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🔗 Mathematics

The hairy ball theorem of algebraic topology (sometimes called the hedgehog theorem in Europe) states that there is no nonvanishing continuous tangent vector field on even-dimensional n-spheres. For the ordinary sphere, or 2‑sphere, if f is a continuous function that assigns a vector in R³ to every point p on a sphere such that f(p) is always tangent to the sphere at p, then there is at least one p such that f(p) = 0. The theorem was first stated by Henri Poincaré in the late 19th century, and first proven in 1912 by Luitzen Egbertus Jan Brouwer.

The theorem has been expressed colloquially as "you can't comb a hairy ball flat without creating a cowlick" or "you can't comb the hair on a coconut".

🔗 United States 🔗 Law

In re Bilski, 545 F.3d 943, 88 U.S.P.Q.2d 1385 (Fed. Cir. 2008), was an en banc decision of the United States Court of Appeals for the Federal Circuit (CAFC) on the patenting of method claims, particularly business methods. The Federal Circuit court affirmed the rejection of the patent claims involving a method of hedging risks in commodities trading. The court also reiterated the machine-or-transformation test as the (meaning sole) applicable test for patent-eligible subject matter, and stated that the test in State Street Bank v. Signature Financial Group should no longer be relied upon.

The Supreme Court of the United States issued an opinion on appeal (as Bilski v. Kappos) that affirmed the judgment of the CAFC, but revised many aspects of the CAFC's decision. In its decision, handed down on June 28, 2010, the Supreme Court rejected the machine-or-transformation test as the sole test of process patent eligibility based on an interpretation of the language of § 101. The majority, however, had high praise for the Federal Circuit opinions, advising that "[s]tudents of patent law would be well advised to study these scholarly opinions."

🔗 Europe 🔗 Middle Ages 🔗 Middle Ages/History

An erdstall is a type of tunnel found across Europe. They are of unknown origin but are believed to date from the Middle Ages. A variety of purposes have been theorized, including that they were used as escape routes or hiding places, but the most prominent theory is that they served a religious or spiritual purpose.

🔗 Companies 🔗 China 🔗 Organized Labour

The 996 working hour system (Chinese: 996工作制) is a work schedule commonly practiced by some companies in the People's Republic of China. It derives its name from its requirement that employees work from 9:00 am to 9:00 pm, 6 days per week; i.e. 72 hours per week. A number of Chinese internet companies have adopted this system as their official work schedule. Critics argue that the 996 working hour system is a flagrant violation of Chinese law.

In March 2019 an "anti-996" protest was launched via GitHub.

🔗 Finance & Investment 🔗 Economics 🔗 Business 🔗 Rock music 🔗 Business/Accounting

A celebrity bond is commercial debt security issued by a holder of fame-based intellectual property rights to receive money upfront from investors on behalf of the bond issuer and their celebrity clients in exchange for assigning investors the right to collect future royalty monies to the works covered by the intellectual property rights listed in the bond. Typically backed by music properties, the investment vehicle was pioneered in 1997 by rock and roll investment banker David Pullman through his $55 million David Bowie bond deal.

🔗 Germany 🔗 Military history 🔗 Military history/World War II 🔗 Military history/German military history 🔗 Jewish history 🔗 Military history/European military history

Kristallnacht (German pronunciation: [kʁɪsˈtalnaχt]) or the Night of Broken Glass, also called the November Pogrom(s), was a pogrom against Jews carried out by SA paramilitary forces and civilians throughout Nazi Germany on 9–10 November 1938. The German authorities looked on without intervening. The name Kristallnacht ("Crystal Night") comes from the shards of broken glass that littered the streets after the windows of Jewish-owned stores, buildings and synagogues were smashed.

Jewish homes, hospitals and schools were ransacked as the attackers demolished buildings with sledgehammers. The rioters destroyed 267 synagogues throughout Germany, Austria and the Sudetenland. Over 7,000 Jewish businesses were damaged or destroyed, and 30,000 Jewish men were arrested and incarcerated in concentration camps. British historian Martin Gilbert wrote that no event in the history of German Jews between 1933 and 1945 was so widely reported as it was happening, and the accounts from foreign journalists working in Germany sent shockwaves around the world. The Times of London observed on 11 November 1938: "No foreign propagandist bent upon blackening Germany before the world could outdo the tale of burnings and beatings, of blackguardly assaults on defenceless and innocent people, which disgraced that country yesterday."

The pretext for the attacks was the assassination of the Nazi German diplomat Ernst vom Rath by Herschel Grynszpan, a 17-year-old German-born Polish Jew living in Paris. Estimates of fatalities caused by the attacks have varied. Early reports estimated that 91 Jews had been murdered. Modern analysis of German scholarly sources puts the figure much higher; when deaths from post-arrest maltreatment and subsequent suicides are included, the death toll climbs into the hundreds, with Richard J. Evans estimating 638 suicide deaths. Historians view Kristallnacht as a prelude to the Final Solution and the murder of six million Jews during the Holocaust.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Military history/Russian, Soviet and CIS military history 🔗 Military history/Post-Cold War

The Poseidon (Russian: Посейдон, "Poseidon", NATO reporting name Kanyon), previously known by Russian codename Status-6 (Russian: Статус-6), is an autonomous, nuclear-powered, and nuclear-armed unmanned underwater vehicle under development by Rubin Design Bureau, capable of delivering both conventional and nuclear payloads.

The Poseidon is one of the six new Russian strategic weapons announced by Russian President Vladimir Putin on 1 March 2018.

🔗 Telecommunications

A payphone (alternative spelling: pay phone) is typically a coin-operated public telephone, often located in a telephone booth or in high-traffic outdoor areas, with pre-payment by inserting money (usually coins) or by billing a credit or debit card, or a telephone card. Prepaid calling cards also facilitate establishing a call by first calling the provided toll-free telephone number, entering the card account number and PIN, then the desired telephone number. An equipment usage fee may be charged as additional units, minutes or tariff fee to the collect/third-party, debit, credit, telephone or prepaid calling card when used at payphones. By agreement with the landlord, either the phone company pays rent for the location and keeps the revenue, or the landlord pays rent for the phone and shares the revenue.

Payphones are often found in public places to contribute to the notion of universal access to basic communication services. One thesis, written as early as 2003, recognised this as a digital divide problem.

In the 20th century, payphones in some countries, such as Spain, used token coins, available for sale at a local retailer, to activate pay phones, instead of legal tender coins. In some cases, these were upgraded to use magnetic cards or credit card readers over the years.

In the past, payphones were ubiquitous worldwide, but their prevalence has decreased significantly over the years due to the increasing availability of mobile phones, even though cell phone service is not always available in emergencies.

🔗 Germany 🔗 Military history 🔗 Military history/Maritime warfare 🔗 Military history/World War II 🔗 Military history/German military history 🔗 Military history/European military history

German submarine U-1206 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. She was laid down on 12 June 1943 at F. Schichau GmbH in Danzig and went into service on 16 March 1944 before sinking a year later, in April 1945. The boat's emblem was a white stork on a black shield with green beak and legs.

🔗 Soviet Union

Homo Sovieticus (Dog Latin for "Soviet Man") is a pejorative for an average conformist person in the Soviet Union and other countries of the Eastern Bloc. The term was popularized by Soviet writer and sociologist Aleksandr Zinovyev, who wrote the book titled Homo Sovieticus.

Michel Heller asserted that the term was coined in the introduction of a 1974 monograph "Sovetskye lyudi" ("Soviet People") to describe the next level of evolution of humanity thanks to the success of Marxist social experiment.

In a book published in 1981, but available in samizdat in the 1970s, Zinovyev also coined an abbreviation homosos (гомосос, literally a homosucker).