Sentences with phrase «isotopic ratio for»
This enabled a direct measurement of the 12C / 13C isotopic ratio for the Orion hot core of 14 + / - 1 and an estimated maximum value of 21.
https://arxiv.org/ Not exact matches
Next, the methane in this air is combusted to produce carbon dioxide, which is analysed for its carbon isotopic composition — or carbon - 13 to carbon - 12 ratio.
«THE stable carbon isotopic (13C / 12C) record of twentieth - century tree rings has been examined1 - 3 for evidence of the effects of the input of isotopically lighter fossil fuel CO2 (δ 13C ~ -25 ‰ relative to the primary PDB standard4), since the onset of major fossil fuel combustion during the mid-nineteenth century, on the 13C / 12C ratio of atmospheric CO2 (δ 13C ~ -7 ‰), which is assimilated by trees by photosynthesis.
In collaboration with the Institute for Arctic and Alpine Research (INSTAAR) of the University of Colorado, ESRL / GMD now routinely monitors carbon isotopic ratios of CO2 and CH4.
Which is ludicrous in the context of CO2, since we can measure isotopic ratio changes (indicating the change in old carbon versus fresh carbon) and have good accounting for human inputs to the system versus sources and sinks.
Because the different isotope ratios for the two kinds of plants propagate through the food chain, it is possible determine if the principal diet of a human or other animal consists primarily of C3 plants or C4 plants by measuring the isotopic signature of their collagen and other tissues.