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🔗 Rome

Secessio plebis (withdrawal of the commoners, or secession of the plebs) was an informal exercise of power by Rome's plebeian citizens, similar in concept to the general strike. During the secessio plebis, the plebs would abandon the city en masse and leave the patrician order to themselves. Therefore, a secessio meant that all shops and workshops would shut down and commercial transactions would largely cease. This was an effective strategy in the Conflict of the Orders due to strength in numbers; plebeian citizens made up the vast majority of Rome's populace and produced most of its food and resources, while a patrician citizen was a member of the minority upper class, the equivalent of the landed gentry of later times. Authors report different numbers for how many secessions there were. Cary & Scullard state there were five between 494 BC and 287 BC.

🔗 Philosophy 🔗 Philosophy/Logic 🔗 Philosophy/Epistemology

In epistemology, the Münchhausen trilemma is a thought experiment used to demonstrate the impossibility of proving any truth, even in the fields of logic and mathematics. If it is asked how any given proposition is known to be true, proof may be provided. Yet that same question can be asked of the proof, and any subsequent proof. The Münchhausen trilemma is that there are only three options when providing further proof in response to further questioning:

• The circular argument, in which the proof of some proposition is supported only by that proposition
• The regressive argument, in which each proof requires a further proof, ad infinitum
• The axiomatic argument, which rests on accepted precepts which are merely asserted rather than defended

The trilemma, then, is the decision among the three equally unsatisfying options.

The name Münchhausen-Trilemma was coined by the German philosopher Hans Albert in 1968 in reference to a trilemma of "dogmatism versus infinite regress versus psychologism" used by Karl Popper. It is a reference to the problem of "bootstrapping", based on the story of Baron Munchausen (in German, "Münchhausen") pulling himself and the horse on which he was sitting out of a mire by his own hair.

It is also known as Agrippa's trilemma or the Agrippan trilemma after a similar argument reported by Sextus Empiricus, which was attributed to Agrippa the Skeptic by Diogenes Laërtius, as well as Fries's trilemma after German philosopher Jakob Friedrich Fries. Sextus' argument, however, consists of five (not three) "modes". Popper in his original 1935 publication mentions neither Sextus nor Agrippa, but attributes his trilemma to Fries.

In contemporary epistemology, advocates of coherentism are supposed to accept the "circular" horn of the trilemma; foundationalists rely on the axiomatic argument. The view that accepts infinite regress is called infinitism.

🔗 Military history 🔗 Military history/Military aviation 🔗 Military history/World War II 🔗 Military history/German military history 🔗 Military history/European military history 🔗 Military history/British military history

The Charlie Brown and Franz Stigler incident occurred on 20 December 1943, when, after a successful bomb run on Bremen, 2nd Lt Charles "Charlie" Brown's B-17 Flying Fortress (named "Ye Olde Pub") was severely damaged by German fighters. Luftwaffe pilot Franz Stigler had the opportunity to shoot down the crippled bomber but did not do so. After an extensive search by Brown, the two pilots met each other 50 years later and developed a friendship that lasted until Stigler's death in March 2008.

🔗 Computer science

The inner-platform effect is the tendency of software architects to create a system so customizable as to become a replica, and often a poor replica, of the software development platform they are using. This is generally inefficient and such systems are often considered to be examples of an anti-pattern.

🔗 United States 🔗 Human rights 🔗 History 🔗 Politics 🔗 Politics/American politics 🔗 African diaspora 🔗 United States History 🔗 United States/FBI 🔗 Civil Rights Movement 🔗 United States/U.S. history

COINTELPRO (syllabic abbreviation derived from COunter INTELligence PROgram) (1956–1971) was a series of covert and, at times, illegal projects conducted by the United States Federal Bureau of Investigation (FBI) aimed at surveilling, infiltrating, discrediting, and disrupting American political organizations. FBI records show that COINTELPRO resources targeted groups and individuals that the FBI deemed subversive, including feminist organizations, the Communist Party USA, anti–Vietnam War organizers, activists of the civil rights movement or Black Power movement (e.g. Martin Luther King Jr., the Nation of Islam, and the Black Panther Party), environmentalist and animal rights organizations, the American Indian Movement (AIM), independence movements (such as Puerto Rican independence groups like the Young Lords), and a variety of organizations that were part of the broader New Left. The program also targeted the Ku Klux Klan in 1964.

In another instance in San Diego, the FBI financed, armed, and controlled an extreme right-wing group of former members of the Minutemen anti-communist para-military organization, transforming it into a group called the Secret Army Organization that targeted groups, activists, and leaders involved in the Anti-War Movement, using both intimidation and violent acts.

The FBI has used covert operations against domestic political groups since its inception; however, covert operations under the official COINTELPRO label took place between 1956 and 1971. COINTELPRO tactics are still used to this day and have been alleged to include discrediting targets through psychological warfare; smearing individuals and groups using forged documents and by planting false reports in the media; harassment; wrongful imprisonment; and illegal violence, including assassination. The FBI's stated motivation was "protecting national security, preventing violence, and maintaining the existing social and political order".

Beginning in 1969, leaders of the Black Panther Party were targeted by the COINTELPRO and "neutralized" by being assassinated, imprisoned, publicly humiliated or falsely charged with crimes. Some of the Black Panthers affected included Fred Hampton, Mark Clark, Zayd Shakur, Geronimo Pratt, Mumia Abu-Jamal, and Marshall Conway. Common tactics used by COINTELPRO were perjury, witness harassment, witness intimidation, and withholding of evidence.

FBI Director J. Edgar Hoover issued directives governing COINTELPRO, ordering FBI agents to "expose, disrupt, misdirect, discredit, or otherwise neutralize" the activities of these movements and especially their leaders. Under Hoover, the agent in charge of COINTELPRO was William C. Sullivan. Attorney General Robert F. Kennedy personally authorized some of the programs. Although Kennedy only gave written approval for limited wiretapping of Martin Luther King's phones "on a trial basis, for a month or so", Hoover extended the clearance so his men were "unshackled" to look for evidence in any areas of King's life they deemed worthy.

🔗 Glass

Uranium glass is glass which has had uranium, usually in oxide diuranate form, added to a glass mix before melting for coloration. The proportion usually varies from trace levels to about 2% uranium by weight, although some 20th-century pieces were made with up to 25% uranium.

Uranium glass was once made into tableware and household items, but fell out of widespread use when the availability of uranium to most industries was sharply curtailed during the Cold War in the 1940s to 1990s. Most such objects are now considered antiques or retro-era collectibles, although there has been a minor revival in art glassware. Otherwise, modern uranium glass is now mainly limited to small objects like beads or marbles as scientific or decorative novelties.

🔗 Computer science 🔗 Linguistics 🔗 Languages

Attempto Controlled English (ACE) is a controlled natural language, i.e. a subset of standard English with a restricted syntax and restricted semantics described by a small set of construction and interpretation rules. It has been under development at the University of Zurich since 1995. In 2013, ACE version 6.7 was announced.

ACE can serve as knowledge representation, specification, and query language, and is intended for professionals who want to use formal notations and formal methods, but may not be familiar with them. Though ACE appears perfectly natural – it can be read and understood by any speaker of English – it is in fact a formal language.

ACE and its related tools have been used in the fields of software specifications, theorem proving, text summaries, ontologies, rules, querying, medical documentation and planning.

Here are some simple examples:

1. Every woman is a human.
2. A woman is a human.
3. A man tries-on a new tie. If the tie pleases his wife then the man buys it.

ACE construction rules require that each noun be introduced by a determiner (a, every, no, some, at least 5, ...). Regarding the list of examples above, ACE interpretation rules decide that (1) is interpreted as universally quantified, while (2) is interpreted as existentially quantified. Sentences like "Women are human" do not follow ACE syntax and are consequently not valid.

Interpretation rules resolve the anaphoric references in (3): the tie and it of the second sentence refer to a new tie of the first sentence, while his and the man of the second sentence refer to a man of the first sentence. Thus an ACE text is a coherent entity of anaphorically linked sentences.

The Attempto Parsing Engine (APE) translates ACE texts unambiguously into discourse representation structures (DRS) that use a variant of the language of first-order logic. A DRS can be further translated into other formal languages, for instance AceRules with various semantics, OWL, and SWRL. Translating an ACE text into (a fragment of) first-order logic allows users to reason about the text, for instance to verify, to validate, and to query it.

🔗 Biography 🔗 Computer science 🔗 Biography/science and academia 🔗 Denmark

Peter Naur (25 October 1928 – 3 January 2016) was a Danish computer science pioneer and Turing award winner. His last name is the "N" in the BNF notation (Backus–Naur form), used in the description of the syntax for most programming languages. He contributed to the creation of the ALGOL 60 programming language.

🔗 Aviation 🔗 Aviation/rotorcraft

Jesus nut is a slang term for the main rotor retaining nut or mast nut, which holds the main rotor to the mast of some helicopters. The related slang term Jesus pin refers to the lock pin used to secure the retaining nut. More generally, Jesus nut (or Jesus pin) has been used to refer to any component that is a single point of failure which results in catastrophic consequences.

🔗 Computer science

Boids is an artificial life program, developed by Craig Reynolds in 1986, which simulates the flocking behaviour of birds. His paper on this topic was published in 1987 in the proceedings of the ACM SIGGRAPH conference. The name "boid" corresponds to a shortened version of "bird-oid object", which refers to a bird-like object. Incidentally, "boid" is also a New York Metropolitan dialect pronunciation for "bird".

As with most artificial life simulations, Boids is an example of emergent behavior; that is, the complexity of Boids arises from the interaction of individual agents (the boids, in this case) adhering to a set of simple rules. The rules applied in the simplest Boids world are as follows:

• separation: steer to avoid crowding local flockmates
• alignment: steer towards the average heading of local flockmates
• cohesion: steer to move towards the average position (center of mass) of local flockmates

More complex rules can be added, such as obstacle avoidance and goal seeking.

The basic model has been extended in several different ways since Reynolds proposed it. For instance, Delgado-Mata et al. extended the basic model to incorporate the effects of fear. Olfaction was used to transmit emotion between animals, through pheromones modelled as particles in a free expansion gas. Hartman and Benes introduced a complementary force to the alignment that they call the change of leadership. This steer defines the chance of the boid to become a leader and try to escape.

The movement of Boids can be characterized as either chaotic (splitting groups and wild behaviour) or orderly. Unexpected behaviours, such as splitting flocks and reuniting after avoiding obstacles, can be considered emergent.

The boids framework is often used in computer graphics, providing realistic-looking representations of flocks of birds and other creatures, such as schools of fish or herds of animals. It was for instance used in the 1998 video game Half-Life for the flying bird-like creatures seen at the end of the game on Xen, named "boid" in the game files.

The Boids model can be used for direct control and stabilization of teams of simple Unmanned Ground Vehicles (UGV) or Micro Aerial Vehicles (MAV) in swarm robotics. For stabilization of heterogeneous UAV-UGV teams, the model was adapted for using onboard relative localization by Saska et al.

At the time of proposal, Reynolds' approach represented a giant step forward compared to the traditional techniques used in computer animation for motion pictures. The first animation created with the model was Stanley and Stella in: Breaking the Ice (1987), followed by a feature film debut in Tim Burton's film Batman Returns (1992) with computer generated bat swarms and armies of penguins marching through the streets of Gotham City.

The boids model has been used for other interesting applications. It has been applied to automatically program Internet multi-channel radio stations. It has also been used for visualizing information and for optimization tasks.