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π Ultraviolet catastrophe
The ultraviolet catastrophe, also called the RayleighβJeans catastrophe, was the prediction of late 19th century to early 20th century classical physics that an ideal black body at thermal equilibrium would emit an unbounded quantity of energy as wavelength decreased into the ultraviolet range.:β6β7β The term "ultraviolet catastrophe" was first used in 1911 by Paul Ehrenfest, but the concept originated with the 1900 statistical derivation of the RayleighβJeans law.
The phrase refers to the fact that the empirically derived RayleighβJeans law, which accurately predicted experimental results at large wavelengths, failed to do so for short wavelengths. (See the image for further elaboration.) As the theory diverged from empirical observations when these frequencies reached the ultraviolet region of the electromagnetic spectrum, there was a problem. This problem was later found to be due to a property of quanta as proposed by Max Planck: There could be no fraction of a discrete energy package already carrying minimal energy.
Since the first use of this term, it has also been used for other predictions of a similar nature, as in quantum electrodynamics and such cases as ultraviolet divergence.
Discussed on
- "Ultraviolet catastrophe" | 2024-04-03 | 12 Upvotes 2 Comments
π Velotype Keyboard
Velotype is the trademark for a type of keyboard for typing text known as a syllabic chord keyboard, an invention of the Dutchmen Nico Berkelmans and Marius den Outer.
Discussed on
- "Velotype Keyboard" | 2024-04-04 | 17 Upvotes 1 Comments
π Human Anti-Mouse Antibody
Human anti-mouse antibody or human anti-murine antibody (HAMA) is an antibody found in humans which reacts to immunoglobins found in mice.
π Artificio de Juanelo
The Artificio de Juanelo ("Gianello's artifice") was the name of two devices built in Toledo in the 16th century by Juanelo Turriano. They were designed to supply the city with a source of readily available water by lifting it from the Tagus (Tajo) river to the AlcΓ‘zar. Now in ruins, the precise details of the operation of the devices are unknown, but at the time they were considered engineering wonders.
Discussed on
- "Artificio de Juanelo" | 2024-04-02 | 96 Upvotes 11 Comments
π Los Alamos Chess
Los Alamos chess (or anti-clerical chess) is a chess variant played on a 6Γ6 board without bishops. This was the first chess-like game played by a computer program. This program was written at Los Alamos Scientific Laboratory by Paul Stein and Mark Wells for the MANIAC I computer in 1956. The reduction of the board size and the number of pieces from standard chess was due to the very limited capacity of computers at the time.
The program was very simple, containing only about 600 instructions. It was mostly a minimax tree search and could look four plies ahead. For scoring the board at the end of the four-ply lookahead, it estimates a score for material and a score for mobility, then adds them up. Pseudocode for the chess program is described in Figure 11.4 of Newell, 2019. In 1958, a revised version was written for MANIAC II for full 8Γ8 chess, though its pseudocode was never published. There is a record of a single game by it, circa November 1958 (Table 11.2 of Newell, 2019).
Discussed on
- "Los Alamos Chess" | 2024-04-02 | 265 Upvotes 107 Comments
π Snottite
Snottite, also snoticle, is a microbial mat of single-celled extremophilic bacteria which hang from the walls and ceilings of caves and are similar to small stalactites, but have the consistency of nasal mucus. In the Frasassi Caves in Italy, over 70% of cells in Snottite have been identified as Acidithiobacillus thiooxidans, with smaller populations including an archaeon in the uncultivated 'G-plasma' clade of Thermoplasmatales (>15%) and a bacterium in the Acidimicrobiaceae family (>5%).
The bacteria derive their energy from chemosynthesis of volcanic sulfur compounds including H2S and warm-water solution dripping down from above, producing sulfuric acid. Because of this, their waste products are highly acidic (approaching pH=0), with similar properties to battery acid. Researchers at the University of Texas have suggested that this sulfuric acid may be a more significant cause of cave formation than the usual explanation offered of the carbonic acid formed from carbon dioxide dissolved in water.
Snottites were brought to attention by researchers Diana Northup and Penny Boston studying them (and other organisms) in a toxic sulfur cave called Cueva de Villa Luz (Cave of the Lighted House), in Tabasco, Mexico. Snottites were first discovered in this cave by Jim Pisarowicz in 1986, who also coined the term.
The BBC series Wonders of the Solar System saw Professor Brian Cox examining snottites and positing that if there is life on Mars, it may be similarly primitive and hidden beneath the surface of the Red Planet.
Discussed on
- "Snottite" | 2024-04-02 | 57 Upvotes 9 Comments
π Pareto Front
In multi-objective optimization, the Pareto front (also called Pareto frontier or Pareto curve) is the set of all Pareto efficient solutions. The concept is widely used in engineering.:β111β148β It allows the designer to restrict attention to the set of efficient choices, and to make tradeoffs within this set, rather than considering the full range of every parameter.:β63β65β:β399β412β
π First Council of Nicaea
The First Council of Nicaea ( ny-SEE-Ι; Ancient Greek: Ξ£ΟΞ½ΞΏΞ΄ΞΏΟ ΟαΏΟ ΞΞΉΞΊΞ±Ξ―Ξ±Ο, romanized:Β SΓ½nodos tΓͺs NikaΓas) was a council of Christian bishops convened in the Bithynian city of Nicaea (now Δ°znik, Turkey) by the Roman Emperor Constantine I. The Council of Nicaea met from May until the end of July 325.
This ecumenical council was the first of many efforts to attain consensus in the church through an assembly representing all Christendom. Hosius of Corduba may have presided over its deliberations. Its main accomplishments were settlement of the Christological issue of the divine nature of God the Son and his relationship to God the Father, the construction of the first part of the Nicene Creed, mandating uniform observance of the date of Easter, and promulgation of early canon law.
Discussed on
- "First Council of Nicaea" | 2024-03-31 | 32 Upvotes 51 Comments
π Kilroy Was Here
Kilroy was here is a meme that became popular during World War II, typically seen in graffiti. Its origin is debated, but the phrase and the distinctive accompanying doodle became associated with GIs in the 1940s: a bald-headed man (sometimes depicted as having a few hairs) with a prominent nose peeking over a wall with his fingers clutching the wall.
"Mr Chad" or just "Chad" was the version that became popular in the United Kingdom. The character of Chad may have been derived from a British cartoonist in 1938, possibly pre-dating "Kilroy was here". According to Dave Wilton, "Some time during the war, Chad and Kilroy met, and in the spirit of Allied unity merged, with the British drawing appearing over the American phrase." Other names for the character include Smoe, Clem, Flywheel, Private Snoops, Overby, Eugene the Jeep, Scabooch, and Sapo.
According to Charles Panati, "The outrageousness of the graffiti was not so much what it said, but where it turned up." It is not known if there was an actual person named Kilroy who inspired the graffiti, although there have been claims over the years.
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- "Kilroy Was Here" | 2024-03-31 | 26 Upvotes 5 Comments
π 20 years ago Far Cry was released
Far Cry is a 2004 first-person shooter game developed by Crytek and published by Ubisoft. It is the first installment in the Far Cry franchise. Set on a mysterious tropical archipelago, the game follows Jack Carver, a former American special operations forces operative, as he searches for journalist Valerie Constantine, who accompanied him to the islands but went missing after their boat was destroyed by mercenaries. As Jack explores the islands, he begins to discover the horrific genetic experiments being conducted on the local wildlife and must confront the mad scientist behind them.
The game was the first to use Crytek's CryEngine, and was designed as an open-ended first-person shooter, though it lacks most of the freedom its successors would offer to the player. While players can freely explore the game's world like in later Far Cry titles, they are most often discouraged from doing so due to the linear structure of missions and the lack of side content. Despite this, the gameplay formula established in Far Cryβplacing the player in a foreign environment occupied by enemy forces where they must use various weapons and tools, as well as their surroundings to overcome any threatβwould prove essential in defining the series' identity going forward.
Far Cry was released for Microsoft Windows in March 2004 to generally positive reviews, being praised for its visuals, gameplay mechanics, and the level of freedom given to players. The game was also a commercial success, selling over 730,000 units within four months of release and over 2.5 million units in its lifetime. The success of Far Cry led to a series of standalone sequels developed by Ubisoft, starting with Far Cry 2 in 2008. A remake of the game with a different storyline and new mechanics, Far Cry Instincts, was released for the Xbox in 2005, and for the Xbox 360 in 2006 as part of the Far Cry Instincts: Predator compilation. A loose film adaptation was released in 2008. The original version of Far Cry, updated with HD graphics, was re-released under the title Far Cry Classic for the PlayStation 3 and Xbox 360 in 2014.
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- "20 years ago Far Cry was released" | 2024-03-30 | 70 Upvotes 63 Comments