Pipelines" | 2016-04-27 | 43 Upvotes 12 Comments