نتایج جستجو برای: isotope ratio

تعداد نتایج: 530028  

2013
Honami Sato Tetsuji Onoue Tatsuo Nozaki Katsuhiko Suzuki

Anomalously high platinum group element concentrations have previously been reported for Upper Triassic deep-sea sediments, which are interpreted to be derived from an extraterrestrial impact event. Here we report the osmium (Os) isotope fingerprint of an extraterrestrial impact from Upper Triassic chert successions in Japan. Os isotope data exhibit a marked negative excursion from an initial O...

Journal: :journal of agricultural science and technology 2013
a. dadkhah

a factorial pot experiment based on randomized complete blocks design with fourreplications was carried out in order to evaluate salt tolerance of four sugar beet cultivarsincluding madison (british origin) and three iranian cultivars (7233-p12, 7233-p21 and7233-p29) using carbon isotope discrimination (δ). plants were grown in sand culturemedium in greenhouse conditions. sugar beet cultivars w...

Journal: :Environmental science & technology 2015
Hong-Bo Li Kai Chen Albert L Juhasz Lei Huang Lena Q Ma

Fingerprinting based on stable isotopes of lead (Pb) in blood and environmental media helps to identify Pb exposure pathways in children. However, previous studies used stable isotopes of total Pb in media. In this study, a wire rope production town in China (Zhuhang) was selected for investigating the effectiveness of using isotope ratios in bioaccessible Pb to identify childhood Pb exposure p...

Journal: :Rapid communications in mass spectrometry : RCM 2005
Gabriel J Bowen David A Winter Howard J Spero Robert A Zierenberg Mathew D Reeder Thure E Cerling James R Ehleringer

Bottled and packaged waters are an increasingly significant component of the human diet. These products are regulated at the regional, national, and international levels, and determining the authenticity of marketing and labeling claims represents a challenge to regulatory agencies. Here, we present a dataset of stable isotope ratios for bottled waters sampled worldwide, and consider potential ...

2008
Adam M. Taylor Renée Brooks Barbara Lachenbruch Jeffrey J. Morrell Steve Voelker

Cellulose is usually isolated from the other components of plant material for analysis of carbon stable isotope ratios (dC). However, many studies have shown a strong correlation between whole-wood and cellulose dC values, prompting debate about the necessity of cellulose extraction for tree-ring studies. The dC values were measured in whole wood, extractive-free wood, purified cellulose, aceto...

2012
Simona A. Ceriani James D. Roth Daniel R. Evans John F. Weishampel Llewellyn M. Ehrhart

In recent years, the use of intrinsic markers such as stable isotopes to link breeding and foraging grounds of migratory species has increased. Nevertheless, several assumptions still must be tested to interpret isotopic patterns found in the marine realm. We used a combination of satellite telemetry and stable isotope analysis to (i) identify key foraging grounds used by female loggerheads nes...

Journal: :American journal of physical anthropology 2010
Marie Louise S Jørkov Lars Jørgensen Niels Lynnerup

A systematic dietary investigation during Danish Roman Iron Age (1-375AD) is conducted by analyzing stable isotope ratios of carbon (δ(13) C) and nitrogen (δ(15) N) in the collagen of human and animal bone. The human sample comprises 77 individuals from 10 burial sites. In addition 31 samples of mammals and fish were analyzed from same geographical area. The investigation characterizes the huma...

2010
Takefumi Nakazawa Yoichiro Sakai Chih-hao Hsieh Tadatoshi Koitabashi Ichiro Tayasu Norio Yamamura Noboru Okuda

Characterizing relationships between individual body size and trophic niche position is essential for understanding how population and food-web dynamics are mediated by size-dependent trophic interactions. However, whether (and how) intraspecific size-trophic relationships (i.e., trophic ontogeny pattern at the population level) vary with time remains poorly understood. Using archival specimens...

2015
Gérald S. Remaud Maxime Julien Julien Parinet Pierrick Nun Richard J. Robins Patrick Höhener

The common practice of measuring the change in isotope ratio for the whole molecule using isotope ratio measurement by mass spectrometry leads to the loss of significant information of potential interest, since it is the position-specific fractionation which most closely reflects the effect of physicochemical processes. We have shown for MTBE, a common ground water contaminant, that isotopic qu...

Journal: :Journal of mass spectrometry : JMS 2008
Adam T Cawley Ulrich Flenker

The administration of synthetic steroid copies is one of the most important issues facing sports. Doping control laboratories accredited by the World Anti-Doping Agency (WADA) require methods of analysis that allow endogenous steroids to be distinguished from their synthetic analogs in urine. The ability to measure isotope distribution at natural abundance with high accuracy and precision has i...

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