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π Radiotrophic fungus
Radiotrophic fungi are fungi which appear to perform radiosynthesis, that is, to use the pigment melanin to convert gamma radiation into chemical energy for growth. This proposed mechanism may be similar to anabolic pathways for the synthesis of reduced organic carbon (e.g., carbohydrates) in phototrophic organisms, which convert photons from visible light with pigments such as chlorophyll whose energy is then used in photolysis of water to generate usable chemical energy (as ATP) in photophosphorylation or photosynthesis. However, whether melanin-containing fungi employ a similar multi-step pathway as photosynthesis, or some chemosynthesis pathways, is unknown.
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- "Radiotrophic fungus" | 2019-07-03 | 262 Upvotes 63 Comments
π Frank Rosenblatt
Frank Rosenblatt (July 11, 1928Β β July 11, 1971) was an American psychologist notable in the field of artificial intelligence. He is sometimes called the father of deep learning for his pioneering work on neural networks.
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- "Frank Rosenblatt" | 2023-04-07 | 70 Upvotes 39 Comments
π Wolf 359
Wolf 359 is a red dwarf star located in the constellation Leo, near the ecliptic. At a distance of approximately 7.9 light years from Earth, it has an apparent magnitude of 13.54 and can only be seen with a large telescope. Wolf 359 is one of the nearest stars to the Sun; only the Alpha Centauri system (including Proxima Centauri), Barnard's Star and the brown dwarfs Luhman 16 and WISE 0855β0714 are known to be closer. Its proximity to Earth has led to its mention in several works of fiction.
Wolf 359 is one of the faintest and lowest-mass stars known. At the light-emitting layer called the photosphere, it has a temperature of about 2,800Β K, which is low enough for chemical compounds to form and survive. The absorption lines of compounds such as water and titanium(II) oxide have been observed in the spectrum. The surface has a magnetic field that is stronger than the average magnetic field on the Sun. As a result of magnetic activity caused by convection, Wolf 359 is a flare star that can undergo sudden increases in luminosity for several minutes. These flares emit strong bursts of X-ray and gamma ray radiation that have been observed by space telescopes. Wolf 359 is a relatively young star with an age of less than a billion years. Two planetary companions are suspected but as yet no debris disks have been unmasked.
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- "Wolf 359" | 2019-12-23 | 84 Upvotes 49 Comments
π Crookes Radiometer
The Crookes radiometer (also known as a light mill) consists of an airtight glass bulb containing a partial vacuum, with a set of vanes which are mounted on a spindle inside. The vanes rotate when exposed to light, with faster rotation for more intense light, providing a quantitative measurement of electromagnetic radiation intensity.
The reason for the rotation was a cause of much scientific debate in the ten years following the invention of the device, but in 1879 the currently accepted explanation for the rotation was published. Today the device is mainly used in physics education as a demonstration of a heat engine run by light energy.
It was invented in 1873 by the chemist Sir William Crookes as the by-product of some chemical research. In the course of very accurate quantitative chemical work, he was weighing samples in a partially evacuated chamber to reduce the effect of air currents, and noticed the weighings were disturbed when sunlight shone on the balance. Investigating this effect, he created the device named after him.
It is still manufactured and sold as an educational aid or for curiosity.
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- "Crookes Radiometer" | 2024-03-20 | 75 Upvotes 21 Comments
π Milk Watcher
A milk watcher, milk saver, pot watcher, pot minder, milk guard, or boil over preventer is a cooking utensil placed at the bottom of a pot to prevent the foaming boil-over of liquids by collecting small bubbles of steam into one large bubble.
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- "Milk Watcher" | 2024-05-26 | 150 Upvotes 91 Comments
π List of countries by life expectancy
The article documents lists of countries by average life expectancy at birth by various sources of estimates.
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- "List of countries by life expectancy" | 2012-12-14 | 14 Upvotes 8 Comments
π Senet: board game from predynastic and ancient Egypt
Senet (or senat) is a board game from ancient Egypt, whose original rules are the subject of conjecture. The oldest hieroglyph resembling a senet game dates to around 3100 BC. The full name of the game in Egyptian is thought to have been zn.t n.t αΈ₯Λb, meaning the "game of passing".
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- "Senet" | 2021-07-19 | 293 Upvotes 119 Comments
- "Senet: board game from predynastic and ancient Egypt" | 2016-02-14 | 33 Upvotes 5 Comments
π Economy of the Socialist Federal Republic of Yugoslavia
Despite common origins, the economy of the Socialist Federal Republic of Yugoslavia (SFRY) was significantly different from the economies of the Soviet Union and other Eastern European socialist states, especially after the Yugoslav-Soviet break-up in 1948. The occupation and liberation struggle in World War II left Yugoslavia's infrastructure devastated. Even the most developed parts of the country were largely rural and the little industry of the country was largely damaged or destroyed.
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- "Economy of the Socialist Federal Republic of Yugoslavia" | 2013-06-07 | 21 Upvotes 3 Comments
π Enigma Variations
Edward Elgar composed his Variations on an Original Theme, Op. 36, popularly known as the Enigma Variations, between October 1898 and February 1899. It is an orchestral work comprising fourteen variations on an original theme.
Elgar dedicated the work "to my friends pictured within", each variation being a musical sketch of one of his circle of close acquaintances (see musical cryptogram). Those portrayed include Elgar's wife Alice, his friend and publisher Augustus J. Jaeger and Elgar himself. In a programme note for a performance in 1911 Elgar wrote:
This work, commenced in a spirit of humour & continued in deep seriousness, contains sketches of the composer's friends. It may be understood that these personages comment or reflect on the original theme & each one attempts a solution of the Enigma, for so the theme is called. The sketches are not 'portraits' but each variation contains a distinct idea founded on some particular personality or perhaps on some incident known only to two people. This is the basis of the composition, but the work may be listened to as a 'piece of music' apart from any extraneous consideration.
In naming his theme "Enigma", Elgar posed a challenge which has generated much speculation but has never been conclusively answered. The Enigma is widely believed to involve a hidden melody.
After its 1899 London premiere the Variations achieved immediate popularity and established Elgar's international reputation.
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- "Enigma Variations" | 2022-11-04 | 45 Upvotes 10 Comments
π Proofs from the Book
Proofs from THE BOOK is a book of mathematical proofs by Martin Aigner and GΓΌnter M. Ziegler. The book is dedicated to the mathematician Paul ErdΕs, who often referred to "The Book" in which God keeps the most elegant proof of each mathematical theorem. During a lecture in 1985, ErdΕs said, "You don't have to believe in God, but you should believe in The Book."
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- "Proofs from the Book" | 2023-07-21 | 72 Upvotes 8 Comments