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Sample records for na isotopes maintained

  1. Exploring Neutron-Rich Oxygen Isotopes with MoNA

    CERN Document Server

    Frank, N; Bazin, D; Brown, J; DeYoung, P A; Finck, J E; Gade, A; Hinnefeld, J; Howes, R; Lecouey, J -L; Luther, B; Peters, W A; Scheit, H; Schiller, A; Thoennessen, M

    2007-01-01

    The Modular Neutron Array (MoNA) was used in conjunction with a large-gap dipole magnet (Sweeper) to measure neutron-unbound states in oxygen isotopes close to the neutron dripline. While no excited states were observed in 24O, a resonance at 45(2) keV above the neutron separation energy was observed in 23O.

  2. Maintaining K+ balance on the low-Na+, high-K+ diet

    Science.gov (United States)

    Cornelius, Ryan J.; Wang, Bangchen; Wang-France, Jun

    2016-01-01

    A low-Na+, high-K+ diet (LNaHK) is considered a healthier alternative to the “Western” high-Na+ diet. Because the mechanism for K+ secretion involves Na+ reabsorptive exchange for secreted K+ in the distal nephron, it is not understood how K+ is eliminated with such low Na+ intake. Animals on a LNaHK diet produce an alkaline load, high urinary flows, and markedly elevated plasma ANG II and aldosterone levels to maintain their K+ balance. Recent studies have revealed a potential mechanism involving the actions of alkalosis, urinary flow, elevated ANG II, and aldosterone on two types of K+ channels, renal outer medullary K+ and large-conductance K+ channels, located in principal and intercalated cells. Here, we review these recent advances. PMID:26739887

  3. Maintaining K(+) balance on the low-Na(+), high-K(+) diet.

    Science.gov (United States)

    Cornelius, Ryan J; Wang, Bangchen; Wang-France, Jun; Sansom, Steven C

    2016-04-01

    A low-Na(+), high-K(+) diet (LNaHK) is considered a healthier alternative to the "Western" high-Na(+) diet. Because the mechanism for K(+) secretion involves Na(+) reabsorptive exchange for secreted K(+) in the distal nephron, it is not understood how K(+) is eliminated with such low Na(+) intake. Animals on a LNaHK diet produce an alkaline load, high urinary flows, and markedly elevated plasma ANG II and aldosterone levels to maintain their K(+) balance. Recent studies have revealed a potential mechanism involving the actions of alkalosis, urinary flow, elevated ANG II, and aldosterone on two types of K(+) channels, renal outer medullary K(+) and large-conductance K(+) channels, located in principal and intercalated cells. Here, we review these recent advances. Copyright © 2016 the American Physiological Society.

  4. Homeostatically maintained resting naïve CD4+ T cells resist latent HIV reactivation

    Directory of Open Access Journals (Sweden)

    Yasuko Tsunetsugu-Yokota

    2016-12-01

    Full Text Available Homeostatic proliferation (HSP is a major mechanism by which long-lived naïve and memory CD4+ T cells are maintained in vivo and suggested to contribute to the persistence of the latent HIV-1 reservoir. However, while many in vitro latency models rely on CD4+ T cells that were initially differentiated via T-cell receptor stimulation (TCR into memory/effector cells, latent infection of naïve resting CD4+ T cells maintained under HSP conditions has not been fully addressed. Here we describe an in vitro HSP culture system utilizing the cytokines IL-7 and IL-15 that allows studying latency in naïve resting CD4+ T cells. CD4+ T cells isolated from several healthy donors were infected with HIV pseudotypes expressing GFP and cultured under HSP conditions or TCR conditions as control. Cell proliferation, phenotype and GFP expression were analyzed by flow cytometry. RNA expression was quantified by qRT-PCR. Under HSP culture conditions, latently HIV-1 infected naïve cells are in part maintained in the non-dividing (= resting state. Although a few HIV-1 provirus+ cells were present in these resting GFP negative cells, the estimated level of GFP transcripts per infected cell seems to indicate a block at the post-transcriptional level. Interestingly, neither TCR nor the prototypic HDAC inhibitor SAHA were able to reactivate HIV-1 provirus from these cells. This lack of reactivation was not due to methylation of the HIV LTR. These results point to a mechanism of HIV control in HSP-cultured resting naïve CD4+ T cells that may be distinct from that in TCR-stimulated memory/effector T cells.

  5. Measurements of interaction cross sections for 22–35Na isotopes

    Directory of Open Access Journals (Sweden)

    Suzuki S.

    2014-03-01

    Full Text Available Interaction cross sections (σI for 22−35Na isotopes from the stability line to the vicinity of the neutron drip line have been measured at around 240 MeV/nucleon. The σI for 33−35Na were measured for the first time. Enhancement in cross sections is clearly observed from the systematics for stable nuclei, for isotopes with large mass numbers. From the known values of the nuclear-deformation parameters β2 of 22−31Na, these enhancement can be mainly ascribed to the nuclear deformation. Large enhancement in heavier isotopes suggest that these nuclei are strongly deformed. The root-mean-square (RMS nuclear matter radii were deduced from the σI by using Glauber-type calculation. Furthermore, a monotonic growth of the neutron-skin thickness has been deduced with increasing neutron number for Na isotopes.

  6. Maintaining consistent traceability in high precision isotope measurements of CO2: verifying atmospheric trends of δ13C

    Directory of Open Access Journals (Sweden)

    Y.-S. Lee

    2012-06-01

    Full Text Available Maintaining consistent traceability of high precision measurements of CO2 isotopes is critical in being able to observe accurate atmospheric trends of δ13C (CO2. Although a number of laboratories/organizations around the world have been involved in baseline measurements of atmospheric CO2 isotopes for several decades, the reports on their traceability measures are rare. In this paper, a principle and an approach for the traceability maintenance of high precision isotope measurements (δ13C and δ18O in atmospheric CO2 is described. The uncertainties of the traceability have been estimated based on the history of annual calibrations over the last 10 yr. The overall uncertainties of CO2 isotope measurements for individual ambient samples carried out by our program at Environment Canada are estimated (excluding the uncertainty associated with the sampling. The values are 0.02‰ and 0.05‰ in δ13C and δ18O, respectively, close to the WMO targets for data compatibility. The annual rate of change in δ13C of the primary anchor used in our program (which is the laboratory standard linking ambient measurements back to the primary VPDB scale is close to zero (−0.0016 ± 0.0012‰ per year over the period of 10 yr (2001–2011. The average annual decreasing rate of δ13C in air CO2 measurements at Alert over the period from 1999 to 2010 has been confirmed and verified, which is −0.025 ± 0.003‰ per year. The total change of δ13C in the annual mean value during this period is ∼−0.27‰. The concept of "Big Delta" is introduced and its role in maintaining traceability of the isotope measurements is described and discussed extensively. Finally, the challenges and a strategy for maintaining traceability are also discussed and suggested.

  7. Maintaining high precision of isotope ratio analysis over extended periods of time.

    Science.gov (United States)

    Brand, Willi A

    2009-06-01

    Stable isotope ratios are reliable and long lasting process tracers. In order to compare data from different locations or different sampling times at a high level of precision, a measurement strategy must include reliable traceability to an international stable isotope scale via a reference material (RM). Since these international RMs are available in low quantities only, we have developed our own analysis schemes involving laboratory working RM. In addition, quality assurance RMs are used to control the long-term performance of the delta-value assignments. The analysis schemes allow the construction of quality assurance performance charts over years of operation. In this contribution, the performance of three typical techniques established in IsoLab at the MPI-BGC in Jena is discussed. The techniques are (1) isotope ratio mass spectrometry with an elemental analyser for delta(15)N and delta(13)C analysis of bulk (organic) material, (2) high precision delta(13)C and delta(18)O analysis of CO(2) in clean-air samples, and (3) stable isotope analysis of water samples using a high-temperature reaction with carbon. In addition, reference strategies on a laser ablation system for high spatial resolution delta(13)C analysis in tree rings is exemplified briefly.

  8. Study for Nuclear Structures of 22-35Na Isotopes via Measurements of Reaction Cross Sections

    Science.gov (United States)

    Suzuki, Shinji

    2014-09-01

    T. Ohtsubo, M. Nagashima, T. Ogura, Y. Shimbara (Grad. Sch. of Sc., Niigata Univ.), M.Takechi, H. Geissel, M. Winkler (GSI), D. Nishimura, T. Sumikama (Dept. of Phys., Tokyo Univ. of Sc.), M. Fukuda, M. Mihara, H. Uenishi (Dept. of Phys., Osaka Univ.), T. Kuboki, T. Suzuki, T. Yamaguchi, H. Furuki, C. S. Lee, K. Sato (Dept. of Phys., Saitama Univ.), A. Ozawa, H. Ohnishi, T. Moriguchi, S. Fukuda, Y. Ishibashi, D. Nagae, R. Nishikiori, T. Niwa (Inst. of Phys., Univ. of Tsukuba), N. Aoi (RCNP), Rui-Jiu Chen, N. Inabe, D. Kameda, T. Kubo, M. Lantz, T. Ohnishi, K. Okumura, H. Sakurai, H. Suzuki, H. Takeda, S. Takeuchi, K. Tanaka, Y. Yanagisawa (RIKEN), De-Qing Fang, Yu-Gang Ma (SINAP), T. Izumikawa (RI Ctr., Niigata Univ.), and S. Momota (Fac. of Engn., Kochi Univ. of Tech.) Reaction cross sections (σR) for 22-35Na isotopes have been measured at around 240 MeV/nucleon. The σR for 22-35Na were measured for the first time. Enhancement in cross sections is clearly observed from the systematics for stable nuclei, for isotopes with large mass numbers. These enhancement can be mainly ascribed to the nuclear deformation. We will discuss the nuclear structure (neutron skin, nuclear shell structure) for neutron-excess Na isotopes. T. Ohtsubo, M. Nagashima, T. Ogura, Y. Shimbara (Grad. Sch. of Sc., Niigata Univ.), M.Takechi, H. Geissel, M. Winkler (GSI), D. Nishimura, T. Sumikama (Dept. of Phys., Tokyo Univ. of Sc.), M. Fukuda, M. Mihara, H. Uenishi (Dept. of Phys., Osaka Univ.), T. Kuboki, T. Suzuki, T. Yamaguchi, H. Furuki, C. S. Lee, K. Sato (Dept. of Phys., Saitama Univ.), A. Ozawa, H. Ohnishi, T. Moriguchi, S. Fukuda, Y. Ishibashi, D. Nagae, R. Nishikiori, T. Niwa (Inst. of Phys., Univ. of Tsukuba), N. Aoi (RCNP), Rui-Jiu Chen, N. Inabe, D. Kameda, T. Kubo, M. Lantz, T. Ohnishi, K. Okumura, H. Sakurai, H. Suzuki, H. Takeda, S. Takeuchi, K. Tanaka, Y. Yanagisawa (RIKEN), De-Qing Fang, Yu-Gang Ma (SINAP), T. Izumikawa (RI Ctr., Niigata Univ.), and S. Momota (Fac. of Engn

  9. Production of Nuclear Polarization of Na Isotopes at ISAC/TRIUMF and its Hyperfine Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Minamisono, K., E-mail: minamiso@nscl.msu.edu [NSCL/MSU (United States); Matsuta, K.; Minamisono, T. [Osaka University, Department of Physics (Japan); Levy, C. D. P. [TRIUMF (Canada); Nagatomo, T.; Ogura, M. [Osaka University, Department of Physics (Japan); Sumikama, T. [RIKEN (Japan); Behr, J. A.; Jackson, K. P. [TRIUMF (Canada); Fujiwara, H.; Mihara, M.; Fukuda, M. [Osaka University, Department of Physics (Japan)

    2004-12-15

    Hyperfine interactions of Na isotopes in single crystals have been studied using highly nuclear polarized {sup 20,21,26,27,28}Na beams provided by ISAC/TRIUMF. The degree of polarization kept in the crystals, the spin-lattice relaxation times, the electric quadrupole coupling constants and the initial distribution of the populations were measured. Such knowledge is indispensable for the application of the hyperfine interactions in the study of precision measurements such as the nuclear structure through nuclear moments and the fundamental symmetries.

  10. Investigation of the single Particle Structure of the neutron-rich Sodium Isotopes $^{27-31}\\!$Na

    CERN Multimedia

    2002-01-01

    We propose to study the single particle structure of the neutron-rich isotopes $^{27-31}\\!$Na. These isotopes will be investigated via neutron pickup reactions in inverse kinematics on a deuterium and a beryllium target. Scattered beam particles and transfer products are detected in a position sensitive detector located around 0$^\\circ$. De-excitation $\\gamma$-rays emitted after an excited state has been populated will be registered by the MINIBALL Germanium array. The results will shed new light on the structure of the neutron-rich sodium isotopes and especially on the region of strong deformation around the N=20 nucleus $^{31}\\!$Na.

  11. Coulomb breakup of neutron-rich $^{29,30}$Na isotopes near the island of inversion

    CERN Document Server

    Rahaman, A; Aumann, T; Beceiro-Novo, S; Boretzky, K; Caesar, C; Carlson, B V; Catford, W N; Chakraborty, S; Chartier, M; Cortina-Gil, D; Angelis, G De; Gonzalez-Diaz, D; Emling, H; Fernandez, P Diaz; Fraile, L M; Ershova, O; Geissel, H; Jonson, B; Johansson, H; Kalantar-Nayestanaki, N; Krücken, R; Kröll, T; Kurcewicz, J; Langer, C; Bleis, T Le; Leifels, Y; Münzenberg, G; Marganiec, J; Nilsson, T; Nociforo, C; Nowacki, F; Najafi, A; Panin, V; Paschalis, S; Plag, R; Poves, A; Ray, I; Reifarth, R; Rigollet, C; Ricciardi, V; Rossi, D; Scheit, H; Simon, H; Scheidenberger, C; Typel, S; Taylor, J; Togano, Y; Volkov, V; Weick, H; Wagner, A; Wamers, F; Weigand, M; Winfield, J S; Yakorev, D; Zoric, M

    2016-01-01

    First results are reported on the ground state configurations of the neutron-rich $^{29,30}$Na isotopes, obtained via Coulomb dissociation (CD) measurements as a method of the direct probe. The invariant mass spectra of those nuclei have been obtained through measurement of the four-momentum of all decay products after Coulomb excitation on a $^{208}Pb$ target at energies of 400-430 MeV/nucleon using FRS-ALADIN-LAND setup at GSI, Darmstadt. Integrated Coulomb-dissociation cross-sections (CD) of 89 $(7)$ mb and 167 $(13)$ mb up to excitation energy of 10 MeV for one neutron removal from $^{29}$Na and $^{30}$Na respectively, have been extracted. The major part of one neutron removal, CD cross-sections of those nuclei populate core, in its' ground state. A comparison with the direct breakup model, suggests the predominant occupation of the valence neutron in the ground state of $^{29}$Na${(3/2^+)}$ and $^{30}$Na${(2^+)}$ is the $d$ orbital with small contribution in the $s$-orbital which are coupled with ground ...

  12. Consistent Data Assimilation of Structural Isotopes: 23Na and 56Fe

    Energy Technology Data Exchange (ETDEWEB)

    Giuseppe Palmiotti

    2010-09-01

    A new approach is proposed, the consistent data assimilation, that allows to link the integral data experiment results to basic nuclear parameters employed by evaluators to generate ENDF/B point energy files in order to improve them. Practical examples are provided for the structural materials 23Na and 56Fe. The sodium neutron propagation experiments, EURACOS and JANUS-8, are used to improve via modifications of 23Na nuclear parameters (like scattering radius, resonance parameters, Optical model parameters, Statistical Hauser-Feshbach model parameters, and Preequilibrium Exciton model parameters) the agreement of calculation versus experiments for a series of measured reaction rate detectors slopes. For the 56Fe case the EURACOS and ZPR3 assembly 54 are used. Results have shown inconsistencies in the set of nuclear parameters used so that further investigation is needed. Future work involves comparison of results against a more traditional multigroup adjustments, and extension to other isotope of interest in the reactor community.

  13. Precision mass measurements of very short-lived, neutron-rich Na isotopes using a radiofrequency spectrometer

    CERN Document Server

    Lunney, M D; Doubre, H; Henry, S; Monsanglant, C; De Saint-Simon, M; Thibault, C; Toader, C F; Borcea, C; Bollen, G

    2001-01-01

    Mass measurements of high precision have been performed on sodium isotopes out to $^{30}$Na using a new technique of radiofrequency excitation of ion trajectories in a homogeneous magnetic field. This method, especially suited to very short-lived nuclides, has allowed us to significantly reduce the uncertainty in mass of the most exotic Na isotopes: a relative error of 5x10$^{-7}$ was achieved for $^{28}$Na having a half-life of only 30.5 ms and 9x10$^{-7}$ for the weakly produced $^{30}$Na. Verifying and minimizing binding energy uncertainties in this region of the nuclear chart is important for clarification of a long standing problem concerning the strength of the $N$=20 magic shell closure. These results are the fruit of the commissioning of the new experimental program Mistral.

  14. Maintaining consistent traceability in high-precision isotope measurements of CO2: a way to verify atmospheric trends of δ13C and δ18O

    Directory of Open Access Journals (Sweden)

    L. Huang

    2013-07-01

    Full Text Available Maintaining consistent traceability of high-precision measurements of CO2 isotopes is critical in order to obtain accurate atmospheric trends of δ13C and δ18O (in CO2. Although a number of laboratories/organizations around the world have been conducting baseline measurements of atmospheric CO2 isotopes for several decades, reports on the traceability and maintenance are rare. In this paper, a principle and an approach for maintaining consistent traceability in high-precision isotope measurements (δ13C and δ18O of atmospheric CO2 are described. The concept of Big Delta is introduced and its role in maintaining traceability of the isotope measurements is described and discussed extensively. The uncertainties of the traceability have been estimated based on annual calibration records over the last 10 yr. The overall uncertainties of CO2 isotope measurements for individual ambient samples analyzed by the program at Environment Canada have been estimated (excluding these associated with the sampling. The values are 0.02 and 0.05‰ in δ13C and δ18O, respectively, which are close to the World Meteorological Organization (WMO targets for data compatibility. The annual rates of change in δ13C and δ18O of the primary anchor (which links the flask measurements back to the VPDB-CO2 scale are close to zero (−0.0016 ± 0.0012‰, and −0.006 ± 0.003‰ per year, respectively over a period of 10 yr (2001–2011. The average annual changes of δ13C and δ18O in air CO2 at Alert GAW station over the period from 1999 to 2010 have been evaluated and confirmed; they are −0.025 ± 0.003‰ and 0.000 ± 0.010‰, respectively. The results are consistent with a continuous contribution of fossil fuel CO2 to the atmosphere, having a trend toward more negative in δ13C, whereas the lack of change in δ18O likely reflects the influence from the global hydrologic cycle. The total change of δ13C and δ18O during this period is ~0.27‰ and ~0.00

  15. Thyroid screening of members of the public for iodine isotopes with portable NaI detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, John G., E-mail: john@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ),Rio de Janeiro, RJ (Brazil)

    2014-07-01

    In the case of an accident in a nuclear power plant with radionuclide releases to the environment, members of the public with possible internal contamination with radioactive isotopes of iodine should be screened to identify cases where a more detailed evaluation and medical follow-up is necessary. Screening of large numbers of the public can be performed with a quick measuring protocol using hand held unshielded NaI based detectors giving results in cps. The screening geometry was simulated using the Monte Carlo code Visual Monte Carlo. The results show that for a geometry with the NaI detector near the skin in front of the thyroid, the interference of the gamma radiation coming from other radionuclides released in the accident either deposited in the lung or in the whole body is sufficiently low to allow thyroid screening criteria to be established. The screening criteria were developed using 5, 10 and 15 year old hybrid phantoms and for the adult male based on the ICRP reference voxel phantom. (author)

  16. Lotus tenuis tolerates combined salinity and waterlogging: maintaining O2 transport to roots and expression of an NHX1-like gene contribute to regulation of Na+ transport.

    Science.gov (United States)

    Teakle, Natasha L; Amtmann, Anna; Real, Daniel; Colmer, Timothy D

    2010-08-01

    Salinity and waterlogging interact to reduce growth for most crop and pasture species. The combination of these stresses often cause a large increase in the rate of Na(+) and Cl(-) transport to shoots; however, the mechanisms responsible for this are largely unknown. To identify mechanisms contributing to the adverse interaction between salinity and waterlogging, we compared two Lotus species with contrasting tolerances when grown under saline (200 mM NaCl) and O(2)-deficient (stagnant) treatments. Measurements of radial O(2) loss (ROL) under stagnant conditions indicated that more O(2) reaches root tips of Lotus tenuis, compared with Lotus corniculatus. Better internal aeration would contribute to maintaining Na(+) and Cl(-) transport processes in roots of L. tenuis exposed to stagnant-plus-NaCl treatments. L. tenuis root Na(+) concentrations after stagnant-plus-NaCl treatment (200 mM) were 17% higher than L. corniculatus, with 55% of the total plant Na(+) being accumulated in roots, compared with only 39% for L. corniculatus. L. tenuis accumulated more Na(+) in roots, presumably in vacuoles, thereby reducing transport to the shoot (25% lower than L. corniculatus). A candidate gene for vacuole Na(+) accumulation, an NHX1-like gene, was cloned from L. tenuis and identity established via sequencing and yeast complementation. Transcript levels of NHX1 in L. tenuis roots under stagnant-plus-NaCl treatment were the same as for aerated NaCl, whereas L. corniculatus roots had reduced transcript levels. Enhanced O(2) transport to roots enables regulation of Na(+) transport processes in L. tenuis roots, contributing to tolerance to combined salinity and waterlogging stresses.

  17. SbHKT1;4, a member of the high-affinity potassium transporter gene family from Sorghum bicolor, functions to maintain optimal Na+/K+ balance under Na+ stress

    Institute of Scientific and Technical Information of China (English)

    Tian-Tian Wang; Zhi-Jie Ren; Zhi-Quan Liu; Xue Feng; Rui-Qi Guo; Bao-Guo Li; Le-Gong Li; HaiChun Jing

    2014-01-01

    In halophytic plants, the high-affinity potassium transporter HKT gene family can selectively uptake Kþ in the presence of toxic concentrations of Naþ. This has so far not been well examined in glycophytic crops. Here, we report the characterization of SbHKT1;4, a member of the HKT gene family from Sorghum bicolor. Upon Naþ stress, SbHKT1;4 expression was more strongly upregulated in salt-tolerant sorghum accession, correlating with a better balanced Naþ/Kþ ratio and enhanced plant growth. Heterogeneous expression analyses in mutants of Saccharomyces cerevisiae and Arabidopsis thaliana indicated that overexpressing SbHKT1;4 resulted in hypersensitivity to Naþ stress, and such hypersensitivity could be alleviated with the supply of elevated levels of Kþ, implicating that SbHKT1;4 may mediate Kþ uptake in the presence of excessive Naþ. Further electrophysiological evidence demonstrated that SbHKT1;4 could transport Naþ and Kþ when expressed in Xenopus laevis oocytes. The relevance of the finding that SbHKT1;4 functions to maintain optimal Naþ/Kþ balance under Naþ stress to the breeding of salt-tolerant glycophytic crops is discussed.

  18. Comparison of LaBr3:Ce and NaI(Tl) Scintillators for Radio-Isotope Identification Devices

    Energy Technology Data Exchange (ETDEWEB)

    Milbrath, Brian D.; Choate, Bethany J.; Fast, Jim E.; Hensley, Walter K.; Kouzes, Richard T.; Schweppe, John E.

    2006-07-31

    Lanthanum halide (LaBr3:Ce) scintillators offer significantly better resolution (<3 percent at 662 kilo-electron volt [keV]) relative to sodium iodide (NaI(Tl)) and have recently become commercially available in sizes large enough for the hand-held radio-isotope identification device (RIID) market. There are drawbacks to lanthanum halide detectors, however. These include internal radioactivity that contributes to spectral counts and a low-energy response that can cause detector resolution to be lower than that of NaI(Tl) below 100 keV. To study the potential of this new material for RIIDs, we performed a series of measurements comparing a 1.5?1.5 inch LaBr?3:Ce detector with an Exploranium GR 135 RIID, which contains a 1.5-2.2 inch NaI(Tl) detector. Measurements were taken for short time frames, as typifies RIID usage. Measurements included examples of naturally occurring radioactive material (NORM), typically found in cargo, and special nuclear materials. Some measurements were noncontact, involving short distances or cargo shielding scenarios. To facilitate direct comparison, spectra from the different detectors were analyzed with the same isotope identification software (ORTEC ScintiVision TM). In general, the LaBr3:Ce detector was able to find more peaks and find them faster than the NaI(Tl) detector. To the same level of significance, the LaBr3:Ce detector was usually two to three times faster. The notable exception was for 40K containing NORM where interfering internal contamination in the LaBr3:Ce detector exist. NaI(Tl) consistently outperformed LaBr3:Ce for this important isotope. LaBr3:Ce currently costs much more than NaI(Tl), though this cost-difference is expected to diminish (but not completely) with time. As is true of all detectors, LaBr3:Ce will need to be gain-stabilized for RIID applications. This could possibly be done using the internal contaminants themselves. It is the experience of the authors that peak finding software in RIIDs needs to be

  19. Activity of the Na,K-ATPase alpha4 isoform is important for membrane potential, intracellular Ca2+, and pH to maintain motility in rat spermatozoa.

    Science.gov (United States)

    Jimenez, Tamara; Sánchez, Gladis; Wertheimer, Eva; Blanco, Gustavo

    2010-05-01

    While the function of the ubiquitous Na,K-ATPase alpha1 subunit has been well documented, the role of the sperm-specific alpha4 isoform of this ion transporter is less known. We have explored the importance of alpha4 in rat sperm physiology by taking advantage of the high sensitivity of this isoform for the inhibitor ouabain. Using concentrations that selectively block alpha4 activity, we found ouabain to reduce not only sperm total motility, but also multiple parameters of sperm movement, including progressive motility, straight line, curvilinear, and average path velocities, lateral head displacement, beat cross frequency, and linearity. According to a direct role of alpha4 in Na(+) transport, ouabain inhibition of alpha4 increased [Na(+)](i) in the male gametes. In addition, interference of alpha4 activity with ouabain produced cell membrane depolarization, diminished pH, and increased [Ca(2)(+)](i) in spermatozoa. Inhibition of alpha4 was sufficient to cause all these effects and additional blockage of alpha1, the other Na,K-ATPase alpha isoform expressed in sperm, and higher doses of ouabain did not result in further changes in the cell parameters studied. These results show that alpha4 is the Na,K-ATPase isoform primarily involved in controlling the transmembrane Na(+) gradient in sperm, and that alpha4 activity is necessary for maintaining membrane potential, [Ca(2)(+)](i), and [H(+)](i) in the cells. The high dependence of sperm motility on membrane excitability, [Ca(2)(+)](i), and acid-base balance suggests that their regulation is the mechanism by which alpha4 maintains motility of the male gametes.

  20. Half lives of exotic sodium isotopes /sup 28-34/Na

    CERN Document Server

    Thibault, C; Epherre-Rey-Campagnolle, Marcelle; Guillemaud, D; Huber, G; Klapisch, Robert; Naulin, F; Touchard, F

    1981-01-01

    The half lives of /sup 33/Na (T/sub 1/2/=8.2+or-.4 ms) and /sup 34/Na (T/sub 1/2/=4.6+or-.9 ms) have been measured by means of ion counting following on-line mass spectrometry. New measurements of the half lives of /sup 28-32/Na are also reported. (8 refs).

  1. Morphological Structure and Transcriptome Comparison of the Cytoplasmic Male Sterility Line in Brassica napus (SaNa-1A) Derived from Somatic Hybridization and Its Maintainer Line SaNa-1B

    Science.gov (United States)

    Du, Kun; Liu, Qier; Wu, Xinyue; Jiang, Jinjin; Wu, Jian; Fang, Yujie; Li, Aimin; Wang, Youping

    2016-01-01

    SaNa-1A is a novel cytoplasmic male sterility (CMS) line in Brassica napus derived from progenies of somatic hybrids between B.napus and Sinapis alba, and SaNa-1B is the corresponding maintainer line. In this study, phenotypic differences of floral organs between CMS and the maintainer lines were observed. By microscope observation in different anther developmental stages of two lines, we found the anther development in SaNa-1A was abnormal since the tetrad stage, and microspore development was ceased during the uninucleate stage. Transcriptomic sequencing for floral buds of sterile and fertile plants were conducted to elucidate gene expression and regulation caused by the alien chromosome and cytoplasm from S. alba. Clean tags obtained were assembled into 195,568 unigenes, and 7811 unigenes distributed in the metabolic and protein synthesis pathways were identified with significant expression differences between two libraries. We also observed that genes participating in carbon metabolism, tricarboxylic acid cycle, oxidative phosphorylation, oxidation–reduction system, pentatricopeptide repeat, and anther development were downregulated in the sterile line. Some of them are candidates for researches on the sterility mechanism in the CMS material, fertility restoration, and improvement of economic traits in the maintainer line. Further research on the tags with expressional specificity in the fertile line would be helpful to explore desirable agronomic traits from wild species of rapeseed. PMID:27656189

  2. Stable isotope labelling reveals that NaCl stress decreases the production of Ensifer (Sinorhizobium) arboris lipochitooligosaccharide signalling molecules.

    Science.gov (United States)

    Penttinen, Petri; Räsänen, Leena A; Lortet, Gilles; Lindström, Kristina

    2013-12-01

    Ensifer (Sinorhizobium) arboris is a symbiont of salt-tolerant leguminous trees in the genera Acacia and Prosopis that are utilized in the prevention of soil erosion and desertification and in phytoremediation of salinized soil. Signalling between the plant and the rhizobia is essential for the formation of effective symbiosis that increases the success of reclaiming saline sites. We assessed the effect of salt stress on the growth and the production of lipochitooligosaccharide signalling molecules (LCOs) of S. arboris HAMBI 2361, an LCO-overproducing derivative of the S. arboris type strain HAMBI 1552. The strain tolerated NaCl up to 750 mM. To obtain both qualitative and quantitative information on the LCO production under salt stress, we devised a method where LCOs were differentially labelled by stable isotopes of nitrogen, (14)N and (15)N, and analysed by mass spectrometry. Under control conditions, the strain produced altogether 27 structural LCO variants. In 380 mM NaCl, 13 LCO variants were produced in detectable amounts, and six of these were reliably quantified, ranging from one-tenth to one-third of the non-stressed one.

  3. FXYD1, a modulator of Na+,K+-ATPase activity, facilitates female sexual development by maintaining GnRH neuronal excitability

    Science.gov (United States)

    Garcia-Rudaz, Cecilia; Deng, Vivianne; Matagne, Valerie; Ronnekleiv, Oline; Bosch, Martha; Han, Victor; Percy, Alan K.; Ojeda, Sergio R.

    2009-01-01

    The excitatory tone to GnRH neurones is a critical component underlying the pubertal increase in GnRH secretion. However, the homeostatic mechanisms modulating the response of GnRH neurones to excitatory inputs remain poorly understood. A basic mechanism of neuronal homeostasis is the Na+, K+-ATPase-dependent restoration of Na+ and K+ transmembrane gradients after neuronal excitation. This activity is reduced in a mouse model of Rett syndrome (RTT), a neurodevelopmental disorder in which expression of FXYD1, a modulator of Na+, K+-ATPase activity, is increased. We now report that the initiation, but not the completion of puberty, is advanced in girls with RTT, and that in rodents FXYD1 may contribute to the neuroendocrine regulation of female puberty by modulating GnRH neuronal excitability. Fxyd1 mRNA abundance reaches maximal levels in the female rat hypothalamus by the fourth postnatal week of life, i.e., around the time when the mode of GnRH secretion acquires an adult pattern of release. Although Fxyd1 mRNA expression is low in the hypothalamus, about 50% of GnRH neurones contain Fxyd1 transcripts. Whole-cell patch recording of GnRH-EGFP neurones revealed that the neurones of Fxyd1-null female mice respond to somatic current injections with a lower number of action potentials than wild-type cells. Both the age at vaginal opening and at first oestrous were delayed in Fxyd1-/- mice, but adult reproductive capacity was normal. These results suggest that FXYD1 contributes to facilitating the advent of puberty by maintaining GnRH neuronal excitability to incoming transsynaptic stimulatory inputs. PMID:19187398

  4. Study of single particle properties of neutron-rich Na isotopes on the "shore of the island of inversion" by means of neutron-transfer reactions

    CERN Multimedia

    Reiter, P; Blazhev, A A; Riisager, K; Bastin, B; Tengborn, E A; Kruecken, R; Voulot, D; Jeppesen, H B; Hadinia, B; Gernhaeuser, R A; Fynbo, H O U; Georgiev, G P; Habs, D; Fraile prieto, L M; Chapman, R; Nilsson, T; Diriken, J V J; Jenkins, D G; Kroell, T; Leske, J; Huyse, M L; Patronis, N

    We aim at the investigation of single particle properties of neutron-rich Na isotopes around the "shore of the island of inversion". As first experiment of this programme, we propose to study excited states in the isotope $^{29}$Na by a one-neutron transfer reaction with a $^{28}$Na beam at 3 MeV/u obtained from REX-ISOLDE impinging on a CD$_{2}$-target. The $\\gamma$-rays will be detected by the MINIBALL array and the particles by the T-REX array of segmented Si detectors. The main physics aims are to extract from the relative spectroscopic factors information on the configurations contributing to the wave functions of the populated states and, secondly, to identify and characterize negative parity states whose excitation energies reflect directly the N= 28 gap in this region. The results will be compared to recent shell model calculations involving new residual interactions. This will shed new light on the evolution of single particle structure and help to understand the underlying physics relevant for the f...

  5. The effects of CaNa(2)EDTA on brain lead mobilization in rodents determined using a stable lead isotope tracer.

    Science.gov (United States)

    Seaton, C L; Lasman, J; Smith, D R

    1999-09-15

    Studies have demonstrated the efficacy of CaNa(2)EDTA for reducing lead (Pb) levels in blood and soft tissues, including brain. However, a concern remains that a single dose of CaNa(2)EDTA may cause a significant increase in brain Pb levels due to a redistribution of endogenous Pb. Here we utilized a rodent model of Pb exposure in combination with a sensitive stable Pb isotope tracer methodology to assess the effects of CaNa(2)EDTA chelation treatment on the redistribution of Pb in brain, blood, kidney, and bone tissues. Thirty-two adult female albino rats (n = 6-7 animals/group) were exposed to 100 microg Pb/mL in drinking water for 4 weeks. Stable (204)Pb tracer was administered via i.p. injection over 2 days prior to chelation. CaNa(2)EDTA was administered i.p. at a dose of 150 mg/kg/day for 1 to 5 days. Statistical differences were evaluated with univariate ANOVA. Under the Pb exposure and chelation treatment regimens utilized here, there was no evidence of a measurable redistribution of endogenous Pb (as total Pb or labile (204)Pb tracer) into the brain after a single CaNa(2)EDTA dose. Further, CaNa(2)EDTA was not efficacious in measurably reducing brain or bone Pb levels, although brain levels of labile (204)Pb tracer were significantly reduced after 5 days of chelation. CaNa(2)EDTA treatment was effective in significantly reducing both blood and kidney Pb levels. Overall, these data substantiate the efficacy of CaNa(2)EDTA for reducing soft tissue Pb levels, but not total brain Pb, and they do not support concern for a transient increase in brain Pb levels with treatment. Copyright 1999 Academic Press.

  6. Oxygen isotope systematics in the aragonite-CO2-H2O-NaCl system up to 0.7 mol/kg ionic strength at 25 °C

    Science.gov (United States)

    Kim, Sang-Tae; Gebbinck, Christa Klein; Mucci, Alfonso; Coplen, Tyler B.

    2014-01-01

    To investigate the oxygen isotope systematics in the aragonite-CO2-H2O-NaCl system, witherite (BaCO3) was precipitated quasi-instantaneously and quantitatively from Na-Cl-Ba-CO2 solutions of seawater-like ionic strength (I = 0.7 mol/kg) at two pH values (~7.9 and ~10.6) at 25 °C. The oxygen isotope composition of the witherite and the dissolved inorganic carbon speciation in the starting solution were used to estimate the oxygen isotope fractionations between HCO3¯ and H2O as well as between CO3 2 and H2O. Given the analytical error on the oxygen isotope composition of the witherite and uncertainties of the parent solution pH and speciation, oxygen isotope fractionation between NaHCO3° and HCO3¯, as well as between NaCO3¯ and CO3 2, is negligible under the experimental conditions investigated. The influence of dissolved NaCl concentration on the oxygen isotope fractionation in the aragonite-CO2-H2O-NaCl system also was investigated at 25 °C. Aragonite was precipitated from Na-Cl-Ca-Mg-(B)-CO2 solutions of seawater-like ionic strength using passive CO2 degassing or constant addition methods. Based upon our new experimental observations and published experimental data from lower ionic strength solutions by Kim et al. (2007b), the equilibrium aragonite-water oxygen isotope fractionation factor is independent of the ionic strength of the parent solution up to 0.7 mol/kg. Hence, our study also suggests that the aragonite precipitation mechanism is not affected by the presence of sodium and chloride ions in the parent solution over the range of concentrations investigated.

  7. Hydrogen sulfide is involved in maintaining ion homeostasis via regulating plasma membrane Na+/H+ antiporter system in the hydrogen peroxide-dependent manner in salt-stress Arabidopsis thaliana root.

    Science.gov (United States)

    Li, Jisheng; Jia, Honglei; Wang, Jue; Cao, Qianhua; Wen, Zichao

    2014-07-01

    Hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) function as the signaling molecules in plants responding to salt stresses. The present study presents a signaling network involving H2S and H2O2 in salt resistance pathway of the Arabidopsis root. Arabidopsis roots were sensitive to 100 mM NaCl treatment, which displayed a great increase in electrolyte leakage (EL) and Na(+)/K(+) ratio under salt stress. The treatment of H2S donors sodium hydrosulfide (NaHS) enhanced the salt tolerance by maintaining a lower Na(+)/K(+) ratio. In addition, the inhibition of root growth under salt stress was removed by H2S. Further studies indicated that H2O2 was involved in H2S-induced salt tolerance pathway. H2S induced the production of the endogenous H2O2 via regulating the activities of glucose-6-phosphate dehydrogenase (G6PDH) and plasma membrane (PM) NADPH oxidase, with the treatment with dimethylthiourea (DMTU, an ROS scavenger), diphenylene iodonium (DPI, a PM NADPH oxidase inhibitor), or glycerol (G6PDH inhibitor) removing the effect of H2S. Treatment with amiloride (an inhibitor of PM Na(+)/H(+) antiporter) and vanadate (an inhibitor of PM H(+)-ATPase) also inhibited the activity of H2S on Na(+)/K(+) ratio. Through an analysis of quantitative real-time polymerase chain reaction and Western blot, we found that H2S promoted the genes expression and the phosphorylation level of PM H(+)-ATPase and Na(+)/H(+) antiporter protein level. However, when the endogenous H2O2 level was inhibited by DPI or DMTU, the effect of H2S on the PM Na(+)/H(+) antiporter system was removed. Taken together, H2S maintains ion homeostasis in the H2O2-dependent manner in salt-stress Arabidopsis root.

  8. Study of Ground State Wave-function of the Neutron-rich 29,30Na Isotopes through Coulomb Breakup

    Directory of Open Access Journals (Sweden)

    Rahaman A.

    2014-03-01

    Full Text Available Coulomb breakup of unstable neutron rich nuclei 29,30Na around the ‘island of inversion’ has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s⊗νs1/2 and 29Na(g.s⊗νs1/2,respectively.

  9. The influence of isotope substitution of neon atom on the integral cross sections of rotational excitation in Ne-Na2 collisions

    Institute of Scientific and Technical Information of China (English)

    Zang Hua-Ping; Li Wen-Feng; Linghu Rong-Feng; Cheng Xin-Lu; Yang Xiang-Dong

    2011-01-01

    This paper applies the multiple ellipsoid model to the 16Ne (20Ne, 28Ne, 34Ne)-Na2 collision systems, and calculates integral cross sections for rotational excitation at the incident energy of 190 meV. It can be seen that the accuracy of the integral cross sections can be improved by increasing the number of equipotential ellipsoid surfaces. Moreover, by analysing the differences of these integral cross sections, it obtains the change rules of the integral cross sections with the increase of rotational angular quantum number J', and with the change of the mass of isotope substitution neon atom. Finally, the contribution of different regions of the potential to inelastic cross sections for 20Ne-Na2 collision system is investigated at relative incident energy of 190 meV.

  10. Production of cosmogenic isotopes 7Be, 10Be, 14C, 22Na and 36Cl in the atmosphere: Altitudinal profiles of yield functions

    CERN Document Server

    Poluianov, Stepan; Mishev, Alexander L; Usoskin, Ilya G

    2016-01-01

    New consistent and precise computations of the production of five cosmogenic radio-isotopes, 7Be, 10Be, 14C, 22Na and 36Cl, in the Earth's atmosphere by cosmic rays are presented in the form of tabulated yield functions. For the first time, a detailed set of the the altitude profiles of the production functions is provided which makes it possible to apply the results directly as input for atmospheric transport models. Good agreement with most of the earlier published works for columnar and global isotopic production rates is shown. Altitude profiles of the production are important, in particular for such tasks as studies of strong solar particle events in the past, precise reconstructions of solar activity on long-term scale, tracing air-mass dynamics using cosmogenic radio-isotopes, etc. As an example, computations of the $^{10}$Be deposition flux in the polar region are shown for the last decades and also for a period around 780 AD and confronted with the actual measurements in Greenland and Antarctic ice c...

  11. Hydrogen Sulfide Regulates Salt Tolerance in Rice by Maintaining Na+/K+ Balance, Mineral Homeostasis and Oxidative Metabolism Under Excessive Salt Stress

    Science.gov (United States)

    Mostofa, Mohammad G.; Saegusa, Daisuke; Fujita, Masayuki; Tran, Lam-Son Phan

    2015-01-01

    Being a salt sensitive crop, rice growth and development are frequently affected by soil salinity. Hydrogen sulfide (H2S) has been recently explored as an important priming agent regulating diverse physiological processes of plant growth and development. Despite its enormous prospects in plant systems, the role of H2S in plant stress tolerance is still elusive. Here, a combined pharmacological, physiological and biochemical approach was executed aiming to examine the possible mechanism of H2S in enhancement of rice salt stress tolerance. We showed that pretreating rice plants with H2S donor sodium bisulfide (NaHS) clearly improved, but application of H2S scavenger hypotaurine with NaHS decreased growth and biomass-related parameters under salt stress. NaHS-pretreated salt-stressed plants exhibited increased chlorophyll, carotenoid and soluble protein contents, as well as suppressed accumulation of reactive oxygen species (ROS), contributing to oxidative damage protection. The protective mechanism of H2S against oxidative stress was correlated with the elevated levels of ascorbic acid, glutathione, redox states, and the enhanced activities of ROS- and methylglyoxal-detoxifying enzymes. Notably, the ability to decrease the uptake of Na+ and the Na+/K+ ratio, as well as to balance mineral contents indicated a role of H2S in ion homeostasis under salt stress. Altogether, our results highlight that modulation of the level of endogenous H2S genetically or exogenously could be employed to attain better growth and development of rice, and perhaps other crops, under salt stress. Furthermore, our study reveals the importance of the implication of gasotransmitters like H2S for the management of salt stress, thus assisting rice plants to adapt to adverse environmental changes. PMID:26734015

  12. Hydrogen sulfide regulates salt tolerance in rice by maintaining Na+/K+ balance, mineral homeostasis and oxidative metabolism under excessive salt stress

    Directory of Open Access Journals (Sweden)

    Mohammad Golam Mostofa

    2015-12-01

    Full Text Available Being a salt sensitive crop, rice growth and development are frequently affected by soil salinity. Hydrogen sulfide (H2S has been recently explored as an important priming agent regulating diverse physiological processes of plant growth and development. Despite its enormous prospects in plant systems, the role of H2S in plant stress tolerance is still elusive. Here, a combined pharmacological, physiological and biochemical approach was executed aiming to examine the possible mechanism of H2S in enhancement of salt stress tolerance in rice. We show that pretreating rice plants with H2S donor sodium bisulfide (NaHS clearly improved, but application of H2S scavenger hypotaurine with NaHS decreased growth and biomass-related parameters under salt stress. NaHS-pretreated salt-stressed plants exhibited increased chlorophyll, carotenoid and soluble protein contents, as well as suppressed accumulation of reactive oxygen species (ROS, contributing to oxidative damage protection. The protective mechanism of H2S against oxidative stress was correlated with the elevated levels of ascorbic acid, glutathione, redox states, and the enhanced activities of ROS- and methylglyoxal-detoxifying enzymes. Notably, decreased uptake of Na+, decreased Na+/K+ ratio and balanced mineral contents indicated a role of H2S in ion homeostasis under salt stress. Altogether, our results highlight that modulation of the level of endogenous H2S genetically or exogenously could be employed to attain better growth and development of rice, and perhaps other crops, under salt stress. Furthermore, our study reveals the importance of the implication of gasotransmitter like H2S for the management of salt stress, thus assisting rice plants to adapt to adverse environmental changes.

  13. Effect of Na, Ca and pH on simultaneous uptake of Cd, Cu, Ni, Pb, and Zn in the water flea Daphnia magna measured using stable isotopes.

    Science.gov (United States)

    Komjarova, I; Blust, R

    2009-08-31

    The present study investigates the effects of Na(+), Ca(2+) and pH on the kinetics of Cd, Cu, Ni, Pb, and Zn uptake in Daphnia magna at low exposure concentrations measured using a stable isotope technique. Using experimental data the uptake rate constants were calculated for each metal individually on the basis of total metal concentrations. The copper uptake was not significantly affected by variations in chemical composition of the test medium. Calcium had a suppressing effect on the uptake of Cd, Ni, Pb and Zn. Specifically, Cd and Ni uptake rate constants decreased with increases in calcium concentrations from 0.1 to 2.5mM. The uptake of Zn and Pb was significantly suppressed only at 2.5mM Ca. The effect of sodium was less clear. There was no effect of varying sodium concentrations on the Ni uptake rate constants. Cd and Pb showed an increase in uptake rate constants at elevated sodium concentrations (2-8mM Na(+) for Cd and 8mM Na(+) for Pb). A bell-shaped response on increasing Na(+) concentrations was observed for Zn with a maximum value of uptake rate constant at the middle value (2mM Na(+)). Variation in pH of the medium affected Cd, Ni and Zn uptake processes. When Daphnia were exposed to acidic conditions (pH 6), the Cd and Ni uptake rate constants were the highest, while similarly low values were observed at neutral and basic conditions. In contrast, the uptake rates of Zn were linearly increasing with increasing pH of the medium.

  14. Tracing groundwater salinization processes in coastal aquifers: a hydrogeochemical and isotopic approach in the Na-Cl brackish waters of northwestern Sardinia, Italy

    Directory of Open Access Journals (Sweden)

    G. Mongelli

    2013-07-01

    Full Text Available Throughout the Mediterranean, salinization threatens water quality, especially in coastal areas. This salinization is the result of concomitant processes related to both seawater intrusion and water–rock interaction, which in some cases are virtually indistinguishable. In the Nurra region of northwestern Sardinia, recent salinization related to marine water intrusion has been caused by aquifer exploitation. However, the geology of this region records a long history from the Palaeozoic to the Quaternary, and is structurally complex and comprises a wide variety of lithologies, including Triassic evaporites. Determining the origin of the saline component of the Jurassic and Triassic aquifers in the Nurra region may provide a useful and more general model for salinization processes in the Mediterranean area, where the occurrence of evaporitic rocks in coastal aquifers is a common feature. In addition, due to intensive human activity and recent climatic change, the Nurra has become vulnerable to desertification and, in common with other Mediterranean islands, surface water resources periodically suffer from severe shortages. With this in mind, we report new data regarding brackish and surface waters (outcrop and lake samples of the Na-Cl type from the Nurra region, including major ions and selected trace elements (B, Br, I, and Sr, in addition to isotopic data including δ18O, δD in water, and δ34S and δ18O in dissolved SO4. To identify the origin of the salinity more precisely, we also analysed the mineralogical and isotopic composition of Triassic evaporites. The brackish waters have Cl contents of up to 2025 mg L−1 , and the ratios between dissolved ions and Cl, with the exception of the Br / Cl ratio, are not those expected on the basis of simple mixing between rainwater and seawater. The δ18O and δD data indicate that most of the waters fall between the regional meteoric water line and the global meteoric water line, supporting the

  15. Tracing groundwater salinization processes in coastal aquifers: a hydrogeochemical and isotopic approach in Na-Cl brackish waters of north-western Sardinia, Italy

    Directory of Open Access Journals (Sweden)

    G. Mongelli

    2013-01-01

    Full Text Available In the Mediterranean area the demand of good quality water is often threatened by salinization, especially in coastal areas. The salinization is the result of concomitant processes due to both marine water intrusion and rock-water interaction, which in some cases are hardly distinguishable. In northwestern Sardinia, in the Nurra area, salinization due to marine water intrusion has been recently evidenced as consequence of bore hole exploitation. However, the geology of the Nurra records a long history from Paleozoic to Quaternary, resulting in relative structural complexity and in a wide variety of lithologies, including Triassic evaporites. To elucidate the origin of the saline component in the Nurra aquifer, may furnish a useful and more general model for the salinization processes in the Mediterranean area, where the occurrence of evaporitic rocks in coastal aquifers is a common feature. In addition, due to intensive human activities and recent climatic changes, the Nurra has become vulnerable to desertification and, similarly to other Mediterranean islands, surface-water resources can periodically suffer from drastic shortage.

    With this in mind we report new data, regarding brackish waters of Na-Cl type of the Nurra, including major ions and selected trace elements (B, Br, I and Sr and isotopic data, including δ18O, δD in water, and δ34S and δ18O in dissolved sulphate. To better depict the origin of the salinity we also analyzed a set of Nurra Triassic evaporites for mineralogical and isotopic composition. The brackish waters have Cl contents up to 2025 mg L−1 and the ratios between dissolved ions and chlorine, with the exception of the Br/Cl ratio, are not those expected on the basis of a simple mixing between rain water and seawater.

    The δ18O and δD data indicate that most of the waters are within the Regional Meteoric Water Line and the Global Meteoric Water

  16. Production of cosmogenic isotopes 7Be, 10Be, 14C, 22Na, and 36Cl in the atmosphere: Altitudinal profiles of yield functions

    Science.gov (United States)

    Poluianov, S. V.; Kovaltsov, G. A.; Mishev, A. L.; Usoskin, I. G.

    2016-07-01

    New consistent and precise computations of the production of five cosmogenic radioisotopes, 7Be, 10Be, 14C, 22Na, and 36Cl, in the Earth's atmosphere by cosmic rays are presented in the form of tabulated yield functions. For the first time, a detailed set of the altitude profiles of the production functions is provided which makes it possible to apply the results directly as input for atmospheric transport models. Good agreement with most of the earlier published works for columnar and global isotopic production rates is shown. Altitude profiles of the production are important, in particular for such tasks as studies of strong solar particle events in the past, precise reconstructions of solar activity on long-term scale, tracing air mass dynamics using cosmogenic radioisotopes, etc. As an example, computations of the 10Be deposition flux in the polar region are shown for the last decades and also for a period around 780 A.D. and confronted with the actual measurements in Greenland and Antarctic ice cores.

  17. CAESAR-A high-efficiency CsI(Na) scintillator array for in-beam {gamma}-ray spectroscopy with fast rare-isotope beams

    Energy Technology Data Exchange (ETDEWEB)

    Weisshaar, D., E-mail: weisshaa@nscl.msu.ed [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Gade, A.; Glasmacher, T. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Grinyer, G.F.; Bazin, D.; Adrich, P. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Baugher, T.; Cook, J.M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Diget, C.A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); McDaniel, S.; Ratkiewicz, A.; Siwek, K.P.; Walsh, K.A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2010-12-21

    We report on the construction and commissioning of the high-efficiency CAESium-iodide scintillator ARray CAESAR, a device designed for in-beam {gamma}-ray spectroscopy experiments utilizing fast beams of rare isotopes at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). CAESAR consists of 192 CsI(Na) crystals, totaling 290 kg of active scintillator material. For 1 MeV {gamma} rays, a full-energy-peak efficiency of 35% is achieved at an in-beam energy resolution of better than 10% FWHM after event-by-event Doppler reconstruction of the {gamma} rays emitted by nuclei moving with velocities of v/c{approx}0.3-0.4. The spectral quality of the array allows for the identification of {gamma}-ray transitions with intensities of several 10 counts in the full-energy peak and thus opens new avenues for the study of the most exotic nuclei available at the NSCL for in-beam spectroscopy.

  18. Força de mordida em crianças com mantenedor de espaço funcional na fase da dentadura mista inicial Bite force in children with functional space maintainer in early mixed dentition

    Directory of Open Access Journals (Sweden)

    Suzane Rodrigues Jacinto-Gonçalves

    2009-08-01

    Full Text Available OBJETIVO: verificar a influência do mantenedor de espaço funcional (MEF na força muscular em crianças com perda prematura de molares decíduos na fase inicial da dentadura mista (5,5 a 6,5 anos de idade com oclusão normal, considerando-se o padrão facial. MÉTODOS: a amostra foi constituída por dois grupos: Grupo MEF (n = 15, com perda precoce de pelo menos um molar decíduo; e Grupo Controle (n = 16. Determinou-se a força de mordida máxima (FM com um tubo transmissor pressurizado, conectado a um circuito eletrônico analógico/digital antes (t0, um mês (t1 e 6 meses (t6 após a instalação do mantenedor. O padrão facial foi determinado pelo índice de Jarabak (FHR. Os dados foram analisados pela estatística descritiva, análise de variância para medidas repetidas, teste t e correlação de Pearson. RESULTADOS:a FM foi significativamente menor em t0 e t1 para o Grupo MEF em relação ao Controle. Em t6 não houve diferença. Os dois grupos apresentaram a FM significativamente maior em t6, em relação a t0, mas o percentual de variação para o Grupo MEF foi significativamente maior. Os valores de FHR não se correlacionaram com a FM, não ocorrendo diferença entre os tipos faciais intragrupos. Os dolicofaciais do Grupo MEF apresentaram a FM significativamente menor que os do Grupo Controle, em t0 e t1, mas não em t6. CONCLUSÃO: o maior aumento na FM para o Grupo MEF após 6 meses foi favorecido pelo maior número de contatos oclusais, devido aos dentes artificiais, melhorando a função e recuperando a força muscular.AIM: To verify the influence of a functional space maintainer (FSM in muscle strength in children with premature loss of primary molars in early mixed dentition (5.5-6.5 years old with normal occlusion, considering the facial pattern. METHODS: The sample was distributed in: FSM Group (n = 15, with premature loss of at least one primary molar and a Control Group (n = 16. It was determined the maximal bite force (BF

  19. Hydrodynamic characterization of fractured aquifers from Pocos de Caldas and adjacent areas using groundwater environmental radioactive isotopes; Caracterizacao hidrodinamica do meio aquifero fraturado na area de Pocos de Caldas e adjacencias, mediante a analise do conteudo radioisotopico das aguas subterraneas

    Energy Technology Data Exchange (ETDEWEB)

    Scudino, Paulo Cyro Baptista

    1992-04-01

    The geothermal system of Pocos de Caldas belongs to a complex volcanic system of fractured alkaline rocks. High geothermal gradients and natural occurences of two thermal springs furnishes a total yield of about 18m{sup 3}/h, within a temperature range of 40 to 44{sup 0}C. Aiming at establishing a functional model for the fractures aquifers of this specific system, the {sup 3} H and {sup 14} C radioisotopes were employed with complementary informations from the stable isotopes {sup 13} C, {sup 18} O and {sup 2} H. Furthermore structural-geological, geochemical hydrological, hydrochemical, and geothermal data were also introduced for evaluation. Three aquifer zones were identified: a shallow zone, where oxidizing environment is predominant, the water has a low mineralization, high CO{sub 2}, neutral pH, transit time in the range of 1 to 10 years. Relatively high concentration of {sup 18} O and {sup 2} H isotopes reflects at the present time the precipitation composition. The groundwater from the intermediate aquifer zone lies between 100 and 200m. Its age is in the range of 60 to 3,850 years and its chemical and isotopic compositions suggest a mix of different fraction with deep circulation of groundwater. The thermal water, from the deep zone, represents the final process related to chemical and isotopic groundwater evolution, and it comes from past precipitations, with low contents of {sup 18} O and {sup 2} H. It can be easily distinguished from the waters of the shallow zone due to its reducing conditions, a transit time around 12,500 years, HCO{sub 3}, Na{sup +}, SO{sup 2-}{sub 4} and silica high concentrations, together with F{sup -}, high pH and a quite rich {sup 18} O content when compared with its original composition. (author). 90 refs., 19 figs., 15 tabs.

  20. Redução do nível de proteína bruta em rações para frangos de corte em ambiente de termoneutralidade Dietary crude protein level reduction for broilers maintained in thermoneutral environment

    Directory of Open Access Journals (Sweden)

    Will Pereira de Oliveira

    2011-08-01

    Full Text Available O experimento foi realizado para avaliar o efeito da redução do nível de proteína bruta (PB da ração formulada de acordo com o conceito de proteína ideal e suplementada com aminoácidos industriais, sobre o desempenho e rendimento de cortes de frangos de corte machos de 22 a 42 dias de idade mantidos em ambiente termoneutro. Foram utilizados 280 frangos de corte machos "Cobb" com peso inicial de 856 ± 6,48 g, distribuídos em delineamento experimental inteiramente casualizado, com cinco tratamentos (21,6; 20,6; 19,6; 18,6 e 17,6% de PB, oito repetições de sete aves por unidade experimental. A temperatura no interior da sala foi mantida em 21,6 ± 0,7ºC, a umidade relativa em 74 ± 4,0% e a temperatura de globo negro em 22,5 ± 0,7ºC. O índice de temperatura de globo e umidade (ITGU calculado para o período foi de 70 ± 0,9. Não houve efeito da redução dos níveis de PB sobre o ganho de peso e o consumo de ração, entretanto, a conversão alimentar foi influenciada pela redução dos níveis de PB sendo que as aves alimentadas com a ração que continha 22,0% de PB apresentaram o melhor resultado. A redução dos níveis de PB não influenciou o peso absoluto de carcaça e os pesos absoluto e relativo de peito, coxa e sobrecoxa. A redução do nível de PB da ração, de 21,6 para 17,6%, e formulada de acordo com o conceito de proteína ideal piora a conversão alimentar dos frangos de corte mantidos em ambiente termoneutro, não influenciando as demais variáveis estudadas.The objective of this experiment was to evaluate the effects of dietary crude protein (CP level reduction of ration formulated according to ideal protein concept and with supplementation of industrial amino acids on the performance and yield of noble cuts of broilers from 22 to 42 days of age kept under thermoneutral conditions. It was used 280 "Cobb" male broilers with initial weight of 856 ± 6.48 g, distributed in a completely randomized experimental

  1. Anhydrite Solubility and Ca Isotope Fractionation in the Vapor-Liquid Field of the NaCl-H2O System: Implications for Hydrothermal Vent Fluids at Mid-ocean Ridges

    Science.gov (United States)

    Scheuermann, P.; Syverson, D. D.; Higgins, J. A.; Seyfried, W. E., Jr.

    2015-12-01

    Hydrothermal experiments were performed at 410, 420 and 450°C between 180-450 bar to investigate anhydrite (CaSO4) solubility and Ca isotope fractionation in the liquid-vapor stability field of the NaCl-H2O system. Experiments were conducted in flexible gold reaction cells and a fixed volume Ti reactor to reach all pressures between the critical curve and three-phase boundary. During isothermal decompression at 410°C, anhydrite solubility in the liquid phase increases (1 to 9 mmol/kg Ca), whereas the solubility decreases in the vapor phase (130 to systems with implications for mass transfer reactions at/near the magma-hydrothermal boundary at mid-ocean ridges.

  2. Carbon isotope analysis of dissolved organic carbon in fresh and saline (NaCl) water via continuous flow cavity ring-down spectroscopy following wet chemical oxidation.

    Science.gov (United States)

    Conaway, Christopher H; Thomas, Burt; Saad, Nabil; Thordsen, James J; Kharaka, Yousif K

    2015-01-01

    This work examines the performance and limitations of a wet chemical oxidation carbon analyser interfaced with a cavity ring-down spectrometer (WCO-CRDS) in a continuous flow (CF) configuration for measuring δ(13)C of dissolved organic carbon (δ(13)C-DOC) in natural water samples. Low-chloride matrix (oxidation despite using high-concentration oxidant, extended reaction time, or post-wet chemical oxidation gas-phase combustion. However, through a combination of dilution, chloride removal, and increasing the oxidant:sample ratio, high-salinity samples with sufficient DOC (>22.5 µg C/aliquot) may be analysed. The WCO-CRDS approach requires more total carbon (µg C/aliquot) than conventional CF-isotope ratio mass spectrometer, but is nonetheless applicable to a wide range of DOC concentration and water types, including brackish water, produced water, and basinal brines.

  3. Ergonomics Contribution in Maintainability

    Science.gov (United States)

    Teymourian, Kiumars; Seneviratne, Dammika; Galar, Diego

    2017-09-01

    The objective of this paper is to describe an ergonomics contribution in maintainability. The economical designs, inputs and training helps to increase the maintainability indicators for industrial devices. This analysis can be helpful, among other cases, to compare systems, to achieve a better design regarding maintainability requirements, to improve this maintainability under specific industrial environment and to foresee maintainability problems due to eventual changes in a device operation conditions. With this purpose, this work first introduces the notion of ergonomics and human factors, maintainability and the implementation of assessment of human postures, including some important postures to perform maintenance activities. A simulation approach is used to identify the critical posture of the maintenance personnel and implements the defined postures with minimal loads on the personnel who use the equipment in a practical scenario. The simulation inputs are given to the designers to improve the workplace/equipment in order to high level of maintainability. Finally, the work concludes summarizing the more significant aspects and suggesting future research.

  4. Maintaining Learners’Motivation

    Institute of Scientific and Technical Information of China (English)

    SI Zi-han

    2015-01-01

    Foreign language learning is a complex process and its success is determined by a variety of factors. The prime one of them is motivation ,which, as everyone knows, could be controlled by external forces so as to be taken advantage of. Motivation could prompt the learner to have his own learning goals and let him finish his learning task autonomously. All of that shows the im⁃portance of maintaining learners’motivation. This paper will demonstrate not only the definition and the types of motivation, but al⁃so the methods that could be used to stimulate and maintain the motivation.

  5. Economy Maintains Good Health

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    China’s national economy has maintained rapid even growth in the first half of 2007, according to Xie Fuzhan, Commissioner of the National Bureau of Statistics. He was referring to major economic indicators of the January-June period that reveal that Chi

  6. Maintaining cell identity

    DEFF Research Database (Denmark)

    Comet, Itys; Riising, Eva M; Leblanc, Benjamin

    2016-01-01

    trials. Several observations show that PRC2 can have both oncogenic and tumour-suppressive functions. We propose that these apparently opposing roles of PRC2 in cancer are a consequence of the molecular function of the complex in maintaining, rather than specifying, the transcriptional repression state...

  7. Crustal evolution of South American Platform based on Sm-Nd isotope geochemistry; Evolucao crustal da plataforma sul americana com base na geoquimica isotopica Sm-Nd

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kei

    1998-07-01

    Sm-Nd isotopic systematics is relevant to the topics of origin and evolution the of continental crust, where model ages refer to the time when crustal material was differentiated from the upper mantle. Alternative interpretations are due to a lack of adequate information on crustal processes and the variable composition of the mantle sources. The Sm-Nd methods are presented, and applied on rock materials from the South American Platform. The main conclusions indicate juvenile accretion with higher growth rates (peaks), around 3.7-3.5 Ga ({approx} 0.5% in volume), 3.1 - 2.9 Ga ({approx}16%), 2.7 - 2.6 ({approx} 9%), 2.2 - 1.9 (35%) and 1.3-1.0 (7%). The continental growth curve indicates that about 35 % of the crust was formed by 2.5 Ga, 88% by 1.8 Ga and 99% by 1.0 Ga, and the remaining {approx} 1 % was added in the Phanerozoic. Rapid crustal growth occurred between 2.2 and 1.9 Ga. The main period of continental crust formation occurred during the Paleoproterozoic, corresponding to 54 % in volume. Sm-Nd model ages, when compared with the crystallisation ages of granitoid rocks, furnish a rough estimate of juvenile vs. reworked material. Within the South American Platform about 45% of juvenile continental crust is still preserved within tectonic provinces of different ages. The remainder represents continental crust reworked in younger tectono-thermal events. In particular crustal reworking was predominating over juvenile accretion during Meso-Neoproterozoic. The Transbrasiliano Lineament is a megasuture, active in the Neoproterozoic, which separates a large northwestern mass, including the Amazonian and Sao Luis Cratons, from a southeastern mass, formed by a collage of cratonic fragments, of which the Sao Francisco and Rio de La Plata are the largest. The crustal evolutions of these two large continental masses are considered individually, and can be resumed following form: I - Old Archean rocks (>3.4 Ga) are found only within the south-eastern part (Gaviao Block

  8. Nuclear power plant maintainability.

    Science.gov (United States)

    Seminara, J L; Parsons, S O

    1982-09-01

    In the mid-1970s a general awareness of human factors engineering deficiencies associated with power plant control rooms took shape and the Electric Power Research Institute (EPRI) awarded the Lockheed Corporation a contract to review the human factors aspects of five representative operational control rooms and their associated simulators. This investigation revealed a host of major and minor deficiencies that assumed unforeseen dimensions in the post- Three Mile Island accident period. In the course of examining operational problems (Seminara et al, 1976) and subsequently the methods for overcoming such problems (Seminara et al, 1979, 1980) indications surfaced that power plants were far from ideal in meeting the needs of maintenance personnel. Accordingly, EPRI sponsored an investigation of the human factors aspects of power plant maintainability (Seminara, 1981). This paper provides an overview of the maintainability problems and issues encountered in the course of reviewing five nuclear power plants.

  9. Direct bonded space maintainers.

    Science.gov (United States)

    Santos, V L; Almeida, M A; Mello, H S; Keith, O

    1993-01-01

    The aim of this study was to evaluate clinically a bonded space maintainer, which would reduce chair-side time and cost. Sixty appliances were fabricated from 0.7 mm stainless steel round wire and bonded using light-cured composite to the two teeth adjacent to the site of extraction of a posterior primary tooth. Twenty males and sixteen females (age range 5-9-years-old) were selected from the Pedodontic clinic of the State University of Rio de Janeiro. The sixty space maintainers were divided into two groups according to the site in which they were placed: a) absent first primary molar and b) absent second primary molar. Impressions and study models were obtained prior to and 6 months after bonding the appliances. During this period only 8.3% of failures were observed, most of them from occlusal or facial trauma. Student t-test did not show statistically significant alterations in the sizes of the maintained spaces during the trial period.

  10. A SNARE-like superfamily protein SbSLSP from the halophyte Salicornia brachiata confers salt and drought tolerance by maintaining membrane stability, K+/Na+ ratio, and antioxidant machinery

    Directory of Open Access Journals (Sweden)

    Dinkar eSingh

    2016-06-01

    Full Text Available About 1000 salt-responsive ESTs were identified from an extreme halophyte Salicornia brachiata. Among these, a novel salt-inducible gene SbSLSP, (Salicornia brachiata SNARE-like superfamily protein showed up-regulation upon salinity and dehydration stress. The presence of cis-regulatory motifs related to abiotic stress in the putative promoter region supports our finding that SbSLSP gene is inducible by abiotic stress. The SbSLSP protein showed a high sequence identity to hypothetical/uncharacterised proteins from Beta vulgaris, Spinacia oleracea, Eucalyptus grandis and Prunus persica and with SNARE-like superfamily proteins from Zostera marina and Arabidopsis thaliana. Bioinformatics analysis predicted a clathrin adaptor complex small-chain domain and N-myristoylation site in the SbSLSP protein. Subcellular localisation studies indicated that the SbSLSP protein is mainly localised in the plasma membrane. Using transgenic tobacco lines, we establish that overexpression of SbSLSP resulted in elevated tolerance to salt and drought stress. The improved tolerance was confirmed by alterations in a range of physiological parameters, including high germination and survival rate, higher leaf chlorophyll contents, and reduced accumulation of Na+ ion and reactive oxygen species (ROS. Furthermore, overexpressing lines also showed lower water loss, higher cell membrane stability and increased accumulation of proline and ROS-scavenging enzymes. Overexpression of SbSLSP also enhanced the transcript levels of ROS-scavenging and signalling enzyme genes. This study is the first investigation of the function of the SbSLSP gene as a novel determinant of salinity/drought tolerance. The results suggest that SbSLSP could be a potential candidate to increase salinity and drought tolerance in crop plants for sustainable agriculture in semi-arid saline soil.

  11. A SNARE-Like Superfamily Protein SbSLSP from the Halophyte Salicornia brachiata Confers Salt and Drought Tolerance by Maintaining Membrane Stability, K(+)/Na(+) Ratio, and Antioxidant Machinery.

    Science.gov (United States)

    Singh, Dinkar; Yadav, Narendra Singh; Tiwari, Vivekanand; Agarwal, Pradeep K; Jha, Bhavanath

    2016-01-01

    About 1000 salt-responsive ESTs were identified from an extreme halophyte Salicornia brachiata. Among these, a novel salt-inducible gene SbSLSP (Salicornia brachiata SNARE-like superfamily protein), showed up-regulation upon salinity and dehydration stress. The presence of cis-regulatory motifs related to abiotic stress in the putative promoter region supports our finding that SbSLSP gene is inducible by abiotic stress. The SbSLSP protein showed a high sequence identity to hypothetical/uncharacterized proteins from Beta vulgaris, Spinacia oleracea, Eucalyptus grandis, and Prunus persica and with SNARE-like superfamily proteins from Zostera marina and Arabidopsis thaliana. Bioinformatics analysis predicted a clathrin adaptor complex small-chain domain and N-myristoylation site in the SbSLSP protein. Subcellular localization studies indicated that the SbSLSP protein is mainly localized in the plasma membrane. Using transgenic tobacco lines, we establish that overexpression of SbSLSP resulted in elevated tolerance to salt and drought stress. The improved tolerance was confirmed by alterations in a range of physiological parameters, including high germination and survival rate, higher leaf chlorophyll contents, and reduced accumulation of Na(+) ion and reactive oxygen species (ROS). Furthermore, overexpressing lines also showed lower water loss, higher cell membrane stability, and increased accumulation of proline and ROS-scavenging enzymes. Overexpression of SbSLSP also enhanced the transcript levels of ROS-scavenging and signaling enzyme genes. This study is the first investigation of the function of the SbSLSP gene as a novel determinant of salinity/drought tolerance. The results suggest that SbSLSP could be a potential candidate to increase salinity and drought tolerance in crop plants for sustainable agriculture in semi-arid saline soil.

  12. A SNARE-Like Superfamily Protein SbSLSP from the Halophyte Salicornia brachiata Confers Salt and Drought Tolerance by Maintaining Membrane Stability, K+/Na+ Ratio, and Antioxidant Machinery

    Science.gov (United States)

    Singh, Dinkar; Yadav, Narendra Singh; Tiwari, Vivekanand; Agarwal, Pradeep K.; Jha, Bhavanath

    2016-01-01

    About 1000 salt-responsive ESTs were identified from an extreme halophyte Salicornia brachiata. Among these, a novel salt-inducible gene SbSLSP (Salicornia brachiata SNARE-like superfamily protein), showed up-regulation upon salinity and dehydration stress. The presence of cis-regulatory motifs related to abiotic stress in the putative promoter region supports our finding that SbSLSP gene is inducible by abiotic stress. The SbSLSP protein showed a high sequence identity to hypothetical/uncharacterized proteins from Beta vulgaris, Spinacia oleracea, Eucalyptus grandis, and Prunus persica and with SNARE-like superfamily proteins from Zostera marina and Arabidopsis thaliana. Bioinformatics analysis predicted a clathrin adaptor complex small-chain domain and N-myristoylation site in the SbSLSP protein. Subcellular localization studies indicated that the SbSLSP protein is mainly localized in the plasma membrane. Using transgenic tobacco lines, we establish that overexpression of SbSLSP resulted in elevated tolerance to salt and drought stress. The improved tolerance was confirmed by alterations in a range of physiological parameters, including high germination and survival rate, higher leaf chlorophyll contents, and reduced accumulation of Na+ ion and reactive oxygen species (ROS). Furthermore, overexpressing lines also showed lower water loss, higher cell membrane stability, and increased accumulation of proline and ROS-scavenging enzymes. Overexpression of SbSLSP also enhanced the transcript levels of ROS-scavenging and signaling enzyme genes. This study is the first investigation of the function of the SbSLSP gene as a novel determinant of salinity/drought tolerance. The results suggest that SbSLSP could be a potential candidate to increase salinity and drought tolerance in crop plants for sustainable agriculture in semi-arid saline soil. PMID:27313584

  13. Leatherback Isotopes

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — SWFSC is currently working on a project identifying global marine isotopes using leatherback turtles (Dermochelys coriacea) as the indicator species. We currently...

  14. Isotopic chirality

    Energy Technology Data Exchange (ETDEWEB)

    Floss, H.G. [Univ. of Washington, Seattle, WA (United States)

    1994-12-01

    This paper deals with compounds that are chiral-at least in part, due to isotope substitution-and their use in tracing the steric course of enzyme reaction in vitro and in vivo. There are other applications of isotopically chiral compounds (for example, in analyzing the steric course of nonenzymatic reactions and in probing the conformation of biomolecules) that are important but they will not be discussed in this context.

  15. Isotopic Paleoclimatology

    Science.gov (United States)

    Bowen, R.

    Paleotemperature scales were calculated by H. C. Urey and others in the 1950s to assess past temperatures, and later work using the stable isotopes of oxygen, hydrogen, and carbon employed standards such as Peedee belemnite (PDB) and Standard Mean Ocean Water (SMOW). Subsequently, subjects as diverse as ice volume and paleotemperatures, oceanic ice and sediment cores, Pleistocene/Holocene climatic changes, and isotope chronostratigraphy extending back to the Precambrian were investigated.

  16. Efeitos de extratos de plantas na biologia de Spodoptera frugiperda (J. E. Smith, 1797 (Lepidoptera: Noctuidae mantida em dieta artificial Effects of plant extracts on the biology of Spodoptera frugiperda (J. E. Smith, 1797 (Lepidoptera: Noctuidae maintained under artificial diet

    Directory of Open Access Journals (Sweden)

    Gilberto Pedreira Santiago

    2008-06-01

    Full Text Available Avaliaram-se os efeitos dos extratos aquosos a 10% de folhas e ramos de arruda (Ruta graveolens L., folhas e ramos de melão-de-são-caetano (Momordica charantia L., folhas do alecrim-pimenta (Lippia sidoides Cham. e fruto verde de mamona (Ricinus communis L., sobre a biologia da lagarta-do-cartucho do milho (Spodoptera frugiperda, mantida em dieta artificial. Os parâmetros avaliados foram duração e viabilidade das fases larval e pupal, peso de pupa, fecundidade, fertilidade e longevidade de adultos. Larvas de S. frugiperda recém-eclodidas foram colocadas em tubos de ensaio com dieta artificial, contendo os extratos de cada material testado. O extrato aquoso do fruto verde de R. communis apresentou bioatividade, nos parâmetros duração larval e pupal e peso de pupa. O extrato aquoso de R. graveolens reduziu o peso de pupa. A dieta contendo extrato de folhas e ramos de M. charantia reduziu a viabilidade larval e o peso de pupa. O extrato aquoso de folhas de L. sidoides não afetou as fases larval e pupal, reduziu a postura e a viabilidade de ovos e aumentou a longevidade de adultos de S. frugiperda. A viabilidade de pupa não foi afetada pelos extratos testados.The effects of aqueous extracts, at 10% concentration of leaves and branches of Ruta graveolens L., leaves and branches of Momordica charantia L., leaves of Lippia sidoides Cham. and green fruits of Ricinus communis L. were evaluated on the biology of fall armyworm (Spodoptera frugiperda maintained under artificial diet. The evaluated parameters were: duration and viability of the larval and pupal phases, pupa weight, fecundity, fertility and longevity of adults. Just-hatched larvae of S. frugiperda was placed in test tube with artificial diet containing extracts of each tested material. The aqueous extract of the green fruits of R. communis presented bioactivity upon duration and weight of larval and pupal phases. The aqueous extract of R. graveolens reduced weight of pupa. The diet

  17. Redução da proteína bruta da ração para suínos machos castrados dos 15 aos 30 kg mantidos em termoneutralidade Reduction of crude protein level of ration to castrated swine from 15 to 30 kg maintained in a termoneutral environment (22ºC

    Directory of Open Access Journals (Sweden)

    Rony Antonio Ferreira

    2003-12-01

    Full Text Available Um experimento foi conduzido para avaliar a influência da redução da proteína bruta (PB e suplementação de aminoácidos sintéticos sobre o desempenho de suínos machos castrados mantidos em ambiente termoneutro (22ºC. Foram utilizados 60 leitões mestiços (Landrace x Large White com peso médio inicial de 15,0 kg e idade média de 53,1 dias, em delineamento inteiramente ao acaso, com cinco tratamentos (18, 17, 16, 15 e 14% PB, seis repetições e dois animais por unidade experimental. As rações experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram o peso médio de 30,2 kg. A temperatura média no interior da sala foi mantida em 22ºC, com umidade relativa de 82,3%. O Índice de Temperatura de Globo e Umidade calculado no período foi de 69,6. Não se observou efeito da redução do nível de proteína bruta da ração sobre as variáveis de desempenho (consumo de ração, ganho de peso e conversão alimentar. As taxas de deposição de proteína e gordura também não foram influenciadas pela redução da PB na ração. Os tratamentos influenciaram os pesos absoluto e relativo do estômago e o peso absoluto do intestino, sendo os maiores valores observados em animais que receberam a ração com maior nível de proteína bruta. Concluiu-se que o nível de PB da ração pode ser reduzido de 18 para 14%, sem prejudicar o desempenho de suínos machos dos 15 aos 30 kg mantidos em ambiente termoneutro, desde que devidamente suplementadas com aminoácidos essenciais limitantes.One experiment was conducted to evaluate the influence of reduction of the crude protein (CP level of ration with amino acid supplementation on performance of castrated males swines maintained in a termoneutral environment (22ºC. A total of sixty crossbred swines (Landrace x Large White, with average initial weight of 15.0 kg and 53.1 days old, was allotted to a completely randomized design with five treatments (18, 17, 16

  18. Maintaining Web Cache Coherency

    Directory of Open Access Journals (Sweden)

    2000-01-01

    Full Text Available Document coherency is a challenging problem for Web caching. Once the documents are cached throughout the Internet, it is often difficult to keep them coherent with the origin document without generating a new traffic that could increase the traffic on the international backbone and overload the popular servers. Several solutions have been proposed to solve this problem, among them two categories have been widely discussed: the strong document coherency and the weak document coherency. The cost and the efficiency of the two categories are still a controversial issue, while in some studies the strong coherency is far too expensive to be used in the Web context, in other studies it could be maintained at a low cost. The accuracy of these analysis is depending very much on how the document updating process is approximated. In this study, we compare some of the coherence methods proposed for Web caching. Among other points, we study the side effects of these methods on the Internet traffic. The ultimate goal is to study the cache behavior under several conditions, which will cover some of the factors that play an important role in the Web cache performance evaluation and quantify their impact on the simulation accuracy. The results presented in this study show indeed some differences in the outcome of the simulation of a Web cache depending on the workload being used, and the probability distribution used to approximate updates on the cached documents. Each experiment shows two case studies that outline the impact of the considered parameter on the performance of the cache.

  19. Níveis de proteína bruta e suplementação de aminoácidos em rações para leitoas dos 30 aos 60 kg mantidas em ambiente de alta temperatura Dietary crude protein levels and amino acid supplementation for gilts from 30 to 60 kg maintained in a high environmental temperature

    Directory of Open Access Journals (Sweden)

    Uislei Antonio Dias Orlando

    2007-10-01

    Full Text Available Foi realizado um estudo para avaliar níveis de proteína bruta (PB e suplementação de aminoácidos em rações para leitoas mantidas em ambiente de alta temperatura (temperatura do ar de 30ºC, umidade relativa de 66,1% e ITGU calculado de 79,7 na fase de crescimento. Foram utilizadas 50 leitoas mestiças (Landrace ´ Large White com peso inicial médio de 30,2 kg, em delineamento experimental inteiramente ao acaso, com cinco tratamentos e cinco repetições de dois animais por unidade experimental. Os tratamentos consistiram de cinco níveis de PB (19, 18, 17, 16 e 15% na ração e da suplementação com lisina, metionina, triptofano, treonina e valina para manutenção da mesma qualidade protéica da ração. As rações experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram o peso médio de 60,1 kg. Não se observou efeito do nível de proteína bruta da ração sobre o desempenho dos animais (consumo de ração, ganho de peso e conversão alimentar. A deposição de proteína na carcaça também não foi influenciada pela redução do nível de PB da ração, pois os animais alimentados com a ração com 18% de PB apresentaram os maiores valores. Os níveis de PB na ração não influenciaram os pesos absoluto e relativo dos órgãos dos animais. O nível de PB da ração pode ser reduzido em até 4% (de 19 para 15% de PB, pois essa redução não altera o desempenho de leitoas mantidas em ambiente de alta temperatura na fase dos 30 aos 60 kg, desde que as rações sejam devidamente suplementadas com todos os aminoácidos essenciais.An experiment was conduced to evaluate crude protein (CP levels and amino acid supplementation for gilts from 30 to 60 kg maintained in a high environmental temperature (air temperature of 30ºC; relative humidity of 66.1% and BGHI of 79.7. Fifty crossbreed gilts (Landrace X Large White with an average initial weight of 30.2 kg were allotted to a randomized

  20. Modified bonded bridge space maintainer.

    Science.gov (United States)

    Liegeois, F; Limme, M

    1999-01-01

    The premature loss of primary teeth can create the need for space maintenance and restoration of function. This article presents a fixed bonded space maintainer, which allows space to be maintained with economy of dental tissues.

  1. Assessing optimal software architecture maintainability

    NARCIS (Netherlands)

    Bosch, Jan; Bengtsson, P.O.; Smedinga, Rein; Sousa, P; Ebert, J

    2000-01-01

    Over the last decade, several authors have studied the maintainability of software architectures. In particular, the assessment of maintainability has received attention. However, even when one has a quantitative assessment of the maintainability of a software architecture, one still does not have

  2. Assessing optimal software architecture maintainability

    NARCIS (Netherlands)

    Bosch, Jan; Bengtsson, P.O.; Smedinga, Rein; Sousa, P; Ebert, J

    2000-01-01

    Over the last decade, several authors have studied the maintainability of software architectures. In particular, the assessment of maintainability has received attention. However, even when one has a quantitative assessment of the maintainability of a software architecture, one still does not have a

  3. Handbook of environmental isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Baskaran, Mark (ed.) [Wayne State Univ., Detroit, MI (United States). Dept. Geology

    2011-07-01

    Applications of radioactive and stable isotopes have revolutionized our understanding of the Earth and near-earth surface processes. The utility of the isotopes are ever-increasing and our sole focus is to bring out the applications of these isotopes as tracers and chronometers to a wider audience so that they can be used as powerful tools to solve environmental problems. New developments in this field remain mostly in peer-reviewed journal articles and hence our goal is to synthesize these findings for easy reference for students, faculty, regulators in governmental and non-governmental agencies, and environmental companies. While this volume maintains its rigor in terms of its depth of knowledge and quantitative information, it contains the breadth needed for wide variety problems and applications in the environmental sciences. This volume presents all of the newer and older applications of isotopes pertaining to the environmental problems in one place that is readily accessible to readers. This book not only has the depth and rigor that is needed for academia, but it has the breadth and case studies to illustrate the utility of the isotopes in a wide variety of environments (atmosphere, oceans, lakes, rivers and streams, terrestrial environments, and sub-surface environments) and serves a large audience, from students and researchers, regulators in federal, state and local governments, and environmental companies. (orig.)

  4. Isotopic Discrimination of Some Solutes in Liquid Ammonia

    Science.gov (United States)

    Taube, H.; Viste, A.

    1966-01-01

    The nitrogen isotopic discrimination of some salts and metals, studies in liquid ammonia solution at -50�C, decreases in magnitude in the order Pb{sup ++}, Ca{sup ++}, Li{sup +}, AG{sup +}, Na{sup +}, Li, K{sup +}, Na, K. The isotopic discrimination appears to provide qualitative information about the strength of the cation-solvent interaction in liquid ammonia.

  5. Use of the HRICP-MS technique for the evaluation of boron isotopes in Eucalitpus plants; Uso da tecnica HRICP-MS na avaliacao dos isotopos de boro em eucalipto

    Energy Technology Data Exchange (ETDEWEB)

    Mattiello, Edson Marcio; Ruiz, Hugo Alberto; Silva, Ivo Ribeiro da, E-mail: mattiello@ufv.b [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Solos; Sarkis, Jorge Eduardo de Souza [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The {sup 10}B isotope tracer technique is essential to study the B mobility in plants. Factors that can influence the quality of measured B isotope ratios were optimized experimentally using High Resolution Inductively Coupled Plasma Mass Spectrometry (HRICP-MS). An isotopically certified standard (NIST SRM-951) was used. The best combination was obtained using a resolution of 400, a RF power of 1250 W, followed by 15 measurements over a 10-s integration period each (15*10). Utilizing this approach it was possible to obtain a precision of 0.3 % in standard material and 2z % in the experimental samples. The results show the importance of establishing optimized work conditions before carrying out the analytical series. (author)

  6. Dificuldades enfrentadas pelos parceiros sorodiscordantes ao HIV na manutençao do sexo seguro Dificultades enfrentadas por las parejas serodiscordantes para el HIV en el mantenimiento del sexo seguro Difficulties faced by HIV mixed status couples in maintaining safe sex

    Directory of Open Access Journals (Sweden)

    Renata Karina Reis

    2005-02-01

    Full Text Available Neste estudo objetivou-se identificar os fatores que interferem na manutenção do sexo seguro entre parceiros com sorologias distintas para o HIV. Os dados foram coletados através de entrevistas individuais com 11 portadores do HIV/aids que convivem com parceria soronegativa ao HIV seguidos num ambulatório especializado no atendimento a aids e analisados com base na análise de Prosa de André (1983, utilizando o referencial teórico da vulnerabilidade ao HIV/aids. A prevenção sexual do HIV/aids para a parceria não infectada constitui num dos maiores desafios para os casais sorodiscordantes, visto que o condom tem diferente aceitação entre homens e mulheres. A maior motivação para o uso do preservativo entre casais sorodiscordantes não elimina as dificuldades na sua utilização para a manutenção do sexo seguro. Os casais sorodiscordantes merecem atendimento específico, e as estratégias preventivas devem contemplar os aspectos culturais e psicossociais que se constituem em importantes aspectos de vulnerabilidade dos parceiros soronegativos.La finalidad de este estudio fue identificar los factores que interfieren en el mantenimiento del sexo seguro. La recopilación de datos ocurrió mediante entrevistas individuales con 11 portadores del VIH/sida que conviven con pareja seronegativa para el VIH, seguidos en un ambulatorio especializado en la atención al SIDA. El análisis se hizo con base en el Análisis de prosa de André (1983. El concepto de la vulnerabilidad fue adoptado como referencial teórico. La prevención sexual de HIV/sida para la pareja no infectada se constituye en uno de los mayores desafíos para las parejas serodiscordantes, porque el condón tiene la aceptación diferente entre los hombres y mujeres. La motivación mayor para el uso del preservativo entre las parejas serodiscordante no elimina las dificultades en su uso para el mantenimiento del sexo seguro. Las parejas serodiscordantes merecen la atenci

  7. Níveis de proteína bruta e suplementação de aminoácidos em rações para leitoas mantidas em ambiente de conforto térmico dos 30 aos 60 kg Crude protein levels of ration with amino acid supplementation to gilts maintained in a thermal comfort environment from 30 to 60 kg

    Directory of Open Access Journals (Sweden)

    Uislei Antonio Dias Orlando

    2005-02-01

    Full Text Available Foi conduzido um experimento para determinar o nível de proteína bruta (PB das rações com suplementação de aminoácidos para leitoas mestiças (Landrace x Large White mantidas em ambiente de conforto térmico. Os animais (peso médio inicial de 30,1 kg foram distribuídos em delineamento experimental inteiramente ao acaso, com cinco tratamentos (19, 18, 17, 16 e 15% de PB com suplementação de lisina metionina, triptofano, treonina e valina, para se manter a mesma qualidade proteica, cinco repetições e dois animais por unidade experimental. As rações experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram peso médio de 60,3 kg. O nível de PB da ração influenciou o ganho de peso diário e a conversão alimentar, mas não influiu no consumo de ração diário. A deposição de proteína não variou entre os níveis de 19 e 16% de PB da ração, enquanto os animais que consumiram a ração com menor nível de PB (15% apresentaram o menor valor. Os tratamentos não influenciaram os pesos absoluto e relativo dos órgãos avaliados. Concluiu-se que o nível de PB da ração para leitoas dos 30 aos 60 kg mantidas em ambiente de conforto térmico pode ser reduzido de 19 para 15%, sem prejudicar o desempenho, desde que as rações sejam devidamente suplementada com os aminoácidos essenciais limitantes.An experiment was conduced to determine the crude protein (CP level in diets with amino acids supplementation for gilts maintained in a thermal comfort environment. Fifty crossbreed crossbred gilts (Landrace x Large White with initial average weight of 30.1 kg were allotted to a completely randomized experimental design, with five treatments (19, 18, 17, 16 and 15% of CP with supplementation of lysine, methionine, tryptophan, threonine and valine to maintain the same protein quality five replicates and two animals per experimental unit. The experimental rations were fed ad libitum until the end of

  8. Stable isotope studies

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs.

  9. A Novel Polarization Maintaining Fiber

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It introduces a novel elliptical jacket polarization maintaining fiber, whose SAP is like numeral "1". One preform can be drawn over 8km. Fiber's performances show that it is fit for fiber gyroscope and other sensors.

  10. A Novel Polarization Maintaining Fiber

    Institute of Scientific and Technical Information of China (English)

    Benjamin Xue

    2003-01-01

    It introduces a novel elliptical jacket polarization maintaining fiber, whose SAP is like numeral "1" One preform can be drawn over 8km. Fiber's performances show that it is fit for fiber gyroscope and other sensors.

  11. Simple fixed functional space maintainer.

    Science.gov (United States)

    Goenka, Puneet; Sarawgi, Aditi; Marwah, Nikhil; Gumber, Parvind; Dutta, Samir

    2014-01-01

    Premature loss of a primary tooth is one of the most common etiology for malocclusion. Space maintainers are employed to prevent this complication. In anterior region, esthetics is an important concern along with function and space management. Fiber-reinforced composite (FRC) retained space maintainer solves all these purposes ef ficiently and ef fectively. In addition, the technique is simple and the appliance is very comfortable inside the oral cavity. Here is a case of premature loss of anterior primary tooth which was replaced by FRC retained esthetic functional space maintainer. The appliance was found to be functioning satisfactorily inside the oral cavity till the last visit (1 Year). How to cite this article: Goenka P, Sarawgi A, Marwah N, Gumber P, Dutta S. Simple Fixed Functional Space Maintainer. Int J Clin Pediatr Dent 2014;7(3):225-228.

  12. Marshal: Maintaining Evolving Models Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SIFT proposes to design and develop the Marshal system, a mixed-initiative tool for maintaining task models over the course of evolving missions. Marshal-enabled...

  13. How to maintain improved cultivars

    NARCIS (Netherlands)

    Parlevliet, J.E.

    2007-01-01

    Improved cultivars loose their identity and healthiness unless maintained properly. Contaminating and degrading forces, such as outcrossing, volunteer plants, mixing, natural selection, mutation and seed-borne diseases, are at the root of this. Maintenance selection can prevent this deterioration.

  14. Simple Fixed Functional Space Maintainer

    OpenAIRE

    Goenka, Puneet; Sarawgi, Aditi; Marwah, Nikhil; Gumber, Parvind; Dutta, Samir

    2015-01-01

    ABSTRACT% Premature loss of a primary tooth is one of the most common etiology for malocclusion. Space maintainers are employed to prevent this complication. In anterior region, esthetics is an important concern along with function and space management. Fiber-reinforced composite (FRC) retained space maintainer solves all these purposes ef ficiently and ef fectively. In addition, the technique is simple and the appliance is very comfortable inside the oral cavity. Here is a case of premature ...

  15. Fluid inclusion and stable isotope study of telluride mineralization at Mahd Adh Dhahab, Saudi Arabia

    Energy Technology Data Exchange (ETDEWEB)

    Afifi, A.M.; Kelly, W.C.

    1985-01-01

    Mahd Adh Dhahab is unique among Precambrian gold deposits in that it displays many characteristics of epithermal precious metal districts. Au-Ag-Cu-Zn-Pb mineralization occurs principally in the third of five generations of quartz veins. Sulfur isotopic equilibrium was generally maintained among sulfides which range in delta/sup 34/S from -1.8 (galena) to 6.4 (pyrite). The narrow range in delta/sup 34/S of sulfides is inconsistent with large variations in f02 calculated from chlorite +/- pyrite +/- hematite assemblages. Galena-sphalerite pairs yield temperatures in the range 160-270/sup 0/C for stage 3 veins, which fall within the 120-300/sup 0/C range defined by fluid inclusion thermometry. Fluid salinities are in the range 0.5 wt.% NaCl equivalent. The trends indicate mixing of delta/sup 18/O approx. = 0 waters with heavier more oxidized waters during stage 4 deposition which led to non-equilibrium oxidation of H/sub 2/S. deltaD values of vein chlorites fall within a narrow range of -65 to -75, while deltaD measurements of inclusion fluids in quartz display a wider spread from -13 to -43; the lighter values may reflect contamination by secondary inclusions. The stable isotope data indicate probable derivation of both sulfur and carbon from igneous sources. District-wide variation in sulfur and oxygen isotopes indicate the presence of several hydrothermal centers, which has possible significance to exploration.

  16. Bulkloading and Maintaining XML Documents

    NARCIS (Netherlands)

    Schmidt, A.R.; Kersten, M.L.

    2002-01-01

    The popularity of XML as a exchange and storage format brings about massive amounts of documents to be stored, maintained and analyzed -- a challenge that traditionally has been tackled with Database Management Systems (DBMS). To open up the content of XML documents to analysis with declarative quer

  17. Identifying crucial parameter correlations maintaining bursting activity.

    Directory of Open Access Journals (Sweden)

    Anca Doloc-Mihu

    2014-06-01

    Full Text Available Recent experimental and computational studies suggest that linearly correlated sets of parameters (intrinsic and synaptic properties of neurons allow central pattern-generating networks to produce and maintain their rhythmic activity regardless of changing internal and external conditions. To determine the role of correlated conductances in the robust maintenance of functional bursting activity, we used our existing database of half-center oscillator (HCO model instances of the leech heartbeat CPG. From the database, we identified functional activity groups of burster (isolated neuron and half-center oscillator model instances and realistic subgroups of each that showed burst characteristics (principally period and spike frequency similar to the animal. To find linear correlations among the conductance parameters maintaining functional leech bursting activity, we applied Principal Component Analysis (PCA to each of these four groups. PCA identified a set of three maximal conductances (leak current, [Formula: see text]Leak; a persistent K current, [Formula: see text]K2; and of a persistent Na+ current, [Formula: see text]P that correlate linearly for the two groups of burster instances but not for the HCO groups. Visualizations of HCO instances in a reduced space suggested that there might be non-linear relationships between these parameters for these instances. Experimental studies have shown that period is a key attribute influenced by modulatory inputs and temperature variations in heart interneurons. Thus, we explored the sensitivity of period to changes in maximal conductances of [Formula: see text]Leak, [Formula: see text]K2, and [Formula: see text]P, and we found that for our realistic bursters the effect of these parameters on period could not be assessed because when varied individually bursting activity was not maintained.

  18. Isotopic characterization of metabasites and amphibolites of the Acungui and Setuva Groups at the southern portion of de Ribeira Belt; Caracterizacao isotopica de metabasitos e anfibolitos dos Grupos Acungui e Setuva na porcao sul da Faixa Ribeira

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcos Aurelio Farias de; Daitx, Elias Carneiro [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Dept. de Petrologia e Metalogenia; Maniesi, Vanderlei [Universidade Federal de Rondonia (UNIR), Porto Velho (Brazil); Teixeira, Wilson [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias. Centro de Pesquisas Geocronologicas

    2002-12-15

    Pb, Rb, Sr, Sm and Nd isotope analyses were carried out on amphibolitic rocks from Campo Largo (PR), Rio Branco do Sul (PR) and Adrianopolis (PR) and for the metabasite from Adrianopolis and Apiai (SP), all belonging to the Acungui and Setuva Groups, southern portion of the Ribeira Belt. These occurrences were chosen because each exhibits geochemical data indicative of a mantle source, having different signatures. Geochronologic determinations are available only for the Apiai metagabro with Neoproterozoic ages of 617 +- 4 Ma (U/Pb in zircon) and 839 +- 85 Ma (Rb/Sr, whole rock). Age determinations by Sm/Nd mineral isochron using whole rock, plagioclase and pyroxene yield values of 885 +- 53 Ma for the Apiai metagabro and 820 +- 84 Ma for the Adrianopolis metabasite. These results agree within error with the Rb/Sr isochron of 839 +- 85 Ma may possibly be interpreted as the time of extraction of the magma from the mantle, as suggested by positive epsilon{sub Nd(850)} values (+2,76) from an Adrianopolis sample. An epsilon{sub Nd} values versus 87 Sr/86 Sr diagram shows that each studied occurrence plots in a different position, following approximately the mantle array trend, the most primitive being the metabasite of Adrianopolis, near the MORB field, and the most enriched being the amphibolite from the same region, near the enriched mantle and or crustal contamination field. The distinct difference in isotopic signatures between the amphibolite and metabasite suggest derivation from different mantle sources, as supported by available geochemical data. Nevertheless, some of the samples show isotopic evidence of the action of metamorphism, crustal contamination and weathering. (author)

  19. Maintainability Improvement Through Corrosion Prediction

    Science.gov (United States)

    1997-12-01

    potential, current, pH, and chloride ion concentration were made along a simulated corrosion fatigue crack for HY80 (UNS K31820) steel in seawater...frequency range of 0.05-50 Hz, a 7075-T6 aluminium alloy and 304 and 316L stainless steels were fatigue tested in 3.0% NaCl solution. The increments...DESCRIPTORS: Conference Paper; Aluminum base alloys- Mechanical properties; Austenitic stainless steels - Mechanical properties; Corrosion fatigue

  20. METHOD OF ISOTOPE CONCENTRATION

    Science.gov (United States)

    Spevack, J.S.

    1957-04-01

    An isotope concentration process is described which consists of exchanging, at two or more different temperature stages, two isotopes of an element between substances that are physically separate from each other and each of which is capable of containing either of the isotopes, and withdrawing from a point between at least two of the temperatare stages one of the substances containing an increased concentration of the desired isotope.

  1. Statistical clumped isotope signatures

    NARCIS (Netherlands)

    Röckmann, T.; Popa, M. E.; Krol, M. C.; Hofmann, M. E. G.

    2016-01-01

    High precision measurements of molecules containing more than one heavy isotope may provide novel constraints on element cycles in nature. These so-called clumped isotope signatures are reported relative to the random (stochastic) distribution of heavy isotopes over all available isotopocules of a m

  2. Disturbance maintains alternative biome states.

    Science.gov (United States)

    Dantas, Vinícius de L; Hirota, Marina; Oliveira, Rafael S; Pausas, Juli G

    2016-01-01

    Understanding the mechanisms controlling the distribution of biomes remains a challenge. Although tropical biome distribution has traditionally been explained by climate and soil, contrasting vegetation types often occur as mosaics with sharp boundaries under very similar environmental conditions. While evidence suggests that these biomes are alternative states, empirical broad-scale support to this hypothesis is still lacking. Using community-level field data and a novel resource-niche overlap approach, we show that, for a wide range of environmental conditions, fire feedbacks maintain savannas and forests as alternative biome states in both the Neotropics and the Afrotropics. In addition, wooded grasslands and savannas occurred as alternative grassy states in the Afrotropics, depending on the relative importance of fire and herbivory feedbacks. These results are consistent with landscape scale evidence and suggest that disturbance is a general factor driving and maintaining alternative biome states and vegetation mosaics in the tropics.

  3. Chlorine isotope separation using an hydrous zirconium dioxide exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Heumann, K.G.; Baier, K.; Wibmer, G.

    1980-05-01

    Hydrous zirconium dioxide is used in column experiments for separating the halide ions as well as for isotope fractionation of chlorine. The preparation of the zirconium dioxide particles is carried out by homogeneous hydrolysis of a zirconyl chloride solution using hexamethylenetetramine. The separation order of the halides is I/sup -/, Br/sup -/ and Cl/sup -/ in contrast to the inverse separation order using a strongly basic anion exchange resin. In chlorine isotope separation experiments an enrichment of /sup 35/Cl/sup -/ is found in the first fractions, whereas the last fractions show a significant enrichment of /sup 37/Cl/sup -/. This also indicates an inversion of the isotope separation compared with a strongly basic anion exchange resin. A dependence of the isotope fractionation on the concentration of the NaNO/sub 3/ solution used as eluant is found. With increasing concentration the isotope fractionation decreases. Using a 0.5 M NaNO/sub 3/ solution the elementary separation effect was calculated epsilon = 6,1 x 10/sup -4/. This is one of the highest isotope fractionations known in a chloride isotope exchange system. The results show that the electrolyte behaviour of isotopes is comparable to that of a series of homologous elements.

  4. NMG documentation, part 3: maintainer`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, F.N.; Dickinson, R.P. Jr.

    1996-07-01

    This is the third of a three-part report documenting NMG, the Numerical Mathematics Guide. Part I is aimed at the user of the systenL It contains an introduction, with an out- line of the complete report, and Chapter 1, User`s Point of View. Part II is aimed at the programmer and contains Chapter 2, How It Works. Part III is aimed at the maintainer of NMG and contains Chapter 3, Maintenance, and Chapter 4, Validation. Because its contents are so specialized, Part III will receive only limited distribution. Note that each chapter has its own page numbering and table of contents.

  5. Generation of Radixenon Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    McIntyre, Justin I.; Bowyer, Ted W.; Hayes, James C.; Heimbigner, Tom R.; Morris, Scott J.; Panisko, Mark E.; Pitts, W. K.; Pratt, Sharon L.; Reeder, Paul L.; Thomas, Charles W.

    2003-06-30

    Pacific Northwest National Laboratory has developed an automated system for separating Xe from air and can detect the following radioxenon isotopes, 131mXe, 133mXe, 133Xe, and 135Xe. This report details the techniques used to generate the various radioxenon isotopes that are used for the calibration of the detector as well as other isotopes that have the potential to interfere with the fission produced radioxenon isotopes. Fission production is covered first using highly enriched uranium followed by a description and results from an experiment to produce radioxenon isotopes from neutron activation of ambient xenon.

  6. Isotopes in heterogeneous catalysis

    CERN Document Server

    Hargreaves, Justin SJ

    2006-01-01

    The purpose of this book is to review the current, state-of-the-art application of isotopic methods to the field of heterogeneous catalysis. Isotopic studies are arguably the ultimate technique in in situ methods for heterogeneous catalysis. In this review volume, chapters have been contributed by experts in the field and the coverage includes both the application of specific isotopes - Deuterium, Tritium, Carbon-14, Sulfur-35 and Oxygen-18 - as well as isotopic techniques - determination of surface mobility, steady state transient isotope kinetic analysis, and positron emission profiling.

  7. Control Inflation while Maintain Growth

    Institute of Scientific and Technical Information of China (English)

    Yang Junsheng

    2008-01-01

    @@ Dragged by the U.S.subprime crisis and the soaring oil price, the global economy is slowing down,causing problems to China, the country which has continuously achieved miraculous economic growth.Apart from the accumulation of high inflation and risks of overheated economy, China is attacked by serious natural disasters ever since the beginning of 2008,including the snow disaster, the earthquake and the flood.It is obviously that China's priority now is to bring inflation under control so as to maintain the stable growth of economy.

  8. Deuteration of piperylene on zeolite NaY

    Energy Technology Data Exchange (ETDEWEB)

    Kharlamov, V.V.; Kadentsev, V.I.; Kharatishvili, N.G.; Minachev, Kh.M.

    1982-04-20

    In order to further refine the mechanism of hydrogenation reaction on zeolites, the deuteration of piperylene on NaY was studied. The kinetic isotope effect in the hydrogenation of piperylene on zeolite NaY indicates that hydrogen takes part in the limiting step of the process and the 1-pentene and 2-pentene formed in the deuteration of piperylene have a wide isotope distribution, with a maximum amount of the d/sub 2/ isotope, and an average number of deuterium atoms in the molecules equal to 2.25-2.36.

  9. A versatile method for stable carbon isotope analysis of carbohydrates by high-performance liquid chromatography/isotope ratio mass spectrometry

    NARCIS (Netherlands)

    Boschker, H.T.S.; Moerdijk-Poortvliet, T.C.W.; Van Breugel, P.; Houtekamer, M.J.; Middelburg, J.J.

    2008-01-01

    We have developed a method to analyze stable carbon isotope (13C/12C) ratios in a variety of carbohydrates using high-performance liquid chromatography/isotope ratio mass spectrometry (HPLC/IRMS). The chromatography is based on strong anion-exchange columns with low strength NaOH eluents. An eluent

  10. Maintaining consistency in distributed systems

    Science.gov (United States)

    Birman, Kenneth P.

    1991-01-01

    In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.

  11. Software Code Maintainability : A Literature Review

    Directory of Open Access Journals (Sweden)

    Berna Seref

    2016-05-01

    Full Text Available Software Maintainability is one of the most important quality attributes. To increase quality of a software, to manage software more efficient and to decrease cost of the software, maintainability, maintainability estimation and maintainability evaluation models have been proposed. However, the practical use of these models in software engineering tools and practice remained little due to their limitations or threats to validity. In this paper, results of our Literature Review about maintainability models, maintainability metrics and maintainability estimation are presented. Aim of this paper is providing a baseline for further searches and serving the needs of developers and customers.

  12. Discovery of the Cobalt Isotopes

    OpenAIRE

    Szymanski, T.; Thoennessen, M.

    2009-01-01

    Twenty-six cobalt isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  13. Discovery of the Arsenic Isotopes

    CERN Document Server

    Shore, A; Heim, M; Schuh, A; Thoennessen, M

    2009-01-01

    Twenty-nine arsenic isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  14. Intracellular Cadmium Isotope Fractionation

    Science.gov (United States)

    Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

    2011-12-01

    Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

  15. Chromium isotope variations

    DEFF Research Database (Denmark)

    D'Arcy, Joan Mary

    is incorporated into carbonates. Hence, ancient carbonates can potentially record the Cr isotopic composition (δ53Cr ‰) of seawater in the geological past. Reliable application and interpretation of this proxy requires a detailed knowledge about processes that fractionate Cr on the Earth’s surface...... deposited during the Early Ordovician — a time of known redox instability in ancient oceans – exhibit a significant positive Cr isotope excursion of +0.5‰. This excursion is interpreted as the reductive drawn down of dissolved Cr in seawater in response to the development of a proximal anoxic sink......, and the quantification the Cr isotope composition of major Cr fluxes into and out of ocean. This thesis adds to the current knowledge of the Cr isotope system and is divided into two studies. The focus of the first study was to determine what processes control the Cr isotopic compositionof river water and to quantify...

  16. Isotopes in Greenland Precipitation

    DEFF Research Database (Denmark)

    Faber, Anne-Katrine

    Greenland ice cores offer a unique opportunity to investigate the climate system behaviour. The objective of this PhD project is to investigate isotope modelling of present- day conditions and conduct model-data comparison using Greenland ice cores. Thus this thesis investigates how the integration...... of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

  17. Maintaining quality in blood banking.

    Science.gov (United States)

    Harvey, E; Hewison, C; Nevalainen, D E; Lloyd, H L

    1995-03-01

    component will warrant redress. The degree of fault attributed to the producer will in part depend on whether they have met the best available standards at all stages in the preparation of the product. If a Transfusion Service can show that it's operation has external accreditation, particularly to an internationally recognised standard such as ISO 9000 and they can show that staff have been properly trained, that equipment is properly supplied and maintained and that the facility is appropriate to the work being carried out, then the liability that exists when something goes wrong will be reduced.(ABSTRACT TRUNCATED AT 400 WORDS)

  18. The Oxidant Budget of Dissolved Organic Carbon Driven Isotope Excursions

    Science.gov (United States)

    Bristow, T. F.; Kennedy, M. J.

    2008-12-01

    Negative carbon isotope values, falling below the mantle average of about -5 per mil, in carbonate phases of Ediacaran age sedimentary rocks are widely regarded as reflecting negative excursions in the carbon isotopic composition of seawater lasting millions of years. These isotopic signals form the basis of chemostratigraphic correlations between Ediacaran aged sections in different parts of the world, and have been used to track the oxidation of the biosphere. However, these isotopic values are difficult to accommodate within limits prescribed by the current understanding of the carbon cycle, and a hypothetical Precambrian ocean dissolved organic carbon (DOC) pool 100 to 1000 times the size of the modern provides a potential source of depleted carbon not considered in Phanerozoic carbon cycle budgets. We present box model results that show the remineralization of such a DOC pool to drive an isotope excursion of the magnitude observed in the geological record exhausts global budgets of free oxygen and sulfate in 800 k.y. These results are incompatible with the estimated duration of late Ediacaran isotope excursions of more than 10 m.y., as well as geochemical and biological indicators that oceanic sulfate and oxygen levels were maintained or even increased at the same time. Therefore the carbon isotope record is probably not a useful tool for monitoring oxygen levels in the atmosphere and ocean. Covariation between the carbon and oxygen isotope records is often observed during negative excursions and is indicative of local processes or diagenetic overprinting.

  19. Isotope Production and Distribution Program`s Fiscal Year 1997 financial statement audit

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-27

    The Department of Energy Isotope Production and Distribution Program mission is to serve the national need for a reliable supply of isotope products and services for medicine, industry and research. The program produces and sells hundreds of stable and radioactive isotopes that are widely utilized by domestic and international customers. Isotopes are produced only where there is no U.S. private sector capability or other production capacity is insufficient to meet U.S. needs. The Department encourages private sector investment in new isotope production ventures and will sell or lease its existing facilities and inventories for commercial purposes. The Isotope Program reports to the Director of the Office of Nuclear Energy, Science and Technology. The Isotope Program operates under a revolving fund established by the Fiscal Year (FY) 1990 Energy and Water Appropriations Act and maintains financial viability by earning revenues from the sale of isotopes and services and through annual appropriations. The FY 1995 Energy and Water Appropriations Act modified predecessor acts to allow prices charged for Isotope Program products and services to be based on production costs, market value, the needs of the research community, and other factors. Although the Isotope Program functions as a business, prices set for small-volume, high-cost isotopes that are needed for research purposes may not achieve full-cost recovery. As a result, isotopes produced by the Isotope Program for research and development are priced to provide a reasonable return to the U.S. Government without discouraging their use. Commercial isotopes are sold on a cost-recovery basis. Because of its pricing structure, when selecting isotopes for production, the Isotope Program must constantly balance current isotope demand, market conditions, and societal benefits with its determination to operate at the lowest possible cost to U.S. taxpayers. Thus, this report provides a financial analysis of this situation.

  20. Redução do nível de proteína bruta e suplementação de aminoácidos em rações para suínos machos castrados mantidos em ambiente termoneutro dos 30 aos 60 kg Reduction of crude protein levels of ration with amino acid supplementation to castrated swines maintained in a termoneutral environment from 30 to 60 kg

    Directory of Open Access Journals (Sweden)

    Rony Antonio Ferreira

    2005-04-01

    Full Text Available Este estudo foi conduzido para avaliar a influência da redução do nível de proteína bruta (PB da ração com suplementação de aminoácidos sobre o desempenho de suínos machos castrados (Landrace x Large White mantidos em ambiente termoneutro. Cinqüenta leitões mestiços (peso médio inicial de 30,2 kg foram distribuídos em delineamento experimental inteiramente ao acaso, com cinco tratamentos (17, 16, 15, 14 e 13% PB, cinco repetições e dois animais por unidade experimental. As rações experimentais e a água foram fornecidas à vontade até o final do experimento, quando os animais atingiram o peso médio de 60,2 kg. A temperatura média no interior da sala foi mantida em 22,0ºC e a umidade relativa média em 82,8%, correspondendo a um índice de temperatura de globo e umidade (ITGU de 69,2. A redução do nível de PB da ração influenciou o ganho de peso (GP dos animais; aqueles que consumiram a ração com 17% de PB apresentaram redução significativa no GP em relação aos que receberam as rações com 15 e 14% de PB. O consumo de ração e a conversão alimentar não foram influenciados pelos tratamentos. A redução do nível de PB aumentou as deposições de gordura e de proteína na carcaça e levou à diminuição da excreção de nitrogênio total. O nível de PB da ração para suínos machos dos 30 aos 60 kg mantidos em ambiente termoneutro pode ser reduzido de 17 para 13%, sem influenciar negativamente o desempenho, desde que as rações sejam devidamente suplementadas com aminoácidos essenciais limitantes.An study was conducted to evaluate the influence of reduction of crude protein (CP levels and amino acid supplementation in diets on the performance of castrated swines (Landracex Large White maintained in a termoneutral environment. Fifty crossbreed piglets (average initial body weight of 30.2 kg were allotted to a completely randomized experimental design with five treatments (17, 16, 15, 14 and 13% CP and

  1. Isotopic values of plants in relation to water availability in the Eastern Mediterranean region.

    Science.gov (United States)

    Hartman, Gideon; Danin, Avinoam

    2010-04-01

    Plant C and N isotope values often correlate with rainfall on global and regional scales. This study examines the relationship between plant isotopic values and rainfall in the Eastern Mediterranean region. The results indicate significant correlations between both C and N isotope values and rainfall in C(3) plant communities. This significant relationship is maintained when plant communities are divided by plant life forms. Furthermore, a seasonal increase in C isotope values is observed during the dry season while N isotope values remain stable across the wet and dry seasons. Finally, the isotopic pattern in plants originating from desert environments differs from those from Mediterranean environments because some desert plants obtain most of their water from secondary sources, namely water channeled by local topographic features rather than direct rainfall. From these results it can be concluded that water availability is the primary factor controlling C and N isotope variability in plant communities in the Eastern Mediterranean.

  2. Isotopes in Greenland Precipitation

    DEFF Research Database (Denmark)

    Faber, Anne-Katrine

    the Arctic Ocean. A comprehensive database is created based on ice core and weather station data from Greenland within the period 1890-2014. Present day annual and seasonal mean values are computed for 326 locations in Greenland. Parameterization of the spatial distribution of temperature and δ18O are used...... of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

  3. Perchlorate isotope forensics

    Science.gov (United States)

    Böhlke, J.K.; Sturchio, N.C.; Gu, B.; Horita, J.; Brown, G.M.; Jackson, W.A.; Batista, J.; Hatzinger, P.B.

    2005-01-01

    Perchlorate has been detected recently in a variety of soils, waters, plants, and food products at levels that may be detrimental to human health. These discoveries have generated considerable interest in perchlorate source identification. In this study, comprehensive stable isotope analyses ( 37Cl/35Cl and 18O/17O/ 16O) of perchlorate from known synthetic and natural sources reveal systematic differences in isotopic characteristics that are related to the formation mechanisms. In addition, isotopic analyses of perchlorate extracted from groundwater and surface water demonstrate the feasibility of identifying perchlorate sources in contaminated environments on the basis of this technique. Both natural and synthetic sources of perchlorate have been identified in water samples from some perchlorate occurrences in the United States by the isotopic method. ?? 2005 American Chemical Society.

  4. Isotope Production Facility (IPF)

    Data.gov (United States)

    Federal Laboratory Consortium — The Los Alamos National Laboratory has produced radioactive isotopes for medicine and research since the mid 1970s, when targets were first irradiated using the 800...

  5. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

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

  6. Isotopically controlled semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Haller, E.E.

    2004-11-15

    A review of recent research involving isotopically controlled semiconductors is presented. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, can be considered the most important one for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples. Manuel Cardona, the longtime editor-in-chief of Solid State Communications has been and continues to be one of the major contributors to this field of solid state physics and it is a great pleasure to dedicate this review to him.

  7. Isotopes through the looking glass

    Science.gov (United States)

    Mårtensson Pendrill, Ann Marie

    2000-08-01

    Nuclear distributions affect many aspects of atomic spectra. As an example, recent experimental results for the hyperfine anomaly in Fr isotopes are considered. These depend on nuclear charge and magnetization distributions. The variations in charge radii for these isotopes were studied earlier by measuring optical isotope shifts. The hyperfine anomalies for the odd-odd isotopes involve the neutron distributions, of interest for studies of parity nonconserving effects along a chain of isotopes.

  8. Methods of isotopic geochronology

    Science.gov (United States)

    Gorokhov, I. M.; Levchenkov, O. A.

    Papers are presented on such topics as the age of the chemical elements; the age of meteorites, the moon, and the earth; isotopic ages of the most ancient terrestrial formations; and the Archean evolution of Enderby Land in the Antarctic as evidenced by isotopic dating. Consideration is also given to a uranium-lead geochronology technique for investigating Precambrian ore deposits, a Pb-Pb technique of zircon dating, and the potentials and limitations of Sm-Nd geochronology.

  9. Oxygen Isotopes in Meteorites

    Science.gov (United States)

    Clayton, R. N.

    2003-12-01

    Oxygen isotope abundance variations in meteorites are very useful in elucidating chemical and physical processes that occurred during the formation of the solar system (Clayton, 1993). On Earth, the mean abundances of the three stable isotopes are 16O: 99.76%, 17O: 0.039%, and 18O: 0.202%. It is conventional to express variations in abundances of the isotopes in terms of isotopic ratios, relative to an arbitrary standard, called SMOW (for standard mean ocean water), as follows:The isotopic composition of any sample can then be represented by one point on a "three-isotope plot," a graph of δ17O versus δ18O. It will be seen that such plots are invaluable in interpreting meteoritic data. Figure 1 shows schematically the effect of various processes on an initial composition at the center of the diagram. Almost all terrestrial materials lie along a "fractionation" trend; most meteoritic materials lie near a line of "16O addition" (or subtraction). (4K)Figure 1. Schematic representation of various isotopic processes shown on an oxygen three-isotope plot. Almost all terrestrial materials plot along a line of "fractionation"; most primitive meteoritic materials plot near a line of "16O addition." The three isotopes of oxygen are produced by nucleosynthesis in stars, but by different nuclear processes in different stellar environments. The principal isotope, 16O, is a primary isotope (capable of being produced from hydrogen and helium alone), formed in massive stars (>10 solar masses), and ejected by supernova explosions. The two rare isotopes are secondary nuclei (produced in stars from nuclei formed in an earlier generation of stars), with 17O coming primarily from low- and intermediate-mass stars (shielding in the UV photodissociation of CO (van Dishoeck and Black, 1988). This process results from the large differences in abundance between C16O, on the one hand, and C17O and C18O on the other. Photolysis of CO occurs by absorption of stellar UV radiation in the

  10. Space maintainers in dentistry: past to present.

    Science.gov (United States)

    Setia, Vikas; Pandit, Inder Kumar; Srivastava, Nikhil; Gugnani, Neeraj; Sekhon, Harveen Kaur

    2013-10-01

    Early orthodontic interventions are often initiated in the developing dentition to promote favourable developmental changes. Interceptive orthodontic can eliminate or reduce the severity of a developing malocclusion, the complexity of orthodontic treatment, overall treatment time and cost. The safest way to prevent future malocclusions from tooth loss is to place a space maintainer that is effective and durable. An appropriate use of space maintainer is advocated to hold the space until the eruption of permanent teeth. This case report describes the various changing trends in use of space maintainers: conventional band and loop, prefabricated band with custom made loop and glass fibre reinforced composite resins as space maintainers.

  11. Chlorine isotope separation using an hydrous zirconium dioxide exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Heumann, K.G.; Baier, K.; Wibmer, G.

    1980-05-01

    Hydrous zirconium dioxide is used in column experiments for separating the halide ions as well as for isotope fractionation of chlorine. The preparation of the zirconium dioxide particles is carried out by homogeneous hydrolysis of a zirconyl chloride solution using hexamethylenetetramine. The separation order of the halides is I/sup -/, Br/sup -/ and Cl/sup -/ in contrast to the inverse separation order using a strongly basic anion exchange resin. In chlorine isotope separation experiments an enrichment of /sup 35/Cl/sup -/ is found in the first fractions, whereas the last fractions show a significant enrichment of /sup 37/Cl/sup -/. This also indicates an inversion of the isotope separation compared with a strongly basic anion exchange resin. A dependence of the isotope fractionation on the concentration of the NaNO/sub 3/ solution used as eluant is found. With increasing concentration the isotope fractionation decreases. Using a 0.5 M NaNO/sub 3/ solution the elementary separation effect was calculated epsilon done on different tantalum parts to determine the amount of dissolved hydrogen.

  12. Isotope geochemistry. Biological signatures in clumped isotopes of O₂.

    Science.gov (United States)

    Yeung, Laurence Y; Ash, Jeanine L; Young, Edward D

    2015-04-24

    The abundances of molecules containing more than one rare isotope have been applied broadly to determine formation temperatures of natural materials. These applications of "clumped" isotopes rely on the assumption that isotope-exchange equilibrium is reached, or at least approached, during the formation of those materials. In a closed-system terrarium experiment, we demonstrate that biological oxygen (O2) cycling drives the clumped-isotope composition of O2 away from isotopic equilibrium. Our model of the system suggests that unique biological signatures are present in clumped isotopes of O2—and not formation temperatures. Photosynthetic O2 is depleted in (18)O(18)O and (17)O(18)O relative to a stochastic distribution of isotopes, unlike at equilibrium, where heavy-isotope pairs are enriched. Similar signatures may be widespread in nature, offering new tracers of biological and geochemical cycling.

  13. Stable isotopes. Applications and production; Les isotopes stables. Applications - production

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, S.; Louvet, P.; Soulie, E. [eds.

    1994-12-31

    This conference presents 46 communications concerning stable isotope production, utilization and application, grouped in 6 sessions and posters. The various themes are: biological applications (pharmacology, medical diagnosis, metabolism and protein studies, toxicity and response studies, labelled compounds), analysis procedures (NMR analysis for macromolecules, tracer studies), nuclear applications (utilization of stable isotopes in nuclear reactors), biological, physical and chemical applications (mass transfer, mobility, crystallography, isotopic exchange), stable isotope production (ion chromatography, ion cyclotron resonance, cryogenic distillation).

  14. Deformation of C isotopes

    CERN Document Server

    Kanada-Enyo, Y

    2004-01-01

    Systematic analysis of the deformations of proton and neutron densities in even-even C isotopes was done based on the method of antisymmetrized molecular dynamics. The $E2$ transition strength was discussed in relation to the deformation. We analyze the $B(E2;2^+_1\\to 0^+_1)$ in $^{16}$C, which has been recently measured to be abnormally small. The results suggest the difference of the deformations between proton and neutron densities in the neutron-rich C isotopes. It was found that stable proton structure in C isotopes plays an important role in the enhancement the neutron skin structure as well as in the systematics of $B(E2)$ in the neutron-rich C.

  15. Isotopes in Condensed Matter

    CERN Document Server

    G Plekhanov, Vladimir

    2013-01-01

    This book provides a concise introduction to the newly created sub-discipline of solid state physics isotopetronics. The role of isotopes in materials and their properties are describe  in this book. The problem of the enigma of the atomic mass in microphysics is briefly discussed.  The range of the applications of isotopes is wide: from biochemical process in living organisms to modern technical applications in quantum information. Isotopetronics promises to improve nanoelectronic and optoelectronic devices. With numerous illustrations this book is useful to researchers, engineers and graduate students.

  16. Atomic Weights and Isotopic Compositions

    Science.gov (United States)

    SRD 144 Atomic Weights and Isotopic Compositions (Web, free access)   The atomic weights are available for elements 1 through 111, and isotopic compositions or abundances are given when appropriate.

  17. Isotope determination of sulfur by mass spectrometry in soil samples

    Directory of Open Access Journals (Sweden)

    Alexssandra Luiza Rodrigues Molina Rossete

    2012-12-01

    Full Text Available Sulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes (32S, 33S, 34S, and 36S with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO4(2-, which was determined by dry combustion with alkaline oxidizing agents. The total S-SO4(2- concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO2 gas, BaSO4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO3. The isotope determination of S (atom % 34S atoms was carried out by isotope ratio mass spectrometry (IRMS. In this work, the labeled material (K2(34SO4 was used to validate the method of isotopic determination of S; the results were precise and accurate, showing the viability of the proposed method.

  18. Magnesium isotope fractionation during differentiation of Harney Peak granite

    Science.gov (United States)

    Ke, S.; Teng, F.; Walker, R. J.

    2009-12-01

    Although numerous studies have sought to constrain the Mg isotopic composition of mantle rocks, few studies have focused on the Mg isotopic compositions of crustal rocks, particularly evolved igneous rocks, such as granites. Granites are a major component of the upper continental crust and can be produced by partial melting of the deep continental crust. Studies of granites, therefore, can potentially provide important constraints on Mg isotopic composition variations in the continental crust as related to sources and petrogenetic processes. In order to explore the behavior of Mg isotopes during partial melting of continental crust, as well as granite differentiation, we have begun a study of a set of well-characterized samples from S-type Harney Peak granite, its potential source rocks and associated Tin Mountain pegmatite from Black Hills, South Dakota, USA. δ26Mg values of Harney Peak granites and Tin Mountain pegmatite vary significantly (from -0.69 to +0.11), well beyond the range of their potential source rocks (from -0.40 to +0.15) — early Proterozoic schists and late Archean metagranites. The large Mg isotopic variations within the granite suite likely, in part, reflect heterogeneities in source rocks, as previously shown for oxygen and Nd isotopes. A greater cause of the variations may be fractionations that occur during partial melting and subsequent differentiation of granitic melts, as suggested by the correlations between δ26Mg with SiO2, Al2O3, Na2O and Sr.

  19. Discoveries of isotopes by fission

    Indian Academy of Sciences (India)

    M Thoennessen

    2015-09-01

    Of the about 3000 isotopes presently known, about 20% have been discovered in fission. The history of fission as it relates to the discovery of isotopes as well as the various reaction mechanisms leading to isotope discoveries involving fission are presented.

  20. GEOCHRONOMETRY ISOTOPE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>20040631 Chen Jiangfeng (School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui) ; Xie Zhi Relationships Between Rb-Sr, Ar - Ar Geochronometers and Oxygen Isotopic Equilibrium of Intrusions from Eastern Anhui Province, China (Geological Journal of China Universities, ISSN 1006 - 7493, CN 32 -

  1. GEOCHRONOMETRY & ISOTOPE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20090432 Zhou Shuqing (School of Energy Resources, China University of Geosciences Beijing 100083, China); Huang Haiping Stable Isotopic Records vs. Important Events in Life Evolution and the Concurrent Environment (Geological Review, ISSN0371-5736, CN11-1952, 54(2), 2008, p.225-231, 3 illus., 1 table, 77 refs.)

  2. GEOCHRONOMETRY & ISOTOPE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>20141014Wang Hairan(State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an710069,China);Zhao Hongge Theory and Application of Zircon U-Pb Isotope Dating Technique(Geology and Resources,ISSN1671-1947,CN21-1458/P,22(3),2013,p.229

  3. GEOCHRONOMETRY & ISOTOPE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>20072750 Huang Sijing(State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China);Pei Changrong Age Calibration for the Boundary between Lower and Middle Triassic by Strontium Isotope Stratigraphy in Eastern Sichuan Province

  4. GEOCHRONOMETRY & ISOTOPE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>20070454 Bao Zengkuan (Institute of High Energy Physics, CAS, Beijing 100049, China); Yuan Wanming Apatite (U-Th)/He Dating and Its Application (Acta Petrologica et Mineralogica, ISSN1000-6524, CN11-1966/P, 24(2), 2005, p.126-132, 2 illus., 25 refs.) Key words: isotopic geochronology

  5. Isotopic Implicit Surface Meshing

    NARCIS (Netherlands)

    Boissonnat, Jean-Daniel; Cohen-Steiner, David; Vegter, Gert

    2004-01-01

    This paper addresses the problem of piecewise linear approximation of implicit surfaces. We first give a criterion ensuring that the zero-set of a smooth function and the one of a piecewise linear approximation of it are isotopic. Then, we deduce from this criterion an implicit surface meshing algor

  6. Isotope hydrograph separation

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, P. [UFZ-Umweltforschungszentrum, Centre of Environmental Research Leipzig-Halle, Leipzig (Germany)

    2000-07-01

    Storm-runoff thus reflects the complex hydraulic behaviour of drainage basins and water-links of such systems. Water of different origin may participate in the events and in this lecture, the application of isotope techniques to separate storm hydrographs into different components will be presented.

  7. Forensic Stable Isotope Biogeochemistry

    Science.gov (United States)

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

    2016-06-01

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

  8. Sources and Information: Maintaining Institutional Integrity.

    Science.gov (United States)

    Palmer, Jim; Zwemer, Diane

    1985-01-01

    Provides an annotated bibliography of ERIC materials dealing with the community college mission, educational quality, maintaining an effective faculty, effects and management of retrenchment, and the state role in community college education. (LAL)

  9. Coastal Maintained Channels in US waters

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This layer shows coastal channels and waterways that are maintained and surveyed by the U.S. Army Corps of Engineers (USACE). These channels are necessary...

  10. Permanent traffic counters maintained by the NMDOT

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — A point dataset representing the permanent traffic counters maintained by the NMDOT. Event mapped dataset by LRS info provided by Traffic group.

  11. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Mølhave, Thomas; Revsbæk, Morten

    2015-01-01

    We study the problem of maintaining the contour tree T of a terrain Sigma, represented as a triangulated xy-monotone surface, as the heights of its vertices vary continuously with time. We characterize the combinatorial changes in T and how they relate to topological changes in Sigma. We present...... a kinetic data structure (KDS) for maintaining T efficiently. It maintains certificates that fail, i.e., an event occurs, only when the heights of two adjacent vertices become equal or two saddle vertices appear on the same contour. Assuming that the heights of two vertices of Sigma become equal only O(1......) times and these instances can be computed in O(1) time, the KDS processes O(kappa + n) events, where n is the number of vertices in Sigma and kappa is the number of events at which the combinatorial structure of T changes, and processes each event in O(log n) time. The KDS can be extended to maintain...

  12. Space Maintainers in Dentistry: Past to Present

    OpenAIRE

    Setia, Vikas; Pandit, Inder Kumar; Srivastava, Nikhil; Gugnani, Neeraj; Sekhon, Harveen Kaur

    2013-01-01

    Early orthodontic interventions are often initiated in the developing dentition to promote favourable developmental changes. Interceptive orthodontic can eliminate or reduce the severity of a developing malocclusion, the complexity of orthodontic treatment, overall treatment time and cost. The safest way to prevent future malocclusions from tooth loss is to place a space maintainer that is effective and durable. An appropriate use of space maintainer is advocated to hold the space until the e...

  13. Heavy element stable isotope ratios: analytical approaches and applications.

    Science.gov (United States)

    Tanimizu, Masaharu; Sohrin, Yoshiki; Hirata, Takafumi

    2013-03-01

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

  14. Collinear Resonance Ionization Spectroscopy of Neutron-Deficient Francium Isotopes

    CERN Document Server

    Flanagan, K T; Ruiz, R F Garcia; Budincevic, I; Procter, T J; Fedosseev, V N; Lynch, K M; Cocolios, T E; Marsh, B A; Neyens, G; Strashnov, I; Stroke, H H; Rossel, R E; Heylen, H; Billowes, J; Rothe, S; Bissell, M L; Wendt, K D A; de Groote, R P; De Schepper, S

    2013-01-01

    The magnetic moments and isotope shifts of the neutron-deficient francium isotopes Fr202-205 were measured at ISOLDE-CERN with use of collinear resonance ionization spectroscopy. A production-to-detection efficiency of 1\\% was measured for Fr-202. The background from nonresonant and collisional ionization was maintained below one ion in 10(5) beam particles. Through a comparison of the measured charge radii with predictions from the spherical droplet model, it is concluded that the ground-state wave function remains spherical down to Fr-205, with a departure observed in Fr-203 (N = 116).

  15. Trapping of radioactive {sup 21}Na

    Energy Technology Data Exchange (ETDEWEB)

    Kruithof, Wilbert L.; Hoek, Duurt J. van der; Giri, Gouri S.; Hoekstra, Ronnie; Hoekstra, Steven; Jungmann, Klaus; Onderwater, Gerco; Santra, Bodhaditya; Shildling, Praveen D.; Sohani, Moslem; Versolato, Oscar O.; Willmann, Lorenz; Wilschut, Hans W. [Kernfysisch Versneller Instituut, University Groningen (Netherlands)

    2010-07-01

    Radioactive {sup 21}Na atoms in a magneto-optical trap (MOT) provide an excellent opportunity to search for non-Standard Model contributions in the weak interactions. In particular, correlations between the {beta}-particle and the neutrino are sensitive to time reversal symmetry violating effects. The Na isotope is produced at the TRI{mu}P facility of the KVI using intense {sup 20}Ne beams from the AGOR cyclotron on a cooled deuterium target. The isotopes are stopped and re-thermalized in a Thermal Ionizer. They are transported as a low energy ion beam to a MOT cell where they are neutralized and subsequently captured by laser light. The trapped Na atoms will be transferred to a second MOT which is placed inside a reaction microscope to measure the momentum distribution of the recoiling daughter nuclei after the {beta}-decay. The {beta}-particle will be detected in a scintillation detector. These two devices have been characterized. A pulsed UV laser was used to ionize trapped Na atoms in order to simulate the {beta}-decay in the reaction microscope. The momentum distribution of the recoil ions is measured. The setup of the whole experiment will be presented.

  16. Water isotopes in desiccating lichens

    Science.gov (United States)

    Cuntz, Matthias; Máguas, Cristina; Lakatos, Michael

    2009-01-01

    The stable isotopic composition of water is routinely used as a tracer to study water exchange processes in vascular plants and ecosystems. To date, no study has focussed on isotope processes in non-vascular, poikilohydric organisms such as lichens and bryophytes. To understand basic isotope exchange processes of non-vascular plants, thallus water isotopic composition was studied in various green-algal lichens exposed to desiccation. The study indicates that lichens equilibrate with the isotopic composition of surrounding water vapour. A model was developed as a proof of concept that accounts for the specific water relations of these poikilohydric organisms. The approach incorporates first their variable thallus water potential and second a compartmentation of the thallus water into two isotopically distinct but connected water pools. Moreover, the results represent first steps towards the development of poikilohydric organisms as a recorder of ambient vapour isotopic composition. PMID:19888598

  17. Planos nutricionais com a utilização de aminoácidos e fitase para frangos de corte mantendo o conceito de proteína ideal nas dietas Nutritional plans with use of amino acids and phytase for broiler chickens maintaining the ideal protein profile in the diets

    Directory of Open Access Journals (Sweden)

    Elisangela Minati Gomide

    2007-12-01

    Full Text Available Objetivou-se neste estudo avaliar o desempenho e as características de carcaça de frangos de corte, recebendo rações com níveis reduzidos de PB, P disponível (Pd e Ca, suplementadas com fitase e aminoácidos. As fases de crescimento avaliadas foram: fase 1, 1 - 21dias de idade e fase 2, 22 - 42 dias de idade. O delineamento experimental foi inteiramente casualizado, sendo os tratamentos constituídos de cincos planos nutricionais (PN, com seis repetições de 25 aves cada. Os planos nutricionais são: PN1 - ração basal (21,4% PB - fase 1 + ração basal (19,3% PB - fase 2; PN2 - ração a basal (fase 1 + ração com 18% PB (fase 2; PN3 - ração basal (fase 1 + ração com 16% PB (fase 2; PN4 - ração com 19% PB (fase 1 + ração com 16% PB (fase 2; e PN5 = ração com 17 % PB (fase 1 + ração com 16% PB (fase 2. Exceto para a ração basal, reduziu-se o nível de Pd para 0,34 e 0,30% e o de Ca para 0,80 e 0,70% nas fases 1 e 2, respectivamente; nestas rações foram adicionados 500 FTU de fitase/kg de ração. As aves alimentadas com PN2 e PN3 apresentaram desempenho semelhante ao daquelas que receberam PN1, enquanto o das aves que receberam os PN4 e PN5 permaneceu inalterado. Os rendimentos de carcaça e peito não foram influenciados pelos planos nutricionais. As aves que consumiram a ração basal nas duas fases de criação (PN1 apresentaram maior rendimento de coxa+sobre-coxa. Houve aumento da gordura abdominal quando as aves receberam os PN3, 4 e 5. É possível reduzir a PB da ração até 16% na fase 2, suplementada com fitase e aminoácidos, desde que a ração da primeira fase seja formulada com níveis nutricionais recomendados.This study was carried out to evaluate the performance and characteristics of carcass of broiler chickens fed diets with reduced levels of CP, available P (aP and Ca, supplemented with phytase and amino acids. The growth phases evaluated were: Phase1, 1 - 21 days old, phase 2, 22 - 42 days old. A

  18. NA44 experiment

    CERN Document Server

    1990-01-01

    General view of NA44 experiment. NA44 is one of the seven experiments (NA44, NA45, NA49, NA50, NA52, WA97/NA57 and WA98) involved in CERN'S Heavy Ion programme which provided evidence for the existence of a new state of matter in which quarks, instead of being bound up into more complex particles such as protons and neutrons, are liberated and roam freely. Theory predicts that this state must have existed at about 10 microseconds after the Big Bang, before the formation of matter as we know it today.

  19. The gamma activities from the beta decay of /sup 27-34/Na and their descendants

    CERN Document Server

    Guillemaud, D; Détraz, C; Epherre-Rey-Campagnolle, Marcelle; Klapisch, Robert; Langevin, M; Naulin, F; Thibault, C; Touchard, F

    1981-01-01

    The gamma activities from the beta decay of Na isotopes up to /sup 34 /Na, which are formed in high energy fragmentation, are observed. The gamma intensities and delayed-neutron branching ratios P/sub n/ are measured. Preliminary decay schemes are obtained. (3 refs).

  20. s-Process Os isotope enrichment in ureilites by planetary processing

    Science.gov (United States)

    Goderis, S.; Brandon, A. D.; Mayer, B.; Humayun, M.

    2015-12-01

    Ubiquitous nucleosynthetic isotope anomalies relative to the terrestrial isotopic composition in Mo, Ru, and other elements are known from both bulk chondrites and differentiated meteorites, but Os isotope ratios reported from such meteorites have been found to be indistinguishable from the terrestrial value. The carriers of s- and r-process Os must thus have been homogeneously distributed in the solar nebula. As large Os isotope anomalies are known from acid leachates and residues of primitive chondrites, the constant relative proportions of presolar s- and r-process carriers in such chondrites must have been maintained during nebular processes. It has long been assumed that partial melting of primitive chondrites would homogenize the isotopic heterogeneity carried by presolar grains. Here, ureilites, carbon-rich ultramafic achondrites dominantly composed of olivine and low-Ca pyroxene, are shown to be the first differentiated bulk Solar System materials for which nucleosynthetic Os isotope anomalies have been identified. These anomalies consist of enrichment in s-process Os heterogeneously distributed in different ureilites. Given the observed homogeneity of Os isotopes in all types of primitive chondrites, this Os isotope variability among ureilites must have been caused by selective removal of s-process-poor Os host phases, probably metal, during rapid localized melting on the ureilite parent body. While Mo and Ru isotope anomalies for all meteorites measured so far exhibit s-process deficits relative to the Earth, the opposite holds for the Os isotope anomalies in ureilites reported here. This might indicate that the Earth preferentially accreted olivine-rich restites and inherited a s-process excess relative to smaller meteorite bodies, consistent with Earth's high Mg/Si ratio and enrichment of s-process nuclides in Mo, Ru, and Nd isotopes. Our new Os isotope results imply that caution must be used when applying nucleosynthetic isotope anomalies as provenance

  1. Cosmogenic radionuclide production in NaI(Tl) crystals

    Science.gov (United States)

    Amaré, J.; Cebrián, S.; Cuesta, C.; García, E.; Ginestra, C.; Martínez, M.; Oliván, M. A.; Ortigoza, Y.; Ortiz de Solórzano, A.; Pobes, C.; Puimedón, J.; Sarsa, M. L.; Villar, J. A.; Villar, P.

    2015-02-01

    The production of long-lived radioactive isotopes in materials due to the exposure to cosmic rays on Earth surface can be an hazard for experiments demanding ultra-low background conditions, typically performed deep underground. Production rates of cosmogenic isotopes in all the materials present in the experimental set-up, as well as the corresponding cosmic rays exposure history, must be both well known in order to assess the relevance of this effect in the achievable sensitivity of a given experiment. Although NaI(Tl) scintillators are being used in experiments aiming at the direct detection of dark matter since the first nineties of the last century, very few data about cosmogenic isotopes production rates have been published up to date. In this work we present data from two 12.5 kg NaI(Tl) detectors, developed in the frame of the ANAIS project, which were installed inside a convenient shielding at the Canfranc Underground Laboratory just after finishing surface exposure to cosmic rays. The very fast start of data taking allowed to identify and quantify isotopes with half-lives of the order of tens of days. Initial activities underground have been measured and then production rates at sea level have been estimated following the history of detectors; values of about a few tens of nuclei per kg and day for Te isotopes and 22Na and of a few hundreds for I isotopes have been found. These are the first direct estimates of production rates of cosmogenic nuclides in NaI crystals. A comparison of the so deduced rates with calculations using typical cosmic neutron flux at sea level and a carefully selected description of excitation functions will be also presented together with an estimate of the corresponding contribution to the background at low and high energies, which can be relevant for experiments aiming at rare events searches.

  2. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars; Mølhave, Thomas

    We consider maintaining the contour tree T of a piecewise-linear triangulation M that is the graph of a time varying height function h:R2→R. We carefully describe the combinatorial change in T that happen as h varies over time and how these changes relate to topological changes in M. We present...... a kinetic data structure that maintains the contour tree of h over time. Our data structure maintains certificates that fail only when h(v)=h(u) for two adjacent vertices v and u in M, or when two saddle vertices lie on the same contour of M. A certificate failure is handled in O(log(n)) time. We also show...

  3. Chromium isotope variations

    DEFF Research Database (Denmark)

    D'Arcy, Joan Mary

    is incorporated into carbonates. Hence, ancient carbonates can potentially record the Cr isotopic composition (δ53Cr ‰) of seawater in the geological past. Reliable application and interpretation of this proxy requires a detailed knowledge about processes that fractionate Cr on the Earth’s surface...... deposited during the Early Ordovician — a time of known redox instability in ancient oceans – exhibit a significant positive Cr isotope excursion of +0.5‰. This excursion is interpreted as the reductive drawn down of dissolved Cr in seawater in response to the development of a proximal anoxic sink...... of ancient marine sediments can be a useful tool for understanding the cycling of redox sensitive elements on a local scale....

  4. GEOCHRONOMETRY & ISOTOPE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    <正>20050934 Chen Zhihong (Chinese Academy of Geological Sciences, Beijing 100037, China); Lu Songnian Age of the Fushui Intermediate-Mafic Intrusive Complex in the Qinling Orogen, New Zircon U - Pb and Whole -Rock Sm and Nd Isotope Chronological Evidence (Geological Bulletin of China, ISSN 1671-2552, CN11-4648/P, 23(4), 2004, p. 322-328, 3 illus. , 3 tables, 10 refs. )

  5. GEOCHRONOMETRY &ISOTOPE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131727 Huang Xiaowen(State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550002,China);Qi Liang Preliminary Study on Sample-Preparation for Re-Os Isotopic Dating of Pyrite(Geochimica,ISSN0379-1726,CN44-1398/P,41(4),2012,p.380-386,3illus.,2tables,25refs)Key words:pyrite,Re-Os dating

  6. GEOCHRONOMETRY & ISOTOPE GEOLOGY

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20132601 Cui Yurong(Tianjin Institute of Geology and Mineral Resources,China Geological Survey,Tianjin 300170,China);Zhou Hongying In Situ LA-MC-ICP-MS U-Pb Isotopic Dating of Monazite(Acta Geoscientica Sinica,ISSN0375-5444,CN11-1856/P,33(6),2012,p.865-876,6illus.,4tables,41refs.)Key words:monazite,U-Pb dating

  7. ISOTOPE METHODS IN HOMOGENEOUS CATALYSIS.

    Energy Technology Data Exchange (ETDEWEB)

    BULLOCK,R.M.; BENDER,B.R.

    2000-12-01

    The use of isotope labels has had a fundamentally important role in the determination of mechanisms of homogeneously catalyzed reactions. Mechanistic data is valuable since it can assist in the design and rational improvement of homogeneous catalysts. There are several ways to use isotopes in mechanistic chemistry. Isotopes can be introduced into controlled experiments and followed where they go or don't go; in this way, Libby, Calvin, Taube and others used isotopes to elucidate mechanistic pathways for very different, yet important chemistries. Another important isotope method is the study of kinetic isotope effects (KIEs) and equilibrium isotope effect (EIEs). Here the mere observation of where a label winds up is no longer enough - what matters is how much slower (or faster) a labeled molecule reacts than the unlabeled material. The most careti studies essentially involve the measurement of isotope fractionation between a reference ground state and the transition state. Thus kinetic isotope effects provide unique data unavailable from other methods, since information about the transition state of a reaction is obtained. Because getting an experimental glimpse of transition states is really tantamount to understanding catalysis, kinetic isotope effects are very powerful.

  8. Maintaining collections with a flat budget

    Directory of Open Access Journals (Sweden)

    Sara E Morris

    2017-03-01

    Full Text Available This paper focuses on the various processes, methods and tough decisions made by the University of Kansas Libraries to provide library materials while maintaining a flat collections budget for over eight years. During this period, those responsible for the Libraries’ collections have implemented quick stop- gap measures, picked all the ‘low-hanging fruit’, and eventually canceled a large journal package. This case study will help other librarians facing the reality of maintaining collections at a time when budgets, changing formats and publication practices are all obstacles to providing patrons with what they need.

  9. Automated Methods to Maintain Aircraft Separation

    Science.gov (United States)

    Lauderdale, Todd

    2011-01-01

    The air traffic control system in the United States has a great track-record for safety. As more aircraft enter the system at a given time, the situation becomes more complex though. Researchers at NASA are attempting to leverage advances in many fields including optimization, data mining, and numerical modeling of systems to improve the air-transportation system maintaining safety while increasing throughput and reducing delays. This talk will give a brief overview of the research at NASA towards modernizing the air-transportation system. It will then focus on the specific area of automation tools for maintaining physical separation between aircraft known as Separation Assurance.

  10. Nuclear physics and stable isotopes; Physique nucleaire et isotopes stables

    Energy Technology Data Exchange (ETDEWEB)

    Goutte, D. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee

    1994-12-31

    The aim of this paper is to show that fundamental research in nuclear physics requires utilization of stable isotopes; stable isotopes are essential as target material since a large quantity of nucleus have to be studied in order to appreciate all the complexity of the nuclear structure, but also as a tool, such as beams, for the same purpose. Examples are given with samarium, tin and germanium isotopes. 7 figs.

  11. Kinetic control on Zn isotope signatures recorded in marine diatoms

    Science.gov (United States)

    Köbberich, Michael; Vance, Derek

    2017-08-01

    Marine diatoms dominate the oceanic cycle of the essential micronutrient zinc (Zn). The stable isotopes of zinc and other metals are increasingly used to understand trace metal micronutrient cycling in the oceans. One clear feature of the early isotope data is the heavy Zn isotope signature of the average oceanic dissolved pool relative to the inputs, potentially driven by uptake of light isotopes into phytoplankton cells and export to sediments. However, despite the fact that diatoms strip Zn from surface waters across the Antarctic polar front in the Southern Ocean, the local upper ocean is not isotopically heavy. Here we use culturing experiments to quantify the extent of Zn isotope fractionation by diatoms and to elucidate the mechanisms driving it. We have cultured two different open-ocean diatom species (T. oceanica and Chaetoceros sp.) in a series of experiments at constant medium Zn concentration but at bioavailable medium Fe ranging from limiting to replete. We find that T. oceanica can maintain high growth rates and Zn uptake rates over the full range of bioavailable iron (Fe) investigated, and that the Zn taken up has a δ66Zn that is unfractionated relative to that of the bioavailable free Zn in the medium. The studied representative of the genus Chaetoceros, on the other hand, shows more significantly reduced Zn uptake rates at low Fe and records more variable biomass δ66Zn signatures, of up to 0.85‰ heavier than the medium. We interpret the preferential uptake of heavy isotopes at extremely low Zn uptake rates as potentially due to either of the following two mechanisms. First, the release of extracellular polymeric substances (EPS), at low Fe levels, may preferentially scavenge heavy Zn isotopes. Second, the Zn uptake rate may be slow enough to establish pseudo-equilibrium conditions at the transporter site, with heavy Zn isotopes forming more stable surface complexes. Thus we find that, in our experiments, Fe-limitation exerts a key control that

  12. $\\beta$-NMR measurement of the nuclear quadrupole moments of $^{20,26-31}$Na

    CERN Document Server

    Wilbert, S; Geithner, W; Georg, U; Kappertz, S; Keim, M; Lievens, P; Neugart, R; Neuroth, M; Vermeeren, L

    1998-01-01

    The quadrupole moments of the neutron-rich isotopes $^{26-31}$Na and of the neutron-deficient $^{20}$Na were measured by $\\beta$-NMR after implantation of the short-lived nuclei into the host crystal lattices of Mg, LiNbO$_{3}$ and NaNO$_{3}$. The ion beams from ISOLDE were neutralized and polarized by in-beam optical pumping. Of particular interest are the isotopes close to N=20 for which various experimental observations suggest rather strong deformation. (5 refs) .

  13. Cd Isotope Fractionation During Adsorption Varies with Salinity

    Science.gov (United States)

    Wasylenki, L. E.; Montanez, G.; Anbar, A. D.

    2009-12-01

    Because its marine concentration profile is very similar to that of phosphate [1], Cd is considered to have potential as a paleophosphate or paleonutrient proxy in the geologic record. Previous work [2,3] has established that lighter isotopes of Cd are preferentially assimilated by phytoplankton, leaving surface waters isotopically heavy. Another recent study [4] suggests that analysis of Cd isotope variations in transects of ferromanganese crusts could reveal past variations in the extent to which Cd, and thus phosphate, has been depleted over time. This idea presumes that the extent of consumption of Cd by phytoplankton is reflected in the isotopic composition of seawater and that the Cd isotopic composition of seawater is in turn faithfully recorded in ferromanganese crusts. To test the latter assumption, Rehkämper et al. [4] measured the Cd isotopic composition of 15 Fe-Mn crusts from various ocean basins and found that 13 of those samples were within analytical error of the Cd isotopic composition of deep seawater from [3], indicating that Cd often does not fractionate appreciably during incorporation into ferromanganese crusts. Other studies [5,6] have likewise revealed little or no variation in Cd isotopic compositions among various terrestrial rocks and carbonaceous chondrites, suggesting that few earth processes significantly fractionate Cd isotopes. To test this conclusion experimentally, we performed adsorption experiments in which aqueous Cd was allowed to adsorb to synthetic birnessite (Mn oxyhydroxide). Stock solutions of dissolved Cd and birnessite suspension were mixed and agitated from 1 to 48 hours at room temperature. Some experiments had 0.1m KNO3 as background electrolyte, while others had 0.3m NaCl + 0.1m KNO3. After filtration, both the fluid with remaining dissolved Cd and solids with adsorbed Cd were purified with anion exchange chemistry. Column yields and proportions of dissolved and adsorbed Cd were determined by ICP-MS, and isotope

  14. Nickel isotopes and methanogens

    Science.gov (United States)

    Neubeck, A.; Ivarsson, M.

    2013-12-01

    Methanogens require Ni for their growth and as a consequence the microbial fractionation of Ni isotopes can be used as a biomarker for activity of methanogenic communities1. Anaerobic laboratory experiments was performed using methanogens to investigate methanogenic growth in a modified nutrient media2 with olivine Fo91 (5g/l) added as an additional mineral nutrient source and as the only H2 provider. One of the investigated methanogens showed an increased growth in the experiments with added olivine. There were also a close relationship between the mobilized Ni and the growth of the methanogen. Ni is an element that previously has been neglected in the study of fossilized microorganisms and their interaction with mineral substrates and, thus, there are no records or published data of Ni in association with microfossils. However, we have detected enrichments of Ni in fossilized microorganisms and ichno-fossils, respectively, from three separate locations. Ni is not present in the host rock in any of the samples. Thus, Ni is present in association with fossilized microorganisms from environments and more extensive analysis is required to understand the magnitude, uptake, preservation and fractionation of Ni in microfossils. In order to analyze Ni isotope fractionation from microbe-mineral interaction, we plan to use a high-resolution Laser-Ablation Time-of-Flight Mass Spectrometer (LMS)3. In situ profile ablation will provide detailed and localized data on fractionation patterns between microfossils and their host rock. Also, this technique will allow us to identify the change in Ni isotopic fractionation in rock samples caused by abiotic and biogenic processes in a faster and easier way and with less risk for contamination compared to the wet chemistry analyses of Ni isotopes. 1. Cameron, V., Vance, D., Archer, C. & House, C. H. A biomarker based on the stable isotopes of nickel. Proceedings of the National Academy of Sciences 106, 10944-10948 (2009). 2. Schn

  15. Maintaining an Operational Flight Program (OFP)

    Science.gov (United States)

    1991-10-01

    Monitor And Control ( PMAC ), as an example, allows a maintainer to interact with his running OFP. Other specialized environment testing might indicate...paths on the F-15’s Central Computer. Processor Peculiar Tests Specialized testing for unique features of ECSs. Programmable Monitor And Control ( PMAC

  16. How to Maintain a Social Reinforcement Program.

    Science.gov (United States)

    Arkin, Ronald; And Others

    This manual presents methodology for maintaining a social reinforcement system after supervisors in industrial environments have been trained in behavior modification theory and application. The maintenance manual discusses monitoring, evaluation, and integration of a company's employee performance system with the social reinforcement system…

  17. The randomized complexity of maintaining the minimum

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Chaudhuri, Shiva; Radhakrishnan, Jaikumar

    1996-01-01

    The complexity of maintaining a set under the operations Insert, Delete and FindMin is considered. In the comparison model it is shown that any randomized algorithm with expected amortized cost t comparisons per Insert and Delete has expected cost at least n/(e22t)-1 comparisons for FindMin. If F...

  18. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars; Mølhave, Thomas

    We consider maintaining the contour tree T of a piecewise-linear triangulation M that is the graph of a time varying height function h:R2→R. We carefully describe the combinatorial change in T that happen as h varies over time and how these changes relate to topological changes in M. We present...

  19. Maintaining Hope in the Face of Evil.

    Science.gov (United States)

    Miller, Geri

    2002-01-01

    P. G. Zimbardo (2001) and M. E. P. Seligman (in an interview with S. Carpenter, 2001) discuss evil and hope in response to the September 11, 2001, disaster. The implications for counseling are presented with an emphasis on how counselors can maintain hope for themselves and their clients in the face of evil. (Author)

  20. Maintaining ideal body weight counseling sessions

    Energy Technology Data Exchange (ETDEWEB)

    Brammer, S.H.

    1980-10-09

    The purpose of this program is to provide employees with the motivation, knowledge and skills necessary to maintain ideal body weight throughout life. The target audience for this program, which is conducted in an industrial setting, is the employee 40 years of age or younger who is at or near his/her ideal body weight.

  1. Treating Problem Behaviors Maintained by Negative Reinforcement.

    Science.gov (United States)

    Cipani, Ennio; Spooner, Fred

    1997-01-01

    Identifies four treatment techniques that may be applied when problem behavior is maintained by negative reinforcement: (1) functional communication training; (2) behavioral momentum; (3) differential reinforcement or an alternative escape behavior; and (4) errorless learning. Each of the techniques is defined, and applications and guidelines for…

  2. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Mølhave, Thomas; Revsbæk, Morten;

    2015-01-01

    We study the problem of maintaining the contour tree T of a terrain Sigma, represented as a triangulated xy-monotone surface, as the heights of its vertices vary continuously with time. We characterize the combinatorial changes in T and how they relate to topological changes in Sigma. We present ...

  3. How Do Positive Views Maintain Life Satisfaction?

    Science.gov (United States)

    Wu, Chia-Huei; Tsai, Ying-Mei; Chen, Lung Hung

    2009-01-01

    This study proposes three mediation pathways to explain how the positive views (perceived control, optimism and self-enhancement) proposed by Cummins and Nistico (Journal of Happiness Studies 3:37-69 2002) maintain life satisfaction. The three pathways were enhancing self-esteem, reducing have-want discrepancy and changing importance perceptions.…

  4. Maintaining strategic momentum : The CEO's agenda

    NARCIS (Netherlands)

    F.M. Maljers (Floris); C.W.F. Baden-Fuller (Charles); F.A.J. van den Bosch (Frans)

    1996-01-01

    textabstractThe question of how the CEO of a large complex organization maintain strategic momentum is addressed. This represents a great challenge when there are no obvious external threats, and no obvious reasons for having a concerted action. The inherent tensions which exist between stability an

  5. Therapeutic use of radioactive isotopes

    CERN Multimedia

    Caroline Duc

    2013-01-01

    In December, researchers from ISOLDE-CERN, the Paul Scherrer Institute (PSI) and the Institut Laue-Langevin (ILL) published the results of an in vivo study which successfully proved the effectiveness of four terbium isotopes for diagnosing and treating cancerous tumours.   Four terbium isotopes suitable for clinical purposes. “ISOLDE is the only installation capable of supplying terbium isotopes of such purity and intensity in the case of three out of the four types used in this study,” explains Karl Johnson, a physicist at ISOLDE.  “Producing over a thousand different isotopes, our equipment offers the widest choice of isotopes in the world!” Initially intended for fundamental physics research, ISOLDE has diversified its activities over time to invest in various projects in the materials science, biochemistry and nuclear medicine fields. The proof-of-concept study has confirmed that the four terbium isotopes 149Tb, 152Tb, 155Tb produ...

  6. Lithium isotope separation by laser

    Energy Technology Data Exchange (ETDEWEB)

    Arisawa, T.; Maruyama, Y.; Suzuki, Y.; Shiba, K.

    1982-01-01

    A lithium isotope separation was performed using a laser isotope separation method. It was found that the lithium atoms with a natural isotopic abundance enhanced its /sup 6/Li concentration up to over 90% by tuning the laser wavelength to the /sup 2/Psub(1/2) of /sup 6/Li. Too high power, however, leads to a loss of enrichment due to the power broadening effect which was analysed by the equation of motion of density matrices.

  7. Operational handbook of the Bretby Maintainability Index

    Energy Technology Data Exchange (ETDEWEB)

    Rushworth, A.M.; Mason, S.; Talbot, C. (British Coal Corporation, Stanhope Bretby (United Kingdom). Technical Services and Research Executive, Ergonomics Branch)

    1994-01-01

    A substantial proportion of the injuries and costs in the mining industry, and in industry generally, occur during maintenance activities, particularly in work involving plant and machinery. A common thread linking the cause of these accidents and losses is a general deficiency in machine design, particularly the ergonomic aspects. This report concerns the Bretby Maintainability Index (BMI) which provides a comprehensive method of analysing and quantifying machinery maintainability in terms of health and safety and the financial implications associated with excessive downtime. The health and safety implications of poor machine design are discussed, as are the cost implications. The concept of the BMI is outlined and information on its application is given. Its detailed features are presented and guidance notes are provided.

  8. Maintainability Prediction and Analysis Study. Revision A

    Science.gov (United States)

    1978-07-01

    SS- 6b SECTION 1.0 INTRiODUCTION This document presents the results of a study to develop and document an improved maintainability prediction and...include operations on other RIs called out in the jth fault iscolation result . Tmujn Average time to perform the ruth corrective maintenance step for...of the study however, as the resulting time standards are used as Inputs In computing disassembly, interchange, and reassembly times for the

  9. Maintaining Multimedia Data in a Geospatial Database

    Science.gov (United States)

    2012-09-01

    ID (SRID). “The SRID is the spatial reference identification system. The SRID is part of a set of standards developed for cartography , surveying...in a GIS are stored in two-dimensional space, which adds to the complexities faced in simulating a databases’ workload when the data is three...benchmark testing. A. OVERVIEW In creating a GIS that maintains multimedia data, it is first important to note that the actual multimedia data is

  10. Maintaining Wolbachia in Cell-free Medium

    OpenAIRE

    Gamston, Courtney; Rasgon, Jason

    2007-01-01

    In this video protocol, procedures are demonstrated to (1) purify Wolbachia symbionts out of cultured mosquito cells, (2) use a fluorescent assay to ascertain the viability of the purified Wolbachia and (3) maintain the now extracellular Wolbachia in cell-free medium. Purified Wolbachia remain alive in the extracellular phase but do not replicate until re-inoculated into eukaryotic cells. Extracellular Wolbachia purified in this manner will remain viable for at least a week at ...

  11. Cold regions isotope applications

    Energy Technology Data Exchange (ETDEWEB)

    Perrigo, L.D.; Divine, T.E.

    1976-04-01

    Pacific Northwest Laboratories (PNL) started the Cold Regions Isotope Applications Program in FY-1975 to identify special conditions in the Arctic and similar geographic areas (Cold Regions) where radioisotope power, heater, or sterilization systems would be desirable and economically viable. Significant progress was made in the first year of this program and all objectives for this initial 12-month period were achieved. The major conclusions and recommendations resulting for this effort are described below. The areas of interest covered include: radiosterilization of sewage; heating of septic tanks; and radioisotope thermoelectric generators as power sources for meteorological instruments and navigational aids. (TFD)

  12. Carbon-isotopic analysis of dissolved acetate.

    Science.gov (United States)

    Gelwicks, J T; Hayes, J M

    1990-01-01

    Heating of dried, acetate-containing solids together with oxalic acid dihydrate conveniently releases acetic acid for purification by gas chromatography. For determination of the carbon-isotopic composition of total acetate, the acetate-containing zone of the chromatographic effluent can be routed directly to a combustion furnace coupled to a vacuum system allowing recovery, purification, and packaging of CO2 for mass-spectrometric analysis. For analysis of methyl carbon, acetic acid can be cryogenically trapped from the chromatographic effluent, then transferred to a tube containing excess NaOH. The tube is evacuated, sealed, and heated to 500 degrees C to produce methane by pyrolysis of sodium acetate. Subsequent combustion of the methane allows determination of the 13C content at the methyl position in the parent acetate. With typical blanks, the standard deviation of single analyses is less than 0.4% for acetate samples larger than 5 micromoles. A full treatment of uncertainties is outlined.

  13. Angelite: Paziteli na vhoda

    Directory of Open Access Journals (Sweden)

    Gerov Georgi

    2009-01-01

    Full Text Available (bugarski Statijata prosledjava ikonografskata evoljucija na izobraženijata na arhangelite Mihail i Gavriil, pomesteni pri vhoda na pravoslavnija hram. Povraten moment v neja e 13 vek. Togava arhangel Mihail započva da se izobrazjava kato voin. S tova apotropejnite mu funkcii namirat adekvaten vizualen izraz. K'm kraja na stoletieto arhangel Gavriil započva da se izobrazjava kato pisar - ikonografija, kojato šče b'de dorazvita i utv'rdena prez 14 vek. Prez postvizantijskata epoha v obraza na Mihail se pojavjavat elementi, koito akcentirat v'rhu roljata mu na psihopomp.

  14. Si Isotopes of Brownleeite

    Science.gov (United States)

    Nakamura-Messenger, K.; Messenger, Scott R.; Ito, M.; Keller, L. P.; Clemett, S. J.; Jones, J. H.; Tatsuoka, H.; Zolensky, M. E.; Tatsuoka, H.

    2010-01-01

    Brownleeite is a manganese silicide, ideally stoichiometric MnSi, not previously observed in nature until its discovery within an interplanetary dust particle (IDP) that likely originated from a comet [1]. Three discrete brownleeite grains in the IDP L2055 I3 (4 microns in size, hereafter IDP I3) were identified with maximum dimensions of 100, 250 and 600 nm and fully analyzed using scanning-transmission electron microscopy (STEM) [1]. One of the grains (100 nm in size) was poikilitically enclosed by low-Fe, Mn-enriched (LIME) olivine. LIME olivine is epitaxial to the brownleeite with the brownleeite (200) parallel to the olivine c* [1]. LIME olivine is an enigmatic phase first reported from chondritic porous IDPs and some unequilibrated ordinary chondrites [ 2], that is commonly observed in chondritic-porous IDPs. Recently, LIME olivine has been also found in comet Wild-2 (Stardust) samples [3], indicating that LIME olivine is a common mineral component of comets. LIME olivine has been proposed to form as a high temperature condensate in the protosolar nebula [2]. Brownleeite grains also likely formed as high-temperature condensates either in the early Solar System or in the outflow of an evolved star or supernova explosion [1]. The isotopic composition of the brownleeite grains may strongly constrain their ultimate source. To test this hypothesis, we performed isotopic analyses of the brownleeite and the associated LIME olivine, using the NASA/JSC NanoSIMS 50L ion microprobe.

  15. Calcium isotopes in wine

    Science.gov (United States)

    Holmden, C. E.

    2011-12-01

    The δ 44/40Ca values of bottled wine vary between -0.76% to -1.55% on the seawater scale and correlate weakly with inverse Ca concentration and Mg/Ca ratio, such that the lowest δ 44/40Ca values have the highest Ca concentrations and lowest Mg/Ca ratios. The correlation is notable in the sense that the measured wines include both whites and reds sampled from different wine growing regions of the world, and cover a wide range of quality. Trends among the data yield clues regarding the cause of the observed isotopic fractionation. White wines, and wines generally perceived to be of lower quality, have lower δ 44/40Ca values compared to red wines and wines of generally perceived higher quality. Quality was assessed qualitatively through sensory evaluation, price, and scores assigned by critics. The relationship between δ 44/40Ca and wine quality was most apparent when comparing wines of one varietal from one producer from the same growing region. In the vineyard, wine quality is related to factors such as the tonnage of the crop and the ripeness of the grapes at the time of harvesting, the thickness of the skins for reds, the age of the vines, as well as the place where the grapes were grown (terroir). Quality is also influenced by winemaking practices such as fermentation temperature, duration of skin contact, and barrel ageing. Accordingly, the relationship between δ 44/40Ca and wine quality may originate during grape ripening in the vineyard or during winemaking in the cellar. We tested the grape ripening hypothesis using Merlot grapes sampled from a vineyard in the Okanagan, British Columbia, using sugar content (degrees Brix) as an indicator of ripeness. The grapes were separated into pulp, skin, and pip fractions and were analyzed separately. Thus far, there is no clear evidence for a systematic change in δ 44/40Ca values associated with progressive ripening of grapes in the vineyard. On the day of harvesting, the δ 44/40Ca value of juice squeezed from

  16. Store operations to maintain cache coherence

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

    2017-09-12

    In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

  17. Store operations to maintain cache coherence

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

    2017-08-01

    In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

  18. Storage methods to maintain a tulip collection

    OpenAIRE

    Bonnier, F.J.M.; Eikelboom, W.; Tuyl, van, J.M.

    1997-01-01

    Collections of tulip genotypes are maintained by yearly planting, harvesting and storage of the bulbs. To optimise the maintenance, two methods were examined for their suitability to store bulbs for one or more growing seasons. Method 1: bulbs were stored after flower development at -2 °C. Method 2: bulbs were stored before the start of flower development at -0.5 °C, followed by a temperature regime of 4 weeks 25 °C, 6 weeks 20 °C and 16 weeks 5 °C, for development of sprouts. With the first ...

  19. Take Control of Maintaining Your Mac

    CERN Document Server

    Kissell, Joe

    2009-01-01

    Keep your Mac running smoothly with our easy maintenance program! Regular maintenance is necessary to avoid problems and to ensure your Mac runs at peak performance, but it's hard to know what to do and when to do it. Best-selling author Joe Kissell has now applied his commonsense approach to the task of maintaining your Mac, whether you use Tiger or Leopard! Learn how to start on the right foot; what you should do daily, weekly, monthly, and yearly; and how to prepare for Mac OS X updates. Joe even explains how to monitor your Mac's health and debunks common panaceas. Read this book to lea

  20. Spontaneous NA+ transients in individual mitochondria of intact astrocytes.

    Science.gov (United States)

    Azarias, Guillaume; Van de Ville, Dimitri; Unser, Michael; Chatton, Jean-Yves

    2008-02-01

    Mitochondria in intact cells maintain low Na(+) levels despite the large electrochemical gradient favoring cation influx into the matrix. In addition, they display individual spontaneous transient depolarizations. The authors report here that individual mitochondria in living astrocytes exhibit spontaneous increases in their Na(+) concentration (Na(mit)(+) spiking), as measured using the mitochondrial probe CoroNa Red. In a field of view with approximately 30 astrocytes, up to 1,400 transients per minute were typically detected under resting conditions. Na(mit)(+) spiking was also observed in neurons, but was scarce in two nonneural cell types tested. Astrocytic Na(mit)(+) spikes averaged 12.2 +/- 0.8 s in duration and 35.5 +/- 3.2 mM in amplitude and coincided with brief mitochondrial depolarizations; they were impaired by mitochondrial depolarization and ruthenium red pointing to the involvement of a cation uniporter. Na(mit)(+) spiking activity was significantly inhibited by mitochondrial Na(+)/H(+) exchanger inhibition and sensitive to cellular pH and Na(+) concentration. Ca(2+) played a permissive role on Na(mit)(+) spiking activity. Finally, the authors present evidence suggesting that Na(mit)(+) spiking frequency was correlated with cellular ATP levels. This study shows that, under physiological conditions, individual mitochondria in living astrocytes exhibit fast Na(+) exchange across their inner membrane, which reveals a new form of highly dynamic and localized functional regulation.

  1. Maintaining heterokaryosis in pseudo-homothallic fungi.

    Science.gov (United States)

    Grognet, Pierre; Silar, Philippe

    2015-01-01

    Among all the strategies displayed by fungi to reproduce and propagate, some species have adopted a peculiar behavior called pseudo-homothallism. Pseudo-homothallic fungi are true heterothallics, i.e., they need 2 genetically-compatible partners to mate, but they produce self-fertile mycelium in which the 2 different nuclei carrying the compatible mating types are present. This lifestyle not only enables the fungus to reproduce without finding a compatible partner, but also to cross with any mate it may encounter. However, to be fully functional, pseudo-homothallism requires maintaining heterokaryosis at every stage of the life cycle. We recently showed that neither the structure of the mating-type locus nor hybrid-enhancing effect due to the presence of the 2 mating types accounts for the maintenance of heterokaryosis in the pseudo-homothallic fungus P. anserina. In this addendum, we summarize the mechanisms creating heterokaryosis in P. anserina and 2 other well-known pseudo-homothallic fungi, Neurospora tetrasperma and Agaricus bisporus. We also discuss mechanisms potentially involved in maintaining heterokaryosis in these 3 species.

  2. Maintaining extensivity in evolutionary multiplex networks

    CERN Document Server

    Antonopoulos, Chris G

    2015-01-01

    In this Letter, we explore the role of network topology on its extensive character. We study analytically and numerically how the topology contributes to maintaining extensivity of entropy in multiplex networks, i.e. networks of subnetworks, by means of the sum of the positive Lyapunov exponents, $H_{KS}$, a quantity related to entropy. We show that extensivity relies not only on the interplay between the coupling strengths of the dynamics associated to the intra (short-range) and inter (long-range) interactions, but also on the sum of the intra-degrees of the nodes of the subnetworks. For the analytically treated networks of size $N$, if the sum of the intra-degrees (and the sum of inter-degrees) scales as $N^{\\theta+1}$, extensivity can be maintained if the intra-coupling (and the inter-coupling) strength scales as $N^{-\\theta}$, when evolution is driven by the maximization of $H_{KS}$. We then verify our analytical result by doing numerical simulations in multiplex networks formed by electrically and chemi...

  3. Experience of maintaining laboratory educational website's sustainability

    Science.gov (United States)

    Dimenstein, Izak B.

    2016-01-01

    Laboratory methodology websites are specialized niche websites. The visibility of a niche website transforms it into an authority site on a particular “niche of knowledge.” This article presents some ways in which a laboratory methodology website can maintain its sustainability. The optimal composition of the website includes a basic content, a blog, and an ancillary part. This article discusses experimenting with the search engine optimization query results page. Strategic placement of keywords and even phrases, as well as fragmentation of the post's material, can improve the website's visibility to search engines. Hyperlinks open a chain reaction of additional links and draw attention to the previous posts. Publications in printed periodicals are a substantial part of a niche website presence on the Internet. Although this article explores a laboratory website on the basis of our hands-on expertise maintaining “Grossing Technology in Surgical Pathology” (www.grossing-technology.com) website with a high volume of traffic for more than a decade, the recommendations presented here for developing an authority website can be applied to other professional specialized websites. The authority websites visibility and sustainability are preconditions for aggregating them in a specialized educational laboratory portal. PMID:27688928

  4. Experience of maintaining laboratory educational website's sustainability.

    Science.gov (United States)

    Dimenstein, Izak B

    2016-01-01

    Laboratory methodology websites are specialized niche websites. The visibility of a niche website transforms it into an authority site on a particular "niche of knowledge." This article presents some ways in which a laboratory methodology website can maintain its sustainability. The optimal composition of the website includes a basic content, a blog, and an ancillary part. This article discusses experimenting with the search engine optimization query results page. Strategic placement of keywords and even phrases, as well as fragmentation of the post's material, can improve the website's visibility to search engines. Hyperlinks open a chain reaction of additional links and draw attention to the previous posts. Publications in printed periodicals are a substantial part of a niche website presence on the Internet. Although this article explores a laboratory website on the basis of our hands-on expertise maintaining "Grossing Technology in Surgical Pathology" (www.grossing-technology.com) website with a high volume of traffic for more than a decade, the recommendations presented here for developing an authority website can be applied to other professional specialized websites. The authority websites visibility and sustainability are preconditions for aggregating them in a specialized educational laboratory portal.

  5. Identification of methanogenic pathways in anaerobic digesters using stable carbon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Laukenmann, Stephan; Polag, Daniela; Greule, Markus; Lelieveld, Jos; Keppler, Frank [Max-Planck-Institut fuer Chemie, Mainz (Germany); Heuwinkel, Hauke; Gronauer, Andreas [Landesanstalt fuer Landwirtschaft, Freising (Germany)

    2010-12-15

    In a series of anaerobic batch experiments, the stable carbon isotopes, {delta}{sup 13}C{sub CH4} and {delta}{sup 13}C{sub CO2}, were measured in biogas produced from various sources (maize, cellulose, inoculum) to identify the degradation kinetics and specific methanogenic pathways. Isotopic analysis was performed using a new absorption laser spectrometer in addition to conventional MS. A comparison of the isotopic evolution shows large isotope dynamics for maize and cellulose, indicating a temporal change in degradation pathways and/or a change in the relative contribution from different carbon fractions within the substrate. Further batch experiments with isotopically labelled acetate (either {sup 13}CH{sub 3}CO{sub 2}Na or CH{sup 13}{sub 3}CO{sub 2}Na) were carried out to study the degradation of acetate in inoculum systematically. The results suggest that the acetate is completely oxidized into CO{sub 2} which in turn is partly reduced to CH{sub 4}. Furthermore, the distinct isotopic signature CH{sub 4} and CO{sub 2} (for acetate-methyl labelling as well as for acetate-carboxy labelling) indicate that only a minor part of the produced methane derives from acetate. A substantial fraction of methane may have been produced at an earlier stage of the reaction chain or by other potential methane precursors such as formate or methanol. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Alkali elemental and potassium isotopic compositions of Semarkona chondrules

    Science.gov (United States)

    Alexander, C.M. O'D.; Grossman, J.N.

    2005-01-01

    We report measurements of K isotope ratios in 28 Semarkona chondrules with a wide range of petrologic types and bulk compositions as well as the compositions of CPX-mesostasis pairs in 17 type I Semarkona chondrules, including two chondrules with radial alkali zonation and 19 type II chondrules. Despite the wide range in K/Al ratios, no systematic variations in K isotopic compositions were found. Semarkona chondrules do not record a simple history of Rayleigh-type loss of K. Experimentally determined evaporation rates suggest that considerable alkali evaporation would have occurred during chondrule formation. Nevertheless, based on Na CPX-mesostasis distribution coefficients, the alkali contents of the cores of most chondrules in Semarkona were probably established at the time of final crystallization. However, Na CPX-mesostasis distribution coefficients also show that alkali zonation in type I Semarkona chondrules was produced by entry of alkalis after solidification, probably during parent body alteration. This alkali metasomatism may have gone to completion in some chondrules. Our preferred explanation for the lack of systematic isotopic enrichments, even in alkali depleted type I chondrule cores, is that they exchanged with the ambient gas as they cooled. ?? The Meteoritical Society, 2005.

  7. Competition from Isotopic Modelling

    Directory of Open Access Journals (Sweden)

    Virginie Fabre

    2011-01-01

    Full Text Available During later MOIS3, in Europe two populations were present, autochthonous Neanderthals and modern humans. Ecological competition between these two populations has often been evoked but never demonstrated. Our aim is to establish whether resource competition occurred. In this paper, in order to examine the possibility of ecological competition between these two populations, 599 isotopic data were subjected to rigorous statistical treatment and analysis through mixing models. The aim of this paper was to compare dietary strategies of Neanderthals and modern humans over time. Our conclusions suggest that Neanderthals and modern humans shared dietary habits in the particular environmental context of MOIS3 characterised in Europe by climatic deterioration. In this environmental context, the resource competition between Neanderthals and modern humans may have accelerated the disappearance of the Neanderthal population.

  8. Isotope Effects in ESR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Werner Herrmann

    2013-06-01

    Full Text Available In order to present the relationship between ESR spectroscopy and isotope effects three levels are considered: (i ESR spectroscopy is described on a general level up to the models for interpretation of the experimental spectra, which go beyond the usually used time and mass independent spin-Hamilton operator, (ii the main characteristics of the generalized isotope effects are worked out, and finally (iii the basic, mainly quantum mechanical effects are used to describe the coupling of electron spins with the degrees of freedom, which are accessible under the selected conditions, of the respective paramagnetic object under investigation. The ESR parameters and the respective models are formalized so far, that they include the time and mass depending influences and reflect the specific isotope effects. Relations will be established between the effects in ESR spectra to spin relaxation, to spin exchange, to the magnetic isotope effect, to the Jahn-Teller effects, as well as to the influence of zero-point vibrations. Examples will be presented which demonstrate the influence of isotopes as well as the kind of accessible information. It will be differentiated with respect to isotope effects in paramagnetic centres itself and in the respective matrices up to the technique of ESR imaging. It is shown that the use of isotope effects is indispensable in ESR spectroscopy.

  9. Boron isotopic compositions of some boron minerals

    Energy Technology Data Exchange (ETDEWEB)

    Oi, Takao; Musashi, Masaaki; Ossaka, Tomoko; Kakihana, Hidetake (Sophia Univ., Tokyo (Japan)); Nomura, Masao; Okamoto, Makoto (Tokyo Institute of Technology (Japan))

    1989-12-01

    Boron minerals that have different structural formulae but are supposed to have the same geologic origin have been collected and analyzed for the {sup 11}B/{sup 10}B isotopic ratio. It has been reconfirmed that minerals of marine origin have higher {sup 11}B/{sup 10}B ratios than those of nonmarine origin. It has been found that the sequence of decreasing {sup 11}B/{sup 10}B values among the minerals with the same geologic origin is; borax, tincal, kernite (Na borates) > ulexite (Na/Ca borate) > colemanite, iyoite, meyerhofferite (Ca borates). This sequence is explainable on the basis of the difference in crystal structure among the minerals. That is, minerals with high BO{sub 3}/BO{sub 4} ratios, (the ratio of the number of the BO{sub 3} triangle units to the number of the BO{sub 4} tetrahedron units in the structural formula of a mineral) have higher {sup 11}B/{sup 10}B ratios.

  10. Isotope and chemical geothermometry and its applications

    Institute of Scientific and Technical Information of China (English)

    庞忠和

    2001-01-01

    The Na-K-Mg Geoindicator created by Giggenbach (1988) is convenient to use but it is still based on the empirical geothermometry equations and discrepancy for different cation geo-thermometers is observed. In fact, the location of the curve of "full equilibrium" is different if a different Na-K geothermometry equation is used. The difference is pronounced for temperatures lower than about 220℃. A case study on the Zhangzhou geothermal field of SE China resulted in a reliable estimate of reservoir temperature of 150℃ by the SO4-H2O pair Oxygen-18 isotope geothermometer. This has provided an example of attained equilibrium of the marine sulphate in the geothermal system in the low-medium temperature range (<150℃). A recent refinement of the theoretical geothermometry was achieved by the FixAl method, which provides the possibility to identify and solve problems such as an erroneous analytical value of Aluminium, and influence of processes such as mixing and degassing, and therefore makes it possible to

  11. Isotopic insights into microbial sulfur cycling in oil reservoirs

    Directory of Open Access Journals (Sweden)

    Christopher G Hubbard

    2014-09-01

    Full Text Available Microbial sulfate reduction in oil reservoirs (biosouring is often associated with secondary oil production where seawater containing high sulfate concentrations (~28 mM is injected into a reservoir to maintain pressure and displace oil. The sulfide generated from biosouring can cause corrosion of infrastructure, health exposure risks, and higher production costs. Isotope monitoring is a promising approach for understanding microbial sulfur cycling in reservoirs, enabling early detection of biosouring, and understanding the impact of souring. Microbial sulfate reduction is known to result in large shifts in the sulfur and oxygen isotope compositions of the residual sulfate, which can be distinguished from other processes that may be occurring in oil reservoirs, such as precipitation of sulfate and sulfide minerals. Key to the success of this method is using the appropriate isotopic fractionation factors for the conditions and processes being monitored. For a set of batch incubation experiments using a mixed microbial culture with crude oil as the electron donor, we measured a sulfur fractionation factor for sulfate reduction of -30‰. We have incorporated this result into a simplified 1D reservoir reactive transport model to highlight how isotopes can help discriminate between biotic and abiotic processes affecting sulfate and sulfide concentrations. Modeling results suggest that monitoring sulfate isotopes can provide an early indication of souring for reservoirs with reactive iron minerals that can remove the produced sulfide, especially when sulfate reduction occurs in the mixing zone between formation waters containing elevated concentrations of volatile fatty acids and injection water containing elevated sulfate. In addition, we examine the role of reservoir thermal, geochemical, hydrological, operational and microbiological conditions in determining microbial souring dynamics and hence the anticipated isotopic signatures.

  12. Isotope-edited infrared spectroscopy.

    Science.gov (United States)

    Buchner, Ginka S; Kubelka, Jan

    2012-01-01

    Isotope-edited infrared (IR) spectroscopy is a powerful tool for studying structural and dynamical properties of peptides and proteins with site-specific resolution. Labeling of selected amide carbonyls with (13)C results in detectable sidebands of amide I' vibrations, which provide information about local conformation and/or solvent exposure without structural perturbation to the protein. Incorporation of isotopically labeled amino acids at specific positions is achieved by the chemical synthesis of the studied proteins. We describe the basic procedures for synthesis of (13)C isotopically edited protein samples, experimental IR spectroscopic measurements, and analysis of the site-specific structural changes from the thermal unfolding IR data.

  13. Compelling Research Opportunities using Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-04-23

    Isotopes are vital to the science and technology base of the US economy. Isotopes, both stable and radioactive, are essential tools in the growing science, technology, engineering, and health enterprises of the 21st century. The scientific discoveries and associated advances made as a result of the availability of isotopes today span widely from medicine to biology, physics, chemistry, and a broad range of applications in environmental and material sciences. Isotope issues have become crucial aspects of homeland security. Isotopes are utilized in new resource development, in energy from bio-fuels, petrochemical and nuclear fuels, in drug discovery, health care therapies and diagnostics, in nutrition, in agriculture, and in many other areas. The development and production of isotope products unavailable or difficult to get commercially have been most recently the responsibility of the Department of Energy's Nuclear Energy program. The President's FY09 Budget request proposed the transfer of the Isotope Production program to the Department of Energy's Office of Science in Nuclear Physics and to rename it the National Isotope Production and Application program (NIPA). The transfer has now taken place with the signing of the 2009 appropriations bill. In preparation for this, the Nuclear Science Advisory Committee (NSAC) was requested to establish a standing subcommittee, the NSAC Isotope Subcommittee (NSACI), to advise the DOE Office of Nuclear Physics. The request came in the form of two charges: one, on setting research priorities in the short term for the most compelling opportunities from the vast array of disciplines that develop and use isotopes and two, on making a long term strategic plan for the NIPA program. This is the final report to address charge 1. NSACI membership is comprised of experts from the diverse research communities, industry, production, and homeland security. NSACI discussed research opportunities divided into three areas: (1

  14. Carbon isotope geochemistry and geobiology

    Science.gov (United States)

    Desmarais, D.

    1985-01-01

    Carbon isotope fractionation values were used to understand the history of the biosphere. For example, plankton analyses confirmed that marine extinctions at the end of the Cretaceous period were indeed severe (see Hsu's article in Sundquist and Broeker, 1984). Variations in the isotopic compositions of carbonates and evaporitic sulfates during the Paleozoic reflect the relative abundances of euxinic (anoxic) marine environments and organic deposits from terrestrial flora. The carbon isotopic composition of Precambrian sediments suggest that the enzyme ribulose bisphosphate carboxylase has existed for perhaps 3.5 billion years.

  15. Ethylene and nitric oxide are involved in maintaining ion homeostasis in Arabidopsis callus under salt stress.

    Science.gov (United States)

    Wang, Huahua; Liang, Xiaolei; Wan, Qi; Wang, Xiaomin; Bi, Yurong

    2009-07-01

    In the present study, the role of ethylene in nitric oxide (NO)-mediated protection by modulating ion homeostasis in Arabidopsis callus under salt stress was investigated. Results showed that the ethylene-insensitive mutant etr1-3 was more sensitive to salt stress than the wild type (WT). Under 100 mM NaCl, etr1-3 callus displayed a greater electrolyte leakage and Na(+)/K(+) ratio but a lower plasma membrane (PM) H(+)-ATPase activity compared to WT callus. Application of exogenous 1-aminocyclopropane-1-carboxylic acid (ACC, an ethylene precursor) or sodium nitroprusside (SNP, a NO donor) alleviated NaCl-induced injury by maintaining a lower Na(+)/K(+) ratio and an increased PM H(+)-ATPase activity in WT callus but not in etr1-3 callus. The SNP actions in NaCl stress were attenuated by a specific NO scavenger or an ethylene biosynthesis inhibitor in WT callus. Under 100 mM NaCl, the NO accumulation and ethylene emission appeared at early time, and NO production greatly stimulated ethylene emission in WT callus. In addition, ethylene induced the expression of PM H(+)-ATPase genes under salt stress. The recovery experiment showed that NaCl-induced injury was reversible, as signaled by the similar recovery of Na(+)/K(+) ratio and PM H(+)-ATPase activity in WT callus. Taken together, the results indicate that ethylene and NO cooperate in stimulating PM H(+)-ATPase activity to modulate ion homeostasis for salt tolerance, and ethylene may be a part of the downstream signal molecular in NO action.

  16. Maintaining the Telescope Bibliography at Gemini Observatory

    Science.gov (United States)

    Zhang, X.

    2010-10-01

    The library profession benefits tremendously from ever-changing web technologies. In maintaining a telescope bibliography, web-publishing revolutionized the way librarians track relevant publications. Thanks to the search abilities provided by the NASA Astrophysics Data System, arXiv, publishers, as well as Google Scholar, and other such resources, online searching for Gemini-based publications has replaced the tedious perusing of print journals. However, we should keep in mind that online searching is neither flawless nor simple — different content providers require different search strategies. Sometimes the retrievals are not as complete as one expects. Information providers should be constantly improving their searching abilities in order to make the task of electronic publication tracking more reliable and efficient.

  17. [Maintaining solidarity: is mutuality the solution?].

    Science.gov (United States)

    Gevers, J K M; Ploem, M C

    2013-01-01

    Solidarity is essentially the willingness to contribute to the community and its demands, which may even involve contributing more than one is expecting to receive. Another principle is mutuality: this refers to a balance between rights and obligations or between mutual obligations. In its advisory document 'The importance of mutuality......solidarity takes work!', The Dutch Council for Public Health and Health Care underlines the importance of ensuring solidarity within the Dutch health care system, e.g. by encouraging patients to take responsibility for their own health, possibly by introducing elements of mutuality. In our contribution, we comment on the Council's advice. Although we fully agree with the overall conclusion that solidarity should be maintained within the system, we do not see how the introduction of increased mutuality will contribute to this goal.

  18. Maintaining and troubleshooting your 3D printer

    CERN Document Server

    Bell, Charles

    2014-01-01

    Maintaining and Troubleshooting Your 3D Printer by Charles Bell is your guide to keeping your 3D printer running through preventive maintenance, repair, and diagnosing and solving problems in 3D printing. If you've bought or built a 3D printer such as a MakerBot only to be confounded by jagged edges, corner lift, top layers that aren't solid, or any of a myriad of other problems that plague 3D printer enthusiasts, then here is the book to help you get past all that and recapture the joy of creative fabrication. The book also includes valuable tips for builders and those who want to modify the

  19. Motives for maintaining personal journal blogs.

    Science.gov (United States)

    Hollenbaugh, Erin E

    2011-01-01

    Although much has been learned about political and news blogs, there has been a lack of research on personal journal blogs. They deserve further research attention because of the implications blogs have in many bloggers' immediate social networks, as well as the opportunities for scientific inquiry in a rich and evolving communication environment. This study explored bloggers' motives for maintaining personal journal blogs, or blogs that resemble diaries about one's personal life. Stemming from the uses and gratifications perspective, antecedents (age, sex, loneliness, disclosiveness) and blogging motives composed a model for predicting the amount of blog use. Seven motives emerged from online survey data: helping/informing, social connection, pass time, exhibitionism, archiving/organizing, professionalism, and get feedback. Age, sex, loneliness, and disclosiveness predicted different motives, and the total model (age, sex, loneliness, disclosiveness, and motives) was useful for explaining 13% of the variance in the amount of blog use.

  20. Heartwarming memories: Nostalgia maintains physiological comfort.

    Science.gov (United States)

    Zhou, Xinyue; Wildschut, Tim; Sedikides, Constantine; Chen, Xiaoxi; Vingerhoets, Ad J J M

    2012-08-01

    Nostalgia, a sentimental longing or wistful affection for the past, is a predominantly positive and social emotion. Recent evidence suggests that nostalgia maintains psychological comfort. Here, we propose, and document in five methodologically diverse studies, a broader homeostatic function for nostalgia that also encompasses the maintenance of physiological comfort. We show that nostalgia--an emotion with a strong connotation of warmth--is triggered by coldness. Participants reported stronger nostalgia on colder (vs. warmer) days and in a cold (vs. neutral or warm) room. Nostalgia, in turn, modulates the interoceptive feeling of temperature. Higher levels of music-evoked nostalgia predicted increased physical warmth, and participants who recalled a nostalgic (vs. ordinary autobiographical) event perceived ambient temperature as higher. Finally, and consistent with the close central nervous system integration of temperature and pain sensations, participants who recalled a nostalgic (vs. ordinary autobiographical) event evinced greater tolerance to noxious cold.

  1. How homologous recombination maintains telomere integrity.

    Science.gov (United States)

    Tacconi, Eliana M C; Tarsounas, Madalena

    2015-06-01

    Telomeres protect the ends of linear chromosomes against loss of genetic information and inappropriate processing as damaged DNA and are therefore crucial to the maintenance of chromosome integrity. In addition to providing a pathway for genome-wide DNA repair, homologous recombination (HR) plays a key role in telomere replication and capping. Consistent with this, the genomic instability characteristic of HR-deficient cells and tumours is driven in part by telomere dysfunction. Here, we discuss the mechanisms by which HR modulates the response to intrinsic cellular challenges that arise during telomere replication, as well as its impact on the assembly of telomere protective structures. How normal and tumour cells differ in their ability to maintain telomeres is deeply relevant to the search for treatments that would selectively eliminate cells whose capacity for HR-mediated repair has been compromised.

  2. Apparatus and process for separating hydrogen isotopes

    Science.gov (United States)

    Heung, Leung K; Sessions, Henry T; Xiao, Xin

    2013-06-25

    The apparatus and process for separating hydrogen isotopes is provided using dual columns, each column having an opposite hydrogen isotopic effect such that when a hydrogen isotope mixture feedstock is cycled between the two respective columns, two different hydrogen isotopes are separated from the feedstock.

  3. Maintaining control is team's vital role.

    Science.gov (United States)

    Haywood, Liz; Frankel, Chris; Johns, Andrew

    2011-02-01

    In an environment where there is an ever-increasing use of reliable electronic control, it is easy to become complacent about the need for in-depth knowledge of how the controls actually work. After all, experts who can diagnose and fix such systems are only a phone call away, and a new unit can easily be fitted. Sometimes this is not the case at Bendigo Health, as we have a number of systems with a "black box" set of controls that can take days, or weeks, to fix, and cannot be fixed locally. To better manage and maintain our infrastructure, the Buildings & Infrastructure Department at Bendigo Health includes a number of employees who concentrate on building management systems (BMS). The BMS group plays a vital role in the complete lifecycle of projects that include control and monitoring of the plant within the hospital setting. A good example of this role was in the design, build, installation and commissioning, of two new negative pressure suites at Bendigo Health. The BMS group's involvement in this particular project included the door interlocking, the air conditioning and exhaust fan control, and a comprehensive alarm panel and overrides, all of which can be monitored centrally via the existing BMS system. The involvement of the BMS group, following the DHS guidelines, resulted in the architect and consulting engineers revisiting their designs and improving them to the benefit of both patient care and staff safety. The advantages of projects such as the negative pressure suites installed by the BMS group include the fact that that the hospital gains facilities that work correctly and according to industry guidelines; and the design, installation, and controls of the plant are understood by the people who will be maintaining the infrastructure. This paper will provide an overview of the work undertaken by the BMS group at Bendigo Health, using the negative pressure suites as an exemplar.

  4. The evolution of Carbon isotopes in calcite in the presence of cyanobacteria

    Science.gov (United States)

    Grimm, Christian; Mavromatis, Vasileios; Pokrovsky, Oleg S.; Oelkers, Eric H.

    2016-04-01

    Stable isotopic compositions in carbonates are widely used as indicators of environmental conditions prevailing during mineral formation. This reconstruction is substantially based on the assumption that there is no change in the mineral composition over geological time. However, recent experimental studies have shown that carbon and magnesium isotopes in hydrous Mg-carbonates undergo continuous re-equilibration with the ambient solution even after mineral precipitation stopped ([1] and [2], respectively). To verify whether this holds true for anhydrous Ca-bearing carbonates which readily form at earth's surface environments, a series of batch system calcite precipitation experiments were performed in the presence of actively growing cyanobacteria Synechococcus sp. The bacteria were grown at ambient temperature in a BG11 culture medium (SIGMA C3061) and continuous stirring, air-bubbling and illumination. Calcite precipitation was initiated by the addition of 8.5mM CaCl2 and 0-50 mM NaHCO3 or NaHCO3-Na2CO3 mixtures. The presence of cyanobacteria is on one hand promoting CaCO3 formation due to increasing pH resulting from photosynthesis. On the other hand, actively growing cyanobacteria drastically change carbon isotope signature of the aqueous fluid phase by preferably incorporating the lighter 12C isotope into biomass [1]. This study explores the effect of continuously changing carbon isotope compositions in dissolved inorganic carbon (DIC) on precipitated calcite which is in chemical equilibrium with the ambient fluid phase. [1] Mavromatis et al. (2015). The continuous re-equilibration of carbon isotope compositions of hydrous Mg-carbonates in the presence of cyanobacteria. Chem. Geol. 404, 41-51 [2] Mavromatis et al. (2012). Magnesium isotope fractionation during hydrous magnesium carbonate precipitation with and without cyanobacteria. Geochim. Cosmochim. Acta 76, 161-174

  5. The quantum and mechanical justification of intensification by magnetic field of amalgam isotope separation method

    Directory of Open Access Journals (Sweden)

    Myshkin V. F.

    2015-09-01

    Full Text Available The steady increase in demand for isotopes requires the development of methods to increase the efficiency of isotope separation technologies. Methods of isotope separation based on thermodynamic differences of isotopic forms of the molecules don't require significant investment, but characterized by a low rate of exchange. It's known that the magnetic effect leads to a change the vibrational frequency of the molecules, and therefore their thermodynamic parameters. The change increases the thermodynamic parameters, including the exchange rate. The results of the experimental determination of the thermal effect of dissolving the salts of NaCl, KCl, CuSO4, sodium amalgam decomposition by distillate in a magnetic field and without field were shown. Magnetic interference can have a significant effect on the amalgam exchange method which was shown by quantum and mechanical analysis of the results

  6. The production of ultra-high purity single isotopes or tailored isotope mixtures by ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Liezers, Martin; Farmer, Orville T.; Dion, Michael P.; Thomas, Linda MP; Eiden, Gregory C.

    2015-01-01

    We report the development and testing of a simple collector arrangement for a commercial quadrupole ICP-MS that for the first time has been used to produce small quantities of highly enriched (>99.99%) single isotopes, with deposition rates >10 ng/hour. The collector assembly replaces the standard instrument detector allowing for implantation with simultaneous monitoring of the incident ion current. Even under zero bias implant conditions, low energy (<10 eV), ion collection efficiency was observed to be very high ~99%. 151Eu ion currents of 0.1-0.5 nA were collected on a simple, planar foil without resorting to any type of cup configuration. Recovery of the enriched isotope from such foils is much simpler than from a more complex cup configuration. High rejection of adjacent mass isotopes was demonstrated by selectively implanting 167Er without any discernible co-implantation of 166Er and 168Er. The important analytical possibilities of the new approach to isotope ratio measurement, tracer purification and radiation measurements are discussed.

  7. Central role of the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) in sodium bioenergetics of Vibrio cholerae.

    Science.gov (United States)

    Steuber, Julia; Halang, Petra; Vorburger, Thomas; Steffen, Wojtek; Vohl, Georg; Fritz, Günter

    2014-12-01

    Vibrio cholerae is a Gram-negative bacterium that lives in brackish or sea water environments. Strains of V. cholerae carrying the pathogenicity islands infect the human gut and cause the fatal disease cholera. Vibrio cholerae maintains a Na(+) gradient at its cytoplasmic membrane that drives substrate uptake, motility, and efflux of antibiotics. Here, we summarize the major Na(+)-dependent transport processes and describe the central role of the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR), a primary Na(+) pump, in maintaining a Na(+)-motive force. The Na(+)-NQR is a membrane protein complex with a mass of about 220 kDa that couples the exergonic oxidation of NADH to the transport of Na(+) across the cytoplasmic membrane. We describe the molecular architecture of this respiratory complex and summarize the findings how electron transport might be coupled to Na(+)-translocation. Moreover, recent advances in the determination of the three-dimensional structure of this complex are reported.

  8. Isotope separation with the RICH detector of the AMS Experiment

    CERN Document Server

    Arruda, Luísa; Borges, João; Carmo, Fernando; Gonçalves, Patrícia; Pereira, Rui; Pimenta, Mário

    2007-01-01

    The Alpha Magnetic Spectrometer (AMS), to be installed on the International Space Station (ISS) in 2008, is a cosmic ray detector with several subsystems, one of which is a proximity focusing Ring Imaging Cherenkov (RICH) detector. This detector will be equipped with a dual radiator (aerogel+NaF), a lateral conical mirror and a detection plane made of 680 photomultipliers and light guides, enabling precise measurements of particle electric charge and velocity. Combining velocity measurements with data on particle rigidity from the AMS Tracker it is possible to obtain a measurement for particle mass, allowing the separation of isotopes. A Monte Carlo simulation of the RICH detector, based on realistic properties measured at ion beam tests, was performed to evaluate isotope separation capabilities. Results for three elements -- H (Z=1), He (Z=2) and Be (Z=4) -- are presented.

  9. Lattice sites of Na dopants in ZnO

    CERN Document Server

    AUTHOR|(CDS)2069243; Martins Correia, Joao; Amorim, Lígia; Decoster, Stefan; Ribeiro da Silva, Manuel; Da Costa Pereira, Lino Miguel

    2016-01-01

    The angular distribution of beta− particles emitted by the radioactive isotope 24Na was monitored following implantation into ZnO single crystals at fluences above 5E12 cm−2 at CERN’s ISOLDE facility. We identified sodium on two distinct sites: on substitutional Zn sites and on interstitial sites that are close to the so-called octahedral site. The interstitial Na was to large extent converted to substitutional Na already for annealing at 200°C, from which an activation energy of 0.8−1.3 eV, most likely around 1.2 eV, is estimated for the migration of interstitial Na in ZnO.

  10. Lattice sites of Na dopants in ZnO

    Science.gov (United States)

    Wahl, U.; Correia, J. G.; Amorim, L.; Decoster, S.; da Silva, M. R.; Pereira, L. M. C.

    2016-09-01

    The angular distribution of β - particles emitted by the radioactive isotope 24Na was monitored following implantation into ZnO single crystals at fluences above 5 × 1012 cm-2 at CERN’s ISOLDE facility. We identified sodium on two distinct sites: on substitutional Zn sites and on interstitial sites that are close to the so-called octahedral site. The interstitial Na was to a large extent already converted to substitutional Na for annealing at 200 °C, from which an activation energy of 0.8-1.3 eV, most likely around 1.2 eV, is estimated for the migration of interstitial Na in ZnO.

  11. Alignments in the nobelium isotopes

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Zie; XU Fu-Rong; YUAN Cen-Xi; QI Chong

    2009-01-01

    Total-Routhian-Surface calculations have been performed to investigate the deformation and align-ment properties of the No isotopes. It is found that normal deformed and superdeformed states in these nuclei can coexist at low excitation energies. In neutron-deficient No isotopes, the superdeformed shapes can even become the ground states. Moreover, we plotted the kinematic moments of inertia of the No isotopes, which follow very nicely available experimental data. It is noted that, as the rotational frequency increases, align-ments develop at hω=0.2-0.3 MeV. Our calculations show that the occupation of the vj orbital plays an important role in the alignments of the No isotopes.

  12. Isotope-based quantum information

    CERN Document Server

    G Plekhanov, Vladimir

    2012-01-01

    The present book provides to the main ideas and techniques of the rapid progressing field of quantum information and quantum computation using isotope - mixed materials. It starts with an introduction to the isotope physics and then describes of the isotope - based quantum information and quantum computation. The ability to manipulate and control electron and/or nucleus spin in semiconductor devices provides a new route to expand the capabilities of inorganic semiconductor-based electronics and to design innovative devices with potential application in quantum computing. One of the major challenges towards these objectives is to develop semiconductor-based systems and architectures in which the spatial distribution of spins and their properties can be controlled. For instance, to eliminate electron spin decoherence resulting from hyperfine interaction due to nuclear spin background, isotopically controlled devices are needed (i.e., nuclear spin-depleted). In other emerging concepts, the control of the spatial...

  13. Isotopic Changes During Digestion: Protein

    Science.gov (United States)

    Tuross, N.

    2013-12-01

    Nutrient and hydrological inputs traverse a complicated route of pH, enzymatic and cellular processes in digestion in higher animals. The end products of digestion are the starting products for biosynthesis that are often used to interpret past life-ways. Using an artificial gut system, the isotopic changes (dD, d18O, d13C and d15N) of protein are documented. Three separate protein sources are subjected to the conditions, chemical and enzymatic, found in the stomach and upper small intestine with only a small shift in the oxygen isotopic composition of the proteins observed. Middle to lower small intestine parameters produced both greater isotopic effects and significantly lower molecular weight products. The role of the gastric enterocyte and the likely involvement of the internal milieu of this cell in the isotopic composition of amino acids that are transported to the liver are reported.

  14. Shallow groundwater from the far north of Cameroon (southern Lake Chad): revisiting a 20 years old survey of hydrochemistry and stable isotopes

    Science.gov (United States)

    Ketchemen-Tandia, Beatrice; Mohammad, Bello; Fouepe, Alain; Ngo Boum, Suzanne; Nlend, Bertil; Garel, Emilie; Celle-Jeanton, Helene; Huneau, Frederic

    2016-04-01

    Two field hydrogeological investigation surveys were conducted in 1992 and 2013 using hydrochemistry and isotope techniques in the far north part of Cameroon which corresponds to the southern part of Lake Chad basin. All of these data relate to groundwater and surface water which were collected at the same places to potentially reveal any temporal variation in the chemical and isotopic characteristics of the water resources. Groundwater show mainly a Ca-HCO3 water type but CaMg-Cl and Na-HCO3 water types can also be found. The groundwater chemistry is resulting from many processes including pure silicate weathering and cation exchange. It is found that the nitrate content after 20 years has increased by an average factor of 6. These high concentrations in nitrate (up to 400 mg/l) are related to local anthropogenic activities and to the very bad conditions of maintaining of wells and boreholes. This pollution is also correlated to the population growth over the past two decades in the region. The isotopic content of groundwater is ranging from -6.87‰ to -0.32‰ for δ18O in 2013 and from -6.03‰ to +0.25‰ in 1992 without noticeable evolution through time. The conventional δD-δ18O diagram indicates that the groundwater has a meteoric origin more or less influenced by evaporation processes. Different processes involving different water sources were highlighted: (i) groundwater which has been affected by evaporation or in communication with evaporated surface waters; (ii) groundwater which is very close to the Global Meteoric Water Line and corresponding to a recent and direct recharge from precipitation; (iii) groundwater which is more depleted corresponding to a mixing between shallow and deep groundwater. This research is partly supported by the RAF7012and RAF7011 project from IAEA.

  15. Research and application of method of oxygen isotope of inorganic phosphate in Beijing agricultural soils.

    Science.gov (United States)

    Tian, Liyan; Guo, Qingjun; Zhu, Yongguan; He, Huijun; Lang, Yunchao; Hu, Jian; Zhang, Han; Wei, Rongfei; Han, Xiaokun; Peters, Marc; Yang, Junxing

    2016-12-01

    Phosphorus (P) in agricultural ecosystems is an essential and limited element for plants and microorganisms. However, environmental problems caused by P accumulation as well as by P loss have become more and more serious. Oxygen isotopes of phosphate can trace the sources, migration, and transformation of P in agricultural soils. In order to use the isotopes of phosphate oxygen, appropriate extraction and purification methods for inorganic phosphate from soils are necessary. Here, we combined two different methods to analyze the oxygen isotopic composition of inorganic phosphate (δ(18)OP) from chemical fertilizers and different fractions (Milli-Q water, 0.5 mol L(-1) NaHCO3 (pH = 8.5), 0.1 mol L(-1) NaOH and 1 mol L(-1) HCl) of agricultural soils from the Beijing area. The δ(18)OP results of the water extracts and NaHCO3 extracts in most samples were close to the calculated equilibrium value. These phenomena can be explained by rapid P cycling in soils and the influence of chemical fertilizers. The δ(18)OP value of the water extracts and NaHCO3 extracts in some soil samples below the equilibrium value may be caused by the hydrolysis of organic P fractions mediated by extracellular enzymes. The δ(18)OP values of the NaOH extracts were above the calculated equilibrium value reflecting the balance state between microbial uptake of phosphate and the release of intracellular phosphate back to the soil. The HCl extracts with the lowest δ(18)OP values and highest phosphate concentrations indicated that the HCl fraction was affected by microbial activity. Hence, these δ(18)Op values likely reflected the oxygen isotopic values of the parent materials. The results suggested that phosphate oxygen isotope analyses could be an effective tool in order to trace phosphate sources, transformation processes, and its utilization by microorganisms in agricultural soils.

  16. Accurate and precise zinc isotope ratio measurements in urban aerosols.

    Science.gov (United States)

    Gioia, Simone; Weiss, Dominik; Coles, Barry; Arnold, Tim; Babinski, Marly

    2008-12-15

    We developed an analytical method and constrained procedural boundary conditions that enable accurate and precise Zn isotope ratio measurements in urban aerosols. We also demonstrate the potential of this new isotope system for air pollutant source tracing. The procedural blank is around 5 ng and significantly lower than published methods due to a tailored ion chromatographic separation. Accurate mass bias correction using external correction with Cu is limited to Zn sample content of approximately 50 ng due to the combined effect of blank contribution of Cu and Zn from the ion exchange procedure and the need to maintain a Cu/Zn ratio of approximately 1. Mass bias is corrected for by applying the common analyte internal standardization method approach. Comparison with other mass bias correction methods demonstrates the accuracy of the method. The average precision of delta(66)Zn determinations in aerosols is around 0.05 per thousand per atomic mass unit. The method was tested on aerosols collected in Sao Paulo City, Brazil. The measurements reveal significant variations in delta(66)Zn(Imperial) ranging between -0.96 and -0.37 per thousand in coarse and between -1.04 and 0.02 per thousand in fine particular matter. This variability suggests that Zn isotopic compositions distinguish atmospheric sources. The isotopic light signature suggests traffic as the main source. We present further delta(66)Zn(Imperial) data for the standard reference material NIST SRM 2783 (delta(66)Zn(Imperial) = 0.26 +/- 0.10 per thousand).

  17. C, O and Sr isotopic stratigraphy of carbonates pre and pos Jequitai glaciation: Bezerra-Formosa area, Goias, BR;Variacoes dos isotopos de C e Sr em carbonatos pre e pos-glaciacao Jequitai (Esturtiano) na regiao de Bezerra-Formosa, Goias

    Energy Technology Data Exchange (ETDEWEB)

    Alvarenga, Carlos Jose Souza de; Della Giustina, Maria Emilia Schuteski; Silva, Nivea Goulart Carramal; Santos, Roberto Ventura; Gioia, Simone Maria Costa Lima; Guimaraes, Edi Mendes; Dardenne, Marcel Auguste, E-mail: alva1@unb.b [Universidade de Brasilia (IG/UnB), DF (Brazil). Inst. de Geociencias; Sial, Alcides Nobrega; Ferreira, Valderez Pinto [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Lab. de Isotopos Estaveis (LABISE)

    2007-12-15

    Carbonate rocks of the upper Paranoa Group and lower Bambui Group (Sete Lagoas Formation) have been founded at the occidental border of the Sao Francisco craton. These units have been separated by the Sturtian glaciation, identified by Jequitai Formation, but in some localities the glacial record is absent and is difficult to separate these two carbonates units. In this paper two sections with a good stratigraphic control have been chosen to find C, O and Sr isotopic values to have tools for the correlations. Carbonates of the Paranoa Group present a trend of positive {delta}{sup 13}C{sub PDB} varying between +0.8 e +2.7 %o, of {delta}{sup 18}O{sub PDB} varying between -9.0 e -4.7 %o and {sup 87}Sr/{sup 86}Sr ranging from 0.7063 to 0.7068. The diamictite sample of Jequitai Formation has {delta}{sup 13}C{sub PDB} values of -1.8%o and {delta}{sup 18}O{sub PDB} values of -5.1%o. The cap dolomites of the Sete Lagoas Formation are associated with an extremely negative {delta}{sup 13}C{sub PDB} values between -6.0 e -3.2 %o, {delta}{sup 18}O{sub PDB} values between -9.1 e -5.3%o and high {sup 87}Sr/{sup 86}Sr ratios suggesting a radiogenic Sr isotope anomaly. Limestone and muddy-limestone above the cap dolomite still starts with extremely negative {delta}{sup 13}C{sub PDB} values (-6.0%o) and are followed by an upward trend of increasing carbon isotope values up to +9.2 %o. In the same interval the {delta}{sup 18}O{sub PDB} values ranging from -10.1%o at the base to -5.5%o in direction to the top of formation and primary {sup 87}Sr/{sup 86}Sr ratios between 0.70745 and 0.70758. The Carbon and Sr isotope data presented here reveal significant differences between carbonates from the Paranoa Group and the Bambui Group. These data developed here provides the framework for a new regional isotopic correlation model to the carbonates units of the Paranoa and Bambui groups. (author)

  18. Novel regulation of cell [Na(+)] in macula densa cells: apical Na(+) recycling by H-K-ATPase.

    Science.gov (United States)

    Peti-Peterdi, János; Bebok, Zsuzsa; Lapointe, Jean-Yves; Bell, P Darwin

    2002-02-01

    Na-K-ATPase is the nearly ubiquitous enzyme that maintains low-Na(+), high-K(+) concentrations in cells by actively extruding Na(+) in exchange for K(+). The prevailing paradigm in polarized absorbing epithelial cells, including renal nephron segments and intestine, has been that Na-K-ATPase is restricted to the basolateral membrane domain, where it plays a prominent role in Na(+) absorption. We have found, however, that macula densa (MD) cells lack functionally and immunologically detectable amounts of Na-K-ATPase protein. In fact, these cells appear to regulate their cytosolic [Na(+)] via another member of the P-type ATPase family, the colonic form of H-K-ATPase, which is located at the apical membrane in these cells. We now report that this constitutively expressed apical MD colonic H-K-ATPase can function as a Na(H)-K-ATPase and regulate cytosolic [Na(+)] in a novel manner. This apical Na(+)-recycling mechanism may be important as part of the sensor function of MD cells and represents a new paradigm in cell [Na(+)] regulation.

  19. Mental health services--maintaining strategic direction.

    Science.gov (United States)

    McFadyen, J A; Farrington, A

    1998-09-01

    AIM AND KEY ISSUES: This article reviews the theoretical basis of strategic management in an attempt to provide managers with a better understanding of the underpinning concepts and consequent actions they need to take to avoid loss of control and ultimate failure. The authors argue that community care for the severely mentally ill is failing and that in part the reason for this perceived failure is a closer allegiance to primary care that has shifted the focus away from mental illness. Such a shift, coupled with poor management and a desire by Community Mental Health Nurses (CMHNs) to retain a broad focus and maintain the 'autonomy' they gain when not held in the gravitational grasp of Consultant Psychiatrists, has resulted in strategic drift. The authors suggest 10 possible reasons to explain why CMHNs currently fail to meet the needs of the severely mentally ill. Among these are a lack of explicit strategic implementation plans, professional ambivalence and self-interest, poor management of resources and conflicting demands from key interest groups. It seems that mental health services in this country have reached the point where resistance to change should be crumbling in the face of perceived failure to deliver the required services. Whilst it could be argued that a major and potent source of internal change is performance gaps, few things force change more than sudden and unexpected information about poor organizational performance.

  20. Arteriolar niches maintain haematopoietic stem cell quiescence

    Science.gov (United States)

    Kunisaki, Yuya; Bruns, Ingmar; Scheiermann, Christoph; Ahmed, Jalal; Pinho, Sandra; Zhang, Dachuan; Mizoguchi, Toshihide; Wei, Qiaozhi; Lucas, Daniel; Ito, Keisuke; Mar, Jessica C.; Bergman, Aviv; Frenette, Paul S.

    2013-01-01

    Cell cycle quiescence is a critical feature contributing to haematopoietic stem cell (HSC) maintenance. Although various candidate stromal cells have been identified as potential HSC niches, the spatial localization of quiescent HSCs in the bone marrow (BM) remains unclear. Here, using a novel approach that combines whole-mount confocal immunofluorescence imaging techniques and computational modelling to analyse significant tridimensional associations among vascular structures, stromal cells and HSCs, we show that quiescent HSCs associate specifically with small arterioles that are preferentially found in endosteal BM. These arterioles are ensheathed exclusively by rare NG2+ pericytes, distinct from sinusoid-associated LepR+ cells. Pharmacological or genetic activation of HSC cell cycle alters the distribution of HSCs from NG2+ peri-arteriolar niches to LepR+ peri-sinusoidal niches. Conditional depletion of NG2+ cells induces HSC cycling and reduces functional long-term repopulating HSCs in BM. These results thus indicate that arteriolar niches are indispensable to maintain HSC quiescence. PMID:24107994

  1. MAVS maintains mitochondrial homeostasis via autophagy

    Science.gov (United States)

    Sun, Xiaofeng; Sun, Liwei; Zhao, Yuanyuan; Li, Ying; Lin, Wei; Chen, Dahua; Sun, Qinmiao

    2016-01-01

    Mitochondrial antiviral signalling protein (MAVS) acts as a critical adaptor protein to transduce antiviral signalling by physically interacting with activated RIG-I and MDA5 receptors. MAVS executes its functions at the outer membrane of mitochondria to regulate downstream antiviral signalling, indicating that the mitochondria provides a functional platform for innate antiviral signalling transduction. However, little is known about whether and how MAVS-mediated antiviral signalling contributes to mitochondrial homeostasis. Here we show that the activation of MAVS is sufficient to induce autophagic signalling, which may mediate the turnover of the damaged mitochondria. Importantly, we find MAVS directly interacts with LC3 through its LC3-binding motif ‘YxxI’, suggesting that MAVS might act as an autophagy receptor to mediate mitochondrial turnover upon excessive activation of RLR signalling. Furthermore, we provide evidence that both MAVS self-aggregation and its interaction with TRAF2/6 proteins are important for MAVS-mediated mitochondrial turnover. Collectively, our findings suggest that MAVS acts as a potential receptor for mitochondria-associated autophagic signalling to maintain mitochondrial homeostasis. PMID:27551434

  2. Arteriolar niches maintain haematopoietic stem cell quiescence.

    Science.gov (United States)

    Kunisaki, Yuya; Bruns, Ingmar; Scheiermann, Christoph; Ahmed, Jalal; Pinho, Sandra; Zhang, Dachuan; Mizoguchi, Toshihide; Wei, Qiaozhi; Lucas, Daniel; Ito, Keisuke; Mar, Jessica C; Bergman, Aviv; Frenette, Paul S

    2013-10-31

    Cell cycle quiescence is a critical feature contributing to haematopoietic stem cell (HSC) maintenance. Although various candidate stromal cells have been identified as potential HSC niches, the spatial localization of quiescent HSCs in the bone marrow remains unclear. Here, using a novel approach that combines whole-mount confocal immunofluorescence imaging techniques and computational modelling to analyse significant three-dimensional associations in the mouse bone marrow among vascular structures, stromal cells and HSCs, we show that quiescent HSCs associate specifically with small arterioles that are preferentially found in endosteal bone marrow. These arterioles are ensheathed exclusively by rare NG2 (also known as CSPG4)(+) pericytes, distinct from sinusoid-associated leptin receptor (LEPR)(+) cells. Pharmacological or genetic activation of the HSC cell cycle alters the distribution of HSCs from NG2(+) periarteriolar niches to LEPR(+) perisinusoidal niches. Conditional depletion of NG2(+) cells induces HSC cycling and reduces functional long-term repopulating HSCs in the bone marrow. These results thus indicate that arteriolar niches are indispensable for maintaining HSC quiescence.

  3. Sociable Robots through Self-maintained Energy

    Directory of Open Access Journals (Sweden)

    Henrik Schioler

    2008-11-01

    Full Text Available Research of autonomous mobile robots has mostly emphasized interaction and coordination that are natually inspired from biological behavior of birds, insects, and fish: flocking, foraging, collecting, and sharing. However, most research has been only focused on autonomous behaviors in order to perform robots like animals, whereas it is lacked of determinant to those behaviours: energy. Approaching to clusted amimal and the higher, collective and sharing food among individuals are major activity to keep society being. This paper issues an approach to sociable robots using self-maintained energy in cooperative mobile robots, which is dominantly inspired from swarm behavior of collecting and sharing food of honey-bee and ant. Autonomous mobile robots are usually equipped with a finite energy, thus they can operate in a finite time. To overcome the finitude, we describe practical deployment of mobile robots that are capable of carrying and exchanging fuel to other robots. Mechanism implementation including modular hardware and control architecture to demonstrate the capabicities of the approach is presented. Subsequently, the battery exchange algorithm basically based on probabilistic modeling of total energy on each robot located in its local vicinity is described. The paper is concluded with challenging works of chain of mobile robots, rescue, repair, and relation of heterogeneous robots.

  4. Sociable Robots Through Self-Maintained Energy

    Directory of Open Access Journals (Sweden)

    Trung Dung Ngo

    2006-12-01

    Full Text Available Research of autonomous mobile robots has mostly emphasized interaction and coordination that are natually inspired from biological behavior of birds, insects, and fish: flocking, foraging, collecting, and sharing. However, most research has been only focused on autonomous behaviors in order to perform robots like animals, whereas it is lacked of determinant to those behaviours: energy. Approaching to clusted amimal and the higher, collective and sharing food among individuals are major activity to keep society being. This paper issues an approach to sociable robots using self-maintained energy in cooperative mobile robots, which is dominantly inspired from swarm behavior of collecting and sharing food of honey-bee and ant. Autonomous mobile robots are usually equipped with a finite energy, thus they can operate in a finite time. To overcome the finitude, we describe practical deployment of mobile robots that are capable of carrying and exchanging fuel to other robots. Mechanism implementation including modular hardware and control architecture to demonstrate the capabicities of the approach is presented. Subsequently, the battery exchange algorithm basically based on probabilistic modeling of total energy on each robot located in its local vicinity is described. The paper is concluded with challenging works of chain of mobile robots, rescue, repair, and relation of heterogeneous robots.

  5. Surface area dependence of calcium isotopic reequilibration in carbonates: Implications for isotopic signatures in the weathering zone

    Science.gov (United States)

    Fernandez, N. M.; Druhan, J. L.; Potrel, A.; Jacobson, A. D.

    2016-12-01

    The concept of dynamic equilibrium carries the implicit assumption of continued isotopic exchange between a mineral and the surrounding fluid. While this effect has received much attention in the marine paleoproxy literature, it has been relatively overlooked in application to the terrestrial environment. In weathering systems, a potential consequence is that rapid reequilibration may alter or erase isotopic signatures generated during secondary mineral formation. The extent and timescale over which isotopic signatures are reset in these hydrologic systems is unknown. Using reactive transport modeling, we show isotopic reequilibration under conditions reflecting terrestrial hydrologic settings to be significant and dependent on the reactive surface area of the solid. In particular, we suggest that the non-traditional stable isotopes commonly used in application to carbonates (e.g., Ca, Mg, Sr) are sensitive to these effects due to their rapid reaction rates. We aim to characterize the dependence of Ca isotopic reequilibration on surface area during calcite precipitation via batch experiments conducted at ambient temperature over 48-hour time periods. Calcite precipitation was performed in a closed batch reactor utilizing a controlled free-drift method. The batch reactors contained mixed supersaturated solutions of CaCl2 and NaHCO3 at an initial pH of 8.54. Precipitation was initiated by seed inoculation of calcite crystals with two distinct, pre-constrained surface areas. All experiments achieved the same final state of chemical equilibrium, but as expected, the fastest approach to equilibrium occurred for experiments employing calcite seeds with the highest surface area. This implies that differences in equilibrated Ca isotope ratios (δ44/40Ca) should reflect differences in surface area. This prediction is upheld by models of the experiments, indicating a measureable difference in δ44Ca during calcite precipitation where the higher surface area corresponds to

  6. Paleoproxies: Heavy Stable Isotope Perspectives

    Science.gov (United States)

    Nagler, T. F.; Hippler, D.; Siebert, C.; Kramers, J. D.

    2002-12-01

    Recent advances in isotope ratio mass spectrometry, namely multiple collector ICP-MS and refined TIMS techniques, will significantly enhance the ability to measure heavy stable isotope fractionation, which will lead to the development of a wide array of process-identifying (bio)-geochemical tools. Thus far research in this area is not easily assessable to scientists outside the isotope field. This is due to the fact that analyzing heavy stable isotopes does not provide routine numbers which are per se true (the preciser the truer) but is still a highly experimental field. On the other hand resolving earth science problems requires specialists familiar with the environment being studied. So what is in there for paleoceanographers? In a first order approach, relating isotope variations to physical processes is straightforward. A prominent example are oxygen isotope variations with temperature. The total geological signal is of course far more complicated. At low temperatures, heavy stable isotopes variations have been reported for e.g. Ca, Cr, Fe, Cu, Zn, Mo and Tl. Fractionation mechanisms and physical parameters responsible for the observed variations are not yet resolved for most elements. Significant equilibrium isotope fractionation is expected from redox reactions of transition metals. However a difference in coordination number between two coexisting speciations of an element in the same oxidation state can also cause fractionation. Protonation of dissolved Mo is one case currently discussed. For paleoceanography studies, a principal distinction between transition metals essential for life (V to Zn plus Mo) or not will be helpful. In case of the former group, distinction between biogenic and abiogenic isotope fractionation will remain an important issue. For example, abiotic Fe redox reactions result in isotope fractionations indistinguishable in direction and magnitude from microbial effects. Only a combination of different stable isotope systems bears the

  7. Measurement of the electric quadrupole moments of $^{26-29}$Na

    CERN Document Server

    Keim, M; Klein, A; Neugart, R; Neuroth, M; Wilbert, S; Lievens, P; Vermeeren, L; Brown, B A

    2000-01-01

    The nuclear electric quadrupole moments of the isotopes $^{26}$Na, $^{27}$Na, $^{28}$Na and $^{29}$Na were measured by $\\beta$-NMR spectroscopy in single crystals of LiNbO$_3$ and NaNO$_3$. High degrees of nuclear polarization were produced by optical pumping of the sodium atoms in a fast beam with a collinear laser beam.The polarized nuclei were implanted into the crystals and NMR signals were observed in the $\\beta$-decay asymmetries. Preparatory measurements also yielded improved values for the magnetic moments of $^{27-31}$Na and confirmed the spin $I=3/2$for $^{31}$Na. The results are discussed in comparison with large-basis shell-model calculations.

  8. Efektite na prostaciklin vo tretmanot na dijabeticnata nefropatija kaj staorci

    Directory of Open Access Journals (Sweden)

    Jasmina Trojacanec

    2006-06-01

    Full Text Available Mikrovaskularnite komplikacii, a pred se dijabeticnata nefropatija, se edni od najteskite komplikacii na dijabetot, od koi vo golema mera zavisi i prognozata na dijabetot kaj ovie pacienti. Etiopatogenezata na ovaa komplikacija e multifaktorijalna i za sega se uste ne kompletno rasvetlena, a vklucuva morfoloski, patolosko-anatomski i biohemiski metabolni narusuvanja. Se smeta deka narusuvanjeto na modularnata funkcija na endoteliumot moze da bide kriticen i inicijalen faktor vo razvojot na dijabeticnite vaskularni komplikacii. Vrz osnova na farmakodinamskite efekti koi sto gi poseduva prostaciklinot (PGI2 i negovite analozi, se smeta deka istite moze da bidat korisni vo tretmanot na dijabeti~nata nefropatija. Osnovna cel na ovaa studija be{e da se procenat efektite na prostaciklin (PGI2 vo tretmanot na dijabeticnata nefropatija, eksperimentalno predizvikana so streptozocin. Kaj normotenzivni staorci od sojot Wistar, eksperimentalno bese induciran najprvin dijabet so ednokratna i.p. administracija na streptozocin (STZ, a kako komplikacija na dijabetot i jasni znaci i simptomi na dijabeticna nefropatija (proteinurija, zgolemeno serumsko nivo na urea i kreatinin, poliurija, zgolemena aktivnost na NAG vo mockata. Tretman so prostaciklin (p.o. vo doza od 0.1 mg/kg /t.t./den, vo tekot na 4 nedeli, dovede do signifikantno namaluvanje na simptomite i znacite na bubreznite ostetuvanja, vo odnos na grupata zivotni koi ne primaa prostaciklin. Vrz osnova na dobienite rezultati moze da se zakluci deka prostaciklinot moze da ima znacajna uloga vo tretmanot na dijabeticnata nefropatija, eksperimentalno inducirana so streptozocin.

  9. Multi-saline sample distillation apparatus for hydrogen isotope analyses : design and accuracy

    Science.gov (United States)

    Hassan, Afifa Afifi

    1981-01-01

    A distillation apparatus for saline water samples was designed and tested. Six samples may be distilled simultaneously. The temperature was maintained at 400 C to ensure complete dehydration of the precipitating salts. Consequently, the error in the measured ratio of stable hydrogen isotopes resulting from incomplete dehydration of hydrated salts during distillation was eliminated. (USGS)

  10. Present status and strategic plan for the stable isotope reference materials at the IAEA.

    Science.gov (United States)

    Assonov, Sergey; Groening, Manfred

    2016-04-01

    The presentation will give the overview of the stable isotope reference materials (SI-RMs) under distribution by the IAEA, its stable isotope laboratory and capacities related to material testing & production as well as future plans. Historically, most of the IAEA reference materials were produced and made available via collaborations with expert stable isotope laboratories worldwide. The IAEA plans include several directions as follows: • Maintaining the scale-defining SI-RMs at the highest level and introducing adequate replacements when needed; • Monitoring existing SI-RMs for any potential alteration(s) and of isotopic values assigned; • Identifying and then addressing the needs for new SI-RMs, with the priority to address the most critical applications (environmental and climate related applications, human health, food safety studies) and newly emerging analytical isotope techniques; • Performing all measurements aimed for characterisation of new SI-RMs and the corresponding uncertainty evaluation in accordance to the latest metrological concepts; • Promoting metrological approaches on traceability and uncertainty evaluation in every day practice of stable isotope measurements; • Expanding the IAEA capacities for SI-RMs by (i) planning a renewed laboratory at IAEA; (ii) enlarging collaboration with expert laboratories aimed to help IAEA in production and characterisation of new SI-RMs. These major directions will help to address the increasing demand for Stable Isotope Reference Materials.

  11. National uses and needs for separated stable isotopes in physics, chemistry, and geoscience research

    Science.gov (United States)

    Zisman, M. S.

    Present uses of separated stable isotopes in the fields of physics, chemistry, and the geosciences were surveyed to identify current supply problems and to determine future needs. Demand for separated isotopes remains strong, with 220 different nuclides having been used in the past three years. The largest needs, in terms of both quantity and variety of isotopes, are found in nuclear physics research. Current problems include a lack of availability of many nuclides, unsatisfactory enrichment of rare species, and prohibitively high costs for certain important isotopes. Demand for separated isotopes is expected to remain roughly at present levels, although a shift toward more requests for highly enriched rare isotopes is predicted. Use of neutron rich nuclides below A = 100 for producing exotic ion beams at various accelerators and use of transition metal nuclei for nuclear magnetic resonance spectroscopy are expected to expand. An increase in the need for calibration standards for techniques of radiological dating, such as Sm/Nd and Lu/Hf is predicted, but in relatively small quantities. Most members of the research community would be willing to pay considerably more than they do now to maintain adequate supplies of stable isotopes.

  12. National uses and needs for separated stable isotopes in physics, chemistry, and geoscience research

    Energy Technology Data Exchange (ETDEWEB)

    Zisman, M.S.

    1982-01-01

    Present uses of separated stable isotopes in the fields of physics, chemistry, and the geosciences have been surveyed to identify current supply problems and to determine future needs. Demand for separated isotopes remains strong, with 220 different nuclides having been used in the past three years. The largest needs, in terms of both quantity and variety of isotopes, are found in nuclear physics research. Current problems include a lack of availability of many nuclides, unsatisfactory enrichment of rare species, and prohibitively high costs for certain important isotopes. It is expected that demands for separated isotopes will remain roughly at present levels, although there will be a shift toward more requests for highly enriched rare isotopes. Significantly greater use will be made of neutron-rich nuclides below A = 100 for producing exotic ion beams at various accelerators. Use of transition metal nuclei for nuclear magnetic resonance spectroscopy will expand. In addition, calibration standards will be required for the newer techniques of radiological dating, such as the Sm/Nd and Lu/Hf methods, but in relatively small quantities. Most members of the research community would be willing to pay considerably more than they do now to maintain adequate supplies of stable isotopes.

  13. Target-fueled nuclear reactor for medical isotope production

    Science.gov (United States)

    Coats, Richard L.; Parma, Edward J.

    2017-06-27

    A small, low-enriched, passively safe, low-power nuclear reactor comprises a core of target and fuel pins that can be processed to produce the medical isotope .sup.99Mo and other fission product isotopes. The fuel for the reactor and the targets for the .sup.99Mo production are the same. The fuel can be low enriched uranium oxide, enriched to less than 20% .sup.235U. The reactor power level can be 1 to 2 MW. The reactor is passively safe and maintains negative reactivity coefficients. The total radionuclide inventory in the reactor core is minimized since the fuel/target pins are removed and processed after 7 to 21 days.

  14. Calcium Isotope Analysis by Mass Spectrometry

    Science.gov (United States)

    Boulyga, S.; Richter, S.

    2010-12-01

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

  15. A serendipidade na medicina e na anestesiologia

    OpenAIRE

    Vale,Nilton Bezerra do; Delfino,José; Vale,Lúcio Flávio Bezerra do

    2005-01-01

    JUSTIFICATIVA E OBJETIVOS: Neste trabalho foram examinados mais de uma centena dos mais felizes acoplamentos de uma mente brilhante com a sorte benfazeja (serendipidade), através da releitura das mais relevantes histórias sobre invenções e descobertas relacionadas à ciência (n = 46), à Medicina (n = 46) e à Anestesiologia (n = 16). CONTEÚDO: Conceito de serendipidade; exemplos célebres de serendipidade em Ciência e Tecnologia; serendipidade na pesquisa e prática médicas; serendipidade na Anes...

  16. Applications of isotopes. [Need and cost of stable iotopes for use as tracers in biomedical and environmental studies

    Energy Technology Data Exchange (ETDEWEB)

    Kirby-Smith, J.S.

    1976-01-01

    Current and potential applications of stable isotopes as tracers in a number of biomedical and environmental areas are discussed. It is pointed out that a wide variety of problems exist in these fields whose solutions in principle are amenable to the isotopic approach. The number and diversity of these problems as well as the unique role stable isotopes can play in their solution illustrate the importance of achieving and maintaining a broad inventory of isotopic species. Experience has demonstrated unequivocally an additional overriding requirement for widespread exploration of stable isotopes by the scientific and technical community, i.e., the need for low cost availability of the materials in quantity. Some representative applications of /sup 12/C, /sup 13/C, /sup 14/N, /sup 15/N, /sup 16/O, /sup 17/O, and /sup 18/O are discussed.

  17. Influence of liquid structure on diffusive isotope separation in molten silicates and aqueous solutions

    Science.gov (United States)

    Watkins, James M.; DePaolo, Donald J.; Ryerson, Frederick J.; Peterson, Brook T.

    2011-06-01

    Molecular diffusion in natural volcanic liquids discriminates between isotopes of major ions (e.g., Fe, Mg, Ca, and Li). Although isotope separation by diffusion is expected on theoretical grounds, the dependence on mass is highly variable for different elements and in different media. Silicate liquid diffusion experiments using simple liquid compositions were carried out to further probe the compositional dependence of diffusive isotopic discrimination and its relationship to liquid structure. Two diffusion couples consisting of the mineral constituents anorthite (CaAl 2Si 2O 8; denoted AN), albite (NaAlSi 3O 8; denoted AB), and diopside (CaMgSi 2O 6; denoted DI) were held at 1450 °C for 2 h and then quenched to ambient pressure and temperature. Major-element as well as Ca and Mg isotope profiles were measured on the recovered quenched glasses. In both experiments, Ca diffuses rapidly with respect to Si. In the AB-AN experiment, D Ca/ D Si ≈ 20 and the efficiency of isotope separation for Ca is much greater than in natural liquid experiments where D Ca/ D Si ≈ 1. In the AB-DI experiment, D Ca/ D Si ≈ 6 and the efficiency of isotope separation is between that of the natural liquid experiments and the AB-AN experiment. In the AB-DI experiment, D Mg/ D Si ≈ 1 and the efficiency of isotope separation for Mg is smaller than it is for Ca yet similar to that observed for Mg in natural liquids. The results from the experiments reported here, in combination with results from natural volcanic liquids, show clearly that the efficiency of diffusive separation of Ca isotopes is systematically related to the solvent-normalized diffusivity - the ratio of the diffusivity of the cation ( D Ca) to the diffusivity of silicon ( D Si). The results on Ca isotopes are consistent with available data on Fe, Li, and Mg isotopes in silicate liquids, when considered in terms of the parameter D cation/ D Si. Cations diffusing in aqueous solutions display a similar relationship

  18. Isotopes a very short introduction

    CERN Document Server

    Ellam, Rob

    2016-01-01

    An isotope is a variant form of a chemical element, containing a different number of neutrons in its nucleus. Most elements exist as several isotopes. Many are stable while others are radioactive, and some may only exist fleetingly before decaying into other elements. In this Very Short Introduction, Rob Ellam explains how isotopes have proved enormously important across all the sciences and in archaeology. Radioactive isotopes may be familiar from their use in nuclear weapons, nuclear power, and in medicine, as well as in carbon dating. They have been central to establishing the age of the Earth and the origins of the solar system. Combining previous and new research, Ellam provides an overview of the nature of stable and radioactive isotopes, and considers their wide range of modern applications. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subjec...

  19. Exotic Structure of Carbon Isotopes

    CERN Document Server

    Suzuki, T; Hagino, K; Suzuki, Toshio; Sagawa, Hiroyuki; Hagino, Kouichi

    2002-01-01

    We studied firstly the ground state properties of C-isotopes using a deformed Hartree-Fock (HF)+ BCS model with Skyrme interactions. Shallow deformation minima are found in several neutron$-$rich C-isotopes. It is shown also that the deformation minima appear in both the oblate and the prolate sides in $^{17}$C and $^{19}$C having almost the same binding energies. Secondly, we carried out shell model calculations to study electromagnetic moments and electric dipole transitions of the C-isotopes. We point out the clear configuration dependence of the quadrupole and magnetic moments in the odd C-isotopes, which will be useful to find out the deformations and the spin-parities of the ground states of these nuclei. We studied electric dipole states of C-isotopes focusing on the interplay between low energy Pigmy strength and giant dipole resonances. Reasonable agreement is obtained with available experimental data for the photoreaction cross sections both in the low energy region below $\\hbar \\omega $=14 MeV and ...

  20. Bolonja na hrvatski način

    OpenAIRE

    Krstović, Jasna

    2009-01-01

    Iako je osnovna značajka obrazovnog sustava Republike Hrvatske horizontalna i okomita protočnost, ova se značajka još uvijek ne odnosi na obrazovanje odgajatelja. No u posljednje vrijeme događaju se pomaci i kvalitativne promjene koje su zahvatile i sustav obrazovanja hrvatskih odgajatelja.

  1. Short lived radioactive isotopes at TRI{mu}P facility

    Energy Technology Data Exchange (ETDEWEB)

    Shidling, P.D.; Giri, G.S.; Jungmann, K.; Kruithof, W.L.; Sohani, M.; Hoek, D.J. van der; Versolato, O.O.; Willmann, L.; Wilschut, H.W. [KVI, University of Groningen (Netherlands)

    2009-07-01

    At TRI{mu}P facility radioactive ion beam are produced and trapped for the study of fundamental symmetries and interaction in physics. The TRI{mu}P magnetic separator is used for in-flight production and separation of different radioactive isotopes. Different radioactive ion beam have been produced, via charge exchange, stripping, projectile fragmentation and fusion evaporation reactions in inverse kinematics. The radioactive beam can be used directly or can be converted to a low energy beam using a thermal ionizer. In this talk we focus on {sup 21}Na, {sup 213}Ra which are trapped as atoms or ions. With the trapping of {sup 21}Na we have completed the TRI{mu}P facility. Details on some selected aspect are discussed.

  2. Coordinated regulation of cardiac Na(+)/Ca (2+) exchanger and Na (+)-K (+)-ATPase by phospholemman (FXYD1).

    Science.gov (United States)

    Cheung, Joseph Y; Zhang, Xue-Qian; Song, Jianliang; Gao, Erhe; Chan, Tung O; Rabinowitz, Joseph E; Koch, Walter J; Feldman, Arthur M; Wang, JuFang

    2013-01-01

    Phospholemman (PLM) is the founding member of the FXYD family of regulators of ion transport. PLM is a 72-amino acid protein consisting of the signature PFXYD motif in the extracellular N terminus, a single transmembrane (TM) domain, and a C-terminal cytoplasmic tail containing three phosphorylation sites. In the heart, PLM co-localizes and co-immunoprecipitates with Na(+)-K(+)-ATPase, Na(+)/Ca(2+) exchanger, and L-type Ca(2+) channel. The TM domain of PLM interacts with TM9 of the α-subunit of Na(+)-K(+)-ATPase, while its cytoplasmic tail interacts with two small regions (spanning residues 248-252 and 300-304) of the proximal intracellular loop of Na(+)/Ca(2+) exchanger. Under stress, catecholamine stimulation phosphorylates PLM at serine(68), resulting in relief of inhibition of Na(+)-K(+)-ATPase by decreasing K(m) for Na(+) and increasing V(max), and simultaneous inhibition of Na(+)/Ca(2+) exchanger. Enhanced Na(+)-K(+)-ATPase activity lowers intracellular Na(+), thereby minimizing Ca(2+) overload and risks of arrhythmias. Inhibition of Na(+)/Ca(2+) exchanger reduces Ca(2+) efflux, thereby preserving contractility. Thus, the coordinated actions of PLM during stress serve to minimize arrhythmogenesis and maintain inotropy. In acute cardiac ischemia and chronic heart failure, either expression or phosphorylation of PLM or both are altered. PLM regulates important ion transporters in the heart and offers a tempting target for development of drugs to treat heart failure.

  3. Analysis and separation of boron isotopes; Analyse et separation des isotopes du bore

    Energy Technology Data Exchange (ETDEWEB)

    Perie, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-11-01

    The nuclear applications of boron-10 justify the study of a method of measurement of its isotopic abundance as well as of very small traces of boron in different materials. A systematic study of thermionic emission of BO{sub 2}Na{sub 2}{sup +} has been carried out. In the presence of a slight excess of alkalis, the thermionic emission is considerably reduced. On the other hand, the addition of a mixture of sodium hydroxide-glycerol (or mannitol) to borax permits to obtain an intense and stable beam. These results have permitted to establish an operative method for the analysis of traces of boron by isotopic dilution. In other respects, the needs of boron-10 in nuclear industry Justify the study of procedures of separation of isotopes of boron. A considerable isotopic effect has been exhibited in the chemical exchange reaction between methyl borate and borate salt in solution. In the case of exchange between methyl borate and sodium borate, the elementary separation factor {alpha} is: {alpha}=(({sup 11}B/{sup 10}B)vap.)/(({sup 11}B/{sup 10}B)liq.)=1.03{sub 3}. The high value of this elementary effect has been multiplied in a distillation column in which the problem of regeneration of the reactive has been resolved. An alternative procedure replacing the alkali borate by a borate of volatile base, for example diethylamine, has also been studied ({alpha}=1,02{sub 5} in medium hydro-methanolic with 2,2 per cent water). (author) [French] Les applications nucleaires du bore 10 justifient l'etude d'une methode de mesure de son abondance isotopique dans divers materiaux ainsi que le dosage de tres faibles traces de bore. Une etude systematique de l'emission thermoionique de BO{sub 2} Na{sub 2}{sup +} a ete effectuee. En presence d'un leger exces d'alcalins, l'emission thermoionique est considerablement reduite. Par contre l'addition au borax d'un melange soude-glycerol (ou mannitol) permet d'obtenir un faisceau stable et intense

  4. Photonuclear reactions on titanium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Belyshev, S. S. [Moscow State University (Russian Federation); Dzhilavyan, L. Z. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Ishkhanov, B. S.; Kapitonov, I. M. [Moscow State University (Russian Federation); Kuznetsov, A. A., E-mail: kuznets@depni.sinp.msu.ru; Orlin, V. N.; Stopani, K. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2015-03-15

    The photodisintegration of titanium isotopes in the giant-dipole-resonance energy region is studied by the photon-activation method. Bremsstrahlung photons whose spectrum has the endpoint energy of 55 MeV is used. The yields and integrated cross sections are determined for photoproton reactions on the titanium isotopes {sup 47,48,49,50}Ti. The respective experimental results are compared with their counterparts calculated on the basis of the TALYS code and a combined photonucleon-reaction model. The TALYS code disregards the isospin structure of the giant dipole resonance and is therefore unable to describe the yield of photoproton reactions on the heavy titanium isotopes {sup 49,50}Ti.

  5. A mechanism that maintains alternative life histories in a loggerhead sea turtle population.

    Science.gov (United States)

    Hatase, Hideo; Omuta, Kazuyoshi; Tsukamoto, Katsumi

    2013-11-01

    Intrapopulation variation in habitat use is commonly seen among mobile animals, yet the mechanisms maintaining it have rarely been researched among untrackable species. To investigate how alternative life histories are maintained in a population of the loggerhead sea turtle (Caretta caretta), cumulative reproductive output was evaluated and compared between small planktivores inhabiting oceanic areas (with water depths > 200 m) and large benthivores inhabiting neritic areas (depths life history parameters (clutch size, clutch frequency, breeding frequency, and remigration intervals), with the exception of emergence success. We did not find evidence of life history trade-offs, nor age-related changes in fecundity. Over the 26-year study period, we calculated a 2.4-fold greater reproductive output for neritic foragers than for oceanic ones, accounting for breeding and clutch frequency. Temporal consistencies in stable isotope ratios and remigration intervals within females suggested that female Japanese loggerheads show fidelity to respective foraging habitats throughout the adult stage. The large difference in productivity between the two groups was unlikely to be offset by the difference in survival during the period from aboveground emergence to first reproduction, suggesting that oceanic foragers have a lower level of fitness than neritic ones. Together with an absence of genetic structure between foraging groups, we infer that alternative life histories in a loggerhead turtle population are maintained by a conditional strategy.

  6. The terrestrial uranium isotope cycle.

    Science.gov (United States)

    Andersen, Morten B; Elliott, Tim; Freymuth, Heye; Sims, Kenneth W W; Niu, Yaoling; Kelley, Katherine A

    2015-01-15

    Changing conditions on the Earth's surface can have a remarkable influence on the composition of its overwhelmingly more massive interior. The global distribution of uranium is a notable example. In early Earth history, the continental crust was enriched in uranium. Yet after the initial rise in atmospheric oxygen, about 2.4 billion years ago, the aqueous mobility of oxidized uranium resulted in its significant transport to the oceans and, ultimately, by means of subduction, back to the mantle. Here we explore the isotopic characteristics of this global uranium cycle. We show that the subducted flux of uranium is isotopically distinct, with high (238)U/(235)U ratios, as a result of alteration processes at the bottom of an oxic ocean. We also find that mid-ocean-ridge basalts (MORBs) have (238)U/(235)U ratios higher than does the bulk Earth, confirming the widespread pollution of the upper mantle with this recycled uranium. Although many ocean island basalts (OIBs) are argued to contain a recycled component, their uranium isotopic compositions do not differ from those of the bulk Earth. Because subducted uranium was probably isotopically unfractionated before full oceanic oxidation, about 600 million years ago, this observation reflects the greater antiquity of OIB sources. Elemental and isotope systematics of uranium in OIBs are strikingly consistent with previous OIB lead model ages, indicating that these mantle reservoirs formed between 2.4 and 1.8 billion years ago. In contrast, the uranium isotopic composition of MORB requires the convective stirring of recycled uranium throughout the upper mantle within the past 600 million years.

  7. A Maintainability Prediction Method Considering Environmental Impacts and Cost

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Maintainability prediction is one kind of primary maintainability action. Design deficiency would be found through predicting maintainability parameters under certain conditions. Now a maintainability prediction method that mainly considers maintenance time or maintenance man-hour is a kind of prediction method with a single index. With increasing product complexity and people's environmental consciousness, more attention is paid to environment impacts and maintenance cost or resource consumption in the maintenance process. It is necessary for a maintainability prediction method that can predict maintenance cost and maintenance environmental impacts. A new maintainability prediction method is presented in this paper based on analyzing existing maintainability prediction methods.The method is MABTCE (maintenance activity based timing/costing/environment impact assessment )and can predict maintenance time, maintenance costing and maintenance environmental impacts andthen improve maintainability design with prediction results.

  8. Thermal Diversities of Two Na+/H+ Exchanges in Guinea Pig Red Cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To test the effect of hypothermia on Na+/H+ exchange, activated by shrinkage and cytoplasmic acidosis. Method Amiloride-sensitive Na+ influx in guinea pig red cells was traced with isotope 22Na and intracellular Na+ concentration was measured by emission flame photometry. Result Amiloride-sensitive Na+ influx decreased linearly as a function of temperatures (about 37℃) in shrunken cells, but increased in acidified cells. The up-regulation of acid-induced Na+/H+ exchange by elevated temperature was enhanced by hypo-osmolarity. Less sensitivity of intracellular H+ site at 41℃ may be the mechanism for the inhibition of shrinkage-induced Na+/H+ exchange by elevated temperature. Heating-mediated explosive increase in the activity of acid-induced Na+/H+ exchange may be due to enhanced extracellular Na+ sensitivity and lower intracellular pH caused by acidic metabolites. Acid-induced Na+/H+ ewxchange contributes to cytoplasmic Na+ accumulation. Conclusion These two modes of Na+/H+ exchange with different response to elevated temperature may play different roles in the cellular pathogenesis of heatstroke.

  9. Non-linear Isotope Effects

    DEFF Research Database (Denmark)

    Schmidt, Johan Albrecht

    The isotopic fractionation associated with photodissociation of N2O, OCS and CO2, at different altitudes in Earth’s atmosphere, is investigated theoretically using constructed quantum mechanical models of the dissociation processes (i.e. potential energy surfaces and relevant coupling elements...... or moderate, and overall sulfur fractionation in the stratosphere is very weak which does not exclude OCS from being an acceptable background the Stratospheric Sulfate Aerosol layer. (iii) CO2 photolysis in the upper stratosphere and lower mesosphere is highly fractionating in both isotopes, enriching...

  10. Use of the Bochum proton microprobe in isotope stratigraphy and paleoceanographic

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, F.; Bruckschen, P.; Korte, C. [Ruhr-University, Bochum (Germany). Institute fuer Geologie; Meijer, J. [Ruhr-Univ., Bochum (Germany). Inst. fuer Physik mit Ionenstrahlen; Veizer, J. [Ruhr-University Bochum (Germany). Institute fuer Geologie]|[Ottawa-Carleton Univ., Ottawa, ON (Canada)

    1998-06-01

    Over the past five years, the proton microprobe at Bochum (Germany) has been used as a trace element tool in the context of isotope stratigraphy and paleoceanographic studies. The Sr, O, and C isotopic composition of some biogenic material (e.g. calcitic brachiopod shells, phosphatic conodonts) is widely accepted to mirror, under favourable conditions, the isotopic composition of the coeval sea water. The latter, in turn, is a function of a variety of global processes, such as climatic change, volcanic activity, plate tectonics or circulation of ocean water. Thus, on the basis of the isotopic properties of fossil shell material, isotope curves can be constructed that reflect variations in the above factors over the entire Phanerozoic. However, as a consequence of the long time elapsed since deposition of the fossils, they are prone to chemical and isotopic alteration and may thus yield equivocal or even irrelevant information if no care is taken to monitor the degree of their diagenetic alteration. Trace element composition of the fossil material, combined with cathodoluminescence investigations, is one of the most frequently utilized tools to assess the diagenetic quality of the samples. Beam current was in the range of a few nA, resulting in charges of 1-10 {mu}C for a single measurement. Detection limits for point analyses were between 10 and 30 ppm for Mn, Fe, Sr, but considerably higher for rare earth elements. Accuracy around 10% for a number of elements analysed is reported. 8 refs., 2 figs.

  11. The separation of stable isotopes of carbon

    Science.gov (United States)

    Oziashvili, E. D.; Egiazarov, A. S.

    1989-04-01

    The present state of work on the separation of carbon isotopes by diffusion, fractional distillation, chemical isotopic exchange, and the selective excitation and dissociation of molecules in electrical discharges or in the field of laser radiation has been examined. The characteristics of new laboratory and industrial assemblies for separating carbon isotopes have been described. Promising directions of study aimed at developing effective technological processes for separating carbon isotopes have been noted. The bibliography contains 148 references.

  12. The lithium isotopic ratio in very metal-poor stars

    CERN Document Server

    Lind, Karin; Asplund, Martin; Collet, Remo; Magic, Zazralt

    2013-01-01

    Un-evolved, very metal-poor stars are the most important tracers of the cosmic abundance of lithium in the early universe. Combining the standard Big Bang nucleosynthesis model with Galactic production through cosmic ray spallation, these stars at [Fe/H]<-2 are expected to show an undetectably small 6Li/7Li isotopic signature. Evidence to the contrary may necessitate an additional pre-galactic production source or a revision of the standard model of Big Bang nucleosynthesis. We revisit the isotopic analysis of four halo stars, two with claimed 6Li-detections in the literature, to investigate the influence of improved model atmospheres and line formation treatment. For the first time, a combined 3D, NLTE (non-local thermodynamic equilibrium) modelling technique for Li, Na, and Ca lines is utilised to constrain the intrinsic line-broadening and to determine the Li isotopic ratio. We discuss the influence of 3D NLTE effects on line profile shapes and assess the realism of our modelling using the Ca excitation...

  13. Brief review on the development of isotope hydrology in China

    Institute of Scientific and Technical Information of China (English)

    汪集旸; 孙占学

    2001-01-01

    The development of isotope hydrology in China is briefly reviewed. It includes oxygen and hydrogen isotopes of precipitation, application of isotope hydrological methodologies in solving water resources problems, isotope hydrological studies on brines and salt lake waters, as well as isotope hydrological investigations of thermal waters. The review focuses on isotope hydrology in China during the last two decades.

  14. Dry phase reactor for generating medical isotopes

    Science.gov (United States)

    Mackie, Thomas Rockwell; Heltemes, Thad Alexander

    2016-05-03

    An apparatus for generating medical isotopes provides for the irradiation of dry-phase, granular uranium compounds which are then dissolved in a solvent for separation of the medical isotope from the irradiated compound. Once the medical isotope is removed, the dissolved compound may be reconstituted in dry granular form for repeated irradiation.

  15. Substitution of stable isotopes in Chlorella

    Science.gov (United States)

    Flaumenhaft, E.; Katz, J. J.; Uphaus, R. A.

    1969-01-01

    Replacement of biologically important isotopes in the alga Chlorella by corresponding heavier stable isotopes produces increasingly greater deviations from the normal cell size and changes the quality and distribution of certain cellular components. The usefulness of isotopically altered organisms increases interest in the study of such permuted organisms.

  16. Genesis of Sr Isotopes in Groundwater of Hebei Plain

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To analyze the genesis of Sr isotopes in groundwater of Hebei plain, time-accumulative effect of 87Sr/86Sr ratio was studied. It is shown that 87Sr/86Sr ratio increases with the increasing age and depth of groundwater and has a positive correlation to 4Heexc and a negative correlation to δ18O and δD.The groundwater is divided into three groups to discuss the relation between 87Sr/86Sr ratio and Sr2+ content: ① moderate Sr2+ content and higher 87Sr/86Sr ratio (water Ⅰ); ② lower Sr2+ content and higher 87Sr/86Sr ratio (water Ⅱ); and ③ higher Sr2+ content and lower 87Sr/86Sr ratio (water Ⅲ), that is hot water. On the basis of integrated analysis, it was considered that ① the radiogenic Sr in the Quaternary groundwater (Q4-Q1) originates from weathering of silicate rich in Na and Rb, mainly from plagioclase; ② the radiogenic Sr of hot water in Huanghua port is attributed to carbonate dissolution, with lower 87Sr/86Sr ratio and higher Sr/Na ratio; ③ the recharge area is laterally recharged by the groundwater flowing through igneous and metamorphic rocks, with moderate 87Sr/86Sr ratio. However, the formation mechanism of Sr isotopes in Tertiary groundwater needs further studies.

  17. Research on Maintainability Evaluation Model Based on Fuzzy Theory

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Maintainability influencing attributes are analyzed, their weight and value calculating methods are given, and the maintainability fuzzy evaluation method is proposed based on the relative closeness. According to the maintenance task simulation operated in virtual environment, the maintainability virtual evaluation model is built by analyzing the maintenance task for each replaceable unit of product.At last, a case study is given based upon the main landing gear system of a certain type civil aircraft, and the result indicates that the model is suitable for maintainability qualitative evaluation and can support maintainability concurrent design.

  18. Isotope Harvesting Opportunities at FRIB

    Science.gov (United States)

    Morrissey, David

    2017-01-01

    The fragmentation of fast heavy ion beams now at the National Superconducting Cyclotron Laboratory (NSCL) and in the future at the Facility for Rare Isotope Beams (FRIB) under construction produce an unprecedentedly broad spectrum of radionuclides but only a small fraction are used in the on-line rare-isotope program. Projectile fragmentation facilities provide an electromagnetically purified beam of a single projectile fragment for nuclear physics experiments ranging from low energy astrophysics, through nuclear structure studies, to probing fundamental symmetries. By augmenting the NSCL and FRIB production facilities with complimentary collection and purification of discarded ions, called isotope harvesting with chemical purification, many other nuclides will become available for off-line experiments in parallel with the primary experiment. A growing user community has established a list of key target isotopes and is working with the FRIB design team to allow inclusion of necessary equipment in the future. An overview of the possibilities and the techniques will be presented in this talk. Supported by Office of Science, US DOE and Michigan State University.

  19. Operation of Electromagnetic Isotope Separator

    Institute of Scientific and Technical Information of China (English)

    MI; Ya-jing

    2015-01-01

    In 2015,we mainly completed the installation of the electromagnetic isotope separator comprehensive technical transformation projects,including the work of installation,debugging,commissioning and acceptance.In June 30,2015,according to the schedule requirements,the project

  20. Research Progress of Isotope Technology

    Institute of Scientific and Technical Information of China (English)

    Department; of; Isotope

    2015-01-01

    Radioactive isotope is one of the origins of nonnuclear power technology.In the 12th Five Year Plan period,CIAE made breakthrough progresses on several important fields such as research and development of preparation of radioactive nuclides,preparation of radioactive source and study of radiopharmaceuticals relied on different financial support,successfully

  1. Bayesian stable isotope mixing models

    Science.gov (United States)

    In this paper we review recent advances in Stable Isotope Mixing Models (SIMMs) and place them into an over-arching Bayesian statistical framework which allows for several useful extensions. SIMMs are used to quantify the proportional contributions of various sources to a mixtur...

  2. Calcium isotope analysis by mass spectrometry.

    Science.gov (United States)

    Boulyga, Sergei F

    2010-01-01

    The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. The present article discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. In Sections 2 and 3, mass spectrometric methods applied to precise stable isotope analysis and to the determination of (41)Ca are described. Section 4 contains a short summary of selected applications, and includes tracer experiments and the potential use

  3. 20 Ne(p, γ)22Na and 22Ne(p, γ)23Na Reaction Study with 5U-4 St. Ana Accelerator

    Science.gov (United States)

    Lyons, Stephanie; Goerres, Joachim; Jung, Hyo Soon; Robertson, Dan; Setoodehnia, Kiana; Stech, Ed; Wiescher, Michael; Kontos, Antonios

    2014-09-01

    Hydrogen burning can proceed via the NeNa cycle in stars whose stellar temperature is greater than 0.05GK. The NeNa cycle is important for the nucleosynthesis of Ne, Na, and Mg isotopes. Direct capture and the high energy tail of a subthreshold resonance dominate the stellar reaction rate for 20Ne(p, γ)21Na. The strength of the non-resonant contributions were measured relative to the resonance at 1.17 MeV. Due to conflicting results, we have remeasured the strength of this resonance relative to the 1.28 MeV resonance in 22Ne(p, γ)23Na using implanted neon targets. Study of this reaction has continued using the newly commissioned 5U-4 St. Ana Accelerator and re-furbished Rhinoceros Gas Target.

  4. At NA2

    CERN Multimedia

    1977-01-01

    One of the NA2 calorimeter sections is moved in. The NA2 calorimeter was divided in two halves, to the left and the right of the beam, each half consisting of sheets of passive high Z material interleaved with blades of plastic scintillators. The photo shows on the right, the upstream 'electron' module with eleven lead plates for a total radiation length of 20.

  5. A global Ge isotope budget

    Science.gov (United States)

    Baronas, J. Jotautas; Hammond, Douglas E.; McManus, James; Wheat, C. Geoffrey; Siebert, Christopher

    2017-04-01

    We present measurements of Ge isotope composition and ancillary data for samples of river water, low- and high-temperature hydrothermal fluids, and seawater. The dissolved δ74Ge composition of analyzed rivers ranges from 2.0 to 5.6‰, which is significantly heavier than previously determined values for silicate rocks (δ74Ge = 0.4-0.7‰, Escoube et al., Geostand. Geoanal. Res., 36(2), 2012) from which dissolved Ge is primarily derived. An observed negative correlation between riverine Ge/Si and δ74Ge signatures suggests that the primary δ74Ge fractionation mechanism during rock weathering is the preferential incorporation of light isotopes into secondary weathering products. High temperature (>150 °C) hydrothermal fluids analyzed in this study have δ74Ge of 0.7-1.6‰, most likely fractionated during fluid equilibration with quartz in the reaction zone. Low temperature (25-63 °C) hydrothermal fluids are heavier (δ74Ge between 2.9‰ and 4.1‰) and most likely fractionated during Ge precipitation with hydrothermal clays. Seawater from the open ocean has a δ74Gesw value of 3.2 ± 0.4‰, and is indistinguishable among the different ocean basins at the current level of precision. This value should be regulated over time by the isotopic balance of Ge sources and sinks, and a new compilation of these fluxes is presented, along with their estimated isotopic compositions. Assuming steady-state, non-opal Ge sequestration during sediment authigenesis likely involves isotopic fractionation Δ74Gesolid-solution that is -0.6 ± 1.8‰.

  6. Antinociceptive effects of high-dose remifentanil in male methadone-maintained patients.

    Science.gov (United States)

    Hay, Justin L; White, Jason M; Bochner, Felix; Somogyi, Andrew A

    2008-10-01

    The treatment of acute pain in patients maintained on methadone is difficult due to increased pain sensitivity (hyperalgesia) and cross-tolerance to other opioids. This study aimed to investigate whether remifentanil elicits antinociception in methadone-maintained subjects in a dose-dependent manner. Eight chronic methadone-maintained subjects attended the testing session approximately 20 h after their normal methadone dose (range 50-110 mgday(-1)). Following a 20 min saline infusion, subjects were administered intravenous remifentanil in seven increasing doses ranging from 0.5 to 3.5 microgkg(-1)min(-1), each for 2 0min. Testing was performed in the last 10 min of each infusion. The testing measures included nociception, as measured by the cold pressor test, withdrawal using the subjective opiate withdrawal scale (SOWS), and subjective opioid effects using the morphine-benzedrine group scale (MBG). Results showed dose-dependent increase in cold pressor tolerance time from baseline of 15.6+/-3.5 (mean+/-SEM)s up to 77.3+/-24.7s during this dosing protocol. During the infusion typical mu-opioid receptor agonist side effects were observed, but with no withdrawal. Methadone-maintained patients demonstrate significant tolerance to remifentanil and may require opioid doses 20-30 higher than required for the treatment of acute pain in opioid-naïve patients.

  7. Modelling stable water isotopes: Status and perspectives

    Directory of Open Access Journals (Sweden)

    Werner M.

    2010-12-01

    Full Text Available Modelling of stable water isotopes H2 18O and HDO within various parts of the Earth’s hydrological cycle has clearly improved our understanding of the interplay between climatic variations and related isotope fractionation processes. In this article key principles and major research results of stable water isotope modelling studies are described. Emphasis is put on research work using explicit isotope diagnostics within general circulation models as this highly complex model setup bears many resemblances with studies using simpler isotope modelling approaches.

  8. Cosmogenic radionuclide production in NaI(Tl) crystals

    CERN Document Server

    Amaré, J; Cuesta, C; García, E; Ginestra, C; Martínez, M; Oliván, M A; Ortigoza, Y; de Solórzano, A Ortiz; Pobes, C; Puimedón, J; Sarsa, M L; Villar, J A; Villar, P

    2014-01-01

    The production of long-lived radioactive isotopes in materials due to the exposure to cosmic rays on Earth surface can be an hazard for experiments demanding ultra-low background conditions, typically performed deep underground. Production rates of cosmogenic isotopes in all the materials present in the experimental set-up, as well as the corresponding cosmic rays exposure history, must be both well known in order to assess the relevance of this effect in the achievable sensitivity of a given experiment. Although NaI(Tl) scintillators are being used in experiments aiming at the direct detection of dark matter since the first nineties of the last century, very few data about cosmogenic isotopes production rates have been published up to date. In this work we present data from two 12.5 kg NaI(Tl) detectors, developed in the frame of the ANAIS project, which were installed inside a convenient shielding at the Canfranc Underground Laboratory just after finishing surface exposure to cosmic rays. The very fast star...

  9. Zinc isotopic compositions of breast cancer tissue.

    Science.gov (United States)

    Larner, Fiona; Woodley, Laura N; Shousha, Sami; Moyes, Ashley; Humphreys-Williams, Emma; Strekopytov, Stanislav; Halliday, Alex N; Rehkämper, Mark; Coombes, R Charles

    2015-01-01

    An early diagnostic biomarker for breast cancer is essential to improve outcome. High precision isotopic analysis, originating in Earth sciences, can detect very small shifts in metal pathways. For the first time, the natural intrinsic Zn isotopic compositions of various tissues in breast cancer patients and controls were determined. Breast cancer tumours were found to have a significantly lighter Zn isotopic composition than the blood, serum and healthy breast tissue in both groups. The Zn isotopic lightness in tumours suggests that sulphur rich metallothionein dominates the isotopic selectivity of a breast tissue cell, rather than Zn-specific proteins. This reveals a possible mechanism of Zn delivery to Zn-sequestering vesicles by metallothionein, and is supported by a similar signature observed in the copper isotopic compositions of one breast cancer patient. This change in intrinsic isotopic compositions due to cancer has the potential to provide a novel early biomarker for breast cancer.

  10. Heavy atom isotope effects on enzymatic reactions

    Science.gov (United States)

    Paneth, Piotr

    1994-05-01

    The theory of isotope effects, which has proved to be extremely useful in providing geometrical details of transition states in a variety of chemical reactions, has recently found an application in studies of enzyme-catalyzed reactions. These reactions are multistep in nature with few steps being partially rate-limiting, thus interpretation of these isotope effects is more complex. The theoretical framework of heavy-atom isotope effects on enzymatic reactions is critically analyzed on the basis of recent results of: carbon kinetic isotope effects on carbonic anhydrase and catalytic antibodies; multiple carbon, deuterium isotope effects on reactions catalyzed by formate decarboxylase; oxygen isotope effects on binding processes in reactions catalyzed by pyruvate kinase; and equilibrium oxygen isotope effect on binding an inhibitor to lactate dehydrogenase. The advantages and disadvantages of reaction complexity in learning details of formal and molecular mechanisms are discussed in the examples of reactions catalyzed by phosphoenolpyruvate carboxylase, orotidine decarboxylase and glutamine synthetase.

  11. Measuring SNM Isotopic Distributions using FRAM

    Energy Technology Data Exchange (ETDEWEB)

    Geist, William H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-02

    The first group of slides provides background information on the isotopic composition of plutonium. It is shown that 240Pu is the critical isotope in neutron coincidence/multiplicity counting. Next, response function analysis to determine isotopic composition is discussed. The isotopic composition can be determined by measuring the net peak counts from each isotope and then taking the ratio of the counts for each isotope relative to the total counts for the element. Then FRAM (Fixed energy Response function Analysis with Multiple efficiencies) is explained. FRAM can control data acquisition, automatically analyze newly acquired data, analyze previously acquired data, provide information on the quality of the analysis, and facilitate analysis in unusual situations (non-standard energy calibrations, gamma rays from non-SNM isotopes, poor spectra (within limits)).

  12. ETAŽNA LASTNINA S POUDARKOM NA ZVEtL

    OpenAIRE

    Cvetko, Tadej

    2014-01-01

    Etažna lastnina je lastnina posameznega dela zgradbe in solastnina na skupnih delih, ki služijo vsem ali nekaterim posameznim delom zgradbe. Etažna lastnino na območju Republike Slovenije je uvedel Zakon o lastnini na delih stavbe kot odgovor na potrebo po hitri nacionalizaciji stanovanj in odrazu doslednega uvajanja osnovne ideje takratnega socialističnega duha t.j. družbene lastnine. Slovenija kot mlada demokratična država je ob tranziciji iz socialističnega v demokratični sistem poskušala ...

  13. Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems

    Energy Technology Data Exchange (ETDEWEB)

    Nimz, G. J., LLNL

    1998-06-01

    A variety of physical processes affect solute concentrations within catchment waters. The isotopic compositions of the solutes can indicate which processes have determined the observed concentrations. These processes together constitute the physical history of the water. Many solutes in natural waters are derived from the interaction between the water and the rock and/or soil within the system - these are termed `lithogenic` solutes. The isotopic compositions of these solutes provide information regarding rock-water interactions. Many other solutes have their isotopic compositions determined both within and outside of the catchment - i.e., in addition to being derived from catchment rock and soil, they are solutes that are also transported into the catchment. Important members of this group include solutes that have isotopic compositions produced by atomic particle interactions with other nuclides. The source of the atomic particles can be cosmic radiation (producing `cosmogenic` nuclides in the atmosphere and land surface), anthropogenic nuclear reactions (producing `thermonuclear` nuclides), or radioactive and fission decay of naturally-occurring elements, principally {sup 238}U (producing `in-situ` lithogenic nuclides in the deep subsurface). Current language usage often combines all of the atomic particle-produced nuclides under the heading `cosmogenic nuclides`, and for simplicity we will often follow that usage here, although always indicating which variety is being discussed. This paper addresses the processes that affect the lithogenic and cosmogenic solute concentrations in catchment waters, and how the isotopic compositions of the solutes can be used in integrative ways to identify these processes, thereby revealing the physical history of the water within a catchment system. The concept of a `system` is important in catchment hydrology. A catchment is the smallest landscape unit that can both participate in all of the aspects of the hydrologic cycle and

  14. The Na+ transport in gram-positive bacteria defect in the Mrp antiporter complex measured with 23Na nuclear magnetic resonance.

    Science.gov (United States)

    Górecki, Kamil; Hägerhäll, Cecilia; Drakenberg, Torbjörn

    2014-01-15

    (23)Na nuclear magnetic resonance (NMR) has previously been used to monitor Na(+) translocation across membranes in gram-negative bacteria and in various other organelles and liposomes using a membrane-impermeable shift reagent to resolve the signals resulting from internal and external Na(+). In this work, the (23)Na NMR method was adapted for measurements of internal Na(+) concentration in the gram-positive bacterium Bacillus subtilis, with the aim of assessing the Na(+) translocation activity of the Mrp (multiple resistance and pH) antiporter complex, a member of the cation proton antiporter-3 (CPA-3) family. The sodium-sensitive growth phenotype observed in a B. subtilis strain with the gene encoding MrpA deleted could indeed be correlated to the inability of this strain to maintain a lower internal Na(+) concentration than an external one.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  16. Neutron spectra and dosimetric features of isotopic neutron sources: a review

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Martinez O, S. A., E-mail: fermineutron@yahoo.com [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte 39-115, 150003 Tunja, Boyaca (Colombia)

    2015-10-15

    A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of {sup 24}NaBe, {sup 24}NaD{sub 2}O, {sup 116}InBe, {sup 140}LaBe, {sup 238}PuLi, {sup 239}PuBe, {sup 241}AmB, {sup 241}AmBe, {sup 241}AmF, {sup 241}AmLi, {sup 242}CmBe, {sup 210}PoBe, {sup 226}RaBe, {sup 252}Cf and {sup 252}Cf/D{sub 2}O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

  17. An absorbent for an application to a package for a liquid radioactive isotope for medical usage

    Energy Technology Data Exchange (ETDEWEB)

    Bang, K.S.; Lim, S.P.; Lee, J.C.; Seo, K.S.; Han, H.S. [Korea Atomic Energy Research Inst., Daejeon (Korea)

    2004-07-01

    A radioactive isotope has to be safely transport from the producing center to the consuming center. The shipping package to safely transport the radioactive isotope should be able to withstand the prescribed conditions by law. In the field of nuclear medicine, the radioactive isotope is used in a liquid or capsule form. A Type A package, which is to transport liquid radioactive materials, shall be provided with a containment system composed of primary inner and secondary outer containment components or shall be provided with sufficient absorbent material to absorb twice the volume of the liquid contents. Hospitals prefer to use not only convenient but also re-usable packages. To apply an absorbent material to the Type A package, that is to transport liquid radioactive isotope, the free absorbency of the absorbents was estimated. In the case of a liquid with NaOH 0.4%, the free absorbency of the melanine form was the most superior at 91 g/g. In the case of a liquid with Na 0.9%, the free absorbency of the melanine form was the most excellent at 88 g/g also.

  18. The Cl Isotope Composition of the Moon as evidence for an Anhydrous Mantle (Invited)

    Science.gov (United States)

    Sharp, Z. D.; Shearer, C., Jr.; McKeegan, K. D.; Barnes, J.; Wang, Y.

    2010-12-01

    The chlorine isotope composition of primitive terrestrial basalts and carbonaceous chondrites cover a narrow range centered around 0‰ with a total variation of ± 0.5‰. In contrast, the chlorine isotope composition of bulk samples and in situ ion microprobe analyses of lunar basalts and glasses cover a range of 25‰. Three possibilities were considered to explain the large spread: 1) initial isotopic heterogeneities, 2) devolatilization from solar wind/micrometeorite bombardment, 3) degassing under anhydrous conditions. The first of these possibilities is rejected because the Moon went through an magma ocean stage which would have homogenized any isotopic heterogeneities. To examine surface effects, we chose samples that have extremely different degrees of surface exposure. We find no correlation between the Cl isotope composition and surface exposure. We also conducted a laboratory experiment in which a thin film of NaCl was bombarded with a proton source for 24 hours with no change in Cl isotope composition. The third possibility is that the fractionation is explained by the anhydrous character of the Moon. On Earth, the volatiling Cl species is HCl. HCl is known to preferentially incorporate 37Cl relative to 35Cl due to the high bond strength of the molecule. This is offset by the higher translational velocity of H35Cl, so that overall, there is very little Cl isotope fractionation during degassing. We propose that lunar basalts were anhydrous and the volatile Cl species were metal chlorides, such as ZnCl2, NaCl, FeCl2, etc. The bond strength of metal chlorides and Cl dissolved in a basalt are similar, so that fractionation is caused mainly by volatilization, with the light isotopologue preferentially lost to the vapor phase. This idea is supported by the consistent lower Cl isotope ratios of water soluble salt fraction (~10 ‰ lower) and the lowest lunar Cl isotope values close to those of bulk Earth. The H content of lunar magmas must have been lower

  19. Differential Proteomic Analysis of Anthers between Cytoplasmic Male Sterile and Maintainer Lines in Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Zhiming Wu

    2013-11-01

    Full Text Available Cytoplasmic male sterility (CMS, widely used in the production of hybrid seeds, is a maternally inherited trait resulting in a failure to produce functional pollen. In order to identify some specific proteins associated with CMS in pepper, two-dimensional gel electrophoresis (2-DE was applied to proteomic analysis of anthers/buds between a CMS line (designated NA3 and its maintainer (designated NB3 in Capsicum annuum L. Thirty-three spots showed more than 1.5-fold in either CMS or its maintainer. Based on mass spectrometry, 27 spots representing 23 distinct proteins in these 33 spots were identified. Proteins down-regulated in CMS anthers/buds includes ATP synthase D chain, formate dehydrogenase, alpha-mannosidas, RuBisCO large subunit-binding protein subunit beta, chloroplast manganese stabilizing protein-II, glutathione S-transferase, adenosine kinase isoform 1T-like protein, putative DNA repair protein RAD23-4, putative caffeoyl-CoA 3-O-methyltransferase, glutamine synthetase (GS, annexin Cap32, glutelin, allene oxide cyclase, etc. In CMS anthers/buds, polyphenol oxidase, ATP synthase subunit beta, and actin are up-regulated. It was predicted that male sterility in NA3 might be related to energy metabolism turbulence, excessive ethylene synthesis, and suffocation of starch synthesis. The present study lays a foundation for future investigations of gene functions associated with pollen development and cytoplasmic male sterility, and explores the molecular mechanism of CMS in pepper.

  20. Natural fractionation of uranium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Noordmann, Janine

    2015-01-24

    The topic of this thesis was the investigation of U (n({sup 238}U) / n({sup 235}U)) isotope variations in nature with a focus on samples (1) that represent the continental crust and its weathering products (i.e. granites, shales and river water) (2) that represent products of hydrothermal alteration on mid-ocean ridges (i.e. altered basalts, carbonate veins and hydrothermal water) and (3) from restricted euxinic basins (i.e. from the water column and respective sediments). The overall goal was to explore the environmental conditions and unravel the mechanisms that fractionate the two most abundant U isotopes, n({sup 238}U) and n({sup 235}U), on Earth.

  1. Lasers utilizing CO2 isotopes

    Science.gov (United States)

    Pechenin, Iu. V.; Domanov, M. S.

    1980-08-01

    The emission spectra and power characteristics of CW (C-12)(O-16)2, (C-13)(O-16)2, (C-12)(O-16)(O-18)2 and (C-12)(O-18) lasers are investigated. Laser output power is found to depend equally on the proportion of carbon and oxygen isotopes in the active medium for all isotopes except the asymmetrical (C-12)(O-16)(O-18), in which maximum output power is four to five times less due to the doubling of emission lines and limited enrichment caused by recombination into (C-12)(O-16)2 and (C-12)(O-18)2 molecules during discharge. The unsaturated gain is observed to increase linearly with enrichment, with that of nonsymmetrical molecules half that of the symmetrical molecules, while the maximum power output is independent of enrichment.

  2. Interstellar Isotopes: Prospects with ALMA

    Science.gov (United States)

    Charnley Steven B.

    2010-01-01

    Cold molecular clouds are natural environments for the enrichment of interstellar molecules in the heavy isotopes of H, C, N and O. Anomalously fractionated isotopic material is found in many primitive Solar System objects, such as meteorites and comets, that may trace interstellar matter that was incorporated into the Solar Nebula without undergoing significant processing. Models of the fractionation chemistry of H, C, N and O in dense molecular clouds, particularly in cores where substantial freeze-out of molecules on to dust has occurred, make several predictions that can be tested in the near future by molecular line observations. The range of fractionation ratios expected in different interstellar molecules will be discussed and the capabilities of ALMA for testing these models (e.g. in observing doubly-substituted isotopologues) will be outlined.

  3. Copper isotope signatures in modern marine sediments

    Science.gov (United States)

    Little, Susan H.; Vance, Derek; McManus, James; Severmann, Silke; Lyons, Timothy W.

    2017-09-01

    The development of metal stable isotopes as tools in paleoceanography requires a thorough understanding of their modern marine cycling. To date, no Cu isotope data has been published for modern sediments deposited under low oxygen conditions. We present data encompassing a broad spectrum of hydrographic and redox regimes, including continental margin and euxinic (sulphide-containing) settings. Taken together with previously published data from oxic settings, these data indicate that the modern oceanic sink for Cu has a surprisingly homogeneous isotopic composition of about +0.3‰ (δ65Cu, relative to NIST SRM976). We suggest that this signature reflects one of two specific water-column processes: (1) an equilibrium isotope fractionation between soluble, isotopically heavy, Cu complexed to strong organic ligands and an isotopically light pool sorbed to particles that deliver Cu to the sediment, or (2) an equilibrium isotope fractionation between the same isotopically heavy ligand-bound pool and the particle reactive free Cu2+ species, with the latter being scavenged by particulates and thereby delivered to the sediment. An output flux of about +0.3‰ into sediments is isotopically light relative to the known inputs to the ocean (at around +0.6‰) and the seawater value of +0.6 to +0.9‰, suggesting the presence of an as yet unidentified isotopically light source of Cu to the oceans. We hypothesize that this source may be hydrothermal, or may result from the partial dissolution of continentally derived particles.

  4. Comparative isotope ecology of African great apes.

    Science.gov (United States)

    Oelze, Vicky M; Fahy, Geraldine; Hohmann, Gottfried; Robbins, Martha M; Leinert, Vera; Lee, Kevin; Eshuis, Henk; Seiler, Nicole; Wessling, Erin G; Head, Josephine; Boesch, Christophe; Kühl, Hjalmar S

    2016-12-01

    The isotope ecology of great apes is a useful reference for palaeodietary reconstructions in fossil hominins. As extant apes live in C3-dominated habitats, variation in isotope signatures is assumed to be low compared to hominoids exploiting C4-plant resources. However, isotopic differences between sites and between and within individuals are poorly understood due to the lack of vegetation baseline data. In this comparative study, we included all species of free-ranging African great apes (Pan troglodytes, Pan paniscus, Gorilla sp.). First, we explore differences in isotope baselines across different habitats and whether isotopic signatures in apes can be related to feeding niches (faunivory and folivory). Secondly, we illustrate how stable isotopic variations within African ape populations compare to other extant and extinct primates and discuss possible implications for dietary flexibility. Using 701 carbon and nitrogen isotope data points resulting from 148 sectioned hair samples and an additional collection of 189 fruit samples, we compare six different great ape sites. We investigate the relationship between vegetation baselines and climatic variables, and subsequently correct great ape isotope data to a standardized plant baseline from the respective sites. We obtained temporal isotopic profiles of individual animals by sectioning hair along its growth trajectory. Isotopic signatures of great apes differed between sites, mainly as vegetation isotope baselines were correlated with site-specific climatic conditions. We show that controlling for plant isotopic characteristics at a given site is essential for faunal data interpretation. While accounting for plant baseline effects, we found distinct isotopic profiles for each great ape population. Based on evidence from habituated groups and sympatric great ape species, these differences could possibly be related to faunivory and folivory. Dietary flexibility in apes varied, but temporal variation was overall

  5. Effect of a High-Fructose Weight-Maintaining Diet on Lipogenesis and Liver Fat.

    Science.gov (United States)

    Schwarz, Jean-Marc; Noworolski, Susan M; Wen, Michael J; Dyachenko, Artem; Prior, Jessica L; Weinberg, Melissa E; Herraiz, Laurie A; Tai, Viva W; Bergeron, Nathalie; Bersot, Thomas P; Rao, Madhu N; Schambelan, Morris; Mulligan, Kathleen

    2015-06-01

    Consumption of high-fructose diets promotes hepatic fatty acid synthesis (de novo lipogenesis [DNL]) and an atherogenic lipid profile. It is unclear whether these effects occur independent of positive energy balance and weight gain. We compared the effects of a high-fructose, (25% of energy content) weight-maintaining diet to those of an isocaloric diet with the same macronutrient distribution but in which complex carbohydrate (CCHO) was substituted for fructose. Eight healthy men were studied as inpatients for consecutive 9-day periods. Stable isotope tracers were used to measure fractional hepatic DNL and endogenous glucose production (EGP) and its suppression during a euglycemic-hyperinsulinemic clamp. Liver fat was measured by magnetic resonance spectroscopy. Weight remained stable. Regardless of the order in which the diets were fed, the high-fructose diet was associated with both higher DNL (average, 18.6 ± 1.4% vs 11.0 ± 1.4% for CCHO; P = .001) and higher liver fat (median, +137% of CCHO; P = .016) in all participants. Fasting EGP and insulin-mediated glucose disposal did not differ significantly, but EGP during hyperinsulinemia was greater (0.60 ± 0.07 vs 0.46 ± 0.06 mg/kg/min; P = .013) with the high-fructose diet, suggesting blunted suppression of EGP. Short-term high-fructose intake was associated with increased DNL and liver fat in healthy men fed weight-maintaining diets.

  6. Constraints on the vital effect in coccolithophore and dinoflagellate calcite by oxygen isotopic modification of seawater

    Science.gov (United States)

    Hermoso, Michaël; Horner, Tristan J.; Minoletti, Fabrice; Rickaby, Rosalind E. M.

    2014-09-01

    In this study, we show that there are independent controls of 18O/16O and 13C/12C fractionation in coccolithophore and dinoflagellate calcite due to the contrasting kinetics of each isotope system. We demonstrate that the direction and magnitude of the oxygen isotope fractionation with respect to equilibrium is related to the balance between calcification rate and the replenishment of the internal pool of dissolved inorganic carbon (DIC). As such, in fast growing cells, such as those of Emiliania huxleyi and Gephyrocapsa oceanica (forming the so-called “heavy group”), calcification of the internal carbon pool occurs faster than complete isotopic re-adjustment of the internal DIC pool with H2O molecules. Hence, coccoliths reflect the heavy oxygen isotope signature of the CO2 overprinting the whole DIC pool. Conversely, in large and slow growing cells, such as Coccolithus pelagicus ssp. braarudii, complete re-equilibration is achieved due to limited influx of CO2 leading to coccoliths that are precipitated in conditions close to isotopic equilibrium (“equilibrium group”). Species exhibiting the most negative oxygen isotope composition, such as Calcidiscus leptoporus (“light group”), precipitate coccolith under increased pH in the coccolith vesicle, as previously documented by the “carbonate ion effect”. We suggest that, for the carbon isotope system, any observed deviation from isotopic equilibrium is only “apparent”, as the carbon isotopic composition in coccolith calcite is controlled by a Rayleigh fractionation originating from preferential incorporation of 12C into organic matter. Therefore, species with low PIC/POC ratios as E. huxleyi and G. oceanica are shifted towards positive carbon isotope values as a result of predominant carbon fixation into the organic matter. By contrast, cells with higher PIC/POC as C. braarudii and C. leptoporus maintain, to some extent, the original negative isotopic composition of the CO2. The calcareous

  7. NAKUPOVANJE NA SPLETU

    OpenAIRE

    Visenjak, Monika

    2013-01-01

    Nakupovanje na spletu je prihodnost poslovanja. Za podjetja pomeni manjše stroške, lažje prilagajanje tržnim pogojem. Hitreje lahko razvijajo odnose in analizirajo uporabnike, saj jim je dan dostop o nakupnih podatkih uporabnika. Za potrošnike je nakupovanje na spletu možnost hitrega, preprostega in učinkovitega nakupovanja od doma ali pisarne. Pomembno je, da se seznanijo z vsemi informacijami in pogoji spletnih trgovin, saj se lahko le tako izognejo nezadovoljstvu ob nakupu v spletni trgovi...

  8. Preparation of the saphenous vein for coronary artery bypass grafting: a new technique "no touch" that maintains the vein wall integral and provides high immediate patency Preparo da veia safena na cirurgia de revascularização miocárdica: uma nova técnica -"no touch"- que mantém a parede da veia íntegra e proporciona uma alta perviabilidade imediata

    Directory of Open Access Journals (Sweden)

    Domingos S. R. Souza

    2003-12-01

    patency rate. Furthermore, the mechanical properties provided by the cushion of surrounding tissue in graft harvested by NT technique may contribute to the observed high patency rate.OBJETIVO: O objetivo deste trabalho é apresentar uma nova técnica "no touch" de preparo da veia safena e sua importância clínica. Esta nova técnica consiste na retirada da veia safena do seu leito, juntamente com um pedículo de tecido adiposo, protegendo a veia contra espasmos e, conseqüentemente, da necessidade de distendê-la durante a operação. MÉTODO: O estudo foi realizado em dois tempos: 1 Inicialmente, foi realizado um estudo prospectivo e randomizado, envolvendo 156 pacientes que foram submetidos à operação de revascularização miocárdica. Neste estudo nós comparamos a técnica "no touch" (NT com duas outras: a convencional (C e a intermediária (I. Foi feita uma avaliação detalhada da morfologia endotelial, utilizando a microscopia eletrônica, enquanto que a perviabilidade das pontes foi determinada com um exame angiográfico executado num período médio de 18 meses após a operação. 2 Finalmente, a enzima óxido nítrico síntase (NOS foi identificada com ajuda do estudo imunohistoquímico e também pela localização auto-radiográfica de (3H-L- Nitro-Arginina (NOARG. RESULTADOS: A avaliação morfológica mostrou integridade endotelial de 97% nas veias que foram tratadas pela técnica NT; enquanto quase metade da superfície endotelial das veias tratadas pelas outras duas técnicas exibiu ausência de células endoteliais. O exame angiográfico revelou perviabilidade de 95,4% para as pontes do grupo NT, 88,9% para as pontes do grupo (C e 86,2% para as pontes do grupo (I. O estudo imunohistoquímico revelou a presença de NOS nas três camadas que compõem a parede da veia quando, as mesmas, foram tratadas pela técnica NT. Por outro lado, foi observada uma elevada redução desta enzima nas veias que foram tratadas pela técnica (C. A análise auto

  9. Polarization maintaining large-mode area photonic crystal fibre

    DEFF Research Database (Denmark)

    Folkenberg, Jacob Riis; Nielsen, Martin Dybendal; Mortensen, N.A.

    2004-01-01

    We report on a polarization maintaining large mode area photonic crystal fiber. Unlike, previous work on polarization maintaining photonic crystal fibers, birefringence is introduced using stress applying parts. This has allowed us to realize fibers, which are both single mode at any wavelength a...

  10. 19 CFR 163.2 - Persons required to maintain records.

    Science.gov (United States)

    2010-04-01

    ... brokers. Each customs broker must also make and maintain records and make such records available in... 19 Customs Duties 2 2010-04-01 2010-04-01 false Persons required to maintain records. 163.2 Section 163.2 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND...

  11. Surveying the factors that influence maintainability: research design

    NARCIS (Netherlands)

    Hordijk, W.T.B.; Wieringa, Roelf J.

    2005-01-01

    We want to explore and analyse design decisions that influence maintainability of software. Software maintainability is important because the effort expended on changes and fixes in software is a major cost driver. We take an empirical, qualitative approach, by investigating cases where a change has

  12. Coherent Beam Combination of Two Polarization Maintaining Ytterbium Fibre Amplifiers

    Institute of Scientific and Technical Information of China (English)

    HOU Jing; XIAO Rui; JIANG Zong-Fu; CHENG Xiang-Ai; SHU Bai-Hong; CHEN Jin-Bao; LIU Ze-Jin

    2005-01-01

    @@ We investigate coherent beam combination of fibre laser beams by phase locking. Phase noise of a polarization maintaining ytterbium fibre amplifier is inspected with a fibre interferometer. In a feed back control loop, two fibre polarization maintaining ytterbium amplifiers are phase locked and coherent combined when the phase noise is properly controlled by a LiNO3 phase modulator.

  13. 34 CFR 668.163 - Maintaining and accounting for funds.

    Science.gov (United States)

    2010-07-01

    ...) Accounting and internal control systems and financial records. (1) An institution must maintain accounting... financial records in accordance with the provisions under § 668.24. (e) Standard of conduct. An institution... 34 Education 3 2010-07-01 2010-07-01 false Maintaining and accounting for funds. 668.163...

  14. A novel methodology to investigate isotopic biosignatures

    Science.gov (United States)

    Horner, T. J.; Lee, R. B. Y.; Henderson, G. M.; Rickaby, R. E. M.

    2012-04-01

    An enduring goal of trace metal isotopic studies of Earth History is to find isotopic 'fingerprints' of life or of life's individual physiochemical processes. Generally, such signatures are sought by relating an isotopic effect observed in controlled laboratory conditions or a well-characterized environment to a more complex system or the geological record. However, such an approach is ultimately limited because life exerts numerous isotopic fractionations on any one element so it is hard to dissect the resultant net fractionation into its individual components. Further, different organisms, often with the same apparent cellular function, can express different isotopic fractionation factors. We have used a novel method to investigate the isotopic fractionation associated with a single physiological process-enzyme specific isotopic fractionation. We selected Cd isotopes since only one biological use of Cd is known, CdCA (a Cd/Zn carbonic anhydrase from the coastal diatom T. Weissflogii). Thus, our investigation can also inform the long standing mystery as to why this generally toxic element appears to have a nutrient-like dissolved isotopic and concentration profile in the oceans. We used the pET-15b plasmid to insert the CdCA gene into the E. coli genome. There is no known biochemical function for Cd in E. coli, making it an ideal vector for studying distinct physiological processes within a single organism. The uptake of Cd and associated isotopic fractionation was determined for both normal cells and those expressing CdCA. It was found that whole cells always exhibited a preference for the light isotopes of Cd, regardless of the expression of CdCA; adsorption of Cd to cell surfaces was not seen to cause isotopic fractionation. However, the cleaning procedure employed exerted a strong control on the observed isotopic composition of cells. Using existing protein purification techniques, we measured the Cd isotopic composition of different subcellular fractions of E

  15. Multivariate analysis of calcareous nanno fossils and stable isotopic ({delta}{sup 18}O and {delta}{sup 13}C) in the upper Campanian - lower Maastrichtian of the Campos Basin, Brazil; Analise multivariada em nanofosseis calcarios e isotopos estaveis ({delta}{sup 18}O e {delta}{sup 13}C) do Campaniano superior - Maastrichtiano inferior na Bacia de Campos

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luiz Carlos Veiga de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Gerencia de Bioestratigrafia e Paleoecologia]. E-mail: lcveiga@petrobras.com.br; Rodrigues, Rene; Lemos, Valesca Brasil

    2005-05-01

    Qualitative analysis in calcareous nanno fossils is a powerful tool for bio stratigraphic uses, principally in identification of bio zones and determination of relative age. But quantitative studies must be applied for pale oceanographic applications and high resolution bio stratigraphy. In order to better understand the relationships between the different species of nanno fossils, new methodologies and non-traditional correlation tools were tested on a 18 m upper Campanian - lower Maastrichtian core from Campos Basin. Multiple regression helped to determine the best counting method. Watznaueria barnesae and Micula decussata dominate the fossil assemblage and have inverse abundances to each other. Both were opportunist species in competition for nutrients. Q mode factorial analysis (57 samples, 19 variables) was applied to the same core and shows that two factors explain 99.2% of the total variance of the micro fossil assemblage. The first factor represents 83.6% and the second factor only 15.6% of the total variance. The former is associated with Watznaueria barnesae, Cribrosphaerella ehrenbergii and Stradneria crenulata, which represent the original population of nano plankton. The latter factor is associated with Micula decussata, which is believed to represent the effect of solution at the sediment water interface. Both factors were used to develop a dissolution-sea level curve for nanno fossils. When combined with oxygen and carbon isotopes, this curve clearly shows that higher dissolution occurred during the late Campanian - early Maastrichtian time when {delta}{sup 18}O, {delta}{sup 13} C and TOC all had lower values. These correlations indicate a strong link between high sea levels, high temperatures and lower amount of continental organic debris. (author)

  16. Pb isotopes during mingling and melting

    DEFF Research Database (Denmark)

    Waight, Tod Earle; Lesher, Charles E.

    2010-01-01

    Pb isotopic data are presented for hybrid rocks formed by mingling between mantle-derived tholeiitic magma of the Eocene Miki Fjord macrodike (East Greenland) and melt derived from the adjacent Precambrian basement. Bulk mixing and AFC processes between end-members readily identified in the field...... fail to model the Pb isotope systematics. Selective contamination during diffusional exchange, which can explain the complex Sr and Nd isotope compositions of the hybrid rocks (Blichert-Toft et al., 1992), cannot fully account for the variability of the Pb isotopic data using the identified crustal end......-members. The crustal anatectic end-member, although similar in Sr and Nd isotope composition, has a markedly different Pb isotopic composition than its source gneiss. The differences are consistent with preferential incorporation of radiogenic Pb from accessory phases such as metamict zircon or loosely-bound Pb from...

  17. Measuring In Vivo Ureagenesis With Stable Isotopes

    Science.gov (United States)

    Yudkoff, Marc; Mew, Nicholas Ah; Daikhin, Yevgeny; Horyn, Oksana; Nissim, Ilana; Nissim, Itzhak; Payan, Irma; Tuchman, Mendel

    2010-01-01

    Stable isotopes have been an invaluable adjunct to biomedical research for more than 70 years. Indeed, the isotopic approach has revolutionized our understanding of metabolism, revealing it to be an intensely dynamic process characterized by an unending cycle of synthesis and degradation. Isotopic studies have taught us that the urea cycle is intrinsic to such dynamism, since it affords a capacious mechanism by which to eliminate waste nitrogen when rates of protein degradation (or dietary protein intake) are especially high. Isotopes have enabled an appreciation of the degree to which ureagenesis is compromised in patients with urea cycle defects. Indeed, isotopic studies of urea cycle flux correlate well with the severity of cognitive impairment in these patients. Finally, the use of isotopes affords an ideal tool with which to gauge the efficacy of therapeutic interventions to augment residual flux through the cycle. PMID:20338795

  18. Isotope Geochemistry for Comparative Planetology of Exoplanets

    Science.gov (United States)

    Mandt, K. E.; Atreya, S.; Luspay-Kuti, A.; Mousis, O.; Simon, A.; Hofstadter, M. D.

    2017-01-01

    Isotope geochemistry has played a critical role in understanding processes at work in and the history of solar system bodies. Application of these techniques to exoplanets would be revolutionary and would allow comparative planetology with the formation and evolution of exoplanet systems. The roadmap for comparative planetology of the origins and workings of exoplanets involves isotopic geochemistry efforts in three areas: (1) technology development to expand observations of the isotopic composition of solar system bodies and expand observations to isotopic composition of exoplanet atmospheres; (2) theoretical modeling of how isotopes fractionate and the role they play in evolution of exoplanetary systems, atmospheres, surfaces and interiors; and (3) laboratory studies to constrain isotopic fractionation due to processes at work throughout the solar system.

  19. Stable Oxygen-18 and Deuterium Isotopes

    DEFF Research Database (Denmark)

    Müller, Sascha

    The application of stable Oxygen-18 (18O) and Deuterium (2H) isotopes, as a tracer for fluxes between different compartments of the water cycle was subject of the present PhD-thesis. During a three year period, temporal data from a wide range of water cycle constituents was collected from...... the Skjern River catchment, Denmark. The presented applications focused on studying the isotopic 'input signal' to the hydrosphere in the form of precipitation, the isotopic 'output signal' with its related dynamic processes at a coastal saltwater-freshwater interface (groundwater isotopes) and the temporal...... development within a given lowland headwater catchment (stream water isotopes). Based on our investigations on the precipitation isotopic composition a local meteoric water line (LMWL) was constructed and expressed as: δ2H=7.4 δ18O + 5.36‰. Moreover, we showed that under maritime temperature climate influence...

  20. Chronic and selective inhibition of basolateral membrane Na-K-ATPase uniquely regulates brush border membrane Na absorption in intestinal epithelial cells

    Science.gov (United States)

    Manoharan, Palanikumar; Gayam, Swapna; Arthur, Subha; Palaniappan, Balasubramanian; Singh, Soudamani; Dick, Gregory M.

    2015-01-01

    Na-K-ATPase, an integral membrane protein in mammalian cells, is responsible for maintaining the favorable intracellular Na gradient necessary to promote Na-coupled solute cotransport processes [e.g., Na-glucose cotransport (SGLT1)]. Inhibition of brush border membrane (BBM) SGLT1 is, at least in part, due to the diminished Na-K-ATPase in villus cells from chronically inflamed rabbit intestine. The aim of the present study was to determine the effect of Na-K-ATPase inhibition on the two major BBM Na absorptive pathways, specifically Na-glucose cotransport and Na/H exchange (NHE), in intestinal epithelial (IEC-18) cells. Na-K-ATPase was inhibited using 1 mM ouabain or siRNA for Na-K-ATPase-α1 in IEC-18 cells. SGLT1 activity was determined as 3-O-methyl-d-[3H]glucose uptake. Na-K-ATPase activity was measured as the amount of inorganic phosphate released. Treatment with ouabain resulted in SGLT1 inhibition at 1 h but stimulation at 24 h. To further characterize this unexpected stimulation of SGLT1, siRNA silencing was utilized to inhibit Na-K-ATPase-α1. SGLT1 activity was significantly upregulated by Na-K-ATPase silencing, while NHE3 activity remained unaltered. Kinetics showed that the mechanism of stimulation of SGLT1 activity was secondary to an increase in affinity of the cotransporter for glucose without a change in the number of cotransporters. Molecular studies demonstrated that the mechanism of stimulation was not secondary to altered BBM SGLT1 protein levels. Chronic and direct silencing of basolateral Na-K-ATPase uniquely regulates BBM Na absorptive pathways in intestinal epithelial cells. Specifically, while BBM NHE3 is unaffected, SGLT1 is stimulated secondary to enhanced affinity of the cotransporter. PMID:25652450

  1. Riso na epilepsia

    Directory of Open Access Journals (Sweden)

    Edymar Jardim

    1967-06-01

    Full Text Available São estudados três casos de síndrome convulsiva temporal, com manifestações concomitantes de riso na sua fase inicial. As características principais foram a imotivação e á incoercibilidade do riso. Esses sintomas desapareceram com o uso de anticonvulsivantes.

  2. The NA48 experiment

    CERN Multimedia

    1995-01-01

    The NA48 experiment is designed to study the Charge-Parity (CP) violation. CP violation is observed in certain very rare decays. Its study is important in understanding Nature's preference of matter over antimatter, which resulted in asymmetry soon after the Big Bang, creating a matter-dominated Universe.

  3. Biotecnologia na agricultura

    Directory of Open Access Journals (Sweden)

    Helaine Carrer

    2010-01-01

    Full Text Available A expectativa de o crescimento populacional atingir 9 bilhões de habitantes em 2050 em adição às questões da sustentabilidade e do aquecimento global nos desafiam a aumentar a oferta de alimentos. Uma metodologia alternativa que contribua para a redução do impacto desse cenário envolve a biotecnologia, que, nas últimas décadas, trouxe marcantes oportunidades tecnológicas na agricultura, resultando em relevante desenvolvimento na obtenção de novas variedades de plantas, na melhoria da qualidade de diversos alimentos e atualmente também na bioenergia. As técnicas biotecnológicas envolvendo os marcadores moleculares, a genômica e a transformação genética estão transformando a agricultura e são discutidas neste artigo.The expected population growth to reach 9 billion by 2050 in addition to issues of sustainability and global warming challenges us to increase the supply of food. An alternative approach to help reducing the impact of this scenario involves biotechnology which in recent decades has brought remarkable technological opportunities in the agriculture that resulted in relevant development in obtaining new plant varieties, improved quality of different foods, and now also in bioenergy. The biotechnology techniques involving molecular markers, genomics and genetic transformation are transforming agriculture and will be discussed in this article.

  4. Salinity controls on Na incorporation in Red Sea planktonic foraminifera

    Science.gov (United States)

    Mezger, E. M.; Nooijer, L. J.; Boer, W.; Brummer, G. J. A.; Reichart, G. J.

    2016-12-01

    Whereas several well-established proxies are available for reconstructing past temperatures, salinity remains challenging to assess. Reconstructions based on the combination of (in)organic temperature proxies and foraminiferal stable oxygen isotopes result in relatively large uncertainties, which may be reduced by application of a direct salinity proxy. Cultured benthic and planktonic foraminifera showed that Na incorporation in foraminiferal shell calcite provides a potential independent proxy for salinity. Here we present the first field calibration of such a potential proxy. Living planktonic foraminiferal specimens from the Red Sea surface waters were collected and analyzed for their Na/Ca content using laser ablation quadrupole inductively coupled plasma mass spectrometry. Using the Red Sea as a natural laboratory, the calibration covers a broad range of salinities over a steep gradient within the same water mass. For both Globigerinoides ruber and Globigerinoides sacculifer calcite Na/Ca increases with salinity, albeit with a relatively large intraspecimen and interspecimen variability. The field-based calibration is similar for both species from a salinity of 36.8 up to 39.6, while values for G. sacculifer deviate from this trend in the northernmost transect. It is hypothesized that the foraminifera in the northernmost part of the Red Sea are (partly) expatriated and hence should be excluded from the Na/Ca-salinity calibration. Incorporation of Na in foraminiferal calcite therefore provides a potential proxy for salinity, although species-specific calibrations are still required and more research on the effect of temperature is needed.

  5. Normalization of oxygen and hydrogen isotope data

    Science.gov (United States)

    Coplen, T.B.

    1988-01-01

    To resolve confusion due to expression of isotopic data from different laboratories on non-corresponding scales, oxygen isotope analyses of all substances can be expressed relative to VSMOW or VPDB (Vienna Peedee belemnite) on scales normalized such that the ??18O of SLAP is -55.5% relative to VSMOW. H3+ contribution in hydrogen isotope ratio analysis can be easily determined using two gaseous reference samples that differ greatly in deuterium content. ?? 1988.

  6. Production of radioactive isotopes from stable isotopes, for nuclear medicine; A partir d`isotopes stables, production d`isotopes radioactifs pour la medecine nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Bourdoiseau, M. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Office des Rayonnements Ionisants

    1994-12-31

    Around 15 radioactive isotopes only are used for nuclear medicine diagnosis (kinetics or preferential fixation in the body); characteristics of these {gamma} and {beta}-minus emitters are presented: period, energy, production mode (isotopic filiation, fission product separation, cyclotron, reactor); details are given on applications, production mode, properties and consumption of various isotopes: Technetium 99m, Thallium 201, Iodine 123, Indium 111, Gallium 67, Rhenium 186, Erbium 169, Yttrium 90, Iron 59, Chromium 51, Krypton 81m. 1 tab.

  7. Silicon isotopes: from cosmos to benthos

    OpenAIRE

    Chakrabarti, Ramananda

    2015-01-01

    Silicon is the second most abundant element on the Earth and one of the more abundant elements in our Solar System. Variations in the relative abundance of the stable isotopes of Si (Si isotope fractionation) in different natural reservoirs, both terrestrial (surface and deep Earth) as well as extra-terrestrial (e.g. meteorites, lunar samples), are a powerful tracer of present and past processes involving abiotic as well as biotic systems. The versatility of the Si isotope tracer is reflected...

  8. Quantitative microbial ecology through stable isotope probing.

    Science.gov (United States)

    Hungate, Bruce A; Mau, Rebecca L; Schwartz, Egbert; Caporaso, J Gregory; Dijkstra, Paul; van Gestel, Natasja; Koch, Benjamin J; Liu, Cindy M; McHugh, Theresa A; Marks, Jane C; Morrissey, Ember M; Price, Lance B

    2015-11-01

    Bacteria grow and transform elements at different rates, and as yet, quantifying this variation in the environment is difficult. Determining isotope enrichment with fine taxonomic resolution after exposure to isotope tracers could help, but there are few suitable techniques. We propose a modification to stable isotope probing (SIP) that enables the isotopic composition of DNA from individual bacterial taxa after exposure to isotope tracers to be determined. In our modification, after isopycnic centrifugation, DNA is collected in multiple density fractions, and each fraction is sequenced separately. Taxon-specific density curves are produced for labeled and nonlabeled treatments, from which the shift in density for each individual taxon in response to isotope labeling is calculated. Expressing each taxon's density shift relative to that taxon's density measured without isotope enrichment accounts for the influence of nucleic acid composition on density and isolates the influence of isotope tracer assimilation. The shift in density translates quantitatively to isotopic enrichment. Because this revision to SIP allows quantitative measurements of isotope enrichment, we propose to call it quantitative stable isotope probing (qSIP). We demonstrated qSIP using soil incubations, in which soil bacteria exhibited strong taxonomic variations in (18)O and (13)C composition after exposure to [(18)O]water or [(13)C]glucose. The addition of glucose increased the assimilation of (18)O into DNA from [(18)O]water. However, the increase in (18)O assimilation was greater than expected based on utilization of glucose-derived carbon alone, because the addition of glucose indirectly stimulated bacteria to utilize other substrates for growth. This example illustrates the benefit of a quantitative approach to stable isotope probing.

  9. NaCl处理对盐地碱蓬开花及Na+、K+含量的影响%Effects of NaCl Treatments on Flower Number, Na+and K+Contents of Suaeda salsa

    Institute of Scientific and Technical Information of China (English)

    郭建荣; 王宝山

    2014-01-01

    To investigate the role of salinity in lfowering of euhalophyte Suaeda salsa, lfower number of differ-ent branches and per plant, Na+, K+content and Na+/K+ratio of leaves, stems and lfowers of S. salsa were deter-mined under conditions of 1 (control), 200 and 400 mmol·L-1 NaCl treatment. Compared with the control, 200 mmol·L-1NaCl treatment signiifcantly increased the lfower number of branches and individual plant of S. salsa, the lfower number per plant increased by 69.90%, Na+content, Na+/K+ratio in the lfowers increased by 1.41 and 1.77 times respectively, Na+content, Na+/K+ratio in the leaves of the ifrst branches increased by 3.96 and 4.96 times respectively, and Na+content, Na+/K+ratio in the stems increased by 7.00 and 12.39 times respectively. Flower number per plant increased by 19.00%under 400 mmol·L-1 NaCl treatment, Na+content and Na+/K+ra-tio in lfowers increased by 2.09 and 3.21 times respectively, Na+content, Na+/K+ratio in the leaves of the ifrst branches increased by 4.28 and 6.50 times respectively, and Na+content, Na+/K+ratio in the stems increased by 7.65 and 15.40 times respectively. These results suggested that certain concentration of external NaCl promotes lfowering of euhalophytes S. salsa possibly via compartmentalization of Na+into leaves and stems and mobili-zation of K+in the leaves and stems into the lfowers to maintain a proper Na+/K+ratio in the lfowers.%为探讨盐地碱蓬(Suaeda salsa)开花与盐的关系,研究了1(对照)、200和400 mmol·L-1 NaCl处理对盐地碱蓬不同分枝和单株开花数目、叶片和茎及花器官中的Na+、K+含量及Na+/K+比的影响。结果表明:与对照相比,200 mmol·L-1 NaCl处理下盐地碱蓬分枝及单株开花数目增加最显著,单株开花数目增加了69.90%,花器官中的Na+含量、Na+/K+比分别增加了1.41倍和1.77倍,而一级叶片的Na+含量、Na+/K+比分别增加了3.96倍和4.96倍,茎中Na+含量、Na+/K+比分别增加了7.00倍和12.39倍。400 mmol

  10. Laboratory and Field Measurements of the Nitrogen Isotopic Composition of NOx

    Science.gov (United States)

    Fibiger, D. L.; Miller, D. J.; Dahal, B. R.; Lew, A. F.; Peltier, R.; Hastings, M. G.

    2014-12-01

    The nitrogen isotopic composition of nitrogen oxides (NOx = NO + NO2) has been measured from several NOx emissions sources in prior studies. These measurements have utilized a variety of methods for collecting the NOx as nitrate or nitrite for isotopic analysis, but none of these methods have been verified for complete conversion of NOx. Less than 100% conversion can result in isotopic fractionations. We present a method for accurately measuring the nitrogen isotopic composition of NOx using a .25 M KMnO4 and 0.5 M NaOH solution. Based on laboratory tests, this technique has been found to collect all NOx passed through under a variety of conditions (e.g., air flow rate, NOx concentration, temperature, humidity), allowing for diagnosis of δ15N-NOx without correction for fractionation. The precision across the entire analytic technique is 1.5‰. This active collection method is advantageous for collecting NOx over short time scales in environments with highly variable NOx sources and concentrations. The major drawback of the NaOH/KMnO4 method is a significant nitrate background found in the KMnO4, but this background is consistent and can be easily accounted for. We aim to use this method to provide more robust constraints on the isotopic signatures of NOx emissions from different sources. Initial results will be presented from lab- and field-based collections of NOx emissions. Emissions from a diesel engine were measured in a laboratory smog chamber and yielded δ15N values with a mean of -18.0‰ (n = 5, 1σ = 0.97‰). Measurements of δ15N-NOx were also made on a rooftop between two highways in Providence, RI. The values ranged from -7.7 to -0.63‰ for different time periods sampled, with excellent reproducibility in side-by-side collections. Additionally, the NaOH/KMnO4 was deployed in a laboratory study of biomass burning (FLAME4) to analyze the nitrogen isotopic composition of NOx produced from the burning of variety of materials (e.g. trees, agricultural

  11. Scattering lengths of calcium and barium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dammalapati, U.; Willmann, L.; Knoop, S. [Kernfysisch Versneller Instituut (KVI), University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); LaserLaB Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)

    2011-11-15

    We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba) in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca does not provide other isotopes alternative to the recently Bose condensed {sup 40}Ca that suffers strong losses because of a very large scattering length. For Ba we show by using a model potential that the even isotopes cover a broad range of scattering lengths, opening the possibility of BEC for at least one of the isotopes.

  12. The trend of stable isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Yonekawa, Shigeru [Power Reactor and Nuclear Fuel Development Corp., Kamisaibara, Okayama (Japan). Ningyo Toge Works; Aoki, Eiji; Yato, Yumio

    1994-12-01

    Recently, stable isotopes are used in the field of medical science, nuclear physics, environmental science and agriculture. This report reviews the present status of stable isotope enrichment in ORNL, Urenco, Russia and PNC. Further the utilization method of the stable isotopes in the field of medical science, nuclear power and material science are described, and the application possibility of Laser separation method and Gas Centrifuge method are estimated. There are many overseas actual results of stable isotope separation with Gas Centrifuge method, therefore this method is possible enough in principle. (author).

  13. Copper isotope fractionation by desert shrubs

    Energy Technology Data Exchange (ETDEWEB)

    Navarrete, Jesica U., E-mail: jnavarrete2@miners.utep.edu [University of Texas at El Paso, Department of Geological Sciences, 500 W. University Ave, El Paso, TX 79968 (United States); Viveros, Marian; Ellzey, Joanne T. [University of Texas at El Paso, Department of Biological Sciences, El Paso, TX 79968 (United States); Borrok, David M. [University of Texas at El Paso, Department of Geological Sciences, 500 W. University Ave, El Paso, TX 79968 (United States)

    2011-06-15

    Copper has two naturally occurring stable isotopes of masses 63 and 65 which can undergo mass dependent fractionation during various biotic and abiotic chemical reactions. These interactions and their resulting Cu isotope fractionations can be used to determine the mechanisms involved in the cycling of Cu in natural systems. In this study, Cu isotope changes were investigated at the organismal level in the metal-accumulating desert plant, Prosopis pubescens. Initial results suggest that the lighter Cu isotope was preferentially incorporated into the leaves of the plant, which may suggest that Cu was actively transported via intracellular proteins. The roots and stems show a smaller degree of Cu isotope fractionation and the direction and magnitude of the fractionations was dependent upon the levels of Cu exposure. Based on this and previous work with bacteria and yeast, a trend is emerging that suggests the lighter Cu isotope is preferentially incorporated into biological components, while the heavier Cu isotope tends to become enriched in aqueous solutions. In bacteria, plants and animals, intracellular Cu concentrations are strictly regulated via dozens of enzymes that can bind, transport, and store Cu. Many of these enzymes reduce Cu(II) to Cu(I). These initial results seem to fit into a broader picture of Cu isotope cycling in natural systems where oxidation/reduction reactions are fundamental in controlling the distributions of Cu isotopes.

  14. Comparing Effective Treatments for Attention-Maintained and Escape- Maintained Behaviors in Children with Behavior Disorders: Brief Review and Analysis

    OpenAIRE

    Lauren Worcester; T. F. McLaughlin

    2013-01-01

    This literature review compares treatment for attention-maintainedversus escape maintained aberrant behavior in children with behavior disorders. Specifically, studies utilizing time out procedures, differential reinforcement procedures, noncontingent reinforcement, and functional communication training are discussed. It was found that these are effective treatments for attention-maintained behaviors; while escape extinction, positive and negative reinforcement, functional communication trai...

  15. Ultrafiltration by a compacted clay membrane. I - Oxygen and hydrogen isotopic fractionation. II - Sodium ion exclusion at various ionic strengths.

    Science.gov (United States)

    Coplen, T. B.; Hanshaw, B. B.

    1973-01-01

    Laboratory experiments were carried out to determine the magnitude of the isotopic fractionation of distilled water and of 0.01N NaCl forced to flow at ambient temperature under a hydraulic pressure drop of 100 bars across a montmorillonite disk compacted to a porosity of 35% by a pressure of 330 bars. The ultrafiltrates in both experiments were depleted in D by 2.5% and in O-18 by 0.8% relative to the residual solution. No additional isotopic fractionation due to a salt-filtering mechanism was observed at NaCl concentrations up to 0.01N. Adsorption is most likely the principal mechanism which produces isotopic fractionation, but molecular diffusion may play a minor role. The results suggest that oxygen and hydrogen isotopic fractionation of ground water during passage through compacted clayey sediments should be a common occurrence, in accord with published interpretations of isotopic data from the Illinois and Alberta basins. It is shown how it is possible to proceed from the ion exchange capacity of clay minerals and, by means of the Donnan membrane equilibrium concept and the Teorell-Meyer-Siever theory, develop a theory to explain why and to what extent ultrafiltration occurs when solutions of known concentration are forced to flow through a clay membrane.

  16. Hydrogen Isotopes Record the History of the Martian Hydrosphere and Atmosphere

    Science.gov (United States)

    Usui, T.; Simon, J. I.; Jones, J. H.; Kurokawa, H.; Sato, M.; Alexander, C. M. O'D; Wang, J.

    2015-01-01

    The surface geology and geomorphology of Mars indicates that it was once warm enough to maintain a large body of liquid water on its surface, though such a warm environment might have been transient. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. This study presents insights from hydrogen isotopes for the origin and evolution of Martian water reservoirs.

  17. Absence of fractionation of mercury isotopes during trophic transfer of methylmercury to freshwater fish in captivity

    Science.gov (United States)

    Kwon, Sae Yun; Blum, Joel D.; Carvan, Michael J.; Basu, Niladri; Head, Jessica A.; Madenjian, Charles P.; David, Solomon R.

    2012-01-01

    We performed two controlled experiments to determine the amount of mass-dependent and mass-independent fractionation (MDF and MIF) of methylmercury (MeHg) during trophic transfer into fish. In experiment 1, juvenile yellow perch (Perca flavescens) were raised in captivity on commercial food pellets and then their diet was either maintained on unamended food pellets (0.1 μg/g MeHg) or was switched to food pellets with 1.0 μg/g or 4.0 μg/g of added MeHg, for a period of 2 months. The difference in δ202Hg (MDF) and Δ199Hg (MIF) between fish tissues and food pellets with added MeHg was within the analytical uncertainty (δ202Hg, 0.07 ‰; Δ199Hg, 0.06 ‰), indicating no isotope fractionation. In experiment 2, lake trout (Salvelinus namaycush) were raised in captivity on food pellets and then shifted to a diet of bloater (Coregonus hoyi) for 6 months. The δ202Hg and Δ199Hg of the lake trout equaled the isotopic composition of the bloater after 6 months, reflecting reequilibration of the Hg isotopic composition of the fish to new food sources and a lack of isotope fractionation during trophic transfer. We suggest that the stable Hg isotope ratios in fish can be used to trace environmental sources of Hg in aquatic ecosystems.

  18. Use of porous space maintainers in staged mandibular reconstruction.

    Science.gov (United States)

    Henslee, Allan M; Spicer, Patrick P; Shah, Sarita R; Tatara, Alexander M; Kasper, F Kurtis; Mikos, Antonios G; Wong, Mark E

    2014-05-01

    The success of mandibular reconstructions depends not only on restoring the form and function of lost bone but also on the preservation of the overlying soft tissue layer. In this case study, 5 porous polymethylmethacrylate space maintainers fabricated via patient-specific molds were implanted initially to maintain the vitality of the overlying oral mucosa during staged mandibular reconstructions. Three of the 5 patients healed well; the other 2 patients developed dehiscences, likely due to a thin layer of soft tissue overlying the implant. The results presented provide evidence that a larger investigation of space maintainers fabricated using this method is warranted.

  19. Mg Isotope Evolution During Water-Rock Interaction in a Carbonate Aquifer

    Science.gov (United States)

    Zhang, Z.; Jacobson, A. D.; Lundstrom, C. C.; Huang, F.

    2008-12-01

    To better understand how Mg isotopes behave during weathering and aqueous transport, we used a Nu Plasma MC-ICP-MS to measure δ26Mg values (relative to DSM-3) in water samples along a 236 km flow path in the Madison aquifer of South Dakota, a confined carbonate aquifer recharging in the igneous Black Hills. We also analyzed local granite and dolomite samples to characterize the Mg isotope composition of source rocks constituting the recharge zone and aquifer, respectively. Repeated analyses of Mg standard solutions yielded external precisions (2σ) better than 0.1 permil for δ26Mg(CAM-1, - 2.584±0.071, n=13; UIMg-1, -2.217±0.087, n=9.). The Madison aquifer provides a unique opportunity to quantify Mg isotope effects during water-rock interaction because (1) fluids and rock have chemically equilibrated over a much longer timescale (up to ~15 kyr) than can be simulated in laboratory experiments and (2) previous studies have determined the rates and mass-balances of de- dolomitization and other geochemical reactions controlling solute evolution along the flow path. Reactions important for changing the concentration and isotope composition of Mg include dolomite dissolution, Mg-for- Na ion exchange, calcite precipitation, and isotope exchange. δ26Mg values within the recharge region (0-17 km along flow path) vary between -1.08 and -1.63 permil, and then remain essentially constant at -1.408±0.010 permil(1σ, 5 samples) from 17 to 189 km. A final sample at 236 km shows an increase to -1.09 permil. Either mixing between different recharge waters or rapid isotope exchange between infiltrating waters and dolomite could control δ26Mg variability between 0 and 17 km. Likewise, reactive transport modeling suggests that preferential uptake of 24Mg during Mg-for-Na ion exchange might cause an increase in δ26Mg between 189 and 236 km. However, unchanging δ26Mg values observed throughout most of the aquifer clearly demonstrate that Mg isotopes are not fractionated during

  20. Hydrochemical and isotopic investigation of atmospheric precipitation in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Yuanzheng, E-mail: diszyz@163.com [College of Water Sciences, Beijing Normal University, Beijing 100875 (China); Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875 (China); Wang, Jinsheng, E-mail: wangjs@bnu.edu.cn [College of Water Sciences, Beijing Normal University, Beijing 100875 (China); Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875 (China); Zhang, Yang [College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049 (China); Teng, Yanguo; Zuo, Rui; Huan, Huan [College of Water Sciences, Beijing Normal University, Beijing 100875 (China); Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875 (China)

    2013-07-01

    Precipitation water samples were collected at an urban site in Beijing in a hydrological cycle (July 2008–July 2009), and analyzed for TDS, total alkalinity, total hardness, free CO{sub 2}, soluble SiO{sub 2}, bromide, sulfide, phosphate, major ions (K{sup +}, Na{sup +}, Ca{sup 2+}, Mg{sup 2+}, NH{sub 4}{sup +}, HCO{sub 3}{sup −}, Cl{sup −}, SO{sub 4}{sup 2−}, NO{sub 3}{sup −}), trace elements (CO{sub 3}{sup 2−}, Mn, Sr{sup 2+}, Fe{sup 2+}, Fe{sup 3+}, Al, F{sup −}, NO{sub 2}{sup −}), stable isotopes ({sup 2}H and {sup 18}O), and radioactive isotope ({sup 3}H). In addition, available published hydrochemical and isotopic data of precipitation of Beijing in the past were also collected and conjointly analyzed. Most of the parameters of samples tested varied considerably in the hydrological cycle. In general, HCO{sub 3}{sup −} and SO{sub 4}{sup 2−}, and Ca{sup 2+} and NH{sub 4}{sup +} are the dominant anions and cations, respectively. Using Na{sup +} as an indicator of marine origin, and Al for the terrestrial inputs, the proportions of major elements from sea salt and terrestrial sources were estimated by using the combination of statistical analysis methods and analogy method. More than 70.1% of Cl{sup −}, 98.1% of Ca{sup 2+}, and 93.6% of K{sup +} were non-sea-salt origin, while more than 98.4% of Na{sup +} was from marine sources. The LMWL (Local Meteoric Water Line) was obtained with an equation of δ{sup 2}H = 7.0181δ{sup 18}O + 3.5231 (‰, R{sup 2} = 0.86, n = 36), which was similar to GMWL (Global Meteoric Water Line). δ{sup 2}H, δ{sup 18}O and Δ-excess changed radically with month and season, but had no apparent seasonal effect, precipitation amount effect, and temperature effect. The annual mean values of Δ-excess for 1979 (16.5‰) and 1980 (16.3‰) were much bigger than that for 2007 (7.2‰), 2008 (2.1‰) and 2009 (4.5‰). The composition of {sup 2}H and {sup 18}O was probably intrinsically determined by the sources of water

  1. O JORNALISTA NA PESQUISA E NA ARTE

    Directory of Open Access Journals (Sweden)

    Beatriz Marocco

    2013-06-01

    Full Text Available O jornalista tem sido objeto das artes e das ciências. Nesta incisão no tema do painel “Configurações e perspectivas da pesquisa em jornalismo no Brasil em diálogo com os estudos latinoamericanos em jornalismo”, realizado no Encontro Nacional da Sociedade Brasileira de Pesquisadores em Jornalismo/SBPJor (Curitiba, 10/11/2012, reconheci que o âmbito acadêmico projeta dois tipos de ação: em rede de pesquisadores de diferentes países e regiões do mundo, com participação de países da América Latina, na pesquisa colaborativa e em projetos de investigação com outras bases de colaboração. Ambas as modalidades dialogam com a produção do cinema e da literatura – que visibiliza a grande potência do profissional para tramas e tensões. 

  2. Uranium isotopes fingerprint biotic reduction

    Science.gov (United States)

    Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J.; Weyer, Stefan; Bernier-Latmani, Rizlan

    2015-01-01

    Knowledge of paleo-redox conditions in the Earth’s history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U), i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth’s crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. Additionally, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium. PMID:25902522

  3. Iron isotopes for the layered series of the Skaergaard intrusion

    Science.gov (United States)

    Lesher, C. E.; Lundstrom, C.; Brown, E.; Huang, F.; Glessner, J. J.; Hoffmann-Barfod, G.; Thy, P.

    2009-12-01

    It has long been held that magmatic evolution of the Skaergaard intrusion involved strong iron enrichment accompanying gabbro fractionation. Continued enrichment of iron in evolved liquids following FeTi oxide saturation is problematic and has been ascribed to a number of related factors, including 1) the composition of the Skaergaard parental magma, 2) changes in oxidation conditions and proportion of fractionating FeTi oxide and silicates during the course of differentiation, and 3) the effects of liquid immiscibility. In most differentiation scenarios differences in the partitioning of Fe+2 and Fe+3 between fractionating minerals and silicate melt are considered to be key to maintaining the bulk distribution coefficient for total iron below unity, thus permitting iron enrichment during magmatic evolution. Recent experimental work [1] predicts measureable fractionation of iron isotopes between magnetite and silicate melt that can lead to enrichment of isotopically lighter iron in derivative liquids compared to magnetite-rich cumulates. This possibility suggests that a signature of FeTi oxide fractionation may be recorded in the Fe isotope composition of Skaergaard gabbros. Initial investigation of this possibility is based on the analysis of 15 average gabbros from the layered series by high resolution MC-ICPMS after digestion and separation of iron using AG1X8 resin. The δ56Fe values {= [(56Fe/54Fe)sample/(56Fe/54Fe)IRMM-014 - 1] × 1000} for this suite range from a low of 0.052 per mil to a high of 0.188 per mil with external precision better than ±0.05 per mil (1σ). While the entire variation is small we find a progressive decrease in δ56Fe by 0.09 per mil passing from Lower Zone a to the base of Upper Zone c (UZc). Within UZc δ56Fe increases rapidly to 0.188 per mil approaching the Sandwich Horizon. Forward modeling of closed system fractional crystallization using fractionation factors from [1] can account for the observed decrease in δ56Fe by Fe

  4. CO Isotopes in Planetary Nebulae

    OpenAIRE

    Balser, Dana S.; McMullin, Joseph P.; Wilson, T. L.

    2002-01-01

    Standard stellar evolution theory is inconsistent with the observed isotopic carbon ratio, 12C/13C, in evolved stars. This theory is also inconsistent with the 3He/H abundance ratios observed in Galactic HII regions, when combined with chemical evolution theory. These discrepancies have been attributed to an extra, non-standard mixing which further processes material during the RGB and should lower both the 12C/13C and 3He/H abundance ratios for stars with masses < 2 solar masses. Measurement...

  5. Microbiological testing of devices used in maintaining peripheral venous catheters.

    Science.gov (United States)

    Rossini, Fernanda de Paula; Andrade, Denise de; Santos, Lissandra Chaves de Sousa; Ferreira, Adriano Menis; Tieppo, Caroline; Watanabe, Evandro

    2017-05-15

    to evaluate the use of peripheral venous catheters based on microbiological analysis of devices (dressing and three-way stopcocks) and thus contribute to the prevention and infection control. this was a prospective study of microbiological analysis of 30 three-way stopcocks (external surfaces and lumens) and 30 dressing used in maintaining the peripheral venous catheters of hospitalized adult patients. all external surfaces, 40% of lumens, and 86.7% of dressing presented bacterial growth. The main species isolated in the lumen were 50% coagulase-negative Staphylococcus, 14.3% Staphylococcus aureus, and 14.3% Pseudomonas aeruginosa. Fifty nine percent of multidrug-resistant bacteria were isolated of the three-way stopcocks, 42% of the lumens, and 44% of the dressing with a predominance of coagulase-negative Staphylococcus resistant to methicillin. Besides, 18% gram-negative bacteria with resistance to carbapenems were identified from multidrug-resistant bacteria on the external surfaces of the three-way stopcocks. it is important to emphasize the isolation of coagulase-negative Staphylococcus and gram-negative bacteria resistant to methicillin and carbapenems in samples of devices, respectively, which reinforces the importance of nursing care in the maintenance of the biologically safe environment as well as prevention and infection control practices. avaliar o uso de cateteres venosos periféricos com base em análises microbiológicas de dispositivos (curativos e torneiras de três vias - T3Vs) e assim contribuir para a prevenção e controle de infecção. estudo prospectivo de análise microbiológica de 30 T3Vs (superfícies externas e lúmens) e 30 curativos utilizados na manutenção dos cateteres venosos periféricos de pacientes adultos hospitalizados. todas as superfícies externas, 40% dos lúmens e 86,7% dos curativos apresentaram crescimento bacteriano. As principais espécies isoladas no lúmen foram 50% Staphylococcus coagulase-negativa, 14

  6. Molecular Cloning and Characterization of Porcine Na+/K+-ATPase Isoforms α1, α2, α3 and the ATP1A3 Promoter

    DEFF Research Database (Denmark)

    Henriksen, Carina; Kjaer-Sorensen, Kasper; Einholm, Anja Pernille

    2013-01-01

    Na+/K+-ATPase maintains electrochemical gradients of Na+ and K+ essential for a variety of cellular functions including neuronal activity. The α-subunit of the Na+/K+-ATPase exists in four different isoforms (α1–α4) encoded by different genes. With a view to future use of pig as an animal model...

  7. Exploring the isotopic niche: isotopic variance, physiological incorporation, and the temporal dynamics of foraging

    Directory of Open Access Journals (Sweden)

    Justin Douglas Yeakel

    2016-01-01

    Full Text Available Consumer foraging behaviors are dynamic, changing in response to prey availability, seasonality, competition, and even the consumer's physiological state. The isotopic composition of a consumer is a product of these factors as well as the isotopic `landscape' of its prey, i.e. the isotopic mixing space. Stable isotope mixing models are used to back-calculate the most likely proportional contribution of a set of prey to a consumer's diet based on their respective isotopic distributions, however they are disconnected from ecological process. Here we build a mechanistic framework that links the ecological and physiological processes of an individual consumer to the isotopic distribution that describes its diet, and ultimately to the isotopic composition of its own tissues, defined as its `isotopic niche’. By coupling these processes, we systematically investigate under what conditions the isotopic niche of a consumer changes as a function of both the geometric properties of its mixing space and foraging strategies that may be static or dynamic over time. Results of our derivations reveal general insight into the conditions impacting isotopic niche width as a function of consumer specialization on prey, as well as the consumer's ability to transition between diets over time. We show analytically that moderate specialization on isotopically unique prey can serve to maximize a consumer's isotopic niche width, while temporally dynamic diets will tend to result in peak isotopic variance during dietary transitions. We demonstrate the relevance of our theoretical findings by examining a marine system composed of nine invertebrate species commonly consumed by sea otters. In general, our analytical framework highlights the complex interplay of mixing space geometry and consumer dietary behavior in driving expansion and contraction of the isotopic niche. Because this approach is established on ecological mechanism, it is well-suited for enhancing the

  8. Silicon isotope fractionation during magmatic differentiation

    Science.gov (United States)

    Savage, Paul S.; Georg, R. Bastian; Williams, Helen M.; Burton, Kevin W.; Halliday, Alex N.

    2011-10-01

    The Si isotopic composition of Earth's mantle is thought to be homogeneous (δ 30Si = -0.29 ± 0.08‰, 2 s.d.) and not greatly affected by partial melting and recycling. Previous analyses of evolved igneous material indicate that such rocks are isotopically heavy relative to the mantle. To understand this variation, it is necessary to investigate the degree of Si isotopic fractionation that takes place during magmatic differentiation. Here we report Si isotopic compositions of lavas from Hekla volcano, Iceland, which has formed in a region devoid of old, geochemically diverse crust. We show that Si isotopic composition varies linearly as a function of silica content, with more differentiated rocks possessing heavier isotopic compositions. Data for samples from the Afar Rift Zone, as well as various igneous USGS standards are collinear with the Hekla trend, providing evidence of a fundamental relationship between magmatic differentiation and Si isotopes. The effect of fractionation has been tested by studying cumulates from the Skaergaard Complex, which show that olivine and pyroxene are isotopically light, and plagioclase heavy, relative to the Si isotopic composition of the Earth's mantle. Therefore, Si isotopes can be utilised to model the competing effects of mafic and felsic mineral fractionation in evolving silicate liquids and cumulates. At an average SiO 2 content of ˜60 wt.%, the predicted δ 30Si value of the continental crust that should result from magmatic fractionation alone is -0.23 ± 0.05‰ (2 s.e.), barely heavier than the mantle. This is, at most, a maximum estimate, as this does not take into account weathered material whose formation drives the products toward lighter δ 30Si values. Mass balance calculations suggest that removal of continental crust of this composition from the upper mantle will not affect the Si isotopic composition of the mantle.

  9. Radium geochemistry in Na-Cl type groundwater in Niigata Prefecture, Japan.

    Science.gov (United States)

    Tomita, Junpei; Satake, Hiroshi; Fukuyama, Taijiro; Sasaki, Keiichi; Sakaguchi, Aya; Yamamoto, Masayoshi

    2010-03-01

    Radium isotopes in 23 Na-Cl type groundwater sampled mainly from deep wells in Niigata Prefecture, which is the site of the largest oil- and gas-fields in Japan, were measured along with U isotopes, chemical components and hydrogen and oxygen isotope ratios to elucidate the distribution and behavior of Ra in a brackish environment underground. Also analyzed were U and Th isotopes in 38 rock samples collected from outcrops at 17 locations. Ra-226 concentrations (8.86-1637 mBq kg(-1)) of groundwater samples roughly correlated with total dissolved solid (TDS) concentrations and other alkaline earth contents. Their (228)Ra/(226)Ra activity ratios (0.32-5.2) were similar to or higher than the (232)Th/(238)U activity ratios (0.6-1.7) in the rocks. The most likely transport mechanism of Ra isotopes into groundwater was due to their alpha-recoil from the solid phase, probably from the water-rock interface where Th isotopes had accumulated, and adsorption/desorption reaction based on the increase in (226)Ra contents with TDS.

  10. A cryogenic optical feedthrough using polarization maintaining fibers.

    Science.gov (United States)

    Nelson, M J; Collins, C J; Speake, C C

    2016-03-01

    Polarization maintaining optical fibers can be used to transmit linearly polarized light over long distances but their use in cryogenic environments has been limited by their sensitivity to temperature changes and associated mechanical stress. We investigate experimentally how thermal stresses affect the polarization maintaining fibers and model the observations with Jones matrices. We describe the design, construction, and testing of a feedthrough and fiber termination assembly that uses polarization maintaining fiber to transmit light from a 633 nm HeNe laser at room temperature to a homodyne polarization-based interferometer in a cryogenic vacuum. We report on the efficiency of the polarization maintaining properties of the feedthrough assembly. We also report that, at cryogenic temperatures, the interferometer can achieve a sensitivity of 8 × 10(-10) rad/√Hz at 0.05 Hz using this feedthrough.

  11. 36 CFR 1222.34 - How must agencies maintain records?

    Science.gov (United States)

    2010-07-01

    ... ADMINISTRATION RECORDS MANAGEMENT CREATION AND MAINTENANCE OF FEDERAL RECORDS Agency Recordkeeping Requirements... organizing and storing records; (b) Maintain electronic, audiovisual and cartographic, and microform records in accordance with 36 CFR parts 1236, 1237, and 1238 of this subchapter, respectively; (c)...

  12. Developing maintainability for fusion power systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Zahn, H.S.; Mantz, H.C.; Curtis, C.T.; Buchheit, R.J.; Green, W.M.; Zuckerman, D.S.

    1979-11-01

    The overall purpose of the study is to identify design features of fusion power reactors which contribute to the achievement of high levels of maintainability. Previous phases evaluated several commercial tokamak reactor design concepts. This final phase compares the maintainability of a tandem mirror reactor (TMR) commercial conceptual design with the most maintainable tokamak concept selected from earlier work. A series of maintainability design guidelines and desirable TMR design features are defined. The effects of scheduled and unscheduled maintenance for most of the reactor subsystems are defined. The comparison of the TMR and tokamak reactor maintenance costs and availabilities show that both reactors have similar costs for scheduled maintenance at 19.4 and 20.8 million dollars annually and similar scheduled downtime availability impacts, achieving approximate availabilities of 79% at optimized maintenance intervals and cost of electricity.

  13. Maintaining Students’ Involvement in a Math Lecture Using Countdown Timers

    National Research Council Canada - National Science Library

    Ann Krizzel A. Aban; Lauro L. Fontanil

    2015-01-01

    ...), to deliver their lectures. The non-stop use of these softwares, however, seems to have negative effects on the students when it comes to maintaining their involvement in a lecture discussion for they tend to be more passive spectators...

  14. Allocating SMART Reliability and Maintainability Goals to NASA Ground Systems

    Science.gov (United States)

    Gillespie, Amanda; Monaghan, Mark

    2013-01-01

    This paper will describe the methodology used to allocate Reliability and Maintainability (R&M) goals to Ground Systems Development and Operations (GSDO) subsystems currently being designed or upgraded.

  15. Coastal Maintained Channels in US waters as of May 2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This layer shows coastal channels and waterways that are maintained and surveyed by the U.S. Army Corps of Engineers (USACE). These channels are necessary...

  16. An Improved Functional Hierarchy Frame Model for System Maintainability

    Institute of Scientific and Technical Information of China (English)

    CHEN Dai-Lin; CHEN Dong-lin; WANG Ru-gen; ZHU Xue-ping

    2003-01-01

    By means of analogy, this paper analyses the present functional hierarchy frame model for system maintainability, and presents an improved model. Practical application indicates that the improved model is visualized, more convenient and perfected over the pervious models.

  17. Stable isotope utilization methodology; Methodologie de l`emploi des isotopes stables

    Energy Technology Data Exchange (ETDEWEB)

    Roth, E. [Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)

    1994-12-31

    The various applications of stable isotope utilization are reviewed, as a function of their specific properties: poly-isotopic abundance modification is used for tracer applications; the accurate measurement of the stable isotope abundance may be applied to isotopic dilution for ultra-trace measurement, physical constant determination, fluid volume and concentration measurement; isotopic effects, such as reaction equilibrium differences are used for separation and identification of molecule active centers (pharmacology, paleoclimatology, hydrogeological studies) while reaction rate differences (competitive and non competitive methods) are used for the study of reaction mechanisms, such as enzymatic reactions. Analysis techniques (mass spectrometry, nuclear magnetic resonance, optical methods) are reviewed. 2 figs., 18 refs.

  18. Performance comparison of MoNA and LISA neutron detectors

    Science.gov (United States)

    Purtell, Kimberly; Rethman, Kaitlynne; Haagsma, Autumn; Finck, Joseph; Smith, Jenna; Snyder, Jesse

    2010-11-01

    In 2002 eight primarily undergraduate institutions constructed and tested the Modular Neutron Array (MoNA) which has been used to detect high energy neutrons at the National Superconducting Cyclotron Laboratory (NSCL). Nine institutions have now designed, constructed and tested the Large-area multi-Institutional Scintillator Array (LISA) neutron detector which will be used at the NSCL and the future Facility for Rare Isotope Beams (FRIB). Both detectors are comprised of 144 detector modules. Each module is a 200 x 10 x 10 cm^3 bar organic plastic scintillator with a photomultiplier tube mounted on each end. Using cosmic rays and a gamma source, we compared the performance of MoNA and LISA by using the same electronics to check light attenuation, position resolution, rise times, and cosmic ray peak widths. Results will be presented.

  19. Fingerprinting the temperature and fluid source of fracture-filling calcite in geothermal systems using clumped isotopes

    Science.gov (United States)

    MacDonald, John M.; Davies, Amelia; Faithfull, John; Holdsworth, Chris; Newton, Michael; Williamson, Sam; John, Cedric

    2017-04-01

    Geothermal energy production relies on maintaining open fractures within the rock through which fluids can flow, but precipitation of minerals in fractures can modify and reduce fluid flow. Most geothermal fluids are rich in dissolved material, and readily precipitate minerals such as calcite within fracture systems. Such mineral deposition can be a key limiting factor in viable geothermal energy production. We need to better understand the relationship between fluid temperatures, mineral precipitation, and fracture filling in such systems. Clumped isotopes offer a new way of characterising the temperature and fluid source of fracture-filling calcite. This technique is based on the thermodynamic relationship between carbonate mineral growth temperature and the abundance of chemical bonding ("clumping") between 13C and 18O isotopes (expressed as Δ47) within single carbonate ions (e.g. Eiler, 2007). In the gas phase, isotopic exchange between CO2 molecules and water is continuous and so CO2 gas will record the ambient fluid temperature. When the CO2 is trapped in a solid mineral phase, the isotope ratio is fixed. As a result, clumped isotopes will record the temperature of crystallisation, enabling the application of clumped isotope palaeothermometry to a range of geological problems. Samples from active geothermal fields (the Kawerau geothermal field, New Zealand (McNamara et al., 2017)) and analogues to basaltic geothermal systems in Western Scotland have been analysed with clumped isotopes. We present petrography, δ13C and δ18O, and clumped isotope data from these samples to show how clumped isotopes can fingerprint the temperature and fluid source of fracture-filling calcite in geothermal systems. Having this understanding of fracture filling conditions can lead to focused development of remediation measures. References Eiler, J. M., 2007. EPSL 262(3-4), 309-327. McNamara, D. D., Lister, A., Prior, D. J., 2016. JVGR 323, 38-52.

  20. Band and loop space maintainer--made easy.

    Science.gov (United States)

    Nayak, U A; Loius, J; Sajeev, R; Peter, J

    2004-09-01

    Space maintainers have been used in Pediatric Dentistry for many years. The use of these appliances, however, in terms of indications, contraindications, design and construction has gained little attention from researchers. This paper highlights the construction of a new technique of fabrication of band and loop space maintainer. The advantages of this new Direct technique or Single sitting technique over the conventional technique are discussed.

  1. Banded vs Bonded Space Maintainers: Finding Better Way Out

    OpenAIRE

    Setia, Vikas; Kumar Pandit, Inder; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika

    2014-01-01

    ABSTRACT Objectives: Of this in vivo study was to evaluate various space maintainers in terms of survival rate, gingival health and presence of caries. Design: A total of 60 extraction sites in the age group of 4 to 9 years were divided into four groups and different space maintainers were placed in them viz (conventional band and loop, prefabricated band with custom made loop, Ribbond, Super splint). Results: Prefabricated bands with custom made loop showed maximum success rates (84.6%), whi...

  2. Vaginose Bacteriana na Colpocitologia

    OpenAIRE

    Consolaro,Márcia Edilaine Lopes; Suzuki, Linda Emiko

    2008-01-01

    A flora vaginal representa um ecossistema dinâmico influenciado por fatores diversos, existindo mecanismos desconhecidos que alteram esta flora, desencadeando distúrbios como vaginoses bacterianas. Este trabalho teve como objetivo avaliar a incidência de vaginoses bacterianas detectadas por colpocitologia na população atendida pelo Setor de Citologia Clínica do Laboratório de Ensino e Pesquisa em Análises Clínicas (LEPAC) da Univers...

  3. Preparing for NA4

    CERN Multimedia

    1977-01-01

    Here, in one of the EF workshop, Albert Duchêne works on a pretty piece of mechanics. A few others await to be attended on the left. There are indications that the pipes were meant to house the carbon target (subdivided in eight sections) to be installed inside the toroid magnet of the NA4 experiment. The external strips were designed to possibly correct the magnetic field (???).

  4. Isotope Separation and Decay Energy Calculation for LISA Commissioning Experiment

    Science.gov (United States)

    Taylor, Nathaniel; Barker, Alyson; Garrett, Sierra; Rogers, Warren F.; MoNA Collaboration

    2013-10-01

    The commissioning experiment for the Large multi-Institutional Scintillator Array (LISA) was designed to investigate properties of neutron-unstable excited states of the 24O. The array is located at the NSCL, MSU and is used in conjunction with the Modular Neutron Array (MoNA) and the Sweeper Magnet. Oxygen fragments produced by the 26F secondary beam incident on a Be target are directed through the Sweeper Chamber which includes two tracking CRDC detectors, an ion chamber, and a thin and thick scintillator. Plotting the fragment's trajectory position vs. angle vs. time of flight allows for separation of the individual 22 , 23 , and 24 O isotopes, necessary for the calculation of the decay properties of individual states. Anomalous features in the fragments' emittance distribution, believed to result from little understood issues with the tracking detectors, required that we adopt a slightly different approach than that developed recently by the collaboration. Once the isotopes are successfully separated, decay energies are calculated by applying mass-invariant decay spectroscopy by associating the fragment's precise trajectory (determined by inverse-tracking through the Sweeper Magnet) and energy with those of the emitted neutron. Work supported by NSF grant PHY-1101745.

  5. Maintaining dental records: Are we ready for forensic needs?

    Directory of Open Access Journals (Sweden)

    Madhusudan Astekar

    2011-01-01

    Full Text Available Context: Dental remains are usually the last to get destroyed among body parts after death. They may be useful for personal identification in cases of mass disasters and decomposed unidentified bodies. Dental records may help in the identification of suspects in criminal investigations and in medicolegal cases. Maintenance of dental records is legally mandatory in most of the European and American countries. Unfortunately, the law is not very clear in India, and the awareness is very poor. Aims: To assess the awareness regarding the dental record maintenance among dentists in Rajasthan, to deduce the quality of average dental records kept by them and to evaluate the potential use of their maintained records, in any of forensic or medicolegal cases. Settings and Design: A cross-sectional survey was conducted among 100 dental practitioners of different cities in Rajasthan, India. Materials and Methods: Data were collected through a structured questionnaire, which was responded by the study population in the course of a telephonic interview. The questionnaire addressed on the mode of maintaining dental records in their regular practice. Statistical Analysis Used: The data so gathered were subjected for descriptive analysis. Results: As for knowledge or awareness about maintaining dental records, surprisingly a very low percentile (about 38% of surveyed dentists maintained records. Sixty-two percent of the dentists were maintaining no records at all. Conclusion : Nonmaintenance or poor quality of records maintained indicates that the dentists in Rajasthan are not prepared for any kind of forensic and medicolegal need if it arises.

  6. ISOTOPES

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    1 A New Therapeutic Agent for Radiation Synovectomy: Preparation of 166Ho-EDTMP-HA Bai Hongsheng Jin Xiaohai Du Jin Wang Fan Chen Daming Fan Hongqiang Cheng Zhen In order to treat the patient with inflammatory synovial disease, HA particle is labeled with 166Ho by EDTMP under the condition of pH6.0-8.0 and vibration time 15 min, its labeling efficiency is more than 98%, the size of particle is mainly in the range of 2-5 μm. The absorbed capacity is 5 mg Ho per 1g HA. Study on stability of 166Ho-EDTMP-HA in vitro shows that loss of 166Ho is less than 2% for166Ho-EDTMP-HA incubated 72 h in the 0.9% saline and 1% BSA solution at 37 ℃ .Biodistribution in vivo and extra articular leakage are investigated following injection of 166Ho-EDTMP-HA into knee of normal rabbits. The experimental results show that the extra leakage of 166Ho-EDTMP-HA is 0.32% at 48 h post-injection, most of 166Ho radioactivity leaked from the knee joint is excreted in the urine. 99% of 166Ho radioactivity is retained in the knee joint of rabbits. Thereby 166Ho-EDTMP-HA, as a new therapeutical agent of radiation synovectomy, had a value of further clinical study.

  7. The isotopic dipole moment of HDO

    Energy Technology Data Exchange (ETDEWEB)

    Assafrao, Denise; Mohallem, Jose R [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, CP 702, 30123-970, Belo Horizonte, MG (Brazil)

    2007-03-14

    An adiabatic variational approximation is used to study the monodeuterated water molecule, HDO, accounting for the isotopic effect. The isotopic dipole moment, pointing from D to H, is then calculated for the first time, yielding (1.5 {+-} 0.1) x 10{sup -3} Debye, being helpful in the interpretation of experiments. (fast track communication)

  8. Magnesium isotope geochemistry in arc volcanism

    Science.gov (United States)

    Teng, Fang-Zhen; Hu, Yan; Chauvel, Catherine

    2016-06-01

    Incorporation of subducted slab in arc volcanism plays an important role in producing the geochemical and isotopic variations in arc lavas. The mechanism and process by which the slab materials are incorporated, however, are still uncertain. Here, we report, to our knowledge, the first set of Mg isotopic data for a suite of arc lava samples from Martinique Island in the Lesser Antilles arc, which displays one of the most extreme geochemical and isotopic ranges, although the origin of this variability is still highly debated. We find the δ26Mg of the Martinique Island lavas varies from -0.25 to -0.10, in contrast to the narrow range that characterizes the mantle (-0.25 ± 0.04, 2 SD). These high δ26Mg values suggest the incorporation of isotopically heavy Mg from the subducted slab. The large contrast in MgO content between peridotite, basalt, and sediment makes direct mixing between sediment and peridotite, or assimilation by arc crust sediment, unlikely to be the main mechanism to modify Mg isotopes. Instead, the heavy Mg isotopic signature of the Martinique arc lavas requires that the overall composition of the mantle wedge is buffered and modified by the preferential addition of heavy Mg isotopes from fluids released from the altered subducted slab during fluid-mantle interaction. This, in turn, suggests transfer of a large amount of fluid-mobile elements from the subducting slab to the mantle wedge and makes Mg isotopes an excellent tracer of deep fluid migration.

  9. Magnesium isotope geochemistry in arc volcanism.

    Science.gov (United States)

    Teng, Fang-Zhen; Hu, Yan; Chauvel, Catherine

    2016-06-28

    Incorporation of subducted slab in arc volcanism plays an important role in producing the geochemical and isotopic variations in arc lavas. The mechanism and process by which the slab materials are incorporated, however, are still uncertain. Here, we report, to our knowledge, the first set of Mg isotopic data for a suite of arc lava samples from Martinique Island in the Lesser Antilles arc, which displays one of the most extreme geochemical and isotopic ranges, although the origin of this variability is still highly debated. We find the δ(26)Mg of the Martinique Island lavas varies from -0.25 to -0.10, in contrast to the narrow range that characterizes the mantle (-0.25 ± 0.04, 2 SD). These high δ(26)Mg values suggest the incorporation of isotopically heavy Mg from the subducted slab. The large contrast in MgO content between peridotite, basalt, and sediment makes direct mixing between sediment and peridotite, or assimilation by arc crust sediment, unlikely to be the main mechanism to modify Mg isotopes. Instead, the heavy Mg isotopic signature of the Martinique arc lavas requires that the overall composition of the mantle wedge is buffered and modified by the preferential addition of heavy Mg isotopes from fluids released from the altered subducted slab during fluid-mantle interaction. This, in turn, suggests transfer of a large amount of fluid-mobile elements from the subducting slab to the mantle wedge and makes Mg isotopes an excellent tracer of deep fluid migration.

  10. Advanced Mass Spectrometers for Hydrogen Isotope Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Chastagner, P.

    2001-08-01

    This report is a summary of the results of a joint Savannah River Laboratory (SRL) - Savannah River Plant (SRP) ''Hydrogen Isotope Mass Spectrometer Evaluation Program''. The program was undertaken to evaluate two prototype hydrogen isotope mass spectrometers and obtain sufficient data to permit SRP personnel to specify the mass spectrometers to replace obsolete instruments.

  11. Applications of stable isotopes in clinical pharmacology

    NARCIS (Netherlands)

    Schellekens, Reinout C A; Stellaard, Frans; Woerdenbag, Herman J; Frijlink, Henderik W; Kosterink, Jos G W

    2011-01-01

    This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the pharmacok

  12. Isotopic niches support the resource breadth hypothesis

    Science.gov (United States)

    Rader, Jonathan A.; Newsome, Seth D.; Sabat, Pablo; Chesser, R. Terry; Dillon, Michael E.; Martinez del Rio, Carlos

    2017-01-01

    Because a broad spectrum of resource use allows species to persist in a wide range of habitat types, and thus permits them to occupy large geographical areas, and because broadly distributed species have access to more diverse resource bases, the resource breadth hypothesis posits that the diversity of resources used by organisms should be positively related with the extent of their geographic ranges.We investigated isotopic niche width in a small radiation of South American birds in the genus Cinclodes. We analysed feathers of 12 species of Cinclodes to test the isotopic version of the resource breadth hypothesis and to examine the correlation between isotopic niche breadth and morphology.We found a positive correlation between the widths of hydrogen and oxygen isotopic niches (which estimate breadth of elevational range) and widths of the carbon and nitrogen isotopic niches (which estimates the diversity of resources consumed, and hence of habitats used). We also found a positive correlation between broad isotopic niches and wing morphology.Our study not only supports the resource breadth hypothesis but it also highlights the usefulness of stable isotope analyses as tools in the exploration of ecological niches. It is an example of a macroecological application of stable isotopes. It also illustrates the importance of scientific collections in ecological studies.

  13. Applications of stable isotopes in clinical pharmacology

    NARCIS (Netherlands)

    Schellekens, Reinout C A; Stellaard, Frans; Woerdenbag, Herman J; Frijlink, Henderik W; Kosterink, Jos G W

    2011-01-01

    This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the

  14. Atomic lithium vapor laser isotope separation

    CERN Document Server

    Olivares, I E

    2002-01-01

    An atomic vapor laser isotope separation in lithium was performed using tunable diode lasers. The method permits also the separation of the isotopes between the sup 6 LiD sub 2 and the sup 7 LiD sub 1 lines using a self-made mass separator which includes a magnetic sector and an ion beam designed for lithium. (Author)

  15. Isotope Program Report June FY2016

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Jr, Benjamin E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Egle, Brian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    Isotope Program Monthly Highlights are briefly described. These include data on isotopes shipped, updates on equipment fabrication and testing, a potential new approach for nondestructive measurement of the amount of Cf-252 deposited on a surface, and efforts to recover and purify uranium-234 obtained from old PuBe sources.

  16. Phosphorus dynamics in soils irrigated with reclaimed waste water or fresh water - A study using oxygen isotopic composition of phosphate

    Science.gov (United States)

    Zohar, I.; Shaviv, A.; Young, M.; Kendall, C.; Silva, S.; Paytan, A.

    2010-01-01

    Transformations of phosphate (Pi) in different soil fractions were tracked using the stable isotopic composition of oxygen in phosphate (??18Op) and Pi concentrations. Clay soil from Israel was treated with either reclaimed waste water (secondary, low grade) or with fresh water amended with a chemical fertilizer of a known isotopic signature. Changes of ??18Op and Pi within different soil fractions, during a month of incubation, elucidate biogeochemical processes in the soil, revealing the biological and the chemical transformation impacting the various P pools. P in the soil solution is affected primarily by enzymatic activity that yields isotopic equilibrium with the water molecules in the soil solution. The dissolved P interacts rapidly with the loosely bound P (extracted by bicarbonate). The oxides and mineral P fractions (extracted by NaOH and HCl, respectively), which are considered as relatively stable pools of P, also exhibited isotopic alterations in the first two weeks after P application, likely related to the activity of microbial populations associated with soil surfaces. Specifically, isotopic depletion which could result from organic P mineralization was followed by isotopic enrichment which could result from preferential biological uptake of depleted P from the mineralized pool. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with reclaimed waste water compared to the fertilizer treated soil. ?? 2010 Elsevier B.V.

  17. Second international conference on isotopes. Conference proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, C.J. [ed.

    1997-10-01

    The Second International Conference on Isotopes (2ICI) was hosted by the Australian Nuclear Association in Sydney, NSW, Australia. The Theme of the Second Conference: Isotopes for Industry, Health and a Better Environment recognizes that isotopes have been used in these fields successfully for many years and offer prospects for increasing use in the future. The worldwide interest in the use of research reactors and accelerators and in applications of stable and radioactive isotopes, isotopic techniques and radiation in industry, agriculture, medicine, environmental studies and research in general, was considered. Other radiation issues including radiation protection and safety were also addressed. International and national overviews and subject reviews invited from leading experts were included to introduce the program of technical sessions. The invited papers were supported by contributions accepted from participants for oral and poster presentation. A Technical Exhibition was held in association with the Conference. This volume contains the full text or extended abstracts of papers number 61- to number 114

  18. A epilepsia na neurocisticercose

    Directory of Open Access Journals (Sweden)

    Luís Marques-Assis

    1972-12-01

    Full Text Available Foram estudados 131 casos de epilepsia com etiologia cisticercótica comprovada. A idade variou de 2 a 68 anos; 75 pacientes eram de sexo masculino e 56 de sexo feminino; 117 eram brancos, 10 pardos, três pretos e um amarelo. A idade de início da doença predominou na primeira década. O estudo foi feito em relação ao tipo de epilepsia, ao tempo decorrido após a primeira crise, à freqüência das crises e ao eletrencefalograma relativamente às epilepsias em geral. Investigação foi feita também em relação à cefaléia, aos achados neurológicos, liquóricos, radiológicos simples e contrastados e anátomo-patológicos. A análise dos resultados permitiu aos autores as seguintes conclusões: 1 No grupo de neurocisticercose o início da doença predominou na primeira e a partir da quarta década em relação às epilepsias em geral. 2 Dentre as manifestações clínicas predominaram as formas convulsivas da doença (61%, sendo as crises bravas-jacksonianas as menos freqüentes (4%; quando comparadas com as epilepsias em geral, verifica-se incidência menor das convulsões generalizadas na neurocisticercose. 3 Quanto ao tempo de doença, verifica-se predomínio das formas de duração mais curta (um ano ou menos na neurocisticercose. 4 A severidade da epilepsia, traduzida pela freqüência das crises, foi menor no grupo com neurocisticercose. 5 Excluídos os casos com anormalidades eletrencefalográficas contínuas, foram encontrados maiores índices percentuais de EEG normal na neurocisticercose que nas epilepsias em geral. 6 A cefaléia estava presente em 68% dos casos, assumindo caráter paroxístico na maior parte (78%; em 67% dos casos com cefaléia paroxística não havia concomitantemente sinais de hipertensão intracraniana; nos casos com cefaléia contínua, em apenas dois (13% esses sinais não estavam presentes. 7 Na maior parte dos casos (62% as manifestações epilépticas se apresentaram isoladamente, sem sinais neurol

  19. Manus Water Isotope Investigation Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Conroy, Jessica L [University of Illinois, Urbana-Champaign; Cobb, Kim M [Georgia Institute of Technology; Noone, David [University of Colorado, Boulder

    2016-03-01

    The objective of this field campaign was to investigate climatic controls on the stable isotopic composition of water vapor, precipitation, and seawater in the western tropical Pacific. Simultaneous measurements of the stable isotopic composition of vapor and precipitation from April 28 to May 8, 2013, at the Manus Tropical Western Pacific Atmospheric Radiation Measurement site, provided several key insights into the nature of the climate signal archived in precipitation and vapor isotope ratios. We observed a large shift from lower to higher isotopic values in vapor and precipitation because of the passage of a mesoscale convective system west of the site and a transition from a regional stormy period into a more quiescent period. During the quiescent period, the stable isotopic composition of vapor and precipitation indicated the predominance of oceanic evaporation in determining the isotopic composition of boundary-layer vapor and local precipitation. There was not a consistent relationship between intra-event precipitation amount at the site and the stable isotopic composition of precipitation, thus challenging simplified assumptions about the isotopic “amount effect” in the tropics on the time scale of individual storms. However, some storms did show an amount effect, and deuterium excess values in precipitation had a significant relationship with several meteorological variables, including precipitation, temperature, relative humidity, and cloud base height across all measured storms. The direction of these relationships points to condensation controls on precipitation deuterium excess values on intra-event time scales. The relationship between simultaneous measurements of vapor and precipitation isotope ratios during precipitation events indicates the ratio of precipitation-to-vapor isotope ratios can diagnose precipitation originating from a vapor source unique from boundary-layer vapor and rain re-evaporation.

  20. Lithium isotope behaviour during weathering in the Ganges Alluvial Plain

    Science.gov (United States)

    Pogge von Strandmann, Philip A. E.; Frings, Patrick J.; Murphy, Melissa J.

    2017-02-01

    The Ganges river system is responsible for the transportation of a large flux of dissolved materials derived from Himalayan weathering to the oceans. Silicate weathering-driven cooling resulting from uplift of the Himalayas has been proposed to be a key player in Cenozoic climate variation. This study has analysed Li isotope (δ7Li) ratios from over 50 Ganges river waters and sediments, in order to trace silicate weathering processes. Sediments have δ7Li of ∼0‰, identical to bulk continental crust, however suspended sediment depth profiles do not display variations associated with grain size that have been observed in other large river systems. Dissolved δ7Li are low (∼11‰) in the Ganges headwaters, but reach a constant value of 21 ± 1.6‰ within a relatively short distance downstream, which is then maintained for almost 2000 km to the Ganges mouth. Given that Li isotopes are controlled by the ratio of primary mineral dissolution to secondary mineral formation, this suggests that the Ganges floodplain is at steady-state in terms of these processes for most of its length. Low δ7Li in the mountainous regions suggest silicate weathering is therefore at its most congruent where uplift and fresh silicate exposure rates are high. However, there is no correlation between δ7Li and the silicate weathering rate in these rivers, suggesting that Li isotopes cannot be used as a weathering-rate tracer, although they do inform on weathering congruency and intensity. The close-to-constant δ7Li values for the final 2000 km of Ganges flow also suggest that once the size of the alluvial plain reached more than ∼500 km (the flow distance after which riverine δ7Li stops varying), the Ganges exerted little influence on the changing Cenozoic seawater δ7Li, because riverine δ7Li attained a near steady-state composition.

  1. A structural overview of the plasma membrane Na+,K+-ATPase and H+-ATPase ion pumps

    DEFF Research Database (Denmark)

    Morth, Jens Preben; Pedersen, Bjørn Panella; Buch-Pedersen, Morten Jeppe

    2011-01-01

    Plasma membrane ATPases are primary active transporters of cations that maintain steep concentration gradients. The ion gradients and membrane potentials derived from them form the basis for a range of essential cellular processes, in particular Na(+)-dependent and proton-dependent secondary tran......(+),K(+)-ATPase maintains a Na(+) and K(+) gradient in animal cells. Structural information provides insight into the function of these two distinct but related P-type pumps....

  2. Evidence From Hydrogen Isotopes in Meteorites for a Martian Permafrost

    Science.gov (United States)

    Usui, T.; Alexander, C. M. O'D.; Wang, J.; Simon, J. I.; Jones, J. H.

    2014-01-01

    Fluvial landforms on Mars suggest that it was once warm enough to maintain persistent liquid water on its surface. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. We have investigated the evolution of surface water/ ice and its interaction with the atmosphere by measurements of hydrogen isotope ratios (D/H: deuterium/ hydrogen) of martian meteorites. Hydrogen is a major component of water (H2O) and its isotopes fractionate significantly during hydrological cycling between the atmosphere, surface waters, ground ice, and polar cap ice. Based on in situ ion microprobe analyses of three geochemically different shergottites, we reported that there is a water/ice reservoir with an intermediate D/H ratio (delta D = 1,000?2500 %) on Mars. Here we present the possibility that this water/ice reservoir represents a ground-ice/permafrost that has existed relatively intact over geologic time.

  3. The geographic distribution of Sr isotopes from surface waters and soil extracts over the island of Bornholm (Denmark) – A base for provenance studies in archaeology and agriculture

    DEFF Research Database (Denmark)

    Frei, Robert; Frei, Karin Margarita

    2013-01-01

    In this paper we report the Sr isotope signatures, and Sr, Al and Na concentrations of 30 surface waters (lakes/ponds and rivers/creeks) and 19 soil sample extracts from the island of Bornholm (Denmark) and present a categorized 87Sr/86Sr value distribution map that may serve as a base for proven......In this paper we report the Sr isotope signatures, and Sr, Al and Na concentrations of 30 surface waters (lakes/ponds and rivers/creeks) and 19 soil sample extracts from the island of Bornholm (Denmark) and present a categorized 87Sr/86Sr value distribution map that may serve as a base...... for provenance studies, including archaeological migration and authenticity proof for particular food products. The Sr isotopic compositions of surface waters range from 87Sr/86Sr = 0.7097–0.7281 (average 0.7175 ± 0.0049; 1σ), whereas 0.1 M HNO3, 0.05 M HNO3, and 0.01 M CaCl2 soil extracts range from 87Sr/86Sr...... Sr isotope composition vs. Sr, Na and Al concentration relationships of soil extracts imply that lowering of the isotopic composition of leachable Sr on Bornholm results as a consequence of significant admixture to this fraction of Sr deposited as marine salts (aerosols), and that rainwater only has...

  4. Barium isotope fractionation during witherite (BaCO3) dissolution, precipitation and at equilibrium

    Science.gov (United States)

    Mavromatis, Vasileios; van Zuilen, Kirsten; Purgstaller, Bettina; Baldermann, Andre; Nägler, Thomas F.; Dietzel, Martin

    2016-10-01

    This study examines the behavior of Ba isotope fractionation between witherite and fluid during mineral dissolution, precipitation and at chemical equilibrium. Experiments were performed in batch reactors at 25 °C in 10-2 M NaCl solution where the pH was adjusted by continuous bubbling of a water saturated gas phase of CO2 or atmospheric air. During witherite dissolution no Ba isotope fractionation was observed between solid and fluid. In contrast, during witherite precipitation, caused by a pH increase, a preferential uptake of the lighter 134Ba isotopomer in the solid phase was observed. In this case, the isotope fractionation factor αwitherite-fluid is calculated to be 0.99993 ± 0.00004 (or Δ137/134Bawitherite-fluid ≈ -0.07 ± 0.04‰, 2 sd). The most interesting feature of this study, however, is that after the attainment of chemical equilibrium, the Ba isotope composition of the aqueous phase is progressively becoming lighter, indicating a continuous exchange of Ba2+ ions between witherite and fluid. Mass balance calculations indicate that the detachment of Ba from the solid is not only restricted to the outer surface layer of the solid, but affects several (∼7 unit cells) subsurface layers of the crystal. This observation comes in excellent agreement with the concept of a dynamic system at chemical equilibrium in a mineral-fluid system, denoting that the time required for the achievement of isotopic equilibrium in the witherite-fluid system is longer compared to that observed for chemical equilibrium. Overall, these results indicate that the isotopic composition of Ba bearing carbonates in natural environments may be altered due to changes in fluid composition without a net dissolution/precipitation to be observed.

  5. Lead Isotopes in Highway Runoff

    Science.gov (United States)

    Ferreira, M.; Lau, S.; Green, P. G.; Stenstrom, M. K.

    2011-12-01

    Lead (Pb) isotopes have been used extensively to study the provenance of lead pollution on air, water, and sediments. In this study, we measured Pb isotopes and Pb aqueous concentration in highway runoff in three west Los Angeles sites. Those three sites, part of a long-term study sponsored by the California Department of Transportation, represent small catchment areas, and host heavy traffic. In addition, there were no inputs of sand or salt to the highway because the sites are almost completely impervious and also due to the lack of snow to be controlled. Highway runoff from the three sites was collected for 7 storms during the 2004-2005 Winter. Grab samples were collected every 15 minutes during the first hour, and hourly afterwards. A total of 202 samples were collected and filtered into five size fractions (100μm). Aqueous concentration of Pb range from 0.08μg/L to 46.95μg/L (7.98±10.89μg/L) and it is not correlated with any of the lead isotope ratios. The 208Pb/206Pb ratio ranges from 1.983 to 2.075 (2.024±0.026) and there is no statistical difference for the mean value of the 208Pb/206Pb ratio for the four particulate size fractions (0.45-8μm, 8-20μm, 20-100μm, >100μm). However, the 208Pb/206Pb ratio of nearby soils yield 2.060±0.021 and it is statistically different from the ratios obtained for the highway runoff. This hints that the lead present in highway runoff does not come from local soils. The 207Pb/206Pb ratio ranges from 0.804 to 0.847 (0.827±0.011) and there is no statistical difference for the mean value of the 207Pb/206Pb ratio for the four particulate size fractions (0.45-8μm, 8-20μm, 20-100μm, >100μm). Surprisingly, there is also no statistical difference with the 207Pb/206Pb ratio of nearby soils (0.833±0.009).

  6. STRATEGIES OF MAINTAINING PROFICIENCY BY TEACHERS OF ENGLISH IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Junaidi Mistar, Alfan Zuhairini

    2011-10-01

    Full Text Available The objectives of the present study are four-fold: (1 to identify the types of strategies to maintain proficiency used by teachers of English in Indonesia, (2 to know the intensity of use of the obtained strategy types, (3 to measure the inter-correlation in the use of the obtained strategy types, and (4 to investigate the effect of proficiency level on the use of maintaining strategies. The subjects were 93 teachers applying for S2 degree in 2010/2011 at the postgraduate program of the Islamic University of Malang. They were given two sets of instrument, a Likert-scale questionnaire of English proficiency maintaining strategies and a TOEFL test. Then, a factor analysis identified nine strategy categories, including language focusing, metacognitive and affective developing, reading and writing activating, language resource utilizing, cognitive processing, culture learning, social communicating, text analyzing, and radio listening strategies. These strategy types explained 63.84% of variances of maintaining strategies and they were used at high level of intensity. Moreover, the use of the nine strategy types were found to be inter-correlated with one another. Finally, no significant effect of proficiency level on strategy use was found, indicating that teachers with different level of proficiency reported using the same strategies of maintaining their proficiency.

  7. Maintaining Discovered Frequent Itemsets: Cases for Changeable Database and Support

    Institute of Scientific and Technical Information of China (English)

    DU XiaoPing(杜孝平); TANG ShiWei(唐世渭); Akifumi Makinouchi(牧之内顕文)

    2003-01-01

    Mining frequent itemsets from large databases has played an essential role inmany data mining tasks. It is also important to maintain the discovered frequent itemsets forthese data mining tasks when the database is updated. All algorithms proposed so far for the maintenance of discovered frequent itemsets are only performed with a fixed minimum support,which is the same as that used to obtain the discovered frequent itemsets. That is, users cannot change the minimum support even if the new results are unsatisfactory to the users. In thispaper two new complementary algorithms, FMP (First Maintaining Process) and RMP (Repeated Maintaining Process), are proposed to maintain discovered frequent itemsets in the case that new transaction data are added to a transaction database. Both algorithms allow users to change theminimum support for the maintenance processes. FMP is used for the first maintaining process, andwhen the result derived from the FMP is unsatisfactory, RMP will be performed repeatedly untilsatisfactory results are obtained. The proposed algorithms re-use the previous results to cut downthe cost of maintenance. Extensive experiments have been conducted to assess the performance of the algorithms. The experimental results show that the proposed algorithms are very resultful compared with the previous mining and maintenance algorithms for maintenance of discovered frequent itemsets.

  8. Maintaining Visual Attention over Time: Effects of Object Continuity

    Directory of Open Access Journals (Sweden)

    Katsumi Watanabe

    2011-05-01

    Full Text Available Maintaining visual attention in dynamic environments is an important function of the visual system. The visual system appears to modulate attentional state to identify a target embedded in a rapid sequence of nontargets; typically, target identification gets better as the number of preceding items increases and is maintained at this increased level. We examined the temporal characteristics of the visual system that contribute to maintaining attentional state. Inserting one-second temporal gap in the sequence reset the elevated attentional state. However, the results also suggested that the attentional state was maintained as long as the sequence was interpreted as a single event (i.e., the object continuity was maintained. It has been proposed that ‘object files’ keep track of visual items and accumulate information as they move and change. It is also known that objects' features (shape and/or color affect the distribution of attention within objects. In a separate set of experiments, we examined whether the change detection of feature-location binding in moving visual objects would affect the attentional distribution within objects by using a probe-detection paradigm. The results showed that the performance of irregularity detection did not influence the attentional distribution within objects. This finding implies that attentional distribution within objects occurs independent of object continuity.

  9. Determination of the origin of urinary norandrosterone traces by gas chromatography combustion isotope ratio mass spectrometry.

    Science.gov (United States)

    Hebestreit, Moritz; Flenker, Ulrich; Fusshöller, Gregor; Geyer, Hans; Güntner, Ute; Mareck, Ute; Piper, Thomas; Thevis, Mario; Ayotte, Christiane; Schänzer, Wilhelm

    2006-09-01

    On the one hand, 19-norandrosterone (NA) is the most abundant metabolite of the synthetic anabolic steroid 19-nortestosterone and related prohormones. On the other hand, small amounts are biosynthesized by pregnant women and further evidence exists for physiological origin of this compound. The World Anti-Doping Agency (WADA) formerly introduced threshold concentrations of 2 or 5 ng of NA per ml of urine to discriminate 19-nortestosterone abuse from biosynthetic origin. Recent findings showed however, that formation of NA resulting in concentrations in the range of the threshold levels might be due to demethylation of androsterone in urine, and the WADA 2006 Prohibited List has defined NA as endogenous steroid. To elucidate the endogenous or exogenous origin of NA, (13)C/(12)C-analysis is the method of choice since synthetic 19-nortestosterone is derived from C(3)-plants by partial synthesis and shows delta(13)C(VPDB)-values of around -28 per thousand. Endogenous steroids are less depleted in (13)C due to a dietary mixture of C(3)- and C(4)-plants. An extensive cleanup based on two high performance liquid chromatography cleanup steps was applied to quality control and doping control samples, which contained NA in concentrations down to 2 ng per ml of urine. (13)C/(12)C-ratios of NA, androsterone and etiocholanolone were measured by gas chromatography/combustion/isotope ratio mass spectrometry. By comparing delta(13)C(VPDB)-values of androsterone as endogenous reference compound with NA, the origin of NA in doping control samples was determined as either endogenous or exogenous.

  10. na Perua

    Directory of Open Access Journals (Sweden)

    Jorge Carvalho

    1989-01-01

    Full Text Available Antes de se caracterizar como tentativa de ensaio ou de análise a qualquer coisa, o presente artigo tem, antes de mais nada, a pretensão de se constituir uma provocação ao debate acerca da questão do esporte na escola. A provocação parte basicamente do relato da minha experiência pessoal como Secretário da Educação do Município de Aracaju, cargo que exerci no período de 1º de janeiro de 1986 a 27 de janeiro de 1987.

  11. Fractais na arquitectura

    OpenAIRE

    2009-01-01

    Uma forma de inovar na simplicidade, em Arquitectura, é usar a geometria dos fractais. Uma técnica simples de iterativamente chegar a formas fantásticas e muito agradáveis de integrar no desenho de uma obra de arte: sejam edifícios, pontes, jardins, e outros. Vamos abordar o conceito essencial da geometria dos fractais e analisar exemplos da sua aplicação em edifícios e cidades. Para isso faz-se uma introdução ao tema pelos primórdios da geometria fractal referindo exemplos como o Co...

  12. A escola na internet

    OpenAIRE

    Albino, Ayrán Lavra

    2003-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção. O presente trabalho pretendeu analisar o uso do suporte tecnológico do ensino a distância (computador e internet) como elemento complementar do ensino presencial. Procurou-se demonstrar, na fundamentação teórica, que as tendências pedagógicas contemporâneas e as características da tecnologia digital viabilizam esta possibilidade. Operacionalizou-se essa ...

  13. Fractais na arquitectura

    OpenAIRE

    Ganhão, Susana Maria Gouveia Rosado

    2009-01-01

    Uma forma de inovar na simplicidade, em Arquitectura, é usar a geometria dos fractais. Uma técnica simples de iterativamente chegar a formas fantásticas e muito agradáveis de integrar no desenho de uma obra de arte: sejam edifícios, pontes, jardins, e outros. Vamos abordar o conceito essencial da geometria dos fractais e analisar exemplos da sua aplicação em edifícios e cidades. Para isso faz-se uma introdução ao tema pelos primórdios da geometria fractal referindo exemplos como o Co...

  14. Report from NA49

    CERN Document Server

    Gazdzicki, M; Anticic, T; Baatar, B; Barna, D; Bartke, Jerzy; Betev, L; Bialkowska, H; Billmeier, A; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Brun, R; Buncic, P; Cerny, V; Christakoglou, P; Chvala, O; Cramer, J G; Csató, P; Darmenov, N; Dimitrov, A; Dinkelaker, P; Eckardt, V; Farantatos, G; Filip, P; Flierl, D; Fodor, Z; Foka, P Y; Freund, P; Friese, V; Gál, J; Georgopoulos, G; Gladysz-Dziadus, E; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kliemant, M; Kniege9, S; Kolesnikov, V I; Kollegger, T; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Van Leeuwen, M; Lévai, Peter; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Markert, C; Mateev, M; Mayes, B W; Melkumov, G L; Meurer, C; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Pikna, M; Pinsky, L; Pühlhofer, F; Reid, J G; Renfordt, R E; Richard, A; Roland, C; Roland, G; Rybczynski, M; Rybicki, A; Sandoval, A; Sann, H; Schmitz, N; Seyboth, P; Siklér, F; Sitár, B; Skrzypczak, E; Stefanek, G; Stock, R; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Trainor, T A; Varga, D; Vassiliou, Maria; Veres, G I; Vesztergombi, G; Vranic, D; Wetzler, A; Wlodarczyk, Z; Yoo, I K; Zaranek, J; Zimányi, J

    2004-01-01

    The most recent data of NA49 on hadron production in nuclear collisions at CERN SPS energies are presented. Anomalies in the energy dependence of pion and kaon production in central Pb+Pb collisions are observed. They suggest that the onset of deconfinement is located at about 30 AGeV. Large multiplicity and transverse momentum fluctuations are measured for collisions of intermediate mass systems at 158 AGeV. The need for a new experimental programme at the CERN SPS is underlined.

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

    Science.gov (United States)

    Chew, Gina; Walczyk, Thomas

    2013-04-02

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

  16. Stable isotope labeling by amino acids in cell culture, SILAC, as a simple and accurate approach to expression proteomics

    DEFF Research Database (Denmark)

    Ong, S.E.; Blagoev, B.; Kratchmarova, I.

    2002-01-01

    . Here we describe a method, termed SILAC, for stable isotope labeling by amino acids in cell culture, for the in vivo incorporation of specific amino acids into all mammalian proteins. Mammalian cell lines are grown in media lacking a standard essential amino acid but supplemented with a non......-radioactive, isotopically labeled form of that amino acid, in this case deuterated leucine (Leu-d3). We find that growth of cells maintained in these media is no different from growth in normal media as evidenced by cell morphology, doubling time, and ability to differentiate. Complete incorporation of Leu-d3 occurred...

  17. Chemical and isotopic fingerprinting of small ungauged watershed: How far the hydrological functioning can be understood?

    Science.gov (United States)

    Petelet-Giraud, Emmanuelle; Luck, Jean-Marc; Ben Othman, Dalila; Joseph, Christian; Négrel, Philippe

    2016-05-01

    This study presents the ability of major/trace elements together with strontium isotopes to trace water origins at small scale at the outlet of a small watershed (Peyne, Hérault, France). Two small sub-basins draining distinct lithologies in their headwater (Plio-Villafranchian conglomerate versus Triassic gypsum-rich marls and dolomites) and the Miocene formations downstream are investigated. The Ca/Na vs. Mg/Na ratios and Ca/Sr vs. 87Sr/86Sr ratios allow the different facies that imprint the water signature to be identified, according to the hydrological conditions (low/high flows). Moreover, Sr isotopes evidence the two distinct Miocene facies, the sandy marls and the marine carbonates. The variation of the signature at the outlet of the basin allows identifying the main contributing compartments according to the hydrological conditions. This approach, based on a limited number of samples, highlights the potential of geochemical and isotopic tracers to define the contributing compartments to the runoff at the outlet of a basin. It thus could be considered as a potential alternative way to classical hydrological monitoring to delineate the main contributing areas during floods, especially in small ungauged river basins, where most of the devastating flash floods are recorded.

  18. Experimental identification of mechanisms controlling calcium isotopic fractionations by the vegetation.

    Science.gov (United States)

    Cobert, Florian; Schimtt, Anne-Désirée.; Bourgeade, Pascale; Stille, Peter; Chabaux, François; Badot, Pierre-Marie; Jaegler, Thomas

    2010-05-01

    This study aims to better understand the role of vegetation on the Ca cycle at the level of the critical zone of the Earth, in order to specify the mechanisms controlling the Ca absorption by plants at the rock/plant interface. To do this, we performed experiments using hydroponic plant cultures in a way that we could control the co-occuring geochemical and physiological process and determine the impact of the nutritive solution on the Ca cycle within plants. A dicotyledon and calcicole plant with rapid growth, the French bean (Phaseolus vulgaris L.), has been chosen to have access to one complete growth cycle. Several experiments have been conducted with two Ca concentrations, 6 (L) and 60 (H) ppm and two pH values (4 and 6) in the nutritive solution, for which the Ca concentration was maintained constant, so its Ca content is considered as infinite. A second experiment (non infinite L6) allowed Ca depletion in the solution through time; therefore, response effects on the Ca isotopic signatures in the plant organs and in the nutritive solution were observed. We determined Ca concentrations and isotopic ratios in the nutritive solution and in different organs (main roots, secondary roots, old and young stems, old and young leaves and fruits) at two different growth stages (10 days and 6 weeks). Preliminary results show that: (1) the roots (main and secondary) were enriched in the light isotope (40Ca) compared to the nutritive solution, and leaves were enriched in the heavy isotope (44Ca) compared to stems. These results are in accord with previously published field studies (Wigand et al., 2005; Page et al., 2008; Cenki-Tok et al., 2009; Holmden and Bélanger, 2010). Leaves and secondary roots were however enriched in the heavy isotope (44Ca) compared to bean pods, stems and main roots. These results could be related to kinetic fractionation processes occurring either during the Ca root uptake, or during the Ca transport within the plant, or physiological mechanisms

  19. Chromium isotope uptake in carbonates

    DEFF Research Database (Denmark)

    Rodler, Alexandra

    composition of contemporaneous seawater. Marine carbonates are ubiquitous throughout Earth’s rock record rendering them a particularly interesting archive for constraining past changes in ocean chemistry. This thesis includes an investigation of the fractionation behavior of Cr isotopesduring coprecipitation......Chromium (Cr) is a redox sensitive element potentially capable of tracing fine-scale fluctuations of the oxygenation of Earth’s early surface environments and seawater. The Cr isotope composition of carbonates could perhaps be used as paleo-redox proxy to elucidate changes in the geological past...... related to the rise of oxygen and the evolution of the biosphere. However, before the Cr isotopesystem can be applied to faithfully delineate paleo-environmental changes, careful assessment of the signal robustness and a thorough understanding of the Cr cycle in Earth system processes is necessary...

  20. Chromium isotope uptake in carbonates

    DEFF Research Database (Denmark)

    Rodler, Alexandra

    composition of contemporaneous seawater. Marine carbonates are ubiquitous throughout Earth’s rock record rendering them a particularly interesting archive for constraining past changes in ocean chemistry. This thesis includes an investigation of the fractionation behavior of Cr isotopesduring coprecipitation......Chromium (Cr) is a redox sensitive element potentially capable of tracing fine-scale fluctuations of the oxygenation of Earth’s early surface environments and seawater. The Cr isotope composition of carbonates could perhaps be used as paleo-redox proxy to elucidate changes in the geological past...... related to the rise of oxygen and the evolution of the biosphere. However, before the Cr isotopesystem can be applied to faithfully delineate paleo-environmental changes, careful assessment of the signal robustness and a thorough understanding of the Cr cycle in Earth system processes is necessary...

  1. Innovative scheduling to maintain clinical pharmacy services despite budget retrenchment.

    Science.gov (United States)

    Siegel, J; Schneider, P J; Moore, T D

    1984-02-01

    A process is described in which staff scheduling was adjusted to maintain pharmaceutical services while achieving a 7% cutback in personnel costs. The pharmacy department in a 1000-bed university hospital was unable to achieve the necessary cost savings through reductions in sick leave and overtime hours. The pharmacy administration developed a plan that required pharmacists to work four 10-hour shifts per week and resulted in reduced hours of service. The pharmacists objected and proposed an alternative plan in which clinical service was maintained for 16 hours on weekdays and 12 hours on weekends. Pharmacist teams worked one flexible shift per week. Pharmacists developed an innovative staffing plan that allowed them to maintain a high level of practice and acceptable working hours.

  2. Functional analysis screening for problem behavior maintained by automatic reinforcement.

    Science.gov (United States)

    Querim, Angie C; Iwata, Brian A; Roscoe, Eileen M; Schlichenmeyer, Kevin J; Ortega, Javier Virués; Hurl, Kylee E

    2013-01-01

    A common finding in previous research is that problem behavior maintained by automatic reinforcement continues to occur in the alone condition of a functional analysis (FA), whereas behavior maintained by social reinforcement typically is extinguished. Thus, the alone condition may represent an efficient screening procedure when maintenance by automatic reinforcement is suspected. We conducted a series of 5-min alone (or no-interaction) probes for 30 cases of problem behavior and compared initial predictions of maintenance or extinction to outcomes obtained in subsequent FAs. Results indicated that data from the screening procedure accurately predicted that problem behavior was maintained by automatic reinforcement in 21 of 22 cases and by social reinforcement in 7 of 8 cases. Thus, results of the screening accurately predicted the function of problem behavior (social vs. automatic reinforcement) in 28 of 30 cases.

  3. Equilateral pentagon polarization maintaining photonic crystal fibre with low nonlinearity

    Institute of Scientific and Technical Information of China (English)

    Yang Han-Rui; Li Xu-You; Hong Wei; Hao Jin-Hui

    2012-01-01

    A new pentagon polarization maintaining photonic crystal fibre with low nonlinearity is introduced. The full vector finite element method was used to investigate the distribution and the effective area of modal field,the nonlinear properties,the effective indices of two orthogonal polarization modes and the birefringence of the new PM-PCF effectively.It is found that the birefringence of the new polarization maintaining photonic crystal fibre can easily achieve the order of 10-4,and it can obtain higher birefringence,larger effectively mode-field area and lower nonlinearity than traditional hexagonal polarization maintaining photonic crystal fibre with the same hole pitch,same hole diameter,and same ring number.It is important for sensing and communication applications,especially has potential application for fibre optical gyroscope.

  4. Compound specific isotope analysis of organophosphorus pesticides.

    Science.gov (United States)

    Wu, Langping; Yao, Jun; Trebse, Polonca; Zhang, Ning; Richnow, Hans H

    2014-09-01

    Compound-specific isotope analysis (CSIA) has been established as a tool to study the environmental fate of a wide range of contaminants. In this study, CSIA was developed to analyse the stable carbon isotope signatures of the widely used organophosphorus pesticides: dichlorvos, omethoate and dimethoate. The linearity of the GC-C-IRMS system was tested for target pesticides and led to an acceptable isotope composition within the uncertainty of the instrument. In order to assess the accuracy of the developed method, the effect of the evaporation procedure on measured carbon isotope composition (δ(13)C) values was studied and showed that concentration by evaporation of solvents had no significant isotope effect. The CSIA was then applied to investigate isotope fractionation of the hydrolysis and photolysis of selected pesticides. The carbon isotope fractionation of tested pesticides was quantified by the Rayleigh model, which revealed a bulk enrichment factor (ε) of -0.2±0.1‰ for hydrolysis of dichlorvos, -1.0±0.1‰ and -3.7±1.1‰ for hydrolysis and photolysis of dimethoate respectively. This study is a first step towards the application of CSIA to trace the transport and degradation of organophosphorus pesticides in the environment.

  5. Stable isotopic characterisation of francolite formation

    Science.gov (United States)

    McArthur, J. M.; Benmore, R. A.; Coleman, M. L.; Soldi, C.; Yeh, H.-W.; O'Brien, G. W.

    1986-02-01

    Stable isotopic data are presented for 112 samples of francolite from 18 separate phosphate deposits. Values of δ 13C and δ 34S in most offshore deposits suggest formation within oxic or suboxic environments either by carbonate replacement or direct precipitation of francolite from water of normal marine compositions. The exceptions are concretionary francolite from Namibia, which has an isotopic composition in keeping with its formation within organic-rich sediments, and that from offshore Morocco, which has an isotopic signature of the anoxic/suboxic interface. Onshore deposits from Jordan, Mexico, South Africa and, possibly, the Permian Phosphoria Formation in the western U.S.A., are substantially depleted in 18O: they appear to be too altered for deductions to be made about their environments of formation. In other onshore deposits which are unaltered, or minimally altered, the isotopic composition suggests that some formed within sulphate-reducing sediments (Sedhura, Morocco) whilst francolite from the Georgina Basin of Australia formed at the oxic/anoxic boundary, where oxidation of biogenic H 2S decreases the δ 34S of pore water. In general, pelletal samples show non-oxic isotopic signatures, whilst non-pelletal samples show oxic isotopic signatures, but samples from Namibia, Peru (Ica Plateau) and the Californian and Moroccan margins are exceptions to this rule. Morphology may therefore be a misleading indicator of francolite genesis as no definitive relation exists between phosphorite type and isotopic signature.

  6. The isotope effect: Prediction, discussion, and discovery

    CERN Document Server

    Kragh, Helge

    2011-01-01

    The precise position of a spectral line emitted by an atomic system depends on the mass of the atomic nucleus and is therefore different for isotopes belonging to the same element. The possible presence of an isotope effect followed from Bohr's atomic theory of 1913, but it took several years before it was confirmed experimentally. Its early history involves the childhood not only of the quantum atom, but also of the concept of isotopy. Bohr's prediction of the isotope effect was apparently at odds with early attempts to distinguish between isotopes by means of their optical spectra. However, in 1920 the effect was discovered in HCl molecules, which gave rise to a fruitful development in molecular spectroscopy. The first detection of an atomic isotope effect was no less important, as it was by this means that the heavy hydrogen isotope deuterium was discovered in 1932. The early development of isotope spectroscopy illustrates the complex relationship between theory and experiment, and is also instructive with...

  7. Si isotope homogeneity of the solar nebula

    Energy Technology Data Exchange (ETDEWEB)

    Pringle, Emily A.; Savage, Paul S.; Moynier, Frédéric [Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130 (United States); Jackson, Matthew G. [Department of Earth Science, University of California, Santa Barbara, CA 93109 (United States); Barrat, Jean-Alix, E-mail: eapringle@wustl.edu, E-mail: savage@levee.wustl.edu, E-mail: pringle@ipgp.fr, E-mail: moynier@ipgp.fr, E-mail: jackson@geol.ucsb.edu, E-mail: Jean-Alix.Barrat@univ-brest.fr [Université Européenne de Bretagne, Université de Brest, CNRS UMR 6538 (Domaines Océaniques), I.U.E.M., Place Nicolas Copernic, F-29280 Plouzané Cedex (France)

    2013-12-20

    The presence or absence of variations in the mass-independent abundances of Si isotopes in bulk meteorites provides important clues concerning the evolution of the early solar system. No Si isotopic anomalies have been found within the level of analytical precision of 15 ppm in {sup 29}Si/{sup 28}Si across a wide range of inner solar system materials, including terrestrial basalts, chondrites, and achondrites. A possible exception is the angrites, which may exhibit small excesses of {sup 29}Si. However, the general absence of anomalies suggests that primitive meteorites and differentiated planetesimals formed in a reservoir that was isotopically homogenous with respect to Si. Furthermore, the lack of resolvable anomalies in the calcium-aluminum-rich inclusion measured here suggests that any nucleosynthetic anomalies in Si isotopes were erased through mixing in the solar nebula prior to the formation of refractory solids. The homogeneity exhibited by Si isotopes may have implications for the distribution of Mg isotopes in the solar nebula. Based on supernova nucleosynthetic yield calculations, the expected magnitude of heavy-isotope overabundance is larger for Si than for Mg, suggesting that any potential Mg heterogeneity, if present, exists below the 15 ppm level.

  8. Validation Effectiveness of Develop Maintainability Allocation on Aircraft Mechanical Components

    Directory of Open Access Journals (Sweden)

    Wan Husain W.M.S.

    2016-01-01

    Full Text Available Maintainability Allocation is a process to identify the allowable maximum task time for each individual component. Consequently, this provides clear pictures to the designers to design and identify potential design improvement within allowable maintenance allocation time limits. During the design process elements such as missteps or misapplications most commonly occur. Here, the authors propose having the maximum target for each individual maintainability component. The main objective of this paper is to present the validation process of developed Maintainability Allocation to potentially eliminate previous problems. The process of validation begins with analysed all the data collected from Service Difficulty Reports (SDR for selected aircraft. This is to understand the problems from existing aircraft before a new design is proposed through the process of Maintainability Allocation prediction. The validation processes have discovered the importance of utilising historical information such as feedback information. The second area is looking at the element of quantifying the data collected from aircraft feedback information which contains various types of information that could be used for future improvement. Validation process shows that feedback information has helped to identify the critical and sensitive components that need more attention for further improvement. The study shows that the aircraft maintenance related feedback information systems analyses were very useful for deciding maintainability effectiveness; these include planning, organising maintenance and design improvement. There is no doubt that feedback information has the ability to contribute an important role in design activities. The results also show that maintainability is an important measure that can be used as a guideline for managing efforts made for the improvement of aircraft components.

  9. Maintainability design criteria for packaging of spacecraft replaceable electronic equipment.

    Science.gov (United States)

    Kappler, J. R.; Folsom, A. B.

    1972-01-01

    Maintainability must be designed into long-duration spacecraft and equipment to provide the required high probability of mission success with the least cost and weight. The ability to perform repairs quickly and easily in a space environment can be achieved by imposing specific maintainability design criteria on spacecraft equipment design and installation. A study was funded to investigate and define design criteria for electronic equipment that would permit rapid removal and replacement in a space environment. The results of the study are discussed together with subsequent simulated zero-g demonstration tests of a mockup with new concepts for packaging.

  10. Maintaining realism in auditory length-perception experiments

    DEFF Research Database (Denmark)

    Kirkwood, Brent Christopher

    2005-01-01

    Humans are capable of hearing the lengths of wooden rods dropped onto hard floors. In an attempt to understand the influence of the stimulus presentation method for testing this kind of everyday listening task, listener performance was compared for three presentation methods in an auditory length......-estimation experiment. A comparison of the length-estimation accuracy for the three presentation methods indicates that the choice of presentation method is important for maintaining realism and for maintaining the acoustic cues utilized by listeners in perceiving length....

  11. Maintainability design criteria for packaging of spacecraft replaceable electronic equipment.

    Science.gov (United States)

    Kappler, J. R.; Folsom, A. B.

    1972-01-01

    Maintainability must be designed into long-duration spacecraft and equipment to provide the required high probability of mission success with the least cost and weight. The ability to perform repairs quickly and easily in a space environment can be achieved by imposing specific maintainability design criteria on spacecraft equipment design and installation. A study was funded to investigate and define design criteria for electronic equipment that would permit rapid removal and replacement in a space environment. The results of the study are discussed together with subsequent simulated zero-g demonstration tests of a mockup with new concepts for packaging.

  12. Maintaining realism in auditory length-perception experiments

    DEFF Research Database (Denmark)

    Kirkwood, Brent Christopher

    2005-01-01

    Humans are capable of hearing the lengths of wooden rods dropped onto hard floors. In an attempt to understand the influence of the stimulus presentation method for testing this kind of everyday listening task, listener performance was compared for three presentation methods in an auditory length......-estimation experiment. A comparison of the length-estimation accuracy for the three presentation methods indicates that the choice of presentation method is important for maintaining realism and for maintaining the acoustic cues utilized by listeners in perceiving length....

  13. Sharing the sandbox: Evolutionary mechanisms that maintain bacterial cooperation.

    Science.gov (United States)

    Bruger, Eric; Waters, Christopher

    2015-01-01

    Microbes are now known to participate in an extensive repertoire of cooperative behaviors such as biofilm formation, production of extracellular public-goods, group motility, and higher-ordered multicellular structures. A fundamental question is how these cooperative tasks are maintained in the face of non-cooperating defector cells. Recently, a number of molecular mechanisms including facultative participation, spatial sorting, and policing have been discovered to stabilize cooperation. Often these different mechanisms work in concert to reinforce cooperation. In this review, we describe bacterial cooperation and the current understanding of the molecular mechanisms that maintain it.

  14. Renal β-intercalated cells maintain body fluid and electrolyte balance.

    Science.gov (United States)

    Gueutin, Victor; Vallet, Marion; Jayat, Maximilien; Peti-Peterdi, Janos; Cornière, Nicolas; Leviel, Françoise; Sohet, Fabien; Wagner, Carsten A; Eladari, Dominique; Chambrey, Régine

    2013-10-01

    Inactivation of the B1 proton pump subunit (ATP6V1B1) in intercalated cells (ICs) leads to type I distal renal tubular acidosis (dRTA), a disease associated with salt- and potassium-losing nephropathy. Here we show that mice deficient in ATP6V1B1 (Atp6v1b1-/- mice) displayed renal loss of NaCl, K+, and water, causing hypovolemia, hypokalemia, and polyuria. We demonstrated that NaCl loss originated from the cortical collecting duct, where activity of both the epithelial sodium channel (ENaC) and the pendrin/Na(+)-driven chloride/bicarbonate exchanger (pendrin/NDCBE) transport system was impaired. ENaC was appropriately increased in the medullary collecting duct, suggesting a localized inhibition in the cortex. We detected high urinary prostaglandin E2 (PGE2) and ATP levels in Atp6v1b1-/- mice. Inhibition of PGE2 synthesis in vivo restored ENaC protein levels specifically in the cortex. It also normalized protein levels of the large conductance calcium-activated potassium channel and the water channel aquaporin 2, and improved polyuria and hypokalemia in mutant mice. Furthermore, pharmacological inactivation of the proton pump in β-ICs induced release of PGE2 through activation of calcium-coupled purinergic receptors. In the present study, we identified ATP-triggered PGE2 paracrine signaling originating from β-ICs as a mechanism in the development of the hydroelectrolytic imbalance associated with dRTA. Our data indicate that in addition to principal cells, ICs are also critical in maintaining sodium balance and, hence, normal vascular volume and blood pressure.

  15. Thermal Water's Isotope Geochemistry Study of Evros Area, NE Greece

    Science.gov (United States)

    Elissavet, Dotsika; Paraskevi, Chantzi

    2016-10-01

    Thermal waters from Evros area were collected and subjected to chemical and isotopic analysis in order to understand all the physicochemical mechanisms (mixing, dilution, precipitating) that contribute to the shallow and deep geothermal water tables and determine the origin of these fluids as well as their mineralization. Physicochemical characteristics EC, T°C, pH was determined at the field. The ionic concentrations of samples indicate solutions with high salinity. Two chemical water types were arisen: Na-SO4 concerning low temperatures and shallow aquifers and Na- Cl concerning high temperatures and deeper geothermal circulation. The ratio Br/Cl definitely considered marine origin indicator is the same as the sea confirming the involvement of the seawater in the geothermal system. The marine component and water-rock interaction process under high temperatures seem to contribute to the mineralization of thermal waters. Moreover, water-rock interaction process is also responsible for the alternation of δ18O values. Geothermometers concluded to a middle enthalpy geothermal field.

  16. Comprometimento pulmonar na leptospirose

    Directory of Open Access Journals (Sweden)

    Jorge Eduardo Manhães de Carvalho

    1992-03-01

    Full Text Available Em 23 pacientes com leptospirose apresentando comprometimento pulmonar, internados no Hospital Universitário Antônio Pedro da XJFF, Niterói, hemoptise e hemoptóicos foram observados em 21,7% e 30,4%, respectivajnente. Gasometria arterial revelou hipoxemia e hipocapnia na maioria dos casos. Radiografia de tórax em 15 pacientes mostrou comprometimento alveolar em 60%, comprometimento intersticial-reticular em 6%, padrão misto (alveolar e intersticial em20%e ausência de alterações radiológicas em 14%. A necrópsiade 13 pacientes mostrou edema, congestão e hemorragia nos pulmões em 100% dos casos. A hemorragia foi focal em 46% e difusa em 54% dos casos. Houve formação de membrana hialina em 30% e trombos de fibrina em 46% dos pulmões estudados, o que estabelece o diagnóstico da coagulação intravascular disseminada e a ocorrência da síndrome de angústia respiratória na leptospirose.

  17. Strontium isotope geochemistry of alluvial groundwater: a tracer for groundwater resources characterisation

    Directory of Open Access Journals (Sweden)

    P. Négrel

    2004-01-01

    Full Text Available This study presents strontium isotope and major ion data of shallow groundwater and river water from the Ile du Chambon catchment, located on the Allier river in the Massif Central (France. There are large variations in the major-element contents in the surface- and groundwater. Plotting of Na vs. Cl contents and Ca, Mg, NO3, K, SO4, HCO3, Sr concentrations reflect water–rock interaction (carbonate dissolution for Ca, Mg, HCO3 and Sr because the bedrock contains marly limestones, agricultural input (farming and fertilising and sewage effluents (for NO3, K, SO4, although some water samples are unpolluted. Sr contents and isotope ratios (87Sr/86Sr vary from 0.70892 to 0.71180 along the hydrological cycle in the groundwater agree with previous work on groundwater in alluvial aquifers in the Loire catchment. The data plot along three directions in a 87Sr/86Sr v. 1/Sr diagram as a result of mixing, involving at least three geochemical signatures–Allier river water, and two distinct signatures that might be related to different water-rock interactions in the catchment. Mixing proportions are calculated and discussed. The alluvial aquifer of the Ile du Chambon catchment is considered, within the Sr isotope systematic, in a larger scheme that includes several alluvial aquifers of the Loire Allier catchment. Keywords: : Loire river, major and trace elements, Sr isotopic ratio, alluvial aquifer, hydrology

  18. Measuring oxygen isotopes beyond the neutron dripline: Two-neutron emission and radioactivity

    Science.gov (United States)

    Kohley, Zach

    2013-10-01

    The availability of rare isotope beams has made it possible to extend nuclear structure measurements to nuclei far away from stability. Drastic changes in the structure, properties, and available decay-modes of these exotic isotopes have been observed in comparison to their stable counterparts. The oxygen isotopic chain has been particularly interesting with observations of new shell closures at N = 14 and N = 16. The MoNA-LISA/Sweeper setup at the National Superconducting Cyclotron Laboratory at Michigan State University has allowed for studies of the oxygen isotopes to be extended beyond the neutron dripline. Recently, the 26O ground state was observed for the first time and shown to be unbound by less than 200 keV. The low energy ground state of the two-neutron unbound 26O opened the possibility for the discovery of two-neutron radioactivity. A new technique was developed to measure the lifetimes of neutron unbound nuclei in the picosecond range. This technique was applied to the 26O decay and a half-life of 4.5-1. 5 + 1 . 1 (stat.) +/-3 (sys.) ps was extracted. This corresponds to 26O having a finite lifetime at an 82% confidence level and, thus, suggests the possibility of two-neutron radioactivity. Supported by the National Science Foundation, under Grant No. PHY-1102511.

  19. Elemental and isotopic fingerprint of Argentinean wheat. Matching soil, water, and crop composition to differentiate provenance.

    Science.gov (United States)

    Podio, Natalia S; Baroni, María V; Badini, Raúl G; Inga, Marcela; Ostera, Héctor A; Cagnoni, Mariana; Gautier, Eduardo A; García, Pilar Peral; Hoogewerff, Jurian; Wunderlin, Daniel A

    2013-04-24

    The aim of this study was to investigate if elemental and isotopic signatures of Argentinean wheat can be used to develop a reliable fingerprint to assess its geographical provenance. For this pilot study we used wheat cultivated at three different regions (Buenos Aires, Córdoba, and Entre Ríos), together with matching soil and water. Elemental composition was determined by ICP-MS. δ(13)C and δ(15)N were measured by isotopic ratio mass spectrometry, while (87)Sr/(86)Sr ratio was determined using thermal ionization mass spectrometry. Wheat samples from three sampling sites were differentiated by the combination of 11 key variables (K/Rb, Ca/Sr, Ba, (87)Sr/(86)Sr, Co, Mo, Zn, Mn, Eu, δ(13)C, and Na), demonstrating differences among the three studied regions. The application of generalized Procrustes analysis showed 99.2% consensus between cultivation soil, irrigation water, and wheat samples, in addition to clear differences between studied areas. Furthermore, canonical correlation analysis showed significant correlation between the elemental and isotopic profiles of wheat and those corresponding to both soil and water (r(2) = 0.97, p wheat samples using different statistical methods, showing that wheat elemental and isotopic compositions are mainly related to soil and irrigation water characteristics of the site of growth.

  20. Laser na medicina: avanços na Oftalmologia

    OpenAIRE

    João Alberto Holanda de Freitas

    2007-01-01

    Entre os grandes avanços tecnológicos dos últimos anos, o laser sem dúvida ocupa lugar de destaque. Desde a construção do primeiro aparelho a laser em 1959, novas aplicações surgem continuadamente. O laser está presente de maneira marcante na pesquisa básica, na indústria e na medicina.

  1. Production and relevance of cosmogenic radionuclides in NaI(Tl) crystals

    Energy Technology Data Exchange (ETDEWEB)

    Amaré, J.; Cebrián, S.; Cuesta, C.; García, E.; Ginestra, C.; Martínez, M.; Oliván, M. A.; Ortigoza, Y.; Ortiz de Solórzano, A.; Pobes, C.; Puimedón, J.; Sarsa, M. L.; Villar, J. A.; Villar, P. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain); Laboratorio Subterráneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estación, Huesca (Spain)

    2015-08-17

    The cosmogenic production of long-lived radioactive isotopes in materials is an hazard for experiments demanding ultra-low background conditions. Although NaI(Tl) scintillators have been used in this context for a long time, very few activation data were available. We present results from two 12.5 kg NaI(Tl) detectors, developed within the ANAIS project and installed at the Canfranc Underground Laboratory. The prompt data taking starting made possible a reliable quantification of production of some I, Te and Na isotopes with half-lives larger than ten days. Tnitial activities underground were measured and then production rates at sea level were estimated following the history of detectors; a comparison of these rates with calculations using typical cosmic neutron flux at sea level and a selected description of excitation functions was also carried out. After including the contribution from the identified cosmogenic products in the detector background model, we found that the presence of {sup 3}H in the crystal bulk would help to fit much better our background model and experimental data. We have analyzed the cosmogenic production of {sup 3}H in NaI, and although precise quantification has not been attempted, we can conclude that it could imply a very relevant contribution to the total background below 15 ke in NaI detectors.

  2. Na(+) regulation by combined nitrogen in Azolla pinnata-Anabaena azollae symbiotic association during salt toxicity.

    Science.gov (United States)

    Singh, Satya S; Singh, Santosh K; Mishra, Arun K

    2008-01-01

    To study the regulation of Na(+) ion by combined-N sources in Azolla pinnata-Anabaena azollae, Na(+) influx, intracellular Na(+) and Na(+) efflux were investigated in the presence of different N-sources (N(2), NH(4)(+), NO(3)(-) and urea) and various NaCl concentrations. Sodium influx by Azolla pinnata fronds was minimum in the presence of NO(3)(-). Almost identical levels of intracellular sodium, although less than N(2) and NH(4)(+) incubated fronds were observed in the presence of NO(3)(-) and urea. Efflux of sodium was minimum in urea and NO(3)(-) grown fronds. A low residual sodium was observed in the fronds incubated in NO(3)(-) and urea supplemented media. Results suggest that nitrate and urea curtailed the entry of sodium, reduced salt toxicity maximally by maintaining the minimum level of sodium and also conserved energy due to slow influx and efflux of Na(+) within the fronds during salt shock and the process of adaptation.

  3. Beneficial uses and production of isotopes

    CERN Document Server

    2001-01-01

    Isotopes, radioactive and stable, are used worldwide in various applications related to medical diagnosis or care, industry and scientific research. More than fifty countries have isotope production or separation facilities operated for domestic supply, and sometimes for international markets. This publication provides up-to-date information on the current status of, and trends in, isotope uses and production. It also presents key issues, conclusions and recommendations, which will be of interest to policy makers in governmental bodies, scientists and industrial actors in the field.

  4. Hafnium isotope stratigraphy of ferromanganese crusts

    Science.gov (United States)

    Lee, D.-C.; Halliday, A.N.; Hein, J.R.; Burton, K.W.; Christensen, J.N.; Gunther, D.

    1999-01-01

    A Cenozoic record of hafnium isotopic compositions of central Pacific deep water has been obtained from two ferromanganese crusts. The crusts are separated by more than 3000 kilometers but display similar secular variations. Significant fluctuations in hafnium isotopic composition occurred in the Eocene and Oligocene, possibly related to direct advection from the Indian and Atlantic oceans. Hafnium isotopic compositions have remained approximately uniform for the past 20 million years, probably reflecting increased isolation of the central Pacific. The mechanisms responsible for the increase in 87Sr/86Sr in seawater through the Cenozoic apparently had no effect on central Pacific deep-water hafnium.

  5. Isotopic Fractionation of Selenium Oxyanions in Wetlands

    Science.gov (United States)

    Clark, S. K.; Johnson, T. M.

    2004-05-01

    As oxic surface waters pass through aquatic macrophytes and over anoxic sediments in wetlands and lakes, the dissolved Se load often decreases; and, Se isotope ratio measurements can provide information about the mechanisms involved. Previous work on microbially induced isotopic fractionation of Se oxyanions under nearly natural conditions using wetland sediments shows consistent Se isotopic shifts during reduction of Se(VI) and Se(IV) to insoluble Se(0). However, previous isotopic studies of total dissolved selenium in wetlands found little to no isotopic shift as dissolved selenium concentrations decreased. This suggests that plant/algal uptake, followed by deposition and degradation, is the primary route of Se transfer into sediments. However, it is possible that the effective isotopic fractionation between Se in the surface water and Se deposited into sediments is somehow much less than the fractionation induced by the reduction reaction, or that cycling of organically bound Se is involved. In this study, we report Se isotope data for Se(VI), Se(IV) and total dissolved Se, Se(T), in surface waters from three wetland/lake sites: Sweitzer Lake, CO; 33-Mile Reservoir, WY; and, a small pond adjacent to Benton Lake, MT. We isolated Se(IV) via hydride generation, and Se(VI) via ion exchange. Se(T), including any organic components, was also analyzed. Isotope analysis was performed on an Isoprobe MC-ICPMS, using a method modified from that of Rouxel et al. (2002). We used the 82Se + 74Se double spike approach, and spiked samples before species separation. Our results for all three locations indicate similar trends in concentration changes and isotopic shifts between the inflow and outflow waters. Se(T) concentrations decrease by 45-70%, and Se(VI) concentrations decrease by 60-90%, whereas Se(IV) concentrations increase by 60-150%. Concomitant 80Se/76Se shifts are +0.5-0.8‰ for Se(T); -0.1-0.5‰ for Se(VI); and +0.4-6.5‰ for Se(IV). These data provide greater

  6. The Facility for Rare Isotope Beams

    Directory of Open Access Journals (Sweden)

    Wrede C.

    2015-01-01

    Full Text Available The Facility for Rare Isotope Beams (FRIB is a United States Department of Energy user facility currently under construction on the campus of Michigan State University. Based on a 400 kW, 200 MeV/u heavy-ion driver linac, FRIB will deliver high-quality fast, thermalized, and re-accelerated beams of rare isotopes with unprecedented intensities to a variety of experimental areas and equipment. New science opportunities at the frontiers of nuclear structure, nuclear astrophysics, fundamental symmetries, and societal applications will be enabled by this future world-leading rare-isotope beam facility.

  7. The Facility for Rare Isotope Beams

    Science.gov (United States)

    Wrede, C.

    2015-05-01

    The Facility for Rare Isotope Beams (FRIB) is a United States Department of Energy user facility currently under construction on the campus of Michigan State University. Based on a 400 kW, 200 MeV/u heavy-ion driver linac, FRIB will deliver high-quality fast, thermalized, and re-accelerated beams of rare isotopes with unprecedented intensities to a variety of experimental areas and equipment. New science opportunities at the frontiers of nuclear structure, nuclear astrophysics, fundamental symmetries, and societal applications will be enabled by this future world-leading rare-isotope beam facility.

  8. Equilibrium Fe isotope fractionation between inorganic aqueous Fe(III) and the siderophore complex, Fe(III)-desferrioxamine B

    DEFF Research Database (Denmark)

    Dideriksen, Knud; Baker, Joel A.; Stipp, Susan Louise Svane

    2008-01-01

    In oxic oceans, most of the dissolved iron (Fe) exists as complexes with siderophore-like, strongly coordinating organic ligands. Thus, the isotope composition of the little amount of free inorganic Fe that is available for precipitation and preservation in the geological record may largely...... differently complexed Fe(III) pools were separated by addition of Na2CO3, which led to immediate precipitation of the inorganic Fe without causing significant dissociation of Fe-desferrioxamine complexes. Experiments using enriched 57Fe tracer showed that isotopic equilibration between the 57Fe......(III)-bearing environments, such as soils and rivers, and may, for example, largely control the Fe isotope composition of marine Fe–Mn crusts....

  9. Isotope effects of hafnium in solvent extraction using crown ethers

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Toshiyuki; Moriyama, Hirotake [Research Reactor Institute, Kyoto University, Osaka (Japan); Hirata, Takafumi [Laboratory for Planetary Sciences, Tokyo Institute of Technology, Tokyo (Japan); Nishizawa, Kazushige [Department of Nuclear Engineering, Graduate School of Engineering, Osaka University, Osaka (Japan)

    2001-06-01

    Hafnium isotopes were fractionated in a liquid-liquid extraction system by using seven types of crown ethers, tributyl phosphate, or {omicron}-diethoxybenzene. The largest isotope effect was observed in the isotope pair of {sup 177}Hf-{sup 179}Hf with dibenzo-24-crown-8; the isotope enrichment factor was observed to be 0.0129{+-}0.0032. (author)

  10. Influence of liquid structure on diffusive isotope separation in molten silicates and aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, J.M.; DePaolo, D.J.; Ryerson, F.J.; Peterson, B.

    2011-03-01

    Molecular diffusion in natural volcanic liquids discriminates between isotopes of major ions (e.g., Fe, Mg, Ca, and Li). Although isotope separation by diffusion is expected on theoretical grounds, the dependence on mass is highly variable for different elements and in different media. Silicate liquid diffusion experiments using simple liquid compositions were carried out to further probe the compositional dependence of diffusive isotopic discrimination and its relationship to liquid structure. Two diffusion couples consisting of the mineral constituents anorthite (CaAl{sub 2}Si{sub 2}O{sub 8}; denoted AN), albite (NaAlSi{sub 3}O{sub 8}; denoted AB), and diopside (CaMgSi{sub 2}O{sub 6}; denoted DI) were held at 1450°C for 2 h and then quenched to ambient pressure and temperature. Major-element as well as Ca and Mg isotope profiles were measured on the recovered quenched glasses. In both experiments, Ca diffuses rapidly with respect to Si. In the AB–AN experiment, D{sub Ca}/D{sub Si} ~ 20 and the efficiency of isotope separation for Ca is much greater than in natural liquid experiments where D{sub Ca}/D{sub Si} ~ 1. In the AB–DI experiment, D{sub Ca}/D{sub Si} ~ 6 and the efficiency of isotope separation is between that of the natural liquid experiments and the AB–AN experiment. In the AB–DI experiment, D{sub Mg}/D{sub Si} ~ 1 and the efficiency of isotope separation for Mg is smaller than it is for Ca yet similar to that observed for Mg in natural liquids. The results from the experiments reported here, in combination with results from natural volcanic liquids, show clearly that the efficiency of diffusive separation of Ca isotopes is systematically related to the solvent-normalized diffusivity—the ratio of the diffusivity of the cation (D{sub Ca}) to the diffusivity of silicon (D{sub Si}). The results on Ca isotopes are consistent with available data on Fe, Li, and Mg isotopes in silicate liquids, when considered in terms of the parameter D{sub cation

  11. Isotope effects on desorption kinetics of hydrogen isotopes implanted into stainless steel by glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, M.; Kondo, M.; Noda, N. [Hydrogen Isotope Research Center, University of Toyama, Gofuku, Toyama (Japan); Tanaka, M.; Nishimura, K. [National Institute for Fusion Science, Toki-shi, Gifu (Japan)

    2015-03-15

    In a fusion device the control of fuel particles implies to know the desorption rate of hydrogen isotopes by the plasma-facing materials. In this paper desorption kinetics of hydrogen isotopes implanted into type 316L stainless steel by glow discharge have been studied by experiment and numerical calculation. The temperature of a maximum desorption rate depends on glow discharge time and heating rate. Desorption spectra observed under various experimental conditions have been successfully reproduced by numerical simulations that are based on a diffusion-limited process. It is suggested, therefore, that desorption rate of a hydrogen isotope implanted into the stainless steel is limited by a diffusion process of hydrogen isotope atoms in bulk. Furthermore, small isotope effects were observed for the diffusion process of hydrogen isotope atoms. (authors)

  12. Environmental geochemistry of calcium isotopes: Applications of a new stable isotope approach

    Institute of Scientific and Technical Information of China (English)

    LIU Zhanmin; LIU Congqiang; HAN Guilin; WANG Zhongliang; XUE Zichen; SONG Zhaoliang; YANG Cheng

    2006-01-01

    This paper summarizes isotope fractionation mechanism, analytical method and applications in environmental geochemistry of calcium isotopes. Calcium isotopic composition can be used to constrain material sources and study geological and environmental processes as the isotopic composition of calcium (δ 44Ca) and fractionation processes depend on geochemical circumstances in nature. Recently, thanks to current advances in analytical technology of calcium isotopes, calcium isotopes are broadly used in biological and geochemical studies, such as the mechanism of plants imbibing nutrients through their roots, calcium transport in the environmental ecosystem, calcium cycle in oceans and paleo-oceans and paleo-climate. The elementary data show that δ44Ca values vary from -2.88‰ to 0.92‰ in natural samples.

  13. Newtonian kinetic isotope effects. Observation, prediction, and origin of heavy-atom dynamic isotope effects.

    Science.gov (United States)

    Kelly, Kelmara K; Hirschi, Jennifer S; Singleton, Daniel A

    2009-06-24

    Intramolecular (13)C kinetic isotope effects were determined for the dimerization of cyclopentadiene. Substantial isotope effects were observed in three positions, despite the C(2) symmetry of the cycloaddition transition state and the absence of dynamical bottlenecks after this transition state. The observed isotope effects were predicted well from trajectory studies by extrapolating the outcomes of trajectories incorporating superheavy isotopes of carbon, ranging from (20)C to (140)C. Trajectory studies suggest that the isotope effects are unrelated to zero-point energy or the geometrical and momentum properties of the transition state. However, steepest-descent paths in mass-weighted coordinates correctly predict the direction of the isotope effects, supporting a novel origin in Newton's second law of motion.

  14. Identifying the origin and geochemical evolution of groundwater using hydrochemistry and stable isotopes in Subei Lake Basin, Ordos energy base, Northwestern China

    Directory of Open Access Journals (Sweden)

    F. Liu

    2014-05-01

    Full Text Available A hydrochemical and isotopic study was conducted in Subei Lake Basin, northwestern China, to identify the origin and geochemical evolution of groundwater. Water samples were collected, major ions and stable isotopes (δ18O, δ D were analyzed. In terms of hydrogeological conditions in study area, groundwater can be classified into three types: the Quaternary groundwater, the shallow Cretaceous groundwater, the deep Cretaceous groundwater. Piper diagram and correlation analysis were used to reveal the hydrochemical characteristics of water resources. The dominant water type of lake water was Na-Cl type, which was controlled by strong evaporation and recharge from overland flow and groundwater; the predominant hydrochemical types for groundwater were Ca-HCO3, Na-HCO3, and mixed Ca · Na · Mg-HCO3 types, the groundwater chemistry is mainly controlled by dissolution/precipitation of anhydrite, gypsum, halite and calcite. The dedolomitization and cation exchange are also important factors. Rock weathering is confirmed to play a leading role in the mechanisms responsible for the chemical compositions of groundwater. The stable isotopic values of oxygen and hydrogen in groundwater are close to the local meteoric water line, showing that groundwater is of meteoric origin. The deep Cretaceous groundwater is depleted in heavy isotopes, compared to shallow Cretaceous groundwater. The hydrogen and oxygen isotopes signatures in deep Cretaceous groundwater may show a paleorecharge effect that the deep Cretaceous groundwater was recharged during a geologic period when the climate was wetter and colder than today. Due to strong evaporation effect and dry climatic conditions, heavy isotopes are more enriched in lake water than groundwater. The hydrochemical and isotopic information of utmost importance has been provided to decision-makers by the present study so that a sustainable water resources management policy could be designed for the Ordos energy base.

  15. Tissue turnover rates and isotopic trophic discrimination factors in the endothermic teleost, pacific bluefin tuna (Thunnus orientalis.

    Directory of Open Access Journals (Sweden)

    Daniel J Madigan

    Full Text Available Stable isotope analysis (SIA of highly migratory marine pelagic animals can improve understanding of their migratory patterns and trophic ecology. However, accurate interpretation of isotopic analyses relies on knowledge of isotope turnover rates and tissue-diet isotope discrimination factors. Laboratory-derived turnover rates and discrimination factors have been difficult to obtain due to the challenges of maintaining these species in captivity. We conducted a study to determine tissue- (white muscle and liver and isotope- (nitrogen and carbon specific turnover rates and trophic discrimination factors (TDFs using archived tissues from captive Pacific bluefin tuna (PBFT, Thunnus orientalis, 1-2914 days after a diet shift in captivity. Half-life values for (15N turnover in white muscle and liver were 167 and 86 days, and for (13C were 255 and 162 days, respectively. TDFs for white muscle and liver were 1.9 and 1.1‰ for δ(15N and 1.8 and 1.2‰ for δ(13C, respectively. Our results demonstrate that turnover of (15N and (13C in bluefin tuna tissues is well described by a single compartment first-order kinetics model. We report variability in turnover rates between tissue types and their isotope dynamics, and hypothesize that metabolic processes play a large role in turnover of nitrogen and carbon in PBFT white muscle and liver tissues. (15N in white muscle tissue showed the most predictable change with diet over time, suggesting that white muscle δ(15N data may provide the most reliable inferences for diet and migration studies using stable isotopes in wild fish. These results allow more accurate interpretation of field data and dramatically improve our ability to use stable isotope data from wild tunas to better understand their migration patterns and trophic ecology.

  16. Fractionation of Cu and Zn isotopes during adsorption onto amorphous Fe(III) oxyhydroxide: Experimental mixing of acid rock drainage and ambient river water

    Science.gov (United States)

    Balistrieri, Laurie S.; Borrok, David M.; Wanty, Richard B.; Ridley, W. Ian

    2008-01-01

    Fractionation of Cu and Zn isotopes during adsorption onto amorphous ferric oxyhydroxide is examined in experimental mixtures of metal-rich acid rock drainage and relatively pure river water and during batch adsorption experiments using synthetic ferrihydrite. A diverse set of Cu- and Zn-bearing solutions was examined, including natural waters, complex synthetic acid rock drainage, and simple NaNO3 electrolyte. Metal adsorption data are combined with isotopic measurements of dissolved Cu (65Cu/63Cu) and Zn (66Zn/64Zn) in each of the experiments. Fractionation of Cu and Zn isotopes occurs during adsorption of the metal onto amorphous ferric oxyhydroxide. The adsorption data are modeled successfully using the diffuse double layer model in PHREEQC. The isotopic data are best described by a closed system, equilibrium exchange model. The fractionation factors (αsoln-solid) are 0.99927 ± 0.00008 for Cu and 0.99948 ± 0.00004 for Zn or, alternately, the separation factors (Δsoln-solid) are -0.73 ± 0.08‰ for Cu and -0.52 ± 0.04‰ for Zn. These factors indicate that the heavier isotope preferentially adsorbs onto the oxyhydroxide surface, which is consistent with shorter metal-oxygen bonds and lower coordination number for the metal at the surface relative to the aqueous ion. Fractionation of Cu isotopes also is greater than that for Zn isotopes. Limited isotopic data for adsorption of Cu, Fe(II), and Zn onto amorphous ferric oxyhydroxide suggest that isotopic fractionation is related to the intrinsic equilibrium constants that define aqueous metal interactions with oxyhydroxide surface sites. Greater isotopic fractionation occurs with stronger metal binding by the oxyhydroxide with Cu > Zn > Fe(II).

  17. Fractionation of Cu and Zn isotopes during adsorption onto amorphous Fe(III) oxyhydroxide: Experimental mixing of acid rock drainage and ambient river water

    Science.gov (United States)

    Balistrieri, L.S.; Borrok, D.M.; Wanty, R.B.; Ridley, W.I.

    2008-01-01

    Fractionation of Cu and Zn isotopes during adsorption onto amorphous ferric oxyhydroxide is examined in experimental mixtures of metal-rich acid rock drainage and relatively pure river water and during batch adsorption experiments using synthetic ferrihydrite. A diverse set of Cu- and Zn-bearing solutions was examined, including natural waters, complex synthetic acid rock drainage, and simple NaNO3 electrolyte. Metal adsorption data are combined with isotopic measurements of dissolved Cu (65Cu/63Cu) and Zn (66Zn/64Zn) in each of the experiments. Fractionation of Cu and Zn isotopes occurs during adsorption of the metal onto amorphous ferric oxyhydroxide. The adsorption data are modeled successfully using the diffuse double layer model in PHREEQC. The isotopic data are best described by a closed system, equilibrium exchange model. The fractionation factors (??soln-solid) are 0.99927 ?? 0.00008 for Cu and 0.99948 ?? 0.00004 for Zn or, alternately, the separation factors (??soln-solid) are -0.73 ?? 0.08??? for Cu and -0.52 ?? 0.04??? for Zn. These factors indicate that the heavier isotope preferentially adsorbs onto the oxyhydroxide surface, which is consistent with shorter metal-oxygen bonds and lower coordination number for the metal at the surface relative to the aqueous ion. Fractionation of Cu isotopes also is greater than that for Zn isotopes. Limited isotopic data for adsorption of Cu, Fe(II), and Zn onto amorphous ferric oxyhydroxide suggest that isotopic fractionation is related to the intrinsic equilibrium constants that define aqueous metal interactions with oxyhydroxide surface sites. Greater isotopic fractionation occurs with stronger metal binding by the oxyhydroxide with Cu > Zn > Fe(II).

  18. 2 CFR 182.40 - How is the guidance maintained?

    Science.gov (United States)

    2010-01-01

    ... AND AGREEMENTS Reserved GOVERNMENTWIDE REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) § 182.40 How is the guidance maintained? The OMB publishes proposed changes to the guidance in the... groups, and then issues any changes to the guidance in final form. ...

  19. Free-end space maintainers: design, utilization and advantages.

    Science.gov (United States)

    Barbería, Elena; Lucavechi, Tania; Cárdenas, Dora; Maroto, Myriam

    2006-01-01

    Primary molars are a determining factor in the development of occlusion. Given their importance, when restorative treatment is notfeasible and a primary molar must be extracted, the practitioner should keep in mind the risk of losing space, and the consequent malocclusion. Preservation of the space can eliminate or reduce the needforprolonged orthodontic treatment. For that reason, there are various kinds of space maintainers and the pediatric dentist must decide which one to utilize, on the basis of general and local factors related to the child In the selection of a treatment option for space maintenance, the greatest complications occur when the first permanent molar has not yet erupted A large variety of appliances have been devised to deal with this situation. This article proposes the use of a removable space maintainer that is open on one end and can be employed to guide the first permanent molar, maintaining the integrity of the mucous membrane and serving as a prosthetic appliance, preventing the complications and contraindications often caused by sub-gingival maintainers.

  20. Banded vs Bonded Space Maintainers: Finding Better Way Out

    Science.gov (United States)

    Kumar Pandit, Inder; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika

    2014-01-01

    ABSTRACT Objectives: Of this in vivo study was to evaluate various space maintainers in terms of survival rate, gingival health and presence of caries. Design: A total of 60 extraction sites in the age group of 4 to 9 years were divided into four groups and different space maintainers were placed in them viz (conventional band and loop, prefabricated band with custom made loop, Ribbond, Super splint). Results: Prefabricated bands with custom made loop showed maximum success rates (84.6%), while super splint (33.33%) was found to be least successful. In terms of gingival health, prefabricated band with custom made loop reported minimum cases with poor gingival health (27.2%), while maximum cases with poor gingival health (50%) were reported with Super splint. None of the space maintainers developed caries at the end of 9 months. How to cite this article: Setia v, Pandit IK, Srivastava N, Gugnani N, Gupta M. Banded vs Bonded Space Maintainers: Finding Better Way Out. Int J Clin Pediatr Dent 2014;7(2):97-104. PMID:25356008

  1. [Maintaining the proper distance for nurses working in the home].

    Science.gov (United States)

    Estève, Sonia

    2016-01-01

    Health professionals must be able to respond to many different situations which require technical knowledge and self-control. Particularly when working in the patient's home, nurses must know how to maintain a proper distance to protect themselves from burnout. In this respect, the practice analysis constitutes an adapted support tool. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. 76 FR 79553 - Maintaining Access to Emergency Liquidity

    Science.gov (United States)

    2011-12-22

    ... Federal Reserve District Bank. 12 CFR 201.51. While the CLF is a special liquidity facility for the credit... ADMINISTRATION 12 CFR Part 741 RIN 3133-AD96 Maintaining Access to Emergency Liquidity AGENCY: National Credit... regulation to require federally insured credit unions (FICUs) to have access to backup federal...

  3. 77 FR 44503 - Maintaining Access to Emergency Liquidity

    Science.gov (United States)

    2012-07-30

    ... maintain an adequate liquidity risk management process raises safety and soundness concerns. See 75 FR... Interagency Policy Statement on Funding and Liquidity Risk Management (Liquidity Policy Statement),\\5\\ were... complexity, to have a management process for identifying, measuring, monitoring, and controlling liquidity...

  4. Maintaining Healthy Behaviors Following Weight Loss: A Grounded Theory Approach

    Science.gov (United States)

    Zunker, Christie; Cox, Tiffany L.; Ard, Jamy D.; Ivankova, Nataliya V.; Rutt, Candace D.; Baskin, Monica L.

    2011-01-01

    This study explored the process of how women maintained their healthy behaviors after a weight management program using a grounded theory approach. We conducted 2 focus groups and 23 interviews with a purposeful sample of African American and Caucasian women aged 30 and older who lost greater than 5% of their body weight during a weight management…

  5. Motivational Influences on Performance Maintained by Food Reinforcement

    Science.gov (United States)

    North, Stephen T.; Iwata, Brian A.

    2005-01-01

    In Study 1, we examined the independent effects of reinforcer consumption during sessions and meal consumption prior to sessions on performance maintained by food reinforcement. Nine individuals with developmental disabilities participated. On alternate days, a preferred edible item was delivered during (a) seven sessions conducted before lunch…

  6. Maintaining Program Understanding - Issues, Tools, and Future Directions

    DEFF Research Database (Denmark)

    Vestdam, Thomas; Nørmark, Kurt

    2004-01-01

    The understanding of a program is a key aspect of software development. The understanding is a prerequisite for the initial development efforts. This paper is concerned with the challenge of maintaining the program understanding with the purpose of supporting later phases in the program life time...

  7. Impact of Agile Software Development Model on Software Maintainability

    Science.gov (United States)

    Gawali, Ajay R.

    2012-01-01

    Software maintenance and support costs account for up to 60% of the overall software life cycle cost and often burdens tightly budgeted information technology (IT) organizations. Agile software development approach delivers business value early, but implications on software maintainability are still unknown. The purpose of this quantitative study…

  8. Maintaining Legitimacy: Controversies, Orders of Worth and Public Justifications

    NARCIS (Netherlands)

    Patriotta, G.; Gond, J.-P.; Schultz, F.

    2011-01-01

    We build on Boltanski and Thévenot's theory of justification to account for the ways in which different stakeholder groups actively engage with discourses and objects to maintain the legitimacy of institutions that are relevant to their activity. We use this framework to analyse a controversy emergi

  9. 48 CFR 6.202 - Establishing or maintaining alternative sources.

    Science.gov (United States)

    2010-10-01

    ... emergency or industrial mobilization; (3) Be in the interest of national defense in establishing or maintaining an essential engineering, research, or development capability to be provided by an educational or... history of high demand; or (6) Satisfy a critical need for medical, safety, or emergency supplies....

  10. Maintaining Equivalent Cut Scores for Small Sample Test Forms

    Science.gov (United States)

    Dwyer, Andrew C.

    2016-01-01

    This study examines the effectiveness of three approaches for maintaining equivalent performance standards across test forms with small samples: (1) common-item equating, (2) resetting the standard, and (3) rescaling the standard. Rescaling the standard (i.e., applying common-item equating methodology to standard setting ratings to account for…

  11. 24 CFR 1003.505 - Records to be maintained.

    Science.gov (United States)

    2010-04-01

    ... DEVELOPMENT COMMUNITY DEVELOPMENT BLOCK GRANTS FOR INDIAN TRIBES AND ALASKA NATIVE VILLAGES Grant... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Records to be maintained. 1003.505 Section 1003.505 Housing and Urban Development Regulations Relating to Housing and Urban Development...

  12. Genetic and somatic effects in animals maintained on tritiated water

    Energy Technology Data Exchange (ETDEWEB)

    Carsten, A.L.; Brooks, A.; Commerford, S.L.; Cronkite, E.P.

    1981-01-01

    The possible genetic (dominant lethal mutations (DLM) and cytogenetic changes in the regenerating liver) and somatic (hematopoietic stem cell changes, growth and nonspecific life time shortening) effects in mice maintained on tritiated water (HTO) over two generations was investigated. Results to date are summarized. (ACR)

  13. 399 Maintaining Discipline and Orderliness in Secondary Education ...

    African Journals Online (AJOL)

    User

    2010-10-17

    Oct 17, 2010 ... The result revealed that all the strategies investigated were suitable for maintaining ... noted that 20% of the adolescents experience serious psychological conflicts, ... atmosphere conducive to effective teaching and learning. ... instance, both the principals' and teachers' leadership styles can affect the.

  14. Establishing and Maintaining Boundaries in Teacher-Student Relationships

    Science.gov (United States)

    Bernstein-Yamashiro, Beth; Noam, Gil G.

    2013-01-01

    Because schools rarely provide guidelines for teachers that outline how they should conduct personal relationships with students, teachers must wrestle individually with how to establish, communicate, and maintain clear boundaries in their interactions. As schools work to become more personal environments, school administrators will need to help…

  15. The potential role of agroforestry in maintaining soil fertility on ...

    African Journals Online (AJOL)

    Organic fertilizers play a significant role in maintaining soil fertility on these ... soil and aid in nutrient cycling by providing prunings as a source of organic matter. ... that include improving soil fertility, and the conservation of soil and moisture, ...

  16. Guidelines for Beginning and Maintaining a Toy Lending Library.

    Science.gov (United States)

    Rettig, Michael A.

    1998-01-01

    Toy-lending libraries provide parents and professionals with opportunities for shared play and the loan of toys. This article reviews the history of toy-lending libraries and the purpose of Lekoteks, the Swedish toy library. Guidelines and suggestions for developing and maintaining a toy-lending library are discussed. (JPB)

  17. Beijing's Convention and Exhibition Industry Maintains Good Momentum

    Institute of Scientific and Technical Information of China (English)

    Xiong Jiuling

    2011-01-01

    @@ In recent years, Beijing's conven-tion and exhibition industry has maintained a good development momentum with expanding scale and improving facilities, becoming an inseparable part of the city's modern service sector.The development of the convention and exhibition industry has played an active role in perfecting the capital's functions, optimizing the industrial structure and enhancing the city's radiation capabilities.

  18. Nuclear policy impacts at the national laboratories: maintaining the deterrence

    Energy Technology Data Exchange (ETDEWEB)

    Beck, James Bradley [Los Alamos National Laboratory

    2010-08-24

    In this presentation, the author will discuss recent nuclear policy impacts, including the 2010 Nuclear Posture Review, and the impacts they have on maintaining the nuclear deterrent. Specifically, he will highlight some of the remaining questions and challenges that remain to the nation and to the national laboratories. (auth)

  19. 4 CFR 200.14 - Responsibility for maintaining adequate safeguards.

    Science.gov (United States)

    2010-01-01

    ... identifiable personal data and automated systems shall be adequately trained in the security and privacy of... records in which identifiable personal data are processed or maintained, including all reports and output... personal records or data; must minimize, to the extent practicable, the risk that skilled technicians...

  20. Impact of Agile Software Development Model on Software Maintainability

    Science.gov (United States)

    Gawali, Ajay R.

    2012-01-01

    Software maintenance and support costs account for up to 60% of the overall software life cycle cost and often burdens tightly budgeted information technology (IT) organizations. Agile software development approach delivers business value early, but implications on software maintainability are still unknown. The purpose of this quantitative study…

  1. Guide to Operating and Maintaining EnergySmart Schools

    Science.gov (United States)

    US Department of Energy, 2010

    2010-01-01

    The guide allows users to adapt and implement suggested O&M (operating and maintaining) strategies to address specific energy efficiency goals. It recognizes and expands on existing tools and resources that are widely used throughout the high-performance school industry. The guide is organized into the following sections: (1) Chapter 1:…

  2. Maintaining Continuity of Knowledge of Spent Fuel Pools: Tool Survey

    Energy Technology Data Exchange (ETDEWEB)

    Benz, Jacob M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smartt, Heidi A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tanner, Jennifer E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); MacDougall, Matthew R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-08-30

    This report examines supplemental tools that can be used in addition to optical surveillance cameras to maintain CoK in low-to-no light conditions, and increase the efficiency and effectiveness of spent fuel CoK, including item counting and ID verification, in challenging conditions.

  3. Short course on St-02 applications of isotope dilutions and isotopic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Miller, P.

    1998-01-05

    This short course includes information on these topics and subtopics: (I) Nuclear Properties: (A) Historic roots; (B) Nomenclature; (C) Nuclear Stability and abundance; (D) Uses of isotopic techniques; (II) Instrumentation: (A) Sources; (B) Mass resolving elements; (C) Detectors; (III) Making Isotopic Measurements by ICP-MS: (A) Deadtime Correction; (B) Mass Discrimination; (C) Signal /Noise considerations; (IV) Applications and examples: (A) Isotope dilution; (B) Double Spike; (C) Biological Application; (D) Environmental Application; (E) Geological.

  4. Mechanical properties of different types of space maintainers

    Science.gov (United States)

    Beldiman, M.-A.; Mârţu, I.; Leiţoiu, B.; Luchian, I.; Lupescu, O.; Bârcă, E. S.

    2015-11-01

    Currently, inside the oral cavity, the dental space maintainers are subjected to forces exerted on them when performing various functions; therefore, it is important to know how each of these mechanisms behave and respond to forces that are applied directly to them. The mechanical properties of the materials used in dentistry are defined by a set of characteristics representing the behaviour of their particular working conditions and it is qualitatively expressed by a number of parameters.The study aimed to determine the pressing force that can be taken by four 4 types of space maintainers frequently used in practice - fixed and removable, applied on four samples realized with human teeth extracted for orthodontic purposes. Static tests were carried out on a machine type short WDW-5 EC with a maximum force of 5 kN and a loading speed of 5 mm/min by a special testing machine, with an innovative appliance; data recording was automatically performed, using a computer with a special program that present the specific diagrams. Experimental determinations included the following aspects: to determine the maximum force that can be supported by each sample, and to observe the deformations. The values obtained indicate that the best option in terms of behavior under the conditions specified is the removable appliance, and the less functional version is the fixed space maintainer using brackets. According to tests conducted, the fracture strength was found to be more important for fixed space maintainers (band and loop, for example) so, in practice is using more frequent these types of space maintainers.

  5. Isotope pattern deconvolution as rising tool for isotope tracer studies in environmental research

    Science.gov (United States)

    Irrgeher, Johanna; Zitek, Andreas; Prohaska, Thomas

    2014-05-01

    During the last decade stable isotope tracers have emerged as versatile tool in ecological research. Besides 'intrinsic' isotope tracers caused by the natural variation of isotopes, the intentional introduction of 'extrinsic' enriched stable isotope tracers into biological systems has gained significant interest. Hereby the induced change in the natural isotopic composition of an element allows amongst others for studying the fate and fluxes of metals, trace elements and species in organisms or provides an intrinsic marker or tag of particular biological samples. Due to the shoreless potential of this methodology, the number of publications dealing with applications of isotope (double) spikes as tracers to address research questions in 'real world systems' is constantly increasing. However, some isotope systems like the natural Sr isotopic system, although potentially very powerful for this type of application, are still rarely used, mainly because their adequate measurement/determination poses major analytical challenges; as e.g. Sr is available in significant amounts in natural samples. In addition, biological systems underlie complex processes such as metabolism, adsorption/desorption or oxidation/reduction. As a consequence, classic evaluation approaches such as the isotope dilution mass spectrometry equation are often not applicable because of the unknown amount of tracer finally present in the sample. Isotope pattern deconvolution (IPD), based on multiple linear regression, serves as simplified alternative data processing strategy to double spike isotope dilution calculations. The outstanding advantage of this mathematical tool lies in the possibility of deconvolving the isotope pattern in a spiked sample without knowing the quantities of enriched isotope tracer being incorporated into the natural sample matrix as well as the degree of impurities and species-interconversion (e.g. from sample preparation). Here, the potential of IPD for environmental tracer

  6. Stable isotope production with laser techniques; Production d`isotopes stables a l`aide des techniques laser

    Energy Technology Data Exchange (ETDEWEB)

    Petit, A. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`Enrichissement

    1994-12-31

    Laser properties may be used for stable isotope production either by selective photoionization of an atom particular isotope, either by selective photodissociation of a molecule. Principles of both processes are reviewed and examples of calcium 43 isotope separation through photoionization and of carbon and oxygen isotope separation by photodissociation are presented. 4 figs., 1 tab., 11 refs.

  7. The anomalous quadrupole collectivity in Te isotopes

    CERN Document Server

    Qi, Chong

    2016-01-01

    We present systematic calculations on the spectroscopy and transition properties of even-even Te isotopes by using the large-scale configuration interaction shell model approach with a realistic interaction. These nuclei are of particular interest since their yrast spectra show a vibrational-like equally-spaced pattern but the few known E2 transitions show anomalous rotational-like behavior, which cannot be reproduced by collective models. Our calculations reproduce well the equally-spaced spectra of those isotopes as well as the constant behavior of the $B(E2)$ values in $^{114}$Te. The calculated $B(E2)$ values for neutron-deficient and heavier Te isotopes show contrasting different behaviors along the yrast line. The $B(E2)$ of light isotopes can exhibit a nearly constant bevavior upto high spins. We show that this is related to the enhanced neutron-proton correlation when approaching $N=50$.

  8. Separation of Isotopes via Dynamical Delocalization

    Institute of Scientific and Technical Information of China (English)

    Farhan Saif

    2008-01-01

    Based on the dynamical de-localization phenomenon we show that different isotopes of a material can be separated.We explain that the suggested scheme can be realized in the laboratory using presently available experimental facilities.

  9. Preparation of Metallic Isotope 26Mg

    Institute of Scientific and Technical Information of China (English)

    WuXiaolei; ZhangFuming; GanZaiguo; GuoJunsheng; QinZhi

    2003-01-01

    Some special isotope material is usually used in nuclear experiments. It can be served as ion beam or target. When new superheavy nuclide 265Bh (Z=107) is synthesized, a reaction of 243Am target with 26Mg ion beamis selected to produce new isotope 265Bh. The preparation and production of this rare and extremely expensive isotope 26 Mg used for ion beam substance will be a key problem in synthesizing experiment of 265Bh. Theavailable chemical form of isotope 26Mg in commercial product usually is oxide or other compound, which are not required in our experiment. They need to be transformed to metal form as a proper working substance in ion source.

  10. Nuclear Astrophysics with rare isotopes at FRIB

    Science.gov (United States)

    Schatz, Hendrik

    2011-05-01

    The Facility for Rare Isotope Beams (FRIB) currently under construction at Michigan State University will be one of the worlds’ most powerful accelerators to produce rare isotopes. These isotopes live only fractions of seconds, but their properties are imprinted onto the composition of the visible universe and the nature of stellar explosions. FRIB will produce for the first time many of the rare isotopes that are part of the rapid neutron capture process, responsible for the origin of heavy elements; it will measure reaction rates that govern stellar explosions such as supernovae, novae, and X-ray bursts; and it will produce the same exotic nuclei that form the crust of neutron stars. I will discuss how data from FRIB, together with new observational data, promise to address many open questions at the intersection of nuclear physics and astronomy, including the chemical evolution of our Galaxy, the nuclear energy sources of stellar explosions, and the nature of neutron stars.

  11. Quantification of isotopic turnover in agricultural systems

    Science.gov (United States)

    Braun, A.; Auerswald, K.; Schnyder, H.

    2012-04-01

    The isotopic turnover, which is a proxy for the metabolic rate, is gaining scientific importance. It is quantified for an increasing range of organisms, from microorganisms over plants to animals including agricultural livestock. Additionally, the isotopic turnover is analyzed on different scales, from organs to organisms to ecosystems and even to the biosphere. In particular, the quantification of the isotopic turnover of specific tissues within the same organism, e.g. organs like liver and muscle and products like milk and faeces, has brought new insights to improve understanding of nutrient cycles and fluxes, respectively. Thus, the knowledge of isotopic turnover is important in many areas, including physiology, e.g. milk synthesis, ecology, e.g. soil retention time of water, and medical science, e.g. cancer diagnosis. So far, the isotopic turnover is quantified by applying time, cost and expertise intensive tracer experiments. Usually, this comprises two isotopic equilibration periods. A first equilibration period with a constant isotopic input signal is followed by a second equilibration period with a distinct constant isotopic input signal. This yields a smooth signal change from the first to the second signal in the object under consideration. This approach reveals at least three major problems. (i) The input signals must be controlled isotopically, which is almost impossible in many realistic cases like free ranging animals. (ii) Both equilibration periods may be very long, especially when the turnover rate of the object under consideration is very slow, which aggravates the first problem. (iii) The detection of small or slow pools is improved by large isotopic signal changes, but large isotopic changes also involve a considerable change in the input material; e.g. animal studies are usually carried out as diet-switch experiments, where the diet is switched between C3 and C4 plants, since C3 and C4 plants differ strongly in their isotopic signal. The

  12. The production of stable isotopes in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Urgel, M.; Iglesias, J.; Casas, J.; Saviron, J. M.; Quintanilla, M.

    1965-07-01

    The activities developed in the field of the production of stable isotopes by means of ion-exchange chromatography and thermal diffusion techniques are reported. The first method was used to study the separation of the nitrogen and boron isotopes, whereby the separation factor was determined by the break through method. Values ranging from 1,028 to 1,022 were obtained for the separation factor of nitrogen by using ammonium hydroxide solutions while the corresponding values as obtained for boron amounted to 1,035-1,027 using boric acid solutions. Using ammonium chloride or acetate and sodium borate, respectively, resulted in the obtention of values for the separation factor approaching unity. The isotopic separation has been carried out according to the method of development by displacement. The separation of the isotopes of the noble gases, oxygen, nitrogen and carbon has been accomplished resorting to the method of thermal diffusion. (Author) 16 refs.

  13. Use of fluorescent screens for isotope radiography

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, S. K.

    1979-01-01

    Radiographic examination can be performed on items beyond the limitation of conventional isotope radiography without a great loss of resolution. With proper film and screen selection and scatter radiation control, fluorescent screens can be a valuable additional tool for radiography.

  14. Carbon isotopic fractionation in heterotrophic microbial metabolism

    Science.gov (United States)

    Blair, N.; Leu, A.; Munoz, E.; Olsen, J.; Kwong, E.; Des Marais, D.

    1985-01-01

    Differences in the natural-abundance carbon stable isotopic compositions between products from aerobic cultures of Escherichia coli K-12 were measured. Respired CO2 was 3.4 percent depleted in C-13 relative to the glucose used as the carbon source, whereas the acetate was 12.3 percent enriched in C-13. The acetate C-13 enrichment was solely in the carboxyl group. Even though the total cellular carbon was only 0.6 percent depleted in C-13, intracellular components exhibited a significant isotopic heterogeneity. The protein and lipid fractions were -1.1 and -2.7 percent, respectively. Aspartic and glutamic acids were -1.6 and +2.7 percent, respectively, yet citrate was isotopically identical to the glucose. Probable sites of carbon isotopic fractionation include the enzyme, phosphotransacetylase, and the Krebs cycle.

  15. Isotope effects of hydrogen and atom tunnelling

    Science.gov (United States)

    Buchachenko, A. L.; Pliss, E. M.

    2016-06-01

    The abnormally high mass-dependent isotope effects in liquid-phase hydrogen (deuterium) atom transfer reactions, which are customarily regarded as quantum effects, are actually the products of two classical effects, namely, kinetic and thermodynamic ones. The former is determined by the rate constants for atom transfer and the latter is caused by nonbonded (or noncovalent) isotope effects in the solvation of protiated and deuterated reacting molecules. This product can mimic the large isotope effects that are usually attributed to tunnelling. In enzymatic reactions, tunnelling is of particular interest; its existence characterizes an enzyme as a rigid molecular machine in which the residence time of reactants on the reaction coordinate exceeds the waiting time for the tunnelling event. The magnitude of isotope effect becomes a characteristic parameter of the internal dynamics of the enzyme catalytic site. The bibliography includes 61 references.

  16. Beam delivery for stable isotope separation

    Science.gov (United States)

    Forbes, Andrew; Strydom, Hendrick J.; Botha, Lourens R.; Ronander, Einar

    2002-10-01

    In the multi-photon dissociation process of Carbon isotope enrichment, IR photons are used to selectively excite a molecule with the given isotopic base element. This enrichment process is very sensitive to the beam's intensity and wavelength. Because the intensity is determined by the propagation of the field, the enrichment factors are also very dependent on the field propagation. In this paper, the influence of the wavelength and intensity of the beam, on the isotope selective dissociation of a CFC compound is investigated both experimentally and theoretically. Consideration is also given to some of the factors that influence the delivery of various beams to the reactor chamber, and their subsequent propagation through the reactor. The results show that suitable beam forming can lead to an improved isotope separation process.

  17. On the progress in stable isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Prusakov, V.N. [Kurchatov Institute, Moscow (Russian Federation)

    1994-12-31

    The principles and process of centrifuge isotope separation are reviewed; the fundamental advantage of the centrifuge over gaseous diffusion arises from the fact that the primary isotope separation effect occurs at thermodynamic equilibrium; thus, gas centrifuge enrichment uses only about 1/20 to 1/30 of the electricity per SWU (separation work unit) consumed by gaseous diffusion. The various substances that can be used in centrifuge isotope separation are listed (fluorides, oxyfluorides, {pi}-complexes, boron hydrides, metal-organic compounds, halides...). The centrifuge method productivity is much greater than with the electromagnetic separation technique; examples of centrifuge stable and radioactive isotope separation are given; the method of the residue reduction is also presented with the example of separating radioactive krypton-85 out of a nuclear reactor krypton blend. 4 figs.

  18. Development of proliferation resistant isotope separation technology

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Doyoung; Ko, Kwanghoon; Kim, Taeksoo; Park, Hyunmin; Lim, Gwon; Cha, Yongho; Han, Jaemin; Baik, Sunghoon; Cha, Hyungki

    2012-02-15

    This project was accomplished with an aim of establishing the industrial facilities for isotope separation in Korea. The experiment for the measurement of neutrino mass that has been an issue in physics, needs very much of enriched calcium-48 isotope. However, calcium-48 isotope can be produced only by the electro-magnetic method and, thus, its price is very expensive. Therefore, we expect that ALSIS can replace the electro-magnetic method for calcium-48 isotope production. In this research stage, the research was advanced systematically with core technologies, such as atomic vapor production, the measurement of vapor characteristics and stable and powerful laser development. These researches will be the basis of the next research stages. In addition, the international research trends and cooperation results are reported in this report.

  19. Stable Oxygen-18 and Deuterium Isotopes

    DEFF Research Database (Denmark)

    Müller, Sascha

    development within a given lowland headwater catchment (stream water isotopes). Based on our investigations on the precipitation isotopic composition a local meteoric water line (LMWL) was constructed and expressed as: δ2H=7.4 δ18O + 5.36‰. Moreover, we showed that under maritime temperature climate influence......, humidity is the main driver for the temporal and spatial isotopic development and temperature plays only a secondary role. Based on our investigations at a coastal lagoon aquifer we could improve quantifications of seasonal saltwater-wedge dynamics, based on isotopic tracers combined with salinity. We can...... link the observed seasonal regression/transgression pattern to the inland recharge cycle, which is expressed in hydraulic head configuration and submarine groundwater discharge rates at the fieldsite. Nonetheless, those observed dynamics could not be simulated due to numerical limitations. By the use...

  20. Isotope engineering of carbon nanotube systems.

    Science.gov (United States)

    Simon, F; Kramberger, Ch; Pfeiffer, R; Kuzmany, H; Zólyomi, V; Kürti, J; Singer, P M; Alloul, H

    2005-07-01

    The synthesis of a unique isotope engineered system, double-wall carbon nanotubes with natural carbon outer and highly 13C enriched inner walls, is reported from isotope enriched fullerenes encapsulated in single-wall carbon nanotubes (SWCNTs). The material allows the observation of the D line of the highly defect-free inner tubes that can be related to a curvature induced enhancement of the electron-phonon coupling. Ab initio calculations explain the inhomogeneous broadening of inner tube Raman modes due to the distribution of different isotopes. Nuclear magnetic resonance shows a significant contrast of the isotope enriched inner SWCNTs compared to other carbon phases and provides a macroscopic measure of the inner tube mass content. The high curvature of the small diameter inner tubes manifests in an increased distribution of the chemical shift tensor components.

  1. Robust optical carbon dioxide isotope analyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Isotopic analysis of carbon dioxide is an important tool for characterization of the exchange and transformation of carbon between the biosphere and the atmosphere....

  2. Na Cauda do Cometa

    Science.gov (United States)

    Voelzke, M. R.

    2009-01-01

    Quando viam um cometa, os antigos gregos imaginavam uma estrela com uma vasta cabeleira. Não à toa, a palavra deriva do termo koma, que significa cabelo. Constituídos por fragmentos de gelo e gases, os cometas possuem um núcleo sólido, que pode ter vários quilômetros de diâmetro, e uma cauda que sempre aponta na direção contrária ao Sol, devido aos ventos solares. Graças à aparência de pontos luminosos em movimento (ao contrário de outros astros, que parecem estáticos), esses corpos celestes foram interpretados por diferentes povos com muito misticismo, inspirando mitos tanto de boas-novas como de maus presságios. Conheça algumas dessas histórias:

  3. O real na psicose

    Directory of Open Access Journals (Sweden)

    Maurício Castejón Herrmann

    2004-06-01

    Full Text Available Este artigo discute a noção de real na psicose, a partir das formulações de Lacan sobre o tema, presentes no Seminário 3 - As Psicoses, no Seminário 20 - Mais, Ainda e no texto Televisão. Considerando-se que a concepção de real tem uma indicação clínica, a hipótese que se formula é a de que a noção de real trabalhada no Seminário 20, Mais, Ainda representa uma continuidade da concepção de real desenvolvida no Seminário 3, As Psicoses

  4. NA48 prototype calorimeter

    CERN Document Server

    1990-01-01

    This is a calorimeter, a detector which measures the energy of particles. When in use, it is filled with liquid krypton at -152°C. Electrons and photons passing through interact with the krypton, creating a shower of charged particles which are collected on the copper ribbons. The ribbons are aligned to an accuracy of a tenth of a millimetre. The folding at each end allows them to be kept absolutely flat. Each shower of particles also creates a signal in scintillating material embedded in the support disks. These flashes of light are transmitted to electronics by the optical fibres along the side of the detector. They give the time at which the interaction occurred. The photo shows the calorimeter at NA48, a CERN experiment which is trying to understand the lack of anti-matter in the Universe today.

  5. Leadeship: na effective relationship

    OpenAIRE

    Sergio Roberto Guimarães Pantoja

    2005-01-01

    Resumo: O presente trabalho tem por objetivo analisar a eficácia da liderança em três instituições de ensino superior em São Luís -MA, sendo a instituição A (particular), a B (pública federal) e a C (pública estadual). Adotou-se os estilos de liderança: democrático, autocrático e liberal, baseando-se na Teoria dos Estilos de Kurt Lewin e seus colaboradores e nas qualidades de liderança (objetividade, compreensão dos outros, flexibilidade, comunicação e autoridade), definidas por Uris A.(196...

  6. Raytracing na GPU

    OpenAIRE

    Straňák, Marek

    2011-01-01

    Raytracing je základnou technikou pro vizualizaci trojrozměrných objektů. Cílem práce je demonstrovat možnost implementace sledovaní paprsků pomocí grafického akcelerátoru.  Popíšem základní algoritmus a jeho modifikovanou verzi, která byla implementována pomocí jazyka CUDA C. Výsledný raytracer je optimalizovaný pro dynamické scény. Pro tento účel byla použita akcelerační struktura KD strom, hierarchické obalové tělesa a přenos dat pomocí PBO. Pro realističtější výstupy byla také implementov...

  7. Comprometimento pulmonar na leptospirose

    Directory of Open Access Journals (Sweden)

    Jorge Eduardo Manhães de Carvalho

    1992-03-01

    Full Text Available Em 23 pacientes com leptospirose apresentando comprometimento pulmonar, internados no Hospital Universitário Antônio Pedro da XJFF, Niterói, hemoptise e hemoptóicos foram observados em 21,7% e 30,4%, respectivajnente. Gasometria arterial revelou hipoxemia e hipocapnia na maioria dos casos. Radiografia de tórax em 15 pacientes mostrou comprometimento alveolar em 60%, comprometimento intersticial-reticular em 6%, padrão misto (alveolar e intersticial em20%e ausência de alterações radiológicas em 14%. A necrópsiade 13 pacientes mostrou edema, congestão e hemorragia nos pulmões em 100% dos casos. A hemorragia foi focal em 46% e difusa em 54% dos casos. Houve formação de membrana hialina em 30% e trombos de fibrina em 46% dos pulmões estudados, o que estabelece o diagnóstico da coagulação intravascular disseminada e a ocorrência da síndrome de angústia respiratória na leptospirose.Tostudy thepulmonary complications in leptospirosis case records of 23 such patients admitted at the Hospital Universitário Antônio Pedro, Universidade Federal Fluminense, Niterói, Brasil, were reviewed. Hemoptysis were seen in 21.7% and sputal blood in 30.4% of patients. Arterial gasometry detected hypoxemia and hypocapnia in most cases. Thoracic radiology showed an alveolar pattern in 60% of the patients, alveolo-interstitial in 20%, interstitial in 6%, and in 14% the lungs were considered to be normal Necropsy of 13 cases showed edema, congestion and hemorrhage in the lungs in all cases. Hyaline membrane was found in 30% and fibrin thrombi in 46% of these cases, resulting in a diagnosis of adult respiratory distress syndrome and acute disseminated intravascular coagulation (consumption coagulopathy in leptospirosis.

  8. Iron isotope biogeochemistry of Neoproterozoic marine shales

    Science.gov (United States)

    Kunzmann, Marcus; Gibson, Timothy M.; Halverson, Galen P.; Hodgskiss, Malcolm S. W.; Bui, Thi Hao; Carozza, David A.; Sperling, Erik A.; Poirier, André; Cox, Grant M.; Wing, Boswell A.

    2017-07-01

    Iron isotopes have been widely applied to investigate the redox evolution of Earth's surface environments. However, it is still unclear whether iron cycling in the water column or during diagenesis represents the major control on the iron isotope composition of sediments and sedimentary rocks. Interpretation of isotopic data in terms of oceanic redox conditions is only possible if water column processes dominate the isotopic composition, whereas redox interpretations are less straightforward if diagenetic iron cycling controls the isotopic composition. In the latter scenario, iron isotope data is more directly related to microbial processes such as dissimilatory iron reduction. Here we present bulk rock iron isotope data from late Proterozoic marine shales from Svalbard, northwestern Canada, and Siberia, to better understand the controls on iron isotope fractionation in late Proterozoic marine environments. Bulk shales span a δ 56Fe range from -0.45 ‰ to +1.04 ‰ . Although δ 56Fe values show significant variation within individual stratigraphic units, their mean value is closer to that of bulk crust and hydrothermal iron in samples post-dating the ca. 717-660 Ma Sturtian glaciation compared to older samples. After correcting for the highly reactive iron content in our samples based on iron speciation data, more than 90% of the calculated δ 56Fe compositions of highly reactive iron falls in the range from ca. -0.8 ‰ to +3 ‰ . An isotope mass-balance model indicates that diagenetic iron cycling can only change the isotopic composition of highly reactive iron by oxygen levels. Alternatively, increasing oxygen levels would have led to a higher proportion of Fe(II) being oxidized, without decreasing the initial size of the ferrous seawater iron pool. We consider the latter explanation as the most likely. According to this hypothesis, the δ 56Fe record reflects the redox evolution of Earth's surface environments. δ 56Fe values in pre-Sturtian samples

  9. Keratin decomposition by trogid beetles: evidence from a feeding experiment and stable isotope analysis

    Science.gov (United States)

    Sugiura, Shinji; Ikeda, Hiroshi

    2014-03-01

    The decomposition of vertebrate carcasses is an important ecosystem function. Soft tissues of dead vertebrates are rapidly decomposed by diverse animals. However, decomposition of hard tissues such as hairs and feathers is much slower because only a few animals can digest keratin, a protein that is concentrated in hairs and feathers. Although beetles of the family Trogidae are considered keratin feeders, their ecological function has rarely been explored. Here, we investigated the keratin-decomposition function of trogid beetles in heron-breeding colonies where keratin was frequently supplied as feathers. Three trogid species were collected from the colonies and observed feeding on heron feathers under laboratory conditions. We also measured the nitrogen (δ15N) and carbon (δ13C) stable isotope ratios of two trogid species that were maintained on a constant diet (feathers from one heron individual) during 70 days under laboratory conditions. We compared the isotopic signatures of the trogids with the feathers to investigate isotopic shifts from the feathers to the consumers for δ15N and δ13C. We used mixing models (MixSIR and SIAR) to estimate the main diets of individual field-collected trogid beetles. The analysis indicated that heron feathers were more important as food for trogid beetles than were soft tissues under field conditions. Together, the feeding experiment and stable isotope analysis provided strong evidence of keratin decomposition by trogid beetles.

  10. Isotopes reveal contrasting water use strategies among coexisting plant species in a Mediterranean ecosystem.

    Science.gov (United States)

    Moreno-Gutiérrez, Cristina; Dawson, Todd E; Nicolás, Emilio; Querejeta, José Ignacio

    2012-10-01

    Variation in the stable carbon and oxygen isotope composition (δ13C, Δ18O) of co-occurring plant species may reflect the functional diversity of water use strategies present in natural plant communities. We investigated the patterns of water use among 10 coexisting plant species representing diverse taxonomic groups and life forms in semiarid southeast Spain by measuring their leaf δ13C and Δ18O, the oxygen isotope ratio of stem water and leaf gas exchange rates. Across species, Δ18O was tightly negatively correlated with stomatal conductance (gs), whereas δ13C was positively correlated with intrinsic water use efficiency (WUEi). Broad interspecific variation in Δ18O, δ13C and WUEi was largely determined by differences in gs, as indicated by a strong positive correlation between leaf δ13C and Δ18O across species The 10 co-occurring species segregated along a continuous ecophysiological gradient defined by their leaf δ13C and Δ18O, thus revealing a wide spectrum of stomatal regulation intensity and contrasting water use strategies ranging from 'profligate/opportunistic' (high gs, low WUEi) to 'conservative' (low gs, high WUEi). Coexisting species maintained their relative isotopic rankings in 2 yr with contrasting rainfall, suggesting the existence of species-specific 'isotopic niches' that reflect ecophysiological niche segregation in dryland plant communities. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  11. A ENGENHARIA NA ESCOLA

    Directory of Open Access Journals (Sweden)

    Valéria Pelizzer Casara

    2015-04-01

    Full Text Available Este projeto teve por objetivo principal mostrar às jovens do ensino médio, como as áreas de exatas e de engenharia podem estar inseridas em situações rotineiras por elas vivenciadas e incentivá-las para ingressarem nessas áreas. O projeto foi executado na escola de ensino Médio Nelson Horostecki na cidade de Chapecó, Santa Catarina. Mostrou-se de forma simples que as áreas de exatas e de engenharia têm aplicações práticas nas nossas vidas. No desenvolvimento do projeto, realizaram-se oficinas na escola cujo tema principal abordado foi o processo de fabricação do chocolate, visto que o mesmo é um produto muito apreciado pelas adolescentes. Dentro dessa temática, foram trabalhadas as questões que envolvem conhecimentos das áreas de exatas e de engenharia, mais especificamente a Engenharia Ambiental. O projeto auxiliou na formação cidadã e também na escolha profissional das meninas. Muitas das alunas participantes nunca haviam tido contato direto com alunos graduandos de cursos na área das exatas. Mais ainda, este projeto oportunizou a aproximação da universidade com a comunidade externa. Palavras-chave: Extensão Universitária, Ciências Exatas e Engenharia, Chocolate, Oficinas.   Engineering in the school Abstract: The main objective of this project was to show high school female students how the exact sciences and engineering can be included in their routine situations encouraging them to entering in these areas. The project was carried out at the Nelson Horostecki High School in Chapecó, Santa Catarina State, Brazil. It was showed in a simple manner how exact sciences and engineering have practical applications in our lives. Workshops were conducted in the school during the execution of the project in which the main subject was the chocolate manufacturing process, since chocolate is a product greatly appreciated by the young female people. Within this matter, the activities were performed using the knowledge of

  12. Down-Regulation of the Na+-Coupled Phosphate Transporter NaPi-IIa by AMP-Activated Protein Kinase

    Directory of Open Access Journals (Sweden)

    Miribane Dërmaku-Sopjani

    2013-11-01

    Full Text Available Background/Aims: The Na+-coupled phosphate transporter NaPi-IIa is the main carrier accomplishing renal tubular phosphate reabsorption. It is driven by the electrochemical Na+ gradient across the apical cell membrane, which is maintained by Na+ extrusion across the basolateral cell membrane through the Na+/K+ ATPase. The operation of NaPi-IIa thus requires energy in order to avoid cellular Na+ accumulation and K+ loss with eventual decrease of cell membrane potential, Cl- entry and cell swelling. Upon energy depletion, early inhibition of Na+-coupled transport processes may delay cell swelling and thus foster cell survival. Energy depletion is sensed by the AMP-activated protein kinase (AMPK, a serine/threonine kinase stimulating several cellular mechanisms increasing energy production and limiting energy utilization. The present study explored whether AMPK influences the activity of NAPi-IIa. Methods: cRNA encoding NAPi-IIa was injected into Xenopus oocytes with or without additional expression of wild-type AMPK (AMPKα1-HA+AMPKβ1-Flag+AMPKγ1-HA, of inactive AMPKαK45R (AMPKα1K45R+AMPKβ1-Flag+AMPKγ1-HA or of constitutively active AMPKγR70Q (AMPKα1-HA+AMPKβ1-Flag+AMPKγ1R70Q. NaPi-IIa activity was estimated from phosphate-induced current in dual electrode voltage clamp experiments. Results: In NaPi-IIa-expressing, but not in water-injected Xenopus oocytes, the addition of phosphate (1 mM to the extracellular bath solution generated a current (Ip, which was significantly decreased by coexpression of wild-type AMPK and of AMPKγR70Q but not of AMPKαK45R. The phosphate-induced current in NaPi-IIa- and AMPK-expressing Xenopus ooocytes was significantly increased by AMPK inhibitor Compound C (20 µM. Kinetic analysis revealed that AMPK significantly decreased the maximal transport rate. Conclusion: The AMP-activated protein kinase AMPK is a powerful regulator of NaPi-IIa and thus of renal tubular phosphate transport.

  13. The Marine Biogeochemistry of Zinc Isotopes

    Science.gov (United States)

    2007-06-01

    dust (Niger) Sapropel (Mediterranean) 4* Deep-Sea Sediments * • Lobster Liver Mussel tissue Plankton Zooplankton Zinc ores * * * Sediment trap material...of natural plankton over large changes in nutrient concentrations in the Peru Upwelling Region. This suggests either that the isotope effect for Zn...hydrothermal fluids and minerals, cultured marine phytoplankton, natural plankton , and seawater. By measuring Zn isotopes in a diverse array of

  14. IUPAC Periodic Table of the Isotopes

    Science.gov (United States)

    Holden, N.E.; Coplen, T.B.; Böhlke, J.K.; Wieser, M.E.; Singleton, G.; Walczyk, T.; Yoneda, S.; Mahaffy, P.G.; Tarbox, L.V.

    2011-01-01

    For almost 150 years, the Periodic Table of the Elements has served as a guide to the world of elements by highlighting similarities and differences in atomic structure and chemical properties. To introduce students, teachers, and society to the existence and importance of isotopes of the chemical elements, an IUPAC Periodic Table of the Isotopes (IPTI) has been prepared and can be found as a supplement to this issue.

  15. Magnesium isotope geochemistry in arc volcanism

    Science.gov (United States)

    Teng, Fang-Zhen; Hu, Yan

    2016-01-01

    Incorporation of subducted slab in arc volcanism plays an important role in producing the geochemical and isotopic variations in arc lavas. The mechanism and process by which the slab materials are incorporated, however, are still uncertain. Here, we report, to our knowledge, the first set of Mg isotopic data for a suite of arc lava samples from Martinique Island in the Lesser Antilles arc, which displays one of the most extreme geochemical and isotopic ranges, although the origin of this variability is still highly debated. We find the δ26Mg of the Martinique Island lavas varies from −0.25 to −0.10, in contrast to the narrow range that characterizes the mantle (−0.25 ± 0.04, 2 SD). These high δ26Mg values suggest the incorporation of isotopically heavy Mg from the subducted slab. The large contrast in MgO content between peridotite, basalt, and sediment makes direct mixing between sediment and peridotite, or assimilation by arc crust sediment, unlikely to be the main mechanism to modify Mg isotopes. Instead, the heavy Mg isotopic signature of the Martinique arc lavas requires that the overall composition of the mantle wedge is buffered and modified by the preferential addition of heavy Mg isotopes from fluids released from the altered subducted slab during fluid−mantle interaction. This, in turn, suggests transfer of a large amount of fluid-mobile elements from the subducting slab to the mantle wedge and makes Mg isotopes an excellent tracer of deep fluid migration. PMID:27303032

  16. The Facility for Rare Isotope Beams

    OpenAIRE

    Wrede C.

    2015-01-01

    The Facility for Rare Isotope Beams (FRIB) is a United States Department of Energy user facility currently under construction on the campus of Michigan State University. Based on a 400 kW, 200 MeV/u heavy-ion driver linac, FRIB will deliver high-quality fast, thermalized, and re-accelerated beams of rare isotopes with unprecedented intensities to a variety of experimental areas and equipment. New science opportunities at the frontiers of nuclear structure, nuclear astrophysics, fundamental sy...

  17. Dye laser chain for laser isotope separation

    Science.gov (United States)

    Doizi, Denis; Jaraudias, Jean; Pochon, E.; Salvetat, G.

    1993-05-01

    Uranium enrichment by laser isotope separation uses a three step operation which requires four visible wavelengths to boost an individual U235 isotope from a low lying atomic energy level to an autoionizing state. The visible wavelengths are delivered by dye lasers pumped by copper vapor lasers (CVL). In this particular talk, a single dye chain consisting of a master oscillator and amplifier stages will be described and some of its performance given.

  18. Surfaces that become isotopic after Dehn filling

    CERN Document Server

    Bachman, David; Sedgwick, Eric

    2010-01-01

    We show that after generic filling along a torus boundary component of a 3-manifold, no two closed, 2-sided, essential surfaces become isotopic, and no closed, 2-sided, essential surface becomes inessential. That is, the set of essential surfaces (considered up to isotopy) survives unchanged in all suitably generic Dehn fillings. Furthermore, for all but finitely many non-generic fillings, we show that two essential surfaces can only become isotopic in a constrained way.

  19. Hydrogen isotope effect on the Dimits shift

    Science.gov (United States)

    Itoh, S.-I.; Itoh, K.

    2016-10-01

    The hydrogen isotope effect on the Dimits shift in drift wave turbulence (Dimits et al 2000 Phys. Plasmas 7 969) is discussed using the theory of zonal flows, in which the nonlinear damping rate of zonal flows is taken into account. The up-shift of the critical linear growth rate of the drift waves, above which drift wave fluctuations develop, is investigated. The dependence on the mass number of the hydrogen isotope is discussed.

  20. Nickel isotopic composition of the mantle

    Science.gov (United States)

    Gall, Louise; Williams, Helen M.; Halliday, Alex N.; Kerr, Andrew C.

    2017-02-01

    This paper presents a detailed high-precision study of Ni isotope variations in mantle peridotites and their minerals, komatiites as well as chondritic and iron meteorites. Ultramafic rocks display a relatively large range in δ60 Ni (permil deviation in 60 Ni /58 Ni relative to the NIST SRM 986 Ni isotope standard) for this environment, from 0.15 ± 0.07‰ to 0.36 ± 0.08‰, with olivine-rich rocks such as dunite and olivine cumulates showing lighter isotope compositions than komatiite, lherzolite and pyroxenite samples. The data for the mineral separates shed light on the origin of these variations. Olivine and orthopyroxene display light δ60 Ni whereas clinopyroxene and garnet are isotopically heavy. This indicates that peridotite whole-rock δ60 Ni may be controlled by variations in modal mineralogy, with the prediction that mantle melts will display variable δ60 Ni values due to variations in residual mantle and cumulate mineralogy. Based on fertile peridotite xenoliths and Phanerozoic komatiite samples it is concluded that the upper mantle has a relatively homogeneous Ni isotope composition, with the best estimate of δ60Nimantle being 0.23 ± 0.06‰ (2 s.d.). Given that >99% of the Ni in the silicate Earth is located in the mantle, this also defines the Ni isotope composition of the Bulk Silicate Earth (BSE). This value is nearly identical to the results obtained for a suite of chondrites and iron meteorites (mean δ60 Ni 0.26 ± 0.12‰ and 0.29 ± 0.10‰, respectively) showing that the BSE is chondritic with respect to its Ni isotope composition, with little to no Ni mass-dependent isotope fractionation resulting from core formation.

  1. Mixed Population Screening for Sulfur Isotopes

    Institute of Scientific and Technical Information of China (English)

    CUI Bin; ZHAO Lei; ZHAN Zhaoyang; HE Zhijun

    2004-01-01

    Quantitative research of the origin of sulfur isotopes is a difficult problem that has puzzled geochemists all along. In the study of the middle and lower reaches of the Yangtze River and the Dongpo orefield in Hunan Province,the authors successfully applied the mathematical model of mixed population screening to quantitatively resolving the problem on the origin of sulfur isotopes, which is significant in finding out the source of mineralizing matter and metallogenic mechanisms.

  2. IBFM for Ba isotopes and chaoticity

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D.; Cata-Danil, G.; Ivascu, M.; Ur, C.A. (Inst. of Atomic Physics, Bucharest (Romania)); Gizon, A.; Gizon, J. (Inst. des Sciences Nucleaires, 38 - Grenoble (France))

    1992-08-01

    Fluctuation properties have been analysed for the energy levels predicted by IBFM calculations in the Ba isotopes {sup 121}Ba to {sup 131}Ba. The results indicate, in general, a situation which is close to the chaotic limit. For the lighter isotopes studied (121 and 123), a phase transition is obtained in the low-spin, positive parity states, from a situation close to regularity at low excitation energies, towards chaoticity at higher excitations. (orig.).

  3. IBFM for barium isotopes and chaoticity

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D.; Cata-Danil, G.; Ivascu, M.; Ur, C.A. (Institute of Atomic Physics, Bucharest (Romania)); Gizon, A.; Gizon, J. (Institute des Sciences Nucleaires, Grenoble (France))

    1992-01-01

    Fluctuation properties have been analysed for the energy levels predicted by IBFM calculations in the Ba isotopes {sup 121}Ba to {sup 131}Ba. The results are indicating, in general, a situation which is close to the chaotic limit. For the lighter isotopes studied (121 and 131), a phase transition is obtained in the low-spin, positive states, from a situation close to regularity at low excitation energies, towards chaoticity at higher excitations. (author).

  4. IBFM for barium isotopes and chaoticity

    Science.gov (United States)

    Bucurescu, D.; Cata-Danil, G.; Ivascu, M.; Gizon, A.; Gizon, J.; UR, C. A.

    Fluctuation properties have been analysed for the energy levels predicted by IBFM calculations in the Ba isotopes 121Ba to 131Ba. The results are indicating, in general, a situation which is close to the chaotic limit. For the lighter isotopes studied (121 and 131), a phase transition is obtained in the low-spin, positive states, from a situation close to regularity at low excitation energies, towards chaoticity at higher excitations.

  5. Isotope shortage triggers delays for patients

    Science.gov (United States)

    Gould, Paula

    2009-07-01

    An unplanned shutdown of a nuclear reactor in Canada is disrupting the supply of medical isotopes across North America and forcing some hospitals to cancel or postpone patients' tests. The closure of the National Research Universal (NRU) reactor in Chalk River, Ontario, has also embarrassed Canadian officials, including a senior government minister who was forced to apologize after calling the isotope shortage a "sexy" career challenge.

  6. Isotopic discrimination of zinc in higher plants.

    Science.gov (United States)

    Weiss, D J; Mason, T F D; Zhao, F J; Kirk, G J D; Coles, B J; Horstwood, M S A

    2005-03-01

    * The extent of isotopic discrimination of transition metals in biological processes is poorly understood but potentially has important applications in plant and biogeochemical studies. * Using multicollector inductively coupled plasma (ICP) mass spectrometry, we measured isotopic fractionation of zinc (Zn) during uptake from nutrient solutions by rice (Oryza sativa), lettuce (Lactuca sativa) and tomato (Lycopersicon esculentum) plants. * For all three species, the roots showed a similar extent of heavy Zn enrichment relative to the nutrient solution, probably reflecting preferential adsorption on external root surfaces. By contrast, a plant-species specific enrichment of the light Zn isotope occurred in the shoots, indicative of a biological, membrane-transport controlled uptake into plant cells. The extent of the fractionation in the shoots further depended on the Zn speciation in the nutrient solution. * The observed isotopic depletion in heavy Zn from root to shoot (-0.13 to -0.26 per atomic mass unit) is equivalent to roughly a quarter of the total reported terrestrial variability of Zn isotopic compositions (c. 0.84 per atomic mass unit). Plant uptake therefore represents an important source of isotopic variation in biogeochemical cycling of Zn.

  7. Iron isotopic fractionation during continental weathering

    Energy Technology Data Exchange (ETDEWEB)

    Fantle, Matthew S.; DePaolo, Donald J.

    2003-10-01

    The biological activity on continents and the oxygen content of the atmosphere determine the chemical pathways through which Fe is processed at the Earth's surface. Experiments have shown that the relevant chemical pathways fractionate Fe isotopes. Measurements of soils, streams, and deep-sea clay indicate that the {sup 56}Fe/{sup 54}Fe ratio ({delta}{sup 56}Fe relative to igneous rocks) varies from +1{per_thousand} for weathering residues like soils and clays, to -3{per_thousand} for dissolved Fe in streams. These measurements confirm that weathering processes produce substantial fractionation of Fe isotopes in the modern oxidizing Earth surface environment. The results imply that biologically-mediated processes, which preferentially mobilize light Fe isotopes, are critical to Fe chemistry in weathering environments, and that the {delta}{sup 56}Fe of marine dissolved Fe should be variable and negative. Diagenetic reduction of Fe in marine sediments may also be a significant component of the global Fe isotope cycle. Iron isotopes provide a tracer for the influence of biological activity and oxygen in weathering processes through Earth history. Iron isotopic fractionation during weathering may have been smaller or absent in an oxygen-poor environment such as that of the early Precambrian Earth.

  8. The discovery of isotopes a complete compilation

    CERN Document Server

    Thoennessen, Michael

    2016-01-01

    This book describes the exciting discovery of every isotope observed on earth to date, which currently numbers some 3000. For each isotope a short essay highlights the authors of the first publication for the isotope, the laboratory and year where and when the isotope was discovered, as well as details about the production and detection methods used. In controversial cases previously claims are also discussed. At the end a comprehensive table lists all isotopes sorted by elements and a complete list of references. Preliminary versions of these paragraphs have been published over the last few years as separate articles in the journal "Atomic Data and Nuclear Data Tables". The work re-evaluates all assignments judging them with a uniform set of criteria. In addition, the author includes over 100 new isotopes which have been discovered since the articles published. This book is a source of information for researchers as well as enthusiastic laymen alike. From the prepublication review: “The explanations focus ...

  9. Laser Spectroscopy of Neutron Rich Bismuth Isotopes

    CERN Multimedia

    2002-01-01

    %IS344 :\\\\ \\\\ The aim of the experiment is to measure the optical isotope shifts and hyperfine structures of bismuth isotopes across the N=126 shell closure in order to extract the change in mean square charge radii ($\\delta\\langle r^{2}\\rangle$) and static moments. These include the first isotones of lead to be measured directly above the shell closure and will provide new information on the systematics of the kink ($\\delta\\langle r^{2}\\rangle)$ seen in the lead isotopic chain. After two very successful runs the programme has been extended to include the neutron deficient isotopes below $^{201}$Bi to study the systematics across the $i_{13/2}$ neutron sub-shell closure at N=118.\\\\ \\\\ During the initial 2 runs (9 shifts) the isotope shifts and hyperfine structures of three new isotopes, $ ^{210,212,213}$Bi and the 9$^{-}$ isomer of $^{210}$Bi have been measured. The accuracy of the previous measurements of $^{205,206,208}$Bi have been greatly improved. The samples of $ ^{208,210,210^{m}}$Bi were prepared by c...

  10. Identification of isotopically primitive interplanetary dust particles: A NanoSIMS isotopic imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Floss, C; Stadermann, F J; Bradley, J P; Dai, Z R; Bajt, S; Graham, G; Lea, A S

    2005-09-02

    We have carried out a comprehensive survey of the isotopic compositions (H, B, C, N, O, S) of a suite of interplanetary dust particles (IDPs), including both cluster and individual particles. Isotopic imaging with the NanoSIMS shows the presence of numerous discrete hotspots that are strongly enriched in {sup 15}N, including the largest {sup 15}N enrichments ({approx}1300 {per_thousand}) observed in IDPs to date. A number of the IDPs also contain larger regions with more modest enrichments in {sup 15}N, leading to average bulk N isotopic compositions that are {sup 15}N-enriched in these IDPs. Although C isotopic compositions are normal in most of the IDPs, two {sup 15}N-rich N-hotspots have correlated {sup 13}C anomalies. CN{sup -}/C{sup -} ratios suggest that most of the {sup 15}N-rich hotspots are associated with relatively N-poor carbonaceous matter, although specific carriers have not been determined. H isotopic distributions are similar to those of N: D anomalies are present both as distinct very D-rich hotspots and as larger regions with more modest enrichments. Nevertheless, H and N isotopic anomalies are not directly correlated, consistent with results from previous studies. Oxygen isotopic imaging shows the presence of abundant presolar silicate grains in the IDPs. The O isotopic compositions of the grains are similar to those found in presolar oxide and silicate grains from primitive meteorites. Most of the silicate grains in the IDPs have isotopic ratios consistent with meteoritic Group 1 oxide grains, indicating origins in oxygen-rich red giant and asymptotic giant branch stars, but several presolar silicates exhibit the {sup 17}O and {sup 18}O enrichments of Group 4 oxide grains, whose origin is less well understood. Based on their N isotopic compositions, the IDPs studied here can be divided into two groups. One group is characterized as being ''isotopically primitive'' and consists of those IDPs that have anomalous bulk N isotopic

  11. Morphological, Physiological, and Structural Responses of Two Species of Artemisia to NaCl Stress

    Directory of Open Access Journals (Sweden)

    Zhi-Yong Guan

    2013-01-01

    Full Text Available Effects of salt stress on Artemisia scoparia and A. vulgaris “Variegate” were examined. A. scoparia leaves became withered under NaCl treatment, whereas A. vulgaris “Variegate” leaves were not remarkably affected. Chlorophyll content decreased in both species, with a higher reduction in A. scoparia. Contents of proline, MDA, soluble carbohydrate, and Na+ increased in both species under salt stress, but A. vulgaris “Variegate” had higher level of proline and soluble carbohydrate and lower level of MDA and Na+. The ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ in A. vulgaris “Variegate” under NaCl stress were higher. Moreover, A. vulgaris “Variegate” had higher transport selectivity of K+/Na+ from root to stem, stem to middle mature leaves, and upper newly developed leaves than A. scoparia under NaCl stress. A. vulgaris “Variegate” chloroplast maintained its morphological integrity under NaCl stress, whereas A. scoparia chloroplast lost integrity. The results indicated that A. scoparia is more sensitive to salt stress than A. vulgaris “Variegate.” Salt tolerance is mainly related to the ability of regulating osmotic pressure through the accumulation of soluble carbohydrates and proline, and the gradient distribution of K+ between roots and leaves was also contributed to osmotic pressure adjustment and improvement of plant salt tolerance.

  12. KIPS kilowatt isotope power system

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    This Control System topical report covers basic control requirements, selection of control system and a recent review of an electromechanical approach to the flow control valve. Section I covers the basic control requirements for Organic Rankine cycle systems, particular requirements for an isotope fueled space power system, and special requirements imposed by launch, Shuttle deployment and spacecraft requirements. Various control devices which can be used to meet system requirements are discussed. In Section II, various combinations of control functions and devices are presented with comments as to the suitability of each for the intended application. This is essentially a review of the selection process used to pick the present KIPS control system. The formal trade-off matrix, component description, and system selection, as prepared for Design Reviews 2 and 3, is included as Appendix A to the report. Section 3 covers the recently completed design of an electronic-electromechanical flow control valve and compares this approach to the thermal bulb-hydro-mechanical flow control valve baseline. The results of this comparative study indicate that the present configuration is preferable to an electrical valve.

  13. Fumarate reductase activity maintains an energized membrane in anaerobic Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Shinya Watanabe

    2011-10-01

    Full Text Available Oxygen depletion of Mycobacterium tuberculosis engages the DosR regulon that coordinates an overall down-regulation of metabolism while up-regulating specific genes involved in respiration and central metabolism. We have developed a chemostat model of M. tuberculosis where growth rate was a function of dissolved oxygen concentration to analyze metabolic adaptation to hypoxia. A drop in dissolved oxygen concentration from 50 mmHg to 0.42 mmHg led to a 2.3 fold decrease in intracellular ATP levels with an almost 70-fold increase in the ratio of NADH/NAD(+. This suggests that re-oxidation of this co-factor becomes limiting in the absence of a terminal electron acceptor. Upon oxygen limitation genes involved in the reverse TCA cycle were upregulated and this upregulation was associated with a significant accumulation of succinate in the extracellular milieu. We confirmed that this succinate was produced by a reversal of the TCA cycle towards the non-oxidative direction with net CO(2 incorporation by analysis of the isotopomers of secreted succinate after feeding stable isotope ((13C labeled precursors. This showed that the resulting succinate retained both carbons lost during oxidative operation of the TCA cycle. Metabolomic analyses of all glycolytic and TCA cycle intermediates from (13C-glucose fed cells under aerobic and anaerobic conditions showed a clear reversal of isotope labeling patterns accompanying the switch from normoxic to anoxic conditions. M. tuberculosis encodes three potential succinate-producing enzymes including a canonical fumarate reductase which was highly upregulated under hypoxia. Knockout of frd, however, failed to reduce succinate accumulation and gene expression studies revealed a compensatory upregulation of two homologous enzymes. These major realignments of central metabolism are consistent with a model of oxygen-induced stasis in which an energized membrane is maintained by coupling the reductive branch of the TCA

  14. Finding Control Cases and Maintaining Immersion: Challenges and Opportunities.

    Science.gov (United States)

    Ehrlich, Lena Theodorou

    2016-10-03

    Given that surveys, as well as frequent observations by institute faculty, indicate that many candidates have difficulty finding control cases and maintaining immersion and that many graduate analysts face similar challenges, it would seem that psychoanalytic training does not prepare candidates adequately for finding patients and practicing analysis while in training and, for many, after they have graduated. Although external challenges are formidable, it is by identifying and making use of internal challenges to finding cases that candidates can develop an analytic mind: the identity, approach, and skills necessary not only to graduate but to have the choice to practice clinical psychoanalysis post-graduation. Some of the internal challenges and their manifestations in different phases of initiating analysis (referrals, initial consultation, recommendation) are discussed and two detailed examples are offered to illustrate the productive use of candidates' countertransferences in finding cases and maintaining immersion. Finally, recommendations for institutional solutions are provided. © 2016 by the American Psychoanalytic Association.

  15. Creating and maintaining chemical artificial life by robotic symbiosis

    DEFF Research Database (Denmark)

    Hanczyc, Martin M.; Parrilla, Juan M.; Nicholson, Arwen

    2015-01-01

    We present a robotic platform based on the open source RepRap 3D printer that can print and maintain chemical artificial life in the form of a dynamic, chemical droplet. The robot uses computer vision, a self-organizing map, and a learning program to automatically categorize the behavior of the d...... confluence of chemical, artificial intelligence, and robotic approaches to artificial life.......We present a robotic platform based on the open source RepRap 3D printer that can print and maintain chemical artificial life in the form of a dynamic, chemical droplet. The robot uses computer vision, a self-organizing map, and a learning program to automatically categorize the behavior...

  16. Application of Ultrasonic Waves on Maintaining Freshness of Tilapia Fillet

    Directory of Open Access Journals (Sweden)

    Ruddy Suwandi

    2015-06-01

    Full Text Available ish fillet is one of fisheries products that easily deteriorated; hence handling techniques are needed to maintain the freshness. Ultrasonic wave have been widely applied to some of food products for maintaining freshness through microbial inactivation, however the ultrasonic application to fisheries products has not been reported. The purpose of this study was to analyze the effect of ultrasonic wave on fish freshness. The stages of the study were sample preparation, sonication, freshness parameters examination and histology observation. Ultrasonic wave did not affectthe organoleptic value and the TVB, but affected the pH value and the TPC. The sample in which the TPC value was found significantly different, were further observed after 48 and 96 hours storage. The result showed that the TPC value of sonicated sample for 9 minutes was lower to that of without sonication. Histology analysis showed, however, sonication made the structure of muscle fiber less compact and deformation of myomer was found.

  17. Motility and peristaltic flow in maintaining microbiome populations

    Science.gov (United States)

    Mirbagheri, Seyed Amir; Fu, Henry C.

    2016-11-01

    Bacteria are an important component of the microbiome in the digestive tract, and must be able to maintain their population despite the fact that the contents of the intestines are constantly flowing towards evacuation. Many bacteria accomplish this by colonizing the surfaces of the intestines where flows diminish, but some species live in the lumen. We attempt to address whether swimming motility of these species plays an important role in maintaining bacterial population in the face of peristaltic pumping out of the intestine. Using a two-dimensional model of peristaltic flows induced by small-amplitude traveling waves we examine the Lagrangian trajectories of passive bacteria as well as motile bacteria, which are treated as Brownian particles undergoing enhanced diffusion due to the bacteria's run-and-tumble motility. We examine how the densities of growing populations of bacteria depend on the combination of motility and peristaltic flow.

  18. Creating and maintaining chemical artificial life by robotic symbiosis

    DEFF Research Database (Denmark)

    Hanczyc, Martin M.; Parrilla, Juan M.; Nicholson, Arwen

    2015-01-01

    We present a robotic platform based on the open source RepRap 3D printer that can print and maintain chemical artificial life in the form of a dynamic, chemical droplet. The robot uses computer vision, a self-organizing map, and a learning program to automatically categorize the behavior of the d...... confluence of chemical, artificial intelligence, and robotic approaches to artificial life.......We present a robotic platform based on the open source RepRap 3D printer that can print and maintain chemical artificial life in the form of a dynamic, chemical droplet. The robot uses computer vision, a self-organizing map, and a learning program to automatically categorize the behavior...

  19. An intervention to help older adults maintain independence safely.

    Science.gov (United States)

    Ganong, Lawrence H; Coleman, Marilyn; Benson, Jacquelyn J; Snyder-Rivas, Linley A; Stowe, James D; Porter, Eileen J

    2013-05-01

    Older adults who live alone are at risk for problems (e.g., falling, sudden illness). To maintain themselves safely at home they may benefit from planning to prevent problems. The purpose of this study was to evaluate an intervention designed to train family members or friends as to how to help older adults who were living alone make plans to maintain independence safely in their homes and to make behavioral and household changes to enhance safety. Support network members of 19 older adults randomly assigned to the intervention group were taught to use multiple segment vignettes to assist the older adults in creating plans for living safely. Older adults in the control group (n = 21) were asked to engage in an unstructured discussion about home safety with their network members. Older adults in the intervention group developed safer plans and made more household and behavioral changes than did control group adults.

  20. Maintaining dignity. The perspective of nursing home residents

    DEFF Research Database (Denmark)

    Høy, Bente

    2014-01-01

    Purpose. The overall purpose of this cross-country Nordic study was to gain further knowledge about dignity in nursing homes and the circumstances which may have an impact on it. The aim of this part of the study is to present the results, exploring nursing home residents’ experiences on how...... dignity is maintained. Background. Elderly living in nursing homes are vulnerable which appeal to nursing care ethics and emphasise the importance of care for human dignity. There have been several attempts to define dignity as a theoretical concept, but few studies on how dignity is maintained from...... the perspective of the nursing home residents. Method. This qualitative study has an explorative design, based on qualitative individual research interviews. Twenty-eight nursing home residents were included from six nursing homes in Scandi-navia. A phenomenological-hermeneutic approach, inspired by Ricoeur...