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π Canal Defence Light
The Canal Defence Light (CDL) was a British "secret weapon" of the Second World War.
It was based upon the use of a powerful carbon-arc searchlight mounted on a tank. It was intended to be used during night-time attacks, when the light would allow enemy positions to be targeted. A secondary use of the light would be to dazzle and disorient enemy troops, making it harder for them to return fire accurately. The name Canal Defence Light was used to conceal the device's true purpose. For the same reason, in US service they were designated T10 Shop Tractor.
Discussed on
- "Canal Defence Light" | 2015-10-14 | 33 Upvotes 16 Comments
π Sure-thing principle
In decision theory, the sure-thing principle states that a decision maker who would take a certain action if he knew that event E has occurred, and also if he knew that the negation of E has occurred, should also take that same action if he knows nothing about E.
The principle was coined by L.J. Savage:
A businessman contemplates buying a certain piece of property. He considers the outcome of the next presidential election relevant. So, to clarify the matter to himself, he asks whether he would buy if he knew that the Democratic candidate were going to win, and decides that he would. Similarly, he considers whether he would buy if he knew that the Republican candidate were going to win, and again finds that he would. Seeing that he would buy in either event, he decides that he should buy, even though he does not know which event obtains, or will obtain, as we would ordinarily say. It is all too seldom that a decision can be arrived at on the basis of this principle, but except possibly for the assumption of simple ordering, I know of no other extralogical principle governing decisions that finds such ready acceptance.
He formulated the principle as a dominance principle, but it can also be framed probabilistically. Richard Jeffrey and later Judea Pearl showed that Savage's principle is only valid when the probability of the event considered (e.g., the winner of the election) is unaffected by the action (buying the property). Under such conditions, the sure-thing principle is a theorem in the do-calculus (see Bayes networks). Blyth constructed a counterexample to the sure-thing principle using sequential sampling in the context of Simpson's paradox, but this example violates the required action-independence provision.
The principle is closely related to independence of irrelevant alternatives, and equivalent under the axiom of truth (everything the agent knows is true). It is similarly targeted by the Ellsberg and Allais paradoxes, in which actual people's choices seem to violate this principle.
Discussed on
- "Sure-thing principle" | 2018-05-26 | 31 Upvotes 29 Comments
π Ayahuasca
Ayahuasca is a South American (pan-Amazonian) psychoactive brew used both socially and as ceremonial spiritual medicine among the indigenous peoples of the Amazon basin. It is a psychedelic and entheogenic brew commonly made out of the Banisteriopsis caapi vine, the Psychotria viridis shrub or a substitute, and possibly other ingredients. A chemically similar preparation, sometimes called "pharmahuasca", can be prepared using N,N-Dimethyltryptamine (DMT) and a pharmaceutical monoamine oxidase inhibitor (MAOI), such as isocarboxazid. B. caapi contains several alkaloids that act as MAOIs, which are required for DMT to be orally active. Ayahuasca is prepared in a tea that, when consumed, causes an altered state of consciousness or "high", including visual hallucinations and altered perceptions of reality.
The other required ingredient is a plant that contains the primary psychoactive, DMT. This is usually the shrub P. viridis, but Diplopterys cabrerana may be used as a substitute. Other plant ingredients often or occasionally used in the production of ayahuasca include Justicia pectoralis, one of the Brugmansia (especially Brugmansia insignis and Brugmansia versicolor, or a hybrid breed) or Datura species, and mapacho (Nicotiana rustica).
Discussed on
- "Ayahuasca" | 2021-12-05 | 15 Upvotes 8 Comments
π Brandolini's Law
Brandolini's law, also known as the bullshit asymmetry principle, is an internet adage which emphasizes the difficulty of debunking bullshit: "The amount of energy needed to refute bullshit is an order of magnitude bigger than to produce it."
Discussed on
- "Brandolini's law β Amount of energy needed to refute bullshit" | 2025-02-04 | 27 Upvotes 2 Comments
- "Brandolini's Law" | 2024-11-18 | 15 Upvotes 3 Comments
- "Brandolini's Law" | 2023-04-14 | 179 Upvotes 110 Comments
- "Brandolini's Law" | 2021-01-29 | 132 Upvotes 59 Comments
π Differential Power Analysis
In cryptography, power analysis is a form of side channel attack in which the attacker studies the power consumption of a cryptographic hardware device (such as a smart card, tamper-resistant "black box", or integrated circuit). The attack can non-invasively extract cryptographic keys and other secret information from the device.
Simple power analysis (SPA) involves visually interpreting power traces, or graphs of electrical activity over time. Differential power analysis (DPA) is a more advanced form of power analysis, which can allow an attacker to compute the intermediate values within cryptographic computations through statistical analysis of data collected from multiple cryptographic operations. SPA and DPA were introduced to the open cryptology community in 1998 by Paul Kocher, Joshua Jaffe and Benjamin Jun.
π Old Elbe Tunnel
Old Elbe Tunnel or St. Pauli Elbe Tunnel (German: Alter Elbtunnel colloquially or St. Pauli Elbtunnel officially) which opened in 1911, is a pedestrian and vehicle tunnel in Hamburg. The 426 m (1,398 ft) long tunnel was a technical sensation; 24 m (80 ft) beneath the surface, two 6 m (20 ft) diameter tubes connect central Hamburg with the docks and shipyards on the south side of the river Elbe. This was a big improvement for tens of thousands of workers in one of the busiest harbors in the world.
Six large lifts on either side of the tunnel carry pedestrians and vehicles to the bottom. The two tunnels are both still in operation, though due to their limited capacity by today's standards, other bridges and tunnels have been built and taken over most of the traffic.
In 2008 approximately 300,000 cars, 63,000 bicycles, and 700,000 pedestrians used the tunnel. The tunnel is opened 24 hours for pedestrians and bicycles. For motorized vehicles, opening times are currently Monday to Friday from 5:20Β a.m. to 8:00Β p.m. and on Saturdays from 5:20Β a.m. to 4:00Β p.m.
Discussed on
- "Old Elbe Tunnel" | 2022-10-12 | 147 Upvotes 54 Comments
π The Amiga Smart File System
The Smart File System (SFS) is a journaling filesystem used on Amiga computers and AmigaOS-derived operating systems (though some support also exists for IBM PC compatibles). It is designed for performance, scalability and integrity, offering improvements over standard Amiga filesystems as well as some special or unique features.
Discussed on
- "The Amiga Smart File System" | 2019-09-01 | 129 Upvotes 32 Comments
π Umbral Calculus
In mathematics before the 1970s, the term umbral calculus referred to the surprising similarity between seemingly unrelated polynomial equations and certain "shadowy" techniques used to "prove" them. These techniques were introduced by John BlissardΒ (1861) and are sometimes called Blissard's symbolic method. They are often attributed to Γdouard Lucas (or James Joseph Sylvester), who used the technique extensively.
π State Capture
State capture is a type of systemic political corruption in which private interests significantly influence a state's decision-making processes to their own advantage.
The term was first used by the World Bank in 2000 to describe certain Central Asian countries making the transition from Soviet communism, where small corrupt groups used their influence over government officials to appropriate government decision-making in order to strengthen their own economic positions.
Allegations of state capture have led to protests against the government in Bulgaria in 2013β2014 and in 2020β2021 and Romania in 2017, and have caused an ongoing controversy in South Africa beginning in 2016. Turkey is considered as a post-2002 example of state capture. The term has also been used against Elon Musk by critics of U.S. President Donald Trump.
Discussed on
- "State Capture" | 2025-02-14 | 67 Upvotes 41 Comments
π Wikipedia frequently-encountered sources, color-coded by perceived reliability
This is a non-exhaustive list of sources whose reliability and use on Wikipedia are frequently discussed. This list summarizes prior consensus and consolidates links to the most in-depth and recent discussions from the reliable sources noticeboard and elsewhere on Wikipedia.
- Click here to check the list of sources.
Context matters tremendously, and some sources may or may not be suitable for certain uses depending on the situation. When in doubt, defer to the linked discussions for more detailed information on a particular source and its use. Consensus can change, and if more recent discussions considering new evidence or arguments reach a different consensus, this list should be updated to reflect those changes.
Reliability is an inquiry that takes place pursuant to the verifiability policy and the reliable sources guideline. Note that verifiability is only one of Wikipedia's core content policies, which also include neutral point of view and no original research. These policies work together to determine whether information from reliable sources should be included or excluded.
Discussed on
- "Wikipedia's List of Reliable Sources" | 2022-12-27 | 12 Upvotes 4 Comments
- "Wikipedia: Reliable Sources/Perennial Sources" | 2022-04-29 | 10 Upvotes 1 Comments
- "Wikipedia frequently-encountered sources, color-coded by perceived reliability" | 2021-01-08 | 99 Upvotes 79 Comments