δ15N value does not reflect fasting in mysticetes.

Science.gov (United States)

Aguilar, Alex; Giménez, Joan; Gómez-Campos, Encarna; Cardona, Luís; Borrell, Asunción

2014-01-01

The finding that tissue δ(15)N values increase with protein catabolism has led researchers to apply this value to gauge nutritive condition in vertebrates. However, its application to marine mammals has in most occasions failed. We investigated the relationship between δ(15)N values and the fattening/fasting cycle in a model species, the fin whale, a migratory capital breeder that experiences severe seasonal variation in body condition. We analyzed two tissues providing complementary insights: one with isotopic turnover (muscle) and one that keeps a permanent record of variations in isotopic values (baleen plates). In both tissues δ(15)N values increased with intensive feeding but decreased with fasting, thus contradicting the pattern previously anticipated. The apparent inconsistency during fasting is explained by the fact that a) individuals migrate between different isotopic isoscapes, b) starvation may not trigger significant negative nitrogen balance, and c) excretion drops and elimination of 15N-depleted urine is minimized. Conversely, when intensive feeding is resumed in the northern grounds, protein anabolism and excretion start again, triggering 15N enrichment. It can be concluded that in whales and other mammals that accrue massive depots of lipids as energetic reserves and which have limited access to drinking water, the δ15N value is not affected by fasting and therefore cannot be used as an indication of nutritive condition.

Measuring and predicting Delta(vap)H298 values of ionic liquids.

Science.gov (United States)

Deyko, Alexey; Lovelock, Kevin R J; Corfield, Jo-Anne; Taylor, Alasdair W; Gooden, Peter N; Villar-Garcia, Ignacio J; Licence, Peter; Jones, Robert G; Krasovskiy, Vladimir G; Chernikova, Elena A; Kustov, Leonid M

2009-10-14

We report the enthalpies of vaporisation (measured using temperature programmed desorption by mass spectrometry) of twelve ionic liquids (ILs), covering four imidazolium, [C(m)C(n)Im]+, five pyrrolidinium, [C(n)C(m)Pyrr]+, two pyridinium, [C(n)Py]+, and a dication, [C3(C1Im)2]2+ based IL. These cations were paired with a range of anions: [BF4]-, [FeCl4]-, [N(CN)2]-, [PF3(C2F5)3]- ([FAP]-), [(CF3SO2)2N]- ([Tf2N]-) and [SCN]-. Using these results, plus those for a further eight imidazolium based ILs published earlier (which include the anions [CF3SO3]- ([TfO]-), [PF6]- and [EtSO4]-), we show that the enthalpies of vaporisation can be decomposed into three components. The first component is the Coulombic interaction between the ions, DeltaU(Cou,R), which is a function of the IL molar volume, V(m), and a parameter R(r) which quantifies the relative change in anion-cation distance on evaporation from the liquid phase to the ion pair in the gas phase. The second and third components are the van der Waals contributions from the anion, DeltaH(vdw,A), and the cation, DeltaH(vdw,C). We derive a universal value for R(r), and individual values of DeltaH(vdw,A) and DeltaH(vdw,C) for each of the anions and cations considered in this study. Given the molar volume, it is possible to estimate the enthalpies of vaporisation of ILs composed of any combination of the ions considered here; values for fourteen ILs which have not yet been studied experimentally are given.

Seasonal mercury concentrations and {delta}{sup 15}N and {delta}{sup 13}C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

Energy Technology Data Exchange (ETDEWEB)

Diaz-Jaramillo, Mauricio, E-mail: mdiazjaramillo@conicet.gov.ar [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Munoz, Claudia; Rudolph, Ignacio [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Servos, Mark [Department of Biology, University of Waterloo, ON (Canada); Barra, Ricardo [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile)

2013-01-01

The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C). Mercury concentrations in Lenga sediments ranged from 0.4 {+-} 0.1 to 13 {+-} 3 mg/kg, while those in Tubul sediments ranged from 0.02 {+-} 0.01 to 0.07 {+-} 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p < 0.05), but not by species or season for each estuary (p > 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of {delta}{sup 13}C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: Black-Right-Pointing-Pointer Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. Black-Right-Pointing-Pointer Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. Black-Right-Pointing-Pointer Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. Black-Right-Pointing-Pointer Interspecific variation in {delta}{sup 13}C signatures indicated different feeding modes. Black

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

Using Whole Stream {delta}{sup 15}N Additions to Understand the Effects of Land Use Change on Stream Function

Energy Technology Data Exchange (ETDEWEB)

Deegan, L. A.; Neill, C.; Thomas, S.; Haupert, C. [Marine Biological Laboratory, Woods Hole, MA (United States); Victoria, R. L.; Krusche, A. V.; Ballester, M. V.R. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Sao Paulo (Brazil)

2013-05-15

In this paper we introduce an emerging new technique; the use of {delta}{sup 15}N stable isotope tracers to understand both short term and long term alterations in stream ecosystem nitrogen biogeochemistry and food web dynamics. The use of {delta}{sup 15}N isotopes to determine stream nitrogen cycling was developed in small tundra streams in Alaska (USA), but a network of researchers using similar technique has rapidly grown to answer questions about nitrogen cycling and stream food webs in a variety of ecosystem types and subject to human modifications. Here we provide an overview of some of the information that can be provided using stable isotope additions and describe the general approach of an isotope addition experiment. To illustrate the scope of isotope applicability some examples are provided of work undertaken in the Brazilian Amazon. (author)

N isotopes and N cycle in the TieShanPing subtropical forest ecosystem, Southwestern China.

Science.gov (United States)

Jiang, Chun-lai; Zhang, Xiao-Shan

2009-07-01

Nitrogen is essential for forest growth and forest stand development. It is commonly a limited factor for forest productivity. We examined delta (15)N values in soils and plants by studying the sources of N used by vegetation and cycles of N in a 43-year-old plantation of the TieShanPing forest ecosystem in southwestern China, dominated by massone pine (Pinus massoniana). The N concentration of plant materials ranges from 1.1% to 2.2%. The nitrogen concentration of P. massoniana was 1.3% while soils showed the concentration of 0.04-0.15%. Regarding natural abundance of (15)N, large significant variation (-6.0 per thousand to -3.8 per thousand) in delta (15)N values was observed among shrub and tree leaves. delta (15)N values were also significantly varied from -4.7 per thousand to -3.8 per thousand among the pioneer species in the plantation. Soil delta (15)N values (3.1-6.3 per thousand) were significantly enriched compared to those values in plant samples. Despite the negative delta (15)N values of the vegetation cover, the high delta (15)N values in the topsoil indicate that return of N to soils by litter-fall is minimal on TieShanPing and the present forests do not change very much the soil (15)N signals at the surface layer. The positive delta (15)N values may also indicate large N losses from the soil system vial leaching, volatilization and plant uptake.

Thermodynamic constants of N-[tris(hydroxymethyl)methyl-3-amino]propanesulfonic acid (Taps) from the temperatures 278.15 K to 328.15 K

Energy Technology Data Exchange (ETDEWEB)

Roy, Rabindra N. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States)]. E-mail: rroy@drury.edu; Roy, Lakshmi N. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States); LeNoue, Sean R. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States); Denton, Cole E. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States); Simon, Ashley N. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States); Richards, Sarah J. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States); Moore, Andrew C. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States); Roy, Chandra N. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States); Redmond, R. Ryan [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States); Bryant, Paul A. [Walter H. Hoffman Department of Chemistry, Drury University, 900 N. Benton Avenue, Springfield, MO 65802 (United States)

2006-04-15

Values of the second thermodynamic dissociation constant pK{sub 2} of N-[tris(hydroxymethyl)methyl-3-amino]propanesulfonic acid (Taps) have been determined at twelve temperatures from 278.15 K to 328.15 K including 310.15 K by measurements of the electromotive-force for cells without liquid junction of the type: Pt|H{sub 2} (g, p{sup -}bar =101.325 kPa)|Taps (m{sub 1}), NaTapsate (m{sub 2}), NaCl (m{sub 3})|AgCl|Ag, where m denotes molality. The pK{sub 2} values for the dissociation of Taps are represented by the equation: pK{sub 2}=2969.61.(K/T) - 17.05052+2.73697.ln(T/K). The values of pK{sub 2} for Taps were found to be (8.502+/-0.0007) at T=298.15 K and (8.225+/-0.0009) at T=310.15 K, respectively, indicating thereby to be useful as buffer solutions for pH control in the region 7.4 to 8.5. The thermodynamic quantities, {delta}G{sup -}bar , {delta}H{sup -}bar , {delta}S{sup -}bar , and {delta}C{sub p}{sup -}bar dissociation process of Taps have been derived from the temperature coefficients of the pK{sub 2}.

USING delta15N OF CHIRONOMIDAE TO HELP ASSESS CONDITION AND STRESSORS IN LAKES, RIVERS AND STREAMS OF THE UNITED STATES.

Science.gov (United States)

To assess large-scale ecological conditions efficiently, indicators that can be collected quickly at many sites need to be developed. We explore the utility of delta 15N from basal food chain organisms to provide information on N loading and processing in lakes, rivers and stream...

Tissue N content and {sup 15}N natural abundance in epilithic mosses for indicating atmospheric N deposition in the Guiyang area, SW China

Energy Technology Data Exchange (ETDEWEB)

Liu Xueyan [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China)], E-mail: liuxueyan@vip.skleg.cn; Xiao Huayun [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)], E-mail: xiaohuayun@vip.skleg.cn; Liu Congqiang [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Li Youyi; Xiao Hongwei [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China)

2008-09-15

Tissue N contents and {delta}{sup 15}N signatures in 175 epilithic mosses were investigated from urban to rural sites in Guiyang (SW China) to determine atmospheric N deposition. Moss N contents (0.85-2.97%) showed a significant decrease from the urban area (mean = 2.24 {+-} 0.32%, 0-5 km) to the rural area (mean = 1.27 {+-} 0.13%, 20-25 km), indicating that the level of N deposition decreased away from the urban environment, while slightly higher N contents re-occurred at sites beyond 30 km, suggesting higher N deposition in more remote rural areas. Moss {delta}{sup 15}N ranged from -12.50 per mille to -1.39 per mille and showed a clear bimodal distribution (-12 per mille to -6 per mille and -5 per mille to -2 per mille ), suggesting that there are two main sources for N deposition in the Guiyang area. More negative {delta}{sup 15}N (mean = -8.87 {+-} 1.65 per mille ) of urban mosses mainly indicated NH{sub 3} released from excretory wastes and sewage, while the less negative {delta}{sup 15}N (from -3.83 {+-} 0.82 per mille to -2.48 {+-} 0.95 per mille ) of rural mosses were mainly influenced by agricultural NH{sub 3}. With more negative values in the urban area than in the rural area, the pattern of moss {delta}{sup 15}N variation in Guiyang was found to be opposite to cities where N deposition is dominated by NO{sub x}-N. Therefore, NH{sub x}-N is the dominant N form deposited in the Guiyang area, which is supported by higher NH{sub x}-N than NO{sub x}-N in local atmospheric deposition. From the data showing that moss is responding to NH{sub x}-N/NO{sub x}-N in deposition it can be further demonstrated that the variation of moss {delta}{sup 15}N from the Guiyang urban to rural area was more likely controlled by the ratio of urban-NH{sub x}/agriculture-NH{sub x} than the ratio of NH{sub x}-N/NO{sub x}-N. The results of this study have extended knowledge of atmospheric N sources in city areas, showing that urban sewage discharge could be important in cities co

Interannual changes in δ15N values in Fucus vesiculosus L

International Nuclear Information System (INIS)

Carballeira, Carlos; Rey-Asensio, Ana; Carballeira, Alejo

2014-01-01

Highlights: • Isotopic values change along the thallus of F. vesiculosus. • δ 15 N values along the thallus are different between control and polluted sites. • δ 15 N values are temporally unstable at polluted sites. - Abstract: The natural abundance of 15 N (δ 15 N) has been widely used to detect anthropogenically derived N loads in environmental impact studies. The present study involved retrospective analysis of subsamples of Fucus vesiculosus L. collected during a period of three years (2008–2010) from two sites: a control site, within a coastal reference area, and an area affected by the effluents of a marine land-based fish farm. The isotopic signal in different subsamples of the macroalgae thalli (tissue that has grown during the same period) varied depending on the age of the tissue. Moreover, the isotopic signal decreased significantly with the age of the frond to within a certain range. The δ 15 N of F. vesiculosus is temporally unstable; therefore, measurement of the δ 15 N of macroalgal tissues does not allow reliable retrospective biomonitoring of environmental pollution. Further knowledge about the growth and other biological aspects of this species is required

N* and {delta}* decays into N{pi}{sup 0}{pi}{sup 0}

Energy Technology Data Exchange (ETDEWEB)

Thoma, U. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); II. Physikalisches Institut, Universitaet Giessen (Germany); Fuchs, M. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Anisovich, A.V. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Anton, G. [Physikalisches Institut, Universitaet Erlangen (Germany); Bantes, R. [Physikalisches Institut, Universitaet Bonn (Germany); Bartholomy, O.; Beck, R. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Beloglazov, Yu. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Crede, V. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Department of Physics, Florida State University (United States); Ehmanns, A.; Ernst, J.; Fabry, I. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Flemming, H. [Physikalisches Institut, Universitaet Bochum (Germany); Foesel, A. [Physikalisches Institut, Universitaet Erlangen (Germany); Funke, Chr. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Gothe, R. [Physikalisches Institut, Universitaet Bonn (Germany); Gridnev, A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Gutz, E. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Hoeffgen, St. [Physikalisches Institut, Universitaet Bonn (Germany); Horn, I. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany)] (and others)

2008-01-17

Decays of baryon resonances in the second and the third resonance region into N{pi}{sup 0}{pi}{sup 0} are studied by photoproduction of two neutral pions off protons. Partial decay widths of N* and {delta}* resonances decaying into {delta}(1232){pi}, N({pi}{pi}){sub S}, N(1440)P{sub 11}{pi}, and N(1520)D{sub 13}{pi} are determined in a partial wave analysis of this data and of data from other reactions. Several partial decay widths were not known before. Interesting decay patterns are observed which are not even qualitatively reproduced by quark model calculations. In the second resonance region, decays into {delta}(1232){pi} dominate clearly. The N({pi}{pi}){sub S}-wave provides a significant contribution to the cross section, especially in the third resonance region. The P{sub 13}(1720) properties found here are at clear variance to PDG values.

Variation in leaf water delta D and delta 18O values during the evapotranspiration process

International Nuclear Information System (INIS)

Leopoldo, P.R.; Foloni, L.L.

1984-01-01

A theoretical model was developed to evaluate leaf water delta D and delta 18 O variation in relation to: leaf temperature, relative humidity converted to leaf temperature and delta D and delta 18 O values of atmospheric water vapour and soil water. (M.A.C.) [pt

Nitrogen content and delta N-15 of marine algae and associated waters of Maui, Hawaii, from 2012-07-28 to 2014-04-01 (NCEI Accession 0156294)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set includes nutrient data related to algal and water samples collected between 2012 and 2014 on Maui, Hawaii. Algal tissue N%, C:N ratios, and delta N-15...

Investigations of (Delta)14C, (delta)13C, and (delta)15N in vertebrae of white shark (Carcharodon carcharias) from the eastern North Pacific Ocean

Energy Technology Data Exchange (ETDEWEB)

Kerr, L A; Andrews, A H; Cailliet, G M; Brown, T A; Coale, K H

2006-06-08

The white shark (Carcharodon carcharias) has a complex life history that is characterized by large scale movements and a highly variable diet. Estimates of age and growth for the white shark from the eastern North Pacific Ocean indicate they have a slow growth rate and a relatively high longevity. Age, growth, and longevity estimates useful for stock assessment and fishery models, however, require some form of validation. By counting vertebral growth band pairs, ages can be estimated, but because not all sharks deposit annual growth bands and many are not easily discernable, it is necessary to validate growth band periodicity with an independent method. Radiocarbon ({sup 14}C) age validation uses the discrete {sup 14}C signal produced from thermonuclear testing in the 1950s and 1960s that is retained in skeletal structures as a time-specific marker. Growth band pairs in vertebrae, estimated as annual and spanning the 1930s to 1990s, were analyzed for {Delta}{sup 14}C and stable carbon and nitrogen isotopes ({delta}{sup 13}C and {delta}{sup 15}N). The aim of this study was to evaluate the utility of {sup 14}C age validation for a wide-ranging species with a complex life history and to use stable isotope measurements in vertebrae as a means of resolving complexity introduced into the {sup 14}C chronology by ontogenetic shifts in diet and habitat. Stable isotopes provided useful trophic position information; however, validation of age estimates was confounded by what may have been some combination of the dietary source of carbon to the vertebrae, large-scale movement patterns, and steep {sup 14}C gradients with depth in the eastern North Pacific Ocean.

Paleoenvironmental implications of taxonomic variation among δ 15 N values of chloropigments

Science.gov (United States)

Higgins, Meytal B.; Wolfe-Simon, Felisa; Robinson, Rebecca S.; Qin, Yelun; Saito, Mak A.; Pearson, Ann

2011-11-01

Natural variations in the ratios of nitrogen isotopes in biomass reflect variations in nutrient sources utilized for growth. In order to use δ 15N values of chloropigments of photosynthetic organisms to determine the corresponding δ 15N values of biomass - and by extension, surface waters - the isotopic offset between chlorophyll and biomass must be constrained. Here we examine this offset in various geologically-relevant taxa, grown using nutrient sources that may approximate ocean conditions at different times in Earth's history. Phytoplankton in this study include cyanobacteria (diazotrophic and non-diazotrophic), eukaryotic algae (red and green), and anoxygenic photosynthetic bacteria (Proteobacteria), as well as environmental samples from sulfidic lake water. Cultures were grown using N 2, NO 3-, and NH 4+ as nitrogen sources, and were examined under different light regimes and growth conditions. We find surprisingly high variability in the isotopic difference (δ 15N biomass - δ 15N chloropigment) for prokaryotes, with average values for species ranging from -12.2‰ to +11.7‰. We define this difference as ɛpor, a term that encompasses diagenetic porphyrins and chlorins, as well as chlorophyll. Negative values of ɛpor reflect chloropigments that are 15N-enriched relative to biomass. Notably, this enrichment appears to occur only in cyanobacteria. The average value of ɛpor for freshwater cyanobacterial species is -9.8 ± 1.8‰, while for marine cyanobacteria it is -0.9 ± 1.3‰. These isotopic effects group environmentally but not phylogenetically, e.g., ɛpor values for freshwater Chroococcales resemble those of freshwater Nostocales but differ from those of marine Chroococcales. Our measured values of ɛpor for eukaryotic algae (range = 4.7-8.7‰) are similar to previous reports for pure cultures. For all taxa studied, values of ɛpor do not depend on the type of nitrogen substrate used for growth. The observed environmental control of �

Natural 15N abundance of soil N pools and N2O reflect the nitrogen dynamics of forest soils

DEFF Research Database (Denmark)

Pörtl, K.; Zechmeister-Boltenstern, S.; Wanek, W.

2007-01-01

Natural N-15 abundance measurements of ecosystem nitrogen (N) pools and N-15 pool dilution assays of gross N transformation rates were applied to investigate the potential of delta N-15 signatures of soil N pools to reflect the dynamics in the forest soil N cycle. Intact soil cores were collected...

Sediment features, macrozoobenthic assemblages and trophic relationships ({delta}{sup 13}C and {delta}{sup 15}N analysis) following a dystrophic event with anoxia and sulphide development in the Santa Giusta lagoon (western Sardinia, Italy)

Energy Technology Data Exchange (ETDEWEB)

Magni, P. [CNR-IAMC National Research Council - Institute for Coastal Marine Environment c/o IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy); IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy)], E-mail: paolo.magni@iamc.cnr.it; Rajagopal, S. [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); Velde, G. van der [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); National Museum of Natural History Naturalis, P.O. Box 9517, 2300 RA Leiden (Netherlands); Fenzi, G. [IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy); Kassenberg, J. [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); Vizzini, S.; Mazzola, A. [Dipartimento di Biologia Animale, Universita di Palermo, via Archirafi 18, 90123 Palermo (Italy); Giordani, G. [Dipartimento di Scienze Ambientali, Universita di Parma, Via Usberti 33/A, 43100 Parma (Italy)

2008-07-01

Macrozoobenthic assemblages and stable carbon ({delta}{sup 13}C) and nitrogen ({delta}{sup 15}N) isotope values of various primary producers (macroalgae and angiosperms) and consumers (macroinvertebrate filter/suspension feeders, deposit feeders, detritivores/omnivores and carnivores and fishes) were studied in the Santa Giusta lagoon (Sardinia, Italy) before (spring) and after (autumn) a dystrophic event which occurred in the summer of 2004. A few days after the dystrophy, the physico-chemical characteristics of sediments and macrozoobenthic assemblages were also investigated. In the latter occasion, high total organic carbon (3.9%) and organic matter (15.9%) contents of surface sediments went together with peaks in acid-volatile sulphide concentrations. Certain immediate effects were quite extreme, such as the drastic reduction in macrozoobenthos and the massive fish kill in August 2004. Among the macrozoobenthos, there were few individuals of chironomid larvae and Capitella cf. capitata left. However, by October, chironomid larvae were numerous, indicating a lack of predators (e.g. fish) and competitors. In addition, some bivalve species and polychaetes which were absent, or present in small numbers before the event, became relatively numerous. The results are discussed based on a knowledge of the sulphide tolerance of these species. Stable isotope analysis clearly showed that the basal level of the food web for most consumers consisted mainly of macroalgae and sedimentary organic matter, and that the values before and after the dystrophic event were not significantly different from one another. This indicates that the relations among different trophic levels were quickly restored following the dystrophic event.

Evaluation for dinitrogen fixation of alfalfa in field based on δ15N value

International Nuclear Information System (INIS)

Yao Yunyin; Chen Ming; Zhang Xizhong

1992-12-01

The dinitrogen fixation rate of alfalfa was estimated grown in pot and field experiments. β values (isotope fraction factor) of 7 cultivars of alfalfa (Medicago sativa L.) and white clover (Trifolium repens L.) grown in N-free liquid culture medium were examined. Variations in the δ 15 N values of varieties of alfalfa at growing seasons and forage grasses grown under various conditions were measured. %Ndfa of alfalfa was estimated using the natural 15 N abundance method, 15 N isotope dilution method and total N difference, and their accuracy was compared

Use of stable nitrogen isotope signatures of riparian macrophytes as an indicator of anthropogenic N inputs to river ecosystems.

Science.gov (United States)

Kohzu, Ayato; Miyajima, Toshihiro; Tayasu, Ichiro; Yoshimizu, Chikage; Hyodo, Fujio; Matsui, Kiyoshi; Nakano, Takanori; Wada, Eitaro; Fujita, Noboru; Nagata, Toshi

2008-11-01

Deterioration of aquatic ecosystems resulting from enhanced anthropogenic N loading has become an issue of increasing concern worldwide, and methods are needed to trace sources of N in rivers. Because nitrate from sewage is enriched in 15N relative to nitrate from natural soils, delta(15)N values of stream nitrate (delta(15)Nnitrate) should be an appropriate index of anthropogenic N loading to rivers, as should the delta(15)N values of riparian plants (delta(15)Nplant) because they are consumers of nitrate. We determined the delta(15)N values of stream nitrate and six species of riparian macrophytes in 31 rivers in the Lake Biwa Basin in Japan. We then tested the correlation between these values and various land-use parameters, including the percentage of land used for residential and agricultural purposes as well as for natural areas. These delta(15)N values were significantly positively correlated with land use (%) that had a high N load (i.e., residential or agricultural use) and significantly negatively correlated with forest (%). These findings indicate that delta(15)N values of stream nitrate and riparian plants might be good indicators of anthropogenic inputs of nitrogen.

Diet-tissue stable isotope (delta¹³C and delta¹⁵N) discrimination factors for multiple tissues from terrestrial reptiles (rock iguanas, Cyclura species)

OpenAIRE

Steinitz, Ronnie

2015-01-01

Trophic interactions can drive community structure; therefore, studying food webs is key in understanding ecological communities. Stable isotope analysis is a powerful tool for reconstructing foraging patterns. However, stable isotope discrimination factors (delta¹³C and delta¹⁵N) are needed to best use this tool. We determined the first delta¹³C and delta¹⁵N values for Rock Iguanas (Cyclura spp.) to better understand isotope fractionation patterns in reptiles and estimate wild reptile diets....

Paleoenvironmental implications of taxonomic variation among δ15N values of chloropigments

Science.gov (United States)

Higgins, Meytal B.; Wolfe-Simon, Felisa; Robinson, Rebecca S.; Qin, Yelun; Saito, Mark A.; Pearson, Ann

2011-01-01

Natural variations in the ratios of nitrogen isotopes in biomass reflect variations in nutrient sources utilized for growth. In order to use δ15N values of chloropigments of photosynthetic organisms to determine the corresponding δ15N values of biomass – and by extension, surface waters – the isotopic offset between chlorophyll and biomass must be constrained. Here we examine this offset in various geologically-relevant taxa, grown using nutrient sources that may approximate ocean conditions at different times in Earth’s history. Phytoplankton in this study include cyanobacteria (diazotrophic and non-diazotrophic), eukaryotic algae (red and green), and anoxygenic photosynthetic bacteria (Proteobacteria), as well as environmental samples from sulfidic lake water. Cultures were grown using N2, NO3−, and NH4+ as nitrogen sources, and were examined under different light regimes and growth conditions. We find surprisingly high variability in the isotopic difference (δ15Nbiomass − δ15Nchloropigment) for prokaryotes, with average values for species ranging from −12.2‰ to +11.7‰. We define this difference as εpor, a term that encompasses diagenetic porphyrins and chlorins, as well as chlorophyll. Negative values of εpor reflect chloropigments that are 15N-enriched relative to biomass. Notably, this enrichment appears to occur only in cyanobacteria. The average value of εpor for freshwater cyanobacterial species is −9.8 ± 1.8‰, while for marine cyanobacteria it is −0.9 ± 1.3‰. These isotopic effects group environmentally but not phylogenetically, e.g., εpor values for freshwater Chroococcales resemble those of freshwater Nostocales but differ from those of marine Chroococcales. Our measured values of εpor for eukaryotic algae (range = 4.7–8.7‰) are similar to previous reports for pure cultures. For all taxa studied, values of εpor do not depend on the type of nitrogen substrate used for growth. The observed

δ15N values of atmospheric N species simultaneously collected using sector-based samplers distant from sources - Isotopic inheritance and fractionation

Science.gov (United States)

Savard, Martine M.; Cole, Amanda; Smirnoff, Anna; Vet, Robert

2017-08-01

The nitrogen isotope ratios (δ15N) of atmospheric N species are commonly suggested as indicators of N emission sources. Therefore, numerous research studies have developed analytical methodologies and characterized primary (gases) and secondary emission products (mostly precipitation and aerosols) from various emitters. These previous studies have generally collected either reduced or oxidized N forms, and sampled them separately prior to determining their δ15N values. Distinctive isotopic signals have been reported for emissions from various sources, and seasonality of the δ15N values has been frequently attributed to shifts in relative contributions from sources with different isotopic signals. However, theoretical concepts suggest that temperature effects on isotopic fractionation may also affect the δ15N values of atmospheric reaction products. Here we use a sector-based multi-stage filter system to simultaneously collect seven reduced and oxidized N species downwind from five different source types in Alberta, Canada. We report δ15N values obtained with a state-of-the-art gold-furnace pre-concentrator online with an isotope ratio mass spectrometer (IRMS) to provide representative results even for oxidized-N forms. We find that equilibrium isotope effects and their temperature dependence play significant roles in determining the δ15N values of the secondary emission products. In the end, seasonal δ15N changes here are mainly caused by temperature effects on fractionation, and the δ15N values of only two N species from one source type can be retained as potential fingerprints of emissions.

Yields, market values and n use efficiency (15n) in flue-cured tobacco influenced by basal fertilization time and n fertilizer

International Nuclear Information System (INIS)

Xie Zhijian; Tu Shuxin; Li Jinping; Chen Zhenguo; Xu Rubing; Cao Shiming; Li Jianping; Wang Xuelong; Chen Liangcun; Guo Li; Cao Xianglian; Hu Gongjun; Zhang Yunzheng

2010-01-01

A field experiment with 15 N isotope tracing micro-plots was carried out to study the effects of basal N fertilizer application time (0 d, 15 d, 30 d before the transplanting) on the yields, market values and N uptake, utilization and distribution in different organs of flue-cured tobacco (FCT) in two ecological tobacco production areas Zhaojiashan (N 31 degree 28', E 111 degree 15', 903 m above sea level) and Laowan (N 31 degree 27', E 111 degree 14', 1 130 m above sea level)] of Xiangfan city, Hubei province. The results showed that supplying N fertilizer significantly increased the yields and market values of FCT by 13%-40% and 14%-35% for the experimental site of Zhaojiashan (lower altitude ) and Laowan (higher altitude), respectively. Compared to applying basal fertilizer at 0 d before transplanting, applying basal fertilizer at 15-30 d before transplanting increased the market values by 10%-30% (P<0.05). And early application of basal N fertilizer (30 d before transplanting) increased N accumulation by 8%-26% as compared with that of applying basal N fertilizer at 0 d or 15 d before transplanting in the two ecological areas. There was no significant effects of basal N application time on N fertilizer efficiency in lower altitude site, but increasing by 3%-6% in higher altitude site. The proportion of fertilizer N to total N in FCT decreased by 8%-32% in lower altitude, but increased by 25%-32% in higher altitude when basal N fertilizer was supplied at 30d before transplanting., These results indicated that properly earlier supplication of basal N fertilizer could improve the N fertilizer efficiency, and thus increase the yields and market values of FCT, especially in higher altitude areas with less sunshine and lower temperature. (authors)

Displacement waves in La2CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta)

Science.gov (United States)

Kajitani, Tsuyoshi; Onozuka, Takashi; Yamaguchi, Yasuo; Hirabayashi, Makoto; Syono, Yasuhiko

1987-11-01

Structural investigation of orthorhombic La2CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta) was carried out by means of X-ray and neutron diffraction on the basis of the space group Cmmm. The periodic expansion/contraction type distortion of CuO6 octahedra was found in both orthorhombic compounds. The distortion is nearly one-dimensional in La2CuO(4-delta) but is two-dimensional in La(1.85)Sr(0.15)CuO(4-delta). The existence of a charge-density wave is highly possible in the structures.

Displacement waves in La/sub 2/CuO(4-delta) and La(1. 85)Sr(0. 15)CuO(4-delta)

Energy Technology Data Exchange (ETDEWEB)

Kajitani, T.; Onozuka, T.; Yamaguchi, Y.; Hirabayashi, M.; Syono, Y.

1987-11-01

Structural investigation of orthorhombic La/sub 2/CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta) was carried out by means of X-ray and neutron diffraction on the basis of the space group Cmmm. The periodic expansion/contraction type distortion of CuO6 octahedra was found in both orthorhombic compounds. The distortion is nearly one-dimensional in La/sub 2/CuO(4-delta) but is two-dimensional in La(1.85)Sr(0.15)CuO(4-delta). The existence of a charge-density wave is highly possible in the structures. 20 references.

Analysis of historical delta values for IAEA/LANL NDA training courses

International Nuclear Information System (INIS)

Geist, William; Santi, Peter; Swinhoe, Martyn; Bonner, Elisa

2009-01-01

The Los Alamos National Laboratory (LANL) supports the International Atomic Energy Agency (IAEA) by providing training for IAEA inspectors in neutron and gamma-ray Nondestructive Assay (NDA) of nuclear material. Since 1980, all new IAEA inspectors attend this two week course at LANL gaining hands-on experience in the application of NDA techniques, procedures and analysis to measure plutonium and uranium nuclear material standards with well known pedigrees. As part of the course the inspectors conduct an inventory verification exercise. This exercise provides inspectors the opportunity to test their abilities in performing verification measurements using the various NDA techniques. For an inspector, the verification of an item is nominally based on whether the measured assay value agrees with the declared value to within three times the historical delta value. The historical delta value represents the average difference between measured and declared values from previous measurements taken on similar material with the same measurement technology. If the measurement falls outside a limit of three times the historical delta value, the declaration is not verified. This paper uses measurement data from five years of IAEA courses to calculate a historical delta for five non-destructive assay methods: Gamma-ray Enrichment, Gamma-ray Plutonium Isotopics, Passive Neutron Coincidence Counting, Active Neutron Coincidence Counting and the Neutron Coincidence Collar. These historical deltas provide information as to the precision and accuracy of these measurement techniques under realistic conditions.

Macroalgae δ15N values in well-mixed estuaries: Indicator of anthropogenic nitrogen input or macroalgae metabolism?

Science.gov (United States)

Raimonet, Mélanie; Guillou, Gaël; Mornet, Françoise; Richard, Pierre

2013-03-01

Although nitrogen stable isotope ratio (δ15N) in macroalgae is widely used as a bioindicator of anthropogenic nitrogen inputs to the coastal zone, recent studies suggest the possible role of macroalgae metabolism in δ15N variability. Simultaneous determinations of δ15N of dissolved inorganic nitrogen (DIN) along the land-sea continuum, inter-species variability of δ15N and its sensitivity to environmental factors are necessary to confirm the efficiency of macroalgae δ15N in monitoring nitrogen origin in mixed-use watersheds. In this study, δ15N of annual and perennial macroalgae (Ulva sp., Enteromorpha sp., Fucus vesiculosus and Fucus serratus) are compared to δ15N-DIN along the Charente Estuary, after characterizing δ15N of the three main DIN sources (i.e. cultivated area, pasture, sewage treatment plant outlet). During late winter and spring, when human activities produce high DIN inputs, DIN sources exhibit distinct δ15N signals in nitrate (NO) and ammonium (NH): cultivated area (+6.5 ± 0.6‰ and +9.0 ± 11.0‰), pasture (+9.2 ± 1.8‰ and +12.4‰) and sewage treatment plant discharge (+16.9 ± 8.7‰ and +25.4 ± 5.9‰). While sources show distinct δN- in this multiple source catchment, the overall mixture of NO sources - generally >95% DIN - leads to low variations of δN-NO at the mouth of the estuary (+7.7 to +8.4‰). Even if estuarine δN-NO values are not significantly different from pristine continental and oceanic site (+7.3‰ and +7.4‰), macroalgae δ15N values are generally higher at the mouth of the estuary. This highlights high anthropogenic DIN inputs in the estuary, and enhanced contribution of 15N-depleted NH in oceanic waters. Although seasonal variations in δN-NO are low, the same temporal trends in macroalgae δ15N values at estuarine and oceanic sites, and inter-species differences in δ15N values, suggest that macroalgae δ15N values might be modified by the metabolic response of macroalgae to environmental parameters (e

Natural abundances of /sup 15/N as a source indicator for near-shore marine sedimentary and dissolved nitrogen

Energy Technology Data Exchange (ETDEWEB)

Sweeney, R E; Kaplan, I R [California Univ., Los Angeles (USA). Inst. of Geophysics and Planetary Physics

1980-04-01

The nitrogen isotope ratios of 42 sediment samples of total nitrogen and 38 dissolved pore-water ammonium samples from Santa Barbara Basin sediment cores were measured. The range of delta/sup 15/N values for total nitrogen was +2.89 to +9.4 per thousand with a mean of +6.8 per thousand and for pore water ammonium, +8.2 to +12.4 per thousand with a mean of 10.2 per thousand. The results suggest that the dissolved ammonium in the pore water is produced from bacterial degradation of marine organic matter. The range of delta /sup 15/N values for total nitrogen in the sediment is interpreted as resulting from an admixture of nitrogen derived from marine (+10 per thousand) and terrestrial (+2 per thousand) cores. The marine component of this mixture, composed principally of calcium carbonate with smaller amounts of opal and organic matter, contains approximately 1.0% nitrogen. The terrestrial component, which comprises over 80% of the sediment, contains approximately 0.1% organically bound nitrogen and accounts for > 25% of the total nitrogen in Santa Barbara Basin sediment.

Enthalpy of dilution and volumetric properties of N-glycylglycine in aqueous xylitol solutions at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Liu Min, E-mail: panpanliumin@163.co [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Wang Lili; Li Guangqian; Dong Lina; Sun Dezhi [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Zhu Lanying [College of Life Science and Bioengineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Di Youying [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China)

2011-06-15

Highlights: Enthalpies of dilution of N-glycylglycine in aqueous xylitol solutions were determined at 298.15 K. The homogeneous enthalpic interaction coefficients were calculated. Apparent molar volumes of the ternary systems were calculated from the data of densities. Limiting partial molar volumes and limiting partial molar volumes of transfer were deduced. - Abstract: The enthalpy of dilution of N-glycylglycine ({Delta}{sub dil}H{sub m}) in aqueous xylitol solutions has been determined by means of flow-mix isothermal microcalorimetry at the temperature of 298.15 K. The homogeneous enthalpic interaction coefficients (h{sub 2}, h{sub 3}, and h{sub 4}) which characterize the interactions of examined N-glycylglycine in aqueous xylitol solutions have been calculated according to the excess enthalpy concept based on the values of dilution enthalpy. It has been found that the enthalpic pair interaction coefficients (h{sub 2}) in the systems investigated are negative and become less negative as the molality of xylitol increases. Values of the density ({rho}) of the ternary homogeneous systems were also measured with a quartz vibrating-tube densimeter at the temperature of 298.15 K. The values of the apparent molar volume (V{sub {phi}}) of the ternary systems were calculated from the data of density, which have been used to deduce limiting partial molar volumes of N-glycylglycine (V{sub {phi}}{sup o}) and limiting partial molar volumes of transfer ({Delta}{sub trs}V{sub {phi}}{sup o}) from water to aqueous xylitol solutions at different concentrations. The results have been discussed based on solute-solute interactions and solvation effects.

[Simultaneous determination of delta13C values of glycerol and ethanol in wine by liquid chromatography coupled with isotope ratio mass spectrometry].

Science.gov (United States)

Li, Xuemin; Jia, Guangqun; Cao, Yanzhong; Zhang, Jinjie; Wang, Lei; Sun, Huiyuan

2013-12-01

A novel procedure was established for the characterization of delta13C values of glycerol and ethanol in wine by liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). Several parameters influencing the separation of glycerol and ethanol from wine matrix were optimized. The precision and accuracy of the proposed method were 0.15 per thousand to 0.26 per thousand and 0.11 per thousand to 0.28 per thousand, respectively. The results obtained for 40 wine samples displayed that the delta13C value of glycerol ranged from--26.87 per thousand to--32.96 per thousand and that of ethanol ranged from--24.06 per thousand to--28.29 per thousand. Close correlations (R = 0.82) were obtained between the delta13C values of glycerol and ethanol. The proposed method didn't need complex sample treatment, and the delta13C values of glycerol and ethanol in wine can be simultaneously determined, thus improving the method in terms of simplicity and speed compared with traditional methods.

Use of N stable isotope and microbial analyses to define wastewater influence in Mobile Bay, AL.

Science.gov (United States)

Daskin, Joshua H; Calci, Kevin R; Burkhardt, William; Carmichael, Ruth H

2008-05-01

We assessed short-term ecological and potential human health effects of wastewater treatment plant (WTP) effluent by measuring delta 15N per thousand and microbial concentrations in oysters and suspended particulate matter (SPM). We also tested male-specific bacteriophage (MSB) as an alternative to fecal coliforms, to assess potential influence of wastewater contamination on shellfish. WTP effluent did not affect oyster growth or survival, but SPM and oysters acquired wastewater-specific delta 15N per thousand. delta 15N values were depleted near the WTP, typical of low-level processed wastewater. Fecal coliform and MSB concentrations were higher in samples taken closest to the WTP, and MSB values were significantly correlated with delta 15N per thousand in oyster tissues. Overall, oysters demonstrated relatively rapid integration and accumulation of wastewater-specific delta 15N per thousand and indicator microorganisms compared to water samples. These data suggest oysters were superior sentinels compared to water, and MSB was a more reliable indicator of wastewater influence on shellfish than fecal coliforms.

Use of N stable isotope and microbial analyses to define wastewater influence in Mobile Bay, AL

Energy Technology Data Exchange (ETDEWEB)

Daskin, Joshua H. [MB 0193 Brandeis University, Waltham, MA 02454 (United States); Calci, Kevin R.; Burkhardt, William [1 Iberville Road, US Food and Drug Administration Gulf Coast Seafood Laboratory, Dauphin Island, AL 36528 (United States); Carmichael, Ruth H. [101 Bienville Boulevard, Dauphin Island Sea Lab, Dauphin Island, AL 36528 (United States); University of South Alabama, Mobile, AL, 36688 (United States)], E-mail: rcarmichael@disl.org

2008-05-15

We assessed short-term ecological and potential human health effects of wastewater treatment plant (WTP) effluent by measuring {delta}{sup 15}N per mille and microbial concentrations in oysters and suspended particulate matter (SPM). We also tested male-specific bacteriophage (MSB) as an alternative to fecal coliforms, to assess potential influence of wastewater contamination on shellfish. WTP effluent did not affect oyster growth or survival, but SPM and oysters acquired wastewater-specific {delta}{sup 15}N per mille . {delta}{sup 15}N values were depleted near the WTP, typical of low-level processed wastewater. Fecal coliform and MSB concentrations were higher in samples taken closest to the WTP, and MSB values were significantly correlated with {delta}{sup 15}N per mille in oyster tissues. Overall, oysters demonstrated relatively rapid integration and accumulation of wastewater-specific {delta}{sup 15}N per mille and indicator microorganisms compared to water samples. These data suggest oysters were superior sentinels compared to water, and MSB was a more reliable indicator of wastewater influence on shellfish than fecal coliforms.

Rapid agonist-induced loss of sup 125 I-. beta. -endorphin opioid receptor sites in NG108-15, but not SK-N-SH neuroblastoma cells

Energy Technology Data Exchange (ETDEWEB)

Cone, R.I.; Lameh, J.; Sadee, W. (Univ. of California, San Francisco (United States))

1991-01-01

The authors have measured {mu} and {delta} opioid receptor sites on intact SK-N-SH and NG108-15 neuroblastoma cells, respectively, in culture. Use of {sup 125}I-{beta}-endorphin ({beta}E) as a tracer, together with {beta}E(6-31) to block high-affinity non-opioid binding in both cell lines, permitted the measurement of cell surface {mu} and {delta} opioid receptor sites. Labeling was at {delta} sites in NG108-15 cells and predominantly at {mu} sites in SK-N-SH cells. Pretreatment with the {mu} and {delta} agonist, DADLE, caused a rapid loss of cell surface {delta} receptor sites in NG108-15 cells, but failed to reduce significantly {mu} receptor density in SK-N-SH cells.

Anthropogenic nitrogen input traced by means of δ 15N values in macroalgae: Results from in-situ incubation experiments

International Nuclear Information System (INIS)

Deutsch, Barbara; Voss, Maren

2006-01-01

The macroalgae species Fucus vesiculosus (Phaeophyta), Polysiphonia sp., and Ceramium rubrum (Rhodophyta) originally grown at an unpolluted brackish site of the southern Baltic Sea were incubated for 10 and 14 days at 12 stations along a salinity gradient in a highly polluted estuary. We have expected an adaptation of the initially low δ 15 N values to the higher ones within the incubation period. In addition to the macroalgae the δ 15 N values of NO 3 - were measured to evaluate fractionation processes of the source nitrate. Inside the estuary, δ 15 N-NO 3 - values were 6.2-9.7 per mille , indicating anthropogenic nitrogen sources. The red macroalgae adequately reflected the nitrate isotope values in the surrounding waters, whereas for F. vesiculosus the results were not that clear. The reasons were assumed to be higher initial δ 15 N values of F. vesiculosus and presumably a too slow nitrogen uptake and growth rate. The method of macroalgae incubations seems suitable as a simple monitoring to study the influence of anthropogenic nitrogen loading in an estuarine environment

The dynamics of central Main Ethiopian Rift waters: Evidence from {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr ratios

Energy Technology Data Exchange (ETDEWEB)

Rango, Tewodros, E-mail: tewodros.godebo@duke.edu [Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States)] [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia); Petrini, Riccardo; Stenni, Barbara [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Bianchini, Gianluca [Istituto di Geoscienze e Georisorse-CNR, Pisa (Italy)] [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Slejko, Francesca [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Beccaluva, Luigi [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Ayenew, Tenalem [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia)

2010-12-15

Research highlights: {yields} Chemical and isotope ({delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr) techniques are applied to understand various hydrological processes in the Main Ethiopian Rift. {yields} Some of the studied groundwaters display a depleted {delta}D-{delta}{sup 18}O composition when compared to the present-day average precipitation, thus suggesting that the rift floor aquifers also contains paleo-meteoric waters recharge associated with deep flow system. {yields} The pristine waters coming from the highlands display isotopic compositions characterized by less radiogenic {sup 87}Sr/{sup 86}Sr (and more depleted {delta}D, {delta}{sup 18}O). This isotopic signature subsequently evolves towards higher {sup 87}Sr/{sup 86}Sr by an interaction with the more radiogenic rhyolites of the rift and their weathered and redeposited products. - Abstract: Water samples from cold and geothermal boreholes, hot springs, lakes and rivers were analyzed for {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr compositions in order to investigate lake water-groundwater mixing processes, water-rock interactions, and to evaluate groundwater flow paths in the central Main Ethiopian Rift (MER) of the Ziway-Shala basin. Different ranges of isotopic values were recorded for different water types: hot springs show {delta}{sup 18}O -3.36 to +3.69 and {delta}D -15.85 to +24.23, deep Aluto-Langano geothermal wells show {delta}{sup 18}O -4.65 to -1.24 and {delta}D -12.39 to -9.31, groundwater wells show {delta}{sup 18}O -3.99 to +5.14 and {delta}D -19.69 to +32.27, whereas the lakes show {delta}{sup 18}O and {delta}D in the range +3.98 to +7.92 and +26.19 to +45.71, respectively. The intersection of the Local Meteoric Water Line (LMWL: {delta}D = 7 {delta}{sup 18}O + 11.2, R{sup 2} = 0.94, n = 42) and the Local Evaporation Line (LEL: {delta}D = 5.63{delta}{sup 18}O + 8, n = 14, R{sup 2} = 0.82) was used to estimate the average isotopic composition of recharge water into the

Dermal absorption of the insecticide lindane (1 delta, 2 delta, 3 beta, 4 delta, 5 delta, 6 beta-hexachlorocyclohexane) in rats and rhesus monkeys: Effect of anatomical site

International Nuclear Information System (INIS)

Moody, R.P.; Ritter, L.

1989-01-01

Dermal absorption of the insecticide lindane (1 delta, 2 delta, 3 beta, 4 delta, 5 delta, 6 beta-hexachlorocyclohexane) was determined in rats and rhesus monkeys. Lindane is in widespread use as a 1% cream or lotion scabicide formulation and as a 1% miticide shampoo for body lice control in humans. Results obtained following our in vivo dermal absorption procedure demonstrated that 18 +/- 4.1%, 34 +/- 5.2%, and 54 +/- 26.3% of the applied dose was absorbed following topical applications at a rate of 1.5 micrograms/cm2 (6.2 micrograms/100 microliters of acetone) of the 14C-labeled pesticide to 4.2-cm2 regions of the forearm (n = 8), forehead (n = 7), and palm (n = 4) of rhesus monkeys, respectively. Dose sites were washed with soapy water 24 h posttreatment. Comparative studies in rats (n = 5) dosed middorsally demonstrated 31 +/- 9.5% absorption. Statistical analysis of the 14C excretion kinetics demonstrated slower clearance of lindane from rats than monkey forearm, forehead, or palm. Intramuscular (im) injections of 14C-lindane gave 52 +/- 7.1% recovery in monkey (n = 8) and 64 +/- 5.9% in rats (n = 5), suggesting body storage of this lipophilic chemical

N-Type delta Doping of High-Purity Silicon Imaging Arrays

Science.gov (United States)

Blacksberg, Jordana; Hoenk, Michael; Nikzad, Shouleh

2005-01-01

A process for n-type (electron-donor) delta doping has shown promise as a means of modifying back-illuminated image detectors made from n-doped high-purity silicon to enable them to detect high-energy photons (ultraviolet and x-rays) and low-energy charged particles (electrons and ions). This process is applicable to imaging detectors of several types, including charge-coupled devices, hybrid devices, and complementary metal oxide/semiconductor detector arrays. Delta doping is so named because its density-vs.-depth characteristic is reminiscent of the Dirac delta function (impulse function): the dopant is highly concentrated in a very thin layer. Preferably, the dopant is concentrated in one or at most two atomic layers in a crystal plane and, therefore, delta doping is also known as atomic-plane doping. The use of doping to enable detection of high-energy photons and low-energy particles was reported in several prior NASA Tech Briefs articles. As described in more detail in those articles, the main benefit afforded by delta doping of a back-illuminated silicon detector is to eliminate a "dead" layer at the back surface of the silicon wherein high-energy photons and low-energy particles are absorbed without detection. An additional benefit is that the delta-doped layer can serve as a back-side electrical contact. Delta doping of p-type silicon detectors is well established. The development of the present process addresses concerns specific to the delta doping of high-purity silicon detectors, which are typically n-type. The present process involves relatively low temperatures, is fully compatible with other processes used to fabricate the detectors, and does not entail interruption of those processes. Indeed, this process can be the last stage in the fabrication of an imaging detector that has, in all other respects, already been fully processed, including metallized. This process includes molecular-beam epitaxy (MBE) for deposition of three layers, including

Variation in hair δ13C and δ15N values in long-tailed macaques (Macaca fascicularis) from Singapore

Science.gov (United States)

Schillaci, Michael A.; Castellini, J. Margaret; Stricker, Craig A.; Jones-Engel, Lisa; Lee, Benjamin P.Y.-H.

2014-01-01

Much of the primatology literature on stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) has focused on African and New World species, with comparatively little research published on Asian primates. Here we present hair δ13C and δ15N isotope values for a sample of 33 long-tailed macaques from Singapore. We evaluate the suggestion by a previous researcher that forest degradation and biodiversity loss in Singapore have led to a decline in macaque trophic level. The results of our analysis indicated significant spatial variability in δ13C but not δ15N. The range of variation in δ13C was consistent with a diet based on C3 resources, with one group exhibiting low values consistent with a closed canopy environment. Relative to other macaque species from Europe and Asia, the macaques from Singapore exhibited a low mean δ13C value but mid-range mean δ15N value. Previous research suggesting a decline in macaque trophic level is not supported by the results of our study.

Thermodynamic investigation of methyl salicylate/1-pentanol binary system in the temperature range from 278.15K to 303.15K

Energy Technology Data Exchange (ETDEWEB)

Tsierkezos, Nikos G. [Institut fuer Chemie, Humboldt-Universitaet zu Berlin, Brook-Taylor-Strasse 2, D-12489 Berlin (Germany)]. E-mail: tsierkezos@chemie.hu-berlin.de; Molinou, Ioanna E. [Physical Chemistry Laboratory, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771 (Greece)]. E-mail: imolinou@chem.uoa.gr

2007-08-15

Densities ({rho}), speeds of sound (u), isentropic compressibilities (k{sub s}), refractive indices (n{sub D}), and surface tensions ({sigma}) of binary mixtures of methyl salicylate (MSL) with 1-pentanol (PEN) have been measured over the entire composition range at the temperatures of 278.15K, 288.15K, and 303.15K. The excess molar volumes (V{sup E}), excess surface tensions ({sigma}{sup E}), deviations in speed of sound ({delta}u), deviations in isentropic compressibility ({delta}k{sub s}), and deviations in molar refraction ({delta}R) have been calculated. The excess thermodynamic properties V{sup E}, {sigma}{sup E}, {delta}u, {delta}k{sub s}, and {delta}R were fitted to the Redlich-Kister polynomial equation and the A{sub k} coefficients as well as the standard deviations (d) between the calculated and experimental values have been derived. The surface tension ({sigma}) values have been further used for the calculation of the surface entropy (S{sup S}) and the surface enthalpy (H{sup S}) per unit surface area. The lyophobicity ({beta}) and the surface mole fraction (x{sub 2}{sup S}) of the surfactant component PEN have been also derived using the extended Langmuir model. The results provide information on the molecular interactions between the unlike molecules that take place at the surface and the bulk.

15-Deoxy-delta12,14-prostaglandin J2, a neuroprotectant or a neurotoxicant?

International Nuclear Information System (INIS)

Koh, Seong-Ho; Jung, Boo; Song, Chi Won; Kim, Youngchul; Kim, Yong Soon; Kim, Seung Hyun

2005-01-01

15-Deoxy-delta12,14-prostaglandin J2 (15d-PGJ2) is a potent ligand for peroxisome proliferators-activated receptor γ (PPARγ). However, its various effects independent of PPARγ have recently been observed. The effect of 15d-PGJ2 on neuronal cells is still controversial. We investigated its effect on neuronal cells (N18D3 cells). When N18D3 cells were treated with 15d-PGJ2, the viability was not changed up to 8 μM, but decreased at higher than 8 μM. The expressions of survival signals, such as p85a phosphatidylinositol 3-kinase, phospho-Akt, and phospho-glycogen synthase kinase-3 beta (Ser-9), slightly increased up to 8 μM, however, decreased at higher than 8 μM. The levels of free radicals and membrane lipid peroxidation and the expression of c-Jun N-terminal Kinase increased in a dose-dependent manner, especially at higher than 8 μM. However, the expressions of death signals, such as cytosolic cytochrome c, activated caspase-3, and cleaved poly(ADP-ribose) polymerase, decreased up to 8 μM, however, increased at higher than 8 μM. In the study to evaluate whether low dose of 15d-PGJ2, up to 8 μM, had protective effect on oxidative stress-injured N18D3 cells, compared to the cells treated with only 100 μM H 2 O 2 , the pretreatment with 8 μM 15d-PGJ2 increased the viability and the expressions of the survival signals, but decreased them of the death signals. These results indicate that 15d-PGJ2 could be a neuroprotectant or a neurotoxicant, depending on its concentration. Therefore, some specific optimum dose of 15d-PGJ2 may be a new potential therapeutic candidate for oxidative stress-injury model of neurodegenerative diseases

{sup 37}Cl, {sup 15}N, {sup 13}C isotopic analysis of common agro-chemicals for identifying non-point source agricultural contaminants

Energy Technology Data Exchange (ETDEWEB)

Annable, W.K. [Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)]. E-mail: wkannabl@uwaterloo.ca; Frape, S.K. [Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Shouakar-Stash, O. [Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Shanoff, T. [Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Drimmie, R.J. [Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Harvey, F.E. [School of Natural Resources, University of Nebraska, Lincoln, NE 68588-0517 (United States)

2007-07-15

The isotopic compositions of commercially available herbicides were analyzed to determine their respective {sup 15}N, {sup 13}C and {sup 37}Cl signatures for the purposes of developing a discrete tool for tracing and identifying non-point source contaminants in agricultural watersheds. Findings demonstrate that of the agrochemicals evaluated, chlorine stable isotopes signatures range between {delta}{sup 37}Cl = -4.55 per mille and +3.40 per mille , whereas most naturally occurring chlorine stable isotopes signatures, including those of road salt, sewage sludge and fertilizers, vary in a narrow range about the Standard Mean Ocean Chloride (SMOC) between -2.00 per mille and +1.00 per mille . Nitrogen stable isotope values varied widely from {delta}{sup 15}N = -10.86 per mille to +1.44 per mille and carbon stable isotope analysis gave an observed range between {delta}{sup 13}C = -37.13 per mille and -21.35 per mille for the entire suite of agro-chemicals analyzed. When nitrogen, carbon and chlorine stable isotope analyses were compared in a cross-correlation analysis, statistically independent isotopic signatures exist suggesting a new potential tracer tool for identifying herbicides in the environment.

Utility of Reference Change Values for Delta Check Limits.

Science.gov (United States)

Ko, Dae-Hyun; Park, Hae-Il; Hyun, Jungwon; Kim, Hyun Soo; Park, Min-Jeong; Shin, Dong Hoon

2017-10-01

To assess the utility of reference change values (RCVs) as delta check limits. A total of 1,650,518 paired results for 23 general chemistry test results from June 1, 2014, to October 31, 2016, were analyzed. The RCVs for each analyte were calculated from the analytical imprecision and within-subject biological variation. The percent differences between two consecutive results in one patient were categorized into one of four groups: outpatients, inpatients, emergency care, and general health care. For each, 2.5th and 97.5th percentile values were computed and compared with their RCVs. The distributions were assessed for normality using the Kolmogorov-Smirnov test. Most of the estimated limits were larger than the corresponding RCVs and, furthermore, with notable differences across the groups. Patients in the emergency care group usually demonstrated larger delta percent values than those in the other groups. None of the distributions of the percent differences passed tests of normality when subjected to Kolmogorov-Smirnov analysis. Comparison of estimated RCVs and real-world patient data revealed the pitfalls of applying RCVs in clinical laboratories. Laboratory managers should be aware of the limitations of RCVs and exercise caution when using them. © American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Empirical correlation between protein backbone {sup 15}N and {sup 13}C secondary chemical shifts and its application to nitrogen chemical shift re-referencing

Energy Technology Data Exchange (ETDEWEB)

Wang Liya [Cold Spring Harbor Laboratory (United States); Markley, John L. [University of Wisconsin, Biochemistry Department (United States)], E-mail: markley@nmrfam.wisc.edu

2009-06-15

The linear analysis of chemical shifts (LACS) has provided a robust method for identifying and correcting {sup 13}C chemical shift referencing problems in data from protein NMR spectroscopy. Unlike other approaches, LACS does not require prior knowledge of the three-dimensional structure or inference of the secondary structure of the protein. It also does not require extensive assignment of the NMR data. We report here a way of extending the LACS approach to {sup 15}N NMR data from proteins, so as to enable the detection and correction of inconsistencies in chemical shift referencing for this nucleus. The approach is based on our finding that the secondary {sup 15}N chemical shift of the backbone nitrogen atom of residue i is strongly correlated with the secondary chemical shift difference (experimental minus random coil) between the alpha and beta carbons of residue i - 1. Thus once alpha and beta {sup 13}C chemical shifts are available (their difference is referencing error-free), the {sup 15}N referencing can be validated, and an appropriate offset correction can be derived. This approach can be implemented prior to a structure determination and can be used to analyze potential referencing problems in database data not associated with three-dimensional structure. Application of the LACS algorithm to the current BMRB protein chemical shift database, revealed that nearly 35% of the BMRB entries have {delta}{sup 15}N values mis-referenced by over 0.7 ppm and over 25% of them have {delta}{sup 1}H{sup N} values mis-referenced by over 0.12 ppm. One implication of the findings reported here is that a backbone {sup 15}N chemical shift provides a better indicator of the conformation of the preceding residue than of the residue itself.

Nitrogen isotope variations in camphor (Cinnamomum Camphora) leaves of different ages in upper and lower canopies as an indicator of atmospheric nitrogen sources

Energy Technology Data Exchange (ETDEWEB)

Xiao Huayun, E-mail: xiaohuayun@vip.skleg.c [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, No. 46, Guanshui Road, Guiyang 550002 (China); Wu Lianghong; Zhu Renguo; Wang Yanli; Liu Congqiang [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, No. 46, Guanshui Road, Guiyang 550002 (China)

2011-02-15

Nitrogen isotopic composition of new, middle-aged and old camphor leaves in upper and lower canopies has been determined in a living area, near a motorway and near an industrial area (Jiangan Chemical Fertilizer Plant). We found that at sites near roads, more positive {delta}{sup 15}N values were observed in the camphor leaves, especially in old leaves of upper canopies, and {Delta}{delta}{sup 15}N = {delta}{sup 15}N{sub upper} - {delta}{sup 15}N{sub lower} > 0, while those near the industrial area had more negative {delta}{sup 15}N values and {Delta}{delta}{sup 15}N < 0. These could be explained by two isotopically different atmospheric N sources: greater uptake from isotopically heavy pools of atmospheric NO{sub x} by old leaves in upper canopies at sites adjacent to roads, and greater uptake of {sup 15}N-depleted NH{sub y} in atmospheric deposition by leaves at sites near the industrial area. This study presents novel evidence that {sup 15}N natural abundance of camphor leaves can be used as a robust indicator of atmospheric N sources. - Research highlights: Camphor leaves showed high {delta}{sup 15}N values near roads and low values near the industrial area. The {delta}{sup 15}N values of camphor leaves near roads increased with time of exposure. The {delta}{sup 15}N values of camphor leaves near the industrial area decreased with time of exposure. More positive foliage {delta}{sup 15}N values were found in the upper canopies near roads. Near the industrial area, the upper canopies showed more negative foliage {delta}{sup 15}N values. - Nitrogen isotope in camphor leaves indicating atmospheric nitrogen sources.

Use of low enriched 15N2 for symbiotic fixation tests

International Nuclear Information System (INIS)

Victoria, R.L.

1975-01-01

Gaseous atmospheres containing 15 N 2 with low enrichment were used to test symbiotic nitrogen fixation in beans (Phaseolus vulgari, L.). The tests of fixation in nodulated roots and the tests of fixation in the whole plant, in which the plants were placed inside a specially constructed growth chamber, gave positive results and suggest that the methodology used can be very helpfull in more detailed studies on symbiotic fixation. Samples of atmospheric air were purified by absorption of O 2 and CO 2 by two methods. The purified N 2 obtained was analysed and the results were compared. Samples of bean plant material were collected in natural conditions and analysed for 15 N natural variation. Several samples were prepared for 15 N isotopic analysis by two methods. The results obtained were compared. All samples were analysed in an Atlas-Varian Ch-4 model mass spectrometer, and the results were given in delta 15 N 0 / 00 variation in relation to a standard gas

The gamma N ---> Delta transition in chiral effective-field theory.

Energy Technology Data Exchange (ETDEWEB)

Vladimir Pascalutsa; Marc Vanderhaeghen

2006-04-27

We describe the pion electroproduction processes in the {Delta}(1232)-resonance region within the framework of chiral effective-field theory. By studying the observables of pion electroproduction in a next-to-leading order calculation we are able to make predictions and draw conclusions on the properties of the N {yields} {Delta} electromagnetic form factors.

An automated technique for measuring deltaD and delta18O values of porewater by direct CO2 and H2 equilibration.

Science.gov (United States)

Koehler, G; Wassenaar, L I; Hendry, M J

2000-11-15

The stable-oxygen and -hydrogen isotopic values (deltaD, delta18O) of porewater in geologic media are commonly determined on water obtained by extraction techniques such as centrifugation, mechanical squeezing, vacuum heating and cryogenic microdistillation, and azeotropic distillation. Each of these techniques may cause isotopic fractionation as part the extraction process and each is laborious. Here we demonstrate a new approach to obtain automated, high-precision deltaD and delta18O measurements of porewater in geologic sediments by direct H2- and CO2-porewater equilibration using a modified commercial CO2-water equilibrator. This technique provides an important and cost-effective improvement over current extraction methods, because many samples can be rapidly analyzed with minimal handling, thereby reducing errors and potential for isotopic fractionation. The precision and accuracy of direct H2- and CO2-porewater equilibration is comparable to or better than current porewater extraction methods. Finally, the direct equilibration technique allows investigators to obtain high-resolution (cm scale) porewater deltaD and delta18O profiles using cores from individual boreholes, eliminating the need for costly piezometers or conventional porewater extractions.

Compound-specific nitrogen isotope analysis of D-alanine, L-alanine, and valine: application of diastereomer separation to delta15N and microbial peptidoglycan studies.

Science.gov (United States)

Takano, Yoshinori; Chikaraishi, Yoshito; Ogawa, Nanako O; Kitazato, Hiroshi; Ohkouchi, Naohiko

2009-01-01

We have developed an analytical method to determine the compound-specific nitrogen isotope compositions of individual amino acid enantiomers using gas chromatography/combustion/isotope ratio mass spectrometry. A novel derivatization of amino acid diastereomers by optically active (R)-(-)-2-butanol or (S)-(+)-2-butanol offers two advantages for nitrogen isotope analysis. First, chromatographic chiral separation can be achieved without the use of chiral stationary-phase columns. Second, the elution order of these compounds on the chromatogram can be switched by a designated esterification reaction. We applied the method to the compound-specific nitrogen isotope analysis of D- and L-alanine in a peptidoglycan derived from the cell walls of cultured bacteria (Firmicutes and Actinobacteria; Enterococcus faecalis, Staphylococcus aureus, Staphylococcus staphylolyticus, Lactobacillus acidophilus, Bacillus subtilis, Micrococcus luteus, and Streptomyces sp.), natural whole bacterial cells (Bacillus subtilis var. natto), (pseudo)-peptidoglycan from archaea (Methanobacterium sp.), and cell wall from eukaryota (Saccharomyces cerevisiae). We observed statistically significant differences in nitrogen isotopic compositions; e.g., delta15N ( per thousand vs air) in Staphylococcus staphylolyticus for d-alanine (19.2 +/- 0.5 per thousand, n = 4) and L-alanine (21.3 +/- 0.8 per thousand, n = 4) and in Bacillus subtilis for D-alanine (6.2 +/- 0.2 per thousand, n = 3) and L-alanine (8.2 +/- 0.4 per thousand, n = 3). These results suggest that enzymatic reaction pathways, including the alanine racemase reaction, produce a nitrogen isotopic difference in amino acid enantiomers, resulting in 15N-depleted D-alanine. This method is expected to facilitate compound-specific nitrogen isotope studies of amino acid stereoisomers.

Non-lethal approach identifies variability of δ15N values in the fin rays of Atlantic Goliath Grouper, Epinephelus itajara

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Orian E. Tzadik

2015-06-01

Full Text Available The Atlantic Goliath Grouper, Epinephelus itajara, is critically endangered throughout its range but has begun to show initial signs of recovery in Florida state waters. As the population continues to rebound, researchers face a pressing need to fill the knowledge gaps about this iconic species. Here, we examined the δ15N isotopic records in fin rays collected from Atlantic Goliath Grouper, and related changes of isotopic ratios over time to life history characteristics. Fin-ray analysis was used as a non-lethal technique to sample individuals from two locations at similar latitudes from the west and east coasts of Florida, USA. δ15N data were acquired by mechanically separating the annuli of each fin ray and then analyzing the material in an Irradiance Elemental Analyzer Mass Spectrometer. The δ15N values were consistent among individuals within populations from each coast of Florida, and mirrored the expected changes over the lives of the fish. Overall, differences were found between δ15N values at juvenile life history phases versus adult phases, but the patterns associated with these differences were unique to each coastal group. We demonstrated, for the first time, that δ15N values from fin rays can be used to assess the life histories of Atlantic Goliath Grouper. The non-lethal strategies outlined here can be used to acquire information essential to the management of species of concern, such as those that are threatened or endangered.

Organochlorine pollutants and stable isotopes in resident and migrant passerine birds from northwest Michoacán, Mexico.

Science.gov (United States)

Mora, Miguel A

2008-10-01

Although concentrations of organochlorine compounds (OCs) in birds from most of the United States and Canada have decreased over the last 30 years, there is still concern that migrant birds might be exposed to elevated concentrations of OCs during migration in Latin America. The Lerma-Chapala Basin in west-central Mexico is an important migration corridor and wintering area for many species. The objectives of this study were to assess if resident and migrant birds wintering in western Michoacán, Mexico accumulated elevated concentrations of OCs during fall and spring and to determine if the stable isotopes delta(15)N, delta(13)C, and deltaD could be used to predict burdens and origins of DDE accumulation. Resident and migrant passerine insectivorous birds were collected during fall and spring (2001-2002) in northwest Michoacán, near Chapala Lake, Mexico. The carcasses were analyzed for OCs and tail feathers were analyzed for stable isotopes delta(15)N, delta(13)C, and deltaD. The OCs detected in more than 50% of the samples were: oxychlordane (79%), p,p'-DDE (100%), p,p'-DDT (57%), and total PCBs (100%). p,p'-DDE was the OC detected at the highest concentrations, whereas residues of other OCs were near or below detection limits. Overall, there were no significant differences in concentrations of OCs between seasons or between resident and migrant birds. Concentrations of DDE and oxychlordane were somewhat higher in migrant and resident birds during spring than in fall; however, concentrations were significantly different only for oxychlordane. Two resident birds collected in fall and spring had DDE residues >10 microg/g wet weight in carcass. There were no significant differences in delta(13)C and delta(15)N values among species, between seasons, or between migrant and resident birds. However, deltaD values were clearly different between species and helped differentiate migrant from resident birds. deltaD values also were negatively and significantly correlated

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.

Water and nitrogen conditions affect the relationships of Delta13C and Delta18O to gas exchange and growth in durum wheat.

Science.gov (United States)

Cabrera-Bosquet, Llorenç; Molero, Gemma; Nogués, Salvador; Araus, José Luis

2009-01-01

Whereas the effects of water and nitrogen (N) on plant Delta(13)C have been reported previously, these factors have scarcely been studied for Delta(18)O. Here the combined effect of different water and N regimes on Delta(13)C, Delta(18)O, gas exchange, water-use efficiency (WUE), and growth of four genotypes of durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] cultured in pots was studied. Water and N supply significantly increased plant growth. However, a reduction in water supply did not lead to a significant decrease in gas exchange parameters, and consequently Delta(13)C was only slightly modified by water input. Conversely, N fertilizer significantly decreased Delta(13)C. On the other hand, water supply decreased Delta(18)O values, whereas N did not affect this parameter. Delta(18)O variation was mainly determined by the amount of transpired water throughout plant growth (T(cum)), whereas Delta(13)C variation was explained in part by a combination of leaf N and stomatal conductance (g(s)). Even though the four genotypes showed significant differences in cumulative transpiration rates and biomass, this was not translated into significant differences in Delta(18)O(s). However, genotypic differences in Delta(13)C were observed. Moreover, approximately 80% of the variation in biomass across growing conditions and genotypes was explained by a combination of both isotopes, with Delta(18)O alone accounting for approximately 50%. This illustrates the usefulness of combining Delta(18)O and Delta(13)C in order to assess differences in plant growth and total transpiration, and also to provide a time-integrated record of the photosynthetic and evaporative performance of the plant during the course of crop growth.

Determination of the δ15N of nitrate in water; RSIL lab code 2899

Science.gov (United States)

Coplen, Tyler B.; Qi, Haiping; Revesz, Kinga; Casciotti, Karen; Hannon, Janet E.

2007-01-01

The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 2899 is to determine the δ15N of nitrate (NO3-) in water. The δ15N of the dissolved NO3- is analyzed by conversion of the NO3- to nitrous oxide (N2O), which serves as the analyte for mass spectrometry. A culture of denitrifying bacteria is used in the enzymatic conversion of the NO3- to N2O, which follows the pathway shown in equation 1: NO3- → NO2- → NO → 1/2 N2O (1) Because the bacteria Pseudomonas aureofaciens lack N2O reductive activity, the reaction stops at N2O, unlike the typical denitrification reaction that goes to N2. After several hours, the conversion is complete, and the N2O is extracted from the vial, separated from volatile organic vapor and water vapor by an automated -65 °C isopropanol-slush trap, a Nafion drier, a CO2 and water removal unit (Costech #021020 carbon dioxide absorbent with Mg(ClO4)2), and trapped in a small-volume trap immersed in liquid nitrogen with a modified Finnigan MAT (now Thermo Scientific) GasBench 2 introduction system. After the N2O is released, it is further purified by gas chromatography before introduction to the isotope-ratio mass spectrometer (IRMS). The IRMS is a Thermo Scientific Delta V Plus continuous flow IRMS (CF-IRMS). It has a universal triple collector, consisting of two wide cups with a narrow cup in the middle; it is capable of simultaneously measuring mass/charge (m/z) of the N2O molecule 44, 45, and 46. The ion beams from these m/z values are as follows: m/z = 44 = N2O = 14N14N16O; m/z = 45 = N2O = 14N15N16O or 14N14N17O; m/z = 46 = N2O = 14N14N18O. The 17O contributions to the m/z 44 and m/z 45 ion beams are accounted for before δ15N values are reported.

Ca substitution in RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (R = Y,Er; {delta}<0.15): the influence on the structure and the superconductivity

Energy Technology Data Exchange (ETDEWEB)

Boettger, G.; Fischer, P.; Mesot, J.; Furrer, A.; Zolliker, M.; Fauth, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Kaldis, E. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

1997-09-01

We present a combined neutron and X-ray diffraction study of the structural effects of Ca doping in RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (R = Y,Er; {delta}<0.15). Inelastic neutron scattering has been used to study the low-energy crystal-field (CEF) excitation of Er{sup 3+} in Er{sub 1-x}Ca{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (0{<=}x{<=}0.2). (author) 1 figs., 4 refs.

High-precision measurement of phenylalanine δ15N values for environmental samples: a new approach coupling high-pressure liquid chromatography purification and elemental analyzer isotope ratio mass spectrometry.

Science.gov (United States)

Broek, Taylor A B; Walker, Brett D; Andreasen, Dyke H; McCarthy, Matthew D

2013-11-15

Compound-specific isotope analysis of individual amino acids (CSI-AA) is a powerful new tool for tracing nitrogen (N) source and transformation in biogeochemical cycles. Specifically, the δ(15)N value of phenylalanine (δ(15)N(Phe)) represents an increasingly used proxy for source δ(15)N signatures, with particular promise for paleoceanographic applications. However, current derivatization/gas chromatography methods require expensive and relatively uncommon instrumentation, and have relatively low precision, making many potential applications impractical. A new offline approach has been developed for high-precision δ(15)N measurements of amino acids (δ(15)N(AA)), optimized for δ(15)N(Phe) values. Amino acids (AAs) are first purified via high-pressure liquid chromatography (HPLC), using a mixed-phase column and automated fraction collection. The δ(15)N values are determined via offline elemental analyzer-isotope ratio mass spectrometry (EA-IRMS). The combined HPLC/EA-IRMS method separated most protein AAs with sufficient resolution to obtain accurate δ(15)N values, despite significant intra-peak isotopic fractionation. For δ(15)N(Phe) values, the precision was ±0.16‰ for standards, 4× better than gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS; ±0.64‰). We also compared a δ(15)N(Phe) paleo-record from a deep-sea bamboo coral from Monterey Bay, CA, USA, using our method versus GC/C/IRMS. The two methods produced equivalent δ(15)N(Phe) values within error; however, the δ(15)N(Phe) values from HPLC/EA-IRMS had approximately twice the precision of GC/C/IRMS (average stdev of 0.27‰ ± 0.14‰ vs 0.60‰ ± 0.20‰, respectively). These results demonstrate that offline HPLC represents a viable alternative to traditional GC/C/IMRS for δ(15)N(AA) measurement. HPLC/EA-IRMS is more precise and widely available, and therefore useful in applications requiring increased precision for data interpretation (e.g. δ(15)N paleoproxies

Above room-temperature ferromagnetism of Mn delta-doped GaN nanorods

International Nuclear Information System (INIS)

Lin, Y. T.; Wadekar, P. V.; Kao, H. S.; Chen, T. H.; Chen, Q. Y.; Tu, L. W.; Huang, H. C.; Ho, N. J.

2014-01-01

One-dimensional nitride based diluted magnetic semiconductors were grown by plasma-assisted molecular beam epitaxy. Delta-doping technique was adopted to dope GaN nanorods with Mn. The structural and magnetic properties were investigated. The GaMnN nanorods with a single crystalline structure and with Ga sites substituted by Mn atoms were verified by high-resolution x-ray diffraction and Raman scattering, respectively. Secondary phases were not observed by high-resolution x-ray diffraction and high-resolution transmission electron microscopy. In addition, the magnetic hysteresis curves show that the Mn delta-doped GaN nanorods are ferromagnetic above room temperature. The magnetization with magnetic field perpendicular to GaN c-axis saturates easier than the one with field parallel to GaN c-axis

Flotsam samples can help explain the δ13C and δ15N values of invertebrate resting stages in lake sediment

Science.gov (United States)

van Hardenbroek, Maarten; Rinta, Päivi; Wooller, Matthew J.; Schilder, Jos; Stötter, Tabea; Heiri, Oliver

2018-06-01

The stable isotopic composition of chitinous remains of Cladocera (water fleas) and freshwater Bryozoa (moss animals) preserved in lake sediment records can provide supporting insights into past environmental and ecosystem changes in lakes. Here we explore whether analyses of these remains isolated from lake flotsam can provide information on the driving variables affecting the isotopic composition of these remains. We collected flotsam in 53 lakes and found enough material in 33 lakes to measure the stable carbon and nitrogen isotope ratios (expressed as δ13C and δ15N values, respectively) of resting stages. These values were compared with lake characteristics, water chemistry measurements, and the isotopic composition of sedimentary organic matter (SOM) in the lakes. Mean δ13C values of cladoceran ephippia and SOM were correlated and both were also negatively correlated with deep water methane concentrations and indicators of lake stratification. This supports the findings of previous studies that methane-derived carbon can provide a significant proportion of carbon entering planktonic food webs. Mean δ15N values of bryozoan statoblasts and SOM were correlated, suggesting that both reflect the δ15N values of phytoplankton. Our results provide information on how environmental variables in lakes can influence the δ13C and δ15N values in resting stages, but flotsam samples can also potentially be used to assess seasonal stable isotope variability of resting stages. Both types of information are important to improve palaeoenvironmental interpretations of stable isotope records based on these remains in lake sediments.

Compound-specific δ15N amino acid measurements in littoral mussels in the California upwelling ecosystem: a new approach to generating baseline δ15N Isoscapes for coastal ecosystems.

Directory of Open Access Journals (Sweden)

Natasha L Vokhshoori

Full Text Available We explored δ(15N compound-specific amino acid isotope data (CSI-AA in filter-feeding intertidal mussels (Mytilus californianus as a new approach to construct integrated isoscapes of coastal primary production. We examined spatial δ(15N gradients in the California Upwelling Ecosystem (CUE, determining bulk δ(15N values of mussel tissue from 28 sites between Port Orford, Oregon and La Jolla, California, and applying CSI-AA at selected sites to decouple trophic effects from isotopic values at the base of the food web. Bulk δ(15N values showed a strong linear trend with latitude, increasing from North to South (from ∼ 7‰ to ∼ 12‰, R(2 = 0.759. In contrast, CSI-AA trophic position estimates showed no correlation with latitude. The δ(15N trend is therefore most consistent with a baseline δ(15N gradient, likely due to the mixing of two source waters: low δ(15N nitrate from the southward flowing surface California Current, and the northward transport of the California Undercurrent (CUC, with (15N-enriched nitrate. This interpretation is strongly supported by a similar linear gradient in δ(15N values of phenylalanine (δ(15NPhe, the best AA proxy for baseline δ(15N values. We hypothesize δ(15N(Phe values in intertidal mussels can approximate annual integrated δ(15N values of coastal phytoplankton primary production. We therefore used δ(15N(Phe values to generate the first compound-specific nitrogen isoscape for the coastal Northeast Pacific, which indicates a remarkably linear gradient in coastal primary production δ(15N values. We propose that δ(15N(Phe isoscapes derived from filter feeders can directly characterize baseline δ(15N values across major biochemical provinces, with potential applications for understanding migratory and feeding patterns of top predators, monitoring effects of climate change, and study of paleo- archives.

Losses of Sacramento River Chinook Salmon and Delta Smelt to Entrainment in Water Diversions in the Sacramento–San Joaquin Delta

Directory of Open Access Journals (Sweden)

Wim J. Kimmerer

2008-06-01

Full Text Available Pumping at the water export facilities in the southern Sacramento-San Joaquin Delta kills fish at and near the associated fish-salvage facilities. Correlative analyses of salvage counts with population indices have failed to provide quantitative estimates of the magnitude of this mortality. I estimated the proportional losses of Sacramento River Chinook salmon (Oncorhynchus tshawytscha and delta smelt (Hypomesus transpacificus to place these losses in a population context. The estimate for salmon was based on recoveries of tagged smolts released in the upper Sacramento River basin, and recovered at the fish-salvage facilities in the south Delta and in a trawling program in the western Delta. The proportion of fish salvaged increased with export flow, with a mean value around 10% at the highest export flows recorded. Mortality was around 10% if pre-salvage losses were about 80%, but this value is nearly unconstrained. Losses of adult delta smelt in winter and young delta smelt in spring were estimated from salvage data (adults corrected for estimated pre-salvage survival, or from trawl data in the southern Delta (young. These losses were divided by population size and accumulated over the respective seasons. Losses of adult delta smelt were 1–50% (median 15% although the highest value may have been biased upward. Daily losses of larvae and juveniles were 0–8%, and seasonal losses accumulated were 0–25% (median 13%. The effect of these losses on population abundance was obscured by subsequent 50-fold variability in survival from summer to fall.

Investigation into endogenous N metabolism in /sup 15/N-labelled pigs. 1. /sup 15/N labelling and /sup 15/N excretion in urine and feces after feeding 4 different diets

Energy Technology Data Exchange (ETDEWEB)

Bergner, H; Bergner, U; Adam, K [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin

1984-07-01

4 male castrated pigs (55-65 kg) either received a wheat-fish meal diet (1 and 2) or a wheat-horse bean diet (3 and 4) without straw meal supplement (1 and 3) or with a supplement of 20% dry matter (2 and 4). In order to investigate whether a /sup 15/N labelling of the pigs is also possible with a protein excess in the ration, the animals received 24.8 g (1 and 2) and 11.6 g crude protein/kg/sup 0.75/ live weight (3 and 4). During a 10-day /sup 15/N-labelling 385 mg /sup 15/N excess (/sup 15/N') per kg/sup 0.75/ were applied with /sup 15/N labelling the following quotas of the applied /sup 15/N amount were incorporated: 1 = 10.2%, 2 = 7.2%, 3 = 18.7%, 4 = 14.4%. /sup 15/N excretion in both TCA fractions of feces showed a highly significant positive correlation to the increasing content of crude fibre in the 4 diets. The immediate /sup 15/N incorporation into the TCA-precipitable fraction of feces proves that /sup 15/N enters the large intestine endogenously and serves bacterial protein synthesis. 3 days after the last /sup 15/N application the pigs were killed. The values of atom-% /sup 15/N' were determined in the TCA-precipitable blood plasma and in the TCA-precipitable fraction of the liver. The other examined organs and tissues showed smaller differences between the test animals. The results show that the /sup 15/N labelling of tissues and organs of pigs is also possible at a high level of protein supply by means of an oral application of (/sup 15/N) ammonia salts.

Determination of the δ15N of nitrate in solids; RSIL lab code 2894

Science.gov (United States)

Coplen, Tyler B.; Qi, Haiping; Revesz, Kinga; Casciotti, Karen; Hannon, Janet E.

2007-01-01

The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 2894 is to determine the δ15N of nitrate (NO3-) in solids. The nitrate fraction of the nitrogen species is dissolved by water (called leaching) and can be analyzed by the bacterial method covered in RSIL lab code 2899. After leaching, the δ15N of the dissolved NO3- is analyzed by conversion of the NO3- to nitrous oxide (N2O), which serves as the analyte for mass spectrometry. A culture of denitrifying bacteria is used in the enzymatic conversion of NO3- to N2O, which follows the pathway shown in equation 1: NO3- → NO2- → NO → 1/2 N2O (1) Because the bacteria Pseudomonas aureofaciens lack N2O reductive activity, the reaction stops at N2O, unlike the typical denitrification reaction that goes to N2. After several hours, the conversion is complete, and the N2O is extracted from the vial, separated from volatile organic vapor and water vapor by an automated -65 °C isopropanol-slush trap, a Nafion drier, a CO2 and water removal unit (Costech #021020 carbon dioxide absorbent with Mg(ClO4)2), and trapped in a small-volume trap immersed in liquid nitrogen with a modified Finnigan MAT (now Thermo Scientific) GasBench 2 introduction system. After the N2O is released, it is further purified by gas chromatography before introduction to the isotope-ratio mass spectrometer (IRMS). The IRMS is a Thermo Scientific Delta V Plus continuous flow IRMS (CF-IRMS). It has a universal triple collector, consisting of two wide cups with a narrow cup in the middle; it is capable of simultaneously measuring mass/charge (m/z) of the N2O molecule 44, 45, and 46. The ion beams from these m/z values are as follows: m/z = 44 = N2O = 14N14N16O; m/z = 45 = N2O = 14N15N16O or 14N14N17O; m/z = 46 = N2O = 14N14N18O. The 17O contributions to the m/z 44 and m/z 45 ion beams are accounted for before δ15N values are reported.

15N in tree rings as a bio-indicator of changing nitrogen cycling in tropical forests: an evaluation at three sites using two sampling methods

NARCIS (Netherlands)

Sleen, van der J.P.; Vlam, M.; Groenendijk, P.; Anten, N.P.R.; Bongers, F.; Bunyavejchewin, S.; Hietz, P.; Pons, T.L.; Zuidema, P.

2015-01-01

Anthropogenic nitrogen deposition is currently causing a more than twofold increase of reactive nitrogen input over large areas in the tropics. Elevated N-15 abundance (delta N-15) in the growth rings of some tropical trees has been hypothesized to reflect an increased leaching of N-15-depleted

Mechanism of the reactions 14N(d,p)15N and 14N(d,n)15O by Doppler shift line shape method

International Nuclear Information System (INIS)

Abdel-Moneim, A.M.

1976-06-01

In this investigation the total and the differential absolute cross sections of the 14 N(d,p) 15 N reaction leading to excited states at 7.3, 8.3 and 9.05 MeV levels in 15 N and the 14 N(d,n) 15 O reaction leading to the 6.79 MeV level in 15 O, have been studied over the energy range from 0.5 MeV to 3 MeV. Doppler shift line shape method as well as γ-ray yield measurements have been used. The absolute cross sections are determined relative to the known 14 N(p,p) elastic differential cross sections. A comparison with previously determined values for the same reactions at selected energies shows good agreement in angular distribution as well as in absolute values. The total cross section for the d,p reaction shows a general energy dependence which is typical for direct reactions, but with minor contribution from compound nucleus formation at certain energy ranges. For the 14 N(d,n) 15 N reaction, the method applied is unique, since it allows the differential cross section to be studied all the way down to the threshold energy of deuterons at 2 MeV, with a detectorsystem efficiency which is constant over the entire range of neutron energies. The larger part of the energy range that has been investigated is dominated by a resonance at 2.55 π+ 0.05 MeV deuteron energy and a halfwidth depending on the amount of contribution from the direct reaction of the order of 200-400 keV. (JIW)

Influence of diet on the distribution of nitrogen isotopes in animals

International Nuclear Information System (INIS)

DeNiro, M.J.; Epstein, S.

1981-01-01

The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The delta 15 N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different delta 15 N values. The variability of the relationship between the delta 15 N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in 15 N relative to the diet, with the difference between the delta 15 N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The delta 15 N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the delta 15 N value of the diet. The dependence of the delta 15 N values of whole animals and their tissues and biochemical components on the delta 15 N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different delta 15 N values. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the delta 13 C and delta 15 N values of bone collagen suggest that C 4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis. (author)

Influence of diet on the distribution of nitrogen isotopes in animals

Energy Technology Data Exchange (ETDEWEB)

DeNiro, M J; Epstein, S [California Inst. of Tech., Pasadena (USA). Div. of Geological Sciences

1981-03-01

The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The delta/sup 15/N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different delta/sup 15/N values. The variability of the relationship between the delta/sup 15/N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in /sup 15/N relative to the diet, with the difference between the delta/sup 15/N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The delta/sup 15/N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the delta/sup 15/N value of the diet. The dependence of the delta/sup 15/N values of whole animals and their tissues and biochemical components on the delta/sup 15/N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different delta/sup 15/N values. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the delta/sup 13/C and delta/sup 15/N values of bone collagen suggest that C/sub 4/ and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Dominant transverse-electric polarized emission from 298 nm MBE-grown AlN-delta-GaN quantum well ultraviolet light-emitting diodes

Science.gov (United States)

Liu, Cheng; Ooi, Yu Kee; Islam, S. M.; Xing, Huili Grace; Jena, Debdeep; Zhang, Jing

2017-02-01

III-nitride based ultraviolet (UV) light emitting diodes (LEDs) are of considerable interest in replacing gas lasers and mercury lamps for numerous applications. Specifically, AlGaN quantum well (QW) based LEDs have been developed extensively but the external quantum efficiencies of which remain less than 10% for wavelengths UV wavelengths is by the use of the AlGaN-delta-GaN QW where the insertion of the delta-GaN layer can ensure the dominant conduction band (C) - heavyhole (HH) transition, leading to large transverse-electric (TE) optical output. Here, we proposed and investigated the physics and polarization-dependent optical characterizations of AlN-delta- GaN QW UV LED at 300 nm. The LED structure is grown by Molecular Beam Epitaxy (MBE) where the delta-GaN layer is 3-4 monolayer (QW-like) sandwiched by 2.5-nm AlN sub-QW layers. The physics analysis shows that the use of AlN-delta-GaN QW ensures a larger separation between the top HH subband and lower-energy bands, and strongly localizes the electron and HH wave functions toward the QW center and hence resulting in 30-time enhancement in TEpolarized spontaneous emission rate, compared to that of a conventional Al0.35Ga0.65N QW. The polarization-dependent electroluminescence measurements confirm our theoretical analysis; a dominant TE-polarized emission was obtained at 298 nm with a minimum transverse-magnetic (TM) polarized emission, indicating the feasibility of high-efficiency TEpolarized UV emitters based on our proposed QW structure.

Holocene evolution of a wave-dominated fan-delta: Godavari delta, India

Science.gov (United States)

Saito, Y.; Nageswara Rao, K.; Nagakumar, K.; Demudu, G.; Rajawat, A.; Kubo, S.; Li, Z.

2013-12-01

sediments also indicates erosional environments during the formation of the linear shoreline. We interpret this unconformity as a wave-ravinement surface in a regressive delta succession reflecting the decrease of sediment supply due to lobe shifts (or avulsion), and not as a marine erosion surface due to forced regression. Similar erosion surface is recognized in the Yellow River delta (Saito et al., 2000). Discrimination of either surface for ancient sediments and rocks in a wave-dominated setting will be important in sequence-stratigraphic interpretation. Coastal erosion and deposition have occurred in wave-dominated deltas naturally on centennial to millenneial time scales, resulting in delta progradation during the Holocene. However recent decrease of sediment discharge due to dam construction and irrigation on decadal time scales has been exacerbating coastal erosion significantly, resulting in delta shrinking in the Godavari delta. Nageswara Rao, K., Sadakata, N.: In Kay, R. (Ed.), Deltas of the World. American Society of Civil Engineers, New York, 1-15, 1993. Nageswara Rao, K. et al.: In Bhattacharya, J.P., Gioson, L. (Eds.), River Deltas--Concepts, Models and Examples: SEPM Special Publication 83, 435-451, 2005. Nageswara Rao, K. et al.: Geomorphology 175-176, 163¬-175, 2012. Saito, Y. et al.: J Asian Earth Sci. 18, 489-497, 2000.

$\\gamma N \\to \\Delta$ transition form factors in Quenched and $N_F=2$ QCD

CERN Document Server

Alexandrou, C; Lippert, T; Neff, H; Negele, J W; Schilling, K; Schroers, W; Tsapalis, A; Forcrand, Ph. de; Lippert, Th.

2003-01-01

Calculations of the magnetic dipole, electric quadrupole and Coulomb quadrupole amplitudes for the transition $\\gamma N\\to \\Delta$ are presented both in quenched QCD and with two flavours of degenerate dynamical quarks.

Use of low enriched /sup 15/N/sub 2/ for symbiotic fixation tests

Energy Technology Data Exchange (ETDEWEB)

Victoria, R L

1975-01-01

Gaseous atmospheres containing /sup 15/N/sub 2/ with low enrichment were used to test symbiotic nitrogen fixation in beans (Phaseolus vulgari, L.). The tests of fixation in nodulated roots and the tests of fixation in the whole plant, in which the plants were placed inside a specially constructed growth chamber, gave positive results and suggest that the methodology used can be very helpfull in more detailed studies on symbiotic fixation. Samples of atmospheric air were purified by absorption of O/sub 2/ and CO/sub 2/ by two methods. The purified N/sub 2/ obtained was analysed and the results were compared. Samples of bean plant material were collected in natural conditions and analysed for /sup 15/N natural variation. Several samples were prepared for /sup 15/N isotopic analysis by two methods. The results obtained were compared. All samples were analysed in an Atlas-Varian Ch-4 model mass spectrometer, and the results were given in delta /sup 15/N/sub 0///sup 00/ variation in relation to a standard gas.

Changes in mineral 15 N from soils treated with 15 N-urea and 15 N-vinasse incorporated or not to sugar cane straw

International Nuclear Information System (INIS)

Silva, Vilma M.; Colaco, Waldeciro; Encarnacao, Fernando A.F.

1999-01-01

Changes in N derived from 15 N sources (urea and vinasse), applied to two soils differing in texture (PV sandy, LR clayey), incorporated or not to sugar cane straw (dry leaves and sheathes) and incubated in an open system for 35 days, were evaluated through an isotope technique. Soil samples were collected 7, 14, 21, 28 and 35 days after applications to determine nitrogen fractions (total-N, N H 4 + - N and NO 3 - - N) derived from the labelled sources. Mineral N was taken as the sum of N H 4 + - N and N H 3 - -N. 15 N-abundances were determined in the concentrated extracts of these fractions. The mineral N net transformation rates were found from the mineral N obtained by taking the difference between the values of two subsequent incubation times. The results showed that mineral N transformation rates were initially positives in the treatments of 15 N-urea, and significantly higher (10,30 mg kg -1 d -1 , PV and 8,08 mg kg -1 d -1 , LR) than those obtained in the treatments with 15 N vinasse (1,11 mg kg -1 dia -1 , PV and 0,55 mg kg -1 dia -1 , LR). In general terms, mineral-N net transformation rates were negative (0,06 and 0,26 mg.kg -1 d -1 , PV; -1,44 and 0,07 mg.kg -1 .d -1 , LR, respective;y for urea and vinasse) indicating prevalence of immobilization. The results also showed small fluctuations among treatments at some of the incubation periods, which reflects the influence of characteristics and properties of both soils. (author)

Human dietary δ(15)N intake: representative data for principle food items.

Science.gov (United States)

Huelsemann, F; Koehler, K; Braun, H; Schaenzer, W; Flenker, U

2013-09-01

Dietary analysis using δ(15)N values of human remains such as bone and hair is usually based on general principles and limited data sets. Even for modern humans, the direct ascertainment of dietary δ(15)N is difficult and laborious, due to the complexity of metabolism and nitrogen fractionation, differing dietary habits and variation of δ(15)N values of food items. The objective of this study was to summarize contemporary regional experimental and global literature data to ascertain mean representative δ(15)N values for distinct food categories. A comprehensive data set of more than 12,000 analyzed food samples was summarized from the literature. Data originated from studies dealing with (1) authenticity tracing or origin control of food items, and (2) effects of fertilization or nutrition on δ(15)N values of plants or animals. Regional German food δ(15)N values revealed no major differences compared with the mean global values derived from the literature. We found that, in contrast to other food categories, historical faunal remains of pig and poultry are significantly enriched in (15)N compared to modern samples. This difference may be due to modern industrialized breeding practices. In some food categories variations in agricultural and feeding regimens cause significant differences in δ(15)N values that may lead to misinterpretations when only limited information is available. Copyright © 2013 Wiley Periodicals, Inc.

Measurement of the delta34S value in methionine by double spike multi-collector thermal ionization mass spectrometry using Carius tube digestion.

Science.gov (United States)

Mann, Jacqueline L; Kelly, W Robert

2010-09-15

Methionine is an essential amino acid and is the primary source of sulfur for humans. Using the double spike ((33)S-(36)S) multi-collector thermal ionization mass spectrometry (MC-TIMS) technique, three sample bottles of a methionine material obtained from the Institute for Reference Materials and Measurements have been measured for delta(34)S and sulfur concentration. The mean delta(34)S value, relative to Vienna Canyon Diablo Troilite (VCDT), determined was 10.34 +/- 0.11 per thousand (n = 9) with the uncertainty reported as expanded uncertainties (U). These delta(34)S measurements include a correction for blank which has been previously ignored in studies of sulfur isotopic composition. The sulfur concentrations for the three bottles range from 56 to 88 microg/g. The isotope composition and concentration results demonstrate the high accuracy and precision of the DS-MC-TIMS technique for measuring sulfur in methionine.

Late Pleistocene Vegetation, Climate and Relative Sea Level Changes in the Southeastern Brazilian Coast, Based on C and N Isotopes and Bio Indicator Analysis of Mangrove Organic Matter

Energy Technology Data Exchange (ETDEWEB)

Pessenda, L. C.R.; Vidotto, E.; Buso, Jr., A. A.; Assarini, Jr., J. P.; Bendassollia, J. A. [Center for Nuclear Energy in Agriculture (CENA), University of Sao Paulo (USP), Piracicaba, Sao Paulo (Brazil); De Oliveira, P. E. [University of Guarulhos (UNG), Guarulhos, Sao Paulo (Brazil); Macias, F. [' ' Luiz de Queiroz' ' College of Agriculture/USP, Piracicaba, Sao Paulo (Brazil); Ricardi-Branco, F. [University of Campinas - Geosciences Institute, Campinas, Sao Paulo (Brazil)

2013-07-15

On the southeastern Brazilian coast, mangrove organic matter records have been studied by C and N isotopes, pollen and diatom analysis to reconstruct 40 ka of vegetation and climatic history. The {delta}{sup 13}C and {delta}{sup 15}N presented more depleted values from 40 to 19 ka BP. The high C/N ratios and depleted isotopic values indicate the predominance of C3 land plants in the location presently occupied by the mangrove vegetation, and a lower sea level than today. The presence of pollen of Ilex, Weinmannia, Symplocos, Drimys and Podocarpus suggest a colder and more humid climate than present. From 19 to 2.2 ka BP a sedimentary hiatus is associated with a sea level rise. The presence of mangrove in its present position since at least 2.200 a BP and the return of the marine coastline are associated with the lowest C/N ratio, more enriched {delta}{sup 13}C and {delta}{sup 15}N values and the presence of marine diatoms. (author)

Two new organic reference materials for δ13C and δ15N measurements and a new value for the δ13C of NBS 22 oil

Science.gov (United States)

Qi, Haiping; Coplen, Tyler B.; Geilmann, Heike; Brand, Willi A.; Böhlke, J.K.

2003-01-01

Analytical grade L-glutamic acid is chemically stable and has a C/N mole ratio of 5, which is close to that of many of natural biological materials, such as blood and animal tissue. Two L-glutamic acid reference materials with substantially different 13C and 15N abundances have been prepared for use as organic reference materials for C and N isotopic measurements. USGS40 is analytical grade L-glutamic acid and has a δ13C value of −26.24‰ relative to VPDB and a δ15N value of −4.52‰ relative to N2 in air. USGS41 was prepared by dissolving analytical grade L-glutamic acid with L-glutamic acid enriched in 13C and 15N. USGS41 has a δ13C value of +37.76‰ and a δ15N value of +47.57‰. The δ13C and δ15N values of both materials were measured against the international reference materials NBS 19 calcium carbonate (δ13C = +1.95‰), L-SVEC lithium carbonate (δ13C = −46.48‰), IAEA-N-1 ammonium sulfate (δ15N = 0.43‰), and USGS32 potassium nitrate (δ15N = 180‰) by on-line combustion continuous-flow and off-line dual-inlet isotope-ratio mass spectrometry. Both USGS40 and USGS41 are isotopically homogeneous; reproducibility of δ13C is better than 0.13‰, and that of δ15N is better than 0.13‰ in 100-μg amounts. These two isotopic reference materials can be used for (i) calibrating local laboratory reference materials, and (ii) quantifying drift with time, mass-dependent fractionations, and isotope-ratio-scale contraction in the isotopic analysis of various biological materials. Isotopic results presented in this paper yield a δ13C value for NBS 22 oil of −29.91‰, in contrast to the commonly accepted value of −29.78‰ for which off-line blank corrections probably have not been quantified satisfactorily.

15N tracer techniques in pediatric research

International Nuclear Information System (INIS)

Heine, W.; Richter, I.; Plath, C.; Wutzke, K.; Stolpe, H.J.; Tiess, M.; Toewe, J.

1983-01-01

The main topics of the review comprise mathematical fundamentals of the determination of N metabolism parameters using the 3-pool method, the value of different 15 N tracer substances for the determination of whole-body protein parameters, the utilization of parenterally applied D-amino acids, studies on the influence of different diets on the N metabolism of premature infants with the 15 N tracer technique, the application of the 15 N-glycine-STH-test for the evaluation of the therapeutic effect of STH in children suffering from hypothalamico-hypophyseal dwarfism, in vivo studies on urea utilization by the infant intestinal flora under various dietary regimens as well as in vitro investigations on the utilization of 15 N-labelled urea and NH 4 Cl, resp., by the intestinal flora

Observations of the D, E and delta mesons in π-p interactions at 12 and 15 GeV/c

International Nuclear Information System (INIS)

Corden, M.J.; Dowell, J.D.; Garvey, J.

1978-07-01

The D(1285), E(1420) and delta(975) mesons produced in 12 and 15 GeV/c π - p interactions at the CERN Omega Spectrometer have been observed. Production cross sections and decay branching ratios are presented. Analysis of the decay D(1285) → delta(975) π favours a spin parity assignment of 1 + . (author)

15N NMR study on cyanide (C15N-) complex of cytochrome P-450cam. Effects of d-camphor and putidaredoxin on the iron-ligand structure

International Nuclear Information System (INIS)

Shiro, Yoshitsugu; Iizuka, Tetsutaro; Makino, Ryu; Ishimura, Yuzuru; Morishima, Isao

1989-01-01

The cyanide (C 15 N - ) complex of Pseudomonas putida cytochrome P-450 (P-450 cam ) exhibited well-resolved and hyperfine-shifted 15 N NMR resonances arising from the iron-bound C 15 N - at 423 and 500 ppm in the absence and presence of the substrate, d-camphor, respectively. The values were smaller than those for cyanide complexes of myoglobin and hemoglobin (∼ 1000 ppm) but fell into the same range as those for the cyanide complexes of peroxidases (∼ 500 ppm). The 15 N shift values of P-450 cam were not incompatible with the existence of anionic ligand, such as cysteinyl thiolate anion, at the fifth coordination site of heme iron. The difference in the 15 N chemical shift values between camphor-free and bound enzymes was inferred by the increase in the steric constraint to the Fe-C-N bond upon substrate binding

Cyclopentenone prostaglandins as potential inducers of phase II detoxification enzymes. 15-deoxy-delta(12,14)-prostaglandin j2-induced expression of glutathione S-transferases.

Science.gov (United States)

Kawamoto, Y; Nakamura, Y; Naito, Y; Torii, Y; Kumagai, T; Osawa, T; Ohigashi, H; Satoh, K; Imagawa, M; Uchida, K

2000-04-14

Exposure of cells to a wide variety of chemoprotective compounds confers resistance to a broad set of carcinogens. For a subset of the chemoprotective compounds, protection is generated by an increase in the abundance of protective enzymes, such as glutathione S-transferases (GSTs). In the present study, we developed a cell culture system that potently responds to phenolic antioxidants and found that antitumor prostaglandins (PGs) are potential inducers of GSTs. We screened primary hepatocytes and multiple cell lines for inducing GST activity upon incubation with the phenolic antioxidant (tert-butylhydroquinone) and found that rat liver epithelial RL34 cells most potently responded. Based on an extensive screening of diverse chemical agents on the induction of GST activity in RL34 cells, the J2 series of PGs, 15-deoxy-Delta(12,14)-prostaglandin J2 (15-deoxy-Delta(12,14)-PGJ2) in particular, were found to be potential inducers of GST. Enhanced gene expression of Class pi GST isozyme (GSTP1) by 15-deoxy-Delta(12,14)-PGJ2 was evident as a drastic elevation of the mRNA level. Hence, we examined the molecular mechanism underlying the 15-deoxy-Delta(12, 14)-PGJ2-induced GSTP1 gene expression. From functional analysis of various deletion mutant genes, we found that the 15-deoxy-Delta(12, 14)-PGJ2 reponse element was localized in a region containing a GSTP1 enhancer I (GPEI) that consists of two imperfect phorbol 12-O-tetradecanoylphorbol-13-acetate response elements. When the GPEI was combined with the minimum GSTP1 promoter, the element indeed showed an enhancer activity in response to 15-deoxy-Delta(12, 14)-PGJ2. Point mutations of either of the two imperfect 12-O-tetradecanoylphorbol-13-acetate response elements in GPEI completely abolished the enhancer activity. Gel mobility shift assays demonstrated that 15-deoxy-Delta(12,14)-PGJ2 specifically stimulated the binding of nuclear proteins including the transcription factor c-Jun, but not Nrf2, to GPEI. These results

A point-value enhanced finite volume method based on approximate delta functions

Science.gov (United States)

Xuan, Li-Jun; Majdalani, Joseph

2018-02-01

We revisit the concept of an approximate delta function (ADF), introduced by Huynh (2011) [1], in the form of a finite-order polynomial that holds identical integral properties to the Dirac delta function when used in conjunction with a finite-order polynomial integrand over a finite domain. We show that the use of generic ADF polynomials can be effective at recovering and generalizing several high-order methods, including Taylor-based and nodal-based Discontinuous Galerkin methods, as well as the Correction Procedure via Reconstruction. Based on the ADF concept, we then proceed to formulate a Point-value enhanced Finite Volume (PFV) method, which stores and updates the cell-averaged values inside each element as well as the unknown quantities and, if needed, their derivatives on nodal points. The sharing of nodal information with surrounding elements saves the number of degrees of freedom compared to other compact methods at the same order. To ensure conservation, cell-averaged values are updated using an identical approach to that adopted in the finite volume method. Here, the updating of nodal values and their derivatives is achieved through an ADF concept that leverages all of the elements within the domain of integration that share the same nodal point. The resulting scheme is shown to be very stable at successively increasing orders. Both accuracy and stability of the PFV method are verified using a Fourier analysis and through applications to the linear wave and nonlinear Burgers' equations in one-dimensional space.

Observation of the D, E and delta mesons in π-p interactions at 12 and 15 GeV/c

International Nuclear Information System (INIS)

Corden, M.J.; Dowell, J.D.; Garvey, J.; Jobes, M.; Kenyon, I.R.; Mawson, J.; McMahon, T.J.; Corbett, I.F.; Esterling, R.J.; Lipman, N.H.; Litchfield, P.J.; Sumorok, K.C.T.O.; Bellamy, E.H.; Green, M.G.; Harnew, N.; Lister, J.B.; Lister, J.R.; Robertson, A.W.; Stacey, B.J.; Strong, J.A.; Thomas, D.H.

1978-01-01

The authors have observed the D(1285), E(1420) and delta(975) mesons produced in 12 and 15 GeV/c π - p interactions at the CERN Omega Spectrometer. Production cross sections and decay branching ratios are presented. Analysis of the decay D(1285)→delta(975)π favours a spin-parity assignment of 1 + . (Auth.)

Unambiguous amplitude analysis of NN {yields} {Delta}N transition from asymmetry measurements

Energy Technology Data Exchange (ETDEWEB)

Auger, J.P. [Universite d`Orleans (France). Lab. de Physique Theorique; Lazard, C. [Paris-11 Univ., 91 - Orsay (France). Div. de Physique Theorique

1997-12-31

For particular {Delta}-production angles, an unambiguous determination of the NN {yields} {Delta}N transition amplitudes is performed, from NN {yields} (N{pi})N experiments, in which the polarization states are measured in the entrance channel, only. A three-step method is developed, which determines, firstly, the magnitudes of the amplitudes, secondly, independent relative phases, and thirdly, some dependent relative phases for resolving the remaining discrete ambiguities. A rule of ambiguity elimination is applied, which is based on the closure of a chain of consecutive independent relative phases, by means of the ad-hoc dependent one. A generalization of this rule is given, for the case of a non-diagonal matrix connecting observables and bilinear combinations of amplitudes. (author) 18 refs.

Variations in natural abundances of 15N and 13C in potassium fed lentil plants grown under water stress

International Nuclear Information System (INIS)

Kurdali, F.; Al-Shammaa, M.

2009-01-01

The impact of two K-fertilizer treatments [K0 (0) and K1 (150 kg K 2 O/ha)] on dry matter production and N 2 fixation (Ndfa) by Lentil (Lens culinaris.) was evaluated in a pot experiment. The plants were also subjected to three soil moisture regimes starting from bud flower initiation stage to pod formation (low, 45-50%. Moderate, 55-60% and high 75-80% of field capacity, abbreviated as FC1, FC2 and FC3, respectively). The 15 N natural abundance technique (%δ 15 N) was employed to evaluate N 2 fixation using barley as a reference crop. Moreover, the carbon isotope discrimination (%Δ 13 C) was determined to assess factors responsible for crop performance variability in the different treatments. Water restriction occurring during the post-flowering period considerably affects growth and N 2 -fixation. However, K-fertilizer enhanced plant performance by overcoming water shortage influences. The delta 15 N values in lentils ranged from +0.67 to +1.36% depending on soil moisture and K-fertilizer treatments. Whereas, those of N 2 fixation and the reference plant were -0.45 and +2.94%, respectively. Consequently, Ndfa% ranged from 45 and 65%. Water stress reduced Δ 13 C values in the FC1K0 And FC1K1 treatments. However, K fertilizer enhanced the whole plants Δ 13 C along with dry matter yield and N 2 fixation. The water stressed plants amended with K (FC1K1) seemed to be the best treatment because of its highest pod yield, high N balance and N 2 -fixation with low consumption of irrigation water. This illustrates the ecological and economical importance of K-fertilizer in alleviating water stress occurring during the post-flowering period of lentil.(Authors)

Determination of the δ15N and δ18O of nitrate in water; RSIL lab code 2900

Science.gov (United States)

Coplen, Tyler B.; Qi, Haiping; Revesz, Kinga; Casciotti, Karen; Hannon, Janet E.

2007-01-01

The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 2900 is to determine the δ15N and δ18O of nitrate (NO3-) in water. The δ15N and δ18O of the dissolved NO3- are analyzed by converting the NO3- to nitrous oxide (N2O), which serves as the analyte for mass spectrometry. A culture of denitrifying bacteria is used in the enzymatic conversion of the NO3- to N2O, which follows the pathway shown in equation 1: NO3- → NO2- → NO → 1/2 N2O (1) Because the bacteria Pseudomonas aureofaciens lack N2O reductive activity, the reaction stops at N2O, unlike the typical denitrification reaction that goes to N2. After several hours, the conversion is complete, and the N2O is extracted from the vial, separated from volatile organic vapor and water vapor by an automated -65 °C isopropanol-slush trap, a Nafion drier, a CO2 and water removal unit (Costech #021020 carbon dioxide absorbent with Mg(ClO4)2), and trapped in a small-volume trap immersed in liquid nitrogen with a modified Finnigan MAT (now Thermo Scientific) GasBench 2 introduction system. After the N2O is released, it is further purified by gas chromatography before introduction to the isotope-ratio mass spectrometer (IRMS). The IRMS is a Thermo Scientific Delta V Plus continuous flow IRMS (CF-IRMS). It has a universal triple collector, consisting of two wide cups with a narrow cup in the middle; it is capable of simultaneously measuring mass/charge (m/z) of the N2O molecule 44, 45, and 46. The ion beams from these m/z values are as follows: m/z = 44 = N2O = 14N14N16O; m/z = 45 = N2O = 14N15N16O or 14N14N17O; m/z = 46 = N2O = 14N14N18O. The 17O contributions to the m/z 44 and m/z 45 ion beams are accounted for before δ15N values are reported.

[Characteristics of foliar delta13C values of common shrub species in various microhabitats with different karst rocky desertification degrees].

Science.gov (United States)

Du, Xue-Lian; Wang, Shi-Jie; Rong, Li

2011-12-01

By measuring the foliar delta13C values of 5 common shrub species (Rhamnus davurica, Pyracantha fortuneana, Rubus biflorus, Zanthoxylum planispinum, and Viburnum utile) growing in various microhabitats in Wangjiazhai catchment, a typical karst desertification area in Guizhou Province, this paper studied the spatial heterogeneity of plant water use at niche scale and the response of the heterogeneity to different karst rocky desertification degrees. The foliar delta13C values of the shrub species in the microhabitats followed the order of stony surface > stony gully > stony crevice > soil surface, and those of the majority of the species were more negative in the microhabitat soil surface than in the others. The foliar delta13C values decreased in the sequence of V. utile > R. biflorus > Z. planispinum > P. fortuneana > R. davurica, and the mean foliar delta13C value of the shrubs and that of typical species in various microhabitats all increased with increasing karst rocky desertification degree, differed significantly among different microhabitats. It was suggested that with the increasing degree of karst rocky desertification, the structure and functions of karst habitats were impaired, microhabitats differentiated gradually, and drought degree increased.

Investigation into endogenous N metabolism in 15N-labelled pigs. 1

International Nuclear Information System (INIS)

Bergner, H.; Bergner, U.; Adam, K.

1984-01-01

4 male castrated pigs (55-65 kg) either received a wheat-fish meal diet (1 and 2) or a wheat-horse bean diet (3 and 4) without straw meal supplement (1 and 3) or with a supplement of 20% dry matter (2 and 4). In order to investigate whether a 15 N labelling of the pigs is also possible with a protein excess in the ration, the animals received 24.8 g (1 and 2) and 11.6 g crude protein/kg/sup 0.75/ live weight (3 and 4). During a 10-day 15 N-labelling 385 mg 15 N excess ( 15 N') per kg/sup 0.75/ were applied with 15 N labelling the following quotas of the applied 15 N amount were incorporated: 1 = 10.2%, 2 = 7.2%, 3 = 18.7%, 4 = 14.4%. 15 N excretion in both TCA fractions of feces showed a highly significant positive correlation to the increasing content of crude fibre in the 4 diets. The immediate 15 N incorporation into the TCA-precipitable fraction of feces proves that 15 N enters the large intestine endogenously and serves bacterial protein synthesis. 3 days after the last 15 application the pigs were killed. The values of atom-% 15 N' were determined in the TCA-precipitable blood plasma and in the TCA-precipitable fraction of the liver. The other examined organs and tissues showed smaller differences between the test animals. The results show that the 15 N labelling of tissues and organs of pigs is also possible at a high level of protein supply by means of an oral application of [ 15 N] ammonia salts. (author)

Concentrations and (delta)13C values of atmospheric CO2 from oceanic atmosphere through time: polluted and non-polluted areas

International Nuclear Information System (INIS)

Longinelli, Antonio; Selmo, Enrico; Lenaz, Renzo; Ori, Carlo

2005-01-01

rate of about 1.7 ppmv/yr in excellent agreement with the NOAA/WMO data from land-based stations). Simultaneously, the mean (delta) 13 C value of atmospheric CO 2 over the Central Indian Ocean (Equator) decreased from -0.792% at the end of 1998 to -0.822% at the end of 2003; the mean decrease rate being of about -0.006%/yr. This rate as well as that calculated at 12 deg S (-0.005%/yr) are not far from the rates that may be calculated according to the data from the nearest NOAA sites (Crozet and Mahe islands); the rates calculated South of Australia and between Tasmania and N.Z. are almost identical to those calculated according to the data from Cape Grim NOAA site (Tasmania)

Observation of the D, E and delta mesons in pi /sup -/p interactions at 12 and 15 GeV/c

CERN Document Server

Corden, M J; Bellamy, E H; Corbett, I F; Dagan, S; Dowell, John D; Esterling, R J; Garvey, J; Gnat, Y; Green, M G; Harnew, N; Jobes, M; Kenyon, I R; Lipman, Norman H; Lister, J B; Lister, J R; Litchfield, P J; Mawson, J; McMahon, T J; Robertson, A W; Stacey, B J; Strong, J A; Sumorok, K; Thomas, D H

1978-01-01

The authors have observed the D(1285), E(1420) and delta (975) mesons produced in 12 and 15 GeV/c pi /sup -/p interactions at the CERN Omega Spectrometer. Production cross sections and decay branching ratios are presented. Analysis of the decay D(1285) to delta (975) pi favours a spin parity assignment of 1/sup +/. (24 refs).

Carbon and nitrogen isotope variations in tree-rings as records of perturbations in regional carbon and nitrogen cycles.

Science.gov (United States)

Bukata, Andrew R; Kyser, T Kurtis

2007-02-15

Increasing anthropogenic pollution from urban centers and fossil fuel combustion can impact the carbon and nitrogen cycles in forests. To assess the impact of twentieth century anthropogenic pollution on forested system carbon and nitrogen cycles, variations in the carbon and nitrogen isotopic compositions of tree-rings were measured. Individual annual growth rings in trees from six sites across Ontario and one in New Brunswick, Canada were used to develop site chronologies of tree-ring delta 15N and delta 13C values. Tree-ring 615N values were approximately 0.5% per hundred higher and correlated with contemporaneous foliar samples from the same tree, but not with delta 15N values of soil samples. Temporal trends in carbon and nitrogen isotopic compositions of these tree-rings are consistent with increasing anthropogenic influence on both the carbon and nitrogen cycles since 1945. Tree-ring delta 13C values and delta 15N values are correlated at both remote and urban-proximal sites, with delta 15N values decreasing since 1945 and converging on 1% per hundred at urban-proximal sites and decreasing but not converging on a single delta 15N value in remote sites. These results indicate that temporal trends in tree-ring nitrogen and carbon isotopic compositions record the regional extent of pollution.

Disturbance and topography shape nitrogen availability and δ15 N over long-term forest succession

Science.gov (United States)

Perakis, Steven; Tepley, Alan J.; Compton, Jana

2015-01-01

Forest disturbance and long-term succession towards old-growth are thought to increase nitrogen (N) availability and N loss, which should increase soil δ15N values. We examined soil and foliar patterns in N and δ15N, and soil N mineralization, across 800 years of forest succession in a topographically complex montane landscape influenced by human logging and wildfire. In contrast to expectations, we found that disturbance caused declines in surface mineral soil δ15N values, both in logged forests measured 40–50 years after disturbance, and in unlogged forests disturbed by severe wildfire within the last 200 years. Both symbiotic N fixation and N transfers from disturbed vegetation and detritus could lower soil δ15N values after disturbance. A more important role for symbiotic N fixation is suggested by lower soil δ15N values in slow-successional sites with slow canopy closure, which favors early-successional N fixers. Soil δ15N values increased only marginally throughout 800 years of succession, reflecting soil N uptake by vegetation and strong overall N retention. Although post-disturbance N inputs lowered surface soil δ15N values, steady-state mass balance calculations suggest that wildfire combustion of vegetation and detritus can dominate long-term N loss and increase whole-ecosystem δ15N. On steeper topography, declining soil δ15N values highlight erosion and accelerated soil turnover as an additional abiotic control on N balances. We conclude for N-limited montane forests that soil δ15N and N availability are less influenced by nitrate leaching and denitrification loss than by interactions between disturbance, N fixation, and erosion.

[Microbial community in nitrogen cycle of aquaculture water of the Pearl River Delta].

Science.gov (United States)

Cai, Xiaolong; Luo, Jianfei; Lin, Weitie; Tian, Guoliang

2012-05-04

In order to study the characteristic of nitrogen transport, the community structure and diversity of related microorganisms in aquaculture water of the Pearl River Delta. We established an artificial aquaculture ecosystem to study the microbial community of 15N-stable isotope probing (15N-SIP) labeled nitrogen transport microorganisms. The 15N-labeled DNA was separated by CsCl-ethidium bromide density gradient centrifugation, and was used to construct 16S rRNA gene clone libraries of bacteria and archaea. Phylogenetic analysis shows that 19 Operational Taxonomic Units (OTUs) from bacterial library were clustered in Proteobacteria and Planctomycetes. Proteobacteria (99.2%) was the dominant group, mainly consisted of Comamonas (15.7%), Nitrosomonas (12.4%), Enterobacteriaceae (11.5%) and Nitrobacter (11.5%). From archaeal library 9 OTUs were divided into 3 phyla: Thaumarchaeota, Crenarchaeota and Euryarchaeota. We successfully elucidated the microbial community of nitrogen transport microorganisms in aquaculture water of Pearl River Delta by using 15N-SIP. The data of the community will provide essential information for isolating nitrogen degrading microorganism, and provide scientific basis for creating a healthy aquaculture environment.

Nitrogen and carbon isotopes in soil with special reference to the diagnosis of organic matter

International Nuclear Information System (INIS)

Wada, Eitaro; Nakamura, Koichi.

1980-01-01

Distributions of nitrogen and carbon isotopes in terrestrial ecosystems are described based on available data and our recent findings for soil organic matters. Major processes regulating N-isotope and C-isotope ratios in biogenic substances are discussed. The biological di-nitrogen fixation and the precipitation are major sources which lower the delta 15 N value for forested soil organic matters. Denitrification enhances delta 15 N value for soil in cultivated fields. An addition of chemical fertilizer lowers 15 N content in soils. The permiation of soil water is an important factor controlling vertical profiles of delta 15 N in soil systems. Among soil organic matters, non-hydrolizable fraction seems to give unique low delta 15 N value, suggesting the utility of delta 15 N analysis in studying the nature of the fractions. delta 13 C of soil organic matter is significantly lower than that for marine sediments. delta 13 C for soil humus varies with respect to chemical forms as well as an age of soil organic matters. The variation is large in paddy fields. It is, thus, probable that delta 13 C is an useful parameter in studying the early epidiagenesis of soil organic matters. Based on the known delta 15 N-delta 13 C relationships, a two-source mixing model has been applied to assess sources of organic matters in coastal sediment. (author)

Cerebral correlates of delta waves during non-REM sleep revisited.

Science.gov (United States)

Dang-Vu, Thien Thanh; Desseilles, Martin; Laureys, Steven; Degueldre, Christian; Perrin, Fabien; Phillips, Christophe; Maquet, Pierre; Peigneux, Philippe

2005-10-15

We aimed at characterizing the neural correlates of delta activity during Non Rapid Eye Movement (NREM) sleep in non-sleep-deprived normal young adults, based on the statistical analysis of a positron emission tomography (PET) sleep data set. One hundred fifteen PET scans were obtained using H(2)(15)O under continuous polygraphic monitoring during stages 2-4 of NREM sleep. Correlations between regional cerebral blood flow (rCBF) and delta power (1.5-4 Hz) spectral density were analyzed using statistical parametric mapping (SPM2). Delta power values obtained at central scalp locations negatively correlated during NREM sleep with rCBF in the ventromedial prefrontal cortex, the basal forebrain, the striatum, the anterior insula, and the precuneus. These regions embrace the set of brain areas in which rCBF decreases during slow wave sleep (SWS) as compared to Rapid Eye Movement (REM) sleep and wakefulness (Maquet, P., Degueldre, C., Delfiore, G., Aerts, J., Peters, J.M., Luxen, A., Franck, G., 1997. Functional neuroanatomy of human slow wave sleep. J. Neurosci. 17, 2807-S2812), supporting the notion that delta activity is a valuable prominent feature of NREM sleep. A strong association was observed between rCBF in the ventromedial prefrontal regions and delta power, in agreement with electrophysiological studies. In contrast to the results of a previous PET study investigating the brain correlates of delta activity (Hofle, N., Paus, T., Reutens, D., Fiset, P., Gotman, J., Evans, A.C., Jones, B.E., 1997. Regional cerebral blood flow changes as a function of delta and spindle activity during slow wave sleep in humans. J. Neurosci. 17, 4800-4808), in which waking scans were mixed with NREM sleep scans, no correlation was found with thalamus activity. This latter result stresses the importance of an extra-thalamic delta rhythm among the synchronous NREM sleep oscillations. Consequently, this rCBF distribution might preferentially reflect a particular modulation of the

DELTAS: A new Global Delta Sustainability Initiative (Invited)

Science.gov (United States)

Foufoula-Georgiou, E.

2013-12-01

Deltas are economic and environmental hotspots, food baskets for many nations, home to a large part of the world population, and hosts of exceptional biodiversity and rich ecosystems. Deltas, being at the land-water interface, are international, regional, and local transport hubs, thus providing the basis for intense economic activities. Yet, deltas are deteriorating at an alarming rate as 'victims' of human actions (e.g. water and sediment reduction due to upstream basin development), climatic impacts (e.g. sea level rise and flooding from rivers and intense tropical storms), and local exploration (e.g. sand or aggregates, groundwater and hydrocarbon extraction). Although many efforts exist on individual deltas around the world, a comprehensive global delta sustainability initiative that promotes awareness, science integration, data and knowledge sharing, and development of decision support tools for an effective dialogue between scientists, managers and policy makers is lacking. Recently, the international scientific community proposed to establish the International Year of Deltas (IYD) to serve as the beginning of such a Global Delta Sustainability Initiative. The IYD was proposed as a year to: (1) increase awareness and attention to the value and vulnerability of deltas worldwide; (2) promote and enhance international and regional cooperation at the scientific, policy, and stakeholder level; and (3) serve as a launching pad for a 10-year committed effort to understand deltas as complex socio-ecological systems and ensure preparedness in protecting and restoring them in a rapidly changing environment. In this talk, the vision for such an international coordinated effort on delta sustainability will be presented as developed by a large number of international experts and recently funded through the Belmont Forum International Opportunities Fund. Participating countries include: U.S., France, Germany, U.K., India, Japan, Netherlands, Norway, Brazil, Bangladesh

Stable carbon ({sup 12/13}C) and nitrogen ({sup 14/15}N) isotopes as a tool for identifying the sources of cyanide in wastes and contaminated soils-A method development

Energy Technology Data Exchange (ETDEWEB)

Weihmann, Jenny [Arbeitsgruppe Bodengeographie/Bodenkunde, Geographisches Institut, Universitaet zu Koeln, D-50923 Cologne (Germany); Mansfeldt, Tim [Arbeitsgruppe Bodengeographie/Bodenkunde, Geographisches Institut, Universitaet zu Koeln, D-50923 Cologne (Germany)]. E-mail: tim.mansfeldt@uni-koeln.de; Schulte, Ulrike [Lehrstuhl fuer Sediment- und Isotopengeologie, Institut fuer Geologie, Mineralogie und Geophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2007-01-23

The occurrence of iron-cyanide complexes in the environment is of concern, since they are potentially hazardous. In order to determine the source of iron-cyanide complexes in contaminated soils and wastes, we developed a method based on the stable isotope ratios {sup 13}C/{sup 12}C and {sup 15}N/{sup 14}N of the complexed cyanide-ion (CN{sup -}). The method was tested on three pure chemicals and two industrials wastes: blast-furnace sludge (BFS) and gas-purifier waste (GPW). The iron-cyanide complexes were converted into the solid cupric ferrocyanide, Cu{sub 2}[Fe(China){sub 6}].7H{sub 2}O, followed by combustion and determination of the isotope-ratios by continuous flow isotope ratio mass spectrometry. Cupric ferrocyanide was obtained from the materials by (i) an alkaline extraction with 1 M NaOH and (ii) a distillate digestion. The [Fe(China){sub 6}]{sup 4-} of the alkaline extraction was precipitated after adding Cu{sup 2+}. The CN{sup -} of the distillate digestion was at first complexed with Fe{sup 2+} under inert conditions and then precipitated after adding Cu{sup 2+}. The {delta} {sup 13}C-values obtained by the two methods differed slightly up to 1-3 per mille for standards and BFS. The difference was larger for alkaline-extracted GPW (4-7 per mille ), since non-cyanide C was co-extracted and co-precipitated. Therefore the distillate digestion technique is recommended when determining the C isotope ratios in samples rich in organic carbon. Since the {delta} {sup 13}C-values of BFS are in the range of -30 to -24 per mille and of -17 to -5 per mille for GPW, carbon seems to be a suitable tracer for identifying the source of cyanide in both wastes. However, the {delta} {sup 15}N-values overlapped for BFS and GPW, making nitrogen unsuitable as a tracer.

Does δ 15N in river food webs reflect the intensity and origin of N loads from the watershed?

International Nuclear Information System (INIS)

Anderson, Caroline; Cabana, Gilbert

2006-01-01

Stable nitrogen isotope ratios (δ 15 N) were measured in invertebrates and fish collected from 82 river sites located in the Saint-Lawrence Lowlands in Quebec, Canada, to examine the relationship between aquatic biota δ 15 N and anthropogenic nitrogen (N) loads. Mean δ 15 N values of all three trophic levels examined (primary consumers, predatory invertebrates and invertebrate-feeding fish) were highly correlated with total anthropogenic N loads on the watershed (kg N km -2 year -1 ; r 2 > 0.61, p 2 > 0.62, p 2 > 0.45, p 2 > 0.29, p 15 N and N loads originating from each of the three livestock species examined (bovines, pigs and poultry; p 15 N (multiple r 2 = 0.67, p 15 N values increasing slowly over a wide range of low levels of N loads, but increasing much faster as N loads grew larger. The three anthropogenic N sources examined were highly correlated with one another, preventing us from statistically isolating their respective effects on δ 15 N. When these loads were expressed as a proportion of total N load, δ 15 N of aquatic biota was still highly correlated with N from livestock and fertilizers, but not with N from human population. Overall, these results suggest that δ 15 N values of aquatic consumers could be used as indicators of the intensity of anthropogenic N loading on watersheds, but not as tracers of the relative importance of individual N sources

Investigations on the transformation of N-fertilizer and the mineralization of organic N using 15N Pt. 1

International Nuclear Information System (INIS)

Latkovics, Gy.-ne

1979-01-01

A composting experiment was set up on chernozem-type brown forest soil to investigate the transformation of nitrogen fertilizer and the mineralization of organic N. For the average soil sample from the ploughed layer the pH value was 7.1, the mineral N content 2.85 mg, the fixed ammonium content 15.98 mg and the total N 140.8 mg100/g soil. The humus content was 1.91%. In the experiment 15 N labelled ammonium nitrate was used, and, as 15 N labelled organic matter, ground, air-dried rye-grass and bean stalks and with approximately the same N content as the 0.4% of the soil quantity measured. The values obtained by chemical methods and isotope indication show that the N-loss during composting was negligible and that the methods tested are suitable for the investigation of the transformation processes of nitrogen. (author)

Determination of the δ15N and δ18O of nitrate in solids; RSIL lab code 2897

Science.gov (United States)

Coplen, Tyler B.; Qi, Haiping; Revesz, Kinga; Casciotti, Karen; Hannon, Janet E.

2007-01-01

The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 2897 is to determine the δ15N and δ18O of nitrate (NO3-) in solids. The NO3- fraction of the nitrogen species is dissolved by water (called leaching) and can be analyzed by the bacterial method covered in RSIL lab code 2900. After leaching, the δ15N and δ18O of the dissolved NO3- is analyzed by conversion of the NO3- to nitrous oxide (N2O), which serves as the analyte for mass spectrometry. A culture of denitrifying bacteria is used in the enzymatic conversion of NO3- to N2O, which follows the pathway shown in equation 1: NO3- → NO2- → NO → 1/2 N2O (1) Because the bacteria Pseudomonas aureofaciens lack N2O reductive activity, the reaction stops at N2O, unlike the typical denitrification reaction that goes to N2. After several hours, the conversion is complete, and the N2O is extracted from the vial, separated from volatile organic vapor and water vapor by an automated -65 °C isopropanol-slush trap, a Nafion drier, a CO2 and water removal unit (Costech #021020 carbon dioxide absorbent with Mg(ClO4)2), and trapped in a small-volume trap immersed in liquid nitrogen with a modified Finnigan MAT (now Thermo Scientific) GasBench 2 introduction system. After the N2O is released, it is further purified by gas chromatography before introduction to the isotope-ratio mass spectrometer (IRMS). The IRMS is a Thermo Scientific Delta V Plus continuous flow IRMS (CF-IRMS). It has a universal triple collector, consisting of two wide cups with a narrow cup in the middle; it is capable of simultaneously measuring mass/charge (m/z) of the N2O molecule 44, 45, and 46. The ion beams from these m/z values are as follows: m/z = 44 = N2O = 14N14N16O; m/z = 45 = N2O = 14N15N16O or 14N14N17O; m/z = 46 = N2O = 14N14N18O. The 17O contributions to the m/z 44 and m/z 45 ion beams are accounted for before δ15N values are reported.

Metabolic studies in colostomized laying hens using 15N-labelled wheat. 4

International Nuclear Information System (INIS)

Gruhn, K.; Glotz, D.

1979-01-01

3 colostomized laying hybrids received over 4 days a dosage of 672 mg 15 N excess ( 15 N'), 20.3 mg lysine 15 N', 23.0 mg histidine 15 N' and 66.7 mg arginine 15 N' with a ration customary in production. After feeding the same unlabelled ration for another 4 days the hens were killed and the N content of the blood as well as of its fractions (cells, plasma, free amino acids of the plasma) was determined. The 15 N' was determined in the total blood, the corpuscles, the plasma, the nonprotein-N (NPN) fraction as well as in the amino acids lysine, histidine and arginine. The average amount of the blood cell N in the total blood N was 58.5% and that of the plasma 40.3%; the corresponding 15 N' values amounted to 66.1% and 33.9%, respectively. The sum of the 15 N' of the basic amino acids of the blood cells, on an average, amounted to 39.7% of the total cell 15 N'; the corresponding average value for the total 15 N' in lysine, histidine and arginine of the blood plasma 15 N' was 23.6.% and the quota of the three free amino acids of the total NP 15 N' of the plasma was 6.2%. (author)

Influence of organic N Sources on N transformation and uptake by lupine plants using 15N technique

International Nuclear Information System (INIS)

Abdel-Salam, A.A.; Gadalla, A.M.; Abdel- Aziz, H.A.; Galal, Y.G.M.; EL-degwy, S.M.

2008-01-01

A pot experiment was carried out under greenhouse conditions to evaluate the comparative efficiency and transformation of nitrogen applied either as mineral or organic forms. The obtained data showed that shoot dry weight was enhanced by compost and its mixture with leucaena. When organic sources were combined with 15 N, the leucaena.compost mixture (LC p ) gave the highest yield, and the other two were not significantly different from each other. Reinforcing the organic N with mineral N caused an average greater N.uptake over the non reinforced treatment. Similar trend was noticed with root system. Nitrogen uptake by roots was increased according to the order of LC > L > C. N derived from fertilizer (% Ndff) by lupine shoots was significantly affected by fertilizer addition either alone or reinforced with organic plant residues. Both, the portions (%) or absolute values (mg pot -1 ) of Ndff were increased by adding the organic residues. The highest value of Ndfs was recorded with application of leucaena followed by compost, then Leucaena + compost. Portion Ndfa reflected an effective response of lupines plants to Rhizobium inoculation. Addition of LC mixture combined with 15 N-fertilizer had enhanced the N 2 fixation and increased Ndfa value by about 66.7 % over those recorded with 15 N0 treatment. Organic amendment of leucaena could be an efficient source for N to infertile sandy soils

Flipped SU(5) predicts {delta}T/T

Energy Technology Data Exchange (ETDEWEB)

Kyae, Bumseok [School of Physics, Korea Institute for Advanced Study, 207-43, Cheongnyangni-Dong, Dongdaemun-Gu, Seoul 130-722 (Korea, Republic of)]. E-mail: bkyae@kias.re.kr; Shafi, Qaisar [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)]. E-mail: shafi@bartol.udel.edu

2006-04-20

We discuss hybrid inflation in supersymmetric flipped SU(5) model such that the cosmic microwave anisotropy {delta}T/T is essentially proportional to (M/M{sub P}){sup 2}, where M denotes the symmetry breaking scale and M{sub P} (=2.4x10{sup 18} GeV) is the reduced Planck mass. The magnitude of M determined from {delta}T/T measurements can be consistent with the value inferred from the evolution of SU(3) and SU(2) gauge couplings. In other words, one could state that flipped SU(5) predicts (more precisely 'postdicts') {delta}T/T. The scalar spectral index n{sub s}=0.993+/-0.007, the scalar to tensor ratio satisfies r-bar 10{sup -6}, while dn{sub s}/dlnk-bar 4x10{sup -4}.

Methodical investigation of the endogenous N excretion in feces by 15N-labelled rats

International Nuclear Information System (INIS)

Bergner, U.; Bergner, H.

1983-01-01

Wistar rats (approximately 100g live weight, n = 8) received a wheat diet and were labelled over a period of 7 days with 15 N-ammonium acetate. From day 1 - 5 of the experiment after the end of the labelling feces and urine were collected and analysed. After the animals were killed (day 5 of the experiment) the atom-% 15 N excess ( 15 N') in the contents of the digestive tract as well as in the tissues of stomach wall, intestinal wall, liver, pancreas and blood plasma was determined. The TCA-soluble fraction of the blood plasma showed 0.44 atom-% 15 N' on day 5 after the end of 15 N labelling. 3 hours before the killing fecal N also showed 0.44 and during the last collection period (24 hours before) an average of 0.51 atom-% 15 N'. Urine decreased in the same period from 0.71 to 0.59 atom-% 15 N'. The endogenous fecal N is calculated to 88%. As the tissues of the digestive tract are likely to supply the biggest part of the endogenous fecal protein, the values of atom-% 15 N' from the TCA-precipitable fraction of the intestinal wall and of the pancreas gland was calculed to an average of 0.526. According to this the calculation endogenous fecal N is 84%. It is probable that the quota of endogenous fecal N in the total amount of fecal N varies in dependence on the fermentable crude fiber in the diet as well as on the age of the test animals and thus the bacterial protein synthesis in the colon. As the N used by the bacteria is likely to come from the TCA-soluble fraction of the blood, the calculation formula suggested, which uses the TCA-soluble fraction of the blood plasma, achieves good approximate values also for higher bacterial protein synthesis in the colon. (author)

Fertilizer 15N balance and recovery of N from organic sources by rice in Typic Ustochrept

International Nuclear Information System (INIS)

Bhattacharyya, Ranjan; Sachdev, M.S.; Sachdev, P.; Kundu, S.; Sutradhar, G.

2002-01-01

To investigate the fertilizer-N balance and recovery of N from organics (as determined by A-value technique) by rice as affected by urea application alone or in combination with FYM or green manure, a field experiment was conducted in the khariff season if 1997 at IARI, New Delhi on a sandy loam soil (Typic Ustochrept). 15 N-labelled urea was applied at 0.90 and 120 kg N ha -1 levels alone and in combination with either FYM or green manure in 2:1 or 1:1 ratios. Organic sources were incorporated seven days before transplanting whereas, urea was applied in three equal splits at 15 DAT, 28 DAT and 42 DAT. The residual 15 N in soil was determined only in the surface soil layer (0-15 cm) of rice crop. The combined source helped in conserving more of urea-N in soil as residual (42-45%) than urea alone (23-27%) treatment due to the fact that the unaccounted fertilizer 15 N was more in urea alone treatment (43-45%) than combined sources (12-15%) at both the levels. The efficiency of uptake of organic N by rice as determined through A-value technique was similar or better than urea-N at both the levels. (author)

Comparison of (/sup 125/I)beta-endorphin binding to rat brain and NG108-15 cells using a monoclonal antibody directed against the opioid receptor

Energy Technology Data Exchange (ETDEWEB)

Bidlack, J.M.; O' Malley, W.E.; Schulz, R.

1988-02-01

The properties of (/sup 125/I)beta h-endorphin-binding sites from rat brain membranes and membranes from the NG108-15 cell line were compared using a monoclonal antibody directed against the opioid receptor and opioid peptides as probes. The binding of (/sup 125/I)beta h-endorphin to both rat brain and NG108-15 membranes yielded linear Scatchard plots with Kd values of 1.2 nM and 1.5 nM, respectively, and Bmax values of 865 fmol/mg rat brain membrane protein and 1077 fmol/mg NG108-15 membrane protein. A monoclonal antibody, OR-689.2.4, capable of inhibiting mu and delta binding but not kappa binding to rat brain membranes, noncompetitively inhibited the binding of 1 nM (/sup 125/I)beta h-endorphin to rat brain and NG108-15 membranes with an IC50 value of 405 nM for rat brain membranes and 543 nM for NG108-15 membranes. The monoclonal antibody also inhibited the binding of 3 nM (/sup 3/H) (D-penicillamine2, D-penicillamine5) enkephalin to NG108-15 membranes with an IC50 value of 370 nM. In addition to blocking the binding of (/sup 125/I)beta h-endorphin to brain membranes, the antibody also displaced (/sup 125/I)beta h-endorphin from membranes. Site-specific opioid peptides had large variations in their IC50 values depending on whether they were inhibiting (/sup 125/I)beta h-endorphin binding to rat brain or the NG108-15 membranes. When the peptides were tested with the monoclonal antibody for their combined ability to inhibit (/sup 125/I)beta h-endorphin binding to both membrane preparations, the peptides and antibody blocked binding as though they were acting at allosterically coupled sites, not two totally independent sites. These studies suggest that mu-, delta-, and beta-endorphin-binding sites share some sequence homology with the 35,000-dalton protein that the antibody is directed against.

15N-tomatine

International Nuclear Information System (INIS)

Elliger, C.A.

1988-01-01

A method for preparative isolation of 15 N-tomatine from foliage of tomato plants grown hydroponically with 15 N-containing nutrient salts is described. Extractive workup of plant material gave a crude product which was chromatographed on Sephadex LH-20 to yield pure tomatine. Assay of 15 N content by mass spectrometry showed that isotopic purity was ca. 95%. (author)

Anaerobic Transformation of Furfural by Methanococcus deltae (Delta)LH

Science.gov (United States)

Belay, N.; Boopathy, R.; Voskuilen, G.

1997-01-01

Methanococcus deltae (Delta)LH was grown on H(inf2)-CO(inf2) in the presence of various concentrations of furfural. Furfural at higher concentrations, namely, 20 and 25 mM, inhibited growth of this organism. At concentration of 5 and 10 mM, no inhibition of growth was observed. The other methanogens in this study were not inhibited by 10 mM furfural. Among the methanogens tested, M. deltae was capable of transforming furfural, whereas Methanobacterium thermoautotrophicum Marburg, Methanosarcina barkeri 227, Methanococcus thermolithotrophicus, and Methanobrevibacter ruminantium lacked this capability. One hundred percent removal of furfural was observed within 48 h of incubation in M. deltae cultures. The end product observed during furfural metabolism was furfuryl alcohol. An almost stoichiometric amount of furfuryl alcohol was produced by M. deltae. This transformation is likely to be of value in the detoxification of furfural and in its ultimate conversion to methane and CO(inf2) by anaerobic digestion. PMID:16535618

Variable δ15N Diet-Tissue Discrimination Factors among Sharks: Implications for Trophic Position, Diet and Food Web Models

Science.gov (United States)

Olin, Jill A.; Hussey, Nigel E.; Grgicak-Mannion, Alice; Fritts, Mark W.; Wintner, Sabine P.; Fisk, Aaron T.

2013-01-01

The application of stable isotopes to characterize the complexities of a species foraging behavior and trophic relationships is dependent on assumptions of δ15N diet-tissue discrimination factors (∆15N). As ∆15N values have been experimentally shown to vary amongst consumers, tissues and diet composition, resolving appropriate species-specific ∆15N values can be complex. Given the logistical and ethical challenges of controlled feeding experiments for determining ∆15N values for large and/or endangered species, our objective was to conduct an assessment of a range of reported ∆15N values that can hypothetically serve as surrogates for describing the predator-prey relationships of four shark species that feed on prey from different trophic levels (i.e., different mean δ15N dietary values). Overall, the most suitable species-specific ∆15N values decreased with increasing dietary-δ15N values based on stable isotope Bayesian ellipse overlap estimates of shark and the principal prey functional groups contributing to the diet determined from stomach content analyses. Thus, a single ∆15N value was not supported for this speciose group of marine predatory fishes. For example, the ∆15N value of 3.7‰ provided the highest percent overlap between prey and predator isotope ellipses for the bonnethead shark (mean diet δ15N = 9‰) whereas a ∆15N value white shark (mean diet δ15N = 15‰). These data corroborate the previously reported inverse ∆15N-dietary δ15N relationship when both isotope ellipses of principal prey functional groups and the broader identified diet of each species were considered supporting the adoption of different ∆15N values that reflect the predators’ δ15N-dietary value. These findings are critical for refining the application of stable isotope modeling approaches as inferences regarding a species’ ecological role in their community will be influenced with consequences for conservation and management actions. PMID:24147026

In-situ Kd values and geochemical behavior for inorganic and organic constituents of concern at the TNX Outfall Delta

International Nuclear Information System (INIS)

Kaplan, D.I.

2000-01-01

A series of tests were conducted to provide site-specific Kd values for constituents of concern at the TNX Outfall Delta Operable Unit. These Kd values can be used to calculate contaminant migration within the operable unit and are, at this time considered to be the most defensible values

Use of 15N in evaluating symbiotic N2 fixation of field-grown soybeans

International Nuclear Information System (INIS)

Ham, G.E.

1978-01-01

Various methods have been used to estimate N 2 fixation by legumes (i.e. Kjeldahl N and the acetylene-ethylene assay). Recently 'Asub(N)' values by the legume and a non-nodulating crop using 15 N-labelled N fertilizer were used to quantitatively estimate the amount of N 2 fixed by legume crops growing under field conditions. The objective of this research was to evaluate Kjeldahl N procedures, the acetylene-ethylene assay and the 'Asub(N)' technique as estimators of N 2 fixation by field-grown soybeans. The 'Asub(N)' value concept provided a reliable estimate of N 2 fixation by soybeans which agreed with acetylene-ethylene measurements made weekly and the values compared favourably with Kjeldahl N measurements. (author)

Financial Performance of Hospitals in the Mississippi Delta Region Under the Hospital Readmissions Reduction Program and Hospital Value-based Purchasing Program.

Science.gov (United States)

Chen, Hsueh-Fen; Karim, Saleema; Wan, Fei; Nevola, Adrienne; Morris, Michael E; Bird, T Mac; Tilford, J Mick

2017-11-01

Previous studies showed that the Hospital Readmissions Reduction Program (HRRP) and the Hospital Value-based Purchasing Program (HVBP) disproportionately penalized hospitals caring for the poor. The Mississippi Delta Region (Delta Region) is among the most socioeconomically disadvantaged areas in the United States. The financial performance of hospitals in the Delta Region under both HRRP and HVBP remains unclear. To compare the differences in financial performance under both HRRP and HVBP between hospitals in the Delta Region (Delta hospitals) and others in the nation (non-Delta hospitals). We used a 7-year panel dataset and applied difference-in-difference models to examine operating and total margin between Delta and non-Delta hospitals in 3 time periods: preperiod (2008-2010); postperiod 1 (2011-2012); and postperiod 2 (2013-2014). The Delta hospitals had a 0.89% and 4.24% reduction in operating margin in postperiods 1 and 2, respectively, whereas the non-Delta hospitals had 1.13% and 1% increases in operating margin in postperiods 1 and 2, respectively. The disparity in total margins also widened as Delta hospitals had a 1.98% increase in postperiod 1, but a 0.30% reduction in postperiod 2, whereas non-Delta hospitals had 1.27% and 2.28% increases in postperiods 1 and 2, respectively. The gap in financial performance between Delta and non-Delta hospitals widened following the implementation of HRRP and HVBP. Policy makers should modify these 2 programs to ensure that resources are not moved from the communities that need them most.

Evaluation of natural 15N abundance method in estimating symbiotic dinitrogen fixation by leguminous grasses

International Nuclear Information System (INIS)

Yao Yunyin; Cheng Ming; Ma Changlin; Wang Zhidong; Hou Jinqin; Zhang Lihong; Luo Yongyun

1991-01-01

Natural 15 N abundance method was used to estimate contribution of symbiotic dinitrogen fixation by leguminous grasses. With the method the expensive 15 N fertilizer did not need to be applied to the soil and the normal ecosystem was not disturbed. Collecting samples of shoots of leguminous grasses and measuring the content of 15 N in them wee all to do for estimating potential of symbiotically fixed N 2 . Isotopic fractionation associated with N 2 fixation by legumes was studied. Values for 7 cultivars of alfalfa were ranged between 1.0000 ∼ 1.0015 (δ 15 N values were -0.05 ∼ 1.47 per mille); and the values for white clover, mung bean and whitepopinac lead tree were 0.0079, 0.9983 and 1.0018 (δ 15 N values: 2.15, 1.74 and -1.81 per mille) respectively. According to the δ 15 N values of grasses tested, the potential of N 2 fixation for 6 cultivars of alfalfa was estimated. Glory and rambler had higher potential of N 2 fixation; Baoding, Aigonquin and Minto had lower potential, and Peru was the lowest.N 2 fixing activity of alfalfa varied with different periods. The peak was found between June and July. Effects of non-N 2 -fixing references and different methods on estimates of %Ndfa of leguminous grasses were also discussed

( sup 3 H)(D-PEN sup 2 , D-PEN sup 5 ) enkephalin binding to delta opioid receptors on intact neuroblastoma-glioma (NG 108-15) hybrid cells

Energy Technology Data Exchange (ETDEWEB)

Knapp, R.J.; Yamamura, H.I. (Univ. of Arizona College of Medicine, Tucson (USA))

1990-01-01

({sup 3}H)(D-Pen{sup 2}, D-Pen{sup 5})enkephalin binding to intact NG 108-15 cells has been measured under physiological conditions of temperature and medium. The dissociation constant, receptor density, and Hill slope values measured under these conditions are consistent with values obtained by others using membranes prepared from these cells. Kinetic analysis of the radioligand binding to these cells show biphasic association and monophasic dissociation processes suggesting the presence of different receptor affinity states for the agonist. The data show that the binding affinity of ({sup 3}H)(D-Pen{sup 2}, D-Pen{sup 5})enkephalin under physiological conditions is not substantially different to that measured in 50 mM Tris buffer using cell membrane fractions. Unlike DPDPE, the {mu} opioid agonists morphine, normorphine, PL-17, and DAMGO, have much lower affinity for the {delta} receptor measured under these conditions than is observed by studies using 50 mM Tris buffer. The results described here suggest that this assay may serve as a useful model of {delta} opioid receptor binding in vivo.

Estimation of water transit time in soils under Amazon forest cover using variations in delta18O values

International Nuclear Information System (INIS)

Leopoldo, P.R.; Matsui, E.; Salati, E.

1984-01-01

The work was carried out at the forest reserve of the Instituto Nacional de Pesquisas da Amazonia, located at km 45 of Manaus, in an area characterized by Amazon vegetation of the 'terra-firme' type. To extract the soil water, four soil-water collecting stations were installed, and in each the porous cups were placed at 15, 25, 50, 80 and 120 cm depth from the soil surface. The rain-water and soil-water samples were collected only weekly for analysis of the 18 O content. In an attempt to estimate the soil-water transit time using the variation in 18 O values, a statistical model was used. This model is based on linear regression analysis applied to the values observed for soil water and rain water. From this analysis, regression coefficients are obtained which vary according to time. The values of the coefficients obtained can be adjusted generally, according to a quadratic regression, with the maximum value of the function representing the time in which the best statistical correlation between the observed delta 18 O values occurs. The time obtained from these correlations represents the mean time necessary for the water to run from one collecting point to the next. (author)

Constraints on oceanic N balance/imbalance from sedimentary 15N records

Directory of Open Access Journals (Sweden)

M. A. Altabet

2007-01-01

Full Text Available According to current best estimates, the modern ocean's N cycle is in severe deficit. N isotope budgeting provides an independent geochemical constraint in this regard as well as the only means for past reconstruction. Overall, it is the relative proportion of N2 fixation consumed by water column denitrification that sets average oceanic δ15N under steady-state conditions. Several factors (conversion of organic N to N2, Rayleigh closed and open system effects likely reduce the effective fractionation factor (ε for water column denitrification to about half the inherent microbial value for εden. If so, the average oceanic δ15N of ~5‰ is consistent with a canonical contribution from water column denitrification of 50% of the source flux from N2 fixation. If an imbalance in oceanic N sources and sinks changes this proportion then a transient in average oceanic δ15N would occur. Using a simple model, changing water column denitrification by ±30% or N2 fixation by ±15% produces detectable (>1‰ changes in average oceanic δ15N over one residence time period or more with corresponding changes in oceanic N inventory. Changing sedimentary denitrification produces no change in δ15N but does change N inventory. Sediment δ15N records from sites thought to be sensitive to oceanic average δ15N all show no detectible change over the last 3 kyr or so implying a balanced marine N budget over the latest Holocene. A mismatch in time scales is the most likely meaningful interpretation of the apparent conflict with modern flux estimates. Decadal to centennial scale oscillations between net N deficit and net surplus may occur but on the N residence timescale of several thousand years, net balance is achieved in sum. However, sediment δ15N records from the literature covering the period since the last glacial maximum show excursions of up to several ‰ that are consistent with sustained N deficit during the deglaciation followed by readjustment

Comparison of polarization and analyzing power for the /sup 15/N(p,n)/sup 15/O reaction

Energy Technology Data Exchange (ETDEWEB)

Byrd, R.C.; Tornow, W.; Lisowski, P.W.; Murphy, K.; Walter, R.L. (Duke Univ., Durham, NC (USA). Dept. of Physics; Triangle Universities Nuclear Lab., Durham, NC (USA))

1983-11-21

The analyzing power Asub(y)(theta) and polarization Psup(y)(theta) for the /sup 15/N(p,n/sub 0/)/sup 15/O reaction have been measured for Esub(p)=4.5-11.3 MeV. The values of the two observables are nearly the same above 11 MeV, where a ''quasi-elastic'' view of the (p,n) reaction to the analog state should be applicable. Below 10 MeV, however, large spin-flip amplitudes and isospin-mixing ratios provide the two major conditions needed to obtain Psup(y)(theta)not=Asub(y)(theta) and dramatic differences between the two observables are observed. The size of the differences and their dependence on energy are similar to the results predicted by shell-model calculations. The Psup(y)(theta) and Asub(y)(theta) measurements have been combined with existing cross-section data to provide information about spin-flip processes. We also comment on the connection between comparisons of Psup(y)(theta) and Asup(y)(theta) in charge-symmetric (p,n) reactions and the recent controversial measurements of a difference between the values of Psup(y)(theta) for a reaction and Asub(y)(theta) for the inverse reaction.

Isotopologue fractionation during N(2)O production by fungal denitrification.

Science.gov (United States)

Sutka, Robin L; Adams, Gerard C; Ostrom, Nathaniel E; Ostrom, Peggy H

2008-12-01

Identifying the importance of fungi to nitrous oxide (N2O) production requires a non-intrusive method for differentiating between fungal and bacterial N2O production such as natural abundance stable isotopes. We compare the isotopologue composition of N2O produced during nitrite reduction by the fungal denitrifiers Fusarium oxysporum and Cylindrocarpon tonkinense with published data for N2O production during bacterial nitrification and denitrification. The fractionation factors for bulk nitrogen isotope values for fungal denitrification were in the range -74.7 to -6.6 per thousand. There was an inverse relationship between the absolute value of the fractionation factors and the reaction rate constant. We interpret this in terms of variation in the relative importance of the rate constants for diffusion and enzymatic reduction in controlling the net isotope effect for N2O production during fungal denitrification. Over the course of nitrite reduction, the delta(18)O values for N2O remained constant and did not exhibit a relationship with the concentration characteristic of an isotope effect. This probably reflects isotopic exchange with water. Similar to the delta(18)O data, the site preference (SP; the difference in delta(15)N between the central and outer N atoms in N2O) was unrelated to concentration during nitrite reduction and, therefore, has the potential to act as a conservative tracer of production from fungal denitrification. The SP values of N2O produced by F. oxysporum and C. tonkinense were 37.1 +/- 2.5 per thousand and 36.9 +/- 2.8 per thousand, respectively. These SP values are similar to those obtained in pure culture studies of bacterial nitrification but quite distinct from SP values for bacterial denitrification. The large magnitude of the bulk nitrogen isotope fractionation and the delta(18)O values associated with fungal denitrification are distinct from bacterial production pathways; thus multiple isotopologue data holds much promise for

Ultra-violet absorption cross sections of isotopically substituted nitrous oxide species: 14N14NO, 15N14NO, 14N15NO and 15N15NO

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P. von Hessberg

2004-01-01

Full Text Available The isotopically substituted nitrous oxide species 14N14NO, 15N14NO, 14N15NO and 15N15NO were investigated by ultra-violet (UV absorption spectroscopy. High precision cross sections were obtained for the wavelength range 181 to 218nm at temperatures of 233 and 283K. These data are used to calculate photolytic isotopic fractionation constants as a function of wavelength. The fractionation constants were used in a three-dimensional chemical transport model in order to simulate the actual fractionation of N2O in the stratosphere, and the results were found to be in good agreement with field studies.

Food-web structure of seep sediment macrobenthos from the Gulf of Mexico

Science.gov (United States)

Demopoulos, Amanda W.J.; Gualtieri, Daniel; Kovacs, Kaitlin

2010-01-01

The slope environment of the Gulf of Mexico (GOM) supports dense communities of seep megafaunal invertebrates that rely on endosymbiotic bacteria for nutrition. Seep sediments also contain smaller macrofaunal invertebrates whose nutritional pathways are not well understood. Using stable-isotope analysis, we investigate the utilization of chemosynthetically fixed and methane-derived organic matter by macrofauna. Biological sampling was conducted in three lower-slope GOM seep environs: Green Canyon (GC852, 1428 m), Atwater Valley (AT340, 2230 m), and Alaminos Canyon (AC601, 2384 m). Infaunal delta13C and delta15N exhibited a broad range of values; most infauna appeared to be heterotrophic, although several taxa had very light delta15N and delta13C values, indicating possible reliance on chemoautotrophic symbioses. The lightest delta13C and delta15N values were observed in nematodes (delta13C=-54.6 + or - 0.1 per mil, delta15N=-6.1 + or - 0.2 per mil) and one gastropod (delta13C=-54.1 per mil, delta15N=-1.1 per mil) from Green Canyon. Mixing-model results indicated that sulfur-oxidizing Beggiatoa may be an important food source for seep infauna; the rate of utilization ranged from 60% to 100% at Green Canyon and Atwater Valley. The overall range in isotope values was similar across the three sites, suggesting that biogeochemical processes may be very similar in these geographically distinct areas.

Yields, market values and n use efficiency in flue-cured tobacco influenced by time of basal n fertilization

International Nuclear Information System (INIS)

Xie Zhijian; Tu Shuxin; Li Jinping; Xu Rubing; Chen Zhenguo; Wang Xuelong

2010-01-01

A field experiment with 15 N isotope tracing micro-plots was carried out to study the effects of basal N fertilizer application time (0 d, 15 d, 30 d before the transplanting) on the yields, market values and N uptake, utilization and distribution in different organs of flue-cured tobacco (FCT) in two ecological tobacco production areas (Zhaojiashan and Laowan) of Xiangfan City, Hubei Province. The results showed that supplying N fertilizer significantly increased the yields and market values of FCT by 13% ∼ 40% and 14% ∼ 35% for the experimental site of Zhaojiashan (lower altitude) and Laowan (higher altitude), respectively. Compared to applying basal fertilizer at 0 d before transplanting, applying basal fertilizer at 15 d or 30 d before transplanting increased the market values by 10% ∼ 30% (P < 0.05). And early application of basal N fertilizer (30 d before transplanting) increased N accumulation by 8% ∼ 26% as compared with that of applying basal N fertilizer at 0 d or 15 d before transplanting in the two ecological areas. There was no significant effects of basal N application time on N fertilizer efficiency in lower altitude site, but increasing by 3% ∼ 6% in higher altitude site. These results indicated that properly earlier (15 d for example) supplication of basal N fertilizer could improve the N fertilizer efficiency, and thus increase the yields and market values of FCT, especially in higher altitude areas with less sunshine and lower temperature. (authors)

Variable δ(15N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models.

Directory of Open Access Journals (Sweden)

Jill A Olin

Full Text Available The application of stable isotopes to characterize the complexities of a species foraging behavior and trophic relationships is dependent on assumptions of δ(15N diet-tissue discrimination factors (∆(15N. As ∆(15N values have been experimentally shown to vary amongst consumers, tissues and diet composition, resolving appropriate species-specific ∆(15N values can be complex. Given the logistical and ethical challenges of controlled feeding experiments for determining ∆(15N values for large and/or endangered species, our objective was to conduct an assessment of a range of reported ∆(15N values that can hypothetically serve as surrogates for describing the predator-prey relationships of four shark species that feed on prey from different trophic levels (i.e., different mean δ(15N dietary values. Overall, the most suitable species-specific ∆(15N values decreased with increasing dietary-δ(15N values based on stable isotope Bayesian ellipse overlap estimates of shark and the principal prey functional groups contributing to the diet determined from stomach content analyses. Thus, a single ∆(15N value was not supported for this speciose group of marine predatory fishes. For example, the ∆(15N value of 3.7‰ provided the highest percent overlap between prey and predator isotope ellipses for the bonnethead shark (mean diet δ(15N = 9‰ whereas a ∆(15N value < 2.3‰ provided the highest percent overlap between prey and predator isotope ellipses for the white shark (mean diet δ(15N = 15‰. These data corroborate the previously reported inverse ∆(15N-dietary δ(15N relationship when both isotope ellipses of principal prey functional groups and the broader identified diet of each species were considered supporting the adoption of different ∆(15N values that reflect the predators' δ(15N-dietary value. These findings are critical for refining the application of stable isotope modeling approaches as inferences regarding a species

[Studies with 15N-labeled lysine in colostomized hens. 2. 15N excretion in feces].

Science.gov (United States)

Gruhn, K; Wiefel, P

1983-05-01

Over a period of four days colostomised hens were given 15N-lysine, and the development of 15N-excretion both in the TCA-soluble and the TCA-precipitable fraction of the faeces was measured over eight days. In both fractions the total, lysine, histidine and arginine N and 15N-excess (15N') was determined. The average apparent digestibility of 14N was 81.2% +/- 1.1% and of 15N' 93.2% +/- 0.7%. Labelled N is already excreted in faeces 3 hours after its application. The TCA-precipitable N is less strongly labelled than the TCA-soluble N. During the application of 15N' the labelling in faecal lysine is nearly one power of ten higher than in total N. The atom-% 15N' of the lysine could also be distinctly detected in arginine and histidine. The quotas of the total 15N' in faeces were 3.5% for arginine-15N' and 0.8% for histidine 15N'; 15N' can mainly be detected in the soluble fraction.

A liver-function test using 15N-labelled ammonium chloride

International Nuclear Information System (INIS)

Jung, K.; Hirscherg, K.; Faust, H.; Matkowitz, R.

1985-01-01

Malfunction of the liver involves disturbances of urea synthesis and ammonia detoxification. These phenomena became apparent, especially during ammonia loading of patients. The functional state of the liver can be assessed by oral administration of 15 NH 4 Cl and subsequent analysis of 15 N-urea and 15 N-ammonia in urine by emission spectrometry. Clinical tests based on the ratio of the excess abundances (see Appendix) of 15 N-ammonia to 15 N-urea excreted in urine 3 h after oral administration gave values for patients with liver disease which differed significantly from those for healthy subjects. Absorption disturbances, which often accompany liver diseases, do not influence the effectiveness of the method. (orig.)

Liver-function test using /sup 15/N-labelled ammonium chloride

Energy Technology Data Exchange (ETDEWEB)

Jung, K; Hirscherg, K; Faust, H; Matkowitz, R

1985-08-01

Malfunction of the liver involves disturbances of urea synthesis and ammonia detoxification. These phenomena became apparent, especially during ammonia loading of patients. The functional state of the liver can be assessed by oral administration of /sup 15/NH/sub 4/Cl and subsequent analysis of /sup 15/N-urea and /sup 15/N-ammonia in urine by emission spectrometry. Clinical tests based on the ratio of the excess abundances (see Appendix) of /sup 15/N-ammonia to /sup 15/N-urea excreted in urine 3 h after oral administration gave values for patients with liver disease which differed significantly from those for healthy subjects. Absorption disturbances, which often accompany liver diseases, do not influence the effectiveness of the method.

Density and viscosity of aqueous solutions of N,N-dimethylethanolamine at p = 0.1 MPa from T = (293.15 to 363.15) K

Energy Technology Data Exchange (ETDEWEB)

Bernal-Garcia, J. Manuel [Instituto Mexicano del Petroleo, Mexico D.F. C.P. 07330 (Mexico); Hall, Kenneth R. [Chemical Engineering Department, Texas A and M University, College Station, TX 77843 (United States); Estrada-Baltazar, Alejandro [Departamento de Ingenieria Quimica, Instituto Tecnologico de Celaya, Celaya, Guanajuato, CP 38010 (Mexico); Iglesias-Silva, Gustavo A. [Departamento de Ingenieria Quimica, Instituto Tecnologico de Celaya, Celaya, Guanajuato, CP 38010 (Mexico)]. E-mail: gais@iqcelaya.itc.mx

2005-08-15

This work presents atmospheric density and viscosity values for (N,N-dimethylethanolamine + water) over the entire composition range from T (293.15 to 363.15) K for density and from T = (313.15 to 353.15) K for viscosity. Density measurements come from a vibrating tube densimeter while we have used three different Cannon-Fenske viscosimeters for the viscosity measurements. Excess molar volumes and viscosity deviations are calculated using a Redlich-Kister type equation. Excess molar volumes present negative deviations from ideality and viscosity deviations are positive at all temperatures and compositions in this work.

Density and viscosity of aqueous solutions of N,N-dimethylethanolamine at p = 0.1 MPa from T = (293.15 to 363.15) K

International Nuclear Information System (INIS)

Bernal-Garcia, J. Manuel; Hall, Kenneth R.; Estrada-Baltazar, Alejandro; Iglesias-Silva, Gustavo A.

2005-01-01

This work presents atmospheric density and viscosity values for (N,N-dimethylethanolamine + water) over the entire composition range from T (293.15 to 363.15) K for density and from T = (313.15 to 353.15) K for viscosity. Density measurements come from a vibrating tube densimeter while we have used three different Cannon-Fenske viscosimeters for the viscosity measurements. Excess molar volumes and viscosity deviations are calculated using a Redlich-Kister type equation. Excess molar volumes present negative deviations from ideality and viscosity deviations are positive at all temperatures and compositions in this work

Utilization of dE/dx approx E sup n /a dependence for DELTA E - E-spectrometer calibration

CERN Document Server

Gorpinich, O K; Jachmenov, O O

2002-01-01

The method of calibration of DELTA E - E-spectrometers by the use of known empiric form dE/dx approx E sup n /a which describes the specific energy loss of charge particles in the matter for energy calibration of DELTA E - E-spectrometer was designed.

Nitrogen-15 natural abundance of different soil N pools as a tool for assessing N transformation processes in alpine soils

Science.gov (United States)

Makarov, Mikhail; Malysheva, Tatiana; Tiunov, Alexei; Kadulin, Maxim; Maslov, Mikhail

2017-04-01

Nitrogen availability, net N mineralization, nitrification and 15N natural abundance of total soil N and small soil N pools (N-NH4+, N-NO3-, DON and microbial biomass N) were studied in a toposequence of alpine ecosystems in the Northern Caucasus. The toposequence was represented by (1) low productive alpine lichen heath (ALH) of the wind-exposed ridge and upper slope; (2) more productive Festuca varia grassland (FG) of the middle slope; (3) most productive Geranium gymnocaulon/Hedysarum caucasicum meadow (GHM) of the lower slope and (4) low productive snow bed community (SBC) of the slope bottom. Nitrogen transformation in the alpine soils produces distinct N pools with different 15N enrichment: DON/microbial biomass N > total N > N-NH4+ > N-NO3-. Grassland and meadow soils of the middle part of the toposequence are characterized by higher nitrogen transformation activities and higher δ15 values of total N and N-NH4+. Field incubation of alpine soils increased δ15N of N-NH4+ from -2.6 - +2.0‰ to +6.1 - +15.7‰. The N-NO3-produced in the incubation experiment had extremely low (negative) δ15N values (up to -14‰). We found a positive correlation between δ15N of different soil N pools (total N, N-NH4+ and N-NO3-) and net N mineralization and nitrification. Nitrification controls the formation of 15N enriched N-NH4+ pool while N mineralization probably had an important role in regulation of 15N enrichment of DON pool in alpine soils. Overall, our results support the hypothesis that 15N is more enriched in N-rich and more depleted in N-poor ecosystems. We conclude that δ15N values of different soil N pools could be a good indicator of microbial N transformation in alpine soils of the Northern Caucasus. Acknowledgement: This study was supported by Russian Science Foundation (16-14-10208).

Optimality and self-organization in river deltas

Science.gov (United States)

Tejedor, A.; Longjas, A.; Edmonds, D. A.; Zaliapin, I. V.; Georgiou, T. T.; Rinaldo, A.; Foufoula-Georgiou, E.

2017-12-01

Deltas are nourished by channel networks, whose connectivity constrains, if not drives, the evolution, functionality and resilience of these systems. Understanding the coevolution of deltaic channels and their flux organization is crucial for guiding maintenance strategies of these highly stressed systems from a range of anthropogenic activities. However, in contrast to tributary channel networks, to date, no theory has been proposed to explain how deltas self-organize to distribute water and sediment to the delta top and the shoreline. Here, we hypothesize the existence of an optimality principle underlying the self-organized partition of fluxes in delta channel networks. Specifically, we hypothesize that deltas distribute water and sediment fluxes on a given delta topology such as to maximize the diversity of flux delivery to the shoreline. By introducing the concept of nonlocal Entropy Rate (nER) and analyzing ten field deltas in diverse environments, we present evidence that supports our hypothesis, suggesting that delta networks achieve dynamically accessible maxima of their nER. Furthermore, by analyzing six simulated deltas using the Delf3D model and following their topologic and flux re-organization before and after major avulsions, we further study the evolution of nER and confirm our hypothesis. We discuss how optimal flux distributions in terms of nER, when interpreted in terms of resilience, are configurations that reflect an increased ability to withstand perturbations.

Thermal expansion of superconducting phases Bi sub 2 Sr sub 2 Ca sub n-1 Cu sub n O sub 2n+2+. delta. with n=1,2,3. Termicheskoe rasshirenie sverkhprovodyashchikh faz Bi sub 2 Sr sub 2 Ca sub n-1 Cu sub n O sub 2n+2+. delta. s n=1,2,3

Energy Technology Data Exchange (ETDEWEB)

Zhurov, V V; Ivanov, S A [Nauchno-Issledovatel' skij Fiziko-Khimicheskij Inst., Moscow (USSR); Bush, A A; Romanov, B N [Moskovskij Inst. Radiotekhniki, Ehlektroniki i Avtomatiki, Moscow (USSR)

1990-10-01

Consideration is given to results of X-ray diffraction studies of temperature dependences of a{sub 0},c{sub 0} sublattice parameters of Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+2+}{delta} superconducting phases with n=1,2,3 (2201, 2212, 2223) in 90-1000 K range. The obtained dependences are composed of some temperature linear sections, where values of thermal coefficients of linear expansion {alpha}{sub a}, {alpha}{sub c} were determined for all examined phases. During first heating of samples of 2212 phase a{sub 0}(T), c{sub 0}(T) dependences deviate in {approx equal}500-700 K range from linear ones till the occurence of a section with negative a{sub c}. After heating of 2212 phase up to T>{approx equal}700 K and cooling down to 300 K, a{sub 0},c{sub 0} parameters decrease by {approx equal}0.006 and 0.08 A respectively. Data on the effect of preparation method and thermal prehistory of 2212 samples and on relative content of calcium atoms in them for these anomalies were obtained. Some possible reasons of their occurence were analyzed.

2007 California Aerosol Study: Evaluation of δ15N as a Tracer Of NOx Sources and Chemsitry

Science.gov (United States)

Katzman, T. L.

2017-12-01

Although stable isotopes of N are commonly used as a source tracer, how this tracer is applied is a point of contention. The "source" hypothesis argues that the δ15N value of NO3- reflects the δ15N value of NOx source inputs into the environment, and any observed variation is solely the result of differences in source contributions. Conversely, the "chemistry" hypothesis argues that N isotopes are influenced by chemical reactions, atmospheric or biologic processing, and post-depositional effects. Previous studies often apply the source hypothesis, writing off the chemistry hypothesis as "minor," but others have noted the impact chemistry should has on δ15N values. Given the known complications, this work seeks to assess the use of stable isotopes as tracers, specifically, the assumption that the δ15N value is a tracer of source alone without significant influence from chemical reactions. If the "source" hypothesis is correct, source emission data, known source δ15N values, and isotope mass balance should be able to approximate measured δ15NNO3 values and determine the δ15N value associated with wildfire derived NOx, which is currently unknown. Significant deviations from observed values would support the significance of equilibrium and kinetic isotope effects associated with chemical reactions and processing in the atmosphere. Aerosols collected in during 2007, emission data, and isotopic analysis were utilized to determine the utility of δ15N as tracer of NOx sources. San Diego, California is a coastal urban area influenced by sea salt aerosols, anthropogenic combustion emissions, and seasonal wildfires. Wildfires also have a significant influence on local atmospheric chemistry and 2007 was notable for being one of the worst fire seasons in the San Diego region on record. Isotopic analysis of collected NO3- has suggested that source δ15N values are likely not conserved as NOx is oxidized into NO3-. Given known source contributions and known δ15N values

Feeding ecology of pelagic fish larvae and juveniles in slope waters of the Gulf of Mexico.

Science.gov (United States)

Wells, R J D; Rooker, J R

2009-11-01

Stable isotope ratios of carbon (delta13C) and nitrogen (delta15N) were used to investigate feeding patterns of larval and early juvenile pelagic fishes in slope waters of the Gulf of Mexico. Contribution of organic matter supplied to fishes and trophic position within this pelagic food web was estimated in 2007 and 2008 by comparing dietary signatures of the two main producers in this ecosystem: phytoplankton [based on particulate organic matter (POM)] and Sargassum spp. Stable isotope ratios of POM and pelagic Sargassum spp. were significantly different from one another with delta13C values of POM depleted by 3-6 per thousand and delta15N values enriched by 2 relative to Sargassum spp. Stable isotope ratios were significantly different among the five pelagic fishes examined: blue marlin Makaira nigricans, dolphinfish Coryphaena hippurus, pompano dolphinfish Coryphaena equiselis, sailfish Istiophorus platypterus and swordfish Xiphias gladius. Mean delta13C values ranged almost 2 among fishes and were most depleted in I. platypterus. In addition, mean delta15N values ranged 4-5 with highest mean values found for both C. hippurus and C. equiselis and the lowest mean value for M. nigricans during both years. Increasing delta13C or delta15N with standard length suggested that shifts in trophic position and diet occurred during early life for several species examined. Results of a two-source mixing model suggest approximately an equal contribution of organic matter by both sources (POM=55%; pelagic Sargassum spp.=45%) to the early life stages of pelagic fishes examined. Contribution of organic matter, however, varied among species, and sensitivity analyses indicated that organic source estimates changed from 2 to 13% for a delta(13)C fractionation change of +/-0.25 per thousand or a delta15N fractionation change of +/-1.0 per thousand relative to original fractionation values.

Asymptotic normalization coefficients for 14N+p→15O and the astrophysical S factor for 14N(p,γ)15O

International Nuclear Information System (INIS)

Mukhamedzhanov, A.M.; Gagliardi, C.A.; Pirlepesov, F.; Tribble, R.E.; Bem, P.; Burjan, V.; Kroha, V.; Novak, J.; Piskor, S.; Simeckova, E.; Vincour, J.; Brown, B.A.; Nunes, F.M.

2003-01-01

The 14 N(p,γ) 15 O reaction, which controls energy production in the CNO cycle, has contributions from both resonance and direct captures to the ground and excited states. The overall normalization of the direct captures is defined by the corresponding asymptotic normalization coefficients (ANCs). Especially important is the ANC for the subthreshold state in 15 O at -0.504 keV since direct capture through this state dominates the reaction rate at stellar energies. In order to determine the ANCs for 14 N+p→ 15 O, the 14 N( 3 He,d) 15 O proton transfer reaction has been measured at an incident energy of 26.3 MeV. Angular distributions for proton transfer to the ground and five excited states were obtained. ANCs were then extracted from comparison to both distorted-wave Born approximation and coupled-channels Born approximation calculations. Using these ANCs, we calculated the astrophysical factor and reaction rates for 14 N(p,γ) 15 O. Our analysis favors a low value for the astrophysical factor

On the experimental value of the DELTA sup + (1232) mass from gamma p -> n pi sup + (p suppi sup 0) reactions

CERN Document Server

Omelaenko, A S

2002-01-01

The reliability of the phenomenological estimates for the DELTA sup + (1232) mass is questioned coming from the of pi sup + and pi sup 0 mesons photoproduction data off proton target till the end of 2001. The origin of an old discrepancy for the DELTA sup + (1232) mass presented in tables of the Particle Data Group is discussed.

Isotopic ratios D/H and 15N/14N in giant planets

Science.gov (United States)

Marboeuf, Ulysse; Thiabaud, Amaury; Alibert, Yann; Benz, Willy

2018-04-01

The determination of isotopic ratios in planets is important since it allows us to investigate the origins and initial composition of materials. The present work aims to determine the possible range of values for isotopic ratios D/H and 15N/14N in giant planets. The main objective is to provide valuable theoretical assumptions on the isotopic composition of giant planets, their internal structure, and the main reservoirs of species. We use models of ice formation and planet formation that compute the composition of ices and gas accreted in the core and the envelope of planets. Assuming a single initial value for isotopic ratios in volatile species, and disruption of planetesimals in the envelope of gaseous planets, we obtain a wide variety of D/H and 15N/14N ratios in low-mass planets (≤100 Mearth) due to the migration pathway of planets, the accretion time of gas species whose relative abundance evolves with time, and isotope exchanges among species. If giant planets with mass greater than 100 Mearth have solar isotopic ratios such as Jupiter and Saturn due to their higher envelope mass, Neptune-type planets present values ranging between one and three times the solar value. It seems therefore difficult to use isotopic ratios in the envelope of these planets to get information about their formation in the disc. For giant planets, the ratios allow us to constrain the mass fraction of volatile species in the envelope needed to reproduce the observational data by assuming initial values for isotopic ratios in volatile species.

15N/14N isotopic ratio and statistical analysis: an efficient way of linking seized Ecstasy tablets

International Nuclear Information System (INIS)

Palhol, Fabien; Lamoureux, Catherine; Chabrillat, Martine; Naulet, Norbert

2004-01-01

In this study, the 15 N/ 14 N isotopic ratios of 106 samples of 3,4-methylenedioxymethamphetamine (MDMA) extracted from Ecstasy tablets are presented. These ratios, measured using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS), show a large discrimination between samples with a range of δ 15 N values between -17 and +19%o, depending on the precursors and the method used in clandestine laboratories. Thus, δ 15 N values can be used in a statistical analysis carried out in order to link Ecstasy tablets prepared with the same precursors and synthetic pathway. The similarity index obtained after principal component analysis and hierarchical cluster analysis appears to be an efficient way to group tablets seized in different places

δ(15) N from soil to wine in bulk samples and proline.

Science.gov (United States)

Paolini, Mauro; Ziller, Luca; Bertoldi, Daniela; Bontempo, Luana; Larcher, Roberto; Nicolini, Giorgio; Camin, Federica

2016-09-01

The feasibility of using δ(15) N as an additional isotopic marker able to link wine to its area of origin was investigated. The whole production chain (soil-leaves-grape-wine) was considered. Moreover, the research included evaluation of the effect of the fermentation process, the use of different types of yeast and white and red vinification, the addition of nitrogen adjuvants and ultrasound lysis simulating wine ageing. The δ(15) N of grapes and wine was measured in bulk samples and compounds, specifically in proline, for the first time. Despite isotopic fractionation from soil to wine, the δ(15) N values of leaves, grapes, wine and particularly must and wine proline conserved the variability of δ(15) N in the growing soil. Fermentation and ultrasound treatment did not affect the δ(15) N values of grape must, which was therefore conserved in wine. The addition of inorganic or organic adjuvants was able to influence the δ(15) N of bulk wine, depending on the amount and the difference between the δ(15) N of must and that of the adjuvant. The δ(15) N of wine proline was not influenced by adjuvant addition and is therefore the best marker for tracing the geographical origin of wine. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

δ 15N Studies of Nitrogen Use by the Red Mangrove, Rhizophora mangle L. in South Florida

Science.gov (United States)

Fry, B.; Bern, A. L.; Ross, M. S.; Meeder, J. F.

2000-02-01

To help define nitrogen (N) sources and patterns of N processing in mangrove ecosystems, mangrove leaf nitrogen contents and δ 15N values were assayed in three marshes along the south Florida coast. In each marsh, leaf samples were collected from dwarf mangroves at interior locations and taller mangroves at the ocean fringe. Leaf % N and δ 15N values did not differ consistently between dwarf and tall mangroves, even though there were large variations in δ 15N (18‰ range, -5 to +13‰) and % N (1·2% range, 0·9-2·1%). Highest % N and δ 15N values occurred along the western margin of Biscayne Bay where canals draining agricultural lands deliver high-nitrate waters to fringing mangrove marshes. High mangrove δ 15N values may be good biomonitors of anthropogenic N loading to south Florida estuaries. Lower values likely reflect less anthropogenic N entering the mangrove marshes, as well as differences in plant physiology that occur along the fringe-dwarf gradient.

An empirical evaluation of Value-at-Risk: The case of the Belgrade Stock Exchange index - BELEX15

Directory of Open Access Journals (Sweden)

Đaković Vladimir

2012-03-01

Full Text Available The subject of the research is to test and analyze VaR (Value-at-Risk methods of market risk management on the financial market of the Republic of Serbia. Thus, concrete research is conducted in the period 2005 - 2011, with the goal of VaR methods performance assessment on the Serbian financial market. The tested VaR methods are Historical simulation (HS and Delta normal VaR with 95% and 99% confidence level for 50, 100, 200 and 250 days. BELEX15 stock index of the Belgrade Stock Exchange, which comprises of 15 most liquid securities of the Serbian financial market, is used as a benchmark indicator of the conditions on the Serbian financial market. The goals which are intended for achieving in the research are focused to Historical simulation (HS and Delta normal VaR performance assessment on, according to many criteria, 'specific'-transitory financial market of the Republic of Serbia. The basic goal of the research is to come to concrete, practically tested, knowledge about the possibility and performance of VaR methods application on the financial market of the Republic of Serbia in function of investment decisions optimizing. Research results point to the necessity of VaR methods application in market risk management on the financial market of the Republic of Serbia.

Delta progradation and Neoglaciation, Laguna Parón, Cordillera Blanca, Peru

Science.gov (United States)

Seltzer, Geoffrey O.; Rodbell, Donald T.

2005-10-01

The history of Holocene glaciation serves as an important record of glacier mass balance and, therefore, of climatic change. The moraine record of Holocene glaciation in the tropical Andes, however, is fragmentary and poorly dated. In contrast, increases in the rate of accumulation of inorganic sediment in glacier-fed lakes have been linked to periods of Neoglaciation in many mountain regions. The interpretation of such a record of Neoglaciation from sediment cores in glacier-fed lakes in the tropical Andes can provide the continuity and chronologic control that is lacking in the existing moraine record. Unusual exposures of glacial lacustrine sediment in the Cordillera Blanca, Peru, provide a rare opportunity to assess the link between climatic change, glaciation, and lacustrine sedimentation.Intentional lowering of water levels in Laguna Parón (9°S, 77°44 W, 4200 m a.s.l.) in 1985 resulted in the incision and exposure of at least 20 m of deltaic deposits at the eastern end of the lake. Three deltaic units can be identified: horizontal topset beds, steeply dipping and deformed foreset beds, and horizontally laminated fine-grained sediment. Six radiocarbon ages ranging from 1800 +/- 210 to 465 +/- 95 14C yr BP on wood indicate that the average rate of delta progradation in the late Holocene has been approximately 290 m per 1000 yr. The lake formed during deglaciation at least 10 000 yr ago and if such a rate of progradation of the delta had prevailed over the entire Holocene, then the delta would be at least three times as extensive as it is today. Thus the rate of delta progradation has varied significantly over the Holocene. We suggest that the rate of delta progradation was at least three times greater when glaciers were in advanced positions. These positions are clearly delimited by Neoglacial moraines, which are within 1-2 km of the exposures studied and within 1 km of modern ice limits. The most recent increase in the rate of delta progradation is

Reconstruction of fire history of the Yukon-Kuskokwim Delta, Alaska

Science.gov (United States)

Sae-lim, J.; Mann, P. J.; Russell, J. M.; Natali, S.; Vachula, R. S.; Schade, J. D.; Holmes, R. M.

2017-12-01

Wildfire is an important disturbance in Arctic ecosystems and can cause abrupt perturbations in global carbon cycling and atmospheric chemistry. Over the next few decades, arctic fire frequency, intensity and extent is projected to increase due to anthropogenic climate change, as regional air temperatures are increasing at more than twice the global average. In order to more accurately predict the anthropogenic impacts of climate change on tundra fire regimes, it is critical to have detailed knowledge of the natural frequency and extent of past wildfires. However, reliable historical records only extend back a few hundred years, whereas climatic shifts have affected fire regimes for thousands of years. In this work we analyzed a lake sediment core collected from the Yukon-Kuskokwim (YK) Delta, Alaska, a region that has recently experienced fire and is predicted to see increasing fire frequency in the near future. Our primary lake site is situated adjacent to recent burned areas, providing a `calibration' point and also attesting to the sensitivity of the sites. We used charcoal counts alongside geochemical measurements (C:N, 13C, 15N, 210Pb, X-ray fluorescence analyses of elemental chemistry) to reconstruct past fire history and ecosystem responses during the late Holocene. Average C (%C) and N concentrations (%N) in the core were 8.10 ±0.74% and 0.48 ±0.05%, resulting in C:N ratios of 16.80 ±0.74. The values are generally stable, with no obvious trend in C, N or C:N with depth; however, fluctuations in sediment composition in other nearby lake sediment cores possibly suggests shifts in lake conditions (oxic, anoxic) over time that might result from paleofires. This study provides a baseline for estimated fire return intervals in the YK Delta that will support more accurate projections of tundra fire frequencies under a changing climate.

Measurement of event-by-event transverse momentum and multiplicity fluctuations using strongly intensive measures $\\Delta[P_T, N]$ and $\\Sigma[P_T, N]$ in nucleus-nucleus collisions at the CERN Super Proton Synchrotron

CERN Document Server

Anticic, T.; Bartke, J.; Beck, H.; Betev, L.; Białkowska, H.; Blume, C.; Boimska, B.; Book, J.; Botje, M.; Bunčić, P.; Christakoglou, P.; Chung, P.; Chvala, O.; Cramer, J.; Eckardt, V.; Fodor, Z.; Foka, P.; Friese, V.; Gaździcki, M.; Grebieszkow, K.; Höhne, C.; Kadija, K.; Karev, A.; Kolesnikov, V.; Kowalski, M.; Kresan, D.; Laszlo, A.; Lacey, R.; van Leeuwen, M.; Maćkowiak-Pawłowska, M.; Makariev, M.; Malakhov, A.; Melkumov, G.; Mitrovski, M.; Mrówczyński, S.; Pálla, G.; Panagiotou, A.; Pluta, J.; Prindle, D.; Pühlhofer, F.; Renfordt, R.; Roland, C.; Roland, G.; Rybczyński, M.; Rybicki, A.; Sandoval, A.; Rustamov, A.; Schmitz, N.; Schuster, T.; Seyboth, P.; Siklér, F.; Skrzypczak, E.; Słodkowski, M.; Stefanek, G.; Stock, R.; Ströbele, H.; Susa, T.; Szuba, M.; Varga, D.; Vassiliou, M.; Veres, G.; Vesztergombi, G.; Vranić, D.; Włodarczyk, Z.; Wojtaszek-Szwarc, A.

2015-10-12

Results from the NA49 experiment at the CERN SPS are presented on event-by-event transverse momentum and multiplicity fluctuations of charged particles, produced at forward rapidities in central Pb+Pb interactions at beam momenta 20$A$, 30$A$, 40$A$, 80$A$, and 158$A$ GeV/c, as well as in systems of different size ($p+p$, C+C, Si+Si, and Pb+Pb) at 158$A$ GeV/c. This publication extends the previous NA49 measurements of the strongly intensive measure $\\Phi_{p_T}$ by a study of the recently proposed strongly intensive measures of fluctuations $\\Delta[P_T, N]$ and $\\Sigma[P_T, N]$. In the explored kinematic region transverse momentum and multiplicity fluctuations show no significant energy dependence in the SPS energy range. However, a remarkable system size dependence is observed for both $\\Delta[P_T, N]$ and $\\Sigma[P_T, N]$, with the largest values measured in peripheral Pb+Pb interactions. The results are compared with NA61/SHINE measurements in $p+p$ collisions, as well as with predictions of the UrQMD and ...

A simple method for measuring signs of {sup 1}H{sup N} chemical shift differences between ground and excited protein states

Energy Technology Data Exchange (ETDEWEB)

Bouvignies, Guillaume; Korzhnev, Dmitry M.; Neudecker, Philipp; Hansen, D. Flemming [University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry (Canada); Cordes, Matthew H. J. [University of Arizona, Department of Chemistry and Biochemistry (United States); Kay, Lewis E., E-mail: kay@pound.med.utoronto.c [University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry (Canada)

2010-06-15

NMR relaxation dispersion spectroscopy is a powerful method for studying protein conformational dynamics whereby visible, ground and invisible, excited conformers interconvert on the millisecond time-scale. In addition to providing kinetics and thermodynamics parameters of the exchange process, the CPMG dispersion experiment also allows extraction of the absolute values of the chemical shift differences between interconverting states, |{Delta}{omega}-tilde|, opening the way for structure determination of excited state conformers. Central to the goal of structural analysis is the availability of the chemical shifts of the excited state that can only be obtained once the signs of {Delta}{omega}-tilde are known. Herein we describe a very simple method for determining the signs of {sup 1}H{sup N} {Delta}{omega}-tilde values based on a comparison of peak positions in the directly detected dimensions of a pair of {sup 1}H{sup N}-{sup 15}N correlation maps recorded at different static magnetic fields. The utility of the approach is demonstrated for three proteins that undergo millisecond time-scale conformational rearrangements. Although the method provides fewer signs than previously published techniques it does have a number of strengths: (1) Data sets needed for analysis are typically available from other experiments, such as those required for measuring signs of {sup 15}N {Delta}{omega}-tilde values, thus requiring no additional experimental time, (2) acquisition times in the critical detection dimension can be as long as necessary and (3) the signs obtained can be used to cross-validate those from other approaches.

Isotopic variations in the nitrogen of natural humic and bituminous organic substances

International Nuclear Information System (INIS)

Stiehl, G.; Lehmann, M.

1980-01-01

delta 15 N-values and nitrogen contents of a series of humic and bituminous organic sediments of different ranks were determined. The change of the isotopic abundance of nitrogen was investigated during heating in model experiments, using a gas flame coal. In the case of humic carbon coals the relative nitrogen contents vary from 0.8 to 1.4% and the delta 15 N-values from + 3.5 to + 6.3 parts per thousand increasing from the brown coal to anthracite ranks. During the coalification process both the delta 15 N-values and the relative nitrogen contents do not vary continuously with the rank, but pass through maxima and minima. Model experiments using a gas flame coal show the same trend. Nitrogen with delta 15 N-values of + 2.8 or -7 parts per thousand was released in pyrolysis experiments, applying a gas flame coal and a steam coal at temperatures of 650 and 1000 0 C, respectively. The investigated bituminous sediments yielded relative amounts of 0.1 to 0.8% with delta 15 N-values of + 4.2 to + 10.7 parts per thousand. The obtained results are discussed with respect to the elucidation of nitrogen genesis in natural gas deposits. (author)

15N fractionation in infrared-dark cloud cores

Science.gov (United States)

Zeng, S.; Jiménez-Serra, I.; Cosentino, G.; Viti, S.; Barnes, A. T.; Henshaw, J. D.; Caselli, P.; Fontani, F.; Hily-Blant, P.

2017-07-01

Context. Nitrogen is one of the most abundant elements in the Universe and its 14N/15N isotopic ratio has the potential to provide information about the initial environment in which our Sun formed. Recent findings suggest that the solar system may have formed in a massive cluster since the presence of short-lived radioisotopes in meteorites can only be explained by the influence of a supernova. Aims: We seek to determine the 14N/15N ratio towards a sample of cold and dense cores at the initial stages in their evolution. Methods: We observed the J = 1 → 0 transitions of HCN, H13CN, HC15N, HN13C, and H15NC towards a sample of 22 cores in four infrared-dark clouds (IRDCs) which are believed to be the precursors of high-mass stars and star clusters. Assuming LTE and a temperature of 15 K, the column densities of HCN, H13CN, HC15N, HN13C, and H15NC are calculated and their 14N/15N ratio is determined for each core. Results: The 14N/15N ratios measured in our sample of IRDC cores range between 70 and ≥763 in HCN and between 161 and 541 in HNC. These ratios are consistent with the terrestrial atmosphere (TA) and protosolar nebula (PSN) values, and with the ratios measured in low-mass prestellar cores. However, the 14N/15N ratios measured in cores C1, C3, F1, F2, and G2 do not agree with the results from similar studies towards the same cores using nitrogen bearing molecules with nitrile functional group (-CN) and nitrogen hydrides (-NH) although the ratio spread covers a similar range. Conclusions: Relatively low 14N/15N ratios amongst the four-IRDCs were measured in IRDC G which are comparable to those measured in small cosmomaterials and protoplanetary disks. The low average gas density of this cloud suggests that the gas density, rather than the gas temperature, may be the dominant parameter influencing the initial nitrogen isotopic composition in young PSN. The reduced spectra (FITS files) are only available at the CDS via anonymous ftp to http

Sensitivity improvement for correlations involving arginine side-chain N{epsilon}/H{epsilon} resonances in multi-dimensional NMR experiments using broadband {sup 15}N 180{sup o} pulses

Energy Technology Data Exchange (ETDEWEB)

Iwahara, Junji; Clore, G. Marius [National Institutes of Health, Laboratory of Chemical Physics, Building 5, National Institute of Diabetes and Digestive and Kidney Disease (United States)], E-mail: mariusc@intra.niddk.nih.gov

2006-12-15

Due to practical limitations in available {sup 15}N rf field strength, imperfections in {sup 15}N 180{sup o} pulses arising from off-resonance effects can result in significant sensitivity loss, even if the chemical shift offset is relatively small. Indeed, in multi-dimensional NMR experiments optimized for protein backbone amide groups, cross-peaks arising from the Arg guanidino {sup 15}N{epsilon} ({approx}85 ppm) are highly attenuated by the presence of multiple INEPT transfer steps. To improve the sensitivity for correlations involving Arg N{epsilon}-H{epsilon} groups, we have incorporated {sup 15}N broadband 180 deg. pulses into 3D {sup 15}N-separated NOE-HSQC and HNCACB experiments. Two {sup 15}N-WURST pulses incorporated at the INEPT transfer steps of the 3D {sup 15}N-separated NOE-HSQC pulse sequence resulted in a {approx}1.5-fold increase in sensitivity for the Arg N{epsilon}-H{epsilon} signals at 800 MHz. For the 3D HNCACB experiment, five {sup 15}N Abramovich-Vega pulses were incorporated for broadband inversion and refocusing, and the sensitivity of Arg{sup 1}H{epsilon}-{sup 15}N{epsilon}-{sup 13}C{gamma}/{sup 13}C{delta} correlation peaks was enhanced by a factor of {approx}1.7 at 500 MHz. These experiments eliminate the necessity for additional experiments to assign Arg {sup 1}H{epsilon} and {sup 15}N{epsilon} resonances. In addition, the increased sensitivity afforded for the detection of NOE cross-peaks involving correlations with the {sup 15}N{epsilon}/{sup 1}H{epsilon} of Arg in 3D {sup 15}N-separated NOE experiments should prove to be very useful for structural analysis of interactions involving Arg side-chains.

Estimation of the endogenous N proportions in ileal digesta and faeces in 15N-labelled pigs

International Nuclear Information System (INIS)

Simon, O.; Bergner, H.

1987-01-01

4 castrated male pigs 40 kg fitted with simple 'T' cannulas in the terminal ileum were given 15 N-labelled ammonium salts, added to a low protein diet, for 6 days. Excretion of 15 N in urine and feces was monitored daily throughout the labelling and subsequent experimental periods. During the experimental period the pigs were given a diet based on wheat and fish meal, supplemented with varying levels of partially hydrolyzed straw meal to give crude fiber contents ranging from 40 to 132 g/kg. After adaptation to the particular levels of straw meal, feces and ileal digesta were collected during successive 24 h periods. N digestibility values were determined by the chromium oxide ratio method. The retention of 15 N-labelled non-specific N was 0.46 of the dose given. The validity of using urine values as a measure of 15 N abundance in endogenous N was demonstrated by the similarity of 15 N abundance in urine immediately before slaughter at the end of the experiment and in the digestive secretory organs thereafter. The average amount of endogenous N passing the terminal ileum was 3.4 g/day or 0.30-0.50 of total ileal N flow. This was not affected by dietary fiber level. The proportion of fecal N which was of endogenous origin was similar to that in ileal digesta, suggesting similar utilization of endogenous and residual dietary N by hindgut bacteria. Half the endogenous N entering the large intestine was reabsorbed there. Increasing dietary crude fiber from 40 to 132 g/kg increased fecal endogenous N excretion from 1.3 to 2.0 g/animal and day. (author)

High Frequency Monitoring of Isotopic Signatures Elucidates Potential Effects of Restoring Floodplain Habitat in the Sacramento-San Joaquin Delta, California, USA

Science.gov (United States)

Nakamoto, B. J.; Fogel, M. L.; Jeffres, C.; Viers, J. H.

2017-12-01

Increasing the quality and quantity of habitat for native species in the Sacramento-San Joaquin Delta is a high priority for California water managers. The McCormack-Williamson Tract (MWT) is a subsided island (38.253° N -121.284° W) situated at the confluence of the Cosumnes and Mokelumne rivers, near the inland extent of tidal influence. MWT experienced unexpected levee failure on February 11, 2017, during the wettest year of record for the Mokelumne-Cosumnes river system, which provided a unique opportunity to examine the potential trajectory of future restoration actions within the Delta. We carried out high frequency sampling (n=32, 13% of days) of suspended particulate organic matter (SPOM) and waters in the Mokelumne and Cosumnes river systems, including nearby sloughs, and the post-failure, flooded interior of MWT. Carbon (δ13C) and nitrogen (δ15N) isotopes in SPOM and δ2H and δ18O of waters were analyzed and in situ water quality data were collected in tandem, thus contextualizing isotopic data. Sampling was confined to an 8 km2 region surrounding MWT (6.7 km2 interior). This unintentional flooding provided a natural before-after-control-impact experiment to study the effect that sudden inundation of a Delta island can have on food web development and ecosystem function. Source waters were isotopically distinct (p0.9), providing a semi-conservative tracer of mixing. The δ13C values of SPOM varied between -37.3 and -23.9‰ and were significantly more negative on the flooded island by 1.2‰ (porganic carbon concomitant with accelerated ecosystem metabolism. Concurrently, δ15N values varied between 1.0 and 12.4‰ and were not significantly different between riverine and flooded island sites. Our data indicate that this river system is highly dynamic over short periods of flood inundation (13 weeks) with new freshwater habitats exhibiting higher productivity than their riverine counterparts and could therefore increase autochthonous subsidies to

Identifying N fertilizer regime and vegetable production system in tropical Brazil using (15) N natural abundance.

Science.gov (United States)

Inácio, Caio T; Urquiaga, Segundo; Chalk, Phillip M; Mata, Maria Gabriela F; Souza, Paulo O

2015-12-01

This study was conducted in areas of vegetable production in tropical Brazil, with the objectives of (i) measuring the variation in δ(15)  N in soils, organic N fertilizer sources and lettuce (Lactuca sativa L.) from different farming systems, (ii) measuring whether plant δ(15)  N can differentiate organic versus conventional lettuce and (iii) identifying the factors affecting lettuce δ(15)  N. Samples of soil, lettuce and organic inputs were taken from two organic, one conventional and one hydroponic farm. The two organic farms had different N-sources with δ(15)  N values ranging from 0.0 to +14.9‰ (e.g. leguminous green manure and animal manure compost, respectively), and differed significantly (P hydroponic lettuce δ(15)  N (+4.5 ± 0.2‰) due to manure inputs. The N from leguminous green manure made a small contribution to the N nutrition of lettuce in the multi-N-source organic farm. To differentiate organic versus conventional farms using δ(15)  N the several subsets of mode of fertilization should be considered. Comparisons of δ(15)  N of soil, organic inputs and lettuce allowed a qualitative analysis of the relative importance of different N inputs. © 2015 Society of Chemical Industry.

[Accumulation responses of seeds and seedlings to 15N isotope for two typical broadleaved trees in Northeast China.

Science.gov (United States)

Wang, Guang Chen; Song, Yuan; Yan, Qiao Ling; Zhang, Jin Xin

2016-08-01

Two typical broadleaved trees (i.e., Fraxinus rhynchophylla and Acer mono) with wind-dispersed seeds in Northeast China were selected in this study. A method of 15 N isotope labeling was used to explore the accumulation responses of seeds and seedlings to 15 N-urea soaking concentration (0, 0.05, 0.1 and 0.2 g·L -1 ), soaking time (4, 8 and 12 days) and leaf stage (2, 4, 6, and 8 leaves). The results showed that 15 N-urea soaking concentration and soaking time had significantly positive effects on δ 15 N values of seeds, i.e., higher 15 N-urea concentration and longer period of soaking (0.2 g·L -1 +12 d) were contributed to more 15 N accumulation of seeds. The maximum multiples of 15 N accumulation in F. rhynchophylla seeds and A. mono seeds were observed in 0.1 g·L -1 + (4 d, 8 d) and 0.05 g·L -1 + (4 d, 8 d), respectively. The loss rate of δ 15 N values decreased markedly from 2 leaves to 6 leaves and then kept relatively stable with the increasing seedling height, and the total δ 15 N values of seedlings started to decline at the stage of 8 leaves. These results suggested that seedlings with 6 leaves were more suitable for tracking seedling source. The δ 15 N values in leaves of seedlings were significantly positively correlated with 15 N-urea concentration level, soaking time and δ 15 N values of seeds. Overall, the accumulation of 15 N-urea could be found in seeds and seedlings of F. rhynchophylla and A. mono. The combination of 15 N-urea concentration (0.1 g·L -1 ), soaking time (8 d) and leaf stage (6 leaves) was the most suitable for tracking the seeds and seedlings of these two broadleaved trees.

δ15N of seagrass leaves for monitoring anthropogenic nutrient increases in coral reef ecosystems

International Nuclear Information System (INIS)

Yamamuro, M.; Kayanne, H.; Yamano, H.

2003-01-01

In a coral reef environment, a slight increase in dissolved inorganic nitrogen (DIN;≥1.0 μM) can alter the ecosystem via macroalgal blooms. We collected seagrass leaves from the tropical and subtropical Pacific Ocean in five countries and examined the interactions between nutrient concentrations (C, N, P), molar ratios of nutrients, and δ 15 N to find a possible indicator of the DIN conditions. Within most sites, the concentrations of nutrients and their molar ratios showed large variations owing to species-specific values. On the other hand, almost identical δ 15 N values were found in seagrass leaves of several species at each site. The correlations between δ 15 N and nutrient concentrations and between δ 15 N and molar ratios of nutrients suggested that nutrient availability did not affect the δ 15 N value of seagrass leaves by altering the physiological condition of the plants. Increases in δ 15 N of seagrass leaves mostly matched increases in DIN concentrations in the bottom water. We suggest that δ 15 N in seagrass leaves can be a good tool to monitor time-integrated decrease/increase of DIN concentrations at a site, both in the water column and the interstitial water

Entropy and optimality in river deltas

Science.gov (United States)

Tejedor, Alejandro; Longjas, Anthony; Edmonds, Douglas A.; Zaliapin, Ilya; Georgiou, Tryphon T.; Rinaldo, Andrea; Foufoula-Georgiou, Efi

2017-10-01

The form and function of river deltas is intricately linked to the evolving structure of their channel networks, which controls how effectively deltas are nourished with sediments and nutrients. Understanding the coevolution of deltaic channels and their flux organization is crucial for guiding maintenance strategies of these highly stressed systems from a range of anthropogenic activities. To date, however, a unified theory explaining how deltas self-organize to distribute water and sediment up to the shoreline remains elusive. Here, we provide evidence for an optimality principle underlying the self-organized partition of fluxes in delta channel networks. By introducing a suitable nonlocal entropy rate (nER) and by analyzing field and simulated deltas, we suggest that delta networks achieve configurations that maximize the diversity of water and sediment flux delivery to the shoreline. We thus suggest that prograding deltas attain dynamically accessible optima of flux distributions on their channel network topologies, thus effectively decoupling evolutionary time scales of geomorphology and hydrology. When interpreted in terms of delta resilience, high nER configurations reflect an increased ability to withstand perturbations. However, the distributive mechanism responsible for both diversifying flux delivery to the shoreline and dampening possible perturbations might lead to catastrophic events when those perturbations exceed certain intensity thresholds.

HECTR [Hydrogen Event Containment Transient Response] Version 1.5N: A modification of HECTR Version 1.5 for application to N Reactor

International Nuclear Information System (INIS)

Camp, A.L.; Dingman, S.E.

1987-05-01

This report describes HECTR Version 1.5N, which is a special version of HECTR developed specifically for application to the N Reactor. HECTR is a fast-running, lumped-parameter containment analysis computer program that is most useful for performing parametric studies. The main purpose of HECTR is to analyze nuclear reactor accidents involving the transport and combustion of hydrogen, but HECTR can also function as an experiment analysis tool and can solve a limited set of other types of containment problems. Version 1.5N is a modification of Version 1.5 and includes changes to the spray actuation logic, and models for steam vents, vacuum breakers, and building cross-vents. Thus, all of the key features of the N Reactor confinement can be modeled. HECTR is designed for flexibility and provides for user control of many important parameters, if built-in correlations and default values are not desired

Nitrogen cycling in an extreme hyperarid environment inferred from δ15N analyses of plants, soils and herbivore diet

Science.gov (United States)

Díaz, Francisca P.; Frugone, Matías; Gutiérrez, Rodrigo A.; Latorre, Claudio

2016-03-01

Climate controls on the nitrogen cycle are suggested by the negative correlation between precipitation and δ15N values across different ecosystems. For arid ecosystems this is unclear, as water limitation among other factors can confound this relationship. We measured herbivore feces, foliar and soil δ15N and δ13C values and chemically characterized soils (pH and elemental composition) along an elevational/climatic gradient in the Atacama Desert, northern Chile. Although very positive δ15N values span the entire gradient, soil δ15N values show a positive correlation with aridity as expected. In contrast, foliar δ15N values and herbivore feces show a hump-shaped relationship with elevation, suggesting that plants are using a different N source, possibly of biotic origin. Thus at the extreme limits of plant life, biotic interactions may be just as important as abiotic processes, such as climate in explaining ecosystem δ15N values.

Nitrogen cycling in an extreme hyperarid environment inferred from δ(15)N analyses of plants, soils and herbivore diet.

Science.gov (United States)

Díaz, Francisca P; Frugone, Matías; Gutiérrez, Rodrigo A; Latorre, Claudio

2016-03-09

Climate controls on the nitrogen cycle are suggested by the negative correlation between precipitation and δ(15)N values across different ecosystems. For arid ecosystems this is unclear, as water limitation among other factors can confound this relationship. We measured herbivore feces, foliar and soil δ(15)N and δ(13)C values and chemically characterized soils (pH and elemental composition) along an elevational/climatic gradient in the Atacama Desert, northern Chile. Although very positive δ(15)N values span the entire gradient, soil δ(15)N values show a positive correlation with aridity as expected. In contrast, foliar δ(15)N values and herbivore feces show a hump-shaped relationship with elevation, suggesting that plants are using a different N source, possibly of biotic origin. Thus at the extreme limits of plant life, biotic interactions may be just as important as abiotic processes, such as climate in explaining ecosystem δ(15)N values.

Inhabiting the Delta: A Landscape Approach to Transformative Socio-Ecological Restoration

Directory of Open Access Journals (Sweden)

Brett Milligan

2017-09-01

Full Text Available doi: https://doi.org/10.15447/sfews.2017v15iss3art3Current legislation and plans for the Sacramento–San Joaquin Delta (Delta call for large-scale restoration of aquatic and terrestrial habitats, which will require significant changes in waterways, land uses, and cultural patterns. These re-made landscapes will be subject to a variety of new human uses, which Delta planning and adaptive management literature has yet to adequately consider. Failing to account for human uses and evolving place values can lead to diminished performance and public support for Delta restoration efforts. Our empirical study examined restored and naturalized Delta landscapes using an integrative landscape approach that seeks to reconcile multiple goals and land-use agendas that span ecological, social, economic, and political domains. The research design consisted of six overlapping methods that included a planning, policy, and law review specific to the Delta; surveys and interviews with approximately 100 land managers, scientists, land-owners, law-enforcement personnel, agency representatives, and Delta residents; nine case studies of restored and naturalized delta landscapes; GIS mapping; and extensive field work. Findings derived from the synthesis of these methods show that human uses of the Delta’s re-wilded landscapes are diverse and pervasive. Given the infrastructural and urbanized context of the region, these environments are subject to multiple and sometimes conflicting uses, perceptions, and place values. Though these myriad uses cannot be fully predicted or controlled (nor should they be, findings showed that more proactive and inclusive planning for human uses can encourage or discourage particular uses while also building constituency, support, and active engagement in ecological restoration efforts. We conclude that reconciling human uses with ecological recovery in the Delta will require a more localized, multi-functional, and creative approach to

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

Science.gov (United States)

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

2009-01-01

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

Tracer experiments with 15N-labelled wheat to determine the endogenous and exogenous fecal N-proportion

International Nuclear Information System (INIS)

Krawielitzki, K.; Timm, E.

1978-01-01

In an experiment with growing Wistar rats of 100 g live weight the N-values and the 15 N-frequency of the nitrogen in feces, urine and the experimental carcasses were determined after feeding 15 N-labelled wheat. Proceeding from Czarnetzki's multicompartment model (1969) for N-metabolism in monogastric animals, the measured data were used to calculate the endogenous and exogenous fecal N-proportion of total nitrogen. In agreement with earlier studies the intestinal nitrogen loss was found to rise as the protein intake increased. In this experiment, the intestinal nitrogen loss went up from 8.2 mg N/animal and day (N-free diet) to 33.9 mg N/animal and day at a daily nitrogen intake of 240 mg/animal and day. The true digestibility of the wheat protein (determined by taking into account the rise of fecal N loss) was 97.2% this value being 8.4 units higher than the true digestibility calculated by the conventional regressive method of fecal analysis with a constant value being taken for fecal N loss. In connection with earlier findings, this experiment allows to draw the conclusion that the true digestibility determined conventionally by regression analysis does not reflect the actual digestibility of the protein. (author)

Using nitrogen stable isotope ratios ({delta}{sup 15}N) of macroalgae to determine the effectiveness of sewage upgrades: changes in the extent of sewage plumes over four years in Moreton Bay, Australia

Energy Technology Data Exchange (ETDEWEB)

Costanzo, Simon D. [National Research Centre for Environmental Toxicology, University of Queensland, 39 Kessels Road, Coopers Plains, QLD 4108 (Australia)]. E-mail: s.costanzo@uq.edu.au; Udy, James [Marine Botany, Centre for Marine Studies, University of Queensland, 4072 (Australia); Longstaff, Ben [Environmental Protection Agency, 80 Meiers Road, Indooroopilly, QLD 4058 (Australia); Jones, Adrian [University of Maryland Center for Environmental Science, P.O. Box 775, Cambridge, MD 21613, USA (United States)

2005-07-01

Nitrogen loading to aquatic ecosystems from sewage is recognised worldwide as a growing problem. The use of nitrogen stable isotopes as a means of discerning sewage nitrogen in the environment has been used annually by the Ecosystem Health Monitoring Program in Moreton Bay (Australia) since 1997 when the technique was first developed. This ('sewage plume mapping') technique, which measures the {delta}{sup 15}N isotopic signature of the red macroalga Catenella nipae after incubation in situ, has demonstrated a large reduction in the magnitude and spatial extent of sewage nitrogen within Moreton Bay over the past 5 years. This observed reduction coincides with considerable upgrades to the nitrogen removal efficacy at several sewage treatment plants within the region. This paper describes the observed changes and evaluates whether they can be attributed to the treatment upgrades.

/sup 15/N analysis in nutritional and metabolic research of infancy

Energy Technology Data Exchange (ETDEWEB)

Heine, W; Richter, I; Plath, C; Wutzke, K; Drescher, U [Rostock Univ. (German Democratic Republic). Bereich Medizin

1982-01-01

Investigation of protein metabolism in nutritional pediatric research by means of /sup 15/N tracer techniques has been relatively seldom used up to now. /sup 15/N-labelled compounds for these purposes are not injurious to health. The technique is based on oral or intravenous application of the tracer substances and on /sup 15/N analysis of the urine fractions. The subsequent calculation of protein synthesis and breakdown rate, turnover, and the reutilisation of amino acids from protein breakdown as well as the size of the metabolic pool offers detailed information of protein metabolism. Determination of these parameters were performed in infants on breast milk, formula feeding and on chemically defined diet. As an example of utilisation of D-amino acids for protein synthesis the /sup 15/N-D-phenylalanine retention of parenteral nutrition was found to be 33% of the applied doses at an average. An oral /sup 15/N-glycine loading test proved to be of value for the prediction of the therapeutic effect of human growth hormone. /sup 15/N tracer technique was also tested in utilizing /sup 15/N-urea for bacterial protein synthesis of the intestinal flora and by incorporation of /sup 15/N from /sup 15/N-glycine and /sup 15/N-lysine into the jejunal mucosa for measuring the enterocyte regeneration.

Synthesis and NMR characterization of ( sup 15 N)taurine (2-( sup 15 N)aminoethanesulfonic acid)

Energy Technology Data Exchange (ETDEWEB)

Philippossian, G.; Welti, D.H.; Fumeaux, R.; Richli, U.; Anantharaman, K. (Nestle Research Centre, Nestec Ltd., Lausanne (Switzerland))

1989-11-01

The title compound was prepared in three steps with 55% overall yield starting from potassium ({sup 15}N)phthalimide. The synthetic route involved reaction with 1,2-dibromoethane, hydrolysis of the resulting N-(2-bromoethyl) ({sup 15}N)phthalimide with HBr and treatment of the 2-bromoethyl({sup 15}N)amine thus formed with sodium sulphite. The product was characterized by {sup 13}C, {sup 1}H and {sup 15}N NMR spectroscopy. The absolute coupling constants of {sup 15}N with the {sup 13}C nuclei and the non-exchanging protons were determined and an unambiguous assignment of the proton signals obtained. (author).

Variations of the natural isotopic composition (15N) of mineral nitrogen from calcareous soils, studied during incubation experiment and on the field

International Nuclear Information System (INIS)

Mariotti, A.; Guillemot, J.

1980-01-01

This study was intended to follow the variations of isotope composition of mineral nitrogen formed during incubation of calcareous soils (rendzine), humidity and temperature conditions approximating natural ones. We compared the isotope composition with that of mineral nitrogen formed in a lysimeter cut out from a natural soil with the same pedological features. During the incubation experiments, two steps were recognized. A step with production of nitrates and nitrites depleted in 15 N and a second step where the isotope composition leans towards an equilibrium value. During the first step, the 15 N depletion for the sum NO 3 + NO 2 correlates with a 15 N enrichment for ammonium. On the whole, the total mineral nitrogen isotope composition is approximately constant. This first step corresponds also to a great speed of nitrification, to the presence of nitrite and to a large evolution (production or use) of ammonium. On the contrary, nitrites have disappeared and ammonium is in dynamic equilibrium (constant concentration) when the delta 15 N of nitrates is stabilized. In another set of experiments, with the same conditions, small quantity of a nitrogen substrate (vegetal proteins or amino acids) easily mineralizable, was added to the soil: the 15 N depletion of NO 3 + NO 2 formed during the first step is much greater than with the mere soil. It is concluded that the initial step corresponds to the fast mineralization of a very labile organic component which could be, for the mere soil, the microbial biomass destroyed during air-drying of sample before incubations: this could correspond to the 'flush effect'. On the contrary, the step when nitrates becomes constant could correspond to the mineralization (slower and more regular) of an another organic pool, perhaps part of humified organic matter [fr

15N/14N variations in Cretaceous Atlantic sedimentary sequences: implication for past changes in marine nitrogen biogeochemistry

Science.gov (United States)

Rau, G.H.; Arthur, M.A.; Dean, W.E.

1987-01-01

At two locations in the Atlantic Ocean (DSDP Sites 367 and 530) early to middle Cretaceous organic-carbon-rich beds ("black shales") were found to have significantly lower ??15N values (lower 15N/14N ratios) than adjacent organic-carbon-poor beds (white limestones or green claystones). While these lithologies are of marine origin, the black strata in particular have ??15N values that are significantly lower than those previously found in the marine sediment record and most contemporary marine nitrogen pools. In contrast, black, organic-carbon-rich beds at a third site (DSDP Site 603) contain predominantly terrestrial organic matter and have C- and N-isotopic compositions similar to organic matter of modern terrestrial origin. The recurring 15N depletion in the marine-derived Cretaceous sequences prove that the nitrogen they contain is the end result of an episodic and atypical biogeochemistry. Existing isotopic and other data indicate that the low 15N relative abundance is the consequence of pelagic rather than post-depositional processes. Reduced ocean circulation, increased denitrification, and, hence, reduced euphotic zone nitrate availability may have led to Cretaceous phytoplankton assemblages that were periodically dominated by N2-fixing blue-green algae, a possible source of this sediment 15N-depletion. Lack of parallel isotopic shifts in Cretaceous terrestrially-derived nitrogen (Site 603) argues that the above change in nitrogen cycling during this period did not extend beyond the marine environment. ?? 1987.

Homogeneity of δ15N in needles of Masson pine (Pinus massoniana L.) was altered by air pollution

International Nuclear Information System (INIS)

Kuang Yuanwen; Wen Dazhi; Li Jiong; Sun Fangfang; Hou Enqing; Zhou Guoyi; Zhang Deqiang; Huang Longbin

2010-01-01

The present study investigated the changes of δ 15 N values in the tip, middle and base section (divided by the proportion to needle length) of current- and previous-year needles of Masson pine (Pinus massoniana L.) from two declining forest stands suffering from air pollution, in comparison with one healthy stand. At the healthy stand, δ 15 N in the three sections of both current- and previous-year needles were found evenly distributed, while at the polluted stands, δ 15 N values in the needles were revealed significantly different from the tip to the base sections. The results implied that the distribution of δ 15 N among different parts or sections in foliages was not always homogeneous and could be affected by air pollution. We suggested that the difference of δ 15 N values among pine needle sections should be reconsidered and should not be primarily ignored when the needle δ 15 N values were used to assess plant responses to air pollution. - Values of δ 15 N in needles of Masson pine (Pinus massoniana L.) were uneven and affected by air pollution.

Non-ideal behaviour of imidazolium based room temperature ionic liquids in ethylene glycol at T = (298.15 to 318.15) K

Energy Technology Data Exchange (ETDEWEB)

Singh, Tejwant [Salt and Marine Chemicals Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 002 (India); Kumar, Arvind [Salt and Marine Chemicals Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 002 (India)], E-mail: mailme_arvind@yahoo.com; Kaur, Mandeep; Kaur, Gurpreet; Kumar, H. [Department of Chemistry, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar 144011, Panjab (India)

2009-06-15

Non-ideal behaviour of the room temperature ionic liquids (RTILs), 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF{sub 4}]; 1-octyl-3-methylimidazolium tetrafluoroborate [omim][BF{sub 4}] and 1-butyl-3-methylimidazolium octylsulfate [bmim][C{sub 8}OSO{sub 3}] in ethylene glycol [HOCH{sub 2}CH{sub 2}OH] (EG) have been investigated over the whole composition range at T = (298.15 to 318.15) K. For the purpose, volumetric properties such as excess molar volumes, V{sub m}{sup E}, apparent molar volumes, V{sub {phi}}{sub ,i}, partial molar volumes, V-bar{sub m,i}, excess partial molar volumes, V-bar{sub m,i}{sup E}, and their limiting values at infinite dilution, V{sub {phi}}{sub ,i}{sup {infinity}}, V-bar{sub m,i}{sup {infinity}}, and V-bar{sub m,i}{sup E,{infinity}} respectively have been calculated from the experimental density measurements. The V{sub m}{sup E} results have been analyzed using the Prigogine-Flory-Patterson (PFP) theory. PFP theory has satisfactorily explained the volumetric behaviour of the binary mixtures. Refractive index measurements at 298.15 K have been used to calculate the deviations in refractive indices {delta}{sub {phi}}n and the deviation of molar refraction {delta}{sub x}R from their respective ideal values. Refractive index results have been correlated with volumetric results, and have been interpreted in terms of molecular interactions. Excess properties are fitted to the Redlich-Kister polynomial equation to obtain the binary coefficients and the standard errors.

Physical properties of {anisole + n-alkanes} at temperatures between (293.15 and 303.15) K

International Nuclear Information System (INIS)

Al-Jimaz, Adel S.; Al-Kandary, Jasem A.; Abdul-latif, Abdul-Haq M.; Al-Zanki, Adnan M.

2005-01-01

Density ρ, viscosity η, and refractive index n D , values of {anisole + hexane, or heptane, or octane, or nonane, or decane, or dodecane} binary mixtures over the entire range of mole fraction at temperatures (293.15, 298.15, and 303.15) K, have been investigated at atmospheric pressure. The excess molar volume V E , has been calculated from the experimental measurements. These results were fitted to Redlich and Kister polynomial equation to estimate the binary interaction parameters. The viscosity data were correlated with equations of Grunberg and Nissan, and McAllister. The refractive indices data were used to calculate the specific refractivity R 12 , and also correlated with Lorentz-Lorenz equation. While the excess molar volumes of {anisole + hexane} are negative, and {anisole + heptane} are sigmoidal S-shaped, the remaining binary mixtures are positive. The effects of n-alkanes chain length as well as the temperature on the excess molar volume have been studied. The calculated values have been qualitatively used to explain the intermolecular interaction between the mixing components

Characterization of organic matter in lake sediments from Minnesota and Yellowstone National Park

Science.gov (United States)

Dean, Walter E.

2006-01-01

Samples of sediment from lakes in Minnesota and Yellowstone National Park (YNP) were analyzed for organic carbon (OC), hydrogen richness by Rock-Eval pyrolysis, and stable carbon- and nitrogen-isotope composition of bulk organic matter. Values of delta 13C of lake plankton tend to be around -28 to -32 parts per thousand (0/00). Organic matter with values of delta 13C in the high negative 20s overlap with those of organic matter derived from C3 higher terrestrial plants but are at least 10 0/00 more depleted in 13C than organic matter derived from C4 terrestrial plants. If the organic matter is produced mainly by photosynthetic plankton and is not oxidized in the water column, there may be a negative correlation between H-richness (Rock-Eval pyrolysis H-index) and delta 13C, with more H-rich, algal organic matter having lower values of delta 13C. However, if aquatic organic matter is oxidized in the water column, or if the organic matter is a mixture of terrestrial and aquatic organic matter, then there may be no correlation between H-richness and carbon-isotopic composition. Values of delta 13C lower than about -28 0/00 probably indicate a contribution of bacterial biomass produced in the hypolimnion by chemoautotrophy or methanotrophy. In highly eutrophic lakes in which large amounts of 13C-depleted organic matter is continually removed from the epilimnion by photosynthesis throughout the growing season, the entire carbon reservoir in the epilimnion may become severely 13C-enriched so that 13C-enriched photosynthetic organic matter may overprint 13C-depleted chemosynthetic bacterial organic matter produced in the hypolimnon. Most processes involved with the nitrogen cycle in lakes, such as production of ammonia and nitrate, tend to produce 15N-enriched values of delta 15N. Most Minnesota lake sediments are 15N-enriched. However, some of the more OC-rich sediments have delta 15N values close to zero (delta 15N of air), suggesting that organic matter production is

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

$\\delta N$ formalism from superpotential and holography

CERN Document Server

Garriga, Jaume; Vernizzi, Filippo

2016-02-16

We consider the superpotential formalism to describe the evolution of scalar fields during inflation, generalizing it to include the case with non-canonical kinetic terms. We provide a characterization of the attractor behaviour of the background evolution in terms of first and second slow-roll parameters (which need not be small). We find that the superpotential is useful in justifying the separate universe approximation from the gradient expansion, and also in computing the spectra of primordial perturbations around attractor solutions in the $\\delta N$ formalism. As an application, we consider a class of models where the background trajectories for the inflaton fields are derived from a product separable superpotential. In the perspective of the holographic inflation scenario, such models are dual to a deformed CFT boundary theory, with $D$ mutually uncorrelated deformation operators. We compute the bulk power spectra of primordial adiabatic and entropy cosmological perturbations, and show that the results...

Atmospheric CO2 concentrations and (delta)13C values across the Antarctic Circumpolar Current between New Zealand and Antarctica

International Nuclear Information System (INIS)

Longinelli, Antonio; Selmo, Enricomaria; Giglio, Federico; Langone, Leonardo; Lenaz, Renzo; Ori, Carlo

2007-01-01

Measurements of atmospheric CO 2 concentrations were repeatedly carried out on the vessel 'Italica' of the Italian National Research Program in Antarctica, during cruises from Italy to Antarctica. Discrete air samples were also collected in 4-L Pyrex flasks during these cruises in order to carry out (delta) 13 C analyses on atmospheric CO 2 . The results acquired between New Zealand and Antarctica are reported here. The mean growth rate of the CO 2 concentration from 1996 to 2003 in this area of the Southern Oceans is of about 1.8 ppmv/yr, in good agreement with NOAA/CMDL measurements. The rates of increase from cruise to cruise are rather variable. From 1996-1997 to 1998-1999 cruise the yearly growth rate is 2.75 ppmv/yr, close to the large growth rates measured in several areas and mainly related to the most severe El Nino event of the last years. The other yearly growth rates are of about 1.3 and 2 ppmv for the periods 1998-1999 to 2001-2002 and 2001-2002 to 2003-2004, respectively. The large difference between these two values is probably related to the uncertainty on the only two 2001-2002 discrete measurements of CO 2 concentration in this area. The measured (delta) 13 C values show two completely different distributions and a large interannual variability. The 1998-1999, 2002-2003, and 2003-2004 results obtained between about 55 deg S and 65 deg S across the Antarctic Polar Front show a marked negativization of up to more than 0.2% when compared to the background values. The results are related to local source regions of CO 2 , as frequently found in the Southern Ocean by several authors; the negative (delta) 13 C values are tentatively related to the possible contribution of different causes. Among them, the southward negative gradient of (delta) 13 C of the dissolved inorganic carbon, the contribution from upwelling deep waters and from subsurface processes between the Northern SubAntarctic Front and the Polar Front, and, partly, the contribution of CO 2

Wheat Yield Production Grown on Sandy Soil as Fertilized by Different N-Sources Using 15N-Technique

International Nuclear Information System (INIS)

Ismail, M. M.; Soliman, S. M.; El-Akel, E. A.; El-Sherbieny, A. E.; Awad, E. A. M.

2007-01-01

A pot experiment was carried out to evaluate the ability of some plant residues to meet total N demand of wheat crop in sandy soil and their performance to reduce chemical N fertilizer requirements. Residue-N sources, i.e. soybean and wheat residues were compared to ammonium sulfate as inorganic N source as well as mixtures of residue-N sources and (NH 4 )SO 4 in ratios of (3:1), (1:1) and (1:3), respectively. The nitrogen application rate in all amended pots was kept at 100 mg N pot -1 . The obtained results could be summarized as follows: 1) ry weight of straw and grains of wheat crop was significantly increased this at the addition of nitrogen sources as a result of N-uptake increased. The highest value was observed at the application treatment ratios of (1:1) and (1:3) on the basis of (residue: ammonium sulfate), which can be arranged in this order: Soybean > wheat + soybean > wheat residues. 2) he value of N derived from residues (Ndfr) and fertilizer (Ndff), as well as 15N -recovery ratios can be arranged in this order: Ammonium sulfate > soybean residue > Soybean + wheat residue > wheat residue. 3) he values indicated that 15N -labelled soybean residue in combination with ordinary, ammonium sulfate at the ratios of (*25: 75) and (*50: 50), respectively was found to be effective on 15N -recovery ratios in the straw and grains of wheat crop. 4) he present study indicates that the entire N requirements of wheat crop cannot be met by the separate application of any residue-N source examined.

Correlación y conversión entre los valores de actividad de la colinesterasa plasmática medida por tres técnicas diferentes Correlation and conversion of plasma cholinesterase activity values using three techniques

Directory of Open Access Journals (Sweden)

Jaime Carmona-Fonseca

2007-07-01

Full Text Available OBJETIVO: Determinar las relaciones matemáticas entre tres técnicas cuantitativas empleadas para medir la actividad de la colinesterasa plasmática, a partir de los valores de referencia ya establecidos para dos poblaciones de Antioquia, Colombia. MÉTODOS:Diseño descriptivo, transversal y prospectivo. Se conformaron dos muestras independientes representativas de la población laboral adulta (18-65 años, no expuesta a plaguicidas inhibidores de la colinesterasa y vinculada al Seguro Social, del valle de Aburrá (415 personas y del cercano oriente antioqueño (412 personas, del departamento de Antioquia, Colombia. La colinesterasa plasmática (EC 3.1.1.8 se midió mediante tres técnicas cuantitativas: Michel, EQM® y Monotest®. Se elaboraron ecuaciones de regresión que relacionaran entre sí los resultados de las tres técnicas estudiadas. RESULTADOS: Se definieron seis ecuaciones de regresión lineal simple que permitieron relacionar los resultados de las tres técnicas de medición de colinesterasa plasmática analizadas. La correlación entre las técnicas fue moderada (r: de 0,686 a 0,771, pero aumentó (r: de 0,744 a 0,811 al eliminar 12 (1,5% valores extremos. Las asociaciones entre las técnicas fueron altamente significativas (P OBJECTIVES: To determine mathematical correlations of three quantitative techniques to measure plasma cholinesterase, using reference values already established for two populations in the department of Antioquia, Colombia. METHODS: In this descriptive, cross-sectional, prospective study, two independent, representative samples of working adults (18 to 65 years old were examined. In both samples the adults worked for businesses associated with Colombia’s Social Security system. Adults in the two samples had not been exposed to cholinesterase-inhibiting pesticides. The samples were from two neighboring regions of the department of Antioquia: one sample (415 adults was from the Aburrá Valley, and the other

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)

Disturbance and topography shape nitrogen availability and δ15N over long-term forest succession

Science.gov (United States)

Forest disturbance and long-term succession can promote open N cycling that increases N loss and soil δ15N values. We examined soil and foliar patterns in N and δ15N, and soil N mineralization, across a topographically complex montane forest landscape influenced by human logging ...

Nitrogen and carbon isotopic composition of bone collagen from marine and terrestrial animals

International Nuclear Information System (INIS)

Schoeninger, M.J.; DeNiro, M.J.

1984-01-01

The stable nitrogen and carbon isotope ratios of bone collagen prepared from more than 100 animals representing 66 species of birds, fish, and mammals are presented. The delta 15 N values of bone collagen from animals that fed exclusively in the marine environment are, on average, 9 per mille more positive than those from animals that fed exclusively in the terrestrial environment: ranges for the two groups overlap by less than 1 per mille. Bone collagen delta 15 N values also serve to separate marine fish from the small number of freshwater fish we analyzed. The bone collagen delta 15 N values of birds and fish that spent part of their life cycles feeding in the marine environment and part in the freshwater environment are intermediate between those of animals that fed exclusively in one or the other system. Further, animals that fed at successive trophic levels in the marine and terrestrial environment are separated, on average, by a 3 per mille difference in the delta 15 N values of their bone collagen. Results are given and discussed. (author)

Correlation between the synthetic origin of methamphetamine samples and their 15N and 13C stable isotope ratios

International Nuclear Information System (INIS)

Billault, Isabelle; Courant, Frederique; Pasquereau, Leo; Derrien, Solene; Robins, Richard J.; Naulet, Norbert

2007-01-01

The active ingredient of ecstasy, N-methyl-3,4-methyldioxyphenylisopropylamine (MDMA) can be manufactured by a number of easy routes from simple precursors. We have synthesised 45 samples of MDMA following the five most common routes using N-precursors from 12 different origins and three different precursors for the aromatic moiety. The 13 C and 15 N contents of both the precursors and the MDMA samples derived therefrom were measured by isotope ratio mass spectrometry coupled to an elemental analyser (EA-IRMS). We show that within-pathway correlation between the 15 N content of the precursor and that of the derived MDMA can be strong but that no general pattern of correlation can be defined. Rather, it is evident that the δ 15 N values of MDMA are strongly influenced by a combination of the δ 15 N values of the source of nitrogen used, the route by which the MDMA is synthesised, and the experimental conditions employed. Multivariate analysis (PCA) based on the δ 15 N values of the synthetic MDMA and of the δ 15 N and δ 13 C values of the N-precursors leads to good discrimination between the majority of the reaction conditions tested

Casscf/ci Calculations for First Row Transition Metal Hydrides - the TIH(4-PHI), VH(5-DELTA), CRH(6-SIGMA-PLUS), MNH(7-SIGMA-PLUS), FEH(4,6-DELTA) and NIH(2-DELTA) States

Science.gov (United States)

Walch, S. P.; Bauschlicher, C. W., Jr.

1983-04-01

Calculations are performed for the predicted ground states of TiH(4-phi), VH(5-delta), CrH(6-sigma-plus), MnH(7-sigma-plus), Fett(4,6-delta) and NiH(2-delta). For FeH both the 6-delta and 4-delta states are studied, since both are likely candidates for the ground state. The ground state symmetries are predicted based on a combination of atomic coupling arguments and coupling of 4s(2)3d(n) and 4s(1)3d(n+1) terms in the molecular system. Electron correlation is included by a CASSCF/CI (SD) treatment. The CASSCF includes near-degeneracy effects, while correlation of the 3d electrons in included at the CI level.

Isotopic evaluations of dynamic and plant uptake of N in soil amended with 15N-labelled sewage sludge

International Nuclear Information System (INIS)

Kchaou, R.; Khelil, M. N.; Rejeb, S.; Gharbi, F.; Henchi, B.; Hernandez, T.; Destain, J. P.

2010-01-01

Field experiments were conducted to evaluate the use of a novel 15N isotope technique for comparing the dynamics of N derived from sewage sludge applied to sorghum to the dynamics of N derived from the commercial fertilizer, urea. The treatments included a control, sludge applied at three rates (3, 6 and 9 t/ha, or 113, 226 and 338 kg N/ha) and N-urea applied at three rates (150, 250 and 350 kg N/ha). Recovery of 15N -labelled sludge was similar for the different nitrogen rates applied , with a mean value of 27%. However, the recovery of 15N -urea decreased as the rate of N application increased (from 38% to 27%). Approximately 22% and 19% of the 15N from sludge and urea, respectively, remained in the 0-60 cm layer of soil, most of which was present in the 0-20 cm layer. Furthermore, losses of 15N -labelled fertilizer were not affected by the N fertilization source, and the greatest losses, which were measured in response to the highest N application rate, were 59%. (authors)

Synthesis of 15N-enriched fertilizers. Pt. II. Synthesis of 15N-enriched urea

International Nuclear Information System (INIS)

Bondassolli, J.A.; Trivelin, P.C.O.; Mortatti, J.; Victoria, R.L.

1988-01-01

The results of studies on the production of 15 N-urea through the reaction between 15 N-enriched anhidrous ammonia, carbon monoxide and sulfur, using hydrogen sulfite as a auto catalizers and methyl alcohol as a liquid reaction medium is presented. The influence of the quantities of reagents on final yield of synthesised urea were studied. Analysis of the cost of 5 Atoms % 15 N-enriched urea were made. (M.A.C.) [pt

Stringent tests of constrained Minimal Flavor Violation through {Delta}F=2 transitions

Energy Technology Data Exchange (ETDEWEB)

Buras, Andrzej J. [TUM-IAS, Garching (Germany); Girrbach, Jennifer [TUM, Physik Department, Garching (Germany)

2013-09-15

between F{sub B{sub s}} {radical}(B{sub B{sub s}}) and F{sub B{sub d}} {radical}(B{sub B{sub d}}), vertical stroke V{sub cb} vertical stroke, vertical stroke V{sub ub} vertical stroke and {gamma} that should be tested in the coming years. Typically F{sub B{sub s}} {radical}(B{sub B{sub s}}) and F{sub B{sub d}} {radical}(B{sub B{sub d}}) have to be lower than their present lattice values, while vertical stroke V{sub cb} vertical stroke has to be higher than its tree-level determination, with a significance depending on the evolution of their errors. Within the SM this would imply values for B(K{sup +} {yields} {pi}{sup +}{nu} anti {nu}) and B(K{sub L} {yields} {pi}{sup 0}{nu} anti {nu}) that are typically larger by (15-20) % than those presently quoted in the literature. The region in the space of these three parameters allowed by CMFV indicates tensions in this class of models and hints for the presence of new sources of flavor violation and/or new local operators in {Delta}F=2 data that are strongly suppressed in these models. As a byproduct we propose to reduce the present uncertainty in the charm contribution to {epsilon}{sub K} by using the experimental value of {Delta}M{sub K}. (orig.)

Carbon dynamics and CO2 and CH4 outgassing in the Mekong delta

Science.gov (United States)

Borges, Alberto V.; Abril, Gwenaël; Bouillon, Steven

2018-02-01

We report a data set of biogeochemical variables related to carbon cycling obtained in the three branches (Mỹ Tho, Hàm Luông, Cố Chiên) of the Mekong delta (Bến Tre province, Vietnam) in December 2003, April 2004, and October 2004. Both the inner estuary (upstream of the mouth) and the outer estuary (river plume) were sampled, as well as side channels. The values of the partial pressure of CO2 (pCO2) ranged between 232 and 4085 ppm, O2 saturation level (%O2) between 63 and 114 %, and CH4 between 2 and 2217 nmol L-1, within the ranges of values previously reported in temperate and tropical meso- and macro-tidal estuaries. Strong seasonal variations were observed. In the upper oligohaline estuary, low pCO2 (479-753 ppm) and high %O2 (98-106 %) values were observed in April 2004 most probably related to freshwater phytoplankton growth owing to low freshwater discharge (1400 m3 s-1) and increase in water residence time; during the two other sampling periods with a higher freshwater discharge (9300-17 900 m3 s-1), higher pCO2 (1895-2664 ppm) and lower %O2 (69-84 %) values were observed in the oligohaline part of the estuary. In October 2004, important phytoplankton growth occurred in the offshore part of the river plume as attested by changes in the contribution of particulate organic carbon (POC) to total suspended matter (TSM) (%POC) and the stable isotope composition of POC (δ13C-POC), possibly related to low TSM values (improvement of light conditions for phytoplankton development), leading to low pCO2 (232 ppm) and high %O2 (114 %) values. Water in the side channels in the Mekong delta was strongly impacted by inputs from the extensive shrimp farming ponds. The values of pCO2, CH4, %O2, and the stable isotope composition of dissolved inorganic carbon (δ13C-DIC) indicated intense organic matter degradation that was partly mediated by sulfate reduction in sediments, as revealed by the slope of total alkalinity (TA) and DIC covariations. The δ13C

Selfsimilar and fractal analysis of n-type delta-doped quasiregular GaAs quantum wells

International Nuclear Information System (INIS)

García-Cervantes, H.; Rodríguez-Vargas, I.

2014-01-01

We study the electronic structure of n-type delta-doped quantum wells in GaAs in which the multiple well system is built according to the Fibonacci sequence. The building blocks A and B correspond to delta-doped wells with impurities densities n 2DA and n 2DB , and the same well width. The Thomas-Fermi approximation, the semi-empirical sp 3 s* tight-binding model including spin, the Surface Green Function Matching method and the Transfer Matrix approach were implemented to obtain the confining potential, the electronic structure and the selfsimilarity of the spectrum. The fragmentation of the electronic spectra is observed whenever the building blocks A and B interact and it increases as the difference of impurities density between A and B increases as well. The wave function of the first sate of the fragmented bands presents critical characteristics, this is, it is not a localized state nor a extended one as well as it has selfsimilar features. So, the quasiregular characteristics are preserved irrespective of the complexity of the system and can affect the performance of devices based on these structures

Selfsimilar and fractal analysis of n-type delta-doped quasiregular GaAs quantum wells

Energy Technology Data Exchange (ETDEWEB)

García-Cervantes, H.; Rodríguez-Vargas, I. [Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad Esquina Con Paseo La Bufa S/N, 98060 Zacatecas, Zac. (Mexico)

2014-05-15

We study the electronic structure of n-type delta-doped quantum wells in GaAs in which the multiple well system is built according to the Fibonacci sequence. The building blocks A and B correspond to delta-doped wells with impurities densities n{sub 2DA} and n{sub 2DB}, and the same well width. The Thomas-Fermi approximation, the semi-empirical sp{sub 3}s* tight-binding model including spin, the Surface Green Function Matching method and the Transfer Matrix approach were implemented to obtain the confining potential, the electronic structure and the selfsimilarity of the spectrum. The fragmentation of the electronic spectra is observed whenever the building blocks A and B interact and it increases as the difference of impurities density between A and B increases as well. The wave function of the first sate of the fragmented bands presents critical characteristics, this is, it is not a localized state nor a extended one as well as it has selfsimilar features. So, the quasiregular characteristics are preserved irrespective of the complexity of the system and can affect the performance of devices based on these structures.

Unusually negative nitrogen isotopic compositions (δ15N) of mangroves and lichens in an oligotrophic, microbially-influenced ecosystem

Science.gov (United States)

Fogel, M. L.; Wooller, M. J.; Cheeseman, J.; Smallwood, B. J.; Roberts, Q.; Romero, I.; Meyers, M. J.

2008-12-01

Extremes in δ15N values in mangrove tissues and lichens (range =+4 to -22‰) were measured from a mangrove forest ecosystem located on Twin Cays, offshore islands in Belize, Central America. The N isotopic compositions and concentrations of NH4+/NH3 in porewater, rainwater, and atmospheric ammonia, and the δ15N of lichens, mangrove leaves, roots, stems, and wood were examined to study the biogeochemical processes important for establishing these unusual N isotopic ratios. Dwarfed Rhizophora mangle trees had the most negative δ15N, whereas fringing Rhizophora trees, the most positive δ15N values. Porewater ammonium concentrations had little relationship to N isotopic fractionation in mangrove tissues. In dwarfed mangroves, the δ15N of fine and coarse roots were 6-9‰ more positive than leaf tissue from the same tree, indicating different sources of N for root and leaf tissues. When P was added to dwarfed mangrove trees without added N, δ15N increased within one year from -12‰ to -2‰, approaching the δ15N of porewater ammonium (δ15N=+4‰). Isotopically depleted ammonia in the atmosphere (δ15N=-19‰) and in rainwater (δ15N=-10‰) were found on Twin Cays. We propose that foliar uptake of these atmospheric sources by P-stressed, dwarfed mangrove trees and lichens can explain their very negative δ15N values. In environments where P is limiting for growth, uptake of atmospheric N by Rhizophora mangle may be an important adaptive strategy.

Incorporation of Socio-Cultural Values in Damage Assessment Valuations of Contaminated Lands in the Niger Delta

Directory of Open Access Journals (Sweden)

Victor A. Akujuru

2014-07-01

Full Text Available Damages on contaminated land have been mostly assessed for developments subsisting on the land, neglecting the goods and services derived from the land which possess only socio-cultural values. This paper aims to ascertain the importance of socio-cultural values in the total economic value of contaminated land, drawing from the experience of a coastal community oil spillage in the Niger Delta. The paper examines what constitutes a valuable interest on contaminated land and how socio-cultural factors are valued in the damage assessment process. After reviewing the literature and decided cases, a questionnaire survey was conducted and a sample valuation report was analysed. It is concluded that there exists a socio-cultural interest on contaminated land which professional valuers do not reflect in damage assessment claims. It is recommended that any comprehensive damage assessment requires the incorporation of socio-cultural values in the valuations.

Prognostic value of monitoring tumour markers CA 15-3 and CEA during fulvestrant treatment

Directory of Open Access Journals (Sweden)

Locker Gottfried J

2006-03-01

Full Text Available Abstract Background At many centres tumour markers are used to detect disease recurrence and to monitor response to therapy in patients with advanced disease, although the real value of serial observation of marker levels remains disputed. In this study, we evaluated the prognostic value of tumour markers for predicting response (partial response [PR], stable disease [SD] ≥ 6 months, de novo disease progression (PD and secondary PD in patients receiving fulvestrant ('Faslodex' 250 mg/month for the treatment of metastatic breast cancer (MBC. Methods Changes in cancer antigen 15–3 (CA 15-3 and carcinoembryonic antigen (CEA were prospectively monitored (monthly and were also evaluated for the 3 months preceding secondary PD. Data from 67 patients with previously treated MBC participating in a Compassionate Use Programme were analysed. Results In patients with a PR (n = 7 [10.4%], a non-significant increase in CA 15-3 occurred during the first 6 months of treatment; CEA was significantly reduced (P = 0.0165. In patients with SD ≥ 6 months (n = 28 [41.8%], both CA 15-3 (P P = 0.0399 levels increased significantly after 6 months treatment. In those experiencing de novo PD (n = 32 [47.8%], CA 15-3 increased significantly (P P = 0.0002 during the same time period. Both CA 15-3 (P P Conclusion CA 15-3 increases in patients progressing on fulvestrant but may also increase in those experiencing clinical benefit; this should not be taken as a sign of PD without verification. Overall, both CA 15-3 and CEA appear to be poor prognostic markers for determining progression in patients receiving fulvestrant.

Inclusive production of. delta. /sup + +/(1232) in pn interactions at 19 GeV/c

Energy Technology Data Exchange (ETDEWEB)

Bakken, V.; Breivik, F.O.; Jacobsen, T.; Rudjord, A.L. (Oslo Univ. (Norway) Fysisk Inst.)

1982-12-21

We present a study of ..delta../sup + +/ production in pn interactions at 19 GeV/c, where the ..delta../sup + +/ is emitted in the protonlike (..delta..sub(F)/sup + +/) and neutron-like (..delta..sub(B)/sup + +/) c.m. hemispheres. The cross-section sigma(pn->..delta..sub(F)/sup + +/+X)=(3.09+-0.43) mb is about three times larger than sigma(pn->..delta..sub(B)/sup + +/+X)=(0.94+-0.34) mb. About 2/3 of ..delta..sub(F)/sup + +/ is peripherally produced with vertical stroketsub(p,..delta..)vertical stroke<1 (GeV/c)/sup 2/, while the cross-section for ..delta..sub(B)/sup + +/ production is nearly zero for vertical stroketsub(n,..delta..)vertical stroke<1 (GeV/c)/sup 2/. We have made a detailed study of the energy dependence of the reaction ap->..delta../sup + +/+X (a=p, anti p, n, ..pi..sup(+-), Ksup(+-)) for vertical stroketsub(p,..delta..)vertical stroke<1 (GeV/c)/sup 2/, by applying the same fitting procedure to extract the ..delta../sup + +/ cross-section to all available mass spectra. All the normalized cross-sections R=sigma(..delta../sup + +/)/sigmasub(inel) can be well described by R=R/sub 0/+R/sub 1/sup(a)psup(-..cap alpha..)sub(lab), where R/sub 0/ and ..cap alpha.. are the same for all reactions, while R/sub 1/sup(a) varies with the beam type a. The value of ..cap alpha.. is slightly below unity. The differential cross section of pn->..delta..sub(F)/sup + +/+X has been determined as a function of the variables t, t', x, y, psub(T)/sup 2/ and Msub(X)/sup 2/ both in the whole kinematical region and for vertical stroketsub(p,..delta..)vertical stroke<1 (GeV/c)/sup 2/. We show that the peripherally produced ..delta..sub(F)/sup + +/ is consistent with the dominance of the one-pion exchange mechanism. This follows from a study of the density matrix elements, the comparison of some properties of the system X with real ..pi../sup +/p data and from the results of a triple-Regge analysis.

Variation of natural 15N abundance of crops and soils in Japan with special reference to the effect of soil conditions and fertilizer application

International Nuclear Information System (INIS)

Yoneyama, Tadakatsu; Kouno, Kazumi; Yazaki, Jinya.

1990-01-01

The natural 15 N abundance (δ 15 N) of the crops subjected to long-term fertilizer treatments under paddy and upland conditions in the different experimental stations throughout Japan were analyzed. The δ 15 N values of the grains of paddy rice which were +6.3 per mille on the average in the fields without application of chemical fertilizers decreased by the treatment with chemical fertilizers. The average δ 15 N values of the upland crops were lower than those of paddy rice without application of N fertilizers. The δ 15 N values of upland crops decreased with the dose of chemical fertilizer N, but increased with the application of composts containing animal feces. The pot experiments using three soils showed that the δ 15 N values of paddy rice were higher than those of upland rice and sorghum and that these values were comparable to the δ 15 N values of ammonium and nitrate produced in the incubated soils, respectively. The δ 15 N values of fertilizer N absorbed by paddy rice were higher than those of fertilizer N, whereas the δ 15 N values of the fertilizer N in upland rice and sorghum were increased in the alluvial soils but decreased in Andosols as compared to those of fertilizer N applied. The δ 15 N values of the Andosols in Japan showed small variations, with an average value of +6.5 per mille, whereas those of alluvial soils in Japan showed large variations with an average value lower than that of Andosols. (author)

Effect of sodium acetate on the volumetric behaviour of some mono-, di-, and tri-saccharides in aqueous solutions over temperature range (288.15 to 318.15) K

Energy Technology Data Exchange (ETDEWEB)

Banipal, Parampaul K., E-mail: pkbanipal@yahoo.co [Department of Chemistry, Guru Nanak Dev University, Amritsar 143 005 (India); Singh, Vickramjeet [Department of Chemistry, Guru Nanak Dev University, Amritsar 143 005 (India); Banipal, Tarlok S. [Department of Applied Chemistry, Guru Nanak Dev University, Amritsar 143 005 (India)

2010-01-15

The standard partial molar volumes, V{sub 2}{sup 0} at infinite dilution of eight monosaccharides [D(+)-xylose, D(-)-arabinose, D(-)-ribose, L(-)-sorbose, D(-)-fructose, D(+)-galactose, D(+)-glucose, and D(+)-mannose], six disaccharides [D(+)-cellobiose, sucrose, D(+)-melibiose, D(+)-lactose monohydrate, D(+)-trehalose dihydrate, and D(+)-maltose monohydrate] and two trisaccharides [D(+)-melizitose and D(+)-raffinose pentahydrate] (molalities of saccharides range from (0.03 to 0.12) mol . kg{sup -1}) have been determined in water and in (0.5, 1.0, 2.0, and 3.0) mol . kg{sup -1} aqueous sodium acetate solutions at temperatures, T = (288.15, 298.15, 308.15, and 318.15) K from density measurements using a vibrating-tube digital densimeter. From these results, corresponding standard partial molar volumes of transfer, DELTA{sub t}V{sub 2}{sup 0} have been determined for the transfer of various saccharides from water to aqueous solutions of sodium acetate. Positive values of DELTA{sub t}V{sub 2}{sup 0} were obtained for most of the saccharides, whose magnitude increase with the concentration of sodium acetate as well as temperature. However, negative DELTA{sub t}V{sub 2}{sup 0} values were observed for L(-)-sorbose, D(-)-fructose and D(+)-xylose at lower concentrations of co-solute. The negative magnitude of DELTA{sub t}V{sub 2}{sup 0} values decrease with rise of temperature from (288.15 to 318.15) K. Pair and higher order volumetric interaction coefficients have been determined by using McMillan-Mayer theory. Partial molar expansion coefficients, (partial derivV{sub 2}{sup 0}/partial derivT){sub p} and the second derivatives (partial deriv{sup 2}V{sub 2}{sup 0}/partial derivT{sup 2}){sub p} have also been estimated. These parameters have been utilized to understand various mixing effects in aqueous solutions due to the interactions between solute (saccharide) and co-solute (sodium acetate).

Disturbance and topography shape nitrogen availability and ä15N over long-term forest succession

Science.gov (United States)

Steven S. Perakis; Alan J. Tepley; Jana E. Compton

2015-01-01

Forest disturbance and long-term succession towards old-growth are thought to increase nitrogen (N) availability and N loss, which should increase soil ä15N values. We examined soil and foliar patterns in N and ä15N, and soil N mineralization, across 800 years of forest succession in a topographically complex montane...

15N Hyperpolarization of Imidazole-15N2 for Magnetic Resonance pH Sensing via SABRE-SHEATH.

Science.gov (United States)

Shchepin, Roman V; Barskiy, Danila A; Coffey, Aaron M; Theis, Thomas; Shi, Fan; Warren, Warren S; Goodson, Boyd M; Chekmenev, Eduard Y

2016-06-24

15 N nuclear spins of imidazole- 15 N 2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A 15 N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole- 15 N 2 in methanol:aqueous buffer (∼1:1). Proton binding to a 15 N site of imidazole occurs at physiological pH (p K a ∼ 7.0), and the binding event changes the 15 N isotropic chemical shift by ∼30 ppm. These properties are ideal for in vivo pH sensing. Additionally, imidazoles have low toxicity and are readily incorporated into a wide range of biomolecules. 15 N-Imidazole SABRE-SHEATH hyperpolarization potentially enables pH sensing on scales ranging from peptide and protein molecules to living organisms.

Nitrogen source tracking with δ15N content of coastal wetland plants in Hawaii

Science.gov (United States)

Gregory L. Bruland; Richard A.. Mackenzie

2010-01-01

Inter- and intra-site comparisons of the nitrogen (N) stable isotope composition of wetland plant species have been used to identify sources of N in coastal areas. In this study, we compared δ15N values from different herbaceous wetland plants across 34 different coastal wetlands from the five main Hawaiian Islands and investigated relationships of δ15N with...

Environmental isotopes (N, S, C, O, D) to determine natural attenuation processes in nitrate contaminated waters: Example of Osona (NE Spain)

Energy Technology Data Exchange (ETDEWEB)

Vitoria, Laura [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain)], E-mail: lvitoria@ub.edu; Soler, Albert; Canals, Angels [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain); Otero, Neus [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain); Departament de Geologia Ambiental, Institut de Ciencies de la Terra ' Jaume Almera' , CSIC C/Lluis Sole i Sabaris s/n, Barcelona 08028 (Spain)

2008-12-15

Nitrate-contaminated groundwater from an aquifer in the Osona region (NE Spain) was chemically and isotopically ({delta}{sup 15}N{sub NO{sub 3}},{delta}{sup 18}O{sub NO{sub 3}},{delta}{sup 34}S{sub SO{sub 4}},{delta}{sup 18}O{sub SO{sub 4}}, {delta}D, {delta}{sup 18}O{sub H{sub 2}}{sub O} and {delta}{sup 13}C{sub DIC}) characterized. Diffuse- NO{sub 3}{sup -} contamination reached values of 366 mg/L. Nearly 75% of the 37 sampled sites had higher concentrations than the 50 mg/L in NO{sub 3}{sup -} limit for drinking water. To identify the source of pollution {delta}{sup 15}N{sub NO{sub 3}} and {delta}{sup 18}O{sub NO{sub 3}} were used with results, for most samples, in the range of pig manure NO{sub 3}{sup -}. Nitrification processes were evaluated by means of the {delta}{sup 18}O of NO{sub 3}{sup -} and water. Isotopic data suggested that natural attenuation of NO{sub 3}{sup -} was taking place. This process was confirmed using the {delta}{sup 18}O{sub NO{sub 3}} coupled with the NO{sub 3}{sup -}/Cl{sup -} ratio, avoiding the influence of continuous NO{sub 3}{sup -} inputs. A further insight on denitrification processes was obtained by analyzing the ions involved in denitrification reactions. Although the role of organic matter oxidation could neither be confirmed nor discarded, this approach showed a link between denitrification and pyrite oxidation. Therefore, in areas with no adequate infrastructure (e.g. multipiezometers), such as the one studied, this approach could be useful for implementing better water management.

Determination of the positions and residues of the. delta. /sup + +/ and. delta. /sup 0/ poles. [Phase shifts,coulomb corrections

Energy Technology Data Exchange (ETDEWEB)

Vasan, S S [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics

1976-04-19

The poles and the associated residues in the ..pi..N P/sub 33/ amplitude corresponding to the resonances ..delta../sup + +/ and ..delta../sup 0/ are determined by fitting the ..pi../sup +/p and ..pi../sup -/p hadronic phase shifts from the Carter 73 analysis. The ..delta../sup + +/ and ..delta../sup 0/ pole positions are determined also from the nuclear phase shifts, these being the phase shifts made up of the hadronic phase shifts plus the Coulomb corrections. The pole positions obtained from the two sets of phase shifts are different, the differences being larger in the case of the ..delta../sup + +/.

Unusually negative nitrogen isotopic compositions (δ15N of mangroves and lichens in an oligotrophic, microbially-influenced ecosystem

Directory of Open Access Journals (Sweden)

I. Romero

2008-12-01

Full Text Available Extremes in δ15N values in mangrove tissues and lichens (range =+4 to −22‰ were measured from a mangrove forest ecosystem located on Twin Cays, offshore islands in Belize, Central America. The N isotopic compositions and concentrations of NH4+/NH3 in porewater, rainwater, and atmospheric ammonia, and the δ15N of lichens, mangrove leaves, roots, stems, and wood were examined to study the biogeochemical processes important for establishing these unusual N isotopic ratios. Dwarfed Rhizophora mangle trees had the most negative δ15N, whereas fringing Rhizophora trees, the most positive δ15N values. Porewater ammonium concentrations had little relationship to N isotopic fractionation in mangrove tissues. In dwarfed mangroves, the δ15N of fine and coarse roots were 6–9‰ more positive than leaf tissue from the same tree, indicating different sources of N for root and leaf tissues. When P was added to dwarfed mangrove trees without added N, δ15N increased within one year from −12‰ to −2‰, approaching the δ15N of porewater ammonium (δ15N=+4‰. Isotopically depleted ammonia in the atmosphere (δ15N=−19‰ and in rainwater (δ15N=−10‰ were found on Twin Cays. We propose that foliar uptake of these atmospheric sources by P-stressed, dwarfed mangrove trees and lichens can explain their very negative δ15N values. In environments where P is limiting for growth, uptake of atmospheric N by Rhizophora mangle may be an important adaptive strategy.

Transport Measurements on NEODYMIUM(1.85) CERIUM(.15) Copper OXYGEN(4-DELTA) Thin Films

Science.gov (United States)

Kussmaul, Andreas

1992-01-01

This work describes the synthesis and the study of the transport properties of thin films of Nd _{1.85}Ce_{.15 }CuO_{4-delta} carried out respectively at the IBM T. J. Watson Research Center in collaboration with Dr. A. Gupta, and at the Francis Bitter National Magnet Laboratory under the direction of Dr. P. M. Tedrow. The thin films were prepared by laser ablation of a stoichiometric target on heated substrates in a reactive ambient. The influence of the deposition parameters was studied, and the use of a nitreous oxide ambient was found to yield a clear improvement of the sample quality. The transport properties of the films were measured at low temperatures and in high magnetic fields. Non superconducting samples showed a strong, highly anisotropic, negative magnetoresistance that is consistent with two dimensional weak-localization. Superconducting samples show two dimensional fluctuation effects above T_{c}. The theory of fluctuations in a magnetic field was used to extract the position of H_{c2} (in the perpendicular direction) in the broad and almost featureless resistive transition, and the extracted values were fit to the theory of dirty superconductors. The angular dependence of the resistive transition was studied close to T _{c} and found to be somewhat better described by a two-dimensional model. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.).

Comparison of 15N- and 13C-determined parameters of mobility in melittin

International Nuclear Information System (INIS)

Zhu Lingyang; Prendergast, Franklyn G.; Kemple, Marvin D.

1998-01-01

Backbone and tryptophan side-chain mobilities in the 26-residue, cytolytic peptide melittin (MLT) were investigated by 15 N and 13 C NMR. Specifically, inverse-detected 15 N T 1 and steady-state NOE measurements were made at 30 and 51 MHz on MLT at 22 deg. C enriched with 15 N at six amide positions and in the Trp 19 side chain. Both the disordered MLT monomer (1.2 mM peptide at pH 3.6 in neat water) and α-helical MLT tetramer (4.0 mM peptide at pH 5.2 in 150 mM phosphate buffer) were examined. The relaxation data were analyzed in terms of the Lipari and Szabo model-free formalism with three parameters: τ m , the correlation time for the overall rotation; S 2 , a site-specific order parameter which is a measure of the amplitude of the internal motion; and τ e , a local, effective correlation time of the internal motion. A comparison was made of motional parameters from the 15 N measurements and from 13 C measurements on MLT, the latter having been made here and previously [Kemple et al. (1997) Biochemistry, 36, 1678-1688]. τ m and τ e values were consistent from data on the two nuclei. In the MLT monomer, S 2 values for the backbone N-H and Cα-H vectors in the same residue were similar in value but in the tetramer the N-H order parameters were about 0.2 units larger than the Cα-H order parameters. The Trp side-chain N-H and C-H order parameters, and τ e values were generally similar in both the monomer and tetramer. Implications of these results regarding the dynamics of MLT are examined

Investigation of the metabolism of colostomized laying hens with 15N-labelled wheat. 6

International Nuclear Information System (INIS)

Gruhn, K.; Hennig, A.

1980-01-01

Three colostomized laving hens received 40 g 15 N-labelled wheat with 20.13 atom-% 15 N excess ( 15 N'), 19.18 atom-% 15 N'-lysine, 18.17 atom-% 15 N'-histidine and 20.43 atom-% 15 N'-arginine per day over a period of four days. After having received the same non-labelled feed ration on the following four days, the hens were slaughtered. The incorporation and distribution of 15 N' in the total nitrogen and the nitrogen of the basic amino acids was determined in liver, kidneys, muscles, bones and the remaining carcass (excluding blood, digestive tract and genital organs). The quota of nitrogen of natural isotope frequency ( 14 N) of the total 14 N of the hens' carcasses was 47% in the muscles, 14% in the bones and 20% in the feathers; the relative 15 N' values were 37%, 8% and 1%, resp. The atom-% 15 N' in the kidneys was twice as much as in the liver four days after the last 15 N' application. The average percentage of the nitrogen in the three basic amino acids of the total nitrogen in the tissues and organs (excluding feathers) is 25% concerning both 14 N and 15 N'. The 15N' balance revealed that in hen 1 100%, in hen 2 102% and in hen 3 101% of the consumed wheat 15 N' were found. (author)

The effect of noncollinearity of 15N-1H dipolar and 15N CSA tensors and rotational anisotropy on 15N relaxation, CSA/dipolar cross correlation, and TROSY

International Nuclear Information System (INIS)

Fushman, David; Cowburn, David

1999-01-01

Current approaches to 15N relaxation in proteins assume that the 15N-1H dipolar and 15N CSA tensors are collinear. We show theoretically that, when there is significant anisotropy of molecular rotation, different orientations of the two tensors, experimentally observed in proteins, nucleic acids, and small peptides, will result in differences in site- specific correlation functions and spectral densities. The standard treatments of the rates of longitudinal and transverse relaxation of amide 15N nuclei, of the 15N CSA/15N-1H dipolar cross correlation, and of the TROSY experiment are extended to account for the effect of noncollinearity of the 15N-1H dipolar and 15N CSA (chemical shift anisotropy) tensors. This effect, proportional to the degree of anisotropy of the overall motion, (D-parallel /D-perpendicular -1), is sensitive to the relative orientation of the two tensors and to the orientation of the peptide plane with respect to the diffusion coordinate frame. The effect is negligible at small degrees of anisotropy, but is predicted to become significant for D-parallel /D-perpendicular ≥1.5, and at high magnetic fields. The effect of noncollinearity of 15N CSA and 15N-1H dipolar interaction is sensitive to both gross (hydrodynamic) properties and atomic-level details of protein structure. Incorporation of this effect into relaxation data analysis is likely to improve both precision and accuracy of the derived characteristics of protein dynamics, especially at high magnetic fields and for molecules with a high degree of anisotropy of the overall motion. The effect will also make TROSY efficiency dependent on local orientation in moderately anisotropic systems

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

Science.gov (United States)

Pedentchouk, Nikolai; Mihailova, Alina; Abbado, Dimitri

2014-05-01

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

Production of 15N-enriched nitric acid (H15NO3

Directory of Open Access Journals (Sweden)

C. R. Sant Ana Filho

2008-12-01

Full Text Available Techniques that employ 15N have proved to be an important tool in many areas of the agronomic and biomedical sciences. Nevertheless, their use is limited by methodological difficulties and by the price of compounds in the international market. Nitric compounds (15NO3- have attracted the interest of researchers. However, these compounds are not currently produced in Brazil. Thus, in the present work H15NO3 was obtained from the oxidation of anhydrous 15NH3. The method we used differs from the industrial process in that the absorption tower is replaced with a polytetrafluoroethylene-lined, stainless-steel hydration reactor. The process output was evaluated based on the following parameters: reaction temperature; ratio of reagents; pressure and flow of 15NH3(g through the catalyst (Pt/Rh. The results showed that, at the best conditions (500 ºC; 50 % excess O2; 0.4 MPa; and 3.39 g.min-1 of 15NH3, a conversion percentage (N-15NH3 to N-15NO3- of 62.2 %, an overall nitrogen balance (N-15NH3 + N-15NO3- of 86.8 %, and purity higher than 99 % could be obtained.

Synthesis of triated N1'-alkyl derivatives of the delta opioid receptor ligand naltrindole

International Nuclear Information System (INIS)

Lever, J.R.; Johnson, S.M.

1997-01-01

Tritiated N1'-methyl and N1'-ethyl analogues of naltrindole (NTI) have been synthesized for evaluation as radioligands for studies of delta opioid receptors. The two N1'-alkyl-5',7'-dibromoNTI precursors for radiolabeling were prepared by base-promoted alkylation of 2,4-dibromophenylhydrazine with either iodomethane or iodoethane followed by condensation with naltrexone using the Fischer indole synthesis. Catalytic debromotritiation followed by HPLC purification afforded [ 3 H]MeNTI (17.3 Ci/mmol) and [ 3 H]EtNTI (22.5 Ci/mmol) with high chemical and radiochemical purities (≥ 99.8%). (author)

Effect of Carbonate Matrix on δ15N Analysis Tested for Simple Bulk Combustion on Coupled Elemental Analyzer-GC-IRMS

Science.gov (United States)

Saxena, D.; Grossman, E. L.; Maupin, C. R.; Roark, B.; O'Dea, A.

2016-12-01

Nitrogen isotopes (15N/14N) have been extensively used to reconstruct trophic structure, anthropogenic nutrient loading, ecosystem dynamics, and nutrient cycling in terrestrial and marine systems. Extending similar efforts to deep time is critical to investigate sources and fluxes of nutrients in past oceans, and explore causes of biotic turnover. To test the fidelity of N-isotope analyses of biogenic carbonate samples by simple bulk combustion, we performed two sets of experiments involving varying proportions of reagent CaCO3 (0, 2, 35 mg) and three organic standards (3.7-47.2 µg) viz. USGS40 (δ15NAir = -4.52‰), USGS41 (δ15NAir = +47.57‰), and in-house standard Rice (δ15NAir = +1.18‰). At high N contents (15-47.2 µg), δ15N values for CaCO3-amended samples are consistently either 0.5‰ higher (USGS40, -4.5‰), equivalent (Rice, 1.2‰), or 0.5‰ lower (USGS41, 47.6‰) relative to unamended samples. The difference thus depends on the δ15N of the standard relative to air. With decreasing N content (10-15 µg), δ15N values for CaCO3-amended samples diverge from expected values, with 35 mg CaCO3 samples diverging at the highest N content and 0 mg CaCO3 samples at the lowest (10 µg). The latter matches the lower sample-size limit for accurate measurement under the experimental conditions. At very low sample size (3.7-10 µg), all unamended standards show decreasing δ15N with decreasing N content, presumably because of non-linearity in instrument electronics and ion source behavior. The δ15N values of amended USGS41 also decrease with decreasing N content, but those of amended USGS40 and Rice samples increase, with samples containing more CaCO3 (35 versus 2 mg) showing greater deviation from expected values. Potential causes for deviation in δ15N values with CaCO3 amendments include N2 contamination from tin capsules and reagent CaCO3, and incomplete combustion due to energy consumption during CaCO3 decomposition. While tin capsules and reagent Ca

Application Value of Slider-Crank Mechanism in Pick-and-Place Operation of Delta Robot

Directory of Open Access Journals (Sweden)

Zhe QIN

2018-01-01

Full Text Available By absorbing the advantages of the rotary-driven Delta robot and linear-driven Delta robot, a Delta robot for pick-and-place operation that forms a crank-slider at the drive joint is designed.To take the most common gate shaped curve in Cartesian space as the motion trail of robotic pick-and-place operation, according to the kinematics inverse solution theory of Delta robot, this thesis mainly solves the output angular velocity of robot-driven joint. Establishing the static transfer mathematical model and solving the forced condition of driving joint. The simulation analysis show that after the upper slider-crank mechanism is connected to the driving joint, the angular velocity of the driving joint changes suddenly, which caused a rigid impact on the robot in the picking and releasing operation, though the force of the driving joint can be made smaller.

Initial isotopic geochemistry ({delta} 18 O, {delta} D) of fluids from wells of the Los Humeros, Pue., geothermal field; Geoquimica isotopica ({delta} 18 O, {delta} D) inicial de fluidos de pozos del campo geotermico de Los Humeros, Pue.

Energy Technology Data Exchange (ETDEWEB)

Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)]. E-mail: rmb@iie.org.mx; Ramirez Montes, Miguel; Tovar Aguado, Rigoberto [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)

2010-01-15

Isotopic data ({delta} 18 O, {delta} D) from fluids from production wells at the Los Humeros, Pue., geothermal field were analyzed to investigate the possible origin of these fluids and the dominant processes of the reservoir at its initial state. According to pre-exploitation data, it is suggested the Los Humeros reservoir fluids are made of a mixture of meteoric water of very light isotopic composition (paleo-fluids) and andesitic water. The relationship {delta} D vs {delta} 18 O from pre-exploitation data indicates the produced fluids are composed of a mixture of (at least) two fluids with distinct isotopic compositions. At the more enriched end of the mixing relationship are the isotopic compositions of the wells H-23 and H-18 (located in the southern area of the field), while the lighter fluids were found in well H-16 (originally) and then in well H-16 (repaired). It was found that the liquid phases of deep wells are more enriched in {delta} 18 O while the shallow wells present lower values, suggesting a convection process at the initial state. Based on this isotopic profile, it is considered that even the production depths of the wells H-1, H-12 and H-16 (repaired) are just about the same, but their respective isotopic compositions are quite different. The {delta} 18 O value for well H-16 (repaired) seems to be that of condensate steam, while the corresponding values for wells H-1 and H-12 fall within the value interval of the deep wells (H-23). This suggests wells H-1 and H-12 are collecting very deep fluids enriched in {delta} 18 O. These results could be useful in creating a conceptual model of the reservoir. [Spanish] Se analizaron datos isotopicos ({delta}18 O, {delta}D) de los fluidos de pozos productores del campo geotermico de Los Humeros, Pue., para investigar el posible origen de los fluidos asi como los procesos dominantes del yacimiento en su estado inicial. De acuerdo con datos previos a la explotacion, se plantea que los fluidos del yacimiento

QCD in the {delta}-regime

Energy Technology Data Exchange (ETDEWEB)

Bietenholz, W. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Ciencias Nucleares; Cundy, N. [Seoul National Univ. (Korea, Republic of). Lattice Gauge Theory Research Center; Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, R.; Zanotti, J.M. [Edinburgh Univ. (United Kingdom). School of Physics; Nakamura, Y. [Tsukuba Univ., Ibaraki (Japan). Center for Computational Sciences; Pleiter, D. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Schierholz, G. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2011-03-15

The {delta}-regime of QCD is characterised by light quarks in a small spatial box, but a large extent in (Euclidean) time. In this setting a specific variant of chiral perturbation theory - the {delta}-expansion - applies, based on a quantum mechanical treatment of the quasi onedimensional system. In particular, for vanishing quark masses one obtains a residual pion mass M{sup R}{sub {pi}}, which has been computed to the third order in the {delta}-expansion. A comparison with numerical measurements of this residual mass allows for a new determination of some Low Energy Constants, which appear in the chiral Lagrangian. We first review the attempts to simulate 2-flavour QCD directly in the {delta}-regime. This is very tedious, but results compatible with the predictions for M{sup R}{sub {pi}} have been obtained. Then we show that an extrapolation of pion masses measured in a larger volume towards the {delta}-regime leads to good agreement with the theoretical predictions. From those results, we also extract a value for the (controversial) sub-leading Low Energy Constant anti l{sub 3}. (orig.)

Conceptualizing delta forms and processes in Arctic coastal environments

DEFF Research Database (Denmark)

Bendixen, Mette; Kroon, Aart

2017-01-01

Climate warming in the Arctic directly causes two opposite changes in Arctic coastal systems: increased melt-water discharge through rivers induces extra influx of sediments and extended open water season increases wave impact which reworks and erodes the shores. A shoreline change analysis along...... and popped up as hotspots. The Tuapaat delta and Skansen delta showed large progradation rates (1.5 and 7m/yr) and migration of the adjacent barriers and spits. The dynamic behavior at the delta mouths was mainly caused by classic delta channel lobe switching at one delta (Tuapaat), and by a breach...... of the fringing spit at the other delta (Skansen). The longshore and cross-shore transports are responsible for reworking the sediment with a result of migrating delta mouths and adjacent subaqueous mouth bars. Seaward progradation of the deltas is limited due to the steep nature of the bathymetry in Disko Bay...

Ratio of deuterium to hydrogen in interstellar space. IV. The lines of sight to delta, epsilon, and iota Orionis

International Nuclear Information System (INIS)

Laurent, C.; Vidal-Madjar, A.; York, D.G.

1979-01-01

We have analyzed the deuterium absorption features in the spectra of delta, epsilon, and iota Ori obtained with Copernicus. The iota Ori line-of-sight analysis, which is quite detailed because of the high-velocity H I components superposed on the deuterium features, gives a D/H ratio (which is uncertain because of a complex profile) of 1.4 x 10 -5 . We determined a D/H ratio of the order of 7 x 10 -6 for delta and epsilon Ori. For the complex line profiles involved, one may regard this as a formal lower limit. Several attempts were made to increase the ratio N (DI)/N (H I) in the context of reasonable models for the line of sight, but with no success; we therefore regard the derived values as actual values, not lower limits. Since our derived value is an average on the line of sight, we cannot rule out the possibility that the true ratios N (D I)/N (H I) in individual nearby components (Δν -1 ) differ from the mean values. Our mean value for these two directions is lower by a factor of 4 than our best value for the zeta Pup line of sight

Discrimination between ginseng from Korea and China by light stable isotope analysis

Energy Technology Data Exchange (ETDEWEB)

Horacek, Micha, E-mail: micha.horacek@ait.ac.at [Department of Environmental Resources and Technology, Austrian Institute of Technology, 2444 Seibersdorf (Austria); Min, Ji-Sook; Heo, Sang-Cheol [National Institute of Scientific Investigation, 331-1 Shinwol-7dong, Yangcheon-ku, Seoul 158-707 (Korea, Republic of); Soja, Gerhard [Department of Environmental Resources and Technology, Austrian Institute of Technology, 2444 Seibersdorf (Austria)

2010-12-03

Ginseng is a health food and traditional medicine highly valued in Asia. Ginseng from certain origins is higher valued than from other origins, so that a reliable method for differentiation of geographical origin is important for the economics of ginseng production. To discriminate between ginseng samples from South Korea and PR China, 29 samples have been analyzed for the isotopic composition of the elements H, C and N. The results showed {delta}{sup 2}H values between -94 and -79 per mille , for {delta}{sup 13}C -27.9 to -23.7 per mille and for {delta}{sup 15}N 1.3-5.4 per mille for Chinese ginseng. Korean ginseng gave {delta}{sup 2}H ratios between -91 and -69 per mille , {delta}{sup 13}C ratios between -31.2 and -22.4 per mille and {delta}{sup 15}N ratios between -2.4 and +7 per mille . Despite the overlap between the values for individual isotopes, a combination of the isotope systems gave a reasonable differentiation between the two geographic origins. Especially the statistically significant difference in {delta}{sup 2}H ratios facilitated the differentiation between Korean and Chinese ginseng samples.

Nitrogen-15-labeled deoxynucleosides. 3. Synthesis of [3-15N]-2'-deoxyadenosine

International Nuclear Information System (INIS)

Rhee, Young-Sook; Jones, R.A.

1990-01-01

The synthesis of [3- 15 N]-labeled adenine has been reported by several groups. Each of these syntheses followed essentially the same route, in which the 15 N is introduced by nitration of 4-bromoimidazole under forcing conditions using [ 15 N]-HNO 3 . The authors have devised an alternate route which uses an azo coupling reaction for introduction of the 15 N and proceeds through the intermediacy of [5- 15 N]-labeled 5-aminoimidazole-4-carboxamide (AICA). An unrelated route to the [5- 15 N]-labeled 5-amino-imidazole ribonucleoside (AIRs) was recently reported. AICA is a versatile precursor, which is most commonly used for entry into the guanine or isoguanine families, although it is usually used as the AICA-riboside rather than the heterocycle itself. The authors have found that AICA also can be used for the adenine family by cyclization to hypoxanthine using diethoxymethyl acetate in DMF at reflux. Although these conditions are more vigorous than those required for cyclization of 4,5-diaminopyrimidines using this reagent, the reaction works well. In addition, they report high-yield enzymatic conversion of [3- 15 N]-adenine to [3- 15 N]-2'-deoxyadenosine

Improved γ-linolenic acid production in Mucor circinelloides by homologous overexpressing of delta-12 and delta-6 desaturases.

Science.gov (United States)

Zhang, Yao; Luan, Xiao; Zhang, Huaiyuan; Garre, Victoriano; Song, Yuanda; Ratledge, Colin

2017-06-21

γ-Linolenic acid (GLA) is important because of its nutritional value and medicinal applications. Although the biosynthetic pathways of some plant and microbial GLA have been deciphered, current understanding of the correlation between desaturases and GLA synthesis in oleaginous fungi is incomplete. In previous work, we found that a large amount of oleic acid (OA) had not been converted to linoleic acid (LA) or GLA in Mucor circinelloides CBS 277.49, which may be due to inadequate activities of the delta-12 or delta-6 desaturases, and thus leading to the accumulation of OA and LA. Thus, it is necessary to explore the main contributing factor during the process of GLA biosynthesis in M. circinelloides. To enhance GLA production in M. circinelloides, homologous overexpression of delta-12 and two delta-6 desaturases (named delta-6-1 and delta-6-2, respectively) were analyzed. When delta-6 desaturase were overexpressed in M. circinelloides, up to 43% GLA was produced in the total fatty acids, and the yield of GLA reached 180 mg/l, which were, respectively, 38 and 33% higher than the control strain. These findings revealed that delta-6 desaturase (especially for delta-6-1 desaturase) plays an important role in GLA synthesis by M. circinelloides. The strain overexpressing delta-6-1 desaturase may have potential application in microbial GLA production.

The CN/C15N isotopic ratio towards dark clouds

Science.gov (United States)

Hily-Blant, P.; Pineau des Forêts, G.; Faure, A.; Le Gal, R.; Padovani, M.

2013-09-01

Understanding the origin of the composition of solar system cosmomaterials is a central question, not only in the cosmochemistry and astrochemistry fields, and requires various approaches to be combined. Measurements of isotopic ratios in cometary materials provide strong constraints on the content of the protosolar nebula. Their relation with the composition of the parental dark clouds is, however, still very elusive. In this paper, we bring new constraints based on the isotopic composition of nitrogen in dark clouds, with the aim of understanding the chemical processes that are responsible for the observed isotopic ratios. We have observed and detected the fundamental rotational transition of C15N towards two starless dark clouds, L1544 and L1498. We were able to derive the column density ratio of C15N over 13CN towards the same clouds and obtain the CN/C15N isotopic ratios, which were found to be 500 ± 75 for both L1544 and L1498. These values are therefore marginally consistent with the protosolar value of 441. Moreover, this ratio is larger than the isotopic ratio of nitrogen measured in HCN. In addition, we present model calculations of the chemical fractionation of nitrogen in dark clouds, which make it possible to understand how CN can be deprived of 15N and HCN can simultaneously be enriched in heavy nitrogen. The non-fractionation of N2H+, however, remains an open issue, and we propose some chemical way of alleviating the discrepancy between model predictions and the observed ratios. Appendices are available in electronic form at http://www.aanda.orgThe reduced spectra (in FITS format) are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A65

The contamination of commercial 15N2 gas stocks with 15N-labeled nitrate and ammonium and consequences for nitrogen fixation measurements.

Science.gov (United States)

Dabundo, Richard; Lehmann, Moritz F; Treibergs, Lija; Tobias, Craig R; Altabet, Mark A; Moisander, Pia H; Granger, Julie

2014-01-01

We report on the contamination of commercial 15-nitrogen (15N) N2 gas stocks with 15N-enriched ammonium, nitrate and/or nitrite, and nitrous oxide. 15N2 gas is used to estimate N2 fixation rates from incubations of environmental samples by monitoring the incorporation of isotopically labeled 15N2 into organic matter. However, the microbial assimilation of bioavailable 15N-labeled N2 gas contaminants, nitrate, nitrite, and ammonium, is liable to lead to the inflation or false detection of N2 fixation rates. 15N2 gas procured from three major suppliers was analyzed for the presence of these 15N-contaminants. Substantial concentrations of 15N-contaminants were detected in four Sigma-Aldrich 15N2 lecture bottles from two discrete batch syntheses. Per mole of 15N2 gas, 34 to 1900 µmoles of 15N-ammonium, 1.8 to 420 µmoles of 15N-nitrate/nitrite, and ≥21 µmoles of 15N-nitrous oxide were detected. One 15N2 lecture bottle from Campro Scientific contained ≥11 µmoles of 15N-nitrous oxide per mole of 15N2 gas, and no detected 15N-nitrate/nitrite at the given experimental 15N2 tracer dilutions. Two Cambridge Isotopes lecture bottles from discrete batch syntheses contained ≥0.81 µmoles 15N-nitrous oxide per mole 15N2, and trace concentrations of 15N-ammonium and 15N-nitrate/nitrite. 15N2 gas equilibrated cultures of the green algae Dunaliella tertiolecta confirmed that the 15N-contaminants are assimilable. A finite-differencing model parameterized using oceanic field conditions typical of N2 fixation assays suggests that the degree of detected 15N-ammonium contamination could yield inferred N2 fixation rates ranging from undetectable, detected in field assays. These results indicate that past reports of N2 fixation should be interpreted with caution, and demonstrate that the purity of commercial 15N2 gas must be ensured prior to use in future N2 fixation rate determinations.

Diet-tissue stable isotope (Δ(13)C and Δ(15)N) discrimination factors for multiple tissues from terrestrial reptiles.

Science.gov (United States)

Steinitz, Ronnie; Lemm, Jeffrey M; Pasachnik, Stesha A; Kurle, Carolyn M

2016-01-15

Stable isotope analysis is a powerful tool for reconstructing trophic interactions to better understand drivers of community ecology. Taxon-specific stable isotope discrimination factors contribute to the best use of this tool. We determined the first Δ(13)C and Δ(15)N values for Rock Iguanas (Cyclura spp.) to better understand isotopic fractionation and estimate wild reptile foraging ecology. The Δ(13)C and Δ(15)N values between diet and skin, blood, and scat were determined from juvenile and adult iguanas held for 1 year on a known diet. We measured relationships between iguana discrimination factors and size/age and quantified effects of lipid extraction and acid treatment on stable isotope values from iguana tissues. Isotopic and elemental compositions were determined by Dumas combustion using an elemental analyzer coupled to an isotope ratio mass spectrometer using standards of known composition. The Δ(13)C and Δ(15)N values ranged from -2.5 to +6.5‰ and +2.2 to +7.5‰, respectively, with some differences among tissues and between juveniles and adults. The Δ(13)C values from blood and skin differed among species, but not the Δ(15)N values. The Δ(13)C values from blood and skin and Δ(15)N values from blood were positively correlated with size/age. The Δ(13)C values from scat were negatively correlated with size (not age). Treatment with HCl (scat) and lipid extraction (skin) did not affect the isotope values. These results should aid in the understanding of processes driving stable carbon and nitrogen isotope discrimination factors in reptiles. We provide estimates of Δ(13)C and Δ(15)N values and linear relationships between iguana size/age and discrimination factors for the best interpretation of wild reptile foraging ecology. Copyright © 2015 John Wiley & Sons, Ltd.

The Localizing Value Of Focal Delta Slowing In Temporal Lobe ...

African Journals Online (AJOL)

Slow wave EEG had a higher marginal probability than neuropsychological assessment of predicting the focus, and was equally effective as other investigative methods. Conclusion These results suggest that focal temporal delta slowing is useful in the localization of epileptogenic foci. There was no discordance with the ...

Stable isotopes document the trophic structure of a deep-sea cephalopod assemblage including giant octopod and giant squid.

Science.gov (United States)

Cherel, Y; Ridoux, V; Spitz, J; Richard, P

2009-06-23

Although deep-sea cephalopods are key marine organims, their feeding ecology remains essentially unknown. Here, we report for the first time the trophic structure of an assemblage of these animals (19 species) by measuring the isotopic signature of wings of their lower beaks, which accumulated in stomachs of stranded sperm whales. Overall, the species encompassed a narrow range in delta(13)C values (1.7 per thousand), indicating that they lived in closely related and overlapping habitats. delta(13)C values can be interpreted in terms of distribution with the more (13)C-depleted species (e.g. Stigmatoteuthis arcturi, Vampyroteuthis infernalis) having a more pelagic habitat than the more (13)C-enriched, bathyal species (e.g. Todarodes sagittatus and the giant squid Architeuthis dux). The cephalopods sampled had delta(15)N values ranging 4.6 per thousand, which is consistent with the species spanning approximately 1.5 trophic levels. Neither the giant octopod (Haliphron atlanticus) nor the giant squid reached the highest trophic position. Species delta(15)N was independent of body size, with large squids having both the highest (Taningia danae) and lowest (Lepidoteuthis grimaldii) delta(15)N values. Their trophic position indicates that some species share the top of the food web, together with other megacarnivores such as the sperm whale.

Natural abundances 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.

2010-01-01

A survey study was conducted on man-made plantations located at two different areas in the arid region of Syria to determine the variations in natural abundances of the 12 N and 13 C isotopes in leaves of several woody legume and non-legume species, and to better understand the consequence of such variations on nitrogen fixation and carbon assimilation. In the first study area (non-saline soil), the δ 15 N values in four legume species (Acacia cyanopylla, -1.73 %; Acacia farnesiana, -0.55%; Prosopis juliflora, -1.64%, and Medicago arborea, +1.6%) and one actinorhizal plant (Elaeagnus angustifolia, -0.46 to -2.1%) were found to be close to that of the atmospheric value pointing to a major contribution of N 2 fixing in these species; whereas, δ 15 N values of the non-fixing plant species were highly positive.δ 13 C% in leaves of the C 3 plants were found to be affected by plant species, ranging from a minimum of -28.67% to a maximum of -23%. However, they were relatively similar within each plant species although they were grown at different sites. In the second study area (salt affected soil) a higher carbon discrimination value (Δ 3 C%) was exhibited by Prosopis juliflora indicating that the latter is a salt tolerant species; however, its δ 15 N was highly positive (+7.03%) suggesting a negligible contribution of the fixed N 2 . Hence, it was concluded that the enhancement of N 2 fixation might be achieved by selection of salt-tolerant rhizobium strains. (author)

Changes in nitrogen isotopic compositions during composting of cattle feedlot manure: effects of bedding material type.

Science.gov (United States)

Kim, Young-Joo; Choi, Woo-Jung; Lim, Sang-Sun; Kwak, Jin-Hyeob; Chang, Scott X; Kim, Han-Yong; Yoon, Kwang-Sik; Ro, Hee-Myong

2008-09-01

Temporal changes in delta(15)N of cattle feedlot manure during its composting with either rice hull (RHM) or sawdust (SDM) as bedding materials were investigated. Regardless of the bedding material used, the delta(15)N of total N in the manure increased sharply from +7.6 per thousand to +9.9 per thousand and from +11.4 per thousand to +14.3 per thousand, respectively, in RHM or SDM, within 10 days from the commencement of composting. Such increases could be attributed primarily to N loss via NH(3) volatilization and denitrification based on the very high delta(15)N values (greater than +20 per thousand) of NH(4)(+) and NO(3)(-) in the co-composted manure. The delta(15)N of total N in RHM was substantially lower (by more than 3 per thousand) than that in SDM, suggesting that the delta(15)N of the composted manure was affected not only by N loss but also by the type of bedding material used. Specifically, the higher N concentration in the rice hull than in the saw dust could lead to a greater (15)N isotope dilution.

Hepatitis fulminante en la Sierra Nevada: Una forma de superinfección del virus delta con el virus de la hepatitis B.

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Alvaro Villanueva

1992-06-01

Full Text Available Durante septiembre de 1980 a octubre de 1983, se realizó un estudio seroepidemiológico para hepatitis A y B, en 258 personas en una ciudad (Santa Marta población de 250.000 y tres pequeños municipios (Santa Rosalía, Julio Zawady y Aracataca, poblaciones de 768, 800 y 5.000 habitantes respectivamente. La presencia de hepatitis A se encontró en un 77 a 93% (IgG Hepatitis A. Hbs Ag o Anti-Hbs Ag en 30.5% de la población en dos municipios (Santa Rosalía y Julio Zawady, en 2.5% en el municipio de Aracataca y 48.5% en la ciudad de Santa Marta. La presencia del Agente Delta (Anti-delta en el suero se determinó también en estas mismas poblaciones, encontrándose ausente en la ciudad y uno de los municipios (Aracataca, en contraste con una prevalencia de 13.7% y 22% en Julio Zawady y Santa Rosalía (P: 0.0001. Se excluyeron por historia clínica, antecedentes de drogadicción, transfusiones, o prácticas homosexuales, como mecanismos de transmisión de los virus B y delta. En veinte pacientes con diagnóstico histopalógico de hepatitis fulminante y en quienes se descartaron otras etiologías se demostró la presencia serológica de los virus de la hepatitis By Delta. De estos veinte, diez provenían de Julio Zawady y los otros diez de Santa Rosalía. La evolución clínica de esta enfermedad fue indistinguible de otras causas de falla hepática aguda. La mortalidad de estas formas fulminantes de hepatitis alcanzaron hasta un 65%. Los corticoides no modificaron el curso de esta enfermedad. La población joven mostró mayor compromiso y peor diagnóstico (P:0.033. La hepatitis fulminante de la Sierra Nevada de Santa Marta es el resultado de la superinfección con el virus Delta sobre la infección virus B. La aparición simultánea de casos intrafamiliares sugiere una relación importante entre los grupos comprometidos, aunque la forma exacta de transmisión permanece aún desconocida.

Stable isotopes, beaks and predators: a new tool to study the trophic ecology of cephalopods, including giant and colossal squids.

Science.gov (United States)

Cherel, Yves; Hobson, Keith A

2005-08-07

Cephalopods play a key role in the marine environment but knowledge of their feeding habits is limited by lack of data. Here, we have developed a new tool to investigate their feeding ecology by combining the use of their predators as biological samplers together with measurements of the stable isotopic signature of their beaks. Cephalopod beaks are chitinous hard structures that resist digestion and the stable isotope ratios of carbon (delta13C) and nitrogen (delta15N) are indicators of the foraging areas and trophic levels of consumers, respectively. First, a comparison of delta13C and delta15N values of different tissues from the same individuals showed that beaks were slightly enriched in 13C but highly impoverished in 15N compared with lipid-free muscle tissues. Second, beaks from the same species showed a progressive increase in their delta15N values with increasing size, which is in agreement with a dietary shift from lower to higher trophic levels during cephalopod growth. In the same way, there was an increase in the delta15N signature of various parts of the same lower beaks in the order rostrum, lateral walls and wings, which reflects the progressive growth and chitinization of the beaks in parallel with dietary changes. Third, we investigated the trophic structure of a cephalopod community for the first time. Values of delta15N indicate that cephalopods living in slope waters of the subantarctic Kerguelen Islands (n=18 species) encompass almost three distinct trophic levels, with a continuum of two levels between crustacean- and fish-eaters and a distinct higher trophic level occupied by the colossal squid Mesonychoteuthis hamiltoni. delta13C values demonstrated that cephalopods grow in three different marine ecosystems, with 16 species living and developing in Kerguelen waters and two species migrating from either Antarctica (Slosarczykovia circumantarctica) or the subtropics (the giant squid Architeuthis dux). The stable isotopic signature of beaks

sup 15 N-ammonium test in clinical research. Der ( sup 15 N)-Ammoniumtest in der klinischen Forschung

Energy Technology Data Exchange (ETDEWEB)

Jung, K; Metzner, C; Teichmann, B [Akademie der Wissenschaften der DDR, Leipzig (German Democratic Republic). Zentralinstitut fuer Isotopen- und Strahlenforschung Leipzig Univ. (German Democratic Republic). Bereich Medizin

1989-01-01

By use of the {sup 15}N-ammonium test the liver function is investigated under influence of hormonal contraceptives in women and in liver diseases in children. With the described noninvasive nonradioactive isotope test the ammonia detoxification capability and the urea synthesis capacity of the liver is determined by measuring of the {sup 15}N excretion in ammonia and urea in urine after oral administering of {sup 15}N-ammonium chloride. The {sup 15}N-ammonium test shows a significant influence of the hormonal contraceptives on the liver function and gives diagnostic evidence for liver diseases in children. (author).

Análisis autosimilar de pozos cuánticos cuasirregulares delta dopados tipo n en GaAs

Directory of Open Access Journals (Sweden)

Heraclio García-Cervantes

2014-01-01

Full Text Available Se estudia la esctructura electrónica de pozos cuánticos delta dopados tipo n en GaAs, en el cual el sistema de multiples pozos es construido de acuerdo a la secuencia de Fibonacci. Los bloques A y B corresponden a pozos delta dopados con una densidad de impurezas n2DA y n2DB, y el mismo ancho de los pozos. La aproximación de Thomas-Fermi, el modesemi-empírico de enlace fuerte (tight-binding sp3s* incluyendo el espín, el modelo de empalme de la función de Green y la matriz de transferencia fueron implementados para obtener el potencial de confinamiento, la estructura electrónica y la autosimilaridad del espectro. La fragmentación del espectro electrónico se presenta cada vez que los bloques A y B interaccionan, y aumenta a medida que la diferencia de impurezas entre A y B aumenta. La función de onda del primer estado de las bandas fragmentadas presenta características críticas, esto es, no es un estado localizado ni extendido, presenta características de autosimilaridad. Por lo tanto, las características cuasiregulares se conservan independientemente de la complejidad del sistema y pueden afectar el funcionamiento de los dispositivos basados a estas estructuras.

(p,. pi. /sup -/) reaction and. delta. /sup + +/ components of nuclei

Energy Technology Data Exchange (ETDEWEB)

Kisslinger, L S; Miller, G A [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics

1975-12-08

The use of the (p,..pi../sup -/) reaction as a probe to determine ..delta../sup + +/(1232) components of nuclear wave functions is examined within the framework of a model which treats baryon resonances on the same footing as nucleons. Nuclear structure properties which affect the ..delta..-probability are discussed. Estimates of cross sections, at several energies, are made for the ..delta../sup + +/ transfer contribution as well as for the competing processes: proton charge exchange (p,n) followed by an (n,..gamma../sup -/) reaction; emission of a ..pi../sup 0/ followed by pion charge exchange (..pi../sup -/,..pi../sup 0/). Even with ..delta..-probabilities as small as 0.0001 the ..delta..-transfer process can compete with ordinary background charge-exchange reactions.

Complete Measurement of Stable Isotopes in N2O (δ15N, δ15Nα, δ15Nβ, δ18O, δ17O) Using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS)

Science.gov (United States)

Leen, J. B.; Gupta, M.

2014-12-01

nitrate in soil and groundwater and may be used to differentiate other sources of nitrate for which the range of Δ17O values is much smaller. By measuring δ15N, δ15Nα, δ15Nβ, δ18O and δ17O, our instrument will help researchers unravel the complicated nitrate mixing problem to determine the sources and sinks of nitrate pollution.

Identifying sources of subsurface nitrate pollution with stable nitrogen isotopes. Final report, August 1976-March 1978

International Nuclear Information System (INIS)

Wolterink, T.J.; Williamson, H.J.; Jones, D.C.; Grimshaw, T.W.; Holland, W.F.

1979-08-01

This report describes the methods, results, conclusions, and recommendations of an investigation of a technique to identify sources of nitrate in ground water. A discussion of the theoretical basis of the technique is also provided. Over 300 soil and ground water samples were collected for this study. The samples are from numerous sites around the United States, representing a variety of environmental conditions. The nitrate in 66 of these samples was separated from other nitrogen species, converted to N2 gas, purified, and analyzed to determine the ratio (15)N/(14)N. These data were combined with the results of analyses performed previously by Jones (1) and Kreitler (2). Standard statistical techniques were used to analyze the observed variations in delta (15)N values, with respect to several nitrate sources and various environmental factors. It was found that nitrates from feedlots, barnyards and septic tanks can be distinguished from natural soil nitrates on the basis of their delta (15)N values. They cannot, however, be distinguished from each other. Environmental factors contributed to the observed variation in delta (15)N values

The ratio of deuterium to hydrogen in interstellar space. IV - The lines of sight to Delta, Epsilon, and Iota Orionis

Science.gov (United States)

Laurent, C.; Vidal-Madjar, A.; York, D. G.

1979-01-01

Deuterium absorption features in spectra of Delta, Epsilon, and Iota Ori obtained with Copernicus are analyzed. The Iota Ori line-of-sight analysis, which is quite detailed because of the high-velocity H I components superposed on the deuterium features, gives a D/H ratio (which is uncertain because of a complex profile) of 0.000014. A D/H ratio of the order of 7 millionths is determined for Delta and Epsilon Ori. For the complex line profiles involved, one may regard this as a formal lower limit. Several attempts were made to increase the ratio N(D I)/N(H I) in the context of reasonable models for the line of sight, but with no success; the derived values are therefore regarded as actual values, not lower limits. Since the derived value is an average on the line of sight, the possibility cannot be ruled out that the true ratios N(D I)/N(H I) in individual nearby components differ from the mean values. The mean value for these two directions is lower by a factor of 4 than the best value for the Zeta Pup line of sight (the highest yet derived for path lengths greater than 50 pc).

Shifts in Ross Sea food web structure as indicated by δ15N and δ13C values of fossil Antarctic seals

Science.gov (United States)

Leopold, A.; Brault, E.; McMahon, K.

2013-12-01

As climate change continues to mount, there is a growing need for understanding its effects on biological-physical interactions of marine ecosystems. Assessing the effects of anthropogenic activities on the coastal marine ecosystem involves understanding the underlying mechanisms driving these changes as well as establishing baselines of the natural system. Preliminary findings have indicated shifts in bulk carbon (C) and nitrogen (N) isotopic values of southern elephant seal (Mirounga leonina) samples, collected in the Dry Valleys of Antarctica in the Ross Sea region, over approximately the last 7,000 years. These shifts could result from 1) seals changing their foraging location and/or diet over this time, 2) climate change-induced shifts in the biogeochemistry at the base of the food web, or 3) some combination of both processes. We explored the patterns of long-term change in Ross Sea food web structure by examining the stable isotope values of three top predators in this system, Weddell seals (Leptonychotes weddellii), leopard seals (Hydrurga leptonyx), and crabeater seals (Lobodon carcinophagus). Fossil seal samples were collected in the Dry Valleys during the austral summer of 2012/13 and then analyzed for bulk C and N isotopes via an elemental analyzer/isotope-ratio mass spectrometer (EA/IRMS). Our initial findings indicate that C isotopic values of fossil seal samples from Weddell, leopard, and crabeater seals were more enriched than isotopic values of modern seals of the same species (e.g., δ13C = -22.79 × 0.92 ‰ and -26.71 × 0.50 ‰ for fossil and modern crabeater seals, respectively). Given the relatively consistent diet of crabeater seals, these findings suggest a shift in baseline food web structure occurred over the last 10,000 years, either through changes in foraging location or local shifts in biogeochemistry. For all species, N isotopic values are widely variable (e.g., 7.28 to 16.0 δ15N ‰ for the Weddell seal), which may be a result of

Impurity-related nonlinear optical properties in delta-doped quantum rings: Electric field effects

Energy Technology Data Exchange (ETDEWEB)

Restrepo, R.L., E-mail: rrestre@gmail.com [Escuela de Ingeniería de Antioquia-EIA, Medellín (Colombia); Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Morales, A.L. [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Martínez-Orozco, J.C. [Unidad Académica de Física, Universidad Autónoma de Zacatecas, CP 98060, Zacatecas (Mexico); Baghramyan, H.M.; Barseghyan, M.G. [Department of Solid State Physics, Yerevan State University, Al. Manookian 1, 0025 Yerevan (Armenia); Mora-Ramos, M.E. [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Ave. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Duque, C.A. [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia)

2014-11-15

Using a variational procedure within the effective mass approximation, we have calculated the donor impurity binding energy for the ground (1s-like) and the excited (2p{sub z}-like) states as well as the impurity-related nonlinear optical absorption and relative changes in the refraction index in a GaAs single quantum ring with axial n-type delta-doping. The delta-like potential along the z-direction is an approximate model analytically described using a Lorentzian function with two parameters. Additionally we consider the application of an electric field along the z-direction. It is found that the changes in the geometry of the quantum ring, the change in the 2D impurity density of the delta-like doping, and different values of the electric field lead to a shifting of the resonant peaks of the optical responses spectrum.

Impurity-related nonlinear optical properties in delta-doped quantum rings: Electric field effects

International Nuclear Information System (INIS)

Restrepo, R.L.; Morales, A.L.; Martínez-Orozco, J.C.; Baghramyan, H.M.; Barseghyan, M.G.; Mora-Ramos, M.E.; Duque, C.A.

2014-01-01

Using a variational procedure within the effective mass approximation, we have calculated the donor impurity binding energy for the ground (1s-like) and the excited (2p z -like) states as well as the impurity-related nonlinear optical absorption and relative changes in the refraction index in a GaAs single quantum ring with axial n-type delta-doping. The delta-like potential along the z-direction is an approximate model analytically described using a Lorentzian function with two parameters. Additionally we consider the application of an electric field along the z-direction. It is found that the changes in the geometry of the quantum ring, the change in the 2D impurity density of the delta-like doping, and different values of the electric field lead to a shifting of the resonant peaks of the optical responses spectrum

LBA-ECO CD-02 C and N Isotopes in Leaves and Atmospheric CO2, Amazonas, Brazil

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set reports delta 13C/12C results for leaf tissues and atmospheric carbon dioxide (CO2), delta 15N/14N ratios for leaf tissue, and leaf carbon...

Resonances in the nuclear reactions 15N + 12C and 15N + 16O

International Nuclear Information System (INIS)

Monnehan, G.A.

1987-06-01

The reaction 12 C + 15 N have been studied at 15 N beam energies between 30 and 70 MeV. For each reaction, about twelve residual nuclei have been identified through the γ-ray detection method. Excitation functions were obtained for the fusion and peripheral channels. Resonances are seen in the channels containing at least one α particle at energies below 50 MeV. At higher energies, strong structures are observed in the direct reaction channels. The evolution of the fusion cross section is well reproduced by a model based on the statistical desexcitation of the compound nucleus if the discrete states of the residual nuclei are taken into account. The favourable observation of resonant phenomena in 15 N induced reactions can be understood in terms of a small number of channels open to the grazing wave. In the range 50 to 60 MeV, there is a strong coupling between the fusion and the direct reaction channels. The occurrence of resonances above E lab = 50 MeV in the peripheral channels is explained with the band crossing and effective barrier models. In the 15 N induced reactions, the absorption of the surface waves is weak [fr

Stable Isotope (delta OXYGEN-18, Delta Deuterium, Delta CARBON-13) Dendroclimatological Studies in the Waterloo Region of Southern Ontario, Canada, Between AD 1610 and 1990.

Science.gov (United States)

Buhay, William Mark

Oxygen (delta^{18} O), hydrogen (delta^2H) and carbon (delta^{13}C) isotopes were measured in wood cellulose from elm, white pine and maple trees that grew in southwestern Ontario, Canada. The measured oxygen and hydrogen isotopic data were used for model-based reconstructions of delta^{18}{O}_{meteoric water}, mean annual temperature (MAT) and relative humidity for a period, AD 1610 to 1880, that precedes instrumental records of climate. The carbon isotope measurements were compared with the Cellulose Model inferred climate data to reveal additional environmental information. Modifications made to the Cellulose Model focused on the dynamics of oxygen and hydrogen isotopic fractionation in plants during evapotranspiration and photosynthetic assimilation. For instance, kinetic fractionation of ^{18}O was found to be predictable from theoretical considerations of leaf energy balance and boundary layer dynamics. Kinetic fractionation during evapotranspiration is sensitive to the nature of the boundary layer, which is controlled by leaf size and morphology. Generally, plants with small segmented leaves have a lower component of turbidity in the leaf boundary layer, which results in higher kinetic fractionation values, than do plants having large simple leaves and more turbulent boundary layers. Kinetic ^2H enrichment in plant leaf water can also be rationalized in terms of leaf size and morphology when an apparent temperature-dependent isotope effect, acting in opposition to evaporative enrichment, is taken into account. Accounting for this temperature -dependent isotope effect helps to: (1) reconcile hydrogen kinetic fractionation inconsistencies for different leaves; (2) explain a temperature effect previously attributed to variable biochemical fractionation during cellulose synthesis, and; (3) verify hydrogen biochemical effects in plants. This improved characterization of the oxygen and hydrogen isotopic effects in plants, using the modified Cellulose Model, helped

Spin-polarized electron tunneling across a Si delta-doped GaMnAs/n-GaAs interface

DEFF Research Database (Denmark)

Andresen, S.E.; Sørensen, B.S.; Lindelof, P.E.

2003-01-01

Spin-polarized electron coupling across a Si delta-doped GaMnAs/n-GaAs interface was investigated. The injection of spin-polarized electrons was detected as circular polarized emission from a GaInAs/GaAs quantum well light emitting diode. The angular momentum selection rules were simplified...

Average of delta: a new quality control tool for clinical laboratories.

Science.gov (United States)

Jones, Graham R D

2016-01-01

Average of normals is a tool used to control assay performance using the average of a series of results from patients' samples. Delta checking is a process of identifying errors in individual patient results by reviewing the difference from previous results of the same patient. This paper introduces a novel alternate approach, average of delta, which combines these concepts to use the average of a number of sequential delta values to identify changes in assay performance. Models for average of delta and average of normals were developed in a spreadsheet application. The model assessed the expected scatter of average of delta and average of normals functions and the effect of assay bias for different values of analytical imprecision and within- and between-subject biological variation and the number of samples included in the calculations. The final assessment was the number of patients' samples required to identify an added bias with 90% certainty. The model demonstrated that with larger numbers of delta values, the average of delta function was tighter (lower coefficient of variation). The optimal number of samples for bias detection with average of delta was likely to be between 5 and 20 for most settings and that average of delta outperformed average of normals when the within-subject biological variation was small relative to the between-subject variation. Average of delta provides a possible additional assay quality control tool which theoretical modelling predicts may be more valuable than average of normals for analytes where the group biological variation is wide compared with within-subject variation and where there is a high rate of repeat testing in the laboratory patient population. © The Author(s) 2015.

LBA-ECO CD-02 C and N Isotopes in Leaves and Atmospheric CO2, Amazonas, Brazil

Data.gov (United States)

National Aeronautics and Space Administration — This data set reports delta 13C/12C results for leaf tissues and atmospheric carbon dioxide (CO2), delta 15N/14N ratios for leaf tissue, and leaf carbon and nitrogen...

Synthesis of fertilizers nitrogen and 15N-enriched. Pt. I. Production of enriched 15N-anhydrous ammonia

International Nuclear Information System (INIS)

Bendassolli, J.A.; Mortatti, J.; Trivelin, P.C.O.; Victoria, R.L.

1988-01-01

The results of 15 N-anhydrous ammonia production through reaction between 15 N-enriched ammonium sulphate and sodium hidroxide are reported. Influence of the reaction temperature, carrier gas flow, reaction time and mass of ammonium sulphate on the production of anhydrous ammonia were studied. Analyses for the cost of production of 5% atoms in 15 N-enriched anhydrous ammonia were made. (M.A.C.) [pt

Resolution of the 15N balance enigma?

International Nuclear Information System (INIS)

Clough, T.J.; Sherlock, R.R.; Cameron, K.C.; Stevens, R.J.; Laughlin, R.J.; Mueller, C.

2001-01-01

The enigma of soil nitrogen balance sheets has been discussed for over 40 years. Many reasons have been considered for the incomplete recovery of 15 N applied to soils, including sampling uncertainty, gaseous N losses from plants, and entrapment of soil gases. The entrapment of soil gases has been well documented for rice paddy and marshy soils but little or no work appears to have been done to determine entrapment in drained pasture soils. In this study 15 N-labelled nitrate was applied to a soil core in a gas-tight glovebox. Water was applied, inducing drainage, which was immediately collected. Dinitrogen and N -2 were determined in the flux through the soil surface, and in the gases released into the glovebox as a result of irrigation or physical destruction of the core. Other components of the N balance were also measured, including soil inorganic-N and organic-N. Quantitative recovery of the applied 15 N was achieved when the experiment was terminated 484 h after the 15 N-labelled material was applied. Nearly 23% of the 15 N was recovered in the glovebox atmosphere as N 2 and N 2 O due to diffusion from the base of the soil core, convective flow after irrigation, and destructive soil sampling. This 15 N would normally be unaccounted for using the sampling methodology typically employed in 15 N recovery experiments. Copyright (2001) CSIRO Publishing

Mangrove isotopic (δ15N and δ13C) fractionation across a nitrogen vs. phosphorus limitation gradient

Science.gov (United States)

Mckee, Karen L.; Feller, Ilka C.; Popp, Marianne; Wanek, Wolfgang

2002-01-01

Mangrove islands in Belize are characterized by a unique switching from nitrogen (N) to phosphorus (P) limitation to tree growth from shoreline to interior. Fertilization has previously shown that Rhizophora mangle (red mangrove) fringe trees (5–6 m tall) growing along the shoreline are N limited; dwarf trees (!1.5 m tall) in the forestinterior are P limited; and transition trees (2–4 m tall) are co-limited by both N and P.  Growth patterns paralleled a landward decrease in soil flushing by tides and an increase in bioavailable N, but P availability remained consistently low across the gradient. Stable isotopic composition was measured in R. mangle leaves to aid in explaining this nutrient switching pattern and growth variation. Along control transects, leaf !15N decreased from "0.10‰ (fringe) to #5.38‰ (dwarf). The !15N of N-fertilized trees also varied spatially, but the values were consistently more negative (by $3‰) compared to control trees. Spatial variation in !15N values disappeared when the trees were fertilized with P, and values averaged "0.12‰, similar to that in control fringe trees. Neither variation in source inputs nor microbial fractionation could fully account for the observed patterns in !15N. The results instead suggest that the lower !15N values in transition and dwarf control trees were due to plant fractionation as a consequence of slower growth and lower N demand. P fertilization increased N demand and decreased fractionation. Although leaf !13C was unaffected by fertilization, values increased from fringe (#28.6‰) to transition (#27.9‰) to dwarf (#26.4‰) zones, indicating spatial variation in environmental stresses affecting stomatal conductance or carboxylation. The results thus suggest an interaction of external supply, internal demand, and plant ability to acquire nutrients under different hydro-edaphic conditions that vary across this tree-height gradient. The findings not only aid in understanding

N-15 analysis by emission spectroscopy

Energy Technology Data Exchange (ETDEWEB)

NONE

1983-12-31

The stable isotope of nitrogen, N-15, has become widely used as tracer in agriculture, medicine and biology research. The film gives an overview of the sample preparation and analytical procedures followed in the analysis of the nitrogen isotopic composition (14N/15N ratio) by optical emission spectrometry at the Seibersdorf Laboratory. The subsampling of plant material and the several steps of chemical pretreatment such as Kjeldahl digestion, distillation, titration and adjustment of the proper N concentration in the extract are demonstrated. The preparation of the discharge tubes is shown in detail. Final measurement of the 14N/15N ratio is carried out with the NOI-5 and JASCO emission spectrometers

Emission spectroscopic 15N analysis 1985

International Nuclear Information System (INIS)

Meier, G.

1986-01-01

The state of the art of emission spectroscopic 15 N analysis is demonstrated taking the NOI-6e 15 N analyzer as an example. The analyzer is equipped with a microcomputer to ensure a high operational comfort, computer control, and both data acquisition and data processing. In small amounts of nitrogen-containing substances (10 to 50 μg N 2 ) the 15 N abundance can be very quickly determined in standard discharge tubes or in aqueous ammonium salt solutions with a standard deviation less than 0.6 percent

Retrospective characterization of ontogenetic shifts in killer whale diets via δ13C and δ15N analysis of teeth

Science.gov (United States)

Newsome, Seth D.; Etnier, Michael A.; Monson, Daniel H.; Fogel, Marilyn L.

2009-01-01

Metabolically inert, accretionary structures such as the dentin growth layers in teeth provide a life history record of individual diet with near-annual resolution. We constructed ontogenetic δ13C and δ15N profiles by analyzing tooth dentin growth layers from 13 individual killer whales Orcinus orca collected in the eastern northeast Pacific Ocean between 1961 and 2003. The individuals sampled were 6 to 52 yr old, representing 2 ecotypes—resident and transient—collected across ~25° of latitude. The average isotopic values of transient individuals (n = 10) are consistent with a reliance on mammalian prey, while the average isotopic values of residents (n = 3) are consistent with piscivory. Regardless of ecotype, most individuals show a decrease in δ15N values of ~2.5‰ through the first 3 yr of life, roughly equivalent to a decrease of one trophic level. We interpret this as evidence of gradual weaning, after which, ontogenetic shifts in isotopic values are highly variable. A few individuals (n = 2) maintained relatively stable δ15N and δ13C values throughout the remainder of their lives, whereas δ15N values of most (n = 11) increased by ~1.5‰, suggestive of an ontogenetic increase in trophic level. Significant differences in mean δ13C and δ15N values among transients collected off California suggest that individuality in prey preferences may be prevalent within this ecotype. Our approach provides retrospective individual life history and dietary information that cannot be obtained through traditional field observations of free-ranging and elusive species such as killer whales, including unique historic ecological information that pre-dates modern studies. By providing insights into individual diet composition, stable isotope analysis of teeth and/or bones may be the only means of evaluating a number of hypothesized historical dietary shifts in killer whales of the northeast Pacific Ocean

Light Cone Sum Rules for gamma*N ->Delta Transition Form Factors

Energy Technology Data Exchange (ETDEWEB)

V.M. Braun; A. Lenz; G. Peters; A. Radyushkin

2006-02-01

A theoretical framework is suggested for the calculation of {gamma}* N {yields} {Delta} transition form factors using the light-cone sum rule approach. Leading-order sum rules are derived and compared with the existing experimental data. We find that the transition form factors in a several GeV region are dominated by the ''soft'' contributions that can be thought of as overlap integrals of the valence components of the hadron wave functions. The ''minus'' components of the quark fields contribute significantly to the result, which can be reinterpreted as large contributions of the quark orbital angular momentum.

Plot-size for 15N-fertilizer recovery studies by tanzania-grass

International Nuclear Information System (INIS)

Martha Junior, Geraldo Bueno; Trivelin, Paulo Cesar Ocheuze; Corsi, Moacyr

2009-01-01

The understanding of the N dynamics in pasture ecosystems can be improved by studies using the 15 N tracer technique. However, in these experiments it must be ensured that the lateral movement of the labeled fertilizer does not interfere with the results. In this study the plot-size requirements for 15 N-fertilizer recovery experiments with irrigated Panicum maximum cv. Tanzania was determined. Three grazing intensities (light, moderate and intensive grazing) in the winter, spring and summer seasons were considered. A 1 m 2 plot-size, with a grass tussock in the center, was adequate, irrespective of the grazing intensity or season of the year. Increasing the distance from the area fertilized with 15 N negatively affected the N derived from fertilizer (Npfm) recovered in herbage.The lowest decline in Npfm values were observed for moderate and light grazing intensities. This fact might be explained by the vigorous growth characteristics of these plants. Increasing the grazing intensity decreased the tussock mass and, the smaller the tussock mass, the greater was the dependence on fertilizer nitrogen. (author)

Light-mediated 15N fractionation in Caribbean gorgonian octocorals: implications for pollution monitoring

Science.gov (United States)

Baker, D. M.; Kim, K.; Andras, J. P.; Sparks, J. P.

2011-09-01

The stable nitrogen isotope ratio ( δ 15N) of coral tissue is a useful recorder of anthropogenic pollution in tropical marine ecosystems. However, little is known of the natural environmentally induced fractionations that affect our interpretation of coral δ 15N values. In symbiotic scleractinians, light affects metabolic fractionation of N during photosynthesis, which may confound the identification of N pollution between sites of varied depth or turbidity. Given the superiority of octocorals for δ 15N studies, our goal was to quantify the effect of light on gorgonian δ 15N in the context of monitoring N pollution sources. Using field collections, we show that δ 15N declined by 1.4‰ over 20 m depth in two species of gorgonians, the common sea fan, Gorgonia ventalina, and the slimy sea plume, Pseudopterogorgia americana. An 8-week laboratory experiment with P. americana showed that light, not temperature causes this variation, whereby the lowest fractionation of the N source was observed in the highest light treatment. Finally, we used a yearlong reciprocal depth transplant experiment to quantify the time frame over which δ 15N changes in G. ventalina as a function of light regime . Over the year, δ 15N was unchanged and increased slightly in the deep control colonies and shallow colonies transplanted to the deep site, respectively. Within 6 months, colonies transplanted from deep to shallow became enriched by 0.8‰, mirroring the enrichment observed in the shallow controls, which was likely due to the combined effect of an increase in the source δ 15N and reduced fractionation. We conclude that light affects gorgonian δ 15N fractionation and should be considered in sampling designs for N pollution monitoring. However, these fractionations are small relative to differences observed between natural and anthropogenic N sources.

Plot-size for {sup 15}N-fertilizer recovery studies by tanzania-grass; Tamanho da parcela para estudos de recuperacao de fertilizante-{sup 15}N por capim-tanzania

Energy Technology Data Exchange (ETDEWEB)

Martha Junior, Geraldo Bueno [EMBRAPA Cerrados, Planaltina, DF (Brazil)], e-mail: gbmartha@cpac.embrapa.br; Trivelin, Paulo Cesar Ocheuze [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis], e-mail: pcotrive@cena.usp.br; Corsi, Moacyr [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Zootecnia], e-mail: moa@esalq.usp.br

2009-07-01

The understanding of the N dynamics in pasture ecosystems can be improved by studies using the {sup 15}N tracer technique. However, in these experiments it must be ensured that the lateral movement of the labeled fertilizer does not interfere with the results. In this study the plot-size requirements for {sup 15}N-fertilizer recovery experiments with irrigated Panicum maximum cv. Tanzania was determined. Three grazing intensities (light, moderate and intensive grazing) in the winter, spring and summer seasons were considered. A 1 m{sup 2} plot-size, with a grass tussock in the center, was adequate, irrespective of the grazing intensity or season of the year. Increasing the distance from the area fertilized with {sup 15}N negatively affected the N derived from fertilizer (Npfm) recovered in herbage.The lowest decline in Npfm values were observed for moderate and light grazing intensities. This fact might be explained by the vigorous growth characteristics of these plants. Increasing the grazing intensity decreased the tussock mass and, the smaller the tussock mass, the greater was the dependence on fertilizer nitrogen. (author)

A novel antipyretic action of 15-deoxy-Delta12,14-prostaglandin J2 in the rat brain.

Science.gov (United States)

Mouihate, Abdeslam; Boissé, Lysa; Pittman, Quentin J

2004-02-11

Fever is an important part of the host defense response, yet fever can be detrimental if it is uncontrolled. We provide the first evidence that 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2), an endogenous ligand for peroxisome proliferator-activated receptor gamma (PPARgamma), can attenuate the febrile response to lipopolysaccharide (LPS) in rats via an action on the brain. Furthermore, we show that PPARgamma is expressed in the hypothalamus, an important locus in the brain for fever generation. In addition, 15d-PGJ2 and its synthesizing enzyme (PGD2 synthase) were present in rat cerebrospinal fluid, and their levels were enhanced in response to systemic injection of LPS. The antipyretic effect of 15d-PGJ2 was associated with reduction in LPS-stimulated cyclooxygenase-2 expression in the hypothalamus but not in p44/p42 mitogen-activated protein kinase phosphorylation or in the expression of the PPARgamma. Thus it is likely that there is a parallel induction of an endogenous prostanoid pathway in the brain capable of limiting deleterious actions of the proinflammatory prostaglandin E2-dependent pathway.

Distribution of spin dipole transition strength in the 15N(n,p)15C reaction

International Nuclear Information System (INIS)

Cellar, A.; Alford, W.P.; Helmer, R.; Abegg, R.; Frekers, D.; Haeusser, O.; Henderson, R.S.; Jackson, K.P.; Vetterli, M.; Yen, S.; Jeppesen, R.; Larson, B.; Mildenberger, J.; Pointon, B.W.; Trudel, A.

1990-08-01

The reaction 15 N(n,p) 15 C was studied at a neutron energy of 288 MeV using the TRIUMF (n,p) charge exchange facility and a high pressure gas target. The angular distributions for spin dipole (ΔL=1) transitions to the states in 15 C at energies 0 MeV and 0.740 MeV, as well as for higher excitation energies, were measured and the results were compared with DWIA calculations. The measured distribution of the spin dipole strength agrees well with shell model predictions, indicating that a rather simple model provides a satisfactory description of the 15 N ground state, and of positive parity states in 15 C up to about 18 MeV excitation. The magnitude of the peak cross sections (at ≅ 7 degrees) is described well by the calculations when the theoretical cross section is renormalized by a factor 0.7. The calculated cross sections near zero degrees are generally smaller than experimental data. It this is a general feature of ΔL=1 transitions, it suggests that estimates of GT strength based on a multipole decomposition of measured cross sections may be too high. (Author) (41 refs., 3 tabs., 14 figs.)

Fast hydrogen exchange affects 15N relaxation measurements in intrinsically disordered proteins

International Nuclear Information System (INIS)

Kim, Seho; Wu, Kuen-Phon; Baum, Jean

2013-01-01

Unprotected amide protons can undergo fast hydrogen exchange (HX) with protons from the solvent. Generally, NMR experiments using the out-and-back coherence transfer with amide proton detection are affected by fast HX and result in reduced signal intensity. When one of these experiments, 1 H– 15 N HSQC, is used to measure the 15 N transverse relaxation rate (R 2 ), the measured R 2 rate is convoluted with the HX rate (k HX ) and has higher apparent R 2 values. Since the 15 N R 2 measurement is important for analyzing protein backbone dynamics, the HX effect on the R 2 measurement is investigated and described here by multi-exponential signal decay. We demonstrate these effects by performing 15 N R 2 CPMG experiments on α-synuclein, an intrinsically disordered protein, in which the amide protons are exposed to solvent. We show that the HX effect on R 2 CPMG can be extracted by the derived equation. In conclusion, the HX effect may be pulse sequence specific and results from various sources including the J coupling evolution, the change of steady state water proton magnetization, and the D 2 O content in the sample. To avoid the HX effect on the analysis of relaxation data of unprotected amides, it is suggested that NMR experimental conditions insensitive to the HX should be considered or that intrinsic R 2 CPMG values be obtained by methods described herein.

Cyanobacteria-derived nitrogen uptake by benthic invertebrates in Lake Taihu: a mesocosm study using 15N labeling

Directory of Open Access Journals (Sweden)

Yu J.

2014-01-01

Full Text Available Eutrophication of lakes can lead to dominance by cyanobacteria, which are hardly used by zooplankton due to their low nutrition value. However, sedimented cyanobacterial detritus may be a useful source for benthic invertebrates. We studied the Microcystis-derived nitrogen incorporation in benthic invertebrates in Lake Taihu using stable isotopic nitrogen (15N as a tracer. The δ15N of all organisms increased significantly with time after addition of the labeled Microcystis detritus. δ15N values of POM and periphyton peaked earlier than for benthic invertebrates, and the maximum levels were also higher than bivalves, snails and worms (Limnodrilus spp.. Among benthic invertebrates, Radix swinhoei peaked later than other invertebrates, but the maximum level and the excess 15N of the last sampling day were higher. At the end of the experiment, approximately 70% of the added 15N was retained in the benthic food web, while only a small fraction (less than 1% of the added detritus 15N occurred in the pelagic food web. Our results suggest that nitrogen from cyanobacteria can be incorporated more in benthic than pelagic food webs and cyanobacterial blooms may contribute to the development of benthic animals.

Coral skeletal δ15N reveals isotopic traces of an agricultural revolution

International Nuclear Information System (INIS)

Marion, Guy S.; Dunbar, Robert B.; Mucciarone, David A.; Kremer, James N.; Lansing, J. Stephen; Arthawiguna, Alit

2005-01-01

This study introduces a new method of tracing the history of nutrient loading in coastal oceans via δ 15 N analysis of organic nitrogen preserved in the skeleton of the massive Porites coral. Four coral cores were collected in Bali, Indonesia, from reefs exposed to high levels of fertilizers in agricultural run-off, from lagoonal corals impacted by sewage, and from a reef located 30 km offshore. Skeletal δ 15 N in the agriculturally exposed coral declined from 10.7 ± 0.4 per mille in 1970-1971, when synthetic fertilizers (-0.8 per mille ± 0.2 per mille ) were introduced to Bali, to a depleted 'anthropogenic' baseline of 3.5 per mille ± 0.4% in the mid-1990s. δ 15 N values were negatively correlated with rainfall, suggesting that marine δ 15 N lowers during flood-born influxes of waste fertilizers. Reef cores exposed to untreated sewage in terrestrial discharge were enriched (7.8 and 7.3 ± 0.4 per mille ), while the offshore core reflected background oceanic signals (6.2 ± 0.4 per mille). δ 15 N, N concentration, and C:N systematics indicate that the N isotopic composition of skeletal organic matter was generally well preserved over 30 years. We suggest that skeletal organic δ 15 N can serve as a recorder of past nitrogen sources. In Bali, this tracer suggests that the intensification of Western style agricultural practices since 1970 are contributing to the degradation of coastal coral reefs

Solid-Liquid equilibrium of n-alkanes using the Chain Delta Lattice Parameter model

DEFF Research Database (Denmark)

Coutinho, João A.P.; Andersen, Simon Ivar; Stenby, Erling Halfdan

1996-01-01

The formation of a solid phase in liquid mixtures with large paraffinic molecules is a phenomenon of interest in the petroleum, pharmaceutical, and biotechnological industries among onters. Efforts to model the solid-liquid equilibrium in these systems have been mainly empirical and with different...... degrees of success.An attempt to describe the equilibrium between the high temperature form of a paraffinic solid solution, commonly known as rotator phase, and the liquid phase is performed. The Chain Delta Lattice Parameter model (CDLP) is developed allowing a successful description of the solid-liquid...... equilibrium of n-alkanes ranging from n-C_20 to n-C_40.The model is further modified to achieve a more correct temperature dependence because it severely underestimates the excess enthalpy. It is shown that the ratio of excess enthalpy and entropy for n-alkane solid solutions, as happens for other solid...

Search for correlatable, isotopically light carbon and nitrogen components in Lunar soils and breccias

International Nuclear Information System (INIS)

Norris, S.J.; Swart, P.K.; Wright, I.P.; Grady, M.M.; Pillinger, C.T.

1983-01-01

Using stepped heating extraction techniques, determinations of carbon and nitrogen content and delta 13 C and delta 15 N values have been obtained for selected lunar soils and breccias. Only nitrogen data have been gathered for representative splits separated by size, density and magnetic properties from 12023. A plot of the total delta 13 C (after terrestrial contamination is removed) versus delta 15 N values for the bulk samples reveals little evidence for a correlation between isotopically light carbon and isotopically light nitrogen of putative ancient solar wind origin. Soil 12023 is used to examine the current interpretation for the stepped release profile of nitrogen from bulk lunar samples. Mature agglutinates, postulated by previous workers to be the host of the light nitrogen, are shown to have a very constant delta 15 N value which is heavy rather than light. The actual host of the light nitrogen in 12023 has not been identified. The lowest values encountered during the study were found associated with the finest soil, but none of these was as low as for some temperature steps of the bulk soil. Interpretations regarding the origin of light nitrogen, if it is not present in agglutinates, await the results of more definitive efforts to identify the host phase

Synthesis of hydroxylamine-15 N.HCl

International Nuclear Information System (INIS)

Baldea, Aurel

2001-01-01

15 N labelled hydroxylamine is one of the starting substance for synthesis of labelled oximes. Industrial procedure was chosen to prepare hydroxylamine- 15 N. Sodium nitrite reduced by sodium bisulfite and sulfur dioxide, at temperature of 0-2 deg. C, produces sodium hydroxylamine disulfonate. The reaction mixture is treated with acetone and the resulting acetoxime is distilled. In order to obtain crystalline hydroxylamine hydrochloride, hydrochloric acid is added to the distillate and the solution is evaporated to dryness. The crude product was purified by recristallization, yielding 62-65% of theoretical amount. Labelled ammonium chloride formed as byproduct can be recovered improving 15 N balance. IR spectra is used for chemical analysis and mass spectrometry for isotopic analysis. For this purpose hydroxylamine- 15 N is converted into molecular nitrogen. (author)

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide

Energy Technology Data Exchange (ETDEWEB)

Domanska, Urszula [Physical Chemistry Department, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)], E-mail: ula@ch.pw.edu.pl; Marciniak, Andrzej [Physical Chemistry Department, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

2009-12-15

The activity coefficients at infinite dilution, {gamma}{sub 13}{sup {infinity}} for 36 solutes: alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, ethers, acetone, and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide [bmPY][NTf{sub 2}] were determined by gas-liquid chromatography at temperatures from 298.15 K to 368.15 K. The partial molar excess enthalpies at infinite dilution values {delta}H{sub 1}{sup E,{infinity}} were calculated from the experimental {gamma}{sub 13}{sup {infinity}} values obtained over the temperature range. The selectivity for different separation problems were calculated from the {gamma}{sub 13}{sup {infinity}} and compared to the literature values for other ionic liquids, N-methyl-2-pyrrolidinone (NMP) and sulfolane.

Mazda kiintotyövaiheiden perustaminen : Delta Auto Oy

OpenAIRE

Schreck, Ville

2012-01-01

Täyden palvelun autoliikeketju Delta Auto myy ja huoltaa Kia-, Mitsubishi- ja Mazda-merkkisiä autoja paikkakuntakohtaisesti kahdessakymmenessäviidessä toimipisteessä. Opinnäytetyön tarkoituksena oli tehdä toimiva ratkaisu Mazdan työvaiheiden sekä työpakettien myyntiin Automaster-ohjelmistoon. Työvaiheet sekä ohjeajat tulevat käyttöön kaikkiin Delta Auton toimipisteisiin ympäri Suomea. Työn lähdemateriaalin sain Inchcape Motor Finland Oy:ltä, joka toimii Suomessa Mazdan maahantuojana. Tarve tä...

15C-15F Charge Symmetry and the 14C(n,γ)15C Reaction Puzzle

International Nuclear Information System (INIS)

Timofeyuk, N.K.; Thompson, I.J.; Baye, D.; Descouvemont, P.; Kamouni, R.

2006-01-01

The low-energy reaction 14 C(n,γ) 15 C provides a rare opportunity to test indirect methods for the determination of neutron capture cross sections by radioactive isotopes versus direct measurements. It is also important for various astrophysical scenarios. Currently, puzzling disagreements exist between the 14 C(n,γ) 15 C cross sections measured directly, determined indirectly, and calculated theoretically. To solve this puzzle, we offer a strong test based on a novel idea that the amplitudes for the virtual 15 C→ 14 C+n and the real 15 F→ 14 O+p decays are related. Our study of this relation, performed in a microscopic model, shows that existing direct and some indirect measurements strongly contradict charge symmetry in the 15 C and 15 F mirror pair. This brings into question the experimental determinations of the astrophysically important (n,γ) cross sections for short-lived radioactive targets

Controls of {delta}{sup 34}S and {delta}{sup 18}O in dissolved sulphate: Learning from a detailed survey in the Llobregat River (Spain)

Energy Technology Data Exchange (ETDEWEB)

Otero, Neus [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain); Grup d' Hidrogeoquimica, Departament de Geologia Ambiental, Institut de Ciencies de la Terra ' Jaume Almera' , CSIC, Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain)], E-mail: notero@ub.edu; Soler, Albert; Canals, Angels [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain)

2008-05-15

The S and O isotopic composition of dissolved SO{sub 4}, used as a tracer for SO{sub 4} sources, was applied to the water of the Llobregat River system (NE Spain). The survey was carried out at 30 sites where surface water was sampled on a monthly basis over a period of 2a. The concentration of dissolved SO{sub 4} varied from 20 to 1575 mg L{sup -1}. Sulphur isotopic compositions clustered in two populations: one - 93% of the samples - had positive values with a mode of +9 per mille ; the other had negative values and a mode of -5 per mille . Data for {delta}{sup 18}O{sub SO{sub 4}} showed a mean value of +11 per mille , with no bi-modal distribution, though lower values of {delta}{sup 18}O corresponded to samples with negative {delta}{sup 34}S. These values can not be explained solely by the contribution of bedrock SO{sub 4} sources: that is, sulphide oxidation and the weathering of outcrops of sulphates, though numerous chemical sediments exist in the basin. Even in a river with a high concentration of natural sources of dissolved SO{sub 4}, such as the Llobregat River, the {delta}{sup 34}S values suggest that dissolved SO{sub 4} is controlled by a complex mix of both natural and anthropogenic sources. The main anthropogenic sources in this basin are fertilizers, sewage, potash mine effluent and power plant emissions. Detailed river water sampling, together with the chemical and isotopic characterisation of the main anthropogenic inputs, allowed determination of the influence of redox processes, as well as identification of the contribution of natural and anthropogenic SO{sub 4} sources and detection of spatial variations and seasonal changes among these sources. For instance, in the Llobregat River the input of fertilisers is well marked seasonally. Minimum values of {delta}{sup 34}S are reported during fertilization periods - from January to March - indicating a higher contribution of this source. The dual isotope approach, {delta}{sup 34}S and {delta}{sup 18}O

FIRST MEASUREMENTS OF {sup 15}N FRACTIONATION IN N{sub 2}H{sup +} TOWARD HIGH-MASS STAR-FORMING CORES

Energy Technology Data Exchange (ETDEWEB)

Fontani, F. [INAF-Osservatorio Astrofisico di Arcetri, L.go E. Fermi 5, I-50125 Firenze (Italy); Caselli, P.; Bizzocchi, L. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse 1, D-85748 Garching (Germany); Palau, A. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, P.O. Box 3-72, 58090 Morelia, Michoacán, México (Mexico); Ceccarelli, C. [Univ. Grenoble Alpes, IPAG, F-38000 Grenoble (France)

2015-08-01

We report on the first measurements of the isotopic ratio {sup 14}N/{sup 15}N in N{sub 2}H{sup +} toward a statistically significant sample of high-mass star-forming cores. The sources belong to the three main evolutionary categories of the high-mass star formation process: high-mass starless cores, high-mass protostellar objects, and ultracompact H ii regions. Simultaneous measurements of the {sup 14}N/{sup 15}N ratio in CN have been made. The {sup 14}N/{sup 15}N ratios derived from N{sub 2}H{sup +} show a large spread (from ∼180 up to ∼1300), while those derived from CN are in between the value measured in the terrestrial atmosphere (∼270) and that of the proto-solar nebula (∼440) for the large majority of the sources within the errors. However, this different spread might be due to the fact that the sources detected in the N{sub 2}H{sup +} isotopologues are more than those detected in the CN ones. The {sup 14}N/{sup 15}N ratio does not change significantly with the source evolutionary stage, which indicates that time seems to be irrelevant for the fractionation of nitrogen. We also find a possible anticorrelation between the {sup 14}N/{sup 15}N (as derived from N{sub 2}H{sup +}) and the H/D isotopic ratios. This suggests that {sup 15}N enrichment could not be linked to the parameters that cause D enrichment, in agreement with the prediction by recent chemical models. These models, however, are not able to reproduce the observed large spread in {sup 14}N/{sup 15}N, pointing out that some important routes of nitrogen fractionation could be still missing in the models.

Nitrogen dynamics in stream wood samples incubated with [14C]lignocellulose and potassium[15N]nitrate

International Nuclear Information System (INIS)

Aumen, N.G.; Bottomley, P.J.; Gregory, S.V.

1985-01-01

Surface wood samples obtained from a Douglas fir log incubated in vitro with [ 14 C]lignocellulose in a defined mineral salts medium supplemented with 10 mg of N liter -1 of 15 N-labeled NO 3 - (50 atom % 15 N). Evolution of 14 CO 2 , distribution and isotopic dilution of 15 N, filtrate N concentrations, and the rates of denitrification, N 2 fixation, and respiration were measured at 6, 12, and 18 days of incubation. The organic N content of the lignocellulose-wood sample mixture had increased from 132 μg of N to a maximum of 231 μg of N per treatment after 6 days of incubation. Rates of [ 14 C]lignocellulose decomposition were greatest during the first 6 days and then began to decline over the remaining 12 days. Total CO 2 evolution was also highest at day 6 and declined steadily over the remaining duration of the incubation. Filtrate NH 4 + -N increased from background levels to a final value of 57 μg of N per treatment. Filtrate NO 3 - N completely disappeared by day 6, and organic N showed a slight decline between days 12 and 18. The majority of the 15 N that could be recovered appeared in the particulate organic fraction by day 6 (41 μg of N), and the filtrate NH 4 + N fraction contained 11 μg of 15 N by day 18. The 15 N enrichment values of the filtrate NH 4 + and the inorganic N associated with the particulate fraction had increased to approximately 20 atom % 15 N by 18 days of incubation, whereas the particulate organic fraction reached its highest enrichment by day 6. Measurements of N 2 fixation and denitrification indicated an insignificant gain or loss of N from the experimental system by these processes. The data show that woody debris in stream ecosystems might function as a rapid and efficient sink for exogenous N, resulting in stimulation of wood decomposition and subsequent activation of other N cycling processes

Can δ(15)N in lettuce tissues reveal the use of synthetic nitrogen fertiliser in organic production?

Science.gov (United States)

Sturm, Martina; Kacjan-Maršić, Nina; Lojen, Sonja

2011-01-30

The nitrogen isotopic fingerprint (δ(15)N) is reported to be a promising indicator for differentiating between organically and conventionally grown vegetables. However, the effect on plant δ(15)N of split nitrogen fertilisation, which could enable farmers to cover up the use of synthetic fertiliser, is not well studied. In this study the use of δ(15)N in lettuce as a potential marker for identifying the use of synthetic nitrogen fertiliser was tested on pot-grown lettuce (Lactuca sativa L.) treated with synthetic and organic nitrogen fertilisers (single or split application). The effect of combined usage of synthetic and organic fertilisers on δ(15)N was also investigated. The δ(15)N values of whole plants treated with different fertilisers differed significantly when the fertiliser was applied in a single treatment. However, additional fertilisation (with isotopically the same or different fertiliser) did not cause a significant alteration of plant δ(15)N. The findings of the study suggest that the δ(15)N value of lettuce tissues could be used as a rough marker to reveal the history of nitrogen fertilisation, but only in the case of single fertiliser application. However, if the difference in δ(15)N between the applied synthetic and organic nitrogen fertilisers was > 9.1 ‰, the detection of split and combined usage of the fertilisers would have greater discriminatory power. 2010 Society of Chemical Industry.