نتایج جستجو برای: Carbon-14
تعداد نتایج: 631804 فیلتر نتایج به سال:
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The identification of human artifacts at the early archaeological site of Monte Verde in southern Chile has raised questions of when and how people reached the tip of South America without leaving much other evidence in the New World. Remains of nine species of marine algae were recovered from hearths and other features at Monte Verde II, an upper occupational layer, and were directly dated bet...
Precise and direct dating of the Minoan eruption of Santorini (Thera) in Greece, a global Bronze Age time marker, has been made possible by the unique find of an olive tree, buried alive in life position by the tephra (pumice and ashes) on Santorini. We applied so-called radiocarbon wiggle-matching to a carbon-14 sequence of tree-ring segments to constrain the eruption date to the range 1627-16...
1. Certain of the alpha-mercapto soaps and alpha-disulfo soaps are powerful germicides. 2. In the alpha-mercapto series, those soaps with 12 and 14 carbon atoms are most germicidal. In the disulfo series, the dicaprate, dilaurate, and dimyristate are most germicidal. The optimum number of carbon atoms varies with the test organism used. 3. These soaps, like others previously studied, show a mar...
Basal till was identified in two sediment cores collected about 69 kilometers southeast of Nantucket Island on the east and west sides of Great South Channel. These are the first samples of till collected on the outer continental shelf off the northeastern United States. The carbon-14 age of the total organic carbon in the tills provides a "no older than" age of about 20,000 years before presen...
Current models of the peopling of the higher-elevation zones of the Tibetan Plateau postulate that permanent occupation could only have been facilitated by an agricultural lifeway at ~3.6 thousand calibrated carbon-14 years before present. Here we report a reanalysis of the chronology of the Chusang site, located on the central Tibetan Plateau at an elevation of ~4270 meters above sea level. Th...
That is, carbon-14 decays into nitrogen-14, an electron, and an electron antineutrino. Laboratory experiments demonstrate that it is not possible to predict when any given nucleus will decay. In addition, the probability of decay in the next time interval dt is completely independent of how long the nucleus has lasted up to that point, be it an attosecond or a billion years. What this means is ...
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