George Gamow George Gamow (March 4, 1904- August 19, 1968), born Georgiy Antonovich Gamov, was a Russian-American theoretical physicist and cosmologist. He was an early advocate and developer of Lemaître's Big Bang theory. He discovered a theoretical explanation of alpha decay via quantum tunneling, and worked on radioactive decay of the atomic nucleus, star formation, stellar nucleosynthesis and Big Bang nucleosynthesis (which he collectively called nucleocosmogenesis), and molecular genetics. In his middle and late career, Gamow focused more on teaching and wrote popular books on science, including One Two Three... Early life and career[edit] Gamow was born in Odessa, Russian Empire. He was educated at the Institute of Physics and Mathematics in Odessa[1] (1922–23) and at the University of Leningrad (1923–1929). On graduation, he worked on quantum theory in Göttingen, where his research into the atomic nucleus provided the basis for his doctorate. Bragg Laboratory staff in 1931: W. Defection[edit]
伯特兰·罗素 伯特兰·亚瑟·威廉·罗素，第三代羅素伯爵（英语：Bertrand Arthur William Russell, 3rd Earl Russell，1872年5月18日－1970年2月2日），OM，FRS，英国哲学家、数学家和逻辑学家，致力于哲学的大众化、普及化。[2] 在數學哲學上採取弗雷格的邏輯主義立場，認為數學可以化約到邏輯，哲學可以像邏輯一樣形式系統化，主張逻辑原子論。[3] 1950年，罗素获得诺贝尔文学奖，以表彰其“西歐思想，言論自由最勇敢的君子，卓越的活力，勇氣，智慧與感受性，代表了諾貝爾獎的原意和精神”。 1921年罗素曾於中国讲学，对中国学术界有相当影响。 生平[编辑] 他出生于1872年，當時大英帝国正值巅峰，逝于1970年，此时英国经历過两次世界大战，其帝國已經沒落。 罗素出生于英国威尔士的一个贵族家庭，祖父约翰·罗素勋爵在1840年代曾两次出任英国首相，父亲安伯雷子爵（Viscount Amberley）是一名无神论者。 在双亲去世后，罗素和他的哥哥富兰克·罗素（未来的第二代罗素伯爵）就由祖父母抚养长大。 1890年罗素进入剑桥大学三一学院学习哲学、逻辑学和数学，1908年成为学院的研究员并获选为英国皇家学会院士。 1921年，罗素与前妻离婚后与荳拉·勃拉克（Dora Black）结婚，他们育有两个孩子。 当徐志摩远赴英伦想拜罗素为师的时候，罗素已经离开剑桥大学。 1931年罗素的哥哥去世，罗素继承爵位，成为第三代罗素伯爵。 罗素和荳拉·勃拉克也很快因勃拉克部分報復性地与一个美国记者的一段婚外情暴露而告终。 1952年罗素再度离婚，和一名美国的英语教授结婚。 思想与贡献[编辑] 罗素起初对数学感兴趣，后来逐渐转向哲学方面，他在数学方面也有很多重要的建树。 哲学上罗素最大的贡献是和喬治·愛德華·摩爾、弗雷格、维特根斯坦和怀特海一起创立了逻辑分析哲学，此外他还在认识论、形而上学、伦理学、政治哲学和哲学史方面做出过贡献。 罗素的分析哲学由此诞生：通过将哲学问题转化为逻辑符号，哲学家们就能够更容易地推导出结果，而不会被不够严谨的语言所误导。 20世纪初转向逻辑实证主义，提出逻辑原子论，要求从相当于逻辑上原始命题的原始事实出发，以这种事实作基本元素，由此构造出整个世界。 之后，罗素的注意力转向其他较世俗性的事务。 和平运动[编辑] 罗素曾经说：「我绝不会为了我的信仰而献身，因为我可能是错的。」
Interpretations of quantum mechanics Area of physical and philosophical debate An interpretation of quantum mechanics is an attempt to explain how the mathematical theory of quantum mechanics might correspond to experienced reality. Although quantum mechanics has held up to rigorous and extremely precise tests in an extraordinarily broad range of experiments, there exist a number of contending schools of thought over their interpretation. Despite nearly a century of debate and experiment, no consensus has been reached among physicists and philosophers of physics concerning which interpretation best "represents" reality.[1][2] Examples of different interpretations include the Copenhagen interpretation, the Many-worlds interpretation, QBism, and de Broglie–Bohm theory. History[edit] The definition of quantum theorists' terms, such as wave function and matrix mechanics, progressed through many stages. The physicist N. Nature[edit] More or less, all interpretations of quantum mechanics share two qualities: Many worlds[edit]
Martin Ryle Sir Martin Ryle FRS[3] (27 September 1918 – 14 October 1984) was an English radio astronomer who developed revolutionary radio telescope systems (see e.g. aperture synthesis) and used them for accurate location and imaging of weak radio sources. In 1946 Ryle and Derek Vonberg were the first people to publish interferometric astronomical measurements at radio wavelengths. With improved equipment, Ryle observed the most distant known galaxies in the universe at that time. He was the first Professor of Radio Astronomy at the University of Cambridge, and founding director of the Mullard Radio Astronomy Observatory. He was Astronomer Royal from 1972 to 1982.[4] Ryle and Antony Hewish shared the Nobel Prize for Physics in 1974, the first Nobel prize awarded in recognition of astronomical research.[5] In the 1970s, Ryle turned the greater part of his attention from astronomy to social and political issues which he considered to be more urgent. Education and early life[edit] Personality[edit]
Bertrand Russell Russell led the British "revolt against idealism" in the early 20th century.[58] He is considered one of the founders of analytic philosophy along with his predecessor Gottlob Frege, colleague G. E. Moore, and his protégé Ludwig Wittgenstein. Russell was a prominent anti-war activist; he championed anti-imperialism[60][61] and went to prison for his pacifism during World War I.[62] Later, he campaigned against Adolf Hitler, then criticised Stalinist totalitarianism, attacked the involvement of the United States in the Vietnam War, and was an outspoken proponent of nuclear disarmament.[63] In 1950 Russell was awarded the Nobel Prize in Literature "in recognition of his varied and significant writings in which he champions humanitarian ideals and freedom of thought Biography Early life and background Young Bertrand Russell Childhood and adolescence Russell had two siblings: brother Frank (nearly seven years older than Bertrand), and sister Rachel (four years older). Early career
Wave function collapse Process by which a quantum system takes on a definitive state Calculations of quantum decoherence show that when a quantum system interacts with the environment, the superpositions apparently reduce to mixtures of classical alternatives. Significantly, the combined wave function of the system and environment continue to obey the Schrödinger equation throughout this apparent collapse.[4] More importantly, this is not enough to explain actual wave function collapse, as decoherence does not reduce it to a single eigenstate.[2][5] Historically, Werner Heisenberg was the first to use the idea of wave function reduction to explain quantum measurement.[6] Mathematical description[edit] Mathematical background[edit] The quantum state of a physical system is described by a wave function (in turn—an element of a projective Hilbert space). The kets where represents the Kronecker delta. , of the observable. and the momentum of (say) a particle, but also its energy components of spin ( ), orbital ( . , that is
Finsler manifold In mathematics, particularly differential geometry, a Finsler manifold is a differentiable manifold M where a (possibly asymmetric) Minkowski norm F(x, −) is provided on each tangent space TxM, that enables one to define the length of any smooth curve γ : [a, b] → M as Finsler manifolds are more general than Riemannian manifolds since the tangent norms need not be induced by inner products. Every Finsler manifold becomes an intrinsic quasimetric space when the distance between two points is defined as the infimum length of the curves that join them. Élie Cartan (1933) named Finsler manifolds after Paul Finsler, who studied this geometry in his dissertation (Finsler 1918). Definition[edit] A Finsler manifold is a differentiable manifold M together with a Finsler metric, which is a continuous nonnegative function F: TM → [0, +∞) defined on the tangent bundle so that for each point x of M, In other words, F(x, −) is an asymmetric norm on each tangent space TxM. Examples[edit] Let where Notes[edit]
Penrhyndeudraeth - Wikipedia Penrhyndeudraeth[pronunciation?] (English: "peninsula with two beaches") is a small town in the Welsh county of Gwynedd. The town is close to the mouth of the River Dwyryd on the A487 nearly 3 miles (4.8 km) east of Porthmadog, and had a population of 2,150 at the 2011 census,[1] increased from 2,031 in 2001.[2] History[edit] The lower half of Penrhyndeudraeth used to be a lake, which was then drained to create the area where the village's High Street is today. Castell Deudraeth, Penrhyndeudraeth NLW3362103 Halfway between Penrhyndeudraeth and Minffordd, next to the Snowdonia National Park Headquarters, but standing apart, is Hendre Hall, where in 1648 Humphrey Humphreys was born. The property named "Cae Ednyfed", between Penrhyndeudraeth and Minffordd, was once the property of Ednyfed Fychan, commander-in-chief to Llywelyn ap Iorwerth. The town was originally in two parishes, Llanfrothen and Llandecwyn, before a new parish was created in 1859. Governance[edit] Industry[edit] Transport[edit]
Sodium/potassium/calcium exchanger 5 Sodium/potassium/calcium exchanger 5 (NCKX5), also known as solute carrier family 24 member 5 (SLC24A5), is a protein that in humans is encoded by the SLC24A5 gene that has a major influence on natural skin colour variation.[5] The NCKX5 protein is a member of the potassium-dependent sodium/calcium exchanger family. Sequence variation in the SLC24A5 gene, particularly a non-synonymous SNP changing the amino acid at position 111 in NCKX5 from alanine to threonine, has been associated with differences in skin pigmentation.[6] The SLC24A5 gene's derived threonine or Ala111Thr allele (rs1426654[7]) has been shown to be a major factor in the light skin tone of Europeans compared to Sub-Saharan Africans, and is believed to represent as much as 25–40% of the average skin tone difference between Europeans and West Africans.[5][8] It has been the subject of recent selection in Europe, and is fixed in European populations.[9][10][11] Gene[edit] Protein[edit] Effect on skin color[edit] See also[edit]
Non-Euclidean geometry Behavior of lines with a common perpendicular in each of the three types of geometry In mathematics, non-Euclidean geometry consists of two geometries based on axioms closely related to those specifying Euclidean geometry. As Euclidean geometry lies at the intersection of metric geometry and affine geometry, non-Euclidean geometry arises when either the metric requirement is relaxed, or the parallel postulate is set aside. In the latter case one obtains hyperbolic geometry and elliptic geometry, the traditional non-Euclidean geometries. Another way to describe the differences between these geometries is to consider two straight lines indefinitely extended in a two-dimensional plane that are both perpendicular to a third line: History[edit] Early history[edit] While Euclidean geometry, named after the Greek mathematician Euclid, includes some of the oldest known mathematics, non-Euclidean geometries were not widely accepted as legitimate until the 19th century. Terminology[edit]
Bertrand Russell Bertrand Arthur William Russell was born at Trelleck on 18th May, 1872. His parents were Viscount Amberley and Katherine, daughter of 2nd Baron Stanley of Alderley. At the age of three he was left an orphan. His father had wished him to be brought up as an agnostic; to avoid this he was made a ward of Court, and brought up by his grandmother. Instead of being sent to school he was taught by governesses and tutors, and thus acquired a perfect knowledge of French and German. In December 1894 he married Miss Alys Pearsall Smith. In 1920 Russell had paid a short visit to Russia to study the conditions of Bolshevism on the spot. Russell was elected a fellow of the Royal Society in 1908, and re-elected a fellow of Trinity College in 1944. In a paper "Logical Atomism" (Contemporary British Philosophy. 1) The matter for this sketch is taken from general English reference books. From Les Prix Nobel en 1950, Editor Arne Holmberg, [Nobel Foundation], Stockholm, 1951
Rebound effect (conservation) Increase in consumption following energy or resource savings Super conservation (RE < 0): the actual resource savings are higher than expected savings – the rebound effect is negative.Zero rebound (RE = 0): The actual resource savings are equal to expected savings – the rebound effect is zero.Partial rebound (0 < RE < 1): The actual resource savings are less than expected savings – the rebound effect is between 0% and 100%. This is sometimes known as 'take-back', and is the most common result of empirical studies on individual markets.Full rebound (RE = 1): The actual resource savings are equal to the increase in usage – the rebound effect is at 100%.Backfire (RE > 1): The actual resource savings are negative because usage increased beyond potential savings – the rebound effect is higher than 100%. This work provided a theoretical grounding for empirical studies and played an important role in defining the problem of the rebound effect. Direct and Indirect Effects
Riemannian geometry Riemannian geometry is the branch of differential geometry that studies Riemannian manifolds, smooth manifolds with a Riemannian metric, i.e. with an inner product on the tangent space at each point that varies smoothly from point to point. This gives, in particular, local notions of angle, length of curves, surface area and volume. From those, some other global quantities can be derived by integrating local contributions. Riemannian geometry originated with the vision of Bernhard Riemann expressed in his inaugural lecture "Ueber die Hypothesen, welche der Geometrie zu Grunde liegen" ("On the Hypotheses on which Geometry is Based"). Introduction[edit] Every smooth manifold admits a Riemannian metric, which often helps to solve problems of differential topology. There exists a close analogy of differential geometry with the mathematical structure of defects in regular crystals. The following articles provide some useful introductory material: Classical theorems[edit] General theorems[edit]