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Showing 1 to 20 of 31 for “"d13C"”.
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Validity, Reliability, and Sensitivity of the d13C Added Sugar Biomarker in Children and Adolescents
Currently, 17.1% of 2-19 year olds are obese. While obesity is a multifactorial disease, energy imbalance is commonly cited as a primary etiology. Excess consumption of added sugar (AS) from corn and cane sweeteners has been implicated as a leading contributor to weight gain in youth and adults. …
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The Use of Biomarker and Stable Isotope Analyses in Palaeopedology / Reconstruction of Middle and Late Quaternary Environmental and Climate History, with examples from Mt. Kilimanjaro, NE Siberia and NE Argentina
… stable carbon and nitrogen isotopes (d13C and d15N) in bulk soil organic matter (SOM) and on compound-specific isotope analysis (CSIA) of n-alkanes. The respective methods were partly optimized and then applied in multi-proxy analytical approaches to three selected palaeosol records, …
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Study of atmospheric carbon monoxide and methane
… trace gases. We measured the stable isotopes d13C and dD of atmospheric CH4 as well as d13C, d18O and the 14CO concentrations of atmospheric CO at Izana, Tenerife, from 1996 to 1999. We report the first directly measured dD seasonality for atmospheric background CH4. The large seasonal cycles …
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Sm-Nd and C-isotope chemostratigraphy of Ordovician epeiric sea carbonates, midcontinent of North America
… ancient marine environments. As a result, eNd, d13C and Sm/Nd profiles are developed as tools for interpreting epeiric sea carbonates. Previously, eNd and d13C profiles in epeiric sea carbonates have been used to study changes in the Nd isotope balance and C-cycle of adjacent ocean water. …
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Fluidassoziierte Brekzien als Monitor dolomitisierender und dedolomitisierender Lösungsströme in der Kantabrischen Zone (Nordspanien)
… (-12,73 bis 1,51 d18O ? PDB). Die d13C-Werte (PDB) zeigen keine große Varianz (2,56 bis 5,43 d13C ? PDB). Die Dolomite der Brekzienlokalitäten weisen geringere d18O- (PDB) und d13C-Werte auf. Die geringsten d18O- und d13C-Werte befinden sich in den Calciten. Die in dieser Arbeit …
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Establishing High-Resolution Hydrogeological, Geochemical and Isotopic Baseline Conditions of the Fresh Water Zone at a Field Research Site Near Brooks, Alberta, Canada
… methane and ethane concentrations, and biogenic d13C-CH4 values of <-82‰. Below the coals, ports were characterized by lower flow rates, higher d18O and d2H values of water and variable water types. Methane and ethane concentrations were lower compared to samples obtained from coals and d13C-CH4 …
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Multi-isotope analysis and the reconstruction of prey species palaeomigrations and palaeoecology
… strontium (87Sr/86Sr), oxygen (d18O), carbon(d13C), nitrogen (d15N) and sulphur (d34S). Teeth (enamel and dentine) were sequentially-sampled in order to reconstruct time-series isotopic profiles at an intra- and inter-individual scale, allowing an assessment of the applicability of these …
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Aspects of material transport and polycrystal growth in fractures
… Chapter 5 presents microstructural, stable (d13C, d18O) and radiogenic (87Sr/86Sr) isotope of antitaxial fibrous calcite veins from the Swiss Alps and New York State, USA. At least some veins are isolated in three dimensions, vein formation is initated by transgranular fracturing. Isotope …
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Chemostratigraphy of the Early Paleoproterozoic carbonate successions (Kaapvaal and Wyoming cratons)
… in South Africa. Limestones retain negative d13C values for over 60 m in the Vagner Formation, and for over 100 m in the lower part of the Duitschland Formation. Isotope compositions of TOC from the lower part of the Duitschland Formation reveal pronounced enrichment resulting in …
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Characterization of Mercury Transport and Fate in the Truckee River, NV, USA
… with the reach above, fish d15N and d13C varied. Below SBC all sites were impacted most notably in nitrogen, phosphorous, sulfate, and Hg concentrations that increased in all abiotic and biotic components. The latter reach varied Hg concentrations by components. Derby Dam is an …
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Composição da matéria orgânica no gradiente estuarino da Baía de Sepetiba/RJ
… de marcadores elementares (C/N), isotópicos (d13C e d15N) e moleculares (lignina, esteróis e hidrocarbonetos) em amostras de sedimento e de material particulado em suspensão, sendo que neste último compartimento só foi possível a análise da composição elementar e isotópica da matéria orgânica. …
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Palaeoenvironmental analysis of the upper Cenomanian and lower Turonian limestone beds in the Sergipe Basin, northeastern Brazil, based on microfacies analysis, micropalaeontology and stable isotopes
… südlichen Japaratuba-Gebiet konnte mit Hilfe der d13C-Kurve nachgewiesen werden. Die auftretenden Fluktuationen der Kohlenstoff-Kurve lassen eine Korrelation der einzelnen Profile zu, die mit der Biostratigraphie übereinstimmt.
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The Potential of Bulk and Amino-Acid Specific Isotope Ratio Mass Spectrometry of Human Hair in Forensic and Clinical Applications
… was used to analyze bulk isotope ratio of d13C, d15N and d34S values of human hair. Finally, we have applied LC-IRMS to measure amino acid in 20 different females from Jordan between the ages of 17 and 50 years. The preliminary studies suggest that for a relatively small sample size of 20 …
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Radiocarbon (Δ14C) and Stable Carbon (δ13C) Isotopic Composition of Dissolved Inorganic Carbon (DIC) in Baffin Bay
… residence times. However, very few DIC Δ14C and d13C data have been reported in the Arctic Ocean, comprising only a handful of stations in the Eurasian Basin, Canadian Basin, and Beaufort Sea. With this goal in mind, we conducted a study in which DIC samples were collected aboard the CCGS …
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Untersuchung der Variabilität des atmosphärischen Methanhaushalts hochpolarer Breiten anhand eines regionalen Trajektorienmodells und der Messung stabiler Isotope
… etwa 2.4 ‰ (Neumayer) bzw. 6.8 ‰ (Alert). Für d13C-CH4 ergibt sich ein Jahresgang von etwa 0.12 ‰ (Neumayer) bzw. 0.38 ‰ (Alert). Aus der Differenz der beiden Stationen leitet sich eine Trennung der mittleren troposphärischen CH4-Senke von e13C = (-7.2 ± 1.3) ‰ bzw. e2H = (-234 ± 13) ‰ her, die …
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Organic geochemical biosignatures in alkaline Hydrothermal ecosystems
… systems produced organic carbon with d13C outside of the usual biological range.
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In situ Metabolism and Biogeography of Phototrophic Consortia
… by determination of stable isotope ratios (d13C) of their specific biomarkers. Analysis of photosynthetic pigments by HPLC revealed the presence of high concentrations of BChl e and smaller amounts of BChl a, d and Chl a in the chemocline. Unexpectedly, isorenieratene and b-isorenieratene, …
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Paleoclimate reconstructions over the last century from a tropical speleothem on Niue Island, South Pacific
… variability in the stalagmite d18O and d13C time series agrees well with instrumental-derived ENSO phases (El Niño and La Niña events during 1866-2002) and the sea level pressure differential (Samoa-Fiji)-based SPCZ index (SPI) that controls the interdecadal hydroclimate variability. …
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The marine life of Atlantic salmon: evidence from the chemistry of scales
… although more strongly in the Frome. Yearly d13C values were correlated with median yearly sea surface temperature values for each degree of latitude and longitude across the North Atlantic, and maps produced of the correlation strengths. These maps suggest likely feeding grounds for each …
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STABLE ISOTOPE RATIOS AS A PROXY FOR HUMAN GEOGRAPHIC PROVENANCE: BIOGEOGRAPHICAL EVIDENCE FROM THE 2H, 18O, AND 13C SIGNATURES IN MODERN HUMAN TEETH
… notation as delta values in per mil (‰). Mean d13CVPDB values for all samples ranged from -9.47 ‰ to -11.31 ‰ (pooled mean = -10.37 ‰), which suggested a persistent C4 plant dietary influence at the time the sampled tooth enamel was forming and is consistent with the typical North American …
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