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Spiru Haret
Spiru C. Haret (; 15 February 1851 – 17 December 1912) was a Romanian mathematician, astronomer, and politician. He made a fundamental contribution to the ''n''-body problem in celestial mechanics by proving that using a third degree approximation for the disturbing forces implies instability of the major axes of the orbits, and by introducing the concept of ''secular perturbations'' in relation to this. As a politician, during his three terms as Minister of Education, Haret ran deep reforms, building the modern Romanian education system. He was made a full member of the Romanian Academy in 1892. He also founded the Bucharest Observatory, appointing as its first director. The crater Haret on the Moon is named after him. Life Haret was born in Iași, Moldavia, to Constantin and Smaranda Haret, who were of Armenian origin. His baptismal record listed his name as Spiridon Haret. He started his studies in Dorohoi Iași, and in 1862 moved to Saint Sava High School in Bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iași
Iași ( , , ; also known by other alternative names), also referred to mostly historically as Jassy ( , ), is the second largest city in Romania and the seat of Iași County. Located in the historical region of Moldavia, it has traditionally been one of the leading centres of Romanian social, cultural, academic and artistic life. The city was the capital of the Principality of Moldavia from 1564 to 1859, then of the United Principalities from 1859 to 1862, and the capital of Romania from 1916 to 1918. Known as the Cultural Capital of Romania, Iași is a symbol of Romanian history. Historian Nicolae Iorga stated that "there should be no Romanian who does not know of it". Still referred to as "The Moldavian Capital", Iași is the main economic and business centre of Romania's Moldavian region. In December 2018, Iași was officially declared the Historical Capital of Romania. At the 2011 census, the city-proper had a population of 290,422 (making it the fourth most populous in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Mârzescu
George may refer to: People * George (given name) * George (surname) * George (singer), American-Canadian singer George Nozuka, known by the mononym George * George Washington, First President of the United States * George W. Bush, 43rd President of the United States * George H. W. Bush, 41st President of the United States * George V, King of Great Britain, Ireland, the British Dominions and Emperor of India from 1910-1936 * George VI, King of Great Britain, Ireland, the British Dominions and Emperor of India from 1936-1952 * Prince George of Wales * George Papagheorghe also known as Jorge / GEØRGE * George, stage name of Giorgio Moroder * George Harrison, an English musician and singer-songwriter Places South Africa * George, Western Cape ** George Airport United States * George, Iowa * George, Missouri * George, Washington * George County, Mississippi * George Air Force Base, a former U.S. Air Force base located in California Characters * George (Peppa Pig), a 2-year-old ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semi-major And Semi-minor Axes
In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the longest semidiameter or one half of the major axis, and thus runs from the centre, through a focus, and to the perimeter. The semi-minor axis (minor semiaxis) of an ellipse or hyperbola is a line segment that is at right angles with the semi-major axis and has one end at the center of the conic section. For the special case of a circle, the lengths of the semi-axes are both equal to the radius of the circle. The length of the semi-major axis of an ellipse is related to the semi-minor axis's length through the eccentricity and the semi-latus rectum \ell, as follows: The semi-major axis of a hyperbola is, depending on the convention, plus or minus one half of the distance between the two branches. Thus it is the distance from the center t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orders Of Approximation
In science, engineering, and other quantitative disciplines, order of approximation refers to formal or informal expressions for how accurate an approximation is. Usage in science and engineering In formal expressions, the ordinal number used before the word order refers to the highest power in the series expansion used in the approximation. The expressions: a ''zeroth-order approximation'', a ''first-order approximation'', a ''second-order approximation'', and so forth are used as fixed phrases. The expression a ''zero-order approximation'' is also common. Cardinal numerals are occasionally used in expressions like an ''order-zero approximation'', an ''order-one approximation'', etc. The omission of the word ''order'' leads to phrases that have less formal meaning. Phrases like first approximation or to a first approximation may refer to ''a roughly approximate value of a quantity''. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celestial Mechanics
Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to produce ephemeris data. History Modern analytic celestial mechanics started with Isaac Newton's Principia of 1687. The name "celestial mechanics" is more recent than that. Newton wrote that the field should be called "rational mechanics." The term "dynamics" came in a little later with Gottfried Leibniz, and over a century after Newton, Pierre-Simon Laplace introduced the term "celestial mechanics." Prior to Kepler there was little connection between exact, quantitative prediction of planetary positions, using geometrical or arithmetical techniques, and contemporary discussions of the physical causes of the planets' motion. Johannes Kepler Johannes Kepler (1571–1630) was the first to closely integrate the predictive geom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Politician
A politician is a person active in party politics, or a person holding or seeking an elected office in government. Politicians propose, support, reject and create laws that govern the land and by an extension of its people. Broadly speaking, a politician can be anyone who seeks to achieve political power in a government. Identity Politicians are people who are politically active, especially in party politics. Political positions range from local governments to state governments to federal governments to international governments. All ''government leaders'' are considered politicians. Media and rhetoric Politicians are known for their rhetoric, as in speeches or campaign advertisements. They are especially known for using common themes that allow them to develop their political positions in terms familiar to the voters. Politicians of necessity become expert users of the media. Politicians in the 19th century made heavy use of newspapers, magazines, and pamphlets, as well ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, galaxies – in either observational astronomy, observational (by analyzing the data) or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, Sun, solar astronomy, the Star formation, origin or stellar evolution, evolution of stars, or the galaxy formation and evolution, formation of galaxies. A related but distinct subject is physical cosmology, which studies the Universe as a whole. Types Astronomers usually fall under either of two main types: observational astronomy, observational and theoretical astronomy, theoretical. Observational astronomers make direct observations of Astronomical object, celestial objects and analyze the data. In contrast, theoretical astronomers create and investigate C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History One of the earliest known mathematicians were Thales of Miletus (c. 624–c.546 BC); he has been hailed as the first true mathematician and the first known individual to whom a mathematical discovery has been attributed. He is credited with the first use of deductive reasoning applied to geometry, by deriving four corollaries to Thales' Theorem. The number of known mathematicians grew when Pythagoras of Samos (c. 582–c. 507 BC) established the Pythagorean School, whose doctrine it was that mathematics ruled the universe and whose motto was "All is number". It was the Pythagoreans who coined the term "mathematics", and with whom the study of mathematics for its own sake begins. The first woman mathematician recorded by history was Hypati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gheorghe Grigore Cantacuzino
Prince Gheorghe Grigore Cantacuzino (22 September 1833 – 22 March 1913), was a Romanian politician and lawyer, one of the leading Conservative Party policymakers. Among his political posts were minister of public instruction in Romania, president of the chamber, and president of the senate. He twice served as the Prime Minister of Romania: between 23 April 1899 and 19 July 1900, and between 4 January 1906 and 24 March 1907. He resigned from office after failing to put down the large-scale peasants' revolt. He was the 20th Romanian politician to serve as Prime Minister. The wealthy Cantacuzino was born into the aristocratic Cantacuzino family, of Phanariote origins. He built the Cantacuzino Palace of Bucharest and the Cantacuzino Castle of Bușteni. He was the father of Grigore Gheorghe Cantacuzino and Mihail G. Cantacuzino, as well as the father-in-law of Alexandrina Pallady-Cantacuzino. References External links Biography 1833 births 1913 deaths Gheorghe Gheorghe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ministry Of Internal Affairs (Romania)
The Ministry of Internal Affairs of Romania ( ro, Ministerul Afacerilor Interne) is one of the eighteen ministries of the Government of Romania. From 23 August 1944 to 18 March 1975 the ministry held the title of ''Minister of Internal Affairs'', between 2004 and 2007, held the title of ''Minister of Administration and Interior'', and since April 2007, ''Minister of Interior and Administrative Reform''. In December 2008, the Boc government changed the name back to ''Ministry of Administration and Interior''. Until 2006, the ministry was housed near Lipscani in ''Palatul Vama Poştei'', built between 1914 and 1926 according to the architect Statie Ciortan's plans. In 2006 the ministry moved into the former building of the Senate on Revolution Square. Subordinated structures * Romanian Police * Romanian Inspectorate for Emergency Situations * Romanian Border Police * Romanian Gendarmerie * Romanian National Archives * General Directorate for Intelligence and Internal Securit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constantin Istrati
Constantin I. Istrati (7 September 1850 – 17 January 1919) was a Romanian chemist and physician. He was president of the Romanian Academy between 1913 and 1916. He was born in 1850 in Roman, Moldavia (now in Neamț County, Romania). He studied at the Academia Mihăileană in Iași, after which he went to Bucharest to study at the University of Medicine and Pharmacy, graduating in 1869, and obtaining his M.D. in 1877. After collaborating with Carol Davila, Istrati pursued his studies for three years at the University of Paris, where he obtained in 1885 a Ph.D. in Chemistry under the direction of Charles Adolphe Wurtz and Charles Friedel, with thesis ''On colored ethylbenzene and some observations about boiling points in the aromatic series''. In 1883 he was named Professor of Physics at the School of Bridges and Roads in Bucharest, replacing Emanoil Bacaloglu. On April 1, 1889, Istrati was elected corresponding member of the Romanian Academy. Istrati later became a profe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion I
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons. Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
