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๐Ÿ”— Cafe Mediterraneum

๐Ÿ”— California ๐Ÿ”— California/San Francisco Bay Area ๐Ÿ”— Food and drink

Caffรจ Mediterraneum, often referred to as Caffรจ Med or simply the Med, was a cafรฉ located on Telegraph Avenue in Berkeley, California, US, near the University of California, Berkeley. The Med was a landmark of Telegraph Avenue history, "listed for years in European guidebooks as 'the gathering place for 1960s radicals who created People's Park'" and as of 2009 described in Fodor's guidebook as "a relic of 1960s-era cafรฉ culture". It was located at 2475 Telegraph Avenue, between Dwight Way and Haste Street.

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๐Ÿ”— Albert Stevens

๐Ÿ”— Biography

Albert Stevens (1887โ€“1966), also known as patient CAL-1, was a victim of a human radiation experiment, and survived the highest known accumulated radiation dose in any human. On May 14, 1945, he was injected with 131 kBq (3.55 ยตCi) of plutonium without his knowledge or informed consent.

Plutonium remained present in his body for the remainder of his life, the amount decaying slowly through radioactive decay and biological elimination. Stevens died of heart disease some 20 years later, having accumulated an effective radiation dose of 64 Sv (6400 rem) over that period, i.e. an average of 3 Sv per year or 350ย ฮผSv/h. The current annual permitted dose for a radiation worker in the United States is 0.05 Sv (or 5 rem), i.e. an average of 5.7 ฮผSv/h.

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๐Ÿ”— Crew resource management

๐Ÿ”— Aviation ๐Ÿ”— Disaster management

Crew resource management or cockpit resource management (CRM) is a set of training procedures for use in environments where human error can have devastating effects. Used primarily for improving aviation safety, CRM focuses on interpersonal communication, leadership, and decision making in the cockpit of an airliner. Its pioneer was David Beaty, a former Royal Air Force pilot and later a BOAC pilot who wrote his seminal book The Human Factor in Aircraft Accidents in the late 1950s. Despite the considerable development of electronic aids since then, many principles he developed continue to prove effective today.

Crew resource management formally began with a National Transportation Safety Board (NTSB) recommendation made during their investigation of the 1978 United Airlines Flight 173 crash. The issues surrounding that crash included a DC-8 crew running out of fuel over Portland, Oregon while troubleshooting a landing gear problem.

The term "cockpit resource management" (later generalized to "crew resource management") was coined in 1979 by NASA psychologist John Lauber who had studied communication processes in cockpits for several years. While retaining a command hierarchy, the concept was intended to foster a less authoritarian cockpit culture, where co-pilots were encouraged to question captains if they observed them making mistakes.

Crew resource management grew out of the 1977 Tenerife airport disaster where two Boeing 747 aircraft collided on the runway killing 583 people. A few weeks later, NASA held a workshop on the topic, endorsing this innovative training. United Airlines was the first airline to provide CRM training for its cockpit crews in 1981. By the 1990s, it had become a global standard.

United Airlines additionally trained their flight attendants to use CRM in conjunction with the pilots to provide another layer of enhanced communication and teamwork. Studies have shown that by both work groups using CRM together, communication barriers are reduced and problems can be solved more efficiently, leading to increased safety. CRM training concepts have been modified for application to a wide range of activities where people must make dangerous time-critical decisions. These arenas include air traffic control, ship handling, firefighting, and medical operating rooms.

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๐Ÿ”— Luhn Algorithm for validating credit cards

๐Ÿ”— Computing ๐Ÿ”— Mathematics

The Luhn algorithm or Luhn formula, also known as the "modulus 10" or "mod 10" algorithm, named after its creator, IBM scientist Hans Peter Luhn, is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers in the United States, Canadian Social Insurance Numbers, Israel ID Numbers, South African ID Numbers, Greek Social Security Numbers (ฮ‘ฮœฮšฮ‘), and survey codes appearing on McDonald's, Taco Bell, and Tractor Supply Co. receipts. It is described in U.S. Patent No. 2,950,048, filed on January 6, 1954, and granted on August 23, 1960.

The algorithm is in the public domain and is in wide use today. It is specified in ISO/IEC 7812-1. It is not intended to be a cryptographically secure hash function; it was designed to protect against accidental errors, not malicious attacks. Most credit cards and many government identification numbers use the algorithm as a simple method of distinguishing valid numbers from mistyped or otherwise incorrect numbers.

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๐Ÿ”— Letterlocking (Wikipedia)

๐Ÿ”— Philately

Letterlocking is the act of folding and securing a written message which could be on papyrus, parchment, or paper, so that it does not require an envelope or additional enclosure. It is a document security tradition which utilizes folding and cutting. The process dates to the 13th century in Western history, corresponding with the availability of flexible writing paper. Letterlocking uses small slits, tab, and holes placed directly into a letter, which combined with folding techniques are used to secure the letter ("letterpacket"), preventing reading the letter without breaking seals or slips, providing a means of tamper resistance. These folds and holes may be additionally secured with string and sealing wax. A Scottish diplomat in Italy, William Keith of Delny, sent letters to James VI of Scotland which would tear in two if not opened with care.

Intricate letterlocking works contain artistic elements, demonstrating more than a utilitarian purpose. While the use of sealing techniques may have been limited to ecclesiastic and the nobility, letterlocking was historically performed by all classes of writers. An individual could also be recognised by their personal technique of folding, as was the case with Jane Whorwood, of whose letter Charles I, imprisoned in Carisbrooke Castle on the Isle of Wight, wrote: "This Note [...] I know, by the fowldings [...] that it is written by [Mrs Whorwood]".

Letterlocking is also a discipline focusing on "the materially engineered security and privacy of letters, both as a technology and a historically evolving tradition."

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๐Ÿ”— Mars will have a 420 day since it has a 668 days a year

๐Ÿ”— Time ๐Ÿ”— Solar System/Mars ๐Ÿ”— Solar System

Various schemes have been used or proposed for timekeeping on the planet Mars independently of Earth time and calendars.

Mars has an axial tilt and a rotation period similar to those of Earth. Thus, it experiences seasons of spring, summer, autumn and winter much like Earth. Coincidentally, the duration of a Martian day is within a few percent of that of an Earth day, which has led to the use of analogous time units. A Mars year is almost twice as long as Earth's, and its orbital eccentricity is considerably larger, which means that the lengths of various Martian seasons differ considerably, and sundial time can diverge from clock time more than on Earth.

๐Ÿ”— Williams syndrome

๐Ÿ”— Medicine ๐Ÿ”— Medicine/Neurology ๐Ÿ”— Medicine/Medical genetics

Williams syndrome (WS) is a genetic disorder that affects many parts of the body. Facial features frequently include a broad forehead, short nose and full cheeks, an appearance that has been described as "elfin". While mild to moderate intellectual disability with particular problems with visual spatial tasks such as drawing is typical, verbal skills are generally relatively unaffected. Those affected often have an outgoing personality, interact readily with strangers, and appear happy. Problems with teeth, heart problems, especially supravalvular aortic stenosis, and periods of high blood calcium are common.

Williams syndrome is caused by a genetic abnormality, specifically a deletion of about 27 genes from the long arm of one of the two chromosome 7s. Typically this occurs as a random event during the formation of the egg or sperm from which a person develops. In a small number of cases, it is inherited from an affected parent in an autosomal dominant manner. The different characteristic features have been linked to the loss of specific genes. The diagnosis is typically suspected based on symptoms and confirmed by genetic testing.

Treatment includes special education programs and various types of therapy. Surgery may be done to correct heart problems. Dietary changes or medications may be required for high blood calcium. The syndrome was first described in 1961 by New Zealander John C. P. Williams. Williams syndrome affects between 1 in 7,500 to 1 in 20,000 people at birth. Life expectancy is less than that of the general population, mostly due to the increased rates of heart disease.

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๐Ÿ”— Newcomb's paradox

๐Ÿ”— Philosophy ๐Ÿ”— Philosophy/Logic ๐Ÿ”— Game theory

In philosophy and mathematics, Newcomb's paradox, also referred to as Newcomb's problem, is a thought experiment involving a game between two players, one of whom is able to be able to predict the future.

Newcomb's paradox was created by William Newcomb of the University of California's Lawrence Livermore Laboratory. However, it was first analyzed in a philosophy paper by Robert Nozick in 1969, and appeared in the March 1973 issue of Scientific American, in Martin Gardner's "Mathematical Games." Today it is a much debated problem in the philosophical branch of decision theory.

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๐Ÿ”— Counting rods

๐Ÿ”— China

Counting rods (traditional Chinese: ็ฑŒ; simplified Chinese: ็ญน; pinyin: chรณu; Japanese: ็ฎ—ๆœจ; rลmaji: sangi; Korean: sangaji) are small bars, typically 3โ€“14ย cm long, that were used by mathematicians for calculation in ancient East Asia. They are placed either horizontally or vertically to represent any integer or rational number.

The written forms based on them are called rod numerals. They are a true positional numeral system with digits for 1โ€“9 and a blank for 0, from the Warring states period (circa 475 BCE) to the 16th century.