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Sample records for relative isotopic abundances

  1. Xe isotopic abundances in enstatite meteorites and relations to other planetary reservoirs

    International Nuclear Information System (INIS)

    Lee, Jee-Yon; Marti, Kurt; Wacker, John F.

    2009-01-01

    This paper describes the interpretation of xenon that was measured in the Abee meteorite. Reported Xe isotopic abundances in enstatite chondrites (EC's) show some variability, and this makes comparisons to other solar system reservoirs rather difficult. In contrast, we find uniform Xe isotopic abundances in the EC chondrite Abee for a variety of clasts, except for 128 Xe and 129 Xe, the isotopes affected by neutron capture in I and by extinct 129 I. We report averages for the studied clasts which are consistent within error limits with OC-Xe and with the Q-Xe signature. On the other hand, the elemental abundance ratios Ar/Xe are variable between clasts. A strongly reducing environment which is indicated for enstatite meteorites was generally assumed to be consistent with conditions existing in the early inner solar system. Xe isotopic abundances in SNC meteorites from Mars and also those in some terrestrial wells show that distinct isotopic reservoirs coexisted on the same planets. In particular, the Xe isotopic signatures in terrestrial well gases show the presence of a minor distinct component in two of the reported four well gases. These authors suggested that the extra component represents solar Xe, but we show that also a meteoritic xenon reservoir of the Abee-Xe structure is an option. The reported Xe data in Ar-rich (subsolar) EC's show isotopic abundances slightly lighter than those in Abee-Xe, but the relative abundances of Ar, Kr, and Xe indicate only a minor component of elementally unfractionated solar Xe. The elemental ratios suggest rather a different origin for these gases: the loading of solar particles into grain surfaces during exposure at elevated temperatures during accretion of matter in the inner solar system. A model of this type was suggested for the accretion of gases now observed in the atmosphere on Venus. We note that disks of crystalline silicates (including enstatite and olivine) have been observed in T Tauri stars during their early

  2. Absolute isotopic abundances of Ti in meteorites

    International Nuclear Information System (INIS)

    Niederer, F.R.; Papanastassiou, D.A.; Wasserburg, G.J.

    1985-01-01

    The absolute isotope abundance of Ti has been determined in Ca-Al-rich inclusions from the Allende and Leoville meteorites and in samples of whole meteorites. The absolute Ti isotope abundances differ by a significant mass dependent isotope fractionation transformation from the previously reported abundances, which were normalized for fractionation using 46 Ti/ 48 Ti. Therefore, the absolute compositions define distinct nucleosynthetic components from those previously identified or reflect the existence of significant mass dependent isotope fractionation in nature. We provide a general formalism for determining the possible isotope compositions of the exotic Ti from the measured composition, for different values of isotope fractionation in nature and for different mixing ratios of the exotic and normal components. The absolute Ti and Ca isotopic compositions still support the correlation of 50 Ti and 48 Ca effects in the FUN inclusions and imply contributions from neutron-rich equilibrium or quasi-equilibrium nucleosynthesis. The present identification of endemic effects at 46 Ti, for the absolute composition, implies a shortfall of an explosive-oxygen component or reflects significant isotope fractionation. Additional nucleosynthetic components are required by 47 Ti and 49 Ti effects. Components are also defined in which 48 Ti is enhanced. Results are given and discussed. (author)

  3. High Relative Abundance of Biofuel Sourced Ethanol in Precipitation in the US and Brazil Determined Using Compound Specific Stable Carbon Isotopes

    Science.gov (United States)

    Shimizu, M. S.; Felix, J. D. D.; Casas, M.; Avery, G. B., Jr.; Kieber, R. J.; Mead, R. N.; Willey, J. D.; Lane, C.

    2017-12-01

    Ethanol biofuel production and consumption have increased exponentially over the last two decades to help reduce greenhouse gas emissions. Currently, 85% of global ethanol production and consumption occurs in the US and Brazil. Increasing biofuel ethanol usage in these two countries enhances emissions of uncombusted ethanol to the atmosphere contributing to poor air quality. Although measurements of ethanol in the air and the precipitation reveal elevated ethanol concentrations in densely populated cities, other sources such as natural vegetation can contribute to emission to the atmosphere. Previous modeling studies indicated up to 12% of atmospheric ethanol is from anthropogenic emissions. Only one gas phase study in southern Florida attempted to constrain the two sources through direct isotopic measurements. The current study used a stable carbon isotope method to constrain sources of ethanol in rainwater from the US and Brazil. A method was developed using solid phase microextraction (SPME) with subsequent analysis by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Stable carbon isotope signatures (δ13C) of vehicle ethanol emission sources for both the US (-9.8‰) and Brazil (-12.7‰) represented C4 plants as feedstock (corn and sugarcane) for biofuel production. An isotope mixing model using biofuel from vehicles (C4 plants) and biogenic (C3 plants) end-members was implemented to estimate ethanol source apportionment in the rain. We found that stable carbon isotope ratio of ethanol in the rain ranged between -22.6‰ and -12.7‰. Our results suggest that the contribution of biofuel to atmospheric ethanol can be higher than previously estimated. As biofuel usage increasing globally, it is essential to determine the relative abundance of anthropogenic ethanol in other areas of the world.

  4. The relative isotopic abundance (δ13C, δ15N) during composting of agricultural wastes in relation to compost quality and feedstock.

    Science.gov (United States)

    Inácio, Caio T; Magalhães, Alberto M T; Souza, Paulo O; Chalk, Phillip M; Urquiaga, Segundo

    2018-05-01

    Variations in the relative isotopic abundance of C and N (δ 13 C and δ 15 N) were measured during the composting of different agricultural wastes using bench-scale bioreactors. Different mixtures of agricultural wastes (horse bedding manure + legume residues; dairy manure + jatropha mill cake; dairy manure + sugarcane residues; dairy manure alone) were used for aerobic-thermophilic composting. No significant differences were found between the δ 13 C values of the feedstock and the final compost, except for dairy manure + sugarcane residues (from initial ratio of -13.6 ± 0.2 ‰ to final ratio of -14.4 ± 0.2 ‰). δ 15 N values increased significantly in composts of horse bedding manure + legumes residues (from initial ratio of +5.9 ± 0.1 ‰ to final ratio of +8.2 ± 0.5 ‰) and dairy manure + jatropha mill cake (from initial ratio of +9.5 ± 0.2 ‰ to final ratio of +12.8 ± 0.7 ‰) and was related to the total N loss (mass balance). δ 13 C can be used to differentiate composts from different feedstock (e.g. C 3 or C 4 sources). The quantitative relationship between N loss and δ 15 N variation should be determined.

  5. Non-constant relative atomic masses due to varying isotopic abundance of polynuclidic elements and their effect on the accuracy of analytical results

    International Nuclear Information System (INIS)

    Gerstenberger, H.

    1981-01-01

    Alterations of actual relative atomic masses occur in natural samples by natural isotope ratio shifts of polynuclidic elements. Therefore, using nuclear properties for gaining a measuring signal, isotopic shifts of certain elements may lead to significant measuring errors

  6. Raman scattering method and apparatus for measuring isotope ratios and isotopic abundances

    International Nuclear Information System (INIS)

    Harney, R.C.; Bloom, S.D.

    1978-01-01

    Raman scattering is used to measure isotope ratios and/or isotopic abundances. A beam of quasi-monochromatic photons is directed onto the sample to be analyzed, and the resulting Raman-scattered photons are detected and counted for each isotopic species of interest. These photon counts are treated mathematically to yield the desired isotope ratios or isotopic abundances

  7. Isotopic abundance in atom trap trace analysis

    Science.gov (United States)

    Lu, Zheng-Tian; Hu, Shiu-Ming; Jiang, Wei; Mueller, Peter

    2014-03-18

    A method and system for detecting ratios and amounts of isotopes of noble gases. The method and system is constructed to be able to measure noble gas isotopes in water and ice, which helps reveal the geological age of the samples and understand their movements. The method and system uses a combination of a cooled discharge source, a beam collimator, a beam slower and magneto-optic trap with a laser to apply resonance frequency energy to the noble gas to be quenched and detected.

  8. LITERATURE SURVEY ON ISOTOPIC ABUNDANCE RATIO MEASUREMENTS - 2001-2005

    International Nuclear Information System (INIS)

    HOLDEN, N.E.

    2005-01-01

    Along with my usual weekly review of the published literature for new nuclear data, I also search for new candidates for best measurements of isotopic abundances from a single source. Most of the published articles, that I previously had found in the Research Library at the Brookhaven Lab, have already been sent to the members of the Atomic Weights Commission, by either Michael Berglund or Thomas Walczyk. In the last few days, I checked the published literature for any other articles in the areas of natural variations in isotopic abundance ratios, measurements of isotopic abundance ratios on samples of extra-terrestrial material and isotopic abundance ratio measurements performed using ICPMS instruments. Hopefully this information will be of interest to members of the Commission, the sub-committee on isotopic abundance measurements (SIAM), members of the former sub-committee on natural isotopic fractionation (SNIF), the sub-committee on extra-terrestrial isotope ratios (SETIR), the RTCE Task Group and the Guidelines Task Group, who are dealing with ICPMS and TIMS comparisons. In the following report, I categorize the publications in one of four areas. Measurements performed using either positive or negative ions with Thermal Ionization Mass Spectrometer, TIMS, instruments; measurements performed on Inductively Coupled Plasma Mass Spectrometer, ICPMS, instruments; measurements of natural variations of the isotopic abundance ratios; and finally measurements on extra-terrestrial samples with instrumentation of either type. There is overlap in these areas. I selected out variations and ET results first and then categorized the rest of the papers by TIMS and ICPMS

  9. Literature survey of isotopic abundance data for 1987-1989

    International Nuclear Information System (INIS)

    Holden, N.E.

    1989-01-01

    I have compiled all of the data on isotopic abundance measurements and their variation in nature for the time period since the last General Assembly. Most of the data deals with the variations in the abundances as given by per mil deviations from some standard. As such, they are not of major interest to the Atomic Weights Commission. However, there were some measurements which are of general interest in this list

  10. Isotopic Abundance and Chemical Purity Analysis of Stable Isotope Deuterium Labeled Sudan I

    Directory of Open Access Journals (Sweden)

    CAI Yin-ping;LEI Wen;ZHENG Bo;DU Xiao-ning

    2014-02-01

    Full Text Available It is important that to analysis of the isotopic abundance and chemical purity of Sudan I-D5, which is the internal standard of isotope dilution mass spectrometry. The isotopic abundance of Sudan I-D5 is detected by “mass cluster” classification method and LC-MS. The repeatability and reproducibility experiments were carried out by using different mass spectrometers and different operators. The RSD was less than 0.1%, so the repeatability and reproducibility were satisfactory. The accuracy and precision of the isotopic abundance analysis method was good with the results of F test and t test. The high performance liquid chromatography (HPLC had been used for detecting the chemical purity of Sudan I-D5 as external standard method.

  11. A Convenient Method for Estimation of the Isotopic Abundance in Uranium Bearing Samples

    International Nuclear Information System (INIS)

    AI -Saleh, F.S.; AI-Mukren, Alj.H.; Farouk, M.A.

    2008-01-01

    A convenient and simple method for estimation of the isotopic abundance in some uranium bearing samples using gamma-ray spectrometry is developed using a hyper pure germanium spectrometer and a standard uranium sample with known isotopic abundance

  12. Measurement of isotope abundance variations in nature by gravimetric spiking isotope dilution analysis (GS-IDA).

    Science.gov (United States)

    Chew, Gina; Walczyk, Thomas

    2013-04-02

    Subtle variations in the isotopic composition of elements carry unique information about physical and chemical processes in nature and are now exploited widely in diverse areas of research. Reliable measurement of natural isotope abundance variations is among the biggest challenges in inorganic mass spectrometry as they are highly sensitive to methodological bias. For decades, double spiking of the sample with a mix of two stable isotopes has been considered the reference technique for measuring such variations both by multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) and multicollector-thermal ionization mass spectrometry (MC-TIMS). However, this technique can only be applied to elements having at least four stable isotopes. Here we present a novel approach that requires measurement of three isotope signals only and which is more robust than the conventional double spiking technique. This became possible by gravimetric mixing of the sample with an isotopic spike in different proportions and by applying principles of isotope dilution for data analysis (GS-IDA). The potential and principle use of the technique is demonstrated for Mg in human urine using MC-TIMS for isotopic analysis. Mg is an element inaccessible to double spiking methods as it consists of three stable isotopes only and shows great potential for metabolically induced isotope effects waiting to be explored.

  13. Galilei-isotopic relativities

    International Nuclear Information System (INIS)

    Santilli, R.M.

    1991-09-01

    In this note we further develop the proposal made in preceding works of constructing the infinite family of Lie-isotopic liftings of Galilei's relativity for closed-isolated systems of particles possessing local, potential and selfadjoint, as well as nonlocal, nonhamiltonian and non selfadjoint internal forces. In particular, we show that the nonlinear and nonlocal generalization of the Galilei transformations introduced in a preceding note do indeed represent motion of extended particles within resistive media, but in such a way to coincide with the conventional transformations at the abstract, realization-free level. This allows the preservation of the basic, physical and mathematical axioms of Galilei's relativity under our liftings, and their realization in the most general possible nonlinear, nonlocal and nonhamiltonian way. (author). 18 refs, 1 fig

  14. Isotopic abundances relevant to the identification of magma sources

    International Nuclear Information System (INIS)

    O'Nions, R.K.

    1984-01-01

    The behaviour of natural radiogenic isotope tracers in the Earth that have lithophile and atmophile geochemical affinity is reviewed. The isotope tracer signature of oceanic and continental crust may in favourable circumstances by sufficiently distinct from that of the mantle to render a contribution from these sources resolvable within the isotopic composition of the magma. Components derived from the sedimentary and altered basaltic portion of oceanic crust are recognized in some island arc magmas from their Sr, Nd and Pb isotopic signatures. The rare-gas isotope tracers (He, Ar, Xe in particular) are not readily recycled into the mantle and thus provide the basis of an approach that is complementary to that based on the lithophile tracers. In particular, a small mantle-derived helium component may be readily recognized in the presence of a predominant radiogenic component generated in the continents. The importance of assessing the mass balance of these interactions rather than merely a qualitative recognition is emphasized. The question of the relative, contribution of continental-oceanic crust and mantle to magma sources is an essential part of the problem of generation and evolution of continental crust. An approach to this problem through consideration of the isotopic composition of sediments is briefly discussed. (author)

  15. Use of the natural abundance of stable isotopes in animal physiology

    International Nuclear Information System (INIS)

    Koyama, Takeo

    1987-01-01

    Recent studies on the natural abundance (δ-value) of stable isotopes in animals are reviewed. The δ 13 C value of livestock varies among different portions of the body and depending on living conditions, etc. Typically, however, it is about 1 percent larger than that of the feed used. The value of δ 15 N of the blood, milk and droppings is reported to be larger than that of the feed while that of urine is smaller with the decrease showing changes through the day. Natural δ 13 C and δ 15 N of animals are known to vary among the various organs and tissues. Investigations on cattle and two types musseks have shown that δ 13 C and δ 15 N have no significant relations with their age. The isotopic ratio of stable isotopes in animals is largely dependent on that of the feed used. Study results are cited on the changes in isotopic ratio of carbon and nitrogen along the digestion process of ruminants. Discussion is made on the causes for the changes in isotopic ratio during the metabolic process. Measurement of natural abundance of stable isotopes can be used as a tool for determining the eating habits of ungulate animals raised on grazing lands. (Nogami, K.)

  16. Potassium isotope abundances in Australasian tektites and microtektites.

    Science.gov (United States)

    Herzog, G. F.; O'D. Alexander, C. M.; Berger, E. L.; Delaney, J. S.; Glass, B. P.

    2008-10-01

    We report electron microprobe determinations of the elemental compositions of 11 Australasian layered tektites and 28 Australasian microtektites; and ion microprobe determinations of the 41K/39K ratios of all 11 tektites and 13 of the microtektites. The elemental compositions agree well with literature values, although the average potassium concentrations measured here for microtektites, 1.1 1.6 wt%, are lower than published average values, 1.9 2.9 wt%. The potassium isotope abundances of the Australasian layered tektites vary little. The average value of δ41K, 0.02 ± 0.12‰ (1σ mean), is indistinguishable from the terrestrial value (= 0 by definition) as represented by our standard, thereby confirming four earlier tektite analyses of Humayun and Koeberl (2004). In agreement with those authors, we conclude that evaporation has significantly altered neither the isotopic nor the elemental composition of Australasian layered tektites for elements less volatile than potassium. Although the average 41K/39K ratio of the microtektites, 1.1 ± 1.7‰ (1σ mean), is also statistically indistinguishable from the value for the standard, the individual ratios vary over a very large range, from -10.6 ± 1.4‰ to +13.8 ± 1.5‰ and at least three of them are significantly different from zero. We interpret these larger variations in terms of the evaporation of isotopically light potassium; condensation of potassium in the vapor plume; partial or complete stirring and quenching of the melts; and the possible uptake of potassium from seawater. That the average 41K/39K ratio of the microtektites equals the terrestrial value suggests that the microtektite-forming system was compositionally closed with respect to potassium and less volatile elements. The possibility remains open that 41K/39K ratios of microtektites vary systematically with location in the strewn field.

  17. Human baby hair amino acid natural abundance 15N-isotope values are not related to the 15N-isotope values of amino acids in mother's breast milk protein.

    Science.gov (United States)

    Romek, Katarzyna M; Julien, Maxime; Frasquet-Darrieux, Marine; Tea, Illa; Antheaume, Ingrid; Hankard, Régis; Robins, Richard J

    2013-12-01

    Since exclusively breast-suckled infants obtain their nutrient only from their mother's milk, it might be anticipated that a correlation will exist between the (15)N/(14)N isotope ratios of amino acids of protein of young infants and those supplied by their mother. The work presented here aimed to determine whether amino nitrogen transfer from human milk to infant hair protein synthesized within the first month of life conserves the maternal isotopic signature or whether post-ingestion fractionation dominates the nitrogen isotope spectrum. The study was conducted at 1 month post-birth on 100 mother-infant pairs. Isotope ratios (15)N/(14)N and (13)C/(12)C were measured using isotope ratio measurement by Mass Spectrometry (irm-MS) for whole maternal milk, and infant hair and (15)N/(14)N ratios were also measured by GC-irm-MS for the N-pivaloyl-O-isopropyl esters of amino acids obtained from the hydrolysis of milk and hair proteins. The δ(15)N and δ(13)C (‰) were found to be significantly higher in infant hair than in breast milk (δ(15)N, P amino acids in infant hair was also significantly higher than that in maternal milk (P < 0.001). By calculation, the observed shift in isotope ratio was shown not to be accounted for by the amino acid composition of hair and milk proteins, indicating that it is not simply due to differences in the composition in the proteins present. Rather, it would appear that each pool-mother and infant-turns over independently, and that fractionation in infant N-metabolism even in the first month of life dominates over the nutrient N-content.

  18. Determining the Local Abundance of Martian Methane and its 13-C/l2-C and D/H Isotopic Ratios for Comparison with Related Gas and Soil Analysis on the 2011 Mars Science Laboratory (MSL) Mission

    Science.gov (United States)

    Webster, Christopher R.; Mahaffy, Paul R.

    2011-01-01

    Understanding the origin of Martian methane will require numerous complementary measurements from both in situ and remote sensing investigations and laboratory work to correlate planetary surface geophysics with atmospheric dynamics and chemistry. Three instruments (Quadrupole Mass Spectrometer (QMS), Gas Chromatograph (GC) and Tunable Laser Spectrometer (TLS)) with sophisticated sample handling and processing capability make up the Sample Analysis at Mars (SAM) analytical chemistry suite on NASA s 2011 Mars Science Laboratory (MSL) Mission. Leveraging off the SAM sample and gas processing capability that includes methane enrichment, TLS has unprecedented sensitivity for measuring absolute methane (parts-per-trillion), water, and carbon dioxide abundances in both the Martian atmosphere and evolved from heated soil samples. In concert with a wide variety of associated trace gases (e.g. SO2, H2S, NH3, higher hydrocarbons, organics, etc.) and other isotope ratios measured by SAM, TLS will focus on determining the absolute abundances of methane, water and carbon dioxide, and their isotope ratios: 13C/12C and D/H in methane; 13C/12C and 18O/17O/16O in carbon dioxide; and 18O/17O/16O and D/H in water. Measurements near the MSL landing site will be correlated with satellite (Mars Express, Mars 2016) and ground-based observations.

  19. Variations in lead isotopic abundances in Sprague-Dawley rat tissues: possible reason of formation.

    Directory of Open Access Journals (Sweden)

    Duojian Liu

    Full Text Available It has been reported in previous research that the lead isotopic composition of blood, urine and feces samples statistically differed from the given lead sources in Sprague-Dawley (SD rats. However, the reason for this phenomenon is still unclear. An animal experiment was performed to investigate the lead isotope fractionation in diverse biological samples (i.e., lungs, liver, kidneys, bone and to explore the possible reasons. SD rats were intratracheally instilled with lead acetate at the concentrations of 0, 0.02, 0.2, and 2 mg/kg body weight. Biological samples were collected for lead isotope analysis using an inductively coupled plasma mass spectrometry (ICP-MS. Significant differences are observed in lead isotope abundances among the diverse biological samples. The lead isotope abundances ((206Pb, (207Pb and (208Pb in diverse biological samples show different degrees and directions of departure from the given lead source. The results suggest that differences in enrichment or depletion capacity for each lead isotope in the various tissues might lead to the variation in lead isotopic abundances in tissues. Moreover, a nonlinear relationship between the blood lead level and the lead isotope abundances in liver and bone is observed. When the whole-blood level is higher than 50 ng/mL, the lead isotopic compositions of biological samples tend to be the same. Thus, the data support the speculation of a fractionation functional threshold.

  20. Anatomy of a cluster IDP. Part 2: Noble gas abundances, trace element geochemistry, isotopic abundances, and trace organic chemistry of several fragments from L2008#5

    Science.gov (United States)

    Thomas, K. L.; Clemett, S. J.; Flynn, G. J.; Keller, L. P.; Mckay, David S.; Messenger, S.; Nier, A. O.; Schlutter, D. J.; Sutton, S. R.; Walker, R. M.

    1994-01-01

    The topics discussed include the following: noble gas content and release temperatures; trace element abundances; heating summary of cluster fragments; isotopic measurements; and trace organic chemistry.

  1. The depth distribution functions of the natural abundances of carbon isotopes in Alfisols thoroughly sampled by thin-layer sampling, and their relation to the dynamics of organic matter in theses soils

    International Nuclear Information System (INIS)

    Becker-Heidmann, P.

    1989-01-01

    The aim of this study was to gain fundamental statements on the relationship between the depth distributions of the natural abundances of 13 C and 14 C isotopes and the dynamics of the organic matter in Alfisols. For this purpose, six Alfisols were investigated: four forest soils from Northern Germany, two of them developed in Loess and two in glacial loam, one West German Loess soil used for fruit-growing and one agricultural granite-gneiss soil from the semiarid part of India. The soil was sampled as succesive horizontal layers of 2 cm depth from an area of 0.5 to 1 m 2 size, starting from the organic down to the C horizon or the lower part of the Bt. This kind of completely thin-layer-wise sampling was applied here for the first time. The carbon content and the natural abundances of the 13 C and the 14 C isotopes of each sample were determined. The δ 13 C value was measured by mass spectrometry. A vacuum preparation line with an electronically controlled cooling unit was constructed thereto. For the determination of the 14 C content, the sample carbon was transferred into benzene, and its activity was measured by liquid scintillation spectrometry. From the combination of the depth distribution functions of the 14 C activity and the δ 13 C value, and with the aid of additional analyses like C/N ratio and particle size distribution, a conclusive interpretation as to the dynamics of the organic matter in the investigated Alfisols is given. (orig./BBR)

  2. Ion Mobility Mass Spectrometry Direct Isotope Abundance Analysis

    International Nuclear Information System (INIS)

    Manard, Manuel J.; Weeks, Stephan; Kyle, Kevin

    2010-01-01

    The nuclear forensics community is currently engaged in the analysis of illicit nuclear or radioactive material for the purposes of non-proliferations and attribution. One technique commonly employed for gathering nuclear forensics information is isotope analysis. At present, the state-of-the-art methodology for obtaining isotopic distributions is thermal ionization mass spectrometry (TIMS). Although TIMS is highly accurate at determining isotope distributions, the technique requires an elementally pure sample to perform the measurement. The required radiochemical separations give rise to sample preparation times that can be in excess of one to two weeks. Clearly, the nuclear forensics community is in need of instrumentation and methods that can expedite their decision making process in the event of a radiological release or nuclear detonation. Accordingly, we are developing instrumentation that couples a high resolution IM drift cell to the front end of a MS. The IM cell provides a means of separating ions based upon their collision cross-section and mass-to-charge ratio (m/z). Two analytes with the same m/z, but with different collision cross-sections (shapes) would exit the cell at different times, essentially enabling the cell to function in a similar manner to a gas chromatography (GC) column. Thus, molecular and atomic isobaric interferences can be effectively removed from the ion beam. The mobility selected chemical species could then be introduced to a MS for high-resolution mass analysis to generate isotopic distributions of the target analytes. The outcome would be an IM/MS system capable of accurately measuring isotopic distributions while concurrently eliminating isobaric interferences and laboratory radiochemical sample preparation. The overall objective of this project is developing instrumentation and methods to produce near real-time isotope distributions with a modular mass spectrometric system that performs the required gas-phase chemistry and

  3. Carbon abundance and isotopic studies of Shergotty and other shergottite meteorites

    International Nuclear Information System (INIS)

    Wright, I.P.; Carr, R.H.; Pillinger, C.T.

    1986-01-01

    Consortium samples of the Shergotty meteorite have been measured for C abundance and isotopic composition by stepped combustion and the results compared to different samples of the same meteorite and the other known shergottites. Clearly, the shergottite meteorites have a complex C chemistry and contain components of both low and high thermal stability. Two components labile at low temperature can be tentatively identified, one which is enriched in 13 C and may be related to the carbonate thought to be produced by pre-terrestrial weathering in Nakhla. The other, which is isotopically light, is presently of unknown origin but we speculate that it may be related to shock effects. At high temperatures, two of the samples examined show evidence for a component of CO 2 trapped from the martian atmosphere, possibly indicating that shock-produced glass is heterogeneously distributed throughout the shergottite group. This interpretation is corroborated by N isotope measurements made on one of the specimens. All samples appear to contain evidence of a high temperature magmatic component of C. (author)

  4. The evolution of the global selenium cycle: Secular trends in Se isotopes and abundances

    Science.gov (United States)

    Stüeken, E. E.; Buick, R.; Bekker, A.; Catling, D.; Foriel, J.; Guy, B. M.; Kah, L. C.; Machel, H. G.; Montañez, I. P.; Poulton, S. W.

    2015-08-01

    The Earth's surface has undergone major transitions in its redox state over the past three billion years, which have affected the mobility and distribution of many elements. Here we use Se isotopic and abundance measurements of marine and non-marine mudrocks to reconstruct the evolution of the biogeochemical Se cycle from ∼3.2 Gyr onwards. The six stable isotopes of Se are predominantly fractionated during redox reactions under suboxic conditions, which makes Se a potentially valuable new tool for identifying intermediate stages from an anoxic to a fully oxygenated world. δ82/78Se shows small fractionations of mostly less than 2‰ throughout Earth's history and all are mass-dependent within error. In the Archean, especially after 2.7 Gyr, we find an isotopic enrichment in marine (+0.37 ± 0.27‰) relative to non-marine samples (-0.28 ± 0.67‰), paired with increasing Se abundances. Student t-tests show that these trends are statistically significant. Although we cannot completely rule out the possibility of volcanic Se addition, these trends may indicate the onset of oxidative weathering on land, followed by non-quantitative reduction of Se oxyanions during fluvial transport. The Paleoproterozoic Great Oxidation Event (GOE) is not reflected in the marine δ82/78Se record. However, we find a major inflection in the secular δ82/78Se trend during the Neoproterozoic, from a Precambrian mean of +0.42 ± 0.45‰ to a Phanerozoic mean of -0.19 ± 0.59‰. This drop probably reflects the oxygenation of the deep ocean at this time, stabilizing Se oxyanions throughout the water column. Since then, reduction of Se oxyanions has likely been restricted to anoxic basins and diagenetic environments in sediments. In light of recent Cr isotope data, it is likely that oxidative weathering before the Neoproterozoic produced Se oxyanions in the intermediate redox state SeIV, whereas the fully oxidized species SeVI became more abundant after the Neoproterozoic rise of

  5. ICP-oa TOFMS utilisation to determine the Gd isotopic abundance in gadolinium nitrate

    International Nuclear Information System (INIS)

    Dragomir, M.; Ohai, D.; Dumitrescu, I.; Furtuna, I.

    2010-01-01

    This paper is describes the development of a method that should permit the determination of isotope abundance of gadolinium in gadolinium nitrate, used as burnable poison at Cernavoda NPP. To determine the isotopic abundance of gadolinium the inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometer (ICP-oa TOFMS) was used. The ICP-oa TOFMS allows the elimination of noise associated with instrumental drift and instability (flicker noise). The absence of flicker noise in the ICP-oa TOFMS means that the isotope ratios can be measured up to the statistical limit of ion counting. With TOFMS, each spectrum acquired represents signals from ions extracted from the plasma during the same time interval, formed from identical plasma and sample introduction events. Therefore, the ICP-oa TOFMS, Optimass 8000, has been successfully used for isotope ratio measurements of Gd in gadolinium nitrate [Gd (NO 3 ) 3 x 6H 2 O] sample solutions. (authors)

  6. Isotope-abundance variations and atomic weights of selected elements: 2016 (IUPAC Technical Report)

    Science.gov (United States)

    Coplen, Tyler B.; Shrestha, Yesha

    2016-01-01

    There are 63 chemical elements that have two or more isotopes that are used to determine their standard atomic weights. The isotopic abundances and atomic weights of these elements can vary in normal materials due to physical and chemical fractionation processes (not due to radioactive decay). These variations are well known for 12 elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, magnesium, silicon, sulfur, chlorine, bromine, and thallium), and the standard atomic weight of each of these elements is given by IUPAC as an interval with lower and upper bounds. Graphical plots of selected materials and compounds of each of these elements have been published previously. Herein and at the URL http://dx.doi.org/10.5066/F7GF0RN2, we provide isotopic abundances, isotope-delta values, and atomic weights for each of the upper and lower bounds of these materials and compounds.

  7. On krypton isotopic abundances in the sun and in the solar wind

    Science.gov (United States)

    Marti, K.

    1980-01-01

    The Kr isotopic systematics in the meteorite Pesyanoe which is known to contain solar-type gases, are reported. Discrepancies in the isotopic data of fractions released at stepwise increasing temperatures cannot be reconciled with spallation Kr components, although spallation effects are significant. Fractionation mechanisms on the parent body and in the solar wind source region are considered and the implications for solar abundances discussed.

  8. Characterizing uranium oxide reference particles for isotopic abundances and uranium mass by single particle isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Kraiem, M.; Richter, S.; Erdmann, N.; Kühn, H.; Hedberg, M.; Aregbe, Y.

    2012-01-01

    Highlights: ► A method to quantify the U mass in single micron particles by ID-TIMS was developed. ► Well-characterized monodisperse U-oxide particles produced by an aerosol generator were used. ► A linear correlation between the mass of U and the volume of particle(s) was found. ► The method developed is suitable for determining the amount of U in a particulate reference material. - Abstract: Uranium and plutonium particulate test materials are becoming increasingly important as the reliability of measurement results has to be demonstrated to regulatory bodies responsible for maintaining effective nuclear safeguards. In order to address this issue, the Institute for Reference Materials and Measurements (IRMM) in collaboration with the Institute for Transuranium Elements (ITU) has initiated a study to investigate the feasibility of preparing and characterizing a uranium particle reference material for nuclear safeguards, which is finally certified for isotopic abundances and for the uranium mass per particle. Such control particles are specifically required to evaluate responses of instruments based on mass spectrometric detection (e.g. SIMS, TIMS, LA-ICPMS) and to help ensuring the reliability and comparability of measurement results worldwide. In this paper, a methodology is described which allows quantifying the uranium mass in single micron particles by isotope dilution thermal ionization mass spectrometry (ID-TIMS). This methodology is characterized by substantial improvements recently achieved at IRMM in terms of sensitivity and measurement accuracy in the field of uranium particle analysis by TIMS. The use of monodisperse uranium oxide particles prepared using an aerosol generation technique developed at ITU, which is capable of producing particles of well-characterized size and isotopic composition was exploited. The evidence of a straightforward correlation between the particle volume and the mass of uranium was demonstrated in this study

  9. Element distribution and noble gas isotopic abundances in lunar meteorite Allan Hills A81005

    International Nuclear Information System (INIS)

    Kraehenbuehl, U.; Eugster, O.; Niedermann, S.

    1986-01-01

    Antarctic meteorite ALLAN HILLS A81005, an anorthositic breccia, is recognized to be of lunar origin. The noble gases in this meteorite were analyzed and found to be solar-wind implanted gases, whose absolute and relative concentrations are quite similar to those in lunar regolith samples. A sample of this meteorite was obtained for the analysis of the noble gas isotopes, including Kr(81), and for the determination of the elemental abundances. In order to better determine the volume derived from the surface correlated gases, grain size fractions were prepared. The results of the instrumental measurements of the gamma radiation are listed. From the amounts of cosmic ray produced noble gases and respective production rates, the lunar surface residence times were calculated. It was concluded that the lunar surface time is about half a billion years

  10. Pu abundances, concentrations, and isotopics by x- and gamma-ray spectrometry assay techniques

    International Nuclear Information System (INIS)

    Camp, D.C.; Gunnink, R.; Ruhter, W.D.; Prindle, A.L.; Gomes, R.J.

    1986-01-01

    Two x- and gamma-ray systems were recently installed at-line in gloveboxes and will measure Pu solution concentrations from 5 to 105 g/L. These NDA technique, developed and refined over the past decade, are now used domestically and internationally for nuclear material process monitoring and accountability needs. In off- and at-line installations, they can measure solution concentrations to 0.2%. The K-XRFA systems use a transmission source to correct for solution density. The gamma-ray systems use peaks from 59- to 208-keV to determine solution concentrations and relative isotopics. A Pu check source monitors system stability. These two NDA techniques can be combined to form a new, NDA measurement methodology. With the instrument located outside of a glovebox, both relative Pu isotopics and absolute Pu abundances of a sample located inside a glovebox can be measured. The new technique works with either single or dual source excitation; the former for a detector 6 to 20 cm away with no geometric corrections needed; the latter requires geometric corrections or source movement if the sample cannot be measured at the calibration distance. 4 refs., 7 figs., 2 tabs

  11. Relative Abundance of Adult Mosquitoes in University of Abuja Main ...

    African Journals Online (AJOL)

    Relative Abundance of Adult Mosquitoes in University of Abuja Main ... relative abundance of adult mosquitoes in four selected sites in University of Abuja ... These results indicated that vectors of mosquito-borne diseases are breeding in the ...

  12. ANALYSIS OF RICIN TOXIN PREPARATIONS FOR CARBOHYDRATE AND FATTY ACID ABUNDANCE AND ISOTOPE RATIO INFORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Wunschel, David S.; Kreuzer-Martin, Helen W.; Antolick, Kathryn C.; Colburn, Heather A.; Moran, James J.; Melville, Angela M.

    2009-12-01

    This report describes method development and preliminary evaluation for analyzing castor samples for signatures of purifying ricin. Ricin purification from the source castor seeds is essentially a problem of protein purification using common biochemical methods. Indications of protein purification will likely manifest themselves as removal of the non-protein fractions of the seed. Two major, non-protein, types of biochemical constituents in the seed are the castor oil and various carbohydrates. The oil comprises roughly half the seed weight while the carbohydrate component comprises roughly half of the remaining “mash” left after oil and hull removal. Different castor oil and carbohydrate components can serve as indicators of specific toxin processing steps. Ricinoleic acid is a relatively unique fatty acid in nature and is the most abundant component of castor oil. The loss of ricinoleic acid indicates a step to remove oil from the seeds. The relative amounts of carbohydrates and carbohydrate-like compounds, including arabinose, xylose, myo-inositol fucose, rhamnose, glucosamine and mannose detected in the sample can also indicate specific processing steps. For instance, the differential loss of arabinose relative to mannose and N-acetyl glucosamine indicates enrichment for the protein fraction of the seed using protein precipitation. The methods developed in this project center on fatty acid and carbohydrate extraction from castor samples followed by derivatization to permit analysis by gas chromatography-mass spectrometry (GC-MS). Method descriptions herein include: the source and preparation of castor materials used for method evaluation, the equipment and description of procedure required for chemical derivatization, and the instrument parameters used in the analysis. Two types of derivatization methods describe analysis of carbohydrates and one procedure for analysis of fatty acids. Two types of GC-MS analysis is included in the method development, one

  13. Abundances of light isotopes in galactic cosmic rays and the interstellar gas density

    International Nuclear Information System (INIS)

    Westergaard, N.J.

    1979-01-01

    The fluxes of the light isotopes in the galactic cosmic rays are calculated in the energy range from 10 MeV to 5 GeV. The mean amount of matter traversed is taken to increase with decreasing energy, and various forms of the source spectrum are assumed. It is shown that it is possible to reconcile all observed abundance ratios including the low 10 Be abundance found by Garcia-Munoz et al. with an interstellar gas density of 1 atom cm -1 . However, a low value for the adiabatic deceleration in the solor cavity must be assumed. Comparing isotopes of the light elements does not give a unique solution for the deceleration, and it seems to be more profitable to use the isotopes of H and He for this purpose

  14. Improve accuracy and sensibility in glycan structure prediction by matching glycan isotope abundance

    International Nuclear Information System (INIS)

    Xu Guang; Liu Xin; Liu Qingyan; Zhou Yanhong; Li Jianjun

    2012-01-01

    Highlights: ► A glycan isotope pattern recognition strategy for glycomics. ► A new data preprocessing procedure to detect ion peaks in a giving MS spectrum. ► A linear soft margin SVM classification for isotope pattern recognition. - Abstract: Mass Spectrometry (MS) is a powerful technique for the determination of glycan structures and is capable of providing qualitative and quantitative information. Recent development in computational method offers an opportunity to use glycan structure databases and de novo algorithms for extracting valuable information from MS or MS/MS data. However, detecting low-intensity peaks that are buried in noisy data sets is still a challenge and an algorithm for accurate prediction and annotation of glycan structures from MS data is highly desirable. The present study describes a novel algorithm for glycan structure prediction by matching glycan isotope abundance (mGIA), which takes isotope masses, abundances, and spacing into account. We constructed a comprehensive database containing 808 glycan compositions and their corresponding isotope abundance. Unlike most previously reported methods, not only did we take into count the m/z values of the peaks but also their corresponding logarithmic Euclidean distance of the calculated and detected isotope vectors. Evaluation against a linear classifier, obtained by training mGIA algorithm with datasets of three different human tissue samples from Consortium for Functional Glycomics (CFG) in association with Support Vector Machine (SVM), was proposed to improve the accuracy of automatic glycan structure annotation. In addition, an effective data preprocessing procedure, including baseline subtraction, smoothing, peak centroiding and composition matching for extracting correct isotope profiles from MS data was incorporated. The algorithm was validated by analyzing the mouse kidney MS data from CFG, resulting in the identification of 6 more glycan compositions than the previous annotation

  15. On the enrichment of low-abundant isotopes of light chemical elements by gas centrifuges

    International Nuclear Information System (INIS)

    Borisevich, V.D.; Morozov, O.E.; Zaozerskiy, Yu.P.; Shmelev, G.M.; Shipilov, Yu.D.

    2000-01-01

    A brief review of the main areas for the application of the isotopes 15 N and 13 C is made. Separation of the nitrogen isotopes in a single gas centrifuge in the form of pure nitrogen, ammonia, and trifluoride of nitrogen as well as the carbon isotopes in the form of carbon dioxide has been studied by means of numerical simulation. The parameters of the centrifugal machine investigated were close to the parameters of the Iguassu machine. The dependence of the efficiency criterion versus the basic parameters of the separation process has been explored in the computational experiments. Comparisons of the calculated results with the experimental data have shown good agreement. The results obtained have demonstrated the possibility of using gas centrifuge technology to enrich successfully the low-abundant isotopes of light chemical elements

  16. Metallicity-Dependent Isotopic Abundances and the Impact of Helium Rate Uncertainties in Massive Stars

    Science.gov (United States)

    West, Christopher

    2013-03-01

    All stellar evolution models for nucleosynthesis require an initial isotopic abundance set to use as a starting point, because nuclear reactions occur between isotopes. Generally, our knowledge of isotopic abundances of stars is fairly incomplete except for the Solar System. We develop a first model for a complete average isotopic decomposition as a function of metallicity. Our model is based on the underlying nuclear astrophysics processes, and is fitted to observational data, rather than traditional forward galactic chemical evolution modeling which integrates stellar yields beginning from big bang nucleosynthesis. We first decompose the isotopic solar abundance pattern into contributions from astrophysical sources. Each contribution is then assumed to scale as a function of metallicity. The resulting total isotopic abundances are summed into elemental abundances and fitted to available halo and disk stellar data to constrain the model's free parameter values. This procedure allows us to use available elemental observational data to reconstruct and constrain both the much needed complete isotopic evolution that is not accessible to current observations, and the underlying astrophysical processes. Our model finds a best fit for Type Ia supernovae contributing ˜0.7 to the solar Fe abundance, and Type Ia onset occurring at [Fe/H]~1.2, in agreement with typical values. The completed model can be used in future nucleosynthesis studies. We also perform a preliminary analysis to assess the impact of our isotopic scaling model on the resulting nucleosynthesis of massive stars, compared to a linear interpolation method. Using these two input methods we compute a limited grid of stellar models, and compare the final nucleosynthesis to observations. The compactness parameter was first used to assess which models would likely explode as successful supernovae, and contribute explosive nucleosynthesis yields. We find a better agreement to solar observations using the scaling

  17. Electrolytic recovery of mercury enriched in isotopic abundance

    Science.gov (United States)

    Grossman, Mark W.

    1991-01-01

    The present invention is directed to a method of electrolytically extracting liquid mercury from HgO or Hg.sub.2 Cl.sub.2. Additionally there are disclosed two related techniques associated with the present invention, namely (1) a technique for selectively removing product from different regions of a long photochemical reactor (photoreactor) and (2) a method of accurately measuring the total quantity of mercury formed as either HgO or Hg.sub.2 Cl.sub.2.

  18. Ar-39 Detection at the 10^-16 Isotopic Abundance Level with Atom Trap Trace Analysis

    OpenAIRE

    Jiang, W.; Williams, W. D.; Bailey, K.; Davis, A. M.; Hu, S. -M.; Lu, Z. -T.; O'Connor, T. P.; Purtschert, R.; Sturchio, N. C.; Sun, Y. R.; Mueller, P.

    2011-01-01

    Atom Trap Trace Analysis (ATTA), a laser-based atom counting method, has been applied to analyze atmospheric Ar-39 (half-life = 269 yr), a cosmogenic isotope with an isotopic abundance of 8x10^-16. In addition to the superior selectivity demonstrated in this work, counting rate and efficiency of ATTA have been improved by two orders of magnitude over prior results. Significant applications of this new analytical capability lie in radioisotope dating of ice and water samples and in the develop...

  19. Ar39 Detection at the 10-16 Isotopic Abundance Level with Atom Trap Trace Analysis

    Science.gov (United States)

    Jiang, W.; Williams, W.; Bailey, K.; Davis, A. M.; Hu, S.-M.; Lu, Z.-T.; O'Connor, T. P.; Purtschert, R.; Sturchio, N. C.; Sun, Y. R.; Mueller, P.

    2011-03-01

    Atom trap trace analysis, a laser-based atom counting method, has been applied to analyze atmospheric Ar39 (half-life=269yr), a cosmogenic isotope with an isotopic abundance of 8×10-16. In addition to the superior selectivity demonstrated in this work, the counting rate and efficiency of atom trap trace analysis have been improved by 2 orders of magnitude over prior results. The significant applications of this new analytical capability lie in radioisotope dating of ice and water samples and in the development of dark matter detectors.

  20. The Oxygen Isotopic Composition of MIL 090001: A CR2 Chondrite with Abundant Refractory Inclusions

    Science.gov (United States)

    Keller, Lindsay P.; McKeegan, K. D.; Sharp, Z. D.

    2012-01-01

    MIL 090001 is a large (>6 kg) carbonaceous chondrite that was classified as a member of the CV reduced subgroup (CVred) that was recovered during the 2009-2010 ANSMET field season [1]. Based on the abundance of refractory inclusions and the extent of aqueous alteration, Keller [2] suggested a CV2 classification. Here we report additional mineralogical and petrographic data for MIL 090001, its whole-rock oxygen isotopic composition and ion microprobe analyses of individual phases. The whole rock oxygen isotopic analyses show that MIL 090001 should be classified as a CR chondrite.

  1. Application of mass-predictions to isotope-abundances in breeder-reactor cores

    CERN Document Server

    Kirchner, G

    1981-01-01

    The decay-heat and isotope composition of breeder reactor-cores is calculated at normal shut-down, and a core disintegration event. Using the ORIGEN-code, the influence of the most neutron-rich fission-yield nuclei is studied. Their abundances depend on the assumption about the nuclear data (mass and half-lives). The total decay-heat is not changed from any technical viewpoint. (15 refs).

  2. Oxygen isotopic abundances in the atmospheres of seven red giant stars

    International Nuclear Information System (INIS)

    Harris, M.J.; Lambert, D.L.

    1984-01-01

    Abundances ratios of the oxygen isotopes have been measured in α Tau, β And, μ Gem, α Her, β Peg, γ Dra, and α Boo. In all the stars the 16 O/ 18 O ratios are similar; the mean value is 475, which is consistent with the solar system value 16 O/ 18 O = 490. The 16 O/ 17 O ratios range from approx.1000 for β Peg and α Boo to 16 O/ 17 O = 160 for β And

  3. Lithium isotopic abundances in metal-poor stars: a problem for standard big bang nucleosynthesis?

    International Nuclear Information System (INIS)

    Nissen, P.E.; Asplund, M.; Lambert, D.L.; Primas, F.; Smith, V.V.

    2005-01-01

    Spectral obtained with VLT/UVES suggest the existence of the 6 Li isotope in several metal-poor stars at a level that challenges ideas about its synthesis. The 7 Li abundance is, on the other hand, a factor of three lower than predicted by standard Big Bang nucleosynthesis theory. Both problems may be explained if decaying suppersymmetric particles affect the synthesis of light elements in the Big Bang. (orig.)

  4. Mercury (Hg) in meteorites: Variations in abundance, thermal release profile, mass-dependent and mass-independent isotopic fractionation

    Science.gov (United States)

    Meier, Matthias M. M.; Cloquet, Christophe; Marty, Bernard

    2016-06-01

    We have measured the concentration, isotopic composition and thermal release profiles of Mercury (Hg) in a suite of meteorites, including both chondrites and achondrites. We find large variations in Hg concentration between different meteorites (ca. 10 ppb to 14,000 ppb), with the highest concentration orders of magnitude above the expected bulk solar system silicates value. From the presence of several different Hg carrier phases in thermal release profiles (150-650 °C), we argue that these variations are unlikely to be mainly due to terrestrial contamination. The Hg abundance of meteorites shows no correlation with petrographic type, or mass-dependent fractionation of Hg isotopes. Most carbonaceous chondrites show mass-independent enrichments in the odd-numbered isotopes 199Hg and 201Hg. We show that the enrichments are not nucleosynthetic, as we do not find corresponding nucleosynthetic deficits of 196Hg. Instead, they can partially be explained by Hg evaporation and redeposition during heating of asteroids from primordial radionuclides and late-stage impact heating. Non-carbonaceous chondrites, most achondrites and the Earth do not show these enrichments in vapor-phase Hg. All meteorites studied here have however isotopically light Hg (δ202Hg = ∼-7 to -1) relative to the Earth's average crustal values, which could suggest that the Earth has lost a significant fraction of its primordial Hg. However, the late accretion of carbonaceous chondritic material on the order of ∼2%, which has been suggested to account for the water, carbon, nitrogen and noble gas inventories of the Earth, can also contribute most or all of the Earth's current Hg budget. In this case, the isotopically heavy Hg of the Earth's crust would have to be the result of isotopic fractionation between surface and deep-Earth reservoirs.

  5. Axion: Mass -- Dark Matter Abundance Relation

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The axion is a hypothetical particle which would explain why QCD is approximately T-conserving, and is also an excellent Cold Dark Matter candidate. It should be possible to make a clean theoretical prediction relating the dark matter density in axions and the axion mass (under reasonable assumptions about inflation). But the axion's early-Universe dynamics, which establish its density as dark matter, are unexpectedly rich in a way which is only starting to yield to quantitative numerical study.

  6. The determination of minor isotope abundances in naturally occurring uranium materials. The tracing power of isotopic signatures for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Ovaskainen, R

    1999-11-01

    The mass spectrometric determination of minor abundant isotopes, {sup 234}U and {sup 236}U in naturally occurring uranium materials requires instruments of high abundance sensitivity and the use of highly sensitive detection systems. In this study the thermal ionisation mass spectrometer Finnigan MAT 262RPQ was used. It was equipped with 6 Faraday cups and a Secondary Electron Multiplier (SEM), which was operated in pulse counting mode for the detection of extremely low ion currents. The dynamic measurement range was increased considerably combining these two different detectors. The instrument calibration was performed carefully. The linearity of each detector, the deadtime of the ion counting detector, the detector normalisation factor, the baseline of each detector and the mass discrimination in the ion source were checked and optimised. A measurement technique based on the combination of a Gas Source Mass Spectrometry (GSMS) and a Thermal Ionisation Mass Spectrometry (TIMS) was developed for the accurate determination of isotopic composition in naturally occurring uranium materials. Because the expected ratio of n({sup 234}U)/n({sup 238}U) exceeded the dynamic measurement range of the Faraday detectors of the TIMS instrument, an experimental design using a combination of two detectors was developed. The n({sup 234}U)/n({sup 235}U) and n({sup 236}U)/n({sup 235}U) ratios were determined using ion counting in combination with the decelerating device. The n({sup 235}U)/n({sup 238}U) ratio was determined by the Faraday detector. This experimental design allowed the detector cross calibration to be circumvented. Precisions of less than 1 percent for the n({sup 234}U)/n({sup 235}U) ratios and 5-25 percent for the n({sup 236}U)/n({sup 235}U) ratios were achieved. The purpose of the study was to establish a register of isotopic signatures for natural uranium materials. The amount ratio, and isotopic composition of 18 ore concentrates, collected by the International

  7. The determination of minor isotope abundances in naturally occurring uranium materials. The tracing power of isotopic signatures for uranium

    International Nuclear Information System (INIS)

    Ovaskainen, R.

    1999-01-01

    The mass spectrometric determination of minor abundant isotopes, 234 U and 236 U in naturally occurring uranium materials requires instruments of high abundance sensitivity and the use of highly sensitive detection systems. In this study the thermal ionisation mass spectrometer Finnigan MAT 262RPQ was used. It was equipped with 6 Faraday cups and a Secondary Electron Multiplier (SEM), which was operated in pulse counting mode for the detection of extremely low ion currents. The dynamic measurement range was increased considerably combining these two different detectors. The instrument calibration was performed carefully. The linearity of each detector, the deadtime of the ion counting detector, the detector normalisation factor, the baseline of each detector and the mass discrimination in the ion source were checked and optimised. A measurement technique based on the combination of a Gas Source Mass Spectrometry (GSMS) and a Thermal Ionisation Mass Spectrometry (TIMS) was developed for the accurate determination of isotopic composition in naturally occurring uranium materials. Because the expected ratio of n( 234 U)/n( 238 U) exceeded the dynamic measurement range of the Faraday detectors of the TIMS instrument, an experimental design using a combination of two detectors was developed. The n( 234 U)/n( 235 U) and n( 236 U)/n( 235 U) ratios were determined using ion counting in combination with the decelerating device. The n( 235 U)/n( 238 U) ratio was determined by the Faraday detector. This experimental design allowed the detector cross calibration to be circumvented. Precisions of less than 1 percent for the n( 234 U)/n( 235 U) ratios and 5-25 percent for the n( 236 U)/n( 235 U) ratios were achieved. The purpose of the study was to establish a register of isotopic signatures for natural uranium materials. The amount ratio, and isotopic composition of 18 ore concentrates, collected by the International Atomic Energy Agency (IAEA) from uranium milling and mining

  8. Influence of Biofield Energy Treatment on Isotopic Abundance Ratio in Aniline Derivatives

    OpenAIRE

    Nayak, Gopal; Trivedi, Mahendra Kumar; Trivedi, Dahryn; Branton, Alice

    2015-01-01

    The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of 13C/12C or 2H/1H or 15N/14N ≡ (PM+1)/PM in aniline; and (PM+1)/PM and 81Br/79Br ≡ (PM+2)/PM in 4-bromoaniline using Gas Chromatography-Mass Spectrometry (GC-MS). Aniline and 4-bromoaniline samples were divided into two parts: control and treated. The control part remained as untreated, while the treated part was subjected to Mr. Trivedi’s biofield energy treatment. The treated samples we...

  9. Influence of Biofield Energy Treatment on Isotopic Abundance Ratio in Aniline Derivatives

    OpenAIRE

    Trivedi , Mahendra Kumar; Branton , Alice; Trivedi , Dahryn; Nayak , Gopal; Saikia , Gunin; Jana , Snehasis

    2015-01-01

    International audience; The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of 13C/12C or 2H/1H or 15N/14N ≡ (PM+1)/PM in aniline; and (PM+1)/PM and 81Br/79Br ≡ (PM+2)/PM in 4-bromoaniline using Gas Chromatography-Mass Spectrometry (GC-MS). Aniline and 4-bromoaniline samples were divided into two parts: control and treated. The control part remained as untreated, while the treated part was subjected to Mr. Trivedi’s biofield energy treatment...

  10. The use of lead isotopic abundances in trace uranium samples for nuclear forensics analysis

    International Nuclear Information System (INIS)

    Fahey, A.J.; Ritchie, N.W.M.; Newbury, D.E.; Small, J.A.

    2010-01-01

    Secondary ion mass spectrometry (SIMS), secondary electron microscopy (SEM) and X-ray analysis have been applied to the measurement of U-bearing particles with the intent of gleaning information concerning their history and/or origin. The lead isotopic abundances are definitive indicators that U-bearing particles have come from an ore-body, even if they have undergone chemical processing. SEM images and X-ray analysis can add further information to the study that may allude to the extent of chemical processing. The presence of 'common' lead that does not exhibit a radiogenic signature is clear evidence of anthropogenic origin. (author)

  11. Influence of Biofield Energy Treatment on Isotopic Abundance Ratio in Aniline Derivatives

    OpenAIRE

    Mahendra, Trivedi; Alice, Branton; Dahryn, Trivedi; Gopal, Nayak

    2015-01-01

    The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of 13C/12C or 2H/1H or 15N/14N ≡ (PM+1)/PM in aniline; and (PM+1)/PM and 81Br/79Br ≡ (PM+2)/PM in 4-bromoaniline using Gas Chromatography-Mass Spectrometry (GC-MS). Aniline and 4-bromoaniline samples were divided into two parts: control and treated. The control part remained as untreated, while the treated part was subjected to Mr. Trivedi's biofield energy treatment. The treated samples we...

  12. types and abundance of arthropod fauna in relation to physico ...

    African Journals Online (AJOL)

    DJFLEX

    TYPES AND ABUNDANCE OF ARTHROPOD FAUNA IN RELATION ... The occurrence of arthropods associated with the bottom sediment of Warri River was investigated, and samples were collected ..... to analysis of the vegetation on Danish.

  13. Sims Analysis of Water Abundance and Hydrogen Isotope in Lunar Highland Plagioclase

    Science.gov (United States)

    Hui, Hejiu; Guan, Yunbin; Chen, Yang; Peslier, Anne H.; Zhang, Youxue; Liu, Yang; Rossman, George R.; Eiler, John M.; Neal, Clive R.

    2015-01-01

    The detection of indigenous water in mare basaltic glass beads has challenged the view established since the Apollo era of a "dry" Moon. Since this discovery, measurements of water in lunar apatite, olivine-hosted melt inclusions, agglutinates, and nominally anhydrous minerals have confirmed that lunar igneous materials contain water, implying that some parts of lunar mantle may have as much water as Earth's upper mantle. The interpretation of hydrogen (H) isotopes in lunar samples, however, is controversial. The large variation of H isotope ratios in lunar apatite (delta Deuterium = -202 to +1010 per mille) has been taken as evidence that water in the lunar interior comes from the lunar mantle, solar wind protons, and/or comets. The very low deuterium/H ratios in lunar agglutinates indicate that solar wind protons have contributed to their hydrogen content. Conversely, H isotopes in lunar volcanic glass beads and olivine-hosted melt inclusions being similar to those of common terrestrial igneous rocks, suggest a common origin for water in both Earth and Moon. Lunar water could be inherited from carbonaceous chondrites, consistent with the model of late accretion of chondrite-type materials to the Moon as proposed by. One complication about the sources of lunar water, is that geologic processes (e.g., late accretion and magmatic degassing) may have modified the H isotope signatures of lunar materials. Recent FTIR analyses have shown that plagioclases in lunar ferroan anorthosite contain approximately 6 ppm H2O. So far, ferroan anorthosite is the only available lithology that is believed to be a primary product of the lunar magma ocean (LMO). A possible consequence is that the LMO could have contained up to approximately 320 ppm H2O. Here we examine the possible sources of water in the LMO through measurements of water abundances and H isotopes in plagioclase of two ferroan anorthosites and one troctolite from lunar highlands.

  14. Process chemistry related to hydrogen isotopes

    International Nuclear Information System (INIS)

    Iwasaki, Matae; Ogata, Yukio

    1991-01-01

    Hydrogen isotopes, that is, protium, deuterium and tritium, are all related deeply to energy in engineering region. Deuterium and tritium exist usually as water in extremely thin state. Accordingly, the improvement of the technology for separating these isotopes is a large engineering subject. Further, tritium is radioactive and its half-life period is 12.26 years, therefore, it is desirable to fix it in more stable form besides its confinement in the handling system. As the chemical forms of hydrogen, the molecular hydrogen with highest reactivity, metal hydride, carbon-hydrogen-halogen system compounds, various inorganic hydrides, most stable water and hydroxides are enumerated. The grasping of the behavior from reaction to stable state of these hydrogen compounds and the related materials is the base of process chemistry. The reaction of exchanging isotopes between water and hydrogen on solid catalyzers, the decomposition of ethane halide containing hydrogen, the behavior of water and hydroxides in silicates are reported. The isotope exchange between water and hydrogen is expected to be developed as the process of separating and concentrating hydrogen isotopes. (K.I.) 103 refs

  15. Relative abundance of desert tortoises on the Nevada Test Site

    International Nuclear Information System (INIS)

    Rautenstrauch, K.R.; O'Farrell, T.P.

    1993-01-01

    Seven hundred fifty-nine transects having a total length of 1,191 km were walked during 1981--1986 to determine the distribution and relative abundance of desert tortoises (Gopherus agassizii) on the Nevada Test Site (NTS). The abundance of tortoises on NTS was low to very low relative to other populations in the Mojave Desert. Sign of tortoises was found from 880 to 1,570 m elevation and was more abundant above 1,200 m than has been reported previously for Nevada. Tortoises were more abundant on NTS on the upper alluvial fans and slopes of mountains than in valley bottoms. They also were more common on or near limestone and dolomite mountains than on mountains of volcanic origin

  16. Hyperfine Induced Transitions as Diagnostics of Low Density Plasmas and Isotopic Abundance ratios.

    Science.gov (United States)

    Brage, T.; Judge, P. G.; Aboussaid, A.; Godefroid, M. R.; Jonsson, P.; Leckrone, D. S.

    1996-05-01

    We propose a new diagnostics of isotope abundance ratios and electron densities for low density plasmas, in the form of J = 0 -> J(') = 0 radiative transitions. These are usually viewed as being allowed only through two-photon decay, but they may also be induced by the hyperfine (HPF) interaction in atomic ions. This predicts a companion line to the E1] and M2 lines in the UV0.01 multiplet of ions isoelectronic to beryllium (e.g. C III, N IV, O V and Fe XXII) or magnesium (e.g. Si II, Ca IX, Fe XV and Ni XVII). As an example the companion line to the well known lambda lambda 1906.7,1908.7 lines in C III will be at 1909.597 Angstroms, but only present in the (13) C isotope (which has nuclear spin different from zero). We present new and accurate decay rates for the nsnp (3P^oJ) -> ns(2) (1S_{J('}=0)) transitions in ions of the Be (n=2) and Mg (n=3) isoelectronic sequences. We show that the HPF induced decay rates for the J = 0 -> J(') = 0 transitions are many orders of magnitude larger than those for the competing two-photon processes and, when present, are typically one or two orders of magnitude smaller than the decay rates of the magnetic quadrupole ( J = 2-> J(') = 0) transitions for these ions. We show that several of these HPF-induced transitions are of potential astrophysical interest, in ions of C, N, Na, Mg, Al, Si, K, Cr, Fe and Ni. We highlight those cases that may be of particular diagnostic value for determining isotopic abundance ratios and/or electron densities from UV or EUV emission line data. We present our atomic data in the form of scaling laws so that, given the isotopic nuclear spin and magnetic moment, a simple expression yields estimates for HPF induced decay rates. We examine some UV solar and nebular data in the light of these new results and suggest possible cases for future study. We could not find evidence for the existence of HPF induced lines in the spectra we examined, but we demonstrate that existing data have come close to providing

  17. ABUNDANCE AND ISOTOPIC COMPOSITION OF PLANKTONIC MICROCRUSTACEANS IN A CENTRAL AMAZON FLOODPLAIN LAKE: IMPLICATIONS FOR THE TROPHIC DYNAMICS OF THE PLANKTON COMMUNITY

    Directory of Open Access Journals (Sweden)

    Pedro Caraballo

    2016-01-01

    Full Text Available During the hydrological year from December 2007 to November 2008, monthly samplings in the pelagic, littoral and macrophytes zones were conducted in the Lago Catalão, a floodplain lake receiving a mixture of water from Negro and Solimões Rivers, in front of Manaus city. Taxonomic composition and their relative abundance of the planktonic microcrustaceans community was studied. Natural abundances of carbon (C and nitrogen (N stable isotopes were measured to indicate energy sources. Cladocerans were the most abundant, with a relative abundance of 60%, followed by the calanoid and cyclopoid copepods with relative abundances of 29% and 11%, respectively. Diaphanosoma spp. was the dominant cladoceran group during all the sampling periods. Cladocerans were also represented by Moina spp., Ceriodaphnia spp. and Daphnia gessneri. Three genera of calanoid copepods were found: Notodiaptomus spp, Rhacodiaptomus spp., and Argyrodiaptomus spp. The genus Mesocyclops spp. was identified among the cyclopoid copepods. Zooplankton δ13C values indicated that the aquatic macrophyte zone was distinct, with a mean of -27.31‰, which was more enriched than zooplankton in the pelagic and littoral zones, where they had mean δ13C values of -33.11 and -34.66‰, respectively. Overall, analysis of stable isotopes showed that regardless of the pathways, the initial source of carbon for the zooplankton was phytoplankton, with a minimal participation of heterotrophic bacteria.

  18. Relative abundance of mosquito species in Katsina Metropolis ...

    African Journals Online (AJOL)

    A study was conducted on the relative abundance of mosquito species, around selected areas of Katsina metropolis, Katsina State, Nigeria during the months of January, February, April and June 2010. Mosquitoes were collected from five sampling sites: Kofar Durbi, Kofar Kaura, Kofar Marusa, GRA and Layout. These were ...

  19. Species Composition, Relative Abundance and Distribution of the ...

    African Journals Online (AJOL)

    Species Composition, Relative Abundance and Distribution of the Avian Fauna of Entoto Natural Park and Escarpment, Addis Ababa. ... Eucalyptus plantation, soil erosion, deforestation, habitat fragmentation, settlement and land degradation were the main threats for the distribution of birds in the present study area.

  20. Effectiveness of leaded petrol phase-out in Tianjin, China based on the aerosol lead concentration and isotope abundance ratio

    International Nuclear Information System (INIS)

    Wang Wan; Liu Xiande; Zhao Liwei; Guo, Dongfa; Tian Xiaodan; Adams, Freddy

    2006-01-01

    The phase-out of leaded petrol has been a measure widely used to reduce atmospheric lead pollution. Since the 1980s, China began to promote unleaded petrol. In order to assess the effectiveness of the measure an isotope fingerprint technique was applied for aerosol samples in the city of Tianjin. After dilute acid leaching, the lead concentration and isotope abundance ratios were determined for 123 samples collected in Tianjin during eight years (1994-2001). The 206 Pb / 207 Pb ratio was lower in summer, when coal combustion emission was low and vehicle exhaust became more important, indicating that the 206 Pb / 207 Pb ratio of leaded petrol in Tianjin is lower than that of aerosol samples. The 206 Pb / 207 Pb ratio gradually increased from 1994 to 2001, a trend that suggests that the contribution from vehicle exhaust was diminishing. Overall, the measurements matched well with national statistical data of leaded and unleaded petrol production. After the nationwide switch to unleaded gasoline, comprehensive control measures are urgently needed to reduce air lead pollution in China, as aerosol lead reduced slightly but remains at a relatively high level

  1. A history of violence: Insights into post-accretionary heating in carbonaceous chondrites from volatile element abundances, Zn isotopes and water contents

    Science.gov (United States)

    Mahan, Brandon; Moynier, Frédéric; Beck, Pierre; Pringle, Emily A.; Siebert, Julien

    2018-01-01

    Carbonaceous chondrites (CCs) may have been the carriers of water, volatile and moderately volatile elements to Earth. Investigating the abundances of these elements, their relative volatility, and isotopes of state-change tracer elements such as Zn, and linking these observations to water contents, provide vital information on the processes that govern the abundances and isotopic signatures of these species in CCs and other planetary bodies. Here we report Zn isotopic data for 28 CCs (20 CM, 6 CR, 1 C2-ung, and 1 CV3), as well as trace element data for Zn, In, Sn, Tl, Pb, and Bi in 16 samples (8 CM, 6 CR, 1 C2-ung, and 1 CV3), that display a range of elemental abundances from case-normative to intensely depleted. We use these data, water content data from literature and Zn isotopes to investigate volatile depletions and to discern between closed and open system heating. Trace element data have been used to construct relative volatility scales among the elements for the CM and CR chondrites. From least volatile to most, the scale in CM chondrites is Pb-Sn-Bi-In-Zn-Tl, and for CR chondrites it is Tl-Zn-Sn-Pb-Bi-In. These observations suggest that heated CM and CR chondrites underwent volatile loss under different conditions to one another and to that of the solar nebula, e.g. differing oxygen fugacities. Furthermore, the most water and volatile depleted samples are highly enriched in the heavy isotopes of Zn. Taken together, these lines of evidence strongly indicate that heated CM and CR chondrites incurred open system heating, stripping them of water and volatiles concomitantly, during post-accretionary shock impact(s).

  2. Natural abundance N stable isotopes in plants and soils as an indicator of N deposition hotspots in urban environments

    Science.gov (United States)

    Trammell, T. L.

    2017-12-01

    The natural abundance of stable isotopes in plants and soils has been utilized to understand ecological phenomenon. Foliar δ15N is an integrator of soil δ15N, atmospheric N sources, and fractionation processes that occur during plant N uptake, plant N assimilation, and mycorrhizal associations. The amount of reactive N in the environment has greatly increased due to human activities, and urban ecosystems experience excess N deposition that can have cascading effects on plants and soils. Foliar δ15N has been shown to increase with increasing N deposition and nitrification rates suggesting increased foliar δ15N occurs with greater N inputs as a result of accelerated soil N cycling. Thus, foliar δ15N can be an indication of soil N availability for plant uptake and soil N cycling rates, since high N availability results in increased soil N cycling and subsequent loss of 14N. Limited research has utilized foliar and soil δ15N in urban forests to assess the importance of plant uptake of atmospheric N deposition and to gain insight about ecosystem processes. Previous investigations found foliar δ15N of mature trees in urban forests is not only related to elevated pollutant-derived N deposition, but also to soil N availability and soil N cycling rates. Similarly, enriched foliar δ15N of urban saplings was attributed to soil characteristics that indicated higher nitrification, thus, greater nitrate leaching and low N retention in the urban soils. These studies demonstrate the need for measuring the δ15N of various plant and soil N sources while simultaneously measuring soil N processes (e.g., net nitrification rates) in order to use natural abundance δ15N of plants and soils to assess N sources and cycling in urban forests. A conceptual framework that illustrates biogenic and anthropogenic controls on nitrogen isotope composition in urban plants and soils will be presented along with foliar and soil δ15N from urban forests across several cities as a proof of

  3. Penguin tissue as a proxy for relative krill abundance in East Antarctica during the Holocene.

    Science.gov (United States)

    Huang, Tao; Sun, Liguang; Long, Nanye; Wang, Yuhong; Huang, Wen

    2013-09-30

    Antarctic krill (Euphausia superba) is a key component of the Southern Ocean food web. It supports a large number of upper trophic-level predators, and is also a major fishery resource. Understanding changes in krill abundance has long been a priority for research and conservation in the Southern Ocean. In this study, we performed stable isotope analyses on ancient Adélie penguin tissues and inferred relative krill abundance during the Holocene epoch from paleodiets of Adélie penguin (Pygoscelis adeliae), using inverse of δ¹⁵N (ratio of ¹⁵N/¹⁴N) value as a proxy. We find that variations in krill abundance during the Holocene are in accord with episodes of regional climate changes, showing greater krill abundance in cold periods. Moreover, the low δ¹⁵N values found in modern Adélie penguins indicate relatively high krill availability, which supports the hypothesis of krill surplus in modern ages due to recent hunt for krill-eating seals and whales by humans.

  4. Distribution and isotopic abundance of sulphur in recent marine sediments off southern California

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, I R; Emergy, K O; Rittenberg, S C

    1963-01-01

    Analyses of sulphur compounds in basin sediments off southern California indicate that elemental sulphur, free sulphide, hydrotroilite, organic sulphur, sulphate and pyrite are present in quantities that vary with environment and depth in the sediments. Pyrite is generally the most abundant form, occurring in oxidizing as well as in reducing sediments and often constituting 90% of total sulphur. A material balance indicates that the total sulphur content is far in excess of the sulphate-sulphur initially trapped in the interstitial water. This evidence, together with failure to detect significant alternate sources, suggests that sulphate-sulphur is extracted from the overlying sea water at the sediment-water interface. Isotope measurements confirm many of the conclusions suggested by the quantitative chemical analyses. The show that biological sulphate reduction is the single most important process in the sulphur cycle. The sulphide released is converted to hydrotrolite and then to pyrite. Elemental and organic sulphur appear to be continually forming and reacting in the sediment column. The organic sulphur released from decaying organic matter apparently plays only a small role in the sulphur economy. Enrichment in S/sup 32/ ranging from 9 to 62% was measured in pyrite fragments, a spread similar to that previously observed in ancient sediments. Data from field and laboratory experiments were combined to determine rate of sulphate reduction, number of sulphate reducing bacteria and the amount of organic matter decomposed during sulphate reduction in the sediment, as well as rate of renewal of water in the basins. The results suggest that the methods used may have many applications for elucidating in situ rate processes.

  5. Carbon-13 kinetic isotope effects in the decarbonylations of lactic acid containing 13C at the natural abundance level

    International Nuclear Information System (INIS)

    Zielinski, M.; Czarnota, G.; Papiernik-Zielinska, H.

    1992-01-01

    The 13 C kinetic isotope fractionation in the decarbonylation of lactic acid of natural isotopic composition by sulfuric acid has been studied in the temperature range of 20-80 deg C. The 13 C (1) isotope separation in the decarbonylation of lactic acid by concentrated sulfuric acid depends strongly on the temperature above 40 deg C. Below this temperature the 13 C isotope effect in the decarbonylation of lactic acid by concentrated sulfuric acid is normal similarly as has been found in the decarbonylation of lactic [1- 14 C] acid. The experimental values of k (12C) /k (13C) ratios of isotopic rate constants for 12 C and 13 C are close to, but slightly higher than theoretical 13 C-kinetic isotope effects calculated (neglecting tunneling) under the asumption that the C (1) -OH bond is broken in the rate-controlling step of the dehydration reaction. Dilution of concentrated sulfuric acid with water up to 1.4 molar (H 2 O)/(H 2 SO 4 ) ratio caused the increase of the 13 C isotope fractionation from 1.0273 found in concentrated sulfuric acid at 80.5 deg C to 1.0536±0.0008 (at 80.6 deg C). A discussion of the abnormally high temperature dependence of 14 C and 13 C isotope fractionation in this reaction and the discussion of the problem of relative 14 C/ 13 C kinetic isotope effects is given. (author) 18 refs.; 2 tabs

  6. Relation between grade and abundance of manganese nodules

    Digital Repository Service at National Institute of Oceanography (India)

    Sudhakar, M.

    Data from more than 1000 locations in the Central Indian Ocean Basin (CIOB) where both bulk nodule chemistry and abundance were determined and utilized to study the relationship between grade and abundance of manganese nodule deposits. Grade...

  7. Characterization of uranium isotopic abundances in depleted uranium metal assay standard 115

    International Nuclear Information System (INIS)

    Mathew, K.J.; Singleton, G.L.; Essex, R.M.; Hasozbek, A.; Orlowicz, G.; Soriano, M.

    2013-01-01

    Certified reference material (CRM) 115, Uranium (Depleted) Metal (Uranium Assay Standard), was analyzed using a TRITON Thermal Ionization Mass Spectrometer to characterize the uranium isotope-amount ratios. The certified 235 U/ 238 U 'major' isotope-amount ratio of 0.0020337 (12) in CRM 115 was determined using the total evaporation (TE) and the modified total evaporation (MTE) analytical techniques. In the MTE method, the total evaporation process is interrupted on a regular basis to allow correction of background from peak tailing, internal calibration of the secondary electron multiplier detector versus the Faraday cups, peak-centering, and ion source re-focusing. For the 'minor' 234 U/ 238 U and 236 U/ 238 U isotope-amount ratio measurements using MTE, precision and accuracy comparable to conventional analyses are achieved, without compromising the quality of the 235 U/ 238 U isotope-amount ratios. Characterized values of the 234 U/ 238 U and 236 U/ 238 U isotope-amount ratios in CRM 115 are 0.000007545 (10) and 0.000032213 (84), respectively. The 233 U/ 238 U isotope-amount ratio in CRM 115 is estimated to be -9 . The homogeneity of the CRM 115 materials is established through the absence of any statistically significant unit-to-unit variation in the uranium isotope-amount ratios. The measurements leading to the certification of uranium isotope-amount ratios are discussed. (author)

  8. Coupled Mo-U abundances and isotopes in a small marine euxinic basin: Constraints on processes in euxinic basins

    Science.gov (United States)

    Bura-Nakić, Elvira; Andersen, Morten B.; Archer, Corey; de Souza, Gregory F.; Marguš, Marija; Vance, Derek

    2018-02-01

    Sedimentary molybdenum (Mo) and uranium (U) abundances, as well as their isotope systematics, are used to reconstruct the evolution of the oxygenation state of the surface Earth from the geological record. Their utility in this endeavour must be underpinned by a thorough understanding of their behaviour in modern settings. In this study, Mo-U concentrations and their isotope compositions were measured in the water column, sinking particles, sediments and pore waters of the marine euxinic Lake Rogoznica (Adriatic Sea, Croatia) over a two year period, with the aim of shedding light on the specific processes that control Mo-U accumulation and isotope fractionations in anoxic sediment. Lake Rogoznica is a 15 m deep stratified sea-lake that is anoxic and euxinic at depth. The deep euxinic part of the lake generally shows Mo depletions consistent with near-quantitative Mo removal and uptake into sediments, with Mo isotope compositions close to the oceanic composition. The data also, however, show evidence for periodic additions of isotopically light Mo to the lake waters, possibly released from authigenic precipitates formed in the upper oxic layer and subsequently processed through the euxinic layer. The data also show evidence for a small isotopic offset (∼0.3‰ on 98Mo/95Mo) between particulate and dissolved Mo, even at highest sulfide concentrations, suggesting minor Mo isotope fractionation during uptake into euxinic sediments. Uranium concentrations decrease towards the bottom of the lake, where it also becomes isotopically lighter. The U systematics in the lake show clear evidence for a dominant U removal mechanism via diffusion into, and precipitation in, euxinic sediments, though the diffusion profile is mixed away under conditions of increased density stratification between an upper oxic and lower anoxic layer. The U diffusion-driven precipitation is best described with an effective 238U/235U fractionation of +0.6‰, in line with other studied euxinic

  9. Oxygen isotopic abundances in calcium- aluminum-rich inclusions from ordinary chondrites: implications for nebular heterogeneity.

    Science.gov (United States)

    McKeegan, K D; Leshin, L A; Russell, S S; MacPherson, G J

    1998-04-17

    The oxygen isotopic compositions of two calcium-aluminum-rich inclusions (CAIs) from the unequilibrated ordinary chondrite meteorites Quinyambie and Semarkona are enriched in 16O by an amount similar to that in CAIs from carbonaceous chondrites. This may indicate that most CAIs formed in a restricted region of the solar nebula and were then unevenly distributed throughout the various chondrite accretion regions. The Semarkona CAI is isotopically homogeneous and contains highly 16O-enriched melilite, supporting the hypothesis that all CAI minerals were originally 16O-rich, but that in most carbonaceous chondrite inclusions some minerals exchanged oxygen isotopes with an external reservoir following crystallization.

  10. Relative foraminiferan abundance as an indicator of seagrass sediment health:

    Science.gov (United States)

    Cajandig, P.; Quiros, A.; Nolan, H.; Tallman, R.; Cooper, N.; Ayala, J.; Courtier, C.

    2013-12-01

    Authors: Patrick Cajandig*, Jose Ayala**, Nathaniel Cooper**, Catherine Courtier**, Hannah Nolan**, Rachelle Tallman**, T.E. Angela L. Quiros** * Davis High-School CA, **University of California Santa Cruz, Ecology and Evolutionary Biology Department Seagrasses are a key component in coastal ecosystems. Found in shallow marine environments, they make a large contribution to coastal ecosystem health by sustaining water quality, stabilizing the sea bottom, and providing habitat as well as food for other organisms. Seagrasses accumulate tiny grains of sediment, increasing water clarity. Just like barren hills are prone to erosion compared to vegetated, rooted down hills, we find a similar situation in the ocean. Seagrasses have broad roots that extend vertically and horizontally to help stabilize the seabed. Seagrasses support a whole ecosystem, because some organisms feed off of the seagrass alone, while others feed off the inhabitants of the seagrass. The quality of sediment is a vital part of seagrass health, just like nutrient rich soils are important to land plants. But what in seagrass sediment is a good indication of health? We hypothesize that seagrass health measures such as percent cover and seagrass species diversity are related to the abundance of foraminiferans relative to other seagrass sediment components. My mentor, T. E. Angela L. Quiros, from the University of California, Santa Cruz (UCSC), collected the sediment samples from seagrass beds in the Philippines. Samples were dried and brought to UCSC for sediment sieving. We used different sized sieves to sort the sediment. These sieves ranged from coarse to very fine sieves (Phi -2.0 (coarse) through +3.0 (fine) going in 0.5 intervals on a log scale). We weighed the sediment that was caught in each tray and separated them into bags of different size classes. To analyze each sample, we subsampled four size classes (Phi's -2.0, -1.5,-1.0, 0.0), and used a dissecting scope to identify and then weigh the

  11. Study on strontium isotope abundance-ratio measurements by using a 13-MeV proton beam

    Science.gov (United States)

    Jeong, Cheol-Ki; Jang, Han; Lee, Goung-Jin

    2016-09-01

    The Rb-Sr dating method is used in dating Paleozoic and Precambrian rocks. This method measures the 87Rb and the 87Sr concentrations by using thermal ionization mass spectrometry (TIMS) [J. Hefne et al., Inter. J. Phys. Sci. 3(1), 28 (2008)]. In addition, it calculates the initial 87Sr/86Sr ratio to increase the reliability of Rb-Sr dating. In this study, the 87Sr/86Sr ratio was measured by using a 13-MeV proton accelerator. Proton kinetic energies are in the range of tens of megaelectronvolts, and protons have large absorption cross-sections for ( p, n) reactions with most substances. After absorbing a proton with such a high kinetic energy, an element is converted into a nuclide with its atomic number increased by one via nuclear transmutation. These nuclides usually have short half-lives and return to the original state through radioactive decay. When a strontium sample is irradiated with protons, nuclear transmutation occurs; thus, the strontium isotope present in the sample changes to a yttrium isotope, which is an activated radioisotope. Based on this, the 87Sr/86Sr ratio was calculated by analyzing the gamma-rays emitted by each yttrium isotope. The KIRAMS-13 cyclotron at the Cyclotron Center of Chosun University, where 13-MeV protons can be extracted, was utilized in our experiment. The 87Sr/86Sr isotope ratio was computed for samples irradiated with these protons, and the result was similar to the isotope ratio for the Standard Reference Material, i.e., 98.2 ± 3.4%. As part of the analysis, proton activation analyses were performed using 13-MeV protons, and the experimental results of this research suggest a possible approach for measuring the strontium-isotope abundance ratio of samples.

  12. Accurate experimental determination of the isotope effects on the triple point temperature of water. I. Dependence on the "2H abundance

    International Nuclear Information System (INIS)

    Faghihi, V.; Aerts-Bijma, A.T.; Jansen, H.G.; Spriensma, J.J.; Meijer, H.A.J.; Peruzzi, A.; Geel, J. van

    2015-01-01

    Variation in the isotopic composition of water is one of the major contributors to uncertainty in the realization of the triple point of water (TPW). Although the dependence of the TPW on the isotopic composition of the water has been known for years, there is still a lack of a detailed and accurate experimental determination of the values for the correction constants. This paper is the first of two articles (Part I and Part II) that address quantification of isotope abundance effects on the triple point temperature of water. In this paper, we describe our experimental assessment of the "2H isotope effect. We manufactured five triple point cells with prepared water mixtures with a range of "2H isotopic abundances encompassing widely the natural abundance range, while the "1"8O and "1"7O isotopic abundance were kept approximately constant and the "1"8O - "1"7O ratio was close to the Meijer-Li relationship for natural waters. The selected range of "2H isotopic abundances led to cells that realised TPW temperatures between approximately -140 μK to + 2500 μK with respect to the TPW temperature as realized by VSMOW (Vienna Standard Mean Ocean Water). Our experiment led to determination of the value for the δ"2H correction parameter of A_2_H = 673 μK/(per thousand deviation of δ"2H from VSMOW) with a combined uncertainty of 4 μK (k = 1, or 1 s). (authors)

  13. Determination of Isotopic Abundance of 2H, 13C, 18O, and 37Cl in Biofield Energy Treated Dichlorophenol Isomers

    OpenAIRE

    Branton, Alice; Trivedi, Dahryn; Nayak, Gopal; Trivedi, Mahendra; Saikia, Gunin; Jana, Snehasis

    2016-01-01

    2,4-Dichlorophenol (2,4-DCP) and 2,6-dichlorophenol (2,6-DCP) are two isomers of dichlorophenols, have been used as preservative agents for wood, paints, vegetable fibers and as intermediates in the production of pharmaceuticals and dyes. The aim of the study was to evaluate the impact of biofield energy treatment on the isotopic abundance ratios of 2H/1H or 13C/12C, and 18O/16O or 37Cl/35Cl, in dichlorophenol isomers using gas chromatography-mass spectrometry (GC-MS). The 2,4-DCP and 2,6-DCP...

  14. Isotopic abundance measurements on solid nuclear-type samples by glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Betti, M.; Rasmussen, G.; Koch, L.

    1996-01-01

    A double-focusing glow discharge mass spectrometer (GDMS) installed in a glovebox for nuclear sample screening has been employed for isotopic measurements. Isotopic compositions of zirconium, silicon, lithium, boron, uranium and plutonium which are elements of nuclear concern have been determined. Interferences arising from the matrix sample and the discharge gas (Ar) for each of these elements are discussed. The GDMS results are compared with those from thermal ionization mass spectrometry (TIMS). For boron and lithium at μg/g-ng/g levels, the two methods gave results in good agreement. In samples containing uranium the isotopic composition obtained by GDMS was in agreement with those from TIMS independently of the enrichment. Attempts for the determination of plutonium isotopic composition were also made. In this case, due to the interferences of uranium at mass 238 and americium at mass 241, the GDMS raw data are complementary with those values obtained from physical non-destructive techniques. (orig.). With 2 figs., 4 tabs

  15. Sensitive lifetime measurement of excited states of low-abundant isotopes via the (p,p{sup '}γ) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Hennig, Andreas; Derya, Vera; Pickstone, Simon G.; Spieker, Mark; Zilges, Andreas [Institute for Nuclear Physics, University of Cologne (Germany); Mineva, Milena N. [INRNE, Bulgarian Academy of Sciences, Sofia (Bulgaria); Petkov, Pavel [Institute for Nuclear Physics, University of Cologne (Germany); INRNE, Bulgarian Academy of Sciences, Sofia (Bulgaria)

    2015-07-01

    Absolute transition matrix elements are valuable observables in nuclear-structure physics since they are directly related to the nuclear wave functions. A key ingredient to determine transition matrix elements is the measurement of lifetimes of excited states. In a recent experiment, we extracted the lifetimes of 30 excited states of the low-abundant isotope {sup 96}Ru utilizing the Doppler-shift attenuation method (DSAM) in an inelastic proton-scattering experiment and taking advantage of the proton-γ coincidence technique. In contrast to the DSAM technique following inelastic neutron scattering, which was frequently performed to extract comprehensive lifetime information in the sub-picosecond regime, the (p,p{sup '}γ) reaction requires a much less amount of target material and is thus especially suited to investigate low-abundant isotopes. In this contribution, the (p,p{sup '}γ) method for lifetime measurements is presented and the results of recent experiments on {sup 96}Ru, {sup 94}Zr, and {sup 112,114}Sn are shown.

  16. Evaluation of TASTEX task H: measurement of plutonium isotopic abundances by gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Gunnink, R.; Prindle, A.L.; Asakura, Y.; Masui, J.; Ishiguro, N.; Kawasaki, A.; Kataoka, S.

    1981-10-01

    This report describes a computer-based gamma spectrometer system that was developed for measuring isotopic and total plutonium concentrations in nitric acid solutions. The system was installed at the Tokai reprocessing plant where it is undergoing testing and evaluation as part of the Tokai Advanced Safeguards Exercise (TASTEX). Objectives of TASTEX Task H, High-Resolution Gamma Spectrometer for Plutonium Isotopic Analysis, the methods and equipment used, the installation and calibration of the system, and the measurements obtained from several reprocessing campaigns are discussed and described. In general, we find that measurements for gamma spectroscopy agree well with those of mass spectrometry and of other chemical analysis. The system measures both freshly processed plutonium from the product accountability tank and aged plutonium solutions from storage tanks. 14 figures, 15 tables

  17. Relative abundance and distribution of bacteria in the gut of ...

    African Journals Online (AJOL)

    Escherichia coli, Aeromonas hydrophila, Salmonella typhi and Pseudomonas aeruginosa were the most abundant species in the samples from Epe Lagoon while Escherichia coli, Aeromonas hydrophila, Proteus vulgaris and Pseudomonas aeruginosa were predominant in Badagry Creek. It was noteworthy that Citrobacter ...

  18. Abundance and Isotopic Composition of Gases in the Martian Atmosphere from the Curiosity Rover

    Science.gov (United States)

    Mahaffy, Paul R.; Webster, Christopher R.; Atreya, Sushil K.; Franz, Heather; Wong, Michael; Conrad, Pamela G.; Harpold, Dan; Jones, John J.; Leshin, Laurie A.; Manning, Heidi; Owen, Tobias; Pepin, Robert O.; Squyres, Steven; Trainer, Melissa; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Grotzinger, John; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Lasue, Jérémie; Lee, Qiu-Mei; Maurice, Sylvestre; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Dromart, Gilles; Robert, François; Sautter, Violaine; Le Mouélic, Stéphane; Mangold, Nicolas; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Wiens, Roger C.; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Jones, Andrea; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Vasavada, Ashwin R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Williams, Rebecca M. E.; Yingst, Aileen; Lewis, Kevin; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mueller-Mellin, Reinhold; Wimmer-Schweingruber, Robert; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

    2013-07-01

    Volume mixing and isotope ratios secured with repeated atmospheric measurements taken with the Sample Analysis at Mars instrument suite on the Curiosity rover are: carbon dioxide (CO2), 0.960(±0.007); argon-40 (40Ar), 0.0193(±0.0001); nitrogen (N2), 0.0189(±0.0003); oxygen, 1.45(±0.09) × 10-3; carbon monoxide, < 1.0 × 10-3; and 40Ar/36Ar, 1.9(±0.3) × 103. The 40Ar/N2 ratio is 1.7 times greater and the 40Ar/36Ar ratio 1.6 times lower than values reported by the Viking Lander mass spectrometer in 1976, whereas other values are generally consistent with Viking and remote sensing observations. The 40Ar/36Ar ratio is consistent with martian meteoritic values, which provides additional strong support for a martian origin of these rocks. The isotopic signature δ13C from CO2 of ~45 per mil is independently measured with two instruments. This heavy isotope enrichment in carbon supports the hypothesis of substantial atmospheric loss.

  19. Helium Isotopes and Noble Gas Abundances of Cave Dripping Water in Three Caves in East Asia

    Science.gov (United States)

    Chen, A. T.; Shen, C. C.; Tan, M.; Li, T.; Uemura, R.; Asami, R.

    2015-12-01

    Paleo-temperature recorded in nature archives is a critical parameter to understand climate change in the past. With advantages of unique inert chemical characteristics and sensitive solubilities with temperature, dissolved noble gases in speleothem inclusion water were recently proposed to retrieve terrestrial temperature history. In order to accurately apply this newly-developed speleothem noble gas temperature (NGT) as a reliable proxy, a fundamental issue about behaviors of noble gases in the karst should be first clarified. In this study, we measured noble gas contents in air and dripping water to evaluate any ratio deviation between noble gases. Cave dripping water samples was collected from three selected caves, Shihua Cave in northern China, Furong Cave in southwestern, and Gyukusen Cave in an island located in the western Pacific. For these caves are characterized by a thorough mixing and long-term storage of waters in a karst aquifer by the absence of seasonal oxygen isotope shifts. Ratios of dripping water noble gases are statistically insignificant from air data. Helium isotopic ratios in the dripping water samples match air value. The results indicate that elemental and isotopic signatures of noble gases from air can be frankly preserved in the epikarst and support the fidelity of NGT techniques.

  20. Monsoon Variability In The Western Arabian Sea During Last 10,000 Years BP: A Planktic Foraminiferal Abundances And It's Stable Isotope Records

    Science.gov (United States)

    Singh, A. K.; Tiwari, M.; Sinha, D. K.; Ramesh, R.

    2007-12-01

    : The western Arabian Sea responds to the southwest monsoon winds by upwelling colder and nutrient rich waters from the deeper layers, causing a reduction in the sea surface temperature and enhanced biological productivity. A number of paleoclimatic studies have been carried out in this region to elucidate past monsoon variability (Sirocco et al., 1993; Gupta et al, 2003; Tiwari, 2005; Saher et.al.; 2007). Globigerina bulloides, a planktic foraminiferal species normally inhabiting surface ocean waters in temperate latitudes ( Be and Tolderlund , 1977) also becomes abundant at tropical latitudes upwelling occurs, and in these cases its abundance can exceed considerably. The conspicuous fluctuation in the abundance of Gg.bulloides during upwelling and non upwelling intervals is established through several studies ( Thiede and Junger, 1980, Gupta et al, 2003) This robust relation has been used as a proxy for wind velocity at several different times in the past in the Arabian Sea (Anderson et.al., 2002). A significant result from some of these centennially resolved Holocene records is declining abundance of Globigerina bulloides which is paralleled by reduced insolation record and this has been inferred as declining strength of Asian Monsoon. We are presenting here the data from the core SS4018 from near the Gulf of Aden, Western Arabian Sea taken at a water depth of 2830 m, precisely dated by the radiocarbon method using Accelerator Mass Spectrometry on planktonic foraminiferal separates. We have carried out the planktic foraminiferal census counts for each sample to know the relative abundance of key species. In addition to this, we have also employed multi- proxy approach such as oxygen and carbon isotopes of planktic foraminiferal tests, TOC, CaCO3 (%) to strengthen our interpretation and also to understand the relationships amongst the proxies themselves. Abundance of the key planktic foraminiferal species and other proxy records reveal at least 3 major climatic

  1. Accurate experimental determination of the isotope effects on the triple point temperature of water. I. Dependence on the 2H abundance

    Science.gov (United States)

    Faghihi, V.; Peruzzi, A.; Aerts-Bijma, A. T.; Jansen, H. G.; Spriensma, J. J.; van Geel, J.; Meijer, H. A. J.

    2015-12-01

    Variation in the isotopic composition of water is one of the major contributors to uncertainty in the realization of the triple point of water (TPW). Although the dependence of the TPW on the isotopic composition of the water has been known for years, there is still a lack of a detailed and accurate experimental determination of the values for the correction constants. This paper is the first of two articles (Part I and Part II) that address quantification of isotope abundance effects on the triple point temperature of water. In this paper, we describe our experimental assessment of the 2H isotope effect. We manufactured five triple point cells with prepared water mixtures with a range of 2H isotopic abundances encompassing widely the natural abundance range, while the 18O and 17O isotopic abundance were kept approximately constant and the 18O  -  17O ratio was close to the Meijer-Li relationship for natural waters. The selected range of 2H isotopic abundances led to cells that realised TPW temperatures between approximately  -140 μK to  +2500 μK with respect to the TPW temperature as realized by VSMOW (Vienna Standard Mean Ocean Water). Our experiment led to determination of the value for the δ2H correction parameter of A2H  =  673 μK / (‰ deviation of δ2H from VSMOW) with a combined uncertainty of 4 μK (k  =  1, or 1σ).

  2. Authentication of origins of fermentive ethanol in Philippine-made beverages by C,H,O isotope abundances

    International Nuclear Information System (INIS)

    Sucgang, Raymond J.; Morco, Ryan; Bautista, Angel; Laguitan, Arlin; Sevilla III, Fortunato

    2010-01-01

    This paper demonstrates the expediency of radiocarbon liquid scintillation counting for detection of synthetic ethanol adulteration in Philippine-manufactured wines/alcoholic beverages. The impure wines are distinguished from the pure beverages by radiocarbon assay, taking advantage of the anticipated minor 1 4Carbon content of synthetic ethyl alcohol in comparison with the natural 1 4C abundance of the plant-derived, biogenic products. Biogenic samples give 12-15 dpm/g C activities, while synthetic samples exhibits 0-2 dpm/g C activities. The research moreover explores the utility of Deuterium, Oxygen 16 and 1 3Carbon/ 1 2Carbon isotope ratio analysis in the authentication of the botanical and geographical origins of beverages. Initial investigations revealed the mean of δ 1 8O in the Metro Manila area for precipitation, surface waters and ground waters to be -6.09 ± 2.9, -1.59 ± 2.2, and -6.64 ± 0.7 per mil.respectively. δ 2 H in Metro Manila for precipitation, surface waters and ground waters were -43.8 ± 1.2,-11.9 ± 16.2, -45.0 ± 4.8 per mil respectively. Vital information such as detection of illegal dilution with water, or enrichment using other sugars before and after fermentation, misrepresentation of geographical origin, and adulteration with petroleum-derived ethanol can be generated from the isotopic data. (author)

  3. Quantifying Uranium Isotope Ratios Using Resonance Ionization Mass Spectrometry: The Influence of Laser Parameters on Relative Ionization Probability

    Energy Technology Data Exchange (ETDEWEB)

    Isselhardt, Brett H. [Univ. of California, Berkeley, CA (United States)

    2011-09-01

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure relative uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process to provide a distinction between uranium atoms and potential isobars without the aid of chemical purification and separation. We explore the laser parameters critical to the ionization process and their effects on the measured isotope ratio. Specifically, the use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of 235U/238U ratios to decrease laser-induced isotopic fractionation. By broadening the bandwidth of the first laser in a 3-color, 3-photon ionization process from a bandwidth of 1.8 GHz to about 10 GHz, the variation in sequential relative isotope abundance measurements decreased from >10% to less than 0.5%. This procedure was demonstrated for the direct interrogation of uranium oxide targets with essentially no sample preparation. A rate equation model for predicting the relative ionization probability has been developed to study the effect of variation in laser parameters on the measured isotope ratio. This work demonstrates that RIMS can be used for the robust measurement of uranium isotope ratios.

  4. Laser spectrometry applied to the simultaneous determination of the δ2H, δ17O, and δ18O isotope abundances in water

    International Nuclear Information System (INIS)

    Kerstel, E.R.T.; Trigt, R. van; Dam, N.; Reuss, J.; Meijer, H.A.J.

    2001-01-01

    We demonstrate the first successful application of infrared laser spectrometry to the accurate, simultaneous determination of the relative 2 H/ 1 H, 17 O/ 16 O, and 18 O/ 16 O isotope abundance ratios in natural water. The method uses a narrow line width color center laser to record the direct absorption spectrum of low-pressure gas-phase water samples (presently 10 μl liquid) in the 3μm spectral region. The precision of the spectroscopic technique is shown to be 0.7 per mille for δ 2 H and 0.5 per mille for δ 17 O and δ 18 O, while the calibrated accuracy for natural waters amounts to about 3 per mille and 1 per mille, respectively. (author)

  5. The abundance properties of nearby late-type galaxies. II. The relation between abundance distributions and surface brightness profiles

    International Nuclear Information System (INIS)

    Pilyugin, L. S.; Grebel, E. K.; Zinchenko, I. A.; Kniazev, A. Y.

    2014-01-01

    The relations between oxygen abundance and disk surface brightness (OH–SB relation) in the infrared W1 band are examined for nearby late-type galaxies. The oxygen abundances were presented in Paper I. The photometric characteristics of the disks are inferred here using photometric maps from the literature through bulge-disk decomposition. We find evidence that the OH–SB relation is not unique but depends on the galactocentric distance r (taken as a fraction of the optical radius R 25 ) and on the properties of a galaxy: the disk scale length h and the morphological T-type. We suggest a general, four-dimensional OH–SB relation with the values r, h, and T as parameters. The parametric OH–SB relation reproduces the observed data better than a simple, one-parameter relation; the deviations resulting when using our parametric relation are smaller by a factor of ∼1.4 than that of the simple relation. The influence of the parameters on the OH–SB relation varies with galactocentric distance. The influence of the T-type on the OH–SB relation is negligible at the centers of galaxies and increases with galactocentric distance. In contrast, the influence of the disk scale length on the OH–SB relation is at a maximum at the centers of galaxies and decreases with galactocentric distance, disappearing at the optical edges of galaxies. Two-dimensional relations can be used to reproduce the observed data at the optical edges of the disks and at the centers of the disks. The disk scale length should be used as a second parameter in the OH–SB relation at the center of the disk while the morphological T-type should be used as a second parameter in the relation at optical edge of the disk. The relations between oxygen abundance and disk surface brightness in the optical B and infrared K bands at the center of the disk and at optical edge of the disk are also considered. The general properties of the abundance–surface brightness relations are similar for the three

  6. In-plant measurements of gamma-ray transmissions for precise K-edge and passive assay of plutonium concentration and isotopic abundance in product solutions at the Tokai Reprocessing Plant

    International Nuclear Information System (INIS)

    Asakura, Y.; Kondo, I.; Masui, J.; Shoji, K.; Russo, P.A.; Hsue, S.T.; Sprinkle, J.K. Jr.; Johnson, S.S.

    1982-01-01

    A field test has been carried out for more than 2 years for determination of plutonium concentration by K-edge absorption densitometry and for determination of plutonium isotopic abundance by transmission-corrected passive gamma-ray spectrometry. This system was designed and built at Los Alamos National Laboratory and installed at the Tokai reprocessing plant of the Power Reactor and Nuclear Fuel Development Corporation as a part of the Tokai Advanced Safeguards Technology Exercise (TASTEX). For K-edge measurement of plutonium concentration, the transmissions at two discrete gamma-ray energies are measured using the 121.1- and 122.1-keV gamma rays from 75 Se and 57 Co. Intensities of the plutonium passive gamma rays in the energy regions between 38 and 51 keV and between 129 and 153 keV are used for determination of the isotopic abundances. More than 200 product solution samples have been measured in a timely fashion during these 2 years. The relative precisions and accuracies of the plutonium concentration measurement are shown to be within 0.6% (1 sigma) in these applications, and those for plutonium isotopic abundances are within 3% for 238 Pu, 0.4% for 239 Pu, 1.2% for 240 Pu, 1.3% for 241 Pu, and 7% for 242 Pu. The time required is 10 min for the concentration assay, 10 min for the isotopics assay, and about 15 min for handling procedures in the laboratory

  7. Isotopic abundance of 13 C and contribution of eucalyptus biomass to soil organic matter conversion

    Directory of Open Access Journals (Sweden)

    Fabiane Figueiredo Severo

    Full Text Available ABSTRACT: It has become possible to evaluate the conversion of soil organic matter (SOM in pastures and arboreal crops due to the difference between the photosynthetic cycles of Eucalyptus (C3 and most grasses (C4. The auto analyzer method coupled to the IRMS (Isotope Ratio Mass Spectrometer in the present study evaluated the 13C content in soil profiles of Eucalyptus plantations of different ages (2, 10 and 21 years, in natural regeneration areas and natural grazing fields, and estimated the SOM conversion of each crop type of. The initial management of all sampled areas was natural pasture. The following profile layers were evaluated: 0-5, 5-10, 10-20, 20-30, 30-40, 40-50, 50-70 and 70-90cm, and the contribution of Eucalyptus biomass over the years of farming was estimated in the SOM conversion process. After 2 years of planting Eucalyptus, the beginning of pasture carbon conversion process occurred in the surface layer (0-5cm. Ten years after planting, the process of converting organic matter by arboreal crops reached the layers up to 20cm. After 21 years of planting and in natural regeneration areas, the entire profile has already been changed by planting Eucalyptus and native tree species.

  8. Medical Isotopes Production Project: Molybdenum-99 and related isotopes: Environmental Impact Statement, Volume I

    International Nuclear Information System (INIS)

    1996-04-01

    This Environmental Impact Statement (EIS) provides environmental and technical information concerning the U.S. Department of Energy's (DOE) proposal to establish a domestic source to produce molybdenum-99 (Mo-99) and related medical isotopes (iodine-131, xenon-133 and iodine-125). Mo-99, a radioactive isotope of the element molybdenum, decays to form metastable technetium-99 (Tc-99m), a radioactive isotope used thousands of times daily in medical diagnostic procedures in the U.S. Currently, all Mo-99 used in the U.S. is obtained from a single Canadian source. DOE is pursuing the Medical Isotopes Production Project in order to ensure that a reliable supply of Mo-99 is available to the U.S. medical community. Under DOE's preferred alternative, the Chemistry and Metallurgy Research Facility at the Los Alamos National Laboratory (LANL) and the Annular Core Research Reactor and Hot Cell Facility at Sandia National Laboratories/New Mexico (SNL/NM) would be used for production of the medical isotopes. In addition to the preferred alternative, three other reasonable alternatives and a no action alternative are analyzed in detail. The sites for the three reasonable alternatives are LANL, Oak Ridge National Laboratory (ORNL), and Idaho National Engineering Laboratory (INEL). The analyses in this EIS indicate no significant difference in the potential environmental impacts among the alternatives. Each of the alternatives would use essentially the same technology for the production of the medical isotopes. Minor differences in environmental impacts among alternatives relate to the extent of activity necessary to modify and restart (as necessary) existing reactors and hot cell facilities at each of the sites, the quantities, of low-level radioactive waste generated, how such waste would be managed, and the length of time needed for initial and full production capacity

  9. Isotope separation process

    International Nuclear Information System (INIS)

    Lyon, R.K.

    1976-01-01

    The instant invention relates to a process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in said material. In one embodiment, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by selective dissociation of said excited molecules by the absorption of a single photon of visible or ultraviolet light. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium. 11 Claims, 2 Drawing Figures

  10. Natural isotopes abundance of 15N and 13C in leaves of some N2-fixing and non N2-fixing trees and shrubs in Syria

    International Nuclear Information System (INIS)

    Kurdali, F.; Al-Shamma'a, M.

    2007-12-01

    Variability in the natural abundance isotopes of 15 N and 13 C in leaves of several legume and non-legume plant species grown at different sites of two areas in semi-arid regions of Syria was determined. In the first area (non-saline soil), the 15 N values of a number of fixing and non-fixing reference plants ranged from -2.09 to +9.46, depending on plant species and studied site. 15 N in a number of legume species including Acacia cyanopylla (-1.73), Acacia farnesiana (-0.55), Prosopis juliflora (-1.64) and Medicago arborea (+1.6) were close to the atmospheric value pointing to a major contribution of N 2 fixing in these species; whereas, those of reference plants were highly positive (between +3.6 and +9.46%). In the actinorhizal tree, Elaeagnus angustifolia, the 15 N abundance was far lower (-0.46 to -2.1%) strongly suggesting that the plant obtained large proportional contribution from BNF. In contrast, δ 15 N values in some other legumes and actinorhizal plants were relatively similar to those of reference plants, suggesting that the contribution of fixed N 2 is negligible. On the other hand, δ 13 C% values in leaves of C3 plants were affected by plant species, ranging from a minimum of -28.67% to a maximum of -23%. However, they were the same within each plant species although they were grown at different sites. Moreover, dual stable isotope analysis in leaves of Prosopis juliflora and other non- legumes grown on a salt affected soil (second area) was also conducted. Results showed that salinity did not affect C assimilation in this woody legume since a higher carbon discrimination was obtained indicating that this plant is a salt tolerant species; whereas, N2-fixation was drastically affected (δ 15 N= +7.03). (Author)

  11. Archaeal and bacterial H-GDGTs are abundant in peat and their relative abundance is positively correlated with temperature

    Science.gov (United States)

    Naafs, B. D. A.; McCormick, D.; Inglis, G. N.; Pancost, R. D.; T-GRES Peat Database Collaborators

    2018-04-01

    Glycerol monoalkyl glycerol tetraether lipids (GMGTs; also called 'H-GDGTs') differ from the more commonly studied glycerol dialkyl glycerol tetraether (GDGTs) in that they have an additional covalent bond that links the two alkyl chains. Six different archaeal isoprenoidal H-GDGTs (H-isoGDGTs) and one branched H-GDGT (H-brGDGT), presumably produced by bacteria, have previously been found. However, the function of H-GDGTs in both domains of life is unknown. It is thought that the formation of this additional covalent bond results in enhanced membrane stability, accounting for the high abundance of H-GDGTs in extreme environments such as geothermal settings, but so far there has been little evidence to support this hypothesis. Here we report the distribution of H-GDGTs in a global peat database (n = 471) with a broad range in mean annual air temperature (MAAT) and pH. This is the first finding of H-GDGTs in soils (specifically, peat), highlighting that H-GDGTs are widespread in mesophilic settings. In addition, we report the presence of two new H-brGDGTs with one (H-1034) and two (H-1048) additional methyl groups, respectively. Our results suggest that the relative abundance of both bacterial and archaeal H-GDGTs compared to regular GDGTs is related to temperature with the highest relative abundance of H-GDGTs in tropical peats. Although other factors besides temperature likely also play a role, these results do support the hypothesis that H-GDGTs are an adaptation to temperature to maintain membrane stability. The observation that both bacterial and archaeal membrane lipids respond to temperature indicates the same adaption across the lipid divide between these two domains of life, suggesting parallel or convergent evolution (potentially facilitated by lateral gene transfer).

  12. Water Table Depth Reconstruction in Ombrotrophic Peatlands Using Biomarker Abundance Ratios and Compound-Specific Hydrogen Isotope Composition

    Science.gov (United States)

    Nichols, J. E.; Jackson, S. T.; Booth, R. K.; Pendall, E. G.; Huang, Y.

    2005-12-01

    Sediment cores from ombrotrophic peat bogs provide sensitive records of changes in precipitation/evaporation (P/E) balance. Various proxies have been developed to reconstruct surface moisture conditions in peat bogs, including testate amoebae, plant macrofossils, and peat humification. Studying species composition of testate amoeba assemblages is time consuming and requires specialized training. Humification index can be influenced by environmental factors other than moisture balance. The plant macrofossil proxy is less quantitative and cannot be performed on highly decomposed samples. We demonstrate that the ratio of C23 alkane to C29 alkane abundance may provide a simple alternative or complementary means of tracking peatland water-table depth. Data for this proxy can be collected quickly using a small sample (100 mg dry). Water-table depth decreases during drought, and abundance of Sphagnum, the dominant peat-forming genus, decreases as vascular plants increase. Sphagnum moss produces mainly medium chain-length alkanes (C21-C25) while vascular plants (grasses and shrubs) produce primarily longer chain-length alkanes (C27-C31). Therefore, C23:C29 n-alkane ratios quantitatively track the water table depth fluctuations in peat bogs. We compared C23:C29 n-alkane ratios in a core from Minden Bog (southeastern Michigan) with water table depth reconstructions based on testate-amoeba assemblages and humification. The 184-cm core spans the past ~3kyr of continuous peat deposition in the bog. Our results indicate that the alkane ratios closely track the water table depth variations, with C29 most abundant during droughts. We also explored the use of D/H ratios in Sphagnum biomarkers as a water-table depth proxy. Compound-specific hydrogen isotope ratio analyses were performed on Sphagnum biomarkers: C23 and C25 alkane and C24 acid. Dry periods are represented in these records by an enrichment of deuterium in these Sphagnum-specific compounds. These events also correlate

  13. Application of isotope hydrology related to limnological investigations in India

    International Nuclear Information System (INIS)

    Saravana Kumar, U.; Navada, S.V.

    2007-01-01

    Among the various hydrological environments, lakes are often well suited to investigate using isotopic tracers, environmental or injected. Lakes are systems, which although complex, are generally accessible to all points for sample collection, tracer injections and in-situ measurement. The various types of isotope applications in lake studies (limnology), reported in various literatures include; i) Lake dynamics investigations, interaction between lakes and adjacent water bodies (springs, river, groundwater etc) and the related water balance computations, ii) Lake sedimentation processes, iii) Gas exchange between lake water and the atmosphere, iv) Paleo-hydrologic and paleo-climatological problems etc. In this article, a few Indian case studies covering some of the above types of isotope applications in limnology are briefly summarized. (author)

  14. Distribution and relative abundance of the marine catfish (Siluriformes, Ariidae) in Sepetiba Bay, Rio de Janeiro

    OpenAIRE

    Azevedo, Márcia Cristina Costa de; Araújo, Francisco Gerson; Cruz Filho, Antônio Gomes da; Santos, Alexandre Clístenes de Alcântara

    1998-01-01

    Marine catfish (Ariidae) are abundant resources in otter trawl fisheries carried out at Sepetiba Bay, Rio de Janeiro (Lat. 22º54, 23º04'S; Long. 43º34 44º10'W). Relative abundance and distribution were assessed, based in 158 fishing sampling at seven sites in the Bay, between July-1993 e June-1996. Five species were recorded in the following abundance rank order: Genidens genidens (Valenciennes, 1839), Caihorops spixii (Agassiz,1829), Sciadeichthys lunisculis (Valenciennes, 1840), Nelunia bar...

  15. Ion-microprobe measurements of Mg, Ca, Ti and Fe isotopic ratios and trace element abundance in hibonite-bearing inclusions in primitive meteorites

    International Nuclear Information System (INIS)

    Fahey, A.J.

    1988-01-01

    This thesis reports the isotopic abundances of Mg, Ca, and Ti and rare earth element (REE) abundances in 19 hibonite-bearing inclusions from primative meteorites. The isotopic ratios of Fe were measured in one of the samples, Lance HH-1. These measurements were made by means of secondary ion mass spectrometry (CAMECA IMS-3f). The novel hardware and software developments that made this work possible are described in detail. The samples were studied in thin section in order to investigate the relationship between the inclusions and their mineralogical environments. Inclusions from a number of different meteorites, specifically, Mighei, Murray, Murchison, Lance, Efremovka, Vigarano, Qingzhen, Dhajala, and Semarkona, were studied. The isotopes of Ca and Ti show large and correlated abundance anomalies in their most neutron-rich isotopes, 48 Ca and 50 Ti. The largest anomalies among the samples studied here are in the Murray inclusion MY-F6, with a 4.6% deficit in 48 Ca and a 5.2% deficit in 50 Ti, and Lance HH-1, with 3.3% and 6.0% deficits in 48 Ca and 50 Ti respectively. Correlated excesses of 48 Ca and 50 Ti, up to 2.4% and 1.4% respectively, are found in some other samples studied here. The fact that there is a correlation of isotopic anomalies in two different elements is clear evidence for a nucleosynthetic origin of these effects. Various possibilities for the origin of these isotopic anomalies are discussed and it is shown that a Cosmic Chemical Memory-like model of the incomplete mixing of dust grains from one or several supernovae is sufficient to explain the data. Magnesium isotopes show excesses of 26 Mg, attributable to the in-situ decay of 26 Al, in 7 of these inclusions

  16. The relative abundance of desert tortoises on the Nevada Test Site within ecological landform units

    International Nuclear Information System (INIS)

    Woodward, R.; Rautenstrauch, K.R.; Hall, D.B.; Ostler, W.K.

    1998-09-01

    Sign-survey transects were sampled in 1996 to better determine the relative abundance of desert tortoises on the Nevada Test Site (NTS). These transects were sampled within ecological land-form units (ELUs), which are small, ecologically homogeneous units of land. Two-hundred and six ELUs were sampled by walking 332 transects totaling 889 kilometers (km). These ELUs covered 528 km 2 . Two-hundred and eight-one sign were counted. An average of 0.32 sign was found per km walked. Seventy percent of the area sampled had a very low abundance of tortoises, 29% had a low abundance, and 1% had a moderate abundance. A revised map of the relative abundance of desert tortoise on the NTS is presented. Within the 1,330 km 2 of desert tortoise habitat on the NTS, 49% is classified as having no tortoises or a very low abundance, 18% has a low or moderate abundance, 12% is unclassified land being used by the Yucca Mountain Site Characterization Project, and the remaining 21% still has an unknown abundance of desert tortoises. Based on the results of this work, the amount of tortoise habitat previously classified as having an unknown or low-moderate abundance, and on which clearance surveys and on-site monitoring was required, has been reduced by 20%

  17. s-Processing from MHD-induced mixing and isotopic abundances in presolar SiC grains

    Science.gov (United States)

    Palmerini, S.; Trippella, O.; Busso, M.; Vescovi, D.; Petrelli, M.; Zucchini, A.; Frondini, F.

    2018-01-01

    In the past years the observational evidence that s-process elements from Sr to Pb are produced by stars ascending the so-called Asymptotic Giant Branch (or "AGB") could not be explained by self-consistent models, forcing researchers to extensive parameterizations. The crucial point is to understand how protons can be injected from the envelope into the He-rich layers, yielding the formation of 13C and then the activation of the 13C (α,n)16O reaction. Only recently, attempts to solve this problem started to consider quantitatively physically-based mixing mechanisms. Among them, MHD processes in the plasma were suggested to yield mass transport through magnetic buoyancy. In this framework, we compare results of nucleosynthesis models for Low Mass AGB Stars (M≲ 3M⊙), developed from the MHD scenario, with the record of isotopic abundance ratios of s-elements in presolar SiC grains, which were shown to offer precise constraints on the 13C reservoir. We find that n-captures driven by magnetically-induced mixing can indeed account for the SiC data quite well and that this is due to the fact that our 13C distribution fulfils the above constraints rather accurately. We suggest that similar tests should be now performed using different physical models for mixing. Such comparisons would indeed improve decisively our understanding of the formation of the neutron source.

  18. Determination of the isotopic abundance of 235U in rocks in search for an Oklo phenomenon in Brazil by activation analysis

    International Nuclear Information System (INIS)

    Vasconcellos, M.B.A.; Armelin, M.J.A.; Lima, F.W. de; Fulfaro, R.

    1981-09-01

    Isotopic analyses of uranium are generally carried out by mass spectrometry, with a precision better than 1%. In nuclear laboratories it is often necessary to perform rapid determinations of 235 U isotopic abundances. Thermal neutron activation analysis by delayed neutron counting or by high resolution gamma-ray spectrometry can be applied for this purpose, although with less precision than by mass spectrometry. In this work, delayed neutron counting and gamma-ray spectrometry are used for the determination of the isotopic abundance of 235 U in rocks from the Northeastern region of Brazil. In the case of the application of delayed neutron counting, the rocks are analyzed non-destructively. When high resolution gamma-ray spectrometry is applied, a pre-irradiation chemical separation had to be performed, by extraction of uranium with tributylphosphate. By both methods employed the results for the isotopic abundance of 235 U can be considered as equal to the natural value of 0.702%, for the rocks under study. The precision attained by gamma-ray spectrometry is better than that by delayed neutron couting. (Author) [pt

  19. Fear or food - abundance of red fox in relation to occurrence of lynx and wolf.

    Science.gov (United States)

    Wikenros, Camilla; Aronsson, Malin; Liberg, Olof; Jarnemo, Anders; Hansson, Jessica; Wallgren, Märtha; Sand, Håkan; Bergström, Roger

    2017-08-22

    Apex predators may affect mesopredators through intraguild predation and/or supply of carrion from their prey, causing a trade-off between avoidance and attractiveness. We used wildlife triangle snow-tracking data to investigate the abundance of red fox (Vulpes vulpes) in relation to lynx (Lynx lynx) and wolf (Canis lupus) occurrence as well as land composition and vole (Microtus spp.) density. Data from the Swedish wolf-monitoring system and VHF/GPS-collared wolves were used to study the effect of wolf pack size and time since wolf territory establishment on fox abundance. Bottom-up processes were more influential than top-down effects as the proportion of arable land was the key indicator of fox abundance at the landscape level. At this spatial scale, there was no effect of wolf abundance on fox abundance, whereas lynx abundance had a positive effect. In contrast, at the wolf territory level there was a negative effect of wolves on fox abundance when including detailed information of pack size and time since territory establishment, whereas there was no effect of lynx abundance. This study shows that different apex predator species may affect mesopredator abundance in different ways and that the results may be dependent on the spatiotemporal scale and resolution of the data.

  20. Accurate experimental determination of the isotope effects on the triple point temperature of water. II. Combined dependence on the 18O and 17O abundances

    Science.gov (United States)

    Faghihi, V.; Kozicki, M.; Aerts-Bijma, A. T.; Jansen, H. G.; Spriensma, J. J.; Peruzzi, A.; Meijer, H. A. J.

    2015-12-01

    This paper is the second of two articles on the quantification of isotope effects on the triple point temperature of water. In this second article, we address the combined effects of 18O and 17O isotopes. We manufactured five triple point cells with waters with 18O and 17O abundances exceeding widely the natural abundance range while maintaining their natural 18O/17O relationship. The 2H isotopic abundance was kept close to that of VSMOW (Vienna Standard Mean Ocean Water). These cells realized triple point temperatures ranging between  -220 μK to 1420 μK with respect to the temperature realized by a triple point cell filled with VSMOW. Our experiment allowed us to determine an accurate and reliable value for the newly defined combined 18, 17O correction parameter of AO  =  630 μK with a combined uncertainty of 10 μK. To apply this correction, only the 18O abundance of the TPW needs to be known (and the water needs to be of natural origin). Using the results of our two articles, we recommend a correction equation along with the coefficient values for isotopic compositions differing from that of VSMOW and compare the effect of this new equation on a number of triple point cells from the literature and from our own institute. Using our correction equation, the uncertainty in the isotope correction for triple point cell waters used around the world will be  <1 μK.

  1. Determination of plutonium isotopic abundances by gamma-ray spectrometry. Interim report on the status of methods and techniques developed by the Lawrence Livermore Laboratory

    International Nuclear Information System (INIS)

    Gunnink, R.

    1980-03-01

    This report presents an overview of methods and techniques developed by the Lawrence Livermore Laboratory for determining plutonium isotopic abundances from gamma-ray spectra that have been measured with germanium detectors. The methodology of fitting the spectral features includes discussions of algorithms for gamma-ray and x-ray peak shape fitting and generation of response spectra profiles characteristic of specific isotopes. Applications of the techniques developed at government, commercial, and Japanese reprocessing plants are described. Current development of the methodology for the nondestructive analysis of samples containing nondescript solid materials is also presented

  2. Relative abundance and diel variation of zooplankton from south west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.; Peter, K.J.

    abundant group, of which calanoids predominated. A swarm of the hydromedusan species, Aequorea conica, (181/m sup(-3)) was seen at night. Quantitative and qualitative variations of various zooplankton groups from six stations in relation to selected physico...

  3. A novel method for collection of soil-emitted nitric oxide (NO) for natural abundance stable N isotope analysis

    Science.gov (United States)

    Yu, Z.; Elliott, E. M.

    2016-12-01

    The global inventory of NO emissions is poorly constrained with a large portion of the uncertainty attributed to soil NO emissions that result from soil abiotic and microbial processes. While natural abundance stable N isotopes (δ15N) in various soil N-containing compounds have proven to be a robust tracer of soil N cycling, soil δ15N-NO is rarely quantified mainly due to the diffuse nature, low concentrations, and high reactivity of soil-emitted NO. Here, we present the development and application of a dynamic flux chamber system capable of simultaneously measuring soil NO fluxes and collecting NO for δ15N-NO measurements. The system couples a widely used flow-through soil chamber with a NO collection train, in which NO can be converted to NO2 through O3 titration in a Teflon reaction coil, followed by NO2 collection in a 20% triethanolamine (TEA) solution as nitrite and nitrate for δ15N analysis using the denitrifier method. The efficiency of NO-NO2 conversion in the reaction coil and the recovery of NO in the TEA solution were determined experimentally and found to be quantitative (>99%) over a 10 to 749 ppbv NO mixing ratio range. An analytical NO tank (δ15N-NO=71.0±0.4‰) was used to calibrate the method for δ15N-NO analysis. The resulting accuracy and precision (1σ) of the method across various environmental conditions were 1.6‰ and 1.2‰, respectively. Using this new method, controlled laboratory incubations have been conducted to characterize NO emissions induced by rewetting of air-dried surface soil sampled from an urban forest. Pulsed NO emissions, up to 30 times higher than maximum soil NO emissions under steady state, were triggered upon the rewetting and lasted for next 36 hours. While the measured δ15N-NO over the course of the NO pulsing ranged from -52.0‰ and -34.6‰, reinforcing the notion that soil δ15N-NO is lower than those of fossil-fuel combustion sources, a transient δ15N-NO shift was captured immediately after the

  4. The effects of oxides of carbon and nitrogen emissions on the isotope and element abundances in foliage of C3 plants

    International Nuclear Information System (INIS)

    Sucgang, Raymond; Pabroa, Preciosa Corazon; Petrache, Cristina; Bulanhagui, Jaika Faye; Legaspi, Charmaine; Niegas, Elaine; Enerva, Lorna; Luces, Arnicole

    2014-01-01

    The carbon and nitrogen stable isotope abundance of C3 plants mango (Magnifera indica L), molave (Vitex parviflora Juss), talisay (Terminalia catappa L.) leaves harvested from sites with ambient air conditions and sites receiving air pollution contributions from coal-fired power plants were determined and compared. Isotope Ratio Mass Spectroscopy, IRMS was used to determine 13 C and 15 N in the samples. The elemental composition of the samples was determined using Inductively Coupled Plasma-Atomic Emission Spectrometry, ICP-AES. The 13 C of the leaves grown in ambient air were found to fall within the range of -25.0 to -22.0 per mill and a close agreement with the literature values for the natural abundance of 13 C in C3 plants (-27.0 to -21.0 per mill). The 13 C abundance of plants obtained from sites polluted by coal-fired plants were sporadic from -35 to 24.0 per mille. The 15 N abundance in leaves grown under ambient air condition (-1.0 to 2.0 per mille) were way below the 15 N abundance of plants from coal-fired plant-polluted regions (16.0 to 17.5 per mille). Elemental exposition indicated no differences in element concentrations in leaves from ambient and polluted sites. Differences exist in the Ca, Mg, K ratios across species and are affected by seasonal variation. (author)

  5. The isotopic abundance ratio 12C/13C in the solar atmosphere determined from CH-lines in the photospheric spectrum

    International Nuclear Information System (INIS)

    Iversen, Oe.

    1976-01-01

    The R-branch of the (0,0) vibrational band of the violet electronic transition A 2 Δ-X 2 PI of CH is analysed. Isotope wavelength shifts were measured on laboratory spectrograms. The method of synthesising the spectrum was used, and the molecular dissociation equilibrium through the photosphere was computed. 13 CH is not definitely identified in the photospheric spectrum and only upper limits of the 13 C abundance are deduced. The upper limits are sensitive to the local continuum level. A photospheric abundance ratio 12 C/ 13 C greater than the terrestrial value of 90 seems highly probable. (Auth.)

  6. A thoroughly validated spreadsheet for calculating isotopic abundances (H-2, O-17, O-18) for mixtures of waters with different isotopic compositions

    NARCIS (Netherlands)

    Faghihi, V.; Meijer, H. A. J.; Groening, Manfred

    2015-01-01

    RationaleOxygen and hydrogen stable isotopes are widely used tracers for studies on naturally occurring and laboratory mixtures of isotopically different waters. Although the mixing calculations are straightforward to perform, there are ample possibilities to make mistakes, especially when dealing

  7. Long-Term Changes in Species Composition and Relative Abundances of Sharks at a Provisioning Site

    OpenAIRE

    Brunnschweiler, Juerg M.; Abrantes, Kátya G.; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-...

  8. Does osmotic distillation change the isotopic relation of wines?

    Directory of Open Access Journals (Sweden)

    Schmitt Matthias

    2014-01-01

    Full Text Available Currently partial alcohol reduction of wine is in the focus of research worldwide. There are several technologies available to achieve this target. These techniques are either based on distilling or membrane processes. Osmotic distillation, one of the possibilities, is a quite modern membrane process that can be used. During that process, wine is pumped in counter flow to water along a micro porous, hydrophobic membrane. The volatile components of the wine can permeate that membrane and are dissolved in water. The driving force of that process is the vapor pressure difference between the volatiles on the wine and water side of the membrane. The aim of this work was to determine if the alcohol reduction by osmotic distillation can change the isotopic relation in a wine. Can this enological practice change the composition of a wine in a way that an illegal water addition is simulated? Different wines were reduced by 2% alcohol v/v with varying process parameters. The isotopic analysis of the O 16/18 ratio in the wine were performed according to the OIV methods (353/2009 These analyses showed that the isotopic ratio is modified by an alcohol reduction of 2% v/v in a way that corresponds to an addition of 4–5% of external water.

  9. Relative Abundance of Integral Plasma Membrane Proteins in Arabidopsis Leaf and Root Tissue Determined by Metabolic Labeling and Mass Spectrometry

    Science.gov (United States)

    Bernfur, Katja; Larsson, Olaf; Larsson, Christer; Gustavsson, Niklas

    2013-01-01

    Metabolic labeling of proteins with a stable isotope (15N) in intact Arabidopsis plants was used for accurate determination by mass spectrometry of differences in protein abundance between plasma membranes isolated from leaves and roots. In total, 703 proteins were identified, of which 188 were predicted to be integral membrane proteins. Major classes were transporters, receptors, proteins involved in membrane trafficking and cell wall-related proteins. Forty-one of the integral proteins, including nine of the 13 isoforms of the PIP (plasma membrane intrinsic protein) aquaporin subfamily, could be identified by peptides unique to these proteins, which made it possible to determine their relative abundance in leaf and root tissue. In addition, peptides shared between isoforms gave information on the proportions of these isoforms. A comparison between our data for protein levels and corresponding data for mRNA levels in the widely used database Genevestigator showed an agreement for only about two thirds of the proteins. By contrast, localization data available in the literature for 21 of the 41 proteins show a much better agreement with our data, in particular data based on immunostaining of proteins and GUS-staining of promoter activity. Thus, although mRNA levels may provide a useful approximation for protein levels, detection and quantification of isoform-specific peptides by proteomics should generate the most reliable data for the proteome. PMID:23990937

  10. Isotope separation process

    International Nuclear Information System (INIS)

    1976-01-01

    The invention relates to a process for separating a given material into two or more parts, in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in the said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase UF 6 by infrared photon absorption followed by selective reaction of said excited UF 6 with atomic chlorine, bromine, or iodine to form a product which may be separated by means known in the art

  11. Relative abundance of mesopredators and size of oak patches in the cross-timbers ecoregion

    Science.gov (United States)

    Disney, M.R.; Hellgren, E.C.; Davis, C.A.; Leslie, David M.; Engle, David M.

    2008-01-01

    Mesopredators (e.g., raccoon Procyon lotor, Virginia opossum Didelphis virginiana, striped skunk Mephitis mephitis) have received considerable attention because of links to population declines in birds via increased nest predation, especially in landscapes fragmented by anthropogenic forces. Relationships of abundance of mesopredators to size of habitat patches have received less attention than relationships to other metrics of fragmentation, particularly edge characteristics. We tested the hypothesis that relative abundance of mesopredators (e.g., raccoons and Virginia opossums) was related negatively to size of forest patch. We delineated 15 patches of oak (Quercus) forest ranging from 0.2 to 55.3 ha within a grassland-woodland mosaic in the cross-timbers ecoregion of Oklahoma. Scent stations and live traps within these patches were used to index relative abundance of mesopredators in summers 2003 and 2004. Both indices of relative abundance were related weakly and negatively to area of forest patch. However, rate of capture and visitation to scent station were not correlated consistently throughout the study. Our results suggested that the two methods to index abundance provided separate information on functional and numerical responses to size of patch. Our evidence that mesopredators within the cross timbers were more likely to be in smaller patches of oak forest may have implications to success of avian nesting in these patches.

  12. Isotope separation method and apparatus

    International Nuclear Information System (INIS)

    Lyon, R.K.; Eisner, P.N.; Thomas, W.R.L.

    1980-01-01

    A method and apparatus are specified for separating a mixture of isotopes present in a compound, preferably a gaseous compound, into two or more parts in each of which the abundances of the isotopes differ from the natural abundances of the isotopes in the compound. The invention particularly relates to carrying out a laser induced, isotopically selective conversion of gaseous molecules in such a manner as to achieve more than one stage of isotope separation along the length of the laser beam. As an example, the invention is applied to the separation of the isotopes of uranium in UF 6 , in which either the U-235 or U-238 isotope is selectively excited by means of irradiation from an infrared laser, and the selectively excited isotope converted into a product that can be recovered from UF 6 by one of a variety of methods that are described. (U.K.)

  13. [Mammals' camera-trapping in Sierra Nanchititla, Mexico: relative abundance and activity patterns].

    Science.gov (United States)

    Monroy-Vilchis, Octavio; Zarco-González, Martha M; Rodríguez-Soto, Clarita; Soria-Díaz, Leroy; Urios, Vicente

    2011-03-01

    Species conservation and their management depend on the availability of their population behavior and changes in time. This way, population studies include aspects such as species abundance and activity pattern, among others, with the advantage that nowadays new technologies can be applied, in addition to common methods. In this study, we used camera-traps to obtain the index of relative abundance and to establish activity pattern of medium and large mammals in Sierra Nanchititla, Mexico. The study was conducted from December 2003 to May 2006, with a total sampling effort of 4 305 trap-days. We obtained 897 photographs of 19 different species. Nasua narica, Sylvilagus floridanus and Urocyon cinereoargenteus were the most abundant, in agreement with the relative abundance index (RAI, number of independent records/100 trap-days), and according to previous studies with indirect methods in the area. The activity patterns of the species showed that 67% of them are nocturnal, except Odocoileus virginianus, Nasua narica and others. Some species showed differences with previously reported patterns, which are related with seasonality, resources availability, organism sex, principally. The applied method contributed with reliable data about relative abundance and activity patterns.

  14. Using SPIRAL (Single Pollen Isotope Ratio AnaLysis) to estimate C 3- and C 4-grass abundance in the paleorecord

    Science.gov (United States)

    Nelson, David M.; Hu, Feng Sheng; Scholes, Daniel R.; Joshi, Neeraj; Pearson, Ann

    2008-05-01

    C 3 and C 4 grasses differ greatly in their responses to environmental controls and influences on biogeochemical processes (e.g. water, carbon, and nutrient cycling). Difficulties in distinguishing between these two functional groups of grasses have hindered paleoecological studies of grass-dominated ecosystems. Stable carbon isotopic analysis of individual grains of grass pollen using a spooling-wire microcombustion device interfaced with an isotope-ratio mass spectrometer holds promise for improving C 3 and C 4 grass reconstructions. This technique, SPIRAL (Single Pollen Isotope Ratio AnaLysis), has only been evaluated using pollen of known C 3 and C 4 grasses. To test the ability of SPIRAL to reproduce the abundance of C 3 and C 4 grasses on the landscape, we measured δ13C values of > 1500 individual grains of grass pollen isolated from the surface sediments of ten lakes in areas that span a large gradient of C 3- and C 4-grass abundance, as determined from vegetation surveys. Results indicate a strong positive correlation between the δ13C-based estimates of % C 4-grass pollen and the abundance of C 4 grasses on the landscape. The % C 4-grass pollen slightly underestimates the actual abundance of C 4 grasses at sites with high proportions of C 4 grasses, which can be corrected using regression analysis. Comparison of the % C 4-grass pollen with C/N and δ13C measurements of bulk organic matter illustrates the distinct advantages of grass-pollen δ13C as a proxy for distinguishing C 3 and C 4 shifts within the grass family. Thus SPIRAL promises to advance our understanding of grassland ecology and evolution.

  15. Sex ratios, mating frequencies and relative abundance of sympatric millipedes in the genus Chersastus (Diplopoda: Pachybolidae

    Directory of Open Access Journals (Sweden)

    Mark Ian Cooper

    2014-12-01

    Full Text Available Three hypotheses exist for explaining climbing behavior in millipedes: 1 waterlogging, 2 detritus limiting, and 3 mate avoidance. Data of sex ratios, mating frequency and relative abundance are provided to suggest an alternative explanation for the pattern in sympatric forest millipedes. Sex ratio differences - from equality - were tested using a G-test comparing millipedes on and above ground. Mating frequencies were calculated based on the percentage of paired individuals. Relative abundance may correlate with male-biases in the sex ratios. All three factors suggest Chersastus inscriptus has a higher reproductive potential than C. anulatus. This is evidence for mating hotspots.

  16. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    Science.gov (United States)

    Brunnschweiler, Juerg M; Abrantes, Kátya G; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion among shark

  17. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    Directory of Open Access Journals (Sweden)

    Juerg M Brunnschweiler

    Full Text Available Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive

  18. The relative importance of water temperature and residence time in predicting cyanobacteria abundance in regulated rivers.

    Science.gov (United States)

    Cha, YoonKyung; Cho, Kyung Hwa; Lee, Hyuk; Kang, Taegu; Kim, Joon Ha

    2017-11-01

    Despite a growing awareness of the problems associated with cyanobacterial blooms in rivers, and particularly in regulated rivers, the drivers of bloom formation and abundance in rivers are not well understood. We developed a Bayesian hierarchical model to assess the relative importance of predictors of summer cyanobacteria abundance, and to test whether the relative importance of each predictor varies by site, using monitoring data from 16 sites in the four major rivers of South Korea. The results suggested that temperature and residence time, but not nutrient levels, are important predictors of summer cyanobacteria abundance in rivers. Although the two predictors were of similar significance across the sites, the residence time was marginally better in accounting for the variation in cyanobacteria abundance. The model with spatial hierarchy demonstrated that temperature played a consistently significant role at all sites, and showed no effect from site-specific factors. In contrast, the importance of residence time varied significantly from site to site. This variation was shown to depend on the trophic state, indicated by the chlorophyll-a and total phosphorus levels. Our results also suggested that the magnitude of weir inflow is a key factor determining the cyanobacteria abundance under baseline conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Relative abundance and size of coastal sharks derived from commercial shark longline catch and effort data.

    Science.gov (United States)

    Carlson, J K; Hale, L F; Morgan, A; Burgess, G

    2012-04-01

    In the north-west Atlantic Ocean, stock assessments conducted for some commercially harvested coastal sharks indicate declines from 64 to 80% with respect to virgin population levels. While the status of commercially important species is available, abundance trend information for other coastal shark species in the north-west Atlantic Ocean are unavailable. Using a generalized linear modelling (GLM) approach, a relative abundance index was derived from 1994 to 2009 using observer data collected in a commercial bottom longline fishery. Trends in abundance and average size were estimated for bull shark Carcharhinus leucas, spinner shark Carcharhinus brevipinna, tiger shark Galeocerdo cuvier and lemon shark Negaprion brevirostris. Increases in relative abundance for all shark species ranged from 14% for C. brevipinna, 12% for C. leucas, 6% for N. brevirostris and 3% for G. cuvier. There was no significant change in the size at capture over the time period considered for all species. While the status of shark populations should not be based exclusively on abundance trend information, but ultimately on stock assessment models, results from this study provide some cause for optimism on the status of these coastal shark species. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

  20. Possibility of determination of the Galaxy age by the method of uranium - thorium isotopic relations

    International Nuclear Information System (INIS)

    Lyutostanskij, Yu.S.; Malevannyj, S.V.; Panov, I.V.; Chechetkin, V.M.

    1988-01-01

    Calculations concerning the formation of heavy elements in an astrophysical fast nuclear process characteristics of the Supernova explosions are carried out in the kinetic model of nucleosynthesis. The age of the Galaxy T G has been calculated making use of the method of uranium-thorium isotopic relations supplemented with the data on 244 Pu abundance in meteorites. T G is shown to be strongly dependent upon the calculation method applied to production of nuclei in r process, upon the data on neutron-rich nuclei and as well upon the external conditions, i.e. the density and temperature in the explosing star. The possibility of nucleosynthesis takes place due to close Supernova explosion, which enriched the chemical content of earth matter with heavy elements is analyzed. The range of allowed values of parameters of the theory of nucleosynthesis is studied

  1. Multidirectional abundance shifts among North American birds and the relative influence of multifaceted climate factors.

    Science.gov (United States)

    Huang, Qiongyu; Sauer, John R; Dubayah, Ralph O

    2017-09-01

    Shifts in species distributions are major fingerprint of climate change. Examining changes in species abundance structures at a continental scale enables robust evaluation of climate change influences, but few studies have conducted these evaluations due to limited data and methodological constraints. In this study, we estimate temporal changes in abundance from North American Breeding Bird Survey data at the scale of physiographic strata to examine the relative influence of different components of climatic factors and evaluate the hypothesis that shifting species distributions are multidirectional in resident bird species in North America. We quantify the direction and velocity of the abundance shifts of 57 permanent resident birds over 44 years using a centroid analysis. For species with significant abundance shifts in the centroid analysis, we conduct a more intensive correlative analysis to identify climate components most strongly associated with composite change of abundance within strata. Our analysis focus on two contrasts: the relative importance of climate extremes vs. averages, and of temperature vs. precipitation in strength of association with abundance change. Our study shows that 36 species had significant abundance shifts over the study period. The average velocity of the centroid is 5.89 km·yr -1 . The shifted distance on average covers 259 km, 9% of range extent. Our results strongly suggest that the climate change fingerprint in studied avian distributions is multidirectional. Among 6 directions with significant abundance shifts, the northwestward shift was observed in the largest number of species (n = 13). The temperature/average climate model consistently has greater predictive ability than the precipitation/extreme climate model in explaining strata-level abundance change. Our study shows heterogeneous avian responses to recent environmental changes. It highlights needs for more species-specific approaches to examine contributing

  2. Are leaf physiological traits related to leaf water isotopic enrichment in restinga woody species?

    Directory of Open Access Journals (Sweden)

    BRUNO H.P. ROSADO

    2013-09-01

    Full Text Available During plant-transpiration, water molecules having the lighter stable isotopes of oxygen and hydrogen evaporate and diffuse at a faster rate through the stomata than molecules having the heavier isotopes, which cause isotopic enrichment of leaf water. Although previous models have assumed that leaf water is well-mixed and isotopically uniform, non-uniform stomatal closure, promoting different enrichments between cells, and different pools of water within leaves, due to morpho-physiological traits, might lead to inaccuracies in isotopic models predicting leaf water enrichment. We evaluate the role of leaf morpho-physiological traits on leaf water isotopic enrichment in woody species occurring in a coastal vegetation of Brazil known as restinga. Hydrogen and oxygen stable isotope values of soil, plant stem and leaf water and leaf traits were measured in six species from restinga vegetation during a drought and a wet period. Leaf water isotopic enrichment relative to stem water was more homogeneous among species during the drought in contrast to the wet period suggesting convergent responses to deal to temporal heterogeneity in water availability. Average leaf water isotopic enrichment relative to stem water during the drought period was highly correlated with relative apoplastic water content. We discuss this observation in the context of current models of leaf water isotopic enrichment as a function of the Péclet effect. We suggest that future studies should include relative apoplastic water content in isotopic models.

  3. Are leaf physiological traits related to leaf water isotopic enrichment in restinga woody species?

    Science.gov (United States)

    Rosado, Bruno H P; De Mattos, Eduardo A; Sternberg, Leonel Da S L

    2013-09-01

    During plant-transpiration, water molecules having the lighter stable isotopes of oxygen and hydrogen evaporate and diffuse at a faster rate through the stomata than molecules having the heavier isotopes, which cause isotopic enrichment of leaf water. Although previous models have assumed that leaf water is well-mixed and isotopically uniform, non-uniform stomatal closure, promoting different enrichments between cells, and different pools of water within leaves, due to morpho-physiological traits, might lead to inaccuracies in isotopic models predicting leaf water enrichment. We evaluate the role of leaf morpho-physiological traits on leaf water isotopic enrichment in woody species occurring in a coastal vegetation of Brazil known as restinga. Hydrogen and oxygen stable isotope values of soil, plant stem and leaf water and leaf traits were measured in six species from restinga vegetation during a drought and a wet period. Leaf water isotopic enrichment relative to stem water was more homogeneous among species during the drought in contrast to the wet period suggesting convergent responses to deal to temporal heterogeneity in water availability. Average leaf water isotopic enrichment relative to stem water during the drought period was highly correlated with relative apoplastic water content. We discuss this observation in the context of current models of leaf water isotopic enrichment as a function of the Péclet effect. We suggest that future studies should include relative apoplastic water content in isotopic models.

  4. Isotopic abundance analysis of carbon, nitrogen and sulfur with a combined elemental analyzer-mass spectrometer system

    International Nuclear Information System (INIS)

    Pichlmayer, F.; Blochberger, K.

    1988-01-01

    Stable isotope ratio measurements of carbon, nitrogen and sulfur are of growing interest as analytical tool in many fields of research, but applications were somewhat hindered in the past by the fact that cumbersome sample preparation was necessary. A method has therefore been developed, consisting in essential of coupling an elemental analyzer with an isotope mass spectrometer, enabling fast and reliable conversion of C-, N- and S-compounds in any solid or liquid sample into the measuring gases carbon dioxide, nitrogen and sulfur dioxide for on-line isotopic analysis. The experimental set-up and the main characteristics are described in short and examples of application in environmental research, food analysis and clinical diagnosis are given. (orig.)

  5. Standard test method for isotopic abundance analysis of uranium hexafluoride and uranyl nitrate solutions by multi-collector, inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2014-01-01

    1.1 This test method covers the isotopic abundance analysis of 234U, 235U, 236U and 238U in samples of hydrolysed uranium hexafluoride (UF6) by inductively coupled plasma source, multicollector, mass spectrometry (ICP-MC-MS). The method applies to material with 235U abundance in the range of 0.2 to 6 % mass. This test method is also described in ASTM STP 1344. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  6. Weed management practices affect the diversity and relative abundance of physic nut mites.

    Science.gov (United States)

    Saraiva, Althiéris de Sousa; Sarmento, Renato A; Erasmo, Eduardo A L; Pedro-Neto, Marçal; de Souza, Danival José; Teodoro, Adenir V; Silva, Daniella G

    2015-03-01

    Crop management practices determine weed community, which in turn may influence patterns of diversity and abundance of associated arthropods. This study aimed to evaluate whether local weed management practices influence the diversity and relative abundance of phytophagous and predatory mites, as well as mites with undefined feeding habits--of the families Oribatidae and Acaridae--in a physic nut (Jatropha curcas L.) plantation subjected to (1) within-row herbicide spraying and between-row mowing; (2) within-row herbicide spraying and no between-row mowing; (3) within-row weeding and between-row mowing; (4) within-row weeding and no between-row mowing; and (5) unmanaged (control). The herbicide used was glyphosate. Herbicide treatments resulted in higher diversity and relative abundance of predatory mites and mites with undefined feeding habit on physic nut shrubs. This was probably due to the toxic effects of the herbicide on mites or to removal of weeds. Within-row herbicide spraying combined with between-row mowing was the treatment that most contributed to this effect. Our results show that within-row weeds harbor important species of predatory mites and mites with undefined feeding habit. However, the dynamics of such mites in the system can be changed according to the weed management practice applied. Among the predatory mites of the family Phytoseiidae Amblydromalus sp. was the most abundant, whereas Brevipalpus phoenicis was the most frequent phytophagous mite and an unidentified oribatid species was the most frequent mite with undefined feeding habit.

  7. High-precision optical measurements of 13C/12C isotope ratios in organic compounds at natural abundance

    Science.gov (United States)

    Zare, Richard N.; Kuramoto, Douglas S.; Haase, Christa; Tan, Sze M.; Crosson, Eric R.; Saad, Nabil M. R.

    2009-01-01

    A continuous-flow cavity ring-down spectroscopy (CRDS) system integrating a chromatographic separation technique, a catalytic combustor, and an isotopic 13C/12C optical analyzer is described for the isotopic analysis of a mixture of organic compounds. A demonstration of its potential is made for the geochemically important class of short-chain hydrocarbons. The system proved to be linear over a 3-fold injection volume dynamic range with an average precision of 0.95‰ and 0.67‰ for ethane and propane, respectively. The calibrated accuracy for methane, ethane, and propane is within 3‰ of the values determined using isotope ratio mass spectrometry (IRMS), which is the current method of choice for compound-specific isotope analysis. With anticipated improvements, the low-cost, portable, and easy-to-use CRDS-based instrumental setup is poised to evolve into a credible challenge to the high-cost and complex IRMS-based technique. PMID:19564619

  8. Correlation and Stacking of Relative Paleointensity and Oxygen Isotope Data

    Science.gov (United States)

    Lurcock, P. C.; Channell, J. E.; Lee, D.

    2012-12-01

    The transformation of a depth-series into a time-series is routinely implemented in the geological sciences. This transformation often involves correlation of a depth-series to an astronomically calibrated time-series. Eyeball tie-points with linear interpolation are still regularly used, although these have the disadvantages of being non-repeatable and not based on firm correlation criteria. Two automated correlation methods are compared: the simulated annealing algorithm (Huybers and Wunsch, 2004) and the Match protocol (Lisiecki and Lisiecki, 2002). Simulated annealing seeks to minimize energy (cross-correlation) as "temperature" is slowly decreased. The Match protocol divides records into intervals, applies penalty functions that constrain accumulation rates, and minimizes the sum of the squares of the differences between two series while maintaining the data sequence in each series. Paired relative paleointensity (RPI) and oxygen isotope records, such as those from IODP Site U1308 and/or reference stacks such as LR04 and PISO, are warped using known warping functions, and then the un-warped and warped time-series are correlated to evaluate the efficiency of the correlation methods. Correlations are performed in tandem to simultaneously optimize RPI and oxygen isotope data. Noise spectra are introduced at differing levels to determine correlation efficiency as noise levels change. A third potential method, known as dynamic time warping, involves minimizing the sum of distances between correlated point pairs across the whole series. A "cost matrix" between the two series is analyzed to find a least-cost path through the matrix. This least-cost path is used to nonlinearly map the time/depth of one record onto the depth/time of another. Dynamic time warping can be expanded to more than two dimensions and used to stack multiple time-series. This procedure can improve on arithmetic stacks, which often lose coherent high-frequency content during the stacking process.

  9. Diversity and relative abundance of the bacterial pathogen, Flavobacterium spp., infecting reproductive ecotypes of kokanee salmon.

    Science.gov (United States)

    Lemay, Matthew A; Russello, Michael A

    2014-11-04

    Understanding the distribution and abundance of pathogens can provide insight into the evolution and ecology of their host species. Previous research in kokanee, the freshwater form of sockeye salmon (Oncorhynchus nerka), found evidence that populations spawning in streams may experience a greater pathogen load compared with populations that spawn on beaches. In this study we tested for differences in the abundance and diversity of the gram-negative bacteria, Flavobacterium spp., infecting tissues of kokanee in both of these spawning habitats (streams and beaches). Molecular assays were carried out using primers designed to amplify a ~200 nucleotide region of the gene encoding the ATP synthase alpha subunit (AtpA) within the genus Flavobacterium. Using a combination of DNA sequencing and quantitative PCR (qPCR) we compared the diversity and relative abundance of Flavobacterium AtpA amplicons present in DNA extracted from tissue samples of kokanee collected from each spawning habitat. We identified 10 Flavobacterium AtpA haplotypes among the tissues of stream-spawning kokanee and seven haplotypes among the tissues of beach-spawning kokanee, with only two haplotypes shared between spawning habitats. Haplotypes occurring in the same clade as F. psychrophilum were the most prevalent (92% of all reads, 60% of all haplotypes), and occurred in kokanee from both spawning habitats (streams and beaches). Subsequent qPCR assays did not find any significant difference in the relative abundance of Flavobacterium AtpA amplicons between samples from the different spawning habitats. We confirmed the presence of Flavobacterium spp. in both spawning habitats and found weak evidence for increased Flavobacterium diversity in kokanee sampled from stream-spawning sites. However, the quantity of Flavobacterium DNA did not differ between spawning habitats. We recommend further study aimed at quantifying pathogen diversity and abundance in population-level samples of kokanee combined with

  10. Weed-Species Abundance and Diversity Indices in Relation to Tillage Systems and Fertilization

    Directory of Open Access Journals (Sweden)

    Ilias S. Travlos

    2018-04-01

    Full Text Available Weeds pose a major threat to world agriculture by reducing detrimentally crop yield and quality. However, at the same time, weeds are major interacting components of the agroecosystems. Abundance and diversity of weeds vary significantly among the several communities. In order to evaluate each community's structure and the interactions among them, several population indices are used as key tools. In parallel, various cultivation and land management strategies, such as tillage and fertilization, are commonly used in terms of integrated weed management. Estimating the response of weed species on those practices is crucial for both biodiversity maintenance and alternative weed control methods. Many experiments have confirmed the fundamental role of tillage intensity and nutrition supply in weed species' abundance and diversity. For instance, in some studies, the abundance of perennial weeds was doubled under reduced tillage intensity. In addition, higher values of Shannon-Weiner and Pielou indices were reported in the PK fertilization treatment compared to the control and NK fertilization treatments. The objective of this paper is to provide a brief overview of the key results of these experiments and summarize the part of the literature related to the effect of tillage systems and fertilization on weed species abundance and diversity. Such knowledge could contribute to the sound design and implementation of integrated weed management programs which in turn may lead to a decrease in the density of serious and noxious weeds and an increase in the overall balance of agroecosystems.

  11. Modeled distribution and abundance of a pelagic seabird reveal trends in relation to fisheries

    Science.gov (United States)

    Renner, Martin; Parrish, Julia K.; Piatt, John F.; Kuletz, Kathy J.; Edwards, Ann E.; Hunt, George L.

    2013-01-01

    The northern fulmar Fulmarus glacialis is one of the most visible and widespread seabirds in the eastern Bering Sea and Aleutian Islands. However, relatively little is known about its abundance, trends, or the factors that shape its distribution. We used a long-term pelagic dataset to model changes in fulmar at-sea distribution and abundance since the mid-1970s. We used an ensemble model, based on a weighted average of generalized additive model (GAM), multivariate adaptive regression splines (MARS), and random forest models to estimate the pelagic distribution and density of fulmars in the waters of the Aleutian Archipelago and Bering Sea. The most important predictor variables were colony effect, sea surface temperature, distribution of fisheries, location, and primary productivity. We calculated a time series from the ratio of observed to predicted values and found that fulmar at-sea abundance declined from the 1970s to the 2000s at a rate of 0.83% (± 0.39% SE) per annum. Interpolating fulmar densities on a spatial grid through time, we found that the center of fulmar distribution in the Bering Sea has shifted north, coinciding with a northward shift in fish catches and a warming ocean. Our study shows that fisheries are an important, but not the only factor, shaping fulmar distribution and abundance trends in the eastern Bering Sea and Aleutian Islands.

  12. Study of the Role of Terrestrial Processes in the Carbon Cycle Based on Measurements of the Abundance and Isotopic Composition of Atmospheric CO2

    Energy Technology Data Exchange (ETDEWEB)

    Piper, Stephen C; Keeling, Ralph F

    2012-01-03

    The main objective of this project was to continue research to develop carbon cycle relationships related to the land biosphere based on remote measurements of atmospheric CO2 concentration and its isotopic ratios 13C/12C, 18O/16O, and 14C/12C. The project continued time-series observations of atmospheric carbon dioxide and isotopic composition begun by Charles D. Keeling at remote sites, including Mauna Loa, the South Pole, and eight other sites. Using models of varying complexity, the concentration and isotopic measurements were used to study long-term change in the interhemispheric gradients in CO2 and 13C/12C to assess the magnitude and evolution of the northern terrestrial carbon sink, to study the increase in amplitude of the seasonal cycle of CO2, to use isotopic data to refine constraints on large scale changes in isotopic fractionation which may be related to changes in stomatal conductance, and to motivate improvements in terrestrial carbon cycle models. The original proposal called for a continuation of the new time series of 14C measurements but subsequent descoping to meet budgetary constraints required termination of measurements in 2007.

  13. Nature's starships. I. Observed abundances and relative frequencies of amino acids in meteorites

    International Nuclear Information System (INIS)

    Cobb, Alyssa K.; Pudritz, Ralph E.

    2014-01-01

    The class of meteorites called carbonaceous chondrites are examples of material from the solar system which have been relatively unchanged from the time of their initial formation. These meteorites have been classified according to the temperatures and physical conditions of their parent planetesimals. We collate available data on amino acid abundance in these meteorites and plot the concentrations of different amino acids for each meteorite within various meteorite subclasses. We plot average concentrations for various amino acids across meteorites separated by subclass and petrologic type. We see a predominance in the abundance and variety of amino acids in CM2 and CR2 meteorites. The range in temperature corresponding to these subclasses indicates high degrees of aqueous alteration, suggesting aqueous synthesis of amino acids. Within the CM2 and CR2 subclasses, we identify trends in relative frequencies of amino acids to investigate how common amino acids are as a function of their chemical complexity. These two trends (total abundance and relative frequencies) can be used to constrain formation parameters of amino acids within planetesimals. Our organization of the data supports an onion shell model for the temperature structure of planetesimals. The least altered meteorites (type 3) and their amino acids originated near cooler surface regions. The most active amino acid synthesis likely took place at intermediate depths (type 2). The most altered materials (type 1) originated furthest toward parent body cores. This region is likely too hot to either favor amino acid synthesis or for amino acids to be retained after synthesis.

  14. Medical Isotopes Production Project: Molybdenum-99 and related isotopes - environmental impact statement. Volume II, comment response document

    International Nuclear Information System (INIS)

    1996-04-01

    This Environmental Impact Statement (EIS) provides environmental and technical information concerning the U.S. Department of Energy's (DOE) proposal to establish a domestic source to produce molybdenum-99 (Mo-99) and related isotopes (iodine-131, xenon-133, and iodine-125). Mo-99, a radioactive isotope of the element molybdenum, decays to form metastable technetium-99 (Tc-99m), a radioactive isotope used thousands of times daily in medical diagnostic procedures in the U.S. Currently, all Mo-99 used in the U.S. is obtained from a single Canadian source. DOE is pursuing the Medical Isotopes Production Project in order to ensure that a reliable supply of Mo-99 is available to the U.S. medical community as soon as practicable. Under DOE's preferred alternative, the Chemistry and Metallurgy Research Facility at the Los Alamos National Laboratory (LANL) and the Annular Core Research Reactor and Hot Cell Facility at Sandia National Laboratories/New Mexico (SNL/NM) would be used for production of the medical isotopes. In addition, three other reasonable alternatives and a No Action alternative are analyzed in detail, The sites for these three reasonable alternatives are LANL, Oak Ridge National Laboratory (ORNL), and Idaho National Engineering Laboratory (INEL). The analyses in this EIS indicate no significant difference in the potential environmental impacts among the alternatives. Each of the alternatives would use essentially the same technology for the production of the medical isotopes. Minor differences in environmental impacts among alternatives relate to the extent of activity necessary to modify and restart (as necessary) existing reactors and hot cell facilities at each of the sites, the quantities of low-level radioactive waste generated, how such waste would be managed, and the length of time needed for initial and full production capacity. This document contains comments recieved from meetings held regarding the site selection for isotope production

  15. Abundance and Isotopic Composition of Gases in the Martian Atmosphere: First Results from the Mars Curiosity Rover

    Science.gov (United States)

    Mahaffy, Paul; Webster, Chris R.; Atreya, Sushil K.; Franz, Heather; Wong, Michael; Conrad, Pamela G.; Harpold, Dan; Jones, John J.; Leshin, Laurie, A.; Manning, Heidi; hide

    2013-01-01

    Repeated measurements of the composition of the Mars atmosphere from Curiosity Rover yield a (40)Ar/N2 ratio 1.7 times greater and the (40)Ar/(36)Ar ratio 1.6 times smaller than the Viking Lander values in 1976. The unexpected change in (40)Ar/N2 ratio probably results from different instrument characteristics although we cannot yet rule out some unknown atmospheric process. The new (40)Ar/(36)Ar ratio is more aligned with Martian meteoritic values. Besides Ar and N2 the Sample Analysis at Mars instrument suite on the Curiosity Rover has measured the other principal components of the atmosphere and the isotopes. The resulting volume mixing ratios are: CO2 0.960(+/- 0.007); (40)Ar 0.0193(+/- 0.0001); N2 0.0189(+/- 0.0003); O2 1.45(+/- 0.09) x 10(exp -3); and CO 5.45(+/- 3.62) x 10(exp 4); and the isotopes (40)Ar/(36)Ar 1.9(+/- 0.3) x 10(exp 3), and delta (13)C and delta (18)O from CO2 that are both several tens of per mil more positive than the terrestrial averages. Heavy isotope enrichments support the hypothesis of large atmospheric loss. Moreover, the data are consistent with values measured in Martian meteorites, providing additional strong support for a Martian origin for these rocks.

  16. Calcium Isotope Analysis by Mass Spectrometry

    Science.gov (United States)

    Boulyga, S.; Richter, S.

    2010-12-01

    The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. This presentation discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. Additionally, the availability of Ca isotope reference materials will be discussed.

  17. Fluorescent peptide biosensor for probing the relative abundance of cyclin-dependent kinases in living cells.

    Directory of Open Access Journals (Sweden)

    Laetitia Kurzawa

    Full Text Available Cyclin-dependant kinases play a central role in coordinating cell growth and division, and in sustaining proliferation of cancer cells, thereby constituting attractive pharmacological targets. However, there are no direct means of assessing their relative abundance in living cells, current approaches being limited to antigenic and proteomic analysis of fixed cells. In order to probe the relative abundance of these kinases directly in living cells, we have developed a fluorescent peptide biosensor with biligand affinity for CDKs and cyclins in vitro, that retains endogenous CDK/cyclin complexes from cell extracts, and that bears an environmentally-sensitive probe, whose fluorescence increases in a sensitive fashion upon recognition of its targets. CDKSENS was introduced into living cells, through complexation with the cell-penetrating carrier CADY2 and applied to assess the relative abundance of CDK/Cyclins through fluorescence imaging and ratiometric quantification. This peptide biosensor technology affords direct and sensitive readout of CDK/cyclin complex levels, and reports on differences in complex formation when tampering with a single CDK or cyclin. CDKSENS further allows for detection of differences between different healthy and cancer cell lines, thereby enabling to distinguish cells that express high levels of these heterodimeric kinases, from cells that present decreased or defective assemblies. This fluorescent biosensor technology provides information on the overall status of CDK/Cyclin complexes which cannot be obtained through antigenic detection of individual subunits, in a non-invasive fashion which does not require cell fixation or extraction procedures. As such it provides promising perspectives for monitoring the response to therapeutics that affect CDK/Cyclin abundance, for cell-based drug discovery strategies and fluorescence-based cancer diagnostics.

  18. A Metastable Equilibrium Model for the Relative Abundances of Microbial Phyla in a Hot Spring

    Science.gov (United States)

    Dick, Jeffrey M.; Shock, Everett L.

    2013-01-01

    Many studies link the compositions of microbial communities to their environments, but the energetics of organism-specific biomass synthesis as a function of geochemical variables have rarely been assessed. We describe a thermodynamic model that integrates geochemical and metagenomic data for biofilms sampled at five sites along a thermal and chemical gradient in the outflow channel of the hot spring known as “Bison Pool” in Yellowstone National Park. The relative abundances of major phyla in individual communities sampled along the outflow channel are modeled by computing metastable equilibrium among model proteins with amino acid compositions derived from metagenomic sequences. Geochemical conditions are represented by temperature and activities of basis species, including pH and oxidation-reduction potential quantified as the activity of dissolved hydrogen. By adjusting the activity of hydrogen, the model can be tuned to closely approximate the relative abundances of the phyla observed in the community profiles generated from BLAST assignments. The findings reveal an inverse relationship between the energy demand to form the proteins at equal thermodynamic activities and the abundance of phyla in the community. The distance from metastable equilibrium of the communities, assessed using an equation derived from energetic considerations that is also consistent with the information-theoretic entropy change, decreases along the outflow channel. Specific divergences from metastable equilibrium, such as an underprediction of the relative abundances of phototrophic organisms at lower temperatures, can be explained by considering additional sources of energy and/or differences in growth efficiency. Although the metabolisms used by many members of these communities are driven by chemical disequilibria, the results support the possibility that higher-level patterns of chemotrophic microbial ecosystems are shaped by metastable equilibrium states that depend on both the

  19. Hydrogen and carbon isotopes of petroleum and related organic matter

    International Nuclear Information System (INIS)

    Yeh, H.W.; Epstein, S.

    1981-01-01

    D/H and 13 C/ 12 C ratios were measured for 114 petroleum samples and for several samples of related organic matter. DeltaD of crude oil ranges from -85 to -181 per thousand except for one distillate (-250 per thousand) from the Kenai gas field; delta 13 C of crude oil ranges from -23.3 to -32.5 per thousand. Variation in deltaD and delta 13 C values of compound-grouped fractions of a crude oil is small, 3 and 1.1 per thousand, respectively, and the difference in deltaD and delta 13 C between oil and coeval wax is slight. Gas fractions are 53 to 70 and 22.6 to 23.2 per thousand depleted in D and 13 C, respectively, relative to the coexisting oil fractions. The deltaD and delta 13 C values of the crude oils appear to be largely determined by the isotopic compositions of their organic precursors. The contribution of terrestrial organic debris to the organic precursors of most marine crude oils may be significant. (author)

  20. Abundance, stable isotopic composition, and export fluxes of DOC, POC, and DIC from the Lower Mississippi River during 2006–2008

    Science.gov (United States)

    Cai, Yihua; Guo, Laodong; Wang, Xuri; Aiken, George R.

    2015-01-01

    Sources, abundance, isotopic compositions, and export fluxes of dissolved inorganic carbon (DIC), dissolved and colloidal organic carbon (DOC and COC), and particulate organic carbon (POC), and their response to hydrologic regimes were examined through monthly sampling from the Lower Mississippi River during 2006–2008. DIC was the most abundant carbon species, followed by POC and DOC. Concentration and δ13C of DIC decreased with increasing river discharge, while those of DOC remained fairly stable. COC comprised 61 ± 3% of the bulk DOC with similar δ13C abundances but higher percentages of hydrophobic organic acids than DOC, suggesting its aromatic and diagenetically younger status. POC showed peak concentrations during medium flooding events and at the rising limb of large flooding events. While δ13C-POC increased, δ15N of particulate nitrogen decreased with increasing discharge. Overall, the differences in δ13C between DOC or DIC and POC show an inverse correlation with river discharge. The higher input of soil organic matter and respired CO2 during wet seasons was likely the main driver for the convergence of δ13C between DIC and DOC or POC, whereas enhanced in situ primary production and respiration during dry seasons might be responsible for their isotopic divergence. Carbon export fluxes from the Mississippi River were estimated to be 13.6 Tg C yr−1 for DIC, 1.88 Tg C yr−1 for DOC, and 2.30 Tg C yr−1 for POC during 2006–2008. The discharge-normalized DIC yield decreased during wet seasons, while those of POC and DOC increased and remained constant, respectively, implying variable responses in carbon export to the increasing discharge.

  1. Parametric scaling from species relative abundances to absolute abundances in the computation of biological diversity: a first proposal using Shannon's entropy.

    Science.gov (United States)

    Ricotta, Carlo

    2003-01-01

    Traditional diversity measures such as the Shannon entropy are generally computed from the species' relative abundance vector of a given community to the exclusion of species' absolute abundances. In this paper, I first mention some examples where the total information content associated with a given community may be more adequate than Shannon's average information content for a better understanding of ecosystem functioning. Next, I propose a parametric measure of statistical information that contains both Shannon's entropy and total information content as special cases of this more general function.

  2. Allergen relative abundance in several wheat varieties as revealed via a targeted quantitative approach using MS.

    Science.gov (United States)

    Rogniaux, Hélène; Pavlovic, Marija; Lupi, Roberta; Lollier, Virginie; Joint, Mathilde; Mameri, Hamza; Denery, Sandra; Larré, Colette

    2015-05-01

    Food allergy has become a major health issue in developed countries, therefore there is an urgent need to develop analytical methods able to detect and quantify with a good sensitivity and reliability some specific allergens in complex food matrices. In this paper, we present a targeted MS/MS approach to compare the relative abundance of the major recognized wheat allergens in the salt-soluble (albumin/globulin) fraction of wheat grains. Twelve allergens were quantified in seven wheat varieties, selected from three Triticum species: T. aestivum (bread wheat), T. durum (durum wheat), and T. monococcum. The allergens were monitored from one or two proteotypic peptides and their relative abundance was deduced from the intensity of one fragment measured in MS/MS. Whereas the abundance of some of the targeted allergens was quite stable across the genotypes, others like alpha-amylase inhibitors showed clear differences according to the wheat species, in accordance with the results of earlier functional studies. This study enriches the scarce knowledge available on allergens content in wheat genotypes, and brings new perspectives for food safety and plant breeding. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Relative Abundance of Proteins in Blood Plasma Samples from Patients with Chronic Cerebral Ischemia.

    Science.gov (United States)

    Kaysheva, Anna L; Kopylov, Artur T; Ponomarenko, Elena A; Kiseleva, Olga I; Teryaeva, Nadezhda B; Potapov, Alexander A; Izotov, Alexander А; Morozov, Sergei G; Kudryavtseva, Valeria Yu; Archakov, Alexander I

    2018-03-01

    A comparative protein profile analysis of 17 blood plasma samples from patients with ischemia and 20 samples from healthy volunteers was carried out using ultra-high resolution mass spectrometry. The analysis of measurements was performed using the proteomics search engine OMSSA. Normalized spectrum abundance factor (NSAF) in the biological samples was assessed using SearchGUI. The findings of mass spectrometry analysis of the protein composition of blood plasma samples demonstrate that the depleted samples are quite similar in protein composition and relative abundance of proteins. By comparing them with the control samples, we have found a small group of 44 proteins characteristic of the blood plasma samples from patients with chronic cerebral ischemia. These proteins contribute to the processes of homeostasis maintenance, including innate immune response unfolding, the response of a body to stress, and contribution to the blood clotting cascade.

  4. The relative contribution of climate to changes in lesser prairie-chicken abundance

    Science.gov (United States)

    Ross, Beth E.; Haukos, David A.; Hagen, Christian A.; Pitman, James

    2016-01-01

    Managing for species using current weather patterns fails to incorporate the uncertainty associated with future climatic conditions; without incorporating potential changes in climate into conservation strategies, management and conservation efforts may fall short or waste valuable resources. Understanding the effects of climate change on species in the Great Plains of North America is especially important, as this region is projected to experience an increased magnitude of climate change. Of particular ecological and conservation interest is the lesser prairie-chicken (Tympanuchus pallidicinctus), which was listed as “threatened” under the U.S. Endangered Species Act in May 2014. We used Bayesian hierarchical models to quantify the effects of extreme climatic events (extreme values of the Palmer Drought Severity Index [PDSI]) relative to intermediate (changes in El Niño Southern Oscillation) and long-term climate variability (changes in the Pacific Decadal Oscillation) on trends in lesser prairie-chicken abundance from 1981 to 2014. Our results indicate that lesser prairie-chicken abundance on leks responded to environmental conditions of the year previous by positively responding to wet springs (high PDSI) and negatively to years with hot, dry summers (low PDSI), but had little response to variation in the El Niño Southern Oscillation and the Pacific Decadal Oscillation. Additionally, greater variation in abundance on leks was explained by variation in site relative to broad-scale climatic indices. Consequently, lesser prairie-chicken abundance on leks in Kansas is more strongly influenced by extreme drought events during summer than other climatic conditions, which may have negative consequences for the population as drought conditions intensify throughout the Great Plains.

  5. Species richness and relative abundance of birds in natural and anthropogenic fragments of Brazilian Atlantic forest

    Directory of Open Access Journals (Sweden)

    Luiz dos Anjos

    2004-06-01

    Full Text Available Bird communities were studied in two types of fragmented habitat of Atlantic forest in the State of Paraná, southern Brazil; one consisted of forest fragments that were created as a result of human activities (forest remnants, the other consisted of a set of naturally occurring forest fragments (forest patches. Using quantitative data obtained by the point counts method in 3 forest patches and 3 forest remnants during one year, species richness and relative abundance were compared in those habitats, considering species groups according to their general feeding habits. Insectivores, omnivores, and frugivores presented similar general tendencies in both habitats (decrease of species number with decreasing size and increasing isolation of forest fragment. However, these tendencies were different, when considering the relative abundance data: the trunk insectivores presented the highest value in the smallest patch while the lowest relative abundance was in the smallest remnant. In the naturally fragmented landscape, time permitted that the loss of some species of trunk insectivores be compensated for the increase in abundance of other species. In contrast, the remnants essentially represented newly formed islands that are not yet at equilibrium and where future species losses would make them similar to the patches.Comunidades de aves foram estudadas em duas regiões fragmentadas de floresta Atlântica no Estado do Paraná, sul do Brasil; uma região é constituída de fragmentos florestais que foram criados como resultado de atividades humanas (remanescentes florestais e a outra de um conjunto de fragmentos florestais naturais (manchas de floresta. Usando dados quantitativos (o método de contagens pontuais previamente obtidos em 3 manchas de floresta e em 3 remanescentes florestais durante um ano, a riqueza e a abundância relativa de aves foram comparadas naqueles habitats considerando as espécies pelos seus hábitos alimentares. Inset

  6. Zircon (Hf, O isotopes) as melt indicator: Melt infiltration and abundant new zircon growth within melt rich layers of granulite-facies lenses versus solid-state recrystallization in hosting amphibolite-facies gneisses (central Erzgebirge, Bohemian Massif)

    Science.gov (United States)

    Tichomirowa, Marion; Whitehouse, Martin; Gerdes, Axel; Schulz, Bernhard

    2018-03-01

    In the central Erzgebirge within the Bohemian Massif, lenses of high pressure and ultrahigh pressure felsic granulites occur within meta-sedimentary and meta-igneous amphibolite-facies felsic rocks. In the felsic granulite, melt rich parts and restite form alternating layers, and were identified by petrology and bulk rock geochemistry. Mineral assemblages representing the peak P-T conditions were best preserved in melanocratic restite layers. In contrast, in the melt rich leucocratic layers, garnet and related HP minerals as kyanite are almost completely resorbed. Both layers display differences in accessory minerals: melanosomes have frequent and large monazite and Fe-Ti-minerals but lack xenotime and apatite; leucosomes have abundant apatite and xenotime while monazite is rare. Here we present a detailed petrographic study of zircon grains (abundance, size, morphology, inclusions) in granulite-facies and amphibolite-facies felsic gneisses, along with their oxygen and hafnium isotope compositions. Our data complement earlier Usbnd Pb ages and trace element data (REE, Y, Hf, U) on zircons from the same rocks (Tichomirowa et al., 2005). Our results show that the degree of melting determines the behaviour of zircon in different layers of the granulites and associated amphibolite-facies rocks. In restite layers of the granulite lenses, small, inherited, and resorbed zircon grains are preserved and new zircon formation is very limited. In contrast, new zircons abundantly grew in the melt rich leucocratic layers. In these layers, the new zircons (Usbnd Pb age, trace elements, Hf, O isotopes) best preserve the information on peak metamorphic conditions due to intense corrosion of other metamorphic minerals. The new zircons often contain inherited cores. Compared to cores, the new zircons and rims show similar or slightly lower Hf isotope values, slightly higher Hf model ages, and decreased oxygen isotope ratios. The isotope compositions (Hf, O) of new zircons indicate

  7. Isotope separation process

    International Nuclear Information System (INIS)

    Lyon, R.K.

    1977-01-01

    The instant invention relates to a process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by a step wherein more of the excited molecules than nonexcited molecules are converted to a chemically different form which may be separated by means known in the art. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium. 15 claims, 1 figure

  8. Isotope separation process

    International Nuclear Information System (INIS)

    Thomas, W.R.L.

    1979-01-01

    The instant invention relates to an improved process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same element in said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by a step wherein more of the excited molecules than non-excited molecules are converted to a chemically different form which may be separated by means known in the art. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium

  9. 235Uranium isotope abundance certified reference material for gamma spectrometry EC nuclear reference material 171 certification report

    International Nuclear Information System (INIS)

    De Bievre, P.; Eschbach, H.L.; Lesser, R.; Meyer, H.; Audenhove, Van J.

    1986-01-01

    This certification report contains the information necessary for the final certification of EC nuclear reference material 171. It is also intended to inform the user of the reference material concerned on technical/scientific details which are not given in the certificate. The report describes the reference material which consists of sets of U 3 O 8 samples with five different 235 U/U abundances, filled in cylindrical aluminium cans. The can bottom serves as window for emitted gamma radiation. The report describes how the 235 U/U abundances were characterized, how the other properties relevant for gamma measurements were determined and gives all connected results as well as those from the verification measurements. Appendix A represents the draft certificate. 32 refs

  10. Relative abundance estimations of Chengal trees in a tropical rainforest by using modified canopy fractional cover (mCFC)

    International Nuclear Information System (INIS)

    Hassan, N

    2014-01-01

    Tree species composition estimations are important to sustain forest management. This study estimates relative abundance of useful timber tree species (chengal) using Hyperion EO-1 satellite data. For the estimation, modified Canopy Fractional Cover (mCFC) was developed using Canopy Fractional Cover (CFC). mCFC was more sensitive to estimate relative abundance of chengal trees rather than Mixture Tuned Matched Filtering (MTMF). Meanwhile, MTMF was more sensitive to estimate the relative abundance of undisturbed forest. Accuracy suggests that the mCFC model is better to explain relative abundance of chengal trees than MTMF. Therefore, it can be concluded that relative abundance of tree species extracted from Hyperion EO-1 satellite data using modified Canopy Fractional Cover is an obtrusive approach used for identifying tree species composition

  11. Relative abundance estimations of chengal tree in a tropical rainforest by using modified Canopy Fractional Cover (mCFC)

    International Nuclear Information System (INIS)

    Hassan, N

    2014-01-01

    Tree species composition estimations are important to sustain forest management. This study challenged estimates of relative abundance of useful timber tree species (chengal) using Hyperion EO-1 satellite data. For the estimation, modified Canopy Fractional Cover (mCFC) was developed using Canopy Fractional Cover (CFC). mCFC was more sensitive to estimate relative abundance of chengal trees rather than Mixture Tuned Matched Filtering (MTMF). Meanwhile, MTMF was more sensitive to estimate the relative abundance of undisturbed forest. Accuracy suggests that the mCFC model is better to explain relative abundance of chengal trees than MTMF. Therefore, it can be concluded that relative abundance of trees species extracted from Hyperion EO-1 satellite data using modified Canopy Fractional Cover is an obtrusive approach used for identifying trees species composition

  12. Size matters: abundance matching, galaxy sizes, and the Tully-Fisher relation in EAGLE

    Science.gov (United States)

    Ferrero, Ismael; Navarro, Julio F.; Abadi, Mario G.; Sales, Laura V.; Bower, Richard G.; Crain, Robert A.; Frenk, Carlos S.; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2017-02-01

    The Tully-Fisher relation (TFR) links the stellar mass of a disc galaxy, Mstr, to its rotation speed: it is well approximated by a power law, shows little scatter, and evolves weakly with redshift. The relation has been interpreted as reflecting the mass-velocity scaling (M ∝ V3) of dark matter haloes, but this interpretation has been called into question by abundance-matching (AM) models, which predict the galaxy-halo mass relation to deviate substantially from a single power law and to evolve rapidly with redshift. We study the TFR of luminous spirals and its relation to AM using the EAGLE set of Λ cold dark matter (ΛCDM) cosmological simulations. Matching both relations requires disc sizes to satisfy constraints given by the concentration of haloes and their response to galaxy assembly. EAGLE galaxies approximately match these constraints and show a tight mass-velocity scaling that compares favourably with the observed TFR. The TFR is degenerate to changes in galaxy formation efficiency and the mass-size relation; simulations that fail to match the galaxy stellar mass function may fit the observed TFR if galaxies follow a different mass-size relation. The small scatter in the simulated TFR results because, at fixed halo mass, galaxy mass and rotation speed correlate strongly, scattering galaxies along the main relation. EAGLE galaxies evolve with lookback time following approximately the prescriptions of AM models and the observed mass-size relation of bright spirals, leading to a weak TFR evolution consistent with observation out to z = 1. ΛCDM models that match both the abundance and size of galaxies as a function of stellar mass have no difficulty reproducing the observed TFR and its evolution.

  13. Emission spectrometric isotope analyzer

    International Nuclear Information System (INIS)

    Mauersberger, K.; Meier, G.; Nitschke, W.; Rose, W.; Schmidt, G.; Rahm, N.; Andrae, G.; Krieg, D.; Kuefner, W.; Tamme, G.; Wichlacz, D.

    1982-01-01

    An emission spectrometric isotope analyzer has been designed for determining relative abundances of stable isotopes in gaseous samples in discharge tubes, in liquid samples, and in flowing gaseous samples. It consists of a high-frequency generator, a device for defined positioning of discharge tubes, a grating monochromator with oscillating slit and signal converter, signal generator, window discriminator, AND connection, read-out display, oscillograph, gas dosing device and chemical conversion system with carrier gas source and vacuum pump

  14. READSCAN: A fast and scalable pathogen discovery program with accurate genome relative abundance estimation

    KAUST Repository

    Naeem, Raeece

    2012-11-28

    Summary: READSCAN is a highly scalable parallel program to identify non-host sequences (of potential pathogen origin) and estimate their genome relative abundance in high-throughput sequence datasets. READSCAN accurately classified human and viral sequences on a 20.1 million reads simulated dataset in <27 min using a small Beowulf compute cluster with 16 nodes (Supplementary Material). Availability: http://cbrc.kaust.edu.sa/readscan Contact: or raeece.naeem@gmail.com Supplementary information: Supplementary data are available at Bioinformatics online. 2012 The Author(s).

  15. READSCAN: A fast and scalable pathogen discovery program with accurate genome relative abundance estimation

    KAUST Repository

    Naeem, Raeece; Rashid, Mamoon; Pain, Arnab

    2012-01-01

    Summary: READSCAN is a highly scalable parallel program to identify non-host sequences (of potential pathogen origin) and estimate their genome relative abundance in high-throughput sequence datasets. READSCAN accurately classified human and viral sequences on a 20.1 million reads simulated dataset in <27 min using a small Beowulf compute cluster with 16 nodes (Supplementary Material). Availability: http://cbrc.kaust.edu.sa/readscan Contact: or raeece.naeem@gmail.com Supplementary information: Supplementary data are available at Bioinformatics online. 2012 The Author(s).

  16. Fear or food ? abundance of red fox in relation to occurrence of lynx and wolf

    OpenAIRE

    Wikenros, Camilla; Aronsson, Malin; Liberg, Olof; Jarnemo, Anders; Hansson, Jessica; Wallgren, M?rtha; Sand, H?kan; Bergstr?m, Roger

    2017-01-01

    Apex predators may affect mesopredators through intraguild predation and/or supply of carrion from their prey, causing a trade-off between avoidance and attractiveness. We used wildlife triangle snow-tracking data to investigate the abundance of red fox (Vulpes vulpes) in relation to lynx (Lynx lynx) and wolf (Canis lupus) occurrence as well as land composition and vole (Microtus spp.)?density. Data from the Swedish wolf-monitoring system and VHF/GPS-collared wolves were used to study the eff...

  17. Carbon-13 isotopic abundance and concentration of atmospheric methane for background air in the Southern and Northern Hemispheres from 1978 to 1989

    International Nuclear Information System (INIS)

    Stevens, C.M.; Sepanski; Morris, L.J.

    1995-03-01

    Atmospheric methane (CH 4 ) may become an increasingly important contributor to global warming in future years. Its atmospheric concentration has risen, doubling over the past several hundred years, and additional methane is thought to have a much greater effect on climate, on a per molecule basis, than additional C0 2 at present day concentrations (Shine et al. 1990). The causes of the increase of atmospheric CH 4 have been difficult to ascertain because of a lack of quantitative knowledge of the fluxes (i.e., net emissions) from the numerous anthropogenic and natural sources. The goal of CH 4 isotopic studies is to provide a constraint (and so reduce the uncertainties) in estimating the relative fluxes from the various isotopically distinct sources, whose combined fluxes must result in the measured atmospheric isotopic composition, after the fractionating effect of the atmospheric removal process is considered. In addition, knowledge of the spatial and temporal changes in the isotopic composition of atmospheric CH 4 , along with estimates of the fluxes from some of the major sources, makes it possible to calculate growth rates for sources whose temporal emissions trends would be difficult to measure directly

  18. Incorporating breeding abundance into spatial assignments on continuous surfaces.

    Science.gov (United States)

    Rushing, Clark S; Marra, Peter P; Studds, Colin E

    2017-06-01

    Determining the geographic connections between breeding and nonbreeding populations, termed migratory connectivity, is critical to advancing our understanding of the ecology and conservation of migratory species. Assignment models based on stable isotopes historically have been an important tool for studying migratory connectivity of small-bodied species, but the low resolution of these assignments has generated interest into combining isotopes with other sources in information. Abundance is one of the most appealing data sources to include in isotope-based assignments, but there are currently no statistical methods or guidelines for optimizing the contribution of stable isotopes and abundance for inferring migratory connectivity. Using known-origin stable-hydrogen isotope samples of six Neotropical migratory bird species, we rigorously assessed the performance of assignment models that differentially weight the contribution of the isotope and abundance data. For two species with adequate sample sizes, we used Pareto optimality to determine the set of models that simultaneously minimized both assignment error rate and assignment area. We then assessed the ability of the top models from these two species to improve assignments of the remaining four species compared to assignments based on isotopes alone. We show that the increased precision of models that include abundance is often offset by a large increase in assignment error. However, models that optimally weigh the abundance data relative to the isotope data can result in higher precision and, in some cases, lower error than models based on isotopes alone. The top models, however, depended on the distribution of relative breeding abundance, with patchier distributions requiring stronger downweighting of abundance, and we present general guidelines for future studies. These results confirm that breeding abundance can be an important source of information for studies investigating broad-scale movements of

  19. Earthworm eco-physiological characteristics and quantification of earthworm feeding in vermifiltration system for sewage sludge stabilization using stable isotopic natural abundance

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaowei; Xing, Meiyan, E-mail: lixiaowei419@163.com; Yang, Jian; Dai, Xiaohu

    2014-07-15

    Highlights: • Earthworm growth biomass and activity decreased with the VF depth. • Earthworm gut microbial communities were dominated by Gammaproteobacteria. • δ{sup 15}N and δ{sup 13}C in earthworms decreased with time, and increased with the VF depth. • Effect of earthworm feeding in enhanced VSS reduction was analyzed quantitatively. • Earthworm feeding had low contribution to the enhanced VSS reduction. - Abstract: Previous studies showed that the presence of earthworm improves treatment performance of vermifilter (VF) for sewage sludge stabilization, but earthworm eco-physiological characteristics and effects in VF were not fully investigated. In this study, earthworm population, enzymatic activity, gut microbial community and stable isotopic abundance were investigated in the VF. Results showed that biomass, average weight, number and alkaline phosphatase activity of the earthworms tended to decrease, while protein content and activities of peroxidase and catalase had an increasing tendency as the VF depth. Earthworm gut microbial communities were dominated by Gammaproteobacteria, and the percentages arrived to 76–92% of the microbial species detected. {sup 15}N and {sup 13}C natural abundance of the earthworms decreased with operation time, and increased as the VF depth. Quantitative analysis using δ{sup 15}N showed that earthworm feeding and earthworm–microorganism interaction were responsible for approximately 21% and 79%, respectively, of the enhanced volatile suspended solid reduction due to the presence of earthworm. The finding provides a quantitative insight into how earthworms influence on sewage sludge stabilization in vermifiltration system.

  20. Abundance of thraustochytridsand bacteria in the equatorial Indian Ocean, in relation totransparent exopolymeric particles (TEPs)

    Digital Repository Service at National Institute of Oceanography (India)

    Damare, V.; Raghukumar, S.

    Thraustochytrid protists are often abundant in coastal waters. However, their population dynamics and substrate preferences in the oceanic water column are poorly understood.We studied the abundance and distribution of thraustochytrids, bacteria...

  1. Seasonal abundance of soil arthropods in relation to meteorological and edaphic factors in the agroecosystems of Faisalabad, Punjab, Pakistan.

    Science.gov (United States)

    Shakir, Muhammad Mussadiq; Ahmed, Sohail

    2015-05-01

    Soil arthropods are an important component of agroecosystems, contributing significantly to their biodiversity and functioning. However, seasonal patterns, population dynamics, and significant roles of these soil arthropods in improvement of soil structures and functions are influenced by many factors. The objective of the current study was to investigate soil arthropod abundance in relation to a blend of meteorological and edaphic factors and to find out the difference in abundance among various crops (sugarcane, cotton, wheat, alfalfa fodder, and citrus orchards). The arthropod sampling was done by pitfall traps and Tullgren extractions on fortnightly intervals. Soil temperature and relative humidity were noted on the field sites while analysis for soil pH, organic matter, and soil moisture contents were done in the laboratory. The rainfall data was obtained from an observatory. Results showed that significant differences were found in soil arthropod abundance across different sampling months and crops. Out of total 13,673 soil arthropods sampled, 38 % belonged to Collembola, followed by 15 % Hymenoptera, 15 % Acarina, 11 % Myriapods, 6 % Coleoptera, 5 % Orthoptera, and 5 % Araneae. Mean abundance per sample was highest in summer months as compared to winter. Overall abundance per sample was significantly different between all crops (p arthropods according to abundance, i.e., highly abundant (Collembola, Acarina, Myripoda, Hymenoptera), moderately abundant (Orthoptera, Aranae, Coleoptera), least abundant (Dermaptera, Hemiptera, Diptera), and rare (Blattaria, Isoptera, Diplura, Lepidoptera). Soil temperature and soil organic matter showed significant positive correlation with abundance, while relative humidity was significantly negatively correlated. Soil moisture and soil pH showed no significant correlations while no correlation was found with total rainfall. PCA analysis revealed that soil surface arthropods were the major contributors of variation in overall

  2. Gray whale distribution relative to benthic invertebrate biomass and abundance: Northeastern Chukchi Sea 2009-2012

    Science.gov (United States)

    Brower, Amelia A.; Ferguson, Megan C.; Schonberg, Susan V.; Jewett, Stephen C.; Clarke, Janet T.

    2017-10-01

    The shallow continental shelf waters of the Bering and Chukchi seas are the northernmost foraging grounds of North Pacific gray whales (Eschrichtius robustus). Benthic amphipods are considered the primary prey of gray whales in these waters, although no comprehensive quantitative analysis has been performed to support this assumption. Gray whale relative abundance, distribution, and behavior in the northeastern Chukchi Sea (69°-72°N, 155-169°W) were documented during aerial surveys in June-October 2009-2012. Concurrently, vessel-based benthic infaunal sampling was conducted in the area in July-August 2009-10, September 2011, and August 2012. Gray whales were seen in the study area each month that surveys were conducted, with the majority of whales feeding. Statistical analyses confirm that the highest densities of feeding gray whales were associated with high benthic amphipod abundance, primarily within 70 km of shore from Point Barrow to Icy Cape, in water whales were not seen in 40-km×40-km cells containing benthic sampling stations with 85 m-2 or fewer amphipods. Continuing broad-scale aerial surveys in the Chukchi Sea and prey sampling near feeding gray whales will be an important means to monitor and document ongoing and predicted ecosystem changes.

  3. Relative abundance and species richness of cerambycid beetles in partial cut and uncut bottomland hardwood forests

    Science.gov (United States)

    Newell, P.; King, S.

    2009-01-01

    Partial cutting techniques are increasingly advocated and used to create habitat for priority wildlife. However, partial cutting may or may not benefit species dependent on deadwood; harvesting can supplement coarse woody debris in the form of logging slash, but standing dead trees may be targeted for removal. We sampled cerambycid beetles during the spring and summer of 2006 and 2007 with canopy malaise traps in 1- and 2-year-old partial cut and uncut bottomland hardwood forests of Louisiana. We captured a total of 4195 cerambycid beetles representing 65 species. Relative abundance was higher in recent partial cuts than in uncut controls and with more dead trees in a plot. Total species richness and species composition were not different between treatments. The results suggest partial cuts with logging slash left on site increase the abundance of cerambycid beetles in the first few years after partial cutting and that both partial cuts and uncut forest should be included in the bottomland hardwood forest landscape.

  4. Influence of culture medium composition on relative mRNA abundances in domestic cat embryos.

    Science.gov (United States)

    Hribal, R; Jewgenow, K; Braun, B C; Comizzoli, P

    2013-04-01

    Different culture conditions have been used to produce domestic cat embryos. As part of the in vitro procedures, the medium composition significantly affects the quality of the embryo development also. Quality assessments based on cleavage kinetics and blastomere symmetry are useful, but embryos also can differ in their relative gene expression patterns despite similar morphological characteristics. The aim of this study was to compare cat embryos produced with two different in vitro culture systems routinely used in two different laboratories [Smithsonian Conservation Biology Institute, Washington D.C., USA (SCBI) and Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany (IZW)]. Specifically, relative mRNA expression patterns of critical genes for pre-implantation embryo development were assessed in both conditions. Embryos were produced in parallel in both culture systems by IVF using frozen-thawed ejaculated semen in the United States and fresh epididymal sperm in Germany. Success of embryo development in vitro was recorded as well as relative mRNA abundances [DNA methyltransferases 1 and 3A (DNMT1, DNMT3A), gap junction protein alpha 1 (GJA1), octamer-binding transcription factor 4 [OCT4], insulin-like growth factors 1 and 2 receptors (IGF1R, IGF2R), beta-actin (ACTB)] in pools of days 4-5 morulae by semi-quantitative RT-PCR assay. Percentages of cleaved embryos were similar (p > 0.05) between both culture systems, regardless of the location. OCT4 mRNA abundance was higher (p culture system compared with those from the IZW system when epididymal sperm was used for IVF. No clear correlation between the expression pattern and the culture system could be found for all other genes. It is suggested that OCT4 expression might be affected by the media composition in some conditions and can be the indicator of a better embryo quality. © 2012 Blackwell Verlag GmbH.

  5. Identification of prophages in bacterial genomes by dinucleotide relative abundance difference.

    Directory of Open Access Journals (Sweden)

    K V Srividhya

    Full Text Available BACKGROUND: Prophages are integrated viral forms in bacterial genomes that have been found to contribute to interstrain genetic variability. Many virulence-associated genes are reported to be prophage encoded. Present computational methods to detect prophages are either by identifying possible essential proteins such as integrases or by an extension of this technique, which involves identifying a region containing proteins similar to those occurring in prophages. These methods suffer due to the problem of low sequence similarity at the protein level, which suggests that a nucleotide based approach could be useful. METHODOLOGY: Earlier dinucleotide relative abundance (DRA have been used to identify regions, which deviate from the neighborhood areas, in genomes. We have used the difference in the dinucleotide relative abundance (DRAD between the bacterial and prophage DNA to aid location of DNA stretches that could be of prophage origin in bacterial genomes. Prophage sequences which deviate from bacterial regions in their dinucleotide frequencies are detected by scanning bacterial genome sequences. The method was validated using a subset of genomes with prophage data from literature reports. A web interface for prophage scan based on this method is available at http://bicmku.in:8082/prophagedb/dra.html. Two hundred bacterial genomes which do not have annotated prophages have been scanned for prophage regions using this method. CONCLUSIONS: The relative dinucleotide distribution difference helps detect prophage regions in genome sequences. The usefulness of this method is seen in the identification of 461 highly probable loci pertaining to prophages which have not been annotated so earlier. This work emphasizes the need to extend the efforts to detect and annotate prophage elements in genome sequences.

  6. Measurements of periods, relative abundances and absolute yields of delayed neutrons from fast neutron induced fission of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Piksaikine, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    The experimental method for measurements of the delayed neutron yields and period is presented. The preliminary results of the total yield, relative abundances and periods are shown comparing with the previously reported values. (J.P.N.)

  7. Application of hierarchical oligonucleotide primer extension (HOPE) to assess relative abundances of ammonia- and nitrite-oxidizing bacteria

    KAUST Repository

    Scarascia, Giantommaso; Cheng, Hong; Harb, Moustapha; Hong, Pei-Ying

    2017-01-01

    for ensuring the efficiency of nitrification in water treatment systems. Hierarchical oligonucleotide primer extension (HOPE), previously developed to rapidly quantify relative abundances of specific microbial groups of interest, was applied in this study

  8. Relative Abundance in Bacterial and Fungal Gut Microbes in Obese Children: A Case Control Study.

    Science.gov (United States)

    Borgo, Francesca; Verduci, Elvira; Riva, Alessandra; Lassandro, Carlotta; Riva, Enrica; Morace, Giulia; Borghi, Elisa

    2017-02-01

    Differences in relative proportions of gut microbial communities in adults have been correlated with intestinal diseases and obesity. In this study we evaluated the gut microbiota biodiversity, both bacterial and fungal, in obese and normal-weight school-aged children. We studied 28 obese (mean age 10.03 ± 0.68) and 33 age- and sex-matched normal-weight children. BMI z-scores were calculated, and the obesity condition was defined according to the WHO criteria. Fecal samples were analyzed by 16S rRNA amplification followed by denaturing gradient gel electrophoresis (DGGE) analysis and sequencing. Real-time polymerase chain reaction (PCR) was performed to quantify the most representative microbial species and genera. DGGE profiles showed high bacterial biodiversity without significant correlations with BMI z-score groups. Compared to bacterial profiles, we observed lower richness in yeast species. Sequence of the most representative bands gave back Eubacterium rectale, Saccharomyces cerevisiae, Candida albicans, and C. glabrata as present in all samples. Debaryomyces hansenii was present only in two obese children. Obese children revealed a significantly lower abundance in Akkermansia muciniphyla, Faecalibacterium prausnitzii, Bacteroides/Prevotella group, Candida spp., and Saccharomyces spp. (P = 0.031, P = 0.044, P = 0.003, P = 0.047, and P = 0.034, respectively). Taking into account the complexity of obesity, our data suggest that differences in relative abundance of some core microbial species, preexisting or diet driven, could actively be part of its etiology. This study improved our knowledge about the fungal population in the pediatric school-age population and highlighted the need to consider the influence of cross-kingdom relationships.

  9. Application of hierarchical oligonucleotide primer extension (HOPE) to assess relative abundances of ammonia- and nitrite-oxidizing bacteria

    KAUST Repository

    Scarascia, Giantommaso

    2017-04-04

    Background: Establishing an optimal proportion of nitrifying microbial populations, including ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), complete nitrite oxidizers (comammox) and ammonia-oxidizing archaea (AOA), is important for ensuring the efficiency of nitrification in water treatment systems. Hierarchical oligonucleotide primer extension (HOPE), previously developed to rapidly quantify relative abundances of specific microbial groups of interest, was applied in this study to track the abundances of the important nitrifying bacterial populations. Results: The method was tested against biomass obtained from a laboratory-scale biofilm-based trickling reactor, and the findings were validated against those obtained by 16S rRNA gene-based amplicon sequencing. Our findings indicated a good correlation between the relative abundance of nitrifying bacterial populations obtained using both HOPE and amplicon sequencing. HOPE showed a significant increase in the relative abundance of AOB, specifically Nitrosomonas, with increasing ammonium content and shock loading (p < 0.001). In contrast, Nitrosospira remained stable in its relative abundance against the total community throughout the operational phases. There was a corresponding significant decrease in the relative abundance of NOB, specifically Nitrospira and those affiliated to comammox, during the shock loading. Based on the relative abundance of AOB and NOB (including commamox) obtained from HOPE, it was determined that the optimal ratio of AOB against NOB ranged from 0.2 to 2.5 during stable reactor performance. Conclusions: Overall, the HOPE method was developed and validated against 16S rRNA gene-based amplicon sequencing for the purpose of performing simultaneous monitoring of relative abundance of nitrifying populations. Quantitative measurements of these nitrifying populations obtained via HOPE would be indicative of reactor performance and nitrification functionality.

  10. Heterogeneity of elemental composition and natural abundance of stables isotopes of C and N in soils and leaves of mangroves at their southernmost West Atlantic range.

    Science.gov (United States)

    Tognella, M M P; Soares, M L G; Cuevas, E; Medina, E

    2016-01-01

    Mangrove communities were selected in the state of Santa Catarina, Brazil, near their southernmost limit of distribution, to study mineral nutrient relation in soils and plants. Communities included three true mangrove species, Rhizophora mangle, Laguncularia racemosa and Avicennia germinans, and two associated species, the fern Acrostichum danaeifolium, and the grass Spartina densiflora. The sites included communities in the lower Río Tavares near Florianopolis city, Sonho beach near Palhoça city, and the Santo Antonio lagoon. These sites included a full range of mangroves under humid climate where winter temperatures, instead of salinity, may be the main factor regulating their productive capacity and species composition. Soil salinity was determined by the concentration of soluble Na, and soil C and N were linearly correlated indicating their association in organic matter. Tavares site showed higher specific conductivity, and concentrations of Na and Mg in the soil layer below 40 cm depth, indicating larger influence of marine water. Isotopic signature of C increased with soil depth suggesting that microorganisms decomposing organic matter are releasing 13C depleted CO2. Nitrogen isotopic signature decreased with soil depth, indicating enrichment in 15N possibly as a result of denitrification in the upper soil layers. Mineral elements in leaf tissues showed A. schaueriana with higher concentrations of N, P, Na, K, Cu, Zn, and Na/Ca ratio. Spartina densiflora was characterized by the lowest N and K concentrations, and the highest concentrations of Al and Fe. Rhizophora mangle and L. racemosa had the highest Ca concentrations. Carbon isotopic signatures identified S. densiflora as a C4 plant, and A. schaueriana as the mangrove species occupying comparatively more water stressed microsites than the rest. Leaf nitrogen isotopic signatures were positive, in correspondence with the soil values. The results support the hypothesis that sites sampled were comparatively

  11. Hierarchical spatial models for predicting pygmy rabbit distribution and relative abundance

    Science.gov (United States)

    Wilson, T.L.; Odei, J.B.; Hooten, M.B.; Edwards, T.C.

    2010-01-01

    Conservationists routinely use species distribution models to plan conservation, restoration and development actions, while ecologists use them to infer process from pattern. These models tend to work well for common or easily observable species, but are of limited utility for rare and cryptic species. This may be because honest accounting of known observation bias and spatial autocorrelation are rarely included, thereby limiting statistical inference of resulting distribution maps. We specified and implemented a spatially explicit Bayesian hierarchical model for a cryptic mammal species (pygmy rabbit Brachylagus idahoensis). Our approach used two levels of indirect sign that are naturally hierarchical (burrows and faecal pellets) to build a model that allows for inference on regression coefficients as well as spatially explicit model parameters. We also produced maps of rabbit distribution (occupied burrows) and relative abundance (number of burrows expected to be occupied by pygmy rabbits). The model demonstrated statistically rigorous spatial prediction by including spatial autocorrelation and measurement uncertainty. We demonstrated flexibility of our modelling framework by depicting probabilistic distribution predictions using different assumptions of pygmy rabbit habitat requirements. Spatial representations of the variance of posterior predictive distributions were obtained to evaluate heterogeneity in model fit across the spatial domain. Leave-one-out cross-validation was conducted to evaluate the overall model fit. Synthesis and applications. Our method draws on the strengths of previous work, thereby bridging and extending two active areas of ecological research: species distribution models and multi-state occupancy modelling. Our framework can be extended to encompass both larger extents and other species for which direct estimation of abundance is difficult. ?? 2010 The Authors. Journal compilation ?? 2010 British Ecological Society.

  12. Chemical equilibria relating the isotopic hydrogens at low temperatures

    International Nuclear Information System (INIS)

    Pyper, J.W.; Souers, P.C.

    1976-01-01

    Hydrogen fusion will require a fuel mixture of liquefied or frozen D 2 and T 2 . The composition of this fuel mixture is described by the equilibrium constant K/sub DT/. The theory of isotopic exchange reactions is discussed as applied to the hydrogen isotopes. A literature survey of the values of K/sub HD/, K/sub HT/, and K/sub DT/ found no values of K/sub DT/ for temperatures below 25 0 K and no values of K/sub HD/ and K/sub HT/ for temperatures below 50 0 K. The existing data are critically evaluated, and simplified formulas for the three equilibrium constants in the temperature range 50 to 300 0 K are derived from them. Harmonic approximation theory with rotational correction was used to calculate values of K/sub HD/, K/sub HT/, and K/sub DT/ in the temperature range 4.2 to 50 0 K. It is found that K/sub DT/ = 2.995 exp(-10.82/T) in the temperature range 16.7 to 33.3 0 K to an accuracy of 1%. Tables, graphs, and equations of K/sub HD/, K/sub HT/, and K/sub DT/ are given for the temperature range 4.2 to 50 0 K. 27 references, 14 tables, 8 figures

  13. Coyote abundance in relation to habitat characteristics in Sierra San Luis, Sonora, Mexico

    Science.gov (United States)

    Eduardo Ponce Guevara; Karla Pelz Serrano; Carlos A. Lopez Gonzalez

    2005-01-01

    Coyotes have expanded their historical distribution range because of anthropogenic activities and habitat transformation, where forests have been considered marginal habitat. We tested the relationship between vegetation structure and coyote abundance in different habitat types. We expected to find a higher abundance in open lands than in thicker areas. We used scent...

  14. Alpha-capture reaction rates for 22 Ne (α , n) via sub-Coulomb alpha-transfer and its effect on final abundances of s-process isotopes

    Science.gov (United States)

    Jayatissa, Heshani; Rogachev, Grigory; Koshchiy, Yevgeny; Goldberg, Vladilen; Hooker, Joshua; Hunt, Curtis; Magana, Cordero; Roeder, Brian; Saastamoinen, Antti; Spiridon, Alexandria; Upadhyayula, Sriteja; Trippella, Oscar

    2017-09-01

    The 22 Ne (α , n) reaction is a very important neutron source reaction for the slow neutron capture process (s-process) in asymptotic giant branch stars. These direct measurements are very difficult to carry out at the energy regimes of interest for astrophysics (Gamow energies) due to the extremely small reaction cross section. The large uncertainties introduced when extrapolating direct measurements at high energies down to the Gamow energies can be overcome by measuring the Asymptotic Normalization Coefficients (ANC) of the relevant states using α-transfer reactions at sub-Coulomb energies to reduce the optical model dependence. The study of the 22Ne(6Li,d) and 22Ne(7Li,t) reaction was carried out at the Cyclotron Institute at Texas A&M University. The α-ANC measurements for the near α-threshold resonances of 26Mg provide constraints for the 22Ne(α,n) reaction rate. The effect of this reaction rate on the final abundances of the s-process isotopes will be discussed.

  15. Constraints on the Mass–Richness Relation from the Abundance and Weak Lensing of SDSS Clusters

    Science.gov (United States)

    Murata, Ryoma; Nishimichi, Takahiro; Takada, Masahiro; Miyatake, Hironao; Shirasaki, Masato; More, Surhud; Takahashi, Ryuichi; Osato, Ken

    2018-02-01

    We constrain the scaling relation between optical richness (λ) and halo mass (M) for a sample of Sloan Digital Sky Survey (SDSS) red-sequence Matched-filter Probabilistic Percolation (redMaPPer) galaxy clusters within the context of the Planck cosmological model. We use a forward modeling approach where we model the probability distribution of optical richness for a given mass, P({ln}λ | M). To model the abundance and the stacked lensing profiles, we use an emulator specifically built to interpolate the halo mass function and the stacked lensing profile for an arbitrary set of halo mass and redshift, which is calibrated based on a suite of high-resolution N-body simulations. We apply our method to 8312 SDSS redMaPPer clusters with 20 ≤ λ ≤ 100 and 0.10 ≤ z λ ≤ 0.33 and show that the lognormal distribution model for P(λ | M), with four free parameters, well reproduces the measured abundances and lensing profiles simultaneously. The constraints are characterized by the mean relation, (M)=A+B{ln}(M/{M}pivot}), with A={3.207}-0.046+0.044 and B={0.993}-0.055+0.041 (68% CL), where the pivot mass scale M pivot = 3 × 1014 h ‑1 M ⊙, and the scatter {σ }lnλ | M}={σ }0+q{ln}(M/{M}pivot}) with {σ }0={0.456}-0.039+0.047 and q=-{0.169}-0.026+0.035. We find that a large scatter in halo masses is required at the lowest-richness bins (20 ≤ λ ≲ 30) in order to reproduce the measurements. Without such a large scatter, the model prediction for the lensing profiles tends to overestimate the measured amplitudes. This might imply a possible contamination of intrinsically low-richness clusters due to the projection effects. Such a low-mass halo contribution is significantly reduced when applying our method to the sample of 30 ≤ λ ≤ 100.

  16. 2. Workshop 'Isotopes in Nature'. 1

    International Nuclear Information System (INIS)

    1979-11-01

    The workshop was aimed at discussing in detail the following problems: (1) distribution of stable and radioactive isotopes in nature, (2) theoretical and experimental studies of isotopic effects in natural processes, (3) problems of sample preparation and sample measurement in determining the relative abundance of stable isotopes or radioactive isotopes in nature, (4) age estimations of samples from different areas of the geosphere, (5) contributions to the specification of global and regional substance cycles in nature with the aid of isotopic and geochemical studies. 75 summaries are included

  17. Atomic collisions related to atomic laser isotope separation

    International Nuclear Information System (INIS)

    Shibata, Takemasa

    1995-01-01

    Atomic collisions are important in various places in atomic vapor laser isotope separation (AVLIS). At a vaporization zone, many atomic collisions due to high density have influence on the atomic beam characteristics such as velocity distribution and metastable states' populations at a separation zone. In the separation zone, a symmetric charge transfer between the produced ions and the neutral atoms may degrade selectivity. We have measured atomic excitation temperatures of atomic beams and symmetric charge transfer cross sections for gadolinium and neodymium. Gadolinium and neodymium are both lanthanides. Nevertheless, results for gadolinium and neodymium are very different. The gadolinium atom has one 5d electron and neodymium atom has no 5d electron. It is considered that the differences are due to existence of 5d electron. (author)

  18. Seasonal abundance of soil arthropods in relation to meteorological and edaphic factors in the agroecosystems of Faisalabad, Punjab, Pakistan

    Science.gov (United States)

    Shakir, Muhammad Mussadiq; Ahmed, Sohail

    2015-05-01

    Soil arthropods are an important component of agroecosystems, contributing significantly to their biodiversity and functioning. However, seasonal patterns, population dynamics, and significant roles of these soil arthropods in improvement of soil structures and functions are influenced by many factors. The objective of the current study was to investigate soil arthropod abundance in relation to a blend of meteorological and edaphic factors and to find out the difference in abundance among various crops (sugarcane, cotton, wheat, alfalfa fodder, and citrus orchards). The arthropod sampling was done by pitfall traps and Tullgren extractions on fortnightly intervals. Soil temperature and relative humidity were noted on the field sites while analysis for soil pH, organic matter, and soil moisture contents were done in the laboratory. The rainfall data was obtained from an observatory. Results showed that significant differences were found in soil arthropod abundance across different sampling months and crops. Out of total 13,673 soil arthropods sampled, 38 % belonged to Collembola, followed by 15 % Hymenoptera, 15 % Acarina, 11 % Myriapods, 6 % Coleoptera, 5 % Orthoptera, and 5 % Araneae. Mean abundance per sample was highest in summer months as compared to winter. Overall abundance per sample was significantly different between all crops ( p Aranae, Coleoptera), least abundant (Dermaptera, Hemiptera, Diptera), and rare (Blattaria, Isoptera, Diplura, Lepidoptera). Soil temperature and soil organic matter showed significant positive correlation with abundance, while relative humidity was significantly negatively correlated. Soil moisture and soil pH showed no significant correlations while no correlation was found with total rainfall. PCA analysis revealed that soil surface arthropods were the major contributors of variation in overall abundance in extreme temperature months while microarthropods in low-temperature months. CCA analysis revealed the occurrence of

  19. Intake of Meat Proteins Substantially Increased the Relative Abundance of Genus Lactobacillus in Rat Feces.

    Directory of Open Access Journals (Sweden)

    Yingying Zhu

    Full Text Available Diet has been shown to have a critical influence on gut bacteria and host health, and high levels of red meat in diet have been shown to increase colonic DNA damage and thus be harmful to gut health. However, previous studies focused more on the effects of meat than of meat proteins. In order to investigate whether intake of meat proteins affects the composition and metabolic activities of gut microbiota, feces were collected from growing rats that were fed with either meat proteins (from beef, pork or fish or non-meat proteins (casein or soy for 14 days. The resulting composition of gut microbiota was profiled by sequencing the V4-V5 region of the 16S ribosomal RNA genes and the short chain fatty acids (SCFAs were analyzed using gas chromatography. The composition of gut microbiota and SCFA levels were significantly different between the five diet groups. At a recommended dose of 20% protein in the diet, meat protein-fed rats had a higher relative abundance of the beneficial genus Lactobacillus, but lower levels of SCFAs and SCFA-producing bacteria including Fusobacterium, Bacteroides and Prevotella, compared with the soy protein-fed group. Further work is needed on the regulatory pathways linking dietary protein intake to gut microbiota.

  20. Intake of Meat Proteins Substantially Increased the Relative Abundance of Genus Lactobacillus in Rat Feces.

    Science.gov (United States)

    Zhu, Yingying; Lin, Xisha; Li, He; Li, Yingqiu; Shi, Xuebin; Zhao, Fan; Xu, Xinglian; Li, Chunbao; Zhou, Guanghong

    2016-01-01

    Diet has been shown to have a critical influence on gut bacteria and host health, and high levels of red meat in diet have been shown to increase colonic DNA damage and thus be harmful to gut health. However, previous studies focused more on the effects of meat than of meat proteins. In order to investigate whether intake of meat proteins affects the composition and metabolic activities of gut microbiota, feces were collected from growing rats that were fed with either meat proteins (from beef, pork or fish) or non-meat proteins (casein or soy) for 14 days. The resulting composition of gut microbiota was profiled by sequencing the V4-V5 region of the 16S ribosomal RNA genes and the short chain fatty acids (SCFAs) were analyzed using gas chromatography. The composition of gut microbiota and SCFA levels were significantly different between the five diet groups. At a recommended dose of 20% protein in the diet, meat protein-fed rats had a higher relative abundance of the beneficial genus Lactobacillus, but lower levels of SCFAs and SCFA-producing bacteria including Fusobacterium, Bacteroides and Prevotella, compared with the soy protein-fed group. Further work is needed on the regulatory pathways linking dietary protein intake to gut microbiota.

  1. Intake of Meat Proteins Substantially Increased the Relative Abundance of Genus Lactobacillus in Rat Feces

    Science.gov (United States)

    Zhu, Yingying; Lin, Xisha; Li, He; Li, Yingqiu; Shi, Xuebin; Zhao, Fan; Xu, Xinglian; Li, Chunbao; Zhou, Guanghong

    2016-01-01

    Diet has been shown to have a critical influence on gut bacteria and host health, and high levels of red meat in diet have been shown to increase colonic DNA damage and thus be harmful to gut health. However, previous studies focused more on the effects of meat than of meat proteins. In order to investigate whether intake of meat proteins affects the composition and metabolic activities of gut microbiota, feces were collected from growing rats that were fed with either meat proteins (from beef, pork or fish) or non-meat proteins (casein or soy) for 14 days. The resulting composition of gut microbiota was profiled by sequencing the V4-V5 region of the 16S ribosomal RNA genes and the short chain fatty acids (SCFAs) were analyzed using gas chromatography. The composition of gut microbiota and SCFA levels were significantly different between the five diet groups. At a recommended dose of 20% protein in the diet, meat protein-fed rats had a higher relative abundance of the beneficial genus Lactobacillus, but lower levels of SCFAs and SCFA-producing bacteria including Fusobacterium, Bacteroides and Prevotella, compared with the soy protein-fed group. Further work is needed on the regulatory pathways linking dietary protein intake to gut microbiota. PMID:27042829

  2. Changes in Natural Abundance Carbon Stable isotopes of Human Blood and Saliva After 24 Days of Controlled Carbohydrate Supplementation

    Science.gov (United States)

    Kraft, R. A.; Jahren, A. H.; Baer, D. J.; Caballero, B.

    2008-12-01

    the δ13C value of their blood and saliva relative to baseline: blood clot was enriched by 0.27‰; blood serum by 0.50‰ and saliva by 1.12‰. We believe this overall enrichment resulted from a 13C-enriched bulk diet (δ13C = - 20.42‰) relative to the subjects free-living diet. Evidence for this derives from inspection of foods within the bulk diet provided, compared to published profiles of the typical American diet. We will discuss possible complicating factors, such as differential absorption and metabolism of the supplements according to solubility and caloric value. These results are encouraging for the development of a δ13C blood serum biomarker that, in the company of other tests, could be used to indicate a change in carbohydrate intake. Bray, G.A., Nielsen, S.J. and Popkin, B.M., 2004. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. American Journal of Clinical Nutrition, 79: 537-543. Havel, P.J., 2005. Dietary fructose: Implications for dysregulation of energy homeostasis and lipid/carbohydrate metabolism. Nutrition Reviews, 63(5): 133-157. Tilman D., 1998. The greening of the green revolution. Nature, 396:211-212.

  3. Yield in almond is related more to the abundance of flowers than the relative number of flowers that set fruit

    Directory of Open Access Journals (Sweden)

    Sergio Tombesi

    2016-11-01

    Full Text Available Almond tree yield is a function of the number of flowers on a tree and the percentage of flowers that set fruit. Almonds are borne on spurs (short proleptic shoots that can have both leaves and flowers. Almond tree spur dynamics research has documented that previous year spur leaf area is a predictive parameter for year-to-year spur survival, spur flowering and to a lesser extent spur fruiting, while previous year fruit bearing has a negative impact on subsequent year flowering. However, a question remained about whether yields are more dependent on flower numbers or relative fruit set of the flowers that are present. The aim of the present work was to compare the importance of flower abundance with that of relative fruit set in determining the productivity of a population of tagged spurs in almond trees over a 6-year period. Overall tree yield among years was more sensitive to total number of flowers on a tree rather than relative fruit set. These results emphasize the importance of maintaining large populations of healthy flowering spurs for sustained high production in almond orchards.

  4. Relation of desert pupfish abundance to selected environmental variables in natural and manmade habitats in the Salton Sea basin

    Science.gov (United States)

    Martin, B.A.; Saiki, M.K.

    2005-01-01

    We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected biological and physicochemical variables in natural and manmade habitats within the Salton Sea Basin. Field sampling in a natural tributary, Salt Creek, and three agricultural drains captured eight species including pupfish (1.1% of the total catch), the only native species encountered. According to Bray-Curtis resemblance functions, fish species assemblages differed mostly between Salt Creek and the drains (i.e., the three drains had relatively similar species assemblages). Pupfish numbers and environmental variables varied among sites and sample periods. Canonical correlation showed that pupfish abundance was positively correlated with abundance of western mosquitofish, Gambusia affinis, and negatively correlated with abundance of porthole livebearers, Poeciliopsis gracilis, tilapias (Sarotherodon mossambica and Tilapia zillii), longjaw mudsuckers, Gillichthys mirabilis, and mollies (Poecilia latipinnaandPoecilia mexicana). In addition, pupfish abundance was positively correlated with cover, pH, and salinity, and negatively correlated with sediment factor (a measure of sediment grain size) and dissolved oxygen. Pupfish abundance was generally highest in habitats where water quality extremes (especially high pH and salinity, and low dissolved oxygen) seemingly limited the occurrence of nonnative fishes. This study also documented evidence of predation by mudsuckers on pupfish. These findings support the contention of many resource managers that pupfish populations are adversely influenced by ecological interactions with nonnative fishes. ?? Springer 2005.

  5. Relating species abundance distributions to species-area curves in two Mediterranean-type shrublands

    Science.gov (United States)

    Keeley, Jon E.

    2003-01-01

    Based on both theoretical and empirical studies there is evidence that different species abundance distributions underlie different species-area relationships. Here I show that Australian and Californian shrubland communities (at the scale from 1 to 1000 m2) exhibit different species-area relationships and different species abundance patterns. The species-area relationship in Australian heathlands best fits an exponential model and species abundance (based on both density and cover) follows a narrow log normal distribution. In contrast, the species-area relationship in Californian shrublands is best fit with the power model and, although species abundance appears to fit a log normal distribution, the distribution is much broader than in Australian heathlands. I hypothesize that the primary driver of these differences is the abundance of small-stature annual species in California and the lack of annuals in Australian heathlands. Species-area is best fit by an exponential model in Australian heathlands because the bulk of the species are common and thus the species-area curves initially rise rapidly between 1 and 100 m2. Annuals in Californian shrublands generate very broad species abundance distributions with many uncommon or rare species. The power function is a better model in these communities because richness increases slowly from 1 to 100 m2 but more rapidly between 100 and 1000 m2due to the abundance of rare or uncommon species that are more likely to be encountered at coarser spatial scales. The implications of this study are that both the exponential and power function models are legitimate representations of species-area relationships in different plant communities. Also, structural differences in community organization, arising from different species abundance distributions, may lead to different species-area curves, and this may be tied to patterns of life form distribution.

  6. Phytoplankton abundance in relation to the quality of the coastal water – Arabian Gulf, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Mostafa Abdel Mohsen El Gammal

    2017-12-01

    Full Text Available Phytoplankton abundance in relation to some physicochemical characters of the costal water of Arabian Gulf (Saudi Arabia was studied for one year. The sampling program included 15 locations in Dammam, Saihat, Al-Qatif, Al-Awamia and Safwa. Water samples were analyzed monthly for these parameters; temperature, pH, salinity, dissolved oxygen, nitrite, nitrate, ammonia, carbon dioxide, total chloride, reactive orthophosphate and total phosphorus and alkalinity, also phytoplankton communities were identified and Chlorophyll a was estimated. The results showed that, the high phytoplankton density attaining the maximum (190.3 × 104/m3 during May and June, and the minimum (10.4 × 104/m3 during November and December. Forty Five species belonging to 5 phytoplankton groups were recorded. Bacillariophyceae was the first dominant group forming 48% of the total phytoplankton communities (23 species. The dominant species of Bacillariophyceae were Pleurosigma strigosum, Pleurosigma elongatum, Lyrella clavata, Rhizosolenia shrubsolei, Cylindrotheca closterium, Nitzschia panduriform, Nitzschia longissimia, Amphora sp and Stephanopyxis. Dinophyceae was the second dominant group and formed 31% of the total phytoplankton communities (10 species; the dominant species were Ceratium fusus, Heterosigma sp, Ceratium furca, Prorocentrum triestium, Protoperidinium sp, Gyrodinium spirale, Noctiluca scintillans and Scrippsiella trochoidea. Cyanophyceae formed 13% (5 species where Nostoc sp, Oscillatoria and Merismopedia sp were the dominant species. Chlorophyceae had 8% (6 species; Scendesmus sp., Chlorella sp., Chlamydomonas sp., Dunaliella salina and Nannochloropsis sp were the dominant species. The Euglinophyceae was rare only one species (Euglina sp. The relationship was positive between the phytoplankton, chlorophyll a and carbon dioxide while negative amongst dissolved oxygen and total nitrogen. This research indicated that the relation between water quality

  7. Heterogeneity of elemental composition and natural abundance of stables isotopes of C and N in soils and leaves of mangroves at their southernmost West Atlantic range

    Directory of Open Access Journals (Sweden)

    M. M. P. Tognella

    Full Text Available Abstract Mangrove communities were selected in the state of Santa Catarina, Brazil, near their southernmost limit of distribution, to study mineral nutrient relation in soils and plants. Communities included three true mangrove species, Rhizophora mangle, Laguncularia racemosa and Avicennia germinans, and two associated species, the fern Acrostichum danaeifolium, and the grass Spartina densiflora. The sites included communities in the lower Río Tavares near Florianopolis city, Sonho beach near Palhoça city, and the Santo Antonio lagoon. These sites included a full range of mangroves under humid climate where winter temperatures, instead of salinity, may be the main factor regulating their productive capacity and species composition. Soil salinity was determined by the concentration of soluble Na, and soil C and N were linearly correlated indicating their association in organic matter. Tavares site showed higher specific conductivity, and concentrations of Na and Mg in the soil layer below 40 cm depth, indicating larger influence of marine water. Isotopic signature of C increased with soil depth suggesting that microorganisms decomposing organic matter are releasing 13C depleted CO2. Nitrogen isotopic signature decreased with soil depth, indicating enrichment in 15N possibly as a result of denitrification in the upper soil layers. Mineral elements in leaf tissues showed A. schaueriana with higher concentrations of N, P, Na, K, Cu, Zn, and Na/Ca ratio. Spartina densiflora was characterized by the lowest N and K concentrations, and the highest concentrations of Al and Fe. Rhizophora mangle and L. racemosa had the highest Ca concentrations. Carbon isotopic signatures identified S. densiflora as a C4 plant, and A. schaueriana as the mangrove species occupying comparatively more water stressed microsites than the rest. Leaf nitrogen isotopic signatures were positive, in correspondence with the soil values. The results support the hypothesis that

  8. Financial development and oil resource abundance-growth relations: evidence from panel data.

    Science.gov (United States)

    Law, Siong Hook; Moradbeigi, Maryam

    2017-10-01

    This study investigates whether financial development dampens the negative impact of oil resource abundance on economic growth. Because of substantial cross-sectional dependence in our data, which contain a core sample of 63 oil-producing countries from 1980 through 2010, we use the common correlated effect mean group (CCEMG) estimator to account for the high degree of heterogeneity and drop the outlier countries. The empirical results reveal that oil resource abundance affects the growth rate in output contingent on the degree of development in financial markets. More developed financial markets can channel the revenues from oil into more productive activities and thus offset the negative effects of oil resource abundance on economic growth. Thus, better financial development can reverse resource curse or enhance resource blessing in oil-rich economies.

  9. Investigation of plutonium abundance and age analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huailong, Wu; Jian, Gong; Fanhua, Hao [China Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry

    2007-06-15

    Based on spectra analysis software, all of the plutonium material peak counts are analyzed. Relatively efficiency calibration is done by the non-coupling peaks of {sup 239}Pu. By using the known isotopes half life and yield, the coupling peaks counts are allocated by non-coupling peaks, consequently the atom ratios of each isotope are gotten. The formula between atom ratio and abundance or age is deduced by plutonium material isotopes decay characteristic. And so the abundance and age of plutonium material is gotten. After some re- peat measurements for a plutonium equipment are completed, a comparison between our analysis results and PC-FRAM and the owner's reference results are done. (authors)

  10. Relative mobility of 1-H atoms of carbohydrates in heterogeneous isotope exchange reactions

    International Nuclear Information System (INIS)

    Akulov, G.P.; Snetkova, E.V.; Kayumov, V.G.; Kaminskii, Yu.L.

    1988-01-01

    The method of competitive reactions was used to determine the relative mobilities of the 1-H atoms of carbohydrates in reactions of heterogeneous isotope exchange, using various reference standards, catalysts, and buffer systems. On the basis of the results obtained, the investigated carbohydrates are ranged in a series of decreasing mobility of the hydrogen atoms exchanged in heterogeneous isotope exchange reactions. It was demonstrated that the mobility of the 1-H atoms is related to the concentration of the acyclic forms of the carbohydrates

  11. External Quality Assurance: Annual Proficiency Test on {sup 15}N and {sup 13}C isotopic abundance in plant materials [Activities of the Soil and Water Management and Crop Nutrition Laboratory, Seibersdorf

    Energy Technology Data Exchange (ETDEWEB)

    Aigner, Martina [Soil and Water Management and Crop Nutrition Laboratory, Joint FAO/IAEA Division for Nuclear Techniques in Food and Agriculture, Seibersdorf (Austria)

    2014-07-15

    Eight out of twelve laboratories (67%) participating in the nitrogen analysis reported {sup 15}N-data within the control limits for the enriched plant sample and eight out of nine (89%) participating laboratories for carbon analysis reported {sup 13}C isotopic abundance results within the control limits for this test sample. The reported analytical data and WEPAL evaluation of the {sup 15}N enriched plant material produced by SWMCNL is shown. All participants received a certificate of participation. Worldwide comparison of stable {sup 15}N and {sup 13}C isotope measurements will provide confidence in the laboratory's analytical performance and is hence an invaluable tool for external quality control. It is hoped that in the future more stable isotope laboratories will make use of this unique opportunity to assess their analytical performance and provide evidence of the high quality of their analytical data.

  12. External Quality Assurance: Annual Proficiency Test on 15N and 13C isotopic abundance in plant materials [Activities of the Soil and Water Management and Crop Nutrition Laboratory, Seibersdorf

    International Nuclear Information System (INIS)

    Aigner, Martina

    2014-01-01

    Eight out of twelve laboratories (67%) participating in the nitrogen analysis reported 15 N-data within the control limits for the enriched plant sample and eight out of nine (89%) participating laboratories for carbon analysis reported 13 C isotopic abundance results within the control limits for this test sample. The reported analytical data and WEPAL evaluation of the 15 N enriched plant material produced by SWMCNL is shown. All participants received a certificate of participation. Worldwide comparison of stable 15 N and 13 C isotope measurements will provide confidence in the laboratory's analytical performance and is hence an invaluable tool for external quality control. It is hoped that in the future more stable isotope laboratories will make use of this unique opportunity to assess their analytical performance and provide evidence of the high quality of their analytical data

  13. Microbial abundance on the eggs of a passerine bird and related fitness consequences between urban and rural habitats.

    Science.gov (United States)

    Lee, Sang-Im; Lee, Hyunna; Jablonski, Piotr G; Choe, Jae Chun; Husby, Magne

    2017-01-01

    Urban environments present novel and challenging habitats to wildlife. In addition to well-known difference in abiotic factors between rural and urban environments, the biotic environment, including microbial fauna, may also differ significantly. In this study, we aimed to compare the change in microbial abundance on eggshells during incubation between urban and rural populations of a passerine bird, the Eurasian Magpie (Pica pica), and examine the consequences of any differences in microbial abundances in terms of hatching success and nestling survival. Using real-time PCR, we quantified the abundances of total bacteria, Escherichia coli/Shigella spp., surfactin-producing Bacillus spp. and Candida albicans on the eggshells of magpies. We found that urban magpie eggs harboured greater abundances of E. coli/Shigella spp. and C. albicans before incubation than rural magpie eggs. During incubation, there was an increase in the total bacterial load, but a decrease in C. albicans on urban eggs relative to rural eggs. Rural eggs showed a greater increase in E. coli/Shigella spp. relative to their urban counterpart. Hatching success of the brood was generally lower in urban than rural population. Nestling survival was differentially related with the eggshell microbial abundance between urban and rural populations, which was speculated to be the result of the difference in the strength of the interaction among the microbes. This is the first demonstration that avian clutches in urban and rural populations differ in eggshell microbial abundance, which can be further related to the difference in hatching success and nestling survival in these two types of environments. We suggest that future studies on the eggshell microbes should investigate the interaction among the microbes, because the incubation and/or environmental factors such as urbanization or climate condition can influence the dynamic interactions among the microbes on the eggshells which can further determine the

  14. The relative abundance of dimethylsulfoniopropionate (DMSP) among other zwitterions in branching coral at Heron Island, southern Great Barrier Reef.

    Science.gov (United States)

    Swan, Hilton B; Deschaseaux, Elisabeth S M; Jones, Graham B; Eyre, Bradley D

    2017-07-01

    Dimethylsulfoniopropionate (DMSP) and eleven other target zwitterions were quantified in the branch tips of six Acropora species and Stylophora pistillata hard coral growing on the reef flat surrounding Heron Island in the southern Great Barrier Reef (GBR), Australia. Hydrophilic interaction liquid chromatography mass spectrometry (HILIC-MS) was used for sample analysis with isotope dilution MS applied to quantify DMSP. The concentration of DMSP was ten times greater in A. aspera than A. valida, with this difference being maintained throughout the spring, summer and winter seasons. In contrast, glycine betaine was present in significantly higher concentrations in these species during the summer than the winter. Exposure of branch tips of A. aspera to air and hypo-saline seawater for up to 1 h did not alter the concentrations of DMSP present in the coral when compared with control samples. DMSP was the most abundant target zwitterion in the six Acropora species examined, ranging from 44-78% of all target zwitterions in A. millepora and A. aspera, respectively. In contrast, DMSP only accounted for 7% in S. pistillata, with glycine betaine and stachydrine collectively accounting for 88% of all target zwitterions in this species. The abundance of DMSP in the six Acropora species examined points to Acropora coral being an important source for the biogeochemical cycling of sulfur throughout the GBR, since this reef-building branching coral dominates the coral cover of the GBR. Graphical Abstract HILIC-MS extracted ion chromatogram showing zwitterionic metabolites from the branching coral Acropora isopora.

  15. The relative influence of prey abundance and co-breeders on the ...

    African Journals Online (AJOL)

    This study investigates if the reproductive performance of polyandrous Pale Chanting-goshawks, Melierax canorus, is governed by the abundance of dominant rodent-prey species or a co-breeding male participating fully in prey being delivered to the female and young. Polyandrous trios in prey-rich habitat, the only habitat ...

  16. Woodland pond salamander abundance in relation to forest management and environmental conditions in northern Wisconsin

    Science.gov (United States)

    Deahn M. Donner; Christine A. Ribic; Albert J. Beck; Dale Higgins; Dan Eklund; Susan. Reinecke

    2015-01-01

    Woodland ponds are important landscape features that help sustain populations of amphibians that require this aquatic habitat for successful reproduction. Species abundance patterns often reflect site-specific differences in hydrology, physical characteristics, and surrounding vegetation. Large-scale processes such as changing land cover and environmental conditions...

  17. A nondestructive technique to monitor the relative abundance of terrestrial salamanders

    Science.gov (United States)

    Richard M. DeGraaf; Mariko. Yamasaki

    1992-01-01

    Salamanders are abundant vertebrates in many forest ecosystems, and their annual biomass production can be important in forest food webs (Pough et al. 1987). Population densities of eastern redback salamanders (Plethodon cinereus) can exceed 2 individuals/m2 in deciduous forests of the United States (Heatwole 1962, Jaeger 1980...

  18. Killer whale presence in relation to naval sonar activity and prey abundance in northern Norway

    NARCIS (Netherlands)

    Kuningas, S.; Kvadsheim, P.H.; Lam, F.P.A.; Miller, P.J.O.

    2013-01-01

    In this study, retrospective data on naval sonar activity and prey abundance were correlated with killer whale sightings within a fjord basin in northern Norway. In addition, passive acoustic and visual marine mammal surveys were conducted before, during, and after a specific navy exercise in 2006.

  19. Relative abundance of resident versus oceanic zooplankton over an interisland reef

    International Nuclear Information System (INIS)

    Alldredge, A.L.; King, J.M.

    1979-01-01

    Zooplankton were collected from various substrate types. Densities were determined and results indicated that demersal plankton were abundant on the Japtan reef flat. Behavioral mechanisms were exhibited by many organisms including swimming near the substrate or in the lees of coral heads. Demersal plankton may provide an important food source for nocturnally foraging fishes

  20. Seasonal variation in copepod abundance in relation to other zooplanktonic groups in the northwestern Mediterranean

    NARCIS (Netherlands)

    Kouwenberg, Juliana H.M.

    1993-01-01

    Abundance of adult copepods and late copepodid stages from the upper 50 m in the Golfe du Lion (N.W. Mediterranean) was studied by the author in 1986, 1987, and 1988 for each season. Altogether 87 stations at 22 fixed locations were sampled in the frame of the multidisciplinary French/Spanish

  1. Natural isotopes abundance of sup 1 sup 5 N and sup 1 sup 3 C in leaves of some N sub 2 -fixing and non N sub 2 -fixing trees and shrubs in Syria

    International Nuclear Information System (INIS)

    Kurdali, F.; Al-Shamma'a, M.

    2009-01-01

    Varability in the natural abundance isotopes of sup 1 sup 5 N and sup 1 sup 3 C in leaves of several legume and non-legume plant species grown at different sites of two areas in semi-arid regions of Syria was determined. In the first area (non-saline soil), the sup 1 sup 5 N values of a number of fixing and non-fixing reference plants ranged from -2.09 to +9.46, depending on plant species and studied site. sup 1 sup 5 N in a number of legume species including Acacia cyanopylla (-1.73), Acacia farnesiana (-0.55), Prosopis juliflora (-1.64) and Medicago arborea (+1.6) were close to the atmospheric value pointing to a major contribution of N sub 2 fixing in these species; whereas, those of reference plants were highly positive (between +3.6 and +9.46%). In the actinorhizal tree, Elaeagnus angustifolia, the sup 1 sup 5 N abundance was far lower (-0.46 to -2.1%) strongly suggesting that the plant obtained large proportional contribution from BNF. In contrast, delta sup 1 sup 5 N values in some other legumes and actinorhizal plants were relatively similar to those of reference plants, suggesting that the contribution of fixed N sub 2 is negligible. On the other hand, delta sup 1 sup 3 C% values in leaves of C3 plants were affected by plant species, ranging from a minimum of -28.67% to a maximum of -23%. However, they were the same within each plant species although they were grown at different sites. Moreover, dual stable isotope analysis in leaves of Prosopis juliflora and other non- legumes grown on a salt affected soil (second area) was also conducted. Results showed that salinity did not affect C assimilation in this woody legume since a higher carbon discrimination was obtained indicating that this plant is a salt tolerant species; whereas, N2-fixation was drastically affected (delta sup 1 sup 5 N= +7.03). (Author)

  2. Variation in local abundance and species richness of stream fishes in relation to dispersal barriers: Implications for management and conservation

    Science.gov (United States)

    Nislow, K.H.; Hudy, M.; Letcher, B.H.; Smith, E.P.

    2011-01-01

    1.Barriers to immigration, all else being equal, should in principle depress local abundance and reduce local species richness. These issues are particularly relevant to stream-dwelling species when improperly designed road crossings act as barriers to migration with potential impacts on the viability of upstream populations. However, because abundance and richness are highly spatially and temporally heterogeneous and the relative importance of immigration on demography is uncertain, population- and community-level effects can be difficult to detect. 2.In this study, we tested the effects of potential barriers to upstream movements on the local abundance and species richness of a diverse assemblage of resident stream fishes in the Monongahela National Forest, West Virginia, U.S.A. Fishes were sampled using simple standard techniques above- and below road crossings that were either likely or unlikely to be barriers to upstream fish movements (based on physical dimensions of the crossing). We predicted that abundance of resident fishes would be lower in the upstream sections of streams with predicted impassable barriers, that the strength of the effect would vary among species and that variable effects on abundance would translate into lower species richness. 3.Supporting these predictions, the statistical model that best accounted for variation in abundance and species richness included a significant interaction between location (upstream or downstream of crossing) and type (passable or impassable crossing). Stream sections located above predicated impassable culverts had fewer than half the number of species and less than half the total fish abundance, while stream sections above and below passable culverts had essentially equivalent richness and abundance. 4.Our results are consistent with the importance of immigration and population connectivity to local abundance and species richness of stream fishes. In turn, these results suggest that when measured at

  3. Diversity, abundance, and host relationships of avian malaria and related haemosporidians in New Mexico pine forests

    Directory of Open Access Journals (Sweden)

    Rosario A. Marroquin-Flores

    2017-08-01

    Full Text Available Avian malaria and related haemosporidian parasites (genera Haemoproteus, Plasmodium, and Leucocytozoon affect bird demography, species range limits, and community structure, yet they remain unsurveyed in most bird communities and populations. We conducted a community-level survey of these vector-transmitted parasites in New Mexico, USA, to describe their diversity, abundance, and host associations. We focused on the breeding-bird community in the transition zone between piñon-juniper woodland and ponderosa pine forests (elevational range: 2,150–2,460 m. We screened 186 birds representing 49 species using both standard PCR and microscopy techniques to detect infections of all three avian haemosporidian genera. We detected infections in 68 out of 186 birds (36.6%, the highest proportion of which were infected with Haemoproteus (20.9%, followed by Leucocytozoon (13.4%, then Plasmodium (8.0%. We sequenced mtDNA for 77 infections representing 43 haplotypes (25 Haemoproteus, 12 Leucocytozoon, 6 Plasmodium. When compared to all previously known haplotypes in the MalAvi and GenBank databases, 63% (27 of the haplotypes we recovered were novel. We found evidence for host specificity at the avian clade and species level, but this specificity was variable among parasite genera, in that Haemoproteus and Leucocytozoon were each restricted to three avian groups (out of six, while Plasmodium occurred in all groups except non-passerines. We found striking variation in infection rate among host species, with nearly universal infection among vireos and no infection among nuthatches. Using rarefaction and extrapolation, we estimated the total avian haemosporidian diversity to be 70 haplotypes (95% CI [43–98]; thus, we may have already sampled ∼60% of the diversity of avian haemosporidians in New Mexico pine forests. It is possible that future studies will find higher diversity in microhabitats or host species that are under-sampled or unsampled in the

  4. Longitudinal patterns in flathead catfish relative abundance and length at age within a large river: Effects of an urban gradient

    Science.gov (United States)

    Paukert, C.P.; Makinster, A.S.

    2009-01-01

    We investigated the spatial variation of flathead catfish (Pylodictis olivaris) relative abundance and growth in the 274 km long Kansas River to determine if population dynamics of catfish are related to urbanization. Electrofishing was conducted at 462 random sites throughout the river in summer, 2005-2006 to collect fish. Relative abundance of age 1 fish (???200mm), subadult (>200-400mm) and adult fish (>400 mm) ranged from 0.34 to 14.67 fish h-1, mean length at age 1 was 165 (range: 128-195) mm total length (TL) and mean length at age 3 was 376 mm TL (range: 293-419mm TL). The proportion of land use within 200 m of the river edge was between 0 and 0.54 urban. River reaches with high relative abundance of age 1 flathead catfish had high relative abundance of subadult and adult catfish. River reaches with fast flathead catfish growth to age 1 had fast growth to age 3. High urban land use and riprap in the riparian area were evident in river reaches near the heavily populated Kansas City and Topeka, Kansas, USA. Reaches with increased number of log jams and islands had decreased riparian agriculture. Areas of low urbanization had faster flathead catfish growth (r = 0.67, p = 0.005). Relative abundance of flathead catfish was higher in more agricultural areas (r = -0.57, p = 0.02). Changes in land use in riverine environments may alter population dynamics of a fish species within a river. Spatial differences in population dynamics need to be considered when evaluating riverine fish populations. Published in 2008 by John Wiley & Sons Ltd.

  5. Water relations link carbon and oxygen isotope discrimination to phloem sap sugar concentration in eucalyptus globulus

    International Nuclear Information System (INIS)

    Cernusak, L.A.; Farquhar, G.D.; Arthur, D.J; Pate, J.S.

    2002-01-01

    Full text: The carbon isotope ratio of phloem sap sugars has been previously observed to correlate strongly with the phloem sap sugar concentration in Eucalyptus globulus. We hypothesized that the correspondence between these two parameters results from co-linearity in their responses to variation in plant water potential. Carbon isotope discrimination is expected to decrease with decreasing plant water potential due to the influence of stomatal conductance on the ratio of intercellular to ambient CO 2 , concentrations (c 1 /c a ). Conversely, we expected the phloem sap sugar concentration to increase with decreasing plant water potential, thereby maintaining positive turgor pressure within the sieve tubes. The study comprised 40 individual Eucalyptus globulus trees growing in three plantations situated on opposing ends of a rainfall gradient in southwestern Australia. A strong correlation was observed between the carbon isotope ratio in phloem sap sugars and phloem sap sugar concentration. Carbon isotope discrimination correlated positively with shoot water potential, whereas phloem sap sugar concentration correlated negatively with shoot water potential. The relationship between carbon isotope discrimination measured in phloem sap sugars collected from the stem and c 1 /c a measured instantaneously on subtending leaves was close to that theoretically predicted. Accordingly, a strong, negative relationship was observed between instantaneous c 1 /c a and the phloem sap sugar concentration. Oxygen isotope discrimination in phloem sap sugars also correlated strongly with phloem sap sugar concentration. A theoretical model suggested that the observed variation in stomatal conductance was sufficient to account for the variation observed in oxygen isotope discrimination across the study. Results strongly support the contention that water relations form a mechanistic link between phloem sap sugar concentration and both instantaneous and integrated measures of the

  6. Iron Abundance in the Prototype PG 1159 Star, GW Vir Pulsator PG 1159-035, and Related Objects

    Science.gov (United States)

    Werner, K.; Rauch, T.; Kruk, J. W.; Kurucz, R. L.

    2011-01-01

    We performed an iron abundance determination of the hot, hydrogen deficient post-AGB star PG 1159-035. which is the prototype of the PG 1159 spectral class and the GW Vir pulsators, and of two related objects (PG 1520+525, PG 1144+005), based on the first detection of Fe VIII lines in stellar photospheres. In another PG 1159 star. PG 1424+535. we detect Fe VII lines. In all four stars, each within T(sub eff) = 110,000-150,000 K, we find a solar iron abundance. This result agrees with our recent abundance analysis of the hottest PG 1159 stars (T(sub eff) = 150,000-200,000 K) that exhibit Fe x lines. On the whole, we find that the PG 1159 stars are not significantly iron deficient, in contrast to previous notions.

  7. Rapid Upregulation of Orai1 Abundance in the Plasma Membrane of Platelets Following Activation with Thrombin and Collagen Related Peptide

    Directory of Open Access Journals (Sweden)

    Guilai Liu

    2015-11-01

    Full Text Available Background: Blood platelets accomplish primary hemostasis following vascular injury and contribute to the orchestration of occlusive vascular disease. Platelets are activated by an increase of cytosolic Ca2+-activity ([Ca2+]i, which is accomplished by Ca2+-release from intracellular stores and subsequent store operated Ca2+ entry (SOCE through Ca2+ release activated Ca2+ channel moiety Orai1. Powerful activators of platelets include thrombin and collagen related peptide (CRP, which are in part effective by activation of small G- protein Rac1. The present study explored the influence of thrombin and CRP on Orai1 protein abundance and cytosolic Ca2+-activity ([Ca2+]i in platelets drawn from wild type mice. Methods: Orai1 protein surface abundance was quantified utilizing CF™488A conjugated antibodies, and [Ca2+]i was determined with Fluo3-fluorescence. Results: In resting platelets, Orai1 protein abundance and [Ca2+]i were low. Thrombin (0.02 U/ml and CRP (5ug/ml within 2 min increased [Ca2+]i and Orai1 protein abundance at the platelet surface. [Ca2+]i was further increased by Ca2+ ionophore ionomycin (1 µM and by store depletion with the sarcoendoplasmatic Ca2+ ATPase inhibitor thapsigargin (1 µM. However, Orai1 protein abundance at the platelet surface was not significantly affected by ionomycin and only slightly increased by thapsigargin. The effect of thrombin and CRP on Orai1 abundance and [Ca2+]i was significantly blunted by Rac1 inhibitor NSC23766 (50 µM. Conclusion: The increase of [Ca2+]i following stimulation of platelets with thrombin and collagen related peptide is potentiated by ultrarapid Rac1 sensitive translocation of Orai1 into the cell membrane.

  8. Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

    Directory of Open Access Journals (Sweden)

    F. Siddika

    2012-06-01

    Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

  9. Nicotine, acetanilide and urea multi-level2H-,13C- and15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry

    Science.gov (United States)

    Schimmelmann, A.; Albertino, A.; Sauer, P.E.; Qi, H.; Molinie, R.; Mesnard, F.

    2009-01-01

    Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the S values of these reference materials should bracket the isotopic range of samples with unknown S values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for ??13C and ??13N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: ??2Hnicotine -162 to -45%o, ??13Cnicotine -30.05 to +7.72%, ?? 15Nnicotine -6.03 to +33.62%; ??15N acetanilide +1-18 to +40.57%; ??13Curea -34.13 to +11.71%, ??15Nurea +0.26 to +40.61% (recommended ?? values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as the first organic nitrogen stable isotope reference materials for GC-IRMS that are available with different ??13N

  10. Nicotine, acetanilide and urea multi-level 2H-, 13C- and 15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry.

    Science.gov (United States)

    Schimmelmann, Arndt; Albertino, Andrea; Sauer, Peter E; Qi, Haiping; Molinie, Roland; Mesnard, François

    2009-11-01

    Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the delta values of these reference materials should bracket the isotopic range of samples with unknown delta values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for delta13C and delta15N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: delta2H(nicotine) -162 to -45 per thousand, delta13C(nicotine) -30.05 to +7.72 per thousand, delta15N(nicotine) -6.03 to +33.62 per thousand; delta15N(acetanilide) +1.18 to +40.57 per thousand; delta13C(urea) -34.13 to +11.71 per thousand, delta15N(urea) +0.26 to +40.61 per thousand (recommended delta values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as

  11. Temporal Patterns in the Abundance of a Critically Endangered Marsupial Relates to Disturbance by Roads and Agriculture.

    Science.gov (United States)

    Yeatman, Georgina J; Wayne, Adrian F; Mills, Harriet R; Prince, Jane

    2016-01-01

    The aim of this study was to investigate how landscape disturbance associated with roads, agriculture and forestry influenced temporal patterns in woylie (Bettongia penicillata) abundance before, during and after periods of rapid population change. Data were collected from an area of approximately 140,000 ha of forest within the Upper Warren region in south-western Australia. Woylie abundance was measured using cage trapping at 22 grid and five transect locations with varying degrees of landscape disturbance between 1994 and 2012. We found evidence that the distribution and abundance of woylies over time appears to be related to the degree of fragmentation by roads and proximity to agriculture. Sites furthest from agriculture supported a greater abundance of woylies and had slower rates of population decline. Sites with fewer roads had a greater abundance of woylies generally and a greater rate of increase in abundance after the implementation of invasive predator control. The results of this study suggest that landscape disturbance is less important at peak population densities, but during times of environmental and population change, sites less dissected by roads and agriculture better support woylie populations. This may be due to the role these factors play in increasing the vulnerability of woylies to introduced predators, population fragmentation, weed species invasion, mortality from road collisions or a reduction in available habitat. Strategies that reduce the impact of disturbance on woylie populations could include the rationalisation of forest tracks and consolidation of contiguous habitat through the acquisition of private property. Reducing the impact of disturbance in the Upper Warren region could improve the resilience of this critically important woylie population during future environmental change.

  12. Studies on osteoporosis in Chile using isotope-related techniques

    International Nuclear Information System (INIS)

    Lobo, G.

    1998-01-01

    The relationship found between BMD of the lumbar spine with the anthropomorphic parameters (age, sex, body size and bone area) in the normal Chilean population studied, was different from the relationship found between BMD of both hips with the same parameters. To determine peak bone mass it is necessary to increase the number of individuals studied. This is specially true for BMD of the lumbar spine. It seems important for the correct interpretation of BMD studies to determine local values for normals, specially for the analysis of BMD in the lumbar spine, which is related to body and bone size. It is necessary to normalize the data base for anthropomorphic parameters specially in epidemiological studies. Knowledge of these parameters for the normal data base used in the different densitometers is highly desirable. There are some differences between this data base and that provided by Hologic, specially for spine in both sexes. This difference could be explained by size related factors. There is a correlation between osteocalcin levels and BMD in lumbar spine and both femoral necks only in women

  13. Diet and condition of mesopredators on coral reefs in relation to shark abundance.

    Science.gov (United States)

    Barley, Shanta C; Meekan, Mark G; Meeuwig, Jessica J

    2017-01-01

    Reef sharks may influence the foraging behaviour of mesopredatory teleosts on coral reefs via both risk effects and competitive exclusion. We used a "natural experiment" to test the hypothesis that the loss of sharks on coral reefs can influence the diet and body condition of mesopredatory fishes by comparing two remote, atoll-like reef systems, the Rowley Shoals and the Scott Reefs, in northwestern Australia. The Rowley Shoals are a marine reserve where sharks are abundant, whereas at the Scott Reefs numbers of sharks have been reduced by centuries of targeted fishing. On reefs where sharks were rare, the gut contents of five species of mesopredatory teleosts largely contained fish while on reefs with abundant sharks, the same mesopredatory species consumed a larger proportion of benthic invertebrates. These measures of diet were correlated with changes in body condition, such that the condition of mesopredatory teleosts was significantly poorer on reefs with higher shark abundance. Condition was defined as body weight, height and width for a given length and also estimated via several indices of condition. Due to the nature of natural experiments, alternative explanations cannot be discounted. However, the results were consistent with the hypothesis that loss of sharks may influence the diet and condition of mesopredators and by association, their fecundity and trophic role. Regardless of the mechanism (risk effects, competitive release, or other), our findings suggest that overfishing of sharks has the potential to trigger trophic cascades on coral reefs and that further declines in shark populations globally should be prevented to protect ecosystem health.

  14. Diet and condition of mesopredators on coral reefs in relation to shark abundance.

    Directory of Open Access Journals (Sweden)

    Shanta C Barley

    Full Text Available Reef sharks may influence the foraging behaviour of mesopredatory teleosts on coral reefs via both risk effects and competitive exclusion. We used a "natural experiment" to test the hypothesis that the loss of sharks on coral reefs can influence the diet and body condition of mesopredatory fishes by comparing two remote, atoll-like reef systems, the Rowley Shoals and the Scott Reefs, in northwestern Australia. The Rowley Shoals are a marine reserve where sharks are abundant, whereas at the Scott Reefs numbers of sharks have been reduced by centuries of targeted fishing. On reefs where sharks were rare, the gut contents of five species of mesopredatory teleosts largely contained fish while on reefs with abundant sharks, the same mesopredatory species consumed a larger proportion of benthic invertebrates. These measures of diet were correlated with changes in body condition, such that the condition of mesopredatory teleosts was significantly poorer on reefs with higher shark abundance. Condition was defined as body weight, height and width for a given length and also estimated via several indices of condition. Due to the nature of natural experiments, alternative explanations cannot be discounted. However, the results were consistent with the hypothesis that loss of sharks may influence the diet and condition of mesopredators and by association, their fecundity and trophic role. Regardless of the mechanism (risk effects, competitive release, or other, our findings suggest that overfishing of sharks has the potential to trigger trophic cascades on coral reefs and that further declines in shark populations globally should be prevented to protect ecosystem health.

  15. The relative importance of pollinator abundance and species richness for the temporal variance of pollination services.

    Science.gov (United States)

    Genung, Mark A; Fox, Jeremy; Williams, Neal M; Kremen, Claire; Ascher, John; Gibbs, Jason; Winfree, Rachael

    2017-07-01

    The relationship between biodiversity and the stability of ecosystem function is a fundamental question in community ecology, and hundreds of experiments have shown a positive relationship between species richness and the stability of ecosystem function. However, these experiments have rarely accounted for common ecological patterns, most notably skewed species abundance distributions and non-random extinction risks, making it difficult to know whether experimental results can be scaled up to larger, less manipulated systems. In contrast with the prolific body of experimental research, few studies have examined how species richness affects the stability of ecosystem services at more realistic, landscape scales. The paucity of these studies is due in part to a lack of analytical methods that are suitable for the correlative structure of ecological data. A recently developed method, based on the Price equation from evolutionary biology, helps resolve this knowledge gap by partitioning the effect of biodiversity into three components: richness, composition, and abundance. Here, we build on previous work and present the first derivation of the Price equation suitable for analyzing temporal variance of ecosystem services. We applied our new derivation to understand the temporal variance of crop pollination services in two study systems (watermelon and blueberry) in the mid-Atlantic United States. In both systems, but especially in the watermelon system, the stronger driver of temporal variance of ecosystem services was fluctuations in the abundance of common bee species, which were present at nearly all sites regardless of species richness. In contrast, temporal variance of ecosystem services was less affected by differences in species richness, because lost and gained species were rare. Thus, the findings from our more realistic landscapes differ qualitatively from the findings of biodiversity-stability experiments. © 2017 by the Ecological Society of America.

  16. Distribution and relative abundance of large whales in a former whaling ground off eastern South America

    Directory of Open Access Journals (Sweden)

    Artur Andriolo

    2010-10-01

    Full Text Available Ship-based sighting surveys for cetaceans were conducted in the former whaling ground off the northeastern coast of Brazil. The cruises took place in winter and spring of 1998-2001 with the objectives of investigating current distribution and abundance of cetaceans, particularly large whale species taken during whaling. In 1998 the survey were conducted between the parallels 5°30'W and 9°S and the 200 m isobath and the meridian 033°W. A total of about 3,100 nm were surveyed between 1998 and 2001 Surveys were conducted using line transect methods from about 5-10°S, and from the coast to 33°W. A total of 151 sightings (203 individuals of large whales were recorded on effort. The Antarctic minke whale - Balaenoptera bonaerensis (Burmeister, 1867 was the most frequently sighted species (97 groups/132 individuals; Sighting Rate [SR] = 0.031 groups/nm, being recorded only in offshore waters. Density gradually increased from August to October. Minke whales were distributed throughout the area, both to the north and the south of former whaling ground. Sighting data indicate this is the most abundant species, particularly in the area beyond the continental shelf break. Breeding behavior was observed for Antarctic minke whales, but few groups containing calves were recorded (4.3% of the groups sighted on effort. Three other large whale species were recorded in low numbers: the Bryde's whale - Balaenoptera edeni (Anderson, 1879¹; the sei whale, B. borealis (Lesson, 1828, and the sperm, Physeter macrocephalus (Linnaeus, 1758. Sei, Bryde and sperm whales were regularly caught during whaling operations, but are rare in the area, suggesting they were depleted by whaling and have yet to recover to their pre-explotation abundance. In contrast, minke whales are abundant in this area, suggesting that either they were not substantially depleted, or that they have recovered rapidly. Blue whale, Balaenoptera musculus (Linnaeus, 1758, and fin whale, B. physalus

  17. Transcript Abundance of Photorhabdus Insect-Related (Pir Toxin in Manduca sexta and Galleria mellonella Infections

    Directory of Open Access Journals (Sweden)

    Anaïs Castagnola

    2016-09-01

    Full Text Available In this study, we assessed pirAB toxin transcription in Photorhabdus luminescens laumondii (strain TT01 (Enterobacteriaceae by comparing mRNA abundance under in vivo and in vitro conditions. In vivo assays considered both natural and forced infections with two lepidopteran hosts: Galleria mellonella and Manduca sexta. Three portals of entry were utilized for the forced infection assays: (a integument; (b the digestive route (via mouth and anus; and (c the tracheal route (via spiracles. We also assessed plu4093-2 transcription during the course of a natural infection; this is when the bacteria are delivered by Heterorhabditis bacteriophora nematodes. Transcript abundance in G. mellonella was higher than in M. sexta at two of the observed time points: 15 and 18 h. Expression of pirAB plu4093-2 reached above endogenous control levels at 22 h in G. mellonella but not in M. sexta. Overall, pirAB plu4093-2 transcripts were not as highly expressed in M. sexta as in G. mellonella, from 15 to 22 h. This is the first study to directly compare pirAB plu4093-2 toxin transcript production considering different portals of entry.

  18. Bacterial pathogen gene abundance and relation to recreational water quality at seven Great Lakes beaches.

    Science.gov (United States)

    Oster, Ryan J; Wijesinghe, Rasanthi U; Haack, Sheridan K; Fogarty, Lisa R; Tucker, Taaja R; Riley, Stephen C

    2014-12-16

    Quantitative assessment of bacterial pathogens, their geographic variability, and distribution in various matrices at Great Lakes beaches are limited. Quantitative PCR (qPCR) was used to test for genes from E. coli O157:H7 (eaeO157), shiga-toxin producing E. coli (stx2), Campylobacter jejuni (mapA), Shigella spp. (ipaH), and a Salmonella enterica-specific (SE) DNA sequence at seven Great Lakes beaches, in algae, water, and sediment. Overall, detection frequencies were mapA>stx2>ipaH>SE>eaeO157. Results were highly variable among beaches and matrices; some correlations with environmental conditions were observed for mapA, stx2, and ipaH detections. Beach seasonal mean mapA abundance in water was correlated with beach seasonal mean log10 E. coli concentration. At one beach, stx2 gene abundance was positively correlated with concurrent daily E. coli concentrations. Concentration distributions for stx2, ipaH, and mapA within algae, sediment, and water were statistically different (Non-Detect and Data Analysis in R). Assuming 10, 50, or 100% of gene copies represented viable and presumably infective cells, a quantitative microbial risk assessment tool developed by Michigan State University indicated a moderate probability of illness for Campylobacter jejuni at the study beaches, especially where recreational water quality criteria were exceeded. Pathogen gene quantification may be useful for beach water quality management.

  19. pH-Free Measurement of Relative Acidities, Including Isotope Effects.

    Science.gov (United States)

    Perrin, Charles L

    2017-01-01

    A powerful pH-free multicomponent NMR titration method can measure relative acidities, even of closely related compounds, with excellent accuracy. The history of the method is presented, along with details of its implementation and a comparison with earlier NMR titrations using a pH electrode. Many of its areas of applicability are described, especially equilibrium isotope effects. The advantages of the method, some practical considerations, and potential pitfalls are considered. © 2017 Elsevier Inc. All rights reserved.

  20. Golden alga presence and abundance are inversely related to salinity in a high-salinity river ecosystem, Pecos River, USA

    Science.gov (United States)

    Israël, Natascha M.D.; VanLandeghem, Matthew M.; Denny, Shawn; Ingle, John; Patino, Reynaldo

    2014-01-01

    Prymnesium parvum (golden alga, GA) is a toxigenic harmful alga native to marine ecosystems that has also affected brackish inland waters. The first toxic bloom of GA in the western hemisphere occurred in the Pecos River, one of the saltiest rivers in North America. Environmental factors (water quality) associated with GA occurrence in this basin, however, have not been examined. Water quality and GA presence and abundance were determined at eight sites in the Pecos River basin with or without prior history of toxic blooms. Sampling was conducted monthly from January 2012 to July 2013. Specific conductance (salinity) varied spatiotemporally between 4408 and 73,786 mS/cm. Results of graphical, principal component (PCA), and zero-inflated Poisson (ZIP) regression analyses indicated that the incidence and abundance of GA are reduced as salinity increases spatiotemporally. LOWESS regression and correlation analyses of archived data for specific conductance and GA abundance at one of the study sites retrospectively confirmed the negative association between these variables. Results of PCA also suggested that at <15,000 mS/cm, GA was present at a relatively wide range of nutrient (nitrogen and phosphorus) concentrations whereas at higher salinity, GA was observed only at mid-to-high nutrient levels. Generally consistent with earlier studies, results of ZIP regression indicated that GA presence is positively associated with organic phosphorus and in samples where GA is present, GA abundance is positively associated with organic nitrogen and negatively associated with inorganic nitrogen. This is the first report of an inverse relation between salinity and GA presence and abundance in riverine waters and of interaction effects of salinity and nutrients in the field. These observations contribute to a more complete understanding of environmental conditions that influence GA distribution in inland waters.

  1. Studies of osteoporosis in Singapore using isotope related technique

    International Nuclear Information System (INIS)

    Bose, K.; Goh, J.; Lee Soon Tai; Shamal Das De

    1996-01-01

    The main objectives of this study will be to determine the bone density in selected populations for the purposes of i)determining the age of peak bone mass in each study group and ii)quantifying the differences in bone density as functions of the age and sex of persons in the study group as well as quantifying the differences between study groups in different countries. Normal healthy subjects of both sexes across the age range of 15-50 will be recruited for this programme. There will be at least 15 subjects in each 5 year age range (i.e. a total of 105 subjects of each sex). The subjects will be of urban residency. The project will take a maximum of five years. Volunteers will be recruited from the hospital personnel and their friends and relatives. The subjects will be healthy individuals with no history of fractures and they should not be on any medication which may affect the bone density. A questionnaire regarding their lifestyle factors such as exercise, coffee/tea/alcohol intake and medication be filled. The subjects will also have X-rays of the dorsolumbar spine taken to ascertain the absence of scoliosis or crush fractures. Bone mineral density will be measured by dual energy X-ray absorptiometry using a Norland XR-26 bone densitometer. The BMD in the L2-L4 region of the lumbar spine and right hip which includes the femoral neck, trochanter and Ward's triangle will be scanned. Body composition will also be determined by doing a whole body scan on the subjects. Autopsy samples of rib bones from healthy accident victims in the age range 20-50 years will be obtained and the biomechanical strength of these bones will be tested. Biopsy specimens of the iliac crest will also be obtained to study the differences in trace element composition between osteoporotic patients and controls. (author)

  2. System and method for high precision isotope ratio destructive analysis

    Science.gov (United States)

    Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

    2013-07-02

    A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

  3. Utilizing individual fish biomass and relative abundance models to map environmental niche associations of adult and juvenile targeted fishes.

    Science.gov (United States)

    Galaiduk, Ronen; Radford, Ben T; Harvey, Euan S

    2018-06-21

    Many fishes undergo ontogenetic habitat shifts to meet their energy and resource needs as they grow. Habitat resource partitioning and patterns of habitat connectivity between conspecific fishes at different life-history stages is a significant knowledge gap. Species distribution models were used to examine patterns in the relative abundance, individual biomass estimates and environmental niche associations of different life stages of three iconic West Australian fishes. Continuous predictive maps describing the spatial distribution of abundance and individual biomass of the study species were created as well predictive hotspot maps that identify possible areas for aggregation of individuals of similar life stages of multiple species (i.e. spawning grounds, fisheries refugia or nursery areas). The models and maps indicate that processes driving the abundance patterns could be different from the body size associated demographic processes throughout an individual's life cycle. Incorporating life-history in the spatially explicit management plans can ensure that critical habitat of the vulnerable stages (e.g. juvenile fish, spawning stock) is included within proposed protected areas and can enhance connectivity between various functional areas (e.g. nursery areas and adult populations) which, in turn, can improve the abundance of targeted species as well as other fish species relying on healthy ecosystem functioning.

  4. Distribution and abundance of juvenile demersal fishes in relation to summer hypoxia and other environmental variables in coastal Oregon, USA

    Science.gov (United States)

    Sobocinski, Kathryn L.; Ciannelli, Lorenzo; Wakefield, W. Waldo; Yergey, Matthew E.; Johnson-Colegrove, Angela

    2018-05-01

    The juvenile demersal fish assemblage along the Pacific Northwest coast has received little attention relative to adult life history stages since pioneering work in the 1970s. Increasing severity of hypoxia along the Oregon coast in recent years has prompted investigations into the response of biota in this region. We used summer data (2008-2013) from a beam trawl survey targeting juvenile demersal fishes in soft-bottom habitats along the Oregon coast to describe patterns of distribution and abundance at fixed sampling stations (from 30 m to 100 m depth). We relate the assemblage and abundance of the common species to environmental variables and analyze condition of recently settled fish (improve our understanding of this community, especially in light of changing environmental drivers such as decreasing pH, warming water, and episodic periods of low dissolved oxygen coinciding with settlement for many species.

  5. Evaluation of alternative age-based methods for estimating relative abundance from survey data in relation to assessment models

    DEFF Research Database (Denmark)

    Berg, Casper Willestofte; Nielsen, Anders; Kristensen, Kasper

    2014-01-01

    Indices of abundance from fishery-independent trawl surveys constitute an important source of information for many fish stock assessments. Indices are often calculated using area stratified sample means on age-disaggregated data, and finally treated in stock assessment models as independent...... observations. We evaluate a series of alternative methods for calculating indices of abundance from trawl survey data (delta-lognormal, delta-gamma, and Tweedie using Generalized Additive Models) as well as different error structures for these indices when used as input in an age-based stock assessment model...... the different indices produced. The stratified mean method is found much more imprecise than the alternatives based on GAMs, which are found to be similar. Having time-varying index variances is found to be of minor importance, whereas the independence assumption is not only violated but has significant impact...

  6. Data-poor management of African lion hunting using a relative index of abundance.

    Science.gov (United States)

    Edwards, Charles T T; Bunnefeld, Nils; Balme, Guy A; Milner-Gulland, E J

    2014-01-07

    Sustainable management of terrestrial hunting requires managers to set quotas restricting offtake. This often takes place in the absence of reliable information on the population size, and as a consequence, quotas are set in an arbitrary fashion, leading to population decline and revenue loss. In this investigation, we show how an indirect measure of abundance can be used to set quotas in a sustainable manner, even in the absence of information on population size. Focusing on lion hunting in Africa, we developed a simple algorithm to convert changes in the number of safari days required to kill a lion into a quota for the following year. This was tested against a simulation model of population dynamics, accounting for uncertainties in demography, observation, and implementation. Results showed it to reliably set sustainable quotas despite these uncertainties, providing a robust foundation for the conservation of hunted species.

  7. Bacterial pathogen gene abundance and relation to recreational water quality at seven Great Lakes beaches

    Science.gov (United States)

    Oster, Ryan J.; Wijesinghe, Rasanthi U.; Fogarty, Lisa Reynolds; Haack, Sheridan K.; Fogarty, Lisa R.; Tucker, Taaja R.; Riley, Stephen

    2014-01-01

    Quantitative assessment of bacterial pathogens, their geographic variability, and distribution in various matrices at Great Lakes beaches are limited. Quantitative PCR (qPCR) was used to test for genes from E. coli O157:H7 (eaeO157), shiga-toxin producing E. coli (stx2), Campylobacter jejuni (mapA), Shigella spp. (ipaH), and a Salmonella enterica-specific (SE) DNA sequence at seven Great Lakes beaches, in algae, water, and sediment. Overall, detection frequencies were mapA>stx2>ipaH>SE>eaeO157. Results were highly variable among beaches and matrices; some correlations with environmental conditions were observed for mapA, stx2, and ipaH detections. Beach seasonal mean mapA abundance in water was correlated with beach seasonal mean log10E. coli concentration. At one beach, stx2 gene abundance was positively correlated with concurrent daily E. coli concentrations. Concentration distributions for stx2, ipaH, and mapA within algae, sediment, and water were statistically different (Non-Detect and Data Analysis in R). Assuming 10, 50, or 100% of gene copies represented viable and presumably infective cells, a quantitative microbial risk assessment tool developed by Michigan State University indicated a moderate probability of illness for Campylobacter jejuni at the study beaches, especially where recreational water quality criteria were exceeded. Pathogen gene quantification may be useful for beach water quality management.

  8. Increase in soil stable carbon isotope ratio relates to loss of organic carbon: results from five long-term bare fallow experiments.

    Science.gov (United States)

    Menichetti, Lorenzo; Houot, Sabine; van Oort, Folkert; Kätterer, Thomas; Christensen, Bent T; Chenu, Claire; Barré, Pierre; Vasilyeva, Nadezda A; Ekblad, Alf

    2015-03-01

    Changes in the (12)C/(13)C ratio (expressed as δ(13)C) of soil organic C (SOC) has been observed over long time scales and with depth in soil profiles. The changes are ascribed to the different reaction kinetics of (12)C and (13)C isotopes and the different isotopic composition of various SOC pool components. However, experimental verification of the subtle isotopic shifts associated with SOC turnover under field conditions is scarce. We determined δ(13)C and SOC in soil sampled during 1929-2009 in the Ap-horizon of five European long-term bare fallow experiments kept without C inputs for 27-80 years and covering a latitudinal range of 11°. The bare fallow soils lost 33-65% of their initial SOC content and showed a mean annual δ(13)C increase of 0.008-0.024‰. The (13)C enrichment could be related empirically to SOC losses by a Rayleigh distillation equation. A more complex mechanistic relationship was also examined. The overall estimate of the fractionation coefficient (ε) was -1.2 ± 0.3‰. This coefficient represents an important input to studies of long-term SOC dynamics in agricultural soils that are based on variations in (13)C natural abundance. The variance of ε may be ascribed to site characteristics not disclosed in our study, but the very similar kinetics measured across our five experimental sites suggest that overall site-specific factors (including climate) had a marginal influence and that it may be possible to isolate a general mechanism causing the enrichment, although pre-fallow land use may have some impact on isotope abundance and fractionation.

  9. 454 pyrosequencing to describe microbial eukaryotic community composition, diversity and relative abundance: a test for marine haptophytes.

    Directory of Open Access Journals (Sweden)

    Elianne Egge

    Full Text Available Next generation sequencing of ribosomal DNA is increasingly used to assess the diversity and structure of microbial communities. Here we test the ability of 454 pyrosequencing to detect the number of species present, and assess the relative abundance in terms of cell numbers and biomass of protists in the phylum Haptophyta. We used a mock community consisting of equal number of cells of 11 haptophyte species and compared targeting DNA and RNA/cDNA, and two different V4 SSU rDNA haptophyte-biased primer pairs. Further, we tested four different bioinformatic filtering methods to reduce errors in the resulting sequence dataset. With sequencing depth of 11000-20000 reads and targeting cDNA with Haptophyta specific primers Hap454 we detected all 11 species. A rarefaction analysis of expected number of species recovered as a function of sampling depth suggested that minimum 1400 reads were required here to recover all species in the mock community. Relative read abundance did not correlate to relative cell numbers. Although the species represented with the largest biomass was also proportionally most abundant among the reads, there was generally a weak correlation between proportional read abundance and proportional biomass of the different species, both with DNA and cDNA as template. The 454 sequencing generated considerable spurious diversity, and more with cDNA than DNA as template. With initial filtering based only on match with barcode and primer we observed 100-fold more operational taxonomic units (OTUs at 99% similarity than the number of species present in the mock community. Filtering based on quality scores, or denoising with PyroNoise resulted in ten times more OTU99% than the number of species. Denoising with AmpliconNoise reduced the number of OTU99% to match the number of species present in the mock community. Based on our analyses, we propose a strategy to more accurately depict haptophyte diversity using 454 pyrosequencing.

  10. 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)

  11. Comparing relative abundance, lengths, and habitat of temperate reef fishes using simultaneous underwater visual census, video, and trap sampling

    KAUST Repository

    Bacheler, NM

    2017-04-28

    Unbiased counts of individuals or species are often impossible given the prevalence of cryptic or mobile species. We used 77 simultaneous multi-gear deployments to make inferences about relative abundance, diversity, length composition, and habitat of the reef fish community along the southeastern US Atlantic coast. In total, 117 taxa were observed by underwater visual census (UVC), stationary video, and chevron fish traps, with more taxa being observed by UVC (100) than video (82) or traps (20). Frequency of occurrence of focal species was similar among all sampling approaches for tomtate Haemulon aurolineatum and black sea bass Centropristis striata, higher for UVC and video compared to traps for red snapper Lutjanus campechanus, vermilion snapper Rhomboplites aurorubens, and gray triggerfish Balistes capriscus, and higher for UVC compared to video or traps for gray snapper L. griseus and lionfish Pterois spp. For 6 of 7 focal species, correlations of relative abundance among gears were strongest between UVC and video, but there was substantial variability among species. The number of recorded species between UVC and video was correlated (ρ = 0.59), but relationships between traps and the other 2 methods were weaker. Lengths of fish visually estimated by UVC were similar to lengths of fish caught in traps, as were habitat characterizations from UVC and video. No gear provided a complete census for any species in our study, suggesting that analytical methods accounting for imperfect detection are necessary to make unbiased inferences about fish abundance.

  12. Mosquitoes of the rice agroecosystem of Malaysia: species composition and their abundance in relation to rice farming

    International Nuclear Information System (INIS)

    Abu Hassan Ahmad; Che Salmah Md Rawi

    2002-01-01

    Mosquito abundance in relation to rice farming was studied in the Muda and the Kerian Irrigation Schemes. Mosquito larvae were collected using dippers for several growing seasons. Adult mosquitoes were collected by using human bait and cow bait and net trap at nights. Culex, Mansonia and Anopheles were the three genera of mosquito found in the rice agroecosystem. Four species of Mansonia were found biting on human bait. Culex mosquitoes were caught biting on human and cow baits. Culex tritaeniorhynchus, C pseudovishnui, C vishnui, C gelidus and C bitaeniorhynchus were the most common Culex mosquitoes found. Anoheles sinensis and A. peditaeniatus were the most dominant panopheline mosquitoes. High abundance of larvae and adult mosquitoes were observed during ploughing, planting, and tillering stages of rice farming. (Author)

  13. Relative rate study of the kinetic isotope effect in the 13CH3D + Cl reaction

    DEFF Research Database (Denmark)

    Joelsson, Lars Magnus Torvald; Forecast, Roslyn; Schmidt, Johan Albrecht

    2014-01-01

    The 13CH3D/12CH4kinetic isotope effect, α13CH3D, of CH4 + Cl is determined for the first time, using the relative rate technique and Fourier transform infrared (FTIR) spectroscopy. α13CH3D is found to be 1.60 ± 0.04. In addition, a quantum chemistry/transition state theory model with tunneling...

  14. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2005-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. (author). 52 refs., 11 figs., 2 tabs

  15. Relating tropical ocean clouds to moist processes using water vapor isotope measurements

    Directory of Open Access Journals (Sweden)

    J. Lee

    2011-01-01

    Full Text Available We examine the co-variations of tropospheric water vapor, its isotopic composition and cloud types and relate these distributions to tropospheric mixing and distillation models using satellite observations from the Aura Tropospheric Emission Spectrometer (TES over the summertime tropical ocean. Interpretation of these process distributions must take into account the sensitivity of the TES isotope and water vapor measurements to variations in cloud, water, and temperature amount. Consequently, comparisons are made between cloud-types based on the International Satellite Cloud Climatology Project (ISSCP classification; these are clear sky, non-precipitating (e.g., cumulus, boundary layer (e.g., stratocumulus, and precipitating clouds (e.g. regions of deep convection. In general, we find that the free tropospheric vapor over tropical oceans does not strictly follow a Rayleigh model in which air parcels become dry and isotopically depleted through condensation. Instead, mixing processes related to convection as well as subsidence, and re-evaporation of rainfall associated with organized deep convection all play significant roles in controlling the water vapor distribution. The relative role of these moisture processes are examined for different tropical oceanic regions.

  16. The 13C-pocket structure in AGB models: constraints from zirconium isotope abundances in single mainstream SiC grains

    International Nuclear Information System (INIS)

    Liu, Nan; Davis, Andrew M.; Pellin, Michael J.; Gallino, Roberto; Bisterzo, Sara; Savina, Michael R.

    2014-01-01

    We present postprocess asymptotic giant branch (AGB) nucleosynthesis models with different 13 C-pocket internal structures to better explain zirconium isotope measurements in mainstream presolar SiC grains by Nicolussi et al. and Barzyk et al. We show that higher-than-solar 92 Zr/ 94 Zr ratios can be predicted by adopting a 13 C-pocket with a flat 13 C profile, instead of the previous decreasing-with-depth 13 C profile. The improved agreement between grain data for zirconium isotopes and AGB models provides additional support for a recent proposal of a flat 13 C profile based on barium isotopes in mainstream SiC grains by Liu et al.

  17. Actinide isotopic analysis systems

    International Nuclear Information System (INIS)

    Koenig, Z.M.; Ruhter, W.D.; Gunnink, R.

    1990-01-01

    This manual provides instructions and procedures for using the Lawrence Livermore National Laboratory's two-detector actinide isotope analysis system to measure plutonium samples with other possible actinides (including uranium, americium, and neptunium) by gamma-ray spectrometry. The computer program that controls the system and analyzes the gamma-ray spectral data is driven by a menu of one-, two-, or three-letter options chosen by the operator. Provided in this manual are descriptions of these options and their functions, plus detailed instructions (operator dialog) for choosing among the options. Also provided are general instructions for calibrating the actinide isotropic analysis system and for monitoring its performance. The inventory measurement of a sample's total plutonium and other actinides content is determined by two nondestructive measurements. One is a calorimetry measurement of the sample's heat or power output, and the other is a gamma-ray spectrometry measurement of its relative isotopic abundances. The isotopic measurements needed to interpret the observed calorimetric power measurement are the relative abundances of various plutonium and uranium isotopes and americium-241. The actinide analysis system carries out these measurements. 8 figs

  18. Considerations related to the deuterium-depleted water isotopic analysis for an industrial production pilot plant

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru; Irimescu, Rodica

    2000-01-01

    In the last few years, there is a major interest related to the use of Deuterium Depleted Water (DDW) for biological and medical purposes. Therefore, a production installation for DDW was developed and now, it is working in our Institute. The deuterium isotopic concentration for the final product is in the 10 - 40 ppm D / (D + H) range depending on customers' requirements. In order to control and manage the production process and also to validate the final product, a special procedure for deuterium content measurement for DDW by Isotopic Ratio Mass Spectrometry was developed. The main instrumentation is a MAT 250 IRMS with a hydrogen preparation line based on the zinc reduction process. The first concern regarding the analysis procedure for these water samples with very low deuterium concentration has been related to the preparation of an internal standard with a D / (D + H) isotopic value in the measurement range. For this raison, a distinct procedure was developed and applied, so that starting to the well-known VSMOW standard and so, a sequence of 12 samples with decreasing deuterium content was obtained. These samples were measured and 3 / 2 ratio mass signals versus 2 mass signal were plotted and statistically analyzed. Obviously, for each measurement, a H 3+ correction factor was calculated and applied, as a results of an entire statistically elimination procedure and by extrapolation of the linear curve plotted, a value for the primary DDW was determined. Other important problem related to deuterium content determination was to minimize the H 3+ factor correction. As the deuterium content is very low the contribution of this factor to the 3 mass signal becomes very important. Therefore, special operations were developed, considering the behaviour of linear dependence between 3 / 2 mass signal versus 2 mass signal in the lower part. Finally, special attention was given to estimate the lower isotopic concentration analysis limit. (authors)

  19. LDL receptor-related protein 1 regulates the abundance of diverse cell-signaling proteins in the plasma membrane proteome.

    Science.gov (United States)

    Gaultier, Alban; Simon, Gabriel; Niessen, Sherry; Dix, Melissa; Takimoto, Shinako; Cravatt, Benjamin F; Gonias, Steven L

    2010-12-03

    LDL receptor-related protein 1 (LRP1) is an endocytic receptor, reported to regulate the abundance of other receptors in the plasma membrane, including uPAR and tissue factor. The goal of this study was to identify novel plasma membrane proteins, involved in cell-signaling, that are regulated by LRP1. Membrane protein ectodomains were prepared from RAW 264.7 cells in which LRP1 was silenced and control cells using protease K. Peptides were identified by LC-MS/MS. By analysis of spectral counts, 31 transmembrane and secreted proteins were regulated in abundance at least 2-fold when LRP1 was silenced. Validation studies confirmed that semaphorin4D (Sema4D), plexin domain-containing protein-1 (Plxdc1), and neuropilin-1 were more abundant in the membranes of LRP1 gene-silenced cells. Regulation of Plxdc1 by LRP1 was confirmed in CHO cells, as a second model system. Plxdc1 coimmunoprecipitated with LRP1 from extracts of RAW 264.7 cells and mouse liver. Although Sema4D did not coimmunoprecipitate with LRP1, the cell-surface level of Sema4D was increased by RAP, which binds to LRP1 and inhibits binding of other ligands. These studies identify Plxdc1, Sema4D, and neuropilin-1 as novel LRP1-regulated cell-signaling proteins. Overall, LRP1 emerges as a generalized regulator of the plasma membrane proteome.

  20. Tree hole mosquito species composition and relative abundances differ between urban and adjacent forest habitats in northwestern Argentina.

    Science.gov (United States)

    Mangudo, C; Aparicio, J P; Rossi, G C; Gleiser, R M

    2018-04-01

    Water-holding tree holes are main larval habitats for many pathogen vectors, especially mosquitoes (Diptera: Culicidae). Along 3 years, the diversity and composition of mosquito species in tree holes of two neighbouring but completely different environments, a city and its adjacent forest, were compared using generalized linear mixed models, PERMANOVA, SIMPER and species association indexes. The city area (Northwest Argentina) is highly relevant epidemiologically due to the presence of Aedes aegypti L. (main dengue vector) and occurrence of dengue outbreaks; the Yungas rainforests are highly biologically diverse. In total seven mosquito species were recorded, in descending order of abundance: Ae. aegypti, Haemagogus spegazzinii Brèthes, Sabethes purpureus (Theobald), Toxorhynchites guadeloupensis Dyar and Knab, Aedes terrens Walker, Haemagogus leucocelaenus Dyar & Shannon and Sabethes petrocchiae (Shannon and Del Ponte). The seven mosquito species were recorded in both city sites and forested areas; however, their mosquito communities significantly diverged because of marked differences in the frequency and relative abundance of some species: Tx. guadeloupensis and Ae. aegypti were significantly more abundant in forest and urban areas, respectively. Positive significant associations were detected between Ae. aegypti, Hg. spegazzinii and Hg. leucocelaenus. The combined presence of Ae. aegypti, Haemagogus and Sabethes in the area also highlight a potential risk of yellow fever epidemics. Overall results show an impoverished tree hole mosquito fauna in urban environments, reflecting negative effects of urbanization on mosquito diversity.

  1. Long-term prairie falcon population changes in relation to prey abundance, weather, land uses, and habitat conditions

    Science.gov (United States)

    Steenhof, Karen; Kochert, Michael N.; Carpenter, L.B.; Lehman, Robert N.

    1999-01-01

    We studied a nesting population of Prairie Falcons (Falco mexicanus) in the Snake River Birds of Prey National Conservation Area (NCA) from 1974-1997 to identify factors that influence abundance and reproduction. Our sampling period included two major droughts and associated crashes in Townsend's ground squirrel (Spermophilus townsendii) populations. The number of Prairie Falcon pairs found on long-term survey segments declined significantly from 1976-1997. Early declines were most severe at the eastern end of the NCA, where fires and agriculture have changed native shrubsteppe habitat. More recent declines occurred in the portion of canyon near the Orchard Training Area (OTA), where the Idaho Army National Guard conducts artillery firing and tank maneuvers. Overall Prairie Falcon reproductive rates were tied closely to annual indexes of ground squirrel abundance, but precipitation before and during the breeding season was related inversely to some measures of reproduction. Most reproductive parameters showed no significant trends over time, but during the 1990s, nesting success and productivity were lower in the stretch of canyon near the OTA than in adjacent areas. Extensive shrub loss, by itself, did not explain the pattern of declines in abundance and reproduction that we observed. Recent military training activities likely have interacted with fire and livestock grazing to create less than favorable foraging opportunities for Prairie Falcons in a large part of the NCA. To maintain Prairie Falcon populations in the NCA, managers should suppress wildfires, restore native plant communities, and regulate potentially incompatible land uses.

  2. Characterization and relative quantification of phospholipids based on methylation and stable isotopic labeling[S

    Science.gov (United States)

    Cai, Tanxi; Shu, Qingbo; Liu, Peibin; Niu, Lili; Guo, Xiaojing; Ding, Xiang; Xue, Peng; Xie, Zhensheng; Wang, Jifeng; Zhu, Nali; Wu, Peng; Niu, Lili; Yang, Fuquan

    2016-01-01

    Phospholipids (PLs), one of the lipid categories, are not only the primary building blocks of cellular membranes, but also can be split to produce products that function as second messengers in signal transduction and play a pivotal role in numerous cellular processes, including cell growth, survival, and motility. Here, we present an integrated novel method that combines a fast and robust TMS-diazomethane-based phosphate derivatization and isotopic labeling strategy, which enables simultaneous profiling and relative quantification of PLs from biological samples. Our results showed that phosphate methylation allows fast and sensitive identification of the six major PL classes, including their lysophospholipid counterparts, under positive ionization mode. The isotopic labeling of endogenous PLs was achieved by deuterated diazomethane, which was generated through acid-catalyzed hydrogen/deuterium (H/D) exchange and methanolysis of TMS-diazomethane during the process of phosphate derivatization. The measured H/D ratios of unlabeled and labeled PLs, which were mixed in known proportions, indicated that the isotopic labeling strategy is capable of providing relative quantitation with adequate accuracy, reproducibility, and a coefficient of variation of 9.1%, on average. This novel method offers unique advantages over existing approaches and presents a powerful tool for research of PL metabolism and signaling. PMID:26733148

  3. Selective conversion of plasma glucose into CO2 by Saccharomyces cerevisiae for the measurement of C-13 abundance by isotope ratio mass spectrometry : proof of principle

    NARCIS (Netherlands)

    Rembacz, Krzysztof P.; Faber, Klaas Nico; Stellaard, Frans

    2007-01-01

    To study carbohydrate digestion and glucose absorption, time-dependent C-13 enrichment in plasma glucose is measured after oral administration of naturally occurring C-13-enriched carbohydrates. The isotope enrichment of the administered carbohydrate is low (APE <0.1%) and plasma C-13 glucose

  4. The use of electrolysis for accurate delta O-17 and delta O-18 isotope measurements in water

    NARCIS (Netherlands)

    Meijer, HAJ; Li, WJ

    1998-01-01

    We present a new system to measure the relative isotopic abundances of both rare isotopes of oxygen in water. Using electrolysis with CuSO4 as electrolyte, water is transformed into oxygen gas. This gas is subsequently analyzed with a standard Isotope Ratio Mass Spectrometer. We investigated the

  5. 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.

  6. The centenary of the discovery of isotopes

    International Nuclear Information System (INIS)

    Soulie, Edgar

    2013-01-01

    This article recalls works performed by different scientists (Marckwald and Keetman, Stromholm and Svedberg, Soddy, Thompson, Aston) which resulted in the observation and identification of the existence of isotopes. The author also recalls various works related to mechanisms of production of isotopes, the discovery of uranium fission and the principle of chain reaction. The author notably evokes French scientists involved in the development of mass spectroscopy and in the research and applications on isotopes within the CEA after the Second World War. A bibliography of article and books published by one of them, Etienne Roth, is provided. References deal with nuclear applications of chemical engineering (heavy water and its production, chemical processes in fission reactors, tritium extraction and enrichment), isotopic fractioning and physical-chemical processes, mass spectrometry and isotopic analysis, isotopic geochemistry (on 07;Earth, search for deuterium in moon rocks and their consequences), first dating and the Oklo phenomenon, radioactive dating, water and climate (isotopic hydrology, isotopes and hailstone formation, the atmosphere), and miscellaneous scientific fields (nuclear measurements and radioactivity, isotopic abundances and atomic weight, isotopic separation and use of steady isotopes)

  7. Relative Abundance and Diversity of Bacterial Methanotrophs at the Oxic?Anoxic Interface of the Congo Deep-Sea Fan

    OpenAIRE

    Bessette, Sandrine; Moalic, Yann; Gautey, S?bastien; Lesongeur, Fran?oise; Godfroy, Anne; Toffin, Laurent

    2017-01-01

    Sitting at ∼5,000 m water depth on the Congo-Angola margin and ∼760 km offshore of the West African coast, the recent lobe complex of the Congo deep-sea fan receives large amounts of fluvial sediments (3–5% organic carbon). This organic-rich sedimentation area harbors habitats with chemosynthetic communities similar to those of cold seeps. In this study, we investigated relative abundance, diversity and distribution of aerobic methane-oxidizing bacteria (MOB) communities at the oxic–anoxic in...

  8. Diffusion related isotopic fractionation effects with one-dimensional advective–dispersive transport

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Bruce S. [Civil Engineering Department, University of Toronto, 35 St George Street, Toronto, ON M5S 1A4 (Canada); Lollar, Barbara Sherwood [Earth Sciences Department, University of Toronto, 22 Russell Street, Toronto, ON M5S 3B1 (Canada); Passeport, Elodie [Civil Engineering Department, University of Toronto, 35 St George Street, Toronto, ON M5S 1A4 (Canada); Chemical Engineering and Applied Chemistry Department, University of Toronto, 200 College Street, Toronto, ON M5S 3E5 (Canada); Sleep, Brent E., E-mail: sleep@ecf.utoronto.ca [Civil Engineering Department, University of Toronto, 35 St George Street, Toronto, ON M5S 1A4 (Canada)

    2016-04-15

    Aqueous phase diffusion-related isotope fractionation (DRIF) for carbon isotopes was investigated for common groundwater contaminants in systems in which transport could be considered to be one-dimensional. This paper focuses not only on theoretically observable DRIF effects in these systems but introduces the important concept of constraining “observable” DRIF based on constraints imposed by the scale of measurements in the field, and on standard limits of detection and analytical uncertainty. Specifically, constraints for the detection of DRIF were determined in terms of the diffusive fractionation factor, the initial concentration of contaminants (C{sub 0}), the method detection limit (MDL) for isotopic analysis, the transport time, and the ratio of the longitudinal mechanical dispersion coefficient to effective molecular diffusion coefficient (D{sub mech}/D{sub eff}). The results allow a determination of field conditions under which DRIF may be an important factor in the use of stable carbon isotope measurements for evaluation of contaminant transport and transformation for one-dimensional advective–dispersive transport. This study demonstrates that for diffusion-dominated transport of BTEX, MTBE, and chlorinated ethenes, DRIF effects are only detectable for the smaller molar mass compounds such as vinyl chloride for C{sub 0}/MDL ratios of 50 or higher. Much larger C{sub 0}/MDL ratios, corresponding to higher source concentrations or lower detection limits, are necessary for DRIF to be detectable for the higher molar mass compounds. The distance over which DRIF is observable for VC is small (less than 1 m) for a relatively young diffusive plume (< 100 years), and DRIF will not easily be detected by using the conventional sampling approach with “typical” well spacing (at least several meters). With contaminant transport by advection, mechanical dispersion, and molecular diffusion this study suggests that in field sites where D{sub mech}/D{sub eff} is

  9. Diffusion related isotopic fractionation effects with one-dimensional advective–dispersive transport

    International Nuclear Information System (INIS)

    Xu, Bruce S.; Lollar, Barbara Sherwood; Passeport, Elodie; Sleep, Brent E.

    2016-01-01

    Aqueous phase diffusion-related isotope fractionation (DRIF) for carbon isotopes was investigated for common groundwater contaminants in systems in which transport could be considered to be one-dimensional. This paper focuses not only on theoretically observable DRIF effects in these systems but introduces the important concept of constraining “observable” DRIF based on constraints imposed by the scale of measurements in the field, and on standard limits of detection and analytical uncertainty. Specifically, constraints for the detection of DRIF were determined in terms of the diffusive fractionation factor, the initial concentration of contaminants (C_0), the method detection limit (MDL) for isotopic analysis, the transport time, and the ratio of the longitudinal mechanical dispersion coefficient to effective molecular diffusion coefficient (D_m_e_c_h/D_e_f_f). The results allow a determination of field conditions under which DRIF may be an important factor in the use of stable carbon isotope measurements for evaluation of contaminant transport and transformation for one-dimensional advective–dispersive transport. This study demonstrates that for diffusion-dominated transport of BTEX, MTBE, and chlorinated ethenes, DRIF effects are only detectable for the smaller molar mass compounds such as vinyl chloride for C_0/MDL ratios of 50 or higher. Much larger C_0/MDL ratios, corresponding to higher source concentrations or lower detection limits, are necessary for DRIF to be detectable for the higher molar mass compounds. The distance over which DRIF is observable for VC is small (less than 1 m) for a relatively young diffusive plume (< 100 years), and DRIF will not easily be detected by using the conventional sampling approach with “typical” well spacing (at least several meters). With contaminant transport by advection, mechanical dispersion, and molecular diffusion this study suggests that in field sites where D_m_e_c_h/D_e_f_f is larger than 10, DRIF

  10. Reef Sharks Exhibit Site-Fidelity and Higher Relative Abundance in Marine Reserves on the Mesoamerican Barrier Reef

    Science.gov (United States)

    Bond, Mark E.; Babcock, Elizabeth A.; Pikitch, Ellen K.; Abercrombie, Debra L.; Lamb, Norlan F.; Chapman, Demian D.

    2012-01-01

    Carcharhinid sharks can make up a large fraction of the top predators inhabiting tropical marine ecosystems and have declined in many regions due to intense fishing pressure. There is some support for the hypothesis that carcharhinid species that complete their life-cycle within coral reef ecosystems, hereafter referred to as “reef sharks”, are more abundant inside no-take marine reserves due to a reduction in fishing pressure (i.e., they benefit from marine reserves). Key predictions of this hypothesis are that (a) individual reef sharks exhibit high site-fidelity to these protected areas and (b) their relative abundance will generally be higher in these areas compared to fished reefs. To test this hypothesis for the first time in Caribbean coral reef ecosystems we combined acoustic monitoring and baited remote underwater video (BRUV) surveys to measure reef shark site-fidelity and relative abundance, respectively. We focused on the Caribbean reef shark (Carcharhinus perezi), the most common reef shark in the Western Atlantic, at Glover's Reef Marine Reserve (GRMR), Belize. Acoustically tagged sharks (N = 34) were detected throughout the year at this location and exhibited strong site-fidelity. Shark presence or absence on 200 BRUVs deployed at GRMR and three other sites (another reserve site and two fished reefs) showed that the factor “marine reserve” had a significant positive effect on reef shark presence. We rejected environmental factors or site-environment interactions as predominant drivers of this pattern. These results are consistent with the hypothesis that marine reserves can benefit reef shark populations and we suggest new hypotheses to determine the underlying mechanism(s) involved: reduced fishing mortality or enhanced prey availability. PMID:22412965

  11. Wide prevalence of hybridization in two sympatric grasshopper species may be shaped by their relative abundances.

    Science.gov (United States)

    Rohde, Katja; Hau, Yvonne; Weyer, Jessica; Hochkirch, Axel

    2015-09-16

    Hybridization between species is of conservation concern as it might threaten the genetic integrity of species. Anthropogenic factors can alter hybridization dynamics by introducing new potentially hybridizing species or by diminishing barriers to hybridization. This may even affect sympatric species pairs through environmental change, which so far has received little attention. We studied hybridization prevalence and the underlying behavioral mechanisms in two sympatric grasshopper species, a rare specialist (Chorthippus montanus) and a common generalist (Chorthippus parallelus). We conducted a mate choice experiment with constant intraspecific density and varying heterospecific density, i.e. varying relative frequency of both species. Mate choice was frequency-dependent in both species with a higher risk of cross-mating with increasing heterospecific frequency, while conspecific mating increased linearly with increasing conspecific density. This illustrates that reproductive barriers could be altered by environmental change, if the relative frequency of species pairs is affected. Moreover, we performed a microsatellite analysis to detect hybridization in twelve syntopic populations (and four allotopic populations). Hybrids were detected in nearly all syntopic populations with hybridization rates reaching up to 8.9 %. Genetic diversity increased for both species when hybrids were included in the data set, but only in the common species a positive correlation between hybridization rate and genetic diversity was detected. Our study illustrates that the relative frequency of the two species strongly determines the effectiveness of reproductive barriers and that even the more choosy species (Ch. montanus) may face a higher risk of hybridization if population size decreases and its relative frequency becomes low compared to its sister species. The asymmetric mate preferences of both species may lead to quasi-unidirectional gene flow caused by unidirectional

  12. Distribution and relative abundance of anchovies (Clupeiformes-engraulididae in the Sepetiba Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Márcio de Araújo Silva

    2000-01-01

    Full Text Available Distribution and relative abundance of juvenile fish of the family Engraulididae in the Sepetiba Bay, Rio de Janeiro, Brazil was assessed to detect patterns of use of the shallows during their early life cycle. Two yearly cycle (March-1996 to February-1997 and March-1997 to February-1998 were studied by a total of 120 beach net samples at five sites, two of them located in the inner Bay and three in the outer Bay near to the sea limit. Six Engraulididae species were identified in two genera: Anchoa januaria, Anchoa marinii, Anchoa tricolor, Anchoa lyolepis, Anchoviella lepidentostole and Anchoviella brevirostris, mainly juveniles in their early life cycle. A. januaria, A. brevirostris, A. lepidentostole and A. tricolor, in decreasing order, were the top numerical abundant species, while A. tricolor and A. januaria showed the highest weight contribution, amounting approximately to 90% of the total number of fish. Spatially, A. tricolor, A. lyolepis and A. marinii distributed mainly in the outer Bay. A. januaria show higher abundance in the inner Bay, while the species of genera Anchoviella show an ample distribution, without a particular zone of higher occurrence. Seasonally, only A. januaria, A. lepidentostole and A. brevirostris presented a clear pattern of occurrence, peaking in the Autumn.A abundância relativa e distribuição espacial de juvenis de peixes da familia Engraulididae ocorrentes na Baía de Sepetiba, Rio de Janeiro, Brasil, foram estudadas visando determinar os padrões de uso da margem continental durante a fase inicial de vida. Dois ciclos anuais (Março-1996 a Fevereiro-1997 e Março-1997 a Fevereiro-1998 foram investigados através de um total de 120 amostragens de arrastos de praia, distribuídas em 5 locais de coleta na margem continental da Baía, duas delas situadas na zona mais interna e três na zona mais externa e próxima do limite com o mar. Foram identificados 6 espécies de Engraulididae, compreendendo dois g

  13. The use of radioisotopes and low abundance stable isotopes for the study of bioavailability and the metabolism of iron, zinc and copper

    International Nuclear Information System (INIS)

    Aggett, P.J.; Fairweather Tait, S.

    1994-01-01

    The use of whole body counting and imaging with ''area of interest'' counting to monitor the metabolism of zinc in healthy volunteers and patients with coeliac diseases and cirrhosis is described as are studies of interaction between iron and copper. Stable isotopes of iron, copper and zinc have been used to investigate the metabolism of these elements in young infants and have proved useful in assessing the validity of current estimated requirements particularly of iron. Stable isotopes have also been used to improve the classic metabolic balance approach to the study of the homeostasis of zinc in zinc deprived volunteers, and have progressed to studies using plasma kinetic curves of the systemic compartmentation of zinc

  14. Sexual versus Asexual Reproduction: Distinct Outcomes in Relative Abundance of Parthenogenetic Mealybugs following Recent Colonization.

    Science.gov (United States)

    Tabata, Jun; Ichiki, Ryoko T; Tanaka, Hirotaka; Kageyama, Daisuke

    2016-01-01

    Asexual reproduction, including parthenogenesis in which embryos develop within a female without fertilization, is assumed to confer advantages over sexual reproduction, which includes a "cost of males." Sexual reproduction largely predominates in animals, however, indicating that this cost is outweighed by the genetic and/or ecological benefits of sexuality, including the acquisition of advantageous mutations occurring in different individuals and the elimination of deleterious mutations. But the evolution of sexual reproduction remains unclear, because we have limited examples that demonstrate the relative success of sexual lineages in the face of competition from asexual lineages in the same environment. Here we investigated a sympatric occurrence of sexual and asexual reproduction in the pineapple mealybug, Dysmicoccus brevipes. This pest invaded southwestern Japan, including Okinawa and Ishigaki Islands, in the 1930s in association with imported pineapple plants. Our recent censuses demonstrated that on Okinawa sexually reproducing individuals can coexist with and even dominate asexual individuals in the presence of habitat and resource competition, which is considered to be severe for this nearly immobile insect. Molecular phylogeny based on partial DNA sequences in the mitochondrial and nuclear genomes, as well as the endosymbiotic bacterial genome, revealed that the asexual lineage diverged from a common sexual ancestor in the relatively recent past. In contrast, only the asexual lineage exhibiting obligate apomictic thelytoky was discovered on Ishigaki. Co-existence of the two lineages cannot be explained by the results of laboratory experiments, which showed that the intrinsic rate of increase in the sexual lineage was not obviously superior to that of the asexual lineage. Differences in biotic and/or abiotic selective forces operating on the two islands might be the cause of this discrepancy. This biological system offers a unique opportunity to assess

  15. [Relative abundance, population structure, habitat preferences and activity patterns of Tapirus bairdii (Perissodactyla: Tapiridae), in Chimalapas forest, Oaxaca, Mexico].

    Science.gov (United States)

    Lira-Torres, Iván; Briones-Salas, Miguel; Sánchez-Rojas, Gerardo

    2014-12-01

    Baird's tapir (Tapirus bairdii) is endangered primarily because of habitat loss and fragmentation, and overhunting throughout its distribution range. One of the priority land areas for the conservation of this species is the Northern part of its range in the Chimalapas forest, Oaxaca. The aim of this research was to determine the relative abundance, population struc- ture, habitat preferences and activity patterns of Baird's tapir (Tapirus bairdii) in the Chimalapas forest, Oaxaca, Mexico, through the non-invasive technique of camera-trap sampling. A total of five sampling sessions were undertaken among 2009-2013, and used a total of 30 camera-traps in each period. The determinant factor of the sampling design was the hunting between two study areas. A total sampling effort of 9000 trap-days allowed to estimate an index of relative abundance (IRA) of 6.77 tapir photographs/1,000 trap-days (n = 61). IRA varied significantly between sampling stations (Mann-Whitney, p dry season in tropical rain forest without hunting (χ2, p tropical rain forest and secondary vegetation habitats showed higher photo frequency than expected from random (χ2, p forest appears to be the second most important terrestrial priority ecoregion, just after the Mayan Forest (Campeche, Chiapas, Quintana Roo), for the conservation of tapir populations, not only for Mexico but also for Central America.

  16. The distribution, relative abundance, and seasonal phenology of Ceratitis capitata, Ceratitis rosa, and Ceratitis cosyra (Diptera: Tephritidae) in South Africa.

    Science.gov (United States)

    De Villiers, Marelize; Manrakhan, Aruna; Addison, Pia; Hattingh, Vaughan

    2013-10-01

    Ceratitis capitata (Wiedemann), Ceratitis rosa Karsch, and Ceratitis cosyra (Walker) are fruit fly species (Diptera: Tephritidae) of economic importance in South Africa. These pests cause direct damage to a number of commercially produced fruit and are of phytosanitary concern. A study was conducted to determine the distribution, relative abundance, and seasonal occurrence of the three species in different climatic regions of South Africa. The relative abundance and seasonal phenology of C. capitata and C. rosa were also compared between production areas and home gardens in Stellenbosch, Western Cape. Yellow bucket traps baited with Biolure were used to trap the flies over a 2-yr period in the different sampling areas. Different fruit types were sampled in Stellenbosch to determine fruit fly infestation. C. capitata was found to have a widespread distribution in South Africa, whereas C. rosa were absent from or only present in low numbers in the drier regions. C. cosyra was restricted to the North East and East coast, following a similar pattern to the distribution of marula, Sclerocarrya birrea, an important wild host. Fruit in home gardens provided a breeding ground for C. capitata and C. rosa and a source for infestation of orchards when fruit started to mature, highlighting the need for an area-wide strategy for the control of fruit flies.

  17. Can we screen phosphorus movement in the landscape through the analysis of δ"1"8O isotopic abundance in phosphate?

    International Nuclear Information System (INIS)

    Heiling, M.; Aigner, M.; Slaets, J.; Dercon, G.

    2016-01-01

    The SWMCNL explored the possibility of using δ18O isotopic signature in phosphate for screening phosphorus (P) movement in the landscape. Phosphorus is essential for crop production, but extensive use of P fertilizer and animal manure can lead to eutrophication of rivers and lakes. To study these effects, numerous studies on P movement in the soil plant system and P transformation processes have been performed in the past decades. Assessing losses of P through erosion processes, however, is challenging – particularly at the landscape level and on a longer timescale. Using the isotopic signature of stable oxygen isotope ("1"8O) in the phosphate ion as a tracer could be a cost-effective way to study P movements. This approach is already applied as a paleotemperature proxy (the fractionation between phosphate and water is temperature dependent) and can be used for quantifying P losses through leaching into surface and groundwater, as oxygen exchange between phosphate and water is slow in the absence of biological activity.

  18. Carbon isotopes: variations of their natural abundance. Application to correction of radiocarbon dates, to the study of plant metabolism and to paleoclimate

    International Nuclear Information System (INIS)

    Lerman, J.C.

    1974-01-01

    The radiocarbon activity of contemporaneous samples shows: i) variations in the specific activity of the atmospheric C14, which varies with time and locality. ii) variations due to isotope discrimination, or fractionation, of the carbon isotope ratio during the fixation of carbon by organic or inorganic matter. The variation in the atmospheric concentration of carbon 14 as observed in tree rings are synchronous and of the same amplitude for both hemispheres (southern and northern). A curve for correction of radiocarbon dates of the southern hemisphere is given for the last 500 years. The activity of atmospheric radiocarbon as measured in tree rings varies with latitude, showing a difference of (4.5+-1) per mille between the northern and southern hemispheres, the latter having lower concentration of radiocarbon, equivalent to an age difference of about 35 years. This variation can be explained by a larger exchange of carbon 14 between the atmosphere and the sea in the southern hemisphere to a larger free ocean surface (40%) and a higher agitation by winds. The main differences of the isotope fractionation by different types of plants are correlated to their photosynthetic pathways and thus to the enzyme which effects the primary fixation of carbon. The delta C13 values can be used as basis of a paleoclimate indicator [fr

  19. Food resources of stream macroinvertebrates determined by natural-abundance stable C and N isotopes and a 15N tracer addition

    Science.gov (United States)

    Patrick J. Mulholland; Jennifer L. Tank; Diane M. Sanzone; Wilfrid M. Wollheim; Bruce J. Peterson; Jackson R. Webster; Judy L. Meyer

    2000-01-01

    Trophic relationships were examined using natural-abundance 13C and 15N analyses and a 15N-tracer addition experiment in Walker Branch, a 1st-order forested stream in eastern Tennessee. In the 15N-tracer addition experiment, we added 15NH4...

  20. Seasonal and long-term changes in relative abundance of bull sharks from a tourist shark feeding site in Fiji.

    Science.gov (United States)

    Brunnschweiler, Juerg M; Baensch, Harald

    2011-01-27

    Shark tourism has become increasingly popular, but remains controversial because of major concerns originating from the need of tour operators to use bait or chum to reliably attract sharks. We used direct underwater sampling to document changes in bull shark Carcharhinus leucas relative abundance at the Shark Reef Marine Reserve, a shark feeding site in Fiji, and the reproductive cycle of the species in Fijian waters. Between 2003 and 2009, the total number of C. leucas counted on each day ranged from 0 to 40. Whereas the number of C. leucas counted at the feeding site increased over the years, shark numbers decreased over the course of a calendar year with fewest animals counted in November. Externally visible reproductive status information indicates that the species' seasonal departure from the feeding site may be related to reproductive activity.

  1. Associations of hypoosmotic swelling test, relative sperm volume shift, aquaporin7 mRNA abundance and bull fertility estimates.

    Science.gov (United States)

    Kasimanickam, R K; Kasimanickam, V R; Arangasamy, A; Kastelic, J P

    2017-02-01

    Mammalian sperm are exposed to a natural hypoosmotic environment during male-to-female reproductive tract transition; although this activates sperm motility in vivo, excessive swelling can harm sperm structure and function. Aquaporins (AQPs) is a family of membrane-channel proteins implicated in sperm osmoregulation. The objective was to determine associations among relative sperm volume shift, hypoosmotic swelling test (HOST), sperm aquaporin (AQP) 7 mRNA abundances, and sire conception rate (SCR; fertility estimate) in Holstein bulls at a commercial artificial insemination center. Three or four sires for each full point SCR score from -4 to +4 were included. Each SCR estimate for study bulls (N = 30) was based on > 500 services (mean ± SEM) of 725 ± 13 services/sire). Sperm from a single collection day (two ejaculates) from these commercial Holstein bulls were used. Relative mRNA expression of AQP7 in sperm was determined by polymerase chain reaction. Mean relative sperm volume shift and percentage of sperm reacted in a HOST (% HOST) were determined (400 sperm per bull) after incubating in isoosmotic (300 mOsm/kg) and hypoosmotic (100 mOsm/kg) solutions for 30 min. There was no correlation between %HOST and SCR (r = 0.28 P > 0.1). However, there was a positive correlation between relative sperm volume shift and SCR (r = 0.65, P 2) fertility sire groups. In conclusion, bulls with higher SCR had significantly greater AQP7 mRNA abundance in frozen-thawed sperm. This plausibly contributed to greater regulation of sperm volume shift, which apparently conferred protection from detrimental swelling and impaired functions. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Analysis of barium by isotope mass spectrometry

    International Nuclear Information System (INIS)

    Long Kaiming; Jia Baoting; Liu Xuemei

    2004-01-01

    The isotopic abundance ratios for barium at sub-microgram level are analyzed by thermal surface ionization mass spectrometry (TIMS). Rhenium trips used for sample preparation are firstly treated to eliminate possible barium background interference. During the preparation of barium samples phosphoric acid is added as an emitting and stabilizing reagent. The addition of phosphoric acid increases the collection efficiency and ion current strength and stability for barium. A relative standard deviation of 0.02% for the isotopic abundance ratio of 137 Ba to 138 Ba is achieved when the 138 Ba ion current is (1-3) x 10 -12 A. The experimental results also demonstrate that the isotope fractionation effect is negligibly small in the isotopic analysis of barium

  3. Analysis of a herpetofaunal community from an altered marshy area in Sicily; with special remarks on habitat use (niche breadth and overlap), relative abundance of lizards and snakes, and the correlation between predator abundance and tail loss in lizards

    NARCIS (Netherlands)

    Luiselli, L.; Angelici, F.M.; Di Vittorio, M.; Spinnato, A.; Politano, E.

    2005-01-01

    A field survey was conducted in a highly degraded barren environment in Sicily in order to investigate herpetofaunal community composition and structure, habitat use (niche breadth and overlap) and relative abundance of a snake predator and two species of lizard prey. The site was chosen because it

  4. Larval abundance and its relation to macrofouling settlement pattern in the coastal waters of Kalpakkam, southeastern part of India.

    Science.gov (United States)

    Sahu, Gouri; Satpathy, K K; Mohanty, A K; Biswas, Sudeepta; Achary, M Smita; Sarkar, S K

    2013-02-01

    The present work revealed that salinity, water temperature, and food availability were the most crucial factors affecting the abundance of larvae and their settlement as macrofouling community in the coastal waters of Kalpakkam. Quantitative as well as qualitative results showed that late post-monsoon (April-May) and pre-monsoon (June-September) periods were found to be suitable periods for larval growth, development, and survival to adult stages for most of the organisms. Clustering of physico-chemical and biological (including larval and adult availability) data yielded two major clusters; one formed by northeast (NE) monsoon months (October-January) and the other by post-monsoon/summer (February-May) months, whereas; pre-monsoon months (June-September) were distributed between these two clusters. Among all the major macrofouler groups, only bivalves established a successful relationship between its larval abundance and adult settlement. Principal component analysis indicated good associations of bivalve larvae with polychaete larvae and adult bivalves with adult barnacles. However, biotic relation between ascidians and bryozoans was observed both in the larval as well as adult community.

  5. NOAA ESRI Grid - predictions of relative seabird abundance in the New York offshore planning area made by the NOAA Biogeography Branch

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset represents relative seabird abundance predictions from spatial models developed for the New York offshore spatial planning area. This raster was derived...

  6. Isotopic enrichment in a plasma centrifuge

    International Nuclear Information System (INIS)

    Del Bosco, E.; Dallaqua, R.S.; Ludwig, G.O.; Bittencourt, J.A.

    1986-05-01

    A rotating fully ionized plasma column was produced in a vacuum-arc centrifuge. The apparatus is described and new results for the rotational velocity and isotope enrichment of carbon and metal plasmas are shown. The ion rotation velocity is derived from electrostatic probes measurents and from the azimuthal displacement of the material deposited behind of a narrow slit. The isotope enrichment is measured with a modified quadrupole mass spectrometer, which determines, in situ, the relative abundance of the isotopes at the end of the plasm column at various radil positions. (Author) [pt

  7. Role of stable isotope mass spectroscopy in hydrological sciences

    International Nuclear Information System (INIS)

    Keesari, Tirumalesh

    2017-01-01

    Isotope Ratio Mass Spectrometry (IRMS) is a specialized technique used to provide information about a given sample about its geographic, chemical, physical and biological origin. The ability to determine the source of water molecule stems from the relative isotopic abundances of its constituent elements, viz., hydrogen and oxygen or sometimes through its dissolved elements such as carbon, nitrogen and sulphur etc. Since the isotope ratios of carbon, hydrogen, oxygen, sulfur, and nitrogen can become locally enriched or depleted through a variety of kinetic and thermodynamic factors, measurement of the isotope ratios can be used to unravel the processes and differentiate water samples which otherwise exhibit similar chemical signatures. For brevity, this article focuses mainly on measurement of water isotopes, common notation for expressing isotope data and standards, theory of isotope hydrology, field applications and advances

  8. 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)

  9. Ultratrace Uranium Fingerprinting with Isotope Selective Laser Ionization Spectrometry

    International Nuclear Information System (INIS)

    Ziegler, Summer L.; Bushaw, Bruce A.

    2008-01-01

    Uranium isotope ratios can provide source information for tracking uranium contamination in a variety of fields, ranging from occupational bioassay to monitoring aftereffects of nuclear accidents. We describe the development of Isotope Selective Laser Ionization Spectrometry (ISLIS) for ultratrace measurement of the minor isotopes 234U, 235U, and 236U with respect to 238U. Optical isotopic selectivity in three-step excitation with single-mode continuous wave lasers is capable of measuring the minor isotopes at relative abundances below 1 ppm, and is not limited by isobaric interferences such as 235UH+ during measurement of 236U. This relative abundance limit approaches the threshold for measurement of uranium minor isotopes with conventional mass spectrometry, typically 10-7, but without mass spectrometric analysis of the laser-created ions. Uranyl nitrate standards from an international blind comparison were used to test analytical performance for different isotopic compositions and with quantities ranging from 11 ng to 10 (micro)g total uranium. Isotopic ratio determination was demonstrated over a linear dynamic range of 7 orders of magnitude with a few percent relative precision and detection limits below 500 fg for the minor isotopes

  10. The effects of biomanipulation on the biogeochemistry, carbon isotopic composition and pelagic food web relations of a shallow lake

    Directory of Open Access Journals (Sweden)

    B. M. Bontes

    2006-01-01

    Full Text Available In this study we investigated the effects of experimental biomanipulation on community structure, ecosystem metabolism, carbon biogeochemistry and stable isotope composition of a shallow eutrophic lake in the Netherlands. Three different biomanipulation treatments were applied. In two parts of the lake, isolated from the rest, fish was removed and one part was used as a reference treatment in which no biomanipulation was applied. Stable isotopes have proved useful to trace trophic interactions at higher food web levels but until now methodological limitations have restricted species specific isotope analysis in the plankton community. We applied a new approach based on the combination of fluorescence activated cell sorting (FACS and isotope ratio mass spectrometry (IRMS to trace carbon flow through the planktonic food web. With this method we aimed at obtaining group specific δ13C signatures of phytoplankton and to trace possible shifts in δ13C resulting from fish removal. Biomanipulation led to an increase in transparency and macrophyte biomass and decrease in phytoplankton abundance, but zooplankton numbers did not increase. Fish removal also resulted in high pH, high O2, low CO2 and more negative δ13CDIC values than expected, which is attributed to chemical enhanced diffusion with large negative fractionation. Despite high temporal variation we detected differences between the isotopic signatures of the primary producers and between the different treatments. The fractionation values of green algae (~21 and diatoms (~23 were similar and independent of treatment, while fractionation factors of filamentous cyanobacteria were variable between the treatments that differed in CO2 availability. 13C-labeling of the phytoplankton groups showed that biomanipulation led to increased growth rates of green algae and diatoms at the expense of cyanobacteria. Finally, consumers seemed generalists to the available food sources.

  11. Relative Abundance and Diversity of Bacterial Methanotrophs at the Oxic–Anoxic Interface of the Congo Deep-Sea Fan

    Directory of Open Access Journals (Sweden)

    Laurent Toffin

    2017-04-01

    Full Text Available Sitting at ∼5,000 m water depth on the Congo-Angola margin and ∼760 km offshore of the West African coast, the recent lobe complex of the Congo deep-sea fan receives large amounts of fluvial sediments (3–5% organic carbon. This organic-rich sedimentation area harbors habitats with chemosynthetic communities similar to those of cold seeps. In this study, we investigated relative abundance, diversity and distribution of aerobic methane-oxidizing bacteria (MOB communities at the oxic–anoxic interface of sedimentary habitats by using fluorescence in situ hybridization and comparative sequence analysis of particulate mono-oxygenase (pmoA genes. Our findings revealed that sedimentary habitats of the recent lobe complex hosted type I and type II MOB cells and comparisons of pmoA community compositions showed variations among the different organic-rich habitats. Furthermore, the pmoA lineages were taxonomically more diverse compared to methane seep environments and were related to those found at cold seeps. Surprisingly, MOB phylogenetic lineages typical of terrestrial environments were observed at such water depth. In contrast, MOB cells or pmoA sequences were not detected at the previous lobe complex that is disconnected from the Congo River inputs.

  12. K, Rb and Sr abundances and Sr isotopic composition of the Tanzawa granitic and associated gabbroic rocks, Japan: low-potash island arc plutonic complex

    International Nuclear Information System (INIS)

    Ishizaka, K.; Yanagi, T.

    1977-01-01

    The granitic and associated gabbroic rocks of the Tanzawa plutonic complex of Miocene age occurring in the northern part of the Izu-Bonin arc are characterized by low abundances of K (229-6790 ppm) and Rb (0.414-12.1 ppm), low K 2 O/Na 2 O ratios (0.037-0.21), moderately high K/Rb ratios (541-630), low Rb/Sr ratios (0.00137-0.0579) and low initial 87 Sr/ 86 Sr ratios (0.70332-0.70372). This indicates that acid to intermediate plutonic rocks with these geochemical characteristics also occur in island arc environments besides mid-oceanic ridge environments. They represent, together with associated gabbroic rocks, a low-potash island arc plutonic complex and are expected to occur beneath young island arcs, although now unexposed. The Tanzawa plutonic complex may have been formed by differentiation of low-K calc-alkaline magma. (Auth.)

  13. A discussion for the evolution model of Pb isotope of the upper mantle in western Yunnan and its interpretation to the lead isotopic compositions of the regional alkali-rich porphyries and their related rocks

    International Nuclear Information System (INIS)

    Wu Kaixing; Hu Ruizhong; Bi Xianwu; Zhang Qian; Peng Jiantang

    2003-01-01

    Thirty Pb isotope data of the upper mantle in the area of western Yunnan have the similar trends with the Stacey-Kramers' two stage model growth curves but apparently deviate from it on the lead isotope composition programs, which may suggest Pb isotope of the upper mantle in the area of western Yunnan might have two stage evolution history though not fit very well to the Stacey-Kramers' two stage model growth curves. In this paper, a two-stage growth curves which can better fit the Pb isotope data was constructed based on the lead isotope data of the upper mantle in western Yunnan and the principle that Stacey and Kramers constructed the two-stage model and a reasonable interpretation was given to the lead isotopic compositions of the regional alkali-rich porphyries and their related rocks using the model. (authors)

  14. Radiation-related retrograde hydrogen isotope and K-Ar exchange in clay minerals

    International Nuclear Information System (INIS)

    Halter, C.; Pagel, M.; Sheppard, S.M.F.; Weber, F.; Clauer, N.

    1987-01-01

    Hydrogen and oxygen isotope studies have been widely applied to characterize the origin of fluids during ore-foaming processes. The primary isotope record, however, may be disturbed by retrograde exchange reactions, thus complicating the interpretation of the data. The susceptibility of minerals to retrograde isotope and chemical exchange is variable, reflecting differences in the mechanism and rate of isotope exchange. Results are presented on deuterium depletion, K/Ar ages and H 2 O + content of illites associated with uranium mineralization from the Athabasca basin (Canada). (author)

  15. Like will to like: abundances of closely related species can predict susceptibility to intestinal colonization by pathogenic and commensal bacteria.

    Science.gov (United States)

    Stecher, Bärbel; Chaffron, Samuel; Käppeli, Rina; Hapfelmeier, Siegfried; Freedrich, Susanne; Weber, Thomas C; Kirundi, Jorum; Suar, Mrutyunjay; McCoy, Kathy D; von Mering, Christian; Macpherson, Andrew J; Hardt, Wolf-Dietrich

    2010-01-01

    The intestinal ecosystem is formed by a complex, yet highly characteristic microbial community. The parameters defining whether this community permits invasion of a new bacterial species are unclear. In particular, inhibition of enteropathogen infection by the gut microbiota ( = colonization resistance) is poorly understood. To analyze the mechanisms of microbiota-mediated protection from Salmonella enterica induced enterocolitis, we used a mouse infection model and large scale high-throughput pyrosequencing. In contrast to conventional mice (CON), mice with a gut microbiota of low complexity (LCM) were highly susceptible to S. enterica induced colonization and enterocolitis. Colonization resistance was partially restored in LCM-animals by co-housing with conventional mice for 21 days (LCM(con21)). 16S rRNA sequence analysis comparing LCM, LCM(con21) and CON gut microbiota revealed that gut microbiota complexity increased upon conventionalization and correlated with increased resistance to S. enterica infection. Comparative microbiota analysis of mice with varying degrees of colonization resistance allowed us to identify intestinal ecosystem characteristics associated with susceptibility to S. enterica infection. Moreover, this system enabled us to gain further insights into the general principles of gut ecosystem invasion by non-pathogenic, commensal bacteria. Mice harboring high commensal E. coli densities were more susceptible to S. enterica induced gut inflammation. Similarly, mice with high titers of Lactobacilli were more efficiently colonized by a commensal Lactobacillus reuteri(RR) strain after oral inoculation. Upon examination of 16S rRNA sequence data from 9 CON mice we found that closely related phylotypes generally display significantly correlated abundances (co-occurrence), more so than distantly related phylotypes. Thus, in essence, the presence of closely related species can increase the chance of invasion of newly incoming species into the gut

  16. Investigation of the relative abundance of heavy versus light nuclei in primary cosmic rays using underground muon bundles

    International Nuclear Information System (INIS)

    Sundaralingam, N.

    1993-01-01

    We study multiple muon events (muon bundles) recorded underground at a depth of 2090 mwe. To penetrate to this depth, the muons must have energies above 0.8 TeV at the Earth's surface; the primary cosmic ray nuclei which give rise to the observed muon bundles have energies at incidence upon the upper atmosphere of 10 to 10 5 TeV. The events are detected using the Soudan 2 experiment's fine grained tracking calorimeter which is surrounded by a 14 m x10 m x 31 m proportional tube array (the ''active shield''). Muon bundles which have at least one muon traversing the calorimeter, are reconstructed using tracks in the calorimeter together with hit patterns in the proportional tube shield. All ionization pulses are required to be coincident within 3 microseconds. A goal of this study is to investigate the relative nuclear abundances in the primary cosmic radiation around the ''knee'' region (10 3 - 10 4 TeV) of the incident energy spectrum. Four models for the nuclear composition of cosmic rays are considered: The Linsley model, the Constant Mass Composition model (CMC), the Maryland model and the Proton-poor model. A Monte Carlo which incorporates one model at a time is used to simulate events which are then reconstructed using the same computer algorithms that are used for the data. Identical cuts and selections are applied to the data and to the simulated events

  17. Abundances of polycyclic aromatic hydrocarbons (PAHs) in 14 chinese and american coals and their relation to coal rank and weathering

    Science.gov (United States)

    Wang, R.; Liu, Gaisheng; Zhang, Jiahua; Chou, C.-L.; Liu, J.

    2010-01-01

    The abundances of 16 polycyclic aromatic hydrocarbons (PAHs) on the priority list of the United States Environmental Protection Agency (U.S. EPA) have been determined in 14 Chinese and American coals. The ranks of the samples range from lignite, bituminous coal, anthracite, to natural coke. Soxhlet extraction was conducted on each coal for 48 h. The extract was analyzed on a gas chromatograph-mass spectrometer (GC-MS). The results show that the total PAH content ranged from 0.31 to 57.6 ??g/g of coal (on a dry basis). It varied with coal rank and is highest in the maturity range of bituminous coal rank. High-molecular-weight (HMW) PAHs are predominant in low-rank coals, but low-molecular-weight (LMW) PAHs are predominant in high-rank coals. The low-sulfur coals have a higher PAH content than high-sulfur coals. It may be explained by an increasing connection between disulfide bonds and PAHs in high-sulfur coal. In addition, it leads us to conclude that the PAH content of coals may be related to the depositional environment. ?? 2010 American Chemical Society.

  18. Geochemistry of silicon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

    2018-04-01

    Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

  19. Relation between separation factor of carbon isotope and chemical reaction of CO2 with amine in nonaqueous solvent

    International Nuclear Information System (INIS)

    Takeshita, Kenji; Kitamoto, Asashi

    1989-01-01

    The separation factor for carbon isotope exchange reaction between CO 2 and amine in nonaqueous solvent was related to absorption reaction of CO 2 in a solution. The test solutions were mixtures of primary amine (such as butylamine and tert-butylamine) or secondary amine (such as diethylamine, dipropylamine and dibutylamine) diluted with nonpolar solvent (octane or triethyalmine) or polar solvent (methanol), respectively. The isotope exchange reaction consists of three steps related to chemical reaction of CO 2 in amine and nonaqueous solvent mixture, namely the reaction between CO 2 and carbamic acid, that between CO 2 and amine carbamate, and that between CO 2 and carbamic ion. Above all, the isotope separation factor between CO 2 and carbamic acid had the highest value. The overall separation factor can be higher in amine-nonaqueous solvent mixture where the concentration of carbamic acid becomes higher. (author)

  20. Container Type Influences the Relative Abundance, Body Size, and Susceptibility of Ochlerotatus triseriatus (Diptera: Culicidae) to La Crosse Virus.

    Science.gov (United States)

    Bara, Jeffrey J; Muturi, Ephantus J

    2015-05-01

    Ochlerotatus triseriatus (Say), the primary vector of La Crosse virus (LAC), develops in a variety of natural and artificial aquatic containers where it often co-occurs with larvae of other mosquito species. We conducted a field study at two woodlots (South Farms and Trelease Woods) in Urbana, IL, to examine how container type influences vector abundance, body size, and susceptibility to LAC. Mosquito pupae were collected from tree holes, plastic bins, and waste tires, and eclosing adults were identified to species morphologically. Oc. triseriatus and Ochlerotatus japonicus (Theobald) females were orally challenged with LAC and midgut infection rate, disseminated infection rate, and body titer were determined by reverse-transcriptase real-time PCR. Oc. triseriatus was the dominant species collected in tree holes while Oc. japonicus and Culex restuans (Theobald) were mostly dominant in artificial containers. Female Oc. triseriatus and Oc. japonicus collected from plastic bins were significantly larger than those collected from tree holes or waste tires. Oc. japonicus females from South Farms were also significantly larger than those from Trelease Woods. Oc. triseriatus females collected from plastic bins and waste tires were significantly more susceptible to LAC infection relative to females collected from tree holes. In addition, Oc. triseriatus females from waste tires had significantly higher LAC titer relative to Oc. triseriatus from tree holes. For each container type and study site, wing length was not correlated to infection or dissemination rates. These findings suggest that the container type in which Oc.triseriatus develop may contribute to the spatial and temporal dynamics of LAC transmission. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Increase in soil stable carbon isotope ratio relates to loss of organic carbon: results from five long-term bare fallow experiments

    DEFF Research Database (Denmark)

    Menichetti, Lorenzo; Houot, Sabine; van Oort, Folkert

    2015-01-01

    Changes in the 12C/13C ratio (expressed as δ13C) of soil organic C (SOC) has been observed over long time scales and with depth in soil profiles. The changes are ascribed to the different reaction kinetics of 12C and 13C isotopes and the different isotopic composition of various SOC pool components...... examined. The overall estimate of the fractionation coefficient (ε) was −1.2 ± 0.3 ‰. This coefficient represents an important input to studies of long-term SOC dynamics in agricultural soils that are based on variations in 13C natural abundance. The variance of ε may be ascribed to site characteristics...... some impact on isotope abundance and fractionation....

  2. 238U series isotopes and 232Th in carbonates and black shales from the Lesser Himalaya: implications to dissolved uranium abundances in Ganga-Indus source waters

    International Nuclear Information System (INIS)

    Singh, S.K.; Dalai, Tarun K.; Krishnaswami, S.

    2003-01-01

    238 U and 232 Th concentrations and the extent of 238 U- 234 U- 230 Th radioactive equilibrium have been measured in a suite of Precambrian carbonates and black shales from the Lesser Himalaya. These measurements were made to determine their abundances in these deposits, their contributions to dissolved uranium budget of the headwaters of the Ganga and the Indus in the Himalaya and to assess the impact of weathering on 238 U- 234 U- 230 Th radioactive equilibrium in them. 238 U concentrations in Precambrian carbonates range from 0.06 to 2.07 μg g -1 . The 'mean' U/Ca in these carbonates is 2.9 ng U mg -1 Ca. This ratio, coupled with the assumption that all Ca in the Ganga-Indus headwaters is of carbonate origin and that U and Ca behave conservatively in rivers after their release from carbonates, provides an upper limit on the U contribution from these carbonates, to be a few percent of dissolved uranium in rivers. There are, however, a few streams with low uranium concentrations, for which the carbonate contribution could be much higher. These results suggest that Precambrian carbonates make only minor contributions to the uranium budget of the Ganga-Indus headwaters in the Himalaya on a basin wide scale, however, they could be important for particular streams. Similar estimates of silicate contribution to uranium budget of these rivers using U/Na in silicates and Na* (Na corrected for cyclic and halite contributions) in river waters show that silicates can contribute significantly (∼40% on average) to their U balance. If, however, much of the uranium in these silicates is associated with weathering resistant minerals, then the estimated silicate uranium component would be upper limits. Uranium concentration in black shales averages about 37 μg g -1 . Based on this concentration, supply of U from at least ∼50 mg of black shales per liter of river water is needed to balance the average river water U concentration, 1.7 μg L -1 in the Ganga-Indus headwaters

  3. Profiling and relative quantification of phosphatidylethanolamine based on acetone stable isotope derivatization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiang [Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture (China); Hubei Key Laboratory of Lipid Chemistry and Nutrition (China); Wei, Fang, E-mail: willasa@163.com [Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture (China); Hubei Key Laboratory of Lipid Chemistry and Nutrition (China); Xu, Ji-qu; Lv, Xin; Dong, Xu-yan [Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture (China); Hubei Key Laboratory of Lipid Chemistry and Nutrition (China); Han, Xianlin [Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32827 (United States); College of Basic Medical Sciences, Zhejiang Chinese Medical University, 548 Bingwen Road, Hangzhou, Zhejiang 310053 (China); Quek, Siew-young [School of Chemical Science, The University of Auckland, Auckland 1142 (New Zealand); Huang, Feng-hong [Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture (China); Hubei Key Laboratory of Lipid Chemistry and Nutrition (China); Chen, Hong, E-mail: chenhong@oilcrops.cn [Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture (China); Hubei Key Laboratory of Lipid Chemistry and Nutrition (China)

    2016-01-01

    Phosphatidylethanolamine (PE) is considered to be one of the pivotal lipids for normal cellular function as well as disease initiation and progression. In this study, a simple, efficient, reliable, and inexpensive method for the qualitative analysis and relative quantification of PE, based on acetone stable isotope derivatization combined with double neutral loss scan-shotgun electrospray ionization tandem-quadrupole mass spectrometry analysis (ASID-DNLS-Shotgun ESI-MS/MS), was developed. The ASID method led to alkylation of the primary amino groups of PE with an isopropyl moiety. The use of acetone (d{sub 0}-acetone) and deuterium-labeled acetone (d{sub 6}-acetone) introduced a 6 Da mass shift that was ideally suited for relative quantitative analysis, and enhanced sensitivity for mass analysis. The DNLS model was introduced to simultaneously analyze the differential derivatized PEs by shotgun ESI-MS/MS with high selectivity and accuracy. The reaction specificity, labeling efficiency, and linearity of the ASID method were thoroughly evaluated in this study. Its excellent applicability was validated by qualitative and relative quantitative analysis of PE species presented in liver samples from rats fed different diets. Using the ASID-DNLS-Shotgun ESI-MS/MS method, 45 PE species from rat livers have been identified and quantified in an efficient manner. The level of total PEs tended to decrease in the livers of rats on high fat diets compared with controls. The levels of PE 32:1, 34:3, 34:2, 36:3, 36:2, 42:10, plasmalogen PE 36:1 and lyso PE 22:6 were significantly reduced, while levels of PE 36:1 and lyso PE 16:0 increased. - Highlights: • A novel isotope reagent acetone was explored for the derivatization of PEs. • The labeling reaction was carried out under mild conditions with high specificity. • Enhanced detection sensitivity of PEs was achieved after derivatization. • The ASID-DNLS-Shotgun MS/MS method was used to relative quantification of PEs.

  4. Special features of the isotope ratio determination using mass-spectrometer with induction-bound plasma

    International Nuclear Information System (INIS)

    Stepanov, A.I.; Ramendik, G.I.; Fatyushina, E.V.

    2000-01-01

    The origin of the errors arising upon measuring relative abundance of Nd, Yb, and Gd isotopes on a HP-4500 mass-spectrometer (USA) is studied. It is shown that the main origin of the error is the different sensitivity of the mass-spectrometer to ions of different masses. Optimal content of the elements in the solutions is established upon determination of their isotopic abundance [ru

  5. Isotopic separation

    International Nuclear Information System (INIS)

    Castle, P.M.

    1979-01-01

    This invention relates to molecular and atomic isotope separation and is particularly applicable to the separation of 235 U from other uranium isotopes including 238 U. In the method described a desired isotope is separated mechanically from an atomic or molecular beam formed from an isotope mixture utilising the isotropic recoil momenta resulting from selective excitation of the desired isotope species by radiation, followed by ionization or dissociation by radiation or electron attachment. By forming a matrix of UF 6 molecules in HBr molecules so as to collapse the V 3 vibrational mode of the UF 6 molecule the 235 UF 6 molecules are selectively excited to promote reduction of UF 6 molecules containing 235 U and facilitate separation. (UK)

  6. Stable isotope deltas: Tiny, yet robust signatures in nature

    Science.gov (United States)

    Brand, Willi A.; Coplen, Tyler B.

    2012-01-01

    Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and paleoclimatology to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including 14C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. 13C, 2H, and 18O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as−25 per mil can be written as−25 mUr (or−2.5 cUr or−0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg ‘units’ are easily included (e.g. either+0.015 ‰ or+15 per meg

  7. Evaluation of selected ex-reactor accidents related to the tritium and medical isotope production mission at the FFTF

    Energy Technology Data Exchange (ETDEWEB)

    Himes, D.A.

    1997-11-17

    The Fast Flux Test Facility (FFTF) has been proposed as a production facility for tritium and medical isotopes. A range of postulated accidents related to ex-reactor irradiated fuel and target handling were identified and evaluated using new source terms for the higher fuel enrichment and for the tritium and medical isotope targets. In addition, two in-containment sodium spill accidents were re-evaluated to estimate effects of increased fuel enrichment and the presence of the Rapid Retrieval System. Radiological and toxicological consequences of the analyzed accidents were found to be well within applicable risk guidelines.

  8. Chemical and isotopic evolution of a layered eastern U.S. snowpack and its relation to stream-water composition

    Science.gov (United States)

    Shanley, J.B.; Kendall, C.; Albert, M.R.; Hardy, J.P.

    1995-01-01

    The chemical, isotopic, and morphologic evolution of a layered snowpack was investigated during the winter of 1993-94 at Sleepers River Research Watershed in Danville, Vermont. The snowpack was monitored at two small basins: a forested basin at 525 m elevation, and an agricultural basin at 292 m elevation. At each site, the snowpack morphology was characterized and individual layers were sampled seven times during the season. Nitrate and 8d18O profiles in the snowpack remained relatively stable until peak accumulation in mid-March, except near the snow surface, where rain-on-snow events caused water and nitrate movement down to impeding ice layers. Subsequently, water and nitrate moved more readily through the ripening snowpack. As the snowpack evolved, combined processes of preferential ion elution, isotopic fractionation, and infiltration of isotopically heavy rainfall caused the pack to become depleted in solutes and isotopically enriched. The release of nitrate and isotopically depleted water was reflected in patterns of nitrate concentrations and ??18O of meltwater and stream water. Results supported data from the previous year which suggested that streamflow in the forested basin during snowmelt was dominated by groundwater discharge.

  9. Study, using stable isotopes, of flow distribution, surface-groundwater relations and evapotranspiration in the Okavango Swamp, Botswana

    International Nuclear Information System (INIS)

    Dincer, T.; Hutton, L.G.; Kupee, B.B.J.

    1979-01-01

    Stable isotope data collected in the Okavango Delta have confirmed that the central distributary system is more active at present than the peripheral systems. The data also show that there is no groundwater outflow at the western and southern margins of the delta. A salinity-isotope model of the deltaic swamp has been developed to study the relation between the salinity and isotopic composition of the swamp waters. An attempt has been made to separate the atmospheric losses from the swamp into its evapotranspiration components. The results indicate that in winter, when high water levels prevail, these losses are almost entirely due to evaporation whilst in summer, when the water levels are low, evaporation and transpiration contribute almost equally to the total atmospheric losses. (author)

  10. Influence of species, size and relative abundance on the outcomes of competitive interactions between brook trout and juvenile coho salmon

    Science.gov (United States)

    Thornton, Emily J; Duda, Jeff; Quinn, Thomas P.

    2016-01-01

    Resource competition between animals is influenced by a number of factors including the species, size and relative abundance of competing individuals. Stream-dwelling animals often experience variably available food resources, and some employ territorial behaviors to increase their access to food. We investigated the factors that affect dominance between resident, non-native brook trout and recolonizing juvenile coho salmon in the Elwha River, WA, USA, to see if brook trout are likely to disrupt coho salmon recolonization via interference competition. During dyadic laboratory feeding trials, we hypothesized that fish size, not species, would determine which individuals consumed the most food items, and that species would have no effect. We found that species, not size, played a significant role in dominance; coho salmon won 95% of trials, even when only 52% the length of their brook trout competitors. As the pairs of competing fish spent more time together during a trial sequence, coho salmon began to consume more food, and brook trout began to lose more, suggesting that the results of early trials influenced fish performance later. In group trials, we hypothesized that group composition and species would not influence fish foraging success. In single species groups, coho salmon consumed more than brook trout, but the ranges overlapped. Brook trout consumption remained constant through all treatments, but coho salmon consumed more food in treatments with fewer coho salmon, suggesting that coho salmon experienced more intra- than inter-specific competition and that brook trout do not pose a substantial challenge. Based on our results, we think it is unlikely that competition from brook trout will disrupt Elwha River recolonization by coho salmon.

  11. Lowland tapir (Tapirus terrestris) distribution, activity patterns and relative abundance in the Greater Madidi-Tambopata Landscape.

    Science.gov (United States)

    Wallace, Robert; Ayala, Guido; Viscarra, Maria

    2012-12-01

    Lowland tapir distribution is described in northwestern Bolivia and southeastern Peru within the Greater Madidi-Tambopata Landscape, a priority Tapir Conservation Unit, using 1255 distribution points derived from camera trapping efforts, field research and interviews with park guards from 5 national protected areas and hunters from 19 local communities. A total of 392 independent camera trapping events from 14 camera trap surveys at 11 sites demonstrated the nocturnal and crepuscular activity patterns (86%) of the lowland tapir and provide 3 indices of relative abundance for spatial and temporal comparison. Capture rates for lowland tapirs were not significantly different between camera trapping stations placed on river beaches versus those placed in the forest. Lowland tapir capture rates were significantly higher in the national protected areas of the region versus indigenous territories and unprotected portions of the landscape. Capture rates through time suggested that lowland tapir populations are recovering within the Tuichi Valley, an area currently dedicated towards ecotourism activities, following the creation (1995) and subsequent implementation (1997) of the Madidi National Park in Bolivia. Based on our distributional data and published conservative estimates of population density, we calculated that this transboundary landscape holds an overall lowland tapir population of between 14 540 and 36 351 individuals, of which at least 24.3% are under protection from national and municipal parks. As such, the Greater Madidi-Tambopata Landscape should be considered a lowland tapir population stronghold and priority conservation efforts are discussed in order to maintain this population. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

  12. Determination of the decay constants and relative abundances of delayed neutrons by noise analysis in zero-power reactors

    International Nuclear Information System (INIS)

    Diniz, Ricardo

    2005-01-01

    A reactor noise approach has been employed at the IPEN/MB-01 research reactor facility in order to determine experimentally the effective delayed neutron parameters β i and λ i in a six group model and assuming the point reactor. The method can be considered a novice one because exploits the very low frequency domain of the spectral densities. The proposed method has some advantages to other in-pile methods since it does not disturb the reactor system and consequently does not 'excite' any sort of harmonic modes. As a byproduct and a consistency check, the β eff parameter was obtained without the need of the Diven factor and the power normalization and it is in excellent agreement with independent measurements. The theory/experiment comparison shows that for the abundances the JENDL 3.3 presents the best performance while for the decay constants the revised version of ENDF/B-VI.8 shows the best agreement. The best performance for the β eff determination is obtained with JENDL3.3. In contrast, ENDF/B-VI.8 and its revised version performed at LANL overestimate β eff by as much as 4%. The β eff results of this work support totally the proposal of reducing the thermal delayed neutron number for 235 U fission as made by Sakurai and Okajima. A new observed effect related to the correlation between the fluctuations of both measurement channels is also presented and discussed. This effect can be considered as an indirect evidence for the use of the point reactor model in this work as well as a possible useful tool in the understanding of reactor dynamics. (author)

  13. ON THE RELATIVE ABUNDANCE OF LiH AND LiH+ MOLECULES IN THE EARLY UNIVERSE: NEW RESULTS FROM QUANTUM REACTIONS

    International Nuclear Information System (INIS)

    Bovino, Stefano; Tacconi, Mario; Gianturco, Franco A.; Galli, Daniele; Palla, Francesco

    2011-01-01

    The relative efficiencies of the chemical pathways that can lead to the destruction of LiH and LiH + molecules, conjectured to be present in the primordial gas and to control molecular cooling processes in the gravitational collapse of the post-recombination era, are revisited by using accurate quantum calculations for the several reactions involved. The new rates are employed to survey the behavior of the relative abundance of these molecules at redshifts of interest for early universe conditions. We find significant differences with respect to previous calculations, the present ones yielding LiH abundances higher than LiH + at all redshifts.

  14. (32)S/(33)S abundance as a function of galactocentric radius in the Milky Way

    International Nuclear Information System (INIS)

    Greenhouse, M.A.; Thronson, H.A. Jr.

    1986-01-01

    Astration of heavy elements by the stars of the Milky Way forms a fossil record which may preserve spacial distribution of the mass function for the stars in the galaxy. Sulfur is among the last common element for which the relative abundance of its various isotopes have yet to be completely measured within our galaxy. Explosive oxygen burning in massive stars is thought to be the process which dominates sulfur production within stars. There models predict that the various isotopes (S-32, S-33, S-34) are formed in relative abundance which depend strongly upon the mass of the parent star. This relative abundance is thought to be unaffected by subsequent stellar procesing since all important sinks of sulfur destroy it without regard for isotopic form. Hence the spacial variation of the mass function (MF) can be studied by measuring the abundance variation of sulfur isotopes in the galaxy provided that the product yields for these isotopes are known accurately as a function of stellar mass

  15. Nuclear isotope measurement in the Hanford environment

    International Nuclear Information System (INIS)

    Wacker, J.F.; Stoffel, J.J.; Kelley, J.M.

    1995-01-01

    The Pacific Northwest Laboratory (PNL) is located at the federal government's Hanford Site in southeastern Washington State, which was built during World War II as part of the secret Manhattan Project to develop the atomic bomb. Monitoring of the Site itself and surrounding environs for Hanford-related radionuclides has been a routine part of the operations since 1944. One of the most sensitive analytical methods used is thermal ionization mass spectrometry (TIMS) with triple-sector mass spectrometers. Normal geometry instruments have an abundance sensitivity of 10 -9 for uranium while the authors' newest Triple-Sector Isotope Mass Spectrometer (TRISM), utilizing a new ion-optical design developed at PNL, has an abundance sensitivity of 10 -11 . In favorable cases, sensitivity is such that complete isotopic analyses are obtained on total samples in the femtogram range; and minor isotopes in the attogram range are measured

  16. Isotopic analysis of bullet lead samples

    International Nuclear Information System (INIS)

    Sankar Das, M.; Venkatasubramanian, V.S.; Sreenivas, K.

    1976-01-01

    The possibility of using the isotopic composition of lead for the identification of bullet lead is investigated. Lead from several spent bullets were converted to lead sulphide and analysed for the isotopic abundances using an MS-7 mass spectrometer. The abundances are measured relative to that for Pb 204 was too small to permit differentiation, while the range of variation of Pb 206 and Pb 207 and the better precision in their analyses permitted differentiating samples from one another. The correlation among the samples examined has been pointed out. The method is complementary to characterisation of bullet leads by the trace element composition. The possibility of using isotopically enriched lead for tagging bullet lead is pointed out. (author)

  17. Application of General Circulation Models to Assess the Potential Impact of Climate Change on Potential Distribution and Relative Abundance of Melanoplus sanguinipes (Fabricius (Orthoptera: Acrididae in North America

    Directory of Open Access Journals (Sweden)

    O. Olfert

    2011-01-01

    Full Text Available Climate is the dominant factor determining the distribution and abundance of most insect species. In recent years, the issue of climatic changes caused by human activities and the effects on agriculture has raised concern. General circulation model scenarios were applied to a bioclimatic model of Melanoplus sanguinipes to assess the potential impact of global warming on its distribution and relative abundance. Native to North America and widely distributed, M. sanguinipes is one of the grasshopper species of the continent most responsible for economic damage to grain, oilseed, pulse, and forage crops. Compared to predicted range and distribution under current climate conditions, model results indicated that M. sanguinipes would have increased range and relative abundance under the three general circulation model scenarios in more northern regions of North America. Conversely, model output predicted that the range of this crop pest could contract in regions where climate conditions became limiting.

  18. Relative abundance of total subgingival plaque-specific bacteria in salivary microbiota reflects the overall periodontal condition in patients with periodontitis.

    Science.gov (United States)

    Kageyama, Shinya; Takeshita, Toru; Asakawa, Mikari; Shibata, Yukie; Takeuchi, Kenji; Yamanaka, Wataru; Yamashita, Yoshihisa

    2017-01-01

    Increasing attention is being focused on evaluating the salivary microbiota as a promising method for monitoring oral health; however, its bacterial composition greatly differs from that of dental plaque microbiota, which is a dominant etiologic factor of oral diseases. This study evaluated the relative abundance of subgingival plaque-specific bacteria in the salivary microbiota and examined a relationship between the abundance and severity of periodontal condition in patients with periodontitis. Four samples (subgingival and supragingival plaques, saliva, and tongue coating) per each subject were collected from 14 patients with a broad range of severity of periodontitis before periodontal therapy. The bacterial composition was analyzed by 16S rRNA gene amplicon sequencing using Ion PGM. Of the 66 species-level operational taxonomic units (OTUs) representing the mean relative abundance of ≥ 1% in any of the four niches, 12 OTUs corresponding to known periodontal pathogens, including Porphyromonas gingivalis, were characteristically predominant in the subgingival plaque and constituted 37.3 ± 22.9% of the microbiota. The total relative abundance of these OTUs occupied only 1.6 ± 1.2% of the salivary microbiota, but significantly correlated with the percentage of diseased sites (periodontal pocket depth ≥ 4 mm; r = 0.78, P periodontal therapy, the total relative abundance of these 12 OTUs was evaluated as well as before periodontal therapy and reductions of the abundance through periodontal therapy were strongly correlated in saliva and subgingival plaque (r = 0.81, P bacteria representing the present condition of periodontal health.

  19. Relations between fish abundances, summer temperatures, and forest harvest in a northern Minnesota stream system from 1997 to 2007

    Science.gov (United States)

    Eric Merten; Nathaniel Hemstad; Susan Eggert; Lucinda Johnson; Randall Kolka; Bruce Vondracek; Raymond. Newman

    2010-01-01

    Short-term effects of forest harvest on fish habitat have been well documented, including sediment inputs, leaf litter reductions, and stream warming. However, few studies have considered changes in local climate when examining postlogging changes in fish communities. To address this need, we examined fish abundances between 1997 and 2007 in a basin in a northern...

  20. Rock-colonizing plants: abundance of the endemic cactus Mammillaria fraileana related to rock type in the southern Sonoran Desert

    Science.gov (United States)

    Blanca R. Lopez; Yoav Bashan; Macario Bacilio; Gustavo. De la Cruz-Aguero

    2009-01-01

    Establishment, colonization, and permanence of plants affect biogenic and physical processes leading to development of soil. Rockiness, temperature, and humidity are accepted explanations to the influence and the presence of rock-dwelling plants, but the relationship between mineral and chemical composition of rocks with plant abundance is unknown in some regions. This...

  1. Isotopic dynamics of C, O and U in soils and their relation to climate

    OpenAIRE

    Oerter, Erik

    2015-01-01

    The development of soil is driven by environmental conditions, and soil properties are reflective of those conditions. Pedogenic carbonate is widespread in arid and semi-arid soils and its stable C and O isotope composition is often used as a paleoclimate indicator. However, questions remain about the precise meaning of those signals, and most importantly the season(s) that the isotopic composition most closely reflects. Chapter 1 examines the soil conditions that lead to carbonate formation...

  2. Studies of osteoporosis in the Northern China, using isotope-related techniques

    International Nuclear Information System (INIS)

    Qin Linlin; Duan Yunbo; Ma Haibo; Zhang Wei; Ge Chonghua; Liu Zhonghou; Wang Shilin

    1996-01-01

    Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. Osteoporosis is an enormous public health problem, because it causes multiple fractures in the elderly people, and huge health care cost. The progressive aging of the world's population predicts a substantial increase in the global burden of osteoporosis, so further studying and preventing osteoporosis are often important problems. Since 1986 our department started large investigation of BMDat forearm using single photon absorptiometry (SPA) and in 1991-1993 was undertook Investigation of bone mineral density at the lumbar spine and proximal femur in normal Chinese population using Dual Energy X-ray Absorptiometry(DEXA). The results showed the BMD of all above sites is age-related, the age of peak BMD is different at the forearm, lumbar spine and hip, and the difference is related with sex. After the age of peak bone mass, BMD steadily declined with advancing age. In the Co-ordinated Research Programme on Comparative International Studies of Osteoporosis using Isotope Techniques. The first, we will further study age-, sex-related changes in bone mass among Chinese northern healthy residents in urban. Not only consider that chronic disease and medicine influence on osteoporosis, also consider the influence of life-style factors. The second, the trace elements of tooth and hair samples will be analysed by neutron activation analysis (NAA). It try to find the correlation of trace elements composition between tooth and hair samples. The possible difference in theses elements between osteoporotic patients and controls. (author)

  3. Profiling and relative quantification of phosphatidylethanolamine based on acetone stable isotope derivatization.

    Science.gov (United States)

    Wang, Xiang; Wei, Fang; Xu, Ji-Qu; Lv, Xin; Dong, Xu-Yan; Han, Xianlin; Quek, Siew-Young; Huang, Feng-Hong; Chen, Hong

    2016-01-01

    Phosphatidylethanolamine (PE) is considered to be one of the pivotal lipids for normal cellular function as well as disease initiation and progression. In this study, a simple, efficient, reliable, and inexpensive method for the qualitative analysis and relative quantification of PE, based on acetone stable isotope derivatization combined with double neutral loss scan-shotgun electrospray ionization tandem-quadrupole mass spectrometry analysis (ASID-DNLS-Shotgun ESI-MS/MS), was developed. The ASID method led to alkylation of the primary amino groups of PE with an isopropyl moiety. The use of acetone (d0-acetone) and deuterium-labeled acetone (d6-acetone) introduced a 6 Da mass shift that was ideally suited for relative quantitative analysis, and enhanced sensitivity for mass analysis. The DNLS model was introduced to simultaneously analyze the differential derivatized PEs by shotgun ESI-MS/MS with high selectivity and accuracy. The reaction specificity, labeling efficiency, and linearity of the ASID method were thoroughly evaluated in this study. Its excellent applicability was validated by qualitative and relative quantitative analysis of PE species presented in liver samples from rats fed different diets. Using the ASID-DNLS-Shotgun ESI-MS/MS method, 45 PE species from rat livers have been identified and quantified in an efficient manner. The level of total PEs tended to decrease in the livers of rats on high fat diets compared with controls. The levels of PE 32:1, 34:3, 34:2, 36:3, 36:2, 42:10, plasmalogen PE 36:1 and lyso PE 22:6 were significantly reduced, while levels of PE 36:1 and lyso PE 16:0 increased. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Oxygen isotope variability in snow from western Dronning Maud Land, Antarctica and its relation to temperature

    International Nuclear Information System (INIS)

    Helsen, M.M.; Wal, R.S.W. van de; Broeke, M.R. van den; As, D. van; Reijmer, C.H.; Meijer, H.A.J.

    2005-01-01

    This paper presents (delta) 18 O records from snow pits from four locations in Dronning Maud Land, Antarctica that contain at least four annual cycles. The aim of the study was to analyse in detail these records as well as the prevailing temperatures during accumulation in order to infer to what extent isotopic composition in this area can be interpreted as temperature information. The original seasonal amplitudes of the isotope records were reconstructed by use of a simple back-diffusion model. Automatic weather station data were used to describe the accumulation history and the near-surface temperatures; the temperatures at the atmospheric level of snow formation were inferred from a regional climate model. The results show that the strongly intermittent nature of the accumulation in this area can result in the exclusion of entire seasons from the isotope records. The temperature records also reveal that the oxygen isotope records in these snow pits are biased towards higher temperatures, since snowfall conditions are associated with higher temperatures. This effect is greatest at low temperatures. A comparison between the seasonal extreme isotopic and temperature values points out that on timescales of seasons to several years, isotopic variability cannot be interpreted with confidence as temperature changes at the accumulation sites

  5. Isotopic homogeneity of iron in the early solar nebula.

    Science.gov (United States)

    Zhu, X K; Guo, Y; O'Nions, R K; Young, E D; Ash, R D

    2001-07-19

    The chemical and isotopic homogeneity of the early solar nebula, and the processes producing fractionation during its evolution, are central issues of cosmochemistry. Studies of the relative abundance variations of three or more isotopes of an element can in principle determine if the initial reservoir of material was a homogeneous mixture or if it contained several distinct sources of precursor material. For example, widespread anomalies observed in the oxygen isotopes of meteorites have been interpreted as resulting from the mixing of a solid phase that was enriched in 16O with a gas phase in which 16O was depleted, or as an isotopic 'memory' of Galactic evolution. In either case, these anomalies are regarded as strong evidence that the early solar nebula was not initially homogeneous. Here we present measurements of the relative abundances of three iron isotopes in meteoritic and terrestrial samples. We show that significant variations of iron isotopes exist in both terrestrial and extraterrestrial materials. But when plotted in a three-isotope diagram, all of the data for these Solar System materials fall on a single mass-fractionation line, showing that homogenization of iron isotopes occurred in the solar nebula before both planetesimal accretion and chondrule formation.

  6. Distribution of stable isotopes in arid storms . I. Relation between the distribution of isotopic composition in rainfall and in the consequent runoff

    Science.gov (United States)

    Adar, E. M.; Dody, A.; Geyh, M. A.; Yair, A.; Yakirevich, A.; Issar, A. S.

    Temporal distributions of the isotopic composition in arid rain storms and in the associated runoff were investigated in a small arid rocky basin in Israel. Customized rain and runoff samplers provided sequential water samples hermetically sealed in high-density PVC bags. In several storms where the runoff was isotopically depleted, compared with the rainfall, the difference could not be explained by fractionation effects occurring during overland flow. A water-balance study relating the runoff discharge to rainfall over a rocky watershed showed that the entire discharge is produced by a very small segment (1-2mm) of the rain storm. The major objective, therefore, was to provide quantitative relations between segments of rainfall (rain showers and rain spells) and runoff. The time distribution of the composition of stable isotopes (oxygen and hydrogen) was used to quantify the correlation between the rain spell's amount and the consequent runoff. The aim of this work was to (a) utilize the dynamic variations in the isotopic composition in rainfall and runoff and model the magnitude of surface-storage capacity associated with runoff processes of overland flow, and (b) characterize the isotopic composition of the percolating water with respect to the isotopic distribution in rainfall and runoff events. The conceptual model postulates an isotopic mixing of overland flow with water within the depression storage. A transport model was then formulated in order to estimate the physical watershed parameters that control the development of overland flow from a certain rainfall period. Part I (this paper) presents the results and the assessment of the relative depression storage obtained from oxygen-18 and deuterium analyses that lead to the physical and mathematical formulation of a double-component model of kinematic-wave flow and transport, which is presented in Part II (accompanying paper). Résumé Les variations temporelles, en zone aride, de la composition isotopique

  7. The chlorine isotope fingerprint of the lunar magma ocean.

    Science.gov (United States)

    Boyce, Jeremy W; Treiman, Allan H; Guan, Yunbin; Ma, Chi; Eiler, John M; Gross, Juliane; Greenwood, James P; Stolper, Edward M

    2015-09-01

    The Moon contains chlorine that is isotopically unlike that of any other body yet studied in the Solar System, an observation that has been interpreted to support traditional models of the formation of a nominally hydrogen-free ("dry") Moon. We have analyzed abundances and isotopic compositions of Cl and H in lunar mare basalts, and find little evidence that anhydrous lava outgassing was important in generating chlorine isotope anomalies, because (37)Cl/(35)Cl ratios are not related to Cl abundance, H abundance, or D/H ratios in a manner consistent with the lava-outgassing hypothesis. Instead, (37)Cl/(35)Cl correlates positively with Cl abundance in apatite, as well as with whole-rock Th abundances and La/Lu ratios, suggesting that the high (37)Cl/(35)Cl in lunar basalts is inherited from urKREEP, the last dregs of the lunar magma ocean. These new data suggest that the high chlorine isotope ratios of lunar basalts result not from the degassing of their lavas but from degassing of the lunar magma ocean early in the Moon's history. Chlorine isotope variability is therefore an indicator of planetary magma ocean degassing, an important stage in the formation of terrestrial planets.

  8. The relative importance of kinetic mechanisms and variable enzyme abundances for the regulation of hepatic glucose metabolism--insights from mathematical modeling.

    Science.gov (United States)

    Bulik, Sascha; Holzhütter, Hermann-Georg; Berndt, Nikolaus

    2016-03-02

    Adaptation of the cellular metabolism to varying external conditions is brought about by regulated changes in the activity of enzymes and transporters. Hormone-dependent reversible enzyme phosphorylation and concentration changes of reactants and allosteric effectors are the major types of rapid kinetic enzyme regulation, whereas on longer time scales changes in protein abundance may also become operative. Here, we used a comprehensive mathematical model of the hepatic glucose metabolism of rat hepatocytes to decipher the relative importance of different regulatory modes and their mutual interdependencies in the hepatic control of plasma glucose homeostasis. Model simulations reveal significant differences in the capability of liver metabolism to counteract variations of plasma glucose in different physiological settings (starvation, ad libitum nutrient supply, diabetes). Changes in enzyme abundances adjust the metabolic output to the anticipated physiological demand but may turn into a regulatory disadvantage if sudden unexpected changes of the external conditions occur. Allosteric and hormonal control of enzyme activities allow the liver to assume a broad range of metabolic states and may even fully reverse flux changes resulting from changes of enzyme abundances alone. Metabolic control analysis reveals that control of the hepatic glucose metabolism is mainly exerted by enzymes alone, which are differently controlled by alterations in enzyme abundance, reversible phosphorylation, and allosteric effects. In hepatic glucose metabolism, regulation of enzyme activities by changes of reactants, allosteric effects, and reversible phosphorylation is equally important as changes in protein abundance of key regulatory enzymes.

  9. Ferropericlase inclusions in ultradeep diamonds from Sao Luiz (Brazil): high Li abundances and diverse Li-isotope and trace element compositions suggest an origin from a subduction mélange

    Science.gov (United States)

    Seitz, Hans-Michael; Brey, Gerhard P.; Harris, Jeffrey W.; Durali-Müller, Soodabeh; Ludwig, Thomas; Höfer, Heidi E.

    2018-05-01

    The most remarkable feature of the inclusion suite in ultradeep alluvial and kimberlitic diamonds from Sao Luiz (Juina area in Brazil) is the enormous range in Mg# [100xMg/(Mg + Fe)] of the ferropericlases (fper). The Mg-richer ferropericlases are from the boundary to the lower mantle or from the lower mantle itself when they coexist with ringwoodite or Mg- perovskite (bridgmanite). This, however, is not an explanation for the more Fe-rich members and a lowermost mantle or a "D" layer origin has been proposed for them. Such a suggested ultra-deep origin separates the Fe-rich fper-bearing diamonds from the rest of the Sao Luiz ultradeep diamond inclusion suite, which also contains Ca-rich phases. These are now thought to have an origin in the uppermost lower mantle and in the transition zone and to belong either to a peridotitic or mafic (subducted oceanic crust) protolith lithology. We analysed a new set of more Fe-rich ferropericlase inclusions from 10 Sao Luiz ultradeep alluvial diamonds for their Li isotope composition by solution MC-ICP-MS (multi collector inductively coupled plasma mass spectrometry), their major and minor elements by EPMA (electron probe micro-analyser) and their Li-contents by SIMS (secondary ion mass spectrometry), with the aim to understand the origin of the ferropericlase protoliths. Our new data confirm the wide range of ferropericlase Mg# that were reported before and augment the known lack of correlation between major and minor elements. Four pooled ferropericlase inclusions from four diamonds provided sufficient material to determine for the first time their Li isotope composition, which ranges from δ7Li + 9.6 ‰ to -3.9 ‰. This wide Li isotopic range encompasses that of serpentinized ocean floor peridotites including rodingites and ophicarbonates, fresh and altered MORB (mid ocean ridge basalt), seafloor sediments and of eclogites. This large range in Li isotopic composition, up to 5 times higher than `primitive upper mantle' Li-abundances

  10. Long-term temporal and spatial changes in the richness and relative abundance of the inshore fish community of the British North Sea Coast

    Science.gov (United States)

    Henderson, Peter A.

    2017-09-01

    Changes in temporal and spatial composition of the British inshore North Sea fish community are reviewed. Sampling from the cooling water filter screens of power stations bordering the North Sea commenced in the early 1960s. To date, a total of 112 marine fish species have been recorded, a high proportion of the total inshore fish species complement of shallow North Sea British waters. The unrecorded top predators, such as large sharks, swordfish and tuna are not regularly observed in waters fish diversity and abundance in large industrialised estuaries such as the Thames and the Firth of Forth. Linked to spawning and nursery habitat gain, smelt, Osmerus eperlangus, and bass, Dicentrarchus labrax, have greatly increased in abundance. There is no evidence for a decline in species richness since the 1970s. However, elasmobranch species number has declined while two species Raja clavata and Scyliorhinus canicula have remained abundant and one, Mustelus asterias, has increased in abundance. It is argued that overexploitation and habitat destruction remain, as they have been for the last 300 years, the most serious threats to the health of North Sea inshore fish communities. There are no clear signs that climate change is causing species loss, although it may be influencing relative species abundance as species at the southern edge of their range such as the viviparous blenny, Zoarces viviparous, have declined in the southern British North Sea. Power station water temperature records do not show a warming trend, in some estuarine locations temperature has declined with reduced thermal pollution; the temperature record cannot explain the observed major changes in fish relative abundance observed since the 1970s.

  11. Development of empirical relation for isotope of uranium in enriched uranium matrix

    International Nuclear Information System (INIS)

    Srivastava, S.K.; Vidyasagar, D.; Jha, S.K.; Tripathi, R.M.

    2018-01-01

    Uranium enriched in 235 U is required in commercial light water reactors to produce a controlled nuclear reaction. Enrichment allows the 235 U isotopes to be increased from 0.71% to a range between 2% to 5% depending upon requirement. The enriched uranium in the form of sintered UO 2 pellet is used for any commercially operating boiling light water reactors. The enriched uranium fuel bundle surface swipes sample is being analysed to assess the tramp uranium as a quality control parameter. It is known that the 234 U isotope also enriched along with 235 U isotope in conventional gaseous diffusion enrichment process. The information about enrichment percentage of 234 U helps to characterize isotopic properties of enriched uranium. A few reports provide the empirical equation and graphs for finding out the specific activity, activity percentage, activity ratio of 234 U isotopes for enriched uranium. Most of them have not provided the reference for the data used and their source. An attempt has been made to model the relationship between 234 U and 235 U as a function of uranium enrichment at low level

  12. Ca isotopes in refractory inclusions

    International Nuclear Information System (INIS)

    Niederer, F.R.; Papanastassiou, D.A.

    1984-01-01

    We report measurements of the absolute isotope abundance of Ca in Ca-Al-rich inclusions from the Allende and Leoville meteorites. Improved high precision measurements are reported also for 46 Ca. We find that nonlinear isotope effects in Ca are extremely rare in these inclusions. The absence of nonlinear effects in Ca, except for the effects in FUN inclusions, is in sharp contrast to the endemic effects in Ti. One fine-grained inclusion shows an excess of 46 Ca of (7 +- 1) per mille, which is consistent with addition of only 46 Ca or of an exotic (*) component with 46 Ca* approx. 48 Ca*. FUN inclusion EK-1-4-1 shows a small 46 Ca excess of (3.3 +- 1.0) per mille; this confirms that the exotic Ca components in EK-1-4-1 were even more deficient in 46 Ca relative to 48 Ca than is the case for normal Ca. The Ca in the Ca-Al-rich inclusions shows mass dependent isotope fractionation effects which have a range from -3.8 to +6.7 per mille per mass unit difference. This range is a factor of 20 wider than the range previously established for bulk meteorites and for terrestrial and lunar samples. Ca and Mg isotope fractionation effects in the Ca-Al-rich inclusions are common and attributed to kinetic isotope effects. (author)

  13. GALAXIES IN ΛCDM WITH HALO ABUNDANCE MATCHING: LUMINOSITY-VELOCITY RELATION, BARYONIC MASS-VELOCITY RELATION, VELOCITY FUNCTION, AND CLUSTERING

    International Nuclear Information System (INIS)

    Trujillo-Gomez, Sebastian; Klypin, Anatoly; Primack, Joel; Romanowsky, Aaron J.

    2011-01-01

    It has long been regarded as difficult if not impossible for a cosmological model to account simultaneously for the galaxy luminosity, mass, and velocity distributions. We revisit this issue using a modern compilation of observational data along with the best available large-scale cosmological simulation of dark matter (DM). We find that the standard cosmological model, used in conjunction with halo abundance matching (HAM) and simple dynamical corrections, fits—at least on average—all basic statistics of galaxies with circular velocities V circ > 80 km s –1 calculated at a radius of ∼10 kpc. Our primary observational constraint is the luminosity-velocity (LV) relation—which generalizes the Tully-Fisher and Faber-Jackson relations in allowing all types of galaxies to be included, and provides a fundamental benchmark to be reproduced by any theory of galaxy formation. We have compiled data for a variety of galaxies ranging from dwarf irregulars to giant ellipticals. The data present a clear monotonic LV relation from ∼50 km s –1 to ∼500 km s –1 , with a bend below ∼80 km s –1 and a systematic offset between late- and early-type galaxies. For comparison to theory, we employ our new ΛCDM 'Bolshoi' simulation of DM, which has unprecedented mass and force resolution over a large cosmological volume, while using an up-to-date set of cosmological parameters. We use HAM to assign rank-ordered galaxy luminosities to the DM halos, a procedure that automatically fits the empirical luminosity function and provides a predicted LV relation that can be checked against observations. The adiabatic contraction of DM halos in response to the infall of the baryons is included as an optional model ingredient. The resulting predictions for the LV relation are in excellent agreement with the available data on both early-type and late-type galaxies for the luminosity range from M r = –14 to M r = –22. We also compare our predictions for the 'cold' baryon mass (i

  14. Studies of osteoporosis within the Debrecen regional osteoporosis program (drop) in Hungary using isotope related techniques

    International Nuclear Information System (INIS)

    Balogh, A.; Jozsa, Z.; Balogh, Z.; Kiss, A.Z.; Bettembuk, P.

    1996-01-01

    Estimates of the annual incidence of various osteoporotic fractures in Hungary only recently became available. Further prospective data are needed in order to get an estimate on the public health impact of osteoporosis. It has been postulated that beyond genetic factors, environmental effects play important roles in determining the peak bone mass. Many of the influential environmental factors and also the normal course of the development of peak bone mass need further investigation in our region, also to explore suspected interregional differences in bone health. This study will take place in a centre as participant of a multicentre international population study and aims to draw a random sample of the minimum of 105 persons of both sexes from the urban population (15 to 50) of Debrecen, a town of 220 thousand inhabitants in the Eastern region of Hungary and measure bone density of the spine, hip and total body using isotope related techniques. Further goal is to review major lifestyle variables, such as nutrition and exercise. Laboratory markers of bone metabolism will be assayed and bone samples obtained from victims of accidents to analyze bone quality and elemental composition. Alternative bone sites, such as teeth and oral alveolar bone will be also considered sources of bone samples for comparison to other bone regions. The duration of the study will be 4 years and the study subjects will be followed by repeated measurements and clinical assessment. The data will be collected and analyzed according to a common protocol supported by the IAEA. This makes possible comparing data from the participating countries. Experiences of previous work in this Institute on similar subject is also reviewed briefly. (author)

  15. Species composition, diversity and relative abundance of amphibians in forests and non-forest habitats on Langkawi Island, Peninsular Malaysia

    Science.gov (United States)

    Nur Johana, J.; Muzzneena, A. M.; Grismer, L. L.; Norhayati, A.

    2016-11-01

    Anurans on Langkawi Island, Peninsular Malaysia exhibit variation in their habits and forms, ranging from small (SVL 150 mm), and occupy a range of habitats, such as riverine forests, agricultural fields, peat swamps, and lowland and upland dipterocarp forests. These variations provide a platform to explore species diversity, distribution, abundance, microhabitat, and other ecological parameters to understand the distribution patterns and to facilitate conservation and management of sensitive or important species and areas. The objective of this study was to evaluate the diversity and distribution of anuran species in different types of habitat on Langkawi Island. Specimens were collected based on active sampling using the Visual Encounter Survey (VES) method. We surveyed anuran species inhabiting seven types of habitat, namely agriculture (AG), coastal (CL), forest (FT), pond (PD), mangrove (MG), riparian forest (RF) and river (RV). A total of 775 individuals were sampled from all localities, representing 23 species from 12 genera and included all six families of frogs in Malaysia. FT and RF showed high values of Shannon Index, H', 2.60 and 2.38, respectively, followed by the other types of habitat, CL (1.82), RV (1.71), MG (1.56), PD (1.54), and AG (1.53). AG had the highest abundance (156 individuals) compared to other habitat types. Based on Cluster Analysis by using Jaccard coefficient (UPGMA), two groups can be clearly seen and assigned as forested species group (FT and RF) and species associating with human activity (AG, CL, PD, MG and RV). Forest species group is more diverse compared to non-forest group. Nevertheless, non-forest species are found in abundance, highlighting the relevance of these disturbed habitats in supporting the amphibians.

  16. Stable Isotope Group 1983 progress report

    International Nuclear Information System (INIS)

    Stewart, M.K.

    1984-06-01

    The work of the Stable Isotope Group of the Institute of Nuclear Sciences in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and related fields, and mass spectrometer instrumentation, during 1983, is described

  17. 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

  18. Explaining variation in adult Anopheles indoor resting abundance: the relative effects of larval habitat proximity and insecticide-treated bed net use.

    Science.gov (United States)

    McCann, Robert S; Messina, Joseph P; MacFarlane, David W; Bayoh, M Nabie; Gimnig, John E; Giorgi, Emanuele; Walker, Edward D

    2017-07-17

    Spatial determinants of malaria risk within communities are associated with heterogeneity of exposure to vector mosquitoes. The abundance of adult malaria vectors inside people's houses, where most transmission takes place, should be associated with several factors: proximity of houses to larval habitats, structural characteristics of houses, indoor use of vector control tools containing insecticides, and human behavioural and environmental factors in and near houses. While most previous studies have assessed the association of larval habitat proximity in landscapes with relatively low densities of larval habitats, in this study these relationships were analysed in a region of rural, lowland western Kenya with high larval habitat density. 525 houses were sampled for indoor-resting mosquitoes across an 8 by 8 km study area using the pyrethrum spray catch method. A predictive model of larval habitat location in this landscape, previously verified, provided derivations of indices of larval habitat proximity to houses. Using geostatistical regression models, the association of larval habitat proximity, long-lasting insecticidal nets (LLIN) use, house structural characteristics (wall type, roof type), and peridomestic variables (cooking in the house, cattle near the house, number of people sleeping in the house) with mosquito abundance in houses was quantified. Vector abundance was low (mean, 1.1 adult Anopheles per house). Proximity of larval habitats was a strong predictor of Anopheles abundance. Houses without an LLIN had more female Anopheles gambiae s.s., Anopheles arabiensis and Anopheles funestus than houses where some people used an LLIN (rate ratios, 95% CI 0.87, 0.85-0.89; 0.84, 0.82-0.86; 0.38, 0.37-0.40) and houses where everyone used an LLIN (RR, 95% CI 0.49, 0.48-0.50; 0.39, 0.39-0.40; 0.60, 0.58-0.61). Cooking in the house also reduced Anopheles abundance across all species. The number of people sleeping in the house, presence of cattle near the house

  19. Process for separating U isotopes by infrared excitation

    International Nuclear Information System (INIS)

    Lyon, R.K.; Kaldor, Andrew.

    1976-01-01

    This invention concerns a process for separating a substance into at least two parts in which the isotopic abundances of a given element differ from those of the isotopes of the substance prior to separation. Specifically, the invention concerns a process for the selective excitation of the isotopes of a gaseous phase UF 6 by absorption of infra-red photons, then by selective reaction of UF 6 excited with atomics chlorine, bromine or iodine, forming a product that may be separated by a standard method. The preference criteria of the atomic chlorine, bromine and iodine are related to the thermal dilution problem [fr

  20. Optimal sample to tracer ratio for isotope dilution mass spectrometry: the polyisotopic case

    International Nuclear Information System (INIS)

    Laszlo, G.; Ridder, P. de; Goldman, A.; Cappis, J.; Bievre, P. de

    1991-01-01

    The Isotope Dilution Mass Spectrometry (IDMS) measurement technique provides a means for determining the unknown amount of various isotopes of an element in a sample solution of known mass. The sample solution is mixed with an auxiliary solution, or tracer, containing a known amount of the same element having the same isotopes but of different relative abundances or isotopic composition and the induced change in the isotopic composition measured by isotope mass spectrometry. The technique involves the measurement of the abundance ratio of each isotope to a (same) reference isotope in the sample solution, in the tracer solution and in the blend of the sample and tracer solution. These isotope ratio measurements, the known element amount in the tracer and the known mass of sample solution are used to calculate the unknown amount of one isotope in the sample solution. Subsequently the unknown amount of element is determined. The purpose of this paper is to examine the optimization of the ratio of the estimated unknown amount of element in the sample solution to the known amount of element in the tracer solution in order to minimize the relative uncertainty in the determination of the unknown amount of element

  1. Isotopic age relations within the polymetamorphic complex of the island of Naxos (Cyclades, Greece)

    International Nuclear Information System (INIS)

    Andriessen, P.A.M.

    1978-01-01

    A general introduction outlining the goelogical setting, previous work, experimental procedures, analytical errors and constants is given. The results of K-Ar and Rb-Sr isotope dating experiments on the minerals and rocks of different areas are presented. Four phases of metamorphism can be recognised on the island. (C.F.)

  2. Osmium isotope anomalies in chondrites: Results for acid residues and related leachates

    Science.gov (United States)

    Yokoyama, Tetsuya; O'D. Alexander, Conel M.; Walker, Richard J.

    2010-03-01

    We have investigated Os isotope anomalies in acid residues enriched in insoluble organic matter (IOM) extracted from ten primitive chondrites, acid leachates and residues of these fractions, as well as acid leachates of bulk chondrites. Osmium isotopic compositions of bulk carbonaceous, ordinary and enstatite chondrites are also reported. Consistent with prior results, bulk chondrites have homogeneous Os isotope compositions for s-, r-, and p-process nuclides that are indistinguishable from terrestrial, at the current level of resolution. In contrast, nearly all the IOM-rich residues are enriched in s-process Os, evidently due to the preferential incorporation of s-process enriched presolar grains (most likely presolar SiC). Presolar silicate grains that formed in red giant branch (RGB) or asymptotic giant branch (AGB) stars are also likely hosts of additional s-process Os in chondrites. Consistent with one prior study, Os released by weak acid leaching of bulk chondrites is slightly to strongly enriched in r-process nuclides, of which the carrier may be fine-grained presolar silicates formed in supernovae or unidentified solar phases. Collectively, the different, chemically concentrated components in these meteorites are variably enriched in s-, r-, and possibly p-process Os, of which the individual carriers must have been produced in multiple stellar environments. The lack of evidence for Os isotopic heterogeneity among bulk chondrites contrasts with evidence for isotopic heterogeneities for various other elements at approximately the same levels of resolution (e.g., Cr, Mo, Ru, Ba, Sm, and Nd). One possible explanation for this is that the heterogeneities for some elements in bulk materials reflect selective removal of some types of presolar grains as a result of nebular processes, and that because of the strong chemical differences between Os and the other elements, the Os was not significantly affected. Another possible explanation is that late-stage injection

  3. Bacterial 16S rRNA gene analysis revealed that bacteria related to Arcobacter spp. constitute an abundant and common component of the oyster microbiota (Tiostrea chilensis).

    Science.gov (United States)

    Romero, J; García-Varela, M; Laclette, J P; Espejo, R T

    2002-11-01

    To explore the bacterial microbiota in Chilean oyster (Tiostrea chilensis), a molecular approach that permits detection of different bacteria, independently of their capacity to grow in culture media, was used. Bacterial diversity was assessed by analysis of both the 16S rDNA and the 16S-23S intergenic region, obtained by PCR amplifications of DNA extracted from depurated oysters. RFLP of the PCR amplified 16S rDNA showed a prevailing pattern in most of the individuals analyzed, indicating that a few bacterial species were relatively abundant and common in oysters. Cloning and sequencing of the 16S rDNA with the prevailing RFLP pattern indicated that this rRNA was most closely related to Arcobacter spp. However, analysis by the size of the amplified 16S-23S rRNA intergenic regions revealed not Arcobacter spp. but Staphylococcus spp. related bacteria as a major and common component in oyster. These different results may be caused by the absence of target for one of the primers employed for amplification of the intergenic region. Neither of the two bacteria species found in large abundance was recovered after culturing under aerobic, anaerobic, or microaerophilic conditions. This result, however, is expected because the number of bacteria recovered after cultivation was less than 0.01% of the total. All together, these observations suggest that Arcobacter-related strains are probably abundant and common in the Chilean oyster bacterial microbiota.

  4. Origin and abundance of water in carbonaceous asteroids

    Science.gov (United States)

    Marrocchi, Yves; Bekaert, David V.; Piani, Laurette

    2018-01-01

    The origin and abundance of water accreted by carbonaceous asteroids remains underconstrained, but would provide important information on the dynamic of the protoplanetary disk. Here we report the in situ oxygen isotopic compositions of aqueously formed fayalite grains in the Kaba and Mokoia CV chondrites. CV chondrite bulk, matrix and fayalite O-isotopic compositions define the mass-independent continuous trend (δ17O = 0.84 ± 0.03 × δ18O - 4.25 ± 0.1), which shows that the main process controlling the O-isotopic composition of the CV chondrite parent body is related to isotopic exchange between 16O-rich anhydrous silicates and 17O- and 18O-rich fluid. Similar isotopic behaviors observed in CM, CR and CO chondrites demonstrate the ubiquitous nature of O-isotopic exchange as the main physical process in establishing the O-isotopic features of carbonaceous chondrites, regardless of their alteration degree. Based on these results, we developed a new approach to estimate the abundance of water accreted by carbonaceous chondrites (quantified by the water/rock ratio) with CM (0.3-0.4) ≥ CR (0.1-0.4) ≥ CV (0.1-0.2) > CO (0.01-0.10). The low water/rock ratios and the O-isotopic characteristics of secondary minerals in carbonaceous chondrites indicate they (i) formed in the main asteroid belt and (ii) accreted a locally derived (inner Solar System) water formed near the snowline by condensation from the gas phase. Such results imply low influx of D- and 17O- and 18O-rich water ice grains from the outer part of the Solar System. The latter is likely due to the presence of a Jupiter-induced gap in the protoplanetary disk that limited the inward drift of outer Solar System material at the exception of particles with size lower than 150 μm such as presolar grains. Among carbonaceous chondrites, CV chondrites show O-isotopic features suggesting potential contribution of 17-18O-rich water that may be related to their older accretion relative to other hydrated

  5. Distribution, density and abundance of the western Baltic herring ( Clupea harengus ) in the Sound (ICES Subdivision 23) in relation to hydrographical features

    DEFF Research Database (Denmark)

    Nielsen, J. Rasmus; Lundgren, Bo; Jensen, T. F.

    2001-01-01

    Biomass and duration of the over-wintering period of the Rugen spring spawning herring stock (RHS) in the Sound (ICES Subdivison 23) were investigated as well as possible hydrographical factors affecting relative distribution and triggering southwards migration towards the spawning grounds. Monit....... Monitoring was performed during 27 surveys over a 6-year period (1993-1998). Abundance of 45-165 000 t in August-February, 560 000 t in March-May, and...

  6. Relative sea level and coastal environments in arctic Alaska during Marine Isotope Stage 5

    Science.gov (United States)

    Farquharson, L. M.; Mann, D. H.; Jones, B. M.; Rittenour, T. M.; Grosse, G.; Groves, P.

    2015-12-01

    Marine Isotope Stage (MIS) 5 was characterized by marked fluctuations in climate, the warmest being MIS 5e (124-119 ka) when relative sea level (RSL) stood 2-10 m higher than today along many coastlines. In northern Alaska, marine deposits now 5-10 m above modern sea level are assigned to this time period and termed the Pelukian transgression (PT). Complicating this interpretation is the possibility that an intra-Stage 5 ice shelf extended along the Alaskan coast, causing isostatic depression along its grounded margins, which caused RSL highs even during periods of low, global RSL. Here we use optically stimulated luminescence (OSL) to date inferred PT deposits on the Beaufort Sea coastal plain. A transition from what we interpret to be lagoonal mud to sandy tidal flat deposits lying ~ 2.75 m asl dates to 113+/-18 ka. Above this, a 5-m thick gravelly barrier beach dates to 95 +/- 20 ka. This beach contains well-preserved marine molluscs, whale vertebrae, and walrus tusks. Pleistocene-aged ice-rich eolian silt (yedoma) blanket the marine deposits and date to 57.6 +/-10.9 ka. Our interpretation of this chronostratigraphy is that RSL was several meters higher than today during MIS 5e, and lagoons or brackish lakes were prevalent. Gravel barrier beaches moved onshore as local RSL rose further after MIS 5e. The error range of the OSL age of the barrier-beach unit spans the remaining four substages of MIS 5; however, the highstand of RSL on this arctic coastline appears to occurr after the warmest part of the last interglacial and appears not to be coeval with the eustatic maximum reached at lower latitudes during MIS 5. One possibility is that RSL along the Beaufort Sea coast was affected by isostatic depression caused by an ice shelf associated with widespread, intra-Stage 5 glaciation that was out of phase with lower latitude glaciation and whose extent and timing remains enigmatic.

  7. Relative Abundance of Carsonella ruddii (Gamma Proteobacterium) in Females and Males of Cacopsylla pyricola (Hemiptera: Psyllidae) and Bactericera cockerelli (Hemiptera: Triozidae)

    Science.gov (United States)

    Cooper, W. Rodney; Garczynski, Stephen F.; Horton, David R.

    2015-01-01

    Carsonella ruddii (Gamma Proteobacterium) is an obligate bacterial endosymbiont of psyllids that produces essential amino acids that are lacking in the insect’s diet. Accurate estimations of Carsonella populations are important to studies of Carsonella-psyllid interactions and to developing ways to target Carsonella for control of psyllid pests including pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae) and potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). We used two methods, namely fluorescence in situ hybridization and quantitative polymerase chain reaction (qPCR), to estimate relative abundance of Carsonella in bacteriocytes and whole bodies of psyllids, respectively. Using these two methods, we compared Carsonella populations between female and male insects. Estimations using fluorescence in situ hybridization indicated that Carsonella was more abundant in bacteriocytes of female C. pyricola than in those of males, but Carsonella abundance in bacteriocytes did not differ between sexes of B. cockerelli. Analyses by qPCR using whole-body specimens indicated Carsonella was more abundant in females than in males of both psyllids. Neither fluorescence in situ hybridization nor qPCR indicated that Carsonella populations differed in abundance among adults of different ages (0–3 wk after adult eclosion). Using fluorescence in situ hybridization, Carsonella was observed in ovarioles of newly emerged females and formed an aggregation in the posterior end of mature oocytes. Results of our study indicate that female psyllids harbor greater populations of Carsonella than do males and that sex should be controlled for in studies which require estimations of Carsonella populations. PMID:26056318

  8. Application of Stable Isotope Signatures in Food Traceability

    International Nuclear Information System (INIS)

    Nazaratul Ashifa Abdullah Salim; Roslanzairi Mostapha; Zainon Othman; Nor Afiqah Harun; Mohd Suhaimi Hamzah; Shamsiah Abdul Rahman; Md Suhaimi Elias; Salmah Moosa

    2015-01-01

    Stable isotope analysis has widely been used to trace the origin of organic materials in various fields, such as geochemistry, biochemistry, archaeology and petroleum. In past a decade, it has also become an important tool for food traceability study. The globalization of food markets and the relative ease with which food commodities are transported through and between countries and continents, means that consumers are increasingly concerned about the origin of the foods they eat. The natural abundance isotope variation such as carbon, nitrogen, hydrogen and oxygen are use as geographic tracers or marker to determine the geographic origin of fruits, crop, vegetables and food products from animal. The isotopic compositions of plant materials reflect various factors such as isotopic compositions of source materials and their assimilation processes as well as growth environments. This paper will discuss on stable carbon and nitrogen isotopic compositions in rice, advantages, limitations and potential of other analysis applications that can be incorporated in food traceability system. (author)

  9. Lead isotopic characterization of respirable urban aerosols and related sources, Santiago-Chile

    International Nuclear Information System (INIS)

    Diaz, M; Kawashita, K; Antinao, J.L

    2001-01-01

    Santiago de Chile is located in a poorly ventilated valley at 33 o 30' latitude south at an altitude of 550m. Local climate is semi-arid with mean annual rainfall below 350mm. The atmospheric particles constitute one of the main factors of urban air pollution in the city. Morphological characterization of airborne particles of Santiago done by Scanning Electron Microscopy showed the presence of three groups of particles: crystalline. spherical and agglomerate particles. The crystalline shapes originated in geologic sources have perfectly defined crystallographic parameters. The agglomerated shapes are formed by organic material and submicrometrical mineral particles derived from combustion of fossil fuel and the spherical shapes are products of metallurgical activities. Some of them could been associated with the wear of motorcars. Samples of aerosols. sediments and leaded petrol of different distributors were collected. Aerosols were sampled in two sites of Santiago: the Movil monitoring station, at east of the city, and Parque O'Higgins monitoring station in downtown. These two monitoring stations belong to the MACAM network. Sediments of Mapocho, Maipo, San Francisco and Zanjon de la Aguada rivers and two samples from Disputada and Merceditas ores were studied. All the samples have been measured for their 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios. The experimental chemical procedures of sample dissolution and Pb separation by anion exchange chromatography were developed in the Sernageomin clean laboratory of Santiago de Chile. The isotopic measurements were made using a VG-Sector isotope ratio mass spectrometer fitted with a thermal ion source, multi Faraday collector and Daly collector of the Isotopic Geology Laboratory in the Universidade Federal de Rio Grande do Sul, Brazil. The measurements were corrected using NBS 981 and 982 standards. Isotopic results plotted in a 208 Pb/ 204 Pb versus 206 Pb/ 204 Pb diagram and in a 207 Pb/ 204 Pb versus

  10. On the relations between the oceanic uptake of CO2 and its carbon isotopes

    International Nuclear Information System (INIS)

    Heimann, M.; Maier-Reimer, E.

    1994-01-01

    The recent proposals to estimate the oceanic uptake of CO 2 by monitoring the oceanic change in 13 C/ 12 C isotope ratio or the air-sea 13 C/ 12 C isotopic disequilibrium is reviewed. Because the history of atmospheric CO 2 and 13 CO 2 since preindustrial times is almost the same, the oceanic penetration depth of both tracers must be the same. This dynamic constraint permits the establishment of yet a third method to estimate the global ocean uptake of CO 2 from 13 C measurements. Using available observations in conjunction with canonical values for the global carbon cycle parameters the three methods yield inconsistent oceanic CO 2 uptake rates for the time period 1970-1990, ranging from 0 to over 3 GtC year -1 . However, uncertainties in the available carbon cycle data must be taken into account. Using a non-linear estimation procedure, a consistent scenario with an oceanic CO 2 uptake rate of 2.2±0.8 GtC year -1 can be established. The method also permits an investigation of the sensitivities of the different approaches. An analysis of the results of two three-dimensional simulations with the Hamburg Model of the Oceanic Carbon Cycle shows that the 13 C isotope indeed tracks the oceanic penetration of anthropogenic CO 2 . Because of its different time history, bomb produced radiocarbon, as measured at the time of GEOSECS, correlates much less well to excess carbon. (orig.)

  11. Origin of depleted components in basalt related to the Hawaiian hot spot: Evidence from isotopic and incompatible element ratios

    Science.gov (United States)

    Frey, F. A.; Huang, S.; Blichert-Toft, J.; Regelous, M.; Boyet, M.

    2005-02-01

    The radiogenic isotopic ratios of Sr, Nd, Hf, and Pb in basaltic lavas associated with major hot spots, such as Hawaii, document the geochemical heterogeneity of their mantle source. What processes created such heterogeneity? For Hawaiian lavas there has been extensive discussion of geochemically enriched source components, but relatively little attention has been given to the origin of depleted source components, that is, components with the lowest 87Sr/86Sr and highest 143Nd/144Nd and 176Hf/177Hf. The surprisingly important role of a depleted component in the source of the incompatible element-enriched, rejuvenated-stage Hawaiian lavas is well known. A depleted component also contributed significantly to the ˜76-81 Ma lavas erupted at Detroit Seamount in the Emperor Seamount Chain. In both cases, major involvement of MORB-related depleted asthenosphere or lithosphere has been proposed. Detroit Seamount and rejuvenated-stage lavas, however, have important isotopic differences from most Pacific MORB. Specifically, they define trends to relatively unradiogenic Pb isotope ratios, and most Emperor Seamount lavas define a steep trend of 176Hf/177Hf versus 143Nd/144Nd. In addition, lavas from Detroit Seamount and recent rejuvenated-stage lavas have relatively high Ba/Th, a characteristic of lavas associated with the Hawaiian hot spot. It is possible that a depleted component, intrinsic to the hot spot, has contributed to these young and old lavas related to the Hawaiian hot spot. The persistence of such a component over 80 Myr is consistent with a long-lived source, i.e., a plume.

  12. Boron-isotope fractionation in plants

    Energy Technology Data Exchange (ETDEWEB)

    Marentes, E [Univ. of Guelph, Dept. of Horticultural Science, Guelph, Ontario (Canada); Vanderpool, R A [USDA/ARS Grand Forks Human Nutrition Research Center, Grand Forks, North Dakota (United States); Shelp, B J [Univ. of Guelph, Dept. of Horticultural Science, Guelph, Ontario (Canada)

    1997-10-15

    Naturally-occurring variations in the abundance of stable isotopes of carbon, nitrogen, oxygen, and other elements in plants have been reported and are now used to understand various physiological processes in plants. Boron (B) isotopic variation in several plant species have been documented, but no determination as to whether plants fractionate the stable isotopes of boron, {sup 11}B and {sup 10}B, has been made. Here, we report that plants with differing B requirements (wheat, corn and broccoli) fractionated boron. The whole plant was enriched in {sup 11}B relative to the nutrient solution, and the leaves were enriched in {sup 10}B and the stem in {sup 11}B relative to the xylem sap. Although at present, a mechanistic role for boron in plants is uncertain, potential fractionating mechanisms are discussed. (author)

  13. Boron-isotope fractionation in plants

    International Nuclear Information System (INIS)

    Marentes, E.; Vanderpool, R.A.; Shelp, B.J.

    1997-01-01

    Naturally-occurring variations in the abundance of stable isotopes of carbon, nitrogen, oxygen, and other elements in plants have been reported and are now used to understand various physiological processes in plants. Boron (B) isotopic variation in several plant species have been documented, but no determination as to whether plants fractionate the stable isotopes of boron, 11 B and 10 B, has been made. Here, we report that plants with differing B requirements (wheat, corn and broccoli) fractionated boron. The whole plant was enriched in 11 B relative to the nutrient solution, and the leaves were enriched in 10 B and the stem in 11 B relative to the xylem sap. Although at present, a mechanistic role for boron in plants is uncertain, potential fractionating mechanisms are discussed. (author)

  14. The use of kDNA minicircle subclass relative abundance to differentiate between Leishmania (L.) infantum and Leishmania (L.) amazonensis.

    Science.gov (United States)

    Ceccarelli, Marcello; Galluzzi, Luca; Diotallevi, Aurora; Andreoni, Francesca; Fowler, Hailie; Petersen, Christine; Vitale, Fabrizio; Magnani, Mauro

    2017-05-16

    Leishmaniasis is a neglected disease caused by many Leishmania species, belonging to subgenera Leishmania (Leishmania) and Leishmania (Viannia). Several qPCR-based molecular diagnostic approaches have been reported for detection and quantification of Leishmania species. Many of these approaches use the kinetoplast DNA (kDNA) minicircles as the target sequence. These assays had potential cross-species amplification, due to sequence similarity between Leishmania species. Previous works demonstrated discrimination between L. (Leishmania) and L. (Viannia) by SYBR green-based qPCR assays designed on kDNA, followed by melting or high-resolution melt (HRM) analysis. Importantly, these approaches cannot fully distinguish L. (L.) infantum from L. (L.) amazonensis, which can coexist in the same geographical area. DNA from 18 strains/isolates of L. (L.) infantum, L. (L.) amazonensis, L. (V.) braziliensis, L. (V.) panamensis, L. (V.) guyanensis, and 62 clinical samples from L. (L.) infantum-infected dogs were amplified by a previously developed qPCR (qPCR-ML) and subjected to HRM analysis; selected PCR products were sequenced using an ABI PRISM 310 Genetic Analyzer. Based on the obtained sequences, a new SYBR-green qPCR assay (qPCR-ama) intended to amplify a minicircle subclass more abundant in L. (L.) amazonensis was designed. The qPCR-ML followed by HRM analysis did not allow discrimination between L. (L.) amazonensis and L. (L.) infantum in 53.4% of cases. Hence, the novel SYBR green-based qPCR (qPCR-ama) has been tested. This assay achieved a detection limit of 0.1 pg of parasite DNA in samples spiked with host DNA and did not show cross amplification with Trypanosoma cruzi or host DNA. Although the qPCR-ama also amplified L. (L.) infantum strains, the C q values were dramatically increased compared to qPCR-ML. Therefore, the combined analysis of C q values from qPCR-ML and qPCR-ama allowed to distinguish L. (L.) infantum and L. (L.) amazonensis in 100% of tested samples

  15. Isotope hydrology in Latin America

    Energy Technology Data Exchange (ETDEWEB)

    Payne, B R [International Atomic Energy Agency, Division of Research and Laboratories, Isotope Hydrology Section, Vienna (Austria)

    1972-07-01

    A wide variety of problems in hydrology have proved susceptible to the use of nuclear techniques. Conclusions may be drawn from the relative abundances of certain 'environmental isotopes', such as heavy stable isotopes of hydrogen and oxygen in water molecules, tritium, carbon-14 and silicon-32, in atmospheric, surface or ground water; origin and rate of flow, for example, may be deduced. Artificial radioisotopes may be used similarly as a logical extension to well-known tracer techniques using dyes and salts. Inherent in the use of such radiotracers are the advantages of very high detection sensitivity (and thus very low required concentrations and the elimination of density effects), and a choice of a variety of nuclides alien to the geohydrological system (and hence unique identification and low background). (author)

  16. The abundance and pollen foraging behaviour of bumble bees in relation to population size of whortleberry (Vaccinium uliginosum.

    Directory of Open Access Journals (Sweden)

    Carolin Mayer

    Full Text Available Habitat fragmentation can have severe effects on plant pollinator interactions, for example changing the foraging behaviour of pollinators. To date, the impact of plant population size on pollen collection by pollinators has not yet been investigated. From 2008 to 2010, we monitored nine bumble bee species (Bombus campestris, Bombus hortorum s.l., Bombus hypnorum, Bombus lapidarius, Bombus pascuorum, Bombus pratorum, Bombus soroensis, Bombus terrestris s.l., Bombus vestalis s.l. on Vaccinium uliginosum (Ericaceae in up to nine populations in Belgium ranging in size from 80 m(2 to over 3.1 ha. Bumble bee abundance declined with decreasing plant population size, and especially the proportion of individuals of large bumble bee species diminished in smaller populations. The most remarkable and novel observation was that bumble bees seemed to switch foraging behaviour according to population size: while they collected both pollen and nectar in large populations, they largely neglected pollen collection in small populations. This pattern was due to large bumble bee species, which seem thus to be more likely to suffer from pollen shortages in smaller habitat fragments. Comparing pollen loads of bumble bees we found that fidelity to V. uliginosum pollen did not depend on plant population size but rather on the extent shrub cover and/or openness of the site. Bumble bees collected pollen only from three plant species (V.uliginosum, Sorbus aucuparia and Cytisus scoparius. We also did not discover any pollination limitation of V. uliginosum in small populations. We conclude that habitat fragmentation might not immediately threaten the pollination of V. uliginosum, nevertheless, it provides important nectar and pollen resources for bumble bees and declining populations of this plant could have negative effects for its pollinators. The finding that large bumble bee species abandon pollen collection when plant populations become small is of interest when

  17. Offal dumping sites influence the relative abundance and roosting site selection of Black Kites (Milvus migrans govinda) in urban landscape: a study from Kolkata metropolis, India.

    Science.gov (United States)

    Mazumdar, Subhendu; Ghose, Dipankar; Saha, Goutam Kumar

    2017-12-14

    Although Black Kites (Milvus migrans govinda) serve as major scavenging raptor in most of the urban areas, scientific studies on this important ecosystem service provider are almost non-existent in Indian context. The present study was carried out in a metropolis in eastern India to find out the factors influencing relative abundance and roosting site selection of Black Kites. Separate generalized linear models (GLMs) were performed considering encounter rate and roosting Black Kite abundance as response variables. The study conclusively indicated that encounter rates of Black Kites were significantly influenced by the presence of garbage dumps in its vicinity. Numbers of Black Kites were also higher in the roosting sites situated closer to garbage dumps and open spaces. In addition, expected counts of Black Kites significantly increased in roosting sites situated away from buildings and water bodies. However, built-up area and tree cover around the roosting sites had no influence on the abundance of Black Kites therein. With rapid urbanization and changing offal disposal patterns, our findings would be useful to ensure continued availability of food and roosting sites of Black Kites in urban areas.

  18. Collision-Induced Dissociation of Deprotonated Peptides. Relative Abundance of Side-Chain Neutral Losses, Residue-Specific Product Ions, and Comparison with Protonated Peptides.

    Science.gov (United States)

    Liang, Yuxue; Neta, Pedatsur; Yang, Xiaoyu; Stein, Stephen E

    2018-03-01

    High-accuracy MS/MS spectra of deprotonated ions of 390 dipeptides and 137 peptides with three to six residues are studied. Many amino acid residues undergo neutral losses from their side chains. The most abundant is the loss of acetaldehyde from threonine. The abundance of losses from the side chains of other amino acids is estimated relative to that of threonine. While some amino acids lose the whole side chain, others lose only part of it, and some exhibit two or more different losses. Side-chain neutral losses are less abundant in the spectra of protonated peptides, being significant mainly for methionine and arginine. In addition to the neutral losses, many amino acid residues in deprotonated peptides produce specific negative ions after peptide bond cleavage. An expanded list of fragment ions from protonated peptides is also presented and compared with those of deprotonated peptides. Fragment ions are mostly different for these two cases. These lists of fragments are used to annotate peptide mass spectral libraries and to aid in the confirmation of specific amino acids in peptides. Graphical Abstract ᅟ.

  19. Laser assisted aerodynamic isotope separation

    International Nuclear Information System (INIS)

    Berg, H. van den

    1985-01-01

    It is shown that the efficiency of conventional aerodynamic isotope seperation can be improved by two orders of magnitude with the aid of a relatively weak cw infrared laser which is used to induce isotopically selective condensation. Overall isotope enrichment factors in excess of 2 are obtained as compared to about 1.02 in the conventional seperation. Sulphur isotopes in SF 6 as well as Silicon isotopes in SiF 4 and Bromine isotopes in CF 3 Br are seperated on a laboratory scale. Infrared vibrational predissociation by itself and in combination with isotopically selective condensation are also shown to be effective new ways of isotope separation. (orig.) [de

  20. Plant Macrofossils from the Takht Coal Mine, Minoodasht and its Dating, Relative abundance and Sørensen index in comparison with the other Florizones in Iran and Eurasia

    Directory of Open Access Journals (Sweden)

    Fatemeh Vaez Javadi

    2015-02-01

    Full Text Available Takht mine, SE Minoodasht contains well-preserved plant macrofossils belonging to 27 species allocated to 22 genera of various orders viz., Equisetales, Osmundales, Filicales, Peltaspermales, Bennettitales, Ginkgoales and Coniferales. The plant macrofossils in this area are studied for the first time. Based on the occurrence of Equisetites muensteri, Clathropteris meniscoides, Dictyophyllum exile, Anthrophyopsis crassinervis, Scytophyllum persicum, Pterophyllum bavieri, and Baiera muensteriana a Rhaetian age is suggested for this assemblage. Since, there was no differentiation between formations in geological map these flora emphasized spreading the Kalariz Formation in this area. The Minoodasht flora is correlated to the plant macrofossil assemblages of Zirab, Tazareh, Narges-Chal, Hiv, Jajarm (Alborz, Parvadeh mines (Tabas, and Darbid-Khun (Kerman Basin. Therefore, there were close floristic relationships between North and Central-East Iran (i.e. Kerman Basin and Tabas Block and two areas were palaeogeographically closely related, probably forming a uniform paleoenvironment. On the basis of relative abundances of taxa, Filicales, Bennettitales, Ginkgoales and Pinales were 42.02%, 38.11%, 7.17% and 6.51%, respectively. It is noteworthy that variety and relative abundance of the species of Filicophyta and Bennetittales were high within Iran during the Late Triassic epoch. Therefore, a warm wet climatic regime dominated. In addition, a more uniform climate in continental scale is suggested. On the basis of similarity indices and relative abundance of taxa, Iran located within Eurasia climatic belt, Euro-Sinian Region, and the Middle Asia Province of Vakhrameev’s subdivisions and south-western region of Dubroskina’s subdivisions during this epoch.

  1. SFCOMPO 2.0 - A relational database of spent fuel isotopic measurements, reactor operational histories, and design data

    Science.gov (United States)

    Michel-Sendis, Franco; Martinez-González, Jesus; Gauld, Ian

    2017-09-01

    SFCOMPO-2.0 is a database of experimental isotopic concentrations measured in destructive radiochemical analysis of spent nuclear fuel (SNF) samples. The database includes corresponding design description of the fuel rods and assemblies, relevant operating conditions and characteristics of the host reactors necessary for modelling and simulation. Aimed at establishing a thorough, reliable, and publicly available resource for code and data validation of safety-related applications, SFCOMPO-2.0 is developed and maintained by the OECD Nuclear Energy Agency (NEA). The SFCOMPO-2.0 database is a Java application which is downloadable from the NEA website.

  2. Chromatographic determination of the relative retention of isotopic species of oxygen in methanol and methan-d3-ol

    International Nuclear Information System (INIS)

    Pauls, R.E.; Mahle, N.H.; Shepard, A.T.; Gaw, J.C.; Rogers, L.B.

    1976-08-01

    A high-precision gas chromatograph was used in conjunction with a quadrupole mass filter and an on-line computer to study the fractionation of oxygen isotopes by Porapak T and glycerol in CH 3 OH and CD 3 OH as a function of temperature. Values of relative retention on the order of 1.002 compared favorably with results for the vapor pressure ratio obtained by classical means. Differences from unity were much smaller for the activity-coefficient ratio than for the vapor-pressure ratio. Differential thermodynamic data were also reported

  3. SFCOMPO 2.0 – A relational database of spent fuel isotopic measurements, reactor operational histories, and design data

    Directory of Open Access Journals (Sweden)

    Michel-Sendis Franco

    2017-01-01

    Full Text Available SFCOMPO-2.0 is a database of experimental isotopic concentrations measured in destructive radiochemical analysis of spent nuclear fuel (SNF samples. The database includes corresponding design description of the fuel rods and assemblies, relevant operating conditions and characteristics of the host reactors necessary for modelling and simulation. Aimed at establishing a thorough, reliable, and publicly available resource for code and data validation of safety-related applications, SFCOMPO-2.0 is developed and maintained by the OECD Nuclear Energy Agency (NEA. The SFCOMPO-2.0 database is a Java application which is downloadable from the NEA website.

  4. Distribution, relative abundance and occupancy of selected mammals along paved road in Kubah National Park, Sarawak, Borneo

    Directory of Open Access Journals (Sweden)

    Jayasilan Mohd-Azlan

    2018-06-01

    (Tragulus kanchil showed preference at 5–100 m. This might be due to their general diet behaviour and abundance of food resources nearby the forest edge. The findings from this study need to be carefully interpreted as it is based on a small scale project, therefore may not provide information required to quantify and mitigate the negative effects of roads in protected areas. Comprehensive long-term monitoring with appropriate replications, will be required for making appropriate management recommendations for enhancing conservation within the protected areas of Sarawak.

  5. Distribution and Abundance of Human Specific Bacteroides and Relation to Traditional Indicators in an Urban Tropical Catchment

    Science.gov (United States)

    Nshimyimana, J.; Shanahan, P.; Thompson, J. R.; Ekklesia, E.; Chua Hock Chye, L.

    2012-12-01

    The Singapore government through its Public Utilities Board is interested in opening Kranji Reservoir to recreational use. However, water courses within the Kranji Reservoir catchment contain human fecal indicator bacteria above recreational water quality criteria; their sources and distribution are unknown. The primary goals of this study were to determine the distribution of fecal indicator bacteria in drainages and water bodies in the Kranji reservoir catchment area. Total coliforms, E. coli, and the DNA-based HF marker (targeting a human specific strain of Bacteroides) were quantified in 27 samples collected in January 2009 and 54 samples collected in July 2009. Correlation of HF marker cell equivalents (CE) and E. coli abundance (colony forming units (CFU) or Most Probable Number (MPN)) to different land-use categories revealed potential sources of fecal contamination to the Kranji reservoir. Notably, areas designated as farming/agricultural were associated with the highest levels of E. coli (geometric mean 30,500 CFU/100 ml) and HF marker (1.23±1.13x106 CE/100 ml ± S.D.) while in general lower HF marker and E. coli levels were observed in residential areas, undeveloped areas, and within the Kranji reservoir (i.e. Kranji Reservoir had 2 to 17 MPN/100 ml of E. coli and 103 to 105 HF marker CE/100 ml). A partial survey of potential point sources for fecal contamination within the farming area revealed a wastewater effluent stream with HF marker levels exceeding 107 CE/100ml. As observed in previous studies, total coliforms and E. coli levels were weakly (Robligate anaerobe that is not expected to grow in aerated surface waters. In contrast, numerous studies have demonstrated that total coliforms, including E. coli, are able to grow well under some tropical conditions, limiting their utility as neutral tracers of fecal contamination in tropical environments. Phylogenetic analysis of cloned HF marker sequences from Kranji reservoir and catchment samples

  6. Abundance, biting behaviour and parous rate of anopheline mosquito species in relation to malaria incidence in gold-mining areas of southern Venezuela.

    Science.gov (United States)

    Moreno, J E; Rubio-Palis, Y; Páez, E; Pérez, E; Sánchez, V

    2007-12-01

    A longitudinal entomological and epidemiological study was conducted in five localities of southern Venezuela between January 1999 and April 2000 to determine the abundance, biting behaviour and parity of anopheline mosquitoes (Diptera: Culicidae) in relation to climate variables and malaria incidence. A total of 3685 female anopheline mosquitoes, representing six species, were collected. The most abundant species were Anopheles marajoara Galvão & Damasceno (60.7%) and Anopheles darlingi Root (35.1%), which together represented 95.8% of the total anophelines collected. Abundance and species distribution varied by locality. Malaria prevalence varied from 12.5 to 21.4 cases per 1000 population. Transmission occurred throughout the year; the annual parasite index (API) for the study period was 813.0 cases per 1000 population, with a range of 71.6-2492 per 1000 population, depending on locality. Plasmodium vivax (Grassi & Feletti) (Coccidia: Plasmodiidae) accounted for 78.6% of cases, Plasmodium falciparum (Welch) for 21.4% and mixed infections (Pv+Pf) for 0.05) between mosquito abundance and rainfall. Correlations between malaria incidence by parasite species and mosquito abundance were not significant (P > 0.05). Monthly parous rates were similar for An. marajoara and An. darlingi throughout the year, with two peaks that coincided with the dry-rainy transition period and the period of less rain. Peaks in the incidence of malaria cases were observed 1 month after major peaks in biting rates of parous anophelines. Anopheles darlingi engages in biting activity throughout the night, with two minor peaks at 23.00-00.00 hours and 03.00-04.00 hours. Anopheles marajoara has a different pattern, with a biting peak at 19.00-21.00 hours and 76.6% of biting occurring before midnight. Although both vectors bite indoors and outdoors, they showed a highly significant (P < 0.01) degree of exophagic behaviour. The present study constitutes the first effort to characterize the

  7. Orion A helium abundance

    International Nuclear Information System (INIS)

    Tsivilev, A.P.; Ershov, A.A.; Smirnov, G.T.; Sorochenko, R.L.

    1986-01-01

    The 22.4-GHz (H,He)66-alpha and 36.5-GHz (H,He)56-alpha radio recombination lines have been observed at several Jaffe-Pankonin positions in the central part of the Orion A source. The measured relative abundance of ionized helium increases with distance, averaging 11.6 percent at peripheral points. The observed behavior is interpreted by a blister-type model nebula, which implies that Orion A has a true He abundance of 12 percent, is moving with a radial velocity of 5 km/sec, and is expanding. 18 references

  8. Variation in water-use efficiency and its relation to carbon isotope ratio in cotton

    International Nuclear Information System (INIS)

    Saranga, Y.; Flash, I.; Yakir, D.

    1998-01-01

    Cotton (Gossypium spp.) is often exposed to drought, which adversely affects both yield and quality. Improved water-use efficiency (WUE = total dry matter produced or yield harvested / water used) is expected to reduce these adverse effects. Genetic variability in WUE and its association with photosynthetic rate and carbon isotope ratio (13C/12C) in cotton are reported in this paper. WUE of six cotton cultivars--G. hirsutum L., G. barbadense L., and an interspecific F1 hybrid (G. hirsutum x G. barbadense, ISH), was examined under two irrigation regimes in two field trials. The greatest WUE was obtained by two G. hirsutum cultivars (2.55 g dry matter or 1.12 g seed-cotton L-1 H2O) the ISH obtained similar or somewhat lower values, and that G. barbadense cultivars and one G. hirsutum cultivar exhibited the lowest values (2.1 g dry matter or 0.8 to 0.85 g seed-cotton L-1 H2O). These results indicate that different cotton cultivars may have evolved different environmental adaptations that affect their WUE. Photosynthetic rate was correlated with WUE in only a few cases emphasizing the limitation of this parameter as a basis for estimating crop WUE. Under both trials WUE was positively correlated with carbon isotope ratio, indicating the potential of this technique as a selection criterion for improving cotton WUE

  9. Technical note: An inverse method to relate organic carbon reactivity to isotope composition from serial oxidation

    Directory of Open Access Journals (Sweden)

    J. D. Hemingway

    2017-11-01

    Full Text Available Serial oxidation coupled with stable carbon and radiocarbon analysis of sequentially evolved CO2 is a promising method to characterize the relationship between organic carbon (OC chemical composition, source, and residence time in the environment. However, observed decay profiles depend on experimental conditions and oxidation pathway. It is therefore necessary to properly assess serial oxidation kinetics before utilizing decay profiles as a measure of OC reactivity. We present a regularized inverse method to estimate the distribution of OC activation energy (E, a proxy for bond strength, using serial oxidation. Here, we apply this method to ramped temperature pyrolysis or oxidation (RPO analysis but note that this approach is broadly applicable to any serial oxidation technique. RPO analysis directly compares thermal reactivity to isotope composition by determining the E range for OC decaying within each temperature interval over which CO2 is collected. By analyzing a decarbonated test sample at multiple masses and oven ramp rates, we show that OC decay during RPO analysis follows a superposition of parallel first-order kinetics and that resulting E distributions are independent of experimental conditions. We therefore propose the E distribution as a novel proxy to describe OC thermal reactivity and suggest that E vs. isotope relationships can provide new insight into the compositional controls on OC source and residence time.

  10. Technical note: An inverse method to relate organic carbon reactivity to isotope composition from serial oxidation

    Science.gov (United States)

    Hemingway, Jordon D.; Rothman, Daniel H.; Rosengard, Sarah Z.; Galy, Valier V.

    2017-11-01

    Serial oxidation coupled with stable carbon and radiocarbon analysis of sequentially evolved CO2 is a promising method to characterize the relationship between organic carbon (OC) chemical composition, source, and residence time in the environment. However, observed decay profiles depend on experimental conditions and oxidation pathway. It is therefore necessary to properly assess serial oxidation kinetics before utilizing decay profiles as a measure of OC reactivity. We present a regularized inverse method to estimate the distribution of OC activation energy (E), a proxy for bond strength, using serial oxidation. Here, we apply this method to ramped temperature pyrolysis or oxidation (RPO) analysis but note that this approach is broadly applicable to any serial oxidation technique. RPO analysis directly compares thermal reactivity to isotope composition by determining the E range for OC decaying within each temperature interval over which CO2 is collected. By analyzing a decarbonated test sample at multiple masses and oven ramp rates, we show that OC decay during RPO analysis follows a superposition of parallel first-order kinetics and that resulting E distributions are independent of experimental conditions. We therefore propose the E distribution as a novel proxy to describe OC thermal reactivity and suggest that E vs. isotope relationships can provide new insight into the compositional controls on OC source and residence time.

  11. [Relative abundance and microhabitat use by the frog Geobatrachus walkeri (Anura: Strabomantidae) in two habitats of Sierra Nevada de Santa Marta, Colombia].

    Science.gov (United States)

    Martínez Baños, Vera; Pacheco Florez, Vanesa; Ramírez-Pinilla, Martha P

    2011-06-01

    Geobatrachus walkeri belongs to a monotypic frog genus endemic to the San Lorenzo area, Sierra Nevada de Santa Marta, Colombia. This species has been categorized as endangered because of its small distribution area and the decline in the extent and quality of its habitat. It inhabits two forest types with different composition and structure, the native secondary forest and a pine plantation (dominated by Pinus patula). To compare the relative abundance and microhabitat use of this species in these habitat types, 30 quadrants/environment were distributed randomly. The individual number, microhabitat use and other aspects of its natural history were registered using visual encounter surveys in both sites, including non-sampled areas in the quadrants. The relative abundance of frogs was significantly different between habitats and among seasons. The highest abundance of G. walkeri relative to the total area was found in the pine plantation, being 2.3 times higher than in the natural forest. More frogs were significantly found during the rainy season; nevertheless, active individuals were also found during the dry season. Significant differences were found in the microhabitat use with respect to the forest type and season. The most frequently microhabitat used in the two forest types was the pine leaf-litter; besides, in the native forest, the microhabitat occupied more frequently presented medium and large size stones. Geobatrachus walkeri is a successful species in pine plantations, associated permanently to its leaf-litter environment where it seems to develop its entire life cycle. The clear modifications in the soils and water, derived from the introduction of the pine plantation in this area, seem not to have negatively affected the conservation and successful maintenance of this species.

  12. Trait-abundance relation in response to nutrient addition in a Tibetan alpine meadow: The importance of species trade-off in resource conservation and acquisition.

    Science.gov (United States)

    Liu, Huiying; Li, Ying; Ren, Fei; Lin, Li; Zhu, Wenyan; He, Jin-Sheng; Niu, Kechang

    2017-12-01

    In competition-dominated communities, traits promoting resource conservation and competitive ability are expected to have an important influence on species relative abundance (SRA). Yet, few studies have tested the trait-abundance relations in the line of species trade-off in resource conservation versus acquisition, indicating by multiple traits coordination. We measured SRA and key functional traits involving leaf economic spectrum (SLA, specific leaf area; LDMC, leaf dry matter content; LCC, leaf carbon concentration; LNC, leaf nitrogen concentration; LPC, leaf phosphorus concentration; Hs, mature height) for ten common species in all plots subjected to addition of nitrogen fertilizer (N), phosphorus fertilizer (P), or both of them (NP) in a Tibetan alpine meadow. We test whether SRA is positively related with traits promoting plant resource conservation, while negatively correlated with traits promoting plant growth and resource acquisition. We found that species were primarily differentiated along a trade-off axis involving traits promoting nutrient acquisition and fast growth (e.g., LPC and SLA) versus traits promoting resource conservation and competition ability (e.g., large LDMC). We further found that SRA was positively correlated with plant height, LDMC, and LCC, but negatively associated with SLA and leaf nutrient concentration irrespective of fertilization. A stronger positive height-SRA was found in NP-fertilized plots than in other plots, while negative correlations between SRA and SLA and LPC were found in N or P fertilized plots. The results indicate that species trade-off in nutrient acquisition and resource conservation was a key driver of SRA in competition-dominated communities following fertilization, with the linkage between SRA and traits depending on plant competition for specific soil nutrient and/or light availability. The results highlight the importance of competitive exclusion in plant community assembly following fertilization and

  13. Relative probabilities of the uranium isotopes for thorium x-ray emission and fluorescence of uranium x-rays

    International Nuclear Information System (INIS)

    Parker, J.L.

    1991-01-01

    Both thorium x-rays from decaying uranium isotopes and self-fluoresced uranium x-rays are prominent in high-resolution gamma-ray spectra of uranium-bearing materials. Useful application of the information carried by those x-rays has been curtailed because the probabilities of the uranium isotopes for thorium x-ray emission and for uranium x-ray fluorescence have not been known. By analyzing enrichment-meter geometry spectra from uranium oxide standards whose enrichments ranged from 0.7% to 91%, relative values, primarily, have been obtained for the probabilities of both processes. Thorium x-ray emission is very heavily dominated by 235 U. In all ordinarily occurring uranium isotopic distributions, thorium x-rays may be used as a valid 235 U signature. The probability for a thorium K α1 x-ray to be emitted in the decay of a 235 U atom is 0.048 ±0.002. In infinitely thick uranium oxide materials, the relative ratios of effectiveness for self-fluorescence, on a per unit mass basis, are approximately 234 U : 235 U : 236 U : 238 U = 1.13 : 1.00 : 0.52 : 0.028. on a per decay basis, the approximate ratios are 0.00039 : 1.00 : 0.017 : 0.18. These results imply that, contrary to what has often been stated, gamma rays are far more important than alpha particles in the self-fluorescence of uranium. Because of the importance of gamma-ray self-fluorescence, the uranium x-ray yield will be somewhat influenced by the size, shape, and composition of the materials. 4 refs., 1 fig

  14. Conventional oil and natural gas infrastructure increases brown-headed cowbird (Molothrus ater) relative abundance and parasitism in mixed-grass prairie.

    Science.gov (United States)

    Bernath-Plaisted, Jacy; Nenninger, Heather; Koper, Nicola

    2017-07-01

    The rapid expansion of oil and natural gas development across the Northern Great Plains has contributed to habitat fragmentation, which may facilitate brood parasitism of ground-nesting grassland songbird nests by brown-headed cowbirds ( Molothrus ater ), an obligate brood parasite, through the introduction of perches and anthropogenic edges. We tested this hypothesis by measuring brown-headed cowbird relative abundance and brood parasitism rates of Savannah sparrow ( Passerculus sandwichensis ) nests in relation to the presence of infrastructure features and proximity to potential perches and edge habitat. The presence of oil and natural gas infrastructure increased brown-headed cowbird relative abundance by a magnitude of four times, which resulted in four times greater brood parasitism rates at infrastructure sites. While the presence of infrastructure and the proximity to roads were influential in predicting brood parasitism rates, the proximity of perch sites was not. This suggests that brood parasitism associated with oil and natural gas infrastructure may result in additional pressures that reduce productivity of this declining grassland songbird.

  15. Relative importance of plant-mediated bottom-up and top-down forces on herbivore abundance on Brassica oleracea

    NARCIS (Netherlands)

    Kos, M.; Broekgaarden, C.; Kabouw, P.; Oude Lenferink, K.; Poelman, E.H.; Vet, L.E.M.; Dicke, M.; Loon, van J.J.A.

    2011-01-01

    1. Arthropod communities are structured by complex interactions between bottom-up (resource-based) and top-down (natural enemy-based) forces. Their relative importance in shaping arthropod communities, however, continues to be under debate. Bottom-up and top-down forces can be affected by

  16. Using cosmogenic isotopes to measure basin-scale rates of erosion

    International Nuclear Information System (INIS)

    Bierman, P.R.; Steig, E.

    1992-01-01

    The authors present a new and different approach to interpreting the abundance of in situ-produced cosmogenic nuclides such as 36 Cl, 26 Al, and 10 Be. Unlike most existing models, which are appropriate for evaluating isotope concentrations on bedrock surfaces, this model can be used to interpret isotope concentration in fluvial sediment. Because sediment is a mixture of material derived from the entire drainage basin, measured isotope abundances can be used to estimate spatially-averaged rates of erosion and sediment transport. Their approach has the potential to provide geomorphologists with a relatively simple but powerful means by which to constrain rates of landscape evolution. The model considers the flux of cosmogenic isotopes into and out of various reservoirs. Implicit in model development are the assumptions that a geomorphic steady-state has been reached and that sampled sediment is spatially and temporally representative of all sediment leaving the basin. Each year, the impinging cosmic-ray flux produces a certain quantity of cosmogenic isotopes in the rock and soil of a drainage basin. For a basin in steady state, the outgoing isotope flux is also constant. They solve for the rate of mass loss as a function of isotope abundance in the sediment, the cosmic ray attenuation length, the isotope half life, and the effective isotope production rate. There are only a few published measurements of cosmogenic isotope abundance in sediment. They calculated model denudation rates for sediment samples from Zaire and central Texas. The denudation rates they calculated appear reasonable and are similar to those they have measured directly on granite landforms in Georgia and southeastern California and those calculated for the Appalachian Piedmont

  17. 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

  18. 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

  19. The relation of plasma octopamine to hepatic encephalopathy studied with stable isotope dilution technique

    International Nuclear Information System (INIS)

    Zhang Jianhua

    1992-01-01

    In order to investigate the relationship between octopamine and hepatic encephalopathy, plasma octopamine content of normal adults and hepatic patients (compensated or de-compensated cirrhotic, patients with encephalopathy) were determined with isotope dilution and GCMS technique, 200 ng of [1, 1-D]-octopamine was added to each sample as internal standard. After the de-proteinized plasma was subjected to cation exchange chromatography, the amine fraction was derivatized with PFP and analyzed with GCMS using the selected ion monitoring technique. The result showed that the level of plasma octopamine was significantly elevated in patients with encephalopathy. Since this method is sensitive and specific, it is readily applicable to the analysis of a few nano grams of octopamine

  20. Age- and Activity-Related Differences in the Abundance of Myosin Essential and Regulatory Light Chains in Human Muscle

    Directory of Open Access Journals (Sweden)

    James N. Cobley

    2016-04-01

    Full Text Available Traditional methods for phenotyping skeletal muscle (e.g., immunohistochemistry are labor-intensive and ill-suited to multixplex analysis, i.e., assays must be performed in a series. Addressing these concerns represents a largely unmet research need but more comprehensive parallel analysis of myofibrillar proteins could advance knowledge regarding age- and activity-dependent changes in human muscle. We report a label-free, semi-automated and time efficient LC-MS proteomic workflow for phenotyping the myofibrillar proteome. Application of this workflow in old and young as well as trained and untrained human skeletal muscle yielded several novel observations that were subsequently verified by multiple reaction monitoring (MRM. We report novel data demonstrating that human ageing is associated with lesser myosin light chain 1 content and greater myosin light chain 3 content, consistent with an age-related reduction in type II muscle fibers. We also disambiguate conflicting data regarding myosin regulatory light chain, revealing that age-related changes in this protein more closely reflect physical activity status than ageing per se. This finding reinforces the need to control for physical activity levels when investigating the natural process of ageing. Taken together, our data confirm and extend knowledge regarding age- and activity-related phenotypes. In addition, the MRM transitions described here provide a methodological platform that can be fine-tuned to suite multiple research needs and thus advance myofibrillar phenotyping.

  1. On the impact of helium abundance on the Cepheid period-luminosity and Wesenheit relations and the distance ladder

    Science.gov (United States)

    Carini, R.; Brocato, E.; Raimondo, G.; Marconi, M.

    2017-08-01

    This work analyses the effect of the helium content on synthetic period-luminosity relations (PLRs) and period-Wesenheit relations (PWRs) of Cepheids and the systematic uncertainties on the derived distances that a hidden population of He-enhanced Cepheids may generate. We use new stellar and pulsation models to build a homogeneous and consistent framework to derive the Cepheid features. The Cepheid populations expected in synthetic colour-magnitude diagrams of young stellar systems (from 20 to 250 Myr) are computed in several photometric bands for Y = 0.25 and 0.35, at a fixed metallicity (Z = 0.008). The PLRs appear to be very similar in the two cases, with negligible effects (few per cent) on distances, while PWRs differ somewhat, with systematic uncertainties in deriving distances as high as ˜ 7 per cent at log P Statistical effects due to the number of variables used to determine the relations contribute to a distance systematic error of the order of few percent, with values decreasing from optical to near-infrared bands. The empirical PWRs derived from multiwavelength data sets for the Large Magellanic Cloud (LMC) is in a very good agreement with our theoretical PWRs obtained with a standard He content, supporting the evidence that LMC Cepheids do not show any He effect.

  2. Stellar Oxygen Abundances

    Science.gov (United States)

    King, Jeremy

    1994-04-01

    This dissertation addresses several issues concerning stellar oxygen abundances. The 7774 {\\AA} O I triplet equivalent widths of Abia & Rebolo [1989, AJ, 347, 186] for metal-poor dwarfs are found to be systematically too high. I also argue that current effective temperatures used in halo star abundance studies may be ~150 K too low. New color-Teff relations are derived for metal-poor stars. Using the revised Teff values and improved equivalent widths for the 7774A O I triplet, the mean [O/Fe] ratio for a handful of halo stars is found to be +0.52 with no dependence on Teff or [Fe/H]. Possible cosmological implications of the hotter Teff scale are discussed along with additional evidence supporting the need for a higher temperature scale for metal-poor stars. Our Teff scale leads to a Spite Li plateau value of N(Li)=2.28 +/- 0.09. A conservative minimal primordial value of N(Li)=2.35 is inferred. If errors in the observations and models are considered, consistency with standard models of Big Bang nucleosynthesis is still achieved with this larger Li abundance. The revised Teff scale raises the observed B/Be ratio of HD 140283 from 10 to 12, making its value more comfortably consistent with the production of the observed B and Be by ordinary spallation. Our Teff values are found to be in good agreement with values predicted from both the Victoria and Yale isochrone color-Teff relations. Thus, it appears likely that no changes in globular cluster ages would result. Next, we examine the location of the break in the [O/Fe] versus [Fe/H] plane in a quantitative fashion. Analysis of a relatively homogeneous data set does not favor any unique break point in the range -1.7 /= -3), in agreement with the new results for halo dwarfs. We find that the gap in the observed [O/H] distribution, noted by Wheeler et al. [1989, ARAA, 27, 279], persists despite the addition of more O data and may betray the occurrence of a hiatus in star formation between the end of halo formation and

  3. Laboratory training manual on the use of isotopes and radiation in soil-plant relations research

    International Nuclear Information System (INIS)

    1964-01-01

    The International Atomic Energy Agency (IAEA) and the Food and Agriculture Organization of the United Nations (FAO) in co-operation with local authorities in various countries have jointly sponsored international laboratory training courses on the use of isotopes and radiation in specialized fields of agriculture. Outstanding scientists from various countries have given lectures and devised and conducted the laboratory exercises; research workers from all over the world have attended these courses. In addition, under the United Nations Expanded Programme of Technical Assistance the IAEA in co-operation with host governments has conducted similar regional courses. This laboratory manual is a natural outgrowth of these activities. The contents represents the efforts not only of the IAEA and FAO Secretariats but also of the various instructors who have participated in the courses, a Special Consultant, Victor Middelboe, and a panel of scientists who met in Vienna from 3 to 7 September 1962 and revised the initial version assembled by Hans Broeshart and Chai Moo Cho of the IAEA Secretariat. The present manual consists of two parts: a basic part which contains general information and laboratory exercises on the properties of radiation and the principles of use of radioactive tracers, and a second part which contains a series of detailed laboratory exercises in the field of soil-plant relationships. It is intended to publish at least four additional parts on the subjects of the use of isotopes and radiation in animal science, agricultural biochemistry, entomology and plant pathology. This manual, dealing with an important aspect of the peaceful application and use of atomic energy, should prove helpful not only to those working with the IAEA and FAO training programmes but to other research scientists dealing with the development and use of new information in agricultural science all over the world

  4. Relative Abundances of Candida albicans and Candida glabrata in In Vitro Coculture Biofilms Impact Biofilm Structure and Formation.

    Science.gov (United States)

    Olson, Michelle L; Jayaraman, Arul; Kao, Katy C

    2018-04-15

    Candida is a member of the normal human microbiota and often resides on mucosal surfaces such as the oral cavity or the gastrointestinal tract. In addition to their commensality, Candida species can opportunistically become pathogenic if the host microbiota is disrupted or if the host immune system becomes compromised. An important factor for Candida pathogenesis is its ability to form biofilm communities. The two most medically important species- Candida albicans and Candida glabrata -are often coisolated from infection sites, suggesting the importance of Candida coculture biofilms. In this work, we report that biofilm formation of the coculture population depends on the relative ratio of starting cell concentrations of C. albicans and C. glabrata When using a starting ratio of C. albicans to C. glabrata of 1:3, ∼6.5- and ∼2.5-fold increases in biofilm biomass were observed relative to those of a C. albicans monoculture and a C. albicans / C. glabrata ratio of 1:1, respectively. Confocal microscopy analysis revealed the heterogeneity and complex structures composed of long C. albicans hyphae and C. glabrata cell clusters in the coculture biofilms, and reverse transcription-quantitative PCR (qRT-PCR) studies showed increases in the relative expression of the HWP1 and ALS3 adhesion genes in the C. albicans / C. glabrata 1:3 biofilm compared to that in the C. albicans monoculture biofilm. Additionally, only the 1:3 C. albicans / C. glabrata biofilm demonstrated an increased resistance to the antifungal drug caspofungin. Overall, the results suggest that interspecific interactions between these two fungal pathogens increase biofilm formation and virulence-related gene expression in a coculture composition-dependent manner. IMPORTANCE Candida albicans and Candida glabrata are often coisolated during infection, and the occurrence of coisolation increases with increasing inflammation, suggesting possible synergistic interactions between the two Candida species in

  5. Constrained Maximum Likelihood Estimation of Relative Abundances of Protein Conformation in a Heterogeneous Mixture from Small Angle X-Ray Scattering Intensity Measurements

    Science.gov (United States)

    Onuk, A. Emre; Akcakaya, Murat; Bardhan, Jaydeep P.; Erdogmus, Deniz; Brooks, Dana H.; Makowski, Lee

    2015-01-01

    In this paper, we describe a model for maximum likelihood estimation (MLE) of the relative abundances of different conformations of a protein in a heterogeneous mixture from small angle X-ray scattering (SAXS) intensities. To consider cases where the solution includes intermediate or unknown conformations, we develop a subset selection method based on k-means clustering and the Cramér-Rao bound on the mixture coefficient estimation error to find a sparse basis set that represents the space spanned by the measured SAXS intensities of the known conformations of a protein. Then, using the selected basis set and the assumptions on the model for the intensity measurements, we show that the MLE model can be expressed as a constrained convex optimization problem. Employing the adenylate kinase (ADK) protein and its known conformations as an example, and using Monte Carlo simulations, we demonstrate the performance of the proposed estimation scheme. Here, although we use 45 crystallographically determined experimental structures and we could generate many more using, for instance, molecular dynamics calculations, the clustering technique indicates that the data cannot support the determination of relative abundances for more than 5 conformations. The estimation of this maximum number of conformations is intrinsic to the methodology we have used here. PMID:26924916

  6. Space-time variation of the relative abundance of Limnoperna fortunei in deep zones of São Gonçalo Channel, Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Michelle Lopes

    Full Text Available This work describes the spatial-temporal variation of the relative abundance and size of Limnoperna fortunei (Dunker, 1857 collected in São Gonçalo Channel through bottom trawl with a 0.5 cm mesh, at depths between 3 and 6 m. The estimative of mean relative abundance (CPUE ranged from 2,425.3 individuals per drag (ind./drag in the spring to 21,715.0 ind./drag in the fall, with an average of 9,515.3 ind./drag throughout the year. The estimated mean density of L. fortunei for the deep region of São Gonçalo Channel ranged from 1.2 to 10.3 ind./m², and it was recorded a maximum density of 84.9 ind./m² in the fall of 2008. The method of sampling using bottom trawl enabled the capture of L. fortunei under the soft muddy bottom of the channel, in different sizes ranging from 0.4 to 3.2 cm. This shows that the structure of the L. fortunei adult population under the bottom of the São Gonçalo Channel is composed mostly of small individuals (<1.4 cm, which represent up to 74% of the population collected.

  7. MULTIPLE ORIGINS OF NITROGEN ISOTOPIC ANOMALIES IN METEORITES AND COMETS

    International Nuclear Information System (INIS)

    Aleon, Jerome

    2010-01-01

    Isotopic fractionation and mixing calculations compared with coupled hydrogen and nitrogen isotopic composition of organic molecules from primitive chondrites, interplanetary dust particles (IDPs), and comets C/1995 O1 (Hale-Bopp) and 81P/Wild2 reveal that meteoritic and cometary organic matter contains three different isotopic components of different origins. (1) A major component of carbonaceous chondrites, IDPs, and comets Hale-Bopp and Wild2 shows correlated H and N isotopic compositions attributable to isotope exchange between an organic matter of solar composition and a reservoir formed by ion-molecule reactions at T 15 N-rich component having identical 15 N and D enrichments relative to the protosolar gas. Temperatures > 100 K deduced from the low D/H ratio and an anti-correlation between the abundance of this component and meteoritic age indicate a late origin in the solar protoplanetary disk. N 2 self-shielding and the non-thermal nucleosynthesis of 15 N upon irradiation are possible but unlikely sources of this component, and a chemical origin is preferred. (3) An interstellar component with highly fractionated hydrogen isotopes and unfractionated nitrogen isotopes is present in ordinary chondrites. A dominantly solar origin of D and 15 N excesses in primitive solar system bodies shows that isotopic anomalies do not necessarily fingerprint an interstellar origin and implies that only a very small fraction of volatile interstellar matter survived the events of solar system formation.

  8. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2009-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeolimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteroic waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 56 refs., 11 figs., 2 tabs.

  9. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2014-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author)

  10. Stable isotope geochemistry: definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2015-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author).

  11. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2012-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 89 refs., 12 figs., 2 tabs.

  12. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2008-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeolimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteroic waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 56 refs., 11 figs., 2 tabs

  13. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2009-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeolimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteroic waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 56 refs., 11 figs., 2 tabs

  14. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2016-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author).

  15. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2013-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 91 refs., 12 figs., 2 tabs.

  16. 13C-isotopic fingerprint of Pinus pinaster Ait. and Pinus sylvestris L. wood related to the quality of standing tree mass in forests from NW Spain.

    Science.gov (United States)

    Fernandez, Irene; González-Prieto, Serafin J; Cabaneiro, Ana

    2005-01-01

    Pine forest plantations of Pinus pinaster Ait. and P. sylvestris L. located in Galicia, NW Spain, were selected to study the 13C/12C-isotopic fingerprint in wood core samples in order to find possible relationships between the delta(13)C at natural abundance levels and the quality of the standing tree mass. For each pine species, 24 forests growing on acidic soils were studied: half developed over granite and half over schists. Two dominant trees from each plot, corresponding to all possible combinations of forest stands with high or low site index and with adults or young trees, were drilled at the basal part of trunks using a Pressler drill to obtain tree ring samples. The C-isotopic compositions of the litter and the soil organic matter from different soil depths were also determined and statistically significant correlations between these values and the 13C content of the wood were observed. Despite internal variations due to the influence of site index, tree age and parent material, the isotopic fingerprint of P. pinaster wood (mean value delta13C=-26.2+/-0.8 per thousand) significantly differed (Ppinaster stands (r=-0.667, Ppinaster growing over schists (r=-0.833, Ppinaster trees is higher when plots over granite or schists are separately considered. A similar fact occurs for adult P. sylvestris trees from schists stands, high quality specimens being 13C-depleted compared with low quality ones. On the other hand, 13C natural abundance of wood from P. sylvestris trees seems to be also strongly influenced by the underlying parent material, young trees from granite stands having a statistically higher 13C-isotopic composition (P<0.05) than young trees from schists stands. Copyright (c) 2005 John Wiley & Sons, Ltd.

  17. Isotopic composition of cosmic ray nuclei

    International Nuclear Information System (INIS)

    Enge, W.

    1976-01-01

    A review will be given on the role of cosmic ray isotopes as tracers of the astrophysical nucleo-synthesis. The products of every nuclear burning chain are first of all isotopes and not elements. Thus, it is the study of the isotopes rather than that of the elements that responds to the questions on these nucleo-synthetic reactions. The problems concerning the solar system isotopic abundances and the cosmic ray isotopic abundances as well as a comparison between both will be presented. Furthermore the present stage of the experimental techniques and the latest results will be discussed. (orig.) [de

  18. Abundance and activity of soil microorganisms in Cedrus atlantica forests are more related to land use than to altitude or latitude

    Science.gov (United States)

    Ramírez Rojas, Irene; Perez Fernandez, María; Moreno Gallardo, Laura; Lechuga Ordoñez, Victor; Linares, Juan Carlos

    2016-04-01

    Several environmental traits might change the abundance and the function of soil microorganisms in forest soils by plant-mediated reactions. Few studies have related the landscape-scale forest structural diversity with the micro-scale distribution of microorganism and their activities. High mountain environments harbor ecosystems that are very sensitive to global change and hence highly vulnerable, as those of Atlantic cedar. Altitudinal gradients in mountains are orrelated with changes in vegetation. We propose that altitudinal gradients drive shifts in microbial communities and are correlated with land uses. Thus, the latitudinal and longitudinal pattern of abundance and activity of soil micro-organisms was studied in an intercontinental comparison. We investigate soil extractable organic carbon (EOC) and nitrogen and carbon, microbial biomass and microbial metabolic activities at eight different sites along the latitudinal range of Cedrus atlantica, covering different altitudes and soils characteristics both in Southern Spain and Northern Morocco. Analyses of the abundances of total bacteria, (16S rRNA gene), was conducted using the Ilumina metagenomics technique. Results show that the stands at the highest altitudes had distinct microbial and biochemical characteristics compared with other areas. Overall, microbial activity, as measured by soil respiration, is higher in forests subjected to lower human pressure than in stands highly degraded, probably reflecting the quality of litter input that results of the influence of local assemblage of different tree, shrub and annual species, though changes in the soil N and C contents. Indeed, total soil C and N contents explained the microbial properties at every scale. Our results suggest that in contrast to the observed pronounced altitudinal changes, the kind of human-mediate land management has a stronger role in defining changes in microbial composition and activities in the investigated forest systems.

  19. Relative abundance of PcP energy in explosion seismic signals from Eastern Kazakh and South Western Russia recorded at Eskdalemuir, Yellowknife and Gauribidanur arrays

    International Nuclear Information System (INIS)

    Basu, T.K.; Arora, S.K.

    1991-01-01

    In this study further evidence of relative abundance of PcP (core reflected P) energy in explosion seismic records is gathered. It is based on the analysis of temporal and spectral characteristics of P and PcP digital seismograms of twenty-three underground nuclear explosions in Eastern Kazakh and Southern Russia recorded at Eskdalemuir (EKA) and Yellowkinfe (YKA) arrays. The results are compared with those obtained earlier using Gauribidanur array (GBA) data. It is found that seismic sources in Southwestern Russia give consistently large values of the PcP identifier when both EKA and YKA data are used thus corroborating authors' earlier finding with regard to this Soviet region of typical Q-structure inferred from GBA data. As regards relative levels of PcP energy in explosion generated seismic waves, it is found to be substantially large at GBA, moderate at YKA and least at EKA. (author). 8 figs., 3 tabs

  20. Proposed Method for Estimating Health-Promoting Glucosinolates and Hydrolysis Products in Broccoli (Brassica oleracea var. italica) Using Relative Transcript Abundance.

    Science.gov (United States)

    Becker, Talon M; Jeffery, Elizabeth H; Juvik, John A

    2017-01-18

    Due to the importance of glucosinolates and their hydrolysis products in human nutrition and plant defense, optimizing the content of these compounds is a frequent breeding objective for Brassica crops. Toward this goal, we investigated the feasibility of using models built from relative transcript abundance data for the prediction of glucosinolate and hydrolysis product concentrations in broccoli. We report that predictive models explaining at least 50% of the variation for a number of glucosinolates and their hydrolysis products can be built for prediction within the same season, but prediction accuracy decreased when using models built from one season's data for prediction of an opposing season. This method of phytochemical profile prediction could potentially allow for lower phytochemical phenotyping costs and larger breeding populations. This, in turn, could improve selection efficiency for phase II induction potential, a type of chemopreventive bioactivity, by allowing for the quick and relatively cheap content estimation of phytochemicals known to influence the trait.

  1. ICT: isotope correction toolbox.

    Science.gov (United States)

    Jungreuthmayer, Christian; Neubauer, Stefan; Mairinger, Teresa; Zanghellini, Jürgen; Hann, Stephan

    2016-01-01

    Isotope tracer experiments are an invaluable technique to analyze and study the metabolism of biological systems. However, isotope labeling experiments are often affected by naturally abundant isotopes especially in cases where mass spectrometric methods make use of derivatization. The correction of these additive interferences--in particular for complex isotopic systems--is numerically challenging and still an emerging field of research. When positional information is generated via collision-induced dissociation, even more complex calculations for isotopic interference correction are necessary. So far, no freely available tools can handle tandem mass spectrometry data. We present isotope correction toolbox, a program that corrects tandem mass isotopomer data from tandem mass spectrometry experiments. Isotope correction toolbox is written in the multi-platform programming language Perl and, therefore, can be used on all commonly available computer platforms. Source code and documentation can be freely obtained under the Artistic License or the GNU General Public License from: https://github.com/jungreuc/isotope_correction_toolbox/ {christian.jungreuthmayer@boku.ac.at,juergen.zanghellini@boku.ac.at} Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Seasonal changes in the abundance of bacterial genes related to dimethylsulfoniopropionate catabolism in seawater from Ofunato Bay revealed by metagenomic analysis

    KAUST Repository

    Kudo, Toshiaki

    2018-04-26

    Ofunato Bay is located in the northeastern Pacific Ocean area of Japan, and it has the highest biodiversity of marine organisms in the world, primarily due to tidal influences from the cold Oyashio and warm Kuroshio currents. Our previous results from performing shotgun metagenomics indicated that Candidatus Pelagibacter ubique and Planktomarina temperata were the dominant bacteria (Reza et al., 2018a, 2018b). These bacteria are reportedly able to catabolize dimethylsulfoniopropionate (DMSP) produced from phytoplankton into dimethyl sulfide (DMS) or methanethiol (MeSH). This study was focused on seasonal changes in the abundances of bacterial genes (dddP, dmdA) related to DMSP catabolism in the seawater of Ofunato Bay by BLAST+ analysis using shotgun metagenomic datasets. We found seasonal changes among the Candidatus Pelagibacter ubique strains, including those of the HTCC1062 type and the Red Sea type. A good correlation was observed between the chlorophyll a concentrations and the abundances of the catabolic genes, suggesting that the bacteria directly interact with phytoplankton in the marine material cycle system and play important roles in producing DMS and MeSH from DMSP as signaling molecules for the possible formation of the scent of the tidewater or as fish attractants.

  3. Seasonal changes in the abundance of bacterial genes related to dimethylsulfoniopropionate catabolism in seawater from Ofunato Bay revealed by metagenomic analysis

    KAUST Repository

    Kudo, Toshiaki; Kobiyama, Atsushi; Rashid, Jonaira; Reza, Shaheed; Yamada, Yuichiro; Ikeda, Yuri; Ikeda, Daisuke; Mizusawa, Nanami; Ikeo, Kazuho; Sato, Shigeru; Ogata, Takehiko; Jimbo, Mitsuru; Kaga, Shinnosuke; Watanabe, Shiho; Naiki, Kimiaki; Kaga, Yoshimasa; Segawa, Satoshi; Mineta, Katsuhiko; Bajic, Vladimir B.; Gojobori, Takashi; Watabe, Shugo

    2018-01-01

    Ofunato Bay is located in the northeastern Pacific Ocean area of Japan, and it has the highest biodiversity of marine organisms in the world, primarily due to tidal influences from the cold Oyashio and warm Kuroshio currents. Our previous results from performing shotgun metagenomics indicated that Candidatus Pelagibacter ubique and Planktomarina temperata were the dominant bacteria (Reza et al., 2018a, 2018b). These bacteria are reportedly able to catabolize dimethylsulfoniopropionate (DMSP) produced from phytoplankton into dimethyl sulfide (DMS) or methanethiol (MeSH). This study was focused on seasonal changes in the abundances of bacterial genes (dddP, dmdA) related to DMSP catabolism in the seawater of Ofunato Bay by BLAST+ analysis using shotgun metagenomic datasets. We found seasonal changes among the Candidatus Pelagibacter ubique strains, including those of the HTCC1062 type and the Red Sea type. A good correlation was observed between the chlorophyll a concentrations and the abundances of the catabolic genes, suggesting that the bacteria directly interact with phytoplankton in the marine material cycle system and play important roles in producing DMS and MeSH from DMSP as signaling molecules for the possible formation of the scent of the tidewater or as fish attractants.

  4. Light regimes differentially affect baseline transcript abundance of stress-axis and (neurodevelopment-related genes in zebrafish (Danio rerio, Hamilton 1822 AB and TL larvae

    Directory of Open Access Journals (Sweden)

    Ruud van den Bos

    2017-11-01

    Full Text Available Many strains of zebrafish (Danio rerio are readily available. Earlier we observed differences between AB and Tupfel long-fin (TL larvae regarding baseline hypothalamus-pituitary-interrenal (HPI axis activity and (neurodevelopment. Light regimes, i.e. 14 h light:10 h dark and 24 h continuous dark or light, affect hatching rate and larval growth. Here, we assessed baseline transcript abundance of HPI-axis-related genes and (neurodevelopment-related genes of AB and TL larvae (5 days post fertilisation using these light regimes. A principal component analysis revealed that in AB larvae the baseline expression of HPI-axis-related genes was higher the more hours of light, while the expression of (neurodevelopment-related genes was higher under 14 h light:10 h dark than under both continuous light or dark. In TL larvae, a complex pattern emerged regarding baseline expression of HPI-axis-related and (neurodevelopment-related genes. These data extend data of earlier studies by showing that light regimes affect gene-expression in larvae, and more importantly so, strengthen the notion of differences between larvae of the AB and TL strain. The latter finding adds to the growing database of phenotypical differences between zebrafish of the AB and TL strain.

  5. Abundances in the Galactic bulge

    Energy Technology Data Exchange (ETDEWEB)

    Barbuy, B; Alves-Brito, A [Universidade de Sao Paulo, IAG, Rua do Matao 1226, Sao Paulo 05508-900 (Brazil); Ortolani, S; Zoccali, M [Dipartimento di Astronomia, Universita di Padova, Vicolo dell' Osservatorio 2, I-35122 Padova (Italy); Hill, V; Gomez, A [Observatoire de Paris-Meudon, 92195 Meudon Cedex (France); Melendez, J [Centro de AstrofIsica da Universidade de Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Asplund, M [Max Planck Institute for Astrophysics, Postfach 1317, 85741 Garching (Germany); Bica, E [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, CP 15051, Porto Alegre 91501-970 (Brazil); Renzini, A [Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Minniti, D [Department of Astronomy and Astrophysics, Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)], E-mail: barbuy@astro.iag.usp.br

    2008-12-15

    The metallicity distribution and abundance ratios of the Galactic bulge are reviewed. Issues raised by recent work of different groups, in particular the high metallicity end, the overabundance of {alpha}-elements in the bulge relative to the thick disc and the measurement of giants versus dwarfs, are discussed. Abundances in the old moderately metal-poor bulge globular clusters are described.

  6. High mass isotope separation arrangement

    International Nuclear Information System (INIS)

    Eerkens, J.W.

    1980-01-01

    This invention relates to the isotope separation art and, more particularly, to a selectively photon-induced energy level transition of an isotopic molecule containing the isotope to be separated and a chemical reaction with a chemically reactive agent to provide a chemical compound containing atoms of the isotope desired. In particular a description is given of a method of laser isotope separation applied to the separation of 235 UF 6 from 238 UF 6 . (U.K.)

  7. Precise and accurate isotope ratio measurements by ICP-MS.

    Science.gov (United States)

    Becker, J S; Dietze, H J

    2000-09-01

    The precise and accurate determination of isotope ratios by inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) is important for quite different application fields (e.g. for isotope ratio measurements of stable isotopes in nature, especially for the investigation of isotope variation in nature or age dating, for determining isotope ratios of radiogenic elements in the nuclear industry, quality assurance of fuel material, for reprocessing plants, nuclear material accounting and radioactive waste control, for tracer experiments using stable isotopes or long-lived radionuclides in biological or medical studies). Thermal ionization mass spectrometry (TIMS), which used to be the dominant analytical technique for precise isotope ratio measurements, is being increasingly replaced for isotope ratio measurements by ICP-MS due to its excellent sensitivity, precision and good accuracy. Instrumental progress in ICP-MS was achieved by the introduction of the collision cell interface in order to dissociate many disturbing argon-based molecular ions, thermalize the ions and neutralize the disturbing argon ions of plasma gas (Ar+). The application of the collision cell in ICP-QMS results in a higher ion transmission, improved sensitivity and better precision of isotope ratio measurements compared to quadrupole ICP-MS without the collision cell [e.g., for 235U/238U approximately 1 (10 microg x L(-1) uranium) 0.07% relative standard deviation (RSD) vs. 0.2% RSD in short-term measurements (n = 5)]. A significant instrumental improvement for ICP-MS is the multicollector device (MC-ICP-MS) in order to obtain a better precision of isotope ratio measurements (with a precision of up to 0.002%, RSD). CE- and HPLC-ICP-MS are used for the separation of isobaric interferences of long-lived radionuclides and stable isotopes by determination of spallation nuclide abundances in an irradiated tantalum target.

  8. The relative abundance of predicted genes associated with ammonia-oxidation, nitrate reduction, and biomass decomposition in mineral soil are altered by intensive timber harvest.

    Science.gov (United States)

    Mushinski, R. M.; Zhou, Y.; Gentry, T. J.; Boutton, T. W.

    2017-12-01

    Forest ecosystems in the southern United States are substantially altered by anthropogenic disturbances such as timber harvest and land conversion, with effects being observed in carbon and nutrient pools as well as biogeochemical processes. Furthermore, the desire to develop renewable energy sources in the form of biomass extraction from logging residues may result in alterations in soil community structure and function. While the impact of forest management on soil physicochemical properties of the region has been studied, its' long-term effect on soil bacterial community composition and metagenomic potential is relatively unknown, especially at deeper soil depths. This study investigates how intensive organic matter removal intensities associated with timber harvest influence decadal-scale alterations in bacterial community structure and functional potential in the upper 1-m of the soil profile, 18 years post-harvest in a Pinus taeda L. forest of eastern Texas. Amplicon sequencing of the 16S rRNA gene was used in conjunction with soil chemical analyses to evaluate treatment-induced differences in community composition and potential environmental drivers of associated change. Furthermore, functional potential was assessed by using amplicon data to make metagenomic predictions. Results indicate that increasing organic matter removal intensity leads to altered community composition and the relative abundance of dominant OTUs annotated to Burkholderia and Aciditerrimonas. The relative abundance of predicted genes associated with dissimilatory nitrate reduction and denitrification were highest in the most intensively harvested treatment while genes involved in nitrification were significantly lower in the most intensively harvested treatment. Furthermore, genes associated with glycosyltransferases were significantly reduced with increasing harvest intensity while polysaccharide lyases increased. These results imply that intensive organic matter removal may create

  9. Functional strategies of tropical dry forest plants in relation to growth form and isotopic composition

    Science.gov (United States)

    Santiago, L. S.; Silvera, K.; Andrade, J. L.; Dawson, T. E.

    2017-11-01

    Tropical dry forests (TDFs) undergo a substantial dry season in which plant species must endure several months of drought. Although TDFs support a diverse array of plant growth forms, it is not clear how they vary in mechanisms for coping with seasonal drought. We measured organic tissue stable isotopic composition of carbon (δ13C) and nitrogen (δ15N) across six plant growth forms including epiphytes, terrestrial succulents, trees, shrubs, herbs, and vines, and oxygen (δ18O) of four growth forms, to distinguish among patterns of resource acquisition and evaluate mechanisms for surviving annual drought in a lowland tropical dry forest in Yucatan, Mexico. Terrestrial succulent and epiphyte δ13C was around -14‰, indicating photosynthesis through the Crassulacean acid metabolism pathway, and along with one C4 herb were distinct from mean values of all other growth forms, which were between -26 and -29‰ indicating C3 photosynthesis. Mean tissue δ15N across epiphytes was -4.95‰ and was significantly lower than all other growth forms, which had values around +3‰. Tissue N concentration varied significantly among growth forms with epiphytes and terrestrial succulents having significantly lower values of about 1% compared to trees, shrubs, herbs and vines, which were around 3%. Tissue C concentration was highest in trees, shrubs and vines, intermediate in herbs and epiphytes and lowest in terrestrial succulents. δ18O did not vary among growth forms. Overall, our results suggest several water-saving aspects of resource acquisition, including the absolute occurrence of CAM photosynthesis in terrestrial succulents and epiphytes, high concentrations of leaf N in some species, which may facilitate CO2 drawdown by photosynthetic enzymes for a given stomatal conductance, and potentially diverse N sources ranging from atmospheric N in epiphytes with extremely depleted δ15N values, and a large range of δ15N values among trees, many of which are legumes and dry season

  10. Relations between oxygen stable isotopic ratios in precipitation and relevant meteorological factors in southwest China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The correlations of isotopic ratios in precipitation with temperature, air pressure and humidity at dif- ferent altitudes, in southwest China, are analyzed. There appear marked negative correlations for the δ 18O in precipitation with precipitation amount, vapor pressure and atmospheric precipitable water (PW) at Mengzi, Simao and Tengchong stations on synoptic timescale; the marked negative correlations between the δ 18O in precipitation and the diurnal mean temperature at 400 hPa, 500 hPa, 700 hPa and 850 hPa are different from the temperature effect in middle-high-latitude inland. Moreover, the notable positive correlation between the δ 18O in precipitation and the dew-point deficit △Td at different altitudes is found at the three stations. On annual timescale, the annual precipitation amount weighted mean δ 18O display the negative correlations not only with annual precipitation but also with annual mean temperature at 500 hPa. It can be deduced that, in the years with abnormally strong summer monsoon, more warm and wet air from low-latitude oceans is transported northward along the vapor channel located in southwest China and generates abnormally strong rainfall on the way. Meanwhile, the ab- normally strong condensation process will release more condensed latent heat into atmosphere, and lead to the rise of atmospheric temperature during rainfall, but decline of the δ 18O in precipitation. On the contrary, in the years with abnormally weak summer monsoon, the abnormally weak condensation process will release less condensed latent heat into atmosphere, and lead to the decline of atmos- pheric temperature during rainfall, but increase of the δ 18O in precipitation.

  11. Krypton isotope analysis using near-resonant stimulated Raman spectroscopy

    International Nuclear Information System (INIS)

    Whitehead, C.A.; Cannon, B.D.; Wacker, J.F.

    1994-12-01

    A method for measuring low relative abundances of 85 Kr in one liter or less samples of air has been under development here at Pacific Northwest Laboratory. The goal of the Krypton Isotope Laser Analysis (KILA) method is to measure ratios of 10 -10 or less of 85 Kr to more abundant stable krypton. Mass spectrometry and beta counting are the main competing technologies used in rare-gas trace analysis and are limited in application by such factors as sample size, counting times, and selectivity. The use of high-resolution lasers to probe hyperfine levels to determine isotopic abundance has received much attention recently. In this study, we report our progress on identifying and implementing techniques for trace 85 Kr analysis on small gas samples in a static cell as well as limitations on sensitivity and selectivity for the technique. High-resolution pulsed and cw lasers are employed in a laser-induced fluorescence technique that preserves the original sample. This technique, is based on resonant isotopic depletion spectroscopy (RIDS) in which one isotope is optically depleted while preserving the population of a less abundant isotope. The KILA method consists of three steps. In the first step, the 1s 5 metastable level of krypton is populated via radiative cascade following two-photon excitation of the 2p 6 energy level. Next, using RBDS, the stable krypton isotopes are optically depleted to the ground state through the 1s 4 level with the bulk of the 85 Kr population being preserved. Finally, the remaining metastable population is probed to determine 85 Kr concentration. The experimental requirements for each of these steps are outlined below

  12. Species composition and relative abundance of sand flies of the genus Lutzomyia (Diptera: Psychodidae) at an endemic focus of visceral leishmaniasis in Colombia.

    Science.gov (United States)

    Ferro, C; Morrison, A C; Torres, M; Pardo, R; Wilson, M L; Tesh, R B

    1995-07-01

    Ecological studies on the sand fly Lutzomyia longipalpis (Lutz & Neiva) were conducted during 1990-1993 at a small rural community in Colombia where American visceral leishmaniasis is endemic. Weekly sand fly collections were made from pigpens, houses, and natural resting sites, using hand-held aspirators, sticky (oiled) paper traps, and opossum-baited Disney traps. In total, 263,094 sand flies were collected; L. longipalpis predominated (86.1%), followed by L. trinidadensis (11.0%), L. cayennensis (2.7%), and 8 other Lutzomyia species. The species composition and sex ratio of these sand flies varied among sites and by collection method. L. longipalpis were captured most efficiently by direct aspiration from animal bait. Conversely, sticky paper traps, especially inside houses and at rock resting sites, collected a greater diversity of species, but a lower relative abundance of L. longipalpis.

  13. Neodymium and strontium isotopic stratigraphy of the neo-archean Rio Jacare Sill-Bahia, Brazil and its relation to PGE mineralization

    International Nuclear Information System (INIS)

    Brito, Reinaldo S.C de; Pimentel, Marcio M.; Nilson, Ariplinio A.; Gioia, Simone M

    2001-01-01

    Platinum-Group Elements (PGE) deposition in magma chambers is generally accepted as being triggered by sulphur immiscibility via sulfidasation and/or felsification of magmas. These processes can be related to fractional crystallization, and mixing of batches of magmas, crustal contamination or by the combination of these process. Important isotopic studies have been carried out by many authors such as Lambert (1989) and Marcantonio (1995) in the Stillwater Complex, Kruger and Marsh (1989) and Cawthorn (1996) in the Bushveld Complex. Those works set out to understand the role of isotopic changes in the genesis of PGE deposits from JM and Merensky Reefs, respectively. They attributed those PGE mineralizations to isotopically constrained mixing/contamination episodes associated to subtle changes in steady vertical fractionation trends. This work presents stratigraphycally-plotted Nd and Sr isotopic data together with evidence of mineral and whole rock geochemistry disturbance in smooth fractionations trends of the Rio Jacare Sill. Data interpretation suggest the sill was formed via fractional crystallisation and mixing of at least three magma batches, combined with some degree of host rocks assimilation. Isotopic changes were also related to PGE anomalies associated with transitional facies formed during such mixing episodes (au)

  14. Diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest in the Isthmus of Tehuantepec, Oaxaca, Mexico

    Directory of Open Access Journals (Sweden)

    Malinalli Cortés-Marcial

    2014-12-01

    Full Text Available The use of camera traps and mammal track search are complementary methods to monitoring species of which is not well documented their natural history, as in the case of medium and large mammals. To ensure its conservation and good management, it is necessary to generate information about the structure of the community and their populations. The objective of the present study was to estimate the diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest located in the Isthmus of Tehuantepec, Oaxaca, Mexico. Samplings were conducted in three month intervals, from September 2011 to May 2013. We used photographic-sampling and track search, two complementary sampling methods. For photographic-sampling, 12 camera traps were placed covering an area of 60km², while for the tracks search a monthly tour of four line-transect surveys of three kilometers length each was undertaken. We obtained a total of 344 pictures with 5 292 trap-days total sampling effort; in addition, 187 track records in a total of 144km. With both methods we registered 21 species of mammals, in 13 families and seven orders, and five species resulted in new records to the area. The diversity index of Shannon-Wiener obtained with the method of tracks was H´=2.41, while the most abundant species were Urocyon cinereoargenteus (IAR=0.23 and Pecari tajacu (IAR=0.20. By the method of trap the most abundant species were P. tajacu (IAR=2.62 and Nasua narica (IAR=1.28. In terms of patterns of activity P. tajacu, N. narica and Odocoileus virginianus were primarily diurnal species; Canis latrans and Leopardus pardalis did not show preference for any schedule in particular, and Didelphis virginiana and Dasypus novemcinctus preferred to have nocturnal activity. This information can be of help to the creation of programs of management and conservation of mammals of medium and large in the Isthmus of Tehuantepec, Oaxaca, México. Rev. Biol. Trop

  15. [Diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest in the Isthmus of Tehuantepec, Oaxaca, Mexico].

    Science.gov (United States)

    Cortés-Marcial, Malinalli; Briones-Salas, Miguel

    2014-12-01

    The use of camera traps and mammal track search are complementary methods to monitoring species of which is not well documented their natural history, as in the case of medium and large mammals. To ensure its conservation and good management, it is necessary to generate information about the structure of the community and their populations. The objective of the present study was to estimate the diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest located in the Isthmus of Tehuantepec, Oaxaca, Mexico. Samplings were conducted in three month intervals, from September 2011 to May 2013. We used photographic-sampling and track search, two complementary sampling methods. For photographic-sampling, 12 camera traps were placed covering an area of 60 km2, while for the tracks search a monthly tour of four line-transect surveys of three kilometers length each was undertaken. We obtained a total of 344 pictures with 5292 trap-days total sampling effort; in addition, 187 track records in a total of 144 km. With both methods we registered 21 species of mammals, in 13 families and seven orders, and five species resulted in new records to the area. The diversity index of Shannon-Wiener obtained with the method of tracks was H' = 2.41, while the most abundant species were Urocyon cinereoargen- teus (IAR = 0.23) and Pecari tajacu (IAR = 0.20). By the method of trap the most abundant species were P. tajacu (IAR = 2.62) and Nasua narica (IAR = 1.28). In terms of patterns of activity P. tajacu, N. narica and Odocoileus virginianus were primarily diurnal species; Canis latrans and Leopardus pardalis did not show preference for any schedule in particular, and Didelphis virginiana and Dasypus novemcinctus preferred to have nocturnal activity. This information can be of help to the creation of programs of management and conservation of mam- mals of medium and large in the Isthmus of Tehuantepec, Oaxaca, México.

  16. Oxygen isotopic ratios of quartz from wind-erosive soils of southwestern United States in relation to aerosol dust

    Energy Technology Data Exchange (ETDEWEB)

    Sridhar, K.; Jackson, M.L.; Clayton, R.N.; Gillette, D.A.; Hawley, J.W.

    1978-01-01

    The oxygen isotopic ratios (expressed as parts per thousand relative to mean ocean water, SMOW, delta/sup 18/O) of the quartz from 13 soils undergoing much wind erosion during the study period of 1972-1975 in four southwestern states and from comparison areas were determined. The delta/sup 18/O for quartz from eight Texas (TX) and Arizona (AZ) soils range from 13.0 to 15.9 /sup 0///sub 00/. The quartz of the sands and silts coarser than 20 ..mu..m from three of the soils had delta/sup 18/O values ranging from 13.1 to 15.1 /sup 0///sub 00/, characteristic of an ultimate igneous-metamorphic origin. The delta/sup 18/O values increase greatly with decreasing particle size of quartz from three soils ranging from loamy fine sand to loam to clay in texture. The delta/sup 18/O of the 1-10 ..mu..m quartz fraction (aerosol size) ranged from 19.2 to 20.2 /sup 0///sub 00/ (19.55 +- 0.28 /sup 0///sub 00/; +- sigma) for the thirteen soils most affected by dust storms. The oxygen isotopic ratios of 1-10 ..mu..m quartz from three Hawaiian soils and two sediments from Lake Waiau occurring at 3,970 m altitude on the Mauna Kea summit on the Island of Hawaii give a delta/sup 18/O mean of 18.3 +- 0.2 /sup 0///sub 00/.

  17. Isotopic compositions of boron in sediments and their implications

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Yingkai, X.

    The abundance and isotopic compositions of boron in sediments from the salt lakes of Qaidam Basin, China have been determined by thermal ionization mass spectrometry of cesium borate. The results show large variations in the isotopic compositions...

  18. CHLORINE ABUNDANCES IN COOL STARS

    Energy Technology Data Exchange (ETDEWEB)

    Maas, Z. G.; Pilachowski, C. A. [Indiana University Bloomington, Astronomy Department, Swain West 319, 727 East Third Street, Bloomington, IN 47405-7105 (United States); Hinkle, K., E-mail: zmaas@indiana.edu, E-mail: cpilacho@indiana.edu, E-mail: hinkle@noao.edu [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States)

    2016-12-01

    Chlorine abundances are reported in 15 evolved giants and 1 M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H{sup 35}Cl at 3.69851 μ m. The high-resolution L -band spectra were observed using the Phoenix infrared spectrometer on the Kitt Peak Mayall 4 m telescope. The average [{sup 35}Cl/Fe] abundance in stars with −0.72 < [Fe/H] < 0.20 is [{sup 35}Cl/Fe] = (−0.10 ± 0.15) dex. The mean difference between the [{sup 35}Cl/Fe] ratios measured in our stars and chemical evolution model values is (0.16 ± 0.15) dex. The [{sup 35}Cl/Ca] ratio has an offset of ∼0.35 dex above model predictions, suggesting that chemical evolution models are underproducing Cl at the high metallicity range. Abundances of C, N, O, Si, and Ca were also measured in our spectral region and are consistent with F and G dwarfs. The Cl versus O abundances from our sample match Cl abundances measured in planetary nebula and H ii regions. In one star where both H{sup 35}Cl and H{sup 37}Cl could be measured, a {sup 35}Cl/{sup 37}Cl isotope ratio of 2.2 ± 0.4 was found, consistent with values found in the Galactic ISM and predicted chemical evolution models.

  19. Relative abundance of deformed wing virus, Varroa destructor virus 1, and their recombinants in honey bees (Apis mellifera) assessed by kmer analysis of public RNA-Seq data

    Science.gov (United States)

    Cornman, Robert S.

    2017-01-01

    Deformed wing virus (DWV) is a major pathogen of concern to apiculture, and recent reports have indicated the local predominance and potential virulence of recombinants between DWV and a related virus, Varroa destructor virus 1 (VDV). However, little is known about the frequency and titer of VDV and recombinants relative to DWV generally. In this study, I assessed the relative occurrence and titer of DWV and VDV in public RNA-seq accessions of honey bee using a rapid, kmer-based approach. Three recombinant types were detectable graphically and corroborated by de novo assembly. Recombination breakpoints did not disrupt the capsid-encoding region, consistent with previous reports, and both VDV- and DWV-derived capsids were observed in recombinant backgrounds. High abundance of VDV kmers was largely restricted to recombinant forms. Non-metric multidimensional scaling identified genotypic clusters among DWV isolates, which was corroborated by read mapping and consensus generation. The recently described DWV-C lineage was not detected in the searched accessions. The data further highlight the utility of high-throughput sequencing to monitor viral polymorphisms and statistically test biological predictors of titer, and point to the need for consistent methodologies and sampling schemes.

  20. Examining Basin-Scale Water and Climate Relations across the Pampa del Tamarugal, Atacama Desert through Spatial Analysis of Hydrogen, Carbon and Oxygen Isotopes in Tree Rings

    Science.gov (United States)

    Olson, E. J.; Dodd, J. P.; Rivera, M. A.

    2016-12-01

    Arid regions are extremely sensitive to variations hydroclimate. However, our understanding of past hydroclimate variations in these regions is often limited by a paucity of spatially resolved proxy data. The Atacama Desert of northern Chile is one of the driest regions on Earth, and hydroclimatic processes in the Atacama Desert may be a useful proxy for understanding the implications of expanding global aridity. In order to assess the ability of tree-ring isotope studies to record changes in hydrology and terrestrial climate in the Atacama Desert, oxygen (δ18O), carbon (δ13C) and hydrogen (δ2H) isotope values in tree rings of Prosopis tamarugo are analyzed for the modern period (1954-2014) when anthropogenic change to regional groundwater levels have been most notable. Samples of wood cellulose were collected throughout the Pampa del Tamarugal basin from 14 individuals and used to create an interpolated surface of isotope variations. The isotope data were then compared to groundwater depth from well monitoring data provided by the Dirección de General de Agua of Chile. There is a significant correlation between groundwater level and isotope values with best agreement occurring during the past two decades for δ18O (r = 0.58), δ13C (r = 0.55), and δ2H (r = 0.66) values. This spatial correlation analysis reveals that tree ring a-cellulose isotope values are a suitable proxy for reconstructing groundwater depth in the Pampa del Tamarugal Basin. A stepwise multiregression analysis between δ18O values of cellulose and several other environmental variables including groundwater level, relative humidity, and temperature suggest that groundwater depth is the dominate control of variation in the modern δ18O tree ring record. The response of tree cellulose to the hydroclimate in this region suggests that tree ring isotope variations may be used to reconstruct past hydroclimate conditions in arid regions throughout the globe.

  1. Spatial Mapping of Protein Abundances in the Mouse Brain by Voxelation Integrated with High-Throughput Liquid Chromatography ? Mass Spectrometry

    International Nuclear Information System (INIS)

    Petyuk, Vladislav A.; Qian, Weijun; Chin, Mark H.; Wang, Haixing H.; Livesay, Eric A.; Monroe, Matthew E.; Adkins, Joshua N.; Jaitly, Navdeep; Anderson, David J.; Camp, David G.; Smith, Desmond J.; Smith, Richard D.

    2007-01-01

    Temporally and spatially resolved mapping of protein abundance patterns within the mammalian brain is of significant interest for understanding brain function and molecular etiologies of neurodegenerative diseases; however, such imaging efforts have been greatly challenged by complexity of the proteome, throughput and sensitivity of applied analytical methodologies, and accurate quantitation of protein abundances across the brain. Here, we describe a methodology for comprehensive spatial proteome mapping that addresses these challenges by employing voxelation integrated with automated microscale sample processing, high-throughput LC system coupled with high resolution Fourier transform ion cyclotron mass spectrometer and a ''universal'' stable isotope labeled reference sample approach for robust quantitation. We applied this methodology as a proof-of-concept trial for the analysis of protein distribution within a single coronal slice of a C57BL/6J mouse brain. For relative quantitation of the protein abundances across the slice, an 18O-isotopically labeled reference sample, derived from a whole control coronal slice from another mouse, was spiked into each voxel sample and stable isotopic intensity ratios were used to obtain measures of relative protein abundances. In total, we generated maps of protein abundance patterns for 1,028 proteins. The significant agreement of the protein distributions with previously reported data supports the validity of this methodology, which opens new opportunities for studying the spatial brain proteome and its dynamics during the course of disease progression and other important biological and associated health aspects in a discovery-driven fashion

  2. Morphological variability, spatial distribution and abundance of Helicostomella species (Ciliophora: Tintinnina in relation to environmental factors (Argentine shelf; 40-55°S

    Directory of Open Access Journals (Sweden)

    Luciana F. Santoferrara

    2009-12-01

    Full Text Available For the first time a taxonomic and ecological study of species belonging to Helicostomella was performed over a mesoscale spatial distribution by examining ca. 3000 loricae collected in Argentine shelf waters during the austral autumn. Microscopic and statistical analysis revealed that the general shape and the oral diameter remained practically constant in the whole area surveyed, despite a continuous length fluctuation of ca. 300 µm, which includes the entire range present in eight previously reported species. Consequently, we consider that the genus may be represented only by H. subulata, whose strong fluctuations in length (mostly attributed to an increase in the collar length, density and biomass seem to respond to temperature, food availability and front-related processes. In Buenos Aires coastal waters associated with a quasi permanent estuarine front (40-40.5°S, mixed conditions would favour moderate abundances of long loricae, whereas in northern (42.5-45.5°S and southern (46-54.5°S Patagonian waters, high (103 ind. L-1 and low (< 5 ind. L-1 densities of short loricae seem to be a consequence of stratification and encystment, respectively. The non-occurrence of the species at 41-42°S, together with a three-fold reduction in length-related parameters between specimens from Buenos Aires and Patagonian waters, suggests a disjunct distribution.

  3. Process for isotope separation

    International Nuclear Information System (INIS)

    Emile, B.F.M.

    1983-11-01

    A process is claimed for isotopic separation applied to isotopes of elements that can be placed in at least a physicochemical form in which the isotopic atoms or the molecules containing these atoms can be easily displaced and for which there are selective radiations preferentially absorbed by the isotopes of a certain type or by the molecules containing them, said absorption substantially increasing the probability of ionization of said atoms or molecules relative to the atoms or molecules that did not absorb the radiation. The process consists of placing the isotopic mixture in such a form, subjecting it in a separation zone to selective radiations and to an electrical field that produces migration of positive ions toward the negative electrodes and negative ions toward the positive electrodes, and withdrawing from certain such zones the fractions thus enriched in certain isotopes

  4. Spectroscopic abundance analyses of the 3He stars HD 185330 and 3 Cen A

    Science.gov (United States)

    Sadakane, Kozo; Nishimura, Masayoshi

    2018-04-01

    Abundances of 21 elements in two 3He stars, HD 185330 and 3 Cen A, have been analysed relative to the well-studied sharp-lined B3 V star ι Her. Six elements (P, Ti, Mn, Fe, Ni, and Br) are over-abundant in these two peculiar stars, while six elements (C, O, Mg, Al, S, and Cl) are under-abundant. Absorption lines of the two rarely observed heavy elements Br II and Kr II are detected in both stars and these elements are both over-abundant. The centroid wavelengths of the Ca II infrared triplet lines in these stars are redshifted relative to those lines in ι Her and the presence of heavy isotopes of Ca (mass number 44-46) in these two stars is confirmed. In spite of these similarities, there are several remarkable differences in abundance pattern between these two stars. N is under-abundant in HD 185330, as in many Hg-Mn stars, while it is significantly over-abundant in 3 Cen A. P and Ga are both over-abundant in 3 Cen A, while only P is over-abundant and no trace of absorption line of Ga II can be found in HD 185330. Large over-abundances of Kr and Xe are found in both stars, while the abundance ratio Kr/Xe is significantly different between them (-1.4 dex in HD 185330 and +1.2 dex in 3 Cen A). Some physical explanations are needed to account for these qualitative differences.

  5. Stable Isotope Evidence for a Complex Fluid Evolution of the Northwestern British Columbia Coast Ranges Related to Terrane Accretion

    Science.gov (United States)

    Moertle, J.; Holk, G. J.

    2015-12-01

    Stable isotope geochemistry reveals a complex fluid evolution for the Western Metamorphic Belt (WMB), Coast Ranges Batholith (CRB), Central Gneiss Complex (CGC) and Coast Ranges Megalineament (CRM). These fluids are a product of a complex tectonic history related to terrane accretion that includes oblique convergence, metamorphism, magmatism, and orogenic collapse. From W-to-E, these fluid systems are as follows. High-pressure greenschist-to-amphibolite facies metasedimentary rocks of the WMB record variable mineral δD (-61 to -104‰) and δ18O (e.g., quartz +9.6 to +13.4‰) values with multiple minerals in apparent isotopic equilibrium (T ~ 450-550°C) suggest a low W/R system dominated by metamorphic fluids. Variable and non-equilibrium δD (-53 to -143‰) and δ18O (e.g., biotite +2.3 to +5.3‰) values from diorites of the Quottoon pluton affected by the ductile CRM suggest a complex evolution that involved both metamorphic and meteoric-hydrothermal fluids in this dextral shear zone; these results differ from those 300 km along strike to the north that documented only metamorphic fluids in the CRM (Goldfarb et al., 1988). Our data and those of Magaritz and Taylor (1976) from granulite facies metasediments of the CGC and plutons of the western CRB reveal homogeneous δD values (-62 to -78‰) and a restricted range of δ18O values (e.g., quartz +8.5 to +11.5‰) with all minerals in equilibrium at T > 570°C indicate a system dominated by magmatic fluids. Calculated whole-rock δ18O values (~ +7‰) for the Quottoon pluton and CRB intrusive rocks suggest a mantle origin for these magmas. Reinterpretation of very low δD (< -150‰) and quartz-feldspar δ18O pairs that display extreme disequilibrium (feldspar δ18O values as low as -5‰) from the Ponder pluton, eastern CRB, and Hazelton Group point reveals that the major meteoric-hydrothermal system that affected these rocks was related to Eocene detachment faulting along the Shames Lake fault system, a

  6. The theory and uses of natural uranium isotopic variations in hydrology

    International Nuclear Information System (INIS)

    Osmond, J.K.; Cowart, J.B.

    1976-01-01

    The dissolved concentration of uranium and the relative abundance of two uranium isotopes, 234 U and 238 U, vary over a wide range of values in natural waters. The concentration is controlled mainly by the redox potential of the environment and by CO 2 . The mechanism of isotope fractionation is thought to be entrainment of 234 U in the aqueous phase either by selective leaching of the solid phase or by direct recoil of the daughter nuclide. Ion exchange techniques and alpha-spectrometry permit the measurement of uranium at concentrations as low as pp 10 11 and the isotopic ratio to a few per cent. In oxidizing conditions the uranium isotopes behave in a chemically stable conservative manner such that separate groundwater sources may have identifiably different characteristics and mixing volume calculations may be made. Other potential use of these isotopes include radiometric dating, tracing of hydrologic systems, ore prospecting and earthquake prediction. (author)

  7. Quantifying nitrous oxide production pathways in wastewater treatment systems using isotope technology - A critical review.

    Science.gov (United States)

    Duan, Haoran; Ye, Liu; Erler, Dirk; Ni, Bing-Jie; Yuan, Zhiguo

    2017-10-01

    Nitrous oxide (N 2 O) is an important greenhouse gas and an ozone-depleting substance which can be emitted from wastewater treatment systems (WWTS) causing significant environmental impacts. Understanding the N 2 O production pathways and their contribution to total emissions is the key to effective mitigation. Isotope technology is a promising method that has been applied to WWTS for quantifying the N 2 O production pathways. Within the scope of WWTS, this article reviews the current status of different isotope approaches, including both natural abundance and labelled isotope approaches, to N 2 O production pathways quantification. It identifies the limitations and potential problems with these approaches, as well as improvement opportunities. We conclude that, while the capabilities of isotope technology have been largely recognized, the quantification of N 2 O production pathways with isotope technology in WWTS require further improvement, particularly in relation to its accuracy and reliability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Pb isotopes as tracers of mining-related Pb in lichens, seaweed and mussels near a former Pb-Zn mine in West Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Sondergaard, Jens, E-mail: jens@dmu.d [Department of Arctic Environment, National Environmental Research Institute, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Asmund, Gert; Johansen, Poul [Department of Arctic Environment, National Environmental Research Institute, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Elberling, Bo [Institute of Geography and Geology, University of Copenhagen, Oster Voldgade 10, DK-1350 Copenhagen K (Denmark); University Centre in Svalbard, NO-9171 Longyearbyen (Norway)

    2010-05-15

    Identification of mining-related contaminants is important in order to assess the spreading of contaminants from mining as well as for site remediation purposes. This study focuses on lead (Pb) contamination in biota near the abandoned 'Black Angel Mine' in West Greenland in the period 1988-2008. Stable Pb isotope ratios and total Pb concentrations were determined in lichens, seaweed and mussels as well as in marine sediments. The results show that natural background Pb ({sup 207}Pb/{sup 206}Pb: 0.704-0.767) and Pb originating from the mine ore ({sup 207}Pb/{sup 206}Pb: 0.955) have distinct isotopic fingerprints. Total Pb in lichens, seaweed, and mussels was measured at values up to 633, 19 and 1536 mg kg{sup -1} dry weight, respectively, and is shown to be a mixture of natural Pb and ore-Pb. This enables quantification of mining-related Pb and shows that application of Pb isotope data is a valuable tool for monitoring mining pollution. - Lead isotopes can be used to monitor uptake of mining-related lead in lichens, seaweed and mussels.

  9. Geochemistry of the stable isotopes of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Douthitt, C B [California Inst. of Tech., Pasadena (USA). Div. of Geological and Planetary Sciences

    1982-08-01

    One hundred thirty two new measurements of the relative abundances of the stable isotopes of silicon in terrestrial materials are presented. The total variation of delta/sup 30/Si found is 6.2 parts per thousand, centered on the mean of terrestrial mafic and ultramafic igneous rocks, delta/sup 30/Si = -0.4 parts per thousand. Igneous rocks show limited variation; coexisting minerals exhibit small, systematic silicon isotopic fractionations that are roughly 1/3 the magnitude of concomitant oxygen isotopic fractionations at 1150/sup 0/C. In both igneous minerals and rocks, delta/sup 30/Si shows a positive correlation with silicon content, as does delta/sup 18/O. Opal from both sponge spicules and sinters is light, with delta/sup 30/Si = -2.3 and -1.4 parts per thousand respectively. Large delta/sup 30/Si values of both positive and negative sign are reported for the first time from clay minerals, opaline phytoliths, and authigenic quartz. All highly fractionated samples were precipitated from solution at low temperatures; however, aqueous silicon is not measurably fractionated relative to quartz at equilibrium. A kinetic isotope fractionation of approximately 3.5 parts per thousand is postulated to occur during the low temperature precipitation of opal and, possibly, poorly ordered phyllosilicates, with the silicate phase being enriched in /sup 28/Si. This fractionation, coupled with a Rayleigh precipitation model, is capable of explaining most non-magmatic delta/sup 30/Si variations.

  10. Fission cross sections of some thorium, uranium, neptunium and plutonium isotopes relative to /sup 235/U

    Energy Technology Data Exchange (ETDEWEB)

    Meadows, J W

    1983-10-01

    Earlier results from the measurements, at this Laboratory, of the fission cross sections of /sup 230/Th, /sup 232/Th, /sup 233/U, /sup 234/U, /sup 236/U, /sup 238/U, /sup 237/Np, /sup 239/Pu, /sup 240/Pu, and /sup 242/Pu relative to /sup 235/U are reviewed with revisions to include changes in data processing procedures, alpha half lives and thermal fission cross sections. Some new data have also been included. The current experimental methods and procedures and the sample assay methods are described in detail and the sources of error are presented in a systematic manner. 38 references.

  11. Abundance, biomass and caloric content of Chukchi Sea bivalves and association with Pacific walrus (Odobenus rosmarus divergens) relative density and distribution in the northeastern Chukchi Sea

    Science.gov (United States)

    Young, Jordann K.; Black, Bryan A.; Clarke, Janet T.; Schonberg, Susan V.; Dunton, Kenneth H.

    2017-10-01

    The northeastern Chukchi Sea is a shallow subarctic shelf ecosystem that supports a substantial benthic infaunal community of which bivalves are a major component. We assessed the patterns in population abundance, biomass, and caloric content of ten dominant bivalve taxa in relation to the distribution of the upper trophic level consumer Pacific walrus (Odobenus rosmarus divergens). Bivalves were collected over four cruises in the northeastern Chukchi Sea (2009, 2010, 2012, 2013). Our samples were largely dominated by calorie-dense, deposit-feeding species, including Macoma spp., Ennucula tenuis, Nuculana spp. and Yoldia spp. Weight-frequency distributions were strongly right-skewed for most taxa, though some showed evidence of a bimodal distribution. Caloric densities as measured through bomb calorimetry significantly differed among taxa (ANOVA F = 32.57, df = 9, p-valueanimal wet weight was found to be a reliable predictor of whole animal caloric content. Bivalve populations and peak caloric densities were centered on and to the southeast of Hanna Shoal, which coincided with peak Pacific walrus relative density (walruses per km surveyed) from July through October. Significant differences in mean caloric values were found between areas with and without walruses present (student's t-test, t=-2.9088, df = 252.24, p-value = 0.003952), as well as between areas with low and high walrus relative densities in the pooled annual dataset and in each individual month except October (ANOVA, p-value<0.05). The high-calorie deposit feeders that dominate these bivalve communities preferentially consume food sources, such as sea ice algae, that are likely to be affected by shifting sea ice dynamics. As such, continued warming has the potential to alter bivalve communities in the northeastern Chukchi Sea, which may have profound implications for upper trophic levels.

  12. Nutritional efficiency of alpha-ketoisocaproate relative to leucine, assessed isotopically

    International Nuclear Information System (INIS)

    Kang, C.W.; Walser, M.

    1985-01-01

    The efficiency of alpha-ketoisocaproate as a dietary substitute for leucine was assessed in rats by two techniques: first, the minimal dose of alpha-ketoisocaproate required, as a supplement to a leucine-free diet, to achieve a growth rate as great as animals receiving leucine was found to be between 2.2 and 4.4 times larger. Therefore the nutritional efficiency of alpha-ketoisocaproate lies between 0.23 and 0.46. Second, alpha-[1- 14 C]-ketoisocaproate and [ 3 H]leucine were administered orally and the ratio of 14 C/ 3 H incorporated into the leucine of whole-body protein and fibrin was measured. This ratio, divided by the ratio 14 C/ 3 H injected, was the same in fibrin as in whole-body protein and averaged 0.39. Thus both techniques yield the same value, within the error of measurement, for the relative nutritional efficiency of alpha-ketoisocaproate. The authors also found that alpha-ketoisocaproate feeding at varying dosage did not alter this ratio in whole-body protein, suggesting that neither wide variations in growth rate nor exposure for 10 days to alpha-ketoisocaproate alters the relative rates of utilization (or oxidation) of alpha-ketoisocaproate vs. leucine

  13. Nutritional efficiency of alpha-ketoisocaproate relative to leucine, assessed isotopically

    Energy Technology Data Exchange (ETDEWEB)

    Kang, C.W.; Walser, M.

    1985-10-01

    The efficiency of alpha-ketoisocaproate as a dietary substitute for leucine was assessed in rats by two techniques: first, the minimal dose of alpha-ketoisocaproate required, as a supplement to a leucine-free diet, to achieve a growth rate as great as animals receiving leucine was found to be between 2.2 and 4.4 times larger. Therefore the nutritional efficiency of alpha-ketoisocaproate lies between 0.23 and 0.46. Second, alpha-(1- UC)-ketoisocaproate and (TH)leucine were administered orally and the ratio of UC/TH incorporated into the leucine of whole-body protein and fibrin was measured. This ratio, divided by the ratio UC/TH injected, was the same in fibrin as in whole-body protein and averaged 0.39. Thus both techniques yield the same value, within the error of measurement, for the relative nutritional efficiency of alpha-ketoisocaproate. The authors also found that alpha-ketoisocaproate feeding at varying dosage did not alter this ratio in whole-body protein, suggesting that neither wide variations in growth rate nor exposure for 10 days to alpha-ketoisocaproate alters the relative rates of utilization (or oxidation) of alpha-ketoisocaproate vs. leucine.

  14. Relative abundance of 'Bacillus' spp., surfactant-associated bacterium present in a natural sea slick observed by satellite SAR imagery over the Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Kathryn Lynn Howe

    2018-01-01

    Full Text Available The damping of short gravity-capillary waves (Bragg waves due to surfactant accumulation under low wind speed conditions results in the formation of natural sea slicks. These slicks are detectable visually and in synthetic aperture radar satellite imagery. Surfactants are produced by natural life processes of many marine organisms, including bacteria, phytoplankton, seaweed, and zooplankton. In this work, samples were collected in the Gulf of Mexico during a research cruise on the R/V 'F.G. Walton Smith' to evaluate the relative abundance of 'Bacillus' spp., surfactant-associated bacteria, in the sea surface microlayer compared to the subsurface water at 0.2 m depth. A method to reduce potential contamination of microlayer samples during their collection on polycarbonate filters was implemented and advanced, including increasing the number of successive samples per location and changing sample storage procedures. By using DNA analysis (real-time polymerase chain reaction to target 'Bacillus' spp., we found that in the slick areas, these surfactant-associated bacteria tended to reside mostly in subsurface waters, lending support to the concept that the surfactants they may produce move to the surface where they accumulate under calm conditions and enrich the sea surface microlayer.

  15. Permafrost response to increasing Arctic shrub abundance depends on the relative influence of shrubs on local soil cooling versus large-scale climate warming

    International Nuclear Information System (INIS)

    Lawrence, David M; Swenson, Sean C

    2011-01-01

    Deciduous shrub abundance is increasing across the Arctic in response to climatic warming. In a recent field manipulation experiment in which shrubs were removed from a plot and compared to a control plot with shrubs, Blok et al (2010 Glob. Change Biol. 16 1296–305) found that shrubs protect the ground through shading, resulting in a ∼ 9% shallower active layer thickness (ALT) under shrubs compared to grassy-tundra, which led them to argue that continued Arctic shrub expansion could mitigate future permafrost thaw. We utilize the Community Land Model (CLM4) coupled to the Community Atmosphere Model (CAM4) to evaluate this hypothesis. CLM4 simulates shallower ALT (∼− 11 cm) under shrubs, consistent with the field manipulation study. However, in an idealized pan-Arctic + 20% shrub area experiment, atmospheric heating, driven mainly by surface albedo changes related to protrusion of shrub stems above the spring snowpack, leads to soil warming and deeper ALT (∼+ 10 cm). Therefore, if climate feedbacks are considered, shrub expansion may actually increase rather than decrease permafrost vulnerability. When we account for blowing-snow redistribution from grassy-tundra to shrubs, shifts in snowpack distribution in low versus high shrub area simulations counter the climate warming impact, resulting in a grid cell mean ALT that is unchanged. These results reinforce the need to consider vegetation dynamics and blowing-snow processes in the permafrost thaw model projections.

  16. Electrochemically controlled iron isotope fractionation

    Science.gov (United States)

    Black, Jay R.; Young, Edward D.; Kavner, Abby

    2010-02-01

    Variations in the stable isotope abundances of transition metals have been observed in the geologic record and trying to understand and reconstruct the physical/environmental conditions that produced these signatures is an area of active research. It is clear that changes in oxidation state lead to large fractionations of the stable isotopes of many transition metals such as iron, suggesting that transition metal stable isotope signatures could be used as a paleo-redox proxy. However, the factors contributing to these observed stable isotope variations are poorly understood. Here we investigate how the kinetics of iron redox electrochemistry generates isotope fractionation. Through a combination of electrodeposition experiments and modeling of electrochemical processes including mass-transport, we show that electron transfer reactions are the cause of a large isotope separation, while mass transport-limited supply of reactant to the electrode attenuates the observed isotopic fractionation. Furthermore, the stable isotope composition of electroplated transition metals can be tuned in the laboratory by controlling parameters such as solution chemistry, reaction overpotential, and solution convection. These methods are potentially useful for generating isotopically-marked metal surfaces for tracking and forensic purposes. In addition, our studies will help interpret stable isotope data in terms of identifying underlying electron transfer processes in laboratory and natural samples.

  17. Isotope heterogeneity of Pre-Holocene groundwater in Iceland

    DEFF Research Database (Denmark)

    Sveinbjörnsdóttir, Á.E.; Arnorsson, S.; Heinemeier, Jan

    2007-01-01

    In recent years, it has been shown that groundwater with a Pre-Holocene component is more common in the Icelandic bedrock than previously thought. Some of the Pre-Holocene water samples are more depleted in delta H-2 and delta O-18 than any mean annual precipitation in Iceland today due to the cold...... climate at that time. However, most often Pre-Holocene water components cannot be detected based on the water isotopes alone due to mixing with younger and isotopically heavier water. The Cl concentration in relation to the water isotopes in specific areas has proved to be a good indicator of a Pre......-Holocene component in the groundwater. The deuterium excess value may also help to identify water from a different climate regime, if no oxygen shift has occurred. The relative abundance of a Pre-Holocene water component of the Icelandic groundwater has led to the understanding that combined interpretation of water...

  18. Harmonization of health related environmental measurements using nuclear and isotopic techniques. Proceedings of an international symposium

    International Nuclear Information System (INIS)

    1997-01-01

    One of the particular strengths of nuclear methods is in analytical quality assurance, including the validation of analytical methods and the development of new analytical reference materials. These methodologies are therefore helping to harmonize the data produced not only by nuclear techniques themselves, but also by other non-nuclear methods of analysis. The aim of this symposium was to provide an international forum for discussion of these topics. Its programme covered a wide variety of applications of nuclear (and related) analytical techniques (mainly neutron activation analysis, energy dispersive X ray fluorescence, particle induced X ray emission and inductively coupled plasma-mass spectrometry) as used in the study of air particulates, solid waste products, sediments, food, water, human tissues, biomonitors and other kinds of environmental samples

  19. A paleomagnetic and stable isotope study of the pluton at Rio Hondo near Questa, New Mexico: Implications for CRM related to hydrothermal alteration

    International Nuclear Information System (INIS)

    Hagstrum, J.T.; Johnson, C.M.

    1986-01-01

    Paleomagnetic and rock magnetic data combined with stable isotope data from the middle Tertiary pluton along the Rio Hondo in northern New Mexico suggest that its magnetic remanence has both thermal (TRM) and high-temperature chemical (CRM) components. Oxygen isotope temperatures indicate that magnetite associated with the more rapidly cooled higher levels of the pluton, and with mafic inclusions and cogenetic rhyolitic dikes sampled at lower levels of exposure, ceased subsolidus recrystallization and isotopic exchange above its Curie temperature (580 0 C) in the presence of a magmatic fluid. Continued cooling imparted a TRM to these portions of the pluton. The more slowly cooled granodiorite at lower levels has quartz-magnetite isotopic temperatures that are below the Curie temperature of magnetite implying that its magnetization is high-temperature CRM. Sub-Curie isotopic temperatures for other granitic plutons in the western U.S.A. suggest that CRM may be commonly derived from subsolidus interactions between magnetite and magmatic fluids in plutonic rocks. A meteoric-hydrothermal system generated by the cooling Rio Hondo pluton, and not by younger adjacent intrusions, resulted in limited alteration along zones of high permeability near the southern margin of the Rio Hondo pluton, and in more prevasive alteration of the pluton to the north. The meteoric-hydrothermal alteration occurred at relatively high temperatures (>350 0 C) and, with the exception of local chloritization, caused little visible alteration of the rocks. The isotopic ratios indicate that little of the magnetite could have grown from or exchanged with a meteoric-hydrothermal fluid. (orig.)

  20. Paleomagnetic and stable isotope study of the pluton at Rio Hondo near Questa, New Mexico: Implications for CRM related to hydrothermal alteration

    Energy Technology Data Exchange (ETDEWEB)

    Hagstrum, J T; Johnson, C M

    1986-06-01

    Paleomagnetic and rock magnetic data combined with stable isotope data from the middle Tertiary pluton along the Rio Hondo in northern New Mexico suggest that its magnetic remanence has both thermal (TRM) and high-temperature chemical (CRM) components. Oxygen isotope temperatures indicate that magnetite associated with the more rapidly cooled higher levels of the pluton, and with mafic inclusions and cogenetic rhyolitic dikes sampled at lower levels of exposure, ceased subsolidus recrystallization and isotopic exchange above its Curie temperature (580/sup 0/C) in the presence of a magmatic fluid. Continued cooling imparted a TRM to these portions of the pluton. The more slowly cooled granodiorite at lower levels has quartz-magnetite isotopic temperatures that are below the Curie temperature of magnetite implying that its magnetization is high-temperature CRM. Sub-Curie isotopic temperatures for other granitic plutons in the western U.S.A. suggest that CRM may be commonly derived from subsolidus interactions between magnetite and magmatic fluids in plutonic rocks. A meteoric-hydrothermal system generated by the cooling Rio Hondo pluton, and not by younger adjacent intrusions, resulted in limited alteration along zones of high permeability near the southern margin of the Rio Hondo pluton, and in more prevasive alteration of the pluton to the north. The meteoric-hydrothermal alteration occurred at relatively high temperatures (>350/sup 0/C) and, with the exception of local chloritization, caused little visible alteration of the rocks. The isotopic ratios indicate that little of the magnetite could have grown from or exchanged with a meteoric-hydrothermal fluid.

  1. Effect of complexing reagents on the ionization constant of boric acid and its relation to isotopic exchange separation factor

    International Nuclear Information System (INIS)

    Sharma, B.K.; Subramanian, R.; Mathur, P.K.

    1991-01-01

    The effect of change in concentration of complexing reagents having two or more hydroxyl groups, viz., ethylene glycol, propylene glycol, dextrose and mannitol on the ionization constant of boric acid has been studied by pH-metric titration method. The effect of increase in ionization constant of boric acid on isotopic exchange separation factor for the separation of isotopes of boron by ion exchange chromatography has been studied by the batch method. (author). 9 refs

  2. Size-related and seasonal diet of the manila clam (Ruditapes philippinarum), as determined using dual stable isotopes

    Science.gov (United States)

    Suh, Yeon Jee; Shin, Kyung-Hoon

    2013-12-01

    Stable isotope ratios of lab-cultured Manila clams (Ruditapes philippinarum) and those from natural tidal flats of Seonjae Island in Korea were investigated in terms of their dietary uptake patterns in relation to body size and season. The smallest size group of wild Manila clams revealed significantly depleted δ15N based on the results of a one-way ANOVA. There was significant seasonal change in the proportional contribution of food sources, especially in winter, from benthic particulate organic matter (BPOM) to pelagic particulate organic matter (POM). Laboratory-cultured Manila clams showed growth rates of 6.02-37.75 mm/yr, and smaller-sized clams did not fully utilise the microalgal diets that were provided constantly. Instead, they derived most of their energy from detritus or dead microalgae that had settled on the bottom. Bigger clams, however, exhibited well-balanced source contributions, converting the microalgal diets into biomass. This demonstrates intra-specific differences in the growth rates and preferred diet uptakes of Manila clams, even under similar environmental conditions.

  3. Studies of osteoporosis in urban residents of Sao Paulo, Brazil, using isotope related techniques

    International Nuclear Information System (INIS)

    Borelli, Aurelio

    2002-01-01

    Poor bone mass is a major public health problem of worldwide concern. Obviously the main reason for this concern is the fact that the decreasing bone mass is directly related to bone fragility, osteoporosis and increased incidence of fractures affecting mainly elder people. The problems originated from the bone fractures involved areas as economy, social and scientific. Such is the importance of this problem that the Scientific Advisory Committee of the World Health Organization selected osteoporosis as one of the four priority research areas being developed by the Program for Research on Aging. The project on osteoporosis is a crossnational study which will try to explain the differences in hip fractures in countries around the world disclosing the risk and protective factors which will help developing etiologic hypotheses and planning specific preventive interventions. One of the primary objectives is to determine the age range over which peak bone mass (BMD) is maintained which is a valuable guide for plans of osteoporosis prevention. This project is aimed at defining the peak bone mass as well as the period it lasts before the non-nal decrease with aging

  4. Studies of osteoporosis in urban residents of Sao Paulo, Brazil, using isotope related techniques

    International Nuclear Information System (INIS)

    Borelli, A.

    1998-01-01

    Osteoporosis is presently a major problem scientific as well as economic all over the world. For this reason this disease has been studied quite intensely involving not only researchers but also densitometer makers and medicine manufacturers. Many etiologies have been described relating factors which could interfere either in bone formation or bone reabsorption or both. As bone loss along the life is a normal event it is quite understandable that the amount of remaining bone will depend on the amount gained during bone formation. For this reason it is quite important to know the peak of bone mass and the factors that would interfere in the amount of bone formed. It is also very important to define for a certain population its peak of bone mass which would be a valuable guide for future plans of osteoporosis prevention. This project is aimed at defining the peak of bone mass in an urban population which was chosen randomly taken into account the fact that there is a great miscegenation in S.Paulo

  5. Distribuição e abundância relativa de bagres marinhos (Siluriformes, Ariidae na Baía de Sepetiba, Rio de Janeiro Distribution and relative abundance of the marine catfish (Siluriformes, Ariidae in Sepetiba Bay, Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Márcia Cristina Costa de Azevedo

    1998-12-01

    Full Text Available Marine catfish (Ariidae are abundant resources in otter trawl fisheries carried out at Sepetiba Bay, Rio de Janeiro (Lat. 22º54, 23º04'S; Long. 43º34 44º10'W. Relative abundance and distribution were assessed, based in 158 fishing sampling at seven sites in the Bay, between July-1993 e June-1996. Five species were recorded in the following abundance rank order: Genidens genidens (Valenciennes, 1839, Caihorops spixii (Agassiz,1829, Sciadeichthys lunisculis (Valenciennes, 1840, Nelunia barba (Lacépède, 1803, and Bagre marinus (Mitchill, 1814, the latter have been caught in only two samples. Marine catfish showed higher abundance in the inner Bay, with indication of spatial segregation. G genidens was abundant in ali sites of lhe inner Bay, C. spixii e N. barba, near to rivers mouths, andS lunisculis, being widespread in ali studied area. Sazonality was not evident, with few exceplions in some of the three annual cycles; G. genidens and S. luniscutis were more abundant in biomass in summer 1994/95 (G. genidens and 1993/94 (S. luniscutis. G. genidens e N. barba show higher abundance (CPUE and biomass between July-93 and June-95 and C. spixii e S. luniscutis between July-95 and June-96. Total association index indicates a overall positive association among ali species, with. higher Jaccard and Sorensen similarities coefficient for the pairs C. spixii/G. genidens, G. genidens/S. luniscutis, e C. spixii/S. luniscutis. Pearson linear correlation and Sperman rank indicate that G. genidens and N. barba are inversely correlated to C. spixii and S. luniscutis. Spatial segregation strategy may be explaining the coexistence of the marine catfish at Sepetiba Bay.

  6. Is Ammonification Rate in Marine Sediment Related to Plankton Composition and Abundance? A Time-series Study in Villefranche Bay (NW Mediterranean)

    Science.gov (United States)

    Fernex, François E.; Braconnot, Jean-Claude; Dallot, Serge; Boisson, Michel

    1996-09-01

    Observations were made near Cap Ferrat (Station B, about 80 m in water depth) France, in the water column and in the sediment, in order to evaluate to what extent variations in the ammonia and nitrate concentrations of the sediments are related to plankton population abundance and composition. Nitrate, nitrite, ammonia and chlorophyll awere measured several times during 1987 to 1989, at two depths (1 and 40 m). Copepods and salps in the upper 75 m of the water column were counted several times a week from 1987 to 1990. Ammonia and nitrate concentrations and ammonification rate were determined in the underlying sediments. During Spring 1987, phytoplankton biomass showed a maximum at the end of March; copepod populations increased regularly till the end of April, and salps increased from this time to the end of May. These populations were not so well developed during Spring 1988 and 1989. During the blooms, salp were mainly represented by Thalia democratica. The biomass of phytoplankton and zooplankton was low in summer. The sequence suggests that the copepod decline was related to reduced food levels after the phytoplankton decline. Salp population growth was not at the expense of phytoplankton and it can be assumed that the salp fed on other material. In 1987 and 1988, maximum organic nitrogen concentration in the bottom sediment and maximum ammonification rate directly followed the salp spring bloom. In 1987, the highest ammonification rate measured in the surficial sediment (0-2 cm) reached 0·05 μ M cm 3day -1(in June). In 1990, the rate exceeded 0·1 μM cm -3 day -1during an important salp bloom. Therefore, it seems that the sinking of salp fecal pellets plays an important part in the transfer of organic matter to the bottom, and microbial activity in the surficial sediment leads to mineralization of a great part of the organic nitrogen quickly after its deposition.

  7. Oxygen abundances in halo stars

    Science.gov (United States)

    Bessell, Michael S.; Sutherland, Ralph S.; Ruan, Kui

    1991-12-01

    The present study determines the oxygen abundance for a sample of metal-poor G dwarfs by analysis of OH lines between 3080 and 3200 A and the permitted high-excitation far-red O I triple. The oxygen abundances determined from the low-excitation OH lines are up to 0.55 dex lower than those measured from the high-excitation O I lines. The abundances for the far-red O I triplet lines agree with those rederived from Abia and Rebolo (1989), and the abundances from the OH lines in dwarfs and giants are in agreement with the rederived O abundances of Barbuy (1988) and others from the forbidden resonance O I line. Because the chi = 0.1.7 eV OH lines are formed in the same layers as the majority of Fe, Ti, and other neutral metal lines used for abundance analyses, it is argued that the OH lines and the forbidden O I line yield the true oxygen abundances relative to the metals.

  8. Studies of osteoporosis in South Africa using isotope-related and other techniques

    International Nuclear Information System (INIS)

    Wynchank, S.

    1998-01-01

    This report is limited by its being an interim account of the research and is of necessity incomplete. Amongst the present data, there are insufficient results obtained for African subjects and for the extreme age ranges. These lacunae are expected to remain temporary set backs. All the measurements were made on the patients' left sides. This was chosen to coincide with the non-dominant femoral region. One trend is clear for all groups of subjects, where there are sufficient statistics. There is the expected fall in BMD beyond the age of menopause. Although there are severe statistical constraints on data to date from African subjects, their BMD is probably not lower than that of the other groups. Since their social circumstances are generally unsatisfactory, this is at first sight surprising and clearly requires further investigation. For persons of the other two groups the statistics are better. There is little discernible difference in the BMD values of the two groups at all ages. Important questions raised in this work include the following. What are the relative contributions of genetic and dietary influences to differences in BMD? This can only be answered by more BMD studies, especially on Africans, and preferably accompanied by investigations of dietary and other relevant habits It is likely that the African diet differs from that of the other groups. But there is evidence to show that such differences are becoming eroded. (Such evidence arises both from dietary surveys and from incidence of the burden of life-style associated diseases.) Future work will include trace element determinations on autopsy samples

  9. Isotope shifting capacity of rock

    International Nuclear Information System (INIS)

    Blattner, P.; Department of Scientific and Industrial Research, Lower Hutt

    1980-01-01

    Any oxygen isotope shifted rock volume exactly defines a past throughput of water. An expression is derived that relates the throughput of an open system to the isotope shift of reservoir rock and present-day output. The small isotope shift of Ngawha reservoir rock and the small, high delta oxygen-18 output are best accounted for by a magmatic water source

  10. 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

  11. Multiple marker abundance profiling

    DEFF Research Database (Denmark)

    Hooper, Cornelia M.; Stevens, Tim J.; Saukkonen, Anna

    2017-01-01

    proteins and the scoring accuracy of lower-abundance proteins in Arabidopsis. NPAS was combined with subcellular protein localization data, facilitating quantitative estimations of organelle abundance during routine experimental procedures. A suite of targeted proteomics markers for subcellular compartment...

  12. Isotopic composition of precipitation in the Mediterranean Basin in relation to air circulation patterns and climate. Final report of a coordinated research project 2000-2004

    International Nuclear Information System (INIS)

    2005-10-01

    The IAEA has operated the Global Network of Isotopes in Precipitation (GNIP) since 1961. There has been an increased need for GNIP data following the recognition of the role of precipitation stable isotopes in better simulating the hydrologic cycle in climate models. The isotopic composition of precipitation is closely related to rain formation conditions, i.e. with the temperature of formation, the origin of air masses, and the degree and mechanism of rainout. Over the last twenty years, use of GNIP data in climate model has indicated a need for a much more refined, process-based understanding of isotope variations in the hydrological cycle. This coordinated research project (CRP) was initiated with the aim of collecting new data on higher spatial density and temporal frequency to improve our knowledge of environmental isotope variations in atmospheric waters. The Mediterranean region was chosen for this study so that climatic and meteorological conditions, which govern the rain formation process, and their variations along east-west and north-south directions, could be investigated. In addition, the first steps of the hydrological cycle, that is evaporation from seawater and condensation of atmospheric vapour could also be studied. The IAEA invited scientists from institutes in Mediterranean countries who have already been involved in studies related to the isotopic composition of precipitation to take part in this CRP, which was initiated in 2000. This publication is a summary of the results achieved in the CRP. The overall achievements are presented as the executive summary, and the detailed findings are presented in each contribution. These results were presented in the final research coordination meeting, held in Vienna from 15 to 19 March 2004. The results of this CRP are relevant to the Member State scientists conducting hydrological research. In addition, the results would contribute to the IAEA programme on water resources, in particular to its activities

  13. Isotopic clusters

    International Nuclear Information System (INIS)

    Geraedts, J.M.P.

    1983-01-01

    Spectra of isotopically mixed clusters (dimers of SF 6 ) are calculated as well as transition frequencies. The result leads to speculations about the suitability of the laser-cluster fragmentation process for isotope separation. (Auth.)

  14. Magellanic Clouds Cepheids: Thorium Abundances

    Directory of Open Access Journals (Sweden)

    Yeuncheol Jeong

    2018-03-01

    Full Text Available The analysis of the high-resolution spectra of 31 Magellanic Clouds Cepheid variables enabled the identification of thorium lines. The abundances of thorium were found with spectrum synthesis method. The calculated thorium abundances exhibit correlations with the abundances of other chemical elements and atmospheric parameters of the program stars. These correlations are similar for both Clouds. The correlations of iron abundances of thorium, europium, neodymium, and yttrium relative to the pulsational periods are different in the Large Magellanic Cloud (LMC and the Small Magellanic Cloud (SMC, namely the correlations are negative for LMC and positive or close to zero for SMC. One of the possible explanations can be the higher activity of nucleosynthesis in SMC with respect to LMC in the recent several hundred million years.

  15. Isotope separation

    International Nuclear Information System (INIS)

    Eerkens, J.W.

    1979-01-01

    A method of isotope separation is described which involves the use of a laser photon beam to selectively induce energy level transitions of an isotope molecule containing the isotope to be separated. The use of the technique for 235 U enrichment is demonstrated. (UK)

  16. Environmental isotope hydrology

    International Nuclear Information System (INIS)

    1973-01-01

    Environmental isotope hydrology is a relatively new field of investigation based on isotopic variations observed in natural waters. These isotopic characteristics have been established over a broad space and time scale. They cannot be controlled by man, but can be observed and interpreted to gain valuable regional information on the origin, turnover and transit time of water in the system which often cannot be obtained by other techniques. The cost of such investigations is usually relatively small in comparison with the cost of classical hydrological studies. The main environmental isotopes of hydrological interest are the stable isotopes deuterium (hydrogen-2), carbon-13, oxygen-18, and the radioactive isotopes tritium (hydrogen-3) and carbon-14. Isotopes of hydrogen and oxygen are ideal geochemical tracers of water because their concentrations are usually not subject to change by interaction with the aquifer material. On the other hand, carbon compounds in groundwater may interact with the aquifer material, complicating the interpretation of carbon-14 data. A few other environmental isotopes such as 32 Si and 238 U/ 234 U have been proposed recently for hydrological purposes but their use has been quite limited until now and they will not be discussed here. (author)

  17. LIFE CYCLE, DISTRIBUTION AND ABUNDANCE OF CARCINONEMERTES EPIALTI, A NEMERTEAN EGG PREDATOR OF THE SHORE CRAB, HEMIGRAPSUS OREGONENSIS, IN RELATION TO HOST SIZE, REPRODUCTION AND MOLT CYCLE.

    Science.gov (United States)

    Kuris, Armand M

    1978-02-01

    1. The geographic range of Carcinonemertes epialti has been greatly extended. The worms are found from Bahia San Quintin, Baja California, Mexico, to Page's Lagoon, Vancouver Island, British Columbia, Canada. 2. New host records for C. epialti include H. oregonensis, and H. nudus. It is rare on its type host Pugettia producta. Specimens of Carcinonemertes of uncertain affinities are also found on Cancer antennarius, C. anthonyi and C. productus. 3. Carcinonemertes epialti adults are egg predators on ovigerous hosts. Growth, demography and abundance are described in relation to the embryogenic stage of the host brood at Bodega Harbor, California. 4. Nonfeeding juveniles are ensheathed on individuals of both host sexes over 8.0 mm carapace width. 5. Transmission experiments show that contact transfer of juvenile nemerteans from males to other hosts may occur. 6. The percentage of infestation and mean density peak in autumn on H. oregonensis at Bodega Harbor. 7. Ovigerous female hosts are more frequently infested with C. epialti, particularly at small host sizes, than are male or nonovigerous female hosts at Bodega Harbor. However, average worm density on ovigerous females is low. 8. Mean density of C. epialti rises through late postmolt, declines during intermolt and rebuilds to a high level in late premolt H. oregonensisfrom Bodega Harbor. 9. Large crabs have a higher percentage of infestations and mean densities per infection than do small crabs. Nemerteans are more frequently found in the sternal-abdominal furrow and less frequently in the limb axillae on large crabs. 10. A model of C. epialti transmission and site occupancy is proposed, incorporating the influence of host size, sex, reproductive state, embryogenesis, molt cycle stage and molt cycle duration of H. oregonensis at Bodega Harbor. Site availability increases with host size. At higher densities the juvenile nemerteans increasingly occupy less preferred sites. Transferral of juvenile nemerteans occurs

  18. Induction of ketosis in rats fed low-carbohydrate, high-fat diets depends on the relative abundance of dietary fat and protein.

    Science.gov (United States)

    Bielohuby, Maximilian; Menhofer, Dominik; Kirchner, Henriette; Stoehr, Barbara J M; Müller, Timo D; Stock, Peggy; Hempel, Madlen; Stemmer, Kerstin; Pfluger, Paul T; Kienzle, Ellen; Christ, Bruno; Tschöp, Matthias H; Bidlingmaier, Martin

    2011-01-01

    Low-carbohydrate/high-fat diets (LC-HFDs) in rodent models have been implicated with both weight loss and as a therapeutic approach to treat neurological diseases. LC-HFDs are known to induce ketosis; however, systematic studies analyzing the impact of the macronutrient composition on ketosis induction and weight loss success are lacking. Male Wistar rats were pair-fed for 4 wk either a standard chow diet or one of three different LC-HFDs, which only differed in the relative abundance of fat and protein (percentages of fat/protein in dry matter: LC-75/10; LC-65/20; LC-55/30). We subsequently measured body composition by nuclear magnetic resonance (NMR), analyzed blood chemistry and urine acetone content, evaluated gene expression changes of key ketogenic and gluconeogenic genes, and measured energy expenditure (EE) and locomotor activity (LA) during the first 4 days and after 3 wk on the respective diets. Compared with chow, rats fed with LC-75/10, LC-65/20, and LC-55/30 gained significantly less body weight. Reductions in body weight were mainly due to lower lean body mass and paralleled by significantly increased fat mass. Levels of β-hydroxybutyate were significantly elevated feeding LC-75/10 and LC-65/20 but decreased in parallel to reductions in dietary fat. Acetone was about 16-fold higher with LC-75/10 only (P ketosis. LC-HFDs must be high in fat, but also low in protein contents to be clearly ketogenic. Independent of the macronutrient composition, LC-HFD-induced weight loss is not due to increased EE and LA.

  19. Abundance and size changes in the calcareous nannofossil Schizosphaerella - relation to sea-level and palaeoenvironmental change across the Sinemurian to earliest Toarcian of the Paris Basin

    Science.gov (United States)

    Peti, Leonie; Thibault, Nicolas

    2017-04-01

    The nannolith Schizosphaerella spp. was predominant in Early Jurassic calcareous nannofossil assemblages. Previous studies have shown a significant drop in abundance and mean size of Schizosphaerella during the early Toarcian Oceanic Anoxic Event which has been interpreted by some authors either as a calcification crisis due to increased pCO2, or as a response to increased nutrient availability, and/or greenhouse warming. Abundance and size changes in Schizosphaerella have here been thoroughly investigated throughout the upper Sinemurian to lowermost Toarcian (Early Jurassic) of the Sancerre-Couy core (Paris Basin) based on 116 samples. Our results show a stepwise rise in abundance of Schizosphaerella in the lower part of the investigated section and a rise in abundance of coccoliths during the major transgression of the Sinemurian, confirming that Schizosphaerella was better adapted to proximal areas than coccoliths. Mixture analysis of the biometric measurements show the existence of three populations of Schizosphaerella, interpreted as different morphotypes with different ecological affinities. Proximal, cool environmental conditions of the upper Sinemurian are associated with a dominance of the large population of Schizosphaerella. A dominance of the medium population, corresponds to cool surface waters and more distal conditions. Warm episodes are systematically linked to a dominance of the small population. Therefore we propose that the size response of Schizosphaerella throughout the Early Jurassic was rather a change in abundance of different ecophenotypes or (sub-) species of Schizosphaerella, with distinct affinities to temperature and proximal/distal environmental conditions.

  20. Species richness and relative species abundance of Nymphalidae (Lepidoptera in three forests with different perturbations in the North-Central Caribbean of Costa Rica

    Directory of Open Access Journals (Sweden)

    Carolyn Stephen

    2014-09-01

    Full Text Available Measurements of species richness and species abundance can have important implications for regulations and conservation. This study investigated species richness and abundance of butterflies in the family Nymphalidae at undisturbed, and disturbed habitats in Tirimbina Biological Reserve and Nogal Private Reserve, Sarapiquí, Costa Rica. Traps baited with rotten banana were placed in the canopy and the understory of three habitats: within mature forest, at a river/forest border, and at a banana plantation/forest border. In total, 71 species and 487 individuals were caught and identified during May and June 2011 and May 2013. Species richness and species abundance were found to increase significantly at perturbed habitats (p<0.0001, p<0.0001, respectively. The edge effect, in which species richness and abundance increase due to greater complementary resources from different habitats, could be one possible explanation for increased species richness and abundance. Rev. Biol. Trop. 62 (3: 919-928. Epub 2014 September 01.

  1. A salt diapir-related Mississippi Valley-type deposit: the Bou Jaber Pb-Zn-Ba-F deposit, Tunisia: fluid inclusion and isotope study

    Science.gov (United States)

    Bouhlel, Salah; Leach, David L.; Johnson, Craig A.; Marsh, Erin; Salmi-Laouar, Sihem; Banks, David A.

    2016-08-01

    evaporation of seawater to halite saturation and requires a dilution of more than two times by meteoric water. The higher K/Na values in fluid inclusions from barite suggest that the brines interacted with K-rich rocks in the basement or siliciclastic sediments in the basin. Carbonate gangue minerals (ankerite and calcite) have δ13C and δ18O values that are close to the carbonate host rock and indicate fluid equilibrium between carbonate host rocks and hydrothermal brines. The δ34S values for sphalerite and galena fall within a narrow range (1 to 10 ‰) with a bulk value of 7.5 ‰, indicating a homogeneous source of sulfur. The δ34S values of barite are also relatively homogeneous (22 ‰), with 6 ‰ higher than the δ34S of local and regional Triassic evaporites (15 ‰). The latter are believed to be the source of sulfate. Temperature of deposition together with sulfur isotope data indicate that the reduced sulfur in sulfides was derived through thermochemical sulfate reduction of Triassic sulfate via hydrocarbons produced probably from Late Cretaceous source rocks. The 87Sr/86Sr ratio in the Bou Jaber barite (0.709821 to 0.711408) together with the lead isotope values of Bou Jaber galena (206Pb/204Pb = 18.699 to 18.737; 207Pb/204Pb = 15.635 to 15.708 and 208Pb/204Pb = 38.321 to 38.947) show that metals were extracted from homogeneous crustal source(s). The tectonic setting of the Bou Jaber ore deposit, the carbonate nature of the host rocks, the epigenetic style of the mineralization and the mineral associations, together with sulfur and oxygen isotope data and fluid inclusion data show that the Bou Jaber lead-zinc mineralization has the major characteristics of a salt diapir-related Mississippi Valley-type (MVT) deposit with superimposed events of fluorite and of barite deposition. Field relations are consistent with mineral deposition during the Eocene-Miocene Alpine orogeny from multiple hydrothermal events: (1) Zn-Pb sulfides formed by mixing of two fluids: one

  2. A salt diapir-related Mississippi Valley-type deposit: The Bou Jaber Pb-Zn-Ba-F deposit, Tunisia: Fluid inclusion and isotope study

    Science.gov (United States)

    Bouhlel, Salah; Leach, David; Johnson, Craig A.; Marsh, Erin; Salmi-Laouar, Sihem; Banks, David A.

    2016-01-01

    simply by the evaporation of seawater to halite saturation and requires a dilution of more than two times by meteoric water. The higher K/Na values in fluid inclusions from barite suggest that the brines interacted with K-rich rocks in the basement or siliciclastic sediments in the basin. Carbonate gangue minerals (ankerite and calcite) have δ13C and δ18O values that are close to the carbonate host rock and indicate fluid equilibrium between carbonate host rocks and hydrothermal brines. The δ34S values for sphalerite and galena fall within a narrow range (1 to 10 ‰) with a bulk value of 7.5 ‰, indicating a homogeneous source of sulfur. The δ34S values of barite are also relatively homogeneous (22 ‰), with 6 ‰ higher than the δ34S of local and regional Triassic evaporites (15 ‰). The latter are believed to be the source of sulfate. Temperature of deposition together with sulfur isotope data indicate that the reduced sulfur in sulfides was derived through thermochemical sulfate reduction of Triassic sulfate via hydrocarbons produced probably from Late Cretaceous source rocks. The 87Sr/86Sr ratio in the Bou Jaber barite (0.709821 to 0.711408) together with the lead isotope values of Bou Jaber galena (206Pb/204Pb = 18.699 to 18.737;207Pb/204Pb = 15.635 to 15.708 and 208Pb/204Pb = 38.321 to 38.947) show that metals were extracted from homogeneous crustal source(s). The tectonic setting of the Bou Jaber ore deposit, the carbonate nature of the host rocks, the epigenetic style of the mineralization and the mineral associations, together with sulfur and oxygen isotope data and fluid inclusion data show that the Bou Jaber lead-zinc mineralization has the major characteristics of a salt diapir-related Mississippi Valley-type (MVT) deposit with superimposed events of fluorite and of barite deposition. Field relations are consistent with mineral deposition during the Eocene–Miocene Alpine orogeny from multiple hydrothermal events: (1) Zn

  3. Matrix effects in laser ablation molecular isotopic spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Staci, E-mail: staci.brown@cepast.famu.edu [Department of Physics, Florida A and M University, 2077 E. Paul Dirac Drive, Tallahassee, FL 32310 (United States); Ford, Alan, E-mail: alan.ford@alakaidefense.com [Alakai Defense Systems, 197 Replacement Ave, Suite 102, Fort Leonard Wood, MO 65473 (United States); Akpovo, Charlemagne C., E-mail: charlemagne.akpovo@cepast.famu.edu [Department of Physics, Florida A and M University, 2077 E. Paul Dirac Drive, Tallahassee, FL 32310 (United States); Martinez, Jorge, E-mail: jmartinez@cepast.famu.edu [Department of Physics, Florida A and M University, 2077 E. Paul Dirac Drive, Tallahassee, FL 32310 (United States); Johnson, Lewis, E-mail: lewis@cepast.famu.edu [Department of Physics, Florida A and M University, 2077 E. Paul Dirac Drive, Tallahassee, FL 32310 (United States)

    2014-11-01

    Recently, it has been shown that laser-induced breakdown spectroscopy (LIBS) can be used for the detection of isotopes of elements via isotopic shifts in diatomic species in a technique known as laser ablation molecular isotopic spectrometry (LAMIS). While LAMIS works quite well for isotopic analysis of pure compounds under optimal conditions, it is desirable for it to be applicable for a variety of compounds and matrices. However, the LIBS plasma emission associated with LAMIS depends on several parameters, including the applied electric field of the laser pulse, the physical properties of the material being investigated, and the presence of additional elements other than the element of interest. In this paper, we address some of the pitfalls arising from these dependencies when using LAMIS for the determination of the relative isotopic abundance of boron-containing materials with varying chemical matrices. - Highlights: • LAMIS usually determines isotopic composition of boron compounds within 3 percent. • LaBO{sub 3} and some boron-containing mixtures yield inaccurate LAMIS results. • Higher laser energy reduces variability but does not remedy poor LAMIS outcomes.

  4. Application of Stable Isotope Signatures in Food Traceability

    International Nuclear Information System (INIS)

    Nazaratul Ashifa Abdullah Salim; Roslanzairi Mostapha; Zainon Othman

    2016-01-01

    Stable isotope analysis has widely been used to trace the origin of organic materials in various fields, such as geochemistry, biochemistry, archaeology and petroleum. In past a decade, it has also become an important tool for food traceability study. The globalisation of food markets and the relative ease which food commodities are transported through and between countries and continents means that consumers are increasingly concerned about the origin of the foods they eat. The natural abundance of stable isotope variation such as carbon, nitrogen, hydrogen and oxygen are used as geographic tracers or marker to determine the geographic origin of fruits, crop, vegetables and food products from animal. The isotopic compositions of plant materials reflect various factors such as isotopic compositions of source materials and their assimilation processes as well as growth environments. This paper will discuss on stable carbon and nitrogen isotopic compositions in rice that been determined by Isotope Ratio Mass Spectrometry, advantages, limitations and potential of other analysis applications that can be incorporated in food traceability system. (author)

  5. Intracellular Cadmium Isotope Fractionation

    Science.gov (United States)

    Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

    2011-12-01

    Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

  6. Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples.

    Science.gov (United States)

    Godin, Jean-Philippe; Breuillé, Denis; Obled, Christiane; Papet, Isabelle; Schierbeek, Henk; Hopfgartner, Gérard; Fay, Laurent-Bernard

    2008-10-01

    On-line gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is commonly used to measure isotopic ratios at natural abundance as well as for tracer studies in nutritional and medical research. However, high-precision (13)C isotopic enrichment can also be measured by liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). Indeed, LC-IRMS can be used, as shown by the new method reported here, to obtain a baseline separation and to measure (13)C isotopic enrichment of underivatised amino acids (Asp, Thr-Ser, Glu, Pro, Gly, Ala, Cys and Val). In case of Val, at natural abundance, the SD(delta(13)C) reported with this method was found to be below 1 per thousand . Another key feature of the new LC-IRMS method reported in this paper is the comparison of the LC-IRMS approach with the conventional GC-C-IRMS determination. To perform this comparative study, isotopic enrichments were measured from underivatised Val and its N(O, S)-ethoxycarbonyl ethyl ester derivative. Between 0.0 and 1.0 molar percent excess (MPE) (delta(13)C= -12.3 to 150.8 per thousand), the calculated root-mean-square (rms) of SD was 0.38 and 0.46 per thousand and the calculated rms of accuracy was 0.023 and 0.005 MPE, respectively, for GC-C-IRMS and LC-IRMS. Both systems measured accurately low isotopic enrichments (0.002 atom percent excess (APE)) with an SD (APE) of 0.0004. To correlate the relative (delta(13)C) and absolute (atom%, APE and MPE) isotopic enrichment of Val measured by the GC-C-IRMS and LC-IRMS devices, mathematical equations showing the slope and intercept of the curves were established and validated with experimental data between 0.0 to 2.3 MPE. Finally, both GC-C-IRMS and LC-IRMS instruments were also used to assess isotopic enrichment of protein-bound (13)C-Val in tibial epiphysis in a tracer study performed in rats. Isotopic enrichments measured by LC-IRMS and GC-C-IRMS were not statistically different (p>0.05). The results of this work indicate that

  7. Isotopically labelled pyrimidines and purines

    International Nuclear Information System (INIS)

    Balaban, A.T.; Bally, I.

    1987-01-01

    Among the three diazines, pyrimidine is by far the most important one because its derivatives uracil, thymine and cytosine are constituents of the ubiquitous deoxynucleic acids (DNA) and ribonucleic acids (RNA). Other derivatives of pyrimidine without condensed rings include barbiturates, alloxan, orotic acid and thiamine or vitamin B 1 . From the polycyclic derivatives of pyrimidine such as pteridine, alloxazine, and purine, the latter, through its derivatives adenine and guanine complete the list of bases which occur in DNA and RNA: in addition, other purine derivatives such as hypoxanthine, xanthine, theobromine, theophylline, caffeine and uric acid are important natural products with biological activity. The paper presents methods for preparing isotopically labeled pyrimidines as well as purine derivatives. For convenience, the authors describe separately carbon-labeled with radioisotopes 11 C (T 1/2 = 20.3 min) and 14 C (T 1/2 = 5736 years) or the stable isotope 13 C (natural abundance 1.1%) and then hydrogen-labeled systems with the radioisotope 3 H ≡ T (T 1/2 = 12.346 years) or with the stable isotope 2 H ≡ D (natural abundance 0.015%). We do not separate stable from radioactive isotopes because the synthetic methods are identical for the same element; however, the introduction of hydrogen isotopes into organic molecules is often performed by reactions such as isotope exchange which cannot take place in the case of carbon isotopes

  8. Distribution and abundance of the Lesser electric ray Narcine brasiliensis (Olfers, 1831 (Elasmobranchii: Narcinidae in southern Brazil in relation to environmental factors

    Directory of Open Access Journals (Sweden)

    Gabriel Maciel de Souza Vianna

    2009-06-01

    Full Text Available The distribution and abundance of the lesser electric ray, Narcine brasiliensis, was assessed based on bottom-trawl survey data collected off the coast of Rio Grande do Sul, southern Brazil. Between 1980 and 1984 and in 2005, 416 bottom trawl hauls were carried out at depths of 10-100 m. Narcine brasiliensis occurred mainly in waters with bottom temperature between 20 and 25ºC. Density of the species was higher between the depths of 10 and 20 m, during the summer and autumn. The seasonal pattern of N. brasiliensis in the shallow coastal water of Rio Grande do Sul reflects a southward migration in summer. This is conditioned by the southward advance of warmer and high-salinity Tropical Water of the Brazil Current In winter, the return or northward migration is a response to seasonal cooling of the coastal waters and to the northward advance of cold Coastal Water of lower salinity. The latitudinal gradient in density of N. brasiliensis was related to the latitudinal gradient in salinity of the bottom waters. This was caused by the freshwater runoff from the Patos Lagoon establishing a physical barrier to the occurrence of the species farther south than the city of Rio Grande.A distribuição e abundância da raia elétrica Narcine brasiliensis foi analisada com base em 416 lances de arrasto de fundo realizados entre as profundidades de 10- 100 m ao longo da costa do Rio Grande do Sul, em 1980-1984 e 2005. A espécie ocorreu prioritariamente em águas com temperatura de fundo entre 20 e 25ºC. A densidade de N. brasiliensis foi maior durante o verão e outono e entre as profundidades de 10 e 20 m. O padrão sazonal de densidade da espécie nas águas costeiras rasas do Rio Grande do Sul reflete uma migração no sentido norte-sul condicionada pelo avanço das águas quentes e de alta salinidade da Água Tropical da Corrente do Brasil em direção ao sul durante o verão. A redução sazonal da temperatura da água e o avanço da Água Costeira, de

  9. The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

    Science.gov (United States)

    Bayon, G.; Delvigne, C.; Ponzevera, E.; Borges, A. V.; Darchambeau, F.; De Deckker, P.; Lambert, T.; Monin, L.; Toucanne, S.; André, L.

    2018-05-01

    The δ30Si stable isotopic composition of silicon in soils and fine-grained sediments can provide insights into weathering processes on continents, with important implications on the Si budget of modern and past oceans. To further constrain the factors controlling the distribution of Si isotopes in sediments, we have analysed a large number (n = 50) of separate size-fractions of sediments and suspended particulate materials collected near the mouth of rivers worldwide. This includes some of the world's largest rivers (e.g. Amazon, Congo, Mackenzie, Mississippi, Murray-Darling, Nile, Yangtze) and rivers from the case study areas of the Congo River Basin and Northern Ireland. Silt-size fractions exhibit a mean Si isotopic composition (δ30Si = -0.21 ± 0.19‰; 2 s.d.) similar to that previously inferred for the upper continental crust. In contrast, clay-size fractions display a much larger range of δ30Si values from -0.11‰ to -2.16‰, which yield a global δ30Siclay of -0.57 ± 0.60‰ (2 s.d.) representative of the mean composition of the average weathered continental crust. Overall, these new data show that the Si isotopic signature transported by river clays is controlled by the degree of chemical weathering, as inferred from strong relationships with Al/Si ratios. At a global scale, the clay-bound Si isotopic composition of the world's largest river systems demonstrates a link with climate, defining a general correlation with mean annual temperature (MAT) in corresponding drainage basins. While the distribution of Si isotopes in river sediments also appears to be influenced by the tectonic setting, lithological effects and sediment recycling from former sedimentary cycles, our results pave the way for their use as paleo-weathering and paleo-climate proxies in the sedimentary record.

  10. Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

    Science.gov (United States)

    Fabisch, Maria; Beulig, Felix; Akob, Denise M.; Küsel, Kirsten

    2013-01-01

    We identified and quantified abundant iron-oxidizing bacteria (FeOB) at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7), to moderately acidic (R2, pH 4.4), to slightly acidic (R3, pH 6.3) in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U) bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic “Ferrovum myxofaciens” was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and “Ferrovum myxofaciens” revealed that ~72% (R2 sediment) and 37% (R3 sediment) of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

  11. Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

    Directory of Open Access Journals (Sweden)

    Maria eFabisch

    2013-12-01

    Full Text Available We identified and quantified abundant iron-oxidizing bacteria (FeOB at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7, to moderately acidic (R2, pH 4.4, to slightly acidic (R3, pH 6.3 in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic ‘Ferrovum myxofaciens’ was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and ‘Ferrovum myxofaciens’ revealed that approximately 72% (R2 sediment and 37% (R3 sediment of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

  12. Eurisol-DS Multi-MW target A proposal for improving overall performance in relation to the isotope yield

    CERN Document Server

    Samec, K; Kadi, Yacine; Rocca, Roberto; Kharoua, Cyril

    2008-01-01

    The Eurisol Design Study has been initiated by the European Commission to demonstrate the feasibility of a facility for producing large yields of exotic isotopes. At the core of the projected facility, the neutron source produces spallation neutrons from a proton beam impacting dense liquid metal. The neutrons emitted from the source are used to fission Uranium targets which, in turn, produce high yields of isotopes. This technical report summarises efforts to improve the overall performance of the planned facility, by optimising the neutron source and the disposition of the fission targets.

  13. EURISOL-DS Multi-MW Target. A proposal for improving overall performance in relation to the isotope yield

    CERN Document Server

    Karel Samec, Mats Lindroos, Yacine Kadi,Roberto Rocca, Cyril KharouaAB Dept. ATB

    The Eurisol Design Study has been initiated by the European Commission to demonstratethe feasibility of a facility for producing large yields of exotic isotopes.At the core of the projected facility, the neutron source produces spallation neutrons from aproton beam impacting dense liquid metal. The neutrons emitted from the source are usedto fission Uranium targets which, in turn, produce high yields of isotopes.This technical report summarises efforts to improve the overall performance of the plannedfacility, by optimising the neutron source and the disposition of the fission targets.

  14. Environmental isotope studies related to groundwater flow and saline encroachment in the chalk aquifer of Lincolnshire, England

    International Nuclear Information System (INIS)

    Lloyd, J.W.; Howard, K.W.F.

    1978-01-01

    The isotopes of tritium and carbon are used to study part of the North Lincolnshire Chalk aquifer in England. The tritium data support the view that the aquifer is a thin fissure system and indicate that some changes in flow direction have occurred due to recent abstraction. The data are also consistent with other chemical data in elucidating groundwater entering the Chalk from deeper aquifers. Carbon isotopes are used to distinguish between saline water bodies and suggest that saline water was entrapped within the aquifer in the Eemian and Flandrian stages of the Pleistocene. (orig.) [de

  15. Nonequilibrium clumped isotope signals in microbial methane

    Science.gov (United States)

    Wang, David T.; Gruen, Danielle S.; Lollar, Barbara Sherwood; Hinrichs, Kai-Uwe; Stewart, Lucy C.; Holden, James F.; Hristov, Alexander N.; Pohlman, John W.; Morrill, Penny L.; Könneke, Martin; Delwiche, Kyle B.; Reeves, Eoghan P.; Sutcliffe, Chelsea N.; Ritter, Daniel J.; Seewald, Jeffrey S.; McIntosh, Jennifer C.; Hemond, Harold F.; Kubo, Michael D.; Cardace, Dawn; Hoehler, Tori M.; Ono, Shuhei

    2015-01-01

    Methane is a key component in the global carbon cycle with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply-substituted “clumped” isotopologues, e.g., 13CH3D, has recently emerged as a proxy for determining methane-formation temperatures; however, the impact of biological processes on methane’s clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on 13CH3D abundances and results in anomalously elevated formation temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.

  16. 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)

  17. Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-related matrix effect; SHRIMP, ID-TIMS, ELA-ICP-MS and oxygen isotope documentation for a series of zircon standards

    Science.gov (United States)

    Black, L.P.; Kamo, S.L.; Allen, C.M.; Davis, D.W.; Aleinikoff, J.N.; Valley, J.W.; Mundil, R.; Campbell, I.H.; Korsch, R.J.; Williams, I.S.; Foudoulis, C.

    2004-01-01

    Precise isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) documentation is given for two new Palaeozoic zircon standards (TEMORA 2 and R33). These data, in combination with results for previously documented standards (AS3, SL13, QGNG and TEMORA 1), provide the basis for a detailed investigation of inconsistencies in 206Pb/238U ages measured by microprobe. Although these ages are normally consistent between any two standards, their relative age offsets are often different from those established by ID-TIMS. This is true for both sensitive high-resolution ion-microprobe (SHRIMP) and excimer laser ablation-inductively coupled plasma-mass spectrometry (ELA-ICP-MS) dating, although the age offsets are in the opposite sense for the two techniques. Various factors have been investigated for possible correlations with age bias, in an attempt to resolve why the accuracy of the method is worse than the indicated precision. Crystallographic orientation, position on the grain-mount and oxygen isotopic composition are unrelated to the bias. There are, however, striking correlations between the 206Pb/238U age offsets and P, Sm and, most particularly, Nd abundances in the zircons. Although these are not believed to be the primary cause of this apparent matrix effect, they indicate that ionisation of 206Pb/238U is influenced, at least in part, by a combination of trace elements. Nd is sufficiently representative of the controlling trace elements that it provides a quantitative means of correcting for the microprobe age bias. This approach has the potential to reduce age biases associated with different techniques, different instrumentation and different standards within and between laboratories. Crown Copyright ?? 2004 Published by Elsevier B.V. All rights reserved.

  18. Relative abundance of small mammals in nest core areas and burned wintering areas of Mexican spotted owls in the Sacramento Mountains, New Mexico

    Science.gov (United States)

    Joseph L. Ganey; Sean C. Kyle; Todd A. Rawlinson; Darrell L. Apprill; James P Ward

    2014-01-01

    Mexican Spotted Owls (Strix occidentalis lucida) are common in older forests within their range but also persist in many areas burned by wildfire and may selectively forage in these areas. One hypothesis explaining this pattern postulates that prey abundance increases in burned areas following wildfire. We observed movement to wintering areas within areas burned by...

  19. TITANIUM ISOTOPE SOURCE RELATIONS AND THE EXTENT OF MIXING IN THE PROTO-SOLAR NEBULA EXAMINED BY INDEPENDENT COMPONENT ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Steele, Robert C. J.; Boehnke, Patrick [Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095 (United States)

    2015-04-01

    The Ti isotope variations observed in hibonites represent some of the largest isotope anomalies observed in the solar system. Titanium isotope compositions have previously been reported for a wide variety of different early solar system materials, including calcium, aluminum rich inclusions (CAIs) and CM hibonite grains, some of the earliest materials to form in the solar system, and bulk meteorites which formed later. These data have the potential to allow mixing of material to be traced between many different regions of the early solar system. We have used independent component analysis to examine the mixing end-members required to produce the compositions observed in the different data sets. The independent component analysis yields results identical to a linear regression for the bulk meteorites. The components identified for hibonite suggest that most of the grains are consistent with binary mixing from one of three highly anomalous nucleosynthetic sources. Comparison of these end-members show that the sources which dominate the variation of compositions in the meteorite parent body forming regions was not present in the region in which the hibonites formed. This suggests that the source which dominates variation in Ti isotope anomalies between the bulk meteorites was not present when the hibonite grains were forming. One explanation is that the bulk meteorite source may not be a primary nucleosynthetic source but was created by mixing two or more of the hibonite sources. Alternatively, the hibonite sources may have been diluted during subsequent nebula processing and are not a dominant solar system signatures.

  20. Relative Abundance and Plasmodium Infection Rates of Malaria Vectors in and around Jabalpur, a Malaria Endemic Region in Madhya Pradesh State, Central India.

    Science.gov (United States)

    Singh, Neeru; Mishra, Ashok K; Chand, Sunil K; Bharti, Praveen K; Singh, Mrigendra P; Nanda, Nutan; Singh, Om P; Sodagiri, Kranti; Udhyakumar, Venkatachalam

    2015-01-01

    This study was undertaken in two Primary Health Centers (PHCs) of malaria endemic district Jabalpur in Madhya Pradesh (Central India). In this study we had investigated the relative frequencies of the different anopheline species collected within the study areas by using indoor resting catches, CDC light trap and human landing methods. Sibling species of malaria vectors were identified by cytogenetic and molecular techniques. The role of each vector and its sibling species in the transmission of the different Plasmodium species was ascertained by using sporozoite ELISA. A total of 52,857 specimens comprising of 17 anopheline species were collected by three different methods (39,964 by indoor resting collections, 1059 by human landing and 11,834 by CDC light trap). Anopheles culicifacies was most predominant species in all collections (55, 71 and 32% in indoor resting, human landing and light trap collections respectively) followed by An. subpictus and An. annularis. All five sibling species of An. culicifacies viz. species A, B, C, D and E were found while only species T and S of An. fluviatilis were collected. The overall sporozoite rate in An. culicifacies and An. fluviatilis were 0.42% (0.25% for P. falciparum and 0.17% for P. vivax) and 0.90% (0.45% for P. falciparum and 0.45% for P. vivax) respectively. An. culicifacies and An. fluviatilis were found harbouring both P. vivax variants VK-210 and VK-247, and P. falciparum. An. culicifacies sibling species C and D were incriminated as vectors during most part of the year while sibling species T of An. fluviatilis was identified as potential vector in monsoon and post monsoon season. An. culicifacies species C (59%) was the most abundant species followed by An. culicifacies D (24%), B (8.7%), E (6.7%) and A (1.5%). Among An. fluviatilis sibling species, species T was common (99%) and only few specimens of S were found. Our study provides crucial information on the prevalence of An. culicifacies and An. fluviatilis

  1. Relative Abundance and Plasmodium Infection Rates of Malaria Vectors in and around Jabalpur, a Malaria Endemic Region in Madhya Pradesh State, Central India.

    Directory of Open Access Journals (Sweden)

    Neeru Singh

    Full Text Available This study was undertaken in two Primary Health Centers (PHCs of malaria endemic district Jabalpur in Madhya Pradesh (Central India.In this study we had investigated the relative frequencies of the different anopheline species collected within the study areas by using indoor resting catches, CDC light trap and human landing methods. Sibling species of malaria vectors were identified by cytogenetic and molecular techniques. The role of each vector and its sibling species in the transmission of the different Plasmodium species was ascertained by using sporozoite ELISA.A total of 52,857 specimens comprising of 17 anopheline species were collected by three different methods (39,964 by indoor resting collections, 1059 by human landing and 11,834 by CDC light trap. Anopheles culicifacies was most predominant species in all collections (55, 71 and 32% in indoor resting, human landing and light trap collections respectively followed by An. subpictus and An. annularis. All five sibling species of An. culicifacies viz. species A, B, C, D and E were found while only species T and S of An. fluviatilis were collected. The overall sporozoite rate in An. culicifacies and An. fluviatilis were 0.42% (0.25% for P. falciparum and 0.17% for P. vivax and 0.90% (0.45% for P. falciparum and 0.45% for P. vivax respectively. An. culicifacies and An. fluviatilis were found harbouring both P. vivax variants VK-210 and VK-247, and P. falciparum. An. culicifacies sibling species C and D were incriminated as vectors during most part of the year while sibling species T of An. fluviatilis was identified as potential vector in monsoon and post monsoon season.An. culicifacies species C (59% was the most abundant species followed by An. culicifacies D (24%, B (8.7%, E (6.7% and A (1.5%. Among An. fluviatilis sibling species, species T was common (99% and only few specimens of S were found. Our study provides crucial information on the prevalence of An. culicifacies and An

  2. Relative Abundances of Calcite and Silica in Fracture Coatings as a Possible Indicator of Evaporation in a Thick Unsaturated Zone, Yucca Mountain, Nevada

    Science.gov (United States)

    Marshall, B. D.; Moscati, R. J.

    2005-12-01

    Yucca Mountain, a ridge of shallowly dipping, Miocene-age volcanic rocks in southwest Nevada, is the proposed site for a nuclear waste repository to be constructed in the 500- to 700-m-thick unsaturated zone (UZ). At the proposed repository, the 300-m-thick Topopah Spring Tuff welded unit (TSw) is overlain by approximately 30 m of nonwelded tuffs (PTn); the Tiva Canyon Tuff welded unit (TCw) overlies the PTn with a range in thickness from 0 to approximately 130 m at the site. The amount of water percolation through the UZ is low and difficult to measure directly, but local seepage into mined tunnels has been observed in the TCw. Past water seepage in the welded tuffs is recorded by widespread, thin (0.3 cm) coatings of calcite and silica on fracture surfaces and within cavities. Abundances of calcite and silica in the coatings were determined by X-ray microfluorescence mapping and subsequent multispectral image analysis of over 200 samples. The images were classified into constituent phases including opal-chalcedony-quartz (secondary silica) and calcite. In the TCw samples, the median calcite/silica ratio is 8; in the TSw samples within 35 m below the PTn, median calcite/silica falls to 2, perhaps reflecting an increase in soluble silica from the presence of glass in the nonwelded tuffs. In the deeper parts of the TSw, median calcite/silica reaches 100 and many samples contain no detectable secondary silica phase. Evaporation and changing pCO2 control precipitation of calcite from water percolating downward in the UZ, but precipitation of opal requires only evaporation. Calcite/silica ratios, therefore, can constrain the relative importance of evaporation in the UZ. Although calcite/silica values scatter widely within the TSw, reflecting the spatial variability of gas and water flow, average calcite/silica ratios increase with stratigraphic depth, indicating less evaporation at the deeper levels of the UZ. Coupled with the much smaller calcite/silica ratios

  3. Stable isotope enrichment: Current and future potential

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.S.

    1992-01-01

    Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities

  4. Stable isotope enrichment - current and future potential

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.S.

    1993-01-01

    Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL. This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities. (orig.)

  5. Isotopic compositions of the elements 2013 (IUPAC Technical Report)

    Science.gov (United States)

    Meija, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna; Loss, Robert D.; Walczyk, Thomas; Prohaska, Thomas

    2016-01-01

    The Commission on Isotopic Abundances and Atomic Weights (ciaaw.org) of the International Union of Pure and Applied Chemistry (iupac.org) has revised the Table of Isotopic Compositions of the Elements (TICE). The update involved a critical evaluation of the recent published literature. The new TICE 2013 includes evaluated data from the “best measurement” of the isotopic abundances in a single sample, along with a set of representative isotopic abundances and uncertainties that accommodate known variations in normal terrestrial materials.

  6. Validation of chlorine and oxygen isotope ratio analysis to differentiate perchlorate sources and to document perchlorate biodegradation

    Science.gov (United States)

    Paul B. Hatzinger,; Böhlke, John Karl; Sturchio, Neil C.; Gu, Baohua

    2013-01-01

    Increased health concerns about perchlorate (ClO4-) during the past decade and subsequent regulatory considerations have generated appreciable interest in source identification. The key objective of the isotopic techniques described in this guidance manual is to provide evidence concerning the origin of ClO4- in soils and groundwater an