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N. A. Belcourt
N is the fourteenth letter of the Latin alphabet. N or n may also refer to: Mathematics * \mathbb, the set of natural numbers * N, the field norm * N for ''nullae'', a rare Roman numeral for zero * n, the size of a statistical sample Science * N for Newton (unit), the SI derived unit of force * N or F_n, a normal force in mechanics * Nitrogen, symbol N, a chemical element * N or Asn, the symbol for the common natural amino acid asparagine * N, the Normality (chemistry) or chemical concentration of a solution * ''N'', the neutron number, the number of neutrons in a nuclide * N, in Brillouin zone, the center of a face of a body-centered cubic lattice * n, for nano-, prefix in the SI system of units denoting a factor of 10−9 * n, the optical refractive index of a material * n, the principal quantum number, the first of a set of quantum numbers of an atomic orbital * n, an electron density, the measure of the probability of an electron being present at a specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notability
Notability is the property of being worthy of notice, having fame, or being considered to be of a high degree of interest, significance, or distinction. It also refers to the capacity to be such. Persons who are notable due to public responsibility, accomplishments, or, even, mere participation in the celebrity industry are said to have a public profile. The concept arises in the philosophy of aesthetics regarding aesthetic appraisal.Aesthetic Appraisal', Philosophy (1975), 50: 189–204, Evan Simpson There are criticisms of art galleries determining monetary valuation, or valuation so as to determine what or what not to display, being based on notability of the artist, rather than inherent quality of the art work. Notability arises in decisions on coverage questions in journalism. Marketers and newspapers may try to create notability to create celebrity, fame, or notoriety, or to increase sales, as in the yellow press. The privileged class are sometimes called notables, when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Number
In chemistry, crystallography, and materials science, the coordination number, also called ligancy, of a central atom in a molecule or crystal is the number of atoms, molecules or ions bonded to it. The ion/molecule/atom surrounding the central ion/molecule/atom is called a ligand. This number is determined somewhat differently for molecules than for crystals. For molecules and polyatomic ions the coordination number of an atom is determined by simply counting the other atoms to which it is bonded (by either single or multiple bonds). For example, r(NH3)2Cl2Br2sup>− has Cr3+ as its central cation, which has a coordination number of 6 and is described as ''hexacoordinate''. The common coordination numbers are 4, 6 and 8. Molecules, polyatomic ions and coordination complexes In chemistry, coordination number, defined originally in 1893 by Alfred Werner, is the total number of neighbors of a central atom in a molecule or ion. The concept is most commonly applied to coordin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N (Poland)
n was a Polish DTH platform. It was launched on October 12, 2006 and owned by ITI Neovision. On December 31, 2011 the company had reached 929,000 subscribers. On March 21, 2013, n was merged with Cyfra+ to form nc+. History In May 2006, the ITI Group announced the opening of a "new generation" subscription television platform for the autumn of 2006, with TVN and Onet acting as key strategic partners in the upcoming project. N was unveiled to the public in September 2006, aiming for an October 12 launch date. Channels At closing time, N had 99 encrypted channels (6 in foreign languages), 23 free-to-air channels in Polish, 34 HDTV channels, and 3 3D channels. In-house channels Throughout its history, N also had its own in-house channels: *Wojna i Pokój (War and Peace): The channel broadcast movies from the Soviet Union and contemporary Russia, with either Polish voice-over or original Russian audio. Converted to HD in 2012, after which the channel timeshared with Sundance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthing System
An earthing system (UK and IEC) or grounding system (US) connects specific parts of an electric power system with the ground, typically the Earth's conductive surface, for safety and functional purposes. The choice of earthing system can affect the safety and electromagnetic compatibility of the installation. Regulations for earthing systems vary among countries, though most follow the recommendations of the International Electrotechnical Commission (IEC). Regulations may identify special cases for earthing in mines, in patient care areas, or in hazardous areas of industrial plants. In addition to electric power systems, other systems may require grounding for safety or function. Tall structures may have lightning rods as part of a system to protect them from lightning strikes. Telegraph lines may use the Earth as one conductor of a circuit, saving the cost of installation of a return wire over a long circuit. Radio antennas may require particular grounding for operation, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Penetration Test
The standard penetration test (SPT) is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil. This test is the most frequently used subsurface exploration drilling test performed worldwide. The test procedure is described in ISO 22476-3, ASTM D1586 and Australian Standards AS 1289.6.3.1. The test provides samples for identification purposes and provides a measure of penetration resistance which can be used for geotechnical design purposes. Many local and widely published international correlations which relate blow count, or N-value, to the engineering properties of soils are available for geotechnical engineering purposes. Procedure The test uses a thick-walled sampling tube, with an outside diameter of 5.08 cm and an inside diameter of 3.5 cm, and a length of around 65 cm. The sampling tube is driven into the ground at the bottom of a borehole by blows from a slide hammer with a mass of 63.5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vagus Nerve
The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right vagus nerves—but they are typically referred to collectively as a single subsystem. The vagus is the longest nerve of the autonomic nervous system in the human body and comprises both sensory and motor fibers. The sensory fibers originate from neurons of the nodose ganglion, whereas the motor fibers come from neurons of the dorsal motor nucleus of the vagus and the nucleus ambiguus. The vagus was also historically called the pneumogastric nerve. Structure Upon leaving the medulla oblongata between the olive and the inferior cerebellar peduncle, the vagus nerve extends through the jugular foramen, then passes into the carotid sheath between the internal carotid artery and the internal jugular vein down to the neck, chest, and abdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerve
A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called action potentials that are transmitted along each of the axons to peripheral organs or, in the case of sensory nerves, from the periphery back to the central nervous system. Each axon, within the nerve, is an extension of an individual neuron, along with other supportive cells such as some Schwann cells that coat the axons in myelin. Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium. The axons are bundled together into groups called fascicles, and each fascicle is wrapped in a layer of connective tissue called the perineurium. Finally, the entire nerve is wrapped in a layer of connective tissue called the epineurium. Nerve cells (often called neurons) are f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N Ray
N-rays (or N rays) were a hypothesized form of radiation, described by French physicist Prosper-René Blondlot in 1903, and initially confirmed by others, but subsequently found to be illusory. History Context The N-ray affair occurred shortly after a series of major breakthroughs in experimental physics. Victor Schumann discovered vacuum ultraviolet radiation in 1893, Wilhelm Röntgen discovered X-rays in 1895, Henri Becquerel discovered radioactivity in 1896, and, in 1897, J. J. Thomson discovered electrons, showing that they were the constituents of cathode rays. This created an expectation within the scientific community that other forms of radiation might be discovered. At this time, Prosper-René Blondlot was a professor of physics at the University of Nancy studying electromagnetic radiation. Blondlot was a respected member of the scientific community: he was one of eight physicists who were corresponding members of the French Academy of Sciences and was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N Band
N, or n, is the fourteenth letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''en'' (pronounced ), plural ''ens''. History One of the most common hieroglyphs, snake, was used in Egyptian writing to stand for a sound like the English , because the Egyptian word for "snake" was ''djet''. It is speculated by many that Semitic people working in Egypt adapted hieroglyphics to create the first alphabet, and that they used the same snake symbol to represent N, because their word for "snake" may have begun with that sound. However, the name for the letter in the Phoenician, Hebrew, Aramaic and Arabic alphabets is ''nun'', which means "fish" in some of these languages. The sound value of the letter was —as in Greek, Etruscan, Latin and modern languages. Use in writing systems represents a dental or alveolar nasal in virtually all languages that use the Latin alp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplogroup N (Y-DNA)
Haplogroup N (M231) is a Y-chromosome DNA haplogroup defined by the presence of the single-nucleotide polymorphism (SNP) marker M231. It is most commonly found in males originating from northern Eurasia. It also has been observed at lower frequencies in populations native to other regions, including parts of the Balkans, Central Asia, East Asia, and Southeast Asia. Origins Haplogroup NO-M214 – its most recent common ancestor with its sibling, haplogroup O-M175 – is estimated to have existed about 36,800–44,700 years ago.YFull Haplogroup YTree v6.05.11 at 25 September 2018. It is generally considered that N-M231 arose in approximately 19,400 (±4,80 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplogroup N (mtDNA)
Haplogroup N is a human mitochondrial DNA (mtDNA) clade. A macrohaplogroup, its descendant lineages are distributed across many continents. Like its sibling macrohaplogroup M, macrohaplogroup N is a descendant of the haplogroup L3. All mtDNA haplogroups found outside of Africa are descendants of either haplogroup N or its sibling haplogroup M. M and N are the signature maternal haplogroups that define the theory of the recent African origin of modern humans and subsequent early human migrations around the world. The global distribution of haplogroups N and M indicates that there was likely at least one major prehistoric migration of humans out of Africa, with both N and M later evolving outside the continent. Origins There is widespread agreement in the scientific community concerning the African ancestry of haplogroup L3 (haplogroup N's parent clade). However, whether or not the mutations which define haplogroup N itself first occurred within Asia or Africa has been a subject ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
