نتایج جستجو برای: stable isotope

تعداد نتایج: 281992  

Journal: :Molecular & Cellular Proteomics 2006

2014
Kevin A. Johnston Paul D. Welch

Understanding the composition of paleodiets is crucially important for the archaeological investigation of lifeways and subsistence practices within ancient societies. Among the numerous research methods capable of investigating various elements of paleodiets, the use of stable isotope analysis has become increasingly popular. Advantages of this research technique include its ability to recogni...

2008

Picarro WS-CRDS-based analyzers are the first instruments to combine simple, turnkey operation with sensitivity and precision better than or equal to the IRMS (isotope ratio mass spectrometer) systems traditionally used in stable isotope labs. This opens the door for widespread exploitation of stable isotope studies in fields such as carbon/water cycle research, GHG (greenhouse gas) monitoring,...

2004
Margaret J. Schoeninger

Stable isotope ratios of carbon and nitrogen in bone have become increasingly frequent inclusions in archaeological reports over the past few decades. The majority of such studies has been done in North America, where the use of marine foods and the introduction of maize have been monitored. Similar questions have been addressed in Mesoamerica and South America. In Europe, stable isotope ratios...

2004
Seth D. Newsome Donald L. Phillips Brendan J. Culleton Tom P. Guilderson Paul L. Koch

The inherent sampling and preservational biases of the archaeological record make it difficult to quantify prehistoric human diets, especially in coastal settings, where populations had access to a wide range of marine and terrestrial food sources. In certain cases, geochemical proxies such as stable isotope ratios may be utilized to provide robust estimates on the relative proportions of vario...

2007
Koichi NAKAMURA Akiko WATANABE Noriko OKUDAIRA Osamu OKAZAKI Kenichi SUDO

An advantage of using LC-MS(WMS) for in vitro CYP inhibition screening is that it does not require extensive sample preparation and chromatographic separation. Attention must be paid, however, to ion suppression eŠects on analytes caused by the test compound as well as endogenous compounds. In this study, we have shown the ion suppression of 1?-hydroxymidazolam (analyte) and dextrorphan (IS) by...

2018
Susan R. Kennedy Todd E. Dawson Rosemary G. Gillespie

The Hawaiian Islands offer a unique opportunity to test how changes in the properties of an isolated ecosystem are propagated through the organisms that occur within that ecosystem. The age-structured arrangement of volcanic-derived substrates follows a regular progression over space and, by inference, time. We test how well documented successional changes in soil chemistry and associated veget...

2015
Nicole D. Kowalczyk André Chiaradia Tiana J. Preston Richard D. Reina

Unlike migratory seabirds with wide foraging ranges, resident seabirds forage in a relatively small range year-round and are thus particularly vulnerable to local shifts in prey availability. In order to manage their populations effectively, it is necessary to identify their key prey across and within years. Here, stomach content and stable isotope analyses were used to reconstruct the diet and...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1974
L M Libby L J Pandolfi

The stable isotope ratios of carbon, oxygen, and hydrogen have been measured for a German oak in wood samples of roughly three years each, for the years 1712-1954 A.D., and correlated with the existing weather records from England, Basel, and Geneva to evaluate the empirical temperature coefficients. Isotope ratios in a second official oak, measured for the years 1530-1800 A.D., show the cold t...

Journal: :Isotopes in environmental and health studies 2005
Peter Werle Christoph Dyroff Andreas Zahn Piero Mazzinghi Francesco D'amato

Diode-laser absorption spectroscopy finds increasing applications in the emerging field of stable isotope research. To meet the requirements of the water isotopes measurement challenge in environmental research, ways have to be found to cope with the present limitations of spectroscopic systems. In this article, we discuss an approach based on the Stark effect in molecular spectra to reduce the...

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