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Sample records for rate electron capture

  1. Supernova electron capture rates

    CERN Document Server

    Martínez-Pinedo, G

    1999-01-01

    We have calculated the Gamow-Teller strength distributions for the ground states and low lying states of several nuclei that play an important role in the precollapse evolution of supernova. The calculations reproduce the experimental GT distributions nicely. The GT distribution are used to calculate electron capture rates for typical presupernova conditions. The computed rates are noticeably smaller than the presently adopted rates. The possible implications for the supernova evolution are discussed.

  2. Effects of Electron Screening on Electron Capture Rates in High Density Presupernova Core

    Institute of Scientific and Technical Information of China (English)

    蒋广飞; 彭秋和; 邹志刚

    2003-01-01

    Considering that the electron capture rate can be greatly reduced by the electron screening effect in the regime of high temperature and high density, we calculate the effect of electron screening on the electron capture rate for two important elements 56Ni and 55Co in the high density condition of a pre-supernova star. The effect of electron screening is so effective that the electron capture rate may be reduced to about 20%.

  3. Influence of electron screening on electron capture rate under high density of stellar interior

    Institute of Scientific and Technical Information of China (English)

    罗志全; 彭秋和

    1996-01-01

    The influence of electron screening on electron capture rate in strong screening is investigated, in which the Gamow-Teller resonance transition is considered and the matrix elements for the resonance transition are calculated on the basis of a shell model. The effect of electron screening on electron capture by 56Co is discussed. It is shown that the screening decreases evidently the capture rates in lower temperature and higher density. The effect of electron screening on other nuclear capture rates is estimated. The conclusion derived may influence the research for late stellar evolution and supernova explosion.

  4. Electron and Positron Capture Rates on $\\bf{^{55}}$Co in Stellar Matter

    CERN Document Server

    Nabi, Jameel-Un; Sajjad, Muhammad

    2014-01-01

    Cobalt-55 is not only present in abundance in presupernova phase but is also advocated to play a decisive role in the core collapse of massive stars. The spectroscopy of electron capture and emitted neutrinos yields useful information on the physical conditions and stellar core composition. B(GT) values to low-lying states are calculated microscopically using the pn-QRPA theory. Our rates are enhanced compared to the shell model rates. The enhancement is attributed partly to the liberty of selecting a huge model space, allowing consideration of many more parent excited states in our rate calculation. Unlike previous calculations, the so-called Brink's hypothesis is not assumed leading to a more realistic estimate of the rates. The electron and positron capture rates are calculated over a wide temperature and density grid.

  5. Nuclear electron capture rate in stellar interiors and the case of 7Be

    CERN Document Server

    Quarati, P

    2008-01-01

    Nuclear electron capture rate from continuum in an astrophysical plasma environment (like solar core) is calculated using a modified Debye-Huckel screening potential and the related non-Gaussian q-distribution of electron momenta. For q=1 the well-known Debye-Huckel results are recovered. The value of q can be derived from the fluctuation of number of particles and temperature inside the Debye sphere. For 7Be continuum electron capture in solar core, we find an increase of 7 -- 10 percent over the rate calculated with standard Debye-Huckel potential. The consequence of this results is a reduction of the same percentage of the SSM 8B solar neutrino flux, leaving unchanged the SSM 7Be flux.

  6. Stellar electron-capture rates calculated with the finite-temperature relativistic random-phase approximation

    CERN Document Server

    Niu, YiFei; Vretenar, Dario; Meng, Jie

    2011-01-01

    We introduce a self-consistent microscopic theoretical framework for modelling the process of electron capture on nuclei in stellar environment, based on relativistic energy density functionals. The finite-temperature relativistic mean-field model is used to calculate the single-nucleon basis and the occupation factors in a target nucleus, and $J^{\\pi} = 0^{\\pm}$, $1^{\\pm}$, $2^{\\pm}$ charge-exchange transitions are described by the self-consistent finite-temperature relativistic random-phase approximation. Cross sections and rates are calculated for electron capture on 54,56Fe and 76,78Ge in stellar environment, and results compared with predictions of similar and complementary model calculations.

  7. Stellar electron capture rates on neutron-rich nuclei and their impact on core-collapse

    CERN Document Server

    Raduta, Ad R; Oertel, M

    2016-01-01

    During the late stages of gravitational core-collapse of massive stars, extreme isospin asymmetries are reached within the core. Due to the lack of microscopic calculations of electron capture (EC) rates for all relevant nuclei, in general simple analytic parameterizations are employed. We study here several extensions of these parameterizations, allowing for a temperature, electron density and isospin dependence as well as for odd-even effects. The latter extra degrees of freedom considerably improve the agreement with large scale microscopic rate calculations. We find, in particular, that the isospin dependence leads to a significant reduction of the global EC rates during core collapse with respect to fiducial results, where rates optimized on calculations of stable $fp$-shell nuclei are used. Our results indicate that systematic microscopic calculations and experimental measurements in the $N\\approx 50$ neutron rich region are desirable for realistic simulations of the core-collapse.

  8. Fine-grid calculations for stellar electron and positron capture rates on Fe isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Nabi, Jameel-Un, E-mail: jameel@giki.edu.pk [Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Faculty of Engineering Sciences (Pakistan); Tawfik, Abdel Nasser, E-mail: a.tawfik@eng.mti.edu.eg [MTI University, Egyptian Center for Theoretical Physics (ECTP) (Egypt)

    2013-03-15

    The acquisition of precise and reliable nuclear data is a prerequisite to success for stellar evolution and nucleosynthesis studies. Core-collapse simulators find it challenging to generate an explosion from the collapse of the core of massive stars. It is believed that a better understanding of the microphysics of core-collapse can lead to successful results. The weak interaction processes are able to trigger the collapse and control the lepton-to-baryon ratio (Y{sub e}) of the corematerial. It is suggested that the temporal variation of Y{sub e} within the core of a massive star has a pivotal role to play in the stellar evolution and a fine-tuning of this parameter at various stages of presupernova evolution is the key to generate an explosion. During the presupernova evolution of massive stars, isotopes of iron, mainly {sup 54-56}Fe, are considered to be key players in controlling Y{sub e} ratio via electron capture on these nuclides. Recently an improved microscopic calculation of weak-interaction-mediated rates for iron isotopes was introduced using the proton-neutron quasiparticle random-phase-approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic state-by-state calculation of stellar capture rates which greatly increases the reliability of calculated rates. The results were suggestive of some fine-tuning of the Y{sub e} ratio during various phases of stellar evolution. Here we present for the first time the fine-grid calculation of the electron and positron capture rates on {sup 54-56}Fe. The sensitivity of the pn-QRPA calculated capture rates to the deformation parameter is also studied in this work. Core-collapse simulators may find this calculation suitable for interpolation purposes and for necessary incorporation in the stellar evolution codes.

  9. Electron Capture and Beta-Decay Rates for the Collapse of O+Ne+Mg Cores

    Directory of Open Access Journals (Sweden)

    Hua Lam Yi

    2014-03-01

    Full Text Available We present a new set of electron (e− capture and β-decay rates that improves previous calculations by Takahara et al. and Oda et al. by: (a incorporation of recent charge-exchange and β-decay data, (b contributions of forbidden transitions, and (c inclusion of e− screening corrections. The experimental nuclear input is supplemented by theoretical data based on large-scale shell model calculations in the full sd-shell space using the USDB interaction. The impact of these new rates on the late-stage stellar evolution of 8.8M⊙ star is demonstrated.

  10. Oscillating decay rate in electron capture and the neutrino mass difference

    Energy Technology Data Exchange (ETDEWEB)

    Peshkin, Murray

    2015-04-09

    Reported oscillations in the rate of decay of certain ions by K -electron capture have raised questions about whether and how such oscillations can arise in quantum-mechanical theory and whether they can measure the neutrino mass difference. Here I show that simple principles of quantum mechanics answer some questions and clarify what must be performed theoretically or experimentally to answer some others. The principal result is that quantum mechanics does allow mass-difference-dependent oscillations in principle, but it imposes conditions not obeyed by the approximate dynamical models that have been put forth up to now. In particular, indirect coupling between two neutrino mass channels must be taken into account. What needs to be done experimentally and theoretically is discussed.

  11. Oscillating decay rate in electron capture and the neutrino mass difference

    Science.gov (United States)

    Peshkin, Murray

    2015-04-01

    Reported oscillations in the rate of decay of certain ions by K -electron capture have raised questions about whether and how such oscillations can arise in quantum-mechanical theory and whether they can measure the neutrino mass difference. Here I show that simple principles of quantum mechanics answer some questions and clarify what must be performed theoretically or experimentally to answer some others. The principal result is that quantum mechanics does allow mass-difference-dependent oscillations in principle, but it imposes conditions not obeyed by the approximate dynamical models that have been put forth up to now. In particular, indirect coupling between two neutrino mass channels must be taken into account. What needs to be done experimentally and theoretically is discussed.

  12. Electron capture rates in stars studied with heavy ion charge exchange reactions

    CERN Document Server

    Bertulani, C A

    2015-01-01

    Indirect methods using nucleus-nucleus reactions at high energies (here, high energies mean $\\sim$ 50 MeV/nucleon and higher) are now routinely used to extract information of interest for nuclear astrophysics. This is of extreme relevance as many of the nuclei involved in stellar evolution are short-lived. Therefore, indirect methods became the focus of recent studies carried out in major nuclear physics facilities. Among such methods, heavy ion charge exchange is thought to be a useful tool to infer Gamow-Teller matrix elements needed to describe electron capture rates in stars and also double beta-decay experiments. In this short review, I provide a theoretical guidance based on a simple reaction model for charge exchange reactions.

  13. Modification of magicity towards the dripline and its impact on electron-capture rates for stellar core-collapse

    CERN Document Server

    Raduta, Ad R; Oertel, M

    2015-01-01

    The importance of microphysical inputs from laboratory nuclear experiments and theoretical nuclear structure calculations in the understanding of the core collapse dynamics, and the subsequent supernova explosion, is largely recognized in the recent literature. In this work, we analyze the impact of the masses of very neutron rich nuclei on the matter composition during collapse, and the corresponding electron capture rate. To this aim, we introduce an empirical modification of the popular Duflo-Zuker mass model to account for possible shell quenching far from stability, and study the effect of the quenching on the average electron capture rate. We show that the preeminence of the $N=50$ and $N=82$ closed shells in the collapse dynamics is considerably decreased if the shell gaps are reduced in the region of $^{78}$Ni and beyond. As a consequence, local modifications of the overall electron capture rate up to 30\\% can be expected, with integrated values strongly dependent on the stiffness of magicity quenchin...

  14. Fine-Grid Calculations for Stellar Electron and Positron Capture Rates on Fe-Isotopes

    CERN Document Server

    Nabi, Jameel-Un

    2011-01-01

    The acquisition of precise and reliable nuclear data is a prerequisite to success for stellar evolution and nucleosynthesis studies. Core-collapse simulators find it challenging to generate an explosion from the collapse of the core of massive stars. It is believed that a better understanding of the microphysics of core-collapse can lead to successful results. The weak interaction processes are able to trigger the collapse and control the lepton-to-baryon ratio ($Y_{e}$) of the core material. It is suggested that the temporal variation of $Y_{e}$ within the core of a massive star has a pivotal role to play in the stellar evolution and a fine-tuning of this parameter at various stages of presupernova evolution is the key to generate an explosion. During the presupernova evolution of massive stars, isotopes of iron, mainly $^{54,55,56}$Fe, are considered to be key players in controlling $Y_{e}$ ratio via electron capture on these nuclide. Recently an improved microscopic calculation of weak interaction mediated...

  15. Detailed microscopic calculation of stellar electron and positron capture rates on $^{24}$Mg for O+Ne+Mg core simulations

    CERN Document Server

    Nabi, Jameel-Un

    2014-01-01

    Few white dwarfs, located in binary systems, may acquire sufficiently high mass accretion rates resulting in the burning of carbon and oxygen under nondegenerate conditions forming a O+Ne+Mg core. These O+Ne+Mg cores are gravitationally less bound than more massive progenitor stars and can release more energy due to the nuclear burning. They are also amongst the probable candidates for low entropy r-process sites. Recent observations of subluminous Type II-P supernovae (e.g., 2005cs, 2003gd, 1999br, 1997D) were able to rekindle the interest in 8 -- 10 M$_{\\odot}$ which develop O+Ne+Mg cores. Microscopic calculations of capture rates on $^{24}$Mg, which may contribute significantly to the collapse of O+Ne+Mg cores, using shell model and proton-neutron quasiparticle random phase approximation (pn-QRPA) theory, were performed earlier and comparisons made. Simulators, however, may require these capture rates on a fine scale. For the first time a detailed microscopic calculation of the electron and positron captur...

  16. Stellar electron-capture rates in pf-shell nuclei from quasiparticle random-phase approximation calculations

    CERN Document Server

    Sarriguren, P

    2013-01-01

    Electron-capture rates at different density and temperature conditions are evaluated for a set of pf-shell nuclei representative of the constituents in presupernova formations. The nuclear structure part of the problem is described within a quasiparticle random-phase approximation based on a deformed Skyrme Hartree-Fock selfconsistent mean field with pairing correlations and residual interactions in particle-hole and particle-particle channels. The energy distributions of the Gamow-Teller strength are evaluated and compared to benchmark shell-model calculations and experimental data extracted from charge-exchange reactions. The model dependence of the weak rates are discussed and the various sensitivities to both density and temperature are analyzed.

  17. Electron-capture decay rate of 7Be@C60 by first-principles calculations based on density functional theory

    NARCIS (Netherlands)

    Morisato, T.; Ohno, K.; Ohtsuki, T.; Hirose, K.; Sluiter, M.; Kawazoe, Y.

    2008-01-01

    Carrying out a first-principles calculation assuming linear relationship between the electron density at Be nucleus and the electron-capture (EC) decay rate, we explained why 7Be@C60 shows higher EC decay rate than 7Be crystal, which was originally found experimentally by Ohtsuki et al. [Phys. Rev.

  18. On neutrinoless double electron capture

    CERN Document Server

    Drukarev, E G

    2016-01-01

    We found the probability for the neutrinoless double electron capture in the case of $KK$ capture. We clarified the mechanism of the energy transfer from the nucleus to the bound electrons. This enabled us to obtain the equations for the probability of the $2EC0\

  19. Electron capture and beta-decay rates for sd-shell nuclei in stellar environments relevant to high density O-Ne-Mg cores

    CERN Document Server

    Suzuki, Toshio; Nomoto, Ken'ichi

    2015-01-01

    Electron capture and beta-decay rates for nuclear pairs in sd-shell are evaluated at high densities and high temperatures relevant to the final evolution of electron-degenerate O-Ne-Mg cores of stars with the initial masses of 8-10 solar mass. Electron capture induces a rapid contraction of the electron-degenerate O-Ne-Mg core. The outcome of rapid contraction depends on the evolutionary changes in the central density and temperature, which are determined by the competing processes of contraction, cooling, and heating. The fate of the stars are determined by these competitions, whether they end up with electron-capture supernovae or Fe core-collapse supernovae. Since the competing processes are induced by electron capture and beta-decay, the accurate weak rates are crucially important. The rates are obtained for pairs with A=20, 23, 24, 25 and 27 by shell-model calculations in sd-shell with the USDB Hamiltonian. Effects of Coulomb corrections on the rates are evaluated. The rates for pairs with A=23 and 25 ar...

  20. ELECTRON-CAPTURE AND β-DECAY RATES FOR sd-SHELL NUCLEI IN STELLAR ENVIRONMENTS RELEVANT TO HIGH-DENSITY O–NE–MG CORES

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Toki, Hiroshi [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Nomoto, Ken’ichi, E-mail: suzuki@phys.chs.nihon-u.ac.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

    2016-02-01

    Electron-capture and β-decay rates for nuclear pairs in the sd-shell are evaluated at high densities and high temperatures relevant to the final evolution of electron-degenerate O–Ne–Mg cores of stars with initial masses of 8–10 M{sub ⊙}. Electron capture induces a rapid contraction of the electron-degenerate O–Ne–Mg core. The outcome of rapid contraction depends on the evolutionary changes in the central density and temperature, which are determined by the competing processes of contraction, cooling, and heating. The fate of the stars is determined by these competitions, whether they end up with electron-capture supernovae or Fe core-collapse supernovae. Since the competing processes are induced by electron capture and β-decay, the accurate weak rates are crucially important. The rates are obtained for pairs with A = 20, 23, 24, 25, and 27 by shell-model calculations in the sd-shell with the USDB Hamiltonian. Effects of Coulomb corrections on the rates are evaluated. The rates for pairs with A = 23 and 25 are important for nuclear Urca processes that determine the cooling rate of the O–Ne–Mg core, while those for pairs with A = 20 and 24 are important for the core contraction and heat generation rates in the core. We provide these nuclear rates at stellar environments in tables with fine enough meshes at various densities and temperatures for studies of astrophysical processes sensitive to the rates. In particular, the accurate rate tables are crucially important for the final fates of not only O–Ne–Mg cores but also a wider range of stars, such as C–O cores of lower-mass stars.

  1. Electron capture in carbon dwarf supernovae

    Science.gov (United States)

    Mazurek, T. J.; Truran, J. W.; Cameron, A. G. W.

    1974-01-01

    The rates of electron capture on heavier elements under the extreme conditions predicted for dwarf star supernovae have been computed, incorporating modifications that seem to be indicated by present experimental results. An estimate of the maximum possible value of such rates is also given. The distribution of nuclei in nuclear statistical equilibrium has been calculated for the range of expected supernovae conditions, including the effects of the temperature dependence of nuclear partition functions. These nuclide abundance distributions are then used to compute nuclear equilibrium thermodynamic properties. The effects of the electron capture on such equilibrium matter are discussed. In the context of the 'carbon detonation' supernova model, the dwarf central density required to ensure core collapse to a neutron star configuration is found to be slightly higher than that obtained by Bruenn (1972) with the electron capture rates of Hansen (1966).-

  2. Comparative study of Gamow-Teller strength distributions in the odd-odd nucleus 50V and its impact on electron capture rates in astrophysical environments

    CERN Document Server

    Nabi, Jameel-Un; 10.1103/PhysRevC.76.055803

    2011-01-01

    Gamow-Teller (GT) strength transitions are an ideal probe for testing nuclear structure models. In addition to nuclear structure, GT transitions in nuclei directly affect the early phases of Type Ia and Type-II supernovae core collapse since the electron capture rates are partly determined by these GT transitions. In astrophysics, GT transitions provide an important input for model calculations and element formation during the explosive phase of a massive star at the end of its life-time. Recent nucleosynthesis calculations show that odd-odd and odd-A nuclei cause the largest contribution in the rate of change of lepton-to-baryon ratio. In the present manuscript, we have calculated the GT strength distributions and electron capture rates for odd-odd nucleus 50V by using the pn-QRPA theory. At present 50V is the first experimentally available odd-odd nucleus in fp-shell nuclei. We also compare our GT strength distribution with the recently measured results of a 50V(d,2He)50Ti experiment, with the earlier work ...

  3. Electron capture cross sections for stellar nucleosynthesis

    CERN Document Server

    Giannaka, P G

    2015-01-01

    In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasi-particle random-phase approximation (pn-QRPA) and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the above mentioned $e^-$-capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the $^{66}Zn$ isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  4. Testing Lorentz invariance in orbital electron capture

    CERN Document Server

    Vos, K K; Timmermans, R G E

    2015-01-01

    Searches for Lorentz violation were recently extended to the weak sector, in particular neutron and nuclear $\\beta$ decay [1]. From experiments on forbidden $\\beta$-decay transitions strong limits in the range of $10^{-6}$-$10^{-8}$ were obtained on Lorentz-violating components of the $W$-boson propagator [2]. In order to improve on these limits strong sources have to be considered. In this Brief Report we study isotopes that undergo orbital electron capture and allow experiments at high decay rates and low dose. We derive the expressions for the Lorentz-violating differential decay rate and discuss the options for competitive experiments and their required precision.

  5. Comparative study of Gamow-Teller strength distributions in the odd-odd nucleus V50 and its impact on electron capture rates in astrophysical environments

    Science.gov (United States)

    Nabi, Jameel-Un; Sajjad, Muhammad

    2007-11-01

    Gamow-Teller (GT) strength transitions are an ideal probe for testing nuclear structure models. In addition to nuclear structure, GT transitions in nuclei directly affect the early phases of Type Ia and Type-II supernovae core collapse since the electron capture rates are partly determined by these GT transitions. In astrophysics, GT transitions provide an important input for model calculations and element formation during the explosive phase of a massive star at the end of its life-time. Recent nucleosynthesis calculations show that odd-odd and odd-A nuclei cause the largest contribution in the rate of change of lepton-to-baryon ratio. In the present manuscript, we have calculated the GT strength distributions and electron capture rates for odd-odd nucleus V50 by using the pn-QRPA theory. At present V50 is the first experimentally available odd-odd nucleus in fp-shell nuclei. We also compare our GT strength distribution with the recently measured results of a V50(d, He2)Ti50 experiment, with the earlier work of Fuller, Fowler, and Newman (referred to as FFN) and subsequently with the large-scale shell model calculations. One curious finding of the paper is that the Brink's hypothesis, usually employed in large-scale shell model calculations, is not a good approximation to use at least in the case of V50. SNe Ia model calculations performed using FFN rates result in overproduction of Ti50, and were brought to a much acceptable value by employing shell model results. It might be interesting to study how the composition of the ejecta using presently reported QRPA rates compare with the observed abundances.

  6. Sensitivity of stellar electron-capture rates to parent neutron number: A case study on a continuous chain of twenty Vanadium isotopes

    CERN Document Server

    Hitt, G W; Zegers, R G T; Titus, R; Sullivan, C; Brown, B A; Cole, A L; Shams, S

    2016-01-01

    Gamow-Teller (GT) strength distributions (B(GT)) in electron-capture (EC) daughters stemming from the parent ground state are computed with the shell-model in the full pf-shell space, with quasi-particle random-phase approximation (QRPA) in the formalism of Krumlinde and M\\"oller and with an Approximate Method (AM) for assigning an effective B(GT). These are compared to data available from decay and charge-exchange (CE) experiments across titanium isotopes in the pf-shell from A=43 to A=62, the largest set available for any chain of isotopes in the pf-shell. The present study is the first to examine B(GT) and the associated EC rates across a particular chain of isotopes with the purpose of examining rate sensitivities as neutron number increases. EC rates are also computed for a wide variety of stellar electron densities and temperatures providing concise estimates of the relative size of rate sensitivities for particular astrophysical scenarios. This work underscores the astrophysical motivation for CE exper...

  7. Electron Capture in a Fully Ionized Plasma

    CERN Document Server

    Widom, A; Srivastava, Y N

    2014-01-01

    Properties of fully ionized water plasmas are discussed including plasma charge density oscillations and the screening of the Coulomb law especially in the dilute classical Debye regime. A kinetic model with two charged particle scattering events determines the transition rate per unit time for electron capture by a nucleus with the resulting nuclear transmutations. Two corrections to the recent Maiani et al. calculations are made: (i) The Debye screening length is only employed within its proper domain of validity. (ii) The WKB approximation employed by Maiani in the long De Broglie wave length limit is evidently invalid. We replace this incorrect approximation with mathematically rigorous Calogero inequalities in order to discuss the scattering wave functions. Having made these corrections, we find a verification for our previous results based on condensed matter electro-weak quantum field theory for nuclear transmutations in chemical batteries.

  8. Electron capture from coherent elliptic Rydberg states

    Energy Technology Data Exchange (ETDEWEB)

    Day, J.C.; DePaola, B.D.; Ehrenreich, T.; Hansen, S.B.; Horsdal-Pedersen, E.; Leontiev, Y.; Mogensen, K.S. [Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

    1997-12-01

    Experimental relative cross sections for electron capture by singly charged ions (Na{sup +}) from coherent elliptic states of principal quantum number n=25 are presented. An interval of reduced impact velocities from about 1{endash}2 is covered. Absolute reaction cross sections could not be determined precisely, but the eccentricity of the coherent elliptic states and their orientation relative to the ion-impact velocity were varied to expose the dependence of the electron-capture process on the initial motion of the electron. The dependencies on eccentricity and orientation are generally strong and they vary sharply with impact velocity. Qualitatively, the observations agree fairly well with classical trajectory Monte Carlo (CTMC) calculations, as expected for the large quantum numbers involved, but significant deviations of a systematic nature do remain, showing that some aspects of the capture reactions studied are described poorly by classical physics as represented by the CTMC model. {copyright} {ital 1997} {ital The American Physical Society}

  9. Muon capture rates within the projected QRPA

    CERN Document Server

    Santos, Danilo Sande; Krmpotić, Francisco; Dimarco, Alejandro J

    2012-01-01

    The conservation of the number of particles within the QRPA plays an important role in the evaluation muon capture rates in all light nuclei with A \\precsim 30 . The violation of the CVC by the Coulomb field in this mass region is of minor importance, but this effect could be quite relevant for medium and heavy nuclei studied previously. The extreme sensitivity of the muon capture rates on the 'pp' coupling strength in nuclei with large neutron excess when described within the QRPA is pointed out. We reckon that the comparison between theory and data for the inclusive muon capture is not a fully satisfactory test on the nuclear model that is used. The exclusive muon transitions are much more robust for such a purpose.

  10. Systematic muon capture rates in PQRPA

    Energy Technology Data Exchange (ETDEWEB)

    Samana, A. R. [Departamento de Ciências Exatas e Tecnológicas, UESC-Br (Brazil); Sande, D. [Instituto de Geociências, UFBA-Br (Brazil); Krmpotić, F. [Instituto de Física La Plata, CONICET-Ar and Fac. de Cs. Astronómicas y Geofísicas, UNLP-Ar (Argentina)

    2015-05-15

    In this work we performed a systematic study of the inclusive muon capture rates for several nuclei with A < 60 using the Projected Random Quasi-particle Phase Approximation (PQRPA) as nuclear model, because it is the only RPA model that treats the Pauli Principle correctly. We reckon that the comparison between theory and data for the inclusive muon capture is not a fully satisfactory test on the nuclear model that is used. The exclusive muon transitions are more robust for such a purpose.

  11. Double electron capture searches in $^{74}$Se

    CERN Document Server

    Lehnert, B; Degering, D; Sommer, D; Wagner, L; Zuber, K

    2016-01-01

    A search for various double electron capture modes of $^{74}$Se has been performed using an ultralow background Ge-detector in the Felsenkeller laboratory, Germany. Especially for the potentially resonant transition into the 1204.2 keV excited state of $^{74}$Ge a lower half-life limit of $0.70\\cdot 10^{19}$ yr (90% credibility) has been obtained. Serious concerns are raised about the validity of obtained $^{74}$Se limits in some recent publications.

  12. Measuring radiative capture rates at DRAGON

    Science.gov (United States)

    Hager, U.; Davids, B.; Fallis, J.; Greife, U.; Hutcheon, D. A.; Rojas, A.; Ruiz, C.

    2013-04-01

    The DRAGON recoil separator facility is located at the ISAC facility at TRIUMF, Vancouver. It is designed to measure radiative alpha and proton capture reactions of astrophysical importance in inverse kinematics. The Supernanogan ion source at ISAC provides stable beams of high intensities. The DRAGON collaboration has taken advantage of this over the last years by measuring several reactions requiring high-intensity stable oxygen beams. In particular,the ^17O(p,γ) and ^16O(α,γ) reaction rates were recently measured. The former reaction is part of the hot CNO cycle, and strongly influences the abundance of ^18F in classical novae. Because of its relatively long lifetime, ^18F is a possible target for satellite-based gamma-ray spectroscopy. The ^16O(α,γ) reaction plays a role in steady-state helium burning in massive stars, where it follows the ^12C(α,γ) reaction. At astrophysically relevant energies, the reaction proceeds exclusively via direct capture, resulting in a low rate. In both cases, the unique capabilities of DRAGON enabled determination not only of the total reaction rates, but also of decay branching ratios. Results from both experiments will be presented.

  13. Calculation of fractional electron capture probabilities

    CERN Document Server

    Schoenfeld, E

    1998-01-01

    A 'Table of Radionuclides' is being prepared which will supersede the 'Table de Radionucleides' formerly issued by the LMRI/LPRI (France). In this effort it is desirable to have a uniform basis for calculating theoretical values of fractional electron capture probabilities. A table has been compiled which allows one to calculate conveniently and quickly the fractional probabilities P sub K , P sub L , P sub M , P sub N and P sub O , their ratios and the assigned uncertainties for allowed and non-unique first forbidden electron capture transitions of known transition energy for radionuclides with atomic numbers from Z=3 to 102. These results have been applied to a total of 28 transitions of 14 radionuclides ( sup 7 Be, sup 2 sup 2 Na, sup 5 sup 1 Cr, sup 5 sup 4 Mn, sup 5 sup 5 Fe, sup 6 sup 8 Ge , sup 6 sup 8 Ga, sup 7 sup 5 Se, sup 1 sup 0 sup 9 Cd, sup 1 sup 2 sup 5 I, sup 1 sup 3 sup 9 Ce, sup 1 sup 6 sup 9 Yb, sup 1 sup 9 sup 7 Hg, sup 2 sup 0 sup 2 Tl). The values are in reasonable agreement with measure...

  14. Neutrino Signals in Electron-Capture Storage-Ring Experiments

    Directory of Open Access Journals (Sweden)

    Avraham Gal

    2016-06-01

    Full Text Available Neutrino signals in electron-capture decays of hydrogen-like parent ions P in storage-ring experiments at GSI are reconsidered, with special emphasis placed on the storage-ring quasi-circular motion of the daughter ions D in two-body decays P → D + ν e . It is argued that, to the extent that daughter ions are detected, these detection rates might exhibit modulations with periods of order seconds, similar to those reported in the GSI storage-ring experiments for two-body decay rates. New dedicated experiments in storage rings, or using traps, could explore these modulations.

  15. Scalable sensing electronics towards a motion capture suit

    Science.gov (United States)

    Xu, Daniel; Gisby, Todd A.; Xie, Shane; Anderson, Iain A.

    2013-04-01

    Being able to accurately record body motion allows complex movements to be characterised and studied. This is especially important in the film or sport coaching industry. Unfortunately, the human body has over 600 skeletal muscles, giving rise to multiple degrees of freedom. In order to accurately capture motion such as hand gestures, elbow or knee flexion and extension, vast numbers of sensors are required. Dielectric elastomer (DE) sensors are an emerging class of electroactive polymer (EAP) that is soft, lightweight and compliant. These characteristics are ideal for a motion capture suit. One challenge is to design sensing electronics that can simultaneously measure multiple sensors. This paper describes a scalable capacitive sensing device that can measure up to 8 different sensors with an update rate of 20Hz.

  16. Astrophysical neutron capture rates in s- and r-process nucleosynthesis

    CERN Document Server

    Beer, H; Oberhummer, Heinz; Rauscher, T; Mutti, P; Corvi, F; Sedyshev, P V; Popov, Yu P; Popov, Yu.P.

    1997-01-01

    Astrophysical neutron capture rates of light and heavy nuclei have been measured and calculated. For the measurements the activation technique was applied at the 3.75 MV Karlsruhe Van de Graaff accelerator, and at the Geel electron linear accelerator (GELINA) the time-of-flight (TOF) method was used. The calculations were performed using direct and compound nuclear capture models.

  17. Simulations of electron capture supernovae with approximate neutrino transport

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Heiko [TU Darmstadt (Germany); Fischer, Tobias [University of Wroclaw (Poland); Jones, Sam [Keele University (United Kingdom); Martinez-Pinedo, Gabriel [TU Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

    2014-07-01

    We have performed simulations of electron capture supernovae in a spherically symmetric general relativistic radiation hydrodynamics model with approximate neutrino treatment. We base our study on an 8.8 M {sub CircleDot} O-Ne-Mg core progenitor (Nomoto, 1984, 1987). We successfully obtain an explosion and compare our results with a reference run performed with an state-of-the-art three-flavor Boltzmann neutrino transport scheme implemented into the same hydrodynamic code. In general, we find good agreement in the the electron-flavor neutrino spectra. However, we find shorter explosion timescales and also significantly lower explosion energies of only 1.4 . 10{sup 48} erg. This result is in agreement with the explosion energy of SN 2008S as derived by Tominaga et al. (2013) based on light curve studies. Currently we are extending our simulations to the recently published super-AGB star progenitor models by Jones et al. (2013) with regard to their evolution towards an electron capture supernova. Our study also explores the role of weak interaction rates in determining the evolution and shaping the spectra of the emitted neutrinos.

  18. CP-violation reach of an electron capture neutrino beam

    CERN Document Server

    Orme, Christopher

    2009-01-01

    This article extends the work of Bernabeu and Espinoza by examining the CP-violation reach of a $^{150}$Dy electron capture beam through the variation of the two Lorentz boosts, the number of useful electron capture decays, the relative run time of each boost and the number of atmospheric backgrounds. The neutrinos are assumed to be sourced at CERN with an upgraded SPS and are directed towards a 440 kton Water Cerenkov detector located at the Canfranc laboratory. Two large `CP-coverage' choices for the boost pairings are found; a $\\delta$-symmetrical coverage for $(\\gamma_{1}, \\gamma_{2})$ = (280, 160) and an $\\delta$-asymmetric coverage for $(\\gamma_{1}, \\gamma_{2})$ = (440,150). With a nominal useful decay rate of $N_{\\rm ions} = 10^{18}$ per year, the $\\delta$-symmetric setup can rule out CP-conservation down to $\\sin^{2}2\\theta_{13} = 3\\cdot 10^{-4}$. To reach $\\sin^{2}2\\theta_{13} = 1\\cdot 10^{-3}$ for both $\\delta 0$ requires a useful decay rate of $N_{\\rm ions} = 6\\cdot 10^{17}$ per year.

  19. CP-violation reach of an electron capture neutrino beam

    Science.gov (United States)

    Orme, Christopher

    2010-07-01

    This article extends the work of Bernabeu and Espinoza by examining the CP-violation reach of a 150Dy electron capture beam through the variation of the two Lorentz boosts, the number of useful electron capture decays, the relative run time of each boost and the number of atmospheric backgrounds. The neutrinos are assumed to be sourced at CERN with an upgraded SPS and are directed towards a 440 kton Water Cerenkov detector located at the Canfranc laboratory. Two large ‘CP-coverage’ choices for the boost pairings are found; a δ-symmetrical coverage for ( γ 1, γ 2) = (280, 160) and an δ-asymmetric coverage for ( γ 1 , γ 2) = (440,150). With a nominal useful decay rate of N ions = 1018 ions per year, the δ-symmetric setup can rule out CP-conservation down to sin2 2 θ 13 = 3•10-4. To reach sin2 2 θ 13 =1•10-3 for both δ 0 requires a useful decay rate of N ions = 6•1017 ions per year.

  20. Single ionization and electron capture in He2++Na collisions

    NARCIS (Netherlands)

    Knoop, S; Olson, RE; Ott, H; Hasan, VG; Morgenstern, R; Hoekstra, R

    2005-01-01

    Single-electron capture and ionization in He2+ + Na collisions at energies around the matching velocity (2-13 keV amu(-1)) have been studied both experimentally and theoretically. State-selective cross section for capture into the n = 2, 3, 4 and n >= 5, and the ionization cross section as well as d

  1. Electron Capture Dissociation of Trivalent Metal Ion-Peptide Complexes

    National Research Council Canada - National Science Library

    Flick, Tawnya G; Donald, William A; Williams, Evan R

    2013-01-01

    .... ECD of these doubly charged complexes containing MT results in significantly higher electron capture efficiency and sequence coverage than peptide-divalent metal ion complexes that have the same net charge...

  2. Investigation of the electron capture process in semiclassical plasma

    Directory of Open Access Journals (Sweden)

    Seisembayeva Madina M.

    2016-06-01

    Full Text Available In this work, the process of electron capture in partially ionized plasma is considered. Electron-atom interaction was described by the effective interaction potential, which takes into account the screening effect at large distances and the diffraction effect at the small distances. The results of numerical calculations of the electron capture radius, differential cross-section for different values of the coupling and density parameters are presented. The differential cross-section was obtained on the basis of perturbation theory and also by solving of the equation of motion of the projectile electron.

  3. Resonant electron capture by orotic acid molecules

    Science.gov (United States)

    Muftakhov, M. V.; Shchukin, P. V.; Khatymov, R. V.

    2017-09-01

    Resonant electron attachment by orotic acid molecules (6-COOH-uracil) are studied in the energy range of 0-14 eV via negative ion mass spectrometry. Molecular ions, whose lifetimes relative to electron autodetachment are found to be 300 μs are recorded in the region of thermal electron energies; they form in the valence state through a vibration-excited resonance mechanism. Unlike unsubstituted uracil, most dissociative processes occur in the low-energy region of <4 eV and are due to carboxylic anions. An absolute cross section of 2.4 × 10-17 cm2 is found for the most intense fragment ions [M-H]- at an output energy of 1.33 eV. The kinetics of decarboxylation is considered for these ions. This could be a model reaction for the last stage of uridine monophosphate biosynthesis.

  4. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  5. Neutrino Mass, Electron Capture and the Shake-off Contributions

    CERN Document Server

    Faessler, Amand; Simkovic, Fedor

    2016-01-01

    Electron capture can determine the electron neutrino mass, while the beta decay of Tritium measures the electron antineutrino mass and the neutrinoless double beta decay observes the Majorana neutrino mass. Electron capture e. g. on 163Ho plus bound electron to 163Dy* plus neutrino can determine the electron neutrino mass from the upper end of the decay spectrum of the excited Dy*, which is given by the Q-Value minus the neutrino mass. The Dy* states decay by X-ray and Auger electron emissions. The total decay energy is measured in a bolometer. These excitations have been studied by Robertson and by Faessler et al.. In addition the daughter atom Dy can also be excited by moving in the capture process one electron into the continuum. The escape of these continuum electrons is automatically included in the experimental bolometer spectrum. Recently a method developed by Intemann and Pollock was used by DeRujula and Lusignoli for a rough estimate of this shake-off process for "s" wave electrons in capture on 163H...

  6. Double-electron capture by highly-ionized atoms isolated at very low energy

    Science.gov (United States)

    Fogwell Hoogerheide, Shannon; Dreiling, Joan M.; Sahiner, Arda; Tan, Joseph N.

    2016-05-01

    Charge exchange with background gases, also known as electron capture processes, is important in the study of comets, controlled fusion energy, anti-matter atoms, and proposed one-electron ions in Rydberg states. However, there are few experiments in the very low energy regime that could be useful for further theoretical development. At NIST, highly-charged ions extracted from an electron-beam ion trap can be isolated with energy state. Analysis using a system of rate equations yields information about the ion cloud expansion and single-electron capture rates. A substantial amount of double-electron capture is also observed. We present the relative rates and discuss the error budget. SFH and JMD were funded by National Research Council Research Associateship Awards during some of this work.

  7. Level-resolved quantum statistical theory of electron capture into many-electron compound resonances in highly charged ions

    CERN Document Server

    Berengut, J C; Dzuba, V A; Flambaum, V V; Gribakin, G F

    2015-01-01

    The strong mixing of many-electron basis states in excited atoms and ions with open $f$ shells results in very large numbers of complex, chaotic eigenstates that cannot be computed to any degree of accuracy. Describing the processes which involve such states requires the use of a statistical theory. Electron capture into these 'compound resonances' leads to electron-ion recombination rates that are orders of magnitude greater than those of direct, radiative recombination, and cannot be described by standard theories of dielectronic recombination. Previous statistical theories considered this as a two-electron capture process which populates a pair of single-particle orbitals, followed by 'spreading' of the two-electron states into chaotically mixed eigenstates. This method is similar to a configuration-average approach, as it neglects potentially important effects of spectator electrons and conservation of total angular momentum. In this work we develop a statistical theory which considers electron capture in...

  8. EVOLUTION OF IONS AFTER MULTIPLE ELECTRON-CAPTURE FROM SURFACES

    NARCIS (Netherlands)

    MORGENSTERN, R; DAS, J

    1993-01-01

    A comparison is made of the electronic processes which occur when a multiply charged ion is approaching an atomic target on the one hand or a metal surface on the other hand. In both caws three collision phases can be identified: those of attraction, of electron capture and of decay in the vacuum; i

  9. Capture rate and neutron helicity asymmetry for ordinary muon capture on hydrogen

    CERN Document Server

    Ando, S; Kubodera, K; Ando, Shung-ichi; Myhrer, Fred; Kubodera, Kuniharu

    2001-01-01

    Applying heavy-baryon chiral perturbation theory to ordinary muon capture (OMC) on a proton, we calculate the capture rate and neutron helicity asymmetry up to next-to-next-to-leading order. For the singlet hyperfine state, we obtain the capture rate Gamma_0 = 695 sec^{-1} while, for the triplet hyperfine state, we obtain the capture rate Gamma_1 = 11.9 sec^{-1} and the neutron asymmetry alpha_1 = 0.93. If the existing formalism is used to relate these atomic capture rate to Gamma_{liq}, the OMC rate in liquid hydrogen, then Gamma_{liq} corresponding to our improved values of Gamma_0 and Gamma_1 is found to be significantly larger than the experimental value. We argue that this apparent difficulity may be correlated to the specious anomaly recently reported for mu^- + p to n + nu_mu + gamma, and we suggest a possibility to remove these two "problems" simply and simultaneously by reexamining the molecular physics input that underlies the conventional analysis of Gamma_{liq}.

  10. The Sensitivity of Core-Collapse Supernovae to Nuclear Electron Capture

    CERN Document Server

    Sullivan, Chris; Zegers, Remco G T; Grubb, Thomas; Austin, Sam M

    2015-01-01

    A weak-rate library aimed at investigating the sensitivity of astrophysical environments to variations of electron-capture rates on medium-heavy nuclei has been developed. With this library, the sensitivity of the core-collapse and early post-bounce phases of core-collapse supernovae to nuclear electron-capture is examined by systematically and statistically varying electron-capture rates of individual nuclei. The rates are adjusted by factors consistent with uncertainties indicated by comparing theoretical rates to those deduced from charge-exchange and $\\beta$-decay measurements. To ensure a model independent assessment, sensitivity studies across a comprehensive set of progenitors and equations of state are performed. In our systematic study, we find a +16/-4 % range in the mass of the inner-core at the time of shock formation and a $\\pm$20% range of peak {\

  11. Measurement of internal conversion electrons from Gd neutron capture

    Energy Technology Data Exchange (ETDEWEB)

    Kandlakunta, P. [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States); Cao, L.R., E-mail: cao.152@osu.edu [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States); Mulligan, P. [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States)

    2013-03-21

    Gadolinium (Gd) is a suitable material for neutron conversion because of its superior neutron absorption cross-section. However, the principal secondary particles that generate electron-hole pairs in a semiconductor detector after Gd neutron capture are low-energy internal conversion (IC) electrons. We measured the IC electron spectrum due to Gd neutron capture by using a thermal neutron beam and a digitizer-based multidetector spectroscopy. We also discussed the effective use of the IC electrons in the context of a twin-detector design and the associated gamma-ray rejection issues. Extensive simulations of the spectra of IC electrons and gamma rays agreed well with the experimental results; both types of results support the feasibility of the proposed n–γ separation method.

  12. Searching of Double Electron Capture in the TGV Experiment

    CERN Document Server

    Brudanin, V B; Briançon, C; Benes, P; Vylov, T D; Gusev, K N; Egorov, V G; Klimenko, A A; Kovalenko, V E; Korolev, N A; Salamatin, A V; Timkov, V V; Cermák, P; Shirchenko, M V; Shitov, Yu A; Stekl, I

    2004-01-01

    The first investigations of the rare nuclear process - double electron capture of $^{106}$Cd have been performed using the low-background multi-detector spectrometer TGV-2 (Telescope Germanium Vertical). The preliminary results of calculations of experimental data obtained using 11.3 and 10 g of enriched $^{106}$Cd, and 14.5 g of natural Cd were presented. The sensitivity of T$_{1/2}^{EC/EC}>2.6\\cdot10^{19}$y (90\\% CL) was obtained for the searching of double electron capture of $^{106}$Cd ($0^{+} - 0^{+}$) in the investigation of natural Cd.

  13. Photons shedding light on electron capture by highly charged ions

    NARCIS (Netherlands)

    Hoekstra, Romke Anne

    1990-01-01

    In this thesis charge transfer is studied in collisions of highly charged ions (Aq+) with neutral particles (B). Because the electron is captured resonantly (i.e. without its binding energy) by the ion, a limited number of highly excited states (characterized by the quantum numbers nlm) is preferent

  14. ELECTRON-CAPTURE AND EXCITATION IN HE-2+-NA COLLISIONS

    NARCIS (Netherlands)

    SCHLATMANN, AR; HOEKSTRA, R; FOLKERTS, HO; MORGENSTERN, R

    1992-01-01

    State-selective charge transfer and target excitation in collisions of He2+ ions with Na has been studied by means of far ultraviolet and visible light spectroscopy. Generally, the experimental results confirm the theoretical predictions by Shingal, Noble and Bransden for electron capture and for

  15. Photons shedding light on electron capture by highly charged ions

    NARCIS (Netherlands)

    Hoekstra, Romke Anne

    1990-01-01

    In this thesis charge transfer is studied in collisions of highly charged ions (Aq+) with neutral particles (B). Because the electron is captured resonantly (i.e. without its binding energy) by the ion, a limited number of highly excited states (characterized by the quantum numbers nlm) is

  16. Calculation of Doublet Capture Rate for Muon Capture in Deuterium within Chiral Effective Field Theory

    CERN Document Server

    Adam, J; Tater, M; Truhlik, E; Epelbaum, E; Machleidt, R; Ricci, P

    2011-01-01

    The doublet capture rate of the negative muon capture in deuterium is calculated employing the nuclear wave functions generated from accurate nucleon-nucleon potentials constructed at next-to-next-to-next-to-leading order of heavy-baryon chiral perturbation theory and the weak meson exchange current operator derived within the same formalism. All but one of the low-energy constants that enter the calculation were fixed from pion-nucleon and nucleon-nucleon scattering data. The low-energy constant d^R (c_D), which cannot be determined from the purely two-nucleon data, was extracted recently from the triton beta-decay and the binding energies of the three-nucleon systems. The calculated values of the doublet capture rates show a rather large spread for the used values of the d^R. Precise measurement of the doublet capture rate in the future will not only help to constrain the value of d^R, but also provide a highly nontrivial test of the nuclear chiral EFT framework. Besides, the precise knowledge of the consta...

  17. Electron Capture by Tetra- and di-Chlorobenzene Molecules

    DEFF Research Database (Denmark)

    Pedersen, Niels Jørgen; Anisimov, O. A.; Lozouy, V. V.;

    1985-01-01

    ), their lifetimes being longer than roughly 10 ps and shorter than 10–30 ns. The cross section of electron capture by p-C6H4Cl2 in squalane is nearly one-tenth of that by 1,2,4,5-C6H2Cl4 and CCl4 at concentration ⩽ 0.02 M, while 10% of the electrons cannot be trapped even at 0.25 M p-C6H4Cl2. Probably the electrons......Experiments on inhibition and anti-inhibition of Ps formation and also on optical detection of ESR spectra in squalene solutions with 1,2,4,5-C6H2Cl4 and p-C6H4Cl2 have demonstrated the presence of short-lived molecular radical-anions (products of the spur electron capture by additives...... in the high-electric-field (0.3–3 MV/cm) regions of the spurs cannot be effectively captured by p-C6H4Cl2, which is a shallow electron trap. Similar effects of the high electric fields of the charged spur series seem to influence the Ps formation appreciably, along with the other effects discussed in previous...

  18. A combined beta-beam and electron capture neutrino experiment

    CERN Document Server

    Bernabeu, J; Orme, C; Palomares-Ruiz, S; Pascoli, S

    2009-01-01

    The next generation of long baseline neutrino experiments will aim at determining the value of the unknown mixing angle, theta_{13}, the type of neutrino mass hierarchy and the presence of CP-violation in the lepton sector. Beta-beams and electron capture experiments have been studied as viable candidates for long baseline experiments. They use a very clean electron neutrino beam from the beta-decays or electron capture decays of boosted ions. In the present article we consider an hybrid setup which combines a beta-beam with an electron capture beam by using boosted Ytterbium ions. We study the sensitivity to the CP-violating phase delta and the theta_{13} angle, the CP-discovery potential and the reach to determine the type of neutrino mass hierarchy for this type of long baseline experiment. The analysis is performed for different neutrino beam energies and baselines. Finally, we also discuss how the results would change if a better knowledge of some of the assumed parameters was achieved by the time this e...

  19. Influence of Magnetic Field Decay on Electron Capture in Magnetars

    Indian Academy of Sciences (India)

    Jie Zhang

    2014-09-01

    The de-excited energy of electron capture (EC) induced by magnetic field decay may be a new source for heating magnetar crust, so we do a quantitative calculation on EC process near the outer crust and analyse their influence on persistent X-ray radiation of magnetars, adopting the experimental data or the results of theoretical model (including the large-scale shell model and quasi-particle random phase approximation).

  20. Dissociative electron capture by. pi. -allyliron tricarbonyl halide molecules

    Energy Technology Data Exchange (ETDEWEB)

    Nekrasov, Y.S.; Avakyan, N.P.; Khvostenko, V.I.; Kritskaya, I.I.; Maurodiev, V.K.; Mazunov, V.A.

    1985-12-20

    Result are given for a study of dissociative electron impact by complexes (I)-(III), C/sub 3/H/sub 5/Fe (CO)/sub 3/ /SUP X/ , where X - C1 (I), Br (II), and of -allyliron tricarbonyl halides upon dissociative electron capture. The mechanisms for the formation of C/sub 3/H/sub 5/Fe (CO)/sup -//sub 3/ anions in the gas phase and under electrochemical reduction conditions on a dropping mercury electrode were shown to differ. A predominant effect was proposed for solvation factors on the electrochemical reduction in the condensed phase.

  1. Multiple electron capture in close ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Schlachter, A.S.; Stearns, J.W.; Berkner, K.H.; Bernstein, E.M.; Clark, M.W.; DuBois, R.D.; Graham, W.G.; Morgan, T.J.; Mueller, D.W.; Stockli, M.P.; Tanis, J.A.; Woodland, W.T. (Lawrence Berkeley Lab., CA (USA); Western Michigan Univ., Kalamazoo, MI (USA); Pacific Northwest Lab., Richland, WA (USA); Queen' s Univ., Belfast, Northern Ireland (UK); Wesleyan Univ., Middletown, CT (USA); University of North Tex

    1989-07-24

    Collisions in which a fast highly charged ion passes within the orbit of K electron of a target gas atom are selected by emission of a K x-ray from the projectile or target. Measurement of the projectile charge state after the collision, in coincidence with the K x-ray, allows measurement of the charge-transfer probability during these close collisions. When the projectile velocity is approximately the same as that of target electrons, a large number of electrons can be transferred to the projectile in a single collision. The electron-capture probability is found to be a linear function of the number of vacancies in the projectile L shell for 47-MeV calcium ions in an Ar target. 18 refs., 9 figs.

  2. Radiative Capture of Twisted Electrons by Bare Ions

    CERN Document Server

    Matula, Oliver; Serbo, Valeriy G; Surzhykov, Andrey; Fritzsche, Stephan

    2014-01-01

    Recent advances in the production of twisted electron beams with a subnanometer spot size offer unique opportunities to explore the role of orbital angular momentum (OAM) in basic atomic processes. In the present work, we address one of these processes: radiative recombination of twisted electrons with bare ions. Based on the density matrix formalism and the non-relativistic Schr\\"odinger theory, analytical expressions are derived for the angular distribution and the linear polarization of photons emitted due to the capture of twisted electrons into the ground state of (hydrogen-like) ions. We show that these angular and polarization distributions are sensitive to both, the transverse momentum and the topological charge of the electron beam. To observe in particular the value of this charge, we propose an experiment that makes use of the coherent superposition of two twisted beams.

  3. Is solar neutrino capture rate correlated with sunspot number?

    Science.gov (United States)

    Bahcall, J. N.; Field, G. B.; Press, W. H.

    1987-01-01

    The statistical significance of the apparent correlation between sunspots and the observed neutrino rate is quantified. It is shown that the correlation depends almost entirely upon four low neutrino capture rates near the beginning of 1980. A calculation based on standard electroweak theory and neutrino production processes demonstrates that a correlation, if real, would be extremely puzzling on energetic grounds alone. It is concluded that measurements with the Cl-37 detector during the next sunspot cycle will be needed to show that there is a physical correlation, since the existing data are not statistically significant at a definitive level.

  4. Hyperine transitions rates and capture rates in muonic F, Na, and Cl

    Energy Technology Data Exchange (ETDEWEB)

    Gorringe, T.P.; Johnson, B. Bauer, J. [and others

    1993-04-01

    From the time spectrum of {gamma}-rays following muon capture the authors have measured hyperfine transitions rates on muonic F, Na, and Cl, and the hyperfine dependence of the reaction {mu}{sup {minus}} {sup 23}Na(3/2{sup +},0) {r_arrow} {nu}{sup 23}Ne({1/2}{sup +},1017). They obtained hyperfine transition rates of 4.9{+-}1.2 {mu}s{sup {minus}1}, 8.4{+-}1.9 {mu}s{sup {minus}1}, and 6.5{+-}0.9 {mu}s{sup {minus}1}, for muonic F, Na, and Cl, respectively. The pattern of rates is in agreement with the calculations of Winston which indicate a general increase in rate with atomic number but a decrease at Cl where the emission of L shell electrons becomes forbidden. However, the authors` measured rates are systematically lower than the calculations of Winston (by 15 to 40 %), perhaps due to incomplete refilling of the muonic atom`s electron shells after formation. The hyperfine dependence of the reaction {mu}{sup {minus}} {sup 23}Na (3/2{sup +},0) {r_arrow} {nu} {sup 23}Ne({1/2}{sup +},1017) is dependent on the weak pseudoscalar coupling (g{sub p}) of the proton, and in an initial measurement at the TRIUMF laboratory gave a hyperfine dependence, {Lambda}{sub +}/{Lambda}{sub {minus}} = 0.18 {+-} 0.10, and a weak pseudoscalar coupling 5 {le} g{sub p}/g{sub e} {le} 15. A more recent measurement will determine g{sub p} to about 10 %, and will probe modifications of the coupling in the nuclear medium.

  5. Theory and Application of Dissociative Electron Capture in Molecular Identification

    CERN Document Server

    Havey, C D; Jones, T; Voorhees, K J; Laramee, J A; Cody, R B; Clougherty, D P; Eberhart, Mark; Voorhees, Kent J.; Laramee, James A.; Cody, Robert B.; Clougherty, Dennis P.

    2006-01-01

    The coupling of an electron monochromator (EM) to a mass spectrometer (MS) has created a new analytical technique, EM-MS, for the investigation of electrophilic compounds. This method provides a powerful tool for molecular identification of compounds contained in complex matrices, such as environmental samples. EM-MS expands the application and selectivity of traditional MS through the inclusion of a new dimension in the space of molecular characteristics--the electron resonance energy spectrum. However, before this tool can realize its full potential, it will be necessary to create a library of resonance energy scans from standards of the molecules for which EM-MS offers a practical means of detection. Here, an approach supplementing direct measurement with chemical inference and quantum scattering theory is presented to demonstrate the feasibility of directly calculating resonance energy spectra. This approach makes use of the symmetry of the transition-matrix element of the captured electron to discriminat...

  6. Electron capture by bare ions on water molecules

    Science.gov (United States)

    Rivarola, Roberto; Montenegro, Pablo; Monti, Juan; Fojón, Omar

    2016-05-01

    Single electron capture from water molecules by impact of bare ions is theoretically investigated at intermediate and high collision energies. This reaction is of fundamental importance to determine the deposition of energy in biological matter irradiated with ion beams (hadrontherapy), dominating other ionizing processes of the target at low-intermediate impact velocities and giving principal contributions to the energetic region where electronic stopping power maximizes. The dynamics of the interaction between the aggregates is described within the one active-electron continuum distorted wave-eikonal initial state theory. The orbitals of the target in the ground state are represented using the approximate self-consistent complete neglect of differential orbitals (SC-CNDO) model. The contribution of different molecular orbitals on the partial cross sections to selected n-principal quantum number projectile states is discriminated as well as the collaboration of these n-states on total cross sections. The latter ones are dominated by capture to n=1 states at high enough energies decreasing their contribution as n increases.

  7. Theory of nuclear excitation by electron capture for heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Gagyi-Palffy, A.

    2006-07-01

    The resonant process of nuclear excitation by electron capture (NEEC) in collisions involving highly-charged ions has been investigated theoretically. NEEC is a rare recombination process in which a free electron is captured into a bound shell of an ion with the simultaneous excitation of the nucleus. Total cross sections for NEEC followed by the radiative decay of the excited nucleus are presented for various collision systems. The possibility to observe the NEEC in scattering experiments with trapped or stored ions was discussed focusing on the cases with the largest calculated resonance strength. As the photons emitted in different channels of the electron recombination process are indistinguishable in the total cross section, the interference between NEEC followed by the radiative decay of the nucleus and radiative recombination was investigated. The angular distribution of the emitted photons in the recombination process provides means to discern the two processes. Angular differential cross sections for the emitted photons in the case of E2 nuclear transitions were presented for several heavy elements. (orig.)

  8. Electron capture of nuclides 52,53,54,55,56Fe in magnetars

    Institute of Scientific and Technical Information of China (English)

    LIU Jing-Jing

    2013-01-01

    Based on the theory of relativity in superstrong magnetic fields (SMFs),we have carried out an estimation on electron capture (EC) rates of nuclides 52,53,54,55,56Fe in the SMFs in magnetars.The rates of change of electronic fraction (RCEF) in the EC process are also discussed.The results show that the EC rates increase greatly and even exceeds by 4 orders of magnitude (e.g.54Fe,55Fe and 56Fe) in SMF.On the contrary,the RCEF decreases largely and even exceeds by 5 orders of magnitude in the SMF.

  9. Electron capture dissociation of singly and multiply phosphorylated peptides

    DEFF Research Database (Denmark)

    Stensballe, A; Jensen, Ole Nørregaard; Olsen, J V

    2000-01-01

    Analysis of phosphotyrosine and phosphoserine containing peptides by nano-electrospray Fourier transform ion cyclotron resonance (FTICR) mass spectrometry established electron capture dissociation (ECD) as a viable method for phosphopeptide sequencing. In general, ECD spectra of synthetic...... and native phosphopeptides appeared less complex than conventional collision activated dissociation (CAD) mass spectra of these species. ECD of multiply protonated phosphopeptide ions generated mainly c- and z(.)-type peptide fragment ion series. No loss of water, phosphate groups or phosphoric acid from......(III)-affinity chromatography combined with nano-electrospray FTMS/ECD facilitated phosphopeptide analysis and amino acid sequencing from crude proteolytic peptide mixtures....

  10. Electron Capture Dissociation of Weakly Bound Polypeptide Polycationic Complexes

    DEFF Research Database (Denmark)

    Haselmann, Kim F; Jørgensen, Thomas J D; Budnik, Bogdan A;

    2002-01-01

    We have previously reported that, in electron capture dissociation (ECD), rupture of strong intramolecular bonds in weakly bound supramolecular aggregates can proceed without dissociation of weak intermolecular bonds. This is now illustrated on a series of non-specific peptide-peptide dimers...... as well as specific complexes of modified glycopeptide antibiotics with their target peptide. The weak nature of bonding is substantiated by blackbody infrared dissociation, low-energy collisional excitation and force-field simulations. The results are consistent with a non-ergodic ECD cleavage mechanism....

  11. Testing the electron-capture supernova scenario using universal relations between neutron star properties

    Science.gov (United States)

    Newton, William

    2017-01-01

    8-10 solar mass stars may end their lives in electron-capture supernovae (ECSNe), in which ONeMg cores are destabilized by electron captures onto Neon and Magnesium. Strong circumstantial evidence exists that the Crab pulsar and PSR J0737-3039b were formed in ECSNe. Evidence for the existence of the ECSN mechanism has important implications for the rate of production of Be/X-ray binaries and the rate of binary neutron star mergers.I will discuss how supernova modeling suggests that neutron stars formed via the electron-capture mechanism have a specific gravitational binding energy. Recently, universal relations between neutron star properties including their binding energy, moment of inertia, quadrupole moments and tidal polarizability have been carefully examined. I will show how these relations, coupled with measurements of the post-Newtonian parameters of the PSR J0737-3039 system and of the acceleration of the Crab supernova remnant, can provide evidence for or against the electron-capture supernova formation scenario.

  12. Calculation of doublet capture rate for muon capture in deuterium within chiral effective field theory

    Science.gov (United States)

    Adam, J.; Tater, M.; Truhlík, E.; Epelbaum, E.; Machleidt, R.; Ricci, P.

    2012-03-01

    The doublet capture rate Λ1 / 2 of the negative muon capture in deuterium is calculated employing the nuclear wave functions generated from accurate nucleon-nucleon (NN) potentials constructed at next-to-next-to-next-to-leading order of heavy-baryon chiral perturbation theory and the weak meson exchange current operator derived within the same formalism. All but one of the low-energy constants that enter the calculation were fixed from pion-nucleon and nucleon-nucleon scattering data. The low-energy constant dˆR (cD), which cannot be determined from the purely two-nucleon data, was extracted recently from the triton β-decay and the binding energies of the three-nucleon systems. The calculated values of Λ1 / 2 show a rather large spread for the used values of the dˆR. Precise measurement of Λ1 / 2 in the future will not only help to constrain the value of dˆR, but also provide a highly nontrivial test of the nuclear chiral EFT framework. Besides, the precise knowledge of the constant dˆR will allow for consistent calculations of other two-nucleon weak processes, such as proton-proton fusion and solar neutrino scattering on deuterons, which are important for astrophysics.

  13. Single electron capture in fast ion-atom collisions

    Science.gov (United States)

    Milojević, Nenad

    2014-12-01

    Single-electron capture cross sections in collisions between fast bare projectiles and heliumlike atomic systems are investigated by means of the four-body boundary-corrected first Born (CB1-4B) approximation. The prior and post transition amplitudes for single charge exchange encompassing symmetric and asymmetric collisions are derived in terms of twodimensional real integrals in the case of the prior form and five-dimensional quadratures for the post form. The dielectronic interaction V12 = 1/r12 = 1/|r1 - r2| explicitly appears in the complete perturbation potential Vf of the post transition probability amplitude T+if. An illustrative computation is performed involving state-selective and total single capture cross sections for the p - He (prior and post form) and He2+, Li3+Be4+B5+C6+ - He (prior form) collisions at intermediate and high impact energies. We have also studied differential cross sections in prior and post form for single electron transfer from helium by protons. The role of dynamic correlations is examined as a function of increased projectile energy. Detailed comparisons with the measurements are carried out and the obtained theoretical cross sections are in reasonable agreement with the available experimental data.

  14. Two-dimensional electron-hole capture in a disordered hopping system

    Science.gov (United States)

    Greenham, N. C.; Bobbert, P. A.

    2003-12-01

    We model the two-dimensional recombination of electrons and holes in a system where the mean free path is short compared with the thermal capture radius. This recombination mechanism is relevant to the operation of bilayer organic light-emitting diodes (LED’s), where electrons and holes accumulate on either side of the internal heterojunction. The electron-hole recombination rate can be limited by the time taken for these charge carriers to drift and diffuse to positions where electrons and holes are directly opposite to each other on either side of the interface, at which point rapid formation of an emissive neutral state can occur. In this paper, we use analytical and numerical techniques to find the rate of this two-dimensional electron-hole capture process. Where one species of carrier is significantly less mobile than the other, we find that the recombination rate depends superlinearly on the density of the less mobile carrier. Numerical simulations allow the effects of disorder to be taken into account in a microscopic hopping model. Direct solution of the master equation for hopping provides more efficient solutions than Monte Carlo simulations. The rate constants extracted from our model are consistent with efficient emission from bilayer LED’s without requiring independent hopping of electrons and holes over the internal barrier at the heterojunction.

  15. Implementation of electronic data capture systems: barriers and solutions.

    Science.gov (United States)

    Welker, James A

    2007-05-01

    Although increasing in pace, the conversion to Electronic Data Capture (EDC) has been a slow progression. The use of EDC systems should confer improved data integrity, cost savings and a shorter time to study database closure. This will reduce the time to market and cost of new medications. With the current sentiment of the industry suggesting the cost analysis has been accepted to be in favor of EDC, the likely limitation to disseminated use is an inability to implement these systems. If the leadership at the sponsor, clinical research organization and investigator site is cognizant of the barriers to implementation, they can anticipate and mitigate them prior to the users becoming disgruntled and resistant to the new method of data capture. Once understood, barriers such as user input, technical support, user motivation, regulatory requirements, communication with users, timing of implementation, software installation, graphical user interface, identification of bridgers, patient participation, availability of technology, and costs can be better addressed at the beginning of the implementation process and successfully averted. This review discusses these barriers and potential solutions that can assist the clinical trial industry in achieving more wide-spread EDC use and the resulting improvement in operating efficiencies.

  16. Mutual neutralization in H+ - H- collisions by electron capture

    Science.gov (United States)

    Mančev, Ivan; Milojević, Nenad; Belkić, Dževad

    2013-07-01

    State-selective and total cross-sections for single-electron capture from H- by H+ covering the incident energy range from 10 to 3000 keV are computed by means of the four-body boundary corrected first Born (CB1-4B) approximation. A crucial connection between the Coulomb-distorted asymptotic state in the entrance channel and the pertinent perturbation, which causes the transition in the H+ - H- collisions, is consistently used in our computations of the “prior” version of cross-sections. The obtained results from the CB1-4B method clearly outperform the earlier findings by the close-coupling methods for the same problem. Comparisons with the available measurements are carried out and excellent agreement with the CB1 method is recorded down to impact energies as low as 10 keV.

  17. Neutrino energy loss by electron capture in magnetic field at the crusts of neutron stars

    Institute of Scientific and Technical Information of China (English)

    LIU Jing-Jing; LUO Zhi-Quan

    2008-01-01

    Based on the p-f shell model,the effect of strong magnetic field on neutrino energy loss rates by electron capture is investigated.The calculations show that the magnetic field has only a slight effect on the neutrino energy loss rates in the range of 108-1013 G on the surfaces of most neutron stars.But for some magnetars,the range of the magnetic field is 1013-1018 G,and the neutrino energy loss rates are greatly reduced,even by more than four orders of magnitude due to the strong magnetic field.

  18. Neutrino energy loss rates and positron capture rates on $^{55}$Co for presupernova and supernova physics

    CERN Document Server

    Nabi, Jameel-Un; 10.1103/PhysRevC.77.055802

    2011-01-01

    Proton-neutron quasi-particle random phase approximation (pn-QRPA) theory has recently being used for calculation of stellar weak interaction rates of $fp$-shell nuclide with success. Neutrino losses from proto-neutron stars play a pivotal role to decide if these stars would be crushed into black holes or explode as supernovae. The product of abundance and positron capture rates on $^{55}$Co is substantial and as such can play a role in fine tuning of input parameters of simulation codes specially in the presupernova evolution. Recently we introduced our calculation of capture rates on $^{55}$Co, in a luxurious model space of $7 \\hbar \\omega$, employing the pn-QRPA theory with a separable interaction. Simulators, however, may require these rates on a fine scale. Here we present for the first time an expanded calculation of the neutrino energy loss rates and positron capture rates on $^{55}$Co on an extensive temperature-density scale. These type of scale is appropriate for interpolation purposes and of greate...

  19. Electron correlations in single-electron capture from helium by fast protons and α particles

    Science.gov (United States)

    Mančev, Ivan; Milojević, Nenad

    2010-02-01

    Single-electron capture from heliumlike atomic systems by bare projectiles is investigated by means of the four-body boundary-corrected first Born approximation (CB1-4B). The effect of the dynamic electron correlation is explicitly taken into account through the complete perturbation potential. The quantum-mechanical post and prior transition amplitudes for single charge exchange encompassing symmetric and/or asymmetric collisions are derived in terms of two-dimensional real integrals in the case of the prior form and five-dimensional quadratures for the post form. An illustrative computation is performed for single-electron capture from helium by protons and α particles at intermediate and high impact energies. The role of dynamic correlations is examined as a function of increased projectile energy. The validity and utility of the proposed CB1-4B method is critically assessed in comparison with the existing experimental data for total cross sections, and excellent agreement is obtained.

  20. State Space Path Integrals for Electronically Nonadiabatic Reaction Rates

    CERN Document Server

    Duke, Jessica Ryan

    2016-01-01

    We present a state-space-based path integral method to calculate the rate of electron transfer (ET) in multi-state, multi-electron condensed-phase processes. We employ an exact path integral in discrete electronic states and continuous Cartesian nuclear variables to obtain a transition state theory (TST) estimate to the rate. A dynamic recrossing correction to the TST rate is then obtained from real-time dynamics simulations using mean field ring polymer molecular dynamics. We employ two different reaction coordinates in our simulations and show that, despite the use of mean field dynamics, the use of an accurate dividing surface to compute TST rates allows us to achieve remarkable agreement with Fermi's golden rule rates for nonadiabatic ET in the normal regime of Marcus theory. Further, we show that using a reaction coordinate based on electronic state populations allows us to capture the turnover in rates for ET in the Marcus inverted regime.

  1. Geometry dependence of Auger carrier capture rates into cone-shaped self-assembled quantum dots

    DEFF Research Database (Denmark)

    Magnúsdóttir, Ingibjörg; Bischoff, Svend; Uskov, A.V.;

    2003-01-01

    We calculate carrier capture rates into cone- and truncated-cone-shaped quantum dots mediated by Auger processes. It is demonstrated that the capture rates depend strongly on both dot size and shape. The importance of phonon-mediated versus the Auger-mediated capture processes is discussed....

  2. Midwife to the greens: the electron capture detector.

    Science.gov (United States)

    Lovelock, J E

    1997-03-01

    James E. Lovelock makes an account of the path he has followed since he started his scientific research at the National Institute for Medical Research (NIMR) in London in the 1940s, emphasizing the aspects related to environmental sciences. Lovelock explains the origins of the electron capture detector (ECD). So far, the ECD is the most sensitive, easily portable and inexpensive analytical apparatus capable of detecting substances present in the atmosphere at concentrations as low as parts per trillion (10(-12)). It has been the first device specifically sensitive to pollutants, and its use has provided the grounds for the development of environmental sciences, and green politics. The data gathered by the ECD about the persistence of pesticides in the environment led American biologist Rachel Carson to write her seminal book Silent Spring; data regarding the global presence of chlorofluorocarbons (CFC) in the atmosphere led Sherwood Rowland and Mario Molina to develop their theory of ozone depletion. The results of his research over the years led Lovelock himself to the development of the Gaia theory.

  3. ELECTRON-CAPTURE SUPERNOVAE AS SOURCES OF {sup 60}Fe

    Energy Technology Data Exchange (ETDEWEB)

    Wanajo, Shinya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Janka, Hans-Thomas; Mueller, Bernhard, E-mail: shinya.wanajo@nao.ac.jp [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)

    2013-09-01

    We investigate the nucleosynthesis of the radionuclide {sup 60}Fe in electron-capture supernovae (ECSNe). The nucleosynthetic results are based on a self-consistent, two-dimensional simulation of an ECSN as well as models in which the densities are systematically increased by some factors (low-entropy models). {sup 60}Fe is found to be appreciably made in neutron-rich ejecta during the nuclear quasi-equilibrium phase with greater amounts being produced in the lower-entropy models. Our results, combining them with the yields of core-collapse supernovae in the literature, suggest that ECSNe account for at least 4%-30% of live {sup 60}Fe in the Milky Way. ECSNe co-produce neutron-rich isotopes, {sup 48}Ca, {sup 50}Ti, {sup 54}Cr, some light trans-iron elements, and possibly weak r-process elements including some radionuclides such as {sup 93}Zr, {sup 99}Tc, and {sup 107}Pd, whose association with {sup 60}Fe might have been imprinted in primitive meteorites or in the deep ocean crust on the Earth.

  4. Validation of undergraduate clinical data by electronic capture (barcode).

    Science.gov (United States)

    Chadwick, Barbara L; Oliver, Richard G; Gyton, Jane

    2002-03-01

    Assessment of clinical activity is common in dental schools. An audit project to confirm that dental undergraduate clinical activity recorded by electronic data capture is an accurate representation of the clinical case entry is reported. A printout of clinical activity for a period of a week was generated retrospectively and used to identify case notes. Activity recorded in the case notes was compared with the computer printout. All discrepancies were noted. A total of 125 patient files with 270 barcoded items of treatment were retrieved; 29 of 78 (37.1%) paediatric and 23 of 47 (48.9%) orthodontic cases had discrepancies between the case notes and the computer entry. However, some items recorded in the notes do not require barcoding and vice versa. When these were accounted for, only 19 items of treatment appeared in the notes that should have been barcoded, a 7% shortfall in recording of clinical activity. The barcode system is an accurate and reliable way of recording undergraduate clinical activity.

  5. Improving the Electronic Capture of Advance Care Directives in a Healthcare Delivery System.

    Science.gov (United States)

    Kamo, Norifumi; Williams, Barbara L; Smith, Donna L; Blackmore, C Craig

    2017-05-01

    To determine the effectiveness of a multifaceted quality improvement intervention in outpatient clinics at an integrated healthcare delivery system on capture rate of advance directives (ADs) in the electronic medical record (EMR). Interrupted time series analysis with control groups between January 2010 and June 2015. Oncology, nephrology, and primary care outpatient clinics in an integrated healthcare delivery system. All individuals aged 65 and older with at least one office visit in any outpatient clinic in the care delivery system (n = 77,350 with 502,446 office visits). A series of quality improvement interventions to improve rates of advance care planning discussions and capture of those discussions in the EMR between 2010 and 2014. Capture rate of ADs in the EMR. Visits in the intervention primary care clinic were twice as likely to mention ADs in the EMR (53.4%) than visits in nonintervention primary care clinics (26.5%). Visits in the intervention oncology clinic were more than eight times as likely to mention ADs in the EMR (49.3% vs 6.0%), and visits in the intervention nephrology clinic were 2.5 times as likely to mention ADs (15.4% vs 6.0%) than visits in other specialty clinics. A series of quality improvement interventions to increase discussions about advance care planning and capture of advance care directives in the EMR significantly increased the rate of capture in primary care and specialty care outpatient settings. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

  6. Parametric control of collision rates and capture rates in geometrically enhanced differential immunocapture (GEDI) microfluidic devices for rare cell capture.

    Science.gov (United States)

    Smith, James P; Lannin, Timothy B; Syed, Yusef; Santana, Steven M; Kirby, Brian J

    2014-02-01

    The enrichment and isolation of rare cells from complex samples, such as circulating tumor cells (CTCs) from whole blood, is an important engineering problem with widespread clinical applications. One approach uses a microfluidic obstacle array with an antibody surface functionalization to both guide cells into contact with the capture surface and to facilitate adhesion; geometrically enhanced differential immunocapture is a design strategy in which the array is designed to promote target cell–obstacle contact and minimize other interactions (Gleghorn et al. 2010; Kirby et al. 2012). We present a simulation that uses capture experiments in a simple Hele-Shaw geometry (Santana et al. 2012) to inform a target-cell-specific capture model that can predict capture probability in immunocapture microdevices of any arbitrary complex geometry. We show that capture performance is strongly dependent on the array geometry, and that it is possible to select an obstacle array geometry that maximizes capture efficiency (by creating combinations of frequent target cell–obstacle collisions and shear stress low enough to support capture), while simultaneously enhancing purity by minimizing nonspecific adhesion of both smaller contaminant cells (with infrequent cell–obstacle collisions) and larger contaminant cells (by focusing those collisions into regions of high shear stress).

  7. Warm Dark Matter Sterile Neutrinos in Electron Capture and Beta Decay Spectra

    Directory of Open Access Journals (Sweden)

    O. Moreno

    2016-01-01

    Full Text Available We briefly review the motivation to search for sterile neutrinos in the keV mass scale, as dark matter candidates, and the prospects to find them in beta decay or electron capture spectra, with a global perspective. We describe the fundamentals of the neutrino flavor-mass eigenstate mismatch that opens the possibility of detecting sterile neutrinos in such ordinary nuclear processes. Results are shown and discussed for the effect of heavy neutrino emission in electron capture in Holmium 163 and in two isotopes of Lead, 202 and 205, as well as in the beta decay of Tritium. We study the deexcitation spectrum in the considered cases of electron capture and the charged lepton spectrum in the case of Tritium beta decay. For each of these cases, we define ratios of integrated transition rates over different regions of the spectrum under study and give new results that may guide and facilitate the analysis of possible future measurements, paying particular attention to forbidden transitions in Lead isotopes.

  8. Neutrino energy loss by electron capture on strongly screened iron group nuclei

    Institute of Scientific and Technical Information of China (English)

    Liu Jing-Jing; Luo Zhi-Quan

    2007-01-01

    The influences on the neutrino energy loss rates in iron group nuclei at the same density are investigated in the presence of strong electron screening and in the absence of electron screening. The results show that at a temperature of 15 × 109 K, the neutrino energy loss rates which come from the electron capture processfor most iron group nuclei decrease no more than 2 orders of magnitude but for the others (such as 53,55,56,57,58,59,60Co, 56,59Ni) they can decrease about 3 orders of magnitude due to strong electron screening (SES), whereas, at a temperature of 109K the neutrino energy loss rates of the most iron group nuclei can be diminished greatly due to the SES. For example, 61Fe, 60Fe,and 62Ni the neutrino energy loss rates decrease about 4, 15 and 16 orders of magnitude and for 57Cr, 58Cr, and 60Cr decrease about 18, 12, and 10 orders of magnitude respectively. According to our calculations the neutrino energy loss rates of nuclei 58Mn, 59Mn, 60Mn, and 62Mn may decrease about 13 orders of magnitude at a temperature of 109 K due to the SES.

  9. HE-2+-H2 COLLISIONS - NONDISSOCIATIVE AND DISSOCIATIVE ONE-ELECTRON CAPTURE

    NARCIS (Netherlands)

    HOEKSTRA, R; FOLKERTS, HO; BEIJERS, JPM; MORGENSTERN, R; DEHEER, FJ

    1994-01-01

    Electron-redistribution processes in collisions of He-2+ ions on H-2 are studied for energies from 1 to 25 keV amu-1. One-electron capture and target excitation cross sections are determined by photon-emission spectroscopy. At energies exceeding approximately 5 keV amu-1 capture into excited states

  10. Determination of the Electron Neutrino Mass from Experiments on Electron-Capture Beta-Decay (EC)

    CERN Multimedia

    2002-01-01

    The aim of the programme is to measure the electron-neutrino mass, for which at present an upper limit of 500~eV is known. \\\\ \\\\ The experiment studies the shape of the internal bremsstrahlung spectrum in electron-capture near its upper end-point and deduces a mass from small shape changes completely analogous to those in the well-known determination of the electron antineutrino mass in the tritium beta-minus decay. \\\\ \\\\ In a low-energy bremsstrahlung process, the capture takes place from a virtual S state associated with a radiative P~@A~S electromagnetic transition, and the resonant nature of the process leads to important enhancements of the photon intensities at low energy, in particular near the resonance energies co (X-rays). This effect gives this type of experiment a chance to compete with experiments on continuous beta spectra. \\\\ \\\\ The programme concentrates on two long-lived isotopes: \\\\ \\\\ 1)~~|1|6|3Ho. The Q value for this isotope has been found to be 2.6-2.7 keV. A detector specially construct...

  11. Entertainment Capture through Heart Rate Activity in Physical Interactive Playgrounds

    DEFF Research Database (Denmark)

    Yannakakis, Georgios; Hallam, John; Lund, Henrik Hautop

    2008-01-01

    that predict reported entertainment preferences given HR features. These models are expressed as artificial neural networks and are demonstrated and evaluated on two Playware games and two control tasks requiring physical activity. The best network is able to correctly match expressed preferences in 64......An approach for capturing and modeling individual entertainment (“fun”) preferences is applied to users of the innovative Playware playground, an interactive physical playground inspired by computer games, in this study. The goal is to construct, using representative statistics computed from...

  12. Correlated double electron capture in slow, highly charged ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Stolterfoht, N.; Havener, C.C.; Phaneuf, R.A.; Swenson, J.K.; Shafroth, S.M.; Meyer, F.W.

    1986-01-01

    Recent measurements of autoionization electrons produced in slow, highly charged ion-atom collisions are reviewed. Mechanisms for double electron capture into equivalent and nonequivalent configurations are analyzed by comparing the probabilities for the creation of L/sub 1/L/sub 23/X Coster Kronig electrons and L-Auger electrons. It is shown that the production of the Coster-Kronig electrons is due to electron correlation effects whose analysis leads beyond the independent-particle model. The importance of correlation effects on different capture mechanisms is discussed. 28 refs., 6 figs.

  13. Ionization and single electron capture in collision of highly charged Ar16+ ions with helium

    Institute of Scientific and Technical Information of China (English)

    Wang Fei; Gou Bing-Cong

    2008-01-01

    This paper uses the two-centre atomic orbital close-coupling method to study the ionization and the single electron capture in collision of highly charged Ar16+ ions with He atoms in the velocity range of 1.2-1.9 a.u.. The relative importance of single ionization (SI) to single capture (SC) is explored. The comparison between the calculation and experimental data shows that the SI/SC cross section ratios from this work are in good agreement with experimental data. The total single electron ionization cross sections and the total single electron capture cross sections are also given for this collision. The investigation of the partial electron capture cross section shows a general tendency of capture to larger n and l with increasing velocity from 1.2 to 1.9 a.u..

  14. Stellar neutron capture rates and the s process

    Directory of Open Access Journals (Sweden)

    Käppeler F.

    2012-02-01

    Full Text Available Neutron reactions are responsible for the formation of the elements heavier than iron. The corresponding scenarios relate to helium burning in Red Giant stars (s process and to supernova explosions (r and p processes. The s process, which operates in or near the valley of β-stability, has produced about half of the elemental abundances between Fe and Bi. Accurate (n, γ cross sections are the essential input for s process studies, because they determine the abundances produced by that process. Following a brief summary of the neutron capture processes, the focus will be set on the s process in massive stars, where the role of reliable cross section information is particularly important. Eventually, the intriguing aspects of the origin of 60Fe will be addressed. Attempts to determine the stellar cross section of that isotope are pushing experimental possibilities to their limits and present a pertinent challenge for future facilities.

  15. Electron dose rate and photon contamination in electron arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Pla, M.; Podgorsak, E.B.; Pla, C. (McGill Univ., Montreal, Quebec (Canada))

    1989-09-01

    The electron dose rate at the depth of dose maximum dmax and the photon contamination are discussed as a function of several parameters of the rotational electron beam. A pseudoarc technique with an angular increment of 10 degrees and a constant number of monitor units per each stationary electron field was used in our experiments. The electron dose rate is defined as the electron dose at a given point in phantom divided by the number of monitor units given for any one stationary electron beam. For a given depth of isocenter di the electron dose rates at dmax are linearly dependent on the nominal field width w, while for a given w the dose rates are inversely proportional to di. The dose rates for rotational electron beams with different di are related through the inverse square law provided that the two beams have (di,w) combinations which give the same characteristic angle beta. The photon dose at the isocenter depends on the arc angle alpha, field width w, and isocenter depth di. For constant w and di the photon dose at isocenter is proportional to alpha, for constant alpha and w it is proportional to di, and for constant alpha and di it is inversely proportional to w. The w and di dependence implies that for the same alpha the photon dose at the isocenter is inversely proportional to the electron dose rate at dmax.

  16. Limit on the radiative neutrinoless double electron capture of ^{36}Ar from GERDA Phase I

    Science.gov (United States)

    Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barros, N.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2016-12-01

    Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of ^{36}Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array ( Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of ^{36}Ar was established: T_{1/2} > 3.6 × 10^{21} years at 90% CI.

  17. Limit on the radiative neutrinoless double electron capture of {sup 36}Ar from GERDA Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Agostini, M.; Balata, M.; D' Andrea, V.; Di Vacri, A.; Junker, M.; Laubenstein, M. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); Allardt, M.; Domula, A.; Lehnert, B.; Schneider, B.; Wester, T.; Wilsenach, H.; Zuber, K. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); Bakalyarov, A.M.; Belyaev, S.T.; Lebedev, V.I.; Zhukov, S.V. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Barabanov, I.; Bezrukov, L.; Doroshkevich, E.; Fedorova, O.; Gurentsov, V.; Kazalov, V.; Kuzminov, V.V.; Lubsandorzhiev, B.; Moseev, P.; Selivanenko, O.; Veresnikova, A.; Yanovich, E. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Barros, N. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); University of Pennsylvania, Philadelphia, PA (United States); Baudis, L.; Benato, G.; Kish, A.; Miloradovic, M.; Mingazheva, R.; Walter, M. [Physik Institut der Universitaet Zuerich, Zurich (Switzerland); Bauer, C.; Hakenmueller, J.; Heisel, M.; Heusser, G.; Hofmann, W.; Kihm, T.; Kirsch, A.; Knoepfle, K.T.; Lindner, M.; Maneschg, W.; Salathe, M.; Schreiner, J.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Stepaniuk, M.; Wagner, V.; Wegmann, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Bellotti, E. [Universita Milano Bicocca, Dipartimento di Fisica, Milan (Italy); INFN Milano Bicocca, Milan (Italy); Belogurov, S.; Kornoukhov, V.N. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Institute for Theoretical and Experimental Physics NRC ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Bettini, A.; Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Sada, C.; Sturm, K. von [Dipartimento di Fisica e Astronomia dell' Universita di Padova, Padua (Italy); INFN Padova, Padua (Italy); Bode, T.; Csathy, J.J.; Lazzaro, A.; Schoenert, S.; Wiesinger, C. [Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Borowicz, D. [Jagiellonian University, Institute of Physics, Krakow (Poland); Joint Institute for Nuclear Research, Dubna (Russian Federation); Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Rumyantseva, N.; Zhitnikov, I.; Zinatulina, D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Caldwell, A.; Gooch, C.; Kneissl, R.; Liao, H.Y.; Majorovits, B.; Palioselitis, D.; Schulz, O.; Vanhoefer, L. [Max-Planck-Institut fuer Physik, Munich (Germany); Cattadori, C.; Salamida, F. [INFN Milano Bicocca, Milan (Italy); Chernogorov, A.; Demidova, E.V.; Kirpichnikov, I.V.; Vasenko, A.A. [Institute for Theoretical and Experimental Physics NRC ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Falkenstein, R.; Freund, K.; Grabmayr, P.; Hegai, A.; Jochum, J.; Schmitt, C.; Schuetz, A.K. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Frodyma, N.; Misiaszek, M.; Panas, K.; Pelczar, K.; Wojcik, M.; Zuzel, G. [Jagiellonian University, Institute of Physics, Krakow (Poland); Gangapshev, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Gusev, K. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Hemmer, S.; Lippi, I.; Stanco, L. [INFN Padova, Padua (Italy); Hult, M.; Lutter, G. [European Commission, JRC-Geel, Geel (Belgium); Inzhechik, L.V. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Moscow Institute of Physics and Technology, Moscow (Russian Federation); Klimenko, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); International University for Nature, Society and Man ' ' Dubna' ' , Dubna (Russian Federation); Lubashevskiy, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Macolino, C. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); LAL, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Pandola, L. [INFN Laboratori Nazionali del Sud, Catania (Italy); Pullia, A.; Riboldi, S. [Universita degli Studi di Milano, Dipartimento di Fisica, Milan (Italy); INFN Milano (Italy); Shirchenko, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Collaboration: GERDA collaboration

    2016-12-15

    Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of {sup 36}Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of {sup 36}Ar was established: T{sub 1/2} > 3.6 x 10{sup 21} years at 90% CI. (orig.)

  18. Limit on the Radiative Neutrinoless Double Electron Capture of $^{36}$Ar from GERDA Phase I

    CERN Document Server

    Agostini, M; Bakalyarov, A M; Balata, M; Barabanov, I; Barros, N; Baudis, L; Bauer, C; Bellotti, E; Belogurov, S; Belyaev, S T; Benato, G; Bettini, A; Bezrukov, L; Bode, T; Borowicz, D; Brudanin, V; Brugnera, R; Caldwell, A; Cattadori, C; Chernogorov, A; D'Andrea, V; Demidova, E V; di Vacri, A; Domula, A; Doroshkevich, E; Egorov, V; Falkenstein, R; Fedorova, O; Freund, K; Frodyma, N; Gangapshev, A; Garfagnini, A; Gooch, C; Grabmayr, P; Gurentsov, V; Gusev, K; Hakenmüller, J; Hegai, A; Heisel, M; Hemmer, S; Heusser, G; Hofmann, W; Hult, M; Inzhechik, L V; Csáthy, J Janicskó; Jochum, J; Junker, M; Kazalov, V; Kihm, T; Kirpichnikov, I V; Kirsch, A; Kish, A; Klimenko, A; Kneißl, R; Knöpfle, K T; Kochetov, O; Kornoukhov, V N; Kuzminov, V V; Laubenstein, M; Lazzaro, A; Lebedev, V I; Lehnert, B; Liao, H Y; Lindner, M; Lippi, I; Lubashevskiy, A; Lubsandorzhiev, B; Lutter, G; Macolino, C; Majorovits, B; Maneschg, W; Medinaceli, E; Miloradovic, M; Mingazheva, R; Misiaszek, M; Moseev, P; Nemchenok, I; Palioselitis, D; Panas, K; Pandola, L; Pelczar, K; Pullia, A; Riboldi, S; Rumyantseva, N; Sada, C; Salamida, F; Salathe, M; Schmitt, C; Schneider, B; Schönert, S; Schreiner, J; Schütz, A -K; Schulz, O; Schwingenheuer, B; Selivanenko, O; Shirchenko, M; Simgen, H; Smolnikov, A; Stanco, L; Stepaniuk, M; Vanhoefer, L; Vasenko, A A; Veresnikova, A; von Sturm, K; Wagner, V; Walter, M; Wegmann, A; Wester, T; Wiesinger, C; Wilsenach, H; Wojcik, M; Yanovich, E; Zhitnikov, I; Zhukov, S V; Zinatulina, D; Zuber, K; Zuzel, G

    2016-01-01

    Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of $^{36}$Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (GERDA) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of $^{36}$Ar was established: $T_{1/2} > $ 4.0 $\\times$ 10$^{21}$ yr at 90 % C.I.

  19. Ground and excited states Gamow-Teller strength distributions of iron isotopes and associated capture rates for core-collapse simulations

    Science.gov (United States)

    Nabi, Jameel-Un

    2011-02-01

    This paper reports on the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions, both in the electron capture and electron decay direction, for 54,55,56Fe. The associated electron and positron capture rates for these isotopes of iron are also calculated in stellar matter. These calculations were recently introduced and this paper is a follow-up which discusses in detail the GT strength distributions and stellar capture rates of key iron isotopes. The calculations are performed within the framework of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic state-by-state calculation of GT strength functions and stellar capture rates which greatly increases the reliability of the results. For the first time experimental deformation of nuclei are taken into account. In the core of massive stars isotopes of iron, 54,55,56Fe, are considered to be key players in decreasing the electron-to-baryon ratio ( Y e ) mainly via electron capture on these nuclide. The structure of the presupernova star is altered both by the changes in Y e and the entropy of the core material. Results are encouraging and are compared against measurements (where possible) and other calculations. The calculated electron capture rates are in overall good agreement with the shell model results. During the presupernova evolution of massive stars, from oxygen shell burning stages till around end of convective core silicon burning, the calculated electron capture rates on 54Fe are around three times bigger than the corresponding shell model rates. The calculated positron capture rates, however, are suppressed by two to five orders of magnitude.

  20. Gamow-Teller strength distributions at finite temperatures and electron capture in stellar environments

    CERN Document Server

    Dzhioev, Alan A; Ponomarev, V Yu; Wambach, J; Langanke, K; Martínez-Pinedo, G

    2009-01-01

    We propose a new method to calculate stellar weak-interaction rates. It is based on the Thermo-Field-Dynamics formalism and allows the calculation of the weak-interaction response of nuclei at finite temperatures. The thermal evolution of the GT$_+$ distributions is presented for the sample nuclei $^{54, 56}$Fe and ~$^{76,78,80}$Ge. For Ge we also calculate the strength distribution of first-forbidden transitions. We show that thermal effects shift the GT$_+$ centroid to lower excitation energies and make possible negative- and low-energy transitions. In our model we demonstrate that the unblocking effect for GT$_+$ transitions in neutron-rich nuclei is sensitive to increasing temperature. The results are used to calculate electron capture rates and are compared to those obtained from the shell model.

  1. Resonant antineutrino induced electron capture with low energy bound-beta beams

    CERN Document Server

    Oldeman, R G C; Saitta, B

    2009-01-01

    Antineutrino induced electron capture is a resonant process that can have a larg e cross-section for beams of monochromatic antineutrinos. We calculate the cross-section of this process and investigate an experimental setup where monochromatic antineutrinos are produced from the bound-beta decay of fully ionized radioactive atoms in a storage ring. If the energy between the source and the target is well matched, the cross-sections can be significantly larger than the cross-sections of commonly used non-resonant processes. The rate that can be achieved at a small distance between the source and two targets of $10^3$ kg is up to one interaction per $8 .3\\cdot10^{18}$ decaying atoms. For a source-target distance corresponding to the first atmospheric neutrino osc illation maximum, the largest rate is one interaction per $3.2\\cdot10^{21}$ decaying atoms.

  2. Measurements of Pair Production and Electron Capture from the Continuum in Heavy Particle Collisions

    CERN Multimedia

    2002-01-01

    Large transient Coulomb fields, which are generated in collisions of high-Z systems at sufficiently high energies, lead to copious production of electron-positron pairs. It has been suggested that these lepton pairs might mask signals arising from plasma phase interaction. Pair-production cross sections have been calculated by several authors with results which differ significantly from each other. Some of the electrons produced may be captured into bound states of the ion, thereby, reducing its charge state by one unit. This process which has been termed ``Electron Capture from Pair Production``, represents the only electron capture pro which increases with energy, and as such, will dominate all others in the ultrarelativistic energy regime. Ions having undergone this process would be lost from storage-type accelerators. The absolute cross sections for capture have been calculated with results which differ by as much as an order of magnitude. If as large as some of the calculations predict, Relativistic Heav...

  3. Electron capture dissociation proceeds with a low degree of intramolecular migration of peptide amide hydrogens

    DEFF Research Database (Denmark)

    Rand, Kasper D; Adams, Christopher M; Zubarev, Roman A;

    2008-01-01

    scrambling) that occurs during vibrational excitation of gas-phase ions. Unlike traditional collisional ion activation, electron capture dissociation (ECD) is not associated with substantial vibrational excitation. We investigated the extent of intramolecular backbone amide hydrogen (1H/2H) migration upon...... ECD using peptides with a unique selective deuterium incorporation. Our results show that only limited amide hydrogen migration occurs upon ECD, provided that vibrational excitation prior to the electron capture event is minimized. Peptide ions that are excessively vibrationally excited...

  4. The influence of flow velocity and food concentration on Lophelia pertusa (Scleractinia) zooplankton capture rates

    NARCIS (Netherlands)

    Purser, A.; Larsson, A.I.; Thomsen, L.; Van Oevelen, D.

    2010-01-01

    Lophelia pertusa is the most significant framework building scleractinian coral in European seas, yet the reproductive strategy, longevity, growth and food capture rates for the species remain poorly understood. In this study an experimental investigation into the ability of L. pertusa to capture zo

  5. Temporal patterns in capture rate and sex ratio of forest bats in Arkansas

    Science.gov (United States)

    Roger W. Perry; S. Andrew Carter; Ronald E. Thill

    2010-01-01

    We quantified changes in capture rates and sex ratios from May to Sept. for eight species of bats, derived from 8 y of extensive mist netting in forests of the Ouachita Mountains, Arkansas. Our primary goal was to determine patterns of relative abundance for each species of bat captured over forest streams and to determine if these patterns were similar to patterns of...

  6. Differential cross sections for single-electron capture in He{sup 2+}-D collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, D.; Dagnac, R. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)]|[Toulouse-3 Univ., 31 (France)

    1995-06-14

    A translational energy spectroscopy technique was used to study single-electron capture into the He{sup +} (n = 2) and He{sup +} (n 3) states in He{sup 2+}-D collisions. Differential cross sections were determined at 4, 6 and 8 keV in the angular range 5`-1{sup o}30` (laboratory frame). As expected, single-electron capture into the n = 2 state was found to be the dominant process; total cross sections for capture into the He{sup +} (n = 3) state were compared to other experimental and theoretical results. (author).

  7. Calculations of energies and absolute intensities of Auger electrons and X-rays arising from electron capture decay

    Institute of Scientific and Technical Information of China (English)

    ZHOU Chun-Mei; WU Zhen-Dong; HUANG Xiao-Long

    2005-01-01

    Calculations of energies and absolute intensities of Auger electron and X-ray arising from electron capture are introduced briefly. The calculation codes and main process are also presented. The application is also given by taking 55Fe ε decay as an example.

  8. Electron capture decay of {sup 116}In and nuclear structure of double {beta} decays

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, M.; Garcia, A.; Ortiz, C.E.; Kaloskamis, N.I. [University of Notre Dame, Notre Dame, Indiana 46556 (United States); Hindi, M.M. [Physics Department, Tennessee Technological University, Cookeville, Tennessee 38505 (United States); Norman, E.B. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Davids, C.N. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Civitarese, O. [Department of Physics, University of La Plata, C. C. 67, 1900-La Plata (Argentina); Suhonen, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, SF-40351, Jyvaeskylae (Finland)

    1998-08-01

    Quasiparticle-random-phase-approximation (QRPA) calculations of double {beta} decays have not been able to reproduce data in the A=100 system. We propose the A=116 system{emdash}because of its smaller deformation{emdash}as a simpler system to test QRPA calculations. We present results of two experiments we performed, which determine the electron-capture-decay branch of {sup 116}In to be (2.27{plus_minus}0.63){times}10{sup {minus}2}{percent}, from which we deduce logft=4.39{sub {minus}0.15}{sup +0.10}. We present QRPA calculations and compare their predictions to experimental data. Finally we use these calculations to predict the 2{nu} double-{beta}-decay rate of {sup 116}Cd to the ground and excited states of {sup 116}Sn. {copyright} {ital 1998} {ital The American Physical Society}

  9. STATE-SELECTIVE ELECTRON-CAPTURE IN HE2+ -H2 COLLISIONS

    NARCIS (Netherlands)

    MENG, L; OLSON, RE; FOLKERTS, HO; HOEKSTRA, R

    1994-01-01

    A classical phase-space model of the hydrogen molecule which includes both electrons and nuclear centers is utilized to study state selective electron capture for collisions with alpha particles at intermediate impact energies (30-200 keV amu-1). The calculations am performed within the framework of

  10. Electron Capture in 163Ho and Overlap plus Exchange Corrections and the Neutrino Mass

    CERN Document Server

    Faessler, Amand; Simkovic, M F

    2014-01-01

    Holmium offers perhaps the best chance to determine the neutrino mass by electron capture. This contribution treats the electron capture in 163Holmium completely relativistic for the overlap and exchange corrections. The theoretical expressions are derived consistently in second quantisation with the help of Wick's theorem assuming single Slater determinants for the initial Ho and the final Dy atoms with holes in the final ns1/2 and np1/2 states. No hand waving arguments are needed to derive the exchange terms. It seems, that for the first time the multiplicity of electrons in the orbital overlaps are included in the numerical treatment. Electron capture e + p --> n + neutrino is proportional to the probability to find the captured electron in the parent atom at the nucleus. Non-relativistically this is only possible for ns1/2 electron states. Relativistically also p1/2 electrons have a probability to be at the nucleus due to the lower part of the relativistic electron spinor, which does not disappear at the ...

  11. On the cascade capture of electrons at donors in GaAs quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Aleshkin, V. Ya., E-mail: aleshkin@ipmras.ru [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    2015-09-15

    The impact parameter for the cascade capture of electrons at a charged donor in a GaAs quantum well is calculated. A simple approximate analytical expression for the impact parameter is suggested. The temperature dependence of the impact parameter for the case of electron scattering by the piezoelectric potential of acoustic phonons is determined.

  12. DOUBLE ELECTRON-CAPTURE INTO HIGHLY CHARGED IONS - CORRELATED OR INDEPENDENT

    NARCIS (Netherlands)

    POSTHUMUS, JH; LUKEY, P; MORGENSTERN, R

    1991-01-01

    We propose an independent-electron model for describing quantitatively the population of doubly excited (nlnl') states formed by two-electron capture into multiply charged ions. Population probabilities calculated by this model reproduce experimentally determined ones if one assumes that the

  13. THE INFLUENCE OF ANGULAR-MOMENTUM ON DOUBLE ELECTRON-CAPTURE BY HIGHLY CHARGED IONS

    NARCIS (Netherlands)

    POSTHUMUS, JH; LUKEY, P; MORGENSTERN, R

    1992-01-01

    Double electron capture during collisions of highly charged ions with H-2 or He is studied by measuring and analysing energy spectra of the resulting autoionization electrons and by comparing the experimentally determined population probabilities for the various states with those calculated from a

  14. Axisymmetric Magnetic Fields, Electron Capture and Pycnonuclear Reactions in Magnetized White Dwarfs

    CERN Document Server

    Otoniel, Edson; Malheiro, Manuel; Schramm, Stefan; Weber, Fridolin

    2016-01-01

    In this work, we study the properties of magnetized white dwarfs taking into account possible instabilities due to electron capture and pycnonuclear fusion reactions in the cores of such objects. The structure of white dwarfs is obtained by solving the Einstein-Maxwell equations with a poloidal magnetic field in a fully general relativistic approach. The stellar interior is composed of a regular crystal lattice made of carbon ions immersed in a degenerate relativistic electron gas. The onsets of electron capture reactions and pycnonuclear reactions are determined with and without magnetic fields. We find that magnetized white dwarfs violate the standard Chandrasekhar mass limit significantly, even when electron capture and pycnonuclear instabilities are present in the stellar interior. We obtain a maximum white dwarf mass of around $2.12\\,M_{\\odot}$ with a central magnetic field of $\\sim 1.74\\times 10^{14}$G, which indicates that magnetized white dwarfs may be the progenitor candidates of superluminous type I...

  15. Neutrinoless double positron decay and positron emitting electron capture in the interacting boson model

    CERN Document Server

    Barea, J; Iachello, F

    2015-01-01

    Neutrinoless double-$\\beta$ decay is of fundamental importance for determining the neutrino mass. Although double electron ($\\beta^-\\beta^-$) decay is the most promising mode, in very recent years interest in double positron ($\\beta^+\\beta^+$) decay, positron emitting electron capture ($EC\\beta^+$), and double electron capture ($ECEC$) has been renewed. We present here results of a calculation of nuclear matrix elements for neutrinoless double-$\\beta^+$ decay and positron emitting electron capture within the framework of the microscopic interacting boson model (IBM-2) for $^{58}$Ni, $^{64}$Zn, $^{78}$Kr, $^{96}$Ru, $^{106}$Cd, $^{124}$Xe, $^{130}$Ba, and $^{136}$Ce decay. By combining these with a calculation of phase space factors we calculate expected half-lives.

  16. Measurements of Pair Production and Electron Capture from the Continuum in Heavy Particle Collisions

    CERN Multimedia

    2002-01-01

    % WA99 \\\\ \\\\ Large transient Coulomb fields, which are generated in collisions of high-Z systems at sufficiently high energies, lead to copious production of electron-positron pairs. It has been suggested that these lepton pairs might mask signals arising from plasma phase interaction. Pair-production cross-sections have been calculated by several authors with results that differ significantly from each other. For very heavy ions and high energies, multiple pairs are expected to be formed even in single peripheral collisions. Perturbative and nonperturbative treatments lead to various predictions for the fractions of multiple pair formation out of the total cross-sections. Some of the electrons produced will be captured into bound states of the ion, thereby, reducing its charge state by one unit. This process which has been termed $^{\\prime\\prime}$Electron Capture from Pair Production$^{\\prime\\prime}$, represents the only electron capture process which increases with energy, and as such, will dominate all oth...

  17. Search for new candidates for the neutrino-oriented mass determination by electron-capture

    CERN Multimedia

    Herfurth, F; Boehm, C; Blaum, K; Beck, D

    2008-01-01

    This proposal is part of an extended program dedicated to the neutrino-mass determination in the electron-capture sector, which aims at ultra-precise mass measurements by Penning traps in combination with cryogenic micro-calorimetry for atomic de-excitation measurements. Here, precise mass measurements with ISOLTRAP are proposed for the orbital electron-capture nuclides $^{194}$Hg and $^{202}$Pb, as well as their daughters, with the goal to determine accurately their Q-values. These values are expected to be the smallest ones among a great variety of known electron-capture precursors. Therefore, these nuclides are strong candidates for an improved electron-neutrino mass determination. We ask for 8 shifts of on-line beam at ISOLDE for mass measurements of $^{194}$Hg, $^{194}$ Au, $^{202}$Pb, and $^{202}$Tl at ISOLTRAP.

  18. Effect of piezoelectric field of threading dislocations on electron transport and capture in nitride semiconductors

    Science.gov (United States)

    Romanov, Dmitri; Auner, Gregory

    2001-03-01

    In nitride semiconductor structures, stress is known to induce considerable electric fields due to piezoelectric effect. We consider an AlN layer grown on a sapphire substrate and containing a number of threading dislocations. Most them are edge dislocations running in the growth direction. The strain field of such a dislocation results in electric field aligned with the dislocation axis and having alternate directions in the areas of compression and tension. These electric fields make for anisotropic electron diffusion in the layer. They also change the rates of electron capture by impurities, depending on the distance to the dislocation core. We apply these results to photoexcited electrons in a GaN/AlN quantum dot system where the dot nucleation occurred preferably in the tension regions near the dislocations [1]. The biased diffusion leads to photoinduced polarization of the dot-containing layer even in the absence of external electric field. [1] J.L. Rouviere, J. Simon, N. Pelekanos, B. Daudin, and G. Feuillet, Appl. Phys. Lett., 75, 2632-2634 (1999)

  19. Neutrino Energy Loss by Electron Capture on Nucleus 56Mn, 56Fe, 56Co and 56Ni in Strong Electron Screening

    Institute of Scientific and Technical Information of China (English)

    LIU Jing-Jing; LUO Zhi-Quan

    2007-01-01

    Based on the p-f shell model, the neutrino energy loss rates for nucleus 56Mn, 56Fe, 56Co and 56Ni in the electron capture process are canvassed in and not in a strong electron screening. The results show that the neutrino energy loss rates for 56Mn, 56Fe, 56Co and 56Ni decrease about 15%, 10%, 60% and 1 order of magnitude correspondinglyat the temperature T9 = 15 and even debase 2 orders of magnitude at the temperature T9 = 1.

  20. Development of holmium-163 electron-capture spectroscopy with transition-edge sensors

    CERN Document Server

    Croce, M P; Mocko, V; Kunde, G J; Birnbaum, E R; Bond, E M; Engle, J W; Hoover, A S; Nortier, F M; Pollington, A D; Taylor, W A; Weisse-Bernstein, N R; Wolfsberg, L E; Hays-Wehle, J P; Schmidt, D R; Swetz, D S; Ullom, J N; Barnhart, T E; Nickles, R J

    2015-01-01

    Calorimetric decay energy spectroscopy of electron-capture-decaying isotopes is a promising method to achieve the sensitivity required for electron neutrino mass measurement. The very low total nuclear decay energy (QEC < 3 keV) and short half-life (4570 y) of 163Ho make it attractive for high-precision electron capture spectroscopy (ECS) near the kinematic endpoint, where the neutrino momentum goes to zero. In the ECS approach, an electron-capture-decaying isotope is embedded inside a microcalorimeter designed to capture and measure the energy of all the decay radiation except that of the escaping neutrino. We have developed a complete process for proton-irradiation-based isotope production, isolation, and purification of 163Ho. We have developed transition-edge sensors for this measurement and methods for incorporating 163Ho into high-resolution microcalorimeters, and have measured the electron-capture spectrum of 163Ho. We present our work in these areas and discuss the measured spectrum and its compari...

  1. Absolute measurements of electron capture cross sections of C3+ from atomic and molecular hydrogen

    Science.gov (United States)

    Sant'Anna, M. M.; Melo, W. S.; Santos, A. C. F.; Shah, M. B.; Sigaud, G. M.; Montenegro, E. C.

    2000-02-01

    Absolute measurements of single- and double-electron-capture cross sections by C3+ projectiles on atomic and molecular hydrogen targets were performed for projectile energies between 1.0 and 3.5 MeV for the single- and 1.0 and 2.0 MeV for the double-capture processes. The icons/Journals/Common/sigma" ALT="sigma" ALIGN="TOP"/> H /icons/Journals/Common/sigma" ALT="sigma" ALIGN="TOP"/> H2 cross section ratios were measured using an absolutely calibrated tungsten-tube furnace for the production of atomic hydrogen. The single-capture data are compared with calculations based on the boundary-corrected first Born approximation, the eikonal approximation and a semiclassical model, presenting a good overall agreement. Calculations for the double capture using an analytical expression, obtained within the independent electron approximation and based on the same semiclassical model, give a reasonable qualitative description of the data.

  2. Double electron capture by protons in collisions with H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Salazar-Zepeda, M.H. [Departamento de Fisica, Centro Universitario de Ciencias Exactas e Ingenieria de la Universidad de Guadalajara, Boulevard Marcelino Garcia Barragan 1421, Colonia Olimpica, Codigo Postal 44430, Guadalajara, Jalisco (Mexico); Gleason, Cristian [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Avenida Universidad 1001, Colonia Chamilpa, Codigo Postal 62209, Cuernavaca, Morelos (Mexico); Gonzalez, Eduardo; Gonzalez-Magana, O. [Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Universidad 3000, Circuito Exterior SN, Codigo Postal 04510, Ciudad Universitaria (Mexico); Hinojosa, Guillermo, E-mail: hinojosa@fis.unam.m [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Avenida Universidad SN, Colonia Chamilpa, Apartado Postal 48-3, Cuernavaca 62210 (Mexico)

    2010-05-15

    Double electron capture of protons in collisions with molecular hydrogen in the energy range 1.5-10 keV was studied by measuring the resulting H{sup -} velocity distributions. In this paper, a technique that provides experimental evidence about double capture mechanisms is proposed. In addition, cross-sections for this process were measured in the energy range of 1-5 keV.

  3. Single-electron capture in He[sup 2+]-D[sub 2] collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, D.; Dagnac, R. (Toulouse-3 Univ., 31 (France))

    1994-02-14

    Doubly differential cross sections of single-electron capture were measured for He[sup 2+] impinging on a molecular deuterium target. The investigated collision energies are 4, 6 and 8 keV and the scattering angles range from 10' to 2[sup o]30' (laboratory frame). The exothermic capture leading to He[sup +] (1s) + D[sub 2][sup +*] was found to be the most important process at low energies and angles, whereas the endothermic channels leading to dissociative capture become the main processes at high scattering angles, i.e. at small impact parameters. (author).

  4. Systematic study of proton capture rates for Mo and Cd isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Bajpeyi, Awanish; Shukla, A. [Rajiv Gandhi Institute of Petroleum Technology, Department of Physics, Raebareli (India); Koning, A.J. [Nuclear Research and Consultancy Group NRG, Petten (Netherlands); Aaberg, Sven [Lund University, Mathematical Physics, P.O. Box 118, Lund (Sweden)

    2015-12-15

    Proton capture reactions play a very important role in the understanding of nucleosynthesis. In the present work, p-capture reactions have been studied coherently with nuclear structure for the nuclei under consideration. We have calculated proton capture cross sections and S-factor for relevant isotopes of molybdenum and cadmium in the energy range 2.0 to 4.5 Mev. Calculated results for nuclear structure as well reaction rates are compared with the available experimental and theoretical results and are found to be in good agreement. (orig.)

  5. Double K-shell vacancy production in the electron capture decay of 139Ce

    Science.gov (United States)

    Hindi, M. M.; Kozub, R. L.

    1991-02-01

    The probability of double K-shell vacancy production in the electron capture decay of 139Ce to the 166-keV level of 139La has been investigated. Triple coincidences between the 166-keV gamma ray, the La satellite Kα x ray, and the La hypersatellite Kα x ray were measured using two intrinsic Ge detectors. We looked for the sum of two of the three radiations in one detector in coincidence with the third radiation in the other detector. The probability of double K-shell vacancy production per K-shell electron capture (PKK) was found to be (2.0+/-1.6)×10-6. From this and the known PKK for 131Cs we estimate a probability for zero K-shell vacancy production (shakedown) per K-shell electron capture of <~2.4×10-5 for 139Ce.

  6. Search for Two-Neutrino Double Electron Capture of $^{124}$Xe with XENON100

    CERN Document Server

    Aprile, E; Agostini, F; Alfonsi, M; Amaro, F D; Anthony, M; Arneodo, F; Barrow, P; Baudis, L; Bauermeister, B; Benabderrahmane, M L; Berger, T; Breur, P A; Brown, A; Brown, E; Bruenner, S; Bruno, G; Budnik, R; Bütikofer, L; Calvén, J; Cardoso, J M R; Cervantes, M; Cichon, D; Coderre, D; Colijn, A P; Conrad, J; Cussonneau, J P; Decowski, M P; de Perio, P; Di Gangi, P; Di Giovanni, A; Diglio, S; Duchovni, E; Fei, J; Ferella, A D; Fieguth, A; Franco, D; Fulgione, W; Rosso, A Gallo; Galloway, M; Gao, F; Garbini, M; Geis, C; Goetzke, L W; Greene, Z; Grignon, C; Hasterok, C; Hogenbirk, E; Itay, R; Kaminsky, B; Kessler, G; Kish, A; Landsman, H; Lang, R F; Lellouch, D; Levinson, L; Calloch, M Le; Levy, C; Lin, Q; Lindemann, S; Lindner, M; Lopes, J A M; Manfredini, A; Undagoitia, T Marrodán; Masbou, J; Massoli, F V; Masson, D; Mayani, D; Meng, Y; Messina, M; Micheneau, K; Miguez, B; Molinario, A; Murra, M; Naganoma, J; Ni, K; Oberlack, U; Orrigo, S E A; Pakarha, P; Pelssers, B; Persiani, R; Piastra, F; Pienaar, J; Piro, M -C; Plante, G; Priel, N; Rauch, L; Reichard, S; Reuter, C; Rizzo, A; Rosendahl, S; Rupp, N; Santos, J M F dos; Sartorelli, G; Scheibelhut, M; Schindler, S; Schreiner, J; Schumann, M; Lavina, L Scotto; Selvi, M; Shagin, P; Silva, M; Simgen, H; Sivers, M v; Stein, A; Thers, D; Tiseni, A; Trinchero, G; Tunnell, C D; Wall, R; Wang, H; Weber, M; Wei, Y; Weinheimer, C; Wulf, J; Zhang, Y

    2016-01-01

    Two-neutrino double electron capture is a rare nuclear decay where two electrons are simultaneously captured from the atomic shell. For $^{124}$Xe this process has not yet been observed and its detection would provide a new reference for nuclear matrix element calculations. We have conducted a search for two-neutrino double electron capture from the K-shell of $^{124}$Xe using 7636 kg$\\cdot$d of data from the XENON100 dark matter detector. Using a Bayesian analysis we observed no significant excess above background, leading to a lower 90 % credibility limit on the half-life $T_{1/2}>6.5\\times10^{20}$ yr. We also evaluated the sensitivity of the XENON1T experiment, which is currently being commissioned, and find a sensitivity of $T_{1/2}>6.1\\times10^{22}$ yr after an exposure of 2 t$\\cdot$yr.

  7. Microscopic Calculation of Total Ordinary Muon Capture Rates for Medium-weight and Heavy Nuclei

    CERN Document Server

    Kuzmin, V A; Junker, K; Ovchinnikova, A A

    2002-01-01

    Total Ordinary Muon Capture (OMC) rates are calculated on the basis of the Quasiparticle Random Phase Approximation for several spherical nuclei from 90^Zr to 208^Pb. It is shown that total OMC rates calculated with the free value of the axial-vector coupling constant g_A agree well with the experimental data for medium-size nuclei and exceed considerably the experimental rates for heavy nuclei. The sensitivity of theoretical OMC rates to the nuclear residual interactions is discussed.

  8. Unusual distance dependences of electron transfer rates.

    Science.gov (United States)

    Kuss-Petermann, Martin; Wenger, Oliver S

    2016-07-28

    Usually the rates for electron transfer (kET) decrease with increasing donor-acceptor distance, but Marcus theory predicts a regime in which kET is expected to increase when the transfer distance gets longer. Until recently, experimental evidence for such counter-intuitive behavior had been very limited, and consequently this effect is much less well-known than the Gaussian free energy dependence of electron transfer rates leading to the so-called inverted driving-force effect. This article presents the theoretical concepts that lead to the prediction of electron transfer rate maxima at large donor-acceptor distances, and it discusses conditions that are expected to favor experimental observations of such behavior. It continues with a consideration of specific recent examples in which electron transfer rates were observed to increase with increasing donor-acceptor distance, and it closes with a discussion of the importance of this effect in the context of light-to-chemical energy conversion.

  9. A new insight into neutrino energy loss by electron capture of iron group nuclei in magnetars surface

    CERN Document Server

    Liu, Jing-Jing

    2016-01-01

    Based on the relativistic mean-field effective interactions theory, and Lai dong model \\citep{b37, b38, b39}, we discuss the influences of superstrong magnetic fields (SMFs) on electron Fermi energy, nuclear blinding energy, and single-particle level structure in magnetars surface. By using the method of Shell-Model Monte Carlo (SMMC), and the Random Phase Approximation (RPA) theory, we detailed analyze the neutrino energy loss rates(NELRs) by electron capture (EC) for iron group nuclei in SMFs.

  10. The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

    CERN Document Server

    Dzhioev, Alan A; Stoyanov, Ch

    2016-01-01

    We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme-TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, $^{56}$Fe, the Skyrme-TQRPA approach is applied to analyze thermal effects on the strength function of GT$_+$ transitions which dominate electron capture at $E_e\\le 30$~MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are compared with those of the other model calculations.

  11. The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

    Energy Technology Data Exchange (ETDEWEB)

    Dzhioev, Alan A., E-mail: dzhioev@theor.jinr.ru; Vdovin, A. I., E-mail: vdovin@theor.jinr.ru [JINR, Bogoliubov Laboratory of Theoretical Physics (Russian Federation); Stoyanov, Ch., E-mail: stoyanov@inrne.bas.bg [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria)

    2016-11-15

    We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme–TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, {sup 56}Fe, the Skyrme–TQRPA approach is applied to analyze thermal effects on the strength function of GT{sub +} transitions which dominate electron capture at E{sub e} ≤ 30 MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are comparedwith those of the other model calculations.

  12. The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

    Science.gov (United States)

    Dzhioev, Alan A.; Vdovin, A. I.; Stoyanov, Ch.

    2016-11-01

    We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme-TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, 56Fe, the Skyrme-TQRPA approach is applied to analyze thermal effects on the strength function of GT+ transitions which dominate electron capture at E e ≤ 30 MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are comparedwith those of the other model calculations.

  13. Double K-shell vacancy production in the electron capture decay of 125I

    Science.gov (United States)

    Hindi, M. M.; Kozub, R. L.

    1992-03-01

    We have measured the probability of double K-shell vacancy production in the electron capture decay of 125I to the 35-keV level of 125Te. The probability was deduced from the number of triple coincidences between the Te hypersatellite and satellite x rays produced in filling the double vacancy, and the subsequent normal x ray accompanying the K internal conversion of the 35-keV level. The probability of double K-shell vacancy production per K-shell electron capture (PKK) was found to be (1.35+/-0.15)×10-5.

  14. A search for the radiative neutrinoless double electron capture of $^{58}$Ni

    CERN Document Server

    Lehnert, B; Frotscher, A; Michel, T; Zuber, K

    2016-01-01

    A search for the radiative neutrinoless double electron capture with single \\gray\\ emission has been performed in $^{58}$Ni. Gamma radiation from a 7286 g nickel sample in natural isotope composition was measured for 58.3 d with an ultra low background HPGe detector in the Felsenkeller underground laboratory in Dresden, Germany. A new lower half-life limit of $2.1 \\times 10^{21}$ yr (90% CL) was obtained for this decay mode. This half-life limit is two orders of magnitude higher than the existing limit for $^{58}$Ni and among the best half-life limits for neutrinoless double electron capture decays.

  15. Electronic data capture platform for clinical research based on mobile phones and near field communication technology.

    Science.gov (United States)

    Morak, Jürgen; Schwetz, Verena; Hayn, Dieter; Fruhwald, Friedrich; Schreier, Gunter

    2008-01-01

    Electronic data capture systems support data acquisition for clinical research and enable the evaluation of new investigational medical devices. In case of evaluating a device the most challenging part is the user interface i.e. the solution how to acquire the data within a clinical setting and to synchronize them with a web-based data centre. The aim of this paper is to describe the development of an electronic data capture system with a mobile data input solution based on mobile phones and Near Field Communication technology. This system was evaluated within a real clinical setting and demonstrated high usability, security and reliability.

  16. High Count Rate Electron Probe Microanalysis

    Science.gov (United States)

    Geller, Joseph D.; Herrington, Charles

    2002-01-01

    Reducing the measurement uncertainty of quantitative analyses made using electron probe microanalyzers (EPMA) requires a careful study of the individual uncertainties from each definable step of the measurement. Those steps include measuring the incident electron beam current and voltage, knowing the angle between the electron beam and the sample (takeoff angle), collecting the emitted x rays from the sample, comparing the emitted x-ray flux to known standards (to determine the k-ratio) and transformation of the k-ratio to concentration using algorithms which includes, as a minimum, the atomic number, absorption, and fluorescence corrections. This paper discusses the collection and counting of the emitted x rays, which are diffracted into the gas flow or sealed proportional x-ray detectors. The representation of the uncertainty in the number of collected x rays collected reduces as the number of counts increase. The uncertainty of the collected signal is fully described by Poisson statistics. Increasing the number of x rays collected involves either counting longer or at a higher counting rate. Counting longer means the analysis time increases and may become excessive to get to the desired uncertainty. Instrument drift also becomes an issue. Counting at higher rates has its limitations, which are a function of the detector physics and the detecting electronics. Since the beginning of EPMA analysis, analog electronics have been used to amplify and discriminate the x-ray induced ionizations within the proportional counter. This paper will discuss the use of digital electronics for this purpose. These electronics are similar to that used for energy dispersive analysis of x rays with either Si(Li) or Ge(Li) detectors except that the shaping time constants are much smaller. PMID:27446749

  17. Electron Capture and Electron Transport by Fast Ions Penetrating Solids: An open Quantum System Approach with Sources and Sinks

    Energy Technology Data Exchange (ETDEWEB)

    Seliger, M. [Institute of Physics, Karl-Franzens Universitat Graz

    2007-03-01

    We present a joint theoretical and experimental study of the time evolution of electronic states of highly charged hydrogenic ions formed by capture during transmission through solids as they undergo multiple collisions and radiative decay. For this transport problem we have developed an inhomogeneous nonunitary Lindblad master equation that allows for a description of open quantum systems with both sinks (electron loss) and source (capture) present. We apply this theoretical framework to study transient coherences created in electron capture by 13.6 MeV/amu Ar18+ ions transmitted through amorphous carbon foils and decoherence during subsequent interaction with the foil. In the limit of thin targets we can directly probe electron capture cross sections under single collision conditions, while for thicker targets we follow the partially coherent dynamics of the open quantum system in interaction with the solid as a function of interaction time. The calculated results are in close agreement with experimental data obtained at the LISE facility in GANIL. Photon intensities from excited argon ions were determined through high resolution x-ray spectroscopy in which individual fine structure components were resolved. Measurements were performed for a wide range of carbon foil thickness to study the time development of the excited state populations.

  18. Evaluation of a mandatory quality assurance data capture in anesthesia: a secure electronic system to capture quality assurance information linked to an automated anesthesia record.

    Science.gov (United States)

    Peterfreund, Robert A; Driscoll, William D; Walsh, John L; Subramanian, Aparna; Anupama, Shaji; Weaver, Melissa; Morris, Theresa; Arnholz, Sarah; Zheng, Hui; Pierce, Eric T; Spring, Stephen F

    2011-05-01

    Efforts to assure high-quality, safe, clinical care depend upon capturing information about near-miss and adverse outcome events. Inconsistent or unreliable information capture, especially for infrequent events, compromises attempts to analyze events in quantitative terms, understand their implications, and assess corrective efforts. To enhance reporting, we developed a secure, electronic, mandatory system for reporting quality assurance data linked to our electronic anesthesia record. We used the capabilities of our anesthesia information management system (AIMS) in conjunction with internally developed, secure, intranet-based, Web application software. The application is implemented with a backend allowing robust data storage, retrieval, data analysis, and reporting capabilities. We customized a feature within the AIMS software to create a hard stop in the documentation workflow before the end of anesthesia care time stamp for every case. The software forces the anesthesia provider to access the separate quality assurance data collection program, which provides a checklist for targeted clinical events and a free text option. After completing the event collection program, the software automatically returns the clinician to the AIMS to finalize the anesthesia record. The number of events captured by the departmental quality assurance office increased by 92% (95% confidence interval [CI] 60.4%-130%) after system implementation. The major contributor to this increase was the new electronic system. This increase has been sustained over the initial 12 full months after implementation. Under our reporting criteria, the overall rate of clinical events reported by any method was 471 events out of 55,382 cases or 0.85% (95% CI 0.78% to 0.93%). The new system collected 67% of these events (95% confidence interval 63%-71%). We demonstrate the implementation in an academic anesthesia department of a secure clinical event reporting system linked to an AIMS. The system enforces

  19. HE2+-HE COLLISIONS - ONE-ELECTRON CAPTURE AND TARGET-ION EXCITATION

    NARCIS (Netherlands)

    FOLKERTS, HO; BLIEK, FW; MENG, L; OLSON, RE; MORGENSTERN, R; VONHELLERMANN, M; SUMMERS, HP; HOEKSTRA, R

    1994-01-01

    By means of photon emission spectroscopy we have studied state selective one-electron capture and target-ion excitation in collisions of He-2+ with He. The collision energy has been varied from 1 to 75 keV amu-1 Four-body classical trajectory Monte Carlo calculations have been performed in the energ

  20. Transition Operators Entering Neutrinoles Double Electron Capture to Excited Nuclear States

    CERN Document Server

    Vergados, J D

    2011-01-01

    We construct the effective transition operators relevant for neutrinoless double electron capture leading to final nuclear states different than $0^{+}$. From the structure of these operators we see that, if such a process is observed experimentally, it will be very helpful in singling out the very important light neutrino mass contribution from the other lepton violating mechanisms

  1. First state selective electron capture measurements with trapped highly charged ions

    NARCIS (Netherlands)

    Bliek, F.W.; Woestenenk, G.R.; Hoekstra, R.A.; Morgenstern, R.W.H.

    1997-01-01

    The first state selective electron capture cross section measurements at eV energies are reported for collisions between C4+ ions and H-2 molecules. The cross sections are measured in a crossed beam experiment by means of Photon Emission Spectroscopy. The ion beams are decelerated in an octopole ion

  2. Beta decay and muon capture rates in a self-consistent relativistic framework

    Energy Technology Data Exchange (ETDEWEB)

    Marketin, Tomislav; Paar, Nils; Niksic, Tamara; Vretenar, Dario [Physics Department, Faculty of Science, University of Zagreb (Croatia); Ring, Peter [Physik-Department, Technische Universitaet Muenchen, D-85748 Muenchen (Germany)

    2009-07-01

    A fully consistent calculation of muon capture and beta decay rates is presented, based on a microscopic theoretical framework describing the semileptonic weak interaction processes. Nuclear ground state is determined using the Relativistic Hartree-Bogolyubov (RHB) model with density dependent meson-nucleon coupling constants, and transition rates are calculated via proton-neutron relativistic quasiparticle RPA using the same interaction as in the RHB equations. Muon capture rates are calculated for a wide range of nuclei along the valley of stability, from {sup 12}C to {sup 244}Pu, with accuracy of approximately 30%, using the interaction DD-ME2. Previous studies of beta decay rates have only taken into account Gamow-Teller transitions. We extend this approach by including forbidden transitions and systematically study their contribution to decay rates of exotic nuclei along the r-process path, which are important for constraining the conditions in which nucleosynthesis takes place.

  3. Correlations and total muon capture rates. [Primakoff effect, isospin, shell model

    Energy Technology Data Exchange (ETDEWEB)

    Mekjian, A.

    1978-08-01

    The total muon capture rate for s-wave muons can be accounted for by the Primakoff expression which gives the dependence of this rate on the mass number A and the proton number Z of the absorbing nucleus. The expression is a simple three parameter phenomenological formulae which accurately describes these rates from light weight nuclei to heavy nuclei. These parameters relate to the isospin structure of the squared isovector operator which appears in a sum rule approach to such rates. A microscopic analysis of the parameters appearing in the capture rate expression is presented in the light of recent developments concerning photonuclear reactions. A shell model analysis is given and it is found that the predictions of the unperturbed shell model and also Hartree-Fock theory are in complete disagreement with the data. Considerable improvement is obtained when long range correlations are included in the ground state wave function of the absorbing nucleus. 21 references.

  4. Nuclear halo effect on nucleon capture reaction rates at stellar energies

    Institute of Scientific and Technical Information of China (English)

    Liu Zu-Hua; Zhou Hong-Yu

    2005-01-01

    The capture cross sections at stellar energies are very difficult to measure directly. Hence, data are usually evaluated by using indirect methods or extrapolations from the experimental data obtained at the lowest possible energies. The asymptotic normalization coefficient (ANC) approach of the transfer reactions provides a reliable way for the determination of the capture cross sections at stellar energies. By virtue of its reliability, we have calculated the capture cross sections of the 10Be(n,γ)11Be reaction by using nuclear ANC method. 11Be is a well-known neutron halo nucleus with two weakly bound states. As a typical example, we have shown that the radiative cross sections for a nucleon captured into a halo state are obviously enhanced. The enormous enhancement of the capture cross section is just due to the large overlap of the incident neutron wave with the extended tail of the halo. The 10Be(n,γ)11Be capture reaction is involved in the inhomogeneous big-bang nucleosynthesis. We have evaluated its reaction rates at stellar energies with the nuclear ANC method.

  5. A systematic calculation of muon capture rates in the number projected QRPA

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Danilo Sande; Samana, Arturo Rodolfo; Dimarco, Alejandro Javier [Universidade Estadual de Santa Cruz (UESC), Itabuna, BA (Brazil); Krmpotic, Francisco [Universidad Nacional de La Plata (UNLP), Buenos Aires (Argentina)

    2011-07-01

    Full text: The pairing correlations at the level of the one-body transition matrix elements were introduced ad-hoc by Zinner et al. in the evaluation the total muon capture rates in a large number of nuclei with 6 < Z < 94, employing the random phase approximation (RPA). The quasiparticle RPA (QRPA) formalism is a full self-consistent procedure to describe consistently the short range correlations as pairing and those from the large range correlations handled with RPA. In this way, the relativistic QRPA (RQRPA) was applied in the calculation of total muon capture rates on a large set of nuclei from {sup 12}C to {sup 244}Pu, for which experimental values are available. Moreover, it was shown that the conservation of number of particles plays an important role on the weak interactions processes in nuclei with N {approx_equal} Z. This issue was not taken into account in the previous QRPA calculations. We show that the projection procedure is important in the muon capture rate and neutrino nucleus cross section in {sup 56}Fe. Therefore, in the present work we do a systematic study of the muon capture rates with nuclei with 12 {<=} A {<=} 56 masses within the projected QRPA (PQRPA) because it is the only RPA model that treats the Pauli Principle correctly. (author)

  6. Interatomic Coulombic electron capture in atomic, molecular, and quantum dot systems

    Directory of Open Access Journals (Sweden)

    Bande Annika

    2015-01-01

    Full Text Available The interatomic Coulombic electron capture (ICEC process has recently been predicted theoretically for clusters of atoms and molecules. For an atom A capturing an electron e(ε it competes with the well known photorecombination, because in an environment of neutral or anionic neighboring atoms B, A can transfer its excess energy in the ultrafast ICEC process to B which is then ionized. The cross section for e(ε + A + B → A− + B+ + e(ε′ has been obtained in an asymptotic approximation based on scattering theory for several clusters [1,2]. It was found that ICEC starts dominating the PR for distances among participating species of nanometers and lower. Therefore, we believe that the ICEC process might be of importance in the atmosphere, in biological systems, plasmas, or in nanostructured materials. As an example for the latter, ICEC has been investigated by means of electron dynamics in a model potential for semiconductor double quantum dots (QDs [3]. In the simplest case one QD captures an electron while the outgoing electron is emitted from the other. The reaction probability for this process was found to be relatively large.

  7. Single-photon emission associated with double electron capture in F9+ + C collisions

    CERN Document Server

    Elkafrawy, Tamer; Tanis, John A; Warczak, Andrzej

    2016-01-01

    Radiative double electron capture (RDEC), the one-step process occurring in ion-atom collisions, has been investigated for bare fluorine ions colliding with carbon. RDEC is completed when two target electrons are captured to a bound state of a projectile simultaneously with the emission of a single photon. This work is a follow-up to our earlier measurement of RDEC for bare oxygen projectiles, thus providing a recipient system free of electron-related Coulomb fields in both cases and allowing for the comparison between the two collision systems as well as with available theoretical studies. The most significant mechanisms of x-ray emission that may contribute to the RDEC energy region as background processes are also addressed.

  8. Experimental investigations of electron capture from atomic hydrogen and deuterium by alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Gay, T.J.; Park, J.T.

    1992-01-01

    We report progress made during the period 15 September 1991--14 September 1992 on the project Experimental Investigations of Electron Capture from Atomic Hydrogen and Deuterium by Alpha Particles''. In the past year we have developed reliable, narrow energy spread, high-current sources of He[sup ++] based on direct-current magentron and electron-cyclotron resonance discharges. These sources have been proven on our test bench accelerator which has been upgraded to also allow us to test atomic hydrogen effusive targets. We have thus made substantial progress toward our goal of studying single electron capture from atomic hydrogen by doubly-ionized helium. A research plan for the upcoming year is also presented.

  9. Double K-shell ionization in the electron capture decay of 55Fe

    Science.gov (United States)

    Campbell, J. L.; Maxwell, J. A.; Teesdale, W. J.

    1991-04-01

    The probability per K capture for double K-shell ionization in the electron capture decay of 55Fe was obtained by fitting a model spectrum to the x-ray spectrum recorded to very high statistics in a high-resolution Si(Li) detector. The result, PKK=(1.3+/-0.2)×10-4, confirms the trend wherein experimental data decrease smoothly with Z, and are intermediate between the theoretical predictions of Intemann and of Suzuki and Law. Corrections to some recently published PKK values reconcile them with this trend.

  10. Double electron capture of He sup 2+ from He at high velocity

    Energy Technology Data Exchange (ETDEWEB)

    Schuch, R.; Justiniano, E.; Vogt, H. (Heidelberg Univ. (Germany, F.R.). Physikalisches Inst.); Deco, G.; Gruen, N. (Giessen Univ. (Germany, F.R.). Inst. fuer Theoretische Physik)

    1991-03-14

    The double electron capture process by He{sup 2+} ions in collisions with helium is studied in the high velocity regime with the measurement of total cross sections at 1.5, 4 and 6 MeV beam energy and angular differential cross sections for 1.5 MeV. The experimental results compare well with theoretical calculations which include correlation effects in the initial and final He ground states for the derivation of the capture amplitude in a continuum distorted-wave approximation. (author).

  11. Electron capture strength on odd-A nucleus $\\mathbf{^{59}}$Co in explosive astrophysical environment

    CERN Document Server

    Rahman, Muneeb-Ur

    2014-01-01

    The Gamow-Teller (GT) transitions within massive stars play sumptuous role in the dynamics of core collapse supernovae. GT strength distributions and electron capture rates have been calculated for odd-A nucleus $^{59}$Co within the proton-neutron quasiparticles random phase approximation (pn-QRPA) formalism. The pn-QRPA results are compared with other model calculations and (n, p) reaction experiment carried out at TRIUMF charge-exchange facility. The pn-QRPA calculated a total $B(GT_{+})$ strength of 3.3 for $^{59}$Co to be compared with the shell model value of 2.5 and the 1.9 $\\pm$ 0.1 in the (n, p) charge-exchange reaction. Aufderheide et. al. \\cite{Aufderheide93} extracted total strength equaling 2.4 $\\pm$ 0.3. The placement of GT centroid at 5.6 MeV by the pn-QRPA model is in reasonable agreement with the shell model centroid at 5.1 MeV whereas the measured GT centroid was placed at 4.4 $\\pm$ 0.3 MeV in the (n, p) experiment. Fuller, Fowler and Newman (FFN) \\cite{FFN80, FFN82, FFN82b}, placed the GT ce...

  12. Rapidly evolving faint transients from stripped-envelope electron-capture supernovae

    Science.gov (United States)

    Moriya, Takashi J.; Eldridge, J. J.

    2016-09-01

    We investigate the expected rates and bolometric light-curve properties of stripped-envelope electron-capture supernovae (ECSNe) using stellar models from the Binary Population and Spectral Synthesis code. We find that 0.8 per cent (Z = 0.020) and 1.2 per cent (Z = 0.004) of core-collapse supernovae are stripped-envelope ECSNe. Their typical ejecta masses are estimated to be about 0.3 M⊙(Z = 0.020) and 0.6 M⊙ (Z = 0.004). Assuming ECSN explosion properties from numerical explosion simulations, an explosion energy of 1.5 × 1050 erg and a 56Ni mass of 2.5 × 10-3 M⊙, we find that stripped-envelope ECSNe have a typical rise time of around 7 d (Z = 0.020) or 13 d (Z = 0.004) and peak luminosity of around 1041 ergs-1 (-13.8 mag, Z = 0.020) or 7 × 1040 erg s-1 (-13.4 mag, Z = 0.004). Their typical ejecta velocities are around 7000 km s-1 (Z = 0.020) or 5000 km s-1 (Z = 0.004). Thus, stripped-envelope ECSNe are observed as rapidly evolving faint transients with relatively small velocities. SN 2008ha-like supernovae, which are the faintest kind of SN 2002cx-like (also known as Type Iax) supernovae, may be related to stripped-envelope ECSNe.

  13. Determination of phenoxy acid herbicides in water by electron-capture and microcoulometric gas chromatography

    Science.gov (United States)

    Goerlitz, D.F.; Lamar, William L.

    1967-01-01

    A sensitive gas chromatographic method using microcoulometric titration and electron-capture detection for the analysis of 2,4-D, silvex, 2,4,5-T, and other phenoxy acid herbicides in water is described. The herbicides are extracted from unfiltered water samples (800-1,000 ml) by use of ethyl ether ; then the herbicides are concentrated and esterilied. To allow the analyst a choice, two esterilication procedures--using either boron trifluoride-methanol or diazomethane--are evaluated. Microcoulometric gas chromatography is specific for the detection of halogenated compounds such as the phenoxy acid herbicides whereas it does not respond to nonhalogenated components. Microcoulometric gas chromatography requires care and patience. It is not convenient for rapid screening of l-liter samples that contain less than 1 microgram of the herbicide. Although electroncapture gas chromatography is less selective and more critically affected by interfering substances, it is, nevertheless, convenient and more sensitive than microcoulometric gas chromatography. Two different liquid phases are used in the gas chromatographic columns--DC-200 silicone in one column and QF-1 silicone in the other. The performance of both columns is improved by the addition of Carbowax 20M. The Gas Chrom Q support is coated with the liquid phases by the 'frontal-analysis' technique. The practical lower limits for measurement of the phenoxy acid herbicides in water primarily depend upon the sample size, interferences present, anal instrumentation used. With l-liter samples of water, the practical lower limits of measurement are 10 ppt (parts per trillion) for 2,4-D and 2 ppt for silvex and 2,4,5-T when electron-capture detection is used, and approximately 20 ppt for each herbicide when analyzed by microcoulometric-titration gas chromatography. Recoveries of the herbicides immediately after addition to unfiltered water samples averaged 92 percent for 2,4-D, 90 percent for silvex, and 98 percent for 2

  14. Efficacy of trap modifications for increasing capture rates of aquatic snakes in floating aquatic funnel traps

    Science.gov (United States)

    Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L.

    2013-01-01

    Increasing detection and capture probabilities of rare or elusive herpetofauna of conservation concern is important to inform the scientific basis for their management and recovery. The Giant Gartersnake (Thamnophis gigas) is an example of a secretive, wary, and generally difficult-to-sample species about which little is known regarding its patterns of occurrence and demography. We therefore evaluated modifications to existing traps to increase the detection and capture probabilities of the Giant Gartersnake to improve the precision with which occurrence, abundance, survival, and other demographic parameters are estimated. We found that adding a one-way valve constructed of cable ties to the small funnel opening of traps and adding hardware cloth extensions to the wide end of funnels increased capture rates of the Giant Gartersnake by 5.55 times (95% credible interval = 2.45–10.51) relative to unmodified traps. The effectiveness of these modifications was insensitive to the aquatic habitat type in which they were deployed. The snout-vent length of the smallest and largest captured snakes did not vary among trap modifications. These trap modifications are expected to increase detection and capture probabilities of the Giant Gartersnake, and show promise for increasing the precision with which demographic parameters can be estimated for this species. We anticipate that the trap modifications found effective in this study will be applicable to a variety of aquatic and semi-aquatic reptiles and amphibians and improve conservation efforts for these species.

  15. First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho

    CERN Document Server

    Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

    2014-01-01

    The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...

  16. High-Rate Data-Capture for an Airborne Lidar System

    Science.gov (United States)

    Valett, Susan; Hicks, Edward; Dabney, Philip; Harding, David

    2012-01-01

    A high-rate data system was required to capture the data for an airborne lidar system. A data system was developed that achieved up to 22 million (64-bit) events per second sustained data rate (1408 million bits per second), as well as short bursts (less than 4 s) at higher rates. All hardware used for the system was off the shelf, but carefully selected to achieve these rates. The system was used to capture laser fire, single-photon detection, and GPS data for the Slope Imaging Multi-polarization Photo-counting Lidar (SIMPL). However, the system has applications for other laser altimeter systems (waveform-recording), mass spectroscopy, xray radiometry imaging, high-background- rate ranging lidar, and other similar areas where very high-speed data capture is needed. The data capture software was used for the SIMPL instrument that employs a micropulse, single-photon ranging measurement approach and has 16 data channels. The detected single photons are from two sources those reflected from the target and solar background photons. The instrument is non-gated, so background photons are acquired for a range window of 13 km and can comprise many times the number of target photons. The highest background rate occurs when the atmosphere is clear, the Sun is high, and the target is a highly reflective surface such as snow. Under these conditions, the total data rate for the 16 channels combined is expected to be approximately 22 million events per second. For each photon detection event, the data capture software reads the relative time of receipt, with respect to a one-per-second absolute time pulse from a GPS receiver, from an event timer card with 0.1-ns precision, and records that information to a RAID (Redundant Array of Independent Disks) storage device. The relative time of laser pulse firings must also be read and recorded with the same precision. Each of the four event timer cards handles the throughput from four of the channels. For each detection event, a flag is

  17. CO2 Capture Rate Sensitivity Versus Purchase of CO2 Quotas. Optimizing Investment Choice for Electricity Sector

    Directory of Open Access Journals (Sweden)

    Coussy Paula

    2014-09-01

    Full Text Available Carbon capture technology (and associated storage, applied to power plants, reduces atmospheric CO2 emissions. This article demonstrates that, in the particular case of the deployment phase of CO2 capture technology during which CO2 quota price may be low, capturing less than 90% of total CO2 emissions from power plants can be economically attractive. Indeed, for an electric power company capture technology is interesting, only if the discounted marginal cost of capture is lower than the discounted marginal cost of purchased quotas. When CO2 price is low, it is interesting to have flexibility and reduce the overall capture rate of the site, by stopping the capture system of one of the combustion trains if the site has multiple ones, or by adopting less than 90% CO2 capture rate.

  18. STRONG VELOCITY DEPENDENCE OF ELECTRON-CAPTURE IN COLLISIONS BETWEEN ALIGNED NA-ASTERISK(3P) AND HE-2+

    NARCIS (Netherlands)

    SCHLATMANN, AR; HOEKSTRA, R; MORGENSTERN, R; OLSON, RE; PASCALE, J

    1993-01-01

    By analyzing spectra of emitted photons, we have studied state-selective electron capture in collisions of He2+ on aligned Na*(3p) atoms that span the ''velocity-matching'' energy between projectile and target electron. We find a strong dependence of the capture cross sections on the Na*(3p) orbital

  19. 75 FR 8115 - In the Matter of Certain Electronic Devices Having Image Capture or Display Functionality and...

    Science.gov (United States)

    2010-02-23

    .... 5,995,767, 5,774,131, and 6,281,895. 74 FR 14157 (2009). The complainant named Eastman Kodak Company... COMMISSION In the Matter of Certain Electronic Devices Having Image Capture or Display Functionality and... sale within the United States after importation of certain electronic devices having image capture...

  20. Determination of the Neutron-Capture Rate of 17C for the R-process Nucleosynthesis

    CERN Document Server

    Heine, M; Wu, M -R; Adachi, T; Aksyutina, Y; Alcantara, J; Altstadt, S; Alvarez-Pol, H; Ashwood, N; Aumann, T; Avdeichikov, V; Barr, M; Beceiro-Novo, S; Bemmerer, D; Benlliure, J; Bertulani, C A; Boretzky, K; Borge, M J G; Burgunder, G; Caamano, M; Caesar, C; Casarejos, E; Catford, W; Cederkäll, J; Chakraborty, S; Chartier, M; Chulkov, L V; Cortina-Gil, D; Crespo, R; Pramanik, U Datta; Fernandez, P Diaz; Dillmann, I; Elekes, Z; Enders, J; Ershova, O; Estrade, A; Farinon, F; Fraile, L M; Freer, M; Freudenberger, M; Fynbo, H O U; Galaviz, D; Geissel, H; Gernhäuser, R; Göbel, K; Golubev, P; Diaz, D Gonzalez; Hagdahl, J; Heftrich, T; Heil, M; Heinz, A; Henriques, A; Holl, M; Ickert, G; Ignatov, A; Jakobsson, B; Johansson, H T; Jonson, B; Kalantar-Nayestanaki, N; Kanungo, R; Kelic-Heil, A; Knöbel, R; Kröll, T; Krücken, R; Kurcewicz, J; Kurz, N; Labiche, M; Langer, C; Bleis, T Le; Lemmon, R; Lepyoshkina, O; Lindberg, S; Machado, J; Marganiec, J; Martínez-Pinedo, G; Maroussov, V; Mostazo, M; Movsesyan, A; Najafi, A; Neff, T; Nilsson, T; Nociforo, C; Panin, V; Paschalis, S; Perea, A; Petri, M; Pietri, S; Plag, R; Prochazka, A; Rahaman, A; Rastrepina, G; Reifarth, R; Ribeiro, G; Ricciardi, M V; Rigollet, C; Riisager, K; Röder, M; Rossi, D; del Rio, J Sanchez; Savran, D; Scheit, H; Simon, H; Sorlin, O; Stoica, V; Streicher, B; Taylor, J T; Tengblad, O; Terashima, S; Thies, R; Togano, Y; Uberseder, E; Van de Walle, J; Velho, P; Volkov, V; Wagner, A; Wamers, F; Weick, H; Weigand, M; Wheldon, C; Wilson, G; Wimmer, C; Winfield, J S; Woods, P; Yakorev, D; Zhukov, M V; Zilges, A; Zuber, K

    2016-01-01

    With the R$^{3}$B-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of $^{18}$C at a projectile energy around 425~AMeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of $^{17}$C into the ground state of $^{18}$C. Those data have been used to constrain theoretical calculations for transitions populating excited states in $^{18}$C. This allowed to derive the astrophysical cross section $\\sigma^{*}_{\\mathrm{n}\\gamma}$ accounting for the thermal population of $^{17}$C target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures $T_{9}\\leq{}1$~GK. Network simulations with updated neutron-capture rates and hydrodynamics according to the neutrino-driven wind model as well as the neutron-star merger scenario reveal no pronounced influence of neutron capture of $^{17}$C on the production of second- and thi...

  1. Detailed description of exclusive muon capture rates using realistic two-body forces

    CERN Document Server

    Giannaka, P G

    2015-01-01

    Starting from state-by-state calculations of exclusive rates of the ordinary muon capture (OMC), we evaluated total muon-capture rates for a set of light- and medium-weight nuclear isotopes. We employed a version of the proton-neutron quasi-particle random phase approximation (pn-QRPA, for short) which uses as realistic nuclear forces the Bonn C-D one boson exchange potential. Special attention was paid on the percentage contribution to the total muon-capture rate of specific low-spin multipolarities resulting by summing over the corresponding multipole transitions. The nuclear method used offers the possibility of estimating separately the individual contributions to the total and partial rates of the polar-vector and axial-vector components of the weak interaction Hamiltonian for each accessible final state of the daughter nucleus. One of our main goals is to provide a reliable description of the charge changing transitions matrix elements entering the description of other similar semileptonic nuclear proce...

  2. Warm dark matter sterile neutrinos in electron capture and beta decay spectra

    CERN Document Server

    Moreno, O; Medrano, M Ramón

    2016-01-01

    We briefly review the motivation to search for sterile neutrinos in the keV mass scale, as dark matter candidates, and the prospects to find them in beta decay or electron capture spectra. We describe the fundamentals of the neutrino flavor-mass eigenstate mismatch that opens the possibility of detecting sterile neutrinos in such ordinary nuclear processes. Results are shown and discussed for the effect of heavy neutrino emission in electron capture in Holmium 163 and in two isotopes of Lead, 202 and 205, as well as in the beta decay of Tritium. Ratios of observables in different regions of the atomic de-excitation spectrum or of the charged lepton spectrum are defined that may guide the analysis of possible future measurements.

  3. The role of electron capture and energy exchange of positively charged particles passing through matter

    CERN Document Server

    Ulmer, W

    2011-01-01

    The conventional treatment of the Bethe-Bloch equation for protons accounts for electron capture at the end of the projectile track by the small Barkas correction. This is only a possible way for protons, whereas for light and heavier charged nuclei the exchange of energy and charge along the track has to be accounted for by regarding the projectile charge q as a function of the residual energy. This leads to a significant modification of the Bethe-Bloch equation, otherwise the range in a medium is incorrectly determined. The LET in the Bragg peak domain and distal end is significantly influenced by the electron capture. A rather significant result is that in the domain of the Bragg peak the superiority of carbon ions is reduced compared to protons.

  4. Experimental study of K-electron capture probability in the decay of {sup 111}In

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, N.R.; Kalyani, V.D.M.L.; Maldhusudhana Rao, P.V.; Vara Prasad, N.V.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L. [Visakhapatnam, Andhra Univ. (India). Swami Jnanananda Lab. for Nuclear Research; Chintalapudi, S.N. [Calcutt, Inter-Univ. Consortium for DAEW Facilities (India)

    1998-03-01

    The K-electron capture probability in the decay of {sup 111}In to the 416.64 keV level of the daughter nucleus {sup 111}Cd was measured to be 0.853 {+-}0.037 in agreement with the theoretical value 0.865. The experimental value is seen to be consistent with the mass prediction of the relationship due to Wapstra and Bos.

  5. Electron capture collisions involving low-energy highly-stripped projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Cocke, C.L.; Gray, T.J.; Justiniano, E.; Can, C.; Waggoner, B.; Varghese, S.L.; Mann, R. (Kansas State Univ., Manhattan (USA). Dept. of Physics)

    1983-01-01

    Recoil ions produced by fast-ion bombardment of dilute gases are in use at Kansas State University as a source of low-energy highly-charged ions to study electron capture by these projectiles on neutral targets in the 10/sup 6/-10/sup 7/ cm s/sup -1/ velocity range. A progress report on several phases of this program is summarized.

  6. Ground and excited states Gamow-Teller strength distributions of iron isotopes and associated capture rates for core-collapse simulations

    CERN Document Server

    Nabi, Jameel-Un

    2012-01-01

    This paper reports on the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions, both in the electron capture and electron decay direction, for $^{54,55,56}$Fe. The associated electron and positron capture rates for these isotopes of iron are also calculated in stellar matter. These calculations were recently introduced and this paper is a follow-up which discusses in detail the GT strength distributions and stellar capture rates of key iron isotopes. The calculations are performed within the framework of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic \\textit{state-by-state} calculation of GT strength functions and stellar capture rates which greatly increases the reliability of the results. For the first time experimental deformation of nuclei are taken into account. In the core of massive stars isotopes of iron, $^{54,55,56}$Fe, are considered to be key players in decreasing the electron-to-baryon ...

  7. Theoretical investigation of the electron capture and loss processes in the collisions of He2+ + Ne.

    Science.gov (United States)

    Hong, Xuhai; Wang, Feng; Jiao, Yalong; Su, Wenyong; Wang, Jianguo; Gou, Bingcong

    2013-08-28

    Based on the time-dependent density functional theory, a method is developed to study ion-atom collision dynamics, which self-consistently couples the quantum mechanical description of electron dynamics with the classical treatment of the ion motion. Employing real-time and real-space method, the coordinate space translation technique is introduced to allow one to focus on the region of target or projectile depending on the actual concerned process. The benchmark calculations are performed for the collisions of He(2+) + Ne, and the time evolution of electron density distribution is monitored, which provides interesting details of the interaction dynamics between the electrons and ion cores. The cross sections of single and many electron capture and loss have been calculated in the energy range of 1-1000 keV/amu, and the results show a good agreement with the available experiments over a wide range of impact energies.

  8. Proton-induced single electron capture on DNA/RNA bases.

    Science.gov (United States)

    Champion, C; Weck, P F; Lekadir, H; Galassi, M E; Fojón, O A; Abufager, P; Rivarola, R D; Hanssen, J

    2012-05-21

    In this work, we report total cross sections for the single electron capture process induced on DNA/RNA bases by high-energy protons. The calculations are performed within both the continuum distorted wave and the continuum distorted wave-eikonal initial state approximations. The biological targets are described within the framework of self-consistent methods based on the complete neglect of differential overlap model whose accuracy has first been checked for simpler bio-molecules such as water vapour. Furthermore, the multi-electronic problem investigated here is reduced to a mono-electronic one using a version of the independent electron approximation. Finally, the obtained theoretical predictions are confronted with the scarcely available experimental results.

  9. Studies of electron correlation effects in multicharged ion atom collisions involving double capture

    Energy Technology Data Exchange (ETDEWEB)

    Stolterfoht, N.; Sommer, K.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Meyer, F.W.

    1988-01-01

    We review measurements of L-Coster Kronig and Auger electron production in slow, multicharged collision systems to study electron correlation effects in the process of double electron capture. The n/sup /minus/3/ law was confirmed for the production of the Coster-Kronig configurations 1s/sup 2/2pn/ell/ (n greater than or equal to 6) in O/sup 6 +/ + He collisions. Enhancement of high angular momentum /ell/ in specific 1s/sup 2/2pn/ell/ configurations was observed by means of high-resolution measurements of the Coster-Kronig lines. The importance of electron correlation effects in couplings of potential energy curves leading to the 1s/sup 2/2pn/ell/ configurations is verified by means of Landau-Zener model calculations. 32 refs., 4 figs.

  10. Multiple capture investigated by coincident electron spectroscopy in X{sup 7+}+Ar, at 70 keV

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Universite Paul Sabatier, Toulouse (France). Lab. Collisions-Agregats-Reactivite

    1999-11-01

    The multiple electron capture in N{sup 7+} + Ar and F{sup 7+}(1s{sup 2}) + Ar systems is investigated at 70 keV with a new electron-recoil ion charge coincidence experiment. The whole electron energy range has been studied. Up to six electrons are found to be captured into autoionizing states. The recoil ion charge distribution associated with the emission of electrons is similar for both systems and found to be in good agreement with the prediction of Niehaus`s model roughly adapted to take into account autoionizing cascades. New findings for the coincident double and triple captures are briefly discussed. A capture of an inner L-shell electron of Ar into the K-shell of the projectile is also observed in N{sup 7+} + Ar collisions. (orig.) 10 refs.

  11. Double-electron capture in relativistic U{sup 92+} collisions at the ESR gas-jet target

    Energy Technology Data Exchange (ETDEWEB)

    Bednarz, G. E-mail: d.sierpowski@gsi.deufsierpo@if.uj.edu.pl; Sierpowski, D.; Stoehlker, Th.; Warczak, A.; Beyer, H.; Bosch, F.; Braeuning-Demian, A.; Braeuning, H.; Cai, X.; Gumberidze, A.; Hagmann, S.; Kozhuharov, C.; Liesen, D.; Ma, X.; Mokler, P.H.; Muthig, A.; Stachura, Z.; Toleikis, S

    2003-05-01

    Total cross-sections for radiative single- and double-electron capture are measured in collisions of fast highly charged ions with light target atoms. Cross-sections for non-correlated double capture are in accordance with theoretical predictions. No significant line structure at twice the single K-radiative electron capture (K-REC) photon energy was observed. Angular distributions single K-REC photons associated with single- and double-charge exchange exhibit the same pattern. The corresponding REC lines are almost by a factor of two broader for double-charge exchange than in the single capture case.

  12. Identification and measurement of chlorinated organic pesticides in water by electron-capture gas chromatography

    Science.gov (United States)

    Lamar, William L.; Goerlitz, Donald F.; Law, LeRoy M.

    1965-01-01

    Pesticides, in minute quantities, may affect the regimen of streams, and because they may concentrate in sediments, aquatic organisms, and edible aquatic foods, their detection and their measurement in the parts-per-trillion range are considered essential. In 1964 the U.S. Geological Survey at Menlo Park, Calif., began research on methods for monitoring pesticides in water. Two systems were selected--electron-capture gas chromatography and microcoulometric-titration gas chromatography. Studies on these systems are now in progress. This report provides current information on the development and application of an electron-capture gas chromatographic procedure. This method is a convenient and extremely sensitive procedure for the detection and measurement of organic pesticides having high electron affinities, notably the chlorinated organic pesticides. The electron-affinity detector is extremely sensitive to these substances but it is not as sensitive to many other compounds. By this method, the chlorinated organic pesticide may be determined on a sample of convenient size in concentrations as low as the parts-per-trillion range. To insure greater accuracy in the identifications, the pesticides reported were separated and identified by their retention times on two different types of gas chromatographic columns.

  13. Multiple electron capture from isolated protein poly-anions in collision with slow highly charged ions.

    Science.gov (United States)

    Milosavljević, A R; Rousseau, P; Domaracka, A; Huber, B A; Giuliani, A

    2017-08-02

    Collisions of 375 keV Xe(25+) ions with trapped mass/charge selected poly-anions of the cytochrome C protein (∼12.5 kDa) were studied by coupling a linear quadrupole ion trap with low-energy ion beam facility. Tandem mass spectra were recorded for the protein precursor charge states ranging from -9 to -17. The present work reports the first study of slow highly charged ion collisions with poly-anions. A high signal to noise ratio allowed the study of the intensity of single and multiple electron removal by a projectile, as well as associated neutral losses, as a function of the target charge state. Relative single and double electron detachment cross sections were found to increase with increasing charge state of the precursor anion. The experimental findings are supported by the calculations of the total electron capture cross sections, based on the classical over-the-barrier model, restricted to a simple uniformly charged linear protein structure and a near-end electron capture.

  14. Measurement of the solar neutrino capture rate with gallium metal, Part III

    CERN Document Server

    Abdurashitov, J N; Gorbachev, V V; Gurkina, P P; Ibragimova, T V; Kalikhov, A V; Khairnasov, N G; Knodel, T V; Mirmov, I N; Shikhin, A A; Veretenkin, E P; Yants, V E; Zatsepin, G T; Bowles, T J; Elliott, S R; Teasdale, W A; Nico, J S; Cleveland, B T; Wilkerson, J F

    2009-01-01

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. We give here the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keV of 65.4 (+3.1)(-3.0) (stat) (+2.6)(-2.8) (syst) SNU. The weighted average of the results of all three Ga solar neutrino experiments, SAGE, Gallex, and GNO, is now 66.1 +/- 3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced 37Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in...

  15. Measurement of the solar neutrino capture rate with gallium metal, part III

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Steven Ray [Los Alamos National Laboratory

    2008-01-01

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. In this article we present the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keY of 65.4{sup +3.1}{sub 3.0} (stat) {sup +2.6}{sub -2.8} (syst) SNU. The weighted average of the results of all three Ga solar neUlrino experiments, SAGE, Gallex, and GNO, is now 66.1 {+-} 3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced {sup 37}Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior {sup 51}Cr neutrino-source experiments with Ga, is 0.88 {+-} 0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in {sup 71}Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63--67 SNU with an uncertainly of about 5%, in good agreement with experiment. We derive the current value of the pp neutrino flux produced in the Sun to be {phi}{sup {circle_dot}}{sub pp} = (6.1 {+-} 0.8) x 10{sup 10}/(cm{sup 2} s), which agrees well with the flux predicted by the standard solar model. Finally, we make several tests and show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

  16. Electron Beam Analysis of Micrometeoroids Captured in Aerogel as Stardust Analogues

    Science.gov (United States)

    Graham, G. A.; Sheffield-Parker, J.; Bradley, P.; Kearsley, A. T.; Dai, Z. R.; Mayo, S. C.; Teslich, N.; Snead, C.; Westphal, A. J.; Ishii, H.

    2005-01-01

    In January 2004, NASA s Stardust spacecraft passed through the tail of Comet 81P/Wild-2. The on-board dust flux monitor instrument indicated that numerous micro- and nano-meter sized cometary dust particles were captured by the dedicated silica aerogel capture cell. The collected cometary particles will be returned to Earth in January 2006. Current Stardust analogues are: (i) Light-gas-gun accelerated individual mineral grains and carbonaceous meteoritic material in aerogels at the Stardust encounter velocity ca.approximately 6 kilometers per second. (ii) Aerogels exposed in low-Earth orbit (LEO) containing preserved cosmic dust grains. Studies of these impacts offer insight into the potential state of the captured cometary dust by Stardust and the suitability of various analytical techniques. A number of papers have discussed the application of sophisticated synchrotron analytical techniques to analyze Stardust particles. Yet much of the understanding gained on the composition and mineralogy of interplanetary dust particles (IDPs) has come from electron microscopy studies. Here we discuss the application of scanning electron microscopy (SEM) for Stardust during the preliminary phase of post-return investigations.

  17. Determining astrophysical three-body radiative capture reaction rates from inclusive Coulomb break-up measurements

    CERN Document Server

    Casal, J; Arias, J M; Gómez-Camacho, J

    2016-01-01

    A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly-bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of $B(E1)$ distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to $^{11}$Li ($^{9}$Li+n+n) and $^6$He ($^{4}$He+n+n) three-body systems for which some data exist.

  18. Determining astrophysical three-body radiative capture reaction rates from inclusive Coulomb break-up measurements

    Science.gov (United States)

    Casal, J.; Rodríguez-Gallardo, M.; Arias, J. M.; Gómez-Camacho, J.

    2016-04-01

    A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of B (E 1 ) distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to 11Li (9Li+n +n ) and 6He (4He+n +n ) three-body systems for which some data exist.

  19. Search for two-neutrino double electron capture on $^{124}$Xe with the XMASS-I detector

    CERN Document Server

    Abe, K; Ichimura, K; Kishimoto, Y; Kobayashi, K; Kobayashi, M; Moriyama, S; Nakagawa, K; Nakahata, M; Norita, T; Ogawa, H; Sekiya, H; Takachio, O; Takeda, A; Yamashita, M; Yang, B S; Kim, N Y; Kim, Y D; Tasaka, S; Liu, J; Martens, K; Suzuki, Y; Fujita, R; Hosokawa, K; Miuchi, K; Ohnishi, Y; Oka, N; Takeuchi, Y; Kim, Y H; Lee, J S; Lee, K B; Lee, M K; Fukuda, Y; Itow, Y; Kegasa, R; Masuda, K; Takiya, H; Uchida, H; Nishijima, K; Fujii, K; Murayama, I; Nakamura, S

    2015-01-01

    Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on $^{124}$Xe is performed using 165.9 days of data collected with the XMASS-I detector. No significant excess above background was observed and we set a lower limit on the half-life as $4.7 \\times 10^{21}$ years at 90% confidence level.

  20. Determination of the Astrophysical S(E) Factors or Rates for Radiative Capture Reaction with One Nucleon Transfer Reaction%Determination of the Astrophysical S(E) Factors or Rates for Radiative Capture Reaction with One Nucleon Transfer Reaction

    Institute of Scientific and Technical Information of China (English)

    李志宏; 郭冰; 李云居; 苏俊; 李二涛; 白希祥; 王友宝; 曾晟; 王宝祥; 颜胜权; 李志常; 刘建成; 连钢; 金孙均; 刘鑫; 柳卫平

    2012-01-01

    The radiative capture reaction plays an important role in nuclear astrophysics. We have indirectly measured the astrophysical S(E) factors for some proton capture reactions and reaction rates for several neutron capture reactions with one nucleon transfer reactions at HI-13 tandem accelerator in recent years. Some of them are compiled into IAEA EXFOR database and JINA REACLIB project, and used in the network calculations of Big Bang nucleosynthesis and type-I X-ray bursts.

  1. Vibrationally Resolved Electron Transfer Rates in Solution

    Science.gov (United States)

    Spears, Kenneth G.

    2002-03-01

    We have re-examined our earlier report of electron transfer in the [Co(Cp)_2|V(CO)_6] radical-pair using ultrafast infrared transient absorption spectroscopy in room temperature solutions. The radical-pair is created from the [Co(Cp)_2^+|V(CO)_6^-] ion-pair by ultrafast visible charge-transfer excitation. Transient absorption experiments with ps time constants. A small ET component with a 75 ps time constant is due to some separation and reformation of the radical-pairs. Transient absorption experiments monitoring the recovery of the ion-pair state shows that both fast components are due to ET rather than some other vibrational relaxation (VR) process in the radical state. We analyze the visible charge-transfer band and assign the two fast ET decay times to two ion-pair contact geometries with absorption origins different by about 1250 ± 350 cm-1. For excitation at 800 and 700 nm the 700 fs ET lifetime depends on the vibrational quantum state of the nontotally symmetric CO stretch in the V(CO)6 radical, where the lifetime decreases by 10% for the first vibrational quantum and 45% for the second quantum. There is no quantum effect for the second ion-pair geometry with a 5 ps ET lifetime. Standard ET rate models cannot explain the rate dependence upon vibrational quantum state for a nontotally symmetric vibration, and it may arise from a breakdown of the Condon approximation. We also report rates for IVR of CO stretching modes and for VR of low frequency vibrations. At excitation wavelengths of 620 and 555 nm there is sufficient internal vibrational energy in low-frequency vibrations to cause geometric inter-conversion between energetically similar Jahn-Teller geometries in the V(CO)6 radical. This process creates a 200 fs rise time for the V(CO)6 radical species to assume a stable geometry, which requires VR of low frequency vibrations to the solvent. These results demonstrate that earlier ET measurements from our group on the same molecule had insufficient time

  2. Electronic data capture and DICOM data management in multi-center clinical trials

    Science.gov (United States)

    Haak, Daniel; Page, Charles-E.; Deserno, Thomas M.

    2016-03-01

    Providing eligibility, efficacy and security evaluation by quantitative and qualitative disease findings, medical imaging has become increasingly important in clinical trials. Here, subject's data is today captured in electronic case reports forms (eCRFs), which are offered by electronic data capture (EDC) systems. However, integration of subject's medical image data into eCRFs is insufficiently supported. Neither integration of subject's digital imaging and communications in medicine (DICOM) data, nor communication with picture archiving and communication systems (PACS), is possible. This aggravates the workflow of the study personnel, in special regarding studies with distributed data capture in multiple sites. Hence, in this work, a system architecture is presented, which connects an EDC system, a PACS and a DICOM viewer via the web access to DICOM objects (WADO) protocol. The architecture is implemented using the open source tools OpenClinica, DCM4CHEE and Weasis. The eCRF forms the primary endpoint for the study personnel, where subject's image data is stored and retrieved. Background communication with the PACS is completely hidden for the users. Data privacy and consistency is ensured by automatic de-identification and re-labelling of DICOM data with context information (e.g. study and subject identifiers), respectively. The system is exemplarily demonstrated in a clinical trial, where computer tomography (CT) data is de-centrally captured from the subjects and centrally read by a chief radiologists to decide on inclusion of the subjects in the trial. Errors, latency and costs in the EDC workflow are reduced, while, a research database is implicitly built up in the background.

  3. Electron Capture in Collisions of Slow Highly Charged Ions with an Atom and a Molecule: Processes and Fragmentation Dynamics

    Directory of Open Access Journals (Sweden)

    Xavier Husson

    2002-03-01

    Full Text Available Abstract : Processes involved in slow collisions between highly charged ions (HCI and neutral targets are presented. First, the mechanisms responsible for double electron capture are discussed. We show that, while the electron-nucleus interaction is expected to be dominant at projectile velocities of about 0.5 a.u., the electron-electron interaction plays a decisive role during the collision and gains importance when the projectile velocity decreases. This interaction has also to be invoked in the capture of core electrons by HCI. Finally, the molecular fragmentation of H2 following the impact of HCI is studied.

  4. Polarized [sup 3]He ion source based on polarized electron capture

    Energy Technology Data Exchange (ETDEWEB)

    Ohshima, Takashi (Osaka Univ., Toyonaka (Japan). Faculty of Science)

    1993-11-01

    The [sup 3]He[sup +] ions which are formed by [sup 3]He[sup 2+] ions capturing the polarized electrons of the sodium atoms polarized by optical pumping become nuclear polarized beam, as electron polarization shifts to nuclei by ultrafine interaction. When the current of [sup 3]He[sup 2+] ions was 2 e[mu]A, and the degree of polarization of sodium atoms was 0.30[+-]0.05, the [sup 3]He[sup +] beam of nuclear polarization degree 0.0415[+-]0.0061 and beam current 40 nA was obtained. By carrying out the improvement such as the increase of the degree of polarization of sodium or the current of [sup 3]He[sup 2+], it can be expected to form the polarized beam of current more than 10 [mu]A and degree of polarization close to 30%. The polarization experiment carried out so far was mostly on protons and deuterons, and as for [sup 3]He, there was only one polarization experiment. In Research Center for Nuclear Physics, Osaka University, the [sup 3]He beam up to 530 MeV can be obtained by using the ring cyclotron, therefore, it was decided to develop the polarized [sup 3]He ion source using polarized electron capture. The principle of polarization formation, the experimental equipment consisting of ECR ion source, polarized Na target and [sup 3]He nuclear polarization measuring part, and the experimental results are reported. (K.I.).

  5. Single electron capture measurements in collisions of K{sup +} on N{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Alarcón, F.B. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Fuentes, B.E., E-mail: beatriz.fuentes@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, 04510 México D.F. (Mexico); Martínez, H. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Yousif, F.B. [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Av. Universidad #1000, Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico)

    2014-08-01

    Absolute total charge transfer cross sections have been measured for K{sup +}–N{sub 2} collisions, at impact energies between 1.0 and 3.5 keV. The charge transfer cross sections show a monotonic increasing behaviour as a function of the incident energy. Agreement with other groups is observed as the present measurements extend to lower energies. A semi-empirical calculation shows a similar behaviour to the present data with respect to the electron capture cross sections as a function of energy.

  6. Determination of fluoxetine and norfluoxetine in plasma by gas chromatography with electron-capture detection

    Energy Technology Data Exchange (ETDEWEB)

    Nash, J.F.; Bopp, R.J.; Carmichael, R.H.; Farid, K.Z.; Lemberger, L.

    1982-10-01

    This gas-chromatographic method for assay of fluoxetine and norfluoxetine in human plasma involves extraction of the drugs and use of a /sup 63/Ni electron-capture detector. The linear range of detection is 25 to 800 micrograms/L for each drug. Overall precision (CV) in the concentration range of 10 to 100 micrograms/L for both drugs was approximately 10%. Accuracy (relative error) in the same concentration range was approximately +10%. None of the commonly prescribed antidepressants or tranquilizers that we tested interfere with the assay.

  7. Determination of desmethyldiazepam in plasma by electron-capture GLC: application to pharmacokinetic studies of clorazepate.

    Science.gov (United States)

    Greenblatt, D J

    1978-03-01

    Plasma desmethyldiazepam concentrations were quantitated by a rapid and sensitive technique using electron-capture GLC. Following addition of diazepam as the internal standard, plasma is extracted at physiological pH into benzene-isoamyl alcohol. The extract is evaporated to dryness and reconstituted with toluene-isoamyl alcohol prior to chromatography. Both diazepam and desmethyldiazepam are quantitatively extracted. The variation of identical samples is 5%, and the sensitivity is 5 ng of desmethyldiazepam/ml of original sample. The method is applicable to pharmacokinetic studies of clorazepate, a benzodiazepine derivative transformed to desmethyldiazepam prior to absorption.

  8. Search for two-neutrino double electron capture on 124Xe with the XMASS-I detector

    Directory of Open Access Journals (Sweden)

    K. Abe

    2016-08-01

    Full Text Available Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on 124Xe is performed using 165.9 days of data collected with the XMASS-I liquid xenon detector. No significant excess above background was observed and we set a lower limit on the half-life as 4.7×1021 years at 90% confidence level. The obtained limit has ruled out parts of some theoretical expectations. We obtain a lower limit on the 126Xe two-neutrino double electron capture half-life of 4.3×1021 years at 90% confidence level as well.

  9. Search for two-neutrino double electron capture on 124Xe with the XMASS-I detector

    Science.gov (United States)

    Abe, K.; Hiraide, K.; Ichimura, K.; Kishimoto, Y.; Kobayashi, K.; Kobayashi, M.; Moriyama, S.; Nakagawa, K.; Nakahata, M.; Norita, T.; Ogawa, H.; Sekiya, H.; Takachio, O.; Takeda, A.; Yamashita, M.; Yang, B. S.; Kim, N. Y.; Kim, Y. D.; Tasaka, S.; Liu, J.; Martens, K.; Suzuki, Y.; Fujita, R.; Hosokawa, K.; Miuchi, K.; Oka, N.; Onishi, Y.; Takeuchi, Y.; Kim, Y. H.; Lee, J. S.; Lee, K. B.; Lee, M. K.; Fukuda, Y.; Itow, Y.; Kegasa, R.; Kobayashi, K.; Masuda, K.; Takiya, H.; Uchida, H.; Nishijima, K.; Fujii, K.; Murayama, I.; Nakamura, S.

    2016-08-01

    Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on 124Xe is performed using 165.9 days of data collected with the XMASS-I liquid xenon detector. No significant excess above background was observed and we set a lower limit on the half-life as 4.7 ×1021 years at 90% confidence level. The obtained limit has ruled out parts of some theoretical expectations. We obtain a lower limit on the 126Xe two-neutrino double electron capture half-life of 4.3 ×1021 years at 90% confidence level as well.

  10. Simultaneous use of mark-recapture and radiotelemetry to estimate survival, movement, and capture rates

    Science.gov (United States)

    Powell, L.A.; Conroy, M.J.; Hines, J.E.; Nichols, J.D.; Krementz, D.G.

    2000-01-01

    Biologists often estimate separate survival and movement rates from radio-telemetry and mark-recapture data from the same study population. We describe a method for combining these data types in a single model to obtain joint, potentially less biased estimates of survival and movement that use all available data. We furnish an example using wood thrushes (Hylocichla mustelina) captured at the Piedmont National Wildlife Refuge in central Georgia in 1996. The model structure allows estimation of survival and capture probabilities, as well as estimation of movements away from and into the study area. In addition, the model structure provides many possibilities for hypothesis testing. Using the combined model structure, we estimated that wood thrush weekly survival was 0.989 ? 0.007 ( ?SE). Survival rates of banded and radio-marked individuals were not different (alpha hat [S_radioed, ~ S_banded]=log [S hat _radioed/ S hat _banded]=0.0239 ? 0.0435). Fidelity rates (weekly probability of remaining in a stratum) did not differ between geographic strata (psi hat=0.911 ? 0.020; alpha hat [psi11, psi22]=0.0161 ? 0.047), and recapture rates ( = 0.097 ? 0.016) banded and radio-marked individuals were not different (alpha hat [p_radioed, p_banded]=0.145 ? 0.655). Combining these data types in a common model resulted in more precise estimates of movement and recapture rates than separate estimation, but ability to detect stratum or mark-specific differences in parameters was week. We conducted simulation trials to investigate the effects of varying study designs on parameter accuracy and statistical power to detect important differences. Parameter accuracy was high (relative bias [RBIAS] inference from this model, study designs should seek a minimum of 25 animals of each marking type observed (marked or observed via telemetry) in each time period and geographic stratum.

  11. Effects of Purge-Flow Rate on Microbubble Capture in Radial Arterial-Line Filters.

    Science.gov (United States)

    Herbst, Daniel P

    2016-09-01

    The process of microbubble filtration from blood is complex and highly dependent on the forces of flow and buoyancy. To protect the patient from air emboli, arterial-line filters commonly use a micropore screen, a large volume housing with purpose-built shape, and a purge port to trap, separate, and remove circulating microbubbles. Although it has been proposed that an insufficient buoyancy force renders the purge port ineffective at removing microbubbles smaller than 500 μm, this research attempts to investigate the purge flow of an arterial-line filter to better understand the microbubble removal function in a typical radial filter design. As its primary objective, the study aims to determine the effect of purge-flow rate on bubble capture using air bolus injections from a syringe pump with 22-gauge needle and Doppler ultrasound bubble detection. The measureable bubble size generated in the test circuit ranged between 30 and 500 μm, while purge flow was varied between .1 and .5 L/min for testing. Statistical analysis of the test data was handled using a repeated measures design with significance set at p purge flows yielded higher bubble counts, but the effect of purge-flow rate on bubble capture decreased as bubble size increased. Results also showed that purge flow from the test filter was capable of capturing all bubble sizes being generated over the entire flow range tested, and confirms utility of the purge port in removing microbubbles smaller than 500 μm. By analyzing bubble counts in the purge flow of a typical radial-filter design, this study demonstrates that currently available micropore filter technology is capable of removing the size range of bubbles that commonly pass through modern pump-oxygenator systems and should continue to be considered during extracorporeal circulation as a measure to improve patient safety.

  12. Electron correlations in single-electron capture into any state of fast projectiles from heliumlike atomic systems

    Science.gov (United States)

    Mančev, Ivan; Milojević, Nenad; Belkić, Dževad

    2013-11-01

    State-selective and total single-electron capture cross sections in fast collisions of a bare projectile with a heliumlike target are examined in the four-body formalism. A special emphasis is given to a proper inclusion of dynamic electron-electron correlation effects. For this purpose, the post form of the four-body boundary-corrected first Born approximation (CB1-4B) is utilized. With regard to our related previous study, where the prior version has been considered, in the present work an extensive analytical study of the post-transition amplitude for electron capture into the arbitrary final states nflfmf of the projectile is carried out. The post-transition amplitude for single charge exchange encompassing symmetric and asymmetric collisions is derived in terms of five-dimensional integrals over real variables. The dielectronic interaction V12=1/r12≡1/|r⃗1-r⃗2| explicitly appears in the perturbation potential Vf of the post-transition probability amplitude Tif+, such that the CB1-4B method can provide information about the relative significance of the dynamic interelectron correlation in the collisions under study. An illustrative computation is performed involving state-selective and total single capture cross sections for the p-He collisions at intermediate and high impact energies. The so-called post-prior discrepancy, which plagues almost all the existing distorted wave approximations, is presently shown to be practically nonexistent in the CB1-4B method. The validity of our findings is critically assessed in comparisons with the available experimental data for both state-selective and total cross sections summed over all the discrete energy levels of the hydrogenlike atom formed with the projectile. Overall, excellent performance of the CB1-4B method is recorded, thus robustly establishing this formalism as the leading first-order description of high-energy single charge exchange, which is a collision of paramount theoretical and practical

  13. Atmospheric measurements of carbonyl sulfide, dimethyl sulfide, and carbon disulfide using the electron capture sulfur detector

    Science.gov (United States)

    Johnson, James E.; Bates, Timothy S.

    1993-01-01

    Measurements of atmospheric dimethyl sulfide (DMS), carbonyl sulfide (COS), and carbon disulfide (CS2) were conducted over the Atlantic Ocean on board the NASA Electra aircraft during the Chemical Instrumentation Test and Evaluation (CITE 3) project using the electron capture sulfur detector (ECD-S). The system employed cryogenic preconcentration of air samples, gas chromatographic separation, catalytic fluorination, and electron capture detection. Samples collected for DMS analysis were scrubbed of oxidants with NaOH impregnated glass fiber filters to preconcentration. The detection limits (DL) of the system for COS, DMS, and CS2 were 5, 5, and 2 ppt, respectively. COS concentrations ranged from 404 to 603 ppt with a mean of 489 ppt for measurements over the North Atlantic Ocean (31 deg N to 41 deg N), and from 395 to 437 ppt with a mean of 419 ppt for measurements over the Tropical Atlantic Ocean (11 deg S to 2 deg N). DMS concentrations in the lower marine boundary layer, below 600-m altitude, ranged from below DL to 150 ppt from flights over the North Atlantic, and from 9 to 104 ppt over the Tropical Atlantic. CS2 concentrations ranged from below DL to 29 ppt over the North Atlantic. Almost all CS2 measurements over the Tropical Atlantic were below DL.

  14. Identification and systematical studies of the electron-capture delayed fission (ECDF) in the lead region

    CERN Multimedia

    Pauwels, D B; Lane, J

    2008-01-01

    In our recent experiment (March 2007) at the velocity filter SHIP(GSI) we observed the electron-capture delayed fission of the odd-odd isotope $^{194}$At. This is the first unambiguous identification of this phenomenon in the very neutron-deficient nuclei in the vicinity of the proton shell closure at Z=82. In addition, the total kinetic energy (TKE) for the daughter nuclide $^{194}$Po was measured, despite the fact that this isotope does not decay via spontaneous fission. Semi-empirical analysis of the electron-capture Q$_{EC}$ values and fission barriers B$_{f}$ shows that a relatively broad island of ECDF must exist in this region of the Nuclide Chart, with some of the nuclei having unusually high ECDF probabilities. Therefore, this Proposal is intended to initiate the systematic identification and study of $\\beta$-delayed fission at ISOLDE in the very neutron-deficient lead region. Our aim is to provide unique low-energy fission data (e.g. probabilities, TKE release, fission barriers and their isospin dep...

  15. Search for Oscillation of the Electron-Capture Decay Probability of Pm-142

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, Paul A; Vetter, Paul; Clark, Roderick; Dvorak, Jan; Freedman, Stuart; Gregorich, Kenneth; Jeppesen, Henrik; Mittelberger, Daniel; Wiedeking, Mathis

    2008-07-03

    We have searched for time modulation of the electron capture decay probability of 142Pm in an attempt to confirm a recent claim from a group at the Gesellschaft fur Schwerionenforschung (GSI). We produced 142Pm via the 124Sn(23Na, 5n)142Pm reaction at the Berkeley 88-Inch Cyclotron with a bombardment time short compared to the reported modulation period. Isotope selection by the Berkeley Gas-filled Separator is followed by implantation and a long period of monitoring the 142Nd K alpha x-rays from the daughter. The decay time spectrum of the x-rays is well-described by a simple exponential and the measured half-life of 40.68(53) seconds is consistent with the accepted value. We observed no oscillatory modulation at the proposed frequency at a level 31 times smaller than that reported by Litvinov (Phys. Lett. B 664 (2008) 162). A literature search for previous experiments that might have been sensitive to the reported modulation uncovered another example in 142Eu electron-capture decay. A reanalysis of the published data shows no oscillatory behavior.

  16. Electron Capture from Linear Stark Rydberg States above the Matching Velocity

    Science.gov (United States)

    Ciocca, M.; Creasey, C.; MacAdam, K. B.

    1998-05-01

    The relative cross section for electron capture by singly charged ions from linear Stark Rydberg states of Na has been measured, both as a function of the angle of impact and of projectile velocity. The target, the topmost state of the n = 24 Stark manifold, was prepared by two-step laser excitation from the Na ground state, via 3p_3/2, in an electric field F_Stark= 160 V/cm. By means of a device perfected in our laboratory (the "Stark Barrel"), we aligned the target by adiabatically switching the electric field, after excitation, down to a preset low value and a desired direction in the plane determined by the ion and Na beams. Thermionic emission ion sources of Li and Na were operated at accelerating voltages 400-2000 V to allow study of electron capture in the reduced velocity range v = 1.0 - 2.5. This augments an earlier study by Homan footnote D. M. Homan, Ph. D. Dissertation, University of Kentucky 1997, unpublished. at lower velocities.

  17. Multiple electron capture from thin C-foils into 46 MeV/u U{sup 91+}

    Energy Technology Data Exchange (ETDEWEB)

    Braeuning, H. E-mail: harald.braeuning@strz.uni-giessen.de; Braeuning-Demian, A.; Bednarz, G.; Bosch, F.; Cai, X.; Cohen, C.; Dauvergne, D.; Gumberidze, A.; Kirsch, R.; Kozhuharov, C.; Liesen, D.; Mokler, P.H.; Rozet, J.-P.; Stachura, Z.; Stoehlker, Th.; Terasawa, M.; Toleikis, S.; Warczak, A

    2003-05-01

    Absolute yields for multiple electron capture as well as projectile ionization have been measured for 46 MeV/u U{sup 91+} ions traversing thin carbon foils with different surface topologies. Multiple electron capture yields vary strongly, depending on the target manufacturer. The samples including the one with the smoothest surface show a deviation of the yield from the expected scaling based on subsequent single capture for decreasing target thickness. This indicates a strong contribution of the surface, whose nature cannot be identified by the current data.

  18. Measurements of structural material capture to uranium-235 fission rate ratios in an intermediate spectrum assembly

    Energy Technology Data Exchange (ETDEWEB)

    Azzoni, P.; Benzi, V.; Chiodi, P.L.; Giuliani, C.; Guardini, S.; Marrasi, R.; Salomoni, A.; Tassan, S.

    1980-10-01

    Experimental determinations of capture rates of structural materials used in fast breeder reactors, such as iron, chromium, nickel, and stainless steel, normalized to the /sup 235/U fission rate, were performed. The aim of these experiments was to check structural material multigroup cross-section libraries in the 1- to 100-keV range, where substantial discrepancies among various cross-section evaluations are not yet resolved. The experiments were carried out in an ARGONAUTtype RB-2 reactor, using the Null Reactivity Oscillation method, on test media composed of quasi-homogeneous loose particle mixtures. Comparisons were carried out with corresponding calculated values, showing a trend of these values to overestimate the measured quantities. These results are not in disagreement with the indications of recent /sup 235/U cross-section measurements as far as the sigma /SUB c/ /sigma /SUB f/ of /sup 235/U is concerned.

  19. Rate-dependent interface capture beyond the coffee-ring effect

    Science.gov (United States)

    Li, Yanan; Yang, Qiang; Li, Mingzhu; Song, Yanlin

    2016-04-01

    The mechanism of droplet drying is a widely concerned fundamental issue since controlling the deposition morphology of droplet has significant influence on printing, biology pattern, self-assembling and other solution-based devices fabrication. Here we reveal a striking different kinetics-controlled deposition regime beyond the ubiquitous coffee-ring effect that suspended particles tend to kinetically accumulate at the air-liquid interface and deposit uniformly. As the interface shrinkage rate exceeds the particle average diffusion rate, particles in vertical evaporation flow will be captured by the descending surface, producing surface particle jam and forming viscous quasi-solid layer, which dramatically prevents the trapped particles from being transported to drop edge and results in uniform deposition. This simple, robust drying regime will provide a versatile strategy to control the droplet deposition morphology, and a novel direction of interface assembling for fabricating superlattices and high quality photonic crystal patterns.

  20. Hydrogen rearrangement to and from radical z fragments in electron capture dissociation of peptides

    DEFF Research Database (Denmark)

    Savitski, Mikhail M; Kjeldsen, Frank; Nielsen, Michael L

    2007-01-01

    capture dissociation (ECD), including previously unreported double H. losses. Consistent with the radical character of H. abstraction, the residue determining the formation rate of z' = z. + H. species is found to be the N-terminal residue in z. species. The size of the complementary c(m)' fragment turned...... out to be another important factor, with z' species dominating over z. ions for m carbon groups of residues composing the c' species, with Gln and His in the c' fragment promoting H. donation and Asp and Ala...

  1. A Novel Feature Extraction Approach Using Window Function Capturing and QPSO-SVM for Enhancing Electronic Nose Performance

    Directory of Open Access Journals (Sweden)

    Xiuzhen Guo

    2015-06-01

    Full Text Available In this paper, a novel feature extraction approach which can be referred to as moving window function capturing (MWFC has been proposed to analyze signals of an electronic nose (E-nose used for detecting types of infectious pathogens in rat wounds. Meanwhile, a quantum-behaved particle swarm optimization (QPSO algorithm is implemented in conjunction with support vector machine (SVM for realizing a synchronization optimization of the sensor array and SVM model parameters. The results prove the efficacy of the proposed method for E-nose feature extraction, which can lead to a higher classification accuracy rate compared to other established techniques. Meanwhile it is interesting to note that different classification results can be obtained by changing the types, widths or positions of windows. By selecting the optimum window function for the sensor response, the performance of an E-nose can be enhanced.

  2. A Novel Feature Extraction Approach Using Window Function Capturing and QPSO-SVM for Enhancing Electronic Nose Performance.

    Science.gov (United States)

    Guo, Xiuzhen; Peng, Chao; Zhang, Songlin; Yan, Jia; Duan, Shukai; Wang, Lidan; Jia, Pengfei; Tian, Fengchun

    2015-06-29

    In this paper, a novel feature extraction approach which can be referred to as moving window function capturing (MWFC) has been proposed to analyze signals of an electronic nose (E-nose) used for detecting types of infectious pathogens in rat wounds. Meanwhile, a quantum-behaved particle swarm optimization (QPSO) algorithm is implemented in conjunction with support vector machine (SVM) for realizing a synchronization optimization of the sensor array and SVM model parameters. The results prove the efficacy of the proposed method for E-nose feature extraction, which can lead to a higher classification accuracy rate compared to other established techniques. Meanwhile it is interesting to note that different classification results can be obtained by changing the types, widths or positions of windows. By selecting the optimum window function for the sensor response, the performance of an E-nose can be enhanced.

  3. Longitudinal assessment of pain outcomes in the clinical setting: development of the "APOLO" electronic data capture system.

    Science.gov (United States)

    Hassett, Afton L; Wasserman, Ronald; Goesling, Jenna; Rakovitis, Kevin; Shi, Baorong; Brummett, Chad M

    2012-01-01

    Data to fully evaluate the effectiveness of many commonly used interventions in the clinical pain management setting are inadequate. Clinical data collected for patient management often are not based on validated instruments, and this impedes the ability to conduct longitudinal research. To address these needs, modified patient intake and return visit forms were established and the Assessment of Pain Outcomes Longitudinal Electronic Data Capture system was developed. Data collection has been underway since November 22, 2010. As of December 7, 2011, 951 New Patient and 688 Return Visit forms had been entered. The forms have been well received, with less than 6.5% failing to complete at least 90% of the data requested. Accuracy of data entry is excellent, with an error rate of 1 in 11,250 potential data points. Data output converts easily to standard statistical programs. The creation of a pain outcomes database using validated measures and clinically relevant data is feasible.

  4. COINCIDENCES BETWEEN ELECTRONS AND TARGET IONS TO IDENTIFY CAPTURE CHANNELS IN COLLISIONS OF MULTIPLY CHARGED IONS ON GAS TARGETS

    NARCIS (Netherlands)

    POSTHUMUS, JH; MORGENSTERN, R

    1992-01-01

    We have investigated multielectron capture processes in collisions of Ar9+ on Ar by measuring the resulting Auger electrons in coincidence with charge-state-analyzed target ions. In this way it was possible to reconstruct partial electron energy spectra, each corresponding to a particular number of

  5. The effect of capturing the correct turbulence dissipation rate in BHR

    Energy Technology Data Exchange (ETDEWEB)

    Schwarzkopf, John Dennis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ristorcelli, Raymond [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-16

    In this manuscript, we discuss the shortcoming of a quasi-equilibrium assumption made in the BHR closure model. Turbulence closure models generally assume fully developed turbulence, which is not applicable to 1) non-equilibrium turbulence (e.g. change in mean pressure gradient) or 2) laminar-turbulence transition flows. Based on DNS data, we show that the current BHR dissipation equation [modeled based on the fully developed turbulence phenomenology] does not capture important features of nonequilibrium flows. To demonstrate our thesis, we use the BHR equations to predict a non-equilibrium flow both with the BHR dissipation and the dissipation from DNS. We find that the prediction can be substantially improved, both qualitatively and quantitatively, with the correct dissipation rate. We conclude that a new set of nonequilibrium phenomenological assumptions must be used to develop a new model equation for the dissipation to accurately predict the turbulence time scale used by other models.

  6. Capturing buried defects in metal interconnections with electron beam inspection system

    Science.gov (United States)

    Xiao, Hong; Jiang, Ximan; Trease, David; Van Riet, Mike; Ramprasad, Shishir; Bhatia, Anadi; Lefebvre, Pierre; Bastard, David; Moreau, Olivier; Maher, Chris; MacDonald, Paul; Campochiaro, Cecelia

    2013-04-01

    In this paper we present a novel mode of electron beam inspection (EBI), entitled super wide optics (SWO) mode, which can effectively detect buried defects in tungsten (W) plugs and copper (Cu) wires. These defects are defects of interest (DOI) to integrated circuit (IC) manufacturers because they are not detectable in optical inspection, voltage contrast (VC) mode EBI or physical mode EBI. We used engineering systems to study two samples, a tungsten chemical mechanical polish (CMP) wafer and a copper CMP wafer with a silicon carbon nitride (SiCN) cap layer. EBI with our novel SWO mode was found to capture many dark defects on these two wafers. Furthermore, defect review with all three EBI modes found some of these dark defects were unique to SWO mode. For verification, physical failure analysis was performed on some SWO-unique DOI. The cross-sectional scanning electron microscope (SEM) images and transmission electron microscope (TEM) images confirmed that the unique DOI were buried voids in W-plugs and copper wire thinning caused by either buried particles or buried particle induced metal trench under-etch. These DOI can significantly increase the resistance of metal interconnects of IC chip and affect the chip yield. This new EBI mode can provide an in-line monitoring solution for these DOI, which does not exist before this study.

  7. Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe.

    Science.gov (United States)

    Zhang, C J; Hua, J F; Xu, X L; Li, F; Pai, C-H; Wan, Y; Wu, Y P; Gu, Y Q; Mori, W B; Joshi, C; Lu, W

    2016-07-11

    A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.

  8. Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe

    Science.gov (United States)

    Zhang, C. J.; Hua, J. F.; Xu, X. L.; Li, F.; Pai, C.-H.; Wan, Y.; Wu, Y. P.; Gu, Y. Q.; Mori, W. B.; Joshi, C.; Lu, W.

    2016-07-01

    A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.

  9. Double lepton pair production with electron capture in relativistic heavy--ion collisions

    CERN Document Server

    Artemyev, A N; Surzhykov, A

    2014-01-01

    We present a theoretical study of a double lepton pair production in ultra--relativistic collision between two bare ions. Special emphasis is placed to processes in which creation of (at least one) $e^+ e^-$ pair is accompanied by the capture of an electron into a bound ionic state. To evaluate the probability and cross section of these processes we employ two approaches based on (i) the first--order perturbation theory and multipole expansion of Dirac wavefunctions, and (ii) the equivalent photon approximation. With the help of such approaches, detailed calculations are made for the creation of two bound--free $e^+ e^-$ pairs as well as of bound--free $e^+ e^-$ and free--free $\\mu^+ \\mu^-$ pairs in collisions of bare lead ions Pb$^{82+}$. The results of the calculations indicate that observation of the double lepton processes may become feasible at the LHC facility.

  10. Monitoring compliance with transfusion guidelines in hospital departments by electronic data capture

    DEFF Research Database (Denmark)

    Norgaard, Astrid; De Lichtenberg, Trine Honnens; Nielsen, Jens

    2014-01-01

    -transfusion haemoglobin levels at the departmental level. In a tertiary care hospital, no such data were produced before this study. Our aim was to establish a Patient Blood Management database based on electronic data capture in order to monitor compliance with transfusion guidelines at departmental and hospital levels......BACKGROUND: The practice of transfusing red blood cells is still liberal in some centres suggesting a lack of compliance with guidelines recommending transfusion of red blood cells at haemoglobin levels of 6-8 g/dL in the non-bleeding patient. Few databases provide ongoing feedback of data on pre....... MATERIALS AND METHODS: Hospital data on admissions, diagnoses and surgical procedures were used to define the populations of patients. Data on haemoglobin measurements and red blood cell transfusions were used to calculate pre-transfusion haemoglobin, percentage of transfused patients and transfusion...

  11. The Knowledge Program: an innovative, comprehensive electronic data capture system and warehouse.

    Science.gov (United States)

    Katzan, Irene; Speck, Micheal; Dopler, Chris; Urchek, John; Bielawski, Kay; Dunphy, Cheryl; Jehi, Lara; Bae, Charles; Parchman, Alandra

    2011-01-01

    Data contained in the electronic health record (EHR) present a tremendous opportunity to improve quality-of-care and enhance research capabilities. However, the EHR is not structured to provide data for such purposes: most clinical information is entered as free text and content varies substantially between providers. Discrete information on patients' functional status is typically not collected. Data extraction tools are often unavailable. We have developed the Knowledge Program (KP), a comprehensive initiative to improve the collection of discrete clinical information into the EHR and the retrievability of data for use in research, quality, and patient care. A distinct feature of the KP is the systematic collection of patient-reported outcomes, which is captured discretely, allowing more refined analyses of care outcomes. The KP capitalizes on features of the Epic EHR and utilizes an external IT infrastructure distinct from Epic for enhanced functionality. Here, we describe the development and implementation of the KP.

  12. Electron-capture GLC determination of clobazam and desmethylclobazam in plasma.

    Science.gov (United States)

    Greenblatt, D J

    1980-11-01

    Electron-capture GLC was utilized for simultaneous quantitation of clobazam, a 1,5-benzodiazepine derivative, and its active metabolite, desmethylclobazam, in human plasma and serum. After addition of diazepam as the internal standard, samples were extracted into benzene--isopentanol. The organic extracts were evaporated to dryness, reconstituted, and subjected to chromatographic analysis without derivatization or cleanup. All three compounds were resolved completely and had favorable chromatographic properties using an OV-101 liquid phase. The limits of detection are 3--5 ng/ml for clobazam and 5--10 ng/ml for desmethylclobazam. Relative standard deviations for identical samples do not exceed 6%. The application of the method to a clinical pharmacokinetic study is demonstrated.

  13. New Limits on Double Electron Capture of 40Ca and 180W

    CERN Document Server

    Angloher, G; Bauer, P; Bavykina, I; Bento, A; Bucci, C; Canonica, L; Ciemniak, C; Defay, X; Deuter, G; Erb, A; Feilitzsch, F v; Iachellini, N Ferreiro; Gorla, P; Gütlein, A; Hauff, D; Huff, P; Isaila, C; Jochum, J; Kiefer, M; Kimmerle, M; Kluck, H; Kraus, H; Lanfranchi, J -C; Loebell, J; Münster, A; Pagliarone, C; Petricca, F; Pfister, S; Potzel, W; Pröbst, F; Reindl, F; Roth, S; Rottler, K; Sailer, C; Schäffner, K; Schieck, J; Schmaler, J; Scholl, S; Schönert, S; Seidel, W; Sivers, M v; Stodolsky, L; Strandhagen, C; Strauss, R; Tanzke, A; Tretyak, V; Thi, H H Trinh; Türkoğlu, C; Uffinger, M; Ulrich, A; Usherov, I; Wawoczny, S; Willers, M; Wüstrich, M; Zöller, A

    2016-01-01

    We analyzed low-background data from the CRESST-II experiment with a total net exposure of 730 kg days to extract limits on double electron capture processes. We established new limits for 40Ca with T1/2 2v2K >9.9x10^21 y and T1/2 0v2EC >1.4x10^22 y and for 180W with T1/2 2v2K >3.1x10^19 y and T1/2 0v2EC >9.4x10^18 y at 90% CL. These values improve the currently best limits by up to a factor of ~30.

  14. Do electron-capture supernovae make neutron stars? First multidimensional hydrodynamic simulations of the oxygen deflagration

    CERN Document Server

    Jones, Samuel; Pakmor, Ruediger; Seitenzahl, Ivo R; Ohlmann, Sebastian T; Edelmann, Philipp V F

    2016-01-01

    In the classical picture, electron-capture supernovae and the accretion-induced collapse of oxygen-neon white dwarfs undergo an oxygen deflagration phase before gravitational collapse produces a neutron star. Such core collapse events are postulated to explain several astronomical phenomena. In this work, the oxygen deflagration phase is simulated for the first time using multidimensional hydrodynamics. By simulating the oxygen deflagration with multidimensional hydrodynamics and a level-set based flame approach, new insights can be gained into the explosive deaths of 8--10 solar-mass stars and oxygen-neon white dwarfs accreting material from a binary companion star. The main aim is to determine whether these events are thermonuclear or core-collapse supernova explosions, and hence whether neutron stars are formed by such phenomena. The oxygen deflagration is simulated in oxygen-neon cores with three different central ignition densities. The intermediate density case is perhaps the most realistic based on rec...

  15. Q value and half-life of double-electron capture in Os-184

    CERN Document Server

    Smorra, C; Beyer, T; Blaum, K; Block, M; Düllmann, Ch E; Eberhardt, K; Eibach, M; Eliseev, S; Langanke, K; Martinez-Pinedo, G; Nagy, Sz; Nörtershäuser, W; Renisch, D; Shabaev, V M; Tupitsyn, I I; Zubova, N A

    2012-01-01

    Os-184 has been excluded as a promising candidate for the search of neutrinoless double-electron capture. High-precision mass measurements with the Penning-trap mass spectrometer TRIGA-TRAP resulted in a marginal resonant enhancement with = -8.89(58) keV excess energy to the 1322.152(22) keV 0+ excited state in W-184. State-of-the-art energy density functional calculations are applied for the evaluation of the nuclear matrix elements to the excited states predicting a strong suppression due to the large deformation of mother and daughter states. The half-life of the transition in Os-184 exceeds T_{1/2} > 1.3 10^{29} years for an effective neutrino mass of 1 eV.

  16. A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry.

    Science.gov (United States)

    Hart-Smith, Gene

    2014-01-15

    Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community.

  17. Experimental and modeling study of thermal rate coefficients and cross sections for electron attachment to C(60).

    Science.gov (United States)

    Viggiano, Albert A; Friedman, Jeffrey F; Shuman, Nicholas S; Miller, Thomas M; Schaffer, Linda C; Troe, Jürgen

    2010-05-21

    Thermal electron attachment to C(60) has been studied by relative rate measurements in a flowing afterglow Langmuir probe apparatus. The rate coefficients of the attachment k(1) are shown to be close to 10(-6) cm(3) s(-1) with a small negative temperature coefficient. These results supersede measurements from the 1990s which led to much smaller values of k(1) with a large positive temperature coefficient suggesting an activation barrier. Theoretical modeling of k(1) in terms of generalized Vogt-Wannier capture theory shows that k(1) now looks more consistent with measurements of absolute attachment cross sections sigma(at) than before. The comparison of capture theory and experimental rate or cross section data leads to empirical correction factors, accounting for "intramolecular vibrational relaxation" or "electron-phonon coupling," which reduce k(1) below the capture results and which, on a partial wave-selected level, decrease with increasing electron energy.

  18. The Electron Capture Decay of 163-Ho to Measure the Electron Neutrino Mass with sub-eV Accuracy and Beyond

    CERN Document Server

    Gatti, Flavio; Lusignoli, Maurizio; Nucciotti, Angelo; Ragazzi, Stefano

    2012-01-01

    We have investigated the possibility of measuring the electron neutrino mass with sub-eV sensitivity by studying the electron capture decay of 163-Ho with cryogenic microcalorimeters. In this paper we will introduce an experiment's concept, discuss the technical requirements, and identify a roadmap to reach a sensitivity of 0.1 eV and beyond.

  19. Electron-capture supernovae as the origin of elements beyond iron

    CERN Document Server

    Wanajo, Shinya; Mueller, Bernhard

    2010-01-01

    We examine electron-capture supernovae (ECSNe) as sources of elements heavier than iron in the solar system and in Galactic halo stars. Nucleosynthesis calculations are performed on the basis of thermodynamic histories of mass elements from a fully self-consistent, two-dimensional (2D) hydrodynamic explosion model of an ECSN. We find that neutron-rich convective lumps with an electron fraction down to Ye,min=0.40, which are absent in the one-dimensional (1D) counterpart, allow for interesting production of elements between the iron group and N=50 nuclei (from Zn to Zr, with little Ga) in nuclear statistical equilibrium and by the alpha-process. Our models yield very good agreement with the Ge, Sr, Y, and Zr abundances of r-process deficient Galactic halo stars and constrain the occurrence of ECSNe to ~4% of all stellar core-collapse events. If tiny amounts of additional material with slightly lower Ye,min down to ~0.30-0.35 were also ejected - which presently cannot be excluded because of the limitations of r...

  20. A search for double-electron capture in 74Se using coincidence/anticoincidence gamma-ray spectrometry

    CERN Document Server

    Jeskovsky, M; Kovacik, A; Povinec, P P; Puppe, P; Stanicek, J; Sykora, I; Simkovic, F; Thies, J H

    2015-01-01

    Evaluation of single, coincidence and anticoincidence gamma-ray spectrometry methods has been carried out with the aim to search for double-electron capture in 74Se. This process is unique, because there is probability for transition to the 2+ excited state in 74Ge (1204 keV), and de-excitation through two gamma-quanta cascade with energies of 595.9 keV and 608.4 keV. Long-term measurements with anticosmic shielded HPGe spectrometer and the coincidence HPGe-NaI(Tl) spectrometer did not show any evidence for the double-electron capture in 74Se. The best limit for the half-life of the double electron capture in 74Se (both for the neutrinoless and two neutrino processes) was estimated to be >1.5x10E19 years.

  1. Electronic data capture in a rural African setting: evaluating experiences with different systems in Malawi.

    Science.gov (United States)

    King, Carina; Hall, Jenny; Banda, Masford; Beard, James; Bird, Jon; Kazembe, Peter; Fottrell, Ed

    2014-12-01

    Background As hardware for electronic data capture (EDC), such as smartphones or tablets, becomes cheaper and more widely available, the potential for using such hardware as data capture tools in routine healthcare and research is increasing. Objective We aim to highlight the advantages and disadvantages of four EDC systems being used simultaneously in rural Malawi: two for Android devices (CommCare and ODK Collect), one for PALM and Windows OS (Pendragon), and a custom-built application for Android (Mobile InterVA - MIVA). Design We report on the personal field and development experience of fieldworkers, project managers, and EDC system developers. Results Fieldworkers preferred using EDC to paper-based systems, although some struggled with the technology at first. Highlighted features include in-built skip patterns for all systems, and specifically the 'case' function that CommCare offers. MIVA as a standalone app required considerably more time and expertise than the other systems to create and could not be customised for our specific research needs; however, it facilitates standardised routine data collection. CommCare and ODK Collect both have user-friendly web-interfaces for form development and good technical support. CommCare requires Internet to build an application and download it to a device, whereas all steps can be done offline with ODK Collect, a desirable feature in low connectivity settings. Pendragon required more complex programming of logic, using a Microsoft Access application, and generally had less technical support. Start-up costs varied between systems, and all were considered more expensive than setting up a paper-based system; however running costs were generally low and therefore thought to be cost-effective over the course of our projects. Conclusions EDC offers many opportunities for efficient data collection, but brings some issues requiring consideration when designing a study; the decision of which hardware and software to use should

  2. Origin of meteoritic stardust unveiled by a revised proton-capture rate of 17O

    Science.gov (United States)

    Lugaro, M.; Karakas, A. I.; Bruno, C. G.; Aliotta, M.; Nittler, L. R.; Bemmerer, D.; Best, A.; Boeltzig, A.; Broggini, C.; Caciolli, A.; Cavanna, F.; Ciani, G. F.; Corvisiero, P.; Davinson, T.; Depalo, R.; di Leva, A.; Elekes, Z.; Ferraro, F.; Formicola, A.; Fülöp, Zs.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, Gy.; Imbriani, G.; Junker, M.; Menegazzo, R.; Mossa, V.; Pantaleo, F. R.; Piatti, D.; Prati, P.; Scott, D. A.; Straniero, O.; Strieder, F.; Szücs, T.; Takács, M. P.; Trezzi, D.

    2017-01-01

    Stardust grains recovered from meteorites provide high-precision snapshots of the isotopic composition of the stellar environment in which they formed 1 . Attributing their origin to specific types of stars, however, often proves difficult. Intermediate-mass stars of 4-8 solar masses are expected to have contributed a large fraction of meteoritic stardust 2,3 . Yet, no grains have been found with the characteristic isotopic compositions expected for such stars 4,5 . This is a long-standing puzzle, which points to serious gaps in our understanding of the lifecycle of stars and dust in our Galaxy. Here we show that the increased proton-capture rate of 17O reported by a recent underground experiment 6 leads to 17O/16O isotopic ratios that match those observed in a population of stardust grainsfor proton-burning temperatures of 60-80 MK. These temperatures are achieved at the base of the convective envelope during the late evolution of intermediate-mass stars of 4-8 solar masses 7-9 , which reveals them as the most likely site of origin of the grains. This result provides direct evidence that these stars contributed to the dust inventory from which the Solar System formed.

  3. Theoretical investigation of energy deposition and electron capture cross-sections for helium ion impact on formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Trujillo, R. [Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, FL 32611-8435 (United States); Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, Cuernavaca, Morelos, 62251 (Mexico); Sabin, John R. [Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, FL 32611-8435 (United States)]. E-mail: sabin@qtp.ufl.edu; Deumens, Erik [Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, FL 32611-8435 (United States); Ohrn, Yngve [Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, FL 32611-8435 (United States)

    2007-08-15

    The subject of the work presented here is related to damage caused by energetic, charged particle radiation such as electrons, protons, and alpha particles to prebiotic matter such as that found in interstellar space. The calculations are carried out using an all electron, all nuclei, scheme that explicitly treats the electron-nuclear coupling. We present results for the no-capture, as well as the single and double electron capture probabilities, as well as for the 1s and 2l (l = s, p) contributions to the electron capture cross-sections of {sup 3}He{sup 2+} projectiles on formaldehyde molecules. We find that the summed cross-section peaks at 10 keV/amu, and has a plateau between 0.1 and 1 keV/amu. We also present preliminary results for the nuclear, ro-vibrational and electronic stopping cross-section. We find a large contribution to the electronic stopping cross-section and a maximum shifted towards higher energies in the nuclear stopping cross-section, when compared to SRIM results. We interpret this to be a consequence of molecular bonding.

  4. The electron energy loss rate due to radiative recombination

    Science.gov (United States)

    Mao, Junjie; Kaastra, Jelle; Badnell, N. R.

    2017-02-01

    Context. For photoionized plasmas, electron energy loss rates due to radiative recombination (RR) are required for thermal equilibrium calculations, which assume a local balance between the energy gain and loss. While many calculations of total and/or partial RR rates are available from the literature, specific calculations of associated RR electron energy loss rates are lacking. Aims: Here we focus on electron energy loss rates due to radiative recombination of H-like to Ne-like ions for all the elements up to and including zinc (Z = 30), over a wide temperature range. Methods: We used the AUTOSTRUCTURE code to calculate the level-resolved photoionization cross section and modify the ADASRR code so that we can simultaneously obtain level-resolved RR rate coefficients and associated RR electron energy loss rate coefficients. We compared the total RR rates and electron energy loss rates of H i and He i with those found in the literature. Furthermore, we utilized and parameterized the weighted electron energy loss factors (dimensionless) to characterize total electron energy loss rates due to RR. Results: The RR electron energy loss data are archived according to the Atomic Data and Analysis Structure (ADAS) data class adf48. The RR electron energy loss data are also incorporated into the SPEX code for detailed modeling of photoionized plamsas. Full Tables 1 and 2 are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A10

  5. Effect of collective response on electron capture and excitation in collisions of highly charged ions with fullerenes.

    Science.gov (United States)

    Kadhane, U; Misra, D; Singh, Y P; Tribedi, Lokesh C

    2003-03-07

    Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions.

  6. Capturing relativistic wake eld structures in plasmas using ultrashort high-energy electrons as a probe

    CERN Document Server

    Zhang, C J; Xu, X L; Li, F; Pai, C -H; Wan, Y; Wu, Y P; Gu, Y Q; Mori, W B; Joshi, C; Lu, W

    2016-01-01

    A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime...

  7. Rapid determination of acrylamide contaminant in conventional fried foods by gas chromatography with electron capture detector.

    Science.gov (United States)

    Zhang, Yu; Dong, Yi; Ren, Yiping; Zhang, Ying

    2006-05-26

    Gas chromatography coupled with electron capture detector (GC-ECD) was successfully developed and applied for the rapid determination of acrylamide in conventional fried foods, such as potato crisps, potato chips, and fried chicken wings. The method included defatting with n-hexane, extraction with aqueous solution of sodium chloride (NaCl), derivatization with potassium bromate (KBrO3) and potassium bromide (KBr), and liquid-liquid extraction with ethyl acetate. The final acrylamide extract was analyzed by GC-ECD for quantification and by GC-MS for confirmation. The chromatographic analysis was performed on the HP-INNOWax capillary column, and good retention and peak response of acrylamide were achieved under the optimal conditions (numbers of theoretical plates N = 83,815). The limit of detection (LOD) was estimated to be 0.1 microg kg(-1) on the basis of ECD technique. Recoveries of acrylamide from conventional samples spiked at levels of 150, 500 and 1000 microg kg(-1) (n = 4 for each level) ranged between 87 and 97% with relative standard deviations (RSD) of less than 4%. Furthermore, the GC-ECD method showed that no clean-up steps of acrylamide derivative would be performed prior to injection and was slightly more sensitive than the MS/MS-based methods. Validation and quantification results demonstrated that this method should be regarded as a new, low-cost, and robust alternative for conventional investigation of acrylamide.

  8. Determination of guaifenesin in human serum by capillary gas chromatography and electron capture detection.

    Science.gov (United States)

    Sharaf, Maged H M; Stiff, Dwight D

    2004-06-29

    A method for the quantitation of guaifenesin in human serum has been developed and validated. The procedure involves liquid-liquid extraction of the serum sample in the presence of mephenesin as an internal standard, followed by derivatization and analysis using capillary gas chromatography (GC) and electron capture detection (ECD). Different solvents were tested for extraction of guaifenesin from serum. n-Hexane/dichloromethane (1:1, v/v) gave the highest recovery and the lowest background and was chosen as the extraction solvent. After extraction, the residue of guaifenesin was derivatized at 60 degrees C for 30 min, with trifluoroacetic acid anhydride (TFAA) in toluene in the presence of pyridine. Excess trifluoroacetic acid anhydride was removed using dilute solution of ammonium hydroxide. The method proved to be linear over the range of 25.0-1000 ng/ml. Recovery of guaifenesin from spiked samples was consistent, averaging 75.5% at 50.0 ng/ml with a range of 72.0-80.0% (N = 8 determinations) and averaging 78% at 800 ng/ml with a range of 76.0-81.0% (N = 8 determinations). The internal standard recovery was also consistent averaging 72.8% with a range of 67.0-76.0% (N = 16 determinations). Copyright 2004 Elsevier B.V.

  9. Octopamine Levels in Blattella Germanica L. Tissues by Capillary Gas Chromatography with Electron Capture Detection

    Directory of Open Access Journals (Sweden)

    Shuren Jiang

    2005-05-01

    Full Text Available Abstract: Distribution and levels of octopamine (OA, one of the biogenic amines in the invertebrate nervous system, may have significant effects on insect physiological processes including growth, feeding and reproduction. In this paper capillary gas chromatography with electron capture detection (GC-ECD and mass selective detection (GC-MS were used to determine the content of OA in Blattella germanica L. central nervous system (CNS, and that of OA in cockroach stressed by kinds of insecticides, known octopaminergic agonists and some essential oils. A derivatization method for organic extracts via reaction with pentafluoropropionic anhydride (PFPA was developed. The resulting OA derivatives were confirmed by GC-MS to be tris-pentafluoropropionyl-OA. The method was used to quantify the amount of OA in insect issues by capillary GC-ECD through an extraction-derivatization-liquid/liquid partition procedure. Average OA content in normal cockroaches was determined to be 68.49 ± 7.31 ng/g tissue (N=5 determinations. It was shown that insecticides including chlordimeform, methomyl, permethrin, chlorfluazuron, malathion, trichlorfon and some oxazolidine agonists, essential oils including eugenol, cinnamic alcohol, phenyl ethyl alcohol could led to significant increase of OA levels in the cockroach CNS comparing with which in insect treated by 1-butanone. Malathion, trichlorfon, chlorfluazuron and cinnamic alcohol were shown to be able to cause a 20- fold increase in OA levels.

  10. A study of resonance electron capture ionization on a quadrupole tandem mass spectrometer.

    Science.gov (United States)

    Wei, J; Liu, S; Fedoreyev, S A; Voinov, V G

    2000-01-01

    Procedures that allow the realization of resonance electron capture (REC) mode on a commercial triple-quadrupole mass spectrometer, after some simple modifications, are described. REC mass spectrometry (MS) and tandem mass spectrometry (MS/MS) experiments were performed and spectra for some compounds were recorded. In particular, the charge-remote fragmentation (CRF) spectra of [M - H](-) ions of docosanoic and docosenoic acids under low-energy collisionally activated dissociation (CAD) conditions were obtained, and showed that there were no significant differences for [M - H](-) ions produced at different resonances (i.e. for [M - H](-) ions with different structures). This observation was explained on the basis of results obtained from deuterium-labeled fatty acids, which showed that different CRF ions (but with the same m/z value in the absence of labels) could be produced by different mechanisms, and all of them were obviously realized under CAD conditions that made spectra practically indistinguishable. The other example, which compared the REC-MS/MS spectrum of [M - H](-) ions and EI-MS/MS spectrum of M(+.) ions of daidzein, demonstrated the potential of the REC-MS/MS technique for more complex structure elucidation.

  11. The Impact of Phosphorylation on Electron Capture Dissociation of Proteins: A Top-Down Perspective

    Science.gov (United States)

    Chen, Bifan; Guo, Xiao; Tucholski, Trisha; Lin, Ziqing; McIlwain, Sean; Ge, Ying

    2017-09-01

    Electron capture dissociation (ECD) is well suited for the characterization of phosphoproteins, with which labile phosphate groups are generally preserved during the fragmentation process. However, the impact of phosphorylation on ECD fragmentation of intact proteins remains unclear. Here, we have performed a systematic investigation of the phosphorylation effect on ECD of intact proteins by comparing the ECD cleavages of mono-phosphorylated α-casein, multi-phosphorylated β-casein, and immunoaffinity-purified phosphorylated cardiac troponin I with those of their unphosphorylated counterparts, respectively. In contrast to phosphopeptides, phosphorylation has significantly reduced deleterious effects on the fragmentation of intact proteins during ECD. On a global scale, the fragmentation patterns are highly comparable between unphosphorylated and phosphorylated precursors under the same ECD conditions, despite a slight decrease in the number of fragment ions observed for the phosphorylated forms. On a local scale, single phosphorylation of intact proteins imposes minimal effects on fragmentation near the phosphorylation sites, but multiple phosphorylations in close proximity result in a significant reduction of ECD bond cleavages. [Figure not available: see fulltext.

  12. Determination of fluvalinate residues in beeswax by gas chromatography with electron-capture detection.

    Science.gov (United States)

    Tsigouri, A; Menkissoglu-Spiroudi, U; Thrasyvoulou, A T; Diamantidis, G C

    2000-01-01

    A simple, rapid, and accurate method is described for the determination of residual fluvalinate in beeswax. The procedure consists of partitioning on a disposable column of diatomaceous earth (Extrelut), followed by chromatographic cleanup on a Florisil cartridge. The final extract is analyzed by capillary gas chromatography with electron-capture detection (GC-ECD). Briefly, wax samples were dissolved in n-hexane, and the solutions were sonicated and transferred to Extrelut columns. The fluvalinate was extracted with acetonitrile, and a portion of the extract was cleaned up on a Florisil cartridge. The fluvalinate was eluted with diethyl ether-n-hexane (1 + 1) and directly determined by GC-ECD. Recoveries from wax samples spiked at 5 fortification levels (100-1500 microg/kg) ranged from 77.4 to 87.3%, with coefficients of variation of 5.12-8.31%. The overall recovery of the method was 81.4 +/- 3.2%, and the limit of determination was 100 microg/kg.

  13. Determination of toxaphene enantiomers by comprehensive two-dimensional gas chromatography with electron-capture detection.

    Science.gov (United States)

    Bordajandi, Luisa R; Ramos, Lourdes; González, María José

    2006-09-01

    Comprehensive two-dimensional gas chromatography with micro electron-capture detection (GC x GC-microECD) has been evaluated for the enantioseparation of five chiral toxaphenes typically found in real-life samples (Parlar 26, 32, 40, 44 and 50). From the two enantioselective beta-cyclodextrin-based columns evaluated as first dimension column, BGB-176SE and BGB-172, the latter provided the best results and was further combined with three non-enantioselective columns in the second dimension: HT-8, BPX-50 and Supelcowax-10. The combination BGB-172 x BPX-50 was finally selected because it provided a complete separation among all enantiomers. A satisfactory repeatability and reproducibility of the retention times in both the first and the second dimension were observed for all target compounds (RSDs below 0.8%, n = 4). Linear responses in the tested range of 10-200 pg/microl and limits of detection in the range of 2-6 pg/microl were obtained. The repeatability and reproducibility at a concentration of 100 pg/microl, evaluated as the RSDs calculated for the enantiomeric fraction (EF), was better than 11% (n = 4) in all instances. The feasibility of the method developed for real-life analyses was illustrated by the determination of the enantiomeric ratios and concentration levels of the test compounds in four commercial fish oil samples. These results were compared to those obtained by heart-cut multidimensional gas chromatography using the same enantioselective column.

  14. Electronic data capture for registries and clinical trials in orthopaedic surgery: open source versus commercial systems.

    Science.gov (United States)

    Shah, Jatin; Rajgor, Dimple; Pradhan, Shreyasee; McCready, Mariana; Zaveri, Amrapali; Pietrobon, Ricardo

    2010-10-01

    Collection and analysis of clinical data can help orthopaedic surgeons to practice evidence based medicine. Spreadsheets and offline relational databases are prevalent, but not flexible, secure, workflow friendly and do not support the generation of standardized and interoperable data. Additionally these data collection applications usually do not follow a structured and planned approach which may result in failure to achieve the intended goal. Our purposes are (1) to provide a brief overview of EDC systems, their types, and related pros and cons as well as to describe commonly used EDC platforms and their features; and (2) describe simple steps involved in designing a registry/clinical study in DADOS P, an open source EDC system. WHERE ARE WE NOW?: Electronic data capture systems aimed at addressing these issues are widely being adopted at an institutional/national/international level but are lacking at an individual level. A wide array of features, relative pros and cons and different business models cause confusion and indecision among orthopaedic surgeons interested in implementing EDC systems. WHERE DO WE NEED TO GO?: To answer clinical questions and actively participate in clinical studies, orthopaedic surgeons should collect data in parallel to their clinical activities. Adopting a simple, user-friendly, and robust EDC system can facilitate the data collection process. HOW DO WE GET THERE?: Conducting a balanced evaluation of available options and comparing them with intended goals and requirements can help orthopaedic surgeons to make an informed choice.

  15. Electron capture sulfur detector: reduced sulfur species detection at the femtomole level

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.E.; Lovelock, J.E.

    1988-04-15

    The authors have developed a new technique to detect reduced sulfur compounds by fluorination with F/sub 2/ (at 200 ppm) on a heated Ag catalyst after GC separation. The excess F/sub 2/ is removed by conversion to HF by reaction with H/sub 2/ on a heated Pd catalysts. The fluorination product, presumably SF/sub 6/, is then detected in an electron capture detector (ECD). The Pd catalyst also destroys the response from halocarbons making the system sulfur specific. This ECD sulfur detector has a calculated minimum detectable level (MDL) for H/sub 2/S, OCS, CH/sub 3/SH, DMS, and CS/sub 2/ of less than 2 fmol/s for each compound, 2 orders of magnitude lower than the best FPD systems. The ratio of the detected molar response of each of these sulfur compounds to the molar response of SF/sub 6/ ranges from 2% to 20% and increases with increasing AgF/sub 2/ temperature.

  16. Trace analysis of sulfamethazine in animal feed, human urine, and wastewater by electron capture gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Holder, C.L.; Thompson, H.C. Jr.; Bowman, M.C.

    1981-12-01

    Sulfamethazine, a widely used antibacterial drug additive in feeds for swine, chickens, and cattle, was scheduled for toxicological evaluation because of potential human health hazards associated with its residues in edible animal tissues. Analytical chemical procedures that would ensure proper concentration, homogeneity, and stability of the drug in dosed feed and its safe usage during the animal studies were prerequisites for such toxicological tests. Electron capture gas chromatographic (EC/GC) methods were therefore devised for the analysis of sulfamethazine residues in animal feed, human urine, and wastewater at levels as low as 100, 10, and 10 ppb, respectively. Sample extracts were cleaned up by using liquid/liquid partitioning, and the extracts were subjected to two derivatizations followed by cleanup on a silica gel column. The derivatizations of sulfamethazine consisted of methylation followed by trifluoroacetylation of the primary amine function. Ancillary data concerning stability of the compound in animal feed, water, and as a dry residue on glass, extraction efficiencies, partition values with various solvents, and the analysis of residues in feed by high pressure liquid chromatography (HPLC) at levels as low as 1.0 ppm are presented.

  17. Comparison of peptide mass mapping and electron capture dissociation as assays for histone posttranslational modifications

    Science.gov (United States)

    Zhang, Liwen; Freitas, Michael A.

    2004-05-01

    Posttranslational modifications of core histones play a critical role in the structure of chromatin and the regulation of gene activities. Improved techniques for determining these modification sites may lead to a better understanding of histone regulation at the molecular level. LC-MS peptide mass mapping was performed on pepsin, trypsin and Glu-C digests of bovine thymus H4 using a QqTOF instrument. The well established modification sites of H4 (acetylation of K8, 12, 16 and methylation of K20) were observed in addition to several recently discovered modifications including: methylation of K31, 44, 59 and acetylation of K20, 77, 79. For comparison, electron capture dissociation (ECD) was performed on intact H4 along with several peptides from enzymatic digestion. The results from the ECD experiments of histone H4 indicated the acetylation of K5, 12, 16, 31, 91 and the methylation of K20 and 59 in good agreement with the result from peptide mapping. The work is dedicated to Alan G. Marshall on his 60th birthday. His endeavors in the advancement of FT-ICR facilitated experiments reported herein.

  18. Electron-capture delayed fission properties of neutron-deficient einsteinium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Shaughnessy, Dawn A. [Univ. of California, Berkeley, CA (United States)

    2000-01-01

    Electron-capture delayed fission (ECDF) properties of neutron-deficient einsteinium isotopes were investigated using a combination of chemical separations and on-line radiation detection methods. 242Es was produced via the 233U(14N,5n)242Es reaction at a beam energy of 87 MeV (on target) in the lab system, and was found to decay with a half-life of 11 ± 3 seconds. The ECDF of 242Es showed a highly asymmetric mass distribution with an average pre-neutron emission total kinetic energy (TKE) of 183 ± 18 MeV. The probability of delayed fission (PDF) was measured to be 0.006 ± 0.002. In conjunction with this experiment, the excitation functions of the 233U(14N,xn)247-xEs and 233U(15N,xn)248-xEs reactions were measured for 243Es, 244Es and 245Es at projectile energies between 80 MeV and 100 MeV.

  19. Correlated Two-Electron Capture by Ion with Emission of Photon

    Science.gov (United States)

    Mikhailov, A. I.

    2005-05-01

    The correlated double electron capture into the K shell of bare ions with emission of a single photon is considered. The process is treated as a time-reversed atomic double photoionization. For ten years of experimental investigations there is no evidence of existence of the reaction. There is a theoretical prediction (Phys. Rev. A 55 (1997) 1952), that a probability of the process grows rapidly with the ion charge due to relativistic effects and that the cross section does not depend on target atoms. However the recent experiment (GSI Scien.Rep., ISSN 174 (2001) 98) failed to observe this process under the recommended conditions. The present work reveals an incorrectness of those theoretical predictions and provides an expression to determine optimal experimental conditions for observing the process. We suggest to use ion beams slower than those in the experiment (NIM B98 (1995)303), and do not recommend to use heavy ions. We show that the cross section can increase significantly for solid-state targets and decelerated ion beams. The novel technique of deceleration of multicharged ions planned at GSI can be applied to perform such experiments.

  20. Study of the inner Bremsstrahlung following the electron-capture decay of {sup 193} Pt

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, J.Y.Z.; Cruz, M.T.F. da; Martins, M.N.; Santos, R.T. dos [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Zamboni, C.B.; Hamada, M.M.; Camargo, S.P. de; Medeiros, J.A.G. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Hindi, M.M. [Tennessee Technological Univ., Cookeville, TN (United States). Dept. of Physics

    1997-12-31

    We are measuring the inner Bremsstrahlung (I B) photons emitted in some of the electron-capture decays of {sup 193} Pt. The source was prepared with highly pure metal Pt. It was irradiated with neutron for 52 days and let to cool down for eight months. The remaining activities were due to {sup 193} Pt{sup g} (half-life 50 yr) and {sup 192} Ir (half-life 74 d), the latter coming from (n, {gamma}) reactions on a small content of Ir. We have used a radiochemistry method to reduce the Ir content of the source. The resulting Pt compound will be dissolved in a plastic scintillator disk. Most of the {sup 192} Ir decays are {beta}{sup -} and their signal in the plastic will be used as a veto for the I B-photon detector. We have performed simulations of the efficiency and absorption effects in the detection geometry. (author) 6 refs., 1 fig.; juan at if.usp.br; czamboni at net.ipen.br; hindi at hindi.physics.tntech.edu

  1. Kuang's Semi-Classical Formalism for Calculating Electron Capture Cross Sections and Sample Application for ENA Modeling

    Science.gov (United States)

    Barghouty, A. F.

    2013-01-01

    Accurate estimates of electron-capture cross sections at energies relevant to ENA modeling (approx. few MeV per nucleon) and for multi-electron ions must rely on detailed, but computationally expensive, quantummechanical description of the collision process. Kuang's semi-classical approach is an elegant and efficient way to arrive at these estimates. Motivated by ENA modeling efforts, we shall briefly present this approach along with sample applications and report on current progress.

  2. Relationship between mosquito (Diptera: Culicidae) landing rates on a human subject and numbers captured using CO2-baited light traps.

    Science.gov (United States)

    Barnard, D R; Knue, G J; Dickerson, C Z; Bernier, U R; Kline, D L

    2011-06-01

    Capture rates of insectary-reared female Aedes albopictus (Skuse), Anopheles quadrimaculatus Say, Culex nigripalpus Theobald, Culex quinquefasciatus Say and Aedes triseriatus (Say) in CDC-type light traps (LT) supplemented with CO2 and using the human landing (HL) collection method were observed in matched-pair experiments in outdoor screened enclosures. Mosquito responses were compared on a catch-per-unit-effort basis using regression analysis with LT and HL as the dependent and independent variables, respectively. The average number of mosquitoes captured in 1 min by LT over a 24-h period was significantly related to the average number captured in 1 min by HL only for Cx. nigripalpus and Cx. quinquefasciatus. Patterns of diel activity indicated by a comparison of the mean response to LT and HL at eight different times in a 24-h period were not superposable for any species. The capture rate efficiency of LT when compared with HL was ≤15% for all mosquitoes except Cx. quinquefasciatus (43%). Statistical models of the relationship between mosquito responses to each collection method indicate that, except for Ae. albopictus, LT and HL capture rates are significantly related only during certain times of the diel period. Estimates of mosquito activity based on observations made between sunset and sunrise were most precise in this regard for An. quadrimaculatus and Cx. nigripalpus, as were those between sunrise and sunset for Cx. quinquefasciatus and Ae. triseriatus.

  3. State-selective electron-capture measurements for N4+-H and N4+-H-2 collisions

    NARCIS (Netherlands)

    Bliek, FW; Woestenenk, GR; Hoekstra, R; Morgenstern, R

    1998-01-01

    State-selective electron-capture cross-section measurements in the energy range between 1 and 4 keV/amu are reported for collisions between N4+ ions and atomic and molecular hydrogen. The cross sections are measured in a crossed-beam experiment by means of photon emission spectroscopy. The singlet a

  4. Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionisation mass spectrometry

    NARCIS (Netherlands)

    Rusina, T.; Korytar, P.; Boer, de J.

    2011-01-01

    Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group pattern

  5. DEPENDENCE OF ELECTRON-CAPTURE FROM NA-ASTERISK(3P) ON ORBITAL ALIGNMENT - A KINEMATIC EFFECT

    NARCIS (Netherlands)

    SCHLATMANN, AR; MORGENSTERN, R

    1993-01-01

    Recent experimental data of electron capture into He+(4l) states from SIGMA and PI aligned Na*(3p) orbitals are interpreted. Calculations of the overlap integral of the initial Na*(3p) and the final He+(4l) wavefunctions in momentum space reproduce the velocity dependence of the measured cross secti

  6. Are there any agricultural effects on the capture rates of male euglossine bees (Apidae: Euglossini)?

    Science.gov (United States)

    Sandino, Juan Carlos

    2004-03-01

    During 30 days male euglossine bees were bait-sampled at 12 sites, in the central Pacific coast of Colombia (ten days and four sites at each of three adjacent habitats: farmlands, highly disturbed forest and less disturbed forest) and 487 individuals were captured. Most captured individuals belonged to six species, five widely distributed through the American tropics and an endemic species. Two of the frequently captured species presented no different abundances between habitats, while the other four (67.97% of all the captured individuals), all of them big sized or long-tongued, were more frequently captured at the farmlands. A cluster analysis of the data matrix for the 23 captured species and the 12 sampling sites, grouped together the farmland sites, apart from the forest sites. It is proposed that male euglossine bees from generalist, long-tongued or big sized species, forage frequently at the farmlands, where fragrance or nectar resources may be clumped, less diverse, and present an access restricted by deep corollas or by microclimatic conditions of high temperature and low humidity.

  7. Electronic data capture in a rural African setting: evaluating experiences with different systems in Malawi

    Directory of Open Access Journals (Sweden)

    Carina King

    2014-10-01

    Full Text Available Background: As hardware for electronic data capture (EDC, such as smartphones or tablets, becomes cheaper and more widely available, the potential for using such hardware as data capture tools in routine healthcare and research is increasing. Objective: We aim to highlight the advantages and disadvantages of four EDC systems being used simultaneously in rural Malawi: two for Android devices (CommCare and ODK Collect, one for PALM and Windows OS (Pendragon, and a custom-built application for Android (Mobile InterVA – MIVA. Design: We report on the personal field and development experience of fieldworkers, project managers, and EDC system developers. Results: Fieldworkers preferred using EDC to paper-based systems, although some struggled with the technology at first. Highlighted features include in-built skip patterns for all systems, and specifically the ‘case’ function that CommCare offers. MIVA as a standalone app required considerably more time and expertise than the other systems to create and could not be customised for our specific research needs; however, it facilitates standardised routine data collection. CommCare and ODK Collect both have user-friendly web-interfaces for form development and good technical support. CommCare requires Internet to build an application and download it to a device, whereas all steps can be done offline with ODK Collect, a desirable feature in low connectivity settings. Pendragon required more complex programming of logic, using a Microsoft Access application, and generally had less technical support. Start-up costs varied between systems, and all were considered more expensive than setting up a paper-based system; however running costs were generally low and therefore thought to be cost-effective over the course of our projects. Conclusions: EDC offers many opportunities for efficient data collection, but brings some issues requiring consideration when designing a study; the decision of which hardware

  8. Breakdown behavior of electronics at variable pulse repetition rates

    OpenAIRE

    Korte, S.; H. Garbe

    2006-01-01

    The breakdown behavior of electronics exposed to single transient electromagnetic pulses is subject of investigations for several years. State-of-the-art pulse generators additionally provide the possibility to generate pulse sequences with variable pulse repetition rate. In this article the influence of this repetition rate variation on the breakdown behavior of electronic systems is described. For this purpose microcontroller systems are examined during line-led exposure to pulses with repe...

  9. Determination of prey capture rates in the stony coral Galaxea fascicularis: a critical reconsideration of the clearance rate concept

    NARCIS (Netherlands)

    Osinga, R.; Delft, van S.; Lewaru, M.W.; Janse, M.; Verreth, J.A.J.

    2012-01-01

    In order to determine optimal feeding regimes for captive corals, prey capture by the scleractinian coral Galaxea fascicularis was determined by measuring clearance of prey items from the surrounding water. Colonies of G. fascicularis (sized between 200 and 400 polyps) were incubated in 1300 ml incu

  10. Human resource requirements for quality-assured electronic data capture of the tuberculosis case register

    Directory of Open Access Journals (Sweden)

    Hoa Nguyen B

    2012-01-01

    Full Text Available Abstract Background The tuberculosis case register is the data source for the reports submitted by basic management units to the national tuberculosis program. Our objective was to measure the data entry time required to complete and double-enter one record, and to estimate the time for the correction of errors in the captured information from tuberculosis case registers in Cambodia and Viet Nam. This should assist in quantifying the additional requirements in human resources for national programs moving towards electronic recording and reporting. Methods Data from a representative sample of tuberculosis case registers from Cambodia and Viet Nam were double-entered and discordances resolved by rechecking the original case register. Computer-generated data entry time recorded the time elapsed between opening of a new record and saving it to disk. Results The dataset comprised 22,732 double-entered records of 11,366 patients (37.1% from Cambodia and 62.9% from Viet Nam. The mean data entry times per record were 97.5 (95% CI: 96.2-98.8 and 66.2 (95% CI: 59.5-73.0 seconds with medians of 90 and 31 s respectively in Cambodia and in Viet Nam. The percentage of records with an error was 6.0% and 39.0% respectively in Cambodia and Viet Nam. Data entry time was inversely associated with error frequency. We estimate that approximately 118-person-hours were required to produce 1,000 validated records. Conclusions This study quantifies differences between two countries for data entry time for the tuberculosis case register and frequencies of data entry errors and suggests that higher data entry speed is partially offset by requiring revisiting more records for corrections.

  11. On decay constants and orbital distance to the Sun—part III: beta plus and electron capture decay

    Science.gov (United States)

    Pommé, S.; Stroh, H.; Paepen, J.; Van Ammel, R.; Marouli, M.; Altzitzoglou, T.; Hult, M.; Kossert, K.; Nähle, O.; Schrader, H.; Juget, F.; Bailat, C.; Nedjadi, Y.; Bochud, F.; Buchillier, T.; Michotte, C.; Courte, S.; van Rooy, M. W.; van Staden, M. J.; Lubbe, J.; Simpson, B. R. S.; Fazio, A.; De Felice, P.; Jackson, T. W.; Van Wyngaardt, W. M.; Reinhard, M. I.; Golya, J.; Bourke, S.; Roy, T.; Galea, R.; Keightley, J. D.; Ferreira, K. M.; Collins, S. M.; Ceccatelli, A.; Verheyen, L.; Bruggeman, M.; Vodenik, B.; Korun, M.; Chisté, V.; Amiot, M.-N.

    2017-02-01

    The hypothesis that seasonal changes in proximity to the Sun cause variation of decay constants at permille level has been tested for radionuclides disintegrating through electron capture and beta plus decay. Activity measurements of 22Na, 54Mn, 55Fe, 57Co, 65Zn, 82+85Sr, 90Sr, 109Cd, 124Sb, 133Ba, 152Eu, and 207Bi sources were repeated over periods from 200 d up to more than four decades at 14 laboratories across the globe. Residuals from the exponential nuclear decay curves were inspected for annual oscillations. Systematic deviations from a purely exponential decay curve differ from one data set to another and appear attributable to instabilities in the instrumentation and measurement conditions. Oscillations in phase with Earth’s orbital distance to the sun could not be observed within 10-4-10-5 range precision. The most stable activity measurements of β + and EC decaying sources set an upper limit of 0.006% or less to the amplitude of annual oscillations in the decay rate. There are no apparent indications for systematic oscillations at a level of weeks or months.

  12. Development of an electronic research permissions management system to enhance informed consents and capture research authorizations data.

    Science.gov (United States)

    Obeid, Jihad S; Gerken, Katherine; Madathil, Kapil Chalil; Rugg, Daniel; Alstad, Colin E; Fryar, Katrina; Alexander, Randall; Gramopadhye, Anand K; Moskowitz, Jay; Sanderson, Iain C

    2013-01-01

    Informed consents are a critical and essential component of the clinical research process. Currently, most consents and research privacy authorizations are being captured on paper. In this paper we describe a novel method of capturing this information electronically. The objective is to allow easier tracking of research participants' intent for current and future research involvement, enhance consent comprehension and facilitate the research workflow. After multidisciplinary analysis in key hospital registration areas and research participant enrollment, an open source software product was designed to capture this data through a user-friendly touch screen interface. The data may then be fed into a clinical data warehouse for use in cohort discovery or consent tracking. Despite ethical, legal and informatics challenges in clinical and research environments, we propose that this technology opens new avenues for significantly enhancing the consent process and positively impacting recruitment.

  13. Continuous and immediate method for the detection of SF/sub 6/ and other tracer gases by electron capture in atmospheric diffusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, E.L. (Aerosol Lab., Risoe, Denmark); Lovelock, J.E.

    1976-01-01

    In many atmospheric diffusion experiments using tracer gases continuous tracer recording is of decisive importance. The main obstacle to continuous electron capture detection of tracer gases in the atmosphere is presented by the oxygen, which is an electron capturer. A method for removing this difficulty is described. Its practical use in an airborne atmospheric plume diffusion experiment is demonstrated.

  14. A coupled deterministic/stochastic method for computing neutron capture therapy dose rates

    Science.gov (United States)

    Hubbard, Thomas Richard

    Neutron capture therapy (NCT) is an experimental method of treating brain tumors and other cancers by: (1) injecting or infusing the patient with a tumor-seeking, neutron target-labeled drug; and (2) irradiating the patient in an intense epithermal neutron fluence. The nuclear reaction between the neutrons and the target nuclei (e.g. sp{10}B(n,alpha)sp7Lirbrack releases energy in the form of high-LET (i.e. energy deposited within the range of a cell diameter) reaction particles which selectively kill the tumor cell. The efficacy of NCT is partly dependent on the delivery of maximum thermal neutron fluence to the tumor and the minimization of radiation dose to healthy tissue. Since the filtered neutron source (e.g. research reactor) usually provides a broad energy spectrum of highly-penetrating neutron and gamma-photon radiation, detailed transport calculations are necessary in order to plan treatments that use optimal treatment facility configurations and patient positioning. Current computational methods for NCT use either discrete ordinates calculation or, more often, Monte Carlo simulation to predict neutron fluences in the vicinity of the tumor. These methods do not, however, accurately calculate the transport of radiation throughout the entire facility or the deposition of dose in all the various parts of the body due to shortcomings of using either method alone. A computational method, specifically designed for NCT problems, has been adapted from the MASH methodology and couples a forward discrete ordinates (Ssb{n}) calculation with an adjoint Monte Carlo run to predict the dose at any point within the patient. The transport from the source through the filter/collimator is performed with a forward DORT run, and this is then coupled to adjoint MORSE results at a selected coupling parallelepiped which surrounds human phantom. Another routine was written to allow the user to generate the MORSE models at various angles and positions within the treatment room. The

  15. Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Pseudoscalar Coupling $g_P$

    CERN Document Server

    Andreev, V A; Case, T A; Chitwood, D B; Clayton, S M; Crowe, K M; Deutsch, J; Egger, J; Freedman, S J; Ganzha, V A; Gorringe, T; Gray, F E; Hertzog, D W; Hildebrandt, M; Kammel, P; Kiburg, B; Knaack, S; Kravtsov, P A; Krivshich, A G; Lauss, B; Lynch, K L; Maev, E M; Maev, O E; Mulhauser, F; Özben, C S; Petitjean, C; Petrov, G E; Prieels, R; Schapkin, G N; Semenchuk, G G; Soroka, M A; Tishchenko, V; Vasilyev, A A; Vorobyov, A A; Vznuzdaev, M E; Winter, P

    2007-01-01

    The rate of nuclear muon capture by the proton has been measured using a new experimental technique based on a time projection chamber operating in ultra-clean, deuterium-depleted hydrogen gas at 1 MPa pressure. The capture rate was obtained from the difference between the measured $\\mu^-$ disappearance rate in hydrogen and the world average for the $\\mu^+$ decay rate. The target's low gas density of 1% compared to liquid hydrogen is key to avoiding uncertainties that arise from the formation of muonic molecules. The capture rate from the hyperfine singlet ground state of the $\\mu p$ atom is measured to be $\\Lambda_S=725.0 \\pm 17.4 s^{-1}$, from which the induced pseudoscalar coupling of the nucleon, $g_P(q^2=-0.88 m_\\mu^2)=7.3 \\pm 1.1$, is extracted. This result is consistent with theoretical predictions for $g_P$ that are based on the approximate chiral symmetry of QCD.

  16. Excited states in 168Yb from electron-capture decay of 168Lum (T1/2=6.7 min)

    Science.gov (United States)

    Barci, V.; Ardisson, G.; Trubert, D.; Hussonnois, M.

    1999-08-01

    The electron-capture decay of the 168Lum (T1/2=6.7 min, Jπ=3+) isomer was studied with high purity sources, obtained by using a new radiochemical method consisting of fast continous on-line separation of reaction products. A complex spectrum composed of about 200 γ rays was observed. From these, 162 transitions were assigned to a level scheme of 39 excited levels of 168Yb, primarily by γ-γ coincidence spectroscopic measurements. About 60 transitions were placed for the first time and >90% of the decay intensity was clearly identified. The structure of the levels directly fed by the electron-capture decay was reviewed as particle-hole excitations of the core.

  17. A data capture system for outcomes studies that integrates with electronic health records: development and potential uses.

    Science.gov (United States)

    Yamamoto, Keiichi; Matsumoto, Shigemi; Tada, Harue; Yanagihara, Kazuhiro; Teramukai, Satoshi; Takemura, Tadamasa; Fukushima, Masanori

    2008-10-01

    In conventional clinical studies, the costs of data management for quality control tend to be high and collecting paper-based case report forms (CRFs) tends to be burdensome, because paper-based CRFs must be developed and filled out for each clinical study protocol. Use of electronic health records for this purpose could result in reductions in cost and improvements in data quality in clinical studies. The purpose of this study was to develop a data capture system for observational cancer clinical studies (i.e. outcomes studies) that would integrate with an electronic health records system, to enable evaluation of patient prognosis, prognostic factors, outcomes and drug safety. At the Outpatient Oncology Unit of Kyoto University Hospital, we developed a data capture system that includes a cancer clinical database system and a data warehouse for outcomes studies. We expect that our new system will reduce the costs of data management and analysis and improve the quality of data in clinical studies.

  18. Experimental test of higher-order electron-capture processes in collisions of fast protons with atomic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, H.; Schuch, R.; Justiniano, E.; Schulz, M.; Schwab, W.

    1986-11-03

    We present measurements of the angular distribution of fast hydrogen atoms formed by electron capture of 2.8- and 5.0-MeV protons in atomic hydrogen. In the angular region of the Thomas peak (0.47 mrad) the experimental results obtained with this pure three-body collision system are in reasonable agreement with a strong potential Born calculation and the impulse approximation, but not with other higher-order theories.

  19. Experimental validation of calculated capture rate for nucleus involved in fuel cycle; Validation experimentale du calcul du taux de capture des noyaux intervenant dans le cycle du combustible

    Energy Technology Data Exchange (ETDEWEB)

    Benslimane-Bouland, A

    1997-09-01

    The framework of this study was the evaluation of the nuclear data requirements for Actinides and Fission Products applied to current nuclear reactors as well as future applications. This last item includes extended irradiation campaigns, 100 % Mixed Oxide fuel, transmutation or even incineration. The first part of this study presents different types of integral measurements which are available for capture rate measurements, as well as the methods used for reactor core calculation route design and nuclear data library validation. The second section concerns the analysis of three specific irradiation experiments. The results have shown the extent of the current knowledge on nuclear data as well as the associated uncertainties. The third and last section shows both the coherency between all the results, and the statistical method applied for nuclear data library adjustment. A relevant application of this method has demonstrated that only specifically chosen integral experiments can be of use for the validation of nuclear data libraries. The conclusion is reached that even if co-ordinated efforts between reactor and nuclear physicists have made possible a huge improvement in the knowledge of capture cross sections of the main nuclei such as uranium and plutonium, some improvements are currently necessary for the minor actinides (Np, Am and Cm). Both integral and differential measurements are recommended to improve the knowledge of minor actinide cross sections. As far as integral experiments are concerned, a set of criteria to be followed during the experimental conception have been defined in order to both reduce the number of required calculation approximations, and to increase as much as possible the maximum amount of extracted information. (author)

  20. Electron transfer by excited benzoquinone anions: slow rates for two-electron transitions.

    Science.gov (United States)

    Zamadar, Matibur; Cook, Andrew R; Lewandowska-Andralojc, Anna; Holroyd, Richard; Jiang, Yan; Bikalis, Jin; Miller, John R

    2013-09-05

    Electron transfer (ET) rate constants from the lowest excited state of the radical anion of benzoquinone, BQ(-•)*, were measured in THF solution. Rate constants for bimolecular electron transfer reactions typically reach the diffusion-controlled limit when the free-energy change, ΔG°, reaches -0.3 eV. The rate constants for ET from BQ(-•)* are one-to-two decades smaller at this energy and do not reach the diffusion-controlled limit until -ΔG° is 1.5-2.0 eV. The rates are so slow probably because a second electron must also undergo a transition to make use of the energy of the excited state. Similarly, ET, from solvated electrons to neutral BQ to form the lowest excited state, is slow, while fast ET is observed at a higher excited state, which can be populated in a transition involving only one electron. A simple picture based on perturbation theory can roughly account for the control of electron transfer by the need for transition of a second electron. The picture also explains how extra driving force (-ΔG°) can restore fast rates of electron transfer.

  1. Capture cross-section and rate of the 14C(, )15C reaction from the Coulomb dissociation of 15C

    Indian Academy of Sciences (India)

    Shubhchintak; Neelam; R Chatterjee

    2014-10-01

    We calculate the Coulomb dissociation of 15C on a Pb target at 68 MeV/u incident beam energy within the fully quantum mechanical distorted wave Born approximation formalism of breakup reactions. The capture cross-section and the subsequent rate of the 14C(, )15C reaction are calculated from the photodisintegration of 15C, using the principle of detailed balance. Our theoretical model is free from the uncertainties associated with the multipole strength distributions of the projectile.

  2. A New Insight into Neutrino Energy Loss by Electron Capture of Iron Group Nuclei in Magnetar Surfaces

    Science.gov (United States)

    Liu, Jing-Jing; Gu, Wei-Min

    2016-06-01

    Based on the relativistic mean-field effective interactions theory, and the Lai dong model, we discuss the influences of superstrong magnetic fields (SMFs) on electron Fermi energy, nuclear blinding energy, and single-particle level structure in magnetar surfaces. Using the Shell-Model Monte Carlo method and the Random Phase Approximation theory, we analyze the neutrino energy loss rates (NELRs) by electron capture for iron group nuclei in SMFs. First, when B 12 100, the NELRs decrease by more than three orders of magnitude (e.g., at T 9 = 15.53 for 52-61Fe, 55-60Co, and 56-63Ni). Second, for a certain value of magnetic field and temperature, the NELRs increase by more than four orders of magnitude when {ρ }7≤slant {10}3, but as the density increases (i.e., when {ρ }7\\gt {10}3), there is almost no influence on the density of NELRs. For the density around {ρ }7={10}2, there is an abrupt increase in NELRs when B 12 ≥ 103.5. Such jumps are an indication that the underlying shell structure has changed due to single-particle behavior by SMFs. Finally, we compare our NELRs with those of Fuller et al. (FFN) and Nabi & Klapdor-Kleingrothaus (NKK). For the case without SMFs, one finds that our rates for certain nuclei are close to about five orders of magnitude lower than FFN and NKK at relativistic low temperatures (e.g., T 9 = 1). However, at a relativistic high temperature (e.g., T 9 = 3), our results are in good agreement with NKK, but about one order of magnitude lower than FFN. For the case with SMFs, our NELRs for some iron group nuclei can be about five orders of magnitude higher than those of FFN and NKK. (Note that B 12, T 9, and ρ 7 are in units of 1012 G, 109 K, and {10}7 {{g}} {{cm}}-3, respectively.)

  3. Ionization and electron-capture cross sections for single- and multiple-electron removal from H2O by Li3 + impact

    Science.gov (United States)

    Luna, H.; Wolff, W.; Montenegro, E. C.; Tavares, André C.; Lüdde, H. J.; Schenk, G.; Horbatsch, M.; Kirchner, T.

    2016-05-01

    In this work, we report experimental and theoretical ionization and electron-capture cross sections for single-, double- and triple-electron removal from H2O by Li3 + impact at energies ranging from 0.75 to 5.8 MeV. The experiment was carried out by selecting both the final charge state of the projectile and the ejected fragments in coincidence to obtain cross sections associated with ionization and electron-capture channels. The ionic fragments and the emitted electrons produced under single-collision conditions were collected by a time-of-flight spectrometer with single-hit (e.g., OH++H0 ) and double-hit events (e.g., OH++H+ ) properly discriminated. For the one- and two-electron removal cases, the calculations based on the basis generator method for orbital propagation agree well with the experiment for most of the collision channels studied. Auger-electron emission after vacancy production in the inner 2 a1 orbital of H2O is shown to have a substantial effect on the final charge-state distributions over the entire impact-energy interval.

  4. Electron transfer rates and equilibrium within cytochrome c oxidase

    DEFF Research Database (Denmark)

    Farver, O; Einarsdóttir, O; Pecht, I

    2000-01-01

    identical within experimental error and independent of the enzyme concentration. This demonstrates that a fast intramolecular electron equilibration is taking place between CuA and heme a. The rate constants for CuA --> heme a ET and the reverse (heme a --> CuA) process were found to be 13 000 s-1 and 3700......Intramolecular electron transfer (ET) between the CuA center and heme a in bovine cytochrome c oxidase was investigated by pulse radiolysis. CuA, the initial electron acceptor, was reduced by 1-methyl nicotinamide radicals in a diffusion-controlled reaction, as monitored by absorption changes...... at 830 nm. After the initial reduction phase, the 830 nm absorption was partially restored, corresponding to reoxidation of the CuA center. Concomitantly, the absorption at 445 nm and 605 nm increased, indicating reduction of heme a. The rate constants for heme a reduction and CuA reoxidation were...

  5. Channeling, volume reflection, and volume capture study of electrons in a bent silicon crystal

    DEFF Research Database (Denmark)

    Wistisen, T. N.; Uggerhoj, U. I.; Wienands, U.;

    2016-01-01

    We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating the processes of channeling, volume-reflection and volume-capture along the (111) plane in a strongly bent quasimosaic silicon crystal. These phenomena were investigated at...

  6. 77 FR 4059 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof; Receipt...

    Science.gov (United States)

    2012-01-26

    ... for capturing and transmitting images, and components thereof. The complaint names Apple Inc. of Cupertino, CA; High Tech Computer Corp. (a/k/a HTC Corp.) of Taiwan; HTC America, Inc. of Bellevue, WA; and Exedea, Inc. of Houston, TX, as respondents. The complainant, proposed respondents, other...

  7. An Electronic Timer for Measuring Spread Rates of Wildland Fires

    Science.gov (United States)

    Richard W. Blank; Albert J. Simard

    1983-01-01

    There are many disadvantages to current techniques for measuring the spread rate of wildland fires. This paper describes the design and use of an electronic timber that resolves most of the problems. The unit is small, lightweight, inexpensive, easy-to-assemble, self-contained, and long-running.

  8. Capturing enveloped viruses on affinity grids for downstream cryo-electron microscopy applications

    Science.gov (United States)

    Electron microscopy cryo-electron microscopy and cryo-electron tomography are essential techniques used for characterizing basic virus morphology and determining the three-dimensional structure of viruses. Enveloped viruses, which contain an outer lipoprotein coat, constitute the largest group of pa...

  9. Modelling the effects of prey size and distribution on prey capture rates of two sympatric marine predators.

    Directory of Open Access Journals (Sweden)

    Chris B Thaxter

    Full Text Available Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge and razorbill (Alca torda during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bio-energetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5 ± 0.8 items per dive (0.8 ± 0.4 and 1.1 ± 0.6 items per minute foraging and underwater, respectively for guillemots and 3.7 ± 2.4 items per dive (4.9 ± 3.1 and 7.3 ± 4.0 items per minute foraging and underwater, respectively for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus length (prediction 1, but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2, and lower in prey density (prediction 3. Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6, thus not supporting prediction 3. This bio-energetics approach complements other foraging models

  10. Modelling the effects of prey size and distribution on prey capture rates of two sympatric marine predators.

    Science.gov (United States)

    Thaxter, Chris B; Daunt, Francis; Grémillet, David; Harris, Mike P; Benvenuti, Silvano; Watanuki, Yutaka; Hamer, Keith C; Wanless, Sarah

    2013-01-01

    Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge) and razorbill (Alca torda) during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bio-energetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5 ± 0.8 items per dive (0.8 ± 0.4 and 1.1 ± 0.6 items per minute foraging and underwater, respectively) for guillemots and 3.7 ± 2.4 items per dive (4.9 ± 3.1 and 7.3 ± 4.0 items per minute foraging and underwater, respectively) for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus) length (prediction 1), but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2), and lower in prey density (prediction 3). Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6), thus not supporting prediction 3. This bio-energetics approach complements other foraging models in

  11. Modelling the Effects of Prey Size and Distribution on Prey Capture Rates of Two Sympatric Marine Predators

    Science.gov (United States)

    Thaxter, Chris B.; Daunt, Francis; Grémillet, David; Harris, Mike P.; Benvenuti, Silvano; Watanuki, Yutaka; Hamer, Keith C.; Wanless, Sarah

    2013-01-01

    Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge) and razorbill (Alca torda) during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bio-energetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5±0.8 items per dive (0.8±0.4 and 1.1±0.6 items per minute foraging and underwater, respectively) for guillemots and 3.7±2.4 items per dive (4.9±3.1 and 7.3±4.0 items per minute foraging and underwater, respectively) for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus) length (prediction 1), but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2), and lower in prey density (prediction 3). Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6), thus not supporting prediction 3. This bio-energetics approach complements other foraging models in predicting likely

  12. Neutron-capture rates for explosive nucleosynthesis: the case of 68Ni(n, γ)69Ni

    Science.gov (United States)

    Spyrou, A.; Larsen, A. C.; Liddick, S. N.; Naqvi, F.; Crider, B. P.; Dombos, A. C.; Guttormsen, M.; Bleuel, D. L.; Couture, A.; Crespo Campo, L.; Lewis, R.; Mosby, S.; Mumpower, M. R.; Perdikakis, G.; Prokop, C. J.; Quinn, S. J.; Renstrøm, T.; Siem, S.; Surman, R.

    2017-04-01

    Neutron-capture reactions play an important role in heavy element nucleosynthesis, since they are the driving force for the two processes that create the vast majority of the heavy elements. When a neutron capture occurs on a short-lived nucleus, it is extremely challenging to study the reaction directly and therefore the use of indirect techniques is essential. The present work reports on such an indirect measurement that provides strong constraints on the 68Ni(n, γ)69Ni reaction rate. This is done by populating the compound nucleus 69Ni via the β decay of 69Co and measuring the γ-ray deexcitation of excited states in 69Ni. The β-Oslo method was used to extract the γ-ray strength function and the nuclear level density. In addition the half-life of 69Co was extracted and found to be in agreement with previous literature values. Before the present results, the 68Ni(n, γ)69Ni reaction was unconstrained and the purely theoretical reaction rate was highly uncertain. The new uncertainty on the reaction rate based on the present experiment (variation between upper and lower limit) is approximately a factor of 3. The commonly used reaction libraries JINA-REACLIB and BRUSLIB are in relatively good agreement with the experimental rate. The impact of the new rate on weak r-process calculations is discussed.

  13. Electron attachment rate constant measurement by photoemission electron attachment ion mobility spectrometry (PE-EA-IMS)

    Science.gov (United States)

    Su, Desheng; Niu, Wenqi; Liu, Sheng; Shen, Chengyin; Huang, Chaoqun; Wang, Hongmei; Jiang, Haihe; Chu, Yannan

    2012-12-01

    Photoemission electron attachment ion mobility spectrometry (PE-EA-IMS), with a source of photoelectrons induced by vacuum ultraviolet radiation on a metal surface, has been developed to study electron attachment reaction at atmospheric pressure using nitrogen as the buffer gas. Based on the negative ion mobility spectra, the rate constants for electron attachment to tetrachloromethane and chloroform were measured at ambient temperature as a function of the average electron energy in the range from 0.29 to 0.96 eV. The experimental results are in good agreement with the data reported in the literature.

  14. Relativistic collision rate calculations for electron-air interactions

    Energy Technology Data Exchange (ETDEWEB)

    Graham, G. [EG and G Energy Measurements, Inc., Los Alamos, NM (United States); Roussel-Dupre, R. [Los Alamos National Lab., NM (United States). Space Science and Technologies

    1992-12-16

    The most recent data available on differential cross sections for electron-air interactions are used to calculate the avalanche, momentum transfer, and energy loss rates that enter into the fluid equations. Data for the important elastic, inelastic, and ionizing processes are generally available out to electron energies of 1--10 kev. Prescriptions for extending these cross sections to the relativistic regime are presented. The angular dependence of the cross sections is included where data is available as is the doubly differential cross section for ionizing collisions. The collision rates are computed by taking moments of the Boltzmann collision integrals with the assumption that the electron momentum distribution function is given by the Juettner distribution function which satisfies the relativistic H- theorem and which reduces to the familiar Maxwellian velocity distribution in the nonrelativistic regime. The distribution function is parameterized in terms of the electron density, mean momentum, and thermal energy and the rates are therefore computed on a two-dimensional grid as a function of mean kinetic energy and thermal energy.

  15. Total cross sections for electron capture and transfer ionization by highly stripped, slow Ne, Ar, Kr, and Xe projectiles on helium

    Energy Technology Data Exchange (ETDEWEB)

    Justiniano, E.; Cocke, C.L.; Gray, T.J.; Dubois, R.; Can, C.; Waggoner, W.; Schuch, R.; Schmidt-Boecking, H.; Ingwersen, H.

    1984-03-01

    Experimental cross sections are reported for electron capture and transfer ionization for Ne, Ar, Kr, and Xe projectiles on He for charge states (q) between 2 and 13 and for projectile energies between (250 and 1000 eV)q. The double-electron capture is found to be typically an order of magnitude weaker than single-electron capture, and to be dominated in most cases by the transfer ionization channel. While gross features of the cross sections can be qualitatively understood, quantitative agreement with available theoretical model calculations is poor.

  16. Single-electron capture for 2-8 keV incident energy and direct scattering at 6 keV in He[sup 2+]-He collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, D.; Dagnac, R. (Toulouse-3 Univ., 31 (France). Centre de Physique Atomique)

    1992-06-14

    We studied the single-electron capture as well as the direct processes occurring when a He[sup 2+] ion is scattered by a He target. Doubly differential cross sections were measured for single-electron capture with a collision energy ranging from 2 to 8 keV and a scattering angle varying from 10' to 3[sup o]30' (laboratory frame). Single-electron capture into excited states of He[sup +] was found to be the dominant process, confirming a previous experimental study. Elastic scattering and ionization differential cross sections were measured for E = 6 keV. (Author).

  17. The feasibility of using 'bring your own device' (BYOD) technology for electronic data capture in multicentre medical audit and research.

    Science.gov (United States)

    Faulds, M C; Bauchmuller, K; Miller, D; Rosser, J H; Shuker, K; Wrench, I; Wilson, P; Mills, G H

    2016-01-01

    Large-scale audit and research projects demand robust, efficient systems for accurate data collection, handling and analysis. We utilised a multiplatform 'bring your own device' (BYOD) electronic data collection app to capture observational audit data on theatre efficiency across seven hospital Trusts in South Yorkshire in June-August 2013. None of the participating hospitals had a dedicated information governance policy for bring your own device. Data were collected by 17 investigators for 392 individual theatre lists, capturing 14,148 individual data points, 12, 852 (91%) of which were transmitted to a central database on the day of collection without any loss of data. BYOD technology enabled accurate collection of a large volume of secure data across multiple NHS organisations over a short period of time. Bring your own device technology provides a method for collecting real-time audit, research and quality improvement data within healthcare systems without compromising patient data protection.

  18. Double capture in the O/sup 8+/ + He collision investigated by electron spectroscopy (80 keV, 10 deg)

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Boudjema, M.; Gleizes, A.; Oza, D.H.; Dousson, S.; Hitz, D.

    1989-01-28

    Double capture into (3,n) autoionising states of O/sup 6+/ is observed in the O/sup 8+/ + He collision system by electron spectroscopy at 80 keV, 10/sup 0/. A comparison of the experimental results with theoretical positions and lifetimes allows the (3,3) states as well as three groups of (3,4) states to be identified. The present experimental findings are compared with earlier data for the N/sup 7+/ + He and Ne/sup 8+/(1s/sup 2/) + He systems. The influence of the core of the multicharged ion is studied by examining the O/sup 8+/ and Ne/sup 8+/(1s/sup 2/) results. The total double capture cross section is found to be large and it is compared with available experimental and theoretical data.

  19. Search for Perturbations of Nuclear Decay Rates Induced by Reactor Electron Antineutrinos

    CERN Document Server

    Barnes, V E; Bryan, C D; Cinko, N; Deichert, G G; Gruenwald, J T; Heim, J M; Kaplan, H B; LaZur, R; Neff, D; Nistor, J M; Sahelijo, N; Fischbach, E

    2016-01-01

    We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge National Laboratory, designed to address the question of whether a flux of reactor-generated electron antineutrinos can alter the rates of weak nuclear interaction-induced decays for Mn-54, Na-22, and Co-60. This experiment, while quite sensitive, cannot exclude perturbations less than one or two parts in $10^4$ in $\\beta$ decay (or electron capture) processes, in the presence of an antineutrino flux of $3\\times 10^{12}$ cm$^{-2}$ s$^{-1}$. The present experimental methods are applicable to a wide range of isotopes. Improved sensitivity in future experiments may be possible if we can understand and reduce the dominant systematic uncertainties.

  20. ELECTRON-CAPTURE IN HIGHLY-CHARGED ION-ATOM COLLISIONS

    NARCIS (Netherlands)

    MORGENSTERN, R

    1993-01-01

    An attempt is made to identify the most important mechanisms responsible for the rearrangement of electrons during collisions between multiply charged ions and atoms at keV energies. It is discussed to which extent the influence of binding energy, angular momentum of heavy particles and electrons, a

  1. ELECTRON-CAPTURE IN HIGHLY-CHARGED ION-ATOM COLLISIONS

    NARCIS (Netherlands)

    MORGENSTERN, R

    1993-01-01

    An attempt is made to identify the most important mechanisms responsible for the rearrangement of electrons during collisions between multiply charged ions and atoms at keV energies. It is discussed to which extent the influence of binding energy, angular momentum of heavy particles and electrons,

  2. Analysis of neonicotinoids by gas chromatography coupled to nuclide {sup 63}Ni - Electron Capture Detector - GC/ECD

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Priscila O.; Leao, Claudio; Redigolo, Marcelo M.; Crepaldi, Caike; Bustillos, Oscar V., E-mail: priscilaoamaral@gmail.com, E-mail: claudio.leao@usp.br, E-mail: marceloredigolo@gmail.com, E-mail: caike1995@gmail.com, E-mail: ovega@ipen.bremails [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Recently, several reports have been published discussing reduction in bee population which polymerizes cultures around the world this phenomenon is known as Colony Collapse Disorder (CCD). The phenomenon describes the lack of worker honeybees in the colony despite having pups and food. The causes of this problem are unknown but there are studies that claim that reduction of population of bees is linked to poisoning through insecticides specifically neonicotinoids. Among this type of pesticide are imidacloprid (C{sub 9}H{sub 10}ClN{sub 5}O{sub 2}), clothianidin (C{sub 6}H{sub 8}ClN{sub 5}O{sub 2}S) and thiamethoxam (C{sub 8}H{sub 10}ClN{sub 5}O{sub 3}S). This paper presents the analysis of neonicotinoids - clothianidin, imidacloprid and thiamethoxam - by the technique of gas chromatography coupled to nuclide {sup 63}Ni electron capture detector (GC/ECD). The electron capture detector (ECD) is a gas chromatography detector that has been used for the detection of organic halogens, nitriles, nitrates and organometallic compounds. The ECD detector ionizes the analytes by the beta particles from the nuclide sources {sup 63}Ni within carrier gas N{sub 2}. The electrons produced in this process are collected and create a current that are amplified and generates a chromatographic peak. Methodology and details of the analysis are present in this work. (author)

  3. Capturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator

    Science.gov (United States)

    He, Z.-H.; Beaurepaire, B.; Nees, J. A.; Gallé, G.; Scott, S. A.; Pérez, J. R. Sánchez; Lagally, M. G.; Krushelnick, K.; Thomas, A. G. R.; Faure, J.

    2016-11-01

    Recent progress in laser wakefield acceleration has led to the emergence of a new generation of electron and X-ray sources that may have enormous benefits for ultrafast science. These novel sources promise to become indispensable tools for the investigation of structural dynamics on the femtosecond time scale, with spatial resolution on the atomic scale. Here, we demonstrate the use of laser-wakefield-accelerated electron bunches for time-resolved electron diffraction measurements of the structural dynamics of single-crystal silicon nano-membranes pumped by an ultrafast laser pulse. In our proof-of-concept study, we resolve the silicon lattice dynamics on a picosecond time scale by deflecting the momentum-time correlated electrons in the diffraction peaks with a static magnetic field to obtain the time-dependent diffraction efficiency. Further improvements may lead to femtosecond temporal resolution, with negligible pump-probe jitter being possible with future laser-wakefield-accelerator ultrafast-electron-diffraction schemes.

  4. Capturing Structural Dynamics in Crystalline Silicon Using Chirped Electrons from a Laser Wakefield Accelerator

    CERN Document Server

    He, Z -H; Nees, J A; Gallé, G; Scott, S A; Pérez, J R Sanchez; Lagally, M G; Krushelnick, K; Thomas, A G R; Faure, J

    2016-01-01

    Recent progress in laser wakefield acceleration has led to the emergence of a new generation of electron and X-ray sources that may have enormous benefits for ultrafast science. These novel sources promise to become indispensable tools for the investigation of structural dynamics on the femtosecond time scale, with spatial resolution on the atomic scale. Here, we demonstrate the use of laser-wakefield-accelerated electron bunches for time-resolved electron diffraction measurements of the structural dynamics of single-crystal silicon nano-membranes pumped by an ultrafast laser pulse. In our proof-of-concept study, we resolve the silicon lattice dynamics on a picosecond time scale by deflecting the momentum-time correlated electrons in the diffraction peaks with a static magnetic field to obtain the time-dependent diffraction efficiency. Further improvements may lead to femtosecond temporal resolution, with negligible pump-probe jitter being possible with future laser-wakefield-accelerator ultrafast-electron-di...

  5. Monitoring oral temperature, heart rate, and respiration rate of West Indian manatees (Trichechus manatus) during capture and handling in the field

    Science.gov (United States)

    Wong, Arthur W.; Bonde, Robert K.; Siegal-Willott, Jessica; Stamper, M. Andrew; Colee, James; Powell, James A.; Reid, James P.; Deutsch, Charles J.; Harr, Kendal E.

    2012-01-01

    West Indian manatees (Trichechus manatus) are captured, handled, and transported to facilitate conservation, research, and rehabilitation efforts. Monitoring manatee oral temperature (OT), heart rate (HR), and respiration rate (RR) during out-of-water handling can assist efforts to maintain animal well-being and improve medical response to evidence of declining health. To determine effects of capture on manatee vital signs, we monitored OT, HR, and RR continuously for a 50-min period in 38 healthy, awake, juvenile and adult Florida manatees (T. m. latirostris) and 48 similar Antillean manatees (T. m. manatus). We examined creatine kinase (CK), potassium (K+), serum amyloid A (SAA), and lactate values for each animal to assess possible systemic inflammation and muscular trauma. OT range was 29.5 to 36.2° C, HR range was 32 to 88 beats/min, and RR range was 0 to 17 breaths/5 min. Antillean manatees had higher initial OT, HR, and RR than Florida manatees (p manatees had higher overall lactate values ([mean ± SD] 20.6 ± 7.8 mmol/L) than Florida manatees (13.7 ± 6.7 mmol/L; p manatee OT, HR, and RR during capture and handling in the field or in a captive care setting.

  6. Core-electron effect in state-selective electron capture collisions of highly charged ions with alkali-metal atom targets

    Energy Technology Data Exchange (ETDEWEB)

    Pascale, J. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Recherche sur l`Etat Condense, les Atomes et les Molecules; Jacquet, E. [Caen Univ., 14 (France). Lab. de Spectroscopie Atomique

    1994-12-31

    We study both experimentally and theoretically the influence of the projectile core electrons on the single electron capture process, in medium-energy collisions of partially stripped ions with ground-state alkali-metal atom targets. The effect is clearly demonstrated in the final nl-distributions of the capture electron in Ar{sup 8+} - and Kr{sup 8+} - Li(2s) collisions, by comparisons of experimental data with three-body classical trajectory Monte-Carlo (CTMC) calculations performed for these ions, and also for Ne{sup 8+} and O{sup 8+}. The effect manifests itself by a significant population of low l-values which does not show up in the case of fully or nearly fully stripped ions; it is strongly energy dependent and vanishes at high energies. The CTMC calculations show also a clear influence of the core electrons on the m-distribution of a given final n-level. (authors). 15 refs., 4 figs., 2 tabs.

  7. Muon capture at PSI

    CERN Document Server

    Winter, Peter

    2010-01-01

    Measuring the rate of muon capture in hydrogen provides one of the most direct ways to study the axial current of the nucleon. The MuCap experiment uses a negative muon beam stopped in a time projection chamber operated with ultra-pure hydrogen gas. Surrounded by a decay electron detector, the lifetime of muons in hydrogen can be measured to determine the singlet capture rate Lambda_s to a final precision of 1%. The capture rate determines the nucleon's pseudoscalar form factor g_p. A first result, g_p = 7.3 +- 1.1, has been published and the final analysis of the full statistics will reduce the error by a factor of up to 3. Muon capture on the deuteron probes the weak axial current in the two-nucleon system. Within the framework of effective field theories the calculation of such two-nucleon processes involving the axial current requires the knowledge of one additional low energy constant which can be extracted from the doublet capture rate Lambda_d. The same constant then allows to model-independently calcu...

  8. Influence of spatiotemporal coupling on the capture-and-acceleration-scenario vacuum electron acceleration by ultrashort pulsed laser beam

    Institute of Scientific and Technical Information of China (English)

    Lu Da-Quan; Qian Lie-Jia; Li Yong-Zhong; Fan Dian-Yuan

    2007-01-01

    This paper investigates the properties of the ultrashort pulsed beam aimed to the capture-and-acceleration-scenario(CAS) vacuum electron acceleration. The result shows that the spatiotemporal distribution of the phase velocity, the longitudinal component of the electric field and the acceleration quality factor are qualitatively similar to that of the continuous-wave Gaussian beam, and are slightly influenced by the spatiotemporal coupling of the ultrashort pulsed beam. When the pulse is compressed to an ultrashort one in which the pulse duration TFWHM < 5T0, the variation of the maximum net energy gain due to the carrier-envelope phase is a crucial disadvantage in the CAS acceleration process.

  9. Determination of chloramphenicol residue in fish and shrimp tissues by gas chromatography with a microcell electron capture detector.

    Science.gov (United States)

    Ding, Shuangyang; Shen, Jianzhong; Zhang, Suxia; Jiang, Haiyang; Sun, Zhiwen

    2005-01-01

    A gas chromatography method with microcell electron capture detection was developed for the determination of chloramphenicol residue in fish and shrimp muscle tissues. The tissue samples were extracted with ethyl acetate, defatted with hexane, and derivatized with Sylon BFT [N,O-bis (trimethylsilyl) trifluoroacetamide-trimethylchlorosilane (99 + 1)]. The limit of detection was 0.04 ng/g and the limit of quantitation 0.1 ng/g. Average recoveries were 70.8-90.8% for fish and 69.9-86.3% for shrimp, respectively. The method was validated for the determination of practical samples.

  10. State-selective electron capture in collisions of ground and metastable O{sup 2+} ions with H(1s)

    Energy Technology Data Exchange (ETDEWEB)

    Cabello, C N [Departamento de Quimica, Universidad Autonoma de Madrid, Madrid (Spain); Errea, L F [Departamento de Quimica, Universidad Autonoma de Madrid, Madrid (Spain); Fernandez, L [Departamento de Quimica, Universidad Autonoma de Madrid, Madrid (Spain); Mendez, L [Departamento de Quimica, Universidad Autonoma de Madrid, Madrid (Spain); Macias, A [Departamento de Quimica, Universidad Autonoma de Madrid, Madrid (Spain); Rabadan, I [Departamento de Quimica, Universidad Autonoma de Madrid, Madrid (Spain); Riera, A [Departamento de Quimica, Universidad Autonoma de Madrid, Madrid (Spain)

    2003-01-28

    An ab initio calculation of the electron capture cross sections for collisions of ground and metastable states of O{sup 2+} with H(1s) is presented. For impact energies between 0.125 and 3.4 keV amu{sup -1}, we find good agreement between the cross sections from the ground state ion with the mixed beam experimental data of Phaneuf et al (Phaneuf A, Alvarez I, Meyer F W and Crandall D H 1982 Phys. Rev. A 26 1892)

  11. Measurements of Fission and Radioactive Capture Reaction Rates Inside the Fuel of the Ipen/MB-01

    Science.gov (United States)

    Mura, Luís Felipe L.; Bitelli, Ulysses d'Utra; Fanaro, Leda C. C. B.

    2011-05-01

    This work presents the measures of the nuclear reaction rates along the radial direction of the fuel pellet by irradiation and posterior gamma spectrometry of a thin slice of fuel pellet of UO2 at 4.3% enrichment. From its irradiation, the rate of radioactive capture and fission had been measured as a function of the radius of the pellet disk using a Ortec GMX HPGe detector. Lead collimators had been used for this purpose. Simulating the fuel pellet in the pin fuel of the IPEN/MB-01 reactor, a thin UO2 disk is used, being inserted in the interior of a dismountable fuel rod. This fuel rod is then placed in the central position of the IPEN/MB-01 reactor core and irradiated during 1 h under a neutron flux of 5 ×108 n/cm2 s. In gamma spectrometry, 10 collimators with different diameters have been used; consequently, the nuclear reactions of radioactive capture that occurs in atoms of 238U and the fission that occurs on both 235U and 238U are measured in function of 10 different regions (diameter of collimator) of the UO2 fuel pellet disk. Nuclear fission produces different fission products such as 143Ce with a yield fission of 5.9% which decay is monitored in this work. Corrections in geometric efficiency due to introduction of collimators on HPGe detection system were estimated using photon transport of MCNP-4C code. Some calculated values of nuclear reaction rate of radioactive capture and fission along the radial direction of the fuel pellet obtained by Monte Carlo methodology, using the MCNP-4C code, are presented and compared to the experimental data showing very good agreement.

  12. Astrophysical Reaction Rates of the 8Li(p,γ)9Beg.s. Direct Capture Reaction

    Institute of Scientific and Technical Information of China (English)

    Su Jun; WANG You-Bao; LI Zhi-Hong; GUO Bing; LIU Wei-Ping; BAI Xi-Xiang; ZENG Sheng; LIAN Gang; YAN Sheng-Quan; WANG Bao-Xiang

    2006-01-01

    Based 0n the angular distribution of the 8Li(d,n)9Beg.s. reaction at Ec.m.=8.0 MeV and distorted wave Born approximation analysis,the single particle spectroscopic factor S1,3/2 for the ground state of 9Be=8Li(×)p is derived to be 0.64±0.21.In addition,we deduce the astrophysical S-factors and rates of the 8Li(p,γ)9Beg.s. direct capture reaction at energies of astrophysical interests.

  13. Capturing social and behavioral domains in electronic health records: Phase 1

    National Research Council Canada - National Science Library

    Board on Population Health and Public Health Practice; Institute of Medicine; Committee on the Recommended Social and Behavioral Domains and Measures for Electronic Health Records

    2014-01-01

    .... Electronic health records (EHRs) provide crucial information to providers treating individual patients, to health systems, including public health officials, about the health of populations, and to researchers about the determinants...

  14. Channeling, volume reflection, and volume capture study of electrons in a bent silicon crystal

    Science.gov (United States)

    Wistisen, T. N.; Uggerhøj, U. I.; Wienands, U.; Markiewicz, T. W.; Noble, R. J.; Benson, B. C.; Smith, T.; Bagli, E.; Bandiera, L.; Germogli, G.; Guidi, V.; Mazzolari, A.; Holtzapple, R.; Tucker, S.

    2016-07-01

    We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating the processes of channeling, volume-reflection and volume-capture along the (111) plane in a strongly bent quasimosaic silicon crystal. These phenomena were investigated at 5 energies: 3.35, 4.2, 6.3, 10.5, and 14.0 GeV with a crystal with bending radius of 0.15 m, corresponding to curvatures of 0.053, 0.066, 0.099, 0.16, and 0.22 times the critical curvature, respectively. Based on the parameters of fitting functions we have extracted important parameters describing the channeling process such as the dechanneling length, the angle of volume reflection, the surface transmission, and the widths of the distribution of channeled particles parallel and orthogonal to the plane.

  15. Mass measurements of neutron rich isotopes in the Fe region and electron capture processes in neutron star crusts

    Energy Technology Data Exchange (ETDEWEB)

    Estrade, Alfredo [National Superconducting Cyclotron Laboratory (NSCL); Matos, M. [Louisiana State University; Schatz, Hendrik [Michigan State University, East Lansing; Amthor, A. M. [National Superconducting Cyclotron Laboratory (NSCL); Beard, Mary [University of Notre Dame, IN; Brown, Edward [Michigan State University, East Lansing; Bazin, D. [National Superconducting Cyclotron Laboratory (NSCL); Becerril, A. [National Superconducting Cyclotron Laboratory (NSCL); Elliot, T [National Superconducting Cyclotron Laboratory (NSCL); Gade, A. [National Superconducting Cyclotron Laboratory (NSCL); Galaviz, D. [National Superconducting Cyclotron Laboratory (NSCL); Gupta, Sanjib [Indian Institute of Technology, Kanpur; Hix, William Raphael [ORNL; Lau, Rita [National Superconducting Cyclotron Laboratory (NSCL); Moeller, Peter [Los Alamos National Laboratory (LANL); Pereira, J. [National Superconducting Cyclotron Laboratory (NSCL); Portillo, M. [National Superconducting Cyclotron Laboratory (NSCL); Rogers, A. M. [National Superconducting Cyclotron Laboratory (NSCL); Shapira, Dan [ORNL; Smith, E. [Ohio State University; Stolz, A. [Michigan State University, East Lansing; Wallace, M. [Los Alamos National Laboratory (LANL); Wiescher, Michael [University of Notre Dame, IN

    2010-01-01

    Experimental knowledge of nuclear masses of exotic nuclei is important for understanding nu- clear structure far from the valley of -stability, and as a direct input into astrophysical models. Electron capture processes in the crust of accreting neutron stars have been proposed as a heat source that can affect the thermal structure of the star. Nuclear masses of very neutron-rich nu- clides are necessary inputs to model the electron capture process. The time-of-flight (TOF) mass measurement technique allows measurements on very short-lived nuclei. It has been effectively applied using the fast fragment beams produced at the National Superconducting Cyclotron Lab (NSCL) to reach masses very far from stability. Measurements were performed for neutron-rich isotopes in the region of the N=32 and N=40 subshells, which coincides with the mass range of carbon superburst ashes. We discuss reaction network calculations performed to investigate the impact of our new measurements and to compare the effect of using different global mass models in the calculations. It is observed that the process is sensitive to the differences in the odd-even mass staggering predicted by the mass models, and our new result for 66Mn has a significant impact on the distribution of heat sources in the crust.

  16. On the Significance of the Contribution of Multiple-Electron Capture Processes to Cometary X-Ray Emission

    Energy Technology Data Exchange (ETDEWEB)

    Ali, R; Neill, P A; Beiersdorfer, P; Harris, C L; Rakovi?, M J; Wang, J G; Schultz, D R; Stancil, P C

    2005-05-12

    We report laboratory studies of the role played by multiple-electron capture (MEC) in solar wind induced cometary X-ray emission. Collisions of Ne{sup 10+} with He, Ne, Ar, CO, and CO{sub 2} have been investigated by means of the traditional singles X-ray spectroscopy in addition to the triple-coincidence measurements of X-rays, scattered projectile, and target recoil ions for the atomic targets. The coincidence measurements enable the reduction of the singles X-ray spectra into partial spectra originating in single-electron capture (SEC) and MEC collisions. The measurements provide unequivocal evidence for a significant role played by MEC, and strongly suggest that models based solely on SEC are bound to yield erroneous conclusions on the solar wind composition and velocities and on cometary atmospheres. The experimental relative importance of MEC collisions is compared with molecular classical-over-the-barrier model (MCBM), classical trajectory Monte Carlo (CTMC), and multi-channel Landau-Zener (MCLZ), calculations which can qualitatively reproduce the experimental trends.

  17. Modularity and rates of evolutionary change in a power-amplified prey capture system.

    Science.gov (United States)

    Claverie, Thomas; Patek, S N

    2013-11-01

    The dynamic interplay among structure, function, and phylogeny form a classic triad of influences on the patterns and processes of biological diversification. Although these dynamics are widely recognized as important, quantitative analyses of their interactions have infrequently been applied to biomechanical systems. Here we analyze these factors using a fundamental biomechanical mechanism: power amplification. Power-amplified systems use springs and latches to generate extremely fast and powerful movements. This study focuses specifically on the power amplification mechanism in the fast raptorial appendages of mantis shrimp (Crustacea: Stomatopoda). Using geometric morphometric and phylogenetic comparative analyses, we measured evolutionary modularity and rates of morphological evolution of the raptorial appendage's biomechanical components. We found that "smashers" (hammer-shaped raptorial appendages) exhibit lower modularity and 10-fold slower rates of morphological change when compared to non-smashers (spear-shaped or undifferentiated appendages). The morphological and biomechanical integration of this system at a macroevolutionary scale and the presence of variable rates of evolution reveal a balance between structural constraints, functional variation, and the "roles of development and genetics" in evolutionary diversification. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  18. Electron-impact ionization rates for BF3 fragments

    Science.gov (United States)

    Vuskovic, L.; Raskovic, M.; Popovic, S.

    2007-06-01

    We calculated electron-impact ionization rates of BF3 and its fragments for electron energy distribution present in sheath mode of the repetitively pulsed d.c. diode system [1]. Data are being used for Ar/BF3 discharge modeling. BF3 and its fragments are reactive species that we are using to interact with niobium surface. The aim is to remove oxides and other impurities from the surface in the form of volatile compounds. This procedure of cleaning and smoothening improves the performance of the superconducting radiofrequency cavities used for particle accelerators. In our calculation electronic structures of BF3 and its fragments were described with several empirical basis sets. After geometry optimization using density functional method B3LYP, MO parameters were calculated with UHF, CCSD(T) and OVGF methods [2]. Electron-impact ionization cross-sections were calculated employing the Binary-Encounter-Bethe approximation. Cross-section results were compared with available experimental data. Relative calculation errors were estimated, which was especially important for cross-sections obtained with CEP-31G basis set that is necessary to describe system containing niobium samples. [1] S. Radovanov, et al., J. Appl. Phys. 98, 113307 (2005). [2] Y-K. Kim, K.K. Irikura, AIP conferences proceedings, 543, 220 (2000).

  19. Improving the Capture of Co2 by Substituted Monoethanolamines: Electronic Effects of Fluorine and Methyl Substituents

    NARCIS (Netherlands)

    Gangarapu, S.; Marcelis, A.T.M.; Zuilhof, H.

    2012-01-01

    The influence of electronic and steric effects on the reaction between CO(2) and monoethanolamine (MEA) absorbents is investigated using computational methods. The pK(a) of the alkanolamine, the reaction enthalpy for carbamate formation, and the hydrolytic carbamate stability are important factors f

  20. Multiple Electron Capture Processes in Slow Collisions of Ar9+ Ions with Na Atoms

    Institute of Scientific and Technical Information of China (English)

    ZhuXiaolong; ShaShan; LiuHuiping; WeiBaoren; MaXinwen; WangZhengling; CaoShiping; QianDongbing; YangZhihu

    2003-01-01

    Slow collisions of highly charged ions with neutral atoms and molecules are of great importance in basic atomic collision physics, Recently, we built a new research facility for atomic physics at the Institute of Modern Physics. We report here the multiple electron transfer processes in collisions of Ar9+ with Na gas target at energy of 180 keV.

  1. Dipole-Guided Electron Capture Causes Abnormal Dissociations of Phosphorylated Pentapeptides

    DEFF Research Database (Denmark)

    Moss, Christopher L.; Chung, Thomas W.; Wyer, Jean

    2011-01-01

    in ECD is explained by a distortion of the Rydberg orbital space by the strong dipolar field of the peptide dication framework. The dipolar field steers the incoming electron to preferentially attach to the positively charged arginine side chain to form guanidinium radicals and trigger...

  2. Study of high-pressure hydrogen-operated wire chambers designed for a precision measurement of the singlet mu p capture rate

    CERN Document Server

    Maev, E M; Case, T A; Crowe, K M; Dick, P U; Dijksman, A; Egger, J; Fetisov, A A; Ganzha, V A; Herold, W D; Hartmann, F J; Kammel, P; Krivchitch, A G; Maev, O E; Petitjean, C; Petrov, G E; Prieels, R; Sadetsky, S M; Schapkin, G N; Schmidt, R; Semenchuk, G G; Soroka, M; Vorobyov, A A; Voropaev, N I

    2002-01-01

    This work was carried out as part of a project aiming at a greatly improved measurement of the muon capture rate from the singlet state of the mu p atom. The experiment will be performed at the intense muon beam of PSI using a new experimental method allowing high precision measurements of the lifetime of muons stopped in ultra-pure deuterium-depleted hydrogen (protium). The basic element of the detector is a time projection chamber operating in hydrogen gas at 10 bar pressure. The arrival times and trajectories of the incoming muons and the outgoing decay electrons are measured with this device providing effective suppression of background. The system of chambers and electronics is designed for the large muon stop rates required for attaining high statistical accuracy. During four beam periods at PSI, data were taken. Also, various studies of the MWPC performance in hydrogen were made including ageing studies of the chambers under irradiation with stopped muons and with alpha and beta sources. It was demonst...

  3. Estimating Suicide Rates in Developing Nations: A Low-Cost Newspaper Capture-Recapture Approach in Cambodia.

    Science.gov (United States)

    Harris, Keith M; Thandrayen, Joanne; Samphoas, Chien; Se, Pros; Lewchalermwongse, Boontriga; Ratanashevorn, Rattanakorn; Perry, Megan L; Britts, Choloe

    2016-04-01

    This study tested a low-cost method for estimating suicide rates in developing nations that lack adequate statistics. Data comprised reported suicides from Cambodia's 2 largest newspapers. Capture-recapture modeling estimated a suicide rate of 3.8/100 000 (95% CI = 2.5-6.7) for 2012. That compares to World Health Organization estimates of 1.3 to 9.4/100 000 and a Cambodian government estimate of 3.5/100 000. Suicide rates of males were twice that of females, and rates of those newspaper reports proved a reasonable method for estimating suicide rates for countries with inadequate official data. These methods are low-cost and can be applied to regions with at least 2 newspapers with overlapping reports. Means to further improve this approach are discussed. These methods are applicable to both recent and historical data, which can benefit epidemiological work, and may also be applicable to homicides and other statistics.

  4. Investigation of the Mechanism of Electron Capture and Electron Transfer Dissociation of Peptides with a Covalently Attached Free Radical Hydrogen Atom Scavenger.

    Science.gov (United States)

    Sohn, Chang Ho; Yin, Sheng; Peng, Ivory; Loo, Joseph A; Beauchamp, J L

    2015-11-15

    The mechanisms of electron capture and electron transfer dissociation (ECD and ETD) are investigated by covalently attaching a free-radical hydrogen atom scavenger to a peptide. The 2,2,6,6-tetramethylpiperidin-l-oxyl (TEMPO) radical was chosen as the scavenger due to its high hydrogen atom affinity (ca. 280 kJ/mol) and low electron affinity (ca. 0.45 ev), and was derivatized to the model peptide, FQX(TEMPO)EEQQQTEDELQDK. The X(TEMPO) residue represents a cysteinyl residue derivatized with an acetamido-TEMPO group. The acetamide group without TEMPO was also examined as a control. The gas phase proton affinity (882 kJ/mol) of TEMPO is similar to backbone amide carbonyls (889 kJ/mol), minimizing perturbation to internal solvation and sites of protonation of the derivatized peptides. Collision induced dissociation (CID) of the TEMPO tagged peptide dication generated stable odd-electron b and y type ions without indication of any TEMPO radical induced fragmentation initiated by hydrogen abstraction. The type and abundance of fragment ions observed in the CID spectra of the TEMPO and acetamide tagged peptides are very similar. However, ECD of the TEMPO labeled peptide dication yielded no backbone cleavage. We propose that a labile hydrogen atom in the charge reduced radical ions is scavenged by the TEMPO radical moiety, resulting in inhibition of N-Cα backbone cleavage processes. Supplemental activation after electron attachment (ETcaD) and CID of the charge-reduced precursor ion generated by electron transfer of the TEMPO tagged peptide dication produced a series of b + H (b(H)) and y + H (y(H)) ions along with some c ions having suppressed intensities, consistent with stable O-H bond formation at the TEMPO group. In summary, the results indicate that ECD and ETD backbone cleavage processes are inhibited by scavenging of a labile hydrogen atom by the localized TEMPO radical moiety. This observation supports the conjecture that ECD and ETD processes involve long

  5. On the viability of heterolytic peptide N-C(α) bond cleavage in electron capture and transfer dissociation mass spectrometry.

    Science.gov (United States)

    Wodrich, Matthew D; Zhurov, Konstantin O; Corminboeuf, Clémence; Tsybin, Yury O

    2014-03-20

    While frequently employed as an experimental technique, the mechanistic picture surrounding the gas-phase dissociation of peptides carrying multiple positive charges during electron capture and electron transfer dissociation tandem mass spectrometry remains incomplete. Despite this mechanistic uncertainty, most proposals agree that the peptide backbone N-Cα bond located to the C-terminal (right) side of an aminoketyl radical formed in a peptide backbone during the electron capture process is homolytically cleaved. Recently, we introduced the "enol" mechanism, which proposes that a backbone N-Cα bond located to the N-terminal (left) side of an aminoketyl radical is cleaved heterolytically. Here, we further validate this mechanism using replica-exchange molecular dynamics to create unbiased representative sets of low-energy conformers for several model tryptic peptide systems (H-Alax-Lys-OH(2+), x = 3-5). Transition state barrier enthalpies for the cleavage of N-Cα bonds proceeding via the homolytic (right-side) and heterolytic (left-side) pathways, determined by density functional computations, identify the preferred cleavage route for each conformer. These findings support our original hypothesis that heterolytic N-Cα cleavage can exist in a competitive balance with homolytic cleavages, independent of the relative energy of the precursor dication species. Smaller peptide systems see decreased heterolytic N-Cα cleavage probabilities, likely resulting from an insufficient hydrogen-bonding network needed to stabilize and ultimately annihilate the transition state zwitterion. This observation may explain the early dismissal of left-side cleavage pathways based on computational studies employing small model systems.

  6. Structural determination of zinc dithiophosphates in lubricating oils by gas chromatography-mass spectrometry with electron impact and electron-capture negative ion chemical ionization.

    Science.gov (United States)

    Becchi, M; Perret, F; Carraze, B; Beziau, J F; Michel, J P

    2001-01-05

    Pentafluorobenzyl ester derivatives were used to identify zinc dialkyldithiophosphates and diaryldithiophosphates antiwear engine oil additives by GC-electron impact ionization (EI) MS and GC-electron-capture negative ion chemical ionization (ECNCI) MS analysis. GC-EI-MS of the dialkyldithiophosphate-pentafluorobenzyl derivatives afforded characteristic fragment ions corresponding to the cleavage of one and two alkyl radicals. In most cases, information was only obtained on one alkyl chain. Additional and complete information was obtained with retention time indices using synthetic derivatives and with GC-ECNCI-MS analysis. ECNCI afforded characteristic dithiophosphate anions which allowed the determination of the total number of carbon atoms in the alkyl radicals. The diastereoisomer mixtures of 2-hydroxy-sec.-alkyl radicals were completely separated on GC analysis.

  7. Stellar neutron capture rates – key data for the s process

    Directory of Open Access Journals (Sweden)

    Käppeler F.

    2013-12-01

    Full Text Available Neutron reactions are responsible for the formation of the elements heavier than iron. The corresponding scenarios relate to the He- and C- burning phases of stellar evolution (s process and to supernova explosions (r and p processes. The s process, which is characterized by low neutron densities, operates in or near the valley of β stability and has produced about half of the elemental abundances between Fe and Bi in the solar system and in the Universe. Because the s abundances are essentially determined by the (n, γ cross sections along the reaction path, accurate neutron data constitute the key input for s process studies. Important constraints for the physical conditions at the stellar sites can be inferred by comparison of the abundance patterns from current s-process models with solar system material or presolar grains. The experimental methods for the determination of stellar (n, γ rates are outlined at the example of recent cross section measurements and remaining quests will be discussed with respect to existing laboratory neutron sources and new developments.

  8. Capturing Age-group Differences and Developmental Change with the BASC Parent Rating Scales.

    Science.gov (United States)

    Barbot, Baptiste; Hein, Sascha; Luthar, Suniya S; Grigorenko, Elena L

    2014-07-01

    Estimation of age-group differences and intra-individual change across distinct developmental periods is often challenged by the use of age-appropriate (but non-parallel) measures. We present a short version of the Behavior Assessment System (Reynolds & Kamphaus, 1998), Parent Rating Scales for Children (PRS-C) and Adolescents (PRS-A), which uses only their common-items to derive estimates of the initial constructs optimized for developmental studies. Measurement invariance of a three-factor model (Externalizing, Internalizing, Adaptive Skills) was tested across age-groups (161 mothers using PRS-C; 200 mothers using PRS-A) and over time (115 mothers using PRS-C at baseline and PRS-A five years later) with the original versus short PRS. Results indicated that the short PRS holds a sufficient level of invariance for a robust estimation of age-group differences and intra-individual change, as compared to the original PRS, which held only weak invariance leading to flawed developmental inferences. Importance of test-content parallelism for developmental studies is discussed.

  9. Increasing capture efficiency of pallid sturgeon Scaphirhynchus albus (Forbes and Richardson, 1905) and the reliability of catch rate estimates

    Science.gov (United States)

    DeVries, R. J.; Hann, D. A.; Schramm, H.L.

    2015-01-01

    This study evaluated the effects of environmental parameters on the probability of capturing endangered pallid sturgeon (Scaphirhynchus albus) using trotlines in the lower Mississippi River. Pallid sturgeon were sampled by trotlines year round from 2008 to 2011. A logistic regression model indicated water temperature (T; P probability (Y = −1.75 − 0.06T + 0.10D). Habitat type, surface current velocity, river stage, stage change and non-sturgeon bycatch were not significant predictors (P = 0.26–0.63). Although pallid sturgeon were caught throughout the year, the model predicted that sampling should focus on times when the water temperature is less than 12°C and in deeper water to maximize capture probability; these water temperature conditions commonly occur during November to March in the lower Mississippi River. Further, the significant effect of water temperature which varies widely over time, as well as water depth indicate that any efforts to use the catch rate to infer population trends will require the consideration of temperature and depth in standardized sampling efforts or adjustment of estimates.

  10. The internal architecture of leukocyte lipid body organelles captured by three-dimensional electron microscopy tomography.

    Directory of Open Access Journals (Sweden)

    Rossana C N Melo

    Full Text Available Lipid bodies (LBs, also known as lipid droplets, are complex organelles of all eukaryotic cells linked to a variety of biological functions as well as to the development of human diseases. In cells from the immune system, such as eosinophils, neutrophils and macrophages, LBs are rapidly formed in the cytoplasm in response to inflammatory and infectious diseases and are sites of synthesis of eicosanoid lipid mediators. However, little is known about the structural organization of these organelles. It is unclear whether leukocyte LBs contain a hydrophobic core of neutral lipids as found in lipid droplets from adipocytes and how diverse proteins, including enzymes involved in eicosanoid formation, incorporate into LBs. Here, leukocyte LB ultrastructure was studied in detail by conventional transmission electron microscopy (TEM, immunogold EM and electron tomography. By careful analysis of the two-dimensional ultrastructure of LBs from human blood eosinophils under different conditions, we identified membranous structures within LBs in both resting and activated cells. Cyclooxygenase, a membrane inserted protein that catalyzes the first step in prostaglandin synthesis, was localized throughout the internum of LBs. We used fully automated dual-axis electron tomography to study the three-dimensional architecture of LBs in high resolution. By tracking 4 nm-thick serial digital sections we found that leukocyte LBs enclose an intricate system of membranes within their "cores". After computational reconstruction, we showed that these membranes are organized as a network of tubules which resemble the endoplasmic reticulum (ER. Our findings explain how membrane-bound proteins interact and are spatially arranged within LB "cores" and support a model for LB formation by incorporating cytoplasmic membranes of the ER, instead of the conventional view that LBs emerge from the ER leaflets. This is important to understand the functional capabilities of leukocyte

  11. The internal architecture of leukocyte lipid body organelles captured by three-dimensional electron microscopy tomography.

    Science.gov (United States)

    Melo, Rossana C N; Paganoti, Guillherme F; Dvorak, Ann M; Weller, Peter F

    2013-01-01

    Lipid bodies (LBs), also known as lipid droplets, are complex organelles of all eukaryotic cells linked to a variety of biological functions as well as to the development of human diseases. In cells from the immune system, such as eosinophils, neutrophils and macrophages, LBs are rapidly formed in the cytoplasm in response to inflammatory and infectious diseases and are sites of synthesis of eicosanoid lipid mediators. However, little is known about the structural organization of these organelles. It is unclear whether leukocyte LBs contain a hydrophobic core of neutral lipids as found in lipid droplets from adipocytes and how diverse proteins, including enzymes involved in eicosanoid formation, incorporate into LBs. Here, leukocyte LB ultrastructure was studied in detail by conventional transmission electron microscopy (TEM), immunogold EM and electron tomography. By careful analysis of the two-dimensional ultrastructure of LBs from human blood eosinophils under different conditions, we identified membranous structures within LBs in both resting and activated cells. Cyclooxygenase, a membrane inserted protein that catalyzes the first step in prostaglandin synthesis, was localized throughout the internum of LBs. We used fully automated dual-axis electron tomography to study the three-dimensional architecture of LBs in high resolution. By tracking 4 nm-thick serial digital sections we found that leukocyte LBs enclose an intricate system of membranes within their "cores". After computational reconstruction, we showed that these membranes are organized as a network of tubules which resemble the endoplasmic reticulum (ER). Our findings explain how membrane-bound proteins interact and are spatially arranged within LB "cores" and support a model for LB formation by incorporating cytoplasmic membranes of the ER, instead of the conventional view that LBs emerge from the ER leaflets. This is important to understand the functional capabilities of leukocyte LBs in health and

  12. Kuang's Semi-Classical Formalism for Calculating Electron Capture Cross Sections: A Space- Physics Application

    Science.gov (United States)

    Barghouty, A. F.

    2014-01-01

    Accurate estimates of electroncapture cross sections at energies relevant to the modeling of the transport, acceleration, and interaction of energetic neutral atoms (ENA) in space (approximately few MeV per nucleon) and especially for multi-electron ions must rely on detailed, but computationally expensive, quantum-mechanical description of the collision process. Kuang's semi-classical approach is an elegant and efficient way to arrive at these estimates. Motivated by ENA modeling efforts for apace applications, we shall briefly present this approach along with sample applications and report on current progress.

  13. Absolute activity measurement of the electron-capture-based radionuclides Ce-139, I-125, Ir-192 and Zn-65 by liquid scintillation coincidence counting

    CSIR Research Space (South Africa)

    Van Wyngaardt, WM

    2006-10-01

    Full Text Available measurements formed part of a regional comparison organized by the Asia Pacific Metrology Programme (APMP). Since Ce-139 decays simply by electron-capture to the 166 keV excited state of 139La. This state de-excites through the emission of conversion electrons...

  14. Direct observation of pure one-electron capture from the target inner shell in low-energy p+Na collisions

    NARCIS (Netherlands)

    Knoop, S; Morgenstern, R; Hoekstra, R

    2004-01-01

    One-electron removal in the p+Na collision system has been investigated at low energy (4-25 keV) by means of recoil ion momentum spectroscopy. The focus will be on the contribution of one-electron capture from the Na 2p inner shell into the hydrogen ground state, thereby leaving the Na+ target ion

  15. Estimation of peacock bass (Cichla spp.) mortality rate during catch-release fishing employing different post-capture procedures.

    Science.gov (United States)

    Barroco, L S A; Freitas, C E C; Lima, Á C

    2017-08-17

    The effect of catch-and-release fishing on the survival of peacock bass (Cichla spp.) was evaluated by comparing two types of artificial bait (jig and shallow-diver plugs) and two types of post-catch confinement. Two experiments were conducted during the periods January-February and October-November 2012 in the Unini River, a right-bank tributary of the Negro River. In total, 191 peacock bass were captured. Both groups of fish were subjected to experimental confinement (collective and individual) for three days. Additionally, 11 fish were tagged with radio transmitters for telemetry monitoring. Mortality rate was estimated as the percentage of dead individuals for each type of bait and confinement. For peacock bass caught with jig baits, mortality was zero. The corresponding figure for shallow-diver bait was 1.66% for fish in collective containment, 18.18% for fish monitored by telemetry and 0% for individuals confined individually. Our results show low post-release mortality rates for peacock bass. Furthermore, neither the type of confinement nor the type of bait had a statistically significant influence on mortality rates. While future studies could include other factors in the analysis, our results show that catch-and-release fishing results in low mortality rates.

  16. CO 2 Capture Rate Sensitivity Versus Purchase of CO 2 Quotas. Optimizing Investment Choice for Electricity Sector

    OpenAIRE

    Coussy Paula; Raynal Ludovic

    2014-01-01

    International audience; Carbon capture technology (and associated storage), applied to power plants, reduces atmospheric CO2 emissions. This article demonstrates that, in the particular case of the deployment phase of CO2 capture technology during which CO2 quota price may be low, capturing less than 90% of total CO2 emissions from power plants can be economically attractive. Indeed, for an electric power company capture technology is interesting, only if the discounted marginal cost of captu...

  17. Fragmentation dynamics of CO(2)(3+) investigated by multiple electron capture in collisions with slow highly charged ions.

    Science.gov (United States)

    Neumann, N; Hant, D; Schmidt, L Ph H; Titze, J; Jahnke, T; Czasch, A; Schöffler, M S; Kreidi, K; Jagutzki, O; Schmidt-Böcking, H; Dörner, R

    2010-03-12

    Fragmentation of highly charged molecular ions or clusters consisting of more than two atoms can proceed in a one step synchronous manner where all bonds break simultaneously or sequentially by emitting one ion after the other. We separated these decay channels for the fragmentation of CO(2)(3+) ions by measuring the momenta of the ionic fragments. We show that the total energy deposited in the molecular ion is a control parameter which switches between three distinct fragmentation pathways: the sequential fragmentation in which the emission of an O(+) ion leaves a rotating CO(2+) ion behind that fragments after a time delay, the Coulomb explosion and an in-between fragmentation--the asynchronous dissociation. These mechanisms are directly distinguishable in Dalitz plots and Newton diagrams of the fragment momenta. The CO(2)(3+) ions are produced by multiple electron capture in collisions with 3.2 keV/u Ar(8+) ions.

  18. Half-life of the electron-capture decay of 97Ru: Precision measurement shows no temperature dependence

    CERN Document Server

    Goodwin, J R; Iacob, V E; Hardy, J C; 10.1103/PhysRevC.80.045501

    2009-01-01

    We have measured the half-life of the electron-capture (ec) decay of 97Ru in a metallic environment, both at low temperature (19K), and also at room temperature. We find the half-lives at both temperatures to be the same within 0.1%. This demonstrates that a recent claim that the ec decay half-life for 7Be changes by $0.9% +/- 0.2% under similar circumstances certainly cannot be generalized to other ec decays. Our results for the half-life of 97Ru, 2.8370(14)d at room temperature and 2.8382(14)d at 19K, are consistent with, but much more precise than, previous room-temperature measurements. In addition, we have also measured the half-lives of the beta-emitters 103Ru and 105Rh at both temperatures, and found them also to be unchanged.

  19. Analytical Method Validation of Selected Organochlorine Pesticides in Fortified Rice Using Gas Chromatography with Electron Capture Detector

    Directory of Open Access Journals (Sweden)

    Mutia Kusuma Wardani

    2014-01-01

    Full Text Available Gas chromatography with electron capture detector (GC-ECD has been validated for simultaneous determination of selected organochlorine pesticides namely heptachlor, endosulfan, dieldrin, dan p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT using aldrin as standard internal. Some parameters for analytical method validation were evaluated, i.e. linearity, precision, sensitivity expressed with limit of detection and limit of quantification, and recovery. GC-ECD was linear for determination of these pesticides with r values ≥ 0.99. The values of LOD obtained were 2.50, 2.97, 1.61, and 2.54 ng/mL for heptachlor, endosulphan, dieldrin, and p,p’-DDT, respectively. Furthermore, the relative standard deviation (RSD values obtained for the assessment of analytical precision were lower than those required by Horwitz. Finally, the used GC-ECD method was accurate for determination of these organochlorine psticides in fortified rice samples which were indicated by the acceptable recovery percentages.

  20. Towards saturation of the electron-capture delayed fission probability: The new isotopes 240Es and 236Bk

    Directory of Open Access Journals (Sweden)

    J. Konki

    2017-01-01

    Full Text Available The new neutron-deficient nuclei 240Es and 236Bk were synthesised at the gas-filled recoil separator RITU. They were identified by their radioactive decay chains starting from 240Es produced in the fusion–evaporation reaction 209Bi(34S,3n240Es. Half-lives of 6(2s and 22−6+13s were obtained for 240Es and 236Bk, respectively. Two groups of α particles with energies Eα=8.19(3MeV and 8.09(3MeV were unambiguously assigned to 240Es. Electron-capture delayed fission branches with probabilities of 0.16(6 and 0.04(2 were measured for 240Es and 236Bk, respectively. These new data show a continuation of the exponential increase of ECDF probabilities in more neutron-deficient isotopes.

  1. After-Effects of the Cobalt-57-Iron-57 Electron-Capture Reaction in Hexacyanocobaltate (III) Complexes

    DEFF Research Database (Denmark)

    Fenger, Jørgen Folkvard; Siekierska, K.E.; Olsen, J.

    1973-01-01

    Isomorphous hexacyanocobaltate(III) complexes with the bivalent metal cations Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ have been labelled with 57Co and used as Mössbauer sources. Whilst the spectrum of the complex Fe3[57Co(CN)6]2 can be resolved into a single line corresponding to the ion Fe II...... (CN)6 4– and a doublet, those of all the other sources result in two doublets, of which one corresponds to the ion Fe III (CN)6 3–. The extra doublet in these spectra shows that the 57Co–57Fe electron-capture reaction gives rise to the formation of a new 57Fe labelled species, tentatively identified...

  2. Improving transmission rates of electronic discharge summaries to GPs.

    Science.gov (United States)

    Barr, Rory; Chin, Kuen Yeow; Yeong, Keefai

    2013-01-01

    Discharge summaries are a vital tool to communicate information from Hospital to Primary Care teams; updating GPs about what happened during an admission, and handing over care detailing any follow up care required. Historically, Discharge Summaries have been posted to hospitals, increasing costs for hospitals, creating administrative work for GP practices receiving the letters, and resulting in some letters being lost or delayed in reaching the GP, with implications for patient safety if follow up requests are not received and acted upon. In an effort to improve patient care, the Clinical Commissioning Group in Surrey drew up a contract with Ashford and St Peter's Foundation Trust, aiming to increase the percentage of discharge summaries sent electronically from the rate of 9% sent within 24 hours, to over 75%. This contract set targets of 50% in May, 65% in June, and 80% in July. Financial penalties would be imposed if targets were not achieved, starting in June 2013. The Trust set up a working group comprising of doctors, IT personnel and ward PAs to devise a multi-pronged solution to achieve this target. The electronic discharge summary system was reviewed and improvements were designed and developed to make the process of signing off letters easier, and transmission of signed off letters became automated rather than requiring manual transmission by ward PAs. Presentations and leaflets to explain the importance of prompt completion and transmission of discharge summaries were given to Doctors to improve compliance using the revised IT system. Figures on transmission rates were automatically emailed to key stakeholders every day (Ward PAs, Divisional Leads) showing performance on each ward. This helped identify areas requiring more intervention. Areas (e.g. Day Surgery) that had not used electronic discharge summaries were engaged with, and persuaded to take part. As a result, transmission rates of Discharge Summaries within 24 hours of patient discharge

  3. Electron capture and transfer-ionization processes in {sup 4}He{sup 2+}+Ar collision at 12.5 keV amu{sup -1}

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.; Benhenni, M. [Laboratoire Collisions, Agregats, Reactivite, IRSAMC, UMR 5589 CNRS and Universite Paul Sabatier, 31062 Toulouse Cedex (France)

    1998-05-14

    Electron emission in the {sup 4}He{sup 2+}+Ar collisional system has been investigated at 35 deg. and 12.5 keV amu{sup -1} collision velocity, in coincidence with the recoil target ion charges. Direct single ionization is found to be negligible with respect to single-electron capture. Contributions of transfer-ionization processes are stressed in the production of Ar{sup 2+} to Ar{sup 4+} ions; those of direct ionization, double excitation of the target and double capture into autoionization states of helium are instead found to be much less probable. Among the two-electron processes which explain the formation of Ar{sup 2+} ions, the double capture into autoionizing states of helium remains unimportant with respect to a pure transfer ionization process (one captured electron plus one ionized electron). The measured predominant production of Ar{sup 3+} ions illustrates the role played by three-electron processes, mainly a two-electron transfer accompanied by a single-target ionization. Finally, the formation of Ar{sup 4+} ions is connected with more complex transfer ionization processes. A qualitative analysis of these results is made within the quasimolecular approach. (author). Letter-to-the-editor.

  4. Calculation of Generation Rate of Electron Ion Pairs Ionized by Radioactive Nuclide in Air

    Institute of Scientific and Technical Information of China (English)

    WU; Xiu-feng; ZHANG; Li-feng; LUO; Zhi-fu

    2015-01-01

    Alpha and beta nuclides are widely employed in industrial production and life for the ability of ionization.Static eliminator,ionization smoke detector,electron capture detector and radioactive lightning rod are some typical examples.Alpha/beta rays produce electrons by ionizing the air,and then the charge is transferred during

  5. Molecular treatment of single (dissociative and nondissociative) and double electron capture in He{sup 2+} + H{sub 2} collisions

    Energy Technology Data Exchange (ETDEWEB)

    Errea, L F [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain); Macias, A [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain); Mendez, L [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain); Pons, B [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain); Riera, A [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain)

    2003-04-14

    We present close-coupling calculations of total cross sections for single and double electron capture in He{sup 2+} + H{sub 2} collisions in the range 0.5- 25 keV amu{sup -1}, and compare them with experimental data. We confirm the experimental finding that the dominant process for E {approx}> 3 keV amu{sup -1} is the nondissociative capture He{sup 2+} + H{sub 2} {yields} He{sup +}(2l) + H{sub 2}{sup +} (1{sigma} {sub g}), while at lower energies it is dissociative capture leading to He{sup +}(1s) + H{sup +} + H. Our calculations also show that He(1s2l) is the main output of the two electron capture process. (letter to the editor)

  6. S2O - A software tool for integrating research data from general purpose statistic software into electronic data capture systems.

    Science.gov (United States)

    Bruland, Philipp; Dugas, Martin

    2017-01-07

    Data capture for clinical registries or pilot studies is often performed in spreadsheet-based applications like Microsoft Excel or IBM SPSS. Usually, data is transferred into statistic software, such as SAS, R or IBM SPSS Statistics, for analyses afterwards. Spreadsheet-based solutions suffer from several drawbacks: It is generally not possible to ensure a sufficient right and role management; it is not traced who has changed data when and why. Therefore, such systems are not able to comply with regulatory requirements for electronic data capture in clinical trials. In contrast, Electronic Data Capture (EDC) software enables a reliable, secure and auditable collection of data. In this regard, most EDC vendors support the CDISC ODM standard to define, communicate and archive clinical trial meta- and patient data. Advantages of EDC systems are support for multi-user and multicenter clinical trials as well as auditable data. Migration from spreadsheet based data collection to EDC systems is labor-intensive and time-consuming at present. Hence, the objectives of this research work are to develop a mapping model and implement a converter between the IBM SPSS and CDISC ODM standard and to evaluate this approach regarding syntactic and semantic correctness. A mapping model between IBM SPSS and CDISC ODM data structures was developed. SPSS variables and patient values can be mapped and converted into ODM. Statistical and display attributes from SPSS are not corresponding to any ODM elements; study related ODM elements are not available in SPSS. The S2O converting tool was implemented as command-line-tool using the SPSS internal Java plugin. Syntactic and semantic correctness was validated with different ODM tools and reverse transformation from ODM into SPSS format. Clinical data values were also successfully transformed into the ODM structure. Transformation between the spreadsheet format IBM SPSS and the ODM standard for definition and exchange of trial data is feasible

  7. Capturing district nursing through a knowledge-based electronic caseload analysis tool (eCAT).

    Science.gov (United States)

    Kane, Kay

    2014-03-01

    The Electronic Caseload Analysis Tool (eCAT) is a knowledge-based software tool to assist the caseload analysis process. The tool provides a wide range of graphical reports, along with an integrated clinical advisor, to assist district nurses, team leaders, operational and strategic managers with caseload analysis by describing, comparing and benchmarking district nursing practice in the context of population need, staff resources, and service structure. District nurses and clinical lead nurses in Northern Ireland developed the tool, along with academic colleagues from the University of Ulster, working in partnership with a leading software company. The aim was to use the eCAT tool to identify the nursing need of local populations, along with the variances in district nursing practice, and match the workforce accordingly. This article reviews the literature, describes the eCAT solution and discusses the impact of eCAT on nursing practice, staff allocation, service delivery and workforce planning, using fictitious exemplars and a post-implementation evaluation from the trusts.

  8. Correlation between metabolic reduction rates and electron affinity of nitroheterocycles

    Energy Technology Data Exchange (ETDEWEB)

    Olive, P.L.

    1979-11-01

    Nitroheterocyclic compounds can selectively sensitize hypoxic (tumor) cells to radiation damage in vitro. However, results in vivo have generally been less optimistic, inasmuch as metabolic reduction of these drugs not only limits effective lifetime but also produces metabolic intermediates with marked cytotoxic and carcinogenic activity. With three reducing systems in vitro, E. coli B/r, mouse L-929 cells, and mouse liver microsomes, the rate of nitroreduction of several nitroheterocycles was found to be proportional to their electron affinity. Since nitroreduction has previously been correlated with subsequent cytotoxicity, DNA damage, and mutagenicity, the present results suggest that improvements in the therapeutic efficacy of nitroheterocycles (i.e., sensitization without toxicity and carcinogenicity) will be dependent on development of drugs with more appropriate pharmacological properties.

  9. Longitudinal T1 relaxation rate (R1) captures changes in short-term Mn exposure in welders.

    Science.gov (United States)

    Lewis, Mechelle M; Flynn, Michael R; Lee, Eun-Young; Van Buren, Scott; Van Buren, Eric; Du, Guangwei; Fry, Rebecca C; Herring, Amy H; Kong, Lan; Mailman, Richard B; Huang, Xuemei

    2016-12-01

    We demonstrated recently that the T1 relaxation rate (R1) captured short-term Mn exposure in welders with chronic, relatively low exposure levels in a cross-sectional study. In the current study, we used a longitudinal design to examine whether R1 values reflect the short-term dynamics of Mn exposure. Twenty-nine welders were evaluated at baseline and 12 months. Occupational questionnaires estimated short-term welding exposure using welding hours in the 90days prior to each study visit (HrsW90). In addition, blood Mn levels, the pallidal index (PI; globus pallidus T1-weighted intensity (T1WI)/frontal white matter T1WI), and R1 values in brain regions of interest (ROIs) were determined as Mn biomarkers at each visit. Associations between changes in estimated welding exposure and changes in purported Mn biomarkers were assessed by Spearman's correlations with adjustment for age and baseline R1, HrsW90, and blood Mn values. Changes in welding hours (HrsW90: the short-term welding exposure estimate), was associated significantly with changes in R1 values in the putamen (r=0.541, p=0.005), caudate (R=0.453, p=0.023), globus pallidus (R=0.430, p=0.032), amygdala (R=0.461, p=0.020), and hippocampus (R=0.447, p=0.025), but not with changes in blood Mn levels or the PI. Changes in R1 values correlated with changes in the short-term welding exposure estimate, but not with more traditional measures of Mn exposure (blood Mn levels or PI). These results suggest that R1 may serve as a useful marker to capture the short-term dynamics in Mn brain accumulation related to welding exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Optimization of metallic magnetic calorimeters for high resolution measurement of the {sup 163}Ho electron capture spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Haehnle, Sebastian [Kirchhoff-Institute for Physics, Heidelberg University (Germany); Collaboration: ECHo-Collaboration

    2015-07-01

    The absolute scale of the neutrino mass eigenstates is one of the puzzles in modern particle physics. One method to investigate the value of the electron neutrino mass is to analyse the high energy region of the {sup 163}Ho electron capture spectrum. In the ECHo experiment low temperature metallic magnetic calorimeters (MMCs) are used for the calorimetric measurements of the EC spectrum of {sup 163}Ho. To ensure 100% quantum efficiency, the {sup 163}Ho ions are implanted into the gold absorber. Experiments carried out with a first detector prototype have demonstrated that MMC-based detectors fulfill the requirements in terms of energy resolution, rise-time and energy calibration. We discuss methods to further optimize the performance of MMCs with implanted {sup 163}Ho. Our aim is to achieve an energy resolution Δ E{sub FWHM} < 5 eV and a signal rise-time τ < 100 ns. An important aspect of this optimization is to define the maximum activity per pixel. This will result from a compromise between allowed unresolved pile-up fraction, additional heat capacity in the absorber due to Ho ions in the absorber material and minimization of the pixel number. We discuss experimental approaches for the determination of the optimal activity per pixel.

  11. Single electron ionization and electron capture cross sections for (C{sup 6+}, H{sub 2}O) interaction within the Classical Trajectory Monte Carlo (CTMC) approach

    Energy Technology Data Exchange (ETDEWEB)

    Tran, H.N., E-mail: tranngochoang@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Dao, D.D. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Incerti, S. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Université de Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); Bernal, M.A. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, SP (Brazil); Karamitros, M. [CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Université de Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); Nhan Hao, T.V. [Center of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam); Center for Theoretical and Computational Physics, College of Education, Hue University, 34 Le Loi Street, Hue City (Viet Nam); Dang, T.M. [VNUHCM-University of Science (Viet Nam); Francis, Z. [Saint Joseph University, Beyrouth (Lebanon)

    2016-01-01

    In this work, we present a derivation of cross sections for single ionization and electron capture processes within the Classical Trajectory Monte Carlo (CTMC) approach. Specifically, we have used a potential stemming from an ab initio calculation in Green et al.’s framework to describe the dynamics of the water molecule system. Proposing a modified version of the Classical Over-Barrier (COB) potential, we have found that a cut-off of roughly 28 a.u. on the initial distance of the projectile produced a reasonable accuracy. A global agreement has been obtained in our calculations compared to experimental and other theoretical results for C{sup 6+} ion energies ranging from 10 keV/u to 10 MeV/u.

  12. Detection of perfluorinated taggants in electric blasting caps by electron capture monitors

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, R N; Goodrich, R W; Cote, E A

    1978-01-01

    Three types of monitors or detecting instruments for determining the presence of perfluorinated taggants have been developed and validated in field studies. Each of the three versions--a portable continuous real-time monitor, a portable concentrating chromatograph, and a fixed station high sensitivity chromatograph -- have been utilized for detecting these types of compounds in atmospheric tracer studies. The portable continuous monitor, which has a detection capability of two parts of taggant in one trillion parts of air (2 pp 10/sup 12/), has been used in three field tracer studies in the past 18 months, operating on-board aircraft. In a scenario such as continuous on-line screening of checked and hand-carried luggage at airport environments, the sensitivity and response time are more than adequate. Confirmation of the method applied to conveyor belt suitcase screening has been demonstrated. A small concentrating field instrument was developed and field tested more than a year ago. Five minute repetitive sampling rates are estimated to ultimately provide limits of detection for the taggant compounds at about 5 pp 10/sup 16/ and could be extended as much as another 50-fold lower. Applications potentially include detecting vapor tagged explosives in meeting rooms, corridors and passageways, and on-board aircraft.

  13. Kuang's Semi-Classical Formalism for Electron Capture Cross-Sections in Ion-Ion Collisions at Approximately to MeV/amu: Application to ENA Modeling

    Science.gov (United States)

    Barghouty, A. F.

    2012-01-01

    Recent discovery by STEREO A/B of energetic neutral hydrogen is spurring an interest and need for reliable estimates of electron capture cross sections at few MeVs per nucleon as well as for multi-electron ions. Required accuracy in such estimates necessitates detailed and involved quantum-mechanical calculations or expensive numerical simulations. For ENA modeling and similar purposes, a semi-classical approach offers a middle-ground approach. Kuang's semiclassical formalism to calculate electron-capture cross sections for single and multi-electron ions is an elegant and efficient method, but has so far been applied to limited and specific laboratory measurements and at somewhat lower energies. Our goals are to test and extend Kuang s method to all ion-atom and ion-ion collisions relevant to ENA modeling, including multi-electron ions and for K-shell to K-shell transitions.

  14. Discriminating the drivers of edge effects on nest predation: forest edges reduce capture rates of ship rats (Rattus rattus, a globally invasive nest predator, by altering vegetation structure.

    Directory of Open Access Journals (Sweden)

    Jay Ruffell

    Full Text Available Forest edges can strongly affect avian nest success by altering nest predation rates, but this relationship is inconsistent and context dependent. There is a need for researchers to improve the predictability of edge effects on nest predation rates by examining the mechanisms driving their occurrence and variability. In this study, we examined how the capture rates of ship rats, an invasive nest predator responsible for avian declines globally, varied with distance from the forest edge within forest fragments in a pastoral landscape in New Zealand. We hypothesised that forest edges would affect capture rates by altering vegetation structure within fragments, and that the strength of edge effects would depend on whether fragments were grazed by livestock. We measured vegetation structure and rat capture rates at 488 locations ranging from 0-212 m from the forest edge in 15 forest fragments, seven of which were grazed. Contrary to the vast majority of previous studies of edge effects on nest predation, ship rat capture rates increased with increasing distance from the forest edge. For grazed fragments, capture rates were estimated to be 78% lower at the forest edge than 118 m into the forest interior (the farthest distance for grazed fragments. This relationship was similar for ungrazed fragments, with capture rates estimated to be 51% lower at the forest edge than 118 m into the forest interior. A subsequent path analysis suggested that these 'reverse' edge effects were largely or entirely mediated by changes in vegetation structure, implying that edge effects on ship rats can be predicted from the response of vegetation structure to forest edges. We suggest the occurrence, strength, and direction of edge effects on nest predation rates may depend on edge-driven changes in local habitat when the dominant predator is primarily restricted to forest patches.

  15. Discriminating the drivers of edge effects on nest predation: forest edges reduce capture rates of ship rats (Rattus rattus), a globally invasive nest predator, by altering vegetation structure.

    Science.gov (United States)

    Ruffell, Jay; Didham, Raphael K; Barrett, Paul; Gorman, Nic; Pike, Rhonda; Hickey-Elliott, Andrée; Sievwright, Karin; Armstrong, Doug P

    2014-01-01

    Forest edges can strongly affect avian nest success by altering nest predation rates, but this relationship is inconsistent and context dependent. There is a need for researchers to improve the predictability of edge effects on nest predation rates by examining the mechanisms driving their occurrence and variability. In this study, we examined how the capture rates of ship rats, an invasive nest predator responsible for avian declines globally, varied with distance from the forest edge within forest fragments in a pastoral landscape in New Zealand. We hypothesised that forest edges would affect capture rates by altering vegetation structure within fragments, and that the strength of edge effects would depend on whether fragments were grazed by livestock. We measured vegetation structure and rat capture rates at 488 locations ranging from 0-212 m from the forest edge in 15 forest fragments, seven of which were grazed. Contrary to the vast majority of previous studies of edge effects on nest predation, ship rat capture rates increased with increasing distance from the forest edge. For grazed fragments, capture rates were estimated to be 78% lower at the forest edge than 118 m into the forest interior (the farthest distance for grazed fragments). This relationship was similar for ungrazed fragments, with capture rates estimated to be 51% lower at the forest edge than 118 m into the forest interior. A subsequent path analysis suggested that these 'reverse' edge effects were largely or entirely mediated by changes in vegetation structure, implying that edge effects on ship rats can be predicted from the response of vegetation structure to forest edges. We suggest the occurrence, strength, and direction of edge effects on nest predation rates may depend on edge-driven changes in local habitat when the dominant predator is primarily restricted to forest patches.

  16. Theoretical state-selective and total cross sections for electron capture from helium atoms by fully stripped ions

    Science.gov (United States)

    Mančev, I.; Milojević, N.; Belkić, Dž.

    2015-03-01

    The four-body boundary-corrected first Born (CB1-4B) approximation is used to compute cross sections for single electron capture from helium targets by fully stripped ions. The projectile ions are H+, He2+, Li3+, Be4+, B5+, C6+, N7+, O8+, and F9+. An extensive list of theoretical state-to-state cross sections in these collisions at energies ranging from 20 to 10 000 keV/amu is given. This list includes the state-selective cross sections Qnlm for each individual triple of the usual quantum numbers { n , l , m } of the final hydrogen-like states alongside Qnl and Qn for the pertinent sub-shells and shells where the respective summations over m and { l , m } have been carried out. The maximal value of the principal quantum number n was chosen to vary from 4 (H+) to 10 (F9+) so as to satisfy the condition n ≥ZP, where ZP is the nuclear charge of the projectile. Usually, the largest cross sections stem from those values of n that match the projectile charge (n =ZP) . The total cross sections for capture summed over all the quantum numbers { n , l , m } are also tabulated. The overall goal of this study is to fill in lacunae in the existing databases of charge exchange cross sections that are needed in several inter-disciplinary fields. For example, in particle transport physics, which is of utmost importance in such emerging branches as hadron therapy, these cross sections constitute a part of the multifaceted input data for stochastic simulations of energy losses of multiply charged ions in matter, including tissue. Other significant uses of the present data are anticipated in charge exchange diagnostics within thermonuclear research project as well as in applications covering the relevant parts of plasma physics and astrophysics.

  17. Multiple ionization of neon induced by Li3+ and C3+ projectiles: influence of projectile screening in the ionization and electron capture channels

    Science.gov (United States)

    Ihani, J. S.; Luna, H.; Wolff, W.; Montenegro, E. C.

    2013-06-01

    Neq + (q = 1,2,3,4) ionization and charge exchange cross sections (total electron capture, single electron capture and transfer ionization) in the collisions with Li3+, with energies between 100 and 900 keV amu-1, and C3+, with energies between 250 and 500 keV amu-1 are reported. Bare Li3+ projectiles give a key benchmark to study the role of projectile screening in collisions involving dressed projectile ions, and the measurements have shown a strong screening effect for all n-fold recoil ion charge states in the ionization channel which, unexpectedly, does not appear for transfer ionization.

  18. A data-capture system for post-marketing surveillance of drugs that integrates with hospital electronic health records

    Directory of Open Access Journals (Sweden)

    Yamamoto K

    2011-04-01

    Full Text Available Keiichi Yamamoto1, Shigemi Matsumoto2, Kazuhiro Yanagihara2, Satoshi Teramukai1, Masanori Fukushima1,2,31Department of Clinical Trial Design and Management, Translational Research Center, Kyoto University Hospital, Kyoto, Japan; 2Outpatient Oncology Unit, Kyoto University Hospital, Kyoto, Japan; 3Translational Research Informatics Center, Foundation for Biomedical Research and Innovation, Kobe, JapanPurpose: In conventional clinical studies, the cost of data management for the purposes of quality control tend to be high and collecting paper-based case report forms (CRFs can be burdensome, because paper-based CRFs must be developed and filled out for each clinical study protocol. Use of electronic health records (EHRs for this purpose could reduce costs and improve data quality in clinical studies. Kyoto University Hospital launched an EHR system in January 2005. At the same time, a replicate of that database was established for other purposes. At the Outpatient Oncology Unit of Kyoto University Hospital we developed a data-capture system that includes a cancer clinical database system and a data warehouse for outcomes studies. This system allows us to accumulate data at low cost and apply it to various uses in clinical or outcomes studies. Here we report on the application of this system to the post-marketing surveillance of drugs.Methods: We evaluated the availability of this system and identified problems for future development. With this system investigators can register cases for post-marketing surveillance, and the registered cases are listed on a screen. When CRFs for a particular case are required, data can be extracted from the list and CRFs are produced in PDF format.Results and conclusion: In this study we confirmed the applicability of our new system to post-marketing surveillance in providing prompt and efficient data exchange. We expect it to reduce the cost of data management and analysis and to improve the quality of data in post

  19. Wobbly strings: calculating the capture rate of a webcam using the rolling shutter effect in a guitar

    Science.gov (United States)

    Cunnah, David

    2014-07-01

    In this paper I propose a method of calculating the time between line captures in a standard complementary metal-oxide-semiconductor (CMOS) webcam using the rolling shutter effect when filming a guitar. The exercise links the concepts of wavelength and frequency, while outlining the basic operation of a CMOS camera through vertical line capture.

  20. Valence parity to distinguish c' and z• ions from electron capture dissociation/electron transfer dissociation of peptides: effects of isomers, isobars, and proteolysis specificity.

    Science.gov (United States)

    Mao, Yuan; Tipton, Jeremiah D; Blakney, Greg T; Hendrickson, Christopher L; Marshall, Alan G

    2011-10-15

    Valence parity provides a way to distinguish between N-terminal and C-terminal electron capture dissociation/electron transfer dissociation (ECD/ETD) product ions based on their number of hydrogen plus nitrogen atoms determined by accurate mass measurement and forms a basis for de novo peptide sequencing. The effect of mass accuracy (0.1-1 ppm error) on c'/z(•) overlap and unique elemental composition overlap is evaluated for a database of c'/z(•) product ions each based on all possible amino acid combinations and four subset databases containing the same c' ions but with z(•) ions determined by in silico digestion with trypsin, Glu-C, Lys-C, or chymotrypsin. High mass accuracy reduces both c'/z(•) overlap and unique elemental composition overlap. Of the four proteases, trypsin offers slightly better discrimination between N- and C-terminal ECD/ETD peptides. Interestingly, unique elemental composition overlap curves for c'/c' and z(•)/z(•) peptide ions exhibit discontinuities at certain nominal masses for 0.1-1.0 ppm mass error. Also, as noted in the companion article (Polfer et al. Anal. Chem.2011, DOI: 10.1021/ac201624t), the number of ECD/ETD product ion amino acid compositions as a function of nominal mass increases exponentially with mass but with a superimposed modulation due to higher prevalence of certain elemental compositions.

  1. Multicentre clinical trials' data management: a hybrid solution to exploit the strengths of electronic data capture and electronic health records systems.

    Science.gov (United States)

    Fraccaro, Paolo; Dentone, Chiara; Fenoglio, Daniela; Giacomini, Mauro

    2013-12-01

    Clinical Trials (CTs) are indispensable instruments for evidence-based medicine and frequently necessitate the management, sharing and analysis of large amounts of data amongst partners in different locations. To effectively satisfy these requirements, the proposed solution combines a web platform and a Clinical Data Management System (CDMS) to exploit the strengths of Electronic Health Records (EHR) and Electronic Data Capture (EDC) systems. The core of the proposal is a relational database which has high data structuring characteristics and utilises biomedical controlled vocabularies (e.g. LOINC and ICD). In addition, units and normality ranges were collected for data comparison through the application of the Z-score transformation. The obtained CDMS preserves the EDC's flexibility and user autonomy and permits the creation of patient cohorts, as in the EHR. Accordingly, clinical information, after the initial recording, is available for different simultaneous multicentre CTs. Furthermore, interface runtime controls guarantee high data quality during data entering processes. Currently, the proposed system has been developed in the HIV and eye diseases fields in Italy. The proposed solution is flexible and suitable to perform multicentre research within a varying range of medical domains. In the future, the automatic importation of information from hospitals has been planned through an HL7 standard interface which would improve both data quantity and quality.

  2. Improving Interprofessional Consistency in Electronic Fetal Heart Rate Interpretation.

    Science.gov (United States)

    Govindappagari, Shravya; Zaghi, Sahar; Zannat, Ferdous; Reimers, Laura; Goffman, Dena; Kassel, Irene; Bernstein, Peter S

    2016-07-01

    Objective To determine if mandatory online training in electronic fetal monitoring (EFM) improved agreement in documentation between obstetric care providers and nurses on labor and delivery. Methods Health care professionals working in obstetrics at our institution were required to complete a course on EFM interpretation. We performed a retrospective chart review of 701 charts including patients delivered before and after the introduction of the course to evaluate agreement among providers in their documentation of their interpretations of the EFM tracings. Results Agreement between provider and nurse documentation at the time of admission improved for variability and accelerations (variability: 91.1 vs. 98.3%, p < 0.001; and accelerations: 75.2 vs. 87.7%, p < 0.001). Similarly, agreement improved at the time of the last note prior to delivery for documentation of variability and accelerations (variability: 82.1 vs. 90.6%, p = 0.001; and accelerations: 56.7 vs. 68.6%, p = 0.0012). Agreement in interpretation of decelerations both at the time of admission and at the time of delivery increased (86.3 vs. 90.6%, p = 0.0787, and 56.7 vs. 61.1%, p = 0.2314, respectively) but was not significant. Conclusion An online EFM course can significantly improve consistency in multidisciplinary documentation of fetal heart rate tracing interpretation.

  3. Collision rates for rare cell capture in periodic obstacle arrays strongly depend on density of cell suspension.

    Science.gov (United States)

    Cimrák, I

    2016-11-01

    Recently, computational modelling has been successfully used for determination of collision rates for rare cell capture in periodic obstacle arrays. The models were based on particle advection simulations where the cells were advected according to velocity field computed from two dimensional Navier-Stokes equations. This approach may be used under the assumption of very dilute cell suspensions where no mutual cell collisions occur. We use the object-in-fluid framework to demonstrate that even with low cell-to-fluid ratio, the optimal geometry of the obstacle array significantly changes. We show computational simulations for ratios of 3.5, 6.9 and 10.4% determining the optimal geometry of the periodic obstacle arrays. It was already previously demonstrated that cells in periodic obstacle arrays follow trajectories in two modes: the colliding mode and the zig-zag mode. The colliding mode maximizes the cell-obstacle collision frequency. Our simulations reveal that for dilute suspensions and for suspensions with cell-to-fluid ratio 3.5%, there is a range of column shifts for which the cells follow colliding trajectories. However we showed, that for 6.9 and 10.4%, the cells never follow colliding trajectories.

  4. Impact parameter dependent electron capture by decelerated U{sup 91+} ions at 20 MeV/u using crystal channeling conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dauvergne, D. E-mail: d.dauvergne@ipnl.in2p3.fr; Braeuning-Demian, A.; Bosch, F.; Braeuning, H.; Chevallier, M.; Cohen, C.; Gumberidze, A.; L' Hoir, A.; Kirsch, R.; Kozhuharov, C.; Liesen, D.; Mokler, P.H.; Poizat, J.C.; Ray, C.; Stoehlker, Th.; Tarisien, M.; Testa, E.; Toleikis, S.; Toulemonde, M

    2003-05-01

    We present results of an experiment using decelerated U{sup 91+} ions, extracted from the GSI-ESR storage ring, and transmitted through a thin silicon crystal in channeling conditions. Charge state at emergence, secondary electron multiplicity and X-rays are measured simultaneously. These conditions allow to study the competition between mechanical electron capture (MEC) and radiative electron capture (REC) as a function of impact parameter. We observe that REC is the dominant charge exchange process for the best channeled ions, i.e. those travelling always far from the silicon target core electrons. For ions with high transverse energy, MEC into highly excited states is counterbalanced by enhanced ionization arising from a succession of close collisions along atomic rows.

  5. Native electrospray ionization and electron-capture dissociation for comparison of protein structure in solution and the gas phase.

    Science.gov (United States)

    Zhang, Hao; Cui, Weidong; Gross, Michael L

    2013-11-15

    The importance of protein and protein-complex structure motivates improvements in speed and sensitivity of structure determination in the gas phase and comparison with that in solution or solid state. An opportunity for the gas phase measurement is mass spectrometry (MS) combined with native electrospray ionization (ESI), which delivers large proteins and protein complexes in their near-native states to the gas phase. In this communication, we describe the combination of native ESI, electron-capture dissociation (ECD), and top-down MS for exploring the structures of ubiquitin and cytochrome c in the gas phase and their relation to those in the solid-state and solution. We probe structure by comparing the protein's flexible regions, as predicted by the B-factor in X-ray crystallography, with the ECD fragments. The underlying hypothesis is that maintenance of structure gives fragments that can be predicted from B-factors. This strategy may be applicable in general when X-ray structures are available and extendable to the study of intrinsically disordered proteins.

  6. Probing the Gaseous Structure of a β-Hairpin Peptide with H/D Exchange and Electron Capture Dissociation

    Science.gov (United States)

    Straus, Rita N.; Jockusch, Rebecca A.

    2016-12-01

    An improved understanding of the extent to which native protein structure is retained upon transfer to the gas phase promises to enhance biological mass spectrometry, potentially streamlining workflows and providing fundamental insights into hydration effects. Here, we investigate the gaseous conformation of a model β-hairpin peptide using gas-phase hydrogen-deuterium (H/D) exchange with subsequent electron capture dissociation (ECD). Global gas-phase H/D exchange levels, and residue-specific exchange levels derived from ECD data, are compared among the wild type 16-residue peptide GB1p and several variants. High protection from H/D exchange observed for GB1p, but not for a truncated version, is consistent with the retention of secondary structure of GB1p in the gas phase or its refolding into some other compact structure. Four alanine mutants that destabilize the hairpin in solution show levels of protection similar to that of GB1p, suggesting collapse or (re)folding of these peptides upon transfer to the gas phase. These results offer a starting point from which to understand how a key secondary structural element, the β-hairpin, is affected by transfer to the gas phase. This work also demonstrates the utility of a much-needed addition to the tool set that is currently available for the investigation of the gaseous conformation of biomolecules, which can be employed in the future to better characterize gaseous proteins and protein complexes.

  7. Evaluation of Pentachlorophenol Residues in Some Hygienic Papers Prepared from Virgin and Secondary Pulp by Electron Capture Gas Chromatographic Method

    Directory of Open Access Journals (Sweden)

    Behrouz Akbari-adergani

    2016-01-01

    Full Text Available In this study, residual amount of pentachlorophenol (PCP as the most important paper preservative, which is extremely hazardous pollutant, was determined in some tissue papers and napkins. Twenty-five samples of two producing hygienic paper factories prepared from virgin and secondary pulp were analyzed for the presence of trace amount of PCP. The analytical procedure involved direct extraction of PCP from hygienic paper and its determination by gas chromatography with electron capture detection. The statistical results for the analysis of all samples revealed that there were significant differences between mean of PCP in hygienic papers prepared from virgin and secondary pulp (P<0.05. This method gave recoveries of 86-98% for hygienic paper made from virgin pulp and 79-92% for hygienic paper made from secondary pulp. The limit of detection (LOD and limit of quantification (LOQ for PCP were 6.3 and 21.0 mg/kg, respectively. The analytical method has the requisite sensitivity, accuracy, precision and specificity to assay PCP in hygienic papers. This study demonstrates a concern with exposition to PCP considering that hygienic paper is largely consumed in the society.

  8. Probing the Gaseous Structure of a β-Hairpin Peptide with H/D Exchange and Electron Capture Dissociation

    Science.gov (United States)

    Straus, Rita N.; Jockusch, Rebecca A.

    2017-02-01

    An improved understanding of the extent to which native protein structure is retained upon transfer to the gas phase promises to enhance biological mass spectrometry, potentially streamlining workflows and providing fundamental insights into hydration effects. Here, we investigate the gaseous conformation of a model β-hairpin peptide using gas-phase hydrogen-deuterium (H/D) exchange with subsequent electron capture dissociation (ECD). Global gas-phase H/D exchange levels, and residue-specific exchange levels derived from ECD data, are compared among the wild type 16-residue peptide GB1p and several variants. High protection from H/D exchange observed for GB1p, but not for a truncated version, is consistent with the retention of secondary structure of GB1p in the gas phase or its refolding into some other compact structure. Four alanine mutants that destabilize the hairpin in solution show levels of protection similar to that of GB1p, suggesting collapse or (re)folding of these peptides upon transfer to the gas phase. These results offer a starting point from which to understand how a key secondary structural element, the β-hairpin, is affected by transfer to the gas phase. This work also demonstrates the utility of a much-needed addition to the tool set that is currently available for the investigation of the gaseous conformation of biomolecules, which can be employed in the future to better characterize gaseous proteins and protein complexes.

  9. Mapping a Noncovalent Protein-Peptide Interface by Top-Down FTICR Mass Spectrometry Using Electron Capture Dissociation

    Science.gov (United States)

    Clarke, David J.; Murray, Euan; Hupp, Ted; Mackay, C. Logan; Langridge-Smith, Pat R. R.

    2011-08-01

    Noncovalent protein-ligand and protein-protein complexes are readily detected using electrospray ionization mass spectrometry (ESI MS). Furthermore, recent reports have demonstrated that careful use of electron capture dissociation (ECD) fragmentation allows covalent backbone bonds of protein complexes to be dissociated without disruption of noncovalent protein-ligand interactions. In this way the site of protein-ligand interfaces can be identified. To date, protein-ligand complexes, which have proven tractable to this technique, have been mediated by ionic electrostatic interactions, i.e., ion pair interactions or salt bridging. Here we extend this methodology by applying ECD to study a protein-peptide complex that contains no electrostatics interactions. We analyzed the complex between the 21 kDa p53-inhibitor protein anterior gradient-2 and its hexapeptide binding ligand (PTTIYY). ECD fragmentation of the 1:1 complex occurs with retention of protein-peptide binding and analysis of the resulting fragments allows the binding interface to be localized to a C-terminal region between residues 109 and 175. These finding are supported by a solution-phase competition assay, which implicates the region between residues 108 and 122 within AGR2 as the PTTIYY binding interface. Our study expands previous findings by demonstrating that top-down ECD mass spectrometry can be used to determine directly the sites of peptide-protein interfaces. This highlights the growing potential of using ECD and related top-down fragmentation techniques for interrogation of protein-protein interfaces.

  10. Convolution/deconvolution of generalized Gaussian kernels with applications to proton/photon physics and electron capture of charged particles

    CERN Document Server

    Ulmer, W

    2012-01-01

    Scatter processes of photons lead to blurring of images produced by CT (computed tomography) or CBCT (cone beam computed tomography) in the KV domain or portal imaging in the MV domain (KV: kilovolt age, MV: megavoltage). Multiple scatter is described by, at least, one Gaussian kernel. In various situations, this approximation is crude, and we need two/three Gaussian kernels to account for the long-range tails (Landau tails), which appear in the Moli\\`ere scatter of protons, energy straggling and electron capture of charged particles passing through matter and Compton scatter of photons. The ideal image (source function) is subjected to Gaussian convolutions to yield a blurred image recorded by a detector array. The inverse problem is to obtain the ideal source image from measured image. Deconvolution methods of linear combinations of two/three Gaussian kernels with different parameters s0, s1, s2 can be derived via an inhomogeneous Fredholm integral equation of second kind (IFIE2) and Liouville - Neumann ser...

  11. Finite Forward Acceptance Angles for Single Electron Capture by ^3He^2+ Ions in He and H_2

    Science.gov (United States)

    Mawhorter, Rj; Greenwood, J.; Smith; Chutjian, A.

    2004-05-01

    Perhaps surprisingly, electron capture scattering angles of a few degrees or more are observed for slow ions impacting light targets. Gas cells must be designed with this in mind. Indeed the difference between small acceptance angle results(W.L. Nutt, et al., J. Phys. B 8), 1457 (1978) and the larger acceptance-angle studies of both Kusakabe, et al.(T. Kusakabe, et al., J. Phys. Soc. Japan 59), 1218 (1990) and our group at JPL (presented here; energy range 0.33-4.67 keV/amu) for ^3He^2+ in H2 can be ascribed to this effect. Olson and Kimura(R. E. Olson and M. Kimura, J. Phys. B 15), 4231 (1982) have modeled the problem theoretically. We use existing differential cross section data(D. Bordenave-Montesquieu and R. Dagnac, J. Phys. B 27), 543 1994) for both H_2/ D2 and ^4He targets to calculate realistic acceptance angles. The resulting small total cross section corrections provide reliable absolute results for these benchmark systems. This work was carried out at JPL/Caltech, and was supported through agreement with NASA.

  12. Electron trajectories and growth rates of the plasma wave pumped free-electron laser

    Science.gov (United States)

    Jafari, S.; Jafarinia, F.; Nilkar, M.; Amiri, M.

    2014-12-01

    A theory for a plasma wave wiggler has been described which employs the plasma whistler wave for producing laser radiation in a free-electron laser (FEL). While electromagnetically pumped FELs have been proven to be an effective means generating short wavelengths, practical difficulties occur in the design of these wigglers. For this reason, it is found that a plasma wave wiggler can be employed in concept with an electromagnetic wave wiggler due to both higher tunability and holding the focus of pump wave and e-beam over a significant distance to achieve a suitable amplification. Plasma in the presence of static magnetic field supports a plasma whistler wave. The plasma wiggler period can be tuned by varying the plasma density and/or ambient magnetic field. Electron trajectories have been analyzed using single particle dynamics and regimes of orbital stability have been demonstrated. A polynomial dispersion relation for electromagnetic and space-charge waves has then been derived, analytically. Numerical studies of the dispersion relation reveal that the growth rates are sensitive functions of the cyclotron frequency. It has been shown that by increasing the axial magnetic field strength (or cyclotron frequency), the growth rate for groups I and III orbits increases, while a growth decrement has been obtained for groups II and IV orbits.

  13. LINE EMISSION AND ANISOTROPY EFFECTS IN C6+ ELECTRON-CAPTURE FROM LI(2S), LI-ASTERISK(2P) AND H-ASTERISK(N=2)

    NARCIS (Netherlands)

    OLSON, RE; HOEKSTRA, R

    1995-01-01

    Line emission cross sections for visible transitions after electron capture collisions of C6+ With Li(2s), Li-*(2p), and H-*(n = 2) are calculated for energies up to 50 keV/u; the values agree with available Li(2s) data. Anisotropy parameters are also given for aligned Li-*(2p). The results were obt

  14. Q-Dependence of the double capture cross sections measured by electron spectroscopy at 10 qkeV (q = 4-8). Comparison with other experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A.; Boudjema, M.; Benoit-Cattin, P.; Gleizes, A.; Moretto-Capelle, P.

    1989-01-01

    The q dependence of cross sections for double capture into autoionising states has been investigated by electron spectroscopy. It is shown that they are independent of the ionic core. Our results are compared with all other available experimental data obtained at 10 qkeV collision energy.

  15. Simultaneous analysis of polychlorinated biphenyls and organochlorine pesticides in seawater samples by membrane-assisted solvent extraction combined with gas chromatography-electron capture detector and gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Shi, Xizhi; Tang, Zigang; Sun, Aili; Zhou, Lei; Zhao, Jian; Li, Dexiang; Chen, Jiong; Pan, Daodong

    2014-12-01

    A highly efficient and environment-friendly membrane-assisted solvent extraction system combined with gas chromatography-electron capture detector was applied in the simultaneous determination of 17 polychlorinated biphenyls and organochlorine pesticides in seawater samples. Variables affecting extraction efficiency, including extraction solvent used, stirring rate, extraction time, and temperature, were optimized extensively. Under optimal extraction conditions, recoveries between 76.9% and 104.6% in seawater samples were achieved, and relative standard deviation values below 10% were obtained. The limit of detection (signal-to-noise ratio=3) and limit of quantification (signal-to-noise ratio=10) of 17 polychlorinated biphenyls and organochlorine pesticides in seawater ranged from 0.14ngL(-1) to 0.36ngL(-1) and 0.46ngL(-1) to 1.19ngL(-1), respectively. Matrix effects on extraction efficiency were evaluated by comparing with the results obtained using tap water. The extraction effect of developed membrane-assisted solvent extraction method was further demonstrated by gas chromatography-tandem mass spectrometry which can provide structural information of the analytes for more accurate identification, and results identical to those produced by gas chromatography-electron capture detector were obtained. These findings demonstrate the applicability of the developed membrane-assisted solvent extraction determination method for coupling to gas chromatography-electron capture detector or tandem mass spectrometry for determining polychlorinated biphenyls and organochlorine pesticides in seawater samples.

  16. Experimental investigations of electron capture from atomic hydrogen and deuterium by alpha particles. Annual progress report, 15 September 1991--14 September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Gay, T.J.; Park, J.T.

    1992-11-01

    We report progress made during the period 15 September 1991--14 September 1992 on the project ``Experimental Investigations of Electron Capture from Atomic Hydrogen and Deuterium by Alpha Particles``. In the past year we have developed reliable, narrow energy spread, high-current sources of He{sup ++} based on direct-current magentron and electron-cyclotron resonance discharges. These sources have been proven on our test bench accelerator which has been upgraded to also allow us to test atomic hydrogen effusive targets. We have thus made substantial progress toward our goal of studying single electron capture from atomic hydrogen by doubly-ionized helium. A research plan for the upcoming year is also presented.

  17. Capturing Thoughts, Capturing Minds?

    DEFF Research Database (Denmark)

    Nielsen, Janni

    2004-01-01

    Think Aloud is cost effective, promises access to the user's mind and is the applied usability technique. But 'keep talking' is difficult, besides, the multimodal interface is visual not verbal. Eye-tracking seems to get around the verbalisation problem. It captures the visual focus of attention...

  18. Probabilities and energies to obtain the counting efficiency of electron-capture nuclides. KLMN model; Probabilidades y energias de reestructuracion atomica subsiguientes a la captura electronica. Modelo KLMN

    Energy Technology Data Exchange (ETDEWEB)

    Galiano, G.; Grau, A.

    1994-07-01

    An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electro capture in the counting efficiency when the atomic number of the nuclide is high. (Author)

  19. Anatomical mercury speciation in bay scallops by thio-bearing chelating resin concentration and GC-electron capture detector determination.

    Science.gov (United States)

    Zhang, Qihua; Yang, Guipeng

    2014-01-01

    The highly toxic methyl-, ethyl- and phenylmercury species that may exist in the three main anatomical parts - the adductor muscle, the mantle and the visceral mass - of bay scallops (Argopecten irradias) were quantitatively released by cupric chloride, zinc acetate, sodium chloride and hydrochloric acid (HCl) under ultrasonic extraction. After centrifugation, the mercury species in the supernatant were concentrated by thio (SH)-bearing chelating resins, eluted with HClO4 and HCl and extracted with toluene. Separation was achieved by capillary GC equipped with programmed temperatures, a constant nitrogen flow and detected by a micro-electron capture detector (μECD). Under optimised conditions, the LODs for methyl-, ethyl- and phenylmercury in bay scallop samples were 1.1, 0.65 and 0.80 ng g(-1), respectively. The maximum RSD for three replicate determinations of methyl-, ethyl- and phenylmercury in bay scallop samples were 13.7%, 14.0% and 11.2%, respectively. In the concentration range of 4-200 ng g(-1) in bay scallop samples, the calibration graphs were linear with correlation coefficients not less than 0.997. Recoveries for spiked samples were in the range of 92.7-103.5% (methylmercury), 87.5-108.3% (ethylmercury) and 91.6-106.0% (phenylmercury), respectively. The method was verified by the determination of methylmercury in a CRM GBW10029 (Total Mercury and Methyl Mercury in Fish Tissue), with results in good agreement with the certified values. Methylmercury - the only existing species in bay scallops - was successfully determined by the method.

  20. Determination of the Electron Self-Exchange Rates of Blue Copper Proteins by Super-WEFT NMR Spectroscopy

    DEFF Research Database (Denmark)

    Ma, Lixin; Philipp, Else Astrid; Led, Jens J.

    2001-01-01

    Anabaena variabilis plastocyanin, blue copper proteins, electron self-exchange rates, electron transfer, super-WEFT NMR......Anabaena variabilis plastocyanin, blue copper proteins, electron self-exchange rates, electron transfer, super-WEFT NMR...

  1. The influence of hook type, angler experience, and fish size on injury rates and the duration of capture in an Alaskan catch-and-release rainbow trout fishery

    Science.gov (United States)

    Meka, J.M.

    2004-01-01

    Owing to concerns about the high incidence of past hooking injuries in Alagnak River rainbow trout Oncorhynchus mykiss, fish were captured with spin- and fly-fishing gear with barbed and barbless circle and "J" hooks to determine gear types contributing to injury. Landing and hook removal times were measured for a portion of fish captured, and the anatomical hooking location, hooking scar locations, bleeding intensity, angler experience, and fish size were recorded for all captured fish. Approximately 62% of fish captured experienced at least one new hooking injury, and 29% of fish had at least one past hooking injury. Small fish sustained higher new injury and bleeding rates, but large fish had higher past injury rates. Injury rates were higher for barbed J hooks, barbed J hooks took longer to remove, and fish caught by spin-fishing were injured more frequently than fish caught by fly-fishing. Fewer fly-fishing-caught fish were injured using circle hooks, and circle hooks tended to hook fish in only one location, generally in the jaw. Barbed J hooks were more efficient at landing fish, and J hooks were more efficient at landing fish than circle hooks. Novice anglers injured proportionally more fish than experienced anglers, primarily during hook removal. Landing time was positively correlated with fish size, and experienced anglers took longer to land fish than novices because they captured larger fish. These results suggest that a reduction in hooking injuries may be achieved by using circle hooks as an alternative to J hooks and barbless J hooks to reduce injury and handling time, yet catch efficiency for both methods would be reduced. Although fish captured with barbless J hooks and circle hooks had fewer injuries, it is important to note that each hook type also caused significant injury, and angler education is recommended to promote proper hook removal techniques.

  2. DETERMINATION OF HETEROGENEOUS ELECTRON TRANSFER RATE CONSTANTS AT MICROFABRICATED IRIDIUM ELECTRODES. (R825511C022)

    Science.gov (United States)

    There has been an increasing use of both solid metal and microfabricated iridium electrodes as substrates for various types of electroanalysis. However, investigations to determine heterogeneous electron transfer rate constants on iridium, especially at an electron beam evapor...

  3. DETERMINATION OF HETEROGENEOUS ELECTRON TRANSFER RATE CONSTANTS AT MICROFABRICATED IRIDIUM ELECTRODES. (R825511C022)

    Science.gov (United States)

    There has been an increasing use of both solid metal and microfabricated iridium electrodes as substrates for various types of electroanalysis. However, investigations to determine heterogeneous electron transfer rate constants on iridium, especially at an electron beam evapor...

  4. Design and simulation of rate-based CO2 capture processes using carbonic anhydrase (CA) applied to biogas

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Gaspar, Jozsef; Jacobsen, Bjartur

    2017-01-01

    a potential to create negative emissions using bio-energy carbon capture and storage (BECCS). All sectors are still in the need for applying more sustainable carbon capture and storage (CCS) technologies which result in lower energy consumption while reducing the impact on the environment. Recently several....... The advantage is a noticeably lower regeneration energy compared to primary and secondary amines. As a result the cost for stripping is significantly lower. Reactivated slow tertiary amines are applied in this study with the aim of reducing energy consumption. This is achieved byusing carbonic anhydrase (CA...

  5. Spatially dependent electron-positron pair creation rate

    Science.gov (United States)

    Lv, Q. Z.; Unger, J.; Li, Y. T.; Su, Q.; Grobe, R.

    2016-11-01

    The vacuum breakdown process in an inhomogeneous supercritical electric field of finite extension is examined. By probing the electron-positron pair creation zone with incoming electrons that have controlled velocities, we can address the fundamental question of where the electrons are being created from the vacuum. In contrast to what one might expect, the spatial regions of most likely pair creation are not necessarily those where the electric-field strength is largest. In fact, the creation regions are determined solely by energetic considerations and particles can therefore be created in spatial regions where the local field strength is far below the Schwinger threshold. These predictions are also supported independently by spatial probability densities obtained by extrapolation as well as by classical and quantum-mechanical analysis.

  6. Double electron capture in collisions of the helium-like ions N/sup 5+/, O/sup 6+/ and Ne/sup 8+/ with helium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Boudjema, M.; Moretto-Capelle, P.; Bordenave-Montesquieu, A. and others

    1989-03-28

    A fitting procedure of 1s/sup 2/3l3l' lines observed in A/sup (z-2)+/(1s/sup 2/)+He collisions (Z = 7, 8 and 10), at 10 q keV collision energy (q = Z -2) and 10/sup 0/ observation angle, allows us to compare new theoretical positions and lifetimes, and experimental electron spectra. It is found that the spin conservation rule holds and that only singlet states are populated in these capture processes. As in N/sup 7+/ and O/sup 8+/ + He systems, capture into the highest angular momentum /sup 1/G state is favoured in O/sup 6+/ and Ne/sup 8+/ + He systems and accounts for 26% of the double capture at 10/sup 0/. In N/sup 5+/ + He, the L distribution is broader and no L value is clearly predominant.

  7. A Measurement of the Rate of Muon Capture in Hydrogen Gas andDetermination of the Proton's Induced Pseudoscalar Coupling gP

    Energy Technology Data Exchange (ETDEWEB)

    Banks, Thomas Ira [Univ. of California, Berkeley, CA (United States)

    2007-07-01

    This dissertation describes a measurement of the rate ofnuclear muon capture by the proton, performed by the MuCap Collaborationusing a new technique based on a time projection chamber operating inultraclean, deuterium-depleted hydrogen gas at room temperature and 1 MPapressure. The hydrogen target's low gas density of 1 percent compared toliquid hydrogen is key to avoiding uncertainties that arise from theformation of muonic molecules. The capture rate was obtained from thedifference between the μ- disappearance rate in hydrogen--as determinedfrom data collected in the experiment's first physics run in fall2004--and the world averagefor the μ+ decay rate. After combining theresults of my analysis with the results from another independent analysisof the 2004 data, the muon capture rate from the hyperfine singlet groundstate of the mu-p atom is found to be ΛS = 725.0 ± 17.4 1/s, fromwhich the induced pseudoscalar coupling of the nucleon, gP(q2 = -0.88m$2\\atop{μ}$)= 7.3 ± 1.1, is extracted. This result for gP is consistent withtheoretical predictions that are based on the approximate chiral symmetryof QCD.

  8. Excited states in the doubly odd 168Lu nucleus fed by electron-capture decay of 168Hf (T1/2=25.95 min)

    Science.gov (United States)

    Barci, V.; Ardisson, G.; Trubert, D.; Hussonnois, M.

    1997-05-01

    The low-spin levels of the odd-odd nucleus 168Lu from 168Hf (T1/2=25.95 min) electron-capture decay were investigated by direct γ and γ-γ coincidence measurements. The sources of 168Hf were produced with the 156Gd(16O,4n) reaction and radiochemically separated using chromatographic methods. A level scheme of 39 new levels in the 168Lu nucleus was proposed, accounting for 107 of 119 observed γ transitions assigned to 168Hf electron-capture decay. Transition multipolarities, level-spins, and parities were deduced or proposed. A tentative decay scheme was proposed. Level structure was discussed in the framework of the particle-rotor and Nilsson models.

  9. A split-step method to include electron-electron collisions via Monte Carlo in multiple rate equation simulations

    Science.gov (United States)

    Huthmacher, Klaus; Molberg, Andreas K.; Rethfeld, Bärbel; Gulley, Jeremy R.

    2016-10-01

    A split-step numerical method for calculating ultrafast free-electron dynamics in dielectrics is introduced. The two split steps, independently programmed in C++11 and FORTRAN 2003, are interfaced via the presented open source wrapper. The first step solves a deterministic extended multi-rate equation for the ionization, electron-phonon collisions, and single photon absorption by free-carriers. The second step is stochastic and models electron-electron collisions using Monte-Carlo techniques. This combination of deterministic and stochastic approaches is a unique and efficient method of calculating the nonlinear dynamics of 3D materials exposed to high intensity ultrashort pulses. Results from simulations solving the proposed model demonstrate how electron-electron scattering relaxes the non-equilibrium electron distribution on the femtosecond time scale.

  10. Engineered electron-transfer chain in photosystem 1 based photocathodes outperforms electron-transfer rates in natural photosynthesis.

    Science.gov (United States)

    Kothe, Tim; Pöller, Sascha; Zhao, Fangyuan; Fortgang, Philippe; Rögner, Matthias; Schuhmann, Wolfgang; Plumeré, Nicolas

    2014-08-25

    Photosystem 1 (PS1) triggers the most energetic light-induced charge-separation step in nature and the in vivo electron-transfer rates approach 50 e(-)  s(-1)  PS1(-1). Photoelectrochemical devices based on this building block have to date underperformed with respect to their semiconductor counterparts or to natural photosynthesis in terms of electron-transfer rates. We present a rational design of a redox hydrogel film to contact PS1 to an electrode for photocurrent generation. We exploit the pH-dependent properties of a poly(vinyl)imidazole Os(bispyridine)2Cl polymer to tune the redox hydrogel film for maximum electron-transfer rates under optimal conditions for PS1 activity. The PS1-containing redox hydrogel film displays electron-transfer rates of up to 335±14 e(-)  s(-1)  PS1(-1), which considerably exceeds the rates observed in natural photosynthesis or in other semiartificial systems. Under O2 supersaturation, photocurrents of 322±19 μA cm(-2) were achieved. The photocurrents are only limited by mass transport of the terminal electron acceptor (O2). This implies that even higher electron-transfer rates may be achieved with PS1-based systems in general. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Kuang's Semi-Classical Formalism for Electron Capture Cross-Sections in Ion-Ion Collisions at few MeV's/nucleon: Application to ENA Modeling

    Science.gov (United States)

    Barghouty, A. F.

    2012-01-01

    Accurate estimates of electron-capture cross sections at energies relevant to energetic neutral atom (ENA) modeling (approx few MeV per nucleon) and for multi-electron ions must rely on first-principles approaches and/or detailed quantum-mechanical simulation of the collision process. Kuang's semi-classical approach offers a middle-ground, elegant and efficient way to arrive at these estimates. We shall present a sample application and current progress in applying and extending Kuang's formalism to ENA modeling.

  12. A new method for estimating morbidity rates based on routine electronic medical records in primary care

    NARCIS (Netherlands)

    Nielen, M.; Spronk, I.; Davids, R.; Korevaar, J.; Poos, R.; Hoeymans, N.; Opstelten, W.; Sande, M. van der; Biermans, M.; Schellevis, F.; Verheij, R.

    2016-01-01

    Background & Aim: Routinely recorded electronic health records (EHRs) from general practitioners (GPs) are increasingly available and provide valuable data for estimating incidence and prevalence rates of diseases in the general population. Valid morbidity rates are essential for patient management

  13. Validation of a new hand-held electronic data capture method for continuous monitoring of subjective appetite sensations

    Directory of Open Access Journals (Sweden)

    King Neil

    2011-06-01

    Full Text Available Abstract Background When large scale trials are investigating the effects of interventions on appetite, it is paramount to efficiently monitor large amounts of human data. The original hand-held Electronic Appetite Ratings System (EARS was designed to facilitate the administering and data management of visual analogue scales (VAS of subjective appetite sensations. The purpose of this study was to validate a novel hand-held method (EARS II (HP® iPAQ against the standard Pen and Paper (P&P method and the previously validated EARS. Methods Twelve participants (5 male, 7 female, aged 18-40 were involved in a fully repeated measures design. Participants were randomly assigned in a crossover design, to either high fat (>48% fat or low fat (ad libitum lunch was provided immediately before completing a final set of appetite sensations. Results Repeated measures ANOVAs were conducted for ratings of hunger, fullness and desire to eat. There were no significant differences between P&P compared with either EARS or EARS II (p > 0.05. Correlation coefficients between P&P and EARS II, controlling for age and gender, were performed on Area Under the Curve ratings. R2 for Hunger (0.89, Fullness (0.96 and Desire to Eat (0.95 were statistically significant (p Conclusions EARS II was sensitive to the impact of a meal and recovery of appetite during the postprandial period and is therefore an effective device for monitoring appetite sensations. This study provides evidence and support for further validation of the novel EARS II method for monitoring appetite sensations during large scale studies. The added versatility means that future uses of the system provides the potential to monitor a range of other behavioural and physiological measures often important in clinical and free living trials. This study was registered as a clinical trial by Current Controlled Trials (Registration Number - ISRCTN47291569.

  14. A multi-channel opto-electronic sensor to accurately monitor heart rate against motion artefact during exercise.

    Science.gov (United States)

    Alzahrani, Abdullah; Hu, Sijung; Azorin-Peris, Vicente; Barrett, Laura; Esliger, Dale; Hayes, Matthew; Akbare, Shafique; Achart, Jérôme; Kuoch, Sylvain

    2015-10-12

    This study presents the use of a multi-channel opto-electronic sensor (OEPS) to effectively monitor critical physiological parameters whilst preventing motion artefact as increasingly demanded by personal healthcare. The aim of this work was to study how to capture the heart rate (HR) efficiently through a well-constructed OEPS and a 3-axis accelerometer with wireless communication. A protocol was designed to incorporate sitting, standing, walking, running and cycling. The datasets collected from these activities were processed to elaborate sport physiological effects. t-test, Bland-Altman Agreement (BAA), and correlation to evaluate the performance of the OEPS were used against Polar and Mio-Alpha HR monitors. No differences in the HR were found between OEPS, and either Polar or Mio-Alpha (both p > 0.05); a strong correlation was found between Polar and OEPS (r: 0.96, p heart rate.

  15. Electron diffraction using ultrafast electron bunches from a laser-wakefield accelerator at kHz repetition rate

    Science.gov (United States)

    He, Z.-H.; Thomas, A. G. R.; Beaurepaire, B.; Nees, J. A.; Hou, B.; Malka, V.; Krushelnick, K.; Faure, J.

    2013-02-01

    We show that electron bunches in the 50-100 keV range can be produced from a laser wakefield accelerator using 10 mJ, 35 fs laser pulses operating at 0.5 kHz. It is shown that using a solenoid magnetic lens, the electron bunch distribution can be shaped. The resulting transverse and longitudinal coherence is suitable for producing diffraction images from a polycrystalline 10 nm aluminum foil. The high repetition rate, the stability of the electron source, and the fact that its uncorrelated bunch duration is below 100 fs make this approach promising for the development of sub-100 fs ultrafast electron diffraction experiments.

  16. READOUT ELECTRONICS FOR A HIGH-RATE CSC DETECTOR

    Energy Technology Data Exchange (ETDEWEB)

    OCONNOR,P.; GRATCHEV,V.; KANDASAMY,A.; POLYCHRONAKOS,V.; TCHERNIATINE,V.; PARSONS,J.; SIPPACH,W.

    1999-09-25

    A readout system for a high-rate muon Cathode Strip Chamber (CSC) is described. The system, planned for use in the forward region of the ATLAS muon spectrometer, uses two custom CMOS integrated circuits to achieve good position resolution at a flux of up to 2,500 tracks/cm{sup 2}/s.

  17. Boundary-corrected four-body continuum-intermediate-state method: Single-electron capture from heliumlike atomic systems by fast nuclei

    Science.gov (United States)

    Mančev, Ivan; Milojević, Nenad; Belkić, Dževad

    2015-06-01

    Single charge exchange in collisions between bare projectiles and heliumlike atomic systems at intermediate and high incident energies is examined by using the four-body formalism of the first- and second-order theories. The main purpose of the present study is to investigate the relative importance of the intermediate ionization continua of the captured electron compared to the usual direct path of the single electron transfer from a target to a projectile. In order to achieve this goal, comprehensive comparisons are made between the four-body boundary-corrected continuum-intermediate-states (BCIS-4B) method and the four-body boundary-corrected first Born (CB1-4B) method. The perturbation potential is the same in the CB1-4B and BCIS-4B methods. Both methods satisfy the correct boundary conditions in the entrance and exit channels. However, unlike the CB1-4B method, the second-order BCIS-4B method takes into account the electronic Coulomb continuum-intermediate states in either the entrance or the exit channel depending on whether the post or the prior version of the transition amplitude is used. Hence, by comparing the results from these two theories, the relative importance of the intermediate ionization electronic continua can be assessed within the four-body formalism of scattering theory. The BCIS-4B method predicts the usual second-order effect through double scattering of the captured electron on two nuclei as a quantum-mechanical counterpart of the Thomas classical two-step, billiard-type collision. The physical mechanism for this effect in the BCIS-4B method is also comprised of two steps such that ionization occurs first. This is followed by capture of the electron by the projectile with both processes taking place on the energy shell. Moreover, the role of the second, noncaptured electron in a heliumlike target is revisited. To this end, the BCIS-4B method describes the effect of capture of one electron by the interaction of the projectile nucleus with

  18. Study of electronic prescribing rates and barriers identified among providers using electronic health records in New York City

    Directory of Open Access Journals (Sweden)

    Sam Amirfar

    2011-05-01

    Conclusions The data gathered from our providers indicate that there is an increasing trend in the eRx rate to 27.5% by July 2010, but still short of the 40% meaningful use level. However, obstacles to increased rates remain primarily providers' belief that many patients prefer paper prescriptions and many pharmacies are not yet prepared to accept electronic prescriptions.

  19. Energy and charge dependence of the rate of electron-ion recombination in cold magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Gao, H.; Schuch, R.; Zong, W.; Justiniano, E.; DeWitt, D.R.; Lebius, H.; Spies, W. [Stockholm Univ., Atomic Physics Dept., Stockholm (Sweden)

    1997-07-28

    We have measured electron-ion recombination rates for bare ions of D{sup +}, He{sup 2+}, N{sup 7+}, Ne{sup 10+} and Si{sup 14+} in a storage ring. For the multi-charged ions an unexpected energy dependence was found, showing a strong increase of the measured rates over the calculated radiative recombination rate for electron beam detuning energies below the electron beam transverse temperature. The measured enhanced rates increase approximately as Z{sup 2.8} with the charge state Z. A comparison of these rates with theoretical predictions for collisional-radiative recombination in the cold magnetized electron plasma, in particular three-body recombination including radiative de-excitation of electrons in Rydberg levels, is made. (author).

  20. Improving Prediction Accuracy of a Rate-Based Model of an MEA-Based Carbon Capture Process for Large-Scale Commercial Deployment

    Directory of Open Access Journals (Sweden)

    Xiaobo Luo

    2017-04-01

    Full Text Available Carbon capture and storage (CCS technology will play a critical role in reducing anthropogenic carbon dioxide (CO2 emission from fossil-fired power plants and other energy-intensive processes. However, the increment of energy cost caused by equipping a carbon capture process is the main barrier to its commercial deployment. To reduce the capital and operating costs of carbon capture, great efforts have been made to achieve optimal design and operation through process modeling, simulation, and optimization. Accurate models form an essential foundation for this purpose. This paper presents a study on developing a more accurate rate-based model in Aspen Plus® for the monoethanolamine (MEA-based carbon capture process by multistage model validations. The modeling framework for this process was established first. The steady-state process model was then developed and validated at three stages, which included a thermodynamic model, physical properties calculations, and a process model at the pilot plant scale, covering a wide range of pressures, temperatures, and CO2 loadings. The calculation correlations of liquid density and interfacial area were updated by coding Fortran subroutines in Aspen Plus®. The validation results show that the correlation combination for the thermodynamic model used in this study has higher accuracy than those of three other key publications and the model prediction of the process model has a good agreement with the pilot plant experimental data. A case study was carried out for carbon capture from a 250 MWe combined cycle gas turbine (CCGT power plant. Shorter packing height and lower specific duty were achieved using this accurate model.

  1. Rate constants of reactions of {kappa}-carrageenan with hydrated electron and hydroxyl radical

    Energy Technology Data Exchange (ETDEWEB)

    Abad, L.V. [Nuclear Professional School, School of Engineering Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Philippine Nuclear Research Institute, Commonwealth Avenue, Diliman, Quezon City (Philippines)], E-mail: lvabad@pnri.dost.gov.ph; Saiki, S.; Kudo, H.; Muroya, Y.; Katsumura, Y. [Nuclear Professional School, School of Engineering Laboratory, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Rosa, A.M. de la [Philippine Nuclear Research Institute, Commonwealth Avenue, Diliman, Quezon City (Philippines)

    2007-12-15

    The rate constants for the reactions of {kappa}-carrageenan with hydrated electron and hydroxyl radical was investigated by pulse radiolysis and laser photolysis. The kinetics of the reaction of hydrated electron indicates no seeming reaction with {kappa}-carrageenan. On the other hand, hydroxyl radical reacts very rapidly with {kappa}-carrageenan at a rate constant of approximately 1.2 x 10{sup 9} M{sup -1} s{sup -1}. This rate constant varies with pH.

  2. The astrophysical r-process and its dependence on properties of nuclei far from stability beta strength functions and neutron capture rates

    CERN Document Server

    Klapdor-Kleingrothaus, H V; Metzinger, J; Oda, T; Thielemann, F K

    1981-01-01

    It is shown that the astrophysical r-process and the question of its site are very sensitive to 'standard' nuclear physics parameters like the beta decay properties and neutron capture rates. Since for these quantities in almost all r-process calculations up to now, and also in all estimates of the production rates of chronometric pairs, only very rough assumptions have been made, it is attempted to present procedures which put the calculation of these quantities for nuclei far from stability on a reliable physical basis. This is done by a microscopic description of the beta strength function and by using a statistical model based on a 'next to first principles' optical potential including effects of deformation for the neutron capture rates. The beta -decay rates for approximately 6000 nuclei between the beta -stability line and the neutron drip line are calculated. The heavy element synthesis by explosive He burning then is calculated using these beta -rates and using realistic star models treating the supe...

  3. The AtChem On-line model and Electronic Laboratory Notebook (ELN): A free community modelling tool with provenance capture

    Science.gov (United States)

    Young, J. C.; Boronska, K.; Martin, C. J.; Rickard, A. R.; Vázquez Moreno, M.; Pilling, M. J.; Haji, M. H.; Dew, P. M.; Lau, L. M.; Jimack, P. K.

    2010-12-01

    AtChem On-line1 is a simple to use zero-dimensional box modelling toolkit, developed for use by laboratory, field and chamber scientists. Any set of chemical reactions can be simulated, in particular the whole Master Chemical Mechanism (MCM2) or any subset of it. Parameters and initial data can be provided through a self-explanatory web form and the resulting model is compiled and run on a dedicated server. The core part of the toolkit, providing a robust solver for thousands of chemical reactions, is written in Fortran and uses SUNDIALS3 CVODE libraries. Chemical systems can be constrained at multiple, user-determined timescales; this enabled studies of radical chemistry at one minute timescales. AtChem On-line is free to use and requires no installation - a web browser, text editor and any compressing software is all the user needs. CPU and storage are provided by the server (input and output data are saved indefinitely). An off-line version is also being developed, which will provide batch processing, an advanced graphical user interface and post-processing tools, for example, Rate of Production Analysis (ROPA) and chainlength analysis. The source code is freely available for advanced users wishing to adapt and run the program locally. Data management, dissemination and archiving are essential in all areas of science. In order to do this in an efficient and transparent way, there is a critical need to capture high quality metadata/provenance for modelling activities. An Electronic Laboratory Notebook (ELN) has been developed in parallel with AtChem Online as part of the EC EUROCHAMP24 project. In order to use controlled chamber experiments to evaluate the MCM, we need to be able to archive, track and search information on all associated chamber model runs, so that they can be used in subsequent mechanism development. Therefore it would be extremely useful if experiment and model metadata/provenance could be easily and automatically stored electronically

  4. Electron impact excitation rates for transitions in Mg V

    CERN Document Server

    Aggarwal, K M

    2016-01-01

    Energy levels, radiative rates (A-values) and lifetimes, calculated with the GRASP code, are reported for an astrophysically important O-like ion Mg~V. Results are presented for transitions among the lowest 86 levels belonging to the 2s$^2$2p$^4$, 2s2p$^5$, 2p$^6$, and 2s$^2$2p$^3$3$\\ell$ configurations. There is satisfactory agreement with earlier data for most levels/transitions, but scope remains for improvement. Collision strengths are also calculated, with the DARC code, and the results obtained are comparable for most transitions (at energies above thresholds) with earlier work using the DW code. In thresholds region, resonances have been resolved in a fine energy mesh to determine values of effective collision strengths ($\\Upsilon$) as accurately as possible. Results are reported for all transitions at temperatures up to 10$^6$~K, which should be sufficient for most astrophysical applications. However, a comparison with earlier data reveals discrepancies of up to two orders of magnitude for over 60\\% o...

  5. Injection deep level transient spectroscopy: An improved method for measuring capture rates of hot carriers in semiconductors

    Science.gov (United States)

    Fleming, R. M.; Seager, C. H.; Lang, D. V.; Campbell, J. M.

    2015-07-01

    An improved method for measuring the cross sections for carrier trapping at defects in semiconductors is described. This method, a variation of deep level transient spectroscopy (DLTS) used with bipolar transistors, is applied to hot carrier trapping at vacancy-oxygen, carbon-oxygen, and three charge states of divacancy centers (V2) in n- and p-type silicon. Unlike standard DLTS, we fill traps by injecting carriers into the depletion region of a bipolar transistor diode using a pulse of forward bias current applied to the adjacent diode. We show that this technique is capable of accurately measuring a wide range of capture cross sections at varying electric fields due to the control of the carrier density it provides. Because this technique can be applied to a variety of carrier energy distributions, it should be valuable in modeling the effect of radiation-induced generation-recombination currents in bipolar devices.

  6. Relativistic electron beams driven by single-cycle laser pulses at kHz repetition rate (Conference Presentation)

    Science.gov (United States)

    Faure, Jérôme; Guénot, Diego; Gustas, Dominykas; Vernier, Aline; Beaurepaire, Benoît; Böhle, Frederik; López-Martens, Rodrigo; Lifschitz, Agustin

    2017-05-01

    Laser-plasma accelerators are usually driven by 100-TW class laser systems with rather low repetition rates. However, recent years have seen the emergence of laser-plasma accelerators operating with kHz lasers and energies lower than 10 mJ. The high repetition-rate is particularly interesting for applications requiring high stability and high signal-to-noise ratio but lower energy electrons. For example, our group recently demonstrated that kHz laser-driven electron beams could be used to capture ultrafast structural dynamics in Silicon nano-membranes via electron diffraction with picosecond resolution. In these first experiments, electrons were injected in the density gradients located at the plasma exit, resulting in rather low energies in the 100 keV range. The electrons being nonrelativistic, the bunch duration quickly becomes picosecond long. Relativistic energies are required to mitigate space charge effects and maintain femtosecond bunches. In this paper, we will show very recent results where electrons are accelerated in laser-driven wakefields to relativistic energies, reaching up to 5 MeV at kHz repetition rate. The electron energy was increased by nearly two orders of magnitude by using single-cycle laser pulses of 3.5 fs, with only 2.5 mJ of energy. Using such short pulses of light allowed us to resonantly excite high amplitude and nonlinear plasma waves at high plasma density, ne=1.5-2×1020 cm-3, in a regime close to the blow-out regime. Electrons had a peaked distribution around 5 MeV, with a relative energy spread of 30 %. Charges in the 100's fC/shot and up to pC/shot where measured depending on plasma density. The electron beam was fairly collimated, 20 mrad divergence at Full Width Half Maximum. The results show remarkable stability of the beam parameters in terms of beam pointing and electron distribution. 3D PIC simulations reproduce the results very well and indicate that electrons are injected by the ionization of Nitrogen atoms, N5+ to N6

  7. Electron-phonon coupling in high-temperature cuprate superconductors determined from electron relaxation rates.

    Science.gov (United States)

    Gadermaier, C; Alexandrov, A S; Kabanov, V V; Kusar, P; Mertelj, T; Yao, X; Manzoni, C; Brida, D; Cerullo, G; Mihailovic, D

    2010-12-17

    We determined electronic relaxation times via pump-probe optical spectroscopy using sub-15 fs pulses for the normal state of two different cuprate superconductors. We show that the primary relaxation process is the electron-phonon interaction and extract a measure of its strength, the second moment of the Eliashberg function λ[ω2] = 800 ± 200 meV2 for La(1.85)Sr(0.15)CuO4 and λ[ω2] = 400 ± 100 meV2 for YBa(2)Cu(3)O(6.5). These values suggest a possible fundamental role of the electron-phonon interaction in the superconducting pairing mechanism.

  8. Preparatory studies for a high-precision Penning-trap measurement of the {sup 163}Ho electron capture Q-value

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, F. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Johannes Gutenberg-Universitaet, Institut fuer Physik, Mainz (Germany); Beyer, T.; Blaum, K.; Eibach, M.; Eliseev, S.; Nagy, Sz. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Block, M. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Chenmarev, S.; Novikov, Yu.N. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Saint Petersburg State University, Physical Faculty, Saint Petersburg (Russian Federation); Dorrer, H. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Paul Scherrer Institute, Villigen (Switzerland); Universitaet Bern, Bern (Switzerland); Duellmann, C.E. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Eberhardt, K. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Grund, J. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Koester, U. [Institut Laue-Langevin, Grenoble (France); Renisch, D. [Johannes Gutenberg-Universitaet, Institut fuer Kernchemie, Mainz (Germany); Tuerler, A. [Paul Scherrer Institute, Villigen (Switzerland); Universitaet Bern, Bern (Switzerland); Wendt, K. [Johannes Gutenberg-Universitaet, Institut fuer Physik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany)

    2015-07-15

    The ECHo Collaboration (Electron Capture {sup 163}Ho) aims to investigate the calorimetric spectrum following the electron capture decay of {sup 163}Ho to determine the mass of the electron neutrino. The size of the neutrino mass is reflected in the endpoint region of the spectrum, i.e., the last few eV below the transition energy. To check for systematic uncertainties, an independent determination of this transition energy, the Q-value, is mandatory. Using the TRIGA-TRAP setup, we demonstrate the feasibility of performing this measurement by Penning-trap mass spectrometry. With the currently available, purified {sup 163}Ho sample and an improved laser ablation mini-RFQ ion source, we were able to perform direct mass measurements of {sup 163}Ho and {sup 163}Dy with a sample size of less than 10{sup 17} atoms. The measurements were carried out by determining the ratio of the cyclotron frequencies of the two isotopes to those of carbon cluster ions using the time-of-flight ion cyclotron resonance method. The obtained mass excess values are ME({sup 163}Ho)= -66379.3(9) keV and ME({sup 163}Dy)= -66381.7(8) keV. In addition, the Q-value was measured for the first time by Penning-trap mass spectrometry to be Q = 2.5(7) keV. (orig.)

  9. An electronic flow control system for a variable-rate tree sprayer

    Science.gov (United States)

    Precise modulation of nozzle flow rates is a critical measure to achieve variable-rate spray applications. An electronic flow rate control system accommodating with microprocessors and pulse width modulation (PWM) controlled solenoid valves was designed to manipulate the output of spray nozzles inde...

  10. Liquid scintillation counting efficiency in three photomultiplier systems. Pure electron capture; Eficiencia de recuento por centelleo liquido en sistemas con tres fotomultiplicadores. Captura electronica pura

    Energy Technology Data Exchange (ETDEWEB)

    Los Arcos, J. M.; Grau Carles, A.; Grau Malonda, A.

    1990-07-01

    The tables of counting efficiency as a function of the figure of merit for a liquid scintillation counting system working with three phototubes are presented. The evaluation has been carried out for a Toluene-based scintillator with 5, 10 and 15 ml column, and 19 different radionuclides decaying by pure electron capture: 37Ar 41Ca, 49V, 53 Mn, 55Fe, 59Ni, 68Ge 7iGe, 82Sr, 97Tc, 118Te, 131CS, 137La, 140Ca, 157Tb, 165Er, 193Pt, 194Hg, 205Pb. (Author) 22 refs.

  11. Rapid and sensitive electron-capture gas chromatographic method for the determination of pinazepam and its metabolites in human plasma, urine and milk.

    Science.gov (United States)

    Pacifici, G M; Placidi, G F

    1977-05-11

    A rapid, sensitive and specific gas-liquid chromatographic method for the measurement of pinazepam and its metabolites in biological fluids is reported. After a single extraction of the sample with toluene, the organic phase is concentrated and, after chromatography on a 3% OV-17 column, measured with an electron-capture detector. The sensitivity was 1.0 ng/ml for pinazepam and 5.0 ng/ml for its metabolites. Plasma levels and urinary excretion in human volunteers and plasma and milk levels in women suffering from anxiety during breastfeeding are reported.

  12. Direct measurement of stellar neutron capture rates of 14C and comparison with the Coulomb breakup method

    Science.gov (United States)

    Reifarth, Rene; Heil, M.; Plag, R.; Besserer, U.; Couture, A.; Dababneh, S.; Dörr, L.; Forssén, C.; Görres, J.; Haight, R. C.; Mengoni, A.; O'Brien, S.; Patronis, N.; Rundberg, R. S.; Uberseder, E.; Wiescher, M.; Wilhelmy, J. B.

    The neutron capture cross section of 14 C has been shown to be important for several neutron driven nucleosynthesis scenarios. Due to the high neutron abundance it is expected that the 14 C(n,γ) reaction competes strongly with other neutron-induced reactions on 14 C. The 14 C(n,γ) reaction is also important to validate (n,γ) cross sections obtained via the inverse reaction by the Coulomb breakup method. In principle, 14 C belongs to the few cases where this correspondence can be validated in a convincingly clean way. So far, the example of 14 C is obscured, however, by discrepancies between several experiments and theory. In this contribution we report on a re- analysis of the direct measurements of the 14 C(n,γ) reaction presented on the last NIC conference (Vancouver, 2004). The neutron energies used during the experiment ranged from 30 to 800 keV. The earlier presented disagreement between the direct measurements and the Coulomb breakup method has been resolved.

  13. Numerical modeling of radioactive neutron capture influence of Hf isotopic composition dynamics rate in the RBMK-1500 reactor

    CERN Document Server

    Jurkevicius, A; Auzelyte, V; Remeikis, V

    2000-01-01

    The nuclide composition of the nuclear fuel and isotopic composition of the hafnium in the radial neutron flux detectors of the RBMK-1500 reactor were numerically modelled. The sequence SAS2 from package SCALE 4.3 was used for calculations. The nuclear fuel nuclide concentrations, the concentration of Hf isotopes, the neutron absorption rate on Hf isotopes and summary absorption rate dependences on the fuel assembly burn up are presented. (author)

  14. Resummed jet rates with heavy quarks in electron-positron collisions

    OpenAIRE

    Rodrigo, German; Krauss, Frank

    2003-01-01

    Expressions for Sudakov form factors for heavy quarks are presented. They are used to construct resummed jet rates in electron-positron annihilation. Predictions are given for production of bottom quarks at LEP and top quarks at the Linear Collider.

  15. Monte Carlo analysis of the long-lived fission product neutron capture rates at the Transmutation by Adiabatic Resonance Crossing (TARC) experiment

    Energy Technology Data Exchange (ETDEWEB)

    Abanades, A., E-mail: abanades@etsii.upm.es [Grupo de Modelizacion de Sistemas Termoenergeticos, ETSII, Universidad Politecnica de Madrid, c/Ramiro de Maeztu, 7, 28040 Madrid (Spain); Alvarez-Velarde, F.; Gonzalez-Romero, E.M. [Centro de Investigaciones Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense, 40, Ed. 17, 28040 Madrid (Spain); Ismailov, K. [Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Lafuente, A. [Grupo de Modelizacion de Sistemas Termoenergeticos, ETSII, Universidad Politecnica de Madrid, c/Ramiro de Maeztu, 7, 28040 Madrid (Spain); Nishihara, K. [Transmutation Section, J-PARC Center, JAEA, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Saito, M. [Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Stanculescu, A. [International Atomic Energy Agency (IAEA), Vienna (Austria); Sugawara, T. [Transmutation Section, J-PARC Center, JAEA, Tokai-mura, Ibaraki-ken 319-1195 (Japan)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer TARC experiment benchmark capture rates results. Black-Right-Pointing-Pointer Utilization of updated databases, included ADSLib. Black-Right-Pointing-Pointer Self-shielding effect in reactor design for transmutation. Black-Right-Pointing-Pointer Effect of Lead nuclear data. - Abstract: The design of Accelerator Driven Systems (ADS) requires the development of simulation tools that are able to describe in a realistic way their nuclear performance and transmutation rate capability. In this publication, we present an evaluation of state of the art Monte Carlo design tools to assess their performance concerning transmutation of long-lived fission products. This work, performed under the umbrella of the International Atomic Energy Agency, analyses two important aspects for transmutation systems: moderation on Lead and neutron captures of {sup 99}Tc, {sup 127}I and {sup 129}I. The analysis of the results shows how shielding effects due to the resonances at epithermal energies of these nuclides affects strongly their transmutation rate. The results suggest that some research effort should be undertaken to improve the quality of Iodine nuclear data at epithermal and fast neutron energy to obtain a reliable transmutation estimation.

  16. Two effects relevant for the study of astrophysical reaction rates: gamma transitions in capture reactions and Coulomb suppression of the stellar enhancement

    CERN Document Server

    Rauscher, T

    2008-01-01

    Nucleosynthesis processes involve reactions on several thousand nuclei, both close to and far off stability. The preparation of reaction rates to be used in astrophysical investigations requires experimental and theoretical input. In this context, two interesting aspects are discussed: (i) the relevant gamma transition energies in astrophysical capture reactions, and (ii) the newly discovered Coulomb suppression of the stellar enhancement factor. The latter makes a number of reactions with negative Q value more favorable for experimental investigation than their inverse reactions, contrary to common belief.

  17. Rate coefficients for low-energy electron dissociative attachment to molecular hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Horacek, J.; Houfek, K.; Cizek, M. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Murakami, I.; Kato, T. [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2003-02-01

    Calculation of rate constants for dissociative electron attachment to molecular hydrogen is reported. The calculation is based on an improved nonlocal resonance model of Cizek, Horacek and Domcke which takes fully into account the nonlocality of the resonance dynamics and uses potentials with correct asymptotic forms. The rate constants are calculated for all quantum numbers v and J of the target molecules and for electron temperature in the range 0-30000 K. (author)

  18. Rate of three-body electron attachment to the oxygen molecule in an externally sustained discharge

    Energy Technology Data Exchange (ETDEWEB)

    Krasyukov, A.G.; Naumov, V.G.; Shachkin, L.V.; Shashkov, V.M.

    1981-05-01

    The rate of three-body attachment of electrons to the oxygen molecule has been determined in an atmospheric-pressure discharge sustained by a fast electron beam in a O/sub 2/:N/sub 2/ = 1:20 mixture. The experimental results agree well with theoretical results derived elsewhere. The attachment rate falls off with increasing input energy. A qualitative explanation is offered for this effect.

  19. Rate coefficients for low-energy electron dissociative attachment to molecular hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Horacek, J.; Houfek, K.; Cizek, M. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Murakami, I.; Kato, T. [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2003-02-01

    Calculation of rate constants for dissociative electron attachment to molecular hydrogen is reported. The calculation is based on an improved nonlocal resonance model of Cizek, Horacek and Domcke which takes fully into account the nonlocality of the resonance dynamics and uses potentials with correct asymptotic forms. The rate constants are calculated for all quantum numbers v and J of the target molecules and for electron temperature in the range 0-30000 K. (author)

  20. Capture, Electron-Cooling and Compression of Antiprotons in a Large Penning-Trap for Physics Experiments with an Ultra-Low Energy Extracted Antiproton Beam

    CERN Multimedia

    2002-01-01

    % PS200 \\\\ \\\\The availability of ultra-low energy antiprotons is a crucial ingredient for the execution of the gravity measurements PS200. We have developed a method to provide such low energy antiprotons based on a large Penning trap (the PS200 catching trap). This system can accept a fast-extracted pulse from LEAR, reduce the energy of the antiprotons in the pulse from 5.9~MeV to several tens of kilovolts using a degrading foil, and then capture the antiprotons in a large Penning trap. These antiprotons are cooled by electrons previously admitted to the trap and are collected in a small region at the center of the trap. We have demonstrated our capability to capture up to 1~million antiprotons from LEAR in a single shot, electron cool these antiprotons, and transfer up to 95\\% of them into the inner, harmonic region. A storage time in excess of 1 hour was observed. These results have been obtained with the cryogenic trap vacuum coupled to a room temperature vacuum at about l0$ ^- ^{1} ^0 $ Torr, which is an...

  1. Sub-parts-per-billion determination of nitro-substituted polynuclear aromatic hydrocarbons in airborne particulate matter and soil by electron capture-Tandem mass spectrometry.

    Science.gov (United States)

    Vincenti, M; Minero, C; Pelizzetti, E; Fontana, M; De Maria, R

    1996-12-01

    A procedure for the determination of nitro-substiruted polynuclear aromatic hydrocarbons (nitro-PAH) on crude air-particulate and soil extracts is introduced. Elimination of purification and fractionation procedures was made possible by the use of both a selective ionization method, such as electron-capture chemical ionization, and a specific fragmentation process, in an experiment of tandem mass spectrometry (gas chromatography-electron capture tandem mass spectrometry). Different mass spectrometric procedures were compared. The best performance was observed when the nitro-PAH molecular ions [M](-) were mass-selected by the first analyzer under multiple reaction monitoring conditions and then fragmented to NO 2 (-) (m/z 46). Detection limits were on the order of hundreds of femtograms, as determined in extracts of real environmental samples. This corresponds approximately to 5-15 pg of nitro-PAH per cubic meter of air sampled. Calibration curves were linear over 3 orders of magnitude. Applications to contamination from motor vehicle combustion and the iron industry are briefly discussed.

  2. Capturing every patron interaction: the move from paper statistics to an electronic system to track the whole library.

    Science.gov (United States)

    Vardell, Emily; Loper, Kimberly; Vaidhyanathan, Vedana

    2012-01-01

    Reference departments track patron interactions to illustrate the type and number of services provided as well as to tailor librarians' time and expertise to the interest and needs of their patrons. Until 2010 the Reference, Education, and Community Engagement Department at the Calder Memorial Library tracked statistics using a complicated system of paper tic sheets and two Excel™ spreadsheets. After considering different electronic systems, the department decided to employ an electronic form created with SurveyMonkey™ to track patron interactions. After the system had been in place for three months, the authors administered a satisfaction and use survey to collect faculty and staff feedback on the new system. Seven months later the authors undertook usability testing to collect further evaluative data on the electronic form. The patron interaction form continues to be used to collect statistics, provide data for annual reviews, and recognize the contributions of all faculty and staff at the library.

  3. Neutron-capture rates for explosive nucleosynthesis: the case of 68 Ni( n , γ ) 69 Ni

    Energy Technology Data Exchange (ETDEWEB)

    Spyrou, A.; Larsen, A. C.; Liddick, S. N.; Naqvi, F.; Crider, B. P.; Dombos, A. C.; Guttormsen, M.; Bleuel, D. L.; Couture, A.; Campo, L. Crespo; Lewis, R.; Mosby, S.; Mumpower, M. R.; Perdikakis, G.; Prokop, C. J.; Quinn, S. J.; Renstrøm, T.; Siem, S.; Surman, R.

    2017-02-22

    Neutron-capture reactions play an important role in heavy element nucleosynthesis, since they are the driving force for the two processes that create the vast majority of the heavy elements. When a neutron capture occurs on a short-lived nucleus, it is extremely challenging to study the reaction directly and therefore the use of indirect techniques is essential. The present work reports on such an indirect measurement that provides strong constraints on the 68Ni(n, γ)69Ni reaction rate. This is done by populating the compound nucleus 69Ni via the β decay of 69Co and measuring the γ-ray deexcitation of excited states in 69Ni. The β-Oslo method was used to extract the γ-ray strength function and the nuclear level density. In addition the half-life of 69Co was extracted and found to be in agreement with previous literature values. Before the present results, the 68Ni(n, γ)69Ni reaction was unconstrained and the purely theoretical reaction rate was highly uncertain. The new uncertainty on the reaction rate based on the present experiment (variation between upper and lower limit) is approximately a factor of 3. The commonly used reaction libraries JINA-REACLIB and BRUSLIB are in relatively good agreement with the experimental rate. The impact of the new rate on weak r-process calculations is discussed.

  4. Energy levels, radiative rates and electron impact excitation rates for transitions in Al X

    CERN Document Server

    Aggarwal, K M

    2013-01-01

    Energy levels, radiative rates and lifetimes are calculated among the lowest 98 levels of the n <= 4 configurations of Be-like Al X. The GRASP (General-purpose Relativistic Atomic Structure Package) is adopted and data are provided for all E1, E2, M1 and M2 transitions. Similar data are also obtained with the Flexible Atomic Code (FAC) to assess the accuracy of the calculations. Based on comparisons between calculations with the two codes as well as with available measurements, our listed energy levels are assessed to be accurate to better than 0.3%. However, the accuracy for radiative rates and lifetimes is estimated to be about 20%. Collision strengths are also calculated for which the Dirac Atomic R-matrix Code (DARC) is used. A wide energy range (up to 380 Ryd) is considered and resonances resolved in a fine energy mesh in the thresholds region. The collision strengths are subsequently averaged over a Maxwellian velocity distribution to determine effective collision strengths up to a temperature of 1.6...

  5. High Repetition Rate Electron Beam RF-Acceleration and Sub-Millimeter Wave Generation Via a Free Electron Laser.

    Science.gov (United States)

    1986-02-14

    Period, Including Journal References: (a) D.B. McDermott, W.J. Nunan and N.C. Luhmann, Jr., "A High Duty Cycle, Compact 94 GHz Free Electron Laser...34 submitted to Journal IR and am-Waves. (b) W.J. Nunan , D.B. McDermott and N.C. Luhmann, Jr., "A High Repetition *Rate, Compact 94 GHz Free Electron Laser...34 Bulletin of the American Phy- * ) sical Society 30, 1543 (1985). L J (c) D.B. McDermott, W.J. Nunan and N.C. Luhmann, Jr., "A High RepetitionLL

  6. Impact of neutrino flavor oscillations on the neutrino-driven wind nucleosynthesis of an electron-capture supernova

    NARCIS (Netherlands)

    E. Pllumbi; I. Tamborra; S. Wanajo; H.-T. Janka; L. Hüdepohl

    2015-01-01

    Neutrino oscillations, especially to light sterile states, can affect nucleosynthesis yields because of their possible feedback effect on the electron fraction (Ye). For the first time, we perform nucleosynthesis calculations for neutrino-driven wind trajectories from the neutrino-cooling phase of a

  7. Electron capture and deprotonation processes observed in collisions between Xe8+ and multiply protonated cytochrome-C

    NARCIS (Netherlands)

    Martin, S.; Ortega, C.; Chen, L.; Bredy, R.; Vernier, A.; Dugourd, P.; Antoine, R.; Bernard, J.; Reitsma, G.; Gonzalez Magana, Olmo; Hoekstra, Ronnie; Schlathölter, Thomas

    2014-01-01

    Electron-transfer processes in interaction between highly charged ions and multiply protonated proteins have been studied. Collisions between Xe8+ at 96 keV and protonated cytochrome-C at selected charge state (q from 15+ to 19+) result inmass spectra composed mainly of intact molecular ions. From t

  8. [Electron transfer between globular proteins. Dependence of the rate of transfer on distance].

    Science.gov (United States)

    Lakhno, V D; Chuev, G N; Ustinin, M N; Komarov, V M

    1998-01-01

    Based on the assumption that electron transfer between globular proteins occurs by a collective excitation of polaron type, the dependence of the rate of this process on the distance between the donor and acceptor centers with regard to their detailed electron structure was calculated. The electron structure of the heme was calculated by the quantum-chemical MNDO-PM3 method. The results were compared with experimental data on interprotein and intraglobular electron transfer. It is shown that, in the framework of this model, the electron transfer is not exponential and does not require a particular transfer pathway since the whole protein macromolecule is involved in the formation of the electron excited state.

  9. Large electron transfer rate effects from the Duschinsky mixing of vibrations

    DEFF Research Database (Denmark)

    Sando, Gerald M.; Spears, Kenneth G; Hupp, Joseph T

    2001-01-01

    We systematically test how the Duschinsky mixing of normal coordinate vibrations affects transition rates for electron transfer (ET). We find that ET rates in the inverted region can increase many orders of magnitude from Duschinsky mixing, and both totally symmetric and nontotally symmetric...... of magnitude for inverted electron transfer reactions and modest mixing. The peak location in a rate vs energy gap plot can depend on the degree of Duschinsky mixing, and therefore it corresponds to a sum of solvent and an effective vibrational reorganization energy that is not predictable by simple models...... vibrations are very important. The Duschinsky effect arises when two electronic states have vibrational normal mode coordinate systems that are rotated and translated relative to each other. We use a conventional quantum rate model for ET, and the examples include 6-8 vibrations, where two vibrational modes...

  10. Electron-impact vibrational excitation rates in the flow field of aeroassisted orbital transfer vehicles

    Science.gov (United States)

    Lee, J.-H.

    1985-01-01

    This paper examines the vibrational excitation rate processes expected in the flow field of aeroassisted orbital transfer vehicles (AOTVs). An analysis of the multiple-quantum vibrational excitation processes by electron impact is made to predict the vibrational excitation cross sections, rate coefficients, and relaxation times which control vibrational temperature. The expression for the rate of electron-vibration energy transfer is derived by solving the system of master equations which account for the multiple-level transitions. The vibrational excitation coefficients, which are the prerequisite physical quantities in solving the obtained vibrational equation, are calculated based on the theoretically predicted cross sections. These cross sections are obtained from quantum mechanical calculations, based on the concept that vibrational excitation of molecules by electron impact occurs through formation of an intermediate negative ion state. Finally, the modified Landau-Teller-type rate equation, which is suitable for the numerical calculations for the AOTV flow fields, is suggested.

  11. Energy levels, radiative rates and electron impact excitation rates for transitions in C III

    CERN Document Server

    Aggarwal, K M

    2015-01-01

    We report energy levels, radiative rates (A-values) and lifetimes for the astrophysically-important Be-like ion C III. For the calculations, 166 levels belonging to the $n \\le$ 5 configurations are considered and the {\\sc grasp} (General-purpose Relativistic Atomic Structure Package) is adopted. Einstein A-coefficients are provided for all E1, E2, M1 and M2 transitions, while lifetimes are compared with available measurements as well as theoretical results, and no large discrepancies noted. Our energy levels are assessed to be accurate to better than 1\\% for a majority of levels, and A-values to better than 20\\% for most transitions. Collision strengths are also calculated, for which the Dirac Atomic R-matrix Code ({\\sc darc}) is used. A wide energy range, up to 21 Ryd, is considered and resonances resolved in a fine energy mesh in the thresholds region. The collision strengths are subsequently averaged over a Maxwellian velocity distribution to determine effective collision strengths up to a temperature of 8...

  12. Energy levels, radiative rates and electron impact excitation rates for transitions in Si III

    CERN Document Server

    Aggarwal, K M

    2016-01-01

    Energy levels and radiative rates (A-values) for four types of transitions (E1, E2, M1, and M2) are reported for an astrophysically important Mg-like ion Si~III, whose emission lines have been observed in a variety of plasmas. For the calculations, well-known and widely-used GRASP code has been adopted, and results are listed for transitions among the 141 levels of the 3$\\ell3\\ell'$ and 3$\\ell$4$\\ell$ configurations. Experimental energies are available for only the lowest 58 levels but there is no major discrepancy with theoretical results. Similarly, the A-values and lifetimes show a satisfactory agreement with other available results, particularly for strong E1 transitions. Collision strengths are also calculated, with the DARC code, and listed for resonance transitions over a wide energy range, up to 30~Ryd. No similar results are available in the literature for comparisons. However, comparisons are made with the more important parameter, effective collision strength ($\\Upsilon$), for which recent $R$-matr...

  13. THE FINAL FATE OF STARS THAT IGNITE NEON AND OXYGEN OFF-CENTER: ELECTRON CAPTURE OR IRON CORE-COLLAPSE SUPERNOVA?

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Samuel [Department of Physics and Astronomy, University of Victoria, BC V8W 3P6 (Canada); Hirschi, Raphael [Astrophysics Group, Lennard-Jones Building, Keele University, Staffordshire ST5 5BG (United Kingdom); Nomoto, Ken' ichi, E-mail: swjones@uvic.ca [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

    2014-12-20

    In the ONeMg cores of 8.8-9.5 M {sub ☉} stars, neon and oxygen burning is ignited off-center. Whether or not the neon-oxygen flame propagates to the center is critical for determining whether these stars undergo Fe core collapse or electron-capture-induced ONeMg core collapse. We present more details of stars that ignite neon and oxygen burning off-center. The neon flame is established in a manner similar to the carbon flame of super-AGB stars, albeit with a narrower flame width. The criteria for establishing a flame can be met if the strict Schwarzschild criterion for convective instability is adopted. Mixing across the interface of the convective shell disrupts the conditions for the propagation of the burning front, and instead the shell burns as a series of inward-moving flashes. While this may not directly affect whether or not the burning will reach the center (as in super-AGB stars), the core is allowed to contract between each shell flash. Reduction of the electron fraction in the shell reduces the Chandrasekhar mass and the center reaches the threshold density for the URCA process to activate and steer the remaining evolution of the core. This highlights the importance of a more accurate treatment of mixing in the stellar interior for yet another important question in stellar astrophysics—determining the properties of stellar evolution and supernova progenitors at the boundary between electron capture supernova and iron core-collapse supernova.

  14. Electronic capture and communication of synoptic cancer data elements from pathology reports: results of the Reporting Pathology Protocols 2 (RPP2) project.

    Science.gov (United States)

    Hassell, Lewis; Aldinger, Wendy; Moody, Cheryl; Winters, Sharon; Gerlach, Ken; Schwenn, Molly; Perriello, Deborah

    2009-01-01

    Pathology reports represent a rich data source for cancer registries. The College of American Pathologists (CAP) Cancer Checklists present pathology reports in synoptic form and allow registries to be updated electronically. To assess the challenge of employing the CAP Cancer Checklists in pathology laboratories and transmitting that information to cancer registries, we conducted a pilot project: the Reporting Pathology Protocols project (RPP2). The RPP2 project was a multi-year, "proof of concept" demonstration that assessed pathology report-generated data for 3 CAP Cancer Checklists (breast, prostate, and melanoma) in several different cancer registry-pathology laboratory combinations in 3 states. Collaborating pathology laboratories and state cancer registries in California, Maine, and Pennsylvania identified key questions (queries) to address in the course of the project, developed and tested standardized HL7 messaging specifications to link senders and recipients, and then assessed the actual process results using either parallel reporting or retrospective-prospective cases for each tumor type. Successful electronic transfer and capture of pertinent data elements for numerous examples of each tumor type was accomplished in each participating cancer registry/reporting laboratory/information system combination. We noted shortcomings in the electronically encoded CAP Checklists as opposed to text-based reports, particularly for breast cancers. We uncovered opportunities to improve Checklists and the information systems that incorporate them. Workflow, productivity, and timeliness of reporting are areas where electronically encoded reports may enhance cancer registry processes. The accuracy and completeness of electronically encoded data appears largely comparable to text-based data, but subject to the degree of synchrony between the formats of text-based and electronic reports.

  15. Real Time Quantification of Ultrafast Photoinduced Bimolecular Electron Transfer Rate: Direct Probing of the Transient Intermediate.

    Science.gov (United States)

    Mukherjee, Puspal; Biswas, Somnath; Sen, Pratik

    2015-08-27

    Fluorescence quenching studies through steady-state and time-resolved measurements are inadequate to quantify the bimolecular electron transfer rate in bulk homogeneous solution due to constraints from diffusion. To nullify the effect of diffusion, direct evaluation of the rate of formation of a transient intermediate produced upon the electron transfer is essential. Methyl viologen, a well-known electron acceptor, produces a radical cation after accepting an electron, which has a characteristic strong and broad absorption band centered at 600 nm. Hence it is a good choice to evaluate the rate of photoinduced electron transfer reaction employing femtosecond broadband transient absorption spectroscopy. The time constant of the aforementioned process between pyrene and methyl viologen in methanol has been estimated to be 2.5 ± 0.4 ps using the same technique. The time constant for the backward reaction was found to be 14 ± 1 ps. These values did not change with variation of concentration of quencher, i.e., methyl viologen. Hence, we can infer that diffusion has no contribution in the estimation of rate constants. However, on changing the solvent from methanol to ethanol, the time constant of the electron transfer reaction has been found to increase and has accounted for the change in solvent reorganization energy.

  16. Growth rates and age at adult size of loggerhead sea turtles (Caretta caretta in the Mediterranean Sea, estimated through capture-mark-recapture records

    Directory of Open Access Journals (Sweden)

    Paolo Casale

    2009-09-01

    Full Text Available Growth rates of the juvenile phase of loggerhead turtles (Caretta caretta were estimated for the first time in the Mediterranean Sea from capture-mark-recapture records. Thirty-eight turtles were released from Italian coasts and re-encountered after 1.0-10.9 years in the period 1986-2007. Their mean CCL (curved carapace length ranged from 32.5 to 82.0 cm and they showed variable growth rates, ranging from 0 to 5.97 cm/yr (mean: 2.5. The association between annual growth rate and three covariates (mean year, mean size and time interval was investigated through a non-parametric modelling approach. Only mean size showed a clear effect on growth rate, described by a monotonic declining curve. Variability indicates that factors not included in the model, probably individual-related ones, have an important effect on growth rates. Based on the monotonic decreasing growth function which indicates no growth spurt, a von Bertalanffy growth function was used to estimate the time required by turtles to grow within the observed size range. The results indicate that turtles would take 16-28 years to reach 66.5-84.7 cm CCL, the average nesting female sizes observed at the most important Mediterranean nesting sites, which can be considered an approximation of the size at maturity.

  17. Marine turtle capture data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To estimate abundance, growth, and survival rate and to collect tissue samples, marine turtles are captured at nesting beaches and foraging grounds through various...

  18. Capture reactions

    NARCIS (Netherlands)

    Endt, P.M.

    1956-01-01

    Capture reactions will be considered here from the viewpoint of the nuclear spectroscopist. Especially important to him are the capture of neutrons, protons, and alpha particles, which may proceed through narrow resonances, offering a well defined initial state for the subsequent deexcitation proces

  19. On collisional capture rates of irregular satellites around the gas-giant planets and the minimum mass of the solar nebula

    Science.gov (United States)

    Koch, F. Elliott; Hansen, Bradley M. S.

    2011-09-01

    We investigate the probability that an inelastic collision of planetesimals within the Hill sphere of the Jovian planets could explain the presence and orbits of observed irregular satellites. Capture of satellites via this mechanism is highly dependent on not only the mass of the protoplanetary disc, but also the shape of the planetesimal size distribution. We performed 2000 simulations for integrated time intervals ˜2 Myr and found that, given the currently accepted value for the minimum mass solar nebula and planetesimal number density based upon the Nesvorný et al. and Charnoz & Morbidelli size distribution dN˜D-3.5dD, the collision rates for the different Jovian planets range between ˜0.6 and ≳170 Myr-1 for objects with radii 1 km ≤r≤ 10 km. Additionally, we found that the probability that these collisions remove enough orbital energy to yield a bound orbit was ≲10-5 and had very little dependence on the relative size of the planetesimals. Of these collisions, the collision energy between two objects was ≳103 times the gravitational binding energy for objects with radii ˜100 km. We find that capturing irregular satellites via collisions between unbound objects can only account for ˜0.1 per cent of the observed population, hence this cannot be the sole method of producing irregular satellites.

  20. TrapTech R-Octenol Lure Does Not Improve the Capture Rates of Aedes albopictus (Diptera: Culicidae) and Other Container-Inhabiting Species in Biogents Sentinel Traps.

    Science.gov (United States)

    Unlu, Isik; Faraji, Ary; Indelicato, Nicholas; Rochlin, Ilia

    2016-07-01

    Aedes albopictus (Skuse) and other container-inhabiting species have become important public health concerns due to the transmission of dengue, chikungunya, and Zika viruses. Effective surveillance is dependent on the ability to collect a sufficient number of mosquitoes for population monitoring and pathogen isolation. The Biogents Sentinel (BGS) trap supplied with a proprietary human skin lure has become the standard tool for container-inhabiting Aedes species collections worldwide. Recently, R-octenol, a single isomer of the well characterized mosquito attractant octenol, was shown to greatly improve the capture rate of some Aedes species when utilized with the Center for Disease Control and Prevention (CDC) light traps and Mosquito Magnet traps. This study evaluated the effectiveness of the TrapTech lure (TT lure), containing R-octenol, alone or in combination with the human skin lure in a BGS trap to capture Ae. albopictus and other species. BGS traps with human skin lures or a combination of the two lures collected approximately twice as many Ae. albopictus females compared to those with TT lures. Unlike previous studies, baiting BGS traps with TT lures did not result in increased diversity of mosquito species, or in higher numbers of other container-inhabiting Aedes species. Although human skin lures were clearly superior to TT R-octenol lures in BGS traps, R-octenol lures are more widely available and might still be used as an alternative lure, especially when Ae. albopictus populations are high.

  1. The Nuclear Structure and Associated Electron Capture Rates on Odd-Z Nucleus $^{51}$V in Stellar Matter

    CERN Document Server

    Rahman, Muneeb-Ur

    2014-01-01

    The Gamow-Teller strength distribution function, B(GT), for the odd Z parent $^{51}$V, $N-Z$ =5, up to 30 MeV of excitation energy in the daughter $^{51}$Ti is calculated in the domain of proton-neutron Quasiparticle Random Phase Approximation (pn-QRPA) theory. The pn-QRPA results are compared against other theoretical calculations, (n, p) and high resolution (d, $^{2}$He) reaction experiments. For the case of (d, $^{2}$He) reaction the calibration was performed for $0\\leq E_{j} \\leq 5.0$ MeV, where the authors stressed that within this excitation energy range the $\\Delta L = 0$ transition strength can be extracted with high accuracy for $^{51}$V. Within this energy range the current pn-QRPA total B(GT) strength 0.75 is in good agreement with the (d, $^{2}$He) experiment's total strength of 0.9 $\\pm$ 0.1. The pn-QRPA calculated Gamow-Teller centroid at 4.20 MeV in daughter $^{51}$Ti is also in good agreement with high resolution (d, $^{2}$He) experiment which placed the Gamow-Teller centroid at 4.1 $\\pm$ 0.4 ...

  2. Increased ratio of electron transport to net assimilation rate supports elevated isoprenoid emission rate in eucalypts under drought.

    Science.gov (United States)

    Dani, Kaidala Ganesha Srikanta; Jamie, Ian McLeod; Prentice, Iain Colin; Atwell, Brian James

    2014-10-01

    Plants undergoing heat and low-CO2 stresses emit large amounts of volatile isoprenoids compared with those in stress-free conditions. One hypothesis posits that the balance between reducing power availability and its use in carbon assimilation determines constitutive isoprenoid emission rates in plants and potentially even their maximum emission capacity under brief periods of stress. To test this, we used abiotic stresses to manipulate the availability of reducing power. Specifically, we examined the effects of mild to severe drought on photosynthetic electron transport rate (ETR) and net carbon assimilation rate (NAR) and the relationship between estimated energy pools and constitutive volatile isoprenoid emission rates in two species of eucalypts: Eucalyptus occidentalis (drought tolerant) and Eucalyptus camaldulensis (drought sensitive). Isoprenoid emission rates were insensitive to mild drought, and the rates increased when the decline in NAR reached a certain species-specific threshold. ETR was sustained under drought and the ETR-NAR ratio increased, driving constitutive isoprenoid emission until severe drought caused carbon limitation of the methylerythritol phosphate pathway. The estimated residual reducing power unused for carbon assimilation, based on the energetic status model, significantly correlated with constitutive isoprenoid emission rates across gradients of drought (r(2) > 0.8) and photorespiratory stress (r(2) > 0.9). Carbon availability could critically limit emission rates under severe drought and photorespiratory stresses. Under most instances of moderate abiotic stress levels, increased isoprenoid emission rates compete with photorespiration for the residual reducing power not invested in carbon assimilation. A similar mechanism also explains the individual positive effects of low-CO2, heat, and drought stresses on isoprenoid emission.

  3. Dose-rate conversion factors for external exposure to photons and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Kocher, D.C.

    1981-08-01

    Dose-rate conversion factors for external exposure to photons and electrons have been calculated for approximately 500 radionuclides of potential importance in environmental radiological assessments. The dose-rate factors were obtained using the DOSFACTER computer code. The results given in this report incorporate calculation of electron dose-rate factors for radiosensitive tissues of the skin, improved estimates of organ dose-rate factors for photons, based on organ doses for monoenergetic sources at the body surface of an exposed individual, and the spectra of scattered photons in air from monoenergetic sources in an infinite, uniformly contaminated atmospheric cloud, calculation of dose-rate factors for other radionuclides in addition to those of interest in the nuclear fuel cycle, and incorporation of updated radioactive decay data for all radionuclides. Dose-rate factors are calculated for three exposure modes - immersion in contaminated air, immersion in contaminated water, and exposure at a height of 1 m above a contaminated ground surface. The report presents the equations used to calculate the external dose-rate factors for photons and electrons, documentation of the revised DOSFACTER computer code, and a complete tabulation of the calculated dose-rate factors. 30 refs., 12 figs.

  4. Difference of Electron Capture and Transfer Dissociation Mass Spectrometry on Ni2+-, Cu2+-, and Zn2+-Polyhistidine Complexes in the Absence of Remote Protons

    Science.gov (United States)

    Asakawa, Daiki; De Pauw, Edwin

    2016-07-01

    Electron capture dissociation (ECD) and electron transfer dissociation (ETD) in metal-peptide complexes are dependent on the metal cation in the complex. The divalent transition metals Ni2+, Cu2+, and Zn2+ were used as charge carriers to produce metal-polyhistidine complexes in the absence of remote protons, since these metal cations strongly bind to neutral histidine residues in peptides. In the case of the ECD and ETD of Cu2+-polyhistidine complexes, the metal cation in the complex was reduced and the recombination energy was redistributed throughout the peptide to lead a zwitterionic peptide form having a protonated histidine residue and a deprotonated amide nitrogen. The zwitterion then underwent peptide bond cleavage, producing a and b fragment ions. In contrast, ECD and ETD induced different fragmentation processes in Zn2+-polyhistidine complexes. Although the N-Cα bond in the Zn2+-polyhistidine complex was cleaved by ETD, ECD of Zn2+-polyhistidine induced peptide bond cleavage accompanied with hydrogen atom release. The different fragmentation modes by ECD and ETD originated from the different electronic states of the charge-reduced complexes resulting from these processes. The details of the fragmentation processes were investigated by density functional theory.

  5. Effect of structural parameters on the electron capture dissociation and collision-induced dissociation pathways of copper(II)-peptide complexes.

    Science.gov (United States)

    Chen, Xiangfeng; Wang, Ze; Li, Wan; Wong, Y L Elaine; Chan, T-W Dominic

    2015-01-01

    The gas-phase dissociation pathways of proteins/peptides are usually affected by the nature of the charge carrier and the sequence of amino acid residues. The effects of peptide structural parameters, including peptide composition, chain length and amide hydrogen, on the gas-phase dissociation of Cu(II)-model peptide complexes were explored in this study. Polyglycine peptides with flexible frames were used as probes to reduce the complexity of the system and illustrate the mechanism. Results revealed that the types of fragment ions generated in the electron capture dissociation (ECD) of Cu(II)-adducted peptides changed according to the basic amino acid residue composition. Charged or neutral tryptophan side-chain losses were observed in the collision-induced dissociation (CID) of Cu(II)-peptide complexes. Internal electron transfer between tryptophan and metal ion within the complex occurred during the CID reaction, leaving the charge-reduced Cu(+) as a closed d-shell stable electron configuration. The choice of the reaction channel was then determined by the gas-phase basicity of the peptide. Amide hydrogen was critical in the formation of metalated b-/y-ions in the ECD process as determined through mutation of the backbone amide group. Increasing the chain length suppressed the ECD of Cu-metalated peptide species. Our results indicate that the structural parameters of peptides play important roles in the gas-phase dissociation processes of Cu-peptide complexes.

  6. Nanosolvation by acetonitrile and 18-crown-6 ether induce strongly different effects on the electron-capture induced dissociation of aromatic tripeptide cations in the gas phase

    DEFF Research Database (Denmark)

    MacLot, S.; Rangama, J.; Nielsen, Steen Brøndsted;

    2013-01-01

    , acetonitrile and 18-crown-6 ether (CE), to these tripeptide cations on the relative probabilities of their main fragmentation channels (H loss, NH3 loss and N — Cα bond cleavage) after electron capture from sodium atoms. First, we recorded the spectra of bare peptide ions, and found that N — Cα bond cleavage......-terminal ammonium group. Besides, this experimental result is consistent with our DFT calculations, which suggest a lower abundance of N terminally-protonated [KWK+2H]2+(CE)2 compared to bare tripeptide cations. Extracting the H-loss contribution from ECID data had never been done for tripeptides nanosolvated by CE....... This allowed us to observe the enhancement of H loss from KWK and KYK nanosolvated by two CE, but surprisingly, not by one. This peculiar behavior might be due to H transfer from the reduced radical NH3 group to CE, followed by loss of the [CE+H] radical....

  7. Simultaneous determination of florfenicol and florfenicol amine in fish, shrimp, and swine muscle by gas chromatography with a microcell electron capture detector.

    Science.gov (United States)

    Zhang, Suxia; Sun, Fengyun; Li, Jiancheng; Cheng, Linli; Shen, Jianzhong

    2006-01-01

    A rapid and sensitive gas chromatography method was developed for the simultaneous determination of florfenicol (FF) and its metabolite florfenicol amine (FFA) in fish, shrimp, and swine muscle. The extracted samples were defatted with hexane and cleaned up by solid-phase extraction using Oasis MCX cartridges. The eluate was evaporated to dryness, and residues were derivatized and determined by gas chromatography with a microcell electron capture detector. Overall average recoveries ranged from 81.7 to 109.7% for fish, 94.1 to 103.4% for shrimp, and 71.5 to 91.4% for swine muscle. The detection limit was 0.5 ng/g for FF and 1 ng/g for FFA, respectively. The method was validated for the determination of incurred swine muscle samples in an actual residue study.

  8. Measurement of the double K-shell vacancy creation probability in the electron-capture decay of 55Fe with active-pixel detectors

    Science.gov (United States)

    Michel, Thilo; Bergmann, Benedikt; Durst, Jürgen; Filipenko, Mykaylo; Gleixner, Thomas; Zuber, Kai

    2014-01-01

    Background: In electron-capture decay, a second K-shell vacancy is eventually created with a small probability. Measurements of the double-vacancy creation probability per K-shell electron capture PKK of various nuclei undergoing electron-capture decays have already been performed, but the statistical accuracy of PKK of several nuclides is still not satisfying. Purpose: The purpose of this experiment was to improve the statistical error of PKK in the decay of 55Fe and to demonstrate the possibility of detecting double-vacancy creation events with position resolving pixel detectors. This enables angle resolved measurements. Method: For the first time, two active-pixel detectors (A,B) were used to detect satellite- and hypersatellite-line photons in coincidence either both in two clusters of triggered pixels in only one detector (A,B) or in both detectors (A∧B). PKK was determined for the two detectors regarded as one single, larger detector (PKK), for each detector separately (single-sided analysis: PKK ,A⊻B), and for both detectors in coincidence (double-sided analysis: PKK ,A∧B). Results: The result of the experiment is PKK=(1.531±0.079)×10-4 with a systematic error of (ΔPKK)syst=±0.023×10-4. This value is in agreement with the value previously measured by Campbell et al. of PKK=(1.3±0.2)×10-4. The discrepancy in literature between PKK of 54Mn to the expected value extrapolated from 55Fe almost vanished with our result. The asymmetry between the result of the single-sided analysis (PKK ,A⊻B) and the double-sided analysis (PKK ,A∧B) is consistent with zero: (PKK ,A⊻B-PKK ,A∧B)/(PKK ,A⊻B+PKK ,A∧B)=-0.003±0.051. This supports the assumption that angular correlations between the two photons are negligible within the achieved level of statistical accuracy for the given angular acceptance of our detectors. Conclusions: One can conclude that hybrid photon counting pixel detectors can be used to measure angular correlations between the directions

  9. Interference effect of electron-capture X-rays from an {sup 125}I-labeled protein monolayer in an aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Y.C.; Suzuki, Yoshio; Ishibashi, Tadashi [Hitachi Ltd., Hatoyama, Saitama (Japan). Advanced Research Lab.; Satoh, Isamu

    1995-06-01

    We have measured the vertical distribution of a radioactively labeled protein in an aqueous solution by using the interference effect of electron-capture X-rays from radioisotopes. This interference is between the direct monochromatic emission from radioactive atoms and the emission totally reflected by the substrate surface. Structural information about radioactive atoms can be obtained by analyzing the measured interference fringes, since the period of these fringes depends on the position of the radioactive atoms relative to the substrate surface. In this work we used bovine serum albumin radioiodinated with carrier free {sup 125}I by using Chloramine T. The protein molecules were electrostatically adsorbed in a monolayer form by the positively charged Langmuir layer at the air-water interface. (author).

  10. Screening of priority pesticides in Ulva sp. seaweeds by selective pressurized solvent extraction before gas chromatography with electron capture detector analysis.

    Science.gov (United States)

    Pinto, M I; Micaelo, C; Vale, C; Sontag, G; Noronha, J P

    2014-11-01

    This work reports a fast and reliable analytical method for the screening of priority pesticides (PPs) in Ulva sp. seaweeds by gas chromatography with electron capture detection. Extraction and sample clean-up were performed in one single step by selective pressurized liquid extraction (SPLE). Several parameters affecting SPLE performance were optimized. Method performance was compared with standard Soxhlet extraction. Significant decrease of the time of analysis with better recoveries for a greater number of PPs was achieved by SPLE. Average recoveries ranged from 71 to 103% with RSD < 10%. Field application showed the presence of PP in the range of 3-11 ng g(-1) in seaweeds collected in a coastal lagoon after a long period of heavy rains. These results suggest that Ulva sp. seaweeds tend to accumulate PPs and have the potential to be used as early alert signals of aquatic pollution especially after rains and storm events.

  11. Velocity effect in the l-distribution of the electron capture in collisions of highly charged Ar{sup 8+} ions with a Li(2s) target

    Energy Technology Data Exchange (ETDEWEB)

    Pascale, J. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Recherche sur l`Etat Condense, les Atomes et les Molecules; Jacquet, E.; Boduch, P.; Chantepie, M.; Lecler, D. [Caen Univ., 14 (France). Lab. de Spectroscopie Atomique

    1994-12-31

    The effect of the velocity of the incident ions in the l-distributions of the electron capture in collisions of highly charged Ar{sup 8+} ions with a Li(2s) target is studied. These Ar{sup 8+} - Li(2s) collisions are experimentally studied by means of near UV and visible photon spectroscopy (200-600 nm) and theoretically analysed by means of three-body classical trajectory Monte-Carlo method. In addition to the effect of the projectile core, we show that the final nl-distributions are, for the most populated n = 8 and n = 9 states strongly energy dependent. (authors). 11 refs., 3 figs., 2 tabs.

  12. Moulting of insect tracheae captured by light and electron-microscopy in the metathoracic femur of a third instar locust Locusta migratoria.

    Science.gov (United States)

    Snelling, Edward P; Seymour, Roger S; Runciman, Sue

    2011-09-01

    The insect tracheal system is an air-filled branching network of internal tubing that functions to exchange respiratory gases between the tissues and the environment. The light and electron-micrographs presented in this study show tracheae in the process of moulting, captured from the metathoracic hopping femur of a juvenile third instar locust (Locusta migratoria). The images provide evidence for the detachment of the cuticular intima from the tracheal epithelial cells, the presence of moulting fluid between the new and old cuticle layers, and the withdrawal of the shed cuticular lining through larger upstream regions of the tracheal system during moulting. The micrographs also reveal that the cuticular intima of the fine terminal branches of the tracheal system is cast at ecdysis. Therefore, the hypothesis that tracheoles retain their cuticle lining at each moult may not apply to all insect species or developmental stages.

  13. Solving the Boltzmann equation to obtain electron transport coefficients and rate coefficients for fluid models

    Energy Technology Data Exchange (ETDEWEB)

    Hagelaar, G J M; Pitchford, L C [Centre de Physique des Plasmas et de leurs Applications de Toulouse, Universite Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 9 (France)

    2005-11-15

    Fluid models of gas discharges require the input of transport coefficients and rate coefficients that depend on the electron energy distribution function. Such coefficients are usually calculated from collision cross-section data by solving the electron Boltzmann equation (BE). In this paper we present a new user-friendly BE solver developed especially for this purpose, freely available under the name BOLSIG+, which is more general and easier to use than most other BE solvers available. The solver provides steady-state solutions of the BE for electrons in a uniform electric field, using the classical two-term expansion, and is able to account for different growth models, quasi-stationary and oscillating fields, electron-neutral collisions and electron-electron collisions. We show that for the approximations we use, the BE takes the form of a convection-diffusion continuity-equation with a non-local source term in energy space. To solve this equation we use an exponential scheme commonly used for convection-diffusion problems. The calculated electron transport coefficients and rate coefficients are defined so as to ensure maximum consistency with the fluid equations. We discuss how these coefficients are best used in fluid models and illustrate the influence of some essential parameters and approximations.

  14. Gas-phase doubly charged complexes of cyclic peptides with copper in +1, +2 and +3 formal oxidation states: formation, structures and electron capture dissociation.

    Science.gov (United States)

    Afonso, Carlos; Tabet, Jean-Claude; Giorgi, Gianluca; Tureček, František

    2012-02-01

    Copper complexes with a cyclic D-His-β-Ala-L-His-L-Lys and all-L-His-β-Ala-His-Lys peptides were generated by electrospray which were doubly charged ions that had different formal oxidation states of Cu(I), Cu(II) and Cu(III) and different protonation states of the peptide ligands. Electron capture dissociation showed no substantial differences between the D-His and L-His complexes. All complexes underwent peptide cross-ring cleavages upon electron capture. The modes of ring cleavage depended on the formal oxidation state of the Cu ion and peptide protonation. Density functional theory (DFT) calculations, using the B3LYP with an effective core potential at Cu and M06-2X functionals, identified several precursor ion structures in which the Cu ion was threecoordinated to pentacoordinated by the His and Lys side-chain groups and the peptide amide or enolimine groups. The electronic structure of the formally Cu(III) complexes pointed to an effective Cu(I) oxidation state with the other charge residing in the peptide ligand. The relative energies of isomeric complexes of the [Cu(c-HAHK + H)](2+) and [Cu(c-HAHK - H)](2+) type with closed electronic shells followed similar orders when treated by the B3LYP and M06-2X functionals. Large differences between relative energies calculated by these methods were obtained for open-shell complexes of the [Cu(c-HAHK)](2+) type. Charge reduction resulted in lowering the coordination numbers for some Cu complexes that depended on the singlet or triplet spin state being formed. For [Cu(c-HAHK - H)](2+) complexes, solution H/D exchange involved only the N-H protons, resulting in the exchange of up to seven protons, as established by ultra-high mass resolution measurements. Contrasting the experiments, DFT calculations found the lowest energy structures for the gas-phase ions that were deprotonated at the peptide C(α) positions.

  15. A Multi-Channel Opto-Electronic Sensor to Accurately Monitor Heart Rate against Motion Artefact during Exercise

    Directory of Open Access Journals (Sweden)

    Abdullah Alzahrani

    2015-10-01

    Full Text Available This study presents the use of a multi-channel opto-electronic sensor (OEPS to effectively monitor critical physiological parameters whilst preventing motion artefact as increasingly demanded by personal healthcare. The aim of this work was to study how to capture the heart rate (HR efficiently through a well-constructed OEPS and a 3-axis accelerometer with wireless communication. A protocol was designed to incorporate sitting, standing, walking, running and cycling. The datasets collected from these activities were processed to elaborate sport physiological effects. t-test, Bland-Altman Agreement (BAA, and correlation to evaluate the performance of the OEPS were used against Polar and Mio-Alpha HR monitors. No differences in the HR were found between OEPS, and either Polar or Mio-Alpha (both p > 0.05; a strong correlation was found between Polar and OEPS (r: 0.96, p < 0.001; the bias of BAA 0.85 bpm, the standard deviation (SD 9.20 bpm, and the limits of agreement (LOA from −17.18 bpm to +18.88 bpm. For the Mio-Alpha and OEPS, a strong correlation was found (r: 0.96, p < 0.001; the bias of BAA 1.63 bpm, SD 8.62 bpm, LOA from −15.27 bpm to +18.58 bpm. These results demonstrate the OEPS to be capable of carrying out real time and remote monitoring of heart rate.

  16. Large electron transfer rate effects from the Duschinsky mixing of vibrations

    DEFF Research Database (Denmark)

    Sando, Gerald M.; Spears, Kenneth G; Hupp, Joseph T

    2001-01-01

    We systematically test how the Duschinsky mixing of normal coordinate vibrations affects transition rates for electron transfer (ET). We find that ET rates in the inverted region can increase many orders of magnitude from Duschinsky mixing, and both totally symmetric and nontotally symmetric...... are mixed with different amounts of coordinate rotation. The multidimensional Franck-Condon factors (FCF) are computed with standard algorithms and recently developed recursion relations. When displaced, totally symmetric modes are involved, rates with Duschinsky mixing can increase several orders...... of magnitude for inverted electron transfer reactions and modest mixing. The peak location in a rate vs energy gap plot can depend on the degree of Duschinsky mixing, and therefore it corresponds to a sum of solvent and an effective vibrational reorganization energy that is not predictable by simple models...

  17. A new method for measurement of the vitrification rate of earthenware texture by scanning electron microscope.

    Science.gov (United States)

    Moon, Eun Jung; Kim, Su Kyeong; Han, Min Su; Lee, Eun Woo; Heo, Jun Su; Lee, Han Hyoung

    2013-08-01

    A new method for determining the vitrification rate of pottery depending on the firing temperature was devised using secondary electron images (SEI) of scanning electron microscope (SEM). Several tests were performed to establish the appropriate operating conditions of SEM and reproducibility as well as to examine the applicability of the method. The grayscale values converted from each pixel of SEI were used to determine the vitrification rate of pottery, which in our study were artificially fired specimens composed of three types of clay. A comparison between the vitrification rate value and appearance temperature of minerals shows that mullite formation starts at 1,100°C, during which the vitrification rate rapidly increases by over 10%. In consequence, the result presented here demonstrates that the new method can be applied to estimate the firing temperature of pottery.

  18. Improved rate control for electron-beam evaporation and evaluation of optical performance improvements.

    Science.gov (United States)

    Gevelber, Michael; Xu, Bing; Smith, Douglas

    2006-03-01

    A new deposition-rate-control and electron-beam-gun (e-gun) strategy was developed that significantly reduces the growth-rate variations for e-beam-deposited SiO2 coatings. The resulting improvements in optical performance are evaluated for multilayer bandpass filters. The adverse effect of uneven silica-source depletion on coating spectral performances during long deposition runs is discussed.

  19. Cross Sections and Rate Coefficients for Vibrational Excitation of HeH+ Molecule by Electron Impact

    Directory of Open Access Journals (Sweden)

    Mehdi Ayouz

    2016-12-01

    Full Text Available Cross sections and thermally-averaged rate coefficients for vibration (de-excitation of HeH + by an electron impact are computed using a theoretical approach that combines the multi-channel quantum defect theory and the UK R-matrix code. Fitting formulas with a few numerical parameters are derived for the obtained rate coefficients. The interval of applicability of the formulas is from 40 to 10,000 K.

  20. Theory and experiment on the cuprous-cupric electron transfer rate at a copper electrode.

    Energy Technology Data Exchange (ETDEWEB)

    Halley, J. W.; Smith, B. B.; Walbran, S.; Curtiss, L. A.; Rigney, R. O.; Sutjianto, A.; Hung, N. C.; Yonco, R. M.; Nagy, Z.; Univ. of Minnesota; NREL

    1999-04-01

    We describe results of experiment and theory of the cuprous-cupric electron transfer rate in an aqueous solution at a copper electrode. The methods are similar to those we reported earlier for the ferrous-ferric rate. The comparison strongly suggests that, in marked distinction to the ferrous-ferric case, the electron transfer reaction is adiabatic. The model shows that the activation barrier is dominated by the energy required for the ion to approach the electrode, rather than by the energy required for rearrangement of the solvation shell, also in sharp distinction to the case of the ferric-ferrous electron transfer at a gold electrode. Calculated activation barriers based on this image agree with the experimental results reported here.

  1. Theory and experiment on the cuprous{endash}cupric electron transfer rate at a copper electrode

    Energy Technology Data Exchange (ETDEWEB)

    Halley, J.W. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Smith, B.B. [National Renewable Energy Laboratory, Golden, Colorado (United States); Walbran, S. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Curtiss, L.A.; Rigney, R.O.; Sutjianto, A.; Hung, N.C.; Yonco, R.M.; Nagy, Z. [Argonne National Laboratory, Divisions of Materials Science, Chemistry and Chemical Technology, Argonne, Illinois 60439-4837 (United States)

    1999-04-01

    We describe results of experiment and theory of the cuprous{endash}cupric electron transfer rate in an aqueous solution at a copper electrode. The methods are similar to those we reported earlier for the ferrous{endash}ferric rate. The comparison strongly suggests that, in marked distinction to the ferrous{endash}ferric case, the electron transfer reaction is adiabatic. The model shows that the activation barrier is dominated by the energy required for the ion to approach the electrode, rather than by the energy required for rearrangement of the solvation shell, also in sharp distinction to the case of the ferric{endash}ferrous electron transfer at a gold electrode. Calculated activation barriers based on this image agree with the experimental results reported here. {copyright} {ital 1999 American Institute of Physics.}

  2. Antibiotics in Dutch general practice: nationwide electronic GP database and national reimbursement rates.

    NARCIS (Netherlands)

    Akkerman, A.E.; Kuyvenhoven, M.M.; Verheij, T.J.M.; Dijk, L. van

    2008-01-01

    PURPOSE: In order to assess whether different databases generate information which can be reliable compared with each other, this study aimed to assess to which degree prescribing rates for systemic antibiotics from a nationwide electronic general practitioner (GP) database correspond with national

  3. Strain localization band width evolution by electronic speckle pattern interferometry strain rate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Guelorget, Bruno [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)], E-mail: bruno.guelorget@utt.fr; Francois, Manuel; Montay, Guillaume [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)

    2009-04-15

    In this paper, electronic speckle pattern interferometry strain rate measurements are used to quantify the width of the strain localization band, which occurs when a sheet specimen is submitted to tension. It is shown that the width of this band decreases with increasing strain. Just before fracture, this measured width is about five times wider than the shear band and the initial sheet thickness.

  4. Optimization of the ATLAS (s)MDT readout electronics for high counting rates

    Energy Technology Data Exchange (ETDEWEB)

    Kortner, Oliver; Kroha, Hubert; Nowak, Sebastian; Schmidt-Sommerfeld, Korbinian [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Muenchen (Germany)

    2016-07-01

    In the ATLAS muon spectrometer, Monitored Drift Tube (MDT) chambers are used for precise muon track measurement. For the high background rates expected at HL-LHC, which are mainly due to neutrons and photons produced by interactions of the proton collision products in the detector and shielding, new small-diameter muon drift tube (sMDT)-chambers with half the drift tube diameter of the MDT-chambers and ten times higher rate capability have been developed. The standard MDT readout electronics uses bipolar shaping in front of a discriminator. This shaping leads to an undershoot of same charge but opposite polarity following each pulse. With count rates also the probability of having the subsequent pulse in this undershoot increases, which leads to losses in efficiency and spatial resolution. In order to decrease this effect, discrete prototype electronics including Baseline Restoration has been developed. Results of their tests and data taken with them during muon beamtime measurements at CERN's Gamma Irradiation Facility will be presented. which causes a deterioration of signal pulses by preceding background hits, leading to losses in muon efficiency and drift tube spatial resolution. In order to mitigate these so-called signal pile-up effects, new readout electronics with active baseline restoration (BLR) is under development. Discrete prototype electronics with BLR functionality has been tested in laboratory measurements and in the Gamma Irradiation Facility at CERN under high γ-irradiation rates. Results of the measurements are presented.

  5. Comparisons of electronic and visual ratings of strawberry leaves inoculated with two colletotrichum species

    Science.gov (United States)

    Inoculation of detached strawberry leaves with Colletotrichum species may provide a rapid and accurate method for identifying anthracnose resistant germplasm. The purpose of this study was to compare electronic and visual rating methods of screening for anthracnose resistance. Eight to 17 detached...

  6. The Effect of LUMO Level Offset on the Electron Dissociation Rates in Low Bandgap Polymer Heterostructures

    Science.gov (United States)

    Sfeir, Matthew; Rodovsky, Deanna; Azoulay, Jason; Bazan, Guillermo; Peet, Jeffrey

    2012-02-01

    In order to maximize the efficiency of polymer/fullerene bulk heterojunction solar cells, the voltage lost when the electron transfers from the polymer to the fullerene must be minimized. While the magnitude of this loss will significantly impact the maximum attainable efficiency of this technology, there have been relatively few attempts to quantify the dependence of the electron transfer rate and yield on the driving force for electron transfer. In order to isolate the effect of electrochemical potential difference on the exciton dissociation rate, we present results of photophysical measurements of a low bandgap copolymer mixed with a series of fullerene based acceptor materials in a bulk heterojunction geometry. The LUMO level of the acceptor material is varied relative to the polymer's so that the effect of the energy offset on the electron dissociation rate can be determined. Using photoluminescence and transient absorption measurements, we find that the exciton quenching rate varies systematically with increasing energy offset. We examine the mechanism of charge carrier generation by correlating the exciton quenching with charge carrier generation.

  7. Investigation by high resolution electron spectroscopy of the helium-like 3lnl' Rydberg series in double capture processes at low collision velocity: auto transfer to Rydberg states and electron stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Gonzalez, A.; Benhenni, M. (Toulouse-3 Univ., 31 (France)); Bachau, H.; Sanchez, I. (Bordeaux-1 Univ., 33 - Talence (France). Lab. des Collisions Atomiques)

    1994-09-28

    A high resolution electron spectrometry of the (3lnl') Ryberg series populated in N[sup 7+] + He and Ne[sup 10+] + He collisions at 10 q keV, 10[sup o] allows us to observe, for the first time by this method, two post-collisional effects. First, it is found with nitrogen ions that, when n increases from n = 4 to 9, the L-distribution peaks more and more on the high angular momentum states. This is qualitatively understood as a Stark deformation of the Rydberg orbit by the Coulomb field of the receding ion. Also, in the n range where the double capture process populates symmetrical 4l4l' states (n>9), an enhancement of the intensities of the 3lnl' Rydberg lines is observed for both collisonal systems. This is thought to be a signature of the so-called auto transfer to Rydberg states effect. The transfer of population from the 3l4l' to the 3lnl' states is found to be favoured against a direct autoionization of these 4l4l' states into the n = 2 continuum. These experimental findings together with preliminary spectroscopic calculations concerning the configuration interaction of the Ne[sup 8+] (4l4l') states with the Ne[sup 8+](3lnl') Rydberg series are also discussed within the context of the electron stabilization which follows a double capture. (Author).

  8. Capturing the Future: Direct and Indirect Probes of Neutron Capture

    Energy Technology Data Exchange (ETDEWEB)

    Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-31

    This report documents aspects of direct and indirect neutron capture. The importance of neutron capture rates and methods to determine them are presented. The following conclusions are drawn: direct neutron capture measurements remain a backbone of experimental study; work is being done to take increased advantage of indirect methods for neutron capture; both instrumentation and facilities are making new measurements possible; more work is needed on the nuclear theory side to understand what is needed furthest from stability.

  9. The final fate of stars that ignite neon and oxygen off-center: electron capture or iron core-collapse supernova?

    CERN Document Server

    Jones, Samuel; Nomoto, Ken'ichi

    2014-01-01

    In the ONeMg cores of $8.8-9.5~{\\rm M}_\\odot$ stars, neon and oxygen burning is ignited off-center. Whether the neon-oxygen flame propagates to the center is critical to determine whether these stars undergo Fe core collapse or electron capture induced ONeMg core collapse. We present more details of stars that ignite neon and oxygen burning off-center. The neon flame is established in a similar manner to the carbon flame of super-AGB stars, albeit with a narrower flame width. The criteria for establishing a flame are able to be met if the strict Schwarzschild criterion for convective instability is adopted. Mixing across the interface of the convective shell disrupts the conditions for the propagation of the burning front and instead the shell burns as a series of inward-moving flashes. While this may not directly affect whether the burning will reach the center (as in super-AGB stars), the core is allowed to contract between each shell flash. Reduction of the electron fraction in the shell reduces the Chandr...

  10. Measurement of Decay Rate Variation of ~7Be in Pt and Al

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Electron capture (EC) decay rates depend sensitively on the density of atomic electrons within the nucleus. Thus, physically and chemically environmental factors which can change electron densities, ma

  11. Growth rate enhancement of free-electron laser by two consecutive wigglers with axial magnetic field

    Indian Academy of Sciences (India)

    A Hasanbeigi; A Farhadian; E Khademi Bidhendi

    2014-06-01

    The operative mechanism for a free-electron laser (FEL) with two consecutive helical wigglers having opposite circular polarization in the presence of an axial magnetic field is proposed and analysed. With the help of fluid theory, a tenth-degree polynomial dispersion equation for electromagnetic and space-charge waves is derived. The results are used to illustrate and discuss the dependence of growth rate on different system parameters. Finally, it is shown that for the same system parameters the growth rate of the proposed structure is more than the growth rate of instability in a conventional FEL.

  12. Modification of atomic physics rates due to nonlocal electron parallel heat transport in divertor plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Allais, F. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Matte, J.P. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada)]. E-mail: matte@inrs-emt.uquebec.ca; Alouani-Bibi, F. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Kim, C.G. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Stotler, D.P. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Rognlien, T.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2005-03-01

    The effect of steep temperature gradients on the rate of ionization of atomic hydrogen is studied numerically with the electron kinetic code 'FPI' [Phys. Rev. Lett. 72 (1994) 1208]. A set of cross sections ['Atomic and Plasma-Material Interaction data for fusion'. Supplement to the journal Nucl. Fusion 4 (1993)] has been used which gives the same rates of radiation, ionization and recombination as in the well known edge modeling codes 'UEDGE' and 'DEGAS' for Maxwellian electron energy distribution functions. For this purpose, 30 energy levels are included in the computation, as stepwise ionization is dominant. The enhancement of the ionization rate by non-Maxwellian effects in the colder part of the plasma is significant.

  13. Study of the electron → photon misidentification rate in the ATLAS detector

    CERN Document Server

    Haase, Johannes

    In this thesis, the misidentification of electrons as photons (fake rate) is investigated using the first 7 TeV data of the ATLAS detector at the CERN Large Hadron Collider. A method for the measurement of the fake rate in data, using pure electrons from the Z0 → e+e− decay, called tag-and-probe, is presented. The results are studied as functions of kinematic variables in order to show effects on the detector performance. A cross check with a so-called truth-matching method in Monte Carlo is applied. In addition, the fake rate for Gauge Mediated Supersymmetry Breaking events is estimated and compared with Z0 → e+e− studies.

  14. Experiences in running a complex electronic data capture system using mobile phones in a large-scale population trial in southern Nepal.

    Science.gov (United States)

    Style, Sarah; Beard, B James; Harris-Fry, Helen; Sengupta, Aman; Jha, Sonali; Shrestha, Bhim P; Rai, Anjana; Paudel, Vikas; Thondoo, Meelan; Pulkki-Brannstrom, Anni-Maria; Skordis-Worrall, Jolene; Manandhar, Dharma S; Costello, Anthony; Saville, Naomi M

    2017-01-01

    The increasing availability and capabilities of mobile phones make them a feasible means of data collection. Electronic Data Capture (EDC) systems have been used widely for public health monitoring and surveillance activities, but documentation of their use in complicated research studies requiring multiple systems is limited. This paper shares our experiences of designing and implementing a complex multi-component EDC system for a community-based four-armed cluster-Randomised Controlled Trial in the rural plains of Nepal, to help other researchers planning to use EDC for complex studies in low-income settings. We designed and implemented three interrelated mobile phone data collection systems to enrol and follow-up pregnant women (trial participants), and to support the implementation of trial interventions (women's groups, food and cash transfers). 720 field staff used basic phones to send simple coded text messages, 539 women's group facilitators used Android smartphones with Open Data Kit Collect, and 112 Interviewers, Coordinators and Supervisors used smartphones with CommCare. Barcoded photo ID cards encoded with participant information were generated for each enrolled woman. Automated systems were developed to download, recode and merge data for nearly real-time access by researchers. The systems were successfully rolled out and used by 1371 staff. A total of 25,089 pregnant women were enrolled, and 17,839 follow-up forms completed. Women's group facilitators recorded 5717 women's groups and the distribution of 14,647 food and 13,482 cash transfers. Using EDC sped up data collection and processing, although time needed for programming and set-up delayed the study inception. EDC using three interlinked mobile data management systems (FrontlineSMS, ODK and CommCare) was a feasible and effective method of data capture in a complex large-scale trial in the plains of Nepal. Despite challenges including prolonged set-up times, the systems met multiple data

  15. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of chlorinated pesticides in aquatic tissue by capillary-column gas chromatography with electron-capture detection

    Science.gov (United States)

    Leiker, Thomas J.; Madsen, J.E.; Deacon, J.R.; Foreman, W.T.

    1995-01-01

    A method for the determination of chlorinated organic compounds in aquatic tissue by dual capillary-column gas chromatography with electron-capture detection is described. Whole-body-fish or corbicula tissue is homogenized, Soxhlet extracted, lipid removed by gel permeation chromatography, and fractionated using alumina/silica adsorption chromatography. The extracts are analyzed by dissimilar capillary-column gas chromatography with electron-capture detection. The method reporting limits are 5 micrograms per kilogram (μg/kg) for chlorinated compounds, 50 μg/kg for polychlorinated biphenyls, and 200 μg/kg for toxaphene.

  16. Measurement of the total cross sections for electron capture of 2. 0-7. 5 MeV H/sup +/ in H, H/sub 2/ and He

    Energy Technology Data Exchange (ETDEWEB)

    Schwab, W.; Baptista, G.B.; Justiniano, E.; Vogt, H.; Weber, E.W.; Schuch, R.

    1987-06-28

    The total cross sections for electron capture of protons in atomic and molecular hydrogen and in helium gas targets are measured in the high proton velocity regime of 2.0, 3.5, 5.0 and 7.5 MeV. The results are compared with first- and higher-order perturbation theories (Oppenheimer-Brinkmann-Kramers, true first Born approximation (TFBA), eikonal approximation (EA), continuum distorted wave (CDW), strong potential Born, strong potential Born full peaking) for electron capture, and are found to be in good agreement with the CDW, EA and TFBA approximations.

  17. High-repetition rate relativistic electron beam generation from intense laser solid interactions

    Science.gov (United States)

    Batson, Thomas; Nees, John; Hou, Bixue; Thomas, A. G. R.; Krushelnick, Karl

    2015-05-01

    Relativistic electron beams have applications spanning materials science, medicine, and home- land security. Recent advances in short pulse laser technology have enabled the production of very high focused intensities at kHz rep rates. Consequently this has led to the generation of high ux sources of relativistic electrons- which is a necessary characteristic of these laser plasma sources for any potential application. In our experiments, through the generation of a plasma with the lambda cubed laser system at the University of Michigan (a 5 × 1018W=cm2, 500 Hz, Ti:Sapphire laser), we have measured electrons ejected from the surface of fused silica nd Cu targets having energies in excess of an MeV. The spectrum of these electrons was measured with respect to incident laser angle, prepulse timing, and focusing conditions. While taken at a high repetition rate, the pulse energy of the lambda cubed system was consistently on the order of 10 mJ. In order to predict scaling of the electron energy with laser pulse energy, simulations are underway which compare the spectrum generated with the lambda cubed system to the predicted spectrum generated on the petawatt scale HERCULES laser system at the University of Michigan.

  18. Rate coefficients for dissociative attachment and resonant electron-impact dissociation involving vibrationally excited O{sub 2} molecules

    Energy Technology Data Exchange (ETDEWEB)

    Laporta, V. [Istituto di Metodologie Inorganiche e dei Plasmi, CNR, Bari, Italy and Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Celiberto, R. [Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica, Politecnico di Bari, Italy and Istituto di Metodologie Inorganiche e dei Plasmi, CNR, Bari (Italy); Tennyson, J. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2014-12-09

    Rate coefficients for dissociative electron attachment and electron-impact dissociation processes, involving vibrationally excited molecular oxygen, are presented. Analytical fits of the calculated numerical data, useful in the applications, are also provided.

  19. Electron-ion dissociative recombination rate constants relevant to the Titan atmosphere and the Interstellar Medium

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, David; Lawson, Patrick; Adams, Nigel, E-mail: ngadams@uga.edu [University of Georgia, Department of Chemistry, 101 Cedar St., Athens, Georgia 30602 (United States)

    2014-01-21

    Following the arrival of Cassini at Titan in 2004, the Titan atmosphere has been shown to contain large complex polycyclic-aromatic hydrocarbons. Since Cassini has provided a great deal of data, there exists a need for kinetic rate data to help with modeling this atmosphere. One type of kinetic data needed is electron-ion dissociative recombination (e-IDR) rate constants. These data are not readily available for larger compounds, such as naphthalene, or oxygen containing compounds, such as 1,4 dioxane or furan. Here, the rate constants for naphthalene, 1,4 dioxane, and furan have been measured and their temperature dependencies are determined when possible, using the University of Georgia's Variable Temperature Flowing Afterglow. The rate constants are compared with those previously published for other compounds; these show trends which illustrate the effects which multi-rings and oxygen heteroatoms substitutions have upon e-IDR rate constants.

  20. The Dose Rate Dependence of the Yield of Trapped Electrons in Crystalline Ice

    DEFF Research Database (Denmark)

    Nilsson, Johan Daniel Göran; Pagsberg, Palle Bjørn

    1980-01-01

    for the experimental dose rate dependence observed at −10° C. The reaction with the protons has a negative temperature coefficient while the reaction with the OH radicals has an activation energy of about 14 kcal mole−1. The mobility of the proton was estimated to be about 3 × 10−4 cm2 V−1 S−1 at −10°C.......The yield of localized excess electrons in crystalline H2O ice has been studied as a function of the dose rate at various temperatures in the range −10 to −40°C. The G value was found to decrease significantly with increasing dose rate. Thus it appears that the localization of electrons takes place...... in competition with other reactions and we propose a simple model where we assume that the mobile electrons can undergo bimolecular bulk reactions with protons and OH radicals. Rate constants of 3.0 × 1015 M−1 S−1 and 1.4 × 1014 M−1 S−1 for the two reactions were required in the model in order to account...

  1. Quantum chemical calculations of tryptophan → heme electron and excitation energy transfer rates in myoglobin.

    Science.gov (United States)

    Suess, Christian J; Hirst, Jonathan D; Besley, Nicholas A

    2017-04-01

    The development of optical multidimensional spectroscopic techniques has opened up new possibilities for the study of biological processes. Recently, ultrafast two-dimensional ultraviolet spectroscopy experiments have determined the rates of tryptophan → heme electron transfer and excitation energy transfer for the two tryptophan residues in myoglobin (Consani et al., Science, 2013, 339, 1586). Here, we show that accurate prediction of these rates can be achieved using Marcus theory in conjunction with time-dependent density functional theory. Key intermediate residues between the donor and acceptor are identified, and in particular the residues Val68 and Ile75 play a critical role in calculations of the electron coupling matrix elements. Our calculations demonstrate how small changes in structure can have a large effect on the rates, and show that the different rates of electron transfer are dictated by the distance between the heme and tryptophan residues, while for excitation energy transfer the orientation of the tryptophan residues relative to the heme is important. © 2017 The Authors Journal of Computational Chemistry Published by Wiley Periodicals, Inc.

  2. Photon spectroscopy of X{sup 7+} ions (X= Ne, Ar, Kr). Applications to the study of the single electron capture in low energy X{sup 8+}-Li collisions; Spectroscopie photonique des ions X{sup 7+} (X=Ne, Ar, Kr). Applications a l`etude de la simple capture electronique lors des collisions X{sup 8+}-Li a basse energie

    Energy Technology Data Exchange (ETDEWEB)

    Pascale, J. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Recherche sur l`Etat Condense, les Atomes et les Molecules; Jacquet, E. [Caen Univ., 14 (France). Lab. de Spectroscopie Atomique

    1994-12-31

    The effect of the electronic core of the projectile ion on the single capture electron n1 final states during collisions between X{sup 8+} ions (X= Ne, Ar, Kr) and Li(2s). Experimental cross sections are obtained from X{sup 7+} emission line measurements and are compared to calculations using the Monte Carlo type classical trajectory method. 3 figs., 6 refs.

  3. Enhanced rate of intramolecular electron transfer in an engineered purple CuA azurin

    DEFF Research Database (Denmark)

    Farver, O; Lu, Y; Ang, M C

    1999-01-01

    V for blue copper azurin). The reorganization energy of the CuA center is calculated to be 0.4 eV, which is only 50% of that found for the wild-type azurin. These results represent a direct comparison of electron transfer properties of the blue and purple CuA sites in the same protein framework and provide...... and CuA centers are placed in the same location in the protein while all other structural elements remain the same. Long-range electron transfer is induced between the disulfide radical anion, produced pulse radiolytically, and the oxidized binuclear CuA center in the purple azurin mutant. The rate...... support for the notion that the binuclear purple CuA center is a more efficient electron transfer agent than the blue single copper center because reactivity of the former involves a lower reorganization energy....

  4. SLIP RATE ESTIMATION FOR VEHICLE STABILITY ENHANCEMENT USING FUZZY BASED ELECTRONIC DIFFERENTIAL CONTROLLER

    Directory of Open Access Journals (Sweden)

    A. RAVI

    2015-11-01

    Full Text Available Fuzzy Logic based Electronic Differential Controller (FLEDC for sensorless drive based electric vehicle is presented. The proposed system consists of two Brushless DC motors (BLDC that ensure the drive of the two back driving wheels of an electric vehicle. Electronic Differential Controller (EDC can control both the driving wheel independently to turn at different speeds in any curve according to the steering angle. The sensorless control strategies include back EMF zero crossing detection and third harmonic voltage integration are used to analyse the proposed system. Fuzzy logic based EDC is used on these sensorless control strategies which optimizes the slip rate within the specified limit. To enhances the vehicle stability, the performances in terms of optimum value of slip rate and also current, torque, back EMF are obtained by the proposed method. By this investigation, a suitable control strategy has been identified and also experimentally validated.

  5. On the validity of the Arrhenius equation for electron attachment rate coefficients.

    Science.gov (United States)

    Fabrikant, Ilya I; Hotop, Hartmut

    2008-03-28

    The validity of the Arrhenius equation for dissociative electron attachment rate coefficients is investigated. A general analysis allows us to obtain estimates of the upper temperature bound for the range of validity of the Arrhenius equation in the endothermic case and both lower and upper bounds in the exothermic case with a reaction barrier. The results of the general discussion are illustrated by numerical examples whereby the rate coefficient, as a function of temperature for dissociative electron attachment, is calculated using the resonance R-matrix theory. In the endothermic case, the activation energy in the Arrhenius equation is close to the threshold energy, whereas in the case of exothermic reactions with an intermediate barrier, the activation energy is found to be substantially lower than the barrier height.

  6. Muon capture in deuterium

    Science.gov (United States)

    Ricci, P.; Truhlík, E.; Mosconi, B.; Smejkal, J.

    2010-06-01

    Model dependence of the capture rates of the negative muon capture in deuterium is studied starting from potential models and the weak two-body meson exchange currents constructed in the tree approximation and also from an effective field theory. The tree one-boson exchange currents are derived from the hard pion chiral Lagrangians of the NΔπρωa system. If constructed in conjunction with the one-boson exchange potentials, the capture rates can be calculated consistently. On the other hand, the effective field theory currents, constructed within the heavy baryon chiral perturbation theory, contain a low energy constant d that cannot be extracted from data at the one-particle level nor determined from the first principles. Comparative analysis of the results for the doublet transition rate allows us to extract the constant d.

  7. An experiment to measure the electron-ion thermal equilibration rate in a strongly coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Taccetti, J M; Shurter, R P; Roberts, J P; Benage, J F; Graden, B; Haberle, B; Murillo, M S; Vigil, B; Wysocki, F J [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2006-04-28

    We present the most recent results from an experiment aimed at obtaining the temperature equilibration rate between ions and electrons in a strongly coupled plasma by directly measuring the temperature of each component. The plasma is formed by heating a sonic gas jet with a 10 ps laser pulse. The electrons are preferentially heated by the short pulse laser (we are aiming for T{sub e} {approx} 100 eV), while the ions, after undergoing very rapid (sub-ps timescale) disorder-induced heating, should only reach a temperature of 10-15 eV. This results in a strongly coupled ion plasma with a {gamma}{sub ii} {approx} 3-5. We plan to measure the electron and ion temperatures of the resulting plasma independently during and after heating, using collective Thomson scattering for electrons and a high-resolution x-ray spectrometer for the ions (measuring Doppler-broadened absorption lines). Theory indicates that the equilibration rate could be significantly lower than that given by the usual weakly coupled model (Landau-Spitzer) due to coupled collective modes present in the dense plasma.

  8. An experiment to measure the electron ion thermal equilibration rate in a strongly coupled plasma

    Science.gov (United States)

    Taccetti, J. M.; Shurter, R. P.; Roberts, J. P.; Benage, J. F.; Graden, B.; Haberle, B.; Murillo, M. S.; Vigil, B.; Wysocki, F. J.

    2006-04-01

    We present the most recent results from an experiment aimed at obtaining the temperature equilibration rate between ions and electrons in a strongly coupled plasma by directly measuring the temperature of each component. The plasma is formed by heating a sonic gas jet with a 10 ps laser pulse. The electrons are preferentially heated by the short pulse laser (we are aiming for Te ~ 100 eV), while the ions, after undergoing very rapid (sub-ps timescale) disorder-induced heating, should only reach a temperature of 10-15 eV. This results in a strongly coupled ion plasma with a Γii ~ 3-5. We plan to measure the electron and ion temperatures of the resulting plasma independently during and after heating, using collective Thomson scattering for electrons and a high-resolution x-ray spectrometer for the ions (measuring Doppler-broadened absorption lines). Theory indicates that the equilibration rate could be significantly lower than that given by the usual weakly coupled model (Landau-Spitzer) due to coupled collective modes present in the dense plasma.

  9. Measurement of the Electron-Ion Temperature Relaxation Rate in a Dense Plasma

    Science.gov (United States)

    Taccetti, J. M.; Shurter, R. P.; Goodwin, P. M.; Benage, J. F., Jr.

    2008-11-01

    Current theoretical approaches to temperature relaxation, which can be categorized as binary-collision and many-body approaches, disagree. Existing experimental evidence infers a lower relaxation rate compared to the binary-collision approach, but is insufficient to determine which approach is correct. We present the most recent results from an experiment aimed at obtaining the temperature relaxation rate between ions and electrons in a dense, strongly coupled plasma by directly measuring the temperature of each component. The plasma is formed by heating a gas jet with a 10 ps laser pulse. The electrons are preferentially heated by the short pulse laser (Te 100 eV), while the ions, after undergoing very rapid (sub-ps time-scale) disorder-induced heating, should only reach a temperature of 10-15 eV. This results in a strongly coupled ion plasma with an ion-ion coupling parameter γii 3-5. We plan to measure the electron and ion temperatures of the resulting plasma independently during and after heating, using collective Thomson scattering for electrons and a high-resolution x-ray spectrometer for the ions (measuring Doppler-broadened absorption lines).

  10. Capture and Fission rate of 232-Th, 238-U, 237-Np and 239-Pu from spallation neutrons in a huge block of lead.

    CERN Document Server

    Vlachoudis, Vasilis

    2000-01-01

    The study is centered on the research of the incineration possibility of nuclear waste, by the association of a particle accelerator with a multiplying medium of neutrons, in the project "Energy Amplifier" of C. Rubbia. It consists of the experimental determination of the rates of capture and fission of certain elements (232-Th, 238-U, 237-Np and 239-Pu) subjected to a fluence of fast spallation neutrons. These neutrons are produced by the interaction of high kinetic energy protons (several GeV) provided by the CERN-PS accelerator, on a large lead solid volume. The measurement techniques used in this work, are based on the activation of elements in the lead volume and the subsequent gamma spectroscopy of the activated elements, and also by the detection of fission fragment traces. The development, of a Monte Carlo code makes it possible, on one hand, to better understand the relevant processes, and on the other hand, to validate the code, by comparison with measurements, for the design and the construction of...

  11. Rating of Everyday Arm-Use in the Community and Home (REACH scale for capturing affected arm-use after stroke: development, reliability, and validity.

    Directory of Open Access Journals (Sweden)

    Lisa A Simpson

    Full Text Available OBJECTIVE: To develop a brief, valid and reliable tool [the Rating of Everyday Arm-use in the Community and Home (REACH scale] to classify affected upper limb use after stroke outside the clinical setting. METHODS: Focus groups with clinicians, patients and caregivers (n = 33 and a literature review were employed to develop the REACH scale. A sample of community-dwelling individuals with stroke was used to assess the validity (n = 96 and inter-rater reliability (n = 73 of the new scale. RESULTS: The REACH consists of separate scales for dominant and non-dominant affected upper limbs, and takes five minutes to administer. Each scale consists of six categories that capture 'no use' to 'full use'. The intraclass correlation coefficient and weighted kappa for inter-rater reliability were 0.97 (95% confidence interval: 0.95-0.98 and 0.91 (0.89-0.93 respectively. REACH scores correlated with external measures of upper extremity use, function and impairment (rho = 0.64-0.94. CONCLUSIONS: The REACH scale is a reliable, quick-to-administer tool that has strong relationships to other measures of upper limb use, function and impairment. By providing a rich description of how the affected upper limb is used outside of the clinical setting, the REACH scale fills an important gap among current measures of upper limb use and is useful for understanding the long term effects of stroke rehabilitation.

  12. Strain rate measurement by Electronic Speckle Pattern Interferometry: A new look at the strain localization onset

    Energy Technology Data Exchange (ETDEWEB)

    Guelorget, Bruno [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)]. E-mail: bruno.guelorget@utt.fr; Francois, Manuel [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Vial-Edwards, Cristian [Departemento de Ingenieria Mecanica y Metalurgica, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, 6904411 Santiago (Chile); Montay, Guillaume [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Daniel, Laurent [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Lu, Jian [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)

    2006-01-15

    In-plane Electronic Speckle Pattern Interferometry has been successfully used during tensile testing of semi-hard copper sheets in order to measure the strain rate. On one hand, heterogeneity in strain rate field has been found before the maximum of the tensile force ({epsilon} {sup t} {approx_equal} 19.4 and 25.4%, respectively). Thus, a localization phenomenon occurs before the classic Considere's criterion (dF = 0) for the diffuse neck initiation. On the other hand, strain rate measurement before fracture shows the moment where one of the two slip band systems becomes predominant, then strain concentrates in a small area, the shear band. Uncertainty evaluation has been carried out, which shows a very good accuracy of the total strain and the strain rate measurements.

  13. IMPAC OF VOLATILITY EXCHANGE RATES ON INDONESIAN ELECTRONIC IMPORTS FROM INTRA AND EXTRA ASEAN

    Directory of Open Access Journals (Sweden)

    Imam Muklis

    2011-09-01

    Full Text Available This study analyzes the effects of exchange rates volatility and Gross Domestic Product (GDP onelectronic commodity import demand in Indonesia from intra and extra ASEAN. It applies an ErrorCorrection Model along with Dickey-Fuller and Augmented Dickey-Fuller tests. It finds that Indonesianimport demand for electronic commodity is significantly affected by GDP only in the shortrun. It also finds that exchange rates volatility in the short run have a negative effect on import demandfrom intra ASEAN and have a positive effect from extra ASEAN. In the long term, Indonesianimport demand from extra ASEAN is positively affected only by exchange rates volatility.Keywords: Exchange rates volatility, error correction model, gross domestic product, ASEANJEL classification numbers: F14, F31

  14. Toward the understanding of chemical absorption processes for post-combustion capture of carbon dioxide: electronic and steric considerations from the kinetics of reactions of CO2(aq) with sterically hindered amines.

    Science.gov (United States)

    Conway, William; Wang, Xiaoguang; Fernandes, Debra; Burns, Robert; Lawrance, Geoffrey; Puxty, Graeme; Maeder, Marcel

    2013-01-15

    The present study reports (a) the determination of both the kinetic rate constants and equilibrium constants for the reaction of CO(2)(aq) with sterically hindered amines and (b) an attempt to elucidate a fundamental chemical understanding of the relationship between the amine structure and chemical properties of the amine that are relevant for postcombustion capture of CO(2) (PCC) applications. The reactions of CO(2)(aq) with a series of linear and methyl substituted primary amines and alkanolamines have been investigated using stopped-flow spectrophotometry and (1)H NMR measurements at 25.0 °C. The specific mechanism of absorption for each of the amines, that is CO(2) hydration and/or carbamate formation, is examined and, based on the mechanism, the kinetic and equilibrium constants for the formation of carbamic acid/carbamates, including protonation constants of the carbamate, are reported for amines that follow this pathway. A Brønsted correlation relating the kinetic rate constants and equilibrium constants for the formation of carbamic acid/carbamates with the protonation constant of the amine is reported. Such a relationship facilitates an understanding of the effects of steric and electronic properties of the amine toward its reactivity with CO(2). Further, such relationships can be used to guide the design of new amines with improved properties relevant to PCC applications.

  15. Consequences of light absorptance in calculating electron transport rate of desert and succulent plants

    OpenAIRE

    Stemke, JA; Santiago, LS

    2011-01-01

    The proportional light absorptance by photosynthetic tissue (α) is used with chlorophyll (Chl) fluorescence methods to calculate electron transport rate (ETR). Although a value of α of 0.84 is often used as a standard for calculating ETR, many succulent plant species and species with crassulacean acid metabolism (CAM) have photosynthetic tissues that vary greatly in color or are highly reflective, and could have values of α that differ from 0.84, thus affecting the calculation of ETR. We meas...

  16. Recombination and Electron Impact Excitation Rate Coefficients for S XV and S XVI

    Science.gov (United States)

    Mahmood, S.; Ali, S.; Orban, I.; Tashenov, S.; Lindroth, E.; Schuch, R.

    2012-08-01

    Recombination and electron impact excitation of S14+ and S15+ ions was measured at the Stockholm refrigerated electron beam ion trap. The collision energy range was 1.4-3 keV, in which we covered the KLL, KLM, KLN, and KLO dielectronic recombination resonances resulting in S13+ and S14+ ions. The recombination rates were obtained by detecting the charge state distribution with a newly developed time-of-flight technique. Resonance energies and cross-sections calculated within the relativistic many-body perturbation theory for S15+ agree well with the experimental data. The temperature-dependent rate coefficients were extracted from the measured rates and compared with calculations from the literature used for studies of collisionally ionized astrophysical plasmas. Good agreement for S15+ was obtained, while the plasma rates for S14+ were 23% lower than the current published values. In addition to the time-of-flight spectra, the X-ray spectra, produced mainly by photo-recombination and excitation, were also collected. The combination of these two measurements allowed us to separate the photo-recombination and the excitation spectra, and the excitation rate coefficients for summed intensities with known fractions of S14+ and S15+ ions were extracted.

  17. Dispersive Liquid-Liquid Microextraction Based on Solidification of Floating Organic Drop Followed by Gas Chromatography-Electron Capture Detector for Determination of Some Pesticides in Water Samples

    Directory of Open Access Journals (Sweden)

    Mostafa Bashiri Juybari

    2011-01-01

    Full Text Available In this study dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO followed by gas chromatography-electron capture detection (GC-ECD was developed for determination of some pesticides in the water samples. Some important parameters, such as type and volumes of extraction and disperser solvent and salt effect on the extraction recovery of analytes from aqueous solution were investigated. Under the optimum conditions (extraction solvent: 1-undecanol, 15.0 μL; disperser solvent: acetone, 1.0 mL, and without salt addition, the preconcentration factors were obtained ranged from 802 to 915 for analytes. The linear ranges were from 0.05 to 100 μg L−1, and detection limits ranged from 0.05 to 0.008 μg L−1. The relative standard deviations (RSDs%, =5 were between 3.2% and 6.7%. The proposed method was successfully applied to the determination of target analytes in the tap, sea, and river water samples, and satisfactory recoveries were obtained.

  18. Use of green coating (cork) in solid-phase microextraction for the determination of organochlorine pesticides in water by gas chromatography-electron capture detection.

    Science.gov (United States)

    Dias, Adriana Neves; Simão, Vanessa; Merib, Josias; Carasek, Eduardo

    2015-03-01

    A novel method for the determination of organochlorine pesticides in water samples with extraction using cork fiber and analysis by gas chromatography with electron capture detector was developed. Also, the procedure to extract these pesticides with DVB/Car/PDMS fiber was optimized. The optimization of the variables involved in the extraction of organochlorine pesticides using the aforementioned fibers was carried out by multivariate design. The optimum extraction conditions were sample temperature 75 °C, extraction time 60 min and sodium chloride concentration 10% for the cork fiber and sample temperature 50 °C and extraction time 60 min (without salt) for the DVB/Car/PDMS fiber. The quantification limits for the two fibers varied between 1.0 and 10.0 ng L(-1). The linear correlation coefficients were >0.98 for both fibers. The method applied with the use of the cork fiber provided recovery values between 60.3 and 112.7 and RSD≤25.5 (n=3). The extraction efficiency values for the cork and DVB/Car/PDMS fibers were similar. The results show that cork is a promising alternative as a coating for SPME.

  19. Application of the standard addition method for the determination of acrylamide in heat-processed starchy foods by gas chromatography with electron capture detector.

    Science.gov (United States)

    Zhu, Yonghong; Li, Genrong; Duan, Yunpeng; Chen, Shiqi; Zhang, Chun; Li, Yanfei

    2008-08-15

    A gas chromatography electron capture detector (GC-ECD) using the standard addition method was developed for the determination of acrylamide in heat-processed foods. The method entails extraction of acrylamide with water, filtration, defatting with n-hexane, derivatization with hydrobromic acid and saturated bromine-water, and liquid-liquid extraction with ethyl acetate. The sample pretreatment required no SPE clean-up and concentration steps prior to injection. The final extract was analyzed by GC-ECD. The chromatographic analysis was performed on polar columns, e.g. Supelcowax-10 capillary column, and good retention and peak response of the analyte were achieved under the optimal conditions. The qualification of the analyte was by identifying the peak with same retention time as standard compound 2,3-DBPA and confirmed by GC-MS. GC-MS analysis confirmed that 2,3-DBPA was converted to 2-BPA nearly completely on the polar capillary column, whether or not treated with triethylamine. A four-point standard addition protocol was used to quantify acrylamide in food samples. The limit of detection (LOD) was estimated to be 0.6μg/kg on the basis of ECD technique. Validation and quantification results demonstrated that the method should be regarded as a low-cost, convenient, and reliable alternative for conventional investigation of acrylamide.

  20. Group-selective enrichment and determination of pyrethroid insecticides in aquaculture seawater via molecularly imprinted solid phase extraction coupled with gas chromatography-electron capture detection.

    Science.gov (United States)

    Shi, Xizhi; Liu, Jinghua; Sun, Aili; Li, Dexiang; Chen, Jiong

    2012-03-02

    Two types of molecularly imprinted polymers (MIPs) for the simultaneous determination of six pyrethroid insecticides have been developed using deltamethrin (D-MIPs) and cypermethrin (C-MIPs) as template molecules. A comparison of the performance of D-MIPs, C-MIPs, and the corresponding non-imprinted polymers (NIPs) were conducted. Stronger group-selective interactions between the C-MIPs and the six pyrethroid insecticides were achieved. The MISPE method based on the C-MIPs displayed higher extraction recoveries (86.4-96.0%) with RSD values ranging from 2.4 to 7.8% for the six pyrethroid insecticides in aquaculture seawater. After the C-MIP cartridge procedure, the limits of detection and quantification for fenvalerate, deltamethrin, cypermethrin, cyfluthrin, and bifenthrin were in the 16.6-37.0 and 55.3-109.1 ng L⁻¹ ranges, respectively, and 0.68 and 2.26 μg L⁻¹ for phenothrin, respectively. The proposed MISPE method coupled with gas chromatography-electron capture detection was successfully used for the determination of the six pyrethroid insecticides in aquaculture seawater.

  1. Determination of trihalomethanes in soil matrices by simplified quick, easy, cheap, effective, rugged and safe extraction and fast gas chromatography with electron capture detection.

    Science.gov (United States)

    Herrero Martín, Sara; García Pinto, Carmelo; Pérez Pavón, José Luis; Moreno Cordero, Bernardo

    2010-07-23

    A method based on QuEChERS extraction is proposed for the determination of trihalomethanes (chloroform, bromodichloromethane, dibromocloromethane and bromoform) in soil samples. The new version of QuEChERS adapted to soil samples consists of liquid extraction with ethyl acetate, the addition of water to moisten the samples, salting-out partitioning of the water with anhydrous MgSO4, and direct injection of the organic extract, obtained after the centrifugation step, into the gas chromatograph. This simplified extraction procedure maintains the advantages of the original method and avoids some steps, making the final procedure simpler, faster, and cheaper, with the consequent reduction in errors associated with sample manipulation. The experimental conditions of the analytical method, based on fast gas chromatography (FGC) and micro-electron capture detection (microECD), were optimized. The column and oven program used allowed fast separation of the compounds in less than 4 min and the total analysis cycle time was as short as 10 min. The existence of a matrix effect was checked and the analytical conditions of the method were studied in a fortified garden soil sample. The highly sensitive and selective detector used afforded to detection limits in the order of ng/kg for the target compounds. To validate the proposed method two certified reference materials (CRMs) were analyzed.

  2. Measurement of polychlorinated biphenyls in solid waste such as transformer insulation paper by supercritical fluid extraction and gas chromatography electron capture detection.

    Science.gov (United States)

    Chikushi, Hiroaki; Fujii, Yuka; Toda, Kei

    2012-09-21

    In this work, a method for measuring polychlorinated biphenyls (PCBs) in contaminated solid waste was investigated. This waste includes paper that is used in electric transformers to insulate electric components. The PCBs in paper sample were extracted by supercritical fluid extraction and analyzed by gas chromatography-electron capture detection. The recoveries with this method (84-101%) were much higher than those with conventional water extraction (0.08-14%), and were comparable to those with conventional organic solvent extraction. Limit of detection was 0.0074 mg kg(-1) and measurable up to 2.5 mg kg(-1) for 0.5 g of paper sample. Data for real insulation paper by the proposed method agreed well with those by the conventional organic solvent extraction. Extraction from wood and concrete was also investigated and good performance was obtained as well as for paper samples. The supercritical fluid extraction is simpler, faster, and greener than conventional organic solvent extraction. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Semiautomatic method for the screening and determination of 23 organochlorine pesticides in horticultural samples by gas chromatography with electron-capture detection.

    Science.gov (United States)

    Columé, A; Cárdenas, S; Gallego, M; Valcárcel, M

    1999-07-16

    A rapid, simple, efficient device for the extraction-preconcentration of 23 organochlorine pesticides currently applied to vegetables is proposed. Pesticide residues are extracted from chopped samples by using a mixture of distilled water and light petroleum (1:1, v/v). After phase separation, an aliquot of the organic layer is continuously evaporated to dryness under a N2 stream as it is dropped into a glass tube containing distilled water. The aqueous phase, containing the analytes, is then passed through a miniaturized RP-C18 column for preconcentration, clean-up and subsequent elution with 150 microliters of ethyl acetate. A volume of 1 microliter of the extract containing pesticides is injected into the gas chromatograph, fitted with an electron-capture detector, for their selective determination. Limits of detection vary between 0.04 and 10 ng/ml, with linear ranges from 0.2 to 500 ng/ml; the average relative standard deviation at the low nanogram-per-millilitre level is 5.3%. The potential of the proposed method was realized by applying it to the screening/determination of organochlorine pesticides in horticultural commodities.

  4. Searches for massive neutrino emission in 14C beta and 55Fe electron-capture decays

    Energy Technology Data Exchange (ETDEWEB)

    Wietfeldt, Fred Eberhardt [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    In 1985 Simpson reported evidence for the emission of a 17 keV mass neutrino in a small fraction of tritium beta decays. An experimental controversy ensued in which a number of both positive and negative results were reported. The beta spectrum of 14C was collected in a unique 14C-doped planar germanium detector and a distortion was observed that initially confirmed Simpson`s result. Further tests linked this distortion to a splitting of the collected charge between the central detector and the surrounding guard ring in a fraction of the events. A second 14C measurement showed no evidence for emission of a 17 keV mass neutrino. In a related experiment, a high statistics electron-capture internal-bremsstrahlung photon spectrum of 55Fe was collected with a coaxial germanium detector. A local search for departures from a smooth shape near the endpoint was performed, using a second-derivative technique. An upper limit of 0.65% (95% C.L.) for the mixing Of a neutrino in the mass range 5--25 keV was established. The upper limit on the mixing of a 17 keV mass neutrino was 0.14% (95% C.L.).

  5. Comparison of sample preparation methods combined with gas chromatography with electron-capture detection for the analysis of multipesticide residues in lotus seeds.

    Science.gov (United States)

    Miao, Qing; Kong, Weijun; Yang, Shihai; Yang, Meihua

    2013-06-01

    Sample preparation is always the major bottleneck in analytical chemistry for the determination of pesticide residues. Different sample preparation methods have been proposed due to the wide variety of pesticides used and the inherent complexity of the matrices. In this study, different sample preparation methods including SPE, matrix solid-phase dispersion, the quick, easy, cheap, efficient, rugged, and safe method, and a one-step completion method were compared and evaluated for extracting pesticides from lotus seeds. Analysis was carried out using GC with electron-capture detection. The results showed that good recoveries for tested pesticides were obtained by using Florisil in the four methods, and the extraction efficiency of the one-step completion method was superior to the other three methods. The one-step completion method was confirmed to have good linearity, reproducibility, stability, and recovery for the detection of 36 pesticides in lotus seed samples. The data collected from this study are expected to prove useful in regulating the concentration of the residues in lotus seeds, as well as in protecting human health from the hazards posed by these residues.

  6. Phenyl-functionalized silica-coated magnetic nanoparticles for the extraction of chlorobenzenes, and their determination by GC-electron capture detection.

    Science.gov (United States)

    Saraji, Mohammad; Khaje, Nasrin

    2013-03-01

    We have prepared a solid phase for the extraction of chlorobenzenes (CBs) by coating magnetic (Fe3 O4 ) nanoparticles with silica via a sol-gel process using a mixture of tetraethoxysilane and triethoxyphenylsilane. The nanoparticles were characterized by SEM, energy-dispersive spectroscopy, and X-ray diffractometry. The nanoparticles were used for the extraction of 1,4-dichlorobenzene (1,4-DCB), 1,2,3-trichlorobenzene (1,2,3-TCB), 1,2,4-trichlorobenzene (1,2,4-TCB), and 1,2,3,4-tetrachlorobenzene (1,2,3,4-TeCB) from water, followed by their determination by GC-electron capture detection. Under optimal conditions, enrichment factors ranging from 220 to 360 were obtained. All determination coefficients (r(2)) are >0.99, and linear response is found in range 0.025-1.5 μg/L (at the lower end), and 6-120 μg/L (at the higher end). Detection limits are 6, 10, 11, and 500 ng/L for 1,2,3,4-TeCB, 1,2,4-TCB, 1,2,3-TCB, and 1,4-DCB, respectively. All RSDs are <6% (for n = 5). The method was successfully applied to the determination of CBs in environmental water samples.

  7. Solid phase extraction with silicon dioxide microsphere adsorbents in combination with gas chromatography-electron capture detection for the determination of DDT and its metabolites in water samples.

    Science.gov (United States)

    Zhou, Qingxiang; Wu, Wei; Xie, Guohong

    2013-01-01

    The goal of the present study was to investigate the feasibility of silicon dioxide (SiO(2)) microspheres without special modification to enrich dichlorodiphenyltrichloroethane (DDT) and its main metabolites, p,p'-dichlorodiphenyl-2,2-dichloroethylene (p,p'-DDD) and p,p'-dichlorodiphenyldichloroethylene (DDE) in combination with gas chromatography-electron-capture detection. The experimental results indicated that an excellent linear relationship between the recoveries and the concentrations of DDT and its main metabolites was obtained in the range of 0.2-30 ng mL(-1) and the correlation coefficients were in the range of 99.96-99.99%. The detection limits based on the ratio of signal to the baseline noise (S/N = 3) were 2.2, 2.9, 3.8 and 4.1 ng L(-1) for p,p'-DDD, p,p'-DDT, o,p'-DDT, and p,p'-DDE, respectively. The precisions of the proposed method were all below 10% (n = 6). Four real water samples were utilized for validation of the proposed method, and satisfactory spiked recoveries in the range of 72.4-112.9% were achieved. These results demonstrated that the developed method was a simple, sensitive, and robust analytical method for the monitoring of pollutants in the environment.

  8. M-shell electron capture and direct ionization of gold by 25-MeV carbon and 32-MeV oxygen ions

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M.C.; McDaniel, F.D.; Duggan, J.L.; Miller, P.D.; Pepmiller, P.L.; Krause, H.; Rosseel, T.; Rayburn, L.A.; Mehta, R.; Lapicki, G.

    1984-01-01

    M-shell x-ray production cross sections have been measured for thin solid targets of Au for 25 MeV /sup 12/C/sup q+/ (q = 4, 5, 6) and for 32 MeV /sup 16/O/sup q+/ (q = 5, 7, 8). The microscopic cross sections were determined from measurements made with targets ranging in thickness from 0.5 to 100 ..mu..g/cm/sup 2/. For projectiles with one or two K-shell vacancies, the M-shell x-ray production cross sections are found to be enhanced over those by projectiles without a K-shell vacancy. The sum of direct ionization to the continuum (DI) and electron capture (EC) to the L, M, N ... shells and EC to the K-shell of the projectile have been extracted from the data. The results are compared to the predictions of first Born theories i.e. PWBA for DI and OBK of Nikolaev for EC and the ECPSSR approach that accounts for energy loss, Coulomb deflection and relativistic effects in the perturbed stationary state theory. 25 references, 3 figures, 1 table.

  9. E-bra with nanosensors, smart electronics and smart phone communication network for heart rate monitoring

    Science.gov (United States)

    Varadan, Vijay K.; Kumar, Prashanth S.; Oh, Sechang; Mathur, Gyanesh N.; Rai, Pratyush; Kegley, Lauren

    2011-04-01

    Heart related ailments have been a major cause for deaths in both men and women in United States. Since 1985, more women than men have died due to cardiac or cardiovascular ailments for reasons that are not well understood as yet. Lack of a deterministic understanding of this phenomenon makes continuous real time monitoring of cardiovascular health the best approach for both early detection of pathophysiological changes and events indicative of chronic cardiovascular diseases in women. This approach requires sensor systems to be seamlessly mounted on day to day clothing for women. With this application in focus, this paper describes a e-bra platform for sensors towards heart rate monitoring. The sensors, nanomaterial or textile based dry electrodes, capture the heart activity signals in form Electrocardiograph (ECG) and relay it to a compact textile mountable amplifier-wireless transmitter module for relay to a smart phone. The ECG signal, acquired on the smart phone, can be transmitted to the cyber space for post processing. As an example, the paper discusses the heart rate estimation and heart rate variability. The data flow from sensor to smart phone to server (cyber infrastructure) has been discussed. The cyber infrastructure based signal post processing offers an opportunity for automated emergency response that can be initiated from the server or the smartphone itself. Detailed protocols for both the scenarios have been presented and their relevance to the present emergency healthcare response system has been discussed.

  10. Extracting the Electron-Ion Temperature Relaxation Rate from Ion Stopping Experiments

    Science.gov (United States)

    Grabowski, Paul E.; Frenje, Johan A.; Benedict, Lorin X.

    2016-10-01

    Direct measurement of i-e equilibration rates at ICF-relevant conditions is a big challenge, as it is difficult to differentiate from other sinks and sources of energy, such as heat conduction and pdV work. Another method is to use information from ion stopping experiments. Such experiments at the OMEGA laser have made precision energy loss measurements of fusion products at these conditions. Combined with the multimonochromatic x-ray imager technique, which gives temporally and spatially resolved electron temperature and density, we have a robust stopping experiment. We propose to use such stopping measurements to assess the i-e temperature relaxation rate, since both processes involve energy exchange between electrons and ions. We require that the fusion products are 1) much faster than the thermal ions so that i-i collisions are negligible compared to i-e collisions and 2) slower than the thermal electrons so that the stopping obeys a linear friction law. Then the Coulomb logarithms associated with ion stopping and i-e temperature relaxation rate are identical and a measurement of the former provides the latter. Prepared by LLNL under Contract DE-AC52-07NA27344.

  11. The COSMOS [OII] Survey: Evolution of Electron Density with Star Formation Rate

    CERN Document Server

    Kaasinen, Melanie; Groves, Brent; Kewley, Lisa; Gupta, Anshu

    2016-01-01

    Star-forming galaxies at $z > 1$ exhibit significantly different properties to local galaxies of equivalent stellar mass. Not only are high-redshift star-forming galaxies characterized by higher star formation rates and gas fractions than their local counterparts, they also appear to host star-forming regions with significantly different physical conditions, including greater electron densities. To understand what physical mechanisms are responsible for the observed evolution of star-forming conditions we have assembled the largest sample of star-forming galaxies at $z\\sim 1.5$ with emission-line measurements of the $\\mathrm{[OII]} \\lambda \\lambda 3726,3729$ doublet. By comparing our $z\\sim 1.5$ sample to local galaxy samples with equivalent distributions of stellar mass, star formation rate and specific star formation rate we investigate the proposed evolution in electron density and its dependence on global properties. We measure an average electron density of $114_{-27}^{+28} \\, \\mathrm {cm}^{-3} $ for our...

  12. Suitability of magnetic particle immunoassay for the analysis of PBDEs in Hawaiian freshwater fish and crabs in comparison with gas chromatography/electron capture detection-ion trap mass spectrometry

    Science.gov (United States)

    A gas chromatograph/electron capture detector-ion trap mass spectrometer (GC/ECD-ITMS) was used for the determination of polybrominated diphenyl ethers (PBDEs) in freshwater fish and crabs. The samples were also analyzed with an enzyme-linked immunosorbent assay (ELISA). GC/ECD-ITMS results showed...

  13. Separation of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans and 12 dioxin-like polychlorinated biphenyls by comprehensive two-dimensional gas chromatography with electron-capture detection

    NARCIS (Netherlands)

    Korytar, P.; Danielsson, C.; Leonards, P.E.G.; Haglund, P.; Boer, de J.; Brinkman, U.A.Th.

    2004-01-01

    Comprehensive two-dimensional gas chromatography (GCxGC) with electron-capture detection (ECD) has been optimized for the separation of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans and 12 dioxin-like polychlorinated biphenyls, with emphasis on the selection of th

  14. Capturing appearance

    Science.gov (United States)

    Rushmeier, Holly E.

    2005-01-01

    For computer graphics applications, capturing the appearance parameters of objects (reflectance, transmittance and small scale surface structures), is as important as capturing the overall shape. We briefly review recent approaches developed by the computer graphics community to solve this problem. Excellent results have been obtained by various researchers measuring spatially varying reflectance functions for some classes of objects. We will consider some challenges from two of the remaining problematic classes of objects. First we will describe our experience scanning and modeling the throne of Tutankhamen. The major difficulties in this case were that the base shape was a highly detailed non-convex geometry with complex topology, and the shape was covered by optically uncooperative gold and silver. Then we will discuss some observations from our ongoing project to scan and model historic buildings on the Yale campus. The major difficulties in this second case are quantity of data and the lack of control over acquisition conditions.

  15. Solvent effect on intramolecular electron transfer rates of mixed-valence biferrocene monocation derivatives.

    Science.gov (United States)

    Masuda, Y; Shimizu, C

    2006-06-01

    Intramolecular electron transfer (ET) rates in various solvents of mixed-valence biferrocene monocation (Fe(II), Fe(III)) and the 1',1' ''-diiodo and 1',1' ''-diethyl derivatives (respectively abbreviated as BFC(+), I(2)BFC(+), and Et(2)BFC(+)) were determined by means of the spin-lattice relaxation times of the protons, taking into account the local magnetic field fluctuation caused by the electron hopping between the two ferrocene units. We also determined the ET rates of a mixed-valence diferrocenylacetylene monocation (DFA(+)) in order to examine the effect of the insertion of an acetylene bridge between the two ferrocene units. The insertion of the bridge decreased the ET rate, while the effect of substitution on the cyclopentadienyl rings on the rate was minor. The observed rates for each mixed-valence monocation in various solvents did not correlate with the reorganization energies, but we did find a significant contribution of the solvent dynamics. The observed rates were considerably higher than those expected on the basis of the Sumi-Marcus-Nalder model in which the solvents were regarded as dielectric continua. The slope of the logarithm plot of the pre-exponential factors in various solvents for each mixed-valence monocation versus the inverse of the longitudinal dielectric relaxation times of the solvents was significantly smaller than unity, and the slope for DFA(+) was larger than those for BFC(+), I(2)BFC(+), and Et(2)BFC(+). These results were ascribed to a partial contribution of the dielectric friction to the dynamics along the solvent coordinate; the extent of the contribution decreased with a reduction in the ET distance. For the dynamics along the solvent coordinate of the ET reactions in methanol, the observed rates indicated an important contribution by the minor dielectric relaxation components with faster relaxation times, rather than the major component with an extraordinarily long relaxation time.

  16. Structural and dynamical control of the reaction rate in protein electron transfer

    Science.gov (United States)

    Balabin, Ilya A.

    Electron transfer (ET) reactions in proteins are key steps in many vital bioenergetic processes, and the reaction rate is known to be highly sensitive to the protein structure in some cases. For most bioenergetic reactions, as described by the Fermi Golden rule, the rate is proportional to a product of the average square of the effective electronic donor to acceptor coupling and a Franck-Condon factor, which accounts for the nuclear control of the energy gap. The nuclear factor is reasonably well described in Marcus theory and its modifications, and this work is focused on the mechanisms that control the effective coupling. About ten years ago, the Pathways model described for the first time how protein environment may control the effective coupling. In this work, a novel theoretical approach is developed to explore the mechanisms of structural and dynamical control beyond the qualitative level of the Pathways model. In Chapter 1, the assumptions of the Pathways model, its limitations and effects of the structure and the electronic Hamiltonian are investigated for model chain-like bridges using the Dyson's equations. In Chapter II, the framework to explore the sensitivity of the effective coupling to quality of the electronic Hamiltonian, the interference among the dominant pathways and the bridge dynamics is presented. This analysis employs the Green's function technique and includes combined molecular dynamics and electronic structure calculations. Finally, in Chapter III, this framework is tested on the bacterial photosynthetic reaction center, and the mechanisms of the structural and dynamical control for different ET steps are discussed.

  17. Density functional theory study of the structural, electronic, lattice dynamical, and thermodynamic properties of Li4SiO4 and its capability for CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua; Parlinski, K.

    2011-01-01

    The structural, electronic, lattice dynamical, optical, thermodynamic, and CO{sub 2} capture properties of monoclinic and triclinic phases of Li{sub 4}SiO{sub 4} are investigated by combining density functional theory with phonon lattice dynamics calculations. We found that these two phases have some similarities in their bulk and thermodynamic properties. The calculated bulk modulus and the cohesive energies of these two phases are close to each other. Although both of them are insulators, the monoclinic phase of Li{sub 4}SiO{sub 4} has a direct band gap of 5.24 eV while the triclinic Li{sub 4}SiO{sub 4} phase has an indirect band gap of 4.98 eV. In both phases of Li{sub 4}SiO{sub 4}, the s orbital of O mainly contributes to the lower-energy second valence band (VB{sub 2}) and the p orbitals contribute to the fist valence band (VB{sub 1}) and the conduction bands (CBs). The s orbital of Si mainly contributes to the lower portions of the VB1 and VB{sub 2}, and Si p orbitals mainly contribute to the higher portions of the VB{sub 1} and VB{sub 2}. The s and p orbitals of Li contribute to both VBs and to CBs, and Li p orbitals have a higher contribution than the Li s orbital. There is possibly a phonon soft mode existing in triclinic {gamma}-Li{sub 4}SiO{sub 4}; in the monoclinic Li{sub 4}SiO{sub 4}, there are three phonon soft modes, which correspond to the one type of Li disordered over a few sites. Their LO-TO splitting indicates that both phases of Li{sub 4}SiO{sub 4} are polar anisotropic materials. The calculated infrared absorption spectra for LO and TO modes are different for these two phases of Li{sub 4}SiO{sub 4}. The calculated relationships of the chemical potential versus temperature and CO{sub 2} pressure for reaction of Li{sub 4}SiO{sub 4} with CO{sub 2} shows that Li{sub 4}SiO{sub 4} could be a good candidate for a high-temperature CO{sub 2} sorbent while used for postcombustion capture technology.

  18. Direct Measurement of the Flip-Flop Rate of Electron Spins in the Solid State

    Science.gov (United States)

    Dikarov, Ekaterina; Zgadzai, Oleg; Artzi, Yaron; Blank, Aharon

    2016-10-01

    Electron spins in solids have a central role in many current and future spin-based devices, ranging from sensitive sensors to quantum computers. Many of these apparatuses rely on the formation of well-defined spin structures (e.g., a 2D array) with controlled and well-characterized spin-spin interactions. While being essential for device operation, these interactions can also result in undesirable effects, such as decoherence. Arguably, the most important pure quantum interaction that causes decoherence is known as the "flip-flop" process, where two interacting spins interchange their quantum state. Currently, for electron spins, the rate of this process can only be estimated theoretically, or measured indirectly, under limiting assumptions and approximations, via spin-relaxation data. This work experimentally demonstrates how the flip-flop rate can be directly and accurately measured by examining spin-diffusion processes in the solid state for physically fixed spins. Under such terms, diffusion can occur only through this flip-flop-mediated quantum-state exchange and not via actual spatial motion. Our approach is implemented on two types of samples, phosphorus-doped 28Si and nitrogen vacancies in diamond, both of which are significantly relevant to quantum sensors and information processing. However, while the results for the former sample are conclusive and reveal a flip-flop rate of approximately 12.3 Hz, for the latter sample only an upper limit of approximately 0.2 Hz for this rate can be estimated.

  19. Matched comparison of GP and consultant rating of electronic discharge summaries.

    Science.gov (United States)

    Stainkey, Lesley; Pain, Tilley; McNichol, Margaret; Hack, John; Roberts, Lynden

    2010-01-01

    Queensland Health is implementing a state-wide system to electronically generate and distribute discharge summaries. Previously, general practitioners (GPs) have indicated that the quality of the discharge summary does not support clinical handover. While the electronic system will address some issues (e.g. legibility and timeliness), the quality of the discharge summary content is predominantly independent of method of generation. As discharge summaries are usually generated by interns, we proposed that improvement in the quality of the summary may be achieved through education. This project aimed to compare the perceptions of hospital-based consultant educators and recipient GPs regarding discharge summary content and quality. The discharge summary and audit tool were sent to the recipient GP (n=134) and a hospital consultant (n=14) for satisfaction rating, using a 5- point Likert scale for questions relating to diagnosis, the listing of clinical management, medication, pathology, investigations, and recommendations to GP. Sampling was performed by selecting up to 10 discharge summaries completed by each first-year intern (n=36) in 2009, during the second, third and fourth rotations at the Townsville Hospital until a total of 403 was reached. Matched responses were compared using the Kappa statistic. The response rate was 93% (n=375) and 63% (n=254) for consultants and GPs respectively. Results from this study demonstrated that GPs were more satisfied with discharge summaries than were consultants. An anomaly occurred in three questions where, despite the majority of GPs rating satisfied or very satisfied, a small but proportionally greater number of GPs were very dissatisfied when compared with consultants. Poor or fair agreement between GPs and consultants was demonstrated in medications, pathology results, investigations and recommendations to GP, with GPs rating higher satisfaction in all questions. Lower consultant satisfaction ratings compared with GP

  20. Diagnostic for a high-repetition rate electron photo-gun and first measurements

    Science.gov (United States)

    Filippetto, D.; Doolittle, L.; Huang, G.; Norum, E.; Portmann, G.; Qian, H.; Sannibale, F.

    2015-05-01

    The APEX electron source at LBNL combines the high-repetition-rate with the high beam brightness typical of photoguns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment, opening the doors of the high average power to brightness-hungry applications as X-Ray FELs, MHz ultrafast electron diffraction etc.. As first step, a complete characterization of the beam parameters is foreseen at the Gun beam energy of 750 keV. Diagnostics for low and high current measurements have been installed and tested, and measurements of cathode lifetime and thermal emittance in a RF environment with mA current performed. The recent installation of a double slit system, a deflecting cavity and a high precision spectrometer, allow the exploration of the full 6D phase space. Here we discuss the present layout of the machine and future upgrades, showing the latest results at low and high repetition rate, together with the tools and techniques used.