منابع مشابه
Interstellar isotope ratios from mm-wave molecular absorption spectra
We have measured galactic λ3mm absorption spectra of HCO+, HCN, HNC, and CS toward compact extragalactic continuum sources in order to derive the isotopic abundance ratios 12C/13C, 14N/15N, 16O/18O, and 32S/34S in local diffuse clouds. For carbon, our data confirm recent results for the local ISM: we find 12C/13C = 59 ± 2. For nitrogen, we find 14N/15N = 237(−21,+27) consistent with the Solar v...
متن کاملThe Abundance of Interstellar Nitrogen
Using the HST Goddard High Resolution Spectrograph (GHRS), we have obtained high S/N echelle observations of the weak interstellar N I 1160,1161 absorption doublet toward the stars Cas, Ori, Ori, Ori, Sco and Sco. In combination with a previous GHRS measurement of N I toward Oph, these new observations yield a mean interstellar gas-phase nitrogen abundance (per 10 H atoms) of 10 N/H = 75 4 ( 1 ...
متن کاملUse of stable isotope ratios for profiling of industrial ephedrine samples: application of hydrogen isotope ratios in combination with carbon and nitrogen.
The utility of hydrogen stable isotope ratio measurement by IR-MS for establishing the origin of ephedrine and pseudoephedrine (ephedrines), precursors of methamphetamine, was evaluated. There are two kinds of commercial semisynthetic ephedrines, one produced from molasses and the other from pyruvic acid. While the semisynthetic ephedrines derived from pyruvic acid cannot be discriminated from ...
متن کاملStable nitrogen isotope ratios of bone collagen reflect marine and terrestrial components of prehistoric human diet.
The delta 15N values of bone collagen from Eskimos and from Northwest Coast Indians dependent on salmon fishing are about 10 per mil more positive than those from agriculturalists in historic times. Among prehistoric humans, two groups dependent on marine food sources show bone collagen delta 15N values that are 4 to 6 per mil more positive than those from two agricultural groups. The nitrogen ...
متن کاملVariation in trophic shift for stable isotope ratios of carbon, nitrogen, and sulfur
Use of stable isotope ratios to trace pathways of organic matter among consumers requires knowledge of the isotopic shift between diet and consumer. Variation in trophic shift among consumers can be substantial. For data from the published literature and supplementary original data (excluding fluid-feeding consumers), the mean isotopic shift for C was +0.5 0.13‰ rather than 0.0‰, as commonly as...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1985
ISSN: 0074-1809
DOI: 10.1017/s0074180900243209