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π 1961 Goldsboro B-52 crash
The 1961 Goldsboro B-52 crash was an accident that occurred near Goldsboro, North Carolina, on 23 January 1961. A Boeing B-52 Stratofortress carrying two 3β4-megaton Mark 39 nuclear bombs broke up in mid-air, dropping its nuclear payload in the process. The pilot in command, Walter Scott Tulloch, ordered the crew to eject at 9,000 feet (2,700Β m). Five crewmen successfully ejected or bailed out of the aircraft and landed safely, another ejected, but did not survive the landing, and two died in the crash. Information declassified in 2013 showed that one of the bombs came very close to detonating.
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- "1961 Goldsboro B-52 crash" | 2016-12-16 | 10 Upvotes 3 Comments
π Super-Spreader
A super-spreader is an unusually contagious organism infected with a disease. In context of a human-borne illness, a super-spreader is an individual who is more likely to infect others, compared with a typical infected person. Such super-spreaders are of particular concern in epidemiology.
Some cases of super-spreading conform to the 80/20 rule, where approximately 20% of infected individuals are responsible for 80% of transmissions, although super-spreading can still be said to occur when super-spreaders account for a higher or lower percentage of transmissions. In epidemics with super-spreading, the majority of individuals infect relatively few secondary contacts.
Super-spreading events are shaped by multiple factors including a decline in herd immunity, nosocomial infections, virulence, viral load, misdiagnosis, airflow dynamics, immune suppression, and co-infection with another pathogen.
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- "Super-Spreader" | 2020-01-22 | 30 Upvotes 8 Comments
π The Battle of Palmdale
The Battle of Palmdale was the attempted shoot-down of a runaway drone by United States Air Force interceptors in the skies over Southern California in mid-August 1956. The drone was launched from Point Mugu Naval Air Station and soon went out of control. Interceptor aircraft took off from Oxnard Air Force Base and caught up with the drone, but were ultimately unable to bring it down, in spite of expending all of their rockets. After it ran out of fuel, the unmanned aircraft crashed in a sparsely populated tract of desert.
During the incident over 1000 acres were scorched and a substantial amount of property was damaged or destroyed.
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- "The Battle of Palmdale" | 2016-07-17 | 60 Upvotes 13 Comments
π Shunting-yard algorithm
In computer science, the shunting-yard algorithm is a method for parsing mathematical expressions specified in infix notation. It can produce either a postfix notation string, also known as Reverse Polish notation (RPN), or an abstract syntax tree (AST). The algorithm was invented by Edsger Dijkstra and named the "shunting yard" algorithm because its operation resembles that of a railroad shunting yard. Dijkstra first described the Shunting Yard Algorithm in the Mathematisch Centrum report MR 34/61.
Like the evaluation of RPN, the shunting yard algorithm is stack-based. Infix expressions are the form of mathematical notation most people are used to, for instance "3 + 4" or "3 + 4 Γ (2 β 1)". For the conversion there are two text variables (strings), the input and the output. There is also a stack that holds operators not yet added to the output queue. To convert, the program reads each symbol in order and does something based on that symbol. The result for the above examples would be (in Reverse Polish notation) "3 4 +" and "3 4 2 1 β Γ +", respectively.
The shunting-yard algorithm was later generalized into operator-precedence parsing.
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- "Shunting-yard algorithm" | 2019-02-18 | 75 Upvotes 26 Comments
π Agglutinative Language
An agglutinative language is a type of synthetic language with morphology that primarily uses agglutination. Words may contain different morphemes to determine their meanings, but all of these morphemes (including stems and affixes) remain, in every aspect, unchanged after their unions. This results in generally more easily deducible word meanings if compared to fusional languages, which allow modifications in either or both the phonetics or spelling of one or more morphemes within a word. This usually results in a shortening of the word, or it provides easier pronunciation.
Agglutinative languages have generally one grammatical category per affix while fusional languages have multiple. The term was introduced by Wilhelm von Humboldt to classify languages from a morphological point of view. It is derived from the Latin verb agglutinare, which means "to glue together".
Non-agglutinative synthetic languages are fusional languages; morphologically, they combine affixes by "squeezing" them together, drastically changing them in the process, and joining several meanings in a single affix (for example, in the Spanish word comΓ "I ate", the suffix -Γ carries the meanings of first person, singular number, past tense, perfective aspect, indicative mood, active voice.) The term agglutinative is sometimes incorrectly used as a synonym for synthetic. Used in this way, the term embraces both fusional languages and inflected languages. The agglutinative and fusional languages are two ends of a continuum, with various languages falling more toward one or the other end. For example, Japanese is generally agglutinative, but displays fusion in otΕto (εΌ, younger brother), from oto+hito (originally woto+pito), and in its non-affixing verb conjugations. A synthetic language may use morphological agglutination combined with partial usage of fusional features, for example in its case system (e.g., German, Dutch, and Persian).
Agglutinative languages tend to have a high rate of affixes or morphemes per word, and to be very regular, in particular with very few irregular verbs. For example, Japanese has very few irregular verbs β only two are significantly irregular, and there are only about a dozen others with only minor irregularity; Ganda has only one (or two, depending on how "irregular" is defined); while in the Quechua languages, all the ordinary verbs are regular. Korean has only ten irregular forms of conjugation except for the passive and causative conjugations. Georgian is an exception; it is highly agglutinative (with up to eight morphemes per word), but it has a significant number of irregular verbs with varying degrees of irregularity.
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- "Agglutinative Language" | 2019-11-19 | 59 Upvotes 29 Comments
π Abraham Lempel (LZ77) has died
Abraham Lempel (Hebrew: ΧΧΧ¨ΧΧ ΧΧΧ€Χ, 10 February 1936 β 4 February 2023) was an Israeli computer scientist and one of the fathers of the LZ family of lossless data compression algorithms.
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- "RIP Abraham Lempel β one of the fathers of the LZ(ZIP) compression algorithms" | 2023-02-06 | 12 Upvotes 2 Comments
π Xeer
Xeer (pronounced [Δ§eΛr]) is the traditional legal system of Somalia, and one of the three systems from which formal Somali law draws its inspiration, the others being civil law and Islamic law. It is believed to pre-date Islam, although it was influenced by Islam and retains many of the faith's conservative elements. Under this system, elders, known as the xeer begti serve as mediator judges and help settle court cases, taking precedent and custom into account. Xeer is polycentric in that different groups within Somali society have different interpretations of xeer.
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- "Xeer" | 2014-05-13 | 246 Upvotes 117 Comments
π Blue Peacock
Blue Peacock, renamed from Blue Bunny and originally Brown Bunny, was a British tactical nuclear weapon project in the 1950s.
The project's goal was to store a number of ten-kiloton nuclear mines in Germany, to be placed on the North German Plain and, in the event of Soviet invasion from the east, detonated by wire or an eight-day timer to:
...Β not only destroy facilities and installations over a large area, butΒ ... deny occupation of the area to an enemy for an appreciable time due to contaminationΒ ...
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- "Blue Peacock" | 2019-09-23 | 56 Upvotes 8 Comments
π DjVu, an open PDF alternative
DjVu ( DAY-zhah-VOO, like French "dΓ©jΓ vu") is a computer file format designed primarily to store scanned documents, especially those containing a combination of text, line drawings, indexed color images, and photographs. It uses technologies such as image layer separation of text and background/images, progressive loading, arithmetic coding, and lossy compression for bitonal (monochrome) images. This allows high-quality, readable images to be stored in a minimum of space, so that they can be made available on the web.
DjVu has been promoted as providing smaller files than PDF for most scanned documents. The DjVu developers report that color magazine pages compress to 40β70Β kB, black-and-white technical papers compress to 15β40Β kB, and ancient manuscripts compress to around 100Β kB; a satisfactory JPEG image typically requires 500Β kB. Like PDF, DjVu can contain an OCR text layer, making it easy to perform copy and paste and text search operations.
Free creators, manipulators, converters, browser plug-ins, and desktop viewers are available. DjVu is supported by a number of multi-format document viewers and e-book reader software on Linux (Okular, Evince), Windows (SumatraPDF), Android (EBookDroid, PocketBook).
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- "DjVu - PDF alternative" | 2024-04-10 | 17 Upvotes 1 Comments
- "DjVu, an open PDF alternative" | 2018-06-30 | 143 Upvotes 98 Comments
π Buddhas of Bamiyan
The Buddhas of Bamiyan were two 6th-century monumental statues of Vairocana Buddha and Gautama Buddha carved into the side of a cliff in the Bamyan valley of central Afghanistan, 130 kilometres (81Β mi) northwest of Kabul at an elevation of 2,500 metres (8,200Β ft). Carbon dating of the structural components of the Buddhas has determined that the smaller 38Β m (125Β ft) "Eastern Buddha" was built around 570 AD, and the larger 55Β m (180Β ft) "Western Buddha" was built around 618 AD.
The statues represented a later evolution of the classic blended style of Gandhara art. The statues consisted of the male Salsal ("light shines through the universe") and the (smaller) female Shamama ("Queen Mother"), as they were called by the locals. The main bodies were hewn directly from the sandstone cliffs, but details were modeled in mud mixed with straw, coated with stucco. This coating, practically all of which wore away long ago, was painted to enhance the expressions of the faces, hands, and folds of the robes; the larger one was painted carmine red and the smaller one was painted multiple colors. The lower parts of the statues' arms were constructed from the same mud-straw mix supported on wooden armatures. It is believed that the upper parts of their faces were made from great wooden masks or casts. The rows of holes that can be seen in photographs held wooden pegs that stabilized the outer stucco.
The Buddhas are surrounded by numerous caves and surfaces decorated with paintings. It is thought that the period of florescence was from the 6th to 8th century AD, until the onset of Islamic invasions. These works of art are considered as an artistic synthesis of Buddhist art and Gupta art from India, with influences from the Sasanian Empire and the Byzantine Empire, as well as the country of Tokharistan.
The statues were blown up and destroyed in March 2001 by the Taliban, on orders from leader Mullah Mohammed Omar, after the Taliban government declared that they were idols. International and local opinion strongly condemned the destruction of the Buddhas. Some Taliban sources credited Omar's decision to blow up the Buddha statues to the growing influence of Osama bin Laden.