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Neanderthals In Southwest Asia
Southwest Asian Neanderthals were Neanderthals who lived in Turkey, Lebanon, Syria, Palestine, Israel, Iraq, and Iran - the southernmost expanse of the known Neanderthal range. Although their arrival in Asia is not well-dated, early Neanderthals occupied the region apparently until about 100,000 years ago. At this time, ''Homo sapiens'' immigrants seem to have replaced them in one of the first anatomically-modern expansions out of Africa. In their turn, starting around 80,000 years ago, Neanderthals seem to have returned and replaced ''Homo sapiens'' in Southwest Asia. They inhabited the region until about 55,000 years ago. In Southwest Asia Neanderthals have left well-preserved skeletal remains in present-day Israel, Syria, and Iraq. Remains in Turkey, Lebanon, and Iran are fragmentary. No Neanderthal skeletal remains have ever been found to the south of Jerusalem, and although there are Middle Palaeolithic Levallois points in Jordan and in the Arabian peninsula, it is unclear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Range Of Neanderthals In The Levant
Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to identify a survey township in the US * Rangeland, deserts, grasslands, shrublands, wetlands, and woodlands that are grazed by domestic livestock or wild animals Mathematics * Range of a function, a set containing the output values produced by a function * Range (statistics), the difference between the highest and the lowest values in a set * Interval (mathematics), also called ''range'', a set of real numbers that includes all numbers between any two numbers in the set * Column space, also called the ''range'' of a matrix, is the set of all possible linear combinations of the column vectors of the matrix * Projective range, a line or a conic in projective geometry * Range of a quantifier, in logic Music * Range (music), the distance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C4 Carbon Fixation
carbon fixation or the Hatch–Slack pathway is one of three known photosynthetic processes of carbon fixation in plants. It owes the names to the 1960's discovery by Marshall Davidson Hatch and Charles Roger Slack that some plants, when supplied with 14, incorporate the 14C label into four-carbon molecules first. fixation is an addition to the ancestral and more common carbon fixation. The main carboxylating enzyme in photosynthesis is called RuBisCO, which catalyses two distinct reactions using either (carboxylation) or oxygen (oxygenation) as a substrate. The latter process, oxygenation, gives rise to the wasteful process of photorespiration. photosynthesis reduces photorespiration by concentrating around RuBisCO. To ensure that RuBisCO works in an environment where there is a lot of carbon dioxide and very little oxygen, leaves generally differentiate two partially isolated compartments called mesophyll cells and bundle-sheath cells. is initially fixed in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Origins Of Us
''Origins of Us'' is a British television series documentary series shown on BBC Two. It is about human evolution and is presented by Alice Roberts. It consists of three episodes, each an hour long. * Episode 1: air date 17 October 2011 – Bones * Episode 2: air date 24 October 2011 – Guts * Episode 3: air date 31 October 2011 – Brains See also * ''Dawn of Humanity'' (2015 PBS documentary) * ''Prehistoric Autopsy'' (2012 BBC documentary) * ''The Incredible Human Journey'' (2009 BBC documentary) * The Origins of Us told honestly References External link * . * ''Origins of Us''aDocuWiki.net * ''Origins of Us''at Amazon. ''Origins of Us''– video search on YouTube. ''Origins of Us''– video search on Dailymotion. * Human Timeline (Interactive)– Smithsonian, National Museum of Natural History The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gibraltar Neanderthals
The Neanderthals in Gibraltar were among the first to be discovered by modern scientists and have been among the most well studied of their species according to a number of extinction studies which emphasize regional differences, usually claiming the Iberian Peninsula partially acted as a “refuge” for the shrinking Neanderthal populations and the Gibraltar population of Neanderthals as having been one of many dwindling populations of archaic human populations, existing just until around 42,000 years ago. Many other Neanderthal populations went extinct around the same time. The skull of a Neanderthal woman, discovered in a quarry in 1848, was only the second Neanderthal skull ever found and the first adult Neanderthal skull to be discovered, eight years before the discovery of the skull for which the species was named in Neandertal, Germany; had it been recognised as a separate species, it might have been called Calpican (or Gibraltarian) rather than Neanderthal Man. The sku ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dawn Of Humanity (film)
''Dawn of Humanity'' is a 2015 American documentary film that was released online on September 10, 2015, and aired nationwide in the United States on September 16, 2015. The PBS NOVA National Geographic film, in one episode of two hours, was directed and produced by Graham Townsley. The film describes the 2013 discovery, and later excavation, of the fossil remains of ''Homo naledi'', an extinct species of hominin assigned to the genus ''Homo'', found within the Dinaledi Chamber of the Rising Star Cave system, located in the Cradle of Humankind, South Africa. Additionally, the National Geographic Society has multiple videos on its website covering different phases of the discovery and excavation of the fossils during a two-year period. , fossils of at least fifteen individuals, amounting to 1550 specimens, have been excavated from the cave. Participants The documentary film is narrated by Jay O. Sanders and includes the following participants (alphabetized by last name): * Reb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen-16
Oxygen-16 (16O) is a stable isotope of oxygen, having 8 neutrons and 8 protons in its nucleus. It has a mass of . Oxygen-16 is the most abundant isotope of oxygen and accounts for 99.762% of oxygen's natural abundance. The relative and absolute abundance of 16O are high because it is a principal product of stellar evolution and because it is a primordial isotope, meaning it can be made by stars that were initially made exclusively of hydrogen. Most 16O is synthesized at the end of the helium fusion process in stars; the triple-alpha process creates 12C, which captures an additional 4He to make 16O. The neon-burning process creates additional 16O. Oxygen-16 is doubly magic. Solid samples (organic and inorganic) for 16O studies are usually stored in silver cups and measured with pyrolysis and mass spectrometry. Researchers need to avoid improper or prolonged storage of the samples for accurate measurements. Oxygen-16 was originally the standard from which the atomic masses of al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon-12
Carbon-12 (12C) is the most abundant of the two stable isotopes of carbon (carbon-13 being the other), amounting to 98.93% of element carbon on Earth; its abundance is due to the triple-alpha process by which it is created in stars. Carbon-12 is of particular importance in its use as the standard from which atomic masses of all nuclides are measured, thus, its atomic mass is exactly 12 daltons by definition. Carbon-12 is composed of 6 protons, 6 neutrons, and 6 electrons. History Before 1959, both the IUPAP and IUPAC used oxygen to define the mole; the chemists defining the mole as the number of atoms of oxygen which had mass 16 g, the physicists using a similar definition but with the oxygen-16 isotope only. The two organizations agreed in 1959/60 to define the mole as follows. ''Mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 12 gram of carbon 12; its symbol is "mol".'' This was adopted by the CIPM (Inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isotopes
Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) due to different numbers of neutrons in their nuclei. While all isotopes of a given element have almost the same chemical properties, they have different atomic masses and physical properties. The term isotope is formed from the Greek roots isos ( ἴσος "equal") and topos ( τόπος "place"), meaning "the same place"; thus, the meaning behind the name is that different isotopes of a single element occupy the same position on the periodic table. It was coined by Scottish doctor and writer Margaret Todd in 1913 in a suggestion to the British chemist Frederick Soddy. The number of protons within the atom's nucleus is called its atomic number and is equal to the number of electrons in the neutral (non-ionized) atom. Each atomic numbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen-18
Oxygen-18 (, Ω) is a natural, stable isotope of oxygen and one of the environmental isotopes. is an important precursor for the production of fluorodeoxyglucose (FDG) used in positron emission tomography (PET). Generally, in the radiopharmaceutical industry, enriched water () is bombarded with hydrogen ions in either a cyclotron or linear accelerator, creating fluorine-18. This is then synthesized into FDG and injected into a patient. It can also be used to make an extremely heavy version of water when combined with tritium (hydrogen-3): or . This compound has a density almost 30% greater than that of natural water. The accurate measurements of rely on proper procedures of analysis, sample preparation and storage. Paleoclimatology In ice cores, mainly Arctic and Antarctic, the ratio of to (known as δ) can be used to determine the temperature of precipitation through time. Assuming that atmospheric circulation and elevation has not changed significantly over the poles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon-13
Carbon-13 (13C) is a natural, stable isotope of carbon with a nucleus containing six protons and seven neutrons. As one of the environmental isotopes, it makes up about 1.1% of all natural carbon on Earth. Detection by mass spectrometry A mass spectrum of an organic compound will usually contain a small peak of one mass unit greater than the apparent molecular ion peak (M) of the whole molecule. This is known as the M+1 peak and comes from the few molecules that contain a 13C atom in place of a 12C. A molecule containing one carbon atom will be expected to have an M+1 peak of approximately 1.1% of the size of the M peak, as 1.1% of the molecules will have a 13C rather than a 12C. Similarly, a molecule containing two carbon atoms will be expected to have an M+1 peak of approximately 2.2% of the size of the M peak, as there is double the previous likelihood that any molecule will contain a 13C atom. In the above, the mathematics and chemistry have been simplified, however it can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isotopic Signatures
An isotopic signature (also isotopic fingerprint) is a ratio of non-radiogenic ' stable isotopes', stable radiogenic isotopes, or unstable radioactive isotopes of particular elements in an investigated material. The ratios of isotopes in a sample material are measured by isotope-ratio mass spectrometry against an isotopic reference material. This process is called isotope analysis. Stable isotopes The atomic mass of different isotopes affect their chemical kinetic behavior, leading to natural isotope separation processes. Carbon isotopes For example, different sources and sinks of methane have different affinity for the 12C and 13C isotopes, which allows distinguishing between different sources by the 13C/12C ratio in methane in the air. In geochemistry, paleoclimatology and paleoceanography this ratio is called Δ13C, δ13C. The ratio is calculated with respect to Δ13C#Reference standard, Pee Dee Belemnite (PDB) Reference Materials for Stable Isotope Analysis, standard: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
δ18O
In geochemistry, paleoclimatology and paleoceanography ''δ''18O or delta-O-18 is a measure of the ratio of stable isotopes oxygen-18 (18O) and oxygen-16 (16O). It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis. In paleosciences, 18O:16O data from corals, foraminifera and ice cores are used as a proxy for temperature. The definition is, in "per mil" (‰, parts per thousand): :\delta \ce = \left( \frac - 1 \right) \times 1000 ‰ where the standard has a known isotopic composition, such as Vienna Standard Mean Ocean Water (VSMOW). The fractionation can arise from kinetic, equilibrium, or mass-independent fractionation. Mechanism Foraminifera shells are composed of calcium carbonate (CaCO3) and are found in many common geological environments. The ratio of 18O to 16O in the shell is used to indirectly determine th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
