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1950 In Science
The year 1950 in science and technology included some significant events. Astronomy and space sciences * Dutch astronomer Jan Oort postulates the existence of an orbiting cloud of planets (the Oort cloud) at the outermost edge of the Solar System. * Enrico Fermi discusses the Fermi paradox. Biology * Melvin Calvin, James Bassham, and Andrew Benson at the University of California, Berkeley, discover the Calvin cycle in photosynthesis. * Entomologist Willi Hennig publishes ''Grundzüge einer Theorie der phylogenetischen Systematik'' in East Germany, pioneering the study of cladistics. * Full-scale release of myxomatosis for control of the Australian rabbit population. Chemistry * February 9 – Californium, a radioactive actinide transuranium element, is first synthesized by Stanley G. Thompson, Kenneth Street, Jr., Albert Ghiorso and Glenn T. Seaborg at the University of California, Berkeley. Computer science * March – Publication of Claude Shannon's paper "Programming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1950
Events January * January 1 – The International Police Association (IPA) – the largest police organization in the world – is formed. * January 5 – 1950 Sverdlovsk plane crash, Sverdlovsk plane crash: ''Aeroflot'' Lisunov Li-2 crashes in a snowstorm. All 19 aboard are killed, including almost the entire national ice hockey team (VVS Moscow) of the Soviet Air Force – 11 players, as well as a team doctor and a masseur. * January 6 – The UK recognizes the People's Republic of China; the Republic of China severs diplomatic relations with Britain in response. * January 7 – A fire in the St Elizabeth's Ward of Mercy Hospital in Davenport, Iowa, United States, kills 41 patients. * January 9 – The Israeli government recognizes the People's Republic of China. * January 12 – Submarine collides with Sweden, Swedish oil tanker ''Divina'' in the Thames Estuary and sinks; 64 die. * January 13 – Finland forms diplomatic relations with the People's Republic of China. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of California, Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant university and the founding campus of the University of California system. Its fourteen colleges and schools offer over 350 degree programs and enroll some 31,800 undergraduate and 13,200 graduate students. Berkeley ranks among the world's top universities. A founding member of the Association of American Universities, Berkeley hosts many leading research institutes dedicated to science, engineering, and mathematics. The university founded and maintains close relationships with three national laboratories at Berkeley, Livermore and Los Alamos, and has played a prominent role in many scientific advances, from the Manhattan Project and the discovery of 16 chemical elements to breakthroughs in computer science and genomics. Berkeley is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinide
The actinide () or actinoid () series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinide series derives its name from the first element in the series, actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide. The 1985 IUPAC ''Red Book'' recommends that ''actinoid'' be used rather than ''actinide'', since the suffix ''-ide'' normally indicates a negative ion. However, owing to widespread current use, ''actinide'' is still allowed. Since ''actinoid'' literally means ''actinium-like'' (cf. ''humanoid'' or ''android''), it has been argued for semantic reasons that actinium cannot logically be an actinoid, but IUPAC acknowledges its inclusion based on common usage. All the actinides are f-block elements, except the final one (lawrencium) which is a d-block element. Actinium has sometimes been considered d-block instead of lawrencium, but the class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Decay
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha decay ( ), beta decay ( ), and gamma decay ( ), all of which involve emitting one or more particles. The weak force is the mechanism that is responsible for beta decay, while the other two are governed by the electromagnetism and nuclear force. A fourth type of common decay is electron capture, in which an unstable nucleus captures an inner electron from one of the electron shells. The loss of that electron from the shell results in a cascade of electrons dropping down to that lower shell resulting in emission of discrete X-rays from the transitions. A common example is iodine-125 commonly used in medical settings. Radioactive decay is a stochastic (i.e. random) proce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Californium
Californium is a radioactive chemical element with the symbol Cf and atomic number 98. The element was first synthesized in 1950 at Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory), by bombarding curium with alpha particles ( helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all elements that have been produced in amounts large enough to see with the naked eye (after einsteinium). The element was named after the university and the U.S. state of California. Two crystalline forms exist for californium at normal pressure: one above and one below . A third form exists at high pressure. Californium slowly tarnishes in air at room temperature. Californium compounds are dominated by the +3 oxidation state. The most stable of californium's twenty known isotopes is californium-251, with a half-life of 898 years. This short half-life means the element is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rabbit
Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit species and its descendants, the world's 305 breeds of domestic rabbit. ''Sylvilagus'' includes 13 wild rabbit species, among them the seven types of cottontail. The European rabbit, which has been introduced on every continent except Antarctica, is familiar throughout the world as a wild prey animal and as a domesticated form of livestock and pet. With its widespread effect on ecologies and cultures, the rabbit is, in many areas of the world, a part of daily life—as food, clothing, a companion, and a source of artistic inspiration. Although once considered rodents, lagomorphs like rabbits have been discovered to have diverged separately and earlier than their rodent cousins and have a number of traits rodents lack, like two extra incis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, smaller islands. With an area of , Australia is the largest country by area in Oceania and the world's List of countries and dependencies by area, sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a Megadiverse countries, megadiverse country, and its size gives it a wide variety of landscapes and climates, with Deserts of Australia, deserts in the centre, tropical Forests of Australia, rainforests in the north-east, and List of mountains in Australia, mountain ranges in the south-east. The ancestors of Aboriginal Australians began arriving from south east Asia approximately Early human migrations#Nearby Oceania, 65,000 years ago, during the Last Glacial Period, last i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myxomatosis
Myxomatosis is a disease caused by ''Myxoma virus'', a poxvirus in the genus ''Leporipoxvirus''. The natural hosts are tapeti (''Sylvilagus brasiliensis'') in South and Central America, and brush rabbits (''Sylvilagus bachmani'') in North America. The myxoma virus causes only a mild disease in these species, but causes a severe and usually fatal disease in European rabbits (''Oryctolagus cuniculus''). Myxomatosis is an excellent example of what occurs when a virus jumps from a species adapted to it to a naive host, and has been extensively studied for this reason. The virus was intentionally introduced in Australia, France, and Chile in the 1950s to control wild European rabbit populations. Cause ''Myxoma virus'' is in the genus ''Leporipoxvirus'' (family ''Poxviridae''; subfamily ''Chordopoxvirinae''). Like other poxviruses, myxoma viruses are large DNA viruses with linear double-stranded DNA. Virus replication occurs in the cytoplasm of the cell. The natural hosts are tapet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladistics
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics ( synapomorphies'')'' that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms ''worms'' or ''fishes'' were used within a ''strict'' cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically, outside of cladistics, e.g. as a 'grade', which are fruitless to precisely delineate, especially when including extinct species. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East Germany
East Germany, officially the German Democratic Republic (GDR; german: Deutsche Demokratische Republik, , DDR, ), was a country that existed from its creation on 7 October 1949 until its dissolution on 3 October 1990. In these years the state was a part of the Eastern Bloc in the Cold War. Commonly described as a communist state, it described itself as a socialist "workers' and peasants' state".Patrick Major, Jonathan Osmond, ''The Workers' and Peasants' State: Communism and Society in East Germany Under Ulbricht 1945–71'', Manchester University Press, 2002, Its territory was administered and occupied by Soviet forces following the end of World War II—the Soviet occupation zone of the Potsdam Agreement, bounded on the east by the Oder–Neisse line. The Soviet zone surrounded West Berlin but did not include it and West Berlin remained outside the jurisdiction of the GDR. Most scholars and academics describe the GDR as a totalitarian dictatorship. The GDR was establish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Willi Hennig
Emil Hans Willi Hennig (20 April 1913 – 5 November 1976) was a Germans, German biologist and zoologist who is considered the founder of Phylogenesis, phylogenetic systematics, otherwise known as cladistics. In 1945 as a POWs in World War II, prisoner of war, Hennig began work on his theory of cladistics, which he published in German in 1950, with a substantially revised English translation published in 1966. With his works on evolution and systematics he revolutionised the view of the natural order of beings. As a Taxonomy (biology), taxonomist, he specialised in dipterans (true flies). Hennig coined the key terms synapomorphy, Plesiomorphy and symplesiomorphy, symplesiomorphy, and paraphyly. He also asserted, in his "auxiliary principle", that "the presence of apomorphous characters in different species 'is always reason for suspecting kinship [i.e., that species belong to a monophyletic group], and that their origin by convergence should not be presumed a priori' (Hennig, 195 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entomologist
Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arachnids, myriapods, and crustaceans. This wider meaning may still be encountered in informal use. Like several of the other fields that are categorized within zoology, entomology is a taxon-based category; any form of scientific study in which there is a focus on insect-related inquiries is, by definition, entomology. Entomology therefore overlaps with a cross-section of topics as diverse as molecular genetics, behavior, neuroscience, biomechanics, biochemistry, systematics, physiology, developmental biology, ecology, morphology, and paleontology. Over 1.3 million insect species have been described, more than two-thirds of all known species. Some insect species date back to around 400 million years ago. They have many kinds of intera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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