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🔗 Alternative education

A Sudbury school is a type of school, usually for the K-12 age range, where students have complete responsibility for their own education, and the school is run by a direct democracy in which students and staff are equal citizens. Students use their time however they wish, and learn as a by-product of ordinary experience rather than through coursework. There is no predetermined educational syllabus, prescriptive curriculum or standardized instruction. This is a form of democratic education. Daniel Greenberg, one of the founders of the original Sudbury Model school, writes that the two things that distinguish a Sudbury Model school are that everyone - adults and children - are treated equally and that there is no authority other than that granted by the consent of the governed.

While each Sudbury Model school operates independently and determines their own policies and procedures, they share a common culture. The intended culture within a Sudbury school has been described with such words as freedom, trust, respect, responsibility and democracy.

The name 'Sudbury' originates from the Sudbury Valley School, founded in 1968 in Framingham, Massachusetts, near Sudbury, Massachusetts. Though there is no formal or regulated definition of a Sudbury Model school, there are now more than 60 schools that identify themselves with Sudbury around the world. Some, though not all, include "Sudbury" in their name. These schools operate as independent entities and are not formally associated in any way.

🔗 Oceans 🔗 Polymers

The Indian Ocean garbage patch, discovered in 2010, is a gyre of marine litter suspended in the upper water column of the central Indian Ocean, specifically the Indian Ocean Gyre, one of the five major oceanic gyres. The patch does not appear as a continuous debris field. As with other patches in each of the five oceanic gyres, the plastics in it break down to ever smaller particles, and to constituent polymers. As with the other patches, the field constitutes an elevated level of pelagic plastics, chemical sludge, and other debris; primarily particles that are invisible to the naked eye. The concentration of particle debris has been estimated to be approximately 10,000 particles per square kilometer.

A similar patch of floating plastic debris in the Pacific Ocean, the Great Pacific garbage patch, was predicted in 1985, and discovered in 1997 by Charles J. Moore as he passed through the North Pacific Gyre on his return from the Transpacific Yacht Race. The North Atlantic garbage patch was discovered in 2010.

🔗 Computer science 🔗 Mathematics

CORDIC (for COordinate Rotation DIgital Computer), also known as Volder's algorithm, or: Digit-by-digit method Circular CORDIC (Jack E. Volder), Linear CORDIC, Hyperbolic CORDIC (John Stephen Walther), and Generalized Hyperbolic CORDIC (GH CORDIC) (Yuanyong Luo et al.), is a simple and efficient algorithm to calculate trigonometric functions, hyperbolic functions, square roots, multiplications, divisions, and exponentials and logarithms with arbitrary base, typically converging with one digit (or bit) per iteration. CORDIC is therefore also an example of digit-by-digit algorithms. CORDIC and closely related methods known as pseudo-multiplication and pseudo-division or factor combining are commonly used when no hardware multiplier is available (e.g. in simple microcontrollers and FPGAs), as the only operations it requires are additions, subtractions, bitshift and lookup tables. As such, they all belong to the class of shift-and-add algorithms. In computer science, CORDIC is often used to implement floating-point arithmetic when the target platform lacks hardware multiply for cost or space reasons.

🔗 United States 🔗 Languages 🔗 United States/Mississippi

"Thank God for Mississippi" is an adage used in the United States, particularly in the South, that is generally used when discussing rankings of U.S. states. Since the U.S. state of Mississippi commonly ranks at or near the bottom of such rankings, residents of other states also ranking near the bottom may say, "Thank God for Mississippi," since the presence of that state in 50th place spares them the shame of being ranked last.

Examples include rankings of educational achievement, business opportunities, political progressiveness, obesity rates, overall health, the poverty rate, life expectancy, or other objective criteria of the quality of life or government in the 50 states. The phrase is in use even among state government officials and journalists, though occasionally with a slight twist.

Mississippi's poor reputation is such a common trope in American culture that when Mississippi does indeed rank well in something, the phrase "Thank God for Mississippi" may get brought up just to discuss how it does not apply in the given circumstance. The saying comes from Mississippi's poor ranking as compared to the other 49 states, not from a global perspective.

🔗 Measurement

ISO 1 is an international standard set by the International Organization for Standardization that specifies the standard reference temperature for geometrical product specification and verification. The temperature is fixed at 20 °C, which is equal to 293.15 kelvins and 68 degrees Fahrenheit.

Due to thermal expansion, precision length measurements need to be made at (or converted to) a defined temperature. ISO 1 helps in comparing measurements by defining such a reference temperature. The reference temperature of 20 °C was adopted by the CIPM on 15 April 1931, and became ISO recommendation number 1 in 1951. It soon replaced worldwide other reference temperatures for length measurements that manufacturers of precision equipment had used before, including 0 °C, 62 °F, and 25 °C. Among the reasons for choosing 20 °C was that this was a comfortable and practical workshop temperature and that it resulted in an integer value on both the Celsius and Fahrenheit scales.

🔗 Mathematics

A mathematical coincidence is said to occur when two expressions with no direct relationship show a near-equality which has no apparent theoretical explanation.

For example, there is a near-equality close to the round number 1000 between powers of 2 and powers of 10:

${\displaystyle 2^{10}=1024\approx 1000=10^{3}.}$

Some mathematical coincidences are used in engineering when one expression is taken as an approximation of another.

🔗 Novels 🔗 Novels/Science fiction

The Invincible (Polish: Niezwyciężony) is a hard science fiction novel by Polish writer Stanisław Lem, published in 1964.

The Invincible originally appeared as the title story in Lem's collection Niezwyciężony i inne opowiadania ("The Invincible and Other Stories"). A translation into German was published in 1967; an English translation by Wendayne Ackerman, based on the German one, was published in 1973. A direct translation into English from Polish, by Bill Johnston, was published in 2006.

It was one of the first novels to explore the ideas of microrobots/smartdust/etc., artificial swarm intelligence and "necroevolution", a term suggested by Lem for evolution of non-living matter.

🔗 United States 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Law Enforcement

The Posse Comitatus Act is a United States federal law (18 U.S.C. § 1385, original at 20 Stat. 152) signed on June 18, 1878, by President Rutherford B. Hayes. The purpose of the act – in concert with the Insurrection Act of 1807 – is to limit the powers of the federal government in using federal military personnel to enforce domestic policies within the United States. It was passed as an amendment to an army appropriation bill following the end of Reconstruction and was updated in 1956 and 1981.

The act specifically applies only to the United States Army and, as amended in 1956, the United States Air Force. Although the act does not explicitly mention the United States Navy and the United States Marine Corps, the Department of the Navy has prescribed regulations that are generally construed to give the act force with respect to those services as well. The act does not prevent the Army National Guard or the Air National Guard under state authority from acting in a law enforcement capacity within its home state or in an adjacent state if invited by that state's governor. The United States Coast Guard (under the Department of Homeland Security) and United States Space Force (under the Department of the Air Force) are not covered by the Posse Comitatus Act either, primarily because although both are armed services, they also have maritime and space law enforcement missions respectively.

The title of the act comes from the legal concept of posse comitatus, the authority under which a county sheriff, or other law officer, conscripts any able-bodied person to assist in keeping the peace.

🔗 India 🔗 Numismatics 🔗 India/Indian politics workgroup

A zero-rupee note is a banknote imitation issued in India as a means of helping to fight systemic political corruption. The notes are "paid" in protest by angry citizens to government functionaries who solicit bribes in return for services which are supposed to be free. Zero-rupee notes, which are made to resemble the old 50-rupee banknote of India, are the creation of a non-governmental organization known as 5th Pillar which has, since their inception in 2007, distributed over 2.5 million notes as of August 2014. The notes remain in current use and thousands of notes are distributed every month.

🔗 Economics 🔗 Statistics

The gravity model of international trade in international economics is a model that, in its traditional form, predicts bilateral trade flows based on the economic sizes and distance between two units.

The model was first introduced in economics world by Walter Isard in 1954. The basic model for trade between two countries (i and j) takes the form of

${\displaystyle F_{ij}=G*{\frac {M_{i}*M_{j}}{D_{ij}}}}$

In this formula G is a constant, F stands for trade flow, D stands for the distance and M stands for the economic dimensions of the countries that are being measured. The equation can be changed into a linear form for the purpose of econometric analyses by employing logarithms. The model has been used by economists to analyse the determinants of bilateral trade flows such as common borders, common languages, common legal systems, common currencies, common colonial legacies, and it has been used to test the effectiveness of trade agreements and organizations such as the North American Free Trade Agreement (NAFTA) and the World Trade Organization (WTO) (Head and Mayer 2014). The model has also been used in international relations to evaluate the impact of treaties and alliances on trade (Head and Mayer).

The model has also been applied to other bilateral flow data (also 'dyadic' data) such as migration, traffic, remittances and foreign direct investment.