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π Bioluminescence
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria, and terrestrial arthropods such as fireflies. In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; in others, it is autogenic, produced by the animals themselves.
In a general sense, the principal chemical reaction in bioluminescence involves a light-emitting molecule and an enzyme, generally called luciferin and luciferase, respectively. Because these are generic names, luciferins and luciferases are often distinguished by the species or group, e.g. firefly luciferin. In all characterized cases, the enzyme catalyzes the oxidation of the luciferin.
In some species, the luciferase requires other cofactors, such as calcium or magnesium ions, and sometimes also the energy-carrying molecule adenosine triphosphate (ATP). In evolution, luciferins vary little: one in particular, coelenterazine, is found in 11 different animal phyla, though in some of these, the animals obtain it through their diet. Conversely, luciferases vary widely between different species, which is evidence that bioluminescence has arisen over 40 times in evolutionary history.
Both Aristotle and Pliny the Elder mentioned that damp wood sometimes gives off a glow. Many centuries later Robert Boyle showed that oxygen was involved in the process, in both wood and glowworms. It was not until the late nineteenth century that bioluminescence was properly investigated. The phenomenon is widely distributed among animal groups, especially in marine environments. On land it occurs in fungi, bacteria and some groups of invertebrates, including insects.
The uses of bioluminescence by animals include counterillumination camouflage, mimicry of other animals, for example to lure prey, and signaling to other individuals of the same species, such as to attract mates. In the laboratory, luciferase-based systems are used in genetic engineering and biomedical research. Researchers are also investigating the possibility of using bioluminescent systems for street and decorative lighting, and a bioluminescent plant has been created.
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- "Bioluminescence" | 2022-06-12 | 13 Upvotes 8 Comments
π Polynesian Voyaging Society
The Polynesian Voyaging Society (PVS) is a non-profit research and educational corporation based in Honolulu, HawaiΚ»i. PVS was established to research and perpetuate traditional Polynesian voyaging methods. Using replicas of traditional double-hulled canoes, PVS undertakes voyages throughout Polynesia navigating without modern instruments.
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- "Polynesian Voyaging Society" | 2019-06-07 | 38 Upvotes 6 Comments
π Moravec's Paradox
Moravec's paradox is the observation by artificial intelligence and robotics researchers that, contrary to traditional assumptions, reasoning (which is high-level in humans) requires very little computation, but sensorimotor skills (comparatively low-level in humans) require enormous computational resources. The principle was articulated by Hans Moravec, Rodney Brooks, Marvin Minsky and others in the 1980s. As Moravec writes, "it is comparatively easy to make computers exhibit adult level performance on intelligence tests or playing checkers, and difficult or impossible to give them the skills of a one-year-old when it comes to perception and mobility".
Similarly, Minsky emphasized that the most difficult human skills to reverse engineer are those that are unconscious. "In general, we're least aware of what our minds do best", he wrote, and added "we're more aware of simple processes that don't work well than of complex ones that work flawlessly".
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- "Moravec's Paradox" | 2023-06-10 | 13 Upvotes 4 Comments
- "Moravec's Paradox" | 2019-08-15 | 155 Upvotes 87 Comments
- "Moravec's paradox" | 2018-04-21 | 30 Upvotes 6 Comments
- "Moravec's paradox" | 2016-02-06 | 30 Upvotes 4 Comments
- "Moravec's paradox" | 2012-12-14 | 188 Upvotes 43 Comments
π Banana equivalent dose
Banana equivalent dose (BED) is an informal measurement of ionizing radiation exposure, intended as a general educational example to compare a dose of radioactivity to the dose one is exposed to by eating one average-sized banana. Bananas contain naturally occurring radioactive isotopes, particularly potassium-40 (40K), one of several naturally-occurring isotopes of potassium. One BED is often correlated to 10β7 sievert (0.1 ΞΌSv); however, in practice, this dose is not cumulative, as the principal radioactive component is excreted to maintain metabolic equilibrium. The BED is only meant to inform the public about the existence of very low levels of natural radioactivity within a natural food and is not a formally adopted dose measurement.
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- "Banana Equivalent Dose" | 2023-05-02 | 84 Upvotes 62 Comments
- "Banana equivalent dose" | 2010-06-14 | 470 Upvotes 84 Comments
π Illusory Superiority
In the field of social psychology, illusory superiority is a condition of cognitive bias wherein a person overestimates their own qualities and abilities, in relation to the same qualities and abilities of other people. Illusory superiority is one of many positive illusions, relating to the self, that are evident in the study of intelligence, the effective performance of tasks and tests, and the possession of desirable personal characteristics and personality traits. Overestimation of abilities compared to an objective measure is known as the overconfidence effect.
The term illusory superiority was first used by the researchers Van Yperen and Buunk, in 1991. The phenomenon is also known as the above-average effect, the superiority bias, the leniency error, the sense of relative superiority, the primus inter pares effect, and the Lake Wobegon effect, named after the fictional town where all the children are above average. The Dunning-Kruger effect is a form of illusory superiority shown by people on a task where their level of skill is low.
A vast majority of the literature on illusory superiority originates from studies on participants in the United States. However, research that only investigates the effects in one specific population is severely limited as this may not be a true representation of human psychology. More recent research investigating self-esteem in other countries suggests that illusory superiority depends on culture. Some studies indicate that East Asians tend to underestimate their own abilities in order to improve themselves and get along with others.
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- "Illusory Superiority" | 2023-07-19 | 24 Upvotes 48 Comments
π The Theory of American Decline
American decline is a term used by various analysts to describe the diminishing power of the United States geopolitically, militarily, financially, economically, socially, and in health and the environment. There has been a debate between declinists, those who believe America is in decline, and exceptionalists, those who feel America is immortal.
Some analysts say that the U.S. was in decline long before Donald Trump ran for presidency; becoming the first presidential candidate to promote the idea that the U.S. was in decline. While others suggest the decline either stems from or has accelerated with Trump's foreign policy and the "countryβs ongoing withdrawal from the global arena." According to Noam Chomsky, America's decline started at the end of WWII, dismissing the "remarkable rhetoric of the several years of triumphalism in the 1990s" as "mostly self-delusion".
Gallup's pollsters recently reported that worldwide approval of U.S. leadership has plunged from 48% in 2016 to a record low of 30% in 2018, in part due to the increasingly isolationist stances of Donald Trump. This drop places the U.S. a notch below China's 31% and leaving Germany as the most popular power with an approval of 41%. Michael Hudson describes financial pillar as paramount, resulting from bank-created money with compound interest and the inbuilt refusal to forgive debts as the fatal flaw.
China's challenging the U.S. for global predominance constitutes the core issue in the debate over the American decline.
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- "The Theory of American Decline" | 2020-06-10 | 32 Upvotes 5 Comments
π Ferrite Bead
A ferrite bead (also known as a ferrite block, ferrite core, ferrite ring, EMI filter, or ferrite choke) is a type of choke that suppresses high-frequency electronic noise in electronic circuits.
Ferrite beads employ high-frequency current dissipation in a ferrite ceramic to build high-frequency noise suppression devices.
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- "Ferrite Bead" | 2023-05-18 | 25 Upvotes 12 Comments
π Intellipedia (U.S. intelligence agencies' internal wiki)
Intellipedia is an online system for collaborative data sharing used by the United States Intelligence Community (IC). It was established as a pilot project in late 2005 and formally announced in April 2006. Intellipedia consists of three wikis running on the separate JWICS (Intellipedia-TS), SIPRNet (Intellipedia-S), and DNI-U (Intellipedia-U) networks. The levels of classification allowed for information on the three wikis are Top Secret Sensitive Compartmented Information (TS SCI), Secret (S), and Sensitive But Unclassified (SBU or FOUO) information, respectively. Each of the wikis is used by individuals with appropriate clearances from the 16 agencies of the US intelligence community and other national-security related organizations, including Combatant Commands and other federal departments. The wikis are not open to the public.
Intellipedia is a project of the Office of the Director of National Intelligence (ODNI) Intelligence Community Enterprise Services (ICES) office headquartered in Fort Meade, Maryland. It includes information on the regions, people, and issues of interest to the communities using its host networks. Intellipedia uses MediaWiki, the same software used by the Wikipedia free-content encyclopedia project. To the contrary of mainstream Wikipedia, its intelligence analogue encourages editing that incorporates personal points of view regardless of rank as it was decided that, "much of the self-corrective knowledge in the Intelligence Community resides in personal points of view," and that, "not all good ideas originate at the top."
The Secret version connected to SIPRNet predominantly serves Department of Defense and the Department of State personnel, many of whom do not use the Top Secret JWICS network on a day-to-day basis. Users on unclassified networks can access Intellipedia from remote terminals outside their workspaces via a VPN, in addition to their normal workstations. Open Source Intelligence (OSINT) users share information on the unclassified Intelink-U wiki.
π 2013 Shahbag Protest
On 5 February 2013, protests began in Shahbag, Bangladesh following demands for capital punishment for Abdul Quader Mollah, who had been sentenced to life imprisonment, and for others convicted of war crimes by the International Crimes Tribunal of Bangladesh. On that day, the International Crimes Tribunal had sentenced Mollah to life in prison after he was convicted on five of six counts of war crimes. Later demands included banning the Bangladesh Jamaat-e-Islami party from politics including election and a boycott of institutions supporting (or affiliated with) the party.
Protesters considered Mollah's sentence too lenient, given his crimes. Bloggers and online activists called for additional protests at Shahbag. Tens of thousands of people joined the demonstration, which gave rise to protests across the country.
A counter-protest, questioning the validity of the tribunal and the protest movement and demanding release of those accused and convicted, was launched by Jamaat-e-Islami as its leaders were the majority of those first identified for trial. The Bangladesh Nationalist Party (BNP) initially expressed its support for Jamaat-e-Islami, a political ally. But, the BNP cautiously welcomed the Shahbag protest, while warning the government not to make political mileage from a movement demanding capital punishment for war criminals.
During the protests, Ahmed Rajib Haider was killed outside his house. On 1 March, five students of North South University were arrested who 'confessed' involvement in Rajib's killing. On 27 February 2013, the tribunal convicted Delwar Hossain Sayeedi of war crimes and sentenced him to death. Jamaat followers protested and there were violent clashes with police. About 60 people were killed in the confrontations; most were Jamaat-Shibir activists, and others were police and civilians.
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- "2013 Shahbag Protest" | 2013-02-09 | 17 Upvotes 7 Comments
π An-225
The Antonov An-225 Mriya (Ukrainian: ΠΠ½ΡΠΎΠ½ΠΎΠ² ΠΠ½-225 ΠΡΡΡ, lit.β'dream' or 'inspiration'; NATO reporting name: Cossack) is a strategic airlift cargo aircraft that was designed by the Antonov Design Bureau in the Ukrainian SSR within the Soviet Union during the 1980s. Originally, this unique aircraft was developed as an enlargement of the Antonov An-124 to transport Buran-class orbiters. After successfully fulfilling its Soviet military missions, it was mothballed for eight years. It was then refurbished and reintroduced into commercial operation with Antonov Airlines, carrying oversized payloads. While a second airframe with a slightly different configuration was partially built, construction was halted more than once due to a lack of funding and interest. This second aircraft was last brought up to 60β70% completion in 2009.
As an over sized aircraft the Antonov An-225 Mriya holds multiple records which include; heaviest aircraft ever built, and largest wingspan of any aircraft in operational service. Other records held by the An-225 are cargo related in terms of weight and length as the Antonov An-225 has the capability to carry up to 640 tonnes (705 short tons). The An-225 attracts a high degree of public interest, so much that it has managed to attain a global following due to its size and its uniqueness. People frequently visit airports to see its scheduled arrivals and departures.
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- "An-225" | 2022-02-27 | 56 Upvotes 32 Comments