Random Articles (Page 26)
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π Pourquoi-Pas (1908)
Pourquoi Pas? IV (English: Why Not? IV) was the fourth ship built for Jean-Baptiste Charcot, which completed the second Charcot expedition of the Antarctic regions from 1908 to 1910. Charcot died aboard when the ship was wrecked on 16 September 1936, off the coast of Iceland. Of the forty men on board, only one survived.
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- "Pourquoi-Pas (1908)" | 2019-09-08 | 38 Upvotes 10 Comments
π James Lovelock Has Died
James Ephraim Lovelock (26 July 1919 β 26 July 2022) was a British independent scientist, environmentalist and futurist. He was best known for proposing the Gaia hypothesis, which postulates that the Earth functions as a self-regulating system.
With a PhD in medicine, Lovelock began his career performing cryopreservation experiments on rodents, including successfully thawing frozen specimens. His methods were influential in the theories of cryonics (the cryopreservation of humans). He invented the electron capture detector, and using it, became the first to detect the widespread presence of chlorofluorocarbons in the atmosphere. While designing scientific instruments for NASA, he developed the Gaia hypothesis.
In the 2000s, he proposed a method of climate engineering to restore carbon dioxideβconsuming algae. He was an outspoken member of Environmentalists for Nuclear, asserting that fossil fuel interests have been behind opposition to nuclear energy, citing the effects of carbon dioxide as being harmful to the environment, and warning of global warming due to the greenhouse effect. He authored several environmental science books based upon the Gaia hypothesis from the late 1970s.
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- "James Lovelock Has Died" | 2022-07-27 | 100 Upvotes 19 Comments
π Chaitin's Constant
In the computer science subfield of algorithmic information theory, a Chaitin constant (Chaitin omega number) or halting probability is a real number that, informally speaking, represents the probability that a randomly constructed program will halt. These numbers are formed from a construction due to Gregory Chaitin.
Although there are infinitely many halting probabilities, one for each method of encoding programs, it is common to use the letter Ξ© to refer to them as if there were only one. Because Ξ© depends on the program encoding used, it is sometimes called Chaitin's construction instead of Chaitin's constant when not referring to any specific encoding.
Each halting probability is a normal and transcendental real number that is not computable, which means that there is no algorithm to compute its digits. Indeed, each halting probability is Martin-LΓΆf random, meaning there is not even any algorithm which can reliably guess its digits.
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- "Chaitin's Constant" | 2020-01-20 | 81 Upvotes 38 Comments
π Corpus Clock (Grasshopper Clock)
The Corpus Clock, also known as the Grasshopper clock, is a large sculptural clock at street level on the outside of the Taylor Library at Corpus Christi College, Cambridge University, in the United Kingdom, at the junction of Bene't Street and Trumpington Street, looking out over King's Parade. It was conceived and funded by John C. Taylor, an old member of the college.
It was officially unveiled to the public on 19 September 2008 by Cambridge physicist Stephen Hawking. The clock was named one of Time's Best Inventions of 2008.
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- "Corpus Clock (Grasshopper Clock)" | 2021-06-02 | 112 Upvotes 32 Comments
π Circle-Ellipse Problem
The circleβellipse problem in software development (sometimes called the squareβrectangle problem) illustrates several pitfalls which can arise when using subtype polymorphism in object modelling. The issues are most commonly encountered when using object-oriented programming (OOP). By definition, this problem is a violation of the Liskov substitution principle, one of the SOLID principles.
The problem concerns which subtyping or inheritance relationship should exist between classes which represent circles and ellipses (or, similarly, squares and rectangles). More generally, the problem illustrates the difficulties which can occur when a base class contains methods which mutate an object in a manner which may invalidate a (stronger) invariant found in a derived class, causing the Liskov substitution principle to be violated.
The existence of the circleβellipse problem is sometimes used to criticize object-oriented programming. It may also imply that hierarchical taxonomies are difficult to make universal, implying that situational classification systems may be more practical.
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- "Circle-Ellipse Problem" | 2011-04-17 | 21 Upvotes 20 Comments
π The Pizza Meter
The Pizza Meter refers to sudden increases of pizza orders from U.S. government offices, such as the White House and The Pentagon, before large events such as the Iraqi invasion of Kuwait, the Panama Invasion, and the Grenada invasion.
On the night of August 1, 1990, the night before the Iraqi invasion of Kuwait, military personnel at The Pentagon came together to discuss issues in the Middle East. According to Frank Meeks, the owner of Washington, D.C.'s Domino's Pizza franchise of 45 restaurants, the CIA ordered a record-breaking 21 pizzas from Domino's that night. Between January 7 to January 16, 1991, the number of pizza deliveries to the Pentagon past 10 p.m reached 101, with another 55 pizzas delivered to the White House on January 16 between 10 p.m. and 2 a.m.
Meeks tied the influx of pizza orders from the Pentagon, White House, and the CIA to oncoming major announcements from the White House, publicizing his observations. Consequently, the public nicknamed the event "The Pizza Meter". Shortly after Meeks' comments were released, government offices no longer ordered from Domino's branches in Washington, opting to buy pizza at separate times or at different pizza joints.
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- "The Pizza Meter" | 2024-03-24 | 18 Upvotes 2 Comments
π Gombe Chimpanzee War
The Gombe Chimpanzee War was a violent conflict between two communities of chimpanzees in Gombe Stream National Park in Tanzania lasting from 1974 to 1978. The two groups were once unified in the Kasakela community. By 1974, researcher Jane Goodall noticed the community splintering. Over a span of eight months, a large party of chimpanzees separated themselves into the southern area of Kasakela and were renamed the Kahama community. The separatists consisted of six adult males, three adult females and their young. The Kasakela was left with eight adult males, twelve adult females and their young.
During the four-year conflict, all males of the Kahama community were killed, effectively disbanding the community. The victorious Kasakela then expanded into further territory but were later repelled by another community of chimpanzees.
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- "Gombe Chimpanzee War" | 2019-09-09 | 138 Upvotes 37 Comments
- "The Gombe Chimpanzee War" | 2014-10-19 | 134 Upvotes 30 Comments
π Elephant intelligence
Elephant cognition is the study of animal cognition as present in elephants. Most contemporary ethologists view the elephant as one of the world's most intelligent animals. With a mass of just over 11Β lb (5Β kg), an elephant's brain has more mass than that of any other land animal, and although the largest whales have body masses twenty times those of a typical elephant, a whale's brain is barely twice the mass of an elephant's brain. In addition, elephants have a total of 300 billion neurons. Elephant brains are similar to humans' and many other mammals' in terms of general connectivity and functional areas, with several unique structural differences. The elephant cortex has as many neurons as a human brain, suggesting convergent evolution.
Elephants manifest a wide variety of behaviors, including those associated with grief, learning, mimicry, play, altruism, use of tools, compassion, cooperation, self-awareness, memory, and communication. Further, evidence suggests elephants may understand pointing: the ability to nonverbally communicate an object by extending a finger, or equivalent. It is thought they are equal with cetaceans and primates in this regard. Due to such claims of high intelligence and due to strong family ties of elephants, some researchers argue it is morally wrong for humans to cull them. Aristotle described the elephant as "the animal that surpasses all others in wit and mind."
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- "Elephant intelligence" | 2008-03-05 | 32 Upvotes 10 Comments
π Beflix (Bell Labs Flicks)
BEFLIX is the name of the first embedded domain-specific language for computer animation, invented by Ken Knowlton at Bell Labs in 1963. The name derives from a combination of Bell Flicks. Ken Knowlton used BEFLIX to create animated films for educational and engineering purposes. He also collaborated with the artist Stan Vanderbeek at Bell Labs to create a series of computer-animated films called Poemfields between 1966 and 1969.
BEFLIX was developed on the IBM 7090 mainframe computer using a Stromberg-Carlson SC4020 microfilm recorder for output. The programming environment targeted by BEFLIX consisted of a FORTRAN II implementation with FORTRAN II Assembly Program (FAP) macros. The first version of BEFLIX was implemented through the FAP macro facility. A later version targeting FORTRAN IV resembled a more traditional subroutine library and lost some of the unique flavor to the language.
Pixels are produced by writing characters to the screen of the microfilm recorder with a defocused electron beam. The SC4020 used a charactron tube to expose microfilm. In BEFLIX, the electron beam is defocused to draw pixels as blurred character shapes. Characters are selected to create a range of grayscale values for pixels. The microfilm recorder is not connected directly to the 7090, but communicates through magnetic tape. BEFLIX writes the magnetic tape output on the 7090 and the film recorder reads the tape to create the film output. BEFLIX also supports a preview mode where selected frames of the output are written to the line printer.
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- "Beflix (Bell Labs Flicks)" | 2024-10-18 | 16 Upvotes 5 Comments
π Up to date list of departures & closures at Sun
The acquisition of Sun Microsystems by Oracle Corporation was completed on January 27, 2010. Significantly, Oracle, previously only a software vendor, now owned both hardware and software product lines from Sun (e.g. SPARC Enterprise and Java, respectively).
A major issue of the purchase was that Sun was a major competitor to Oracle, raising many concerns among antitrust regulators, open source advocates, customers, and employees. The EU Commission delayed the acquisition for several months over concerns of Oracle's plans for MySQL, Sun's competitor to the Oracle Database. The commission finally approved the takeover, apparently pressured by the United States to do so, according to a WikiLeaks cable released in September 2011.
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- "Up to date list of departures & closures at Sun" | 2010-03-13 | 12 Upvotes 3 Comments