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🔗 Geology 🔗 Rocks and minerals 🔗 Iceland

Iceland spar, formerly called Iceland crystal (Icelandic: silfurberg [ˈsɪlvʏrˌpɛrk], lit. 'silver-rock') and also called optical calcite, is a transparent variety of calcite, or crystallized calcium carbonate, originally brought from Iceland, and used in demonstrating the polarization of light.

🔗 European history

A whipping boy was a boy educated alongside a prince (or boy monarch) in early modern Europe, who received corporal punishment for the prince's transgressions in his presence. The prince was not punished himself because his royal status exceeded that of his tutor; seeing a friend punished would provide an equivalent motivation not to repeat the offence. An archaic proverb which captures a similar idea is "to beat a dog before a lion." Whipping was a common punishment of tutors at that time. There is little contemporary evidence for the existence of whipping boys, and evidence that some princes were indeed whipped by their tutors, although Nicholas Orme suggests that nobles might have been beaten less often than other pupils. Some historians regard whipping boys as entirely mythical; others suggest they applied only in the case of a boy king, protected by divine right, and not to mere princes.

In Renaissance humanism, Erasmus' treatises "The Education of a Christian Prince" (1516) and "Declamatio de pueris statim ac liberaliter instituendis" (1530) mention the inappropriateness of physical chastisement of princes, but do not mention proxy punishment. Hartley Coleridge wrote in 1852, "to be flogged by proxy was the exclusive privilege of royal blood. ... It was much coveted for the children of the poorer gentry, as the first step in the ladder of preferment." John Gough Nichols wrote in 1857, "the whole matter is somewhat legendary, and though certain vicarious or rather minatory punishments may have been occasionally adopted, it does not seem likely that any one individual among the King's schoolfellows should have been uniformly selected, whether he were in fault or not, as the victim or scape-goat of the royal misdemeanours". In current English, a "whipping boy" is a metaphor which may have a similar meaning to scapegoat, fall guy, or sacrificial lamb; alternatively it may mean a perennial loser or a victim of group bullying.

🔗 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.

🔗 United States 🔗 Africa 🔗 African diaspora 🔗 United States/Kentucky 🔗 Africa/Liberia

Kentucky in Africa was a colony in present-day Montserrado County, Liberia, founded in 1828 and settled by American free people of color, many of them former slaves. A state affiliate of the American Colonization Society, the Kentucky State Colonization Society raised money to transport people of color from Kentucky—freeborn volunteers as well as enslaved individuals set free on the condition that they leave the United States for Liberia. The Kentucky society bought a 40-square-mile (100 km²) site along the Saint Paul River (quite near the site of the present-day capital city of Monrovia) and named it Kentucky in Africa. Clay-Ashland. named after Henry Clay's Ashland Plantation, was the colony's primary settlement.

Notable residents of Kentucky in Africa include Alfred Francis Russell, the 10th President of Liberia, and William D. Coleman, the 13th President of Liberia, whose family settled in Clay-Ashland after emigrating from Fayette County, Kentucky.

Kentucky in Africa was annexed by Liberia in about 1847.

🔗 Computer science 🔗 Statistics

The Jaccard index, also known as the Jaccard similarity coefficient, is a statistic used for gauging the similarity and diversity of sample sets. It was developed by Grove Karl Gilbert in 1884 as his ratio of verification (v) and now is frequently referred to as the Critical Success Index in meteorology. It was later developed independently by Paul Jaccard, originally giving the French name coefficient de communauté, and independently formulated again by T. Tanimoto. Thus, the Tanimoto index or Tanimoto coefficient are also used in some fields. However, they are identical in generally taking the ratio of Intersection over Union. The Jaccard coefficient measures similarity between finite sample sets, and is defined as the size of the intersection divided by the size of the union of the sample sets:

${\displaystyle J(A,B)={{|A\cap B|} \over {|A\cup B|}}={{|A\cap B|} \over {|A|+|B|-|A\cap B|}}.}$

Note that by design, ${\displaystyle 0\leq J(A,B)\leq 1.}$ If A intersection B is empty, then J(A,B) = 0. The Jaccard coefficient is widely used in computer science, ecology, genomics, and other sciences, where binary or binarized data are used. Both the exact solution and approximation methods are available for hypothesis testing with the Jaccard coefficient.

Jaccard similarity also applies to bags, i.e., Multisets. This has a similar formula, but the symbols mean bag intersection and bag sum (not union). The maximum value is 1/2.

${\displaystyle J(A,B)={{|A\cap B|} \over {|A\uplus B|}}={{|A\cap B|} \over {|A|+|B|}}.}$

The Jaccard distance, which measures dissimilarity between sample sets, is complementary to the Jaccard coefficient and is obtained by subtracting the Jaccard coefficient from 1, or, equivalently, by dividing the difference of the sizes of the union and the intersection of two sets by the size of the union:

${\displaystyle d_{J}(A,B)=1-J(A,B)={{|A\cup B|-|A\cap B|} \over |A\cup B|}.}$

An alternative interpretation of the Jaccard distance is as the ratio of the size of the symmetric difference ${\displaystyle A\triangle B=(A\cup B)-(A\cap B)}$ to the union. Jaccard distance is commonly used to calculate an n × n matrix for clustering and multidimensional scaling of n sample sets.

This distance is a metric on the collection of all finite sets.

There is also a version of the Jaccard distance for measures, including probability measures. If ${\displaystyle \mu }$ is a measure on a measurable space ${\displaystyle X}$, then we define the Jaccard coefficient by

${\displaystyle J_{\mu }(A,B)={{\mu (A\cap B)} \over {\mu (A\cup B)}},}$

and the Jaccard distance by

${\displaystyle d_{\mu }(A,B)=1-J_{\mu }(A,B)={{\mu (A\triangle B)} \over {\mu (A\cup B)}}.}$

Care must be taken if ${\displaystyle \mu (A\cup B)=0}$ or ${\displaystyle \infty }$, since these formulas are not well defined in these cases.

The MinHash min-wise independent permutations locality sensitive hashing scheme may be used to efficiently compute an accurate estimate of the Jaccard similarity coefficient of pairs of sets, where each set is represented by a constant-sized signature derived from the minimum values of a hash function.

🔗 Climate change 🔗 Environment 🔗 Antarctica 🔗 Glaciers

The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea.

🔗 Russia 🔗 Politics 🔗 Discrimination

Managed nationalism or controlled nationalism (Russian: Управляемый национализм, romanized: Upravlyayemyy natsionalizm) is a term used by some academics to refer to an informal policy of pragmatic collaboration with Russian nationalists and neo-Nazis (or in broader cases, the Russian far-right as a whole) pursued by the government of Russia under Vladimir Putin. Beginning after Putin's election as President of Russia in 2000 and escalating after the 2004 Orange Revolution in Ukraine, managed nationalism led to the promotion of the Russian Image organisation throughout the late 2000s until the 2009 murders of human rights activists Stanislav Markelov and Anastasia Baburova, at which point Russian Image was dissolved.

Since the 2011–2013 Russian protests and Euromaidan, managed nationalism has faced a revival, with far-right militants supporting the anti-Maidan and Novorossiya. The policy of managed nationalism is closely linked to other Russian government policies of promoting neo-Nazism and other far-right movements in foreign countries.

🔗 Statistics 🔗 Books

How to Lie with Statistics is a book written by Darrell Huff in 1954, presenting an introduction to statistics for the general reader. Not a statistician, Huff was a journalist who wrote many how-to articles as a freelancer.

The book is a brief, breezy illustrated volume outlining the misuse of statistics and errors in the interpretation of statistics, and how errors create incorrect conclusions.

In the 1960s and 1970s, it became a standard textbook introduction to the subject of statistics for many college students. It has become one of the best-selling statistics books in history, with over one and a half million copies sold in the English-language edition. It has also been widely translated.

Themes of the book include "Correlation does not imply causation" and "Using random sampling." It also shows how statistical graphs can be used to distort reality. For example, by truncating the bottom of a line or bar chart so that differences seem larger than they are. Or, by representing one-dimensional quantities on a pictogram by two- or three-dimensional objects to compare their sizes so that the reader forgets that the images do not scale the same way the quantities do.

The original edition contained illustrations by artist Irving Geis. In a UK edition, Geis' illustrations were replaced by cartoons by Mel Calman.

🔗 Finance & Investment 🔗 Economics

Financialization (or financialisation in British English) is a term sometimes used to describe the development of financial capitalism during the period from 1980 to present, in which debt-to-equity ratios increased and financial services accounted for an increasing share of national income relative to other sectors.

Financialization describes an economic process by which exchange is facilitated through the intermediation of financial instruments. Financialization may permit real goods, services, and risks to be readily exchangeable for currency, and thus make it easier for people to rationalize their assets and income flows.

🔗 Microbiology 🔗 Marine life 🔗 Tree of Life

Parakaryon myojinensis, also known as the Myojin parakaryote, is a highly unusual species of single-celled organism known only from a single specimen, described in 2012. It has features of both prokaryotes and eukaryotes but is apparently distinct from either group, making it unique among organisms discovered thus far. It is the sole species in the genus Parakaryon. It is part of the domain Parakarya.