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Sample records for short lived isotopes

  1. Beta Decay Studies of Short Lived Barium Isotopes

    NASA Astrophysics Data System (ADS)

    Bendall, Charles Skipwith

    The half-lives and relative intensities of several short lived neutron rich isotopes, with atomic numbers between 54 and 57, produced in the spontaneous fission of californium-252 were determined. This was accomplished from the study of the time variation of the K X-ray yields of these isotopes. A transport system which allowed us to study isotopes with half-lives less than 10 seconds was developed. Mass assignments were made by comparing the experimental values of the half-lives with known values. A beta K X-ray coincidence technique was used to obtain the barium beta spectrum in coincidence with lanthanum K X -rays. A Kurie plot was performed on the spectrum to determine the beta groups. The probable origin of each beta group was determined through a comparison of the relative intensities of the isotopes and beta groups. Four beta groups probably from the decay of Ba-145 were revealed. The end point energies of these beta groups are 3870 (+OR-) 432 keV, 2772 (+OR-) 112 keV, 1894 (+OR-) 58 keV, and 746 (+OR-) 38 keV. The three lowest energy groups have not been observed before.

  2. Laser trapping of short-lived radioactive isotopes

    SciTech Connect

    Lu, Z.; Bowers, C.; Freedman, S.J.; Fujikawa, B.K.; Mortara, J.L.; Shang, S. ); Coulter, K.P.; Young, L. )

    1994-06-13

    We describe an experiment which demonstrates the feasibility of trapping significant quantities of short-lived radioactive atoms with laser light. A thermal beam of 22.5 sec half-life [sup 21]Na atoms was produced on-line at the LBL 88[prime][prime] Cyclotron. After decelerating the beam using a Zeeman-tuned slowing technique we stored about 4[times]10[sup 3] [sup 21]Na atoms in a magneto-optical trap. The number of trapped atoms is large enough to be used in experimental studies of the beta decay of [sup 21]Na. The basic method can be adapted for other rare isotopes.

  3. Emission Channeling with Short-Lived Isotopes (EC-SLI) at CERN's ISOLDE Facility

    NASA Astrophysics Data System (ADS)

    Wahl, U.; Correia, J. G.; Costa, A.; David-Bosne, E.; Pereira, L. M. C.; Amorim, L. M.; Augustyns, V.; Temst, K.; Vantomme, A.; da Silva, M. R.; Silva, D. J.; Araújo, J. P.; Miranda, P.; Bharuth-Ram, K.

    2015-11-01

    We give an overview on the historical development and current program for lattice location studies at CERN's ISOLDE facility, where the EC-SLI (Emission Channeling with Short-Lived Isotopes) collaboration maintains several setups for this type of experiments. We illustrate that the three most decisive factors for the success of the technique are access to facilities producing radioactive isotopes, position-sensitive detectors for the emitted decay particles, and reliable simulation codes which allow for quantitative analysis.

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

    NASA Astrophysics Data System (ADS)

    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.

    2015-12-01

    Two short-lived isotopes 221U and 222U were produced as evaporation residues in the fusion reaction 50Ti + 176Yb at the gas-filled recoil separator TASCA. An α decay with an energy of Eα=9.31 (5 ) MeV and half-life T1 /2=4.7 (7 ) μ s was attributed to 222U. The new isotope 221U was identified in α -decay chains starting with Eα=9.71 (5 ) MeV and T1 /2=0.66 (14 ) μ s 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.

  5. Separation efficiency of the MASHA facility for short-lived mercury isotopes

    NASA Astrophysics Data System (ADS)

    Rodin, A. M.; Belozerov, A. V.; Chernysheva, E. V.; Dmitriev, S. N.; Gulyaev, A. V.; Gulyaeva, A. V.; Itkis, M. G.; Kliman, J.; Kondratiev, N. A.; Krupa, L.; Novoselov, A. S.; Oganessian, Yu. Ts.; Podshibyakin, A. V.; Salamatin, V. S.; Siváček, I.; Stepantsov, S. V.; Vanin, D. V.; Vedeneev, V. Yu.; Yukhimchuk, S. A.; Granja, C.; Pospisil, S.

    2014-06-01

    The mass-separator MASHA built to identify Super Heavy Elements by their mass-to-charge ratios is described. The results of the off- and on-line measurements of its separation efficiency are presented. In the former case four calibrated leaks of noble gases were used. In the latter the efficiency was measured via 284 MeV Ar beam and with using the hot catcher. The ECR ion source was used in both cases. The -radioactive isotopes of mercury produced in the complete fusion reaction Ar+SmHg+xn were detected at the mass-separator focal plane. The half-lives and the separation efficiency for the short-lived mercury isotopes were measured. Potentialities of the MEDIPIX detector system have been demonstrated for future use at the mass-separator MASHA.

  6. 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

  7. 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.

  8. 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.

  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. 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.

  11. 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.

  12. Investigating carbon sources to the North Sea using short-lived radium isotope distributions

    NASA Astrophysics Data System (ADS)

    Burt, William; Thomas, Helmuth; Pätsch, Johannes

    2013-04-01

    Carbon cycling in the North Sea is affected by inputs of atmospheric CO2, as well as inputs of carbonate species (dissolved inorganic carbon (DIC) and alkalinity (AT)) from various sources including adjacent seas, the sediments lining the ocean floor and from land. While the atmospheric contribution is well understood, this study intends to identify the sedimentary and lateral additions of DIC and AT, and their contributions to the North Sea carbon budget. We propose to quantify these carbon fluxes by utilizing a radium (Ra) isotope tracer technique to first quantify diffusive inputs and Ra dispersion in the North Sea. During a Royal Netherlands Institute for Sea Research (NIOZ) cruise in summer, 2011, the Ra data set was collected 3-dimensionally in the water column, as well as within sediment cores, representing uniquely comprehensive spatial coverage for a single basin. This allows us to fully balance the North Sea's Ra budget under consideration of vertical and lateral sources. Combined with data from high-quality core incubations, preliminary results indicate that the Ra dataset can provide estimates of benthic fluxes of Ra, DIC and AT from the extensive shallow mudflat regions of the North Sea. Furthermore, the surface Ra distributions throughout the region can be used to assess dispersion patterns and eventually determine the contribution of DIC and AT from lateral basins. Simulations of the Ra distributions with a passive tracer hydrographic model are used to evaluate analytical results regarding fluxes of both Ra and carbonate species.

  13. 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.

  14. The investigation of properties of short-lived SF isotopes (Z > 100) at the focal plane of VASSILISSA separator

    NASA Astrophysics Data System (ADS)

    Svirikhin, Alexandr; Andreev, Alexander; Dushin, Victor; Chelnokov, Maxim; Chepigin, Victor; Gupta, Mohini; Isaev, Andrey; Izosimov, Igor; Katrasev, Denis; Kuznetsov, Alexey; Malyshev, Oleg; Minkova, Ani; Mullins, Simon; Popeko, Andrey; Sokol, Evgeniy; Yeremin, Alexander

    2013-12-01

    For experiments aimed at the study of spontaneous fission of transfermium nuclei improvements in the focal plane detector system of recoil separator VASSILISSA have been made. A neutron detector consisting of 54 3He-filled counters has been mounted around the focal-plane detector chamber. The reaction 48Ca + 206Pb = 2n + 252No is used for tuning the separator settings and calibrating the detector system with the spontaneous fission of the 252No. The average neutron number per 252No spontaneous fission event is as large as ν̅ = 4.06 ± 0.12. The short-lived heavy isotopes 244,246Fm, produced in the complete fusion reactions 40Ar + 206,208Pb, are investigated. The average number of neutrons per spontaneous fission of 244,246Fm from the experimental data were (ν̅ = 3.3 ± 0.3) and (ν̅ = 3.55 ± 0.50), respectively. Both values are determined for the first time.

  15. 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.

  16. 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 were considerably greater than 224Ra in spite of the expected higher production rate of 224Ra from basalt. 223Ra was not supported by dissolved 227Ac. The highest enrichments of 223Ra were measured over the Puna Ridge (2100 m depth) east of Hawaii. Here 223Ra activities reached 2 dpm/100L, similar to activities measured near sites of active submarine groundwater discharge in the South Atlantic Bight. The high 223Ra values were not associated with significant thermal anomalies. To explain the high activities of 223Ra unaccompanied by 224Ra, we postulate that thermally-driven circulation of sea water through the Puna Ridge deposits 231Pa on basalt surfaces. With time the 231Pa produces 227Ac and 223Ra, which desorbs into circulating fluids. These fluids then transport 223Ra into the overlying ocean. Based on the inventory of 223Ra above the Puna Ridge, we estimate the flow of fluids through the ridge to be on the order of 40cm3cm-2day-1. In less than 100 years the incoming seawater could provide enough 231Pa to basalt surfaces to balance the inventory of 223Ra above the ridge if all of the 223Ra was transported to the overlying water. These observations have significant implications for quantifying fluid fluxes from the flanks of the mid ocean ridge. By mapping 223Ra inventories in the ocean above ridge flanks and the activity of 223Ra in the emerging fluids, the fluid flux can be obtained. These measurements could help resolve the debate of the relative importance of high and low temperature venting from the ridge.

  17. Recent Measurements of Groundwater Recharge and Discharge Through Everglades' Peat Sediments Using Short-Lived Radium Isotopes

    NASA Astrophysics Data System (ADS)

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

    2002-05-01

    Peat sediments are present as a nearly continuous surface layer across large areas of the Everglades. These sediments have relatively low hydraulic conductivity, impeding water exchange between surface water and the underlying surficial aquifer. Although vertical water transport does occur across the peat layer, rates are slow enough that they are difficult to quantify. Even modest rates of vertical transport, however, become significant to water budgets and nutrient cycles when they occur over a large area. In the Everglades, common methods for measuring exchange across the peat layer are prone to complications: small hydraulic gradients are difficult to measure; seepage meters tend to be imprecise at slow rates; radon profiles or emanation rates are complicated by methane bubble ebullition; chloride profiles often exhibit a strong gradient only at the surface of the peat. We are employing a method that takes advantage of the different production rates of short-lived radium isotopes (Ra-223 and Ra-224) in the peat sediments and in the underlying sand or carbonate aquifer. Pore water radium concentrations are balanced by radioactive decay and production in the surrounding sediments. As the pore water is carried across the sediment interface a temporary excess or deficit of dissolved radium exists until decay is again balanced by the new production rate. We have derived steady-state, one-dimensional models to determine flow rates on the basis of this disequilibrium. This method has the advantage of being most sensitive at the base of the peat, away from transient perturbations occurring at the surface. In addition, Ra-223 and Ra-224 are collected simultaneously, providing two independent measurements. At present we have tested the method in Water Conservation Area-1 and WCA-2A, quantifying recharge and discharge on opposite sides of Levee 39, and also in more central sites in WCA-2A. Additional work is underway in Taylor Slough and Shark Slough.

  18. Development of radioactive ion beam production systems for Tokai Radioactive Ion Acceleration Complex-High temperature ion source for short-lived isotopes.

    PubMed

    Otokawa, Y; Osa, A; Sato, T K; Matsuda, M; Ichikawa, S; Jeong, S C

    2010-02-01

    We have developed a new ion source system in the isotope separator on-line at Japan Atomic Energy Agency, for separation of short-lived isotopes produced by proton-induced fission of (238)U. The ion source system is a forced electron beam induced arc discharge version E type ion source with a target container. We successfully operated this system at 2000 degrees C as a result of reductions in volume of the ion source and the target container, introduction of heating method by electron bombardment, and improvement to the heat shield. This new ion source system was tested using (238)U of 640 mg/cm(2) with a proton primary beam of 30 MeV, 350 nA. Release times were measured for Kr, In, and Xe. The values of release times are 2.6 s for Kr, 1.8 s for In, and 4.6 s for Xe. In this work, the ion source system enabled us to mass-separate short-lived isotopes such as (93)Kr(T(1/2)=1.286 s), (129)In(T(1/2)=0.61 s), and (141)Xe(T(1/2)=1.73 s) with intensity of 10(3) ions/s. PMID:20192400

  19. Development of radioactive ion beam production systems for Tokai Radioactive Ion Acceleration Complex--High temperature ion source for short-lived isotopes

    SciTech Connect

    Otokawa, Y.; Osa, A.; Sato, T. K.; Matsuda, M.; Ichikawa, S.; Jeong, S. C.

    2010-02-15

    We have developed a new ion source system in the isotope separator on-line at Japan Atomic Energy Agency, for separation of short-lived isotopes produced by proton-induced fission of {sup 238}U. The ion source system is a forced electron beam induced arc discharge version E type ion source with a target container. We successfully operated this system at 2000 deg. C as a result of reductions in volume of the ion source and the target container, introduction of heating method by electron bombardment, and improvement to the heat shield. This new ion source system was tested using {sup 238}U of 640 mg/cm{sup 2} with a proton primary beam of 30 MeV, 350 nA. Release times were measured for Kr, In, and Xe. The values of release times are 2.6 s for Kr, 1.8 s for In, and 4.6 s for Xe. In this work, the ion source system enabled us to mass-separate short-lived isotopes such as {sup 93}Kr(T{sub 1/2}=1.286 s), {sup 129}In(T{sub 1/2}=0.61 s), and {sup 141}Xe(T{sub 1/2}=1.73 s) with intensity of 10{sup 3} ions/s.

  20. [Short-lived disorders].

    PubMed

    Artigas-Pallares, Josep

    2012-02-29

    Over the years, most of the mental disorders that are dealt with in everyday clinical practice have changed not only their names but also their conceptualisation. Furthermore, as some disorders disappear or are forgotten, others come into being. Seen from a historical perspective and unlike many of the diseases included within classical medicine, it can be stated that one of the basic characteristics of mental disorders is their short-lived presence in the scientific literature. In this study we analyse the causes underlying the transitory nature of mental disorders. The disappearance of a disorder or the modification of how it is conceptualised may be linked to several different motives. Sometimes they may be due to an evolution of the construct, as a result of new findings. On other occasions the disorder falls into disuse owing to the weakness of the theoretical construct or the clinical research upholding it. Lastly, because the Diagnostic and Statistical Manual of Mental Disorders and the International Classification of Diseases require updates that incorporate new contributions and correct faults in the current model, they give rise to new denominations and definitions in mental disorders. This article analyses these three situations and offers an illustrative example in each case. PMID:22374762

  1. Li and B isotopic variations in an Allende CAI: Evidence for the in situ decay of short-lived 10Be and for the possible presence of the short-lived nuclide 7Be in the early solar system

    NASA Astrophysics Data System (ADS)

    Chaussidon, Marc; Robert, François; McKeegan, Kevin D.

    2006-01-01

    The concentrations and isotopic compositions of lithium, beryllium, and boron, analyzed in situ by ion microprobe in 66 spots of a type B1 Ca-Al-rich inclusion (CAI 3529-41) from the Allende meteorite, are reported. Large variations are observed for both the Li and the B isotopic ratios with 7Li/ 6Li ranging from 9.2 ± 0.22 to 12.22 ± 0.43 (a ≈250‰ range in δ7Li values) and 10B/ 11B ranging from 0.2468 ± 0.0057 to 0.4189 ± 0.0493 (a 410‰ range in δ11B values). The very low Li concentrations (<1 ppb) observed in several anorthite and fassaite grains require that a correction for the contribution of spallogenic Li produced during irradiation of the Allende meteoroid by galactic cosmic rays (GCR) be made (after this correction 7Li/ 6Li ranges from 9.2 ± 0.22 to 13.44 ± 0.56, i.e., a ≈350‰ range in δ7Li values). In 3529-41, the 10B/ 11B ratios are positively correlated with 9Be/ 11B in a manner indicating the in situ decay of short-lived 10Be (half-life = 1.5 Ma) with a 10Be/ 9Be ratio at the time of formation of the CAI of 8.8 ± 0.6 × 10 -4, which is in agreement with previous findings [McKeegan, K.D., Chaussidon, M., Robert, F., 2000. Incorporation of short-lived 10Be in a calcium-aluminum-rich inclusion from the Allende meteorite. Science289, 1334-1337]. The present detailed investigation demonstrates that only minor perturbations of the 10Be- 10B system are present in 3529-41, contrary to the 26Al/ 26Mg system for which numerous examples of isotopic redistribution following crystallization were observed [Podosek, F.A., Zinner, E.K., MacPherson, G.J., Lundberg, L.L., Brannon, J.C., Fahey, A.J., 1991. Correlated study of initial 87Sr/ 86Sr and Al-Mg systematics and petrologic properties in a suite of refractory inclusions from the Allende meteorite. Geochim. Cosmochim. Acta55, 1083-1110]. Petrographically based criteria were developed to identify within the 66 analyzed spots in 3529-41, those where post-magmatic perturbation of the Li and Be distributions occurred. Li and Be concentrations measured in different analytical spots are compared with those predicted by using experimentally determined partition coefficients according to a model of closed-system crystallization of the CAI melt. These criteria show that 56% of the spots in melilite, 38% in anorthite, and 8% in fassaite suffered post-crystallization perturbations of Li and/or Be distributions. In the remaining spots, which do not show obvious indication of redistribution of Li or Be, the 7Li/ 6Li isotopic variations (corrected for GCR exposure) are positively correlated with 9Be/ 6Li suggesting the in situ decay of now-extinct 7Be. The derived isochron implies that at the time of its formation, the CAI melt had a 7Be/ 9Be ratio of 0.0061 ± 0.0013 and a 7Li/ 6Li ratio of 11.49 ± 0.13. In contrast, all the spots in 3529-41, which do show evidence for post-magmatic redistribution of Li and Be, have relatively constant 7Li/ 6Li, averaging 11.72 ± 0.56, which is consistent with mass balance calculations for Li isotopic homogenization in the CAI after the decay of 7Be. The incorporation of live 7Be in 3529-41 requires, because of the very short half-life of this nuclide (53 days), that it be produced essentially contemporaneously with the formation of the CAI. Therefore, the irradiation processes responsible for production of 7Be must have occurred within the solar accretion disk. Calculations developed in the framework of the x-wind model [Gounelle, M., Shu, F.H., Shang, H., Glassgold, A.E., Rehm, E.K., Lee, T., 2004. The origin of short-lived radionuclides and early Solar System irradiation (abstract). Lunar Planet. Sci.35, 1829] reproduce the 7Be and 10Be abundances observed in 3529-41. The correlated presence of 7Be and 10Be in 3529-41 is thus a strong argument that 10Be, which is observed rather ubiquitously in CAIs, is also a product of irradiation in the early solar system, as might be a significant fraction of other short-lived radionuclides observed in early solar system materials.

  2. 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.

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

    PubMed

    Nrtershuser, Wilfried; Geppert, Christopher; Krieger, Andreas; Pachucki, Krzysztof; Puchalski, Mariusz; Blaum, Klaus; Bissell, Mark L; Frmmgen, Nadja; Hammen, Michael; Kowalska, Magdalena; Krmer, Jrg; Kreim, Kim; Neugart, Rainer; Neyens, Gerda; Snchez, 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 m?(6) and m?(7)??ln??. 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

  4. Degassing processes and eruptive activity at Merapi volcano: The bearing of short-lived U-series isotopes.

    NASA Astrophysics Data System (ADS)

    Gauthier, P. J.; Le Cloarec, M. F.

    2003-04-01

    For more than 20 years, volcanic gases have been regularly collected at Merapi volcano (Central Java, Indonesia) and subsequently analyzed for their radionuclide (210Pb, 210Bi, and 210Po) and SO_2 contents. Gas sampling was carried out during various periods of contrasted volcanic activity and at different locations: high-temperature fumarolic fields (Woro: 600^oC; Gendol 850^oC), main plume released through fractures within the summit crater, and active growing lava domes. These new results show the high volatility of the three radionuclides in andesitic gases, although their emanation coefficients (0.94%, 3.5%, and <= 53% for 210Pb, 210Bi, and 210Po, respectively) are significantly lower than those observed at basaltic volcanoes. This emphasizes the major role of magma temperature on the degassing of these metals, which are mainly transported in volcanic gases as Pb-chloride compounds, and Bi- and Po-metallic species. 210Pb--210Bi--210Po radioactive disequilibria in the gas phase at Merapi appear to be characteristic of the degassing processes and gas paths within the edifice. Gases released at both Gendol and Woro fumarolic fields are clearly of magmatic origin, but their 210Pb--210Bi--210Po isotopic signature is strongly altered by secondary processes: condensation and transformation of gases crossing brines (Woro); deposition and subsequent degassing of sublimates according to temperature variations in the ground (Woro, Gendol). High-temperature gases collected in the main plume are of pure primary magmatic origin. They are likely directly tapped in the degassing reservoir and escape through the main fractures with little interaction with the dome-forming host rocks. On the other hand, gases arising from the growing dome are strongly depleted in the most volatile isotopes and gas species. We conclude from these observations that lava is almost completely degassed prior to its emission at the surface, and that magmatic degassing at Merapi is an open-system process, which explains why the volcano usually undergoes no explosive eruptions. The 210Pb flux released in the main gas plume in 1995 is accounted for by the daily degassing of 25,000 m^3 of deep magma, supplied in a shallow reservoir of 1.8* 10^7 m^3. This deep magma supply is twice the extrusion rate of lava at the surface, which means that unerupted degassed magma progressively accumulates beneath the summit. This leads to the build-up of an overpressure which has potential, when it exceeds the mechanical resistance of the dome, to trigger dome collapse without any warning, as for the November 22, 1994 catastrophic eruption.

  5. 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.

  6. 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.

  7. 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.

  8. 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 ?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. ?groundmss/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-hydrothermal event that was focused within the upper 750 m of intracaldera tuff. Mass balance calculations indicate fluid fluxes of ? 6 10 -6 molcm -2 s -1. We believe that the closest historical analogue to this Chegem hydrothermal event is the situation observed in the Valley of Ten Thousand Smokes (Alaska, USA), where hundreds of steam fumaroles with measured temperatures as high as 645 C persisted for 10 to 15 years in the much smaller welded ash-flow tuff sheet (? 200 m thick) produced by the 1912 Katmai eruption.

  9. 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., Jr.; 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 focused within the upper 750 m of intracaldera tuff. Mass balance calculations indicate fluid fluxes of = 6 ?? 10-6 mol cm-2 s-1. We believe that the closest historical analogue to this Chegem hydrothermal event is the situation observed in the Valley of Ten Thousand Smokes (Alaska, USA), where hundreds of steam fumaroles with measured temperatures as high as 645??C persisted for 10 to 15 years in the much smaller welded ash-flow tuff sheet (??? 200 m thick) produced by the 1912 Katmai eruption.

  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. 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.

  12. Fe-Ni and Al-Mg isotope records in UOC chondrules: Plausible stellar source of 60Fe and other short-lived nuclides in the early Solar System

    NASA Astrophysics Data System (ADS)

    Mishra, R. K.; Goswami, J. N.

    2014-05-01

    The short-lived now-extinct nuclide 60Fe, present in the early Solar System, is a unique product of stellar nucleosynthesis. Even though the first hint for its presence in the early Solar System was obtained more than two decades back, a robust value for Solar System initial (SSI) 60Fe/56Fe is yet to be established. A combined study of 26Al-26Mg and 60Fe-60Ni isotope systematics in chondrules from unequilibrated ordinary chondrites of low petrologic type, Semarkona (LL3.0), LEW 86134 (L3.0), and Y 791324 (L3.1), has been conducted to infer the value of SSI 60Fe/56Fe. Seven of the analysed chondrules host resolved radiogenic excess in both 60Ni and 26Mg resulting from in situ decay of the short-lived nuclides 60Fe and 26Al, respectively. The initial 26Al/27Al values for these chondrules range from (6.9 ± 5.8) × 10-6 to (3.01 ± 1.78) × 10-5 that suggest their formation between 2.1 and 0.6 Ma after CAIs. The initial 60Fe/56Fe at the time of formation of these chondrules ranges from (3.2 ± 1.3) × 10-7 to (1.12 ± 0.39) × 10-6 and show a good correlation with their initial 26Al/27Al values suggesting co-injection of the two short-lived nuclides, 60Fe and 26Al, into the protosolar cloud from the same stellar source. Considering 26Al as a reliable early Solar System chronometer, this data set yield a SSI 60Fe/56Fe value of (7.0 ± 1.2) × 10-7, if we adopt a half-life value of 2.6 Ma for 60Fe reported in a recent study. Model stellar nucleosynthesis yields suggest that both a high mass (5-6.5 M⊙) Asymptotic Giant Branch (AGB) star or a supernova (SN) could be the source of 60Fe and 26Al present in the early Solar System. A high mass (˜25 M⊙) SN appears more plausible because of the much higher probability of its close association with the protosolar molecular cloud than a high mass AGB star. Such a SN can also account for SSI abundance of 26Al and its correlated presence with 60Fe in chondrules.

  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. EVOLUTION OF THE SOLAR NEBULA. IX. GRADIENTS IN THE SPATIAL HETEROGENEITY OF THE SHORT-LIVED RADIOISOTOPES {sup 60}Fe AND {sup 26}Al AND THE STABLE OXYGEN ISOTOPES

    SciTech Connect

    Boss, Alan P.

    2011-10-01

    Short-lived radioisotopes (SLRIs) such as {sup 60}Fe and {sup 26}Al were likely injected into the solar nebula in a spatially and temporally heterogeneous manner. Marginally gravitationally unstable (MGU) disks, of the type required to form gas giant planets, are capable of rapid homogenization of isotopic heterogeneity as well as of rapid radial transport of dust grains and gases throughout a protoplanetary disk. Two different types of new models of an MGU disk in orbit around a solar-mass protostar are presented. The first set has variations in the number of terms in the spherical harmonic solution for the gravitational potential, effectively studying the effect of varying the spatial resolution of the gravitational torques responsible for MGU disk evolution. The second set explores the effects of varying the initial minimum value of the Toomre Q stability parameter, from values of 1.4 to 2.5, i.e., toward increasingly less unstable disks. The new models show that the basic results are largely independent of both sets of variations. MGU disk models robustly result in rapid mixing of initially highly heterogeneous distributions of SLRIs to levels of {approx}10% in both the inner (<5 AU) and outer (>10 AU) disk regions, and to even lower levels ({approx}2%) in intermediate regions, where gravitational torques are most effective at mixing. These gradients should have cosmochemical implications for the distribution of SLRIs and stable oxygen isotopes contained in planetesimals (e.g., comets) formed in the giant planet region ({approx}5 to {approx}10 AU) compared to those formed elsewhere.

  15. 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).

  16. Precision mass measurements of short-lived nuclides for nuclear structure studies at TITAN

    NASA Astrophysics Data System (ADS)

    Chaudhuri, A.; Andreoiu, C.; Brunner, T.; Chowdhury, U.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Gwinner, G.; Klawitter, R.; Kwiatkowski, A. A.; Leach, K. G.; Lennarz, A.; Lunney, D.; Macdonald, T. D.; Schultz, B. E.; Seeraji, S.; Simon, M. C.; Simon, V. V.; Dilling, J.

    2014-03-01

    TITAN (TRIUMF's Ion Trap for Atomic and Nuclear science) at TRIUMF's rare isotope beam facility ISAC is an advanced Penning trap based mass spectrometer dedicated to precise and accurate mass determinations. An overview of TITAN, the measurement technique and a highlight of recent mass measurements of the short-lived nuclides important to the nuclear structure program at TITAN are presented.

  17. 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.

  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. 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.

  20. 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.

  1. 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

  2. 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.

  3. Inorganic biochemistry with short-lived radioisotopes as nuclear probes

    NASA Astrophysics Data System (ADS)

    Trger, W.; Butz, T.

    2000-12-01

    Metal ions are ubiquitous in the biosphere. In living organisms metalloproteins with specifically designed metal cores perform vital chemical processes. On the other hand, several heavy metals are detrimental to living organisms and nature has developed effective enzymatic detoxification systems which convert toxic metal ions to less toxic species. The nuclear spectroscopy technique Time Differential Perturbed Angular Correlation (TDPAC) of ?-rays uses radioactive isotopes as nuclear probes in these metal cores to obtain a better understanding of the structural and functional significance of these metal cores by monitoring the nuclear quadrupole interaction of the TDPAC probe. Since this technique is based on the nuclear decay, it is also applicable under physiological conditions, i.e., especially at picomolar concentrations. For these studies an indispensable prerequisite is the production of the TDPAC probes with highest possible specific activity and purity as is done by the on-line mass separator ISOLDE at CERN in Geneva.

  4. 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)

  5. Extension of NCRP 129 to short-lived radionuclides.

    PubMed

    Arno, M G; Kercher, J R; Cederwall, R T; Loosmore, G A

    2004-08-01

    NCRP 129 contains dose conversion factors for 200 radionuclides that allow one to estimate the maximum dose to an individual based on the concentration of the radionuclide in the soil and the way in which the land is used. The methodology of NCRP 129 has been extended to be applicable to 28 common short-lived radionuclides and their progeny, and dose conversion factors were obtained for these radionuclides. In addition to applying the NCRP 129 calculational methodology to these radionuclides, holdup times from harvest or slaughter until consumption have been incorporated into the decay correction equations used to determine the maximum annual dose due to the significance of the holdup time with respect to the dose from short-lived radionuclides. These holdup times were included in the Monte Carlo sampling regimen used in NCRP 129. A test using emission rates proportional to those of the Chernobyl event indicated that areas of high dose, where rainout occurs, more than doubled in areas where short-lived radionuclides from this study were included. PMID:15257214

  6. Neutron Stars as a Source of the Short-Lived Nuclides in Ap-star Atmospheres

    SciTech Connect

    Gopka, Vera F.; Andrievsky, Sergey M.; Ulyanov, Oleg M.

    2008-05-21

    We propose a new explanation of some magnetic chemically peculiar (MCP) star anomalies, which is based on an assumption that such stars be the close binary systems with a secondary component being a neutron star. Within this hypothesis one can naturally explain the main anomalous features of MCP stars: first of all, an existence of the short-lived radioactive isotopes detected in some stars (like Przybylski's star (PS) and HR465), and some others peculiarities. Also we can assume the presence of the electron-positron annihilation emission lines (0.511 MeV) in the gamma spectrum of some MCP stars.

  7. Near-term climate mitigation by short-lived forcers

    PubMed Central

    Smith, Steven J.; Mizrahi, Andrew

    2013-01-01

    Emissions reductions focused on anthropogenic climate-forcing agents with relatively short atmospheric lifetimes, such as methane (CH4) and black carbon, have been suggested as a strategy to reduce the rate of climate change over the next several decades. We find that reductions of methane and black carbon would likely have only a modest impact on near-term global climate warming. Even with maximally feasible reductions phased in from 2015 to 2035, global mean temperatures in 2050 would be reduced by 0.16 C, with a range of 0.040.35 C because of uncertainties in carbonaceous aerosol emissions and aerosol forcing per unit of emissions. The high end of this range is only possible if total historical aerosol forcing is relatively small. More realistic emission reductions would likely provide an even smaller climate benefit. We find that the climate benefit from reductions in short-lived forcing agents are smaller than previously estimated. These near-term climate benefits of targeted reductions in short-lived forcers are not substantially different in magnitude from the benefits from a comprehensive climate policy. PMID:23940357

  8. Near-Term Climate Mitigation by Short-Lived Forcers

    SciTech Connect

    Smith, Steven J.; Mizrahi, Andrew H.

    2013-08-12

    Emissions reductions focused on anthropogenic climate forcing agents with relatively short atmospheric lifetimes such as methane (CH4) and black carbon (BC) have been suggested as a strategy to reduce the rate of climate change over the next several decades. We find that reductions of methane and BC would likely have only a modest impact on near-term climate warming. Even with maximally feasible reductions phased in from 2015 to 2035, global mean temperatures in 2050 are reduced by 0.16 °C, with an uncertainty range of 0.04-0.36°C, with the high end of this range only possible if total historical aerosol forcing is small. More realistic mitigation scenarios would likely provide a smaller climate benefit. The climate benefits from targeted reductions in short-lived forcing agents are smaller than previously estimated and are not substantially different in magnitude from the benefits due to a comprehensive climate policy.

  9. ``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.

  10. Magnetic Resonance of short-lived negative ions

    NASA Astrophysics Data System (ADS)

    Toader, Emil; Stalder, Kenneth; Graham, Bill

    2003-10-01

    Here we present the possibility of creating short-lived (labile or exotic) negative ions, from the scattering of free electrons and polarized molecules in a discharge. In the interaction the electrons do not loose energy. Their mechanism of formation, structure and stability are completely different from those corresponding to stable negative ions. A classical analysis, based on an effective potential with a centrifugal term and a polarized term, shows that low energy electrons can orbit for some time around a polarized molecule. A quantum mechanics model shows that such labile negative ions can be in states that are characterized by the molecular quantum mechanics numbers K (rotational) and J (total), and the electron quantum numbers l (orbital) and j (total). The molecule is in the magnetic field created by the rotating electron, and can change its magnetic moment, so the short-lived negative ion can make the transitions between the different rotational states. Each transition corresponds to a variation of the magnetic energy, so we can have a doublet transition both in emission and absorption, at radio-frequencies from 1 to 150 MHz in deuterium and oxygen . The dispersion curves are specific to each polarized molecule and the transition frequencies can be measured using resonant detection methods.

  11. 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.

  12. 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.

  13. Feasibility of short-lived radionuclide production at Fermilab

    SciTech Connect

    Ten Haken, R.K.; Awschalom, M.; Rosenberg, I.

    1982-04-29

    The feasibility of establishing a facility for short-lived radionuclide production hinges on the availability of the Fermilab injector linac and on how such a program would fit in with the primary mission of the laboratory. The linac is available 168 hours per week except for scheduled maintenance, which typically does not exceed one to two shifts per week, and HEP requirements. The laboratory may be reluctant to make a commitment for the routine production of SLRs however, due to its understanding of the requirements for reliable scheduled delivery of targets. But, the laboratory is also quite interested in establishing industrial liaisons. It would be willing to explore feasible industrial proposals, especially with regards to developing a research-type facility where the technology and methods developed at Fermilab could be utilized elsewhere.

  14. Detection Of Short-Lived Particles Using Holography

    NASA Astrophysics Data System (ADS)

    Haridas, P.; Hafen, E.; Pless, I.; Harton, J.; Dixit, S.; Goloskie, D.; Benton, S.

    1985-08-01

    Vertex detectors with good spatial resolution are ideal devices for the detection of short-lived particles (mean lifetime > 10-13 s; mean distance traveled before decay- um) produced in high energy interactions. The bubble chamber equipped with high resolution photography is one such vertex detector. However, improving the resolution in photography results in a very rapid decrease of the depth of field, thereby rendering most of the chamber optically inaccessible. Using holography instead of photography remedies this problem by decoupling resolution and depth of field. This paper reports on our recent work in the use of a two-beam holographic technique for a large Freon bubble chamber (80 cm in diameter and 100 cm deep). The results reported here are for a full-scale setup in air with test targets to simulate bubble chamber tracks and in some cases a full-scale 28 cm thick glass plate to simulate chamber windows. This bubble chamber is the vertex detector for a hybrid spectrometer system that will be used for two of our forthcoming experiments at the Fermi National Accelerator Laboratory: the first to search for the short-lived charmed particles and the second to establish the existence of the T neutrino by observing the decay of the T lepton. We demonstrate that a 30 resolution can be achieved throughout the entire volume of the chamber. Specific details pertinent to achieving this resolution are also discussed. We also report on the construction of a semiautomated high precision measuring apparatus that will be used to scan and measure bubble chamber holograms.

  15. 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.

  16. 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.

  17. Quantifying Short-Lived Events in Multistate Ionic Current Measurements

    PubMed Central

    2015-01-01

    We developed a generalized technique to characterize polymer–nanopore interactions via single channel ionic current measurements. Physical interactions between analytes, such as DNA, proteins, or synthetic polymers, and a nanopore cause multiple discrete states in the current. We modeled the transitions of the current to individual states with an equivalent electrical circuit, which allowed us to describe the system response. This enabled the estimation of short-lived states that are presently not characterized by existing analysis techniques. Our approach considerably improves the range and resolution of single-molecule characterization with nanopores. For example, we characterized the residence times of synthetic polymers that are three times shorter than those estimated with existing algorithms. Because the molecule’s residence time follows an exponential distribution, we recover nearly 20-fold more events per unit time that can be used for analysis. Furthermore, the measurement range was extended from 11 monomers to as few as 8. Finally, we applied this technique to recover a known sequence of single-stranded DNA from previously published ion channel recordings, identifying discrete current states with subpicoampere resolution. PMID:24397836

  18. 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.

  19. 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 sedimentary organic matter from the core is used to identify further changes in environment and vegetation. From the base to the top of the formation, there is a gradual increase in relatively drier conditions, with more developed palaeosols and deep desiccation cracks. However, the main character of the formation is that of rapidly changing deposition between silts, sands and carbonates with many periods of pedogenesis and/or desiccation suggesting frequent switching from alluvial-plain to coastal environments. Marine incursions were short-lived, but important and caused a significant increase in the macro and microfaunal diversity. This temporal variability in the environments may have been an important factor in the evolution of tetrapods in the Early Carboniferous.

  20. 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.

  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. Chernobyl-related thyroid cancer: what evidence for role of short-lived iodines?

    PubMed Central

    Bleuer, J P; Averkin, Y I; Abelin, T

    1997-01-01

    Over 500 cases of thyroid cancer were diagnosed in Belarus between 1986 and 1995 among persons exposed as children (under 15 years of age) to radioactive contamination from the Chernobyl nuclear accident. There is little doubt that radioactive iodine isotopes emitted during the nuclear explosion and subsequent fire were instrumental in causing malignancy in this particular organ. Comparison of the observed geographic distribution of Chernobyl-associated thyroid cancer incidence rates by districts with contamination maps of radioactive fallout shows a better fit for estimated 131I contamination than for 137Cs. Because 131I used for medical purposes had not been considered carcinogenic in humans in the past, and in view of the unusually short latency period between exposure and clinical manifestation of cancer, it is suspected that not only 131I but also energy-rich shorter-lived radioiodines may have played a role in post-Chernobyl thyroid carcinogenesis. Measurements of iodine isotopes are not available, but reconstruction of geographic distributions and estimations of radioactive fallout based on meteorological observations immediately following the accident could provide a basis for comparison with the distribution of thyroid cancer cases. In this paper, data from the Epidemiological Cancer Register for Belarus will be used to show geographic and time trends of thyroid cancer incidence rates in the period from 1986 to 1995 among persons who were exposed as children, and these will be compared with the estimated contamination by radioiodines. Tentative conclusions are drawn from the available evidence and further research requirements discussed. PMID:9467068

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Short-lived nuclei in the early Solar System: Possible AGB sources

    NASA Astrophysics Data System (ADS)

    Wasserburg, G. J.; Busso, M.; Gallino, R.; Nollett, K. M.

    2006-10-01

    The abundances of short-lived radionuclides in the early Solar System (ESS) are reviewed, as well as the methodology used in determining them. These results are compared with the inventory estimated for a uniform galactic production model. It is shown that, to within a factor of two, the observed abundances of 238U, 235U, 232Th, 244Pu, 182Hf, 146Sm, and 53Mn are roughly compatible with long-term galactic nucleosynthesis. 129I is an exception, with an ESS inventory much lower than expected from uniform production. The isotopes 107Pd, 60Fe, 41Ca, 36Cl, 26Al, and 10Be require late addition to the protosolar nebula. 10Be is the product of energetic particle irradiation of the Solar System as most probably is 36Cl. Both of these nuclei appear to be present when 26Al is absent. A late injection by a supernova (SN) cannot be responsible for most of the short-lived nuclei without excessively producing 53Mn; it can however be the source of 53Mn itself and possibly of 60Fe. If a late SN injection is responsible for these two nuclei, then there remains the problem of the origin of 107Pd and several other isotopes. Emphasis is given to an AGB star as a source of many of the nuclei, including 60Fe; this possibility is explored with a new generation of stellar models. It is shown that if the dilution factor (i.e. the ratio of the contaminating mass to the solar parental cloud mass) is f410, a reasonable representation for many nuclei is obtained; this requires that (60Fe/56Fe)ESS 10-7 to 210. The nuclei produced by an AGB source do not include 53Mn, 10Be or 36Cl if it is very abundant. The role of irradiation is discussed with regard to 26Al, 36Cl and 41Ca, and the estimates of bulk solar abundances of these isotopes are commented on. The conflict between various scenarios is emphasized as well as the current absence of an astrophysically plausible global interpretation for all the existing data. Examination of abundances for the actinides indicates that a quiescent interval of 10 yr is required for actinide group production. This is needed in order to explain the data on 244Pu and the new bounds on 247Cm. Because this quiescent interval is not compatible with the 182Hf data, a separate type of r-process event is needed for at least the actinides, distinct from the two types that have previously been identified. The apparent coincidence of the 129I and trans-actinide time scales suggests that the last heavy r contribution was from an r-process that produced very heavy nuclei but without fission recycling so that the yields at Ba and below (including I) were governed by fission.

  11. Short-lived isomers in {sup 94}Rb

    SciTech Connect

    Tsekhanovich, I.; Dare, J. A.; Smith, A. G.; Varley, B. J.; Simpson, G. S.; Urban, W.; Soldner, T.; Jolie, J.; Linnemann, A.; Orlandi, R.; Smith, J. F.; Scherillo, A.; Rzaca-Urban, T.; Zlomaniec, A.; Dorvaux, O.; Gall, B. J. P.; Roux, B.

    2008-07-15

    The medium-spin structure of the neutron-rich, odd-odd nucleus {sup 94}Rb was studied by means of {gamma}-ray spectroscopy. Excited levels were populated in the neutron-induced fission of {sup 235}U and in the spontaneous fission of {sup 252}Cf and {sup 248}Cm. Two isomeric states were found at 1485.2 and 2074.8 keV with half-lives of 18 and 107 ns, respectively. The probable structures of the two isomers involve the fully aligned, proton-neutron configurations [{pi}(g{sub 9/2}) x {nu}(g{sub 7/2})]{sub 8{sup +}} and [{pi}(g{sub 9/2}) x {nu}(h{sub 11/2})]{sub 10{sup -}}, respectively. These new data give information on the single-particle energies in the region.

  12. Natural gamma radiation from long-lived actinide isotopes

    SciTech Connect

    Dupree, S.A.; Sanger, H.M.

    1987-06-01

    The purpose of this report is to describe a method, developed at Sandia National Laboratories, for calculating volumetric, unshielded, gamma radiation source spectra with arbitrary energy group structures from essentially arbitrary mixtures of actinide isotopes. The computer code and data base are combined as INRAD. These spectra can be used to describe the source for gamma radiation transport codes. Coupled with this source routine is a special version of the one-dimensional, discrete ordinates, radiation transport code XSDRN that uses the spectrum generating routine to define sources in an appropriate energy group structure. 15 refs., 34 figs., 10 tabs.

  13. 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.

  14. 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.

  15. Convection of Very Short Lived Trace Gases into the TTL, UT and LS.

    NASA Astrophysics Data System (ADS)

    Moore, F. L.; Dutton, G. S.; Elkins, J. W.; Hall, B. D.; Hurst, D. F.; Nance, J. D.

    2007-12-01

    The Tropical Tropopause Layer (TTL) can be isolated from the free troposphere for days to a month. Measurements of trace gases with similar local lifetimes of days to a month within the upper troposphere (UT), TTL, and lower stratosphere (LS) can identify convective events and reveal information about primary entry points, possible entrainment, and convective outflow. Episodic evidence of convective transport of Very Short Lived Species (VSLS) from the boundary layer to the UT and LS have been seen before. With CH3I for example, evidence for convection occurs primarily if the dominant convective inflow is from a source region within the boundary layer. This episodic data coupled with the host of measurements in missions like Tropical Composition, Cloud, and Climate Coupling experiment (TC4), will continue to improve our understanding of the convective process. At present, a gap exists between this episodic event driven data and an extrapolation to mean distributions and bulk transport. Trace gases like peroxylacytyl nitrate (PAN) have the potential to bridge this gap and may be more suited for integrated zonal comparisons. PAN is unique in two ways. First its lifetime in the TTL is on the order of the upper limit of the residence time of the TTL, and can survive a zonal trip around the globe. The value of PAN measured in the upper troposphere and lower stratosphere therefore contains a statistical distribution from zonal sources, sinks and convection, from within this month timescale. A second difference is that unlike most VSLS species, the source region for PAN extends above the trapped bounder layer. PAN measurements in the UT and TTL are therefore sensitive to convective inflow above the boundary layer in the lower troposphere, as is also the case for water isotope measurements. Most convective processes are highly turbulent with substantial entrainment expected. The dominant convective mass flux into the TTL may not come from the trapped boundary layer where most VSLS are prevalent.

  16. {beta}-decay half-lives of new neutron-rich lanthanide isotopes

    SciTech Connect

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

    1998-12-21

    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. The observed K x-rays following the {beta}{sup -}decay of products in the mass separated fraction provided direct isotopic identifications. New isotopes observed, with values of their half-lives given in parentheses, are {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 half-life values are compared to the results of theoretical predictions.

  17. Constraints on the Origin of Chondrules and CAIs from Short-lived and Long-lived Radionuclides

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    In order to understand the timing of events in the early solar system, we rely on the radio-nuclide-based chronometers applied to materials in primitive meteorites. Because the time scale of early-solar system evolution was on the order of a few million years (Myr), we focus on so-called "short-lived radionuclides" with mean lives of less than 10 Myr (Table 1), as well as on the long-lived U-Pb system where high precision 207Pb-206Pb ages are applied. Note that the validity of some systems as chronometers (e.g., Be-B, Fe-Ni) has yet to be established. We summarize literature data for chondrules and CAIs and discuss how these chronometers constrain formation time scales in the early solar system.

  18. Impact of Reducing Short-Lived Air Pollutants on Atmospheric Composition and Climate

    NASA Astrophysics Data System (ADS)

    Naik, V.; Horowitz, L. W.; Fiore, A. M.; Levy, H.

    2010-12-01

    Most studies to date have quantified the impact of short-lived air pollutants on climate in terms of radiative forcing, where radiative forcing is calculated based on changes in forcing agent distributions induced by emission perturbations simulated in a chemistry-transport model (CTM). Here, we employ the GFDL AM3 model to investigate the impact of a change in the emissions of short-lived air pollutants on the coupled chemistry-climate system (including stratospheric and tropospheric chemistry, and cloud-aerosol interactions). We present results from two simulations conducted in support of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The base case simulation uses prescribed mean 1981-2000 sea surface temperatures and sea ice cover taken from the historical simulations conducted for the Coupled Model Intercomparison Project 5 (CMIP5) in support of the IPCC-AR5. Concentrations of well-mixed greenhouse gases, ozone depleting substances, and emissions of short-lived pollutants are for the year 2000. The perturbation simulation uses the same configuration except the short-lived pollutant emissions are reduced to 1860 values (77% decrease for NOx, 54% decrease for CO, 70% NMVOCs, 95% SO2, 58% BC and 35% OC). Our initial analysis indicates that the troposphere and stratosphere respond in opposite ways to the reduction in short-lived pollutants. While tropospheric ozone burden decreases (by 18% or 64 Tg on an annual average), stratospheric ozone increases, particularly over the poles. This pre-industrial to present change in tropospheric ozone is somewhat smaller than prior CTM estimates, suggesting an important influence from stratosphere-troposphere interactions. We will examine the differences in atmospheric circulation, temperature and precipitation, stratosphere-troposphere exchange, oxidizing capacity and aerosol distributions in the two simulations, with the goal of advancing our understanding of the role of short-lived pollutants in the coupled chemistry-climate system.

  19. Advanced short-lived nuclide NAA with application in the life sciences.

    PubMed

    Papadopoulos, N N; Tsagas, N F

    1994-01-01

    A new technique for short-lived nuclide activation analysis has been developed that compensates the rapid radioactive decay during the counting period by simultaneous approach of the sample holder to the detector with a mechanical device, permitting prolongation of the counting time and reduction of the required complementary cyclic activation to avoid sample container damage. The operation of the analytical system is automated by a programmable logic controller (PLC). This improvement of short-lived nuclide activation analysis, providing a high throughput, is important in biological and environmental research, where often a large number of samples has to be analyzed for sufficient sampling statistics. PMID:7710819

  20. 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.

  1. 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

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

    PubMed

    Matzkin, Mara Eugenia; Miquet, Johanna Gabriela; Fang, Yimin; Hill, Cristal Monique; Turyn, Daniel; Calandra, Ricardo Sal; Bartke, Andrzej; Frungieri, Mnica 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

  3. Processes regulating short-lived species in the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Gettelman, A.; Lauritzen, P. H.; Park, M.; Kay, J. E.

    2009-07-01

    A one-dimensional model of vertical transport in the tropical tropopause layer (TTL) is developed. The model uses vertical advection, a convective source, and a chemical sink to simulate the profiles of very short lived substances in the TTL. The model simulates evanescent profiles of short-lived hydrocarbon species observed by satellite and is also used to simulate short-lived bromine species. Tracers with chemical lifetimes of 25 days or longer have significant concentrations in the stratosphere, and vertical advection is critical. Convection is important up to its peak altitude, nearly 19 km. Convection dominates the distribution of species with lifetimes less than 25 days. The annual cycle of species with lifetimes longer than 25 days is governed primarily by the variations of vertical velocity, not convection. This is particularly true for carbon monoxide, where a seasonal cycle in the lower stratosphere of the right phase is produced without variations in tropospheric emissions. An analysis of critical short-lived bromine species (CH2Br2 and CHBr3) indicates that substantial amounts of these tracers may get advected into the lower stratosphere as source gases at 18 km, and are estimated to contribute 2.8 pptv (1.1-4.1) to stratospheric bromine.

  4. Processes regulating short-lived species in the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Gettelman, A.; Kay, J. E.; Lauritzen, P.; Park, M.

    2009-12-01

    A one-dimensional model of vertical transport in the tropical tropopause layer (TTL) is presented to better understand the processes controlling short lived species in the TTL. The model simulates evanescent profiles of short-lived hydrocarbon species observed by satellite and is also used to simulate short-lived bromine species. Results indicate that tracers with chemical lifetimes of 25 days or longer have significant concentrations in the stratosphere, and vertical advection is critical. Convection is important up to its peak altitude, nearly 19 km. Convection dominates the distribution of species with lifetimes less than 25 days. The annual cycle of species with lifetimes longer than 25 days is governed primarily by the variations of vertical velocity, not convection. This is particularly true for carbon monoxide, where a seasonal cycle in the lower stratosphere of the right phase is produced without variations in tropospheric emissions. An analysis of critical short-lived bromine species (CH2Br2 and CHBr3) indicates that substantial amounts of these tracers may get advected into the lower stratosphere as source gases at 18 km, and contribute significantly to stratospheric bromine.

  5. Synthesis of radiopharmaceuticals containing short-lived radionuclides. Progress report, March 1, 1985-February 26, 1986

    SciTech Connect

    Kabalka, G.W.

    1985-09-01

    Methods for the rapid introduction of short-lived radionuclides into agents for use in diagnostic nuclear medicine are reported. Methods to synthesize radioiodinated fatty acids, lipids, and amphetamine derivatives are described. New routes for the introduction of bromine-77, chlorine-34m, and carbon-11 into agents of interest are elaborated. 46 refs.

  6. Synthesis of radiopharmaceuticals containing short-lived radionuclides. Comprehensive report, March 1, 1980-February 26, 1986

    SciTech Connect

    Kabalka, G.W.

    1985-09-01

    New methods for the rapid introduction of short-lived radionuclides into agents for use in diagnostic nuclear medicine are reported. Among the new syntheses reported are those for /sup 123/I-labeled fatty acids and steroids, for /sup 11/C-labeled alcohols, for /sup 13/N-labeled amines, and for /sup 15/O-labeled alcohols. 33 refs.

  7. A 3-D model for assessing ozone depletion potentials of short-lived fumigants

    SciTech Connect

    Olaguer, E.P.

    1995-12-31

    Scientific and regulatory assessments of stratospheric ozone depletion have relied on 2-D, 1-D and even 0-D atmospheric models. These tools are at best applicable to long-lived compounds and are inappropriate for chemicals with life-times of the order of one year or less. This paper will discuss the capabilities of an efficient 3-D meteorological-chemical model for simulating the stratospheric impacts of short-lived fumigants and their atmospheric degradation products. The model has the unique feature of simultaneously coupling radiative, chemical and dynamical processes in the stratosphere and troposphere. It can be used to derive policy indices such as ozone depletion potential and global warming potential, and to assess perturbations in atmospheric composition, radiative forcing and surface ultraviolet flux due to short-lived anthropogenic compounds.

  8. Relatively Long-Lived Dubnium Isotopes and Chemical Identification of Superheavy Elements

    SciTech Connect

    Tereshatov, E. E.; Voronyuk, M. G.; Starodub, G. Ya.; Petrushkin, O. V.; Dmitriev, S. N.; Bruchertseifer, H.

    2010-04-30

    The present study has been performed within the framework of experiments aimed at the investigation of chemical properties of long-lived Db isotopes in aqueous solutions. The isocratic anion exchange separations of group V elements in the solutions containing HF have been considered. Parameters of separation of dubnium homologues (Pa, Nb and Ta) in HF/HNO{sub 3} mixed solutions have been optimized. The procedure of separation of group V elements from multicomponent system has been suggested.

  9. 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

  10. Mitigation of short-lived heating components may lead to unwanted long-term consequences

    NASA Astrophysics Data System (ADS)

    Myhre, Gunnar; Fuglestvedt, Jan S.; Berntsen, Terje K.; Lund, Marianne T.

    2011-10-01

    A mitigation strategy for reducing emissions of short-lived heating components such as black carbon (BC) aerosols and ozone precursors to limit global warming has frequently been suggested ( Bond, 2007; Grieshop et al., 2009; Hansen et al., 2000; Jacobson, 2002; Molina et al., 2009; Nature Editorial, 2009). BC emissions influence the radiative balance in several ways through direct and semi-direct aerosol effects, as well as by impacting the surface albedo ( Forster et al., 2007), and their net effect is likely a warming that enhances the total man-made warming. However, the role that BC or other short-lived heating components may play in future mitigation strategies must be formulated with caution to avoid unforeseen and unwanted consequences. A near-term mitigation of short-lived heating components could lead to a delayed action on CO 2 and other long-lived greenhouse gases and thus an increased long-term warming. A key element is whether policies are designed as a consequence of predicted warming or observed warming. Without a clear strategy, early BC or ozone reductions may even lead to an unexpectedly larger temperature change.

  11. Analyses of new short-lived replacements for HFCs with large GWPs

    NASA Astrophysics Data System (ADS)

    Wuebbles, Donald J.; Wang, Dong; Patten, Kenneth O.; Olsen, Seth C.

    2013-09-01

    this study, we examine the atmospheric lifetimes and Global Warming Potentials (GWPs) for six short-lived potential ozone-depleting substances and high-GWP hydrofluorocarbons (HFCs) replacement compounds and evaluate the potential reduced effects on climate forcing from adopting such compounds. We also examine the potential effects on climate from widespread use of these chemicals. The atmospheric lifetimes of these compounds are each less than 1 month and their 100 year GWPs range from 0.9 to 4.6. The derived GWPs are substantially lower than those in prior published studies, which used simplified estimation techniques that overestimate the GWPs for these short-lived compounds by 61% to 237%. If long-lived HFCs are completely replaced with these substitute compounds, radiative forcing of these short-lived compounds in 2050 will be 0.26 to 0.80 mW m-2, a factor of as much as 1000 smaller than would be the case with the potential growth in the use of the HFCs.

  12. 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.

  13. Cooling of highly-charged, short-lived ions for precision mass spectrometry at TRIUMF's Ion Trap for Atomic and Nuclear Science

    NASA Astrophysics Data System (ADS)

    Schultz, B. E.; Chowdhury, U.; Simon, V. V.; Andreoiu, C.; Chaudhuri, A.; Gallant, A. T.; Kwiatkowski, A. A.; Macdonald, T. D.; Simon, M. C.; Dilling, J.; Gwinner, G.

    2013-09-01

    At TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN), masses of short-lived nuclides are measured accurately and precisely using Penning trap mass spectrometry. The achievable precision is primarily limited by the radioactive lifetime of the nuclides. To boost the precision TITAN has demonstrated that short-lived isotopes can be charge-bred to higher charge states within 10-100 s of ms using an electron beam ion trap. The charge breeding process increases the energy spread of the ions, which in turn affects the precision and the efficiency. A novel cooler Penning trap (CPET) has been developed to trap and cool highly-charged ions using electrons prior to the precision measurement. A discussion of electron cooling and the current status of CPET will be given.

  14. Development of radioactive ion beam production systems for Tokai Radioactive Ion Acceleration Complex—High temperature ion source for short-lived isotopesa)

    NASA Astrophysics Data System (ADS)

    Otokawa, Y.; Osa, A.; Sato, T. K.; Matsuda, M.; Ichikawa, S.; Jeong, S. C.

    2010-02-01

    We have developed a new ion source system in the isotope separator on-line at Japan Atomic Energy Agency, for separation of short-lived isotopes produced by proton-induced fission of U238. The ion source system is a forced electron beam induced arc discharge version E type ion source with a target container. We successfully operated this system at 2000 °C as a result of reductions in volume of the ion source and the target container, introduction of heating method by electron bombardment, and improvement to the heat shield. This new ion source system was tested using U238 of 640 mg/cm2 with a proton primary beam of 30 MeV, 350 nA. Release times were measured for Kr, In, and Xe. The values of release times are 2.6 s for Kr, 1.8 s for In, and 4.6 s for Xe. In this work, the ion source system enabled us to mass-separate short-lived isotopes such as K93r(T1/2=1.286 s), I129n(T1/2=0.61 s), and X141e(T1/2=1.73 s) with intensity of 103 ions/s.

  15. 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 seawater pH using boron isotopes should be uncompromised by short-term bleaching events. PMID:25396422

  16. 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 seawater pH using boron isotopes should be uncompromised by short-term bleaching events. PMID:25396422

  17. 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.

  18. 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. PMID:9003713

  19. Characterization of short-lived intermediates produced during replication of baculovirus DNA.

    PubMed

    Mikhailov, Victor S; Rohrmann, George F

    2009-10-01

    In this report the short-lived DNA replication intermediates produced in both uninfected and Autographa californica multiple nucleopolyhedrovirus (AcMNPV) infected Spodoptera frugiperda cells were characterized. The methods used included pulse-labeling of DNA in permiabilized cells, treatment of nascent DNA with Mung bean nuclease, and electrophoresis in neutral and alkaline agarose gels. In contrast to uninfected cells that produced a population of small DNA fragments of about 200bp, a population of heterogeneous fragments of up to 5kb with an average size of 1-2kb derived randomly from the virus genome was identified as the short-lived intermediates produced during AcMNPV replication. The intermediates likely include Okazaki fragments derived from the lagging strands in viral replication forks as well as fragments produced during the recombination-dependent replication. PMID:19560496

  20. M-Track: detecting short-lived protein-protein interactions in vivo

    PubMed Central

    Zuzuarregui, Aurora; Kupka, Thomas; Bhatt, Bhumika; Dohnal, Ilse; Mudrak, Ingrid; Friedmann, Christina; Schüchner, Stefan; Frohner, Ingrid E.; Ammerer, Gustav; Ogris, Egon

    2012-01-01

    We developed a protein-proximity assay in yeast based on fusing a histone lysine methyltransferase onto a bait and its substrate onto a prey. Upon binding, the prey is stably methylated and detected by methylation-specific antibodies. We applied this approach to detect varying interaction affinities among proteins in a mitogen-activated protein kinase pathway and to detect short-lived interactions between protein phosphatase 2A and its substrates that have so far escaped direct detection. PMID:22581371

  1. 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.

  2. Miss Piggy, a californium-252 fission fragment source as a generator of short-lived radionuclides

    NASA Astrophysics Data System (ADS)

    Düllmann, Ch. E.; Eichler, B.; Eichler, R.; Gäggeler, H. W.; Jost, D. T.; Kindler, U.; Piguet, D.; Soverna, S.; Thörle, P.; Trautmann, N.; Türler, A.

    2003-10-01

    Carrier-free short-lived nuclides are employed in many different fields of modern nuclear chemistry. The two main production strategies are either thermal neutron-induced fission of 235U or 239Pu at nuclear reactors or spallation neutron sources or charged particle-induced nuclear reactions at accelerator facilities. An alternative method is to use a spontaneously fissioning nuclide. A facility applying this technique ("Miss Piggy") was built at the University of Berne (Switzerland). Californium-252 ( 252Cf), which has a 3% fission branch and a half-life of 2.645 a, is used for the production of short-lived fission products that are stopped in an adjacent recoil chamber. Short-lived nuclides are transported out of the recoil chamber using the well-known gas-jet technique. Over 100 nuclides have been identified so far and used in different applications. Since such a device does not require any large facility and is easy to operate it serves well the needs of typical university laboratories.

  3. CD28–B7 Interaction Modulates Short- and Long-Lived Plasma Cell Function

    PubMed Central

    Njau, Modesta N.; Kim, Jin Hyang; Chappell, Craig P.; Ravindran, Rajesh; Thomas, Leela; Pulendran, Bali; Jacob, Joshy

    2016-01-01

    The interaction of CD28, which is constitutively expressed on T cells, with B7.1/B7.2 expressed on APCs is critical for T cell activation. CD28 is also expressed on murine and human plasma cells but its function on these cells remains unclear. There are two types of plasma cells: short-lived ones that appear in the secondary lymphoid tissue shortly after Ag exposure, and long-lived plasma cells that mainly reside in the bone marrow. We demonstrate that CD28-deficient murine short- and long-lived plasma cells produce significantly higher levels of Abs than do their wild-type counterparts. This was owing to both increased frequencies of plasma cells as well as increased Ab production per plasma cell. Plasma cells also express the ligand for CD28, B7.1, and B7.2. Surprisingly, deficiency of B7.1 and B7.2 in B cells also led to higher Ab levels, analogous to Cd28−/− plasma cells. Collectively, our results suggest that the CD28–B7 interaction operates as a key modulator of plasma cell function. PMID:22908331

  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. 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 interactive adaptable approach offers the possibility to insert the data (objects) into the system directly and on-site. To mitigate the manipulation risk the entry of data (objects) into the main reference (core data) set is granted to a central authorized unit.

  6. 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.

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

    PubMed

    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 (10)C, 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: (12)N (T1/2  =  11 ms) on carbon (9% of (11)C), (29)P (T1/2  =  4.1 s) on phosphorus (20% of (30)P) and (38m)K (T1/2  =  0.92 s) on calcium (113% of (38g)K). 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, (12)N dominates up to 70 s. On bone tissue, (12)N dominates over (15)O 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 (12)N PET counts, we conclude that, for any tissue, (12)N 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 (12)N PET imaging is discussed. PMID:26539812

  8. 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 Yellowstone mats, results suggested that both oxygenic phototroph Synechococcus spp. and the anoxygenic phototroph Roseiflexus spp. use different mechanisms for inorganic carbon fixation at this time of day. These studies illustrate the ability to reveal small changes in isotopic profiles of thousands of peptides from complex mixtures following short-term incubation of labeled substrate of communities in their natural environment. These short-term incubations have the potential for Pro-SIP experiments to capture a relative snapshot in time of community functional activity elucidating which organisms are actively expressing proteins, which pathways are being expressed and how the taxa are acclimated to environmental stimuli during a defined point in time.

  9. Activities Study of Short-lived Radioisotopes with a Filippov-type Plasma Focus

    NASA Astrophysics Data System (ADS)

    Zaeem, Alireza Asle; Mahmood Sadat Kiai, S.; Sedaghatizade, Mahmood; Adlparvar, Shirin; Sheibani, Shahab

    2009-09-01

    Plasma focus devices are characterized by short-lived dense and hot plasma "pinch" due to the radial compression and electromagnetic acceleration. Through a short period of time, typically a few tens of nanoseconds, the pinched plasma goes through two phases of compression (thermal) and expansion (non-thermal or beam target) that provide necessary conditions for high nuclear reaction rates. If appropriate gas admixture at a desirable pressure is used, the processes can generate short-lived radioisotopes (SLRs) which the level of activities depends on the design and operational parameters. In this paper, the results of simulated theoretical works of two SLRs such as 10B (d, n) 11C and 14N (d, n) 15O are presented using a Filippov-type plasma focus "Dena" as a breeder with the bank energy ranges from 20 to 90 kJ at the repetition rates from 1 to 10 Hz. The admixture gas pressure of 10B and 14 N were taken to be approximately 0.05 of initial working pressure at optimum neutron yield regime. The results obtained are discussed.

  10. Using stable isotopes to understand survival strategies of the living fossil, Welwitschia mirabilis

    NASA Astrophysics Data System (ADS)

    Soderberg, K.; Henschel, J.; Macko, S. A.

    2011-12-01

    The Namib Desert along the southwestern coast of Africa is hyper-arid in terms of rainfall (<25 mm/yr), but experiences coastal fog deposition up to 100 days each year. The Namib is also home to the biologically anomalous, very long-lived and evolutionarily ancient gymnosperm Welwitschia mirabilis. Due to its perennial broad green leaves that apparently demand around 1 L of water per day, some have suggested that this living fossil survives on fog deposition. We have investigated this hypothesis using stable isotopes of water (δ18O, δ2H) and found that W. mirabilis shows no evidence of fog uptake. Rather, its stem water looks much like that of large trees that tap into an alluvial aquifer, and nothing like the stem water of shrubs that are endemic to the fog zone and have been shown elsewhere to take up and translocate fog water. We also investigated some biogeochemical aspects of W. mirabilis through δ13C, δ15N and δ34S analysis of stem organic matter. These data revealed a large amount of variability in δ13C and δ15N among plants growing in close proximity to one another, indicating the possibility of micro-environmental control on the C and N cycles. The δ34S data provided a necessary additional constraint on the water isotope investigation.

  11. 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.

  12. 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. PMID:18378157

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

    NASA Astrophysics Data System (ADS)

    Fuglestvedt, Jan S.; Samset, Bjrn 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.

  14. The role of short-lived climate pollutants in meeting temperature goals

    NASA Astrophysics Data System (ADS)

    Bowerman, Niel H. A.; Frame, David J.; Huntingford, Chris; Lowe, Jason A.; Smith, Stephen M.; Allen, Myles R.

    2013-12-01

    Some recent high-profile publications have suggested that immediately reducing emissions of methane, black carbon and other short-lived climate pollutants (SLCPs) may contribute substantially towards the goal of limiting global warming to 2 °C above pre-industrial levels. Although this literature acknowledges that action on long-lived climate pollutants (LLCPs) such as CO2 is also required, it is not always appreciated that SLCP emissions in any given decade only have a significant impact on peak temperature under circumstances in which CO2 emissions are falling. Immediate action on SLCPs might potentially 'buy time' for adaptation by reducing near-term warming; however early SLCP reductions, compared with reductions in a future decade, do not buy time to delay reductions in CO2.

  15. 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.

  16. Quantum non-locality in a two-slit interferometer for short-lived particles

    SciTech Connect

    Klein, Spencer R.; Nystrand, Joakim

    2001-12-01

    We describe a new test of quantum nonlocality, using an interferometer for short-lived particles. The separation is large compared with the particle lifetimes. This interferometer is realized by vector meson production in distant heavy ion collisions. The mesons decay before waves from the two sources (ions) can overlap, so interference is only possible among the decay products. The post-decay wave function must retain amplitudes for all possible decays. The decay products are spatially separated, necessitating a non-local wave function. The interference is measurable by summing the product momenta. Alternately, the products positions could be observed, allowing new tests of the EPR paradox.

  17. 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

  18. 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.

  19. 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

  20. Observation in a discharge of short-lived atomic states by intracavity absorption

    SciTech Connect

    Brink, G.O.; Heider, S.M.

    1981-08-01

    Optical absorption in short-lived excited states of atomic neon caused by dye-laser intracavity absorption has been observed. The states were excited by a microwave discharge in neon gas produced by a microwave cavity located inside the optical cavity of the dye laser. All transitions arising from the 2p manifold of states that are usually seen in emission are here seen in absorption. Best theoretical estimates of the number density of each of the 2p states in the discharge is about 10/sup 5/--10/sup 7//cm/sup 3/, and the mean lifetime of the states is about 19 x 10/sup -9/ sec.

  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. 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

  3. 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

  4. 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.

  5. Short-Lived K2S Molecules in Superionic Potassium Sulfide

    NASA Astrophysics Data System (ADS)

    Tsumuraya, Kazuo; Okeya, Yusuke

    2015-06-01

    First principles molecular dynamics study enables us to elucidate the formation of short-lived K2S molecules in superionic potassium sulfide. Covalent electron densities exist between the ionized immobile sulfurs and their coordinated ionized mobile potassiums forming the respective covalent and the Coulomb bonds between them. Both the bonds induce indirect covalent and indirect Coulomb attractions between the di-interstitial potassiums on the mid-sulfurs forming the molecules. The lifetime of the molecules is 120 fs at 1050 K. The covalent density also exists in short-lived potassium pairs with the lifetime of 110 fs. The three attractions constrain the self-diffusion of the potassiums in the sulfide which reduces Haven's ratios of the potassiums. The absence of the rigid potassium dimers indicates a failure of the chain models for the superionic diffusion. The attractions reduce the Coulomb attractions between them comparing with their completely ionized states which induces the melting of the sublattice of smaller size of the potassiums than the sulfurs: the electronic state of the conductor is intermediate between the ionic crystals and the covalent crystals. The present study classifies the conductors into four types from their electronic states; ionomolecular, ionocovalent, ionometalloid, and ionometallic type superionic conductors.

  6. 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

  7. [Short, medium and long-term follow-up of living donors].

    PubMed

    Oppenheimer Salinas, Federico

    2010-01-01

    Live-donor kidney transplants are being done since more than fifty years ago. In recent years, a marked increase in live donations is observed, as a result of the limited availability of organs from deceased donors. Also, the use of laparoscopic nephrectomy has contributed to increase live donations. A systematic review of the literature shows that short and long-term risks of morbidity and mortality of the donor are reasonably low. Even so, an increased incidence of high blood pressure and mild proteinuria has been reported. On the contrary, no detrimental effect on renal failure is observed and the incidence of long-term chronic renal failure is lower in the donor population when compared with the incidence observed in the general population. In any case, a regular follow-up of the donors is advisable in order to prevent or early detect those medical conditions that would represent a health risk, in particular those conditions that possibly will affect renal function: hypertension, diabetes, proteinuria and obesity. It would be also necessary to establish a nation-wide scientific registry, with prospective regular data collection, that will make possible a more accurate assessment of the long-term risk of uninephrectomy and early detection of new medical information that would contribute to redefine the risk of kidney donation or to establish new requisites in the donor evaluation protocols. PMID:21183969

  8. 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 leachability, partition between soil solid phases (exchangeable Se and Se associated to organic matter) and speciation. At the opposite, the retention strength, solid phase partition and speciation of 77Se(IV) were modified during the experiment time-course and presented different kinetics. 77Se(IV) behavior tended to be similar to the one of ambient Se but still remained less strongly retained and chemically transformed at three months. We concluded that kinetically limited processes are involved in Se retention and transformation in soils and that commonly used short-term experiments (<1 month) do not consider them properly. Otherwise, it seems more judicious to study ambient Se to infer the processes and parameters used in long-term risk assessment modeling. Since three correct and accurate Se isotope ratios were obtained, this new methodology can be further used to simultaneous monitor the reactivity of three different Se forms (e.g., added Se(IV), Se(VI) or Se(0), ambient Se), that will be useful for both soil Se contamination and supplementation contexts.

  9. 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

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

    PubMed Central

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

    2014-01-01

    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

  11. Muscle Senescence in Short-Lived Wild Mammals, the Soricine Shrews Blarina brevicauda and Sorex palustris

    PubMed Central

    HINDLE, ALLYSON G.; LAWLER, JOHN M.; CAMPBELL, KEVIN L.; HORNING, MARKUS

    2015-01-01

    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 (H0: 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: ~50%; B. brevicauda: ~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 (~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

  12. 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.

  13. Telomeres shorten while Tert expression increases during ageing of the short-lived fish Nothobranchius furzeri.

    PubMed

    Hartmann, Nils; Reichwald, Kathrin; Lechel, André; Graf, Michael; Kirschner, Jeanette; Dorn, Alexander; Terzibasi, Eva; Wellner, Juliane; Platzer, Matthias; Rudolph, Karl Lenhard; Cellerino, Alessandro; Englert, Christoph

    2009-05-01

    Age research in vertebrates is often limited by the longevity of available models. The teleost fish Nothobranchius furzeri has an exceptionally short lifespan with 3.5 months for the laboratory strain GRZ and about 6 months for the wild-derived strain MZM-0403. Here we have investigated telomere length in muscle and skin tissue of young and old fish of both strains using different methods. We found age-dependent telomere shortening in the MZM-0403 strain with the longer lifespan, whereas the short-lived GRZ strain showed no significant telomere shortening with advanced age. Sequencing of the two main telomerase genes Tert and Terc revealed that both genes are highly conserved between the N. furzeri strains while there is little conservation to other fish species and humans. Both genes are ubiquitously expressed in N. furzeri and expression levels of Tert and Terc correlate with telomerase activity in a tissue-specific manner. Unexpectedly, the expression level of Tert is increased in aged muscle and skin tissue of MZM-0403 suggesting that telomeres shorten upon ageing despite increased Tert expression and hence high telomerase activity. We further conclude that the extremely short lifespan of the GRZ strain is not caused by diminished telomerase activity or accelerated telomere shortening. PMID:19428446

  14. Implicit short-lived motor representations of space in brain damaged and healthy subjects.

    PubMed

    Rossetti, Y

    1998-09-01

    This article reviews experimental evidence for a specific sensorimotor function which can be dissociated from higher level representations of space. It attempts to delineate this function on the basis of results obtained by psychophysical experiments performed with brain damaged and healthy subjects. Eye and hand movement control exhibit automatic features, such that they are incompatible with conscious control. In addition, they rely on a reference frame different from the one used by conscious perception. Neuropsychological cases provide a strong support for this specific motor representation of space, which can be spared in patients with lesions of primary sensory systems who have lost conscious perception of visual, tactile or proprioceptive stimuli. Observation of these patients also showed that their motor behavior can be "attracted" by a goal only under specific conditions, that is, when the response is immediate and when no cognitive representation of this goal is elaborated at the same time. Beyond the issue of the dissociation between an implicit motor representation and more cognitive processing of spatial information, the issue of the interaction between these two systems is thus a matter of interest. It is suggested that the conscious, cognitive representation of a stimulus can contaminate or override the short-lived motor representation, but no reciprocal influence seem to occur. The interaction observed in patients can also be investigated in normals. The literature provides examples of interaction between sensorimotor and cognitive framing of space, which confirm that immediate action is not mediated by the same system as delayed action, and that elaborating a categorial representation of the action goal prevents the expression of the short-lived sensorimotor representation. It is concluded that action can be controlled by a sensory system which is specialized for on-line processing of relevant goal characteristics. The temporal constraints of this system are such that it can affect the action before a full sensory analysis of this goal has been completed. The performance obtained on the basis of this spatial sensory processing suggests that short-lived motor representations may rather be considered as real "presentation" of the action world, which share its metric properties. PMID:9787059

  15. 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 the north-facing soil profile presents a recent increase of Th leaching that we link to the development of vegetation activity and/or organic matter degradation. In contrast, recent changes within south-facing soil profile affect the deepest part of the active layer, suggesting its deepening as a result of a global warming of Siberian soils.

  16. Evaluation of sediment dynamics in coastal systems via short-lived radioisotopes

    NASA Astrophysics Data System (ADS)

    Giffin, Dan; Corbett, D. Reide

    2003-08-01

    The Neuse and Pamlico River Estuaries are shallow, dynamic systems that have been plagued with symptoms of eutrophication over the past two decades. Extensive research has been conducted over the last 5-10 years to better understand the complex nutrient dynamics of these systems. However, most of these studies have concentrated on nutrient cycling in the water column. Only recently have studies focused on the benthic environment, and most sediment studies have neglected the dynamic nature of the benthos, focusing instead on diffusion as the dominant transport process delivering nutrients to the water column. Although diffusion of nutrients across the sediment-water interface may be important during quiescent periods of sediment deposition and short-term storage, wind events associated with storms throughout the year will resuspend newly deposited sediments resulting in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Sediment resuspension may increase water column nutrient concentrations, and therefore present estimates of nutrient and carbon inputs from the sediments may be too low. This study evaluated short-term sediment dynamics of natural resuspension events and deposition rates in these two estuaries with the use of short-lived radioisotopes, 7Be, 137Cs, and 234Th. Sediment cores at nine sites in the estuaries have been collected at least bimonthly since May 2001. In general, tracers indicate a depositional environment with minimal episodes of removal. The largest sediment removal occurred in August 2001 in the Neuse River where an estimated 2.2 cm of sediment were removed over the previous 6-week period. This removal mechanism essentially advects porewater nutrients into the water column. Calculated advective fluxes of ammonium and phosphate based on this resuspension event were approximately six times greater than the average diffusive flux measured in the same general area of the river. Longer-term deposition rates, using 137Cs, ranged from 1.4 to greater than 5 mm year -1, comparable to earlier studies in the area and agree well with the interpretation of the short-lived tracers. In addition, meteorological (wind speed and direction), turbidity, and bottom current data were collected and indicated that these resuspension events occur when passing fronts developed wind speeds in excess of 4 m s -1 with rapid shifts in direction. Currents exhibited estuarine flow reversals associated with wind events and apparently have some control over the sediment removal processes.

  17. 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

  18. Laser generation of proton beams for the production of short-lived positron emitting radioisotopes

    NASA Astrophysics Data System (ADS)

    Spencer, I.; Ledingham, K. W. D.; Singhal, R. P.; McCanny, T.; McKenna, P.; Clark, E. L.; Krushelnick, K.; Zepf, M.; Beg, F. N.; Tatarakis, M.; Dangor, A. E.; Norreys, P. A.; Clarke, R. J.; Allott, R. M.; Ross, I. N.

    2001-10-01

    Protons of energies up to 37 MeV have been generated when ultra-intense lasers (up to 10 20 W cm -2) interact with hydrogen containing solid targets. These protons can be used to induce nuclear reactions in secondary targets to produce β +-emitting nuclei of relevance to the nuclear medicine community, namely 11C and 13N via (p, n) and (p,α) reactions. Activities of the order of 200 kBq have been measured from a single laser pulse interacting with a thin solid target. The possibility of using ultra-intense lasers to produce commercial amounts of short-lived positron emitting sources for positron emission tomography (PET) is discussed.

  19. Contribution of very short-lived substances to stratospheric bromine loading: uncertainties and constraints

    NASA Astrophysics Data System (ADS)

    Aschmann, J.; Sinnhuber, B.-M.

    2013-02-01

    Very short-lived substances (VSLS) still represent a major factor of uncertainty in the quantification of stratospheric bromine loading. One of the major obstacles for short-lived source gases in contributing to the stratosphere is generally thought to be loss of inorganic bromine (Bry) in the tropical tropopause layer (TTL) due to dehydration. We use sensitivity calculations with a three-dimensional chemistry transport model comprising a consistent parametrization of convective transport and a comprehensive chemistry scheme to investigate the associated processes. The model considers the two most important bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2). The organic bromine source gases as well as the resulting profile of inorganic bromine in the model are consistent with available observations. In contrast to its organic precursors, Bry is assumed to have a significant sorption capacity regarding sedimenting liquid or frozen particles thus the fraction of intact source gases during their ascent through the TTL is a critical factor. We find that source gas injection is the dominant pathway into the stratosphere, about 50% of CHBr3 and 94% of CH2Br2 is able to overcome the cold point tropopause at approximately 17 km altitude, modulated by the interannual variability of the vertical transport efficiency. In fact, our sensitivity calculations indicate that the extent of source gas injection of CHBr3 is highly sensitive to the strength of convection and large-scale ascent; in contrast, modifying the photolysis or the destruction via OH yields a significantly smaller response. In principle, the same applies as well to CH2Br2, though it is considerably less responsive due to its longer lifetime. The next important aspect we identified is that the partitioning of available Bry from short-lived sources is clearly shifted away from HBr, according to our current state of knowledge the only member of the Bry family which is efficiently adsorbed on ice particles. This effect is caused by very efficient heterogeneous reactions on ice surfaces which reduce the HBr/Bry fraction below 15% at the tropical tropopause. Under these circumstances there is no significant loss of Bry due to dehydration in the model, VSLS contribute fully to stratospheric bromine. In addition, we conduct several sensitivity calculations to test the robustness of this result. If heterogeneous chemistry is ignored, the HBr/Bry fraction exceeds 50% and about 10% of bromine from VSLS is scavenged. Dehydration plays a minor role for Bry removal under the assumption that HOBr is efficiently adsorbed on ice as well since the heterogeneous reactions alter the partitioning equilibrium of Bry in favor of HOBr. In this case, up to 12% of bromine from VSLS is removed. Even in the extreme and unrealistic case that adsorbed species on ice particles are instantaneously removed the maximum loss of bromine does not exceed 25%. Assuming 6 parts per trillion by volume (pptv) of bromine short-lived source gases in convective updrafts, a value that is supported by observational data, we find a most likely contribution of VSLS to stratospheric bromine in the range of 4.5-6 pptv.

  20. Contribution of very short-lived substances to stratospheric bromine loading: uncertainties and constraints

    NASA Astrophysics Data System (ADS)

    Aschmann, J.; Sinnhuber, B.-M.

    2012-11-01

    Very short-lived substances (VSLS) still represent a major factor of uncertainty in the quantification of stratospheric bromine loading. One of the major obstacles for short-lived source gases in contributing to the stratosphere is generally thought to be loss of inorganic bromine (Bry) in the tropical tropopause layer (TTL) due to dehydration. We use sensitivity calculations with a~three-dimensional chemistry transport model comprising a consistent parametrization of convective transport and a comprehensive chemistry scheme to investigate the associated processes. The model considers the two most important bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2). The organic bromine source gases as well as the resulting profile of inorganic bromine in the model are consistent with available observations. In contrast to its organic precursors, Bry is assumed to have a~significant sorption capacity regarding sedimenting liquid or frozen particles thus the fraction of intact source gases during their ascent through the TTL is a critical factor. We find that source gas injection is the dominant pathway into the stratosphere, about 50% of CHBr3 and 93% of CH2Br2 is able to overcome the cold point tropopause at approximately 17 km altitude, modulated by the interannual variability of the vertical transport efficiency. In fact, our sensitivity calculations indicate that the extent of source gas injection of CHBr3 is highly sensitive to the strength of convection and large-scale ascent; in contrast, modifying the photolysis or the destruction via OH yields a significantly smaller response. In principal, the same applies as well to CH2Br2, though it is considerably less responsive due to its longer lifetime. The next important aspect we identified is that the partitioning of available Bry from short-lived sources is clearly shifted away from HBr, according to our current state of knowledge the only member of the Bry family which is efficiently adsorbed on ice particles. This effect is caused by very efficient heterogeneous reactions on ice surfaces which reduce the HBr/Bry fraction below 15% at the tropical tropopause. Under these circumstances there is no significant loss of Bry due to dehydration in the model, VSLS contribute fully to stratospheric bromine. In addition, we conduct several sensitivity calculations to test the robustness of this result. If heterogeneous chemistry is ignored, the HBr/Bry fraction exceeds 50% and about 10% of bromine from VSLS is scavenged. Dehydration plays a minor role for Bry removal under the assumption that HOBr is efficiently adsorbed on ice as well since the heterogeneous reactions alter the partitioning equilibrium of Bry in favor of HOBr. In this case, up to 12% of bromine from VSLS is removed. Even in the extreme and unrealistic case that adsorbed species on ice particles are instantaneously removed the maximum loss of bromine does not exceed 25%. In conclusion, considering the average abundance of bromine short-lived source gases in convective updrafts of 6 parts per trillion by volume (pptv) we find a most likely contribution of VSLS to stratospheric bromine in the range of 4.5-6 pptv.

  1. Dynamical Detection of Topological Phase Transitions in Short-Lived Atomic Systems.

    PubMed

    Setiawan, F; Sengupta, K; Spielman, I B; Sau, Jay D

    2015-11-01

    We demonstrate that dynamical probes provide direct means of detecting the topological phase transition (TPT) between conventional and topological phases, which would otherwise be difficult to access because of loss or heating processes. We propose to avoid such heating by rapidly quenching in and out of the short-lived topological phase across the transition that supports gapless excitations. Following the quench, the distribution of excitations in the final conventional phase carries signatures of the TPT. We apply this strategy to study the TPT into a Majorana-carrying topological phase predicted in one-dimensional spin-orbit-coupled Fermi gases with attractive interactions. The resulting spin-resolved momentum distribution, computed by self-consistently solving the time-dependent Bogoliubov-de Gennes equations, exhibits Kibble-Zurek scaling and Stückelberg oscillations characteristic of the TPT. We discuss parameter regimes where the TPT is experimentally accessible. PMID:26588362

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Power-density spectrum of non-stationary short-lived light curves

    NASA Astrophysics Data System (ADS)

    Guidorzi, Cristiano

    2011-08-01

    The power-density spectrum of a light curve is often calculated as the average of a number of spectra derived on individual time intervals the light curve is divided into. This procedure implicitly assumes that each time interval is a different sample function of the same stochastic ergodic process. While this assumption can be applied to many astrophysical sources, there remains a class of transient, highly non-stationary and short-lived events, such as gamma-ray bursts, for which this approach is often inadequate. The power spectrum statistics of a constant signal affected by statistical (Poisson) noise are known to be a χ22 in the Leahy normalization. However, this is no more the case when a non-stationary signal is also present. As a consequence, the uncertainties on the power spectrum cannot be calculated on the basis of the χ22 properties, as assumed by tools such as XRONOS POWSPEC. We generalize the result in the case of a non-stationary signal affected by uncorrelated white noise and show that the new distribution is a non-central χ22(λ), whose non-central value λ is the power spectrum of the deterministic function describing the non-stationary signal. Finally, we test these results in the case of synthetic curves of gamma-ray bursts. We end up with a new formula for calculating the power spectrum uncertainties. This is crucial in the case of non-stationary short-lived processes affected by uncorrelated statistical noise, for which ensemble averaging does not make any physical sense.

  7. 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.

  8. 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

  9. 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

  10. 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 within the first 70cm of the soil layer, either by plant uptake, or adsorption/ precipitation in particular soil layers. Consistently, the Ra isotope ratio in the spring water is similar to the inherited primary soil fraction, suggesting a "deep" (i.e. below the shallow 70cm of soil layer) origin of the exported dissolved radium and the short-scale effect of vegetation cycling onto radium transfer. The radium isotopic ratio in the trees roots does not match the soil exchangeable fraction, nor the seepage waters, but rather the bulk soil, suggesting a large and mixed pool of radium for roots uptake. Decay of 228Ra within the various parts of the trees allows calculating a vegetation cycling duration of about 10 years for this nuclide. Finally an unexpected large amount of unsupported 228Th in the tree leaves can only be explained by a preferential migration of the 228Ac (228Th precursor). The very short life of this nuclide allows therefore assessing that such transport from roots and deposition within stem and leaves take place within 30 hours at the most.

  11. Uncertainties and constraints regarding the contribution of very short-lived substances to stratospheric bromine loading

    NASA Astrophysics Data System (ADS)

    Aschmann, Jan; Sinnhuber, Björn-Martin

    2013-04-01

    A major factor of uncertainty in the assessment of stratospheric bromine loading is the unclear role of very short-lived substances (VSLS). One of the major obstacles for short-lived source gases in contributing to the stratosphere is generally thought to be the loss of inorganic bromine (Bry) in the tropical tropopause layer due to dehydration. Besides the dehydration process itself, transportation pathways and velocities are also of vital importance as they influence the partitioning between mostly insoluble organic source gases and partly soluble inorganic degradation products. To investigate this complex system we employ an extensive set of sensitivity calculations with a three-dimensional chemistry transport model comprising a consistent parameterization of convective transport and a comprehensive chemistry scheme. The model considers the two most important bromine VSLS, bromoform (CHBr3) and dibromomethane (CH2Br2) assuming a fixed and uniform detrainment mixing ratio of 1 pptv each. Despite our simplified approach our model agrees reasonably well with available observations of bromine source and product gases. We find that source gas injection is the dominant pathway for VSLS into the stratosphere; about 50% of CHBr3 and 93% of CH2Br2 is able to overcome the cold point tropopause at approximately 17 km altitude, modulated by the inter-annual variability of the vertical transport efficiency. In fact, our sensitivity calculations indicate that the extent of source gas injection of CHBr3 is highly sensitive to the strength of convection and large-scale ascent; in contrast, modifying the photolysis or the destruction via OH yields a significantly smaller response. The next important aspect we identified is that the partitioning of available Bry from short-lived sources is clearly shifted away from HBr, according to our current state of knowledge the only member of the Bry family which is efficiently adsorbed on ice particles. This effect is caused by very efficient heterogeneous reactions on ice surfaces which reduce the HBr/Bry fraction below 15% at the tropical tropopause. Under these circumstances there is no significant loss of Bry due to dehydration in the model; VSLS contribute fully to stratospheric bromine. In addition, we conduct several sensitivity calculations to test the robustness of this result. The loss of inorganic bromine is not very sensitive to moderate changes of the involved parameters such as the abundance of water vapor, sedimentation velocity of particles or ice uptake coefficients. However, dehydration may play a minor role for Bry removal under the assumption that HOBr is efficiently adsorbed on ice as well since the heterogeneous reactions alter the partitioning equilibrium of Bry in favor of HOBr (up to 12% loss of bromine from VSLS). Even in the extreme and unrealistic case that adsorbed species on ice particles are instantaneously removed the maximum loss of bromine does not exceed 25%.

  12. 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.

  13. 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 investigate full climate responses using coupled chemistry-climate models, and perform regional analyses of specific emission control measures to maximize climate and air quality benefits.

  14. Seasonal variation in the behaviour of a short-lived rodent

    PubMed Central

    2013-01-01

    Background Short lived, iteroparous animals in seasonal environments experience variable social and environmental conditions over their lifetime. Animals can be divided into those with a “young-of-the-year” life history (YY, reproducing and dying in the summer of birth) and an “overwinter” life history (OW, overwintering in a subadult state before reproducing next spring). We investigated how behavioural patterns across the population were affected by season and sex, and whether variation in behaviour reflects the variation in life history patterns of each season. Applications of pace-of-life (POL) theory would suggest that long-lived OW animals are shyer in order to increase survival, and YY are bolder in order to increase reproduction. Therefore, we expected that in winter and spring samples, when only OW can be sampled, the animals should be shyer than in summer and autumn, when both OW and YY animals can be sampled. We studied common vole (Microtus arvalis) populations, which express typical, intra-annual density fluctuation. We captured a total of 492 voles at different months over 3 years and examined boldness and activity level with two standardised behavioural experiments. Results Behavioural variables of the two tests were correlated with each other. Boldness, measured as short latencies in both tests, was extremely high in spring compared to other seasons. Activity level was highest in spring and summer, and higher in males than in females. Conclusion Being bold in laboratory tests may translate into higher risk-taking in nature by being more mobile while seeking out partners or valuable territories. Possible explanations include asset-protection, with OW animals being rather old with low residual reproductive value in spring. Therefore, OW may take higher risks during this season. Offspring born in spring encounter a lower population density and may have higher reproductive value than offspring of later cohorts. A constant connection between life history and animal personality, as suggested by the POL theory, however, was not found. Nevertheless, correlations of traits suggest the existence of animal personalities. In conclusion, complex patterns of population dynamics, seasonal variation in life histories, and variability of behaviour due to asset-protection may cause complex seasonal behavioural dynamics in a population. PMID:24238069

  15. 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 target, but still keeping all components in both baskets.

  16. 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 also found that Fe-60 is produced in small but significant quantities that may be sufficient to explain the observations if the time elapsed delta from the contamination of the ISM to the formation of protoplanetary bodies is not higher than delta = 5 x 10(exp 6) yr. If delta is longer, up to 10 x 10(exp 6) yr, this would require the single AGB star to experience enhanced neutron densities (n(sub n) approximately 3 x 10(exp 9)n/cu cm) in the s-processing zone in order to compensate for the branching at Fe-59. The alternative model of long-term continuous ejection of matter from many AGB stars does not appear to match the observations. We also estimate the Al-26 production from the H-shell and find that the Al-26 abundance in the early solar system may be readily explained in a self-consistent manner. Moreover, Al-26 from AGB stars may contribute substantially to the galactic Al-26 gamma-source, while no significant gamma-flux from Co-60 (deriving from Fe-60 decay) is to be expected.

  17. 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.

  18. Astrophysical Shrapnel: Discriminating among Near-Earth Stellar Explosion Sources of Live Radioactive Isotopes

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    We consider the production and deposition on Earth of isotopes with half-lives in the range 105-108 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 60Fe and 26Al signatures, and extend these estimates to include 244Pu and 53Mn. We discuss interpretations of the 60Fe signals in terrestrial and lunar reservoirs in terms of a nearby stellar ejection ~2.2 Myr ago, showing that (1) the 60Fe yield rules out the TNSN and KN interpretations, (2) the 60Fe 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.

  19. Hydrogen and Oxygen Isotope Data From the AIRMoN Sampling Network, Central and Eastern USA, Suggest a High Degree of Short-Term Isotopic Variability in Precipitation

    NASA Astrophysics Data System (ADS)

    Sjostrom, D. J.; Welker, J. M.

    2005-12-01

    The Atmospheric Integrated Research Monitoring Network (AIRMoN) deposition program consists of an array of precipitation collection stations located throughout the eastern and central United States. At these locations, daily to sub-weekly precipitation sample collection has resulted in an extensive archive of precipitation that allows for analysis on the scale of individual precipitation events. Approximately 500 of these samples collected during 1996-2000 from Florida, Illinois, Ohio, Tennessee, Vermont, and West Virginia have been analyzed for delta D and delta 18 O in order to assess the short-term variability of the isotopic composition of precipitation. The isotopic composition of samples among precipitation events from all locations is highly variable. For example, delta values range by as much as approximately 100 per mil for hydrogen and approximately 12 per mil for oxygen for precipitation events separated by only a few days regardless of geographic location and time of year. There is a weak correlation between temperature at the time of the precipitation event and isotopic value of precipitation at all locations. In general, the long-established trends in isotopic values at different geographic locations are evident in this dataset. For example, on average, the most depleted isotopic values are from locations in the northern and eastern part of the study area, and the most enriched values are from the low latitude sample sites. For individual precipitation events throughout the study area, however, storm source appears to be the primary control of isotopic value rather than temperature. The database that will result from the ongoing isotopic analysis of the complete suite of AIRMoN samples will allow for the examination of both short (daily) and long (decadal) timescale oxygen and hydrogen isotope composition over a wide area of the United States. This dataset will be of benefit to (for example) the study of geographic extent and influence of El Nino/La Nina cycles and other sub-annual to and decadal scale modifications to atmospheric circulation, the back-calculation of storm trajectories, and the temporal variability of climate that may not be evident from traditional climate studies.

  20. 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

  1. Ubiquitin-mediated proteolysis of a short-lived regulatory protein depends on its cellular localization.

    PubMed

    Lenk, U; Sommer, T

    2000-12-15

    In this study we demonstrate that the Deg1 degradation signal of the transcriptional repressor Matalpha2 confers compartment-specific turnover to a reporter protein. Rapid degradation of a Deg1-containing fusion protein is observed only when the reporter is efficiently imported into the nucleus. In contrast, a reporter that is constantly exported from the nucleus exhibits an extended half-life. Furthermore, nuclear import functions are crucial for both Deg1-induced degradation as well as for the turnover of the endogenous Matalpha2 protein. The conjugation of ubiquitin to a Deg1-containing reporter protein is abrogated in mutants affected in nuclear import. Obviously, the Deg1 signal initiates rapid proteolysis within the nucleoplasm, whereas in the cytosol it mediates turnover via a slower pathway. In both pathways the ubiquitin-conjugating enzymes Ubc6p/Ubc7p play a pivotal role. These observations imply that both the cellular targeting of a substrate and the compartment-specific activity of components of the ubiquitin-proteasome system define the half-life of naturally short-lived proteins. PMID:10991948

  2. 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.

  3. 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

  4. A platform for rapid exploration of aging and diseases in a naturally short-lived vertebrate

    PubMed Central

    Harel, Itamar; Benayoun, Bérénice A.; Machado, Ben; Singh, Param Priya; Hu, Chi-Kuo; Pech, Matthew F.; Valenzano, Dario R.; Zhang, Elisa; Sharp, Sabrina C.; Artandi, Steven E.; Brunet, Anne

    2015-01-01

    Summary Aging is a complex process that affects multiple organs. Modeling aging and age-related diseases in the lab is challenging because classical vertebrate models have relatively long lifespans. Here we develop the first platform for rapid exploration of age-dependent traits and diseases in vertebrates, using the naturally short-lived African turquoise killifish. We provide an integrative genomic and genome-editing toolkit in this organism using our de novo-assembled genome and the CRISPR/Cas9 technology. We mutate many genes encompassing the hallmarks of aging, and for a subset, we produce stable lines within 2–3 months. As a proof-of-principle, we show that fish deficient for the protein subunit of telomerase exhibit the fastest onset of telomere-related pathologies among vertebrates. We further demonstrate the feasibility of creating specific genetic variants. This genome-to-phenotype platform represents a unique resource for studying vertebrate aging and disease in a high throughput manner and for investigating candidates arising from human genome-wide studies. PMID:25684364

  5. Observation and modeling of short-lived oxygenated hydrocarbons in the tropical free troposphere

    NASA Astrophysics Data System (ADS)

    Volkamer, Rainer; Apel, Eric

    2013-04-01

    The Tropical Ocean tRoposphere Exchange experiment TORERO (Jan/Feb 2012) probed the influence of air-sea exchange of organic carbon species and very short lived halogen species on the oxidative capacity of the tropical free troposphere over the full tropospheric air column above the eastern tropical Pacific Ocean. Organic carbon is important in the atmosphere, because it influences the reactive chemistry and lifetime of climate active gases (e.g., methane, ozone, dimethyl sulfide), and because of its relevance for the formation, composition and climate impact of aerosols. This presentation summarizes unequivocal evidence for the presence of numerous oxygenated hydrocarbons (i.e., glyoxal, formaldehyde, acetaldehyde, propanal, MVK, MEK, aliphatic aldehydes, alcohols etc.) in the remote marine boundary layer, and in the tropical free troposphere. These species were detected by means of both Differential Optical Absorption Spectroscopy (Airborne MAX-DOAS), and online GC-MS (TOGA) aboard the NSF/NCAR GV aircraft. We employ atmospheric modeling constrained by observations of gas-phase hydrocarbons, aerosols, photolysis frequencies, and meterological parameters measured aboard the plane to elucidate the formation mechanism of this as of yet unaccounted source for oxidized organic carbon, and quantify the influence on the OVOCs on hydroxyl, bromine, chlorine and iodine radical abundances.

  6. Spatial distribution of brominated very short-lived substances in the eastern Pacific

    NASA Astrophysics Data System (ADS)

    Liu, Yina; Yvon-Lewis, Shari A.; Thornton, Daniel C. O.; Campbell, Lisa; Bianchi, Thomas S.

    2013-05-01

    Seawater concentrations and distributions of brominated very short-lived substances (BrVSLS), including bromoform (CHBr3), dibromomethane (CH2Br2), bromodichloromethane (CHBrCl2), chlorodibromomethane (CHClBr2), were measured in the upper water column (5-750 m) in the eastern Pacific. Inorganic nutrient, pigment concentrations, and picoplankton cell counts were measured to determine biogeochemical factors that affect the production and distribution of these BrVSLS. Elevated concentrations of BrVSLS were observed in coastal and tropical seawater. Concentration maxima for CHBr3, CH2Br2, and CHClBr2 were observed below the mixed layer, near the subsurface chlorophyll a maxima, which suggest BrVSLS production may be related to photosynthetic biomass production. Our results also suggest that heterotrophic bacteria may also contribute to CH2Br2 and CHBrCl2 production in the water column. The maximum CHBrCl2 concentration was observed at a depth much deeper than the euphotic zone, which suggests sources other than photosynthetic biomass. Elevated CHBrCl2 concentrations in deeper waters were coincident with elevated CHCl3 concentrations, which may be an evidence for successive chlorine substitution of CHBr3 in deeper and older water masses.

  7. 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

  8. 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.

  9. 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. PMID:17513272

  10. 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

  11. 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.

  12. Saving the Cryosphere in the Arctic and the Himalayas: Mitigation of Short Lived Climate Pollutants

    NASA Astrophysics Data System (ADS)

    Ramanathan, V.

    2012-12-01

    Observations reveal that the polar warming is hastened by the pole ward retreat of the extra-tropical storm track clouds and the sea-ice albedo feedback. The cloud systems associated with the storm tracks are the dominant radiative cooling cloud systems in the planet and their retreat adds more solar energy to the extra-tropical oceans. This is further amplified by the observed reduction in the arctic albedo due to the retreat of the sea-ice. Complicating this situation is the darkening of the arctic cryosphere by black carbon deposition. Over the Himalayas on the other hand, the thermo dynamical feedback involving water vapor amplifies surface warming over the elevated regions of Himalayas-Tibet by factors ranging from1 .5 to 2. This elevated warming is further amplified by black carbon in two distinctly different ways: First absorption of solar radiation in the atmosphere by black carbon has been shown to warm the layers above 5 km by as much as the warming due to CO2. Next, long range transport of black carbon, leads to deposition of black carbon over the bright snow and ice darkens them and enhances the absorption of intense tropical solar radiation over the Himalayas. After summarizing recent observations over the arctic and the Himalayas, we will show how mitigation of the four short lived climate pollutants (methane, black carbon, ozone and HFCs) can significantly slow down the arctic warming and the large warming observed over the elevated regions of the Himalayas-Tibet.

  13. 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

  14. 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.

  15. 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.

  16. 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 be introduced to plants as biologically active molecules such as 11CO2, N13O-3, 18F--[H2O], and H152O . Plants for these studies are grown in controlled-environment chambers at the Phytotron. The chambers offer an array of control for temperature, humidity, atmospheric CO2 concentration, and light intensity. Additionally, the Phytotron houses one large reach-in growth chamber that is dedicated to this project for radioisotope labeling measurements. There are several important properties of short-lived positron-emitting radio-tracers that make them well suited for use in investigating metabolite transport in plants. First, because the molecular mass of a radioisotope-tagged compound is only minutely different from the corresponding stable compound, radiotracer substances should be metabolized and transported in plants the same as their non-radioactive counterparts. Second, because the relatively high energy gamma rays emitted from electron-positron annihilation are attenuated very little by plant tissue, the real-time distribution of a radiotracer can be measured in vivo in plants. Finally, the short radioactive half-lives of these isotopes allow for repeat measurements on the same plant in a short period of time. For example, in studies of short-term environmental changes on plant metabolite dynamics, a single plant can be labeled multiple times to measure its responses to different, environmental conditions. Also, different short-lived radiotracers can be applied to the same plant over a short period of time to investigate the transport and allocation of various metabolites. This newly developed system provides the capabilities for production of 11CO2 at TUNL, transfer of the 11CO 2 gas from the target area at TUNL to a radiation-shielded cryogenic trap at the Phytotron, labeling of photoassimilates with 11C, and in vivo gamma-ray detection for real-time measurements of the radiotracer distribution in small plants. The experimental techniques and instrumentation that enabled the quantitative biological studies reported in this thesis were developed through a series of experiments made at TUNL and the Phytotron. Collimated single detectors and coincidence counting techniques were used to monitor the radiotracer distribution on a coarse spatial scale. Additionally, a prototype Versatile Imager for Positron Emitting Radiotracers (VIPER) was built to provide the capability of measuring radiotracer distributions in plants with high spatial resolution (˜2.5 mm). This device enables detailed quantification of real-time metabolite dynamics on fine spatial scales. The full capabilities of this radiotracer system were utilized in an investigation of the effects of elevated atmospheric CO2 concentration and root nutrient availability on the transport and allocation of recently fixed carbon, including that released from the roots via exudation or respiration, in two grass species. The 11CO2 gas was introduced to a leaf on the plants grown at either ambient or elevated atmospheric CO 2. Two sequential measurements were performed per day on each plant: a control nutrient solution labeling immediately followed by labeling with a 10-fold increase or decrease in nutrient concentration. The real-time distribution of 11C-labeled photoassimilate was measured in vivo throughout the plant and root environment. This measurement resulted in the first observation of a rapid plant response to short-term changes in nutrient availability via correlated changes in the photoassimilate allocation to root exudates. Our data indicated that root exudation was consistently enhanced at lower nutrient concentrations. Also, we found that elevated atmospheric CO2 increased the velocity of photoassimilate transport throughout the plant, enhanced root exudation in an annual crop grass, and reduced root exudation in a perennial native grass.

  17. 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.

  18. 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...

  19. Resveratrol prolongs lifespan and retards the onset of age-related markers in a short-lived vertebrate.

    PubMed

    Valenzano, Dario R; Terzibasi, Eva; Genade, Tyrone; Cattaneo, Antonino; Domenici, Luciano; Cellerino, Alessandro

    2006-02-01

    Resveratrol, a natural phytoalexin found in grapes and red wine, increases longevity in the short-lived invertebrates Caenorhabditis elegans and Drosophila and exerts a variety of biological effects in vertebrates, including protection from ischemia and neurotoxicity. Its effects on vertebrate lifespan were not yet known. The relatively long lifespan of mice, which live at least 2.5 years, is a hurdle for life-long pharmacological trials. Here, the authors used the short-lived seasonal fish Nothobranchius furzeri with a maximum recorded lifespan of 13 weeks in captivity. Short lifespan in this species is not the result of spontaneous or targeted genetic mutations, but a natural trait correlated with the necessity to breed in an ephemeral habitat and tied with accelerated development and expression of ageing biomarkers at a cellular level. Resveratrol was added to the food starting in early adulthood and caused a dose-dependent increase of median and maximum lifespan. In addition, resveratrol delays the age-dependent decay of locomotor activity and cognitive performances and reduces the expression of neurofibrillary degeneration in the brain. These results demonstrate that food supplementation with resveratrol prolongs lifespan and retards the expression of age-dependent traits in a short-lived vertebrate. PMID:16461283

  20. A short-wavelength infrared emitting multimodal probe for non-invasive visualization of phagocyte cell migration in living mice.

    PubMed

    Tsukasaki, Y; Komatsuzaki, A; Mori, Y; Ma, Q; Yoshioka, Y; Jin, T

    2014-11-28

    For the non-invasive visualization of cell migration in deep tissues, we synthesized a short-wavelength infrared (SWIR) emitting multimodal probe that contains PbS/CdS quantum dots, rhodamine 6G and iron oxide nanoparticles. This probe enables multimodal (SWIR fluorescence/magnetic resonance) imaging of phagocyte cell migration in living mice. PMID:25296382

  1. {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.

  2. {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.

  3. 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. PMID:12633999

  4. Transport and Chemistry of Short-Lived Bromocarbons in the Tropics

    NASA Astrophysics Data System (ADS)

    Hossaini, Ryan; Chipperfield, Martyn; Monge-Sanz, Beatriz; Richards, Nigel; Atlas, Elliot; Blake, Donald

    2010-05-01

    We have developed a detailed chemical scheme for the degradation of the short-lived source gases bromoform (CHBr3) and dibromomethane (CH2Br2) and implemented it in the TOMCAT/SLIMCAT three-dimensional (3D) chemical transport model (CTM). The CTM has been used to predict the distribution of the two source gases (SGs) and 11 of their organic product gases (PGs). These first global calculations of the organic PGs show that their abundance is small. The longest lived organic PGs are CBr2O and CHBrO, but their peak tropospheric abundance relative to the surface volume mixing ratio (vmr) of the SGs is less than 5%. We calculate their mean local tropospheric lifetimes in the tropics to be ~7 and ~2 days (due to photolysis), respectively. Therefore, the assumption in previous modelling studies that SG degradation leads immediately to inorganic bromine seems reasonable. We have compared observed tropical SG profiles from a number of aircraft campaigns with various model experiments. In the tropical tropopause layer (TTL) we find that the CTM run using p levels (TOMCAT) and vertical winds from analysed divergence overestimates the abundance of CH2Br2, and to a lesser extent CHBr3, although the data is sparse and comparisons are not conclusive. Better agreement in the TTL is obtained in the sensitivity run using ? levels (SLIMCAT) and vertical motion from diabatic heating rates. Trajectory estimates of residence times in the two model versions show slower vertical transport in the SLIMCAT ?-level version. In the p-level model even when we switch off convection we still find significant amounts of the SGs considered may reach the cold point tropopause; the stratospheric source gas injection (SGI) is only reduced by ~16% for CHBr3 and ~2% for CH2Br2 without convection. Overall, the relative importance of the SG pathway and the PG pathway for transport of bromine to the stratospheric overworld (?>380 K) has been assessed. Assuming a 10-day washout lifetime of Bry in TOMCAT, we find the delivery of total Br from CHBr3 to be 0.72 pptv with ~53% of this coming from SGI. Similary, for CH2Br2 we find a total Br value of 1.69 pptv with ~94% coming from SGI. We infer that these species contribute ~2.4 pptv of inorganic bromine to the lower stratosphere with SGI being the dominant pathway. Slower transport to and through the TTL would decrease this estimate.

  5. Short-lived radionuclide production by non-exploding Wolf-Rayet stars.

    NASA Astrophysics Data System (ADS)

    Arnould, M.; Paulus, G.; Meynet, G.

    1997-05-01

    This paper presents an extension and update of previous calculations of the production by non-exploding Wolf-Rayet stars of radionuclides that could be responsible for certain isotopic anomalies discovered in meteoritic inclusions, or in meteoritic grains of probable circumstellar origin. Quantitative predictions of the time dependence of the radionuclide composition of the wind of Wolf-Rayet stars with initial masses in the wide 25<=M_i_<=120Msun_ range and for metallicities 0.001<=Z<=0.04 are obtained from a set of revised stellar evolution models. Special emphasis is put on the radionuclides with half-lives between about 10^5^ and 10^8^yr that could be produced by neutron captures during central helium burning and ejected during the WC-WO evolutionary phases. We stress that the radionuclide yield predictions are much more secure for Wolf-Rayet stars than for any other potential source of these species that has been contemplated up to now. This relates directly to the simplicity of these stars compared to highly difficult to model objects like Asymptotic Giant Branch stars, novae or supernovae. Our abundance predictions are confronted with existing observational data, or are hoped to help unravelling cases of potential interest for further laboratory quest when observations are lacking. The case of ^26^Al, of special interest for γ-ray line astronomy as well as for cosmochemistry, is also briefly revisited. In contrast to the other considered radionuclides, ^26^Al is produced during hydrogen burning, and is ejected at the WN evolutionary phase of the Wolf-Rayet stars. Our computed yields are also used as the basis for a qualitative discussion of the astrophysical plausibility of the contamination of the protosolar nebula with the radionuclides loading the Wolf-Rayet winds. Our calculations indicate that ^26^Al, ^41^Ca and ^107^Pd can be produced at a level compatible with the observations from a large variety of Wolf-Rayet stars with different masses and initial compositions. Wolf-Rayet stars could also account for the very uncertain limits set on (^36^Cl)_0_ and (^205^Pb)_0_. In addition, ^93^Zr, ^97^Tc, ^99^Tc and ^135^Cs are predicted to be produced in more or less large amounts, but the lack of secure experimental data prevents any meaningful confrontation with the observations. In contrast, the considered stars cannot explain the limits set recently on the amount (^60^Fe)_0_ of ^60^Fe that was live at the start of the condensation sequence in the solar system. Other radionuclides of interest (^53^Mn, ^92^Nb, ^129^I, ^146^Sm, ^182^Hf, ^244^Pu) cannot be produced either during the non-explosive evolution of the Wolf-Rayet stars, but could be synthesized during their eventual supernova explosion.

  6. Genome-wide determination of RNA stability reveals hundreds of short-lived noncoding transcripts in mammals

    PubMed Central

    Tani, Hidenori; Mizutani, Rena; Salam, Kazi Abdus; Tano, Keiko; Ijiri, Kenichi; Wakamatsu, Ai; Isogai, Takao; Suzuki, Yutaka; Akimitsu, Nobuyoshi

    2012-01-01

    Mammalian genomes produce huge numbers of noncoding RNAs (ncRNAs). However, the functions of most ncRNAs are unclear, and novel techniques that can distinguish functional ncRNAs are needed. Studies of mRNAs have revealed that the half-life of each mRNA is closely related to its physiological function, raising the possibility that the RNA stability of an ncRNA reflects its function. In this study, we first determined the half-lives of 11,052 mRNAs and 1418 ncRNAs in HeLa Tet-off (TO) cells by developing a novel genome-wide method, which we named 5′-bromo-uridine immunoprecipitation chase–deep sequencing analysis (BRIC-seq). This method involved pulse-labeling endogenous RNAs with 5′-bromo-uridine and measuring the ongoing decrease in RNA levels over time using multifaceted deep sequencing. By analyzing the relationship between RNA half-lives and functional categories, we found that RNAs with a long half-life (t1/2 ≥ 4 h) contained a significant proportion of ncRNAs, as well as mRNAs involved in housekeeping functions, whereas RNAs with a short half-life (t1/2 < 4 h) included known regulatory ncRNAs and regulatory mRNAs. The stabilities of a significant set of short-lived ncRNAs are regulated by external stimuli, such as retinoic acid treatment. In particular, we identified and characterized several novel long ncRNAs involved in cell proliferation from the group of short-lived ncRNAs. We designated this novel class of ncRNAs with a short half-life as Short-Lived noncoding Transcripts (SLiTs). We propose that the strategy of monitoring RNA half-life will provide a powerful tool for investigating hitherto functionally uncharacterized regulatory RNAs. PMID:22369889

  7. PANTHER Data from SOLVE-II Through CR-AVE: A Contrast Between Long and Short Lived Compounds.

    NASA Astrophysics Data System (ADS)

    Moore, F. L.; Dutton, G. S.; Elkins, J. W.; Hall, B. D.; Hurst, D. F.; Nance, J. D.; Thompson, T. M.

    2006-12-01

    PANTHER (PAN and other Trace Hydrohalocarbons ExpeRiment) is an airborne 6-channel gas chromatograph that measures approximately 20 important atmospheric trace gases whose changing burdens impact air quality, climate change and both stratospheric and tropospheric ozone. In this presentation we will contrast measurements of the long-lived compounds against the short-lived compounds. The long-lived compounds tend to have well-defined troposphere boundary conditions and develop spatial gradients due to stratospheric processing. These measurements have played a major role in quantifying stratospheric transport, stratosphere- troposphere exchange, and ozone loss. In contrast the short-lived species develop spatial and temporal gradients in the tropical tropopause layer (TTL), due to variations in the surface boundary layer concentrations and the coupling of this surface boundary layer to the TTL via convective processes. Deep convection acts like a "conveyor belt" between the source region in the boundary layer and the relatively stable TTL region, often bypassing the free troposphere where scavenging of these short lived species takes place. Loss rates due to reaction with OH and thermal decomposition are reduced in the cold, dry air of the TTL, resulting in longer survival times. Isolation of the TTL region from the free troposphere can last from days to over a month. Significant amounts of these short-lived compound and their byproducts can therefore be transported into the lower stratosphere (LS). Of particular interest are compounds that contain bromine, iodine, and sulfur, not only because of their intrinsic harmful effects in the atmosphere, but also because they have unique source and sink regions that can help to de- convolve transport.

  8. "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…

  9. Melt inclusion shapes: Timekeepers of short-lived giant magma bodies

    NASA Astrophysics Data System (ADS)

    Pamukcu, A. S.; Gualda, G. A. R.; Begue, F.; Gravley, D. M.

    2014-12-01

    Supereruptions have the potential to be devastating events, and constraining the longevity of the giant pools of magma (>450 km3) discharged in such eruptions is critical. Much work has focused on this problem, but no consensus has been reached, and estimates vary considerably depending on the approach used (e.g. Bishop Tuff, zircon geochronology: 103-106 a; oxygen isotopes: 104 a; thermal modeling: 103-105 a; textures, diffusion chronometry: 103 a). This discrepancy exists partly because different timekeepers in eruptive products record different magmatic processes, and methods vary in how well they can resolve timescales related to these processes. We describe a new method using textures (sizes, shapes, positions) of quartz-hosted melt inclusions, determined from propagation phase-contrast x-ray tomography, to estimate crystallization times. The premise of this geochronometer is that, over time, initially round melt inclusions become more faceted through diffusion, and their current shape can be used to estimate their magmatic residence time. This method is distinct in that it illuminates the time that a magma was melt-rich and eruptible rather than crystal-rich and uneruptible; many geochronometers can record these latter, more protracted histories, making it challenging to interpret the timescales that result from them. We also use this method to estimate quartz growth rates, an important but currently poorly constrained quantity. We determine growth rates by relating inclusion residence times and their positions within a crystal: Growth Rate = Length (distance from crystal edge) / Time (residence time). We apply this method to three large-volume high-silica rhyolite eruptions: the paired 240 ka Ohakuri-Mamaku (245 km3 combined volume; central Taupo Volcanic Zone [TVZ], New Zealand), the 26.5 ka Oruanui (530 km3; central TVZ), and the 760 ka Bishop Tuff (1000 km3; California, USA). To validate this method, we compare a subset of our results to those obtained from Ti diffusion profiles in the same crystals. Results show that: (a) the two methods give comparable timescale estimates; (b) quartz growth rates average 10-12 m/s; and (c) quartz melt inclusions give decadal to centennial timescales, revealing that giant magma bodies develop over notably short, historical timescales.

  10. 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).

  11. Longitudinal analysis of Plantago: adaptive benefits of iteroparity in a short-lived, herbaceous perennial

    PubMed Central

    Shefferson, Richard P.; Roach, Deborah A.

    2010-01-01

    Theory suggests that iteroparity may confer greater fitness than semelparity in situations in which temporal environmental variation is high and unpredictable. Variable age-specific mortality, density dependence, and other factors may also favor iteroparity over semelparity. Here, we empirically test the adaptive benefits of greater numbers of reproductive years in a study of reproductive schedules in an experimental population of a short-lived polycarpic perennial, Plantago lanceolata. A large experimental population was established that included four cohorts with similar genetic structure. Individuals were censused for mortality, size, and reproduction for seven years. Plants experienced variable numbers of reproductive years, but one or two years were most common (~46.7% of the population reproduced only once). The probability of flowering at least once prior to death was determined strongly by extrinsic, environmental or intrinsic but environmentally influenced variables, including early-life size, cohort, and block, but also varied with a number of interactions involving paternal lineage. Maternal effects explained small but significant components of the variance in the number of reproductive years among individuals in each cohort, while paternal effects were significant in only two cohorts. Number of reproductive years contributed significantly to fitness in this system, more so than all other variables tested, although most of the variation in relative fitness may be attributed ultimately to environmental influences. We suggest that the high proportion of each cohort composed of plants reproducing only once may be due to environmental constraints on either growth or size. Such environmental influences, particularly on early life size, may result in small but important indirect effects on fitness. PMID:20392009

  12. 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.

  13. The Preparation and Use of Short Half-Lived Radioactive Noble Gases in Nuclear Medicine.

    NASA Astrophysics Data System (ADS)

    Dahl, J. Robert

    1990-01-01

    Radioisotopes of noble gases have been widely used for biomedical studies for many years, in particular for lung function studies and for studies of patients with coronary artery disease. ^{rm 79m}Kr (T_{1over2 } = 50s) emits 130 keV gamma rays in 27% of its disintegrations, ^{rm 127m }Xe (T_{1over2} = 69.2s) emits a 172.5 keV gamma ray in 38% of its disintegrations and a 124.8 keV gamma ray in 69% of its disintegrations and ^{19} Ne (T_{1over2} = 17.1s) decays 99.1% by positron emission. The energy of the ^{rm 79m}Kr gamma ray and of the more abundant ^{ rm 127m}Xe 124.8 keV gamma ray is sufficiently close to the 140.5 keV gamma energy of ^ {rm 99m}Tc to provide images of similar quality using present equipment. Neon-19 offers potential for ventilation studies and regional blood flow measurements using positron emission tomography (PET). The increasing number of small medical cyclotrons provides the alternative of utilizing very short half-lived radioactive noble gases such as ^{rm 79m }Kr, ^{rm 127m} Xe, and ^{19}Ne. A procedure has been developed for preparing these radionuclides by bombarding aqueous solutions of alkali metal halides with 14 MeV protons, using a helium sweep gas to remove the products as they are produced. A target design, production rates, methods of quality control, delivery and use of the ^{rm 79m}Kr and ^{rm 127m}Xe are given. A new method for preparing ^ {19}Ne is presented.

  14. Treatment of solid tumors by interstitial release of recoiling short-lived alpha emitters

    NASA Astrophysics Data System (ADS)

    Arazi, L.; Cooks, T.; Schmidt, M.; Keisari, Y.; Kelson, I.

    2007-08-01

    A new method utilizing alpha particles to treat solid tumors is presented. Tumors are treated with interstitial radioactive sources which continually release short-lived alpha emitting atoms from their surface. The atoms disperse inside the tumor, delivering a high dose through their alpha decays. We implement this scheme using thin wire sources impregnated with 224Ra, which release by recoil 220Rn, 216Po and 212Pb atoms. This work aims to demonstrate the feasibility of our method by measuring the activity patterns of the released radionuclides in experimental tumors. Sources carrying 224Ra activities in the range 10-130 kBq were used in experiments on murine squamous cell carcinoma tumors. These included gamma spectroscopy of the dissected tumors and major organs, Fuji-plate autoradiography of histological tumor sections and tissue damage detection by Hematoxylin-Eosin staining. The measurements focused on 212Pb and 212Bi. The 220Rn/216Po distribution was treated theoretically using a simple diffusion model. A simplified scheme was used to convert measured 212Pb activities to absorbed dose estimates. Both physical and histological measurements confirmed the formation of a 5-7 mm diameter necrotic region receiving a therapeutic alpha-particle dose around the source. The necrotic regions shape closely corresponded to the measured activity patterns. 212Pb was found to leave the tumor through the blood at a rate which decreased with tumor mass. Our results suggest that the proposed method, termed DART (diffusing alpha-emitters radiation therapy), may potentially be useful for the treatment of human patients.

  15. 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.

  16. Polyhalogenated Very Short Live Substances in the Atlantic Ocean, and their Linkages with Ocean Primary Production

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Yvon-Lewis, S. A.; Hu, L.; Bianchi, T. S.; Campbell, L.; Smith, R. W.

    2011-12-01

    The Halocarbon Air-Sea Transect - Atlantic (HalocAST-A) cruise was conducted aboard FS Polarstern during the ANT-XXVII/1 expedition. The ship departed from Bremerhaven, Germany on October 25th and arrived in Cape Town, South Africa on November 24th in 2010. The HalocAST-A cruise was devoted to studying air-sea fluxes of a suite of halocarbon compounds. Atmospheric mixing ratios and seawater concentrations of the halocarbons were continuously measured with the gas chromatograph - mass spectrometer (GC-MS). This study focuses on the polyhalogenated very short lived substances (VSLSs) such as bromoform (CHBr3), dibromomethane (CH2Br2), chlorodibromomethane (CHClBr2), and bromodichloromethane (CHBrCl2). The goal of this study is to examine the distributions of these compounds and possible relationship between their emissions and oceanic primary production. Therefore, along with the halocarbon concentrations, parameters like dissolved organic carbon concentrations, nutrient concentrations, pigment concentrations, and picoplankton and heterotrophic bacteria counts were also determined. The observed saturation anomalies indicated these VSLSs were supersaturated for almost the entire duration of the cruise. The highest seawater concentrations for these compounds were observed near the Canary Islands. Air mixing ratios were also elevated in this region. The net fluxes for CHBr3, CH2Br2, CHClBr2, and CHBrCl2 were 13.8 nmol m-2 d-1, 4.5 nmol m-2 d-1, 4.5 nmol m-2 d-1 and 1.2 nmol m-2 d-1, respectively. During the HalocAST-A cruise, these compounds exhibit similar trends with total chlorophyll a. Contributions from selected phytoplankton group will be further assessed through the use of individual pigment biomarkers.

  17. 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 free-running means that the BC and OC mitigation measures do not necessarily lead to a discernible climate response.

  18. 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 BC and OC mitigation measures do not necessarily lead to a discernible climate response.

  19. 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.

  20. 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

    Trace element concentrations and Nd-Sr-Pb-isotopic ratios of graywackes from the Franciscan subduction complex appear to reflect two geochemically distinct sources. Some of the graywackes show no negative Eu-anomaly (Eu/Eu* >0.9), slightly concave up heavy REE, and generally arc-like trace element patterns. These graywackes have Western Pacific intra-oceanic arc-like Pb-isotopic ratios, probably reflecting derivation from older accreted oceanic arc terranes and supra-subduction zone ophiolites that are common in the Sierra Nevada-Klamath Mountains region. Other graywackes display small but distinctly negative Eu-anomalies (Eu/Eu* <0.9) with Post-Archean Australian Shale (PAAS) like trace element patterns and Pb-isotopic compositions similar to the Sierra Nevada granitic rocks. Although the latter continental arc signature may be expected to typify the younger graywacke samples, there is no systematic separation of these two geochemical groups by age. The two youngest samples fall into the oceanic arc group. In addition, all the graywackes show distinctly gradual light REE depletions from La to Sm when normalized to PAAS. Thus the geochemical characteristics may reflect variation in location of sediment delivery and distributary systems and/or reworking of previously accreted Franciscan materials, rather than progressive unroofing of the Sierra Nevada batholith. Comparison of our data with published data on the forearc basin deposits of the Great Valley Group suggests the same sediment sources. The derivation of trench sediments (subduction complex graywacke) and forearc basin deposits from the same sources precludes a significant exotic source for Franciscan graywackes as proposed in the past by some researchers. The systematic variation of Nd and Sr isotopic composition with age for our Franciscan graywacke samples also mimics the trends of coeval Great Valley Group rocks, in spite of widespread evidence of significant reworking of the detritus which result in 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.

  1. 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.

  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 defined a SLCP mitigation (MIT) scenario. Compared to CLE, the MIT scenario would reduce global methane (CH4) and black carbon (BC) emissions by about 50 and 80 %, respectively. For CH4, measures on shale gas production, waste management and coal mines were most important. For non-CH4 SLCPs, elimination of high-emitting vehicles and wick lamps, as well as reducing emissions from gas flaring, coal and biomass stoves, agricultural waste, solvents and diesel engines were most important. These measures lead to large reductions in calculated surface concentrations of ozone and particulate matter. We estimate that in the EU, the loss of statistical life expectancy due to air pollution was 7.5 months in 2010, which will be reduced to 5.2 months by 2030 in the CLE scenario. The MIT scenario would reduce this value by another 0.9 to 4.3 months. Substantially larger reductions due to the mitigation are found for China (1.8 months) and India (11-12 months). The climate metrics cannot fully quantify the climate response. Therefore, a second research path was taken. Transient climate ensemble simulations with the four ESMs were run for the CLE and MIT scenarios, to determine the climate impacts of the mitigation. In these simulations, the CLE scenario resulted in a surface temperature increase of 0.70 ± 0.14 K between the years 2006 and 2050. For the decade 2041-2050, the warming was reduced by 0.22 ± 0.07 K in the MIT scenario, and this result was in almost exact agreement with the response calculated based on the emission metrics (reduced warming of 0.22 ± 0.09 K). The metrics calculations suggest that non-CH4 SLCPs contribute ~ 22 % to this response and CH4 78 %. This could not be fully confirmed by the transient simulations, which attributed about 90 % of the temperature response to CH4 reductions. Attribution of the observed temperature response to non-CH4 SLCP emission reductions and BC specifically is hampered in the transient simulations by small forcing and co-emitted species of the emission basket chosen. Nevertheless, an important conclusion is that our mitigation basket as a whole would lead to clear benefits for both air quality and climate. The climate response from BC reductions in our study is smaller than reported previously, possibly because our study is one of the first to use fully coupled climate models, where unforced variability and sea ice responses cause relatively strong temperature fluctuations that may counteract (and, thus, mask) the impacts of small emission reductions. The temperature responses to the mitigation were generally stronger over the continents than over the oceans, and with a warming reduction of 0.44 K (0.39-0.49) K the largest over the Arctic. Our calculations suggest particularly beneficial climate responses in southern Europe, where surface warming was reduced by about 0.3 K and precipitation rates were increased by about 15 (6-21) mm yr-1 (more than 4 % of total precipitation) from spring to autumn. Thus, the mitigation could help to alleviate expected future drought and water shortages in the Mediterranean area. We also report other important results of the ECLIPSE project.

  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 defined a SLCP mitigation (MIT) scenario. Compared to CLE, the MIT scenario would reduce global methane (CH4) and black carbon emissions by about 50 and 80%, respectively. For CH4, measures on shale gas production, waste management and coal mines were most important. For non-CH4 SLCPs, elimination of high emitting vehicles and wick lamps, as well as reducing emissions from gas flaring, coal and biomass stoves, agricultural waste, solvents and diesel engines were most important. These measures lead to large reductions in calculated surface concentrations of ozone and particulate matter. We estimate that in the EU the loss of statistical life expectancy due to air pollution was 7.5 months in 2010, which will be reduced to 5.2 months by 2030 in the CLE scenario. The MIT scenario would reduce this value by another 0.9 to 4.3 months. Substantially larger reductions due to the mitigation are found for China (1.8 months) and India (11-12 months). The climate metrics cannot fully quantify the climate response. Therefore, a second research path was taken. Transient climate ensemble simulations with these ESMs were run for the CLE and MIT scenarios, to determine the climate impacts of the mitigation. In these simulations, the CLE scenario resulted in a surface temperature increase of 0.70±0.14 K between the years 2006 and 2050. For the decade 2041-2050, the warming was reduced by 0.22±0.07 K in the MIT scenario, and this result was in almost exact agreement with the response calculated based on the emission metrics (reduced warming of 0.22±0.09 K). The metrics calculations suggest that non-CH4 SLCPs contribute ∼22% to this response and CH4 78%. This could not be fully confirmed by the transient simulations, which attributed about 90% of the temperature response to CH4 reductions. Attribution of the observed temperature response to non-CH4 SLCP emission reductions and black carbon (BC) specifically is hampered in the transient simulations by small forcing and co-emitted species of the emission basket chosen. Nevertheless, an important conclusion is that our mitigation basket as a whole would lead to clear benefits for both air quality and climate. The climate response from BC reductions in our study is smaller than reported previously, largely because our study is one of the first to use fully coupled climate models, where unforced variability and sea-ice responses may counteract the impacts of small emission reductions. The temperature responses to the mitigation were generally stronger over the continents than over the oceans, and with a warming reduction of 0.44 K (0.39-0.49) largest over the Arctic. Our calculations suggest particularly beneficial climate responses in Southern Europe, where the surface warming was reduced by about 0.3 K and precipitation rates were increased by about 15 (6-21) mm yr-1 (more than 4% of total precipitation) from spring to autumn. Thus, the mitigation could help to alleviate expected future drought and water shortages in the Mediterranean area. We also report other important results of the ECLIPSE project.

  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 in the maximal feasible reduction (MFR) scenario, contributing to global mean temperature reduction by about -0.25 oC after 2030. This heating-SLCPs-induced warming mitigation in MFR is, however, largely cancelled out by the temperature increase due to decreases in cooling aerosols (SO42-, NO3-, and organics), resulting in temperature projection which is not quite different from the other scenarios like CLE (current legislation for air quality) or 450ppm climate stabilization (intermediate reduction) scenario. References Bond et al. (2013): Bounding the role of black carbon in the climate system: A scientific assessment, J. Geophys. Res., 118, 5380-5552, doi:10.1002/jgrd.50171, 2013. Cofala et al. (2007): Scenarios of global anthropogenic emissions of air pollutants and methane until 2030, Atmos. Environ., 41, 8486-8499. Kerr et al. (2013): Soot is warming the world even more than thought, Science, 339, 382, doi: 10.1126/science.339.6118.382. Klimont, Z., Brink, C. (2006): Modelling of Emissions of Air Pollutants and Greenhouse Gases from Agricultural Sources in Europe. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria. Shindell et al. (2012): Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security, Science, 335, 183-189, doi: 10.1126/science.1210026.

  6. 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.

  7. 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).

  8. 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 the ramp up emission metrics, the values are generally larger than for pulse or sustained emissions, which holds for all SLCFs. For a potential SLCFs mitigation policy, the dependency of metric values on the region and season of emission should be considered.

  9. Upper limits for the existence of long-lived isotopes of roentgenium in natural gold

    SciTech Connect

    Dellinger, F.; Kutschera, W.; Forstner, O.; Golser, R.; Priller, A.; Steier, P.; Wallner, A.; Winkler, G.

    2011-01-15

    A sensitive search for isotopes of a superheavy element (SHE) in natural gold materials has been performed with accelerator mass spectrometry at the Vienna Environmental Research Accelerator, which is based on a 3-MV tandem accelerator. Because the most likely SHE in gold is roentgenium (Rg, Z = 111), the search concentrated on Rg isotopes. Two different mass regions were explored: (i) For the neutron-deficient isotopes {sup 261}Rg and {sup 265}Rg, abundance limits in gold of 3x10{sup -16} were reached (no events observed). This is in stark contrast to the findings of Marinov et al.[Int. J. Mod. Phys. E 18, 621 (2009)], who reported positive identification of these isotopes with inductively coupled plasma sector field mass spectrometry in the (1-10)x10{sup -10} abundance range. (ii) Theoretical models of SHEs predict a region of increased stability around the proton and neutron shell closures of Z = 114 and N = 184. We therefore investigated eight heavy Rg isotopes, {sup A}Rg, A = 289, 290, 291, 292, 293, 294, 295, and 296. For six isotopes no events were observed, setting limits also in the 10{sup -16} abundance range. For {sup 291}Rg and {sup 294}Rg we observed two and nine events, respectively, which results in an abundance in the 10{sup -15} range. However, pileup of a particularly strong background in these cases makes a positive identification as Rg isotopes--even after pileup correction--unlikely.

  10. 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.

  11. Estimating long-run equilibrium real exchange rates: short-lived shocks with long-lived impacts on Pakistan.

    PubMed

    Zardad, Asma; Mohsin, Asma; Zaman, Khalid

    2013-12-01

    The purpose of this study is to investigate the factors that affect real exchange rate volatility for Pakistan through the co-integration and error correction model over a 30-year time period, i.e. between 1980 and 2010. The study employed the autoregressive conditional heteroskedasticity (ARCH), generalized autoregressive conditional heteroskedasticity (GARCH) and Vector Error Correction model (VECM) to estimate the changes in the volatility of real exchange rate series, while an error correction model was used to determine the short-run dynamics of the system. The study is limited to a few variables i.e., productivity differential (i.e., real GDP per capita relative to main trading partner); terms of trade; trade openness and government expenditures in order to manage robust data. The result indicates that real effective exchange rate (REER) has been volatile around its equilibrium level; while, the speed of adjustment is relatively slow. VECM results confirm long run convergence of real exchange rate towards its equilibrium level. Results from ARCH and GARCH estimation shows that real shocks volatility persists, so that shocks die out rather slowly, and lasting misalignment seems to have occurred. PMID:23853758

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2002-03-01

    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.

  14. 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

  15. 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

  16. Search for short lived neutral particle in the 15.1 MeV isovector transition of 12C

    NASA Astrophysics Data System (ADS)

    Datar, V. M.; Fortier, S.; Gales, S.; Hourani, E.; Langevin, H.; Maison, J. M.; Massolo, C. P.

    1988-01-01

    We report a search for a short lived neutral particle ? emitted in the decay of the 15.1 MeV J?(T)=1+(1) state in 12C. The experiment is sensitive to ?-->e+e- decays and finds no evidence for such a particle. We set upper limits on ??/?? for mean lifetimes between ~10-13 and ~10-8 sec and in the mass range 1.02-2.5 MeV.

  17. 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.

  18. Proline-rich tyrosine kinase-2 is critical for CD8 T-cell short-lived effector fate

    PubMed Central

    Beinke, Sören; Phee, Hyewon; Clingan, Jonathan M.; Schlessinger, Joseph; Matloubian, Mehrdad; Weiss, Arthur

    2010-01-01

    T-cell interactions with antigen-presenting cells are important for CD8 T-cell effector or memory fate determination. The integrin leukocyte function-associated antigen-1 (LFA-1) mediates T-cell adhesion but the contribution of LFA-1–induced signaling pathways to T-cell responses is poorly understood. Here we demonstrate that proline-rich tyrosine kinase-2 (PYK2) deficiency impairs CD8 T-cell activation by synergistic LFA-1 and T-cell receptor stimulation. Furthermore, PYK2 is essential for LFA-1-mediated CD8 T-cell adhesion and LFA-1 costimulation of CD8 T-cell migration. During lymphocytic choriomeningitis virus infection in vivo, PYK2 deficiency results in a specific loss of short-lived effector CD8 T cells but does not affect memory-precursor CD8 T-cell development. Similarly, lack of LFA-1 primarily impairs the generation of short-lived effector cells. Thus, PYK2 facilitates LFA-1–dependent CD8 T-cell responses and promotes CD8 T-cell short-lived effector fate, suggesting that PYK2 may be an interesting therapeutic target to suppress exacerbated CD8 T-cell responses. PMID:20805505

  19. Proline-rich tyrosine kinase-2 is critical for CD8 T-cell short-lived effector fate.

    PubMed

    Beinke, Sören; Phee, Hyewon; Clingan, Jonathan M; Schlessinger, Joseph; Matloubian, Mehrdad; Weiss, Arthur

    2010-09-14

    T-cell interactions with antigen-presenting cells are important for CD8 T-cell effector or memory fate determination. The integrin leukocyte function-associated antigen-1 (LFA-1) mediates T-cell adhesion but the contribution of LFA-1-induced signaling pathways to T-cell responses is poorly understood. Here we demonstrate that proline-rich tyrosine kinase-2 (PYK2) deficiency impairs CD8 T-cell activation by synergistic LFA-1 and T-cell receptor stimulation. Furthermore, PYK2 is essential for LFA-1-mediated CD8 T-cell adhesion and LFA-1 costimulation of CD8 T-cell migration. During lymphocytic choriomeningitis virus infection in vivo, PYK2 deficiency results in a specific loss of short-lived effector CD8 T cells but does not affect memory-precursor CD8 T-cell development. Similarly, lack of LFA-1 primarily impairs the generation of short-lived effector cells. Thus, PYK2 facilitates LFA-1-dependent CD8 T-cell responses and promotes CD8 T-cell short-lived effector fate, suggesting that PYK2 may be an interesting therapeutic target to suppress exacerbated CD8 T-cell responses. PMID:20805505

  20. 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.

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

    NASA Astrophysics Data System (ADS)

    Dillmann, Iris; Abriola, Daniel; Singh, Balraj

    2014-05-01

    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.

  2. 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.

  3. 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…

  4. 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

  5. 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…

  6. Application of the Non-Adiabatic Phase Matrix Method to Vibrational Excitation Near a Short-lived Resonance

    NASA Astrophysics Data System (ADS)

    Morrison, Michael A.; Mazevet, S.; Nesbet, R. K.

    1998-05-01

    Non-adiabatic effects arising from energy exchange between the kinetic energy of the projectile and the nuclear degrees of freedom play a vital role in resonance vibrational excitation of molecules for sufficiently long-lived resonances. The importance of these effects for short-lived resonances is less clear, and the suitability of approximate theories for incorporating these effects to such resonances has been heretofore unknown. We have applied one such approach, the non-adiabatic phase (NADP) matrix method,(R. K. Nesbet, Phys. Rev. A 54), 2899 (1996) to the very short-lived resonance in e--H2 vibrational excitation. Even in this problematic case, the NADP method provides a systematic treatment of the (fixed-nuclei) ^2Σ_u^+ resonance that is consistent for all internuclear separations. We shall compare NADP scattering quantities for excitation of low-lying vibrational states of H2 to benchmark results from body-fixed vibrational close-coupling calculations.(S. J. Buckman, M. J. Brunger, D. S. Newman, G. Snitchler, S. Alston, D. W. Norcross, M. A. Morrison, B. C. Saha, G. Danby, and W. K. Trail, Phys. Rev. Lett. 65), 3253 (1990)

  7. Calpain-generated natural protein fragments as short-lived substrates of the N-end rule pathway

    PubMed Central

    Piatkov, Konstantin I.; Oh, Jang-Hyun; Liu, Yuan; Varshavsky, Alexander

    2014-01-01

    Calpains are Ca2+-dependent intracellular proteases. We show here that calpain-generated natural C-terminal fragments of proteins that include G protein–coupled receptors, transmembrane ion channels, transcriptional regulators, apoptosis controllers, kinases, and phosphatases (Phe-GluN2a, Lys-Ica512, Arg-Ankrd2, Tyr-Grm1, Arg-Atp2b2, Glu-Bak, Arg-Igfbp2, Glu-IκBα, and Arg-c-Fos), are short-lived substrates of the Arg/N-end rule pathway, which targets destabilizing N-terminal residues. We also found that the identity of a fragment’s N-terminal residue can change during evolution, but the residue’s destabilizing activity is virtually always retained, suggesting selection pressures that favor a short half-life of the calpain-generated fragment. It is also shown that a self-cleavage of a calpain can result in an N-end rule substrate. Thus, the autoprocessing of calpains can control them by making active calpains short-lived. These and related results indicate that the Arg/N-end rule pathway mediates the remodeling of oligomeric complexes by eliminating protein fragments that are produced in these complexes through cleavages by calpains or other nonprocessive proteases. We suggest that this capability of the Arg/N-end rule pathway underlies a multitude of its previously known but mechanistically unclear functions. PMID:24550490

  8. 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 supernova, at the end of its normal life. The hypernova explosion, scientists believe, would come only a few million years after the giant star was formed, while it is still within the cloud of gas and dust from which it formed. Neutron stars, on the other hand, are formed by supernova explosions that give a "kick" to the resulting neutron star, propelling it at high speeds. An orbiting pair of neutron stars, astronomers think, would collide only after hundreds of millions of years of orbital decay, by which time they would be far away from the gas and dust of their birthplace. "The observations already have provided crucial insight; we intend to continue observing the relic of the March 29 burst with the VLA, and in the coming months, we will gain new information that will help further refine our ideas about these fireballs," Frail said. "We're going to learn about the size and expansion rate of the fireball and test predictions made by the models." "These observations indicate the extraordinary importance of radio astronomy for providing information that can be gained in no other way about one of the major frontier areas of astrophysics," said Hugh Van Horn, Director of the NSF's Division of Astronomical Sciences. The March 29 burst (GRB 980329) was the second such blast to have its afterglow detected at radio wavelengths. Last year, the VLA made the first radio detection of a GRB afterglow, finding radio emission coming from the location of a Gamma Ray Burst on May 8, 1997 (GRB 970508). "Of the world's radio telescopes, only the VLA has the sensitivity and resolving power to quickly detect these radio afterglows of Gamma Ray Bursts and study them in detail over extended periods of time," Taylor said. "Even so, we only see the brightest one-third of them. With upgraded capabilities at the VLA, as planned by NRAO, we will see them all." The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  9. 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.

  10. 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

  11. 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

  12. Excited states of tryptophan in cod parvalbumin. Identification of a short-lived emitting triplet state at room temperature.

    PubMed Central

    Sudhakar, K; Phillips, C M; Williams, S A; Vanderkooi, J M

    1993-01-01

    The fluorescence and phosphorescence spectra of model indole compounds and of cod parvalbumin III, a protein containing a single tryptophan and no tyrosine, were examined in the time scale ranging from subnanoseconds to milliseconds at 25 degrees C in aqueous buffer. For both Ca- bound and Ca-free parvalbumin and for model indole compounds that contained a proton donor, a phosphorescent species emitting at 450 nm with a lifetime of approximately 20-40 ns could be identified. A longer-lived phosphorescence is also apparent; it has approximately the same absorption and emission spectrum as the short-lived triplet molecule. For Ca parvalbumin, the decay of the long-lived triplet tryptophan is roughly exponential with a lifetime of 4.7 ms at 25 degrees C whereas for N-acetyltryptophanamide in aqueous buffer the decay lifetime was 30 microseconds. In contrast, the lifetime of the long-lived tryptophan species is much shorter in the Ca-free protein compared with Ca parvalbumin, and the decay shows complex nonexponential kinetics over the entire time range from 100 ns to 1 ms. It is concluded that the photochemistry of tryptophan must take into account the existence of two excited triplet species and that there are quenching moieties within the protein matrix that decrease the phosphorescence yield in a dynamic manner for the Ca-depleted parvalbumin. In contrast, for Ca parvalbumin, the tryptophan site is rigid on the time scale of milliseconds. PMID:8324187

  13. 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.

  14. 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 exposed to radon progeny by measuring their concentrations, aerosol sizes, and unattached fractions. PMID:24831865

  15. Harvard-MIT research program in short-lived radiopharmaceuticals. Progress report, March 1, 1983-February 29, 1984

    SciTech Connect

    Adelstein, S.J.; Brownell, G.L.

    1984-02-01

    This report describes research efforts towards the achievement of a clearer understanding of the solution chemistry of technetium in order to facilitate the design of future clinical agents labeled with Tc-99m, the development of new receptor binding radiopharmaceuticals for the in vivo assessment of insulin receptors and for imaging the adrenal medulla and the brain, the examination of the utility of monoclonal antibodies and liposomes in the design of radiopharmaceuticals for diagnosis and therapy, and the synthesis of short-lived positron-emitting radiopharmaceuticals for transverse imaging of regional physiological processes.

  16. A rapid method for preparing undecalcified sections of bone for autoradiographic investigation with short-lived radionuclides

    SciTech Connect

    Savelkoul, T.J.; Visser, W.J.; Roelofs, J.M.; Lentferink, M.H.

    1983-01-01

    To prepare sections of undecalcified bone suitable both for autoradiography with short-lived radionuclides such as /sup 99m/Tc (t 1/2 . 6 hr) and for normal histology, rapid processing is necessary. By modifying the routine technique of embedding in plastic, sections can be obtained within 6 hours. The most important modification concerns the temperature used for the different steps in the process. The procedure has been used to localize /sup 99m/Tc labeled methylene diphosphonate for skeletal scintigraphy.

  17. Nuclear photoactivation cross sections for short-lived isomeric states excited with a 6 MeV linac

    NASA Astrophysics Data System (ADS)

    Anderson, J. A.; Eberhard, C. D.; Byrd, M. J.; Carroll, J. J.; Collins, C. B.; Scarbrough, E. C.; Antich, P. P.

    1989-04-01

    Photoactivation cross sections for short-lived (T {1}/{2} < 20 s) isomeric states in 167Er, 79Br, 191Ir, 183W, 197Au, 77Se, 137Ba and 89Y were determined using bremsstrahlung from a 6 MeV medical therapy linac. A portable NaI(Tl) spectrometer and pneumatic transfer system was designed to avoid impacting normal use of the linac. Comparison with data obtained at the PITHON flash X-ray source (1.5 MeV endpoint energy) indicates that cross sections for populating these isomers through gateway states in the range 1.5-6 MeV are more than three orders of magnitude greater than corresponding cross sections below 1.5 MeV. The results are significant for the development of photoactivation techniques to measure short (<100 ns), nonreproducible bremsstrahlung pulses.

  18. Effects of Soy-derived diets on plasma and liver lipids, glucose tolerance, and longevity in normal, long-lived and short-lived mice.

    PubMed

    Bartke, A; Peluso, M R; Moretz, N; Wright, C; Bonkowski, M; Winters, T A; Shanahan, M F; Kopchick, J J; Banz, W J

    2004-08-01

    We examined the effects of diets based on a low isoflavone or a high isoflavone soy protein isolates in normal, growth-hormone receptor knockout and Ames dwarf, and Prop 1 (df) mice that are hypoinsulinemic, insulin-sensitive, and exceptionally long-lived, as well as in growth hormone transgenic mice that are hyperinsulinemic, insulin-resistant, dyslipidemic, and short-lived. Soybean diets tended to normalize plasma cholesterol levels in dwarf and transgenic mice, while low isoflavone diet reduced plasma triglycerides in most of the examined genotypes. The effects of low isoflavone and high isoflavone diets on the levels of free and esterified cholesterol in the liver were strongly genotype-dependent. Fasting blood glucose levels were reduced and glucose tolerance improved by both low isoflavone and high isoflavone diets in growth hormone-transgenic mice and in their normal siblings. Glucose tolerance was also improved by high-isoflavone diet in growth hormone receptor knockout mice. Lifespan was increased by low isoflavone diet in normal mice from two of the examined stocks. High isoflavone diet increased lifespan in normal animals from one line, but reduced lifespan of normal mice from a different line. We conclude that dietary soy protein intake can improve plasma and hepatic lipid profiles, reduce fasting glucose, enhance capacity for glucose tolerance, and prolong life, but all of these effects are strongly genotype-dependent. PMID:15326565

  19. Validation of Six Short and Ultra-short Screening Instruments for Depression for People Living with HIV in Ontario: Results from the Ontario HIV Treatment Network Cohort Study

    PubMed Central

    Choi, Stephanie K. Y.; Boyle, Eleanor; Burchell, Ann N.; Gardner, Sandra; Collins, Evan; Grootendorst, Paul; Rourke, Sean B.

    2015-01-01

    Objective Major depression affects up to half of people living with HIV. However, among HIV-positive patients, depression goes unrecognized 60–70% of the time in non-psychiatric settings. We sought to evaluate three screening instruments and their short forms to facilitate the recognition of current depression in HIV-positive patients attending HIV specialty care clinics in Ontario. Methods A multi-centre validation study was conducted in Ontario to examine the validity and accuracy of three instruments (the Center for Epidemiologic Depression Scale [CESD20], the Kessler Psychological Distress Scale [K10], and the Patient Health Questionnaire depression scale [PHQ9]) and their short forms (CESD10, K6, and PHQ2) in diagnosing current major depression among 190 HIV-positive patients in Ontario. Results from the three instruments and their short forms were compared to results from the gold standard measured by Mini International Neuropsychiatric Interview (the “M.I.N.I.”). Results Overall, the three instruments identified depression with excellent accuracy and validity (area under the curve [AUC]>0.9) and good reliability (Kappa statistics: 0.71–0.79; Cronbach’s alpha: 0.87–0.93). We did not find that the AUCs differed in instrument pairs (p-value>0.09), or between the instruments and their short forms (p-value>0.3). Except for the PHQ2, the instruments showed good-to-excellent sensitivity (0.86–1.0) and specificity (0.81–0.87), excellent negative predictive value (>0.90), and moderate positive predictive value (0.49–0.58) at their optimal cut-points. Conclusion Among people in HIV care in Ontario, Canada, the three instruments and their short forms performed equally well and accurately. When further in-depth assessments become available, shorter instruments might find greater clinical acceptance. This could lead to clinical benefits in fast-paced speciality HIV care settings and better management of depression in HIV-positive patients. PMID:26566285

  20. β-decay half-lives of new neutron-rich isotopes 167,168Tb and levels in 167,168Dy

    NASA Astrophysics Data System (ADS)

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

    1999-06-01

    β-decay half-lives of new neutron-rich isotopes 167Tb and 168Tb produced in the 20 MeV proton-induced fission of 238U have been determined to be 19.4(27) s and 8.2(13) s, respectively, using a gas-jet coupled on-line isotope separator. The present half-lives and those of the recently identified nuclei 159Pm, 161Sm, 165Gd, 166Tb were compared with theoretical predictions. The recent calculation by the gross theory with the new one-particle strength functions shows quite good agreement with the experimental half-lives. Excited states of the daughter nuclides 167Dy and 168Dy have been established for the first time. Level energies of the first 2+ states in even-even Dy isotopes were found to show an irregular behavior at 164Dy and increasing deformation toward the neutron midshell around N~104.

  1. 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.

  2. Production of Short-lived Radionuclides by Protons and Neutrons in Fe and Ni Targets: Cross Sections Needed for Cosmic Ray Studies

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Vincent, J.; Jones, D. T. L.; Binns, P. J.; Langen, K.; Schroeder, I.; Buthelezi, Z.; Brooks, F. D.; Buffler, A.; Allie, M. S.

    2000-01-01

    New neutron and proton cross sections for short-lived radionuclides produced in Fe and Ni are presented. These cross sections are essential to understand cosmic ray interactions with meteorites and the lunar surface.

  3. 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

  4. 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.

  5. Structure effects in the calculation of beta strength functions and half lives of Rb and Br isotopes

    SciTech Connect

    Rab, S.; Shihab-Eldin, A.

    1987-12-10

    The properties of beda delayed neutron emission of the precursors around mass 95 are investigated using spherical Shell Model plus pairing. The objective of this work is to find out the important parameters that effect these properties. The strength functions and half lives of both even and odd Rb and Br precursors are calculated in BCS quasi-particle theory as well as in Seniority Truncated Exact Diagonalization (STED) scheme. The calculated half lives from the two schemes are in close agreement with each other. STED gave much smoother overall trend which is in better agreement with experimental values. The calculations reveal that the so called 'odd decays' which depend in an essential way on the parent ground state configuration are of crucial importance in determining both half life, t/sub 1/2/ and delayed neutron emission probability, P/sub n/. Furthermore, it is shown that it is not possible to choose apriori global set for the single particle Shell model basis to predict the correct ground state configurations for both the odd and even nuclei. Instead, it is necessary to examine available experimental evidence in order to construct a more valid global set for single particle basis. The significant variations of the predicted half lives according to the different parent ground-state configuration choices, reveal the importance of nuclear structure effects in these isotopes. The calculated t/sub 1/2/ and P/sub n/ of Rb and Br precursors are presented, discussed and compared with experimental values.

  6. Energy Levels and Half-Lives of Gallium Isotopes Obtained by Photo-Nuclear Reaction

    NASA Astrophysics Data System (ADS)

    Dulger, F.; Akkoyun, S.; Bayram, T.; Dapo, H.; Boztosun, I.

    2015-04-01

    We have run an experiment to determine the energy levels and half-lives of Gallium nucleus by using the photonuclear reactions with end-point energy of 18 MeV bremsstrahlung photons, produced by a clinical linear accelerator. As a result of 71Ga(y,n)70Ga and 69Ga(Y,n)68Ga photonuclear reactions, the energy levels and half-lives of 70Ga and 68Ga nuclei have been determined. The results are in good agreement with the literature values.

  7. 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.

  8. Fast Optical Photometry of Galaxies: Observations of Short-Lived Flare Events

    NASA Astrophysics Data System (ADS)

    Zhilyaev, B. E.; Romanyuk, Ya. O.; Verlyuk, I. A.; Svyatogorov, O. A.; Petrov, M. I.; Lovkaya, M. N.

    2006-12-01

    We have monitored two bright galaxies, M 85 and NGC 7331, on timescales as short as 0.01 s. In the optical, we discovered an unusual burst coincident with the galaxy M 85. We registered a sudden onset with a characteristic time of less than 10 ms with subsequent quasi-exponential decay within approximately 1 s and an amplitude of 2.5 mag in the V band. In the course of high-speed monitoring with two Crimean telescopes operated synchronously, in both independent instruments we have registered one coincident event occurring in NGC 7331 with a duration of ˜ 0.6 s. The amplitudes range from ˜ 3 mag to ˜ 0.3 mag in the U and I bands, respectively. Merging of an intermediate-mass black hole with a small black hole or normal star seems to be the most plausible mechanism responsible for short bursts. Our observations support the hypothesis concerning the existence of intermediate-mass black holes in the centers of galaxies and in dense globular clusters.

  9. Spatial and Time Coincidence Detection of the Decay Chain of Short-Lived Radioactive Nuclei

    SciTech Connect

    Granja, Carlos; Jakubek, Jan; Platkevic, Michal; Pospisil, Stanislav

    2010-08-04

    The quantum counting position sensitive pixel detector Timepix with per-pixel energy and time resolution enables to detect radioactive ions and register the consecutive decay chain by simultaneous position-and time-correlation. This spatial and timing coincidence technique in the same sensor is demonstrated by the registration of the decay chain {sup 8}He{yields}{sup {beta} 8}Li and {sup 8}Li{yields}{sup {beta}-} {sup 8}Be{yields}{alpha}+{alpha} and by the measurement of the {beta} decay half-lives. Radioactive ions, selectively obtained from the Lohengrin fission fragment spectrometer installed at the High Flux Reactor of the ILL Grenoble, are delivered to the Timepix silicon sensor where decays of the implanted ions and daughter nuclei are registered and visualized. We measure decay lifetimes in the range {>=}{mu}s with precision limited just by counting statistics.

  10. Spatial and Time Coincidence Detection of the Decay Chain of Short-Lived Radioactive Nuclei

    NASA Astrophysics Data System (ADS)

    Granja, Carlos; Jakubek, Jan; Köster, Ulli; Platkevic, Michal; Pospisil, Stanislav

    2010-08-01

    The quantum counting position sensitive pixel detector Timepix with per-pixel energy and time resolution enables to detect radioactive ions and register the consecutive decay chain by simultaneous position-and time-correlation. This spatial and timing coincidence technique in the same sensor is demonstrated by the registration of the decay chain 8He-->β 8Li and 8Li-->β- 8Be-->α+α and by the measurement of the β decay half-lives. Radioactive ions, selectively obtained from the Lohengrin fission fragment spectrometer installed at the High Flux Reactor of the ILL Grenoble, are delivered to the Timepix silicon sensor where decays of the implanted ions and daughter nuclei are registered and visualized. We measure decay lifetimes in the range >= μs with precision limited just by counting statistics.

  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. PMID:25795492

  13. 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

  14. Validation of normal and pathologic right ventricular function using ultra-short-lived Krypton-81m

    SciTech Connect

    Nienaber, C.; Spielmann, R.; Wasmus, B.; Mathey, D.; Montz, R.; Bleifield, W.

    1984-01-01

    Measurement of right ventricular ejection fraction (RVEF) using conventional count-based, non-geometry dependent first-pass radionuclide techniques and technetium labelled compounds (T/2 = 6 hours) implies unnecessary whole body radiation and repeated injections of isotope for sequential RVEF estimate. Kr-81m (T/2 = 13 secs) continuously eluted in 5% glucose from a bed-side rubidium-81 generator is intravenously infused providing high count density and high photon flux for rapid imaging of the right-side chambers in ECG-gated equilibrium acquisition mode. A variable right anterior oblique projection is adjusted for optimal right atrio-ventricular separation. Left-sided heart and lung background is minimized by rapid decay and efficient exhalation of Kr-81m, requiring no algorithm for background correction. RV septal and free wall contours are aligned by a semiautomatic edge detection program; tricuspid and pulmonary valve planes are defined from phase images using variable ROIs to compensate for systolic valve plane motion. To cover a wide range of RVEF (13%-63%) both methods were compared in 10 normals, 11 patients (pts) with pulmonary hypertension (PH), 4 pts with RV outflow tract obstruction (RVOT-OB) and 4 pts with RV infarction (RV-MI) at rest (R) and during dynamic exercise (E). The paper concludes that equilibrium RV imaging using Kr-81m is an accurate and reproducible method with potential for serial assessment of RVEF in a variety of RV abnormalities both at R and during E. Advantages of this method include: extremely low radiation to patients, high photon flux for rapid imaging and clear atrio-ventricular separation without background.

  15. Linking early Earth magma ocean crystallization and overturn with observed large low-shear-velocity provinces (LLSVPs) and short-lived radioisotopic measurements in Archean rocks

    NASA Astrophysics Data System (ADS)

    Brown, S. M.; Elkins-Tanton, L. T.; Walker, R. J.

    2013-12-01

    Motivated by the well-characterized discrepancy between measurements of 142Nd in chondrites and those in Earth rocks (e.g.,[1][2]) in addition to recent measurements of Archean rocks with anomalous 142Nd and 182W (e.g.,[3][4][5]), we model the crystallization and overturn of a terrestrial chondritic magma ocean, and track the isotopic reservoirs that may result. Following magma ocean solidification, solid-state overturn occurs because solidification produces a gravitationally unstable configuration where the last cumulates to solidify are densest and also enriched in incompatible elements. As suggested by [1][2], these originally shallow cumulates that, following overturn, would now reside near the core-mantle boundary are tantalizing targets for the hypothesized hidden reservoir(s) of incompatible elements. These last, dense, enriched cumulates may have evolved negative 142Nd and 182W isotopic anomalies, while cumulates that form earlier and deeper in the magma ocean would likely be poor in incompatible elements and have evolved complementary positive isotopic anomalies. Because crystal - liquid partition coefficients of Sm, Nd, Hf, and W in nucleating mantle phases are poorly constrained and vary over orders of magnitude, we use a Monte Carlo approach to cover the parameter space of reported partition coefficients. Although data are limited, Archean rocks appear to show a non-linear trend between age and 142Nd and 182W, suggesting inefficient heterogeneous mixing of some of the early enriched reservoir (EER or late stage cumulates) back into the early depleted reservoir (EDR or deeper cumulates) during or after overturn, also first suggested by [1][2]. To account for this, we model various mixing scenarios using post-overturn mantle stratigraphy. Additionally, because 142Nd and 182W are decay products of short-lived radioisotopes, the timing of magma ocean crystallization is critical to producing a modern day mantle consistent with measured compositions. We therefore iterate through time to determine the statistically most likely time of the last major mantle-melting event. Consistent with [2], we argue that the EER is not hidden but is instead the seismologically observed large low-shear-velocity provinces (LLSVPs), or the D'' region, and the ultra low velocity zones (ULVZs) are dense, iron-rich silicon-poor melts of the LLSVPs. Given this, the isotopic reservoirs produced by our models must mix such that the EER remaining after mixing is the same volume as the LLSVPs, or 2% of the mantle (e.g., [6][7]). Approximately two-thirds our run results are "successful" given known partition coefficients, and so our results suggest that this model is viable: magma ocean fractional solidification can produce mantle reservoirs consistent with isotopic compositions observed in some rocks, and can produce a dense lower mantle layer consistent in longevity and volume to the LLSVPs. [1]Boyet and Carlson,2005,Science,309(5743),576-81.[2]Carlson and Boyet,2008,Phil. Trans. R. Soc. A,366(1883),4077-103. [3]Willbold et al.,2011,Nature,477(7363), 195-8. [4]Touboul et al.,2012,Science,335(6072),1065-9. [5]Rizo et al.,Nature,491(7422),96-100. [6]Burke et al.,2008,EPSL,265(1-2),49-60. [7]Hernlund and Houser,2008,EPSL,265(3-4),423-37.

  16. 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.

  17. 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 utilizes an upwelling diffusion energy balance model and focuses on the thermosteric part of sea-level rise. Example GSP results are 244, 15 and 278 for BC, CH4 and N2O for a time horizon of 100 years. Compare GWP and GTP values of 405, 24 and 288 as well as 62, 4.5 and 252. The main result of the study is that no climate forcer is in any absolute sense short lived when it comes to Sea Level impacts. All of the examined climate forcers have considerable influence on the thermosteric SLR, and the closely linked ocean heat content, on the time scale of centuries. The reason for this is that heat, once it has been induced by the climate drivers and warmed the surface ocean, is transported down into the slowly mixing oceans. References: Shindell, D. et al. Simultaneously mitigating near-term climate change and improving human health and food security. Science 335, 183-189 (2012). Bond, T. C. et al. Bounding the role of black carbon in the climate system: A scientific assessment. Journal of Geophysical Research: Atmospheres 118 5380-5552 (2013). Hu, A., Xu, Y., Tebaldi, C., Washington, W. M. & Ramanathan, V. Mitigation of short-lived climate pollutants slows sea-level rise. Nature Climate Change 3, 730-734 (2013).

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

    PubMed Central

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

    2011-01-01

    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

  19. 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 usefulness of collecting tritium data in streamwater to document short-term variations in the older component of the TT distribution. Our results also shed light on the complex relationships between stored water and water in transit, which are highly non-linear and remain poorly understood.

  20. 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 component of the TT distribution. Our results also shed light on the complex relationships between stored water and water in transit, which are highly nonlinear and remain poorly understood.

  1. Plasma motions in a short-lived filament related to a magnetic flux cancellation

    NASA Astrophysics Data System (ADS)

    Zuccarello, F.; Battiato, V.; Contarino, L.; Romano, P.; Spadaro, D.

    2007-06-01

    Context: In recent years the mechanisms responsible for filament formation and evolution have been investigated by many authors. In particular, the role played by the processes of magnetic flux cancellation in building up or destroying filaments is still a matter of debate. Aims: In this paper we analyze the evolution of an active region filament that formed in NOAA 10 407 on 14 July 2003, to investigate the phenomena responsible for its destabilization and short lifetime (~12 h). Methods: This analysis is based on high-resolution Hα data acquired by THEMIS operating in IPM mode, on Hα data acquired at Big Bear Solar Observatory, and on MDI/SOHO magnetograms. Using these data, we determined the morphological, dynamical, and magnetic evolution of the filament. Results: The chromospheric images show two dark surges occurring sequentially in the northern part of the filament, besides two bright Hα patches located in the same area; from analysis of the photospheric magnetograms, we could infer that a magnetic flux cancellation had occurred in this area. Conclusions: The presence of a cancelling magnetic feature (CMF) in the same area where the dark Hα surges occurred, the temporal behavior of the velocity fields in the surges, and the presence of bright Hα patches in the CMF area, suggest a scenario where the coronal arcade initially sustaining the filament might have undergone consecutive reconnection processes. From the concurrence of these events with the filament activation and successive disappearance, we believe that the arcade field lines, after the reconnection events, changed such that the plasma filament was no longer confined in the arcade: this led to its destabilization and disappearance.

  2. 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

  3. Optical detection of ESR spectra of short-lived ion-radical pairs produced in solution by ionizing radiation

    SciTech Connect

    Molin, Y.N.; Anisimov, O.A.; Grigoryants, V.M.; Molchanov, V.K.; Salikhov, K.M.

    1980-07-10

    A new and very sensitive technique to detect ESR spectra of short-lived radical pairs in solution is proposed on the basis of optical detection of magnetic resonance (ODMR). An ODMR spectrometer has been constructed for detecting ESR spectra of ion-radical pairs created by ionizing radiation. The singlet ESR signal from (naphthalene)-/(naphthalene)/sup +/ pairs has been observed in a naphthalene solution in squalene at an average concentration of 20 radical pairs per sample with a signal-to-noise ratio equal to 10/1. The hyperfine structure has been resolved in the ESR spectrum of (diphenyl)-/(diphenyl)/sup +/ pairs at a low diphenyl concentration in squalane and spectrum narrowing due to charge-transfer reaction has been observed at a high diphenyl concentration.

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

    PubMed

    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 Ca(2+) influx through ruthenium red- and SKF 96365-sensitive Ca(2+)-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

  5. Photo-Induced Assembly of Nanostructures Triggered by Short-Lived Proton Transfers in the Excited-State.

    PubMed

    Cardenas-Daw, Carlos; Gröhn, Franziska

    2015-07-15

    Light stimulation was used to trigger the assembly of nanostructures by directly powering changes at the supramolecular level without incurring net chemical changes at the molecular level. Polyethylene imine, a polybase, was mixed in aqueous solution with sodium 1-naphthol-4-sulfonate, an aromatic alcohol, which, in the electronic excited-state, undergoes a short-lived increase in acidity. Excited-state proton transfers between these components were induced by photoexcitation, which led to the formation of hydrogen bonds in the ground-state. Ionic forces, π-π stacking, and hydrophobic effect provided further stabilization. The photoinduced formation of nanosized aggregates was detected by dynamic light scattering and atomic force microscopy. Absorption and emission spectroscopy were used to rule out photochemical reactions and elucidate the supramolecular arrangement. PMID:26088975

  6. 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

  7. 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.

  8. Prompt gamma activation analysis (PGAA) and short-lived neutron activation analysis (NAA) applied to the characterization of legacy materials

    SciTech Connect

    Firestone, Richard B; English, G.A.; Firestone, R.B.; Perry, D.L.; Reijonen, J.P.; Leung, Ka-Ngo; Garabedian, G.F.; Molnar, G.L.; Revay, Zs.

    2008-02-13

    Without quality historical records that provide the composition of legacy materials, the elemental and/or chemical characterization of such materials requires a manual analytical strategy that may expose the analyst to unknown toxicological hazards. In addition, much of the existing legacy inventory also incorporates radioactivity, and, although radiological composition may be determined by various nuclear-analytical methods, most importantly, gamma-spectroscopy, current methods of chemical characterization still require direct sample manipulation, thereby presenting special problems with broad implications for both the analyst and the environment. Alternately, prompt gamma activation analysis (PGAA) provides a'single-shot' in-situ, non-destructive method that provides a complete assay of all major entrained elemental constituents.1-3. Additionally, neutron activation analysis (NAA) using short-lived activation products complements PGAA and is especially useful when NAA activation surpasses the PGAA in elemental sensitivity.

  9. 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

  10. 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

  11. Determination of long-lived Nb isotopes in nuclear power plant wastes.

    PubMed

    Osváth, Szabolcs; Vajda, Nóra; Molnár, Zsuzsa

    2008-01-01

    (94)Nb and (93m)Nb are long-lived radionuclides, produced by thermal and fast neutrons from (93)Nb that is a major component of the Zr alloys used in nuclear reactors. A radiochemical method for the determination of these nuclides has been developed. The separation is based on the insolubility of Nb oxides and the retention of the fluoric complexes on anion exchange resin. The Nb sources are detected by gamma- and X-ray spectrometries. Activity concentrations determined in radioactive waste samples of a nuclear power plant are presented. PMID:17716901

  12. The Effect of Isotopic Substitution on Quantum Proton Transfer Across Short Water Bridges in Biological Systems

    NASA Astrophysics Data System (ADS)

    Blazejewski, Jacob; Schultz, Chase; Mazzuca, James

    2015-03-01

    Many biological systems utilize water chains to transfer charge over long distances by means of an excess proton. This study examines how quantum effects impact these reactions in a small model system. The model consists of a water molecule situated between an imidazole donor and acceptor group, which simulate a fixed amino acid backbone. A one dimensional energy profile is evaluated using density functional theory at the 6-31G*/B3LYP level, which generates a barrier with a width of 0.6 Å and a height of 20.7 kcal/mol. Quantum transmission probability is evaluated by solving the time dependent Schrödinger equation on a grid. Isotopic effects are examined by performing calculations with both hydrogen and deuterium. The ratio of hydrogen over the deuterium shows a 130-fold increase in transmission probability at low temperatures. This indicates a substantial quantum tunneling effect. The study of higher dimensional systems as well as increasing the number of water molecules in the chain will be necessary to fully describe the proton transfer process. Alma College Provost's Office.

  13. 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.

  14. 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.

  15. 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.

  16. Diet restriction and life history trade-offs in short- and long-lived species of Daphnia.

    PubMed

    Latta, Leigh Clark; Frederick, Shannon; Pfrender, Michael Eugene

    2011-12-01

    The life-extending effects of diet restriction are well documented. One evolutionary model that accounts for this widespread conservation is the resource allocation model, where the selected individuals are those that can delay reproduction during periods of resource limitation. In this study, we use closely related species of a model organism, Daphnia, with widely divergent lifespans to address the relationship between diet restriction and longevity and assess whether the relationships are owing to trade-offs between reproductive and somatic investment. Specifically, we conducted a common garden experiment and constructed reaction norms for lifespan, fecundity, and body size as a function of food concentration. Our study provides evidence that the short-lived species in our study, D. pulex, shows the classically observed relationship of enhanced lifespan in response to reduced diet intake, but does not divert resources to somatic maintenance at the expense of reproduction during chronic diet restriction. In contrast, we find no evidence that the long-lived species in our study, D. pulicaria, gains any life-extending effects through diet restriction. Combined, our results provide evidence that the resource allocation model is not sufficient to explain the evolution of diet-mediated lifespan plasticity. PMID:21953827

  17. Effects of dietary composition on life span of Drosophila buzzatii and its short-lived sibling species D. koepferae.

    PubMed

    Gomez, Federico H; Sambucetti, Pablo; Norry, Fabian M

    2013-08-01

    Two sibling Drosophila species dramatically divergent in longevity, Drosophila buzzatii and D. koepferae, were examined for possible effects of both developmental culture medium and dietary composition (DC) on longevity. Longevity was greatly increased in the longer lived D. buzzatii when flies were reared and fed on a rich-in-nutrient and cactus-based culture (R-CBC) as compared to longevity in a poor nutrient culture (PNC). In D. buzzatii, life span was further increased by exposing flies to short periods of a poor-in-nutrient and cactus-based culture (P-CBC). In contrast, variation in the here used nutrient composition did not change life span in the shorter lived D. koepferae, as longevity in this species did not differ among R-CBC, P-CBC and PNC cultures. Hormesis is a plausible explanation for the beneficial biological effects against aging arising from brief exposure to a lowed calorie food source in D. buzzatii. This study shows that genetic variation between closely related species is substantial for dietary effects on longevity. PMID:23835870

  18. Iodine-131: a potential short-lived, wastewater-specific particle tracer in an urbanized estuarine system.

    PubMed

    Smith, Joseph P; Oktay, Sarah I; Kada, John; Olsen, Curtis R

    2008-08-01

    The short-lived, fission-produced radioisotope, 131I (t1/2 = 8.04 days), was detected in wastewater, surficial sediment, and suspended particulate matter (SPM) samples collected from New York Harbor (NYH) between 2001 and 2002. lodine-131 is used as a radiopharmaceutical for medical imaging, diagnostics, and treatments for conditions of the thyroid. It is introduced into the municipal waste stream by medical facilities and patients and is subsequently released into the estuary via wastewater effluent. Measured 131I activities in surface sediments were correlated with those of 7Be (t1/2 = 53.2 days), a naturally occurring radioisotope that is widely used to quantify particle dynamics, sediment focusing, and short-term sediment deposition and accumulation in aquatic systems. Surficial sediment 131I activities were also compared with measured trace metal (Cu, Pb) and organic carbon (OC(sed)) concentrations which can be linked to wastewater inputs. These preliminary results from NYH introduce 131I as a potentially valuable source-specific, shortlived biogeochemical tracer (timescales < 1 month) for particles, sediments, and wastewater-sourced contaminants in urbanized aquatic systems. PMID:18754457

  19. 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:11541324

  20. Short-lived fission product measurements from >0.1 MeV neutron-induced fission using boron carbide.

    SciTech Connect

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

    2012-02-01

    A boron carbide shield was designed, custom fabricated, and used to create a fast fission energy neutron spectrum. The fissionable isotopes 233, 235, 238U, 237Np, and 239Pu were separately placed inside of this shield and irradiated under pulsed conditions at the Washington State University 1 MW TRIGA reactor. A unique set of fission product gamma spectra were collected at short times (4 minutes to 1 week) post-fission. Gamma spectra were collected on single-crystal high purity germanium detectors and on Pacific Northwest National Laboratory's (PNNL's) Direct Simultaneous Measurement (DSM) system composed of HPGe detectors connected in coincidence. This work defines the experimental methods used to produce and collect the gamma data, and demonstrates the validity of the measurements. It is important to fully document this information so the data can be used with high confidence for the advancement of nuclear science and non-proliferation applications. The gamma spectra collected in these and other experiments will be made publicly available at https://spcollab.pnl.gov/sites/gammadata or via the link at http://rdnsgroup.pnl.gov. A revised version of this publication will be posted with the data to make the experimental details available to those using the data.

  1. 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.

  2. 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.

  3. SHORT-TERM (INTESTINAL) AND LONG-TERM (WHOLE BODY) CONVERSION OF BETA-CAROTENE TO VITAMIN A IN ADULTS USING A STABLE ISOTOP REFERENCE METHOD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantitative and detailed information on the conversion of beta-carotene (b-C) to vitamin A in humans is limited. Our objective is to determine the short and long term conversion of synthetic deuterium labeled b-C to vitamin A in well-nourished adults by using a stable isotope reference method. A p...

  4. Effects of East Asian Short-lived Anthropogenic Air Pollutants on the Northern Hemispheric Air Quality and Climate

    NASA Astrophysics Data System (ADS)

    Liu, J.; Horowitz, L. W.; Lau, N.; Fan, S.; Tao, S.; Mauzerall, D. L.; Levy, H.

    2012-12-01

    Short-lived anthropogenic pollutants (such as ozone and aerosols) not only degrade ambient air quality and influence human health, but also play an important role in scattering/absorbing atmospheric radiation and disturbing regional climate. Due to the rapid industrialization, anthropogenic emissions from East Asia (EA) have increased substantially during the past decades. At the same time, EA has experienced a changing climate in terms of surface temperature and precipitation. In order to understand to what extent that EA short-lived anthropogenic emissions could influence domestic and downwind air quality (e.g. surface O3 and PM2.5), and explore the potential linkage between hemispheric-scale climate perturbation and regional anthropogenic forcing, we simulate global climate and chemical compositions during 1981-2000 based on the coupled general circulation model CM3 for atmosphere (with interactive tropospheric and stratospheric chemistry), oceans, land and sea ice, recently developed at Geophysical Fluid Dynamics Laboratory (GFDL/NOAA). We also conduct a parallel sensitivity simulation which is identical to the base simulation but with all anthropogenic emissions over EA turned off. The difference between the base and sensitivity simulations represents the short-term response of the Northern Hemispheric climate system and atmospheric composition to the perturbation of regional anthropogenic forcing. We find that East Asian short-lived anthropogenic emissions exert significant adverse impacts on local air quality during 1981-2000, accounting for 10-30ppbV daily-averaged O3 over Eastern China in JJA. In particular, EA anthropogenic emissions elevate the summertime daily maximum 8-hour average ozone (MDA8 O3) by 30-40ppbV over the North China Plain, where the typical background MDA8 ozone ranges 30 to 45ppbV. In addition, the surface PM2.5 concentrations peak at the same season and over the same region, with a seasonal mean of 10-30ug/m3, mostly contributed from local anthropogenic sources. In terms of long-range transport, anthropogenic pollutants from EA generally account for 2-5ppbv surface ozone from east to west mid-latitude North Pacific, but with distinct seasonal variability. During spring, EA anthropogenic emissions enhance nearly 2ppbV ozone over the west coast of California, USA, which increases the number of days when MADA8 exceeds 75ppbV by 2~5days/season in JJA. We find that the high aerosol loadings over EA significantly elevate aerosol optical depth (AOD) over Eastern China (0.2-0.4 in DJF and 0.3-0.5 in JJA), which warms up the atmosphere (15~20 Watts/m2) at the expense of cooling the surface (-30~-20 Watts/m2), potentially reducing the local surface temperature by -0.5K ~ -2K. Moreover, our model results also show that EA anthropogenic pollutants significantly depress local precipitation rate (up to 1.5 mm/day) and rain frequency (4-10 days/season), particularly over South and Southwestern China. This may partly explain the change of seasonal precipitation patterns over EA during the past decades.

  5. Production rates and metabolism of short-chain fatty acids in the colon and whole body using stable isotopes.

    PubMed

    Pouteau, Etienne; Nguyen, Patrick; Ballèvre, Olivier; Krempf, Michel

    2003-02-01

    Short-chain fatty acids (SCFA; mainly acetate, propionate and butyrate) are largely produced in non-ruminants during the colonic bacterial fermentation of non-digestible carbohydrates. These intestinal exogenous SCFA pass in part through the splanchnic bed and reach the peripheral bloodstream, mixing with the endogenous circulating SCFA. The whole-body turnover of SCFA is thus composed of an endogenous peripheral turnover and an exogenous production that depends on dietary intake of non-digestible carbohydrates. In the present work methods were developed for determining the SCFA turnover in animals and in human subjects using stable isotopes. The original studies performed to determine endogenous and exogenous metabolism of SCFA in animals and in human subjects are summarised. Using intravenous infusion of 13C-labelled SCFA the whole-body turnover of acetate, propionate and butyrate was assessed in rats in a fasted state. The endogenous turnover of acetate and its oxidation were determined in healthy human subjects in the post-absorptive state, using intravenous infusion of [1-13C]acetate. Intragastric tracer infusions were performed to evaluate the splanchnic first-pass retention of acetate in adults. Finally, an original model was developed in healthy human subjects using intravenous infusion of [1-13C]acetate to determine in vivo the true colonic acetate production after ingestion of a non-digestible disaccharide. These present studies using stable isotopes provide the basis for a novel strategy to evaluate in vivo, in human subjects, the production of SCFA in the large intestine. PMID:12740063

  6. PTF10iya: a short-lived, luminous flare from the nuclear region of a star-forming galaxy

    NASA Astrophysics Data System (ADS)

    Cenko, S. Bradley; Bloom, Joshua S.; Kulkarni, S. R.; Strubbe, Linda E.; Miller, Adam A.; Butler, Nathaniel R.; Quimby, Robert M.; Gal-Yam, Avishay; Ofek, Eran O.; Quataert, Eliot; Bildsten, Lars; Poznanski, Dovi; Perley, Daniel A.; Morgan, Adam N.; Filippenko, Alexei V.; Frail, Dale A.; Arcavi, Iair; Ben-Ami, Sagi; Cucchiara, Antonio; Fassnacht, Christopher D.; Green, Yoav; Hook, Isobel M.; Howell, D. Andrew; Lagattuta, David J.; Law, Nicholas M.; Kasliwal, Mansi M.; Nugent, Peter E.; Silverman, Jeffrey M.; Sullivan, Mark; Tendulkar, Shriharsh P.; Yaron, Ofer

    2012-03-01

    We present the discovery and characterization of PTF10iya, a short-lived (Δt≈ 10 d, with an optical decay rate of ˜0.3 mag d-1), luminous (? mag) transient source found by the Palomar Transient Factory. The ultraviolet/optical spectral energy distribution is reasonably well fitted by a blackbody with T≈ (1-2) × 104 K and peak bolometric luminosity LBB≈ (1-5) × 1044 erg s-1 (depending on the details of the extinction correction). A comparable amount of energy is radiated in the X-ray band that appears to result from a distinct physical process. The location of PTF10iya is consistent with the nucleus of a star-forming galaxy (z= 0.224 05 ± 0.000 06) to within 350 mas (99.7 per cent confidence radius), or a projected distance of less than 1.2 kpc. At first glance, these properties appear reminiscent of the characteristic 'big blue bump' seen in the near-ultraviolet spectra of many active galactic nuclei (AGNs). However, emission-line diagnostics of the host galaxy, along with a historical light curve extending back to 2007, show no evidence for AGN-like activity. We therefore consider whether the tidal disruption of a star by an otherwise quiescent supermassive black hole may account for our observations. Though with limited temporal information, PTF10iya appears broadly consistent with the predictions for the early 'super-Eddington' phase of a solar-type star being disrupted by a ˜107 M⊙ black hole. Regardless of the precise physical origin of the accreting material, the large luminosity and short duration suggest that otherwise quiescent galaxies can transition extremely rapidly to radiate near the Eddington limit; many such outbursts may have been missed by previous surveys lacking sufficient cadence.

  7. Short-lived tectonic switch mechanism for long-term pulses of volcanic activity after mega-thrust earthquakes

    NASA Astrophysics Data System (ADS)

    Lupi, M.; Miller, S. A.

    2014-01-01

    Eruptive rates in volcanic arcs increase significantly after subduction mega-thrust earthquakes. Over short to intermediate time periods the link between mega-thrust earthquakes and arc response can be attributed to dynamic triggering processes or static stress changes, but a fundamental mechanism that controls long-term pulses of volcanic activity after mega-thrust earthquakes has not been proposed yet. Using geomechanical, geological, and geophysical arguments, we propose that increased eruption rates over longer timescales are due to the relaxation of the compressional regime that accompanies mega-thrust subduction zone earthquakes. More specifically, the reduction of the horizontal stress σh promotes the occurrence of short-lived strike-slip kinematics rather than reverse faulting in the volcanic arc. The relaxation of the pre-earthquake compressional regime facilitates magma mobilisation by providing a short-circuit pathway to shallow depths by significantly increasing the hydraulic properties of the system. The timescale for the onset of strike-slip faulting depends on the degree of shear stress accumulated in the arc during inter-seismic periods, which in turn is connected to the degree of strain-partitioning at convergent margins. We performed Coulomb stress transfer analysis to determine the order of magnitude of the stress perturbations in present-day volcanic arcs in response to five recent mega-thrust earthquakes; the 2005 M8.6, 2007 M8.5, and 2007 M7.9 Sumatra earthquakes; the 2010 M8.8 Maule, Chile earthquake; and the 2011 M9.0 Tohoku, Japan earthquake. We find that all but one the shallow earthquakes that occurred in the arcs of Sumatra, Chile and Japan show a marked lateral component. We suggests that the long-term response of volcanic arcs to subduction zone mega-thrust earthquakes will be manifested as predominantly strike-slip seismic events, and that these future earthquakes may be followed closely by indications of rising magma to shallower depths, e.g. surface inflation and seismic swarms.

  8. Short-lived tectonic switch mechanism for long-term pulses of volcanic activity after mega-thrust earthquakes

    NASA Astrophysics Data System (ADS)

    Lupi, M.; Miller, S. A.

    2013-06-01

    Eruptive rates in volcanic arcs increase significantly after mega-thrust earthquakes in subduction zones. Over short to intermediate time periods the link between mega-thrust earthquakes and arc response can be attributed to dynamic triggering processes or static stress changes, but a fundamental mechanism that controls long-term pulses of volcanic activity after mega-thrust earthquakes has not been proposed yet. Using geomechanical, geological, and geophysical arguments, we propose that increased eruption rates over longer timescales are due to the relaxation of the compressional regime that accompanies mega-thrust subduction zone earthquakes. More specifically, the reduction of the horizontal stress σh promotes the occurrence of short-lived strike-slip kinematics rather than reverse faulting in the volcanic arc. The relaxation of the pre-earthquake compressional regime facilitates magma mobilization by providing a short-circuit pathway to shallow depths by significantly increasing the hydraulic properties of the system. The timescale for the onset of strike-slip faulting depends on the degree of shear stress accumulated in the arc during inter-seismic periods, which in turn is connected to the degree of strain-partitioning at convergent margins. We performed Coulomb stress transfer analysis to determine the order of magnitude of the stress perturbations in present-day volcanic arcs in response to five actual mega-thrust earthquakes; the 2005 M8.6, 2007 M8.5, and 2007 M7.9 Sumatra earthquakes; the 2010 M8.8 Maule, Chile earthquake; and the 2011 M9.0 Tohoku, Japan earthquake. We find that all, but one, the shallow earthquakes that occurred in the arcs of Sumatra, Chile and Japan show a marked lateral component. Our hypothesis suggests that the long-term response of volcanic arcs to subduction zone mega-thrust earthquakes will be manifested as predominantly strike-slip seismic events, and that these future earthquakes will be followed closely by seismic swarms, inflation, and other indications of a rising magma source.

  9. 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

  10. Occurrence of adventitious sprouting in short-lived monocarpic herbs: a field study of 22 weedy species

    PubMed Central

    Malíková, Lenka; Šmilauer, Petr; Klimešová, Jitka

    2010-01-01

    Background and Aims Adventitious sprouting from the hypocotyle and roots in monocarpic herbs has been confirmed in previous experimental studies as a means to avoid bud limitation after severe injury in annual and biennial plants. Data regarding the role of adventitious sprouting in natural populations, however, were lacking. The aim of the present study was to assess whether adventitious sprouting occurs in natural populations and how it is affected by plant size, plant injury, plant cover and environmental characteristics. Methods Data were sampled from 14 037 individual plants from 389 populations belonging to 22 annual and biennial species. Growth parameters were measured in individual plants, species composition and plant cover in communities were evaluated, and environmental characteristics were estimated using Ellenberg indicator values. Key Results It was confirmed that adventitious sprouting occurs in natural populations of all but five species examined. Adventitious sprouting was positively affected by plant size and plant injury. Environmental factors including availability of soil nitrogen were not shown to affect adventitious sprouting. Annual and biennial plants did not differ in sprouting, but upright annuals had a lower number of and longer adventitious shoots than prostrate annuals. Conclusions Adventitious bud formation is used to overcome meristem limitation when stem parts are lost due to injury, and thus resprouting in short-lived monocarps should not be overlooked. PMID:20356953

  11. Short-lived 244Pu points to compact binary mergers as sites for heavy r-process nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Hotokezaka, Kenta; Piran, Tsvi; Paul, Michael

    2015-12-01

    The origin of heavy elements produced through rapid neutron capture (`r-process’) by seed nuclei is one of the current nucleosynthesis mysteries. Core collapse supernovae (cc-SNe; ref. ) and compact binary mergers are considered as possible sites. The first produces small amounts of material at a high event rate whereas the latter produces large amounts in rare events. Radioactive elements with the right lifetime can break the degeneracy between high-rate/low-yield and low-rate/high-yield scenarios. Among radioactive elements, most interesting is 244Pu (half-life of 81 million years), for which both the current accumulation of live 244Pu particles accreted via interstellar particles in the Earth’s deep-sea floor and the Early Solar System (ESS) abundances have been measured. Interestingly, the estimated 244Pu abundance in the current interstellar medium inferred from deep-sea measurements is significantly lower than that corresponding to the ESS measurements. Here we show that both the current and ESS abundances of 244Pu are naturally explained within the low-rate/high-yield scenario. The inferred event rate remarkably agrees with compact binary merger rates estimated from Galactic neutron star binaries and from short gamma-ray bursts. Furthermore, the ejected mass of r-process elements per event agrees with both theoretical and observational macronova/kilonova estimates.

  12. Impact of Very Short-lived Halogens on Stratospheric Ozone Abundance and UV radiation in a Geo-engineered Atmosphere

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Kinnison, D. E.; Garcia, R. R.; Salawitch, R. J.; Canty, T. P.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-12-01

    The impact of BrO from very short-lived (VSL) source species on stratospheric ozone is investigated for a hypothetical geo-engineered atmosphere in 2040, assuming the injection of sulfuric acid aerosols. An estimated amount of stratospheric halogens from VSL sources based on satellite observations, model results and previous studies, result in lower column ozone for nearly all seasons and nearly all latitudes, and up to 4% in summer mid- and high latitudes. Considering an upper limit of VSL sources, the annual increase in surface erythemal UV radiation (UV_ERY) due to the decrease in ozone as a result of geo-engineering is 12% and 6% in southern and northern high latitudes, respectively. The increase of UV_ERY due to a reduction of ozone for low and mid latitudes is balanced by the reduction of UV_ERY due to aerosol scattering, if VSL halogen sources are not considered. However, VSL halogens results in additional ozone depletion and in an increase of UV_ERY of up to 5% in spring and fall in mid- and high latitudes as a result of geo-engineering. This study demonstrates that VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

  13. Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Kinnison, D. E.; Garcia, R. R.; Salawitch, R.; Canty, T.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-11-01

    The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UVERY) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UVERY due to geo-engineering for nearly all seasons and latitudes, with UVERY rising by 12% and 6% in southern and northern high latitudes, respectively. When VSL halogen sources are neglected, future UVERY increases due to declines in ozone column are nearly balanced by reductions of UVERY due to scattering by the higher stratospheric aerosol burden in mid-latitudes. Consideration of VSL sources at their upper limit tips the balance, resulting in annual average increases in UVERY of up to 5% in mid and high latitudes. Therefore, VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

  14. Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Kinnison, D. E.; Garcia, R. R.; Salawitch, R.; Canty, T.; Lee-Taylor, J.; Madronich, S.; Chance, K.

    2012-08-01

    The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UVERY) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UVERY due to geo-engineering for nearly all seasons and latitudes, with UVERY rising by 12% and 6% in southern and northern high latitudes, respectively. When VSL halogen sources are neglected, future UVERY increases due to declines in ozone column are nearly balanced by reductions of UVERY due to scattering by the higher stratospheric aerosol burden in mid-latitudes. Consideration of VSL sources at their upper limit tips the balance, resulting in annual average increases in UVERY of up to 5% in mid and high latitudes. Therefore, VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.

  15. 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

  16. 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.

  17. Plasmacytoid dendritic cells are short-lived: reappraising the influence of migration, genetic factors and activation on estimation of lifespan.

    PubMed

    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

  18. 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.

  19. Mesenchymal stem cells are short-lived and do not migrate beyond the lungs after intravenous infusion

    PubMed Central

    Eggenhofer, E.; Benseler, V.; Kroemer, A.; Popp, F. C.; Geissler, E. K.; Schlitt, H. J.; Baan, C. C.; Dahlke, M. H.; Hoogduijn, M. J.

    2012-01-01

    Mesenchymal stem cells (MSC) are under investigation as a therapy for a variety of disorders. Although animal models show long term regenerative and immunomodulatory effects of MSC, the fate of MSC after infusion remains to be elucidated. In the present study the localization and viability of MSC was examined by isolation and re-culture of intravenously infused MSC. C57BL/6 MSC (500,000) constitutively expressing DsRed-fluorescent protein and radioactively labeled with Cr-51 were infused via the tail vein in wild-type C57BL/6 mice. After 5 min, 1, 24, or 72 h, mice were sacrificed and blood, lungs, liver, spleen, kidneys, and bone marrow removed. One hour after MSC infusion the majority of Cr-51 was found in the lungs, whereas after 24 h Cr-51 was mainly found in the liver. Tissue cultures demonstrated that viable donor MSC were present in the lungs up to 24 h after infusion, after which they disappeared. No viable MSC were found in the other organs examined at any time. The induction of ischemia-reperfusion injury in the liver did not trigger the migration of viable MSC to the liver. These results demonstrate that MSC are short-lived after i.v. infusion and that viable MSC do not pass the lungs. Cell debris may be transported to the liver. Long term immunomodulatory and regenerative effects of infused MSC must therefore be mediated via other cell types. PMID:23056000

  20. Developmentally regulated instability of the GPI-PLC mRNA is dependent on a short-lived protein factor

    PubMed Central

    Webb, Helena; Burns, Roisin; Ellis, Louise; Kimblin, Nicola; Carrington, Mark

    2005-01-01

    The expression of the vast majority of protein coding genes in trypanosomes is regulated exclusively at the post-transcriptional level. Developmentally regulated mRNAs that vary in levels of expression have provided an insight into one mechanism of regulation; a decrease in abundance is due to a shortened mRNA half-life. The decrease in half-life involves cis-acting elements in the 3′ untranslated region of the mRNA. The trans-acting factors necessary for the increased rate of degradation remain uncharacterized. The GPI-PLC gene in Trypanosoma brucei encodes a phospholipase C expressed in mammalian bloodstream form, but not in the insect procyclic form. Here, it is reported that the differential expression of the GPI-PLC mRNA also results from a 10-fold difference in half-life. Second, the instability of the GPI-PLC mRNA in procyclic forms can be reversed by the inhibition of protein synthesis. Third, specifically blocking the translation of the GPI-PLC mRNA in procyclic forms by the inclusion of a hairpin in the 5′ untranslated region does not result in stabilization of the mRNA. Thus, the effect of protein synthesis inhibitors in stabilizing the GPI-PLC mRNA operates in trans through a short-lived factor dependent on protein synthesis. PMID:15755751

  1. Analysis of very short-lived halocarbons in the ocean and atmosphere using fully automated sampling techniques

    NASA Astrophysics Data System (ADS)

    Andrews, S. J.; Carpenter, L. J.

    2012-04-01

    Reactive halogen species, originating in part from very short-lived halocarbons (VSLH), play an important role in tropospheric chemistry. However, VSLH datasets are sparse compared to those of other important trace gases. In addition, calibration is non-trivial and a lack of a common scale limits their usefulness. A new, fully automated seawater analysis instrument was developed to provide near-continuous surface seawater measurements and semi-automated CTD measurements of VSLH. This instrument was deployed, alongside a new system for continuous on-line air measurements, during the Tropical Ocean tRoposphere Experiment of Reactive halogen species and OVOCs (TORERO) cruise. High frequency online air measurements, automated seawater measurements and simultaneous chlorophyll-α fluorescence will be reported for the duration of the cruise. The data will compliment VSLH measurements taken from onboard the NCAR G-V HIAPER aircraft to provide a comprehensive vertical profile from deep ocean to upper troposphere. Inter-comparison of standard gases used during the campaign will add confidence to results and link this data set with recent inter-comparisons in the UK and US.

  2. 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.

  3. The Effect of Cosmic Ray Irradiation on Platinum Isotopes in Iron Meteorites

    NASA Astrophysics Data System (ADS)

    Hunt, A. C.; Ek, M.; Schönbächler, M.

    2014-09-01

    The platinum isotope system is a useful dosimeter and a powerful tool for correcting the effects of galactic cosmic ray irradiation in short-lived chronometers. We present data for iron meteorites collected using a new chemical separation method.

  4. Stable Oxygen and Carbon Isotope Characteristics of Live Benthic Foraminifera from the Okhotsk Sea: Effects of Oceanography, Food Supply, and Microhabitat Patterns

    NASA Astrophysics Data System (ADS)

    Lembke-Jene, L.; Tiedemann, R.; Bubenshchikova, N.; Erlenkeuser, H.; Dullo, W.

    2008-12-01

    Paleoceanographic studies use benthic foraminiferal stable isotopes as proxies for interpretations of numerous parameters such as past oceanic circulation patterns, food supply, primary productivity, etc. However, only few studies have used live (rose Bengal-stained) populations to reliably calibrate stable isotope characteristics to bottom water and sediment chemistry of the surrounding environment. We report results from a study in the Okhotsk Sea, a region characterized by extreme climatic and oceanographic settings. Not only does this marginal basin of the NW-Pacific experience the southermost extent of seasonal ice cover in the entire Northern Hemisphere, it also shows extremely high primary productivity. These boundary conditions lead many to consider the Okhotsk Sea both as a modern analog for ecological and oceanographic conditions in ocean basins during past and a sensitive recorder of potential future climate change in high latitudes. We compare results of stable oxygen and carbon isotopes from the most abundant taxa to oxygen isotopic compositions of bottom water and carbon isotopes of bottom water DIC, nutrient inventories from the water column and productivity proxy-data from sediment surface profiles (chlorines, TOC, biogenic opal). Multicorer samples from the upper 10 cm at 15 sites were taken from a variety of settings with water depths ranging from less than 100 m to more than 3200 m. Results obtained show a wide range of interspecific carbon isotope values exceeding 2 per mil variability within neighbouring samples. Minimum values occur in deep endobenthic groups like Globobulima spp., whereas species living in a relatively wide depth range like V. sadonica or U. peregrina exhibit intermediate values between -0.7 and -1 per mil. Most measurements conducted to address intraspecific variability remain within a narrow range of less than 0.4 per mil. However, we do observe vertical trends with both increasing and decreasing carbon isotope gradients within the sediment column. Obtained carbon isotope values from both living and dead specimen of widely used the Cibicides spp. group stay within the range of bottom water DIC, with no systematic negative phytodetritus- effect occuring throughout the sample set despite etremely pronounced seasonality in organic matter supply on most sites. Combined with a proxy-dataset about primary productivity, we give an evaluation of benthic-pelagic coupling and the impact on benthic species adaption to the pronounced subarctic seasonal cycle and the strongly pulsed food fluxes to the ocean floor.

  5. Stable Oxygen and Carbon Isotope Characteristics of Live Benthic Foraminifera from the Okhotsk Sea: Effects of Oceanography, Food Supply and Microhabitat Patterns

    NASA Astrophysics Data System (ADS)

    Lembke-Jene, L.; Tiedemann, R.; Bubenshchikova, N.; Erlenkeuser, H.

    2009-04-01

    Paleoceanographic studies use benthic foraminiferal stable isotopes as proxies for interpretations of numerous parameters such as past oceanic circulation patterns, food supply, primary productivity, etc. However, only few studies have used live (rose Bengal-stained) populations to reliably calibrate stable isotope characteristics to bottom water and sediment chemistry of the surrounding environment. We report data from a study in the Okhotsk Sea, a region characterized by extreme climatic and oceanographic settings. Not only does this marginal basin of the NW-Pacific experience the southermost extent of seasonal ice cover in the entire Northern Hemisphere, it also shows extremely high primary productivity. These boundary conditions lead many to consider the Okhotsk Sea both as a modern analog for ecological and oceanographic conditions in ocean basins during past and a sensitive recorder of potential future climate change in high latitudes. We compare results of stable oxygen and carbon isotopes from the most abundant taxa to oxygen isotopic compositions of bottom water and carbon isotopes of bottom water DIC, nutrient inventories from the water column and productivity proxy-data from sediment surface profiles (chlorines, TOC, biogenic opal). Multicorer samples from the upper 10 cm at 15 sites were taken from a variety of settings with water depths ranging from less than 100 m to more than 3200 m. Results obtained show a wide range of interspecific carbon isotope values exceeding 2 per mil variability within neighbouring samples. Minimum values occur in deep endobenthic groups like Globobulima spp., whereas species living in a relatively wide depth range like V. sadonica or U. peregrina exhibit intermediate values between -0.7 and -1 per mil. Most measurements conducted to address intraspecific variability remain within a narrow range of less than 0.4 per mil. However, we do observe vertical trends with both increasing and decreasing carbon isotope gradients within the sediment column. Obtained carbon isotope values from both living and dead specimen of widely used the Cibicides spp. group stay within the range of bottom water DIC, with no systematic negative phytodetritus-effect occuring throughout the sample set despite etremely pronounced seasonality in organic matter supply on most sites. Combined with a proxy-dataset about primary productivity, we give an evaluation of benthic-pelagic coupling and the impact on benthic species adaption to the pronounced subarctic seasonal cycle and the strongly pulsed food fluxes to the ocean floor.

  6. 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.

  7. 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

  8. 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 folate equivalents has to be questioned and requires further investigation. PMID:25407846

  9. Starbursts and high-redshift galaxies are radioactive: high abundances of 26Al and other short-lived radionuclides

    NASA Astrophysics Data System (ADS)

    Lacki, Brian C.

    2014-06-01

    Short-lived radionuclides (SLRs) like 26Al are synthesized by massive stars and are a byproduct of star formation. The abundances of SLRs in the gas of a star-forming galaxy are inversely proportional to the gas consumption time. The rapid evolution of specific star formation rate (SSFR) of normal galaxies implies they had mean SLR abundances 3-10 times higher at z = 2. During the epoch of Solar system formation, the background SLR abundances of the Galaxy were up to twice as high as at present, if SLR yields from massive stars do not depend on metallicity. If SLRs are homogenized in the gas of galaxies, the high SSFRs of normal galaxies can partly explain the elevated abundance of SLRs like 60Fe and 26Al in the early Solar system. Starburst galaxies have much higher SSFRs still, and have enormous mean abundances of 26Al (26Al/27Al ?10-3 for solar metallicity gas). The main uncertainty is whether the SLRs are mixed with the star-forming molecular gas: they could be trapped in hot gas and decay before entering the colder phases, or be blown out by starburst winds. I consider how variability in star formation rate affects the SLR abundances, and I discuss how SLR transport may differ in these galaxies. The enhanced 26Al of starbursts might maintain moderate ionization rates (10-18-10-17 s-1), possibly dominating ionization in dense clouds not penetrated by cosmic rays. Similar ionization rates would be maintained in protoplanetary discs of starbursts, if the SLRs are well mixed, and the radiogenic heating of planetesimals would likewise be much higher. In this way, galaxy evolution can affect the geological history of planetary systems.

  10. ICV-Transplanted Human Glial Precursor Cells Are Short-Lived Yet Exert Immunomodulatory Effects in Mice with EAE

    PubMed Central

    KIM, HEECHUL; WALCZAK, PIOTR; MUJA, NASER; CAMPANELLI, JAMES T.; BULTE, JEFF W. M.

    2013-01-01

    Human glial precursor cells (hGPs) have potential for remyelinating lesions and are an attractive cell source for cell therapy of multiple sclerosis (MS). To investigate whether transplanted hGPs can affect the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of MS, we evaluated the therapeutic effects of transplanted hGPs together with the in vivo fate of these cells using magnetic resonance imaging (MRI) and bioluminescence imaging (BLI). At 14 days post-EAE induction, mice (n = 19) were intracerebroventricularly (ICV) injected with 5 × 105 hGPs that were magnetically labeled with superparamagnetic iron oxide (SPIO) particles as MR contrast agent and transduced with firefly luciferase for BLI of cell survival. Control mice (n = 18) received phosphate buffered saline (PBS) vehicle only. The severity of EAE clinical disability in the hGP-transplanted group was significantly suppressed (P < 0.05) with concomitant inhibition of ConA and MOG-specific T cell proliferation in the spleen. Astrogliosis was reduced and a lower activity of macrophages and/or microglia was observed in the spinal cord (P < 0.05). On MRI, SPIO signal was detected within the lateral ventricle from 1 day post-transplantation and remained there for up to 34 days. BLI indicated that most cells did not survive beyond 5–10 days, consistent with the lack of detectable migration into the brain parenchyma and the histological presence of an abundance of apoptotic cells. Transplanted hGPs could not be detected in the spleen. We conclude that ICV transplantation of short-lived hGPs can have a remote therapeutic effect through immunomodulation from within the ventricle, without cells directly participating in remyelination. PMID:22499166

  11. 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 levels.

  12. 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.

  13. 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.

  14. The effects of α-cellulose extraction and blue-stain fungus on retrospective studies of carbon and oxygen isotope variation in live and dead trees.

    PubMed

    English, Nathan B; McDowell, Nate G; Allen, Craig D; Mora, Claudia

    2011-10-30

    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 δ(13)C and δ(18)O 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 δ(13)C or δ(18)O 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 δ(13)C (up to 0.4‰) and δ(18) O (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 δ(13)C and δ(18)O of whole wood or α-cellulose. The relationships between whole wood and α-cellulose δ(13)C for ponderosa, piñon and juniper yielded slopes of ~1, while the relationship between δ(18)O 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. PMID:21953963

  15. 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.

  16. 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.

  17. 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 emission rates showed almost the same general trend, however, the total iodocarbon emission rates were about one to two orders of magnitude lower than those of molecular iodine, demonstrating that I(2) is the major iodine containing volatile released by the investigated seaweed species. In addition, a clear dependency of iodocarbon emission from the ozone level (0-150 ppb O(3)) was found for L. digitata. PMID:22227744

  18. 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 tropopause. This paper illustrates the mechanism by using results from a two-dimensional chemistry-transport model. However, in view of the importance of tropospheric transport on stratospheric loading the detailed values should be further evaluated using a three-dimensional model with appropriate treatment of convective transport.

  19. Analysis of Very Short-Lived Halocarbons in the Eastern Tropical Pacific Ocean and Atmosphere using Fully Automated Sampling Techniques

    NASA Astrophysics Data System (ADS)

    Andrews, S. J.; Lidster, R.; Carpenter, L.

    2012-12-01

    Reactive halogen species, originating in part from very short-lived halocarbons (VSLH), play an important role in tropospheric chemistry, in particular their reaction with ozone to form halogen oxides. Oceanic iodocarbon production is believed to be a significant source of IO. Unfortunately, VSLH datasets are sparse compared to those of other important trace gases, especially in oligotrophic oceans and the equatorial Pacific where recent satellite retrievals from SCIAMACHY show elevated levels of iodine oxide in the free troposphere. A new, fully automated purge and trap- thermal desorption system coupled to a GC-MS was developed to provide continuous measurement of VSLH in water sampled from a ship's surface seawater inlet and semi-automated analysis of bottle samples from CTD (Conductivity, Temperature Depth) casts. This instrument was deployed on NOAA vessel Ka'imimoana, alongside a new system for continuous on-line air measurements (TD-GC-MS), during the Tropical Ocean tRoposphere Experiment of Reactive halogen species and OVOCs (TORERO) campaign. High frequency boundary layer and surface seawater measurements are presented here with ocean depth profiling of VSLH along the 110°W TOA buoy line. Owing to the high sample throughput and continuous sampling, photolysis driven processes of iodocarbons in the ocean have been observed which have previously only been predicted in modelling and laboratory studies. Sea-air fluxes have been calculated along the cruise track using corresponding meteorological data from the ship. Extensive, open-ocean VSLH flux data is presented which, for the region of this study, is missing or sparse in the WMO ozone assessment of 2010. Inter-comparison of a standard gas used during the campaign allows the use of a single calibration scale (NOAA GMD) between research groups which adds confidence to the results and allows collation of data from the ship with simultaneous measurements taken on-board the NSF/NCAR G-V aircraft using the NCAR Trace Organic Gas Analyzer (TOGA). The inter-comparison will additionally link these data sets with recent inter-comparisons in the UK and US.

  20. {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.

  1. [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. PMID:23755551

  2. 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

  3. Comment on 'Electron-induced bond breaking at low energies in HCOOH and glycine: The role of very short-lived {sigma}* anion states'

    SciTech Connect

    Rescigno, T. N.; Trevisan, C. S.; Orel, A. E.

    2009-10-15

    Recent model calculations by Gallup et al. [Phys. Rev. A79, 042710 (2009)] suggest that low-energy dissociative electron attachment to formic acid can be explained solely in terms of a very short-lived {sigma}* anion state and that no {sigma}*/{pi}* coupling is required. We argue that this interpretation of the experimental data, which is at odds with our earlier study, is flawed.

  4. 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. PMID:27130103

  5. ?-decay half-lives including first-forbidden contributions for neutron-rich Zn isotopes in the extended QRPA with neutron-proton pairing

    NASA Astrophysics Data System (ADS)

    Ni, Dongdong; Ren, Zhongzhou

    2014-12-01

    The ? decays of neutron-rich Zn isotopes are investigated within the extended quasiparticle random-phase approximation, where neutron-neutron, proton-proton, and neutron-proton pairing correlations are considered in the similar manner. The Brckner G-matrix obtained with the charge-dependent Bonn nucleon-nucleon force is used for the residual particle-particle and particle-hole interactions in addition to the pairing interactions. Contributions from both allowed Gamow-Teller and first-forbidden transitions are considered, and ?-decay half-lives together with ?-delayed neutron emission probabilities are calculated. The calculated results are found to agree well with the available experimental data.

  6. 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 mol/L) and quantification limits (14-22 mol/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 formic acid prevented the adsorption of SCFA in the column, thereby eliminating peak tailing and ghost peaks. The applicability of the validated GC/MS method for determining the concentration of acetate and its (13)C isotope enrichment in anaerobic digester samples was tested and the results demonstrated the suitability of this method for identifying the metabolic pathways involved in degradation and production of acetate. PMID:26078128

  7. 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. PMID:12384694

  8. Species Selection Favors Dispersive Life Histories in Sea Slugs, but Higher Per-Offspring Investment Drives Shifts to Short-Lived Larvae.

    PubMed

    Krug, Patrick J; Vendetti, Jann E; Ellingson, Ryan A; Trowbridge, Cynthia D; Hirano, Yayoi M; Trathen, Danielle Y; Rodriguez, Albert K; Swennen, Cornelis; Wilson, Nerida G; Valdés, Ángel A

    2015-11-01

    For 40 years, paleontological studies of marine gastropods have suggested that species selection favors lineages with short-lived (lecithotrophic) larvae, which are less dispersive than long-lived (planktotrophic) larvae. Although lecithotrophs appeared to speciate more often and accumulate over time in some groups, lecithotrophy also increased extinction rates, and tests for state-dependent diversification were never performed. Molecular phylogenies of diverse groups instead suggested lecithotrophs accumulate without diversifying due to frequent, unidirectional character change. Although lecithotrophy has repeatedly originated in most phyla, no adult trait has been correlated with shifts in larval type. Thus, both the evolutionary origins of lecithotrophy and its consequences for patterns of species richness remain poorly understood. Here, we test hypothesized links between development mode and evolutionary rates using likelihood-based methods and a phylogeny of 202 species of gastropod molluscs in Sacoglossa, a clade of herbivorous sea slugs. Evolutionary quantitative genetics modeling and stochastic character mapping supported 27 origins of lecithotrophy. Tests for correlated evolution revealed lecithotrophy evolved more often in lineages investing in extra-embryonic yolk, the first adult trait associated with shifts in development mode across a group. However, contrary to predictions from paleontological studies, species selection actually favored planktotrophy; most extant lecithotrophs originated through recent character change, and did not subsequently diversify. Increased offspring provisioning in planktotrophs thus favored shifts to short-lived larvae, which led to short-lived lineages over macroevolutionary time scales. These findings challenge long-standing assumptions about the effects of alternative life histories in the sea. Species selection can explain the long-term persistence of planktotrophy, the ancestral state in most clades, despite frequent transitions to lecithotrophy. PMID:26163664

  9. 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.

  10. 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.

  11. Freshly induced short-lived gamma-ray activity as a measure of fission rates in lightly re-irradiated spent fuel

    NASA Astrophysics Data System (ADS)

    Kröhnert, H.; Perret, G.; Murphy, M. F.; Chawla, R.

    2010-12-01

    A new measurement technique has been developed to determine fission rates in burnt fuel, following re-irradiation in a zero-power research reactor. The development has been made in the frame of the LIFE@PROTEUS program at the Paul Scherrer Institute, which aims at characterizing the interfaces between fresh and highly burnt fuel assemblies in modern LWRs. To discriminate against the high intrinsic gamma-ray activity of the burnt fuel, the proposed measurement technique uses high-energy gamma-rays, above 2000 keV, emitted by short-lived fission products freshly produced in the fuel. To demonstrate the feasibility of this technique, a fresh UO 2 sample and a 36 GWd/t burnt UO 2 sample were irradiated in the PROTEUS reactor and their gamma-ray activities were recorded directly after irradiation. For both fresh and the burnt fuel samples, relative fission rates were derived for different core positions, based on the short-lived 142La (2542 keV), 89Rb (2570 keV), 138Cs (2640 keV) and 95Y (3576 keV) gamma-ray lines. Uncertainties on the inter-position fission rate ratios were mainly due to the uncertainties on the net-area of the gamma-ray peaks and were about 1-3% for the fresh sample, and 3-6% for the burnt one. Thus, for the first time, it has been shown that the short-lived gamma-ray activity, induced in burnt fuel by irradiation in a zero-power reactor, can be used as a quantitative measure of the fission rate. For both fresh and burnt fuel, the measured results agreed, within the uncertainties, with Monte Carlo (MCNPX) predictions.

  12. Short-lived vegetational and environmental change during the Preboreal in the Biebrza Upper Basin (NE Poland)

    NASA Astrophysics Data System (ADS)

    de Klerk, Pim; Couwenberg, John; Joosten, Hans

    2007-08-01

    A pollen diagram from the upper Biebrza basin (NE Poland) shows a conspicuous pollen fluctuation around 9650 BP, which is superimposed on a broader pollen fluctuation correlated with a more open vegetation phase during the Preboreal generally found in Europe. High-resolution pollen analyses indicate a duration of only a few years in which Pinus forests became more open. The resulting niches were partly occupied by Betula trees and partly by Betula shrubs, Artemisia, and Chenopodiaceae. Shortly before the increased opening of the upland vegetation, reed vegetation developed in the valley, in which Sparganium and later Typha became prominent. At the end of the short fluctuation, this reed vegetation diminished. The wetland vegetation development might be partly related to hydrological changes caused by a reduced evapotranspiration of the opened upland forest. The data presented here show that the open vegetation phase of the Preboreal was not of uniform character, but that within its short time span of ca 150 years an even shorter fluctuation of a few years to a few decades occurred. It is unknown whether this is a regionally restricted phenomenon or whether it has an extra-regional character.

  13. An alternative approach to comparing long- and short-lived emissions in light of the 2&amp;deg;C global temperature limit

    NASA Astrophysics Data System (ADS)

    Smith, Stephen; Bowerman, Niel; Lowe, Jason; Huntingford, Chris; Frame, Dave; Allen, Myles; Gohar, Laila; Millar, Richard

    2014-05-01

    International climate policy has defined its goal in terms of limiting global average temperature, specifically to 2°C above pre-industrial levels. Emissions of several different greenhouse gases (GHGs) are currently aggregated and traded in terms of their carbon dioxide equivalent. The metric used for aggregating and trading is the 100-year Global Warming Potential (GWP100). Importantly though, the GWP100 does not measure temperature and so does clearly indicate the relative value of different emissions in the context of a global temperature limit. Recent developments in climate research have led to two different, potentially conflicting, perspectives on priorities in reducing emissions. First, a clear link has been demonstrated between cumulative emissions of carbon dioxide and peak temperature. This emphasises the need for carbon dioxide emissions to fall to near zero and provides a conceptually neat way to frame policy, but says little about the role of other GHGs. Second, other studies have shown that emissions of short-lived climate pollutants (SLCPs), many of which currently lie outside climate policy, have a substantial near-term effect on climate. It has been suggested that immediate SLCP reductions will therefore increase the chance of staying below 2°C and may even "buy time" for carbon dioxide reductions. This presentation summarises two recent papers which clarify the roles of SLCPs and long-lived GHGs in determining peak global temperature, and propose new emission metrics to reflect these. SLCP emissions reductions in a given decade have a significant impact on peak temperature only if carbon dioxide emissions are already falling. Immediate action on SLCPs might potentially "buy time" for adaptation by reducing near-term warming, but it does not buy time to delay reductions in carbon dioxide compared with delayed SLCP reductions. Peak temperature is ultimately constrained by cumulative emissions of several long-lived gases (including carbon dioxide) and sustained emission rates of a separate basket of shorter-lived species (including methane and other SLCPs). For these two baskets we develop an emissions-equivalence metric which allows trading within, but not between, each basket. The 2°C limit could therefore be met by setting a limit to cumulative long-lived emissions while setting a maximum future rate for short-lived emissions.

  14. Short-lasting systemic and regional benefits of early crystalloid infusion after intravenous inoculation of dogs with live Escherichia coli.

    PubMed

    Garrido, A G; Poli de Figueiredo, L F; Cruz, R J; Silva, E; Rocha E Silva, M

    2005-06-01

    We investigated the systemic and regional hemodynamic effects of early crystalloid infusion in an experimental model of septic shock induced by intravenous inoculation with live Escherichia coli. Anesthetized dogs received an intravenous infusion of 1.2 x 10(10) cfu/kg live E. coli in 30 min. After 30 min of observation, they were randomized to controls (no fluids; N = 7), or fluid resuscitation with lactated Ringer's solution, 16 ml/kg (N = 7) or 32 ml/kg (N = 7) over 30 min and followed for 120 min. Cardiac index, portal blood flow, mean arterial pressure, systemic and regional oxygen-derived variables, blood lactate, and gastric PCO2 were assessed. Rapid and progressive cardiovascular deterioration with reduction in cardiac output, mean arterial pressure and portal blood flow (approximately 50, approximately 25 and approximately 70%, respectively) was induced by the live bacteria challenge. Systemic and regional territories showed significant increases in oxygen extraction and in lactate levels. Significant increases in venous-arterial (approximately 9.6 mmHg), portal-arterial (approximately 12.1 mmHg) and gastric mucosal-arterial (approximately 18.4 mmHg) PCO2 gradients were also observed. Early fluid replacement, especially with 32 ml/kg volumes of crystalloids, promoted only partial and transient benefits such as increases of approximately 76% in cardiac index, of approximately 50% in portal vein blood flow and decreases in venous-arterial, portal-arterial, gastric mucosal-arterial PCO2 gradients (7.2 +/- 1.0, 7.2 +/- 1.3 and 9.7 +/- 2.5 mmHg, respectively). The fluid infusion promoted only modest and transient benefits, unable to restore the systemic and regional perfusional and metabolic changes in this hypodynamic septic shock model. PMID:15933781

  15. XAFS of short-lived reduction products of structural and functional models of the [Fe Fe] hydrogenase H-cluster

    NASA Astrophysics Data System (ADS)

    Bondin, Mark I.; Borg, Stacey J.; Cheah, Mun-Hon; Best, Stephen P.

    2006-11-01

    Thiolate-bridged diiron compounds that are related to the active site of the [Fe-Fe] hydrogenase enzyme have been shown to act as electrocatalysts for reduction of protons. The use of XAFS for clarification of the structures of intermediates formed following reduction of related diiron carbonyl compounds is described. These measurements allow the determination of Fe-Fe and Fe-S bond lengths with good reliability and when used in conjunction with the standard bonding models this provides a means of validating the structures proposed for longer-lived ( t>20 s at -50 C) reaction intermediates.

  16. Detection of the short-lived radical cation intermediate in the electrooxidation of N,N-dimethylaniline by mass spectrometry.

    PubMed

    Brown, Timothy A; Chen, Hao; Zare, Richard N

    2015-09-14

    The N,N-dimethylaniline (DMA) radical cation DMA(.+) , a long-sought transient intermediate, was detected by mass spectrometry (MS) during the electrochemical oxidation of DMA. This was accomplished by coupling desorption electrospray ionization (DESI) MS with a waterwheel working electrode setup to sample the surface of the working electrode during electrochemical analysis. This study clearly shows that DESI-based electrochemical MS is capable of capturing electrochemically generated intermediates with half-lives on the order of microseconds, which is 4-5 orders of magnitude faster than previously reported electrochemical mass spectrometry techniques. PMID:26352029

  17. Metabolic adaptations to short-term every-other-day feeding in long-living Ames dwarf mice

    PubMed Central

    Brown-Borg, Holly M.; Rakoczy, Sharlene

    2013-01-01

    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

  18. Short-lived species detection of nitrous acid by external-cavity quantum cascade laser based quartz-enhanced photoacoustic absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Yi, Hongming; Maamary, Rabih; Gao, Xiaoming; Sigrist, Markus W.; Fertein, Eric; Chen, Weidong

    2015-03-01

    Spectroscopic detection of short-lived gaseous nitrous acid (HONO) at 1254.85 cm-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 mm3) 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 × 10-8 cm-1 W/Hz1/2. 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 × 10-7 cm-1 (MDL ˜ 3 ppbv) in 1 s and ˜1.1 × 10-8 cm-1 (MDL ˜ 330 pptv) in 150 s, respectively, with 1 W laser power.

  19. 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.

  20. Involvement of the molecular chaperone Ydj1 in the ubiquitin-dependent degradation of short-lived and abnormal proteins in Saccharomyces cerevisiae.

    PubMed Central

    Lee, D H; Sherman, M Y; Goldberg, A L

    1996-01-01

    In Escherichia coli and mitochondria, the molecular chaperone DnaJ is required not only for protein folding but also for selective degradation of certain abnormal polypeptides. Here we demonstrate that in the yeast cytosol, the homologous chaperone Ydj1 is also required for ubiquitin-dependent degradation of certain abnormal proteins. The temperature-sensitive ydj1-151 mutant showed a large defect in the overall breakdown of short-lived cell proteins and abnormal polypeptides containing amino acid analogs, especially at 38 degrees C. By contrast, the degradation of long-lived cell proteins, which is independent of ubiquitin, was not altered nor was cell growth affected. The inactivation of Ydj1 markedly reduced the rapid, ubiquitin-dependent breakdown of certain beta-galactosidase (beta-gal) fusion polypeptides. Although degradation of N-end rule substrates (arginine-beta-gal and leucine-beta-gal) and the B-type cyclin Clb5-beta-gal occurred normally, degradation of the abnormal polypeptide ubiquitin-proline-beta-gal (Ub-P-beta-gal) and that of the short-lived normal protein Gcn4 were inhibited. As a consequence of reduced degradation of Ub-P-beta-gal, the beta-gal activity was four to five times higher in temperature-sensitive ydj1-151 mutant cells than in wild-type cells; thus, the folding and assembly of this enzyme do not require Ydj1 function. In wild-type cells, but not in ydj1-151 mutant cells, this chaperone is associated with the short-lived substrate Ub-P-beta-gal and not with stable beta-gal constructs. Furthermore, in the ydj1-151 mutant, the ubiquitination of Ub-P-beta-gal was blocked and the total level of ubiquitinated protein in the cell was reduced. Thus, Ydj1 is essential for the ubiquitin-dependent degradation of certain proteins. This chaperone may facilitate the recognition of unfolded proteins or serve as a cofactor for certain ubiquitin-ligating enzymes. PMID:8756635

  1. 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.

  2. 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.

  3. "Unattached" fraction of short-lived Rn decay products in indoor and outdoor environments: an improved single-screen method and results.

    PubMed

    Reineking, A; Porstendörfer, J

    1990-06-01

    The unattached fraction fp of potential alpha energy of short-lived Rn decay products was measured under realistic, natural conditions in different dwellings and in the open atmosphere by a single-screen technique. An improved data evaluation method was developed where the measured activities of 218Po (RaA) and 214Pb (RaB) were corrected by the screen-attached activities of 214Bi (214Po) [RaC (RaC')]. This method is based on the experimental observation that the 214Bi (214Po) unattached activities are negligible under realistic living conditions and that the size distributions of the aerosol-attached activities of all short-lived Rn daughters are identical. In closed rooms without additional aerosol sources, a mean unattached fraction fp of the potential alpha energy of 0.096 was obtained at a mean aerosol particle concentration of 6100 cm-3 and at a mean equilibrium factor F of 0.30. This mean fp value is about three times higher than the value used in the literature for the radiation exposure calculation of the human public. In closed rooms with additional aerosol sources (cigarette smoke, heating systems, aerosols from a burning candle), the aerosol particle concentrations ranged up to 10(6) cm-3 and the attachment rates, X, increased up to 1000 h-1. The fp values sometimes decreased below the detection limit of 0.005, and the F values increased to as high as 0.77. In the ambient atmosphere in the vicinity of Göttingen, a mean unattached fraction fp of 0.02 and a mean aerosol particle concentration of 3.4 x 10(4) cm-3 were measured at 1 m above the ground. The mean equilibrium factor F was determined to be 0.7. PMID:2160922

  4. Effective Strategy for Conformer-Selective Detection of Short-Lived Excited State Species: Application to the IR Spectroscopy of the N1H Keto Tautomer of Guanine.

    PubMed

    Asami, Hiroya; Tokugawa, Munefumi; Masaki, Yoshiaki; Ishiuchi, Shun-Ichi; Gloaguen, Eric; Seio, Kohji; Saigusa, Hiroyuki; Fujii, Masaaki; Sekine, Mitsuo; Mons, Michel

    2016-04-14

    The ultrafast deactivation processes in the excited state of biomolecules, such as the most stable tautomers of guanine, forbid any state-of-the-art gas phase spectroscopic studies on these species with nanosecond lasers. This drawback can be overcome by grafting a chromophore having a long-lived excited state to the molecule of interest, allowing thus a mass-selective detection by nanosecond R2PI and therefore double resonance IR/UV conformer-selective spectroscopic studies. The principle is presently demonstrated on the keto form of a modified 9-methylguanine, for which the IR/UV double resonance spectrum in the C═O stretch region, reported for the first time, provides evidence for extensive vibrational couplings within the guanine moiety. Such a successful strategy opens up a route to mass-selective IR/UV spectroscopic investigations on molecules exhibiting natural chromophores having ultrashort-lived excited states, such as DNA bases, their complexes as well as peptides containing short-lived aromatic residues. PMID:26990184

  5. Temperate carbonate debrites and short-lived earliest Miocene yo-yo tectonics, eastern Taranaki Basin margin, New Zealand

    NASA Astrophysics Data System (ADS)

    Hood, Steven D.; Nelson, Campbell S.

    2012-03-01

    This study examines two unconformity-bound earliest Miocene temperate shallow-marine limestones at remote Gibson Beach, western North Island, on the eastern margin of Taranaki Basin, New Zealand's only producing hydrocarbon province. The local geology comprises an upper limestone of up to 6 m of spectacular conglomeratic limestone (rudstone; Papakura Limestone) whose pebble- to boulder-sized clasts were derived from cannibalisation of the lower skeletal limestone (bryomol grainstone; Otorohanga Limestone). Multiple lines of evidence require the Otorohanga Limestone to have been well indurated before erosion and clast generation. Cementation occurred from pressure dissolution of calcitic skeletons at burial depths of probably 400 m or more. Subsequent uplift led to local subaerial exposure and karstification of a fault-block cliffed coastline where physical erosion sourced talus limestone debris onto adjacent high-energy pocket beaches. Storm and/or seismic events periodically triggered mass flows of the limestone clasts offshore onto the contemporary mixed siliciclastic-carbonate shelf as channelised carbonate debrites. Lithification of these Papakura Limestone debrites occurred via pressure dissolution, and required a second burial episode. Karst pinnacles preserved on the eroded upper surface of the Papakura Limestone demand uplift again and erosion in a subaerial setting, before subsequent deep burial by Early Miocene siliciclastic shelf sand and turbidite deposits. Strontium isotope dating of brachiopod fossils suggests the two postulated burial-uplift cycles, involving movements up to 400 ± 100 m, occurred very rapidly within several 100 kyr. Speculative drivers of the yo-yo tectonic events are earliest Miocene movements on the nearby major Taranaki Fault thrust in association with regional changes in subduction tectonics at the Australian-Pacific plate boundary, along with pulsed emplacement of obducted gravity slide deposits (Northland Allochthon) onto northern North Island. The two limestones record a previously undocumented degree of eastern Taranaki Basin margin tectonic mobility relevant to a fuller appreciation of petroleum system development in that basin.

  6. Seasonal and Short-term Variation of Water Vapor Isotope ratios in Surface Air in Sapporo, Japan

    NASA Astrophysics Data System (ADS)

    Sunmonu, L. A.; Fujiyoshi, Y.; Muramoto, K.; Kurita, N.

    2011-12-01

    Stable isotopes of atmospheric water vapor provide information about movement of water and its phase changes in the atmosphere. Surface water vapor's δD and δ18O measurement was conducted in Sapporo (43.1N, 141.3E), a humid continental site characterized by a warm but not humid summer and a quite cold and snowy winter, in Hokkaido, Japan with a Los Gatos Research's (LGR) Water-Vapor Isotope Analyzer (WVIA, model DLT-100). The observation in Sapporo was carried out in four phases: (I) 28 April 2009 - 25 June 2009; (II) 15 September 2009 - 29 November 2009; (III) 1 April 2010 - 21 May 2010 and (IV) 17 December 2010 - 30 May 2011. In addition, auxiliary data (air temperature, atmospheric pressure, relative humidity, wind speed & direction, etc.) were obtained with an automatic weather station (AWS). Thus, the objective of this study is to investigate the characteristics of δD and δ18O of atmospheric water vapor near the ground in Sapporo and to explore the meteorological processes that influence δD and δ18O of atmospheric water vapor at the surface. In general, δD and δ18O were higher in warm season (PHASES I & III) than in cold season (PHASES II & IV) with almost equal day-to-day δD variability in both seasons. The lightest δD (-239.7%) occurs in the month of March/April despite not being the coldest month in Sapporo. This is thought to be due to "rigorous" evaporation due to snow-melting. In addition, over periods of about 1-7days, considerable variations occurred, sometimes exceeding 100% for δD. These considerable variations were attributable to weather phenomena such as sea-breeze and cold frontal passages. The former causes δD to increase abruptly while the latter causes an abrupt decrease.

  7. 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. PMID:25074859

  8. 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

  9. 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.

  10. Within-individual plasticity explains age-related decrease in stress response in a short-lived bird.

    PubMed

    Lendvai, dm Z; Giraudeau, Mathieu; Bkony, Veronika; Angelier, Frdric; Chastel, Olivier

    2015-07-01

    A crucial problem for every organism is how to allocate energy between competing life-history components. The optimal allocation decision is often state-dependent and mediated by hormones. Here, we investigated how age, a major state variable affects individuals' hormonal response to a standardized stressor: a trait that may reflect allocation between self-maintenance and reproduction. We caught free-living house sparrows and measured their hormonal (corticosterone) response to capture stress in consecutive years. Using a long-term ringing dataset, we determined the age of the birds, and we partitioned the variation into within- and among-individual age components to investigate the effects of plasticity versus selection or gene flow, respectively, on the stress response. We found large among-individual variation in the birds' hormone profiles, but overall, birds responded less strongly to capture stress as they grew older. These results suggest that stress responsiveness is a plastic trait that may vary within individuals in an adaptive manner, and natural selection may act on the reaction norms producing optimal phenotypic response in the actual environment and life-history stage. PMID:26179799

  11. 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.

  12. 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

  13. Highly efficient luminescence of Cu(I) compounds: thermally activated delayed fluorescence combined with short-lived phosphorescence.

    PubMed

    Hofbeck, Thomas; Monkowius, Uwe; Yersin, Hartmut

    2015-01-14

    Luminescent materials showing thermally activated delayed fluorescence (TADF) have gained high attractiveness as emitters in organic light emitting diodes (OLEDs) and other photonic applications. Nevertheless, even utilization of TADF can be further improved, introducing a novel concept. This is demonstrated by a new class of brightly luminescent low-cost Cu(I) compounds, for which the emission stems from both the lowest excited triplet T1 and singlet S1 state. At T = 300 K, these materials exhibit quantum yields of more than ΦPL = 90% at short emission decay times. About 80% of the emission intensity stems from the singlet due to TADF, but importantly, an additional 20% is contributed by the lower lying triplet state according to effective spin-orbit coupling (SOC). SOC induces also a relatively large zero-field splitting of the triplet being unusual for Cu(I) complexes. Thus, the overall emission decay time is distinctly reduced. Combined use of both decay paths opens novel photonic applications, in particular, for OLEDs. PMID:25486064

  14. Gold-195m, an ultra-short-lived generator-produced radionuclide: clinical application in sequential first pass ventriculography.

    PubMed

    Mena, I; Narahara, K A; de Jong, R; Maublant, J

    1983-02-01

    Gold 195m (Au-195m) has a half-life of 30.5 sec and can be produced at the bedside from the parent mercury-195m (T 1/2 = 41.6 hr). The generator produced sterile pyrogen-free Au-195m with mercury breakthrough of 0.75 +/- 0.09 (s.e.m.) muCi per mCi of Au-195m. Approximately 20 to 25 mCi of Au-195m was produced per elution from a generator containing 155 mCi of Hg-195m. We compared first-pass resting Tc-99m angiograms with Au-195m angiograms in 28 patients. The correlation coefficient between the two studies was 0.92 over an ejection-fraction range from 0.22 to 0.83. In addition, we tested the reproducibility of Au-195m first-pass angiograms by performing two studies 3 min apart. In 25 patients with ejection fractions ranging from 0.20 to 0.78, the correlation coefficient between such pairs was 0.93. The nuclide is reliably and reproducibly produced, and its short half-life allows the performance of background-free sequential first-transit studies with unusually low radiation exposure to the patient. PMID:6296336

  15. 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

  16. 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

  17. 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 0.62 (95%CI, 0.34 – 0.80) to 0.73 (95%CI, 0.50 – 0.86) indicating fair to good reliability. The raw score MDC was 6.12. Conclusion The BOT-2 Short Form has acceptable reliability for use in remote Australian Aboriginal communities and will be useful in determining motor deficits in children exposed to alcohol prenatally. This is the first known study evaluating the reliability of the BOT-2 Short Form, either in the context of assessment for FASD or in Aboriginal children. PMID:24010634

  18. PCR in situ: a rapid alternative to in situ hybridization for mapping short, low copy number sequences without isotopes.

    PubMed

    Gosden, J; Hanratty, D

    1993-07-01

    A new technique for rapid localization of short, low copy number sequences is described, which uses a form of PCR on preparations of fixed metaphase chromosomes on microscope slides, with the temperature cycling controlled by a flatbed thermal cycler. In its present form, the method is capable of detecting very low copy number sequences, and further development is expected to achieve the target of localizing unique sequences. It has advantages over conventional fluorescent in situ hybridization, both in the speed (easily complete within a work-day) and in the potential sensitivity. PMID:8363841

  19. 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.

  20. The Effect of Observers’ Mood on the Local Processing of Emotional Faces: Evidence from Short-Lived and Prolonged Mood States

    PubMed Central

    Mokhtari, Setareh; Buttle, Heather

    2015-01-01

    We examined the effect of induced mood, varying in valence and longevity, on local processing of emotional faces. It was found that negative facial expression conveyed by the global level of the face interferes with efficient processing of the local features. The results also showed that the duration of involvement with a mood influenced the local processing. We observed that attending to the local level of faces is not different in short-lived happy and sad mood states. However, as the mood state is experienced for a longer period, local processing was impaired in happy mood compared to sad mood. Taken together, we concluded that both facial expressions and affective states influence processing of the local parts of faces. Moreover, we suggest that mediating factors like the duration of involvement with the mood play a role in the interrelation between mood, attention, and perception. PMID:25883696

  1. DIFFERENCES AND SIMILARITIES IN ANDRA'S ASSESSMENT OF ACTIVITIES CARRIED OUT BY RADIOACTIVE WASTE GENERATORS AND AFFECTING THE QUALITY OF IL-LL SHORT-LIVED WASTE PACKAGES AND HL-IL LONG-LIVED WASTE PACKAGES

    SciTech Connect

    Trentesaux, C.; Cairon, P.; Dumont, J.-N.; Felix, B.; Losada, F.

    2003-02-27

    In both cases of packages for either low-level and intermediate-level short-lived (LL-IL/SL) or high-level and intermediate-level long-lived (HL-IL/LL) radioactive waste, Andra has defined a quality reference system, manages it, follows up its appropriate implementation in production plants and verifies its effectiveness in production. The purpose of such a reference system is to ensure, in the first case, that waste packages comply with the Centre de l'Aube's acceptance criteria and, in the second case, that the characteristics submitted by the waste generators to Andra as input data for the deep geological repository project reflect the actual production conditions. In that context, the three management steps of the quality reference system include differences due to the fact that HL-IL/SL packages have not been submitted yet to any technical acceptance criterion. Compliance with any such criterion should be the subject of a characterization report during the qualification phase and of a examination during the verification phase. The management of the quality reference system also involves similarities that facilitate the joint work carried out by Andra with the waste generators, especially in the facilities where both package types are produced.

  2. 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 plants were of generally high quality in terms of insect performance. We discuss ecological and evolutionary constraints on insects that must search in new habitats for different plant species over successive generations. PMID:24028469

  3. 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.

  4. Forcing switch from short- to intermediate- and long-lived states of the alphaA domain generates LFA-1/ICAM-1 catch bonds.

    PubMed

    Chen, Wei; Lou, Jizhong; Zhu, Cheng

    2010-11-12

    Binding of lymphocyte function-associated antigen-1 (LFA-1) to intercellular adhesion molecule-1 (ICAM-1) mediates leukocyte adhesion under force. Using a biomembrane force probe capable of measuring single bond interactions, we showed ICAM-1 binding to LFA-1 at different conformations, including the bent conformation with the lowest affinity. We quantify how force and conformations of LFA-1 regulate its kinetics with ICAM-1. At zero-force, on-rates were substantially changed by conditions that differentially favor a bent or extended LFA-1 with a closed or open headpiece; but off-rates were identical. With increasing force, LFA-1/ICAM-1 bond lifetimes (reciprocal off-rates) first increased (catch bonds) and then decreased (slip bonds). Three states with distinct off-rates were identified from lifetime distributions. Force shifted the associated fractions from the short- to intermediate- and long-lived states, producing catch bonds at low forces, but increased their off-rates exponentially, converting catch to slip bonds at high forces. An internal ligand antagonist that blocks pulling of the α(7)-helix suppressed the intermediate-/long-lived states and eliminated catch bonds, revealing an internal catch bond between the αA and βA domains. These results elucidate an allosteric mechanism for the mechanochemistry of LFA-1/ICAM-1 binding. PMID:20819952

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

    NASA Astrophysics Data System (ADS)

    Barber, R. C.; de Laeter, J. R.

    2009-04-01

    In their article “Existence of Long-Lived Isomeric States in Naturally-Occuring Neutron-Deficient Th Isotopes” [Phys. Rev. C 76, 021303 (2007)], Marinov fail to demonstrate that basic mass spectrometric protocols, such as abundance sensitivity, linearity, and freedom from possible interferences, have been met. In particular, the claim that four isomeric states of Th have been discovered, using an inductively coupled plasma-sector field mass spectrometer (ICP-SFMS), with abundances from (1-10)×10-11 relative to Th232, cannot be accepted, given the known abundance sensitivities of other sector field mass spectrometers. Accelerator mass spectrometry is the only mass spectrometric methodology capable of measuring relative abundances of the magnitude claimed by Marinov

  6. 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. PMID:25405926

  7. 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-Pags, 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 (26C), 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. ?13C 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 (C27?5) was also directly acquired from the food. Thermal stress (31C) 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 ?13C 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.

  8. 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 region, photochemical processing and transport timescales of an air mass. Seasonal and longer-term trends in trace gases and trace gas composition are discussed, as well as composition of air masses having different origins. Additionally, we apply relationships between the different species, particularly the NMHC, to gain a qualitative understanding of photochemical processes occurring during transport from the boundary layer to the upper troposphere over Europe.

  9. IN-SITU RADIONUCLIDE TRANSPORT NEAR THE NOPAL I URANIUM DEPOSIT AT PENA BLANCA, MEXICO: CONSTRAINTS FROM SHORT-LIVED DECAY-SERIES RADIONUCLIDES

    SciTech Connect

    S. Luo; T.L. Ku; V. Todd; M. Murrell; J. Alfredo Rodriguez Pineda; J. Dinsmoor; A. Mitchell

    2005-07-11

    For nuclear waste management, an important mechanism by which radioactive waste components are isolated from returning to the human environment, the biosphere, is by the geological barrier in which the effectiveness of the barrier is characterized by in-situ retardation factor, i.e., the transport rate of a radionuclide relative to that of groundwater. As part of natural analog studies of the Yucca Mountain Project of the U. S. Department of Energy, we propose such characterization by using naturally-occurring decay-series radioisotopes as an analog. We collected large-volume (>1000 liters) groundwater samples from three wells (PB, Pozos, and PB4, respectively) near the Nopal I Uranium Ore site at Pena Blanca, Mexico, by using an in-situ Mn-cartridge filtration technique for analysis of short-lived decay-series radionuclides. Results show that the activities of short-lived radioisotopes ({sup 228}Ra, {sup 224}Ra and {sup 223}Ra) and activity ratios of {sup 224}Ra/{sup 228}Ra and {sup 224}Ra/{sup 223}Ra are higher at PB and Pozos than at PB4. In contrast, the {sup 210}Po activity is much lower at PB and Pozos than at PB4. The high Ra activities and activities ratios at PB and Pozos are attributable to the high alpha-recoil input from the aquifer rocks, while the high {sup 210}Po activity at PB4 is due to the enhanced colloidal transport. Based on a uranium-series transport model, we estimate that the in-situ retardation factor of Ra is (0.43 {+-} 0.02) x 10{sup 3} at PB, (1.68 {+-} 0.08) x 10{sup 3} at Pozos, and (1.19 {+-} 0.08) x 10{sup 3} at PB4 and that the mean fracture width in the aquifer rocks is about 0.23 {micro}m at PB, 0.37 {micro}m at Posos, and 4.0 {micro}m at PB4, respectively. The large fracture width at PB4 as derived from the model provides an additional evidence to the inference from the Po measurements that particle-reactive radionuclides are transported mainly as colloidal forms through the large fractures in rocks. Our model also suggests that in addition to alpha recoil, decay of {sup 226}Ra from the adsorbed phases also contributes a significant source of {sup 222}Rn to groundwater. It appears that the information obtained from this study provides useful testing and validation for the Yucca Mountain total system performance assessment model (TSPA).

  10. 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.

  11. 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.

  12. 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).

  13. Carbon isotope compositions (?(13) C) of leaf, wood and holocellulose differ among genotypes of poplar and between previous land uses in a short-rotation biomass plantation.

    PubMed

    Verlinden, M S; Fichot, R; Broeckx, L S; Vanholme, B; Boerjan, W; Ceulemans, R

    2015-01-01

    The efficiency of water use to produce biomass is a key trait in designing sustainable bioenergy-devoted systems. We characterized variations in the carbon isotope composition (?(13) C) of leaves, current year wood and holocellulose (as proxies for water use efficiency, WUE) among six poplar genotypes in a short-rotation plantation. Values of ?(13) Cwood and ?(13) Cholocellulose were tightly and positively correlated, but the offset varied significantly among genotypes (0.79-1.01). Leaf phenology was strongly correlated with ?(13) C, and genotypes with a longer growing season showed a higher WUE. In contrast, traits related to growth and carbon uptake were poorly linked to ?(13) C. Trees growing on former pasture with higher N-availability displayed higher ?(13) C as compared with trees growing on former cropland. The positive relationships between ?(13) Cleaf and leaf N suggested that spatial variations in WUE over the plantation were mainly driven by an N-related effect on photosynthetic capacities. The very coherent genotype ranking obtained with ?(13) C in the different tree compartments has some practical outreach. Because WUE remains largely uncoupled from growth in poplar plantations, there is potential to identify genotypes with satisfactory growth and higher WUE. PMID:24906162

  14. Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

    NASA Astrophysics Data System (ADS)

    Monks, P. S.; Archibald, A. T.; Colette, A.; Cooper, O.; Coyle, M.; Derwent, R.; Fowler, D.; Granier, C.; Law, K. S.; Stevenson, D. S.; Tarasova, O.; Thouret, V.; von Schneidemesser, E.; Sommariva, R.; Wild, O.; Williams, M. L.

    2014-12-01

    Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a by-product of the very oxidation chemistry it largely initiates. Much effort is focussed on the reduction of surface levels of ozone owing to its health impacts but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve due to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate-change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner.

  15. Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

    NASA Astrophysics Data System (ADS)

    Monks, P. S.; Archibald, A. T.; Colette, A.; Cooper, O.; Coyle, M.; Derwent, R.; Fowler, D.; Granier, C.; Law, K. S.; Mills, G. E.; Stevenson, D. S.; Tarasova, O.; Thouret, V.; von Schneidemesser, E.; Sommariva, R.; Wild, O.; Williams, M. L.

    2015-08-01

    Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. Much effort is focused on the reduction of surface levels of ozone owing to its health and vegetation impacts, but recent efforts to achieve reductions in exposure at a country scale have proved difficult to achieve owing to increases in background ozone at the zonal hemispheric scale. There is also a growing realisation that the role of ozone as a short-lived climate pollutant could be important in integrated air quality climate change mitigation. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. It takes the view that knowledge across the scales is important for dealing with air quality and climate change in a synergistic manner. The review shows that there remain a number of clear challenges for ozone such as explaining surface trends, incorporating new chemical understanding, ozone-climate coupling, and a better assessment of impacts. There is a clear and present need to treat ozone across the range of scales, a transboundary issue, but with an emphasis on the hemispheric scales. New observational opportunities are offered both by satellites and small sensors that bridge the scales.

  16. Two promising future developments of cryo-EM: capturing short-lived states and mapping a continuum of states of a macromolecule.

    PubMed

    Chen, Bo; Frank, Joachim

    2016-02-01

    The capabilities and application range of cryogenic electron microscopy (cryo-EM) method have expanded vastly in the last two years, thanks to the advances provided by direct detection devices and computational classification tools. We take this review as an opportunity to sketch out promising developments of cryo-EM in two important directions: (i) imaging of short-lived states (10-1000 ms) of biological molecules by using time-resolved cryo-EM, particularly the mixing-spraying method and (ii) recovering an entire continuum of coexisting states from the same sample by employing a computational technique called manifold embedding. It is tempting to think of combining these two methods, to elucidate the way the states of a molecular machine such as the ribosome branch and unfold. This idea awaits further developments of both methods, particularly by increasing the data yield of the time-resolved cryo-EM method and by developing the manifold embedding technique into a user-friendly workbench. PMID:26520784

  17. 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

  18. 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

  19. Properties of the short-lived triplet states of pyridazine and 3,6-dichloropyridazine studied by a time-resolved EPR method

    NASA Astrophysics Data System (ADS)

    Terazima, Masahide; Yamauchi, Seigo; Hirota, Noboru

    1986-04-01

    The magnetic and decay properties of the short-lived triplet (T1) states of pyridazine and 3,6-dichloropyridazine (DCP) were studied by means of time-resolved EPR with laser excitation. The zfs of DCP in the p-dibromobenzene (DBB) host are X=0.094 cm-1, Y=-0.164 cm-1, and Z=0.070 cm-1, and the nitrogen hfcc are Ax=27 G, Ay=18 G, and Az=25 G, which confirms the nπ* character of the T1 state. Similar zfs were obtained for DCP and pyridazine in other environments. The sublevel decay rate constants and the relative populating rates were determined from the analysis of the transient EPR signals measured at 3.0 K where the effect of the spin lattice relaxation can be neglected. It was found in both systems that ky is much greater than kx, kz as predicted by a simple group theoretical consideration. ky of DCP and pyridazine were determined to be on the order of 106 s-1, being larger than that of pyrimidine by a factor of ˜104. The reasons for the large ky are discussed, particularly, in terms of the distorted potential of the T1 state.

  20. Repeatability and validation of a short, semi-quantitative food frequency questionnaire designed for older adults living in Mediterranean areas: the MEDIS-FFQ.

    PubMed

    Tyrovolas, Stefanos; Pounis, George; Bountziouka, Vassiliki; Polychronopoulos, Evangelos; Panagiotakos, Demosthenes B

    2010-07-01

    The aim of the present work was to evaluate the repeatability and the validity of a short food frequency questionnaire (FFQ) that could be used for older people living in Mediterranean areas. The semi-quantitative FFQ included questions regarding the frequency of consumption of the main food groups and beverages typically consumed in the Mediterranean areas as well as some questions regarding eating habits of older persons. During 2006-2007, for the repeatability assessment (within 10-30 days), 150 individuals (51 +/- 17 yrs, 40% males) were studied, while another 190 individuals (74 +/- 9 yrs, 52% males) were enrolled for the validation purposes. Agreement of the FFQ with the 3-day food records was evaluated using the Bland-Altman method and the Kendall's tau-b coefficient. Repeatability was tested using the Cohen's kappa coefficient. Between 3-day food records and the FFQ, good agreement for alcohol (tau-b = 0.64, p < 0.001) was found, while moderate agreement for food and beverage groups of greens (tau-b = 0.32, p < 0.001), fruits (tau-b = 0.35, p < 0.001), cereals (tau-b = 0.61, p < 0.001), sweets (tau-b = 0.51, p < 0.001), and coffee (tau-b = 0.58, p < 0.001) was observed. Low, but still significant, agreement for fish (tau-b = 0.21, p = 0.001), legumes (tau-b = 0.23, p < 0.001), vegetables (tau-b = 0.23, p < 0.001), pasta (tau-b = 0.25, p < 0.001), potatoes (tau-b = 0.17, p = 0.006) and meat consumption (tau-b = 0.14, p < 0.001) were also found. The FFQ was also valid regarding the estimation of macronutrients and energy intake. Sensitivity analyses by sex, age category ( 75 yrs), and education status showed similar validity of the FFQ in each subgroup, except for elders older than 75 years. The repeatability of the FFQ was fair in all foods tested (Cohen's kappa coefficients varied between 0.15-0.39, p-values < 0.05). The suggested FFQ seems to be a reasonably valid and repeatable measure of dietary intake and can be used in older persons living in the Mediterranean areas. PMID:20711925

  1. Carbon isotope discrimination of C3 vegetation in Central Asian grassland as related to long-term and short-term precipitation patterns

    NASA Astrophysics Data System (ADS)

    Wittmer, M. H. O. M.; Auerswald, K.; Tungalag, R.; Bai, Y. F.; Schufele, R.; Schnyder, H.

    2008-06-01

    The relationship between carbon isotope discrimination (13?) of C3 vegetation and long-term (30 years) and short-term (growing period) precipitation was investigated. Different species of Stipa, a dominant grass genus in the (semi-)arid Asian steppes, and other C3 species were collected along aridity gradients in Inner Mongolia in 2005 (11 sites, 71 samples) and in the Republic of Mongolia in 2006 (40 sites, 45 samples). The data set was expanded with published and unpublished data of Stipa and other C3 species (11 studies covering 8 years, including 64 observations of Stipa, and 103 observations of other C3 species) and C3 community bulk-samples (11 samples). Weather data were geostatistically interpolated for all sampling sites and years. 13? of Stipa followed different relationships for the individual years when related to mean annual precipitation due to large anomalies between annual and long-term average precipitation patterns. However, the 13? response to rainfall converged when the (long-term) mean annual precipitation was replaced by year-specific mean daily precipitation during the growing period (PG). Remarkably, the 13?-response to (PG) for C3 species as a whole (including herbaceous dicots, semi-shrubs and grasses) and also the C3 community-level response were virtually identical to that of Stipa. The relation was also valid outside the geographical and climatic range where it was developed, giving proof of its robustness.

  2. An isotope-labeled chemical derivatization method for the quantitation of short-chain fatty acids in human feces by liquid chromatography-tandem mass spectrometry.

    PubMed

    Han, Jun; Lin, Karen; Sequeira, Carita; Borchers, Christoph H

    2015-01-01

    Short-chain fatty acids (SCFAs) are produced by anaerobic gut microbiota in the large bowel. Qualitative and quantitative measurements of SCFAs in the intestinal tract and the fecal samples are important to understand the complex interplay between diet, gut microbiota and host metabolism homeostasis. To develop a new LC-MS/MS method for sensitive and reliable analysis of SCFAs in human fecal samples, 3-nitrophenylhydrazine (3NPH) was employed for pre-analytical derivatization to convert ten C2-C6 SCFAs to their 3-nitrophenylhydrazones under a single set of optimized reaction conditions and without the need of reaction quenching. The derivatives showed excellent in-solution chemical stability. They were separated on a reversed-phase C18 column and quantitated by negative-ion electrospray ionization - multiple-reaction monitoring (MRM)/MS. To achieve accurate quantitation, the stable isotope-labeled versions of the derivatives were synthesized in a single reaction vessel from (13)C6-3NPH, and were used as internal standard to compensate for the matrix effects in ESI. Method validation showed on-column limits of detection and quantitation over the range from low to high femtomoles for the ten SCFAs, and the intra-day and inter-day precision for determination of nine of the ten SCFAs in human fecal samples was ≤8.8% (n=6). The quantitation accuracy ranged from 93.1% to 108.4% (CVs≤4.6%, n=6). This method was used to determine the SCFA concentrations and compositions in six human fecal samples. One of the six samples, which was collected from a clinically diagnosed type 2 diabetes patient showed a significantly high molar ratio of branch-chain SCFAs to straight-chain SCFAs than the others. In summary, this work provides a new LC-MS/MS method for precise and accurate quantitation of SCFAs in human feces. PMID:25479871

  3. Studying the decay phase of a short-lived active region with coordinated DST/IBIS, Hinode/EIS+SOT+XRT, SOHO/MDI and TRACE observations

    NASA Astrophysics Data System (ADS)

    Zuccarello, F.; Berrilli, F.; Centrone, M.; Contarino, L.; Criscuoli, S.; Del Moro, D.; Ermolli, I.; Giorgi, F.; Guglielmino, L. S.; Salerno, C.; Spadaro, D.; Romano, P.

    2008-09-01

    This study concerns the physical processes occurring during the decay phase of the short-lived active region NOAA 10977, as evaluated from analysis of data gathered using ground- (DST/IBIS) and space-based (Hinode/EIS+SOT+XRT, SOHO/MDI and TRACE) facilities. The coordinated observing campaign was performed from December 1st to 9th, 2007, covering several spectral ranges, with unprecedented spatial and spectral resolution. We present preliminary results of the Doppler analysis of plasma motions evaluated from monochromatic images taken along the Ca II (8542 Å) and the Fe I (7049 Å) spectral lines with IBIS. We also report results concerning the horizontal displacements of photospheric magnetic structures and advection flows as obtained from application of Local Correlation Tracking (LCT) and Two-Level Structure Tracking (TST) techniques to both the LoS magnetograms taken by MDI and to high resolution intensity maps obtained by IBIS at DST/NSO. Further contributions to understanding the mechanisms at the base of the magnetic field diffusion are provided from the inversion of the Stokes profiles of the photospheric Fe I lines at 6301.5 Å and 6302.5 Å, obtained with SOT/SP, and the analysis of filtergrams in the core of the Ca II H line (3968.5 ± 3 Å) and images in G-band (4305 ± 8 Å) taken by SOT/BFI, as well as EIS data and images taken by the thin Be of XRT, and by TRACE at 171 Å and 1600 Å.

  4. 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

  5. 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.

  6. Contributions of short-lived radioiodines to thyroid doses received by evacuees from the Chernobyl area estimated using early in vivo activity measurements.

    PubMed

    Balonov, M; Kaidanovsky, G; Zvonova, I; Kovtun, A; Bouville, A; Luckyanov, N; Voillequé, P

    2003-01-01

    A series of in vivo gamma spectrometric measurements of 65 people evacuated from Pripyat 1.5 days after the Chernobyl Nuclear Power Plant Unit 4 explosion was performed in St Petersburg, Russia, as early as 30 April 1986. The historical spectra and interviews were recently processed and the results used for thyroid dose estimation. Activities of 131I in thyroid and 132Te in lungs were determined easily; for estimation of 132I and 133I activities in thyroid, sophisticated methods of spectral processing were developed. According to thyroid measurement data, the mean ratio of 133I/131I activities (at the time of the accident) inhaled by residents of Pripyat was 2.0. The mean ratio of thyroid dose from 133I inhalation to that caused by 131I amounts to 0.3, which confirms the accuracy of dose estimates based on the evolution of the Chernobyl accident. The mean ratio of 132I activity in thyroid to that of 132Te in lungs was assessed from the human measurement data to be 0.2, which is in reasonable agreement with the metabolic properties of these radionuclides. The mean ratio of thyroid dose from 132I originating from 132Te deposited in lungs to the dose caused by 131I was 0.13 +/- 0.02 for Pripyat residents who did not take KI pills and 0.9 +/- 0.1 for persons who took KI pills. Thus, the contribution of short-lived radioiodines to total thyroid dose of Pripyat residents, which was on average 30% for persons who did not use stable iodine prophylaxis, and about 50% for persons who took KI pills on 26-27 April, should be accounted for in the assessment of thyroid health effects. PMID:14527033

  7. Preliminary Results of IS Plasma Focus as a Breeder of Short-Lived Radioisotopes 12C(d,n)13N

    NASA Astrophysics Data System (ADS)

    Sadat Kiai, S. M.; Elahi, M.; Adlparvar, S.; Shahhoseini, E.; Sheibani, S.; Ranjber akivaj, H.; Alhooie, S.; Safarien, A.; Farhangi, S.; Aghaei, N.; Amini, S.; Khalaj, M. M.; Zirak, A. R.; Dabirzadeh, A. A.; Soleimani, J.; Torkzadeh, F.; Mousazadeh, M. M.; Moradi, K.; Abdollahzadeh, M.; Talaei, A.; Zaeem, A. A.; Moslehi, A.; Kashani, A.; Babazadeh, A. R.; Bagiyan, F.; Ardestani, M.; Roozbahani, A.; Pourbeigi, H.; Tajik Ahmadi, H.; Ahmadifaghih, M. A.; Mahlooji, M. S.; Mortazavi, B. N.; Zahedi, F.

    2011-04-01

    Modified IS (Iranian Sun) plasma focus (10 kJ,15 kV, 94 μF, 0.1 Hz) has been used to produce the short-lived radioisotope 13N (half-life of 9.97 min) through 12C(d,n)13N nuclear reaction. The filling gas was 1.5-3 torr of hydrogen (60%) deuterium (40%) mixture. The target was solid nuclear grade graphite with 5 mm thick, 9 cm width and 13 in length. The activations of the exogenous target on average of 20 shots (only one-third acceptable) through 10-13 kV produced the 511 keV gamma rays. Another peak found at the 570 keV gamma of which both was measured by a NaI portable gamma spectrometer calibrated by a 137Cs 0.25 μCi sealed reference source with its single line at 661.65 keV and 22Na 0.1 μCi at 511 keV. To measure the gamma rays, the graphite target converts to three different phases; solid graphite, powder graphite, and powder graphite in water solution. The later phase approximately has a doubled activity with respect to the solid graphite target up to 0.5 μCi of 511 keV and 1.1 μCi of 570 keV gamma lines were produced. This increment in activity was perhaps due to structural transformation of graphite powder to nano-particles characteristic in liquid water.

  8. 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.

  9. 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. PMID:25990114

  10. RNA-seq of the aging brain in the short-lived fish N. furzeri - conserved pathways and novel genes associated with neurogenesis.

    PubMed

    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

    2014-12-01

    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

  11. 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

  12. The regulated degradation of 3-hydroxy-3-methylglutaryl-CoA reductase requires a short-lived protein and occurs in the endoplasmic reticulum.

    PubMed

    Chun, K T; Bar-Nun, S; Simoni, R D

    1990-12-15

    A chimeric gene consisting of the coding sequence for the membrane domain of the endoplasmic reticulum protein, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, fused to the coding sequence for the soluble enzyme, beta-galactosidase of Escherichia coli, has been previously constructed. This fusion protein, HMGal, has been localized to the membrane of the endoplasmic reticulum of Chinese hamster ovary cells transfected with this chimeric gene, and its beta-galactosidase activity has declined in the presence of low density lipoprotein (Skalnik, D. G., Narita, H., Kent, C., and Simoni, R. D. (1988) J. Biol. Chem. 263, 6836-6841). In this report, we demonstrate that the loss of beta-galactosidase activity results from the accelerated degradation of the HMGal protein. Taking advantage of a fluorescence-activated cell sorter technique, we have selected transfected cells which express sufficient levels of HMGal to improve its immunodetection. Based on pulse-chase experiments, the half-life of HMGal is 6.0 h, and, in the presence of 20 mM mevalonate, the half-life declines 1.7-fold. Under these conditions, mevalonate accelerates the degradation of HMG-CoA reductase in these cells 1.6-fold, from 8.4 h to 5.3 h, most probably by the same mechanism. This mevalonate-regulated degradation of HMGal is not due to a heteromeric association of HMGal with reductase, since the same effect has been observed in cells lacking the reductase protein. In addition, we demonstrate that inhibition of protein synthesis with cycloheximide abolishes the mevalonate-dependent accelerated degradation of HMGal, in agreement with previous studies which have presented indirect evidence that a short-lived protein is essential for mediating the loss of HMG-CoA reductase activity. Finally, using brefeldin A, we show that the mevalonate-dependent accelerated degradation of HMGal may occur in the endoplasmic reticulum. PMID:2254343

  13. 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. PMID:25849117

  14. Gut-Homing Conventional Plasmablasts and CD27− Plasmablasts Elicited after a Short Time of Exposure to an Oral Live-Attenuated Shigella Vaccine Candidate in Humans

    PubMed Central

    Toapanta, Franklin R.; Simon, Jakub K.; Barry, Eileen M.; Pasetti, Marcela F.; Levine, Myron M.; Kotloff, Karen L.; Sztein, Marcelo B.

    2014-01-01

    Currently, there is no licensed Shigella vaccine; however, various promising live-attenuated vaccine candidates have emerged, including CVD1208S (ΔguaBA, Δset, Δsen S. flexneri 2a), which was shown to be safe and immunogenic in Phase 1 clinical trials. Here, we report the immune responses elicited in an outpatient Phase 2 clinical trial in which subjects were vaccinated with CVD 1208S. Oral immunization with CVD 1208S elicited high anti-S. flexneri 2a LPS and IpaB antibody responses as well as an acute plasmablast (PB) infiltration in peripheral blood 7 days after immunization. PB sorted based on their expression of homing molecules confirmed that cells expressing integrin α4β7 alone or in combination with CD62L were responsible for antibody production (as measured by ELISpot). Furthermore, using high-color flow-cytometry, on day 7 after immunization, we observed the appearance of conventional PB (CPB, CD19dim CD20− CD27+high CD38+high CD3−), as well as a PB population that did not express CD27 (CD27− PB; pre-plasmablasts). The pattern of individual or simultaneous expression of homing markers (integrin α4β7, CD62L, CXCR3, and CXCR4) suggested that CPB cells homed preferentially to the inflamed gut mucosa. In contrast, ~50% CD27− PB cells appear to home to yet to be identified peripheral lymphoid organs or were in a transition state preceding integrin α4β7 upregulation. In sum, these observations demonstrate that strong immune responses, including distinct PB subsets with the potential to home to the gut and other secondary lymphoid organs, can be elicited after a short time of exposure to a shigella oral vaccine. PMID:25191323

  15. IL-2 induction of Blimp-1 is a key in vivo signal for CD8+ short-lived effector T cell differentiation.

    PubMed

    Boulet, Salix; Daudelin, Jean-Franois; Labrecque, Nathalie

    2014-08-15

    During infection or vaccination, only a small proportion of CD8(+) T cells differentiate into memory cells. The mechanisms underlying the differentiation of CD8(+) T cells into short-lived effector cells (SLECs) or memory precursor effector cells are poorly defined. It was recently shown in infectious models that the transcriptional repressor B lymphocyte-induced maturation protein 1 (Blimp-1) enhances the formation of SLECs. The factors controlling Blimp-1 expression leading to the in vivo formation of SLECs are still not known. However, it has been shown that cytokines such as IL-2 induce Blimp-1 expression in vitro. In this study, we took advantage of the low-inflammation model of dendritic cell immunization to study the role of the IL-2/Blimp-1 axis in SLEC differentiation as well as the importance of Blimp-1 expression in memory precursor effector cells for proper CD8(+) memory generation. Our results show that Blimp-1 deficiency affects effector differentiation and function in the absence of inflammation. Unexpectedly, memory generation was not affected in Blimp-1-deficient OT-I cells responding to vaccination. In addition, modulation of the bioavailability of IL-2 by injection either of a blocking Ab or of the cytokine, demonstrates a link between IL-2, Blimp-1 induction, and SLEC formation in wild-type cells. Conversely, injection of IL-2 had less effect on Blimp-1-deficient CD8(+) T cells, indicating that the effect of IL-2 on in vivo SLEC differentiation is mediated by Blimp-1. In conclusion, IL-2 induction of Blimp-1 expression is a key regulator of SLEC differentiation in vivo. PMID:25015830

  16. 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.

  17. Voltammetric investigation of DNA damage induced by nitrofurazone and short-lived nitro-radicals with the use of an electrochemical DNA biosensor.

    PubMed

    Ni, Yongnian; Wang, Pingping; Kokot, Serge

    2012-01-01

    Electrochemical behavior of nitrofurazone (NFZ) was investigated with the use of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The pH-dependence of NFZ was studied at a glassy carbon electrode (GCE) in ethanol/Britton-Robinson buffer (30:70), and short-lived nitro-radicals were generated by the reduction of NFZ at high pHs (>7.0). In the presence of DNA, the DPV peak current of NFZ decreased and the peak potential shifted negatively, which indicated that there was an electrostatic interaction between NFZ and DNA. An electrochemical dsDNA/GCE biosensor was prepared to study the DNA damage produced in the presence NFZ; this process was followed with the use of the Co(phen)(3)(2+) electroactive probe. Also, the oxidation peaks of guanosine (750 mV) and adenosine (980 mV) indicated that DNA damage was related directly to the nitro-radicals. Experiments demonstrated that DNA damage occurred via two different steps while NFZ was metabolized and nitro-radicals were produced. Novel work with AFM on the NFZ/DNA interaction supported the suggestion that in vivo, the nitro-radicals were more cytotoxic than the NFZ molecules. A linear DPV calibration plot was obtained for NFZ analysis at a modified dsDNA/GCE (concentration range: 2.50 × 10(-6)-3.75 × 10(-5) mol L(-1); limit of detection: 8.0 × 10(-7) mol L(-1)), and NFZ was determined successfully in pharmaceutical samples. PMID:22717476

  18. 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.

  19. Collective degrees of freedom of neutron-rich A≈100 nuclei and the first mass measurement of the short-lived nuclide 100Rb

    NASA Astrophysics Data System (ADS)

    Manea, V.; Atanasov, D.; Beck, D.; Blaum, K.; Borgmann, C.; Cakirli, R. B.; Eronen, T.; George, S.; Herfurth, F.; Herlert, A.; Kowalska, M.; Kreim, S.; Litvinov, Yu. A.; Lunney, D.; Neidherr, D.; Rosenbusch, M.; Schweikhard, L.; Wienholtz, F.; Wolf, R. N.; Zuber, K.

    2013-11-01

    The mass surface in the A˜100 region of the nuclear chart is extended by the measurement of the 98-100Rb isotopes with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The mass of 100Rb is determined for the first time. The studied nuclides mark the known low-Z frontier of the shape transition at N=60. To describe the shape evolution towards the krypton isotopic chain, a theoretical analysis is presented in the framework of the Hartree-Fock-Bogoliubov approach. The importance of the pairing interaction for describing the extent and strength of the region of quadrupole deformation is emphasized. A later transition to large prolate deformation or, alternatively, the predominance of oblate deformation is proposed as explanation for the different behavior of the krypton isotopes. Octupole collectivity is explored as a possible mechanism for the evolution of two-neutron separation energies around N=56.

  20. Understanding the radiative impact of decadal trends in Short-Lived climate forcers over the Arctic troposphere: A significant role for non-BC species

    NASA Astrophysics Data System (ADS)

    Breider, T. J.; Mickley, L. J.; Jacob, D. J.; Fisher, J. A.; Wang, Q.; Koplitz, S. N.; Yantosca, R. M.

    2012-12-01

    Over recent decades the Arctic has experienced a period of rapid warming. Current general circulation models (GCMs) generally have difficulty reproducing the observed warming and sea ice loss. A possible explanation is the inadequate representation of Short Lived (SL) species (Aerosols and Ozone). In this work we have developed a model capable of providing a state-of-the-science estimate of multi-decadal trends in Arctic climate forcing from SL species. The model has been extensively tested against observations from the International Polar Year (IPY) in 2007-2008. We will present key findings from a simulation for 2008 using GEOS-Chem, followed by results from a 1980-2010 simulation assessing the impact of decadal trends in SL species. Our results indicate a large contribution from non-black carbon (BC) components to the spring-summer Arctic absorption aerosol optical depth (AAOD) and deposition of absorbing aerosol to the snowpack. We find organic carbon (OC) contributes 17% of spring-summer Arctic AAOD and 16% of the deposition to the snowpack. Dust is important during the spring (11% of Arctic AAOD and 25% of snowpack deposition). Source attribution shows the Sahara is a major source of Arctic dust indicating transport over Northern Europe is an important pathway of dust to the Arctic. Our results show the observed shift in the Arctic sulfate size distribution between spring and summer is key to reproducing the summertime aerosol optical depth (AOD) observations at Arctic AERONET stations. We also quantify the contribution of anthropogenic and open fires sources. For Arctic ozone, we find the anthropogenic influence is largest in the spring, increasing natural troposphere ozone by 46%. In the spring and summer, anthropogenic sources contribute 40% of Arctic AAOD, 26% of the absorbing mass deposited to the snowpack and 40% of the Arctic AOD. Our results emphasize the importance of open fires (agricultural and natural) as a source of SL species to the Arctic and a potential driver of change in the region. We will also quantify the radiative forcing from SL species in this work using the GISS model. Finally, we will show the first results from the 1980-2010 simulation assessing the contribution of SL species to Arctic climate forcing during this period.

  1. 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.

  2. Tracing historical tropical cyclones and the 1883 Krakatoa tsunami in short-lived geological archives of the Ashburton Delta (NW Australia)

    NASA Astrophysics Data System (ADS)

    May, Simon Matthias; Brill, Dominik; Engel, Max; Scheffers, Anja; Pint, Anna; Wennrich, Volker; Squire, Peter; Kelletat, Dieter; Brückner, Helmut

    2014-05-01

    Records of coastal geological archives are discontinuous. They store traces of both episodic and long-term processes as particular depositional landforms, deposits or erosional features. In particular the identification and interpretation of episodic high-energy coastal flooding due to tropical cyclones (TCs) and tsunamis is associated with a number of difficulties, including the spatial and temporal variability of geological records as well as the application of different dating techniques. In addition, the differentiation between tsunami and storm deposits remains challenging, notably where modern deposits and/or historical reports on the event are absent. Analysing modern (or historic) analogues for which documentation of process-specific parameters and/or geomorphic and sedimentary effects are available contributes to a better understanding of their sedimentary signatures and related depositional processes. These studies are key components to unravel the fossil record and the history of past events. The NW coast of Western Australia (WA) is highly vulnerable to extreme wave events. On average 1-2 TCs impact the W Australian coast per year, and ten historically documented tsunami events are recorded since 1858, including the tsunami following the 1883 Krakatoa eruption. However, no sedimentary evidence on this particular event has been presented yet, and little is known about the geological imprint of both (pre)historic TCs and tsunamis in NW Australia in general. Here we present new data on the sedimentology and chronostratigraphy of historical washover events found in short-lived geological archives of the Ashburton River delta (NW part of Western Australia), where clearly distinguishable traces of both TCs and the 1883 Krakatoa tsunami are recorded. We aim at (i) establishing (at least locally valid) sedimentary criteria differentiating between TCs and tsunami deposits; (ii) presenting an OSL-based local chronostratigraphy with direct relation to historical events; and (iii) discussing the archive's overall significance for palaeoevent research. Our results show that the presented archive is discontinuous on different spatial and temporal levels, related to the episodic nature of extreme wave events and the general variability of geological archives.

  3. The Prolyl Isomerase Pin1 Regulates mRNA Levels of Genes with Short Half-Lives by Targeting Specific RNA Binding Proteins

    PubMed Central

    Titus, Mark A.

    2014-01-01

    The peptidyl-prolyl isomerase Pin1 is over-expressed in several cancer tissues is a potential prognostic marker in prostate cancer, and Pin1 ablation can suppress tumorigenesis in breast and prostate cancers. Pin1 can co-operate with activated ErbB2 or Ras to enhance tumorigenesis. It does so by regulating the activity of proteins that are essential for gene expression and cell proliferation. Several targets of Pin1 such as c-Myc, the Androgen Receptor, Estrogen Receptor-alpha, Cyclin D1, Cyclin E, p53, RAF kinase and NCOA3 are deregulated in cancer. At the posttranscriptional level, emerging evidence indicates that Pin1 also regulates mRNA decay of histone mRNAs, GM-CSF, Pth, and TGFβ mRNAs by interacting with the histone mRNA specific protein SLBP, and the ARE-binding proteins AUF1 and KSRP, respectively. To understand how Pin1 may affect mRNA abundance on a genome-wide scale in mammalian cells, we used RNAi along with DNA microarrays to identify genes whose abundance is significantly altered in response to a Pin1 knockdown. Functional scoring of differentially expressed genes showed that Pin1 gene targets control cell adhesion, leukocyte migration, the phosphatidylinositol signaling system and DNA replication. Several mRNAs whose abundance was significantly altered by Pin1 knockdown contained AU-rich element (ARE) sequences in their 3′ untranslated regions. We identified HuR and AUF1 as Pin1 interacting ARE-binding proteins in vivo. Pin1 was also found to stabilize all core histone mRNAs in this study, thereby validating our results from a previously published study. Statistical analysis suggests that Pin1 may target the decay of essential mRNAs that are inherently unstable and have short to medium half-lives. Thus, this study shows that an important biological role of Pin1 is to regulate mRNA abundance and stability by interacting with specific RNA-binding proteins that may play a role in cancer progression. PMID:24416409

  4. Be-B Isotope Systematics in CV and CM Hibonites: Implications for Solar Energetic Particle Production of Short-lived Nuclides in Early Solar System

    NASA Astrophysics Data System (ADS)

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

    2003-03-01

    Presence of radiogenic 10B in HAL hibonite with extremely low initial 26Al/27Al ratio of ~5x10**-8 and in CM hibonites devoid of radiogenic 26Mg conclusively establish that the source of 10Be present in early solar system didnot contribute significant amount of 26Al, 41Ca and 53Mn.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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 enamel represent underdetermined systems, our results demonstrate that they can provide useful information about dietary variability if the mineralization process is taken into account.

  10. Short communication: milk output in llamas (Lama glama) in relation to energy intake and water turnover measured by an isotope dilution technique.

    PubMed

    Riek, A; Klinkert, A; Gerken, M; Hummel, J; Moors, E; Sdekum, K-H

    2013-03-01

    Despite the fact that llamas have become increasingly popular as companion and farm animals in both Europe and North America, scientific knowledge on their nutrient requirements is scarce. Compared with other livestock species, relatively little is known especially about the nutrient and energy requirements for lactating llamas. Therefore, we aimed to measure milk output in llama dams using an isotope dilution technique and relate it to energy intakes at different stages of lactation. We also validated the dilution technique by measuring total water turnover (TWT) directly and comparing it with values estimated by the isotope dilution technique. Our study involved 5 lactating llama dams and their suckling young. Milk output and TWT were measured at 4 stages of lactation (wk 3, 10, 18, and 26 postpartum). The method involved the application of the stable hydrogen isotope deuterium ((2)H) to the lactating dam. Drinking water intake and TWT decreased significantly with lactation stage, whether estimated by the isotope dilution technique or calculated from drinking water and water ingested from feeds. In contrast, lactation stage had no effect on dry matter intake, metabolizable energy (ME) intake, or the milk water fraction (i.e., the ratio between milk water excreted and TWT). The ratios between TWT measured and TWT estimated (by isotope dilution) did not differ with lactation stage and were close to 100% in all measurement weeks, indicating that the D(2)O dilution technique estimated TWT with high accuracy and only small variations. Calculating the required ME intakes for lactation from milk output data and gross energy content of milk revealed that, with increasing lactation stage, ME requirements per day for lactation decreased but remained constant per kilogram of milk output. Total measured ME intakes at different stages of lactation were similar to calculated ME intakes from published recommendation models for llamas. PMID:23332845

  11. The Effectiveness of Healthy Physical Fitness Programs on People with Intellectual Disabilities Living in a Disability Institution: Six-Month Short-Term Effect

    ERIC Educational Resources Information Center

    Wu, Chia-Ling; Lin, Jin-Ding; Hu, Jung; Yen, Chia-Feng; Yen, Cheng-Tung; Chou, Yu-Lan; Wu, Po-Hsun

    2010-01-01

    Little information is available on the provision of physical fitness and intervention program among people with intellectual disabilities. The aim of this study is to provide information of examining the effectiveness of healthy physical fitness programs on people with intellectual disabilities living in a disability institution. There were 146

  12. The Effectiveness of Healthy Physical Fitness Programs on People with Intellectual Disabilities Living in a Disability Institution: Six-Month Short-Term Effect

    ERIC Educational Resources Information Center

    Wu, Chia-Ling; Lin, Jin-Ding; Hu, Jung; Yen, Chia-Feng; Yen, Cheng-Tung; Chou, Yu-Lan; Wu, Po-Hsun

    2010-01-01

    Little information is available on the provision of physical fitness and intervention program among people with intellectual disabilities. The aim of this study is to provide information of examining the effectiveness of healthy physical fitness programs on people with intellectual disabilities living in a disability institution. There were 146…

  13. The DOE Isotopes Program

    NASA Astrophysics Data System (ADS)

    Gillo, Jehannes

    2015-10-01

    The DOE Isotope Program is a small federal program with a great deal of impact and is managed by the DOE Office of Nuclear Physics. The Isotope Program has been managed by the Office of Nuclear Physics since 2009, and since that time, has been re-defined in terms of mission, scope and operations. The program produces critical isotopes that are in short supply or simply unavailable from elsewhere to facilitate research and applications. Research is also supported to develop or improve production techniques that will increase availability of isotopes in high demand, such as alpha emitters for cancer therapy.

  14. 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 magmas developed in an aphyric condition, and their porphyritic character is an artifact of eruption; and (2) that a protective, mechanically rigid cognate carapace around a silicic magma chamber may limit interaction with low-δ 18O hydrothermally altered crust, thus hindering the development of significant volumes of low-δ 18O silicic magma.

  15. Age and isotopic relationships among the angrites Lewis Cliff 86010 and Angra dos Reis

    NASA Technical Reports Server (NTRS)

    Lugmair, G. W.; Galer, S. J. G.

    1992-01-01

    The paper presents results of a wide-ranging isotopic investigation of the the Antarctic angrite LEW-86010 (LEW), and reassesses the type angrite Angra dos Reis (ADOR) in order to obtain precise radiometric ages and initial Sr isotopic compositions, and to search for the erstwhile presence of the short-lived nuclei Sm-146 and Al-26 via their daughter products. The isotopic compositions of Sm, U, Ca, and Ti were measured to allow a detailed appraisal to be made of the relations between, and the geneology of, these two angrites. LEW proves to be severely contaminated with modern terrestrial Pb, which is shown to result from terrestrial weathering. Concordant Pb-Pb model ages of pyroxene separates are obtained; uranium isotopic compositions are normal within error. Overall, striking age and isotopic similarities between LEW and ADOR were found, suggesting almost simultaneous production on the same asteroid, even though recent experimental studies imply that the two are not comagmatic.

  16. Isotope abundance of {sup 180}Ta{sup m} and p-process nucleosynthesis

    SciTech Connect

    Laeter, J.R. de; Bukilic, N.

    2005-08-01

    The p-process of stellar nucleosynthesis produces the stable neutron-deficient nuclides heavier than the iron peak elements. An accurate determination of the isotopic composition of tantalum is required to enable p-process nucleosynthetic calculations to be evaluated in terms of an accurate isotope abundance for {sup 180}Ta. This odd-odd nuclide has the remarkable property of having a long-lived isomeric state and a short-lived ground state, so that in reality one is measuring the isotope abundance of {sup 180}Ta{sup m}, which is a unique situation in nature. {sup 180}Ta{sup m} is the rarest isotope of nature's rarest element and is therefore an important isotope in deciphering the origin of the p-process. Because the isotopic composition of tantalum has only been measured on two occasions with relatively large uncertainties, an accurate determination is required to provide a better basis for p-process production calculations. A thermal ionization mass spectrometer was used to measure the isotope abundance of {sup 180}Ta{sup m} with high precision. The linearity of this instrument was verified by measuring the isotopically certified reference material for potassium (NIST 985), whose isotopes span a wide range of isotope ratios. The abundance sensitivity of the mass spectrometer for the measured ion beams has been examined to ensure the absence of tailing effects and interfering isotopes. These procedures are essential because of the extremely low isotope abundance of {sup 180}Ta{sup m}. The isotope fractionation of the tantalum isotopes was estimated by reference to the isotope fractionation of the isotopically certified reference material for rhenium (NIST 989). The isotopic composition of tantalum has been determined to be {sup 181}Ta/{sup 180}Ta{sup m}=8325 {+-} 43, which gives isotope abundances for {sup 180}Ta{sup m}=0.0001201 {+-} 0.0000008 and {sup 181}Ta=0.9998799 {+-} 0.0000008. This gives a Solar System abundance of {sup 180}Ta{sup m} of 2.49 x 10{sup -6} with reference to silicon=10{sup 6}. These isotope abundances, together with the relative atomic masses, give an atomic weight for tantalum of 180.947878 {+-} 0.000002.

  17. Chemical and Isotopic Study of Lab-formed Carbonates Under Cryogenic and Hydrothermal Conditions

    NASA Technical Reports Server (NTRS)

    Niles, P. B.; Leshin, L. A.; Socki, R. A.; Guan, Y.; Golden, D. C.; Ming, D. W.; Gibson, E. K.

    2004-01-01

    Aqueous environments on early Mars were probably relatively short-lived and localized, as evidenced by the lack of abundant secondary minerals detected by the TES instrument. In order to better understand the aqueous history of early Mars we need to be able to interpret the evidence preserved in secondary minerals formed during these aqueous events. Carbonate minerals, in particular, are important secondary minerals for interpreting past aqueous environments as illustrated by the carbonates preserved in ALH84001. Carbonates formed in short-lived, dynamic aqueous events often preserve kinetic rather than equilibrium chemical and isotopic processes, and predicting the behavior of such systems is facilitated by empirical data.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. [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

  3. Arctic warming: Short-term solutions

    NASA Astrophysics Data System (ADS)

    Schmale, Julia

    2016-03-01

    Arctic temperatures are increasing because of long- and short-lived climate forcers, with reduction of the short-lived species potentially offering some quick mitigation. Now a regional assessment reveals the emission locations of these short-lived species and indicates international co-operation is needed to develop an effective mitigation plan.

  4. Listeria monocytogenes as a short-lived delivery system for the induction of type 1 cell-mediated immunity against the p36/LACK antigen of Leishmania major.

    PubMed

    Soussi, N; Milon, G; Colle, J H; Mougneau, E; Glaichenhaus, N; Goossens, P L

    2000-03-01

    Listeria monocytogenes has been used as an experimental live vector for the induction of CD8-mediated immune responses in various viral and tumoral experimental models. Susceptibility of BALB/c mice to Leishmania major infection has been correlated to the preferential development of Th2 CD4 T cells through an early production of interleukin 4 (IL-4) by a restricted population of CD4 T cells which react to a single parasite antigen, LACK (stands for Leishmania homologue of receptors for activated C kinase). Experimental vaccination with LACK can redirect the differentiation of CD4(+) T cells towards the Th1 pathway if LACK is coadministrated with IL-12. As IL-12 is known to be induced by L. monocytogenes, we have tested the ability of a recombinant attenuated actA mutant L. monocytogenes strain expressing LACK to induce the development of LACK-specific Th1 cells in both B10.D2 and BALB/c mice, which are resistant and susceptible to L. major, respectively. After a single injection of LACK-expressing L. monocytogenes, IL-12/p40 transcripts showed a rapid burst, and peaks of gamma interferon (IFN-gamma)-secreting LACK-specific Th1 cells were detected around day 5 in the spleens and livers of mice of both strains. These primed IFN-gamma-secreting LACK-reactive T cells were not detected ex vivo after day 7 of immunization but could be recruited and detected 15 days later in the draining lymph node after an L. major footpad challenge. Although immunization of BALB/c mice with LACK-expressing L. monocytogenes did not change the course of the infection with L. major, immunized B10.D2 mice exhibited significantly smaller lesions than nonimmunized controls. Thus, our results demonstrate that, in addition of its recognized use for the induction of effector CD8 T cells, L. monocytogenes can also be used as a live recombinant vector to favor the development of potentially protective IFN-gamma-secreting Th1 CD4 T lymphocytes. PMID:10678966

  5. 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. PMID:22214532

  6. 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.

  7. 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

  8. Rapid increase in cosmogenic 14C in AD 775 measured in New Zealand kauri trees indicates short-lived increase in 14C production spanning both hemispheres

    NASA Astrophysics Data System (ADS)

    Güttler, D.; Adolphi, F.; Beer, J.; Bleicher, N.; Boswijk, G.; Christl, M.; Hogg, A.; Palmer, J.; Vockenhuber, C.; Wacker, L.; Wunder, J.

    2015-02-01

    In 2012, Miyake et al. reported a sudden and strong increase of the atmospheric radiocarbon (14C) content in Japanese cedar trees of 1.2% between AD 774 and 775. While their findings were quickly confirmed by a German oak chronology for the Northern Hemisphere (NH), the question remained if the effect was seen in both hemispheres. Here we present the first annually resolved Southern Hemisphere (SH) 14C record spanning the interval AD 760-787, using New Zealand kauri (Agathis australis) chronology wood. An almost identical distinct increase compared to Northern Hemisphere data was observed, suggesting a cosmic event with globally uniform impact as a potential cause for the increase. Deploying a carbon cycle box model a worldwide averaged net 14C production of 2.2 ×108 14C atoms cm-2 was estimated, which is 3.7 times higher than the average annual 14C production. The immediate appearance of the event in tree rings on both hemispheres suggests a short duration event of significantly less than 1 yr.

  9. Quantum yield measurements of short-lived photoactivation intermediates in DNA photolyase: toward a detailed understanding of the triple tryptophan electron transfer chain.

    PubMed

    Byrdin, Martin; Lukacs, Andras; Thiagarajan, Viruthachalam; Eker, André P M; Brettel, Klaus; Vos, Marten H

    2010-03-11

    The light-dependent DNA repair enzyme photolyase contains a unique evolutionary conserved triple tryptophan electron transfer chain (W382-W359-W306 in photolyase from E. coli) that bridges the approximately 15 A distance between the buried flavin adenine dinucleotide (FAD) cofactor and the surface of the protein. Upon excitation of the semireduced flavin (FADH(o)), electron transfer through the chain leads to formation of fully reduced flavin (FADH(-); required for DNA repair) and oxidation of the most remote tryptophan residue W306, followed by its deprotonation. The thus-formed tryptophanyl radical W306(o)(+) is reduced either by an extrinsic reductant or by reverse electron transfer from FADH(-). Altogether the kinetics of these charge transfer reactions span 10 orders of magnitude, from a few picoseconds to tens of milliseconds. We investigated electron transfer processes in the picosecond-nanosecond time window bridging the time domains covered by ultrafast pump-probe and "classical" continuous probe techniques. Using a recent dedicated setup, we directly show that virtually no absorption change between 300 ps and 10 ns occurs in wild-type photolyase, implying that no charge recombination takes place in this time window. In contrast, W306F mutant photolyase showed a partial absorption recovery with a time constant of 0.85 ns. In wild-type photolyase, the quantum yield of FADH(-) W306(o)(+) was found at 19 +/- 4%, in reference to the established quantum yield of the long-lived excited state of [Ru(bpy)(3)](2+). With this yield, the optical spectrum of the excited state of FADH(o) can be constructed from ultrafast spectroscopic data; this spectrum is dominated by excited state absorption extending from below 450 to 850 nm. The new experimental results, taken together with previous data, allow us to propose a detailed kinetic and energetic scheme of the electron transfer chain. PMID:19954157

  10. {sup 90}Y-{sup 90}Sr disequilibrium in surface waters : investigating short-term particle dynamics by using a novel isotope pair.

    SciTech Connect

    Orlandini, K. A.; Bowling, J. W.; Pinder, J. E.; Penrose, W. R.; Environmental Research; Procter and Gamble; Colorado State Univ.; Illinois Inst. of Tech.

    2003-01-01

    We demonstrate the use of the disequilibrium between {sup 90}Sr (t{sub 1/2}=29.1 yr) and its particle-reactive daughter {sup 90}Y (t{sub 1/2}=64 h) to estimate particle removal rates and settling velocities in the epilimnion of a freshwater lake during varying conditions of stratification caused by seasonal changes. The estimated rates of removal obtained from the {sup 90}Sr-{sup 90}Y disequilibrium showed good agreement with (a) measured rates of mass removal obtained from settling particle fluxes in sediment traps and the inventories of suspended material and (b) independently obtained removal coefficients for the scavenging behavior of two different isotopes of particle-reactive plutonium, present in the water column because of different processes. Because 90Sr is widespread and readily measurable in freshwater systems as a result of fallout from nuclear weapons testing, the {sup 90}Sr-{sup 90}Y disequilibrium is a potentially valuable resource for examining particle dynamics in surface waters.

  11. Hydrogen and 40Ar/39Ar isotope evidence for multiple and protracted paleofluid flow events within the long-lived North Anatolian Keirogen (Turkey)

    NASA Astrophysics Data System (ADS)

    Boles, Austin; van der Pluijm, Ben; Mulch, Andreas; Mutlu, Halim; Uysal, I. Tonguç; Warr, Laurence N.

    2015-06-01

    We present a new approach to identifying the source and age of paleofluids associated with low-temperature deformation in the brittle crust, using hydrogen isotopic compositions (δD) and 40Ar/39Ar geochronology of authigenic illite in clay gouge-bearing fault zones. The procedure involves grain-size separation, polytype modeling, and isotopic analysis, creating a mixing line that is used to extrapolate to δD and age of pure authigenic and detrital material. We use this method on samples collected along the surface trace of today's North Anatolian Fault (NAF). δD values of the authigenic illite population, obtained by extrapolation, are -89 ± 3‰, -90 ± 2‰, and -97 ± 2‰ (VSMOW) for samples KSL, RES4-1, and G1G2, respectively. These correspond to δD fluid values of -62‰ to -85‰ for the temperature range of 125°C ± 25°, indistinguishable from present-day precipitation values. δD values of the detrital illite population are -45 ± 13‰, -60 ± 6‰, and -64 ± 6‰ for samples KSL, G1G2, and RES4-1, respectively. Corresponding δD fluid values at 300°C are -26‰ to -45‰ and match values from adjacent metamorphic terranes. Corresponding clay gouge ages are 41.4 ± 3.4 Ma (authigenic) and 95.8 ± 7.7 Ma (detrital) for sample G2 and 24.6 ± 1.6 Ma (authigenic) and 96.5 ± 3.8 Ma (detrital) for sample RES4-1, demonstrating a long history of meteoric fluid infiltration in the area. We conclude that today's NAF incorporated preexisting, weak clay-rich rocks that represent earlier mineralizing fluid events. The samples preserve at least three fluid flow pulses since the Eocene and indicate that meteoric fluid has been circulating in the upper crust in the North Anatolian Keirogen since that time.

  12. 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

    IL-15 has pivotal roles in the control of CD8{sup +} memory T cells and has been investigated as a therapeutic option in cancer therapy. Although IL-15 and IL-2 share many functions together, including the stimulation of CD8 T cell proliferation and IFN-γ production, the different in vivo roles of IL-15 and IL-2 have been increasingly recognized. Here, we explored the different effects of IL-15 and IL-2 on tumor-infiltrating (TI) T cells from resected breast tumors. We found that neither IL-2 nor IL-15 induced intratumoral CD8 T cell proliferation by itself, but after CD3/CD28-stimulation, IL-15 induced significantly higher proliferation than IL-2 during early time points, at day 2, day 3 and day 6. However, the IL-15-induced proliferation leveled off at day 9 and day 12, whereas IL-2 induced lower but progressive proliferation at each time point. Furthermore, IL-15 caused an early and robust increase of IFN-γ in the supernatant of TI cell cultures, which diminished at later time points, while the IL-2-induced IFN-γ production remained constant over time. In addition, the IL-15-costimulated CD8 T cells presented higher frequencies of apoptotic cells. The diminishing IL-15-induced response was possibly due to regulatory and/or exhaustion mechanisms. We did not observe increased IL-10 or PD-1 upregulation, but we have found an increase of Tim-3 upregulation on IL-15-, but not IL-2-stimulated cells. Blocking Tim-3 function using anti-Tim-3 antibodies resulted in increased IL-15-induced proliferation and IFN-γ production for a prolonged period of time, whereas adding Tim-3 ligand galectin 9 led to reduced proliferation and IFN-γ production. Our results suggest that IL-15 in combination of Tim-3 blocking antibodies could potentially act as an IL-2 alternative in tumor CD8 T cell expansion in vitro, a crucial step in adoptive T cell therapy. - Highlights: • We explored the effects of IL-15 and IL-2 on tumor-infiltrating (TI) T cells of breast cancer. • IL-15 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.

  13. Short Magma Residence Times at Mt. Rainier and the Probable Absence of a Large, Integrated, and Long-lived Magma Reservoir System

    NASA Astrophysics Data System (ADS)

    Sisson, T. W.; Lanphere, M. A.

    2003-12-01

    Intensive, high-precision K-Ar and 40Ar/39Ar geochronology have proven essential for producing modern geologic maps of volcanoes and from these determining the volcanoes' time-volume histories. If sufficiently abundant, these data can also reveal aspects of the magma supply system. For Cascade volcanoes a general result has been the demonstration that edifice growth is highly episodic. Mount Rainier grew in the last 500,000 years atop the remains of an ancestral edifice that was active in the same location 1 - 2 Myr ago. The 500,000 year history of the modern edifice falls into four stages of alternating high and low magmatic output of subequal duration, but major and trace element compositions of eruptives show no correlation with volcano growth stages. Instead, the same spectrum of magmas (andesite to low-Si dacite) erupted throughout the history of the volcano with compositions in the same relative abundances. Superimposed on this seemingly null result are at least 6 brief but pronounced excursions in magma trace-element compositions. Concentrations of Zr, Ba, or Sr can double and then return to background values passing into and out of a single flow or flow-group. Some excursions are tightly bracketed by mapping and by measured ages and have durations no more than the geochronologic measurement precision of about 10,000 years. True excursion durations are potentially much shorter. The brevity and abrupt onsets and cessations of these compositional excursions are evidence against the presence of a sizeable, long-lived magma reservoir anywhere beneath the volcano, including a MASH zone in the lower crust, that would have attenuated, dampened, and homogenized compositional excursions introduced into the magmatic system. Instead, we take 10,000 years as a probable upper limit to the average residence time of magma batches transiting the crustal portion of Mount Rainier's plumbing system. A consistent scenario is that parental magmas enter the crust, differentiate, assimilate, and either erupt or solidify in less than 10,000 years. Geochronologic evidence from much larger magmatic systems (Reid and coworkers, Long Valley, Yellowstone) suggests that more productive systems can have much longer average residence times than modestly active arc stratovolcanoes like Mt. Rainier.

  14. 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

  15. 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 sources for Co, Mg, Fe, Ca, Cr, Ni, Sn, Li and Sb and Na, V, Cl, Mn, Al, Br and K. The PCA/FA identified 3 dominant factors as responsible for the data structure, explaining 84.5% of the total variance in the dataset.

  16. 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

    HFC-134a (1,1,1,2-tetrafluoroethane) is the prevalent (used in >80% passenger cars and commercial vehicles worldwide) refrigerant in automobile air conditioning units (MACs). With an atmospheric lifetime of ~14 years and a global warming potential (GWP) of 1430 on a 100-year time horizon, HFC-134a does not meet current and expected requirements for MAC refrigerants in many parts of the world. Therefore, substitutes with lower GWP are being sought. One of the simplest way to achieve lower GWP is to use chemicals with shorter atmospheric lifetimes. In this work, we investigate the dry and wet deposition and the rainwater concentration of trifluoroacetic acid (TFA) produced by the atmospheric oxidation of 2,3,3,3-tetrafluoropropene (TFP) and 1,2,3,3,3-pentafluoropropene (PFP). The WRF/Chem model was used to calculate dry and wet TFA deposition over the contiguous USA during the May-September 2006 period that would result from replacing HFC-134a in MACs with a 1:1 molar ratio mixture of 2,3,3,3-tetrafluoropropene (TFP) and 1,2,3,3,3-pentafluoropropene (PFP). The simulation is evaluated by comparing observations of precipitation and sulfate wet deposition at stations of the National Atmospheric Deposition Program (NADP). Simulated precipitation and sulfate wet deposition correlate well with the observations, but exhibit a positive bias for precipitation and a negative bias for sulfate wet deposition. Atmospheric lifetimes of TFP and PFP against oxidation by the hydroxyl radical OH, a prognostic species in WRF/Chem, are ~5 and ~4 days in the simulation, respectively. The model setup allows the attribution of dry and wet TFA deposition to individual source regions (California, Houston, Chicago, and the remaining contiguous USA in this work). TFA deposition is highest in the eastern USA because of numerous large sources and high precipitation in the region. West of the Continental Divide, TFA deposition is significantly lower, and its origin is dominated by emissions from 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.

  17. Groundtruthing the CSIA-aerosol technique for estimation of carbon isotopic discrimination of terrestrial photosynthesis

    NASA Astrophysics Data System (ADS)

    Conte, M. H.; Weber, J. C.; Flanagan, L. P.

    2001-05-01

    The carbon isotopic composition of vascular plant-derived leaf wax compounds present in aerosols can potentially provide a highly temporally resolved estimate of terrestrial photosynthetic fractionation of carbon dioxide on ecosystem and larger spatial scales. A central assumption of this approach is that the isotopic signal of the leaf waxes ablated off living vegetation by wind and dust scouring and accumulating in the atmosphere can be linked quantitatively to carbon isotopic fractionation by plant photosynthesis. To test this assumption we conducted a "groundtruthing" study in an Alberta short-grass prairie to assess the constancy of isotopic fractionation between leaf wax compounds and bulk carbon in major C3 and C4 plant species and also the linkage between waxes in bulked biomass and in aerosols collected at the site. We found that the isotopic fractionation factor for leaf waxes in these prairie plants does not vary significantly either among species or during the growing season, and also that the isotopic signal of ablated waxes in the aerosols is consistent with that in the local vegetation. Our results provide additional support for the validity of this novel biomarker-aerosol based approach and also new data needed to constrain the isotopic fractionation factor used to convert the plant wax signal in aerosols to an estimate of carbon isotopic discrimination of terrestrial photosynthesis.

  18. Abstracts of the 24th international isotope society (UK group) symposium: synthesis and applications of labelled compounds 2015.

    PubMed

    Aigbirhio, F I; Allwein, S; Anwar, A; Atzrodt, J; Audisio, D; Badman, G; Bakale, R; Berthon, F; Bragg, R; Brindle, K M; Bushby, N; Campos, S; Cant, A A; Chan, M Y T; Colbon, P; Cornelissen, B; Czarny, B; Derdau, V; Dive, V; Dunscombe, M; Eggleston, I; Ellis-Sawyer, K; Elmore, C S; Engstrom, P; Ericsson, C; Fairlamb, I J S; Georgin, D; Godfrey, S P; He, L; Hickey, M J; Huscroft, I T; Kerr, W J; Lashford, A; Lenz, E; Lewinton, S; L'Hermite, M M; Lindelöf, Å; Little, G; Lockley, W J S; Loreau, O; Maddocks, S; Marguerit, M; Mirabello, V; Mudd, R J; Nilsson, G N; Owens, P K; Pascu, S I; Patriarche, G; Pimlott, S L; Pinault, M; Plastow, G; Racys, D T; Reif, J; Rossi, J; Ruan, J; Sarpaki, S; Sephton, S M; Simonsson, R; Speed, D J; Sumal, K; Sutherland, A; Taran, F; Thuleau, A; Wang, Y; Waring, M; Watters, W H; Wu, J; Xiao, J

    2016-04-01

    The 24th annual symposium of the International Isotope Society's United Kingdom Group took place at the Møller Centre, Churchill College, Cambridge, UK on Friday 6th November 2015. The meeting was attended by 77 delegates from academia and industry, the life sciences, chemical, radiochemical and scientific instrument suppliers. Delegates were welcomed by Dr Ken Lawrie (GlaxoSmithKline, UK, chair of the IIS UK group). The subsequent scientific programme consisted of oral presentations, short 'flash' presentations in association with particular posters and poster presentations. The scientific areas covered included isotopic synthesis, regulatory issues, applications of labelled compounds in imaging, isotopic separation and novel chemistry with potential implications for isotopic synthesis. Both short-lived and long-lived isotopes were represented, as were stable isotopes. The symposium was divided into a morning session chaired by Dr Rebekka Hueting (University of Oxford, UK) and afternoon sessions chaired by Dr Sofia Pascu (University of Bath, UK) and by Dr Alan Dowling (Syngenta, UK). The UK meeting concluded with remarks from Dr Ken Lawrie (GlaxoSmithKline, UK). PMID:26991121

  19. 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.

  20. 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.

  1. Radium isotope quartet in groundwater as a proxy for identification of aquifer rocks and mechanisms of water-rock interactions: examples from the Negev, Israel

    NASA Astrophysics Data System (ADS)

    Vengosh, A.; Pery, N.; Paytan, A.; Haquin, G.; Elhanani, S.; Pankratov, I.

    2006-05-01

    Many aquifer systems are composed of multiple rock types. Previous attempts to evaluate the specific aquifer rocks that control the groundwater chemistry and possible flow paths within these multiple lithological systems have used major ion chemistry and isotopic tracers (e.g., strontium isotopes). Here we propose an additional isotopic proxy that is based on the distribution of radium isotopes in groundwater. Radium has four radioactive isotopes that are part of the decay chains of uranium-238, thorium-232, and uranium-235. The abundance of radium isotope quartet (226Ra-half life 1600 y; 228Ra-5.6 y; 224Ra-3.6 d; 223Ra-11.4 d) in groundwater reflects the Th/U ratios in the rocks. Investigation of groundwater from the Negev, Israel, enabled us to discriminate between groundwaters flowing in the Lower Cretaceous Nubian Sandstone and the Upper Cretaceous Judea Group carbonate aquifers. Groundwater flowing in the sandstone aquifer has distinguishably high 228Ra/226Ra and 224Ra/223Ra ratios due to the high Th/U ratio in sandstone. In contrast, the predominance of uranium in carbonate rocks results in low 228Ra/226Ra and 224Ra/223Ra ratios in the associated groundwater. We show that the radium activity in groundwater in the two-aquifer systems is correlated with temperature, dissolved oxygen, and salinity. The increase of radium activity is also associated with changes in the isotopic ratios; 228Ra/226Ra ratios increase and decrease in the sandstone and carbonate aquifers, respectively. Given that the dissolution of radium isotopes depends on their decay constants, the use of the four radium isotopes with different decay constants enabled us to distinguish between dissolution (higher abundance of the long-lived isotopes) and recoil (predominance of the short-lived isotopes) processes. In spite of these isotopic fractionations, the radium isotopic discrimination between carbonate and sandstone aquifers is significant.

  2. 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.

  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 for homogeneous doping of floating zone Si with P, holds perhaps the biggest promises for isotopically controlled semiconductors and is discussed in some detail. Local vibrational modes of low-mass impurities are sensitive to the mass of the impurity as well as the masses of the host atoms neighboring the impurity. High-resolution infrared-absorption studies of O in Ge crystals of different isotopic composition demonstrate the extreme simplification in such spectra which is achieved by isotope control. Interdiffusion of GaAs and Ge isotope superlattices with 0.1-1 μm thick layers have been studied with secondary-ion-mass spectroscopy. This kind of internal diffusion avoids the problems with surface effects and can produce accurate data without the need for radioactive tracers. The review closes with an outlook on the exciting future possibilities offered through isotope control of a wide range of semiconductor materials.

  4. Pb isotopic tracers of the Cretaceous-Tertiary extinction event

    SciTech Connect

    Galer, S.J.G.; Macdougall, J.D.; Erickson, D.J. III )

    1989-11-01

    The global excess of Ir in sediments at the Cretaceous-Tertiary (K-T) boundary has been attributed to either a meteorite impact or enhanced volcanism (e.g. Decan Traps). The isotropic composition of Pb associated with this Ir provides a test of these hypotheses because meteoritic Pb is isotopically quite distinct from Pb of volcanic or continental origin. Pb abundances and isotopic compositions of pelagic oozes from DSDP Site 577A (Shatsky Rise, NW Pacific) measured in this study show little change over the deposition interval of Ir-rich sediment ({approximately}10 cm). However, a Pb enriched layer with a more radiogenic isotopic composition is found in the basal {approximately}0.5 cm of the Tertiary. These observations appear to preclude the Ir excess in these sediments originating as impact fallout from a stony meteorite although an iron meteorite impactor cannot be excluded. Any Pb flux accompanying Ir in volcanogenic aerosols from the Decan Traps should be considerable. However, the boundary Pb spike does not isotopically resemble known Deccan Trap lavas. There is isotopic overlap with coal ash although the lack of correlation between soot and Pb abundance precludes any simple relationship between the two. Overall, any wind pattern changes following the K-T event were apparently short-lived as neither airborne sources of Pb nor their magnitude to the then central Pacific were affected while Ir enriched sediments were being laid down.

  5. The effect of copper on the precipitation of scorodite (FeAsO4·2H2O) under hydrothermal conditions: evidence for a hydrated copper containing ferric arsenate sulfate-short lived intermediate.

    PubMed

    Gomez, M A; Becze, L; Celikin, M; Demopoulos, G P

    2011-08-15

    The effect of copper sulfate on scorodite precipitation and its mechanism of formation at 150 °C was investigated. Scorodite was determined to be the dominant phase formed under all conditions explored (0.61 < Fe(III)/As(V) < 1.87, 0.27-0.30 M Fe(SO(4))(1.5), 0-0.3 M CuSO(4), 0-0.3 M MgSO(4), at 2.5 h and 150 °C). The produced scorodite was found to incorporate up to 5% SO(4) and ≤1% Cu or Mg in its structure. The precipitation of scorodite was stoichiometric, i.e. the Fe/As molar ratio in the solids was equal to one independent of the starting Fe/As ratio in the solution. The presence of excess ferric sulfate in the initial solution (Fe/As>1) was found to slow down the ordering of the H-bond structure in scorodite. Precipitation under equimolar concentrations (As = Fe = Cu = 0.3 M), short times and lower temperatures (30-70 min and 90-130 °C) revealed the formation of a Cu-Fe-AsO(4)-SO(4)-H(2)O short lived gelatinous intermediate that closely resembled the basic ferric arsenate sulfate (BFAS) type of phase, before ultimately converting fully to the most stable scorodite phase (96 min and 138 °C). This phase transition has been traced throughout the reaction via elemental (ICP-AES, XPS), structural (PXRD, TEM) and molecular (ATR-IR, Raman) analysis. ATR-IR investigation of an arsenic containing industrial residue produced during pressure leaching of a copper concentrate (1 h and 150 °C) found evidence of the formation of an arsenate mineral form resembling the intermediate basic ferric arsenate sulfate phase. PMID:21621789

  6. 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.

  7. 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.

  8. 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.

  9. Estimating the timing of diet shifts using stable isotopes.

    PubMed

    Phillips, Donald L; Eldridge, Peter M

    2006-03-01

    Stable isotope analysis has become an important tool in studies of trophic food webs and animal feeding patterns. When animals undergo rapid dietary shifts due to migration, metamorphosis, or other reasons, the isotopic composition of their tissues begins changing to reflect that of their diet. This can occur both as a result of growth and metabolic turnover of existing tissue. Tissues vary in their rate of isotopic change, with high turnover tissues such as liver changing rapidly, while relatively low turnover tissues such as bone change more slowly. A model is outlined that uses the varying isotopic changes in multiple tissues as a chemical clock to estimate the time elapsed since a diet shift, and the magnitude of the isotopic shift in the tissues at the new equilibrium. This model was tested using published results from controlled feeding experiments on a bird and a mammal. For the model to be effective, the tissues utilized must be sufficiently different in their turnover rates. The model did a reasonable job of estimating elapsed time and equilibrial isotopic changes, except when the time since the diet shift was less than a small fraction of the half-life of the slowest turnover tissue or greater than 5-10 half-lives of the slowest turnover tissue. Sensitivity analyses independently corroborated that model estimates became unstable at extremely short and long sample times due to the effect of random measurement error. Subject to some limitations, the model may be useful for studying the movement and behavior of animals changing isotopic environments, such as anadromous fish, migratory birds, animals undergoing metamorphosis, or animals changing diets because of shifts in food abundance or competitive interactions. PMID:16341714

  10. Isotopic heterogeneities in the solar system - Special report

    NASA Technical Reports Server (NTRS)

    Wasserburg, G. J.; Papanastassiou, D. A.; Lee, T.

    1979-01-01

    The paper discusses the nature of isotopic anomalies in solar system material with emphasis on correlated anomalies in refractory elements. Evidence for the existence of short-lived radioactive nuclides in the early solar system is used to estimate the time scale for the last injection of freshly synthesized nuclear material. It is shown that the early solar nebula was incompletely mixed and contained debris which was injected from a stellar source at most a few million years prior to the formation of the solar system. The average solar system material consists of ambient interstellar material deficient in certain nuclear species to which a small fraction of freshly synthesized material was added. The isotopic variations reflect slightly different proportions of nuclei from different stellar sources which were locally well mixed and homogenized prior to or during the formation of the early solar nebula condensates.

  11. Production of Cs and Fr isotopes from a high-density UC targets with different grain dimensions

    NASA Astrophysics Data System (ADS)

    Panteleev, V. N.; Alyakrinskiy, O.; Barbui, M.; Barzakh, A. E.; Fedorov, D. V.; Ivanov, V. S.; Lhersonneau, G.; Mezilev, K. A.; Molkanov, P. L.; Moroz, F. V.; Orlov, S. Yu.; Stroe, L.; Tecchio, L. B.; Tonezzer, M.; Volkov, Yu. M.

    2009-12-01

    A UC target material of 11.3±0.5 g/cm^3 uranium density with the grain size of 20 and 5μm manufactured in a form of pills by the method of powder metallurgy has been tested on-line within the temperature range of 1800-2100 ° C . The mass of uranium exposed to the beam was 4-7g. The yields and release rates of Cs and Fr isotopes produced by fission and spallation reactions of 238U by 1GeV protons have been measured. The yields of Cs and Fr isotopes obtained from the tested target materials have been compared, including yields of very short-lived Fr isotopes with half-lives down to 1ms. Temperature-resistant materials (porous graphite and tantalum foil) have been used for the internal-container construction, which holds the UC target pills inside a tungsten external container heated by the resistant heating. The fastest release and the highest efficiency for short-lived isotopes have been obtained for the targets with the internal container manufactured from the tantalum foil. Results of on-line tests of a big mass target (730g of 5μm grain UC target material) have been discussed.

  12. Assisted Living

    MedlinePlus

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  13. 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 ...

  14. 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.

  15. Conflicting Hf and Nd isotopic records of the Early Earth--But what about Pb?

    NASA Astrophysics Data System (ADS)

    Vervoort, J. D.

    2006-12-01

    The Sm-Nd and Lu-Hf isotope systems have been valuable tools in our understanding of the differentiation and evolution of bulk silicate Earth (BSE). Linking these systems is especially important for constraining the early history of the silicate Earth as they provide independent records in rocks with long and complex tectonothermal histories. These records, however, are currently in conflict. The Hf isotope record of the oldest terrestrial rocks and zircons, based on the most recent decay constants for Hf, is characterized by chondritic to negative initial ɛHf values [e.g., 1-3], indicating these rocks were derived from a source with a prior crustal history. In contrast, the Nd isotopic record of the oldest rocks are characterized by positive ɛNd values [e.g., 4], indicating these materials were derived from a mantle depleted in incompatible elements by a widespread differentiation event [4], rather than from pre-existing crust. The ^{143}Nd scenario is consistent with constraints from the short-lived isotope ^{146}Sm-^{142}Nd system [5] which indicate very early and widespread differentiation of the mantle and possibly sequestration of the enriched component to the inaccessible mantle, a view suggested nearly 20 years ago based on the long-lived Nd isotopic data record [6]. An important isotopic system that has been largely ignored in recent discussions is the U-Pb system. This system provides important constraints because of the two U-Pb decay paths and the shorter half-lives of the U isotopes relative to ^{147}Sm and ^{176}Lu. If there had been widespread crust formation throughout the Hadean and early Archean, this should be recorded in the Pb isotope signature of mantle derived samples. In the 2.7 Ga Abitibi Greenstone belt initial Pb isotopic compositions define a highly linear Pb/Pb isotope array whose slope corresponds to an age of ~4.4 Ga, nearly coincident with the 2.7 Ga geochron. This Pb/Pb array has a range in 207Pb/204Pb as large as in modern MORB, but 206Pb/204Pb variations only one-tenth as large. The U/Pb variations that produced these Pb isotopic relationships could only have been created very early in the Earth's history and also require that this mantle source had not been subsequently disturbed by crust extraction or additions from recycled crust from 4.4 to 2.7 Ga. In contrast, the initial Pb isotopic compositions of late Archean cratons where early Archean crust exists today (e.g., Slave, Pilbara) have Pb isotopic compositions displaced to the right of the 2.7 Ga Geochron toward higher 206Pb/204Pb, and indicate the presence of pre-2.7 Ga crust in their genesis. The simple observation from these data is that in late Archean terranes there is Pb isotopic evidence for early Archean crust where it is known to exist today and this Pb isotope evidence is lacking when early Archean crust is now physically absent. The Pb isotopic data, therefore, support the Nd isotopic records (both ^{142}Nd and ^{143}Nd) indicating early widespread mantle differentiation but scant evidence for the existence of an extensive, long-lived enriched reservoir at the surface of the Earth (i.e., continental crust) in the early Archean. [1] Vervoort and Blichert-Toft, GCA, 63: 533 (1999); [2] Amelin et al., Nature, 399: 252 (1999); [3] Harrison et al., Science, 310: 1947 (2005); [4] Shirey, Min. Assoc. Can., 19: 103 (1991); [5] Boyet and Carlson, Science, 309: 576 (2005); [6] Chase and Patchett, EPSL, 91:66 (1988).

  16. Effects of Geologically Short-Lived Surface Water Perturbations on the Calcareous Nannoplankton as Exemplified by the Paleocene-Eocene Thermal Maximum and Cretaceous Oceanic Anoxic Event OAE1d

    NASA Astrophysics Data System (ADS)

    Bralower, T. J.; Watkins, D. K.

    2007-12-01

    Calcareous nannoplankton are obligate photoautotrophs restricted to the photic zone in the open ocean. Disruptions to the chemical and physical structure of the surface water mass constitute the most important environmental stresses forcing evolutionary changes. Surface-water environmental perturbations in ancient oceans provide opportunities to test the effects of these stresses on ancient plankton communities. Here we present data from the Paleocene-Eocene Thermal Maximum (PETM) at 55 Ma and mid-Cretaceous (late Albian) oceanic anoxic event (OAE) 1d at 98 Ma, and compare changes in nannoplankton communities, including extinctions and originations (taxonomic turnover) and temporary assemblage shifts, with the extent and rate of change in environmental variables including temperature, thermal stratification, carbon export and alkalinity. In the case of the PETM, high rates of taxonomic turnover affected both oligotrophic and mesotrophic species. These taxa were relatively minor parts of the total assemblages, however, and the numerically abundant species were not affected permanently. The event is associated with a wholesale assemblage shift, including common and rare taxa, that varies from one oceanic setting to another. Highest rates of turnover and assemblage shift occurred during intervals when the rate of change of environmental variables including temperature, stratification and carbon export is highest. Relatively minor perturbations in the structure of the upper surface water mass, such as that associated with OAE1d, led to selective extinction of morphologically specialized oligotrophic taxa that were dependent upon maintaining a fixed position in a stable, stratified water column. These taxa were relatively rare components of the late Albian assemblages. In addition, the environmental changes associated with the anoxic event were coincident with originations and extinctions of less specialized clades undergoing adaptive radiation. These examples suggest that geologically brief perturbations of the upper water column affect only rare taxa permanently, while the more common calcareous nannoplankton exhibit a remarkable resilience to the effects of all but the most extreme short-lived disruptions of the surface water mass.

  17. Abrogation of SHP-1 in tumor-specific T cells improves efficacy of adoptive immunotherapy by enhancing the effector function and accumulation of short-lived effector T cells in vivo

    PubMed Central

    Stromnes, Ingunn M.; Fowler, Carla; Casamina, Chanel C.; Georgopolos, Christina M.; McAfee, Megan S.; Schmitt, Thomas M.; Tan, Xiaoxia; Kim, Tae-Don; Choi, Inpyo; Blattman, Joseph N.; Greenberg, Philip D.

    2012-01-01

    T cell expression of inhibitory proteins can be a critical component for the regulation of immunopathology due to self-reactivity or potentially exuberant responses to pathogens, but may also limit T cell responses to some malignancies, particularly if the tumor antigen being targeted is a self-protein. We found that the abrogation of SHP-1, in tumor-reactive CD8+ T cells improves the therapeutic outcome of adoptive immunotherapy in a mouse model of disseminated leukemia, with benefit observed in therapy employing transfer of CD8+ T cells alone or in the context of also providing supplemental IL-2. SHP-1−/− and SHP-1+/+ effector T cells were expanded in vitro for immunotherapy. Following transfer in vivo, the SHP-1−/− effector T cells exhibited enhanced short-term accumulation, followed by greater contraction, and ultimately formed similar numbers of long-lived, functional memory cells. The increased therapeutic effectiveness of SHP-1−/− effector cells was also observed in recipients that expressed the tumor antigen as a self-antigen in the liver, without evidence of inducing autoimmune toxicity. SHP-1−/− effector CD8+ T cells expressed higher levels of Eomesodermin, which correlated with enhanced lysis of tumor cells. Furthermore, reduction of SHP-1 expression in tumor-reactive effector T cells by retroviral transduction with vectors that express SHP-1-specific siRNA, a translatable strategy, also exhibited enhanced anti-tumor activity in vivo. These studies suggest that abrogating SHP-1 in effector T cells may improve the efficacy of tumor elimination by T cell therapy without impacting the ability of the effector cells to persist and provide a long-term response. PMID:22798667

  18. 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.

  19. 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).

  20. 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

  1. Zn isotope fractionation during adsorption on birnessite

    NASA Astrophysics Data System (ADS)

    Bryan, A. L.; Dong, S.; Wasylenki, L. E.

    2013-12-01

    The biogeochemical cycling of zinc (Zn), an important micronutrient in the ocean, may influence primary productivity and species composition within surface waters. The chemical speciation and bioavailability of Zn is governed by diverse abiotic and biotic processes. These processes include adsorption reactions at mineral/water interfaces, as nanoparticles of oxyhydroxide minerals are known to adsorb significant amounts of Zn in surface waters (and during formation of ferromanganese crusts). Investigation of Zn isotope fractionation caused by adsorption onto birnessite, the dominant manganese oxide mineral in ferromanganese crusts, may help to explain the enrichment of heavy Zn isotopes in ferromanganese crusts. This will provide insight into the role of adsorption of Zn to nanoparticulate minerals in surface waters and into the overall biogeochemical cycling of Zn. This work aims to determine the mechanism and magnitude of Zn isotope fractionation during adsorption onto synthetic birnessite (KMn2O4.1.5H2O). Our simple-system experiments involve mixing solutions of 130 ppb Zn with aliquots of birnessite suspension (proportions varied to give a range of surface coverage) and a fixed pH near that of seawater at ~8.5. The mixtures react for 48 hours. The recovered dissolved Zn and adsorbed Zn are then separated, purified, and analyzed isotopically on a Nu Plasma MC-ICP-MS. Preliminary results show enrichment of light Zn isotopes on the mineral surfaces (Δ66/64Znsorbed-aqueous = -0.3‰). A time series will reveal whether this process is governed by equilibrium or Rayleigh fractionation. Contrary to our results, previously published studies led us to hypothesize that isotopically heavy Zn would adsorb compared to co-existing dissolved Zn. Maréchal et al. (2000) recorded ferromanganese crusts that were heavier than seawater with a mean δ66Zn value of 0.90‰. Dissolved Zn is octahedrally coordinated with oxygen atoms, but an EXAFS study by Manceau et al. (2002) 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.

  2. 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.

  3. Nuclear orientation of on-line separated isotopes

    NASA Astrophysics Data System (ADS)

    Vandeplassche, D.; Vanneste, L.; Pattyn, H.; Geenen, J.; Nuytten, C.; van Walle, E.

    On-line techniques have proven to be successful for the study of nuclei far from stability in performing spectroscopy. Further information on these short-lived nuclei can be obtained by measuring anisotopy coefficients of β- and γ-transitions. These measurements permit the clarifying of decay schemes and the study of nuclear moments. We thus propose the combination of on-line mass-separation with low temperature nuclear orientation. A system for this is being set up at the LISOL facility. The main part consists of a 3He- 4He dilution cryostat with high cooling power. It features a side-access port to allow direct implantation on the cold finger. A liquid helium cooled transport line with adjustable baffles makes the connection to the isotope separator. Nuclei with a lifetime down to a few minutes can be continuously implanted into a ferromagnetic host and oriented by the hyperfine field at temperatures lower than 30 mK. The limit of the lifetime is set by the spin-lattice relaxation time. In order to study shorter lived nuclei an "on-line" immediate orienting mechanism is installed: the beam line includes a UHV-chamber, where polarization is achieved by scattering at grazing incidence on a magnetized nickel single crystal. For preserving the obtained orientation during measurement the low temperature implantation is still required. Both mentioned orienting mechanisms completement each other for a nuclear study of short-lived isotopes. Sets of deflection plates and a movable part of the beam line allow a quick transition from one mode to another. Furthermore the cooled collecting foils can be changed in a short time without breaking the cooling cycle it removal of the daughter activities is requested.

  4. 18O/ 16O mapping and hydrogeology of a short-lived (?10 years) fumarolic (>500C) meteoric-hydrothermal event in the upper part of the 0.76 Ma Bishop Tuff outflow sheet, California

    NASA Astrophysics Data System (ADS)

    Holt, Elizabeth Warner; Taylor, Hugh P.

    1998-07-01

    18O/ 16O data from the 200-m-thick, 0.76 Ma Bishop Tuff outflow sheet provide evidence for a vigorous, short-lived (?10 years), high-temperature, fumarolic meteoric-hydrothermal event. This is proved by: (1) the juxtaposition in the upper, partially welded Bishop Tuff of low- 18O groundmass/glass ( ?18O=-5 to +3) with coexisting quartz and feldspar phenocrysts having magmatic ?18O values (+8.70.3; +7.50.3); and (2) the fact that these kinds of 18O/ 16O signatures correlate very well with morphological features and mapped zones