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๐ Agoge
The agลgฤ (Greek: แผฮณฯฮณฮฎ in Attic Greek, or แผฮณฯฮณฮฌ, agลgฤ in Doric Greek) was the rigorous education and training program mandated for all male Spartan citizens, except for the firstborn son in the ruling houses, Eurypontid and Agiad. The training involved cultivating loyalty to the Spartan group, military training (e.g., pain tolerance), hunting, dancing, singing, and social (communicating) preparation. The word agลgฤ had various meaning in ancient Greek, but in this context it generally meant leading, guidance, or training.
According to folklore, agลgฤ was introduced by the semi-mythical Spartan law-giver Lycurgus but its origins are thought to be between the 7th and 6th centuries BC when the state trained male citizens from the ages of seven to twenty-one.
The aim of the system was to produce strong and capable warriors to serve the Spartan army. It encouraged conformity and the importance of the Spartan state over one's personal interest and generated the future elites of Sparta. The men would become the "walls of Sparta" because Sparta was the only Greek city with no defensive walls after they had been demolished at the order of Lycurgus. Discipline was strict and the males were encouraged to fight amongst themselves to determine the strongest member of the group.
The agลgฤ was prestigious throughout the Greek world, and many aristocratic families from other cities vied to send their sons to Sparta to participate in the agลgฤ for varying periods of time. The Spartans were very selective in which young men they would permit to enroll. Such honors were usually awarded to the prรณxenoi (ฯฯฯฮพฮตฮฝฮฟฮน) of Sparta in other cities and to a few other families of supreme ancestry and importance.
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- "Agoge" | 2020-08-26 | 35 Upvotes 31 Comments
๐ Potential Collapse of the West Antarctic Ice Sheet
The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea.
๐ Binaural beats
In acoustics, a beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.
With tuning instruments that can produce sustained tones, beats can be readily recognized. Tuning two tones to a unison will present a peculiar effect: when the two tones are close in pitch but not identical, the difference in frequency generates the beating. The volume varies like in a tremolo as the sounds alternately interfere constructively and destructively. As the two tones gradually approach unison, the beating slows down and may become so slow as to be imperceptible. As the two tones get further apart, their beat frequency starts to approach the range of human pitch perception, the beating starts to sound like a note, and a combination tone is produced. This combination tone can also be referred to as a missing fundamental, as the beat frequency of any two tones is equivalent to the frequency of their implied fundamental frequency.
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- "Binaural beats" | 2013-08-01 | 35 Upvotes 46 Comments
๐ Project Habakkuk, Britain's plan to build an aircraft carrier from ice
Project Habakkuk or Habbakuk (spelling varies) was a plan by the British during the Second World War to construct an aircraft carrier out of pykrete (a mixture of wood pulp and ice) for use against German U-boats in the mid-Atlantic, which were beyond the flight range of land-based planes at that time. The idea came from Geoffrey Pyke, who worked for Combined Operations Headquarters. After promising scale tests and the creation of a prototype on a lake (Patricia Lake, Jasper National Park) in Alberta, Canada, the project was shelved due to rising costs, added requirements, and the availability of longer-range aircraft and escort carriers which closed the Mid-Atlantic gap the project was intended to address.
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- "Project Habakkuk, Britain's plan to build an aircraft carrier from ice" | 2019-01-13 | 13 Upvotes 1 Comments
๐ Hinged dissection
A hinged dissection, also known as a swing-hinged dissection or Dudeney dissection, is a kind of geometric dissection in which all of the pieces are connected into a chain by "hinged" points, such that the rearrangement from one figure to another can be carried out by swinging the chain continuously, without severing any of the connections. Typically, it is assumed that the pieces are allowed to overlap in the folding and unfolding process; this is sometimes called the "wobbly-hinged" model of hinged dissection.
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- "Hinged dissection" | 2013-12-29 | 34 Upvotes 3 Comments
๐ Trancitor
The trancitor as the combined word of a "transfer-capacitor" is to be considered as another active-device category besides the transistor as a "transfer-resistor". As observed in the table shown, four kinds of active devices are theoretically deduced. Among them, trancitors are missing to be the third and fourth kinds, whereas transistors, such as bipolar junction transistor (BJT) and field-effect transistor (FET), were already invented as the first and second kinds, respectively. Unlike the transistor switching the current at its output (i.e., current source), the trancitor transfers its input to the voltage output (i.e., voltage source), so an inverse relationship with each other.
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- "Trancitor" | 2023-07-06 | 24 Upvotes 5 Comments
๐ Korbut Flip
The Korbut flip is a gymnastics skill performed on either of two different apparatus. Both were first performed internationally by the Soviet gymnast Olga Korbut.
The more spectacular version of the skill used to be performed on the uneven bars, where the gymnast, from a stand on the high bar, performs a back flip and regrasps the bar. Korbut performed the move at the 1972 Summer Olympics, where it was the first backward release move performed on the uneven bars in international competition. In 1977, Soviet gymnast Elena Mukhina modified the flip by adding a full twist. The movement was later modified in the 1980s when it was performed towards the low bar; that is, the gymnast's flip takes place above the low bar. The Code of Points was later modified to ban standing on the high bar during routines.
The skill is also performed on the balance beam. The move is performed from a standing position and is landed in a straddled position on the beam. This movement has been modified to include twists and piked or tucked legs and is frequently performed in sequence with other movements. Unlike its counterpart on the uneven bars, the Korbut flip on beam is today considered a relatively simple skill, valued at only a "B" level in the 2017 Code of Points.
Other gymnasts who have performed the skill's uneven bars variation include Radka Zemanova (1980), Steffi Kraker (1977), Emily May (1981), Lyubov Bogdanova (1974) and Natalia Shaposhnikova (1976).
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- "Korbut Flip" | 2023-08-05 | 16 Upvotes 5 Comments
๐ Valid Email Addresses
An email address identifies an email box to which email messages are delivered. A wide variety of formats were used in early email systems, but only a single format is used today, following the specifications developed for Internet mail systems since the 1980s. This article uses the term email address to refer to the addr-spec defined in RFC 5322, not to the address that is commonly used; the difference is that an address may contain a display name, a comment, or both.
An email address such as John.Smith@example.com is made up of a local-part, an @ symbol, then a case-insensitive domain. Although the standard requires the local part to be case-sensitive, it also urges that receiving hosts deliver messages in a case-independent fashion, e.g., that the mail system at example.com treat John.Smith as equivalent to john.smith; some mail systems even treat them as equivalent to johnsmith. Mail systems often limit their users' choice of name to a subset of the technically valid characters, and in some cases also limit which addresses it is possible to send mail to.
With the introduction of internationalized domain names, efforts are progressing to permit non-ASCII characters in email addresses.
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- "Valid Email Addresses" | 2012-11-30 | 50 Upvotes 59 Comments
๐ The Cult of Reason
The Cult of Reason (French: Culte de la Raison) was France's first established state-sponsored atheistic religion, intended as a replacement for Catholicism during the French Revolution. After holding sway for barely a year, in 1794 it was officially replaced by the rival Cult of the Supreme Being, promoted by Robespierre. Both cults were officially banned in 1802 by Napoleon Bonaparte with his Law on Cults of 18 Germinal, Year X.
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- "The Cult of Reason" | 2018-09-15 | 56 Upvotes 25 Comments
๐ Hague Invasion Act
The American Service-Members' Protection Act (ASPA, Title 2 of Pub.L.ย 107โ206 (text) (pdf), H.R. 4775, 116ย Stat.ย 820, enacted August 2, 2002) is a United States federal law that aims "to protect United States military personnel and other elected and appointed officials of the United States government against criminal prosecution by an international criminal court to which the United States is not party." Introduced by U.S. Senator Jesse Helms (R-NC) and U.S. Representative Tom DeLay (R-TX) it was an amendment to the 2002 Supplemental Appropriations Act for Further Recovery From and Response to Terrorist Attacks on the United States (H.R. 4775). The amendment passed 75-19 (S.Amdt 3597.) The bill was signed into law by U.S. President George W. Bush on August 2, 2002.
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- "The Hague Invasion Act" | 2022-05-19 | 13 Upvotes 10 Comments
- "Hague Invasion Act" | 2021-06-12 | 40 Upvotes 12 Comments