Structure defects in malachite revealed by positron annihilation

Energy Technology Data Exchange (ETDEWEB)

Geffroy, B; Diallo, I; Paulin, R [Institut National des Sciences et Techniques Nucleaires, CEN/Saclay, 91 - Gif-sur-Yvette (France)

1984-01-01

Positron lifetime is measured between 77 and 400 K in two malachite samples with different mineralogical structures. The complex spectrum found in zoned malachite reveals a microporosity which remains stable in this range of temperature. Besides, above 200 K, equilibrium defects appear. Their formation energy is estimated to be Esub(f) = 0.27 +- 0.02 eV.

Testing of an automated online EA-IRMS method for fast and simultaneous carbon content and stable isotope measurement of aerosol samples

Science.gov (United States)

Major, István; Gyökös, Brigitta; Túri, Marianna; Futó, István; Filep, Ágnes; Hoffer, András; Molnár, Mihály

2016-04-01

Comprehensive atmospheric studies have demonstrated that carbonaceous aerosol is one of the main components of atmospheric particulate matter over Europe. Various methods, considering optical or thermal properties, have been developed for quantification of the accurate amount of both organic and elemental carbon constituents of atmospheric aerosol. The aim of our work was to develop an alternative fast and easy method for determination of the total carbon content of individual aerosol samples collected on prebaked quartz filters whereby the mass and surface concentration becomes simply computable. We applied the conventional "elemental analyzer (EA) coupled online with an isotope ratio mass spectrometer (IRMS)" technique which is ubiquitously used in mass spectrometry. Using this technique we are able to measure simultaneously the carbon stable isotope ratio of the samples, as well. During the developing process, we compared the EA-IRMS technique with an off-line catalytic combustion method worked out previously at Hertelendi Laboratory of Environmental Studies (HEKAL). We tested the combined online total carbon content and stable isotope ratio measurement both on standard materials and real aerosol samples. Regarding the test results the novel method assures, on the one hand, at least 95% of carbon recovery yield in a broad total carbon mass range (between 100 and 3000 ug) and, on the other hand, a good reproducibility of stable isotope measurements with an uncertainty of ± 0.2 per mill. Comparing the total carbon results obtained by the EA-IRMS and the off-line catalytic combustion method we found a very good correlation (R2=0.94) that proves the applicability of both preparation method. Advantages of the novel method are the fast and simplified sample preparation steps and the fully automated, simultaneous carbon stable isotope ratio measurement processes. Furthermore stable isotope ratio results can effectively be applied in the source apportionment

A new CF-IRMS system for quantifying stable isotopes of carbon monoxide from ice cores and small air samples

Directory of Open Access Journals (Sweden)

Z. Wang

2010-10-01

Full Text Available We present a new analysis technique for stable isotope ratios (δ¹³C and δ¹⁸O of atmospheric carbon monoxide (CO from ice core samples. The technique is an online cryogenic vacuum extraction followed by continuous-flow isotope ratio mass spectrometry (CF-IRMS; it can also be used with small air samples. The CO extraction system includes two multi-loop cryogenic cleanup traps, a chemical oxidant for oxidation to CO₂, a cryogenic collection trap, a cryofocusing unit, gas chromatography purification, and subsequent injection into a Finnigan Delta Plus IRMS. Analytical precision of 0.2‰ (±1δ for δ¹³C and 0.6‰ (±1δ for δ¹⁸O can be obtained for 100 mL (STP air samples with CO mixing ratios ranging from 60 ppbv to 140 ppbv (~268–625 pmol CO. Six South Pole ice core samples from depths ranging from 133 m to 177 m were processed for CO isotope analysis after wet extraction. To our knowledge, this is the first measurement of stable isotopes of CO in ice core air.

Soil water stable isotopes reveal evaporation dynamics at the soil–plant–atmosphere interface of the critical zone

Directory of Open Access Journals (Sweden)

M. Sprenger

2017-07-01

Full Text Available Understanding the influence of vegetation on water storage and flux in the upper soil is crucial in assessing the consequences of climate and land use change. We sampled the upper 20 cm of podzolic soils at 5 cm intervals in four sites differing in their vegetation (Scots Pine (Pinus sylvestris and heather (Calluna sp. and Erica Sp and aspect. The sites were located within the Bruntland Burn long-term experimental catchment in the Scottish Highlands, a low energy, wet environment. Sampling took place on 11 occasions between September 2015 and September 2016 to capture seasonal variability in isotope dynamics. The pore waters of soil samples were analyzed for their isotopic composition (δ2H and δ18O with the direct-equilibration method. Our results show that the soil waters in the top soil are, despite the low potential evaporation rates in such northern latitudes, kinetically fractionated compared to the precipitation input throughout the year. This fractionation signal decreases within the upper 15 cm resulting in the top 5 cm being isotopically differentiated to the soil at 15–20 cm soil depth. There are significant differences in the fractionation signal between soils beneath heather and soils beneath Scots pine, with the latter being more pronounced. But again, this difference diminishes within the upper 15 cm of soil. The enrichment in heavy isotopes in the topsoil follows a seasonal hysteresis pattern, indicating a lag time between the fractionation signal in the soil and the increase/decrease of soil evaporation in spring/autumn. Based on the kinetic enrichment of the soil water isotopes, we estimated the soil evaporation losses to be about 5 and 10 % of the infiltrating water for soils beneath heather and Scots pine, respectively. The high sampling frequency in time (monthly and depth (5 cm intervals revealed high temporal and spatial variability of the isotopic composition of soil waters, which can be critical

Energy landscape of all-atom protein-protein interactions revealed by multiscale enhanced sampling.

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Kei Moritsugu

2014-10-01

Full Text Available Protein-protein interactions are regulated by a subtle balance of complicated atomic interactions and solvation at the interface. To understand such an elusive phenomenon, it is necessary to thoroughly survey the large configurational space from the stable complex structure to the dissociated states using the all-atom model in explicit solvent and to delineate the energy landscape of protein-protein interactions. In this study, we carried out a multiscale enhanced sampling (MSES simulation of the formation of a barnase-barstar complex, which is a protein complex characterized by an extraordinary tight and fast binding, to determine the energy landscape of atomistic protein-protein interactions. The MSES adopts a multicopy and multiscale scheme to enable for the enhanced sampling of the all-atom model of large proteins including explicit solvent. During the 100-ns MSES simulation of the barnase-barstar system, we observed the association-dissociation processes of the atomistic protein complex in solution several times, which contained not only the native complex structure but also fully non-native configurations. The sampled distributions suggest that a large variety of non-native states went downhill to the stable complex structure, like a fast folding on a funnel-like potential. This funnel landscape is attributed to dominant configurations in the early stage of the association process characterized by near-native orientations, which will accelerate the native inter-molecular interactions. These configurations are guided mostly by the shape complementarity between barnase and barstar, and lead to the fast formation of the final complex structure along the downhill energy landscape.

Stable isotope research pool inventory

International Nuclear Information System (INIS)

1980-12-01

This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for non-destructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Materials Research Collection and does not designate whether a sample is out on loan or in reprocessing

Determination of Resistant Starch Assimilating Bacteria in Fecal Samples of Mice by In vitro RNA-Based Stable Isotope Probing

Science.gov (United States)

Herrmann, Elena; Young, Wayne; Rosendale, Douglas; Conrad, Ralf; Riedel, Christian U.; Egert, Markus

2017-01-01

The impact of the intestinal microbiota on human health is becoming increasingly appreciated in recent years. In consequence, and fueled by major technological advances, the composition of the intestinal microbiota in health and disease has been intensively studied by high throughput sequencing approaches. Observations linking dysbiosis of the intestinal microbiota with a number of serious medical conditions including chronic inflammatory disorders and allergic diseases suggest that restoration of the composition and activity of the intestinal microbiota may be a treatment option at least for some of these diseases. One possibility to shape the intestinal microbiota is the administration of prebiotic carbohydrates such as resistant starch (RS). In the present study, we aim at establishing RNA-based stable isotope probing (RNA-SIP) to identify bacterial populations that are involved in the assimilation of RS using anaerobic in vitro fermentation of murine fecal material with stable [U13C] isotope-labeled potato starch. Total RNA from these incubations was extracted, processed by gradient ultracentrifugation and fractionated by density. 16S rRNA gene sequences were amplified from reverse transcribed RNA of high and low density fractions suspected to contain labeled and unlabeled RNA, respectively. Phylogenetic analysis of the obtained sequences revealed a distinct subset of the intestinal microbiota involved in starch metabolism. The results suggest Bacteroidetes, in particular genera affiliated with Prevotellaceae, as well as members of the Ruminococcacea family to be primary assimilators of resistant starch due to a significantly higher relative abundance in higher density fractions in RNA samples isolated after 2 h of incubation. Using high performance liquid chromatography coupled to isotope ratio mass spectrometry (HPLC-IRMS) analysis, some stable isotope label was recovered from acetate, propionate and butyrate. Here, we demonstrate the suitability of RNA

Determination of Resistant Starch Assimilating Bacteria in Fecal Samples of Mice by In vitro RNA-Based Stable Isotope Probing

Directory of Open Access Journals (Sweden)

Elena Herrmann

2017-07-01

Full Text Available The impact of the intestinal microbiota on human health is becoming increasingly appreciated in recent years. In consequence, and fueled by major technological advances, the composition of the intestinal microbiota in health and disease has been intensively studied by high throughput sequencing approaches. Observations linking dysbiosis of the intestinal microbiota with a number of serious medical conditions including chronic inflammatory disorders and allergic diseases suggest that restoration of the composition and activity of the intestinal microbiota may be a treatment option at least for some of these diseases. One possibility to shape the intestinal microbiota is the administration of prebiotic carbohydrates such as resistant starch (RS. In the present study, we aim at establishing RNA-based stable isotope probing (RNA-SIP to identify bacterial populations that are involved in the assimilation of RS using anaerobic in vitro fermentation of murine fecal material with stable [U13C] isotope-labeled potato starch. Total RNA from these incubations was extracted, processed by gradient ultracentrifugation and fractionated by density. 16S rRNA gene sequences were amplified from reverse transcribed RNA of high and low density fractions suspected to contain labeled and unlabeled RNA, respectively. Phylogenetic analysis of the obtained sequences revealed a distinct subset of the intestinal microbiota involved in starch metabolism. The results suggest Bacteroidetes, in particular genera affiliated with Prevotellaceae, as well as members of the Ruminococcacea family to be primary assimilators of resistant starch due to a significantly higher relative abundance in higher density fractions in RNA samples isolated after 2 h of incubation. Using high performance liquid chromatography coupled to isotope ratio mass spectrometry (HPLC-IRMS analysis, some stable isotope label was recovered from acetate, propionate and butyrate. Here, we demonstrate the

Identity of active methanotrophs in landfill cover soil as revealed by DNA-stable isotope probing.

Science.gov (United States)

Cébron, Aurélie; Bodrossy, Levente; Chen, Yin; Singer, Andrew C; Thompson, Ian P; Prosser, James I; Murrell, J Colin

2007-10-01

A considerable amount of methane produced during decomposition of landfill waste can be oxidized in landfill cover soil by methane-oxidizing bacteria (methanotrophs) thus reducing greenhouse gas emissions to the atmosphere. The identity of active methanotrophs in Roscommon landfill cover soil, a slightly acidic peat soil, was assessed by DNA-stable isotope probing (SIP). Landfill cover soil slurries were incubated with (13)C-labelled methane and under either nutrient-rich nitrate mineral salt medium or water. The identity of active methanotrophs was revealed by analysis of (13)C-labelled DNA fractions. The diversity of functional genes (pmoA and mmoX) and 16S rRNA genes was analyzed using clone libraries, microarrays and denaturing gradient gel electrophoresis. 16S rRNA gene analysis revealed that the cover soil was mainly dominated by Type II methanotrophs closely related to the genera Methylocella and Methylocapsa and to Methylocystis species. These results were supported by analysis of mmoX genes in (13)C-DNA. Analysis of pmoA gene diversity indicated that a significant proportion of active bacteria were also closely related to the Type I methanotrophs, Methylobacter and Methylomonas species. Environmental conditions in the slightly acidic peat soil from Roscommon landfill cover allow establishment of both Type I and Type II methanotrophs.

New insights on ecosystem mercury cycling revealed by stable isotopes of mercury in water flowing from a headwater peatland catchment

Science.gov (United States)

Glenn E. Woerndle; Martin Tsz-Ki Tsui; Stephen D. Sebestyen; Joel D. Blum; Xiangping Nie; Randall K. Kolka

2018-01-01

Stable isotope compositions of mercury (Hg) were measured in the outlet stream and in soil cores at different landscape positions in a 9.7-ha boreal upland-peatland catchment. An acidic permanganate/persulfate digestion procedure was validated for water samples with high dissolved organic matter (DOM) concentrations through Hg spike addition analysis. We report a...

Optimizing sample pretreatment for compound-specific stable carbon isotopic analysis of amino sugars in marine sediment

Science.gov (United States)

Zhu, R.; Lin, Y.-S.; Lipp, J. S.; Meador, T. B.; Hinrichs, K.-U.

2014-09-01

Amino sugars are quantitatively significant constituents of soil and marine sediment, but their sources and turnover in environmental samples remain poorly understood. The stable carbon isotopic composition of amino sugars can provide information on the lifestyles of their source organisms and can be monitored during incubations with labeled substrates to estimate the turnover rates of microbial populations. However, until now, such investigation has been carried out only with soil samples, partly because of the much lower abundance of amino sugars in marine environments. We therefore optimized a procedure for compound-specific isotopic analysis of amino sugars in marine sediment, employing gas chromatography-isotope ratio mass spectrometry. The whole procedure consisted of hydrolysis, neutralization, enrichment, and derivatization of amino sugars. Except for the derivatization step, the protocol introduced negligible isotopic fractionation, and the minimum requirement of amino sugar for isotopic analysis was 20 ng, i.e., equivalent to ~8 ng of amino sugar carbon. Compound-specific stable carbon isotopic analysis of amino sugars obtained from marine sediment extracts indicated that glucosamine and galactosamine were mainly derived from organic detritus, whereas muramic acid showed isotopic imprints from indigenous bacterial activities. The δ13C analysis of amino sugars provides a valuable addition to the biomarker-based characterization of microbial metabolism in the deep marine biosphere, which so far has been lipid oriented and biased towards the detection of archaeal signals.

Protein Stable Isotope Fingerprinting (P-SIF): Multidimensional Protein Chromatography Coupled to Stable Isotope-Ratio Mass Spectrometry

Science.gov (United States)

Pearson, A.; Bovee, R. J.; Mohr, W.; Tang, T.

2012-12-01

As metagenomics increases our insight into microbial community diversity and metabolic potential, new approaches are required to determine the biogeochemical expression of this potential within ecosystems. Because stable isotopic analysis of the major bioactive elements (C, N) has been used historically to map flows of substrates and energy among macroscopic food webs, similar principles may apply to microbes. To address this challenge, we have developed a new analytical approach called Protein Stable Isotope Fingerprinting (P-SIF). P-SIF generates natural stable isotopic fingerprints of microbial individual or community proteomes. The main advantage of P-SIF is the potential to bridge the gap between diversity and function, thereby providing a window into the "black box" of environmental microbiology and helping to decipher the roles of uncultivated species. Our method implements a three-way, orthogonal scheme to separate mixtures of whole proteins into subfractions dominated by single or closely-related proteins. Protein extracts first are isoelectrically focused in a gel-free technique that yields 12 fractions separated over a gradient of pH 3-10. Each fraction then is separated by size-exclusion chromatography into 20 pools, ranging from >100kD to ~10kD. Finally, each of these pools is subjected to HPLC and collected in 40 time-slices based on protein hydrophobicity. Theoretical calculation reveals that the true chromatographic resolution of the total scheme is 5000, somewhat less than the 9600 resulting fractions. High-yielding fractions are subjected to δ13C analysis by spooling-wire microcombustion irMS (SWiM-irMS) optimized for samples containing 1-5 nmol carbon. Here we will present the method, results for a variety of pure cultures, and preliminary data for a sample of mixed environmental proteins. The data show the promise of this method for unraveling the metabolic complexity hidden within microbial communities.

Stable isotope research pool inventory

International Nuclear Information System (INIS)

1984-03-01

This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

Chemical fractionation of radionuclides and stable elements in aquatic plants of the Yenisei River.

Science.gov (United States)

Bolsunovsky, Alexander

2011-09-01

The Yenisei River is contaminated with artificial radionuclides released by one of the Russian nuclear plants. The aquatic plants growing in the radioactively contaminated parts of the river contain artificial radionuclides. The aim of the study was to investigate accumulation of artificial radionuclides and stable elements by submerged plants of the Yenisei River and estimate the strength of their binding to plant biomass by using a new sequential extraction scheme. The aquatic plants sampled were: Potamogeton lucens, Fontinalis antipyretica, and Batrachium kauffmanii. Gamma-spectrometric analysis of the samples of aquatic plants has revealed more than 20 radionuclides. We also investigated the chemical fractionation of radionuclides and stable elements in the biomass and rated radionuclides and stable elements based on their distribution in biomass. The greatest number of radionuclides strongly bound to biomass cell structures was found for Potamogeton lucens and the smallest for Batrachium kauffmanii. For Fontinalis antipyretica, the number of distribution patterns that were similar for both radioactive isotopes and their stable counterparts was greater than for the other studied species. The transuranic elements (239)Np and (241)Am were found in the intracellular fraction of the biomass, and this suggested their active accumulation by the plants.

Existing and emerging technologies for measuring stable isotope labelled retinol in biological samples: isotope dilution analysis of body retinol stores.

Science.gov (United States)

Preston, Tom

2014-01-01

This paper discusses some of the recent improvements in instrumentation used for stable isotope tracer measurements in the context of measuring retinol stores, in vivo. Tracer costs, together with concerns that larger tracer doses may perturb the parameter under study, demand that ever more sensitive mass spectrometric techniques are developed. GCMS is the most widely used technique. It has high sensitivity in terms of sample amount and uses high resolution GC, yet its ability to detect low isotope ratios is limited by background noise. LCMSMS may become more accessible for tracer studies. Its ability to measure low level stable isotope tracers may prove superior to GCMS, but it is isotope ratio MS (IRMS) that has been designed specifically for low level stable isotope analysis through accurate analysis of tracer:tracee ratios (the tracee being the unlabelled species). Compound-specific isotope analysis, where GC is interfaced to IRMS, is gaining popularity. Here, individual 13C-labelled compounds are separated by GC, combusted to CO2 and transferred on-line for ratiometric analysis by IRMS at the ppm level. However, commercially-available 13C-labelled retinol tracers are 2 - 4 times more expensive than deuterated tracers. For 2H-labelled compounds, GC-pyrolysis-IRMS has now become more generally available as an operating mode on the same IRMS instrument. Here, individual compounds are separated by GC and pyrolysed to H2 at high temperature for analysis by IRMS. It is predicted that GC-pyrolysis-IRMS will facilitate low level tracer procedures to measure body retinol stores, as has been accomplished in the case of fatty acids and amino acids. Sample size requirements for GC-P-IRMS may exceed those of GCMS, but this paper discusses sample preparation procedures and predicts improvements, particularly in the efficiency of sample introduction.

Stable isotope research pool inventory

International Nuclear Information System (INIS)

1982-01-01

This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for nondestructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Material Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

Congener-specific accumulation and trophic transfer of polychlorinated biphenyls in spider crab food webs revealed by stable isotope analysis

Energy Technology Data Exchange (ETDEWEB)

Bodin, N. [IFREMER, DCN-BE, Technopole Brest-Iroise, Pointe du Diable, 29280 Plouzane (France); LPTC-UMR 5472 CNRS, Universite de Bordeaux 1, 351 cours de la Liberation, 33400 Talence (France)], E-mail: bodin.nathalie@caramail.com; Le Loc' h, F. [IRD, UR 070 RAP, Centre de Recherche Halieutique, Avenue Jean Monnet, B.P. 171, 34203 Sete Cedex (France); Caisey, X.; Le Guellec, A.-M.; Abarnou, A.; Loizeau, V. [IFREMER, DCN-BE, Technopole Brest-Iroise, Pointe du Diable, 29280 Plouzane (France); Latrouite, D. [IFREMER, DCB-STH, Technopole Brest-Iroise, Pointe du Diable, 29280 Plouzane (France)

2008-01-15

Polychlorobiphenyls (PCB) and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C) were analyzed in the spider crab (Maja brachydactyla) food web from the Iroise Sea (Western Brittany) and the Seine Bay (Eastern English Channel). PCB concentrations were all significantly higher in organisms from the Seine Bay than those from the Iroise Sea. PCB patterns were strongly related to the feeding mode of the species, and increased influence of higher chlorinated congeners was highlighted with trophic position of the organisms. PCB concentrations (lipid normalized) were significantly related to the isotopically derived trophic level (TL) in spider crab food webs. The highest trophic magnification factors (TMFs) were calculated for the congeners with 2,4,5-substitution, and were lower in the Seine Bay compared to the Iroise Sea. The confrontation of PCB and TL data also revealed biotransformation capacity of decapod crustaceans for specific congeners based on structure-activity relations. - The influence of feeding mode and trophic position on the fate of PCBs in spider crab food webs is discussed by using a stable isotopic approach.

Stable subcutaneous cartilage regeneration of bone marrow stromal cells directed by chondrocyte sheet.

Science.gov (United States)

Li, Dan; Zhu, Lian; Liu, Yu; Yin, Zongqi; Liu, Yi; Liu, Fangjun; He, Aijuan; Feng, Shaoqing; Zhang, Yixin; Zhang, Zhiyong; Zhang, Wenjie; Liu, Wei; Cao, Yilin; Zhou, Guangdong

2017-05-01

In vivo niche plays an important role in regulating differentiation fate of stem cells. Due to lack of proper chondrogenic niche, stable cartilage regeneration of bone marrow stromal cells (BMSCs) in subcutaneous environments is always a great challenge. This study explored the feasibility that chondrocyte sheet created chondrogenic niche retained chondrogenic phenotype of BMSC engineered cartilage (BEC) in subcutaneous environments. Porcine BMSCs were seeded into biodegradable scaffolds followed by 4weeks of chondrogenic induction in vitro to form BEC, which were wrapped with chondrocyte sheets (Sheet group), acellular small intestinal submucosa (SIS, SIS group), or nothing (Blank group) respectively and then implanted subcutaneously into nude mice to trace the maintenance of chondrogenic phenotype. The results showed that all the constructs in Sheet group displayed typical cartilaginous features with abundant lacunae and cartilage specific matrices deposition. These samples became more mature with prolonged in vivo implantation, and few signs of ossification were observed at all time points except for one sample that had not been wrapped completely. Cell labeling results in Sheet group further revealed that the implanted BEC directly participated in cartilage formation. Samples in both SIS and Blank groups mainly showed ossified tissue at all time points with partial fibrogenesis in a few samples. These results suggested that chondrocyte sheet could create a chondrogenic niche for retaining chondrogenic phenotype of BEC in subcutaneous environment and thus provide a novel research model for stable ectopic cartilage regeneration based on stem cells. In vivo niche plays an important role in directing differentiation fate of stem cells. Due to lack of proper chondrogenic niche, stable cartilage regeneration of bone marrow stromal cells (BMSCs) in subcutaneous environments is always a great challenge. The current study demonstrated that chondrocyte sheet generated by

Sampling on Quasicrystals

OpenAIRE

Grepstad, Sigrid

2011-01-01

We prove that quasicrystals are universal sets of stable sampling in any dimension. Necessary and sufficient density conditions for stable sampling and interpolation sets in one dimension are studied in detail.

Stable isotope composition of human fingernails from Slovakia

International Nuclear Information System (INIS)

Grolmusová, Zuzana; Rapčanová, Anna; Michalko, Juraj; Čech, Peter; Veis, Pavel

2014-01-01

Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ 13 C and δ 15 N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in 13 C and 15 N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ 13 C and δ 15 N values. These data were compared to previously published δ 13 C and δ 15 N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ 13 C and δ 15 N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied

Stable isotope research pool inventory

International Nuclear Information System (INIS)

1986-08-01

This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high-abundance, naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56. All requests for the loan of samples should be submitted with a summary of the purpose of the loan to: Iotope Distribution Office, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37831. Requests from non-DOE contractors and from foreign institutions require DOE approval

Enthalpy and high temperature relaxation kinetics of stable vapor-deposited glasses of toluene

International Nuclear Information System (INIS)

Bhattacharya, Deepanjan; Sadtchenko, Vlad

2014-01-01

Stable non-crystalline toluene films of micrometer and nanometer thicknesses were grown by vapor deposition at distinct rates and probed by fast scanning calorimetry. Fast scanning calorimetry is shown to be extremely sensitive to the structure of the vapor-deposited phase and was used to characterize simultaneously its kinetic stability and its thermodynamic properties. According to our analysis, transformation of vapor-deposited samples of toluene during heating with rates in excess 10 5 K s −1 follows the zero-order kinetics. The transformation rate correlates strongly with the initial enthalpy of the sample, which increases with the deposition rate according to sub-linear law. Analysis of the transformation kinetics of vapor-deposited toluene films of various thicknesses reveal a sudden increase in the transformation rate for films thinner than 250 nm. The change in kinetics seems to correlate with the surface roughness scale of the substrate. The implications of these findings for the formation mechanism and structure of vapor-deposited stable glasses are discussed

Intraclade heterogeneity in nitrogen utilization by marine prokaryotes revealed using stable isotope probing coupled with tag sequencing (Tag-SIP

Directory of Open Access Journals (Sweden)

Michael Morando

2016-12-01

Full Text Available Nitrogen can greatly influence the structure and productivity of microbial communities through its relative availability and form. However, roles of specific organisms in the uptake of different nitrogen species remain poorly characterized. Most studies seeking to identify agents of assimilation have been correlative, indirectly linking activity measurements (e.g., nitrate uptake with the presence or absence of biological markers, particularly functional genes and their transcripts. Evidence is accumulating of previously underappreciated functional diversity in major microbial subpopulations, which may confer physiological advantages under certain environmental conditions leading to ecotype divergence. This microdiversity further complicates our view of genetic variation in environmental samples requiring the development of more targeted approaches. Here, next-generation tag sequencing was successfully coupled with stable isotope probing (Tag-SIP to assess the ability of individual phylotypes to assimilate a particular N source. Our results provide the first direct evidence of nitrate utilization by organisms thought to lack the genes required for this process including the heterotrophic clades SAR11 and the Archaeal Marine Group II (MG-II. We also provide new direct evidence of in situ nitrate utilization by the cyanobacterium Prochlorococcus in support of recent findings. Furthermore, these results revealed widespread functional heterogeneity, i.e. different levels of N assimilation within clades, likely reflecting niche partitioning by ecotypes. The addition of nitrate utilization to ecosystem and ecosystem models by these globally dominant clades will likely improve the mechanistic accuracy of these models.

A novel high-temperature combustion based system for stable isotope analysis of dissolved organic carbon in aqueous samples. : I development and validation

NARCIS (Netherlands)

Federherr, E.; Cerli, C.; Kirkels, F. M. S. A.; Kalbitz, K.; Kupka, H. J.; Dunsbach, R.; Lange, L.; Schmidt, T. C.

2014-01-01

RATIONALE: Traditionally, dissolved organic carbon (DOC) stable isotope analysis (SIA) is performed using either offline sample preparation followed by elemental analyzer/isotope ratiomass spectrometry (EA/IRMS) or a wet chemical oxidation (WCO)-based device coupled to an isotope ratio mass

Stable isotope composition of human fingernails from Slovakia

Energy Technology Data Exchange (ETDEWEB)

Grolmusová, Zuzana, E-mail: zuzana.grolmusova@geology.sk [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Rapčanová, Anna [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); Michalko, Juraj; Čech, Peter [State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Veis, Pavel [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia)

2014-10-15

Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ{sup 13}C and δ{sup 15}N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in {sup 13}C and {sup 15}N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ{sup 13}C and δ{sup 15}N values. These data were compared to previously published δ{sup 13}C and δ{sup 15}N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ{sup 13}C and δ{sup 15}N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied.

Stable isotope mass spectrometry in petroleum exploration

International Nuclear Information System (INIS)

Mathur, Manju

1997-01-01

The stable isotope mass spectrometry plays an important role to evaluate the stable isotopic composition of hydrocarbons. The isotopic ratios of certain elements in petroleum samples reflect certain characteristics which are useful for petroleum exploration

Pup Vibrissae Stable Isotopes Reveal Geographic Differences in Adult Female Southern Sea Lion Habitat Use during Gestation.

Directory of Open Access Journals (Sweden)

Alastair M M Baylis

Full Text Available Individuals within populations often differ substantially in habitat use, the ecological consequences of which can be far reaching. Stable isotope analysis provides a convenient and often cost effective means of indirectly assessing the habitat use of individuals that can yield valuable insights into the spatiotemporal distribution of foraging specialisations within a population. Here we use the stable isotope ratios of southern sea lion (Otaria flavescens pup vibrissae at the Falkland Islands, in the South Atlantic, as a proxy for adult female habitat use during gestation. A previous study found that adult females from one breeding colony (Big Shag Island foraged in two discrete habitats, inshore (coastal or offshore (outer Patagonian Shelf. However, as this species breeds at over 70 sites around the Falkland Islands, it is unclear if this pattern is representative of the Falkland Islands as a whole. In order to characterize habitat use, we therefore assayed carbon (δ13C and nitrogen (δ15N ratios from 65 southern sea lion pup vibrissae, sampled across 19 breeding colonies at the Falkland Islands. Model-based clustering of pup isotope ratios identified three distinct clusters, representing adult females that foraged inshore, offshore, and a cluster best described as intermediate. A significant difference was found in the use of inshore and offshore habitats between West and East Falkland and between the two colonies with the largest sample sizes, both of which are located in East Falkland. However, habitat use was unrelated to the proximity of breeding colonies to the Patagonian Shelf, a region associated with enhanced biological productivity. Our study thus points towards other factors, such as local oceanography and its influence on resource distribution, playing a prominent role in inshore and offshore habitat use.

Combined bio-logging and stable isotopes reveal individual specialisations in a benthic coastal seabird, the Kerguelen shag.

Directory of Open Access Journals (Sweden)

Elodie C M Camprasse

Full Text Available Individual specialisations, which involve the repetition of specific behaviours or dietary choices over time, have been suggested to benefit animals by avoiding competition with conspecifics and increasing individual foraging efficiency. Among seabirds, resident and benthic species are thought to be good models to study inter-individual variation as they repetitively exploit the same environment. We investigated foraging behaviour, isotopic niche and diet in the Kerguelen shag Phalacrocorax verrucosus during both the incubation and chick-rearing periods for the same individuals to determine the effect of sex, breeding stage, body mass and morphometrics on mean foraging metrics and their consistency. There were large differences between individuals in foraging behaviour and consistency, with strong individual specialisations in dive depths and heading from the colony. Stable isotopes revealed specialisations in feeding strategies, across multiple temporal scales. Specifically, individuals showed medium term specialisations in feeding strategies during the breeding season, as well as long-term consistency. A clustering analysis revealed 4 different foraging strategies displaying significantly different δ15N values and body masses. There were no sex or stage biases to clusters and individuals in different clusters did not differ in their morphology. Importantly, the results suggest that the different strategies emphasized were related to individual prey preferences rather than intrinsic characteristics.

Determination of stable cesium and strontium in rice samples by inductively coupled plasma mass spectrometry

Science.gov (United States)

Srinuttrakul, W.; Yoshida, S.

2017-06-01

For long-term radiation dose assessment models, food ingestion is one of the major exposure pathways to human. In general, the stable isotopes can serve as analogues of radioisotopes. In this study, rice samples were collected from 30 paddy fields in Si Sa Ket, Yasothon and Roi Et in the northeast of Thailand in November 2014. The concentrations of stable cesium (Cs-133) and strontium (Sr-88) in polished rice were determined by inductively coupled plasma mass spectrometry (ICP-MS). The standard reference material of rice flour (NIST 1568a) with spiked Cs and Sr was used to validate the analytical method. The concentration of Cs in polished rice from Si Sa Ket, Yasothon and Roi Et was 0.158 ± 0.167 mg kg-1, 0.090 ± 0.117 mg kg-1 and 0.054 ± 0.031 mg kg-1, respectively. The concentration of Sr in polished rice from Si Sa Ket, Yasothon and Roi Et was 0.351 ± 0.108 mg kg-1, 0.364 ± 0.215 mg kg-1 and 0.287 ± 0.102 mg kg-1, respectively. Comparison of the results with Japanese data before the Fukushima Di-ichi nuclear power plant accident showed that the concentrations of both Cs and Sr for Thai rice were higher than those for Japanese rice.

Determination of stable cesium and strontium in rice samples by inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Srinuttrakul, W; Yoshida, S

2017-01-01

For long-term radiation dose assessment models, food ingestion is one of the major exposure pathways to human. In general, the stable isotopes can serve as analogues of radioisotopes. In this study, rice samples were collected from 30 paddy fields in Si Sa Ket, Yasothon and Roi Et in the northeast of Thailand in November 2014. The concentrations of stable cesium (Cs-133) and strontium (Sr-88) in polished rice were determined by inductively coupled plasma mass spectrometry (ICP-MS). The standard reference material of rice flour (NIST 1568a) with spiked Cs and Sr was used to validate the analytical method. The concentration of Cs in polished rice from Si Sa Ket, Yasothon and Roi Et was 0.158 ± 0.167 mg kg -1 , 0.090 ± 0.117 mg kg -1 and 0.054 ± 0.031 mg kg -1 , respectively. The concentration of Sr in polished rice from Si Sa Ket, Yasothon and Roi Et was 0.351 ± 0.108 mg kg -1 , 0.364 ± 0.215 mg kg -1 and 0.287 ± 0.102 mg kg -1 , respectively. Comparison of the results with Japanese data before the Fukushima Di-ichi nuclear power plant accident showed that the concentrations of both Cs and Sr for Thai rice were higher than those for Japanese rice. (paper)

Stable isotope labeling strategy based on coding theory

Energy Technology Data Exchange (ETDEWEB)

Kasai, Takuma; Koshiba, Seizo; Yokoyama, Jun; Kigawa, Takanori, E-mail: kigawa@riken.jp [RIKEN Quantitative Biology Center (QBiC), Laboratory for Biomolecular Structure and Dynamics (Japan)

2015-10-15

We describe a strategy for stable isotope-aided protein nuclear magnetic resonance (NMR) analysis, called stable isotope encoding. The basic idea of this strategy is that amino-acid selective labeling can be considered as “encoding and decoding” processes, in which the information of amino acid type is encoded by the stable isotope labeling ratio of the corresponding residue and it is decoded by analyzing NMR spectra. According to the idea, the strategy can diminish the required number of labelled samples by increasing information content per sample, enabling discrimination of 19 kinds of non-proline amino acids with only three labeled samples. The idea also enables this strategy to combine with information technologies, such as error detection by check digit, to improve the robustness of analyses with low quality data. Stable isotope encoding will facilitate NMR analyses of proteins under non-ideal conditions, such as those in large complex systems, with low-solubility, and in living cells.

Stable isotope labeling strategy based on coding theory

International Nuclear Information System (INIS)

Kasai, Takuma; Koshiba, Seizo; Yokoyama, Jun; Kigawa, Takanori

2015-01-01

We describe a strategy for stable isotope-aided protein nuclear magnetic resonance (NMR) analysis, called stable isotope encoding. The basic idea of this strategy is that amino-acid selective labeling can be considered as “encoding and decoding” processes, in which the information of amino acid type is encoded by the stable isotope labeling ratio of the corresponding residue and it is decoded by analyzing NMR spectra. According to the idea, the strategy can diminish the required number of labelled samples by increasing information content per sample, enabling discrimination of 19 kinds of non-proline amino acids with only three labeled samples. The idea also enables this strategy to combine with information technologies, such as error detection by check digit, to improve the robustness of analyses with low quality data. Stable isotope encoding will facilitate NMR analyses of proteins under non-ideal conditions, such as those in large complex systems, with low-solubility, and in living cells

Stable isotopes in mid-ocean ridge hydrothermal systems: Interactions between fluids, minerals, and organisms

Science.gov (United States)

Shanks, W. C., III; Böhlke, J. K.; Seal, R. R., II

Studies of abundance variations of light stable isotopes in nature have had a tremendous impact on all aspects of geochemistry since the development, in 1947, of a gas source isotope ratio mass spectrometer capable of measuring small variations in stable isotope ratios [Nier, 1947] Stable isotope geochemistry is now a mature field, as witnessed by the proliferation of commercially available mass spectrometers installed at virtually every major academic, government, and private-sector research geochemistry laboratory. A recent search of a literature database revealed over 3,000 articles that utilized stable isotope geochemistry over the last 20 years. Nonetheless, many exciting new technical developments are leading to exciting new discoveries and applications. In particular, micro analytical techniques involving new generations of laser- and ion-microprobes are revolutionizing the types of analyses that can be done on spot sizes as small as a few tens of micrometers [Shanks and Criss, 1989]. New generations of conventional gas source and thermal ionization mass spectrometers, with high levels of automation and increased sensitivity and precision, are allowing analyses of large numbers of samples, like those needed for stable isotope stratigraphy in marine sediments, and are enabling the development and application of new isotopic systems.

Contamination risk of stable isotope samples during milling.

Science.gov (United States)

Isaac-Renton, M; Schneider, L; Treydte, K

2016-07-15

Isotope analysis of wood is an important tool in dendrochronology and ecophysiology. Prior to mass spectrometry analysis, wood must be homogenized, and a convenient method involves a ball mill capable of milling samples directly in sample tubes. However, sample-tube plastic can contaminate wood during milling, which could lead to biological misinterpretations. We tested possible contamination of whole wood and cellulose samples during ball-mill homogenization for carbon and oxygen isotope measurements. We used a multi-factorial design with two/three steel milling balls, two sample amounts (10 mg, 40 mg), and two milling times (5 min, 10 min). We further analyzed abrasion by milling empty tubes, and measured the isotope ratios of pure contaminants. A strong risk exists for carbon isotope bias through plastic contamination: the δ(13) C value of polypropylene deviated from the control by -6.77‰. Small fibers from PTFE filter bags used during cellulose extraction also present a risk as the δ(13) C value of this plastic deviated by -5.02‰. Low sample amounts (10 mg) showed highest contamination due to increased abrasion during milling (-1.34‰), which is further concentrated by cellulose extraction (-3.38‰). Oxygen isotope measurements were unaffected. A ball mill can be used to homogenize samples within test tubes prior to oxygen isotope analysis, but not prior to carbon or radiocarbon isotope analysis. There is still a need for a fast, simple and contamination-free sample preparation procedure. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Water stable isotope measurements of Antarctic samples by means of IRMS and WS-CRDS techniques

Science.gov (United States)

Michelini, Marzia; Bonazza, Mattia; Braida, Martina; Flora, Onelio; Dreossi, Giuliano; Stenni, Barbara

2010-05-01

In the last years in the scientific community there has been an increasing interest for the application of stable isotope techniques to several environmental problems such as drinking water safeguarding, groundwater management, climate change, soils and paleoclimate studies etc. For example, the water stable isotopes, being natural tracers of the hydrological cycle, have been extensively used as tools to characterize regional aquifers and to reconstruct past temperature changes from polar ice cores. Here the need for improvements in analytical techniques: the high request for information calls for technologies that can offer a great quantity of analyses in short times and with low costs. Furthermore, sometimes it is difficult to obtain big amount of samples (as is the case for Antarctic ice cores or interstitial water) preventing the possibility to replicate the analyses. Here, we present oxygen and hydrogen measurements performed on water samples covering a big range of isotopic values (from very negative antarctic precipitation to mid-latitude precipitation values) carried out with both the conventional Isotope Ratio Mass Spectrometry (IRMS) technique and with a new method based on laser absorption techniques, the Wavelenght Scanned Cavity Ringdown Spectroscopy (WS-CRDS). This study is focusing on improving the precision of the measurements carried out with WS-CRDS in order to extensively apply this method to Antarctic ice core paleoclimate studies. The WS-CRDS is a variation of the CRDS developed in 1988 by O'Keef and Deacon. In CRDS a pulse of light goes through a box with high reflective inner surfaces; when there is no sample in the box the light beam doesn't find any obstacle in its path, but the reflectivity of the walls is not perfect so eventually there will be an absorption of the light beam; when the sample is injected in the box there is absorption and the difference between the time of absorption without and with sample is proportional to the quantity

Equilibrium contact angle or the most-stable contact angle?

Science.gov (United States)

Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

2014-04-01

It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation. © 2013 Elsevier B.V. All rights reserved.

Calcium stable isotope geochemistry

Energy Technology Data Exchange (ETDEWEB)

Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

2016-08-01

This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

Calcium stable isotope geochemistry

International Nuclear Information System (INIS)

Gausonne, Nikolaus; Schmitt, Anne-Desiree; Heuser, Alexander; Wombacher, Frank; Dietzel, Martin; Tipper, Edward; Schiller, Martin

2016-01-01

This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki.

Directory of Open Access Journals (Sweden)

Massimiliano Drago

Full Text Available Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ(13C and δ(15N of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months, resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years, may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago.

Interactive Stable Ray Tracing

DEFF Research Database (Denmark)

Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

2017-01-01

Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

Time difference of arrival estimation of microseismic signals based on alpha-stable distribution

Science.gov (United States)

Jia, Rui-Sheng; Gong, Yue; Peng, Yan-Jun; Sun, Hong-Mei; Zhang, Xing-Li; Lu, Xin-Ming

2018-05-01

Microseismic signals are generally considered to follow the Gauss distribution. A comparison of the dynamic characteristics of sample variance and the symmetry of microseismic signals with the signals which follow α-stable distribution reveals that the microseismic signals have obvious pulse characteristics and that the probability density curve of the microseismic signal is approximately symmetric. Thus, the hypothesis that microseismic signals follow the symmetric α-stable distribution is proposed. On the premise of this hypothesis, the characteristic exponent α of the microseismic signals is obtained by utilizing the fractional low-order statistics, and then a new method of time difference of arrival (TDOA) estimation of microseismic signals based on fractional low-order covariance (FLOC) is proposed. Upon applying this method to the TDOA estimation of Ricker wavelet simulation signals and real microseismic signals, experimental results show that the FLOC method, which is based on the assumption of the symmetric α-stable distribution, leads to enhanced spatial resolution of the TDOA estimation relative to the generalized cross correlation (GCC) method, which is based on the assumption of the Gaussian distribution.

Measurements of stable isotope ratios in milk samples from a farm placed in the mountains of Transylvania

Energy Technology Data Exchange (ETDEWEB)

Magdas, D. A., E-mail: gabriela.cristea@itim-cj.ro; Cristea, G., E-mail: gabriela.cristea@itim-cj.ro; Bot, A.; Puscas, R.; Radu, S.; Mirel, V. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania); Cordea, D. V.; Mihaiu, M. [University of Agricultural Science and Veterinary Medicine, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania)

2013-11-13

Product origin is of great importance for consumers especially because its association in consumer's perception with food quality, freedom from disease or pollution. Stable isotope ratio analysis is a powerful technique in food authenticity and traceability control which has been introduced within the European wine industry to ensure authenticity of wine provenance and to detect adulteration. Isotopic ratios measurements have also been successfully to other food commodities like: fruit juices, honey and dairy foods. The δ{sup 18}O and δ{sup 2}H content in milk water reflects the isotope composition of the ground water drunk by animals. Seasonal effects are also very important: in summer, milk water contains higher δ{sup 18}O and δ{sup 2}H values due to the fresh plants that are ate by animals. Relative carbon stable isotope abundances in total milk reflect the isotopic composition of the diet fed to the dairy cows. In this study the hydrogen, oxygen and carbon isotopic composition of 15 milk samples coming from a unit placed in the mountains of Transylvania was investigated. The distribution of the obtained isotopic values was than discussed taking into account that all the animals were feed with the same type of forage and consumed water was taken from the same source.

Measurements of stable isotope ratios in milk samples from a farm placed in the mountains of Transylvania

International Nuclear Information System (INIS)

Magdas, D. A.; Cristea, G.; Bot, A.; Puscas, R.; Radu, S.; Mirel, V.; Cordea, D. V.; Mihaiu, M.

2013-01-01

Product origin is of great importance for consumers especially because its association in consumer's perception with food quality, freedom from disease or pollution. Stable isotope ratio analysis is a powerful technique in food authenticity and traceability control which has been introduced within the European wine industry to ensure authenticity of wine provenance and to detect adulteration. Isotopic ratios measurements have also been successfully to other food commodities like: fruit juices, honey and dairy foods. The δ 18 O and δ 2 H content in milk water reflects the isotope composition of the ground water drunk by animals. Seasonal effects are also very important: in summer, milk water contains higher δ 18 O and δ 2 H values due to the fresh plants that are ate by animals. Relative carbon stable isotope abundances in total milk reflect the isotopic composition of the diet fed to the dairy cows. In this study the hydrogen, oxygen and carbon isotopic composition of 15 milk samples coming from a unit placed in the mountains of Transylvania was investigated. The distribution of the obtained isotopic values was than discussed taking into account that all the animals were feed with the same type of forage and consumed water was taken from the same source

Local Search Approaches in Stable Matching Problems

Directory of Open Access Journals (Sweden)

Toby Walsh

2013-10-01

Full Text Available The stable marriage (SM problem has a wide variety of practical applications, ranging from matching resident doctors to hospitals, to matching students to schools or, more generally, to any two-sided market. In the classical formulation, n men and n women express their preferences (via a strict total order over the members of the other sex. Solving an SM problem means finding a stable marriage where stability is an envy-free notion: no man and woman who are not married to each other would both prefer each other to their partners or to being single. We consider both the classical stable marriage problem and one of its useful variations (denoted SMTI (Stable Marriage with Ties and Incomplete lists where the men and women express their preferences in the form of an incomplete preference list with ties over a subset of the members of the other sex. Matchings are permitted only with people who appear in these preference lists, and we try to find a stable matching that marries as many people as possible. Whilst the SM problem is polynomial to solve, the SMTI problem is NP-hard. We propose to tackle both problems via a local search approach, which exploits properties of the problems to reduce the size of the neighborhood and to make local moves efficiently. We empirically evaluate our algorithm for SM problems by measuring its runtime behavior and its ability to sample the lattice of all possible stable marriages. We evaluate our algorithm for SMTI problems in terms of both its runtime behavior and its ability to find a maximum cardinality stable marriage. Experimental results suggest that for SM problems, the number of steps of our algorithm grows only as O(n log(n, and that it samples very well the set of all stable marriages. It is thus a fair and efficient approach to generate stable marriages. Furthermore, our approach for SMTI problems is able to solve large problems, quickly returning stable matchings of large and often optimal size, despite the

Revealing stable processing products from ribosome-associated small RNAs by deep-sequencing data analysis.

Science.gov (United States)

Zywicki, Marek; Bakowska-Zywicka, Kamilla; Polacek, Norbert

2012-05-01

The exploration of the non-protein-coding RNA (ncRNA) transcriptome is currently focused on profiling of microRNA expression and detection of novel ncRNA transcription units. However, recent studies suggest that RNA processing can be a multi-layer process leading to the generation of ncRNAs of diverse functions from a single primary transcript. Up to date no methodology has been presented to distinguish stable functional RNA species from rapidly degraded side products of nucleases. Thus the correct assessment of widespread RNA processing events is one of the major obstacles in transcriptome research. Here, we present a novel automated computational pipeline, named APART, providing a complete workflow for the reliable detection of RNA processing products from next-generation-sequencing data. The major features include efficient handling of non-unique reads, detection of novel stable ncRNA transcripts and processing products and annotation of known transcripts based on multiple sources of information. To disclose the potential of APART, we have analyzed a cDNA library derived from small ribosome-associated RNAs in Saccharomyces cerevisiae. By employing the APART pipeline, we were able to detect and confirm by independent experimental methods multiple novel stable RNA molecules differentially processed from well known ncRNAs, like rRNAs, tRNAs or snoRNAs, in a stress-dependent manner.

How to take environmental samples for stable isotope analyses

International Nuclear Information System (INIS)

Rogers, K.M.

2009-01-01

It is possible to analyse a diverse range of samples for environmental investigations. The main types are soil/sediments, vegetation, fauna, shellfish, waste and water. Each type of samples requires different storage and collection methods. Outlined here are the preferred methods of collection to ensure maximum sample integrity and reliability. (author).

How to take environmental samples for stable isotope analyses

International Nuclear Information System (INIS)

Rogers, K.M.

2013-01-01

It is possible to analyse a diverse range of samples for environmental investigations. The main types are soil/sediments, vegetation, fauna, shellfish, waste and water. Each type of samples requires different storage and collection methods. Outlined here are the preferred methods of collection to ensure maximum sample integrity and reliability. (author).

How to take environmental samples for stable isotope analyses

International Nuclear Information System (INIS)

Rogers, K.M.

2012-01-01

It is possible to analyse a diverse range of samples for environmental investigations. The main types are soil/sediments, vegetation, fauna, shellfish, waste and water. Each type of samples requires different storage and collection methods. Outlined here are the preferred methods of collection to ensure maximum sample integrity and reliability. (author).

How to take environmental samples for stable isotope analyses

International Nuclear Information System (INIS)

Rogers, K.M.

2009-01-01

It is possible to analyse a diverse range of samples for environmental investigations. The main types are soil/sediments, vegetation, fauna, shellfish, waste and water. Each type of samples requires different storage and collection methods. Outlined here are the preferred methods of collection to ensure maximum sample integrity and reliability. (author)

Deposition of radionuclides and stable elements in Tokai-mura

Energy Technology Data Exchange (ETDEWEB)

Ueno, Takashi; Amano, Hikaru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

This report presents the data of deposition of radionuclides (Sep. 1993-March 2001) and stable elements (Sep. 1993-Oct. 1995) in Tokai-mura. To evaluate the migration of radionuclides and stable elements from the atmosphere to the ground surface, atmospheric deposition samples were collected from Sep. 1993 to March 2001 with three basins (distance to grand surface were 1.5 m, 4 m, 10 m) set up in the enclosure of JAERI in Tokai-mura, Ibaraki-ken, Japan. Monthly samples were evaporated to dryness to obtain residual samples and measured with a well type Ge detector for {sup 7}Be, {sup 40}K, {sup 137}Cs and {sup 210}Pb. According to the analysis of radioactivity, clear seasonal variations with spring peaks of deposition weight (dry) and deposition amounts of all objective radionuclides were found. Correlation analysis of deposition data also showed that these radionuclides can be divided into two groups. A part of dried sample was irradiated to reactor neutrons at JRR-4 for determination of stable element's deposition. (author)

The Nature of Stable Insomnia Phenotypes

Science.gov (United States)

Pillai, Vivek; Roth, Thomas; Drake, Christopher L.

2015-01-01

Study Objectives: We examined the 1-y stability of four insomnia symptom profiles: sleep onset insomnia; sleep maintenance insomnia; combined onset and maintenance insomnia; and neither criterion (i.e., insomnia cases that do not meet quantitative thresholds for onset or maintenance problems). Insomnia cases that exhibited the same symptom profile over a 1-y period were considered to be phenotypes, and were compared in terms of clinical and demographic characteristics. Design: Longitudinal. Setting: Urban, community-based. Participants: Nine hundred fifty-four adults with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition based current insomnia (46.6 ± 12.6 y; 69.4% female). Interventions: None. Measurements and results: At baseline, participants were divided into four symptom profile groups based on quantitative criteria. Follow-up assessment 1 y later revealed that approximately 60% of participants retained the same symptom profile, and were hence judged to be phenotypes. Stability varied significantly by phenotype, such that sleep onset insomnia (SOI) was the least stable (42%), whereas combined insomnia (CI) was the most stable (69%). Baseline symptom groups (cross-sectionally defined) differed significantly across various clinical indices, including daytime impairment, depression, and anxiety. Importantly, however, a comparison of stable phenotypes (longitudinally defined) did not reveal any differences in impairment or comorbid psychopathology. Another interesting finding was that whereas all other insomnia phenotypes showed evidence of an elevated wake drive both at night and during the day, the “neither criterion” phenotype did not; this latter phenotype exhibited significantly higher daytime sleepiness despite subthreshold onset and maintenance difficulties. Conclusions: By adopting a stringent, stability-based definition, this study offers timely and important data on the longitudinal trajectory of specific insomnia phenotypes. With

Discrimination of ginseng cultivation regions using light stable isotope analysis.

Science.gov (United States)

Kim, Kiwook; Song, Joo-Hyun; Heo, Sang-Cheol; Lee, Jin-Hee; Jung, In-Woo; Min, Ji-Sook

2015-10-01

Korean ginseng is considered to be a precious health food in Asia. Today, thieves frequently compromise ginseng farms by pervasive theft. Thus, studies regarding the characteristics of ginseng according to growth region are required in order to deter ginseng thieves and prevent theft. In this study, 6 regions were selected on the basis of Korea regional criteria (si, gun, gu), and two ginseng-farms were randomly selected from each of the 6 regions. Then 4-6 samples of ginseng were acquired from each ginseng farm. The stable isotopic compositions of H, O, C, and N of the collected ginseng samples were analyzed. As a result, differences in the hydrogen isotope ratios could be used to distinguish regional differences, and differences in the nitrogen isotope ratios yielded characteristic information regarding the farms from which the samples were obtained. Thus, stable isotope values could be used to differentiate samples according to regional differences. Therefore, stable isotope analysis serves as a powerful tool to discriminate the regional origin of Korean ginseng samples from across Korea. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Forensic Stable Isotope Biogeochemistry

Science.gov (United States)

Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

2016-06-01

Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

Studies on determination of stable elements in sea water and organisms

International Nuclear Information System (INIS)

Anon.

1974-01-01

The existing conditions of stable elements including Co, Zn, Cs, Ce and Eu in sea water were determined by adding radioactive tracers, and determination methods were discussed. 60 Co added to sea water revealed to be kept in solution in 93 per cent of non-filtrated sea water, and in 98 per cent of filtrated sea water. 65 Zn also added to sea water showed to be kept in solution in 97 per cent of both non-filtrated and filtrated sea water. Both elements seemed to exist as particle or ion smaller than 0.45 μ, which solved in sea water. On the other hand, in both Ce and Eu of rare earth elements, about 80 per cent of them presented in the residue, but the treatment of sea water by hydrochroric acid solubilized 80 to 90 per cent of them in filtrated sea water. One of the instrumental analysis, irradiation analysis by nuclear reactor, was applied: each of preconcentration procedure by ion exchange method for Co and Zn in sea water and drying up sample marine organisms to ash content combined with irradiation analysis. Chemical recovery of both 60 Co and 65 Zn in sea water by preconcentration procedure reached more than 95 per cent. As to marine organisms, Co, Zn, and Cs could be determined with only 100 to 200 mg. of ash content obtained from sample marine organisms showing 80 per cent of chemical yield of the carrier through whole the procedure of analysis in almost all the samples. The chemical recovery of Ce and Eu in sea water and marine organisms by the preconcentration procedure reached about 85 per cent, and chemical yield through whole the procedure of analysis was more than 60 per cent. Concentration factor of Co and Zn in fishes and shells, especially that of muscles, obtained by stable elements determination method was almost 10 times that by RI tracer method. The difference of chemical forms between RI tracer and stable isotope affected not only to physiological metabolism but also to food chains. (Kanao, K.)

The nature of stable insomnia phenotypes.

Science.gov (United States)

Pillai, Vivek; Roth, Thomas; Drake, Christopher L

2015-01-01

We examined the 1-y stability of four insomnia symptom profiles: sleep onset insomnia; sleep maintenance insomnia; combined onset and maintenance insomnia; and neither criterion (i.e., insomnia cases that do not meet quantitative thresholds for onset or maintenance problems). Insomnia cases that exhibited the same symptom profile over a 1-y period were considered to be phenotypes, and were compared in terms of clinical and demographic characteristics. Longitudinal. Urban, community-based. Nine hundred fifty-four adults with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition based current insomnia (46.6 ± 12.6 y; 69.4% female). None. At baseline, participants were divided into four symptom profile groups based on quantitative criteria. Follow-up assessment 1 y later revealed that approximately 60% of participants retained the same symptom profile, and were hence judged to be phenotypes. Stability varied significantly by phenotype, such that sleep onset insomnia (SOI) was the least stable (42%), whereas combined insomnia (CI) was the most stable (69%). Baseline symptom groups (cross-sectionally defined) differed significantly across various clinical indices, including daytime impairment, depression, and anxiety. Importantly, however, a comparison of stable phenotypes (longitudinally defined) did not reveal any differences in impairment or comorbid psychopathology. Another interesting finding was that whereas all other insomnia phenotypes showed evidence of an elevated wake drive both at night and during the day, the 'neither criterion' phenotype did not; this latter phenotype exhibited significantly higher daytime sleepiness despite subthreshold onset and maintenance difficulties. By adopting a stringent, stability-based definition, this study offers timely and important data on the longitudinal trajectory of specific insomnia phenotypes. With the exception of daytime sleepiness, few clinical differences are apparent across stable phenotypes. �

Stable isotopes reveal sources of precipitation in the Qinghai Lake Basin of the northeastern Tibetan Plateau

International Nuclear Information System (INIS)

Cui, Bu-Li; Li, Xiao-Yan

2015-01-01

on the TP. - Highlights: • Stable isotopes reveal sources of precipitation in the Qinghai Lake Basin. • Southwest Asian Monsoon could not reach the northeastern Tibetan Plateau. • Vapor contribution from lake evaporation to precipitation cannot be ignored

Stable isotopes reveal sources of precipitation in the Qinghai Lake Basin of the northeastern Tibetan Plateau

Energy Technology Data Exchange (ETDEWEB)

Cui, Bu-Li, E-mail: cuibuli@ieecas.cn [State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi' an 710061 (China); College of Resources Science and Technology, Beijing Normal University, Beijing 100875 (China); Li, Xiao-Yan [State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875 (China); College of Resources Science and Technology, Beijing Normal University, Beijing 100875 (China)

2015-09-15

fundamental to water cycling on the TP. - Highlights: • Stable isotopes reveal sources of precipitation in the Qinghai Lake Basin. • Southwest Asian Monsoon could not reach the northeastern Tibetan Plateau. • Vapor contribution from lake evaporation to precipitation cannot be ignored.

Stable isotope analysis

International Nuclear Information System (INIS)

Tibari, Elghali; Taous, Fouad; Marah, Hamid

2014-01-01

This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

The structure of mAG, a monomeric mutant of the green fluorescent protein Azami-Green, reveals the structural basis of its stable green emission

International Nuclear Information System (INIS)

Ebisawa, Tatsuki; Yamamura, Akihiro; Kameda, Yasuhiro; Hayakawa, Kou; Nagata, Koji; Tanokura, Masaru

2010-01-01

The crystal structure of a monomeric mutant of Azami-Green (mAG) from G. fascicularis was determined at 2.2 Å resolution. Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first known monomeric green-emitting fluorescent protein that is not a variant of Aequorea victoria green fluorescent protein (avGFP). These two green fluorescent proteins are only 27% identical in their amino-acid sequences. mAG is more similar in its amino-acid sequence to four fluorescent proteins: Dendra2 (a green-to-red irreversibly photoconverting fluorescent protein), Dronpa (a bright-and-dark reversibly photoswitchable fluorescent protein), KikG (a tetrameric green-emitting fluorescent protein) and Kaede (another green-to-red irreversibly photoconverting fluorescent protein). To reveal the structural basis of stable green emission by mAG, the 2.2 Å crystal structure of mAG has been determined and compared with the crystal structures of avGFP, Dronpa, Dendra2, Kaede and KikG. The structural comparison revealed that the chromophore formed by Gln62-Tyr63-Gly64 (QYG) and the fixing of the conformation of the imidazole ring of His193 by hydrogen bonds and van der Waals contacts involving His193, Arg66 and Thr69 are likely to be required for the stable green emission of mAG. The crystal structure of mAG will contribute to the design and development of new monomeric fluorescent proteins with faster maturation, brighter fluorescence, improved photostability, new colours and other preferable properties as alternatives to avGFP and its variants

Stable isotopes in Lithuanian bioarcheological material

Science.gov (United States)

Skipityte, Raminta; Jankauskas, Rimantas; Remeikis, Vidmantas

2015-04-01

Investigation of bioarcheological material of ancient human populations allows us to understand the subsistence behavior associated with various adaptations to the environment. Feeding habits are essential to the survival and growth of ancient populations. Stable isotope analysis is accepted tool in paleodiet (Schutkowski et al, 1999) and paleoenvironmental (Zernitskaya et al, 2014) studies. However, stable isotopes can be useful not only in investigating human feeding habits but also in describing social and cultural structure of the past populations (Le Huray and Schutkowski, 2005). Only few stable isotope investigations have been performed before in Lithuanian region suggesting a quite uniform diet between males and females and protein intake from freshwater fish and animal protein. Previously, stable isotope analysis has only been used to study a Stone Age population however, more recently studies have been conducted on Iron Age and Late medieval samples (Jacobs et al, 2009). Anyway, there was a need for more precise examination. Stable isotope analysis were performed on human bone collagen and apatite samples in this study. Data represented various ages (from 5-7th cent. to 18th cent.). Stable carbon and nitrogen isotope analysis on medieval populations indicated that individuals in studied sites in Lithuania were almost exclusively consuming C3 plants, C3 fed terrestrial animals, and some freshwater resources. Current investigation demonstrated social differences between elites and country people and is promising in paleodietary and daily life reconstruction. Acknowledgement I thank prof. dr. G. Grupe, Director of the Anthropological and Palaeoanatomical State Collection in Munich for providing the opportunity to work in her laboratory. The part of this work was funded by DAAD. Antanaitis-Jacobs, Indre, et al. "Diet in early Lithuanian prehistory and the new stable isotope evidence." Archaeologia Baltica 12 (2009): 12-30. Le Huray, Jonathan D., and Holger

Persistent organic pollutants and stable isotopes in biopsy samples (2004/2006) from Southern Resident killer whales

International Nuclear Information System (INIS)

Krahn, Margaret M.; Hanson, M. Bradley; Baird, Robin W.; Boyer, Richard H.; Burrows, Douglas G.; Emmons, Candice K.; Ford, John K.B.; Jones, Linda L.; Noren, Dawn P.; Ross, Peter S.; Schorr, Gregory S.; Collier, Tracy K.

2007-01-01

'Southern Resident' killer whales include three 'pods' (J, K and L) that reside primarily in Puget Sound/Georgia Basin during the spring, summer and fall. This population was listed as 'endangered' in the US and Canada following a 20% decline between 1996 and 2001. The current study, using blubber/epidermis biopsy samples, contributes contemporary information about potential factors (i.e., levels of pollutants or changes in diet) that could adversely affect Southern Residents. Carbon and nitrogen stable isotopes indicated J- and L-pod consumed prey from similar trophic levels in 2004/2006 and also showed no evidence for a large shift in the trophic level of prey consumed by L-pod between 1996 and 2004/2006. ΣPCBs decreased for Southern Residents biopsied in 2004/2006 compared to 1993-1995. Surprisingly, however, a three-year-old male whale (J39) had the highest concentrations of ΣPBDEs, ΣHCHs and HCB. POP ratio differences between J- and L-pod suggested that they occupy different ranges in winter

Stable convergence and stable limit theorems

CERN Document Server

Häusler, Erich

2015-01-01

The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

Tracing metal-silicate segregation and late veneer in the Earth and the ureilite parent body with palladium stable isotopes

Science.gov (United States)

Creech, J. B.; Moynier, F.; Bizzarro, M.

2017-11-01

Stable isotope studies of highly siderophile elements (HSE) have the potential to yield valuable insights into a range of geological processes. In particular, the strong partitioning of these elements into metal over silicates may lead to stable isotope fractionation during metal-silicate segregation, making them sensitive tracers of planetary differentiation processes. We present the first techniques for the precise determination of palladium stable isotopes by MC-ICPMS using a 106Pd-110Pd double-spike to correct for instrumental mass fractionation. Results are expressed as the per mil (‰) difference in the 106Pd/105Pd ratio (δ106Pd) relative to an in-house solution standard (Pd_IPGP) in the absence of a certified Pd isotopic standard. Repeated analyses of the Pd isotopic composition of the chondrite Allende demonstrate the external reproducibility of the technique of ±0.032‰ on δ106Pd. Using these techniques, we have analysed Pd stable isotopes from a range of terrestrial and extraterrestrial samples. We find that chondrites define a mean δ106Pdchondrite = -0.19 ± 0.05‰. Ureilites reveal a weak trend towards heavier δ106Pd with decreasing Pd content, similar to recent findings based on Pt stable isotopes (Creech et al., 2017), although fractionation of Pd isotopes is significantly less than for Pt, possibly related to its weaker metal-silicate partitioning behaviour and the limited field shift effect. Terrestrial mantle samples have a mean δ106Pdmantle = -0.182 ± 0.130‰, which is consistent with a late-veneer of chondritic material after core formation.

Multiple surveys employing a new sample-processing protocol reveal the genetic diversity of placozoans in Japan.

Science.gov (United States)

Miyazawa, Hideyuki; Nakano, Hiroaki

2018-03-01

Placozoans, flat free-living marine invertebrates, possess an extremely simple bauplan lacking neurons and muscle cells and represent one of the earliest-branching metazoan phyla. They are widely distributed from temperate to tropical oceans. Based on mitochondrial 16S rRNA sequences, 19 haplotypes forming seven distinct clades have been reported in placozoans to date. In Japan, placozoans have been found at nine locations, but 16S genotyping has been performed at only two of these locations. Here, we propose a new processing protocol, "ethanol-treated substrate sampling," for collecting placozoans from natural environments. We also report the collection of placozoans from three new locations, the islands of Shikine-jima, Chichi-jima, and Haha-jima, and we present the distribution of the 16S haplotypes of placozoans in Japan. Multiple surveys conducted at multiple locations yielded five haplotypes that were not reported previously, revealing high genetic diversity in Japan, especially at Shimoda and Shikine-jima Island. The observed geographic distribution patterns were different among haplotypes; some were widely distributed, while others were sampled only from a single location. However, samplings conducted on different dates at the same sites yielded different haplotypes, suggesting that placozoans of a given haplotype do not inhabit the same site constantly throughout the year. Continued sampling efforts conducted during all seasons at multiple locations worldwide and the development of molecular markers within the haplotypes are needed to reveal the geographic distribution pattern and dispersal history of placozoans in greater detail.

Metabolic studies in man using stable isotopes

International Nuclear Information System (INIS)

Faust, H.; Jung, K.; Krumbiegel, P.

1993-01-01

In this project, stable isotope compounds and stable isotope pharmaceuticals were used (with emphasis on the application of 15 N) to study several aspects of nitrogen metabolism in man. Of the many methods available, the 15 N stable isotope tracer technique holds a special position because the methodology for application and nitrogen isotope analysis is proven and reliable. Valid routine methods using 15 N analysis by emission spectrometry have been demonstrated. Several methods for the preparation of biological material were developed during our participation in the Coordinated Research Programme. In these studies, direct procedures (i.e. use of diluted urine as a samples without chemical preparation) or rapid isolation methods were favoured. Within the scope of the Analytical Quality Control Service (AQCS) enriched stable isotope reference materials for medical and biological studies were prepared and are now available through the International Atomic Energy Agency. The materials are of special importance as the increasing application of stable isotopes as tracers in medical, biological and agricultural studies has focused interest on reliable measurements of biological material of different origin. 24 refs

Approach-Induced Biases in Human Information Sampling.

Directory of Open Access Journals (Sweden)

Laurence T Hunt

2016-11-01

Full Text Available Information sampling is often biased towards seeking evidence that confirms one's prior beliefs. Despite such biases being a pervasive feature of human behavior, their underlying causes remain unclear. Many accounts of these biases appeal to limitations of human hypothesis testing and cognition, de facto evoking notions of bounded rationality, but neglect more basic aspects of behavioral control. Here, we investigated a potential role for Pavlovian approach in biasing which information humans will choose to sample. We collected a large novel dataset from 32,445 human subjects, making over 3 million decisions, who played a gambling task designed to measure the latent causes and extent of information-sampling biases. We identified three novel approach-related biases, formalized by comparing subject behavior to a dynamic programming model of optimal information gathering. These biases reflected the amount of information sampled ("positive evidence approach", the selection of which information to sample ("sampling the favorite", and the interaction between information sampling and subsequent choices ("rejecting unsampled options". The prevalence of all three biases was related to a Pavlovian approach-avoid parameter quantified within an entirely independent economic decision task. Our large dataset also revealed that individual differences in the amount of information gathered are a stable trait across multiple gameplays and can be related to demographic measures, including age and educational attainment. As well as revealing limitations in cognitive processing, our findings suggest information sampling biases reflect the expression of primitive, yet potentially ecologically adaptive, behavioral repertoires. One such behavior is sampling from options that will eventually be chosen, even when other sources of information are more pertinent for guiding future action.

petrography, compositional characteristics and stable isotope ...

African Journals Online (AJOL)

PROF EKWUEME

Subsurface samples of the predominantly carbonate Ewekoro Formation, obtained from Ibese core hole within the Dahomey basin were used in this study. Investigations entail petrographic, elemental composition as well as stable isotopes (carbon and oxygen) geochemistry in order to deduce the different microfacies and ...

Determination of artifactual formation of monomethylmercury (CH{sub 3}Hg{sup +}) in environmental samples using stable Hg{sup 2+} isotopes with ICP-MS detection: Calculation of contents applying species specific isotope addition

Energy Technology Data Exchange (ETDEWEB)

Hintelmann, H. [Trent University, Environmental Science Centre, Peterborough ON K9J 7B8 (Canada); Falter, R. [Bayreuth Institute for Terrestrial Ecosystem Research (BITOEK), Central Analytics, POB 101251, University of Bayreuth, D-95440 Bayreuth (Germany); Ilgen, G. [Bayreuth Institute for Terrestrial Ecosystem Research (BITOEK), Central Analytics, POB 101251, University of Bayreuth, D-95440 Bayreuth (Germany); Evans, R.D. [Trent University, Environmental Science Centre, Peterborough ON K9J 7B8 (Canada)

1997-06-01

Various extraction techniques, as distillation, acid and alkaline extraction, have been tested with regard to their potential to form a monomethylmercury (CH{sub 3}Hg{sup +}) artifact from inorganic Hg during sample preparation. Hg{sup 2+} has been added to different reference materials in the form of enriched stable tracers and the formation of new methylmercury from that tracer has been analyzed by HPLC/ICP-MS and GC/ICP-MS. Both techniques gave comparable results. In particular, the distillation technique was prone to artifact formation. The resulting overestimation of methylmercury in sediments was as high as 80%. Artifact formation in hair, liver and algae samples was less significant, though still observable. Fish muscle tissue showed no artifact formation upon distillation, but some of the inorganic tracer was converted to methylmercury during alkaline extraction. Acid extraction of sediments resulted in low artifact formation rates. Fractionated measurements of sediment distillates revealed high methylmercury formation rates towards the end of the distillation process when acid concentrations in the solution are highest. A technique for correction of the measured apparent methylmercury content applying species specific isotope addition (SSIA) is proposed and the calculation scheme is presented. (orig.). With 6 figs., 3 tabs.

DNA stable-isotope probing (DNA-SIP).

Science.gov (United States)

Dunford, Eric A; Neufeld, Josh D

2010-08-02

DNA stable-isotope probing (DNA-SIP) is a powerful technique for identifying active microorganisms that assimilate particular carbon substrates and nutrients into cellular biomass. As such, this cultivation-independent technique has been an important methodology for assigning metabolic function to the diverse communities inhabiting a wide range of terrestrial and aquatic environments. Following the incubation of an environmental sample with stable-isotope labelled compounds, extracted nucleic acid is subjected to density gradient ultracentrifugation and subsequent gradient fractionation to separate nucleic acids of differing densities. Purification of DNA from cesium chloride retrieves labelled and unlabelled DNA for subsequent molecular characterization (e.g. fingerprinting, microarrays, clone libraries, metagenomics). This JoVE video protocol provides visual step-by-step explanations of the protocol for density gradient ultracentrifugation, gradient fractionation and recovery of labelled DNA. The protocol also includes sample SIP data and highlights important tips and cautions that must be considered to ensure a successful DNA-SIP analysis.

Trophic segregation of a fish assemblage along lateral depth gradients in a subtropical coastal lagoon revealed by stable isotope analyses.

Science.gov (United States)

Mont'Alverne, R; Pereyra, P E R; Garcia, A M

2016-07-01

Stable isotopes were used to evaluate the hypothesis that fish assemblages occurring in shallow and deep areas of a large coastal lagoon are structured in partially segregated trophic modules with consumers showing contrasting reliance on benthic or pelagic food sources. The results revealed that fishes in deep areas were mainly dependent on particulate organic matter in the sediment (SOM), whereas emergent macrophytes were as important as SOM to fish consumers in shallow areas. Conceptual trophic diagrams depicting relationships among basal food sources and consumers in different regions of the lagoon highlighted the greater use of multiple basal food sources by more feeding mode functional guilds in shallow water compared with the use of predominantly benthic resources (SOM) in deep areas. The findings appear to corroborate the initial hypothesis and offer complementary perspectives in understanding the role of spatial ecology in structuring coastal ecosystem function and productivity. © 2016 The Fisheries Society of the British Isles.

Stable, geochemically mediated biospheres in the Deep Mine Microbial Observatory, SD, USA

Science.gov (United States)

Osburn, M. R.; Casar, C. P.; Kruger, B.; Flynn, T. M.

2017-12-01

The terrestrial subsurface is a vast reservoir of life, hosting diverse microbial ecosystems with varying levels of connectivity to surface inputs. Understanding long term ecosystem dynamics within the subsurface biosphere is very challenging due to limitations in accessibility, sample availability, and slow microbial growth rates. The establishment of the Deep Mine Microbial Observatory (DeMMO) at the Sanford Underground Research Facility, SD, USA has allowed for bimonthly sampling for nearly two years at six sites spanning 250 to 1500 m below the surface. Here we present a time-resolved analysis of the geomicrobiology of the six DeMMO sites, which have been created from legacy mine boreholes modified to allow for controlled sampling. Our interdisciplinary approach includes analysis of passively draining fracture fluid for aqueous and gas geochemistry, DNA sequencing, microscopy, and isotopic measurements of organic and inorganic substrates. Fluid geochemistry varies significantly between sites, but is relatively stable over time for a given site, even through significant external perturbations such as drilling and installation of permanent sampling devices into the boreholes. The fluid-hosted microbial diversity follows these trends, with consistent populations present at each site through time, even through drilling events. For instance, the shallowest site (DeMMO 1) consistently hosts >30% uncharacterized phyla and >25% Omnitrophica whereas the deepest site (DeMMO 6) is dominated by Firmicutes and Bacterioidetes. Microbial diversity appears to respond to the availability of energy sources such as organic carbon, sulfate, sulfide, hydrogen, and iron. Carbon isotopic measurements reveal closed system behavior with significant recycling of organic carbon into the DIC pool. Together these observations suggest DeMMO hosts isolated subsurface microbial populations adapted to local geochemistry that are stable on yearlong timescales.

Persistent organic pollutants and stable isotopes in biopsy samples (2004/2006) from Southern Resident killer whales

Energy Technology Data Exchange (ETDEWEB)

Krahn, Margaret M. [NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, WA 98112 (United States)], E-mail: peggy.krahn@noaa.gov; Hanson, M. Bradley [NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, WA 98112 (United States); Baird, Robin W. [Cascadia Research, 218 1/2 W, 4th Avenue, Olympia, WA 98501 (United States); Boyer, Richard H.; Burrows, Douglas G.; Emmons, Candice K. [NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, WA 98112 (United States); Ford, John K.B. [Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC, V9R 5K6 (Canada); Jones, Linda L.; Noren, Dawn P. [NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, WA 98112 (United States); Ross, Peter S. [Fisheries and Oceans Canada, Institute of Ocean Sciences, P.O. Box 6000, Sidney, BC, V8L 4B2 (Canada); Schorr, Gregory S. [Cascadia Research, 218 1/2 W, 4th Avenue, Olympia, WA 98501 (United States); Collier, Tracy K. [NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, WA 98112 (United States)

2007-12-15

'Southern Resident' killer whales include three 'pods' (J, K and L) that reside primarily in Puget Sound/Georgia Basin during the spring, summer and fall. This population was listed as 'endangered' in the US and Canada following a 20% decline between 1996 and 2001. The current study, using blubber/epidermis biopsy samples, contributes contemporary information about potential factors (i.e., levels of pollutants or changes in diet) that could adversely affect Southern Residents. Carbon and nitrogen stable isotopes indicated J- and L-pod consumed prey from similar trophic levels in 2004/2006 and also showed no evidence for a large shift in the trophic level of prey consumed by L-pod between 1996 and 2004/2006. {sigma}PCBs decreased for Southern Residents biopsied in 2004/2006 compared to 1993-1995. Surprisingly, however, a three-year-old male whale (J39) had the highest concentrations of {sigma}PBDEs, {sigma}HCHs and HCB. POP ratio differences between J- and L-pod suggested that they occupy different ranges in winter.

General population exposure of stable lead and 210Pb to residents of New York City

International Nuclear Information System (INIS)

Bogen, D.C.; Welford, G.A.; Morse, R.

1975-12-01

Stable lead and 210 Pb intake, ingestion, and inhalation by residents of New York City were determined. Measurement of excreta samples provided data to establish a mass balance of stable lead and 210 Pb. These results indicate that no more than 5 μg of stable lead and 0.1 pCi of 210 Pb are retained daily by residents of New York City. Analyses of bone samples have provided estimates of the skeletal burden of stable lead and 210 Pb. Using the ICRP model, intake data, and assuming 100 percent skeletal deposition, the calculated stable lead and 210 Pb values are in good agreement with the experimental results. The data indicate that inhalation is the principle source of stable lead to residents in New York City

Ca, Sr and Ba stable isotopes reveal the fate of soil nutrients along a tropical climosequence

Science.gov (United States)

Bullen, Thomas D.; Chadwick, Oliver A.

2016-01-01

Nutrient biolifting is an important pedogenic process in which plant roots obtain inorganic nutrients such as phosphorus (P) and calcium (Ca) from minerals at depth and concentrate those nutrients at the surface. Here we use soil chemistry and stable isotopes of the alkaline earth elements Ca, strontium (Sr) and barium (Ba) to test the hypothesis that biolifting of P has been an important pedogenic process across a soil climosequence developed on volcanic deposits at Kohala Mountain, Hawaii. The geochemical linkage between these elements is revealed as generally positive site-specific relationships in soil mass gains and losses, particularly for P, Ba and Ca, using the ratio of immobile elements titanium and niobium (Ti/Nb) to link individual soil samples to a restricted compositional range of the chemically and isotopically diverse volcanic parent materials. At sites where P is enriched in surface soils relative to abundances in deeper soils, the isotope compositions of exchangeable Ca, Sr and Ba in the shallowest soil horizons ( 10 cm depth) at those sites is consistently heavier than the volcanic parent materials. The isotope compositions of exchangeable Ca and Sr trend toward heavier compositions with depth more gradually, reflecting increasing leakiness from these soils in the order Ba < Sr < Ca and downward transfer of light biocycled Ca and Sr to deeper exchange sites. Given the long-term stability of ecosystem properties at the sites where P is enriched in surface soils, a simple box model demonstrates that persistence of isotopically light exchangeable Ca, Sr and Ba in the shallowest soil horizons requires that the uptake flux to plants from those near-surface layers is less than the recycling flux returned to the surface as litterfall. This observation implicates an uptake flux from an additional source which we attribute to biolifting. We view the heavy exchangeable Ba relative to soil parent values in deeper soils at sites where P is enriched in

Concentration of stable elements in food products

International Nuclear Information System (INIS)

Montford, M.A.; Shank, K.E.; Hendricks, C.; Oakes, T.W.

1980-01-01

Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed

Stable isotope time series and dentin increments elucidate Pleistocene proboscidean paleobiology

Science.gov (United States)

Fisher, Daniel; Rountrey, Adam; Smith, Kathlyn; Fox, David

2010-05-01

Investigations of stable isotope composition of mineralized tissues have added greatly to our knowledge of past climates and dietary behaviors of organisms, even when they are implemented through 'bulk sampling', in which a single assay yields a single, time-averaged value. Likewise, the practice of 'sclerochronology', which documents periodic structural increments comprising a growth record for accretionary tissues, offers insights into rates of growth and age data at a scale of temporal resolution permitted by the nature of structural increments. We combine both of these approaches to analyze dental tissues of late Pleistocene proboscideans. Tusk dentin typically preserves a record of accretionary growth consisting of histologically distinct increments on daily, approximately weekly, and yearly time scales. Working on polished transverse or longitudinal sections, we mill out a succession of temporally controlled dentin samples bounded by clear structural increments with a known position in the sequence of tusk growth. We further subject each sample (or an aliquot thereof) to multiple compositional analyses - most frequently to assess δ18O and δ13C of hydroxyapatite carbonate, and δ13C and δ15N of collagen. This yields, for each animal and each series of years investigated, a set of parallel compositional time series with a temporal resolution of 1-2 months (or finer if we need additional precision). Patterns in variation of thickness of periodic sub-annual increments yield insight into intra-annual and inter-annual variation of tusk growth rate. This is informative even by itself, but it is still more valuable when coupled with compositional time series. Further, the controls on different stable isotope systems are sufficiently different that the data ensemble yields 'much more than the sum of its parts.' By assessing how compositions and growth rates covary, we monitor with greater confidence changes in local climate, diet, behavior, and health status. We

The key microorganisms for anaerobic degradation of pentachlorophenol in paddy soil as revealed by stable isotope probing

Energy Technology Data Exchange (ETDEWEB)

Tong, Hui [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Chengshuai [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550009 (China); Li, Fangbai, E-mail: cefbli@soil.gd.cn [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Luo, Chunling [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chen, Manjia; Hu, Min [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China)

2015-11-15

Highlights: • SIP suggested that Dechloromonas can mineralize PCP in soil. • Methanosaeta and Methanocella acquired PCP-derived carbon. • Lactate enhanced microbial degradation of PCP in soil. - Abstract: Pentachlorophenol (PCP) is a common residual persistent pesticide in paddy soil and has resulted in harmful effect on soil ecosystem. The anaerobic microbial transformation of PCP, therefore, has been received much attentions, especially the functional microbial communities for the reductive transformation. However, the key functional microorganisms for PCP mineralization in the paddy soil still remain unknown. In this work, DNA-based stable isotope probing (SIP) was applied to explore the key microorganisms responsible for PCP mineralization in paddy soil. The SIP results indicated that the dominant bacteria responsible for PCP biodegradation belonged to the genus Dechloromonas of the class β-Proteobacteria. In addition, the increased production of {sup 13}CH{sub 4} and {sup 13}CO{sub 2} indicated that the addition of lactate enhanced the rate of biodegradation and mineralization of PCP. Two archaea classified as the genera of Methanosaeta and Methanocella of class Methanobacteria were enriched in the heavy fraction when with lactate, whereas no archaea was detected in the absence of lactate. These findings provide direct evidence for the species of bacteria and archaea responsible for anaerobic PCP or its breakdown products mineralization and reveal a new insight into the microorganisms linked with PCP degradation in paddy soil.

The key microorganisms for anaerobic degradation of pentachlorophenol in paddy soil as revealed by stable isotope probing

International Nuclear Information System (INIS)

Tong, Hui; Liu, Chengshuai; Li, Fangbai; Luo, Chunling; Chen, Manjia; Hu, Min

2015-01-01

Highlights: • SIP suggested that Dechloromonas can mineralize PCP in soil. • Methanosaeta and Methanocella acquired PCP-derived carbon. • Lactate enhanced microbial degradation of PCP in soil. - Abstract: Pentachlorophenol (PCP) is a common residual persistent pesticide in paddy soil and has resulted in harmful effect on soil ecosystem. The anaerobic microbial transformation of PCP, therefore, has been received much attentions, especially the functional microbial communities for the reductive transformation. However, the key functional microorganisms for PCP mineralization in the paddy soil still remain unknown. In this work, DNA-based stable isotope probing (SIP) was applied to explore the key microorganisms responsible for PCP mineralization in paddy soil. The SIP results indicated that the dominant bacteria responsible for PCP biodegradation belonged to the genus Dechloromonas of the class β-Proteobacteria. In addition, the increased production of 13 CH 4 and 13 CO 2 indicated that the addition of lactate enhanced the rate of biodegradation and mineralization of PCP. Two archaea classified as the genera of Methanosaeta and Methanocella of class Methanobacteria were enriched in the heavy fraction when with lactate, whereas no archaea was detected in the absence of lactate. These findings provide direct evidence for the species of bacteria and archaea responsible for anaerobic PCP or its breakdown products mineralization and reveal a new insight into the microorganisms linked with PCP degradation in paddy soil

Multi-stable perception balances stability and sensitivity

Directory of Open Access Journals (Sweden)

Alexander ePastukhov

2013-03-01

Full Text Available We report that multi-stable perception operates in a consistent, dynamical regime, balancing the conflicting goals of stability and sensitivity. When a multi-stable visual display is viewed continuously, its phenomenal appearance reverses spontaneously at irregular intervals. We characterized the perceptual dynamics of individual observers in terms of four statistical measures: the distribution of dominance times (mean and variance and the novel, subtle dependence on prior history (correlation and time-constant.The dynamics of multi-stable perception is known to reflect several stabilizing and destabilizing factors. Phenomenologically, its main aspects are captured by a simplistic computational model with competition, adaptation, and noise. We identified small parameter volumes (~3% of the possible volume in which the model reproduced both dominance distribution and history-dependence of each observer. For 21 of 24 data sets, the identified volumes clustered tightly (~15% of the possible volume, revealing a consistent `operating regime' of multi-stable perception. The `operating regime' turned out to be marginally stable or, equivalently, near the brink of an oscillatory instability. The chance probability of the observed clustering was <0.02.To understand the functional significance of this empirical `operating regime', we compared it to the theoretical `sweet spot' of the model. We computed this `sweet spot' as the intersection of the parameter volumes in which the model produced stable perceptual outcomes and in which it was sensitive to input modulations. Remarkably, the empirical `operating regime' proved to be largely coextensive with the theoretical `sweet spot'. This demonstrated that perceptual dynamics was not merely consistent but also functionally optimized (in that it balances stability with sensitivity. Our results imply that multi-stable perception is not a laboratory curiosity, but reflects a functional optimization of perceptual

High Precision Zinc Stable Isotope Measurement of Certified Biological Reference Materials Using the Double Spike Technique and Multiple Collector-ICP-MS.

Science.gov (United States)

Moore, Rebekah E T; Larner, Fiona; Coles, Barry J; Rehkämper, Mark

2017-04-01

Biological reference materials with well-characterised stable isotope compositions are lacking in the field of 'isotope biochemistry', which seeks to understand bodily processes that rely on essential metals by determining metal stable isotope ratios. Here, we present Zn stable isotope data for six biological reference materials with certified trace metal concentrations: fish muscle, bovine muscle, pig kidney, human hair, human blood serum and human urine. Replicate analyses of multiple aliquots of each material achieved reproducibilities (2sd) of 0.04-0.13‰ for δ 66/64 Zn (which denotes the deviation of the 66 Zn/ 64 Zn ratio of a sample from a pure Zn reference material in parts per 1000). This implies only very minor isotopic heterogeneities within the samples, rendering them suitable as quality control materials for Zn isotope analyses. This endorsement is reinforced by (i) the close agreement of our Zn isotope data for two of the samples (bovine muscle and human blood serum) to previously published results for different batches of the same material and (ii) the similarity of the isotopic data for the samples (δ 66/64 Zn ≈ -0.8 to 0.0‰) to previously published Zn isotope results for similar biological materials. Further tests revealed that the applied Zn separation procedure is sufficiently effective to enable accurate data acquisition even at low mass resolving power (M/ΔM ≈ 400), as measurements and analyses conducted at much higher mass resolution (M/ΔM ≈ 8500) delivered essentially identical results.

Groundwater Recharge Processes Revealed By Multi-Tracers Approach in a Headwater, North China Plain

Science.gov (United States)

Sakakibara, K.; Tsujimura, M.; Song, X.; Zhang, J.

2014-12-01

Groundwater recharge variation in space and time is crucial for effective water management especially in arid/ semi-arid regions. In order to reveal comprehensive groundwater recharge processes in a catchment with a large topographical relief and seasonal hydrological variations, intensive field surveys were conducted at 4 times in different seasons in Wangkuai watershed, Taihang Mountains, which is a main groundwater recharge zone of North China Plain. The groundwater, spring, stream water and lake water were sampled, and inorganic solute constituents and stable isotopes of oxygen-18 and deuterium were determined on all water samples. Also, the stream flow rate was observed in stable state condition. The stable isotopic compositions, silica and bicarbonate concentrations in the groundwater show close values as those in the surface water, suggesting main groundwater recharge occurs from surface water at mountain-plain transitional zone throughout a year. Also, the deuterium and oxgen-18 in the Wangkuai reservoir and the groundwater in the vicinity of the reservoir show higher values, suggesting the reservoir water, affected by evaporation effect, seems to have an important role for the groundwater recharge in alluvial plain. For specifying the groundwater recharge area and quantifying groundwater recharge rate from the reservoir, an inversion analysis and a simple mixing model were applied in Wangkuai watershed using stable isotopes of oxygen-18 and deuterium. The model results show that groundwater recharge occurs dominantly at the altitude from 357 m to 738 m corresponding to mountain-plain transitional zone, and groundwater recharge rate by Wangkuai reservoir is estimated to be 2.4 % of total groundwater recharge in Wangkuai watershed.

Titanium stable isotope investigation of magmatic processes on the Earth and Moon

Science.gov (United States)

Millet, Marc-Alban; Dauphas, Nicolas; Greber, Nicolas D.; Burton, Kevin W.; Dale, Chris W.; Debret, Baptiste; Macpherson, Colin G.; Nowell, Geoffrey M.; Williams, Helen M.

2016-09-01

We present titanium stable isotope measurements of terrestrial magmatic samples and lunar mare basalts with the aims of constraining the composition of the lunar and terrestrial mantles and evaluating the potential of Ti stable isotopes for understanding magmatic processes. Relative to the OL-Ti isotope standard, the δ49Ti values of terrestrial samples vary from -0.05 to +0.55‰, whereas those of lunar mare basalts vary from -0.01 to +0.03‰ (the precisions of the double spike Ti isotope measurements are ca. ±0.02‰ at 95% confidence). The Ti stable isotope compositions of differentiated terrestrial magmas define a well-defined positive correlation with SiO2 content, which appears to result from the fractional crystallisation of Ti-bearing oxides with an inferred isotope fractionation factor of ΔTi49oxide-melt = - 0.23 ‰ ×106 /T2. Primitive terrestrial basalts show no resolvable Ti isotope variations and display similar values to mantle-derived samples (peridotite and serpentinites), indicating that partial melting does not fractionate Ti stable isotopes and that the Earth's mantle has a homogeneous δ49Ti composition of +0.005 ± 0.005 (95% c.i., n = 29). Eclogites also display similar Ti stable isotope compositions, suggesting that Ti is immobile during dehydration of subducted oceanic lithosphere. Lunar basalts have variable δ49Ti values; low-Ti mare basalts have δ49Ti values similar to that of the bulk silicate Earth (BSE) while high-Ti lunar basalts display small enrichment in the heavy Ti isotopes. This is best interpreted in terms of source heterogeneity resulting from Ti stable isotope fractionation associated with ilmenite-melt equilibrium during the generation of the mantle source of high-Ti lunar mare basalts. The similarity in δ49Ti between terrestrial samples and low-Ti lunar basalts provides strong evidence that the Earth and Moon have identical stable Ti isotope compositions.

Elemental and stable isotopic approaches for studying the organic and inorganic carbon components in natural samples

International Nuclear Information System (INIS)

Helie, J-F

2009-01-01

The carbon cycle is an important part of major biogeochemical cycles. Many techniques may be used to characterize carbon amounts and sources in the environment. Here we first review the most popular techniques for the determination of organic and inorganic carbon concentrations. Decarbonatation techniques are also reviewed in details since it is often an important part of organic carbon analysis. The second part of this paper addresses the use of carbon stable isotopes to characterize organic carbon sources and processes in the environment. An overview of general stable isotopes background and terminology is given as well as the most popular analytical techniques.

SIMPLE ESTIMATOR AND CONSISTENT STRONGLY OF STABLE DISTRIBUTIONS

Directory of Open Access Journals (Sweden)

Cira E. Guevara Otiniano

2016-06-01

Full Text Available Stable distributions are extensively used to analyze earnings of financial assets, such as exchange rates and stock prices assets. In this paper we propose a simple and strongly consistent estimator for the scale parameter of a symmetric stable L´evy distribution. The advantage of this estimator is that your computational time is minimum thus it can be used to initialize intensive computational procedure such as maximum likelihood. With random samples of sized n we tested the efficacy of these estimators by Monte Carlo method. We also included applications for three data sets.

Platinum stable isotope ratio measurements by double-spike multiple collector ICPMS

DEFF Research Database (Denmark)

Creech, John; Baker, Joel; Handler, Monica

2013-01-01

We present a new technique for the precise determination of platinum (Pt) stable isotope ratios by multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS) using two different Pt double-spikes ( Pt-Pt and Pt-Pt). Results are expressed relative to the IRMM-010 Pt isotope standard......) can be obtained on Pt stable isotope ratios with either double-spike. Elemental doping tests reveal that double-spike corrected Pt stable isotope ratios are insensitive to the presence of relatively high (up to 10%) levels of matrix elements, although the Pt-Pt double-spike is affected by an isobaric...... = 7.308%) results in a redefined Pt atomic weight of 195.08395 ± 0.00068. Using our technique we have measured small, reproducible and statistically significant offsets in Pt stable isotope ratios between different Pt element standards and the IRMM-010 standard, which potentially indicates...

Chemical synthesis of highly stable PVA/PANI films for supercapacitor application

Energy Technology Data Exchange (ETDEWEB)

Patil, D.S.; Shaikh, J.S.; Dalavi, D.S.; Kalagi, S.S. [Thin Films Materials laboratory, Department of Physics, Shivaji University, Kolhapur 416004, M.S. (India); Patil, P.S., E-mail: psp_phy@unishivaji.ac.in [Thin Films Materials laboratory, Department of Physics, Shivaji University, Kolhapur 416004, M.S. (India)

2011-08-15

Highlights: {yields} Chemical synthesis of PVA/PANI films by spin and dip coating at room temperature. {yields} Thickness dependent supercapacitor behavior of PVA/PANI film. {yields} The synthesized film are highly stable up to 20,000 cycles. - Abstract: Polyvinyl alcohol (PVA)/polyaniline (PANI) thin films were chemically synthesized by adopting two step process: initially a thin layer (200 nm) of PVA was spin coated by using an aqueous PVA solution onto fluorine doped tin oxide (FTO) coated glass substrate, afterwards PANI was chemically polymerized from aniline monomer and dip coated onto the precoated substrate. The thickness of PANI layer was varied from 293 nm to 2367 nm by varying deposition cycles onto the precoated PVA thin film. The resultant PVA/PANI films were characterized for their optical, morphological and electrochemical properties. The FT-IR and Raman spectra revealed characteristic features of the PANI phase. The SEM study showed porous spongy structure. Electrochemical properties were studied by electrochemical impedance measurement and cyclic voltammetry. The electrochemical performance of PVA/PANI thin films was investigated in 1 M H{sub 2}SO{sub 4} aqueous electrolyte. The highest specific capacitance of 571 Fg{sup -1} was observed for the optimized thickness of 880 nm. The film was found to be stable for more than 20,000 cycles. The samples degraded slightly (25% decrement in specific capacitance) for the first 10,000 cycles. The degradation becomes much slower (10.8% decrement in specific capacitance) beyond 10,000 cycles. This dramatic improvement in the electrochemical stability of the PANI samples, without sacrificing specific capacitance was attributed to the optimized PVA layer.

Nullspace Sampling with Holonomic Constraints Reveals Molecular Mechanisms of Protein Gαs.

Directory of Open Access Journals (Sweden)

Dimitar V Pachov

2015-07-01

Full Text Available Proteins perform their function or interact with partners by exchanging between conformational substates on a wide range of spatiotemporal scales. Structurally characterizing these exchanges is challenging, both experimentally and computationally. Large, diffusional motions are often on timescales that are difficult to access with molecular dynamics simulations, especially for large proteins and their complexes. The low frequency modes of normal mode analysis (NMA report on molecular fluctuations associated with biological activity. However, NMA is limited to a second order expansion about a minimum of the potential energy function, which limits opportunities to observe diffusional motions. By contrast, kino-geometric conformational sampling (KGS permits large perturbations while maintaining the exact geometry of explicit conformational constraints, such as hydrogen bonds. Here, we extend KGS and show that a conformational ensemble of the α subunit Gαs of heterotrimeric stimulatory protein Gs exhibits structural features implicated in its activation pathway. Activation of protein Gs by G protein-coupled receptors (GPCRs is associated with GDP release and large conformational changes of its α-helical domain. Our method reveals a coupled α-helical domain opening motion while, simultaneously, Gαs helix α5 samples an activated conformation. These motions are moderated in the activated state. The motion centers on a dynamic hub near the nucleotide-binding site of Gαs, and radiates to helix α4. We find that comparative NMA-based ensembles underestimate the amplitudes of the motion. Additionally, the ensembles fall short in predicting the accepted direction of the full activation pathway. Taken together, our findings suggest that nullspace sampling with explicit, holonomic constraints yields ensembles that illuminate molecular mechanisms involved in GDP release and protein Gs activation, and further establish conformational coupling between key

Analysis of stable isotope assisted metabolomics data acquired by GC-MS

International Nuclear Information System (INIS)

Wei, Xiaoli; Shi, Biyun; Koo, Imhoi; Yin, Xinmin; Lorkiewicz, Pawel; Suhail, Hamid; Rattan, Ramandeep; Giri, Shailendra; McClain, Craig J.

2017-01-01

Stable isotope assisted metabolomics (SIAM) measures the abundance levels of metabolites in a particular pathway using stable isotope tracers (e.g., 13 C, 18 O and/or 15 N). We report a method termed signature ion approach for analysis of SIAM data acquired on a GC-MS system equipped with an electron ionization (EI) ion source. The signature ion is a fragment ion in EI mass spectrum of a derivatized metabolite that contains all atoms of the underivatized metabolite, except the hydrogen atoms lost during derivatization. In this approach, GC-MS data of metabolite standards were used to recognize the signature ion from the EI mass spectra acquired from stable isotope labeled samples, and a linear regression model was used to deconvolute the intensity of overlapping isotopologues. A mixture score function was also employed for cross-sample chromatographic peak list alignment to recognize the chromatographic peaks generated by the same metabolite in different samples, by simultaneously evaluating the similarity of retention time and EI mass spectrum of two chromatographic peaks. Analysis of a mixture of 16 13 C-labeled and 16 unlabeled amino acids showed that the signature ion approach accurately identified and quantified all isotopologues. Analysis of polar metabolite extracts from cells respectively fed with uniform 13 C-glucose and 13 C-glutamine further demonstrated that this method can also be used to analyze the complex data acquired from biological samples. - Highlights: • A signature ion approach is developed for analysis of stable isotope GC-MS data. • GC-MS data of compound standards are used for selection of the signature ion. • Linear regression model is used to deconvolute the overlapping isotopologue peaks. • The developed method was tested by known compounds and biological samples.

Methodologies for extraction of dissolved inorganic carbon for stable carbon isotope studies : evaluation and alternatives

Science.gov (United States)

Hassan, Afifa Afifi

1982-01-01

The gas evolution and the strontium carbonate precipitation techniques to extract dissolved inorganic carbon (DIC) for stable carbon isotope analysis were investigated. Theoretical considerations, involving thermodynamic calculations and computer simulation pointed out several possible sources of error in delta carbon-13 measurements of the DIC and demonstrated the need for experimental evaluation of the magnitude of the error. An alternative analytical technique, equilibration with out-gassed vapor phase, is proposed. The experimental studies revealed that delta carbon-13 of the DIC extracted from a 0.01 molar NaHC03 solution by both techniques agreed within 0.1 per mil with the delta carbon-13 of the DIC extracted by the precipitation technique, and an increase of only 0.27 per mil in that extracted by the gas evolution technique. The efficiency of extraction of DIC decreased with sulfate concentration in the precipitation technique but was independent of sulfate concentration in the gas evolution technique. Both the precipitation and gas evolution technique were found to be satisfactory for extraction of DIC from different kinds of natural water for stable carbon isotope analysis, provided appropriate precautions are observed in handling the samples. For example, it was found that diffusion of atmospheric carbon dioxide does alter the delta carbon-13 of the samples contained in polyethylene bottles; filtration and drying in the air change the delta carbon-13 of the samples contained in polyethylene bottles; filtration and drying in the air change the delta carbon-13 of the precipitation technique; hot manganese dioxide purification changes the delta carbon-13 of carbon dioxide. (USGS)

Bias-corrected estimation of stable tail dependence function

DEFF Research Database (Denmark)

Beirlant, Jan; Escobar-Bach, Mikael; Goegebeur, Yuri

2016-01-01

We consider the estimation of the stable tail dependence function. We propose a bias-corrected estimator and we establish its asymptotic behaviour under suitable assumptions. The finite sample performance of the proposed estimator is evaluated by means of an extensive simulation study where...

Stable isotopes

International Nuclear Information System (INIS)

Evans, D.K.

1986-01-01

Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

The effect of air stable n-doping through mild plasma on the mechanical property of WSe2 layers

Science.gov (United States)

Xu, Linyan; Qian, Shuangbei; Xie, Yuan; Wu, Enxiu; Hei, Haicheng; Feng, Zhihong; Wu, Sen; Hu, Xiaodong; Guo, Tong; Zhang, Daihua

2018-04-01

Two-dimensional transition metal dichalcogenides have been widely applied to electronic and optoelectronic device owing to their remarkable material properties. Many studies present the platform for regulating the contact resistance via various doping schemes. Here, we report the alteration of mechanical properties of few top layers of the WSe2 flake which are processed by air stable n-doping of N2O with a constant gas flow through mild plasma and present better manufacturability and friability. The single-line nanoscratching experiments on the WSe2 flakes with different doping time reveal that the manufacturable depths are positively correlated with the exposure time at a certain range and tend to be stable afterwards. Meanwhile, material characterization by x-ray photoelectron spectroscopy confirms that the alteration of mechanical properties is owing to the creation of Se vacancies and substitution of O atoms, which breaks the primary molecular structure of the WSe2 flakes. The synchronous Kelvin probe force microscopy and topography results of ROI nanoscratching of a stepped WSe2 sample confirmed that the depth of the degenerate doping is five layers, which was consistent with the single-line scratching experiments. Our results reveal the interrelationship of the mechanical property, chemical bonds and work function changes of the doped WSe2 flakes.

MR imaging of stable posttraumatic spinal cord injury

International Nuclear Information System (INIS)

Braun, I.F.; Hoffman, J.C. Jr.; Murphy, C.; Davis, P.C.

1986-01-01

Posttraumatic spinal cord cysts have been thought to be infrequent sequelae of spinal trauma. To evaluate the incidence of spinal cord abnormalities in patients who have previously sustained cord trauma, the authors studied the incidence of these changes in clinically stable patients following injury. Twenty-five patients with a history of previous cord injury and stable neurologic status volunteered for MR imaging studies. Studies performed using a 0.5-T and 1.5-T unit revealed focal kinking of the cord at the trauma site as well as intramedullary hypointense areas on T1-weighted images in most volunteers. There was close clinical correlation between MR imaging findings and experimental pathologic data, which suggests that these lesions are much more prevalent than once thought

Development of a non-destructive micro-analytical method for stable carbon isotope analysis of transmission electron microscope (TEM) samples

Energy Technology Data Exchange (ETDEWEB)

Hode, Tomas [Department of Geology, Portland State University, Portland, P.O. Box 751, OR 97201 (United States)], E-mail: hode@pdx.edu; Kristiansson, Per; Elfman, Mikael [Division of Nuclear Physics, Department of Physics, Lund Institute of Technology, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Hugo, Richard C.; Cady, Sherry L. [Department of Geology, Portland State University, Portland, P.O. Box 751, OR 97201 (United States)

2009-10-01

The biogenicity of ancient morphological microfossil-like objects can be established by linking morphological (e.g. cell remnants and extracellular polymeric matrix) and chemical (e.g. isotopes, biomarkers and biominerals) evidence indicative of microorganisms or microbial activity. We have developed a non-destructive micro-analytical ion beam system capable of measuring with high spatial resolution the stable carbon isotope ratios of thin samples used for transmission electron microscopy. The technique is based on elastic scattering of alpha particles with an energy of 2.751 MeV. At this energy the {sup 13}C cross section is enhanced relative to the pure Rutherford cross section for {sup 13}C, whereas the {sup 12}C cross section is reduced relative to its pure Rutherford cross section. Here we report the initial results of this experimental approach used to characterize ultramicrotomed sections of sulfur-embedded graphite and microbial cells.

Synthesis and Photophysical Characterizations of Thermal -Stable Naphthalene Benzimidazoles

OpenAIRE

Erten Ela, Şule; Özçelik, Serdar; Eren, Ersin

2011-01-01

Microwave-assisted synthesis, photophysical and electrochemical properties of thermal-stable naphthalene benzimidazoles and naphthalimides are studied in this paper. Microwave-assisted synthesis of naphthalene benzimidazoles provide higher yields than the conventional thermal synthesis. Comparative photophysical properties of naphthalene benzimidazoles and naphthalimides are revealed that conjugation of electron-donating group onto naphthalimide moiety increases fluorescence ...

Stable-carbon isotope variability in tree foliage and wood

International Nuclear Information System (INIS)

Leavitt, S.W.; Long, A.

1986-01-01

This study documents variation of stable-carbon isotope ratios ( 13 C/ 12 C) in trees of genera Juniperus and Pinus under field conditions. Results are from cellulose analysis on leaves, twigs, and wood from a number of localities in the southwestern US. Substantial variability, typically 1-3%, exists among leaves, within wood (radially, vertically, circumferentially), and between individuals at a site. These results may help guide sampling in tracer-type studies with stable-carbon isotope ratios and aid in the interpretation of isotopic results from such studies

Identification of trophic interactions within an estuarine food web (northern New Zealand) using fatty acid biomarkers and stable isotopes

Science.gov (United States)

Alfaro, Andrea C.; Thomas, François; Sergent, Luce; Duxbury, Mark

2006-10-01

Fatty acid biomarkers and stable isotope signatures were used to identify the trophic dynamics of a mangrove/seagrass estuarine food web at Matapouri, northern New Zealand. Specific fatty acids were used to identify the preferred food sources (i.e., mangroves, seagrass, phytoplankton, macroalgae, bacteria, and zooplankton) of dominant fauna (i.e., filter feeders, grazing snails, scavenger/predatory snails, shrimp, crabs, and fish), and their presence in water and sediment samples throughout the estuary. The diets of filter feeders were found to be dominated by dinoflagellates, whereas grazers showed a higher diatom contribution. Bacteria associated with organic debris on surface sediments and brown algal ( Hormosira banksii) material in the form of suspended organic matter also accounted for a high proportion of most animal diets. Animals within higher trophic levels had diverse fatty acid profiles, revealing their varied feeding strategies and carbon sources. The stable isotope (δ 13C and δ 15N) analyses of major primary producers and consumers/predators revealed a trend of 15N enrichment with increasing trophic level, while δ 13C values provided a generally good description of carbon flow through the food web. Overall results from both fatty acid profiles and stable isotopes indicate that a variety of carbon sources with a range of trophic pathways typify this food web. Moreover, none of the animals studied was dependent on a single food source. This study is the first to use a comprehensive fatty acid biomarker and stable isotope approach to investigate the food web dynamics within a New Zealand temperate mangrove/seagrass estuary. This quantitative research may contribute to the currently developing management strategies for estuaries in northern New Zealand, especially for those perceived to have expanding mangrove fringes.

stableGP

Data.gov (United States)

National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

Differential soil water sourcing of managed Loblolly Pine and Sweet Gum revealed by stable isotopes in the Upper Coastal Plain, USA

Science.gov (United States)

Brockman, L. E.; Younger, S. E.; Jackson, C. R.; McDonnell, J.; Janzen, K. F.

2017-12-01

Stable isotope signatures of stem water can illuminate where in the soil profile different types of trees are accessing soil water and thereby contribute to our understanding of water movement through the soil plant atmosphere continuum. The objective of this study was to use 2H and 18O isotopes to characterize water sources of fourteen-year-old intensively managed Loblolly Pine and Sweet Gum stands in replicated (n=3) paired plots. In order to differentiate the isotopic signatures of tree and soil water, both species and five soil depths were sampled monthly for one year. Tree sap and soil water were extracted cryogenically and their isotopic signatures were determined. Although plant water uptake is generally considered a non-fractionating process, our dataset suggests a source of fractionation in 2H signatures in both species and during most of the thirteen sampling events. As a result, only the 18O isotopic data were used to determine the vertical distribution of soil water contributions to stem water. Statistically, we grouped the five soil sampling depths into three isotopic horizons. Shallow, intermediate and deep soil represent sampling depths of 0-10cm, 30-70cm and 100-125cm, respectively. These isotopic horizons were used in a direct inference approach and Bayesian mixing model analysis to determine the origin of stem water. In this study, Loblolly Pine used more water from intermediate and deep soil while Sweet Gum used more water from shallow and intermediate soil. In the winter months, January through March, Loblolly Pine transpired primarily deep soil where as Sweet Gum mainly utilized shallow soil for transpiration. These results indicate that both species have opportunistic water use patterns with seasonal variation.

Repeat synoptic sampling reveals drivers of change in carbon and nutrient chemistry of Arctic catchments

Science.gov (United States)

Zarnetske, J. P.; Abbott, B. W.; Bowden, W. B.; Iannucci, F.; Griffin, N.; Parker, S.; Pinay, G.; Aanderud, Z.

2017-12-01

Dissolved organic carbon (DOC), nutrients, and other solute concentrations are increasing in rivers across the Arctic. Two hypotheses have been proposed to explain these trends: 1. distributed, top-down permafrost degradation, and 2. discrete, point-source delivery of DOC and nutrients from permafrost collapse features (thermokarst). While long-term monitoring at a single station cannot discriminate between these mechanisms, synoptic sampling of multiple points in the stream network could reveal the spatial structure of solute sources. In this context, we sampled carbon and nutrient chemistry three times over two years in 119 subcatchments of three distinct Arctic catchments (North Slope, Alaska). Subcatchments ranged from 0.1 to 80 km2, and included three distinct types of Arctic landscapes - mountainous, tundra, and glacial-lake catchments. We quantified the stability of spatial patterns in synoptic water chemistry and analyzed high-frequency time series from the catchment outlets across the thaw season to identify source areas for DOC, nutrients, and major ions. We found that variance in solute concentrations between subcatchments collapsed at spatial scales between 1 to 20 km2, indicating a continuum of diffuse- and point-source dynamics, depending on solute and catchment characteristics (e.g. reactivity, topography, vegetation, surficial geology). Spatially-distributed mass balance revealed conservative transport of DOC and nitrogen, and indicates there may be strong in-stream retention of phosphorus, providing a network-scale confirmation of previous reach-scale studies in these Arctic catchments. Overall, we present new approaches to analyzing synoptic data for change detection and quantification of ecohydrological mechanisms in ecosystems in the Arctic and beyond.

A highly stable microchannel heat sink for convective boiling

International Nuclear Information System (INIS)

Lu, Chun Ting; Pan Chin

2009-01-01

To develop a highly stable two-phase microchannel heat sink, we experimented with convective boiling in diverging, parallel microchannels with different distributions of laser-etched artificial nucleation sites. Each microchannel had a mean hydraulic diameter of 120 µm. The two-phase flow visualization and the magnitudes of pressure drop and inlet temperature oscillations under boiling conditions demonstrated clearly the merits of using artificial nucleation sites to further stabilize the flow boiling in diverging, parallel microchannels. The stability map showed the plane of subcooling number versus phase change number. It illustrated that diverging, parallel microchannels with artificial nucleation cavities have a much wider stable region than parallel microchannels with uniform cross-sections or diverging, parallel microchannels without artificial nucleation cavities. In addition, the results revealed that the design with cavities distributed uniformly along the downstream half of the channel presented the best stability performance among the three distributions of nucleation sites. This particular design can be regarded as a highly stable microchannel heat sink for convective boiling

Dynamics and control of twisting bi-stable structures

Science.gov (United States)

Arrieta, Andres F.; van Gemmeren, Valentin; Anderson, Aaron J.; Weaver, Paul M.

2018-02-01

Compliance-based morphing structures have the potential to offer large shape adaptation, high stiffness and low weight, while reducing complexity, friction, and scalability problems of mechanism based systems. A promising class of structure that enables these characteristics are multi-stable structures given their ability to exhibit large deflections and rotations without the expensive need for continuous actuation, with the latter only required intermittently. Furthermore, multi-stable structures exhibit inherently fast response due to the snap-through instability governing changes between stable states, enabling rapid configuration switching between the discrete number of programmed shapes of the structure. In this paper, the design and utilisation of the inherent nonlinear dynamics of bi-stable twisting I-beam structures for actuation with low strain piezoelectric materials is presented. The I-beam structure consists of three compliant components assembled into a monolithic single element, free of moving parts, and showing large deflections between two stable states. Finite element analysis is utilised to uncover the distribution of strain across the width of the flange, guiding the choice of positioning for piezoelectric actuators. In addition, the actuation authority is maximised by calculating the generalised coupling coefficient for different positions of the piezoelectric actuators. The results obtained are employed to tailor and test I-beam designs exhibiting desired large deflection between stable states, while still enabling the activation of snap-through with the low strain piezoelectric actuators. To this end, the dynamic response of the I-beams to piezoelectric excitation is investigated, revealing that resonant excitations are insufficient to dynamically trigger snap-through. A novel bang-bang control strategy, which exploits the nonlinear dynamics of the structure successfully triggers both single and constant snap-through between the stable states

An Investigation into the Relationship Between Distillate Yield and Stable Isotope Fractionation

Science.gov (United States)

Sowers, T.; Wagner, A. J.

2016-12-01

Recent breakthroughs in laser spectrometry have allowed for faster, more efficient analyses of stable isotopic ratios in water samples. Commercially available instruments from Los Gatos Research and Picarro allow users to quickly analyze a wide range of samples, from seawater to groundwater, with accurate isotope ratios of D/H to within ± 0.2 ‰ and 18O/16O to within ± 0.03 ‰. While these instruments have increased the efficiency of stable isotope laboratories, they come with some major limitations, such as not being able to analyze hypersaline waters. The Los Gatos Research Liquid Water Isotope Analyzer (LWIA) can accurately and consistently measure the stable isotope ratios in waters with salinities ranging from 0 to 4 grams per liter (0 to 40 parts per thousand). In order to analyze water samples with salinities greater than 4 grams per liter, however, it was necessary to develop a consistent method through which to reduce salinity while causing as little fractionation as possible. Using a consistent distillation method, predictable fractionation of δ 18O and δ 2 H values was found to occur. This fractionation occurs according to a linear relationship with respect to the percent yield of the water in the sample. Using this method, samples with high salinity can be analyzed using laser spectrometry instruments, thereby enabling laboratories with Los Gatos or Picarro instruments to analyze those samples in house without having to dilute them using labor-intensive in-house standards or expensive premade standards.

New stable phase in binary Fe-Nd

International Nuclear Information System (INIS)

Schneider, G.; Landgraf, F.J.G.; Villas-Boas, V.; Bezerra, G.H.; Missell, F.P.; Ray, A.E.

1992-01-01

An investigation of binary Fe-Nd alloys revealed the existence of an oxygen-free, stable Fe-rich phase A 2 , formed peritecticly in the range 750-800 deg C. EPMA shows this phase to contain 22.8 atomic percent Nd. This ferromagnetic phase has T c = 230 de C, but is magnetically soft. The X-ray diffraction pattern can be indexed using a hexagonal cell with a = 2.021 nm. and c = 1.235 nm. (author)

Respondent-Driven Sampling – Testing Assumptions: Sampling with Replacement

Directory of Open Access Journals (Sweden)

Barash Vladimir D.

2016-03-01

Full Text Available Classical Respondent-Driven Sampling (RDS estimators are based on a Markov Process model in which sampling occurs with replacement. Given that respondents generally cannot be interviewed more than once, this assumption is counterfactual. We join recent work by Gile and Handcock in exploring the implications of the sampling-with-replacement assumption for bias of RDS estimators. We differ from previous studies in examining a wider range of sampling fractions and in using not only simulations but also formal proofs. One key finding is that RDS estimates are surprisingly stable even in the presence of substantial sampling fractions. Our analyses show that the sampling-with-replacement assumption is a minor contributor to bias for sampling fractions under 40%, and bias is negligible for the 20% or smaller sampling fractions typical of field applications of RDS.

Stable isotope dimethyl labelling for quantitative proteomics and beyond

Science.gov (United States)

Hsu, Jue-Liang; Chen, Shu-Hui

2016-01-01

Stable-isotope reductive dimethylation, a cost-effective, simple, robust, reliable and easy-to- multiplex labelling method, is widely applied to quantitative proteomics using liquid chromatography-mass spectrometry. This review focuses on biological applications of stable-isotope dimethyl labelling for a large-scale comparative analysis of protein expression and post-translational modifications based on its unique properties of the labelling chemistry. Some other applications of the labelling method for sample preparation and mass spectrometry-based protein identification and characterization are also summarized. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644970

Forensic Applications of Light-Element Stable Isotope Ratios of Ricinus communis Seeds and Ricin Preparations

Energy Technology Data Exchange (ETDEWEB)

Kreuzer, Helen W.; West, Jason B.; Ehleringer, James

2013-01-01

Seeds of the castor plant Ricinus communis, also known as castor beans, are of forensic interest because they are the source of the poison ricin. We have tested whether stable isotope ratios of castor seeds and ricin prepared by various methods can be used as a forensic signature. We collected over 300 castor seed samples from locations around the world and measured the C, N, O, and H stable isotope ratios of the whole seeds, oil, and three types of ricin preparations. Our results demonstrate that N isotope ratios can be used to correlate ricin prepared by any of these methods to source seeds. Further, stable isotope ratios distinguished >99% of crude and purified ricin protein samples in pair-wise comparison tests. Stable isotope ratios therefore constitute a valuable forensic signature for ricin preparations.

A manual for a Laboratory Information Management System (LIMS) for light stable isotopes

Science.gov (United States)

Coplen, Tyler B.

1998-01-01

The reliability and accuracy of isotopic data can be improved by utilizing database software to (i) store information about samples, (ii) store the results of mass spectrometric isotope-ratio analyses of samples, (iii) calculate analytical results using standardized algorithms stored in a database, (iv) normalize stable isotopic data to international scales using isotopic reference materials, and (v) generate multi-sheet paper templates for convenient sample loading of automated mass-spectrometer sample preparation manifolds. Such a database program is presented herein. Major benefits of this system include (i) an increase in laboratory efficiency, (ii) reduction in the use of paper, (iii) reduction in workload due to the elimination or reduction of retyping of data by laboratory personnel, and (iv) decreased errors in data reported to sample submitters. Such a database provides a complete record of when and how often laboratory reference materials have been analyzed and provides a record of what correction factors have been used through time. It provides an audit trail for stable isotope laboratories. Since the original publication of the manual for LIMS for Light Stable Isotopes, the isotopes 3 H, 3 He, and 14 C, and the chlorofluorocarbons (CFCs), CFC-11, CFC-12, and CFC-113, have been added to this program.

Direct numerical simulation of stable and unstable turbulent thermal boundary layers

International Nuclear Information System (INIS)

Hattori, Hirofumi; Houra, Tomoya; Nagano, Yasutaka

2007-01-01

This paper presents direct numerical simulations (DNS) of stable and unstable turbulent thermal boundary layers. Since a buoyancy-affected boundary layer is often encountered in an urban environmental space where stable and unstable stratifications exist, exploring a buoyancy-affected boundary layer is very important to know the transport phenomena of the flow in an urban space. Although actual observation may qualitatively provide the characteristics of these flows, the relevant quantitative turbulent quantities are very difficult to measure. Thus, in order to quantitatively investigate a buoyancy-affected boundary layer in detail, we have here carried out for the first time time- and space-developing DNS of slightly stable and unstable turbulent thermal boundary layers. The DNS results show the quantitative turbulent statistics and structures of stable and unstable thermal boundary layers, in which the characteristic transport phenomena of thermally stratified boundary layers are demonstrated by indicating the budgets of turbulent shear stress and turbulent heat flux. Even though the input of buoyant force is not large, the influence of buoyancy is clearly revealed in both stable and unstable turbulent boundary layers. In particular, it is found that both stable and unstable thermal stratifications caused by the weak buoyant force remarkably alter the structure of near-wall turbulence

Preparation of thermally stable nanocrystalline hydroxyapatite by hydrothermal method.

Science.gov (United States)

Prakash Parthiban, S; Elayaraja, K; Girija, E K; Yokogawa, Y; Kesavamoorthy, R; Palanichamy, M; Asokan, K; Narayana Kalkura, S

2009-12-01

Thermally stable hydroxyapatite (HAp) was synthesized by hydrothermal method in the presence of malic acid. X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), differential thermal analysis (DTA), thermogravimetric analysis (TGA) was done on the synthesized powders. These analyses confirmed the sample to be free from impurities and other phases of calcium phosphates, and were of rhombus morphology along with nanosized particles. IR and Raman analyses indicated the adsorption of malic acid on HAp. Thermal stability of the synthesized HAp was confirmed by DTA and TGA. The synthesized powders were thermally stable upto 1,400 degrees C and showed no phase change. The proposed method might be useful for producing thermally stable HAp which is a necessity for high temperature coating applications.

Measurement of organic carbon stable isotope composition of different soil types by EA-IRMS system

International Nuclear Information System (INIS)

Qi Biao; Ding Lingling; Cui Jiehua; Wang Yanhong

2009-01-01

Element analyzer-isotope ratio mass spectrometers (EA-IRMS) is a rapid and precise method for measuring stable carbon isotope. Pure CO 2 reference gas was calibrated via international standard-Urea, and the δ 13 C us PDB value of pure CO 2 is (-29.523 ± 0.0181)%. Stability and linearity of the EA-IRMS system, precision of δ 13 C measurement for samples were tested through experimental comparison. Moreover, determination method of organic carbon stable isotope in soil was based on the system. The EA-IRMS system had well linearity when ion intensity ranged from 1.0 to 7.0V, and it excelled the total linearity when the ion intensity was from 1.5 to 5.0V, and the accurate result of δ 13 C for sample analysis could be obtained with precision of 0.015%. If carbon content in sample is more than 5μg, the requirement for analyzing accurate result of δ 13 C could be achieved. The organic carbon stable isotope was measured in 18 different types soil samples, the average natural abundance of 13 C was 1.082%, and the organic carbon stable isotope composition was significantly different among different type soils. (authors)

Stable boundary-layer regimes at dome C, Antarctica : observation and analysis

NARCIS (Netherlands)

Vignon, E.; van de Wiel, B.J.H.; van Hooijdonk, I.G.S.; Genthon, C.; van der Linden, S.J.A.; van Hooft, J.A.; Baas, P.; Maurel, W.; Traullé, O.; Casasanta, G.

2017-01-01

Investigation of meteorological measurements along a 45 m tower at Dome C on the high East Antarctic Plateau revealed two distinct stable boundary layer (SBL) regimes at this location. The first regime is characterized by strong winds and continuous turbulence. It results in full vertical coupling

Antibiotic therapy for stable non-CF bronchiectasis in adults

DEFF Research Database (Denmark)

Fjaellegaard, Katrine; Sin, Melda Dönmez; Browatzki, Andrea

2017-01-01

To provide an update on efficacy and safety of antibiotic treatments for stable non-cystic fibrosis (CF) bronchiectasis (BE). Systematic review based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines was done. Twenty-six studies (1.898 patients) fulfilled......, exacerbations and QoL, whereas studies on aztreonam revealed no significant clinical improvements in the outcomes of interest, including exacerbation rate. Adverse events, including bronchospasm, have been reported in association with tobramycin and aztreonam. Several antibiotic treatment regimens have been...... shown to improve QoL and exacerbation rate, whereas findings regarding sputum production, lung function and admissions have been conflicting. Evidence-based treatment algorithms for antibiotic treatment of stable non-CF BE will have to await large-scale, long-term controlled studies....

Stable isotopes reveal diet shift from pre-extinction to reintroduced Przewalski's horses.

Science.gov (United States)

Kaczensky, Petra; Burnik Šturm, Martina; Sablin, Mikhail V; Voigt, Christian C; Smith, Steve; Ganbaatar, Oyunsaikhan; Balint, Boglarka; Walzer, Chris; Spasskaya, Natalia N

2017-07-20

The Przewalski's horse (Equus ferus przewalskii), the only remaining wild horse within the equid family, is one of only a handful of species worldwide that went extinct in the wild, was saved by captive breeding, and has been successfully returned to the wild. However, concerns remain that after multiple generations in captivity the ecology of the Przewalski's horse and / or the ecological conditions in its former range have changed in a way compromising the species' long term survival. We analyzed stable isotope chronologies from tail hair of pre-extinction and reintroduced Przewalski's horses from the Dzungarian Gobi and detected a clear difference in the isotopic dietary composition. The direction of the dietary shift from being a mixed feeder in winter and a grazer in summer in the past, to a year-round grazer nowadays, is best explained by a release from human hunting pressure. A changed, positive societal attitude towards the species allows reintroduced Przewalski's horses to utilize the scarce, grass-dominated pastures of the Gobi alongside local people and their livestock whereas their historic conspecifics were forced into less productive habitats dominated by browse.

Quantifying inter-laboratory variability in stable isotope analysis of ancient skeletal remains.

Directory of Open Access Journals (Sweden)

William J Pestle

Full Text Available Over the past forty years, stable isotope analysis of bone (and tooth collagen and hydroxyapatite has become a mainstay of archaeological and paleoanthropological reconstructions of paleodiet and paleoenvironment. Despite this method's frequent use across anthropological subdisciplines (and beyond, the present work represents the first attempt at gauging the effects of inter-laboratory variability engendered by differences in a sample preparation, and b analysis (instrumentation, working standards, and data calibration. Replicate analyses of a 14C-dated ancient human bone by twenty-one archaeological and paleoecological stable isotope laboratories revealed significant inter-laboratory isotopic variation for both collagen and carbonate. For bone collagen, we found a sizeable range of 1.8‰ for δ13Ccol and 1.9‰ for δ15Ncol among laboratories, but an interpretatively insignificant average pairwise difference of 0.2‰ and 0.4‰ for δ13Ccol and δ15Ncol respectively. For bone hydroxyapatite the observed range increased to a troublingly large 3.5‰ for δ13Cap and 6.7‰ for δ18Oap, with average pairwise differences of 0.6‰ for δ13Cap and a disquieting 2.0‰ for δ18Oap. In order to assess the effects of preparation versus analysis on isotopic variability among laboratories, a subset of the samples prepared by the participating laboratories were analyzed a second time on the same instrument. Based on this duplicate analysis, it was determined that roughly half of the isotopic variability among laboratories could be attributed to differences in sample preparation, with the other half resulting from differences in analysis (instrumentation, working standards, and data calibration. These findings have serious implications for choices made in the preparation and extraction of target biomolecules, the comparison of results obtained from different laboratories, and the interpretation of small differences in bone collagen and hydroxyapatite

Quantifying inter-laboratory variability in stable isotope analysis of ancient skeletal remains.

Science.gov (United States)

Pestle, William J; Crowley, Brooke E; Weirauch, Matthew T

2014-01-01

Over the past forty years, stable isotope analysis of bone (and tooth) collagen and hydroxyapatite has become a mainstay of archaeological and paleoanthropological reconstructions of paleodiet and paleoenvironment. Despite this method's frequent use across anthropological subdisciplines (and beyond), the present work represents the first attempt at gauging the effects of inter-laboratory variability engendered by differences in a) sample preparation, and b) analysis (instrumentation, working standards, and data calibration). Replicate analyses of a 14C-dated ancient human bone by twenty-one archaeological and paleoecological stable isotope laboratories revealed significant inter-laboratory isotopic variation for both collagen and carbonate. For bone collagen, we found a sizeable range of 1.8‰ for δ13Ccol and 1.9‰ for δ15Ncol among laboratories, but an interpretatively insignificant average pairwise difference of 0.2‰ and 0.4‰ for δ13Ccol and δ15Ncol respectively. For bone hydroxyapatite the observed range increased to a troublingly large 3.5‰ for δ13Cap and 6.7‰ for δ18Oap, with average pairwise differences of 0.6‰ for δ13Cap and a disquieting 2.0‰ for δ18Oap. In order to assess the effects of preparation versus analysis on isotopic variability among laboratories, a subset of the samples prepared by the participating laboratories were analyzed a second time on the same instrument. Based on this duplicate analysis, it was determined that roughly half of the isotopic variability among laboratories could be attributed to differences in sample preparation, with the other half resulting from differences in analysis (instrumentation, working standards, and data calibration). These findings have serious implications for choices made in the preparation and extraction of target biomolecules, the comparison of results obtained from different laboratories, and the interpretation of small differences in bone collagen and hydroxyapatite isotope values

Transgenic zebrafish reveal tissue-specific differences in estrogen signaling in response to environmental water samples.

Science.gov (United States)

Gorelick, Daniel A; Iwanowicz, Luke R; Hung, Alice L; Blazer, Vicki S; Halpern, Marnie E

2014-04-01

Environmental endocrine disruptors (EEDs) are exogenous chemicals that mimic endogenous hormones such as estrogens. Previous studies using a zebrafish transgenic reporter demonstrated that the EEDs bisphenol A and genistein preferentially activate estrogen receptors (ERs) in the larval heart compared with the liver. However, it was not known whether the transgenic zebrafish reporter was sensitive enough to detect estrogens from environmental samples, whether environmental estrogens would exhibit tissue-specific effects similar to those of BPA and genistein, or why some compounds preferentially target receptors in the heart. We tested surface water samples using a transgenic zebrafish reporter with tandem estrogen response elements driving green fluorescent protein expression (5xERE:GFP). Reporter activation was colocalized with tissue-specific expression of ER genes by RNA in situ hybridization. We observed selective patterns of ER activation in transgenic fish exposed to river water samples from the Mid-Atlantic United States, with several samples preferentially activating receptors in embryonic and larval heart valves. We discovered that tissue specificity in ER activation was due to differences in the expression of ER subtypes. ERα was expressed in developing heart valves but not in the liver, whereas ERβ2 had the opposite profile. Accordingly, subtype-specific ER agonists activated the reporter in either the heart valves or the liver. The use of 5xERE:GFP transgenic zebrafish revealed an unexpected tissue-specific difference in the response to environmentally relevant estrogenic compounds. Exposure to estrogenic EEDs in utero was associated with adverse health effects, with the potentially unanticipated consequence of targeting developing heart valves.

On-line technique for preparingand measuring stable carbon isotopeof total dissolved inorganic carbonin water samples ( d13CTDIC

Directory of Open Access Journals (Sweden)

S. Inguaggiato

2005-06-01

Full Text Available A fast and completely automated procedure is proposed for the preparation and determination of d13C of total inorganic carbon dissolved in water ( d13CTDIC. This method is based on the acidification of water samples transforming the whole dissolved inorganic carbon species into CO2. Water samples are directly injected by syringe into 5.9 ml vials with screw caps which have a pierciable rubber septum. An Analytical Precision «Carbonate Prep System» was used both to flush pure helium into the vials and to automatically dispense a fixed amount of H3PO4. Full-equilibrium conditions between produced CO2 and water are reached at a temperature of 70°C (± 0.1°C in less than 24 h. Carbon isotope ratios (13C/ 12C were measured on an AP 2003 continuous flow mass spectrometer, connected on-line with the injection system. The precision and reproducibility of the proposed method was tested both on aqueous standard solutions prepared using Na2CO3 with d13C=-10.78 per mil versus PDB (1 s= 0.08, n = 11, and at five different concentrations (2, 3, 4, 5 and 20 mmol/l and on more than thirty natural samples. Mean d13CTDIC on standard solution samples is ?10.89 < per mil versus PDB (1 s= 0.18, n = 50, thus revealing both a good analytical precision and reproducibility. A comparison between average d13CTDIC values on a quadruplicate set of natural samples and those obtained following the chemical and physical stripping method highlights a good agreement between the two analytical methods.

Selection of reference genes for tissue/organ samples on day 3 fifth-instar larvae in silkworm, Bombyx mori.

Science.gov (United States)

Wang, Genhong; Chen, Yanfei; Zhang, Xiaoying; Bai, Bingchuan; Yan, Hao; Qin, Daoyuan; Xia, Qingyou

2018-06-01

The silkworm, Bombyx mori, is one of the world's most economically important insect. Surveying variations in gene expression among multiple tissue/organ samples will provide clues for gene function assignments and will be helpful for identifying genes related to economic traits or specific cellular processes. To ensure their accuracy, commonly used gene expression quantification methods require a set of stable reference genes for data normalization. In this study, 24 candidate reference genes were assessed in 10 tissue/organ samples of day 3 fifth-instar B. mori larvae using geNorm and NormFinder. The results revealed that, using the combination of the expression of BGIBMGA003186 and BGIBMGA008209 was the optimum choice for normalizing the expression data of the B. mori tissue/organ samples. The most stable gene, BGIBMGA003186, is recommended if just one reference gene is used. Moreover, the commonly used reference gene encoding cytoplasmic actin was the least appropriate reference gene of the samples investigated. The reliability of the selected reference genes was further confirmed by evaluating the expression profiles of two cathepsin genes. Our results may be useful for future studies involving the quantification of relative gene expression levels of different tissue/organ samples in B. mori. © 2018 Wiley Periodicals, Inc.

Distribution of radiocesium and stable elements within a pine tree

International Nuclear Information System (INIS)

Yoshida, S.; Watanabe, M.; Suzuki, A.

2011-01-01

Distributions of 137 Cs and stable elements in different parts of a pine tree collected in Chernobyl-contaminated area in Belarus were determined. Samples include annual tree rings of wood, branches and needles with different ages. The concentrations of 137 Cs and stable Cs in annual tree rings were the highest in cambium and decreased sharply towards inside. The youngest needles and branches contained higher 137 Cs and stable Cs than older ones. The concentration of 137 Cs being highest in growing parts suggests the highest radiation dose to the radiation-sensitive parts of tree. Distribution patterns of stable elements in pine tree differ among the elements. Distributions similar to those of Cs were observed for K and Rb, suggesting that alkaline metals tend to be translocated to young growing parts of pine tree. A similar distribution was also observed for phosphorus. Distributions of alkaline earth metals and several heavy metals were different from those of alkaline metals. (authors)

Laser-based measurements of 18O/16O stable isotope ratios (δ18O in wine samples

Directory of Open Access Journals (Sweden)

Gupta M

2013-09-01

Full Text Available Manish Gupta,1 J Brian Leen,1 Elena Simone Franklin Berman,1 Aldo Ciambotti2 1Los Gatos Research, Mountain View, CA, USA; 2Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per l'Enologia, Asti, Italy Abstract: Wine counterfeiting is an international, multi-billion dollar issue, with some estimates suggesting that up to 5% of wines sold at auctions or secondary markets are fraudulent. Isotope ratio mass spectrometer (IRMS measurements of the 18O/16O stable isotope ratio (δ18O of water-in-wine have been used for wine authentication; however, these analyses are time-consuming and costly. In this preliminary study, off-axis integrated cavity output spectroscopy (OA-ICOS is used to quantify δ18O in wines. This laser-based method has been extensively used to study water isotopes for hydrological and medical applications. Recently, the development of a spectral contaminant identifier (SCI has extended the application of these OA-ICOS analyzers to contaminated water samples (eg, plant, soil, and leaf waters. Here, we utilize OA-ICOS with the SCI to characterize wine samples (9%–15% ethanol, and show that the laser-based instrument provides a δ18O measurement precision of ±0.07‰ (1σ and agrees with IRMS to within ±0.63‰ (1σ. Moreover, by training the SCI on isotopically-characterized wines, the agreement with IRMS improves to within ±0.30‰ (1σ. The utility of the instrument is demonstrated by measuring watered and mixed wines. The method presented here can be readily extended to address other food authentication applications. Keywords: wine isotopes, wine fraud, counterfeit wines, OA-ICOS

Radappertization of ready-to-eat shelf-stable, traditional Indian bread - Methi Paratha

International Nuclear Information System (INIS)

Bhoir, Shraddha A.; Muppalla, Shobita R.; Kanatt, Sweetie R.; Chawla, S.P.; Sharma, Arun

2015-01-01

Shelf-stable ready-to-eat (RTE) Methi Paratha (flavored Indian unleavened flat bread) was developed using combination of hurdles including radiation processing. The Methi Paratha was prepared using dough containing wheat flour, dried fenugreek leaves and spices. The samples were vacuum packed in multi-layered pouches and irradiated at 25 kGy in frozen conditions. Samples were evaluated for microbiological counts, lipid peroxidation and sensory attributes during storage under ambient conditions. Samples were found to be devoid of any viable microorganism throughout the storage period of 180 days. The thiobarbituric acid reactive substances (TBARS) value which indicates lipid peroxidation of samples did not show any significant increase with time. The Methi Paratha was found to be acceptable by the evaluating panelists. - Highlights: • Shelf-stable ready-to-eat (RTE) Methi Paratha (flavored Indian unleavened flat bread) was developed. • A combination of hurdles irradiation, vacuum-packaging and natural antioxidants was used. • Methi Paratha was microbiologically safe and sensorialy acceptable for 180 days

Generalized sampling in Julia

DEFF Research Database (Denmark)

Jacobsen, Christian Robert Dahl; Nielsen, Morten; Rasmussen, Morten Grud

2017-01-01

Generalized sampling is a numerically stable framework for obtaining reconstructions of signals in different bases and frames from their samples. For example, one can use wavelet bases for reconstruction given frequency measurements. In this paper, we will introduce a carefully documented toolbox...... for performing generalized sampling in Julia. Julia is a new language for technical computing with focus on performance, which is ideally suited to handle the large size problems often encountered in generalized sampling. The toolbox provides specialized solutions for the setup of Fourier bases and wavelets....... The performance of the toolbox is compared to existing implementations of generalized sampling in MATLAB....

Stable isotope ratios in hair and teeth reflect biologic rhythms.

Directory of Open Access Journals (Sweden)

Otto Appenzeller

Full Text Available Biologic rhythms give insight into normal physiology and disease. They can be used as biomarkers for neuronal degenerations. We present a diverse data set to show that hair and teeth contain an extended record of biologic rhythms, and that analysis of these tissues could yield signals of neurodegenerations. We examined hair from mummified humans from South America, extinct mammals and modern animals and people, both healthy and diseased, and teeth of hominins. We also monitored heart-rate variability, a measure of a biologic rhythm, in some living subjects and analyzed it using power spectra. The samples were examined to determine variations in stable isotope ratios along the length of the hair and across growth-lines of the enamel in teeth. We found recurring circa-annual periods of slow and fast rhythms in hydrogen isotope ratios in hair and carbon and oxygen isotope ratios in teeth. The power spectra contained slow and fast frequency power, matching, in terms of normalized frequency, the spectra of heart rate variability found in our living subjects. Analysis of the power spectra of hydrogen isotope ratios in hair from a patient with neurodegeneration revealed the same spectral features seen in the patient's heart-rate variability. Our study shows that spectral analysis of stable isotope ratios in readily available tissues such as hair could become a powerful diagnostic tool when effective treatments and neuroprotective drugs for neurodegenerative diseases become available. It also suggests that similar analyses of archaeological specimens could give insight into the physiology of ancient people and animals.

Estimation of evapotranspiration rate in irrigated lands using stable isotopes

Science.gov (United States)

Umirzakov, Gulomjon; Windhorst, David; Forkutsa, Irina; Brauer, Lutz; Frede, Hans-Georg

2013-04-01

Agriculture in the Aral Sea basin is the main consumer of water resources and due to the current agricultural management practices inefficient water usage causes huge losses of freshwater resources. There is huge potential to save water resources in order to reach a more efficient water use in irrigated areas. Therefore, research is required to reveal the mechanisms of hydrological fluxes in irrigated areas. This paper focuses on estimation of evapotranspiration which is one of the crucial components in the water balance of irrigated lands. Our main objective is to estimate the rate of evapotranspiration on irrigated lands and partitioning of evaporation into transpiration using stable isotopes measurements. Experiments has done in 2 different soil types (sandy and sandy loam) irrigated areas in Ferghana Valley (Uzbekistan). Soil samples were collected during the vegetation period. The soil water from these samples was extracted via a cryogenic extraction method and analyzed for the isotopic ratio of the water isotopes (2H and 18O) based on a laser spectroscopy method (DLT 100, Los Gatos USA). Evapotranspiration rates were estimated with Isotope Mass Balance method. The results of evapotranspiration obtained using isotope mass balance method is compared with the results of Catchment Modeling Framework -1D model results which has done in the same area and the same time.

Suitable activated stable nuclide tracer technique and its applications in biology and medicine

International Nuclear Information System (INIS)

Zhang Weicheng

1989-01-01

Stable isotopes as tracers in biology and medicine have been more extensively used. Mass spectrometry has been a classic technique in the analysis of stable isotopes because it is very sensitive and precise. Activation analysis has recently been introduced as an analytical tool. Its fast speed and simplicity is a great advantage for handling large batches of samples in isotopic tracer experiments. The combination of enriched stable isotope tracer studies and activation analysis techniques has become an ideal and reliable technique, especially in the fields of biology and medicine. This paper presents a survey of the fundamental principle, the character and the applications in biology and medicine for the suitable activated stable isotope tracer techniques

Dynamic equilibrium of radiocesium with stable cesium within the soil-mushroom system in Turkish pine forest

International Nuclear Information System (INIS)

Karadeniz, Ozlem; Yaprak, Guenseli

2007-01-01

Mushrooms and soils collected from pine forests in Izmir, Turkey were measured for radiocesium and stable Cs in 2002. The ranges of 137 Cs and stable Cs concentrations in mushrooms were 9.84 ± 1.67 to 401 ± 3.85 Bq kg -1 dry weight and 0.040 ± 0.004 to 11.3 ± 1.09 mg kg -1 dry weight, respectively. The concentrations of 137 Cs and stable Cs in soils were 0.29 ± 0.18 to 161 ± 1.12 Bq kg -1 dry weight and 0.14 ± 0.004 to 1.44 ± 0.045 mg kg -1 dry weight, respectively. Even though different species were included, the concentration ratios of 137 Cs to stable Cs were fairly constant for samples collected at the same forest site, and were in the same order of magnitude as the 137 Cs to stable Cs ratios for the organic soil layers. The soil-to-mushroom transfer factors of 137 Cs and stable Cs were in the range of 0.19-3.15 and 0.17-12.3, respectively. The transfer factors of 137 Cs were significantly correlated to those of stable Cs. - The 137 Cs/ 133 Cs ratios observed in mushroom samples and in organic layers shows that 137 Cs is well mixed with stable Cs within the biological cycle in the studied pine forest

Beyond Contagion: Reality Mining Reveals Complex Patterns of Social Influence.

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Aamena Alshamsi

Full Text Available Contagion, a concept from epidemiology, has long been used to characterize social influence on people's behavior and affective (emotional states. While it has revealed many useful insights, it is not clear whether the contagion metaphor is sufficient to fully characterize the complex dynamics of psychological states in a social context. Using wearable sensors that capture daily face-to-face interaction, combined with three daily experience sampling surveys, we collected the most comprehensive data set of personality and emotion dynamics of an entire community of work. From this high-resolution data about actual (rather than self-reported face-to-face interaction, a complex picture emerges where contagion (that can be seen as adaptation of behavioral responses to the behavior of other people cannot fully capture the dynamics of transitory states. We found that social influence has two opposing effects on states: adaptation effects that go beyond mere contagion, and complementarity effects whereby individuals' behaviors tend to complement the behaviors of others. Surprisingly, these effects can exhibit completely different directions depending on the stable personality or emotional dispositions (stable traits of target individuals. Our findings provide a foundation for richer models of social dynamics, and have implications on organizational engineering and workplace well-being.

Beyond Contagion: Reality Mining Reveals Complex Patterns of Social Influence.

Science.gov (United States)

Alshamsi, Aamena; Pianesi, Fabio; Lepri, Bruno; Pentland, Alex; Rahwan, Iyad

2015-01-01

Contagion, a concept from epidemiology, has long been used to characterize social influence on people's behavior and affective (emotional) states. While it has revealed many useful insights, it is not clear whether the contagion metaphor is sufficient to fully characterize the complex dynamics of psychological states in a social context. Using wearable sensors that capture daily face-to-face interaction, combined with three daily experience sampling surveys, we collected the most comprehensive data set of personality and emotion dynamics of an entire community of work. From this high-resolution data about actual (rather than self-reported) face-to-face interaction, a complex picture emerges where contagion (that can be seen as adaptation of behavioral responses to the behavior of other people) cannot fully capture the dynamics of transitory states. We found that social influence has two opposing effects on states: adaptation effects that go beyond mere contagion, and complementarity effects whereby individuals' behaviors tend to complement the behaviors of others. Surprisingly, these effects can exhibit completely different directions depending on the stable personality or emotional dispositions (stable traits) of target individuals. Our findings provide a foundation for richer models of social dynamics, and have implications on organizational engineering and workplace well-being.

The calcineurin activity profiles of cyclosporin and tacrolimus are different in stable renal transplant patients

DEFF Research Database (Denmark)

Koefoed-Nielsen, Pernille Bundgaard; Karamperis, Nikolaos; Jørgensen, Kaj Anker

2006-01-01

in determining optimal doses. Forty stable renal transplant patients were investigated three times in a 6-month period. Blood samples were drawn at 0, 1, 2, 3 and 4 h after oral intake of tacrolimus (FK) or cyclosporin at days 1 and 180. At day 90, one blood sample at trough level (FK) or C2 level (cyclosporin A...... significantly different effects on calcineurin activity in renal transplant patients with stable, well-functioning grafts and that tacrolimus-treated patients can maintain good, stable graft function with minimal CaN inhibition.......Cyclosporin and tacrolimus remain the cornerstone immunosuppressive drugs in organ transplantation. Dosing and monitoring these drugs is based on pharmacokinetic protocols, but measuring a pharmacodynamic parameter, calcineurin phosphatase (CaN) activity, could be a valuable supplement...

Sampled-Data Consensus of Linear Multi-agent Systems With Packet Losses.

Science.gov (United States)

Zhang, Wenbing; Tang, Yang; Huang, Tingwen; Kurths, Jurgen

In this paper, the consensus problem is studied for a class of multi-agent systems with sampled data and packet losses, where random and deterministic packet losses are considered, respectively. For random packet losses, a Bernoulli-distributed white sequence is used to describe packet dropouts among agents in a stochastic way. For deterministic packet losses, a switched system with stable and unstable subsystems is employed to model packet dropouts in a deterministic way. The purpose of this paper is to derive consensus criteria, such that linear multi-agent systems with sampled-data and packet losses can reach consensus. By means of the Lyapunov function approach and the decomposition method, the design problem of a distributed controller is solved in terms of convex optimization. The interplay among the allowable bound of the sampling interval, the probability of random packet losses, and the rate of deterministic packet losses are explicitly derived to characterize consensus conditions. The obtained criteria are closely related to the maximum eigenvalue of the Laplacian matrix versus the second minimum eigenvalue of the Laplacian matrix, which reveals the intrinsic effect of communication topologies on consensus performance. Finally, simulations are given to show the effectiveness of the proposed results.In this paper, the consensus problem is studied for a class of multi-agent systems with sampled data and packet losses, where random and deterministic packet losses are considered, respectively. For random packet losses, a Bernoulli-distributed white sequence is used to describe packet dropouts among agents in a stochastic way. For deterministic packet losses, a switched system with stable and unstable subsystems is employed to model packet dropouts in a deterministic way. The purpose of this paper is to derive consensus criteria, such that linear multi-agent systems with sampled-data and packet losses can reach consensus. By means of the Lyapunov function

Metal-organic framework based in-syringe solid-phase extraction for the on-site sampling of polycyclic aromatic hydrocarbons from environmental water samples.

Science.gov (United States)

Zhang, Xiaoqiong; Wang, Peiyi; Han, Qiang; Li, Hengzhen; Wang, Tong; Ding, Mingyu

2018-04-01

In-syringe solid-phase extraction is a promising sample pretreatment method for the on-site sampling of water samples because of its outstanding advantages of portability, simple operation, short extraction time, and low cost. In this work, a novel in-syringe solid-phase extraction device using metal-organic frameworks as the adsorbent was fabricated for the on-site sampling of polycyclic aromatic hydrocarbons from environmental waters. Trace polycyclic aromatic hydrocarbons were effectively extracted through the self-made device followed by gas chromatography with mass spectrometry analysis. Owing to the excellent adsorption performance of metal-organic frameworks, the analytes could be completely adsorbed during one adsorption cycle, thus effectively shortening the extraction time. Moreover, the adsorbed analytes could remain stable on the device for at least 7 days, revealing the potential of the self-made device for on-site sampling of degradable compounds in remote regions. The limit of detection ranged from 0.20 to 1.9 ng/L under the optimum conditions. Satisfactory recoveries varying from 84.4 to 104.5% and relative standard deviations below 9.7% were obtained in real samples analysis. The results of this study promote the application of metal-organic frameworks in sample preparation and demonstrate the great potential of in-syringe solid-phase extraction for the on-site sampling of trace contaminants in environmental waters. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Life in Ice: Microbial Growth Dynamics and Greenhouse Gas Production During Winter in a Thermokarst Bog Revealed by Stable Isotope Probing Targeted Metagenomics

Science.gov (United States)

Blazewicz, S.; White, R. A., III; Tas, N.; Euskirchen, E. S.; Mcfarland, J. W.; Jansson, J.; Waldrop, M. P.

2016-12-01

Permafrost contains a reservoir of frozen C estimated to be twice the size of the current atmospheric C pool. In response to changing climate, permafrost is rapidly warming which could result in widespread seasonal thawing. When permafrost thaws, soils that are rich in ice and C often transform into thermokarst wetlands with anaerobic conditions and significant production of atmospheric CH4. While most C flux research in recently thawed permafrost concentrates on the few summer months when seasonal thaw has occurred, there is mounting evidence that sizeable portions of annual CO2 and CH4 efflux occurs over winter or during a rapid burst of emissions associated with seasonal thaw. A potential mechanism for such efflux patterns is microbial activity in frozen soils over winter where gasses produced are partially trapped within ice until spring thaw. In order to better understand microbial transformation of soil C to greenhouse gas over winter, we applied stable isotope probing (SIP) targeted metagenomics combined with process measurements and field flux data to reveal activities of microbial communities in `frozen' soil from an Alaskan thermokarst bog. Field studies revealed build-up of CO2 and CH4 in frozen soils suggesting that microbial activity persisted throughout the winter in soils poised just below the freezing point. Laboratory incubations designed to simulate in-situ winter conditions (-1.5 °C and anaerobic) revealed continuous CH4 and CO2 production. Strikingly, the quantity of CH4 produced in 6 months in frozen soil was equivalent to approximately 80% of CH4 emitted during the 3 month summer `active' season. Heavy water SIP targeted iTag sequencing revealed growing bacteria and archaea in the frozen anaerobic soil. Growth was primarily observed in two bacterial phyla, Firmicutes and Bacteroidetes, suggesting that fermentation was likely the major C mineralization pathway. SIP targeted metagenomics facilitated characterization of the primary metabolic

Assessing the Utility of Hydrogen, Carbon and Nitrogen Stable Isotopes in Estimating Consumer Allochthony in Two Shallow Eutrophic Lakes.

Directory of Open Access Journals (Sweden)

Jari Syväranta

Full Text Available Hydrogen stable isotopes (δ2H have recently been used to complement δ13C and δ15N in food web studies due to their potentially greater power to separate sources of organic matter in aquatic food webs. However, uncertainties remain regarding the use of δ2H, since little is known about the potential variation in the amount of exchangeable hydrogen (Hex among common sample materials or the patterns of δ2H when entire food webs are considered. We assessed differences in Hex among the typical sample materials in freshwater studies and used δ2H, δ13C and δ15N to compare their effectiveness in tracing allochthonous matter in food webs of two small temperate lakes. Our results showed higher average amounts of Hex in animal tissues (27% in fish and macroinvertebrates, 19% in zooplankton compared to most plant material (15% in terrestrial plants and 8% in seston/periphyton, with the exception of aquatic vascular plants (23%, referred to as macrophytes. The amount of Hex correlated strongly with sample lipid content (inferred from C:N ratios in fish and zooplankton samples. Overall, the three isotopes provided good separation of sources (seston, periphyton, macrophytes and allochthonous organic matter, particularly the δ2H followed by δ13C. Aquatic macrophytes revealed unexpectedly high δ2H values, having more elevated δ2H values than terrestrial organic matter with direct implications for estimating consumer allochthony. Organic matter from macrophytes significantly contributed to the food webs in both lakes highlighting the need to include macrophytes as a potential source when using stable isotopes to estimate trophic structures and contributions from allochthonous sources.

The neodymium stable isotope composition of the silicate Earth and chondrites

Science.gov (United States)

McCoy-West, Alex J.; Millet, Marc-Alban; Burton, Kevin W.

2017-12-01

The non-chondritic neodymium (Nd) 142Nd/144Nd ratio of the silicate Earth potentially provides a key constraint on the accretion and early evolution of the Earth. Yet, it is debated whether this offset is due to the Earth being formed from material enriched in s-process Nd isotopes or results from an early differentiation process such as the segregation of a late sulfide matte during core formation, collisional erosion or a some combination of these processes. Neodymium stable isotopes are potentially sensitive to early sulfide segregation into Earth's core, a process that cannot be resolved using their radiogenic counterparts. This study presents the first comprehensive Nd stable isotope data for chondritic meteorites and terrestrial rocks. Stable Nd measurements were made using a double spike technique coupled with thermal ionisation mass spectrometry. All three of the major classes of chondritic meteorites, carbonaceous, enstatite and ordinary chondrites have broadly similar isotopic compositions allowing calculation of a chondritic mean of δ146/144Nd = -0.025 ± 0.025‰ (±2 s.d.; n = 39). Enstatite chondrites yield the most uniform stable isotope composition (Δ146/144Nd = 26 ppm), with considerably more variability observed within ordinary (Δ146/144Nd = 72 ppm) and carbonaceous meteorites (Δ146/144Nd = 143 ppm). Terrestrial weathering, nucleosynthetic variations and parent body thermal metamorphism appear to have little measurable effect on δ146/144Nd in chondrites. The small variations observed between ordinary chondrite groups most likely reflect inherited compositional differences between parent bodies, with the larger variations observed in carbonaceous chondrites being linked to varying modal proportions of calcium-aluminium rich inclusions. The terrestrial samples analysed here include rocks ranging from basaltic to rhyolitic in composition, MORB glasses and residual mantle lithologies. All of these terrestrial rocks possess a broadly similar Nd

Method for determination of stable carbon isotope ratio of methylnitrophenols in atmospheric particulate matter

Directory of Open Access Journals (Sweden)

S. Moukhtar

2011-11-01

Full Text Available A technique for the measurement of the stable isotope ratio of methylnitrophenols in atmospheric particulate matter is presented. Atmospheric samples from rural and suburban areas were collected for evaluation of the procedure. Particulate matter was collected on quartz fibre filters using dichotomous high volume air samplers. Methylnitrophenols were extracted from the filters using acetonitrile. The sample was then purified using a combination of high-performance liquid chromatography and solid phase extraction. The final solution was then divided into two aliquots. To one aliquot, a derivatising agent, Bis(trimethylsilyltrifluoroacetamide, was added for Gas Chromatography-Mass Spectrometry analysis. The second half of the sample was stored in a refrigerator. For samples with concentrations exceeding 1 ng μl⁻¹, the second half of the sample was used for measurement of stable carbon isotope ratios by Gas Chromatography-Isotope Ratio Mass Spectrometry.

The procedure described in this paper provides a method for the analysis of methylnitrophenols in atmospheric particulate matter at concentrations as low as 0.3 pg m⁻³ and for stable isotope ratios with an accuracy of better than ±0.5‰ for concentrations exceeding 100 pg m⁻³.

In all atmospheric particulate matter samples analysed, 2-methyl-4-nitrophenol was found to be the most abundant methylnitrophenol, with concentrations ranging from the low pg m⁻³ range in rural areas to more than 200 pg m⁻³ in some samples from a suburban location.

Concentrations of radionuclides and selected stable elements in fruits and vegetables

International Nuclear Information System (INIS)

Oakes, T.W.; Shank, K.E.

1977-01-01

Twenty-two types of fruits and vegetables collected from two commercial supermarkets have been analyzed for their radionuclidic and stable-element composition. A specific gamma-emitting isotope analysis was performed on each sample for 40 K, 60 Co, 95 Zr-Nb, 106 Ru, 137 Cs, 226 Ra, and 232 Th. The concentration of the stable elements in each sample were determined using multi-element neutron-activation analysis (Al, Ag, Au, As, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Eu, Fe, Hf, I, K, La, Mn, Mo, Mg, Na, Rb, Sb, Sc, Se, Sr, Ta, Te, Th, Ti, Zn, Zr) and atomic absorption (Cd, Ni, Pb). Information on the composition of a typical diet is used to estimate the radiological dose to man subsequent to ingestion of these fruits and vegetables. The stable-elemental compositions of the foodstuffs analyzed were compared with estimated values assuming foliar deposition and long-term buildup of effluents from a large modern coal-fired steam plant. It is tentatively concluded that for the general case of a precipitator-equipped, coal-fired steam plant, no toxic levels of trace elements in foodstuffs are expected as a result of the plant operation

Determination of the alkylpyrazine composition of coffee using stable isotope dilution-gas chromatography-mass spectrometry (SIDA-GC-MS).

Science.gov (United States)

Pickard, Stephanie; Becker, Irina; Merz, Karl-Heinz; Richling, Elke

2013-07-03

A stable isotope dilution analysis based on gas chromatography-mass spectrometry analysis (SIDA-GC-MS) was developed for the quantitative analysis of 12 alkylpyrazines found in commercially available coffee samples. These compounds contribute to coffee flavor. The accuracy of this method was tested by analyzing model mixtures of alkylpyrazines. Comparisons of alkylpyrazine-concentrations suggested that water as extraction solvent was superior to dichloromethane. The distribution patterns of alkylpyrazines in different roasted coffees were quite similar. The most abundant alkylpyrazine in each coffee sample was 2-methylpyrazine, followed by 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine, and 2,3,5-trimethylpyrazine, respectively. Among the alkylpyrazines tested, 2,3-dimethylpyrazine, 2-ethyl-3-methylpyrazine, 2-ethyl-3,6-dimethylpyrazine, and 2-ethyl-3,5-dimethylpyrazine revealed the lowest concentrations in roasted coffee. By the use of isotope dilution analysis, the total concentrations of alkylpyrazines in commercially available ground coffee ranged between 82.1 and 211.6 mg/kg, respectively. Decaffeinated coffee samples were found to contain lower amounts of alkylpyrazines than regular coffee samples by a factor of 0.3-0.7, which might be a result of the decaffeination procedure.

Trophic Niche Differentiation in Rodents and Marsupials Revealed by Stable Isotopes.

Directory of Open Access Journals (Sweden)

Mauro Galetti

Full Text Available Tropical rainforests support the greatest diversity of small mammals in the world, yet we have little understanding about the mechanisms that promote the coexistence of species. Diet partitioning can favor coexistence by lessening competition, and interspecific differences in body size and habitat use are usually proposed to be associated with trophic divergence. However, the use of classic dietary methods (e.g. stomach contents is challenging in small mammals, particularly in community-level studies, thus we used stable isotopes (δ13C and δ15N to infer about trophic niche. We investigated i how trophic niche is partitioned among rodent and marsupial species in three Atlantic forest sites and ii if interspecific body size and locomotor habit inequalities can constitute mechanisms underlying the isotopic niche partitioning. We found that rodents occupied a broad isotopic niche space with species distributed in different trophic levels and relying on diverse basal carbon sources (C3 and C4 plants. Surprisingly, on the other hand, marsupials showed a narrow isotopic niche, both in δ13C and δ15N dimensions, which is partially overlapped with rodents, contradicting their description as omnivores and generalists proposed classic dietary studies. Although body mass differences did not explained the divergence in isotopic values among species, groups of species with different locomotor habit presented clear differences in the position of the isotopic niche space, indicating that the use of different forest strata can favor trophic niche partitioning in small mammals communities. We suggest that anthropogenic impacts, such as habitat modification (logging, harvesting, can simplify the vertical structure of ecosystems and collapse the diversity of basal resources, which might affect negatively small mammals communities in Atlantic forests.

Golan Heights Groundwater Systems: Separation By REE+Y And Stable Isotopes

Science.gov (United States)

Siebert, C.; Geyer, S.; Knoeller, K.; Roediger, T.; Weise, S.; Dulski, P.; Moeller, P.; Guttman, J.

2008-12-01

In a semi-arid to arid country like Israel, all freshwater resources are under (over-) utilization. Particularly, the Golan Heights rank as one of the most important extraction areas of groundwater of good quality and quantity. Additionally the mountain range feed to a high degree the most important freshwater reservoir of Israel, the Sea of Galilee. Hence, knowing the sources and characters of the Golan Heights groundwater systems is an instantaneous demand regarding sustainable management and protection. Within the "German-Israeli-Jordanian-Palestinian Joint Research Program for the Sustainable Utilisation of Aquifer Systems", hundreds of water samples were taken from all over the Jordan-Dead Sea rift-system to understand groundwater flow-systems and salinisation. For that purpose, each sample was analysed for major and minor ions, rare earth elements including yttrium (REY) and stable isotopes of water (d18O, d2H). The REY distribution in groundwater is established during infiltration by the first water-rock interaction and consequently reflects the leachable components of sediments and rocks of the recharge area. In well- developed flow-systems, REY are adsorbed onto pore surfaces are in equilibrium with the percolating groundwater, even if the lithology changes (e.g. inter-aquifer flow). Thus, groundwater sampled from wells and springs still show the REY distribution pattern established in the recharge area. Since high temperatures do not occur in Golan Heights, d2H and d18O are less controlled by water-rock interaction than by climatic and geomorphological factors at the time of replenishment. Applying the REY signature as a grouping criterion of groundwaters, d18O vs. d2H plots yield a new dimension in interpreting isotope data. The combined use of hydrochemical and isotopic methods enabled us to contain the areas of replenishment and the flow-paths of all investigated groundwater in the Golan Heights. Despite location, salinity or temperature of spring or

One-dimensional stable distributions

CERN Document Server

Zolotarev, V M

1986-01-01

This is the first book specifically devoted to a systematic exposition of the essential facts known about the properties of stable distributions. In addition to its main focus on the analytic properties of stable laws, the book also includes examples of the occurrence of stable distributions in applied problems and a chapter on the problem of statistical estimation of the parameters determining stable laws. A valuable feature of the book is the author's use of several formally different ways of expressing characteristic functions corresponding to these laws.

Targeted Genome Sequencing Reveals Varicella-Zoster Virus Open Reading Frame 12 Deletion.

Science.gov (United States)

Cohrs, Randall J; Lee, Katherine S; Beach, Addilynn; Sanford, Bridget; Baird, Nicholas L; Como, Christina; Graybill, Chiharu; Jones, Dallas; Tekeste, Eden; Ballard, Mitchell; Chen, Xiaomi; Yalacki, David; Frietze, Seth; Jones, Kenneth; Lenac Rovis, Tihana; Jonjić, Stipan; Haas, Jürgen; Gilden, Don

2017-10-15

The neurotropic herpesvirus varicella-zoster virus (VZV) establishes a lifelong latent infection in humans following primary infection. The low abundance of VZV nucleic acids in human neurons has hindered an understanding of the mechanisms that regulate viral gene transcription during latency. To overcome this critical barrier, we optimized a targeted capture protocol to enrich VZV DNA and cDNA prior to whole-genome/transcriptome sequence analysis. Since the VZV genome is remarkably stable, it was surprising to detect that VZV32, a VZV laboratory strain with no discernible growth defect in tissue culture, contained a 2,158-bp deletion in open reading frame (ORF) 12. Consequently, ORF 12 and 13 protein expression was abolished and Akt phosphorylation was inhibited. The discovery of the ORF 12 deletion, revealed through targeted genome sequencing analysis, points to the need to authenticate the VZV genome when the virus is propagated in tissue culture. IMPORTANCE Viruses isolated from clinical samples often undergo genetic modifications when cultured in the laboratory. Historically, VZV is among the most genetically stable herpesviruses, a notion supported by more than 60 complete genome sequences from multiple isolates and following multiple in vitro passages. However, application of enrichment protocols to targeted genome sequencing revealed the unexpected deletion of a significant portion of VZV ORF 12 following propagation in cultured human fibroblast cells. While the enrichment protocol did not introduce bias in either the virus genome or transcriptome, the findings indicate the need for authentication of VZV by sequencing when the virus is propagated in tissue culture. Copyright © 2017 American Society for Microbiology.

Ca2Cr0.5Ga1.5O5—An extremely redox-stable brownmillerite phase

International Nuclear Information System (INIS)

Luo, Kun; Amano Patino, Midori; Hayward, Michael A.

2015-01-01

Investigation of the Ca 2 Cr x Ga 2−x O 5 compositional series reveals a maximum chromium solubility of 25%. The most chromium rich composition, Ca 2 Cr 0.5 Ga 1.5 O 5 , adopts a brownmillerite-type anion deficient perovskite structure described in space group Pnma (a=5.368 Å, b=14.547 Å, c=5.593 Å). Neutron powder diffraction data reveals rigorous B-site cation order, with all of the tetrahedral coordination sites occupied exclusively by gallium and the octahedral coordination sites occupied by gallium or chromium. Annealing studies reveals Ca 2 Cr 0.5 Ga 1.5 O 5 is stable in both oxidizing (100% O 2 ) and reducing (5% H 2 in N 2 ) conditions up to 800 °C, suggesting it could find application as a stable host lattice for fuel cell electrodes or electrolytes with suitable doping to enhance catalytic behaviour and/or anionic conductivity. - Graphical abstract: Ca 2 Cr 0.5 Ga 1.5 O 5 , adopts a brownmillerite-type anion deficient perovskite structure yet it is stable in both oxidizing (100% O 2 ) and reducing (5% H 2 in N 2 ) conditions up to 800 °C. - Highlights: • Anion deficient oxide stable to both oxidation and reduction up to 800 °C. • Cation-ordered brownmillerite structure determined by powder neutron diffraction. • Low solubility of Cr 3+ in framework due to spherical d 3 electron configuration

Bi-stable optical actuator

Science.gov (United States)

Holdener, Fred R.; Boyd, Robert D.

2000-01-01

The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

Stable carbon and nitrogen isotope ratios of sodium and potassium cyanide as a forensic signature.

Science.gov (United States)

Kreuzer, Helen W; Horita, Juske; Moran, James J; Tomkins, Bruce A; Janszen, Derek B; Carman, April

2012-01-01

Sodium and potassium cyanide are highly toxic, produced in large amounts by the chemical industry, and linked to numerous high-profile crimes. The U.S. Centers for Disease Control and Prevention has identified cyanide as one of the most probable agents to be used in a chemical terrorism event. We investigated whether stable C and N isotopic content of sodium and potassium cyanide could serve as a forensic signature for sample matching, using a collection of 65 cyanide samples. Upon analysis, a few of the cyanide samples displayed nonhomogeneous isotopic content associated with degradation to a carbonate salt and loss of hydrogen cyanide. Most samples had highly reproducible isotope content. Of the 65 cyanide samples, >95% could be properly matched based on C and N isotope ratios, with a false match rate <3%. These results suggest that stable C and N isotope ratios are a useful forensic signature for matching cyanide samples. © 2011 American Academy of Forensic Sciences.

High-beta characteristics of first and second-stable spherical tokamaks in reconnection heating experiments of TS-3

International Nuclear Information System (INIS)

Ono, Y.

2002-01-01

Novel formations of ultra-high-beta Spherical Tokamak (ST) have been developed in the TS-3 device using high power heating of merging/ reconnection. In Type-A merging, two STs were merged together to build up the plasma beta. In Type-B merging, an oblate FRC was initially formed by merging of two spheromaks with opposing toroidal field B t and was transformed into an ultra-high-beta ST by applying external B t . Ballooning stability analyses confirmed formations of the first-stable STs by Type- A merging and the second-stable STs by Type-B merging and also the unstable STs by both mergings, revealing the ballooning stability window consistent with measured high-n instabilities. We made (1) those model analyses of the produced STs for the first time using the BALLOO stability code, revealing that hollowness/ broadness of current/pressure profiles widen significantly the window to the second-stable regime. This paper also addresses (2) normalized betas of the second-stable STs as large as 6-17 for comparison with the Troyon scaling and (3) a promising scaling of the reconnection heating energy. (author)

Remarks on stable and quasi-stable k-strings at large N

International Nuclear Information System (INIS)

Armoni, A.; Shifman, M.

2003-01-01

We discuss k-strings in the large-N Yang-Mills theory and its supersymmetric extension. Whereas the tension of the bona fide (stable) QCD string is expected to depend only on the N-ality of the representation, tensions that depend on specific representation R are often reported in the lattice literature. In particular, adjoint strings are discussed and found in certain simulations. We clarify this issue by systematically exploiting the notion of the quasi-stable strings which becomes well-defined at large N. The quasi-stable strings with representation-dependent tensions decay, but the decay rate (per unit length per unit time) is suppressed as Λ 2 F(N) where F(N) falls off as a function of N. It can be determined on the case-by-case basis. The quasi-stable strings eventually decay into stable strings whose tension indeed depends only on the N-ality. We also briefly review large-N arguments showing why the Casimir formula for the string tension cannot be correct, and present additional arguments in favor of the sine formula. Finally, we comment on the relevance of our estimates to Euclidean lattice measurements

Evolutionary Stable Strategy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General Article Volume 21 Issue 9 September 2016 pp 803- ... Keywords. Evolutionary game theory, evolutionary stable state, conflict, cooperation, biological games.

An Ocean Sediment Core-Top Calibration of Foraminiferal (Cibicides) Stable Carbon Isotope Ratios

Science.gov (United States)

Schmittner, A.; Mix, A. C.; Lisiecki, L. E.; Peterson, C.; Mackensen, A.; Cartapanis, O. A.

2015-12-01

Stable carbon isotope ratios (δ13C) measured on calcium carbonate shells of benthic foraminifera (cibicides) from late Holocene sediments (δ13CCib) are compiled and compared with newly updated datasets of contemporary water-column δ13C observations of dissolved inorganic carbon (δ13CDIC) as the initial core-top calibration of the international Ocean Circulation and CarbonCycling (OC3) project. Using selection criteria based on the spatial distance between samples we find high correlation between δ13CCib and natural (pre-industrial) δ13CDIC, confirming earlier work. However, our analysis reveals systematic differences such as higher (lower) δ13CCib values in the Atlantic (Indian and Pacific) oceans. Regression analyses are impacted by anthropogenic carbon and suggest significant carbonate ion, temperature, and pressure effects, consistent with lab experiments with planktonic foraminifera and theory. The estimated standard error of core-top sediment data is generally σ ~= 0.25 ‰, whereas modern foram data from the South Atlantic indicate larger errors (σ ~= 0.4 ‰).

UV-laser-based microscopic dissection of tree rings - a novel sampling tool for δ(13) C and δ(18) O studies.

Science.gov (United States)

Schollaen, Karina; Heinrich, Ingo; Helle, Gerhard

2014-02-01

UV-laser-based microscopic systems were utilized to dissect and sample organic tissue for stable isotope measurements from thin wood cross-sections. We tested UV-laser-based microscopic tissue dissection in practice for high-resolution isotopic analyses (δ(13) C/δ(18) O) on thin cross-sections from different tree species. The method allows serial isolation of tissue of any shape and from millimetre down to micrometre scales. On-screen pre-defined areas of interest were automatically dissected and collected for mass spectrometric analysis. Three examples of high-resolution isotopic analyses revealed that: in comparison to δ(13) C of xylem cells, woody ray parenchyma of deciduous trees have the same year-to-year variability, but reveal offsets that are opposite in sign depending on whether wholewood or cellulose is considered; high-resolution tree-ring δ(18) O profiles of Indonesian teak reflect monsoonal rainfall patterns and are sensitive to rainfall extremes caused by ENSO; and seasonal moisture signals in intra-tree-ring δ(18) O of white pine are weighted by nonlinear intra-annual growth dynamics. The applications demonstrate that the use of UV-laser-based microscopic dissection allows for sampling plant tissue at ultrahigh resolution and unprecedented precision. This new technique facilitates sampling for stable isotope analysis of anatomical plant traits like combined tree eco-physiological, wood anatomical and dendroclimatological studies. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Tracing anthropogenic thallium in soil using stable isotope compositions.

Science.gov (United States)

Kersten, Michael; Xiao, Tangfu; Kreissig, Katharina; Brett, Alex; Coles, Barry J; Rehkämper, Mark

2014-08-19

Thallium stable isotope data are used in this study, for the first time, to apportion Tl contamination in soils. In the late 1970s, a cement plant near Lengerich, Germany, emitted cement kiln dust (CKD) with high Tl contents, due to cocombustion of Tl-enriched pyrite roasting waste. Locally contaminated soil profiles were obtained down to 1 m depth and the samples are in accord with a binary mixing relationship in a diagram of Tl isotope compositions (expressed as ε(205)Tl, the deviation of the (205)Tl/(203)Tl ratio of a sample from the NIST SRM 997 Tl isotope standard in parts per 10(4)) versus 1/[Tl]. The inferred mixing endmembers are the geogenic background, as defined by isotopically light soils at depth (ε(205)Tl ≈ -4), and the Tl emissions, which produce Tl-enriched topsoils with ε(205)Tl as high as ±0. The latter interpretation is supported by analyses of the CKD, which is also characterized by ε(205)Tl ≈ ± 0, and the same ε(205)Tl value was found for a pyrite from the deposit that produced the cocombusted pyrite roasting waste. Additional measurements for samples from a locality in China, with outcrops of Tl sulfide mineralization and associated high natural Tl backgrounds, reveal significant isotope fractionation between soils (ε(205)Tl ≈ +0.4) and locally grown green cabbage (ε(205)Tl between -2.5 and -5.4). This demonstrates that biological isotope fractionation cannot explain the isotopically heavy Tl in the Lengerich topsoils and the latter are therefore clearly due to anthropogenic Tl emissions from cement processing. Our results thus establish that isotopic data can reinforce receptor modeling for the toxic trace metal Tl.

Metagenomic analysis of bat guano samples revealed the presence of viruses potentially carried by insects, among others by Apis mellifera in Hungary.

Science.gov (United States)

Zana, Brigitta; Kemenesi, Gábor; Urbán, Péter; Földes, Fanni; Görföl, Tamás; Estók, Péter; Boldogh, Sándor; Kurucz, Kornélia; Jakab, Ferenc

2018-03-01

The predominance of dietary viruses in bat guano samples had been described recently, suggesting a new opportunity to survey the prevalence and to detect new viruses of arthropods or even plant-infecting viruses circulating locally in the ecosystem. Here we describe the diversity of viruses belonging to the order Picornavirales in Hungarian insectivorous bat guano samples. The metagenomic analysis conducted on our samples has revealed the significant predominance of aphid lethal paralysis virus (ALPV) and Big Sioux River virus (BSRV) in Hungary for the first time. Phylogenetic analysis was used to clarify the relationship to previously identified ALPV strains infecting honey bees, showing that our strain possesses a close genetic relationship with the strains that have already been described as pathogenic to honey bees. Furthermore, studies have previously confirmed the ability of these viruses to replicate in adult honey bees; however, no signs related to these viruses have been revealed yet. With the identification of two recently described possibly honey bee infecting viruses for the first time in Hungary, our results might have importance for the health conditions of Hungarian honey bee colonies in the future.

The relationship between carbon stable isotope ratios of hatchling down and egg yolk in Black-headed Gulls

NARCIS (Netherlands)

Klaassen, M.R.J.; Baarspul, T.; Dekkers, T.; Van Tienen, P.

2004-01-01

We reconstructed the nutrient source for egg synthesis by sampling Black-headed Gull (Larus ridibundus) eggs for yolk, analyzing their carbon stable isotope ratio, and comparing that to hatchling down. Most of the variation in carbon stable isotope ratio was explained by differences between nests,

Consistent habitat segregation between sexes in the spider crabs Maja brachydactyla and Maja squinado (Brachyura, as revealed by stable isotopes

Directory of Open Access Journals (Sweden)

Guillermo Guerao

2016-03-01

Full Text Available Differences in the resource use patterns of males and females of the spider crab species Maja brachydactyla Balss, 1922 and M. squinado (Herbst, 1788 from several geographic areas (three in the Atlantic and two in the Mediterranean were studied through the analysis of stable isotopes of carbon and nitrogen in the exoskeleton of post-pubertal (adult specimens. Results confirmed that males and females from the same population usually did not differ in δ15N values and hence foraged at the same trophic level. In contrast, females were usually enriched in 13C as compared with males from the same population, thus suggesting that females use shallower habitats than males before the terminal moult. The results reported here also indicate that stable isotop.

Flask sample measurements for CO2, CH4 and CO using cavity ring-down spectrometry

Science.gov (United States)

Wang, J.-L.; Jacobson, G.; Rella, C. W.; Chang, C.-Y.; Liu, I.; Liu, W.-T.; Chew, C.; Ou-Yang, C.-F.; Liao, W.-C.; Chang, C.-C.

2013-08-01

In recent years, cavity ring-down spectrometry (CRDS) has been demonstrated to be a highly sensitive, stable and fast analytical technique for real-time in situ measurements of greenhouse gases. In this study, we propose the technique (which we call flask-CRDS) of analyzing whole air flask samples for CO2, CH4 and CO using a custom gas manifold designed to connect to a CRDS analyzer. Extremely stable measurements of these gases can be achieved over a large pressure range in the flask, from 175 to 760 Torr. The wide pressure range is conducive to flask sample measurement in three ways: (1) flask samples can be collected in low-pressure environments (e.g. high-altitude locations); (2) flask samples can be first analyzed for other trace gases with the remaining low-pressure sample for CRDS analysis of CO2, CH4 and CO; and (3) flask samples can be archived and re-analyzed for validation. The repeatability of this method (1σ of 0.07 ppm for CO2, 0.4 ppb for CH4, and 0.5 ppb for CO) was assessed by analyzing five canisters filled with the same air sample to a pressure of 200 Torr. An inter-comparison of the flask-CRDS data with in-situ CRDS measurements at a high-altitude mountain baseline station revealed excellent agreement, with differences of 0.10 ± 0.09 ppm (1σ) for CO2 and 0.9 ± 1.0 ppb for CH4. This study demonstrated that the flask-CRDS method was not only simple to build and operate but could also perform highly accurate and precise measurements of atmospheric CO2, CH4 and CO in flask samples.

Carbon and oxygen stable isotope and trace element studies in speleothems and across the J-K boundary, Central Italy

International Nuclear Information System (INIS)

Kudielka, G.

2001-07-01

Carbon and Oxygen stable isotope ratios of carbonates decisively depend on fractionation during physicochemical processes. Therefore, they represent a powerful tool to derive information on past conditions under which the carbonates formed. Isotope ratio mass spectrometry (IRMS) offers a large range of applications. This thesis presents two projects based upon investigation of carbon and oxygen stable isotope ratios combined with trace element abundances (determined by instrumental neutron activation analysis, INAA) in carbonates. (1) Palaeoclimatic investigation on speleothems from central Italy. Four speleothems from Grotta Grande del Vento, central Italy, were analyzed for stable isotope ratios and trace element abundances, and age dated to obtain a chronologically reliable stable isotope profile. The speleothems were sampled by means of a dental drill to gain a stable isotope profile with a 0.5 mm resolution, trace element abundances have been performed by INAA every 0.5 cm, and the samples for age dating were picked according to remarkable features in the stable isotope trends and analyzed by TIMS. The record covers the period from 93 ka until the early holocene with a hiatus lasting from 75 ka until 65.0 ka. Speleothem growth during the last glacial indicates moderate conditions in the Frasassi region back then. Comparison with speleothems from Ireland, France and northern Italy reveal a north-south slope in d18O, indicating, that the rain over central Italy mainly originates from the North Atlantic. Depletion of moisture in d18O during its continental trajectory is due to rainout, which primarily extracts the heavy isotopes. The stable isotope record is in good agreement with the high-resolution speleothem record from Soreq Cave, Israel. Distinct isotopic events coincide between 85 ka and 80 ka, between ∼ 60 ka and 50 ka and from the last glacial to the early holocene. An offset has been existing between the two records at any time. The speleothems of

Simultaneous determination of stable carbon, oxygen, and hydrogen isotopes in cellulose.

Science.gov (United States)

Loader, N J; Street-Perrott, F A; Daley, T J; Hughes, P D M; Kimak, A; Levanič, T; Mallon, G; Mauquoy, D; Robertson, I; Roland, T P; van Bellen, S; Ziehmer, M M; Leuenberger, M

2015-01-06

A technological development is described through which the stable carbon-, oxygen-, and nonexchangeable hydrogen-isotopic ratios (δ(13)C, δ(18)O, δ(2)H) are determined on a single carbohydrate (cellulose) sample with precision equivalent to conventional techniques (δ(13)C 0.15‰, δ(18)O 0.30‰, δ(2)H 3.0‰). This triple-isotope approach offers significant new research opportunities, most notably in physiology and medicine, isotope biogeochemistry, forensic science, and palaeoclimatology, when isotopic analysis of a common sample is desirable or when sample material is limited.

The origin of water in the primitive Moon as revealed by the lunar highlands samples

Science.gov (United States)

Barnes, Jessica J.; Tartèse, Romain; Anand, Mahesh; McCubbin, Francis M.; Franchi, Ian A.; Starkey, Natalie A.; Russell, Sara S.

2014-03-01

The recent discoveries of hydrogen (H) bearing species on the lunar surface and in samples derived from the lunar interior have necessitated a paradigm shift in our understanding of the water inventory of the Moon, which was previously considered to be a ‘bone-dry’ planetary body. Most sample-based studies have focused on assessing the water contents of the younger mare basalts and pyroclastic glasses, which are partial-melting products of the lunar mantle. In contrast, little attention has been paid to the inventory and source(s) of water in the lunar highlands rocks which are some of the oldest and most pristine materials available for laboratory investigations, and that have the potential to reveal the original history of water in the Earth-Moon system. Here, we report in-situ measurements of hydroxyl (OH) content and H isotopic composition of the mineral apatite from four lunar highlands samples (two norites, a troctolite, and a granite clast) collected during the Apollo missions. Apart from troctolite in which the measured OH contents in apatite are close to our analytical detection limit and its H isotopic composition appears to be severely compromised by secondary processes, we have measured up to ˜2200 ppm OH in the granite clast with a weighted average δD of ˜ -105±130‰, and up to ˜3400 ppm OH in the two norites (77215 and 78235) with weighted average δD values of -281±49‰ and -27±98‰, respectively. The apatites in the granite clast and the norites are characterised by higher OH contents than have been reported so far for highlands samples, and have H isotopic compositions similar to those of terrestrial materials and some carbonaceous chondrites, providing one of the strongest pieces of evidence yet for a common origin for water in the Earth-Moon system. In addition, the presence of water, of terrestrial affinity, in some samples of the earliest-formed lunar crust suggests that either primordial terrestrial water survived the aftermath

Small Tails Tell Tall Tales--Intra-Individual Variation in the Stable Isotope Values of Fish Fin.

Directory of Open Access Journals (Sweden)

Brian Hayden

Full Text Available Fish fin is a widely used, non-lethal sample material in studies using stable isotopes to assess the ecology of fishes. However, fish fin is composed of two distinct tissues (ray and membrane which may have different stable isotope values and are not homogeneously distributed within a fin. As such, estimates of the stable isotope values of a fish may vary according to the section of fin sampled.To assess the magnitude of this variation, we analysed carbon (δ13C, nitrogen (δ15N, hydrogen (δ2H and oxygen (δ18O stable isotopes of caudal fin from juvenile, riverine stages of Atlantic salmon (Salmo salar and brown trout (Salmo trutta. Individual fins were sub-sectioned into tip, mid and base, of which a further subset were divided into ray and membrane.Isotope variation between fin sections, evident in all four elements, was primarily related to differences between ray and membrane. Base sections were13C depleted relative to tip (~1‰ with equivalent variation evident between ray and membrane. A similar trend was evident in δ2H, though the degree of variation was far greater (~10‰. Base and ray sections were 18O enriched (~2‰ relative to tip and membrane, respectively. Ray and membrane sections displayed longitudinal variation in 15N mirroring that of composite fin (~1‰, indicating that variation in15N values was likely related to ontogenetic variation.To account for the effects of intra-fin variability in stable isotope analyses we suggest that researchers sampling fish fin, in increasing priority, 1 also analyse muscle (or liver tissue from a subsample of fish to calibrate their data, or 2 standardize sampling by selecting tissue only from the extreme tip of a fin, or 3 homogenize fins prior to analysis.

High-resolution stable isotope monitoring reveals differential vegetation-soil water feedbacks among plant functional types

Science.gov (United States)

Volkmann, T. H. M.; Haberer, K.; Troch, P. A. A.; Gessler, A.; Weiler, M.

2016-12-01

Understanding the linked dynamics of rain water recharge to soils and its utilization by plants is critical for predicting the impact of climate and land use changes on the productivity of ecosystems and the hydrologic cycle. While plants require vast quantities of water from the soil to sustain growth and function, they exert important direct and indirect controls on the movement of water through the rooted soil horizons, thereby potentially affecting their own resource availability. However, the specific ecohydrological belowground processes associated with different plant types and their rooting systems have been difficult to quantify with traditional methods. Here, we report on the use of techniques for monitoring stable isotopes in soil and plant water pools that allow us to track water infiltration and root uptake dynamics non-destructively and in high resolution. The techniques were applied in controlled rain pulse experiments with distinct plant types (grass, deciduous trees, grapevine) that we let develop on an initially uniform soil for two years. Our results show that plant species and types differed widely in their plasticity and pattern of root uptake under variable water availability. Thereby, and through notably co-acting indirect effects related to differential root system traits and co-evolution of soil properties, the different plants induced contrasting hydrological dynamics in the soil they had inhabited for only a short period of time. Taken together, our data suggest that the studied soil-vegetation systems evolved a positive infiltration-uptake feedback in which hydrological flow pathways underlying different species diverged in a way that complemented their specific water utilization strategy. Such a feedback could present an indirect competitive mechanism by which plants improve their own water supply and modulate hydrological cycling at the land surface. The ability to directly measure this feedback using in situ isotope methodology

LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

Data.gov (United States)

National Aeronautics and Space Administration — This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest canopy...

LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest...

Springtime carbon emission episodes at the Gosan background site revealed by total carbon, stable carbon isotopic composition, and thermal characteristics of carbonaceous particles

Directory of Open Access Journals (Sweden)

J. Jung

2011-11-01

Full Text Available In order to investigate the emission of carbonaceous aerosols at the Gosan background super-site (33.17° N, 126.10° E in East Asia, total suspended particles (TSP were collected during spring of 2007 and 2008 and analyzed for particulate organic carbon, elemental carbon, total carbon (TC, total nitrogen (TN, and stable carbon isotopic composition (δ¹³C of TC. The stable carbon isotopic composition of TC (δ¹³C_TC was found to be lowest during pollen emission episodes (range: −26.2‰ to −23.5‰, avg. −25.2 ± 0.9‰, approaching those of the airborne pollen (−28.0‰ collected at the Gosan site. Based on a carbon isotope mass balance equation, we found that ~42% of TC in the TSP samples during the pollen episodes was attributed to airborne pollen from Japanese cedar trees planted around tangerine farms in Jeju Island. A negative correlation between the citric acid-carbon/TC ratios and δ¹³C_TC was obtained during the pollen episodes. These results suggest that citric acid emitted from tangerine fruit may be adsorbed on the airborne pollen and then transported to the Gosan site. Thermal evolution patterns of organic carbon during the pollen episodes were characterized by high OC evolution in the OC2 temperature step (450 °C. Since thermal evolution patterns of organic aerosols are highly influenced by their molecular weight, they can be used as additional information on the formation of secondary organic aerosols and the effect of aging of organic aerosols during the long-range atmospheric transport and sources of organic aerosols.

First stable isotope analysis of Asiatic wild ass tail hair from the Mongolian Gobi.

Science.gov (United States)

Horacek, Micha; Sturm, Martina Burnik; Kaczensky, Petra

Stable isotope analysis has become a powerful tool to study feeding ecology, water use or movement pattern in contemporary, historic and ancient species. Certain hair and teeth grow continuously, and when sampled longitudinally can provide temporally explicit information on dietary regime and movement pattern. In an initial trial, we analysed a tail sample of an Asiatic wild ass ( Equus hemionus ) from the Mongolian Gobi. We found seasonal variations in H, C and N isotope patterns, likely being the result of temporal variations in available feeds, water supply and possibly physiological status. Thus stable isotope analysis shows promise to study the comparative ecology of the three autochthonous equid species in the Mongolian Gobi.

Stable Boundary Layer Issues

OpenAIRE

Steeneveld, G.J.

2012-01-01

Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The development of robust stable boundary layer parameterizations for use in NWP and climate models is hampered by the multiplicity of processes and their unknown interactions. As a result, these models suffer ...

Possible THz gain in superlattices at a stable operation point

DEFF Research Database (Denmark)

Wacker, Andreas; Allen, S. J.; Scott, J. S.

1997-01-01

We demonstrate that semiconductor superlattices may provide gain at THz frequencies at an operation point which is stable against fluctuations at lower frequency. While an explicit experimental demonstration for the sample considered could not be achieved, the underlying principle of quantum resp...... response is quite general and may prove successful for differently designed superlattices....

Model of the transverse modes of stable and unstable porro–prism resonators using symmetry considerations

CSIR Research Space (South Africa)

Burger, L

2007-01-01

Full Text Available of this type of resonator. Further use of the model reveals the formation of more complex beam patterns, and the nature of these patterns is investigated. Also, the output of stable and unstable resonator modes is presented....

Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography–mass spectrometry and stable labeled isotope as internal standard

International Nuclear Information System (INIS)

Varlet, V.; Smith, F.; Froidmont, S. de; Dominguez, A.; Rinaldi, A.; Augsburger, M.; Mangin, P.; Grabherr, S.

2013-01-01

Graphical abstract: -- Highlights: •We developed a method for CO 2 analysis in cardiac samples and quantification by 13 CO 2 . •This method was fully validated by accuracy profile. •We have applied this method to perform CO 2 precise quantification for forensic applications. •Context of the death could be documented following CO 2 concentrations. -- Abstract: A novel approach to measure carbon dioxide (CO 2 ) in gaseous samples, based on a precise and accurate quantification by 13 CO 2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography–mass spectrometry (HS-GC–MS) method applicable in the routine determination of CO 2 . The main drawback of the GC methods discussed in the literature for CO 2 measurement is the lack of a specific internal standard necessary to perform quantification. CO 2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ( 13 CO 2 ) on the basis of the stoichiometric formation of CO 2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH 13 CO 3 ). This method allows a precise measurement of CO 2 concentration and was validated on various human postmortem gas samples in order to study its efficiency

Wall-crossing between stable and co-stable ADHM data

Science.gov (United States)

Ohkawa, Ryo

2018-06-01

We prove formula between Nekrasov partition functions defined from stable and co-stable ADHM data for the plane following method by Nakajima and Yoshioka (Kyoto J Math 51(2):263-335, 2011) based on the theory of wall-crossing formula developed by Mochizuki (Donaldson type invariants for algebraic surfaces: transition of moduli stacks, Lecture notes in mathematics, vol 1972, Springer, Berlin, 2009). This formula is similar to conjectures by Ito et al. [J High Energy Phys 2013(5):045, 2013, (4.1), (4.2)] for A1 singularity.

New developments in the use of stable activable tracers in environmental science

International Nuclear Information System (INIS)

Loveland, W.; Keasler, K.; Ghannam, L.; Borovik, A.

1980-01-01

Recent developments in the use of stable activable tracers (SATs) in environmental science are reported. (A stable activable tracer is a stable material injected into a system under study and whose concentration is measured by post-sampling activation analysis.) The activable nuclear parts of the tracers studied have been rare earth nuclides with short-lived activation products or Cu. To trace the fate of fluid-bound pollutants (and/or water masses) in marine waters, we have used anionic DTPA complexes of the rare earths. These tracers were shown to be stable (80 to 90% nondissociated) in extensive laboratory tests involving solutions of the tracer in estuarine water including large amounts of marine sediments. Results of a field study in which the flushing time and other hydrological characteristics of an estuarine marina were measured by simultaneously using a fluorescent dye and a SAT are presented. To trace the path of potentially toxic organic molecules, three stable activable tracers, dysprosium(III)-trisacetylacetonate DY(acac) 3 3H 2 O), dysprosium(III)-trisdibenzoylmethane (DY(dbm) 3 H 2 O and copper oxinate Cu (C 9 H 6 ON) 2 were synthesized. Their octanol/water partition coefficients and their solubility in water were measured and used to correlate the tracer species and its biological activity with that of known toxic materials. In a project to demonstrate the simple use of SATs to trace the origin of common insecticides and herbicides, seven common insecticides and herbicides were marked with anionic rare earth DTPA complexes and shown to be detectable at dilutions of 1 part in 10 12 . Two arsenical herbicides were chosen for further study and the tracer/herbicide ratio was shown to remain constant in samples of herbicide material collected on plant surfaces and runoff waters in the environment for long periods

Stable isotope ratios of marijuana. I. Carbon and nitrogen stable isotopes describe growth conditions.

Science.gov (United States)

West, Jason B; Hurley, Janet M; Ehleringer, James R

2009-01-01

There remains significant uncertainty in illicit marijuana cultivation. We analyzed the delta(13)C and delta(15)N of 508 domestic samples from known U.S.A. counties, 31 seized from a single location, 5 samples grown in Mexico and Colombia, and 10 northwest border seizures. For a subset, inflorescences and leaves were analyzed separately. These data revealed a strong correspondence, with inflorescences having slightly higher delta(13)C and delta(15)N values than leaves. A framework for interpreting these results is introduced and evaluated. Samples identified as outdoor-grown by delta(13)C were generally recorded as such by the Drug Enforcement Administration (DEA). DEA-classified indoor-grown samples had the most negative delta(13)C values, consistent with indoor cultivation, although many were also in the outdoor-grown domain. Delta(15)N indicated a wide range of fertilizers across the dataset. Samples seized at the single location suggested multiple sources. Northwest border delta(13)C values suggested indoor growth, whereas for the Mexican and Colombian samples they indicated outdoor growth.

Pig Farmers’ Homes Harbor More Diverse Airborne Bacterial Communities Than Pig Stables or Suburban Homes

Directory of Open Access Journals (Sweden)

Ditte V. Vestergaard

2018-05-01

Full Text Available Airborne bacterial communities are subject to conditions ill-suited to microbial activity and growth. In spite of this, air is an important transfer medium for bacteria, with the bacteria in indoor air having potentially major consequences for the health of a building’s occupants. A major example is the decreased diversity and altered composition of indoor airborne microbial communities as a proposed explanation for the increasing prevalence of asthma and allergies worldwide. Previous research has shown that living on a farm confers protection against development of asthma and allergies, with airborne bacteria suggested as playing a role in this protective effect. However, the composition of this beneficial microbial community has still not been identified. We sampled settled airborne dust using a passive dust sampler from Danish pig stables, associated farmers’ homes, and from suburban homes (267 samples in total and carried out quantitative PCR measurements of bacterial abundance and MiSeq sequencing of the V3–V4 region of bacterial 16S rRNA genes found in these samples. Airborne bacteria had a greater diversity and were significantly more abundant in pig stables and farmers’ homes than suburban homes (Wilcoxon rank sum test P < 0.05. Moreover, bacterial taxa previously suggested to contribute to a protective effect had significantly higher relative and absolute abundance in pig stables and farmers’ homes than in suburban homes (ALDEx2 with P < 0.05, including Firmicutes, Peptostreptococcaceae, Prevotellaceae, Lachnospiraceae, Ruminococcaceae, Ruminiclostridium, and Lactobacillus. Pig stables had significantly lower airborne bacterial diversity than farmers’ homes, and there was no discernable direct transfer of airborne bacteria from stable to home. This study identifies differences in indoor airborne bacterial communities that may be an important component of this putative protective effect, while showing that pig stables

Pig Farmers’ Homes Harbor More Diverse Airborne Bacterial Communities Than Pig Stables or Suburban Homes

Science.gov (United States)

Vestergaard, Ditte V.; Holst, Gitte J.; Basinas, Ioannis; Elholm, Grethe; Schlünssen, Vivi; Linneberg, Allan; Šantl-Temkiv, Tina; Finster, Kai; Sigsgaard, Torben; Marshall, Ian P. G.

2018-01-01

Airborne bacterial communities are subject to conditions ill-suited to microbial activity and growth. In spite of this, air is an important transfer medium for bacteria, with the bacteria in indoor air having potentially major consequences for the health of a building’s occupants. A major example is the decreased diversity and altered composition of indoor airborne microbial communities as a proposed explanation for the increasing prevalence of asthma and allergies worldwide. Previous research has shown that living on a farm confers protection against development of asthma and allergies, with airborne bacteria suggested as playing a role in this protective effect. However, the composition of this beneficial microbial community has still not been identified. We sampled settled airborne dust using a passive dust sampler from Danish pig stables, associated farmers’ homes, and from suburban homes (267 samples in total) and carried out quantitative PCR measurements of bacterial abundance and MiSeq sequencing of the V3–V4 region of bacterial 16S rRNA genes found in these samples. Airborne bacteria had a greater diversity and were significantly more abundant in pig stables and farmers’ homes than suburban homes (Wilcoxon rank sum test P < 0.05). Moreover, bacterial taxa previously suggested to contribute to a protective effect had significantly higher relative and absolute abundance in pig stables and farmers’ homes than in suburban homes (ALDEx2 with P < 0.05), including Firmicutes, Peptostreptococcaceae, Prevotellaceae, Lachnospiraceae, Ruminococcaceae, Ruminiclostridium, and Lactobacillus. Pig stables had significantly lower airborne bacterial diversity than farmers’ homes, and there was no discernable direct transfer of airborne bacteria from stable to home. This study identifies differences in indoor airborne bacterial communities that may be an important component of this putative protective effect, while showing that pig stables themselves do not appear

Pig Farmers' Homes Harbor More Diverse Airborne Bacterial Communities Than Pig Stables or Suburban Homes.

Science.gov (United States)

Vestergaard, Ditte V; Holst, Gitte J; Basinas, Ioannis; Elholm, Grethe; Schlünssen, Vivi; Linneberg, Allan; Šantl-Temkiv, Tina; Finster, Kai; Sigsgaard, Torben; Marshall, Ian P G

2018-01-01

Airborne bacterial communities are subject to conditions ill-suited to microbial activity and growth. In spite of this, air is an important transfer medium for bacteria, with the bacteria in indoor air having potentially major consequences for the health of a building's occupants. A major example is the decreased diversity and altered composition of indoor airborne microbial communities as a proposed explanation for the increasing prevalence of asthma and allergies worldwide. Previous research has shown that living on a farm confers protection against development of asthma and allergies, with airborne bacteria suggested as playing a role in this protective effect. However, the composition of this beneficial microbial community has still not been identified. We sampled settled airborne dust using a passive dust sampler from Danish pig stables, associated farmers' homes, and from suburban homes (267 samples in total) and carried out quantitative PCR measurements of bacterial abundance and MiSeq sequencing of the V3-V4 region of bacterial 16S rRNA genes found in these samples. Airborne bacteria had a greater diversity and were significantly more abundant in pig stables and farmers' homes than suburban homes (Wilcoxon rank sum test P < 0.05). Moreover, bacterial taxa previously suggested to contribute to a protective effect had significantly higher relative and absolute abundance in pig stables and farmers' homes than in suburban homes (ALDEx2 with P < 0.05), including Firmicutes, Peptostreptococcaceae, Prevotellaceae, Lachnospiraceae, Ruminococcaceae, Ruminiclostridium , and Lactobacillus . Pig stables had significantly lower airborne bacterial diversity than farmers' homes, and there was no discernable direct transfer of airborne bacteria from stable to home. This study identifies differences in indoor airborne bacterial communities that may be an important component of this putative protective effect, while showing that pig stables themselves do not appear to

Synthesis and spectroscopic studies of stable aqueous dispersion of silver nanoparticles.

Science.gov (United States)

El-Shishtawy, Reda M; Asiri, Abdullah M; Al-Otaibi, Maha M

2011-09-01

A facile approach for the synthesis of stable aqueous dispersion of silver nanoparticles (AgNPs) using glucose as the reducing agent in water/micelles system, in which cetyltrimethylammonium bromide (CTAB) was used as capping agent (stabilizer) is described. The evolution of plasmon band of AgNPs was monitored under different conditions such as (a) concentration of sodium hydroxide, (b) concentration of glucose, (c) concentration of silver nitrate (d) concentration of CTAB, and (e) reaction time. AgNPs were characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), fluorescence spectroscopy and FT-IR spectroscopy. The results revealed an easy and viable strategy for obtaining stable aqueous dispersion of AgNPs with well controlled shape and size below 30 nm in diameter. Copyright © 2011 Elsevier B.V. All rights reserved.

Angina Pectoris (Stable Angina)

Science.gov (United States)

... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Angina Pectoris (Stable Angina) Updated:Aug 21,2017 You may have heard the term “angina pectoris” or “stable angina” in your doctor’s office, ...

40 CFR 90.413 - Exhaust sample procedure-gaseous components.

Science.gov (United States)

2010-07-01

...-analysis values. (3) Measure and record HC, CO, CO2, and NOX concentrations in the exhaust sample bag(s...-analysis values. (7) Collect background HC, CO, CO2, and NOX in a sample bag (for dilute exhaust sampling...: (1) For dilute grab (“bag”) sample analysis, the analyzer response must be stable at greater than 99...

Phylogenetic variation of Aggregatibacter actinomycetemcomitans serotype e reveals an aberrant distinct evolutionary stable lineage

NARCIS (Netherlands)

van der Reijden, Wil A.; Brunner, Jorg; Bosch-Tijhof, Carolien J.; van Trappen, Stefanie; Rijnsburger, Martine C.; de Graaff, Marcel P. W.; van Winkelhoff, Arie J.; Cleenwerck, Ilse; de Vos, Paul

2010-01-01

The periodontal pathogen Aggregatibacter actinomycetemcomitans that comprises six serotypes (a-f), is often identified by PCR-based techniques targeting the 16S rRNA gene. In this study, 16S rRNA gene sequence analysis revealed an aberrant cluster of 19 strains within serotype e, denoted as serotype

Analysis of sequences from field samples reveals the presence of the recently described pepper vein yellows virus (genus Polerovirus) in six additional countries.

Science.gov (United States)

Knierim, Dennis; Tsai, Wen-Shi; Kenyon, Lawrence

2013-06-01

Polerovirus infection was detected by reverse transcription polymerase chain reaction (RT-PCR) in 29 pepper plants (Capsicum spp.) and one black nightshade plant (Solanum nigrum) sample collected from fields in India, Indonesia, Mali, Philippines, Thailand and Taiwan. At least two representative samples for each country were selected to generate a general polerovirus RT-PCR product of 1.4 kb length for sequencing. Sequence analysis of the partial genome sequences revealed the presence of pepper vein yellows virus (PeVYV) in all 13 samples. A 1990 Australian herbarium sample of pepper described by serological means as infected with capsicum yellows virus (CYV) was identified by sequence analysis of a partial CP sequence as probably infected with a potato leaf roll virus (PLRV) isolate.

Stable isotope values in pup vibrissae reveal geographic variation in diets of gestating Steller sea lions Eumetopias jubatus

Science.gov (United States)

Scherer, Rick D.; Doll, Andrew C.; Rea, Lorrie D.; Christ, Aaron M.; Stricker, Craig A.; Witteveen, Briana; Kline, Thomas C.; Kurle, Carolyn M.; Wunder, Michael B.

2015-01-01

Multiple factors, including limitation in food resources, have been proposed as possible causes for the lack of recovery of the endangered western segment of the Steller sea lion population in the United States. Because maternal body condition has important consequences on fetal development and neonatal survival, the diets of pregnant females may be particularly important in regulating population sizes. We used the stable carbon and nitrogen isotope values of vibrissae from Steller sea lion pups as an indirect indicator of maternal diets during gestation. Combining these data with isotope data from potential prey species in a Bayesian mixing model, we generated proportional estimates of dietary consumption for key prey. Our analysis indicated that females in the most westerly metapopulations relied heavily on Atka mackerel and squid, whereas females inhabiting the Gulf of Alaska region had a fairly mixed diet, and the metapopulation of Southeast Alaska showed a strong reliance on forage fish. These results are similar to previous data from scat collections; however, they indicate a possible under-representation of soft-bodied prey (squid) or prey with fragile skeletons (forage fish) from analyses of data from scats. This study supports the utility of stable isotope modeling in predicting diet composition in gestating adult female Steller sea lions during winter, using pup vibrissae.

Abundance of four sulfur mustard-DNA adducts ex vivo and in vivo revealed by simultaneous quantification in stable isotope dilution-ultrahigh performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Yue, Lijun; Wei, Yuxia; Chen, Jia; Shi, Huiqin; Liu, Qin; Zhang, Yajiao; He, Jun; Guo, Lei; Zhang, Tingfen; Xie, Jianwei; Peng, Shuangqing

2014-04-21

Sulfur mustard (SM) is a highly reactive alkylating vesicant and causes blisters upon contact with skin, eyes, and respiratory organs. It covalently links with DNAs by forming four mono- or cross-link adducts. In this article, the reference standards of SM-DNA adducts and deuterated analogues were first synthesized with simplified procedures containing only one or two steps and using less toxic chemical 2-(2-chloroethylthio)ethanol or nontoxic chemical thiodiglycol as starting materials. A sensitive and high-throughput simultaneous quantification method of N(7)-[2-[(2-hydroxyethyl)thio]-ethyl]guanine (N(7)-HETEG), O(6)-[2-[(2-hydroxyethyl)thio]-ethyl]guanine (O(6)-HETEG), N(3)-[2-[(2-hydroxyethyl)thio]-ethyl]adenine (N(3)-HETEA), and bis[2-(guanin-7-yl)ethyl]sulfide (Bis-G) in the Sprague-Dawley rat derma samples was developed by stable isotope dilution-ultrahigh performance liquid chromatography-tandem mass spectrometry (ID-UPLC-MS/MS) with the aim of revealing the real metabolic behaviors of four adducts. The method was validated, the limit of detection (S/N ratio greater than 10) was 0.01, 0.002, 0.04, and 0.11 fmol on column for N(7)-HETEG, O(6)-HETEG, Bis-G, and N(3)-HETEA, respectively, and the lower limit of quantification (S/N ratio greater than 20) was 0.04, 0.01, 0.12, and 0.33 fmol on column for N(7)-HETEG, O(6)-HETEG, Bis-G, and N(3)-HETEA, respectively. The accuracy of this method was determined to be 76% to 129% (n = 3), and both the interday (n = 6) and intraday (n = 7) precisions were less than 10%. The method was further applied for the quantifications of four adducts in the derma of adult male Sprague-Dawley rats exposed to SM ex vivo and in vivo, and all adducts had time- and dose-effect relationships. To the best of our knowledge, this is the first time that the real presented status of four DNA adducts was simultaneously revealed by the MS-based method, in which Bis-G showed much higher abundance than the result previously reported and N(3

The stable Cr isotopic compositions of chondrites and silicate planetary reservoirs

Science.gov (United States)

Schoenberg, Ronny; Merdian, Alexandra; Holmden, Chris; Kleinhanns, Ilka C.; Haßler, Kathrin; Wille, Martin; Reitter, Elmar

2016-06-01

The depletion of chromium in Earth's mantle (∼2700 ppm) in comparison to chondrites (∼4400 ppm) indicates significant incorporation of chromium into the core during our planet's metal-silicate differentiation, assuming that there was no significant escape of the moderately volatile element chromium during the accretionary phase of Earth. Stable Cr isotope compositions - expressed as the ‰-difference in 53Cr/52Cr from the terrestrial reference material SRM979 (δ53/52CrSRM979 values) - of planetary silicate reservoirs might thus yield information about the conditions of planetary metal segregation processes when compared to chondrites. The stable Cr isotopic compositions of 7 carbonaceous chondrites, 11 ordinary chondrites, 5 HED achondrites and 2 martian meteorites determined by a double spike MC-ICP-MS method are within uncertainties indistinguishable from each other and from the previously determined δ53/52CrSRM979 value of -0.124 ± 0.101‰ for the igneous silicate Earth. Extensive quality tests support the accuracy of the stable Cr isotope determinations of various meteorites and terrestrial silicates reported here. The uniformity in stable Cr isotope compositions of samples from planetary silicate mantles and undifferentiated meteorites indicates that metal-silicate differentiation of Earth, Mars and the HED parent body did not cause measurable stable Cr isotope fractionation between these two reservoirs. Our results also imply that the accretionary disc, at least in the inner solar system, was homogeneous in its stable Cr isotopic composition and that potential volatility loss of chromium during accretion of the terrestrial planets was not accompanied by measurable stable isotopic fractionation. Small but reproducible variations in δ53/52CrSRM979 values of terrestrial magmatic rocks point to natural stable Cr isotope variations within Earth's silicate reservoirs. Further and more detailed studies are required to investigate whether silicate

Automated determination of the stable carbon isotopic composition (δ13C) of total dissolved inorganic carbon (DIC) and total nonpurgeable dissolved organic carbon (DOC) in aqueous samples: RSIL lab codes 1851 and 1852

Science.gov (United States)

Révész, Kinga M.; Doctor, Daniel H.

2014-01-01

The purposes of the Reston Stable Isotope Laboratory (RSIL) lab codes 1851 and 1852 are to determine the total carbon mass and the ratio of the stable isotopes of carbon (δ13C) for total dissolved inorganic carbon (DIC, lab code 1851) and total nonpurgeable dissolved organic carbon (DOC, lab code 1852) in aqueous samples. The analysis procedure is automated according to a method that utilizes a total carbon analyzer as a peripheral sample preparation device for analysis of carbon dioxide (CO2) gas by a continuous-flow isotope ratio mass spectrometer (CF-IRMS). The carbon analyzer produces CO2 and determines the carbon mass in parts per million (ppm) of DIC and DOC in each sample separately, and the CF-IRMS determines the carbon isotope ratio of the produced CO2. This configuration provides a fully automated analysis of total carbon mass and δ13C with no operator intervention, additional sample preparation, or other manual analysis. To determine the DIC, the carbon analyzer transfers a specified sample volume to a heated (70 °C) reaction vessel with a preprogrammed volume of 10% phosphoric acid (H3PO4), which allows the carbonate and bicarbonate species in the sample to dissociate to CO2. The CO2 from the reacted sample is subsequently purged with a flow of helium gas that sweeps the CO2 through an infrared CO2 detector and quantifies the CO2. The CO2 is then carried through a high-temperature (650 °C) scrubber reactor, a series of water traps, and ultimately to the inlet of the mass spectrometer. For the analysis of total dissolved organic carbon, the carbon analyzer performs a second step on the sample in the heated reaction vessel during which a preprogrammed volume of sodium persulfate (Na2S2O8) is added, and the hydroxyl radicals oxidize the organics to CO2. Samples containing 2 ppm to 30,000 ppm of carbon are analyzed. The precision of the carbon isotope analysis is within 0.3 per mill for DIC, and within 0.5 per mill for DOC.

Using Stable Isotopes of Carbon and Nitrogen to Evaluate Trophic Interactions in Aquatic Environments

Science.gov (United States)

Christensen, David R.; LaRoche, Andrew

2012-01-01

This paper describes a series of laboratory exercises for upper level biology courses, independent research and/or honors programs. Students sampled fish from a local water body with the assistance of a local fish and wildlife agency. Tissue samples from collected fish were utilized to obtain estimates of the stable isotopes delta[superscript 13]C…

Normal modified stable processes

DEFF Research Database (Denmark)

Barndorff-Nielsen, Ole Eiler; Shephard, N.

2002-01-01

Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process......This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...

No influence of CO2 on stable isotope analyses of soil waters with off-axis integrated cavity output spectroscopy (OA-ICOS).

Science.gov (United States)

Sprenger, Matthias; Tetzlaff, Doerthe; Soulsby, Chris

2017-03-15

It was recently shown that the presence of CO 2 affects the stable isotope (δ 2 H and δ 18 O values) analysis of water vapor via Wavelength-Scanned Cavity Ring-Down Spectroscopy. Here, we test how much CO 2 is emitted from soil samples and if the CO 2 in the headspace influences the isotope analysis with the direct equilibration method by Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS). The headspace above different amounts of sparkling water was sampled, and its stable isotopic composition (δ 2 H and δ 18 O values) and CO 2 concentration were measured by direct equilibration and by gas chromatography, respectively. In addition, the headspace above soil samples was analyzed in the same way. Furthermore, the gravimetric water content and the loss on ignition were measured for the soil samples. The experiment with the sparkling water showed that CO 2 does not influence the stable isotope analysis by OA-ICOS. CO 2 was emitted from the soil samples and correlated with the isotopic fractionation signal, but no causal relationship between the two was determined. Instead, the fractionation signal in pore water isotopes can be explained by soil evaporation and the CO 2 can be related to soil moisture and organic matter which both enhance microbial activity. We found, despite the high CO 2 emissions from soil samples, no need for a post-correction of the pore water stable isotope analysis results, since there is no relation between CO 2 concentrations and the stable isotope results of vapor samples obtained with OA-ICOS. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd.

Numerically stable algorithm for combining census and sample estimates with the multivariate composite estimator

Science.gov (United States)

R. L. Czaplewski

2009-01-01

The minimum variance multivariate composite estimator is a relatively simple sequential estimator for complex sampling designs (Czaplewski 2009). Such designs combine a probability sample of expensive field data with multiple censuses and/or samples of relatively inexpensive multi-sensor, multi-resolution remotely sensed data. Unfortunately, the multivariate composite...

Uses of stable isotopes

International Nuclear Information System (INIS)

Axente, Damian

1998-01-01

The most important fields of stable isotope use with examples are presented. These are: 1. Isotope dilution analysis: trace analysis, measurements of volumes and masses; 2. Stable isotopes as tracers: transport phenomena, environmental studies, agricultural research, authentication of products and objects, archaeometry, studies of reaction mechanisms, structure and function determination of complex biological entities, studies of metabolism, breath test for diagnostic; 3. Isotope equilibrium effects: measurement of equilibrium effects, investigation of equilibrium conditions, mechanism of drug action, study of natural processes, water cycle, temperature measurements; 4. Stable isotope for advanced nuclear reactors: uranium nitride with 15 N as nuclear fuel, 157 Gd for reactor control. In spite of some difficulties of stable isotope use, particularly related to the analytical techniques, which are slow and expensive, the number of papers reporting on this subject is steadily growing as well as the number of scientific meetings organized by International Isotope Section and IAEA, Gordon Conferences, and regional meeting in Germany, France, etc. Stable isotope application development on large scale is determined by improving their production technologies as well as those of labeled compound and the analytical techniques. (author)

Stable water isotopologue ratios in fog and cloud droplets of liquid clouds are not size-dependent

Science.gov (United States)

Spiegel, J.K.; Aemisegger, F.; Scholl, M.; Wienhold, F.G.; Collett, J.L.; Lee, T.; van Pinxteren, D.; Mertes, S.; Tilgner, A.; Herrmann, H.; Werner, Roland A.; Buchmann, N.; Eugster, W.

2012-01-01

In this work, we present the first observations of stable water isotopologue ratios in cloud droplets of different sizes collected simultaneously. We address the question whether the isotope ratio of droplets in a liquid cloud varies as a function of droplet size. Samples were collected from a ground intercepted cloud (= fog) during the Hill Cap Cloud Thuringia 2010 campaign (HCCT-2010) using a three-stage Caltech Active Strand Cloud water Collector (CASCC). An instrument test revealed that no artificial isotopic fractionation occurs during sample collection with the CASCC. Furthermore, we could experimentally confirm the hypothesis that the δ values of cloud droplets of the relevant droplet sizes (μm-range) were not significantly different and thus can be assumed to be in isotopic equilibrium immediately with the surrounding water vapor. However, during the dissolution period of the cloud, when the supersaturation inside the cloud decreased and the cloud began to clear, differences in isotope ratios of the different droplet sizes tended to be larger. This is likely to result from the cloud's heterogeneity, implying that larger and smaller cloud droplets have been collected at different moments in time, delivering isotope ratios from different collection times.

Stable water isotopologue ratios in fog and cloud droplets of liquid clouds are not size-dependent

Directory of Open Access Journals (Sweden)

J. K. Spiegel

2012-10-01

Full Text Available In this work, we present the first observations of stable water isotopologue ratios in cloud droplets of different sizes collected simultaneously. We address the question whether the isotope ratio of droplets in a liquid cloud varies as a function of droplet size. Samples were collected from a ground intercepted cloud (= fog during the Hill Cap Cloud Thuringia 2010 campaign (HCCT-2010 using a three-stage Caltech Active Strand Cloud water Collector (CASCC. An instrument test revealed that no artificial isotopic fractionation occurs during sample collection with the CASCC. Furthermore, we could experimentally confirm the hypothesis that the δ values of cloud droplets of the relevant droplet sizes (μm-range were not significantly different and thus can be assumed to be in isotopic equilibrium immediately with the surrounding water vapor. However, during the dissolution period of the cloud, when the supersaturation inside the cloud decreased and the cloud began to clear, differences in isotope ratios of the different droplet sizes tended to be larger. This is likely to result from the cloud's heterogeneity, implying that larger and smaller cloud droplets have been collected at different moments in time, delivering isotope ratios from different collection times.

Stable isotopes labelled compounds

International Nuclear Information System (INIS)

1982-09-01

The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

Stable Boundary Layer Issues

NARCIS (Netherlands)

Steeneveld, G.J.

2012-01-01

Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

Stable electroluminescence from passivated nano-crystalline porous silicon using undecylenic acid

Science.gov (United States)

Gelloz, B.; Sano, H.; Boukherroub, R.; Wayner, D. D. M.; Lockwood, D. J.; Koshida, N.

2005-06-01

Stabilization of electroluminescence from nanocrystalline porous silicon diodes has been achieved by replacing silicon-hydrogen bonds terminating the surface of nanocrystalline silicon with more stable silicon-carbon (Si-C) bonds. Hydrosilylation of the surface of partially and anodically oxidized porous silicon samples was thermally induced at about 90 °C using various different organic molecules. Devices whose surface have been modified with stable covalent bonds shows no degradation in the EL efficiency and EL output intensity under DC operation for several hours. The enhanced stability can be attributed to the high chemical resistance of Si-C bonds against current-induced surface oxidation associated with the generation of nonradiative defects. Although devices treated with 1-decene exhibit reduced EL efficiency and brightness compared to untreatred devices, other molecules, such as ethyl-undecylenate and particularly undecylenic acid provide stable and more efficient visible electroluminescence at room temperature. Undecylenic acid provides EL brightness as high as that of an untreated device.

Lowering coefficient of friction in Cu alloys with stable gradient nanostructures.

Science.gov (United States)

Chen, Xiang; Han, Zhong; Li, Xiuyan; Lu, K

2016-12-01

The coefficient of friction (COF) of metals is usually high, primarily because frictional contacts induce plastic deformation underneath the wear surface, resulting in surface roughening and formation of delaminating tribolayers. Lowering the COF of metals is crucial for improving the reliability and efficiency of metal contacts in engineering applications but is technically challenging. Refining the metals' grains to nanoscale cannot reduce dry-sliding COFs, although their hardness may be elevated many times. We report that a submillimeter-thick stable gradient nanograined surface layer enables a significant reduction in the COF of a Cu alloy under high-load dry sliding, from 0.64 (coarse-grained samples) to 0.29, which is smaller than the COFs of many ceramics. The unprecedented stable low COF stems from effective suppression of sliding-induced surface roughening and formation of delaminating tribolayer, owing to the stable gradient nanostructures that can accommodate large plastic strains under repeated sliding for more than 30,000 cycles.

UMTRA Project water sampling and analysis plan, Belfield and Bowman, North Dakota

International Nuclear Information System (INIS)

1994-08-01

Surface remedial action is scheduled to begin at the Belfield and Bowman Uranium Mill Tailings Remedial Action (UMTRA) Project sites in the spring of 1996. Water sampling was conducted in 1993 at both the Belfield processing site and the Bowman processing/disposal site. Results of the sampling at both sites indicate that ground water conditions have remained relatively stable over time. Water sampling activities are not scheduled for 1994 because ground water conditions at the two sites are relatively stable, the 1993 sampling was comprehensive, and surface remediation activities are not scheduled to start until 1996. The next water sampling event is scheduled before the start of remedial activities and will include sampling selected monitor wells at both sites and several domestic wells in the vicinity

Trends and problems on the studies by stable isotope ratio mass spectrometry for verifying the geographical origin of foods

International Nuclear Information System (INIS)

Korenaga, Takashi

2013-01-01

The multi-stable isotopic analysis method has employed to solve food authenticity problems. Stable isotope ratio of the light elements such as H, C, N, and O in food samples (e.g., rice, beef, and eel) were precisely analyzed by elemental analysis/isotope ratio mass spectrometry. Those samples were mainly taken from four different countries; Japan, United States of America, Australia, and China as comparison. All the rice samples were grown in the presence of either natural and or artificial fertilizer. The beef samples were taken from three different countries; Japan, United States of America, and Australia. Imported beef samples were also presented from the Ministry of Agriculture, Forestry and Fisheries, Japan, and compared with a correlation equation. The eel samples were taken from the three different countries and areas; Japan, China, and Taiwan. δX values showing some differences, all the Japanese food samples were clearly distinctive from the United States of America, Australia, China, and Taiwan samples. The results may be explained by the regional differences in isotope signatures of the climate, utilized nutrition, and/or quality of irrigation water among the farming countries. The statistical distinction could be one of the useful metrics to extract the food samples (rice, meat, fish, etc.) grown in Japan from those grown in the other countries. The dynamics analysis studies on stable isotopic behavior (i.e., Isotopomics) in human metabolism may be looking forward to establish a new science in near future. (author)

Addiction treatment and stable housing among a cohort of injection drug users.

Directory of Open Access Journals (Sweden)

Anita Palepu

Full Text Available Unstable housing and homelessness is prevalent among injection drug users (IDU. We sought to examine whether accessing addiction treatment was associated with attaining stable housing in a prospective cohort of IDU in Vancouver, Canada.We used data collected via the Vancouver Injection Drug User Study (VIDUS between December 2005 and April 2010. Attaining stable housing was defined as two consecutive "stable housing" designations (i.e., living in an apartment or house during the follow-up period. We assessed exposure to addiction treatment in the interview prior to the attainment of stable housing among participants who were homeless or living in single room occupancy (SRO hotels at baseline. Bivariate and multivariate associations between the baseline and time-updated characteristics and attaining stable housing were examined using Cox proportional hazard regression models.Of the 992 IDU eligible for this analysis, 495 (49.9% reported being homeless, 497 (50.1% resided in SRO hotels, and 380 (38.3% were enrolled in addiction treatment at the baseline interview. Only 211 (21.3% attained stable housing during the follow-up period and of this group, 69 (32.7% had addiction treatment exposure prior to achieving stable housing. Addiction treatment was inversely associated with attaining stable housing in a multivariate model (adjusted hazard ratio [AHR]=0.71; 95% CI: 0.52-0.96. Being in a partnered relationship was positively associated with the primary outcome (AHR=1.39; 95% CI: 1.02-1.88. Receipt of income assistance (AHR=0.65; 95% CI: 0.44-0.96, daily crack use (AHR=0.69; 95% CI: 0.51-0.93 and daily heroin use (AHR=0.63; 95% CI: 0.43-0.92 were negatively associated with attaining stable housing.Exposure to addiction treatment in our study was negatively associated with attaining stable housing and may have represented a marker of instability among this sample of IDU. Efforts to stably house this vulnerable group may be occurring in contexts

Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography–mass spectrometry and stable labeled isotope as internal standard

Energy Technology Data Exchange (ETDEWEB)

Varlet, V., E-mail: vincent.varlet@chuv.ch [Toxicology and Forensic Chemistry Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland); Smith, F. [Toxicology and Forensic Chemistry Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland); Froidmont, S. de; Dominguez, A.; Rinaldi, A. [Forensic Medicine Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland); Augsburger, M. [Toxicology and Forensic Chemistry Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland); Mangin, P.; Grabherr, S. [Forensic Medicine Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland)

2013-06-19

Graphical abstract: -- Highlights: •We developed a method for CO{sub 2} analysis in cardiac samples and quantification by {sup 13}CO{sub 2}. •This method was fully validated by accuracy profile. •We have applied this method to perform CO{sub 2} precise quantification for forensic applications. •Context of the death could be documented following CO{sub 2} concentrations. -- Abstract: A novel approach to measure carbon dioxide (CO{sub 2}) in gaseous samples, based on a precise and accurate quantification by {sup 13}CO{sub 2} internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography–mass spectrometry (HS-GC–MS) method applicable in the routine determination of CO{sub 2}. The main drawback of the GC methods discussed in the literature for CO{sub 2} measurement is the lack of a specific internal standard necessary to perform quantification. CO{sub 2} measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ({sup 13}CO{sub 2}) on the basis of the stoichiometric formation of CO{sub 2} by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH{sup 13}CO{sub 3}). This method allows a precise measurement of CO{sub 2} concentration and was validated on various human postmortem gas samples in order to study its efficiency.

Patterns in Stable Isotope Values of Nitrogen and Carbon in ...

Science.gov (United States)

Stable isotope measurements of nitrogen and carbon (15N, 13ddC) are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step toward developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter 15dN values ranged from 0.8 to 17.4‰, and 13dC values from −26.4 to −15.6‰over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends toward lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher 15dN and 13dC values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the 15dN of subsurface and surface particulate m

The effect of environmental factors on stable isotopic composition of n-alkanes in Mediterranean olive oils

Science.gov (United States)

Pedentchouk, Nikolai; Mihailova, Alina; Abbado, Dimitri

2014-05-01

Traceability of the geographic origin of olive oils is an important issue from both commercial and health perspectives. This study evaluates the impact of environmental factors on stable C and H isotope compositions of n-alkanes in extra virgin olive oils from Croatia, France, Greece, Italy, Morocco, Portugal, Slovenia, and Spain. The data are used to investigate the applicability of stable isotope methodology for olive oil regional classification in the Mediterranean region. Analysis of stable C isotope composition of n-C29 alkane showed that extra virgin olive oils from Portugal and Spain have the most positive n-C29 alkane delta13C values. Conversely, olive oils from Slovenia, northern and central Italy are characterized by the most negative values. Overall, the n-C29 alkane delta13C values show a positive correlation with the mean air temperature during August-December and a negative correlation with the mean relative humidity during these months. Analysis of stable H isotope composition of n-C29 alkane revealed that the deltaD values are the most positive in olive oils from Greece and Morocco and the most negative in oils from northern Italy. The deltaD values of oils show significant correlation with all the analyses geographical parameters: the mean air temperature and relative humidity during August-December, the total amount of rainfall (the same months) and the annual deltaD values of precipitation. As predictor variables in the Categorical Data Analysis, the n-C29 alkane deltaD values show the most significant discriminative power, followed by the n-C29 alkane delta13C values. Overall, 93.4% of olive oil samples have been classified correctly into one of the production regions. Our findings suggest that an integrated analysis of C and H isotope compositions of n-alkanes extracted from extra virgin olive oil could become a useful tool for geographical provenancing of this highly popular food commodity.

Structure of acid-stable carmine.

Science.gov (United States)

Sugimoto, Naoki; Kawasaki, Yoko; Sato, Kyoko; Aoki, Hiromitsu; Ichi, Takahito; Koda, Takatoshi; Yamazaki, Takeshi; Maitani, Tamio

2002-02-01

Acid-stable carmine has recently been distributed in the U.S. market because of its good acid stability, but it is not permitted in Japan. We analyzed and determined the structure of the major pigment in acid-stable carmine, in order to establish an analytical method for it. Carminic acid was transformed into a different type of pigment, named acid-stable carmine, through amination when heated in ammonia solution. The features of the structure were clarified using a model compound, purpurin, in which the orientation of hydroxyl groups on the A ring of the anthraquinone skeleton is the same as that of carminic acid. By spectroscopic means and the synthesis of acid-stable carmine and purpurin derivatives, the structure of the major pigment in acid-stable carmine was established as 4-aminocarminic acid, a novel compound.

Applications of stable isotopes

International Nuclear Information System (INIS)

Letolle, R.; Mariotti, A.; Bariac, T.

1991-06-01

This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

Daily cortisol production rate in man determined by stable isotope dilution/mass spectrometry

International Nuclear Information System (INIS)

Esteban, N.V.; Loughlin, T.; Yergey, A.L.; Zawadzki, J.K.; Booth, J.D.; Winterer, J.C.; Loriaux, D.L.

1991-01-01

Growth retardation as well as the development of Cushingoid features in adrenally insufficient patients treated with the currently accepted replacement dose of cortisol (33-41 mumol/day.m2; 12-15 mg/m2.day) prompted us to reevaluate the cortisol production rate (FPR) in normal subjects and patients with Cushing's syndrome, using a recently developed thermospray liquid chromatography-mass spectrometry method. The stable isotope [9,12,12-2H3]cortisol was infused continuously for 31 h at about 5% of the anticipated FPR. Blood samples were obtained at 20-min intervals for 24 h, spun, and pooled in 4-h groups. Tracer dilution in plasma was determined by liquid chromatography/mass spectrometry. The method was validated with controlled infusions in 6 patients with adrenal insufficiency. Results from 12 normal volunteers revealed a FPR of 27.3 +/- 7.5 mumol/day (9.9 +/- 2.7 mg/day) or 15.7 mumol/day.m2; 5.7 mg/m2. day. A previously unreported circadian variation in FPR was observed. Patients with Cushing's syndrome demonstrated unequivocal elevation of FPR and cortisol concentration correlated during each sample period in normal volunteers, indicating that cortisol secretion, rather than metabolism, is mainly responsible for changes in plasma cortisol. Our data suggest that the FPR in normal subjects may be lower than previously believed

Inferring the source of evaporated waters using stable H and O isotopes

Science.gov (United States)

Stable isotope ratios of H and O are widely used to identify the source of water, e.g., in aquifers, river runoff, soils, plant xylem, and plant-based beverages. In situations where the sampled water is partially evaporated, its isotope values will have evolved along an evaporati...

A guide for the laboratory information management system (LIMS) for light stable isotopes--Versions 7 and 8

Science.gov (United States)

Coplen, Tyler B.

2000-01-01

The reliability and accuracy of isotopic data can be improved by utilizing database software to (i) store information about samples, (ii) store the results of mass spectrometric isotope-ratio analyses of samples, (iii) calculate analytical results using standardized algorithms stored in a database, (iv) normalize stable isotopic data to international scales using isotopic reference materials, and (v) generate multi-sheet paper templates for convenient sample loading of automated mass-spectrometer sample preparation manifolds. Such a database program, the Laboratory Information Management System (LIMS) for Light Stable Isotopes, is presented herein. Major benefits of this system include (i) a dramatic improvement in quality assurance, (ii) an increase in laboratory efficiency, (iii) a reduction in workload due to the elimination or reduction of retyping of data by laboratory personnel, and (iv) a decrease in errors in data reported to sample submitters. Such a database provides a complete record of when and how often laboratory reference materials have been analyzed and provides a record of what correction factors have been used through time. It provides an audit trail for laboratories. LIMS for Light Stable Isotopes is available for both Microsoft Office 97 Professional and Microsoft Office 2000 Professional as versions 7 and 8, respectively. Both source code (mdb file) and precompiled executable files (mde) are available. Numerous improvements have been made for continuous flow isotopic analysis in this version (specifically 7.13 for Microsoft Access 97 and 8.13 for Microsoft Access 2000). It is much easier to import isotopic results from Finnigan ISODAT worksheets, even worksheets on which corrections for amount of sample (linearity corrections) have been added. The capability to determine blank corrections using isotope mass balance from analyses of elemental analyzer samples has been added. It is now possible to calculate and apply drift corrections to isotopic

Assessment of trace elements, POPs, 210Po and stable isotopes (15N and 13C) in a rare filter-feeding shark: The megamouth

International Nuclear Information System (INIS)

Moura, Jailson Fulgencio de; Merico, Agostino; Montone, Rosalinda Carmela; Silva, Josilene; Seixas, Tércia Guedes; Godoy, José Marcus de Oliveira; Saint’Pierre, Tatiana Dillenburg; Hauser-Davis, Rachel Ann

2015-01-01

Highlights: • Pollutants were analyzed in a megamouth shark found stranded in Brazilian coast. • Stable isotopes analyzes revealed a pelagic and filter-feeding habits of the shark. • Low levels of pollutants seem to be linked with the trophic ecology of the species. - Abstract: With less than 60 records being reported worldwide, the megamouth (Megachasma pelagios) is today one of the least known shark species inhabiting our oceans. Therefore, information concerning the biology and ecology of this enigmatic organism is very scarce and limited to feeding behaviour and preferred habitat. The present work reports new data on the concentrations of trace elements, organic mercury, POPs and 210 Po in hepatic and muscular tissues of a specimen found stranded in the southeastern coast of Brazil. Additionally, we provide new evidence based on stable isotope analysis (δ 15 N and δ 13 C) confirming the preference for the pelagic habitat and the zooplanktivorous feeding behaviour of the megamouth. These results are consistent with the low concentrations of organic pollutant compounds and other elements measured in our samples

Final report on fourth interlaboratory comparison exercise for δ2H and δ18O analysis of water samples (WICO2011)

International Nuclear Information System (INIS)

Ahmad, M.; Aggarwal, P.; Duren, M. van; Poltenstein, L.; Araguas, L.; Kurttas, T.; Wassenaar, L.I.

2012-01-01

The IAEA Isotope Hydrology Laboratory organized the fourth interlaboratory comparison exercise for laboratories engaged in routine analysis of hydrogen and oxygen stable isotope composition of water samples in 2011. Three similar exercises were carried out in 1995, in 1999 and in 2002. However, the tradition of IAEA water stable isotope inter-laboratory comparison is much older. Two interlaboratory comparison trials for isotope hydrology laboratories were carried out in the sixties and seventies, which revealed problems with use of the NBS-1 international standard; these data were used to calibrate the newly produced primary reference materials VSMOW and SLAP. The WICO2011 exercise was announced in February 2011 on the internet, via the ISOGEOCHEM news group of Isogeochemistry and by email to all participants of the former intercomparisons. Altogether 174 laboratories expressed interest to participate in the exercise. Four water samples prepared and calibrated at the IAEA Isotope Hydrology Laboratory were labelled IAEA-OH-13 to IAEA-OH-16, which are referred to in this report as OH-13 to OH-16. By the end of the reporting deadline (the end of August 2011) altogether 137 laboratories from 53 countries had submitted 172 datasets back to the IAEA on the oxygen and hydrogen isotopic composition of these water samples. The four water samples cover the range of δ18O and δ2H values typical for the majority of natural waters. The samples were bottled from 30 L stainless steel storage barrels into 30 mL securely-capped brown glass bottles, serially numbered at the time of filling. Each laboratory received a set of four samples with a corresponding code. This code (assigned randomly) forms the Identification (ID) code used throughout the exercise and in the tables and graphs of this report for each laboratory. The ID code is not related to the order of the list of participating laboratories. The identity of participating laboratories will not be revealed unless each

Methane hydrate distribution from prolonged and repeated formation in natural and compacted sand samples: X-ray CT observations

Energy Technology Data Exchange (ETDEWEB)

Rees, E.V.L.; Kneafsey, T.J.; Seol, Y.

2010-07-01

To study physical properties of methane gas hydrate-bearing sediments, it is necessary to synthesize laboratory samples due to the limited availability of cores from natural deposits. X-ray computed tomography (CT) and other observations have shown gas hydrate to occur in a number of morphologies over a variety of sediment types. To aid in understanding formation and growth patterns of hydrate in sediments, methane hydrate was repeatedly formed in laboratory-packed sand samples and in a natural sediment core from the Mount Elbert Stratigraphic Test Well. CT scanning was performed during hydrate formation and decomposition steps, and periodically while the hydrate samples remained under stable conditions for up to 60 days. The investigation revealed the impact of water saturation on location and morphology of hydrate in both laboratory and natural sediments during repeated hydrate formations. Significant redistribution of hydrate and water in the samples was observed over both the short and long term.

Validation of ICD-9 Codes for Stable Miscarriage in the Emergency Department.

Science.gov (United States)

Quinley, Kelly E; Falck, Ailsa; Kallan, Michael J; Datner, Elizabeth M; Carr, Brendan G; Schreiber, Courtney A

2015-07-01

International Classification of Disease, Ninth Revision (ICD-9) diagnosis codes have not been validated for identifying cases of missed abortion where a pregnancy is no longer viable but the cervical os remains closed. Our goal was to assess whether ICD-9 code "632" for missed abortion has high sensitivity and positive predictive value (PPV) in identifying patients in the emergency department (ED) with cases of stable early pregnancy failure (EPF). We studied females ages 13-50 years presenting to the ED of an urban academic medical center. We approached our analysis from two perspectives, evaluating both the sensitivity and PPV of ICD-9 code "632" in identifying patients with stable EPF. All patients with chief complaints "pregnant and bleeding" or "pregnant and cramping" over a 12-month period were identified. We randomly reviewed two months of patient visits and calculated the sensitivity of ICD-9 code "632" for true cases of stable miscarriage. To establish the PPV of ICD-9 code "632" for capturing missed abortions, we identified patients whose visits from the same time period were assigned ICD-9 code "632," and identified those with actual cases of stable EPF. We reviewed 310 patient records (17.6% of 1,762 sampled). Thirteen of 31 patient records assigned ICD-9 code for missed abortion correctly identified cases of stable EPF (sensitivity=41.9%), and 140 of the 142 patients without EPF were not assigned the ICD-9 code "632"(specificity=98.6%). Of the 52 eligible patients identified by ICD-9 code "632," 39 cases met the criteria for stable EPF (PPV=75.0%). ICD-9 code "632" has low sensitivity for identifying stable EPF, but its high specificity and moderately high PPV are valuable for studying cases of stable EPF in epidemiologic studies using administrative data.

Advances in stable isotope assisted labeling strategies with information science.

Science.gov (United States)

Kigawa, Takanori

2017-08-15

Stable-isotope (SI) labeling of proteins is an essential technique to investigate their structures, interactions or dynamics by nuclear magnetic resonance (NMR) spectroscopy. The assignment of the main-chain signals, which is the fundamental first step in these analyses, is usually achieved by a sequential assignment method based on triple resonance experiments. Independently of the triple resonance experiment-based sequential assignment, amino acid-selective SI labeling is beneficial for discriminating the amino acid type of each signal; therefore, it is especially useful for the signal assignment of difficult targets. Various combinatorial selective labeling schemes have been developed as more sophisticated labeling strategies. In these strategies, amino acids are represented by combinations of SI labeled samples, rather than simply assigning one amino acid to one SI labeled sample as in the case of conventional amino acid-selective labeling. These strategies have proven to be useful for NMR analyses of difficult proteins, such as those in large complex systems, in living cells, attached or integrated into membranes, or with poor solubility. In this review, recent advances in stable isotope assisted labeling strategies will be discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

Chemistry of Stable Carbenes and «Green» Technologies

Directory of Open Access Journals (Sweden)

Korotkikh, N.I.

2015-11-01

Full Text Available Brief analysis of fundamental research in the chemistry of stable carbenes and applications in the field of «green» chemistry on their basis carried out at the L.M. Litvinenko Institute of Physical Organic & Coal Chemistry of NAS of Ukraine over the last decade is given. Carbene versions of ester Claisen condensation to form zwitterionic compounds, the Leuckart-Wallach reaction with the autoreduction of carbenoid azolium salts, Hofmann cleavage of aminocarbene insertion products, an induced tandem autotransformation of 1,2,4-triazol-5-ylidenes into 5-amidino-1,2,4-triazoles were found. New carbene reactions of ad dition, deesterification, oxidation and complexation were revealed. Effective methods of obtaining stable carbenes and carbenoids were suggested. New types of carbenes, namely benzimidazolylidenes, superstable conjugated biscarbenes and new types of carbenoids were synthesized. The existence of hypernucleophilic carbenes was theoretically predicted and experimentally confirmed. The prospects of the use of carbenes and their derivatives, in particular, carbene complexes of transition metals in catalysis of organic reactions and the search of biologically active compounds were shown.

Application of stable isotopes to hydrogeology in coal mine

International Nuclear Information System (INIS)

Duan Qi; Duan Yucheng

1988-01-01

Stable isotopes including Oxygen-18 and Deuterium have been applied to investigation of hydrogeology in main coal mines. By determination of stable isotopic composition of hydrogen and oxygen together with water analysis, the following studies have been developed: Identification of the hydrogeochemical characteristics of the groundwater from varied aquifers; Analysis of the hydraulic relationship between varied aquifers; Interpretation of the probable recharge source of mine water. The research results mentioned above reveal that: 1. The groundwater from main aquifers at coal mines in north China is of meteoric origin, which is recharged from hilly area surrounding the coal mine. Its isotopic composition differs slightly from that of the local precipitation. 2. There is a mutual hydraulic relationship between the Ordovician and Quarternary aquifers, so the difference of isotopic composition is very small. 3. By way of the variation of isotopic composition of groundwater from coal-bearing strata, we can infer the hydraulic relationship extent between overlaid alluvial layer and underlaid Ordovician limestone. (author). 9 refs, 6 figs, 8 tabs

Analytical pyrolysis and stable isotope analyses reveal past environmental changes in coralloid speleothems from Easter Island (Chile).

Science.gov (United States)

Miller, Ana Z; De la Rosa, José M; Jiménez-Morillo, Nicasio T; Pereira, Manuel F C; González-Pérez, José A; Calaforra, José M; Saiz-Jimenez, Cesareo

2016-08-26

This study comprises an innovative approach based on the combination of chromatography (analytical pyrolysis and pyrolysis compound-specific isotope analysis (Py-CSIA)), light stable isotopes, microscopy and mineralogy analyses to characterize the internal layering of coralloid speleothems from the Ana Heva lava tube in Easter Island (Chile). This multidisciplinary proxy showed that the speleothems consist of banded siliceous materials of low crystallinity with different mineralogical compositions and a significant contribution of organic carbon. Opal-A constitutes the outermost grey layer of the coralloids, whereas calcite and amorphous Mg hydrate silicate are the major components of the inner whitish and honey-brown layers, respectively. The differences found in the mineralogical, elemental, molecular and isotopic composition of these distinct coloured layers are related to environmental changes during speleothem development. Stable isotopes and analytical pyrolysis suggested alterations in the water regime, pointing to wetter conditions during the formation of the Ca-rich layer and a possible increase in the amount of water dripping into the cave. The trend observed for δ(15)N values suggested an increase in the average temperature over time, which is consistent with the so-called climate warming during the Holocene. The pyrolysis compound-specific isotope analysis of each speleothem layer showed a similar trend with the bulk δ(13)C values pointing to the appropriateness of direct Py-CSIA in paleoenvironmental studies. The δ(13)C values for n-alkanes reinforced the occurrence of a drastic environmental change, indicating that the outermost Opal layer was developed under drier and more arid environmental conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Trends in the use of stable isotopes in biochemistry and pharmacology

International Nuclear Information System (INIS)

Matwiyoff, N.A.; Walker, T.E.

1977-01-01

Recent trends in the use of the stable isotopes 13 C, 15 N and 18 O in biochemistry and pharmacology are reviewed with emphasis on the studies that have employed nuclear magnetic resonance (nmr) spectroscopy and mass spectrometry as analytical techniques. Pharmacological studies with drugs and other compounds labelled with stable isotopes have developed in parallel with the rapid progress in the enhancement of sensitivity and selectivity of gas chromatography - mass spectrometric analyses, and have been directed largely to an evaluation of pharmako-kinetics and drug metabolic pathways. In these studies, illustrated with selected samples, isotopically labelled compounds have been used to advantage as internal standards for the mass spectrometric analyses and as in vivo tracers for metabolites. In the broader discipline of biochemistry, stable isotopes and isotopically labelled compounds have been used increasingly in conjuction with both nmr spectroscopy and mass spectrometry in tracer and structural studies. The more recent trends in the use of stable isotopes in these biochemical studies are discussed in the context of the improvements in analytical techniques. Specific examples will be drawn from investigations of the biosynthesis of natural products by micro-organisms; the protein, fat and carbohydrate fluxes in humans; and the structure and function of enzymes, membranes and other macro-molecular assemblages. The potential for the future development of stable isotopes in biochemistry and pharmacology are considered briefly, together with some of the problems that must be solved if their considerable potential is to be realized. (author)

Investigating the Relationship between Stable Personality Characteristics and Automatic Imitation

OpenAIRE

Butler, Emily E.; Ward, Robert; Ramsey, Richard

2015-01-01

Automatic imitation is a cornerstone of nonverbal communication that fosters rapport between interaction partners. Recent research has suggested that stable dimensions of personality are antecedents to automatic imitation, but the empirical evidence linking imitation with personality traits is restricted to a few studies with modest sample sizes. Additionally, atypical imitation has been documented in autism spectrum disorders and schizophrenia, but the mechanisms underpinning these behaviour...

Limiting stable states of high-Tc superconductors in the alternating current modes

International Nuclear Information System (INIS)

Romanovskii, V.R.; Watanabe, K.; Awaji, S.

2014-01-01

The limiting current-carrying capacity of high-T c superconductor and superconducting tape has been studied in the alternating current states. The features that are responsible for their stable formation have been investigated under the conduction-cooled conditions when the operating peak values of the electric field and the current may essentially exceed the corresponding critical values of superconductor. Besides, it has been proved that these peak values are higher than the values of the electric field and the current, which lead to the thermal runaway phenomenon when the current instability onset occurs in the operating modes with direct current. As a result, the stable extremely high heat generation exists in these operating states, which can be called as overloaded states. The limiting stable peak values of charged currents and stability conditions have been determined taking into account the flux creep states of superconductors. The analysis performed has revealed that there exist characteristic times defining the corresponding time windows in the stable development of overloaded states of the alternating current. In order to explain their existence, the basic thermo-electrodynamics mechanisms have been formulated, which have allowed to explain the high stable values of the temperature and the induced electric field before the onset of alternating current instability. In general, it has been shown that the high-T c superconductors may stably operate in the overloaded alternating current states even under the not intensive cooling conditions at a very high level of heat generation, which is not considered in the existing theory of losses. (authors)

Molecular and stable carbon isotopic characterization of PAH contaminants at McMurdo Station, Antarctica

International Nuclear Information System (INIS)

Kim, Moonkoo . E-mail moonkoo.kim@wmich.edu; Kennicutt, Mahlon C.; Qian Yaorong

2006-01-01

The molecular and stable carbon isotopic compositions of contaminant polycyclic aromatic hydrocarbons (PAHs) at McMurdo Station, Antarctica were analyzed in samples collected from land and sub-tidal area. PAHs in the study areas were characterized by high amounts of naphthalene and alkylated naphthalenes from petroleum products introduced by human activities in the area. Principal component analysis (PCA) of PAH composition data identified multiple sources of PAH contamination in the study area. Compositional assignments of origins were confirmed using compound specific stable carbon isotopic analysis

Osteoprotegerin independently predicts mortality in patients with stable coronary artery disease: the CLARICOR trial

DEFF Research Database (Denmark)

Bjerre, Mette; Hilden, Jørgen; Kastrup, Jens

2014-01-01

OBJECTIVES: To elucidate the prognostic power of serum osteoprotegerin (OPG) in patients with stable coronary artery disease (CAD). METHODS: Serum OPG levels were measured in the CLARICOR trial cohort of 4063 patients with stable CAD on blood samples drawn at randomization. The follow-up was 2...... predictor for all-cause mortality. Importantly, OPG remained an independent predictor of mortality even after adjustment for both clinical and conventional cardiovascular risk markers (HR 2.5 [95% CI 1.6-3.9, p power as to all...

What climate information is recorded in stable isotope ratios of wood lignin methoxyl groups?

Science.gov (United States)

Greule, Markus; Keppler, Frank

2010-05-01

The stable isotope composition of the bioelements C, O, H and N in plant organic matter is known to be a very powerful for various environmental impacts. Particularly tree rings are suitable for this analysis because they exhibit a "climate archive" with a yearly or even biannual resolution. One of the most determined wood compounds is cellulose which amongst others is used to reconstruct the temperature due to measurement of stable hydrogen and oxygen isotopes. Therefore cellulose is converted into cellulose nitrate to eliminate the exchangeable hydroxyl hydrogen or equilibration methods are used. However, a general problem associated with the determination of the stable hydrogen values of marker compounds for the study of climate and environmental conditions is the isolation of the pure compound for analysis by isotope ratio mass spectrometry. Exploitation of components of wood as markers, in particular, has been restricted by the very labour intensive and time consuming preparation of samples (e.g. cellulose nitrate). An alternative way to record climate information from tree rings was recently proposed by Keppler et al. (2007) who measured the stable hydrogen values of methoxyl groups in wood. Lignin methoxyl groups are considered to be stable, i.e. the hydrogen atoms of the methoxyl moiety do not exchange with those of plant water during ongoing metabolic reactions in the plant. Thus the initial deuterium content of the methoxyl groups of lignin in woody tissue at formation is retained throughout the lifetime of the tree and in preserved tissue. The methoxyl content of lignin in wood is usually determined by the Zeisel method (Zeisel, 1885) - the reaction between methyl ethers and hydroiodic acid to form methyl iodide. Exploiting this reaction for the measurement of stable hydrogen values of lignin methoxyl groups ensures that during the entire analytical procedure the isotope signal is preserved since no isotopic exchange occurs between the methyl groups and

Stable and dynamic microtubules coordinately shape the myosin activation zone during cytokinetic furrow formation

Science.gov (United States)

Foe, Victoria E.; von Dassow, George

2008-01-01

The cytokinetic furrow arises from spatial and temporal regulation of cortical contractility. To test the role microtubules play in furrow specification, we studied myosin II activation in echinoderm zygotes by assessing serine19-phosphorylated regulatory light chain (pRLC) localization after precisely timed drug treatments. Cortical pRLC was globally depressed before cytokinesis, then elevated only at the equator. We implicated cell cycle biochemistry (not microtubules) in pRLC depression, and differential microtubule stability in localizing the subsequent myosin activation. With no microtubules, pRLC accumulation occurred globally instead of equatorially, and loss of just dynamic microtubules increased equatorial pRLC recruitment. Nocodazole treatment revealed a population of stable astral microtubules that formed during anaphase; among these, those aimed toward the equator grew longer, and their tips coincided with cortical pRLC accumulation. Shrinking the mitotic apparatus with colchicine revealed pRLC suppression near dynamic microtubule arrays. We conclude that opposite effects of stable versus dynamic microtubules focuses myosin activation to the cell equator during cytokinesis. PMID:18955555

Reconstruction of trophic pathways between plankton and the North Iberian sardine (Sardina pilchardus using stable isotopes

Directory of Open Access Journals (Sweden)

Antonio Bode

2004-03-01

Full Text Available Feeding on phyto- and zooplankton by juvenile (< 1 year old and adult sardines (Sardina pilchardus was inferred from analyses of natural abundance of stable carbon and nitrogen isotopes in samples from the northwestern Iberian Peninsula (Spain collected at the beginning of the upwelling season and peak spawning period of sardine. Plankton samples were fractionated through nets of 20, 200, 500, 1000 and 2000 ?m mesh-size and the muscle protein of individual sardines was isolated before isotopic determinations. Up to six planktonic components and two sardine feeding types were identified from the modes in the frequency distributions of isotope abundance values. Also, the most probable pathways for carbon and nitrogen flows between compartments were analysed. The resulting food web revealed a relatively large degree of omnivory, both in plankton and sardine components, which confirms that complex trophic interactions could also occur in pelagic upwelling ecosystems. Young sardines had isotope abundance values clustered around a single mode in the frequency distribution, while adult sardines displayed two main modes. These modes are interpreted as representative of two extreme feeding types: one related to the individual capture of zooplankton prey and the other to unselective filter-feeding. Although both types of feeding could include micro- (20-200 ?m and mesozooplankton (200-2000 ?m prey, phytoplankton appears to be ingested mainly by filter-feeding. However, even adult sardines must be mainly zoophagous to achieve the observed isotopic abundance values, taking into account current assumptions on stable isotope enrichment through trophic levels. From the differences in the resulting pathways using either carbon or nitrogen isotopes, we interpreted that sardines acquire most of the protein nitrogen from zooplankton while a substantial fraction of their carbon would derive from phytoplankton. These interpretations agree with the information

Sampling density for the quantitative evaluation of air trapping

International Nuclear Information System (INIS)

Goris, Michael L.; Robinson, Terry E.

2009-01-01

Concerns have been expressed recently about the radiation burden on patient populations, especially children, undergoing serial radiological testing. To reduce the dose one can change the CT acquisition settings or decrease the sampling density. In this study we determined the minimum desirable sampling density to ascertain the degree of air trapping in children with cystic fibrosis. Ten children with cystic fibrosis in stable condition underwent a volumetric spiral CT scan. The degree of air trapping was determined by an automated algorithm for all slices in the volume, and then for 1/2, 1/4, to 1/128 of all slices, or a sampling density ranging from 100% to 1% of the total volume. The variation around the true value derived from 100% sampling was determined for all other sampling densities. The precision of the measurement remained stable down to a 10% sampling density, but decreased markedly below 3.4%. For a disease marker with the regional variability of air trapping in cystic fibrosis, regardless of observer variability, a sampling density below 10% and even more so, below 3.4%, apparently decreases the precision of the evaluation. (orig.)

Optimization of protein samples for NMR using thermal shift assays

International Nuclear Information System (INIS)

Kozak, Sandra; Lercher, Lukas; Karanth, Megha N.; Meijers, Rob; Carlomagno, Teresa; Boivin, Stephane

2016-01-01

Maintaining a stable fold for recombinant proteins is challenging, especially when working with highly purified and concentrated samples at temperatures >20 °C. Therefore, it is worthwhile to screen for different buffer components that can stabilize protein samples. Thermal shift assays or ThermoFluor"® provide a high-throughput screening method to assess the thermal stability of a sample under several conditions simultaneously. Here, we describe a thermal shift assay that is designed to optimize conditions for nuclear magnetic resonance studies, which typically require stable samples at high concentration and ambient (or higher) temperature. We demonstrate that for two challenging proteins, the multicomponent screen helped to identify ingredients that increased protein stability, leading to clear improvements in the quality of the spectra. Thermal shift assays provide an economic and time-efficient method to find optimal conditions for NMR structural studies.

Optimization of protein samples for NMR using thermal shift assays

Energy Technology Data Exchange (ETDEWEB)

Kozak, Sandra [European Molecular Biology Laboratory (EMBL), Hamburg Outstation, SPC Facility (Germany); Lercher, Lukas; Karanth, Megha N. [European Molecular Biology Laboratory (EMBL), SCB Unit (Germany); Meijers, Rob [European Molecular Biology Laboratory (EMBL), Hamburg Outstation, SPC Facility (Germany); Carlomagno, Teresa, E-mail: teresa.carlomagno@oci.uni-hannover.de [European Molecular Biology Laboratory (EMBL), SCB Unit (Germany); Boivin, Stephane, E-mail: sboivin77@hotmail.com, E-mail: s.boivin@embl-hamburg.de [European Molecular Biology Laboratory (EMBL), Hamburg Outstation, SPC Facility (Germany)

2016-04-15

Maintaining a stable fold for recombinant proteins is challenging, especially when working with highly purified and concentrated samples at temperatures >20 °C. Therefore, it is worthwhile to screen for different buffer components that can stabilize protein samples. Thermal shift assays or ThermoFluor{sup ®} provide a high-throughput screening method to assess the thermal stability of a sample under several conditions simultaneously. Here, we describe a thermal shift assay that is designed to optimize conditions for nuclear magnetic resonance studies, which typically require stable samples at high concentration and ambient (or higher) temperature. We demonstrate that for two challenging proteins, the multicomponent screen helped to identify ingredients that increased protein stability, leading to clear improvements in the quality of the spectra. Thermal shift assays provide an economic and time-efficient method to find optimal conditions for NMR structural studies.

Population Games, Stable Games, and Passivity

Directory of Open Access Journals (Sweden)

Michael J. Fox

2013-10-01

Full Text Available The class of “stable games”, introduced by Hofbauer and Sandholm in 2009, has the attractive property of admitting global convergence to equilibria under many evolutionary dynamics. We show that stable games can be identified as a special case of the feedback-system-theoretic notion of a “passive” dynamical system. Motivated by this observation, we develop a notion of passivity for evolutionary dynamics that complements the definition of the class of stable games. Since interconnections of passive dynamical systems exhibit stable behavior, we can make conclusions about passive evolutionary dynamics coupled with stable games. We show how established evolutionary dynamics qualify as passive dynamical systems. Moreover, we exploit the flexibility of the definition of passive dynamical systems to analyze generalizations of stable games and evolutionary dynamics that include forecasting heuristics as well as certain games with memory.

Preliminary stable isotope results from the Mohos peat bog, East-Carpathians

Science.gov (United States)

Túri, Marianna; Palcsu, László; Futó, István; Hubay, Katalin; Molnár, Mihály; Rinyu, László; Braun, Mihály

2016-04-01

This work provides preliminary results of an isotope investigation carried out on a peat core drilled in the ombrotrophic Mohos peat bog, Ciomadul Mountain, (46°8'3.60"N, 25°54'19.43"E, 1050 m.a.s.l.), East Carpathians, Romania. The Ciomadul is a single dacitic volcano with two craters: the younger Saint Ana and the older Mohos which is a peat bog, and surrounded by a number of individual lava domes as well as a narrow volcaniclastic ring plain volcano. A 10 m long peat core has been taken previously, and is available for stable oxygen and carbon isotope analysis. It is known from our previous work (Hubay et al., 2015) that it covers a period from 11.500 cal year B.P. to present. The peat bog is composed mainly of Sphagnum, which has a direct relationship with the environment, making it suitable for examine the changes in the surrounding circumstances. Isotopic analysis of the prepared cellulose from Sphagnum moss has the attribute to provide such high resolution quantitative estimates of the past climate and there is no such climate studies in this area where the past climate investigations based on oxygen isotope analysis of the Sphagnum. Oxygen and carbon stable isotope analysis were carried out on the hemicellulose samples, which were chemically prepared for 14C dating and taken from every 30 cm of the 10 m long peat core. The oxygen isotope composition of the precipitation can be revealed from the δ18O values of the prepared cellulose samples, since, while carbon isotope ratio tells more about the wet and dry periods of the past. Studying both oxygen and carbon isotope signatures, slight fluctuations can be seen during the Holocene like some of the six periods of significant climate changes can be seen in this resolution during the time periods of 9000-8000, 6000-5000, 4200-3800, 3500-2500, 1200-1000, and 600-150 cal yr B.P. Additionally, the late Pleistocene - early Holocene environmental changes can be clearly observed as Pleistocene peat samples have

Stable isotopic analysis of fossil chironomids as an approach to environmental reconstruction: state of development and future challenges

Directory of Open Access Journals (Sweden)

Oliver Heiri

2012-10-01

Full Text Available Remains of chironomid larvae, especially their strongly sclerotized head capsules, can be found abundantly and well preserved in most lake sediment records. These remains mainly consist of chitin and proteins and, since their chemical composition does not seem to be strongly affected by decompositional processes, they can be used to develop palaeoenvironmental reconstructions based on their stable isotopic composition. Here we review available stable isotope studies based on fossil chironomids and indicate future research necessary to further develop this still relatively new research approach. Efforts to produce stable isotope records based on fossil chironomids have mainly examined the elements H, N, C, and O. They have focussed on (1 developing the methodology for preparing samples for isotopic analysis, (2 laboratory studies cultivating chironomid larvae under controlled conditions to determine the factors affecting their stable isotopic composition, (3 ecosystem-scale studies relating stable isotopic measurements of fossil chironomid assemblages to environmental conditions, and (4 developing first down-core records describing past changes in the stable isotopic composition of chironomid assemblages. These studies have shown that chemical sample pretreatment may affect the isotopic composition for some elements. Laboratory runs suggest that the diet of the larvae influences their stable isotopic composition for H, N, C and O, whereas stable isotopes in the ambient water also strongly influence their oxygen and to a lesser extent hydrogen isotopic composition. These experiments also indicate only minor offsets between the nitrogen and carbon isotopic composition of chironomid soft tissue and the fossilizing head capsules, whereas for hydrogen and oxygen this offset remains to be explored. Though few datasets have been published, the available ecosystem studies and developed down-core sediment records indicate that stable isotopes in

Molecularly imprinted solid phase extraction using stable isotope labeled compounds as template and liquid chromatography-mass spectrometry for trace analysis of bisphenol A in water sample

International Nuclear Information System (INIS)

Kawaguchi, Migaku; Hayatsu, Yoshio; Nakata, Hisao; Ishii, Yumiko; Ito, Rie; Saito, Koichi; Nakazawa, Hiroyuki

2005-01-01

We have developed a molecularly imprinted polymer (MIP) using a stable isotope labeled compound as the template molecule and called it the ''isotope molecularly imprinted polymer'' (IMIP). In this study, bisphenol A (BPA) was used as the model compound. None imprinted polymer (NIP), MIP, dummy molecularly imprinted polymer (DMIP) and IMIP were prepared by the suspension polymerization method using without template, BPA, 4-tert-butylphenol (BP) and bisphenol A-d 16 (BPA-d 16 ), respectively. The polymers were subjected to molecularly imprinted solid phase extraction (MI-SPE), and the extracted samples were subjected to liquid chromatography-mass spectrometry (LC-MS). Although the leakage of BPA-d 16 from the IMIP was observed and that of BPA was not observed. The selectivity factors of MIP and IMIP for BPA were 4.45 and 4.43, respectively. Therefore, IMIP had the same molecular recognition ability as MIP. When MI-SPE with IMIP was used and followed by LC-MS in the analysis of river water sample, the detection limit of BPA was 1 ppt with high sensitivity. Moreover, the average recovery was higher than 99.8% (R.S.D.: 3.7%) by using bisphenol A- 13 C 12 (BPA- 13 C 12 ) as the surrogate standard. In addition, the IMIP were employed in MI-SPE of BPA in river water sample by LC-MS. The concentration of BPA in the river water sample was determined to be 32 pg ml -1 . We confirmed that it was possible to measure trace amounts of a target analyte by MI-SPE using IMIP

Normalization Methods and Selection Strategies for Reference Materials in Stable Isotope Analyses - Review

International Nuclear Information System (INIS)

Skrzypek, G.; Sadler, R.; Paul, D.; Forizs, I.

2011-01-01

A stable isotope analyst has to make a number of important decisions regarding how to best determine the 'true' stable isotope composition of analysed samples in reference to an international scale. It has to be decided which reference materials should be used, the number of reference materials and how many repetitions of each standard is most appropriate for a desired level of precision, and what normalization procedure should be selected. In this paper we summarise what is known about propagation of uncertainties associated with normalization procedures and propagation of uncertainties associated with reference materials used as anchors for the determination of 'true' values for δ''1''3C and δ''1''8O. Normalization methods Several normalization methods transforming the 'raw' value obtained from mass spectrometers to one of the internationally recognized scales has been developed. However, as summarised by Paul et al. different normalization transforms alone may lead to inconsistencies between laboratories. The most common normalization procedures are: single-point anchoring (versus working gas and certified reference standard), modified single-point normalization, linear shift between the measured and the true isotopic composition of two certified reference standards, two-point and multipoint linear normalization methods. The accuracy of these various normalization methods has been compared by using analytical laboratory data by Paul et al., with the single-point and normalization versus tank calibrations resulting in the largest normalization errors, and that also exceed the analytical uncertainty recommended for δ 13 C. The normalization error depends greatly on the relative differences between the stable isotope composition of the reference material and the sample. On the other hand, the normalization methods using two or more certified reference standards produces a smaller normalization error, if the reference materials are bracketing the whole range of

Stable electroluminescence from passivated nano-crystalline porous silicon using undecylenic acid

Energy Technology Data Exchange (ETDEWEB)

Gelloz, B.; Sano, H.; Koshida, N. [Dept. Elec. and Elec. Eng., Tokyo Univ. of A and T, Koganei, Tokyo 184-8588 (Japan); Boukherroub, R. [Laboratoire de Physique de la Matiere Condensee, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau (France); Wayner, D.D.M.; Lockwood, D.J. [National Research Council, Ottawa (Canada)

2005-06-01

Stabilization of electroluminescence from nanocrystalline porous silicon diodes has been achieved by replacing silicon-hydrogen bonds terminating the surface of nanocrystalline silicon with more stable silicon-carbon (Si-C) bonds. Hydrosilylation of the surface of partially and anodically oxidized porous silicon samples was thermally induced at about 90 C using various different organic molecules. Devices whose surface have been modified with stable covalent bonds shows no degradation in the EL efficiency and EL output intensity under DC operation for several hours. The enhanced stability can be attributed to the high chemical resistance of Si-C bonds against current-induced surface oxidation associated with the generation of nonradiative defects. Although devices treated with 1-decene exhibit reduced EL efficiency and brightness compared to untreated devices, other molecules, such as ethyl-undecylenate and particularly undecylenic acid provide stable and more efficient visible electroluminescence at room temperature. Undecylenic acid provides EL brightness as high as that of an untreated device. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

On the development of automatic sample preparation devices

International Nuclear Information System (INIS)

Oesselmann, J.

1987-01-01

Modern mass spectrometers for stable isotope analysis offer accurate isotope ratio results from gaseous samples (CO 2 , N 2 , H 2 , SO 2 ) in a completely automated fashion. However, most samples of interest either are associated with contaminant gases or the gas has to be liberated by a chemical procedure prior to measurement. In most laboratories this sample preparation step is performed manually. As a consequence, sample throughput is rather low and - despite skilful operation - the preparation procedure varies slightly from one sample to the next affecting mainly the reproducibility of the data. (author)

Stable Lévy motion with inverse Gaussian subordinator

Science.gov (United States)

Kumar, A.; Wyłomańska, A.; Gajda, J.

2017-09-01

In this paper we study the stable Lévy motion subordinated by the so-called inverse Gaussian process. This process extends the well known normal inverse Gaussian (NIG) process introduced by Barndorff-Nielsen, which arises by subordinating ordinary Brownian motion (with drift) with inverse Gaussian process. The NIG process found many interesting applications, especially in financial data description. We discuss here the main features of the introduced subordinated process, such as distributional properties, existence of fractional order moments and asymptotic tail behavior. We show the connection of the process with continuous time random walk. Further, the governing fractional partial differential equations for the probability density function is also obtained. Moreover, we discuss the asymptotic distribution of sample mean square displacement, the main tool in detection of anomalous diffusion phenomena (Metzler et al., 2014). In order to apply the stable Lévy motion time-changed by inverse Gaussian subordinator we propose a step-by-step procedure of parameters estimation. At the end, we show how the examined process can be useful to model financial time series.

Is early-onset microsatellite and chromosomally stable colorectal cancer a hallmark of a genetic susceptibility syndrome?

Science.gov (United States)

Kets, C M; van Krieken, J H J M; van Erp, P E J; Feuth, T; Jacobs, Y H A; Brunner, H G; Ligtenberg, M J L; Hoogerbrugge, N

2008-02-15

Most colorectal cancers show either microsatellite or chromosomal instability. A subset of colorectal cancers, especially those diagnosed at young age, is known to show neither of these forms of genetic instability and thus might have a distinct pathogenesis. Colorectal cancers diagnosed at young age are suggestive for hereditary predisposition. We investigate whether such early-onset microsatellite and chromosomally stable colorectal cancers are a hallmark of a genetic susceptibility syndrome. The ploidy status of microsatellite stable (familial) colorectal cancers of patients diagnosed before age 50 (n = 127) was analyzed in relation to the histopathological characteristics and family history. As a control the ploidy status of sporadic colorectal cancer, with normal staining of mismatch repair proteins, diagnosed at the age of 69 years or above (n = 70) was determined. A diploid DNA content was used as a marker for chromosomal stability. Within the group of patients with (familial) early onset microsatellite stable colorectal cancer the chromosomally stable tumors did not differ from chromosomally unstable tumors with respect to mean age at diagnosis, fulfillment of Amsterdam criteria or pathological characteristics. Segregation analysis did not reveal any family with microsatellite and chromosomally stable colorectal cancer in 2 relatives. The prevalence of microsatellite and chromosomally stable colorectal cancer was not significantly different for the early and late onset group (28 and 21%, respectively). We find no evidence that early-onset microsatellite and chromosomally stable colorectal cancer is a hallmark of a hereditary colorectal cancer syndrome. (c) 2007 Wiley-Liss, Inc.

Sampling procedure in a willow plantation for chemical elements important for biomass combustion quality

DEFF Research Database (Denmark)

Liu, Na; Nielsen, Henrik Kofoed; Jørgensen, Uffe

2015-01-01

clone ‘Tordis’, and to reveal the relationship between sampling position, shoot diameters, and distribution of elements. Five Tordis willow shoots were cut into 10–50 cm sections from base to top. The ash content and concentration of twelve elements (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, Si, and Zn......Willow (Salix spp.) is expected to contribute significantly to the woody bioenergy system in the future, so more information on how to sample the quality of the willow biomass is needed. The objectives of this study were to investigate the spatial variation of elements within shoots of a willow......) in each section were determined. The results showed large spatial variation in the distribution of most elements along the length of the willow shoots. Concentrations of elements in 2-year old shoots of the willow clone Tordis were fairly stable within the range of 100–285 cm above ground and resembled...

Spatial-Frequency Azimuthally Stable Cartography of Biological Polycrystalline Networks

Directory of Open Access Journals (Sweden)

V. A. Ushenko

2013-01-01

Full Text Available A new azimuthally stable polarimetric technique processing microscopic images of optically anisotropic structures of biological tissues histological sections is proposed. It has been used as a generalized model of phase anisotropy definition of biological tissues by using superposition of Mueller matrices of linear birefringence and optical activity. The matrix element M44 has been chosen as the main information parameter, whose value is independent of the rotation angle of both sample and probing beam polarization plane. For the first time, the technique of concerted spatial-frequency filtration has been used in order to separate the manifestation of linear birefringence and optical activity. Thereupon, the method of azimuthally stable spatial-frequency cartography of biological tissues histological sections has been elaborated. As the analyzing tool, complex statistic, correlation, and fractal analysis of coordinate distributions of M44 element has been performed. The possibility of using the biopsy of the uterine wall tissue in order to differentiate benign (fibromyoma and malignant (adenocarcinoma conditions has been estimated.

Defining a stable water isotope framework for isotope hydrology application in a large trans-boundary watershed (Russian Federation/Ukraine).

Science.gov (United States)

Vystavna, Yuliya; Diadin, Dmytro; Huneau, Frédéric

2018-05-01

Stable isotopes of hydrogen ( 2 H) and oxygen ( 18 O) of the water molecule were used to assess the relationship between precipitation, surface water and groundwater in a large Russia/Ukraine trans-boundary river basin. Precipitation was sampled from November 2013 to February 2015, and surface water and groundwater were sampled during high and low flow in 2014. A local meteoric water line was defined for the Ukrainian part of the basin. The isotopic seasonality in precipitation was evident with depletion in heavy isotopes in November-March and an enrichment in April-October, indicating continental and temperature effects. Surface water was enriched in stable water isotopes from upstream to downstream sites due to progressive evaporation. Stable water isotopes in groundwater indicated that recharge occurs mainly during winter and spring. A one-year data set is probably not sufficient to report the seasonality of groundwater recharge, but this survey can be used to identify the stable water isotopes framework in a weakly gauged basin for further hydrological and geochemical studies.

Proinsulin is stable at room temperature for 24 hours in EDTA: A clinical laboratory analysis (adAPT 3.

Directory of Open Access Journals (Sweden)

Jane Davidson

Full Text Available Reference laboratories advise immediate separation and freezing of samples for the assay of proinsulin, which limit its practicability for smaller centres. Following the demonstration that insulin and C-peptide are stable in EDTA at room temperature for at least 24hours, we undertook simple stability studies to establish whether the same might apply to proinsulin.Venous blood samples were drawn from six adult women, some fasting, some not, aliquoted and assayed immediately and after storage at either 4°C or ambient temperature for periods from 2h to 24h.There was no significant variation or difference with storage time or storage condition in either individual or group analysis.Proinsulin appears to be stable at room temperature in EDTA for at least 24h. Immediate separation and storage on ice of samples for proinsulin assay is not necessary, which will simplify sample transport, particularly for multicentre trials.

Tooth enamel stable isotopes of Holocene and Pleistocene fossil fauna reveal glacial and interglacial paleoenvironments of hominins in Indonesia

Science.gov (United States)

Janssen, Renée; Joordens, Josephine C. A.; Koutamanis, Dafne S.; Puspaningrum, Mika R.; de Vos, John; van der Lubbe, Jeroen H. J. L.; Reijmer, John J. G.; Hampe, Oliver; Vonhof, Hubert B.

2016-07-01

The carbon (δ13C) and oxygen (δ18O) isotope compositions of fossilized animal tissues have become important proxies of paleodiet and paleoenvironment, but such stable isotope studies have not yet been extensively applied to the fossil assemblages of Sundaland (the biogeographical region comprising most of the Indonesian Archipelago). Here, we use the isotope composition of tooth enamel to investigate the diet and habitat of bovids, cervids, and suids from several Holocene and Pleistocene sites on Java and Sumatra. Our carbon isotope results indicate that individual sites are strongly dominated by either C3-browsers or C4-grazers. Herbivores from the Padang Highlands (Sumatra) and Hoekgrot (Java) cave faunas were mainly C3-browsers, while herbivores from Homo erectus-bearing sites Trinil and Sangiran (Java) utilized an almost exclusive C4 diet. The suids from all sites show a wide range of δ13C values, corroborating their omnivorous diet. For the dataset as a whole, oxygen and carbon isotope values are positively correlated. This suggests that isotopic enrichment of rainwater and vegetation δ18O values coincides with an increase of C4-grasslands. We interpret this pattern to mainly reflect the environmental contrast between glacial (drier, more C4) and interglacial (wetter, more C3) conditions. Intermediate herbivore δ13C values indicating mixed C3/C4 feeding is relatively rare, which we believe to reflect the abruptness of the transition between glacial and interglacial precipitation regimes in Sundaland. For seven Homo erectus bone samples we were not able distinguish between diagenetic overprint and original isotope values, underlining the need to apply this isotopic approach to Homo erectus tooth enamel instead of bone. Importantly, our present results on herbivore and omnivore faunas provide the isotopic framework that will allow interpretation of such Homo erectus enamel isotope data.

Stable isotope signatures reflect dietary diversity in European forest moths.

Science.gov (United States)

Adams, Marc-Oliver; Seifert, Carlo Lutz; Lehner, Lisamarie; Truxa, Christine; Wanek, Wolfgang; Fiedler, Konrad

2016-01-01

Information on larval diet of many holometabolous insects remains incomplete. Carbon (C) and nitrogen (N) stable isotope analysis in adult wing tissue can provide an efficient tool to infer such trophic relationships. The present study examines whether moth feeding guild affiliations taken from literature are reflected in isotopic signatures. Non-metric multidimensional scaling and permutational analysis of variance indicate that centroids of dietary groups differ significantly. In particular, species whose larvae feed on mosses or aquatic plants deviated from those that consumed vascular land plants. Moth δ(15)N signatures spanned a broader range, and were less dependent on species identity than δ(13)C values. Comparison between moth samples and ostensible food sources revealed heterogeneity in the lichenivorous guild, indicating only Lithosia quadra as an obligate lichen feeder. Among root-feeding Agrotis segetum, some specimens appear to have developed on crop plants in forest-adjacent farm land. Reed-feeding stem-borers may partially rely on intermediary trophic levels such as fungal or bacterial growth. Diagnostic partitioning of moth dietary guilds based on isotopic signatures alone could not be achieved, but hypotheses on trophic relationships based on often vague literature records could be assessed with high resolution. Hence, the approach is well suited for basic categorization of moths where diet is unknown or notoriously difficult to observe (i.e. Microlepidoptera, lichen-feeders).

A study on amphiphilic fluorinated block copolymer in graphite exfoliation using supercritical CO2 for stable graphene dispersion.

Science.gov (United States)

Kim, Young Hyun; Lee, Hyang Moo; Choi, Sung Wook; Cheong, In Woo

2018-01-15

In this study, poly(2,2,2-trifluoroethyl methacrylate)-block-poly(4-vinylpyridine) (PTFEMA-b-PVP) was synthesized by stepwise reversible addition-fragmentation chain transfer (RAFT) polymerization for the preparation of graphene by the exfoliation of graphite nanoplatelets (GPs) in supercritical CO 2 (SCCO 2 ). Two different block copolymers (low and high molecular weights) were prepared with the same block ratio and used at different concentrations in the SCCO 2 process. The amount of PTFEMA-b-PVP adsorbed on the GPs and the electrical conductivity of the SCCO 2 -treated GP samples were evaluated using thermogravimetric analysis (TGA) and four-point probe method, respectively. All GP samples treated with SCCO 2 were then dispersed in methanol and the dispersion stability was investigated using online turbidity measurements. The concentration and morphology of few-layer graphene stabilized with PTFEMA-b-PVP in the supernatant solution were investigated by gravimetry, scanning electron microscopy, and Raman spectroscopy. Destabilization study of the graphene dispersions revealed that the longer block copolymer exhibited better affinity for graphene, resulting in a higher yield of stable graphene with minimal defects. Copyright © 2017 Elsevier Inc. All rights reserved.

Radappertization of ready-to-eat shelf-stable, traditional Indian bread - Methi Paratha

Science.gov (United States)

Bhoir, Shraddha A.; Muppalla, Shobita R.; Kanatt, Sweetie R.; Chawla, S. P.; Sharma, Arun

2015-06-01

Shelf-stable ready-to-eat (RTE) Methi Paratha (flavored Indian unleavened flat bread) was developed using combination of hurdles including radiation processing. The Methi Paratha was prepared using dough containing wheat flour, dried fenugreek leaves and spices. The samples were vacuum packed in multi-layered pouches and irradiated at 25 kGy in frozen conditions. Samples were evaluated for microbiological counts, lipid peroxidation and sensory attributes during storage under ambient conditions. Samples were found to be devoid of any viable microorganism throughout the storage period of 180 days. The thiobarbituric acid reactive substances (TBARS) value which indicates lipid peroxidation of samples did not show any significant increase with time. The Methi Paratha was found to be acceptable by the evaluating panelists.

Sample vial inserts: A better approach for sampling heterogeneous slurry samples in the SRS Defense Waste Processing Facility

International Nuclear Information System (INIS)

Coleman, C.J.; Goode, S.R.

1996-01-01

A convenient and effective new approach for analyzing DWPF samples involves the use of inserts with volumes of 1.5--3 ml placed in the neck of 14 ml sample vials. The inserts have rims that conform to the rim of the vials so that they sit straight and stable in the vial. The DWPF tank sampling system fills the pre-weighed insert rather than the entire vial, so the vial functions only as the insert holder. The shielded cell operator then removes the vial cap and decants the insert containing the sample into a plastic bottle, crucible, etc., for analysis. Inert materials such as Teflon, plastic, and zirconium are used for the insert so it is unnecessary to separate the insert from the sample for most analyses. The key technique advantage of using inserts to take DWPF samples versus filling sample vials is that it provides a convenient and almost foolproof way of obtaining and handling small volumes of slurry samples in a shielded cell without corrupting the sample. Since the insert allows the entire sample to be analyzed, this approach eliminates the errors inherent with subsampling heterogeneous slurries that comprise DWPF samples. Slurry samples can then be analyzed with confidence. Analysis times are dramatically reduced by eliminating the drying and vitrification steps normally used to produce a homogeneous solid sample. Direct dissolution and elemental analysis of slurry samples are achieved in 8 hours or less compared with 40 hours for analysis of vitrified slurry samples. Comparison of samples taken in inserts versus full vials indicate that the insert does not significantly affect sample composition

Stability of carboxyhemoglobin in stored and mailed blood samples.

Science.gov (United States)

Hampson, Neil B

2008-02-01

Elevated blood carboxyhemoglobin (COHb) levels are used to confirm a clinical diagnosis of exposure to carbon monoxide (CO) and, in some instances, assess severity of poisoning. However, many hospital laboratories cannot measure COHb because they do not have CO-oximeters. In such instances, blood samples are often sent to outside laboratories or with a transported patient for measurement at the receiving hospital. This study was conducted to assess the stability of COHb in stored and mailed blood samples anticoagulated with heparin. Adult human blood was drawn into standard sample tubes anticoagulated with sodium heparin. Carbon monoxide gas was infused to raise the COHb level to 25% to 35%. Samples were then refrigerated or stored at room temperature, and serial COHb determinations were performed for 28 days. Additional samples were measured after being mailed locally or across the United States and back. No significant changes in COHb levels were seen in samples stored either in refrigeration or at room temperature over a period of 28 days or in samples shipped without refrigeration locally or across the United States. Carboxyhemoglobin levels in whole blood samples anticoagulated with heparin are stable with or without refrigeration for up to 4 weeks. If COHb measurement capability is not available, such samples may be shipped or transported with patients with confidence that the COHb level will be stable when measured at a later time.

Stable particles

International Nuclear Information System (INIS)

Samios, N.P.

1993-01-01

I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

Insufficient control of heart rate in stable coronary artery disease patients in Latvia

Directory of Open Access Journals (Sweden)

Inga Balode

2014-01-01

Conclusions: Despite the wide use of beta-blockers, HR is insufficiently controlled in the analyzed sample of stable CAD patients in Latvia. Target HR ≤60 bpm is achieved only in 25% of the patients while more than one third have increased HR ≥70 bpm.

Influence of horse stable environment on human airways

Directory of Open Access Journals (Sweden)

Pringle John

2009-05-01

Full Text Available Abstract Background Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. Methods The horse stable environment and stable-workers (n = 13 in one stable were investigated three times; first in the winter, second in the interjacent late summer and the third time in the following winter stabling period. The stable measurements included levels of ammonia, hydrogen sulphide, total and respirable dust, airborne horse allergen, microorganisms, endotoxin and glucan. The stable-workers completed a questionnaire on respiratory symptoms, underwent nasal lavage with subsequent analysis of inflammation markers, and performed repeated measurements of pulmonary function. Results Measurements in the horse stable showed low organic dust levels and high horse allergen levels. Increased viable level of fungi in the air indicated a growing source in the stable. Air particle load as well as 1,3-β-glucan was higher at the two winter time-points, whereas endotoxin levels were higher at the summer time-point. Two stable-workers showed signs of bronchial obstruction with increased PEF-variability, increased inflammation biomarkers relating to reported allergy, cold or smoking and reported partly work-related symptoms. Furthermore, two other stable-workers reported work-related airway symptoms, of which one had doctor's diagnosed asthma which was well treated. Conclusion Biomarkers involved in the development of airway diseases have been studied in relation to

Influence of horse stable environment on human airways.

Science.gov (United States)

Elfman, Lena; Riihimäki, Miia; Pringle, John; Wålinder, Robert

2009-05-25

Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. The horse stable environment and stable-workers (n = 13) in one stable were investigated three times; first in the winter, second in the interjacent late summer and the third time in the following winter stabling period. The stable measurements included levels of ammonia, hydrogen sulphide, total and respirable dust, airborne horse allergen, microorganisms, endotoxin and glucan. The stable-workers completed a questionnaire on respiratory symptoms, underwent nasal lavage with subsequent analysis of inflammation markers, and performed repeated measurements of pulmonary function. Measurements in the horse stable showed low organic dust levels and high horse allergen levels. Increased viable level of fungi in the air indicated a growing source in the stable. Air particle load as well as 1,3-beta-glucan was higher at the two winter time-points, whereas endotoxin levels were higher at the summer time-point. Two stable-workers showed signs of bronchial obstruction with increased PEF-variability, increased inflammation biomarkers relating to reported allergy, cold or smoking and reported partly work-related symptoms. Furthermore, two other stable-workers reported work-related airway symptoms, of which one had doctor's diagnosed asthma which was well treated. Biomarkers involved in the development of airway diseases have been studied in relation to environmental exposure levels in equine stables. Respirable dust and 1

Stable configurations in social networks

Science.gov (United States)

Bronski, Jared C.; DeVille, Lee; Ferguson, Timothy; Livesay, Michael

2018-06-01

We present and analyze a model of opinion formation on an arbitrary network whose dynamics comes from a global energy function. We study the global and local minimizers of this energy, which we call stable opinion configurations, and describe the global minimizers under certain assumptions on the friendship graph. We show a surprising result that the number of stable configurations is not necessarily monotone in the strength of connection in the social network, i.e. the model sometimes supports more stable configurations when the interpersonal connections are made stronger.

Development of Stable Isotope Technology

International Nuclear Information System (INIS)

Jeong, Do Young; Kim, Cheol Jung; Han, Jae Min

2009-03-01

KAERI has obtained an advanced technology with singular originality for laser stable isotope separation. Objectives for this project are to get production technology of Tl-203 stable isotope used for medical application and are to establish the foundation of the pilot system, while we are taking aim at 'Laser Isotope Separation Technology to make resistance to the nuclear proliferation'. And we will contribute to ensuring a nuclear transparency in the world society by taking part in a practical group of NSG and being collaboration with various international groups related to stable isotope separation technology

Separation of polybrominated diphenyl ethers in fish for compound-specific stable carbon isotope analysis

Energy Technology Data Exchange (ETDEWEB)

Zeng, Yan-Hong [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing, 100049 (China); Luo, Xiao-Jun, E-mail: luoxiaoj@gig.ac.cn [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chen, Hua-Shan; Wu, Jiang-Ping; Chen, She-Jun; Mai, Bi-Xian [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

2012-05-15

A separation and isotopic analysis method was developed to accurately measure the stable carbon isotope ratios of polybrominated diphenyl ethers (PBDEs) with three to six substituted bromine atoms in fish samples. Sample extracts were treated with concentrated sulfuric acid to remove lipids, purified using complex silica gel column chromatography, and finally processed using alumina/silica (Al/Si) gel column chromatography. The purities of extracts were verified by gas chromatography and mass spectrometry (GC-MS) in the full-scan mode. The average recoveries of all compounds across the purification method were between 60% and 110%, with the exception of BDE-154. The stable carbon isotopic compositions of PBDEs can be measured with a standard deviation of less than 0.5 Per-Mille-Sign . No significant isotopic fraction was found during the purification of the main PBDE congeners. A significant change in the stable carbon isotope ratio of BDE-47 was observed in fish carcasses compared to the original isotopic signatures, implying that PBDE stable carbon isotopic compositions can be used to trace the biotransformation of PBDEs in biota. - Highlights: Black-Right-Pointing-Pointer A method for the purification of PBDEs for CSIA was developed. Black-Right-Pointing-Pointer The {delta}{sup 13}C of PBDE congeners can be measured with a standard deviation of less than 0.5 Per-Mille-Sign . Black-Right-Pointing-Pointer Common carp were exposed to a PBDE mixture to investigate debromination. Black-Right-Pointing-Pointer Ratios of the {delta}{sup 13}C values can be used to trace the debromination of PBDE in fish.

Invasive mussels alter the littoral food web of a large lake: stable isotopes reveal drastic shifts in sources and flow of energy.

Directory of Open Access Journals (Sweden)

Ted Ozersky

Full Text Available We investigated how establishment of invasive dreissenid mussels impacted the structure and energy sources of the littoral benthic food web of a large temperate lake. We combined information about pre- and postdreissenid abundance, biomass, and secondary production of the littoral benthos with results of carbon and nitrogen stable isotope analysis of archival (predreissenid and recent (postdreissenid samples of all common benthic taxa. This approach enabled us to determine the importance of benthic and sestonic carbon to the littoral food web before, and more than a decade after dreissenid establishment. Long term dreissenid presence was associated with a 32-fold increase in abundance, 6-fold increase in biomass, and 14-fold increase in secondary production of the littoral benthos. Dreissenids comprised a large portion of the post-invasion benthos, making up 13, 38, and 56% of total abundance, biomass, and secondary production, respectively. The predreissenid food web was supported primarily by benthic primary production, while sestonic material was relatively more important to the postdreissenid food web. The absolute importance of both sestonic material and benthic primary production to the littoral benthos increased considerably following dreissenid establishment. Our results show drastic alterations to food web structure and suggest that dreissenid mussels redirect energy and material from the water column to the littoral benthos both through biodeposition of sestonic material as well as stimulation of benthic primary production.

Biopolymers for sample collection, protection, and preservation.

Science.gov (United States)

Sorokulova, Iryna; Olsen, Eric; Vodyanoy, Vitaly

2015-07-01

One of the principal challenges in the collection of biological samples from air, water, and soil matrices is that the target agents are not stable enough to be transferred from the collection point to the laboratory of choice without experiencing significant degradation and loss of viability. At present, there is no method to transport biological samples over considerable distances safely, efficiently, and cost-effectively without the use of ice or refrigeration. Current techniques of protection and preservation of biological materials have serious drawbacks. Many known techniques of preservation cause structural damages, so that biological materials lose their structural integrity and viability. We review applications of a novel bacterial preservation process, which is nontoxic and water soluble and allows for the storage of samples without refrigeration. The method is capable of protecting the biological sample from the effects of environment for extended periods of time and then allows for the easy release of these collected biological materials from the protective medium without structural or DNA damage. Strategies for sample collection, preservation, and shipment of bacterial, viral samples are described. The water-soluble polymer is used to immobilize the biological material by replacing the water molecules within the sample with molecules of the biopolymer. The cured polymer results in a solid protective film that is stable to many organic solvents, but quickly removed by the application of the water-based solution. The process of immobilization does not require the use of any additives, accelerators, or plastifiers and does not involve high temperature or radiation to promote polymerization.

Lead and stable Pb-isotope characteristics of tropical soils in north-eastern Brazil

International Nuclear Information System (INIS)

Schucknecht, Anne; Matschullat, Jörg; Reimann, Clemens

2011-01-01

Stable Pb-isotope ratios are widely used as tracers for Pb-sources in the environment. Recently, a few publications have challenged the predominating view of environmental applications of Pb-isotopes. Present applications of Pb-isotopic tracers in soils largely represent the northern hemisphere. This study focuses on tropical soils from Paraíba, north-eastern Brazil. Lead concentrations and Pb-isotopic signatures (both 7N HNO 3 ) were determined at 30 sites along a 327 km E–W-transect, from the Atlantic coast at João Pessoa to some kilometers west of Patos, to identify possible processes for the observed (and anticipated) distribution pattern. Thirty samples each of litter (ORG) and top mineral soil (TOP) were taken on pasture land at suitable distance from roads or other potential contamination sources. Lead-content was determined by inductively-coupled plasma atomic emission spectrometry (ICP-AES) and the ratios of 206 Pb/ 207 Pb, 206 Pb/ 208 Pb, and 208 Pb/ 207 Pb by ICP-sector field mass spectrometry (ICP-SFMS). Both sample materials show similarly low Pb-concentrations with a lower median in the ORG samples (ORG 3.4 mg kg −1 versus TOP 6.9 mg kg −1 ). The 206 Pb/ 207 Pb ratios revealed a large spread along the transect with median 206 Pb/ 207 Pb ratios of 1.160 (ORG) and 1.175 (TOP). The 206 Pb/ 207 Pb ratios differ noticeably between sample sites located in the Atlantic Forest biome along the coast and sample sites in the inland Caatinga biome. The “forest” sites were characterised by a significant lower median and a lower spread in the 206 Pb/ 207 Pb and 206 Pb/ 208 Pb ratios compared to the Caatinga sites. Results indicate a very restricted influence of anthropogenic activities (individual sites only). The main process influencing the spatial variability of Pb-isotope ratios is supposed to be precipitation-dependent bioproductivity and weathering.

Stable Isotopes Reveal Rapid Enamel Elongation (Amelogenesis) Rates for the Early Cretaceous Iguanodontian Dinosaur Lanzhousaurus magnidens.

Science.gov (United States)

Suarez, Celina A; You, Hai-Lu; Suarez, Marina B; Li, Da-Qing; Trieschmann, J B

2017-11-10

Lanzhousaurus magnidens, a large non-hadrosauriform iguanodontian dinosaur from the Lower Cretaceous Hekou Group of Gansu Province, China has the largest known herbivorous dinosaur teeth. Unlike its hadrosauriform relatives possessing tooth batteries of many small teeth, Lanzhousaurus utilized a small number (14) of very large teeth (~10 cm long) to create a large, continuous surface for mastication. Here we investigate the significance of Lanzhousaurus in the evolutionary history of iguanodontian-hadrosauriform transition by using a combination of stable isotope analysis and CT imagery. We infer that Lanzhousaurus had a rapid rate of tooth enamel elongation or amelogenesis at 0.24 mm/day with dental tissues common to other Iguanodontian dinosaurs. Among ornithopods, high rates of amelogenesis have been previously observed in hadrosaurids, where they have been associated with a sophisticated masticatory apparatus. These data suggest rapid amelogenesis evolved among non-hadrosauriform iguanodontians such as Lanzhousaurus, representing a crucial step that was exapted for the evolution of the hadrosaurian feeding mechanism.

Unpredictably Stable

DEFF Research Database (Denmark)

Failla, Virgilio; Melillo, Francesca; Reichstein, Toke

2014-01-01

Is entrepreneurship a more stable career choice for high employment turnover individuals? We find that a transition to entrepreneurship induces a shift towards stayer behavior and identify job matching, job satisfaction and lock-in effects as main drivers. These findings have major implications...

Discrimination factors of carbon and nitrogen stable isotopes in meerkat feces

Directory of Open Access Journals (Sweden)

Shaena Montanari

2017-06-01

Full Text Available Stable isotope analysis of feces can provide a non-invasive method for tracking the dietary habits of nearly any mammalian species. While fecal samples are often collected for macroscopic and genetic study, stable isotope analysis can also be applied to expand the knowledge of species-specific dietary ecology. It is somewhat unclear how digestion changes the isotope ratios of animals’ diets, so more controlled diet studies are needed. To date, most diet-to-feces controlled stable isotope experiments have been performed on herbivores, so in this study I analyzed the carbon and nitrogen stable isotope ratios in the diet and feces of the meerkat (Suricata suricatta, a small omnivorous mammal. The carbon trophic discrimination factor between diet and feces (Δ13Cfeces is calculated to be 0.1 ± 1.5‰, which is not significantly different from zero, and in turn, not different than the dietary input. On the other hand, the nitrogen trophic discrimination factor (Δ15Nfeces is 1.5 ± 1.1‰, which is significantly different from zero, meaning it is different than the average dietary input. Based on data generated in this experiment and a review of the published literature, carbon isotopes of feces characterize diet, while nitrogen isotope ratios of feces are consistently higher than dietary inputs, meaning a discrimination factor needs to be taken into account. The carbon and nitrogen stable isotope values of feces are an excellent snapshot of diet that can be used in concert with other analytical methods to better understand ecology, diets, and habitat use of mammals.

Stable isotope signatures reflect competitiveness between trees under changed CO2/O3 regimes

International Nuclear Information System (INIS)

Grams, T.E.E.; Matyssek, R.

2010-01-01

Here we synthesize key findings from a series of experiments to gain new insight on inter-plant competition between juvenile beech (Fagus sylvatica) and spruce (Picea abies) under the influence of increased O 3 and CO 2 concentrations. Competitiveness of plants was quantified and mechanistically interpreted as space-related resource investments and gains. Stable isotopes were addressed as temporal integrators of plant performance, such as photosynthesis and its relation to water use and nitrogen uptake. In the weaker competitor, beech, efficiency in space-related aboveground resource investment was decreased in competition with spruce and positively related to Δ 13 C, as well as stomatal conductance, but negatively related to δ 18 O. Likewise, our synthesis revealed that strong belowground competition for water in spruce was paralleled in this species by high N assimilation capacity. We suggest combining the time-integrative potential of stable isotopes with space-related investigations of competitiveness to accomplish mechanistic understanding of plant competition for resources. - Combination of space-related concepts of competitiveness with stable isotopes has potential to clarify mechanisms of competition.

Investigating differences in light stable isotopes between Thai jasmine rice and Sungyod rice

Science.gov (United States)

Kukusamude, C.; Kongsri, S.

2017-10-01

We report the differences in light stable isotopes between two kinds of Thai rice (Thai jasmine and Sungyod rice). Thai jasmine rice and Sungyod rice were cultivated in the northeast and the south of Thailand. Light isotopes including 13C, 15N and 18O of Thai jasmine rice and Sungyod rice samples were carried out using isotope ratio mass spectrometry (IRMS). Thai jasmine rice (Khao Dawk Mali 105) was cultivated from Thung Kula Rong Hai area, whereas Sungyod rice was cultivated from Phathalung province. Hypothesis testing of difference of each isotope between Thai jasmine rice and Sungyod rice was also studied. The study was the feasibility test whether the light stable isotopes can be the variables to identify Thai jasmine rice and Sungyod rice. The result shows that there was difference in the isotope patterns of Thai jasmine rice and Sungyod rice. Our results may provide the useful information in term of stable isotope profiles of Thai rice.

Stable isotope (2H, 17O, 18O) and hydro chemical patterns of precipitation collected in weekly resolution at Hannover, Germany

Science.gov (United States)

Koeniger, Paul; Himmelsbach, Thomas

2016-04-01

Long-term observations of stable isotopes (δ18O and δ2H) in precipitation were initiated in May 2008 at the Federal Institute of Geosciences and Natural Resources (BGR) in Hannover, Germany. In 2014 all precipitation samples were re-analyzed because a purchase of a new laser spectrometer (Picarro L2140-i) now allowed measurements of δ17O and a calculation of the 17O-excess parameter. Starting in October 2015 a routine analysis of hydro chemical parameters was added whenever enough sample aliquot was available (major ions, trace elements). A discussion of the stable isotope data of the seven year series of weekly precipitation samples (n = 370) will be presented. Beneath general patterns (seasonality and trends) we also focus on importance of amount weighing procedures, corrections for minor rain amounts, aspects of sample storage and re-analyzes, as well as impacts through changes in analytical equipment (IRMS, CRD spectroscopy) which is visible from the data. For stable isotopes a Thermo Fisher delta plus IRMS (Gasbench and H-Device) was used until 2011 and from 2012 on a Picarro L2120-i water vapor analyzer with long-term accuracies for quality check samples better than 0.2‰ and 0.8‰ for δ18O and δ2H, respectively.

Multi-scale sampling to evaluate assemblage dynamics in an oceanic marine reserve.

Science.gov (United States)

Thompson, Andrew R; Watson, William; McClatchie, Sam; Weber, Edward D

2012-01-01

To resolve the capacity of Marine Protected Areas (MPA) to enhance fish productivity it is first necessary to understand how environmental conditions affect the distribution and abundance of fishes independent of potential reserve effects. Baseline fish production was examined from 2002-2004 through ichthyoplankton sampling in a large (10,878 km(2)) Southern Californian oceanic marine reserve, the Cowcod Conservation Area (CCA) that was established in 2001, and the Southern California Bight as a whole (238,000 km(2) CalCOFI sampling domain). The CCA assemblage changed through time as the importance of oceanic-pelagic species decreased between 2002 (La Niña) and 2003 (El Niño) and then increased in 2004 (El Niño), while oceanic species and rockfishes displayed the opposite pattern. By contrast, the CalCOFI assemblage was relatively stable through time. Depth, temperature, and zooplankton explained more of the variability in assemblage structure at the CalCOFI scale than they did at the CCA scale. CalCOFI sampling revealed that oceanic species impinged upon the CCA between 2002 and 2003 in association with warmer offshore waters, thus explaining the increased influence of these species in the CCA during the El Nino years. Multi-scale, spatially explicit sampling and analysis was necessary to interpret assemblage dynamics in the CCA and likely will be needed to evaluate other focal oceanic marine reserves throughout the world.

Understanding repetitive travel mode choices in a stable context: A panel study approach

DEFF Research Database (Denmark)

Thøgersen, John

2006-01-01

It is argued that most travel mode choices are repetitive and made in a stable context. As an example, the everyday use of public transport is analyzed based on a panel survey with a random sample of about 1300 Danish residents interviewed up to three times in the period 1998-2000. The use...

Stable isotopic composition of East African lake waters

International Nuclear Information System (INIS)

Odada, E.O.

2001-01-01

The investigation of stable isotopic composition of East African lake waters was conducted by scientists from the Department of Geology, University of Nairobi, as part of the International Decade for the East African Lakes (IDEAL) project and in close collaboration with the scientists from Large Lakes Observatory of the University of Minnesota and the Isotope Hydrology Laboratory of the IAEA in Vienna. The Research Contract was part of the IAEA Co-ordinated Research Programme on Isotope Techniques in Lake Dynamics Investigations, and was sponsored by the Agency. Water and grab sediment samples were obtained from East African Lakes during the month of January and February 1994 and July/August 1995. Water samples were analysed for oxygen and deuterium isotopic composition at the IAEA Laboratories in Vienna, Austria. In this final paper we report the results of the study of oxygen and deuterium isotopic composition from the East African lake waters. (author)

Determining origin in a migratory marine vertebrate: a novel method to integrate stable isotopes and satellite tracking

Science.gov (United States)

Vander Zanden, Hannah B.; Tucker, Anton D.; Hart, Kristen M.; Lamont, Margaret M.; Fujisaki, Ikuko; Addison, David S.; Mansfield, Katherine L.; Phillips, Katrina F.; Wunder, Michael B.; Bowen, Gabriel J.; Pajuelo, Mariela; Bolten, Alan B.; Bjorndal, Karen A.

2015-01-01

Stable isotope analysis is a useful tool to track animal movements in both terrestrial and marine environments. These intrinsic markers are assimilated through the diet and may exhibit spatial gradients as a result of biogeochemical processes at the base of the food web. In the marine environment, maps to predict the spatial distribution of stable isotopes are limited, and thus determining geographic origin has been reliant upon integrating satellite telemetry and stable isotope data. Migratory sea turtles regularly move between foraging and reproductive areas. Whereas most nesting populations can be easily accessed and regularly monitored, little is known about the demographic trends in foraging populations. The purpose of the present study was to examine migration patterns of loggerhead nesting aggregations in the Gulf of Mexico (GoM), where sea turtles have been historically understudied. Two methods of geographic assignment using stable isotope values in known-origin samples from satellite telemetry were compared: 1) a nominal approach through discriminant analysis and 2) a novel continuous-surface approach using bivariate carbon and nitrogen isoscapes (isotopic landscapes) developed for this study. Tissue samples for stable isotope analysis were obtained from 60 satellite-tracked individuals at five nesting beaches within the GoM. Both methodological approaches for assignment resulted in high accuracy of foraging area determination, though each has advantages and disadvantages. The nominal approach is more appropriate when defined boundaries are necessary, but up to 42% of the individuals could not be considered in this approach. All individuals can be included in the continuous-surface approach, and individual results can be aggregated to identify geographic hotspots of foraging area use, though the accuracy rate was lower than nominal assignment. The methodological validation provides a foundation for future sea turtle studies in the region to inexpensively

Stable isotope ratiometer-multiple ion detector (SIRMID) unit for quantitative and qualitative stable isotope studies by gas chromatography-mass spectrometry

International Nuclear Information System (INIS)

Klein, P.D.; Haumann, J.R.; Hachey, D.L.

1975-01-01

A stable isotope ratiometer-multiple ion detector (SIRMID) unit which can drive existing gas chromatograph-quadrupole or magnetic sector mass spectrometers to monitor up to six ions in turn is described. Each of the three pairs of ions can be selected for quantitation; thus three different or successive components can be analyzed in a single GC run. A background subtraction option permits the ion intensity in the absence of sample to be subtracted automatically during sample measurement. Displays of accumulated counts and isotope ratio are updated twice per second during the measurement and can be printed out at its conclusion. All six ions can be monitored in the analog mode by parallel outputs to a multipen recorder. Experience gained in the construction of this prototype indicates that SIRMID units could be commercially available for $10K, or about 1 / 3 rd to 1 / 6 th of the cost of even an inexpensive computer system. (U.S.)

Formulation and utilization of choline based samples for dissolution dynamic nuclear polarization

DEFF Research Database (Denmark)

Bowen, Sean; Ardenkjær-Larsen, Jan Henrik

2013-01-01

their performance to more traditional sample formulations. Choline yields stable samples with exceptional polarization performance while simultaneously offering the capability to easily remove the choline after dissolution, perform experiments with the hyperpolarized choline, or anything in between....

Global Metabolomics of the Placenta Reveals Distinct Metabolic Profiles between Maternal and Fetal Placental Tissues Following Delivery in Non-Labored Women

Directory of Open Access Journals (Sweden)

Jacquelyn M. Walejko

2018-01-01

Full Text Available We evaluated the metabolic alterations in maternal and fetal placental tissues from non-labored women undergoing cesarean section using samples collected from 5 min to 24 h following delivery. Using 1H-NMR, we identified 14 metabolites that significantly differed between maternal and fetal placental tissues (FDR-corrected p-value < 0.05, with 12 metabolites elevated in the maternal tissue, reflecting the flux of these metabolites from mother to fetus. In the maternal tissue, 4 metabolites were significantly altered at 15 min, 10 metabolites at 30 min, and 16 metabolites at 1 h postdelivery, while 11 metabolites remained stable over 24 h. In contrast, in the fetal placenta tissue, 1 metabolite was significantly altered at 15 min, 2 metabolites at 30 min, and 4 metabolites at 1 h postdelivery, while 22 metabolites remained stable over 24 h. Our study provides information on the metabolic profiles of maternal and fetal placental tissues delivered by cesarean section and reveals that there are different metabolic alterations in the maternal and fetal tissues of the placenta following delivery.

Stable rotating dipole solitons in nonlocal media

DEFF Research Database (Denmark)

Lopez-Aguayo, Servando; Skupin, Stefan; Desyatnikov, Anton S.

2006-01-01

We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons.......We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons....

It takes time to see the menu from the body: an experiment on stable isotope composition in freshwater crayfishes

Directory of Open Access Journals (Sweden)

Jussila J.

2015-01-01

Full Text Available For many applications and ecological studies in which wild individuals are brought to laboratory it would be essential to know accurately how fast novel diet is reflected in composition of different tissues. To study the effects of two different diets on the stable isotope composition of freshwater crayfish muscle and hemolymph, we conducted a three month experiment on noble crayfish (Astacus astacus and signal crayfish (Pacifastacus leniusculus by feeding them sweet corn (Zea mays or Baltic herring (Clupea harengus membras as novel food. During the experiment, the crayfish were given 0.4 g of selected food daily and the amount consumed was recorded. The samples for the stable isotope analyses were taken at the commencement of the experiment (initial control and three times (hemolymph or twice (muscle tissue during the experiment. We found that stable isotope changes can be similarly, and rather slowly, detected from muscle tissue and hemolymph under studied conditions. Hemolymph sampling, being non-lethal, can be recommended as a practical sampling method. Our results confirm earlier reports according to which diet changes reflect to crayfish isotope ratios slowly implying that isotope ratios indicate long-term diet.

A Method for Determining the Content of Glycoproteins in Biological Samples

Directory of Open Access Journals (Sweden)

Yang Gao

2016-11-01

Full Text Available The glycoprotein purified from the mycelium extract of Tremella fuciformis was marked with iodine through the iodine substitution reaction. The content of iodine, which is indicative of the amount of the marked tremella glycoprotein (ITG, was detected with Inductively coupled plasma mass spectrometry (ICP-MS. The method was found to be stable, sensitive, and accurate at detecting the content of iodine-substituted glycoprotein, and was used in the quantitative analysis of biological samples, including blood and organs. Different biological samples were collected from rats after oral administration of ITG, and were tested for iodine content by ICP-MS to calculate the amount of ITG in the samples. The results suggested that ICP-MS is a sensitive, stable, and accurate method for detection of iodinated glycoproteins in blood and organs.

Investigation of Chemical and Physical Changes to Bioapatite During Fossilization Using Trace Element Geochemistry, Infrared Spectroscopy and Stable Isotopes

Science.gov (United States)

Suarez, C. A.; Kohn, M. J.

2013-12-01

Bioapatite in the form of vertebrate bone can be used for a wide variety of paleo-proxies, from determination of ancient diet to the isotopic composition of meteoric water. Bioapatite alteration during diagenesis is a constant barrier to the use of fossil bone as a paleo-proxy. To elucidate the physical and chemical alteration of bone apatite during fossilization, we analyzed an assortment of fossil bones of different ages for trace elements, using LA-ICP-MS, stable isotopes, and reflected IR spectroscopy. One set of fossil bones from the Pleistocene of Idaho show a diffusion recrystallization profile, however, rare earth element (REE) profiles indicate diffusion adsorption. This suggests that REE diffusion is controlled by changing (namely decreasing) boundary conditions (i.e. decreasing concentration of REE in surrounding pore fluids). Reflected IR analysis along this concentration profile reveal that areas high in U have lost type A carbonate from the crystal structure in addition to water and organics. Stable isotopic analysis of carbon and oxygen will determine what, if any, change in the isotopic composition of the carbonate component of apatite has occurred do to the diffusion and recrystallization process. Analysis of much older bone from the Cretaceous of China reveal shallow REE and U concentration profiles and very uniform reflected IR spectra with a significant loss of type A carbonate throughout the entire bone cortex. Analysis of stable isotopes through the bone cortex will be compared to the stable isotopes collected from the Pleistocene of Idaho.

A soil sampling reference site: The challenge in defining reference material for sampling

International Nuclear Information System (INIS)

De Zorzi, Paolo; Barbizzi, Sabrina; Belli, Maria; Fajgelj, Ales; Jacimovic, Radojko; Jeran, Zvonka; Sansone, Umberto; Perk, Marcel van der

2008-01-01

In the frame of the international SOILSAMP project, funded and coordinated by the Italian Environmental Protection Agency, an agricultural area was established as a reference site suitable for performing soil sampling inter-comparison exercises. The reference site was characterized for trace element content in soil, in terms of the spatial and temporal variability of their mass fraction. Considering that the behaviour of long-lived radionuclides in soil can be expected to be similar to that of some stable trace elements and that the distribution of these trace elements in soil can simulate the distribution of radionuclides, the reference site characterised in term of trace elements, can be also used to compare the soil sampling strategies developed for radionuclide investigations

A soil sampling reference site: The challenge in defining reference material for sampling

Energy Technology Data Exchange (ETDEWEB)

De Zorzi, Paolo [Agenzia per la Protezione dell' Ambiente e per i Servizi Tecnici (APAT), Servizio Metrologia Ambientale, Via di Castel Romano, Rome 100-00128 (Italy)], E-mail: paolo.dezorzi@apat.it; Barbizzi, Sabrina; Belli, Maria [Agenzia per la Protezione dell' Ambiente e per i Servizi Tecnici (APAT), Servizio Metrologia Ambientale, Via di Castel Romano, Rome 100-00128 (Italy); Fajgelj, Ales [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, Vienna A-1400 (Austria); Jacimovic, Radojko; Jeran, Zvonka; Sansone, Umberto [Jozef Stefan Institute, Jamova 39, Ljubljana 1000 (Slovenia); Perk, Marcel van der [Department of Physical Geography, Utrecht University, P.O. Box 80115, TC Utrecht 3508 (Netherlands)

2008-11-15

In the frame of the international SOILSAMP project, funded and coordinated by the Italian Environmental Protection Agency, an agricultural area was established as a reference site suitable for performing soil sampling inter-comparison exercises. The reference site was characterized for trace element content in soil, in terms of the spatial and temporal variability of their mass fraction. Considering that the behaviour of long-lived radionuclides in soil can be expected to be similar to that of some stable trace elements and that the distribution of these trace elements in soil can simulate the distribution of radionuclides, the reference site characterised in term of trace elements, can be also used to compare the soil sampling strategies developed for radionuclide investigations.

A soil sampling reference site: the challenge in defining reference material for sampling.

Science.gov (United States)

de Zorzi, Paolo; Barbizzi, Sabrina; Belli, Maria; Fajgelj, Ales; Jacimovic, Radojko; Jeran, Zvonka; Sansone, Umberto; van der Perk, Marcel

2008-11-01

In the frame of the international SOILSAMP project, funded and coordinated by the Italian Environmental Protection Agency, an agricultural area was established as a reference site suitable for performing soil sampling inter-comparison exercises. The reference site was characterized for trace element content in soil, in terms of the spatial and temporal variability of their mass fraction. Considering that the behaviour of long-lived radionuclides in soil can be expected to be similar to that of some stable trace elements and that the distribution of these trace elements in soil can simulate the distribution of radionuclides, the reference site characterised in term of trace elements, can be also used to compare the soil sampling strategies developed for radionuclide investigations.

Selecting the best stable isotope mixing model to estimate grizzly bear diets in the Greater Yellowstone Ecosystem.

Science.gov (United States)

Hopkins, John B; Ferguson, Jake M; Tyers, Daniel B; Kurle, Carolyn M

2017-01-01

Past research indicates that whitebark pine seeds are a critical food source for Threatened grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE). In recent decades, whitebark pine forests have declined markedly due to pine beetle infestation, invasive blister rust, and landscape-level fires. To date, no study has reliably estimated the contribution of whitebark pine seeds to the diets of grizzlies through time. We used stable isotope ratios (expressed as δ13C, δ15N, and δ34S values) measured in grizzly bear hair and their major food sources to estimate the diets of grizzlies sampled in Cooke City Basin, Montana. We found that stable isotope mixing models that included different combinations of stable isotope values for bears and their foods generated similar proportional dietary contributions. Estimates generated by our top model suggest that whitebark pine seeds (35±10%) and other plant foods (56±10%) were more important than meat (9±8%) to grizzly bears sampled in the study area. Stable isotope values measured in bear hair collected elsewhere in the GYE and North America support our conclusions about plant-based foraging. We recommend that researchers consider model selection when estimating the diets of animals using stable isotope mixing models. We also urge researchers to use the new statistical framework described here to estimate the dietary responses of grizzlies to declines in whitebark pine seeds and other important food sources through time in the GYE (e.g., cutthroat trout), as such information could be useful in predicting how the population will adapt to future environmental change.

Investigating the Relationship between Stable Personality Characteristics and Automatic Imitation.

Science.gov (United States)

Butler, Emily E; Ward, Robert; Ramsey, Richard

2015-01-01

Automatic imitation is a cornerstone of nonverbal communication that fosters rapport between interaction partners. Recent research has suggested that stable dimensions of personality are antecedents to automatic imitation, but the empirical evidence linking imitation with personality traits is restricted to a few studies with modest sample sizes. Additionally, atypical imitation has been documented in autism spectrum disorders and schizophrenia, but the mechanisms underpinning these behavioural profiles remain unclear. Using a larger sample than prior studies (N=243), the current study tested whether performance on a computer-based automatic imitation task could be predicted by personality traits associated with social behaviour (extraversion and agreeableness) and with disorders of social cognition (autistic-like and schizotypal traits). Further personality traits (narcissism and empathy) were assessed in a subsample of participants (N=57). Multiple regression analyses showed that personality measures did not predict automatic imitation. In addition, using a similar analytical approach to prior studies, no differences in imitation performance emerged when only the highest and lowest 20 participants on each trait variable were compared. These data weaken support for the view that stable personality traits are antecedents to automatic imitation and that neural mechanisms thought to support automatic imitation, such as the mirror neuron system, are dysfunctional in autism spectrum disorders or schizophrenia. In sum, the impact that personality variables have on automatic imitation is less universal than initial reports suggest.

Investigating the Relationship between Stable Personality Characteristics and Automatic Imitation.

Directory of Open Access Journals (Sweden)

Emily E Butler

Full Text Available Automatic imitation is a cornerstone of nonverbal communication that fosters rapport between interaction partners. Recent research has suggested that stable dimensions of personality are antecedents to automatic imitation, but the empirical evidence linking imitation with personality traits is restricted to a few studies with modest sample sizes. Additionally, atypical imitation has been documented in autism spectrum disorders and schizophrenia, but the mechanisms underpinning these behavioural profiles remain unclear. Using a larger sample than prior studies (N=243, the current study tested whether performance on a computer-based automatic imitation task could be predicted by personality traits associated with social behaviour (extraversion and agreeableness and with disorders of social cognition (autistic-like and schizotypal traits. Further personality traits (narcissism and empathy were assessed in a subsample of participants (N=57. Multiple regression analyses showed that personality measures did not predict automatic imitation. In addition, using a similar analytical approach to prior studies, no differences in imitation performance emerged when only the highest and lowest 20 participants on each trait variable were compared. These data weaken support for the view that stable personality traits are antecedents to automatic imitation and that neural mechanisms thought to support automatic imitation, such as the mirror neuron system, are dysfunctional in autism spectrum disorders or schizophrenia. In sum, the impact that personality variables have on automatic imitation is less universal than initial reports suggest.

Ca{sub 2}Cr{sub 0.5}Ga{sub 1.5}O{sub 5}—An extremely redox-stable brownmillerite phase

Energy Technology Data Exchange (ETDEWEB)

Luo, Kun; Amano Patino, Midori; Hayward, Michael A., E-mail: michael.hayward@chem.ox.ac.uk

2015-02-15

Investigation of the Ca{sub 2}Cr{sub x}Ga{sub 2−x}O{sub 5} compositional series reveals a maximum chromium solubility of 25%. The most chromium rich composition, Ca{sub 2}Cr{sub 0.5}Ga{sub 1.5}O{sub 5}, adopts a brownmillerite-type anion deficient perovskite structure described in space group Pnma (a=5.368 Å, b=14.547 Å, c=5.593 Å). Neutron powder diffraction data reveals rigorous B-site cation order, with all of the tetrahedral coordination sites occupied exclusively by gallium and the octahedral coordination sites occupied by gallium or chromium. Annealing studies reveals Ca{sub 2}Cr{sub 0.5}Ga{sub 1.5}O{sub 5} is stable in both oxidizing (100% O{sub 2}) and reducing (5% H{sub 2} in N{sub 2}) conditions up to 800 °C, suggesting it could find application as a stable host lattice for fuel cell electrodes or electrolytes with suitable doping to enhance catalytic behaviour and/or anionic conductivity. - Graphical abstract: Ca{sub 2}Cr{sub 0.5}Ga{sub 1.5}O{sub 5}, adopts a brownmillerite-type anion deficient perovskite structure yet it is stable in both oxidizing (100% O{sub 2}) and reducing (5% H{sub 2} in N{sub 2}) conditions up to 800 °C. - Highlights: • Anion deficient oxide stable to both oxidation and reduction up to 800 °C. • Cation-ordered brownmillerite structure determined by powder neutron diffraction. • Low solubility of Cr{sup 3+} in framework due to spherical d{sup 3} electron configuration.

Changes of stable isotopes carbon-13 and nitrogen-15 in different tissues of cattle

International Nuclear Information System (INIS)

Sun Fengmei; Yu Hongxia; Wu Wei; Yang Shuming

2009-01-01

Stable isotope analysis is a potential tool for tracing food origin. The stable carbon and nitrogen isotope composition in different tissues of two varieties of cattle under the same culture condition were investigated. δ 13 C and δ 15 N values of different defatted muscle and crude fat, cattle tail hair, blood, liver and feed were determined by isotope ratio mass spectrometry, and statistical analysis was carried out. The results showed that stable isotopes of carbon and nitrogen composition was not affected by cattle variety; the δ 13 C values between different defatted muscle, blood, liver and cattle hair were not significantly different, but δ 15 N value in the liver was much higher than other muscle and the δ 13 C values didn't show difference among all the crude fat samples. So these results indicated that isotope fractionation in the various tissue was discrepant. (authors)

Stable water isotopes suggest sub-canopy water recycling in a northern forested catchment

Science.gov (United States)

Mark B. Green; Bethany K. Laursen; John L. Campbell; Kevin J. McGuire; Eric P. Kelsey

2015-01-01

Stable water isotopes provide a means of tracing many hydrologic processes, including poorly understood dynamics like soil water interactions with the atmosphere. We present a four-year dataset of biweekly water isotope samples from eight fluxes and stores in a headwater catchment at the Hubbard Brook Experimental Forest, New Hampshire, USA. We use Dansgaard's...

Are Cross-National Differences in IQ Profiles Stable? A Comparison of Finnish and U.S. WAIS Norms

Science.gov (United States)

Roivainen, Eka

2013-01-01

To study the concept of national IQ profile, we compared U.S. and Finnish WAIS, WAIS-R, and WAIS III nonverbal and working memory subtest norms. The U.S. standardization samples had consistently higher scores on the Coding and Digit span subtests, while the Finnish samples had higher scores on the Block design subtest. No stable cross-national…

Tempered stable laws as random walk limits

OpenAIRE

Chakrabarty, Arijit; Meerschaert, Mark M.

2010-01-01

Stable laws can be tempered by modifying the L\\'evy measure to cool the probability of large jumps. Tempered stable laws retain their signature power law behavior at infinity, and infinite divisibility. This paper develops random walk models that converge to a tempered stable law under a triangular array scheme. Since tempered stable laws and processes are useful in statistical physics, these random walk models can provide a basic physical model for the underlying physical phenomena.

Producing air-stable monolayers of phosphorene and their defect engineering.

Science.gov (United States)

Pei, Jiajie; Gai, Xin; Yang, Jiong; Wang, Xibin; Yu, Zongfu; Choi, Duk-Yong; Luther-Davies, Barry; Lu, Yuerui

2016-01-22

It has been a long-standing challenge to produce air-stable few- or monolayer samples of phosphorene because thin phosphorene films degrade rapidly in ambient conditions. Here we demonstrate a new highly controllable method for fabricating high quality, air-stable phosphorene films with a designated number of layers ranging from a few down to monolayer. Our approach involves the use of oxygen plasma dry etching to thin down thick-exfoliated phosphorene flakes, layer by layer with atomic precision. Moreover, in a stabilized phosphorene monolayer, we were able to precisely engineer defects for the first time, which led to efficient emission of photons at new frequencies in the near infrared at room temperature. In addition, we demonstrate the use of an electrostatic gate to tune the photon emission from the defects in a monolayer phosphorene. This could lead to new electronic and optoelectronic devices, such as electrically tunable, broadband near infrared lighting devices operating at room temperature.

Preparation and characterization of stable aqueous higher-order fullerenes

International Nuclear Information System (INIS)

Aich, Nirupam; Flora, Joseph R V; Saleh, Navid B

2012-01-01

Stable aqueous suspensions of nC 60 and individual higher fullerenes, i.e. C 70 , C 76 and C 84 , are prepared by a calorimetric modification of a commonly used liquid–liquid extraction technique. The energy requirement for synthesis of higher fullerenes has been guided by molecular-scale interaction energy calculations. Solubilized fullerenes show crystalline behavior by exhibiting lattice fringes in high resolution transmission electron microscopy images. The fullerene colloidal suspensions thus prepared are stable with a narrow distribution of cluster radii (42.7 ± 0.8 nm, 46.0 ± 14.0 nm, 60 ± 3.2 nm and 56.3 ± 1.1 nm for nC 60 , nC 70 , nC 76 and nC 84 , respectively) as measured by time-resolved dynamic light scattering. The ζ-potential values for all fullerene samples showed negative surface potentials with similar magnitude ( − 38.6 ± 5.8 mV, − 39.1 ± 4.2 mV, − 38.9 ± 5.8 mV and − 41.7 ± 5.1 mV for nC 60 , nC 70 , nC 76 and nC 84 , respectively), which provide electrostatic stability to the colloidal clusters. This energy-based modified solubilization technique to produce stable aqueous fullerenes will likely aid in future studies focusing on better applicability, determination of colloidal properties, and understanding of environmental fate, transport and toxicity of higher-order fullerenes. (paper)

Magnesium stable isotope ecology using mammal tooth enamel

Science.gov (United States)

Martin, Jeremy E.; Vance, Derek; Balter, Vincent

2015-01-01

Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

Revealing the hidden structural phases of FeRh

Science.gov (United States)

Kim, Jinwoong; Ramesh, R.; Kioussis, Nicholas

2016-11-01

Ab initio electronic structure calculations reveal that tetragonal distortion has a dramatic effect on the relative stability of the various magnetic structures (C-, A-, G-, A'-AFM, and FM) of FeRh giving rise to a wide range of novel stable/metastable structures and magnetic phase transitions between these states. We predict that the cubic G-AFM structure, which was believed thus far to be the ground state, is metastable and that the tetragonally expanded G-AFM is the stable structure. The low energy barrier separating these states suggests phase coexistence at room temperature. We propose an A'-AFM phase to be the global ground state among all magnetic phases which arises from the strain-induced tuning of the exchange interactions. The results elucidate the underlying mechanism for the recent experimental findings of electric-field control of magnetic phase transition driven via tetragonal strain. The magnetic phase transitions open interesting prospects for exploiting strain engineering for the next-generation memory devices.

Stable Isotopes and Oral Tori in Greenlandic Norse and Inuit

DEFF Research Database (Denmark)

Baumann, M.; Lynnerup, N.; Scott, G. R.

2017-01-01

Palatine (PT) and mandibular torus (MT) have long been of interest to dental researchers and anthropologists, but their aetiology remains unresolved. Some combination of genetic and environmental factors influences their expression, but the relative role of each remains contentious. Previous...... research has shown that the Greenlandic Norse exhibit exceptionally high frequencies and pronounced expressions of PT and MT. In this regard, they are significantly different from genetically related medieval Scandinavian populations, so environmental factors have to be considered. An earlier study...... that estimated stable carbon and nitrogen isotope compositions for a Greenlandic Norse sample makes it possible to compare directly PT and MT expression with the relative degree of marine protein intake. For comparative purposes, parallel observations were made on a Greenlandic Inuit sample. Some researchers...

Regional and inter annual patterns of heavy metals, organochlorines and stable isotopes in narwhals (Monodon monoceros) from West Greenland

DEFF Research Database (Denmark)

Dietz, R.; Riget, F.; Hobson, K.A.

2004-01-01

Samples of 150 narwhals obtained in different years from two West Greenland areas, Avanersuaq and Uummannaq, were compared for concentrations of and regional differences in heavy metals and organochlorines and stable-carbon and nitrogen isotopes. Cadmium, Hg, and Se concentrations increased....../age composition of the data. PCB and DDT concentrations in West Greenland narwhals were half those found in East Greenland and Svalbard. Stable-carbon isotope ratios in muscle of 150 narwhals showed a decreasing trend in the first year when they gradually reduced their dependency on mother's milk, after which...... between stable isotope ratios and metal and OC concentrations....

Stable preparations of tyrosine hydroxylase provide the solution structure of the full-length enzyme

Science.gov (United States)

Bezem, Maria T.; Baumann, Anne; Skjærven, Lars; Meyer, Romain; Kursula, Petri; Martinez, Aurora; Flydal, Marte I.

2016-01-01

Tyrosine hydroxylase (TH) catalyzes the rate-limiting step in the biosynthesis of catecholamine neurotransmitters. TH is a highly complex enzyme at mechanistic, structural, and regulatory levels, and the preparation of kinetically and conformationally stable enzyme for structural characterization has been challenging. Here, we report on improved protocols for purification of recombinant human TH isoform 1 (TH1), which provide large amounts of pure, stable, active TH1 with an intact N-terminus. TH1 purified through fusion with a His-tagged maltose-binding protein on amylose resin was representative of the iron-bound functional enzyme, showing high activity and stabilization by the natural feedback inhibitor dopamine. TH1 purified through fusion with a His-tagged ZZ domain on TALON is remarkably stable, as it was partially inhibited by resin-derived cobalt. This more stable enzyme preparation provided high-quality small-angle X-ray scattering (SAXS) data and reliable structural models of full-length tetrameric TH1. The SAXS-derived model reveals an elongated conformation (Dmax = 20 nm) for TH1, different arrangement of the catalytic domains compared with the crystal structure of truncated forms, and an N-terminal region with an unstructured tail that hosts the phosphorylation sites and a separated Ala-rich helical motif that may have a role in regulation of TH by interacting with binding partners. PMID:27462005

Generalized q-sampling imaging fiber tractography reveals displacement and infiltration of fiber tracts in low-grade gliomas

Energy Technology Data Exchange (ETDEWEB)

Celtikci, Pinar; Fernandes-Cabral, David T.; Yeh, Fang-Cheng; Panesar, Sandip S.; Fernandez-Miranda, Juan C. [University of Pittsburgh Medical Center, Department of Neurological Surgery, Pittsburgh, PA (United States)

2018-03-15

Low-grade gliomas (LGGs) are slow growing brain tumors that often cause displacement and/or infiltration of the surrounding white matter pathways. Differentiation between infiltration and displacement of fiber tracts remains a challenge. Currently, there is no reliable noninvasive imaging method capable of revealing such white matter alteration patterns. We employed quantitative anisotropy (QA) derived from generalized q-sampling imaging (GQI) to identify patterns of fiber tract alterations by LGGs. Sixteen patients with a neuropathological diagnosis of LGG (WHO grade II) were enrolled. Peritumoral fiber tracts underwent qualitative and quantitative evaluation. Contralateral hemisphere counterparts were used for comparison. Tracts were qualitatively classified as unaffected, displaced, infiltrated or displaced, and infiltrated at once. The average QA of whole tract (W), peritumoral tract segment (S), and their ratio (S/W) were obtained and compared to the healthy side for quantitative evaluation. Qualitative analysis revealed 9 (13.8%) unaffected, 24 (36.9%) displaced, 13 (20%) infiltrated, and 19 (29.2%) tracts with a combination of displacement and infiltration. There were no disrupted tracts. There was a significant increase in S/W ratio among displaced tracts in the pre-operative scans in comparison with the contralateral side. QA values of peritumoral tract segments (S) were significantly lower in infiltrated tracts. WHO grade II LGGs might displace, infiltrate, or cause a combination of displacement and infiltration of WM tracts. QA derived from GQI provides valuable information that helps to differentiate infiltration from displacement. Anisotropy changes correlate with qualitative alterations, which may serve as a potential biomarker of fiber tract integrity. (orig.)

Characterization and antibacterial properties of stable silver substituted hydroxyapatite nanoparticles synthesized through surfactant assisted microwave process

Energy Technology Data Exchange (ETDEWEB)

Iqbal, Nida [Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Abdul Kadir, Mohammed Rafiq, E-mail: rafiq@biomedical.utm.my [Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Nik Malek, Nik Ahmad Nazim [Faculty of Bioscience and Medical Engineering (FBME), Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Mahmood, Nasrul Humaimi Bin [Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Murali, Malliga Raman; Kamarul, T. [Tissue Engineering Group, NOCERAL, Department of Orthopaedic Surgery, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2013-09-01

Highlights: • Stable nano sized silver substitute hydroxyapatite is prepared under surfactant assisted microwave process at 600 W power for 7 min. • The nanoparticles are in the size range of 58–72 nm and exert uniform elongated spheroid morphology. • Increase in silver concentration resulted in better dielectric properties. • Good antibacterial activity and silver release. - Abstract: The present study reports a relatively simple method for the synthesis of stable silver substituted hydroxyapatite nanoparticles with controlled morphology and particle size. In order to achieve this, CTAB is included as a surfactant in the microwave refluxing process (600 W for 7 min). The nanoparticles produced with different silver ion concentrations (0.05, 0.1 and 0.2 wt%) were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX) and Brunauer–Emmett–Teller (BET) analysis. XRD and FTIR analyses reveal that the Ag-HA nanoparticles were phase pure at 1000 °C. FESEM images showed that the produced nanoparticles are in the size range of 58–72 nm and exert uniform elongated spheroid morphology. The dielectric properties suggest that the increase in dielectric constant (ε′) and dissipation factor (D) values with increasing Ag concentrations. Antibacterial performance of the Ag-HA samples elucidated using disk diffusion technique (DDT) and minimum inhibitory concentration (MIC) demonstrates anti-bacterial activity against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli. This effect was dose dependent and was more pronounced against Gram-negative bacteria than Gram-positive organisms.

Characterization and antibacterial properties of stable silver substituted hydroxyapatite nanoparticles synthesized through surfactant assisted microwave process

International Nuclear Information System (INIS)

Iqbal, Nida; Abdul Kadir, Mohammed Rafiq; Nik Malek, Nik Ahmad Nazim; Mahmood, Nasrul Humaimi Bin; Murali, Malliga Raman; Kamarul, T.

2013-01-01

Highlights: • Stable nano sized silver substitute hydroxyapatite is prepared under surfactant assisted microwave process at 600 W power for 7 min. • The nanoparticles are in the size range of 58–72 nm and exert uniform elongated spheroid morphology. • Increase in silver concentration resulted in better dielectric properties. • Good antibacterial activity and silver release. - Abstract: The present study reports a relatively simple method for the synthesis of stable silver substituted hydroxyapatite nanoparticles with controlled morphology and particle size. In order to achieve this, CTAB is included as a surfactant in the microwave refluxing process (600 W for 7 min). The nanoparticles produced with different silver ion concentrations (0.05, 0.1 and 0.2 wt%) were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX) and Brunauer–Emmett–Teller (BET) analysis. XRD and FTIR analyses reveal that the Ag-HA nanoparticles were phase pure at 1000 °C. FESEM images showed that the produced nanoparticles are in the size range of 58–72 nm and exert uniform elongated spheroid morphology. The dielectric properties suggest that the increase in dielectric constant (ε′) and dissipation factor (D) values with increasing Ag concentrations. Antibacterial performance of the Ag-HA samples elucidated using disk diffusion technique (DDT) and minimum inhibitory concentration (MIC) demonstrates anti-bacterial activity against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli. This effect was dose dependent and was more pronounced against Gram-negative bacteria than Gram-positive organisms

Stable isotope signatures in bulk samples from two soils with contrasting characteristics. What do they tell about ongoing pedogenic processes?

Science.gov (United States)

Jiménez-Morillo, Nicasio T.; dos Anjos Leal, Otávio; Knicker, Heike; Pinheiro Dick, Deborah; González-Vila, Francisco J.; González-Pérez, José A.

2014-05-01

Isotopic ratio mass spectrometry (IRMS) has been proven as a promising tool for the monitoring of biogeochemical processes in soil. In this work, stable isotope signatures of light elements δ15N, δ13C, δ18O and δD were determined for two soils with contrasting characteristics in terms of climate, vegetation, land use and management. The studied soils were a Cambisol from a subtropical area (Paraná region, South Brazil) and an Arenosol from a Mediterranean climate (Andalusia, South Spain). A Flash 2000 HT (N, C, S, H and O) elemental analyzer (Thermo Scientific) coupled to a Delta V Advantage IRMS (Thermo Scientific) was used. Isotopic ratios are reported as parts per thousand (o ) deviations from appropriate standards recognized by the international atomic energy agency (IAEA). In a first approach we took advantage of the well-known different δ13C signature between plants using either the C4 or C3 carbon fixation pathway (O'Leary, 1981). The Arenosol (Spain) revealed a δ13C signature which is clearly in the range of C3 plants (-26 to -30 o ). Different plant canopies (tree, shrubs or ferns) caused only slight variations δ13C (STD= 0.98). In contrast, the Cambisol (Brazil) showed less depletion of the heavier carbon isotope corresponding to C4 predominant vegetation. In addition an increase from -19 o in the soil surface (0 - 5 cm) to -16 o in the subsoil (20 - 30 cm) was observed in line with a recent (2 years old) shift of the land use from the predominant C4 grassland to eucalypt (C3) cultivation. Crossplots of δ15N vs. δ18O may provide information about nitrate (NO3-) sources and N cycling (Kendall, 1998). In the Mediterranean Arenosol this signal (δ18O = 30o δ15N = 2o ) was found compatible with a predominant nitrate atmospheric deposition, whereas the signal in the Brazilian Cambisol pointed to the use of a mineral N fertilization with signs of denitrification processes (δ18O = 13o δ15N = 9o ). No conclusive results could be obtained from the �

Heavy element stable isotope ratios. Analytical approaches and applications

International Nuclear Information System (INIS)

Tanimizu, Masaharu; Sohrin, Yoshiki; Hirata, Takafumi

2013-01-01

Continuous developments in inorganic mass spectrometry techniques, including a combination of an inductively coupled plasma ion source and a magnetic sector-based mass spectrometer equipped with a multiple-collector array, have revolutionized the precision of isotope ratio measurements, and applications of inorganic mass spectrometry for biochemistry, geochemistry, and marine chemistry are beginning to appear on the horizon. Series of pioneering studies have revealed that natural stable isotope fractionations of many elements heavier than S (e.g., Fe, Cu, Zn, Sr, Ce, Nd, Mo, Cd, W, Tl, and U) are common on Earth, and it had been widely recognized that most physicochemical reactions or biochemical processes induce mass-dependent isotope fractionation. The variations in isotope ratios of the heavy elements can provide new insights into past and present biochemical and geochemical processes. To achieve this, the analytical community is actively solving problems such as spectral interference, mass discrimination drift, chemical separation and purification, and reduction of the contamination of analytes. This article describes data calibration and standardization protocols to allow interlaboratory comparisons or to maintain traceability of data, and basic principles of isotope fractionation in nature, together with high-selectivity and high-yield chemical separation and purification techniques for stable isotope studies.

Relation between distribution coefficient of radioactive strontium and solid-liquid distribution ratio of background stable strontium

International Nuclear Information System (INIS)

Igarashi, Toshifumi; Mahara, Yasunori; Okamura, Masaki; Ashikawa, Nobuo.

1992-01-01

Distribution coefficients (K d ) of nuclides, which are defined as the ratio of the adsorbed concentration to the solution concentration, are important in predicting nuclide migration in the subsurface environment. This study was undertaken to contrust an effective method of determining the most pertinent K d value for simulating in situ distribution phenomena between the solid and liquid phases, by using background stable isotopes. This paper describes the applicability of this method to Sr by carrying out a batch Sr adsorption experiment where stable Sr coexisted with the radioactive isotope, 85 Sr, and by comparing the concentration distribution ratio of the background stable Sr with the K d value obtained by the batch experiment. The results showed that the K d of 85 Sr (K d85 ) agreed well with the K d of the coexisting stable Sr (K ds ) and that the two values decreased with an increase in the concentration of the stable Sr, when sand was used as an adsorbent. In addition, the K d85 corresponded to the ratio of the exchangeable solid-phase concentration of background stable Sr to the concentration of the background stable Sr in groundwater when the concentration of the coexisting stable Sr approached the background level. On the other hand, when powdered rock samples were used, the K d85 did not agree with the K ds , and the concentration distribution ratio of the background stable Sr was greater than the K d85 . This discrepancy might be due to the disequilibrium resulting from grinding the rock matrices. This suggests that measurement of the background stable Sr distribution ratio between the solid and liquid phases can be an effective method of estimating the K d of radioactive Sr when the groundwater is in satisfactory contact with the adsorption medium. (author)

Improving Corrosion Behavior in SCWR, LFR and VHTR Reactor Materials by Formation of a Stable Oxide

International Nuclear Information System (INIS)

Motta, Arthur T.; Comstock, Robert; Li, Ning; Allen, Todd; Was, Gary

2009-01-01

The objective of this study is to understand the influence of the alloy microstructure and composition on the formation of a stable, protective oxide in the environments relevant to the SCWR and LFR reactor concepts, as well as to the VHTR. It is proposed to use state-of-the art techniques to study the fine structure of these oxides to identify the structural differences between stable and unstable oxide layers. The techniques to be used are microbeam synchrotron radiation diffraction and fluorescence, and cross-sectional transmission electron microcopy on samples prepared using focused ion beam.

ASSESSMENT OF AWARENESS LEVEL OF OWN DISEASE IN PATIENTS WITH STABLE ARTERIAL HYPERTENSION

Directory of Open Access Journals (Sweden)

G. F. Andreeva

2005-01-01

Full Text Available Arterial hypertension (AH is the most frequent risk factor of cardiovascular diseases and related mortality in all developed countries. Altough therapy with antihypertensive drugs significantly reduces this risk, patients with stable mild hypertension have poor compliance with the treatment. The reasons and levels of inadequacy of antihypertensive therapy in this group of patients are well-known.Aim. To evaluate the awareness level of own disease, adequacy of therapy only in those patients with stable mild arterial hypertension, who are complied with recommendations of physicians concerning AH treatment and changing of mode of life. It was also planned to reveal possible grounds for inadequate secondary prevention of cardiovascular disease.Materials and methods. 76 patiens with stable mild arterial hypertension were included into study. They didn’t have any serious concomitant diseases and were complied with the recommendations of physicians concerning secondary prevention of cardiovascular disease. Questionnaire of State Research Center for Preventive Medicine “Assessment of awareness level of own disease in patients with stable arterial hypertension” was used in the study.Results. It was revealed, that the majority of patients, invoved in the study, were nonsmokers and regularly took antihypertensive drugs. 70% of questioned patients reached the target arterial blood pressure levels, while patients with arterial hypertension in general Russia population received regular and efficient treatment in less than 30-20%. Drugs treatment of questioned patients almost didn’t differ from that, which received patients in out-patient clinics of Moscow: in both cases ACE inhibitors were preferred. Only 29% of questioned patients knew their lipid levels in blood and none of the patients took drugs, reducing levels of lipids in blood. Half of the patients, that took part in our study, had increased level of body mass index.Conclusions. Inadequate

Temperature and Humidity Control in Livestock Stables

DEFF Research Database (Denmark)

Hansen, Michael; Andersen, Palle; Nielsen, Kirsten M.

2010-01-01

The paper describes temperature and humidity control of a livestock stable. It is important to have a correct air flow pattern in the livestock stable in order to achieve proper temperature and humidity control as well as to avoid draught. In the investigated livestock stable the air flow...

Stable carbon isotope fractionation during the biodegradation of lambda-cyhalothrin.

Science.gov (United States)

Shen, Xiaoli; Xu, Zemin; Zhang, Xichang; Yang, Fangxing

2015-11-01

In this study, the microbial degradation of lambda-cyhalothrin in soil was investigated using compound-specific stable isotope analysis. The results revealed that lambda-cyhalothrin was biodegraded in soil under laboratory conditions. The half-lives of lambda-cyhalothrin were determined to be 49 and 161 days in non-sterile and sterile soils spiked with 2mg/kg lambda-cyhalothrin and 84 and 154 days in non-sterile and sterile soils spiked with 10mg/kg lambda-cyhalothrin, respectively. The biodegradation of lambda-cyhalothrin resulted in carbon isotope fractionation, which shifted from -29.0‰ to -26.5‰ in soil spiked with 2mg/kg lambda-cyhalothrin, and to -27.5‰ with 10mg/kg lambda-cyhalothrin. A relationship was established between the stable carbon isotope fraction and the residual concentrations of lambda-cyhalothrin by the Rayleigh equation in which the carbon isotope enrichment factor ε of the microbial degradation of lambda-cyhalothrin in the soil was calculated as -2.53‰. This study provides an approach to quantitatively evaluate the biodegradation of lambda-cyhalothrin in soil in field studies. Copyright © 2015 Elsevier B.V. All rights reserved.

Stable isotope variation as a tool to trace the authenticity of beef

International Nuclear Information System (INIS)

Boner, M.; Foerstel, H.

2004-01-01

Organic beef coming principally from Germany was analysed for the hydrogen, carbon, oxygen, nitrogen and sulfur stable isotopic composition to test the possibility of tracing back the geographical origin. Since there is a well-known pattern of D/H and 18 O/ 16 O in meteoric water and in ground water, there is an existing link to tissue water in the beef. By including the stable isotope ratios of the other elements of life further information is available: soils show different isotope ratios of 15 N/ 14 N and 34 S/ 32 S depending on the geological composition, cultivation and atmospheric sulfur deposition. As organic farming is mainly obliged to use only their produced fodder, that ratio is reflected in the beef as well. Different organic beef samples from various German farms have been collected and analysed over nearly two years. To check the differentiation of foreign beef, samples from Argentina and Chile were also included in the study. The analyses of meat samples indicate that it is possible to trace back the region (e.g. Argentina and Germany) by using isotopes of oxygen and hydrogen. A local geographical differentiation can be done by using the stable isotopes of nitrogen and sulfur, as was demonstrated for three farms in Colonia Bay. An optimal differentiation also depends on the quality of further information (e.g. the season, kind of cattle breeding or the declaration of the local geographical origin). Certainly authenticity of beef is not only linked with the geographical origin but can also reflect the differentiation of organic and conventional farming. The fodder of organic cattle farming consists mainly of C 3 plants and the use of C 4 plants is more usual in conventional cattle farming. A 13 C/ 12 C ratio above -20 permille appears as a limit for organic farming. Increased values have to be controlled based on their authenticity. (orig.)

The Myopic Stable Set for Social Environments

NARCIS (Netherlands)

Demuynck, Thomas; Herings, P. Jean-Jacques; Saulle, Riccardo; Seel, Christian

2017-01-01

We introduce a new solution concept for models of coalition formation, called the myopic stable set. The myopic stable set is defined for a very general class of social environments and allows for an infinite state space. We show that the myopic stable set exists and is non-empty. Under minor

Stable isotope analysis in primatology: a critical review.

Science.gov (United States)

Sandberg, Paul A; Loudon, James E; Sponheimer, Matt

2012-11-01

Stable isotope analysis has become an important tool in ecology over the last 25 years. A wealth of ecological information is stored in animal tissues in the relative abundances of the stable isotopes of several elements, particularly carbon and nitrogen, because these isotopes navigate through ecological processes in predictable ways. Stable carbon and nitrogen isotopes have been measured in most primate taxonomic groups and have yielded information about dietary content, dietary variability, and habitat use. Stable isotopes have recently proven useful for addressing more fine-grained questions about niche dynamics and anthropogenic effects on feeding ecology. Here, we discuss stable carbon and nitrogen isotope systematics and critically review the published stable carbon and nitrogen isotope data for modern primates with a focus on the problems and prospects for future stable isotope applications in primatology. © 2012 Wiley Periodicals, Inc.

Stable and selective self-assembly of α-lipoic acid on Ge(001) for biomolecule immobilization

Science.gov (United States)

Kazmierczak, M.; Flesch, J.; Mitzloff, J.; Capellini, G.; Klesse, W. M.; Skibitzki, O.; You, C.; Bettenhausen, M.; Witzigmann, B.; Piehler, J.; Schroeder, T.; Guha, S.

2018-05-01

We demonstrate a novel method for the stable and selective surface functionalization of germanium (Ge) embedded in silicon dioxide. The Ge(001) surface is functionalized using α-lipoic acid (ALA), which can potentially be utilized for the immobilization of a wide range of biomolecules. We present a detailed pH-dependence study to establish the effect of the incubation pH value on the adsorption layer of the ALA molecules. A threshold pH value for functionalization is identified, dividing the examined pH range into two regions. Below a pH value of 7, the formation of a disordered ALA multilayer is observed, whereas a stable well-ordered ALA mono- to bi-layer on Ge(001) is achieved at higher pH values. Furthermore, we analyze the stability of the ALA layer under ambient conditions, revealing the most stable functionalized Ge(001) surface to effectively resist oxidation for up to one week. Our established functionalization method paves the way towards the successful immobilization of biomolecules in future Ge-based biosensors.

Stable isotope measurements of atmospheric CO2

International Nuclear Information System (INIS)

White, J.W.C.; Ferretti, D.F.; Vaughn, B.H.; Francey, R.J.; Allison, C.E.

2002-01-01

The measurement of stable carbon isotope ratios of atmospheric carbon dioxide, δ 13 CO 2 are useful for partitioning surface-atmospheric fluxes into terrestrial and oceanic components. δC 18 OO also has potential for segregating photosynthetic and respiratory fluxes in terrestrial ecosystems. Here we describe in detail the techniques for making these measurements. The primary challenge for all of the techniques used to measure isotopes of atmospheric CO 2 is to achieve acceptable accuracy and precision and to maintain them over the decades needed to observe carbon cycle variability. The keys to success such an approach are diligent intercalibrations of laboratories from around the world, as well as the use of multiple techniques such as dual inlet and GC-IRMS and the intercomparison of such measurements. We focus here on two laboratories, the Stable Isotope Lab at the Institute for Arctic and Alpine Research (INSTAAR) at the University of Colorado is described and the Commonwealth Scientific and Industrial Research Organisation - Atmospheric Research (CSIRO). Different approaches exist at other laboratories (e.g. programs operated by Scripps Institution of Oceanography (SIO) and The Center for Atmospheric and Oceanic Studies, Toboku University (TU)) however these are not discussed here. Finally, we also discuss the recently developed Gas Chromatography - Isotope Ratio Mass Spectrometry (GC-IRMS) technique which holds significant promise for measuring ultra-small samples of gas with good precision. (author)

Statistical sampling strategies

International Nuclear Information System (INIS)

Andres, T.H.

1987-01-01

Systems assessment codes use mathematical models to simulate natural and engineered systems. Probabilistic systems assessment codes carry out multiple simulations to reveal the uncertainty in values of output variables due to uncertainty in the values of the model parameters. In this paper, methods are described for sampling sets of parameter values to be used in a probabilistic systems assessment code. Three Monte Carlo parameter selection methods are discussed: simple random sampling, Latin hypercube sampling, and sampling using two-level orthogonal arrays. Three post-selection transformations are also described: truncation, importance transformation, and discretization. Advantages and disadvantages of each method are summarized

Stable cycling in discrete-time genetic models.

OpenAIRE

Hastings, A

1981-01-01

Examples of stable cycling are discussed for two-locus, two-allele, deterministic, discrete-time models with constant fitnesses. The cases that cycle were found by using numerical techniques to search for stable Hopf bifurcations. One consequence of the results is that apparent cases of directional selection may be due to stable cycling.

Stable cycling in discrete-time genetic models.

Science.gov (United States)

Hastings, A

1981-11-01

Examples of stable cycling are discussed for two-locus, two-allele, deterministic, discrete-time models with constant fitnesses. The cases that cycle were found by using numerical techniques to search for stable Hopf bifurcations. One consequence of the results is that apparent cases of directional selection may be due to stable cycling.

Design and construction of an oscillator with a higly stable frequency

International Nuclear Information System (INIS)

Jardon, A.H.

1978-01-01

An instrument producing pulses with a highly stable frequency was considered necessary for time measurement at the INEN Plasma Physics Program. For this purpose an oscillator with a higly stable frequency which is a measurement instrument was designed and constructed since it can be used as a reference for the measurement of frequency, time, length and phase. The parameters required for this oscillator were as follows: aging lesser than 1 part/10 9 , for sampling period of 0.1 sec.; frequency change equal or smaller than 1 part/10 9 for normal temperature fluctuations found in the laboratory (10 0 C-30 0 C); frequency 1 MHz; amplitude 2 V. After the oscillator was built the parameters were not verified and therefore its characteristics are not exactly known; the reported partial results show that the approximations used for the design are generally valid. (author)

Stable beams

CERN Multimedia

2015-01-01

Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

MALDI-based identification of stable hazelnut protein derived tryptic marker peptides.

Science.gov (United States)

Cucu, T; De Meulenaer, B; Devreese, B

2012-01-01

Food allergy is an important health problem especially in industrialised countries. Tree nuts, among which are hazelnuts (Corylus avellana), are typically causing serious and life-threatening symptoms in sensitive subjects. Hazelnut is used as a food ingredient in pastry, confectionary products, ice cream and meat products, therefore undeclared hazelnut can be often present as a cross-contaminant representing a threat for allergic consumers. Mass spectrometric techniques are used for the detection of food allergens in processed foods, but limited information regarding stable tryptic peptide markers for hazelnut is available. The aim of this study was to detect stable peptide markers from modified hazelnut protein through the Maillard reaction and oxidation in a buffered solution. Peptides ³⁹⁵Gly-Arg⁴⁰³ from Cor a 11 and ²⁰⁹Gln-Arg²¹⁷, ³⁵¹Ile-Arg³⁶³, ⁴⁶⁴Ala-Arg⁴⁷⁸ and ⁴⁰¹Val-Arg⁴¹⁷ from Cor a 9 hazelnut allergens proved to be the most stable and could be detected and confirmed with high scores in most of the modified samples. The identified peptides can be further used as analytical targets for the development of more robust quantitative methods for hazelnut detection in processed foods.

Stable Isotopic Analysis on Water Utilization of Two Xerophytic Shrubs in a Revegetated Desert Area: Tengger Desert, China

OpenAIRE

Lei Huang; Zhishan Zhang

2015-01-01

Stable isotope studies on stable isotope ratios of hydrogen and oxygen in water within plants provide new information on water sources and water use patterns under natural conditions. In this study, the sources of water uptake for two typical xerophytic shrubs, Caragana korshinskii and Artemisia ordosica, were determined at four different-aged revegetated sites (1956, 1964, 1981, and 1987) in the Tengger Desert, a revegetated desert area in China. Samples from precipitation, soil water at dif...

Selecting the best stable isotope mixing model to estimate grizzly bear diets in the Greater Yellowstone Ecosystem.

Directory of Open Access Journals (Sweden)

John B Hopkins

Full Text Available Past research indicates that whitebark pine seeds are a critical food source for Threatened grizzly bears (Ursus arctos in the Greater Yellowstone Ecosystem (GYE. In recent decades, whitebark pine forests have declined markedly due to pine beetle infestation, invasive blister rust, and landscape-level fires. To date, no study has reliably estimated the contribution of whitebark pine seeds to the diets of grizzlies through time. We used stable isotope ratios (expressed as δ13C, δ15N, and δ34S values measured in grizzly bear hair and their major food sources to estimate the diets of grizzlies sampled in Cooke City Basin, Montana. We found that stable isotope mixing models that included different combinations of stable isotope values for bears and their foods generated similar proportional dietary contributions. Estimates generated by our top model suggest that whitebark pine seeds (35±10% and other plant foods (56±10% were more important than meat (9±8% to grizzly bears sampled in the study area. Stable isotope values measured in bear hair collected elsewhere in the GYE and North America support our conclusions about plant-based foraging. We recommend that researchers consider model selection when estimating the diets of animals using stable isotope mixing models. We also urge researchers to use the new statistical framework described here to estimate the dietary responses of grizzlies to declines in whitebark pine seeds and other important food sources through time in the GYE (e.g., cutthroat trout, as such information could be useful in predicting how the population will adapt to future environmental change.

Verification of Egg Farming Systems from The Netherlands and New Zealand Using Stable Isotopes.

Science.gov (United States)

Rogers, Karyne M; van Ruth, Saskia; Alewijn, Martin; Philips, Andy; Rogers, Pam

2015-09-30

Stable isotopes were used to develop authentication criteria of eggs laid under cage, barn, free range, and organic farming regimens from The Netherlands and New Zealand. A training set of commercial poultry feeds and egg albumen from 49 poultry farms across The Netherlands was used to determine the isotopic variability of organic and conventional feeds and to assess trophic effects of these corresponding feeds and barn, free range, and organic farming regimens on corresponding egg albumen. A further 52 brands of New Zealand eggs were sampled from supermarket shelves in 2008 (18), 2010 (30), and 2014 (4) to characterize and monitor changes in caged, barn, free range, and organic egg farming regimens. Stable carbon (δ(13)C) and nitrogen (δ(15)N) isotopes of 49 commercial poultry feeds and their corresponding egg albumens reveals that Dutch poultry are fed exclusively on a plant-based feed and that it is possible to discriminate between conventional and organic egg farming regimens in The Netherlands. Similarly, it is possible to discriminate between New Zealand organic and conventional egg farming regimens, although in the initial screening in 2008, results showed that some organic eggs had isotope values similar to those of conventional eggs, suggesting hens were not exclusively receiving an organic diet. Dutch and New Zealand egg regimens were shown to have a low isotopic correlation between both countries, because of different poultry feed compositions. In New Zealand, both conventional and organic egg whites have higher δ(15)N values than corresponding Dutch egg whites, due to the use of fishmeal or meat and bone meal (MBM), which is banned in European countries. This study suggests that stable isotopes (specifically nitrogen) show particular promise as a screening and authentication tool for organically farmed eggs. Criteria to assess truthfulness in labeling of organic eggs were developed, and we propose that Dutch organic egg whites should have a minimum �

Grasland Stable Isotope Flux Measurements: Three Isotopomers of Carbon Dioxide Measured by QCL Spectroscopy

Science.gov (United States)

Zeeman, M. J.; Tuzson, B.; Eugster, W.; Werner, R. A.; Buchmann, N.; Emmenegger, L.

2007-12-01

To improve our understanding of greenhouse gas dynamics of managed ecosystems such as grasslands, we not only need to investigate the effects of management (e.g., grass cuts) and weather events (e.g., rainy days) on carbon dioxide fluxes, but also need to increase the time resolution of our measurements. Thus, for the first time, we assessed respiration and assimilation fluxes with high time resolution (5Hz) stable isotope measurements at an intensively managed farmland in Switzerland (Chamau, 400m ASL). Two different methods were used to quantify fluxes of carbon dioxide and associated fluxes of stable carbon isotopes: (1) the flux gradient method, and (2) the eddy covariance method. During a week long intensive measurement campaign, we (1) measured mixing ratios of carbon dioxide isotopomers (12C16O2, 12C16O18O, 13C16O2) with a Quantum Cascade Laser (QCL, Aerodyne Inc.) spectroscope and (2) collected air samples for isotope analyses (13C/12C) and (18O/16O) of carbon dioxide by Isotope Ratio Mass Spectrometry (IRMS, Finnigan) every two hours, concurrently along a height profile (z = 0.05; 0.10; 0.31; 2.15m). In the following week, the QCL setup was used for closed-path eddy covariance flux measurement of the carbon dioxide isotopomers, with the air inlet located next to an open-path Infra Red Gas Analyzers (IRGA, LiCor 7500) used simultaneously for carbon dioxide measurements. During this second week, an area of grass inside the footprint was cut and harvested after several days. The first results of in-field continuous QCL measurements of carbon dioxide mixing ratios and their stable isotopic ratios show good agreement with IRGA measurements and isotope analysis of flask samples by IRMS. Thus, QCL spectroscopy is a very promising tool for stable isotope flux investigations.

Radiocarbon variability of fatty acids in semi-urban aerosol samples

International Nuclear Information System (INIS)

Matsumoto, Kohei; Uchida, Masao; Kawamura, Kimitaka; Shibata, Yasuyuki; Morita, Masatoshi

2004-01-01

We analyzed radiocarbon and the stable carbon isotope ratio for individual monocarboxylic (fatty) acids in an aerosol sample (QFF 2138) and compared the results with data of the aerosol sample taken in another year. The fatty acid concentration distribution of aerosol sample QFF 2138 showed a bimodal pattern with maxima at C 16 and C 26 . Stable carbon isotope ratios of the fatty acids ranged from -30.8 per mille to -23.0 per mille which indicates the animal and/or marine algae origins for C 16 -C 19 fatty acids and mainly terrestrial C 3 plant origins for C >20 fatty acids. Δ 14 C values for fatty acids ranged from -89.7 per mille to +83.5 per mille. Compared with QFF1969, we found that the Δ 14 C values of fatty acids exhibited a wide diversity and Δ 14 C values for each fatty acid in QFF 2138 were largely different from those of QFF 1969

Effectiveness and risks of stable iodine prophylaxis

International Nuclear Information System (INIS)

Waight, P.J.

1995-01-01

The factors upon which the efficacy of stable iodine prophylaxis depends are reviewed, with particular reference to the dose of stable iodine, the timing of the dose, the influence of dietary iodine and the impact of the other prospective actions. The risks of stable iodine ingestion are estimated, and their application to the principle of Justification in outlined. (Author)

Feeding preferences of West Indian manatees in Florida, Belize, and Puerto Rico as indicated by stable isotope analysis

Science.gov (United States)

Alves-Stanley, Christy D.; Worthy, Graham A.J.; Bonde, Robert K.

2010-01-01

The endangered West Indian manatee Trichechus manatus has 2 recognized subspecies: the Florida T. m. latirostris and Antillean T. m. manatus manatee, both of which are found in freshwater, estuarine, and marine habitats. A better understanding of manatee feeding preferences and habitat use is essential to establish criteria on which conservation plans can be based. Skin from manatees in Florida, Belize, and Puerto Rico, as well as aquatic vegetation from their presumed diet, were analyzed for stable carbon and nitrogen isotope ratios. This is the first application of stable isotope analysis to Antillean manatees. Stable isotope ratios for aquatic vegetation differed by plant type (freshwater, estuarine, and marine), collection location, and in one instance, season. Carbon and nitrogen isotope ratios for manatee skin differed between collection location and in one instance, season, but did not differ between sex or age class. Signatures in the skin of manatees sampled in Belize and Puerto Rico indicated a diet composed primarily of seagrasses, whereas those of Florida manatees exhibited greater regional variation. Mixing model results indicated that manatees sampled from Crystal River and Homosassa Springs (Florida, USA) ate primarily freshwater vegetation, whereas manatees sampled from Big Bend Power Plant, Ten Thousand Islands, and Warm Mineral Springs (Florida) fed primarily on seagrasses. Possible diet-tissue discrimination values for 15N were estimated to range from 1.0 to 1.5 per mil. Stable isotope analysis can be used to interpret manatee feeding behavior over a long period of time, specifically the use of freshwater vegetation versus seagrasses, and can aid in identifying critical habitats and improving conservation efforts.

Ballooning stable high beta tokamak equilibria

International Nuclear Information System (INIS)

Tuda, Takashi; Azumi, Masafumi; Kurita, Gen-ichi; Takizuka, Tomonori; Takeda, Tatsuoki

1981-04-01

The second stable regime of ballooning modes is numerically studied by using the two-dimensional tokamak transport code with the ballooning stability code. Using the simple FCT heating scheme, we find that the plasma can locally enter this second stable regime. And we obtained equilibria with fairly high beta (β -- 23%) stable against ballooning modes in a whole plasma region, by taking into account of finite thermal diffusion due to unstable ballooning modes. These results show that a tokamak fusion reactor can operate in a high beta state, which is economically favourable. (author)

Generation of Phase-Stable Sub-Cycle Mid-Infrared Pulses from Filamentation in Nitrogen

Directory of Open Access Journals (Sweden)

Takao Fuji

2013-02-01

Full Text Available Sub-single-cycle pulses in the mid-infrared (MIR region were generated through a laser-induced filament. The fundamental (ω1 and second harmonic (ω2 output of a 30-fs Ti:sapphire amplifier were focused into nitrogen gas and produce phase-stable broadband MIR pulses (ω0 by using a four-wave mixing process (ω1 + ω1 - ω2 → ω0 through filamentation. The spectrum spread from 400 cm-1 to 5500 cm-1, which completely covered the MIR region. The low frequency components were detected by using an electro-optic sampling technique with a gaseous medium. The efficiency of the MIR pulse generation was very sensitive to the delay between the fundamental and second harmonic pulses. It was revealed that the delay dependence of the efficiency came from the interference between two opposite parametric processes, ω1 + ω1 - ω2 → ω0 and ω2 - ω1 - ω1 → ω0. The pulse duration was measured as 6.9 fs with cross-correlation frequency-resolved optical gating by using four-wave mixing in nitrogen. The carrier-envelope phase of the MIR pulse was passively stabilized. The instability was estimated as 154 mrad rms in 2.5 h.

Using stable isotopes of carbon and nitrogen as in-situ tracers for monitoring the natural attenuation of explosives

National Research Council Canada - National Science Library

Miyares, Paul H

1999-01-01

The use of carbon and nitrogen stable isotope measurements from TNT was examined as a possible tool for monitoring the natural attenuation of TNT incubation studies of spiked soil samples were conducted...

Habitat use and trophic position effects on contaminant bioaccumulation in fish indicated by stable isotope composition

Science.gov (United States)

The objective of our study was to determine the relationship between fish tissue stable isotope composition and total mercury or polychlorinated biphenyl (PCB) concentrations in a Great Lakes coastal food web. We sampled two resident fishes, Yellow Perch (Perca flavescens) and Bl...

Fecal steroid hormones reveal reproductive state in female blue whales sampled in the Gulf of California, Mexico.

Science.gov (United States)

Valenzuela-Molina, Marcia; Atkinson, Shannon; Mashburn, Kendall; Gendron, Diane; Brownell, Robert L

2018-05-15

Steroid hormone assessment using non-invasive sample collection techniques can reveal the reproductive status of aquatic mammals and the physiological mechanisms by which they respond to changes in their environment. A portion of the eastern North Pacific blue whale (Balaenoptera musculus) population that seasonally visits the Gulf of California, Mexico has been monitored using photo-identified individuals for over 30 years. The whales use the area in winter-early spring for nursing their calves and feeding and it therefore is well suited for fecal sample collection. Using radioimmunoassays in 25 fecal samples collected between 2009 and 2012 to determine reproductive state and stress, we validated three steroid hormones (progesterone, corticosterone and cortisol) in adult female blue whales. Females that were categorized as pregnant had higher mean fecal progesterone metabolite concentrations (1292.6 ± 415.6 ng·g -1 ) than resting and lactating females (14.0 ± 3.7 ng·g -1 ; 23.0 ± 5.4 ng·g -1 , respectively). Females classified as pregnant also had higher concentrations of corticosterone metabolites (37.5 ± 9.9 ng·g -1 ) than resting and lactating females (17.4 ± 2.0 ng·g -1 ; 16.8 ± 2.8 ng·g -1 , respectively). In contrast, cortisol metabolite concentrations showed high variability between groups and no significant relationship to reproductive state. We successfully determined preliminary baseline parameters of key steroid hormones by reproductive state in adult female blue whales. The presence of pregnant or with luteal activity and known lactating females confirms that the Gulf of California is an important winter-spring area for the reproductive phase of these blue whales. The baseline corticosterone levels we are developing will be useful for assessing the impact of the increasing coastal development and whale-watching activities on the whales in the Gulf of California. Copyright © 2018 Elsevier Inc. All

Multi-scale sampling to evaluate assemblage dynamics in an oceanic marine reserve.

Directory of Open Access Journals (Sweden)

Andrew R Thompson

Full Text Available To resolve the capacity of Marine Protected Areas (MPA to enhance fish productivity it is first necessary to understand how environmental conditions affect the distribution and abundance of fishes independent of potential reserve effects. Baseline fish production was examined from 2002-2004 through ichthyoplankton sampling in a large (10,878 km(2 Southern Californian oceanic marine reserve, the Cowcod Conservation Area (CCA that was established in 2001, and the Southern California Bight as a whole (238,000 km(2 CalCOFI sampling domain. The CCA assemblage changed through time as the importance of oceanic-pelagic species decreased between 2002 (La Niña and 2003 (El Niño and then increased in 2004 (El Niño, while oceanic species and rockfishes displayed the opposite pattern. By contrast, the CalCOFI assemblage was relatively stable through time. Depth, temperature, and zooplankton explained more of the variability in assemblage structure at the CalCOFI scale than they did at the CCA scale. CalCOFI sampling revealed that oceanic species impinged upon the CCA between 2002 and 2003 in association with warmer offshore waters, thus explaining the increased influence of these species in the CCA during the El Nino years. Multi-scale, spatially explicit sampling and analysis was necessary to interpret assemblage dynamics in the CCA and likely will be needed to evaluate other focal oceanic marine reserves throughout the world.

Characteristics of chemistry and stable isotopes in groundwater of the Chaobai River catchment, Beijing

Energy Technology Data Exchange (ETDEWEB)

Li, J. [Key Laboratory of Engineering Geomechanics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, J.; Wang, X. [Hydrogeology and Engineering Geology Team of Beijing, Beijing 100037 (China); Pang, Z. [Key Laboratory of Engineering Geomechanics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China)

2013-07-01

Environmental isotopes and chemical compositions are useful tools for the study of groundwater flow systems. Groundwater of the Chaobai River catchment, Beijing was sampled for chemical and stable isotopes analyses in 2005. Geochemical signatures evolve progressively from CaMg-HCO{sub 3} to NaK-HCO{sub 3}, and then to Na-HCO{sub 3} compositions as groundwater flows from the mountain to discharge areas. Groundwater can be divided into two groups on the basis of stable isotope compositions: ancient groundwater and modern groundwater. Modern groundwater (-9.90/00 to -6.60/00 for δ{sup 18}O) plots along a line with a slope of 4.0 on a δ{sup 2}H versus δ{sup 18}O diagram, reflecting evaporation during the process of recharge, whereas ancient groundwater samples (30 to 12 Ka.) are different in isotopic composition (-11.00/00 and -68.20/00 for δ{sup 18}O and δ{sup 2}H, respectively), reflecting the cold and arid climate in the last glacial period. The results have important implications for groundwater management in Beijing City. (authors)

Stable isotope ratio measurements in hydrogen, nitrogen, and oxygen using Raman scattering

International Nuclear Information System (INIS)

Harney, R.C.; Bloom, S.D.; Milanovich, F.P.

1975-01-01

A method for measuring stable isotope ratios using laser Raman scattering was developed which may prove of significant utility and benefit in stable isotope tracer studies. Crude isotope ratio measurements obtained with a low-power laser indicate that with current technology it should be possible to construct an isotope ratio measurement system using laser Raman scattering that is capable of performing 0.1 percent accuracy isotope ratio measurements of 16 O/ 18 O in natural abundance oxygen gas or 14 N/ 15 N in natural abundance nitrogen gas in times less than two minutes per sample. Theory pertinent to the technique, designs of specific isotope ratio spectrometer systems, and data relating to isotope ratio measurements in hydrogen, nitrogen, and oxygen are presented. In addition, the current status of several studies utilizing this technique is discussed. (auth)

Somatic Cells in Bulk Samples and Purchase Prices of Cow Milk

Directory of Open Access Journals (Sweden)

Jindřich Kvapilík

2017-01-01

Full Text Available There were calculated the somatic cell count (SCC 209 (36 – 468 103ml–1, the total count of microorganisms (TCM 25 103ml–1 (from 5 to 377, fat 3.84 % (from 3.23 to 4.46 and protein content 3.39 % (from 3.04 to 3.75 and milk freezing point (MFP –0.525 °C (from –0.534 to –0.395 of the 522 monthly bulk milk samples from 11 experimental stables during the period from 2012 to 2015. Residues of inhibitory substances were not detected in any sample. Milk sale reached 7,999 liters (l with fluctuating between 6,150 and 10,532 l per cow. This can be deduced from the regression coefficients that due to increase in the SCC by 100 103ml–1 the TCM increased by 2.9 to 4.2 103ml–1, the fat content decreased by 0.09 to 0.13 % and protein about 0.01 to 0.05 %. Influence of SCC, TCM and the fat and protein content calculated from monthly samples for individual stables can be estimated at –0.12 CZC, fluctuations between the stables at +0.46 to –0.84 CZC per l of milk. The increase in milk price by 0.17 CZC in the range of –0.92 to +0.92 CZC per l of milk corresponds to averages of indicators calculated from 522 samples.

Quantification of isotope-labelled and unlabelled folates in plasma, ileostomy and food samples.

Science.gov (United States)

Büttner, Barbara E; Öhrvik, Veronica E; Witthöft, Cornelia M; Rychlik, Michael

2011-01-01

New stable isotope dilution assays were developed for the simultaneous quantitation of [(13)C(5)]-labelled and unlabelled 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid, folic acid along with unlabelled tetrahydrofolic acid and 10-formylfolic acid in clinical samples deriving from human bioavailability studies, i.e. plasma, ileostomy samples, and food. The methods were based on clean-up by strong anion exchange followed by LC-MS/MS detection. Deuterated analogues of the folates were applied as the internal standards in the stable isotope dilution assays. Assay sensitivity was sufficient to detect all relevant folates in the respective samples as their limits of detection were below 0.62 nmol/L in plasma and below 0.73 μg/100 g in food or ileostomy samples. Quantification of the [(13)C(5)]-label in clinical samples offers the possibility to differentiate between folate from endogenous body pools and the administered dose when executing bioavailability trials.

Facile synthesis of high-temperature (1000 °C) phase-stable rice-like anatase TiO2 nanocrystals

Science.gov (United States)

Lv, Lizhen; Chen, Qirong; Liu, Xiuyun; Wang, Miaomiao; Meng, Xiangfu

2015-05-01

High-temperature phase-stable rice-like anatase TiO2 nanocrystals were synthesized by one-pot solvothermal method using soluble titania xerogel and isopropyl alcohol (IPA) as the precursor and the solvent, respectively. Sample characterization was carried out by powder X-ray diffraction, high-resolution transmission electron microscopy, field emission scanning electron microscope, X-ray photoelectron spectroscopy, and N2 adsorption-desorption isotherms. The results showed that TiO2 nanocrystals had rice-like shapes with an average size of 5 nm in width and 35 nm in length. The BET surface area was 153 m2/g. Unexpectedly, the rice-like TiO2 nanocrystals exhibited high-temperature phase stability, which could remain as pure anatase phase after calcinations at 1000 °C. Growth mechanism investigation revealed that the IPA solvent played a key role in nucleation and growth of rice-like anatase TiO2 nanocrystals. The photodegradation of rhodamine B demonstrated that rice-like anatase TiO2 nanocrystals exhibited enhanced photocatalytic activity under visible light irradiation.

Identification of metabolically active methanogens in anaerobic digester by DNA Stable-Isotope Probing using 13C-acetate

Directory of Open Access Journals (Sweden)

V. Gowdaman

2015-04-01

Full Text Available Anaerobic digestion is gaining enormous attention due to the ability to covert organic wastes into biogas, an alternative sustainable energy. Methanogenic community plays a significant role in biogas production and also for proficient functioning of the anaerobic digester. Therefore, this study was carried out to investigate the methanogen diversity of a food waste anaerobic digester. After endogenous respiration, the digester samples were supplemented with isotopes of acetate to enrich methanogen population, and were analyzed using DNA-SIP (Stable-Isotope Probing. Following separation and fractionation of heavy (13C and light (12C DNA, PCR amplification was carried out using archaeal 16S rRNA gene followed by DGGE analysis. Sequencing of the prominent DGGE bands revealed the dominance of Methanocorpusculum labreanum species belonging to hydrogenotrophic Methanomicrobiales, which can produce methane in the presence of H2/CO2 and requires acetate for its growth. This is the first instance where Methanocorpusculum labreanum is being reported as a dominant species in an anaerobic digester operative on food waste.

Environmental controls on stable isotopes of precipitation in Lanzhou, China: An enhanced network at city scale.

Science.gov (United States)

Chen, Fenli; Zhang, Mingjun; Wang, Shengjie; Qiu, Xue; Du, Mingxia

2017-12-31

Stable hydrogen and oxygen isotopes in precipitation are very sensitive to environmental changes, and can record evolution of water cycle. The Lanzhou city in northwestern China is jointly influenced by the monsoon and westerlies, which is considered as a vital platform to investigate the moisture regime for this region. Since 2011, an observation network of stable isotopes in precipitation was established across the city, and four stations were included in the network. In 2013, six more sampling stations were added, and the enhanced network might provide more meaningful information on spatial incoherence and synoptic process. This study focused on the variations of stable isotopes (δ 18 O and δD) in precipitation and the environmental controls based on the 1432 samples in this enhanced network from April 2011 to October 2014. The results showed that the precipitation isotopes had great spatial diversity, and the neighboring stations may present large difference in δD and δ 18 O. Based on the observation at ten sampling sites, an isoscape in precipitation was calculated, and the method is useful to produce isoscape for small domains. The temperature effect and amount effect was reconsidered based on the dataset. Taking meteorological parameters (temperature, precipitation amount, relative humidity, water vapor pressure and dew point temperature) as variables in a multi-linear regression, the result of coefficients for these meteorological parameters were calculated. Some cases were also involved in this study, and the isotopic characteristics during one event or continuous days were used to understand the environmental controls on precipitation isotopes. Copyright © 2017 Elsevier B.V. All rights reserved.

Species A rotavirus NSP3 acquires its translation inhibitory function prior to stable dimer formation.

Directory of Open Access Journals (Sweden)

Hugo I Contreras-Treviño

Full Text Available Species A rotavirus non-structural protein 3 (NSP3 is a translational regulator that inhibits or, under some conditions, enhances host cell translation. NSP3 binds to the translation initiation factor eIF4G1 and evicts poly-(A binding protein (PABP from eIF4G1, thus inhibiting translation of polyadenylated mRNAs, presumably by disrupting the effect of PABP bound to their 3'-ends. NSP3 has a long coiled-coil region involved in dimerization that includes a chaperone Hsp90-binding domain (HS90BD. We aimed to study the role in NSP3 dimerization of a segment of the coiled-coil region adjoining the HS90BD. We used a vaccinia virus system to express NSP3 with point mutations in conserved amino acids in the coiled-coil region and determined the effects of these mutations on translation by metabolic labeling of proteins as well as on accumulation of stable NSP3 dimers by non-dissociating Western blot, a method that separates stable NSP3 dimers from the monomer/dimerization intermediate forms of the protein. Four of five mutations reduced the total yield of NSP3 and the formation of stable dimers (W170A, K171E, R173E and R187E:K191E, whereas one mutation had the opposite effects (Y192A. Treatment with the proteasome inhibitor MG132 revealed that stable NSP3 dimers and monomers/dimerization intermediates are susceptible to proteasome degradation. Surprisingly, mutants severely impaired in the formation of stable dimers were still able to inhibit host cell translation, suggesting that NSP3 dimerization intermediates are functional. Our results demonstrate that rotavirus NSP3 acquires its function prior to stable dimer formation and remain as a proteasome target throughout dimerization.

Sampling methodology and PCB analysis

International Nuclear Information System (INIS)

Dominelli, N.

1995-01-01

As a class of compounds PCBs are extremely stable and resist chemical and biological decomposition. Diluted solutions exposed to a range of environmental conditions will undergo some preferential degradation and the resulting mixture may differ considerably from the original PCB used as insulating fluid in electrical equipment. The structure of mixtures of PCBs (synthetic compounds prepared by direct chlorination of biphenyl with chlorine gas) is extremely complex and presents a formidable analytical problem, further complicated by the presence of PCBs as contaminants in oils to soils to water. This paper provides some guidance into sampling and analytical procedures; it also points out various potential problems encountered during these processes. The guidelines provided deal with sample collection, storage and handling, sample stability, laboratory analysis (usually gas chromatography), determination of PCB concentration, calculation of total PCB content, and quality assurance. 1 fig

Estimation of food composition of Hodotermes mossambicus (Isoptera: Hodotermitidae) based on observations and stable carbon isotope ratios

CSIR Research Space (South Africa)

Symes, CT

2011-04-01

Full Text Available , observations (93.8%) and stable isotopes (92.6%), no significant differ- ence was recognized (t-test dependent samples, t = 0.84, P = 0.46). Discussion Observations A widely used method of studying feeding habits in termites is by assessing the choice.... Canadian Journal of Zoology, 78, 1?27. LaFage, J.P. and Nutting, W.L. (1978) Food and feeding habits of termites. Nutrient Dynamics of Termites (ed. M.V. Brian), pp. 165?232. Cambridge University Press, Cambridge. McKechnie, A.E. (2004) Stable isotopes...

Photoluminescence studies of ZnO doped with stable and radioactive impurities

CERN Document Server

Cullen, Joseph; Martin O, Henry

In this work the IIb-VI compound semiconductor ZnO is doped, via ion implantation of stable and radioactive isotopes, in order to investigate the chemical nature of exciton re-combinations bound to previously unidentified defects. Photo-luminescence (PL) is discussed and is used extensively as the primary investigative technique. A new defect emission feature, centred around 3.324 eV, is found to be related to Ge impurities occupying substitutional Zn sites in ZnO. This centre is investigated by temperature dependent PL, piezo-spectroscopy and Zeeman spectroscopy. The centre is donor-like in nature. Uniaxial stress measurements indicate that the defect centre has trigonal symmetry and applied magnetic field measurements reveal the neutral charge state of the centre and the donor-like binding mechanism. Subsequent to this, a study is undertaken of the iso-electronic defect Hg in ZnO studying the zero phonon feature at 3.279 eV and its associated phonon replica band. Temperature dependent measurements reveal tw...

Tukey max-stable processes for spatial extremes

KAUST Repository

Xu, Ganggang

2016-09-21

We propose a new type of max-stable process that we call the Tukey max-stable process for spatial extremes. It brings additional flexibility to modeling dependence structures among spatial extremes. The statistical properties of the Tukey max-stable process are demonstrated theoretically and numerically. Simulation studies and an application to Swiss rainfall data indicate the effectiveness of the proposed process. © 2016 Elsevier B.V.

Activated carbon derived from waste coffee grounds for stable methane storage

International Nuclear Information System (INIS)

Kemp, K Christian; Baek, Seung Bin; Lee, Wang-Geun; Kim, Kwang S; Meyyappan, M

2015-01-01

An activated carbon material derived from waste coffee grounds is shown to be an effective and stable medium for methane storage. The sample activated at 900 °C displays a surface area of 1040.3 m"2 g"−"1 and a micropore volume of 0.574 cm"3 g"−"1 and exhibits a stable CH_4 adsorption capacity of ∼4.2 mmol g"−"1 at 3.0 MPa and a temperature range of 298 ± 10 K. The same material exhibits an impressive hydrogen storage capacity of 1.75 wt% as well at 77 K and 100 kPa. Here, we also propose a mechanism for the formation of activated carbon from spent coffee grounds. At low temperatures, the material has two distinct types with low and high surface areas; however, activation at elevated temperatures drives off the low surface area carbon, leaving behind the porous high surface area activated carbon. (paper)

Development of shelf-stable meat sausages using gamma irradiation

International Nuclear Information System (INIS)

Seri Chempaka Mohd Yusof; Muhammad Lebai Juri; Mariani Deraman

2006-01-01

Irradiation techniques have been applied in development of ready to eat or shelf stable sausages. These sausages can be eaten directly without the need for prior heating or cooking procedure and displayed in the room temperature on the shelves of the retailers without frozen facilities. This study was designed to investigate the acceptability and microbial status of packed ready to eat sausages that had been sterilized using gamma irradiation at MINTec-Sinagama. Packed pre-cooked sausage samples (sealed in plastic-polyethylene individually) were irradiated with different doses of 2.5 kGy, 3.5 kGy and 5.5 kGy. Acceptability of the sausages was determined through sensory evaluation by 30 members of untrained panelists comprising of staffs of MINT. A 5 points hedonic rating scale was used. The attributes evaluated were rancidity, texture, chewiness, juiciness, aroma, colour, shape and overall acceptance. Samples irradiated with doses 3.5 kGy were the most acceptable followed by samples irradiated with doses 2.5 kGy and 5.5 kGy respectively. Irradiation with doses up to 2.5 kGy will virtually eliminate disease-causing microorganisms and pathogens. The total microbial count, detection of Salmonella, Escherichia coli, Staphylococcus aureus and fungi in these samples were determined and discussed. (Author)

Mechanistic Insights on Human Phosphoglucomutase Revealed by Transition Path Sampling and Molecular Dynamics Calculations.

Science.gov (United States)

Brás, Natércia F; Fernandes, Pedro A; Ramos, Maria J; Schwartz, Steven D

2018-02-06

Human α-phosphoglucomutase 1 (α-PGM) catalyzes the isomerization of glucose-1-phosphate into glucose-6-phosphate (G6P) through two sequential phosphoryl transfer steps with a glucose-1,6-bisphosphate (G16P) intermediate. Given that the release of G6P in the gluconeogenesis raises the glucose output levels, α-PGM represents a tempting pharmacological target for type 2 diabetes. Here, we provide the first theoretical study of the catalytic mechanism of human α-PGM. We performed transition-path sampling simulations to unveil the atomic details of the two catalytic chemical steps, which could be key for developing transition state (TS) analogue molecules with inhibitory properties. Our calculations revealed that both steps proceed through a concerted S N 2-like mechanism, with a loose metaphosphate-like TS. Even though experimental data suggests that the two steps are identical, we observed noticeable differences: 1) the transition state ensemble has a well-defined TS region and a late TS for the second step, and 2) larger coordinated protein motions are required to reach the TS of the second step. We have identified key residues (Arg23, Ser117, His118, Lys389), and the Mg 2+ ion that contribute in different ways to the reaction coordinate. Accelerated molecular dynamics simulations suggest that the G16P intermediate may reorient without leaving the enzymatic binding pocket, through significant conformational rearrangements of the G16P and of specific loop regions of the human α-PGM. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stable configurations of graphene on silicon

Energy Technology Data Exchange (ETDEWEB)

Javvaji, Brahmanandam; Shenoy, Bhamy Maithry [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India); Mahapatra, D. Roy, E-mail: droymahapatra@aero.iisc.ernet.in [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India); Ravikumar, Abhilash [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025 (India); Hegde, G.M. [Center for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012 (India); Rizwan, M.R. [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025 (India)

2017-08-31

Highlights: • Simulations of epitaxial growth process for silicon–graphene system is performed. • Identified the most favourable orientation of graphene sheet on silicon substrate. • Atomic local strain due to the silicon–carbon bond formation is analyzed. - Abstract: Integration of graphene on silicon-based nanostructures is crucial in advancing graphene based nanoelectronic device technologies. The present paper provides a new insight on the combined effect of graphene structure and silicon (001) substrate on their two-dimensional anisotropic interface. Molecular dynamics simulations involving the sub-nanoscale interface reveal a most favourable set of temperature independent orientations of the monolayer graphene sheet with an angle of ∽15° between its armchair direction and [010] axis of the silicon substrate. While computing the favorable stable orientations, both the translation and the rotational vibrations of graphene are included. The possible interactions between the graphene atoms and the silicon atoms are identified from their coordination. Graphene sheet shows maximum bonding density with bond length 0.195 nm and minimum bond energy when interfaced with silicon substrate at 15° orientation. Local deformation analysis reveals probability distribution with maximum strain levels of 0.134, 0.047 and 0.029 for 900 K, 300 K and 100 K, respectively in silicon surface for 15° oriented graphene whereas the maximum probable strain in graphene is about 0.041 irrespective of temperature. Silicon–silicon dimer formation is changed due to silicon–carbon bonding. These results may help further in band structure engineering of silicon–graphene lattice.

Stable isotope characterization of pan-derived and directly sampled atmospheric water vapour

International Nuclear Information System (INIS)

Maric, R.; St. Amour, N.A.; Gibson, J.J.; Edwards, T.W.D.

2002-01-01

Isotopic characterization of atmospheric water vapour, δ A , and its temporal variability are important prerequisites for quantifying water balance of surface reservoirs and partitioning of evaporation and transpiration fluxes using isotope techniques. Here we present results from a detailed comparison of several methods for determining δ A in field situations, (i) by back-calculation from isotopic and micrometeorological monitoring of a steady-state terminal reservoir (standard Class-A evaporation pan) using boundary-layer mass transfer models [1], (ii) through direct (cryogenic) sampling of ambient atmospheric moisture, and (iii) using the precipitation-equilibrium approximation (i.e., δ A =δ P - ε*)

Chance and stability stable distributions and their applications

CERN Document Server

Uchaikin, Vladimir V

1999-01-01

An introduction to the theory of stable distributions and their applications. It contains a modern outlook on the mathematical aspects of the theory. The authors explain numerous peculiarities of stable distributions and describe the principle concept of probability theory and function analysis. A significant part of the book is devoted to applications of stable distributions. Another notable feature is the material on the interconnection of stable laws with fractals, chaos and anomalous transport processes.

Non-destructive evaluation of scientific and biological samples by scattering of 145 keV gamma rays

International Nuclear Information System (INIS)

Singh, M.P.; Sharma, Amandeep; Singh, Bhajan; Sandhu, B.S.

2010-01-01

The objective of present experiment is to assign effective atomic number (Z eff ) to samples of scientific interest (oxides of lanthanoids, also called rare earths, and alloys of lead and tin of known composition) and to measure stable iodine content of tissue (biological sample). An HPGe semiconductor detector, placed at 70 o to the incident beam, detects gamma photons scattered from the sample under investigation. The experiment is performed on various elements with atomic number satisfying, 6 ≤Z ≤ 82, for 145 keV incident photons. The intensity ratio of Rayleigh to Compton scattered peaks, corrected for photo-peak efficiency of gamma detector and absorption of photons in the sample and air, is plotted as a function of atomic number and constituted a fit curve. From this fit curve, the respective effective atomic numbers of the scientific samples are determined. The agreement of measured values of Z eff with theoretical calculations is found to be quite satisfactory. The measured intensity ratio from phantom (KI solutions, simulating thyroid content of stable iodine) varies linearly with KI concentration and provides stable iodine content of tissue.

Effects of Water Vapor on the Data Quality of the Stable Oxygen Isotopic Ratio of Atmospheric Carbon Dioxide

Science.gov (United States)

Evans, C. U.; White, J. W.; Vaughn, B.; Tans, P. P.; Pardo, L.

2007-12-01

The stable oxygen isotopic ratio of carbon dioxide can potentially track fundamental indicators of environmental change such as the balance between photosynthesis and respiration on regional to global scales. The Stable Isotope Laboratory (SIL) at the Institute of Arctic and Alpine Research (INSTAAR), University of Colorado at Boulder, has measured the stable isotopes of atmospheric carbon dioxide from more than 60 NOAA/Earth System Research Laboratory (ESRL) air flask-sampling sites since the early 1990s. If air is sampled without drying, oxygen can exchange between carbon dioxide and water in the flasks, entirely masking the desired signal. An attempt to investigate how water vapor is affecting the δ18O signal is accomplished by comparing the SIL measurements with specific humidity, calculated from the National Climatic Data Center (NCDC) global integrated surface hourly temperature and dew point database, at the time of sampling. Analysis of sites where samples have been collected initially without drying, and subsequently with a drying kit, in conjunction with the humidity data, has led to several conclusions. Samples that initially appear isotopically unaltered, in that their δ18O values are within the expected range, are being subtly influenced by the water vapor in the air. At Bermuda and other tropical to semi-tropical sites, the 'wet' sampling values have a seasonal cycle that is strongly anti-correlated to the specific humidity, while the 'dry' values have a seasonal cycle that is shifted earlier than the specific humidity cycle by 1-2 months. The latter phasing is expected given the seasonal phasing between climate over the ocean and land, while the former is consistent with a small, but measurable isotope exchange in the flasks. In addition, we note that there is a strong (r > 0.96) correlation between the average specific humidity and the percent of rejected samples for 'wet' sampling. This presents an opportunity for determining a threshold of

Magnetic force microscopy reveals meta-stable magnetic domain states that prevent reliable absolute palaeointensity experiments

NARCIS (Netherlands)

de Groot, Lennart; Fabian, Karl; Bakelaar, Iman A.; Dekkers, Mark J.

2014-01-01

Obtaining reliable estimates of the absolute palaeointensity of the Earth's magnetic field is notoriously difficult. The heating of samples in most methods induces magnetic alteration-a process that is still poorly understood, but prevents obtaining correct field values. Here we show induced changes

French days on stable isotopes

International Nuclear Information System (INIS)

2000-01-01

These first French days on stable isotopes took place in parallel with the 1. French days of environmental chemistry. Both conferences had common plenary sessions. The conference covers all aspects of the use of stable isotopes in the following domains: medicine, biology, environment, tracer techniques, agronomy, food industry, geology, petroleum geochemistry, cosmo-geochemistry, archaeology, bio-geochemistry, hydrology, climatology, nuclear and particle physics, astrophysics, isotope separations etc.. Abstracts available on CD-Rom only. (J.S.)

Pharmaceuticals labelled with stable isotopes

International Nuclear Information System (INIS)

Krumbiegel, P.

1986-11-01

The relatively new field of pharmaceuticals labelled with stable isotopes is reviewed. Scientific, juridical, and ethical questions are discussed concerning the application of these pharmaceuticals in human medicine. 13 C, 15 N, and 2 H are the stable isotopes mainly utilized in metabolic function tests. Methodical contributions are given to the application of 2 H, 13 C, and 15 N pharmaceuticals showing new aspects and different states of development in the field under discussion. (author)

Development of a Safety Management Web Tool for Horse Stables.

Science.gov (United States)

Leppälä, Jarkko; Kolstrup, Christina Lunner; Pinzke, Stefan; Rautiainen, Risto; Saastamoinen, Markku; Särkijärvi, Susanna

2015-11-12

Managing a horse stable involves risks, which can have serious consequences for the stable, employees, clients, visitors and horses. Existing industrial or farm production risk management tools are not directly applicable to horse stables and they need to be adapted for use by managers of different types of stables. As a part of the InnoEquine project, an innovative web tool, InnoHorse, was developed to support horse stable managers in business, safety, pasture and manure management. A literature review, empirical horse stable case studies, expert panel workshops and stakeholder interviews were carried out to support the design. The InnoHorse web tool includes a safety section containing a horse stable safety map, stable safety checklists, and examples of good practices in stable safety, horse handling and rescue planning. This new horse stable safety management tool can also help in organizing work processes in horse stables in general.

Modern rather than Mesoarchaean oxidative weathering responsible for the heavy stable Cr isotopic signatures of the 2.95 Ga old Ijzermijn iron formation (South Africa)

Science.gov (United States)

Albut, Gülüm; Babechuk, Michael G.; Kleinhanns, Ilka C.; Benger, Manuela; Beukes, Nicolas J.; Steinhilber, Bernd; Smith, Albertus J. B.; Kruger, Stephanus J.; Schoenberg, Ronny

2018-05-01

Previously reported stable Cr isotopic fractionation in Archaean paleosols and iron formations (IFs) have been interpreted as a signature of oxidative weathering of Cr(III) to Cr(VI) in soils, and delivery of isotopically heavy Cr(VI) into the oceans. One of the oldest reported fingerprints of this process is isotopically heavy Cr preserved in the 2.95 Ga old Ijzermijn IF, Sinqeni Formation of the Mozaan Group (Pongola Supergroup), South Africa and could suggest that atmospheric free oxygen was present ca. 600 million years earlier than the Great Oxidation Event (GOE). However, fractionated stable Cr isotopic signatures have only been found to date in surface outcrop samples of the White Mfolozi Inlier exposed along the White Mfolozi River Gorge. In this study, the latter outcrop was resampled along with two drill cores of the Ijzermijn IF and a drill core of the Scotts Hill IF to represent multiple exposures of Mozaan Group IFs with different states of preservation. A detailed geochemical comparison on bulk samples of different units was undertaken using stable Cr isotopes coupled with trace and major elements. Outcrop iron-rich mudstones (Fe - lutites) show very low LOI [wt] %, and very low Fe(II)/Fetot ratios, and lower Ca and Mg relative to equivalent facies in drill cores, indicating the effects that oxidative recent surface weathering had on Fe/Mn-rich carbonate minerals of the IF. Overall rare earth element and yttrium (REE + Y) mixing models agree well with previous studies, confirming that they were minimally disturbed by weathering and are consistent with a high magnitude of continental solutes delivered in a near-shore depositional environment, with a minor contribution of hydrothermally derived fluids that upwelled into shallower depositional setting. Importantly, all drill core samples of this study revealed δ53/52Cr values within the igneous inventory, despite variable amounts of detrital Cr input that includes nearly detritus-free, chert

Stable Isotope Systematics of Coalbed Gas during Desorption and Production

Directory of Open Access Journals (Sweden)

Martin Niemann

2017-06-01

Full Text Available The stable carbon isotope ratios of coalbed methane (CBM demonstrate diagnostic changes that systematically vary with production and desorption times. These shifts can provide decisive, predictive information on the behaviour and potential performance of CBM operations. Samples from producing CBM wells show a general depletion in 13C-methane with increasing production times and corresponding shifts in δ13C-CH4 up to 35.8‰. Samples from canister desorption experiments show mostly enrichment in 13C for methane with increasing desorption time and isotope shifts of up to 43.4‰. Also, 13C-depletion was observed in some samples with isotope shifts of up to 32.1‰. Overall, the magnitudes of the observed isotope shifts vary considerably between different sample sets, but also within samples from the same source. The δ13C-CH4 values do not have the anticipated signature of methane generated from coal. This indicates that secondary processes, including desorption and diffusion, can influence the values. It is also challenging to deconvolute these various secondary processes because their molecular and isotope effects can have similar directions and/or magnitudes. In some instances, significant alteration of CBM gases has to be considered as a combination of secondary alteration effects.

Improved Sensitivity of Spectroscopic Quantification of Stable Isotope Content Using Capillary Absorption Spectroscopy

Science.gov (United States)

Moran, J.; Wilcox Freeburg, E.; Kriesel, J.; Linley, T. J.; Kelly, J.; Coleman, M. L.; Christensen, L. E.; Vance, S.

2016-12-01

Spectroscopy-based platforms have recently risen to the forefront for making stable isotope measurements of methane, carbon dioxide, water, or other analytes. These spectroscopy systems can be relatively straightforward to operate (versus a mass spectrometry platform), largely relieve the analyst of mass interference artifacts, and many can be used in the field. Despite these significant advantages, however, existing spectroscopy techniques suffer from a lack of measurement sensitivity that can ultimately limit select applications including spatially resolved and compound-specific measurements. Here we present a capillary absorption spectroscopy (CAS) system that is designed to mitigate sensitivity issues in spectroscopy-based stable isotope evaluation. The system uses mid-wave infrared excitation generated from a continuous wave quantum cascade laser. Importantly, the sample `chamber' is a flexible capillary with a total volume of less than one cc. Proprietary coatings on the internal surface of the fiber improve optical performance, guiding the light to a detector and facilitating high levels of interaction between the laser beam and gaseous analytes. We present data demonstrating that a tapered hollow fiber cell, with an internal diameter that broadens toward the detector, reduces optical feedback to further improve measurement sensitivity. Sensitivity of current hollow fiber / CAS systems enable measurements of only 10's of picomoles CO2 while theoretical improvements should enable measurements of as little as 10's of femtomoles. Continued optimization of sample introduction and improvements to optical feedback are being explored. Software is being designed to provide rapid integration of data and generation of processed isotope measurements using a graphical user interface. Taken together, the sensitivity improvements of the CAS system under development could, when coupled to a laser ablation sampling device, enable up to 2 µm spatial resolution (roughly the

[Research progress on food sources and food web structure of wetlands based on stable isotopes].

Science.gov (United States)

Chen, Zhan Yan; Wu, Hai Tao; Wang, Yun Biao; Lyu, Xian Guo

2017-07-18

The trophic dynamics of wetland organisms is the basis of assessing wetland structure and function. Stable isotopes of carbon and nitrogen have been widely applied to identify trophic relationships in food source, food composition and food web transport in wetland ecosystem studies. This paper provided an overall review about the current methodology of isotope mixing model and trophic level in wetland ecosystems, and discussed the standards of trophic fractionation and baseline. Moreover, we characterized the typical food sources and isotopic compositions of wetland ecosystems, summarized the food sources in different trophic levels of herbivores, omnivores and carnivores based on stable isotopic analyses. We also discussed the limitations of stable isotopes in tra-cing food sources and in constructing food webs. Based on the current results, development trends and upcoming requirements, future studies should focus on sample treatment, conservation and trophic enrichment measurement in the wetland food web, as well as on combing a variety of methodologies including traditional stomach stuffing, molecular markers, and multiple isotopes.

Tempered stable distributions stochastic models for multiscale processes

CERN Document Server

Grabchak, Michael

2015-01-01

This brief is concerned with tempered stable distributions and their associated Levy processes. It is a good text for researchers interested in learning about tempered stable distributions.  A tempered stable distribution is one which takes a stable distribution and modifies its tails to make them lighter. The motivation for this class comes from the fact that infinite variance stable distributions appear to provide a good fit to data in a variety of situations, but the extremely heavy tails of these models are not realistic for most real world applications. The idea of using distributions that modify the tails of stable models to make them lighter seems to have originated in the influential paper of Mantegna and Stanley (1994). Since then, these distributions have been extended and generalized in a variety of ways. They have been applied to a wide variety of areas including mathematical finance, biostatistics,computer science, and physics.

Rare stable isotopes in meteorites

International Nuclear Information System (INIS)

Wilson, G.C.

1981-01-01

Secondary Ion Mass Spectrometry (SIMS) using accelerators has been applied with success to cosmic ray exposure ages and terrestrial residence times of meteorites by measuring cosmogenic nuclides of Be, Cl, and I. It is proposed to complement this work with experiments on rare stable isotopes, in the hope of setting constraints on the processes of solar nebula/meteoritic formation. The relevant species can be classified as: a) daughter products of extinct nuclides (halflife less than or equal to 2 x 10 8 y) -chronology of the early solar system; b) products of high temperature astrophysical processes - different components incorporated into the solar nebula; and c) products of relatively low temperature processes, stellar winds and cosmic ray reactions - early solar system radiation history. The use of micron-scale primary ion beams will allow detailed sampling of phases within meteorites. Strategies of charge-state selection, molecular disintegration and detection should bring a new set of targets within analytical range. The developing accelerator field is compared to existing (keV energy) ion microprobes

Combining metagenomics with metaproteomics and stable isotope probing reveals metabolic pathways used by a naturally occurring marine methylotroph

DEFF Research Database (Denmark)

Grob, Carolina; Taubert, Martin; Howat, Alexandra M.

2015-01-01

A variety of culture-independent techniques have been developed that can be used in conjunction with culture-dependent physiological and metabolic studies of key microbial organisms in order to better understand how the activity of natural populations influences and regulates all major......, we retrieved virtually the whole genome of this bacterium and determined its metabolic potential. Through protein-stable isotope probing, the RuMP cycle was established as the main carbon assimilation pathway, and the classical methanol dehydrogenase-encoding gene mxaF, as well as three out of four...... identified xoxF homologues were found to be expressed. This proof-of-concept study is the first in which the culture-independent techniques of DNA-SIP and protein-SIP have been used to characterize the metabolism of a naturally occurring Methylophaga-like bacterium in the marine environment (i...

ISOTOPE-DILUTION AMMONIA CHEMICAL-IONIZATION MASS FRAGMENTOGRAPHIC ANALYSIS OF URINARY 3-O-METHYLATED CATECHOLAMINE METABOLITES - RAPID SAMPLE CLEANUP BY DERIVATIZATION AND EXTRACTION OF LYOPHILIZED SAMPLES

NARCIS (Netherlands)

KEMA, IP; MEIBORG, G; NAGEL, GT; STOB, GJ; MUSKIET, FAJ

1993-01-01

We developed a method for simultaneous quantification of the urinary 3-O-methylated catecholamine metabolites 3-methoxytyramine, normetanephrine and metanephrine by stable isotope-dilution ammonia chemical ionization mass fragmentography. Prepurification of lyophilized samples was done by

Extensive monitoring through multiple blood samples in professional soccer players.

Science.gov (United States)

Heisterberg, Mette F; Fahrenkrug, Jan; Krustrup, Peter; Storskov, Anders; Kjær, Michael; Andersen, Jesper L

2013-05-01

The aim of this study was to make a comprehensive gathering of consecutive detailed blood samples from professional soccer players and to analyze different blood parameters in relation to seasonal changes in training and match exposure. Blood samples were collected 5 times during a 6-month period and analyzed for 37 variables in 27 professional soccer players from the best Danish league. Additionally, the players were tested for body composition, V[Combining Dot Above]O2max and physical performance by the Yo-Yo intermittent endurance submax test (IE2). Multiple variations in blood parameters occurred during the observation period, including a decrease in hemoglobin and an increase in hematocrit as the competitive season progressed. Iron and transferrin were stable, whereas ferritin showed a decrease at the end of the season. The immunoglobulin A (IgA) and IgM increased in the period with basal physical training and at the end of the season. Leucocytes decreased with increased physical training. Lymphocytes decreased at the end of the season. The V[Combining Dot Above]O2max decreased toward the end of the season, whereas no significant changes were observed in the IE2 test. The regular blood samples from elite soccer players reveal significant changes that may be related to changes in training pattern, match exposure, or length of the match season. Especially the end of the preparation season and at the end of the competitive season seem to be time points were the blood-derived values indicate that the players are under excessive physical strain and might be more subjected to a possible overreaching-overtraining conditions. We suggest that regular analyses of blood samples could be an important initiative to optimize training adaptation, training load, and game participation, but sampling has to be regular, and a database has to be built for each individual player.

Pallid bands in feathers and associated stable isotope signatures reveal effects of severe weather stressors on fledgling sparrows.

Science.gov (United States)

Ross, Jeremy D; Kelly, Jeffrey F; Bridge, Eli S; Engel, Michael H; Reinking, Dan L; Boyle, W Alice

2015-01-01

In August 2013, we observed a high incidence (44%) of synchronous bands of reduced melanin (a type of fault bar we have termed "pallid bands") across the rectrices of juvenile Grasshopper Sparrows (Ammodrammus savannarum) captured near El Reno, Oklahoma. Earlier that year, on May 31, the site was struck by a severe storm which rained hailstones exceeding 5.5 cm diameter and spawned an historic 4.2 km-wide tornado stressor had induced the pallid bands. An assessment of Grasshopper Sparrow nesting phenology indicated that a large number of nestlings were likely growing tail feathers when the storm hit. The pallid bands were restricted to the distal half of feathers and their widths significantly increased as a function of distance from the tip (i.e., age at formation). We predicted that if stress had caused these pallid bands, then a spike in circulating δ (15)N originating from tissue catabolism during the stress response would have been incorporated into the developing feather. From 18 juveniles captured at the site in August we measured δ (15)N and δ (13)C stable isotope ratios within four to five 0.25-0.40 mg feather sections taken from the distal end of a tail feather; the pallid band, if present, was contained within only one section. After accounting for individual and across-section variation, we found support for our prediction that feather sections containing or located immediately proximal to pallid bands (i.e., the pallid band region) would show significantly higher δ (15)N than sections outside this region. In contrast, the feathers of juveniles with pallid bands compared to normal appearing juveniles showed significantly lower δ (15)N. A likely explanation is that the latter individuals hatched after the May 31 storm and had consumed a trophically-shifted diet relative to juveniles with pallid bands. Considering this, the juveniles of normal appearance were significantly less abundant within our sample relative to expectations from past cohorts (z

Pallid bands in feathers and associated stable isotope signatures reveal effects of severe weather stressors on fledgling sparrows

Directory of Open Access Journals (Sweden)

Jeremy D. Ross

2015-03-01

Full Text Available In August 2013, we observed a high incidence (44% of synchronous bands of reduced melanin (a type of fault bar we have termed “pallid bands” across the rectrices of juvenile Grasshopper Sparrows (Ammodrammus savannarum captured near El Reno, Oklahoma. Earlier that year, on May 31, the site was struck by a severe storm which rained hailstones exceeding 5.5 cm diameter and spawned an historic 4.2 km-wide tornado <8 km to the south of the site. We hypothesized that this stressor had induced the pallid bands. An assessment of Grasshopper Sparrow nesting phenology indicated that a large number of nestlings were likely growing tail feathers when the storm hit. The pallid bands were restricted to the distal half of feathers and their widths significantly increased as a function of distance from the tip (i.e., age at formation. We predicted that if stress had caused these pallid bands, then a spike in circulating δ15N originating from tissue catabolism during the stress response would have been incorporated into the developing feather. From 18 juveniles captured at the site in August we measured δ15N and δ13C stable isotope ratios within four to five 0.25–0.40 mg feather sections taken from the distal end of a tail feather; the pallid band, if present, was contained within only one section. After accounting for individual and across-section variation, we found support for our prediction that feather sections containing or located immediately proximal to pallid bands (i.e., the pallid band region would show significantly higher δ15N than sections outside this region. In contrast, the feathers of juveniles with pallid bands compared to normal appearing juveniles showed significantly lower δ15N. A likely explanation is that the latter individuals hatched after the May 31 storm and had consumed a trophically-shifted diet relative to juveniles with pallid bands. Considering this, the juveniles of normal appearance were significantly less abundant

Stable Chimeras and Independently Synchronizable Clusters

Science.gov (United States)

Cho, Young Sul; Nishikawa, Takashi; Motter, Adilson E.

2017-08-01

Cluster synchronization is a phenomenon in which a network self-organizes into a pattern of synchronized sets. It has been shown that diverse patterns of stable cluster synchronization can be captured by symmetries of the network. Here, we establish a theoretical basis to divide an arbitrary pattern of symmetry clusters into independently synchronizable cluster sets, in which the synchronization stability of the individual clusters in each set is decoupled from that in all the other sets. Using this framework, we suggest a new approach to find permanently stable chimera states by capturing two or more symmetry clusters—at least one stable and one unstable—that compose the entire fully symmetric network.

Stable Breathing in Patients With Obstructive Sleep Apnea Is Associated With Increased Effort but Not Lowered Metabolic Rate.

Science.gov (United States)

de Melo, Camila M; Taranto-Montemurro, Luigi; Butler, James P; White, David P; Loring, Stephen H; Azarbarzin, Ali; Marques, Melania; Berger, Philip J; Wellman, Andrew; Sands, Scott A

2017-10-01

In principle, if metabolic rate were to fall during sleep in a patient with obstructive sleep apnea (OSA), ventilatory requirements could be met without increased respiratory effort thereby favoring stable breathing. Indeed, most patients achieve periods of stable flow-limited breathing without respiratory events for periods during the night for reasons that are unclear. Thus, we tested the hypothesis that in patients with OSA, periods of stable breathing occur when metabolic rate (VO2) declines. Twelve OSA patients (apnea-hypopnea index >15 events/h) completed overnight polysomnography including measurements of VO2 (using ventilation and intranasal PO2) and respiratory effort (esophageal pressure). Contrary to our hypothesis, VO2 did not differ between stable and unstable breathing periods in non-REM stage 2 (208 ± 20 vs. 213 ± 18 mL/min), despite elevated respiratory effort during stable breathing (26 ± 2 versus 23 ± 2 cmH2O, p = .03). However, VO2 was lowered during deeper sleep (244 to 179 mL/min from non-REM stages 1 to 3, p = .04) in conjunction with more stable breathing. Further analysis revealed that airflow obstruction curtailed metabolism in both stable and unstable periods, since CPAP increased VO2 by 14% in both cases (p = .02, .03, respectively). Patients whose VO2 fell most during sleep avoided an increase in PCO2 and respiratory effort. OSA patients typically convert from unstable to stable breathing without lowering metabolic rate. During sleep, OSA patients labor with increased respiratory effort but fail to satisfy metabolic demand even in the absence of overt respiratory events. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Population Screening Using Sewage Reveals Pan-Resistant Bacteria in Hospital and Community Samples.

Science.gov (United States)

Meir-Gruber, Lital; Manor, Yossi; Gefen-Halevi, Shiraz; Hindiyeh, Musa Y; Mileguir, Fernando; Azar, Roberto; Smollan, Gill; Belausov, Natasha; Rahav, Galia; Shamiss, Ari; Mendelson, Ella; Keller, Nathan

2016-01-01

The presence of pan-resistant bacteria worldwide possesses a threat to global health. It is difficult to evaluate the extent of carriage of resistant bacteria in the population. Sewage sampling is a possible way to monitor populations. We evaluated the presence of pan-resistant bacteria in Israeli sewage collected from all over Israel, by modifying the pour plate method for heterotrophic plate count technique using commercial selective agar plates. This method enables convenient and fast sewage sampling and detection. We found that sewage in Israel contains multiple pan-resistant bacteria including carbapenemase resistant Enterobacteriacae carrying blaKPC and blaNDM-1, MRSA and VRE. blaKPC carrying Klebsiella pneumonia and Enterobacter cloacae were the most common Enterobacteriacae drug resistant bacteria found in the sewage locations we sampled. Klebsiella pneumonia, Enterobacter spp., Escherichia coli and Citrobacter spp. were the 4 main CRE isolated from Israeli sewage and also from clinical samples in our clinical microbiology laboratory. Hospitals and Community sewage had similar percentage of positive samplings for blaKPC and blaNDM-1. VRE was found to be more abundant in sewage in Israel than MRSA but there were more locations positive for MRSA and VRE bacteria in Hospital sewage than in the Community. Therefore, our upgrade of the pour plate method for heterotrophic plate count technique using commercial selective agar plates can be a useful tool for routine screening and monitoring of the population for pan-resistant bacteria using sewage.

Shelf stable intermediate moisture fruit cubes using radiation technology

International Nuclear Information System (INIS)

Mishra, Bibhuti B.; Saxena, Sudhanshu; Gautam, Satyendra; Chander, Ramesh; Sharma, Arun

2009-01-01

A process has been developed to prepare shelf stable ready-to-eat (RTE) intermediate moisture pineapple slices and papaya cubes using radiation technology. The combination of hurdles including osmotic dehydration, blanching, infrared drying, and gamma radiation dose of 1 kGy successfully reduced the microbial load to below detectable limit. The shelf life of the intermediate moisture pineapple slices and papaya cubes was found to be 40 days at ambient temperature (28 ± 2 deg C). The control samples spoiled within 6 days. The RTE intermediate moisture fruit products were found to have good texture, colour and sensory acceptability during this 40 days storage. (author)

Stable Nd isotope variations in the inner Solar System: The effect of sulfide during differentiation?

Science.gov (United States)

McCoy-West, A.

2017-12-01

Radiogenic neodymium isotopes have been widely used in studies of planetary accretion to constrain the timescales of early planetary differention [1]. Whereas stable isotope varitaions potentially provide information on the the processes that occur during planet formation. Experimental work suggests that the Earth's core contains a significant proportion of sulfide [2], and recent experimental work shows that under reducing conditions sulfide can incorporate substantial quantities of refractory lithophile elements [including Nd; 3]. If planetary embroyos also contain sulfide-rich cores, Nd stable isotopes have the potential to trace this sulfide segregation event in highly reduced environments, because there is a significant contrast in bonding environment between sulfide and silicate, where heavy isotopes should be preferentially incorporated into high force-constant bonds involving REE3+ (i.e. the silicate mantle). Here we present 146Nd/144Nd data, obtained using a double spike TIMS technique, for a range of planetary bodies formed at variable oxidation states including samples from the Moon, Mars, the asteriod 4Vesta and the Angrite and Aubrite parent bodies. Analyses of chondritic meteorites and terrestrial igneous rocks indicate that the Earth has a Nd stable isotope composition that is indistinguishable from that of chondrites [4]. Eucrites and martian meteorites also have compositons within error of the chondritic average. Significantly more variabilty is observed in the low concentration lunar samples and diogienite meteorites with Δ146Nd = 0.16‰. Preliminary results suggest that the Nd stable isotope composition of oxidised planetary bodies are homogeneous and modifications are the result of subordinate magmatic processes. [1] Boyet & Carlson, Science 309, 576 (2005) [2] Labidi et al. Nature 501, 208 (2013); [3] Wohlers &Wood, Nature 520, 337 (2015); [4] McCoy-West et al. Goldschmidt Ab. 429 (2017).

Determination of iodine in biological samples by neutron activation analysis (NAA)

International Nuclear Information System (INIS)

Geetha, P.V.; Karunakara, N.; Prabhu, Ujwal; Yashodhara, I.; Ravi, P.M.; Sudhakar, J.; Ajith, Nicy; Swain, K.K.; Verma, R.; Reddy, A.V.R.; Acharya, R.

2010-01-01

During normal operating conditions of a nuclear reactor, the release of radionuclides to the environment will be extremely low and well within the limits. Radioiodine ( 131 I) is one of the radionuclides likely to get released into the atmosphere in case of a reactor accident. During the short initial phase of release of radioactivity, 131 I is rapidly transferred to milk, leading to significant thyroid dose to those consuming milk, especially infant and children. Hence, studies on Iodine transfer through grass-cow-milk is very important. Extensive studies on transfer for 131 I through grass-cow-milk pathway after Chernobyl accident has been reported. But, under normal operational conditions of the power reactor, 131 I is not present in measurable concentration in environmental matrices of a nuclear power generating station. Stable iodine is present in all environmental samples and from the concentration of stable iodine in grass and milk, one can estimate the transfer factor. The measurement of stable iodine in environmental sample is very challenging because of its extremely low concentration. Neutron activation analysis can be used for estimation of stable iodine in the environment after suitably optimizing the condition to minimize interferences. A method has been developed based on thermal neutron activation analysis (NAA) to estimate the iodine concentration present in grass and cow milk

Abraham Reef Stable Isotope Data (delta 13C, delta 18O, delta 14C) for 1635-1957

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Site: Abraham Reef, 22ó 06'S, 153ó 00'E, Porites australiensus, Radiocarbon (delta 14C) and Stable Isotope (del 18O and del 13C) results from bi-annual samples from...

Large Sample Neutron Activation Analysis of Heterogeneous Samples

International Nuclear Information System (INIS)

Stamatelatos, I.E.; Vasilopoulou, T.; Tzika, F.

2018-01-01

A Large Sample Neutron Activation Analysis (LSNAA) technique was developed for non-destructive analysis of heterogeneous bulk samples. The technique incorporated collimated scanning and combining experimental measurements and Monte Carlo simulations for the identification of inhomogeneities in large volume samples and the correction of their effect on the interpretation of gamma-spectrometry data. Corrections were applied for the effect of neutron self-shielding, gamma-ray attenuation, geometrical factor and heterogeneous activity distribution within the sample. A benchmark experiment was performed to investigate the effect of heterogeneity on the accuracy of LSNAA. Moreover, a ceramic vase was analyzed as a whole demonstrating the feasibility of the technique. The LSNAA results were compared against results obtained by INAA and a satisfactory agreement between the two methods was observed. This study showed that LSNAA is a technique capable to perform accurate non-destructive, multi-elemental compositional analysis of heterogeneous objects. It also revealed the great potential of the technique for the analysis of precious objects and artefacts that need to be preserved intact and cannot be damaged for sampling purposes. (author)

Synthesis and photophysical characterizations of thermal-stable naphthalene benzimidazoles.

Science.gov (United States)

Erten-Ela, Sule; Ozcelik, Serdar; Eren, Esin

2011-07-01

Microwave-assisted synthesis, photophysical and electrochemical properties of thermal-stable naphthalene benzimidazoles and naphthalimides are studied in this paper. Microwave-assisted synthesis of naphthalene benzimidazoles provide higher yields than the conventional thermal synthesis. Comparative photophysical properties of naphthalene benzimidazoles and naphthalimides are revealed that conjugation of electron-donating group onto naphthalimide moiety increases fluorescence quantum yields. Fluorophore-solvent interactions are also investigated using Lippert-Mataga equation for naphthalimides and naphthalene benzimidazoles. Thermal stabilities of naphthalene benzimidazoles are better than naphthalimides due to increased aromaticity. The experimental E(LUMO) levels of naphthalene benzimidazoles are found to be between 3.15 and 3.28 eV. Therefore, naphthalene benzimidazole derivatives consisting of anchoring groups are promising materials in organic dye sensitized solar cells. © Springer Science+Business Media, LLC 2011

Stable isotope ratio mass spectrometry in forensic science and food adulteration research

International Nuclear Information System (INIS)

Kumar, B.

2009-01-01

Stable Isotope Ratio Mass Spectrometry (SIRMS) is an established technique for the determination of origin of geological, biological, chemical and physio-chemical samples/materials. With the development of highly precise mass spectrometers, the stable isotope ratio determination of hydrogen, carbon, nitrogen and oxygen have gained considerable interest in the fields of forensic science and food authentication. Natural variations in the isotopic composition of lighter elements occur due to fractionation effects, resulting in the finger printing of specific isotope ratio values that are characteristic of the origin, purity, and manufacturing processes of the products and their constituents. Forensic science uses scientific and technical methods to investigate traceable evidence of criminal acts. Stable isotope ratio mass spectrometry has been applied to numerous aspects of the forensic science. The analysis of explosives such as ammonium nitrate, gun powder and tri-nitro-toluene (TNT), cases of murder, armed robbery, drug smuggling, terrorism, arson and hit and run traffic accidents are a few of them. The main types of geological evidences in such cases are mud, soil, rocks, sand, gravel, dust particles, biological materials, organic particles and anthropogenic components. Stable isotopes are used as tools to corroborate and confirm the evidential leads in the investigation of such crimes. The variation in natural abundances of carbon and nitrogen and their isotopic ratios δ 13 C and δ 15 N can identify links between items found at crime scene with those of suspect. The paper discusses the applications of SIRMS in the field of forensic science and food adulteration research

Analysis of Rapidly Developing Low Cloud Ceilings in a Stable Environment

Science.gov (United States)

Bauman, William H., III; Barrett, Joe H., III; Case, Jonathan L.; Wheeler, Mark M.; Baggett, G. Wayne

2006-01-01

regime, being a thermodynamically "capped" environment. Occurrences of elevated low-level inversions or stable layers will be highlighted in conjunction with nights that experienced a possible development or onset of cloud ceilings below 8,000 ft. Using these criteria to narrow down the database, the AMU will then use archived IR satellite imagery for these possible events. This presentation summarizes the composite meteorological conditions for 20 daytime event days with rapid low cloud ceiling formation and 48 non-events days consisting of advection or widespread low cloud ceilings and describes two sample cases of daytime rapidly-developing low cloud ceilings. The authors will also summarize the work from the nighttime cases and describe a representative sample case from this data set.

High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples

Directory of Open Access Journals (Sweden)

T. K. Bauska

2014-11-01

Full Text Available An important constraint on mechanisms of past carbon cycle variability is provided by the stable isotopic composition of carbon in atmospheric carbon dioxide (δ13C-CO2 trapped in polar ice cores, but obtaining very precise measurements has proven to be a significant analytical challenge. Here we describe a new technique to determine the δ13C of CO2 at very high precision, as well as measuring the CO2 and N2O mixing ratios. In this method, ancient air is extracted from relatively large ice samples (~400 g with a dry-extraction "ice grater" device. The liberated air is cryogenically purified to a CO2 and N2O mixture and analyzed with a microvolume-equipped dual-inlet IRMS (Thermo MAT 253. The reproducibility of the method, based on replicate analysis of ice core samples, is 0.02‰ for δ13C-CO2 and 2 ppm and 4 ppb for the CO2 and N2O mixing ratios, respectively (1σ pooled standard deviation. Our experiments show that minimizing water vapor pressure in the extraction vessel by housing the grating apparatus in a ultralow-temperature freezer (−60 °C improves the precision and decreases the experimental blank of the method to −0.07 ± 0.04‰. We describe techniques for accurate calibration of small samples and the application of a mass-spectrometric method based on source fragmentation for reconstructing the N2O history of the atmosphere. The oxygen isotopic composition of CO2 is also investigated, confirming previous observations of oxygen exchange between gaseous CO2 and solid H2O within the ice archive. These data offer a possible constraint on oxygen isotopic fractionation during H2O and CO2 exchange below the H2O bulk melting temperature.

Hydra meiosis reveals unexpected conservation of structural synaptonemal complex proteins across metazoans

OpenAIRE

Fraune, Johanna; Alsheimer, Manfred; Volff, Jean-Nicolas; Busch, Karoline; Fraune, Sebastian; Bosch, Thomas C. G.; Benavente, Ricardo

2012-01-01

The synaptonemal complex (SC) is a key structure of meiosis, mediating the stable pairing (synapsis) of homologous chromosomes during prophase I. Its remarkable tripartite structure is evolutionarily well conserved and can be found in almost all sexually reproducing organisms. However, comparison of the different SC protein components in the common meiosis model organisms Saccharomyces cerevisiae, Arabidopsis thaliana, Caenorhabditis elegans, Drosophila melanogaster, and Mus musculus revealed...

Use of flow cytometry and stable isotope analysis to determine phytoplankton uptake of wastewater derived ammonium in a nutrient-rich river

Science.gov (United States)

Schmidt, Calla M.; Kraus, Tamara; Young, Megan B.; Kendall, Carol

2018-01-01

Anthropogenic alteration of the form and concentration of nitrogen (N) in aquatic ecosystems is widespread. Understanding availability and uptake of different N sources at the base of aquatic food webs is critical to establishment of effective nutrient management programs. Stable isotopes of N (14N, 15N) are often used to trace the sources of N fueling aquatic primary production, but effective use of this approach requires obtaining a reliable isotopic ratio for phytoplankton. In this study, we tested the use of flow cytometry to isolate phytoplankton from bulk particulate organic matter (POM) in a portion of the Sacramento River, California, during river-scale nutrient manipulation experiments that involved halting wastewater discharges high in ammonium (NH4+). Field samples were collected using a Lagrangian approach, allowing us to measure changes in phytoplankton N source in the presence and absence of wastewater-derived NH4+. Comparison of δ15N-POM and δ15N-phytoplankton (δ15N-PHY) revealed that their δ15N values followed broadly similar trends. However, after 3 days of downstream travel in the presence of wastewater treatment plant (WWTP) effluent, δ15N-POM and δ15N-PHY in the Sacramento River differed by as much as 7 ‰. Using a stable isotope mixing model approach, we estimated that in the presence of effluent between 40 and 90 % of phytoplankton N was derived from NH4+ after 3 days of downstream transport. An apparent gradual increase over time in the proportion of NH4+ in the phytoplankton N pool suggests that either very low phytoplankton growth rates resulted in an N turnover time that exceeded the travel time sampled during this study, or a portion of the phytoplankton community continued to access nitrate even in the presence of elevated NH4+ concentrations.

Use of flow cytometry and stable isotope analysis to determine phytoplankton uptake of wastewater derived ammonium in a nutrient-rich river

Directory of Open Access Journals (Sweden)

C. M. Schmidt

2018-01-01

Full Text Available Anthropogenic alteration of the form and concentration of nitrogen (N in aquatic ecosystems is widespread. Understanding availability and uptake of different N sources at the base of aquatic food webs is critical to establishment of effective nutrient management programs. Stable isotopes of N (14N, 15N are often used to trace the sources of N fueling aquatic primary production, but effective use of this approach requires obtaining a reliable isotopic ratio for phytoplankton. In this study, we tested the use of flow cytometry to isolate phytoplankton from bulk particulate organic matter (POM in a portion of the Sacramento River, California, during river-scale nutrient manipulation experiments that involved halting wastewater discharges high in ammonium (NH4+. Field samples were collected using a Lagrangian approach, allowing us to measure changes in phytoplankton N source in the presence and absence of wastewater-derived NH4+. Comparison of δ15N-POM and δ15N-phytoplankton (δ15N-PHY revealed that their δ15N values followed broadly similar trends. However, after 3 days of downstream travel in the presence of wastewater treatment plant (WWTP effluent, δ15N-POM and δ15N-PHY in the Sacramento River differed by as much as 7 ‰. Using a stable isotope mixing model approach, we estimated that in the presence of effluent between 40 and 90 % of phytoplankton N was derived from NH4+ after 3 days of downstream transport. An apparent gradual increase over time in the proportion of NH4+ in the phytoplankton N pool suggests that either very low phytoplankton growth rates resulted in an N turnover time that exceeded the travel time sampled during this study, or a portion of the phytoplankton community continued to access nitrate even in the presence of elevated NH4+ concentrations.

Use of flow cytometry and stable isotope analysis to determine phytoplankton uptake of wastewater derived ammonium in a nutrient-rich river

Science.gov (United States)

Schmidt, Calla M.; Kraus, Tamara E. C.; Young, Megan B.; Kendall, Carol

2018-01-01

Anthropogenic alteration of the form and concentration of nitrogen (N) in aquatic ecosystems is widespread. Understanding availability and uptake of different N sources at the base of aquatic food webs is critical to establishment of effective nutrient management programs. Stable isotopes of N (14N, 15N) are often used to trace the sources of N fueling aquatic primary production, but effective use of this approach requires obtaining a reliable isotopic ratio for phytoplankton. In this study, we tested the use of flow cytometry to isolate phytoplankton from bulk particulate organic matter (POM) in a portion of the Sacramento River, California, during river-scale nutrient manipulation experiments that involved halting wastewater discharges high in ammonium (NH4+). Field samples were collected using a Lagrangian approach, allowing us to measure changes in phytoplankton N source in the presence and absence of wastewater-derived NH4+. Comparison of δ15N-POM and δ15N-phytoplankton (δ15N-PHY) revealed that their δ15N values followed broadly similar trends. However, after 3 days of downstream travel in the presence of wastewater treatment plant (WWTP) effluent, δ15N-POM and δ15N-PHY in the Sacramento River differed by as much as 7 ‰. Using a stable isotope mixing model approach, we estimated that in the presence of effluent between 40 and 90 % of phytoplankton N was derived from NH4+ after 3 days of downstream transport. An apparent gradual increase over time in the proportion of NH4+ in the phytoplankton N pool suggests that either very low phytoplankton growth rates resulted in an N turnover time that exceeded the travel time sampled during this study, or a portion of the phytoplankton community continued to access nitrate even in the presence of elevated NH4+ concentrations.

Results of field studies on 90SR and stable SR soil-to-plant transfer

International Nuclear Information System (INIS)

Gerzabek, M.H.; Artner, C.; Horak, O.; Mueck, K.

1992-01-01

In 1987 and 1988 at 35 sites plants ready to harvest and the corresponding soils (0 - 20 cm) were collected for 90 Sr and stable strontium analyses. Sample preparation and measurement led to a detection limit of 0.008 Bq 90 Sr kg -1 . The 90 Sr-contamination of Austrian soils ranged from 396 to 1998 Bq m -2 . Known from literature the contribution of the Chernobyl fallout amounted to app. 25 % of the total contamination. Stable strontium contents of the soils were between 6 and 62.5 mg kg -1 . Bariumtriethanolamine extracted 17.7 to 62.3 % of the total stable Sr in soil. 90 Sr-concentrations in cereal grains ranged from 0.03 to 0.67 Bq kg -1 (fresh wight) for maize and barley, respectively. The values for other foodstuff were between 0.15 (white cabbage) and 0.91 Bq kg -1 (spinach). Stable strontium contents were between 0.079 mg kg -1 (maize) and 72.5 mg kg -1 (celery shoot). The following mean 90 Sr soil-to-plant transfer factors for cereal grains were obtained: 0.010 (maize), 0.097 (rye), 0.049 (wheat), 0.095 (barley). Transfer factors for straw were up to 50 times higher (maize). The transfer of 90 Sr into vegetables and potatoes reached the same order of magnitude compared to the cereals. In all cases soil-to-plant transfer of stable Sr was clearly lower up to 60 % of the respective values for 90 Sr. Thus natural stable strontium is less plant available than 90 Sr. The influence of soil parameters on the 90 Sr transfer into plants was examinated by correlation analyses. Increasing exchangeable calcium contents of the soils resulted in a significant reduction of Sr soil-to-barley straw transfer. (authors)

Highly stable silica-coated manganese ferrite nanoparticles as high-efficacy T2 contrast agents for magnetic resonance imaging

Science.gov (United States)

Ahmad, Ashfaq; Bae, Hongsub; Rhee, Ilsu

2018-05-01

Highly stable silica-coated manganese ferrite nanoparticles were fabricated for application as magnetic resonance imagining (MRI) contrast agents. The manganese ferrite nanoparticles were synthesized using a hydrothermal technique and coated with silica. The particle size was investigated using transmission electron microscopy and was found to be 40-60 nm. The presence of the silica coating on the particle surface was confirmed by Fourier transform infrared spectroscopy. The crystalline structure was investigated by X-ray diffraction, and the particles were revealed to have an inverse spinel structure. Superparamagnetism was confirmed by the magnetic hysteresis curves obtained using a vibrating sample magnetometer. The efficiency of the MRI contrast agents was investigated by using aqueous solutions of the particles in a 4.7 T MRI scanner. The T1 and T2 relaxivities of the particles were 1.42 and 60.65 s-1 mM-1, respectively, in water. The ratio r2/r1 was 48.91, confirming that the silica-coated manganese ferrite nanoparticles were suitable high-efficacy T2 contrast agents.

Clipperton Atoll Core 2B Stable Isotope (delta 13C, delta 18O) Data for 1893 to 1994

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — 101 year stable isotope record from P. lobata, core 4B, Clipperton Atoll, eastern Pacific. Sampling at annual and 12/year resolution, files clipperton.4B.iso.txt and...

Clipperton Atoll Core 3C Stable Isotope (delta 13C, delta 18O) Data for 1893 to 1994

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — 101 year stable isotope record from P. lobata, core 4B, Clipperton Atoll, eastern Pacific. Sampling at annual and 12/year resolution, files clipperton.4B.iso.txt and...

Clipperton Atoll Core 4B Stable Isotope (delta 13C, delta 18O) Data for 1893 to 1994

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — 101 year stable isotope record from P. lobata, core 4B, Clipperton Atoll, eastern Pacific. Sampling at annual and 12/year resolution, files clipperton.4B.iso.txt and...

Exact simulation of max-stable processes.

Science.gov (United States)

Dombry, Clément; Engelke, Sebastian; Oesting, Marco

2016-06-01

Max-stable processes play an important role as models for spatial extreme events. Their complex structure as the pointwise maximum over an infinite number of random functions makes their simulation difficult. Algorithms based on finite approximations are often inexact and computationally inefficient. We present a new algorithm for exact simulation of a max-stable process at a finite number of locations. It relies on the idea of simulating only the extremal functions, that is, those functions in the construction of a max-stable process that effectively contribute to the pointwise maximum. We further generalize the algorithm by Dieker & Mikosch (2015) for Brown-Resnick processes and use it for exact simulation via the spectral measure. We study the complexity of both algorithms, prove that our new approach via extremal functions is always more efficient, and provide closed-form expressions for their implementation that cover most popular models for max-stable processes and multivariate extreme value distributions. For simulation on dense grids, an adaptive design of the extremal function algorithm is proposed.

Bacterioplankton communities of Crater Lake, OR: Dynamic changes with euphotic zone food web structure and stable deep water populations

Science.gov (United States)

Urbach, E.; Vergin, K.L.; Larson, G.L.; Giovannoni, S.J.

2007-01-01

The distribution of bacterial and archaeal species in Crater Lake plankton varies dramatically over depth and with time, as assessed by hybridization of group-specific oligonucleotides to RNA extracted from lakewater. Nonmetric, multidimensional scaling (MDS) analysis of relative bacterial phylotype densities revealed complex relationships among assemblages sampled from depth profiles in July, August and September of 1997 through 1999. CL500-11 green nonsulfur bacteria (Phylum Chloroflexi) and marine Group I crenarchaeota are consistently dominant groups in the oxygenated deep waters at 300 and 500 m. Other phylotypes found in the deep waters are similar to surface and mid-depth populations and vary with time. Euphotic zone assemblages are dominated either by ??-proteobacteria or CL120-10 verrucomicrobia, and ACK4 actinomycetes. MDS analyses of euphotic zone populations in relation to environmental variables and phytoplankton and zooplankton population structures reveal apparent links between Daphnia pulicaria zooplankton population densities and microbial community structure. These patterns may reflect food web interactions that link kokanee salmon population densities to community structure of the bacterioplankton, via fish predation on Daphnia with cascading consequences to Daphnia bacterivory and predation on bacterivorous protists. These results demonstrate a stable bottom-water microbial community. They also extend previous observations of food web-driven changes in euphotic zone bacterioplankton community structure to an oligotrophic setting. ?? 2007 Springer Science+Business Media B.V.

Cosmic-ray-produced stable nuclides: various production rates and their implications

International Nuclear Information System (INIS)

Reedy, R.C.

1981-01-01

The rates for a number of reactions producing certain stable nuclides, such as 3 He and 4 He, and fission in the moon are calculated for galactic-cosmic-ray particles and for solar protons. Solar-proton-induced reactions with bromine usually are not an important source of cosmogenic Kr isotopes. The 130 Ba(n,p) reaction cannot account for the undercalculation of 130 Xe production rates. Calculated production rates of 15 N, 13 C, and 2 H agree fairly well with rates inferred from measured excesses of these isotopes in samples with long exposure ages. Cosmic-ray-induced fission of U and Th can produce significant amounts of fission tracks and of 86 Kr, 134 Xe, and 136 Xe, especially in samples with long exposures to cosmic-ray particles

Experimental assessment of the energy consumption of urban rail vehicles during stabling hours: Influence of ambient temperature

International Nuclear Information System (INIS)

Powell, J.P.; González-Gil, A.; Palacin, R.

2014-01-01

Urban rail has widely recognised potential to reduce congestion and air pollution in metropolitan areas, given its high capacity and environmental performance. Nevertheless, growing capacity demands and rising energy costs may call for significant energy efficiency improvements in such systems. Energy consumed by stabled rolling stock has been traditionally overlooked in the scientific literature in favour of analysing traction loads, which generally account for the largest share of this consumption. Thus, this paper presents the methodology and results of an experimental investigation that aimed to assess the energy use of stabled vehicles in the Tyne and Wear Metro system (UK). It is revealed that approximately 11% of the rolling stock's total energy consumption is due to the operation of on-board auxiliaries when stabled, and investigation of these loads is therefore a worthwhile exercise. Heating is responsible for the greatest portion of this energy, and an empirical correlation between ambient temperature and power drawn is given. This could prove useful for a preliminary evaluation of further energy saving measures in this area. Even though this investigation focused on a particular metro system in a relatively cold region, its methodology may also be valid for other urban and main line railways operating in different climate conditions. - Highlights: •Energy use of stabled vehicles in an actual metro system is experimentally examined. •Stabling hours account for about 11% of the vehicles' total energy consumption. •Heating is the major consumer during stabling hours. •An empirical correlation between ambient temperature and power drawn is derived. •The methodology described may also be applied to other urban and main line railways

Air-stable n-type doping of graphene from overlying Si3N4 film

International Nuclear Information System (INIS)

Wang, Zegao; Li, Pingjian; Chen, Yuanfu; Liu, Jingbo; Qi, Fei; Tian, Hongjun; Zheng, Binjie; Zhou, Jinhao

2014-01-01

In this study, we report a facile method to obtain air-stable n-type graphene by plasma-enhanced chemical vapor depositing Si 3 N 4 film on the surface of graphene. We have demonstrated that the overlying Si 3 N 4 film can not only act as the penetration-barrier against H 2 O and O 2 adsorbed on the graphene surface, but also cause an effective n-type doping due to the amine groups at the interface of graphene/Si 3 N 4 . Furthermore, the studies reveal that the Dirac point of graphene can be modulated by the thickness of Si 3 N 4 film, which is due to competing effects of Si 3 N 4 -induced doping (n-type) and penetrating H 2 O (O 2 )-induced doping (p-type). We expect this method to be used for obtaining stable n-type graphene field-effect transistors in air, which will be widely used in graphene electronic devices.

Diet of spotted bats (Euderma maculatum) in Arizona as indicated by fecal analysis and stable isotopes

Science.gov (United States)

We assessed diet of spotted bats (Euderma maculatum (J.A. Allen, 1891)) by visual analysis of bat feces and stable carbon (δ13C) and nitrogen (δ15N) isotope analysis of bat feces, wing, hair, and insect prey. We collected 33 fecal samples from spotted bats and trapped 3755 insect...

Impact of contamination and pre-treatment on stable carbon and nitrogen isotopic composition of charred plant remains.

Science.gov (United States)

Vaiglova, Petra; Snoeck, Christophe; Nitsch, Erika; Bogaard, Amy; Lee-Thorp, Julia

2014-12-15

Stable isotope analysis of archaeological charred plants has become a useful tool for interpreting past agricultural practices and refining ancient dietary reconstruction. Charred material that lay buried in soil for millennia, however, is susceptible to various kinds of contamination, whose impact on the grain/seed isotopic composition is poorly understood. Pre-treatment protocols have been adapted in distinct forms from radiocarbon dating, but insufficient research has been carried out on evaluating their effectiveness and necessity for stable carbon and nitrogen isotope analysis. The effects of previously used pre-treatment protocols on the isotopic composition of archaeological and modern sets of samples were investigated. An archaeological sample was also artificially contaminated with carbonates, nitrates and humic acid and subjected to treatment aimed at removing the introduced contamination. The presence and removal of the contamination were investigated using Fourier transform infrared spectroscopy (FTIR) and δ(13)C and δ(15)N values. The results show a ca 1‰ decrease in the δ(15)N values of archaeological charred plant material caused by harsh acid treatments and ultra-sonication. This change is interpreted as being caused by mechanical distortion of the grains/seeds rather than by the removal of contamination. Furthermore, specific infrared peaks have been identified that can be used to detect the three types of contaminants studied. We argue that it is not necessary to try to remove humic acid contamination for stable isotope analysis. The advantages and disadvantages of crushing the grains/seeds before pre-treatment are discussed. We recommend the use of an acid-only procedure (0.5 M HCl for 30 min at 80 °C followed by three rinses in distilled water) for cleaning charred plant remains. This study fills an important gap in plant stable isotope research that will enable future researchers to evaluate potential sources of isotopic change and pre

The carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica

International Nuclear Information System (INIS)

Lyons, W.B.; Leslie, D.L.; Harmon, R.S.; Neumann, K.; Welch, K.A.; Bisson, K.M.; McKnight, D.M.

2013-01-01

Highlights: ► δ 13 C-DIC reported from McMurdo Dry Valleys, Antarctica, streams. ► Stream water δ 13 C PDB values range −9.4‰ to +5.1‰, largely inorganic in character. ► Atmospheric exchange is the dominant control on δ 13 C-DIC. - Abstract: The McMurdo Dry Valleys region of Antarctica is the largest ice-free region on the continent. This study reports the first C stable isotope measurements for dissolved inorganic C present in ephemeral streams in four dry valleys that flow for four to twelve weeks during the austral summer. One of these valleys, Taylor Valley, has been the focus of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) program since 1993. Within Taylor Valley, numerous ephemeral streams deliver water to three perennially ice-covered, closed-basin lakes: Lake Fryxell, Lake Hoare, and Lake Bonney. The Onyx River in the Wright Valley, the longest river in Antarctica, flows for 40 km from the Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda. Streamflow in the McMurdo Dry Valley streams is produced primarily from glacial melt, as there is no overland flow. However, hyporheic zone exchange can be a major hydrogeochemical process in these streams. Depending on landscape position, these streams vary in gradient, channel substrate, biomass abundance, and hyporheic zone extent. This study sampled streams from Taylor, Wright, Garwood, and Miers Valleys and conducted diurnal sampling of two streams of different character in Taylor Valley. In addition, transect sampling was undertaken of the Onyx River in Wright Valley. The δ 13 C PDB values from these streams span a range of greater than 14‰, from −9.4‰ to +5.1‰, with the majority of samples falling between −3‰ and +2‰, suggesting that the C stable isotope composition of dissolved C in McMurdo Dry Valley streams is largely inorganic in character. Because there are no vascular plants on this landscape and no groundwater input to these

Combined Stable Carbon Isotope and C/N Ratios as Indicators of Source and Fate of Organic Matter in the Bang Pa kong River Estuary, Thailand

International Nuclear Information System (INIS)

Boonphakdee, Thanomsak; Kasai, Akihide; Fujiwara, Tateki; Sawangwong, Pichan; Cheevaporn, Voravit

2007-08-01

Full text: Stable carbon isotopes and C/N ratios of particulate organic matter (POM) in suspended solids and surficial sediment were used to define the spatial and temporal variability in an anthropogenic tropical river estuary, the Bang Pa kong River Estuary. Samples were taken along salinity gradients during the four different river discharges in the beginning, high river discharge and at the end of the wet season, and low river discharge during the dry season. The values of [C/N]a ratio and d13C in the river estuary revealed significant differences from those of the offshore station. Conservative behaviors of [C/N]a and d13C in the estuary during the wet season indicated major contribution of terrigenous C3 plants derived OM. By contrast, during the dry season, marine input mainly dominated OM contribution with an evidence of anthropogenic input to the estuary. These compositions of the bulk sedimentary OM were dominated by paddy rice soils and marine derived OM during the wet and dry seasons, respectively. These results show that the combined stable carbon isotopes and C/N ratios can be used to identify the source and fate of OM even in a river estuary. This tool will be useful to achieve sustainable management in coastal zone

Evaluation of passive sampling of gaseous mercury using different sorbing materials.

Science.gov (United States)

Lin, Huiming; Zhang, Wei; Deng, Chunyan; Tong, Yingdong; Zhang, Qianggong; Wang, Xuejun

2017-06-01

Atmospheric mercury monitoring is essential because of its potential human health and ecological impacts. Current automated monitoring systems include limitations such as high cost, complicated configuration, and electricity requirements. Passive samplers require no electric power and are more appropriate for screening applications and long-term monitoring. Sampling rate is a major factor to evaluate the performance of a passive sampler. In this study, laboratory experiments were carried out using an exposure chamber to search for high efficiency sorbents for gaseous mercury. Four types of sorbents, including sulfur-impregnated carbon (SIC), chlorine-impregnated carbon (CIC), bromine-impregnated carbon (BIC), and gold-coated sand (GCS) were evaluated under a wide range of meteorological parameters, including temperature, relative humidity, and wind speed. The results showed that the four sorbents all have a high sampling rate above 0.01 m 3 g -1  day -1 , and wind speed has a positive correlation with the sampling rate. Under different temperature and relative humidity, the sampling rate of SIC keeps stable. The sampling rate of CIC and BIC shows a negative correlation with temperature, and GCS is influenced by all the three meteorological factors. Furthermore, long-term experiments were carried out to investigate the uptake capacity of GCS and SIC. Uptake curves show that the mass amount of sorbent in a passive sampler can influence uptake capacity. In the passive sampler, 0.9 g SIC or 0.9 g GCS can achieve stable uptake efficiency for at least 110 days with gaseous mercury concentration at or below 2 ng/m 3 . For mercury concentration at or below 21 ng/m 3 , 0.9 g SIC can maintain stable uptake efficiency for 70 days, and 0.9 g GCS can maintain stability for 45 days.

Multi-saline sample distillation apparatus for hydrogen isotope analyses : design and accuracy

Science.gov (United States)

Hassan, Afifa Afifi

1981-01-01

A distillation apparatus for saline water samples was designed and tested. Six samples may be distilled simultaneously. The temperature was maintained at 400 C to ensure complete dehydration of the precipitating salts. Consequently, the error in the measured ratio of stable hydrogen isotopes resulting from incomplete dehydration of hydrated salts during distillation was eliminated. (USGS)

Multivariate Stable Isotope Analysis to Determine Linkages between Benzocaine Seizures

Science.gov (United States)

Kemp, H. F.; Meier-Augenstein, W.; Collins, M.; Salouros, H.; Cunningham, A.; Harrison, M.

2012-04-01

distribution network. More than 40 Benzocaine samples comprising both seized and control samples were analysed by two stable isotope forensic laboratories in two different countries (Australia and Scotland) to assess intra-lab reproducibility as well as inter-lab repeatability of measured stable isotope abundance values.

Pleistocene paleo-groundwater as a pristine fresh water resource in southern Germany – evidence from stable and radiogenic isotopes

International Nuclear Information System (INIS)

Geldern, Robert van; Baier, Alfons; Subert, Hannah L.; Kowol, Sigrid; Balk, Laura; Barth, Johannes A.C.

2014-01-01

Shallow groundwater aquifers are often influenced by anthropogenic contaminants or increased nutrient levels. In contrast, deeper aquifers hold potentially pristine paleo-waters that are not influenced by modern recharge. They thus represent important water resources, but their recharge history is often unknown. In this study groundwater from two aquifers in southern Germany were analyzed for their hydrogen and oxygen stable isotope compositions. One sampling campaign targeted the upper aquifer that is actively recharged by modern precipitation, whereas the second campaign sampled the confined, deep Benkersandstein aquifer. The groundwater samples from both aquifers were compared to the local meteoric water line to investigate sources and conditions of groundwater recharge. In addition, the deep groundwater was dated by tritium and radiocarbon analyses. Stable and radiogenic isotope data indicate that the deep-aquifer groundwater was not part of the hydrological water cycle in the recent human history. The results show that the groundwater is older than ∼20,000 years and most likely originates from isotopically depleted melt waters of the Pleistocene ice age. Today, the use of this aquifer is strictly regulated to preserve the pristine water. Clear identification of such non-renewable paleo-waters by means of isotope geochemistry will help local water authorities to enact and justify measures for conservation of these valuable resources for future generations in the context of a sustainable water management. - Highlights: • Groundwater from deep aquifer identified as paleo-water with age over 20,000 years. • Low stable isotope values indicate recharge during Pleistocene. • Shallow aquifer mirrors stable isotope signature of average modern precipitation. • Identification of non-renewable paleo-waters enhance sustainable water management. • Strict protection measures of authorities justified by isotope geochemistry

Stable carbon isotope fractionation in pollen of Atlas cedar: first steps towards a new palaeoecological proxy for Northwest Africa

Science.gov (United States)

Bell, Benjamin; Fletcher, William; Ryan, Peter; Grant, Helen; Ilmen, Rachid

2016-04-01

Analysis of stable carbon isotopes can provide information on climate and the environmental conditions at different growth stages of the plant, both past and present. Carbon isotope discrimination in plant tissue is already well understood, and can be used as a drought stress indicator for semi-arid regions. Stable carbon isotope ratios measured directly on pollen provides the potential for the development of long-term environmental proxies (spanning thousands of years), as pollen is well preserved in the environment. Atlas Cedar (Cedrus atlantica Endl. Manetti ex Carrière), is an ideal test case to develop a pollen stable carbon isotope proxy. The tree grows across a wide altitudinal and climatic range and is extremely sensitive to moisture availability. The pollen is abundant, and easily identifiable to the species level in pollen analysis because different cedar species are geographically confined to different regions of the world. In 2015 we sampled 76 individual cedar trees across latitudinal, altitudinal and environmental gradients, highly focused on the Middle Atlas region of Morocco, with 25 additional samples from botanical gardens across Europe and the US to extend these gradients. Here, we report new stable carbon isotope data from pollen, leaf and stem wood from these samples with a view to assessing and quantifying species-specific fractionation effects associated with pollen production. The isotopic response of individual trees at local and wider geographical scales to altitude and climatic conditions is presented. This research forms part of an ongoing PhD project working to develop and calibrate a modern carbon isotope proxy in Atlas cedar pollen, which can ultimately be applied to fossil sequences and complement existing multi-proxy records (e.g. pollen analysis in lake sediments, tree-rings).

Pleistocene paleo-groundwater as a pristine fresh water resource in southern Germany – evidence from stable and radiogenic isotopes

Energy Technology Data Exchange (ETDEWEB)

Geldern, Robert van, E-mail: robert.van.geldern@fau.de [Friedrich-Alexander-University Erlangen-Nuremberg (FAU), Department of Geography and Geosciences, GeoZentrum Nordbayern, Schlossgarten 5, 91054 Erlangen (Germany); Baier, Alfons; Subert, Hannah L. [Friedrich-Alexander-University Erlangen-Nuremberg (FAU), Department of Geography and Geosciences, GeoZentrum Nordbayern, Schlossgarten 5, 91054 Erlangen (Germany); Kowol, Sigrid [Erlanger Stadtwerke AG, Äußere Brucker Str. 33, 91052 Erlangen (Germany); Balk, Laura; Barth, Johannes A.C. [Friedrich-Alexander-University Erlangen-Nuremberg (FAU), Department of Geography and Geosciences, GeoZentrum Nordbayern, Schlossgarten 5, 91054 Erlangen (Germany)

2014-10-15

Shallow groundwater aquifers are often influenced by anthropogenic contaminants or increased nutrient levels. In contrast, deeper aquifers hold potentially pristine paleo-waters that are not influenced by modern recharge. They thus represent important water resources, but their recharge history is often unknown. In this study groundwater from two aquifers in southern Germany were analyzed for their hydrogen and oxygen stable isotope compositions. One sampling campaign targeted the upper aquifer that is actively recharged by modern precipitation, whereas the second campaign sampled the confined, deep Benkersandstein aquifer. The groundwater samples from both aquifers were compared to the local meteoric water line to investigate sources and conditions of groundwater recharge. In addition, the deep groundwater was dated by tritium and radiocarbon analyses. Stable and radiogenic isotope data indicate that the deep-aquifer groundwater was not part of the hydrological water cycle in the recent human history. The results show that the groundwater is older than ∼20,000 years and most likely originates from isotopically depleted melt waters of the Pleistocene ice age. Today, the use of this aquifer is strictly regulated to preserve the pristine water. Clear identification of such non-renewable paleo-waters by means of isotope geochemistry will help local water authorities to enact and justify measures for conservation of these valuable resources for future generations in the context of a sustainable water management. - Highlights: • Groundwater from deep aquifer identified as paleo-water with age over 20,000 years. • Low stable isotope values indicate recharge during Pleistocene. • Shallow aquifer mirrors stable isotope signature of average modern precipitation. • Identification of non-renewable paleo-waters enhance sustainable water management. • Strict protection measures of authorities justified by isotope geochemistry.

Stable isotope fractionation at a glacial hydrothermal field: implications for biogeochemistry and biosignatures on Mars

Science.gov (United States)

Cousins, C.; Bowden, R.; Fogel, M.; Cockell, C.; Crawford, I.; Gunn, M.; Karlsson, M. T.; Thorsteinsson, T.

2012-12-01

Hydrothermal environments that arise through the interaction between volcanogenic heat and glacial ice are ideal sites for understanding microbial biogeochemical processes on Earth, and also potentially on Mars where similar volcano-cryosphere interactions are thought to have occurred in the past. The Kverkfjöll subglacial basaltic volcano in central Iceland is geographically isolated, with little influence from flora, fauna, and human activity. Major environmental inputs include geothermal heat, meltwater from ice and snow, and outgassing of CO2, H2S, and SO2. Large physiochemical gradients exist, from steaming fumaroles and boiling hydrothermal pools, to frozen geothermal ground and glacial ice. Stable isotope measurements of total organic carbon, total sulphur, and total nitrogen were coupled with metagenomic analysis of the residing microbial communities, with the aim to identify biogeochemical relationships and processes operating within the Kverkfjöll geothermal environment, and also to identify any isotopic biosignatures that could be preserved within geothermal sediments. This study focused on a variety of samples taken along a hot spring stream that fed into a large ice-confined geothermal lake. Samples analysed range from unconsolidated hot spring sediments, well-developed microbial mats, and dissolved sulphate from hot spring fluids. From the anoxic spring source, the stream water increases in dissolved oxygen, decreases in temperature, yet maintains a pH of ~4. The spring environment is dominated by dissolved sulphate (~2.3 mM), with lower levels of nitrate (~50 μM), phosphorus (~5μM), and ammonium (~1.5 μM). Stable S isotope analysis reveals a fractionation of ~3.2 ‰ between sediment sulphide (as pyrite; δ34S ~0‰), and dissolved water sulphate (δ34S ~3.2 ‰) consistently along the hot spring stream, indicating the presence of an active sulphur cycle, although not one dominated by sulphate reduction (e.g. very negative sulphide δ34S). This

Stable isotopes of C and N reveal habitat dependent dietary overlap between native and introduced turtles Pseudemys rubriventris and Trachemys scripta.

Science.gov (United States)

Pearson, Steven H; Avery, Harold W; Kilham, Susan S; Velinsky, David J; Spotila, James R

2013-01-01

Habitat degradation and species introductions are two of the leading causes of species declines on a global scale. Invasive species negatively impact native species through predation and competition for limited resources. The impacts of invasive species may be increased in habitats where habitat degradation is higher due to reductions of prey abundance and distribution. Using stable isotope analyses and extensive measurements of resource availability we determined how resource availability impacts the long term carbon and nitrogen assimilation of the invasive red-eared slider turtle (Trachemys scripta elegans) and a native, threatened species, the red-bellied turtle (Pseudemys rubriventris) at two different freshwater wetland complexes in Pennsylvania, USA. At a larger wetland complex with greater vegetative species richness and diversity, our stable isotope analyses showed dietary niche partitioning between species, whereas analyses from a smaller wetland complex with lower vegetative species richness and diversity showed significant dietary niche overlap. Determining the potential for competition between these two turtle species is important to understanding the ecological impacts of red-eared slider turtles in wetland habitats. In smaller wetlands with increased potential for competition between native turtles and invasive red-eared slider turtles we expect that when shared resources become limited, red-eared slider turtles will negatively impact native turtle species leading to long term population declines. Protection of intact wetland complexes and the reduction of introduced species populations are paramount to preserving populations of native species.

Stable isotopes of C and N reveal habitat dependent dietary overlap between native and introduced turtles Pseudemys rubriventris and Trachemys scripta.

Directory of Open Access Journals (Sweden)

Steven H Pearson

Full Text Available Habitat degradation and species introductions are two of the leading causes of species declines on a global scale. Invasive species negatively impact native species through predation and competition for limited resources. The impacts of invasive species may be increased in habitats where habitat degradation is higher due to reductions of prey abundance and distribution. Using stable isotope analyses and extensive measurements of resource availability we determined how resource availability impacts the long term carbon and nitrogen assimilation of the invasive red-eared slider turtle (Trachemys scripta elegans and a native, threatened species, the red-bellied turtle (Pseudemys rubriventris at two different freshwater wetland complexes in Pennsylvania, USA. At a larger wetland complex with greater vegetative species richness and diversity, our stable isotope analyses showed dietary niche partitioning between species, whereas analyses from a smaller wetland complex with lower vegetative species richness and diversity showed significant dietary niche overlap. Determining the potential for competition between these two turtle species is important to understanding the ecological impacts of red-eared slider turtles in wetland habitats. In smaller wetlands with increased potential for competition between native turtles and invasive red-eared slider turtles we expect that when shared resources become limited, red-eared slider turtles will negatively impact native turtle species leading to long term population declines. Protection of intact wetland complexes and the reduction of introduced species populations are paramount to preserving populations of native species.

Assessing Sources of Human Methylmercury Exposure Using Stable Mercury Isotopes

DEFF Research Database (Denmark)

Li, Miling; Sherman, Laura S; Blum, Joel D

2014-01-01

Seafood consumption is the primary route of methylmercury (MeHg) exposure for most populations. Inherent uncertainties in dietary survey data point to the need for an empirical tool to confirm exposure sources. We therefore explore the utility of Hg stable isotope ratios in human hair as a new...... method for discerning MeHg exposure sources. We characterized Hg isotope fractionation between humans and their diets using hair samples from Faroese whalers exposed to MeHg predominantly from pilot whales. We observed an increase of 1.75‰ in δ(202)Hg values between pilot whale muscle tissue and Faroese...... whalers' hair but no mass-independent fractionation. We found a similar offset in δ(202)Hg between consumed seafood and hair samples from Gulf of Mexico recreational anglers who are exposed to lower levels of MeHg from a variety of seafood sources. An isotope mixing model was used to estimate individual...

Analysing Stable Time Series

National Research Council Canada - National Science Library

Adler, Robert

1997-01-01

We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

Tukey max-stable processes for spatial extremes

KAUST Repository

Xu, Ganggang; Genton, Marc G.

2016-01-01

We propose a new type of max-stable process that we call the Tukey max-stable process for spatial extremes. It brings additional flexibility to modeling dependence structures among spatial extremes. The statistical properties of the Tukey max

Multisample conversion of water to hydrogen by zinc for stable isotope determination

Science.gov (United States)

Kendall, C.; Coplen, T.B.

1985-01-01

Two techniques for the conversion of water to hydrogen for stable isotope ratio determination have been developed that are especially suited for automated multisample analysis. Both procedures involve reaction of zinc shot with a water sample at 450 ??C. in one method designed for water samples in bottles, the water is put in capillaries and is reduced by zinc in reaction vessels; overall savings in sample preparation labor of 75% have been realized over the standard uranium reduction technique. The second technique is for waters evolved under vacuum and is a sealed-tube method employing 9 mm o.d. quartz tubing. Problems inherent with zinc reduction include surface inhomogeneity of the zinc and exchange of hydrogen both with the zinc and with the glass walls of the vessels. For best results, water/zinc and water/glass surface area ratios of vessels should be kept as large as possible.

Sample preparations for spark source mass spectrography

International Nuclear Information System (INIS)

Catlett, C.W.; Rollins, M.B.; Griffin, E.B.; Dorsey, J.G.

1977-10-01

Methods have been developed for the preparation of various materials for spark source mass spectrography. The essential features of these preparations (all which can provide adequate precision in a cost-effective manner) consist in obtaining spark-stable electrode sample pieces, a common matrix, a reduction of anomolous effects in the spark, the incorporation of a suitable internal standard for plate response normalization, and a reduction in time

An organic solvent-, detergent-, and thermo-stable alkaline protease from the mesophilic, organic solvent-tolerant Bacillus licheniformis 3C5.

Science.gov (United States)

Rachadech, W; Navacharoen, A; Ruangsit, W; Pongtharangkul, T; Vangnai, A S

2010-01-01

Bacillus licheniformis 3C5, isolated as mesophilic bacterium, exhibited tolerance towards a wide range of non-polar and polar organic solvents at 45 degrees C. It produced an extracellular organic solvent-stable protease with an apparent molecular mass of approximately 32 kDa. The inhibitory effect of PMSF and EDTA suggested it is likely to be an alkaline serine protease. The protease was active over abroad range of temperatures (45-70 degrees C) and pH (8-10) range with an optimum activity at pH 10 and 65 degrees C. It was comparatively stable in the presence ofa relatively high concentration (35% (v/v)) of organic solvents and various types of detergents even at a relatively high temperature (45 degrees C). The protease production by B. licheniformis 3C5 was growth-dependent. The optimization of carbon and nitrogen sources for cell growth and protease production revealed that yeast extract was an important medium component to support both cell growth and the protease production. The overall properties of the protease produced by B. licheniformis 3C5 suggested that this thermo-stable, solvent-stable, detergent-stable alkaline protease is a promising potential biocatalyst for industrial and environmental applications.

Toward a simple, repeatable, non-destructive approach to measuring stable-isotope ratios of water within tree stems

Science.gov (United States)

Raulerson, S.; Volkmann, T.; Pangle, L. A.

2017-12-01

Traditional methodologies for measuring ratios of stable isotopes within the xylem water of trees involve destructive coring of the stem. A recent approach involves permanently installed probes within the stem, and an on-site assembly of pumps, switching valves, gas lines, and climate-controlled structure for field deployment of a laser spectrometer. The former method limits the possible temporal resolution of sampling, and sample size, while the latter may not be feasible for many research groups. We present results from initial laboratory efforts towards developing a non-destructive, temporally-resolved technique for measuring stable isotope ratios within the xylem flow of trees. Researchers have used direct liquid-vapor equilibration as a method to measure isotope ratios of the water in soil pores. Typically, this is done by placing soil samples in a fixed container, and allowing the liquid water within the soil to come into isotopic equilibrium with the headspace of the container. Water can also be removed via cryogenic distillation or azeotropic distillation, with the resulting liquid tested for isotope ratios. Alternatively, the isotope ratios of the water vapor can be directly measured using a laser-based water vapor isotope analyzer. Well-established fractionation factors and the isotope ratios in the vapor phase are then used to calculate the isotope ratios in the liquid phase. We propose a setup which would install a single, removable chamber onto a tree, where vapor samples could non-destructively and repeatedly be taken. These vapor samples will be injected into a laser-based isotope analyzer by a recirculating gas conveyance system. A major part of what is presented here is in the procedure of taking vapor samples at 100% relative humidity, appropriately diluting them with completely dry N2 calibration gas, and injecting them into the gas conveyance system without inducing fractionation in the process. This methodology will be helpful in making

Feasibility Study on the Use of the Seeding Growth Technique in Producing a Highly Stable Gold Nanoparticle Colloidal System

Directory of Open Access Journals (Sweden)

Kim Han Tan

2015-01-01

Full Text Available Stable colloidal gold nanoparticles (Au NPs are synthesized successfully using a seeding growth technique. The size of the nanoparticles is determined using transmission electron microscopy (TEM, and it is observed that the size of the nanoparticles ranges from 7 to 30 nm. The TEM images and optical absorption spectra of the Au NPs reveal that the suspension is well dispersed and consistent with the particle size. The feasibility of the seeding growth technique is investigated using Turbiscan Classic MA 2000 screening stability tester. Based on the peak thickness kinetics and mean value kinetics, the backscattered light profiles indicate that the suspension is highly stable without particle sedimentation as well as negligible agglomeration. In addition, the Au NPs are proven to remain stable over a period of 2 months. Particle sedimentation eventually occurs due to the weight of nanoparticles. It is concluded that the seeding growth technique is feasible in synthesizing stable Au NPs. Controlling the stability, size and shape of Au NPs are technologically important because of the strong correlation between these parameters and the optical, electrical, and catalytic properties of the nanoparticles.

Assessment of Bacterial Degradation of Aromatic Hydrocarbons in the Environment by Analysis of Stable Carbon Isotope Fractionation

International Nuclear Information System (INIS)

Meckenstock, Rainer U.; Morasch, Barbara; Kaestner, Matthias; Vieth, Andrea; Richnow, Hans Hermann

2002-01-01

13 C/ 12 C stable carbon isotope fractionation was used to assess biodegradation in contaminated aquifers with toluene as a model compound. Different strains of anaerobic bacteria (Thauera aromatica, Geobacter metallireducens, and the sulfate-reducing strain TRM1) showed consistent 13 C/ 12 C carbon isotope fractionation with fractionation factors between αC = 1.0017 and 1.0018. In contrast, three cultures of aerobic organisms, using different mono- and dioxygenase enzyme systems to initiate toluene degradation, showed variable isotope fractionation factors of αC = 1.0027 (Pseudomonasputida strain mt-2), αC = 1.0011 (Ralstonia picketii), andαC = 1.0004 (Pseudomonas putida strain F1). The great variability of isotope fractionation between different aerobic bacterial strains suggests that interpretation of isotope data in oxic habitats can only be qualitative. A soil column was run as a model system for contaminated aquifers with toluene as the carbon source and sulfate as the electron acceptor and samples were taken at different ports along the column. Microbial toluene degradation was calculated based on the 13 C/ 12 C isotope fractionation factors of the batch culture experiments together with the observed 13 C/ 12 C isotope shifts of the residual toluene fractions. The calculated percentage of biodegradation, B, correlated well with the decreasing toluene concentrations at the sampling ports and indicated the increasing extent of biodegradation along the column. The theoretical toluene concentrations as calculated based on the isotope values matched the measured concentrations at the different sampling ports indicating that the Rayleigh equation can be used to calculate biodegradation in quasi closed systems based on measured isotope shifts. A similar attempt was performed to assess toluene degradation in a contaminated, anoxic aquifer. A transect of groundwater wells was monitored along the main direction of the groundwater flow and revealed decreasing

Stable isotopes of authigenic minerals in variably-saturated fractured tuff

International Nuclear Information System (INIS)

Weber, D.S.; Evans, D.D.

1988-11-01

Identifying stable isotope variation and mineralogical changes in fractured rock may help establish the history of climatic and geomorphological processes that might affect the isolation properties of a waste repository site. This study examines the use of the stable isotope ratios of oxygen ( 18 O/ 16 O) and carbon ( 13 C/ 12 C) in authigenic minerals as hydrogeochemical tools tracing low-temperature rock-water interaction in variably-saturated fractured stuff. Isotopic compositions of fracture-filling and rock matrix minerals in the Apache Leap tuff, near Superior, Arizona were concordant with geothermal temperatures and in equilibrium with water isotopically similar to present-day meteoric water and groundwater. Oxygen and carbon isotope ratios of fracture-filling, in unsaturated fractured tuff, displayed an isotopic gradient believed to result from near-surface isotopic enrichment due to evaporation rather than the effects of rock-water interaction. Oxygen isotope ratios of rock matrix opal samples exhibited an isotopic gradient believed to result from, leaching and reprecipitation of silica at depth. Methods and results can be used to further define primary flowpaths and the movement of water in variably-saturated fractured rock. 71 refs., 23 figs., 3 tabs

Stable isotopes of authigenic minerals in variably-saturated fractured tuff

Energy Technology Data Exchange (ETDEWEB)

Weber, D.S.; Evans, D.D.

1988-11-01

Identifying stable isotope variation and mineralogical changes in fractured rock may help establish the history of climatic and geomorphological processes that might affect the isolation properties of a waste repository site. This study examines the use of the stable isotope ratios of oxygen ({sup 18}O/{sup 16}O) and carbon ({sup 13}C/{sup 12}C) in authigenic minerals as hydrogeochemical tools tracing low-temperature rock-water interaction in variably-saturated fractured stuff. Isotopic compositions of fracture-filling and rock matrix minerals in the Apache Leap tuff, near Superior, Arizona were concordant with geothermal temperatures and in equilibrium with water isotopically similar to present-day meteoric water and groundwater. Oxygen and carbon isotope ratios of fracture-filling, in unsaturated fractured tuff, displayed an isotopic gradient believed to result from near-surface isotopic enrichment due to evaporation rather than the effects of rock-water interaction. Oxygen isotope ratios of rock matrix opal samples exhibited an isotopic gradient believed to result from, leaching and reprecipitation of silica at depth. Methods and results can be used to further define primary flowpaths and the movement of water in variably-saturated fractured rock. 71 refs., 23 figs., 3 tabs.

Carbon and Nitrogen Stable Isotope Values for Plants and Mammals in a Semi-Desert Region of Mongolia

Directory of Open Access Journals (Sweden)

Hannah Davie

2014-12-01

Full Text Available Little information exists on the isotopic signatures of plants and animals in Mongolia, limiting the application of stable isotope analysis to wildlife biology studies. Here we present plant and mammal carbon (δ 13 C and nitrogen (δ 15 N isotope values from a desert-steppe region of southeastern Mongolia. We analyzed 11 samples from 11 plant species and 93 samples from 24 mammal species across Ikh Nart Nature Reserve, and compared these numbers to isotope values reported from other areas of Mongolia. Our plant and mammal 13 C and 15 N values were similar to those from a similar arid steppe region and more enriched than those from less arid habitats. Habitat variation within and between study sites has an important infl uence on δ 13 C and δ 15 N variation. Our results supplement current knowledge of isotopic variation in Mongolia and provide a reference for future stable isotope research in Mongolia and similar Asian steppe ecosystems.

Increasing volume and complexity of pediatric epilepsy surgery with stable seizure outcome between 2008 and 2014

DEFF Research Database (Denmark)

Barba, Carmen; Specchio, Nicola; Guerrini, Renzo

2017-01-01

Objective The objective of the study was to assess common practice in pediatric epilepsy surgery in Italy between 2008 and 2014. Methods A survey was conducted among nine Italian epilepsy surgery centers to collect information on presurgical and postsurgical evaluation protocols, volumes and type...... and facilities. Significance This survey reveals an increase in volume and complexity of pediatric epilepsy surgery in Italy between 2008 and 2014, associated with a stable seizure outcome....

Combined Metabolomic Analysis of Plasma and Urine Reveals AHBA, Tryptophan and Serotonin Metabolism as Potential Risk Factors in Gestational Diabetes Mellitus (GDM

Directory of Open Access Journals (Sweden)

Miriam Leitner

2017-12-01

Full Text Available Gestational diabetes mellitus during pregnancy has severe implications for the health of the mother and the fetus. Therefore, early prediction and an understanding of the physiology are an important part of prenatal care. Metabolite profiling is a long established method for the analysis and prediction of metabolic diseases. Here, we applied untargeted and targeted metabolomic protocols to analyze plasma and urine samples of pregnant women with and without GDM. Univariate and multivariate statistical analyses of metabolomic profiles revealed markers such as 2-hydroxybutanoic acid (AHBA, 3-hydroxybutanoic acid (BHBA, amino acids valine and alanine, the glucose-alanine-cycle, but also plant-derived compounds like sitosterin as different between control and GDM patients. PLS-DA and VIP analysis revealed tryptophan as a strong variable separating control and GDM. As tryptophan is biotransformed to serotonin we hypothesized whether serotonin metabolism might also be altered in GDM. To test this hypothesis we applied a method for the analysis of serotonin, metabolic intermediates and dopamine in urine by stable isotope dilution direct infusion electrospray ionization mass spectrometry (SID-MS. Indeed, serotonin and related metabolites differ significantly between control and GDM patients confirming the involvement of serotonin metabolism in GDM. Clustered correlation coefficient visualization of metabolite correlation networks revealed the different metabolic signatures between control and GDM patients. Eventually, the combination of selected blood plasma and urine sample metabolites improved the AUC prediction accuracy to 0.99. The detected GDM candidate biomarkers and the related systemic metabolic signatures are discussed in their pathophysiological context. Further studies with larger cohorts are necessary to underpin these observations.

Stable isotope studies

International Nuclear Information System (INIS)

Ishida, T.

1992-01-01

The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

Development of routines for simultaneous in situ chemical composition and stable Si isotope ratio analysis by femtosecond laser ablation inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Frick, Daniel A., E-mail: dfrick@gfz-potsdam.de [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Schuessler, Jan A. [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Blanckenburg, Friedhelm von [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Institute of Geological Science, Freie Universität Berlin, 12249 Berlin (Germany)

2016-09-28

Stable metal (e.g. Li, Mg, Ca, Fe, Cu, Zn, and Mo) and metalloid (B, Si, Ge) isotope ratio systems have emerged as geochemical tracers to fingerprint distinct physicochemical reactions. These systems are relevant to many Earth Science questions. The benefit of in situ microscale analysis using laser ablation (LA) over bulk sample analysis is to use the spatial context of different phases in the solid sample to disclose the processes that govern their chemical and isotopic compositions. However, there is a lack of in situ analytical routines to obtain a samples' stable isotope ratio together with its chemical composition. Here, we evaluate two novel analytical routines for the simultaneous determination of the chemical and Si stable isotope composition (δ{sup 30}Si) on the micrometre scale in geological samples. In both routines, multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is combined with femtosecond-LA, where stable isotope ratios are corrected for mass bias using standard-sample-bracketing with matrix-independent calibration. The first method is based on laser ablation split stream (LASS), where the laser aerosol is split and introduced simultaneously into both the MC-ICP-MS and a quadrupole ICP-MS. The second method is based on optical emission spectroscopy using direct observation of the MC-ICP-MS plasma (LA-MC-ICP-MS|OES). Both methods are evaluated using international geological reference materials. Accurate and precise Si isotope ratios were obtained with an uncertainty typically better than 0.23‰, 2SD, δ{sup 30}Si. With both methods major element concentrations (e.g., Na, Al, Si, Mg, Ca) can be simultaneously determined. However, LASS-ICP-MS is superior over LA-MC-ICP-MS|OES, which is limited by its lower sensitivity. Moreover, LASS-ICP-MS offers trace element analysis down to the μg g{sup −1}-range for more than 28 elements due to lower limits of detection, and with typical uncertainties better than 15%. For in situ

Development of routines for simultaneous in situ chemical composition and stable Si isotope ratio analysis by femtosecond laser ablation inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Frick, Daniel A.; Schuessler, Jan A.; Blanckenburg, Friedhelm von

2016-01-01

Stable metal (e.g. Li, Mg, Ca, Fe, Cu, Zn, and Mo) and metalloid (B, Si, Ge) isotope ratio systems have emerged as geochemical tracers to fingerprint distinct physicochemical reactions. These systems are relevant to many Earth Science questions. The benefit of in situ microscale analysis using laser ablation (LA) over bulk sample analysis is to use the spatial context of different phases in the solid sample to disclose the processes that govern their chemical and isotopic compositions. However, there is a lack of in situ analytical routines to obtain a samples' stable isotope ratio together with its chemical composition. Here, we evaluate two novel analytical routines for the simultaneous determination of the chemical and Si stable isotope composition (δ 30 Si) on the micrometre scale in geological samples. In both routines, multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is combined with femtosecond-LA, where stable isotope ratios are corrected for mass bias using standard-sample-bracketing with matrix-independent calibration. The first method is based on laser ablation split stream (LASS), where the laser aerosol is split and introduced simultaneously into both the MC-ICP-MS and a quadrupole ICP-MS. The second method is based on optical emission spectroscopy using direct observation of the MC-ICP-MS plasma (LA-MC-ICP-MS|OES). Both methods are evaluated using international geological reference materials. Accurate and precise Si isotope ratios were obtained with an uncertainty typically better than 0.23‰, 2SD, δ 30 Si. With both methods major element concentrations (e.g., Na, Al, Si, Mg, Ca) can be simultaneously determined. However, LASS-ICP-MS is superior over LA-MC-ICP-MS|OES, which is limited by its lower sensitivity. Moreover, LASS-ICP-MS offers trace element analysis down to the μg g −1 -range for more than 28 elements due to lower limits of detection, and with typical uncertainties better than 15%. For in situ

Wideband quin-stable energy harvesting via combined nonlinearity

Directory of Open Access Journals (Sweden)

Chen Wang

2017-04-01

Full Text Available In this work, we propose a wideband quintuple-well potential piezoelectric-based vibration energy harvester using a combined nonlinearity: the magnetic nonlinearity induced by magnetic force and the piecewise-linearity produced by mechanical impact. With extra stable states compared to other multi-stable harvesters, the quin-stable harvester can distribute its potential energy more uniformly, which provides shallower potential wells and results in lower excitation threshold for interwell motion. The mathematical model of this quin-stable harvester is derived and its equivalent piecewise-nonlinear restoring force is measured in the experiment and identified as piecewise polynomials. Numerical simulations and experimental verifications are performed in different levels of sinusoid excitation ranging from 1 to 25 Hz. The results demonstrate that, with lower potential barriers compared with tri-stable counterpart, the quin-stable arrangement can escape potential wells more easily for doing high-energy interwell motion over a wider band of frequencies. Moreover, by utilizing the mechanical stoppers, this harvester can produce significant output voltage under small tip deflections, which results in a high power density and is especially suitable for a compact MEMS approach.

Optimization of post-run corrections for water stable isotope measurements by laser spectroscopy

Science.gov (United States)

van Geldern, Robert; Barth, Johannes A. C.

2013-04-01

Light stable isotope analyses of hydrogen and oxygen of water are used in numerous aquatic studies from various scientific fields. The advantage of using stable isotope ratios is that water molecules serve as ubiquitous and already present natural tracers. Traditionally, the samples were analyzed in the laboratory by isotope ratio mass spectrometry (IRMS). Within recent years these analyses have been revolutionized by the development of new isotope ratio laser spectroscopy (IRIS) systems that are said to be cheaper, more robust and mobile compared to IRMS. Although easier to operate, laser systems also need thorough calibration with international reference materials and raw data need correction for analytical effects. A major issue in systems that use liquid injection via a vaporizer module is the memory effect, i.e. the carry-over from the previous analyzed sample in a sequence. This study presents an optimized and simple post-run correction procedure for liquid water injection developed for a Picarro water analyzer. The Excel(TM) template will rely exclusively on standard features implemented in MS Office without the need to run macros, additional code written in Visual Basic for Applications (VBA) or to use a database-related software such as MS Access or SQL Server. These protocols will maximize precision, accuracy and sample throughput via an efficient memory correction. The number of injections per unknown sample can be reduced to 4 or less. This procedure meets the demands of faster throughput with reduced costs per analysis. Procedures were verified by an international proficiency test and traditional IRMS techniques. The template is available free for scientific use from the corresponding author or the journals web site (van Geldern and Barth, 2012). References van Geldern, R. and Barth, J.A.C. (2012) Limnol. Oceanogr. Methods 10:1024-1036 [doi: 10.4319/lom.2012.10.1024

Stable carbides in transition metal alloys

International Nuclear Information System (INIS)

Piotrkowski, R.

1991-01-01

In the present work different techniques were employed for the identification of stable carbides in two sets of transition metal alloys of wide technological application: a set of three high alloy M2 type steels in which W and/or Mo were total or partially replaced by Nb, and a Zr-2.5 Nb alloy. The M2 steel is a high speed steel worldwide used and the Zr-2.5 Nb alloy is the base material for the pressure tubes in the CANDU type nuclear reactors. The stability of carbide was studied in the frame of Goldschmidt's theory of interstitial alloys. The identification of stable carbides in steels was performed by determining their metallic composition with an energy analyzer attached to the scanning electron microscope (SEM). By these means typical carbides of the M2 steel, MC and M 6 C, were found. Moreover, the spatial and size distribution of carbide particles were determined after different heat treatments, and both microstructure and microhardness were correlated with the appearance of the secondary hardening phenomenon. In the Zr-Nb alloy a study of the α and β phases present after different heat treatments was performed with optical and SEM metallographic techniques, with the guide of Abriata and Bolcich phase diagram. The α-β interphase boundaries were characterized as short circuits for diffusion with radiotracer techniques and applying Fisher-Bondy-Martin model. The precipitation of carbides was promoted by heat treatments that produced first the C diffusion into the samples at high temperatures (β phase), and then the precipitation of carbide particles at lower temperature (α phase or (α+β)) two phase field. The precipitated carbides were identified as (Zr, Nb)C 1-x with SEM, electron microprobe and X-ray diffraction techniques. (Author) [es

Stable isotopes as tracers for radionuclides

International Nuclear Information System (INIS)

Giussani, A.; Bartolo, D. de; Cantone, M.C.; Zilker, T.; Greim, H.; Roth, P.; Werner, E.

2000-01-01

The assessment of internal dose after incorporation of radionuclides requires as input data the knowledge of the uptake into the systemic circulation, the distribution and retention in selected organs, the excretion pathways. Realistic biokinetic models are needed for reliable estimates, correct interpretation of bioassay measurements, appropriate decision-making in radiological emergencies. For many radionuclides, however, the biokinetic models currently recommended are often generic, with very few specific parameters, due to the lack of experimental human data. The use of stable isotopes as tracers enables to determine important biokinetic parameters such as the fractional uptake, the clearance from the transfer compartment, the excretion patterns under experimentally controlled conditions. The subjects investigated are not exposed to any radiation risk, so this technique enables to obtain biokinetic information also for sensitive groups of the population, such as children or pregnant women, and to determine age- and gender-specific model parameters. Sophisticated analytical method, able to discriminate and quantitate different isotopes of the same element in complex matrices such as biological fluids, have to be purposely developed and optimized. Activation analysis and mass spectrometry are the most proper techniques of choice. Experiments were conducted with molybdenum, tellurium, ruthenium and zirconium. Activation analysis with protons, thermal ionization mass spectrometry and inductively coupled mass spectrometry were employed for the determination of stable isotopes of these elements in blood plasma and urine samples. Several deviations from the predictions of the ICRP models were observed. For example, modifications to the current model for molybdenum have been suggested on the basis of these results. The dose coefficients to the target regions calculated with this proposed model are even of one order of magnitude different than the ICRP estimates

Multi-frequency direct sampling method in inverse scattering problem

Science.gov (United States)

Kang, Sangwoo; Lambert, Marc; Park, Won-Kwang

2017-10-01

We consider the direct sampling method (DSM) for the two-dimensional inverse scattering problem. Although DSM is fast, stable, and effective, some phenomena remain unexplained by the existing results. We show that the imaging function of the direct sampling method can be expressed by a Bessel function of order zero. We also clarify the previously unexplained imaging phenomena and suggest multi-frequency DSM to overcome traditional DSM. Our method is evaluated in simulation studies using both single and multiple frequencies.

Lead isotope ratio analysis of bullet samples by using quadrupole ICP-MS

International Nuclear Information System (INIS)

Tamura, Shu-ichi; Hokura, Akiko; Nakai, Izumi; Oishi, Masahiro

2006-01-01

The measurement conditions for the precise analysis of the lead stable isotope ratio by using an ICP-MS equipped with a quadrupole mass spectrometer were studied in order to apply the technique to the forensic identification of bullet samples. The values of the relative standard deviation obtained for the ratio of 208 Pb/ 206 Pb, 207 Pb/ 206 Pb and 204 Pb/ 206 Pb were lower than 0.2% after optimization of the analytical conditions, including the optimum lead concentration of the sample solution to be about 70 ppb and an integration time for 1 m/s of 15 s. This method was applied to an analysis of lead in bullets for rifles and handguns; a stable isotope ratio of lead was found to be suitable for the identification of bullets. This study has demonstrated that the lead isotope ratio measured by using a quadrupole ICP-MS was useful for a practical analysis of bullet samples in forensic science. (author)

Sense of Humor, Stable Affect, and Psychological Well-Being

Directory of Open Access Journals (Sweden)

Arnie Cann

2014-08-01

Full Text Available A good sense of humor has been implicated as a quality that could contribute to psychological well-being. The mechanisms through which sense of humor might operate include helping to reappraise threats, serving as a character strength, or facilitating happiness. The current research attempts to integrate these possibilities by examining whether a good sense of humor might operate globally by helping to maintain a more stable positive affect. Stable positive affect has been shown to facilitate more effective problem solving and to build resilience. However, not all humor is adaptive humor, so we also examine the roles that different styles of humor use might play. Individual differences in humor styles were used to predict stable levels of affect. Then, in a longitudinal design, humor styles and stable affect were used to predict subsequent resilience and psychological health. The results indicated that stable affect was related to resilience and psychological well-being, and that a sense of humor that involves self-enhancing humor, humor based on maintaining a humorous perspective about one’s experiences, was positively related to stable positive affect, negatively related to stable negative affect, and was mediated through stable affect in influencing resilience, well-being and distress. Thus, while a good sense of humor can lead to greater resilience and better psychological health, the current results, focusing on stable affect, find only self-enhancing humor provides reliable benefits.

[Variations and simulation of stable isotopes in precipitation in the Heihe River basin].

Science.gov (United States)

Wu, Jin-Kui; Yang, Qi-Yue; Ding, Yong-Jian; Ye, Bai-Sheng; Zhang, Ming-Quan

2011-07-01

To study the variations of deltaD and delta18O in precipitation, 301 samples were sampled during 2002-2004 in 6 sites in the Heihe River basin, Northwestern China. The deltaD and delta18O values ranged from 59 per thousand to -254 per thousand and 6.5 per thousand to -33.4 per thousand, respectively. This wide range indicated that stable isotopes in precipitation were controlled by different condensation mechanisms as a function of air temperature and varying sources of moisture. delta18O in precipitation had a close positive relationship with the air temperature, i. e., a clear temperature effect existed in this area. At a monthly scale, no precipitation effect existed. On the other hand, a weak precipitation effect still accrued at precipitation events scale. The spatial variation of delta18O showed that the weighted average delta18O values decreased with the increasing altitude of sampling sites at a gradient of -0. 47 per thousand/100m. A regional Meteoric Water Line, deltaD = 7.82 delta18O + 7.63, was nearly identical to the Meteoric Water Line in the Northern China. The results of backward trajectory of each precipitation day at Xishui showed that the moisture of the precipitation in cold season (October to March) mainly originated from the west while the moisture source was more complicated in warm season (April to September). The simulation of seasonal delta18O variation showed that the stable isotope composition of precipitation tended to a clear sine-wave seasonal variation.

C–O Stable Isotopes Geochemistry of Tunisian Nonsulfide Zinc Deposits: A First Look

Directory of Open Access Journals (Sweden)

Hechmi Garnit

2018-01-01

Full Text Available A preliminary C–O stable isotopes geochemical characterization of several nonsulfide Zn-Pb Tunisian deposits has been carried out, in order to evidence the possible differences in their genesis. Nonsulfide ores were sampled from the following deposits: Ain Allegua, Jebel Ben Amara, Jebel Hallouf (Nappe Zone, Djebba, Bou Grine, Bou Jaber, Fedj el Adoum, Slata Fer (Diapir Zone, Jebel Ressas, Jebel Azreg, Mecella (North South Axis Zone, Jebel Trozza, Sekarna (Graben Zone. After mineralogical investigation of selected specimens, the C–O stable isotopic study was carried out on smithsonite, hydrozincite, cerussite and calcite. The data have shown that all the carbonate generations in the oxidized zones of Ain Allegua and Jebel Ben Amara (Nappe Zone, Bou Jaber, Bou Grine and Fedj el Adoum (Diapir Zone, Mecella and Jebel Azreg (North South Zone have a supergene origin, whereas the carbonates sampled at Sekarna (Graben Zone (and in limited part also at Bou Jaber precipitated from thermal waters at moderately high temperature. Most weathering processes that controlled the supergene alteration of the Zn-Pb sulfide deposits in Tunisia had probably started in the middle to late Miocene interval and at the beginning of the Pliocene, both periods corresponding to two distinct tectonic pulses that produced the exhumation of sulfide ores, but the alteration and formation of oxidized minerals could have also continued through the Quaternary. The isotopic characteristics associated with the weathering processes in the sampled localities were controlled by the different locations of the sulfide protores within the tectonic and climatic zones of Tunisia during the late Tertiary and Quaternary.

Applications of stable isotopes in clinical pharmacology

NARCIS (Netherlands)

Schellekens, Reinout C A; Stellaard, Frans; Woerdenbag, Herman J; Frijlink, Henderik W; Kosterink, Jos G W

2011-01-01

This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the

Search for Heavy Stable Charged Particles in pp collisions at $\\sqrt{s}$ = 7 TeV

CERN Document Server

Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Haensel, Stephan; Hartl, Christian; Hoch, Michael; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kasieczka, Gregor; Kiesenhofer, Wolfgang; Krammer, Manfred; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Teischinger, Florian; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Benucci, Leonardo; Ceard, Ludivine; Cerny, Karel; De Wolf, Eddi A.; Janssen, Xavier; Maes, Thomas; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Adler, Volker; Beauceron, Stephanie; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Devroede, Olivier; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Joris; Maes, Michael; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Charaf, Otman; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hammad, Gregory Habib; Hreus, Tomas; Marage, Pierre Edouard; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wickens, John; Costantini, Silvia; Grunewald, Martin; Klein, Benjamin; Marinov, Andrey; Mccartin, Joseph; Ryckbosch, Dirk; Thyssen, Filip; Tytgat, Michael; Vanelderen, Lukas; Verwilligen, Piet; Walsh, Sinead; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Caudron, Julien; De Favereau De Jeneret, Jerome; Delaere, Christophe; Demin, Pavel; Favart, Denis; Giammanco, Andrea; Grégoire, Ghislain; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Ovyn, Severine; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Quertenmont, Loic; Schul, Nicolas; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Alves, Gilvan; De Jesus Damiao, Dilson; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Carvalho, Wagner; Melo Da Costa, Eliza; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Silva Do Amaral, Sheila Mara; Sznajder, Andre; De Almeida Dias, Flavia; Ferreira Dias, Marco Andre; Tomei, Thiago; De Moraes Gregores, Eduardo; Da Cunha Marinho, Franciole; Novaes, Sergio F.; Padula, Sandra; Darmenov, Nikolay; Dimitrov, Lubomir; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vankov, Ivan; Dyulendarova, Milena; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Marinova, Evelina; Mateev, Matey; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Wang, Jian; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xu, Ming; Yang, Min; Zang, Jingjing; Zhang, Zhen; Ban, Yong; Guo, Shuang; Li, Wenbo; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Zhang, Linlin; Zhu, Bo; Cabrera, Andrés; Gomez Moreno, Bernardo; Ocampo Rios, Alberto Andres; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Lelas, Karlo; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Dzelalija, Mile; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A.; Rykaczewski, Hans; Assran, Yasser; Mahmoud, Mohammed; Hektor, Andi; Kadastik, Mario; Kannike, Kristjan; Müntel, Mait; Raidal, Martti; Rebane, Liis; Azzolini, Virginia; Eerola, Paula; Czellar, Sandor; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Klem, Jukka; Kortelainen, Matti J.; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Korpela, Arja; Tuuva, Tuure; Sillou, Daniel; Besancon, Marc; Choudhury, Somnath; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Ferri, Federico; Ganjour, Serguei; Gentit, François-Xavier; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Marionneau, Matthieu; Millischer, Laurent; Rander, John; Rosowsky, André; Shreyber, Irina; Titov, Maksym; Verrecchia, Patrice; Baffioni, Stephanie; Beaudette, Florian; Bianchini, Lorenzo; Bluj, Michal; Broutin, Clementine; Busson, Philippe; Charlot, Claude; Dahms, Torsten; Dobrzynski, Ludwik; Granier de Cassagnac, Raphael; Haguenauer, Maurice; Miné, Philippe; Mironov, Camelia; Ochando, Christophe; Paganini, Pascal; Sabes, David; Salerno, Roberto; Sirois, Yves; Thiebaux, Christophe; Wyslouch, Bolek; Zabi, Alexandre; Agram, Jean-Laurent; Andrea, Jeremy; Besson, Auguste; Bloch, Daniel; Bodin, David; Brom, Jean-Marie; Cardaci, Marco; Chabert, Eric Christian; Collard, Caroline; Conte, Eric; Drouhin, Frédéric; Ferro, Cristina; Fontaine, Jean-Charles; Gelé, Denis; Goerlach, Ulrich; Greder, Sebastien; Juillot, Pierre; Karim, Mehdi; Le Bihan, Anne-Catherine; Mikami, Yoshinari; Van Hove, Pierre; Fassi, Farida; Mercier, Damien; Baty, Clement; Beaupere, Nicolas; Bedjidian, Marc; Bondu, Olivier; Boudoul, Gaelle; Boumediene, Djamel; Brun, Hugues; Chanon, Nicolas; Chierici, Roberto; Contardo, Didier; Depasse, Pierre; El Mamouni, Houmani; Falkiewicz, Anna; Fay, Jean; Gascon, Susan; Ille, Bernard; Kurca, Tibor; Le Grand, Thomas; Lethuillier, Morgan; Mirabito, Laurent; Perries, Stephane; Sordini, Viola; Tosi, Silvano; Tschudi, Yohann; Verdier, Patrice; Xiao, Hong; Roinishvili, Vladimir; Anagnostou, Georgios; Edelhoff, Matthias; Feld, Lutz; Heracleous, Natalie; Hindrichs, Otto; Jussen, Ruediger; Klein, Katja; Merz, Jennifer; Mohr, Niklas; Ostapchuk, Andrey; Perieanu, Adrian; Raupach, Frank; Sammet, Jan; Schael, Stefan; Sprenger, Daniel; Weber, Hendrik; Weber, Martin; Wittmer, Bruno; Ata, Metin; Bender, Walter; Erdmann, Martin; Frangenheim, Jens; Hebbeker, Thomas; Hinzmann, Andreas; Hoepfner, Kerstin; Hof, Carsten; Klimkovich, Tatsiana; Klingebiel, Dennis; Kreuzer, Peter; Lanske, Dankfried; Magass, Carsten; Masetti, Gianni; Merschmeyer, Markus; Meyer, Arnd; Papacz, Paul; Pieta, Holger; Reithler, Hans; Schmitz, Stefan Antonius; Sonnenschein, Lars; Steggemann, Jan; Teyssier, Daniel; Bontenackels, Michael; Davids, Martina; Duda, Markus; Flügge, Günter; Geenen, Heiko; Giffels, Manuel; Haj Ahmad, Wael; Heydhausen, Dirk; Kress, Thomas; Kuessel, Yvonne; Linn, Alexander; Nowack, Andreas; Perchalla, Lars; Pooth, Oliver; Rennefeld, Jörg; Sauerland, Philip; Stahl, Achim; Thomas, Maarten; Tornier, Daiske; Zoeller, Marc Henning; Aldaya Martin, Maria; Behrenhoff, Wolf; Behrens, Ulf; Bergholz, Matthias; Borras, Kerstin; Cakir, Altan; Campbell, Alan; Castro, Elena; Dammann, Dirk; Eckerlin, Guenter; Eckstein, Doris; Flossdorf, Alexander; Flucke, Gero; Geiser, Achim; Glushkov, Ivan; Hauk, Johannes; Jung, Hannes; Kasemann, Matthias; Katkov, Igor; Katsas, Panagiotis; Kleinwort, Claus; Kluge, Hannelies; Knutsson, Albert; Krücker, Dirk; Kuznetsova, Ekaterina; Lange, Wolfgang; Lohmann, Wolfgang; Mankel, Rainer; Marienfeld, Markus; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mnich, Joachim; Mussgiller, Andreas; Olzem, Jan; Parenti, Andrea; Raspereza, Alexei; Raval, Amita; Schmidt, Ringo; Schoerner-Sadenius, Thomas; Sen, Niladri; Stein, Matthias; Tomaszewska, Justyna; Volyanskyy, Dmytro; Walsh, Roberval; Wissing, Christoph; Autermann, Christian; Bobrovskyi, Sergei; Draeger, Jula; Enderle, Holger; Gebbert, Ulla; Kaschube, Kolja; Kaussen, Gordon; Klanner, Robert; Lange, Jörn; Mura, Benedikt; Naumann-Emme, Sebastian; Nowak, Friederike; Pietsch, Niklas; Sander, Christian; Schettler, Hannes; Schleper, Peter; Schröder, Matthias; Schum, Torben; Schwandt, Joern; Srivastava, Ajay Kumar; Stadie, Hartmut; Steinbrück, Georg; Thomsen, Jan; Wolf, Roger; Barth, Christian; Bauer, Julia; Buege, Volker; Chwalek, Thorsten; De Boer, Wim; Dierlamm, Alexander; Dirkes, Guido; Feindt, Michael; Gruschke, Jasmin; Hackstein, Christoph; Hartmann, Frank; Heindl, Stefan Michael; Heinrich, Michael; Held, Hauke; Hoffmann, Karl-Heinz; Honc, Simon; Kuhr, Thomas; Martschei, Daniel; Mueller, Steffen; Müller, Thomas; Niegel, Martin; Oberst, Oliver; Oehler, Andreas; Ott, Jochen; Peiffer, Thomas; Piparo, Danilo; Quast, Gunter; Rabbertz, Klaus; Ratnikov, Fedor; Renz, Manuel; Saout, Christophe; Scheurer, Armin; Schieferdecker, Philipp; Schilling, Frank-Peter; Schott, Gregory; Simonis, Hans-Jürgen; Stober, Fred-Markus Helmut; Troendle, Daniel; Wagner-Kuhr, Jeannine; Zeise, Manuel; Zhukov, Valery; Ziebarth, Eva Barbara; Daskalakis, Georgios; Geralis, Theodoros; Kesisoglou, Stilianos; Kyriakis, Aristotelis; Loukas, Demetrios; Manolakos, Ioannis; Markou, Athanasios; Markou, Christos; Mavrommatis, Charalampos; Petrakou, Eleni; Gouskos, Loukas; Mertzimekis, Theodoros; Panagiotou, Apostolos; Evangelou, Ioannis; Foudas, Costas; Kokkas, Panagiotis; Manthos, Nikolaos; Papadopoulos, Ioannis; Patras, Vaios; Triantis, Frixos A.; Aranyi, Attila; Bencze, Gyorgy; Boldizsar, Laszlo; Debreczeni, Gergely; Hajdu, Csaba; Horvath, Dezso; Kapusi, Anita; Krajczar, Krisztian; Laszlo, Andras; Sikler, Ferenc; Vesztergombi, Gyorgy; Beni, Noemi; Molnar, Jozsef; Palinkas, Jozsef; Szillasi, Zoltan; Veszpremi, Viktor; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; Bansal, Sunil; Beri, Suman Bala; Bhatnagar, Vipin; Dhingra, Nitish; Jindal, Monika; Kaur, Manjit; Kohli, Jatinder Mohan; Mehta, Manuk Zubin; Nishu, Nishu; Saini, Lovedeep Kaur; Sharma, Archana; Singh, Anil; Singh, Jas Bir; Singh, Supreet Pal; Ahuja, Sudha; Bhattacharya, Satyaki; Choudhary, Brajesh C.; Gupta, Pooja; Jain, Sandhya; Jain, Shilpi; Kumar, Ashok; Shivpuri, Ram Krishen; Choudhury, Rajani Kant; Dutta, Dipanwita; Kailas, Swaminathan; Kataria, Sushil Kumar; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Aziz, Tariq; Guchait, Monoranjan; Gurtu, Atul; Maity, Manas; Majumder, Devdatta; Majumder, Gobinda; Mazumdar, Kajari; Mohanty, Gagan Bihari; Saha, Anirban; Sudhakar, Katta; Wickramage, Nadeesha; Banerjee, Sudeshna; Dugad, Shashikant; Mondal, Naba Kumar; Arfaei, Hessamaddin; Bakhshiansohi, Hamed; Etesami, Seyed Mohsen; Fahim, Ali; Hashemi, Majid; Jafari, Abideh; Khakzad, Mohsen; Mohammadi, Abdollah; Mohammadi Najafabadi, Mojtaba; Paktinat Mehdiabadi, Saeid; Safarzadeh, Batool; Zeinali, Maryam; Abbrescia, Marcello; Barbone, Lucia; Calabria, Cesare; Colaleo, Anna; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Dimitrov, Anton; Fiore, Luigi; Iaselli, Giuseppe; Lusito, Letizia; Maggi, Giorgio; Maggi, Marcello; Manna, Norman; Marangelli, Bartolomeo; My, Salvatore; Nuzzo, Salvatore; Pacifico, Nicola; Pierro, Giuseppe Antonio; Pompili, Alexis; Pugliese, Gabriella; Romano, Francesco; Roselli, Giuseppe; Selvaggi, Giovanna; Silvestris, Lucia; Trentadue, Raffaello; Tupputi, Salvatore; Zito, Giuseppe; Abbiendi, Giovanni; Benvenuti, Alberto; Bonacorsi, Daniele; Braibant-Giacomelli, Sylvie; Brigliadori, Luca; Capiluppi, Paolo; Castro, Andrea; Cavallo, Francesca Romana; Cuffiani, Marco; Dallavalle, Gaetano-Marco; Fabbri, Fabrizio; Fanfani, Alessandra; Fasanella, Daniele; Giacomelli, Paolo; Giunta, Marina; Marcellini, Stefano; Meneghelli, Marco; Montanari, Alessandro; Navarria, Francesco; Odorici, Fabrizio; Perrotta, Andrea; Primavera, Federica; Rossi, Antonio; Rovelli, Tiziano; Siroli, Gianni; Travaglini, Riccardo; Albergo, Sebastiano; Cappello, Gigi; Chiorboli, Massimiliano; Costa, Salvatore; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Gallo, Elisabetta; Genta, Chiara; Lenzi, Piergiulio; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Tropiano, Antonio; Benussi, Luigi; Bianco, Stefano; Colafranceschi, Stefano; Fabbri, Franco; Piccolo, Davide; Fabbricatore, Pasquale; Musenich, Riccardo; Benaglia, Andrea; De Guio, Federico; Di Matteo, Leonardo; Ghezzi, Alessio; Malberti, Martina; Malvezzi, Sandra; Martelli, Arabella; Massironi, Andrea; Menasce, Dario; Moroni, Luigi; Paganoni, Marco; Pedrini, Daniele; Ragazzi, Stefano; Redaelli, Nicola; Sala, Silvano; Tabarelli de Fatis, Tommaso; Tancini, Valentina; Buontempo, Salvatore; Carrillo Montoya, Camilo Andres; Cimmino, Anna; De Cosa, Annapaola; De Gruttola, Michele; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lista, Luca; Merola, Mario; Noli, Pasquale; Paolucci, Pierluigi; Azzi, Patrizia; Bacchetta, Nicola; Bellan, Paolo; Bisello, Dario; Branca, Antonio; Carlin, Roberto; Conti, Enrico; De Mattia, Marco; Dorigo, Tommaso; Fanzago, Federica; Gasparini, Fabrizio; Giubilato, Piero; Gonella, Franco; Gresele, Ambra; Lacaprara, Stefano; Lazzizzera, Ignazio; Margoni, Martino; Mazzucato, Mirco; Meneguzzo, Anna Teresa; Nespolo, Massimo; Pegoraro, Matteo; Perrozzi, Luca; Pozzobon, Nicola; Ronchese, Paolo; Torassa, Ezio; Tosi, Mia; Triossi, Andrea; Vanini, Sara; Ventura, Sandro; Zumerle, Gianni; Baesso, Paolo; Berzano, Umberto; Riccardi, Cristina; Torre, Paola; Vitulo, Paolo; Viviani, Claudio; Biasini, Maurizio; Bilei, Gian Mario; Caponeri, Benedetta; Fanò, Livio; Lariccia, Paolo; Lucaroni, Andrea; Mantovani, Giancarlo; Menichelli, Mauro; Nappi, Aniello; Santocchia, Attilio; Servoli, Leonello; Taroni, Silvia; Valdata, Marisa; Volpe, Roberta; Azzurri, Paolo; Bagliesi, Giuseppe; Bernardini, Jacopo; Boccali, Tommaso; Broccolo, Giuseppe; Castaldi, Rino; D'Agnolo, Raffaele Tito; Dell'Orso, Roberto; Fiori, Francesco; Foà, Lorenzo; Giassi, Alessandro; Kraan, Aafke; Ligabue, Franco; Lomtadze, Teimuraz; Martini, Luca; Messineo, Alberto; Palla, Fabrizio; Palmonari, Francesco; Sarkar, Subir; Segneri, Gabriele; Serban, Alin Titus; Spagnolo, Paolo; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Barone, Luciano; Cavallari, Francesca; Del Re, Daniele; Di Marco, Emanuele; Diemoz, Marcella; Franci, Daniele; Grassi, Marco; Longo, Egidio; Organtini, Giovanni; Palma, Alessandro; Pandolfi, Francesco; Paramatti, Riccardo; Rahatlou, Shahram; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Biino, Cristina; Botta, Cristina; Cartiglia, Nicolo; Castello, Roberto; Costa, Marco; Demaria, Natale; Graziano, Alberto; Mariotti, Chiara; Marone, Matteo; Maselli, Silvia; Migliore, Ernesto; Mila, Giorgia; Monaco, Vincenzo; Musich, Marco; Obertino, Maria Margherita; Pastrone, Nadia; Pelliccioni, Mario; Romero, Alessandra; Ruspa, Marta; Sacchi, Roberto; Sola, Valentina; Solano, Ada; Staiano, Amedeo; Trocino, Daniele; Vilela Pereira, Antonio; Ambroglini, Filippo; Belforte, Stefano; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; Montanino, Damiana; Penzo, Aldo; Heo, Seong Gu; Chang, Sunghyun; Chung, Jin Hyuk; Kim, Dong Hee; Kim, Gui Nyun; Kim, Ji Eun; Kong, Dae Jung; Park, Hyangkyu; Son, Dohhee; Son, Dong-Chul; Kim, Jaeho; Kim, Jae Yool; Song, Sanghyeon; Choi, Suyong; Hong, Byung-Sik; Jo, Mihee; Kim, Hyunchul; Kim, Ji Hyun; Kim, Tae Jeong; Lee, Kyong Sei; Moon, Dong Ho; Park, Sung Keun; Rhee, Han-Bum; Seo, Eunsung; Shin, Seungsu; Sim, Kwang Souk; Choi, Minkyoo; Kang, Seokon; Kim, Hyunyong; Park, Chawon; Park, Inkyu; Park, Sangnam; Ryu, Geonmo; Choi, Young-Il; Choi, Young Kyu; Goh, Junghwan; Lee, Jongseok; Lee, Sungeun; Seo, Hyunkwan; Yu, Intae; Bilinskas, Mykolas Jurgis; Grigelionis, Ignas; Janulis, Mindaugas; Martisiute, Dalia; Petrov, Pavel; Sabonis, Tomas; Castilla Valdez, Heriberto; De La Cruz Burelo, Eduard; Lopez-Fernandez, Ricardo; Sánchez Hernández, Alberto; Villasenor-Cendejas, Luis Manuel; Carrillo Moreno, Salvador; Vazquez Valencia, Fabiola; Salazar Ibarguen, Humberto Antonio; Casimiro Linares, Edgar; Morelos Pineda, Antonio; Reyes-Santos, Marco A.; Allfrey, Philip; Krofcheck, David; Butler, Philip H.; Doesburg, Robert; Silverwood, Hamish; Ahmad, Muhammad; Ahmed, Ijaz; Asghar, Muhammad Irfan; Hoorani, Hafeez R.; Khan, Wajid Ali; Khurshid, Taimoor; Qazi, Shamona; Cwiok, Mikolaj; Dominik, Wojciech; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Frueboes, Tomasz; Gokieli, Ryszard; Górski, Maciej; Kazana, Malgorzata; Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Wrochna, Grzegorz; Zalewski, Piotr; Almeida, Nuno; David Tinoco Mendes, Andre; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Sá Martins, Pedro; Musella, Pasquale; Nayak, Aruna; Ribeiro, Pedro Quinaz; Seixas, Joao; Silva, Pedro; Varela, Joao; Wöhri, Hermine Katharina; Belotelov, Ivan; Bunin, Pavel; Finger, Miroslav; Finger Jr., Michael; Golutvin, Igor; Kamenev, Alexey; Karjavin, Vladimir; Kozlov, Guennady; Lanev, Alexander; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Shmatov, Sergey; Smirnov, Vitaly; Volodko, Anton; Zarubin, Anatoli; Bondar, Nikolai; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Levchenko, Petr; Murzin, Victor; Oreshkin, Vadim; Smirnov, Igor; Sulimov, Valentin; Uvarov, Lev; Vavilov, Sergey; Vorobyev, Alexey; Andreev, Yuri; Gninenko, Sergei; Golubev, Nikolai; Kirsanov, Mikhail; Krasnikov, Nikolai; Matveev, Viktor; Pashenkov, Anatoli; Toropin, Alexander; Troitsky, Sergey; Epshteyn, Vladimir; Gavrilov, Vladimir; Kaftanov, Vitali; Kossov, Mikhail; Krokhotin, Andrey; Lychkovskaya, Natalia; Safronov, Grigory; Semenov, Sergey; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Boos, Edouard; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Kodolova, Olga; Lokhtin, Igor; Obraztsov, Stepan; Petrushanko, Sergey; Sarycheva, Ludmila; Savrin, Viktor; Snigirev, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Rusakov, Sergey V.; Vinogradov, Alexey; Azhgirey, Igor; Bitioukov, Sergei; Grishin, Viatcheslav; Kachanov, Vassili; Konstantinov, Dmitri; Korablev, Andrey; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Slabospitsky, Sergey; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Djordjevic, Milos; Krpic, Dragomir; Milosevic, Jovan; Aguilar-Benitez, Manuel; Alcaraz Maestre, Juan; Arce, Pedro; Battilana, Carlo; Calvo, Enrique; Cepeda, Maria; Cerrada, Marcos; Colino, Nicanor; De La Cruz, Begona; Diez Pardos, Carmen; Domínguez Vázquez, Daniel; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Ferrando, Antonio; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M.; Josa, Maria Isabel; Merino, Gonzalo; Puerta Pelayo, Jesus; Redondo, Ignacio; Romero, Luciano; Santaolalla, Javier; Willmott, Carlos; Albajar, Carmen; Codispoti, Giuseppe; de Trocóniz, Jorge F; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Lloret Iglesias, Lara; Vizan Garcia, Jesus Manuel; Brochero Cifuentes, Javier Andres; Cabrillo, Iban Jose; Calderon, Alicia; Chamizo Llatas, Maria; Chuang, Shan-Huei; Duarte Campderros, Jordi; Felcini, Marta; Fernandez, Marcos; Gomez, Gervasio; Gonzalez Sanchez, Javier; Jorda, Clara; Lobelle Pardo, Patricia; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Munoz Sanchez, Francisca Javiela; Piedra Gomez, Jonatan; Rodrigo, Teresa; Ruiz Jimeno, Alberto; Scodellaro, Luca; Sobron Sanudo, Mar; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Baillon, Paul; Ball, Austin; Barney, David; Bell, Alan James; Benedetti, Daniele; Bernet, Colin; Bialas, Wojciech; Bloch, Philippe; Bocci, Andrea; Bolognesi, Sara; Breuker, Horst; Brona, Grzegorz; Bunkowski, Karol; Camporesi, Tiziano; Cano, Eric; Cerminara, Gianluca; Christiansen, Tim; Coarasa Perez, Jose Antonio; Curé, Benoît; D'Enterria, David; De Roeck, Albert; Duarte Ramos, Fernando; Elliott-Peisert, Anna; Frisch, Benjamin; Funk, Wolfgang; Gaddi, Andrea; Gennai, Simone; Georgiou, Georgios; Gerwig, Hubert; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Glege, Frank; Gomez-Reino Garrido, Robert; Gouzevitch, Maxime; Govoni, Pietro; Gowdy, Stephen; Guiducci, Luigi; Hansen, Magnus; Harvey, John; Hegeman, Jeroen; Hegner, Benedikt; Henderson, Conor; Hesketh, Gavin; Hoffmann, Hans Falk; Honma, Alan; Innocente, Vincenzo; Janot, Patrick; Karavakis, Edward; Lecoq, Paul; Leonidopoulos, Christos; Lourenco, Carlos; Macpherson, Alick; Maki, Tuula; Malgeri, Luca; Mannelli, Marcello; Masetti, Lorenzo; Meijers, Frans; Mersi, Stefano; Meschi, Emilio; Moser, Roland; Mozer, Matthias Ulrich; Mulders, Martijn; Nesvold, Erik; Nguyen, Matthew; Orimoto, Toyoko; Orsini, Luciano; Perez, Emmanuelle; Petrilli, Achille; Pfeiffer, Andreas; Pierini, Maurizio; Pimiä, Martti; Polese, Giovanni; Racz, Attila; Rolandi, Gigi; Rommerskirchen, Tanja; Rovelli, Chiara; Rovere, Marco; Sakulin, Hannes; Schäfer, Christoph; Schwick, Christoph; Segoni, Ilaria; Sharma, Archana; Siegrist, Patrice; Simon, Michal; Sphicas, Paraskevas; Spiga, Daniele; Spiropulu, Maria; Stöckli, Fabian; Stoye, Markus; Tropea, Paola; Tsirou, Andromachi; Tsyganov, Andrey; Veres, Gabor Istvan; Vichoudis, Paschalis; Voutilainen, Mikko; Zeuner, Wolfram Dietrich; Bertl, Willi; Deiters, Konrad; Erdmann, Wolfram; Gabathuler, Kurt; Horisberger, Roland; Ingram, Quentin; Kaestli, Hans-Christian; König, Stefan; Kotlinski, Danek; Langenegger, Urs; Meier, Frank; Renker, Dieter; Rohe, Tilman; Sibille, Jennifer; Starodumov, Andrei; Bortignon, Pierluigi; Caminada, Lea; Chen, Zhiling; Cittolin, Sergio; Dissertori, Günther; Dittmar, Michael; Eugster, Jürg; Freudenreich, Klaus; Grab, Christoph; Hervé, Alain; Hintz, Wieland; Lecomte, Pierre; Lustermann, Werner; Marchica, Carmelo; Martinez Ruiz del Arbol, Pablo; Meridiani, Paolo; Milenovic, Predrag; Moortgat, Filip; Nef, Pascal; Nessi-Tedaldi, Francesca; Pape, Luc; Pauss, Felicitas; Punz, Thomas; Rizzi, Andrea; Ronga, Frederic Jean; Rossini, Marco; Sala, Leonardo; Sanchez, Ann - Karin; Sawley, Marie-Christine; Stieger, Benjamin; Tauscher, Ludwig; Thea, Alessandro; Theofilatos, Konstantinos; Treille, Daniel; Urscheler, Christina; Wallny, Rainer; Weber, Matthias; Wehrli, Lukas; Weng, Joanna; Aguiló, Ernest; Amsler, Claude; Chiochia, Vincenzo; De Visscher, Simon; Favaro, Carlotta; Ivova Rikova, Mirena; Millan Mejias, Barbara; Regenfus, Christian; Robmann, Peter; Schmidt, Alexander; Snoek, Hella; Wilke, Lotte; Chang, Yuan-Hann; Chen, Kuan-Hsin; Chen, Wan-Ting; Dutta, Suchandra; Go, Apollo; Kuo, Chia-Ming; Li, Syue-Wei; Lin, Willis; Liu, Ming-Hsiung; Liu, Zong-Kai; Lu, Yun-Ju; Wu, Jing-Han; Yu, Shin-Shan; Bartalini, Paolo; Chang, Paoti; Chang, You-Hao; Chang, Yu-Wei; Chao, Yuan; Chen, Kai-Feng; Hou, George Wei-Shu; Hsiung, Yee; Kao, Kai-Yi; Lei, Yeong-Jyi; Lu, Rong-Shyang; Shiu, Jing-Ge; Tzeng, Yeng-Ming; Wang, Minzu; Adiguzel, Aytul; Bakirci, Mustafa Numan; Cerci, Salim; Dozen, Candan; Dumanoglu, Isa; Eskut, Eda; Girgis, Semiray; Gokbulut, Gul; Guler, Yalcin; Gurpinar, Emine; Hos, Ilknur; Kangal, Evrim Ersin; Karaman, Turker; Kayis Topaksu, Aysel; Nart, Alisah; Onengut, Gulsen; Ozdemir, Kadri; Ozturk, Sertac; Polatoz, Ayse; Sogut, Kenan; Tali, Bayram; Topakli, Huseyin; Uzun, Dilber; Vergili, Latife Nukhet; Vergili, Mehmet; Zorbilmez, Caglar; Akin, Ilina Vasileva; Aliev, Takhmasib; Bilmis, Selcuk; Deniz, Muhammed; Gamsizkan, Halil; Guler, Ali Murat; Ocalan, Kadir; Ozpineci, Altug; Serin, Meltem; Sever, Ramazan; Surat, Ugur Emrah; Yildirim, Eda; Zeyrek, Mehmet; Deliomeroglu, Mehmet; Demir, Durmus; Gülmez, Erhan; Halu, Arda; Isildak, Bora; Kaya, Mithat; Kaya, Ozlem; Ozkorucuklu, Suat; Sonmez, Nasuf; Levchuk, Leonid; Bell, Peter; Bostock, Francis; Brooke, James John; Cheng, Teh Lee; Clement, Emyr; Cussans, David; Frazier, Robert; Goldstein, Joel; Grimes, Mark; Hansen, Maria; Hartley, Dominic; Heath, Greg P.; Heath, Helen F.; Huckvale, Benedickt; Jackson, James; Kreczko, Lukasz; Metson, Simon; Newbold, Dave M.; Nirunpong, Kachanon; Poll, Anthony; Senkin, Sergey; Smith, Vincent J.; Ward, Simon; Basso, Lorenzo; Bell, Ken W.; Belyaev, Alexander; Brew, Christopher; Brown, Robert M.; Camanzi, Barbara; Cockerill, David J.A.; Coughlan, John A.; Harder, Kristian; Harper, Sam; Kennedy, Bruce W.; Olaiya, Emmanuel; Petyt, David; Radburn-Smith, Benjamin Charles; Shepherd-Themistocleous, Claire; Tomalin, Ian R.; Womersley, William John; Worm, Steven; Bainbridge, Robert; Ball, Gordon; Ballin, Jamie; Beuselinck, Raymond; Buchmuller, Oliver; Colling, David; Cripps, Nicholas; Cutajar, Michael; Davies, Gavin; Della Negra, Michel; Fulcher, Jonathan; Futyan, David; Guneratne Bryer, Arlo; Hall, Geoffrey; Hatherell, Zoe; Hays, Jonathan; Iles, Gregory; Karapostoli, Georgia; Lyons, Louis; Magnan, Anne-Marie; Marrouche, Jad; Nandi, Robin; Nash, Jordan; Nikitenko, Alexander; Papageorgiou, Anastasios; Pesaresi, Mark; Petridis, Konstantinos; Pioppi, Michele; Raymond, David Mark; Rompotis, Nikolaos; Rose, Andrew; Ryan, Matthew John; Seez, Christopher; Sharp, Peter; Sparrow, Alex; Tapper, Alexander; Tourneur, Stephane; Vazquez Acosta, Monica; Virdee, Tejinder; Wakefield, Stuart; Wardrope, David; Whyntie, Tom; Barrett, Matthew; Chadwick, Matthew; Cole, Joanne; Hobson, Peter R.; Khan, Akram; Kyberd, Paul; Leslie, Dawn; Martin, William; Reid, Ivan; Teodorescu, Liliana; Hatakeyama, Kenichi; Bose, Tulika; Carrera Jarrin, Edgar; Clough, Andrew; Fantasia, Cory; Heister, Arno; St. John, Jason; Lawson, Philip; Lazic, Dragoslav; Rohlf, James; Sperka, David; Sulak, Lawrence; Avetisyan, Aram; Bhattacharya, Saptaparna; Chou, John Paul; Cutts, David; Ferapontov, Alexey; Heintz, Ulrich; Jabeen, Shabnam; Kukartsev, Gennadiy; Landsberg, Greg; Narain, Meenakshi; Nguyen, Duong; Segala, Michael; Speer, Thomas; Tsang, Ka Vang; Borgia, Maria Assunta; Breedon, Richard; Calderon De La Barca Sanchez, Manuel; Cebra, Daniel; Chauhan, Sushil; Chertok, Maxwell; Conway, John; Cox, Peter Timothy; Dolen, James; Erbacher, Robin; Friis, Evan; Ko, Winston; Kopecky, Alexandra; Lander, Richard; Liu, Haidong; Maruyama, Sho; Miceli, Tia; Nikolic, Milan; Pellett, Dave; Robles, Jorge; Salur, Sevil; Schwarz, Thomas; Searle, Matthew; Smith, John; Squires, Michael; Tripathi, Mani; Vasquez Sierra, Ricardo; Veelken, Christian; Andreev, Valeri; Arisaka, Katsushi; Cline, David; Cousins, Robert; Deisher, Amanda; Duris, Joseph; Erhan, Samim; Farrell, Chris; Hauser, Jay; Ignatenko, Mikhail; Jarvis, Chad; Plager, Charles; Rakness, Gregory; Schlein, Peter; Tucker, Jordan; Valuev, Vyacheslav; Babb, John; Clare, Robert; Ellison, John Anthony; Gary, J William; Giordano, Ferdinando; Hanson, Gail; Jeng, Geng-Yuan; Kao, Shih-Chuan; Liu, Feng; Liu, Hongliang; Luthra, Arun; Nguyen, Harold; Pasztor, Gabriella; Satpathy, Asish; Shen, Benjamin C.; Stringer, Robert; Sturdy, Jared; Sumowidagdo, Suharyo; Wilken, Rachel; Wimpenny, Stephen; Andrews, Warren; Branson, James G.; Cerati, Giuseppe Benedetto; Dusinberre, Elizabeth; Evans, David; Golf, Frank; Holzner, André; Kelley, Ryan; Lebourgeois, Matthew; Letts, James; Mangano, Boris; Muelmenstaedt, Johannes; Padhi, Sanjay; Palmer, Christopher; Petrucciani, Giovanni; Pi, Haifeng; Pieri, Marco; Ranieri, Riccardo; Sani, Matteo; Sharma, Vivek; Simon, Sean; Tu, Yanjun; Vartak, Adish; Würthwein, Frank; Yagil, Avraham; Barge, Derek; Bellan, Riccardo; Campagnari, Claudio; D'Alfonso, Mariarosaria; Danielson, Thomas; Flowers, Kristen; Geffert, Paul; Incandela, Joe; Justus, Christopher; Kalavase, Puneeth; Koay, Sue Ann; Kovalskyi, Dmytro; Krutelyov, Vyacheslav; Lowette, Steven; Mccoll, Nickolas; Pavlunin, Viktor; Rebassoo, Finn; Ribnik, Jacob; Richman, Jeffrey; Rossin, Roberto; Stuart, David; To, Wing; Vlimant, Jean-Roch; Bornheim, Adolf; Bunn, Julian; Chen, Yi; Gataullin, Marat; Kcira, Dorian; Litvine, Vladimir; Ma, Yousi; Mott, Alexander; Newman, Harvey B.; Rogan, Christopher; Timciuc, Vladlen; Traczyk, Piotr; Veverka, Jan; Wilkinson, Richard; Yang, Yong; Zhu, Ren-Yuan; Akgun, Bora; Carroll, Ryan; Ferguson, Thomas; Iiyama, Yutaro; Jang, Dong Wook; Jun, Soon Yung; Liu, Yueh-Feng; Paulini, Manfred; Russ, James; Terentyev, Nikolay; Vogel, Helmut; Vorobiev, Igor; Cumalat, John Perry; Dinardo, Mauro Emanuele; Drell, Brian Robert; Edelmaier, Christopher; Ford, William T.; Heyburn, Bernadette; Luiggi Lopez, Eduardo; Nauenberg, Uriel; Smith, James; Stenson, Kevin; Ulmer, Keith; Wagner, Stephen Robert; Zang, Shi-Lei; Agostino, Lorenzo; Alexander, James; Chatterjee, Avishek; Das, Souvik; Eggert, Nicholas; Fields, Laura Johanna; Gibbons, Lawrence Kent; Heltsley, Brian; Hopkins, Walter; Khukhunaishvili, Aleko; Kreis, Benjamin; Kuznetsov, Valentin; Nicolas Kaufman, Gala; Patterson, Juliet Ritchie; Puigh, Darren; Riley, Daniel; Ryd, Anders; Shi, Xin; Sun, Werner; Teo, Wee Don; Thom, Julia; Thompson, Joshua; Vaughan, Jennifer; Weng, Yao; Winstrom, Lucas; Wittich, Peter; Biselli, Angela; Cirino, Guy; Winn, Dave; Abdullin, Salavat; Albrow, Michael; Anderson, Jacob; Apollinari, Giorgio; Atac, Muzaffer; Bakken, Jon Alan; Banerjee, Sunanda; Bauerdick, Lothar A.T.; Beretvas, Andrew; Berryhill, Jeffrey; Bhat, Pushpalatha C.; Bloch, Ingo; Borcherding, Frederick; Burkett, Kevin; Butler, Joel Nathan; Chetluru, Vasundhara; Cheung, Harry; Chlebana, Frank; Cihangir, Selcuk; Demarteau, Marcel; Eartly, David P.; Elvira, Victor Daniel; Esen, Selda; Fisk, Ian; Freeman, Jim; Gao, Yanyan; Gottschalk, Erik; Green, Dan; Gunthoti, Kranti; Gutsche, Oliver; Hahn, Alan; Hanlon, Jim; Harris, Robert M.; Hirschauer, James; Hooberman, Benjamin; James, Eric; Jensen, Hans; Johnson, Marvin; Joshi, Umesh; Khatiwada, Rakshya; Kilminster, Benjamin; Klima, Boaz; Kousouris, Konstantinos; Kunori, Shuichi; Kwan, Simon; Limon, Peter; Lipton, Ron; Lykken, Joseph; Maeshima, Kaori; Marraffino, John Michael; Mason, David; McBride, Patricia; McCauley, Thomas; Miao, Ting; Mishra, Kalanand; Mrenna, Stephen; Musienko, Yuri; Newman-Holmes, Catherine; O'Dell, Vivian; Popescu, Sorina; Pordes, Ruth; Prokofyev, Oleg; Saoulidou, Niki; Sexton-Kennedy, Elizabeth; Sharma, Seema; Soha, Aron; Spalding, William J.; Spiegel, Leonard; Tan, Ping; Taylor, Lucas; Tkaczyk, Slawek; Uplegger, Lorenzo; Vaandering, Eric Wayne; Vidal, Richard; Whitmore, Juliana; Wu, Weimin; Yang, Fan; Yumiceva, Francisco; Yun, Jae Chul; Acosta, Darin; Avery, Paul; Bourilkov, Dimitri; Chen, Mingshui; Di Giovanni, Gian Piero; Dobur, Didar; Drozdetskiy, Alexey; Field, Richard D.; Fisher, Matthew; Fu, Yu; Furic, Ivan-Kresimir; Gartner, Joseph; Goldberg, Sean; Kim, Bockjoo; Klimenko, Sergey; Konigsberg, Jacobo; Korytov, Andrey; Kropivnitskaya, Anna; Kypreos, Theodore; Matchev, Konstantin; Mitselmakher, Guenakh; Muniz, Lana; Pakhotin, Yuriy; Prescott, Craig; Remington, Ronald; Schmitt, Michael Houston; Scurlock, Bobby; Sellers, Paul; Skhirtladze, Nikoloz; Wang, Dayong; Yelton, John; Zakaria, Mohammed; Ceron, Cristobal; Gaultney, Vanessa; Kramer, Laird; Lebolo, Luis Miguel; Linn, Stephan; Markowitz, Pete; Martinez, German; Rodriguez, Jorge Luis; Adams, Todd; Askew, Andrew; Bandurin, Dmitry; Bochenek, Joseph; Chen, Jie; Diamond, Brendan; Gleyzer, Sergei V; Haas, Jeff; Hagopian, Sharon; Hagopian, Vasken; Jenkins, Merrill; Johnson, Kurtis F.; Prosper, Harrison; Sekmen, Sezen; Veeraraghavan, Venkatesh; Baarmand, Marc M.; Dorney, Brian; Guragain, Samir; Hohlmann, Marcus; Kalakhety, Himali; Ralich, Robert; Vodopiyanov, Igor; Adams, Mark Raymond; Anghel, Ioana Maria; Apanasevich, Leonard; Bai, Yuting; Bazterra, Victor Eduardo; Betts, Russell Richard; Callner, Jeremy; Cavanaugh, Richard; Dragoiu, Cosmin; Garcia-Solis, Edmundo Javier; Gerber, Cecilia Elena; Hofman, David Jonathan; Khalatyan, Samvel; Lacroix, Florent; O'Brien, Christine; Silvestre, Catherine; Smoron, Agata; Strom, Derek; Varelas, Nikos; Akgun, Ugur; Albayrak, Elif Asli; Bilki, Burak; Cankocak, Kerem; Clarida, Warren; Duru, Firdevs; Lae, Chung Khim; McCliment, Edward; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mestvirishvili, Alexi; Moeller, Anthony; Nachtman, Jane; Newsom, Charles Ray; Norbeck, Edwin; Olson, Jonathan; Onel, Yasar; Ozok, Ferhat; Sen, Sercan; Wetzel, James; Yetkin, Taylan; Yi, Kai; Barnett, Bruce Arnold; Blumenfeld, Barry; Bonato, Alessio; Eskew, Christopher; Fehling, David; Giurgiu, Gavril; Gritsan, Andrei; Guo, Zijin; Hu, Guofan; Maksimovic, Petar; Rappoccio, Salvatore; Swartz, Morris; Tran, Nhan Viet; Whitbeck, Andrew; Baringer, Philip; Bean, Alice; Benelli, Gabriele; Grachov, Oleg; Murray, Michael; Noonan, Daniel; Radicci, Valeria; Sanders, Stephen; Wood, Jeffrey Scott; Zhukova, Victoria; Bolton, Tim; Chakaberia, Irakli; Ivanov, Andrew; Makouski, Mikhail; Maravin, Yurii; Shrestha, Shruti; Svintradze, Irakli; Wan, Zongru; Gronberg, Jeffrey; Lange, David; Wright, Douglas; Baden, Drew; Boutemeur, Madjid; Eno, Sarah Catherine; Ferencek, Dinko; Gomez, Jaime; Hadley, Nicholas John; Kellogg, Richard G.; Kirn, Malina; Lu, Ying; Mignerey, Alice; Rossato, Kenneth; Rumerio, Paolo; Santanastasio, Francesco; Skuja, Andris; Temple, Jeffrey; Tonjes, Marguerite; Tonwar, Suresh C.; Twedt, Elizabeth; Alver, Burak; Bauer, Gerry; Bendavid, Joshua; Busza, Wit; Butz, Erik; Cali, Ivan Amos; Chan, Matthew; Dutta, Valentina; Everaerts, Pieter; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Hahn, Kristan Allan; Harris, Philip; Kim, Yongsun; Klute, Markus; Lee, Yen-Jie; Li, Wei; Loizides, Constantinos; Luckey, Paul David; Ma, Teng; Nahn, Steve; Paus, Christoph; Ralph, Duncan; Roland, Christof; Roland, Gunther; Rudolph, Matthew; Stephans, George; Sumorok, Konstanty; Sung, Kevin; Wenger, Edward Allen; Xie, Si; Yang, Mingming; Yilmaz, Yetkin; Yoon, Sungho; Zanetti, Marco; Cole, Perrie; Cooper, Seth; Cushman, Priscilla; Dahmes, Bryan; De Benedetti, Abraham; Dudero, Phillip Russell; Franzoni, Giovanni; Haupt, Jason; Klapoetke, Kevin; Kubota, Yuichi; Mans, Jeremy; Rekovic, Vladimir; Rusack, Roger; Sasseville, Michael; Singovsky, Alexander; Cremaldi, Lucien Marcus; Godang, Romulus; Kroeger, Rob; Perera, Lalith; Rahmat, Rahmat; Sanders, David A; Summers, Don; Bloom, Kenneth; Bose, Suvadeep; Butt, Jamila; Claes, Daniel R.; Dominguez, Aaron; Eads, Michael; Keller, Jason; Kelly, Tony; Kravchenko, Ilya; Lazo-Flores, Jose; Lundstedt, Carl; Malbouisson, Helena; Malik, Sudhir; Snow, Gregory R.; Baur, Ulrich; Godshalk, Andrew; Iashvili, Ia; Kharchilava, Avto; Kumar, Ashish; Shipkowski, Simon Peter; Smith, Kenneth; Alverson, George; Barberis, Emanuela; Baumgartel, Darin; Boeriu, Oana; Chasco, Matthew; Kaadze, Ketino; Reucroft, Steve; Swain, John; Wood, Darien; Zhang, Jinzhong; Anastassov, Anton; Kubik, Andrew; Odell, Nathaniel; Ofierzynski, Radoslaw Adrian; Pollack, Brian; Pozdnyakov, Andrey; Schmitt, Michael Henry; Stoynev, Stoyan; Velasco, Mayda; Won, Steven; Antonelli, Louis; Berry, Douglas; Hildreth, Michael; Jessop, Colin; Karmgard, Daniel John; Kolb, Jeff; Kolberg, Ted; Lannon, Kevin; Luo, Wuming; Lynch, Sean; Marinelli, Nancy; Morse, David Michael; Pearson, Tessa; Ruchti, Randy; Slaunwhite, Jason; Valls, Nil; Warchol, Jadwiga; Wayne, Mitchell; Ziegler, Jill; Bylsma, Ben; Durkin, Lloyd Stanley; Gu, Jianhui; Hill, Christopher; Killewald, Phillip; Kotov, Khristian; Ling, Ta-Yung; Rodenburg, Marissa; Williams, Grayson; Adam, Nadia; Berry, Edmund; Elmer, Peter; Gerbaudo, Davide; Halyo, Valerie; Hebda, Philip; Hunt, Adam; Jones, John; Laird, Edward; Lopes Pegna, David; Marlow, Daniel; Medvedeva, Tatiana; Mooney, Michael; Olsen, James; Piroué, Pierre; Quan, Xiaohang; Saka, Halil; Stickland, David; Tully, Christopher; Werner, Jeremy Scott; Zuranski, Andrzej; Acosta, Jhon Gabriel; Huang, Xing Tao; Lopez, Angel; Mendez, Hector; Oliveros, Sandra; Ramirez Vargas, Juan Eduardo; Zatserklyaniy, Andriy; Alagoz, Enver; Barnes, Virgil E.; Bolla, Gino; Borrello, Laura; Bortoletto, Daniela; Everett, Adam; Garfinkel, Arthur F.; Gecse, Zoltan; Gutay, Laszlo; Hu, Zhen; Jones, Matthew; Koybasi, Ozhan; Laasanen, Alvin T.; Leonardo, Nuno; Liu, Chang; Maroussov, Vassili; Merkel, Petra; Miller, David Harry; Neumeister, Norbert; Potamianos, Karolos; Shipsey, Ian; Silvers, David; Svyatkovskiy, Alexey; Yoo, Hwi Dong; Zablocki, Jakub; Zheng, Yu; Jindal, Pratima; Parashar, Neeti; Boulahouache, Chaouki; Cuplov, Vesna; Ecklund, Karl Matthew; Geurts, Frank J.M.; Liu, Jinghua H.; Morales, Jafet; Padley, Brian Paul; Redjimi, Radia; Roberts, Jay; Zabel, James; Betchart, Burton; Bodek, Arie; Chung, Yeon Sei; Covarelli, Roberto; de Barbaro, Pawel; Demina, Regina; Eshaq, Yossof; Flacher, Henning; Garcia-Bellido, Aran; Goldenzweig, Pablo; Gotra, Yury; Han, Jiyeon; Harel, Amnon; Miner, Daniel Carl; Orbaker, Douglas; Petrillo, Gianluca; Vishnevskiy, Dmitry; Zielinski, Marek; Bhatti, Anwar; Demortier, Luc; Goulianos, Konstantin; Lungu, Gheorghe; Mesropian, Christina; Yan, Ming; Atramentov, Oleksiy; Barker, Anthony; Duggan, Daniel; Gershtein, Yuri; Gray, Richard; Halkiadakis, Eva; Hidas, Dean; Hits, Dmitry; Lath, Amitabh; Panwalkar, Shruti; Patel, Rishi; Richards, Alan; Rose, Keith; Schnetzer, Steve; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Cerizza, Giordano; Hollingsworth, Matthew; Spanier, Stefan; Yang, Zong-Chang; York, Andrew; Asaadi, Jonathan; Eusebi, Ricardo; Gilmore, Jason; Gurrola, Alfredo; Kamon, Teruki; Khotilovich, Vadim; Montalvo, Roy; Nguyen, Chi Nhan; Osipenkov, Ilya; Pivarski, James; Safonov, Alexei; Sengupta, Sinjini; Tatarinov, Aysen; Toback, David; Weinberger, Michael; Akchurin, Nural; Bardak, Cemile; Damgov, Jordan; Jeong, Chiyoung; Kovitanggoon, Kittikul; Lee, Sung Won; Mane, Poonam; Roh, Youn; Sill, Alan; Volobouev, Igor; Wigmans, Richard; Yazgan, Efe; Appelt, Eric; Brownson, Eric; Engh, Daniel; Florez, Carlos; Gabella, William; Johns, Willard; Kurt, Pelin; Maguire, Charles; Melo, Andrew; Sheldon, Paul; Velkovska, Julia; Arenton, Michael Wayne; Balazs, Michael; Boutle, Sarah; Buehler, Marc; Conetti, Sergio; Cox, Bradley; Francis, Brian; Hirosky, Robert; Ledovskoy, Alexander; Lin, Chuanzhe; Neu, Christopher; Yohay, Rachel; Gollapinni, Sowjanya; Harr, Robert; Karchin, Paul Edmund; Lamichhane, Pramod; Mattson, Mark; Milstène, Caroline; Sakharov, Alexandre; Anderson, Michael; Bachtis, Michail; Bellinger, James Nugent; Carlsmith, Duncan; Dasu, Sridhara; Efron, Jonathan; Gray, Lindsey; Grogg, Kira Suzanne; Grothe, Monika; Hall-Wilton, Richard; Herndon, Matthew; Klabbers, Pamela; Klukas, Jeffrey; Lanaro, Armando; Lazaridis, Christos; Leonard, Jessica; Lomidze, David; Loveless, Richard; Mohapatra, Ajit; Reeder, Don; Ross, Ian; Savin, Alexander; Smith, Wesley H.; Swanson, Joshua; Weinberg, Marc

2011-01-01

The result of a search at the LHC for heavy stable charged particles produced in pp collisions at sqrt(s) = 7 TeV is described. The data sample was collected with the CMS detector and corresponds to an integrated luminosity of 3.1 inverse picobarns. Momentum and ionization-energy-loss measurements in the inner tracker detector are used to identify tracks compatible with heavy slow-moving particles. Additionally, tracks passing muon identification requirements are also analyzed for the same signature. In each case, no candidate passes the selection, with an expected background of less than 0.1 events. A lower limit at the 95% confidence level on the mass of a stable gluino is set at 398 GeV/c2, using a conventional model of nuclear interactions that allows charged hadrons containing this particle to reach the muon detectors. A lower limit of 311 GeV/c2 is also set for a stable gluino in a conservative scenario of complete charge suppression, where any hadron containing this particle becomes neutral before rea...

Detonation of Meta-stable Clusters

Energy Technology Data Exchange (ETDEWEB)

Kuhl, Allen; Kuhl, Allen L.; Fried, Laurence E.; Howard, W. Michael; Seizew, Michael R.; Bell, John B.; Beckner, Vincent; Grcar, Joseph F.

2008-05-31

We consider the energy accumulation in meta-stable clusters. This energy can be much larger than the typical chemical bond energy (~;;1 ev/atom). For example, polymeric nitrogen can accumulate 4 ev/atom in the N8 (fcc) structure, while helium can accumulate 9 ev/atom in the excited triplet state He2* . They release their energy by cluster fission: N8 -> 4N2 and He2* -> 2He. We study the locus of states in thermodynamic state space for the detonation of such meta-stable clusters. In particular, the equilibrium isentrope, starting at the Chapman-Jouguet state, and expanding down to 1 atmosphere was calculated with the Cheetah code. Large detonation pressures (3 and 16 Mbar), temperatures (12 and 34 kilo-K) and velocities (20 and 43 km/s) are a consequence of the large heats of detonation (6.6 and 50 kilo-cal/g) for nitrogen and helium clusters respectively. If such meta-stable clusters could be synthesized, they offer the potential for large increases in the energy density of materials.

Facile synthesis of high-temperature (1000 °C) phase-stable rice-like anatase TiO{sub 2} nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Lv, Lizhen [Capital Normal University, Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry (China); Chen, Qirong [Beijing Center for Physical and Chemical Analysis (BCPCA) (China); Liu, Xiuyun; Wang, Miaomiao; Meng, Xiangfu, E-mail: xfmeng@cnu.edu.cn [Capital Normal University, Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry (China)

2015-05-15

High-temperature phase-stable rice-like anatase TiO{sub 2} nanocrystals were synthesized by one-pot solvothermal method using soluble titania xerogel and isopropyl alcohol (IPA) as the precursor and the solvent, respectively. Sample characterization was carried out by powder X-ray diffraction, high-resolution transmission electron microscopy, field emission scanning electron microscope, X-ray photoelectron spectroscopy, and N{sub 2} adsorption–desorption isotherms. The results showed that TiO{sub 2} nanocrystals had rice-like shapes with an average size of 5 nm in width and 35 nm in length. The BET surface area was 153 m{sup 2}/g. Unexpectedly, the rice-like TiO{sub 2} nanocrystals exhibited high-temperature phase stability, which could remain as pure anatase phase after calcinations at 1000 °C. Growth mechanism investigation revealed that the IPA solvent played a key role in nucleation and growth of rice-like anatase TiO{sub 2} nanocrystals. The photodegradation of rhodamine B demonstrated that rice-like anatase TiO{sub 2} nanocrystals exhibited enhanced photocatalytic activity under visible light irradiation.

Perspective: Highly stable vapor-deposited glasses

Science.gov (United States)

Ediger, M. D.

2017-12-01

This article describes recent progress in understanding highly stable glasses prepared by physical vapor deposition and provides perspective on further research directions for the field. For a given molecule, vapor-deposited glasses can have higher density and lower enthalpy than any glass that can be prepared by the more traditional route of cooling a liquid, and such glasses also exhibit greatly enhanced kinetic stability. Because vapor-deposited glasses can approach the bottom of the amorphous part of the potential energy landscape, they provide insights into the properties expected for the "ideal glass." Connections between vapor-deposited glasses, liquid-cooled glasses, and deeply supercooled liquids are explored. The generality of stable glass formation for organic molecules is discussed along with the prospects for stable glasses of other types of materials.

Trophic niches of sympatric tropical tuna in the Western Indian Ocean inferred by stable isotopes and neutral fatty acids

Science.gov (United States)

Sardenne, Fany; Bodin, Nathalie; Chassot, Emmanuel; Amiel, Aurélien; Fouché, Edwin; Degroote, Maxime; Hollanda, Stéphanie; Pethybridge, Heidi; Lebreton, Benoit; Guillou, Gaël; Ménard, Frédéric

2016-08-01

This study examined the trophic ecology of three sympatric tropical tuna species (bigeye BET, skipjack SKJ, and yellowfin YFT) sampled in the Western Indian Ocean throughout 2013. Specifically we explored inter-specific resource partitioning and ontogenetic variability using neutral fatty acids and stable isotope analysis of liver and muscle from small (⩽100 cm fork length, FL) and large (>100 cm FL) tuna collected in mixed schools at the surface by purse-seine. Both biochemical tracers were used to calculate trophic niche indices that collectively revealed high potential for resource overlap, especially among small tuna. Resource overlap appeared strongest between BET and YFT, with SKJ tissues having high carbon isotope (δ13C) values (-17 ± 0.3‰), lower nitrogen isotope (δ15N) values (11.4 ± 0.6‰), and higher relative proportion of poly-unsaturated fatty acids (PUFA) than the two other species, indicating a different diet. Size was found to be a strong predictor for most biochemical tracers in the three species with δ13C, δ15N and total lipid content in the liver. In the larger species (YFT and BET), proportions of mono-unsaturated fatty acids typically increased with size, while quantities of PUFA decreased. In addition to ontogenetic variability, trophic markers were shown to vary between sampling area and season: higher lipid reserves and δ15N values, and lower δ13C values occurred during monsoon periods around Seychelles than in the Mozambique Channel (parted from about 1500 km). Our multi-tracer approach reveals the magnitude of potential competitive interactions in mixed tropical tuna schools at both small and large sizes and demonstrates that ontogenetic niche differentiation acts as a major factor of coexistence in tropical tuna.

Assessment of dust sampling methods for the study of cultivable-microorganism exposure in stables.

NARCIS (Netherlands)

Normand, A.C.; Vacheyrou, M.; Sudre, B.; Heederik, D.|info:eu-repo/dai/nl/072910542; Piarroux, R.

2009-01-01

Studies have shown a link between living on a farm, exposure to microbial components (e.g., endotoxins or beta-d-glucans), and a lower risk for allergic diseases and asthma. Due to the lack of validated sampling methods, studies of asthma and atopy have not relied on exposure assessment based on

Myocardial perfusion SPECT in stable angina;Place de la scintigraphie myocardique dans l'angor stable

Energy Technology Data Exchange (ETDEWEB)

Jau, P.; Jacob, T. [HP Clairval, Service de medecine nucleaire, 13 - Marseille (France); Lecorff, G.; Bouvier, J.L.; Novella, P.; Bechet, V.; Pelet, V. [HP Clairval, Service de cardiologie, 13 - Marseille (France)

2010-03-15

We study the precise contribution of myocardial scintigraphy in the therapeutic management of stable coronary artery disease. Until recently, treatment was focused on revascularization, often by coronary angioplasty.Recent studies have challenged this practice by showing the absence of superiority of angioplasty compared to optimal medical therapy.The problem now is to define for each stable coronary artery disease, and individually, the best of both treatment options. In this spirit, the functional approach to coronary artery disease by myocardial perfusion scintigraphy is most interesting.The diagnostic performance, including sensitivity and negative predictive value, and the prognostic value of the technique are clearly established. Recent studies show that a therapeutic decision based on a functional approach to the patient is valid.We need to know this development in cardiology for best position in the multidisciplinary discussions, myocardial scintigraphy as a functional approach to stable coronary artery disease. (N.C.)

Trophic structure of mesopelagic fishes in the Gulf of Mexico revealed by gut content and stable isotope analyses

Science.gov (United States)

McClain-Counts, Jennifer P.; Demopoulos, Amanda W.J.; Ross, Steve W.

2017-01-01

Mesopelagic fishes represent an important component of the marine food web due to their global distributions, high abundances and ability to transport organic material throughout a large part of the water column. This study combined stable isotope (SIAs) and gut content analyses (GCAs) to characterize the trophic structure of mesopelagic fishes in the North-Central Gulf of Mexico. Additionally, this study examined whether mesopelagic fishes utilized chemosynthetic energy from cold seeps. Specimens were collected (9–25 August 2007) over three deep (>1,000 m) cold seeps at discrete depths (surface to 1,503 m) over the diurnal cycle. GCA classified 31 species (five families) of mesopelagic fishes into five feeding guilds: piscivores, large crustacean consumers, copepod consumers, generalists and mixed zooplanktivores. However, these guilds were less clearly defined based on stable isotope mixing model (MixSIAR) results, suggesting diets may be more mixed over longer time periods (weeks–months) and across co-occurring species. Copepods were likely important for the majority of mesopelagic fishes, consistent with GCA (this study) and previous literature. MixSIAR results also identified non-crustacean prey items, including salps and pteropods, as potentially important prey items for mesopelagic fishes, including those fishes not analysed in GCA (Sternoptyx spp. and Melamphaidae). Salps and other soft-bodied species are often missed in GCAs. Mesopelagic fishes had δ13C results consistent with particulate organic matter serving as the baseline organic carbon source, fueling up to three trophic levels. Fishes that undergo diel vertical migration were depleted in 15N relative to weak migrators, consistent with depth-specific isotope trends in sources and consumers, and assimilation of 15N-depleted organic matter in surface waters. Linear correlations between fish size and δ15N values suggested ontogenetic changes in fish diets for several species. While there was

Stable Tetraquarks

Energy Technology Data Exchange (ETDEWEB)

Quigg, Chris [Fermilab

2018-04-13

For very heavy quarks, relations derived from heavy-quark symmetry imply novel narrow doubly heavy tetraquark states containing two heavy quarks and two light antiquarks. We predict that double-beauty states will be stable against strong decays, whereas the double-charm states and mixed beauty+charm states will dissociate into pairs of heavy-light mesons. Observing a new double-beauty state through its weak decays would establish the existence of tetraquarks and illuminate the role of heavy color-antitriplet diquarks as hadron constituents.

Stable isotope tracking of endangered sea turtles: validation with satellite telemetry and δ15N analysis of amino acids.

Directory of Open Access Journals (Sweden)

Jeffrey A Seminoff

Full Text Available Effective conservation strategies for highly migratory species must incorporate information about long-distance movements and locations of high-use foraging areas. However, the inherent challenges of directly monitoring these factors call for creative research approaches and innovative application of existing tools. Highly migratory marine species, such as marine turtles, regularly travel hundreds or thousands of kilometers between breeding and feeding areas, but identification of migratory routes and habitat use patterns remains elusive. Here we use satellite telemetry in combination with compound-specific isotope analysis of amino acids to confirm that insights from bulk tissue stable isotope analysis can reveal divergent migratory strategies and within-population segregation of foraging groups of critically endangered leatherback sea turtles (Dermochelys coriacea across the Pacific Ocean. Among the 78 turtles studied, we found a distinct dichotomy in δ(15N values of bulk skin, with distinct "low δ(15N" and "high δ(15N" groups. δ(15N analysis of amino acids confirmed that this disparity resulted from isotopic differences at the base of the food chain and not from differences in trophic position between the two groups. Satellite tracking of 13 individuals indicated that their bulk skin δ(15N value was linked to the particular foraging region of each turtle. These findings confirm that prevailing marine isoscapes of foraging areas can be reflected in the isotopic compositions of marine turtle body tissues sampled at nesting beaches. We use a Bayesian mixture model to show that between 82 and 100% of the 78 skin-sampled turtles could be assigned with confidence to either the eastern Pacific or western Pacific, with 33 to 66% of all turtles foraging in the eastern Pacific. Our forensic approach validates the use of stable isotopes to depict leatherback turtle movements over broad spatial ranges and is timely for establishing wise conservation

Stable isotope tracking of endangered sea turtles: validation with satellite telemetry and δ15N analysis of amino acids.

Science.gov (United States)

Seminoff, Jeffrey A; Benson, Scott R; Arthur, Karen E; Eguchi, Tomoharu; Dutton, Peter H; Tapilatu, Ricardo F; Popp, Brian N

2012-01-01

Effective conservation strategies for highly migratory species must incorporate information about long-distance movements and locations of high-use foraging areas. However, the inherent challenges of directly monitoring these factors call for creative research approaches and innovative application of existing tools. Highly migratory marine species, such as marine turtles, regularly travel hundreds or thousands of kilometers between breeding and feeding areas, but identification of migratory routes and habitat use patterns remains elusive. Here we use satellite telemetry in combination with compound-specific isotope analysis of amino acids to confirm that insights from bulk tissue stable isotope analysis can reveal divergent migratory strategies and within-population segregation of foraging groups of critically endangered leatherback sea turtles (Dermochelys coriacea) across the Pacific Ocean. Among the 78 turtles studied, we found a distinct dichotomy in δ(15)N values of bulk skin, with distinct "low δ(15)N" and "high δ(15)N" groups. δ(15)N analysis of amino acids confirmed that this disparity resulted from isotopic differences at the base of the food chain and not from differences in trophic position between the two groups. Satellite tracking of 13 individuals indicated that their bulk skin δ(15)N value was linked to the particular foraging region of each turtle. These findings confirm that prevailing marine isoscapes of foraging areas can be reflected in the isotopic compositions of marine turtle body tissues sampled at nesting beaches. We use a Bayesian mixture model to show that between 82 and 100% of the 78 skin-sampled turtles could be assigned with confidence to either the eastern Pacific or western Pacific, with 33 to 66% of all turtles foraging in the eastern Pacific. Our forensic approach validates the use of stable isotopes to depict leatherback turtle movements over broad spatial ranges and is timely for establishing wise conservation efforts in

Stable isotopes of carbon and nitrogen as markers of dietary variation among sociocultural subgroups of Inuit in Greenland

DEFF Research Database (Denmark)

Bjerregaard, Peter; Larsen, Christina V L; Dahl-Petersen, Inger K

2017-01-01

OBJECTIVES: We assessed the use of stable isotopes of carbon and nitrogen as biomarkers for traditional versus store-bought food among the Inuit. Furthermore, we compared the isotope patterns among sociocultural population groups. METHODS: As a part of a country-wide health survey in Greenland...... food in the diet was estimated at 21% from the mean δ(13) C value, 25% from the mean δ(15) N value, and 23% from the FFQ. CONCLUSION: Nail samples for analysis of stable isotopes of carbon and nitrogen were convenient to collect during a large population health survey among the Inuit. Isotope...

Development of stable isotope manufacturing in Russia

International Nuclear Information System (INIS)

Pokidychev, A.; Pokidycheva, M.

1999-01-01

For the past 25 years, Russia has relied heavily on the electromagnetic separation process for the production of middle and heavy mass stable isotopes. The separation of most light isotopes had been centered in Georgia which, after the collapse of the USSR, left Russia without this capability. In the mid-1970s, development of centrifuge technology for the separation of stable isotopes was begun. Alternative techniques such as laser separation, physical-chemical methods, and ion cyclotron resonance have also been investigated. Economic considerations have played a major role in the development and current status of the stable isotope enrichment capabilities of Russia

The Core Gut Microbiome of the American Cockroach, Periplaneta americana, Is Stable and Resilient to Dietary Shifts.

Science.gov (United States)

Tinker, Kara A; Ottesen, Elizabeth A

2016-11-15

The omnivorous cockroach Periplaneta americana hosts a diverse hindgut microbiota encompassing hundreds of microbial species. In this study, we used 16S rRNA gene sequencing to examine the effect of diet on the composition of the P. americana hindgut microbial community. Results show that the hindgut microbiota of P. americana exhibit a highly stable core microbial community with low variance in compositions between individuals and minimal community change in response to dietary shifts. This core hindgut microbiome is shared between laboratory-hosted and wild-caught individuals, although wild-caught specimens exhibited a higher diversity of low-abundance microbes that were lost following extended cultivation under laboratory conditions. This taxonomic stability strongly contrasts with observations of the gut microbiota of mammals, which have been shown to be highly responsive to dietary change. A comparison of P. americana hindgut samples with human fecal samples indicated that the cockroach hindgut community exhibited higher alpha diversity but a substantially lower beta diversity than the human gut microbiome. This suggests that cockroaches have evolved unique mechanisms for establishing and maintaining a diverse and stable core microbiome. The gut microbiome plays an important role in the overall health of its host. A healthy gut microbiota typically assists with defense against pathogens and the digestion and absorption of nutrients from food, while dysbiosis of the gut microbiota has been associated with reduced health. In this study, we examined the composition and stability of the gut microbiota from the omnivorous cockroach Periplaneta americana. We found that P. americana hosts a diverse core gut microbiome that remains stable after drastic long-term changes in diet. While other insects, notably ant and bee species, have evolved mechanisms for maintaining a stable association with specific gut microbiota, these insects typically host low-diversity gut

Self-esteem Is Mostly Stable Across Young Adulthood: Evidence from Latent STARTS Models.

Science.gov (United States)

Wagner, Jenny; Lüdtke, Oliver; Trautwein, Ulrich

2016-08-01

How stable is self-esteem? This long-standing debate has led to different conclusions across different areas of psychology. Longitudinal data and up-to-date statistical models have recently indicated that self-esteem has stable and autoregressive trait-like components and state-like components. We applied latent STARTS models with the goal of replicating previous findings in a longitudinal sample of young adults (N = 4,532; Mage  = 19.60, SD = 0.85; 55% female). In addition, we applied multigroup models to extend previous findings on different patterns of stability for men versus women and for people with high versus low levels of depressive symptoms. We found evidence for the general pattern of a major proportion of stable and autoregressive trait variance and a smaller yet substantial amount of state variance in self-esteem across 10 years. Furthermore, multigroup models suggested substantial differences in the variance components: Females showed more state variability than males. Individuals with higher levels of depressive symptoms showed more state and less autoregressive trait variance in self-esteem. Results are discussed with respect to the ongoing trait-state debate and possible implications of the group differences that we found in the stability of self-esteem. © 2015 Wiley Periodicals, Inc.

Stable isotope ratio measurements on highly enriched water samples by means of laser spectrometry

NARCIS (Netherlands)

van Trigt, R; Kerstel, E.R.T.; Visser, GH; Meijer, H.A.J.

2001-01-01

We demonstrate the feasibility of using laser spectrometry (LS) to analyze isotopically highly enriched water samples (i.e., delta H-2 less than or equal to 15000 parts per thousand, delta O-18 less than or equal to 1200 parts per thousand), as often used in the biomedical doubly labeled water (DLW)

Stable isotope composition of surface and groundwater in Baja California, Mexico

International Nuclear Information System (INIS)

Kretzschmar, Thomas G.; Frommen, Theresa

2013-01-01

Based on a total of 135 stable isotope analysis (δ 18 O, δD) carried out on surface and groundwater samples, as well as on rainwater samples between 2004 and 2011 in 5 different regions in Baja California, an isotopic evaluation of the region was established. The results showed a depletion gradient of -0.25 0/00 δ 18 O per 100 m rise in elevation throughout the study area. Considering an unaltered δ 18 O signature for the thermal springs, the recharge areas of these waters are at elevations over 1400 m outside of the present watersheds, indicating the presence of regional flow systems next to the local flow regime feeding the cold springs and wells. The Mesa de Andrade area has a completely different signature with values of -105 for δ 18 O and -13 for δD. (authors)

Isolation of a Moderately Stable but Sensitive Zwitterionic Diazonium Tetrazolyl-1,2,3-triazolate.

Science.gov (United States)

Klapötke, Thomas M; Krumm, Burkhard; Pflüger, Carolin

2016-07-15

An unexpected formation of a diazonium compound was observed by nitration of an amino substituted triazolyl tetrazole with mixed acid. The crystal structure determination revealed a zwitterionic diazonium tetrazolyl-1,2,3-triazolate, whose constitution was supported by NMR and vibrational spectroscopic analysis. The thermal stability and sensitivity toward impact and friction were determined. In contrast, diazotriazoles are rather unstable and are mainly handled in solution and/or low temperatures, which is not the case for this diazonium tetrazolyl-1,2,3-triazolate, being stable at ambient temperature.

Application of stable isotope analysis to study temporal changes in foraging ecology in a highly endangered amphibian.

Directory of Open Access Journals (Sweden)

J Hayley Gillespie

Full Text Available Understanding dietary trends for endangered species may be essential to assessing the effects of ecological disturbances such as habitat modification, species introductions or global climate change. Documenting temporal variation in prey selection may also be crucial for understanding population dynamics. However, the rarity, secretive behaviours and obscure microhabitats of some endangered species can make direct foraging observations difficult or impossible. Furthermore, the lethality or invasiveness of some traditional methods of dietary analysis (e.g. gut contents analysis, gastric lavage makes them inappropriate for such species. Stable isotope analysis facilitates non-lethal, indirect analysis of animal diet that has unrealized potential in the conservation of endangered organisms, particularly amphibians.I determined proportional contributions of aquatic macroinvertebrate prey to the diet of an endangered aquatic salamander Eurycea sosorum over a two-year period using stable isotope analysis of (13/12C and (15/14N and the Bayesian stable isotope mixing model SIAR. I calculated Strauss' dietary electivity indices by comparing these proportions with changing relative abundance of potential prey species through time. Stable isotope analyses revealed that a previously unknown prey item (soft-bodied planarian flatworms in the genus Dugesia made up the majority of E. sosorum diet. Results also demonstrate that E. sosorum is an opportunistic forager capable of diet switching to include a greater proportion of alternative prey when Dugesia populations decline. There is also evidence of intra-population dietary variation.Effective application of stable isotope analysis can help circumvent two key limitations commonly experienced by researchers of endangered species: the inability to directly observe these species in nature and the invasiveness or lethality of traditional methods of dietary analysis. This study illustrates the feasibility of stable

[Current Treatment of Stable Angina].

Science.gov (United States)

Toggweiler, Stefan; Jamshidi, Peiman; Cuculi, Florim

2015-06-17

Current therapy for stable angina includes surgical and percutaneous revascularization, which has been improved tremendously over the last decades. Smoking cessation and regular exercise are the cornerstone for prevention of further cerebrovascular events. Medical treatment includes treatment of cardiovascular risk factors and antithrombotic management, which can be a challenge in some patients. Owing to the fact the coronary revascularization is readily accessible these days in many industrialized countries, the importance of antianginal therapy has decreased over the past years. This article presents a contemporary overview of the management of patients with stable angina in the year 2015.

Stable Isotope Analysis Reveals That Agricultural Habitat Provides an Important Dietary Component for Nonbreeding Dunlin

Directory of Open Access Journals (Sweden)

Lesley Joan Evans Ogden

2005-12-01

Full Text Available Although shorebirds spending the winter in temperate areas frequently use estuarine and supratidal (upland feeding habitats, the relative contribution of each habitat to individual diets has not been directly quantified. We quantified the proportional use that Calidris alpina pacifica (Dunlin made of estuarine vs. terrestrial farmland resources on the Fraser River Delta, British Columbia, using stable isotope analysis (δ13C, δ15N of blood from 268 Dunlin over four winters, 1997 through 2000. We tested for individual, age, sex, morphological, seasonal, and weather-related differences in dietary sources. Based on single- (δ13C and dual-isotope mixing models, the agricultural habitat contributed approximately 38% of Dunlin diet averaged over four winters, with the balance from intertidal flats. However, there was a wide variation among individuals in the extent of agricultural feeding, ranging from about 1% to 95% of diet. Younger birds had a significantly higher terrestrial contribution to diet (43% than did adults (35%. We estimated that 6% of adults and 13% of juveniles were obtaining at least 75% of their diet from terrestrial sources. The isotope data provided no evidence for sex or overall body size effects on the proportion of diet that is terrestrial in origin. The use of agricultural habitat by Dunlin peaked in early January. Adult Dunlin obtained a greater proportion of their diet terrestrially during periods of lower temperatures and high precipitation, whereas no such relationship existed for juveniles. Seasonal variation in the use of agricultural habitat suggests that it is used more during energetically stressful periods. The terrestrial farmland zone appears to be consistently important as a habitat for juveniles, but for adults it may provide an alternative feeding site used as a buffer against starvation during periods of extreme weather. Loss or reduction of agricultural habitat adjacent to estuaries may negatively impact

Stable SU(5) monopoles with higher magnetic charge

International Nuclear Information System (INIS)

Miyamoto, S.; Sato, H.; Tomohiro, S.

1985-01-01

Taking into account the electroweak breaking effects, some multiply charged monopoles were shown to be stable by Gardner and Harvey. We give the explicit Ansa$uml: tze for finite-energy, nonsingular solutions of these stable higher-strength monopoles with eg = 1,(3/2),3. We also give the general stability conditions and the detailed behavior of the interaction potentials between two monopoles which produce the stable higher-strength monopoles

The behavior of radioactive 137Cs and stable Cs at the isolated undisturbed mountain pond in Fukui, Japan

International Nuclear Information System (INIS)

Iwamoto, Kazumi; Kimura, Makio; Ando, Kenji; Amano, Hikaru

2003-01-01

The behavior of radioactive 137 Cs and stable Cs at the isolated undisturbed mountain pond in Fukui, Japan was studied for the pond water, the sedimentary grains and the soil near the pond. The concentrations of 137 Cs and stable Cs in the pond water ranged from 0.23 to 0.85 Bq/m 3 and from 0.005 to 0.018 mg/m 3 , respectively. The sedimentary grains were sorted by sieving into fractions with diameter from 2 mm to less than 38 μm. The concentrations of 137 Cs and stable Cs in the sorted grains were measured, and those of the adsorbed state were determined by subtracting the concentration of the grain matrix. The adsorbed concentrations increased with decrease in particle diameter and depended less on the kind of samples. The in-situ distribution coefficient Kd depended largely on particle diameter and increased with the decrease in diameter. The values of Kd ranged from about 20 to 1200 m 3 /kg for stable Cs and about 15 to 1000 m 3 /kg for 137 Cs, and the Kd of 137 Cs seemed to be slightly smaller than that of stable Cs. The concentration of stable Cs in the sedimentary mud was found to be close to that of the fine grains. The concentrations of stable Cs in the soil near the pond was about 7.7 mg/kg, and that of 137 Cs was about 0.6 kBq/kg for the surface layer soil and decreased with increase in soil depth. (author)

Study and validity of 13C stable carbon isotopic ratio analysis by mass spectrometry and 2H site-specific natural isotopic fractionation by nuclear magnetic resonance isotopic measurements to characterize and control the authenticity of honey

International Nuclear Information System (INIS)

Cotte, J.F.; Casabianca, H.; Lheritier, J.; Perrucchietti, C.; Sanglar, C.; Waton, H.; Grenier-Loustalot, M.F.

2007-01-01

Honey samples were analyzed by stable carbon isotopic ratio analysis by mass spectrometry (SCIRA-MS) and site-specific natural isotopic fractionation measured by nuclear magnetic resonance (SNIF-NMR) to first determine their potentials for characterizing the substance and then to combat adulteration. Honey samples from several geographic and botanical origins were analyzed. The δ 13 C parameter was not significant for characterizing an origin, while the (D/H) I ratio could be used to differentiate certain single-flower varieties. Application of the official control method of adding a C 4 syrup (AOAC official method 998.12) to our authentic samples revealed anomalies resulting from SCIRA indices that were more negative than -1 per mille (permil). A filtration step was added to the experimental procedure and provided results that were compliant with Natural origin of our honey samples. In addition, spiking with a C 4 syrup could be detected starting at 9-10%. The use of SNIF-NMR is limited by the detection of a syrup spike starting only at 20%, which is far from satisfying

Stable isotopes and biomarkers in microbial ecology

NARCIS (Netherlands)

Boschker, H.T.S.; Middelburg, J.J.

2002-01-01

The use of biomarkers in combination with stable isotope analysis is a new approach in microbial ecology and a number of papers on a variety of subjects have appeared. We will first discuss the techniques for analysing stable isotopes in biomarkers, primarily gas chromatography-combustion-isotope

Malaria infection during pregnancy in area of stable transmission ...

African Journals Online (AJOL)

Malaria infection during pregnancy in area of stable transmission. ... (LBW), a leading cause of neonatal death in areas of stable malaria transmission. ... areas of stable malaria transmission and the effective strategies for prevention and control. Keywords: malaria, pregnancy, semi-immune women, anaemia, low birthweight

Experimental and numerical investigations of stable crack growth of axial surface flaws in a pressure vessel

International Nuclear Information System (INIS)

Brocks, W.; Krafka, H.; Mueller, W.; Wobst, K.

1988-01-01

In connection with the problem of the transferability of parameters obtained experimentally with the help of fracture-mechanical test specimens and used for the initiation and the stable propagation of cracks in cases of pulsating stress and of the elasto-plastic behaviour of construction components, a pressure vessel with an inside diameter of 1500 mm, a cylindrical length of 3000 mm and a wall thickness of 40 mm was hydraulically loaded with the help of internal pressure in the first stage, to attain an average crack growth of 1 mm at Δ a ≅, the loading taking place at about 21deg C. This stress-free annealed vessel exhibited an axial semielliptical vibration-induced surface crack about 181 mm long and 20 mm deep, as a test defect, in a welded circular blank made of the steel 20MnMoNi 55. The fractographic analysis of the first stable crack revealed that its growth rate of Δa was highest in the area of transition from the weak to the strong bend of the crack front (55deg m /σ v (average principal stress: σ m , Mises' reference stress: σ v v). A comparison of the experimental with the numerical results from the first stable crack shows that the local stable crack growth Δa cannot be calculated solely with reference to J, because Δa appears to depend essentially on the quotient σ m /σ v . (orig./MM) [de

Toward air-stable multilayer phosphorene thin-films and transistors

Science.gov (United States)

Kim, Joon-Seok; Liu, Yingnan; Zhu, Weinan; Kim, Seohee; Wu, Di; Tao, Li; Dodabalapur, Ananth; Lai, Keji; Akinwande, Deji

2015-01-01

Few-layer black phosphorus (BP), also known as phosphorene, is poised to be the most attractive graphene analogue owing to its high mobility approaching that of graphene, and its thickness-tunable band gap that can be as large as that of molybdenum disulfide. In essence, phosphorene represents the much sought after high-mobility, large direct band gap two-dimensional layered crystal that is ideal for optoelectronics and flexible devices. However, its instability in air is of paramount concern for practical applications. Here, we demonstrate air-stable BP devices with dielectric and hydrophobic encapsulation. Microscopy, spectroscopy, and transport techniques were employed to elucidate the aging mechanism, which can initiate from the BP surface for bare samples, or edges for samples with thin dielectric coating, highlighting the ineffectiveness of conventional scaled dielectrics. Our months-long studies indicate that a double layer capping of Al2O3 and hydrophobic fluoropolymer affords BP devices and transistors with indefinite air-stability for the first time, overcoming a critical material challenge for applied research and development. PMID:25758437

Dynamic Risk Assessment of Sexual Offenders: Validity and Dimensional Structure of the Stable-2007.