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🔗 Computer science

In information theory, linguistics and computer science, the Levenshtein distance is a string metric for measuring the difference between two sequences. Informally, the Levenshtein distance between two words is the minimum number of single-character edits (insertions, deletions or substitutions) required to change one word into the other. It is named after the Soviet mathematician Vladimir Levenshtein, who considered this distance in 1965.

Levenshtein distance may also be referred to as edit distance, although that term may also denote a larger family of distance metrics known collectively as edit distance. It is closely related to pairwise string alignments.

🔗 Biography 🔗 Physics 🔗 Philosophy 🔗 Biography/science and academia 🔗 Philosophy/Philosophy of science 🔗 Philosophy/Contemporary philosophy 🔗 History of Science 🔗 Philosophy/Philosophers 🔗 Physics/Biographies 🔗 Ireland 🔗 University of Oxford 🔗 University of Oxford/University of Oxford (colleges)

Erwin Rudolf Josef Alexander Schrödinger (UK: , US: ; German: [ˈɛɐ̯vɪn ˈʃʁøːdɪŋɐ]; 12 August 1887 – 4 January 1961), sometimes written as Schroedinger or Schrodinger, was a Nobel Prize–winning Austrian and naturalized Irish physicist who developed fundamental results in quantum theory. In particular, he is recognized for postulating the Schrödinger equation, an equation that provides a way to calculate the wave function of a system and how it changes dynamically in time. He coined the term "quantum entanglement", and was the earliest to discuss it, doing so in 1932.

In addition, he wrote many works on various aspects of physics: statistical mechanics and thermodynamics, physics of dielectrics, colour theory, electrodynamics, general relativity, and cosmology, and he made several attempts to construct a unified field theory. In his book What Is Life? Schrödinger addressed the problems of genetics, looking at the phenomenon of life from the point of view of physics. He also paid great attention to the philosophical aspects of science, ancient, and oriental philosophical concepts, ethics, and religion. He also wrote on philosophy and theoretical biology. In popular culture, he is best known for his "Schrödinger's cat" thought experiment.

Spending most of his life as an academic with positions at various universities, Schrödinger, along with Paul Dirac, won the Nobel Prize in Physics in 1933 for his work on quantum mechanics, the same year he left Germany due to his opposition to Nazism. In his personal life, he lived with both his wife and his mistress which may have led to problems causing him to leave his position at Oxford. Subsequently, until 1938, he had a position in Graz, Austria, until the Nazi takeover when he fled, finally finding a long-term arrangement in Dublin where he remained until retirement in 1955. He died in Vienna of tuberculosis when he was 73.

🔗 Biography 🔗 Military history 🔗 Ancient Near East 🔗 Military history/Classical warfare

Piyamaradu (also spelled Piyama-Radu, Piyama Radu, Piyamaradus, Piyamaraduš) was a warlike personage whose name figures prominently in the Hittite archives of the middle and late 13th century BC in western Anatolia. His history is of particular interest because it appears to intertwine with that of the Trojan War. Some scholars assume that his name is cognate to that of King Priam of Troy.

🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation 🔗 Military history/Military science, technology, and theory 🔗 Aviation/aircraft

In aerobatics the Cobra maneuver, also known as just the Cobra, is a dramatic and demanding maneuver in which an airplane flying at a moderate speed suddenly raises the nose momentarily to the vertical position and slightly beyond, before dropping it back to normal, effectively making the plane a full body air brake.

The maneuver relies on the ability of the plane to be able to quickly change alpha which momentarily stalls the plane without overloading the airframe and powerful engine thrust to maintain approximately constant altitude through the entire move. It is an impressive maneuver to demonstrate an aircraft's pitch control authority, high alpha stability and engine-versus-inlet compatibility, as well as the pilot's skill.

Although the maneuver is mainly performed at air shows it has use in close range air combat as a last ditch maneuver to make a pursuing plane overshoot. There is currently no widely spread or readily available evidence of the Cobra being used in real combat, although, there are records of it being used during mockup-dogfights and during border protection.

🔗 China 🔗 Writing systems

Since the second half of the 20th century, inscriptions have been found on pottery in a variety of locations in China, such as Banpo near Xi'an, as well as on bone and bone marrows at Hualouzi, Chang'an County near Xi'an. These simple, often geometric, marks have been frequently compared to some of the earliest known Chinese characters appearing on the oracle bones, and some have taken them to mean that the history of Chinese writing extends back over six millennia. However, only isolated instances of these symbols have been found, and they show no indication of representing speech or of the non-pictorial processes that a writing system requires.

🔗 Volcanoes 🔗 Meteorology

The year 1816 is known as the Year Without a Summer (also the Poverty Year and Eighteen Hundred and Froze To Death) because of severe climate abnormalities that caused average global temperatures to decrease by 0.4–0.7 °C (0.72–1.26 °F). This resulted in major food shortages across the Northern Hemisphere.

Evidence suggests that the anomaly was predominantly a volcanic winter event caused by the massive 1815 eruption of Mount Tambora in April in the Dutch East Indies (now Indonesia). This eruption was the largest eruption in at least 1,300 years (after the hypothesized eruption causing the extreme weather events of 535–536), and perhaps exacerbated by the 1814 eruption of Mayon in the Philippines.

🔗 Palaeontology 🔗 Geology 🔗 Extinction

The Permian–Triassic extinction event, also known as the P–Tr extinction, the P–T extinction, the End-Permian Extinction, and colloquially as the Great Dying, formed the boundary between the Permian and Triassic geologic periods, as well as between the Paleozoic and Mesozoic eras, approximately 252 million years ago. It is the Earth's most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It was the largest known mass extinction of insects. Some 57% of all biological families and 83% of all genera became extinct.

There is evidence for one to three distinct pulses, or phases, of extinction. Potential causes for those pulses include one or more large meteor impact events, massive volcanic eruptions (such as the Siberian Traps), and climate change brought on by large releases of underwater methane or methane-producing microbes.

The speed of the recovery from the extinction is disputed. Some scientists estimate that it took 10 million years (until the Middle Triassic), due both to the severity of the extinction and because grim conditions returned periodically for another 5 million years. However, studies in Bear Lake County, near Paris, Idaho, showed a relatively quick rebound in a localized Early Triassic marine ecosystem, taking around 2 million years to recover, suggesting that the impact of the extinction may have been felt less severely in some areas than others.

🔗 Internet culture 🔗 Cats

Longcat (2002 – 20 September 2020) was a Japanese domestic cat that became the subject of an Internet meme due to her length. Longcat, whose real name was "Shiroi", was born in 2002. An image depicting her being held with "outstretched paws" became popular on Japanese imageboard Futaba Channel, where it was nicknamed "Nobiko" ("Stretch" in Japanese) some time around 2005 or 2006. She was reportedly 65 centimetres (26 in) "from head to toe".

Subsequently, the meme spread to English-language websites, primarily 4chan's /b/, where it was edited into various images, and even had a song written about it. A backstory was invented for the cat, involving a world-ending battle called "Catnarok" with a nemesis named "Tacgnol" (resembling Longcat with the colors inverted).

The virtual community and message board Subeta, which made available a number of pixel art virtual accessories for user avatars, briefly introduced a "Longcat scarf" in 2007; this prompted "a legion of internet users to attack Subeta", primarily in the form of a DDoS campaign involving "all of the chans", until the Longcat item was removed later in the month. A Pokémon design released in 2019, the "Gigantamax Meowth", was compared by some commentators to Longcat.

In a 2019 interview, Longcat's owner said that the cat was "originally rescued after being discovered on the street in 2002", and at the time was thin with gray hair; as she grew older, she became white and fluffy. The cat was deaf. In 2019, Longcat's owner said that, at the age of 17, the cat no longer "climbed to high places" but was "relaxing and living her life".

In September 2020, after a period of ill health, Longcat was taken to the hospital, and died at the age of 18.

🔗 Books 🔗 Mongols

The Tartar Relation (Latin: Hystoria Tartarorum, "History of the Tartars") is an ethnographic report on the Mongol Empire composed by a certain C. de Bridia in Latin in 1247. It is one of the most detailed accounts of the history and customs of the Mongols to appear in Europe around that time.

🔗 Computing 🔗 Computer Security 🔗 Computer Security/Computing 🔗 Computing/Software

In information security and programming, a buffer overflow, or buffer overrun, is an anomaly where a program, while writing data to a buffer, overruns the buffer's boundary and overwrites adjacent memory locations.

Buffers are areas of memory set aside to hold data, often while moving it from one section of a program to another, or between programs. Buffer overflows can often be triggered by malformed inputs; if one assumes all inputs will be smaller than a certain size and the buffer is created to be that size, then an anomalous transaction that produces more data could cause it to write past the end of the buffer. If this overwrites adjacent data or executable code, this may result in erratic program behavior, including memory access errors, incorrect results, and crashes.

Exploiting the behavior of a buffer overflow is a well-known security exploit. On many systems, the memory layout of a program, or the system as a whole, is well defined. By sending in data designed to cause a buffer overflow, it is possible to write into areas known to hold executable code and replace it with malicious code, or to selectively overwrite data pertaining to the program's state, therefore causing behavior that was not intended by the original programmer. Buffers are widespread in operating system (OS) code, so it is possible to make attacks that perform privilege escalation and gain unlimited access to the computer's resources. The famed Morris worm in 1988 used this as one of its attack techniques.

Programming languages commonly associated with buffer overflows include C and C++, which provide no built-in protection against accessing or overwriting data in any part of memory and do not automatically check that data written to an array (the built-in buffer type) is within the boundaries of that array. Bounds checking can prevent buffer overflows, but requires additional code and processing time. Modern operating systems use a variety of techniques to combat malicious buffer overflows, notably by randomizing the layout of memory, or deliberately leaving space between buffers and looking for actions that write into those areas ("canaries").