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🔗 Video games

42 is a private, nonprofit and tuition-free computer programming school created and funded by French billionaire Xavier Niel (founder of the telecommunication company Illiad) with several partners including Nicolas Sadirac (previous director-general of the Epitech school in France), Kwame Yamgnane and Florian Bucher (former executives of Epitech). The school was first opened in Paris in 2013.

Out of more than 80,000 candidates in France, 3,000 were selected to complete a four-week intensive computer programming bootcamp called piscine (swimming-pool). Any person older than 18 can register for the piscine after completing the logical reasoning tests on the website.

The school does not have any professors, and is open 24/7. The training is inspired by new modern ways to teach which include peer-to-peer pedagogy and project-based learning. The School has been endorsed by many high-profile people in Silicon Valley including Evan Spiegel the co-founder and CEO of Snapchat, Keyvon Beykpour the co-founder and CEO of Periscope, Stewart Butterfield the co-founder and CEO of Slack, Brian Chesky the co-founder and CEO of Airbnb, Tony Fadell the founder and CEO of Nest Labs, Jack Dorsey the co-Founder and CEO of Twitter, Paul Graham, venture capitalist and co-Founder of Y Combinator, Bill Gurley venture capitalist and general partner at Benchmark.

The school is a non-profit organization and is entirely free, being funded by billionaire Xavier Niel with hundreds of millions of dollars. All the intellectual property belongs to the students. 42 Silicon Valley is the American campus of 42 chartered as a public-benefit nonprofit corporation in the State of California and has been created and funded by the same team from France, in addition to a new partner, the chief operating officer of the American school and former 42 Paris student Brittany Bir. 42 Silicon Valley opened in summer 2016 in Fremont, California in the San Francisco Bay Area.

42's name is a reference to the science fiction book The Hitchhiker's Guide to the Galaxy written by British author Douglas Adams: in the book 42 is the Answer to the Ultimate Question of Life, the Universe, and Everything.

In addition to the two official campuses in Paris, France and Fremont, California, the school model was adopted in Lyon, Reims, and Mulhouse, France, as well as in Romania, South Africa, Ukraine, Bulgaria, Moldova, Belgium, Russia, Morocco, the Netherlands, Indonesia, and Finland with the help and support of 42.

🔗 Urban studies and planning

Marchetti's constant is the average time spent by a person for commuting each day, which is approximately one hour. It is named after Italian physicist Cesare Marchetti, though Marchetti himself attributed the "one hour" finding to transportation analyst and engineer Yacov Zahavi. Marchetti posits that although forms of urban planning and transport may change, and although some live in villages and others in cities, people gradually adjust their lives to their conditions (including location of their homes relative to their workplace) such that the average travel time stays approximately constant. Ever since Neolithic times, people have kept the average time spent per day for travel the same, even though the distance may increase due to the advancements in the means of transportation. In his 1934 book Technics and Civilization, Lewis Mumford attributes this observation to Bertrand Russell:

Mr. Bertrand Russell has noted that each improvement in locomotion has increased the area over which people are compelled to move: so that a person who would have had to spend half an hour to walk to work a century ago must still spend half an hour to reach his destination, because the contrivance that would have enabled him to save time had he remained in his original situation now—by driving him to a more distant residential area—effectually cancels out the gain.

A related concept is that of Zahavi, who also noticed that people seem to have a constant "travel time budget", that is, "a stable daily amount of time that people make available for travel." David Metz, former chief scientist at the Department of Transport, UK, cites data of average travel time in Britain drawn from the British National Travel Survey in support of Marchetti's and Zahavi's conclusions. The work casts doubt on the contention that investment in infrastructure saves travel time. Instead, it appears from Metz's figures that people invest travel time saved in travelling a longer distance, a particular example of Jevons paradox described by the Lewis–Mogridge position. Because of the constancy of travel times as well as induced travel, Robert Cervero has argued that the World Bank and other international aid agencies evaluate transportation investment proposals in developing and rapidly motorizing cities less on the basis of potential travel-time savings and more on the accessibility benefits they confer.

🔗 France

La Bougie du Sapeur (French: [la bu.ʒi dy sa.pœʁ]) is a French satirical newspaper launched in 1980 that is published only on Leap Day, making it the world's least frequently published newspaper. The editor-in-chief is Jean d'Indy, who works for France Galop and has been involved in producing the paper since 1992.

🔗 Occupational Safety and Health

Lock Out, Tag Out (LOTO), Lock Out, Tag Out, Try Out (LOTOTO) or lock and tag is a safety procedure used in industry and research settings to ensure that dangerous machines are properly shut off and not able to be started up again prior to the completion of maintenance or repair work. It requires that hazardous energy sources be "isolated and rendered inoperative" before work is started on the equipment in question. The isolated power sources are then locked and a tag is placed on the lock identifying the worker who placed it. The worker then holds the key for the lock, ensuring that only he or she can remove the lock and start the machine. This prevents accidental startup of a machine while it is in a hazardous state or while a worker is in direct contact with it.

Lockout-tagout is used across industries as a safe method of working on hazardous equipment and is mandated by law in some countries.

🔗 Spaceflight

SNAP-10A (Systems for Nuclear, Auxiliary Power, aka Snapshot for Space Nuclear Auxiliary Power Shot, also known as OPS 4682, COSPAR 1965-027A) was a US experimental nuclear powered satellite launched into space in 1965 as part of the SNAPSHOT program. The test marked the world's first operation of a nuclear reactor in orbit, and also the first operation of an ion thruster system in orbit. It is the only fission reactor power system launched into space by the United States. The reactor stopped working after just 43 days due to a non-nuclear electrical component failure. The Systems Nuclear Auxiliary Power Program (SNAP) reactor was specifically developed for satellite use in the 1950s and early 1960s under the supervision of the U.S. Atomic Energy Commission.

🔗 Biology 🔗 Genetics 🔗 Computational Biology 🔗 Evolutionary biology 🔗 Human Genetic History

The last universal common ancestor (LUCA), also called the last universal ancestor (LUA), or concestor, is the most recent population of organisms from which all organisms now living on Earth have a common descent, the most recent common ancestor of all current life on Earth. (A related concept is that of progenote.) LUCA is not thought to be the first life on Earth but only one of many early organisms, all the others becoming extinct.

While there is no specific fossil evidence of LUCA, it can be studied by comparing the genomes of all modern organisms, its descendants. By this means, a 2016 study identified a set of 355 genes most likely to have been present in LUCA. (However, some of those genes could have developed later, then spread universally by horizontal gene transfer between archaea and bacteria.) The genes describe a complex life form with many co-adapted features, including transcription and translation mechanisms to convert information from DNA to RNA to proteins. The study concluded that the LUCA probably lived in the high-temperature water of deep sea vents near ocean-floor magma flows.

Studies from 2000 to 2018 have suggested an increasingly ancient time for LUCA. In 2000, estimations suggested LUCA existed 3.5 to 3.8 billion years ago in the Paleoarchean era, a few hundred million years after the earliest fossil evidence of life, for which there are several candidates ranging in age from 3.48 to 4.28 billion years ago. A 2018 study from the University of Bristol, applying a molecular clock model, places the LUCA shortly after 4.5 billion years ago, within the Hadean.

Charles Darwin first proposed the theory of universal common descent through an evolutionary process in his book On the Origin of Species in 1859: "Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed." Later biologists have separated the problem of the origin of life from that of the LUCA.

🔗 Disaster management 🔗 Economics 🔗 Urban studies and planning

The great horse manure crisis of 1894 refers to the idea that the greatest obstacle to urban development at the turn of the century was the difficulty of removing horse manure from the streets. More broadly, it is an analogy for supposedly insuperable extrapolated problems being rendered moot by the introduction of new technologies. The phrase originates from a 2004 article by Stephen Davies entitled "The Great Horse-Manure Crisis of 1894".

The supposed problem of excessive horse-manure collecting in the streets was solved by the proliferation of cars, buses and electrified trams which replaced horses as the means of transportation in big cities. The term great horse manure crisis of 1894 is often used to denote a problem which seems to be impossible to solve because it is being looked at from the wrong direction.

The name refers to a supposed 1894 publication in The Times, which said "In 50 years, every street in London will be buried under nine feet of manure". The reasoning was that more horses are needed to remove the manure, and these horses produce more manure. An urban planning conference in 1898 supposedly broke up before its scheduled end due to a failure to find an answer to this problem. No such statement in the Times, nor conference result, is known, but in 1893 London there was a complaint that horse manure, formerly an economic good that could be sold, had become a disposal problem, an economic bad.

The supposed crisis has since taken on life as a useful analogy.

🔗 Mexico 🔗 Archaeology 🔗 Mesoamerica

The Great Pyramid of Cholula, also known as Tlachihualtepetl (Nahuatl for "made-by-hand mountain"), is a complex located in Cholula, Puebla, Mexico. It is the largest archaeological site of a pyramid (temple) in the New World, as well as the largest pyramid by volume known to exist in the world today. The adobe brick pyramid stands 25 metres (82 ft) above the surrounding plain, which is significantly shorter than the Great Pyramid of Giza's height of 146.6 metres (481 ft), but much wider, measuring 300 by 315 metres (984 by 1,033 ft) in its final form, compared to the Great Pyramid's base dimensions of 230.3 by 230.3 metres (756 by 756 ft). The pyramid is a temple that traditionally has been viewed as having been dedicated to the god Quetzalcoatl. The architectural style of the building was linked closely to that of Teotihuacan in the Valley of Mexico, although influence from the Gulf Coast is evident as well, especially from El Tajín.

🔗 China 🔗 Languages 🔗 Hong Kong

"Add oil" is a Hong Kong English expression used as an encouragement and support to a person. Derived from the Chinese phrase Gayau (or Jiayou; Chinese: 加油), the expression is literally translated from the Cantonese phrase. It is originated in Hong Kong and is commonly used by bilingual Hong Kong speakers.

"Add oil" can be roughly translated as "Go for it". Though it is often described as "the hardest to translate well", the literal translation is the result of Chinglish and was added to the Oxford English Dictionary in 2018.

🔗 Mathematics 🔗 Statistics

In the design of experiments in statistics, the lady tasting tea is a randomized experiment devised by Ronald Fisher and reported in his book The Design of Experiments (1935). The experiment is the original exposition of Fisher's notion of a null hypothesis, which is "never proved or established, but is possibly disproved, in the course of experimentation".

The example is loosely based on an event in Fisher's life. The woman in question, phycologist Muriel Bristol, claimed to be able to tell whether the tea or the milk was added first to a cup. Her future husband, William Roach, suggested that Fisher give her eight cups, four of each variety, in random order. One could then ask what the probability was for her getting the specific number of cups she identified correct (in fact all eight), but just by chance.

Fisher's description is less than 10 pages in length and is notable for its simplicity and completeness regarding terminology, calculations and design of the experiment. The test used was Fisher's exact test.