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Sample records for short lived isotopes

  1. Manipulating Short-Lived Isotopes with Inhomogeneous RF-Fields

    SciTech Connect

    Li, T.; Schuessler, H.A.

    2003-08-26

    Online isotopes separators (ISOL-systems) and projectile fragment separators provide a wide variety of radioactive ions with energies in the keV to the several MeV ranges. For high resolution radio frequency and optical spectroscopy the ions must be decelerated to low energies and possibly injected into an ion trap. With this goal in mind we have made simulations of ion orbits under the influence of strong focusing by inhomogeneous RF fields and decelerating DC fields. The operation of the segmented linear ion guide, the ion carpet, and the ion funnel are discussed. The optimum operating parameters of these devices are obtained using computer simulations with SIMION software.

  2. Accurate mass measurements of short-lived isotopes with the MISTRAL* rf spectrometer

    SciTech Connect

    Toader, C.; Audi, G.; Doubre, H.; Jacotin, M.; Henry, S.; Kepinski, J.-F.; Le Scornet, G.; Lunney, D.; Monsanglant, C.; Saint Simon, M. de; Thibault, C.; Borcea, C.; Duma, M.; Lebee, G.

    1999-01-15

    The MISTRAL* experiment has measured its first masses at ISOLDE. Installed in May 1997, this radiofrequency transmission spectrometer is to concentrate on nuclides with particularly short half-lives. MISTRAL received its first stable beam in October and first radioactive beam in November 1997. These first tests, with a plasma ion source, resulted in excellent isobaric separation and reasonable transmission. Further testing and development enabled first data taking in July 1998 on neutron-rich Na isotopes having half-lives as short as 31 ms.

  3. Accurate mass determination of short-lived isotopes by a tandem Penning-trap mass spectrometer

    SciTech Connect

    Stolzenberg, H.; Becker, S.; Bollen, G.; Kern, F.; Kluge, H.; Otto, T.; Savard, G.; Schweikhard, L. ); Audi, G. ); Moore, R.B. ); The ISOLDE Collaboration

    1990-12-17

    A mass spectrometer consisting of two Penning traps has been set up for short-lived isotopes at the on-line mass separator ISOLDE at CERN. The ion beam is collected and cooled in the first trap. After delivery to the second trap, high-accuracy direct mass measurements are made by determining the cyclotron frequency of the stored ions. Measurements have been performed for {sup 118}Cs--{sup 137}Cs. A resolving power of over 10{sup 6} and an accuracy of 1.4{times}10{sup {minus}7} have been achieved, corresponding to about 20 keV.

  4. New Short-Lived Isotope ^{221}U and the Mass Surface Near N=126.

    PubMed

    Khuyagbaatar, J; Yakushev, A; Düllmann, Ch E; Ackermann, D; Andersson, L-L; Block, M; Brand, H; Cox, D M; Even, J; Forsberg, U; Golubev, P; Hartmann, W; Herzberg, R-D; Heßberger, F P; Hoffmann, J; Hübner, A; Jäger, E; Jeppsson, J; Kindler, B; Kratz, J V; Krier, J; Kurz, N; Lommel, B; Maiti, M; Minami, S; Mistry, A K; Mrosek, Ch M; Pysmenetska, I; Rudolph, D; Sarmiento, L G; Schaffner, H; Schädel, M; Schausten, B; Steiner, J; De Heidenreich, T Torres; Uusitalo, J; Wegrzecki, M; Wiehl, N; Yakusheva, V

    2015-12-11

    Two short-lived isotopes ^{221}U and ^{222}U were produced as evaporation residues in the fusion reaction ^{50}Ti+^{176}Yb at the gas-filled recoil separator TASCA. An α decay with an energy of E_{α}=9.31(5)  MeV and half-life T_{1/2}=4.7(7)  μs was attributed to ^{222}U. The new isotope ^{221}U was identified in α-decay chains starting with E_{α}=9.71(5)  MeV and T_{1/2}=0.66(14)  μs leading to known daughters. Synthesis and detection of these unstable heavy nuclei and their descendants were achieved thanks to a fast data readout system. The evolution of the N=126 shell closure and its influence on the stability of uranium isotopes are discussed within the framework of α-decay reduced width. PMID:26705628

  5. MIXING AND TRANSPORT OF SHORT-LIVED AND STABLE ISOTOPES AND REFRACTORY GRAINS IN PROTOPLANETARY DISKS

    SciTech Connect

    Boss, Alan P.

    2013-08-10

    Analyses of primitive meteorites and cometary samples have shown that the solar nebula must have experienced a phase of large-scale outward transport of small refractory grains as well as homogenization of initially spatially heterogeneous short-lived isotopes. The stable oxygen isotopes, however, were able to remain spatially heterogeneous at the {approx}6% level. One promising mechanism for achieving these disparate goals is the mixing and transport associated with a marginally gravitationally unstable (MGU) disk, a likely cause of FU Orionis events in young low-mass stars. Several new sets of MGU models are presented that explore mixing and transport in disks with varied masses (0.016 to 0.13 M{sub Sun }) around stars with varied masses (0.1 to 1 M{sub Sun }) and varied initial Q stability minima (1.8 to 3.1). The results show that MGU disks are able to rapidly (within {approx}10{sup 4} yr) achieve large-scale transport and homogenization of initially spatially heterogeneous distributions of disk grains or gas. In addition, the models show that while single-shot injection heterogeneity is reduced to a relatively low level ({approx}1%), as required for early solar system chronometry, continuous injection of the sort associated with the generation of stable oxygen isotope fractionations by UV photolysis leads to a sustained, relatively high level ({approx}10%) of heterogeneity, in agreement with the oxygen isotope data. These models support the suggestion that the protosun may have experienced at least one FU Orionis-like outburst, which produced several of the signatures left behind in primitive chondrites and comets.

  6. Short-lived Isotopes from a Close-by AGB Star Triggering the Protosolar Nebula

    NASA Astrophysics Data System (ADS)

    Gallino, R.; Busso, M.; Wasserburg, G. J.; Straniero, O.

    The presence of short-lived isotopes in the early solar system, in particular 26Al, 41Ca, 60Fe, and 107Pd, point to a close-by and fresh nucleosynthesis source, possibly triggering the collapse of the protosolar nebula. We present the results of nucleosynthesis calculations based on an AGB polluting hypothesis. A general concordance of the predicted yields of the above radioactivities relative to 26Al can be obtained in the case of an intermediate mass AGB star with hot bottom burning in the envelope (thus producing 26Al), and mixing through a series of third dredge-up episodes a fraction of the C-rich and s-processed material from the He intershell with the extended envelope. Polution of the protosolar nebula with freshly synthesized material may derive from the efficient winds of the AGB star. In AGB stars, the s-process nucleosynthesis occurs both during the maximum phase of every thermal runaway, driven by the partial activation of the 22Ne(alpha,n)25Mg reaction, and in the interpulse phase, where the 13C nuclei are fully consumed in radiative conditions by the activation of the 13C(alpha,n)16O reaction. We have used different prescriptions for the amount of the 13C nuclei present in the intershell. A minimum amount of 13C is naturally expected in the ashes of H-shell burning. Possible formation of an extra "13C-pocket" derives from the injection of a small amount of protons from the envelope into the 12C-rich intershell during any third dredge-up episode, when the H-shell is inactivated. Prediction for other short-lived, 36Cl, 135Cs, and 205Pb, are given. General consequences for the pollution of the protosolar nebula with newly synthesized stable isotopes from the AGB winds are outlined. The origin of other detected short-lived nuclei, in particular 53Mn, 129I, and 182Hf, which cannot come from an AGB source, is analysed. The alternative trigger hypothesis by a close-by Supernova is discussed.

  7. Human neutrophil kinetics: modeling of stable isotope labeling data supports short blood neutrophil half-lives.

    PubMed

    Lahoz-Beneytez, Julio; Elemans, Marjet; Zhang, Yan; Ahmed, Raya; Salam, Arafa; Block, Michael; Niederalt, Christoph; Asquith, Becca; Macallan, Derek

    2016-06-30

    Human neutrophils have traditionally been thought to have a short half-life in blood; estimates vary from 4 to 18 hours. This dogma was recently challenged by stable isotope labeling studies with heavy water, which yielded estimates in excess of 3 days. To investigate this disparity, we generated new stable isotope labeling data in healthy adult subjects using both heavy water (n = 4) and deuterium-labeled glucose (n = 9), a compound with more rapid labeling kinetics. To interpret results, we developed a novel mechanistic model and applied it to previously published (n = 5) and newly generated data. We initially constrained the ratio of the blood neutrophil pool to the marrow precursor pool (ratio = 0.26; from published values). Analysis of heavy water data sets yielded turnover rates consistent with a short blood half-life, but parameters, particularly marrow transit time, were poorly defined. Analysis of glucose-labeling data yielded more precise estimates of half-life (0.79 ± 0.25 days; 19 hours) and marrow transit time (5.80 ± 0.42 days). Substitution of this marrow transit time in the heavy water analysis gave a better-defined blood half-life of 0.77 ± 0.14 days (18.5 hours), close to glucose-derived values. Allowing the ratio of blood neutrophils to mitotic neutrophil precursors (R) to vary yielded a best-fit value of 0.19. Reanalysis of the previously published model and data also revealed the origin of their long estimates for neutrophil half-life: an implicit assumption that R is very large, which is physiologically untenable. We conclude that stable isotope labeling in healthy humans is consistent with a blood neutrophil half-life of less than 1 day. PMID:27136946

  8. Human neutrophil kinetics: modeling of stable isotope labeling data supports short blood neutrophil half-lives

    PubMed Central

    Lahoz-Beneytez, Julio; Elemans, Marjet; Zhang, Yan; Ahmed, Raya; Salam, Arafa; Block, Michael; Niederalt, Christoph; Macallan, Derek

    2016-01-01

    Human neutrophils have traditionally been thought to have a short half-life in blood; estimates vary from 4 to 18 hours. This dogma was recently challenged by stable isotope labeling studies with heavy water, which yielded estimates in excess of 3 days. To investigate this disparity, we generated new stable isotope labeling data in healthy adult subjects using both heavy water (n = 4) and deuterium-labeled glucose (n = 9), a compound with more rapid labeling kinetics. To interpret results, we developed a novel mechanistic model and applied it to previously published (n = 5) and newly generated data. We initially constrained the ratio of the blood neutrophil pool to the marrow precursor pool (ratio = 0.26; from published values). Analysis of heavy water data sets yielded turnover rates consistent with a short blood half-life, but parameters, particularly marrow transit time, were poorly defined. Analysis of glucose-labeling data yielded more precise estimates of half-life (0.79 ± 0.25 days; 19 hours) and marrow transit time (5.80 ± 0.42 days). Substitution of this marrow transit time in the heavy water analysis gave a better-defined blood half-life of 0.77 ± 0.14 days (18.5 hours), close to glucose-derived values. Allowing the ratio of blood neutrophils to mitotic neutrophil precursors (R) to vary yielded a best-fit value of 0.19. Reanalysis of the previously published model and data also revealed the origin of their long estimates for neutrophil half-life: an implicit assumption that R is very large, which is physiologically untenable. We conclude that stable isotope labeling in healthy humans is consistent with a blood neutrophil half-life of less than 1 day. PMID:27136946

  9. ON THE INJECTION OF SHORT-LIVED RADIONUCLIDES FROM A SUPERNOVA INTO THE SOLAR NEBULA: CONSTRAINTS FROM THE OXYGEN ISOTOPES

    SciTech Connect

    Liu, Ming-Chang

    2014-02-01

    Injection of short-lived radionuclides from a nearby core-collapse Type II supernova into the already-formed solar protoplanetary disk was proposed to account for the former presence of {sup 26}Al, {sup 41}Ca, and {sup 60}Fe in the early solar system inferred from isotopic analysis of meteoritic samples. One potential corollary of this ''late-injection'' scenario is that the disk's initial (pre-injection) oxygen isotopic composition could be significantly altered, as supernova material that carried the short-lived radionuclides would also deliver oxygen components synthesized in that given star. Therefore, the change in the oxygen isotopic composition of the disk caused by injection could in principle be used to constrain the supernova injection models. Previous studies showed that although supernova oxygen could result in a wide range of shifts in {sup 17}O/{sup 16}O and {sup 18}O/{sup 16}O of the disk, a couple of cases existed where the calculated oxygen changes in the disk would be compatible with the meteoritic and solar wind data. Recently, the initial abundances of {sup 41}Ca and {sup 60}Fe in the solar system were revised to lower values, and the feasibility of supernova injection as a source for the three radionuclides was called into question. In this study, supernova parameters needed for matching {sup 26}Al, {sup 41}Ca, and {sup 60}Fe to their early solar system abundances were reinvestigated and then were used to infer the pre-injection O-isotope composition of the disk. The result suggested that a supernova undergoing mixing fallback might be a viable source for the three radionuclides.

  10. On the Injection of Short-lived Radionuclides from a Supernova into the Solar Nebula: Constraints from the Oxygen Isotopes

    NASA Astrophysics Data System (ADS)

    Liu, Ming-Chang

    2014-02-01

    Injection of short-lived radionuclides from a nearby core-collapse Type II supernova into the already-formed solar protoplanetary disk was proposed to account for the former presence of 26Al, 41Ca, and 60Fe in the early solar system inferred from isotopic analysis of meteoritic samples. One potential corollary of this "late-injection" scenario is that the disk's initial (pre-injection) oxygen isotopic composition could be significantly altered, as supernova material that carried the short-lived radionuclides would also deliver oxygen components synthesized in that given star. Therefore, the change in the oxygen isotopic composition of the disk caused by injection could in principle be used to constrain the supernova injection models. Previous studies showed that although supernova oxygen could result in a wide range of shifts in 17O/16O and 18O/16O of the disk, a couple of cases existed where the calculated oxygen changes in the disk would be compatible with the meteoritic and solar wind data. Recently, the initial abundances of 41Ca and 60Fe in the solar system were revised to lower values, and the feasibility of supernova injection as a source for the three radionuclides was called into question. In this study, supernova parameters needed for matching 26Al, 41Ca, and 60Fe to their early solar system abundances were reinvestigated and then were used to infer the pre-injection O-isotope composition of the disk. The result suggested that a supernova undergoing mixing fallback might be a viable source for the three radionuclides.

  11. First Measurement of the Nuclear Carge Radii of Short-Lived Lithium Isotopes

    SciTech Connect

    Nortershauser, W.; Dax, A ..; Ewald, G; Gotte, S; Kirchner, Rolf; Kluge, H J.; Kuhl, T H.; Sanchez, Rodolfo; Wojtaszek, A.; Bushaw, Bruce A.; Drake, Gordon W. F.; Yan, Z C.; Zimmerman, C.

    2006-04-01

    A novel method for the determination of nuclear charge radii of lithium isotopes is presented. Precise laser spectroscopic measurements of the isotope shift in the lithium 2s? 3s transition are combined with highly accurate atomic physics calculation of the mass dependent isotope shift to extract the charge-distribution-sensitive information. This approach has been used to determine the charge radii of 6,7,8,9Li.

  12. Isotope-shift measurements of stable and short-lived lithium isotopes for nuclear-charge-radii determination

    SciTech Connect

    Noertershaeuser, W.; Sanchez, R.; Ewald, G.; Dax, A.; Goette, S.; Kluge, H.-J.; Kuehl, Th.; Wojtaszek, A.; Behr, J.; Bricault, P.; Dilling, J.; Dombsky, M.; Lassen, J.; Levy, C. D. P.; Pearson, M.; Bushaw, B. A.; Drake, G. W. F.; Pachucki, K.; Puchalski, M.; Yan, Z.-C.

    2011-01-15

    Changes in the mean square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a laser spectroscopic approach to determine the charge radii of lithium isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8-ms-lifetime isotope with production rates on the order of only 10 000 atoms/s. The method was applied to all bound isotopes of lithium including the two-neutron halo isotope {sup 11}Li at the on-line isotope separators at GSI, Darmstadt, Germany, and at TRIUMF, Vancouver, Canada. We describe the laser spectroscopic method in detail, present updated and improved values from theory and experiment, and discuss the results.

  13. Mass measurements of short-lived isotopes in a penning trap

    SciTech Connect

    Kern, F.; Egelhof, P.; Hilberath, T.; Kalinowsky, H.; Kluge, H.h.; Kunz, K.; Schweikhard, L.; Stolzenberg, H.; Moore, R.B.; Audi, G.; and others

    1987-12-10

    A mass spectrometer has been set up at the on-line isotope separator ISOLDE at CERN/Geneva. Mass-separated radioactive ions are stored in a Penning trap. Their mass is determined by a measurement of the cyclotron frequency in the magnetic field of a superconducting magnet. A resolving power of up to 300.000 and a precision of some 10 keV were determined in case of mass measurements of neutron-deficient RB and Cs isotopes. The resonance of the isobars /sup 88/Sr and /sup 88/Rb were clearly resolved and evidence was obtained for an isomer in /sup 122/Cs.

  14. Comparison of short-lived medical isotopes activation by laser thin target induced protons and conventional cyclotron proton beams

    NASA Astrophysics Data System (ADS)

    Murray, Joseph; Dudnikova, Galina; Liu, Tung-Chang; Papadopoulos, Dennis; Sagdeev, Roald; Su, J. J.; UMD MicroPET Team

    2014-10-01

    Production diagnostic or therapeutic nuclear medicines are either by nuclear reactors or by ion accelerators. In general, diagnostic nuclear radioisotopes have a very short half-life varying from tens of minutes for PET tracers and few hours for SPECT tracers. Thus supplies of PET and SPECT radiotracers are limited by regional production facilities. For example 18F-fluorodeoxyglucose (FDG) is the most desired tracer for positron emission tomography because its 110 minutes half-life is sufficient long for transport from production facilities to nearby users. From nuclear activation to completing image taking must be done within 4 hours. Decentralized production of diagnostic radioisotopes will be idea to make high specific activity radiotracers available to researches and clinicians. 11 C, 13 N, 15 O and 18 F can be produced in the energy range from 10-20 MeV by protons. Protons of energies up to tens of MeV generated by intense laser interacting with hydrogen containing targets have been demonstrated by many groups in the past decade. We use 2D PIC code for proton acceleration, Geant4 Monte Carlo code for nuclei activation to compare the yields and specific activities of short-lived isotopes produced by cyclotron proton beams and laser driven protons.

  15. Using natural distributions of short-lived radium isotopes to quantify groundwater discharge and recharge

    USGS Publications Warehouse

    Krest, J.M.; Harvey, J.W.

    2003-01-01

    Radium activity in pore water of wetland sediments often differs from the amount expected from local production, decay, and exchange with solid phases. This disequilibrium results from vertical transport of radium with groundwater that flows between the underlying aquifer and surface water. In situations where groundwater recharge or discharge is significant, the rate of vertical water flow through wetland sediment can be determined from the radium disequilibrium by a combined model of transport, production, decay, and exchange with solid phases. We have developed and tested this technique at three sites in the freshwater portion of the Everglades by quantifying vertical advective velocities in areas with persistent groundwater recharge or discharge and estimating a coefficient of dispersion at a site that is subject to reversals between recharge and discharge. Groundwater velocities (v) were determined to be between 0 and -0.5 cm d-1 for a recharge site and 1.5 ?? 0.4 cm d-1 for a discharge site near Levee 39 in the Everglades. Strong gradients in 223Ra and 224Ra usually occurred at the base of the peat layer, which avoided the problems of other tracers (e.g., chloride) for which greatest sensitivity occurs near the peat surface - a zone readily disturbed by processes unrelated to groundwater flow. This technique should be easily applicable to any wetland system with different production rates of these isotopes in distinct sedimentary layers or surface water. The approach is most straightforward in systems where constant pore-water ionic strength can be assumed, simplifying the modeling of radium exchange.

  16. Automated system for neutron activation analysis determination of short lived isotopes at The DOW Chemical Company's TRIGA research reactor

    NASA Astrophysics Data System (ADS)

    Zieman, J. J.; Rigot, W. L.; Romick, J. D.; Quinn, T. J.; Kocher, C. W.

    1994-12-01

    An automated neutron activation analysis (NAA) system for the determination of short lived isotopes was constructed at The DOW Chemical Company's TRIGA Research Reactor in 1993. The NAA group of the Analytical Sciences Laboratory uses the reactor for thousands of analyses each year and therefore automation is important to achieve and maintain high throughput and precision (productivity). This project is complementary to automation of the long-lived counting facilities (see Romick et al., these Proceedings). Canberra/Nuclear Data Systems DEC-based software and electronics modules and an I/O mounting board are the basic commercial components. A Fortran program on a VAX computer controls I/O via ethernet to an Acquisition Interface Module (AIM). The AIM controls the γ spectrometer modules and is interfaced to a Remote Parallel Interface (RPI) module which controls the pneumatic transfer apparatus with TTL signals to the I/O mounting board. Near-infrared sensors are used to monitor key points in the transfer system. Spectra are acquired by a single HPGe detector mounted on a sliding rail to allow flexible and more reproducible counting geometries than with manual sample handling. The maximum sample size is 8 ml in a heat-sealed two dram vial. The sample vial is nested into a "rabbit" vial for irradiation which can be automatically removed prior to spectrum collection. The system was designed to be used by the reactor operator at the control console without the aid of an additional experimenter. Applications include the determination of selenium and silver in coal and water, fluorine in tetra-fluoro ethylene (TFE) coated membranes, aluminum and titanium in composite materials and trace fluorine in non-chlorinated cleaning solvents. Variable dead time software allows analysis for 77mSe despite high dead times from 16N encountered in samples.

  17. Short-lived Radium Isotopes in the Hawaiian Margin: Evidence for Large Fluid Fluxes Through the Puna Ridge

    NASA Astrophysics Data System (ADS)

    Moore, W. S.; Paull, C. K.; Ussler, W.

    2001-12-01

    Techniques to sample and measure short-lived radium isotopes have significantly advanced understanding of groundwater-seawater exchange in coastal areas. The established sampling protocol utilizes traditional wire-line samplers from surface vessels to recover large (200 L) seawater samples. These samples are subsequently passed through Mn-fiber columns at a slow rate (100 L per hour) to assure high radium stripping efficiency. But, sampling near-bottom waters in areas of complicated bathymetry represents a technical challenge for traditional wire-line water sampling equipment. For MBARI's 2001 Hawaii expedition, we built a simple sampler to extract Ra from seawater surrounding the ROV Tiburon. The system uses a variable-flow electric pump to provide 1-2 L/min flow through one of 12 Mn-fiber-filled Ra-stripping canisters mounted on the ROV Tiburon. Values allow the flow to be directed to specific canisters. A flow meter allows the operator to control the flow and compute the volume sampled. The fibers are counted shipboard shortly after vehicle recovery. The ROV proved to be an ideal platform for Ra-sampling because it is able to slowly pump considerable volumes of seawater through the Ra-stripping columns while maintaining close contact with the bottom. Because the manifold was mounted on the ROV's side arm, its interference with other research objectives was minimal. Most of our sampling in Hawaii was conducted as a piggyback effort. We were able to collect 167 radium samples on 37 ROV dives with an average of 206 liters of seawater passing through the stripping canisters. Moreover, we are confident that the sampled waters come from 1-3 above the bottom. We measured significant activities of short-lived radium isotopes, 223Ra (half-life = 11 days) and 224Ra (half-life = 3.7 days), around the margins of the Hawaiian Islands to depths of 3100 m. These measurements suggest numerous groundwater or pore fluid inputs to the surrounding ocean. In general 223Ra activities

  18. Cumulative fission yields of short-lived isotopes under natural-abundance-boron-carbide-moderated neutron spectrum

    SciTech Connect

    Finn, Erin C.; Metz, Lori A.; Greenwood, Lawrence R.; Pierson, Bruce; Wittman, Richard S.; Friese, Judah I.; Kephart, Rosara F.

    2015-04-09

    The availability of gamma spectroscopy data on samples containing mixed fission products at short times after irradiation is limited. Due to this limitation, data interpretation methods for gamma spectra of mixed fission product samples, where the individual fission products have not been chemically isolated from interferences, are not well-developed. The limitation is particularly pronounced for fast pooled neutron spectra because of the lack of available fast reactors in the United States. Samples containing the actinide isotopes 233, 235, 238U, 237Np, and 239Pu individually were subjected to a 2$ pulse in the Washington State University 1 MW TRIGA reactor. To achieve a fission-energy neutron spectrum, the spectrum was tailored using a natural abundance boron carbide capsule to absorb neutrons in the thermal and epithermal region of the spectrum. Our tailored neutron spectrum is unique to the WSU reactor facility, consisting of a soft fission spectrum that contains some measurable flux in the resonance region. This results in a neutron spectrum at greater than 0.1 keV with an average energy of 70 keV, similar to fast reactor spectra and approaching that of 235U fission. Unique fission product gamma spectra were collected from 4 minutes to 1 week after fission using single-crystal high purity germanium detectors. Cumulative fission product yields measured in the current work generally agree with published fast pooled fission product yield values from ENDF/B-VII, though a bias was noted for 239Pu. The present work contributes to the compilation of energy-resolved fission product yield nuclear data for nuclear forensic purposes.

  19. Evidencing lead deposition at the urban scale using "short-lived" isotopic signatures of the source term (Pb-Zn refinery)

    NASA Astrophysics Data System (ADS)

    Franssens, Matthias; Flament, Pascal; Deboudt, Karine; Weis, Dominique; Perdrix, Espéranza

    2004-09-01

    To demonstrate the ability of the lead isotope signature technique to evidence the spatial extent of an industrial Pb deposition plume at a local scale, dry deposition of lead in the urban environment of a Pb-Zn refinery was investigated, as a study case, using transient ("short-lived") isotopic signatures of the industrial source. Sampling campaigns were achieved in representative weather conditions, on an 8-h basis. Dry deposition rates measured downwind from refinery emissions (≈102-103 μg Pb m-2 h-1), cross-sectionally in a 3-5 km radius area around the plant, represent 10-100 times the urban background dry fallout, measured upwind, as well as fallout measured near other potential sources of anthropogenic Pb. The Pb-Zn refinery isotopic signature (approx. 1.100<206Pb/207Pb<1.135) is made identifiable, using the same set of Pb and Zn ores for 2 days before sampling and during field experiments, by agreement with the executive staff of the plant. This source signature is less radiogenic than signatures of urban background Pb aerosols (1.155<206Pb/207Pb<1.165) and minor sources of Pb aerosols (1.147<206Pb/207Pb<1.165). By a simple binary mixing model calculation, we established the extension of the industrial Pb deposition plume. Fifty to eighty percents of total lead settled by the dry deposition mode, 3-4 km away from the refinery, still have an industrial origin. That represents from 40 to 80 μg Pb m-2 h-1, in an area where the blood lead level exceeds 100 μg Pb l-1 for 30% of men and 12% of women living there. We demonstrate here that stable Pb isotope analysis is able to evidence the Pb dry deposition plume in stabilised aerodynamic conditions, using a short-lived source term, suggesting that this methodology is able to furnish valuable data to validate industrial Pb aerosols dispersion models, at the urban scale.

  20. Determination of water ages and flushing rates using short-lived radium isotopes in large estuarine system, the Yangtze River Estuary, China

    NASA Astrophysics Data System (ADS)

    Xu, Bo-Chao; Dimova, Natasha T.; Zhao, Liang; Jiang, Xue-Yan; Yu, Zhi-Gang

    2013-04-01

    We investigated the spatial and temporal distribution of naturally-occurring short-lived radium isotopes (224Ra, t1/2 = 3.6 d and 223Ra, t1/2 = 11 d) to examine coastal water mixing dynamics of the third world largest estuary, Yangtze River Estuary (YRE) during two field trips in April 2010 and May 2011. Distributions of the 224Ra/223Ra activity ratios within the YRE area were used to calculate apparent estuarine water ages. Field-derived results were then compared to hydrodynamic assessments obtained by a Lagrangian particle tracking simulation experiment performed using the Princeton Ocean Model (POM). Water ages obtained via both geotracers and particle tracking agree very well. During both field trips an anomalously "younger" water mass (low salinity and higher radium activities) was observed at about 90-170 km offshore distance from the mouth of the river, suggesting an additional terrestrial water source influenced this area. The temporal distribution of the radium isotopes indicated a semi-diurnal tidal pattern in the YRE with relatively constant isotopic composition of less than a 20% variation during our observations. An integrated water flushing rate based on our observations (excluding the additional anomalous source area) was 8.4 km day-1.

  1. Precision Test of Many-Body QED in the Be+ 2p Fine Structure Doublet Using Short-Lived Isotopes.

    PubMed

    Nörtershäuser, Wilfried; Geppert, Christopher; Krieger, Andreas; Pachucki, Krzysztof; Puchalski, Mariusz; Blaum, Klaus; Bissell, Mark L; Frömmgen, Nadja; Hammen, Michael; Kowalska, Magdalena; Krämer, Jörg; Kreim, Kim; Neugart, Rainer; Neyens, Gerda; Sánchez, Rodolfo; Yordanov, Deyan T

    2015-07-17

    Absolute transition frequencies of the 2s 2S{1/2}→2p2P{1/2,3/2} transitions in Be^{+} were measured for the isotopes ^{7,9-12}Be. The fine structure splitting of the 2p state and its isotope dependence are extracted and compared to results of ab initio calculations using explicitly correlated basis functions, including relativistic and quantum electrodynamics effects at the order of mα(6) and mα(7) ⁢ln α. Accuracy has been improved in both the theory and experiment by 2 orders of magnitude, and good agreement is observed. This represents one of the most accurate tests of quantum electrodynamics for many-electron systems, being insensitive to nuclear uncertainties. PMID:26230786

  2. Assessing and modeling sediment mobility in estuarine and coastal settings due to extreme climate events from natural short-lived isotope distribution

    NASA Astrophysics Data System (ADS)

    Ghaleb, Bassam; Hillaire-Marcel, Claude; Ruiz Fernandez, Ana-Carolina; Sanchez Cabeza, Joan-Albert

    2016-04-01

    Climatic events (e.g. floods, storminess) and management activities (e.g. dredging) may result in the burial or removal and re-suspension of sediments in estuaries and coastal areas. When such sediments are contaminated, such processes may either help restoring better chemical environments or lead to their long-term contamination. Geochemical signatures in surface sediments may help identifying such sedimentological events. However, short-lived isotope data are generally required to set time-constraints on their occurrence. Whereas 210Pb and radioactive fallout isotope contents can help setting time constraints at ~50 to ~100 yr-time scales, natural disequilibria in the 232Th-228Ra-228Th sequence do provide information on processes which occurred within the last 30 yrs, as illustrated in the present study. Box-cored sediments from the Saguenay Fjord and lower estuary of the St. Lawrence (Canada) as well as from estuaries and lagoons from the Sinaloa Coast (Mexico) are used to document the behavior of these isotopes either under relatively steady conditions (St. Lawrence estuary) or under high-frequency extreme climate events (storms and floods; Saguenay Fjord, Coastal Sinaloa). 228Th/232Th activity ratios were determined by chemical extraction of Th and alpha counting of unspiked samples, rapidly after sampling (228Th/232Th). The activity of the intermediate isotope 228Ra was then estimated based on replicate measurements on aliquot samples made a few years later. Under steady conditions, core-top sediment shows an excess in 228Th vs 232Th (AR ~ 1.6), whereas the intermediate 228Ra depicts a deficit vs its parent 232Th (AR ~0.6). Downcore, radioactive decay carries rapidly 228Th-activities to those of the parent 228Ra within about 10 yrs (i.e., ~ 5 half-lives of 228Th), then both move during the next ~20 yrs (~ i.e., ~ 5 half-lives of 228Ra, when added to the 10 yrs of 228Th-excess) towards secular equilibrium with the parent long-lived 232Th. A few algorithms

  3. Extraction of short-lived zirconium and hafnium isotopes usingcrown ethers: A model system for the study of rutherfordium

    SciTech Connect

    Sudowe, Ralf; Calvert, Michael G.; Dullmann, Christoph E.; Farina, Lindsy M.; Folden III, Charles M.; Gregorich, Kenneth E.; Gallaher, Sarah E.H.; Nelson, Sarah L.; Phillips, Diana C.; Schwantes,Jon M.; Wilson, Richard E.; Zielinski Peter M.; Hoffman, Darleane C.; Nitsche Heino

    2005-07-06

    The extraction of zirconium and hafnium from hydrochloric acid media was studied using the crown ethers dibenzo-18-crown-6 (DB18C6), dicyclohexano-18-crown-6 (DC18C6) and dicyclohexano-24-crown-8 (DC24C8) as extractants. The goal was to find an extraction system that exhibits a high selectivity between the members of group 4 of the periodic table and is suitable for the study of rutherfordium. It was found that Zr and Hf are both extracted using DB18C6, DC18C6 and DC24C8. The extraction yield increases with increasing acid concentration and increasing concentration of crown ether. The extracted species most likely consists of an ion-association complex formed between a Zr or Hf chloro complex and a hydronium crown ether complex. Conditions can be found for each extractant that provide for the separation of Zr from Hf. This selective separation between Zr and Hf makes the extraction with crown ethers from HCl well suited to study the extraction behavior of Rf and compare it to the behavior of Zr and Hf. These extraction systems can be used to determine whether the extraction behavior of Rf is similar to Zr, similar to Hf or follows the trend established by the lighter homologs. The extraction kinetics are fast enough for the study of the 78-s isotope {sup 261}Rf.

  4. Isotope shifts of the 6d{sup 2} D{sub 3/2}-7 p{sup 2} P{sub 1/2} transition in trapped short-lived {sup 209-214}Ra{sup +}

    SciTech Connect

    Giri, G. S.; Versolato, O. O.; Berg, J. E. van den; Boell, O.; Dammalapati, U.; Hoek, D. J. van der; Jungmann, K.; Kruithof, W. L.; Mueller, S.; Nunez Portela, M.; Onderwater, C. J. G.; Santra, B.; Timmermans, R. G. E.; Wansbeek, L. W.; Willmann, L.; Wilschut, H. W.

    2011-08-15

    Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has been performed. The isotope shifts of the 6d{sup 2} D{sub 3/2} -7 p{sup 2} P{sub 1/2} transition in {sup 209-214}Ra{sup +}, which are sensitive to the short-range part of the atomic wave functions, were measured. The results are essential experimental input for improving the precision of atomic structure calculations. This is indispensable for parity violation in Ra{sup +} aiming at the determination of the weak mixing angle.

  5. Oxygen isotopic and geochemical evidence for a short-lived, high-temperature hydrothermal event in the Chegem caldera, Caucasus Mountains, Russia

    NASA Astrophysics Data System (ADS)

    Gazis, Carey; Taylor, Hugh P.; Hon, Ken; Tsvetkov, Andrei

    1996-10-01

    Within the 2.8 Ma Chegem ash-flow caldera (11 × 15 km), a single cooling unit of rhyolitic to dacitic welded tuff more than 2 km thick is exposed in deep valleys incised during recent rapid uplift of the Caucasus Mountains. The intracaldera tuff is mineralogically fresh and unaltered, and is overlain by andesite lavas and cut by a resurgent granodiorite intrusion. Major- and trace-element compositions for a 1405-m stratigraphic section of intracaldera tuff display trends of upwardly increasing Na 2O, CaO, A1 2O 3, total Fe, MgO, TiO 2, Sr and Zr and decreasing SiO 2, K 2O and Rb. This mafic-upward zoning (from 76.1 to 69.9% SiO 2) reflects an inverted view of the upper part of the source magma chamber. Oxygen isotope studies of 35 samples from this 1405-m section define a striking profile with "normal" igneous δ18O values (+7.0 to +8.5) in the lower 600 m of tuff, much lower δ18O values (-4.0 to +4.3) in a 700-m zone above that and a shift to high δ18O values (+4.4 to +10.9) in the upper 100 m of caldera-fill exposure. Data from two other partial stratigraphic sections indicate that these oxygen isotope systematics are probably a caldera-wide phenomenon. Quartz and feldspar phenocrysts everywhere have "normal" igneous δ18O values of about +8.5 and +7.5, respectively, whereas groundmass and glass δ18O values range from -7.7 to +12.3. Consequently, the δ18O values of coexisting feldspar, groundmass and glass form a steep array in a plot of δfeldspar vs. δgroundmss/glass. Such pronounced disequilibrium between coexisting feldspar and groundmass or glass has never before been observed on this scale. It requires a hydrothermal event involving large amounts of low- 18O H 2O at sufficiently high temperatures and short enough time (tens of years or less) that glass exchanges thoroughly but feldspar does not. The most likely process responsible for the 18O depletions at Chegem is a very high temperature (500-600 °C), short-lived, vigorous meteoric

  6. Oxygen isotopic and geochemical evidence for a short-lived, high-temperature hydrothermal event in the Chegem caldera, Caucasus Mountains, Russia

    USGS Publications Warehouse

    Gazis, C.; Taylor, H.P.; Hon, K.; Tsvetkov, A.

    1996-01-01

    Within the 2.8 Ma Chegem ash-flow caldera (11 ?? 15 km), a single cooling unit of rhyolitic to dacitic welded tuff more than 2 km thick is exposed in deep valleys incised during recent rapid uplift of the Caucasus Mountains. The intracaldera tuff is mineralogically fresh and unaltered, and is overlain by andesite lavas and cut by a resurgent granodiorite intrusion. Major- and trace-element compositions for a 1405-m stratigraphic section of intracaldera tuff display trends of upwardly increasing Na2O, CaO, Al2O3, total Fe, MgO, TiO2, Sr and Zr and decreasing SiO2, K2O and Rb. This mafic-upward zoning (from 76.1 to 69.9% SiO2) reflects an inverted view of the upper part of the source magma chamber. Oxygen isotope studies of 35 samples from this 1405-m section define a striking profile with "normal" igneous ??18O values (+7.0 to +8.5) in the lower 600 m of tuff, much lower ??18O values (-4.0 to +4.3) in a 700-m zone above that and a shift to high ??18O values (+4.4 to -10.9) in the upper 100 m of caldera-fill exposure. Data from two other partial stratigraphic sections indicate that these oxygen isotope systematics are probably a caldera-wide phenomenon. Quartz and feldspar phenocrysts everywhere have "normal" igneous ??18O values of about +8.5 and +7.5, respectively, whereas groundmass and glass ??18O values range from -7.7 to +12.3. Consequently, the ??18O values of coexisting feldspar, groundmass and glass form a steep array in a plot of ??feldspar vs. ??groundmass/glass. Such pronounced disequilibrium between coexisting feldspar and groundmass or glass has never before been observed on this scale. It requires a hydrothermal event involving large amounts of low-18O H2O at sufficiently high temperatures and short enough time (tens of years or less) that glass exchanges thoroughly but feldspar does not. The most likely process responsible for the O depletions at Chegem is a very high temperature (500-600??C), short-lived, vigorous meteoric-hydrothermal event that was

  7. Short-lived radioactivity and magma genesis

    NASA Astrophysics Data System (ADS)

    Gill, James; Condomines, Michel

    1992-09-01

    Short-lived decay products of uranium and thorium have half-lives and chemistries sensitive to the processes and time scales of magma genesis, including partial melting in the mantle and magmatic differentiation in the crust. Radioactive disequilibrium between U-238, Th-230, and Ra-226 is widespread in volcanic rocks. These disequilibria and the isotopic composition of thorium depend especially on the extent and rate of melting as well as the presence and composition of vapor during melting. The duration of mantle melting may be several hundred millennia, whereas ascent times are a few decades to thousands of years. Differentiation of most magmas commonly occurs within a few millennia, but felsic ones can be tens of millennia old upon eruption.

  8. Short-Lived Climate Pollution

    NASA Astrophysics Data System (ADS)

    Pierrehumbert, R. T.

    2014-05-01

    Although carbon dioxide emissions are by far the most important mediator of anthropogenic climate disruption, a number of shorter-lived substances with atmospheric lifetimes of under a few decades also contribute significantly to the radiative forcing that drives climate change. In recent years, the argument that early and aggressive mitigation of the emission of these substances or their precursors forms an essential part of any climate protection strategy has gained a considerable following. There is often an implication that such control can in some way make up for the current inaction on carbon dioxide emissions. The prime targets for mitigation, known collectively as short-lived climate pollution (SLCP), are methane, hydrofluo-rocarbons, black carbon, and ozone. A re-examination of the issues shows that the benefits of early SLCP mitigation have been greatly exaggerated, largely because of inadequacies in the methodologies used to compare the climate effects of short-lived substances with those of CO2, which causes nearly irreversible climate change persisting millennia after emissions cease. Eventual mitigation of SLCP can make a useful contribution to climate protection, but there is little to be gained by implementing SLCP mitigation before stringent carbon dioxide controls are in place and have caused annual emissions to approach zero. Any earlier implementation of SLCP mitigation that substitutes to any significant extent for carbon dioxide mitigation will lead to a climate irreversibly warmer than will a strategy with delayed SLCP mitigation. SLCP mitigation does not buy time for implementation of stringent controls on CO2 emissions.

  9. The Birth of the Solar System in a Molecular Cloud: Evidence from the Isotopic Pattern of Short-lived Nuclides in the Early Solar System

    NASA Astrophysics Data System (ADS)

    Jacobsen, S. B.

    2005-12-01

    A good positive correlation between the initial solar abundances of short-lived (now extinct) nuclides (when normalized to their nucleosynthetic production ratios) and their mean lifetimes on a logarithmic plot has been well known for some time. Here I show that: (i) the slope for short-lived nuclides in the average interstellar medium in such a diagram is always 1. (ii) for molecular clouds, the slope is expected to be 2 or slightly less than 2 for a model where the molecular clouds are at a steady state and slowly exchange matter with the remaining interstellar medium. The existing data suggest a residence time of ˜ 6 x107 yrs for the matter present in molecular clouds. (iii) the intercept depends on (1) the residence time of matter in molecular clouds, (2) the mass fraction of the interstellar medium that is in molecular clouds, (3) the age of the galaxy and (4) the ratio of the time-average nucleosynthtic production rate and the production rate at the time of solar system formation. (iv) the abundances of 53Mn, 182Hf, 244Pu and 146Sm in the early solar system are likely formed by the same type of supernova sources (SNII?) over the history of our galaxy, while 129I (and possibly 107Pd) were produced in a different type of supernova sources (SNIa?) with the production rate skewed toward the early history of our galaxy. The abundances of these nuclides most likely characterize the average ISM values modified during their residence in the molecular cloud complex where the solar system formed. The abundances of 26Al, 41 Ca and 60Fe are too high to be of galactic production; these must be a contamination from young stellar sources that formed within the proto-Solar molecular cloud. These young sources could not have contributed significant quantities of 53Mn, 182Hf, 244Pu and 146Sm or 129I and thus were dissimilar to typical supernova sources.

  10. Combining radon, short-lived radium isotopes and hydrodynamic modeling to assess submarine groundwater discharge from an anthropized semiarid watershed to a Mediterranean lagoon (Mar Menor, SE Spain)

    NASA Astrophysics Data System (ADS)

    Baudron, Paul; Cockenpot, Sabine; Lopez-Castejon, Francisco; Radakovitch, Olivier; Gilabert, Javier; Mayer, Adriano; Garcia-Arostegui, José Luis; Martinez-Vicente, David; Leduc, Christian; Claude, Christelle

    2015-06-01

    In highly anthropized watersheds, surface water tributaries may carry unexpected high quantities of radon and radium to coastal lagoons. Investigating submarine groundwater discharge (SGD) with radionuclide tracers is therefore a complex task. In order to quantify SGD and decipher the influence of the different water sources, we combined a radon (222Rn) and short-lived radium (223Ra, 224Ra) survey with the hydrodynamic modeling of a lagoon. We applied it to the Mar Menor lagoon (SE Spain) where surface water tributaries and undocumented emissaries carry water from groundwater drainage and brines from groundwater desalinization. We identified the areas of influence of the plume of radionuclides from the river, located major areas of SGD and proposed a location for two submarine emissaries. Porewater, i.e. interstitial water from underlying sediments, was found to be the most representative SGD end member, compared to continental groundwater collected from piezometers. Mass balances in winter and summer seasons provided yearly SGD fluxes of water of 0.4-2.2 ṡ 108 m3/y (222Rn), 4.4-19.0 ṡ 108 m3/y (224Ra) and 1.3 ṡ 108 m3/y (223Ra, measured in winter only). Tidal pumping was identified as a main driver for recirculated saline groundwater, while fresh submarine groundwater discharge from the aquifer ranged between 2% and 23% of total SGD.

  11. Short-lived Supershear Rupture

    NASA Astrophysics Data System (ADS)

    Fukuyama, E.; Xu, S.; Yamashita, F.; Mizoguchi, K.; Takizawa, S.; Kawakata, H.

    2015-12-01

    Fukuyama and Olsen (2002) computed the supershear rupture initiation, propagation and termination process due to a passage of high stress drop area (called asperity) using a boundary integral equation method. They found that supershear rupture continued to propagate after the passage through high stress drop area but it died after a certain propagation distance, which depends on the elastic energy released at the high stress drop area. Here, we could reproduce a similar phenomenon in the laboratory. We conducted large-scale biaxial friction experiments using a pair of meter-scaled metagabbro rock specimens (VP=6.9km/s, VS=3.6km/s) at the National Research institute for Earth Science and Disaster Prevention (NIED). We observed several stick slip rupture events that initiated close to an asperity and immediately became supershear ruptures. But after propagating certain distance they died out and co-existing subshear ruptures became prominent. If we look into details, during the supershear rupture, we could see a sequence of rupture acceleration, its short rest and re-acceleration. This feature reminds us of a sequential breakage of small high stress patches as predicted by Fukuyama and Madariaga (2000). These observations might be interpreted under a concept of energy balance where the energy transmission from strain energy released by the asperity to fracture energy consumed at the crack tip was not instantaneously balanced in space. This could be related to the fact that earthquake rupture velocity is rather smooth reported from the finite fault analysis of large earthquakes with seismic waveforms. References Fukuyama, E. and R. Madariaga (2000) Dynamic propagation and interaction of a rupture front on a planar fault, PAGEOPH, 257, 1959-1979. Fukuyama, E. and K.B. Olsen (2002) A condition for super-shear rupture propagation in a heterogeneous stress field, PAGEOPH, 159, 2047-2056.

  12. Skylab short-lived event alert program

    NASA Technical Reports Server (NTRS)

    Citron, R. A.

    1974-01-01

    During the three manned Skylab missions, the Center for Short-Lived Phenomena (CSLP) reported a total of 39 significant events to the Johnson Space Center (JSC) as part of the Skylab Short-Lived Event Alert Program. The telegraphed daily status reports included the names and locations of the events, the track number and revolution number during which the event could be observed, the time (GMT) to within plus or minus 2 sec when Skylab was closest to the event area, and the light condition (daylight or darkness) at that time and place. The messages sent to JSC during the Skylab 4 mission also included information pertaining to ground-truth studies and observations being conducted on the events. Photographic priorities were assigned for each event.

  13. Alchemy with short-lived radionuclides

    SciTech Connect

    Rubio, F.F.; Finn, R.D.; Gilson, A.J.

    1981-04-01

    A variety of short-lived radionuclides are produced and subsequently incorporated into radiopharmaceutical compounds in the radionuclide production program currently being conducted at the Cyclotron Facility of Mount Sinai Medical Center. The recovery of high specific activity oxygen-15 labelled water prepared by means of an inexpensive system operating in conjunction with an on-line radiogas target routinely utilized for oxygen-15 labelled carbon dioxide studies is currently receiving particular attention.

  14. Short-lived Extinct Radioactivities and the Birth of the Sun

    NASA Astrophysics Data System (ADS)

    Meyer, Bradley

    2002-10-01

    Extinct radioactivities are isotopes that were extant at the time of formation of the solar system but that have since decayed. Their abundances may be inferred from isotopic anomalies in the daughter isotopes, and these data provide valuable constraints on the circumstance of the birth of our Sun. Remarkably, among ten or so isotopes we are convinced were alive in the early solar nebula, only two or three agree with expectations from Galactic nucleosynthesis. The r-process isotopes tend to be lower in the meteorites than a naive Galactic nucleosynthesis would imply, and the short-lived species seem to have had extra production from either a nearby star or from energetic particles from the early Sun. This talk will review the data available and then will attempt to reconcile the abundances of the short-lived radioactivities with appropriate models for Galactic chemical evolution and the astrophysical setting of the Sun's birth.

  15. Malaria Vaccine Protection Short-Lived in Young Children

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159656.html Malaria Vaccine Protection Short-Lived in Young Children Kids ... 30, 2016 (HealthDay News) -- The world's most promising malaria vaccine appears to offer short-lived protection, fading ...

  16. Short-Lived Radioactivities and the Birth of the sun

    NASA Astrophysics Data System (ADS)

    Meyer, Bradley S.; Clayton, Donald D.

    2000-04-01

    Now extinct short-lived radioactive isotopes were apparently extant in the early solar system. Their abundances can be inferred from isotopic effects in their daughter nuclei in primitive meteorites, and the deviation of these abundances from expectations from continuous galactic nucleosynthesis yields important information on the last nucleosynthetic events that contributed new nuclei to the solar system and on the general circumstances of the Sun's birth. In this paper we present a rudimentary model that attempts to reconcile the abundances of ten short-lived radioactivities in the early solar system. In broad outlines, the picture requires 1) that Type Ia supernovae maintained a steady ISM supply of 53Mn and 146Sm, 2) that the r-process events that slowly admixed new 107Pd, 129I, 182Hf, and 244Pu nuclei to the solar system occurred over an interval of several hundred million years prior to solar system formation, and 3) that a massive star, by injecting only material outside its helium-exhausted core into the proto-solar nebula, contributed 26Al, 36Cl, 41Ca, 60Fe, and 182Hf no more than one million years prior to the Sun's birth. In this picture, the live 182Hf present in the early solar system was not due to r-process production but rather to a fast s-process in helium or carbon burning shell in the massive star. We conclude with a possible chemical-memory explanation for the putative 53Cr/52Cr gradient in the solar system.

  17. Sinusoidal Regge Oscillations from Short Lived Resonances

    NASA Astrophysics Data System (ADS)

    Sokolovski, D.; Felfli, Z.; Msezane, A. Z.

    2007-06-01

    It is well known that a resonance with a large angular life can produce sharp Breit-Wigner peaks in the energy dependence of integral cross sections [1,2]. Here we show that a short-lived resonance whose angular life is of order of one full rotation may produce a different kind of contribution to the integral cross section. This contribution has a sinousoidal form and its frequency is determined by the rotational constant of the complex. As one of the examples, we analyze the Regge oscillations observed in numerical simulations of the F+H2(v=0,j=0,φ=0) ->FH(v'=2,j'=0,φ'=0) + H reaction. In particular, we show that these oscillations are produced by two overlapping resonances located near the transition state and the van der Waals well, respectively [3]. [1] J. H. Macek, et al., Phys. Rev. Lett., 93, 183202, (2004). [2] Z. Felfli et al., J. Phys. B 39, L353 (2006) [3] D. Sokolovski, D. De Fazio, S. Cavalli and V. Aquilanti, J. Chem. Phys. (2007) (submitted).

  18. Short course on St-02 applications of isotope dilutions and isotopic measurements

    SciTech Connect

    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.

  19. Studies of images of short lived events using ERTS data

    NASA Technical Reports Server (NTRS)

    Deutschman, W. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The program to study short-lived events with the ERTS-1 satellite has evaluated 97 events reported by the Center for Short-Lived Phenomena. Forty-eight of these events were listed as candidates for ERTS-1 coverage and 8 of these were considered significant enough to immediately alert the ERTS operation staff by telephone. Studies of the images received from six events indicate that useful data on short-lived events can be obtained from ERTS-1 that would be difficult or impossible to obtain by other methods.

  20. Caffeine's Jolt Can Sometimes Be Short-Lived

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159413.html Caffeine's Jolt Can Sometimes Be Short-Lived Stimulant effect ... 17, 2016 THURSDAY, June 16, 2016 (HealthDay News) -- Caffeine no longer improves alertness or mental performance after ...

  1. Overview of the methods for the measurement and interpretation of short-lived radioisotopes and their limits

    NASA Astrophysics Data System (ADS)

    Ghaleb, B.

    2009-01-01

    The daughter products of the uranium and thorium series consist of several radioactive isotopes with half-lives varying from less than a second to 105 years. Combining their half-live with their geochemical behaviour some of these radioisotopes could be used as tracers and/or chronometers of sedimentary processes. For example, thorium isotopes, and to a lesser extent polonium isotopes are characterized by very low solubility and very high affinity for the surface of particles. Consequently, thorium isotopes can be used to document scavenging and adsorption processes. On the other hand, radium isotopes tend to remain in solution and can be used to document diffusion processes. In the following, we present the analytical methods for the measurement and analysis of the most common short-lived isotopes and throughout their utility in studying sedimentary processes will be illustrated by a few examples of applications. These examples will focus essentially on the applications of short lived thorium isotopes (notably 234Th) and the use of 210Pb as chronometer for recent sedimentary accumulation.

  2. Experimental Measurements of Short-Lived Fission Products from Uranium, Neptunium, Plutonium and Americium

    SciTech Connect

    Metz, Lori A.; Payne, Rosara F.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Pierson, Bruce D.

    2009-11-01

    Fission yields are especially well characterized for long-lived fission products. Modeling techniques incorporate numerous assumptions and can be used to deduce information about the distribution of short-lived fission products. This work is an attempt to gather experimental (model-independent) data on the short-lived fission products. Fissile isotopes of uranium, neptunium, plutonium and americium were irradiated under pulse conditions at the Washington State University 1 MW TRIGA reactor to achieve ~108 fissions. The samples were placed on a HPGe (high purity germanium) detector to begin counting in less than 3 minutes post irradiation. The samples were counted for various time intervals ranging from 5 minutes to 1 hour. The data was then analyzed to determine which radionuclides could be quantified and compared to the published fission yield data.

  3. Prospects for baryon instability search with long-lived isotopes

    SciTech Connect

    Efremenko, Yu.; Bugg, W.; Cohn, H.; Kamyshkov, Yu.; Parker, G.; Plasil, F.

    1996-12-31

    In this paper we consider the possibility of observation of baryon instability processes occurring inside nuclei by searching for the remnants of such processes that could have been accumulated in nature as mm long-lived isotopes. As an example, we discuss here the possible detection of traces of {sup 97}Tc, {sup 98}Tc, and {sup 99}Tc in deep-mined nonradioactive tin ores.

  4. Short-lived oxygen diffusion during hot, deep-seated meteoric alteration of anorthosite

    PubMed

    Mora; Riciputi; Cole

    1999-12-17

    Heterogeneous oxygen isotope compositions of plagioclase from the Boehls Butte anorthosite include some of the most oxygen-18-depleted values (to -16 per mil) reported for plagioclase in meta-igneous rocks and indicate high-temperature (T > 500 degrees C) isotopic exchange between plagioclase and nearly pristine meteoric fluid. Retrograde reaction-enhanced permeability assisted influx of meteoric-hydrothermal fluids into the deep-seated anorthosite. Isotopic gradients of about 14 per mil over 600 micrometers in single crystals require short-lived (about 10(4) years) diffusional exchange of oxygen and locally large effective water:rock ratios, followed by rapid loss of water and cessation of oxygen diffusion in the anorthosite. PMID:10600738

  5. Short-lived oxygen diffusion during hot, deep-seated meteoric alteration of anorthosite

    PubMed

    Mora; Riciputi; Cole

    1999-12-17

    Heterogeneous oxygen isotope compositions of plagioclase from the Boehls Butte anorthosite include some of the most oxygen-18-depleted values (to -16 per mil) reported for plagioclase in meta-igneous rocks and indicate high-temperature (T > 500 degrees C) isotopic exchange between plagioclase and nearly pristine meteoric fluid. Retrograde reaction-enhanced permeability assisted influx of meteoric-hydrothermal fluids into the deep-seated anorthosite. Isotopic gradients of about 14 per mil over 600 micrometers in single crystals require short-lived (about 10(4) years) diffusional exchange of oxygen and locally large effective water:rock ratios, followed by rapid loss of water and cessation of oxygen diffusion in the anorthosite.

  6. Soot and short-lived pollutants provide political opportunity

    NASA Astrophysics Data System (ADS)

    Victor, David G.; Zaelke, Durwood; Ramanathan, Veerabhadran

    2015-09-01

    Cutting levels of soot and other short-lived pollutants delivers tangible benefits and helps governments to build confidence that collective action on climate change is feasible. After the Paris climate meeting this December, actually reducing these pollutants will be essential to the credibility of the diplomatic process.

  7. A generalized method for characterization of 235U and 239Pu content using short-lived fission product gamma spectroscopy

    NASA Astrophysics Data System (ADS)

    Knowles, Justin; Skutnik, Steven; Glasgow, David; Kapsimalis, Roger

    2016-10-01

    Rapid nondestructive assay methods for trace fissile material analysis are needed in both nuclear forensics and safeguards communities. To address these needs, research at the Oak Ridge National Laboratory High Flux Isotope Reactor Neutron Activation Analysis facility has developed a generalized nondestructive assay method to characterize materials containing fissile isotopes. This method relies on gamma-ray emissions from short-lived fission products and makes use of differences in fission product yields to identify fissile compositions of trace material samples. Although prior work has explored the use of short-lived fission product gamma-ray measurements, the proposed method is the first to provide a complete characterization of isotopic identification, mass ratios, and absolute mass determination. Successful single fissile isotope mass recoveries of less than 6% recovery bias have been conducted on standards of 235U and 239Pu as low as 12 ng in less than 10 minutes. Additionally, mixtures of fissile isotope standards containing 235U and 239Pu have been characterized as low as 198 ng of fissile mass with less than 7% recovery bias. The generalizability of this method is illustrated by evaluating different fissile isotopes, mixtures of fissile isotopes, and two different irradiation positions in the reactor. It is anticipated that this method will be expanded to characterize additional fissile nuclides, utilize various irradiation facilities, and account for increasingly complex sample matrices.

  8. A generalized method for characterization of 235U and 239Pu content using short-lived fission product gamma spectroscopy

    DOE PAGESBeta

    Knowles, Justin R.; Skutnik, Steven E.; Glasgow, David C.; Kapsimalis, Roger J.

    2016-06-23

    Rapid non-destructive assay methods for trace fissile material analysis are needed in both nuclear forensics and safeguards communities. To address these needs, research at the High Flux Isotope Reactor Neutron Activation Analysis laboratory has developed a generalized non-destructive assay method to characterize materials containing fissile isotopes. This method relies on gamma-ray emissions from short-lived fission products and capitalizes off of differences in fission product yields to identify fissile compositions of trace material samples. Although prior work has explored the use of short-lived fission product gamma-ray measurements, the proposed method is the first to provide a holistic characterization of isotopic identification,more » mass ratios, and absolute mass determination. Successful single fissile isotope mass recoveries of less than 6% error have been conducted on standards of 235U and 239Pu as low as 12 nanograms in less than 10 minutes. Additionally, mixtures of fissile isotope standards containing 235U and 239Pu have been characterized as low as 229 nanograms of fissile mass with less than 12% error. The generalizability of this method is illustrated by evaluating different fissile isotopes, mixtures of fissile isotopes, and two different irradiation positions in the reactor. Furthermore, it is anticipated that this method will be expanded to characterize additional fissile nuclides, utilize various irradiation sources, and account for increasingly complex sample matrices.« less

  9. Measures Urged to Cut Short-Lived Climate Pollutants

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2013-03-01

    To produce significant near-term climate benefits, the Obama administration should take a series of actions under existing authorities to reduce greenhouse gases that have relatively short atmospheric lifetimes of weeks to a few decades, according to a 12 March study by the nonprofit Center for Climate and Energy Solutions (C2ES). The report, "Domestic Policies to Reduce the Near-Term Risks of Climate Change," notes that recent estimates suggest that about 30-40% of warming experienced to date can be attributed to these short-lived pollutants, which include black carbon, methane, and hydrofluorocarbons (HFCs).

  10. Short-lived positron emitter labeled radiotracers - present status

    SciTech Connect

    Fowler, J.S.; Wolf, A.P.

    1982-01-01

    The preparation of labelled compounds is important for the application of positron emission transaxial tomography (PETT) in biomedical sciences. This paper describes problems and progress in the synthesis of short-lived positron emitter (/sup 11/C, /sup 18/F, /sup 13/N) labelled tracers for PETT. Synthesis of labelled sugars, amino acids, and neurotransmitter receptors (pimozide and spiroperidol tagged with /sup 11/C) is discussed in particular. (DLC)

  11. SPATIAL Short Courses Build Expertise and Community in Isotope Geochemistry

    NASA Astrophysics Data System (ADS)

    Riggs, E. M.; Bowen, G. J.

    2015-12-01

    The SPATIAL short course at the University of Utah is designed for graduate students and professionals in the earth and environmental sciences from around the globe. An integral part of the broader, NSF-funded Inter-university Training for Continental-scale Ecology (ITCE) project, the course is an intensive two-week field, classroom and laboratory experience with internationally-known researchers as instructors. The course focuses on stable isotope geochemistry coupled with spatial analysis techniques. Participants do not typically know each other or this research community well upon entering. One of the stated goals of the overall project is to build a community of practice around these techniques. This design is common in many professional fields, but is not often applied at the graduate level nor formally assessed in the earth sciences. Paired pre- and post-tests were administered before the start and after the close of the short courses over 3 years. The survey is a set of instruments adapted from social-cognitive psychology measuring changes in identity and community with other items to measure content knowledge outcomes. We see a subtle, consistent convergence of identities between large-scale isotope geochemistry and participants' research areas. Results also show that the course generates an increase in understanding about stable isotopes' use and application. The data show the SPATIAL course is very effective at bringing students together socially with each other and with faculty to create an environment that fosters community and scientific cooperation. Semi-structured pre-and post- interviews were conducted to understand the program elements that generated gains in learning and community. Participants were selected based on initial responses on the pre-survey to capture the range of initial conditions for the group. Qualitative analysis shows that the major factors for participants were 1) ready access to researchers in an informal setting during the

  12. ``Sleeping reactor`` irradiations: Shutdown reactor determination of short-lived activation products

    SciTech Connect

    Jerde, E.A.; Glasgow, D.C.

    1998-09-01

    At the High-Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory, the principal irradiation system has a thermal neutron flux ({phi}) of {approximately} 4 {times} 10{sup 14} n/cm{sup 2} {center_dot} s, permitting the detection of elements via irradiation of 60 s or less. Irradiations of 6 or 7 s are acceptable for detection of elements with half-lives of as little as 30 min. However, important elements such as Al, Mg, Ti, and V have half-lives of only a few minutes. At HFIR, these can be determined with irradiation times of {approximately} 6 s, but the requirement of immediate counting leads to increased exposure to the high activity produced by irradiation in the high flux. In addition, pneumatic system timing uncertainties (about {+-} 0.5 s) make irradiations of < 6 s less reliable. Therefore, the determination of these ultra-short-lived species in mixed matrices has not generally been made at HFIR. The authors have found that very short lived activation products can be produced easily during the period after reactor shutdown (SCRAM), but prior to the removal of spent fuel elements. During this 24- to 36-h period (dubbed the ``sleeping reactor``), neutrons are produced in the beryllium reflector by the reaction {sup 9}Be({gamma},n){sup 8}Be, the gamma rays principally originating in the spent fuel. Upon reactor SCRAM, the flux drops to {approximately} 1 {times} 10{sup 10} n/cm{sup 2} {center_dot} s within 1 h. By the time the fuel elements are removed, the flux has dropped to {approximately} 6 {times} 10{sup 8}. Such fluxes are ideal for the determination of short-lived elements such as Al, Ti, Mg, and V. An important feature of the sleeping reactor is a flux that is not constant.

  13. SHORT-LIVED RADIO BURSTS FROM THE CRAB PULSAR

    SciTech Connect

    Crossley, J. H.; Eilek, J. A.; Hankins, T. H.; Kern, J. S.

    2010-10-20

    Our high-time-resolution observations reveal that individual main pulses from the Crab pulsar contain one or more short-lived microbursts. Both the energy and duration of bursts measured above 1 GHz can vary dramatically in less than a millisecond. These fluctuations are too rapid to be caused by propagation through turbulence in the Crab Nebula or in the interstellar medium; they must be intrinsic to the radio emission process in the pulsar. The mean duration of a burst varies with frequency as {nu}{sup -2}, significantly different from the broadening caused by interstellar scattering. We compare the properties of the bursts to some simple models of microstructure in the radio emission region.

  14. Nucleosynthesis of Short-lived Radioactivities in Massive Stars

    NASA Technical Reports Server (NTRS)

    Meyer, B. S.

    2004-01-01

    A leading model for the source of many of the short-lived radioactivities in the early solar nebula is direct incorporation from a massive star [1]. A recent and promising incarnation of this model includes an injection mass cut, which is a boundary between the stellar ejecta that become incorporated into the solar cloud and those ejecta that do not [2-4]. This model also includes a delay time between ejection from the star and incorporation into early solar system solid bodies. While largely successful, this model requires further validation and comparison against data. Such evaluation becomes easier if we have a better sense of the nature of the synthesis of the various radioactivities in the star. That is the goal of this brief abstract.

  15. Disposal of BRC wastes containing short-lived radionuclides

    SciTech Connect

    Rogers, V.C.; Baird, R.D.

    1986-01-01

    As part of its responsibility for the safe disposal of low-level (radioactive) waste (LLW), the Texas Low-Level Radioactive Waste Disposal Authority sponsored an analysis of the use of permitted sanitary landfills for the disposal of wastes containing only low concentrations of radionuclides with half-lives of <300 days. Analyses have been performed giving limits on concentrations and total curies annually disposed for 56 short-lived radionuclides. The Low-Level Radioactive Waste Policy Amendments Act, enacted in December 1985, has directed the US Nuclear Regulatory Commission (NRC) to develop standards and procedures for considering and acting on petitions for below regulatory concern (BRC) radioactive waste disposal within 6 months. The NRC has developed a de minimis biomedical waste disposal rule for H-3 and C-14 that places limits on concentrations that can be disposed of without regard to radioactivity. Likewise, the US Environmental Protection Agency (EPA) is developing a regulation for the disposal of BRC radioactive wastes in a sanitary landfill as part of their LLW disposal rulemaking. The purpose of this study is to: 1) conduct multipathway risk assessments using the same methodology that is being used by the EPA for the technical support of their BRC rulemaking; 2) obtain radionuclide concentration and annual total curie limits from the results of the risk assessments by limiting the health impacts to guideline values used in this analysis; and 3) present other restrictions or conditions that emerge from the analysis.

  16. Laser spectroscopy of trapped short-lived Ra{sup +} ions

    SciTech Connect

    Versolato, O. O.; Giri, G. S.; Wansbeek, L. W.; Berg, J. E. van den; Hoek, D. J. van der; Jungmann, K.; Kruithof, W. L.; Onderwater, C. J. G.; Sahoo, B. K.; Santra, B.; Shidling, P. D.; Timmermans, R. G. E.; Willmann, L.; Wilschut, H. W.

    2010-07-15

    As an important step toward an atomic parity violation experiment in one single trapped Ra{sup +} ion, laser spectroscopy on short-lived {sup 212,213,214}Ra{sup +} ions was conducted. The isotope shift of the 6 {sup 2}D{sub 3/2}-7 {sup 2}P{sub 1/2} and 6 {sup 2}D{sub 3/2}-7 {sup 2}P{sub 3/2} transitions and the hyperfine structure constants of the 7 {sup 2}P{sub 1/2} and 6 {sup 2}D{sub 3/2} states in {sup 213}Ra{sup +} were measured, which provides a benchmark for the required atomic theory. A lower limit of 232(4) ms for 6 {sup 2}D{sub 5/2} state lifetime was determined.

  17. A multi-proxy approach to identifying short-lived marine incursions in the Early Carboniferous

    NASA Astrophysics Data System (ADS)

    Bennett, Carys; Davies, Sarah; Leng, Melanie; Snelling, Andrea; Millward, David; Kearsey, Timothy; Marshall, John; Reves, Emma

    2015-04-01

    This study is a contribution to the TW:eed Project (Tetrapod World: early evolution and diversification), which examines the rebuilding of Carboniferous ecosystems following a mass extinction at the end of the Devonian. The project focuses on the Tournaisian Ballagan Formation of Scotland and the Borders, which contains rare fish and tetrapod material. The Ballagan Formation is characterised by sandstones, dolomitic cementstones, paleosols, siltstones and gypsum deposits. The depositional environment ranges from fluvial, alluvial-plain to marginal-marine environments, with fluvial, floodplain and lacustrine deposition dominant. A multi-proxy approach combining sedimentology, palaeontology, micropalaeontology, palynology and geochemistry is used to identify short-lived marine transgressions onto the floodplain environment. Rare marginal marine fossils are: Chondrites-Phycosiphon, Spirorbis, Serpula, certain ostracod species, rare orthocones, brachiopods and putative marine sharks. More common non-marine fauna include Leiocopida and Podocopida ostracods, Mytilida and Myalinida bivalves, plants, eurypterids, gastropods and fish. Thin carbonate-bearing dolomitic cementstones and siltstone contain are the sedimentary deposits of marine incursions and occur throughout the formation. Over 600 bulk carbon isotope samples were taken from the 500 metre thick Norham Core (located near Berwick-Upon-Tweed), encompassing a time interval of around 13 million years. The results range from -26o to -19 δ13Corg, with an average of -19o much lighter than the average value for Early Carboniferous marine bulk organic matter (δ13C of -28 to -30). The isotope results correspond to broad-scale changes in the depositional setting, with more positive δ13C in pedogenic sediments and more negative δ13C in un-altered grey siltstones. They may also relate to cryptic (short-lived) marine incursions. A comparison of δ13C values from specific plant/wood fragments, palynology and bulk

  18. Studies of images of short-lived events using ERTS data

    NASA Technical Reports Server (NTRS)

    Deutschman, W. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Significant results are the continued detection of short-lived events. The following have been detected and analyzed: forest fires, oil spills, vegetation damage, volcanoes, storm ridges, and earthquakes. It is hoped that the Mississippi River flood scenes will arrive shortly and then floods be added to the list of identified short-lived events.

  19. Constraints on the Origin of Chondrules and CAIs from Short-Lived and Long-Lived Radionuclides

    SciTech Connect

    Kita, N T; Huss, G R; Tachibana, S; Amelin, Y; Nyquist, L E; Hutcheon, I D

    2005-10-24

    The high time resolution Pb-Pb ages and short-lived nuclide based relative ages for CAIs and chondrules are reviewed. The solar system started at 4567.2 {+-} 0.6Ma inferred from the high precision Pb-Pb ages of CAIs. Time scales of CAIs ({le}0.1Myr), chondrules (1-3Myr), and early asteroidal differentiation ({ge}3Myr) inferred from {sup 26}Al relative ages are comparable to the time scale estimated from astronomical observations of young star; proto star, classical T Tauri star and week-lined T Tauri star, respectively. Pb-Pb ages of chondrules also indicate chondrule formation occur within 1-3 Myr after CAIs. Mn-Cr isochron ages of chondrules are similar to or within 2 Myr after CAI formation. Chondrules from different classes of chondrites show the same range of {sup 26}Al ages in spite of their different oxygen isotopes, indicating that chondrule formed in the localized environment. The {sup 26}Al ages of chondrules in each chondrite class show a hint of correlation with their chemical compositions, which implies the process of elemental fractionation during chondrule formation events.

  20. Efficiency of short-lived halogens at influencing climate through depletion of stratospheric ozone

    NASA Astrophysics Data System (ADS)

    Hossaini, R.; Chipperfield, M. P.; Montzka, S. A.; Rap, A.; Dhomse, S.; Feng, W.

    2015-03-01

    Halogens released from long-lived anthropogenic substances, such as chlorofluorocarbons, are the principal cause of recent depletion of stratospheric ozone, a greenhouse gas. Recent observations show that very short-lived substances, with lifetimes generally under six months, are also an important source of stratospheric halogens. Short-lived bromine substances are produced naturally by seaweed and phytoplankton, whereas short-lived chlorine substances are primarily anthropogenic. Here we used a chemical transport model to quantify the depletion of ozone in the lower stratosphere from short-lived halogen substances, and a radiative transfer model to quantify the radiative effects of that ozone depletion. According to our simulations, ozone loss from short-lived substances had a radiative effect nearly half that from long-lived halocarbons in 2011 and, since pre-industrial times, has contributed a total of about -0.02 W m-2 to global radiative forcing. We find natural short-lived bromine substances exert a 3.6 times larger ozone radiative effect than long-lived halocarbons, normalized by halogen content, and show atmospheric levels of dichloromethane, a short-lived chlorine substance not controlled by the Montreal Protocol, are rapidly increasing. We conclude that potential further significant increases in the atmospheric abundance of short-lived halogen substances, through changing natural processes or continued anthropogenic emissions, could be important for future climate.

  1. Convective transport of very short lived bromocarbons to the stratosphere

    NASA Astrophysics Data System (ADS)

    Liang, Q.; Atlas, E.; Blake, D.; Dorf, M.; Pfeilsticker, K.; Schauffler, S.

    2014-06-01

    We use the NASA Goddard Earth Observing System (GEOS) Chemistry Climate Model (GEOSCCM) to quantify the contribution of the two most important brominated very short lived substances (VSLSs), bromoform (CHBr3) and dibromomethane (CH2Br2), to stratospheric bromine and its sensitivity to convection strength. Model simulations suggest that the most active transport of VSLSs from the marine boundary layer through the tropopause occurs over the tropical Indian Ocean, the tropical western Pacific, and off the Pacific coast of Mexico. Together, convective lofting of CHBr3 and CH2Br2 and their degradation products supplies ~8 ppt total bromine to the base of the tropical tropopause layer (TTL, ~150 hPa), similar to the amount of VSLS organic bromine available in the marine boundary layer (~7.8-8.4 ppt) in the active convective lofting regions mentioned above. Of the total ~8 ppt VSLS bromine that enters the base of the TTL at ~150 hPa, half is in the form of organic source gases and half in the form of inorganic product gases. Only a small portion (<10%) of the VSLS-originated bromine is removed via wet scavenging in the TTL before reaching the lower stratosphere. On average, globally, CHBr3 and CH2Br2 together contribute ~7.7 pptv to the present-day inorganic bromine in the stratosphere. However, varying model deep-convection strength between maximum (strongest) and minimum (weakest) convection conditions can introduce a ~2.6 pptv uncertainty in the contribution of VSLSs to inorganic bromine in the stratosphere (BryVSLS). Contrary to conventional wisdom, the minimum convection condition leads to a larger BryVSLS as the reduced scavenging in soluble product gases, and thus a significant increase in product gas injection (2-3 ppt), greatly exceeds the relatively minor decrease in source gas injection (a few 10ths ppt).

  2. Effects of salience are both short- and long-lived.

    PubMed

    Orquin, Jacob L; Lagerkvist, Carl Johan

    2015-09-01

    A salient object can attract attention irrespective of its relevance to current goals. However, this bottom up effect tends to be short-lived (e.g. <150 ms) and it is generally assumed that top down processes such as goals or task instructions operating in later time windows override the effect of salience operating in early time windows. While the majority of studies on visual search and scene viewing comply with the assumptions of top down and bottom up processes operating in different time windows and that the former overrides the latter, we point to some possible anomalies in decision research. To explore these anomalies and thereby test the two key assumptions, we manipulate the salience and valence of one information cue in a decision task. Our analyses reveal that in decision tasks top down and bottom up processes do not operate in different time windows as predicted, nor does the former process necessarily override the latter. Instead, we find that the maximum effect of salience on the likelihood of making a saccade to the target cue is delayed until about 20 saccades after stimulus onset and that the effects of salience and valence are additive rather than multiplicative. Further, we find that in the positive and neutral valence conditions, salience continues to exert pressure on saccadic latency, i.e. the interval between saccades to the target with high salience targets being fixated faster than low salience targets. Our findings challenge the assumption that top down and bottom up processes operate in different time windows and the assumption that top down processes necessarily override bottom up processes. PMID:26188691

  3. First Use of High Charge States for Mass Measurements of Short-Lived Nuclides in a Penning Trap

    SciTech Connect

    Ettenauer, S.; Gallant, A. T.; Dilling, J.; Simon, M. C.; Chaudhuri, A.; Mane, E.; Delheij, P.; Pearson, M. R.; Brunner, T.; Chowdhury, U.; Simon, V. V.; Brodeur, M.; Andreoiu, C.; Audi, G.; Lopez-Urrutia, J. R. Crespo; Ullrich, J.; Gwinner, G.; Lapierre, A.; Lunney, D.; Ringle, R.

    2011-12-30

    Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q=8-12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed {beta} emitter {sup 74}Rb (T{sub 1/2}=65 ms). The determination of its atomic mass and an improved Q{sub EC} value are presented.

  4. First use of high charge states for mass measurements of short-lived nuclides in a Penning trap.

    PubMed

    Ettenauer, S; Simon, M C; Gallant, A T; Brunner, T; Chowdhury, U; Simon, V V; Brodeur, M; Chaudhuri, A; Mané, E; Andreoiu, C; Audi, G; López-Urrutia, J R Crespo; Delheij, P; Gwinner, G; Lapierre, A; Lunney, D; Pearson, M R; Ringle, R; Ullrich, J; Dilling, J

    2011-12-30

    Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q=8-12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed β emitter 74Rb (T(1/2)=65  ms). The determination of its atomic mass and an improved Q(EC) value are presented.

  5. Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes

    SciTech Connect

    Marinov, A.; Kashiv, Y.; Rodushkin, I.; Halicz, L.; Segal, I.; Pape, A.; Miller, H. W.; Kolb, D.; Brandt, R.

    2007-08-15

    Four long-lived neutron-deficient Th isotopes with atomic mass numbers 211 to 218 and abundances of (1-10)x10{sup -11} relative to {sup 232}Th have been found in a study of naturally-occurring Th using inductively coupled plasma-sector field mass spectrometry. It is deduced that long-lived isomeric states exist in these isotopes. The hypothesis that they might belong to a new class of long-lived high spin super- and hyperdeformed isomeric states is discussed.

  6. Design Study for a Multi-Reflection Time-of-Flight Mass Spectrograph for Very Short Lived Nuclei

    NASA Astrophysics Data System (ADS)

    Yoon, Jin Woo; Park, Young-Ho; Im, Kang-Bin; Kim, Gi Dong; Kim, Yong Kyun

    The multi-reflection time-of-flight mass spectrometer (MR-TOF-MS) has been designed for the high precision mass measurement system in RAON accelerator facility, which will be constructed in Korea. Mirror-electrode potentials were numerically optimized by Nelder-Mead algorithm. The temporal spread and the mass-resolving power were calculated for the 132Sn+ ions with an energy spread of 20 eV and an emittance of 3 π mm mrad; the mass resolving power over 105 was achieved. MR-TOF-MS will be used for the isobar separation and the mass measurement for very short-lived isotopes.

  7. Short-lived isomers in 192Po and 194Po

    NASA Astrophysics Data System (ADS)

    Andel, B.; Andreyev, A. N.; Antalic, S.; Heßberger, F. P.; Ackermann, D.; Hofmann, S.; Huyse, M.; Kalaninová, Z.; Kindler, B.; Kojouharov, I.; Kuusiniemi, P.; Lommel, B.; Nishio, K.; Page, R. D.; Sulignano, B.; Van Duppen, P.

    2016-06-01

    Isomeric states in 194Po and 192Po were studied at the velocity filter SHIP. The isotopes were produced in the fusion-evaporation reactions 141Pr(56Fe, p 2 n )194Po and 144Sm(51V, p 2 n )192Po . Several new γ -ray transitions were attributed to the isomers and γ -γ coincidences for both isomers were studied for the first time. The 459-keV transition earlier, tentatively proposed as de-exciting the isomeric level in 194Po, was replaced by a new 248-keV transition, and the spin of this isomer was reassigned from (11-) to (10-). The de-excitation of the (11-) isomeric level in 192Po by the 154-keV transition was confirmed and a parallel de-excitation by a 733-keV (E 3 ) transition to (8+) level of the ground-state band was suggested. Moreover, side feeding to the (4+) level of the ground-state band was proposed. The paper also discusses strengths of transitions de-exciting 11- isomers in neighboring Po and Pb isotopes.

  8. Short-lived radionuclides and early solar system chronology -- A hibonite perspective

    NASA Astrophysics Data System (ADS)

    Liu, Ming-Chang

    Examination of the 41 Ca- 41 K, 26 Al- 26 Mg, 10 Be- 10 B, oxygen and titanium iso-topic systems in 26 hibonite-bearing inclusions extracted from the CM meteorite Murchison provide important constraints for origins of short-lived radionuclides, early solar system chronology, and chemical evolution. Magnesium isotopic compositions divide these hibonite grains into two distinct populations which correlate perfectly with their mineralogy and morphology, as previously discovered by Ireland (1988): Spinel-HIBonite spherules (SHIBs) bear evidence of in-situ decay of 26 Al, whereas PLAty hibonite Crystals (PLACs) and Blue AGgregates (BAGs) either lack resolvable D 26 Mg* excesses or exhibit 26 Mg deficits by up to ~4[per thousand]. High precision, multiple collector SIMS analyses show that 6 of 7 SHIBs investigated fall on a single correlation line implying 26 Al/ 27 Al = (4.4±0.2) × 10 -5 (2s) at the time of isotopic closure, consistent with the "canonical" 26 Al abundance characteristic of internal isochrons in many calcium-aluminum-rich inclusions (CAIs). One SHIB sample exhibits D 26 Mg* corresponding to a "supra-canonical" 26 Al/ 27 Al ratio 6.3 × 10 -5 which is close to the highest ratios observed in solar system materials. Eight out of 11 26 Al-free PLAC hibonite grains record excesses of radiogenic 10 B which correlate with Be/B; the inferred initial 10 Be/ 9 Be ratio of (5.1 ± 1.4) × 10 -4 is substantially lower than the best-constrained 10 Be/ 9 Be of (8.8±0.6) × 10 -4 in a CV CAI. The data demonstrate that 10 Be cannot be used as a relative chronometer for these objects and that most of the 10 Be observed in CAIs must be produced by energetic particle irradiation of refractory dust precursors in the early solar system. The lack of 26 Al in PLAC hibonites containing Mg isotope anomalies and 10 Be indicates that significant amounts of 26 Al was not formed in the same spallogenic processes that made 10 Be in PLAC precursors. Except for few hibonite grains

  9. Sediment Dating With Short-Lived Radioisotopes In Monterey Canyon, California Imply Episodes Of Rapid Deposition And Erosion

    NASA Astrophysics Data System (ADS)

    Lorenson, T. D.; Swarzenski, P. W.; Maier, K. L.; Gwiazda, R.; Paull, C. K.; Sumner, E.; Symons, W. O.

    2015-12-01

    Submarine canyons are a major conduit for terrestrial material to the deep sea. To better constrain the timing and rates in which sediment is transported down-canyon, we collected a series of sediment cores along the axis of Monterey Canyon, and quantified mass accumulation rates using short-lived radio-isotopes. A suite of sediment cores were carefully collected perpendicular to the canyon thalweg in water depths of approximately 300m, 500m, 800m, and 1500m using a remotely operated vehicle (ROV). We choose cores that were between 60m and 75m above the canyon thalweg on canyon side bench features for correlation with moored instrument deployments. The sediment cores reveal a complex stratigraphy that includes copious bioturbation features, sand lenses, subtle erosional surfaces, subtle graded bedding, and abrupt changes sediment texture and color. Downcore excess 210Pb and 137Cs profiles imply episodic deposition and remobilization cycles on the canyon benches. Excess 210Pb activities in cores reach depths of up to 1m, implying very rapid sedimentation. Sedimentation rates vary with water depth, generally with the highest sedimentation rate in closest to land, but vary substantially on adjacent canyon benches. Preliminary results demonstrate that sediment movement within Monterey Canyon is both dynamic and episodic on human time-scales and can be reconstructed used short-lived radio-isotopes.

  10. Developments in precison mass measurements of short-lived r-process nuclei with CARIBU

    NASA Astrophysics Data System (ADS)

    Marley, S. T.; Aprahamian, A.; Mumpower, M.; Nystrom, A.; Paul, N.; Siegl, K.; Strauss, S.; Surman, R.; Clark, J. A.; Perez Galvan, A.; Savard, G.; Morgan, G.; Orford, R.

    2013-10-01

    The confluence of new radioactive beam facilities and modern precision mass spectrometry techniques now make it possible to measure masses of many neutron-rich nuclei important to nuclear structure and astrophysics. A recent mass sensitivity study (S. Brett et al., Eur. Phys. J., A 48, 184 (2012)) identified the nuclear masses that are the most influential to the final rapid-neutron capture process abundance distributions under various astrophysical scenarios. This work motivated a campaign of precision mass measurements using the Canadian Penning Trap (CPT) installed at the Californium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory. In order to measure the weakest and most short-lived (t1/2 < 150 ms) of these influential nuclei, a series of upgrades to the CARIBU and CPT systems have been developed. The implementation of these upgrades, the r-process mass measurements, and the status of CARIBU facilty will be discussed. This work performed under the auspices of NSERC, Canada, appl. # 216974, the U.S. DOE, Office of Nuclear Physics, under contracts DE-AC02-06CH11357, DE-FG02-91ER-40609, DE-FG02-98ER41086, & DE-AC52-07NA27344, and NSF Grants PHY08-22648 and PHY-106819.

  11. Fission Half Lives of Fermium Isotopes Within Skyrme Hartree-Fock Theory

    NASA Astrophysics Data System (ADS)

    Baran, A.; Staszczak, A.; Nazarewicz, W.

    Nuclear fission barriers, mass parameters and spontaneous fission half lives of fermium isotopes calculated in a framework of the Skyrme Hartree-Fock-Bogoliubov model with the SkM* force are discussed. Zero-point energy corrections in the ground state are determined for each nucleus using the Gaussian overlap approximation of the generator coordinate method and in the cranking formalism. Results of spontaneous fission half lives are compared to experimental data.

  12. FISSION HALF LIVES OF FERMIUM ISOTOPES WITHIN SKYRME HARTREE-FOCK-BOGOLIUBOV THEORY

    SciTech Connect

    Baran, A.; Staszczak, Andrzej; Nazarewicz, A.

    2011-01-01

    Nuclear fission barriers, mass parameters and spontaneous fission half lives of fermium isotopes calculated in a framework of the Skyrme Hartree-Fock-Bogoliubov model with the SkM* force are discussed. Zero-point energy corrections in the ground state are determined for each nucleus using the Gaussian overlap approximation of the generator coordinate method and in the cranking formalism. Results of spontaneous fission half lives are compared to experimental data.

  13. Short-lived and discontinuous intraplate volcanism in the South Pacific: Hot spots or extensional volcanism?

    NASA Astrophysics Data System (ADS)

    Koppers, Anthony A. P.; Staudigel, Hubert; Pringle, Malcolm S.; Wijbrans, Jan R.

    2003-10-01

    plumes cannot explain the intraplate volcanism of the South Pacific region. We argue that the observed short-lived and discontinuous intraplate volcanism has been produced by another type of hot spot-related volcanism, as opposed to the strong and continuous Hawaiian-type hot spots. Our results also indicate that other geological processes (plate tension, hotlines, faulting, wetspots, self-propagating volcanoes) may act in conjunction with hot spot volcanism in the South Pacific. In all these scenarios, intraplate volcanism has to be controlled by "broad-scale" events giving rise to multiple closely-spaced mantle plumelets, each with a distinct isotopic signature, but only briefly active and stable over geological time. It seems most likely that these plumelets originate and dissipate at very shallow mantle depths, where they may shoot off as thin plumes from the top of a "superplume" that is present in the South Pacific mantle. The absence of clear age progressions in most seamount trails and periodic flare-ups of massive intraplate volcanism in the South Pacific (such as the one in the Cretaceous and one starting 30 Myr ago) show that regional extension (caused by changes in the global plate circuit and/or the rise-and-fall of an oscillating superplume) may be driving the waxing and waning of intraplate volcanism in the South Pacific.

  14. Studies of images of short-lived events using ERTS data

    NASA Technical Reports Server (NTRS)

    Deutschman, W. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Of significance are the continued detection and analysis of such short-lived events as forest fires, oil spills, vegetation damage, volcanoes, storm ridges, and earthquakes.

  15. Production of a short-lived filament by a surge. [in solar atmosphere

    NASA Technical Reports Server (NTRS)

    Zirin, H.

    1976-01-01

    An unusual solar event is investigated in which a short-lived cloud, very much like a filament, was formed by ejecta from a large surge. The temporal evolution of this surge is described, and evidence is presented which indicates that the short-lived cloud was a bona fide filament. The energetics of this event and the mass of the surge are estimated from radio and X-ray data obtained at the onset.

  16. The production of short-lived radionuclides by new non-rotating and rotating Wolf-Rayet model stars

    NASA Astrophysics Data System (ADS)

    Arnould, M.; Goriely, S.; Meynet, G.

    2006-07-01

    Context.It has been speculated that WR winds may have contaminated the forming solar system, in particular with short-lived radionuclides (half-lives in the approximate 10^5{-}108 y range) that are responsible for a class of isotopic anomalies found in some meteoritic materials.Aims.We revisit the capability of the WR winds to eject these radionuclides using new models of single non-exploding WR stars with metallicity Z = 0.02.Methods. The earlier predictions for non-rotating WR stars are updated, and models for rotating such stars are used for the first time in this context.Results. We find that (1) rotation has no significant influence on the short-lived radionuclide production by neutron capture during the core He-burning phase, and (2) {}26{Al},{}36{Cl}, {}41{Ca}, and {}107{Pd} can be wind-ejected by a variety of WR stars at relative levels that are compatible with the meteoritic analyses for a period of free decay of around 105 y between production and incorporation into the forming solar system solid bodies.Conclusions.We confirm the previously published conclusions that the winds of WR stars have a radionuclide composition that can meet the necessary condition for them to be a possible contaminating agent of the forming solar system. Still, it remains to be demonstrated from detailed models that this is a sufficient condition for these winds to have provided a level of pollution that is compatible with the observations.

  17. Rate of resistance evolution and polymorphism in long- and short-lived hosts.

    PubMed

    Bruns, Emily; Hood, Michael E; Antonovics, Janis

    2015-02-01

    Recent theoretical work has shown that long-lived hosts are expected to evolve higher equilibrium levels of disease resistance than shorter-lived hosts, but questions of how longevity affects the rate of resistance evolution and the maintenance of polymorphism remain unanswered. Conventional wisdom suggests that adaptive evolution should occur more slowly in long-lived organisms than in short-lived organisms. However, the opposite may be true for the evolution of disease-resistance traits where exposure to disease, and therefore the strength of selection for resistance increases with longevity. In a single locus model of innate resistance to a frequency-dependent, sterilizing disease, longer lived hosts evolved resistance more rapidly than short-lived hosts. Moreover, resistance in long-lived hosts could only be polymorphic for more costly and more extreme resistance levels than short-lived hosts. The increased rate of evolution occurred in spite of longer generation times because longer-lived hosts had both a longer period of exposure to disease as well as higher disease prevalence. Qualitatively similar results were found when the model was extended to mortality-inducing diseases, or to density-dependent transmission modes. Our study shows that the evolutionary dynamics of host resistance is determined by more than just levels of resistance and cost, but is highly sensitive to the life-history traits of the host.

  18. [On the change in the isotopic composition of living beings during aging and evolution].

    PubMed

    Gladyshev, G P

    2013-01-01

    The article notes that the change in the isotopic composition of living beings during aging and in the evolution was predicted on the basis of the "principle of stability of matter". This principle was formulated by the author in the late 70's of the last century. New quantitative estimates were made, confirming the above prediction. To date, there are many studies that confirm those previously formulated approval by the author. These facts are a new confirmation of the thermodynamic theory of the origin of life, its evolution and aging of living beings.

  19. Methods to Collect, Compile, and Analyze Observed Short-lived Fission Product Gamma Data

    SciTech Connect

    Finn, Erin C.; Metz, Lori A.; Payne, Rosara F.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Pierson, Bruce D.; Ellis, Tere A.

    2011-09-29

    A unique set of fission product gamma spectra was collected at short times (4 minutes to 1 week) on various fissionable materials. Gamma spectra were collected from the neutron-induced fission of uranium, neptunium, and plutonium isotopes at thermal, epithermal, fission spectrum, and 14-MeV neutron energies. This report describes the experimental methods used to produce and collect the gamma data, defines the experimental parameters for each method, and demonstrates the consistency of the measurements.

  20. Systematic study on α-decay half-lives of Bi isotopes

    NASA Astrophysics Data System (ADS)

    Cui, J. P.; Zhang, Y. L.; Zhang, S.; Wang, Y. Z.

    2016-07-01

    Systematic calculations on α-decay half-lives of Bi isotopes are performed by using the generalized liquid drop model (GLDM) and several sets of Royer’s analytic formulas. In calculations, the α transitions include the ones of (i) ground state (g.s.) to g.s., (ii) g.s. to isomeric state (i.s.), (iii) i.s. to g.s., (iv) i.s. to i.s. According to the comparison between the calculated half-lives and the experimental data, it is found that the experimental half-lives are reproduced well by the GLDM with the cluster-like mode. This indicates that the nuclear structure details play important roles in the α-decay half-lives. In addition, it is found that the experimental half-lives are not reproduced well by these analytic formulas because the parameters are obtained by fitting the experimental half-lives of g.s. to g.s. transitions. To give better predictions on α-decay half-lives, the parameters in these formulas should be refitted by including the experimental α-transition of (ii)-(iv) mentioned above.

  1. Short-Term Coral Bleaching Is Not Recorded by Skeletal Boron Isotopes

    PubMed Central

    Schoepf, Verena; McCulloch, Malcolm T.; Warner, Mark E.; Levas, Stephen J.; Matsui, Yohei; Aschaffenburg, Matthew D.; Grottoli, Andréa G.

    2014-01-01

    Coral skeletal boron isotopes have been established as a proxy for seawater pH, yet it remains unclear if and how this proxy is affected by seawater temperature. Specifically, it has never been directly tested whether coral bleaching caused by high water temperatures influences coral boron isotopes. Here we report the results from a controlled bleaching experiment conducted on the Caribbean corals Porites divaricata, Porites astreoides, and Orbicella faveolata. Stable boron (δ11B), carbon (δ13C), oxygen (δ18O) isotopes, Sr/Ca, Mg/Ca, U/Ca, and Ba/Ca ratios, as well as chlorophyll a concentrations and calcification rates were measured on coral skeletal material corresponding to the period during and immediately after the elevated temperature treatment and again after 6 weeks of recovery on the reef. We show that under these conditions, coral bleaching did not affect the boron isotopic signature in any coral species tested, despite significant changes in coral physiology. This contradicts published findings from coral cores, where significant decreases in boron isotopes were interpreted as corresponding to times of known mass bleaching events. In contrast, δ13C and δ18O exhibited major enrichment corresponding to decreases in calcification rates associated with bleaching. Sr/Ca of bleached corals did not consistently record the 1.2°C difference in seawater temperature during the bleaching treatment, or alternatively show a consistent increase due to impaired photosynthesis and calcification. Mg/Ca, U/Ca, and Ba/Ca were affected by coral bleaching in some of the coral species, but the observed patterns could not be satisfactorily explained by temperature dependence or changes in coral physiology. This demonstrates that coral boron isotopes do not record short-term bleaching events, and therefore cannot be used as a proxy for past bleaching events. The robustness of coral boron isotopes to changes in coral physiology, however, suggests that reconstruction of

  2. Short-term coral bleaching is not recorded by skeletal boron isotopes.

    PubMed

    Schoepf, Verena; McCulloch, Malcolm T; Warner, Mark E; Levas, Stephen J; Matsui, Yohei; Aschaffenburg, Matthew D; Grottoli, Andréa G

    2014-01-01

    Coral skeletal boron isotopes have been established as a proxy for seawater pH, yet it remains unclear if and how this proxy is affected by seawater temperature. Specifically, it has never been directly tested whether coral bleaching caused by high water temperatures influences coral boron isotopes. Here we report the results from a controlled bleaching experiment conducted on the Caribbean corals Porites divaricata, Porites astreoides, and Orbicella faveolata. Stable boron (δ11B), carbon (δ13C), oxygen (δ18O) isotopes, Sr/Ca, Mg/Ca, U/Ca, and Ba/Ca ratios, as well as chlorophyll a concentrations and calcification rates were measured on coral skeletal material corresponding to the period during and immediately after the elevated temperature treatment and again after 6 weeks of recovery on the reef. We show that under these conditions, coral bleaching did not affect the boron isotopic signature in any coral species tested, despite significant changes in coral physiology. This contradicts published findings from coral cores, where significant decreases in boron isotopes were interpreted as corresponding to times of known mass bleaching events. In contrast, δ13C and δ18O exhibited major enrichment corresponding to decreases in calcification rates associated with bleaching. Sr/Ca of bleached corals did not consistently record the 1.2°C difference in seawater temperature during the bleaching treatment, or alternatively show a consistent increase due to impaired photosynthesis and calcification. Mg/Ca, U/Ca, and Ba/Ca were affected by coral bleaching in some of the coral species, but the observed patterns could not be satisfactorily explained by temperature dependence or changes in coral physiology. This demonstrates that coral boron isotopes do not record short-term bleaching events, and therefore cannot be used as a proxy for past bleaching events. The robustness of coral boron isotopes to changes in coral physiology, however, suggests that reconstruction of

  3. Alterations in oxidative, inflammatory and apoptotic events in short-lived and long-lived mice testes

    PubMed Central

    Matzkin, María Eugenia; Miquet, Johanna Gabriela; Fang, Yimin; Hill, Cristal Monique; Turyn, Daniel; Calandra, Ricardo Saúl; Bartke, Andrzej; Frungieri, Mónica Beatriz

    2016-01-01

    Aged testes undergo profound histological and morphological alterations leading to a reduced functionality. Here, we investigated whether variations in longevity affect the development of local inflammatory processes, the oxidative state and the occurrence of apoptotic events in the testis. To this aim, well-established mouse models with delayed (growth hormone releasing hormone-knockout and Ames dwarf mice) or accelerated (growth hormone-transgenic mice) aging were used. We hereby show that the testes of short-lived mice show a significant increase in cyclooxygenase 2 expression, PGD2 production, lipid peroxidation, antioxidant enzymes expression, local macrophages and TUNEL-positive germ cells numbers, and the levels of both pro-caspase-3 and cleaved caspase-3. In contrast, although the expression of antioxidant enzymes remained unchanged in testes of long-lived mice, the remainder of the parameters assessed showed a significant reduction. This study provides novel evidence that longevity confers anti-inflammatory, anti-oxidant and anti-apoptotic capacities to the adult testis. Oppositely, short-lived mice suffer testicular inflammatory, oxidative and apoptotic processes. PMID:26805572

  4. New Half-lives of r-process Zn and Ga Isotopes Measured with Electromagnetic Separation

    NASA Astrophysics Data System (ADS)

    Madurga, M.; Surman, R.; Borzov, I. N.; Grzywacz, R.; Rykaczewski, K. P.; Gross, C. J.; Miller, D.; Stracener, D. W.; Batchelder, J. C.; Brewer, N. T.; Cartegni, L.; Hamilton, J. H.; Hwang, J. K.; Liu, S. H.; Ilyushkin, S. V.; Jost, C.; Karny, M.; Korgul, A.; Królas, W.; Kuźniak, A.; Mazzocchi, C.; Mendez, A. J., II; Miernik, K.; Padgett, S. W.; Paulauskas, S. V.; Ramayya, A. V.; Winger, J. A.; Wolińska-Cichocka, M.; Zganjar, E. F.

    2012-09-01

    The β decays of neutron-rich nuclei near the doubly magic Ni78 were studied at the Holifield Radioactive Ion Beam Facility using an electromagnetic isobar separator. The half-lives of Zn82 (228±10ms), Zn83 (117±20ms), and Ga85 (93±7ms) were determined for the first time. These half-lives were found to be very different from the predictions of the global model used in astrophysical simulations. A new calculation was developed using the density functional model, which properly reproduced the new experimental values. The robustness of the new model in the Ni78 region allowed us to extrapolate data for more neutron-rich isotopes. The revised analysis of the rapid neutron capture process in low entropy environments with our new set of measured and calculated half-lives shows a significant redistribution of predicted isobaric abundances strengthening the yield of A>140 nuclei.

  5. Yields of short-lived fission products produced following {sup 235}U(n{sub th},f)

    SciTech Connect

    Tipnis, S.V.; Campbell, J.M.; Couchell, G.P.; Li, S.; Nguyen, H.V.; Pullen, D.J.; Schier, W.A.; Seabury, E.H.; England, T.R.

    1998-08-01

    Measurements of gamma-ray spectra, following the thermal neutron fission of {sup 235}U have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10thinsp000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with the recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for the cases of short-lived fission products with lifetimes of the order of fractions of a second or a few seconds. Independent yields of many of these isotopes have rather large uncertainties, some of which have been reduced by the present study. {copyright} {ital 1998} {ital The American Physical Society}

  6. Short-lived fluorescence component of DPH reports on lipid--water interface of biological membranes.

    PubMed

    Konopásek, Ivo; Vecer, Jaroslav; Strzalka, Kazimierz; Amler, Evzen

    2004-07-01

    Fluorescence measurements of 1,6-diphenyl-1,3,5-hexatriene (DPH) in large unilamellar phospholipid vesicles were performed to characterize the influence of the membrane physical properties on the short-lived lifetime component of the fluorescence decay. We have found that the short-lived component of DPH significantly shortens when the membrane undergoes a temperature-induced phase transition as it is known for the long-lived component of DPH. We induced membrane phase transitions also by alcohols, which are reported to be distributed different way in the membrane--ethanol close to the membrane-water interface and benzyl alcohol in the membrane core. A different effect of the respective alcohol on the short and long decay component was observed. Both the time-resolved fluorescence spectra of DPH taken during lipid vesicle staining and the lifetime dependences caused by changes of temperature and/or induced by the alcohols show that the short-lived fluorescence originates from the population of dye molecules distributed at the membrane-water interface.

  7. Absence of replicative senescence in cultured cells from the short-lived killifish Nothobranchius furzeri.

    PubMed

    Graf, Michael; Hartmann, Nils; Reichwald, Kathrin; Englert, Christoph

    2013-01-01

    A major challenge in age research is the absence of short-lived vertebrate model organisms. The turquoise killifish Nothobranchius furzeri has the shortest known lifespan of a vertebrate that can be bred in captivity. The short lived GRZ strain only reaches a maximum age of 3-4 months, whereas other strains (MZM) reach 6-10 months. Most importantly, the short lifespan is associated with typical signs of ageing. To find out more about possible cellular factors that might contribute to the short lifespan and to the difference in lifespan between strains, we analyzed the expression of markers for cellular senescence. Expression of Tp53, Cdkn1a and Cdkn2a/b in skin revealed no change in the short-lived GRZ but increased expression of the cell cycle inhibitors Cdkn1a and Cdkn2a/b in the long-lived MZM strain with age. This suggests that expression of distinct cell cycle inhibitors reflects rather chronological than biological age in N. furzeri. To study the relationship of organismal life span and in vitro life span of cells, we established a primary cell culture model. For both strains we demonstrate here the absence of replicative senescence as analysed by morphology, expression of Cdkn1a and Cdkn2a/b, population doubling times and γH2AFX in long-term and short-term cultured cells. We reason this to be on account of sustained telomerase activity and maintained telomeric length. Hence, we propose that differences in maximum life span of different N. furzeri strains is not reflected by differences in proliferation speed or replicative potential of the respective cultured cells.

  8. Absence of replicative senescence in cultured cells from the short-lived killifish Nothobranchius furzeri.

    PubMed

    Graf, Michael; Hartmann, Nils; Reichwald, Kathrin; Englert, Christoph

    2013-01-01

    A major challenge in age research is the absence of short-lived vertebrate model organisms. The turquoise killifish Nothobranchius furzeri has the shortest known lifespan of a vertebrate that can be bred in captivity. The short lived GRZ strain only reaches a maximum age of 3-4 months, whereas other strains (MZM) reach 6-10 months. Most importantly, the short lifespan is associated with typical signs of ageing. To find out more about possible cellular factors that might contribute to the short lifespan and to the difference in lifespan between strains, we analyzed the expression of markers for cellular senescence. Expression of Tp53, Cdkn1a and Cdkn2a/b in skin revealed no change in the short-lived GRZ but increased expression of the cell cycle inhibitors Cdkn1a and Cdkn2a/b in the long-lived MZM strain with age. This suggests that expression of distinct cell cycle inhibitors reflects rather chronological than biological age in N. furzeri. To study the relationship of organismal life span and in vitro life span of cells, we established a primary cell culture model. For both strains we demonstrate here the absence of replicative senescence as analysed by morphology, expression of Cdkn1a and Cdkn2a/b, population doubling times and γH2AFX in long-term and short-term cultured cells. We reason this to be on account of sustained telomerase activity and maintained telomeric length. Hence, we propose that differences in maximum life span of different N. furzeri strains is not reflected by differences in proliferation speed or replicative potential of the respective cultured cells. PMID:22445733

  9. Stable isotope analysis reveals whether soil-living elaterid larvae move between agricultural crops

    PubMed Central

    Schallhart, N.; Tusch, M.J.; Staudacher, K.; Wallinger, C.; Traugott, M.

    2011-01-01

    Tracking the movement of soil-living herbivores is difficult, albeit important for understanding their spatial ecology as well as for pest management. In this study the movement of Agriotes obscurus larvae between plots harbouring isotopically different plants was examined. Neither between maize and wheat nor between maize and grassland movement could be detected. These data suggest that Agriotes larvae rarely disperse between crops as long as local food supply is sufficient. Moreover, the current approach provides a new means to study the dispersal of soil invertebrates in situ. PMID:21760645

  10. Short-Term Protein Stable Isotope Probing of Microbial Communities to Associate Functions with Taxa (Invited)

    NASA Astrophysics Data System (ADS)

    Lipton, M. S.; Slysz, G. W.; Steinke, L. A.; Ward, D. M.; Klatt, C. G.; Clauss, T. R.; Purvine, S. O.; Anderson, G. A.; Payne, S. H.; Bryant, D. A.

    2013-12-01

    Determining which taxa in a community perform which functions is essential for understanding metabolite fluxes and metabolic interactions among community members. Specific taxa will alter their metabolism in order to acclimate to changing environmental factors such as light through the diel cycle, changing temperature and other factors. Monitoring which proteins are being expressed, and the quantitative protein expression patterns in the individual taxa as a response to external stimuli is key to understanding these mechanisms. Protein stable isotope probing (Pro-SIP) has strong potential for revealing key metabolizing taxa in complex microbial communities. In Pro-SIP studies, label incorporation is determined by the extent of the change in the isotopic profile of peptides when measured by mass spectrometry. While most Pro-SIP work to date has been performed under controlled laboratory conditions to allow extensive isotope labeling of the target organism(s), these techniques have not been applied to short term in situ studies due to the small degree of partial labeling of the proteins. We have applied Pro-SIP to study the assimilation of a labeled substrate into proteins to determine which taxa are responsible for sequestration of dissolved inorganic carbon in microbial mats associated with the alkaline siliceous hot springs of Yellowstone National Park. This community is fueled by sunlight as it transitions from dark to light; the aim was to understand the light-dependent pathway of inorganic carbon incorporation into different taxa during the early morning hours when the mat was in low light and anoxic. Each mat sample was incubated with 13C-bicarbonate for 3 h. Substrate assimilation was determined through standard proteomic techniques along with the use of SIPPER, a collection of algorithms that sensitively measure small changes in peptide isotopic patterns, allowing the determination of which taxa assimilated the substrate during this period. For the

  11. Short-lived K2S Molecules in Superionic Potassium Sulfide

    NASA Astrophysics Data System (ADS)

    Okeya, Yusuke; Tsumuraya, Kazuo

    2015-03-01

    The first principles molecular dynamics method allows us to elucidate the formation of short-lived K2S molecular states in superionic potassium sulfide. The covalent and the Coulomb bonds exist between the ionized mobile potassiums and the ionized immobile sulfurs. Both the bonds induces indirect covalent and indirect Coulomb attractions between the di-interstitial potassiums on the mid-sulfurs, which forms the short-lived K2S molecular states. The covalent electron density also exists between short-lived potassium dimers. The three attractions reduce Haven's ratios of the potassiums in the conductor. The molecule formation indicates the electronic state of the conductor is intermediate between the ionic and covalent crystals. The absence of the long-lived potassium dimers implies a failure of the caterpillar diffusion model or the Frenkel-Kontorova chain model for the superionic diffusion of the potassiums in the sulfide. The incompletely ionized cations and anions reduce the Coulomb attractions between them which induces the sublattice melting of smaller size of the potassiums than the sulfurs.

  12. Dicer Regulates the Balance of Short-Lived Effector and Long-Lived Memory CD8 T Cell Lineages

    PubMed Central

    Baumann, Florian M.; Yuzefpolskiy, Yevgeniy; Sarkar, Surojit; Kalia, Vandana

    2016-01-01

    MicroRNAs constitute a major post-transcriptional mechanism for controlling protein expression, and are emerging as key regulators during T cell development and function. Recent reports of augmented CD8 T cell activation and effector differentiation, and aberrant migratory properties upon ablation of Dicer/miRNAs in naïve cells have established a regulatory role of miRNAs during priming. Whether miRNAs continue to exert similar functions or are dispensable during later stages of CD8 T cell expansion and memory differentiation remains unclear. Here, we report a critical role of Dicer/miRNAs in regulating the balance of long-lived memory and short-lived terminal effector fates during the post-priming stages when CD8 T cells undergo clonal expansion to generate a large cytotoxic T lymphocyte (CTL) pool and subsequently differentiate into a quiescent memory state. Conditional ablation of Dicer/miRNAs in early effector CD8 T cells following optimal activation and expression of granzyme B, using unique dicerfl/fl gzmb-cre mice, led to a strikingly diminished peak effector size relative to wild-type antigen-specific cells in the same infectious milieu. Diminished expansion of Dicer-ablated CD8 T cells was associated with lack of sustained antigen-driven proliferation and reduced accumulation of short-lived effector cells. Additionally, Dicer-ablated CD8 T cells exhibited more pronounced contraction after pathogen clearance and comprised a significantly smaller proportion of the memory pool, despite significantly higher proportions of CD127Hi memory precursors at the effector peak. Combined with previous reports of dynamic changes in miRNA expression as CD8 T cells differentiate from naïve to effector and memory states, these findings support distinct stage-specific roles of miRNA-dependent gene regulation during CD8 T cell differentiation. PMID:27627450

  13. Dicer Regulates the Balance of Short-Lived Effector and Long-Lived Memory CD8 T Cell Lineages.

    PubMed

    Baumann, Florian M; Yuzefpolskiy, Yevgeniy; Sarkar, Surojit; Kalia, Vandana

    2016-01-01

    MicroRNAs constitute a major post-transcriptional mechanism for controlling protein expression, and are emerging as key regulators during T cell development and function. Recent reports of augmented CD8 T cell activation and effector differentiation, and aberrant migratory properties upon ablation of Dicer/miRNAs in naïve cells have established a regulatory role of miRNAs during priming. Whether miRNAs continue to exert similar functions or are dispensable during later stages of CD8 T cell expansion and memory differentiation remains unclear. Here, we report a critical role of Dicer/miRNAs in regulating the balance of long-lived memory and short-lived terminal effector fates during the post-priming stages when CD8 T cells undergo clonal expansion to generate a large cytotoxic T lymphocyte (CTL) pool and subsequently differentiate into a quiescent memory state. Conditional ablation of Dicer/miRNAs in early effector CD8 T cells following optimal activation and expression of granzyme B, using unique dicerfl/fl gzmb-cre mice, led to a strikingly diminished peak effector size relative to wild-type antigen-specific cells in the same infectious milieu. Diminished expansion of Dicer-ablated CD8 T cells was associated with lack of sustained antigen-driven proliferation and reduced accumulation of short-lived effector cells. Additionally, Dicer-ablated CD8 T cells exhibited more pronounced contraction after pathogen clearance and comprised a significantly smaller proportion of the memory pool, despite significantly higher proportions of CD127Hi memory precursors at the effector peak. Combined with previous reports of dynamic changes in miRNA expression as CD8 T cells differentiate from naïve to effector and memory states, these findings support distinct stage-specific roles of miRNA-dependent gene regulation during CD8 T cell differentiation. PMID:27627450

  14. Properties of short-living ball lightning produced in the laboratory

    NASA Astrophysics Data System (ADS)

    Egorov, A. I.; Stepanov, S. I.

    2008-06-01

    An experimental setup for highly reproducible generation of artificial ball lightnings is implemented. Thousands of floating glowing plasmoids 12-20 cm in diameter are produced. Research facilities for studying the plasmoids are developed. It is found that short-lived ball lightnings live for about 1 s and carry an electric charge. The lightnings are shown to have a complex structure: a central kernel containing a rich variety of hydrated ions and aerosol of decay products is surrounded by a thin negatively charged shell.

  15. Cross Sections Needed for the Interpretation of Long-Lived and Short-Lived Cosmogenic Nuclide Production in Extraterrestrial Materials

    NASA Astrophysics Data System (ADS)

    Sisterson, J. M.; Beverding, A.; Kim, K. J.; Englert, P. A. J.; Jull, A. J. T.; Donahue, D. J.; Cloudt, S.; Castaneda, C.; Vincent, J.; Caffee, M. W.; Osazuwa, C. O.; Reedy, R. C.

    1995-09-01

    Radionuclides produced by cosmic rays in extraterrestrial materials archive information that can be used to determine cosmic-ray fluxes and to study the history of the irradiated object. Long-lived radionuclides give information about the last ~5 Myr; short-lived radionuclides give information about recent events. To calculate the solar cosmic ray (SCR) flux from measured depth profiles for cosmogenic radionuclides produced in lunar rocks, accurate and precise cross section values for the production of these radionuclides from all relevant elements are needed. About 98% of SCR and ~87% of galactic cosmic rays (GCR) falling on extraterrestrial materials are protons. Cross section measurements were made using three proton accelerators to cover the energy range ~20 - 500 MeV. Thin target techniques used in the irradiations minimized the number of protons scattered out of the stack and the neutron production within the stack. After irradiation, the short-lived radionuclides e.g. 22Na, 7Be, 24Na, 54Mn, and 56Co were determined using gamma-ray spectroscopy. 14C, 10Be, and 26Al were determined using Accelerator Mass Spectrometry. Our main objective is to measure the production cross sections of long-lived radionuclides. We have reported new cross section values for making 10Be from O and 14C from O, Mg, Al, Si, Fe, and Ni [1,2]. Using these new results, better estimates for the solar proton flux over several time periods in the past were determined [3]. However, no single value for the SCR flux could explain the measured data from different time periods. Further cross section measurements are being made to verify that the values used in these estimates were accurate. Irradiations designed to give good cross section measurements for long-lived radionuclides also give good cross section measurements for short-lived radionuclides. Results will be presented for proton production cross sections of 22Na from Mg, Al and Si, and 54Mn and 56Co from Fe and Ni; some values at low

  16. First results using a new technology for measuring masses of very short-lived nuclides with very high accuracy: The MISTRAL program at ISOLDE

    SciTech Connect

    Monsanglant, C.; Audi, G.; Conreur, G.; Cousin, R.; Doubre, H.; Jacotin, M.; Henry, S.; Kepinski, J.-F.; Lunney, D.; Saint Simon, M. de; Thibault, C.; Toader, C.; Bollen, G.; Lebee, G.; Scheidenberger, C.; Borcea, C.; Duma, M.; Kluge, H.-J.; Le Scornet, G.

    1999-11-16

    MISTRAL is an experimental program to measure masses of very short-lived nuclides (T{sub 1/2} down to a few ms), with a very high accuracy (a few 10{sup -7}). There were three data taking periods with radioactive beams and 22 masses of isotopes of Ne, Na, Mg, Al, K, Ca, and Ti were measured. The systematic errors are now under control at the level of 8x10{sup -7}, allowing to come close to the expected accuracy. Even for the very weakly produced {sup 30}Na (1 ion at the detector per proton burst), the final accuracy is 7x10{sup -7}.

  17. Multicolor live-cell chemical imaging by isotopically edited alkyne vibrational palette.

    PubMed

    Chen, Zhixing; Paley, Daniel W; Wei, Lu; Weisman, Andrew L; Friesner, Richard A; Nuckolls, Colin; Min, Wei

    2014-06-01

    Vibrational imaging such as Raman microscopy is a powerful technique for visualizing a variety of molecules in live cells and tissues with chemical contrast. Going beyond the conventional label-free modality, recent advance of coupling alkyne vibrational tags with stimulated Raman scattering microscopy paves the way for imaging a wide spectrum of alkyne-labeled small biomolecules with superb sensitivity, specificity, resolution, biocompatibility, and minimal perturbation. Unfortunately, the currently available alkyne tag only processes a single vibrational "color", which prohibits multiplex chemical imaging of small molecules in a way that is being routinely practiced in fluorescence microscopy. Herein we develop a three-color vibrational palette of alkyne tags using a (13)C-based isotopic editing strategy. We first synthesized (13)C isotopologues of EdU, a DNA metabolic reporter, by using the newly developed alkyne cross-metathesis reaction. Consistent with theoretical predictions, the mono-(13)C ((13)C≡(12)C) and bis-(13)C ((13)C≡(13)C) labeled alkyne isotopologues display Raman peaks that are red-shifted and spectrally resolved from the originally unlabeled ((12)C≡(12)C) alkynyl probe. We further demonstrated three-color chemical imaging of nascent DNA, RNA, and newly uptaken fatty-acid in live mammalian cells with a simultaneous treatment of three different isotopically edited alkynyl metabolic reporters. The alkyne vibrational palette presented here thus opens up multicolor imaging of small biomolecules, enlightening a new dimension of chemical imaging.

  18. Laboratory breeding of the short-lived annual killifish Nothobranchius furzeri.

    PubMed

    Polačik, Matej; Blažek, Radim; Reichard, Martin

    2016-08-01

    Turquoise killifish, Nothobranchius furzeri, have an intrinsically short life span, with a median life span of <6 months and a maximum (90%) life span of 9 months. This short life span, which is unique among vertebrates, evolved naturally and has resulted in N. furzeri becoming a widely used laboratory model species in aging research and other disciplines. Here, we describe a protocol for the maintenance and breeding of the species under laboratory conditions. We provide details for egg incubation, hatching, everyday care of juvenile and adult fish, breeding and treatment of most common diseases. Emphasis is given to the fact that the requirements of N. furzeri substantially differ from those of other fish model taxa; N. furzeri live brief lives and in nature undergo nonaquatic embryo development, with consequences for their laboratory culture. PMID:27388556

  19. Efficient adsorption of waterborne short-lived radon decay products by glass fiber filters.

    PubMed

    von Philipsborn, H

    1997-02-01

    Glass fiber filters of a certain brand were found to be very efficient (retention > 95%) for adsorption of short-lived radon decay products during filtration of water. Carrier-free samples are obtained in a convenient geometry for efficient gross beta counting. Adsorption of "hot atoms" is not disturbed by the presence of "cold" lead ions. Approximate radioactive equilibrium between radon and its short-lived decay products may or may not exist in water at the source, but does exist after 3 h in PET bottles. These bottles are shown to be gas-tight for radon. Calibration of activity concentration in Bq L(-1) (radon gas concentration approximately equilibrium equivalent radon concentration) was performed by several standard procedures. Limit of detection is 2 Bq L(-1) within 10 min (total time) or 10 Bq L(-1) within 5 min for a net signal of 5 times standard deviation.

  20. Laboratory breeding of the short-lived annual killifish Nothobranchius furzeri.

    PubMed

    Polačik, Matej; Blažek, Radim; Reichard, Martin

    2016-08-01

    Turquoise killifish, Nothobranchius furzeri, have an intrinsically short life span, with a median life span of <6 months and a maximum (90%) life span of 9 months. This short life span, which is unique among vertebrates, evolved naturally and has resulted in N. furzeri becoming a widely used laboratory model species in aging research and other disciplines. Here, we describe a protocol for the maintenance and breeding of the species under laboratory conditions. We provide details for egg incubation, hatching, everyday care of juvenile and adult fish, breeding and treatment of most common diseases. Emphasis is given to the fact that the requirements of N. furzeri substantially differ from those of other fish model taxa; N. furzeri live brief lives and in nature undergo nonaquatic embryo development, with consequences for their laboratory culture.

  1. Inductively coupled plasma mass spectrometry for stable isotope metabolic tracer studies of living systems

    SciTech Connect

    Luong, E.

    1999-05-10

    This dissertation focuses on the development of methods for stable isotope metabolic tracer studies in living systems using inductively coupled plasma single and dual quadrupole mass spectrometers. Sub-nanogram per gram levels of molybdenum (Mo) from human blood plasma are isolated by the use of anion exchange alumina microcolumns. Million-fold more concentrated spectral and matrix interferences such as sodium, chloride, sulfate, phosphate, etc. in the blood constituents are removed from the analyte. The recovery of Mo from the alumina column is 82 {+-} 5% (n = 5). Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is utilized for the quantitative ultra-trace concentration determination of Mo in bovine and human blood samples. The average Mo concentration in reference bovine serum determined by this method is 10.2 {+-} 0.4 ng/g, while the certified value is 11.5 {+-} 1.1 ng/g (95% confidence interval). The Mo concentration of one pool of human blood plasma from two healthy male donors is 0.5 {+-} 0.1 ng/g. The inductively coupled plasma twin quadrupole mass spectrometer (ICP-TQMS) is used to measure the carbon isotope ratio from non-volatile organic compounds and bio-organic molecules to assess the ability as an alternative analytical method to gas chromatography combustion isotope ratio mass spectrometry (GC-combustion-IRMS). Trytophan, myoglobin, and {beta}-cyclodextrin are chosen for the study, initial observation of spectral interference of {sup 13}C{sup +} with {sup 12}C{sup 1}H{sup +} comes from the incomplete dissociation of myoglobin and/or {beta}-cyclodextrin.

  2. Have we underestimated the role of short-lived chlorine compounds in ozone depletion?

    NASA Astrophysics Data System (ADS)

    Oram, David; Laube, Johannes; Sturges, Bill; Gooch, Lauren; Leedham, Emma; Ashfold, Matthew; Pyle, John; Abu Samah, Azizan; Moi Phang, Siew; Ou-Yang, Chang-Feng; Lin, Neng-Huei; Wang, Jia-Lin; Brenninkmeijer, Carl

    2015-04-01

    In recent years much attention has been focussed on the potential of bromine-containing VSLS (very short lived substances) to contribute to stratospheric ozone depletion. This is primarily due to the large observed discrepancy between the measured inorganic bromine in the stratosphere and the amount of bromine available from known, longer lived sources gases (halons and CH3Br). In contrast, the role of very short-lived chlorine compounds (VSLS-CL) has been considered trivial because they contribute only a few percent to the total organic chlorine in the troposphere, the majority of which is supplied by long-lived compounds such as the CFCs, HCFCs, methyl chloroform and carbon tetrachloride. However recent evidence shows that one VSLS-Cl, dichloromethane (CH2Cl2) has increased by 60% over the past decade (WMO, 2014) and has already begun to offset the long-term decline in stratospheric chlorine loading caused by the reduction in emissions of substances controlled by the Montreal Protocol. We will present new VSLS-Cl measurements from recent ground-based and aircraft campaigns in SE Asia where we have observed dramatic enhancements in a number of VSLS-Cl, including CH2Cl2. Furthermore we will demonstrate how pollution from China and the surrounding region can rapidly, and regularly, be transported across the South China Sea and subsequently uplifted to altitudes of 11-12 km, the region close to the lower TTL. This process occurs frequently during the winter monsoon season and could represent a fast and efficient mechanism for transporting short-lived compounds, and other pollutants, to the lower stratosphere.

  3. Short-lived nuclides in hibonite grains from Murchison: evidence for solar system evolution.

    PubMed

    Marhas, K K; Goswami, J N; Davis, A M

    2002-12-13

    Records of now-extinct short-lived nuclides in meteorites provide information about the formation and evolution of the solar system. We have found excess 10B that we attribute to the decay of short-lived 10Be (half-life 1.5 million years) in hibonite grains from the Murchison meteorite. The grains show no evidence of decay of two other short-lived nuclides-26Al (half-life 700,000 years) and 41Ca (half-life 100,000 years)-that may be present in early solar system solids. One plausible source of the observed 10Be is energetic particle irradiation of material in the solar nebula. An effective irradiation dose of approximately 2 x 10(18) protons per square centimeter with a kinetic energy of >/=10 megaelectronvolts per atomic mass unit can explain our measurements. The presence of 10Be, coupled with the absence of 41Ca and 26Al, may rule out energetic particle irradiation as the primary source of 41Ca and 26Al present in some early solar system solids and strengthens the case of a stellar source for 41Ca and 26Al.

  4. Corrections for the combined effects of decay and dead time in live-timed counting of short-lived radionuclides.

    PubMed

    Fitzgerald, R

    2016-03-01

    Studies and calibrations of short-lived radionuclides, for example (15)O, are of particular interest in nuclear medicine. Yet counting experiments on such species are vulnerable to an error due to the combined effect of decay and dead time. Separate decay corrections and dead-time corrections do not account for this issue. Usually counting data are decay-corrected to the start time of the count period, or else instead of correcting the count rate, the mid-time of the measurement is used as the reference time. Correction factors are derived for both those methods, considering both extending and non-extending dead time. Series approximations are derived here and the accuracy of those approximations are discussed. PMID:26682893

  5. Corrections for the combined effects of decay and dead time in live-timed counting of short-lived radionuclides.

    PubMed

    Fitzgerald, R

    2016-03-01

    Studies and calibrations of short-lived radionuclides, for example (15)O, are of particular interest in nuclear medicine. Yet counting experiments on such species are vulnerable to an error due to the combined effect of decay and dead time. Separate decay corrections and dead-time corrections do not account for this issue. Usually counting data are decay-corrected to the start time of the count period, or else instead of correcting the count rate, the mid-time of the measurement is used as the reference time. Correction factors are derived for both those methods, considering both extending and non-extending dead time. Series approximations are derived here and the accuracy of those approximations are discussed.

  6. Classification of short-lived objects using an interactive adaptable assistance system

    NASA Astrophysics Data System (ADS)

    El Bekri, Nadia; Angele, Susanne; Peinsipp-Byma, Elisabeth

    2015-05-01

    "Although we know that it is not a familiar object, after a while we can say what it resembles". The core task of an aerial image analyst is to recognize different object types based on certain clearly classified characteristics from aerial or satellite images. An interactive recognition assistance system compares selected features with a fixed set of reference objects (core data set). Therefore it is mainly designed to evaluate durable single objects like a specific type of ship or vehicle. Aerial image analysts on missions realized a changed warfare over the time. The task was not anymore to classify and thereby recognize a single durable object. The problem was that they had to classify strong variable objects and the reference set did not match anymore. In order to approach this new scope we introduce a concept to a further development of the interactive assistance system to be able to handle also short-lived, not clearly classifiable and strong variable objects like for example dhows. Dhows are the type of ships that are often used during pirate attacks at the coast of West Africa. Often these ships were build or extended by the pirates themselves. They follow no particular pattern as the standard construction of a merchant ship. In this work we differ between short-lived and durable objects. The interactive adaptable assistance system is supposed to assist image analysts with the classification of objects, which are new and not listed in the reference set of objects yet. The human interaction and perception is an important factor in order to realize this task and achieve the goal of recognition. Therefore we had to model the possibility to classify short-lived objects with appropriate procedures taking into consideration all aspects of short-lived objects. In this paper we will outline suitable measures and the possibilities to categorize short-lived objects via simple basic shapes as well as a temporary data storage concept for shortlived objects. The

  7. Short-lived positron emitters in beam-on PET imaging during proton therapy

    NASA Astrophysics Data System (ADS)

    Dendooven, P.; Buitenhuis, H. J. T.; Diblen, F.; Heeres, P. N.; Biegun, A. K.; Fiedler, F.; van Goethem, M.-J.; van der Graaf, E. R.; Brandenburg, S.

    2015-12-01

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of 10C, T1/2  =  19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12N (T1/2  =  11 ms) on carbon (9% of 11C), 29P (T1/2  =  4.1 s) on phosphorus (20% of 30P) and 38mK (T1/2  =  0.92 s) on calcium (113% of 38gK). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, 12N dominates up to 70 s. On bone tissue, 12N dominates over 15O during the first 8-15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of 12N PET counts, we conclude that, for any tissue, 12N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of 12N PET imaging is discussed.

  8. Demography of short-tailed shrew populations living on polychlorinated biphenyl-contaminated sites.

    PubMed

    Boonstra, Rudy; Bowman, Lanna

    2003-06-01

    In ecological risk assessment, a key necessity is to understand how contaminants known to have negative impact on laboratory mammals affect the population demography of mammals living in their natural environment. We examined the demography of six local populations of the short-tailed shrew (Blarina brevicauda) living in eastern deciduous forest palustrine habitat along the Housatonic River (MA, USA) on soils contaminated with a range of polychlorinated biphenyl (PCB) concentrations (1.5-38.3 ppm). The objective of the study was to assess whether PCBs adversely affect the population demography of these small mammals living in their natural environment. Blarina were selected for study because they would be expected to readily bioaccumulate PCBs from the soil. Populations were intensively live trapped on 1-ha grids from spring to autumn 2001. There was no relationship between any demographic parameter and PCB soil concentrations. Densities were high (usually exceeding 20/ha, and on two grids exceeded 60/ha in summer); survival was good (typically 60-75% per 30 d); and sex ratio, reproduction rates, growth rates, and body mass were within the ranges reported in the literature. Thus, these shrew populations showed no detectable impact on their population demography from living on PCB-contaminated sites.

  9. Demography of short-tailed shrew populations living on polychlorinated biphenyl-contaminated sites.

    PubMed

    Boonstra, Rudy; Bowman, Lanna

    2003-06-01

    In ecological risk assessment, a key necessity is to understand how contaminants known to have negative impact on laboratory mammals affect the population demography of mammals living in their natural environment. We examined the demography of six local populations of the short-tailed shrew (Blarina brevicauda) living in eastern deciduous forest palustrine habitat along the Housatonic River (MA, USA) on soils contaminated with a range of polychlorinated biphenyl (PCB) concentrations (1.5-38.3 ppm). The objective of the study was to assess whether PCBs adversely affect the population demography of these small mammals living in their natural environment. Blarina were selected for study because they would be expected to readily bioaccumulate PCBs from the soil. Populations were intensively live trapped on 1-ha grids from spring to autumn 2001. There was no relationship between any demographic parameter and PCB soil concentrations. Densities were high (usually exceeding 20/ha, and on two grids exceeded 60/ha in summer); survival was good (typically 60-75% per 30 d); and sex ratio, reproduction rates, growth rates, and body mass were within the ranges reported in the literature. Thus, these shrew populations showed no detectable impact on their population demography from living on PCB-contaminated sites. PMID:12785599

  10. A new methodology involving stable isotope tracer to compare short- and long- term selenium mobility in soils

    NASA Astrophysics Data System (ADS)

    Tolu, Julie; Thiry, Yves; Potin-gautier, Martine; Le hécho, Isabelle; Bueno, Maïté

    2013-04-01

    Selenium is an element of environmental concern given its dual beneficial and toxic character to animal and human health. Its radioactive isotope 79Se, a fission product of 235U, is considered critical in safety assessment of nuclear waste repositories in case of leakage and hypothetical soil contamination. Therefore, Se species transformations and interactions with soil components have to be clearly understood to predict its dispersion in the biosphere (e.g., accumulation in soils, migration to waters, transfer to living organisms). While natural Se interactions with soils run over centuries to millennia time scales, transformations and partitioning are generally studied with short-term experiments (often inferior to 1 month) after Se addition. The influence of slower, long-term processes involved in Se speciation and mobility in soils is thus not properly accounted for. We tested if using ambient Se would be relevant for long-term risk assessment while added Se would be more representative of short-term contamination impact. For that purpose, we developed a new methodology to trace the differential reactivity of ambient and spiked Se at trace level (µg kg-1) in soils. It combined the use of a stable isotopically enriched tracer with our previous published analytical method based on specific extractions and HPLC-ICP-MS to determine trace Se species partition in different soil phases. Given that soil extracts contains very high concentrations of various elements interfering Se (e.g., Fe, Cl, Br), the ICP-MS parameters and mathematical corrections were optimized to cope with such interferences. Following optimization, three correct and accurate (<2%) isotope ratios were obtained with 77Se, 78Se, 80Se and 82Se. The optimized method was then applied to an arable and a forest soil submitted to an aging process (drying/wetting cycles) during three months, to which 77Se(IV) was previously added. The results showed that ambient Se was at steady state in terms of water

  11. Cohort variation, climate effects and population dynamics in a short-lived lizard.

    PubMed

    Le Galliard, Jean François; Marquis, Olivier; Massot, Manuel

    2010-11-01

    1. Demographic theory and empirical studies indicate that cohort variation in demographic traits has substantial effects on population dynamics of long-lived vertebrates but cohort effects have been poorly investigated in short-lived species. 2. Cohort effects were quantified in the common lizard (Zootoca vivipara Jacquin 1787), a short-lived ectothermic vertebrate, for body size, reproductive traits and age-specific survival with mark-recapture data collected from 1989 to 2005 in two wetlands. We assessed cohort variation and covariation in demographic traits, tested the immediate and delayed effects of climate conditions (temperature and rainfall), and predicted consequences for population growth. 3. Most demographic traits exhibited cohort variation, but this variation was stronger for juvenile growth and survival, sub-adult survival and breeding phenology than for other traits. 4. Cohort variation was partly explained by a web of immediate and delayed effects of climate conditions. Rainfall and temperature influenced distinct life-history traits and the periods of gestation and early juvenile life were critical stages for climate effects. 5. Cohort covariation between demographic traits was usually weak, apart from a negative correlation between juvenile and sub-adult body growth suggesting compensatory responses. An age-structured population model shows that cohort variation influences population growth mainly through direct numerical effects of survival variation early in life. 6. An understanding of cohort effects is necessary to predict critical life stages and climatic determinants of population dynamics, and therefore demographic responses to future climate warming.

  12. Dealing with uncertainty: Response-resilient climate change mitigation polices for long-lived and short-lived climate pollutants

    NASA Astrophysics Data System (ADS)

    Millar, R.; Boneham, J.; Hepburn, C.; Allen, M. R.

    2015-12-01

    Climate change solutions are subject to many inherent uncertainties. One of the most important is the uncertainty over the magnitude of the physical response of the climate system to external forcing. The risk of extremely large responses to forcing, so called "fat-tail" outcomes, cannot be ruled out from the latest science and offer profound challenges when creating policies that aim to meet a specific target of global temperature change. This study offers examples of how mitigation policies can be made resilient to this uncertainty in the physical climate response via indexing policies against an attributable anthropogenic warming index (the magnitude of the observed global mean warming that is can be traced to human activities), the AWI, instead of against time directly. We show that indexing policy measures that influence the total stock of carbon in the atmosphere (such as the fraction of extracted carbon sequestered) against the AWI can largely eliminate the risk of missing the specified warming goal due to unexpectedly large climate responses as well as the risk of costly over-mitigation if the physical response turned out to be lower than expected. We offer further examples of how this methodology can be expanded to include short-lived climate pollutants as well as long-lived carbon dioxide. Indexing policies against the AWI can have important consequences for the actions of governments acting to design national climate mitigation policies as well as private sector investors looking to incentivise the transition to a climate-stable economy. We conclude with some thoughts on how these indexes can help focus attention on the long-term perspective that is consistent with the conclusions of the latest climate science on what is required to ultimately stabilise the global climate system.

  13. 182Hf–182W age dating of a 26Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System

    PubMed Central

    Holst, Jesper C.; Olsen, Mia B.; Paton, Chad; Nagashima, Kazuhide; Schiller, Martin; Wielandt, Daniel; Larsen, Kirsten K.; Connelly, James N.; Jørgensen, Jes K.; Krot, Alexander N.; Nordlund, Åke; Bizzarro, Martin

    2013-01-01

    Refractory inclusions [calcium–aluminum-rich inclusions, (CAIs)] represent the oldest Solar System solids and provide information regarding the formation of the Sun and its protoplanetary disk. CAIs contain evidence of now extinct short-lived radioisotopes (e.g., 26Al, 41Ca, and 182Hf) synthesized in one or multiple stars and added to the protosolar molecular cloud before or during its collapse. Understanding how and when short-lived radioisotopes were added to the Solar System is necessary to assess their validity as chronometers and constrain the birthplace of the Sun. Whereas most CAIs formed with the canonical abundance of 26Al corresponding to 26Al/27Al of ∼5 × 10−5, rare CAIs with fractionation and unidentified nuclear isotope effects (FUN CAIs) record nucleosynthetic isotopic heterogeneity and 26Al/27Al of <5 × 10−6, possibly reflecting their formation before canonical CAIs. Thus, FUN CAIs may provide a unique window into the earliest Solar System, including the origin of short-lived radioisotopes. However, their chronology is unknown. Using the 182Hf–182W chronometer, we show that a FUN CAI recording a condensation origin from a solar gas formed coevally with canonical CAIs, but with 26Al/27Al of ∼3 × 10−6. The decoupling between 182Hf and 26Al requires distinct stellar origins: steady-state galactic stellar nucleosynthesis for 182Hf and late-stage contamination of the protosolar molecular cloud by a massive star(s) for 26Al. Admixing of stellar-derived 26Al to the protoplanetary disk occurred during the epoch of CAI formation and, therefore, the 26Al–26Mg systematics of CAIs cannot be used to define their formation interval. In contrast, our results support 182Hf homogeneity and chronological significance of the 182Hf–182W clock. PMID:23671077

  14. 182Hf-182W age dating of a 26Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System.

    PubMed

    Holst, Jesper C; Olsen, Mia B; Paton, Chad; Nagashima, Kazuhide; Schiller, Martin; Wielandt, Daniel; Larsen, Kirsten K; Connelly, James N; Jørgensen, Jes K; Krot, Alexander N; Nordlund, Ake; Bizzarro, Martin

    2013-05-28

    Refractory inclusions [calcium-aluminum-rich inclusions, (CAIs)] represent the oldest Solar System solids and provide information regarding the formation of the Sun and its protoplanetary disk. CAIs contain evidence of now extinct short-lived radioisotopes (e.g., (26)Al, (41)Ca, and (182)Hf) synthesized in one or multiple stars and added to the protosolar molecular cloud before or during its collapse. Understanding how and when short-lived radioisotopes were added to the Solar System is necessary to assess their validity as chronometers and constrain the birthplace of the Sun. Whereas most CAIs formed with the canonical abundance of (26)Al corresponding to (26)Al/(27)Al of ∼5 × 10(-5), rare CAIs with fractionation and unidentified nuclear isotope effects (FUN CAIs) record nucleosynthetic isotopic heterogeneity and (26)Al/(27)Al of <5 × 10(-6), possibly reflecting their formation before canonical CAIs. Thus, FUN CAIs may provide a unique window into the earliest Solar System, including the origin of short-lived radioisotopes. However, their chronology is unknown. Using the (182)Hf-(182)W chronometer, we show that a FUN CAI recording a condensation origin from a solar gas formed coevally with canonical CAIs, but with (26)Al/(27)Al of ∼3 × 10(-6). The decoupling between (182)Hf and (26)Al requires distinct stellar origins: steady-state galactic stellar nucleosynthesis for (182)Hf and late-stage contamination of the protosolar molecular cloud by a massive star(s) for (26)Al. Admixing of stellar-derived (26)Al to the protoplanetary disk occurred during the epoch of CAI formation and, therefore, the (26)Al-(26)Mg systematics of CAIs cannot be used to define their formation interval. In contrast, our results support (182)Hf homogeneity and chronological significance of the (182)Hf-(182)W clock. PMID:23671077

  15. 182Hf-182W age dating of a 26Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System.

    PubMed

    Holst, Jesper C; Olsen, Mia B; Paton, Chad; Nagashima, Kazuhide; Schiller, Martin; Wielandt, Daniel; Larsen, Kirsten K; Connelly, James N; Jørgensen, Jes K; Krot, Alexander N; Nordlund, Ake; Bizzarro, Martin

    2013-05-28

    Refractory inclusions [calcium-aluminum-rich inclusions, (CAIs)] represent the oldest Solar System solids and provide information regarding the formation of the Sun and its protoplanetary disk. CAIs contain evidence of now extinct short-lived radioisotopes (e.g., (26)Al, (41)Ca, and (182)Hf) synthesized in one or multiple stars and added to the protosolar molecular cloud before or during its collapse. Understanding how and when short-lived radioisotopes were added to the Solar System is necessary to assess their validity as chronometers and constrain the birthplace of the Sun. Whereas most CAIs formed with the canonical abundance of (26)Al corresponding to (26)Al/(27)Al of ∼5 × 10(-5), rare CAIs with fractionation and unidentified nuclear isotope effects (FUN CAIs) record nucleosynthetic isotopic heterogeneity and (26)Al/(27)Al of <5 × 10(-6), possibly reflecting their formation before canonical CAIs. Thus, FUN CAIs may provide a unique window into the earliest Solar System, including the origin of short-lived radioisotopes. However, their chronology is unknown. Using the (182)Hf-(182)W chronometer, we show that a FUN CAI recording a condensation origin from a solar gas formed coevally with canonical CAIs, but with (26)Al/(27)Al of ∼3 × 10(-6). The decoupling between (182)Hf and (26)Al requires distinct stellar origins: steady-state galactic stellar nucleosynthesis for (182)Hf and late-stage contamination of the protosolar molecular cloud by a massive star(s) for (26)Al. Admixing of stellar-derived (26)Al to the protoplanetary disk occurred during the epoch of CAI formation and, therefore, the (26)Al-(26)Mg systematics of CAIs cannot be used to define their formation interval. In contrast, our results support (182)Hf homogeneity and chronological significance of the (182)Hf-(182)W clock.

  16. Inter-laboratory comparisons of short-lived gamma-emitting radionuclides in nuclear reactor water.

    PubMed

    Klemola, S K

    2008-01-01

    Inter-laboratory comparisons of gamma-emitting nuclides in nuclear power plant coolant water have been carried out in Finland since 1994. The reactor water samples are taken and prepared by one of the two nuclear power plants and delivered to the participants. Since all the participants get their sample within just a few hours it has been possible to analyse and compare results of nuclides with half-lives shorter than 1h. The total number of short-lived nuclides is 26. All the main nuclides are regularly identified and the activities have been obtained with reasonable accuracy throughout the years. The overall deviation of the results has decreased in 13 years. The effects of true coincidence summing and discrepancies in nuclear data have been identified as potential sources of remaining discrepancies. All the participants have found this type of comparison very useful.

  17. Counteracting the climate effects of volcanic eruptions using short-lived greenhouse gases

    NASA Astrophysics Data System (ADS)

    Fuglestvedt, Jan S.; Samset, Bjørn H.; Shine, Keith P.

    2014-12-01

    A large volcanic eruption might constitute a climate emergency, significantly altering global temperature and precipitation for several years. Major future eruptions will occur, but their size or timing cannot be predicted. We show, for the first time, that it may be possible to counteract these climate effects through deliberate emissions of short-lived greenhouse gases, dampening the abrupt impact of an eruption. We estimate an emission pathway countering a hypothetical eruption 3 times the size of Mount Pinatubo in 1991. We use a global climate model to evaluate global and regional responses to the eruption, with and without counteremissions. We then raise practical, financial, and ethical questions related to such a strategy. Unlike the more commonly discussed geoengineering to mitigate warming from long-lived greenhouse gases, designed emissions to counter temporary cooling would not have the disadvantage of needing to be sustained over long periods. Nevertheless, implementation would still face significant challenges.

  18. Establishing appropriate measures for monitoring aging in birds: comparing short and long lived species

    USGS Publications Warehouse

    Ottinger, M.A.; Reed, E.; Wu, J.; Thompson, N.; French, J.B.

    2003-01-01

    In order to reveal patterns of reproductive aging in birds we focus on a short lived species, the Japanese quail and the American kestrel, which has a life span of medium length. Quail have been studied extensively in the laboratory as models for understanding avian endocrinology and behavior, and as a subject for toxicological research and testing. In the lab, Japanese quail show age-related deterioration in endocrine, behavioral, and sensory system responses; the American kestrel is relatively long lived and shows moderate evidence of senescence in the oldest birds. Using data collected from captive kestrels at the Patuxent Wildlife Research Center, a database was designed to document selected parameters over the life cycle of the kestrels. Life table data collated from many species indicate that longer lived species of birds show senescence in survival ability but this pattern has not been established for reproductive function. We suggest that useful comparisons among species can be made by identifying stages in reproductive life history, organized on a relative time scale. Preliminary data from quail and kestrels, admittedly only two species, do not yet indicate a pattern of greater reproductive senescence in longer-lived birds.

  19. Health co-benefits of mitigating short-lived climate forcers

    NASA Astrophysics Data System (ADS)

    Anenberg, S.

    2011-12-01

    Tropospheric ozone and black carbon (BC), a component of fine particulate matter (PM2.5), are associated with premature mortality and disrupt global and regional climate. While attention to their impacts on climate is relatively new, these pollutants have been regulated under health-based standards in the US and elsewhere in the world for decades. Understanding the health benefits of reducing short-lived climate forcers may help inform mitigation strategies, since health will likely continue to drive concern over air quality in the future. Several recent studies have examined the health and climate co-benefits of control measures targeting BC and methane, an ozone precursor. This talk will highlight the health benefits of 14 presently available BC and methane mitigation measures examined in the United Nations Environment Programme/World Meteorological Organization Integrated Assessment of Black Carbon and Ozone. Fully implementing these specific measures is estimated to avoid 1-5 million annual ozone and PM2.5-related premature deaths globally in 2030, >80% of which occur in Asia. BC mitigation measures are estimated to achieve ~98% of the avoided deaths from all measures, due to associated reductions of non-methane ozone precursor and organic carbon emissions and stronger mortality relationships for PM2.5 relative to ozone. These substantial public health co-benefits of mitigating short-lived climate forcers are independent of whether CO2 measures are enacted. Further analyses are needed to improve economic valuation of the varied impacts of short-lived climate forcers and quantify the benefits and costs of these measures in individual countries or regions to support policy decisions made at the national level.

  20. Preparing isomerically pure beams of short-lived nuclei at JYFLTRAP

    NASA Astrophysics Data System (ADS)

    Eronen, T.; Elomaa, V.-V.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Rahaman, S.; Rissanen, J.; Weber, C.; Äystö, J.

    2008-10-01

    A new procedure to prepare isomerically clean samples of short-lived ions with a mass resolving power of more than 1 × 105 has been developed at the JYFLTRAP tandem Penning trap system. The method utilises a dipolar rf-excitation of the ion motion with separated oscillatory fields in the precision trap. During a subsequent retransfer to the purification trap, the contaminants are rejected and as a consequence, the remaining bunch is isomerically cleaned. This newly-developed method is suitable for very high-resolution cleaning and is at least a factor of five faster than the methods used so far in Penning trap mass spectrometry.

  1. Inducible transgenic expression in the short-lived fish Nothobranchius furzeri.

    PubMed

    Allard, J B; Kamei, H; Duan, C

    2013-05-01

    This study demonstrates inducible transgenic expression in the exceptionally short-lived turquoise killifish Nothobranchius furzeri, which is a useful vertebrate model for ageing research. Transgenic N. furzeri bearing a green fluorescent protein (Gfp) containing construct under the control of a heat shock protein 70 promoter were generated, heat shock-induced and reversible Gfp expression was demonstrated and germline transmission of the transgene to the F1 and F2 generations was achieved. The availability of this inducible transgenic expression system will make the study of ageing-related antagonistically pleiotropic genes possible using this unique vertebrate model organism.

  2. Tantalum-178--a short-lived nuclide for nuclear medicine: development of a potential generator system.

    PubMed

    Neirinckx, R D; Jones, A G; Davis, M A; Harris, G I; Holman, B L

    1978-05-01

    We describe a chemical separation that may form the basis of a generator system for the short-lived radionuclide Ta-178 (T 1/2 = 9 min). The parent nuclide W-178 (T 1/2 = 21.7 days) is loaded on an anion-exchange column and the daughter eluted with a mixture of dilute hydrochloric acid and hydrogen peroxide. The yields of tantalum and the breakthrough of the tungsten parent as a function of the eluting conditions are discussed, and preliminary animal distribution data are presented for various treatments of the eluant solution. PMID:641574

  3. Coupling a Knudsen reactor with the short lived radioactive tracer (13)N for atmospheric chemistry studies.

    PubMed

    Schreiber, S; Kerbrat, M; Huthwelker, T; Birrer, M; Ammann, M

    2013-03-01

    A Knudsen cell flow reactor was coupled to an online gas phase source of the short-lived radioactive tracer (13)N to study the adsorption of nitrogen oxides on ice at temperatures relevant for the upper troposphere. This novel approach has several benefits over the conventional coupling of a Knudsen cell with a mass spectrometer. Experiments at lower partial pressures close to atmospheric conditions are possible. The uptake to the substrate is a direct observable of the experiment. Operation of the experiment in continuous or pulse mode allows to retrieve steady state uptake kinetics and more details of adsorption and desorption kinetics.

  4. Mass Measurement of Short-lived Nuclei at HIRFL-CSR

    NASA Astrophysics Data System (ADS)

    Wang, M.; Xu, H. S.; Zhang, Y. H.; Tu, X. L.; Litvinov, Yu. A.

    2014-03-01

    Four campaigns of mass measurements for short-lived nuclei have been conducted using an isochronous mass spectrometry (IMS) technique at HIRFL-CSR(Cooler Storage Ring) in Lanzhou. The radioactive nuclei were produced by projectile fragmentation and injected into the experimental storage ring CSRe. Revolution times of the ions stored in the CSRe were measured from which masses of 78Kr, 58Ni, 86Kr and 112Sn fragments have been determined with a relative uncertainty of about 10-6-10-7. The experimental results are presented and their impacts on nucleosynthesis in the rp process and nuclear structure are discussed.

  5. An analysis of a short-lived outbreak of dengue fever in Mauritius.

    PubMed

    Ramchurn, S K; Moheeput, K; Goorah, S S

    2009-01-01

    During the month of June 2009, Mauritius experienced a short-lived outbreak of dengue fever localised in its capital city Port Louis. Aedes albopictus, a secondary vector of dengue viruses, was the probable vector. We introduce a method which combines Google Earth images, stochastic cellular automata and scale free network ideas to map this outbreak. The method could complement other techniques to forecast the evolution of potential localised mosquito-borne viral outbreaks in Mauritius and in at-risk locations elsewhere for public health planning purposes.

  6. Inducible transgenic expression in the short-lived fish Nothobranchius furzeri.

    PubMed

    Allard, J B; Kamei, H; Duan, C

    2013-05-01

    This study demonstrates inducible transgenic expression in the exceptionally short-lived turquoise killifish Nothobranchius furzeri, which is a useful vertebrate model for ageing research. Transgenic N. furzeri bearing a green fluorescent protein (Gfp) containing construct under the control of a heat shock protein 70 promoter were generated, heat shock-induced and reversible Gfp expression was demonstrated and germline transmission of the transgene to the F1 and F2 generations was achieved. The availability of this inducible transgenic expression system will make the study of ageing-related antagonistically pleiotropic genes possible using this unique vertebrate model organism. PMID:23639168

  7. An effective technique for the storage of short lived radioactive gaseous waste.

    PubMed

    Schweiger, Lutz

    2011-09-01

    An effective technique is described to deal with volatile, short lived radioactive waste generated as a result of the routinely produced positron emission tomography (PET) radiopharmaceutical 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG). All radioactive gases and aerosols created during the synthesis are collected and stored safely in commercially available TEDLAR gas sampling bags. Once these collected PET by-products decay, the TEDLAR gas bags can be easily emptied and reused. This improved technique is effective, safe, reliable and economical. PMID:21592805

  8. Short-lived orogenic cycles and the eclogitization of cold crust by spasmodic hot fluids.

    PubMed

    Camacho, Alfredo; Lee, James K W; Hensen, Bastiaan J; Braun, Jean

    2005-06-30

    Collision tectonics and the associated transformation of continental crust to high-pressure rocks (eclogites) are generally well-understood processes, but important contradictions remain between tectonothermal models and petrological-isotopic data obtained from such rocks. Here we use 40Ar-39Ar data coupled with a thermal model to constrain the time-integrated duration of an orogenic cycle (the burial and exhumation of a particular segment of the crust) to be less than 13 Myr. We also determine the total duration of associated metamorphic events to be approximately 20 kyr, and of individual heat pulses experienced by the rocks to be as short as 10 years. Such short timescales are indicative of rapid tectonic processes associated with catastrophic deformation events (earthquakes). Such events triggered transient heat advection by hot fluid along deformation (shear) zones, which cut relatively cool and dry subducted crust. In contrast to current thermal models that assume thermal equilibrium and invoke high ambient temperatures in the thickened crust, our non-steady-state cold-crust model satisfactorily explains several otherwise contradictory geological observations.

  9. Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies

    SciTech Connect

    Menon, Surabi; Quinn, P.K.; Bates, T.S.; Baum, E.; Doubleday, N.; Fiore, A.M.; Flanner, M.; Fridlind, A.; Garrett, T.J.; Koch, D.; Menon, S.; Shindell, D.; Stohl, A.; Warren, S.G.

    2007-09-24

    Several short-lived pollutants known to impact Arctic climate may be contributing to the accelerated rates of warming observed in this region relative to the global annually averaged temperature increase. Here, we present a summary of the short-lived pollutants that impact Arctic climate including methane, tropospheric ozone, and tropospheric aerosols. For each pollutant, we provide a description of the major sources and the mechanism of forcing. We also provide the first seasonally averaged forcing and corresponding temperature response estimates focused specifically on the Arctic. The calculations indicate that the forcings due to black carbon, methane, and tropospheric ozone lead to a positive surface temperature response indicating the need to reduce emissions of these species within and outside the Arctic. Additional aerosol species may also lead to surface warming if the aerosol is coincident with thin, low lying clouds. We suggest strategies for reducing the warming based on current knowledge and discuss directions for future research to address the large remaining uncertainties.

  10. Short and long term chemical and isotopic variations of Lake Trasimeno (Italy)

    NASA Astrophysics Data System (ADS)

    Frondini, Francesco; Dragoni, Walter; Chiodini, Giovanni; Caliro, Stefano; Cardellini, Carlo; Donnini, Marco; Morgantini, Nicola

    2016-04-01

    Lake Trasimeno, located in Umbria (central Italy), is a shallow lake of a remarkable naturalistic interest and a significant resource for the economy of the region (Ludovisi and Gaino, 2010; Dragoni, 2004). The Lake Trasimeno has an average area of about 124 km2 with a maximum depth of approximately 5.5 m, has no natural outlet and the volume of water stored is strictly linked to rainfall. In order to limit water level variations in 1898 an efficient outlet was built. At present the water exits from the Lake only when the level reaches a fixed threshold above the outlet channel, so during periods with low precipitation the evaporation becomes the most relevant output from the lake. For instance, between 1989 and 2013 the outlet did not work, and the maximum depth of the lake was reduced to little more than three meters. In the framework of climate change, it is important to understand the changes that could affect Lake Trasimeno in the near future. To this aim it is necessary to individuate the long term trends of the hydrologic, chemical and physical characteristics of the Trasimeno water and distinguish them from the short term variations. At the present it is available a long record of hydrologic data allowing reliable studies on quantitative variations at Lake Trasimeno (Dragoni et al., 2015; Dragoni et al., 2012; Ludovisi and Gaino, 2010), but the definition of the chemical and isotopic trends of lake water it is still a problematic task. On the basis of new chemical and isotopic data, collected from 2006 to 2015, it is possible to observe (i) short term and/or very short (seasonal) variations in temperature, salinity and saturation state with respect to carbonate minerals and a long term trends in isotopic composition of water and total load of mobile species (Cl, Na). The short term variations readily respond to the precipitation regime and are strongly related to lake level; the long term trend is probably related to the progressive increase of near

  11. Short and long term chemical and isotopic variations of Lake Trasimeno (Italy)

    NASA Astrophysics Data System (ADS)

    Frondini, Francesco; Dragoni, Walter; Chiodini, Giovanni; Caliro, Stefano; Cardellini, Carlo; Donnini, Marco; Morgantini, Nicola

    2016-04-01

    Lake Trasimeno, located in Umbria (central Italy), is a shallow lake of a remarkable naturalistic interest and a significant resource for the economy of the region (Ludovisi and Gaino, 2010; Dragoni, 2004). The Lake Trasimeno has an average area of about 124 km2 with a maximum depth of approximately 5.5 m, has no natural outlet and the volume of water stored is strictly linked to rainfall. In order to limit water level variations in 1898 an efficient outlet was built. At present the water exits from the Lake only when the level reaches a fixed threshold above the outlet channel, so during periods with low precipitation the evaporation becomes the most relevant output from the lake. For instance, between 1989 and 2013 the outlet did not work, and the maximum depth of the lake was reduced to little more than three meters. In the framework of climate change, it is important to understand the changes that could affect Lake Trasimeno in the near future. To this aim it is necessary to individuate the long term trends of the hydrologic, chemical and physical characteristics of the Trasimeno water and distinguish them from the short term variations. At the present it is available a long record of hydrologic data allowing reliable studies on quantitative variations at Lake Trasimeno (Dragoni et al., 2015; Dragoni et al., 2012; Ludovisi and Gaino, 2010), but the definition of the chemical and isotopic trends of lake water it is still a problematic task. On the basis of new chemical and isotopic data, collected from 2006 to 2015, it is possible to observe (i) short term and/or very short (seasonal) variations in temperature, salinity and saturation state with respect to carbonate minerals and a long term trends in isotopic composition of water and total load of mobile species (Cl, Na). The short term variations readily respond to the precipitation regime and are strongly related to lake level; the long term trend is probably related to the progressive increase of near

  12. Did Solar Energetic Particles Produce the Short-lived Nuclides Present in the Early Solar System?

    NASA Astrophysics Data System (ADS)

    Goswami, J. N.; Marhas, K. K.; Sahijpal, S.

    2001-03-01

    Production of the short-lived nuclides 41Ca, 36Cl, 26Al, and 53Mn by solar energetic particles (SEP) interacting with dust grains of chondritic (=solar) composition is estimated considering a broad range of spectral parameters for the SEP and appropriate nuclear reaction cross sections. The dust grains are assumed to follow a power-law size distribution and to range in size from 10 μm to 1 cm. The possibility that an enhanced flux of SEP from an active early (T Tauri) Sun could have been responsible for the production of these short-lived nuclides in the early solar system is investigated. SEP production of 41Ca and 36Cl will match their abundances in the early solar system inferred from meteorite data if the SEP irradiation duration was ~5×105-106 yr and the SEP flux was higher by a factor of more than 5×103 than the contemporary long-term averaged value of Nproton (E>10 MeV)~100 cm-2 s-1. However, corresponding production of 26Al will be much below the level needed to match its inferred abundance in the early solar system. SEP production, therefore, fails to explain the observed correlated presence of 41Ca and 26Al with canonical initial abundances in early solar system solids. The abundance of 53Mn in the early solar system is not tightly constrained by the meteorite data, and the various estimates differ by a factor of 5. Coproduction of 41Ca, 36Cl, and 53Mn that will match the meteorite data for the higher initial abundance of 53Mn is possible if the SEP irradiation persisted for about a million years or more with a flux enhancement factor of ~5000-10,000. On the other hand, the lower initial value of 53Mn can also be matched by a flux enhancement factor of ~1000 and an irradiation duration of a few million years; the corresponding production of the other nuclides will be <=10% of the level needed to match their abundances in the early solar system. Target abundance consideration rules out the possibility of SEP production of 60Fe, another short-lived

  13. Seeds of alpine plants are short lived: implications for long-term conservation

    PubMed Central

    Mondoni, Andrea; Probert, Robin J.; Rossi, Graziano; Vegini, Emanuele; Hay, Fiona R.

    2011-01-01

    Background and Aims Alpine plants are considered one of the groups of species most sensitive to the direct and indirect threats to ecosystems caused by land use and climate change. Collecting and banking seeds of plant species is recognized as an effective tool for providing propagating material to re-establish wild plant populations and for habitat repair. However, seeds from cold wet environments have been shown to be relatively short lived in storage, and therefore successful long-term seed conservation for alpine plants may be difficult. Here, the life spans of 69 seed lots representing 63 related species from alpine and lowland locations from northern Italy are compared. Methods Seeds were placed into experimental storage at 45 °C and 60 % relative humidity (RH) and regularly sampled for germination. The time taken in storage for viability to fall to 50 % (p50) was determined using probit analysis and used as a measure of relative seed longevity between seed lots. Key Results Across species, p50 at 45 °C and 60 % RH varied from 4·7 to 95·5 d. Seed lots from alpine populations/species had significantly lower p50 values compared with those from lowland populations/species; the lowland seed lots showed a slower rate of loss of germinability, higher initial seed viability, or both. Seeds were progressively longer lived with increased temperature and decreased rainfall at the collecting site. Conclusions Seeds of alpine plants are short lived in storage compared with those from lowland populations/related taxa. The lower resistance to ageing in seeds of alpine plants may arise from low selection pressure for seed resistance to ageing and/or damage incurred during seed development due to the cool wet conditions of the alpine climate. Long-term seed conservation of several alpine species using conventional seed banking methods will be problematic. PMID:21081585

  14. The Irradiation Origin of Beryllium Radioisotopes and Other Short-lived Radionuclides

    NASA Astrophysics Data System (ADS)

    Gounelle, Matthieu; Shu, Frank H.; Shang, Hsien; Glassgold, A. E.; Rehm, K. E.; Lee, Typhoon

    2006-04-01

    Two explanations exist for the short-lived radionuclides (T1/2<=5 Myr) present in the solar system when the calcium-aluminum-rich inclusions (CAIs) first formed. They originated either from the ejecta of a supernova or by the in situ irradiation of nebular dust by energetic particles. With a half-life of only 53 days, 7Be is then the key discriminant, since it can be made only by irradiation. Using the same irradiation model developed earlier by our group, we calculate the yield of 7Be. Within model uncertainties associated mainly with nuclear cross sections, we obtain agreement with the experimental value. Moreover, if 7Be and 10Be have the same origin, the irradiation time must be short (a few to tens of years), and the proton flux must be of order F~2×1010 cm-2 s-1. The X-wind model provides a natural astrophysical setting that gives the requisite conditions. In the same irradiation environment, 26Al, 36Cl, and 53Mn are also generated at the measured levels within model uncertainties, provided that irradiation occurs under conditions reminiscent of solar impulsive events (steep energy spectra and high 3He abundance). The decoupling of the 26Al and 10Be observed in some rare CAIs receives a quantitative explanation when rare gradual events (shallow energy spectra and low 3He abundance) are considered. The yields of 41Ca are compatible with an initial solar system value inferred from the measured initial 41Ca/40Ca ratio and an estimate of the thermal metamorphism time (from Young et al.), alleviating the need for two-layer proto-CAIs. Finally, we show that the presence of supernova-produced 60Fe in the solar accretion disk does not necessarily mean that other short-lived radionuclides have a stellar origin.

  15. Disentangling the effects of CO2 and short-lived climate forcer mitigation.

    PubMed

    Rogelj, Joeri; Schaeffer, Michiel; Meinshausen, Malte; Shindell, Drew T; Hare, William; Klimont, Zbigniew; Velders, Guus J M; Amann, Markus; Schellnhuber, Hans Joachim

    2014-11-18

    Anthropogenic global warming is driven by emissions of a wide variety of radiative forcers ranging from very short-lived climate forcers (SLCFs), like black carbon, to very long-lived, like CO2. These species are often released from common sources and are therefore intricately linked. However, for reasons of simplification, this CO2-SLCF linkage was often disregarded in long-term projections of earlier studies. Here we explicitly account for CO2-SLCF linkages and show that the short- and long-term climate effects of many SLCF measures consistently become smaller in scenarios that keep warming to below 2 °C relative to preindustrial levels. Although long-term mitigation of methane and hydrofluorocarbons are integral parts of 2 °C scenarios, early action on these species mainly influences near-term temperatures and brings small benefits for limiting maximum warming relative to comparable reductions taking place later. Furthermore, we find that maximum 21st-century warming in 2 °C-consistent scenarios is largely unaffected by additional black-carbon-related measures because key emission sources are already phased-out through CO2 mitigation. Our study demonstrates the importance of coherently considering CO2-SLCF coevolutions. Failing to do so leads to strongly and consistently overestimating the effect of SLCF measures in climate stabilization scenarios. Our results reinforce that SLCF measures are to be considered complementary rather than a substitute for early and stringent CO2 mitigation. Near-term SLCF measures do not allow for more time for CO2 mitigation. We disentangle and resolve the distinct benefits across different species and therewith facilitate an integrated strategy for mitigating both short and long-term climate change. PMID:25368182

  16. Muscle senescence in short-lived wild mammals, the soricine shrews Blarina brevicauda and Sorex palustris.

    PubMed

    Hindle, Allyson G; Lawler, John M; Campbell, Kevin L; Horning, Markus

    2009-06-01

    Red-toothed (soricine) shrews are consummate predators exhibiting the highest energy turnovers and shortest life spans (ca. 18 months) of any mammal, yet virtually nothing is known regarding their physiological aging. We assessed the emerging pattern of skeletal muscle senescence (contractile/connective tissue components) in sympatric species, the semi-aquatic water shrew (WS), Sorex palustris, and the terrestrial short-tailed shrew (STS), Blarina brevicauda, to determine if muscle aging occurs in wild, short-lived mammals (H(0): shrews do not survive to an age where senescence occurs), and if so, whether these alterations are species-specific. Gracilis muscles were collected from first-year (n=17) and second-year (n=17) field-caught shrews. Consistent with typical mammalian aging, collagen content (% area) increased with age in both species (S. palustris: approximately 50%; B. brevicauda: approximately 60%). Muscle was dominated by stiffer Type I collagen, and the ratio of collagen Type I:Type III more than doubled with age. The area ratio of muscle:collagen decreased with age in both species, but was considerably lower in adult STS, suggesting species-specificity of senescence. Extracellular space was age-elevated in B. brevicauda, but was preserved in S. palustris ( approximately 50 vs. 10% elevation). Though juvenile interspecific comparisons revealed no significance, adult WS myocytes had 68% larger cross-sectional area and occurred at 28% lower fibers/area than those of adult STS. We demonstrate that age-related muscle senescence does occur in wild-caught, short-lived mammals, and we therefore reject this classic aging theory tenet. Our findings moreover illustrate that differential age adjustments in contractile/connective tissue components of muscle occur in the two species of wild-caught shrews. PMID:19296507

  17. Disentangling the effects of CO2 and short-lived climate forcer mitigation.

    PubMed

    Rogelj, Joeri; Schaeffer, Michiel; Meinshausen, Malte; Shindell, Drew T; Hare, William; Klimont, Zbigniew; Velders, Guus J M; Amann, Markus; Schellnhuber, Hans Joachim

    2014-11-18

    Anthropogenic global warming is driven by emissions of a wide variety of radiative forcers ranging from very short-lived climate forcers (SLCFs), like black carbon, to very long-lived, like CO2. These species are often released from common sources and are therefore intricately linked. However, for reasons of simplification, this CO2-SLCF linkage was often disregarded in long-term projections of earlier studies. Here we explicitly account for CO2-SLCF linkages and show that the short- and long-term climate effects of many SLCF measures consistently become smaller in scenarios that keep warming to below 2 °C relative to preindustrial levels. Although long-term mitigation of methane and hydrofluorocarbons are integral parts of 2 °C scenarios, early action on these species mainly influences near-term temperatures and brings small benefits for limiting maximum warming relative to comparable reductions taking place later. Furthermore, we find that maximum 21st-century warming in 2 °C-consistent scenarios is largely unaffected by additional black-carbon-related measures because key emission sources are already phased-out through CO2 mitigation. Our study demonstrates the importance of coherently considering CO2-SLCF coevolutions. Failing to do so leads to strongly and consistently overestimating the effect of SLCF measures in climate stabilization scenarios. Our results reinforce that SLCF measures are to be considered complementary rather than a substitute for early and stringent CO2 mitigation. Near-term SLCF measures do not allow for more time for CO2 mitigation. We disentangle and resolve the distinct benefits across different species and therewith facilitate an integrated strategy for mitigating both short and long-term climate change.

  18. Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-lived Radioisotopes with a Shock Wave. III. Rotating Three-dimensional Cloud Cores

    NASA Astrophysics Data System (ADS)

    Boss, Alan P.; Keiser, Sandra A.

    2014-06-01

    A key test of the supernova triggering and injection hypothesis for the origin of the solar system's short-lived radioisotopes is to reproduce the inferred initial abundances of these isotopes. We present here the most detailed models to date of the shock wave triggering and injection process, where shock waves with varied properties strike fully three-dimensional, rotating, dense cloud cores. The models are calculated with the FLASH adaptive mesh hydrodynamics code. Three different outcomes can result: triggered collapse leading to fragmentation into a multiple protostar system; triggered collapse leading to a single protostar embedded in a protostellar disk; or failure to undergo dynamic collapse. Shock wave material is injected into the collapsing clouds through Rayleigh-Taylor fingers, resulting in initially inhomogeneous distributions in the protostars and protostellar disks. Cloud rotation about an axis aligned with the shock propagation direction does not increase the injection efficiency appreciably, as the shock parameters were chosen to be optimal for injection even in the absence of rotation. For a shock wave from a core-collapse supernova, the dilution factors for supernova material are in the range of ~10-4 to ~3 × 10-4, in agreement with recent laboratory estimates of the required amount of dilution for 60Fe and 26Al. We conclude that a type II supernova remains as a promising candidate for synthesizing the solar system's short-lived radioisotopes shortly before their injection into the presolar cloud core by the supernova's remnant shock wave.

  19. Radio Constraints on Long-lived Magnetar Remnants in Short Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Fong, W.; Metzger, B. D.; Berger, E.; Özel, F.

    2016-11-01

    The merger of a neutron star (NS) binary may result in the formation of a rapidly spinning magnetar. The magnetar can potentially survive for seconds or longer as a supramassive NS before collapsing to a black hole if, indeed, it collapses at all. During this process, a fraction of the magnetar’s rotational energy of ∼1053 erg is transferred via magnetic spin-down to the surrounding ejecta. The resulting interaction between the ejecta and the surrounding circumburst medium powers a year-long or greater synchrotron radio transient. We present a search for radio emission with the Very Large Array following nine short-duration gamma-ray bursts (GRBs) at rest-frame times of ≈1.3–7.6 yr after the bursts, focusing on those events that exhibit early-time excess X-ray emission that may signify the presence of magnetars. We place upper limits of ≲18–32 μJy on the 6.0 GHz radio emission, corresponding to spectral luminosities of ≲(0.05–8.3) × 1039 erg s‑1. Comparing these limits to the predicted radio emission from a long-lived remnant and incorporating measurements of the circumburst densities from broadband modeling of short GRB afterglows, we rule out a stable magnetar with an energy of 1053 erg for half of the events in our sample. A supramassive remnant that injects a lower rotational energy of 1052 erg is ruled out for a single event, GRB 050724A. This study represents the deepest and most extensive search for long-term radio emission following short GRBs to date, and thus the most stringent limits placed on the physical properties of magnetars associated with short GRBs from radio observations.

  20. Long- and short-lived nuclide constraints on the recent evolution of permafrost soils

    NASA Astrophysics Data System (ADS)

    Bagard, M.; Chabaux, F. J.; Rihs, S.; Pokrovsky, O. S.; Prokushkin, A. S.; Viers, J.

    2011-12-01

    Frozen permafrost ecosystems are particularly sensitive to climate warming, which notably induces a deepening of the active layer (the maximum thawing depth during summer time). As a consequence, geochemical and hydrological fluxes within boreal areas are expected to be significantly affected in the future. Understanding the relationship between environmental changes and permafrost modifications is then a major challenge. This work aims to evaluate in a Siberian watershed the dynamics of the permafrost active layer and their recent modifications by combining a classic study of long-lived nuclides to the study of short-lived nuclides of U and Th decay series. Two soil profiles, located on opposite slopes (north- and south-facing slopes) of the Kulingdakan watershed (Putorana Plateau, Central Siberia), were sampled at several depths within the active layer and (238U), (234U), (232Th), (230Th), (226Ra), (228Ra), (228Th) and (210Pb) were measured on bulk soil samples by TIMS or gamma spectrometry. Our results show that south-facing and north-facing soil profiles are significantly different in terms of evolution of chemical concentrations and nuclide activities; north-facing soil profile is strongly affected by atmospheric inputs whereas long-lived nuclide dynamics within south-facing soil profile are dominated by weathering and exhibit more complex patterns. The amount of above-ground biomass being the single varying parameter between the two slopes of the watershed, we suggest that the structuring of permafrost active layer is very sensitive to vegetation activity and that the functioning of boreal soils will be significantly modified by its development due to more favorable climatic conditions. Moreover, the coupling of long and short-lived nuclides highlights the superimposition of a recent mobilization of chemical elements within soils (<10 years) over a much older soil structure (>8000 years), which can be observed for both soil profiles. The shallowest layer of

  1. ASTROPHYSICAL SHRAPNEL: DISCRIMINATING AMONG NEAR-EARTH STELLAR EXPLOSION SOURCES OF LIVE RADIOACTIVE ISOTOPES

    SciTech Connect

    Fry, Brian J.; Fields, Brian D.; Ellis, John R.

    2015-02-10

    We consider the production and deposition on Earth of isotopes with half-lives in the range 10{sup 5}-10{sup 8} yr that might provide signatures of nearby stellar explosions, extending previous analyses of Core-Collapse Supernovae (CCSNe) to include Electron-Capture Supernovae (ECSNe), Super-Asymptotic Giant Branch (SAGB) stars, Thermonuclear/Type Ia Supernovae (TNSNe), and Kilonovae/Neutron Star Mergers (KNe). We revisit previous estimates of the {sup 60}Fe and {sup 26}Al signatures, and extend these estimates to include {sup 244}Pu and {sup 53}Mn. We discuss interpretations of the {sup 60}Fe signals in terrestrial and lunar reservoirs in terms of a nearby stellar ejection ∼2.2 Myr ago, showing that (1) the {sup 60}Fe yield rules out the TNSN and KN interpretations, (2) the {sup 60}Fe signals highly constrain SAGB interpretations but do not completely them rule out, (3) are consistent with a CCSN origin, and (4) are highly compatible with an ECSN interpretation. Future measurements could resolve the radioisotope deposition over time, and we use the Sedov blast wave solution to illustrate possible time-resolved profiles. Measuring such profiles would independently probe the blast properties including distance, and would provide additional constraints for the nature of the explosion.

  2. The short-lived African turquoise killifish: an emerging experimental model for ageing.

    PubMed

    Kim, Yumi; Nam, Hong Gil; Valenzano, Dario Riccardo

    2016-02-01

    Human ageing is a fundamental biological process that leads to functional decay, increased risk for various diseases and, ultimately, death. Some of the basic biological mechanisms underlying human ageing are shared with other organisms; thus, animal models have been invaluable in providing key mechanistic and molecular insights into the common bases of biological ageing. In this Review, we briefly summarise the major applications of the most commonly used model organisms adopted in ageing research and highlight their relevance in understanding human ageing. We compare the strengths and limitations of different model organisms and discuss in detail an emerging ageing model, the short-lived African turquoise killifish. We review the recent progress made in using the turquoise killifish to study the biology of ageing and discuss potential future applications of this promising animal model. PMID:26839399

  3. New Developments for Isochronous Mass Measurements of Short-Lived Nuclei

    SciTech Connect

    Knoebel, R.; Litvinov, S. A.; Boutin, D.; Chen, L.; Geissel, H.; Litvinov, Yu. A.; Scheidenberger, C.; Winckler, N.; Sun, B.; Beckert, K.; Beller, P.; Bosch, F.; Brandau, C.; Dimopoulou, C.; Dolinskii, A.; Kozhuharov, C.; Mazzocco, M.; Montes, F.; Muenzenberg, G.; Nociforo, C.

    2007-02-26

    The combination of the in-flight separator FRS and the storage-ring ESR at GSI offers unique possibilities for high accuracy mass and lifetime measurements of bare and few-electron fragments. Operating the ESR in the isochronous mode allows for measurements of revolution frequencies of stored ions without cooling. Isochronous Mass Spectrometry (IMS) can be applied to fragments with half-lives as short as several tens of microseconds. Newly developed magnetic rigidity tagging increases the resolving power of IMS to about 500000. IMS can be used to measure masses of nuclei with rates even lower than one ion per day, a property also needed for the purpose of the ILIMA project at the future facility FAIR.

  4. The short-lived African turquoise killifish: an emerging experimental model for ageing

    PubMed Central

    Kim, Yumi; Nam, Hong Gil; Valenzano, Dario Riccardo

    2016-01-01

    ABSTRACT Human ageing is a fundamental biological process that leads to functional decay, increased risk for various diseases and, ultimately, death. Some of the basic biological mechanisms underlying human ageing are shared with other organisms; thus, animal models have been invaluable in providing key mechanistic and molecular insights into the common bases of biological ageing. In this Review, we briefly summarise the major applications of the most commonly used model organisms adopted in ageing research and highlight their relevance in understanding human ageing. We compare the strengths and limitations of different model organisms and discuss in detail an emerging ageing model, the short-lived African turquoise killifish. We review the recent progress made in using the turquoise killifish to study the biology of ageing and discuss potential future applications of this promising animal model. PMID:26839399

  5. The short-lived African turquoise killifish: an emerging experimental model for ageing.

    PubMed

    Kim, Yumi; Nam, Hong Gil; Valenzano, Dario Riccardo

    2016-02-01

    Human ageing is a fundamental biological process that leads to functional decay, increased risk for various diseases and, ultimately, death. Some of the basic biological mechanisms underlying human ageing are shared with other organisms; thus, animal models have been invaluable in providing key mechanistic and molecular insights into the common bases of biological ageing. In this Review, we briefly summarise the major applications of the most commonly used model organisms adopted in ageing research and highlight their relevance in understanding human ageing. We compare the strengths and limitations of different model organisms and discuss in detail an emerging ageing model, the short-lived African turquoise killifish. We review the recent progress made in using the turquoise killifish to study the biology of ageing and discuss potential future applications of this promising animal model.

  6. The origin and disappearance of the late Pleistocene-early Holocene short-lived coastal wetlands along the Carmel coast, Israel

    NASA Astrophysics Data System (ADS)

    Sivan, Dorit; Greenbaum, Noam; Cohen-Seffer, Ronit; Sisma-Ventura, Guy; Almogi-Labin, Ahuva

    The formation of short-lived backswamps along the Carmel coast of Israel coincides with the rapid global sea-level rise during the late Pleistocene-early Holocene transition. The current study shows that the wetland phenomena originated around 10,000 yr ago and dried up shortly before the local Pre-Pottery Neolithic humans settled on the wetland dark clay sediments 9430 cal yr BP. Palaeontological and stable-isotope data were used in this study to elucidate previously published sedimentological reconstruction obtained from a core drilled into the western trough of the Carmel coastal plain. The water body contained typical brackish calcareous fauna, with variable numerical abundance and low species richness of ostracods and foraminifera. The δ 18O and δ 13C of the ostracod Cyprideis torosa show close similarity to the present Pleistocene coastal aquifer isotopic values. This study therefore concludes that the wetlands were shallow-water bodies fed by groundwater, with no evidence of sea-water mixing. It seems that they developed as the result of high groundwater levels, transportation of sediments landward, and deposition of sand bars at the paleo-river mouths. It is still not fully understood why these wetlands deteriorated abruptly and disappeared within less than 1000 yr.

  7. CARIBIC observations of short-lived halocarbons and carbonyl sulphide over Asia

    NASA Astrophysics Data System (ADS)

    Leedham, E.; Wisher, A.; Oram, D.; Baker, A. K.; Brenninkmeijer, C. A.

    2013-12-01

    The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container, www.caribic-atmospheric.com) aims to investigate the spatial and temporal distribution of a wide-range of compounds, including those of marine origin/influence, via ~monthly flights to collect in situ data and whole air samples aboard a commercial Lufthansa aircraft. CARIBIC measures up to an altitude of 12 km, allowing the influence of marine compounds on the upper troposphere/lower stratosphere (UTLS) to be explored. In particular, CARIBIC is a useful tool for exploring the impact of very short lived halocarbons (e.g. CH2Br2, CHBr3), whose impact on stratospheric ozone is dependent on convective uplift to the UTLS, a process which is not yet fully quantified. As part of the suite of CARIBIC measurements, whole air samples are analysed at the University of East Anglia (UEA) via gas chromatography mass spectrometry for carbonyl sulphide (OCS) and up to 40 halocarbons (accounting for virtually 100% of organic chlorine, bromine and iodine in the UTLS). Here we present an overview of short-lived halocarbons and OCS measured by CARIBIC. We focus on two regions of particular interest. (1) measurements made in 2012 over the tropical west Pacific to link with UEA measurements made during the SHIVA campaign. (2) measurements made during a collection of flights over India in 2008. Flights over India investigated the impact of monsoon circulation on the distribution of these compounds; for example, elevated concentrations of OCS were seen in CARIBIC samples taken over India during the summer monsoon (July - September). These flights, along with a wider range of flights over Asia (from Frankfurt to Guangzhou, Manila, Bangkok and Kuala Lumpur) can provide unique information on the influence of tropical convection and monsoon circulation on halocarbon and OCS transport within this region.

  8. Seasonal Short-Lived Radium Activity in the Venice Lagoon: The Role of Residence Time

    NASA Astrophysics Data System (ADS)

    Rapaglia, J.; Ferrarin, C.; Zaggia, L.; Umgiesser, G.; Zuppi, G.; Manfe', G.

    2008-12-01

    Radium is considered to be an excellent tracer of submarine groundwater discharge (SGD) and, therefore, has been used in many studies of this process in the past decade. Comprehensive surveys of excess 223,224Ra activity were completed in the surface waters of the Venice Lagoon over 6 seasons in order to quantify seasonal variation of SGD into the lagoon. The mass balance of radium found that SGD was 5-26 times greater than total river discharge (35.5 m3 s-1), and that total SGD could differ by almost an order of magnitude pending season. Several possible parameters, which may cause the seasonal variation, were tested. These included precipitation events, average tidal elevation, average tidal excursion, wind speed and direction, yet none provided a satisfactory explanation for the difference. Residence time based on a hydrodynamic model, however, was very strongly correlated with the observed variation. When the average residence time in the lagoon was low (5 days) the SGD was calculated to be 930 m3 s-1 and when the average residence time was high (9 days) the SGD was quantified as 160 m3 s-1. Radioactive decay is already accounted for in the mass balance model and therefore this correlation must be explained by another process. The Venice Lagoon is characterized by low residence time during periods of spring tides and bora or northerly winds, both of which create exceptionally strong currents in the Venice Lagoon. The currents as well as the large tidal excursion which occurs at spring tides drive a recirculation of seawater through the surface sediments, which greatly increases short-lived Ra activity in the surface waters. This evidence suggests, therefore, that short-lived Ra mass balance studies, which are based on a single survey, may under or overestimate the mean annual SGD pending the hydrodynamics of the investigated location.

  9. Global Air Quality and Climate Impacts of Mitigating Short-lived Climate Pollution in China

    NASA Astrophysics Data System (ADS)

    Harper, K.; Unger, N.; Heyes, C.; Kiesewetter, G.; Klimont, Z.; Schoepp, W.; Wagner, F.

    2014-12-01

    China is a major emitter of harmful air pollutants, including the short-lived climate pollutants (SLCPs) and their precursors. Implementation of pollution control technologies provides a mechanism for simultaneously protecting human and ecosystem health and achieving near-term climate co-benefits; however, predicting the outcomes of technical and policy interventions is challenging because the SLCPs participate in both climate warming and cooling and share many common emission sources. Here, we present the results of a combined regional integrated assessment and global climate modeling study aimed at quantifying the near-term climate and air quality co-benefits of selective control of Chinese air pollution emissions. Results from IIASA's Greenhouse Gas - Air Pollution Interactions and Synergies (GAINS) integrated assessment model indicate that methane emission reductions make up > 75% of possible CO2-equivalent emission reductions of the SLCPs and their precursors in China in 2030. A multi-pollutant emission reduction scenario incorporating the 2030 Chinese pollution control measures with the highest potential for future climate impact is applied to the NASA ModelE2 - Yale Interactive Terrestrial Biosphere (NASA ModelE2-YIBs) global carbon - chemistry - climate model to assess the regional and long-range impacts of Chinese SLCP mitigation measures. Using model simulations that incorporate dynamic methane emissions and photosynthesis-dependent isoprene emissions, we quantify the impacts of Chinese reductions of the short-lived air pollutants on radiative forcing and on surface ozone and particulate air pollution. Present-day modeled methane mole fractions are evaluated against SCIAMACHY methane columns and NOAA ESRL/GMD surface flask measurements.

  10. The Effects of Stratospheric Chemistry and Transport on the Isotopic Compositions of Long-Lived Gases Measured at Earth's Surface

    NASA Astrophysics Data System (ADS)

    Kanu, A. M.; Boering, K. A.

    2014-12-01

    The isotopic compositions of a number of long-lived gases in Earth's atmosphere, including those for carbon dioxide (δ18O, Δ17O, and Δ14C), nitrous oxide (δ15N, δ15Nα, and δ18O), methane (δ13C and δD), and molecular hydrogen (δD) undergo large changes in the stratosphere. These changes arise from the often unique photochemical isotope fractionation occurring there as well as the long residence times and mean ages of stratospheric air with respect to exchange with the troposphere of up to 5 years. Stratospheric air then returns to the troposphere and, in each case, can affect the isotopic composition of these gases measured at Earth's surface. In this work, we estimate the effect of stratospheric isotope fractionation on free tropospheric isotope compositions of CO2, N2O, CH4, and H2 on an annual and global mean basis. To do so, we calculate net isotope fluxes between the stratosphere and troposphere empirically from the correlation of the measured isotope compositions of these species with measured N2O mixing ratios on whole air samples collected in the stratosphere from stratospheric aircraft and balloons coupled with independent information on the global, annually-averaged loss rate of N2O. In each case, the effect is large enough to include in global models. In addition, we present arguments and evidence that deconvolving the stratospheric influence on surface measurements from source (or other) signals on higher spatial and temporal scales than 'global' and 'annually-averaged' is also necessary when using surface measurements of isotopic compositions to constrain the magnitudes and geographic distributions of the sources of these gases to the atmosphere.

  11. Short-Lived Cages Restrict Protein Diffusion in the Plasma Membrane

    PubMed Central

    Goiko, Maria; de Bruyn, John R.; Heit, Bryan

    2016-01-01

    The plasma membrane is a heterogeneous environment characterized by anomalous diffusion and the presence of microdomains that are molecularly distinct from the bulk membrane. Using single particle tracking of the C-type lectin CD93, we have identified for the first time the transient trapping of transmembrane proteins in cage-like microdomains which restrict protein diffusion. These cages are stabilized by actin-dependent confinement regions, but are separate structures with sizes and lifespans uncorrelated to those of the underlying actin corral. These membrane cages require cholesterol for their strength and stability, with cholesterol depletion decreasing both. Despite this, cages are much larger in size and are longer lived than lipid rafts, suggesting instead that cholesterol-dependent effects on membrane fluidity or molecular packing play a role in cage formation. This diffusional compartment in the plasma membrane has characteristics of both a diffusional barrier and a membrane microdomain, with a size and lifespan intermediate between short-lived microdomains such as lipid rafts and long-lasting diffusional barriers created by the actin cytoskeleton. PMID:27725698

  12. Harvard-MIT research program in short-lived radiopharmaceuticals. Final report

    SciTech Connect

    Adelstein, S.J.

    1995-02-01

    The Harvard-MIT Research Program in Short-lived Radiopharmaceuticals was established in 1977 to foster interaction among groups working in radiopharmaceutical chemistry at Harvard Medical School, the Massachusetts Institute of Technology, and the Massachusetts General Hospital. To this was added a group at The Childrens Hospital. From these collaborations and building upon the special strengths of the participating individuals, laboratories and institutions, it was hoped that original approaches would be found for the design of new, clinically useful, radiolabeled compounds. The original thrust of this proposal included: (a) examination of the coordination chemistry of technetium as a basis for rational radiopharmaceutical design, (b) development of an ultrashort-lived radionuclide generator for the diagnosis of congenital heart disease in newborns, (c) synthesis of receptor-site-directed halopharmaceuticals, (d) improved facile labeling of complex molecules with positron-emitting radionuclides. The authors` 1986 proposal was oriented toward organs and disease, emphasizing radiolabeled agents that delineate specific functions and the distribution of receptors in brain, heart, and tumors. In 1989, they further refined their purposes and focused on two major aims: (a) synthesis and utilization of neutral technetium and rhenium complexes of high specific activity, and (b) development of new approaches to the radiolabeling of proteins, peptides, immunoglobulins, and their fragments. In 1992, the authors amended this proposal to concentrate their efforts on biologically active peptides and proteins for targeted radiodiagnosis and therapy.

  13. Transfer time and source tracing in the soil - water- -plant system deciphered by the U-and Th-series short-lived nuclides

    NASA Astrophysics Data System (ADS)

    Rihs, S.; Pierret, M.; Chabaux, F.

    2011-12-01

    Because soils form at the critical interface between the lithosphere and the atmosphere, characterization of the dynamics occurring through this compartment represents an important goal for several scientific fields and/or human activities. However, this issue remains a challenge because soils are complex systems, where a continuous evolution of minerals and organic soil constituents occurs in response to interactions with waters and vegetation. This study aims to investigate the relevance of short-lived nuclides of U- and Th-series to quantify the transfer times and scheme of radionuclides through a soil - water - plant ecosystem. Activities of (226Ra), (228Ra) and (228Th), as well as the long-lived (232Th), were measured by TIMS and gamma-spectrometry in the major compartments of a forested soil section, i.e.: solid soil fractions (exchangeable fraction, secondary phases and inherited primary minerals), waters (seepage soil waters and a spring further down the watershed) and vegetation (fine and coarse roots of beech trees, young and mature leaves). The matching of these nuclides half-live to bio-geochemical processes time-scale and the relatively good chemical analogy of radium with calcium make these isotopes especially suitable to investigate either time or mechanism of transfers within a soil-water-plant system. Indeed, the (228Ra/226Ra) isotopic ratios strongly differ in the range of samples, allowing quantifying the source and duration transfers. Analyses of the various solid soil fractions demonstrate a full redistribution of Ra isotopes between the inherited minerals and secondary soil phases. However, the transfer of these isotopes to the seepage water or to the tree roots does not follow a simple and obvious scheme. Both primary and secondary phases show to contribute to the dissolved radium. However, depending on the season, the tree leaves degradation also produces up to 70% of dissolved radium. Immobilization of a large part of this radium occurs

  14. THE DEAD-LIVING-MOTHER: MARIE BONAPARTE'S INTERPRETATION OF EDGAR ALLAN POE'S SHORT STORIES.

    PubMed

    Obaid, Francisco Pizarro

    2016-06-01

    Princess Marie Bonaparte is an important figure in the history of psychoanalysis, remembered for her crucial role in arranging Freud's escape to safety in London from Nazi Vienna, in 1938. This paper connects us to Bonaparte's work on Poe's short stories. Founded on concepts of Freudian theory and an exhaustive review of the biographical facts, Marie Bonaparte concluded that the works of Edgar Allan Poe drew their most powerful inspirational force from the psychological consequences of the early death of the poet's mother. In Bonaparte's approach, which was powerfully influenced by her recognition of the impact of the death of her own mother when she was born-an understanding she gained in her analysis with Freud-the thesis of the dead-living-mother achieved the status of a paradigmatic key to analyze and understand Poe's literary legacy. This paper explores the background and support of this hypothesis and reviews Bonaparte's interpretation of Poe's most notable short stories, in which extraordinary female figures feature in the narrative.

  15. THE DEAD-LIVING-MOTHER: MARIE BONAPARTE'S INTERPRETATION OF EDGAR ALLAN POE'S SHORT STORIES.

    PubMed

    Obaid, Francisco Pizarro

    2016-06-01

    Princess Marie Bonaparte is an important figure in the history of psychoanalysis, remembered for her crucial role in arranging Freud's escape to safety in London from Nazi Vienna, in 1938. This paper connects us to Bonaparte's work on Poe's short stories. Founded on concepts of Freudian theory and an exhaustive review of the biographical facts, Marie Bonaparte concluded that the works of Edgar Allan Poe drew their most powerful inspirational force from the psychological consequences of the early death of the poet's mother. In Bonaparte's approach, which was powerfully influenced by her recognition of the impact of the death of her own mother when she was born-an understanding she gained in her analysis with Freud-the thesis of the dead-living-mother achieved the status of a paradigmatic key to analyze and understand Poe's literary legacy. This paper explores the background and support of this hypothesis and reviews Bonaparte's interpretation of Poe's most notable short stories, in which extraordinary female figures feature in the narrative. PMID:27194275

  16. Variation in the local population dynamics of the short-lived Opuntia macrorhiza (Cactaceae).

    PubMed

    Haridas, C V; Keeler, Kathleen H; Tenhumberg, Brigitte

    2015-03-01

    Spatiotemporal variation in demographic rates can have profound effects for population persistence, especially for dispersal-limited species living in fragmented landscapes. Long-term studies of plants in such habitats help with understanding the impacts of fragmentation on population persistence but such studies are rare. In this work, we reanalyzed demographic data from seven years of the short-lived cactus Opuntia macrorhiza var. macrorhiza at five plots in Boulder, Colorado. Previous work combining data from all years and all plots predicted a stable population (deterministic log lamda approximately 0). This approach assumed that all five plots were part of a single population. Since the plots were located in a suburban-agricultural interface separated by highways, grazing lands, and other barriers, and O. macrorhiza is likely dispersal limited, we analyzed the dynamics of each plot separately using stochastic matrix models assuming each plot represented a separate population. We found that the stochastic population growth rate log lamdaS varied widely between populations (log lamdaS = 0.1497, 0.0774, -0.0230, -0.2576, -0.4989). The three populations with the highest growth rates were located close together in space, while the two most isolated populations had the lowest growth rates suggesting that dispersal between populations is critical for the population viability of O. macrorhiza. With one exception, both our prospective (stochastic elasticity) and retrospective (stochastic life table response experiments) analysis suggested that means of stasis and growth, especially of smaller plants, were most important for population growth rate. This is surprising because recruitment is typically the most important vital rate in a short-lived species such as O. macrorhiza. We found that elasticity to the variance was mostly negligible, suggesting that O. macrorhiza populations are buffered against large temporal variation. Finally, single-year elasticities to means

  17. Consequences of extreme life history traits on population persistence: do short-lived gobies face demographic bottlenecks?

    NASA Astrophysics Data System (ADS)

    Lefèvre, Carine D.; Nash, Kirsty L.; González-Cabello, Alonso; Bellwood, David R.

    2016-06-01

    The majority of coral reef goby species are short-lived, with some highly abundant species living less than 100 d. To understand the role and consequences of this extreme life history in shaping coral reef fish populations, we quantitatively documented the structure of small reef fish populations over a 26-month period (>14 short-lived fish generations) at an inshore reef on the Great Barrier Reef, Australia. Most species with life spans >1 yr, such as pomacentrids, exhibited a peak in recruitment during the austral summer, driving seasonal changes in the small fish community composition. In contrast, there were no clear changes in goby community composition, despite the abundance of short-lived, high turnover species. Species of Eviota, the most abundant gobiid genus observed, showed remarkably similar demographic profiles year-round, with consistent densities of adults as well as recently recruited juveniles. Our results demonstrate ongoing recruitment of these small cryptic fishes, which appears to compensate for an exceptionally short life span on the reef. Our results suggest that gobiid populations are able to overcome demographic limitations, and by maintaining reproduction, larval survival and recruitment throughout the year, they may avoid population bottlenecks. These findings also underline the potential trophodynamic importance of these small species; because of this constant turnover, Eviota species and other short-lived fishes may be particularly valuable contributors to the flow of energy on coral reefs, underpinning the year-round trophic structure.

  18. {beta}-decay half-lives of new neutron-rich isotopes of elements from Pm to Tb

    SciTech Connect

    Ichikawa, S.; Asai, M.; Tsukada, K.; Nishinaka, I.; Nagame, Y.; Osa, A.; Sakama, M.; Oura, Y.; Kojima, Y.; Shibata, M.; Kawade, K.

    1999-11-16

    Eight new neutron-rich lanthanide isotopes produced in the proton-induced fission of {sup 238}U have been identified using the JAERI on-line isotope separator (JAERI-ISOL) coupled to a gas-jet transport system. For six of these, each half-life was determined: {sup 159}Pm (2{+-}1 s), {sup 161}Sm (4.8{+-}0.8 s), {sup 165}Gd (10.3{+-}1.6 s), {sup 166}Tb (21{+-}6 s), {sup 167}Tb (19.4{+-}2.7 s) and {sup 168}Tb (8.2{+-}1.3 s). The observed half-lives were compared with theoretical calculations. The recent calculation by the gross theory with the new one-particle strength function shows quite good agreement with the experimental half-lives.

  19. {beta}-Decay Half-Lives of New Neutron-Rich Isotopes of Elements from Pm to Tb

    SciTech Connect

    S. Ichikawa; M. Asai; K. Tsukada; A. Osa; M. Sakama; Y. Kojima; M. Shibata; I. Nishinaka; Y. Nagame; Y. Oura; K. Kawade

    1999-12-31

    Eight new neutron-rich lanthanide isotopes produced in the proton-induced fission of {sup 238}U have been identified using the JAERI on-line isotope separator (JAERI-ISOL) coupled to a gas-jet transport system. For six of these, each half-life was determined: {sup 159}Pm (2 {+-} 1 s), {sup 161}Sm (4.8 {+-} 0.8 s), {sup 165}Gd (10.3 {+-} 1.6 s), {sup 166}Tb (21 {+-} 6 s), {sup 167}Tb (19.4 {+-} 2.7 s) and {sup 168}Tb (8.2 {+-} 1.3 s). The observed half-lives were compared with theoretical calculations. The recent calculation by the gross theory with the new one-particle strength function shows quite good agreement with the experimental half-lives.

  20. A proposal for assessing study quality: Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument

    PubMed Central

    LaKind, Judy S.; Sobus, Jon R.; Goodman, Michael; Barr, Dana Boyd; Fürst, Peter; Albertini, Richard J.; Arbuckle, Tye E.; Schoeters, Greet; Tan, Yu-Mei; Teeguarden, Justin; Tornero-Velez, Rogelio; Weisel, Clifford P.

    2015-01-01

    The quality of exposure assessment is a major determinant of the overall quality of any environmental epidemiology study. The use of biomonitoring as a tool for assessing exposure to ubiquitous chemicals with short physiologic half-lives began relatively recently. These chemicals present several challenges, including their presence in analytical laboratories and sampling equipment, difficulty in establishing temporal order in cross-sectional studies, short- and long-term variability in exposures and biomarker concentrations, and a paucity of information on the number of measurements required for proper exposure classification. To date, the scientific community has not developed a set of systematic guidelines for designing, implementing and interpreting studies of short-lived chemicals that use biomonitoring as the exposure metric or for evaluating the quality of this type of research for WOE assessments or for peer review of grants or publications. We describe key issues that affect epidemiology studies using biomonitoring data on short-lived chemicals and propose a systematic instrument – the Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument – for evaluating the quality of research proposals and studies that incorporate biomonitoring data on short-lived chemicals. Quality criteria for three areas considered fundamental to the evaluation of epidemiology studies that include biological measurements of short-lived chemicals are described: 1) biomarker selection and measurement, 2) study design and execution, and 3) general epidemiological study design considerations. We recognize that the development of an evaluative tool such as BEES-C is neither simple nor non-controversial. We hope and anticipate that the instrument will initiate further discussion/debate on this topic. PMID:25137624

  1. A proposal for assessing study quality: Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument.

    PubMed

    LaKind, Judy S; Sobus, Jon R; Goodman, Michael; Barr, Dana Boyd; Fürst, Peter; Albertini, Richard J; Arbuckle, Tye E; Schoeters, Greet; Tan, Yu-Mei; Teeguarden, Justin; Tornero-Velez, Rogelio; Weisel, Clifford P

    2014-12-01

    The quality of exposure assessment is a major determinant of the overall quality of any environmental epidemiology study. The use of biomonitoring as a tool for assessing exposure to ubiquitous chemicals with short physiologic half-lives began relatively recently. These chemicals present several challenges, including their presence in analytical laboratories and sampling equipment, difficulty in establishing temporal order in cross-sectional studies, short- and long-term variability in exposures and biomarker concentrations, and a paucity of information on the number of measurements required for proper exposure classification. To date, the scientific community has not developed a set of systematic guidelines for designing, implementing and interpreting studies of short-lived chemicals that use biomonitoring as the exposure metric or for evaluating the quality of this type of research for WOE assessments or for peer review of grants or publications. We describe key issues that affect epidemiology studies using biomonitoring data on short-lived chemicals and propose a systematic instrument--the Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument--for evaluating the quality of research proposals and studies that incorporate biomonitoring data on short-lived chemicals. Quality criteria for three areas considered fundamental to the evaluation of epidemiology studies that include biological measurements of short-lived chemicals are described: 1) biomarker selection and measurement, 2) study design and execution, and 3) general epidemiological study design considerations. We recognize that the development of an evaluative tool such as BEES-C is neither simple nor non-controversial. We hope and anticipate that the instrument will initiate further discussion/debate on this topic.

  2. First Results Using a New Technology for Measuring Masses of Very Short-Lived Nuclides with Very High Accuracy: the MISTRAL Program at ISOLDE

    SciTech Connect

    C. Monsanglant; C. Toader; G. Audi; G. Bollen; C. Borcea; G. Conreur; R. Cousin; H. Doubre; M. Duma; M. Jacotin; S. Henry; J.-F. Kepinski; H.-J. Kluge; G. Lebee; G. Le Scornet; D. Lunney; M. de Saint Simon; C. Scheidenberger; C. Thibault

    1999-12-31

    MISTRAL is an experimental program to measure masses of very short-lived nuclides (T{sub 1/2} down to a few ms), with a very high accuracy (a few 10{sup -7}). There were three data taking periods with radioactive beams and 22 masses of isotopes of Ne, Na{clubsuit}, Mg, Al{clubsuit}, K, Ca, and Ti were measured. The systematic errors are now under control at the level of 8x10{sup -7}, allowing to come close to the expected accuracy. Even for the very weakly produced {sup 30}Na (1 ion at the detector per proton burst), the final accuracy is 7x10{sup -7}.

  3. Asymptotic Giant Branch stars as a source of short-lived radioactive nuclei in the solar nebula

    NASA Technical Reports Server (NTRS)

    Wasserburg, G. J.; Busso, M.; Gallino, R.; Raiteri, C. M.

    1994-01-01

    We carried out a theoretical evaluation of the contribution of Asymptotic Giant Branch (AGB) stars to some short-lived (10(exp 6) less than or equal to Tau-bar less than or equal to 2 x 10(exp 7) yr) isotopes in the Interstellar Medium (ISM) and in the early solar system using stellar model calculations for thermally pulsing evolutionary phases of low-mass stars. The yields of s-process nuclei in the convective He-shell for different neutron exposures tau(sub 0) were obtained, and AGB stars were shown to produce several radioactive nuclei (especially Pd-107, Pb-205, Fe-60, Zr-93, Tc-99, Cs-135, and Hf-182) in diferent amounts. Assuming either contamination of the solar nebula from a single AGB star or models for continuous injection and mixing from many stars into the ISM, we calculate the ratios of radioactive to stable nuclei at the epoch of the Sun's formation. The dilution factor between the AGB ejecta and the early solar system matter is obtained by matching the observed Pd-107/Pd-108 and depends on the value of tau(sub 0). It is found that small masses M(sub He) of He-shell material (10(exp -4)-10(exp -7) solar mass) enriched in s-process nuclei are sufficient to contaminate 1 solar mass of the ISM to produce the Pd-107 found in the early solar system. Predictions are made for all of the other radioactive isotopes. The optimal model to explain several observed radioactive species at different states of the proto-solar nebula involves a single AGB star with a low neutron exposure (tau(sub 0) = 0.03 mbarn(sup -1)) which contaminated the cloud with a dilution factor of M(sub He)/solar mass approximately 1.5 x 10(exp -4). This will also contribute newly synthesized stable s-process nuclei in the amount of approximately 10(exp -4) of their abundances already present in the proto-solar cloud. Variations in the degree of homogenization (approximately 30%) of the injected material may account for some of the small general isotopic anomalies found in meteorites. It is

  4. Optimizing the Delivery of Short-Lived Alpha Particle-Emitting Isotopes to Solid Tumors

    SciTech Connect

    Adams, Gregory P.

    2004-11-24

    The underlying hypothesis of this project was that optimal alpha emitter-based radioimmunotherapy (RAIT) could be achieved by pairing the physical half-life of the radioisotope to the biological half-life of the targeting vehicle. The project had two specific aims. The first aim was to create and optimize the therapeutic efficacy of 211At-SAPS-C6.5 diabody conjugates. The second aim was to develop bispecific-targeting strategies that increase the specificity and efficacy of alpha-emitter-based RAIT. In the performance of the first aim, we created 211At-SAPS-C6.5 diabody conjugates that specifically targeted the HER2 tumor associated antigen. In evaluating these immunoconjugates we determined that they were capable of efficient tumor targeting and therapeutic efficacy of established human tumor xenografts growing in immunodeficient mice. We also determined that therapeutic doses were associated with late renal toxicity, likely due to the role of the kidneys in the systemic elimination o f these agents. We are currently performing more studies focused on better understanding the observed toxicity. In the second aim, we successfully generated bispecific single-chain Fv (bs-scFv) molecules that co-targeted HER2 and HER3 or HER2 and HER4. The in vitro kinetics and in vivo tumor-targeting properties of these molecules were evaluated. These studies revealed that the bs-scFv molecules selectively localized in vitro on tumor cells that expressed both antigens and were capable of effective tumor localization in in vivo studies.

  5. AGB stars as a source of short-lived radioactive nuclei in the solar nebula

    NASA Technical Reports Server (NTRS)

    Wasserburg, G. J.; Gallino, R.; Busso, M.; Raiteri, C. M.

    1993-01-01

    The purpose is to estimate the possible contribution of some short-lived nuclei to the early solar nebula from asymptotic giant branch (AGB) sources. Low mass (1 to 3 solar mass) AGB stars appear to provide a site for synthesis of the main s process component for solar system material with an exponential distribution of neutron irradiations varies as exp(-tau/tau(sub 0)) (where tau is the time integrated neutron flux with a mean neutron exposure tau(sub 0)) for solar abundances with tau(sub 0) = 0.28 mb(sup -1). Previous workers estimated the synthesis of key short-lived nuclei which might be produced in AGB stars. While these calculations exhibit the basic characteristics of nuclei production by neutron exposure, there is need for a self-consistent calculation that follows AGB evolution and takes into account the net production from a star and dilution with the cloud medium. Many of the general approaches and the conclusions arrived at were presented earlier by Cameron. The production of nuclei for a star of 1.5 solar mass during the thermal pulsing of the AGB phase was evaluated. Calculations were done for a series of thermal pulses with tau(sub 0) = 0.12 and 0.28 mb(sup -1). These pulses involve s nucleosynthesis in the burning shell at the base of the He zone followed by the ignition of the H burning shell at the top of the He zone. After about 10-15 cycles the abundances of the various nuclei in the He zone become constant. Computations of the abundances of all nuclei in the He zone were made following Gallino. The mass of the solar nebula was considered to consist of some initial material of approximately solar composition plus some contributions from AGB stars. The ratios of the masses required from the AGB He burning zone to the ISM necessary to produce the observed value of Pd-107/Pd-108 in the early solar system were calculated and this dilution factor was applied to all other relevant nuclei.

  6. The impacts of short-lived ozone precursors on climate and air quality

    NASA Astrophysics Data System (ADS)

    Fry, Meridith McGee

    Human emissions of short-lived ozone precursors not only degrade air quality and health, but indirectly affect climate via chemical effects on ozone, methane, and aerosols. Some have advocated for short-lived air pollutants in near-term climate mitigation strategies, in addition to national air quality programs, but their radiative forcing (RF) impacts are uncertain and vary based on emission location. In this work, global chemical transport modeling is combined with radiative transfer modeling to study the impacts of regional ozone precursor emissions (NOx, CO, and NMVOCs) on climate, via changes in ozone, methane, and sulfate, and on regional and global air quality. The first study evaluates NOx, CO, and NMVOC emission reductions from four regions across an ensemble of models, finding that NMVOC and CO reductions from all four regions cool climate (negative RF) by decreasing ozone and methane, while improving air quality. NOx and NMVOC global warming potentials (GWPs), a measure of the relative radiative effects of individual climate forcers, vary strongly among regions, while CO GWPs show less variability. The second and third studies investigate further the RF and air quality impacts of CO and NMVOC emission reductions from 10 world regions. The greatest benefits to RF and air quality (per unit emissions) are achieved by CO reductions from the tropics, due to more active photochemistry and convection. CO GWPs are fairly independent of the reduction region (GWP20: 3.71 to 4.37; GWP100: 1.26 to 1.44), while NMVOC GWPs are more variable (GWP 20: -1.13 to 18.9; GWP100: 0.079 to 6.05). Accounting for additional forcings from CO and NMVOC emissions would likely change RF and GWP estimates. Regionally-specific GWPs for NOx and NMVOCs and a globally-uniform GWP for CO may allow these gases to be included in a multi-gas emissions trading framework, and enable comprehensive strategies for meeting climate and air quality goals simultaneously. Future research could

  7. Incorporation of short-lived (10)Be in a calcium-aluminum-rich inclusion from the allende meteorite

    PubMed

    McKeegan; Chaussidon; Robert

    2000-08-25

    Enrichments in boron-10/boron-11 in a calcium-aluminum-rich inclusion from the Allende carbonaceous chondrite are correlated with beryllium/boron in a manner indicative of the in situ decay of short-lived beryllium-10. Because this radionuclide is produced only by nuclear spallation reactions, its existence in early solar system materials attests to intense irradiation processes in the solar nebula. The particle fluence inferred from the initial beryllium-10/beryllium-9 is sufficient to produce other short-lived nuclides, calcium-41 and manganese-53, found in meteorites, but the high canonical abundance of aluminum-26 may still require seeding of the solar system by radioactive stellar debris.

  8. Higher Accuracy Measurements of Photochemical Properties of Very Short-Lived Substances.

    NASA Astrophysics Data System (ADS)

    Orkin, V. L.; Khamaganov, V. G.; Kurylo, M. J., III

    2015-12-01

    Despite the broad applicability of simple fully halogenated hydrocarbons in various industries, the production and use of bromo(chloro)fluorocarbons (Halons) and chlorofluorocarbons (CFCs) has been phased out because of the danger they pose to the Earth's stratospheric ozone layer. In addition, all halogen-containing hydrocarbons are infrared active gases because of their strong absorption bands in the region of the atmospheric transparency window between ca. 8 and 12 mm that can affect the Earth's radiation balance. However, the effort to find replacements continues to return to bromine (chlorine)-containing compounds because of their excellent properties as industrial solvents and cleaning agents and especially because of bromine efficiency as a chemically active flame suppressant. The primary approach to this problem has been to test candidate replacement compounds that have very short atmospheric lifetimes and therefore substantially reduced ozone depleting and radiative impacts. Reactions with hydroxyl radicals (OH) and photolysis are the main processes dictating the compound residence time in the atmosphere for a majority of trace gases. In case of very short-lived substances (VSLS) their reaction with OH dictates both the atmospheric lifetime and active halogen release. Therefore, the accuracy of OH kinetic data is of primary importance for the purpose of comprehensive atmospheric modeling of compound's impact on the atmosphere, such as in ozone depletion and climate change. We demonstrated the ability to determine the OH reaction rate constants over the temperature range of atmospheric interest with the total uncertainty of ~2-3%, thus making laboratory measurements a negligible source of uncertainty in atmospheric modeling. These studies revealed the different reactivity of molecular isomers toward OH and a non-Arrhenius behavior of the temperature dependence to be a rather common kinetic feature of the OH reactivity, which can be accounted for in

  9. Metrics for comparing climate impacts of short- and long-lived climate forcing agents

    NASA Astrophysics Data System (ADS)

    Fuglestvedt, J.; Berntsen, T.

    2013-12-01

    Human activities emit a wide variety of gases and aerosols, with different characteristics that influence both air quality and climate. The emissions affect climate both directly and indirectly and operate on both short and long timescales. Tools that allow these emissions to be placed on a common scale in terms of climate impact, i.e. metrics, have a number of applications (e.g. agreements and emission trading schemes, when considering potential trade-offs between changes in emissions). The Kyoto Protocol compares greenhouse gas (GHG) emissions using the Global Warming Potential (GWP) over a 100 year time-horizon. The IPCC First Assessment Report states the GWP was presented to illustrate the difficulties in comparing GHGs. There have been many critiques of the GWP and several alternative emission metrics have been proposed, but there has been little focus on understanding the linkages between, and interpretations of, different emission metrics. Furthermore, the capability to compare components with very different lifetimes and temporal behaviour needs consideration. The temperature based metrics (e.g. the Global Temperature change Potential (GTP)) require a model for the temperature response, and additional uncertainty is thus introduced. Short-lived forcers may also give more spatially heterogeneous responses, and the possibilities to capture these spatial variations by using other indicators than global mean RF or temperature change in metrics will be discussed. The ultimate choice of emission metric(s) and time-horizon(s) should, however, depend on the objectives of climate policy. Alternatives to the current 'multi-gas and single-basket' approach will also be explored and discussed (e.g. how a two-target approach may be implemented using a two-basket approach). One example is measures to reduce near-term rate of warming and long-term stabilization which can be implemented through two separate targets and two baskets with separate set of metrics for each

  10. Trace element and isotopic geochemistry of Franciscan graywackes with implications for short time of recycling of detritus and interaction of continental sediments with metabasites during subduction

    NASA Astrophysics Data System (ADS)

    Ghatak, A.; Basu, A. R.; Wakabayashi, J.

    2011-12-01

    Franciscan isotopic compositions resembling older Great Valley Group rocks. Although there is much scatter in the collective dataset, these results suggest that the burial-exhumation cycles that recycled Franciscan clastic material were short lived. A comparison of the trace element and isotopic ratios of the Franciscan graywackes with those of Franciscan metabasites reaffirms the conclusion in several of our recent studies that the metabasites were not chemically modified by interaction with fluids derived from continental sediments during subduction and exhumation.

  11. Relationships between the distribution and stable isotopic composition of living benthic foraminifera and cold methane seep biogeochemistry in Monterey Bay, California

    NASA Astrophysics Data System (ADS)

    Rathburn, Anthony E.; PéRez, M. Elena; Martin, Jonathan B.; Day, Shelley A.; Mahn, Chris; Gieskes, Joris; Ziebis, Wiebke; Williams, David; Bahls, Amanda

    2003-12-01

    As part of an ongoing effort to explore the use of foraminifera as a means to assess modern and ancient methane release, we compared ambient pore water chemistry with the distribution and stable isotopic composition of living (rose Bengal stained) foraminifera in MBARI ROV Ventana tube cores taken from modern seepage areas (about 1000 m water depth) in Monterey Bay, California. Benthic foraminiferal isotopic differences between sites clearly indicate that methane-influenced pore waters affect foraminiferal distributions and carbonate isotope geochemistry. Carbon isotope signatures of living benthic foraminifera did not conform to the very negative (-30 to -48‰), methane-influenced carbon isotope values of the pore waters they live in. Instead, the influence of methane seep pore waters was reflected in the greater range and carbon isotopic variability of living seep foraminifera compared with published δ13C values of foraminifera living in nonseep habitats. It is not clear what relative influences biological, ecological, and physical factors have on the carbon isotopic signatures observed in seep foraminifera. Substantial carbon isotope differences can exist between individuals of the same seep species. For instance, δ13C values of living Globobulimina pacifica varied by as much as 2.9‰ between seeps within 8 km of each other, whereas δ13C values of living Uvigerina peregrina varied by as much as 1.95‰ within the same seep. Provided there is no diagenetic alteration of the test carbonate, isotopic results of individual seep foraminifera support the hypothesis that foraminifera can be used to assess past and present methane seepage.

  12. Limits to the sensitivity of living benthic foraminifera to pore water carbon isotope anomalies in methane vent environments

    NASA Astrophysics Data System (ADS)

    Herguera, J. C.; Paull, C. K.; Perez, E.; Ussler, W.; Peltzer, E.

    2014-03-01

    Episodic 13C depletions in the carbon isotopic composition of benthic foraminiferal tests preserved in the stratigraphic record have been interpreted as an active incorporation of methane-derived carbon. Understanding the extent to which these isotope excursions reflect basin-wide fluxes of methane carbon to bottom waters versus a local supply of methane carbon within the sediments in which benthic foraminifera live, or a postmortem diagenetic imprint is critical to the interpretation of δ13C paleoceanographic proxies. Here we evaluate the impact of chemical gradients measured in pore waters adjacent to active methane vents on carbon assimilation by living benthic foraminifera and show that those living near methane vents do not assimilate the distinctly 13C depleted methane-derived dissolved inorganic carbon into their tests from the pore water in which they were found. Our observations can be explained by the recently articulated physiological limits imposed on deep-sea fauna by low-oxygen and high-pCO2 environments. Understanding the importance of the different processes involved in the observed disequilibrium between the carbon isotopic composition of the benthic forams and the pore waters where they were found has important implications on the reliability of carbon isotopic composition of benthic foraminifera for paleoceanographic reconstructions. In particular, the observation on the inhospitability of these environments for benthic foraminifera at least for reproduction and growth raises the issue on the overprint either in the late adult stages of foraminifera that grew in a different neighboring environment or during early diagenesis in these geochemically active environments.

  13. Development of a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers

    NASA Astrophysics Data System (ADS)

    Kiser, Matthew R.

    Over the past 200 years, the Earth's atmospheric carbon dioxide (CO 2) concentration has increased by more than 35%, and climate experts predict that CO2 levels may double by the end of this century. Understanding the mechanisms of resource management in plants is fundamental for predicting how plants will respond to the increase in atmospheric CO 2. Plant productivity sustains life on Earth and is a principal component of the planet's system that regulates atmospheric CO2 concentration. As such, one of the central goals of plant science is to understand the regulatory mechanisms of plant growth in a changing environment. Short-lived positron-emitting radiotracer techniques provide time-dependent data that are critical for developing models of metabolite transport and resource distribution in plants and their microenvironments. To better understand the effects of environmental changes on resource transport and allocation in plants, we have developed a system for real-time measurements of rnetabolite transport in plants using short-lived positron-emitting radio-tracers. This thesis project includes the design, construction, and demonstration of the capabilities of this system for performing real-time measurements of metabolite transport in plants. The short-lived radiotracer system described in this dissertation takes advantage of the combined capabilities and close proximity of two research facilities at. Duke University: the Triangle Universities Nuclear Laboratory (TUNL) and the Duke University Phytotron, which are separated by approximately 100 meters. The short-lived positron-emitting radioisotopes are generated using the 10-MV tandem Van de Graaff accelerator located in the main TUNL building, which provides the capability of producing short-lived positron-emitting isotopes such as carbon-11 (11C: 20 minute half-life), nitrogen-13 (13N; 10 minute half-life), fluorine-18 (18F; 110 minute half-life), and oxygen-15 (15O; 2 minute half-life). The radioisotopes may

  14. Age-specific mortality and short-term changes in the standard of living: Sweden, 1751-1859.

    PubMed

    Bengtsson, T; Ohlsson, R

    1985-11-01

    "The response of mortality to short-term changes in real wages is analyzed here not just in its own right but more particularly as an indicator of long-term shifts in the general standard of living. It is hypothesized that the response would have been stronger the lower the standard of living. The relationship between age-specific mortality levels and real-wage series for Sweden 1751-1860 is analyzed using a distributed-lag model and spectral analysis. The results suggest a real shift in the material standard of living during the period." (summary in FRE) PMID:12314070

  15. Age-dependent decline in fin regenerative capacity in the short-lived fish Nothobranchius furzeri

    PubMed Central

    Wendler, Sebastian; Hartmann, Nils; Hoppe, Beate; Englert, Christoph

    2015-01-01

    The potential to regenerate declines with age in a wide range of organisms. A popular model system to study the mechanisms of regeneration is the fin of teleost fish, which has the ability to fully regrow upon amputation. Here, we used the short-lived killifish Nothobranchius furzeri to analyse the impact of aging on fin regeneration in more detail. We observed that young fish were able to nearly completely (98%) regenerate their amputated caudal fins within 4 weeks, whereas middle-aged fish reached 78%, old fish 57% and very old fish 46% of their original fin size. The difference in growth rate between young and old fish was already significant at 3 days post amputation (dpa) and increased with time. We therefore hypothesized that early events are crucial for the age-related differences in regenerative capacity. Indeed, we could observe a higher percentage of proliferating cells in early regenerating fin tissue of young fish compared with aged fish and larger fractions of apoptotic cells in aged fish. Furthermore, young fish showed peak upregulation of several genes involved in fgf and wnt/β-catenin signalling at an earlier time point than old fish. Our findings suggest that regenerative processes are initiated earlier and that regeneration overall is more efficient in younger fish. PMID:26121607

  16. A Reevaluation of the Contribution of Very Short Lived Bromocarbons to Stratospheric Bromine Loading

    NASA Astrophysics Data System (ADS)

    Wales, P.; Salawitch, R. J.; Canty, T. P.; Mount, G. H.; Spinei, E.; Suleiman, R. M.; Chance, K.; McPeters, R. D.; Bhartia, P. K.; Kurosu, T. P.; Simpson, W. R.; Donohoue, D.; Johnson, B. J.; Kinnison, D. E.; Tilmes, S.; Choi, S.; Joiner, J.

    2015-12-01

    The Aura Ozone Monitoring Instrument (OMI) has provided global measurements of total column BrO over the past decade. Interpreting the distribution of total column BrO between the stratosphere and troposphere depends strongly on the contribution of very short lived (VSL) bromocarbons to stratospheric inorganic bromine (Bry). Salawitch et al. (2010) suggested 7 to 12 ppt of Bry must be supplied to the lower stratosphere from the decomposition of VSL bromocarbons to accurately represent the variation of total column OMI BrO with total column O3. Here we will re-evaluate this recommendation in light of ground-based total column BrO measurements obtained over Fairbanks, Alaska using a multifunction differential optical absorption spectroscopy (MFDOAS) instrument during the spring of 2011. Additionally, we will assess how modifications to kinetics regulating the partitioning between BrO and BrONO2 proposed by Kreycy et al. (2013) affect the VSL Bry estimate as well as the modeled diurnal variation in BrO. ReferencesKreycy, S. et al. Atmos. Chem. Phys. 2013, 13, 6263-6274, doi:10.5194/acp-13-6263-2013. Salawitch, R.J. et al. Geophys. Res. Lett. 2010, 37, L21805, doi:10.1029/2010GL043798.

  17. Short-Lived Buildings in China: Impacts on Water, Energy, and Carbon Emissions.

    PubMed

    Cai, Wenjia; Wan, Liyang; Jiang, Yongkai; Wang, Can; Lin, Lishen

    2015-12-15

    This paper has changed the vague understanding that "the short-lived buildings have huge environmental footprints (EF)" into a concrete one. By estimating the annual floor space of buildings demolished and calibrating the average building lifetime in China, this paper compared the EF under various assumptive extended buildings' lifetime scenarios based on time-series environmental-extended input-output model. Results show that if the average buildings' lifetime in China can be extended from the current 23.2 years to their designed life expectancy, 50 years, in 2011, China can reduce 5.8 Gt of water withdrawal, 127.1 Mtce of energy consumption, and 426.0 Mt of carbon emissions, each of which is equivalent to the corresponding annual EF of Belgium, Mexico, and Italy. These findings will urge China to extend the lifetime of existing and new buildings, in order to reduce the EF from further urbanization. This paper also verifies that the lifetime of a product or the replacement rate of a sector is a very important factor that influences the cumulative EF. When making policies to reduce the EF, adjusting people's behaviors to extend the lifetime of products or reduce the replacement rate of sectors may be a very simple and cost-effective option.

  18. Short-Lived HF Molecules in Superionic Hydrogen Fluoride at Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Tsumuraya, Kazuo; Ohde, Yoshiyuki; Oshimi, Tadaaki

    2015-02-01

    The first principles molecular dynamics study enables us to elucidate the existence of short-lived HF molecules in the superionic hydrogen fluoride at an extreme high pressure and a temperature. Three fourth of the immobile fluorines constructs the molecules with lifetime of 8 fs. The ionized fluorines form weak HF bond with the proton in the nearest HF molecule of which the lifetime is 3 fs. The covalent and the Coulomb bonds between the fluorines and the protons form indirect covalent and indirect Coulomb attractions between the di-interstitial protons on the mid-fluorines. The attractions reduce the Haven's ratio of the protons. The absence of the proton dimers indicates a failure of the caterpillar diffusion model or the Frenkel-Kontorova chain model for the superionic diffusion of the protons. The incompletely ionized cations and anions reduce their Coulomb attractions which induce the sublattice melting of smaller size and smaller mass of the protons than the fluorines. The electronic states of the fluoride are intermediate between the ionic crystals and the covalent bonded molecular crystals. The superionic conductors are classified into three groups: they are molecular type, covalent metalloid type, and metallic type conductors.

  19. Short-Lived Buildings in China: Impacts on Water, Energy, and Carbon Emissions.

    PubMed

    Cai, Wenjia; Wan, Liyang; Jiang, Yongkai; Wang, Can; Lin, Lishen

    2015-12-15

    This paper has changed the vague understanding that "the short-lived buildings have huge environmental footprints (EF)" into a concrete one. By estimating the annual floor space of buildings demolished and calibrating the average building lifetime in China, this paper compared the EF under various assumptive extended buildings' lifetime scenarios based on time-series environmental-extended input-output model. Results show that if the average buildings' lifetime in China can be extended from the current 23.2 years to their designed life expectancy, 50 years, in 2011, China can reduce 5.8 Gt of water withdrawal, 127.1 Mtce of energy consumption, and 426.0 Mt of carbon emissions, each of which is equivalent to the corresponding annual EF of Belgium, Mexico, and Italy. These findings will urge China to extend the lifetime of existing and new buildings, in order to reduce the EF from further urbanization. This paper also verifies that the lifetime of a product or the replacement rate of a sector is a very important factor that influences the cumulative EF. When making policies to reduce the EF, adjusting people's behaviors to extend the lifetime of products or reduce the replacement rate of sectors may be a very simple and cost-effective option. PMID:26561867

  20. Climatologies Of Stratospheric Short-Lived Species From ODIN/SMR: Methodology For CLO

    NASA Astrophysics Data System (ADS)

    Khosravi, M.; Urban, J.; Murtah, D. P.; Brohede, S.

    2013-12-01

    The Sub-Millimetre Radiometer (SMR) on board the Odin satellite has been measuring short-lived stratospheric species such as chlorine monoxide (ClO) since Odin's launch in 2001. Odin/SMR at its sun-synchronous orbit measures at certain local times observations around sunrise and sunset at the equator. Due to the drift of Odin's orbit in local solar time and the fact that measurements are done at different local times, a correction is required before a monthly zonal mean climatology can be calculated and trends of ClO can be evaluated. To deal with this, scaling factors are calculated using a photo-chemical box model for correction of the mixing ratios respective to a reference time. The uncertainties and limitations of this method are estimated by checking the internal consistency of the results, so that comparing the scaled a.m. ClO time-series to p.m. scaled time- series should give the same results. We found out that scaling SMR ClO to the ascending time of Microwave Limb Sounder (MLS) as reference at about 1.30 a.m. at the equator gives better result compared to the scaling ClO to MLS descending node at about 1.30. p.m. The time series calculated for the morning SMR ClO scaled (to 1.30 a.m.) agrees with the evening ClO scaled.

  1. Magneto-photocurrent in organic photovoltaic cells; the effect of short-lived charge transfer states

    NASA Astrophysics Data System (ADS)

    Ehrenfreund, Eitan; Devir-Wolfman, A.; Khachatryan, B.; Gautam, B.; Tessler, N.; Vardeny, Z. V.

    2014-03-01

    The spin degrees of freedom are responsible for the magnetic field effects in organic devices at low magnetic fields. The MFE is formed via a variety of spin-mixing mechanisms, such as the hyperfine (typical strength: Bhf<0.003 T), triplet-polaron or triplet-triplet (Btrip<0.1 T) interactions, that limit the response by their respective strength. We report on magneto-photocurrent (MPC) response of bulk hetero-junction organic photovoltaic cells in an extended field range B =0.00005 - 8 Tesla, and found that spin mixing mechanisms are still operative even at the highest fields. In fact, the response MPC(B) can be divided into three main regions, each with a different sign: sharp response that increases with B up to B1 ~ 0.04 T; broad response that decreases with B in the range from B1 to B2 ~ 0.3-0.7 T; and even broader response that increases above B2; this response does not saturate even at 8.5 T. We attribute the latter MPC component to short-lived charge transfer excitons (CTE) where spin-mixing is caused by the difference of the donor/acceptor g factors; a mechanism that is increasingly more effective at high magnetic field. Supported by the US-Israel BSF.

  2. Growth in stratospheric chlorine from short-lived chemicals not controlled by the Montreal Protocol

    NASA Astrophysics Data System (ADS)

    Hossaini, R.; Chipperfield, M. P.; Saiz-Lopez, A.; Harrison, J. J.; Glasow, R.; Sommariva, R.; Atlas, E.; Navarro, M.; Montzka, S. A.; Feng, W.; Dhomse, S.; Harth, C.; Mühle, J.; Lunder, C.; O'Doherty, S.; Young, D.; Reimann, S.; Vollmer, M. K.; Krummel, P. B.; Bernath, P. F.

    2015-06-01

    We have developed a chemical mechanism describing the tropospheric degradation of chlorine containing very short-lived substances (VSLS). The scheme was included in a global atmospheric model and used to quantify the stratospheric injection of chlorine from anthropogenic VSLS ( ClyVSLS) between 2005 and 2013. By constraining the model with surface measurements of chloroform (CHCl3), dichloromethane (CH2Cl2), tetrachloroethene (C2Cl4), trichloroethene (C2HCl3), and 1,2-dichloroethane (CH2ClCH2Cl), we infer a 2013 ClyVSLS mixing ratio of 123 parts per trillion (ppt). Stratospheric injection of source gases dominates this supply, accounting for ˜83% of the total. The remainder comes from VSLS-derived organic products, phosgene (COCl2, 7%) and formyl chloride (CHClO, 2%), and also hydrogen chloride (HCl, 8%). Stratospheric ClyVSLS increased by ˜52% between 2005 and 2013, with a mean growth rate of 3.7 ppt Cl/yr. This increase is due to recent and ongoing growth in anthropogenic CH2Cl2—the most abundant chlorinated VSLS not controlled by the Montreal Protocol.

  3. Seasonal assemblages and short-lived blooms in coastal north-west Atlantic Ocean bacterioplankton.

    PubMed

    El-Swais, Heba; Dunn, Katherine A; Bielawski, Joseph P; Li, William K W; Walsh, David A

    2015-10-01

    Temperate oceans are inhabited by diverse and temporally dynamic bacterioplankton communities. However, the role of the environment, resources and phytoplankton dynamics in shaping marine bacterioplankton communities at different time scales remains poorly constrained. Here, we combined time series observations (time scales of weeks to years) with molecular analysis of formalin-fixed samples from a coastal inlet of the north-west Atlantic Ocean to show that a combination of temperature, nitrate, small phytoplankton and Synechococcus abundances are best predictors for annual bacterioplankton community variability, explaining 38% of the variation. Using Bayesian mixed modelling, we identified assemblages of co-occurring bacteria associated with different seasonal periods, including the spring bloom (e.g. Polaribacter, Ulvibacter, Alteromonadales and ARCTIC96B-16) and the autumn bloom (e.g. OM42, OM25, OM38 and Arctic96A-1 clades of Alphaproteobacteria, and SAR86, OM60 and SAR92 clades of Gammaproteobacteria). Community variability over spring bloom development was best explained by silicate (32%)--an indication of rapid succession of bacterial taxa in response to diatom biomass--while nanophytoplankton as well as picophytoplankton abundance explained community variability (16-27%) over the transition into and out of the autumn bloom. Moreover, the seasonal structure was punctuated with short-lived blooms of rare bacteria including the KSA-1 clade of Sphingobacteria related to aromatic hydrocarbon-degrading bacteria.

  4. Counteracting the climate effects of volcanic eruptions using short-lived greenhouse gases

    NASA Astrophysics Data System (ADS)

    Samset, B. H.; Fuglestvedt, J.; Shine, K. P.

    2014-12-01

    A large volcanic eruption might constitute a climate emergency, significantly altering global temperature and precipitation for several years. Major future eruptions will occur, but their size or timing cannot be predicted. How could global society prepare for, and react to, such emergencies? One possibility is deliberate, coordinated emissions of short-lived greenhouse gases, along a pathway designed to match the climate responses to the eruption. We estimate such an emission pathway, countering a hypothetical eruption three times the size of Mt Pinatubo in 1991. Using a global climate model to evaluate global and regional responses to the eruption, with and without counter emissions, we show that it may be possible to counteract its climate effects, significantly dampening the abrupt impact of the eruption. We then raise practical, financial and ethical aspects related to such a strategy. Designed emissions to counter temporary global cooling would not have the disadvantages associated with more commonly discussed geoengineering to avoid long-term warming. Nevertheless, implementation would still face significant challenges.

  5. A new approach for fluid dynamics simulation: The Short-lived Water Cuboid Particle model

    NASA Astrophysics Data System (ADS)

    Qiao, Changjian; Li, Jiansong; Tian, Zongshun

    2016-09-01

    There are many researches to simulate the fluid which adopt the traditional particle-based approach and the grid-based approach. However, it needs massive storage in the traditional particle-based approach and it is very complicated to design the grid-based approach with the Navier-Stokes Equations or the Shallow Water Equations (SWEs) because of the difficulty of solving equations. This paper presents a new model called the Short-lived Water Cuboid Particle model. It updates the fluid properties (mass and momentum) recorded in the fixed Cartesian grids by computing the weighted sum of the water cuboid particles with a time step life. Thus it is a two-type-based approach essentially, which not only owns efficient computation and manageable memory like the grid-based approach, but also deals with the discontinuous water surface (wet/dry fronts, boundary conditions, etc.) with high accuracy as well as the particle-based approach. The proposed model has been found capable to simulate the fluid excellently for three laboratory experimental cases and for the field case study of the Malpasset dam-break event occurred in France in 1959. The obtained results show that the model is proved to be an alternative approach to simulate the fluid dynamics with a fair accuracy.

  6. Multi-model evaluation of short-lived pollutant distributions over East Asia during summer 2008

    NASA Astrophysics Data System (ADS)

    Quennehen, B.; Raut, J.-C.; Law, K. S.; Ancellet, G.; Clerbaux, C.; Kim, S.-W.; Lund, M. T.; Myhre, G.; Olivié, D. J. L.; Safieddine, S.; Skeie, R. B.; Thomas, J. L.; Tsyro, S.; Bazureau, A.; Bellouin, N.; Daskalakis, N.; Hu, M.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Myriokefalitakis, S.; Quaas, J.; Rumbold, S. T.; Schulz, M.; Cherian, R.; Shimizu, A.; Wang, J.; Yoon, S.-C.; Zhu, T.

    2015-04-01

    The ability of six global and one regional model to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over Asia in summer 2008 is evaluated using satellite and in-situ observations. Whilst ozone precursors (NO2 and CO) are generally underestimated by the models in the troposphere, surface NO2 concentrations are overestimated, suggesting that emissions of NOx are too high. Ozone integrated columns and vertical profiles are generally well modeled, but the global models face difficulties simulating the ozone gradient at the surface between urban and rural environments, pointing to the need to increase model resolution. The accuracy of simulated aerosol patterns over eastern China and northern India varies between the models, and although most of the models reproduce the observed pollution features over eastern China, significant biases are noted in the magnitude of optical properties (aerosol optical depth, aerosol backscatter). These results have important implications for accurate prediction of pollution episodes affecting air quality and the radiative effects of these short-lived climate pollutants over Asia.

  7. Age-dependent decline in fin regenerative capacity in the short-lived fish Nothobranchius furzeri.

    PubMed

    Wendler, Sebastian; Hartmann, Nils; Hoppe, Beate; Englert, Christoph

    2015-10-01

    The potential to regenerate declines with age in a wide range of organisms. A popular model system to study the mechanisms of regeneration is the fin of teleost fish, which has the ability to fully regrow upon amputation. Here, we used the short-lived killifish Nothobranchius furzeri to analyse the impact of aging on fin regeneration in more detail. We observed that young fish were able to nearly completely (98%) regenerate their amputated caudal fins within 4 weeks, whereas middle-aged fish reached 78%, old fish 57% and very old fish 46% of their original fin size. The difference in growth rate between young and old fish was already significant at 3 days post amputation (dpa) and increased with time. We therefore hypothesized that early events are crucial for the age-related differences in regenerative capacity. Indeed, we could observe a higher percentage of proliferating cells in early regenerating fin tissue of young fish compared with aged fish and larger fractions of apoptotic cells in aged fish. Furthermore, young fish showed peak upregulation of several genes involved in fgf and wnt/β-catenin signalling at an earlier time point than old fish. Our findings suggest that regenerative processes are initiated earlier and that regeneration overall is more efficient in younger fish. PMID:26121607

  8. Highlighting short-lived excited electronic states with pump-degenerate-four-wave-mixing.

    PubMed

    Marek, Marie S; Buckup, Tiago; Southall, June; Cogdell, Richard J; Motzkus, Marcus

    2013-08-21

    Detection of short-lived transient species is a major challenge in femtosecond spectroscopy, especially when third-order techniques like transient absorption are used. Higher order methods employ additional interactions between light and matter to highlight such transient species. In this work we address numerically and experimentally the detection of ultrafast species with pump-Degenerate Four Wave Mixing (pump-DFWM). In this respect, conclusive identification of ultrafast species requires the proper determination of time-zero between all four laser pulses (pump pulse and the DFWM sequence). This is addressed here under the light of experimental parameters as well as molecular properties: The role of pulse durations, amount of pulse chirp as well as excited state life time is investigated by measuring a row of natural pigments differing mainly in the number of conjugated double bonds (N = 9 to 13). A comparison of the different signals reveals a strikingly unusual behavior of spheroidene (N = 10). Complete analysis of the pump-DFWM signal illustrates the power of the method and clearly assigns the uniqueness of spheroidene to a mixing of the initially excited state with a dark excited electronic state.

  9. Multiple, short-lived ``stellar prominences'' on O stars: the supergiant λ Cephei

    NASA Astrophysics Data System (ADS)

    Henrichs, H. F.; Sudnik, N.

    2015-01-01

    Many OB stars show unexplained cyclical variability in their winds and in many optical lines, which are formed at the base of the wind. For these stars no dipolar magnetic fields have been detected. We propose that these cyclical variations are caused by the presence of multiple, transient, short-lived, corotating magnetic loops, which we call ``stellar prominences''. We present a simplified model representing these prominences as corotating spherical blobs and fit the rapid variability in the Heii λ4686 line of the O supergiant λ Cep for time-resolved spectra obtained in 1989. Our conclusions are: (1) From model fits we find that the life time of the prominences varies, and is between 2-7 h. (2) The adopted inclination angle is 68° with a rotation period of ~ 4.1 d (but not well constrained). (3) The contribution of non-radial pulsations is negligible (4) Similar behavior is observed in at least 4 other O stars. We propose that prominences are a common phenomenon among O stars.

  10. New use of global warming potentials to compare cumulative and short-lived climate pollutants

    NASA Astrophysics Data System (ADS)

    Allen, Myles R.; Fuglestvedt, Jan S.; Shine, Keith P.; Reisinger, Andy; Pierrehumbert, Raymond T.; Forster, Piers M.

    2016-08-01

    Parties to the United Nations Framework Convention on Climate Change (UNFCCC) have requested guidance on common greenhouse gas metrics in accounting for Nationally determined contributions (NDCs) to emission reductions. Metric choice can affect the relative emphasis placed on reductions of `cumulative climate pollutants' such as carbon dioxide versus `short-lived climate pollutants' (SLCPs), including methane and black carbon. Here we show that the widely used 100-year global warming potential (GWP100) effectively measures the relative impact of both cumulative pollutants and SLCPs on realized warming 20-40 years after the time of emission. If the overall goal of climate policy is to limit peak warming, GWP100 therefore overstates the importance of current SLCP emissions unless stringent and immediate reductions of all climate pollutants result in temperatures nearing their peak soon after mid-century, which may be necessary to limit warming to ``well below 2 °C'' (ref. ). The GWP100 can be used to approximately equate a one-off pulse emission of a cumulative pollutant and an indefinitely sustained change in the rate of emission of an SLCP. The climate implications of traditional CO2-equivalent targets are ambiguous unless contributions from cumulative pollutants and SLCPs are specified separately.

  11. Recovery of short-lived chemical species in a couette flow reactor

    SciTech Connect

    Ouyang, Q.; Swinney, H.L. ); Roux, J.C.; Kepper, P.; Boissonade, J. )

    1992-04-01

    This paper reports on a new technique for studying and recovering short-lived chemical intermediate species that has been developed using a Couette reactor, which is an open one-dimensional reaction-diffusion system. Reaction occurs in the annulus between concentric cylinders with the inner one rotating and the outer one at rest. Fresh reagents are in contact with the ends of the annulus, but there is no net axial flow. The axial transport arising from the hydrodynamic motion is effectively diffusive, but has a diffusion coefficient 3 to 5 order of magnitude larger than that of molecular diffusion. The oxidant (ClO{sub 2}{sup {minus}}) and reductant (I{sup {minus}}) of an autocatalytic reaction are fed at opposite ends of the reactor. The reactants diffuse toward each other and react, forming a steady, sharp chemical front and a stable spatial concentration band of unstable intermediate species (HOCl) in the front region. Unstable intermediate species are thus stabilized at a well-defined spatial position where they can be recovered and studied. The experiments and numerical simulations demonstrate that the faster the reaction rate, the stabler the chemical front and the more effective the recovery of unstable intermediate species.

  12. Simulating the impact of emissions of brominated very short lived substances on past stratospheric ozone trends

    NASA Astrophysics Data System (ADS)

    Sinnhuber, Björn-Martin; Meul, Stefanie

    2015-04-01

    Bromine from very short lived substances (VSLS), primarily from natural oceanic sources, contributes substantially to the stratospheric bromine loading. This source of stratospheric bromine has so far been ignored in most chemistry climate model calculations of stratospheric ozone trends. Here we present a transient simulation with the chemistry climate model EMAC for the period 1960-2005 including emissions of the five brominated VSLS CHBr3, CH2Br2, CH2BrCl, CHBrCl2, and CHBr2Cl. The emissions lead to a realistic stratospheric bromine loading of about 20 pptv for present-day conditions. Comparison with a standard model simulation without VSLS shows large differences in modeled ozone in the extratropical lowermost stratosphere and in the troposphere. Differences in ozone maximize in the Antarctic Ozone Hole, resulting in more than 20% less ozone when VSLS are included. Even though the emissions of VSLS are assumed to be constant in time, the model simulation with VSLS included shows a much larger ozone decrease in the lowermost stratosphere during the 1979-1995 period and a faster ozone increase during 1996-2005, in better agreement with observed ozone trends than the standard simulation without VSLS emissions.

  13. Dissolved organic matter composition drives the marine production of brominated very short-lived substances.

    PubMed

    Liu, Yina; Thornton, Daniel C O; Bianchi, Thomas S; Arnold, William A; Shields, Michael R; Chen, Jie; Yvon-Lewis, Shari A

    2015-03-17

    Brominated very short-lived substances (BrVSLS), such as bromoform, are important trace gases for stratospheric ozone chemistry. These naturally derived trace gases are formed via bromoperoxidase-mediated halogenation of dissolved organic matter (DOM) in seawater. Information on DOM type in relation to the observed BrVSLS concentrations in seawater, however, is scarce. We examined the sensitivity of BrVSLS production in relation to the presence of specific DOM moieties. A total of 28 model DOM compounds in artificial seawater were treated with vanadium bromoperoxidase (V-BrPO). Our results show a clear dependence of BrVSLS production on DOM type. In general, molecules that comprise a large fraction of the bulk DOM pool did not noticeably affect BrVSLS production. Only specific cell metabolites and humic acid appeared to significantly enhance BrVSLS production. Amino acids and lignin phenols suppressed enzyme-mediated BrVSLS production and may instead have formed halogenated nonvolatile molecules. Dibromomethane production was not observed in any experiments, suggesting it is not produced by the same pathway as the other BrVSLS. Our results suggest that regional differences in DOM composition may explain the observed BrVSLS concentration variability in the global ocean. Ultimately, BrVSLS production and concentrations are likely affected by DOM composition, reactivity, and cycling in the ocean. PMID:25723123

  14. Short-Lived Climate Forcers - The Connections Between Emissions, Forcing, and Mitigation Potential (Invited)

    NASA Astrophysics Data System (ADS)

    Smith, S.

    2010-12-01

    Methane, tropospheric ozone, and aerosols have a substantial global and regional influence on climate in addition to the impact of ozone and aerosols on health and ecosystems. These climate forcing agents are linked both though common emissions sources and atmospheric chemical processes. The magnitude and regional distribution of these forcings have changed substantially over the past and is expected to continue to change into the future. While aerosols have had a substantial impact on climate over the past century, by the end of the 21st century aerosols will likely be only a minor contributor to radiative forcing. Overall, reductions in aerosol emissions lead to a net warming due to the net negative aerosol forcing, although some mitigation benefits may be possible in specific sub-sectors. While the emissions leading to enhanced tropospheric ozone levels are short-lived, mitigation has proved to be difficult due to the ubiquity of major emission sources, particularly surface transportation vehicles. From a mitigation standpoint, therefore, tropospheric ozone might be considered as more of a long-term pollutant. This presentation will review these links using historical data and future projections and discuss the implications for mitigation. The implications of these links for atmospheric chemistry analysis, and the potential for using ACC-MIP results to improve integrated assessment modeling and analysis, will be discussed.

  15. Highly heterogeneous, activated and short-lived regulatory T cells during chronic filarial infection

    PubMed Central

    Metenou, Simon; Coulibaly, Yaya I.; Sturdevant, Daniel; Dolo, Housseini; Diallo, Abdallah A.; Soumaoro, Lamine; Coulibaly, Michel E.; Kanakabandi, Kishore; Porcella, Stephen F.; Klion, Amy D.; Nutman, Thomas B.

    2016-01-01

    The mechanisms underlying the increase in the numbers of regulatory T (Treg) cells in chronic infection settings remain unclear. Here we have delineated the phenotype and transcriptional profiles of Treg cells from 18 filarial-infected (Fil+) and 19 filarial-uninfected (Fil-) subjects. We found that the frequencies of Foxp3+ Treg cells expressing CTLA-4, GITR, LAG-3 and IL-10 were significantly higher in Fil+ subjects compared with that in Fil- subjects. Foxp3-expressing Treg-cell populations in Fil+ subjects were also more heterogeneous and had higher expression of IL-10, CCL-4, IL-29, CTLA-4 and TGF-β than Fil- subjects, each of these cytokines having been implicated in immune suppression. Moreover, Foxp3-expressing Treg cells from Fil+ subjects had markedly upregulated expression of activation-induced apoptotic genes with concomitant downregulation of those involved in cell survival. To determine whether the expression of apoptotic genes was due to Treg-cell activation, we found that the expression of CTLA-4, CDk8, RAD50, TNFRSF1A, FOXO3 and RHOA were significantly upregulated in stimulated cells compared with unstimulated cells. Taken together, our results suggest that in patent filarial infection, the expanded Treg-cell populations are heterogeneous, short-lived, activated and express higher levels of molecules known to modulate immune responsiveness, suggesting that filarial infection is associated with high Treg-cell turnover. PMID:24737144

  16. Spin relaxation of a short-lived radical in zero magnetic field.

    PubMed

    McKenzie, Iain

    2011-01-21

    A short-lived radical containing only one I = 1/2 nucleus, the muoniated 1,2-dicarboxyvinyl radical dianion, was produced in an aqueous solution by the reaction of muonium with the dicarboxyacetylene dianion. The identity of the radical was confirmed by measuring the muon hyperfine coupling constant (hfcc) by transverse field muon spin rotation spectroscopy and comparing this value with the hfcc obtained from DFT calculations. The muon spin relaxation rate of this radical was measured as a function of temperature in zero magnetic field by the zero field muon spin relaxation technique. The results have been interpreted using the theoretical model of Fedin et al. (J. Chem. Phys., 2003, 118, 192). The muon spin polarization decreases exponentially with time after muon implantation and the temperature dependence of the spin relaxation rate indicates that the dominant relaxation mechanism is the modulation of the anisotropic hyperfine interaction due to molecular rotation. The effective radius of the radical in solution was determined to be 1.12 ± 0.04 nm from the dependence of the muon spin relaxation rate on the temperature and viscosity of the solution, and is approximately 3.6 times larger than the value obtained from DFT calculations.

  17. Simulating Supernova Injection of Short Lived Radionuclides with Consideration of the Solar Birth Environment

    NASA Astrophysics Data System (ADS)

    Davis, Keith W.; Leising, M. D.

    2006-12-01

    The existence of short-lived radionuclides (SLRNs) in the early solar system above their background galactic abundances is well accepted. Studies into the relative abundances and possible sources for radioisotopes indicate a model with three separate sources for the total abundance of SLRNs: the background galactic value, material from some nearby stellar source, and in-situ creation by the early active Sun. A type II SN may be the most likely source for the stellar component, specifically 60Fe. The geometric details of the stellar birth are largely unknown despite evidence that the presolar cloud was not isolated. From a hydrodynamic perspective, the injection of SLRNs may be difficult because of intervening material between the core and the explosion necessary to slow the shock speed enough that the core is compressed rather than shredded. For the SN component it is vital to understand how SN ejecta can reach a core and whether certain SN/cloud environments are precluded by the hydrodynamics. We present Zeus-2D simulations studying the possibility of SLRN injection into a presolar core that is part of a larger cloud complex.

  18. Preliminary results on the production of short-lived radioisotopes with a Plasma Focus device.

    PubMed

    Angeli, E; Tartari, A; Frignani, M; Mostacci, D; Rocchi, F; Sumini, M

    2005-01-01

    An experimental campaign was conducted to assess the feasibility of short-lived radioisotope (SLR) production within the pulsed discharges of a Plasma Focus (PF) device. This so-called "endogenous production" technique rests on the exploitation of nuclear reactions for the creation of SLR directly within the plasma, rather than on irradiating an external target. Until now only one research group has published data relevant to PF endogenous production of SLR, and the data seem to confirm that the PF has the capability to breed SLR. The campaign demonstrated production of (15)O, (17)F and (13)N from the (14)N(d,n)(15)O, (12)C(d,n)(13)N and (16)O(d,n)(17)F reactions. A 7kJ, 17kV Mather-type PF was operated with natural nitrogen, oxygen, CO(2) and deuterium in the vacuum chamber. Results to date confirm that, with a PF of this type, up to 1microCi of SLRs per discharge can be obtained. PMID:15985375

  19. Comparing the climate effect of emissions of short- and long-lived climate agents.

    PubMed

    Shine, Keith P; Berntsen, Terje K; Fuglestvedt, Jan S; Skeie, Ragnhild Bieltvedt; Stuber, Nicola

    2007-07-15

    Multi-gas climate agreements require a metric by which emissions of gases with different lifetimes and radiative properties can be placed on a common scale. The Kyoto Protocol to the United Nations Framework Convention on Climate Change uses the global warming potential (GWP) as such a metric. The GWP has attracted particular criticism as being inappropriate in the context of climate policy which seeks to restrict warming below a given target, because it gives equal weight to emissions irrespective of the target and the proximity to the target. The use of an alternative metric, the time-dependent global temperature change potential (GTP), is examined for its suitability and the prospects for it including very short-lived species. It retains the transparency and relative ease of use, which are attractive features of the GWP, but explicitly includes a dependence on the target of climate policy. The weighting of emissions using the GTP is found to be significantly dependent on the scenarios of future emissions and the sensitivity of the climate system. This may indicate that the use of any GTP-based weighting in future policymaking would necessitate regular revisions, as the global-mean temperature moves towards a specified target.

  20. Development of a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers

    NASA Astrophysics Data System (ADS)

    Kiser, Matthew R.

    Over the past 200 years, the Earth's atmospheric carbon dioxide (CO 2) concentration has increased by more than 35%, and climate experts predict that CO2 levels may double by the end of this century. Understanding the mechanisms of resource management in plants is fundamental for predicting how plants will respond to the increase in atmospheric CO 2. Plant productivity sustains life on Earth and is a principal component of the planet's system that regulates atmospheric CO2 concentration. As such, one of the central goals of plant science is to understand the regulatory mechanisms of plant growth in a changing environment. Short-lived positron-emitting radiotracer techniques provide time-dependent data that are critical for developing models of metabolite transport and resource distribution in plants and their microenvironments. To better understand the effects of environmental changes on resource transport and allocation in plants, we have developed a system for real-time measurements of rnetabolite transport in plants using short-lived positron-emitting radio-tracers. This thesis project includes the design, construction, and demonstration of the capabilities of this system for performing real-time measurements of metabolite transport in plants. The short-lived radiotracer system described in this dissertation takes advantage of the combined capabilities and close proximity of two research facilities at. Duke University: the Triangle Universities Nuclear Laboratory (TUNL) and the Duke University Phytotron, which are separated by approximately 100 meters. The short-lived positron-emitting radioisotopes are generated using the 10-MV tandem Van de Graaff accelerator located in the main TUNL building, which provides the capability of producing short-lived positron-emitting isotopes such as carbon-11 (11C: 20 minute half-life), nitrogen-13 (13N; 10 minute half-life), fluorine-18 (18F; 110 minute half-life), and oxygen-15 (15O; 2 minute half-life). The radioisotopes may

  1. Detection of 210Po on filter papers 16 years after use for the collection of short-lived radon progeny in a room.

    PubMed

    Abu-Jarad, F; Fazal-ur-Rehman

    2003-01-01

    Radon gas was allowed to accumulate in its radium source and then injected into a 36 m(3) test room, resulting in an initial radon concentration of 15 kBq m(-3). Filter papers were used to collect the short-lived radon progeny and thus to measure the Potential Alpha Energy Concentration (PAEC) in-situ in the year 1984 at different times and conditions according to the experimental design. The radon progeny collected on the filter papers were studied as a function of aerosol particle concentration ranging from 10(2)-10(5) particles cm(-3) in three different experiments. The highest aerosol particle concentration was generated by indoor cigarette smoking. Those filters were stored after the experiment, and were used after 16 years to study the activity of the radon long-lived alpha emitter progeny, (210)Po (T(1/2)=138 days). This isotope is separated from the short-lived progeny by (210)Pb beta emitter with 22.3 years half-life. After 16 years' storage of these filters, each filter paper was sandwiched and wrapped between two CR-39 nuclear track detectors, to put the detectors in contact with the surfaces of different filters, for 337 days. Correlation between the PAEC measured using filter papers in the year 1984 and the activity of long-lived alpha emitter (210)Po on the same filter papers measured in the year 2000 were studied. The results of the (210)Po activity showed a very good correlation of 0.92 with the PAEC 16 years ago. The results also depict that the PAEC and (210)Po activity in indoor air increased with the increase of aerosol particle concentration, which shows the attachment of short-lived radon progeny with the aerosol particles. The experiment proves that indoor cigarette smoking is a major source of aerosol particles carrying radon progeny and, thus, indoor cigarette smoking is an additional source of internal radiation hazard to the occupants whether smoker or non-smoker.

  2. Sizes and shapes of short-lived nuclei via laser spectroscopy. Progress report, May 1, 1980-January 31, 1981

    SciTech Connect

    Lewis, D.A.

    1981-02-01

    The first stage of the program to study the sizes and shapes of short-lived nuclei through their atomic hyperfine structure is to develop a movable laser spectroscopy system. This system is now almost complete and is described in this report along with plans for measurements at Argonne National Laboratory and Brookhaven National Laboratory.

  3. A Proposal for Assessing Study Quality: Biomonitoring, Environmental Epidemiology, and Short-Lived Chemicals (BEES-C) Instrument

    EPA Science Inventory

    The quality of exposure assessment is a major determinant of the overall quality of any environmental epidemiology study. The use of biomonitoring as a tool for assessing exposure to ubiquitous chemicals with short physiologic half-lives began relatively recently. These chemicals...

  4. Vertical distribution and isotopic composition of living planktonic foraminifera in the western North Atlantic

    SciTech Connect

    Fairbanks, R.G.; Wiebe, P.H.; Be, A.W.H.

    1980-01-04

    Thirteen species of planktonic foraminifera collected with vertically stratified zooplankton tows in the slope water, Gulf Stream cold core ring, and northern Sargasso Sea show significant differences in their vertical distributions in the upper 200 meters of these different hydrographic regimes. Gulf Stream cold core rings may be responsible for a southern displacement of the faunal boundary associated with the Gulf Stream when reconstructed from the deep-sea sediment record. Oxygen isotope analyses of seven species reveal that nonspinose species (algal symbiont-barren) apparently calcify in oxygen isotope equilibrium, whereas spinose species usually calcify out of oxygen isotope equilibrium by approximately -0.3 to -0.4 per mil in delta/sup 18/O values. The isotope data indicate that foraminifera shells calcify in depth zones that are significantly narrower than the overall vertical distribution of a species would imply.

  5. Fast-Neutron Activation of Long-Lived Isotopes in Enriched Ge

    SciTech Connect

    Elliott, Steven R.; Guiseppe, Vincente; LaRoque, B. H.; Johnson, R. A.; Mashnik, Stephan G.

    2010-11-16

    We measured the production of 57Co, 54Mn, 68Ge, 65Zn, and 60Co in an sample of Ge enriched in isotope 76 due to high-energy neutron interactions. These isotopes are critical in understanding background in Ge detectors used for double-beta decay experiments. These isotopes are produced by cosmogenic-neutron interactions in the detectors while they reside on the Earth's surface. We compared the measured production to that predicted by cross-section calculations based on CEM03.02. The cross section calculations over-predict our measurements by approximately a factor of 2-3 depending on isotope. We then use the measured cosmic-ray neutron ux and our results to predict the cosmogenic production rate with an accuracy near 15%.

  6. Triggering collapse of the presolar dense cloud core and injecting short-lived radioisotopes with a shock wave. III. Rotating three-dimensional cloud cores

    SciTech Connect

    Boss, Alan P.; Keiser, Sandra A.

    2014-06-10

    A key test of the supernova triggering and injection hypothesis for the origin of the solar system's short-lived radioisotopes is to reproduce the inferred initial abundances of these isotopes. We present here the most detailed models to date of the shock wave triggering and injection process, where shock waves with varied properties strike fully three-dimensional, rotating, dense cloud cores. The models are calculated with the FLASH adaptive mesh hydrodynamics code. Three different outcomes can result: triggered collapse leading to fragmentation into a multiple protostar system; triggered collapse leading to a single protostar embedded in a protostellar disk; or failure to undergo dynamic collapse. Shock wave material is injected into the collapsing clouds through Rayleigh-Taylor fingers, resulting in initially inhomogeneous distributions in the protostars and protostellar disks. Cloud rotation about an axis aligned with the shock propagation direction does not increase the injection efficiency appreciably, as the shock parameters were chosen to be optimal for injection even in the absence of rotation. For a shock wave from a core-collapse supernova, the dilution factors for supernova material are in the range of ∼10{sup –4} to ∼3 × 10{sup –4}, in agreement with recent laboratory estimates of the required amount of dilution for {sup 60}Fe and {sup 26}Al. We conclude that a type II supernova remains as a promising candidate for synthesizing the solar system's short-lived radioisotopes shortly before their injection into the presolar cloud core by the supernova's remnant shock wave.

  7. "Short Courses Shouldn't Be Short-Lived!" Enhancing Longer-Term Impact of Short English as a Foreign Language INSET Initiatives in China

    ERIC Educational Resources Information Center

    Yan, Chunmei; He, Chuanjun

    2015-01-01

    Short in-service teacher development (INSET) programmes have been globally used as a form of teacher development, but their impact has been under question. This study sought to examine teacher participants' perceptions of short INSET programmes to come up with better solutions to enhancing their effect on teachers' professional learning. A…

  8. Convective transport of very-short-lived bromocarbons to the stratosphere

    NASA Astrophysics Data System (ADS)

    Liang, Q.; Atlas, E.; Blake, D.; Dorf, M.; Pfeilsticker, K.; Schauffler, S.

    2014-01-01

    We use the NASA GEOS Chemistry Climate Model (GEOSCCM) to quantify the contribution of two most important brominated very short-lived substances (VSLS), bromoform (CHBr3) and dibromomethane (CH2Br2), to stratospheric bromine and its sensitivity to convection strength. Model simulations suggest that the most active transport of VSLS from the marine boundary layer through the tropopause occurs over the tropical Indian Ocean, the Western Pacific warm pool, and off the Pacific coast of Mexico. Together, convective lofting of CHBr3 and CH2Br2 and their degradation products supplies ∼8 ppt total bromine to the base of the Tropical Tropopause Layer (TTL, ∼150 hPa), similar to the amount of VSLS organic bromine available in the marine boundary layer (∼7.8-8.4 ppt) in the above active convective lofting regions. Of the total ∼8 ppt VSLS-originated bromine that enters the base of TTL at ∼150 hPa, half is in the form of source gas injection (SGI) and half as product gas injection (PGI). Only a small portion (< 10%) the VSLS-originated bromine is removed via wet scavenging in the TTL before reaching the lower stratosphere. On global and annual average, CHBr3 and CH2Br2, together, contribute ∼7.7 pptv to the present-day inorganic bromine in the stratosphere. However, varying model deep convection strength between maximum and minimum convection conditions can introduce a ∼2.6 pptv uncertainty in the contribution of VSLS to inorganic bromine in the stratosphere (BryVSLS). Contrary to the conventional wisdom, minimum convection condition leads to a larger BryVSLS as the reduced scavenging in soluble product gases, thus a significant increase in PGI (2-3 ppt), greatly exceeds the relative minor decrease in SGI (a few 10ths ppt).

  9. Convective Transport of Very-short-lived Bromocarbons to the Stratosphere

    NASA Technical Reports Server (NTRS)

    Liang, Qing; Atlas, Elliot Leonard; Blake, Donald Ray; Dorf, Marcel; Pfeilsticker, Klaus August; Schauffler, Sue Myhre

    2014-01-01

    We use the NASA GEOS Chemistry Climate Model (GEOSCCM) to quantify the contribution of two most important brominated very short-lived substances (VSLS), bromoform (CHBr3) and dibromomethane (CH2Br2), to stratospheric bromine and its sensitivity to convection strength. Model simulations suggest that the most active transport of VSLS from the marine boundary layer through the tropopause occurs over the tropical Indian Ocean, the Western Pacific warm pool, and off the Pacific coast of Mexico. Together, convective lofting of CHBr3 and CH2Br2 and their degradation products supplies 8 ppt total bromine to the base of the Tropical Tropopause Layer (TTL, 150 hPa), similar to the amount of VSLS organic bromine available in the marine boundary layer (7.8-8.4 ppt) in the above active convective lofting regions. Of the total 8 ppt VSLS-originated bromine that enters the base of TTL at 150 hPa, half is in the form of source gas injection (SGI) and half as product gas injection (PGI). Only a small portion (< 10%) the VSLS-originated bromine is removed via wet scavenging in the TTL before reaching the lower stratosphere. On global and annual average, CHBr3 and CH2Br2, together, contribute 7.7 pptv to the present-day inorganic bromine in the stratosphere. However, varying model deep convection strength between maximum and minimum convection conditions can introduce a 2.6 pptv uncertainty in the contribution of VSLS to inorganic bromine in the stratosphere (BryVSLS). Contrary to the conventional wisdom, minimum convection condition leads to a larger BryVSLS as the reduced scavenging in soluble product gases, thus a significant increase in PGI (2-3 ppt), greatly exceeds the relative minor decrease in SGI (a few 10ths ppt.

  10. Climate responses to anthropogenic emissions of short-lived climate pollutants

    NASA Astrophysics Data System (ADS)

    Baker, L. H.; Collins, W. J.; Olivié, D. J. L.; Cherian, R.; Hodnebrog, Ø.; Myhre, G.; Quaas, J.; Samset, B. H.

    2015-02-01

    Policies to control air quality focus on mitigating emissions of aerosols and their precursors, and other short-lived climate pollutants (SLCPs). On a local scale, these policies will have beneficial impacts on health and crop yields, by reducing particulate matter (PM) and surface ozone concentrations; however, the climate impacts of reducing emissions of SLCPs are less straightforward to predict. In this paper we consider a set of idealised, extreme mitigation strategies, in which the total anthropogenic emissions of individual SLCP emissions species are removed. This provides an upper bound on the potential climate impacts of such air quality strategies. We focus on evaluating the climate responses to changes in anthropogenic emissions of aerosol precursor species: black carbon (BC), organic carbon (OC) and sulphur dioxide (SO2). We perform climate integrations with four fully coupled atmosphere-ocean global climate models (AOGCMs), and examine the effects on global and regional climate of removing the total land-based anthropogenic emissions of each of the three aerosol precursor species. We find that the SO2 emissions reductions lead to the strongest response, with all three models showing an increase in surface temperature focussed in the northern hemisphere high latitudes, and a corresponding increase in global mean precipitation and run-off. Changes in precipitation and run-off patterns are driven mostly by a northward shift in the ITCZ, consistent with the hemispherically asymmetric warming pattern driven by the emissions changes. The BC and OC emissions reductions give a much weaker forcing signal, and there is some disagreement between models in the sign of the climate responses to these perturbations. These differences between models are due largely to natural variability in sea-ice extent, circulation patterns and cloud changes. This large natural variability component to the signal when the ocean circulation and sea-ice are free-running means that the

  11. Climate responses to anthropogenic emissions of short-lived climate pollutants

    NASA Astrophysics Data System (ADS)

    Baker, L. H.; Collins, W. J.; Olivié, D. J. L.; Cherian, R.; Hodnebrog, Ø.; Myhre, G.; Quaas, J.

    2015-07-01

    Policies to control air quality focus on mitigating emissions of aerosols and their precursors, and other short-lived climate pollutants (SLCPs). On a local scale, these policies will have beneficial impacts on health and crop yields, by reducing particulate matter (PM) and surface ozone concentrations; however, the climate impacts of reducing emissions of SLCPs are less straightforward to predict. In this paper we consider a set of idealized, extreme mitigation strategies, in which the total anthropogenic emissions of individual SLCP emissions species are removed. This provides an upper bound on the potential climate impacts of such air quality strategies. We focus on evaluating the climate responses to changes in anthropogenic emissions of aerosol precursor species: black carbon (BC), organic carbon (OC) and sulphur dioxide (SO2). We perform climate integrations with four fully coupled atmosphere-ocean global climate models (AOGCMs), and examine the effects on global and regional climate of removing the total land-based anthropogenic emissions of each of the three aerosol precursor species. We find that the SO2 emissions reductions lead to the strongest response, with all models showing an increase in surface temperature focussed in the Northern Hemisphere mid and (especially) high latitudes, and showing a corresponding increase in global mean precipitation. Changes in precipitation patterns are driven mostly by a northward shift in the ITCZ (Intertropical Convergence Zone), consistent with the hemispherically asymmetric warming pattern driven by the emissions changes. The BC and OC emissions reductions give a much weaker response, and there is some disagreement between models in the sign of the climate responses to these perturbations. These differences between models are due largely to natural variability in sea-ice extent, circulation patterns and cloud changes. This large natural variability component to the signal when the ocean circulation and sea-ice are

  12. Response of Arctic Temperature to Changes in Emissions of Short-Lived Climate Forcers

    NASA Astrophysics Data System (ADS)

    Sand, M.; Berntsen, T.; von Salzen, K.; Flanner, M.; Langner, J.; Victor, D. G.

    2015-12-01

    There is growing scientific and political interest in the impacts of climate change and anthropogenic emissions on the Arctic. Over recent decades temperatures in the Arctic have increased twice the global rate, largely due to ice albedo and temperature feedbacks. While deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short lived climate forcers (SLCFs). Politically, action on SLCFs may be particularly promising because the benefits of mitigation appear promptly and there are large co-benefits in terms of improved air quality. This study is the first to systematically quantify the Arctic climate impact of regional SLCF emissions, taking into account BC, sulphur dioxide (SO2), nitrogen oxides (NOx), volatile hydrocarbons (VOC), organic carbon (OC) and tropospheric ozone, their transport processes and transformations in the atmosphere. Using several chemical transport models we perform detailed radiative forcing calculations from emissions of these species. Geographically we separate emissions into seven source regions that correspond with the national groupings of the Arctic Council, the leading body organizing international policy in the region (the United States, Canada, the Nordic countries, the rest of Europe, Russia, East and South Asia, and the rest of the world). We look at six main sectors known to account for [nearly all] of these emissions: households (domestic), energy/industry/waste, transport, agricultural fires, grass/forest fires, and gas flaring. We find that the largest Arctic warming source is from emissions within the Asian nations. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. A stringent, but technically feasible SLCFs mitigation scenario, phased in from 2015 through 2030, can cut warming by 0.2 K in 2050.

  13. Response of Arctic temperature to changes in emissions of short-lived climate forcers

    NASA Astrophysics Data System (ADS)

    Sand, M.; Berntsen, T. K.; von Salzen, K.; Flanner, M. G.; Langner, J.; Victor, D. G.

    2016-03-01

    There is growing scientific and political interest in the impacts of climate change and anthropogenic emissions on the Arctic. Over recent decades temperatures in the Arctic have increased at twice the global rate, largely as a result of ice-albedo and temperature feedbacks. Although deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short-lived climate forcers (SLCFs; refs ,). Politically, action on SLCFs may be particularly promising because the benefits of mitigation are seen more quickly than for mitigation of CO2 and there are large co-benefits in terms of improved air quality. This Letter is one of the first to systematically quantify the Arctic climate impact of regional SLCFs emissions, taking into account black carbon (BC), sulphur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs), organic carbon (OC) and tropospheric ozone (O3), and their transport processes and transformations in the atmosphere. This study extends the scope of previous works by including more detailed calculations of Arctic radiative forcing and quantifying the Arctic temperature response. We find that the largest Arctic warming source is from emissions within the Asian nations owing to the large absolute amount of emissions. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. A stringent, but technically feasible mitigation scenario for SLCFs, phased in from 2015 to 2030, could cut warming by 0.2 (+/-0.17) K in 2050.

  14. Name Modelling Activities for the CAST/Contrast/Attrex Very Short Lived Species Measurements

    NASA Astrophysics Data System (ADS)

    Harris, N. R. P.; Filus, M. T.; Ashfold, M.; Pyle, J. A.; Atlas, E. L.; Manning, A.; Meneguz, E.

    2014-12-01

    The UK Met Office Numerical Atmospheric dispersion Modeling Environment (NAME) is used to assess the spatial and temporal variability of transport of very short-lived halogenated organic species (VSLS), in particular bromoform, dibromomethane and methyl iodide, within the West Pacific tropical region. The NAME modelling results are compared with airborne measurements of VSLS taken during NASA ATTREX, NCAR CONTRAST and NERC CAST campaigns in January-March, 2014. In this work, the NAME model is used to link the aircraft measurements to examine the vertical distribution of VSLS in the West Pacific troposphere. The major focus will be on assessing vertical transport in deep convection which is one of the crucial factors in redistributing chemicals within the tropical troposphere. The work presented shows the analysis of NAME runs made from the ATTREX flights over the East Pacific in January-February, 2013 and the ATTREX and CONTRAST flight tracks over the West Pacific in January-March, 2014. Each ATTREX 2013 and 2014 flight track is divided into segments, from which particles are released and followed backward to identify the low-level sources of air. Particles (10,000 per single point along the flight track) are released from the flight tracks and followed 12-days backwards. Fractions of trajectories are calculated according to particles which crossed below 5 and 1 km (corresponding to low troposphere and oceanic boundary layer, respectively). Then, initial concentrations for VSLS are assigned to particles which originated from below 5/1 km and final concentrations at flight altitudes are determined based on e-folding equations. Results, obtained by running NAME, are compared with ATTREX VSLS flight measurements.

  15. Response of Arctic Temperature to Changes in Emissions of Short-Lived Climate Forcers

    NASA Astrophysics Data System (ADS)

    Sand, M.; Berntsen, T.; von Salzen, K.; Flanner, M.; Langner, J.; Victor, D. G.

    2014-12-01

    There is growing scientific and political interest in the impacts of climate change and anthropogenic emissions on the Arctic. Over recent decades temperatures in the Arctic have increased twice the global rate, largely due to ice albedo and temperature feedbacks. While deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short lived climate forcers (SLCFs). Politically, action on SLCFs may be particularly promising because the benefits of mitigation appear promptly and there are large co-benefits in terms of improved air quality. This study is the first to systematically quantify the Arctic climate impact of regional SLCF emissions, taking into account BC, sulphur dioxide (SO2), nitrogen oxides (NOx), volatile hydrocarbons (VOC), organic carbon (OC) and tropospheric ozone, their transport processes and transformations in the atmosphere. Using several chemical transport models we perform detailed radiative forcing calculations from emissions of these species. Geographically we separate emissions into seven source regions that correspond with the national groupings of the Arctic Council, the leading body organizing international policy in the region (the United States, Canada, the Nordic countries, the rest of Europe, Russia, East and South Asia, and the rest of the world). We look at six main sectors known to account for [nearly all] of these emissions: households (domestic), energy/industry/waste, transport, agricultural fires, grass/forest fires, and gas flaring. We find that the largest Arctic warming source is from emissions within the Asian nations. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. A stringent, but technically feasible SLCFs mitigation scenario, phased in from 2015 through 2030, can cut warming by 0.2 K in 2050.

  16. Recent activities for β-decay half-lives and β-delayed neutron emission of very neutron-rich isotopes

    SciTech Connect

    Dillmann, Iris; Abriola, Daniel; Singh, Balraj

    2014-05-02

    Beta-delayed neutron (βn) emitters play an important, two-fold role in the stellar nucleosynthesis of heavy elements in the 'rapid neutron-capture process' (r process). On one hand they lead to a detour of the material β-decaying back to stability. On the other hand, the released neutrons increase the neutron-to-seed ratio, and are re-captured during the freeze-out phase and thus influence the final solar r-abundance curve. A large fraction of the isotopes inside the r-process reaction path are not yet experimentally accessible and are located in the (experimental) 'Terra Incognita'. With the next generation of fragmentation and ISOL facilities presently being built or already in operation, one of the main motivation of all projects is the investigation of these very neutron-rich isotopes. A short overview of one of the planned programs to measure βn-emitters at the limits of the presently know isotopes, the BRIKEN campaign (Beta delayed neutron emission measurements at RIKEN) will be given. Presently, about 600 β-delayed one-neutron emitters are accessible, but only for a third of them experimental data are available. Reaching more neutron-rich isotopes means also that multiple neutron-emission becomes the dominant decay mechanism. About 460 β-delayed two-, three-or four-neutron emitters are identified up to now but for only 30 of them experimental data about the neutron branching ratios are available, most of them in the light mass region below A=30. The International Atomic and Energy Agency (IAEA) has identified the urgency and picked up this topic recently in a 'Coordinated Research Project' on a 'Reference Database for Beta-Delayed Neutron Emission Data'. This project will review, compile, and evaluate the existing data for neutron-branching ratios and half-lives of β-delayed neutron emitters and help to ensure a reliable database for the future discoveries of new isotopes and help to constrain astrophysical and theoretical models.

  17. Increased Concentrations of Short-Lived Decay-Series Radionuclides in Groundwaters Underneath the Nopal I Uranium Deposit at Pena Blanca, Mexico

    NASA Astrophysics Data System (ADS)

    Luo, S.; Ku, T.; Todd, V.; Murrell, M. T.; Dinsmoor, J. C.

    2007-05-01

    The Nopal I uranium ore deposit at Pena Blanca, Mexico, located at > 200 meters above the groundwater table, provides an ideal natural analog for quantifying the effectiveness of geological barrier for isolation of radioactive waste nuclides from reaching the human environments through ground water transport. To fulfill such natural analog studies, three wells (PB1, PB2, and PB3 respectively) were drilled at the site from the land surface down to the saturated groundwater zone and ground waters were collected from each of these wells through large- volume sampling/in-situ Mn-filter filtration for analyses of short-lived uranium/thorium-series radionuclides. Our measurements from PB1 show that the groundwater standing in the hole has much lower 222Rn activity than the freshly pumped groundwater. From this change in 222Rn activity, we estimate the residence time of groundwater in PB1 to be about 20 days. Our measurements also show that the activities of short-lived radioisotopes of Th (234Th), Ra (228Ra, 224Ra, 223Ra), Rn (222Rn), Pb (210Pb), and Po (210Po) in PB1, PB2, and PB3 are all significantly higher than those from the other wells near the Nopal I site. These high activities provide evidence for the enrichment of long-lived U and Ra isotopes in the groundwater as well as in the associated adsorbed phases on the fractured aquifer rocks underneath the ore deposit. Such enrichment suggests a rapid dissolution of U and Ra isotopes from the uranium ore deposit in the vadose zone and the subsequent migration to the groundwater underneath. A reactive transport model can be established to characterize the in-situ transport of radionuclides at the site. The observed change of 222Rn activity at PB1 also suggests that the measured high radioactivityies in ground waters from the site isare not an artifact of drilling operations. However, further studies are needed to assess if or to what extent the radionuclide migration is affected by the previous mining activities at

  18. A LOWER INITIAL ABUNDANCE OF SHORT-LIVED {sup 41}Ca IN THE EARLY SOLAR SYSTEM AND ITS IMPLICATIONS FOR SOLAR SYSTEM FORMATION

    SciTech Connect

    Liu, Ming-Chang; Chaussidon, Marc; Srinivasan, Gopalan; McKeegan, Kevin D.

    2012-12-20

    The short-lived radionuclide {sup 41}Ca plays an important role in constraining the immediate astrophysical environment and the formation timescale of the nascent solar system due to its extremely short half-life (0.1 Myr). Nearly 20 years ago, the initial ratio of {sup 41}Ca/{sup 40}Ca in the solar system was determined to be (1.41 {+-} 0.14) Multiplication-Sign 10{sup -8}, primarily based on two Ca-Al-rich Inclusions (CAIs) from the CV chondrite Efremovka. With an advanced analytical technique for isotopic measurements, we reanalyzed the potassium isotopic compositions of the two Efremovka CAIs and inferred the initial ratios of {sup 41}Ca/{sup 40}Ca to be (2.6 {+-} 0.9) Multiplication-Sign 10{sup -9} and (1.4 {+-} 0.6) Multiplication-Sign 10{sup -9} (2{sigma}), a factor of 7-10 lower than the previously inferred value. Considering possible thermal processing that led to lower {sup 26}Al/{sup 27}Al ratios in the two CAIs, we propose that the true solar system initial value of {sup 41}Ca/{sup 40}Ca should have been {approx}4.2 Multiplication-Sign 10{sup -9}. Synchronicity could have existed between {sup 26}Al and {sup 41}Ca, indicating a uniform distribution of the two radionuclides at the time of CAI formation. The new initial {sup 41}Ca abundance is 4-16 times lower than the calculated value for steady-state galactic nucleosynthesis. Therefore, {sup 41}Ca could have originated as part of molecular cloud materials with a free decay time of 0.2-0.4 Myr. Alternative possibilities, such as a last-minute input from a stellar source and early solar system irradiation, could not be definitively ruled out. This underscores the need for more data from diverse CAIs to determine the true astrophysical origin of {sup 41}Ca.

  19. SU-C-204-07: The Production of Short-Lived Positron Emitters in Proton Therapy

    SciTech Connect

    Buitenhuis, H J T; Dendooven, P; Biegun, A K; Goethem, M-J van; Graaf, E R van der; Brandenburg, S; Diblen, F

    2015-06-15

    Purpose: To investigate the production and effect of short-lived positron emitters when using PET for in-vivo range verification during a proton therapy irradiation. Methods: The integrated production of short-lived positron emitters in the stopping of 55 MeV protons was measured in water, carbon, phosphorus and calcium targets. The experimental production rates are used to calculate the production on PMMA and a representative set of 4 tissue materials. The number of decays integrated over an irradiation in these materials is calculated as function of the duration of the irradiation, considering irradiations with the same total number of protons. Results: The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12-N (T1/2 = 11 ms) on carbon (9.5% of the 11-C production), 29-P (T1/2 = 4.1 s) on phosphorus (20% of the 30-P production) and 38m-K (T1/2 = 0.92 s) on calcium (113% of the 38g-K production). No short-lived nuclides are produced on water. The most noticeable Result is that for an irradiation in (carbon-rich) adipose tissue, 12-N will dominate the PET image up to an irradiation duration of 70 s. On bone tissue, 15-O dominates over 12-N after 7–15 s (depending on the carbon-to-oxygen ratio). Conclusions: The presence of 12-N needs to be considered in PET imaging during proton beam irradiations as, depending on tissue composition and PET scanning protocol, it may noticeably deteriorate image quality due to the large positron range blurring. The results presented warrant investigations into the energy-dependent production of 12-N, 29-P and 38m-K and their effect on PET imaging during proton irradiations.

  20. Evaluating the climate and air quality impacts of short-lived pollutants

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Aamaas, B.; Amann, M.; Baker, L. H.; Bellouin, N.; Berntsen, T. K.; Boucher, O.; Cherian, R.; Collins, W.; Daskalakis, N.; Dusinska, M.; Eckhardt, S.; Fuglestvedt, J. S.; Harju, M.; Heyes, C.; Hodnebrog, Ø.; Hao, J.; Im, U.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Law, K. S.; Lund, M. T.; Maas, R.; MacIntosh, C. R.; Myhre, G.; Myriokefalitakis, S.; Olivié, D.; Quaas, J.; Quennehen, B.; Raut, J.-C.; Rumbold, S. T.; Samset, B. H.; Schulz, M.; Seland, Ø.; Shine, K. P.; Skeie, R. B.; Wang, S.; Yttri, K. E.; Zhu, T.

    2015-06-01

    This paper presents a summary of the work done within the European Union's Seventh Framework Programme project ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants). ECLIPSE had a unique systematic concept for designing a realistic and effective mitigation scenario for short-lived climate pollutants (SLCPs: methane, aerosols and ozone, and their precursor species) and quantifying its climate and air quality impacts, and this paper presents the results in the context of this overarching strategy. The first step in ECLIPSE was to create a new emission inventory based on current legislation (CLE) for the recent past and until 2050. Substantial progress compared to previous work was made by including previously unaccounted types of sources such as flaring of gas associated with oil production, and wick lamps. These emission data were used for present-day reference simulations with four advanced Earth system models (ESMs) and six chemistry transport models (CTMs). The model simulations were compared with a variety of ground-based and satellite observational data sets from Asia, Europe and the Arctic. It was found that the models still underestimate the measured seasonality of aerosols in the Arctic but to a lesser extent than in previous studies. Problems likely related to the emissions were identified for Northern Russia and India, in particular. To estimate the climate impacts of SLCPs, ECLIPSE followed two paths of research: the first path calculated radiative forcing (RF) values for a large matrix of SLCP species emissions, for different seasons and regions independently. Based on these RF calculations, the Global Temperature change Potential metric for a time horizon of 20 years (GTP20) was calculated for each SLCP emission type. This climate metric was then used in an integrated assessment model to identify all emission mitigation measures with a beneficial air quality and short-term (20 year) climate impact. These measures together

  1. Evaluating the climate and air quality impacts of short-lived pollutants

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Aamaas, B.; Amann, M.; Baker, L. H.; Bellouin, N.; Berntsen, T. K.; Boucher, O.; Cherian, R.; Collins, W.; Daskalakis, N.; Dusinska, M.; Eckhardt, S.; Fuglestvedt, J. S.; Harju, M.; Heyes, C.; Hodnebrog, Ø.; Hao, J.; Im, U.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Law, K. S.; Lund, M. T.; Maas, R.; MacIntosh, C. R.; Myhre, G.; Myriokefalitakis, S.; Olivié, D.; Quaas, J.; Quennehen, B.; Raut, J.-C.; Rumbold, S. T.; Samset, B. H.; Schulz, M.; Seland, Ø.; Shine, K. P.; Skeie, R. B.; Wang, S.; Yttri, K. E.; Zhu, T.

    2015-09-01

    This paper presents a summary of the work done within the European Union's Seventh Framework Programme project ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants). ECLIPSE had a unique systematic concept for designing a realistic and effective mitigation scenario for short-lived climate pollutants (SLCPs; methane, aerosols and ozone, and their precursor species) and quantifying its climate and air quality impacts, and this paper presents the results in the context of this overarching strategy. The first step in ECLIPSE was to create a new emission inventory based on current legislation (CLE) for the recent past and until 2050. Substantial progress compared to previous work was made by including previously unaccounted types of sources such as flaring of gas associated with oil production, and wick lamps. These emission data were used for present-day reference simulations with four advanced Earth system models (ESMs) and six chemistry transport models (CTMs). The model simulations were compared with a variety of ground-based and satellite observational data sets from Asia, Europe and the Arctic. It was found that the models still underestimate the measured seasonality of aerosols in the Arctic but to a lesser extent than in previous studies. Problems likely related to the emissions were identified for northern Russia and India, in particular. To estimate the climate impacts of SLCPs, ECLIPSE followed two paths of research: the first path calculated radiative forcing (RF) values for a large matrix of SLCP species emissions, for different seasons and regions independently. Based on these RF calculations, the Global Temperature change Potential metric for a time horizon of 20 years (GTP20) was calculated for each SLCP emission type. This climate metric was then used in an integrated assessment model to identify all emission mitigation measures with a beneficial air quality and short-term (20-year) climate impact. These measures together

  2. Evaluating the climate and air quality impacts of short-lived pollutants

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Aamaas, B.; Amann, M.; Baker, L. H.; Bellouin, N.; Berntsen, T. K.; Boucher, O.; Cherian, R.; Collins, W.; Daskalakis, N.; Dusinska, M.; Eckhardt, S.; Fuglestvedt, J. S.; Harju, M.; Heyes, C.; Hodnebrog, Ø.; Hao, J.; Im, U.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Law, K. S.; Lund, M. T.; Maas, R.; MacIntosh, C. R.; Myhre, G.; Myriokefalitakis, S.; Olivié, D.; Quaas, J.; Quennehen, B.; Raut, J.-C.; Rumbold, S. T.; Samset, B. H.; Schulz, M.; Seland, Ø.; Shine, K. P.; Skeie, R. B.; Wang, S.; Yttri, K. E.; Zhu, T.

    2015-09-01

    This paper presents a summary of the work done within the European Union's Seventh Framework Programme project ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants). ECLIPSE had a unique systematic concept for designing a realistic and effective mitigation scenario for short-lived climate pollutants (SLCPs; methane, aerosols and ozone, and their precursor species) and quantifying its climate and air quality impacts, and this paper presents the results in the context of this overarching strategy. The first step in ECLIPSE was to create a new emission inventory based on current legislation (CLE) for the recent past and until 2050. Substantial progress compared to previous work was made by including previously unaccounted types of sources such as flaring of gas associated with oil production, and wick lamps. These emission data were used for present-day reference simulations with four advanced Earth system models (ESMs) and six chemistry transport models (CTMs). The model simulations were compared with a variety of ground-based and satellite observational data sets from Asia, Europe and the Arctic. It was found that the models still underestimate the measured seasonality of aerosols in the Arctic but to a lesser extent than in previous studies. Problems likely related to the emissions were identified for northern Russia and India, in particular. To estimate the climate impacts of SLCPs, ECLIPSE followed two paths of research: the first path calculated radiative forcing (RF) values for a large matrix of SLCP species emissions, for different seasons and regions independently. Based on these RF calculations, the Global Temperature change Potential metric for a time horizon of 20 years (GTP20) was calculated for each SLCP emission type. This climate metric was then used in an integrated assessment model to identify all emission mitigation measures with a beneficial air quality and short-term (20-year) climate impact. These measures together

  3. Evaluating the climate and air quality impacts of short-lived pollutants

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Aamaas, B.; Amann, M.; Baker, L. H.; Bellouin, N.; Berntsen, T. K.; Boucher, O.; Cherian, R.; Collins, W.; Daskalakis, N.; Dusinska, M.; Eckhardt, S.; Fuglestvedt, J. S.; Harju, M.; Heyes, C.; Hodnebrog, Ø.; Hao, J.; Im, U.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Law, K. S.; Lund, M. T.; Maas, R.; MacIntosh, C. R.; Myhre, G.; Myriokefalitakis, S.; Olivié, D.; Quaas, J.; Quennehen, B.; Raut, J.-C.; Rumbold, S. T.; Samset, B. H.; Schulz, M.; Seland, Ø.; Shine, K. P.; Skeie, R. B.; Wang, S.; Yttri, K. E.; Zhu, T.

    2015-06-01

    This paper presents a summary of the work done within the European Union's Seventh Framework Programme project ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants). ECLIPSE had a unique systematic concept for designing a realistic and effective mitigation scenario for short-lived climate pollutants (SLCPs: methane, aerosols and ozone, and their precursor species) and quantifying its climate and air quality impacts, and this paper presents the results in the context of this overarching strategy. The first step in ECLIPSE was to create a new emission inventory based on current legislation (CLE) for the recent past and until 2050. Substantial progress compared to previous work was made by including previously unaccounted types of sources such as flaring of gas associated with oil production, and wick lamps. These emission data were used for present-day reference simulations with four advanced Earth system models (ESMs) and six chemistry transport models (CTMs). The model simulations were compared with a variety of ground-based and satellite observational data sets from Asia, Europe and the Arctic. It was found that the models still underestimate the measured seasonality of aerosols in the Arctic but to a lesser extent than in previous studies. Problems likely related to the emissions were identified for Northern Russia and India, in particular. To estimate the climate impacts of SLCPs, ECLIPSE followed two paths of research: the first path calculated radiative forcing (RF) values for a large matrix of SLCP species emissions, for different seasons and regions independently. Based on these RF calculations, the Global Temperature change Potential metric for a time horizon of 20 years (GTP20) was calculated for each SLCP emission type. This climate metric was then used in an integrated assessment model to identify all emission mitigation measures with a beneficial air quality and short-term (20 year) climate impact. These measures together

  4. Short-lived mammals (shrew, mouse) have a less robust metal-responsive transcription factor than humans and bats.

    PubMed

    Schmidt, Katharina; Steiner, Kurt; Petrov, Boyan; Georgiev, Oleg; Schaffner, Walter

    2016-06-01

    Non-essential "heavy" metals such as cadmium tend to accumulate in an organism and thus are a particular threat for long-lived animals. Here we show that two unrelated, short-lived groups of mammals (rodents and shrews, separated by 100 Mio years of evolution) each have independently acquired mutations in their metal-responsive transcription factor (MTF-1) in a domain relevant for robust transcriptional induction by zinc and cadmium. While key amino acids are mutated in rodents, in shrews an entire exon is skipped. Rodents and especially shrews are unique regarding the alterations of this region. To investigate the biological relevance of these alterations, MTF-1s from the common shrew (Sorex araneus), the mouse, humans and a bat (Myotis blythii), were tested by cotransfection with a reporter gene into cells lacking MTF-1. Whereas shrews only live for 1.5-2.5 years, bats, although living on a very similar insect diet, have a lifespan of several decades. We find that bat MTF-1 is similarly metal-responsive as its human counterpart, while shrew MTF-1 is less responsive, similar to mouse MTF-1. We propose that in comparison to most other mammals, the short-lived shrews and rodents can afford a "lower-quality" system for heavy metal homeostasis and detoxification. PMID:27067444

  5. Global Modeling and Projection of Short-Lived Climate Pollutants in an Earth System Model

    NASA Astrophysics Data System (ADS)

    Sudo, K.; Takemura, T.; Klimont, Z.; Kurokawa, J.; Akimoto, H.

    2013-12-01

    In predicting and mitigating future global warming, short-lived climate pollutants (SLCPs) such as tropospheric ozone (O3), black carbon (BC), and other related components including CH4/VOCs and aerosols play crucial roles as well as long-lived species like CO2 or N2O. Several recent studies suggests that reduction of heating SLCPs (i.e., O3 and black carbon) together with CH4 can decrease and delay the expected future warming, and can be an alternative to CO2 mitigation (Shindell et al., 2012). However it should be noted that there are still large uncertainties in simulating SLCPs and their climate impacts. For instance, present global models generally have a severe tendency to underestimate BC especially in remote areas like the polar regions as shown by the recent model intercomparison project under the IPCC (ACCMIP/AeroCOM). This problem in global BC modeling, basically coming from aging and removal processes of BC, causes still a large uncertainty in the estimate of BC's atmospheric heating and climate impacts (Bond et al., 2013; Kerr et al., 2013). This study attempted to improve global simulation of BC by developing a new scheme for simulating aging process of BC and re-evaluate radiative forcing of BC in the framework of a chemistry-aerosol coupled climate model (Earth system model) MIROC-ESM-CHEM. Our improved model with the new aging scheme appears to relatively well reproduce the observed BC concentrations and seasonality in the Arctic/Antarctic region. The new model estimates radiative forcing of BC to be 0.83 W m-2 which is about two times larger than the estimate by our original model with no aging scheme (0.41 W m-2), or the model ensemble mean in the IPCC report. Using this model, future projection of SLCPs and their climate impacts is conducted following the recent IIASA emission scenarios for the year 2030 (Klimont et al., 2006; Cofala et al., 2007). Our simulation suggests that heating SLCPs components (O3, BC, and CH4) are significantly reduced

  6. Distributions of short-lived radioactive nuclei produced by young embedded star clusters

    SciTech Connect

    Adams, Fred C.; Fatuzzo, Marco; Holden, Lisa

    2014-07-01

    Most star formation in the Galaxy takes place in clusters, where the most massive members can affect the properties of other constituent solar systems. This paper considers how clusters influence star formation and forming planetary systems through nuclear enrichment from supernova explosions, where massive stars deliver short-lived radioactive nuclei (SLRs) to their local environment. The decay of these nuclei leads to both heating and ionization, and thereby affects disk evolution, disk chemistry, and the accompanying process of planet formation. Nuclear enrichment can take place on two spatial scales: (1) within the cluster itself (ℓ ∼ 1 pc), the SLRs are delivered to the circumstellar disks associated with other cluster members. (2) On the next larger scale (ℓ ∼ 2-10 pc), SLRs are injected into the background molecular cloud; these nuclei provide heating and ionization to nearby star-forming regions and to the next generation of disks. For the first scenario, we construct the expected distributions of radioactive enrichment levels provided by embedded clusters. Clusters can account for the SLR mass fractions inferred for the early Solar Nebula, but typical SLR abundances are lower by a factor of ∼10. For the second scenario, we find that distributed enrichment of SLRs in molecular clouds leads to comparable abundances. For both the direct and distributed enrichment processes, the masses of {sup 26}Al and {sup 60}Fe delivered to individual circumstellar disks typically fall in the range 10-100 pM {sub ☉} (where 1 pM {sub ☉} = 10{sup –12} M {sub ☉}). The corresponding ionization rate due to SLRs typically falls in the range ζ{sub SLR} ∼ 1-5 × 10{sup –19} s{sup –1}. This ionization rate is smaller than that due to cosmic rays, ζ{sub CR} ∼ 10{sup –17} s{sup –1}, but will be important in regions where cosmic rays are attenuated (e.g., disk mid-planes).

  7. Multimodel emission metrics for regional emissions of short lived climate forcers

    NASA Astrophysics Data System (ADS)

    Aamaas, B.; Berntsen, T. K.; Fuglestvedt, J. S.; Shine, K. P.; Bellouin, N.

    2015-09-01

    For short lived climate forcers (SLCFs), the impact of emissions depends on where and when the emissions take place. Comprehensive new calculations of various emission metrics for SLCFs are presented based on radiative forcing (RF) values calculated in four different (chemistry-transport or coupled-chemistry climate) models. We distinguish between emissions during summer (May-October) and winter season (November-April) for emissions from Europe, East Asia, as well as the global shipping sector. The species included in this study are aerosols and aerosols precursors (BC, OC, SO2, NH3), and ozone precursors (NOx, CO, VOC), which also influence aerosols, to a lesser degree. Emission metrics for global climate responses of these emissions, as well as for CH4, have been calculated relative to CO2, using Global Warming Potential (GWP) and Global Temperature change Potential (GTP), based on dedicated RF simulations by four global models. The emission metrics include indirect cloud effects of aerosols and the semi-direct forcing for BC. In addition to the standard emission metrics for pulse and sustained emissions, we have also calculated a new emission metric designed for an emission profile consisting of a ramp up period of 15 years followed by sustained emissions, which is more appropriate for a gradual implementation of mitigation policies. For the aerosols, the emission metric values are larger in magnitude for Europe than East Asia and for summer than winter. A variation is also observed for the ozone precursors, with largest values in East Asia and winter for CO and in Europe and summer for VOC. In general, the variations between the emission metrics derived from different models are larger than the variations between regions and seasons, but the regional and seasonal variations for the best estimate also hold for most of the models individually. Further, the estimated climate impact of a mitigation policy package is robust even when accounting for correlations. For

  8. Regional emission metrics for short-lived climate forcers from multiple models

    NASA Astrophysics Data System (ADS)

    Aamaas, Borgar; Berntsen, Terje K.; Fuglestvedt, Jan S.; Shine, Keith P.; Bellouin, Nicolas

    2016-06-01

    For short-lived climate forcers (SLCFs), the impact of emissions depends on where and when the emissions take place. Comprehensive new calculations of various emission metrics for SLCFs are presented based on radiative forcing (RF) values calculated in four different (chemical-transport or coupled chemistry-climate) models. We distinguish between emissions during summer (May-October) and winter (November-April) for emissions in Europe and East Asia, as well as from the global shipping sector and global emissions. The species included in this study are aerosols and aerosol precursors (BC, OC, SO2, NH3), as well as ozone precursors (NOx, CO, VOCs), which also influence aerosols to a lesser degree. Emission metrics for global climate responses of these emissions, as well as for CH4, have been calculated using global warming potential (GWP) and global temperature change potential (GTP), based on dedicated RF simulations by four global models. The emission metrics include indirect cloud effects of aerosols and the semi-direct forcing for BC. In addition to the standard emission metrics for pulse and sustained emissions, we have also calculated a new emission metric designed for an emission profile consisting of a ramping period of 15 years followed by sustained emissions, which is more appropriate for a gradual implementation of mitigation policies.For the aerosols, the emission metric values are larger in magnitude for emissions in Europe than East Asia and for summer than winter. A variation is also observed for the ozone precursors, with largest values for emissions in East Asia and winter for CO and in Europe and summer for VOCs. In general, the variations between the emission metrics derived from different models are larger than the variations between regions and seasons, but the regional and seasonal variations for the best estimate also hold for most of the models individually. Further, the estimated climate impact of an illustrative mitigation policy package is

  9. Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008

    NASA Astrophysics Data System (ADS)

    Quennehen, B.; Raut, J.-C.; Law, K. S.; Daskalakis, N.; Ancellet, G.; Clerbaux, C.; Kim, S.-W.; Lund, M. T.; Myhre, G.; Olivié, D. J. L.; Safieddine, S.; Skeie, R. B.; Thomas, J. L.; Tsyro, S.; Bazureau, A.; Bellouin, N.; Hu, M.; Kanakidou, M.; Klimont, Z.; Kupiainen, K.; Myriokefalitakis, S.; Quaas, J.; Rumbold, S. T.; Schulz, M.; Cherian, R.; Shimizu, A.; Wang, J.; Yoon, S.-C.; Zhu, T.

    2016-08-01

    is too weak to explain the differences between the models. Our results rather point to an overestimation of SO2 emissions, in particular, close to the surface in Chinese urban areas. However, we also identify a clear underestimation of aerosol concentrations over northern India, suggesting that the rapid recent growth of emissions in India, as well as their spatial extension, is underestimated in emission inventories. Model deficiencies in the representation of pollution accumulation due to the Indian monsoon may also be playing a role. Comparison with vertical aerosol lidar measurements highlights a general underestimation of scattering aerosols in the boundary layer associated with overestimation in the free troposphere pointing to modelled aerosol lifetimes that are too long. This is likely linked to too strong vertical transport and/or insufficient deposition efficiency during transport or export from the boundary layer, rather than chemical processing (in the case of sulphate aerosols). Underestimation of sulphate in the boundary layer implies potentially large errors in simulated aerosol-cloud interactions, via impacts on boundary-layer clouds.This evaluation has important implications for accurate assessment of air pollutants on regional air quality and global climate based on global model calculations. Ideally, models should be run at higher resolution over source regions to better simulate urban-rural pollutant gradients and/or chemical regimes, and also to better resolve pollutant processing and loss by wet deposition as well as vertical transport. Discrepancies in vertical distributions require further quantification and improvement since these are a key factor in the determination of radiative forcing from short-lived pollutants.

  10. Nucleon-Alpha Particle Disequilibrium and Short-Lived r-Process Radioactivities

    NASA Technical Reports Server (NTRS)

    Meyer, B. S.; Clayton, D. D.; Chellapilla, S.; The, L.-S.

    2002-01-01

    r-Process yields can be extremely sensitive to expansion parameters when a persistent disequilibrium between free nucleons and alpha particles is present. This may provide a natural scenario for understanding the variation of heavy and light r-process isotopes in different r-process events. Additional information is contained in the original extended abstract.

  11. A Short History of the Discovery of Isotopes (and Some of Their Uses)

    ERIC Educational Resources Information Center

    Scott, Dave

    2013-01-01

    This article looks at the events that led to the discovery of isotopes in the early part of the 20th century. It is difficult to claim that the discovery was a single event. A number of famous scientists worked independently to provide the evidence, and the understanding of the need to think differently about atoms gradually emerged. Four varied…

  12. Anthropogenic plutonium-244 in the environment: Insights into plutonium's longest-lived isotope.

    PubMed

    Armstrong, Christopher R; Brant, Heather A; Nuessle, Patterson R; Hall, Gregory; Cadieux, James R

    2016-01-01

    Owing to the rich history of heavy element production in the unique high flux reactors that operated at the Savannah River Site, USA (SRS) decades ago, trace quantities of plutonium with highly unique isotopic characteristics still persist today in the SRS terrestrial environment. Development of an effective sampling, processing, and analysis strategy enables detailed monitoring of the SRS environment, revealing plutonium isotopic compositions, e.g., (244)Pu, that reflect the unique legacy of plutonium production at SRS. This work describes the first long-term investigation of anthropogenic (244)Pu occurrence in the environment. Environmental samples, consisting of collected foot borne debris, were taken at SRS over an eleven year period, from 2003 to 2014. Separation and purification of trace plutonium was carried out followed by three stage thermal ionization mass spectrometry (3STIMS) measurements for plutonium isotopic content and isotopic ratios. Significant (244)Pu was measured in all of the years sampled with the highest amount observed in 2003. The (244)Pu content, in femtograms (fg = 10(-15) g) per gram, ranged from 0.31 fg/g to 44 fg/g in years 2006 and 2003 respectively. In all years, the (244)Pu/(239)Pu atom ratios were significantly higher than global fallout, ranging from 0.003 to 0.698 in years 2014 and 2003 respectively. PMID:26898531

  13. Anthropogenic plutonium-244 in the environment: Insights into plutonium's longest-lived isotope.

    PubMed

    Armstrong, Christopher R; Brant, Heather A; Nuessle, Patterson R; Hall, Gregory; Cadieux, James R

    2016-01-01

    Owing to the rich history of heavy element production in the unique high flux reactors that operated at the Savannah River Site, USA (SRS) decades ago, trace quantities of plutonium with highly unique isotopic characteristics still persist today in the SRS terrestrial environment. Development of an effective sampling, processing, and analysis strategy enables detailed monitoring of the SRS environment, revealing plutonium isotopic compositions, e.g., (244)Pu, that reflect the unique legacy of plutonium production at SRS. This work describes the first long-term investigation of anthropogenic (244)Pu occurrence in the environment. Environmental samples, consisting of collected foot borne debris, were taken at SRS over an eleven year period, from 2003 to 2014. Separation and purification of trace plutonium was carried out followed by three stage thermal ionization mass spectrometry (3STIMS) measurements for plutonium isotopic content and isotopic ratios. Significant (244)Pu was measured in all of the years sampled with the highest amount observed in 2003. The (244)Pu content, in femtograms (fg = 10(-15) g) per gram, ranged from 0.31 fg/g to 44 fg/g in years 2006 and 2003 respectively. In all years, the (244)Pu/(239)Pu atom ratios were significantly higher than global fallout, ranging from 0.003 to 0.698 in years 2014 and 2003 respectively.

  14. Anthropogenic plutonium-244 in the environment: Insights into plutonium’s longest-lived isotope

    PubMed Central

    Armstrong, Christopher R.; Brant, Heather A.; Nuessle, Patterson R.; Hall, Gregory; Cadieux, James R.

    2016-01-01

    Owing to the rich history of heavy element production in the unique high flux reactors that operated at the Savannah River Site, USA (SRS) decades ago, trace quantities of plutonium with highly unique isotopic characteristics still persist today in the SRS terrestrial environment. Development of an effective sampling, processing, and analysis strategy enables detailed monitoring of the SRS environment, revealing plutonium isotopic compositions, e.g., 244Pu, that reflect the unique legacy of plutonium production at SRS. This work describes the first long-term investigation of anthropogenic 244Pu occurrence in the environment. Environmental samples, consisting of collected foot borne debris, were taken at SRS over an eleven year period, from 2003 to 2014. Separation and purification of trace plutonium was carried out followed by three stage thermal ionization mass spectrometry (3STIMS) measurements for plutonium isotopic content and isotopic ratios. Significant 244Pu was measured in all of the years sampled with the highest amount observed in 2003. The 244Pu content, in femtograms (fg = 10−15 g) per gram, ranged from 0.31 fg/g to 44 fg/g in years 2006 and 2003 respectively. In all years, the 244Pu/239Pu atom ratios were significantly higher than global fallout, ranging from 0.003 to 0.698 in years 2014 and 2003 respectively. PMID:26898531

  15. Anthropogenic plutonium-244 in the environment: Insights into plutonium’s longest-lived isotope

    NASA Astrophysics Data System (ADS)

    Armstrong, Christopher R.; Brant, Heather A.; Nuessle, Patterson R.; Hall, Gregory; Cadieux, James R.

    2016-02-01

    Owing to the rich history of heavy element production in the unique high flux reactors that operated at the Savannah River Site, USA (SRS) decades ago, trace quantities of plutonium with highly unique isotopic characteristics still persist today in the SRS terrestrial environment. Development of an effective sampling, processing, and analysis strategy enables detailed monitoring of the SRS environment, revealing plutonium isotopic compositions, e.g., 244Pu, that reflect the unique legacy of plutonium production at SRS. This work describes the first long-term investigation of anthropogenic 244Pu occurrence in the environment. Environmental samples, consisting of collected foot borne debris, were taken at SRS over an eleven year period, from 2003 to 2014. Separation and purification of trace plutonium was carried out followed by three stage thermal ionization mass spectrometry (3STIMS) measurements for plutonium isotopic content and isotopic ratios. Significant 244Pu was measured in all of the years sampled with the highest amount observed in 2003. The 244Pu content, in femtograms (fg = 10-15 g) per gram, ranged from 0.31 fg/g to 44 fg/g in years 2006 and 2003 respectively. In all years, the 244Pu/239Pu atom ratios were significantly higher than global fallout, ranging from 0.003 to 0.698 in years 2014 and 2003 respectively.

  16. Comparisons of the ecology and stable isotopic compositions of living (stained) benthic foraminifera from the Sulu and South China Seas

    NASA Astrophysics Data System (ADS)

    Rathburn, A. E.; Corliss, B. H.; Tappa, K. D.; Lohmann, K. C.

    1996-10-01

    Significant differences are observed between living (Rose Bengal stained) deep-sea benthic foraminifera found in 14 box cores (510-4515 m) from the thermospheric (> 10°C) environments of the Sulu Sea and the psychrospheric (<10°C) conditions in the South Ch ina Sea. Gavelinopsis, Bolivinopsis, Astrononion, Osangularia and Ceratobulimina are common taxa in the South China Sea, but are rare to absent in the Sulu Sea; Siphonina and Valvulineria are dominant genera at certain depths in the Sulu Sea, but are rare to absent in the South China Sea. Faunal differences appear to result from large differences of the bottom-water temperatures (differences from about 6 to 8°C) between these basins. Faunal abundance patterns within each basin are suggested to be related to the organic carbon contents in the sediments, since temperatures, salinities and dissolved oxygen levels of the bottom-waters are relatively uniform. The δ18O values show a > 2‰ range and are similar to those presented by previous workers, but have no consistent relationship with microhabitat preferences. Vertical distribution patterns and carbon isotope compositions of species, however, reflect microhabitat preferences and are consistent with previous observations from other regions. Epifaunal species (0-1 cm interval) such as Cibicidoides pachyderma, Cibicidoides wuellerstorfi, Hoeglundina elegans and Anomalinoides colligera, have higher δ13C values than taxa which have the ability to live deeper within the sediments. Infaunal taxa that live in the upper 2-3 cm, including Uvigerina peregrina, Uvigerina proboscidea, and Bulimina mexicana, have lower δ13C values than epifaunal species, and the deep infaunal species, Chilostomella oolina, has the lowest δ13C. Cibicidoides bradyi and Oridorsalis umbonatus are found between 0 and ˜ 4 cm and have lower carbon isotope values (by > 1.4‰ in some cores) than epifaunal Cibicidoides species. Exceptions to this pattern include the aragonitic species

  17. Osteosarcoma risk after simultaneous incorporation of the long-lived radionuclide 227Ac and the short-lived radionuclide 227Th.

    PubMed

    Müller, W A; Murray, A B; Linzner, U; Luz, A

    1990-01-01

    The effect of injection of 1.85 kBq/kg of the long-lived radionuclide 227Ac on the induction of osteosarcomas in female NMRI mice by different dose levels (18.5, 74, and 185 kBq/kg) of the short-lived radionuclide 227Th was investigated. The highest absolute osteosarcoma incidence was observed with the highest doses of 227Th. Addition of 227Ac resulted in an additional osteosarcoma incidence only at the lowest dose of 227Th and did not affect the osteosarcoma incidence resulting from higher doses of 227Th. The longest times to tumor appearance were observed with 227Ac alone. The latent period in two different age groups (4 weeks and 10-12 weeks) appeared to be similar following injection with combined doses of 227Th and 227Ac but different after injection of each radionuclide alone.

  18. Osteosarcoma risk after simultaneous incorporation of the long-lived radionuclide sup 227 Ac and the short-lived radionuclide sup 227 Th

    SciTech Connect

    Mueller, W.A.M.; Murray, A.B.; Linzner, U.; Luz, A. )

    1990-01-01

    The effect of injection of 1.85 kBq/kg of the long-lived radionuclide {sup 227}Ac on the induction of osteosarcomas in female NMRI mice by different dose levels (18.5, 74, and 185 kBq/kg) of the short-lived radionuclide {sup 227}Th was investigated. The highest absolute osteosarcoma incidence was observed with the highest doses of {sup 227}Th. Addition of {sup 227}Ac resulted in an additional osteosarcoma incidence only at the lowest dose of {sup 227}Th and did not affect the osteosarcoma incidence resulting from higher doses of {sup 227}Th. The longest times to tumor appearance were observed with {sup 227}Ac alone. The latent period in two different age groups (4 weeks and 10-12 weeks) appeared to be similar following injection with combined doses of {sup 227}Th and {sup 227}Ac but different after injection of each radionuclide alone.

  19. Isotopic generator for /sup 212/Pb and /sup 212/Bi

    SciTech Connect

    Zucchini, G.L.; Friedman, A.M.

    1982-01-01

    A large potential exists for the use of short lived alpha emitting isotopes for therapeutic purposes. Most prior research has been performed with isotopes such as /sup 211/At which require a cyclotron for production. It obviously would be more convenient to use a long lived isotopic generator system. For this reason, we have undertaken a study of the properties of several such generators, one of which, /sup 228/Th, is described here.

  20. Short-lived chlorine-36 in a Ca- and Al-rich inclusion from the Ningqiang carbonaceous chondrite

    PubMed Central

    Lin, Yangting; Guan, Yunbin; Leshin, Laurie A.; Ouyang, Ziyuan; Wang, Daode

    2005-01-01

    Excesses of sulfur-36 in sodalite, a chlorine-rich mineral, in a calcium- and aluminum-rich inclusion from the Ningqiang carbonaceous chondrite linearly correlate with chorine/sulfur ratios, providing direct evidence for the presence of short-lived chlorine-36 (with a half-life of 0.3 million years) in the early solar system. The best inferred (36Cl/35Cl)o ratios of the sodalite are ≈5 × 10-6. Different from other short-lived radionuclides, chlorine-36 was introduced into the inclusion by solid-gas reaction during secondary alteration. The alteration reaction probably took place at least 1.5 million years after the first formation of the inclusion, based on the correlated study of the 26Al-26Mg systems of the relict primary minerals and the alteration assemblages, from which we inferred an initial ratio of (36Cl/35Cl)o > 1.6 × 10-4 at the time when calcium- and aluminum-rich inclusions formed. This discovery supports a supernova origin of short-lived nuclides [Cameron, A. G. W., Hoeflich, P., Myers, P. C. & Clayton, D. D. (1995) Astrophys. J. 447, L53; Wasserburg, G. J., Gallino, R. & Busso, M. (1998) Astrophys. J. 500, L189–L193], but presents a serious challenge for local irradiation models [Shu, F. H., Shang, H., Glassgold, A. E. & Lee, T. (1997) Science 277, 1475–1479; Gounelle, M., Shu, F. H., Shang, H., Glassgold, A. E., Rehm, K. E. & Lee, T. (2001) Astrophys. J. 548, 1051–1070]. Furthermore, the short-lived 36Cl may serve as a unique fine-scale chronometer for volatile-rock interaction in the early solar system because of its close association with aqueous and/or anhydrous alteration processes. PMID:15671168

  1. Short-lived chlorine-36 in a Ca- and Al-rich inclusion from the Ningqiang carbonaceous chondrite.

    PubMed

    Lin, Yangting; Guan, Yunbin; Leshin, Laurie A; Ouyang, Ziyuan; Wang, Daode

    2005-02-01

    Excesses of sulfur-36 in sodalite, a chlorine-rich mineral, in a calcium- and aluminum-rich inclusion from the Ningqiang carbonaceous chondrite linearly correlate with chorine/sulfur ratios, providing direct evidence for the presence of short-lived chlorine-36 (with a half-life of 0.3 million years) in the early solar system. The best inferred (36Cl/35Cl)o ratios of the sodalite are approximately 5 x 10(-6). Different from other short-lived radionuclides, chlorine-36 was introduced into the inclusion by solid-gas reaction during secondary alteration. The alteration reaction probably took place at least 1.5 million years after the first formation of the inclusion, based on the correlated study of the 26Al-26Mg systems of the relict primary minerals and the alteration assemblages, from which we inferred an initial ratio of (36Cl/35Cl)o > or = 1.6 x 10(-4) at the time when calcium- and aluminum-rich inclusions formed. This discovery supports a supernova origin of short-lived nuclides [Cameron, A. G. W., Hoeflich, P., Myers, P. C. & Clayton, D. D. (1995) Astrophys. J. 447, L53; Wasserburg, G. J., Gallino, R. & Busso, M. (1998) Astrophys. J. 500, L189-L193], but presents a serious challenge for local irradiation models [Shu, F. H., Shang, H., Glassgold, A. E. & Lee, T. (1997) Science 277, 1475-1479; Gounelle, M., Shu, F. H., Shang, H., Glassgold, A. E., Rehm, K. E. & Lee, T. (2001) Astrophys. J. 548, 1051-1070]. Furthermore, the short-lived 36Cl may serve as a unique fine-scale chronometer for volatile-rock interaction in the early solar system because of its close association with aqueous and/or anhydrous alteration processes. PMID:15671168

  2. First Isochronous Time-of-Flight Mass Measurements of Short-Lived Projectile Fragments in the ESR

    SciTech Connect

    Stadlmann, J.; Geissel, H.; Hausmann, M.; Nolden, F.; Radon, T.; Schatz, H.; Scheidenberger, C.; Attallah, F.; Beckert, K.; Bosch, F.; Falch, M.; Franczak, B.; Franzke, B.; Kerscher, Th.; Klepper, O.; Kluge, H.J.; Kozhuharov, C.; Loebner, K.E.G.; Muenzenberg, G.; Novikov, Yu.N.; Steck, M.; Sun, Z.; Suemmerer, K.; Weick, H.; Wollnik, H.

    2000-12-31

    A new method for precise mass measurements of short-lived hot nuclei is presented. These nuclei were produced via projectile fragmentation, separated with the FRS and injected into the storage ring ESR being operated in the isochronous mode. The revolution time of the ions is measured with a time-of-flight detector sensitive to single particles. This new method allows access to exotic nuclei with half-lives in the microsecond region. First results from this novel method obtained with measurements on neutron-deficient fragments of a chromium primary beam with half-lives down to 50 ms are reported. A precision of {delta}m/m {<=} 5 {center_dot} 10{sup -6} has been achieved.

  3. Mapping loci associated with tail color and sex determination in the short-lived fish Nothobranchius furzeri.

    PubMed

    Valenzano, Dario Riccardo; Kirschner, Jeanette; Kamber, Roarke A; Zhang, Elisa; Weber, David; Cellerino, Alessandro; Englert, Christoph; Platzer, Matthias; Reichwald, Kathrin; Brunet, Anne

    2009-12-01

    The African fish Nothobranchius furzeri is the shortest-lived vertebrate species that can reproduce in captivity, with a median life span of 9-11 weeks for the shortest-lived strain. Natural populations of N. furzeri display differences in life span, aging biomarkers, behavior, and color, which make N. furzeri a unique vertebrate system for studying the genetic basis of these traits. We mapped regions of the genome involved in sex determination and tail color by genotyping microsatellite markers in the F(2) progeny of a cross between a short-lived, yellow-tailed strain and a long-lived, red-tailed strain of N. furzeri. We identified one region linked with the yellow/red tail color that maps close to melanocortin 1 receptor (mc1r), a gene involved in pigmentation in several vertebrate species. Analysis of the segregation of sex-linked markers revealed that N. furzeri has a genetic sex determination system with males as the heterogametic sex and markedly reduced recombination in the male sex-determining region. Our results demonstrate that both naturally-evolved pigmentation differences and sex determination in N. furzeri are controlled by simple genetic mechanisms and set the stage for the molecular genetic dissection of factors underlying such traits. The microsatellite-based linkage map we developed for N. furzeri will also facilitate analysis of the genetic architecture of traits that characterize this group of vertebrates, including short life span and adaptation to extreme environmental conditions.

  4. Synthesis of an Isotopically Labeled Naphthalene Derivative That Supports a Long-Lived Nuclear Singlet State

    PubMed Central

    2015-01-01

    The synthesis of an octa-alkoxy substituted isotopically labeled naphthalene derivative, shown to have excellent properties in singlet NMR experiments, is described. This highly substituted naphthalene system, which incorporates an adjacent 13C spin pair, is readily accessed from a commercially available 13C2-labeled building block via sequential thermal alkynyl- and arylcyclobutenone rearrangements. The synthetic route incorporates a simple desymmetrization approach leading to a small difference in the chemical shifts of the 13C spin pair, a design constraint crucial for accessing nuclear singlet order. PMID:25898076

  5. Use of Stable Isotopes to Follow Intracellular Water Dynamics in Living Cells

    SciTech Connect

    Kreuzer, Helen W.; Hegg, Eric L.

    2012-01-28

    Despite the importance of water to cell structure and function, intracellular water dynamics are poorly understood. A new method based on isotope ratio measurements has revealed that a substantial portion of the O and H atoms in the intracellular water of rapidly-dividing cultured cells is derived from metabolic activity, and not from environmental water. These findings have led to a dynamic model of intracellular water composition: (1) Intracellular water is composed of water that diffuses in from the extracellular environment and water that is created as a result of metabolic activity. (2) The relative amounts of environmental and metabolic water inside a cell are a function of the cell's metabolic activity. (3) The oxygen and hydrogen isotope ratios of cellular metabolites are a function of those of intracellular water, and therefore reflect the metabolic activity of the cell at the time of biosynthesis. Data from gram-positive and gram-negative bacteria as well as cultured mammalian cells are consistent with the model.

  6. Live, Online Short-Courses: A Case Study of Innovative Teacher Professional Development

    ERIC Educational Resources Information Center

    Marrero, Meghan E.; Woodruff, Karen A.; Schuster, Glen S.; Riccio, Jessica Fitzsimons

    2010-01-01

    Teachers are searching for new venues through which they may meet stringent professional development requirements. Under competitive funding from NASA's (National Aeronautics and Space Administration) Office of Education and the NASA Explorer Schools Project, U.S. Satellite Laboratory, Inc. created a series of live, online, interactive…

  7. VLA Observations Confirm Origin of Gamma Ray Bursts in Short-Lived Stars

    NASA Astrophysics Data System (ADS)

    1998-06-01

    Radio telescope studies of the fiery afterglow of a Gamma Ray Burst have provided astronomers with the best clues yet about the origins of these tremendous cosmic cataclysms since their discovery more than 30 years ago. Observations with the National Science Foundation's (NSF) Very Large Array (VLA) radio telescope confirm that a blast seen to occur on March 29 had its origin in a star-forming region in a distant galaxy. "There are two leading theories for the causes of Gamma Ray Bursts," said Dale Frail of the NSF National Radio Astronomy Observatory (NRAO) in Socorro, NM. "According to one theory, the blasts occur in the death throes of pairs of old stars. The other requires them to arise from exploding, massive, short-lived stars that still reside within the star-forming gas and dust from which they formed. The VLA studies of the burst show that at least this one almost certainly occurred within a star-forming region. This result also explains why half of the Gamma Ray Burst afterglows are not detected by optical telescopes." Frail heads a VLA observing team including Greg Taylor, also of NRAO, and Shri Kulkarni of Caltech, that reported its findings to the American Astronomical Society meeting in San Diego, CA. The March 29 burst was seen clearly by radio telescopes (the accompanying image is GRB 980329 as seen by the VLA) but only very faintly with optical instruments. "That is extremely important," said Taylor. "This burst was very faint at visible wavelengths, brighter at infrared wavelengths and brighter still at radio wavelengths. This is a clear indication that the exploding object was surrounded by dust. Dust is most commonly found in star-forming regions." This strongly favors one of the two leading theories about Gamma Ray Bursts over the other. One explanation for these tremendously energetic fireballs is that a pair of superdense neutron stars collides. The other is that a single, very massive star explodes in a "hypernova," more powerful than a

  8. Atomic mass measurements of short-lived nuclides around the doubly-magic 208Pb

    NASA Astrophysics Data System (ADS)

    Weber, C.; Audi, G.; Beck, D.; Blaum, K.; Bollen, G.; Herfurth, F.; Kellerbauer, A.; Kluge, H.-J.; Lunney, D.; Schwarz, S.

    2008-04-01

    Accurate atomic mass measurements of neutron-deficient and neutron-rich nuclides around the doubly-magic 208Pb and of neutron-rich cesium isotopes were performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The masses of 145,147Cs, 181,183Tl, 186Tl m, 187Tl m, 196Tl m, 205Tl, 197Pb m, 208Pb, 190-197Bi, 209,215,216Bi, 203,205,229Fr, and 214,229,230Ra were determined. The obtained relative mass uncertainty in the range of 2×10 to 2×10 is not only required for safe identification of isomeric states but also allows mapping the detailed structure of the mass surface. A mass adjustment procedure was carried out and the results included into the Atomic Mass Evaluation. The resulting separation energies are discussed and the mass spectrometric and laser spectroscopic data are examined for possible correlations.

  9. Living to the range limit: consumer isotopic variation increases with environmental stress

    PubMed Central

    O’Connor, Nessa E.

    2016-01-01

    Background: Theoretically, each species’ ecological niche is phylogenetically-determined and expressed spatially as the species’ range. However, environmental stress gradients may directly or indirectly decrease individual performance, such that the precise process delimiting a species range may not be revealed simply by studying abundance patterns. In the intertidal habitat the vertical ranges of marine species may be constrained by their abilities to tolerate thermal and desiccation stress, which may act directly or indirectly, the latter by limiting the availability of preferred trophic resources. Therefore, we expected individuals at greater shore heights to show greater variation in diet alongside lower indices of physiological condition. Methods: We sampled the grazing gastropod Echinolittorina peruviana from the desert coastline of northern Chile at three shore heights, across eighteen regionally-representative shores. Stable isotope values (δ13C and δ15N) were extracted from E. peruviana and its putative food resources to estimate Bayesian ellipse area, carbon and nitrogen ranges and diet. Individual physiological condition was tracked by muscle % C and % N. Results: There was an increase in isotopic variation at high shore levels, where E. peruviana’s preferred resource, tide-deposited particulate organic matter (POM), appeared to decrease in dietary contribution, and was expected to be less abundant. Both muscle % C and % N of individuals decreased with height on the shore. Discussion: Individuals at higher stress levels appear to be less discriminating in diet, likely because of abiotic forcing, which decreases both consumer mobility and the availability of a preferred resource. Abiotic stress might be expected to increase trophic variation in other selective dietary generalist species. Where this coincides with a lower physiological condition may be a direct factor in setting their range limit. PMID:27280067

  10. [Survival in advanced age--a comparison of short- and long-lived probands of the Bonn gerontologic longitudinal study].

    PubMed

    Fooken, I

    1984-01-01

    A comparison between rather short-lived (n = 60) and rather long-lived (n = 88) participants of the initial sample of the Bonn longitudinal study on aging (BOLSA) yielded evidence - with regard to differences in the central tendencies of these two groups - for a variety of determinants of longevity in old age. The statistical analyses included eight constructs or clusters of variables, respectively, that were either empirically or theoretically based and were supposed to have predictive power (intelligence, health status, satisfaction, personality, family involvement, socioeconomic/ecological aspects, coping techniques/dominant themes of life, general social participation). Within each "cluster", it could be referred to several different aspects. Besides defining general characteristics of longevious people, the purpose of the study was to look for differentiating aspects. Thus, a host of evidence was yielded for gender- and cohort-linked differences in the structure and relevance of the included central clusters with regard to "prediction" of advanced longevity in old age.

  11. Isotopic anomalies in extraterrestrial grains.

    PubMed

    Ireland, T R

    1996-03-01

    Isotopic compositions are referred to as anomalous if the isotopic ratios measured cannot be related to the terrestrial (solar) composition of a given element. While small effects close to the resolution of mass spectrometric techniques can have ambiguous origins, the discovery of large isotopic anomalies in inclusions and grains from primitive meteorites suggests that material from distinct sites of stellar nucleosynthesis has been preserved. Refractory inclusions, which are predominantly composed of the refractory oxides of Al, Ca, Ti, and Mg, in chondritic meteorites commonly have excesses in the heaviest isotopes of Ca, Ti, and Cr which are inferred to have been produced in a supernova. Refractory inclusions also contain excess 26Mg from short lived 26Al decay. However, despite the isotopic anomalies indicating the preservation of distinct nucleosynthetic sites, refractory inclusions have been processed in the solar system and are not interstellar grains. Carbon (graphite and diamond) and silicon carbide grains from the same meteorites also have large isotopic anomalies but these phases are not stable in the oxidized solar nebula which suggests that they are presolar and formed in the circumstellar atmospheres of carbon-rich stars. Diamond has a characteristic signature enriched in the lightest and heaviest isotopes of Xe, and graphite shows a wide range in C isotopic compositions. SiC commonly has C and N isotopic signatures which are characteristic of H-burning in the C-N-O cycle in low-mass stars. Heavier elements such as Si, Ti, Xe, Ba, and Nd, carry an isotopic signature of the s-process. A minor population of SiC (known as Grains X, ca. 1%) are distinct in having decay products of short lived isotopes 26Al (now 26Mg), 44Ti (now 44Ca), and 49V (now 49Ti), as well as 28Si excesses which are characteristic of supernova nucleosynthesis. The preservation of these isotopic anomalies allows the examination of detailed nucleosynthetic pathways in stars. PMID

  12. Isotopic anomalies in extraterrestrial grains.

    PubMed

    Ireland, T R

    1996-03-01

    Isotopic compositions are referred to as anomalous if the isotopic ratios measured cannot be related to the terrestrial (solar) composition of a given element. While small effects close to the resolution of mass spectrometric techniques can have ambiguous origins, the discovery of large isotopic anomalies in inclusions and grains from primitive meteorites suggests that material from distinct sites of stellar nucleosynthesis has been preserved. Refractory inclusions, which are predominantly composed of the refractory oxides of Al, Ca, Ti, and Mg, in chondritic meteorites commonly have excesses in the heaviest isotopes of Ca, Ti, and Cr which are inferred to have been produced in a supernova. Refractory inclusions also contain excess 26Mg from short lived 26Al decay. However, despite the isotopic anomalies indicating the preservation of distinct nucleosynthetic sites, refractory inclusions have been processed in the solar system and are not interstellar grains. Carbon (graphite and diamond) and silicon carbide grains from the same meteorites also have large isotopic anomalies but these phases are not stable in the oxidized solar nebula which suggests that they are presolar and formed in the circumstellar atmospheres of carbon-rich stars. Diamond has a characteristic signature enriched in the lightest and heaviest isotopes of Xe, and graphite shows a wide range in C isotopic compositions. SiC commonly has C and N isotopic signatures which are characteristic of H-burning in the C-N-O cycle in low-mass stars. Heavier elements such as Si, Ti, Xe, Ba, and Nd, carry an isotopic signature of the s-process. A minor population of SiC (known as Grains X, ca. 1%) are distinct in having decay products of short lived isotopes 26Al (now 26Mg), 44Ti (now 44Ca), and 49V (now 49Ti), as well as 28Si excesses which are characteristic of supernova nucleosynthesis. The preservation of these isotopic anomalies allows the examination of detailed nucleosynthetic pathways in stars.

  13. Age-dependent inhalation doses to members of the public from indoor short-lived radon progeny.

    PubMed

    Brudecki, K; Li, W B; Meisenberg, O; Tschiersch, J; Hoeschen, C; Oeh, U

    2014-08-01

    The main contribution of radiation dose to the human lungs from natural exposure originates from short-lived radon progeny. In the present work, the inhalation doses from indoor short-lived radon progeny, i.e., (218)Po, (214)Pb, (214)Bi, and (214)Po, to different age groups of members of the public were calculated. In the calculations, the age-dependent systemic biokinetic models of polonium, bismuth, and lead published by the International Commission on Radiological Protection (ICRP) were adopted. In addition, the ICRP human respiratory tract and gastrointestinal tract models were applied to determine the deposition fractions in different regions of the lungs during inhalation and exhalation, and the absorption fractions of radon progeny in the alimentary tract. Based on the calculated contribution of each progeny to equivalent dose and effective dose, the dose conversion factor was estimated, taking into account the unattached fraction of aerosols, attached aerosols in the nucleation, accumulation and coarse modes, and the potential alpha energy concentration fraction in indoor air. It turned out that for each progeny, the equivalent doses to extrathoracic airways and the lungs are greater than those to other organs. The contribution of (214)Po to effective dose is much smaller compared to that of the other short-lived radon progeny and can thus be neglected in the dose assessment. In fact, 90 % of the effective dose from short-lived radon progeny arises from (214)Pb and (214)Bi, while the rest is from (218)Po. The dose conversion factors obtained in the present study are 17 and 18 mSv per working level month (WLM) for adult female and male, respectively. This compares to values ranging from 6 to 20 mSv WLM(-1) calculated by other investigators. The dose coefficients of each radon progeny calculated in the present study can be used to estimate the radiation doses for the population, especially for small children and women, in specific regions of the world

  14. Bayes’ Theorem and Early Solar Short-lived Radionuclides: The Case for an Unexceptional Origin for the Solar System

    NASA Astrophysics Data System (ADS)

    Young, Edward D.

    2016-08-01

    The presence of excesses of short-lived radionuclides in the early solar system evidenced in meteorites has been taken as testament to close encounters with exotic nucleosynthetic sources, including supernovae or AGB stars. An analysis of the likelihoods associated with different sources of these extinct nuclides in the early solar system indicates that, rather than being exotic, their abundances were typical of star-forming regions like those observed today in the Galaxy. The radiochemistry of the early solar system is therefore unexceptional, being the consequence of extensive averaging of solids from molecular clouds.

  15. Memory inflation during chronic viral infection is maintained by continuous production of short-lived, functional T cells.

    PubMed

    Snyder, Christopher M; Cho, Kathy S; Bonnett, Elizabeth L; van Dommelen, Serani; Shellam, Geoffrey R; Hill, Ann B

    2008-10-17

    During persistent murine cytomegalovirus (MCMV) infection, the T cell response is maintained at extremely high intensity for the life of the host. These cells closely resemble human CMV-specific cells, which compose a major component of the peripheral T cell compartment in most people. Despite a phenotype that suggests extensive antigen-driven differentiation, MCMV-specific T cells remain functional and respond vigorously to viral challenge. We hypothesized that a low rate of antigen-driven proliferation would account for the maintenance of this population. Instead, we found that most of these cells divided only sporadically in chronically infected hosts and had a short half-life in circulation. The overall population was supported, at least in part, by memory T cells primed early in infection, as well as by recruitment of naive T cells at late times. Thus, these data show that memory inflation is maintained by a continuous replacement of short-lived, functional cells during chronic MCMV infection.

  16. Time-series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream

    NASA Astrophysics Data System (ADS)

    Duvert, C.; Stewart, M. K.; Cendón, D. I.; Raiber, M.

    2015-08-01

    A major limitation to the accurate assessment of streamwater transit time (TT) stems from the use of stable isotopes or chloride as hydrological tracers, because these tracers are blind to older contributions. Also, while catchment processes are highly non-stationary, the importance of temporal dynamics in older water TT has often been overlooked. In this study we used lumped convolution models to examine time-series of tritium, stable isotopes and chloride in rainfall, streamwater and groundwater of a catchment located in subtropical Australia. Our objectives were to assess the different contributions to streamflow and their variations over time, and to understand the relationships between streamwater TT and groundwater residence time. Stable isotopes and chloride provided consistent estimates of TT in the upstream part of the catchment. A young component to streamflow was identified that was partitioned into quickflow (mean TT ≈ 2 weeks) and discharge from the fractured igneous rocks forming the headwaters (mean TT ≈ 0.3 years). The use of tritium was beneficial for determining an older contribution to streamflow in the downstream area. The best fits were obtained for a mean TT of 16-25 years for this older groundwater component. This was significantly lower than the residence time calculated for the alluvial aquifer feeding the stream downstream (≈ 76-102 years), outlining the fact that water exiting the catchment and water stored in it had distinctive age distributions. When simulations were run separately on each tritium streamwater sample, the TT of old water fraction varied substantially over time, with values averaging 17 ± 6 years at low flow and 38 ± 15 years after major recharge events. This was interpreted as the flushing out of deeper, older waters shortly after recharge by the resulting pressure wave propagation. Overall, this study shows the usefulness of collecting tritium data in streamwater to document short-term variations in the older

  17. Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream

    NASA Astrophysics Data System (ADS)

    Duvert, C.; Stewart, M. K.; Cendón, D. I.; Raiber, M.

    2016-01-01

    A major limitation to the assessment of catchment transit time (TT) stems from the use of stable isotopes or chloride as hydrological tracers, because these tracers are blind to older contributions. Yet, accurately capturing the TT of the old water fraction is essential, as is the assessment of its temporal variations under non-stationary catchment dynamics. In this study we used lumped convolution models to examine time series of tritium, stable isotopes and chloride in rainfall, streamwater and groundwater of a catchment located in subtropical Australia. Our objectives were to determine the different contributions to streamflow and their variations over time, and to understand the relationship between catchment TT and groundwater residence time. Stable isotopes and chloride provided consistent estimates of TT in the upstream part of the catchment. A young component to streamflow was identified that was partitioned into quickflow (mean TT ≈ 2 weeks) and discharge from the fractured igneous rocks forming the headwaters (mean TT ≈ 0.3 years). The use of tritium was beneficial for determining an older contribution to streamflow in the downstream area. The best fits between measured and modelled tritium activities were obtained for a mean TT of 16-25 years for this older groundwater component. This was significantly lower than the residence time calculated for groundwater in the alluvial aquifer feeding the stream downstream ( ≈ 76-102 years), emphasising the fact that water exiting the catchment and water stored in it had distinctive age distributions. When simulations were run separately on each tritium streamwater sample, the TT of old water fraction varied substantially over time, with values averaging 17 ± 6 years at low flow and 38 ± 15 years after major recharge events. This counterintuitive result was interpreted as the flushing out of deeper, older waters shortly after recharge by the resulting pressure wave propagation. Overall, this study shows the

  18. Metabolic rate and membrane fatty acid composition in birds: a comparison between long-living parrots and short-living fowl.

    PubMed

    Montgomery, Magdalene K; Hulbert, A J; Buttemer, William A

    2012-01-01

    Both basal metabolic rate (BMR) and maximum lifespan potential (MLSP) vary with body size in mammals and birds and it has been suggested that these are mediated through size-related variation in membrane fatty acid composition. Whereas the physical properties of membrane fatty acids affect the activity of membrane proteins and, indirectly, an animal's BMR, it is the susceptibility of those fatty acids to peroxidation which influence MLSP. Although there is a correlation between body size and MLSP, there is considerable MLSP variation independent of body size. For example, among bird families, Galliformes (fowl) are relatively short-living and Psittaciformes (parrots) are unusually long-living, with some parrot species reaching maximum lifespans of more than 100 years. We determined BMR and tissue phospholipid fatty acid composition in seven tissues from three species of parrots with an average MLSP of 27 years and from two species of quails with an average MLSP of 5.5 years. We also characterised mitochondrial phospholipids in two of these tissues. Neither BMR nor membrane susceptibility to peroxidation corresponded with differences in MLSP among the birds we measured. We did find that (1) all birds had lower n-3 polyunsaturated fatty acid content in mitochondrial membranes compared to those of the corresponding tissue, and that (2) irrespective of reliance on flight for locomotion, both pectoral and leg muscle had an almost identical membrane fatty acid composition in all birds.

  19. Live-cell vibrational imaging of choline metabolites by stimulated Raman scattering coupled with isotope-based metabolic labeling

    PubMed Central

    Hu, Fanghao; Wei, Lu; Zheng, Chaogu; Shen, Yihui

    2014-01-01

    Choline is a small molecule that occupies a key position in the biochemistry of all living organisms. Recent studies have strongly implicated choline metabolites in cancer, atherosclerosis and nervous system development. To detect choline and its metabolites, existing physical methods such as magnetic resonance spectroscopy and positron emission tomography, are often limited by the poor spatial resolution and substantial radiation dose. Fluorescence imaging, although with submicrometer resolution, requires introduction of bulky fluorophores and thus is difficult in labeling the small choline molecule. By combining the emerging bond-selective stimulated Raman scattering microscopy with metabolic incorporation of deuterated choline, herein we have achieved high resolution imaging of choline-containing metabolites in living mammalian cell lines, primary hippocampal neurons and multicellular organism C. elegans. Different subcellular distributions of choline metabolites are observed between cancer cells and non-cancer cells, which may reveal functional difference in the choline metabolism and lipid-mediated signaling events. In neurons, choline incorporation is visualized within both soma and neurites, where choline metabolites are more evenly distributed compared to the protein. Furthermore, choline localization is also observed in the pharynx region of C. elegans larvae, consistent with its organogenesis mechanism. These applications demonstrate the potential of isotope-based stimulated Raman scattering microscopy for future choline-related disease detection and development monitoring in vivo. PMID:24555181

  20. Rare Isotope Accelerators

    NASA Astrophysics Data System (ADS)

    Savard, Guy

    2002-04-01

    The next frontier for low-energy nuclear physics involves experimentation with accelerated beams of short-lived radioactive isotopes. A new facility, the Rare Isotope Accelerator (RIA), is proposed to produce large amount of these rare isotopes and post-accelerate them to energies relevant for studies in nuclear physics, astrophysics and the study of fundamental interactions at low energy. The basic science motivation for this facility will be introduced. The general facility layout, from the 400 kW heavy-ion superconducting linac used for production of the required isotopes to the novel production and extraction schemes and the highly efficient post-accelerator, will be presented. Special emphasis will be put on a number of technical breakthroughs and recent R&D results that enable this new facility.

  1. β-decay half-lives of new neutron-rich rare-earth isotopes 159Pm,162Sm, and 166Gd

    NASA Astrophysics Data System (ADS)

    Ichikawa, S.; Asai, M.; Tsukada, K.; Haba, H.; Nagame, Y.; Shibata, M.; Sakama, M.; Kojima, Y.

    2005-06-01

    The new neutron-rich rare-earth isotopes 159Pm, 162Sm, and 166Gd produced in the proton-induced fission of 238U were identified using the JAERI on-line isotope separator (JAERI-ISOL) coupled to a gas-jet transport system. The half-lives of 159Pm, 162Sm, and 166Gd were determined to be 1.5 ± 0.2, 2.4 ± 0.5, and 4.8 ± 1.0 s respectively. The partial decay scheme of 166Gd was constructed from γγ-coincidence data. A more accurate half-life value of 25.6 ± 2.2 s was obtained for the previously identified isotope 166Tb. The half-lives measured in the present study are in good agreement with the theoretical predictions calculated by the second generation of the gross theory with the atomic masses evaluated by Audi and Wapstra.

  2. Bioanalytical and chemical sensors using living taste, olfactory, and neural cells and tissues: a short review.

    PubMed

    Wu, Chunsheng; Lillehoj, Peter B; Wang, Ping

    2015-11-01

    Biosensors utilizing living tissues and cells have recently gained significant attention as functional devices for chemical sensing and biochemical analysis. These devices integrate biological components (i.e. single cells, cell networks, tissues) with micro-electro-mechanical systems (MEMS)-based sensors and transducers. Various types of cells and tissues derived from natural and bioengineered sources have been used as recognition and sensing elements, which are generally characterized by high sensitivity and specificity. This review summarizes the state of the art in tissue- and cell-based biosensing platforms with an emphasis on those using taste, olfactory, and neural cells and tissues. Many of these devices employ unique integration strategies and sensing schemes based on sensitive transducers including microelectrode arrays (MEAs), field effect transistors (FETs), and light-addressable potentiometric sensors (LAPSs). Several groups have coupled these hybrid biosensors with microfluidics which offers added benefits of small sample volumes and enhanced automation. While this technology is currently limited to lab settings due to the limited stability of living biological components, further research to enhance their robustness will enable these devices to be employed in field and clinical settings.

  3. Recruitment in invertebrates with short-lived larvae: the case of the bryozoan Disporella hispida (Fleming)

    NASA Astrophysics Data System (ADS)

    Mariani, Simone

    2003-03-01

    Temporal and spatial recruitment patterns of the cyclostome bryozoan Disporella hispida were monitored using settlement plates arranged along three benthic communities of an artificial reef at Blanes (NE Spain, NW Mediterranean). At the study site, the species mainly inhabits semi-obscure caves. By studying recruitment over one year I first inferred the larval release period for D. hispida and described its temporal occurrence in the communities and stations studied. Secondly, I attempted to determine whether the predicted restricted dispersal may account for the species' distribution at the study site. To this purpose, I compared the distribution of early recruits (15 days old) with that of adults. I also investigated environmental factors which may affect the extent of larval dispersal, and described the effects of post-recruitment processes occurring over a 4-month period. The brooding period, inferred from the study of early recruitment, was linked to spring-increments and autumn-decrements of water temperatures. Early recruits were distributed non-randomly in the communities and stations studied, being most abundant in the habitats where adults live. Strong hydrodynamic events seemed to modify this pattern, allowing recruitment out of the parental communities, and may hinder settlement. Post-recruitment mortality events were likely to prevent colonisation of habitats where the species do not live. Overall, philopatry and low post-recruitment mortality in the parental communities appeared to be the main mechanisms determining the distribution of D. hispida at the study site.

  4. Bioanalytical and chemical sensors using living taste, olfactory, and neural cells and tissues: a short review.

    PubMed

    Wu, Chunsheng; Lillehoj, Peter B; Wang, Ping

    2015-11-01

    Biosensors utilizing living tissues and cells have recently gained significant attention as functional devices for chemical sensing and biochemical analysis. These devices integrate biological components (i.e. single cells, cell networks, tissues) with micro-electro-mechanical systems (MEMS)-based sensors and transducers. Various types of cells and tissues derived from natural and bioengineered sources have been used as recognition and sensing elements, which are generally characterized by high sensitivity and specificity. This review summarizes the state of the art in tissue- and cell-based biosensing platforms with an emphasis on those using taste, olfactory, and neural cells and tissues. Many of these devices employ unique integration strategies and sensing schemes based on sensitive transducers including microelectrode arrays (MEAs), field effect transistors (FETs), and light-addressable potentiometric sensors (LAPSs). Several groups have coupled these hybrid biosensors with microfluidics which offers added benefits of small sample volumes and enhanced automation. While this technology is currently limited to lab settings due to the limited stability of living biological components, further research to enhance their robustness will enable these devices to be employed in field and clinical settings. PMID:26308143

  5. Studies of images of short-lived events using ERTS data. [forest fires, oil spills, vegetation damage, volcanoes, storm ridges, earthquakes, and floods

    NASA Technical Reports Server (NTRS)

    Deutschman, W. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Detection of short-lived events has continued. Forest fires, oil spills, vegetation damage, volcanoes, storm ridges, earthquakes, and floods have been detected and analyzed.

  6. Measurement of short-lived radon progenies by simultaneous αγ-spectrometry at the German radon reference chamber

    NASA Astrophysics Data System (ADS)

    Paul, A.; Röttger, S.; Honig, A.; Sulima, T.; Buchholz, A.; Keyser, Uwe

    1999-02-01

    In the German radon reference chamber, the short-lived radon progenies are separated by a sample tube according to the attached or unattached fraction, while their activity concentration is afterwards measured by simultaneous α- and γ-spectrometry. The results are expressed by the equilibrium factor F and the unattached fraction fp (International Commission on Radiological Protection, ICRP Publication 50, Ann. ICRP 17 (1987) 1). Both F and fp, can be therefore studied with respect to the full set of environmental parameters, e.g. temperature, humidity, air pressure and aerosol concentration (Honig et al., Nucl. Instr. and Meth. A 416 (1998) 525). Up to now, well-defined and stable equilibrium factors in the interval from 0.1 to 1.0 have been established. In correlation with this, the unattached fraction can be varied from 0.01 to 0.9. The sample and measuring technique for the short-lived radon progenies described in this work is the basis for fundamental studies with regard to the equilibrium factor and the unattached fraction as well as for application as a calibration facility.

  7. Resistance to prooxidant agent paraquat in the short- and long-lived lines of the seed beetle (Acanthoscelides obtectus).

    PubMed

    Lazarević, Jelica; Dorđević, Mirko; Stojković, Biljana; Tucić, Nikola

    2013-04-01

    In the present study we test whether variation in resistance to paraquat (PQ), a free radical generator, correlates with variation in longevity in two sets of seed beetles (Acanthoscelides obtectus) experimental lines that were selected either for early reproduction and short-life or late reproduction and long-life. Long-lived late reproduction lines (L) showed increased resistance to PQ, while opposite was true for short-lived early reproduction line (E). Striking outcome of the selection for early and late reproduction in A. obtectus is asymmetry of responses to alternate mating schedules. The intensity of response depended on selection regime, sex and PQ dose. Evolution of longevity and PQ resistance was faster in L than E selection regime, and in females than males. To understand how age-specific mortality rates are affected by PQ we decomposed post-stress mortality data (using Gompertz mortality model) into initial mortality rate, which reflects basal vulnerability to stresses and age-specific mortality rate, which concerns the rate of increase in stress vulnerability, i.e. the rate of senescence. By estimating the parameters of the Gompertz mortality model we have shown that longevity reduction caused by PQ was the consequence of the increased baseline mortality rather than a speed up of the rate of ageing. PMID:23515831

  8. Determination of k0-factors of short-lived nuclides and application of k0-NAA to selected trace elements

    NASA Astrophysics Data System (ADS)

    Acharya, R.; Holzbecher, J.; Chatt, A.

    2012-07-01

    As part of the standardization program of k0-based NAA (k0-NAA) methods at the Dalhousie University SLOWPOKE-2 reactor (DUSR) facility, the k0-factors of 15 analytically important short-lived nuclides (half-life <65 s) were determined with respect to gold (197Au). The elemental standards used were prepared mostly from their primary standard solutions. The samples were irradiated in both inner and outer pneumatic sites of the DUSR facility and counted using an HPGe-detector coupled to an ORTEC's digital gamma-ray spectrometer. The k0-factors determined using both inner and outer irradiation sites were found to be within ±5% with respect to either recommended or literature values in most cases. The Z-score values at 95% confidence level were found to be in the range of ±0.03-1.6. The k0-NAA method was applied to three different NIST standard reference materials (SRMs) and concentrations of six elements, namely Ag, F, Hf, Rb, Sc, and Se were determined using their short-lived nuclides. The concentrations of these elements were also determined by relative NAA method for comparison purposes.

  9. Short- and long-lived radionuclide particle size measurements in a uranium mine

    SciTech Connect

    Tu, Keng-Wu; Fisenne, I.M.; Hutter, A.R.

    1997-04-01

    The radon-222 progeny and long-lived radionuclide measurements were done in a wet underground uranium mine in Saskatchewan, Canada, on Nov. 8-12, 1995. Radon-222 in the mine varied from 2 kBq/m{sup 3} at 90 m below surface to 12 kBq/m{sup 3} in the mining areas, 240 m below surface. Radon-222 progeny activity and potential alpha energy concentration appear affected by the airborne particle number concentration and size distribution. Particle number was up to 200x10{sup 3}/cm{sup 3}. Only an accumulation mode (30-1000 nm) and some bimodal size distributions in this accumulation size range were significant. Diesel particles and combustion particles from burning propane caused a major modal diameter shift to a smaller size range (50-85 nm) compared with previous values (100-200 nm). The high particle number reduced the unattached progeny (0.5-2 nm) to >5%. The nuclei mode (2-30 nm) in this test was nonexistent, and the coarse mode (>1000 nm), except from the drilling areas and on the stopes, was mostly not measurable. Airborne particle total mass and long- lived radionuclide alpha activity concentrations were very low (80- 100 {mu}g/m{sup 3} and 4-5 mBq/m{sup 3}) owing to high ventilation rates. Mass-weighted size distributions were trimodal, with the major mode at the accumulation size region, which accounts for 45-50% of the mass. The coarse model contains the the least mass, about 20%. The size spectra from gross alpha activities were bimodal with major mode in the coarse region (>1000 nm) and a minor accumulation mode in the 50-900 nm size range. These size spectra were different from the {sup 222}Rn progeny that showed a single accumulation mode in the 50- 85 nm size region. The accumulation mode in the long-lived radionuclide size spectrum was not found in previous studies in other uranium mines.

  10. Insights into Sex Chromosome Evolution and Aging from the Genome of a Short-Lived Fish.

    PubMed

    Reichwald, Kathrin; Petzold, Andreas; Koch, Philipp; Downie, Bryan R; Hartmann, Nils; Pietsch, Stefan; Baumgart, Mario; Chalopin, Domitille; Felder, Marius; Bens, Martin; Sahm, Arne; Szafranski, Karol; Taudien, Stefan; Groth, Marco; Arisi, Ivan; Weise, Anja; Bhatt, Samarth S; Sharma, Virag; Kraus, Johann M; Schmid, Florian; Priebe, Steffen; Liehr, Thomas; Görlach, Matthias; Than, Manuel E; Hiller, Michael; Kestler, Hans A; Volff, Jean-Nicolas; Schartl, Manfred; Cellerino, Alessandro; Englert, Christoph; Platzer, Matthias

    2015-12-01

    The killifish Nothobranchius furzeri is the shortest-lived vertebrate that can be bred in the laboratory. Its rapid growth, early sexual maturation, fast aging, and arrested embryonic development (diapause) make it an attractive model organism in biomedical research. Here, we report a draft sequence of its genome that allowed us to uncover an intra-species Y chromosome polymorphism representing-in real time-different stages of sex chromosome formation that display features of early mammalian XY evolution "in action." Our data suggest that gdf6Y, encoding a TGF-β family growth factor, is the master sex-determining gene in N. furzeri. Moreover, we observed genomic clustering of aging-related genes, identified genes under positive selection, and revealed significant similarities of gene expression profiles between diapause and aging, particularly for genes controlling cell cycle and translation. The annotated genome sequence is provided as an online resource (http://www.nothobranchius.info/NFINgb).

  11. Insights into Sex Chromosome Evolution and Aging from the Genome of a Short-Lived Fish.

    PubMed

    Reichwald, Kathrin; Petzold, Andreas; Koch, Philipp; Downie, Bryan R; Hartmann, Nils; Pietsch, Stefan; Baumgart, Mario; Chalopin, Domitille; Felder, Marius; Bens, Martin; Sahm, Arne; Szafranski, Karol; Taudien, Stefan; Groth, Marco; Arisi, Ivan; Weise, Anja; Bhatt, Samarth S; Sharma, Virag; Kraus, Johann M; Schmid, Florian; Priebe, Steffen; Liehr, Thomas; Görlach, Matthias; Than, Manuel E; Hiller, Michael; Kestler, Hans A; Volff, Jean-Nicolas; Schartl, Manfred; Cellerino, Alessandro; Englert, Christoph; Platzer, Matthias

    2015-12-01

    The killifish Nothobranchius furzeri is the shortest-lived vertebrate that can be bred in the laboratory. Its rapid growth, early sexual maturation, fast aging, and arrested embryonic development (diapause) make it an attractive model organism in biomedical research. Here, we report a draft sequence of its genome that allowed us to uncover an intra-species Y chromosome polymorphism representing-in real time-different stages of sex chromosome formation that display features of early mammalian XY evolution "in action." Our data suggest that gdf6Y, encoding a TGF-β family growth factor, is the master sex-determining gene in N. furzeri. Moreover, we observed genomic clustering of aging-related genes, identified genes under positive selection, and revealed significant similarities of gene expression profiles between diapause and aging, particularly for genes controlling cell cycle and translation. The annotated genome sequence is provided as an online resource (http://www.nothobranchius.info/NFINgb). PMID:26638077

  12. Short communication: Patterns of dairy consumption in free-living children and adolescents.

    PubMed

    Green, Benjamin P; Turner, Louise; Stevenson, Emma; Rumbold, Penny L S

    2015-06-01

    According to national survey data, dairy food consumption has fallen in recent years and declines further with age, especially from childhood to adolescence. Dietary surveys typically rely on retrospective dietary assessment methods and use broad age groupings (4-10 yr; 11-18 yr), making it challenging to differentiate between middle-childhood and adolescence. Consequently, there is a need to assess dairy food consumption during middle-childhood and adolescence using more robust dietary assessment tools. Therefore, the present study aimed to describe and compare patterns of dairy consumption throughout middle-childhood and adolescence. Dairy food consumption was assessed during school term-time over 4 consecutive days, including 2 weekdays and 2 weekend days, in a sample of free-living children (9-11 yr, n=40) and adolescents (15-18 yr, n=35). For children, free-living dairy intake was evaluated through parental-weighed food records, and for adolescents, a combined weighed self-reported food record and 24-h dietary recall technique was utilized. Food records were explored to determine types, amounts, and frequency of dairy food consumption, and were analyzed for differences between middle-childhood and adolescence using a between group 2×2 (age×sex) ANOVA. Descriptive data suggested that milk was the most popular dairy product consumed by both children and adolescents. Statistical analysis revealed a main effect for sex on total milk consumption (mL) and number of daily milk portions consumed. No interaction or main effect was present for any other variable. The present study indicates that independent of age, boys consumed greater amounts of milk compared with girls. Contrary to existing literature, findings suggest no difference in milk-based dairy consumption between middle-childhood and adolescence.

  13. Nanostructured recombinant cytokines: A highly stable alternative to short-lived prophylactics.

    PubMed

    Torrealba, Débora; Parra, David; Seras-Franzoso, Joaquin; Vallejos-Vidal, Eva; Yero, Daniel; Gibert, Isidre; Villaverde, Antonio; Garcia-Fruitós, Elena; Roher, Nerea

    2016-11-01

    Cytokines have been widely used as adjuvants and therapeutic agents in treatments of human diseases. Despite their recognized potential as drugs, the medical use of cytokines has considerable drawbacks, mainly related to their low stability and short half-life. Such intrinsic limitations imply the administration of high doses, often prompting toxicity, undesirable side effects and greater production costs. Here, we describe a new category of mechanically stable nanostructured cytokines (TNFα and CCL4/MIP-1β) that resist harsh physicochemical conditions in vitro (pH and temperature), while maintaining functionality. These bio-functional materials are produced in recombinant cell factories through cost-effective and fully scalable processes. Notably, we demonstrate their prophylactic potential in vivo showing they protect zebrafish from a lethal infection by Pseudomonas aeruginosa.

  14. Nanostructured recombinant cytokines: A highly stable alternative to short-lived prophylactics.

    PubMed

    Torrealba, Débora; Parra, David; Seras-Franzoso, Joaquin; Vallejos-Vidal, Eva; Yero, Daniel; Gibert, Isidre; Villaverde, Antonio; Garcia-Fruitós, Elena; Roher, Nerea

    2016-11-01

    Cytokines have been widely used as adjuvants and therapeutic agents in treatments of human diseases. Despite their recognized potential as drugs, the medical use of cytokines has considerable drawbacks, mainly related to their low stability and short half-life. Such intrinsic limitations imply the administration of high doses, often prompting toxicity, undesirable side effects and greater production costs. Here, we describe a new category of mechanically stable nanostructured cytokines (TNFα and CCL4/MIP-1β) that resist harsh physicochemical conditions in vitro (pH and temperature), while maintaining functionality. These bio-functional materials are produced in recombinant cell factories through cost-effective and fully scalable processes. Notably, we demonstrate their prophylactic potential in vivo showing they protect zebrafish from a lethal infection by Pseudomonas aeruginosa. PMID:27614162

  15. Short Lived Climate Pollutants cause a Long Lived Effect on Sea-level Rise: Analyzing climate metrics for sea-level rise

    NASA Astrophysics Data System (ADS)

    Sterner, E.; Johansson, D. J.

    2013-12-01

    Climate change depends on the increase of several different atmospheric pollutants. While long term global warming will be determined mainly by carbon dioxide, warming in the next few decades will depend to a large extent on short lived climate pollutants (SLCP). Reducing emissions of SLCPs could contribute to lower the global mean surface temperature by 0.5 °C already by 2050 (Shindell et al. 2012). Furthermore, the warming effect of one of the most potent SLCPs, black carbon (BC), may have been underestimated in the past. Bond et al. (2013) presents a new best estimate of the total BC radiative forcing (RF) of 1.1 W/m2 (90 % uncertainty bounds of 0.17 to 2.1 W/m2) since the beginning of the industrial era. BC is however never emitted alone and cooling aerosols from the same sources offset a majority of this RF. In the wake of calls for mitigation of SLCPs it is important to study other aspects of the climate effect of SLCPs. One key impact of climate change is sea-level rise (SLR). In a recent study, the effect of SLCP mitigation scenarios on SLR is examined. Hu et al (2013) find a substantial effect on SLR from mitigating SLCPs sharply, reducing SLR by 22-42% by 2100. We choose a different approach focusing on emission pulses and analyse a metric based on sea level rise so as to further enlighten the SLR consequences of SLCPs. We want in particular to understand the time dynamics of SLR impacts caused by SLCPs compared to other greenhouse gases. The most commonly used physical based metrics are GWP and GTP. We propose and evaluate an additional metric: The global sea-level rise potential (GSP). The GSP is defined as the sea level rise after a time horizon caused by an emissions pulse of a forcer to the sea level rise after a time horizon caused by an emissions pulse of a CO2. GSP is evaluated and compared to GWP and GTP using a set of climate forcers chosen to cover the whole scale of atmospheric perturbation life times (BC, CH4, N2O, CO2 and SF6). The study

  16. The likely presence of nuclides with short half-lives in HD965 and HD101065 (Przybylski's Star)

    NASA Astrophysics Data System (ADS)

    Cowley, C. R.; Bidelman, W. P.; Hubrig, S.; Mathys, G.; Bord, D. J.

    2003-12-01

    Two chemical elements lighter than bismuth have no isotopes with half-lives longer than 5 million years: the 4d-element technetium and the lanthanide promethium. While 98Tc has a half-life of 4.2 106 years, the longest-lived isotope of Pm, 145Pm, has a half-life of only 17.7 years. The presence of either of these elements in upper main sequence stars would pose a serious problem for our understanding of the chemistry of these stars. It is now generally accepted that the chemical anomalies of numerous subtypes of peculiar B, A, and F stars is a superficial phenomenon caused by chemical separation under the competing influences of radiation pressure and gravity. This theory would have to be supplemented should the presence of these unstable species be confirmed. There is substantial evidence to support the presence of PmI and/or II, and TcI, in HD101065, and PmI and/or II in HD965. HD101065 is a notorious object, well known for the strength of its rare-earth spectra relative to the iron group (see url below for data and references). Hubrig, et al. (ASP Conf. Ser. 279, ed. C. A. Tout and W. Van Hamme, p. 365) noted the similarity of HD965 toPrzybylski's star. Identifications of Tc and Pm in these stars are based on wavelength coincidence statistics (WCS Cowley and Hensberge, ApJ 244. 252. 1081)and traditional line-by-line examinations taking into account laboratory intensities, excitation potentials, and wavelength agreement. Wavelength measurements are available at http://www.astro.lsa.umich.edu/users/cowley/. The highest significances are obtained for HD965 and a list of strong PmI and II from the NIST site (Sansonetti and Martin http://physics.nist.gov/PhysRefData/Handbook/index.html). We found 14 of 39 lines within ± 0.02Å, which is a 99.9% confident result. Various tests for PmI and II in HD101065 lead to 99% confidence or better. WCS yields 95-99% confidence for TcI in HD101065.

  17. Comparison of distribution and activity of nanoparticles with short interfering DNA (Dbait) in various living systems.

    PubMed

    Berthault, N; Maury, B; Agrario, C; Herbette, A; Sun, J-S; Peyrieras, N; Dutreix, M

    2011-10-01

    Introducing small DNA molecules (Dbait) impairs the repair of damaged chromosomes and provides a new method for enhancing the efficiency of radiotherapy in radio-resistant tumors. The radiosensitizing activity is dependent upon the efficient delivery of Dbait molecules into the tumor cells. Different strategies have been compared, to improve this key step. We developed a pipeline of assays to select the most efficient nanoparticles and administration protocols before preclinical assays: (i) molecular analyses of complexes formed with Dbait molecules, (ii) cellular tests for Dbait uptake and activity, (iii) live zebrafish embryo confocal microscopy monitoring for in vivo distribution and biological activity of the nanoparticles and (iv) tumor growth and survival measurement on mice with xenografted tumors. Two classes of nanoparticles were compared, polycationic polymers with linear or branched polyethylenimine (PEI) and covalently attached cholesterol (coDbait). The most efficient Dbait transfection was observed with linear PEI complexes, in vitro and in vivo. Doses of coDbait ten-fold higher than PEI/Dbait nanoparticles, and pretreatment with chloroquine, were required to obtain the same antitumoral effect on xenografted melanoma. However, with a 22-fold lower 'efficacy dose/toxicity dose' ratio as compared with Dbait/PEI, coDbait was selected for clinical trials. PMID:21799529

  18. Isotopic and physiological responses during short-term acclimation to atmospheric CO2 concentration in Pinus nigra.

    NASA Astrophysics Data System (ADS)

    Maseyk, Kadmiel; Biron, Philippe; Richard, Patricia; Canal, Laurent; Bariac, Thierry

    2010-05-01

    The response of plants to increasing atmospheric CO2 concentrations will have an important influence on biogeochemical cycles in the future. These responses are physiologically driven, but have important feedbacks to water and nutrient cycles as the plants adjust photosynthetic activity within the constraints of these other cycles. Leaf scale manipulations of CO2 concentration provide us with a wealth of information on the short-term, biochemical response of leaf photosynthesis, but these responses do not translate to whole plant responses under sustained growth at higher CO2 concentrations, as has been evidenced by free air enrichment studies. Here we report on a study into whole plant responses to CO2 concentration using a new, 10m3 isotope-biogeochemistry growth chamber housing small (1.5m) potted Pinus nigra trees under controlled conditions. This chamber is capable of controlling the climatic and CO2 conditions and designed for sampling biogeochemical pools for isotopic analysis with minimal disturbance to the system. The trees were maintained at 20°C and 50-60% RH, and at three CO2 concentrations (380 ppm, 500 ppm, 800 ppm) for ~10 days each to explore whole-plant physiological acclimation responses with other factors being constant (i.e. soil nutrient and water status). New steady-state conditions were reached after 5-6 days, and samples of chamber air and transpired water vapour were collected during a diurnal period at the end of the treatment period and analysed for their isotopic (13C, 18O) composition. Transpiration rate and 18O composition were relatively steady over the photoperiod, while the 18O of air CO2 typically displayed a 5-10 permil decline. The 13C of air CO2 varied by 2-3 permil over the day, but did not show a consistent pattern between treatments. There was a highly correlated enrichment in the end-of-day values of atmospheric CO2 18O (by ~3 permil) and 13C (by ~2 permil) across the three CO2 concentrations. Transpiration trends were

  19. Measurement of the body composition of living gray seals by hydrogen isotope dilution

    SciTech Connect

    Reilly, J.J.; Fedak, M.A. )

    1990-09-01

    The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a two-step model that involves measurement of total body water (TBW) by {sup 2}H or {sup 3}H dilution and application of predictive relationships between body components and TBW that were derived empirically by slaughter chemical analysis. TBW was overestimated by both {sup 2}HHO and {sup 3}HHO dilution; mean overestimates were 2.8 +/- 0.9% (SE) with 2H and 4.0 +/- 0.6% with {sup 3}H. The relationships for prediction of total body fat (TBF), protein (TBP), gross energy (TBGE), and ash (TBA) were as follows: %TBF = 105.1 - 1.47 (%TBW); %TBP = 0.42 (%TBW) - 4.75; TBGE (MJ) = 40.8 (mass in kg) - 48.5 (TBW in kg) - 0.4; and TBA (kg) = 0.1 - 0.008 (mass in kg) + 0.05 (TBW in kg). These relationships are applicable to gray seals of both sexes over a wide range of age and body conditions, and they predict the body composition of gray seals more accurately than the predictive equations derived from ringed seals (Pusa hispida) and from the equation of Pace and Rathbun, which has been reported to be generally applicable to mammals.

  20. Balancing Short- and Long-lived Climate Pollutant Mitigation: Clearer Metrics are Critical

    NASA Astrophysics Data System (ADS)

    Ocko, I.; Hamburg, S.; Pacala, S. W.

    2015-12-01

    We propose a new standard for reporting Global Warming Potentials (GWPs) that is central to climate policy debates and decision-making. GWPs are an essential element of policy analysis and policymaking, and are even built into legal structures that regulate "carbon dioxide equivalents." However, the current reporting convention is misleading because it hides the divergence between short and long-term interests inside a single timescale. We propose using two timescales everywhere, as an inseparable pair. This makes explicit one of the principal issues in climate policy: the temporal tradeoffs of benefits among actions that reduce emissions of a suite of climate pollutants. Policymakers often treat GWPs as if they were a value-neutral technocratic measure, while in fact the choice of timescales, at the heart of the GWP, is central to the political battles over climate policy. At its most basic, cutting emissions of pollutants with different radiative properties and atmospheric lifetimes yields climate benefits that vary in the near- and long-term. Battles such as that between coal and natural gas rest on this distinction. The most common form of GWP is based on a 100 year time integral, but this timescale conceals near-term impacts. On the other hand, opting instead for a 20 year time integral ignores climate impacts after 20 years. A distinguished list of scientists and economists has attempted to come up with improved metrics that incorporate the range of timescales into a single value. Our proposal abandons this quest. There is no "right" answer to the underlying dispute, but there is a right answer for policy analysis: use two time constants together, similar to the way that systolic and diastolic blood pressures, latitude and longitude, and city and highway gas mileage are reported together. This strategy will provide much needed clarification to myriad climate change solution-related decisions.

  1. Calcium influx through TRP channels induced by short-lived reactive species in plasma-irradiated solution

    PubMed Central

    Sasaki, Shota; Kanzaki, Makoto; Kaneko, Toshiro

    2016-01-01

    Non-equilibrium helium atmospheric-pressure plasma (He-APP), which allows for a strong non-equilibrium chemical reaction of O2 and N2 in ambient air, uniquely produces multiple extremely reactive products, such as reactive oxygen species (ROS), in plasma-irradiated solution. We herein show that relatively short-lived unclassified reactive species (i.e., deactivated within approximately 10 min) generated by the He-APP irradiation can trigger physiologically relevant Ca2+ influx through ruthenium red- and SKF 96365-sensitive Ca2+-permeable channel(s), possibly transient receptor potential channel family member(s). Our results provide novel insight into understanding of the interactions between cells and plasmas and the mechanism by which cells detect plasma-induced chemically reactive species, in addition to facilitating development of plasma applications in medicine. PMID:27169489

  2. Rituximab ameliorates anti-N-methyl-D-aspartate receptor encephalitis by removal of short-lived plasmablasts.

    PubMed

    Hachiya, Yasuo; Uruha, Akinori; Kasai-Yoshida, Emi; Shimoda, Konomi; Satoh-Shirai, Ikuko; Kumada, Satoko; Kurihara, Eiji; Suzuki, Kotoko; Ohba, Atsuko; Hamano, Shin-ichiro; Sakuma, Hiroshi

    2013-12-15

    We measured anti-N-methyl-D-aspartate receptor (NMDAR) autoantibody levels and assessed B cell subsets using multicolor flow cytometry of peripheral blood mononuclear cells (PBMCs) from a recurrent anti-NMDAR encephalitis case to evaluate the effectiveness of rituximab treatment. Rituximab depleted CD20(+) fractions of naïve and memory B cell subsets and reduced the number of CD20(-) plasmablasts. This study suggests that short-lived plasmablasts are removed by rituximab-induced depletion of the CD20(+) B cell population. Increased numbers of plasmablasts in PBMCs may be a candidate predictive factor for unfavorable prognosis of anti-NMDAR encephalitis and an indication of when to commence second-line immunotherapy. PMID:24183642

  3. Identifying and quantifying short-lived fission products from thermal fission of HEU using portable HPGe detectors

    SciTech Connect

    Pierson, Bruce D.; Finn, Erin C.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Kephart, Rosara F.; Metz, Lori A.

    2013-03-01

    Due to the emerging potential for trafficking of special nuclear material, research programs are investigating current capabilities of commercially available portable gamma ray detection systems. Presented in this paper are the results of three different portable high-purity germanium (HPGe) detectors used to identify short-lived fission products generated from thermal neutron interrogation of small samples of highly enriched uranium. Samples were irradiated at the Washington State University (WSU) Nuclear Radiation Center’s 1MW TRIGA reactor. The three portable, HPGe detectors used were the ORTEC MicroDetective, the ORTEC Detective, and the Canberra Falcon. Canberra’s GENIE-2000 software was used to analyze the spectral data collected from each detector. Ultimately, these three portable detectors were able to identify a large range of fission products showing potential for material discrimination.

  4. Using Atmospheric Dispersion Theory to Inform the Design of a Short-lived Radioactive Particle Release Experiment.

    PubMed

    Rishel, Jeremy P; Keillor, Martin E; Arrigo, Leah M; Baciak, James E; Detwiler, Rebecca S; Kernan, Warnick J; Kirkham, Randy R; Milbrath, Brian D; Seifert, Allen; Seifert, Carolyn E; Smart, John E

    2016-05-01

    Atmospheric dispersion theory can be used to predict ground deposition of particulates downwind of a radionuclide release. This paper uses standard formulations found in Gaussian plume models to inform the design of an experimental release of short-lived radioactive particles into the atmosphere. Specifically, a source depletion algorithm is used to determine the optimum particle size and release height that maximizes the near-field deposition while minimizing both the required source activity and the fraction of activity lost to long-distance transport. The purpose of the release is to provide a realistic deposition pattern that might be observed downwind of a small-scale vent from an underground nuclear explosion. The deposition field will be used, in part, to study several techniques of gamma radiation survey and spectrometry that could be used by an On-Site Inspection team investigating such an event. PMID:27023039

  5. Short-lived halocarbons efficient at influencing climate through ozone loss in the upper troposphere-lower stratosphere

    NASA Astrophysics Data System (ADS)

    Hossaini, Ryan; Chipperfield, Martyn; Montzka, Steven; Rap, Alex; Dhomse, Sandip; Feng, Wuhu

    2015-04-01

    Halogenated very short-lived substances (VSLS) of both natural and anthropogenic origin are a significant source of atmospheric bromine, chlorine and iodine. Due to relatively short atmospheric lifetimes (typically <6 months), VSLS breakdown in the upper troposphere-lower stratosphere (UTLS), where ozone perturbations drive a disproportionately large climate impact compared to other altitudes. Here we present chemical transport model simulations that quantify VSLS-driven ozone loss in the UTLS and infer the climate relevance of these ozone perturbations using a radiative transfer model. Our results indicate that through their impact on UTLS ozone, VSLS are efficient at influencing climate. We calculate a whole atmosphere global mean radiative effect (RE) of -0.20 (-0.16 to -0.23) Wm-2 from natural and anthropogenic VSLS-driven ozone loss, including a tropospheric contribution of -0.12 Wm-2. In the stratosphere, the RE due to ozone loss from natural bromine-containing VSLS (e.g. CHBr3, CH2Br2) is almost half of that from long-lived anthropogenic compounds (e.g. CFCs) and normalized by equivalent chlorine is ~4 times larger. We show that the anthropogenic chlorine-containing VSLS, not regulated by the Montreal Protocol, also contribute to ozone loss in the UTLS and that the atmospheric concentration of dichloromethane (CH2Cl2), the most abundant of these, is increasing rapidly. Finally, we present evidence that VSLS have made a small yet previously unrecognized contribution to the ozone-driven radiative forcing of climate since pre-industrial times of -0.02 (-0.01 to -0.03) Wm-2. Given the climate leverage that VSLS possess, future increases to their emissions, either through continued industrial or altered natural processes, may be important for future climate forcing.

  6. Thyroid cancer in the Marshallese: relative risk of short-lived internal emitters and external radiation exposure

    SciTech Connect

    Lessard, E.T.; Brill, A.B.; Adams, W.H.

    1985-01-01

    In a study of the comparative effects of internal versus external irradiation of the thyroid in young people, we determined that the dose from internal irradiation of the thyroid with short-lived internal emitters produced several times less thyroid cancer than did the same dose of radiation given externally. We determined this finding for a group of 85 Marshall Islands children, who were less than 10 years of age at the time of exposure and who were accidentially exposed to internal and external thyroid radiation at an average level of 1400 rad. The external risk coefficient ranged between 2.5 and 4.9 cancers per million person-rad-years at risk, and thus, from our computations, the internal risk coefficient for the Marshallese children was estimated to range between 1.0 and 1.4 cancers per million person-rad-years at risk. In contrast, for individual more than 10 years of age at the time of exposure, the dose from internal irradiation of the thyroid with short-lived internal emitters produced several times more thyroid cancer than did the same dose of radiation given externally. The external risk coefficients for the older age groups were reported in the literature to be in the range of 1.0 to 3.3 cancers per million person-rad-years-at risk. We computed internal risk coefficients of 3.3 to 8.1 cancers per million person-rad-years at risk for adolescent and adult groups. This higher sensitivity to cancer induction in the exposed adolescents and adults, is different from that seen in other exposed groups. 14 refs., 8 tabs.

  7. Evolution of the Galaxy and the Birth of the Solar System: The Short-Lived Nuclides Connection

    NASA Astrophysics Data System (ADS)

    Sahijpal, S.

    2014-06-01

    An attempt is made, probably for the first time, to understand the origin of the solar system in context with the evolution of the galaxy as a natural consequence of the birth of several generations of stellar clusters. The galaxy is numerically simulated to deduce the inventories of the short-lived nuclides, 26Al, 36Cl, 41Ca, 53Mn and 60Fe, from the stellar nucleosynthetic contributions of the various stellar clusters using an N-body simulation with updated prescriptions of the astrophysical processes. The galaxy is evolved by considering the discreteness associated with the stellar clusters and individual stars. We estimate the steady state abundance of the radionuclides around 4.56 billion years ago at the time of formation of the solar system. Further, we also estimate the present 26Al/27Al and 60Fe/56Fe of the interstellar medium that match within a factor of two with the observed estimates. In contrary to the conventional Galactic Chemical Evolution (GCE) model, the present adopted numerical approach provides a natural framework to understand the astrophysical environment related with the origin of the solar system. We deduce the nature of the two stellar clusters; the one that formed and evolved prior to the solar system formation, and the other within which the solar system that was probably formed. The former could have contributed to the short-lived nuclides 129I and 53Mn, whereas, the supernova associated with the most massive star in the latter contributed 26Al and 60Fe to the solar system. The analysis was performed with the revised solar metallicity of 0.014.

  8. Formation of the Short-lived Radionuclide 36Cl in the Protoplanetary Disk During Late-stage Irradiation of a Volatile-rich Reservoir

    NASA Astrophysics Data System (ADS)

    Jacobsen, Benjamin; Matzel, Jennifer; Hutcheon, Ian D.; Krot, Alexander N.; Yin, Qing-Zhu; Nagashima, Kazuhide; Ramon, Erick C.; Weber, Peter K.; Ishii, Hope A.; Ciesla, Fred J.

    2011-04-01

    Short-lived radionuclides (SLRs) in the early solar system provide fundamental insight into protoplanetary disk evolution. We measured the 36Cl-36S-isotope abundance in wadalite (<15 μm), a secondary chlorine-bearing mineral found in calcium-aluminum-rich inclusions (CAIs) in the Allende CV chondrite, to decipher the origin of the SLR 36Cl (τ 1/2 ~ 3 × 105 yr) in the early solar system. Its presence, initial abundance, and the noticeable decoupling from 26Al raise serious questions about the origin of SLRs. The inferred initial 36Cl abundance for wadalite, corresponding to a 36Cl/35Cl ratio of (1.81 ± 0.13) × 10-5, is the highest 36Cl abundance ever reported in any early solar system material. The high level of 36Cl in wadalite and the absence of 26Al (26Al/27Al <= 3.9 × 10-6) in co-existing grossular (1) unequivocally support the production of 36Cl by late-stage solar energetic particle irradiation in the protoplanetary disk and (2) indicates that the production of 36Cl, recorded by wadalite, is unrelated to the origin of 26Al and other SLRs (10Be, 53Mn) recorded by primary minerals of CAIs and chondrules. We infer that 36Cl was largely produced by irradiation of a volatile-rich reservoir in an optically thin protoplanetary disk adjacent to the region in which the CV chondrite parent asteroid accreted while the Sun was a weak T Tauri star. Subsequently, 36Cl accreted into the Allende CV chondrite together with condensed water ices.

  9. FORMATION OF THE SHORT-LIVED RADIONUCLIDE {sup 36}Cl IN THE PROTOPLANETARY DISK DURING LATE-STAGE IRRADIATION OF A VOLATILE-RICH RESERVOIR

    SciTech Connect

    Jacobsen, Benjamin; Yin Qingzhu; Matzel, Jennifer; Hutcheon, Ian D.; Ramon, Erick C.; Weber, Peter K.; Krot, Alexander N.; Nagashima, Kazuhide; Ishii, Hope A.; Ciesla, Fred J.

    2011-04-20

    Short-lived radionuclides (SLRs) in the early solar system provide fundamental insight into protoplanetary disk evolution. We measured the {sup 36}Cl-{sup 36}S-isotope abundance in wadalite (<15 {mu}m), a secondary chlorine-bearing mineral found in calcium-aluminum-rich inclusions (CAIs) in the Allende CV chondrite, to decipher the origin of the SLR {sup 36}Cl ({tau}{sub 1/2} {approx} 3 x 10{sup 5} yr) in the early solar system. Its presence, initial abundance, and the noticeable decoupling from {sup 26}Al raise serious questions about the origin of SLRs. The inferred initial {sup 36}Cl abundance for wadalite, corresponding to a {sup 36}Cl/{sup 35}Cl ratio of (1.81 {+-} 0.13) x 10{sup -5}, is the highest {sup 36}Cl abundance ever reported in any early solar system material. The high level of {sup 36}Cl in wadalite and the absence of {sup 26}Al ({sup 26}Al/{sup 27}Al {<=} 3.9 x 10{sup -6}) in co-existing grossular (1) unequivocally support the production of {sup 36}Cl by late-stage solar energetic particle irradiation in the protoplanetary disk and (2) indicates that the production of {sup 36}Cl, recorded by wadalite, is unrelated to the origin of {sup 26}Al and other SLRs ({sup 10}Be, {sup 53}Mn) recorded by primary minerals of CAIs and chondrules. We infer that {sup 36}Cl was largely produced by irradiation of a volatile-rich reservoir in an optically thin protoplanetary disk adjacent to the region in which the CV chondrite parent asteroid accreted while the Sun was a weak T Tauri star. Subsequently, {sup 36}Cl accreted into the Allende CV chondrite together with condensed water ices.

  10. TRIGGERING COLLAPSE OF THE PRESOLAR DENSE CLOUD CORE AND INJECTING SHORT-LIVED RADIOISOTOPES WITH A SHOCK WAVE. II. VARIED SHOCK WAVE AND CLOUD CORE PARAMETERS

    SciTech Connect

    Boss, Alan P.; Keiser, Sandra A. E-mail: keiser@dtm.ciw.edu

    2013-06-10

    A variety of stellar sources have been proposed for the origin of the short-lived radioisotopes that existed at the time of the formation of the earliest solar system solids, including Type II supernovae (SNe), asymptotic giant branch (AGB) and super-AGB stars, and Wolf-Rayet star winds. Our previous adaptive mesh hydrodynamics models with the FLASH2.5 code have shown which combinations of shock wave parameters are able to simultaneously trigger the gravitational collapse of a target dense cloud core and inject significant amounts of shock wave gas and dust, showing that thin SN shocks may be uniquely suited for the task. However, recent meteoritical studies have weakened the case for a direct SN injection to the presolar cloud, motivating us to re-examine a wider range of shock wave and cloud core parameters, including rotation, in order to better estimate the injection efficiencies for a variety of stellar sources. We find that SN shocks remain as the most promising stellar source, though planetary nebulae resulting from AGB star evolution cannot be conclusively ruled out. Wolf-Rayet (WR) star winds, however, are likely to lead to cloud core shredding, rather than to collapse. Injection efficiencies can be increased when the cloud is rotating about an axis aligned with the direction of the shock wave, by as much as a factor of {approx}10. The amount of gas and dust accreted from the post-shock wind can exceed that injected from the shock wave, with implications for the isotopic abundances expected for a SN source.

  11. Fecal cortisol levels predict breeding but not survival of females in the short-lived rodent, Octodon degus.

    PubMed

    Ebensperger, Luis A; Tapia, Diego; Ramírez-Estrada, Juan; León, Cecilia; Soto-Gamboa, Mauricio; Hayes, Loren D

    2013-06-01

    The cort-adaptation hypothesis indicates that an association between glucocorticoid (cort) levels and fitness may vary with the extent to which reproduction or breeding effort is a major determinant of cort levels. Support for a context dependent association between cort and fitness comes mostly from relatively long-lived, bird species. We tested the hypothesis that there are gender and context (life-history) specific cort-fitness relationships in degus, a short-lived and generally semelparous social rodent. In particular, we used demographical records on a natural population to estimate adult survival through seasons and years and linked that to records of baseline cort (based on fecal cortisol metabolites). We found no evidence for a direct relationship between baseline cort and adult survival across seasons, and this lack of association was recorded irrespective of sex and life history stage. Yet, cort levels during early lactation predicted the probability that females produce a second litter during the same breeding season, supporting a connection between baseline cort levels and breeding effort. Overall, the differential effects of cort on survival and breeding supported that the extent of cort-fitness relationships depends on the fitness component examined.

  12. Short-term outcomes for obese live kidney donors and their recipients1,2,3,4,5,6

    PubMed Central

    Reese, Peter P.; Feldman, Harold I.; Asch, David A.; Thomasson, Arwin; Shults, Justine; Bloom, Roy D.

    2009-01-01

    Background Given the association between obesity and kidney disease, transplant professionals have debated the appropriateness of accepting obese live kidney donors. We hypothesized that compared to normal weight donors, donors with elevated body mass index (BMI) would have 1) more peri-operative re-admissions and re-operations, and 2) a greater rise in blood pressure, greater percent rise in serum creatinine, and a greater loss of estimated glomerular filtration rate (eGFR) following nephrectomy. Methods Retrospective cohort study using Organ Procurement and Transplantation Network data on live donors who donated kidneys from 7/1/2004 –12/31/2005. Results 9319 live donor kidney transplants were performed. After eliminating donors with missing BMI data, 5304 donors were analyzed, among whom 2108 (40.0%) were overweight (25 ≤ BMI < 30), 944 (17.8%) were obese (30 ≤ BMI < 35), and 250 (4.7%) were very obese (BMI>=35). Re-admission and re-operation rates did not differ across donor BMI categories. At baseline and at 6 months after nephrectomy, higher BMI was associated with higher blood pressure (p<0.01), but changes in systolic blood pressure from baseline were similar across BMI categories (p=0.40). At six months, decline in eGFR from baseline (p=0.63) and percent change in creatinine (p=0.11) did not differ significantly across groups. Delayed graft function was more common among recipients of kidneys from very obese donors (OR 2.16, CI 1.20 – 3.89, p=0.01), but the rates of recipient allograft failure and mortality across donor BMI groups were similar. Conclusion Short-term follow-up data show good outcomes for donors with elevated BMI and their recipients. PMID:19741463

  13. Targeted alpha therapy using short-lived alpha-particles and the promise of nanobodies as targeting vehicle

    PubMed Central

    Dekempeneer, Yana; Keyaerts, Marleen; Krasniqi, Ahmet; Puttemans, Janik; Muyldermans, Serge; Lahoutte, Tony; D’huyvetter, Matthias; Devoogdt, Nick

    2016-01-01

    ABSTRACT Introduction: The combination of a targeted biomolecule that specifically defines the target and a radionuclide that delivers a cytotoxic payload offers a specific way to destroy cancer cells. Targeted radionuclide therapy (TRNT) aims to deliver cytotoxic radiation to cancer cells and causes minimal toxicity to surrounding healthy tissues. Recent advances using α-particle radiation emphasizes their potential to generate radiation in a highly localized and toxic manner because of their high level of ionization and short range in tissue. Areas covered: We review the importance of targeted alpha therapy (TAT) and focus on nanobodies as potential beneficial vehicles. In recent years, nanobodies have been evaluated intensively as unique antigen-specific vehicles for molecular imaging and TRNT. Expert opinion: We expect that the efficient targeting capacity and fast clearance of nanobodies offer a high potential for TAT. More particularly, we argue that the nanobodies’ pharmacokinetic properties match perfectly with the interesting decay properties of the short-lived α-particle emitting radionuclides Astatine-211 and Bismuth-213 and offer an interesting treatment option particularly for micrometastatic cancer and residual disease. PMID:27145158

  14. Inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS for isotope analysis of long-lived radionuclides

    NASA Astrophysics Data System (ADS)

    Becker, J. Sabine

    2005-04-01

    For a few years now inductively coupled plasma mass spectrometry has been increasingly used for precise and accurate determination of isotope ratios of long-lived radionuclides at the trace and ultratrace level due to its excellent sensitivity, good precision and accuracy. At present, ICP-MS and also laser ablation ICP-MS are applied as powerful analytical techniques in different fields such as the characterization of nuclear materials, recycled and by-products (e.g., spent nuclear fuel or depleted uranium ammunitions), radioactive waste control, in environmental monitoring and in bioassay measurements, in health control, in geochemistry and geochronology. Especially double-focusing sector field ICP mass spectrometers with single ion detector or with multiple ion collector device have been used for the precise determination of long-lived radionuclides isotope ratios at very low concentration levels. Progress has been achieved by the combination of ultrasensitive mass spectrometric techniques with effective separation and enrichment procedures in order to improve detection limits or by the introduction of the collision cell in ICP-MS for reducing disturbing interfering ions (e.g., of 129Xe+ for the determination of 129I). This review describes the state of the art and the progress of ICP-MS and laser ablation ICP-MS for isotope ratio measurements of long-lived radionuclides in different sample types, especially in the main application fields of characterization of nuclear and radioactive waste material, environmental research and health controls.

  15. Photonuclear Production of Medical Isotopes

    NASA Astrophysics Data System (ADS)

    Weinandt, Nick

    2011-10-01

    Every year, more than 20 million people in the United States receive a nuclear medicine procedure. Many of the isotopes needed for these procedures are under-produced. Suppliers of the isotopes are usually located outside the United States, which presents a problem when the desired isotopes have short half-lives. Linear accelerators were investigated as a possible method of meeting isotope demand. Linear accelerators are cheaper, safer, and have lower decommissioning costs compared to nuclear reactors. By using (γ,p) reactions, the desired isotope can be separated from the target material due to the different chemical nature of each isotope. Isotopes investigated were Cu-67, In-111, and Lu-111. Using the results the photon flux Monte Carlo simulations, the expected activity of isotopes can be calculated. After samples were irradiated, a high purity germanium detector and signal processing apparatus were used to count the samples. The activity at the time of irradiation stop was then calculated. The uses of medical isotopes will also be presented. Thanks to Idaho State University, the Idaho Accelerator Center, and the National Science Foundation for supporting the research.

  16. Modeling of radon and its short-lived decay products emanating from tap water used inside a house: dose to adult members of the public.

    PubMed

    Ouabi, H

    2009-01-01

    Radon concentrations are measured in the tap water collected in different areas in Marrakech (Morocco) by using liquid scintillation techniques. The concentrations due to radon and its short-lived decay products emanating from the tap water used inside different compartments of the house were determined. Alpha activities due to the (218)Po and (214)Po short-lived radon decay products were evaluated in various compartments of the respiratory tract of adult members of the public. The committed equivalent doses due to the (218)Po and (214)Po short-lived progeny of radon were evaluated in different tissues of the respiratory tract by the frequencies of using the various parts of the house. PMID:18789711

  17. Folate bioavailability from foods rich in folates assessed in a short term human study using stable isotope dilution assays.

    PubMed

    Mönch, Sabine; Netzel, Michael; Netzel, Gabriele; Ott, Undine; Frank, Thomas; Rychlik, Michael

    2015-01-01

    Different sources of folate may have different bioavailability and hence may impact the standard definition of folate equivalents. In order to examine this, a short term human study was undertaken to evaluate the relative native folate bioavailabilities from spinach, Camembert cheese and wheat germs compared to pteroylmonoglutamic acid as the reference dose. The study had a single-centre, randomised, four-treatment, four-period, four-sequence, cross-over design, i.e. the four (food) items to be tested (referred to as treatments) were administered in sequences according to the Latin square, so that each experimental treatment occurred only once within each sequence and once within each study period. Each of the 24 subjects received the four experimental items separated by a 14-day equilibrium phase and received a pteroylmonoglutamic acid supplement for 14 days before the first testing and between the testings for saturation of body pools. Folates in test foods, plasma and urine samples were determined by stable isotope dilution assays, and in urine and plasma, the concentrations of 5-methyltetrahydrofolate were evaluated. Standard non-compartmental methods were applied to determine the biokinetic parameters C(max), t(max) and AUC from baseline corrected 5-methyltetrahydrofolate concentrations within the interval from 0 to 12 hours. The variability of AUC and C(max) was moderate for spinach and oral solution of pteroylmonoglutamic acid but high for Camembert cheese and very high for wheat germs. The median t(max) was lowest for spinach, though t(max) showed a high variability among all treatments. When comparing the ratio estimates of AUC and C(max) for the different test foods, highest bioavailability was found for spinach followed by that for wheat germs and Camembert cheese. The results underline the dependence of folate bioavailability on the type of food ingested. Therefore, the general assumption of 50% bioavailability as the rationale behind the definition of

  18. Inverse Ubbelohde effect in the short hydrogen bond of photosystem II: Relation between H/D isotope effect and symmetry in potential energy profile.

    PubMed

    Kanematsu, Yusuke; Tachikawa, Masanori; Takano, Yu

    2016-09-01

    The short hydrogen bond between tyrosine Yz and D1-His190 of photosystem II (PSII) was investigated using multicomponent quantum mechanics, where the quantum fluctuation of a hydrogen nucleus was incorporated into electronic structure calculation. Our computation demonstrated that the deuteration for hydrogen in the short hydrogen bond of PSII led to the reduction of the O…N distance. It indicated an inverse Ubbelohde effect typically recognized in strong and symmetric hydrogen-bonding clusters such as FHF(-) and H3O2-. We confirmed that the relation between the geometric isotope effect and the symmetry of the potential energy profile of FHF(-) was reasonably agreed with that of PSII. According to this agreement, the short hydrogen bond in PSII can be regarded as a short strong hydrogen bond. © 2016 Wiley Periodicals, Inc.

  19. Identifying emission source regions and transport pathways of very short-lived halogens over the Western Pacific

    NASA Astrophysics Data System (ADS)

    Butler, Robyn; Palmer, Paul; Feng, Liang; Harris, Neil; Carpenter, Lucy; Andrews, Steve; Atlas, Elliot; Salawitch, Ross; Pan, Laura; Donets, Valeria; Schauffler, Sue

    2016-04-01

    Deep, tropical convective systems lead to the rapid transport of very short-lived halogenated substances (VSLS) to the tropical tropopause layer (TTL). They are then subsequently transported to the lower stratosphere and chemically broken down to release the constituent halogens that catalytically destroy ozone. Although the oceans are known to represent the largest VSLS source, the relative contribution of geographical regions through emission and transport is poorly understood. We present a study on the origin and variability of VSLS over the Western Pacific using data collected during the CAST and CONTRAST measurement campaigns, January/February 2014. We have developed a version of the GEOS-Chem atmospheric chemistry transport model that tags emissions of bromoform (CHBr3) and dibromomethane (CH2Br2) from different geographical regions. We focus the source regions on land and (coastal and open) oceanic emissions. We have also developed a similar tagged method to calculate the physical age of air parcels from these source regions to quantify the speed of vertical transport. Using this approach we have quantified relative contributions of source regions and show that open oceanic emission regions are the dominant source of VSLS gases during the measurement campaigns. By looking at variability over the region, we see that this is caused by direct convection of marine emissions over the open ocean leading to increased contribution to CHBr3 and CH2Br2 mixing ratios from this source region. Open oceanic emissions are transported to the TTL within the average atmospheric lifetime of CHBr3, the shorter lived species, whereas emissions from coastal ocean and land source regions have an older physical age at the TTL. The relative contribution from island land masses in the campaign region have no impact over the vertical profile but does impact local mixing ratios.

  20. The adaptive significance of temperature-dependent sex determination: experimental tests with a short-lived lizard.

    PubMed

    Warner, Daniel A; Shine, Richard

    2005-10-01

    Why is the sex of many reptiles determined by the temperatures that these animals experience during embryogenesis, rather than by their genes? The Charnov-Bull model suggests that temperature-dependent sex determination (TSD) can enhance maternal fitness relative to genotypic sex determination (GSD) if offspring traits affect fitness differently for sons versus daughters and nest temperatures either determine or predict those offspring traits. Although potential pathways for such effects have attracted much speculation, empirical tests largely have been precluded by logistical constraints (i.e., long life spans and late maturation of most TSD reptiles). We experimentally tested four differential fitness models within the Charnov-Bull framework, using a short-lived, early-maturing Australian lizard (Amphibolurus muricatus) with TSD. Eggs from wild-caught females were incubated at a range of thermal regimes, and the resultant hatchlings raised in large outdoor enclosures. We applied an aromatase inhibitor to half the eggs to override thermal effects on sex determination, thus decoupling sex and incubation temperature. Based on relationships between incubation temperatures, hatching dates, morphology, growth, and survival of hatchlings in their first season, we were able to reject three of the four differential fitness models. First, matching offspring sex to egg size was not plausible because the relationship between egg (offspring) size and fitness was similar in the two sexes. Second, sex differences in optimal incubation temperatures were not evident, because (1) although incubation temperature influenced offspring phenotypes and growth, it did so in similar ways in sons versus daughters, and (2) the relationship between phenotypic traits and fitness was similar in the two sexes, at least during preadult life. We were unable to reject a fourth model, in which TSD enhances offspring fitness by generating seasonal shifts in offspring sex ratio: that is, TSD allows

  1. Using daily satellite observations to estimate emissions of short-lived air pollutants on a mesoscopic scale

    NASA Astrophysics Data System (ADS)

    Mijling, B.; van der A, R. J.

    2012-09-01

    Emission inventories of air pollutants are crucial information for policy makers and form important input data for air quality models. Using satellite observations for emission estimates has important advantages over bottom-up emission inventories: they are spatially consistent, have high temporal resolution, and enable updates shortly after the satellite data become available. We present a new algorithm specifically designed to use daily satellite observations of column concentrations for fast updates of emission estimates of short-lived atmospheric constituents on a mesoscopic scale (˜25 × 25 km2). The algorithm needs only one forward model run from a chemical transport model to calculate the sensitivity of concentration to emission, using trajectory analysis to account for transport away from the source. By using a Kalman filter in the inverse step, optimal use of the a priori knowledge and the newly observed data is made. We apply the algorithm for NOx emission estimates of East China, using the CHIMERE model on a 0.25 degree resolution together with tropospheric NO2column retrievals of the OMI and GOME-2 satellite instruments. Closed loop tests show that the algorithm is capable of reproducing new emission scenarios. Applied with real satellite data, the algorithm is able to detect emerging sources (e.g., new power plants), and improves emission information for areas where proxy data are not or badly known (e.g., shipping emissions). Chemical transport model runs with the daily updated emission estimates provide better spatial and temporal agreement between observed and simulated concentrations, facilitating improved air quality forecasts.

  2. Nutrient Intake From Habitual Oral Diet in Patients With Severe Short Bowel Syndrome Living in the Southeastern United States

    PubMed Central

    Fernández-Estívariz, Concepción; Luo, Menghua; Umeakunne, Kay; Bazargan, Niloofar; Galloway, John R.; Leader, Lorraine M.; Ziegler, Thomas R.

    2008-01-01

    Background and Aims Little data are published on habitual home oral diet of short bowel syndrome (SBS) patients living in the United States. Methods We assessed habitual macro-and micronutrient intake from oral food and beverages in 19 stable patients with severe SBS who live in the Southeastern United States. Intestinal absorption of energy, fat, nitrogen (N) and carbohydrate (CHO) was determined in a metabolic ward setting. Results We studied 12 women and 7 men, age 48±3 years (mean±SE) receiving chronic PN for 31±8 months following massive small bowel resection (118±25 cm residual small bowel). Patients had intact (N=5), partial (N=9), or no residual colon (N=5). The subjects demonstrated severe malabsorption of energy (59±3% of oral intake), fat (41±5%), N (42±5%) and CHO (76±3%). Average oral energy intake was 2656±242 kcal/day (39±3 kcal/kg/day) and oral protein intake was 1.4 ±0.1 g/kg/d. Oral food/beverage intake constituted 49±4% of total (enteral + parenteral) daily fluid intake, 66±4% of total daily kcal and 58±5% of total daily N intake. Oral fat intake averaged 92±11g/day (≈ 35% of total oral energy). Oral fluid intake averaged 2712±240 ml/d, primarily from water, soft drinks, sweet tea and coffee. Simple sugars comprised 42±3% of oral CHO intake. Usual dietary intake of multiple micronutrients were below the Recommended Dietary Allowances (RDA) in a large percentage of patients: vitamin A (47%), vitamin D (79%), vitamin E (79%), vitamin K (63%), thiamine (42%), vitamin B6 (68%), vitamin B12 (11%), vitamin C (58%), folate (37%), iron (37%), calcium (63%), magnesium (79%) and zinc (68%). Only 7 patients (37%) were taking oral multivitamin-mineral supplements and only 6 subjects (37%) were taking oral iron and calcium supplements, respectively. Conclusions In these SBS patients living in the Southeastern United States, oral diet provides a significant proportion of daily nutrient intake. However, the types of foods and fluids consumed

  3. The effects of α-cellulose extraction and blue-stain fungus on retrospective studies of carbon and oxygen isotope variation in live and dead trees†

    USGS Publications Warehouse

    English, N.B.; McDowell, N.G.; Allen, C.D.; Mora, C.

    2011-01-01

    Tree-ring carbon and oxygen isotope ratios from live and recently dead trees may reveal important mechanisms of tree mortality. However, wood decay in dead trees may alter the δ13C and δ18O values of whole wood obscuring the isotopic signal associated with factors leading up to and including physiological death. We examined whole sapwood and α-cellulose from live and dead specimens of ponderosa pine (Pinus ponderosa), one-seed juniper (Juniperous monosperma), piñon pine (Pinus edulis) and white fir (Abies concolor), including those with fungal growth and beetle frass in the wood, to determine if α-cellulose extraction is necessary for the accurate interpretation of isotopic compositions in the dead trees. We found that the offset between the δ13C or δ18O values of α-cellulose and whole wood was the same for both live and dead trees across a large range of inter-annual and regional climate differences. The method of α-cellulose extraction, whether Leavitt-Danzer or Standard Brendel modified for small samples, imparts significant differences in the δ13C (up to 0.4‰) and δ18O (up to 1.2‰) of α-cellulose, as reported by other studies. There was no effect of beetle frass or blue-stain fungus (Ophiostoma) on the δ13C and δ18O of whole wood or α-cellulose. The relationships between whole wood and α-cellulose δ13C for ponderosa, piñon and juniper yielded slopes of ~1, while the relationship between δ18O of whole wood and α-cellulose was less clear. We conclude that there are few analytical or sampling obstacles to retrospective studies of isotopic patterns of tree mortality in forests of the western United States.

  4. Public health benefits of strategies to reduce greenhouse-gas emissions: health implications of short-lived greenhouse pollutants

    PubMed Central

    Smith, Kirk R.; Jerrett, Michael; Anderson, H Ross; Burnett, Richard T.; Stone, Vicki; Derwent, Richard; Atkinson, Richard W.; Cohen, Aaron; Shonkoff, Seth B.; Krewski, Daniel; Pope, C. Arden; Thun, Michael J.; Thurston, George

    2014-01-01

    In this report we review the health effects of three short-lived greenhouse pollutants—black carbon, ozone, and sulphates. We undertook new meta-analyses of existing time-series studies and an analysis of a cohort of 352 000 people in 66 US cities during 18 years of follow-up. This cohort study provides estimates of mortality effects from long-term exposure to elemental carbon, an indicator of black carbon mass, and evidence that ozone exerts an independent risk of mortality. Associations among these pollutants make drawing conclusions about their individual health effects difficult at present, but sulphate seems to have the most robust effects in multiple-pollutant models. Generally, the toxicology of the pure compounds and their epidemiology diverge because atmospheric black carbon, ozone, and sulphate are associated and could interact with related toxic species. Although sulphate is a cooling agent, black carbon and ozone could together exert nearly half as much global warming as carbon dioxide. The complexity of these health and climate effects needs to be recognised in mitigation policies. PMID:19942276

  5. Public health benefits of strategies to reduce greenhouse-gas emissions: health implications of short-lived greenhouse pollutants.

    PubMed

    Smith, Kirk R; Jerrett, Michael; Anderson, H Ross; Burnett, Richard T; Stone, Vicki; Derwent, Richard; Atkinson, Richard W; Cohen, Aaron; Shonkoff, Seth B; Krewski, Daniel; Pope, C Arden; Thun, Michael J; Thurston, George

    2009-12-19

    In this report we review the health effects of three short-lived greenhouse pollutants-black carbon, ozone, and sulphates. We undertook new meta-analyses of existing time-series studies and an analysis of a cohort of 352,000 people in 66 US cities during 18 years of follow-up. This cohort study provides estimates of mortality effects from long-term exposure to elemental carbon, an indicator of black carbon mass, and evidence that ozone exerts an independent risk of mortality. Associations among these pollutants make drawing conclusions about their individual health effects difficult at present, but sulphate seems to have the most robust effects in multiple-pollutant models. Generally, the toxicology of the pure compounds and their epidemiology diverge because atmospheric black carbon, ozone, and sulphate are associated and could interact with related toxic species. Although sulphate is a cooling agent, black carbon and ozone could together exert nearly half as much global warming as carbon dioxide. The complexity of these health and climate effects needs to be recognised in mitigation policies.

  6. Ozone Destruction in the Upper Troposphere/Lower Stratosphere from Short-Lived Halogens and Climate Impacts

    NASA Astrophysics Data System (ADS)

    Hossaini, Ryan; Chipperfield, Martyn; Montzka, Stephen; Rap, Alex; Dhomse, Sandip; Feng, Wuhu

    2014-05-01

    Halogens released from very short-lived substances (VSLS) can deplete ozone in the upper-troposphere and lower stratosphere where the perturbation can exert a large climate impact. In addition to the known ozone loss from natural biogenic bromine VSLS, such as bromoform (CHBr3), using a global atmospheric model we show that anthropogenic chlorine VSLS such as dichloromethane (CH2Cl2) - not regulated by the Montreal Protocol - also contribute. Although this impact is small compared to bromine VSLS at present, CH2Cl2 has industrial sources and observations show its atmospheric loading is increasing rapidly. We estimate a significant radiative effect of the bromine and chlorine VSLS-driven lower stratospheric ozone destruction of -0.11 Wm-2. The largest impact comes from ozone loss at high latitudes, where column ozone decreases due to VSLS are up to 6%. The trend in anthropogenic chlorine VSLS could cause a significant radiative forcing, especially if augmented by any trend in natural bromine VSLS. We also used the model to study the impact of iodine-containing VSLS such as methyl iodide (CH3I). Of the three halogens iodine has the largest leverage to destroy lower stratospheric ozone, but current limits based on IO observations indicate only a minor impact at present.

  7. SOLAR COSMIC-RAY INTERACTION WITH PROTOPLANETARY DISKS: PRODUCTION OF SHORT-LIVED RADIONUCLIDES AND AMORPHIZATION OF CRYSTALLINE MATERIAL

    SciTech Connect

    Trappitsch, R.; Ciesla, F. J.

    2015-05-20

    Solar cosmic-ray (SCR) interactions with a protoplanetary disk have been invoked to explain several observations of primitive planetary materials. In our own Solar System, the presence of short-lived radionuclides (SLRs) in the oldest materials has been attributed to spallation reactions induced in phases that were irradiated by energetic particles in the solar nebula. Furthermore, observations of other protoplanetary disks show a mixture of crystalline and amorphous grains, though no correlation between grain crystallinity and disk or stellar properties have been identified. As most models for the origin of crystalline grains would predict such correlations, it was suggested that amorphization by stellar cosmic-rays may be masking or erasing such correlations. Here we quantitatively investigate these possibilities by modeling the interaction of energetic particles emitted by a young star with the surrounding protoplanetary disk. We do this by tracing the energy evolution of SCRs emitted from the young star through the disk and model the amount of time that dust grains would spend in regions where they would be exposed to these particles. We find that this irradiation scenario cannot explain the total SLR content of the solar nebula; however, this scenario could play a role in the amorphization of crystalline material at different locations or epochs of the disk over the course of its evolution.

  8. Plasmacytoid dendritic cells are short-lived: reappraising the influence of migration, genetic factors and activation on estimation of lifespan

    PubMed Central

    Zhan, Yifan; Chow, Kevin V.; Soo, Priscilla; Xu, Zhen; Brady, Jamie L.; Lawlor, Kate E.; Masters, Seth L.; O’keeffe, Meredith; Shortman, Ken; Zhang, Jian-Guo; Lew, Andrew M.

    2016-01-01

    Plasmacytoid dendritic cells (pDCs) play an important role in immunity to certain pathogens and immunopathology in some autoimmune diseases. They are thought to have a longer lifespan than conventional DCs (cDCs), largely based on a slower rate of BrdU labeling by splenic pDCs. Here we demonstrated that pDC expansion and therefore BrdU labeling by pDCs occurs in bone marrow (BM). The rate of labeling was similar between BM pDCs and spleen cDCs. Therefore, slower BrdU labeling of spleen pDCs likely reflects the “migration time” (∼2 days) for BrdU labeled pDCs to traffic to the spleen, not necessarily reflecting longer life span. Tracking the decay of differentiated DCs showed that splenic pDCs and cDCs decayed at a similar rate. We suggest that spleen pDCs have a shorter in vivo lifespan than estimated utilizing some of the previous approaches. Nevertheless, pDC lifespan varies between mouse strains. pDCs from lupus-prone NZB mice survived longer than C57BL/6 pDCs. We also demonstrated that activation either positively or negatively impacted on the survival of pDCs via different cell-death mechanisms. Thus, pDCs are also short-lived. However, the pDC lifespan is regulated by genetic and environmental factors that may have pathological consequence. PMID:27112985

  9. Estimating surface fluxes of very short-lived halogens from aircraft measurements over the tropical Western Pacific

    NASA Astrophysics Data System (ADS)

    Feng, Liang; Palmer, Paul I.; Butler, Robyn; Harris, Neil; Carpenter, Lucy; Andrews, Steve; Atlas, Elliot; Pan, Laura; Salawitch, Ross; Donets, Valeria; Schauffler, Sue

    2016-04-01

    We use an inverse model approach to quantitatively understand the ocean flux and atmospheric transport of very short-lived halogenated species (VSLS) measured during the coordinated NERC CAST and NCAR CONTRAST aircraft campaigns over the Western Pacific during January/February 2014. To achieve this we have developed a nested GEOS-Chem chemistry transport model simulation of bromoform (CHBr3) and dibromomethane (CH2Br2), which has a spatial resolution of 0.25° (latitude) × 0.3125° (longitude) over the tropical Western Pacific region, and fed by boundary conditions from a coarser version of the model. We use archived 3-hourly 3-D fields of OH and j-values for CHBr3 photolysis, allowing us to linearly decompose these gases into tagged contributions from different geographical regions. Using these tagged tracers, we are able to use the maximum a posteriori probability (MAP) approach to estimate the VSLS sources by fitting the model to observations. We find that the resulting VSLS fluxes are significantly different from some previous studies. To interpret the results, we describe several observation system simulation experiments to understand the sensitivity of these flux estimates to observation errors as well as to the uncertainty in the boundary condition imposed around the nested grid.

  10. Fifteen non-CODIS autosomal short tandem repeat loci multiplex data from nine population groups living in Taiwan.

    PubMed

    Hwa, Hsiao-Lin; Chang, Yih-Yuan; Lee, James Chun-I; Lin, Chun-Yen; Yin, Hsiang-Yi; Tseng, Li-Hui; Su, Yi-Ning; Ko, Tsang-Ming

    2012-07-01

    The analysis of autosomal short tandem repeat (STR) loci is a powerful tool in forensic genetics. We developed a multiplex system in which 15 non-Combined DNA Index System autosomal STRs (D3S1744, D4S2366, D8S1110, D10S2325, D12S1090, D13S765, D14S608, Penta E, D17S1294, D18S536, D18S1270, D20S470, D21S1437, Penta D, and D22S683) could be amplified in one single polymerase chain reaction. DNA samples from 1,098 unrelated subjects of nine population groups living in Taiwan, including Taiwanese Han, indigenous Taiwanese of Taiwan Island, Tao, mainland Chinese, Filipinos, Thais, Vietnamese, Indonesians, and Caucasians, were collected and analyzed using this system. The distributions of the allelic frequencies and the forensic parameters of each population group were presented. The combined discrimination power and the combined power of exclusion were high in all population groups tested in this study. A multidimensional scaling plot of these nine population groups based on the Reynolds' genetic distances calculated from 15 autosomal STRs was constructed, and the genetic substructure in this area was presented. In conclusion, this 15 autosomal STR multiplex system provides highly informative STR data and appears useful in forensic casework and parentage testing in different populations.

  11. Attached and unattached fractions of short-lived radon decay products in outdoor environments: effect on the human respiratory system.

    PubMed

    Amrane, M; Oufni, L; Misdaq, M A

    2014-12-01

    The authors developed a model for determining the alpha- and beta-activities per unit volume of air due to radon ((222)Rn), thoron ((220)Rn) and their decay products attached and unattached to the aerosol in the outdoor air at the workplace in natural conditions at different locations in Morocco by using both CR-39 and LR-115 type II solid-state nuclear track detectors. In addition, the percentage of (218)Po, (214)Pb and (214)Po radionuclides attached to the aerosols and the unattached fraction f(j) for different values of the attachment rate were evaluated. Radon and thoron concentrations in outdoor air of the studied different locations were found to vary from 9.20±0.8 to 16.30±1.50 Bq m(-3) and 0.22±0.02 to 1.80±0.20 Bq m(-3), respectively. The committed equivalent doses due to the radon short-lived progeny (218)Po and (214)Po attached and unattached to the aerosol air were evaluated in different tissues of the respiratory tract of the members of the public from the inhalation of outdoor air.

  12. Time-resolved absorption and resonance Raman investigations of short-lived intermediates in solution or occluded in zeolites

    NASA Astrophysics Data System (ADS)

    Brémard, C.; Buntinx, G.; De Waele, V.; Didierjean, C.; Gener, I.; Poizat, O.

    1999-05-01

    Two examples of structural investigation of photogenerated short-lived transient species of aromatic compounds, by using time-resolved electronic absorption and resonance Raman spectroscopy are provided. The picosecond Raman spectra of the lowest excited singlet state (S 1) of 4,4'-bipyridine and 2,2'-bipyridine in solution are discussed first. The results provide strong evidence for a surprising asymmetric S 1 structure in which the electronic excitation and the consequent structural distortion are localized in one of the pyridyl rings, the other ring being almost unaffected. The laser photolysis of biphenyl occluded in the pores and cavities of ZSM-5 and faujasitic zeolites have been investigated in the nanosecond time-scale as functions of aluminium content, the extraframework cations, sample loading and intensity of photolysis. At low pump power and low aluminium content the triplet state of biphenyl is observed. At higher pump power and in aluminated zeolites, biphotonic ionization was observed to generate the cation radical. As the loading increased, the anion radical yield increased. This is characteristic of faujasitic zeolites in which scavenger molecules with restricted diffusional motions are confined in the vicinity of photoionized molecules. The lifetimes of cation radical were particularly long in aluminated ZSM-5 zeolites with efficient trapping sites of the photoejected electron.

  13. Short-lived charge-transfer excitons in organic photovoltaic cells studied by high-field magneto-photocurrent.

    PubMed

    Devir-Wolfman, Ayeleth H; Khachatryan, Bagrat; Gautam, Bhoj R; Tzabary, Lior; Keren, Amit; Tessler, Nir; Vardeny, Z Valy; Ehrenfreund, Eitan

    2014-07-29

    The main route of charge photogeneration in efficient organic photovoltaic cells based on bulk hetero-junction donor-acceptor blends involves short-lived charge-transfer excitons at the donor-acceptor interfaces. The cell efficiency is critically affected by the charge-transfer exciton recombination and dissociation processes. By measuring the magneto-photocurrent under ambient conditions at room temperature, we show here that magnetic field-induced spin-mixing among the charge-transfer exciton spin sublevels occurs in fields up to at least 8.5 Tesla. The resulting magneto-photocurrent increases at high fields showing non-saturating behaviour up to the highest applied field. We attribute the observed high-field spin-mixing mechanism to the difference in the donor-acceptor g-factors. The non-saturating magneto-photocurrent response at high field indicates that there exist charge-transfer excitons with lifetime in the sub-nanosecond time domain. The non-Lorentzian high-field magneto-photocurrent response indicates a dispersive decay mechanism that originates due to a broad distribution of charge-transfer exciton lifetimes.

  14. Solar Cosmic-ray Interaction with Protoplanetary Disks: Production of Short-lived Radionuclides and Amorphization of Crystalline Material

    NASA Astrophysics Data System (ADS)

    Trappitsch, R.; Ciesla, F. J.

    2015-05-01

    Solar cosmic-ray (SCR) interactions with a protoplanetary disk have been invoked to explain several observations of primitive planetary materials. In our own Solar System, the presence of short-lived radionuclides (SLRs) in the oldest materials has been attributed to spallation reactions induced in phases that were irradiated by energetic particles in the solar nebula. Furthermore, observations of other protoplanetary disks show a mixture of crystalline and amorphous grains, though no correlation between grain crystallinity and disk or stellar properties have been identified. As most models for the origin of crystalline grains would predict such correlations, it was suggested that amorphization by stellar cosmic-rays may be masking or erasing such correlations. Here we quantitatively investigate these possibilities by modeling the interaction of energetic particles emitted by a young star with the surrounding protoplanetary disk. We do this by tracing the energy evolution of SCRs emitted from the young star through the disk and model the amount of time that dust grains would spend in regions where they would be exposed to these particles. We find that this irradiation scenario cannot explain the total SLR content of the solar nebula; however, this scenario could play a role in the amorphization of crystalline material at different locations or epochs of the disk over the course of its evolution.

  15. Impact of short-lived non-CO2 mitigation on carbon budgets for stabilizing global warming

    NASA Astrophysics Data System (ADS)

    Rogelj, Joeri; Meinshausen, Malte; Schaeffer, Michiel; Knutti, Reto; Riahi, Keywan

    2015-07-01

    Limiting global warming to any level requires limiting the total amount of CO2 emissions, or staying within a CO2 budget. Here we assess how emissions from short-lived non-CO2 species like methane, hydrofluorocarbons (HFCs), black-carbon, and sulphates influence these CO2 budgets. Our default case, which assumes mitigation in all sectors and of all gases, results in a CO2 budget between 2011-2100 of 340 PgC for a >66% chance of staying below 2°C, consistent with the assessment of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Extreme variations of air-pollutant emissions from black-carbon and sulphates influence this budget by about ±5%. In the hypothetical case of no methane or HFCs mitigation—which is unlikely when CO2 is stringently reduced—the budgets would be much smaller (40% or up to 60%, respectively). However, assuming very stringent CH4 mitigation as a sensitivity case, CO2 budgets could be 25% higher. A limit on cumulative CO2 emissions remains critical for temperature targets. Even a 25% higher CO2 budget still means peaking global emissions in the next two decades, and achieving net zero CO2 emissions during the third quarter of the 21st century. The leverage we have to affect the CO2 budget by targeting non-CO2 diminishes strongly along with CO2 mitigation, because these are partly linked through economic and technological factors.

  16. {beta}-decay half-lives of new neutron-rich rare-earth isotopes {sup 159}Pm,{sup 162}Sm, and {sup 166}Gd

    SciTech Connect

    Ichikawa, S.; Asai, M.; Tsukada, K.; Nagame, Y.; Haba, H.; Shibata, M.; Sakama, M.; Kojima, Y.

    2005-06-01

    The new neutron-rich rare-earth isotopes {sup 159}Pm, {sup 162}Sm, and {sup 166}Gd produced in the proton-induced fission of {sup 238}U were identified using the JAERI on-line isotope separator (JAERI-ISOL) coupled to a gas-jet transport system. The half-lives of {sup 159}Pm, {sup 162}Sm, and {sup 166}Gd were determined to be 1.5 {+-} 0.2, 2.4 {+-} 0.5, and 4.8 {+-} 1.0 s respectively. The partial decay scheme of {sup 166}Gd was constructed from {gamma}{gamma}-coincidence data. A more accurate half-life value of 25.6 {+-} 2.2 s was obtained for the previously identified isotope {sup 166}Tb. The half-lives measured in the present study are in good agreement with the theoretical predictions calculated by the second generation of the gross theory with the atomic masses evaluated by Audi and Wapstra.

  17. Fowl play and the price of petrel: long-living Procellariiformes have peroxidation-resistant membrane composition compared with short-living Galliformes.

    PubMed

    Buttemer, William A; Battam, Harry; Hulbert, A J

    2008-08-23

    The membrane pacemaker hypothesis predicts that long-living species will have more peroxidation-resistant membrane lipids than shorter living species. We tested this hypothesis by comparing the fatty acid composition of heart phospholipids from long-living Procellariiformes (petrels and albatrosses) to those of shorter living Galliformes (fowl). The seabirds were obtained from by-catch of commercial fishing operations and the fowl values from published data. The 3.8-fold greater predicted longevity of the seabirds was associated with elevated content of peroxidation-resistant monounsaturates and reduced content of peroxidation-prone polyunsaturates and, consequently, a significantly reduced peroxidation index in heart membrane lipids, compared with fowl. Peroxidation-resistant membrane composition may be an important physiological trait for longevous species. PMID:18492647

  18. Improving Precision and Accuracy of Isotope Ratios from Short Transient Laser Ablation-Multicollector-Inductively Coupled Plasma Mass Spectrometry Signals: Application to Micrometer-Size Uranium Particles.

    PubMed

    Claverie, Fanny; Hubert, Amélie; Berail, Sylvain; Donard, Ariane; Pointurier, Fabien; Pécheyran, Christophe

    2016-04-19

    The isotope drift encountered on short transient signals measured by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) is related to differences in detector time responses. Faraday to Faraday and Faraday to ion counter time lags were determined and corrected using VBA data processing based on the synchronization of the isotope signals. The coefficient of determination of the linear fit between the two isotopes was selected as the best criterion to obtain accurate detector time lag. The procedure was applied to the analysis by laser ablation-MC-ICPMS of micrometer sized uranium particles (1-3.5 μm). Linear regression slope (LRS) (one isotope plotted over the other), point-by-point, and integration methods were tested to calculate the (235)U/(238)U and (234)U/(238)U ratios. Relative internal precisions of 0.86 to 1.7% and 1.2 to 2.4% were obtained for (235)U/(238)U and (234)U/(238)U, respectively, using LRS calculation, time lag, and mass bias corrections. A relative external precision of 2.1% was obtained for (235)U/(238)U ratios with good accuracy (relative difference with respect to the reference value below 1%). PMID:27031645

  19. [Nuclear spin catalysis in nanoreactors of living cells].

    PubMed

    Kol'tover, V K

    2013-01-01

    There is a great variety of chemical elements with magnetic and nonmagnetic isotopes in living cells. The question arises as to whether living cells can perceive the difference between magnetic and non-magnetic isotopes of chemical elements. It has been shown that bacteria Escherichia coli, which were previously enriched with the magnetic isotope of magnesium, 25Mg, essentially faster adapt to the new growth media in comparison with the cells, which were enriched with the nonmagnetic isotopes, 24Mg or 26Mg. In the experiments with another commonly accepted cell model, yeast Saccharomyces cerevisiae, it has been shown that the magnetic 25Mg, in comparison with the nonmagnetic 24Mg, essentially better stimulates recovery of the cells after short wave UV irradiation. Thus, for the first time, the magnetic isotope effects in vivo have been discovered. These findings reveal the novel, based on the stable magnetic isotopes, ways of control over efficiency and reliability of biological systems.

  20. Evaluation of on-line pyrolysis coupled to isotope ratio mass spectrometry for the determination of position-specific (13)C isotope composition of short chain n-alkanes (C6-C12).

    PubMed

    Gilbert, Alexis; Yamada, Keita; Yoshida, Naohiro

    2016-06-01

    We measured (13)C intramolecular isotopic composition of commercially available short-chain hydrocarbons (n-C6-n-C12) using (13)C-NMR. Results show that the main variation is between the terminal and the sub-terminal C-atom positions. Site-preference (difference in δ(13)C values between terminal and sub-terminal C-atom positions) among all the samples varies between -12.2‰ and +8.4‰. Comparison of these results with those obtained using on-line pyrolysis coupled with GC-C-IRMS show that the thermal cracking of hydrocarbons occurs with a good isotopic fidelity between terminal and sub-terminal C-atom positions of the starting material and the related pyrolysis products (methane and ethylene). On-line pyrolysis coupled with GC-C-IRMS can thus be used for tracing hydrocarbons biogeochemical processes.

  1. The short-lived (<2 minutes) acceleration of protons to >13 GeV in association with solar flares.

    NASA Astrophysics Data System (ADS)

    McCracken, Ken; Shea, Margaret Ann; Smart, Don

    2016-04-01

    release) mechanism must then decrease greatly in efficiency abruptly ~3 minutes after it started. We note that this is not a unique example; the >10GeV particle pulse in the GLE of 20 January 2005 persisted for only 3 minutes; and a >4.5 GeV pulse at the commencement of the GLE of 7 December, 1982, only lasted one minute. We conclude with a comparison between these observations and the predictions of several proposed acceleration models. We conclude that these short-lived bursts of highly relativistic cosmic rays have been accelerated in the reconnection regions associated with large solar flares. In the greater majority of cases, the short-lived, high energy cosmic ray pulse at the commencement of a GLE is followed by a slowly rising component accelerated in the CME generated shock.

  2. Current and future contributions of local emissions from shipping and hydrocarbon extraction flaring to short lived pollutants in the Arctic

    NASA Astrophysics Data System (ADS)

    Marelle, L.; Raut, J. C.; Law, K.; Thomas, J. L.; Fast, J. D.; Berg, L. K.; Shrivastava, M. B.; Easter, R. C.; Herber, A. B.

    2015-12-01

    The Arctic is increasingly open to human activity due to rapid Arctic warming, associated with decreased sea ice extent and snow cover. While pollution from in-Arctic sources is currently low, oil and gas extraction and marine traffic could become a significant future source of short-lived pollutants (aerosols, ozone) in the Arctic. It is currently unclear if these local sources might become significant compared to the long-range transport of anthropogenic pollution from the midlatitudes, which is currently the main source of Arctic pollution. Here, we investigate the current (2012) and future (2050) impact of emissions from shipping and oil and gas extraction on Arctic aerosols and ozone, in relation to emissions from long-range transport. These impacts are determined by performing 6-month long, quasi-hemispheric simulations over the Arctic region with the WRF-Chem model. Our regional simulations include up-to-date representations of cloud/aerosol interactions and secondary organic aerosol formation developed recently for WRF-Chem. In order to determine the impact of Arctic shipping and oil and gas extraction, we use recent emission inventories by Winther et al., 2014 for local shipping and ECLIPSEv5 for oil and gas flaring. Both inventories suggest that current and future emissions from these sources are higher than previous estimates. Simulations are evaluated using measurements at Arctic surface sites and aircraft campaigns (ACCESS, YAK) in 2012. Model results are then used to assess the impact of Arctic shipping and oil and gas flaring on modeled surface aerosol and ozone concentrations, direct aerosol and ozone radiative effects, indirect aerosol radiative effects, and aerosol deposition. Results are used to determine if these local emissions are expected to have a significant influence on these quantities at the local or the regional scale, compared to emissions transported from the midlatitudes and to other emission sources, including boreal fires.

  3. Sediment fingerprinting with long- and short-lived radionuclide tracers in the Root River watershed, southeastern Minnesota

    NASA Astrophysics Data System (ADS)

    Belmont, P.; Stout, J. C.

    2015-12-01

    The field of sediment fingerprinting has evolved rapidly over the past decade and is poised to improve our understanding not only of sediment sources, but also the routing of sediment through watersheds. Such information is essential for understanding and modeling human impacts on erosion and sediment routing at the watershed scale. In this study we use long- (Beryllium-10, 10Be) and short-lived (Lead-210 and Cesium-137, 210Pb and 137Cs, respectively) radionuclide tracers associated with suspended sediment to quantify sediment sources and channel-floodplain exchange across a range of watershed scales from 10 km2 to 4500 km2 in in the Root River, southeastern Minnesota, USA. The uppermost quarter of the Root River watershed was glaciated repeatedly during the late Pleistocene and is characterized by low relief agricultural fields and fine textured soils. The remainder of the watershed lies within the driftless area of the upper Midwestern US, which has not been glaciated in at least the past 500,000 years, and is characterized by karst topography, relatively steep hillslopes and bedrock channels that debouch into a wide, aggrading alluvial valley. The structure of the landscape exerts strong control on sediment generation and transport. Geochemical results indicate a highly variable erosion history, with significant variability of 10Be concentrations in source areas (agricultural fields, forested hillslopes, and alluvial floodplains and terraces) and inverted 10Be depth profiles (higher concentrations at depth) in floodplains, suggesting unsteady erosion and significant storage of legacy sediment. Concentrations of 10Be and 210Pb associated with suspended sediment show a systematic disparity in normalized concentrations, indicating that significant storage and re-suspension occurs in both systems as the sediment is routed through the channel-floodplain complex.

  4. How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short lived bromocarbons?

    NASA Astrophysics Data System (ADS)

    Yang, X.; Abraham, N. L.; Archibald, A. T.; Braesicke, P.; Keeble, J.; Telford, P.; Warwick, N. J.; Pyle, J. A.

    2014-04-01

    Naturally produced very short-lived substances (VSLS), like bromocarbons, account for almost a quarter of the current stratospheric inorganic bromine, Bry. Following VSLS oxidation, bromine radicals (Br and BrO) can catalytically destroy ozone. The extent to which possible increases in surface emissions or transport of these VSLS bromocarbons to the stratosphere could counteract the effect of halogen reductions under the Montreal Protocol is an important policy question. Here by using a chemistry-climate model, UM-UKCA, we investigate the impact of a hypothetical increase in VSLS on ozone and how that impact depends on the background concentrations of chlorine and bromine. Our model experiments indicate that for a ~5 ppt increase in Bry from VSLS, the local ozone loss in the lowermost stratosphere of the Southern Hemisphere (SH) may reach up to 10% in the annual mean; the ozone loss in the Northern Hemisphere (NH) is smaller (4-6%). There is more ozone loss following an increase in VSLS burden under a high stratospheric chlorine background than under a low chlorine background indicating the importance of the inter-halogen reactions. For example, the rate of decline of the stratospheric ozone concentration as a function of Bry is higher by about 30-40% when stratospheric Cly is ~3 ppb (present day) compared with Cly of ~0.8 ppb (apre-industrial or projected future situation). Although bromine plays an important role in destroying ozone, inorganic chlorine is the dominant halogen compound. Even if bromine levels from natural VSLS were to increase significantly later this century, changes in the concentration of ozone will be dominated by the recovery of anthropogenic chlorine. Our calculation suggests that for a 5 ppt increase in Bry from VSLS, the Antarctic ozone hole recover date could be delayed by approximately 7 years.

  5. How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short-lived bromocarbons?

    NASA Astrophysics Data System (ADS)

    Yang, X.; Abraham, N. L.; Archibald, A. T.; Braesicke, P.; Keeble, J.; Telford, P. J.; Warwick, N. J.; Pyle, J. A.

    2014-10-01

    Naturally produced very short-lived substances (VSLS) account for almost a quarter of the current stratospheric inorganic bromine, Bry. Following VSLS oxidation, bromine radicals (Br and BrO) can catalytically destroy ozone. The extent to which possible increases in surface emissions or transport of these VSLS bromocarbons to the stratosphere could counteract the effect of halogen reductions under the Montreal Protocol is an important policy question. Here, by using a chemistry-climate model, UM-UKCA, we investigate the impact of a hypothetical doubling (an increase of 5 ppt Bry) of VSLS bromocarbons on ozone and how the resulting ozone changes depend on the background concentrations of chlorine and bromine. Our model experiments indicate that for the 5 ppt increase in Bry from VSLS, the ozone decrease in the lowermost stratosphere of the Southern Hemisphere (SH) may reach up to 10% in the annual mean; the ozone decrease in the Northern Hemisphere (NH) is smaller (4-6%). The largest impact on the ozone column is found in the Antarctic spring. There is a significantly larger ozone decrease following the doubling of the VSLS burden under a high stratospheric chlorine background than under a low chlorine background, indicating the importance of the inter-halogen reactions. For example, the decline in the high-latitude, lower-stratospheric ozone concentration as a function of Bry is higher by about 30-40% when stratospheric Cly is ~ 3 ppb (present day), compared with Cly of ~ 0.8 ppb (a pre-industrial or projected future situation). Bromine will play an important role in the future ozone layer. However, even if bromine levels from natural VSLS were to increase significantly later this century, changes in the concentration of ozone will likely be dominated by the decrease in anthropogenic chlorine. Our calculation suggests that for a 5 ppt increase in Bry from VSLS, the Antarctic ozone hole recovery date could be delayed by approximately 6-8 years, depending on Cly

  6. The effects of short-lived radionuclides and porosity on the early thermo-mechanical evolution of planetesimals

    NASA Astrophysics Data System (ADS)

    Lichtenberg, Tim; Golabek, Gregor J.; Gerya, Taras V.; Meyer, Michael R.

    2016-08-01

    The thermal history and internal structure of chondritic planetesimals, assembled before the giant impact phase of chaotic growth, potentially yield important implications for the final composition and evolution of terrestrial planets. These parameters critically depend on the internal balance of heating versus cooling, which is mostly determined by the presence of short-lived radionuclides (SLRs), such as 26Al and 60Fe, as well as the heat conductivity of the material. The heating by SLRs depends on their initial abundances, the formation time of the planetesimal and its size. It has been argued that the cooling history is determined by the porosity of the granular material, which undergoes dramatic changes via compaction processes and tends to decrease with time. In this study we assess the influence of these parameters on the thermo-mechanical evolution of young planetesimals with both 2D and 3D simulations. Using the code family I2ELVIS/I3ELVIS we have run numerous 2D and 3D numerical finite-difference fluid dynamic models with varying planetesimal radius, formation time and initial porosity. Our results indicate that powdery materials lowered the threshold for melting and convection in planetesimals, depending on the amount of SLRs present. A subset of planetesimals retained a powdery surface layer which lowered the thermal conductivity and hindered cooling. The effect of initial porosity was small, however, compared to those of planetesimal size and formation time, which dominated the thermo-mechanical evolution and were the primary factors for the onset of melting and differentiation. We comment on the implications of this work concerning the structure and evolution of these planetesimals, as well as their behavior as possible building blocks of terrestrial planets.

  7. Integrated Assessment on Effects of Short-Lived Climate Pollutants (SLCPs) in Asia based on Numerical Models

    NASA Astrophysics Data System (ADS)

    Takemura, T.; Sudo, K.; Ueda, K.; Masutomi, Y.; Watanabe, S.; Nakata, M.; Takahashi, H. G.; Goto, D.

    2015-12-01

    Air pollution over the Asian region is a serious social problem. For example, activities of the Climate and Clean Air Coalition (CCAC) under the UNFCCC focus on raising awareness and improving scientific understanding of short-lived climate pollutant (SLCP) impacts and mitigation strategies. Our Japanese research project is searching an optimum reduction path of SLCPs considering climate change, health impacts, and agricultural damages. For this purpose, we use aerosol and chemistry models, SPRINTARS and CHASER, respectively, which have been developed by our group, coupled with a general circulation model, MIROC. In the phase 1 of this project, changes in concentrations and radiative forcing of each major SLCPs originating from China, east Asia, southeast Asia, and south Asia in the last 30 years are estimated with the models. Transient simulations along the new emission scenario, SSPs (Shared Socio-economic Pathways) are executed using the MIROC-SPRINTARS/CHASER with ocean circulation in the phase 2 to analyze full feedbacks including hydrological cycle affected by SLCPs. These simulated results will be utilized to estimate health and agricultural impacts of SLCPs. In this presentation, we discuss the optimum reduction path of SLCPs taking both mitigation of global warming and air pollution into consideration. Acknowledgements: Simulations in this study were executed with the supercomputer system of the National Institute for Environmental Studies, Japan. This study is partly supported by the Environment Research and Technology Development Fund (S-12-3) of the Ministry of the Environment, Japan and JSPS KAKENHI Grant Number 15H01728 and 15K12190.

  8. Transport of very short-lived halocarbons from the Indian Ocean to the stratosphere through the Asian monsoon circulation

    NASA Astrophysics Data System (ADS)

    Fiehn, Alina; Hepach, Helmke; Atlas, Elliot; Quack, Birgit; Tegtmeier, Susann; Krüger, Kirstin

    2016-04-01

    Halogenated organic compounds are naturally produced in the ocean and emitted to the atmosphere. The halogenated very short-lived substances (VSLS), such as bromoform, have atmospheric lifetimes of less than half a year. When VSLS reach the stratosphere, they enhance ozone depletion and thus impact the climate. During boreal summer, the Asian monsoon circulation transfers air masses from the Asian troposphere to the global stratosphere. Still, the extent to which VSLS from the Indian Ocean contribute to the stratospheric halogen burden and their exact origin is unclear. Here we show that the monsoon circulation transports VSLS from the Indian Ocean to the stratosphere. During the research cruises SO234-2 and SO235 in July-August 2014 onboard RV SONNE, we measured oceanic and atmospheric concentrations of bromoform (tropical lifetime at 10 km = 17 days), dibromomethane (150 days) and methyl iodide (3.5 days) in the subtropical and tropical West Indian Ocean and calculated their emission strengths. We use the Langrangian transport model FLEXPART driven by ERA-Interim meteorological fields to investigate the transport of oceanic emissions in the atmosphere. We analyze the direct contribution of observed bromoform emissions to the stratospheric halogen budget with forward trajectories. Furthermore, we investigate the connection between the Asian monsoon anticyclone and the oceanic source regions using backward trajectories. The West Indian Ocean is a strong source region of VSLS to the atmosphere and the monsoon transport is fast enough for bromoform to reach the stratosphere. However, the main source regions for the entrainment of oceanic air masses through the Asian monsoon anticyclone are the West Pacific and Bay of Bengal as well as the Arabian Sea. Our findings indicate that changes in emission or circulation in this area due to climate change can directly affect the stratospheric halogen burden and thus the ozone layer.

  9. SMA observations towards the compact, short-lived bipolar water maser outflow in the LkHα234 region

    NASA Astrophysics Data System (ADS)

    Girart, J. M.; Torrelles, J. M.; Estalella, R.; Curiel, S.; Anglada, G.; Gómez, J. F.; Carrasco-González, C.; Cantó, J.; Rodríguez, L. F.; Patel, N. A.; Trinidad, M. A.

    2016-10-01

    We present Submillimeter Array (SMA) 1.35 mm subarcsecond angular resolution observations towards the LkHα234 intermediate-mass star-forming region. The dust emission arises from a filamentary structure of ˜5 arcsec (˜4500 au) enclosing VLA 1-3 and MM 1, perpendicular to the different outflows detected in the region. The most evolved objects are located at the southeastern edge of the dust filamentary structure and the youngest ones at the northeastern edge. The circumstellar structures around VLA 1, VLA 3, and MM 1 have radii between ˜200 and ˜375 au and masses in the ˜0.08-0.3 M⊙ range. The 1.35 mm emission of VLA 2 arises from an unresolved (r ≲ 135 au) circumstellar disc with a mass of ˜0.02 M⊙. This source is powering a compact (˜4000 au), low radial velocity (˜7 km s-1) SiO bipolar outflow, close to the plane of the sky. We conclude that this outflow is the `large-scale' counterpart of the short-lived, episodic, bipolar outflow observed through H2O masers at much smaller scales (˜180 au), and that has been created by the accumulation of the ejection of several episodic collimated events of material. The circumstellar gas around VLA 2 and VLA 3 is hot (˜130 K) and exhibits velocity gradients that could trace rotation. There is a bridge of warm and dense molecular gas connecting VLA 2 and VLA 3. We discuss the possibility that this bridge could trace a stream of gas between VLA 3 and VLA 2, increasing the accretion rate on to VLA 2 to explain why this source has an important outflow activity.

  10. Re-Os isotopic evidence for long-lived heterogeneity and equilibration processes in the Earth's upper mantle.

    PubMed

    Meibom, Anders; Sleep, Norman H; Chamberlain, C Page; Coleman, Robert G; Frei, Robert; Hren, Michael T; Wooden, Joseph L

    2002-10-17

    The geochemical composition of the Earth's upper mantle is thought to reflect 4.5 billion years of melt extraction, as well as the recycling of crustal materials. The fractionation of rhenium and osmium during partial melting in the upper mantle makes the Re-Os isotopic system well suited for tracing the extraction of melt and recycling of the resulting mid-ocean-ridge basalt. Here we report osmium isotope compositions of more than 700 osmium-rich platinum-group element alloys derived from the upper mantle. The osmium isotopic data form a wide, essentially gaussian distribution, demonstrating that, with respect to Re-Os isotope systematics, the upper mantle is extremely heterogeneous. As depleted and enriched domains can apparently remain unequilibrated on a timescale of billions of years, effective equilibration seems to require high degrees of partial melting, such as occur under mid-ocean ridges or in back-arc settings, where percolating melts enhance the mobility of both osmium and rhenium. We infer that the gaussian shape of the osmium isotope distribution is the signature of a random mixing process between depleted and enriched domains, resulting from a 'plum pudding' distribution in the upper mantle, rather than from individual melt depletion events.

  11. GC/MS method for determining carbon isotope enrichment and concentration of underivatized short-chain fatty acids by direct aqueous solution injection of biogas digester samples.

    PubMed

    Mulat, Daniel Girma; Feilberg, Anders

    2015-10-01

    In anaerobic digestion of organic matter, several metabolic pathways are involved during the simultaneous production and consumption of short-chain fatty acids (SCFA) in general and acetate in particular. Understanding the role of each pathway requires both the determination of the concentration and isotope enrichment of intermediates in conjunction with isotope labeled substrates. The objective of this study was to establish a rapid and simple GC/MS method for determining the isotope enrichment of acetate and concentration of underivatized short-chain fatty acids (SCFA) in biogas digester samples by direct liquid injection of acidified aqueous samples. Sample preparation involves only acidification, centrifugation and filtration of the aqueous solution followed by direct injection of the aqueous supernatant solution onto a polar column. With the sample preparation and GC/MS conditions employed, well-resolved and sharp peaks of underivatized SCFA were obtained in a reasonably short time. Good recovery (96.6-102.3%) as well as low detection (4-7 µmol/L) and quantification limits (14-22 µmol/L) were obtained for all the 6 SCFA studied. Good linearity was achieved for both concentration and isotope enrichment measurement with regression coefficients higher than 0.9978 and 0.9996, respectively. The method has a good intra- and inter-day precision with a relative standard deviation (RSD) below 6% for determining the tracer-to-tracee ratio (TTR) of both [2-(13)C]acetate and [U-(13)C]acetate. It has also a good intra- and inter-day precision with a RSD below 6% and 5% for determining the concentration of standard solution and biogas digester samples, respectively. Acidification of biogas digester samples with oxalic acid provided the low pH required for the protonation of SCFA and thus, allows the extraction of SCFA from the complex sample matrix. Moreover, oxalic acid was the source of formic acid which was produced in the injector set at high temperature. The produced

  12. Pd0-mediated rapid cross-coupling reactions, the rapid C-[11C]methylations, revolutionarily advancing the syntheses of short-lived PET molecular probes.

    PubMed

    Suzuki, Masaaki; Doi, Hisashi; Koyama, Hiroko; Zhang, Zhouen; Hosoya, Takamitsu; Onoe, Hirotaka; Watanabe, Yasuyoshi

    2014-06-01

    Positron emission tomography is a noninvasive method for monitoring drug (or diagnostic) behavior and its localization on the target molecules in the living systems, including the human body, using a short-lived positron-emitting radionuclide. New methodologies for introducing representative short-lived radionuclides, (11)C and (18)F, into the carbon frameworks of biologically active organic compounds have been established by developing rapid C-[(11)C]methylations and C-[(18)F]fluoromethylations using rapid Pd(0)-mediated cross-coupling reactions between [(11)C]methyl iodide (sp(3)-hybridized carbon) and an excess amount of organotributylstannane or organoboronic acid ester having sp(2) (phenyl, heteroaromatic, or alkenyl), sp(alkynyl), or sp(3) (benzyl and cinnamyl)-hybridized carbons; and [(18)F]fluoromethyl halide (iodide or bromide) and an organoboronic acid ester, respectively. These rapid reactions provide a firm foundation for an efficient and general synthesis of short-lived (11)C- or (18)F-labeled PET molecular probes to promote in vivo molecular imaging studies.

  13. Investigating land-atmosphere exchange using observations of the stable isotopes in water vapour during a short term field campaign

    NASA Astrophysics Data System (ADS)

    Parkes, S. D.; Griffiths, A.; Wang, L.; McCabe, M. F.; Chambers, S. D.; Williams, A. G.; Element, A.; Strauss, J.

    2014-12-01

    Evaporation sources and meteorological conditions at the source of evaporation are important variables affecting the stable isotopes in water vapour. Isotopes therefore provide complimentary information to more conventional techniques used in land-atmosphere exchange studies. Augmenting in-situ water vapour isotope measurements, soil and plant water isotopic analysis, and meteorological measurements collected during a 2 week field campaign to a semi-arid grassland site in NSW, Australia, the relationship between land-atmosphere exchange processes and the water vapour isotopic composition was investigated. Back-trajectory analysis was used to provide insight into the role of large scale hydrological processes on the water vapour isotopic composition. During the campaign clear dry conditions were observed leading to strong diurnal cycles for the evapotranspiration fluxes. For diurnal times, the d-excess of the water vapour showed a strong relationship with the evapotranspiration fluxes. During the morning transition period when the convective boundary layer was being established and evapotranspiration fluxes were increasing, the d-excess increased sharply. Plant and soil water samples indicated non-steady state transpiration fluxes led to these higher values. In the afternoon when the evapotranspiration fluxes decreased and the humidity approached saturation, the d-excess of water vapour declined approaching values approximately in equilibrium with the soil water. On the other hand, the diurnal cycle of the δ2H did not show a consistent trend with the local meteorology, but showed a stronger relationship with the sea surface temperature of the oceanic moisture source and dehydration pathways during transport of atmospheric moisture to the site. The interpretation from these results indicates that the d-excess variable may be a better variable for investigating local land-atmosphere exchange as the δ2H is strongly influenced by changes in the synoptic scale

  14. Russian policy on methane emissions in the oil and gas sector: A case study in opportunities and challenges in reducing short-lived forcers

    NASA Astrophysics Data System (ADS)

    Evans, Meredydd; Roshchanka, Volha

    2014-08-01

    Methane is a potent greenhouse gas, 21 times as powerful as carbon dioxide in contributing to climate change on a ton-for-ton basis. Methane, along with other short-lived forcers such as black carbon and tropospheric ozone, could play an important role in addressing global climate change. This stems both from their overall effect on climate systems, and from their concentrated impact in the short term. Because reducing emissions of such short-lived pollutants may have a large near-term impact in slowing climate change, the United States and other countries have come together to cooperate under the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants, and other partnerships such as the Global Methane Initiative. For global impact, the success of such partnerships depends on their ability to scale up project-specific emission reductions. This paper assesses options and challenges for scaling based on a case study of Russia's oil and gas sector. We examine the challenges to achieving far-reaching emission reductions, successes of companies to date, how Russia has sought to influence methane emissions through its environmental fine system, and options for helping companies achieve large-scale emission reductions in the future through simpler and clearer incentives.

  15. Application of mass spectrometric techniques for the trace analysis of short-lived iodine-containing volatiles emitted by seaweed.

    PubMed

    Kundel, Michael; Thorenz, Ute R; Petersen, Jan H; Huang, Ru-Jin; Bings, Nicolas H; Hoffmann, Thorsten

    2012-04-01

    Knowledge of the composition and emission rates of iodine-containing volatiles from major widespread seaweed species is important for modeling the impact of halogens on gas-phase atmospheric chemistry, new particle formation, and climate. In this work, we present the application of mass spectrometric techniques for the quantification of short-lived iodine-containing volatiles emitted by eight different seaweeds from the intertidal zone of Helgoland, Germany. A previously developed online time-of-flight aerosol mass spectrometric method was used to determine I(2) emission rates and investigate temporally resolved emission profiles. Simultaneously, iodocarbons were preconcentrated on solid adsorbent tubes and quantified offline using thermodesorption-gas chromatography-mass spectrometry. The total iodine content of the seaweeds was determined using microwave-assisted tetramethylammonium hydroxide extraction followed by inductively coupled-plasma mass spectrometry analysis. The highest total iodine content was found in the Laminariales, followed by the brown algae Ascophyllum nodosum, Fucus vesiculosus, Fucus serratus, and both red algae Chondrus crispus and Delesseria sanguinea. Laminariales were found to be the strongest I(2) emitters. Time series of the iodine release of Laminaria digitata and Laminaria hyperborea showed a strong initial I(2) emission when first exposed to air followed by an exponential decline of the release rate. For both species, I(2) emission bursts were observed. For Laminaria saccharina und F. serratus, a more continuous I(2) release profile was detected, however, F. serratus released much less I(2). A. nodosum and F. vesiculosus showed a completely different emission behavior. The I(2) emission rates of these species were slowly increasing with time during the first 1 to 2 h until a more or less stable I(2) emission rate was reached. The lowest I(2) emission rates were detected for the red algae C. crispus and D. sanguinea. Total iodocarbon

  16. On the Relation between Stratospheric Chlorine/Bromine Loading and Short-Lived Tropospheric Source Gases. Appendix D

    NASA Technical Reports Server (NTRS)

    Ko, Malcolm K. W.; Sze, Nien-Dak; Scott, Courtney J.; Weisenstein, Debra K.

    1997-01-01

    Current methods for estimating the concentrations of inorganic chlorine/bromine species Cl(y)/Br(y) in the stratosphere due to decomposition of tropospheric source gases assume that the Cl(y)/Br(y) concentration in the stratosphere is determined mainly by the balance between production from in situ oxidation of the source gases in the stratosphere and removal by transport of Cl(y)/Br(y) out of the stratosphere. The rationale being that for source gases whose lifetimes are of the order of several months or longer the concentration of Cl(y)/Br(y) in the troposphere is small because they are produced at a relatively slow rate and also removed efficiently by washout processes. As a result of the small concentration, the rate at which Cl(y)/Br(y) is transported to the stratosphere is expected to be small compared to the in situ stratospheric production. Thus the transport of Cl(y)/Br(y) from the troposphere contributes little to the stratospheric concentration. In contrast, the origin of stratospheric Cl(y)/Br(y) from reactive source gases with tropospheric lifetimes comparable to the washout lifetime of Cl(y)/Br(y) (of the order of 10-30 days) in the troposphere is distinctly different. The in situ source in the stratosphere is expected to be significantly smaller because only a small portion of the source gas is expected to survive the troposphere to be transported into this region. At the same time these short-lived source gases produce appreciable amounts of Cl(y)/Br(y) in the troposphere such that transport to the stratosphere offers a larger source for stratospheric Cl(y)/Br(y) than in situ production. Thus, for reactive source species, simple methods of estimating the concentration of stratospheric Cl(y)/Br(y) that ignore the tropospheric contribution will seriously underestimate the loading. Therefore estimation of the stratospheric Cl(y)/Br(y) loading requires not only measurements of tropospheric source gases but also measurements of Cl(y)/Br(y) at the

  17. Tree ring isotopes of beech and spruce in response to short-term climate variability across Central European sites: Common and contrasting physiological mechanisms

    NASA Astrophysics Data System (ADS)

    Weigt, Rosemarie; Klesse, Stefan; Treydte, Kerstin; Frank, David; Saurer, Matthias; Siegwolf, Rolf T. W.

    2016-04-01

    The combined study of tree-ring width and stable C and O isotopes provides insight in the coherences between carbon allocation during stem growth and the preceding conditions of gas exchange and formation of photosynthates as all influenced by environmental variation. In this large-scale study comprising 10 sites across a range of climate gradients (temperature, precipitation) throughout Central Europe, we investigated tree-rings in European beech (Fagus sylvatica) and Norway spruce (Picea abies) trees. The sampling design included larger and smaller trees. The short-term, i.e. year-to-year, variability in the isotope time series over 100 yrs was analyzed in relation to tree-ring growth and climate variation. The generally strong correlation between the year-to-year differences in δ13C (corrected for the atmospheric shift due to 13C-depleted CO2 from fossil combustion) and δ18O across most sites emphasized the role of stomatal conductance in controlling leaf gas exchange. However, the correlation between both isotopes decreased during some periods. At several sites this reduction in correlation was particularly pronounced during recent decades. This suggests a decoupling between stomatal and photosynthetic responses to environmental conditions on the one hand, and carbon allocation to stem tissue on the other hand. Variability in the isotopic ratio largely responded to summer climate, but was weakly correlated to annual stem growth. In contrast, climate sensitivity of radial growth in both species was rather site-dependent, and was strongest at the driest (in terms of soil water capacity) site. We will also present results of isotope responses with respect to extreme climate events. Understanding the underlying physiological mechanisms controlling the short-term variation in tree-ring signals will help to assess and more precisely constrain the possible range of growth performance of these ecologically and economically important tree species under future climate

  18. NEW ACTIVE MEDIA AND ELEMENTS OF LASER SYSTEMS: Influence of short-lived color centers on the lifetime of a metastable level of neodymium in silicate glasses

    NASA Astrophysics Data System (ADS)

    Dzhibladze, M. I.; Lazarev, L. E.

    1987-11-01

    It was found that the short-lived color centers formed in neodymium-activated silicate glasses under the action of the violet part of the pump spectrum increased the lifetime of a neodymium metastable level by more than an order of magnitude in needle-shaped waveguide lasers. The highly efficient suppression of superradiance and a strong increase in the gain of the active element were due to stimulated decay of the color centers accompanying absorption of photons emitted by the neodymium.

  19. Living on the edge: The oxygen isotope record of Eocene Basins at the margin of the Cenozoic North American plateau

    NASA Astrophysics Data System (ADS)

    Methner, Katharina; Mulch, Andreas; Chamberlain, Page

    2013-04-01

    Topography has a strong impact on atmospheric circulation and precipitation patterns and is a key element in reconstructing the dynamics of mountain building processes. The topographic evolution of the world's major orogens remains one of the most important questions when discussing the interactions among tectonics, climate, and Earth surface processes. Here, we focus on the spatial and temporal development of topography and relief in the western North American Cordillera and how changes in the topography may have affected precipitation patterns and vice versa. In this context, we sampled more than 20 sections in Eocene to Oligocene terrestrial (intermontane?) basins (Chumstick, Swauk, and Chuckanut) in western and central Washington (USA) to the W and E of the modern Cascades. Oxygen isotope analysis of pedogenic carbonate in these sections allows us to reconstruct the isotopic composition of ancient soilwater or groundwater, and ultimately precipitation. Oxygen isotope measurements of pedogenic concretions and calcic horizons interestingly yield uniformly low δ18O values of 10 to 13‰ SMOW despite the proximity of all sections to the Pacific moisture source. These extremely low oxygen isotope values can result from (1) highly 18O-depleted meteoric waters (soil- or groundwater), (2) burial diagenesis at moderate temperatures and interaction with 18O-depleted (ground)water, and (3) high burial temperatures and and exchange with basins brines. Vitrinite reflectance data and preservation of primary soil structures such as rootlets, root casts, burrows, or even preserved wood fragments clearly show that some of the low-d18O sections were not affected by high degrees of burial diagenesis. Thus, we believe that the primary isotopic signal of ancient soil- or groundwater is preserved at least in parts (if not in all) of these basins. Low δ18O values of pedogenic carbonate require highly 18O-depleted meteoric water, which in turn, would require high elevation either at

  20. Daily variation of radon gas and its short-lived progeny concentration near ground level and estimation of aerosol residence time

    NASA Astrophysics Data System (ADS)

    M, Mohery; A, M. Abdallah; A, Ali; S, S. Baz

    2016-05-01

    Atmospheric concentrations of radon (222Rn) gas and its short-lived progenies 218Po, 214Pb, and 214Po were continuously monitored every four hours at the ground level in Jeddah city, Kingdom of Saudi Arabia. The measurements were performed three times every week, starting from November 2014 to October 2015. A method of electrostatic precipitation of positively charged 218Po and 214Po by a positive voltage was applied for determining 222Rn gas concentration. The short-lived 222Rn progeny concentration was determined by using a filter holder connected with the alpha-spectrometric technique. The meteorological parameters (relative air humidity, air temperature, and wind speed) were determined during the measurements of 222Rn and its progeny concentrations. 222Rn gas as well as its short-lived progeny concentration display a daily and seasonal variation with high values in the night and early morning hours as compared to low values at noon and in the afternoon. The observed monthly atmospheric concentrations showed a seasonal trend with the highest values in the autumn/winter season and the lowest values in the spring/summer season. Moreover, and in parallel with alpha-spectrometric measurements, a single filter-holder was used to collect air samples. The deposited activities of 214Pb and the long-lived 222Rn daughter 210Pb on the filter were measured with the gamma spectrometric technique. The measured activity concentrations of 214Pb by both techniques were found to be relatively equal largely. The highest mean seasonally activity concentrations of 210Pb were observed in the autumn/winter season while the lowest mean were observed in the spring/summer season. The mean residence time (MRT) of aerosol particles in the atmospheric air could be estimated from the activity ratios of 210Pb/214Pb. Project supported by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah (Grant No. 291/965/1434).

  1. Climate response to projected changes in short-lived species under an A1B scenario from 2000-2050 in the GISS climate model

    SciTech Connect

    Menon, Surabi; Shindell, Drew T.; Faluvegi, Greg; Bauer, Susanne E.; Koch, Dorothy M.; Unger, Nadine; Menon, Surabi; Miller, Ron L.; Schmidt, Gavin A.; Streets, David G.

    2007-03-26

    We investigate the climate forcing from and response to projected changes in short-lived species and methane under the A1B scenario from 2000-2050 in the GISS climate model. We present a meta-analysis of new simulations of the full evolution of gas and aerosol species and other existing experiments with variations of the same model. The comparison highlights the importance of several physical processes in determining radiative forcing, especially the effect of climate change on stratosphere-troposphere exchange, heterogeneous sulfate-nitrate-dust chemistry, and changes in methane oxidation and natural emissions. However, the impact of these fairly uncertain physical effects is substantially less than the difference between alternative emission scenarios for all short-lived species. The net global mean annual average direct radiative forcing from the short-lived species is .02 W/m{sup 2} or less in our projections, as substantial positive ozone forcing is largely offset by negative aerosol direct forcing. Since aerosol reductions also lead to a reduced indirect effect, the global mean surface temperature warms by {approx}0.07 C by 2030 and {approx}0.13 C by 2050, adding 19% and 17%, respectively, to the warming induced by long-lived greenhouse gases. Regional direct forcings are large, up to 3.8 W/m{sup 2}. The ensemble-mean climate response shows little regional correlation with the spatial pattern of the forcing, however, suggesting that oceanic and atmospheric mixing generally overwhelms the effect of even large localized forcings. Exceptions are the polar regions, where ozone and aerosols may induce substantial seasonal climate changes.

  2. Two-step laser ionization schemes for in-gas laser ionization and spectroscopy of radioactive isotopes

    SciTech Connect

    Kudryavtsev, Yu. Ferrer, R.; Huyse, M.; Van den Bergh, P.; Van Duppen, P.; Vermeeren, L.

    2014-02-15

    The in-gas laser ionization and spectroscopy technique has been developed at the Leuven isotope separator on-line facility for the production and in-source laser spectroscopy studies of short-lived radioactive isotopes. In this article, results from a study to identify efficient optical schemes for the two-step resonance laser ionization of 18 elements are presented.

  3. Seasonal variations in photosynthesis, intrinsic water-use efficiency and stable isotope composition of poplar leaves in a short-rotation plantation.

    PubMed

    Broeckx, L S; Fichot, R; Verlinden, M S; Ceulemans, R

    2014-07-01

    Photosynthetic carbon assimilation and transpirational water loss play an important role in the yield and the carbon sequestration potential of bioenergy-devoted cultures of fast-growing trees. For six poplar (Populus) genotypes in a short-rotation plantation, we observed significant seasonal and genotypic variation in photosynthetic parameters, intrinsic water-use efficiency (WUEi) and leaf stable isotope composition (δ13C and δ18O). The poplars maintained high photosynthetic rates (between 17.8 and 26.9 μmol m(-2) s(-1) depending on genotypes) until late in the season, in line with their fast-growth habit. Seasonal fluctuations were mainly explained by variations in soil water availability and by stomatal limitation upon photosynthesis. Stomatal rather than biochemical limitation was confirmed by the constant intrinsic photosynthetic capacity (Vcmax) during the growing season, closely related to leaf nitrogen (N) content. Intrinsic water-use efficiency scaled negatively with carbon isotope discrimination (Δ13Cbl) and positively with the ratio between mesophyll diffusion conductance (gm) and stomatal conductance. The WUEi-Δ13Cbl relationship was partly influenced by gm. There was a trade-off between WUEi and photosynthetic N-use efficiency, but only when soil water availability was limiting. Our results suggest that seasonal fluctuations in relation to soil water availability should be accounted for in future modelling studies assessing the carbon sequestration potential and the water-use efficiency of woody energy crops.

  4. Seasonal variations in photosynthesis, intrinsic water-use efficiency and stable isotope composition of poplar leaves in a short-rotation plantation

    PubMed Central

    Broeckx, L.S.; Fichot, R.; Verlinden, M.S.; Ceulemans, R.

    2014-01-01

    Photosynthetic carbon assimilation and transpirational water loss play an important role in the yield and the carbon sequestration potential of bioenergy-devoted cultures of fast-growing trees. For six poplar (Populus) genotypes in a short-rotation plantation, we observed significant seasonal and genotypic variation in photosynthetic parameters, intrinsic water-use efficiency (WUEi) and leaf stable isotope composition (δ13C and δ18O). The poplars maintained high photosynthetic rates (between 17.8 and 26.9 μmol m−2 s−1 depending on genotypes) until late in the season, in line with their fast-growth habit. Seasonal fluctuations were mainly explained by variations in soil water availability and by stomatal limitation upon photosynthesis. Stomatal rather than biochemical limitation was confirmed by the constant intrinsic photosynthetic capacity (Vcmax) during the growing season, closely related to leaf nitrogen (N) content. Intrinsic water-use efficiency scaled negatively with carbon isotope discrimination (Δ13Cbl) and positively with the ratio between mesophyll diffusion conductance (gm) and stomatal conductance. The WUEi – Δ13Cbl relationship was partly influenced by gm. There was a trade-off between WUEi and photosynthetic N-use efficiency, but only when soil water availability was limiting. Our results suggest that seasonal fluctuations in relation to soil water availability should be accounted for in future modelling studies assessing the carbon sequestration potential and the water-use efficiency of woody energy crops. PMID:25074859

  5. Instrumental activation analysis of coal and fly ash with thermal and epithermal neutrons and short-lived nuclides

    USGS Publications Warehouse

    Steinnes, E.; Rowe, J.J.

    1976-01-01

    Instrumental neutron activation analysis is applied to the determination of about 25 elements in coals and fly ash by means of nuclides with half-lives of less than 48 h ; thermal and epithermal irradiations are used. The results indicate that epithermal activation is preferable for twelve of the elements (Ga, As, Br, Sr, In, Cs, Ba, La, Sm, Ho, W and U). Data for SRM 1632 (coal) and SRM 1633 (fly ash) compare favorably with the results obtained by other investigators. ?? 1976.

  6. Discovery of Highly Excited Long-Lived Isomers in Neutron-Rich Hafnium and Tantalum Isotopes through Direct Mass Measurements

    SciTech Connect

    Reed, M. W.; Cullen, I. J.; Walker, P. M.; Deo, A. Y.; Kempley, R. S.; Swan, T. P. D.; Litvinov, Yu. A.; Winckler, N.; Blaum, K.; Bosch, F.; Dimopoulou, C.; Farinon, F.; Heil, M.; Knoebel, R.; Kozhuharov, C.; Kurcewicz, J.; Kuzminchuk, N.; Litvinov, S.; Nociforo, C.; Nolden, F.

    2010-10-22

    A study of cooled {sup 197}Au projectile-fragmentation products has been performed with a storage ring. This has enabled metastable nuclear excitations with energies up to 3 MeV, and half-lives extending to minutes or longer, to be identified in the neutron-rich nuclides {sup 183,184,186}Hf and {sup 186,187}Ta. The results support the prediction of a strongly favored isomer region near neutron number 116.

  7. Evidence for a short-lived increase in atmospheric CO2 at the Oligocene/Miocene boundary

    NASA Astrophysics Data System (ADS)

    Reichgelt, T.; D'Andrea, W. J.; Fox, B.

    2015-12-01

    In the earliest Miocene the Antarctic ice sheet retreated substantially following the Mi-1 glaciation event. The relationship between pCO2 and orbital scale climate variations at this time is poorly understood, due to the paucity of pCO2 reconstructions with sufficient temporal resolution. Here, we report a pCO2 reconstruction based on fossil leaf micromorphological properties and supported by δ13C measurements, that indicates that pCO2 increased following the Mi-1 event and remained elevated for approximately 24 kyrs. The fossil leaves analyzed (Lauraceae) and δ13C measurements come from a drill core of annually laminated sediments recovered from a maar lake deposit in southern New Zealand spanning ~100 kyr across the Oligocene/Miocene boundary. The lake had a large and stable anoxic zone, allowing for remarkable preservation of organic material, including exquisitely preserved fossil leaves. The leaf stomatal/epidermal cell ratio (stomatal index) decreased for ~24 kyr during this time period, suggesting increased pCO2. δ13C values of primarily terrestrially sourced lake organic matter decreased by ~4‰ across the same interval, providing further support for an abrupt 24kyr-long increase in pCO2 at this time. By comparison with stomatal conductance and pCO2-induced carbon isotope fractionation in modern land plants, we estimate that the magnitude of the pCO2 increase was between 140 and 220 ppm. These results imply that dynamic variations in pCO2 occurred at precessional timescales during the early Miocene. We are further constraining the magnitude of pCO2 change and quantifying the pCO2 levels by: 1) Analyzing micromorphology and δ13C of close ecological and taxonomical modern analogues to early Miocene New Zealand Lauraceae, to better quantify changes in gas conductance and carbon isotope fractionation in response to recent pCO2 changes; 2) Directly measuring δ13C values and stomatal geometry of fossil leaves, to quantify pCO2 values using a recently

  8. Universal Slow RI-Beam Facility at RIKEN RIBF for Laser Spectroscopy of Short-Lived Nuclei

    SciTech Connect

    Wada, M.; Takamine, A.; Okada, K.; Sonoda, T.; Schury, P.; Kanai, Y.; Kojima, T. M.; Lioubimov, V.; Yamazaki, Y.; Yoshida, A.; Kubo, T.; Iimura, H.; Katayama, I.; Ohtani, S.; Wollnik, H.; Schuessler, H. A.

    2009-03-17

    A universal slow RI-beam facility (SLOWRI) for precision atomic spectroscopy is being built at the RIKEN RI-beam factory. The facility will provide a wide variety of low-energy nuclear ions of all elements produced by projectile fragmentation of high-energy heavy-ion beams and thermalized by an RF-carpet ion guide. At prototype SLOWRI, radioactive Be isotope ions produced at 1 GeV were decelerated and cooled in an ion trap down to 1 {mu}eV by employing laser cooling. The ground state hyperfine structures of {sup 7}Be{sup +} and {sup 11}Be{sup +} were measured accurately by laser microwave double resonance spectroscopy. Measurements of the S{sub 1/2}{yields}P{sub 1/2}, P{sub 3/2} transition frequencies of {sup 7,9,10,11}Be{sup +} ions are also in progress aiming at the study of the nuclear charge radii. Other possible experiment at SLOWRI, such as mass spectroscopy, are also discussed.

  9. Precision Mass Measurements of Short-Lived, Neutron-Rich, R-Process Nuclei About the N=82 Waiting Point

    NASA Astrophysics Data System (ADS)

    Lascar, Daniel David

    This thesis details the precision mass measurements of 33 neutron-rich ground-state nuclei and isomeric states that approach or lie on the proposed rapid neutron capture process (r-process) path. For many of the nuclei measured the work presented here will be the rst direct mass measurements of these nuclei, including 130In, 137Sb, 133I, and 134I. The measurements were made using the Canadian Penning Trap mass spectrometer (CPT), located at the ATLAS heavy ion-linac at Argonne National Laboratory. Ground states and isomers have been measured with the CPT at fractional precisions (δm/m) between 10-7, and 10-8. The nuclei were produced at the new CAlifornium Rare Isotope Breeder Upgrade (CARIBU) to ATLAS. Because nuclear masses are required for measuring neutron separation energies, and neutron separation energies are important inputs in r-process network calculations, precision mass measurements are critical for advancing our knowledge of the r-process. This thesis will give the astrophysical motivation for making these mass measurements, the theoretical background behind ion trapping and mass measurements using ion traps, an explanation of the CPT apparatus, the mass measurements themselves, and the results of those measurements as they pertain to r-process network calculations. Results of these mass measurements show significant shifts in the r-process path over a range of temperatures and neutron densities.

  10. Metabolic adaptations to short-term every-other-day feeding in long-living Ames dwarf mice.

    PubMed

    Brown-Borg, Holly M; Rakoczy, Sharlene

    2013-09-01

    Restrictive dietary interventions exert significant beneficial physiological effects in terms of aging and age-related disease in many species. Every other day feeding (EOD) has been utilized in aging research and shown to mimic many of the positive outcomes consequent with dietary restriction. This study employed long living Ames dwarf mice subjected to EOD feeding to examine the adaptations of the oxidative phosphorylation and antioxidative defense systems to this feeding regimen. Every other day feeding lowered liver glutathione (GSH) concentrations in dwarf and wild type (WT) mice but altered GSH biosynthesis and degradation in WT mice only. The activities of liver OXPHOS enzymes and corresponding proteins declined in WT mice fed EOD while in dwarf animals, the levels were maintained or increased with this feeding regimen. Antioxidative enzymes were differentially affected depending on the tissue, whether proliferative or post-mitotic. Gene expression of components of liver methionine metabolism remained elevated in dwarf mice when compared to WT mice as previously reported however, enzymes responsible for recycling homocysteine to methionine were elevated in both genotypes in response to EOD feeding. The data suggest that the differences in anabolic hormone levels likely affect the sensitivity of long living and control mice to this dietary regimen, with dwarf mice exhibiting fewer responses in comparison to WT mice. These results provide further evidence that dwarf mice may be better protected against metabolic and environmental perturbations which may in turn, contribute to their extended longevity.

  11. Metabolic adaptations to short-term every-other-day feeding in long-living Ames dwarf mice.

    PubMed

    Brown-Borg, Holly M; Rakoczy, Sharlene

    2013-09-01

    Restrictive dietary interventions exert significant beneficial physiological effects in terms of aging and age-related disease in many species. Every other day feeding (EOD) has been utilized in aging research and shown to mimic many of the positive outcomes consequent with dietary restriction. This study employed long living Ames dwarf mice subjected to EOD feeding to examine the adaptations of the oxidative phosphorylation and antioxidative defense systems to this feeding regimen. Every other day feeding lowered liver glutathione (GSH) concentrations in dwarf and wild type (WT) mice but altered GSH biosynthesis and degradation in WT mice only. The activities of liver OXPHOS enzymes and corresponding proteins declined in WT mice fed EOD while in dwarf animals, the levels were maintained or increased with this feeding regimen. Antioxidative enzymes were differentially affected depending on the tissue, whether proliferative or post-mitotic. Gene expression of components of liver methionine metabolism remained elevated in dwarf mice when compared to WT mice as previously reported however, enzymes responsible for recycling homocysteine to methionine were elevated in both genotypes in response to EOD feeding. The data suggest that the differences in anabolic hormone levels likely affect the sensitivity of long living and control mice to this dietary regimen, with dwarf mice exhibiting fewer responses in comparison to WT mice. These results provide further evidence that dwarf mice may be better protected against metabolic and environmental perturbations which may in turn, contribute to their extended longevity. PMID:23832075

  12. Utilization of short- and medium-lived nuclides for the trace-element characterization of food samples

    SciTech Connect

    Chatt, A.; McDowell, L.S.; Pegg, D.L.

    1986-01-01

    Food has long been known to play a key role not only in the health status of human beings but also in their social lives. Relationships between food and physical as well as spiritual well-beings have been cited in ancient Chinese, Greek, and Indian literatures. Modern medicine, curative as well as preventive, values the nutritional aspects of food. In this regard, there exists an increasing interest in estimating the average daily intake of biologically important elements through food. Instrumental neutron activation analysis (INAA) is particularly well suited for the simultaneous determinations of major, minor, and trace elements in both individual food items and composite diets. In the present study, emphasis is placed on the development of reliable and rapid INAA methods for measuring concentrations of ten elements of nutritional interest in food samples.

  13. Constraints on long-lived remnants of neutron star binary mergers from late-time radio observations of short duration gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Metzger, Brian D.; Bower, Geoffrey C.

    2014-01-01

    The coalescence of a binary neutron star (NS) system (an `NS merger' or NSM) may in some cases produce a massive NS remnant that is long lived and, potentially, indefinitely stable to gravitational collapse. Such a remnant has been proposed as an explanation for the late-X-ray emission observed following some short-duration gamma-ray bursts (GRBs) and as possible electromagnetic counterparts to the gravitational wave chirp. A stable NS merger remnant necessarily possesses a large rotational energy ≳1052 erg, the majority of which is ultimately deposited into the surrounding circumburst medium (CBM) at mildly relativistic velocities. We present Very Large Array radio observations of seven short GRBs, some of which possessed temporally extended X-ray emission, on time-scales of ˜1-3 yr following the initial burst. No radio sources were detected, with typical upper limits ˜0.3 mJy at ν = 1.4 GHz. A basic model for the synchrotron emission from the blast wave is used to constrain the presence of a long-lived NSM remnant in each system. Depending on the GRB, our non-detections translate into upper limits on the CBM density n ≲ 3 × 10- 2-3 cm-3 required for consistency with the remnant hypothesis. Our upper limits rule out a long-lived remnant in GRB 050724 and 060505, but cannot rule out such a remnant in other systems due to their lower inferred CMB densities based on afterglow modelling or the lack of such constraints.

  14. Impact of feeding and short-term temperature stress on the content and isotopic signature of fatty acids, sterols, and alcohols in the scleractinian coral Turbinaria reniformis

    NASA Astrophysics Data System (ADS)

    Tolosa, I.; Treignier, C.; Grover, R.; Ferrier-Pagès, C.

    2011-09-01

    This study assesses the combined effect of feeding and short-term thermal stress on various physiological parameters and on the fatty acid, sterol, and alcohol composition of the scleractinian coral Turbinaria reniformis. The compound-specific carbon isotope composition of the lipids was also measured. Under control conditions (26°C), feeding with Artemia salina significantly increased the symbiont density and chlorophyll content and the growth rates of the corals. It also doubled the concentrations of almost all fatty acid (FA) compounds and increased the n-alcohol and sterol contents. δ13C results showed that the feeding enhancement of FA concentrations occurred either via a direct pathway, for one of the major polyunsaturated fatty acid (PUFA) compounds of the food (18:3n-3 FA), or via an enhancement of photosynthate transfer (indirect pathway), for the other coral FAs. Cholesterol (C27Δ5) was also directly acquired from the food. Thermal stress (31°C) affected corals, but differently according to their feeding status. Chlorophyll, protein content, and maximal photosynthetic efficiency of photosystem II (PSII) decreased to a greater extent in starved corals. In such corals, FA concentrations were reduced by 33%, (especially C16, C18 FAs, and n-3 PUFA) and the sterol content by 27% (especially the C28∆5,22 and C28∆5). The enrichment in the δ13C signature of the storage and structural FAs suggests that they were the main compounds respired during the stress to maintain the coral metabolism. Thermal stress had less effect on the lipid concentrations of fed corals, as only FA levels were reduced by 13%, with no major changes in their isotope carbon signatures. In conclusion, feeding plays an essential role in sustaining T. reniformis metabolism during the thermal stress.

  15. The age related markers lipofuscin and apoptosis show different genetic architecture by QTL mapping in short-lived Nothobranchius fish

    PubMed Central

    Ng'oma, Enoch; Reichwald, Kathrin; Dorn, Alexander; Wittig, Michael; Balschun, Tobias; Franke, Andre; Platzer, Matthias; Cellerino, Allesandro

    2014-01-01

    Annual fish of the genus Nothobranchius show large variations in lifespan and expression of age-related phenotypes between closely related populations. We studied N. kadleci and its sister species N. furzeri GRZ strain, and found that N.kadleci is longer-lived than the N. furzeri. Lipofuscin and apoptosis measured in the liver increased with age in N. kadleci with different profiles: lipofuscin increased linearly, while apoptosis declined in the oldest animals. More lipofuscin (P < 0.001) and apoptosis (P < 0.001) was observed in N. furzeri than in N. kadleci at 16w age. Lipofuscin and apoptotic cells were then quantified in hybrids from the mating of N. furzeri to N. kadleci. F1 individuals showed heterosis for lipofuscin but additive effects for apoptosis. These two age-related phenotypes were not correlated in F2 hybrids. Quantitative trait loci analysis of 287 F2 fish using 237 markers identified two QTL accounting for 10% of lipofuscin variance (P < 0.001) with overdominance effect. Apoptotic cells revealed three significant- and two suggestive QTL explaining 19% of variance (P < 0.001), showing additive and dominance effects, and two interacting loci. Our results show that lipofuscin and apoptosis are markers of different age-dependent biological processes controlled by different genetic mechanisms. PMID:25093339

  16. Short lived 36Cl and its decay products 36Ar and 36S in the early solar system

    NASA Astrophysics Data System (ADS)

    Turner, G.; Crowther, S. A.; Burgess, R.; Gilmour, J. D.; Kelley, S. P.; Wasserburg, G. J.

    2013-12-01

    Variable excesses of 36S have previously been reported in sodalite in the Allende and Ningqiang meteorites and used to infer the presence of 36Cl in the early solar system. Until now no unambiguous evidence of the major decay product, 36Ar (98%), has been found. Using low fluence fast neutron activation we have measured small amounts of 36Ar in the Allende sodalite Pink Angel, corresponding to 36Cl/35Cl = (1.9 ± 0.5) × 10-8. This is a factor of 200 lower than the highest value inferred from 36S excesses in sodalite. High resolution I-Xe analyses confirm that the sodalite formed between 4561 and 4558 Ma ago. The core of Pink Angel sodalite yielded a precise formation age of 4559.4 ± 0.6 Ma. Deposition of sodalite containing live 36Cl, seven million years or so after the formation of the CAI, appears to require a local production mechanism involving intense neutron irradiation within the solar nebula. The constraint imposed by the near absence of neutron induced 128Xe is most easily satisfied if the 36Cl were produced in a fluid precursor of the sodalite. The low level of 36Ar could be accounted for as a result of residual in-situ36Cl decay, up to 1-2 Ma after formation of the sodalite, and/or later diffusive loss, in line with the low activation energy for Ar diffusion in sodalite.

  17. Short Communication: Viral Suppression Is Associated with Increased Likelihood of Colorectal Cancer Screening Among Persons Living with HIV/AIDS.

    PubMed

    Burkholder, Greer A; Tamhane, Ashutosh R; Appell, Lauren E; Willig, James H; Saag, Michael S; Raper, James L; Westfall, Andrew O; Mugavero, Michael J

    2015-05-01

    With improved survival and aging, more persons living with HIV/AIDS (PLWHA) are at risk for colorectal cancer (CRC). This retrospective longitudinal study evaluated patient characteristics associated with CRC screening in our HIV cohort. Patients were followed beginning at age 50 years during a study period from January 1, 2003 to December 31, 2010 (n=265). During a median follow-up time of 1.7 years, only 30% of patients underwent CRC screening. The majority of screened patients received endoscopic screening (colonoscopy, 86%; sigmoidoscopy, 8%); among these patients, results were available for 68/75, and adenomatous polyps were found in 13%. No cases of CRC were reported. Among unscreened patients, only 23% had an external primary care provider, indicating an HIV provider was the expected source for CRC screening referral in the majority. Patients with time-varying suppressed HIV viral load were more likely to receive screening (HRadjusted=1.74; 95% CI: 1.05-2.87), independent of CD4 count. Our findings suggest HIV providers are more likely to address non-HIV-related healthcare maintenance when HIV is controlled. In addition, a significant number of neoplastic lesions are likely being missed in PLWHA who have not been screened for CRC. Provision of evidence-based preventive care in addition to HIV care is required for the aging population of PLWHA.

  18. Maintenance of somatic tissue regeneration with age in short- and long-lived species of sea urchins.

    PubMed

    Bodnar, Andrea G; Coffman, James A

    2016-08-01

    Aging in many animals is characterized by a failure to maintain tissue homeostasis and the loss of regenerative capacity. In this study, the ability to maintain tissue homeostasis and regenerative potential was investigated in sea urchins, a novel model to study longevity and negligible senescence. Sea urchins grow indeterminately, regenerate damaged appendages and reproduce throughout their lifespan and yet different species are reported to have very different life expectancies (ranging from 4 to more than 100 years). Quantitative analyses of cell proliferation and apoptosis indicated a low level of cell turnover in tissues of young and old sea urchins of species with different lifespans (Lytechinus variegatus, Strongylocentrotus purpuratus and Mesocentrotus franciscanus). The ability to regenerate damaged tissue was maintained with age as assessed by the regrowth of amputated spines and tube feet (motor and sensory appendages). Expression of genes involved in cell proliferation (pcna), telomere maintenance (tert) and multipotency (seawi and vasa) was maintained with age in somatic tissues. Immunolocalization of the Vasa protein to areas of the tube feet, spines, radial nerve, esophagus and a sub-population of circulating coelomocytes suggests the presence of multipotent cells that may play a role in normal tissue homeostasis and the regenerative potential of external appendages. The results indicate that regenerative potential was maintained with age regardless of lifespan, contrary to the expectation that shorter lived species would invest less in maintenance and repair. PMID:27095483

  19. Intramolecular sensitization of americium luminescence in solution: Shining light on short-lived forbidden 5f transitions

    DOE PAGESBeta

    Sturzbecher-Hoehne, M.; Yang, P.; D'Aleo, A.; Abergel, R. J.

    2016-03-10

    In this study, the photophysical properties and solution thermodynamics of water soluble trivalent americium (AmIII) complexes formed with multidentate chromophore-bearing ligands, 3,4,3-LI(1,2-HOPO), Enterobactin, and 5-LIO(Me-3,2-HOPO), were investigated. The three chelators were shown to act as antenna chromophores for AmIII, generating sensitized luminescence emission from the metal upon complexation, with very short lifetimes ranging from 33 to 42 ns and low luminescence quantum yields (10–3 to 10–2%), characteristic of Near Infra-Red emitters in similar systems. The specific emission peak of AmIII assigned to the 5D1 → 7F1 f–f transition was exploited to characterize the high proton-independent stability of the complex formedmore » with the most efficient sensitizer 3,4,3-LI(1,2-HOPO), with a log β110 = 20.4 ± 0.2 value. In addition, the optical and solution thermodynamic features of these AmIII complexes, combined with density functional theory calculations, were used to probe the influence of electronic structure on coordination properties across the f-element series and to gain insight into ligand field effects.« less

  20. Intramolecular sensitization of americium luminescence in solution: shining light on short-lived forbidden 5f transitions.

    PubMed

    Sturzbecher-Hoehne, M; Yang, P; D'Aléo, A; Abergel, R J

    2016-06-14

    The photophysical properties and solution thermodynamics of water soluble trivalent americium (Am(III)) complexes formed with multidentate chromophore-bearing ligands, 3,4,3-LI(1,2-HOPO), Enterobactin, and 5-LIO(Me-3,2-HOPO), were investigated. The three chelators were shown to act as antenna chromophores for Am(III), generating sensitized luminescence emission from the metal upon complexation, with very short lifetimes ranging from 33 to 42 ns and low luminescence quantum yields (10(-3) to 10(-2)%), characteristic of Near Infra-Red emitters in similar systems. The specific emission peak of Am(III) assigned to the (5)D1 → (7)F1 f-f transition was exploited to characterize the high proton-independent stability of the complex formed with the most efficient sensitizer 3,4,3-LI(1,2-HOPO), with a log β110 = 20.4 ± 0.2 value. In addition, the optical and solution thermodynamic features of these Am(III) complexes, combined with density functional theory calculations, were used to probe the influence of electronic structure on coordination properties across the f-element series and to gain insight into ligand field effects. PMID:26961598

  1. Intramolecular sensitization of americium luminescence in solution: Shining light on short-lived forbidden 5f transitions

    SciTech Connect

    Sturzbecher-Hoehne, M.; Yang, P.; D'Aleo, A.; Abergel, R. J.

    2016-01-01

    In this study, the photophysical properties and solution thermodynamics of water soluble trivalent americium (AmIII) complexes formed with multidentate chromophore-bearing ligands, 3,4,3-LI(1,2-HOPO), Enterobactin, and 5-LIO(Me-3,2-HOPO), were investigated. The three chelators were shown to act as antenna chromophores for AmIII, generating sensitized luminescence emission from the metal upon complexation, with very short lifetimes ranging from 33 to 42 ns and low luminescence quantum yields (10–3 to 10–2%), characteristic of Near Infra-Red emitters in similar systems. The specific emission peak of AmIII assigned to the 5D17F1 f–f transition was exploited to characterize the high proton-independent stability of the complex formed with the most efficient sensitizer 3,4,3-LI(1,2-HOPO), with a log β110 = 20.4 ± 0.2 value. In addition, the optical and solution thermodynamic features of these AmIII complexes, combined with density functional theory calculations, were used to probe the influence of electronic structure on coordination properties across the f-element series and to gain insight into ligand field effects.

  2. Quantitative survival model for short-term survival after adult-to-adult living donor liver transplantation.

    PubMed

    Tsunematsu, Ichiro; Ogura, Yasuhiro; Inoue, Kayoko; Koizumi, Akio; Tanigawa, Nobuhiko; Tanaka, Koichi

    2006-06-01

    Adult-to-adult living donor liver transplantation (ALDLT) has been accepted as an important option for end-stage liver disease, but information regarding the risk factors remains fragmentary. We aimed to establish a predictive model for 90-day survival. In the first step, a total of 286 cases who had received primary ALDLT using a right lobe graft between 1998 and 2004 were randomly divided into 2 cohorts at a ratio of 2:1 (191 vs. 95 recipients). The larger cohort of patients was used to develop a model. The outcome was defined as 90-day survival, and a total of 39 preoperative and operative variables, including the period of surgery (1998-2001 vs. 2002-2004), were included using Cox's proportional hazard regression model. Two mismatches of human leukocyte antigen (HLA) type DR (hazard ratio [HR] = 4.45; confidence interval [CI] = 1.96-10.1), log(e)[blood loss volume] (HR = 2.43; CI = 1.64-3.60), period of surgery (1998-2001 vs. 2002-2004) (HR = 2.41; CI = 1.04-5.57), and log(e)[serum C-reactive protein or CRP] (HR = 1.64; CI = 1.13-2.38) were found to be independent risk factors. In the second step, we tried to establish a realistic survival model. In this step, we created 2 models, 1 that used all 4 variables (model 1) and 1 (model 2) in which blood loss volume was replaced with the past history of upper abdominal surgery and Model for End-Stage Liver Disease (MELD) score (> or =25), both of which showed associations with blood loss volume. These models were applied to the smaller cohort of 95 patients. Receiver operating characteristic analyses demonstrated that both models showed similar significant c-statistics (0.63 and 0.62, respectively). In conclusion, model 2 can provide a rough estimation of the 90-day survival after ALDLT.

  3. Impacts of Pristine and Transformed Ag and Cu Engineered Nanomaterials on Surficial Sediment Microbial Communities Appear Short-Lived.

    PubMed

    Moore, Joe D; Stegemeier, John P; Bibby, Kyle; Marinakos, Stella M; Lowry, Gregory V; Gregory, Kelvin B

    2016-03-01

    Laboratory-based studies have shown that many soluble metal and metal oxide engineered nanomaterials (ENM) exert strong toxic effects on microorganisms. However, laboratory-based studies lack the complexity of natural systems and often use "as manufactured" ENMs rather than more environmentally relevant transformed ENMs, leaving open the question of whether natural ligands and seasonal variation will mitigate ENM impacts. Because ENMs will accumulate in subaquatic sediments, we examined the effects of pristine and transformed Ag and Cu ENMs on surficial sediment microbial communities in simulated freshwater wetlands. Five identical mesocosms were dosed through the water column with either Ag(0), Ag2S, CuO or CuS ENMs (nominal sizes of 4.67 ± 1.4, 18.1 ± 3.2, 31.1 ± 12, and 12.4 ± 4.1, respectively) or Cu(2+). Microbial communities were examined at 0, 7, 30, 90, 180, and 300 d using qPCR and high-throughput 16S rRNA gene sequencing. Results suggest differential short-term impacts of Ag(0) and Ag2S, similarities between CuO and CuS, and differences between Cu ENMs and Cu(2+). PICRUSt-predicted metagenomes displayed differential effects of Ag treatments on photosynthesis and of Cu treatments on methane metabolism. By 300 d, all metrics pointed to reconvergence of ENM-dosed mesocosm microbial community structure and composition, suggesting that the long-term microbial community impacts from a pulse of Ag or Cu ENMs are limited. PMID:26841726

  4. The Bruininks-Oseretsky Test of Motor Proficiency-Short Form is reliable in children living in remote Australian Aboriginal communities

    PubMed Central

    2013-01-01

    Background The Lililwan Project is the first population-based study to determine Fetal Alcohol Spectrum Disorders (FASD) prevalence in Australia and was conducted in the remote Fitzroy Valley in North Western Australia. The diagnostic process for FASD requires accurate assessment of gross and fine motor functioning using standardised cut-offs for impairment. The Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2) is a norm-referenced assessment of motor function used worldwide and in FASD clinics in North America. It is available in a Complete Form with 53 items or a Short Form with 14 items. Its reliability in measuring motor performance in children exposed to alcohol in utero or living in remote Australian Aboriginal communities is unknown. Methods A prospective inter-rater and test-retest reliability study was conducted using the BOT-2 Short Form. A convenience sample of children (n = 30) aged 7 to 9 years participating in the Lililwan Project cohort (n = 108) study, completed the reliability study. Over 50% of mothers of Lililwan Project children drank alcohol during pregnancy. Two raters simultaneously scoring each child determined inter-rater reliability. Test-retest reliability was determined by assessing each child on a second occasion using predominantly the same rater. Reliability was analysed by calculating Intra-Class correlation Coefficients, ICC(2,1), Percentage Exact Agreement (PEA) and Percentage Close Agreement (PCA) and measures of Minimal Detectable Change (MDC) were calculated. Results Thirty Aboriginal children (18 male, 12 female: mean age 8.8 years) were assessed at eight remote Fitzroy Valley communities. The inter-rater reliability for the BOT-2 Short Form score sheet outcomes ranged from 0.88 (95%CI, 0.77 – 0.94) to 0.92 (95%CI, 0.84 – 0.96) indicating excellent reliability. The test-retest reliability (median interval between tests being 45.5 days) for the BOT-2 Short Form score sheet outcomes ranged from

  5. International intercomparison of measuring instruments for radon/thoron gas and radon short-lived daughter products in the NRPI Prague.

    PubMed

    Jílek, K; Hýža, M; Kotík, L; Thomas, J; Tomášek, L

    2014-07-01

    During the 7th European Conference on Protection Against Radon at Home and at Work held in the autumn of 2013 in Prague, the second intercomparison of measuring instruments for radon and its short-lived decay products and the first intercomparison of radon/thoron gas discriminative passive detectors in mix field of radon/thoron were organised by and held at the Natural Radiation Division of the National Radiation Protection Institute (NRPI) in Prague. In total, 14 laboratories from 11 different countries took part in the 2013 NRPI intercomparison. They submitted both continuous monitors for the measurement of radon gas and equivalent equilibrium radon concentration in a big NRPI chamber (48 m3) and sets of passive detectors including radon/thoron discriminative for the measurement of radon gas in the big chamber and thoron gas in a small thoron chamber (150 dm3).

  6. Design a 10 kJ IS Mather Type Plasma Focus for Solid Target Activation to Produce Short-Lived Radioisotopes 12C(d,n)13N

    NASA Astrophysics Data System (ADS)

    Sadat Kiai, S. M.; Adlparvar, S.; Sheibani, S.; Elahi, M.; Safarien, A.; Farhangi, S.; Zirak, A. R.; Alhooie, S.; Mortazavi, B. N.; Khalaj, M. M.; Khanchi, A. R.; Dabirzadeh, A. A.; Kashani, A.; Zahedi, F.

    2010-10-01

    A 10 kJ (15 kV, 88 μF) IS (Iranian Sun) Mather type plasma focus device has been studied to determine the activity of a compound exogenous carbon solid target through 12C(d,n)13N nuclear reaction. The produced 13N is a short-lived radioisotope with a half-life of 9.97 min and threshold energy of 0.28 MeV. The results indicate that energetic deuterons impinging on the solid target can produce yield of = 6.7 × 10-5 with an activity of A = 6.8 × 104 Bq for one plasma focus shut and A ν = 4 × 105 Bq for 6 shut per mint when the projectile maximum deuterons energy is E max = 3 MeV.

  7. Seasonal phenology of interactions involving short-lived annual plants, a multivoltine herbivore and its endoparasitoid wasp.

    PubMed

    Fei, Minghui; Gols, Rieta; Harvey, Jeffrey A

    2014-01-01

    Spatial-temporal realism is often missing in many studies of multitrophic interactions, which are conducted at a single time frame and/or involving interactions between insects with a single species of plant. In this scenario, an underlying assumption is that the host-plant species is ubiquitous throughout the season and that the insects always interact with it. We studied interactions involving three naturally occurring wild species of cruciferous plants, Brassica rapa, Sinapis arvensis and Brassica nigra, that exhibit different seasonal phenologies, and a multivoltine herbivore, the large cabbage white butterfly, Pieris brassicae, and its gregarious endoparasitoid wasp, Cotesia glomerata. The three plants have very short life cycles. In central Europe, B. rapa grows in early spring, S. arvensis in late spring and early summer, and B. nigra in mid to late summer. P. brassicae generally has three generations per year, and C. glomerata at least two. This means that different generations of the insects must find and exploit different plant species that may differ in quality and which may be found some distance from one another. Insects were either reared on each of the three plant species for three successive generations or shifted between generations from B. rapa to S. arvensis to B. nigra. Development time from neonate to pupation and pupal fresh mass were determined in P. brassicae and egg-to-adult development time and body mass in C. glomerata. Overall, herbivores performed marginally better on S. arvensis and B. nigra plants than on B. rapa plants. Parasitoids performance was closely tailored with that of the host. Irrespective as to whether the insects were shifted to a new plant in successive generations or not, development time of P. brassicae and C. glomerata decreased dramatically over time. Our results show that there were some differences in insect development on different plant species and when transferred from one species to another. However, all three

  8. The short-lived signaling state of the photoactive yellow protein photoreceptor revealed by combined structural probes.

    PubMed

    Ramachandran, Pradeep L; Lovett, Janet E; Carl, Patrick J; Cammarata, Marco; Lee, Jae Hyuk; Jung, Yang Ouk; Ihee, Hyotcherl; Timmel, Christiane R; van Thor, Jasper J

    2011-06-22

    The signaling state of the photoactive yellow protein (PYP) photoreceptor is transiently developed via isomerization of its blue-light-absorbing chromophore. The associated structural rearrangements have large amplitude but, due to its transient nature and chemical exchange reactions that complicate NMR detection, its accurate three-dimensional structure in solution has been elusive. Here we report on direct structural observation of the transient signaling state by combining double electron electron resonance spectroscopy (DEER), NMR, and time-resolved pump-probe X-ray solution scattering (TR-SAXS/WAXS). Measurement of distance distributions for doubly spin-labeled photoreceptor constructs using DEER spectroscopy suggests that the signaling state is well ordered and shows that interspin-label distances change reversibly up to 19 Å upon illumination. The SAXS/WAXS difference signal for the signaling state relative to the ground state indicates the transient formation of an ordered and rearranged conformation, which has an increased radius of gyration, an increased maximum dimension, and a reduced excluded volume. Dynamical annealing calculations using the DEER derived long-range distance restraints in combination with short-range distance information from (1)H-(15)N HSQC perturbation spectroscopy give strong indication for a rearrangement that places part of the N-terminal domain in contact with the exposed chromophore binding cleft while the terminal residues extend away from the core. Time-resolved global structural information from pump-probe TR-SAXS/WAXS data supports this conformation and allows subsequent structural refinement that includes the combined energy terms from DEER, NMR, and SAXS/WAXS together. The resulting ensemble simultaneously satisfies all restraints, and the inclusion of TR-SAXS/WAXS effectively reduces the uncertainty arising from the possible spin-label orientations. The observations are essentially compatible with reduced folding of the

  9. Seasonal phenology of interactions involving short-lived annual plants, a multivoltine herbivore and its endoparasitoid wasp.

    PubMed

    Fei, Minghui; Gols, Rieta; Harvey, Jeffrey A

    2014-01-01

    Spatial-temporal realism is often missing in many studies of multitrophic interactions, which are conducted at a single time frame and/or involving interactions between insects with a single species of plant. In this scenario, an underlying assumption is that the host-plant species is ubiquitous throughout the season and that the insects always interact with it. We studied interactions involving three naturally occurring wild species of cruciferous plants, Brassica rapa, Sinapis arvensis and Brassica nigra, that exhibit different seasonal phenologies, and a multivoltine herbivore, the large cabbage white butterfly, Pieris brassicae, and its gregarious endoparasitoid wasp, Cotesia glomerata. The three plants have very short life cycles. In central Europe, B. rapa grows in early spring, S. arvensis in late spring and early summer, and B. nigra in mid to late summer. P. brassicae generally has three generations per year, and C. glomerata at least two. This means that different generations of the insects must find and exploit different plant species that may differ in quality and which may be found some distance from one another. Insects were either reared on each of the three plant species for three successive generations or shifted between generations from B. rapa to S. arvensis to B. nigra. Development time from neonate to pupation and pupal fresh mass were determined in P. brassicae and egg-to-adult development time and body mass in C. glomerata. Overall, herbivores performed marginally better on S. arvensis and B. nigra plants than on B. rapa plants. Parasitoids performance was closely tailored with that of the host. Irrespective as to whether the insects were shifted to a new plant in successive generations or not, development time of P. brassicae and C. glomerata decreased dramatically over time. Our results show that there were some differences in insect development on different plant species and when transferred from one species to another. However, all three

  10. The short-lived signaling state of the photoactive yellow protein photoreceptor revealed by combined structural probes.

    PubMed

    Ramachandran, Pradeep L; Lovett, Janet E; Carl, Patrick J; Cammarata, Marco; Lee, Jae Hyuk; Jung, Yang Ouk; Ihee, Hyotcherl; Timmel, Christiane R; van Thor, Jasper J

    2011-06-22

    The signaling state of the photoactive yellow protein (PYP) photoreceptor is transiently developed via isomerization of its blue-light-absorbing chromophore. The associated structural rearrangements have large amplitude but, due to its transient nature and chemical exchange reactions that complicate NMR detection, its accurate three-dimensional structure in solution has been elusive. Here we report on direct structural observation of the transient signaling state by combining double electron electron resonance spectroscopy (DEER), NMR, and time-resolved pump-probe X-ray solution scattering (TR-SAXS/WAXS). Measurement of distance distributions for doubly spin-labeled photoreceptor constructs using DEER spectroscopy suggests that the signaling state is well ordered and shows that interspin-label distances change reversibly up to 19 Å upon illumination. The SAXS/WAXS difference signal for the signaling state relative to the ground state indicates the transient formation of an ordered and rearranged conformation, which has an increased radius of gyration, an increased maximum dimension, and a reduced excluded volume. Dynamical annealing calculations using the DEER derived long-range distance restraints in combination with short-range distance information from (1)H-(15)N HSQC perturbation spectroscopy give strong indication for a rearrangement that places part of the N-terminal domain in contact with the exposed chromophore binding cleft while the terminal residues extend away from the core. Time-resolved global structural information from pump-probe TR-SAXS/WAXS data supports this conformation and allows subsequent structural refinement that includes the combined energy terms from DEER, NMR, and SAXS/WAXS together. The resulting ensemble simultaneously satisfies all restraints, and the inclusion of TR-SAXS/WAXS effectively reduces the uncertainty arising from the possible spin-label orientations. The observations are essentially compatible with reduced folding of the

  11. Short-lived species detection of nitrous acid by external-cavity quantum cascade laser based quartz-enhanced photoacoustic absorption spectroscopy

    SciTech Connect

    Yi, Hongming; Maamary, Rabih; Fertein, Eric; Chen, Weidong; Gao, Xiaoming; Sigrist, Markus W.

    2015-03-09

    Spectroscopic detection of short-lived gaseous nitrous acid (HONO) at 1254.85 cm{sup −1} was realized by off-beam coupled quartz-enhanced photoacoustic spectroscopy (QEPAS) in conjunction with an external cavity quantum cascade lasers (EC-QCL). High sensitivity monitoring of HONO was performed within a very small gas-sample volume (of ∼40 mm{sup 3}) allowing a significant reduction (of about 4 orders of magnitude) of air sampling residence time which is highly desired for accurate quantification of chemically reactive short-lived species. Calibration of the developed QEPAS-based HONO sensor was carried out by means of lab-generated HONO samples whose concentrations were determined by direct absorption spectroscopy involving a ∼109.5 m multipass cell and a distributed feedback QCL. A minimum detection limit (MDL) of 66 ppbv (1 σ) HONO was achieved at 70 mbar using a laser output power of 50 mW and 1 s integration time, which corresponded to a normalized noise equivalent absorption coefficient of 3.6 × 10{sup −8 }cm{sup −1} W/Hz{sup 1/2}. This MDL was down to 7 ppbv at the optimal integration time of 150 s. The corresponding 1σ minimum detected absorption coefficient is ∼1.1 × 10{sup −7 }cm{sup −1} (MDL ∼ 3 ppbv) in 1 s and ∼1.1 × 10{sup −8 }cm{sup −1} (MDL ∼ 330 pptv) in 150 s, respectively, with 1 W laser power.

  12. Climate impacts of short-lived climate forcers versus CO2 from biodiesel: a case of the EU on-road sector.

    PubMed

    Lund, Marianne T; Berntsen, Terje K; Fuglestvedt, Jan S

    2014-12-16

    Biofuels are proposed to play an important role in several mitigation strategies to meet future CO2 emission targets for the transport sector but remain controversial due to significant uncertainties in net impacts on environment, society, and climate. A switch to biofuels can also affect short-lived climate forcers (SLCFs), which provide significant contributions to the net climate impact of transportation. We quantify the radiative forcing (RF) and global-mean temperature response over time to EU on-road fossil diesel SLCFs and the impact of 20% (B20) and 100% (B100) replacement of fossil diesel by biodiesel. SLCFs are compared to impacts of on-road CO2 using different approaches from existing literature to account for biodiesel CO2. Given the best estimates for changes in emissions when replacing fossil diesel with biodiesel, the net positive RF from EU on-road fossil diesel SLCFs of 3.4 mW/m(2) is reduced by 15% and 80% in B20 and B100, respectively. Over time the warming of SLCFs is likely small compared to biodiesel CO2 impacts. However, SLCFs may be relatively more important for the total warming than in the fossil fuel case if biodiesel from feedstock with very short rotation periods and low land-use-change impacts replaces a high fraction of fossil diesel.

  13. Oxygen Isotopes in Meteorites

    NASA Astrophysics Data System (ADS)

    Clayton, R. N.

    2003-12-01

    et al., 1996). In their paper reporting the discovery of 18O in the Earth's atmosphere, Giauque and Johnston (1929) refer to nonuniform distribution of oxygen isotopes as a "remote possibility," whereas Manian et al. (1934) sought to find variations in oxygen isotope abundances in meteorites as evidence for an origin outside the solar system.In addition to the abundance variations due to nuclear processes, there are important isotopic variations produced within molecular clouds, the precursors to later star-formation. The most important process is isotopic self-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 wavelength range 90-100 nm. The reaction proceeds by a predissociation mechanism, in which the excited electronic state lives long enough to have well-defined vibrational and rotational energy levels. As a consequence, the three isotopic species - C16O, C17O, and C18O - absorb at different wavelengths, corresponding to the isotope shift in vibrational frequencies. Because of their different number densities, the abundant C16O becomes optically thick in the outermost part of the cloud (nearest to the external source of UV radiation), while the rare C17O and C18O remain optically thin, and hence dissociate at a greater rate in the cloud interior. The differences in chemical reactivity between C16O molecules and 17O and 18O atoms may lead to isotopically selective reaction products. This scenario has been suggested to explain meteoritic isotope patterns, as discussed below (Yurimoto and Kuramoto, 2002).Stable isotope abundances in meteoritic material provide an opportunity to evaluate the thoroughness of mixing of isotopes of diverse stellar sources. Molybdenum presents a good test case: it has seven stable isotopes, derived from at least three

  14. Half-lives and branchings for {beta}-delayed neutron emission for neutron-rich Co-Cu isotopes in the r-process

    SciTech Connect

    Hosmer, P.; Estrade, A.; Montes, F.; Ouellette, M.; Pellegrini, E.; Schatz, H.; Aprahamian, A.; Arndt, O.; Pfeiffer, B.; Clement, R. R. C.; Mueller, W. F.; Morton, A. C.; Pereira, J.; Santi, P.; Steiner, M.; Stolz, A.; Farouqi, K.; Kratz, K.-L.; Liddick, S. N.; Mantica, P. F.

    2010-08-15

    The {beta} decays of very neutron-rich nuclides in the Co-Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL {beta}-counting station in conjunction with the neutron detector NERO. We measured the branchings for {beta}-delayed neutron emission (P{sub n} values) for {sup 74}Co (18{+-}15%) and {sup 75-77}Ni (10{+-}2.8%, 14{+-}3.6%, and 30{+-}24%, respectively) for the first time, and remeasured the P{sub n} values of {sup 77-79}Cu, {sup 79,81}Zn, and {sup 82}Ga. For {sup 77-79}Cu and for {sup 81}Zn we obtain significantly larger P{sub n} values compared to previous work. While the new half-lives for the Ni isotopes from this experiment had been reported before, we present here in addition the first half-life measurements of {sup 75}Co (30{+-}11 ms) and {sup 80}Cu (170{sub -50}{sup +110} ms). Our results are compared with theoretical predictions, and their impact on various types of models for the astrophysical rapid neutron-capture process (r-process) is explored. We find that with our new data, the classical r-process model is better able to reproduce the A=78-80 abundance pattern inferred from the solar abundances. The new data also influence r-process models based on the neutrino-driven high-entropy winds in core collapse supernovae.

  15. The rare isotope accelerator (RIA) facility project

    SciTech Connect

    Christoph Leemann

    2000-08-01

    The envisioned Rare-Isotope Accelerator (RIA) facility would add substantially to research opportunities for nuclear physics and astrophysics by combining increased intensities with a greatly expanded variety of high-quality rare-isotope beams. A flexible superconducting driver linac would provide 100 kW, 400 MeV/nucleon beams of any stable isotope from hydrogen to uranium onto production targets. Combinations of projectile fragmentation, target fragmentation, fission, and spallation would produce the needed broad assortment of short-lived secondary beams. This paper describes the project's background, purpose, and status, the envisioned facility, and the key subsystem, the driver linac. RIA's scientific purposes are to advance current theoretical models, reveal new manifestations of nuclear behavior, and probe the limits of nuclear existence [3]. Figures 1 and 2 show, respectively, examples of RIA research opportunities and the yields projected for pursuing them. Figure 3 outlines a conceptual approach for delivering the needed beams.

  16. Chronic parasitic infection maintains high frequencies of short-lived Ly6C+CD4+ effector T cells that are required for protection against re-infection.

    PubMed

    Peters, Nathan C; Pagán, Antonio J; Lawyer, Phillip G; Hand, Timothy W; Henrique Roma, Eric; Stamper, Lisa W; Romano, Audrey; Sacks, David L

    2014-12-01

    In contrast to the ability of long-lived CD8(+) memory T cells to mediate protection against systemic viral infections, the relationship between CD4(+) T cell memory and acquired resistance against infectious pathogens remains poorly defined. This is especially true for T helper 1 (Th1) concomitant immunity, in which protection against reinfection coincides with a persisting primary infection. In these situations, pre-existing effector CD4 T cells generated by ongoing chronic infection, not memory cells, may be essential for protection against reinfection. We present a systematic study of the tissue homing properties, functionality, and life span of subsets of memory and effector CD4 T cells activated in the setting of chronic Leishmania major infection in resistant C57Bl/6 mice. We found that pre-existing, CD44(+)CD62L(-)T-bet(+)Ly6C+ effector (T(EFF)) cells that are short-lived in the absence of infection and are not derived from memory cells reactivated by secondary challenge, mediate concomitant immunity. Upon adoptive transfer and challenge, non-dividing Ly6C(+) T(EFF) cells preferentially homed to the skin, released IFN-γ, and conferred protection as compared to CD44(+)CD62L(-)Ly6C(-) effector memory or CD44(+)CD62L(+)Ly6C(-) central memory cells. During chronic infection, Ly6C(+) T(EFF) cells were maintained at high frequencies via reactivation of T(CM) and the T(EFF) themselves. The lack of effective vaccines for many chronic diseases may be because protection against infectious challenge requires the maintenance of pre-existing T(EFF) cells, and is therefore not amenable to conventional, memory inducing, vaccination strategies.

  17. Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and South-East Asia during 2009-2013

    NASA Astrophysics Data System (ADS)

    Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

    2013-11-01

    Short-lived organic brominated compounds make up a significant part (~20%) of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLS-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ~100 ppb O3 corresponding to the extra-tropical tropopause layer.

  18. Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and Southeast Asia during 2009-2013

    NASA Astrophysics Data System (ADS)

    Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

    2014-04-01

    Short-lived organic brominated compounds make up a significant part of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five very short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLB-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ∼100 ppb O3 corresponding to the extra-tropical tropopause layer.

  19. Composition and Trends of Short-Lived Trace Gases in the UT/LS over Europe Observed by the CARIBIC Aircraft

    NASA Astrophysics Data System (ADS)

    Baker, A. K.; Brenninkmeijer, C. A.; Oram, D. E.; O'Sullivan, D. A.; Slemr, F.; Schuck, T. J.

    2009-12-01

    The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) involves the monthly deployment of an instrument container equipped to make atmospheric measurements from aboard a commercial airliner, and has operated since 2005 from aboard a Lufthansa Airbus 340-600 . Measurements from the container include in-situ trace gas and aerosol analyses and the collection of aerosol and whole air samples for post-flight laboratory analysis. Measurements made from the sampling flasks include greenhouse gas (GHG), halocarbon and nonmethane hydrocarbon (NMHC) analysis. CARIBIC flights originate in Frankfurt, Germany with routes to India, East Asia, South America, North America and Africa, and typical aircraft cruising altitudes of 10-12km allow for the monitoring of the upper troposphere/lower stratosphere (UT/LS) along these routes. Data collected during the aircraft’s departure from and return to Frankfurt provide a 4 year time series of near-monthly measurements of the composition of the UT/LS above Europe. Here we present a discussion of the composition of short-lived trace gases in the whole air samples collected above Europe during CARIBIC flights. Over 150 air samples were collected between May 2005 and July 2009, or about 4 samples per month. Of the whole air samples collected, about 45% showed influence by stratospheric air (i.e. very low values of GHG, NMHC and halocarbons, elevated O3, high potential vorticity). The remaining samples were representative of the upper troposphere; back trajectories for these samples indicate that a little over half were collected in air masses that had been in the boundary layer within the previous 8 days. The predominant source regions for these samples were the Gulf of Mexico and continental North America. Owing to their wide range of chemical lifetimes and the varying composition of emissions, short-lived trace gases transported to the UT/LS can be useful indicators of source

  20. The possibility to measure the magnetic moments of short-lived particles (charm and beauty baryons) at LHC and FCC energies using the phenomenon of spin rotation in crystals

    NASA Astrophysics Data System (ADS)

    Baryshevsky, V. G.

    2016-06-01

    The use of spin rotation effect in bent crystals for measuring the magnetic moment of short-lived particles in the range of LHC and FCC energies is considered. It is shown that the estimated number of produced baryons that are captured into a bent crystal grows as ∼γ 3 / 2 with increasing particle energy. Hence it may be concluded that the experimental measurement of magnetic moments of short-lived particles using the spin rotation effect is feasible at LHC and higher energies (for LHC energies, e.g., the running time required for measuring the magnetic moment of Λc+ is 2 ÷ 16 hours).

  1. What does the oxygen isotope composition of rodent teeth record?

    NASA Astrophysics Data System (ADS)

    Royer, Aurélien; Lécuyer, Christophe; Montuire, Sophie; Amiot, Romain; Legendre, Serge; Cuenca-Bescós, Gloria; Jeannet, Marcel; Martineau, François

    2013-01-01

    Oxygen isotope compositions of tooth phosphate (δ18Op) were measured in 107 samples defined on the basis of teeth obtained from 375 specimens of extant rodents. These rodents were sampled from pellets collected in Europe from 38°N (Portugal) to 65°N (Finland) with most samples coming from sites located in France and Spain. Large oxygen isotopic variability in δ18Op is observed both at the intra- and inter-species scale within pellets from a given location. This isotopic variability is partly explained by heterochrony in tooth formation related to the short time of mineralization for all rodent species as well as the duration of mineralization that is species-dependent. Consequently, tooth phosphate of rodents records a short seasonal interval in the oxygen isotope compositions of meteoric waters (δ18Omw). In addition, inter-species isotopic variability observed in the same pellets suggests behavioural differences implying distinct isotopic compositions for species living in the same location. At the scale of Europe, a robust linear oxygen isotope fractionation equation was determined for Muroidea between the midrange δ18Op values and δ18Omw values: δ18Op=1.21(±0.20)δ18Omw+24.76(±2.70) with R2=0.79 (n=9; p<0.0001).

  2. Beyond reminders: a conceptual framework for using short message service to promote prevention and improve healthcare quality and clinical outcomes for people living with HIV.

    PubMed

    Coomes, Curtis M; Lewis, Megan A; Uhrig, Jennifer D; Furberg, Robert D; Harris, Jennie L; Bann, Carla M

    2012-01-01

    The availability of effective antiretroviral therapy has altered HIV from being an acute disease to being a chronic, manageable condition for many people living with HIV (PLWH). Because of their ubiquity and flexibility, mobile phones with short message service (SMS) offer a unique opportunity to enhance treatment and prevention for people managing HIV. To date, very few US studies using SMS for HIV self-management have been published. In this article, we review the published SMS-based intervention research that aimed to improve healthcare quality and outcomes for PLWH and other chronic health conditions, and propose a conceptual model that integrates the communication functionality of SMS with important psychosocial factors that could mediate the impact of SMS on health outcomes. We posit that an SMS-based intervention that incorporates the elements of interactivity, frequency, timing, and tailoring of messages could be implemented to encourage greater medication adherence as well as impact other mutually reinforcing behaviors and factors (e.g., increasing patient involvement and social support, reducing risk behaviors, and promoting general health and well-being) to support better healthcare quality and clinical outcomes for PLWH. We recommend that future studies explore the potential linkages between variations in SMS characteristics and these mediating factors to determine if and how they influence the larger outcomes. PMID:21933036

  3. Kinetics and Mechanism of the Chlorite-Periodate System: Formation of a Short-Lived Key Intermediate OClOIO3 and Its Subsequent Reactions.

    PubMed

    Baranyi, Nóra; Csekő, György; Valkai, László; Xu, Li; Horváth, Attila K

    2016-03-01

    The chlorite-periodate reaction has been studied spectrophotometrically in acidic medium at 25.0 ± 0.1 °C, monitoring the absorbance at 400 nm in acetate/acetic acid buffer at constant ionic strength (I = 0.5 M). We have shown that periodate was exclusively reduced to iodate, but chlorite ion was oxidized to chlorate and chlorine dioxide via branching pathways. The stoichiometry of the reaction can be described as a linear combination of two limiting stoichiometries under our experimental conditions. Detailed initial rate studies have clearly revealed that the formal kinetic orders of hydrogen ion, chlorite ion, and periodate ion are all strictly one, establishing an empirical rate law to be d[ClO2]/dt = kobs[ClO2(-)][IO4(-)][H(+)], where the apparent rate coefficient (kobs) was found to be 70 ± 13 M(-2) s(-1). On the basis of the experiments, a simple four-step kinetic model with three fitted kinetic parameters is proposed by nonlinear parameter estimation. The reaction was found to proceed via a parallel oxygen transfer reaction leading to the exclusive formation of chlorate and iodate as well as via the formation of a short-lived key intermediate OClOIO3 followed by its further transformations by a sequence of branching pathways. PMID:26849795

  4. Kinetics and Mechanism of the Chlorite-Periodate System: Formation of a Short-Lived Key Intermediate OClOIO3 and Its Subsequent Reactions.

    PubMed

    Baranyi, Nóra; Csekő, György; Valkai, László; Xu, Li; Horváth, Attila K

    2016-03-01

    The chlorite-periodate reaction has been studied spectrophotometrically in acidic medium at 25.0 ± 0.1 °C, monitoring the absorbance at 400 nm in acetate/acetic acid buffer at constant ionic strength (I = 0.5 M). We have shown that periodate was exclusively reduced to iodate, but chlorite ion was oxidized to chlorate and chlorine dioxide via branching pathways. The stoichiometry of the reaction can be described as a linear combination of two limiting stoichiometries under our experimental conditions. Detailed initial rate studies have clearly revealed that the formal kinetic orders of hydrogen ion, chlorite ion, and periodate ion are all strictly one, establishing an empirical rate law to be d[ClO2]/dt = kobs[ClO2(-)][IO4(-)][H(+)], where the apparent rate coefficient (kobs) was found to be 70 ± 13 M(-2) s(-1). On the basis of the experiments, a simple four-step kinetic model with three fitted kinetic parameters is proposed by nonlinear parameter estimation. The reaction was found to proceed via a parallel oxygen transfer reaction leading to the exclusive formation of chlorate and iodate as well as via the formation of a short-lived key intermediate OClOIO3 followed by its further transformations by a sequence of branching pathways.

  5. Quantification of regional ventilation in humans using a short-lived radiotracer--theoretical evaluation of the steady-state model

    SciTech Connect

    Valind, S.O.; Rhodes, C.G.; Jonson, B.

    1987-07-01

    The accuracy of the steady-state measurement of ventilation by means of a short-lived insoluble inert gas tracer rests with the validity of the steady-state flow equation. This has previously been applied to the qualitative assessment of regional ventilation using krypton-81m, but may potentially be used for the calculation of regional alveolar ventilation per unit alveolar gas volume--(VA/VA)cal--from measurements of the alveolar concentration of the tracer. The steady-state alveolar tracer concentration was calculated for the course of a breathing cycle, using a lung model featuring airways dead space and tidal gas flow. The calculations were made by computer simulations of a lung, characterized by predefined values of parameters describing the lung structure and the mode of ventilation. In the normal lung of supine man at rest (specific alveolar ventilation, ranging from 1.0 to 3.5 min-1) the errors of (VA/VA)cal relative to the predefined true values range from an overestimation by some 3% in the low ventilation regions to an underestimation by 8% in the best ventilated regions. The errors mainly result from ventilation of the airways dead space, which will influence the distribution of tracer in the lung by the transfer of tracer between regions by way of the common dead space and by the decay of tracer during its transport through the bronchial tree.

  6. Reaction dynamics. Extremely short-lived reaction resonances in Cl + HD (v = 1) → DCl + H due to chemical bond softening.

    PubMed

    Yang, Tiangang; Chen, Jun; Huang, Long; Wang, Tao; Xiao, Chunlei; Sun, Zhigang; Dai, Dongxu; Yang, Xueming; Zhang, Dong H

    2015-01-01

    The Cl + H2 reaction is an important benchmark system in the study of chemical reaction dynamics that has always appeared to proceed via a direct abstraction mechanism, with no clear signature of reaction resonances. Here we report a high-resolution crossed-molecular beam study on the Cl + HD (v = 1, j = 0) → DCl + H reaction (where v is the vibrational quantum number and j is the rotational quantum number). Very few forward scattered products were observed. However, two distinctive peaks at collision energies of 2.4 and 4.3 kilocalories per mole for the DCl (v' = 1) product were detected in the backward scattering direction. Detailed quantum dynamics calculations on a highly accurate potential energy surface suggested that these features originate from two very short-lived dynamical resonances trapped in the peculiar H-DCl (v' = 2) vibrational adiabatic potential wells that result from chemical bond softening. We anticipate that dynamical resonances trapped in such wells exist in many reactions involving vibrationally excited molecules.

  7. Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-lived Radioisotopes with a Shock Wave. IV. Effects of Rotational Axis Orientation

    NASA Astrophysics Data System (ADS)

    Boss, Alan P.; Keiser, Sandra A.

    2015-08-01

    Both astronomical observations of the interaction of Type II supernova remnants (SNRs) with dense interstellar clouds as well as cosmochemical studies of the abundances of daughter products of short-lived radioisotopes (SLRIs) formed by supernova nucleosynthesis support the hypothesis that the Solar System's SLRIs may have been derived from a supernova. This paper continues a series devoted to examining whether or not such a shock wave could have triggered the dynamical collapse of a dense, presolar cloud core and simultaneously injected sufficient abundances of SLRIs to explain the cosmochemical evidence. Here, we examine the effects of shock waves striking clouds whose spin axes are oriented perpendicular, rather than parallel, to the direction of propagation of the shock front. The models start with 2.2 {M}⊙ cloud cores and shock speeds of 20 or 40 km s-1. Central protostars and protoplanetary disks form in all models, although with their disk spin axes aligned somewhat randomly. The disks derive most of their angular momentum not from the initial cloud rotation, but from the Rayleigh-Taylor fingers that also inject shock wave SLRIs. Injection efficiencies, fi, the fraction of the incident shock wave material injected into the collapsing cloud core, are ˜0.04-0.1 in these models, similar to when the rotation axis is parallel to the shock propagation direction. Evidently, altering the rotation axis orientation has only a minor effect on the outcome, strengthening the case for this scenario as an explanation for the Solar System's SLRIs.

  8. Long-Lived CD4+IFN-γ+ T Cells rather than Short-Lived CD4+IFN-γ+IL-10+ T Cells Initiate Rapid IL-10 Production To Suppress Anamnestic T Cell Responses during Secondary Malaria Infection

    PubMed Central

    Villegas-Mendez, Ana; Inkson, Colette A.; Shaw, Tovah N.; Strangward, Patrick

    2016-01-01

    CD4+ T cells that produce IFN-γ are the source of host-protective IL-10 during primary infection with a number of different pathogens, including Plasmodium spp. The fate of these CD4+IFN-γ+IL-10+ T cells following clearance of primary infection and their subsequent influence on the course of repeated infections is, however, presently unknown. In this study, utilizing IFN-γ–yellow fluorescent protein (YFP) and IL-10–GFP dual reporter mice, we show that primary malaria infection–induced CD4+YFP+GFP+ T cells have limited memory potential, do not stably express IL-10, and are disproportionately lost from the Ag-experienced CD4+ T cell memory population during the maintenance phase postinfection. CD4+YFP+GFP+ T cells generally exhibited a short-lived effector rather than effector memory T cell phenotype postinfection and expressed high levels of PD-1, Lag-3, and TIGIT, indicative of cellular exhaustion. Consistently, the surviving CD4+YFP+GFP+ T cell–derived cells were unresponsive and failed to proliferate during the early phase of secondary infection. In contrast, CD4+YFP+GFP− T cell–derived cells expanded rapidly and upregulated IL-10 expression during secondary infection. Correspondingly, CD4+ T cells were the major producers within an accelerated and amplified IL-10 response during the early stage of secondary malaria infection. Notably, IL-10 exerted quantitatively stronger regulatory effects on innate and CD4+ T cell responses during primary and secondary infections, respectively. The results in this study significantly improve our understanding of the durability of IL-10–producing CD4+ T cells postinfection and provide information on how IL-10 may contribute to optimized parasite control and prevention of immune-mediated pathology during repeated malaria infections. PMID:27630165

  9. Constraining the Time-Scale of Interaction of Sea Ice Sediments and Surface Sea Water in the Arctic Ocean Using Short-Lived Radionuclide Tracers

    NASA Astrophysics Data System (ADS)

    Baskaran, M.; Andersson, P. S.; Jweda, J.; Dahlqvist, R.; Ketterer, M. E.

    2007-12-01

    We measured the activities of short-lived radionuclides (Th-234, Be-7, Po-210, Pb-210, Cs-137, Th-234, Ra-226 and Ra-228) and concentrations of several elements (Be, Pb, Fe, Al, Co, Ni, Cu and Zn) on a suite of ice-rafted sediments (IRS) collected during BERINGIA-2005 in the Western Arctic Ocean. A suite of water samples were also collected and analyzed for particulate and dissolved Be-7, Po-210, Pb-210, Th-234, Ra-226 and Ra-228. The activities of Be-7 and Pb-210 in the IRS are 1-2 orders of magnitude higher than those reported in the source sediments. Presence of excess Th-234 in the IRS indicates that the removal of Th-234 from surface seawater took place on time scales comparable to the mean-life of Th-234. While the Po-210/Pb-210 activity ratios in the source sediments (1.0) and the atmospheric depositional input (~0.1) are known, varying ratios of 0.78 to 1.0 were found in the IRS. This ratio can be utilized to obtain the residence time of the IRS in sea ice. The activity of Ra-226 and Ra-228 in all the IRS is nearly constant (within a factor of 1.6) and are comparable to the benthic sediments in the source region. The activities of atmospherically-delivered radionuclides, Be-7 and Pb-210, in IRS varied by factors of ~4.5 and 9, respectively, and this variation is attributed to differences in the extent of interaction of surface water with IRS and differences in the mean-lives of these nuclides. While significant enrichment of Be-7 and Pb-210 has been found, there is no enrichment of stable Pb or Be. The Al-normalized enrichment factor for elements measured (Co, Ni, Cu, Zn, Pb and Be) indicate that there is no significant enrichment of these elements, with Al-normalized enrichment factors less than 1.3.

  10. Age and isotopic relationships among the angrites Lewis Cliff 86010 and Angra dos Reis

    SciTech Connect

    Lugmair, G.W. ); Galer, S.J.G. Max-Planck-Inst. fuer Chemie, Mainz )

    1992-04-01

    Results of a wide-ranging isotopic investigation of the unique Antarctican angrite LEW-86010 (LEW) are presented, together with a reassessment of the type angrite Angra dos Reis (ADOR). The principal objectives of this study are to obtain precise radiometric ages, initial Sr isotopic compositions, and to search for the erstwhile presence of the short-lived nuclei {sup 146}Sm and {sup 26}Al via their daughter products. The isotopic compositions of Sm, U, Ca, and Ti were also measured. This allows a detailed appraisal to be made of the relations between, and the genealogy of, these two angrites.

  11. Mass measurements on radioactive isotopes with a Penning trap mass spectrometer

    SciTech Connect

    Bollen, G.; Ames, F.; Schark, E.; Audi, G.; Lunney, D.; Saint Simon, M. de; Beck, D.; Herfurth, F.; Kluge, H.-J.; Kohl, A.; Schwarz, S.; Moore, R. B.; Szerypo, J.

    1999-01-15

    Penning trap mass measurements on short-lived isotopes are performed with the ISOLTRAP mass spectrometer at the radioactive beam facility ISOLDE/CERN. In the last years the applicability of the spectrometer has been considerably extended by the installation of an RFQ trap ion beam buncher and a new cooler Penning trap, which is operated as an isobar separator. These improvements allowed for the first time measurements on isotopes of rare earth elements and on isotopes with Z=80-85. In all cases an accuracy of {delta}m/m{approx_equal}1{center_dot}10{sup -7} was achieved.

  12. Development of fast-release solid catchers for rare isotopes

    NASA Astrophysics Data System (ADS)

    Nolen, Jerry; Greene, John; Elam, Jeffrey; Mane, Anil; Sampathkumaran, Uma; Winter, Raymond; Hess, David; Mushfiq, Mohammad; Stracener, Daniel; Wiendenhoever, Ingo

    2015-04-01

    Porous solid catchers of rare isotopes are being developed for use at high power heavy ion accelerator facilities such as RIKEN, FRIB, and RISP. Compact solid catchers are complementary to helium gas catchers for parasitic harvesting of rare isotopes in the in-flight separators. They are useful for short lived isotopes for basic nuclear physics research and longer-lived isotopes for off-line applications. Solid catchers can operate effectively with high intensity secondary beams, e.g. >> 1E10 atoms/s with release times as short as 10-100 milliseconds. A new method using a very sensitive and efficient RGA has been commissioned off-line at Argonne and is currently being shipped to Florida State University for in-beam measurements of the release curves using stable beams. The same porous solid catcher technology is also being evaluated for use in targets for the production of medical isotopes such as 211-At. Research supported by the U.S. DOE Office of Nuclear Physics under the SBIR Program and Contract # DE-AC02-06CH11357 and a University of Chicago Comprehensive Cancer Center/ANL Pilot Project.

  13. Dating the Laschamp Excursion: Why Speleothems are Valuable Tools for Constraining the Timing and Duration of Short-Lived Geomagnetic Events

    NASA Astrophysics Data System (ADS)

    Lascu, I.; Feinberg, J. M.; Dorale, J. A.; Cheng, H.; Edwards, R. L.

    2015-12-01

    Short-lived geomagnetic events are reflections of geodynamo behavior at small length scales. A rigorous documentation of the anatomy, timing, duration, and frequency of centennial-to-millennial scale geomagnetic events can be invaluable for theoretical and numerical geodynamo models, and for the understanding the finer dynamics of the Earth's core. A critical ingredient for characterizing such geomagnetic instabilities are tightly constrained age models that enable high-resolution magnetostratigraphies. Here we focus on a North American speleothem geomagnetic record of the Laschamp excursion, which was the first geomagnetic excursion recognized and described in the paleomagnetic record, and remains the most studied event of its kind. The geological significance of the Laschamp lies chiefly in the fact that it constitutes a global time-synchronous geochronological marker. The Laschamp excursion occurred around the time of the demise of Homo neanderthalensis, in conjunction with high-amplitude, rapid climatic oscillations leading into the Last Glacial Maximum, and precedes a major supervolcano eruption in the Mediterranean. Thus, the precise determination of the timing and duration of the Laschamp would help in elucidating major scientific questions situated at the intersection of geology, paleoclimatology, and anthropology. Here we present a geomagnetic record from a stalagmite collected in Crevice Cave, Missouri, which we have dated using a combination of high-precision 230Th ages and annual layer counting using confocal microscopy. We have found a maximum duration for the Laschamp that spans the interval 42,250-39,700 years BP, and an age of 41,100 ± 350 years BP for the height of the excursion. During this period relative paleointensity decreased by an order of magnitude and the virtual geomagnetic pole was located at southerly latitudes. Our chronology provides the first robust bracketing for the Laschamp excursion, and improves on previous age determinations

  14. TRIGGERING COLLAPSE OF THE PRESOLAR DENSE CLOUD CORE AND INJECTING SHORT-LIVED RADIOISOTOPES WITH A SHOCK WAVE. I. VARIED SHOCK SPEEDS

    SciTech Connect

    Boss, Alan P.; Keiser, Sandra A.; Ipatov, Sergei I.; Myhill, Elizabeth A.; Vanhala, Harri A. T. E-mail: keiser@dtm.ciw.ed E-mail: elizabeth.myhill@marymount.ed

    2010-01-10

    The discovery of decay products of a short-lived radioisotope (SLRI) in the Allende meteorite led to the hypothesis that a supernova shock wave transported freshly synthesized SLRI to the presolar dense cloud core, triggered its self-gravitational collapse, and injected the SLRI into the core. Previous multidimensional numerical calculations of the shock-cloud collision process showed that this hypothesis is plausible when the shock wave and dense cloud core are assumed to remain isothermal at approx10 K, but not when compressional heating to approx1000 K is assumed. Our two-dimensional models with the FLASH2.5 adaptive mesh refinement hydrodynamics code have shown that a 20 km s{sup -1} shock front can simultaneously trigger collapse of a 1 M{sub sun} core and inject shock wave material, provided that cooling by molecular species such as H{sub 2}O, CO, and H{sub 2} is included. Here, we present the results for similar calculations with shock speeds ranging from 1 km s{sup -1} to 100 km s{sup -1}. We find that shock speeds in the range from 5 km s{sup -1} to 70 km s{sup -1} are able to trigger the collapse of a 2.2 M{sub sun} cloud while simultaneously injecting shock wave material: lower speed shocks do not achieve injection, while higher speed shocks do not trigger sustained collapse. The calculations continue to support the shock-wave trigger hypothesis for the formation of the solar system, though the injection efficiencies in the present models are lower than desired.

  15. RNA-seq of the aging brain in the short-lived fish N. furzeri – conserved pathways and novel genes associated with neurogenesis

    PubMed Central

    Baumgart, Mario; Groth, Marco; Priebe, Steffen; Savino, Aurora; Testa, Giovanna; Dix, Andreas; Ripa, Roberto; Spallotta, Francesco; Gaetano, Carlo; Ori, Michela; Terzibasi Tozzini, Eva; Guthke, Reinhard; Platzer, Matthias; Cellerino, Alessandro

    2014-01-01

    The brains of teleost fish show extensive adult neurogenesis and neuronal regeneration. The patterns of gene regulation during fish brain aging are unknown. The short-lived teleost fish Nothobranchius furzeri shows markers of brain aging including reduced learning performances, gliosis, and reduced adult neurogenesis. We used RNA-seq to quantify genome-wide transcript regulation and sampled five different time points to characterize whole-genome transcript regulation during brain aging of N. furzeri. Comparison with human datasets revealed conserved up-regulation of ribosome, lysosome, and complement activation and conserved down-regulation of synapse, mitochondrion, proteasome, and spliceosome. Down-regulated genes differ in their temporal profiles: neurogenesis and extracellular matrix genes showed rapid decay, synaptic and axonal genes a progressive decay. A substantial proportion of differentially expressed genes (∼40%) showed inversion of their temporal profiles in the last time point: spliceosome and proteasome showed initial down-regulation and stress-response genes initial up-regulation. Extensive regulation was detected for chromatin remodelers of the DNMT and CBX families as well as members of the polycomb complex and was mirrored by an up-regulation of the H3K27me3 epigenetic mark. Network analysis showed extensive coregulation of cell cycle/DNA synthesis genes with the uncharacterized zinc-finger protein ZNF367 as central hub. In situ hybridization showed that ZNF367 is expressed in neuronal stem cell niches of both embryonic zebrafish and adult N. furzeri. Other genes down-regulated with age, not previously associated with adult neurogenesis and with similar patterns of expression are AGR2, DNMT3A, KRCP, MEX3A, SCML4, and CBX1. CBX7, on the other hand, was up-regulated with age. PMID:25059688

  16. Stepwise Catalytic Mechanism via Short-Lived Intermediate Inferred from Combined QM/MM MERP and PES Calculations on Retaining Glycosyltransferase ppGalNAcT2

    PubMed Central

    Trnka, Tomáš; Kozmon, Stanislav; Tvaroška, Igor; Koča, Jaroslav

    2015-01-01

    The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi). The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals. PMID:25849117

  17. Stepwise catalytic mechanism via short-lived intermediate inferred from combined QM/MM MERP and PES calculations on retaining glycosyltransferase ppGalNAcT2.

    PubMed

    Trnka, Tomáš; Kozmon, Stanislav; Tvaroška, Igor; Koča, Jaroslav

    2015-04-01

    The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi). The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals.

  18. The Multi-Temporal Database of Planetary Image Data (MUTED): A database to support the identification of surface changes and short-lived surface processes

    NASA Astrophysics Data System (ADS)

    Erkeling, G.; Luesebrink, D.; Hiesinger, H.; Reiss, D.; Heyer, T.; Jaumann, R.

    2016-06-01

    Images of Mars taken by spacecraft in the last few decades indicate that the landscape has changed and that current processes are continuously changing the surface. The modifications of the landscape are caused by exogenic processes including eolian activity, mass movement, the growth and retreat of the polar caps, glacial processes and crater-forming impacts. In particular the High Resolution Stereo Camera (HRSC) on board Mars Express (MEx) and the Context Camera (CTX) on board the Mars Reconnaissance Orbiter (MRO) cover large areas at high resolution and thus are particularly well-suited to detect the extent and origin of surface changes on Mars. Multi-temporal observations of variable features on Mars became possible by the increasing number of repeated image acquisitions of the same surface areas. To support the investigation of surface changes that represents a key element in martian research, we developed MUTED, the "Multi-Temporal Database of Planetary Image Data", which is a tool for the identification of the spatial and multi-temporal coverage of planetary image data from Mars. Using MUTED, scientists are able to identify the location, number, and time range of acquisitions of overlapping images from, for example, HRSC and CTX. MUTED also includes images from other planetary datasets such as those of the Mars Orbiter Camera (MOC), the Thermal Emission Imaging System (THEMIS), and the High Resolution Imaging Science Experiment (HiRISE). The database supports the identification and analysis of surface changes and short-lived surface processes on Mars based on fast automatic planetary image database queries. From the multi-temporal planetary image database and investigations based on multi-temporal observations we will better understand the interactions between the surface of Mars and external forces, including the atmosphere. MUTED is available for the planetary scientific community via the webpage of the Institut für Planetologie (IfP) Muenster.

  19. Time-series variations of the short-lived Ra in coastal waters: implying input of SGD to the coastal zone of Da-Chia River, Taichung, Taiwan

    NASA Astrophysics Data System (ADS)

    Hsu, Feng-Hsin; Su, Chih-Chieh; Lin, In-Tain; Huh, Chih-An

    2015-04-01

    Submarine groundwater discharge (SGD) has been recognized as an important pathway for materials exchanging between land and sea. Input of SGD carries the associated nutrients, trace metals, and inorganic carbon that may makes great impacts on ecosystem in the coastal zone. Due to the variability of SGD magnitude, it is difficult to estimate the flux of those associated materials around the world. Even in the same area, SGD magnitude also varies in response to tide fluctuation and seasonal change on hydraulic gradient. Thus, long-term investigation is in need. In Taiwan, the SGD study is rare and the intrusion of seawater in the coastal aquifer is emphasized in previous studies. According to the information from Hydrogeological Data Bank (Central Geological Survey, MOEA), some areas still show potentiality of SGD. Here, we report the preliminary investigation result of SGD at Gaomei Wildlife Conservation Area which located at the south of the Da-Chia River mouth. This study area is characterized by a great tidal rang and a shallow aquifer with high groundwater recharge rate. Time-series measurement of the short-lived Ra in surface water was done in both dry and wet seasons at a tidal flat site and shows different trends of excess Ra-224 between dry and wet seasons. High excess Ra-224 activities (>20 dpm/100L) occurred at high tide in dry season but at low tide in wet season. The plot of salinity versus excess Ra-224, showing non-conservative curve, suggests that high excess Ra-224 activities derive from desorption in dry season but from SGD input in wet season.

  20. The prolactin response to an acute stressor in relation to parental care and corticosterone in a short-lived bird, the Eurasian hoopoe.

    PubMed

    Schmid, Baptiste; Chastel, Olivier; Jenni, Lukas

    2011-10-01

    Prolactin plays an important role in mediating parental care in birds, but little is known about changes in prolactin levels when animals disrupt their reproductive behaviour during emergency life-history stages. We investigated the variation of prolactin levels with breeding stage, sex, body condition and as a response to a standardized acute stressor in a small short-lived bird, the Eurasian hoopoe Upupa epops under natural field conditions. We found higher baseline levels of prolactin in females during the brooding phase than in their mates which feed them and their chicks at this stage. Moreover, this is the first report of a differential prolactin stress-response between sexes with contrasting parental care within a breeding phase. Capture, handling and restraint induced a clear decrease of prolactin levels which was less pronounced in females at the very early stage of brooding compared to females in later stages. In contrast, the prolactin stress response in males remained nearly constant over the breeding stages and was stronger than in females. Baseline levels of prolactin, but not handling-induced levels, were positively correlated with body condition. We found a weak relationship between the decrease in prolactin due to acute handling stress and handling-induced levels of corticosterone. Taken together, both baseline and stress response levels of prolactin were related to the amount of parental care, although we found no relationship with reproductive success. It appears that the response to an acute stressor in prolactin levels is finely tuned to parental duties and investment. Hence, prolactin appears to be involved in mediating the trade-off between current reproduction versus self-maintenance and future reproduction.

  1. Brick Kiln Emissions Quantified with the Aerodyne Mobile Laboratory During the Short Lived Climate Forcing (SLCF) 2013 Campaign in Guanajuato Mexico

    NASA Astrophysics Data System (ADS)

    Fortner, E.; Knighton, W. B.; Herndon, S.; Roscioli, J. R.; Zavala, M.; Onasch, T. B.; Jayne, J. T.; Worsnop, D. R.; Kolb, C. E.; Molina, L. T.

    2013-12-01

    Brick kiln emissions are suspected to be a major source of atmospheric black carbon (BC) in developing countries; and black carbon's role as a short lived climate forcing (SLCF) pollutant is widely recognized. The SLCF-Mexico brick kiln study was conducted from 12-17 March 2013 in Mexico's Guanajuato state. Three different types of brick kilns were investigated (MK2, traditional, and traditional three tier) providing data on the effects of different kiln designs on particle and gas phase emissions. The BC and gaseous combustion emissions from these kilns were measured during both the fire stage and the subsequent smoldering stage with real-time instruments deployed on the Aerodyne Mobile Laboratory, and quantified utilizing flux tracer gases released adjacent to the brick kiln. This method allows examination of the brick kiln plume's evolution as it transits downwind from the source. Particulate measurements conducted by the mobile laboratory included the multi angle absorption photometer (MAAP) to measure black carbon mass, cavity attenuated phase shift (CAPSext) monitor to measure extinction and soot particle aerosol mass spectrometer (SP-AMS) measurements of black carbon. The SP-AMS instrument combines the ability to measure black carbon with the ability to determine the chemical composition of the other particulate matter (PM) components associated with black carbon particles. The variance of PM chemical composition will be examined as a function of burning stage and kiln type and compared to other black carbon PM sources. Gas phase exhaust species measured included CO, CO2, NOx, SO2, CH4, C2H6, as well as a variety of VOCs (acetonitrile, benzene etc.) measured with a PTR-MS instrument. All of these measurements will be examined to construct emission ratios evaluating how these vary with different kiln types and different firing conditions. The evolution of particulate matter and gas phase species as they transit away from the source will also be examined.

  2. Synthesis of Trace Gas and Aerosol Observations and Evaluation of Modelled Short-lived Climate Pollutants Across the Pan-Eurasian High Latitudes

    NASA Astrophysics Data System (ADS)

    Arnold, S.; Nieminen, T.

    2015-12-01

    Model calculations suggest that changes in short-lived climate pollutants (SLCPs) such as ozone and aerosol may have contributed significantly to rapid Arctic warming over the past century. Arctic tropospheric budgets of SLCPs are impacted by long-range transport of trace gases and aerosols from Europe, Asia and N. America, but also by local sources such as gas flaring, shipping and boreal fires. Recently, the POLARCAT Model Intercomparison Project (POLMIP) showed that significant model biases persist through the depth of the European and North American high latitude troposphere in modelled trace-gas abundances. Evaluation of models over the Siberian high latitudes is challenging due to a severe paucity of available observations, despite the potential importance of this region as a route for European pollution export to the Arctic. Despite the existence of a number of limited datasets, which could be used for model evaluation in this region, until now no effort has been made to synthesise and exploit these observations to evaluate modelled abundances of SLCPs such as tropospheric ozone & aerosol. In this presentation, we will show evaluation of simulated aerosol, tropospheric ozone, and precursor species in several global chemical transport models, using a synthesis of available surface, aircraft and satellite observations over the high latitude pan-Eurasian region. We use models and observations to investigate source regions contributing to remote Siberian SLCP abundances over the annual cycle, and show substantial biases in simulated aerosol and trace gas concentrations that are consistent across a suite of different models. These comparisons constitute the first multi-model evaluation of tropospheric composition in the pan-Eurasin region using observations from across the broad region. Finally, we use the model simulations to determine optimum locations for the development of future monitoring activities in high latitude Eurasia with an aim of better

  3. 2014 ICHLNRRA intercomparison of radon/thoron gas and radon short-lived decay products measuring instruments in the NRPI Prague.

    PubMed

    Jílek, K; Timková, J

    2015-06-01

    During the Eighth International Conference on High Levels of Natural Radiation and Radon Areas held in autumn 2014 at Prague, the third intercomparison of radon/thoron gas and radon short-lived decay products measurement instruments was organised by and held at the Natural Radiation Division of the National Radiation Protection Institute (NRPI; SÚRO v.v.i.) in Prague. The intercomparison was newly focussed also on continuous monitors with active sampling adapters capable to distinguish radon/thoron gas in their mix field.The results of radon gas measurements carried out in the big NRPI radon chamber indicated very well an average deviation of up to 5 % from the reference NRPI value for 80 % of all the exposed instruments. The results of equilibrium equivalent concentration continuous monitors indicated an average deviation of up to 5 % from the reference NRPI value for 40 % of all the exposed instruments and their ~8-10 % shift compared with the NRPI. The results of investigated ambient conditions upon response of exposed continuous monitors indicated influence of aerosol changes upon response of radon monitors with an active air sampling adapters through the filter, only. The exposures of both radon/thoron gas discriminative continuous monitors and passive detectors have been indicated inconsistent results: on one hand, their excellent agreement up to several per cent for both the gases, and on the other hand, systematic unsatisfactory differences up to 40 %. Additional radon/thoron exercises are recommended to improve both the instruments themselves and quality of their operators.

  4. Higher central fat and poor self-body image in short-stature overweight/obese women living in Brazilian shantytowns

    PubMed Central

    Florêncio, Telma Toledo; Cavalcante, Fabiana Albuquerque; Lins, Isabela Lopes; Clemente, Ana Grotti; Sawaya, Ana Lydia

    2016-01-01

    Background Short stature in adult life, a possible consequence of poor perinatal conditions, is associated with higher risk of mortality and social disabilities. We aimed to determine whether low-income, overweight/obese, short-stature (SS) women show alterations in body composition, self-body-image perception, and biochemical profile compared to their non-short (NS) counterparts. Methods A cross-sectional study was conducted with women living in shantytowns and mother or relatives to undernourished children treated in a center for recuperation and nutritional education. Inclusion criteria were: (1) age, 19–45 years; (2) stature < 152.3 cm or > 158.7 cm; and (3) body mass index > 25 kg/m2. Socioeconomic, anthropometric, biochemical, and body image data were collected. We analyzed 56 SS and 57 NS women. Results The SS group showed a higher waist-to-height ratio (WHtR) (mean: 0.63; standard deviation: 0.06 for SS and mean: 0.60; standard deviation: 0.07 for the NS group; p = 0.02), and, in the adjusted analysis, showed lower fat-free mass (Estimated Marginal Mean for the SS group: 45.7 kg 95% confidence intervals (CI) (45.2–46.2) and for the NS group: 46.9 kg 95% CI (46.4–47.4); p < 0.01) and higher fat mass (Estimated Marginal Mean for the SS group: 32.5 95% CI (31.9–33.0) and for the NS group: 31.4 kg 95% CI (30.9–31.9); p < 0.01). Body mass index was a better predictor of current self-body-image perception for NS women. The SS coefficient values were β = 0.141, SE = 0.059, and R2-Nagelkerke = 0.107, and the NS coefficients values were β = 0.307, SE = 0.058, and R2-Nagelkerke = 0.491 (Z = 2.006; p < 0.05). Considering the obese subgroup, six out of 32 (18.8%) SS women and 14 out of 33 (42.4%) NS women perceived themselves as obese (χ2 = 4.27; p = 0.03). This difference remained significant even after adjustment by age, schooling, and number of children (p = 0.04). Only the total thyroxin showed significant differences between groups, lower in SS women

  5. Submarine groundwater discharge estimation in an urbanized embayment in Hong Kong via short-lived radium isotopes and its implication of nutrient loadings and primary production.

    PubMed

    Luo, Xin; Jiao, Jiu Jimmy; Moore, W S; Lee, Chun Ming

    2014-05-15

    (224)Ra and (223)Ra are adopted as tracers to qualify submarine groundwater discharge (SGD) in Tolo Harbor, a highly urbanized embayment in Hong Kong. Based on the sampling data, a two-layered radium mass balance model is used to estimate lateral SGD and bottom SGD. Total SGD is estimated to be 1.2-3.0 cm d(-1), including lateral SGD of 5.7-7.9 cm d(-1) and bottom SGD of 0.3-2.0 cm d(-1). Fresh SGD is estimated to be (2.1-5.5) × 10(5)m(3)d(-1). Nutrient fluxes (mold(-1)) from SGD are estimated to be (3-7.4) × 10(4) (dissolved inorganic nitrogen), (2.4-6.2) × 10(2) (dissolved inorganic phosphate) and (6.5-16) × 10(4) (dissolved silicate). Primary productivity is estimated to be (1.5-15) × 10(6)gCd(-1), 2-53% of which is supported by SGD-induced phosphate fluxes. The study indicates that SGD is a significant source of nutrients to coastal waters and may cause an obvious increase of primary production. These findings must be considered in future coastal ecological management.

  6. Timescales of Magmatic processes in Eastern Sunda Arc: Rindjani and Tambora in light of new geochemical data including short lived U-Th series isotopes

    NASA Astrophysics Data System (ADS)

    Paraschivoiu, Viorel

    2010-05-01

    Tambora and Rindjani are active volcanoes situated on the neighbouring islands of Lombok and Sumbawa in the Eastern Sunda Arc. Both are stratovolcanoes situated about 300 km north of the Java Trench and between 170 and 200 km above the Benioff seismic zone (Hamilton, 1974; Hutchinson, 1976). Rindjani's lavas are calc-alkaline ankaramites, hi-Al basalts to andesites, hi-K andesites and dacites. Tambora's lavas are ne-normative relatively potassium rich trachyandesites and trachybasalts including the intermediate (<57% SiO2) members (Foden, 1979, PhD thesis) which is the main difference to Rindjani's lavas. On a more general scale, Tambora's lavas are intermediate between the Hi-Al basalt-andesite of Rindjani and the highly undersaturated K-rich, leucite bearing lavas of G. Soromundi and G. Sangenges (both extinct volcanoes situated on Sumbawa east and respectively west of Tambora). There are other important differences however. Tambora's lavas remain ne-normative throughout the entire suite, whereas Rindjani's become Q-normative in the more evolved members (>53%SiO2). The concentrations of K2O, Rb, Sr and P2O5 are also very different between the two suites (Foden, 1979). Both volcanoes however show minor U-Th series disequilibrium with either Th or U excess but less than 10%, typical of this sector of the Eastern Sunda Arc. Investigating data across the whole arc, (Turner & Foden, 2001) have interpreted that mantle wedge has had a sediment component added as a melt and slab derived fluids added afterwards could not imprint their Th-U disequilibrium over the high Th signature of the sedimentary material. Evidence from volcanoes where the sediment component does not show as markedly (Iya, Werung) in the form of large U238/Th230 and (Ra226/Th230)0 suggests evolutionary timescales for magmatic processes of less than 8000years. Furthermore, in a 2003 paper, Turner et al., investigate the timescales of magmatic evolution of Sangeang Api, another active volcano just off the northern coast of Sumbawa and found that the residence times of magmas here are in the order of 2000 years and by analogy with the 226Ra/230Th ratio of Tambora's 1815 lava suggest a residence time of 5000 years, figure which correlates with the time lapsed since the previous major eruption at Tambora (Takada et al., 2000). New data generated shows a wider range of values for Tambora where (238U/232Th) is between .46 and .9 and (230Th/232Th) between .56 and .841 whereas for Rindjani the data is more closely grouped between .692 and .821 for (238U/232Th) and .725 to .833 for (230Th/232Th). An interesting feature of the Rindjani data is that it shows a distinct break between the precaldera samples and the freshly erupted lavas of Anak Rindjani (the newly formed cone inside the caldera) which shows clearly the younger lavas are closer to radioactive equilibrium. The possibility that these two groups represent different batches of magmas is examined and compared to Tambora's data where precaldera lavas and the 1815 pumice are consistent and seem to lie on the same line, suggesting the evolving magma chamber that has discharged in the 1815 eruption were part of the same batch.

  7. The isotope record of short- and long-term dietary changes in sheep tooth enamel: Implications for quantitative reconstruction of paleodiets

    NASA Astrophysics Data System (ADS)

    Zazzo, A.; Balasse, M.; Passey, B. H.; Moloney, A. P.; Monahan, F. J.; Schmidt, O.

    2010-06-01

    Quantitative reconstruction of paleodiet by means of sequential sampling and carbon isotope analysis in hypsodont tooth enamel requires a precise knowledge of the isotopic enrichment between dietary carbon and carbon from enamel apatite ( ɛD-E), as well as of the timing and duration of the enamel mineralization process (amelogenesis). To better constrain these parameters, we performed a series of controlled feeding experiments on sheep ranging in age from 6 to 24 months-old. Twenty-eight lambs and 14 ewes were fed isotopically distinct diets for different periods of time, and then slaughtered, allowing the timing and rate of molar growth to be determined. High resolution sampling and stable carbon isotope analysis of breath CO 2 performed on six individuals following a diet-switch showed that 70-90% of dietary carbon had turned over in less than 24 h. Sequential sampling and carbon isotopic analysis was performed on the first (M 1) and second (M 2) lower molars of four lambs as well as on the third lower molar (M 3) of 11 ewes. The changes in diet were recorded in all molars. We found that the length of enamel matrix apposition is approximately one-quarter of the final tooth length during crown extension, and that enamel maturation spans slightly less than 3 months in M 1, and 4 months in M 2 and M 3. Portions of enamel in equilibrium with dietary carbon were used to calculate ɛD-E values. Animals on grass silage diets had values similar to previous observations, whereas animal switched to pelleted corn diets had values ca. 4‰ lower, a pattern consistent with lower methane production observed for animals fed concentrate diets. The tooth enamel forward model of Passey and Cerling (2002) closely predicted the amplitude of isotope changes recorded in tooth enamel, but slightly underestimated the rate of isotope change, suggesting that the rate of accumulation of carbonate during maturation may not be constant over time. Although stable isotope profiles in tooth

  8. Formation of short-lived radionuclides in the protoplanetary disk during late-stage irradiation of a volatile-rich reservoir

    SciTech Connect

    Jacobsen, B; Matzel, J; Hutcheon, I D; Krot, A N; Yin, Q -; Nagashima, K; Ramon, E; Weber, P; Ishii, H; Ciesla, F

    2010-11-30

    The origin of short-lived (t{sub 1/2} < 5 Myr) and now extinct radionuclides ({sup 10}Be, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, {sup 53}Mn, {sup 60}Fe; hereafter SLRs) is fundamental to understanding the formation of the early solar system. Two distinct classes of models have been proposed to explain the origin of SLRs: (1) injection from a nearby stellar source (e.g., supernova, asymptotic giant branch star or Wolf-Rayet star) and (2) solar energetic particle irradiation of dust and gas near the proto-Sun. Recent studies have demonstrated that {sup 36}Cl was extant in the early solar system. However, its presence, initial abundance and the noticeable decoupling from {sup 26}Al raise serious questions about the origin of SLRs. Here we report {sup 36}Cl-{sup 36}S and {sup 26}Al-{sup 26}Mg systematics for wadalite and grossular, secondary minerals in a calcium-aluminum-rich inclusion (CAI) from the CV chondrite Allende that allow us to reassess the origin of SLRs. The inferred abundance of {sup 36}Cl in wadalite, corresponding to a {sup 36}Cl/{sup 35}Cl ratio of (1.81 {+-} 0.13) x 10{sup -5}, is the highest {sup 36}Cl abundance reported in any early solar system material. The high level of {sup 36}Cl in wadalite and the absence of {sup 26}Al ({sup 26}Al/{sup 27}Al {le} 3.9 x 10{sup -6}) in co-existing grossular indicates that (1) {sup 36}Cl formed by late-stage solar energetic particle irradiation and (2) the production of {sup 36}Cl, recorded by secondary minerals, is unrelated to the origin of {sup 26}Al and other SLRs ({sup 10}Be, {sup 53}Mn) recorded by primary minerals of CAIs and chondrules. We conclude that 36Cl was produced by solar energetic particle irradiation of a volatile-rich reservoir in an optically thin protoplanetary disk adjacent to the accretion region of the CV chondrite parent asteroid.

  9. The last stages of the Avalonian-Cadomian arc in NW Iberian Massif: isotopic and igneous record for a long-lived peri-Gondwanan magmatic arc

    NASA Astrophysics Data System (ADS)

    Andonaegui, Pilar; Arenas, Ricardo; Albert, Richard; Sánchez Martínez, Sonia; Díez Fernández, Rubén; Gerdes, Axel

    2016-06-01

    The upper allochthonous units of NW Iberian Massif contain an extensive Cambrian magmatism (c. 500 Ma), covering felsic to mafic compositions. The magmatic activity generated large massifs of granitoids and gabbros, with calc-alkaline and tholeiitic compositions respectively. Petrological and geochemical features of these massifs are characteristic of volcanic arc. The plutons intruded siliciclastic sedimentary series deposited in the periphery of the West Africa Craton. U-Pb/Hf isotopic compositions of detrital zircon in the siliciclastic host series, indicate continental arc activity between c. 750 Ma and c. 500 Ma. It was characterized by a large variety of isotopic sources, including from very old continental input, even Archean, to the addition of a significant amount of juvenile mafic material. These isotopic sources experienced an extensive mixing that explains the composition and isotopic features (εHft from - 50 until + 15) of the represented Cambrian plutons. The Cambrian igneous rocks of the upper units of NW Iberia are related to the latest activity of the Avalonian-Cadomian arc. From the Middle Cambrian arc activity in the periphery of Gondwana was replaced by pronounced extension associated with the development of continental rifting, which finally led to separation of the microcontinent Avalonia. Subsequent drifting of Avalonia to the North caused progressive opening one of the main Paleozoic ocean, the Rheic Ocean.

  10. Oxygen isotope disequilibrium between quartz and sanidine from the Bandelier Tuff, New Mexico, consistent with a short residence time of phenocrysts in rhyolitic magma

    NASA Astrophysics Data System (ADS)

    Wolff, John A.; Balsley, Steven D.; Gregory, Robert T.

    2002-07-01

    Oxygen isotope analyses are reported from co-existing quartz and feldspar from the Bandelier Tuff and Cerro Toledo high-silica rhyolitic pyroclastic deposits erupted from the Valles caldera, New Mexico. Quartz shows little variation outside analytical error, but δ 18O in feldspar varies over >1‰. In most samples, 18O/ 16O fractionation between quartz and feldspar is significantly less than is predicted for equilibrium at temperatures appropriate for rhyolitic magma. In the Tshirege (upper) Member of the Bandelier Tuff, isotopic fractionation between mineral pairs is close to equilibrium in the later erupted ignimbrite, but non-equilibrium in the initial Plinian deposit. These relationships are interpreted in terms of a model where most phenocrysts are derived from a highly porphyritic carapace around the magma chamber that was disrupted by eruption, thus scattering crystals throughout the magma. Carapace quartz and feldspar are initially isotopically lighter than the bulk aphyric magma, due to chemical communication with low-δ 18O country rock in the meteoric/hydrothermal system surrounding the chamber. We assume that quartz and feldspar were initially in isotopic equilibrium. Diffusive re-equilibration of crystals begins when the carapace disintegrates and the minerals are immersed in the bulk magma just prior to and during eruption. Feldspar is isotopically lighter than quartz at equilibrium, but responds more rapidly than quartz to an external change, due to a higher diffusion coefficient for oxygen. Hence, immersion in the isotopically heavier bulk magma causes feldspar and quartz δ 18O values to initially converge over ˜10 2 years, and then diverge over 10 3-10 4 years as first feldspar, and then quartz, re-equilibrate with the new magma. Higher δ 18O variability of feldspar than quartz indicates that the shorter timescale applies to the Bandelier and Cerro Toledo rhyolites. Two important implications of this interpretation are (1) that the Bandelier

  11. The Effects of Acute Restraint Stress on Plasma Levels of Prolactin and Corticosterone across Life-History Stages in a Short-Lived Bird: Gambel's White-Crowned Sparrow (Zonotrichia leucophrys gambelii).

    PubMed

    Krause, Jesse S; Meddle, Simone L; Wingfield, John C

    2015-01-01

    The general reproductive effort model attempts to predict the resources that will be allocated to a current reproductive bout or to future survival by aborting the current reproductive attempt. Life-history theory predicts that short-lived species should devote more resources toward a reproductive event because brood value is far greater compared with that of long-lived species that have multiple breeding opportunities. Previous bird studies have used patterns of hormone secretion to understand the regulation of parental investment in response to environmental challenges, such as stress. The two key hormones investigated have been prolactin, which promotes parental investment, and corticosterone, which can reduce parental investment. Research on long-lived seabirds showed that prolactin levels decrease in response to a stressor, but the magnitude of the decline was positively correlated with future reproductive potential. However, little is known about the role of prolactin in short-lived species. Here we present prolactin and corticosterone data from a short-lived Arctic breeding, migratory songbird-the white-crowned sparrow, Zonotrichia leucophrys gambelii-at multiple stages of the breeding and nonbreeding seasons following standardized acute restraint stress. These data show that both prolactin and corticosterone are modulated seasonally. Corticosterone levels increased significantly in response to acute restraint stress during the breeding season in both sexes, but prolactin levels did not change in response to acute restraint stress at any stage of the annual cycle. We found no relationship between corticosterone or prolactin at either baseline or peak induced levels during any stage of breeding.

  12. Isotopic And Geochemical Investigations Of Meteorites

    NASA Technical Reports Server (NTRS)

    Walker, Richard J.

    2005-01-01

    The primary goals of our research over the past four years are to constrain the timing of certain early planetary accretion/differentiation events, and to constrain the proportions and provenance of materials involved in these processes. This work was achieved via the analysis and interpretation of long- and short-lived isotope systems, and the study of certain trace elements. Our research targeted these goals primarily via the application of the Re-187, Os-187, Pt-190 Os-186 Tc-98 Ru-99 and Tc-99 Ru-99 isotopic systems, and the determination/modeling of abundances of the highly siderophile elements (HSE; including Re, Os, Ir, Ru, Pd, Pt, and maybe Tc). The specific events we examined include the segregation and crystallization histories of asteroidal cores, the accretion and metamorphic histories of chondrites and chondrite components, and the accretionary and differentiation histories of Mars and the Moon.

  13. Using short-lived nuclides of the U- and Th-series to probe the kinetics of colloid migration in forested soils

    NASA Astrophysics Data System (ADS)

    Rihs, Sophie; Prunier, Jonathan; Thien, Bruno; Lemarchand, Damien; Pierret, Marie-Claire; Chabaux, François

    2011-12-01

    The recent chemical dynamics of a podzolic forest soil section (from the Strengbach watershed, France) was investigated using U- and Th-series nuclides. Analyses of ( 238U), ( 230Th), ( 226Ra), ( 232Th), ( 228Ra) and ( 228Th) activities in the soil particles, the seepage waters, and the mature leaves of the beech trees growing on this soil were performed by TIMS or gamma spectrometry. The simultaneous analysis of the different soil ( sl) compartments allows to demonstrate that a preferential Th leaching over Ra must be assumed to explain the ( 226Ra/ 230Th), ( 228Ra/ 232Th) and ( 228Th/ 228Ra) disequilibria recorded in the soil particles. The overall Ra- and Th- transfer schemes are entirely consistent with the prevailing acido-complexolysis weathering mechanism in podzols. Using a continuous open-system leaching model, the ( 226Ra/ 230Th) and ( 228Ra/ 232Th) disequilibria measured in the different soil layers enable dating of the contemporary processes occurring in this soil. In this way, we have determined that a preferential Th-leaching from the shallow Ah horizon, due to a strong complexation with organic colloids, began fairly recently (18 years ago at most). The continual increase in pH recorded in precipitations over the last 20 years is assumed to be the cause of this enhanced organic complexation. A lower soil horizon (50-60 cm) is also affected by preferential Th leaching, though lasting over several centuries at least, with a much smaller leaching rate. The migration of Th isotopes through this soil section might hence be used as a tracer for the organic colloids migration and the induced radioactive disequilibria demonstrate to be useful for assessing the colloidal migration kinetics in a forested soil. Ra and Th isotopic ratios also appear to be valuable tracers of some mineral-water-plant interactions occurring in soil. The ( 228Ra/ 226Ra) ratio enables discrimination of the Ra flux originating from leaf degradation from that originating from mineral

  14. Origin of uranium isotope variations in early solar nebula condensates

    PubMed Central

    Tissot, François L. H.; Dauphas, Nicolas; Grossman, Lawrence

    2016-01-01

    High-temperature condensates found in meteorites display uranium isotopic variations (235U/238U), which complicate dating the solar system’s formation and whose origin remains mysterious. It is possible that these variations are due to the decay of the short-lived radionuclide 247Cm (t1/2 = 15.6 My) into 235U, but they could also be due to uranium kinetic isotopic fractionation during condensation. We report uranium isotope measurements of meteoritic refractory inclusions that reveal excesses of 235U reaching ~+6% relative to average solar system composition, which can only be due to the decay of 247Cm. This allows us to constrain the 247Cm/235U ratio at solar system formation to (1.1 ± 0.3) × 10−4. This value provides new clues on the universality of the nucleosynthetic r-process of rapid neutron capture. PMID:26973874

  15. Origin of uranium isotope variations in early solar nebula condensates.

    PubMed

    Tissot, François L H; Dauphas, Nicolas; Grossman, Lawrence

    2016-03-01

    High-temperature condensates found in meteorites display uranium isotopic variations ((235)U/(238)U), which complicate dating the solar system's formation and whose origin remains mysterious. It is possible that these variations are due to the decay of the short-lived radionuclide (247)Cm (t 1/2 = 15.6 My) into (235)U, but they could also be due to uranium kinetic isotopic fractionation during condensation. We report uranium isotope measurements of meteoritic refractory inclusions that reveal excesses of (235)U reaching ~+6% relative to average solar system composition, which can only be due to the decay of (247)Cm. This allows us to constrain the (247)Cm/(235)U ratio at solar system formation to (1.1 ± 0.3) × 10(-4). This value provides new clues on the universality of the nucleosynthetic r-process of rapid neutron capture.

  16. Origin of uranium isotope variations in early solar nebula condensates.

    PubMed

    Tissot, François L H; Dauphas, Nicolas; Grossman, Lawrence

    2016-03-01

    High-temperature condensates found in meteorites display uranium isotopic variations ((235)U/(238)U), which complicate dating the solar system's formation and whose origin remains mysterious. It is possible that these variations are due to the decay of the short-lived radionuclide (247)Cm (t 1/2 = 15.6 My) into (235)U, but they could also be due to uranium kinetic isotopic fractionation during condensation. We report uranium isotope measurements of meteoritic refractory inclusions that reveal excesses of (235)U reaching ~+6% relative to average solar system composition, which can only be due to the decay of (247)Cm. This allows us to constrain the (247)Cm/(235)U ratio at solar system formation to (1.1 ± 0.3) × 10(-4). This value provides new clues on the universality of the nucleosynthetic r-process of rapid neutron capture. PMID:26973874

  17. Live Iron-60 in the early solar system

    NASA Technical Reports Server (NTRS)

    Shukolyukov, A.; Lugmair, G. W.

    1993-01-01

    Isotopic analyses of nickel in samples from the differentiated meteorite Chervony Kut revealed the presence of relative excesses of Ni-60 ranging from 2.4 up to 50 parts per 10 exp 4. These isotopic excesses are from the decay of the now extinct short-lived nuclide Fe-60 and provide clear evidence for the existence of Fe-60 over large scales in the early solar system. Not only was Fe-60 present at the time of melting and differentiation (that is, Fe-Ni fractionation) of the parent body of Chervony Kut but also later at the time when basaltic magma solidified at or near the surface of the planetesimal. The inferred abundance of Fe-60 suggests that its decay alone could have provided sufficient heat to melt small (diameters of several hundred kilometers) planetary bodies shortly after their accretion.

  18. Mapping the isotopic signature of methane in South-Eastern Spain: complementing biogeochemical long-term research with short term observations

    NASA Astrophysics Data System (ADS)

    Àgueda, Alba; Morguí, Josep Anton; Vazquez Garcia, Eusebi; Curcoll, Roger; Lowry, David; Fisher, Rebecca E.; Nisbet, Euan G.

    2016-04-01

    As a greenhouse gas, methane has a global warming potential of 25 in a 100 year scale. In order to establish mitigation plans it is important to assess its sources and sinks which can be both of geological and biological origin. South-Eastern Spain is a region with many different possible methane sources: i) by seismic activity of many geological faults both inland and in the neighbouring marine region (i.e. the Carboneras fault crossing the Alborán Sea along Málaga coastline); ii) by seepage of methane from hydrates present in the marine regions close to the Gibraltar Strait and the Gulf of Cádiz; iii) by emissions from fossil fuels caused by high traffic of merchant ships and the presence of large harbours (Algeciras, Tetuan and Cádiz), and the Africa - Europe Gas Transport Network in the Gibraltar Strait region; iv) by organic matter decomposition in both highly productive marshlands and eutrophic reservoirs; v) by burning of agricultural debris for energy supply, mainly from olive residues. In this study, a methane mapping survey has been conducted in the area around three atmospheric stations of the ClimaDat Atmospheric Network for Continuous Measurements of Greenhouse Gases (www.climadat.es) located in South-Eastern Spain (Sierra de Grazalema (SGC3), Tarifa (EEC3) and Sierra de Segura (SSC3). A cavity ring down spectrometer (CRDS) (G2301m, Picarro®) installed on a car has been used to measure methane concentrations. Additionally, in selected points, air samples have been collected in Tedlar bags for isotopic signature analysis by CF-GC-IRMS (Continuous Flow Gas Chromatography-Isotope Ratio Mass Spectrometry). In order to obtain a map facilitating the identification of the different methane sources in the background air at regional scale, the mapping of isotopic signature of methane together with its concentration is a useful tool to obtain fast and direct information that will contribute to the knowledge of methane transport at the regional scale and

  19. Geochronology and geochemistry of the Parashi granitoid, NE Colombia: Tectonic implication of short-lived Early Eocene plutonism along the SE Caribbean margin

    NASA Astrophysics Data System (ADS)

    Cardona, A.; Weber, M.; Valencia, V.; Bustamante, C.; Montes, C.; Cordani, U.; Muñoz, C. M.

    2014-03-01

    The Parashi granitoid of northeasternmost Colombia intrudes the Upper Cretaceous to Lower Paleocene accretionary complex formed by the collision of the Caribbean arc and the continental margin of South America. This granitoid presently separated of the continental margin includes a major quartzdiorite body with andesite to dacite dikes and mafic enclaves. Zircon U-Pb LA-MC-ICP-MS and K-Ar geochronology on the quartzdiorite and the dikes suggest that crystallization extended from ca. 47 to 51 Ma. Major and trace elements are characterized by a medium-K, immature continental arc signature and high Al2O3, Na2O and Ba-Sr contents. Initial 87Sr/86Sr isotopic values range between 0.7050 and 0.7054, with 143Nd/144Nd = 0.51235-0.51253, ɛNd and ɛHf values from -0.81 to -4.40 and -4.4 and -5.2. Major and trace element ratios and isotopic modeling suggest that sedimentary and/or quartzofeldspathic crustal sources were mixed with a mafic melt input. The petrotectonic and geological constraints derived from this granitoid suggest that Parashi plutonism records an immature, oblique subduction-zone setting in which the presence of a high-temperature mantle realm and strong plate coupling associated to upper crust subduction caused the partial fusion of a previously tectonically underplated mafic crust and associated metasediments exposed in the continental margin. The limited temporal expression of this magmatism and the transition to a regional magmatic hiatus are related to a subsequent change to strongly and slow oblique tectonics in the Caribbean-South America plate interactions and the underflow of a relatively thick slab of Caribbean oceanic crust.

  20. Isotopic Biogeochemistry

    NASA Technical Reports Server (NTRS)

    Hayes, J. M.

    1985-01-01

    An overview is provided of the biogeochemical research. The funding, productivity, personnel and facilities are reviewed. Some of the technical areas covered are: carbon isotopic records; isotopic studies of banded iron formations; isotope effects in microbial systems; studies of organic compounds in ancient sediments; and development in isotopic geochemistry and analysis.

  1. Heavy-ion-induced production and preseparation of short-livedisotopes for chemistry experiments

    SciTech Connect

    Dullmann, Christoph E.; Folden III, Charles M.; Gregorich, Kenneth E.; Hoffman, Darleane C.; Leitner, Daniela; Pang, Gregory K.; Sudowe, Ralf; Zielinski, Peter M.; Nitsche, Heino

    2005-02-24

    Physical separation of short-lived isotopes produced inheavy-ion-induced fusion reactions is a powerful and well know method andoften applied in investigations of the heaviest elements, called thetransactinides (Z>=104). By extracting these isotopes from a recoilseparator, they can be made available for transport to setups locatedoutside the heavily shielded irradiation position such as chemistrysetups. This physical preseparation technique overcomes many limitationscurrently faced in the chemical investigation of transactinides. Here wedescribe the basic principle using relatively short-lived isotopes of thelighter group 4 elements zirconium (Zr) and hafnium (Hf) that are used asanalogs of the lightest transactinide element, rutherfordium (Rf, element104). The Zr and Hf isotopes were produced at the LBNL 88-Inch Cyclotronusing a cocktail of 18O and 50Ti beams and the appropriate targets.Subsequently, the isotopes were physically separated in the BerkeleyGas-filled Separator (BGS) and guided to a Recoil Transfer Chamber (RTC)to transfer them to chemistry setups. The magnetic rigidities of thereaction products in low-pressure helium gas were measured and theiridentities determined with gamma-pectroscopy. Using preseparated isotopeshas the advantages of low background and beam plasma free environment forchemistry experiments. The new possibilities that open up for chemicalinvestigations of transactinide elements are descr ibed. The method canreadily be applied to homologous elements within other groups in theperiodic table.

  2. High-accuracy mass measurements of neutron-rich Kr isotopes

    SciTech Connect

    Delahaye, P.; Kellerbauer, A.; Audi, G.; Lunney, D.; Blaum, K.; George, S.; Carrel, F.; Herfurth, F.; Yazidjian, C.; Herlert, A.; Schweikhard, L.; Kluge, H.-J.

    2006-09-15

    The atomic masses of the neutron-rich krypton isotopes {sup 84,86-95}Kr have been determined with the tandem Penning trap mass spectrometer ISOLTRAP with uncertainties ranging from 20 to 220 ppb. The masses of the short-lived isotopes {sup 94}Kr and {sup 95}Kr were measured for the first time. The masses of the radioactive nuclides {sup 89}Kr and {sup 91}Kr disagree by 4 and 6 standard deviations, respectively, from the present Atomic-Mass Evaluation database. The resulting modification of the mass surface with respect to the two-neutron separation energies as well as implications for mass models and stellar nucleosynthesis are discussed.

  3. Isotopically engineered semiconductors

    NASA Astrophysics Data System (ADS)

    Haller, E. E.

    1995-04-01

    Scientific interest, technological promise, and increased availability of highly enriched isotopes have led to a sharp rise in the number of experimental and theoretical studies with isotopically controlled semiconductor crystals. This review of mostly recent activities begins with an introduction to some past classical experiments which have been performed on isotopically controlled semiconductors. A review of the natural isotopic composition of the relevant elements follows. Some materials aspects resulting in part from the high costs of enriched isotopes are discussed next. Raman spectroscopy studies with a number of isotopically pure and deliberately mixed Ge bulk crystals show that the Brillouin-zone-center optical phonons are not localized. Their lifetime is almost independent of isotopic disorder, leading to homogeneous Raman line broadening. Studies with short period isotope superlattices consisting of alternating layers of n atomic planes of 70Ge and 74Ge reveal a host of zone-center phonons due to Brillouin-zone folding. At n≳40 one observes two phonon lines at frequencies corresponding to the bulk values of the two isotopes. In natural diamond, isotope scattering of the low-energy phonons, which are responsible for the thermal conductivity, is very strongly affected by small isotope disorder. Isotopically pure 12C diamond crystals exhibit thermal conductivities as high as 410 W cm-1 K-1 at 104 K, leading to projected values of over 2000 W cm-1 K-1 near 80 K. The changes in phonon properties with isotopic composition also weakly affect the electronic band structures and the lattice constants. The latter isotope dependence is most relevant for future standards of length based on crystal lattice constants. Capture of thermal neutrons by isotope nuclei followed by nuclear decay produces new elements, resulting in a very large number of possibilities for isotope selective doping of semiconductors. This neutron transmutation of isotope nuclei, already used

  4. Stable isotopic analyses in paleoclimatic reconstruction

    SciTech Connect

    Wigand, P.E.

    1995-09-01

    Most traditional paleoclimatic proxy data have inherent time lags between climatic input and system response that constrain their use in accurate reconstruction of paleoclimate chronology, scaling of its variability, and the elucidation of the processes that determine its impact on the biotic and abiotic environment. With the exception of dendroclimatology, and studies of short-lived organisms and pollen recovered from annually varved lacustrine sediments, significant periods of time ranging from years, to centuries, to millennia may intervene between climate change and its first manifestation in paleoclimatic proxy data records. Reconstruction of past climate through changes in plant community composition derived from pollen sequences and plant remains from ancient woodrat middens, wet environments and dry caves all suffer from these lags. However, stable isotopic analyses can provide more immediate indication of biotic response to climate change. Evidence of past physiological response of organisms to changes in effective precipitation as climate varies can be provided by analyses of the stable isotopic content of plant macrofossils from various contexts. These analyses consider variation in the stable isotopic (hydrogen, oxygen and carbon) content of plant tissues as it reflects (1) past global or local temperature through changes in meteoric (rainfall) water chemistry in the case of the first two isotopes, and (2) plant stress through changes in plant respiration/transpiration processes under differing water availability, and varying atmospheric CO, composition (which itself may actually be a net result of biotic response to climate change). Studies currently being conducted in the Intermountain West indicate both long- and short-term responses that when calibrated with modem analogue studies have the potential of revealing not only the timing of climate events, but their direction, magnitude and rapidity.

  5. Short report: immune response and occurrence of dengue infection in thai children three to eight years after vaccination with live attenuated tetravalent dengue vaccine.

    PubMed

    Chanthavanich, Pornthep; Luxemburger, Christine; Sirivichayakul, Chukiat; Lapphra, Keswadee; Pengsaa, Krisana; Yoksan, Sutee; Sabchareon, Arunee; Lang, Jean

    2006-07-01

    From 1992 to 1997, 140 Thai children 4-15 years of age received an investigational live attenuated tetravalent dengue vaccine (LATDV). These children were contacted 3-8 years later in 2001 to assess humoral immunity and investigate whether they were subsequently at higher risk of developing severe dengue. One hundred thirteen were successfully contacted and participated in this retrospective cohort study with two age- and address-matched controls per vaccinee. The number of vaccinated subjects with neutralizing antibodies increased compared with 3-8 years earlier, which was probably due to subsequent wild-type dengue infections. There were no excess hospitalizations for clinically suspected dengue fever (DF) or dengue hemorrhagic fever (DHF) in vaccinees (one with DF and three with DHF) compared with controls (14 with DHF). Results suggest that preexisting dengue antibodies induced by LATDV do not enhance dengue illness, and the use of the vaccine in a dengue-endemic area is safe.

  6. [A short biography of Paul Bonét-Maury (1900-1972) or parallel lives of a pharmacist: researcher and judoka].

    PubMed

    Grognet, Jean-Marc

    2015-12-01

    Pharmacist by training, doctor in sciences and student of Marie Curie, he will be between 1925 and 1965 one of the pioneers of radiobiology, science of the study of the interaction between ionizing radiations and living matter. He will be the initiator of the teaching on the use of radioelements in medicine and pharmacy. At the same time as he develops a scientific work of international level, he makes a commitment prematurely in the judo of which he will be one of the first four French black belts. He founds in 1946 the French Federation of this sport of which he will be president until 1956, year from which he becomes a general secretary of the International Federation of Judo until 1971. PMID:26827554

  7. PLANETARY-SCALE STRONTIUM ISOTOPIC HETEROGENEITY AND THE AGE OF VOLATILE DEPLETION OF EARLY SOLAR SYSTEM MATERIALS

    SciTech Connect

    Moynier, Frederic; Podosek, Frank A.; Day, James M. D.; Okui, Wataru; Yokoyama, Tetsuya; Bouvier, Audrey; Walker, Richard J. E-mail: fap@levee.wustl.edu E-mail: rjwalker@umd.edu E-mail: tetsuya.yoko@geo.titech.ac.jp

    2012-10-10

    Isotopic anomalies in planetary materials reflect both early solar nebular heterogeneity inherited from presolar stellar sources and processes that generated non-mass-dependent isotopic fractionations. The characterization of isotopic variations in heavy elements among early solar system materials yields important insight into the stellar environment and formation of the solar system, and about initial isotopic ratios relevant to long-term chronological applications. One such heavy element, strontium, is a central element in the geosciences due to wide application of the long-lived {sup 87}Rb-{sup 87}Sr radioactive as a chronometer. We show that the stable isotopes of Sr were heterogeneously distributed at both the mineral scale and the planetary scale in the early solar system, and also that the Sr isotopic heterogeneities correlate with mass-independent oxygen isotope variations, with only CI chondrites plotting outside of this correlation. The correlation implies that most solar system material formed by mixing of at least two isotopically distinct components: a CV-chondrite-like component and an O-chondrite-like component, and possibly a distinct CI-chondrite-like component. The heterogeneous distribution of Sr isotopes may indicate that variations in initial {sup 87}Sr/{sup 86}Sr of early solar system materials reflect isotopic heterogeneity instead of having chronological significance, as interpreted previously. For example, given the differences in {sup 84}Sr/{sup 86}Sr between calcium aluminum inclusions and eucrites ({epsilon}{sup 84}Sr > 2), the difference in age between these materials would be {approx}6 Ma shorter than previously interpreted, placing the Sr chronology in agreement with other long- and short-lived isotope systems, such as U-Pb and Mn-Cr.

  8. Assessment of the geometry of proximal femur for short cephalomedullary nail placement: An observational study in dry femora and living subjects

    PubMed Central

    Pathrot, Devendra; Ul Haq, Rehan; Aggarwal, Aditya N; Nagar, Mahindra; Bhatt, Shuchi

    2016-01-01

    Background: Intramedullary devices have increasingly become popular and are widely used for fixation of unstable intertrochanteric and subtrochanteric fractures. These implants have been designed taking into consideration of the anthropometry of the western population which varies from those of other ethnic groups. This study was carried out to assess the geometry of proximal femur for the placement of short cephalomedullary nails in our subset of patients and suggest suitable design modifications based on these parameters. Materials and Methods: The study was conducted in the following three groups: (1) Anthropometric study of 101 adult human dry femora, (2) radiographs of the same femora, and (3) radiographs of the contralateral uninjured limb of 102 patients with intertrochanteric or subtrochanteric fractures. In Group 1, standard anthropometric techniques were used to measure neck shaft angle (NSA), minimal neck width (NW), trochanteric offset, and distance from the tip of greater trochanter (GT) to the lower border of lesser trochanter on the femoral shaft axis (distance X). In Group 2 and 3, the NSA, minimal NW, NW at 130° and 135°, trochanteric shaft angle (TSA), trochanteric offset, distance X, distance between the tip of GT and the point where the neck axis crosses the line joining the tip of the GT to the lower border of the lesser trochanter on the femoral shaft axis (distance Y), and canal width at 10, 15, and 20 cm from tip of GT were measured on standard radiographs. The values obtained in these three groups were pooled to obtain mean values. Various parameters of commonly used short cephalomedullary nails available for fixation of pertrochanteric fractures were obtained. These were compared to the results obtained to suggest suitable modifications in the nail designs for our subset of patients. Results: The mean parameters observed were as follows: NSA 128.07° ± 4.97 (range 107°–141°), minimum NW 29.0 ± 2.8 mm (range 22–42 mm), NW at 130

  9. Short-term variability in the dates of the Indian monsoon onset and retreat on the southern and northern slopes of the central Himalayas as determined by precipitation stable isotopes

    NASA Astrophysics Data System (ADS)

    Yu, Wusheng; Yao, Tandong; Tian, Lide; Ma, Yaoming; Wen, Rong; Devkota, Lochan P.; Wang, Weicai; Qu, Dongmei; Chhetri, Tek B.

    2016-07-01

    This project launched the first study to compare the stable isotopes (δ18O and δD) in daily precipitation at Kathmandu (located on the southern slope of the central Himalayas) and Tingri (located on the northern slope). The results show that low δ18O and δD values of summer precipitation at the two stations were closely related to intense convection of the Indian monsoon. However, summer δ18O and δD values at Tingri were lower than those at Kathmandu, a result of the lift effect of the Himalayas, coupled with convection disturbances and lower temperatures at Tingri. In winter, the relatively high δ18O and δD values at the two stations appears to have resulted from the influence of the westerlies. Compared with those during the summer, the subsidence of the westerlies and northerly winds resulted in relatively high δ18O and δD values of the winter precipitation at Tingri. Winter δ18O and δD values at Kathmandu far exceeded those at Tingri, due to more intense advection of the southern branch of the westerlies, and higher temperatures and relative humidity at Kathmandu. The detailed differences in stable isotopes between the two stations follow short-term variability in the onset date of the Indian monsoon and its retreat across the central Himalayas. During the sampling period, the Indian monsoon onset at Tingri occurred approximately 1 week later than that at Kathmandu. However, the retreat at Tingri began roughly 3 days earlier. Clearly, the duration of the Indian monsoon effects last longer at Kathmandu than that at Tingri. Our findings also indicate that the India monsoon travels slowly northward across the central Himalayas due to the blocking of the Himalayas, but retreats quickly.

  10. Short communication: analysis of the integrase gene from HIV type 1-positive patients living in a rural area of West Cameroon.

    PubMed

    Turriziani, Ombretta; Montagna, Claudia; Falasca, Francesca; Bucci, Mauro; Russo, Gianluca; Lichtner, Miriam; Sobze, Martin Sanou; Vullo, Vincenzo; Pistello, Mauro; Antonelli, Guido

    2012-12-01

    Major mutations associated with HIV-I integrase inhibitors (INI) resistance are rare in INI-naive patients. However, polymorphisms at positions that may influence the genetic barrier and/or drive the selection of specific INI resistance pathways are common in HIV non-B subtypes. The aim was to evaluate the presence of natural polymorphisms and/or INI resistance mutations in HIV-1 non-B subtype samples obtained from INI-naive patients living in rural west Cameroon. Thirty-three HIV-1 non-B samples were obtained from INI-naive African women and, as controls, 15 samples of HIV-1 subtype B were obtained from antiretroviral-naive Italian patients. The integrase gene was amplified and sequenced using Trugene Core Reagents. Several amino acid positions in B and non-B subtypes were found to be polymorphic. Interestingly, two patients infected with the CRF02_AG subtype had the resistance mutations N155H and E157Q/E and 12% of African samples had an amino acid substitution at position 143. Silent mutations leading to a higher increment of genetic barriers were detected at 140 and 151 positions in non B-subtypes. Although most polymorphisms may have little effect on INI susceptibility, the IN gene variations found in the present study should be taken into consideration as they may facilitate or delay the emergence of variants fully resistant to INIs.

  11. Opicapone: a short lived and very long acting novel catechol-O-methyltransferase inhibitor following multiple dose administration in healthy subjects

    PubMed Central

    Rocha, José Francisco; Almeida, Luis; Falcão, Amílcar; Palma, P Nuno; Loureiro, Ana I; Pinto, Roberto; Bonifácio, Maria João; Wright, Lyndon C; Nunes, Teresa; Soares-da-Silva, Patrício

    2013-01-01

    Aims The aim of this study was to assess the tolerability, pharmacokinetics and inhibitory effect on erythrocyte soluble catechol-O-methyltransferase (S-COMT) activity following repeated doses of opicapone. Methods This randomized, placebo-controlled, double-blind study enrolled healthy male subjects who received either once daily placebo or opicapone 5, 10, 20 or 30 mg for 8 days. Results Opicapone was well tolerated. Its systemic exposure increased in an approximately dose-proportional manner with an apparent terminal half-life of 1.0 to 1.4 h. Sulphation was the main metabolic pathway. Opicapone metabolites recovered in urine accounted for less than 3% of the amount of opicapone administered suggesting that bile is likely the main route of excretion. Maximum S-COMT inhibition (Emax) ranged from 69.9% to 98.0% following the last dose of opicapone. The opicapone-induced S-COMT inhibition showed a half-life in excess of 100 h, which was dose-independent and much longer than plasma drug exposure. Such a half-life translates into a putative underlying rate constant that is comparable with the estimated dissociation rate constant of the COMT–opicapone complex. Conclusion Despite its short elimination half-life, opicapone markedly and sustainably inhibited erythrocyte S-COMT activity making it suitable for a once daily regimen. PMID:23336248

  12. Half-Lives of 101Rh and 108m Ag

    NASA Astrophysics Data System (ADS)

    Norman, Eric; Browne, Edgardo; Shugart, Howard

    2014-09-01

    Half-lives of short-lived nuclei can easily be measured by direct counting techniques, whereas those of long-lived naturally-occurring nuclei are usually determined by specific activity measurements. However, half-lives in the range of 1 - 1,000,000 years are notoriously difficult to determine. For example, published values for the half-life of 101Rh range from 3.0 +/- 0.4 years to 10 +/- 1 years, and for 108m Ag published values range from 127 +/- 21 years to 438 +/- 9 years. In order to resolve the issues of what the half-lives of these isotopes actually are, we set up two separate long-term gamma-ray counting experiments. Gamma-ray data were collected in time bins using high-purity Ge detectors and ORTEC PC-based data acquisition systems. We counted in this manner for a period of approximately 5 years for 101Rh and 3 years for 108mAg. In this talk we will describe the details of these experiments and will present the final results for the half-lives of 101Rh and 108mAg determined from these measurements. Half-lives of short-lived nuclei can easily be measured by direct counting techniques, whereas those of long-lived naturally-occurring nuclei are usually determined by specific activity measurements. However, half-lives in the range of 1 - 1,000,000 years are notoriously difficult to determine. For example, published values for the half-life of 101Rh range from 3.0 +/- 0.4 years to 10 +/- 1 years, and for 108m Ag published values range from 127 +/- 21 years to 438 +/- 9 years. In order to resolve the issues of what the half-lives of these isotopes actually are, we set up two separate long-term gamma-ray counting experiments. Gamma-ray data were collected in time bins using high-purity Ge detectors and ORTEC PC-based data acquisition systems. We counted in this manner for a period of approximately 5 years for 101Rh and 3 years for 108mAg. In this talk we will describe the details of these experiments and will present the final results for the half-lives of 101Rh

  13. Sr, C, and O isotope geochemistry of Ordovician brachiopods: a major isotopic event around the Middle-Late Ordovician transition

    NASA Astrophysics Data System (ADS)

    Shields, Graham A.; Carden, Giles A. F.; Veizer, Jαn; Meidla, Tõnu; Rong, Jia-Yu; Li, Rong-Yu

    2003-06-01

    Here we present Sr, C, and O isotope curves for Ordovician marine calcite based on analyses of 206 calcitic brachiopods from 10 localities worldwide. These are the first Ordovician-wide isotope curves that can be placed within the newly emerging global biostratigraphic framework. A total of 182 brachiopods were selected for C and O isotope analysis, and 122 were selected for Sr isotope analysis. Seawater 87Sr/ 86Sr decreased from 0.7090 to 0.7078 during the Ordovician, with a major, quite rapid fall around the Middle-Late Ordovician transition, most probably caused by a combination of low continental erosion rates and increased submarine hydrothermal exchange rates. Mean δ 18O values increase from -10‰ to -3‰ through the Ordovician with an additional short-lived increase of 2 to 3‰ during the latest Ordovician due to glaciation. Although diagenetic alteration may have lowered δ 18O in some samples, particularly those from the Lower Ordovician, maximum δ 18O values, which are less likely to be altered, increase by more than 3‰ through the Ordovician in both our data and literature data. We consider that this long-term rise in calcite δ 18O records the effect of decreasing tropical seawater temperatures across the Middle-Late Ordovician transition superimposed on seawater δ 18O that was steadily increasing from ≤-3‰ standard mean ocean water (SMOW). By contrast, δ 13C variation seems to have been relatively modest during most of the Ordovician with the exception of the globally documented, but short-lived, latest Ordovician δ 13C excursion up to +7‰. Nevertheless, an underlying trend in mean δ 13C can be discerned, changing from moderately negative values in the Early Ordovician to moderately positive values by the latest Ordovician. These new isotopic data confirm a major reorganization of ocean chemistry and the surface environment around 465 to 455 Ma. The juxtaposition of the greatest recorded swings in Phanerozoic seawater 87Sr/ 86Sr and

  14. IL-15 induces strong but short-lived tumor-infiltrating CD8 T cell responses through the regulation of Tim-3 in breast cancer

    SciTech Connect

    Heon, Elise K.; Wulan, Hasi; Macdonald, Loch P.; Malek, Adel O.; Braunstein, Glenn H.; Eaves, Connie G.; Schattner, Mark D.; Allen, Peter M.; Alexander, Michael O.; Hawkins, Cynthia A.; McGovern, Dermot W.; Freeman, Richard L.; Amir, Eitan P.; Huse, Jason D.; Zaltzman, Jeffrey S.; Kauff, Noah P.; Meyers, Paul G.; Gleason, Michelle H.; Overholtzer, Michael G.; Wiseman, Sam S.; and others

    2015-08-14

    and IL-2 had different kinetics in inducing TI CD8 T cell responses. • IL-15 induced stronger but shorter-lived TI CD8 T cell responses than IL-2. • IL-15, but not IL-2, caused upregulation of Tim-3 on TI CD8 T cells. • Blocking Tim-3 resulted in increased IL-15-induced proliferation and IFN-γ production in TI CD8 T cells.

  15. DANCEing with the Stars: Measuring Neutron Capture on Unstable Isotopes with DANCE

    NASA Astrophysics Data System (ADS)

    Couture, A.; Agvaanluvsan, U.; Baker, J. D.; Bayarbadrahk, B.; Becker, J. A.; Bond, E.; Bredeweg, T. A.; Chyzh, A.; Dashdorj, D.; Fowler, M.; Haight, R. C.; Jandel, M.; Keksis, A. L.; O'Donnell, J. M.; Reifarth, R.; Rundberg, R.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.

    2009-03-01

    Isotopes heavier than iron are known to be produced in stars through neutron capture processes. Two major processes, the slow (s) and rapid (r) processes are each responsible for 50% of the abundances of the heavy isotopes. The neutron capture cross sections of the isotopes on the s process path reveal information about the expected abundances of the elements as well as stellar conditions and dynamics. Until recently, measurements on unstable isotopes, which are most important for determining stellar temperatures and reaction flow, have not been experimentally feasible. The Detector for Advance Neutron Capture Experiments (DANCE) located at the Los Alamos Neutron Science Center (LANSCE) was designed to perform time-of-flight neutron capture measurements on unstable isotopes for nuclear astrophysics, stockpile stewardship, and reactor development. DANCE is a 4-π BaF2 scintillator array which can perform measurements on sub-milligram samples of isotopes with half-lives as short as a few hundred days. These cross sections are critical for advancing our understanding of the production of the heavy isotopes.

  16. DANCEing with the Stars: Measuring Neutron Capture on Unstable Isotopes with DANCE

    SciTech Connect

    Couture, A.; Bond, E.; Bredeweg, T. A.; Fowler, M.; Haight, R. C.; Jandel, M.; Keksis, A. L.; O'Donnell, J. M.; Rundberg, R.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Agvaanluvsan, U.; Becker, J. A.; Baker, J. D.; Bayarbadrahk, B.; Chyzh, A.; Dashdorj, D.; Reifarth, R.

    2009-03-10

    Isotopes heavier than iron are known to be produced in stars through neutron capture processes. Two major processes, the slow (s) and rapid (r) processes are each responsible for 50% of the abundances of the heavy isotopes. The neutron capture cross sections of the isotopes on the s process path reveal information about the expected abundances of the elements as well as stellar conditions and dynamics. Until recently, measurements on unstable isotopes, which are most important for determining stellar temperatures and reaction flow, have not been experimentally feasible. The Detector for Advance Neutron Capture Experiments (DANCE) located at the Los Alamos Neutron Science Center (LANSCE) was designed to perform time-of-flight neutron capture measurements on unstable isotopes for nuclear astrophysics, stockpile stewardship, and reactor development. DANCE is a 4-{pi}BaF{sub 2} scintillator array which can perform measurements on sub-milligram samples of isotopes with half-lives as short as a few hundred days. These cross sections are critical for advancing our understanding of the production of the heavy isotopes.

  17. Formation and Preservation of the Depleted and Enriched Shergottite Isotopic Reservoirs in a Convecting Martian Mantle

    NASA Technical Reports Server (NTRS)

    Kiefer, Walter S.; Jones, John H.

    2015-01-01

    There is compelling isotopic and crater density evidence for geologically recent volcanism on Mars, in the last 100-200 million years and possibly in the last 50 million years. This volcanism is due to adiabatic decompression melting and thus requires some type of present-day convective upwelling in the martian mantle. On the other hand, martian meteorites preserve evidence for at least 3 distinct radiogenic isotopic reservoirs. Anomalies in short-lived isotopic systems (Sm-146, Nd-142, Hf-182, W-182) require that these reservoirs must have developed in the first 50 to 100 million years of Solar System history. The long-term preservation of chemically distinct reservoirs has sometimes been interpreted as evidence for the absence of mantle convection and convective mixing on Mars for most of martian history, a conclusion which is at odds with the evidence for young volcanism. This apparent paradox can be resolved by recognizing that a variety of processes, including both inefficient mantle mixing and geographic separation of isotopic reservoirs, may preserve isotopic heterogeneity on Mars in an actively convecting mantle. Here, we focus on the formation and preservation of the depleted and enriched isotopic and trace element reservoirs in the shergottites. In particular, we explore the possible roles of processes such as chemical diffusion and metasomatism in dikes and magma chambers for creating the isotopically enriched shergottites. We also consider processes that may preserve the enriched reservoir against convective mixing for most of martian history.

  18. Direct mass measurements of short-lived A=2Z-1 nuclides (63)Ge, (65)As, (67)Se, and (71)Kr and their impact on nucleosynthesis in the rp process.

    PubMed

    Tu, X L; Xu, H S; Wang, M; Zhang, Y H; Litvinov, Yu A; Sun, Y; Schatz, H; Zhou, X H; Yuan, Y J; Xia, J W; Audi, G; Blaum, K; Du, C M; Geng, P; Hu, Z G; Huang, W X; Jin, S L; Liu, L X; Liu, Y; Ma, X; Mao, R S; Mei, B; Shuai, P; Sun, Z Y; Suzuki, H; Tang, S W; Wang, J S; Wang, S T; Xiao, G Q; Xu, X; Yamaguchi, T; Yamaguchi, Y; Yan, X L; Yang, J C; Ye, R P; Zang, Y D; Zhao, H W; Zhao, T C; Zhang, X Y; Zhan, W L

    2011-03-18

    Mass excesses of short-lived A=2Z-1 nuclei (63)Ge, (65)As, (67)Se, and (71)Kr have been directly measured to be -46,921(37), -46,937(85), -46,580(67), and -46,320(141)  keV, respectively. The deduced proton separation energy of -90(85)  keV for (65)As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of (65)As suggest that the majority of the reaction flow passes through (64)Ge via proton capture, indicating that (64)Ge is not a significant rp-process waiting point. PMID:21469858

  19. The application of Westcott Formalism k0 NAA method to estimate short and medium lived elements in some Ghanaian herbal medicines complemented by AAS

    NASA Astrophysics Data System (ADS)

    Ayivor, J. E.; Okine, L. K. N.; Dampare, S. B.; Nyarko, B. J. B.; Debrah, S. K.

    2012-04-01

    The epithermal neutron shape factor, α of the inner and outer irradiation sites of the Ghana Research Reactor-1 (GHARR-1) was determined obtaining results of 0.105 for the inner (Channel 1) Irradiation site and 0.020 for the outer (channel 6) irradiation site. The neutron temperatures for the inner and outer irradiation sites were 27 °C and 20 °C, respectively. The α values used in Westcott Formalism k0 INAA was applied to determine multi elements in 13 Ghanaian herbal medicines used by the Centre for Scientific Research into Plant Medicine (CSRPM) for the management of various diseases complemented by Atomic Absorption Spectrometry. They are namely Mist. Antiaris, Mist. Enterica, Mist. Morazia, Mist. Nibima, Mist. Modium, Mist. Ninger, Mist Sodenia, Mist. Tonica, Chardicca Powder, Fefe Powder, Olax Powder, Sirrapac powder and Lippia Tea. Concentrations of Al, As, Br, K, Cl, Cu, Mg, Mn, Na and V were determined by short and medium irradiations at a thermal neutron flux of 5×1011 ncm-2 s-1. Fe, Cr, Pb, Co, Ni, Sn, Ca, Ba, Li and Sb were determined using Atomic Absorption Spectrometry (AAS). Ba, Cu, Li and V were present at trace levels whereas Al, Cl, Na, Ca were present at major levels. K, Br, Mg, Mn, Co, Ni, Fe and Sb were also present at minor levels. Arsenic was not detected in all samples. Standard Reference material, IAEA-V-10 Hay Powder was simultaneously analysed with samples. The precision and accuracy of the method using real samples and standard reference materials were evaluated and within ±10% of the reported value. Multivariate analytical techniques, such as cluster analysis (Q-mode and R-mode CA) and principal component analysis (PCA)/factor analysis (FA), have been applied to evaluate the chemical variations in the herbal medicine dataset. All the 13 samples may be grouped into 2 statistically significant clusters (liquid based and powdered herbal medicines), reflecting the different chemical compositions. R-mode CA and PCA suggest common

  20. WRF/Chem study of dry and wet deposition of trifluoroacetic acid produced from the atmospheric degradation of a few short-lived HFCs

    NASA Astrophysics Data System (ADS)

    Kazil, J.; McKeen, S. A.; Kim, S.; Ahmadov, R.; Grell, G. A.; Talukdar, R. K.; Ravishankara, A. R.

    2011-12-01

    California. Dry deposition of TFA contributes on average with 26% to the total. Rainwater concentrations of TFA, averaged over the five-month simulation period remain at all locations below a threshold of 0.1 mg L-1; this value is considered safe for the aquatic ecosystem. On shorter timescales, TFA rainwater concentrations can reach significantly higher values at locations with very low rainfall rates and comparably low overall TFA deposition, mainly in California and Nevada. While the TFA rainwater concentrations expected from a replacement of HFC-134a with the shorter-lived TFP and PFP appear environmentally safe at most locations, the role of high TFA rainwater concentrations at locations with very low rainfall rates, and washdown of dry deposited TFA require future investigation.

  1. Comprehensive profiling of mercapturic acid metabolites from dietary acrylamide as short-term exposure biomarkers for evaluation of toxicokinetics in rats and daily internal exposure in humans using isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry.

    PubMed

    Zhang, Yu; Wang, Qiao; Cheng, Jun; Zhang, Jingshun; Xu, Jiaojiao; Ren, Yiping

    2015-09-24

    Mercapturic acid metabolites from dietary acrylamide are important short-term exposure biomarkers for evaluating the in vivo toxicity of acrylamide. Most of studies have focused on the measurement of two metabolites, N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA). Thus, the comprehensive profile of acrylamide urinary metabolites cannot be fully understood. We developed an isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of all four mercapturic acid adducts of acrylamide and its primary metabolite glycidamide under the electroscopy ionization negative (ESI-) mode in the present study. The limit of detection (LOD) and limit of quantification (LOQ) of the analytes ranged 0.1-0.3 ng/mL and 0.4-1.0 ng/mL, respectively. The recovery rates with low, intermediate and high spiking levels were calculated as 95.5%-105.4%, 98.2%-114.0% and 92.2%-108.9%, respectively. Acceptable within-laboratory reproducibility (RSD<7.0%) substantially supported the use of current method for robust analysis. Rapid pretreatment procedures and short run time (8 min per sample) ensured good efficiency of metabolism profiling, indicating a wide application for investigating short-term internal exposure of dietary acrylamide. Our proposed UHPLC-MS/MS method was successfully applied to the toxicokinetic study of acrylamide in rats. Meanwhile, results of human urine analysis indicated that the levels of N-acetyl-S-(2-carbamoylethyl)-L-cysteine-sulfoxide (AAMA-sul), which did not appear in the mercapturic acid metabolites in rodents, were more than the sum of GAMA and N-acetyl-S-(1-carbamoyl-2-hydroxyethyl)-L-cysteine (iso-GAMA). Thus, AAMA-sul may alternatively become a specific biomarker for investigating the acrylamide exposure in humans. Current proposed method provides a substantial methodology support for comprehensive profiling of

  2. Probing Isotope Effects in Chemical Reactions Using Single Ions

    SciTech Connect

    Staanum, Peter F.; Hoejbjerre, Klaus; Drewsen, Michael; Wester, Roland

    2008-06-20

    Isotope effects in reactions between Mg{sup +} in the 3p {sup 2}P{sub 3/2} excited state and molecular hydrogen at thermal energies are studied through single reaction events. From only {approx}250 reactions with HD, the branching ratio between formation of MgD{sup +} and MgH{sup +} is found to be larger than 5. From an additional 65 reactions with H{sub 2} and D{sub 2} we find that the overall fragmentation probability of the intermediate MgH{sub 2}{sup +}, MgHD{sup +}, or MgD{sub 2}{sup +} complexes is the same. Our study shows that few single ion reactions can provide quantitative information on ion-neutral reactions. Hence, the method is well suited for reaction studies involving rare species, e.g., rare isotopes or short-lived unstable elements.

  3. Probing Isotope Effects in Chemical Reactions Using Single Ions

    NASA Astrophysics Data System (ADS)

    Staanum, Peter F.; Højbjerre, Klaus; Wester, Roland; Drewsen, Michael

    2008-06-01

    Isotope effects in reactions between Mg+ in the 3p P3/22 excited state and molecular hydrogen at thermal energies are studied through single reaction events. From only ˜250 reactions with HD, the branching ratio between formation of MgD+ and MgH+ is found to be larger than 5. From an additional 65 reactions with H2 and D2 we find that the overall fragmentation probability of the intermediate MgH2+, MgHD+, or MgD2+ complexes is the same. Our study shows that few single ion reactions can provide quantitative information on ion-neutral reactions. Hence, the method is well suited for reaction studies involving rare species, e.g., rare isotopes or short-lived unstable elements.

  4. Online Catalog of Isotope Products from DOE's National Isotope Development Center

    DOE Data Explorer

    The National Isotope Development Center (NIDC) interfaces with the User Community and manages the coordination of isotope production across the facilities and business operations involved in the production, sale, and distribution of isotopes. A virtual center, the NIDC is funded by the Isotope Development and Production for Research and Applications (IDPRA) subprogram of the Office of Nuclear Physics in the U.S. Department of Energy Office of Science. The Isotope subprogram supports the production, and the development of production techniques of radioactive and stable isotopes that are in short supply for research and applications. Isotopes are high-priority commodities of strategic importance for the Nation and are essential for energy, medical, and national security applications and for basic research; a goal of the program is to make critical isotopes more readily available to meet domestic U.S. needs. This subprogram is steward of the Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL), the Brookhaven Linear Isotope Producer (BLIP) facility at BNL, and hot cell facilities for processing isotopes at ORNL, BNL and LANL. The subprogram also coordinates and supports isotope production at a suite of university, national laboratory, and commercial accelerator and reactor facilities throughout the Nation to promote a reliable supply of domestic isotopes. The National Isotope Development Center (NIDC) at ORNL coordinates isotope production across the many facilities and manages the business operations of the sale and distribution of isotopes.

  5. Isotope separation

    DOEpatents

    Bartlett, Rodney J.; Morrey, John R.

    1978-01-01

    A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated.

  6. Rhenium-osmium isotope systematics of Group 2A and Group 4A iron meteorites

    NASA Technical Reports Server (NTRS)

    Creaser, R. A.; Papanastassiou, D. A.; Wasserburg, G. J.

    1993-01-01

    We are investigating the Re-Os isotope systematics of two groups of magmatic iron meteorites (2A, 4A) in an attempt to establish precise 'total rock' isochrons by the Re-Os system. The Re-187/Os-187 isotope system is recognized as a method by which the ages of iron meteorites can be directly determined and that can provide information on the timing of FeNi segregation and core formation in planetesimals. The Re-Os isotope system permits the direct absolute dating of the metal phase in iron meteorites. Indirect dating of iron meteorites has been achieved in the past through the Rb-Sr, K-Ar, and most recently, Sm-Nd for silicate inclusions, where present. Relative dating has been obtained directly by extensive studies of the short-lived system Pd-107/Ag-107 for the metal and sulfide phases and indirectly using I-129/Xe-129 in silicate and sulfide inclusions.

  7. Zn isotope fractionation during adsorption on birnessite

    NASA Astrophysics Data System (ADS)

    Bryan, A. L.; Dong, S.; Wasylenki, L. E.

    2013-12-01

    ) reported a mixture of tetrahedrally and octahedrally coordinated Zn sorbed on Mn oxides. In general, a species with lower coordination number favors heavier isotopes (Schauble, 2004). The potential explanations for the discrepancy between our results and our expectations include (1) a short-lived kinetic isotope effect favors sorption of light Zn in our short experiments, but will reverse on long time scales, (2) there are structural differences between our synthetic birnessite and Mn oxides previously studied, (3) our experiments are conducted at low ionic strength, and a change in Zn speciation at high ionic strength may lead to different isotope behavior. Our subsequent work will evaluate these possible explanations. Manceau et al. (2002). GCA 66, 2639-2663. Maréchal et al. (2000). G3 1, 1015. Schauble (2004). RiMG 55, 65-112.

  8. LU-HF Age and Isotope Systematics of ALH84001

    NASA Technical Reports Server (NTRS)

    Righter, M.; Lapen, T. J.; Brandon, A. D.; Beard, B. L.; Shafer, J. T.; Peslier, A. H.

    2009-01-01

    Allan Hills (ALH) 84001 is an orthopyroxenite that is unique among the Martian meteorites in having the oldest inferred crystallization age (approx..4.5 to 4.0 Gyr) [e.g., 1-6 and references therein 7]. Its ancient origin makes this stone a critical constraint on early history of Mars, in particular the evolution of different planetary crust and mantle reservoirs. However, because there is significant variability in reported crystallization ages, determination of initial isotope compositions is imprecise making assessment of planetary reservoirs difficult. Here we report a new Lu-Hf mineral isochron age, initial Hf-176/Hf-177 isotope composition, and inferred Martian mantle source compositions for ALH84001 that place constraints on longlived source reservoirs for the enriched shergottite suite of Martian meteorites including Shergotty, Zagami, NWA4468, NWA856, RBT04262, LAR06319, and Los Angeles. Sm-Nd isotope analyses are under way for the same mineral aliquots analyzed for Lu-Hf. The Lu-Hf system was utilized because Lu and Hf are both lithophile and refractory and are not easily redistributed during short-lived thermal pulses associated with shock metamorphism. Moreover, chromite has relatively modest Hf concentrations with very low Lu/Hf ratios [9] yielding tight constraints on initial Hf-176/Hf-177 isotope compositions

  9. Ab Initio Nuclear Structure and Reaction Calculations for Rare Isotopes

    SciTech Connect

    Draayer, Jerry P.

    2014-09-28

    We have developed a novel ab initio symmetry-adapted no-core shell model (SA-NCSM), which has opened the intermediate-mass region for ab initio investigations, thereby providing an opportunity for first-principle symmetry-guided applications to nuclear structure and reactions for nuclear isotopes from the lightest p-shell systems to intermediate-mass nuclei. This includes short-lived proton-rich nuclei on the path of X-ray burst nucleosynthesis and rare neutron-rich isotopes to be produced by the Facility for Rare Isotope Beams (FRIB). We have provided ab initio descriptions of high accuracy for low-lying (including collectivity-driven) states of isotopes of Li, He, Be, C, O, Ne, Mg, Al, and Si, and studied related strong- and weak-interaction driven reactions that are important, in astrophysics, for further understanding stellar evolution, X-ray bursts and triggering of s, p, and rp processes, and in applied physics, for electron and neutrino-nucleus scattering experiments as well as for fusion ignition at the National Ignition Facility (NIF).

  10. More on Ru Endemic Isotope Anomalies in Meteorites

    NASA Technical Reports Server (NTRS)

    Papanastassiou, D. A.; Chen, J. H.; Wasserburg, G. J.

    2004-01-01

    We reported last year on endemic isotope anomalies for Ru in iron meteorites, pallasites, ordinary chondrites, and on a whole-rock sample of Allende. We have extended the Ru measurements to more meteorites, to refractory Ca-Al-rich inclusions (CAI) from Allende, and to a whole rock sample of Murchison (CM2). In a companion abstract we report on new measurements for the Mo isotopes, in some of the same samples. There has been a renewed interest in searching for isotope anomalies in this nuclide region, as Ru and Mo include many isotopes from r-, s-, and p-process nucleosynhesis. Furthermore, the Ru and Mo p-process isotopes show atypically high abundances, which have been hard to explain through the standard nucleosynthetic processes. Effects are possible in Ru-98 and Ru-99 from Tc-98 (with a poorly known t(sub 1/2)=4.2 to 10Ma) and from Tc-99 (t(sub 1/2)=0.21Ma). Natural Tc is now extinct on Earth due to the short half-lives, but may have been present in the early solar system. Both radiogenic and general isotope anomalies are important in understanding the processes for the formation of the early solar system. The current emphasis on Ru and Mo is also the result of the development of Negative-ion Thermal Ionization Mass Spectrometry and of Multiple-Collector, Inductively-Coupled-Mass-Spectrometry. We have also developed specific chemical siparation techniques for Ru, which eliminated mass interference effects.

  11. Charge radii of neon isotopes across the sd neutron shell

    SciTech Connect

    Marinova, K.; Geithner, W.; Kappertz, S.; Kloos, S.; Kotrotsios, G.; Neugart, R.; Wilbert, S.; Kowalska, M.; Keim, M.; Blaum, K.; Lievens, P.; Simon, H.

    2011-09-15

    We report on the changes in mean square charge radii of unstable neon nuclei relative to the stable {sup 20}Ne, based on the measurement of optical isotope shifts. The studies were carried out using collinear laser spectroscopy on a fast beam of neutral neon atoms. High sensitivity on short-lived isotopes was achieved thanks to nonoptical detection based on optical pumping and state-selective collisional ionization, which was complemented by an accurate determination of the beam kinetic energy. The new results provide information on the structural changes in the sequence of neon isotopes all across the neutron sd shell, ranging from the proton drip line nucleus and halo candidate {sup 17}Ne up to the neutron-rich {sup 28}Ne in the vicinity of the ''island of inversion.'' Within this range the charge radius is smallest for {sup 24}Ne with N=14 corresponding to the closure of the neutron d{sub 5/2} shell, while it increases toward both neutron shell closures, N=8 and N=20. The general trend of the charge radii correlates well with the deformation effects which are known to be large for several neon isotopes. In the neutron-deficient isotopes, structural changes arise from the onset of proton-halo formation for {sup 17}Ne, shell closure in {sup 18}Ne, and clustering effects in {sup 20,21}Ne. On the neutron-rich side the transition to the island of inversion plays an important role, with the radii in the upper part of the sd shell confirming the weakening of the N=20 magic number. The results add new information to the radii systematics of light nuclei where data are scarce because of the small contribution of nuclear-size effects to the isotope shifts which are dominated by the finite-mass effect.

  12. Short stature

    MedlinePlus

    Idiopathic short stature; Non-growth hormone deficient short stature ... Turner syndrome Williams syndrome Other reasons include: Growth hormone deficiency Infections of the developing baby before birth ...

  13. Molybdenum Isotopes and Soil Processes

    NASA Astrophysics Data System (ADS)

    Siebert, C.; Pett-Ridge, J. C.; Halliday, A. N.; Burton, K. W.

    2011-12-01

    The oxygenation state of Earth's oceans is a driver of evolution and extinction events as well as climate change. In recent years stable isotope fractionation of redox sensitive elements such as molybdenum (Mo) have been used as quantitative tracers of past redox-conditions in a number of marine environments. However, little is known about the processes controlling the Mo isotope compositions of the riverine inputs to the oceans and their short- and long-term variations. Several recent studies [Archer & Vance, 2008; Pearce et al., 2010] have shown that many river waters have heavy Mo isotope compositions. In some terrestrial weathering environments dissolved Mo isotope compositions in rivers are controlled by the catchment lithology [Neubert et al., 2011]. However, many rivers show fractionation of Mo isotopes relative to their catchment lithology. Possible mechanisms causing this fractionation are chemical weathering and pedogenic processes. This study has investigated the behavior of Mo isotopes during weathering of basalt under different conditions. Results from oxic to reducing soil profiles in Hawaii show that redox conditions during soil formation can control Mo isotope compositions in soils. Reducing soil profiles have light isotope compositions whereas oxidizing profiles are heavy. This general isotope behavior is confirmed by results from soil profiles from Iceland. Here reducing layers within the profiles show marked negative isotope excursions. In oxic profiles a surprisingly strong interaction of Mo with organic matter can be observed producing significant Mo isotope fractionation. This behavior might explain long term retention of Mo in soils besides its high mobility in molybdate form. Mo associated with organic matter is bioavailable and essential for processes like nitrogen fixation. In addition, we observe that fractionation relative to the source rock is dependent on the degree of weathering, i.e. relatively un-weathered profiles do not show

  14. Transuranium isotopes

    SciTech Connect

    Hoffman, D.C.

    1985-12-01

    The needs of the research community for the production of transuranium isotopes, the quantities required, the continuity of production desired, and what a new steady state neutron source would have to provide to satisfy these needs are discussed. Examples of past frontier research which need these isotopes as well as an outline of the proposed Large Einsteinium Activation Program, LEAP, which requires roughly ten times the current production of /sup 254/Es are given. 15 refs., 5 figs., 4 tabs.

  15. Isotopic Paleoclimatology

    NASA Astrophysics Data System (ADS)

    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. Isotopic chirality

    SciTech Connect

    Floss, H.G.

    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.

  17. Assisted Living

    MedlinePlus

    ... but they don't need full-time nursing care. Some assisted living facilities are part of retirement ... change. Assisted living costs less than nursing home care. It is still fairly expensive. Older people or ...

  18. Manganese chromium isotope systematics of carbonaceous chondrites

    NASA Astrophysics Data System (ADS)

    Shukolyukov, A.; Lugmair, G. W.

    2006-10-01

    In this article we present the results of Cr isotope investigations of different types of carbonaceous chondrites and of the pallasite Eagle Station. The 53Cr/ 52Cr ratios in the bulk samples of carbonaceous chondrites are correlated with 55Mn/ 52Cr ratios. The slope of the correlation line yields a 53Mn/ 55Mn ratio of (8.5 ± 1.5) × 10 - 6 at the time of Mn/Cr fractionation. Mapping this ratio onto an absolute time scale yields a time for this event of 4568.1 + 0.8/- 1.1 Ma ago. This time is very similar to the formation age of Efremovka CAIs of 4567.2 ± 0.6 Ma [Y. Amelin, A. N. Krot, I. D. Hutcheon, A. A. Ulyanov, Lead isotopic ages of chondrules and calcium-aluminum-rich inclusions, Science 297 (2002) 1678-1683], to a time of the chondrule formation of 4568 ± 1 Ma ago [L.E. Nyquist, D. Lindstrom, D. Mittlefehldt, C.-Y. Shih, H. Wiesmann, S. Wentworth, R. Martinez, Manganese-chromium formation intervals for chondrules from the Bishunpur and Chainpur meteorites, Meteorit. Planet. Sci. 36 (2001) 911-938], which, most likely, constrains early global high-temperature Mn/Cr fractionation in a nebular setting. The bulk samples of carbonaceous chondrites exhibit clear 54Cr excesses ( 54Cr *) that are correlated with the 53Cr excesses ( 53Cr *) and also with Mn/Cr ratios. One possible explanation of this correlation is that 54Cr * is also radiogenic, like 53Cr *, and was formed by the decay of the short-lived parent radionuclide 54Mn. The very short half-life of 54Mn of 312 days would require that both short-lived radionuclides 53Mn and 54Mn were generated locally in spallation reactions during the early period of an active sun. The alternative and possibly more plausible explanation is the heterogeneous addition of presolar material. The presolar component, enriched in 54Cr, is mostly contained in the matrix of carbonaceous chondrites. The relative amount of matrix decreases in the sequence CI > CM > CO,CV. A large proportion of Mn is associated with the matrix while

  19. Calculation of the fission-fragment yields of the pre-actinide nuclei by the example of the natPb isotopes

    NASA Astrophysics Data System (ADS)

    Maslyuk, V. T.; Parlag, O. A.; Lendyel, O. I.; Marynets, T. I.; Romanyuk, M. I.; Shevchenko, O. S.; Ranyuk, Ju. Ju.; Dovbnya, A. M.

    2016-11-01

    The calculations of the fission-fragment yields (mass and charge spectra) carried out within the frameworks of the proposed statistical method for the pre-actinide nuclei by the example of natPb (20 isotopes) are presented. The role of neutron shells with N = 50 and N = 82 in realizing the single- and double-humped shape of the fission-fragment yields, respectively, for the neutron-deficit and neutron-excess Pb isotopes has been investigated. An explanation of the experimental results on the natPb fission was performed taking into account transformations to the ensemble of the long- and short-lived nuclear fragments.

  20. Superheavies: Short-Term Experiments and Far-Reaching Designs

    NASA Astrophysics Data System (ADS)

    Zagrebaev, V. I.; Karpov, A. V.; Mishustin, I. N.; Greiner, Walter

    Low values of the fusion cross sections and very short half-lives of nuclei with Z>120 put obstacles in synthesis of new elements. However the fusion reactions of medium mass projectiles with different actinide targets still can be used for the production of the not-yet-synthesized SH nuclei. The gap of unknown SH nuclei, located between the isotopes which were produced earlier in the cold and hot fusion reactions, could be filled in fusion reactions of ^{48}Ca with available lighter isotopes of Pu, Am, and Cm. Cross sections for the production of these nuclei are predicted to be rather large, and the corresponding experiments can be easily performed at existing facilities. The use of heavier actinide targets give us a chance to produce more neutron enriched SH isotopes. Moreover, for the first time, a narrow pathway is found to the middle of the island of stability owing to possible β ^+ decay of SH isotopes which can be formed in ordinary fusion reactions of stable nuclei. Multi-nucleon transfer processes at near barrier collisions of heavy (and very heavy, U-like) ions seem to be quite realistic reaction mechanism allowing us to produce new neutron enriched heavy nuclei located in the unexplored upper part of the nuclear map. Neutron capture reactions can be also used for the production of the long-living neutron rich SH nuclei. Strong neutron fluxes might be provided by pulsed nuclear reactors and by nuclear explosions in laboratory conditions and by supernova explosions in nature. All these possibilities are discussed in the chapter.

  1. Carbonate clumped isotope bond reordering and geospeedometry

    NASA Astrophysics Data System (ADS)

    Passey, Benjamin H.; Henkes, Gregory A.

    2012-10-01

    short-lived hydrothermal event (Bristow et al., 2011, Nature v. 474, p. 68-71). Most of the uncertainty in these estimates relates to uncertainty in Arrhenius parameters for different calcites. Thus, while the carbonate clumped isotope geospeedometer shows promise for recording cooling rates in settings and lithologies where other geospeedometers may not be applicable, the uncertainty in cooling rate will be large without independent knowledge of the reordering kinetics of each study material. Thus the full potential of the method will only be realized if reordering kinetics can be accurately determined for each study material, or predicted on the basis of mineral composition, texture, or other observable parameters.

  2. IRON-60 HETEROGENEITY AND INCOMPLETE ISOTOPE MIXING IN THE EARLY SOLAR SYSTEM

    SciTech Connect

    Quitte, Ghylaine; Markowski, Agnes; Latkoczy, Christopher; Gabriel, Aron; Pack, Andreas

    2010-09-10

    Short-lived radionuclides (e.g., {sup 26}Al, {sup 53}Mn, {sup 60}Fe, {sup 182}Hf) are widely used to refine the chronology of the early solar system. They provide chronological information, however, only if they were homogeneously distributed in the source region of the objects under scrutiny at the time of their formation. With the high level of precision now achieved on isotopic measurements, very short time intervals can in principle be resolved and a precise evaluation of the initial homogeneity degree becomes increasingly crucial. High-precision nickel isotope data for differentiated meteorites (angrites, ureilites) and chondritic (CB) components allow us to test the initial distribution of radioactive {sup 60}Fe and stable Ni isotopes. Although these meteorites appear to have formed nearly contemporaneously, they yield variable initial {sup 60}Fe/{sup 56}Fe ratios. Besides, the CB metal nodules and ureilite silicates show nucleosynthetic anomalies. The new data presented here do not confirm the recently inferred late injection of {sup 60}Fe into the protoplanetary disk. Instead, live {sup 60}Fe was present, but heterogeneously distributed, from the start of the solar system, revealing an incomplete mixing of material from various nucleosynthetic sources and restricting the use of the {sup 60}Fe-{sup 60}Ni system as a chronometer.

  3. Calcium isotope analysis by mass spectrometry.

    PubMed

    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

  4. ISOTOPE SEPARATORS

    DOEpatents

    Bacon, C.G.

    1958-08-26

    An improvement is presented in the structure of an isotope separation apparatus and, in particular, is concerned with a magnetically operated shutter associated with a window which is provided for the purpose of enabling the operator to view the processes going on within the interior of the apparatus. The shutier is mounted to close under the force of gravity in the absence of any other force. By closing an electrical circuit to a coil mouated on the shutter the magnetic field of the isotope separating apparatus coacts with the magnetic field of the coil to force the shutter to the open position.

  5. Isotopic Randomness and Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Berezin, Alexander A.

    2005-03-01

    Isotopic disorder in crystals can lead to suppression of thermal conductivity, mobility variations and (weak) Anderson localization on isotopic fluctuations. The latter (AAB, J.ChemPhys.1984) is akin to polaron effect (self-localization due polarization). Possibility of isotopic patterning (IP) increases near melting point (thermally activated isotopic hopping swaps). Crystal near melting threshold become “informationally sensitive” as if its IP is operated by some external Maxwell’s Demon, MD (AAB, URAM J, 2002). At this state short range (e.g. electrostatic inverse square) forces evolve into long-range interactions (due to divergence of order parameter) and information sensitivity can be further amplified by (say) a single fast electron (e.g. beta-particle from decay of 14-C or other radioactive isotope) which may result in cascade of impact ionization events and (short time-scale) enhancement of screening by impact-generated non-equilibrium (non-thermal) electrons. In this state informationally driven (MD-controlled) IP (Eccles effect) can result in decrease of positional entropy signifying emergence of physical complexity out of pure information, similar to peculiar “jinni effect” on closed time loops in relativistic cosmology (R.J.Gott, 2001) or Wheeler’s “it from bit” metaphor. By selecting special IP, MD modifies ergodicity principle in favor of info rich states.

  6. Assisted Living

    MedlinePlus

    ... it, too. Back to top What is the Cost for Assisted Living? Although assisted living costs less than nursing home care, it is still ... of services an older person chooses, the price costs can range from less than $25,000 a ...

  7. Zinc isotope fractionation during adsorption onto Mn oxyhydroxide at low and high ionic strength

    NASA Astrophysics Data System (ADS)

    Bryan, Allison L.; Dong, Shuofei; Wilkes, Elise B.; Wasylenki, Laura E.

    2015-05-01

    Marine ferromanganese sediments represent one of the largest sinks from global seawater for Zn, a critical trace metal nutrient. These sediments are variably enriched in heavier isotopes of Zn relative to deep seawater, and some are among the heaviest natural samples analyzed to date. New experimental results demonstrate that adsorption of Zn to poorly crystalline Mn oxyhydroxide results in preferential association of heavier isotopes with the sorbent phase. At low ionic strength our experimental system displayed a short-lived kinetic isotope effect, with light isotopes adsorbed to birnessite (Δ66/64Znadsorbed-dissolved ∼ -0.2‰). After 100 h the sense of fractionation was opposite, such that heavier isotopes were preferentially adsorbed at steady state, but the magnitude of Δ66/64Znadsorbed-dissolved was indistinguishable from zero (+0.05 ± 0.08‰). At high ionic strength, we observed preferential sorption of heavy isotopes, with a strong negative correlation between Δ66/64Znadsorbed-dissolved and the percentage of Zn on the birnessite. Values of Δ66/64Znadsorbed-dissolved ranged from nearly +3‰ at low surface loading to +0.16‰ at high surface loading. Based on previous EXAFS work we infer that Zn adsorbs first as tetrahedral, inner-sphere complexes at low surface loading, with preferential incorporation of heavier isotopes relative to the octahedral Zn species predominating in solution. As surface loading increases, so does the proportion of Zn adsorbing as octahedral complexes, thus diminishing the magnitude of fractionation between the dissolved and adsorbed pools of Zn. The magnitude of fractionation at high ionic strength is also governed by aqueous speciation of Zn in synthetic seawater; a substantial fraction of Zn ions reside in chloro complexes, which preferentially incorporate light Zn isotopes, and this drives the adsorbed pool to be heavier relative to the bulk solution than it was at low ionic strength. Our results explain the observation

  8. Isotope specific resolution recovery image reconstruction in high resolution PET imaging

    SciTech Connect

    Kotasidis, Fotis A.; Angelis, Georgios I.; Anton-Rodriguez, Jose; Matthews, Julian C.; Reader, Andrew J.; Zaidi, Habib

    2014-05-15

    Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

  9. Compelling Research Opportunities using Isotopes

    SciTech Connect

    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) medicine

  10. Determination of the cross section for (n,p) reaction with producing short-lived nuclei on the 162,163Dy isotopes at 13.5 and 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Luo, Junhua; Feng, Zhifu; An, Li; Jiang, Li; He, Long

    2016-06-01

    Activation cross-sections for the 162Dy(n,p)162Tb and 163Dy(n,p)163Tb reactions have been measured by means of the activation technique and a coaxial HPGe γ-ray detector at 13.5 and 14.8 MeV. The fast neutrons were produced via the 3H(d,n)4He reaction on Pd-300 neutron generator. The natural high-purity Dy2O3 powder was used as target material. Theoretical excitation functions were calculated using the nuclear-reaction codes EMPIRE-3.2 Malta and TALYS-1.6 with default parameters, at neutron energies varying from the reaction threshold to 20 MeV. The results were also discussed and compared with some corresponding values found in the literature, with the comprehensive evaluation data in ENDF/B-VII.1 and JENDF-4.0 libraries, and with the estimates obtained from a published empirical formula based on the statistical model with Q-value dependence and odd-even effects taken into consideration.

  11. The Need for a Neutron Source at the Rare Isotope Accelerator

    SciTech Connect

    Ahle, L E; Rusnak, B; Roberts, K E; Roeben, M D; Hausmann, M; Reifarth, R; Vieira, D

    2005-05-13

    An intense neutron source facility with radiochemical processing capability is necessary at the Rare Isotope Accelerator to fully realize its potential benefit to stockpile stewardship and astrophysics. While many of the important physics missions of RIA can be addressed with radioactive ion beams, direct neutron cross-section measurements of interest to stockpile stewardship and astrophysics cannot because one cannot make a neutron target. Thus, one must collect a sufficient amount of the appropriate short-lived isotope, quickly chemically process the material into a target, and promptly radiate the sample with an intense ''beam'' of neutrons. The unprecedented production rates expected at RIA enables many of these direct neutron cross-section measurements, but only if the proper infrastructure is in place. This document not only describes the major piece of this required infrastructure, a neutron source facility with radiochemical processing capabilities, but also the motivation for measuring such direct neutron cross-sections.

  12. Assisted Living

    MedlinePlus

    ... Recreational activities Security Transportation How to Choose a Facility A good match between a facility and a resident's needs depends as much on the philosophy and services of the assisted living facility as it does on the quality of care. ...

  13. Bachelor Living

    ERIC Educational Resources Information Center

    Germer, Sondra

    1974-01-01

    Male high school students in a Bachelor Living Class observed methods of child care including bottle feeding, spoon feeding, changing diapers, and method of holding. The purpose was for the students to grasp a better understanding of child development. (EK)

  14. Healthy Living

    MedlinePlus

    ... Environment Kids Health Kids Environment Kids Health Topics Environment & Health Healthy Living Pollution Reduce, Reuse, Recycle Science – How It Works The Natural World Games Brainteasers Puzzles Riddles Songs Activities Be ...

  15. Living Laboratories

    ERIC Educational Resources Information Center

    Mules, B. R.

    1976-01-01

    Presented is a review of various methods of keeping live animals, including scorpions, spiders, crabs, crayfish, shrimp, ants, fish, mice, and birds, as well as plants as a school science project/display. (SL)

  16. Assisted Living

    MedlinePlus

    ... premises. Adult foster care has the advantages of maintaining frail older adults in a more home-like ... pay to live in these communities, though some facilities have beds for skilled care that are funded ...

  17. A multi-model intercomparison of halogenated very short-lived substances (TransCom-VSLS): linking oceanic emissions and tropospheric transport for a reconciled estimate of the stratospheric source gas injection of bromine

    NASA Astrophysics Data System (ADS)

    Hossaini, R.; Patra, P. K.; Leeson, A. A.; Krysztofiak, G.; Abraham, N. L.; Andrews, S. J.; Archibald, A. T.; Aschmann, J.; Atlas, E. L.; Belikov, D. A.; Bönisch, H.; Carpenter, L. J.; Dhomse, S.; Dorf, M.; Engel, A.; Feng, W.; Fuhlbrügge, S.; Griffiths, P. T.; Harris, N. R. P.; Hommel, R.; Keber, T.; Krüger, K.; Lennartz, S. T.; Maksyutov, S.; Mantle, H.; Mills, G. P.; Miller, B.; Montzka, S. A.; Moore, F.; Navarro, M. A.; Oram, D. E.; Pfeilsticker, K.; Pyle, J. A.; Quack, B.; Robinson, A. D.; Saikawa, E.; Saiz-Lopez, A.; Sala, S.; Sinnhuber, B.-M.; Taguchi, S.; Tegtmeier, S.; Lidster, R. T.; Wilson, C.; Ziska, F.

    2016-07-01

    The first concerted multi-model intercomparison of halogenated very short-lived substances (VSLS) has been performed, within the framework of the ongoing Atmospheric Tracer Transport Model Intercomparison Project (TransCom). Eleven global models or model variants participated (nine chemical transport models and two chemistry-climate models) by simulating the major natural bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2), over a 20-year period (1993-2012). Except for three model simulations, all others were driven offline by (or nudged to) reanalysed meteorology. The overarching goal of TransCom-VSLS was to provide a reconciled model estimate of the stratospheric source gas injection (SGI) of bromine from these gases, to constrain the current measurement-derived range, and to investigate inter-model differences due to emissions and transport processes. Models ran with standardised idealised chemistry, to isolate differences due to transport, and we investigated the sensitivity of results to a range of VSLS emission inventories. Models were tested in their ability to reproduce the observed seasonal and spatial distribution of VSLS at the surface, using measurements from NOAA's long-term global monitoring network, and in the tropical troposphere, using recent aircraft measurements - including high-altitude observations from the NASA Global Hawk platform. The models generally capture the observed seasonal cycle of surface CHBr3 and CH2Br2 well, with a strong model-measurement correlation (r ≥ 0.7) at most sites. In a given model, the absolute model-measurement agreement at the surface is highly sensitive to the choice of emissions. Large inter-model differences are apparent when using the same emission inventory, highlighting the challenges faced in evaluating such inventories at the global scale. Across the ensemble, most consistency is found within the tropics where most of the models (8 out of 11) achieve best agreement to surface CHBr3 observations

  18. Measurement of picosecond lifetimes in neutron-rich Xe isotopes

    NASA Astrophysics Data System (ADS)

    Ilieva, S.; Kröll, Th.; Régis, J.-M.; Saed-Samii, N.; Blanc, A.; Bruce, A. M.; Fraile, L. M.; de France, G.; Hartig, A.-L.; Henrich, C.; Ignatov, A.; Jentschel, M.; Jolie, J.; Korten, W.; Köster, U.; Lalkovski, S.; Lozeva, R.; Mach, H.; Mǎrginean, N.; Mutti, P.; Paziy, V.; Regan, P. H.; Simpson, G. S.; Soldner, T.; Thürauf, M.; Ur, C. A.; Urban, W.; Warr, N.

    2016-09-01

    Background: Lifetimes of nuclear excited states in fission fragments have been studied in the past following isotope separation, thus giving access mainly to the fragments' daughters and only to long-lived isomeric states in the primary fragments. For the first time now, short-lived excited states in the primary fragments, produced in neutron-induced prompt fission of 235U and 241Pu, were studied within the EXILL&FATIMA campaign at the intense neutron-beam facility of the Institute Laue-Langevin in Grenoble. Purpose: We aim to investigate the quadrupole collective properties of neutron-rich even-even 138,140,142Xe isotopes lying between the double shell closure N =82 and Z =50 and a deformed region with octupole collectivity. Method: The γ rays emitted from the excited fragments were detected with a mixed array consisting of 8 HPGe EXOGAM Clover detectors (EXILL) and 16 LaBr3(Ce) fast scintillators (FATIMA). The detector system has the unique ability to select the interesting fragment making use of the high resolution of the HPGe detectors and determine subnanosecond lifetimes using the fast scintillators. For the analysis the generalized centroid difference method was used. Results: We show that quadrupole collectivity increases smoothly with increasing neutron number above the closed N =82 neutron shell. Our measurements are complemented by state-of-the-art theory calculations based on shell-model descriptions. Conclusions: The observed smooth increase in quadrupole collectivity is similar to the evolution seen in the measured masses of the xenon isotopic chain and is well reproduced by theory. This behavior is in contrast to higher Z even-even nuclei where abrupt change in deformation occurs around N =90 .

  19. Radium isotopes in Cayuga Lake, New York: Indicators of inflow and mixing processes

    USGS Publications Warehouse

    Kraemer, T.F.

    2005-01-01

    Naturally occurring radium isotopes (223Ra, 224Ra, 226Ra, and 228Ra) were measured in lake and tributary water of Cayuga Lake, New York, during the course of a vernal inflow event in the spring of 2001. A large influx of groundwater, probably from a carbonate aquifer, entered the lake at its extreme southern end early in the vernal inflow event and spread northward, covering an extensive part of the southern end of the lake. The low 228Ra/226Ra activity ratio of this water mass, compared with bulk lake water, allowed its identification through time. Estimates of mixing with bulk lake water were calculated from changes in the 226Ra content. Groundwater inflow to the lake around the delta of a major tributary was detected on the basis of 223Ra and 224Ra activity of lake and tributary water. Inflow of a water mass to the surface of the lake was also detected using 223Ra and 224Ra activity. The integrity of this water mass was monitored using short-lived radium isotopes. Suspended sediment in the lake water is a source of the short-lived radium isotopes 223Ra (???2 ?? 10 -4 dpm L-1) and 224Ra (???3 ?? 10 -3 dpm L-1), but bottom sediments are a more significant source of 228Ra. Radium isotopes can be valuable new tools in limnological investigations, allowing detection and monitoring of events and processes such as water inflow and mixing, determining sources of inflowing water, and monitoring introduced water masses as they move within the lake.

  20. Isotopic generator for bismuth-212 and lead-212 from radium

    DOEpatents

    Atcher, Robert W.; Friedman, Arnold M.; Hines, John

    1987-01-01

    A method and apparatus for providing radionuclides of bismuth-212 and lead-212. Thorium-228 and carrier solution starting material is input to a radiologically contained portion of an isotopic generator system, and radium-224 is separated from thorium-228 which is retained by a strongly basic anion exchange column. The separated radium-224 is transferred to an accessible, strongly acidic cationic exchange column. The cationic column retains the radium-224, and natural radioactive decay generates bismuth-212 and lead-212. The cationic exchange column can also be separated from the contained portion of the system and utilized without the extraordinary safety measures necessary in the contained portion. Furthermore, the cationic exchange column provides over a relatively long time period the short lived lead-212 and bismuth-212 radionuclides which are useful for a variety of medical therapies.

  1. Incorporation of stable and radioactive isotopes via organoborane chemistry

    SciTech Connect

    Kabalka, G.W.

    1984-06-01

    An organic synthesis involving the use of organoboranes rather than the traditional substitution reactions and Grignard reagents for the rapid preparation of physiologically active materials labelled with short-lived isotopes is discussed in detail. The iodination reaction for incorporating I-123 or I-125 into compounds was found to proceed via an electrophilic attack by the iodine molecule on the electron-rich borax complex, did not require the presence of strong base, and was complete in 60 sec. The procedure also uses radiolabeled NaI rather than the more unstable iodine monochloride usually used. A similar procedure was developed for labelling compounds with Br-77. Other direct one-pot syntheses are described for incorporation of O-17, N-13, N-15, C-11, and C-13 into compounds very rapidly.

  2. Lead and strontium isotopic evidence for crustal interaction and compositional zonation in the source regions of Pleistocene basaltic and rhyolitic magmas of the Coso volcanic field, California

    USGS Publications Warehouse

    Bacon, C.R.; Kurasawa, H.; Delevaux, M.H.; Kistler, R.W.; Doe, B.R.

    1984-01-01

    The isotopic compositions of Pb and Sr in Pleistocene basalt, high-silica rhyolite, and andesitic inclusions in rhyolite of the Coso volcanic field indicate that these rocks were derived from different levels of compositionally zoned magmatic systems. The 2 earliest rhyolites probably were tapped from short-lived silicic reservoirs, in contrast to the other 36 rhyolite domes and lava flows which the isotopic data suggest may have been leaked from the top of a single, long-lived magmatic system. Most Coso basalts show isotopic, geochemical, and mineralogic evidence of interaction with crustal rocks, but one analyzed flow has isotopic ratios that may represent mantle values (87Sr/86Sr=0.7036,206Pb/204Pb=19.05,207Pb/204Pb=15.62,208Pb/204Pb= 38.63). The (initial) isotopic composition of typical rhyolite (87Sr/86Sr=0.7053,206Pb/204Pb=19.29,207Pb/204Pb= 15.68,208Pb/204Pb=39.00) is representative of the middle or upper crust. Andesitic inclusions in the rhyolites are evidently samples of hybrid magmas from the silicic/mafic interface in vertically zoned magma reservoirs. Silicic end-member compositions inferred for these mixed magmas, however, are not those of erupted rhyolite but reflect the zonation within the silicic part of the magma reservoir. The compositional contrast at the interface between mafic and silicic parts of these systems apparently was greater for the earlier, smaller reservoirs. ?? 1984 Springer-Verlag.

  3. Multiple linear regression for isotopic measurements

    NASA Astrophysics Data System (ADS)

    Garcia Alonso, J. I.

    2012-04-01

    There are two typical applications of isotopic measurements: the detection of natural variations in isotopic systems and the detection man-made variations using enriched isotopes as indicators. For both type of measurements accurate and precise isotope ratio measurements are required. For the so-called non-traditional stable isotopes, multicollector ICP-MS instruments are usually applied. In many cases, chemical separation procedures are required before accurate isotope measurements can be performed. The off-line separation of Rb and Sr or Nd and Sm is the classical procedure employed to eliminate isobaric interferences before multicollector ICP-MS measurement of Sr and Nd