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🔗 Internet 🔗 Computing 🔗 Freedom of speech 🔗 Computing/Websites

GitHub has been the target of censorship from governments using methods ranging from local Internet service provider blocks, intermediary blocking using methods such as DNS hijacking and man-in-the-middle attacks, and denial-of-service attacks on GitHub's servers from countries including China, India, Russia, and Turkey. In all of these cases, GitHub has been eventually unblocked after backlash from users and technology businesses or compliance from GitHub.

🔗 Physics

In the philosophy of thermal and statistical physics, the Brownian ratchet or Feynman–Smoluchowski ratchet is an apparent perpetual motion machine of the second kind, first analysed in 1912 as a thought experiment by Polish physicist Marian Smoluchowski. It was popularised by American Nobel laureate physicist Richard Feynman in a physics lecture at the California Institute of Technology on May 11, 1962, during his Messenger Lectures series The Character of Physical Law in Cornell University in 1964 and in his text The Feynman Lectures on Physics as an illustration of the laws of thermodynamics. The simple machine, consisting of a tiny paddle wheel and a ratchet, appears to be an example of a Maxwell's demon, able to extract mechanical work from random fluctuations (heat) in a system at thermal equilibrium, in violation of the second law of thermodynamics. Detailed analysis by Feynman and others showed why it cannot actually do this.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Medicine 🔗 Chemicals 🔗 Occupational Safety and Health 🔗 Military history/World War I 🔗 Medicine/Toxicology

Chloropicrin, also known as PS and nitrochloroform, is a chemical compound currently used as a broad-spectrum antimicrobial, fungicide, herbicide, insecticide, and nematicide. It was used as a poison gas in World War I. Its chemical structural formula is Cl₃CNO₂.

🔗 Biography 🔗 Military history 🔗 Military history/Military aviation 🔗 Military history/Military biography 🔗 Military history/World War II 🔗 Military history/Russian, Soviet and CIS military history

Ivan Mikhailovich Chisov (Russian: Иван Михайлович Чисов, Ukrainian: Іван Михайлович Чиссов; 1916–1986) was a Soviet Air Force lieutenant who survived a fall of approximately 7,000 meters (23,000 feet). Some references give the spelling of his last name as Chissov (Russian: Чиссов, Ukrainian: Чиссов).

🔗 Computer science 🔗 Systems 🔗 Human–Computer Interaction

In artificial intelligence, an expert system is a computer system emulating the decision-making ability of a human expert. Expert systems are designed to solve complex problems by reasoning through bodies of knowledge, represented mainly as if–then rules rather than through conventional procedural code. The first expert systems were created in the 1970s and then proliferated in the 1980s. Expert systems were among the first truly successful forms of artificial intelligence (AI) software. An expert system is divided into two subsystems: the inference engine and the knowledge base. The knowledge base represents facts and rules. The inference engine applies the rules to the known facts to deduce new facts. Inference engines can also include explanation and debugging abilities.

🔗 New Zealand

Taumatawhakatangi­hangakoauauotamatea­turipukakapikimaunga­horonukupokaiwhen­uakitanatahu is a hill near Porangahau, south of Waipukurau in southern Hawke's Bay, New Zealand. The height of the hill is 305 metres (1,001 ft). The hill is notable primarily for its unusually long name, which is of Māori origin; it is often shortened to Taumata for brevity. It has gained a measure of fame as it is the longest place name found in any English-speaking country, and possibly the longest place name in the world; according to World Atlas. The name of the hill (with 85 characters) has also been listed in the Guinness World Records as the longest place name. Other versions of the name, including longer ones, are also sometimes used.

🔗 Philosophy 🔗 Philosophy/Logic 🔗 Philosophy/Epistemology

The unexpected hanging paradox or hangman paradox is a paradox about a person's expectations about the timing of a future event which they are told will occur at an unexpected time. The paradox is variously applied to a prisoner's hanging, or a surprise school test. It could be reduced to be Moore's paradox.

Despite significant academic interest, there is no consensus on its precise nature and consequently a final correct resolution has not yet been established. Logical analysis suggests that the problem arises in a self-contradictory self-referencing statement at the heart of the judge's sentence. Epistemological studies of the paradox have suggested that it turns on our concept of knowledge. Even though it is apparently simple, the paradox's underlying complexities have even led to its being called a "significant problem" for philosophy.

🔗 United States 🔗 Finance & Investment

The Onion Futures Act is a United States law banning the trading of futures contracts on onions as well as "motion picture box office receipts".

In 1955, two onion traders, Sam Siegel and Vincent Kosuga, cornered the onion futures market on the Chicago Mercantile Exchange. The resulting regulatory actions led to the passing of the act on August 28, 1958. As of January 2020, it remains in effect.

🔗 United States/U.S. Government 🔗 Internet culture 🔗 Telecommunications 🔗 Law 🔗 Politics 🔗 Popular Culture 🔗 Donald Trump

The Communications Over Various Feeds Electronically for Engagement Act (COVFEFE Act) is a bill introduced into the United States House of Representatives in 2017 (on June 12), during the 115th United States Congress.

The bill would amend the Presidential Records Act to preserve Twitter posts and other social media interactions of the President of the United States, and to require the National Archives to store such items.

U.S. Representative Mike Quigley, Democrat of Illinois, introduced the legislation in the wake of Donald Trump's routine use of Twitter, stating "In order to maintain public trust in government, elected officials must answer for what they do and say; this includes 140-character tweets. If the president is going to take to social media to make sudden public policy proclamations, we must ensure that these statements are documented and preserved for future reference." If enacted, the bill "would bar the prolifically tweeting president from deleting his posts, as he has sometimes done."

If the bill were enacted, it would see US law treat US presidents' personal social media accounts (such as Trump's "@realDonaldTrump" Twitter account) the same as "official" social media accounts (such as the "@POTUS" Twitter account).

🔗 Computing 🔗 Mathematics

In mathematical logic and type theory, the λ-cube is a framework introduced by Henk Barendregt to investigate the different dimensions in which the calculus of constructions is a generalization of the simply typed λ-calculus. Each dimension of the cube corresponds to a new kind of dependency between terms and types. Here, "dependency" refers to the capacity of a term or type to bind a term or type. The respective dimensions of the λ-cube correspond to:

• y-axis (${\displaystyle \uparrow }$): terms that can bind types, corresponding to polymorphism.
• x-axis (${\displaystyle \rightarrow }$): types that can bind terms, corresponding to dependent types.
• z-axis (${\displaystyle \nearrow }$): types that can bind types, corresponding to (binding) type operators.

The different ways to combine these three dimension yield the 8 vertices of the cube, each corresponding to a different kind of typed system. The λ-cube can be generalized into the concept of a pure type system.