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1908 In Science
The year 1908 in science and technology involved some significant events, listed below. Archaeology * A 40,000-year-old Neanderthal boy skeleton is found at Le Moustier in southwest France by Otto Hauser. Astronomy * If its start and end are defined using mean solar time then due to the extreme length of day variation this is the longest year of the Julian calendar or Gregorian calendar, having a duration of 31622401.38 seconds of Terrestrial Time (or ephemeris time). * – Tunguska event in Siberia, an explosion believed to have been caused by the air burst of a large meteoroid or comet fragment at an altitude of above the Earth's surface. Chemistry * Kikunae Ikeda discovers monosodium glutamate, the chemical behind the taste of umami. * Heike Kamerlingh Onnes liquefies helium. Genetics * G. H. Hardy and Wilhelm Weinberg independently formulate the Hardy–Weinberg principle which states that both allele and genotype frequencies in a population remain in equilibrium unless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for scientific reasoning is tens of thousands of years old. The earliest written records in the history of science come from Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age and later by the efforts of Byzantine Greek scholars who brought Greek ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteoroid
A meteoroid () is a small rocky or metallic body in outer space. Meteoroids are defined as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than this are classified as micrometeoroids or space dust. Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars. When a meteoroid, comet, or asteroid enters Earth's atmosphere at a speed typically in excess of , aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor or "shooting star". Meteors typically become visible when they are about 100 km above sea level. A series of many meteors appearing seconds or minutes apart and appearing to originate from the same fixed point in the sky is called a meteor shower. A meteorite is the remains of a meteoroid th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genotype Frequency
Genetic variation in populations can be analyzed and quantified by the frequency of alleles. Two fundamental calculations are central to population genetics: allele frequencies and genotype frequencies. Genotype frequency in a population is the number of individuals with a given genotype divided by the total number of individuals in the population. In population genetics, the genotype frequency is the frequency or proportion (i.e., 0 < ''f'' < 1) of genotypes in a population. Although allele and genotype frequencies are related, it is important to clearly distinguish them. Genotype frequency may also be used in the future (for "genomic profiling") to predict someone's having a disease or even a birth defect. It can also be used to determine ethnic diversity. Genotype frequencies may be represented by a . Numerical ...
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Allele Frequency
Allele frequency, or gene frequency, is the relative frequency of an allele (variant of a gene) at a particular locus in a population, expressed as a fraction or percentage. Specifically, it is the fraction of all chromosomes in the population that carry that allele over the total population or sample size. Microevolution is the change in allele frequencies that occurs over time within a population. Given the following: # A particular locus on a chromosome and a given allele at that locus # A population of ''N'' individuals with ploidy ''n'', i.e. an individual carries ''n'' copies of each chromosome in their somatic cells (e.g. two chromosomes in the cells of diploid species) # The allele exists in ''i'' chromosomes in the population then the allele frequency is the fraction of all the occurrences ''i'' of that allele and the total number of chromosome copies across the population, ''i''/(''nN''). The allele frequency is distinct from the genotype frequency, although they are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardy–Weinberg Principle
In population genetics, the Hardy–Weinberg principle, also known as the Hardy–Weinberg equilibrium, model, theorem, or law, states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. These influences include ''genetic drift'', '' mate choice'', ''assortative mating'', ''natural selection'', ''sexual selection'', ''mutation'', '' gene flow'', ''meiotic drive'', ''genetic hitchhiking'', '' population bottleneck'', '' founder effect,'' ''inbreeding and outbreeding depression''. In the simplest case of a single locus with two alleles denoted ''A'' and ''a'' with frequencies and , respectively, the expected genotype frequencies under random mating are for the AA homozygotes, for the aa homozygotes, and for the heterozygotes. In the absence of selection, mutation, genetic drift, or other forces, allele frequencies ''p'' and ''q'' are constant between generations, so equilibri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Weinberg
Wilhelm Weinberg (Stuttgart, 25 December 1862 – 27 November 1937, Tübingen) was a German obstetrician-gynecologist, practicing in Stuttgart, who in a 1908 paper, published in German in ''Jahresheft des Vereins für vaterländische Naturkunde in Württemberg'' (The Annals of the Society of National Natural History in Württemberg), expressed the concept that would later come to be known as the Hardy–Weinberg principle. Weinberg is also credited as the first to explain the effect of ascertainment bias on observations in genetics. Hardy–Weinberg principle Weinberg developed the principle of genetic equilibrium independently of British mathematician G.H. Hardy. He delivered an exposition of his ideas in a lecture on January 13, 1908, before the ''Verein für vaterländische Naturkunde in Württemberg'' (Society for the Natural History of the Fatherland in Württemberg), about three months before the Hardy's notes from April 1908 of that year and five months before Hardy' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling and melting point are the lowest among all the elements. It is the second lightest and second most abundant element in the observable universe (hydrogen is the lightest and most abundant). It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and in Jupiter, due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, the vast majority of which was formed during t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heike Kamerlingh Onnes
Heike Kamerlingh Onnes (21 September 1853 – 21 February 1926) was a Dutch physicist and Nobel laureate. He exploited the Hampson–Linde cycle to investigate how materials behave when cooled to nearly absolute zero and later to liquefy helium for the first time, in 1908. He also discovered superconductivity in 1911. Biography Early years Kamerlingh Onnes was born in Groningen, Netherlands. His father, Harm Kamerlingh Onnes, was a brickworks owner. His mother was Anna Gerdina Coers of Arnhem. In 1870, Kamerlingh Onnes attended the University of Groningen. He studied under Robert Bunsen and Gustav Kirchhoff at the University of Heidelberg from 1871 to 1873. Again at Groningen, he obtained his master's degree in 1878 and a doctorate in 1879. His thesis was ''Nieuwe bewijzen voor de aswenteling der aarde'' (''tr''. New proofs of the rotation of the earth). From 1878 to 1882 he was assistant to Johannes Bosscha, the director of the Delft Polytechnic, for whom he substituted as lec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umami
Umami ( from ja, 旨味 ), or savoriness, is one of the five basic tastes. It has been described as savory and is characteristic of broths and cooked meats. People taste umami through taste receptors that typically respond to glutamates and nucleotides, which are widely present in meat broths and fermented products. Glutamates are commonly added to some foods in the form of monosodium glutamate (MSG), and nucleotides are commonly added in the form of disodium guanylate, inosine monophosphate (IMP) or guanosine monophosphate (GMP). Since umami has its own receptors rather than arising out of a combination of the traditionally recognized taste receptors, scientists now consider umami to be a distinct taste. Foods that have a strong umami flavor include meats, shellfish, fish (including fish sauce and preserved fish such as maldive fish, '' Katsuobushi'', sardines, and anchovies), tomatoes, mushrooms, hydrolyzed vegetable protein, meat extract, yeast extract, cheeses, and soy s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monosodium Glutamate
Monosodium glutamate (MSG), also known as sodium glutamate, is the sodium salt of glutamic acid. MSG is found naturally in some foods including tomatoes and cheese in this glutamic acid form. MSG is used in cooking as a flavor enhancer with an umami taste that intensifies the meaty, savory flavor of food, as naturally occurring glutamate does in foods such as stews and meat soups. MSG was first prepared in 1908 by Japanese biochemist Kikunae Ikeda, who was trying to isolate and duplicate the savory taste of ''kombu'', an edible seaweed used as a base for many Japanese soups. MSG balances, blends, and rounds the perception of other tastes. MSG is commonly used and found in stock (bouillon) cubes, soups, ramen, gravy, stews, condiments, savory snacks, etc. The U.S. Food and Drug Administration has given MSG its generally recognized as safe (GRAS) designation. It is a popular belief that MSG can cause headaches and other feelings of discomfort, known as "Chinese resta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kikunae Ikeda
was a Japanese chemist and Tokyo Imperial University professor of chemistry who, in 1908, uncovered the chemical basis of a taste he named umami. It is one of the five basic tastes along with sweet, bitter, sour and salty. Ikeda graduated in 1889 from Tokyo Imperial University in chemistry. In 1891, he became a professor at the Higher Normal School of Tokyo, in 1896 he became an associate professor at Tokyo Imperial University. From 1899, Prof. Ikeda studied in Germany for two years at the laboratory of Prof. Friedrich Wilhelm Ostwald at the University of Leipzig, which was then the center of physical chemistry. After a brief stay in London, he returned to Tokyo in 1901 and became a full professor in chemistry at Tokyo Imperial University. In 1907 at the Tokyo Imperial University in Japan, Ikeda was eating dinner with his family when he suddenly stopped. That day the dashi broth in his soup was more delicious than normal; after stirring a few times he realized the difference wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Observatory (journal)
''The Observatory'' is a publication, variously described as a journal, a magazine and a review, devoted to astronomy. It appeared regularly starting in 1877, and it is now published every two months. The current editors are David Stickland, Bob Argyle and Steve Fossey. Although it is not published by the Royal Astronomical Society, it publishes the reports of its meetings. Other features are the extensive book reviews and "Here and There", a collection of misprints and ridiculous statements of astronomical interest. The founder and first editor (1877–1882) was William Christie, then chief assistant at the Royal Observatory and later Astronomer Royal. Notable subsequent editors include: * Arthur Eddington (1913–1919) * Harold Spencer Jones (1915–1923) * Richard van der Riet Woolley (1933–1939) * William McCrea (1935–1937) * Margaret Burbidge (1948–1951) * Antony Hewish (1957–1961) * Donald Lynden-Bell (1967–1969) * Carole Jordan (1968–1973) * Jocelyn Bel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
