New Articles (Page 24)
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π Beaver-engineered dam in the Czech Republic
In early 2025, beaver activity in the Brdy Protected Landscape Area, Czech Republic, contributed to the restoration of a wetland ecosystem. A family of beavers constructed a series of dams that accomplished environmental goals set by the Czech government, which had delayed its proposed project since 2018 for bureaucratic and financial reasons. The beaver-built dams saved the Czech government approximately US$1.2 million, providing ecological benefits including improved water quality, enhanced biodiversity, and better water retention.
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- "Beaver-engineered dam in the Czech Republic" | 2025-10-20 | 126 Upvotes 61 Comments
π Great horse manure crisis of 1894
The great horse manure crisis of 1894 refers to the idea that the greatest obstacle to urban development at the turn of the century was the difficulty of removing horse manure from the streets. More broadly, it is an analogy for supposedly insuperable extrapolated problems being rendered moot by the introduction of new technologies. The phrase originates from a 2004 article by Stephen Davies entitled "The Great Horse-Manure Crisis of 1894".
The supposed problem of excessive horse-manure collecting in the streets was solved by the proliferation of cars, buses and electrified trams which replaced horses as the means of transportation in big cities. The term great horse manure crisis of 1894 is often used to denote a problem which seems to be impossible to solve because it is being looked at from the wrong direction.
The name refers to a supposed 1894 publication in The Times, which said "In 50 years, every street in London will be buried under nine feet of manure". The reasoning was that more horses are needed to remove the manure, and these horses produce more manure. An urban planning conference in 1898 supposedly broke up before its scheduled end due to a failure to find an answer to this problem. No such statement in the Times, nor conference result, is known, but in 1893 London there was a complaint that horse manure, formerly an economic good that could be sold, had become a disposal problem, an economic bad.
The supposed crisis has since taken on life as a useful analogy.
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- "The Great Horse Manure Crisis of 1894: predictions of 9 feet of manure in cities" | 2025-10-14 | 30 Upvotes 55 Comments
- "Great horse manure crisis of 1894" | 2023-12-16 | 14 Upvotes 5 Comments
π Electromagnetically Induced Acoustic Noise
Electromagnetically induced acoustic noise (and vibration), electromagnetically excited acoustic noise, or more commonly known as coil whine, is audible sound directly produced by materials vibrating under the excitation of electromagnetic forces. Some examples of this noise include the mains hum, hum of transformers, the whine of some rotating electric machines, or the buzz of fluorescent lamps. The hissing of high voltage transmission lines is due to corona discharge, not magnetism.
The phenomenon is also called audible magnetic noise, electromagnetic acoustic noise, lamination vibration or electromagnetically induced acoustic noise, or more rarely, electrical noise, or "coil noise", depending on the application. The term electromagnetic noise is generally avoided as the term is used in the field of electromagnetic compatibility, dealing with radio frequencies. The term electrical noise describes electrical perturbations occurring in electronic circuits, not sound. For the latter use, the terms electromagnetic vibrations or magnetic vibrations, focusing on the structural phenomenon are less ambiguous.
Acoustic noise and vibrations due to electromagnetic forces can be seen as the reciprocal of microphonics, which describes how a mechanical vibration or acoustic noise can induce an undesired electrical perturbation.
Discussed on
- "Electromagnetically Induced Acoustic Noise" | 2025-10-13 | 16 Upvotes 11 Comments
π Kleptoparasitism
Kleptoparasitism (originally spelt clepto-parasitism, meaning "parasitism by theft") is a form of feeding behavior in which one animal β i.e. the kleptoparasite β deliberately takes food from another animal, often via aggressive confrontations. The strategy is evolutionarily stable when stealing is less costly than direct predation, such as when food is scarce or when physically weaker/less assertive victims are abundant and unlikely to fight back.
Many kleptoparasites are arthropods, especially bees and wasps, but including some true flies, dung beetles, bugs and spiders. Cuckoo bees are specialized kleptoparasites which lay their eggs either on the pollen masses made by other bees, or on the insect hosts of parasitoid wasps. They are an instance of Emery's rule, which states that insect social parasites tend to be closely related to their hosts. The behavior also occurs among vertebrates including birds such as skuas, who persistently chase and harass other seabirds until they disgorge their food; and hypercarnivorous mammals such as spotted hyenas and lions, who routinely rob killed prey from each other and other mesopredators such as cheetahs. Other species might also opportunistically indulge in kleptoparasitism, especially when driven by the desperation of hunger and when scavenging isn't an option.
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- "Kleptoparasitism" | 2025-10-12 | 20 Upvotes 4 Comments
π Why Wikipedia cannot claim the earth is not flat
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- "Why Wikipedia cannot claim the Earth is not flat" | 2025-10-12 | 140 Upvotes 129 Comments
- "Why Wikipedia cannot claim the Earth is not flat" | 2022-08-25 | 21 Upvotes 1 Comments
- "Why Wikipedia cannot claim the earth is not flat" | 2017-11-20 | 212 Upvotes 121 Comments
π Hector (Cloud)
Hector is a cumulonimbus thundercloud cluster that forms regularly nearly every afternoon on the Tiwi Islands in the Northern Territory of Australia, from approximately September to March each year. Hector, or sometimes Hector the Convector, is known as one of the world's most consistently large thunderstorms; specifically, a small mesoscale convective system (MCS) or large multicellular thunderstorm. It reaches heights of approximately 20 kilometres (66,000Β ft).
π Deepstaria Enigmatica
Deepstaria enigmatica is a very rarely seen giant jellyfish of the family Ulmaridae first described in 1967 by F. S. Russell.
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- "Deepstaria Enigmatica" | 2025-10-11 | 21 Upvotes 2 Comments
π Ortega hypothesis
The Ortega hypothesis holds that average or mediocre scientists contribute substantially to the advancement of science. According to this hypothesis, scientific progress occurs mainly by the accumulation of a mass of modest, narrowly specialized intellectual contributions. On this view, major breakthroughs draw heavily upon a large body of minor and little-known work, without which the major advances could not happen.
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- "Ortega hypothesis" | 2025-10-08 | 225 Upvotes 117 Comments
π Knuth's Algorithm X
Algorithm X is an algorithm for solving the exact cover problem. It is a straightforward recursive, nondeterministic, depth-first, backtracking algorithm used by Donald Knuth to demonstrate an efficient implementation called DLX, which uses the dancing links technique.
π Jeffrey Hudson the Court Dwarf of the English Queen Henrietta Maria of France
Jeffrey Hudson (1619 β c.β1682) was a court dwarf of the English queen Henrietta Maria of France. He was famous as the "Queen's dwarf" and "Lord Minimus" and was considered one of the "wonders of the age" because of his extreme but well-proportioned smallness. He fought with the Royalists in the English Civil War and fled with the Queen to France but was expelled from her court when he killed a man in a duel. He was captured by Barbary pirates and spent 25 years enslaved in North Africa before being ransomed back to England.
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- "Jeffrey Hudson the Court Dwarf of the English Queen Henrietta Maria of France" | 2025-10-07 | 49 Upvotes 18 Comments