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Polish–Czechoslovak Confederation
The Polish-Czechoslovak confederation, or federation, was a political concept from the time of World War II, supported by the Polish government-in-exile and, to a lesser extent, the United Kingdom and the United States . It was a revitalisation of the Międzymorze concept, proposing the creation of a federation based on Poland and Czechoslovakia. The project had less support in the Czechoslovak government-in-exile, which believed it did not need Polish support against the Soviet Union, and was eventually sunk by the growing Soviet dominance, as Joseph Stalin did not want a strong and independent federation in Europe that could threaten his designs for Eastern Europe.
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  • 14 Nov 2022
Topic Review
Neural Ensemble
A neural ensemble is a population of nervous system cells (or cultured neurons) involved in a particular neural computation.
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  • 14 Nov 2022
Topic Review
List of AMD Sempron Microprocessors
The Sempron is a name used for AMD's low-end CPUs, replacing the Duron processor. The name was introduced in 2004, and processors with this name continued to be available for the FM2/FM2+ socket in 2015.
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  • 14 Nov 2022
Topic Review
Cactus
A cactus (plural cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek word κάκτος (káktos), a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. Although some species live in quite humid environments, most cacti live in habitats subject to at least some drought. Many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on Earth. Because of this, cacti show many adaptations to conserve water. For example, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of true leaves, cacti's enlarged stems carry out photosynthesis. Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka. Cactus spines are produced from specialized structures called areoles, a kind of highly reduced branch. Areoles are an identifying feature of cacti. As well as spines, areoles give rise to flowers, which are usually tubular and multipetaled. Many cacti have short growing seasons and long dormancies and are able to react quickly to any rainfall, helped by an extensive but relatively shallow root system that quickly absorbs any water reaching the ground surface. Cactus stems are often ribbed or fluted, which allows them to expand and contract easily for quick water absorption after rain, followed by retention over long drought periods. Like other succulent plants, most cacti employ a special mechanism called "crassulacean acid metabolism" (CAM) as part of photosynthesis. Transpiration, during which carbon dioxide enters the plant and water escapes, does not take place during the day at the same time as photosynthesis, but instead occurs at night. The plant stores the carbon dioxide it takes in as malic acid, retaining it until daylight returns, and only then using it in photosynthesis. Because transpiration takes place during the cooler, more humid night hours, water loss is significantly reduced. Many smaller cacti have globe-shaped stems, combining the highest possible volume for water storage with the lowest possible surface area for water loss from transpiration. The tallest free-standing cactus is Pachycereus pringlei, with a maximum recorded height of 19.2 m (63 ft), and the smallest is Blossfeldia liliputiana, only about 1 cm (0.4 in) in diameter at maturity. A fully grown saguaro (Carnegiea gigantea) is said to be able to absorb as much as 200 U.S. gallons (760 l; 170 imp gal) of water during a rainstorm. A few species differ significantly in appearance from most of the family. At least superficially, plants of the genera Leuenbergeria, Rhodocactus and Pereskia resemble other trees and shrubs growing around them. They have persistent leaves, and when older, bark-covered stems. Their areoles identify them as cacti, and in spite of their appearance, they, too, have many adaptations for water conservation. Leuenbergeria is considered close to the ancestral species from which all cacti evolved. In tropical regions, other cacti grow as forest climbers and epiphytes (plants that grow on trees). Their stems are typically flattened, almost leaf-like in appearance, with fewer or even no spines, such as the well-known Christmas cactus or Thanksgiving cactus (in the genus Schlumbergera). Cacti have a variety of uses: many species are used as ornamental plants, others are grown for fodder or forage, and others for food (particularly their fruit). Cochineal is the product of an insect that lives on some cacti. Many succulent plants in both the Old and New World – such as some Euphorbiaceae (euphorbias) – are also spiny stem succulents and because of this are sometimes incorrectly referred to as "cactus".
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  • 14 Nov 2022
Topic Review
Komi (Go)
Komi (コミ) in the game of Go are points added to the score of the player with the white stones as compensation for playing second. Black's first move advantage is generally considered to equal somewhere between 5 and 7 points by the end of the game. Standard komi is 6.5 points under the Japanese and Korean rules; under Chinese, Ing and AGA rules standard komi is 7.5 points; under New Zealand rules standard komi is 7 points. Komi typically applies only to games where both players are evenly ranked. In the case of a one-rank difference, the stronger player will typically play with the white stones and players often agree on a simple 0.5-point komi to break a tie ("jigo") in favour of white, or no komi at all. Komidashi (コミ出し) is the more complete Japanese language term. The Chinese term is 贴目 (tiē mù) and the Korean term is Deom (덤).
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  • 14 Nov 2022
Topic Review
Einstein's Constant
Einstein's gravitational constant, denoted κ (kappa), is the constant appearing in the Einstein field equation which can be written: where Gαγ is the Einstein tensor and Tαγ is the stress–energy tensor. This equation relates to the curvature of spacetime, indicating that stress–energy is what causes the curvature of spacetime, thus gravitation. The constant κ is directly related to Newton's gravitational constant G: The above is for the stress–energy tensor in units of mass density (i.e., mass per volume). The units of Einstein's constant depends on how the stress–energy tensor is defined, so an alternative choice for T with units of energy density (i.e., energy per volume) yields
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  • 14 Nov 2022
Topic Review
CryptoLocker
The CryptoLocker ransomware attack was a cyberattack using the CryptoLocker ransomware that occurred from 5 September 2013 to late May 2014. The attack utilized a trojan that targeted computers running Microsoft Windows, and was believed to have first been posted to the Internet on 5 September 2013. It propagated via infected email attachments, and via an existing Gameover ZeuS botnet. When activated, the malware encrypted certain types of files stored on local and mounted network drives using RSA public-key cryptography, with the private key stored only on the malware's control servers. The malware then displayed a message which offered to decrypt the data if a payment (through either bitcoin or a pre-paid cash voucher) was made by a stated deadline, and it threatened to delete the private key if the deadline passes. If the deadline was not met, the malware offered to decrypt data via an online service provided by the malware's operators, for a significantly higher price in bitcoin. There was no guarantee that payment would release the encrypted content. Although CryptoLocker itself was easily removed, the affected files remained encrypted in a way which researchers considered unfeasible to break. Many said that the ransom should not be paid, but did not offer any way to recover files; others said that paying the ransom was the only way to recover files that had not been backed up. Some victims claimed that paying the ransom did not always lead to the files being decrypted. CryptoLocker was isolated in late May 2014 via Operation Tovar, which took down the Gameover ZeuS botnet that had been used to distribute the malware. During the operation, a security firm involved in the process obtained the database of private keys used by CryptoLocker, which was in turn used to build an online tool for recovering the keys and files without paying the ransom. It is believed that the operators of CryptoLocker successfully extorted a total of around $3 million from victims of the trojan. Other instances of encryption-based ransomware that have followed have used the "CryptoLocker" name (or variations), but are otherwise unrelated.
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  • 14 Nov 2022
Topic Review
Tyrocidine
Tyrocidine is a mixture of cyclic decapeptides produced by the bacteria Bacillus brevis found in soil. It can be composed of 4 different amino acid sequences, giving tyrocidine A–D. Tyrocidine is the major constituent of tyrothricin, which also contains gramicidin. Tyrocidine was the first commercially available antibiotic, but has been found to be toxic toward human blood and reproductive cells. The function of tyrocidine within its host B. brevis is thought to be regulation of sporulation. Tyrocidines A, B, and C are cyclic decapeptides. The biosynthesis of tyrocidine involves three enzymes. Parts of its sequence are identical to gramicidin S.
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  • 15 Nov 2022
Topic Review
Eurobonds
European bonds are proposed government bonds issued in euros jointly by the 19 eurozone nations. The idea was first raised by the European Commission in 2011. Eurobonds would be debt investments whereby an investor loans a certain amount of money, for a certain amount of time, with a certain interest rate, to the eurozone bloc altogether, which then forwards the money to individual governments. Eurobonds have been suggested as a way to tackle the European sovereign debt crisis as the indebted states could borrow new funds at better conditions as they are supported by the rating of the non-crisis states. Because Eurobonds would allow already highly indebted states access to cheaper credit thanks to the strength of other eurozone economies, they are controversial, and may suffer from the free rider problem.
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  • 14 Nov 2022
Topic Review
Rinderpest
Rinderpest (also cattle plague or steppe murrain) was an infectious viral disease of cattle, domestic buffalo, and many other species of even-toed ungulates, including gaurs, buffaloes, large antelope, deer, giraffes, wildebeests, and warthogs. The disease was characterized by fever, oral erosions, diarrhea, lymphoid necrosis, and high mortality. Death rates during outbreaks were usually extremely high, approaching 100% in immunologically naïve populations. Rinderpest was mainly transmitted by direct contact and by drinking contaminated water, although it could also be transmitted by air. After a global eradication campaign since the mid-20th century, the last confirmed case of rinderpest was diagnosed in 2001. On 14 October 2010, the United Nations Food and Agriculture Organization (FAO) announced that field activities in the decades-long, worldwide campaign to eradicate the disease were ending, paving the way for a formal declaration in June 2011 of the global eradication of rinderpest. On 25 May 2011, the World Organisation for Animal Health announced the free status of the last eight countries not yet recognized (a total of 198 countries were now free of the disease), officially declaring the eradication of the disease. In June 2011, the United Nations FAO confirmed the disease was eradicated, making rinderpest only the second disease in history to be fully wiped out (outside laboratory stocks), following smallpox. In June 2019 the UK destroyed its stocks of rinderpest virus, held at the Pirbright Institute in Surrey, which were most of the world's retained samples. This followed the completion of a digital record of the virus's genetic code, thereby obviating the need to store samples as a protective resource in case the virus re-emerges. Researchers at Pirbright and the United Nations expressed a hope that the other samples in laboratories around the world will also be destroyed, totally eradicating the virus from the Earth. Rinderpest is believed to have originated in Asia, later spreading through the transport of cattle. The term Rinderpest is a German word meaning "cattle-plague". The rinderpest virus (RPV) is closely related to the measles and canine distemper viruses. The measles virus possibly emerged from rinderpest as a zoonotic disease around 600 BC, a period that coincides with the rise of large human settlements.
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  • 13 Nov 2022
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