Cohn Ronald

High Quality Content by WIKIPEDIA articles! The Rh (Rhesus) blood group system (including the Rh factor) is one of thirty current human blood group systems. Clinically, it is the most important blood group system after ABO. At Present, the Rh blood group system consists of 50 defined blood-group antigens, among which the 5 antigens D, C, c, E, and e are the most important. The commonly-used terms Rh factor, Rh positive and Rh negative refer to the D antigen only. Besides its role in blood transfusion, the Rh blood group system, the D antigen, in particular, is a relevant cause of the hemolytic disease of the newborn or erythroblastosis fetalis for which prevention is key.

High Quality Content by WIKIPEDIA articles! A thesaurus is a reference work that lists words grouped together according to similarity of meaning (containing synonyms and sometimes antonyms), in contrast to a dictionary, which contains definitions and pronunciations. The largest thesaurus in the world is the Historical Thesaurus of the Oxford English Dictionary, which contains more than 920,000 entries.

High Quality Content by WIKIPEDIA articles! Tuple calculus is a calculus that was introduced by Edgar F. Codd as part of the relational model, in order to provide a declarative database-query language for this data model. It formed the inspiration for the database-query languages QUEL and SQL, of which the latter, although far less faithful to the original relational model and calculus, is now the de-facto-standard database-query language; viz., a dialect of SQL is used by nearly every relational-database-management system. Lacroix and Pirotte proposed domain calculus, which is closer to first-order logic and which showed that both of these calculi (as well as relational algebra) are equivalent in expressive power. Subsequently, query...

High Quality Content by WIKIPEDIA articles! In telecommunications, a scrambler is a device that transposes or inverts signals or otherwise encodes a message at the transmitter to make the message unintelligible at a receiver not equipped with an appropriately set descrambling device. Whereas encryption usually refers to operations carried out in the digital domain, scrambling usually refers to operations carried out in the analog domain. Scrambling is accomplished by the addition of components to the original signal or the changing of some important component of the original signal in order to make extraction of the original signal difficult. Examples of the latter might include removing or changing vertical or horizontal sync pulses in...

High Quality Content by WIKIPEDIA articles! Torpor, sometimes called temporary hibernation is a (usually short-term) state of decreased physiological activity in an animal, usually characterized by a reduced body temperature and rate of metabolism. Animals that go through torpor include birds (even tiny hummingbirds, notably Cypselomorphae) and some mammals such as mice and bats. During the active part of their day, animals that undergo daily torpor maintain normal body temperature and activity levels, but their temperature drops during a portion of the day (usually night) to conserve energy. Torpor is often used to help animals survive during periods of colder temperatures, as it allows the organism to save the amount of energy that...

High Quality Content by WIKIPEDIA articles! A scorched earth policy is a military strategy or operational method which involves destroying anything that might be useful to the enemy while advancing through or withdrawing from an area. Although initially referring to the practice of burning crops to deny the enemy food sources, in its modern usage the term includes the destruction of infrastructure such as shelter, transportation, communications and industrial resources. The practice may be carried out by an army in enemy territory, or its own home territory. It may overlap with, but is not the same as, punitive destruction of an enemy`s resources, which is done for purely strategic/political reasons rather than strategic/operational...

High Quality Content by WIKIPEDIA articles! Pterygota is a subclass of insects that includes the winged insects. It also includes insect orders that are secondarily wingless (that is, insect groups whose ancestors once had wings but that have lost them as a result of subsequent evolution).

High Quality Content by WIKIPEDIA articles! The Royal Grammar School Worcester (also known as RGS Worcester) is an independent coeducational school in Worcester, United Kingdom. Founded before 1291, it is one of the oldest British independent schools.

High Quality Content by WIKIPEDIA articles! A thermocline (sometimes metalimnion) is a thin but distinct layer in a large body of fluid (e.g. water, such as an ocean or lake, or air, such as an atmosphere), in which temperature changes more rapidly with depth than it does in the layers above or below. In the ocean, the thermocline may be thought of as an invisible blanket which separates the upper mixed layer from the calm deep water below. Depending largely on season, latitude and turbulent mixing by wind, thermoclines may be a semi-permanent feature of the body of water in which they occur, or they may form temporarily in response to phenomena such as the radiative heating/cooling of surface water during the day/night. Factors that...

High Quality Content by WIKIPEDIA articles! Science (from Latin scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. An older and closely related meaning still in use today is that found for example in Aristotle, whereby "science" refers to the body of reliable knowledge itself, of the type that can be logically and rationally explained (see "History and etymology" section below).

High Quality Content by WIKIPEDIA articles! Tug of war, also known as tug o` war, tug war, rope war or rope pulling, is a sport that directly pits two teams against each other in a test of strength. The term may also be used as a metaphor to describe a demonstration of brute strength by two opposing groups, such as a rivalry between two departments of a company. In this scenario, there is often a third party who is considered the "rope" in the tug of war.

High Quality Content by WIKIPEDIA articles! Thermal pollution is the degradation of water quality by any process that changes ambient water temperature.

High Quality Content by WIKIPEDIA articles! Regenerative design (sometimes referred to as cradle-to-cradle design) is a process-oriented systems theory based approach to design. The term "regenerative" describes processes that restore, renew or revitalize their own sources of energy and materials, creating sustainable systems that integrate the needs of society with the integrity of nature. The basis is derived from systems ecology with a closed loop input–output model or a model in which the output is greater than or equal to the input with all outputs viable and all inputs accounted for. Regenerative design is the biomimicry of ecosystems that provide for all human systems to function as a closed viable ecological economics system...

High Quality Content by WIKIPEDIA articles! Quantum fingerprinting is a proposed technique that uses a quantum computer to generate a string with a similar function to the cryptographic hash function.

High Quality Content by WIKIPEDIA articles! Ptarmigan Island is one of the many uninhabited Canadian arctic islands in Qikiqtaaluk Region, Nunavut. It is a Baffin Island offshore island located in Frobisher Bay, southeast of the capital city of Iqaluit. Other islands in the immediate vicinity include Aubrey Island, Beveridge Island, Coffin Island, Emerick Island, and Thompson Island.

High Quality Content by WIKIPEDIA articles! The RSA Secret-Key Challenge consisted of a series of cryptographic contests organised by RSA Laboratories with the intent of helping to demonstrate the relative security of different encryption algorithms. The challenge ran from 28 January 1997 until May 2007.

High Quality Content by WIKIPEDIA articles! The Thermal Oxide Reprocessing Plant, or THORP, is a nuclear fuel reprocessing plant at Sellafield in Cumbria, England. THORP is owned by the Nuclear Decommissioning Authority and operated by Sellafield Ltd (which is the site licensee company). Spent nuclear fuel from nuclear reactors is reprocessed to separate the 96% uranium and the 1% plutonium, which can be reused in mixed oxide fuel, from the 3% radioactive wastes, which are treated and stored at the plant. The uranium is then made available for customers to be manufactured into new fuel.

High Quality Content by WIKIPEDIA articles! In physics, the Schwinger model, named after Julian Schwinger, is the model describing 2D Euclidean quantum electrodynamics with a Dirac fermion. This model exhibits a spontaneous symmetry breaking of the U(1) symmetry due to a chiral condensate due to a pool of instantons. The photon in this model becomes a massive particle at low temperatures. This model can be solved exactly and is used as a toy model for other more complex theories.

High Quality Content by WIKIPEDIA articles! A Quantum Digital Signature (QDS) refers to the quantum mechanical equivalent of either a classical digital signature or, more generally, a handwritten signature on a paper document. Like a handwritten signature, a digital signature is used to protect a document, such as a digital contract, against forgery by another party or by one of the participating parties.

High Quality Content by WIKIPEDIA articles! The Procolophonia are a suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period. They were originally included as a suborder of the Cotylosauria (later renamed Captorhinida Carroll 1988) but are now considered a clade of Parareptilia. They are closely related to other generally lizard-like Permian reptiles such as the Millerettidae, Bolosauridae, Acleistorhinidae, Lanthanosuchidae, and Nyctiphruretidae, all of which are included under the Anapsida or "Parareptiles" (as opposed to the Eureptilia).

High Quality Content by WIKIPEDIA articles! Thermal insulation is the reduction of the effects of the various processes of heat transfer between objects in thermal contact or in range of radiative influence. Heat transfer is the transfer of thermal energy between objects of differing temperature. The means to stem heat flow may be especially engineered methods or processes, as well as suitable static objects and materials.