Random Articles (Page 4)

Have a deep view into what people are curious about.

πŸ”— Caproni Ca.60

πŸ”— Aviation πŸ”— Aviation/aircraft

The Caproni Ca.60 Transaereo, often referred to as the Noviplano (nine-wing) or Capronissimo, was the prototype of a large nine-wing flying boat intended to become a 100-passenger transatlantic airliner. It featured eight engines and three sets of triple wings.

Only one example of this aircraft, designed by Italian aviation pioneer Gianni Caproni, was built by the Caproni company. It was tested on Lake Maggiore in 1921: its brief maiden flight took place on February 12 or March 2. Its second flight was March 4; shortly after takeoff, the aircraft crashed on the water surface and broke up upon impact. The Ca.60 was further damaged when the wreck was towed to shore and, in spite of Caproni's intention to rebuild the aircraft, the project was soon abandoned because of its excessive cost. The few surviving parts are on display at the Gianni Caproni Museum of Aeronautics and at the Volandia aviation museum in Italy.

Discussed on

πŸ”— 1989 California Medfly Attack

πŸ”— California πŸ”— Environment πŸ”— Terrorism πŸ”— Agriculture

In 1989, a sudden invasion of Mediterranean fruit flies (Ceratitis capitata, "medflies") appeared in California and began devastating crops. Scientists were puzzled and said that the sudden appearance of the insects "defies logic", and some speculated "biological terrorists" were responsible. Analysis suggested that an outside hand played a role in the dense infestation.

A person or group calling itself "The Breeders" took responsibility for the bioterrorist attack, as financial retaliation for the environmental damage caused by the state's Malathion aerial spraying; the group's members were never identified. Subsequently, three months after "The Breeders" announced the medfly release, the state ended its decade-long Malathion program and sought alternate ways to handle destructive insects.

Discussed on

πŸ”— OK Soda

πŸ”— Food and drink πŸ”— Brands πŸ”— Food and drink/Beverages

OK Soda was a soft drink created by The Coca-Cola Company in 1993 that courted the American Generation X demographic with unusual advertising tactics, including neo-noir design, chain letters and deliberately negative publicity. After the soda did not sell well in select test markets, it was officially declared out of production in 1995 before reaching nationwide distribution. The drink's slogan was "Things are going to be OK."

Discussed on

πŸ”— Kramatorsk Radiological Accident

πŸ”— Disaster management πŸ”— Ukraine

The Kramatorsk radiological accident was a radiation accident that happened in Kramatorsk, in the Ukrainian SSR from 1980 to 1989. A small capsule containing highly radioactive caesium-137 was found inside the concrete wall of an apartment building, with a surface gamma radiation exposure dose rate of 1800Β R/year. The capsule was detected only after residents requested that the level of radiation in the apartment be measured by a health physicist.

The capsule was originally part of a radiation level gauge and was lost in the Karansky quarry in the late 1970s. The search for the capsule was unsuccessful and ended after a week. The gravel from the quarry was used in construction. The caesium capsule ended up in the concrete panel of apartment 85 of building 7 on Mariyi Pryimachenko Street (at the time under the Soviet name Gvardeytsiv Kantemirovtsiv), between apartments 85 and 52.

Over nine years, two families lived in apartment 85. A child's bed was located directly next to the wall containing the capsule. The apartment was fully settled in 1980. A year later, an 18-year-old woman who lived there suddenly died. In 1982, her 16-year-old brother followed, and then their mother. Even after that the flat did not attract much public attention, despite the fact that the residents all died from leukemia. Doctors were unable to determine root-cause of illness and explained the diagnosis by poor heredity. A new family moved into the apartment, and their son died from leukemia as well. His father managed to start a detailed investigation, during which the vial was found in the wall in 1989.

By the time the capsule was discovered, four residents of the building had died from it and 17 more had received varying doses of radiation. Part of the wall was removed and sent to the Institute for Nuclear Research, where the caesium capsule was removed, identified by serial number and disposed of.

Discussed on

πŸ”— Old Stockholm Telephone Tower

πŸ”— Sweden

The Old Stockholm telephone tower (Swedish: Telefontornet) was a metallic structure built to connect approximately 5,500 telephone lines in the Swedish capital of Stockholm. Constructed in 1887, the tower was used until 1913. It was damaged by a fire in 1952 and demolished the following year.

Discussed on

πŸ”— Operation Vegetarian

πŸ”— Military history πŸ”— Military history/World War II πŸ”— Scottish Islands

Operation Vegetarian was a British military plan in 1942 to disseminate linseed cakes infected with anthrax spores onto the fields of Germany. These cakes would have been eaten by the cattle, which would then be consumed by the civilian population, causing the deaths of millions of German citizens. Furthermore, it would have wiped out the majority of Germany's cattle, creating a massive food shortage for the rest of the population that remained uninfected. Preparations were not complete until early 1944. Operation Vegetarian was only to be used in the event of a German anthrax attack on the United Kingdom.

The cakes themselves were tested on Gruinard Island, just off the coast of Scotland. Because of the widespread contamination from the anthrax spores, the land remained quarantined until 1990. The five million cakes made to be disseminated in Germany were eventually destroyed in an incinerator shortly after the end of World War II.

In his novel The Impossible Dead (2011), author Ian Rankin mentions the clandestine events surrounding the removal of contaminated soils from Guinard Island by a protest group, the Dark Harvest Commando, and the island's removal from maps by the British Government. The island also features as the principal setting for the 1985 novel El aΓ±o de gracia, by Cristina FernΓ‘ndez Cubas, in which the protagonist spends a winter shipwrecked on the island.

Discussed on

πŸ”— Artificio de Juanelo

The Artificio de Juanelo ("Gianello's artifice") was the name of two devices built in Toledo in the 16th century by Juanelo Turriano. They were designed to supply the city with a source of readily available water by lifting it from the Tagus (Tajo) river to the AlcΓ‘zar. Now in ruins, the precise details of the operation of the devices are unknown, but at the time they were considered engineering wonders.

Discussed on

πŸ”— Jaccard Index

πŸ”— Computer science πŸ”— 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 communautΓ©, 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:

J ( A , B ) = | A ∩ B | | A βˆͺ B | = | A ∩ B | | A | + | B | βˆ’ | A ∩ B | . {\displaystyle J(A,B)={{|A\cap B|} \over {|A\cup B|}}={{|A\cap B|} \over {|A|+|B|-|A\cap B|}}.}

Note that by design, 0 ≀ J ( A , B ) ≀ 1. {\displaystyle 0\leq J(A,B)\leq 1.} If A intersection B is empty, then J(A,B)Β =Β 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.

J ( A , B ) = | A ∩ B | | A ⊎ B | = | A ∩ B | | A | + | B | . {\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:

d J ( A , B ) = 1 βˆ’ J ( A , B ) = | A βˆͺ B | βˆ’ | A ∩ B | | A βˆͺ B | . {\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 A β–³ B = ( A βˆͺ B ) βˆ’ ( A ∩ B ) {\displaystyle A\triangle B=(A\cup B)-(A\cap B)} to the union. Jaccard distance is commonly used to calculate an n Γ— 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 ΞΌ {\displaystyle \mu } is a measure on a measurable space X {\displaystyle X} , then we define the Jaccard coefficient by

J ΞΌ ( A , B ) = ΞΌ ( A ∩ B ) ΞΌ ( A βˆͺ B ) , {\displaystyle J_{\mu }(A,B)={{\mu (A\cap B)} \over {\mu (A\cup B)}},}

and the Jaccard distance by

d ΞΌ ( A , B ) = 1 βˆ’ J ΞΌ ( A , B ) = ΞΌ ( A β–³ B ) ΞΌ ( A βˆͺ B ) . {\displaystyle d_{\mu }(A,B)=1-J_{\mu }(A,B)={{\mu (A\triangle B)} \over {\mu (A\cup B)}}.}

Care must be taken if ΞΌ ( A βˆͺ B ) = 0 {\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.

Discussed on

πŸ”— Krista and Tatiana Hogan

πŸ”— Biography πŸ”— Canada πŸ”— Psychology πŸ”— Disability

Krista and Tatiana Hogan (born October 25, 2006) are Canadians who are conjoined craniopagus twins. They are joined at the head and share a skull and a brain. They were born in Vancouver, British Columbia, and are the only unseparated conjoined twins of that type currently alive in Canada. They live with their mother, Felicia Simms, in Vernon, British Columbia, have two sisters and a brother and often travel to Vancouver for care at BC Children's Hospital and Sunny Hill Health Centre for Children.

πŸ”— Cyclomatic Complexity

πŸ”— Computing πŸ”— Computer science πŸ”— Computing/Software

Cyclomatic complexity is a software metric used to indicate the complexity of a program. It is a quantitative measure of the number of linearly independent paths through a program's source code. It was developed by Thomas J. McCabe, Sr. in 1976.

Cyclomatic complexity is computed using the control-flow graph of the program: the nodes of the graph correspond to indivisible groups of commands of a program, and a directed edge connects two nodes if the second command might be executed immediately after the first command. Cyclomatic complexity may also be applied to individual functions, modules, methods or classes within a program.

One testing strategy, called basis path testing by McCabe who first proposed it, is to test each linearly independent path through the program; in this case, the number of test cases will equal the cyclomatic complexity of the program.

Discussed on