نتایج جستجو برای: n 14
تعداد نتایج: 1272662 فیلتر نتایج به سال:
LANGUAGE NOTE | Document text in Chinese; abstract also English.
 Developments research have made culturing human embryos beyond the 14-day limit seem technologically feasible. In article “Emerging Human Embryo Research Technologies, Rule, and Special Status of Embryo,” authors examine a proposal for new embryo embryoid guidelines by reviewing history emerging areas that are impacted these...
دراین تحقیق درمولکول c60، 6 اتم کربن به وسیله اتم های بور و 6 اتم دیگر کربن، به وسیله اتم های نیتروژن جایگزین شده اند. ساختارهای مولکول هتروفولرن اولیه c48(bn)6 و مولکول هتروفولرن پس ازجذب آمونیاک به منظور بررسی تاثیر جذبnh3 برروی اتم های بور مورد مطالعه قرار گرفت؛ به طوریکه درهر مرحله یک nh3 به مولکول اضافه شد تا اینکه برروی هر6 موقعیت بور، توسط مولکول های آمونیاک ، جذب صورت گرفت. در ابتدا ساخ...
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...
Many secreted signaling molecules are synthesized as precursors that undergo multiple maturation steps to generate their mature forms. The Saccharomyces cerevisiae mating pheromone a-factor is a C-terminally isoprenylated and carboxylmethylated dodecapeptide that is initially synthesized as a larger precursor containing 36 or 38 amino acids. We have previously shown that the maturation of a-fac...
A. Hutcheson,1,5,* C. Angell,3,5 J. A. Becker,7 A. S. Crowell,1,5 D. Dashdorj,2,7 B. Fallin,1,5 N. Fotiades,6 C. R. Howell,1,5 H. J. Karwowski,3,5 T. Kawano,6 J. H. Kelley,2,5 E. Kwan,1,5 R. A. Macri,7 R. O. Nelson,6 R. S. Pedroni,4,5 A. P. Tonchev,1,5 and W. Tornow1,5 1Department of Physics, Duke University, Durham, North Carolina 27708, USA 2North Carolina State University, Raleigh, North Car...
In this note we present a construction which improves the best known bound on minimal dispersion of large volume boxes in unit cube. Let d>1. The T⊂[0,1]d is defined as supremum taken over all axis parallel cube do not intersect T. n points infimum T such that |T|=n. Define “large volume” regime class volumes 14<r≤12. inverse denoted N(r,d). When large, upper N(r,d) order (r−14)−1. presented yi...
In 1988, Carbon-14 findings from three Accelerator Mass Spectrometer (AMS) Labs independently dated a sample removed from the Shroud of Turin: unarguably the most widely studied linen cloth in history. The dates reported ranged between 126
Using the California Institute of Technology/Jet Propulsion Laboratory two-dimensional transport model, with transport coefficients taken from Yang and Tung (1989), we study the time evolution of excess carbon 14 in the stratosphere and the troposphere from October, 1963 to December, 1966. The model provides a satisfactory simulation of the observed data. Due to the impulsive nature of its so...
Radiocarbon (carbon-14) data from the Aegean Bronze Age 1700-1400 B.C. show that the Santorini (Thera) eruption must have occurred in the late 17th century B.C. By using carbon-14 dates from the surrounding region, cultural phases, and Bayesian statistical analysis, we established a chronology for the initial Aegean Late Bronze Age cultural phases (Late Minoan IA, IB, and II). This chronology c...
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