nitrogen isotopes การใช้

• Lighter isotopes of nitrogen are preferred in the reaction, leaving the heavier nitrogen isotopes in the residual matter.
• This method allows for the stable carbon and nitrogen isotopes to be chemically extracted from animal and human skeletal remains.
• A computer analysis of the nitrogen isotopes'behavior suggested that the initial jump had taken place in less than a decade.
• No other nitrogen isotopes are possible as they would fall outside the nuclear drip lines, leaking out a proton or neutron.
• Carbon and nitrogen isotope composition are used to reconstruct diet, and oxygen isotopes are used to determine geographic origin and paleoenvironment.
• Nitrogen isotopes indicate the trophic level position of various marine organisms ( reflective of the time the tissue samples were taken ).
• See Nitrogen 15 for one example of another nitrogen isotope . talk ) 23 : 11, 22 April 2008 ( UTC)
• In the famous Meselson Stahl experiment of 1958 he and Frank Stahl demonstrated through nitrogen isotope labeling that DNA is replicated semi-conservatively.
• Carbon and nitrogen isotope analysis of Buhla's bone collagen suggests that Buhla ate largely bison and elk, with occasional salmon and other fish.
• Okay, so I'm trying to calculate the relative abundance of the two nitrogen isotopes, knowing the mass of both isotopes and of nitrogen as a whole.
• Earth-and spacecraft-based measurements have led to improved knowledge of the Solar System formation considered the terrestrial value for the ratio of nitrogen isotopes to be primordial.
• She has built up an international reputation in meteoritics, publishing many papers on the carbon and nitrogen isotope geochemistry of primitive meteorites, on Martian meteorites, and on interstellar components of meteorites.
• Bioarchaeologists can examine teeth and look for the presence or absence of dental caries ( cavities ), use tooth wear analysis, or they can use stable isotope analysis, specifically through carbon and nitrogen isotopes.
• It has been shown that foliar stable nitrogen isotope ( 15 N ) abundance in " N . ampullaria " plants growing under forest canopy ( litterfall present ) is significantly lower than in plants without access to litterfall.
• By noting the types of algae in the sedimentary layers, along with concentrations of a nitrogen isotope that is another marker of fish abundance, the researchers were able to reconstruct a history of sockeye salmon since 200 B . C.
• This conclusion was reached upon showing that this reaction yields a nitrogen isotope effect, k 14 / k 15, of 1.0133?.0002 along with a hydrogen kinetic isotope effect of 3.2 at the leaving hydrogen.
• Rogers, K . M . ( 2003 ) . " Stable carbon and nitrogen isotope signatures indicate recovery of marine biota from sewage pollution at Moa Point, New Zealand . " Marine Pollution Bulletin 46 ( 7 ) : 821-827.
• For instance, determining nitrogen isotope effect along with hydrogen isotope effect was used to show that the reaction of 2-phenylethyltrimethylammonium ion with ethoxide in ethanol at 40 o C follows an E2 mechanism, as opposed to alternative non-concerted mechanisms.
• Using another telescope, astronomers from the University of Hawaii and the Joint Astronomy Center in Hilo measured the ratio of two nitrogen isotopes _ nitrogen-14 and nitrogen-15 in the comet, and this measurement also is believed to be a first.
• The isotopic signatures of stable carbon, hydrogen, and nitrogen isotopes at the layer of the bogs corresponding to 1908 were found to be inconsistent with the isotopic ratios measured in the adjacent layers, and this abnormality was not found in bogs located outside the area.