carbon 13

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car·bon 13 (13C),

A stable natural isotope, 1.1% of natural carbon.
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References in periodicals archive ?
Stable carbon 13 and oxygen 18 isotopic analysis of the Nammal Formation has been carried out for the very first time from Nilawahan and Badshahpur sections in the Salt Range (Fig.
They found that the carbon 13 percentage in the background organic matter in the surrounding rock was different from that of the microstructures.
Artificial norandrosterone contains lower levels of carbon 13 than carbon 12, because it is produced from a plant source with less carbon 13 than normal dietary sources.
This form, called carbon 12, accounts for 99 percent of all carbon (carbon 13 and 14 account for the rest).
The runner-up wins a Borak carbon 13 ft match rod, one of the sport's top sellers.
The carbon 13 isotope is a by-product of photosynthesis, which generates oxygen.
According to Dr Etheridge,, the study attempted to answer some important questions from the analysis of carbon 13 isotopes, including why the atmospheric composition of methane has changed, how much of that change was due to human factors, and why pre-industrial levels were apparently so stable.
These results indicate that although the oxidation state of carbon 13 does not affect reduction of the quinone moiety, the quinone remains a poorer substrate for CR.
Here, he compares the ratio of carbon 13 to carbon 12 isotopes.
Mass spectrometric studies of carbon 13 varieties in corn and other grasses.
The unique Carbon 13 was a tag and could be identified because it did not occur naturally within the system.
Fung I, Field CB, Berry JA, Thompson MV, Randerson JT, Malmstrom CM, Vitousek PM, Collatz GJ, Sellers PJ, Randall DA, Denning AS, Badeck F, John J (1997) Carbon 13 exchanges between the atmosphere and biosphere.