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🔗 Electronics

In signal processing, the Nyquist frequency (or folding frequency), named after Harry Nyquist, is a characteristic of a sampler, which converts a continuous function or signal into a discrete sequence. For a given sampling rate (samples per second), the Nyquist frequency (cycles per second) is the frequency whose cycle-length (or period) is twice the interval between samples, thus 0.5 cycle/sample. For example, audio CDs have a sampling rate of 44100 samples/second. At 0.5 cycle/sample, the corresponding Nyquist frequency is 22050 cycles/second (Hz). Conversely, the Nyquist rate for sampling a 22050 Hz signal is 44100 samples/second.

When the highest frequency (bandwidth) of a signal is less than the Nyquist frequency of the sampler, the resulting discrete-time sequence is said to be free of the distortion known as aliasing, and the corresponding sample rate is said to be above the Nyquist rate for that particular signal.

In a typical application of sampling, one first chooses the highest frequency to be preserved and recreated, based on the expected content (voice, music, etc.) and desired fidelity. Then one inserts an anti-aliasing filter ahead of the sampler. Its job is to attenuate the frequencies above that limit. Finally, based on the characteristics of the filter, one chooses a sample rate (and corresponding Nyquist frequency) that will provide an acceptably small amount of aliasing. In applications where the sample rate is pre-determined (such as the CD rate), the filter is chosen based on the Nyquist frequency, rather than vice versa.

🔗 Trains 🔗 Trains/UK Railways 🔗 Trains/Locomotives

LNER Peppercorn Class A1 No. 60163 Tornado is a 4-6-2 steam locomotive completed in 2008 to an original design by Arthur Peppercorn. It is the first new build British mainline steam locomotive since 1960, and the only Peppercorn Class A1 in existence after the original batch were scrapped. In 2017, Tornado became the first steam locomotive to officially reach 100 mph (160 km/h) on British tracks in over 50 years.

After the project was founded by the A1 Steam Locomotive Trust in 1990, construction of Tornado began in 1994 and mostly took place at Darlington Works, with other components manufactured elsewhere. The project was financed through fundraising initiatives, public donations, sponsorship deals, and hiring out Tornado itself for special services. The locomotive was granted its mainline certificate in January 2009, having been designed in compliance with modern safety and certification standards. Tornado has worked on heritage and mainline trains across Britain since 2008. In 2022, it was withdrawn for overhaul.

🔗 Politics

In popular discourse, the horseshoe theory asserts that the far-left and the far-right, rather than being at opposite and opposing ends of a linear continuum of the political spectrum, closely resemble each other, analogous to the way that the opposite ends of a horseshoe are close together. The theory is attributed to the French philosopher and writer of fiction and poetry Jean-Pierre Faye in his 2002 book Le Siècle des idéologies ("The Century of Ideologies").

Several political scientists, psychologists, and sociologists have criticized the horseshoe theory. Proponents point to a number of perceived similarities between extremes and allege that both have a tendency to support authoritarianism or totalitarianism; this does not appear to be supported by scholars in the field of political science, and the few instances of peer-reviewed research on the subject are scarce. Existing studies and comprehensive reviews often find only limited support and only under certain conditions; they generally contradict the theory's central premises.

🔗 Psychology

A cognitive distortion is an exaggerated or irrational thought pattern involved in the onset and perpetuation of psychopathological states, especially those more influenced by psychosocial factors, such as depression and anxiety. Psychiatrist Aaron T. Beck laid the groundwork for the study of these distortions, and his student David D. Burns continued research on the topic. Burns, in Feeling Good the new Mood Therapy , described personal and professional anecdotes related to cognitive distortions and their elimination.

Cognitive distortions are thoughts that cause individuals to perceive reality inaccurately. According to the cognitive model of Beck, a negative outlook on reality, sometimes called negative schemas (or schemata), is a factor in symptoms of emotional dysfunction and poorer subjective well-being. Specifically, negative thinking patterns reinforce negative emotions and thoughts. During difficult circumstances, these distorted thoughts can contribute to an overall negative outlook on the world and a depressive or anxious mental state.

Challenging and changing cognitive distortions is a key element of cognitive behavioral therapy (CBT).

🔗 Computing 🔗 Animation

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.

🔗 Polynesia 🔗 Anthropology 🔗 Norway 🔗 Archaeology 🔗 South America 🔗 Sailing

The Kon-Tiki expedition was a 1947 journey by raft across the Pacific Ocean from South America to the Polynesian islands, led by Norwegian explorer and writer Thor Heyerdahl. The raft was named Kon-Tiki after the Inca god Viracocha, for whom "Kon-Tiki" was said to be an old name. Kon-Tiki is also the name of Heyerdahl's book, the Academy Award-winning 1950 documentary film chronicling his adventures, and the 2012 dramatized feature film nominated for the Academy Award for Best Foreign Language Film.

Heyerdahl believed that people from South America could have reached Polynesia during pre-Columbian times. His aim in mounting the Kon-Tiki expedition was to show, by using only the materials and technologies available to those people at the time, that there were no technical reasons to prevent them from having done so. Although the expedition carried some modern equipment, such as a radio, watches, charts, sextant, and metal knives, Heyerdahl argued they were incidental to the purpose of proving that the raft itself could make the journey.

Heyerdahl's hypothesis of a South American origin of the Polynesian peoples, as well as his "drift voyaging" hypothesis, is generally rejected by scientists today. Archaeological, linguistic, cultural, and genetic evidence tends to support a western origin for Polynesians, from Island Southeast Asia, using sophisticated multihull sailing technologies and navigation techniques during the Austronesian expansion. However, there is evidence of some gene flow from South America to Easter Island.

The Kon-Tiki expedition was funded by private loans, along with donations of equipment from the United States Army. Heyerdahl and a small team went to Peru, where, with the help of dockyard facilities provided by the Peruvian authorities, they constructed the raft out of balsa logs and other native materials in an indigenous style as recorded in illustrations by Spanish conquistadores. The trip began on April 28, 1947. Heyerdahl and five companions sailed the raft for 101 days over 6,900 km (4,300 miles) across the Pacific Ocean before smashing into a reef at Raroia in the Tuamotus on August 7, 1947. The crew made successful landfall and all returned safely.

Thor Heyerdahl's book about his experience became a bestseller. It was published in Norwegian in 1948 as The Kon-Tiki Expedition: By Raft Across the South Seas, later reprinted as Kon-Tiki: Across the Pacific in a Raft. It appeared with great success in English in 1950, also in many other languages. A documentary motion picture about the expedition, also called Kon-Tiki, was produced from a write-up and expansion of the crew's filmstrip notes and won an Academy Award in 1951. It was directed by Heyerdahl and edited by Olle Nordemar. The voyage was also chronicled in the documentary TV-series The Kon-Tiki Man: The Life and Adventures of Thor Heyerdahl, directed by Bengt Jonson.

The original Kon-Tiki raft is now on display in the Kon-Tiki Museum at Bygdøy in Oslo.

🔗 United States 🔗 Germany 🔗 Canada 🔗 Food and drink 🔗 Guild of Copy Editors 🔗 Canada/Ontario 🔗 Hawaii

Hawaiian pizza is a pizza topped with tomato sauce, cheese, pineapple, and ham.

Fart lighting also known as pyroflatulence, or flatus ignition is the practice of igniting the gases produced by flatulence. The resulting flame is often of a blue hue hence the act being known colloquially as a "blue angel", "blue dart" or in Australia, a "blue flame". The fact that flatus is flammable and the actual combustion of it through this practice gives rise to much humorous derivation. Other colors of flame such as orange and yellow are possible depending on the mixture of gases formed in the colon.

In 1999 author Jim Dawson observed that fart lighting has been a novelty practice primarily among young men or college students for decades but is discouraged for its potential for causing harm. Such experiments typically occur on camping trips and in same-sex group residences, such as tree-houses, dormitories, or fraternity houses. With the advent of video sharing features online, hundreds of self-produced videos, both documentary as well as spoof, have been posted to sites such as YouTube. The people appearing in the videos are predominantly young teen males. In his book The Curse of the Self: Self-Awareness, Egotism, and the Quality of Human Life author Mark Richard Leary explains how a great deal of unhappiness is due to people's inability to exert control over their thoughts and behavior and that "stupid stunts", including lighting flatulence, were a way to make an impression and be included in group bonding or hazing.

Although there is little scientific discourse on the combustive properties of flatus, there are many anecdotal accounts of flatus ignition and the activity has increasingly found its way into popular culture with references in comic routines, movies, and television; including cartoons. In Electric Don Quixote: The Definitive Story of Frank Zappa author Neil Slaven quotes Frank Zappa for calling fart lighting "The manly art of fart-burning", and another book quotes the musician Kenny Williams for saying that it demonstrates "compression, ignition, combustion and exhaust."

There have been documented cases of flatulence during surgery being inadvertently ignited causing patient injury and the risk of death.

🔗 Medicine 🔗 Psychology 🔗 Linguistics 🔗 Linguistics/Applied Linguistics 🔗 Education

Spaced repetition is an evidence-based learning technique that is usually performed with flashcards. Newly introduced and more difficult flashcards are shown more frequently while older and less difficult flashcards are shown less frequently in order to exploit the psychological spacing effect. The use of spaced repetition has been shown to increase rate of learning.

Although the principle is useful in many contexts, spaced repetition is commonly applied in contexts in which a learner must acquire many items and retain them indefinitely in memory. It is, therefore, well suited for the problem of vocabulary acquisition in the course of second-language learning. A number of spaced repetition software programs have been developed to aid the learning process. Alternative names for spaced repetition include spaced rehearsal, expanding rehearsal, graduated intervals, repetition spacing, repetition scheduling, spaced retrieval and expanded retrieval.

🔗 Video games 🔗 Computing 🔗 Computer graphics

In 3D computer graphics, anisotropic filtering (abbreviated AF) is a method of enhancing the image quality of textures on surfaces of computer graphics that are at oblique viewing angles with respect to the camera where the projection of the texture (not the polygon or other primitive on which it is rendered) appears to be non-orthogonal (thus the origin of the word: "an" for not, "iso" for same, and "tropic" from tropism, relating to direction; anisotropic filtering does not filter the same in every direction).

Like bilinear and trilinear filtering, anisotropic filtering eliminates aliasing effects, but improves on these other techniques by reducing blur and preserving detail at extreme viewing angles.

Anisotropic filtering is relatively intensive (primarily memory bandwidth and to some degree computationally, though the standard space–time tradeoff rules apply) and only became a standard feature of consumer-level graphics cards in the late 1990s. Anisotropic filtering is now common in modern graphics hardware (and video driver software) and is enabled either by users through driver settings or by graphics applications and video games through programming interfaces.