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🔗 United States 🔗 Trains 🔗 United States/Ohio 🔗 Trains/Rapid transit 🔗 United States/Cincinnati

The Cincinnati Subway is a set of incomplete, derelict tunnels and stations for a rapid transit system beneath the streets of Cincinnati, Ohio. Although it is only a little over 2 miles in length, it is the largest abandoned subway tunnel system in the United States. Construction began in the early 1900s as an upgrade to the Cincinnati streetcar system, but was abandoned due to escalating costs, the collapse of funding amidst political bickering, and the Great Depression during the 1920s and 1930s.

In 1928, the construction of the subway system in Cincinnati was indefinitely canceled. There are no plans to revive the project.

🔗 Human rights 🔗 Russia 🔗 Death 🔗 Iran 🔗 Discrimination 🔗 Turkey 🔗 Ethnic groups 🔗 Russia/politics and law of Russia 🔗 Russia/history of Russia 🔗 Caucasia 🔗 Crime and Criminal Biography 🔗 Abkhazia

The Circassian genocide, or Tsitsekun, was the systematic mass killing, ethnic cleansing, and forced displacement of between 95% and 97% of the Circassian people during the final stages of the Russian invasion of Circassia in the 19th century. It resulted in the deaths of between 1,000,000 and 1.5 million and the destruction of Circassia, which was then annexed by the Russian Empire. Those planned for extermination were mainly the Circassians, who are predominantly Muslims, but other ethnic groups in the Caucasus were also affected, as part of the Caucasian War. The Imperial Russian Army also impaled their victims and tore open the bellies of pregnant women to intimidate the Circassians and devastate their morale. Many Russian generals, such as Grigory Zass, described the Circassians as a "lowly race" to justify and glorify their wholesale slaughter and their use as human test subjects in unethical scientific experiments. Russian soldiers were also permitted to rape Circassian women.

The native Circassian population was largely decimated or expelled to the Ottoman Empire. Only those who accepted Russification and made agreements with Russian troops, were spared. Starvation was used as a tool of war against Circassian villages, many of which were subsequently burned down. Russian writer Leo Tolstoy reported that Russian soldiers attacked village houses at night. British diplomat Gifford Palgrave, stated that "their only crime was not being Russian." Seeking military intervention against Russia, Circassian officials sent "A Petition from Circassian leaders to Her Majesty Queen Victoria" in 1864, but were unsuccessful in their attempt to solicit aid from the British Empire. That same year, the Imperial Russian Army launched a campaign of mass deportation of Circassia's surviving population. By 1867, a large portion of the Circassians were expelled. Many died from epidemics or starvation. Some were reportedly eaten by dogs after their death, while others died when their ships sank during storms of black sea.

Most sources state that as little as 3% of Circassia's population remained after the genocide and that as many as 1.5 million people were forced to flee in total, though only around half of them survived the journey. Ottoman archives show the intake of more than a million immigrants from the Caucasus by 1879, with nearly half of them having been found dying on the shores of the Black Sea as a result of disease. Presuming that these statistics are accurate, Russia's military campaign in Circassia constitutes the single largest genocide of the 19th century. Russian records, in confirmation of the Ottoman archives, documented the presence of only 106,798 Circassians in the Caucasus on the approach to the 20th century. Other estimates by Russian historiographers are even lower, ranging from 40,400 to 65,900. The Russian Empire census, conducted in 1897, reported the presence of 150,000 Circassians in the conquered region.

Classified Russian Imperial archives in Georgia were opened to historians by the Georgian government, which revealed previously unknown information regarding Russian actions. Following this, on May 20, 2011, Georgia formally recognized the Circassian genocide. Ukraine recognized the Circassian genocide on 9 January 2025, following Circassian appeals in June 2024. The city of Wayne, New Jersey in the United States and the East Turkistan Exile Government have also officially recognized the Circassian genocide. On February 7, 1992, the Kabardino-Balkarian Autonomous Soviet Socialist Republic decided to condemn the Circassian Genocide. On May 12, 1994, the Republic of Kabardino-Balkaria and on April 29, 1996, the Republic of Adygea submitted applications to the State Duma of the Russian Federation for the recognition of the Circassian Genocide. In October 2006, 20+ Circassian associations appealed to the European Parliament to recognize the Circassian Genocide. In November 2006, Circassian associations in the Republics of Adygea, Kabardino-Balkaria and Karachay-Cherkessia appealed to Russian president Vladimir Putin to recognize the Circassian Genocide. The Russian Federation classifies the events in Circassia as a mass migration (Russian: Черкесское мухаджирство, lit. 'Circassian migrationism') and denies that a genocide took place. 21 May is observed annually as the Circassian Day of Mourning, which consists of ceremonies and marches in memory of the victims and, sometimes, protests against the Russian government. Today, the Circassian diaspora is primarily concentrated in Turkey and Jordan, with some 750,000 living in Russia's North Caucasus Economic Region.

🔗 Mathematics 🔗 Festivals

Pi Day is an annual celebration of the mathematical constant π (pi). Pi Day is observed on March 14 (3/14 in the month/day format) since 3, 1, and 4 are the first three significant digits of π. In 2009, the United States House of Representatives supported the designation of Pi Day. UNESCO's 40th General Conference decided Pi Day as the International Day of Mathematics in November 2019.

Pi Approximation Day is observed on July 22 (22/7 in the day/month format), since the fraction ​²²⁄₇ is a common approximation of π, which is accurate to two decimal places and dates from Archimedes.

Two Pi Day, also known as Tau Day for the mathematical constant Tau, is observed on June 28 (6/28 in the month/day format).

🔗 Economics 🔗 Education 🔗 Game theory 🔗 Games

A simulation game is "a game that contains a mixture of skill, chance, and strategy to simulate an aspect of reality, such as a stock exchange". Similarly, Finnish author Virpi Ruohomäki states that "a simulation game combines the features of a game (competition, cooperation, rules, participants, roles) with those of a simulation (incorporation of critical features of reality). A game is a simulation game if its rules refer to an empirical model of reality". A properly built simulation game used to teach or learn economics would closely follow the assumptions and rules of the theoretical models within this discipline.

🔗 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.

🔗 China 🔗 Novels 🔗 Novels/Science fiction 🔗 Science Fiction

The Dark Forest (Chinese: 黑暗森林) is a 2008 science fiction novel by the Chinese writer Liu Cixin. It is the sequel to the Hugo Award-winning novel The Three-Body Problem in the trilogy titled Remembrance of Earth's Past, but Chinese readers generally refer to the series by the title of the first novel. The English version, translated by Joel Martinsen, was published in 2015. The novel is about the dark forest hypothesis (which was named after the novel), a possible solution to the Fermi paradox, though similar theories have been described as early as 1983.

🔗 Biography 🔗 Mathematics 🔗 France 🔗 Women scientists 🔗 Biography/science and academia 🔗 Women's History 🔗 Mathematics/Mathematicians

Marie-Sophie Germain (French: [maʁi sɔfi ʒɛʁmɛ̃]; 1 April 1776 – 27 June 1831) was a French mathematician, physicist, and philosopher. Despite initial opposition from her parents and difficulties presented by society, she gained education from books in her father's library, including ones by Leonhard Euler, and from correspondence with famous mathematicians such as Lagrange, Legendre, and Gauss (under the pseudonym of «Monsieur LeBlanc»). One of the pioneers of elasticity theory, she won the grand prize from the Paris Academy of Sciences for her essay on the subject. Her work on Fermat's Last Theorem provided a foundation for mathematicians exploring the subject for hundreds of years after. Because of prejudice against her sex, she was unable to make a career out of mathematics, but she worked independently throughout her life. Before her death, Gauss had recommended that she be awarded an honorary degree, but that never occurred. On 27 June 1831, she died from breast cancer. At the centenary of her life, a street and a girls’ school were named after her. The Academy of Sciences established the Sophie Germain Prize in her honor.

🔗 New York City 🔗 Engineering

The Citicorp Center engineering crisis was the discovery, in 1978, of a significant structural flaw in Citicorp Center, then a recently completed skyscraper in New York City, and the subsequent effort to quietly make repairs over the next few months. The building, now known as Citigroup Center, occupied an entire block and was to be the headquarters of Citibank. Its structure, designed by William LeMessurier, had several unusual design features, including a raised base supported by four offset stilts, and diagonal bracing which absorbed wind loads from upper stories.

In the original design, potential wind loads for the building were calculated incorrectly. The flaw was discovered by Diane Hartley, an undergraduate student at Princeton University who was writing a thesis on the building, and was communicated to the firm responsible for the structural design. LeMessurier was subsequently lauded for acknowledging his error and orchestrating a successful repair effort. Estimates at the time suggested that the building could be toppled by a 70-mile-per-hour (110 km/h) wind, with possibly many people killed as a result. The crisis was kept secret until 1995 and Hartley had no knowledge of the significance of her work until after that time.

🔗 Mathematics

A squircle is a shape intermediate between a square and a circle. There are at least two definitions of "squircle" in use, the most common of which is based on the superellipse. The word "squircle" is a portmanteau of the words "square" and "circle". Squircles have been applied in design and optics.

🔗 Technology 🔗 Sweden 🔗 Metalworking

Gauge blocks (also known as gage blocks, Johansson gauges, slip gauges, or Jo blocks) are a system for producing precision lengths. The individual gauge block is a metal or ceramic block that has been precision ground and lapped to a specific thickness. Gauge blocks come in sets of blocks with a range of standard lengths. In use, the blocks are stacked to make up a desired length.

An important feature of gauge blocks is that they can be joined together with very little dimensional uncertainty. The blocks are joined by a sliding process called wringing, which causes their ultra-flat surfaces to cling together. A small number of gauge blocks can be used to create accurate lengths within a wide range. By using 3 blocks at a time taken from a set of 30 blocks, one may create any of the 1000 lengths from 3.000 to 3.999 mm in 0.001 mm steps (or .3000 to .3999 inches in 0.0001 inch steps). Gauge blocks were invented in 1896 by Swedish machinist Carl Edvard Johansson. They are used as a reference for the calibration of measuring equipment used in machine shops, such as micrometers, sine bars, calipers, and dial indicators (when used in an inspection role). Gauge blocks are the main means of length standardization used by industry.