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๐Ÿ”— Boreout

๐Ÿ”— Psychology

Boredom boreout syndrome is a psychological disorder that causes physical illness, mainly caused by mental underload at the workplace due to lack of either adequate quantitative or qualitative workload. One reason for bore-out could be that the initial job description does not match the actual work.

This theory was first expounded in 2007 in Diagnose Boreout, a book by Peter Werder and Philippe Rothlin, two Swiss business consultants.


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๐Ÿ”— Bellard's Formula

๐Ÿ”— Mathematics

Bellard's formula is used to calculate the nth digit of ฯ€ in base 16.

Bellard's formula was discovered by Fabrice Bellard in 1997. It is about 43% faster than the Baileyโ€“Borweinโ€“Plouffe formula (discovered in 1995). It has been used in PiHex, the now-completed distributed computing project.

One important application is verifying computations of all digits of pi performed by other means. Rather than having to compute all of the digits twice by two separate algorithms to ensure that a computation is correct, the final digits of a very long all-digits computation can be verified by the much faster Bellard's formula.

Formula:

ฯ€ = 1 2 6 โˆ‘ n = 0 โˆž ( โˆ’ 1 ) n 2 10 n ( โˆ’ 2 5 4 n + 1 โˆ’ 1 4 n + 3 + 2 8 10 n + 1 โˆ’ 2 6 10 n + 3 โˆ’ 2 2 10 n + 5 โˆ’ 2 2 10 n + 7 + 1 10 n + 9 ) {\displaystyle {\begin{aligned}\pi ={\frac {1}{2^{6}}}\sum _{n=0}^{\infty }{\frac {(-1)^{n}}{2^{10n}}}\,\left(-{\frac {2^{5}}{4n+1}}\right.&{}-{\frac {1}{4n+3}}+{\frac {2^{8}}{10n+1}}-{\frac {2^{6}}{10n+3}}\left.{}-{\frac {2^{2}}{10n+5}}-{\frac {2^{2}}{10n+7}}+{\frac {1}{10n+9}}\right)\end{aligned}}}

๐Ÿ”— Bucha Massacre

๐Ÿ”— International relations ๐Ÿ”— Human rights ๐Ÿ”— Russia ๐Ÿ”— Military history ๐Ÿ”— Crime ๐Ÿ”— Death ๐Ÿ”— Ukraine ๐Ÿ”— Russia/Russian, Soviet, and CIS military history ๐Ÿ”— Military history/Russian, Soviet and CIS military history

In March 2022, a series of war crimes were committed by Russian occupation forces in the Ukrainian city of Bucha during the Battle of Bucha, following the Russian invasion of Ukraine. Ukrainian authorities said that more than 300 inhabitants of the town had been killed.

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๐Ÿ”— Burrowsโ€“Wheeler Transform

๐Ÿ”— Molecular Biology ๐Ÿ”— Molecular Biology/Computational Biology

The Burrowsโ€“Wheeler transform (BWT, also called block-sorting compression) rearranges a character string into runs of similar characters. This is useful for compression, since it tends to be easy to compress a string that has runs of repeated characters by techniques such as move-to-front transform and run-length encoding. More importantly, the transformation is reversible, without needing to store any additional data except the position of the first original character. The BWT is thus a "free" method of improving the efficiency of text compression algorithms, costing only some extra computation. The Burrowsโ€“Wheeler transform is an algorithm used to prepare data for use with data compression techniques such as bzip2. It was invented by Michael Burrows and David Wheeler in 1994 while Burrows was working at DEC Systems Research Center in Palo Alto, California. It is based on a previously unpublished transformation discovered by Wheeler in 1983. The algorithm can be implemented efficiently using a suffix array thus reaching linear time complexity.

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๐Ÿ”— Two Generals' Problem

๐Ÿ”— Computing

In computing, the Two Generals' Problem is a thought experiment meant to illustrate the pitfalls and design challenges of attempting to coordinate an action by communicating over an unreliable link. In the experiment, two generals are only able to communicate with one another by sending a messenger through enemy territory. The experiment asks how they might reach an agreement on the time to launch an attack, while knowing that any messenger they send could be captured.

It is related to the more general Byzantine Generals Problem and appears often in introductory classes about computer networking (particularly with regard to the Transmission Control Protocol, where it shows that TCP can't guarantee state consistency between endpoints and why this is the case), though it applies to any type of two-party communication where failures of communication are possible. A key concept in epistemic logic, this problem highlights the importance of common knowledge. Some authors also refer to this as the Two Generals' Paradox, the Two Armies Problem, or the Coordinated Attack Problem. The Two Generals' Problem was the first computer communication problem to be proved to be unsolvable. An important consequence of this proof is that generalizations like the Byzantine Generals problem are also unsolvable in the face of arbitrary communication failures, thus providing a base of realistic expectations for any distributed consistency protocols.

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๐Ÿ”— Wallpaper group

๐Ÿ”— Mathematics

A wallpaper group (or plane symmetry group or plane crystallographic group) is a mathematical classification of a two-dimensional repetitive pattern, based on the symmetries in the pattern. Such patterns occur frequently in architecture and decorative art, especially in textiles and tiles as well as wallpaper.

The simplest wallpaper group, Group p1, applies when there is no symmetry other than the fact that a pattern repeats over regular intervals in two dimensions, as shown in the section on p1 below.

Consider the following examples of patterns with more forms of symmetry:

Examples A and B have the same wallpaper group; it is called p4m in the IUC notation and *442 in the orbifold notation. Example C has a different wallpaper group, called p4g or 4*2 . The fact that A and B have the same wallpaper group means that they have the same symmetries, regardless of details of the designs, whereas C has a different set of symmetries despite any superficial similarities.

The number of symmetry groups depends on the number of dimensions in the patterns. Wallpaper groups apply to the two-dimensional case, intermediate in complexity between the simpler frieze groups and the three-dimensional space groups. Subtle differences may place similar patterns in different groups, while patterns that are very different in style, color, scale or orientation may belong to the same group.

A proof that there were only 17 distinct groups of such planar symmeries was first carried out by Evgraf Fedorov in 1891 and then derived independently by George Pรณlya in 1924. The proof that the list of wallpaper groups was complete only came after the much harder case of space groups had been done. The seventeen possible wallpaper groups are listed below in ยงย The seventeen groups.

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๐Ÿ”— Hawthorne Effect

๐Ÿ”— Mass surveillance ๐Ÿ”— Business ๐Ÿ”— Psychology ๐Ÿ”— Sociology

The Hawthorne effect is a type of human behavior reactivity in which individuals modify an aspect of their behavior in response to their awareness of being observed. The effect was discovered in the context of research conducted at the Hawthorne Western Electric plant; however, some scholars feel the descriptions are apocryphal.

The original research involved workers who made electrical relays at the Hawthorne Works, a Western Electric plant in Cicero, Illinois. Between 1924 and 1927, the lighting study was conducted. Workers experienced a series of lighting changes in which productivity was said to increase with almost any change in the lighting. This turned out not to be true. In the study that was associated with Elton Mayo, which ran from 1928 to 1932, a series of changes in work structure were implemented (e.g., changes in rest periods) in a group of five women. However, this was a methodologically poor, uncontrolled study that did not permit any firm conclusions to be drawn.

One of the later interpretations by Landsberger suggested that the novelty of being research subjects and the increased attention from such could lead to temporary increases in workers' productivity. This interpretation was dubbed "the Hawthorne effect".

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๐Ÿ”— Stu Ungar

๐Ÿ”— Biography ๐Ÿ”— Biography/sports and games ๐Ÿ”— Gambling/Poker ๐Ÿ”— Gambling

Stuart Errol Ungar (September 8, 1953 โ€“ November 22, 1998) was an American professional poker, blackjack, and gin rummy player, widely regarded to have been the greatest Texas hold 'em and gin player of all time.

He is one of two people in poker history to have won the World Series of Poker Main Event three times. He is the only person to win Amarillo Slim's Super Bowl of Poker three times, the world's second most prestigious poker title during its time. He is one of four players in poker history to win consecutive titles in the WSOP Main Event, along with Johnny Moss, Doyle Brunson and Johnny Chan.

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๐Ÿ”— Zero Rupee Note

๐Ÿ”— India ๐Ÿ”— Numismatics ๐Ÿ”— India/Indian politics workgroup

A zero-rupee note is a banknote imitation issued in India as a means of helping to fight systemic political corruption. The notes are "paid" in protest by angry citizens to government functionaries who solicit bribes in return for services which are supposed to be free. Zero rupee notes, which are made to resemble the regular 50 rupee banknote of India, are the creation of a non-governmental organization known as 5th Pillar which has, since their inception in 2007, distributed over 2.5 million notes as of August 2014. The notes remain in current use and thousands of notes are distributed every month.

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๐Ÿ”— List of screw drives

๐Ÿ”— Technology ๐Ÿ”— Canada ๐Ÿ”— Guild of Copy Editors ๐Ÿ”— Engineering

A screw drive is a system used to turn a screw. At a minimum, it is a set of shaped cavities and protrusions on the screw head that allows torque to be applied to it. Usually, it also involves a mating tool, such as a screwdriver, that is used to turn it. The following heads are categorized based on commonality, with some of the less-common drives being classified as "tamper-resistant".

Most heads come in a range of sizes, typically distinguished by a number, such as "Phillips #00". These sizes do not necessarily describe a particular dimension of the drive shape, but rather are arbitrary designations.

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