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Sample records for primarily spin-dependent interactions

  1. Spin dependence of the antinucleon-nucleon interaction

    NASA Astrophysics Data System (ADS)

    Haidenbauer, Johann

    2011-05-01

    The status of our present knowledge on the antinucleon-nucleon interaction at low and medium energies is discussed. Special emphasis is put on aspects related to its spin dependence which are relevant for experiments planned by the PAX collaboration. Predictions for the spin-dependent bar pp cross sections σ1 and σ2 are presented, utilizing bar NN potential models developed by the Jülich group, and compared to results based on the amplitudes of the Nijmegen partial-wave analysis.

  2. Dynamics of Interacting Fermions in Spin-Dependent Potentials

    NASA Astrophysics Data System (ADS)

    Koller, Andrew P.; Wall, Michael L.; Mundinger, Josh; Rey, Ana Maria

    2016-11-01

    Recent experiments with dilute trapped Fermi gases observed that weak interactions can drastically modify spin transport dynamics and give rise to robust collective effects including global demagnetization, macroscopic spin waves, spin segregation, and spin self-rephasing. In this Letter, we develop a framework for studying the dynamics of weakly interacting fermionic gases following a spin-dependent change of the trapping potential which illuminates the interplay between spin, motion, Fermi statistics, and interactions. The key idea is the projection of the state of the system onto a set of lattice spin models defined on the single-particle mode space. Collective phenomena, including the global spreading of quantum correlations in real space, arise as a consequence of the long-ranged character of the spin model couplings. This approach achieves good agreement with prior measurements and suggests a number of directions for future experiments.

  3. Dynamics of Interacting Fermions in Spin-Dependent Potentials.

    PubMed

    Koller, Andrew P; Wall, Michael L; Mundinger, Josh; Rey, Ana Maria

    2016-11-04

    Recent experiments with dilute trapped Fermi gases observed that weak interactions can drastically modify spin transport dynamics and give rise to robust collective effects including global demagnetization, macroscopic spin waves, spin segregation, and spin self-rephasing. In this Letter, we develop a framework for studying the dynamics of weakly interacting fermionic gases following a spin-dependent change of the trapping potential which illuminates the interplay between spin, motion, Fermi statistics, and interactions. The key idea is the projection of the state of the system onto a set of lattice spin models defined on the single-particle mode space. Collective phenomena, including the global spreading of quantum correlations in real space, arise as a consequence of the long-ranged character of the spin model couplings. This approach achieves good agreement with prior measurements and suggests a number of directions for future experiments.

  4. Search for exotic spin-dependent interactions with a spin-exchange relaxation-free magnetometer

    DOE PAGES

    Chu, Pinghan; Kim, Young Jin; Savukov, Igor Mykhaylovich

    2016-08-15

    We propose a novel experimental approach to explore exotic spin-dependent interactions using a spin-exchange relaxation-free (SERF) magnetometer, the most sensitive noncryogenic magnetic-field sensor. This approach studies the interactions between optically polarized electron spins located inside a vapor cell of the SERF magnetometer and unpolarized or polarized particles of external solid-state objects. The coupling of spin-dependent interactions to the polarized electron spins of the magnetometer induces the tilt of the electron spins, which can be detected with high sensitivity by a probe laser beam similarly as an external magnetic field. Lastly, we estimate that by moving unpolarized or polarized objects nextmore » to the SERF Rb vapor cell, the experimental limit to the spin-dependent interactions can be significantly improved over existing experiments, and new limits on the coupling strengths can be set in the interaction range below 10–2 m.« less

  5. Search for exotic spin-dependent interactions with a spin-exchange relaxation-free magnetometer

    SciTech Connect

    Chu, Pinghan; Kim, Young Jin; Savukov, Igor Mykhaylovich

    2016-08-15

    We propose a novel experimental approach to explore exotic spin-dependent interactions using a spin-exchange relaxation-free (SERF) magnetometer, the most sensitive noncryogenic magnetic-field sensor. This approach studies the interactions between optically polarized electron spins located inside a vapor cell of the SERF magnetometer and unpolarized or polarized particles of external solid-state objects. The coupling of spin-dependent interactions to the polarized electron spins of the magnetometer induces the tilt of the electron spins, which can be detected with high sensitivity by a probe laser beam similarly as an external magnetic field. Lastly, we estimate that by moving unpolarized or polarized objects next to the SERF Rb vapor cell, the experimental limit to the spin-dependent interactions can be significantly improved over existing experiments, and new limits on the coupling strengths can be set in the interaction range below 10–2 m.

  6. Search for exotic spin-dependent interactions with a spin-exchange relaxation-free magnetometer

    SciTech Connect

    Chu, Pinghan; Kim, Young Jin; Savukov, Igor Mykhaylovich

    2016-08-15

    We propose a novel experimental approach to explore exotic spin-dependent interactions using a spin-exchange relaxation-free (SERF) magnetometer, the most sensitive noncryogenic magnetic-field sensor. This approach studies the interactions between optically polarized electron spins located inside a vapor cell of the SERF magnetometer and unpolarized or polarized particles of external solid-state objects. The coupling of spin-dependent interactions to the polarized electron spins of the magnetometer induces the tilt of the electron spins, which can be detected with high sensitivity by a probe laser beam similarly as an external magnetic field. Lastly, we estimate that by moving unpolarized or polarized objects next to the SERF Rb vapor cell, the experimental limit to the spin-dependent interactions can be significantly improved over existing experiments, and new limits on the coupling strengths can be set in the interaction range below 10–2 m.

  7. Role of spin dependent f- d interaction (Hund coupling) in mixed-valence phenomena

    NASA Astrophysics Data System (ADS)

    Ghosh, N. K.; Mukherjee, P.

    2016-06-01

    The effect of spin dependent f- d interaction (Hund coupling) in mixed-valence phenomena has been investigated within Falicov-Kimball model extended by the spin interaction. Calculations have been performed both at zero and at finite temperatures using exact diagonalization method. It is observed that spin dependent f- d interaction (1) shifts the d-level energy and increases the width of valence transition, (2) increases disorder in the system, (3) causes both single peak and double peak structures to appear in specific heat curves, (4) increases the growth of antiferromagnetic correlations.

  8. Disordered spin dependent interactions in a spinor (S=1) Bose gas: A percolation analysis

    NASA Astrophysics Data System (ADS)

    Nabi, Sk. Noor; Basu, Saurabh

    2016-05-01

    We study the effect of disorder in the spin dependent interaction of a spinor Bose Hubbard model. We apply mean field theory and observe the presence of Bose glass phase by computing the superfluid order parameter and compressibility. The extent of different types of phase is computed via a percolation analysis for phase diagram corresponding to antiferromagnetic interactions.

  9. Disordered spin dependent interactions in a spinor (S=1) Bose gas: A percolation analysis

    SciTech Connect

    Nabi, Sk. Noor; Basu, Saurabh

    2016-05-23

    We study the effect of disorder in the spin dependent interaction of a spinor Bose Hubbard model. We apply mean field theory and observe the presence of Bose glass phase by computing the superfluid order parameter and compressibility. The extent of different types of phase is computed via a percolation analysis for phase diagram corresponding to antiferromagnetic interactions.

  10. Femtosecond Spin Current Pulses Generated by the Nonthermal Spin-Dependent Seebeck Effect and Interacting with Ferromagnets in Spin Valves

    NASA Astrophysics Data System (ADS)

    Alekhin, Alexandr; Razdolski, Ilya; Ilin, Nikita; Meyburg, Jan P.; Diesing, Detlef; Roddatis, Vladimir; Rungger, Ivan; Stamenova, Maria; Sanvito, Stefano; Bovensiepen, Uwe; Melnikov, Alexey

    2017-07-01

    Using the sensitivity of optical second harmonic generation to currents, we demonstrate the generation of 250-fs long spin current pulses in Fe /Au /Fe /MgO (001 ) spin valves. The temporal profile of these pulses indicates ballistic transport of hot electrons across a sub-100 nm Au layer. The pulse duration is primarily determined by the thermalization time of laser-excited hot carriers in Fe. Considering the calculated spin-dependent Fe /Au interface transmittance we conclude that a nonthermal spin-dependent Seebeck effect is responsible for the generation of ultrashort spin current pulses. The demonstrated rotation of spin polarization of hot electrons upon interaction with noncollinear magnetization at Au /Fe interfaces holds high potential for future spintronic devices.

  11. Femtosecond Spin Current Pulses Generated by the Nonthermal Spin-Dependent Seebeck Effect and Interacting with Ferromagnets in Spin Valves.

    PubMed

    Alekhin, Alexandr; Razdolski, Ilya; Ilin, Nikita; Meyburg, Jan P; Diesing, Detlef; Roddatis, Vladimir; Rungger, Ivan; Stamenova, Maria; Sanvito, Stefano; Bovensiepen, Uwe; Melnikov, Alexey

    2017-07-07

    Using the sensitivity of optical second harmonic generation to currents, we demonstrate the generation of 250-fs long spin current pulses in Fe/Au/Fe/MgO(001) spin valves. The temporal profile of these pulses indicates ballistic transport of hot electrons across a sub-100 nm Au layer. The pulse duration is primarily determined by the thermalization time of laser-excited hot carriers in Fe. Considering the calculated spin-dependent Fe/Au interface transmittance we conclude that a nonthermal spin-dependent Seebeck effect is responsible for the generation of ultrashort spin current pulses. The demonstrated rotation of spin polarization of hot electrons upon interaction with noncollinear magnetization at Au/Fe interfaces holds high potential for future spintronic devices.

  12. Constraints on exotic spin-dependent interactions between electrons from helium fine-structure spectroscopy

    NASA Astrophysics Data System (ADS)

    Ficek, Filip; Kimball, Derek F. Jackson; Kozlov, Mikhail G.; Leefer, Nathan; Pustelny, Szymon; Budker, Dmitry

    2017-03-01

    Agreement between theoretical calculations of atomic structure and spectroscopic measurements is used to constrain possible contribution of exotic spin-dependent interactions between electrons to the energy differences between states in helium-4. In particular, constraints on dipole-dipole interactions associated with the exchange of pseudoscalar bosons (such as axions or axion-like particles) with masses 10-2≲m ≲104eV are improved by a factor of ˜100 . The first atomic-scale constraints on several exotic velocity-dependent dipole-dipole interactions are established as well.

  13. Generalized spin-dependent WIMP-nucleus interactions and the DAMA modulation effect

    SciTech Connect

    Scopel, Stefano; Yoon, Kook-Hyun; Yoon, Jong-Hyun E-mail: koreasds@naver.com

    2015-07-01

    Guided by non-relativistic Effective Field Theory (EFT) we classify the most general spin-dependent interactions between a fermionic Weakly Interacting Massive Particle (WIMP) and nuclei, and within this class of models we discuss the viability of an interpretation of the DAMA modulation result in terms of a signal from WIMP elastic scatterings using a halo-independent approach. We find that, although several relativistic EFT's can lead to a spin-dependent cross section, in some cases with an explicit, non-negligible dependence on the WIMP incoming velocity, three main scenarios can be singled out in the non-relativistic limit which approximately encompass them all, and that only differ by their dependence on the transferred momentum. For two of them compatibility between DAMA and other constraints is possible for a WIMP mass below 30 GeV, but only for a WIMP velocity distribution in the halo of our Galaxy which departs from a Maxwellian. This is achieved by combining a suppression of the WIMP effective coupling to neutrons (to evade constraints from xenon and germanium detectors) to an explicit quadratic or quartic dependence of the cross section on the transferred momentum (that leads to a relative enhancement of the expected rate off sodium in DAMA compared to that off fluorine in droplet detectors and bubble chambers). For larger WIMP masses the same scenarios are excluded by scatterings off iodine in COUPP.

  14. Generalized spin-dependent WIMP-nucleus interactions and the DAMA modulation effect

    NASA Astrophysics Data System (ADS)

    Scopel, Stefano; Yoon, Kook-Hyun; Yoon, Jong-Hyun

    2015-07-01

    Guided by non-relativistic Effective Field Theory (EFT) we classify the most general spin-dependent interactions between a fermionic Weakly Interacting Massive Particle (WIMP) and nuclei, and within this class of models we discuss the viability of an interpretation of the DAMA modulation result in terms of a signal from WIMP elastic scatterings using a halo-independent approach. We find that, although several relativistic EFT's can lead to a spin-dependent cross section, in some cases with an explicit, non-negligible dependence on the WIMP incoming velocity, three main scenarios can be singled out in the non-relativistic limit which approximately encompass them all, and that only differ by their dependence on the transferred momentum. For two of them compatibility between DAMA and other constraints is possible for a WIMP mass below 30 GeV, but only for a WIMP velocity distribution in the halo of our Galaxy which departs from a Maxwellian. This is achieved by combining a suppression of the WIMP effective coupling to neutrons (to evade constraints from xenon and germanium detectors) to an explicit quadratic or quartic dependence of the cross section on the transferred momentum (that leads to a relative enhancement of the expected rate off sodium in DAMA compared to that off fluorine in droplet detectors and bubble chambers). For larger WIMP masses the same scenarios are excluded by scatterings off iodine in COUPP.

  15. Spin-independent interferences and spin-dependent interactions with scalar dark matter

    NASA Astrophysics Data System (ADS)

    Martinez, R.; Ochoa, F.

    2016-05-01

    We explore mechanisms of interferences under which the spin-independent interaction in the scattering of scalar dark matter with nucleus is suppressed in relation to the spin-dependent one. We offer a detailed derivation of the nuclear amplitudes based on the interactions with quarks in the framework of a nonuniversal U(1)' extension of the standard model. By assuming a range of parameters compatible with collider searches, electroweak observables and dark matter abundance, we find scenarios for destructive interferences with and without isospin symmetry. The model reveals solutions with mutually interfering scalar particles, canceling the effective spin-independent coupling with only scalar interactions, which requires an extra Higgs boson with mass M H > 125 GeV. The model also possesses scenarios with only vector interactions through two neutral gauge bosons, Z and Z', which do not exhibit interference effects. Due to the nonuniversality of the U(1)' symmetry, we distinguish two family structures of the quark sector with different numerical predictions. In one case, we obtain cross sections that pass all the Xenon-based detector experiments. In the other case, limits from LUX experiment enclose an exclusion region for dark matter between 9 and 800 GeV. We examine a third scenario with isospin-violating couplings where interferences between scalar and vector boson exchanges cancel the scattering. We provide solutions where interactions with Xenon-based detectors is suppressed for light dark matter, below 6 GeV, while interactions with Germanium- and Silicon-based detectors exhibit solutions up to the regions of interest for positive signals reported by CoGeNT and CDMS-Si experiments, and compatible with the observed DM relic density for DM mass in the range 8 .3-10 GeV. Spin-dependent interactions become the dominant source of scattering around the interference regions, where Maxwellian speed distribution is considered.

  16. A dual-isotope rubidium magnetometer for probing anomalous spin-dependent interactions of the proton

    NASA Astrophysics Data System (ADS)

    Lacey, Ian; Jacome, L. R.; Chan, Lok Fai; Peregrina, Rodrigo; Delcheva, Delyana; Kimball, Derek

    2010-03-01

    We report progress in our development of a dual-isotope rubidium magnetometer to be used to search for anomalous spin-dependent interactions of the proton, in particular a long-range coupling between proton spins and the mass of the Earth. The valence electron dominates magnetic interactions and serves as a precise co-magnetometer for the nuclei in a simultaneous measurement of Rb-85 and Rb-87 spin precession frequencies, enabling accurate subtraction of magnetic perturbations. Both Rb nuclei have valence protons, but in Rb-87 the proton spin is parallel to the nuclear spin and magnetic moment while for Rb-85 the proton spin is anti-parallel to the nuclear spin and magnetic moment. Thus anomalous interactions of the proton spin produce a differential shift between the Rb spin-precession frequencies, whereas many sources of systematic error produce common-mode shifts of the spin-precession frequencies which can be controlled through auxiliary measurements. The majority of recent searches for similar effects limit anomalous couplings of either the neutron or electron spin, so the proposed experiments search a parameter space to some degree, depending on the theoretical model, orthogonal to that constrained by previous experiments.

  17. Reevaluation of spin-dependent WIMP-proton interactions as an explanation of the DAMA data

    NASA Astrophysics Data System (ADS)

    Del Nobile, Eugenio; Gelmini, Graciela B.; Georgescu, Andreea; Huh, Ji-Haeng

    2015-08-01

    We reexamine the interpretation of the annual modulation signal observed by the DAMA experiment as due to WIMPs with a spin-dependent coupling mostly to protons. We consider both axial-vector and pseudo-scalar couplings, and elastic as well as endothermic and exothermic inelastic scattering. We conclude that the DAMA signal is in strong tension with null results of other direct detection experiments, particularly PICASSO and KIMS.

  18. Reevaluation of spin-dependent WIMP-proton interactions as an explanation of the DAMA data

    SciTech Connect

    Nobile, Eugenio Del; Gelmini, Graciela B.; Georgescu, Andreea; Huh, Ji-Haeng

    2015-08-25

    We reexamine the interpretation of the annual modulation signal observed by the DAMA experiment as due to WIMPs with a spin-dependent coupling mostly to protons. We consider both axial-vector and pseudo-scalar couplings, and elastic as well as endothermic and exothermic inelastic scattering. We conclude that the DAMA signal is in strong tension with null results of other direct detection experiments, particularly PICASSO and KIMS.

  19. Reevaluation of spin-dependent WIMP-proton interactions as an explanation of the DAMA data

    SciTech Connect

    Nobile, Eugenio Del; Gelmini, Graciela B.; Georgescu, Andreea; Huh, Ji-Haeng E-mail: gelmini@physics.ucla.edu E-mail: jhhuh@physics.ucla.edu

    2015-08-01

    We reexamine the interpretation of the annual modulation signal observed by the DAMA experiment as due to WIMPs with a spin-dependent coupling mostly to protons. We consider both axial-vector and pseudo-scalar couplings, and elastic as well as endothermic and exothermic inelastic scattering. We conclude that the DAMA signal is in strong tension with null results of other direct detection experiments, particularly PICASSO and KIMS.

  20. Implications of the recently discovered 208Pb(1+, Ex=5.845 MeV) state for the spin-dependent nuclear interaction

    NASA Astrophysics Data System (ADS)

    Toki, H.; Bertsch, G. F.; Cha, D.

    1983-09-01

    Measurements on the newly discovered 1+ state at Ex=5.845 MeV in 208Pb provide an opportunity to examine the spin dependence in the nuclear effective Hamiltonian. The data require a somewhat weaker spin-orbit splitting than given by conventional Hamiltonians. The isoscalar spin-dependent residual interaction, which was poorly determined by previous data, is found to be much weaker than the isovector spin-dependent interaction, as predicted by Brueckner theory. NUCLEAR STRUCTURE Simple shell model, spin parameters in the Hamiltonian for 208Pb.

  1. Spin-dependent electron-phonon interaction in SmFeAsO by low-temperature Raman spectroscopy.

    PubMed

    Zhang, L; Guan, P F; Feng, D L; Chen, X H; Xie, S S; Chen, M W

    2010-11-03

    The interplay between spin dynamics and lattice vibration has been suggested as an important part of the puzzle of high-temperature superconductivity. Here, we report the strong interaction between spin fluctuation and phonon in SmFeAsO, a parent compound of the iron arsenide family of superconductors, revealed by low-temperature Raman spectroscopy. Anomalous zone-boundary-phonon Raman scattering from spin superstructure was observed at temperatures below the antiferromagnetic ordering point, which offers compelling evidence on spin-dependent electron-phonon coupling in pnictides.

  2. Improved limits on spin-dependent WIMP-proton interactions from a two liter CF3I bubble chamber.

    PubMed

    Behnke, E; Behnke, J; Brice, S J; Broemmelsiek, D; Collar, J I; Cooper, P S; Crisler, M; Dahl, C E; Fustin, D; Hall, J; Hinnefeld, J H; Hu, M; Levine, I; Ramberg, E; Shepherd, T; Sonnenschein, A; Szydagis, M

    2011-01-14

    Data from the operation of a bubble chamber filled with 3.5 kg of CF3I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic emission than single nuclear recoils, leading to an efficient background discrimination. Three dark matter candidate events were observed during an effective exposure of 28.1  kg  day, consistent with a neutron background. This observation provides strong direct detection constraints on weakly interacting massive particle (WIMP)-proton spin-dependent scattering for WIMP masses >20  GeV/c2.

  3. Spin-dependent Seebeck effect in Aharonov-Bohm rings with Rashba and Dresselhaus spin-orbit interactions

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Li, Yunyun; Zhou, Jun; Nakayama, Tsuneyoshi; Li, Baowen

    2016-06-01

    We theoretically investigate the spin-dependent Seebeck effect in an Aharonov-Bohm mesoscopic ring in the presence of both Rashba and Dresselhaus spin-orbit interactions under magnetic flux perpendicular to the ring. We apply the Green's function method to calculate the spin Seebeck coefficient employing the tight-binding Hamiltonian. It is found that the spin Seebeck coefficient is proportional to the slope of the energy-dependent transmission coefficients. We study the strong dependence of spin Seebeck coefficient on the Fermi energy, magnetic flux, strength of spin-orbit coupling, and temperature. Maximum spin Seebeck coefficients can be obtained when the strengths of Rashba and Dresselhaus spin-orbit couplings are slightly different. The spin Seebeck coefficient can be reduced by increasing temperature and disorder.

  4. Constraints on spin-dependent exotic interactions between electrons at the nanometer scale

    NASA Astrophysics Data System (ADS)

    Luo, Pengshun; Ding, Jihua; Wang, Jianbo; Ren, Xiaofang

    2017-09-01

    New laboratory constraints are obtained on exotic interactions between electrons through pseudoscalar or pseudovector coupling by analyzing a recent measurement of the magnetic dipole-dipole interaction between two iron atoms at the nanometer scale. The analysis imposes the strongest bounds on the pseudovector coupling constant (gAe)2/4 π ℏc between electrons for exchange bosons heavier than 1 eV. Even with the counterpart of electron-positron interaction considered by assuming C P T invariance, the constraints are still the most stringent for bosons in the mass range from 1 eV to 20 eV. The constraints on the pseudoscalar coupling constant (gpe)2/4 π ℏc are only stronger than the limits derived from the trapped-strontium-ion experiment for exchange bosons heavier than 0.14 eV. Furthermore, a new experiment for more stringent constraints is proposed by measuring the interaction between one iron atom and multiple Holmium atoms.

  5. Spin-dependent thermoelectric effect and spin battery mechanism in triple quantum dots with Rashba spin-orbital interaction

    NASA Astrophysics Data System (ADS)

    Xu, Wei-Ping; Zhang, Yu-Ying; Wang, Qiang; Nie, Yi-Hang

    2016-11-01

    We have studied spin-dependent thermoelectric transport through parallel triple quantum dots with Rashba spin-orbital interaction (RSOI) embedded in an Aharonov-Bohm interferometer connected symmetrically to leads using nonequilibrium Green’s function method in the linear response regime. Under the appropriate configuration of magnetic flux phase and RSOI phase, the spin figure of merit can be enhanced and is even larger than the charge figure of merit. In particular, the charge and spin thermopowers as functions of both the magnetic flux phase and the RSOI phase present quadruple-peak structures in the contour graphs. For some specific configuration of the two phases, the device can provide a mechanism that converts heat into a spin voltage when the charge thermopower vanishes while the spin thermopower is not zero, which is useful in realizing the thermal spin battery and inducing a pure spin current in the device. Project supported by the National Natural Science Foundation of China (Grant Nos. 11274208 and 11447170).

  6. Spin-dependent effects in high-order above-threshold ionization: spin-orbit interaction and exchange effects

    NASA Astrophysics Data System (ADS)

    Milošević, D. B.

    2017-08-01

    Spin-dependent effects in atomic processes can be caused by the spin-orbit interaction or/and by the requirement that the wave function of identical electrons is antisymmetric. Such effects are usually neglected in strong-field physics. We show two examples, supported by theoretical results and numerical calculations, in which these effects are important. The first one is based on strong-field ionization of Xe atoms by a bicircular field. The corresponding momentum distribution of spin-polarized electrons emitted in the above-threshold ionization process exhibits wavelength-dependent fast oscillations. For longer wavelengths and small electron emission angle there is a wide photoelectron kinetic energy region in which the spin asymmetry parameter changes continuously from large positive to large negative values. In addition, the emission time of such electrons in high-order above-threshold ionization is determined on the attosecond time scale. The second process considered is high-order above-threshold ionization of excited Li+ ions. We have found that in this case, even in the absence of spin-orbit coupling, the photoelectron momentum distribution strongly depends on the initial spin state. In the singlet state we have characteristic minima, which are caused by the destructive interference of the direct and exchange rescattering amplitudes. Such minima are absent in the triplet state.

  7. On the importance of direct detection combined limits for spin independent and spin dependent dark matter interactions

    NASA Astrophysics Data System (ADS)

    Marcos, Cristina; Peiró, Miguel; Robles, Sandra

    2016-03-01

    In this work we show how the inclusion of dark matter (DM) direct detection upper bounds in a theoretically consistent manner can affect the allowed parameter space of a DM model. Traditionally, the limits from DM direct detection experiments on the elastic scattering cross section of DM particles as a function of their mass are extracted under simplifying assumptions. Relaxing the assumptions related to the DM particle nature, such as the neutron to proton ratio of the interactions, or the possibility of having similar contributions from the spin independent (SI) and spin dependent (SD) interactions can vary significantly the upper limits. Furthermore, it is known that astrophysical and nuclear uncertainties can also affect the upper bounds. To exemplify the impact of properly including all these factors, we have analysed two well motivated and popular DM scenarios: neutralinos in the NMSSM and a Z' portal with Dirac DM. We have found that the allowed parameter space of these models is subject to important variations when one includes both the SI and SD interactions at the same time, realistic neutron to proton ratios, as well as using different self-consistent speed distributions corresponding to popular DM halo density profiles, and distinct SD structure functions. Finally, we provide all the necessary information to include the upper bounds of SuperCDMS and LUX taking into account all these subtleties in the investigation of any particle physics model. The data for each experiment and example codes are available at this site http://goo.gl/1CDFYi, and their use is detailed in the appendices of this work.

  8. Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment.

    PubMed

    Akerib, D S; Araújo, H M; Bai, X; Bailey, A J; Balajthy, J; Beltrame, P; Bernard, E P; Bernstein, A; Biesiadzinski, T P; Boulton, E M; Bradley, A; Bramante, R; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chapman, J J; Chiller, A A; Chiller, C; Currie, A; Cutter, J E; Davison, T J R; de Viveiros, L; Dobi, A; Dobson, J E Y; Druszkiewicz, E; Edwards, B N; Faham, C H; Fiorucci, S; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C R; Hanhardt, M; Haselschwardt, S J; Hertel, S A; Hogan, D P; Horn, M; Huang, D Q; Ignarra, C M; Ihm, M; Jacobsen, R G; Ji, W; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, N A; Lee, C; Lenardo, B G; Lesko, K T; Lindote, A; Lopes, M I; Malling, D C; Manalaysay, A; Mannino, R L; Marzioni, M F; McKinsey, D N; Mei, D-M; Mock, J; Moongweluwan, M; Morad, J A; Murphy, A St J; Nehrkorn, C; Nelson, H N; Neves, F; O'Sullivan, K; Oliver-Mallory, K C; Ott, R A; Palladino, K J; Pangilinan, M; Pease, E K; Phelps, P; Reichhart, L; Rhyne, C; Shaw, S; Shutt, T A; Silva, C; Solovov, V N; Sorensen, P; Stephenson, S; Sumner, T J; Szydagis, M; Taylor, D J; Taylor, W; Tennyson, B P; Terman, P A; Tiedt, D R; To, W H; Tripathi, M; Tvrznikova, L; Uvarov, S; Verbus, J R; Webb, R C; White, J T; Whitis, T J; Witherell, M S; Wolfs, F L H; Yazdani, K; Young, S K; Zhang, C

    2016-04-22

    We present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4×10^{4}  kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=9.4×10^{-41}  cm^{2} (σ_{p}=2.9×10^{-39}  cm^{2}) at 33  GeV/c^{2}. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

  9. Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment

    NASA Astrophysics Data System (ADS)

    Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bradley, A.; Bramante, R.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; de Viveiros, L.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Ott, R. A.; Palladino, K. J.; Pangilinan, M.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Yazdani, K.; Young, S. K.; Zhang, C.; LUX Collaboration

    2016-04-01

    We present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4 ×104 kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn=9.4 ×10-41 cm2 (σp=2.9 ×10-39 cm2 ) at 33 GeV /c2 . The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

  10. Results on the spin-dependent scattering of weakly interacting massive particles on nucleons from the Run 3 Data of the LUX Experiment

    DOE PAGES

    Akerib, D. S.

    2016-04-20

    Here, we present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4 × 104 kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn = 9.4 × 10–41 cm2 (σp = 2.9 × 10–39 cm2) at 33 GeV/c2. Themore » spin-dependent WIMP-neutron limit is the most sensitive constraint to date.« less

  11. Zero-field detection of spin dependent recombination with direct observation of electron nuclear hyperfine interactions in the absence of an oscillating electromagnetic field

    NASA Astrophysics Data System (ADS)

    Cochrane, C. J.; Lenahan, P. M.

    2012-12-01

    Electrically detected magnetic resonance (EDMR) involves the electron paramagnetic resonance (EPR) study of spin dependent transport mechanisms such as spin dependent tunneling and spin dependent recombination (SDR) in solid state electronics. Conventional EPR measurements generally require strong static magnetic fields, typically 3 kG or greater, and high frequency oscillating electromagnetic fields, typically 9 GHz or higher. In this study, we directly demonstrate that, in the absence of the oscillating electromagnetic field, a very large SDR response (≈1%) can be detected at zero magnetic field with associated hyperfine interactions at extremely low magnetic fields in a silicon carbide (SiC) diode at room temperature. The zero-field SDR (ZFSDR) response that we detect is unexpected in the conventional detection scheme of SDR via EDMR. We believe that our observations provide fundamental physical understanding of other recently reported zero-field phenomena such as singlet triplet mixing in double quantum dots and low-field giant magnetoresistance in organic semiconductors. Our work provides an unambiguous demonstration that the zero-field phenomenon we observe involves SDR. Measurements reported herein indicate that extremely useful low-field SDR and ZFSDR results can be acquired simply and inexpensively in systems of technological importance. This work also suggests the potential use of this new physics in applications including absolute magnetometry with self-calibration, spin based memories, quantum computation, and inexpensive low-field EDMR spectrometers for wafer/probing stations.

  12. Improved Limits on Spin-Dependent WIMP-Proton Interactions from a Two Liter CF$_3$I Bubble Chamber

    SciTech Connect

    Behnke, E.; Behnke, J.; Brice, S.J.; Broemmelsiek, D.; Collar, J.I.; Cooper, P.S.; Crisler, M.; Dahl, C.E.; Fustin, D.; Hall, J.; Hinnefeld, J.H.; /Indiana U., South Bend /Fermilab /Indiana U., South Bend /Fermilab /Indiana U., South Bend /Fermilab

    2010-08-01

    Data from the operation of a bubble chamber filled with 3.5 kg of CF{sub 3}I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic emission than single nuclear recoils, leading to an efficient background discrimination. Three dark matter candidate events were observed during an effective exposure of 28.1 kg-day, consistent with a neutron background. This observation provides the strongest direct detection constraint to date on WIMP-proton spin-dependent scattering for WIMP masses > 20 GeV/c{sup 2}.

  13. Improved Limits on Spin-Dependent WIMP-Proton Interactions from a Two Liter CF{sub 3}I Bubble Chamber

    SciTech Connect

    Behnke, E.; Behnke, J.; Hinnefeld, J. H.; Levine, I.; Shepherd, T.; Brice, S. J.; Broemmelsiek, D.; Cooper, P. S.; Crisler, M.; Hall, J.; Hu, M.; Ramberg, E.; Sonnenschein, A.; Collar, J. I.; Dahl, C. E.; Fustin, D.; Szydagis, M.

    2011-01-14

    Data from the operation of a bubble chamber filled with 3.5 kg of CF{sub 3}I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic emission than single nuclear recoils, leading to an efficient background discrimination. Three dark matter candidate events were observed during an effective exposure of 28.1 kg day, consistent with a neutron background. This observation provides strong direct detection constraints on weakly interacting massive particle (WIMP)-proton spin-dependent scattering for WIMP masses >20 GeV/c{sup 2}.

  14. Spin-Dependent Weakly-Interacting-Massive-Particle-Nucleon Cross Section Limits from First Data of PandaX-II Experiment

    NASA Astrophysics Data System (ADS)

    Fu, Changbo; Cui, Xiangyi; Zhou, Xiaopeng; Chen, Xun; Chen, Yunhua; Fang, Deqing; Giboni, Karl; Giuliani, Franco; Han, Ke; Huang, Xingtao; Ji, Xiangdong; Ju, Yonglin; Lei, Siao; Li, Shaoli; Liu, Huaxuan; Liu, Jianglai; Ma, Yugang; Mao, Yajun; Ren, Xiangxiang; Tan, Andi; Wang, Hongwei; Wang, Jiming; Wang, Meng; Wang, Qiuhong; Wang, Siguang; Wang, Xuming; Wang, Zhou; Wu, Shiyong; Xiao, Mengjiao; Xie, Pengwei; Yan, Binbin; Yang, Yong; Yue, Jianfeng; Zhang, Hongguang; Zhang, Tao; Zhao, Li; Zhou, Ning; PandaX-II Collaboration

    2017-02-01

    New constraints are presented on the spin-dependent weakly-interacting-massive-particle- (WIMP-)nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3 ×104 kg day . Assuming a standard axial-vector spin-dependent WIMP interaction with Xe 129 and Xe 131 nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV /c2 are set in all dark matter direct detection experiments. The minimum upper limit of 4.1 ×10-41 cm2 at 90% confidence level is obtained for a WIMP mass of 40 GeV /c2 . This represents more than a factor of 2 improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

  15. Results on the spin-dependent scattering of weakly interacting massive particles on nucleons from the Run 3 Data of the LUX Experiment

    SciTech Connect

    Akerib, D. S.

    2016-04-20

    Here, we present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4 × 104 kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn = 9.4 × 10–41 cm2p = 2.9 × 10–39 cm2) at 33 GeV/c2. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

  16. Results on the spin-dependent scattering of weakly interacting massive particles on nucleons from the Run 3 Data of the LUX Experiment

    SciTech Connect

    Akerib, D. S.

    2016-04-20

    Here, we present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4 × 104 kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn = 9.4 × 10–41 cm2p = 2.9 × 10–39 cm2) at 33 GeV/c2. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

  17. Effect of super-exchange interaction on ground state magnetic properties of spin-dependent Falicov-Kimball model on a triangular lattice

    SciTech Connect

    Kumar, Sant Maitra, Tulika; Singh, Ishwar; Yadav, Umesh K.

    2015-06-24

    Ground state magnetic properties are studied by incorporating the super-exchange interaction (J{sub se}) in the spin-dependent Falicov-Kimball model (FKM) between localized (f-) electrons on a triangular lattice for half filled case. Numerical diagonalization and Monte-Carlo simulation are used to study the ground state magnetic properties. We have found that the magnetic moment of (d-) and (f-) electrons strongly depend on the value of Hund’s exchange (J), super-exchange interaction (J{sub se}) and also depends on the number of (d-) electrons (N{sub d}). The ground state changes from antiferromagnetic (AFM) to ferromagnetic (FM) state as we decrease (N{sub d}). Also the density of d electrons at each site depends on the value of J and J{sub se}.

  18. Effect of super-exchange interaction on ground state magnetic properties of spin-dependent Falicov-Kimball model on a triangular lattice

    NASA Astrophysics Data System (ADS)

    Kumar, Sant; Yadav, Umesh K.; Maitra, Tulika; Singh, Ishwar

    2015-06-01

    Ground state magnetic properties are studied by incorporating the super-exchange interaction (Jse) in the spin-dependent Falicov-Kimball model (FKM) between localized (f-) electrons on a triangular lattice for half filled case. Numerical diagonalization and Monte-Carlo simulation are used to study the ground state magnetic properties. We have found that the magnetic moment of (d-) and (f-) electrons strongly depend on the value of Hund's exchange (J), super-exchange interaction (Jse) and also depends on the number of (d-) electrons (Nd). The ground state changes from antiferromagnetic (AFM) to ferromagnetic (FM) state as we decrease (Nd). Also the density of d electrons at each site depends on the value of J and Jse.

  19. Observation of Spin-Dependent Charge Symmetry Breaking in ΛN Interaction: Gamma-Ray Spectroscopy of _{Λ}^{4}He.

    PubMed

    Yamamoto, T O; Agnello, M; Akazawa, Y; Amano, N; Aoki, K; Botta, E; Chiga, N; Ekawa, H; Evtoukhovitch, P; Feliciello, A; Fujita, M; Gogami, T; Hasegawa, S; Hayakawa, S H; Hayakawa, T; Honda, R; Hosomi, K; Hwang, S H; Ichige, N; Ichikawa, Y; Ikeda, M; Imai, K; Ishimoto, S; Kanatsuki, S; Kim, M H; Kim, S H; Kinbara, S; Koike, T; Lee, J Y; Marcello, S; Miwa, K; Moon, T; Nagae, T; Nagao, S; Nakada, Y; Nakagawa, M; Ogura, Y; Sakaguchi, A; Sako, H; Sasaki, Y; Sato, S; Shiozaki, T; Shirotori, K; Sugimura, H; Suto, S; Suzuki, S; Takahashi, T; Tamura, H; Tanabe, K; Tanida, K; Tsamalaidze, Z; Ukai, M; Yamamoto, Y; Yang, S B

    2015-11-27

    The energy spacing between the spin-doublet bound state of _{Λ}^{4}He(1^{+},0^{+}) was determined to be 1406±2±2  keV, by measuring γ rays for the 1^{+}→0^{+} transition with a high efficiency germanium detector array in coincidence with the ^{4}He(K^{-},π^{-})_{Λ}^{4}He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus _{Λ}^{4}H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in ΛN interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the 0^{+} ground state but is vanishingly small in the 1^{+} excited state, demonstrating that the ΛN CSB interaction has spin dependence.

  20. Short-range, spin-dependent interactions of electrons: a sensitive probe for exotic pseudo-Goldstone bosons

    NASA Astrophysics Data System (ADS)

    Terrano, William; Adelberger, Eric; Lee, John; Heckel, Blayne

    2016-03-01

    We used a torsion pendulum and rotating attractor with 20-pole electron-spin distributions to probe dipole-dipole interactions mediated by exotic pseudo-Goldstone bosons with mbc2 <= 500 μ eV and coupling strengths up to 14 orders of magnitude weaker than electromagnetism. Our 95% confidence result indicates that any hidden global symmetry involving electrons must have a symmetry-breaking scale F >= 70 TeV, the highest reached in any laboratory experiment. We used an attractor with a 20-pole unpolarized mass distribution to improve laboratory bounds on CP -violating monopole-dipole forces with 1 . 5 μ eV

  1. Spin-dependent transport through a chiral molecule in the presence of spin-orbit interaction and nonunitary effects

    NASA Astrophysics Data System (ADS)

    Matityahu, Shlomi; Utsumi, Yasuhiro; Aharony, Amnon; Entin-Wohlman, Ora; Balseiro, Carlos A.

    2016-02-01

    Recent experiments have demonstrated the efficacy of chiral helically shaped molecules in polarizing the scattered electron spin, an effect termed chiral-induced spin selectivity. Here we solve a simple tight-binding model for electron transport through a single helical molecule, with spin-orbit interactions on the bonds along the helix. Quantum interference is introduced via additional electron hopping between neighboring sites in the direction of the helix axis. When the helix is connected to two one-dimensional single-mode leads, time-reversal symmetry prevents spin polarization of the outgoing electrons. One possible way to retrieve such a polarization is to allow leakage of electrons from the helix to the environment, via additional outgoing leads. Technically, the leakage generates complex site self-energies, which break unitarity. As a result, the electron waves in the helix become evanescent, with different decay lengths for different spin polarizations, yielding a net spin polarization of the outgoing electrons, which increases with the length of the helix (as observed experimentally). A maximal polarization can be measured at a finite angle away from the helix axis.

  2. Tunable spin-dependent Andreev reflection in a four-terminal Aharonov-Bohm interferometer with coherent indirect coupling and Rashba spin-orbit interaction

    PubMed Central

    2012-01-01

    Using the nonequilibrium Green’s function method, we theoretically study the Andreev reflection(AR) in a four-terminal Aharonov-Bohm interferometer containing a coupled double quantum dot with the Rashba spin-orbit interaction (RSOI) and the coherent indirect coupling via two ferromagnetic leads. When two ferromagnetic electrodes are in the parallel configuration, the spin-up conductance is equal to the spin-down conductance due to the absence of the RSOI. However, for the antiparallel alignment, the spin-polarized AR occurs resulting from the crossed AR (CAR) and the RSOI. The effects of the coherent indirect coupling, RSOI, and magnetic flux on the Andreev-reflected tunneling magnetoresistance are analyzed at length. The spin-related current is calculated, and a distinct swap effect emerges. Furthermore, the pure spin current can be generated due to the CAR when two ferromagnets become two half metals. It is found that the strong RSOI and the large indirect coupling are in favor of the CAR and the production of the strong spin current. The properties of the spin-related current are tunable in terms of the external parameters. Our results offer new ways to manipulate the spin-dependent transport. PMID:23228047

  3. Tunable spin-dependent Andreev reflection in a four-terminal Aharonov-Bohm interferometer with coherent indirect coupling and Rashba spin-orbit interaction.

    PubMed

    Bai, Long; Zhang, Rong; Duan, Chen-Long

    2012-12-10

    : Using the nonequilibrium Green's function method, we theoretically study the Andreev reflection(AR) in a four-terminal Aharonov-Bohm interferometer containing a coupled double quantum dot with the Rashba spin-orbit interaction (RSOI) and the coherent indirect coupling via two ferromagnetic leads. When two ferromagnetic electrodes are in the parallel configuration, the spin-up conductance is equal to the spin-down conductance due to the absence of the RSOI. However, for the antiparallel alignment, the spin-polarized AR occurs resulting from the crossed AR (CAR) and the RSOI. The effects of the coherent indirect coupling, RSOI, and magnetic flux on the Andreev-reflected tunneling magnetoresistance are analyzed at length. The spin-related current is calculated, and a distinct swap effect emerges. Furthermore, the pure spin current can be generated due to the CAR when two ferromagnets become two half metals. It is found that the strong RSOI and the large indirect coupling are in favor of the CAR and the production of the strong spin current. The properties of the spin-related current are tunable in terms of the external parameters. Our results offer new ways to manipulate the spin-dependent transport.

  4. Inner-shell ionization of rotating linear molecules in the presence of spin-dependent interactions: Entanglement between a photoelectron and an auger electron

    NASA Astrophysics Data System (ADS)

    Ghosh, R.; Chandra, N.; Parida, S.

    2009-03-01

    This paper reports results of a theoretical study of angle- and spin-resolved photo-Auger electron coincident spectroscopy in the form of entanglement between these two particles emitted from a linear molecule. First, we develop an expression for a density matrix needed for studying spin-entanglement between a photoelectron and an Auger electron. In order to properly represent the molecular symmetries, nuclear rotation, and the spin-dependent interactions (SDIs), we have used symmetry adapted wavefunctions in Hund’s coupling scheme (a) for all the species participating in this two-step process. This expression shows that spin-entanglement in a photo-Auger electron pair in the presence of SDIs very strongly depends upon, among other things, polarization of the ionizing radia- tion, directions of motion and of spin polarization of two ejected electrons, and the dynamics of photoionization and of Auger decay. We have applied this expression, as an example, to a generic linear molecule in its J0, M0 = 0 state. This model calculation clearly brings out the salient features of the spin-entanglement of a photo-Auger electron pair in the presence of the SDIs.

  5. Spin-dependent optics with metasurfaces

    NASA Astrophysics Data System (ADS)

    Xiao, Shiyi; Wang, Jiarong; Liu, Fu; Zhang, Shuang; Yin, Xiaobo; Li, Jensen

    2017-01-01

    Optical spin-Hall effect (OSHE) is a spin-dependent transportation phenomenon of light as an analogy to its counterpart in condensed matter physics. Although being predicted and observed for decades, this effect has recently attracted enormous interests due to the development of metamaterials and metasurfaces, which can provide us tailor-made control of the light-matter interaction and spin-orbit interaction. In parallel to the developments of OSHE, metasurface gives us opportunities to manipulate OSHE in achieving a stronger response, a higher efficiency, a higher resolution, or more degrees of freedom in controlling the wave front. Here, we give an overview of the OSHE based on metasurface-enabled geometric phases in different kinds of configurational spaces and their applications on spin-dependent beam steering, focusing, holograms, structured light generation, and detection. These developments mark the beginning of a new era of spin-enabled optics for future optical components.

  6. Geometry of simple molecules: nonbonded interactions, not bonding orbitals, and primarily determine observed geometries.

    PubMed

    See, R F; Dutoi, A D; McConnell, K W; Naylor, R M

    2001-03-28

    The forces responsible for the observed geometries of the YX(3) (Y = N or P; X = H, F, or Cl) molecules were studied through ab initio computations at the HF-SCF/6-31G level. The calculated molecular orbitals were grouped as contributing primarily to (a) the covalent bonds, (b) the terminal atom nonbonding electrons (for X = F or Cl), and (c) the central atom nonbonding electrons. This grouping was accomplished through 3-D plotting and an atomic population analysis of the molecular orbitals. The molecules were then moved through a X-Y-X angular range from 90 degrees to 119 degrees, in four or five degree increments. Single-point calculations were done at each increment, so as to quantify the energy changes in the molecular orbital groups as a function of geometry. These calculations show that the nonbonding electrons are much more sensitive to geometry change than are the bonding orbitals, particularly in the trihalide compounds. The molecular orbitals representing the nonbonding electrons on the terminal atoms (both valence and core electrons) contribute to the spreading forces, as they favor a wider X-Y-X angle. The contracting forces, which favor a smaller X-Y-X angle, consist of the orbitals comprising the nonbonding electrons on the central atom (again, both valence and core electrons). The observed geometry is seen as the balance point between these two sets of forces. A simple interaction-distance model of spreading and contracting forces supports this hypothesis. Highly linear trends are obtained for both the nitrogen trihalides (R(2) = 0.981) and phosphorus trihalides (R(2) = 0.992) when the opposing forces are plotted against each other. These results suggest that a revision of the popular conceptual models (hybridization and VSEPR) of molecular geometry might be appropriate.

  7. Search for primarily non-interacting decay modes of the upsilon

    SciTech Connect

    Leffler, J.S.

    1986-03-01

    The hadronic transition UPSILON(2S) ..-->.. ..pi../sup 0/..pi../sup 0/UPSILON(1S) is utilized to search for the reactions: UPSILON(1S) ..-->.. non-interacting particles and UPSILON(1S) ..-->.. ..gamma.. + non-interacting particles. 44 pb/sup -1/ of UPSILON(2S) data were taken by the Crystal Ball detector at the DORIS II storage ring in order to perform this study. An upper limit of BR(UPSILON ..-->.. Unseen) < 12% (90% C.L.), is obtained via this approach. The second process investigated involved the radiative decay of the Upsilon into non-interacting particles. 57 pb/sup -1/ of UPSILON(2S) data was available for this study. An upper limit on the branching ratio BR(UPSILON ..-->.. ..gamma.. + Unseen) is measured for photon energies in the range 500 MeV < E..gamma.. < M/sub ..gamma..//2. This is the first reported measurement of this type. For the highest energy photons, an upper limit of BR(UPSILON ..-->.. ..gamma.. + Unseen) < 2.3 x 10/sup -3/ (90% C.L.), is obtained. The compact size of the Crystal Ball detector enhances the observable branching ratio for noninteracting particles with short lifetimes such as massive axions. The identification of the recent Darmstadt events with a 1.6 MeV axion is excluded by the present result assuming the minimal Peccei-Quinn model. Limits on the spontaneous supersymmetry breaking mass scale are also derived as a function of gravitino mass.

  8. Spin-dependent WIMP limits from a bubble chamber.

    PubMed

    Behnke, E; Collar, J I; Cooper, P S; Crum, K; Crisler, M; Hu, M; Levine, I; Nakazawa, D; Nguyen, H; Odom, B; Ramberg, E; Rasmussen, J; Riley, N; Sonnenschein, A; Szydagis, M; Tschirhart, R

    2008-02-15

    Bubble chambers were the dominant technology used for particle detection in accelerator experiments for several decades, eventually falling into disuse with the advent of other techniques. We report here on a new application for these devices. We operated an ultraclean, room-temperature bubble chamber containing 1.5 kilograms of superheated CF3I, a target maximally sensitive to spin-dependent and -independent weakly interacting massive particle (WIMP) couplings. An extreme intrinsic insensitivity to the backgrounds that commonly limit direct searches for dark matter was measured in this device under operating conditions leading to the detection of low-energy nuclear recoils like those expected from WIMPs. Improved limits on the spin-dependent WIMP-proton scattering cross section were extracted during our experiments, excluding this type of coupling as a possible explanation for a recent claim of particle dark-matter detection.

  9. Spin-dependent μ → e conversion

    DOE PAGES

    Cirigliano, Vincenzo; Davidson, Sacha; Kuno, Yoshitaka

    2017-05-22

    The experimental sensitivity to μ→e conversion on nuclei is expected to improve by four orders of magnitude in coming years. Here, we consider the impact of μ→e flavour-changing tensor and axial-vector four-fermion operators which couple to the spin of nucleons. Such operators, which have not previously been considered, contribute to μ→e conversion in three ways: in nuclei with spin they mediate a spin-dependent transition; in all nuclei they contribute to the coherent (A2-enhanced) spin-independent conversion via finite recoil effects and via loop mixing with dipole, scalar, and vector operators. Furthermore, we estimate the spin-dependent rate in Aluminium (the target ofmore » the upcoming COMET and Mu2e experiments), show that the loop effects give the greatest sensitivity to tensor and axial-vector operators involving first-generation quarks, and discuss the complementarity of the spin-dependent and independent contributions to μ→e conversion.« less

  10. Spin-dependent μ → e conversion

    NASA Astrophysics Data System (ADS)

    Cirigliano, Vincenzo; Davidson, Sacha; Kuno, Yoshitaka

    2017-08-01

    The experimental sensitivity to μ → e conversion on nuclei is expected to improve by four orders of magnitude in coming years. We consider the impact of μ → e flavour-changing tensor and axial-vector four-fermion operators which couple to the spin of nucleons. Such operators, which have not previously been considered, contribute to μ → e conversion in three ways: in nuclei with spin they mediate a spin-dependent transition; in all nuclei they contribute to the coherent (A2-enhanced) spin-independent conversion via finite recoil effects and via loop mixing with dipole, scalar, and vector operators. We estimate the spin-dependent rate in Aluminium (the target of the upcoming COMET and Mu2e experiments), show that the loop effects give the greatest sensitivity to tensor and axial-vector operators involving first-generation quarks, and discuss the complementarity of the spin-dependent and independent contributions to μ → e conversion.

  11. Spin-dependent shot noise in magnetic graphene superlattice

    NASA Astrophysics Data System (ADS)

    Sattari, Farhad

    2015-10-01

    We study the spin-dependent shot noise properties in magnetic graphene superlattice with Rashba spin-orbit interaction (RSOI). The magnetic field generated by N parallel ferromagnets (FM) deposited on a dielectric layer. We consider two types of magnetic profiles: the FM stripes with magnetization parallel (P) or antiparallel (AP) perpendicular to the graphene. It is found that the shot noise of a spin state can be efficiently controlled by the number of barrier, RSOI strength and magnetic field. In the first case the Fano factor shows a peak with value approximately F = 1/3 for the both spin-up and spin-down electrons at new Dirac-like point. The position of the new Dirac point is robust against the magnetic field and RSOI. In the second case the Fano factor increases by increasing the number of barriers, and plateau of the Fano factor is formed. The results indicate that there is a strong relationship between spin-dependent shot noise and the magnitude of the spin polarization.

  12. Predator effects on a detritus-based food web are primarily mediated by non-trophic interactions.

    PubMed

    Majdi, Nabil; Boiché, Anatole; Traunspurger, Walter; Lecerf, Antoine

    2014-07-01

    Predator effects on ecosystems can extend far beyond their prey and are often not solely lethally transmitted. Change in prey traits in response to predation risk can have important repercussions on community assembly and key ecosystem processes (i.e. trait-mediated indirect effects). In addition, some predators themselves alter habitat structure or nutrient cycling through ecological engineering effects. Tracking these non-trophic pathways is thus an important, yet challenging task to gain a better grasp of the functional role of predators. Multiple lines of evidence suggest that, in detritus-based food webs, non-trophic interactions may prevail over purely trophic interactions in determining predator effects on plant litter decomposition. This hypothesis was tested in a headwater stream by modulating the density of a flatworm predator (Polycelis felina) in enclosures containing oak (Quercus robur) leaf litter exposed to natural colonization by small invertebrates and microbial decomposers. Causal path modelling was used to infer how predator effects propagated through the food web. Flatworms accelerated litter decomposition through positive effects on microbial decomposers. The biomass of prey and non-prey invertebrates was not negatively affected by flatworms, suggesting that net predator effect on litter decomposition was primarily determined by non-trophic interactions. Flatworms enhanced the deposition and retention of fine sediments on leaf surface, thereby improving leaf colonization by invertebrates - most of which having strong affinities with interstitial habitats. This predator-induced improvement of habitat availability was attributed to the sticky nature of the mucus that flatworms secrete in copious amount while foraging. Results of path analyses further indicated that this bottom-up ecological engineering effect was as powerful as the top-down effect on invertebrate prey. Our findings suggest that predators have the potential to affect substantially

  13. Spin dependent electron scattering with the BLAST detector

    NASA Astrophysics Data System (ADS)

    Alarcon, R.

    2005-01-01

    The Bates Larger Acceptance Spectrometer Toroid (BLAST) is a detector designed to study in a comprehensive and precise way the spin dependent electromagnetic response of few-body nuclei. The BLAST scientific program is focussed on the study of these systems in terms of nucleon structure, the ground state few body structure built from the nucleon-nucleon interaction and the nature of the interaction of the virtual photon for Q 2≤1 (GeV/c)2). To accomplish its scientific goals, BLAST utilizes the latest technology available in the form of polarized electron scattering from pure, polarized internal gas targets. The Bates Soung Hall Ring (SHR) delivers longitudinally polarized electrons at the location of the BLAST detector. Measurement are currently underway, and and a brief status report is presented here.

  14. Spin-dependent manipulating of vector beams by tailoring polarization

    PubMed Central

    Zhou, Junxiao; Zhang, Wenshuai; Liu, Yachao; Ke, Yougang; Liu, Yuanyuan; Luo, Hailu; Wen, Shuangchun

    2016-01-01

    We examine the spin-dependent manipulating of vector beams by tailoring the inhomogeneous polarization. The spin-dependent manipulating is attributed to the spin-dependent phase gradient in vector beams, which can be regarded as the intrinsic feature of inhomogeneous polarization. The desired polarization can be obtained by establishing the relationship between the local orientation of polarization and the local orientation of the optical axis of waveplate. We demonstrate that the spin-dependent manipulating with arbitrary intensity patterns can be achieved by tailoring the inhomogeneous polarization. PMID:27677400

  15. Spin-dependent manipulating of vector beams by tailoring polarization.

    PubMed

    Zhou, Junxiao; Zhang, Wenshuai; Liu, Yachao; Ke, Yougang; Liu, Yuanyuan; Luo, Hailu; Wen, Shuangchun

    2016-09-28

    We examine the spin-dependent manipulating of vector beams by tailoring the inhomogeneous polarization. The spin-dependent manipulating is attributed to the spin-dependent phase gradient in vector beams, which can be regarded as the intrinsic feature of inhomogeneous polarization. The desired polarization can be obtained by establishing the relationship between the local orientation of polarization and the local orientation of the optical axis of waveplate. We demonstrate that the spin-dependent manipulating with arbitrary intensity patterns can be achieved by tailoring the inhomogeneous polarization.

  16. Bounds on New Spin Dependent Forces Between Neutrons Using a ^3He / ^129Xe Zeeman Maser

    NASA Astrophysics Data System (ADS)

    Glenday, Alex; Cramer, Claire; Phillips, David F.; Walsworth, Ronald L.

    2008-05-01

    Searches for new spin dependent macroscopic forces place bounds on physics beyond the Standard Model, such as Lorentz symmetry violation and existence of new particles like the axion. We report the first experimental limits on new spin dependent macroscopic forces between neutron spins. We measure the nuclear Zeeman frequencies of a ^3He / ^129Xe maser while we modulate the nuclear spin polarization of ^3He in a separate glass cell. We place limits on the coupling strength of dipole potentials mediated by axion-like particles (gpgp) at the 5.5x10-6 level for interactions at ranges longer than 40 cm.

  17. Spin-dependent parton distributions in the nucleon

    SciTech Connect

    I.C. Cloet; W. Bentz; A.W. Thomas

    2005-04-01

    Spin-dependent quark light-cone momentum distributions are calculated for a nucleon in the nuclear medium. We utilize a modified NJL model where the nucleon is described as a composite quark-diquark state. Scalar and vector mean fields are incorporated in the nuclear medium and these fields couple to the confined quarks in the nucleon. The effect of these fields on the spin-dependent distributions and consequently the axial charges is investigated. Our results for the ''spin-dependent EMC effect'' are also discussed.

  18. Spin-Dependent Transport through Chiral Molecules Studied by Spin-Dependent Electrochemistry

    PubMed Central

    2016-01-01

    Conspectus Molecular spintronics (spin + electronics), which aims to exploit both the spin degree of freedom and the electron charge in molecular devices, has recently received massive attention. Our recent experiments on molecular spintronics employ chiral molecules which have the unexpected property of acting as spin filters, by way of an effect we call “chiral-induced spin selectivity” (CISS). In this Account, we discuss new types of spin-dependent electrochemistry measurements and their use to probe the spin-dependent charge transport properties of nonmagnetic chiral conductive polymers and biomolecules, such as oligopeptides, L/D cysteine, cytochrome c, bacteriorhodopsin (bR), and oligopeptide-CdSe nanoparticles (NPs) hybrid structures. Spin-dependent electrochemical measurements were carried out by employing ferromagnetic electrodes modified with chiral molecules used as the working electrode. Redox probes were used either in solution or when directly attached to the ferromagnetic electrodes. During the electrochemical measurements, the ferromagnetic electrode was magnetized either with its magnetic moment pointing “UP” or “DOWN” using a permanent magnet (H = 0.5 T), placed underneath the chemically modified ferromagnetic electrodes. The spin polarization of the current was found to be in the range of 5–30%, even in the case of small chiral molecules. Chiral films of the l- and d-cysteine tethered with a redox-active dye, toludin blue O, show spin polarizarion that depends on the chirality. Because the nickel electrodes are susceptible to corrosion, we explored the effect of coating them with a thin gold overlayer. The effect of the gold layer on the spin polarization of the electrons ejected from the electrode was investigated. In addition, the role of the structure of the protein on the spin selective transport was also studied as a function of bias voltage and the effect of protein denaturation was revealed. In addition to

  19. Spin-Dependent Transport through Chiral Molecules Studied by Spin-Dependent Electrochemistry.

    PubMed

    Mondal, Prakash Chandra; Fontanesi, Claudio; Waldeck, David H; Naaman, Ron

    2016-11-15

    Molecular spintronics (spin + electronics), which aims to exploit both the spin degree of freedom and the electron charge in molecular devices, has recently received massive attention. Our recent experiments on molecular spintronics employ chiral molecules which have the unexpected property of acting as spin filters, by way of an effect we call "chiral-induced spin selectivity" (CISS). In this Account, we discuss new types of spin-dependent electrochemistry measurements and their use to probe the spin-dependent charge transport properties of nonmagnetic chiral conductive polymers and biomolecules, such as oligopeptides, L/D cysteine, cytochrome c, bacteriorhodopsin (bR), and oligopeptide-CdSe nanoparticles (NPs) hybrid structures. Spin-dependent electrochemical measurements were carried out by employing ferromagnetic electrodes modified with chiral molecules used as the working electrode. Redox probes were used either in solution or when directly attached to the ferromagnetic electrodes. During the electrochemical measurements, the ferromagnetic electrode was magnetized either with its magnetic moment pointing "UP" or "DOWN" using a permanent magnet (H = 0.5 T), placed underneath the chemically modified ferromagnetic electrodes. The spin polarization of the current was found to be in the range of 5-30%, even in the case of small chiral molecules. Chiral films of the l- and d-cysteine tethered with a redox-active dye, toludin blue O, show spin polarizarion that depends on the chirality. Because the nickel electrodes are susceptible to corrosion, we explored the effect of coating them with a thin gold overlayer. The effect of the gold layer on the spin polarization of the electrons ejected from the electrode was investigated. In addition, the role of the structure of the protein on the spin selective transport was also studied as a function of bias voltage and the effect of protein denaturation was revealed. In addition to "dark" measurements, we also describe

  20. Spin-dependent shot noise enhancement in a quantum dot

    NASA Astrophysics Data System (ADS)

    Ubbelohde, Niels; Fricke, Christian; Hohls, Frank; Haug, Rolf J.

    2013-07-01

    The spin-dependent dynamical blockade was investigated in a lateral quantum dot in a magnetic field. Spin-polarized edge channels in the two-dimensional leads and the spatial distribution of Landau orbitals in the dot modulate the tunnel coupling of the quantum dot level spectrum. In a measurement of the electron shot noise we observe a pattern of super-Poissonian noise which is correlated to the spin-dependent competition between different transport channels.

  1. On the spin-dependent sensitivity of XENON100

    NASA Astrophysics Data System (ADS)

    Garny, Mathias; Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan

    2013-03-01

    The latest XENON100 data severely constrain dark matter elastic scattering off nuclei, leading to impressive upper limits on the spin-independent cross section. The main goal of this paper is to stress that the same data set has also an excellent spin-dependent sensitivity, which is of utmost importance in probing dark matter models. We show in particular that the constraints set by XENON100 on the spin-dependent neutron cross section are by far the best at present, whereas the corresponding spin-dependent proton limits lag behind other direct detection results. The effect of nuclear uncertainties on the structure functions of xenon isotopes is analyzed in detail and found to lessen the robustness of the constraints, especially for spin-dependent proton couplings. Notwithstanding, the spin-dependent neutron prospects for XENON1T and DARWIN are very encouraging. We apply our constraints to well-motivated dark matter models and demonstrate that in both mass-degenerate scenarios and the minimal supersymmetric standard model the spin-dependent neutron limits can actually override the spin-independent limits. This opens the possibility of probing additional unexplored regions of the dark matter parameter space with the next generation of ton-scale direct detection experiments.

  2. Improving Limits on Exotic Spin Dependent Long Range Forces using Double Boson Exchange

    NASA Astrophysics Data System (ADS)

    Aldaihan, Sheakha; Snow, William Michael; Krause, Dennis; Long, Joshua

    2016-03-01

    The existence of very light weakly interacting particles that mediate new long range forces has been suggested in many extensions of the Standard Model. Such particles span a length scale between a μm and a few meters and include axions, familons, Majorons,and arions. Parameterizations of forces in this range show that they are composite-dependent, have a Yukawa shape, and have both spin-dependent as well as spin independent components. Very stringent limits on spin-independent couplings exist. For long range spin dependent forces, limits are weaker by 20 orders of magnitude compared to their spin independent analogs. The disparity in the limits raises the question of whether interesting limits on spin dependent couplings can be inferred from spin independent searches for long range forces. We show that this is possible using higher order contributions corresponding to double boson exchange and report the limits placed on spin dependent couplings using this method. We gratefully acknowledge the support of Indiana University and the National Science Foundation. The first author also acknowdges King Abdullah scholarship program.

  3. Spin-dependent scattering in a silicon transistor

    NASA Astrophysics Data System (ADS)

    de Sousa, Rogério; Lo, Cheuk Chi; Bokor, Jeffrey

    2009-07-01

    The scattering of conduction electrons off neutral donors depends sensitively on the relative orientation of their spin states. We present a theory of spin-dependent scattering in the two-dimensional electron gas (2DEG) of field effect transistors. Our theory shows that the scattering mechanism is dominated by virtual transitions to negatively ionized donor levels. This effect translates into a source-drain current that always gets reduced when donor spins are at resonance with a strong microwave field. We propose a model for donor impurities interacting with conduction electrons in a silicon transistor, and compare our explicit numerical calculations to electrically detected magnetic-resonance (EDMR) experiments. Remarkably, we show that EDMR is optimal for donors placed into a sweet spot located at a narrow depth window quite far from the 2DEG interface. This allows significant optimization of spin signal intensity for the minimal number of donors placed into the sweet spot, enabling the development of single spin readout devices. Our theory reveals an interesting dependence on conduction electron-spin polarization pc . As pc increases upon spin injection, the EDMR amplitude first increases as pc2 and then saturates when a polarization threshold pT is reached. These results show that it is possible to use EDMR as an in situ probe of carrier spin polarization in silicon and other materials with weak spin-orbit coupling.

  4. The spin-dependent neutralino-nucleus form factor for {sup 127}I

    SciTech Connect

    Ressell, M.T.; Dean, D.J.

    1996-12-01

    We present the results of detailed shell model calculations of the spin-dependent elastic form factor for the nucleus {sup 127}I. the calculations were performed in extremely large model spaces which adequately describe the configuration mixing in this nucleus. Good agreement between the calculated and experimental values of the magnetic moment are found. Other nuclear observables are also compared to experiment. The dependence of the form factor upon the model space and effective interaction is discussed.

  5. Electric-field effect on the spin-dependent resonance tunneling

    SciTech Connect

    Alekseev, P. S.; Chistyakov, V. M.; Yassievich, I. N.

    2006-12-15

    A theory of spin-dependent resonance tunneling through a double-barrier heterostructure in the presence of an electric field is developed. Spin-orbit interaction is taken into account by introducing the Dresselhaus term into the effective Hamiltonian. The possibility of fabricating the spin detectors and injectors based on a GaAlSb nonmagnetic semiconductor heterostructure controlled by electric field is analyzed.

  6. Manipulating the spin-dependent splitting by geometric Doppler effect.

    PubMed

    Liu, Yachao; Ke, Yougang; Zhou, Junxiao; Luo, Hailu; Wen, Shuangchun

    2015-06-29

    We report the manipulation of spin-dependent splitting by geometric Doppler effect based on dielectric metasurfaces. The extrapolation of rotational Doppler effect from temporal to spatial coordinate gives the phase change when the local optical axes of dielectric metasurfaces are rotating in space. Therefore, the continuous variation of local optical axes in a certain direction will introduce a phase gradient in the same direction at the beam cross section. This is additive to the phase gradient appeared when breaking the rotational symmetry of linearly polarized cylindrical vector beams, which leads to the deflections of different spin components of light, i.e., photonic spin Hall effect. Hence, it is possible to manipulate the spin-dependent splitting by introducing the geometric Doppler effect. Theoretically and experimentally, we show that the magnitude and orientation of the spin-dependent splitting are both tunable when changing the spatial rotation rate of local optical axes and incident polarization.

  7. Spin-dependent thermoelectric effects in graphene-based superconductor junctions

    NASA Astrophysics Data System (ADS)

    Beiranvand, Razieh; Hamzehpour, Hossein

    2017-02-01

    Using the Bogoliubov-de Gennes formalism, we investigate the charge and spin-dependent thermoelectric effects in graphene-based superconductor junctions. The results demonstrate that despite normal-superconductor junctions, there is a temperature-dependent spin thermopower in both the graphene-based ferromagnetic-superconductor and ferromagnetic-Rashba spin-orbit region-superconductor junctions. It is also shown that in the presence of Rashba spin-orbit interaction, the charge and spin-dependent Seebeck coefficients reach their maximum up to 3.5 k B / e and 2.5 k B / e , respectively. Remarkably, these coefficients have a zero-point critical value with respect to the magnetic exchange field and chemical potential. This effect disappears when the Rashba coupling is absent. These results suggest that graphene-based superconductors can be used in spin-caloritronic devices.

  8. Realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect

    SciTech Connect

    Ling, Xiaohui; Yi, Xunong; Zhou, Xinxing; Liu, Yachao; Shu, Weixing; Wen, Shuangchun; Luo, Hailu

    2014-10-13

    We report the realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect. By breaking the rotational symmetry of a cylindrical vector beam, the intrinsic vortex phases that the two spin components of the vector beam carries, which is similar to the geometric Pancharatnam-Berry phase, are no longer continuous in the azimuthal direction, and leads to observation of spin accumulation at the opposite edge of the beam. Due to the inherent nature of the phase and independency of light-matter interaction, the observed photonic spin Hall effect is intrinsic. Modulating the topological charge of the vector beam, the spin-dependent splitting can be enhanced and the direction of spin accumulation is switchable. Our findings may provide a possible route for generation and manipulation of spin-polarized photons, and enables spin-based photonics applications.

  9. Spin dependent scattering and the quark content of nucleons

    SciTech Connect

    Manohar, A.

    1994-10-26

    Recent experiments have begun to probe the detailed spin and flavor structure of hadrons. The status of the g{sub 1} structure function and its implications for the polarized strange quark sea will be discussed, as well as what we hope to learn about hadronic structure from spin dependent measurements that will be carried out over the next few years.

  10. Morphology effects on spin-dependent transport and recombination in polyfluorene thin films

    NASA Astrophysics Data System (ADS)

    Miller, Richards; van Schooten, K. J.; Malissa, H.; Joshi, G.; Jamali, S.; Lupton, J. M.; Boehme, C.

    2016-12-01

    We have studied the role of spin-dependent processes on conductivity in polyfluorene (PFO) thin films by preforming continuous wave (cw) electrically detected magnetic resonance (EDMR) spectroscopy at temperatures between 10 K and room temperature using microwave frequencies between about 1 GHz and 20 GHz, as well as pulsed EDMR at the X band (10 GHz). Variable frequency EDMR allows us to establish the role of spin-orbit coupling in spin-dependent processes whereas pulsed EDMR allows for the observation of coherent spin motion effects. We used PFO for this study in order to allow for the investigation of the effects of microscopic morphological ordering since this material can adopt two distinct intrachain morphologies: an amorphous (glassy) phase, in which monomer units are twisted with respect to each other, and an ordered (β) phase, where all monomers lie within one plane. In thin films of organic light-emitting diodes, the appearance of a particular phase can be controlled by deposition parameters and solvent vapor annealing, and is verified by electroluminescence spectroscopy. Under bipolar charge-carrier injection conditions, we conducted multifrequency cw EDMR, electrically detected Rabi spin-beat experiments, and Hahn echo and inversion-recovery measurements. Coherent echo spectroscopy reveals electrically detected electron-spin-echo envelope modulation due to the coupling of the carrier spins to nearby nuclear spins. Our results demonstrate that, while conformational disorder can influence the observed EDMR signals, including the sign of the current changes on resonance as well as the magnitudes of local hyperfine fields and charge-carrier spin-orbit interactions, it does not qualitatively affect the nature of spin-dependent transitions in this material. In both morphologies, we observe the presence of at least two different spin-dependent recombination processes. At room temperature and 10 K, polaron-pair recombination through weakly spin-spin coupled

  11. Measuring spin-dependent structure functions at CEBAF

    SciTech Connect

    Schaefer, A.

    1994-04-01

    The author analyses whether CEBAF with a 10 GeV beam could contribute significantly to the understanding of spin-dependent deep-inelastic scattering as well as semi-inclusive reactions. The main advantage of CEBAF is the much better attainable statistics, its great disadvantage its comparably low energy, which limits the accessible x-range to about 0.15 to 0.7. Within these constraints CEBAF could provide (1) high precision data which would be very valuable to understand the Q{sup 2} dependence of the spin-dependent structure functions g{sub 1}(x) and G{sub 2}(x) and (2) the by far most precise determination of the third moments of g{sub 1}(x) and g{sub 2}(x) the latter of which the author argues to be related to a fundamental property of the nucleon.

  12. Tunable Spin-Dependent Properties of Zigzag Silicene Nanoribbons

    NASA Astrophysics Data System (ADS)

    Le, Nam B.; Huan, Tran Doan; Woods, Lilia M.

    2014-06-01

    Silicene zigzag nanoribbons are studied using ab initio simulation methods. We find novel structure-property relations influenced by several factors, such as the magnitude of the width, spin polarization, spin-orbit coupling, and extended topological defects. It is obtained that while defect-free silicene nanoribbons experience antiferromagnetic-ferromagnetic transition as a function of the width, all defective nanoribbons are ferromagnets. At the same time, the spin-orbit coupling role is significant as it leads to spin-dependent energy gaps in the electronic structure. The origin of edged spin polarization is also studied in terms of the balance between the exchange correlation and kinetic energy contributions. The uncovered unique spin-dependent properties may be useful for the application of silicene nanoribbons in spintronic applications.

  13. Spin-dependent quantum interference in nonlocal graphene spin valves.

    PubMed

    Guimarães, M H D; Zomer, P J; Vera-Marun, I J; van Wees, B J

    2014-05-14

    Up to date, all spin transport experiments on graphene were done in a semiclassical regime, disregarding quantum transport properties such as phase coherence and interference. Here we show that in a quantum coherent graphene nanostructure the nonlocal voltage is strongly modulated. Using nonlocal measurements, we separate the signal in spin-dependent and spin-independent contributions. We show that the spin-dependent contribution is about 2 orders of magnitude larger than the spin-independent one, when corrected for the finite polarization of the electrodes. The nonlocal spin signal is not only strongly modulated but also changes polarity as a function of the applied gate voltage. By locally tuning the carrier density in the constriction via a side gate electrode we show that the constriction plays a major role in this effect. Our results show the potential of quantum coherent graphene nanostructures for the use in future spintronic devices.

  14. Direct observation of the spin-dependent Peltier effect.

    PubMed

    Flipse, J; Bakker, F L; Slachter, A; Dejene, F K; van Wees, B J

    2012-02-05

    The Peltier coefficient describes the amount of heat that is carried by an electrical current when it passes through a material. When two materials with different Peltier coefficients are placed in contact with one another, the Peltier effect causes a net flow of heat either towards or away from the interface between them. Spintronics describes the transport of electric charge and spin angular momentum by separate spin-up and spin-down channels in a device. The observation that spin-up and spin-down charge transport channels are able to transport heat independently of each other has raised the possibility that spin currents could be used to heat or cool the interface between materials with different spin-dependent Peltier coefficients. Here, we report the direct observation of the heating and cooling of such an interface by a spin current. We demonstrate this spin-dependent Peltier effect in a spin-valve pillar structure that consists of two ferromagnetic layers separated by a non-ferromagnetic metal. Using a three-dimensional finite-element model, we extract spin-dependent Peltier coefficients in the range -0.9 to -1.3 mV for permalloy. The magnetic control of heat flow could prove useful for the cooling of nanoscale electronic components or devices.

  15. Direct observation of the spin-dependent Peltier effect

    NASA Astrophysics Data System (ADS)

    Flipse, J.; Bakker, F. L.; Slachter, A.; Dejene, F. K.; van Wees, B. J.

    2012-03-01

    The Peltier coefficient describes the amount of heat that is carried by an electrical current when it passes through a material. When two materials with different Peltier coefficients are placed in contact with one another, the Peltier effect causes a net flow of heat either towards or away from the interface between them. Spintronics describes the transport of electric charge and spin angular momentum by separate spin-up and spin-down channels in a device. The observation that spin-up and spin-down charge transport channels are able to transport heat independently of each other has raised the possibility that spin currents could be used to heat or cool the interface between materials with different spin-dependent Peltier coefficients. Here, we report the direct observation of the heating and cooling of such an interface by a spin current. We demonstrate this spin-dependent Peltier effect in a spin-valve pillar structure that consists of two ferromagnetic layers separated by a non-ferromagnetic metal. Using a three-dimensional finite-element model, we extract spin-dependent Peltier coefficients in the range -0.9 to -1.3 mV for permalloy. The magnetic control of heat flow could prove useful for the cooling of nanoscale electronic components or devices.

  16. New measurements of spin-dependent n-p cross sections

    SciTech Connect

    Raichle, B. W.; Gould, C. R.; Haase, D. G.; Seely, M. L.; Walston, J. R.; Tornow, W.; Wilburn, W. S.; Penttilae, S. I.; Hoffmann, G. W.

    1999-06-10

    We report on new measurements of the spin-dependent neutron-proton total cross-section differences in longitudinal and transverse geometries ({delta}{sigma}{sub L} and {delta}{sigma}{sub T} respectively) and between 5 and 20 MeV. These transmission experiments involve a polarized neutron beam and polarized proton target. The polarized neutron beam was produced as a secondary beam via charged-particle induced neutron-production reactions. The proton target was cryogenically cooled and dynamically polarized. These data will be used to extract {epsilon}{sub 1}, the phase-shift parameter which characterizes the strength of the tensor interaction at low energy.

  17. Nanoparticles Affect PCR Primarily via Surface Interactions with PCR Components: Using Amino-Modified Silica-Coated Magnetic Nanoparticles as a Main Model.

    PubMed

    Bai, Yalong; Cui, Yan; Paoli, George C; Shi, Chunlei; Wang, Dapeng; Shi, Xianming

    2015-06-24

    Nanomaterials have been widely reported to affect the polymerase chain reaction (PCR). However, many studies in which these effects were observed were not comprehensive, and many of the proposed mechanisms have been primarily speculative. In this work, we used amino-modified silica-coated magnetic nanoparticles (ASMNPs, which can be collected very easily using an external magnetic field) as a model and compared them with gold nanoparticles (AuNPs, which have been studied extensively) to reveal the mechanisms by which nanoparticles affect PCR. We found that nanoparticles affect PCR primarily by binding to PCR components: (1) inhibition, (2) specifity, and (3) efficiency and yield of PCR are impacted. (1) Excess nanomaterials inhibit PCR by adsorbing to DNA polymerase, Mg(2+), oligonucleotide primers, or DNA templates. Nanoparticle surface-active groups are particularly important to this effect. (2, a) Nanomaterials do not inhibit nonspecific amplification products caused by false priming as previously surmised. It was shown that relatively low concentrations of nanoparticles inhibited the amplification of long amplicons, and increasing the amount of nanoparticles inhibited the amplification of short amplicons. This concentration phenomenon appears to be the result of the formation of "joints" upon the adsorption of ASMNPs to DNA templates. (b) Nanomaterials are able to inhibit nonspecific amplification products due to incomplete amplification by preferably adsorbing single-stranded incomplete amplification products. (3) Some types of nanomaterials, such as AuNPs, enhance the efficiency and yield of PCR because these types of nanoparticles can adsorb to single-stranded DNA more strongly than to double-stranded DNA. This behavior assists in the rapid and thorough denaturation of double-stranded DNA templates. Therefore, the interaction between the surface of nanoparticles and PCR components is sufficient to explain most of the effects of nanoparticles on PCR.

  18. Precision measurement of the neutron spin dependent structure functions

    SciTech Connect

    Kolomensky, Y.G.

    1997-02-01

    In experiment E154 at the Stanford Linear Accelerator Center the spin dependent structure function g{sub 1}{sup n} (x, Q{sup 2}) of the neutron was measured by scattering longitudinally polarized 48.3 GeV electrons off a longitudinally polarized {sup 3}He target. The high beam energy allowed the author to extend the kinematic coverage compared to the previous SLAC experiments to 0.014 {le} x {le} 0.7 with an average Q{sup 2} of 5 GeV{sup 2}. The author reports the integral of the spin dependent structure function in the measured range to be {integral}{sub 0.014}{sup 0.7} dx g{sub 1}{sup n}(x, 5 GeV{sup 2}) = {minus}0.036 {+-} 0.004(stat.) {+-} 0.005(syst.). The author observes relatively large values of g{sub 1}{sup n} at low x that call into question the reliability of data extrapolation to x {r_arrow} 0. Such divergent behavior disagrees with predictions of the conventional Regge theory, but is qualitatively explained by perturbative QCD. The author performs a Next-to-Leading Order perturbative QCD analysis of the world data on the nucleon spin dependent structure functions g{sub 1}{sup p} and g{sub 1}{sup n} paying careful attention to the experimental and theoretical uncertainties. Using the parameterizations of the helicity-dependent parton distributions obtained in the analysis, the author evolves the data to Q{sup 2} = 5 GeV{sup 2}, determines the first moments of the polarized structure functions of the proton and neutron, and finds agreement with the Bjorken sum rule.

  19. Spin-dependent tunneling in magnetic tunnel junctions

    NASA Astrophysics Data System (ADS)

    Davis, Albert Hamilton, Jr.

    In this work I present results of a theoretical study of the intrinsic response of ferromagnetic tunnel junctions (MTJ's). The goal of the work has been to understand the underlying physics in order to describe the intrinsic portion of the observed behavior. Specifically, I present a free electron tunneling model which predicts that the magneto-conductance ratio (ΔG/G) or tunneling magneto-resistance (TMR) in high quality MTJs is dominated by the intrinsic response. The model assumes an effective tunneling electronic structure which has been constructed from parameters extracted from first principles calculations and a simple barrier whose effective height and thickness are deduced from the experiments. This model does not utilize the polarization (P) of the density of states (DOS) as an input parameter, but rather calculates the conductance for each spin channel and configuration in order to calculate TMR directly. The process of matching spin-dependent tunneling states with spin-independent barrier states produces a spin-dependent T-matrix which is the main difference between this model and other prevalent models which have been built upon Julliere's model (M. Julliere, Phys. Lett. 54 225, 1975). The effect of bias is handled by increasing the chemical potential on one side of the barrier, and the effect of temperature is included via Fermi smearing and the temperature dependent magnetic band structure. The model predicts that MTJ's are quite sensitive to changes in the magnetic band structure. This explains both the large temperature dependence of TMR and the high sensitivity of MTJ's to magnetic fields. The model strongly supports the assertion that only a portion of the total DOS is relevant to spin-dependent tunneling (SDT) and that the bands which supply the tunneling electrons are essentially Stoner split. I conclude with a consideration of asymmetric TMR and a short first principles study of fcc magnetic alloys which gives some insight into the relative

  20. Exotic Paired States with Anisotropic Spin-Dependent Fermi Surfaces

    SciTech Connect

    Feiguin, Adrian E.; Fisher, Matthew P. A.

    2009-07-10

    We propose a model for realizing exotic paired states in cold Fermi gases by using a spin-dependent optical lattice to engineer mismatched Fermi surfaces for each hyperfine species. The BCS phase diagram shows a stable paired superfluid state with coexisting pockets of momentum space with gapless unpaired carriers, similar to the Sarma state in polarized mixtures, but in our case the system is unpolarized. We propose the possible existence of an exotic 'Cooper-pair Bose-metal' phase, which has a gap for single fermion excitations but gapless and uncondensed 'Cooper-pair' excitations residing on a 'Bose surface' in momentum space.

  1. 3He Spin-Dependent Cross Sections and Sum Rules

    SciTech Connect

    Slifer, Karl; Amaryan, Moscov; Amaryan, Moskov; Auerbach, Leonard; Averett, Todd; Berthot, J.; Bertin, Pierre; Bertozzi, William; Black, Tim; Brash, Edward; Brown, D.; Burtin, Etienne; Calarco, John; Cates, Gordon; Chai, Zhengwei; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Ciofi, Claudio; Cisbani, Evaristo; De Jager, Cornelis; Deur, Alexandre; DiSalvo, R.; Dieterich, Sonja; Djawotho, Pibero; Finn, John; Fissum, Kevin; Fonvieille, Helene; Frullani, Salvatore; Gao, Haiyan; Gao, Juncai; Garibaldi, Franco; Gasparian, Ashot; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Glashausser, Charles; Glockle, W.; Golak, J.; Goldberg, Emma; Gomez, Javier; Gorbenko, Viktor; Hansen, Jens-Ole; Hersman, F.; Holmes, Richard; Huber, Garth; Hughes, Emlyn; Humensky, Thomas; Incerti, Sebastien; Iodice, Mauro; Jensen, S.; Jiang, Xiaodong; Jones, C.; Jones, G.; Jones, Mark; Jutier, Christophe; Kamada, H.; Ketikyan, Armen; Kominis, Ioannis; Korsch, Wolfgang; Kramer, Kevin; Kumar, Krishna; Kumbartzki, Gerfried; Kuss, Michael; Lakuriqi, Enkeleida; Laveissiere, Geraud; LeRose, John; Liang, Meihua; Liyanage, Nilanga; Lolos, George; Malov, Sergey; Marroncle, Jacques; McCormick, Kathy; McKeown, Robert; Meziani, Zein-Eddine; Michaels, Robert; Mitchell, Joseph; Nogga, Andreas; Pace, Emanuele; Papandreou, Zisis; Pavlin, Tina; Petratos, Gerassimos; Pripstein, David; Prout, David; Ransome, Ronald; Roblin, Yves; Rowntree, David; Rvachev, Marat; Sabatie, Franck; Saha, Arunava; Salme, Giovanni; SCOPETTA, S.; Skibinski, R.; Souder, Paul; Saito, Teijiro; Strauch, Steffen; Suleiman, Riad; Takahashi, Kazunori; Todor, Luminita; Tsubota, Hiroaki; Ueno, Hiroaki; Urciuoli, Guido; van der Meer, Rob; Vernin, Pascal; Voskanyan, Hakob; Witala, Henryk; Wojtsekhowski, Bogdan; Xiong, Feng; Xu, Wang; Yang, Jae-Choon; Zhang, Bin; Zolnierczuk, Piotr

    2008-07-01

    We present a measurement of the spin-dependent cross sections for the \\vec{^3He}(\\vec{e},e')X} reaction in the quasielastic and resonance regions at four-momentum transfer 0.1 < Q^2< 0.9 GeV^2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt--Cottingham and extended GDH sum rules for the first time. Impulse approximation and exact three-body Faddeev calculations are also compared to the data in the quasielastic region.

  2. 3He spin-dependent cross sections and sum rules.

    PubMed

    Slifer, K; Amarian, M; Auerbach, L; Averett, T; Berthot, J; Bertin, P; Bertozzi, B; Black, T; Brash, E; Brown, D; Burtin, E; Calarco, J; Cates, G; Chai, Z; Chen, J-P; Choi, Seonho; Chudakov, E; Ciofi Degli Atti, C; Cisbani, E; de Jager, C W; Deur, A; DiSalvo, R; Dieterich, S; Djawotho, P; Finn, M; Fissum, K; Fonvieille, H; Frullani, S; Gao, H; Gao, J; Garibaldi, F; Gasparian, A; Gilad, S; Gilman, R; Glamazdin, A; Glashausser, C; Glöckle, W; Golak, J; Goldberg, E; Gomez, J; Gorbenko, V; Hansen, J-O; Hersman, B; Holmes, R; Huber, G M; Hughes, E; Humensky, B; Incerti, S; Iodice, M; Jensen, S; Jiang, X; Jones, C; Jones, G; Jones, M; Jutier, C; Kamada, H; Ketikyan, A; Kominis, I; Korsch, W; Kramer, K; Kumar, K; Kumbartzki, G; Kuss, M; Lakuriqi, E; Laveissiere, G; Lerose, J J; Liang, M; Liyanage, N; Lolos, G; Malov, S; Marroncle, J; McCormick, K; McKeown, R D; Meziani, Z-E; Michaels, R; Mitchell, J; Nogga, A; Pace, E; Papandreou, Z; Pavlin, T; Petratos, G G; Pripstein, D; Prout, D; Ransome, R; Roblin, Y; Rowntree, D; Rvachev, M; Sabatié, F; Saha, A; Salmè, G; Scopetta, S; Skibiński, R; Souder, P; Saito, T; Strauch, S; Suleiman, R; Takahashi, K; Teijiro, S; Todor, L; Tsubota, H; Ueno, H; Urciuoli, G; Van der Meer, R; Vernin, P; Voskanian, H; Witała, H; Wojtsekhowski, B; Xiong, F; Xu, W; Yang, J-C; Zhang, B; Zolnierczuk, P

    2008-07-11

    We present a measurement of the spin-dependent cross sections for the 3He over -->(e over -->,e')X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1< or =Q2< or =0.9 GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.

  3. Spin-dependent interpretation for possible signals of light dark matter

    SciTech Connect

    Buckley, Matthew R.; Lippincott, W. Hugh

    2013-09-01

    Signals broadly compatible with light (7-10 GeV) dark matter have been reported in three direct detection experiments: CoGeNT, DAMA/LIBRA, and CDMS-II silicon. These possible signals have been interpreted in the context of spin-independent interactions between the target nuclei and dark matter, although there is tension with null results, particularly from xenon-based experiments. In this paper, we demonstrate that the CoGeNT and CDMS-II silicon results are also compatible assuming a spin-dependent neutron interaction, though this is in tension with xenon-based experiments and PICASSO. The tension with the null results from XENON100 and XENON10 is approximately the same as for the spin-independent coupling. All three experimental signals can be made compatible through a combination of spin-dependent interactions with both the proton and neutron, although such a scenario increases the conflict with the null results of other experiments.

  4. Species Specificity of Vaccinia Virus Complement Control Protein for the Bovine Classical Pathway Is Governed Primarily by Direct Interaction of Its Acidic Residues with Factor I.

    PubMed

    Kumar, Jitendra; Yadav, Viveka Nand; Phulera, Swastik; Kamble, Ashish; Gautam, Avneesh Kumar; Panwar, Hemendra Singh; Sahu, Arvind

    2017-10-01

    Poxviruses display species tropism-variola virus is a human-specific virus, while vaccinia virus causes repeated outbreaks in dairy cattle. Consistent with this, variola virus complement regulator SPICE (smallpox inhibitor of complement enzymes) exhibits selectivity in inhibiting the human alternative complement pathway and vaccinia virus complement regulator VCP (vaccinia virus complement control protein) displays selectivity in inhibiting the bovine alternative complement pathway. In the present study, we examined the species specificity of VCP and SPICE for the classical pathway (CP). We observed that VCP is ∼43-fold superior to SPICE in inhibiting bovine CP. Further, functional assays revealed that increased inhibitory activity of VCP for bovine CP is solely due to its enhanced cofactor activity, with no effect on decay of bovine CP C3-convertase. To probe the structural basis of this specificity, we utilized single- and multi-amino-acid substitution mutants wherein 1 or more of the 11 variant VCP residues were substituted in the SPICE template. Examination of these mutants for their ability to inhibit bovine CP revealed that E108, E120, and E144 are primarily responsible for imparting the specificity and contribute to the enhanced cofactor activity of VCP. Binding and functional assays suggested that these residues interact with bovine factor I but not with bovine C4(H2O) (a moiety conformationally similar to C4b). Mapping of these residues onto the modeled structure of bovine C4b-VCP-bovine factor I supported the mutagenesis data. Taken together, our data help explain why the vaccine strain of vaccinia virus was able to gain a foothold in domesticated animals.IMPORTANCE Vaccinia virus was used for smallpox vaccination. The vaccine-derived virus is now circulating and causing outbreaks in dairy cattle in India and Brazil. However, the reason for this tropism is unknown. It is well recognized that the virus is susceptible to neutralization by the complement

  5. Spin-dependent recombination probed through the dielectric polarizability

    PubMed Central

    Bayliss, Sam L.; Greenham, Neil C.; Friend, Richard H.; Bouchiat, Hélène; Chepelianskii, Alexei D

    2015-01-01

    Despite residing in an energetically and structurally disordered landscape, the spin degree of freedom remains a robust quantity in organic semiconductor materials due to the weak coupling of spin and orbital states. This enforces spin-selectivity in recombination processes which plays a crucial role in optoelectronic devices, for example, in the spin-dependent recombination of weakly bound electron-hole pairs, or charge-transfer states, which form in a photovoltaic blend. Here, we implement a detection scheme to probe the spin-selective recombination of these states through changes in their dielectric polarizability under magnetic resonance. Using this technique, we access a regime in which the usual mixing of spin-singlet and spin-triplet states due to hyperfine fields is suppressed by microwave driving. We present a quantitative model for this behaviour which allows us to estimate the spin-dependent recombination rate, and draw parallels with the Majorana–Brossel resonances observed in atomic physics experiments. PMID:26439933

  6. Spin-dependent Peltier effect in 3D topological insulators

    NASA Astrophysics Data System (ADS)

    Sengupta, Parijat; Kubis, Tillmann; Povolotskyi, Michael; Klimeck, Gerhard

    2013-03-01

    The Peltier effect represents the heat carrying capacity of a certain material when current passes through it. When two materials with different Peltier coefficients are placed together, the Peltier effect causes heat to flow either towards or away from the interface between them. This work utilizes the spin-polarized property of 3D topological insulator (TI) surface states to describe the transport of heat through the spin-up and spin-down channels. It has been observed that the spin channels are able to carry heat independently of each other. Spin currents can therefore be employed to supply or extract heat from an interface between materials with spin-dependent Peltier coefficients. The device is composed of a thin film of Bi2Se3 sandwiched between two layers of Bi2Te3. The thin film of Bi2Se3serves both as a normal and topological insulator. It is a normal insulator when its surfaces overlap to produce a finite band-gap. Using an external gate, Bi2Se3 film can be again tuned in to a TI. Sufficiently thick Bi2Te3 always retain TI behavior. Spin-dependent Peltier coefficients are obtained and the spin Nernst effect in TIs is shown by controlling the temperature gradient to convert charge current to spin current.

  7. Large Conductance Switching in a Single-Molecule Device through Room Temperature Spin-Dependent Transport.

    PubMed

    Aragonès, Albert C; Aravena, Daniel; Cerdá, Jorge I; Acís-Castillo, Zulema; Li, Haipeng; Real, José Antonio; Sanz, Fausto; Hihath, Josh; Ruiz, Eliseo; Díez-Pérez, Ismael

    2016-01-13

    Controlling the spin of electrons in nanoscale electronic devices is one of the most promising topics aiming at developing devices with rapid and high density information storage capabilities. The interface magnetism or spinterface resulting from the interaction between a magnetic molecule and a metal surface, or vice versa, has become a key ingredient in creating nanoscale molecular devices with novel functionalities. Here, we present a single-molecule wire that displays large (>10000%) conductance switching by controlling the spin-dependent transport under ambient conditions (room temperature in a liquid cell). The molecular wire is built by trapping individual spin crossover Fe(II) complexes between one Au electrode and one ferromagnetic Ni electrode in an organic liquid medium. Large changes in the single-molecule conductance (>100-fold) are measured when the electrons flow from the Au electrode to either an α-up or a β-down spin-polarized Ni electrode. Our calculations show that the current flowing through such an interface appears to be strongly spin-polarized, thus resulting in the observed switching of the single-molecule wire conductance. The observation of such a high spin-dependent conductance switching in a single-molecule wire opens up a new door for the design and control of spin-polarized transport in nanoscale molecular devices at room temperature.

  8. Forward pd elastic scattering and total spin-dependent pd cross sections at intermediate energies

    SciTech Connect

    Uzikov, Yu. N.; Haidenbauer, J.

    2009-02-15

    Spin-dependent total pd cross sections are considered using the optical theorem. For this aim the full spin dependence of the forward pd elastic scattering amplitude is considered in a model independent way. The single-scattering approximation is used to relate this amplitude to the elementary amplitudes of pp and pn scattering and the deuteron form factor. A formalism allowing to take into account Coulomb-nuclear interference effects in polarized pd cross sections is developed. Numerical calculations for the polarized total pd cross sections are performed at beam energies 20-300 MeV using the NN interaction models developed by the Juelich group. Double-scattering effects are estimated within the Glauber approach and found to be in the order of 10-20%. Existing experimental data on differential pd cross sections are in good agreement with the performed Glauber calculations. It is found that for the used NN models the total longitudinal and transversal pd cross sections are comparable in absolute value to those for pp scattering.

  9. Spin dependent transport and recombination in organic lightemitting diodes

    NASA Astrophysics Data System (ADS)

    Silva, George B.; Nüesch, Frank; Zuppiroli, Libero; Graeff, Carlos F. O.

    2005-08-01

    Electrically Detected Magnetic Resonance (EDMR) was used to study a series of multilayer organic devices based on aluminum (III) 8-hydroxyquinoline (Alq3). These devices were designed to identify the microscopic origin of different spin dependent process, i.e. hopping and exciton formation. For electroluminescent diode the EDMR signal can be decomposed in at least two gaussian components with peak-to-peak linewidth (HPP ) of 1.6 mT and another with 2.0 mT to 3.4 mT. These components are dependent on the applied bias or current used during EDMR measurements. The narrower line was attributed to the exciton precursor cations, while the broad one to the anions. These attributions are supported by the investigation of unipolar diodes, where hopping process related to dication and dianion formation were observed. In this work it is found that the probability of singlet exciton formation during electroluminescency is smaller than 25%.

  10. Mechanisms of Spin-Dependent Heat Generation in Spin Valves

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-Xue; Zhu, Yao-Hui; He, Pei-Song; Li, Bao-He

    2017-06-01

    The extra heat generation in spin transport is usually interpreted in terms of the spin relaxation. By reformulating the heat generation rate, we found alternative current-force pairs without cross effects, which enable us to interpret the product of each pair as a distinct mechanism of heat generation. The results show that the spin-dependent part of the heat generation includes two terms. One of them is proportional to the square of the spin accumulation and arises from the spin relaxation. However, the other is proportional to the square of the spin-accumulation gradient and should be attributed to another mechanism, the spin diffusion. We illustrated the characteristics of the two mechanisms in a typical spin valve with a finite nonmagnetic spacer layer.

  11. Strain-modulation of spin-dependent transport in graphene

    SciTech Connect

    Cao, Zhen-Zhou Hou, Jin; Cheng, Yan-Fu; Li, Guan-Qiang

    2014-10-27

    We investigate strain modulation of the spin-dependent electron transport in a graphene junction using the transfer matrix method. As an analogy to optics, we define the modulation depth in the electron optics domain. Additionally, we discuss the transport properties and show that the modulation depth and the conductance depend on the spin-orbit coupling strength, the strain magnitude, the width of the strained area, and the energy of the incident electron. The conductances of the spin-down and spin-up electrons have opposite and symmetrical variations, which results in the analogous features of their modulation depths. The maximum conditions for both the modulation depth and the electron spin upset rate are also analyzed.

  12. Spin-dependent electron emission from metals in the neutralization of He{sup +} ions

    SciTech Connect

    Alducin, M.; Roesler, M.; Juaristi, J.I.

    2005-08-15

    We calculate the spin-polarization of electrons emitted in the neutralization of He{sup +} ions interacting with metals. All stages of the emission process are included: the spin-dependent perturbation induced by the projectile, the excitation of electrons in Auger neutralization processes, the creation of a cascade of secondaries, and the escape of the electrons through the surface potential barrier. The model allows us to explain in quantitative terms the measured spin-polarization of the yield in the interaction of spin-polarized He{sup +} ions with paramagnetic surfaces, and to disentangle the role played by each of the involved mechanisms. We show that electron-electron scattering processes at the surface determine the spin-polarization of the total yield. High energy emitted electrons are the ones providing direct information on the He{sup +} ion neutralization process and on the electronic properties of the surface.

  13. Theory of time-domain measurement of spin-dependent recombination with pulsed electrically detected magnetic resonance

    NASA Astrophysics Data System (ADS)

    Boehme, Christoph; Lips, Klaus

    2003-12-01

    The theoretical foundations of the time domain measurement of spin-dependent charge carrier recombination by means of pulsed electrically detected magnetic resonance (EDMR) are outlined. Pulsed EDMR is based on the transient measurement of electrical currents in semiconductors after a coherent manipulation of paramagnetic centers with pulsed electron spin resonance (ESR). A model of spin-dependent recombination is introduced combining features of previous models into one general picture that takes influences by spin-relaxation, singlet and triplet recombination as well as spin-spin interactions within recombining charge carrier pairs into account. Based thereon, predictions for excess charge carrier currents after short coherent pulse ESR excitations are made which show that spin coherence in semiconductors can be observed by means of current measurements and hence, microscopic, quantitative information about charge carrier recombination dynamics by means of pulsed EDMR is attainable.

  14. Nanoparticles affect PCR primarily via surface interactions with PCR components: using amino-modified silica-coated magnetic nanoparticles as a main model

    USDA-ARS?s Scientific Manuscript database

    Nanomaterials have been widely reported to affect the polymerase chain reaction (PCR). However, many studies in which these effects were observed were not comprehensive, and many of the proposed mechanisms have been primarily speculative. In this work, we used amino-modified silica-coated magnetic n...

  15. {pi} Phases in Balanced Fermionic Superfluids on Spin-Dependent Optical Lattices

    SciTech Connect

    Zapata, I.; Wunsch, B.; Zinner, N. T.; Demler, E.

    2010-08-27

    We study a balanced two-component system of ultracold fermions in one dimension with attractive interactions and subject to a spin-dependent optical lattice potential of opposite sign for the two components. We find states with different types of modulated pairing order parameters which are conceptually similar to {pi} phases discussed for superconductor-ferromagnet heterostructures. Increasing the lattice depth induces sharp transitions between states of different parity. While the origin of the order parameter oscillations is similar to the Fulde-Ferrel-Larkin-Ovchinnikov phase for paired states with spin imbalance, the current system is intrinsically stable to phase separation. We discuss experimental requirements for creating and probing these novel phases.

  16. The spin-dependent transport of Co-encapsulated Si nanotubes contacted with Cu electrodes

    SciTech Connect

    Guo, Yan-Dong; Yan, Xiao-Hong; Xiao, Yang

    2014-02-10

    Unlike carbon nanotubes, silicon ones are hard to form. However, they could be stabilized by metal-encapsulation. Using first-principles calculations, we investigate the spin-dependent electronic transport of Co-encapsulated Si nanotubes, which are contacted with Cu electrodes. For the finite tubes, as the tube-length increases, the transmission changes from spin-unpolarized to spin-polarized. Further analysis shows that, not only the screening of electrodes on Co's magnetism but also the spin-asymmetric Co-Co interactions are the physical mechanisms. As Cu and Si are the fundamental elements in semiconductor industry, our results may throw light on the development of silicon-based spintronic devices.

  17. New measurements of spin-dependent n-p cross sections

    SciTech Connect

    Raichle, B.W.; Gould, C.R.; Haase, D.G.; Seely, M.L.; Walston, J.R.; Tornow, W.; Wilburn, W.S.; Raichle, B.W.; Gould, C.R.; Haase, D.G.; Seely, M.L.; Walston, J.R.; Tornow, W.; Wilburn, W.S.; Penttilae, S.I.; Hoffmann, G.W.

    1999-06-01

    We report on new measurements of the spin-dependent neutron-proton total cross-section differences in longitudinal and transverse geometries ({Delta}{sigma}{sub L} and {Delta}{sigma}{sub T} respectively) and between 5 and 20 MeV. These transmission experiments involve a polarized neutron beam and polarized proton target. The polarized neutron beam was produced as a secondary beam via charged-particle induced neutron-production reactions. The proton target was cryogenically cooled and dynamically polarized. These data will be used to extract {var_epsilon}{sub 1}, the phase-shift parameter which characterizes the strength of the tensor interaction at low energy. {copyright} {ital 1999 American Institute of Physics.}

  18. Artificial topological models based on a one-dimensional spin-dependent optical lattice

    NASA Astrophysics Data System (ADS)

    Zheng, Zhen; Pu, Han; Zou, Xubo; Guo, Guangcan

    2017-01-01

    Topological matter is a popular topic in both condensed matter and cold-atom research. In the past decades, a variety of models have been identified with fascinating topological features. Some, but not all, of the models can be found in materials. As a fully controllable system, cold atoms trapped in optical lattices provide an ideal platform to simulate and realize these topological models. Here we present a proposal for synthesizing topological models in cold atoms based on a one-dimensional spin-dependent optical lattice potential. In our system, features such as staggered tunneling, staggered Zeeman field, nearest-neighbor interaction, beyond-near-neighbor tunneling, etc. can be readily realized. They underlie the emergence of various topological phases. Our proposal can be realized with current technology and hence has potential applications in quantum simulation of topological matter.

  19. Organic light-emitting devices using spin-dependent processes

    DOEpatents

    Vardeny, Z. Valy; Wohlgenannt, Markus

    2010-03-23

    The maximum luminous efficiency of organic light-emitting materials is increased through spin-dependent processing. The technique is applicable to all electro-luminescent processes in which light is produced by singlet exciton decay, and all devices which use such effects, including LEDs, super-radiant devices, amplified stimulated emission devices, lasers, other optical microcavity devices, electrically pumped optical amplifiers, and phosphorescence (Ph) based light emitting devices. In preferred embodiments, the emissive material is doped with an impurity, or otherwise modified, to increase the spin-lattice relaxation rate (i.e., decrease the spin-lattice time), and hence raise the efficiency of the device. The material may be a polymer, oligomer, small molecule, single crystal, molecular crystal, or fullerene. The impurity is preferably a magnetic or paramagnetic substance. The invention is applicable to IR, UV, and other electromagnetic radiation generation and is thus not limited to the visible region of the spectrum. The methods of the invention may also be combined with other techniques used to improve device performance.

  20. Shape Biased Low Power Spin Dependent Tunneling Magnetic Field Sensors

    NASA Astrophysics Data System (ADS)

    Tondra, Mark; Qian, Zhenghong; Wang, Dexin; Nordman, Cathy; Anderson, John

    2001-10-01

    Spin Dependent Tunneling (SDT) devices are leading candidates for inclusion in a number of Unattended Ground Sensor applications. Continued progress at NVE has pushed their performance to 1OOs of pT I rt. Hz 1 Hz. However, these sensors were designed to use an applied field from an on-chip coil to create an appropriate magnetic sensing configuration. The power required to generate this field (^100mW) is significantly greater than the power budget (^lmW) for a magnetic sensor in an Unattended Ground Sensor (UGS) application. Consequently, a new approach to creating an ideal sensing environment is required. One approach being used at NVE is "shape biasing." This means that the physical layout of the SDT sensing elements is such that the magnetization of the sensing film is correct even when no biasing field is applied. Sensors have been fabricated using this technique and show reasonable promise for UGS applications. Some performance trade-offs exist. The power is easily tinder 1 MW, but the sensitivity is typically lower by a factor of 10. This talk will discuss some of the design details of these sensors as well as their expected ultimate performance.

  1. Time constants of spin-dependent recombination processes

    NASA Astrophysics Data System (ADS)

    Hoehne, Felix; Dreher, Lukas; Suckert, Max; Franke, David P.; Stutzmann, Martin; Brandt, Martin S.

    2013-10-01

    We present experiments to systematically study the time constants of spin-dependent recombination processes in semiconductors using pulsed electrically detected magnetic resonance (EDMR). The combination of time-programmed optical excitation and pulsed spin manipulation allows us to directly measure the recombination time constants of electrons via localized spin pairs and the time constant of spin-pair formation as a function of the optical excitation intensity. Using electron nuclear double resonance, we show that the time constant of spin-pair formation is determined by an electron capture process. Based on these time constants we devise a set of rate equations to calculate the current transient after a resonant microwave pulse and compare the results with experimental data. Finally, we critically discuss the effects of different boxcar integration time intervals typically used to analyze pulsed EDMR experiments on the determination of the time constants. The experiments are performed on phosphorus-doped silicon, where EDMR via spin pairs formed by phosphorus donors and Si/SiO2 interface dangling bond defects is detected.

  2. Spin Dependent Transport in Graphene Nano Ribbon Devices

    NASA Astrophysics Data System (ADS)

    Souma, Satofumi; Ogawa, Matsuto; Yamamoto, Takahiro; Watanabe, Kazuyuki

    2009-03-01

    Graphene is now one of the promising materials for future nanoelectronics. Especially graphene nanoribbon is attracting great attention since it possesses finite bandgap opening depending on the ribbon width and the transport orientation with respect to the graphene lattice. Another interesting property seen in graphene nanoribbon is the appearance of the ``edge-spin'' polarization at the edges of the zigzag-edged graphene nanoribbon. Recently it has been shown that such edge- spin polarization can be electrically controlled to induce the half-metallic band structure in such structures, meaning the electrical controllability of the spin current in such material. Therefore, toward the realization of the graphene nanoribbon spintronics, it is now important to study the spin- dependent transport characteristics in realistic device structure based on zigzag graphene nanoribbon. Here we present our numerical study of spin transport in zigzag-edged graphene nanoribbon transistor structures [1] using spin-density functional tight-binding method. Special attention is paid to the influence of edge roughness and electrostatic doping on the spin polarization and the spin current. [1] S.Souma, M.Ogawa, T.Yamamoto, K.Watanabe, J.Comp. Electron. 7, 390 (2008).

  3. Spin-dependent tunnel junctions with ZrOx barriers

    NASA Astrophysics Data System (ADS)

    Wang, Jianguo; Freitas, P. P.; Snoeck, E.; Wei, P.; Soares, J. C.

    2001-12-01

    Spin-dependent tunnel junctions with crystalline ZrOx barriers were fabricated, with tunnel magnetoresistance (TMR) reaching 20% and a resistance×area product of 24 k Ω μm2, after annealing at 260 °C. Effective barrier height and thickness are 1.6 eV and 10.6 Å, respectively. The ZrOx barriers were fabricated by rf plasma oxidation of a 5 Å thick Zr layer. High-resolution transmission electron microscopy and Rutherford backscattering spectrometry were used to characterize the as-deposited barrier. Both ZrO and ZrO2 phases are present, together with (CoFe)Ox. Upon annealing, the interfacial oxygen moves into the barrier, resulting in an increase of TMR from 2% to 19.2%, an increase of barrier height from 0.3 to 1.6 eV, and a reduction of barrier thickness from 18.5 to 10.5 Å.

  4. Thermodynamic properties of correlated fermions in lattices with spin-dependent disorder

    NASA Astrophysics Data System (ADS)

    Makuch, K.; Skolimowski, J.; Chakraborty, P. B.; Byczuk, K.; Vollhardt, D.

    2013-04-01

    Motivated by the rapidly growing possibilities for experiments with ultracold atoms in optical lattices, we investigate the thermodynamic properties of correlated lattice fermions in the presence of an external spin-dependent random potential. The corresponding model, a Hubbard model with spin-dependent local random potentials, is solved within dynamical mean-field theory. This allows us to present a comprehensive picture of the thermodynamic properties of this system. In particular, we show that for a fixed total number of fermions spin-dependent disorder induces a magnetic polarization. The magnetic response of the polarized system differs from that of a system with conventional disorder.

  5. Precision Measurement of the Spin Dependent Asymmetry in the Threshold Region of {sup 3}He(e,e{prime})

    SciTech Connect

    F. Xiong; Dipangkar Dutta; W. Xu; Bryon Anderson; L. Auberbach; Todd Averett; William Bertozzi; Timothy Black; John Calarco; Larry Cardman; Gorden Cates; Zhengwei Chai; Jian-ping Chen; Seonho Choi; Eugene Chudakov; Steve Churchwell; G.S. Corrado; C. Crawford; Dan Dale; Alexandre Deur; Pibaro Djawotho; Bradley Filippone; Mike Finn; Haiyan Gao; Ron Gilman; Alexander Glamazdin; Charles Glashausser; W. Glockle; J. Golak; Javier Gomez; Victor Gorbenko; Jens-Ole Hansen; F. William Hersman; Douglas W. Higinbotham; Richard Holmes; C.R. Howell; E. Hughes; B. Humensky; Sebastian Incerti; Kees de Jager; J.Steffen Jensen; Xiangdong Jiang; C.E. Jones; Mark Jones; R. Kahl; H. Kamada; A. Kievsky; Ioannis Kominis; Wolfgang Korsch; Kevin Kramer; Gerfried Kumbartzki; Michael Kuss; E. Lakuriqi; Meme Liang; Nilanga Liyanage; John LeRose; Sergey Malov; Dimitri Margaziotis; Jeffrey Martin; Kathy McCormick; Robert McKeown; K. McIlhany; Zein-Eddine Meziani; Robert Michaels; G.W. Miller; E. Pace; T. Pavlin; Gerassimos G. Petratos; R.I. Pomatsalyuk; D. Pripstein; David Prout; Ronald Ransome; Yves Roblin; Marat Rvachev; Arun Saha; G. Salme; M. Schnee; Taeksu Shin; Karl Slifer; Paul Souder; Steffen Strauch; Riad Suleiman; M. Sutter; Bryan Tipton; Luminita Todor; M. Viviani; B. Vlahovic; J. Watson; C.F. Williamson; H. Witala; Bogdan B. Wojtsekhowski; J. Yeh; P. Zolnierczuk

    2001-12-10

    We present the first precision measurement of the spin-dependent asymmetry in the threshold region of {sup 3}He(e,e{prime}) at Q{sup 2}-values of 0.1 and 0.2 (GeV/c){sup 2}. The agreement between the data and non-relativistic Faddeev calculations which include both final-state interactions (FSI) and meson-exchange currents (MEC) effects is very good at Q{sup 2} = 0.1 (GeV/c){sup 2}, while a small discrepancy at Q{sup 2} = 0.2 (GeV/c){sup 2} is observed.

  6. Precision measurement of the spin-dependent asymmetry in the threshold region of 3He(e, e').

    PubMed

    Xiong, F; Dutta, D; Xu, W; Anderson, B; Auberbach, L; Averett, T; Bertozzi, W; Black, T; Calarco, J; Cardman, L; Cates, G D; Chai, Z W; Chen, J P; Choi, S; Chudakov, E; Churchwell, S; Corrado, G S; Crawford, C; Dale, D; Deur, A; Djawotho, P; Filippone, B W; Finn, J M; Gao, H; Gilman, R; Glamazdin, A V; Glashausser, C; Glöckle, W; Golak, J; Gomez, J; Gorbenko, V G; Hansen, J O; Hersman, F W; Higinbotham, D W; Holmes, R; Howell, C R; Hughes, E; Humensky, B; Incerti, S; de Jager, C W; Jensen, J S; Jiang, X; Jones, C E; Jones, M; Kahl, R; Kamada, H; Kievsky, A; Kominis, I; Korsch, W; Kramer, K; Kumbartzki, G; Kuss, M; Lakuriqi, E; Liang, M; Liyanage, N; LeRose, J; Malov, S; Margaziotis, D J; Martin, J W; McCormick, K; McKeown, R D; McIlhany, K; Meziani, Z E; Michaels, R; Miller, G W; Pace, E; Pavlin, T; Petratos, G G; Pomatsalyuk, R I; Pripstein, D; Prout, D; Ransome, R D; Roblin, Y; Rvachev, M; Saha, A; Salmè, G; Schnee, M; Shin, T; Slifer, K; Souder, P A; Strauch, S; Suleiman, R; Sutter, M; Tipton, B; Todor, L; Viviani, M; Vlahovic, B; Watson, J; Williamson, C F; Witała, H; Wojtsekhowski, B; Yeh, J; Zołnierczuk, P

    2001-12-10

    We present the first precision measurement of the spin-dependent asymmetry in the threshold region of 3He(e,e') at Q2 values of 0.1 and 0.2 (GeV/c)2. The agreement between the data and nonrelativistic Faddeev calculations which include both final-state interactions and meson-exchange current effects is very good at Q2 = 0.1 (GeV/c)2, while a small discrepancy at Q2 = 0.2 (GeV/c)2 is observed.

  7. NHE-RF, a Merlin-Interacting Protein, Is Primarily Expressed in Luminal Epithelia, Proliferative Endometrium, and Estrogen Receptor-Positive Breast Carcinomas

    PubMed Central

    Stemmer-Rachamimov, Anat O.; Wiederhold, Thorsten; Nielsen, G. Petur; James, Marianne; Pinney-Michalowski, Denise; Roy, Jennifer E.; Cohen, Wendy A.; Ramesh, Vijaya; Louis, David N.

    2001-01-01

    NHE-RF, a regulatory cofactor for NHE (Na+-H+ exchanger) type 3, interacts with ion transporters and receptors through its PDZ domains and with the MERM proteins (merlin, ezrin, radixin and moesin) via its carboxyl terminus. Thus, NHE-RF may act as a multifunctional adaptor protein and play a role in the assembly of signal transduction complexes, linking ion channels and receptors to the actin cytoskeleton. NHE-RF expression is up-regulated in response to estrogen in estrogen receptor-positive breast carcinoma cell lines, suggesting that it may be involved in estrogen signaling. To further understand NHE-RF function and its possible role in estrogen signaling, we analyzed NHE-RF expression in normal human tissues, including cycling endometrium, and in breast carcinomas, tissues in which estrogen plays an important role in regulating cell growth and proliferation. NHE-RF is expressed in many epithelia, especially in cells specialized in ion transport or absorption, and is often localized to apical (luminal) membranes. NHE-RF expression varies markedly in proliferative versus secretory endometrium, with high expression in proliferative (estrogen-stimulated) endometrium. Furthermore, estrogen receptor status and NHE-RF expression correlate closely in breast carcinoma specimens. These findings support a role for NHE-RF in estrogen signaling. PMID:11141479

  8. Realization of spin-dependent splitting with arbitrary intensity patterns based on all-dielectric metasurfaces

    SciTech Connect

    Ke, Yougang; Liu, Yachao; He, Yongli; Zhou, Junxiao; Luo, Hailu Wen, Shuangchun

    2015-07-27

    We report the realization of spin-dependent splitting with arbitrary intensity patterns based on all-dielectric metasurfaces. Compared with the plasmonic metasurfaces, the all-dielectric metasurface exhibits more high transmission efficiency and conversion efficiency, which makes it possible to achieve the spin-dependent splitting with arbitrary intensity patterns. Our findings suggest a way for generation and manipulation of spin photons, and thereby offer the possibility of developing spin-based nanophotonic applications.

  9. Spin-dependent quantum interference in photoemission process from spin-orbit coupled states.

    PubMed

    Yaji, Koichiro; Kuroda, Kenta; Toyohisa, Sogen; Harasawa, Ayumi; Ishida, Yukiaki; Watanabe, Shuntaro; Chen, Chuangtian; Kobayashi, Katsuyoshi; Komori, Fumio; Shin, Shik

    2017-02-24

    Spin-orbit interaction entangles the orbitals with the different spins. The spin-orbital-entangled states were discovered in surface states of topological insulators. However, the spin-orbital-entanglement is not specialized in the topological surface states. Here, we show the spin-orbital texture in a surface state of Bi(111) by laser-based spin- and angle-resolved photoelectron spectroscopy (laser-SARPES) and describe three-dimensional spin-rotation effect in photoemission resulting from spin-dependent quantum interference. Our model reveals that, in the spin-orbit-coupled systems, the spins pointing to the mutually opposite directions are independently locked to the orbital symmetries. Furthermore, direct detection of coherent spin phenomena by laser-SARPES enables us to clarify the phase of the dipole transition matrix element responsible for the spin direction in photoexcited states. These results permit the tuning of the spin polarization of optically excited electrons in solids with strong spin-orbit interaction.

  10. Spin-dependent quantum interference in photoemission process from spin-orbit coupled states

    PubMed Central

    Yaji, Koichiro; Kuroda, Kenta; Toyohisa, Sogen; Harasawa, Ayumi; Ishida, Yukiaki; Watanabe, Shuntaro; Chen, Chuangtian; Kobayashi, Katsuyoshi; Komori, Fumio; Shin, Shik

    2017-01-01

    Spin–orbit interaction entangles the orbitals with the different spins. The spin–orbital-entangled states were discovered in surface states of topological insulators. However, the spin–orbital-entanglement is not specialized in the topological surface states. Here, we show the spin–orbital texture in a surface state of Bi(111) by laser-based spin- and angle-resolved photoelectron spectroscopy (laser-SARPES) and describe three-dimensional spin-rotation effect in photoemission resulting from spin-dependent quantum interference. Our model reveals that, in the spin–orbit-coupled systems, the spins pointing to the mutually opposite directions are independently locked to the orbital symmetries. Furthermore, direct detection of coherent spin phenomena by laser-SARPES enables us to clarify the phase of the dipole transition matrix element responsible for the spin direction in photoexcited states. These results permit the tuning of the spin polarization of optically excited electrons in solids with strong spin–orbit interaction. PMID:28232721

  11. Spin-dependent quantum interference in photoemission process from spin-orbit coupled states

    NASA Astrophysics Data System (ADS)

    Yaji, Koichiro; Kuroda, Kenta; Toyohisa, Sogen; Harasawa, Ayumi; Ishida, Yukiaki; Watanabe, Shuntaro; Chen, Chuangtian; Kobayashi, Katsuyoshi; Komori, Fumio; Shin, Shik

    2017-02-01

    Spin-orbit interaction entangles the orbitals with the different spins. The spin-orbital-entangled states were discovered in surface states of topological insulators. However, the spin-orbital-entanglement is not specialized in the topological surface states. Here, we show the spin-orbital texture in a surface state of Bi(111) by laser-based spin- and angle-resolved photoelectron spectroscopy (laser-SARPES) and describe three-dimensional spin-rotation effect in photoemission resulting from spin-dependent quantum interference. Our model reveals that, in the spin-orbit-coupled systems, the spins pointing to the mutually opposite directions are independently locked to the orbital symmetries. Furthermore, direct detection of coherent spin phenomena by laser-SARPES enables us to clarify the phase of the dipole transition matrix element responsible for the spin direction in photoexcited states. These results permit the tuning of the spin polarization of optically excited electrons in solids with strong spin-orbit interaction.

  12. Spin-dependent heat transport and thermal boundary resistance

    NASA Astrophysics Data System (ADS)

    Jeong, Taehee

    In this thesis, thermal conductivity change depending on the magnetic configurations has been studied. In order to make different magnetic configurations, we developed a spin valve structure, which has high MR ratio and low saturation field. The high MR ratio was achieved using Co/Cu multilayer and 21A or 34A thick Cu layer. The low saturation field was obtained by implementing different coercivities of the successive ferromagnetic layers. For this purpose, Co/Cu/Cu tri-layered structure was used with the thicknesses of the Co layers; 15 A and 30 A. For the thermal conductivity measurement, a three-omega method was employed with a thermally isolated microscale rod. We fabricated the microscale rod using optical lithography and MEMS process. Then the rod was wire-bonded to a chip-carver for further electrical measurement. For the thermal conductivity measurement, we built the three-omega measurement system using two lock-in amplifiers and two differential amplifiers. A custom-made electromagnet was added to the system to investigate the impact of magnetic field. We observed titanic thermal conductivity change depending on the magnetic configurations of the Co/Cu/Co multilayer. The thermal conductivity change was closely correlated with that of the electric conductivity in terms of the spin orientation, but the thermal conductivity was much more sensitive than that of the electric conductivity. The relative thermal conductivity change was 50% meanwhile that of electric resistivity change was 8.0%. The difference between the two ratios suggests that the scattering mechanism for charge and heat transport in the Co/Cu/Co multilayer is different. The Lorentz number in Weidemann-Franz law is also spin-dependent. Thermal boundary resistance between metal and dielectrics was also studied in this thesis. The thermal boundary resistance becomes critical for heat transport in a nanoscale because the thermal boundary resistance can potentially determine overall heat transport

  13. Spin-dependent limits from the DRIFT-IId directional dark matter detector

    NASA Astrophysics Data System (ADS)

    Daw, E.; Fox, J. R.; Gauvreau, J.-L.; Ghag, C.; Harmon, L. J.; Gold, M.; Lee, E. R.; Loomba, D.; Miller, E. H.; Murphy, A. Stj.; Paling, S. M.; Landers, J. M.; Pipe, M.; Pushkin, K.; Robinson, M.; Snowden-Ifft, D. P.; Spooner, N. J. C.; Walker, D.

    2012-02-01

    Data are presented from the DRIFT-IId detector operated in the Boulby Underground Science Facility in England. A 0.8 m3 fiducial volume, containing partial pressures of 30 Torr CS2 and 10 Torr CF4, was exposed for a duration of 47.4 live-time days with sufficient passive shielding to provide a neutron free environment within the detector. The nuclear recoil events seen are consistent with a remaining low-level background from the decay of radon daughters attached to the central cathode of the detector. However, charge from such events must drift across the entire width of the detector, and thus display large diffusion upon reaching the readout planes of the device. Exploiting this feature, it is shown to be possible to reject energy depositions from these Radon Progeny Recoil events while still retaining sensitivity to fiducial-volume nuclear recoil events. The response of the detector is then interpreted, using the F nuclei content of the gas, in terms of sensitivity to proton spin-dependent WIMP-nucleon interactions, displaying a minimum in sensitivity cross section at 1.8 pb for a WIMP mass of 100 GeV/c2. This sensitivity was achieved without compromising the direction sensitivity of DRIFT.

  14. Asteroseismic constraints on asymmetric dark matter: Light particles with an effective spin-dependent coupling

    NASA Astrophysics Data System (ADS)

    Martins, André; Lopes, Ilídio; Casanellas, Jordi

    2017-01-01

    So far, direct detection searches have come up empty handed in their quest for dark matter (DM). Meanwhile, asteroseismology arises as a complementary tool to study DM, as its accumulation in a star can enhance energy transport by providing a conduction mechanism, producing significant changes in the stellar structure during the course of the star's evolution. The stellar core, particularly affected by the presence of DM, can be investigated through precise asteroseismic diagnostics. We modeled three stars including DM energy transport: the Sun; a slightly less massive and much older star, KIC 7871531 (0.85 M⊙ , 9.41 Gyr); and a more massive and younger one, KIC 8379927 (1.12 M⊙ , 1.82 Gyr). We considered both the case of weakly interactive massive particles, albeit with a low annihilation, and the case of asymmetric DM for which the number of trapped particles in the star can be much greater. By analyzing these models with asteroseismic separation ratios weighted towards the core, we found indications limiting the effective spin-dependent DM-proton coupling for masses of a few GeV. This independent result is very close to the most recent and most stringent direct detection DM constraints.

  15. Symmetry Analysis of Spin-Dependent Electric Dipole and Its Application to Magnetoelectric Effects

    NASA Astrophysics Data System (ADS)

    Matsumoto, Masashige; Chimata, Kosuke; Koga, Mikito

    2017-03-01

    Spin-dependent electric dipole operators are investigated group-theoretically for the emergence of an electric dipole induced by a single spin or by two spins, where the spin dependences are completely classified up to the quadratic order. For a single spin, a product of spin operators behaves as an even-parity electric quadrupole operator, which differs from an odd-parity electric dipole. The lack of the inversion symmetry allows the even- and odd-parity mixing, which leads to the electric dipole described by the electric quadruple operators. Point-group tables are given for classification of the possible spin-dependent electric dipoles and for the qualitative analysis of multiferroic properties, such as an emergent electric dipole moment coexisting with a magnetic moment, electromagnon excitation, and directional dichroism. The results can be applied to a magnetic ion in crystals or embedded in molecules at a site without the inversion symmetry. In the presence of an inversion symmetry, the electric dipole does not appear for a single spin. This is not the case for the electric dipole induced by two spins with antisymmetric spin dependence, which is known as vector spin chirality, in the presence of the inversion center between the two spins. In the absence of the inversion center, symmetric spin-dependent electric dipoles are also relevant. The detailed analysis of various symmetries of two-spin states is applied to spin dimer systems and the related multiferroic properties.

  16. Spin-dependent quantum transport in nanoscaled geometries

    NASA Astrophysics Data System (ADS)

    Heremans, Jean J.

    2011-10-01

    We discuss experiments where the spin degree of freedom leads to quantum interference phenomena in the solid-state. Under spin-orbit interactions (SOI), spin rotation modifies weak-localization to weak anti-localization (WAL). WAL's sensitivity to spin- and phase coherence leads to its use in determining the spin coherence lengths Ls in materials, of importance moreover in spintronics. Using WAL we measure the dependence of Ls on the wire width w in narrow nanolithographic ballistic InSb wires, ballistic InAs wires, and diffusive Bi wires with surface states with Rashba-like SOI. In all three systems we find that Ls increases with decreasing w. While theory predicts the increase for diffusive wires with linear (Rashba) SOI, we experimentally conclude that the increase in Ls under dimensional confinement may be more universal, with consequences for various applications. Further, in mesoscopic ring geometries on an InAs/AlGaSb 2D electron system (2DES) we observe both Aharonov-Bohm oscillations due to spatial quantum interference, and Altshuler-Aronov-Spivak oscillations due to time-reversed paths. A transport formalism describing quantum coherent networks including ballistic transport and SOI allows a comparison of spin- and phase coherence lengths extracted for such spatial- and temporal-loop quantum interference phenomena. We further applied WAL to study the magnetic interactions between a 2DES at the surface of InAs and local magnetic moments on the surface from rare earth (RE) ions (Gd3+, Ho3+, and Sm3+). The magnetic spin-flip rate carries information about magnetic interactions. Results indicate that the heavy RE ions increase the SOI scattering rate and the spin-flip rate, the latter indicating magnetic interactions. Moreover Ho3+ on InAs yields a spin-flip rate with an unusual power 1/2 temperature dependence, possibly characteristic of a Kondo system. We acknowledge funding from DOE (DE-FG02-08ER46532).

  17. Disordered Quantum Gases and Spin-Dependent Lattices

    DTIC Science & Technology

    2013-07-07

    Hubbard Model, DAMOP (2011)/Poster Joshua Zirbel, Stanimir Kondov, William McGehee, Brian DeMarco, Anderson Localization of Ultracold Fermionic K, DAMOP...an Optical Lattice, DAMOP (2010)/Poster Joshua Zirbel, Stanimir Kondov, William McGehee, Brian DeMarco, Fermions in a 3-D Disordered Potential, DAMOP...precisely at the onset of localization. For these measurements, we used a spin-polarized, non-interacting gas of fermionic 40K atoms. The gas was

  18. Spin-Dependent Scattering off Neutral Donors in Silicon Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Lo, C. C.; Bokor, J.; Schenkel, T.; He, J.; Tyryshkin, A. M.; Lyon, S. A.

    2008-03-01

    One promising route towards single donor spin readout for donor qubits in silicon is by detecting spin-dependent scattering of conduction electrons by the neutral donors. We use accumulation-mode field-effect transistors formed in isotopically enriched silicon to study this effect. Only small ensembles of donor spins are present in our devices, ruling out bolometric effects caused by bulk donors. Spin-dependent scattering was detected using electrically detected magnetic resonance (EDMR) where spectra show resonant changes in the source-drain voltage for conduction electrons and electrons bound to donors. The utilization of spin-dependent scattering for the readout of donor spin-states in silicon based quantum computers will be discussed.

  19. Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure.

    PubMed

    Akerib, D S; Alsum, S; Araújo, H M; Bai, X; Bailey, A J; Balajthy, J; Beltrame, P; Bernard, E P; Bernstein, A; Biesiadzinski, T P; Boulton, E M; Brás, P; Byram, D; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chiller, A A; Chiller, C; Currie, A; Cutter, J E; Davison, T J R; Dobi, A; Dobson, J E Y; Druszkiewicz, E; Edwards, B N; Faham, C H; Fallon, S R; Fiorucci, S; Gaitskell, R J; Gehman, V M; Ghag, C; Gilchriese, M G D; Hall, C R; Hanhardt, M; Haselschwardt, S J; Hertel, S A; Hogan, D P; Horn, M; Huang, D Q; Ignarra, C M; Jacobsen, R G; Ji, W; Kamdin, K; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, N A; Lee, C; Lenardo, B G; Lesko, K T; Lindote, A; Lopes, M I; Manalaysay, A; Mannino, R L; Marzioni, M F; McKinsey, D N; Mei, D-M; Mock, J; Moongweluwan, M; Morad, J A; Murphy, A St J; Nehrkorn, C; Nelson, H N; Neves, F; O'Sullivan, K; Oliver-Mallory, K C; Palladino, K J; Pease, E K; Reichhart, L; Rhyne, C; Shaw, S; Shutt, T A; Silva, C; Solmaz, M; Solovov, V N; Sorensen, P; Stephenson, S; Sumner, T J; Szydagis, M; Taylor, D J; Taylor, W C; Tennyson, B P; Terman, P A; Tiedt, D R; To, W H; Tripathi, M; Tvrznikova, L; Uvarov, S; Velan, V; Verbus, J R; Webb, R C; White, J T; Whitis, T J; Witherell, M S; Wolfs, F L H; Xu, J; Yazdani, K; Young, S K; Zhang, C

    2017-06-23

    We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5  kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41}  cm^{2} (σ_{p}=5×10^{-40}  cm^{2}) at 35  GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

  20. Limits on spin-dependent WIMP-nucleon cross section obtained from the complete LUX exposure

    DOE PAGES

    Akerib, D. S.; Alsum, S.; Araújo, H. M.; ...

    2017-06-23

    We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn = 1.6 × 10–41 cm2 (σp = 5 × 10–40 cm2) at 35 GeV c–2, almost a sixfold improvement over the previous LUX spin-dependent results. Finally, the spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

  1. Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure

    NASA Astrophysics Data System (ADS)

    Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fallon, S. R.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Velan, V.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.; LUX Collaboration

    2017-06-01

    We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn=1.6 ×10-41 cm2 (σp=5 ×10-40 cm2 ) at 35 GeV c-2 , almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

  2. Spin-dependent Seebeck effects in a graphene nanoribbon coupled to two square lattice ferromagnetic leads

    SciTech Connect

    Zhou, Benhu Zeng, Yangsu; Zhou, Benliang; Zhou, Guanghui; Ouyang, Tao

    2015-03-14

    We theoretically investigate spin-dependent Seebeck effects for a system consisting of a narrow graphene nanoribbon (GNR) contacted to square lattice ferromagnetic (FM) electrodes with noncollinear magnetic moments. Both zigzag-edge graphene nanoribbons (ZGNRs) and armchair-edge graphene nanoribbons (AGNRs) were considered. Compared with our previous work with two-dimensional honeycomb-lattice FM leads, a more realistic model of two-dimensional square-lattice FM electrodes is adopted here. Using the nonequilibrium Green's function method combining with the tight-binding Hamiltonian, it is demonstrated that both the charge Seebeck coefficient S{sub C} and the spin-dependent Seebeck coefficient S{sub S} strongly depend on the geometrical contact between the GNR and the leads. In our previous work, S{sub C} for a semiconducting 15-AGNR system near the Dirac point is two orders of magnitude larger than that of a metallic 17-AGNR system. However, S{sub C} is the same order of magnitude for both metallic 17-AGNR and semiconducting 15-AGNR systems in the present paper because of the lack of a transmission energy gap for the 15-AGNR system. Furthermore, the spin-dependent Seebeck coefficient S{sub S} for the systems with 20-ZGNR, 17-AGNR, and 15-AGNR is of the same order of magnitude and its maximum absolute value can reach 8 μV/K. The spin-dependent Seebeck effects are not very pronounced because the transmission coefficient weakly depends on spin orientation. Moreover, the spin-dependent Seebeck coefficient is further suppressed with increasing angle between the relative alignments of magnetization directions of the two leads. Additionally, the spin-dependent Seebeck coefficient can be strongly suppressed for larger disorder strength. The results obtained here may provide valuable theoretical guidance in the experimental design of heat spintronic devices.

  3. Spin-dependent Seebeck effects in a graphene nanoribbon coupled to two square lattice ferromagnetic leads

    NASA Astrophysics Data System (ADS)

    Zhou, Benhu; Zhou, Benliang; Zeng, Yangsu; Zhou, Guanghui; Ouyang, Tao

    2015-03-01

    We theoretically investigate spin-dependent Seebeck effects for a system consisting of a narrow graphene nanoribbon (GNR) contacted to square lattice ferromagnetic (FM) electrodes with noncollinear magnetic moments. Both zigzag-edge graphene nanoribbons (ZGNRs) and armchair-edge graphene nanoribbons (AGNRs) were considered. Compared with our previous work with two-dimensional honeycomb-lattice FM leads, a more realistic model of two-dimensional square-lattice FM electrodes is adopted here. Using the nonequilibrium Green's function method combining with the tight-binding Hamiltonian, it is demonstrated that both the charge Seebeck coefficient SC and the spin-dependent Seebeck coefficient SS strongly depend on the geometrical contact between the GNR and the leads. In our previous work, SC for a semiconducting 15-AGNR system near the Dirac point is two orders of magnitude larger than that of a metallic 17-AGNR system. However, SC is the same order of magnitude for both metallic 17-AGNR and semiconducting 15-AGNR systems in the present paper because of the lack of a transmission energy gap for the 15-AGNR system. Furthermore, the spin-dependent Seebeck coefficient SS for the systems with 20-ZGNR, 17-AGNR, and 15-AGNR is of the same order of magnitude and its maximum absolute value can reach 8 μV/K. The spin-dependent Seebeck effects are not very pronounced because the transmission coefficient weakly depends on spin orientation. Moreover, the spin-dependent Seebeck coefficient is further suppressed with increasing angle between the relative alignments of magnetization directions of the two leads. Additionally, the spin-dependent Seebeck coefficient can be strongly suppressed for larger disorder strength. The results obtained here may provide valuable theoretical guidance in the experimental design of heat spintronic devices.

  4. Spin-dependent scattering in multilayered magnetic rings.

    PubMed

    Castaño, F J; Morecroft, D; Jung, W; Ross, C A

    2005-09-23

    Narrow mesoscopic NiFe/Cu/Co elliptical rings exhibit room-temperature giant magnetoresistance with distinct resistance levels corresponding to three different micromagnetic states. The highest and lowest resistance states of the multilayer rings correspond to the Co layer being in a bidomain state, antiparallel or parallel, respectively, to the NiFe, while the intermediate resistance corresponds to the Co layer being in a vortex state. Micromagnetic simulations suggest that the behavior of these rings is dominated by magnetostatic interactions between the domain walls in the Co and NiFe layers. Additional magnetization states in the NiFe at low applied fields can account for the minor loop behavior.

  5. Spin dependent charge pumping in SiC metal-oxide-semiconductor field-effect-transistors

    NASA Astrophysics Data System (ADS)

    Bittel, B. C.; Lenahan, P. M.; Ryan, J. T.; Fronheiser, J.; Lelis, A. J.

    2011-08-01

    We demonstrate a very powerful electrically detected magnetic resonance (EDMR) technique, spin dependent charge pumping (SDCP) and apply it to 4H SiC metal-oxide-semiconductor field-effect-transistors. SDCP combines a widely used electrical characterization tool with the most powerful analytical technique for providing atomic scale structure of point defects in electronic materials. SDCP offers a large improvement in sensitivity over the previously established EDMR technique called spin dependent recombination, offering higher sensitivity and accessing a wider energy range within the bandgap.

  6. Spin-dependent electron transmission through bacteriorhodopsin embedded in purple membrane

    PubMed Central

    Mishra, Debabrata; Markus, Tal Z.; Naaman, Ron; Kettner, Matthias; Göhler, Benjamin; Zacharias, Helmut; Friedman, Noga; Sheves, Mordechai; Fontanesi, Claudio

    2013-01-01

    Spin-dependent photoelectron transmission and spin-dependent electrochemical studies were conducted on purple membrane containing bacteriorhodopsin (bR) deposited on gold, aluminum/aluminum-oxide, and nickel substrates. The result indicates spin selectivity in electron transmission through the membrane. Although the chiral bR occupies only about 10% of the volume of the membrane, the spin polarization found is on the order of 15%. The electrochemical studies indicate a strong dependence of the conduction on the protein’s structure. Denaturation of the protein causes a sharp drop in the conduction through the membrane. PMID:23980184

  7. Spin-dependent electron transmission through bacteriorhodopsin embedded in purple membrane.

    PubMed

    Mishra, Debabrata; Markus, Tal Z; Naaman, Ron; Kettner, Matthias; Göhler, Benjamin; Zacharias, Helmut; Friedman, Noga; Sheves, Mordechai; Fontanesi, Claudio

    2013-09-10

    Spin-dependent photoelectron transmission and spin-dependent electrochemical studies were conducted on purple membrane containing bacteriorhodopsin (bR) deposited on gold, aluminum/aluminum-oxide, and nickel substrates. The result indicates spin selectivity in electron transmission through the membrane. Although the chiral bR occupies only about 10% of the volume of the membrane, the spin polarization found is on the order of 15%. The electrochemical studies indicate a strong dependence of the conduction on the protein's structure. Denaturation of the protein causes a sharp drop in the conduction through the membrane.

  8. Spin-dependent polaron formation in pristine graphene

    NASA Astrophysics Data System (ADS)

    Mogulkoc, A.; Modarresi, M.; Kandemir, B. S.

    2015-02-01

    We investigate the effects of spin-orbit couplings on the electron (hole)-E2g phonon interaction in graphene. We examine the effects of spin-orbit couplings on electron and hole polaron formation as well as DC conductivity, and spin polarizations of charge carriers. We use Fröhlich type Hamiltonian to describe the electron-phonon system within the continuum limit. Our theoretical analysis shows that, the polaronic effect is decreased due to the spin-orbit couplings, for both spin and pseudospin states, but it is enhanced beyond some critical values of wavevector for spin-up states of both sublattices in the presence of spin-orbit couplings. The Rashba spin-orbit coupling in the graphene single layer splits up- and down- states, and produces perfect spin polarized conductivity. Also the phonon-restricted and phonon-assisted conduction are reported for positive and negative Fermi energies.

  9. Spin-dependent mechanism for diatomic ligand binding to heme

    NASA Astrophysics Data System (ADS)

    Franzen, Stefan

    2002-12-01

    The nature of diatomic ligand recombination in heme proteins is elucidated by using a Landau-Zener model for the electronic coupling in the recombination rate constant. The model is developed by means of explicit potential energy surfaces calculated by using density functional theory (DFT). The interaction of all possible spin states of the three common diatomic ligands, CO, NO, and O2, and high-spin heme iron is compared. The electronic coupling, rebinding barrier, and Landau-Zener force terms can be obtained and used to demonstrate significant differences among the ligands. In particular the intermediate spin states of NO (S = 3/2) and O2 (S = 1) are shown to be bound states. Rapid recombination occurs from these bound states in agreement with experimental data. The slower phases of O2 recombination can be explained by the presence of two higher spin states, S = 2 and S = 3, which have a small and relatively large barrier to ligand recombination, respectively. By contrast, the intermediate spin state for CO is not a bound state, and the only recombination pathway for CO involves direct recombination from the S = 2 state. This process is significantly slower according to the Landau-Zener model. Quantitative estimates of the parameters used in the rate constants provide a complete description that explains rebinding rates that range from femtoseconds to milliseconds at ambient temperature.

  10. Spin-dependent delay time in ferromagnet/insulator/ferromagnet heterostructures

    SciTech Connect

    Xie, ZhengWei; Zheng Shi, De; Lv, HouXiang

    2014-07-07

    We study theoretically spin-dependent group delay and dwell time in ferromagnet/insulator/ferromagnet (FM/I/FM) heterostructure. The results indicate that, when the electrons with different spin orientations tunnel through the FM/I/FM junction, the spin-up process and the spin-down process are separated on the time scales. As the self-interference delay has the spin-dependent features, the variations of spin-dependent dwell-time and spin-dependent group-delay time with the structure parameters appear different features, especially, in low incident energy range. These different features show up as that the group delay times for the spin-up electrons are always longer than those for spin-down electrons when the barrier height or incident energy increase. In contrast, the dwell times for the spin-up electrons are longer (shorter) than those for spin-down electrons when the barrier heights (the incident energy) are under a certain value. When the barrier heights (the incident energy) exceed a certain value, the dwell times for the spin-up electrons turn out to be shorter (longer) than those for spin-down electrons. In addition, the group delay time and the dwell time for spin-up and down electrons also relies on the comparative direction of magnetization in two FM layers and tends to saturation with the thickness of the barrier.

  11. Tunable spin-dependent splitting of light beam in a chiral metamaterial slab

    NASA Astrophysics Data System (ADS)

    Huang, Y. Y.; Yu, Z. W.; Gao, Lei

    2014-07-01

    Spin-dependent splitting of the reflected beam for the chiral metamaterial slab is investigated by analyzing the spatial transverse shifts (TSs) of the two spin-dependent components of the reflected beam. Two components refer to the right-circularly polarized and left-circularly polarized reflected wave components. The influences of the physical parameters and the polarization of the incident beam on the spin-dependent splitting are discussed. The results show that two components are asymmetric due to the cross-polarization of the electromagnetic fields in chiral slab. By adjusting the angle of incidence and the polarization state of the incident beam, the spatial splitting can be enhanced. Moreover, the effect of the thickness on the spatial TSs of the two components becomes weak with increasing the angle of incidence. To one's interest, the spin-dependent splitting also can be realized for two special linear (TE and TM) polarization. Our study may provide an opportunity to realize and control the transverse splitting of the light, and open up the possibility for developing new nanophotonic devices.

  12. Spin-dependent Peltier effect of perpendicular currents in multilayered nanowires

    NASA Astrophysics Data System (ADS)

    Gravier, Laurent; Serrano-Guisan, Santiago; Reuse, François; Ansermet, J.-Ph.

    2006-02-01

    Heat and charge transport perpendicular to Co/Cu multilayers are characterized by magnetoresistance and magnetothermoelectrical power. Furthermore, a very large voltage response to temperature oscillations under a dc current is observed, which depends strongly on the applied magnetic field. This effect is ascribed to a Peltier effect and its field dependence to a spin dependence of the Peltier coefficient.

  13. Ferromagnetic nanoscale electron correlation promoted by organic spin-dependent delocalization.

    PubMed

    Kirk, Martin L; Shultz, David A; Schmidt, Robert D; Habel-Rodriguez, Diana; Lee, Hyoyoung; Lee, Junghyun

    2009-12-30

    We describe the electronic structure and the origin of ferromagnetic exchange coupling in two new metal complexes, NN-SQ-Co(III)(py)(2)Cat-NN (1) and NN-Ph-SQ-Co(III)(py)(2)Cat-Ph-NN (2) (NN = nitronylnitroxide radical, Ph = 1,4-phenylene, SQ = S = (1)/(2) semiquinone radical, Cat = S = 0 catecholate, and py = pyridine). Near-IR electronic absorption spectroscopy for 1 and 2 reveals a low-energy optical band that has been assigned as a Psi(u) --> Psi(g) transition involving bonding and antibonding linear combinations of delocalized dioxolene (SQ/Cat) valence frontier molecular orbitals. The ferromagnetic exchange interaction in 1 is so strong that only the high-spin quartet state (S(T) = (3)/(2)) is thermally populated at temperatures up to 300 K. The temperature-dependent magnetic susceptibility data for 2 reveals that an excited state spin doublet (S(T) = (1)/(2)) is populated at higher temperatures, indicating that the phenylene spacer modulates the magnitude of the magnetic exchange. The valence delocalization within the dioxolene dyad of 2 results in ferromagnetic alignment of two localized NN radicals separated by over 22 A. The ferromagnetic exchange in 1 and 2 results from a spin-dependent delocalization (double exchange type) process and the origin of this strong electron correlation has been understood in terms of a valence bond configuration interaction (VBCI) model. We show that ferromagnetic coupling promoted by organic mixed-valency provides keen insight into the ability of single molecules to communicate spin information over nanoscale distances. Furthermore, the strong interaction between the itinerant dioxolene electron and localized NN electron spins impacts our ability to understand the exchange interaction between delocalized electrons and pinned magnetic impurities in technologically important dilute magnetic semiconductor materials. The long correlation length (22 A) of the itinerant electron that mediates this coupling indicates that high

  14. Ferromagnetic Nanoscale Electron Correlation Promoted by Organic Spin-Dependent Delocalization

    PubMed Central

    Schmidt, Robert D.; Habel-Rodriguez, Diana; Lee, Junghyun

    2012-01-01

    We describe the electronic structure and the origin of ferromagnetic exchange coupling in two new metal complexes, NN-SQ-CoIII(py)2Cat-NN (1) and NN-Ph-SQ-CoIII(py)2Cat-Ph-NN (2) (NN = nitronylnitroxide radical, Ph = 1,4-phenylene, SQ = S = 1/2 semiquinone radical, Cat = S = 0 catecholate, and py = pyridine). Near-IR electronic absorption spectroscopy for 1 and 2 reveals a low energy optical band that has been assigned as a Ψu → Ψg transition involving bonding and antibonding linear combinations of delocalized dioxolene (SQ/Cat) valence frontier molecular orbitals. The ferromagnetic exchange interaction in 1 is so strong that only the high-spin quartet state (ST = 3/2) is thermally populated at temperatures up to 300 K. The temperature-dependent magnetic susceptibility data for 2 reveals that an excited state spin doublet (ST = 1/2) is populated at higher temperatures, indicating that the phenylene spacer modulates the magnitude of the magnetic exchange. The valence delocalization within the dioxolene dyad of 2 results in ferromagnetic alignment of two localized NN radicals separated by over 22 Å. The ferromagnetic exchange in 1 and 2 results from a spin-dependent delocalization (double exchange type) process and the origin of this strong electron correlation has been understood in terms of a valence bond configuration interaction (VBCI) model. We show that ferromagnetic coupling promoted by organic mixed-valency provides keen insight into the ability of single molecules to communicate spin information over nanoscale distances. Furthermore, the strong interaction between the itinerant dioxolene electron and localized NN electron spins impacts our ability to understand the exchange interaction between delocalized electrons and pinned magnetic impurities in technologically important dilute magnetic semiconductor materials. The long correlation length (22 Å) of the itinerant electron that mediates this coupling indicates that high-spin π-delocalized organic

  15. Tunable Spin dependent beam shift by simultaneously tailoring geometric and dynamical phases of light in inhomogeneous anisotropic medium

    NASA Astrophysics Data System (ADS)

    Pal, Mandira; Banerjee, Chitram; Chandel, Shubham; Bag, Ankan; Majumder, Shovan K.; Ghosh, Nirmalya

    2016-12-01

    Spin orbit interaction and the resulting Spin Hall effect of light are under recent intensive investigations because of their fundamental nature and potential applications. Here, we report an interesting manifestation of spin Hall effect of light and demonstrate its tunability in an inhomogeneous anisotropic medium exhibiting spatially varying retardance level. In our system, the beam shift occurs only for one circular polarization mode keeping the other orthogonal mode unaffected, which is shown to arise due to the combined spatial gradients of the geometric phase and the dynamical phase of light. The constituent two orthogonal circular polarization modes of an input linearly polarized light evolve in different trajectories, eventually manifesting as a large and tunable spin separation. The spin dependent beam shift and the demonstrated principle of simultaneously tailoring space-varying geometric and dynamical phase of light for achieving its tunability (of both magnitude and direction), may provide an attractive route towards development of spin-optical devices.

  16. Tunable Spin dependent beam shift by simultaneously tailoring geometric and dynamical phases of light in inhomogeneous anisotropic medium.

    PubMed

    Pal, Mandira; Banerjee, Chitram; Chandel, Shubham; Bag, Ankan; Majumder, Shovan K; Ghosh, Nirmalya

    2016-12-22

    Spin orbit interaction and the resulting Spin Hall effect of light are under recent intensive investigations because of their fundamental nature and potential applications. Here, we report an interesting manifestation of spin Hall effect of light and demonstrate its tunability in an inhomogeneous anisotropic medium exhibiting spatially varying retardance level. In our system, the beam shift occurs only for one circular polarization mode keeping the other orthogonal mode unaffected, which is shown to arise due to the combined spatial gradients of the geometric phase and the dynamical phase of light. The constituent two orthogonal circular polarization modes of an input linearly polarized light evolve in different trajectories, eventually manifesting as a large and tunable spin separation. The spin dependent beam shift and the demonstrated principle of simultaneously tailoring space-varying geometric and dynamical phase of light for achieving its tunability (of both magnitude and direction), may provide an attractive route towards development of spin-optical devices.

  17. Light-front spin-dependent spectral function and nucleon momentum distributions for a three-body system

    NASA Astrophysics Data System (ADS)

    Del Dotto, Alessio; Pace, Emanuele; Salmè, Giovanni; Scopetta, Sergio

    2017-01-01

    Poincaré covariant definitions for the spin-dependent spectral function and for the momentum distributions within the light-front Hamiltonian dynamics are proposed for a three-fermion bound system, starting from the light-front wave function of the system. The adopted approach is based on the Bakamjian-Thomas construction of the Poincaré generators, which allows one to easily import the familiar and wide knowledge on the nuclear interaction into a light-front framework. The proposed formalism can find useful applications in refined nuclear calculations, such as those needed for evaluating the European Muon Collaboration effect or the semi-inclusive deep inelastic cross sections with polarized nuclear targets, since remarkably the light-front unpolarized momentum distribution by definition fulfills both normalization and momentum sum rules. Also shown is a straightforward generalization of the definition of the light-front spectral function to an A -nucleon system.

  18. Tunable Spin dependent beam shift by simultaneously tailoring geometric and dynamical phases of light in inhomogeneous anisotropic medium

    PubMed Central

    Pal, Mandira; Banerjee, Chitram; Chandel, Shubham; Bag, Ankan; Majumder, Shovan K.; Ghosh, Nirmalya

    2016-01-01

    Spin orbit interaction and the resulting Spin Hall effect of light are under recent intensive investigations because of their fundamental nature and potential applications. Here, we report an interesting manifestation of spin Hall effect of light and demonstrate its tunability in an inhomogeneous anisotropic medium exhibiting spatially varying retardance level. In our system, the beam shift occurs only for one circular polarization mode keeping the other orthogonal mode unaffected, which is shown to arise due to the combined spatial gradients of the geometric phase and the dynamical phase of light. The constituent two orthogonal circular polarization modes of an input linearly polarized light evolve in different trajectories, eventually manifesting as a large and tunable spin separation. The spin dependent beam shift and the demonstrated principle of simultaneously tailoring space-varying geometric and dynamical phase of light for achieving its tunability (of both magnitude and direction), may provide an attractive route towards development of spin-optical devices. PMID:28004825

  19. Distorted spin dependent spectral function of {sup 3}He and semi-inclusive deep inelastic scattering processes

    SciTech Connect

    Kaptari, Leonya P.; Del Dotto, Alessio; Pace, Emanuele; Salme, Giovanni; Scopetta, Sergio

    2014-03-01

    The spin dependent spectral function, relevant to describe polarized electron scattering off polarized {sup 3}He, is studied, within the Plane Wave Impulse Approximation and taking into account final state interaction effects (FSI). In particular, the case of semi-inclusive deep inelastic scattering (SiDIS) is considered, evaluating the FSI of the hadronizing quark with the nuclear remnants. It is shown that particular kinematical regions can be selected to minimize the latter effects, so that parton distributions in the neutron can be accessed. On the other side, in the regions where FSI dominates, the considered reactions can elucidate the mechanism of hadronization of quarks during the propagation in the nuclear medium. It is shown that the obtained spin dependent spectral function can be directly applied to investigate the SiDIS reaction e-vector + {sup 3}He-vector to h+X, where the hadron h originates from the current fragmentation. Experiments of this type are being performed at JLab to extract neutron transverse momentum dependent parton distributions. As a case study, a different SiDIS process, with detection of slow (A-1) systems in the final state, is considered in more details, in order to establish when nuclear structure effects and FSI can be distinguished from elementary reactions on quasi-free nucleons. It is argued that, by a proper choice of kinematics, the origin of nuclear effects in polarized DIS phenomena and the details of the interaction between the hadronizing quark and the nuclear medium can be investigated at a level which is not reachable in inclusive deep inelastic scattering.

  20. Optically pumped NMR: Revealing spin-dependent Landau level transitions in GaAs

    NASA Astrophysics Data System (ADS)

    Ramaswamy, K.; Mui, S.; Crooker, S. A.; Pan, X.; Sanders, G. D.; Stanton, C. J.; Hayes, S. E.

    2010-08-01

    We show that high-resolution optically pumped NMR (OPNMR) studies can reveal spin-dependent optical transitions between valence- and conduction-band Landau levels in bulk semiconductors such as GaAs. The OPNMR signal intensity exhibits oscillations as a function of pump photon energy that evolve with magnetic field. In contrast to standard polarized magnetoabsorption measurements, OPNMR is sensitive to the polarization of the photoexcited electron spins (i.e., the difference between spin-up and spin-down electron populations rather than the sum). This allows one to clearly resolve the spin dependence of optical transitions that might normally be obscured in conventional magnetoabsorption studies. The data are in good agreement with theoretical calculations of the transitions from the spin-split light-hole Landau levels in the valence band to the conduction-band Landau levels of GaAs.

  1. Microwave control of atomic motional states in a spin-dependent optical lattice

    NASA Astrophysics Data System (ADS)

    Belmechri, Noomen; Förster, Leonid; Alt, Wolfgang; Widera, Artur; Meschede, Dieter; Alberti, Andrea

    2013-05-01

    Spin-dependent optical potentials allow us to use microwave radiation to manipulate the motional state of trapped neutral atoms (Förster et al 2009 Phys. Rev. Lett. 103 233001). Here, we discuss this method in greater detail, comparing it to the widely employed Raman sideband coupling method. We provide a simplified model for sideband cooling in a spin-dependent potential, and we discuss it in terms of the generalized Lamb-Dicke parameter. Using a master equation formalism, we present a quantitative analysis of the cooling performance for our experiment, which can be generalized to other experimental settings. We additionally use microwave sideband transitions to engineer motional Fock states and coherent states, and we devise a technique for measuring the population distribution of the prepared states.

  2. Spin-dependent electron transport in zinc- and manganese-doped adenine molecules

    SciTech Connect

    Simchi, Hamidreza; Esmaeilzadeh, Mahdi Mazidabadi, Hossein

    2014-01-28

    The spin-dependent electron transport properties of zinc- and manganese-doped adenine molecules connected to zigzag graphene leads are studied in the zero bias regime using the non-equilibrium Green's function method. The conductance of the adenine molecule increased and became spin-dependent when a zinc or manganese atom was doped into the molecules. The effects of a transverse electric field on the spin-polarization of the transmitted electrons were investigated and the spin-polarization was controlled by changing the transverse electric field. Under the presence of a transverse electric field, both the zinc- and manganese-doped adenine molecules acted as spin-filters. The maximum spin-polarization of the manganese-doped adenine molecule was greater than the molecule doped with zinc.

  3. Large current modulation and spin-dependent tunneling of vertical graphene/MoS2 heterostructures.

    PubMed

    Myoung, Nojoon; Seo, Kyungchul; Lee, Seung Joo; Ihm, G

    2013-08-27

    Vertical graphene heterostructures have been introduced as an alternative architecture for electronic devices by using quantum tunneling. Here, we present that the current on/off ratio of vertical graphene field-effect transistors is enhanced by using an armchair graphene nanoribbon as an electrode. Moreover, we report spin-dependent tunneling current of the graphene/MoS2 heterostructures. When an atomically thin MoS2 layer sandwiched between graphene electrodes becomes magnetic, Dirac fermions with different spins feel different heights of the tunnel barrier, leading to spin-dependent tunneling. Our finding will develop the present graphene heterostructures for electronic devices by improving the device performance and by adding the possibility of spintronics based on graphene.

  4. Spin-dependent Seebeck effects in graphene-based molecular junctions

    NASA Astrophysics Data System (ADS)

    Li, Jianwei; Wang, Bin; Xu, Fuming; Wei, Yadong; Wang, Jian

    2016-05-01

    We report a first-principles investigation of spin-dependent transport properties in two different graphene-based molecular junctions. By applying different temperatures between two leads without bias voltage, spin-dependent currents are driven which depend on reference temperature T , temperature gradient Δ T , and gate voltage Vg. Moreover, pure spin currents without charge currents can be obtained by adjusting T ,Δ T , and Vg for both molecular junctions. The directions of pure spin currents in these two molecular junctions are opposite, which can be understood by analyzing the transmission coefficients under equilibrium states. Spin thermopower, thermal conductance, and the figure of merit as functions of T ,Vg, and chemical potential μ were also investigated in the linear response regime. Large spin thermopower and spin figure of merit can be obtained by adjusting Vg and μ for each junction, which indicates proper application of spin caloritronic devices of our graphene-based molecular junctions.

  5. Spin-dependent gradient correction for more accurate atomization energies of molecules.

    PubMed

    Constantin, Lucian A; Fabiano, Eduardo; Della Sala, Fabio

    2012-11-21

    We discuss, simplify, and improve the spin-dependent correction of Constantin et al. [Phys. Rev. B 84, 233103 (2011)] for atomization energies, and develop a density parameter of the form v ∝ |∇n|/n(10/9), found from the statistical ensemble of one-electron densities. The here constructed exchange-correlation generalized gradient approximations (GGAs), named zvPBEsol and zvPBEint, show a broad applicability, and a good accuracy for many applications, because these corrected functionals significantly improve the atomization and binding energies of molecular systems, without worsening the behavior of the original functionals (PBEsol and PBEint) for other properties. This spin-dependent correction is also applied to meta-GGA dynamical correlation functionals combined with exact-exchange; in this case a significant (about 30%) improvement in atomization energies of small molecules is found.

  6. Impact of hadronic and nuclear corrections on global analysis of spin-dependent parton distributions

    SciTech Connect

    Jimenez-Delgado, Pedro; Accardi, Alberto; Melnitchouk, Wally

    2014-02-01

    We present the first results of a new global next-to-leading order analysis of spin-dependent parton distribution functions from the most recent world data on inclusive polarized deep-inelastic scattering, focusing in particular on the large-x and low-Q^2 regions. By directly fitting polarization asymmetries we eliminate biases introduced by using polarized structure function data extracted under nonuniform assumptions for the unpolarized structure functions. For analysis of the large-x data we implement nuclear smearing corrections for deuterium and 3He nuclei, and systematically include target mass and higher twist corrections to the g_1 and g_2 structure functions at low Q^2. We also explore the effects of Q^2 and W^2 cuts in the data sets, and the potential impact of future data on the behavior of the spin-dependent parton distributions at large x.

  7. Anisotropic spin-dependent electron tunneling in a triple-barrier resonant tunneling diode

    NASA Astrophysics Data System (ADS)

    Isić, Goran; Radovanović, Jelena; Milanović, Vitomir

    2007-12-01

    The one-band envelope function approximation is used to investigate the spin-dependent tunneling of conduction band electrons in semiconductor heterostructures when both the bulk inversion asymmetry (BIA) and structure inversion asymmetry (SIA) are present. It is shown that under certain conditions the interplay between BIA and SIA may be used to induce a strong dependence of transmission probabilities on the direction of electrons lateral momenta thus offering means to improve the existing designs of nonmagnetic semiconductor spin filters.

  8. Device Concepts Based on Spin-dependent Transmission in Semiconductor Heterostructures

    NASA Technical Reports Server (NTRS)

    Ting, David Z. - Y.; Cartoixa, X.

    2004-01-01

    We examine zero-magnetic-field spin-dependent transmission in nonmagnetic semiconductor heterostructures with structural inversion asymmetry (SIA) and bulk inversion asymmetry (BIA), and report spin devices concepts that exploit their properties. Our modeling results show that several design strategies could be used to achieve high spin filtering efficiencies. The current spin polarization of these devices is electrically controllable, and potentially amenable to highspeed spin modulation, and could be integrated in optoelectronic devices for added functionality.

  9. Device Concepts Based on Spin-dependent Transmission in Semiconductor Heterostructures

    NASA Technical Reports Server (NTRS)

    Ting, David Z. - Y.; Cartoixa, X.

    2004-01-01

    We examine zero-magnetic-field spin-dependent transmission in nonmagnetic semiconductor heterostructures with structural inversion asymmetry (SIA) and bulk inversion asymmetry (BIA), and report spin devices concepts that exploit their properties. Our modeling results show that several design strategies could be used to achieve high spin filtering efficiencies. The current spin polarization of these devices is electrically controllable, and potentially amenable to highspeed spin modulation, and could be integrated in optoelectronic devices for added functionality.

  10. A NEW METHOD FOR EXTRACTING SPIN-DEPENDENT NEUTRON STRUCTURE FUNCTIONS FROM NUCLEAR DATA

    SciTech Connect

    Kahn, Y.F.; Melnitchouk, W.

    2009-01-01

    High-energy electrons are currently the best probes of the internal structure of nucleons (protons and neutrons). By collecting data on electrons scattering off light nuclei, such as deuterium and helium, one can extract structure functions (SFs), which encode information about the quarks that make up the nucleon. Spin-dependent SFs, which depend on the relative polarization of the electron beam and the target nucleus, encode quark spins. Proton SFs can be measured directly from electron-proton scattering, but those of the neutron must be extracted from proton data and deuterium or helium-3 data because free neutron targets do not exist. At present, there is no reliable method for accurately determining spin-dependent neutron SFs in the low-momentum-transfer regime, where nucleon resonances are prominent and the functions are not smooth. The focus of this study was to develop a new method for extracting spin-dependent neutron SFs from nuclear data. An approximate convolution formula for nuclear SFs reduces the problem to an integral equation, for which a recursive solution method was designed. The method was then applied to recent data from proton and deuterium scattering experiments to perform a preliminary extraction of spin-dependent neutron SFs in the resonance region. The extraction method was found to reliably converge for arbitrary test functions, and the validity of the extraction from data was verifi ed using a Bjorken integral, which relates integrals of SFs to a known quantity. This new information on neutron structure could be used to assess quark-hadron duality for the neutron, which requires detailed knowledge of SFs in all kinematic regimes.

  11. Spin-dependent transport in elemental and compound semiconductors and nanostructures

    NASA Astrophysics Data System (ADS)

    Brandt, M. S.; Goennenwein, S. T. B.; Graf, T.; Huebl, H.; Lauterbach, S.; Stutzmann, M.

    2004-07-01

    The results obtained on spin-dependent processes via electrically detected magnetic resonance (EDMR), capacitance-detected magnetic resonance (CDMR) and noise-detected magnetic resonance (NDMR) in a variety of different semiconductor materials, devices and nanostructures are reviewed. Similar to optically detected magnetic resonance (ODMR), these detection methods are significantly more sensitive for the detection of paramagnetic states and defects than conventional electron spin resonance (ESR) and can be applied also to semiconductors with an indirect band gap. Using GaAs/AlGaAs-heterostructures and thin films of amorphous hydrogenated silicon (a-Si:H) as examples, the physics of spin-dependent recombination and its detection via spin-dependent photoconductivity is briefly recapitulated. EDMR on pn-diodes from GaP, GaAsP and group-III nitrides, resonant spin-spin scattering in strained Si/SiGe heterostructures, new hysteresis effects in the longitudinal magneto-transport through two-dimensional electron gases and edge-magneto plasmons in different III-V heterostructures are discussed. Various aspects of ferromagnetic III-V semiconductors are investigated, including doping of GaN with Mn, inhomogeneous magnetization of GaMnAs and control of ferromagnetism in semiconductors via hydrogen. Finally, preliminary EDMR experiments on the detection of single paramagnetic defects in MOSFETs via random telegraph noise are presented.

  12. Spin-dependent electrical conduction in a pentacene Schottky diode explored by electrically detected magnetic resonance

    NASA Astrophysics Data System (ADS)

    Fukuda, Kunito; Asakawa, Naoki

    2017-02-01

    Reported is the observation of dark spin-dependent electrical conduction in a Schottky barrier diode with pentacene (PSBD) using electrically detected magnetic resonance at room temperature. It is suggested that spin-dependent conduction exists in pentacene thin films, which is explored by examining the anisotropic linewidth of the EDMR signal and current density-voltage (J-V) measurements. The EDMR spectrum can be decomposed to Gaussian and Lorentzian components. The dependency of the two signals on the applied voltage was consistent with the current density-voltage (J-V) of the PSBD rather than that of the electron-only device of Al/pentacene/Al, indicating that the spin-dependent conduction is due to bipolaron formation associated with hole polaronic hopping processes. The applied-voltage dependence of the ratio of intensity of the Gaussian line to the Lorentzian may infer that increasing current density should make conducting paths more dispersive, thereby resulting in an increased fraction of the Gaussian line due to the higher dispersive g-factor.

  13. Spin-dependent recombination at arsenic donors in ion-implanted silicon

    SciTech Connect

    Franke, David P. Brandt, Martin S.; Otsuka, Manabu; Matsuoka, Takashi; Itoh, Kohei M.; Vlasenko, Leonid S.; Vlasenko, Marina P.

    2014-09-15

    Spin-dependent transport processes in thin near-surface doping regions created by low energy ion implantation of arsenic in silicon are detected by two methods, spin-dependent recombination using microwave photoconductivity and electrically detected magnetic resonance monitoring the direct current through the sample. The high sensitivity of these techniques allows the observation of the magnetic resonance, in particular, of As in weak magnetic fields and at low resonance frequencies (40–1200 MHz), where high-field-forbidden transitions between the magnetic sublevels can be observed due to the mixing of electron and nuclear spin states. Several implantation-induced defects are present in the samples studied and act as spin readout partner. We explicitly demonstrate this by electrically detected electron double resonance experiments and identify a pair recombination of close pairs formed by As donors and oxygen-vacancy centers in an excited triplet state (SL1) as the dominant spin-dependent process in As-implanted Czochralski-grown Si.

  14. Spin-dependent charge recombination along para-phenylene molecular wires

    NASA Astrophysics Data System (ADS)

    Fay, Thomas P.; Lewis, Alan M.; Manolopoulos, David E.

    2017-08-01

    We have used an efficient new quantum mechanical method for radical pair recombination reactions to study the spin-dependent charge recombination along PTZ•+-Phn-PDI•- molecular wires. By comparing our results with the experimental data of Weiss et al. [J. Am. Chem. Soc. 126, 5577 (2004)], we are able to extract the spin-dependent (singlet and triplet) charge recombination rate constants for wires with n = 2-5. These spin-dependent rate constants have not been extracted previously from the experimental data because they require fitting its magnetic field-dependence to the results of quantum spin dynamics simulations. We find that the triplet recombination rate constant decreases exponentially with the length of the wire, consistent with the superexchange mechanism of charge recombination. However, the singlet recombination rate constant is nearly independent of the length of the wire, suggesting that the singlet pathway is dominated by an incoherent hopping mechanism. A simple qualitative explanation for the different behaviours of the two spin-selective charge recombination pathways is provided in terms of Marcus theory. We also find evidence for a magnetic field-independent background contribution to the triplet yield of the charge recombination reaction and suggest several possible explanations for it. Since none of these explanations is especially compelling given the available experimental evidence, and since the result appears to apply more generally to other molecular wires, we hope that this aspect of our study will stimulate further experimental work.

  15. Spin-dependent recombination at arsenic donors in ion-implanted silicon

    NASA Astrophysics Data System (ADS)

    Franke, David P.; Otsuka, Manabu; Matsuoka, Takashi; Vlasenko, Leonid S.; Vlasenko, Marina P.; Brandt, Martin S.; Itoh, Kohei M.

    2014-09-01

    Spin-dependent transport processes in thin near-surface doping regions created by low energy ion implantation of arsenic in silicon are detected by two methods, spin-dependent recombination using microwave photoconductivity and electrically detected magnetic resonance monitoring the direct current through the sample. The high sensitivity of these techniques allows the observation of the magnetic resonance, in particular, of As in weak magnetic fields and at low resonance frequencies (40-1200 MHz), where high-field-forbidden transitions between the magnetic sublevels can be observed due to the mixing of electron and nuclear spin states. Several implantation-induced defects are present in the samples studied and act as spin readout partner. We explicitly demonstrate this by electrically detected electron double resonance experiments and identify a pair recombination of close pairs formed by As donors and oxygen-vacancy centers in an excited triplet state (SL1) as the dominant spin-dependent process in As-implanted Czochralski-grown Si.

  16. Spin-dependent x-ray absorption of MnO and MnF[sub 2

    SciTech Connect

    Haemaelaeinen, K.; Kao, C.; Hastings, J.B.; Siddons, D.P.; Berman, L.E.; Stojanoff, V.; Cramer, S.P. )

    1992-12-01

    A method to measure spin-dependent x-ray-absorption spectra that does not require long-range magnetic order is presented. It is based on the spin dependence of the emission spectrum. Using a high-resolution spectrometer to separate and select the different spin-polarized final states in the [ital K][beta] fluorescence spectrum of MnO and MnF[sub 2], spin-dependent absorption spectra in the vicinity of the Mn [ital K] edge were measured. Since this method uses the direction of the local magnetic moment as a reference it can be applied to paramagnetic and antiferromagnetic systems as well as to ferromagnetic.

  17. Spin-dependent Fabry-Pérot interference from a Cu thin film grown on fcc Co(001).

    PubMed

    Wu, Y Z; Schmid, A K; Altman, M S; Jin, X F; Qiu, Z Q

    2005-01-21

    Spin-dependent electron reflection from a Cu thin film grown on Co/Cu(001) was investigated using spin-polarized low-energy electron microscopy (SPLEEM). Fabry-Pe rot type interference was observed and is explained using the phase accumulation model. SPLEEM images of the Cu overlayer reveal magnetic domains in the Co underlayer, with the domain contrast oscillating with electron energy and Cu film thickness. This behavior is attributed to the spin-dependent electron reflectivity at the Cu/Co interface which leads to spin-dependent Fabry-Pe rot electron interference in the Cu film.

  18. The Effect of Spin-Dependent Donor Cluster Polarizabilities on the Magnetocapacitance of N-Type Silicon

    NASA Astrophysics Data System (ADS)

    New, David A.

    1984-06-01

    Magnetocapacitance studies have been employed to determine the variation of the donor polarizability contribution to the dielectric constant in n-type silicon with magnetic field, temperature, and donor concentration. Silicon samples with phosphorus concentrations ranging from 9 x 10('16)/cc to 1.0 x 10('18)/cc, as well as Si:As samples with 1.4 x 10('17)donors/cc and 2.5 x 10('18)donors/cc, were studied in the temperature range from 30 mK to 4.2 K at fields up to 19 tesla. Experimental results show the donor contribution varying as B('2) at low fields and B('n) at high fields, with n varying with concentration between .5 and 1.2. The low-field region shows a 1/T('n) dependence with n ranging from 1 to 3, with a much weaker temperature dependence at high fields. The magnitude of the field dependence is larger than expected for diamagnetic effects, isotropic, and smaller in Si:As than in Si:P at comparable concentrations, fields, and temperatures. A donor pair model, utilising spin-dependent polarizabilities, is presented which predicts a low-field (B/T)('2) region, weakening temperature dependence as the field increases, and high-field behavior determined by cluster diamagnetic effects. The calculation is extended to clusters of three donors. The question of donor cluster statistics has been studied using ESR donor cluster spectra in Si:P (3 x 10('16)/cc < N(,D) < 4.8 x 10('17)/cc) and Si:As (1.4 x 10('17)/cc < N(,D) < 1.0 x 10('18)/cc). The ratio of the integrated intensity of the outer hyperfine lines to the total integrated intensity is found to vary exponentially with donor concentration, consistent with the predictions of Poisson statistics. By partitioning a system of computer generated donors, requiring each donor in a cluster interact "strongly" with at least one other donor in the cluster, topological and cluster -cluster interaction effects are explored. Results of ESR studies allow explicit results to be calculated from the cluster polarizability

  19. First-principles study of spin-dependent thermoelectric properties of half-metallic Heusler thin films between platinum leads

    NASA Astrophysics Data System (ADS)

    Comtesse, Denis; Geisler, Benjamin; Entel, Peter; Kratzer, Peter; Szunyogh, László

    2014-03-01

    The electronic and magnetic bulk properties of half-metallic Heusler alloys such as Co2FeSi,Co2FeAl, Co2MnSi, and Co2MnAl are investigated by means of ab initio calculations in combination with Monte Carlo simulations. The electronic structure is analyzed using the plane-wave code quantum espresso and the magnetic exchange interactions are determined using the Korringa-Kohn-Rostoker (KKR) method. From the magnetic exchange interactions, the Curie temperature is obtained via Monte Carlo simulations. In addition, electronic transport properties of trilayer systems consisting of two semi-infinite platinum leads and a Heusler layer in-between are obtained from the fully relativistic screened KKR method by employing the Kubo-Greenwood formalism. The focus is on thermoelectric properties, namely, the Seebeck effect and its spin dependence. It turns out that already thin Heusler layers provide highly spin-polarized currents. This is attributed to the recovery of half-metallicity with increasing layer thickness. The absence of electronic states of spin-down electrons around the Fermi level suppresses the contribution of this spin channel to the total conductance, which strongly influences the thermoelectric properties and results in a spin polarization of thermoelectric currents.

  20. Spin-dependent constraints on blind spots for thermal singlino-higgsino dark matter with(out) light singlets

    NASA Astrophysics Data System (ADS)

    Badziak, Marcin; Olechowski, Marek; Szczerbiak, Paweł

    2017-07-01

    The LUX experiment has recently set very strong constraints on spin-independent interactions of WIMP with nuclei. These null results can be accommodated in NMSSM provided that the effective spin-independent coupling of the LSP to nucleons is suppressed. We investigate thermal relic abundance of singlino-higgsino LSP in these so-called spin-independent blind spots and derive current constraints and prospects for direct detection of spin-dependent interactions of the LSP with nuclei providing strong constraints on parameter space. We show that if the Higgs boson is the only light scalar the new LUX constraints set a lower bound on the LSP mass of about 300 GeV except for a small range around the half of Z 0 boson masses where resonant annihilation via Z 0 exchange dominates. XENON1T will probe entire range of LSP masses except for a tiny Z 0-resonant region that may be tested by the LZ experiment. These conclusions apply to general singlet-doublet dark matter annihilating dominantly to t\\overline{t} . Presence of light singlet (pseudo)scalars generically relaxes the constraints because new LSP (resonant and non-resonant) annihilation channels become important. Even away from resonant regions, the lower limit on the LSP mass from LUX is relaxed to about 250 GeV while XENON1T may not be sensitive to the LSP masses above about 400 GeV.

  1. Spin-dependent tunneling junctions with AlN and AlON barriers

    NASA Astrophysics Data System (ADS)

    Sharma, Manish; Nickel, Janice H.; Anthony, Thomas C.; Wang, Shan X.

    2000-10-01

    We report on ferromagnetic spin-dependent tunneling (SDT) junctions with NiFe/AlN/NiFe and NiFe/AlON/NiFe structures. Good barriers were formed by plasma nitridation and oxy-nitridation of Al films. Tunneling magnetoresistance ratios (TMR) up to 18% were observed at room temperature. The devices exhibit lower resistance-area products than those seen in reference junctions with Al2O3 barriers. The degradation in TMR at higher bias voltages is found to be less than that found in standard alumina junctions. AlN and AlON could thus be alternate materials for the tunnel barrier in SDT junctions.

  2. Constraints on spin-dependent parton distributions at large x from global QCD analysis

    DOE PAGES

    Jimenez-Delgado, P.; Avakian, H.; Melnitchouk, W.

    2014-09-28

    This study investigate the behavior of spin-dependent parton distribution functions (PDFs) at large parton momentum fractions x in the context of global QCD analysis. We explore the constraints from existing deep-inelastic scattering data, and from theoretical expectations for the leading x → 1 behavior based on hard gluon exchange in perturbative QCD. Systematic uncertainties from the dependence of the PDFs on the choice of parametrization are studied by considering functional forms motivated by orbital angular momentum arguments. Finally, we quantify the reduction in the PDF uncertainties that may be expected from future high-x data from Jefferson Lab at 12 GeV.

  3. {sup 3}He Spin-Dependent Cross Sections and Sum Rules

    SciTech Connect

    Slifer, K.; Auerbach, L.; Choi, Seonho; Incerti, S.; Lakuriqi, E.; Meziani, Z.-E.; Amarian, M.; Ketikyan, A.; Voskanian, H.; Averett, T.; Berthot, J.; Bertin, P.; DiSalvo, R.; Fonvieille, H.; Laveissiere, G.; Roblin, Y.

    2008-07-11

    We present a measurement of the spin-dependent cross sections for the {sup 3}He-vector (e-vector,e{sup '})X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1{<=}Q{sup 2}{<=}0.9 GeV{sup 2}. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.

  4. Spin-dependent Electron Correlations of a System with Broken Spin Symmetry

    NASA Astrophysics Data System (ADS)

    Yi, K. S.; Kim, J. I.; Kim, J. S.

    2001-04-01

    The spin-dependent local field corrections Gσ, σ'/ (q, ω) of a spin-polarized electron gas(SPEG) are examined within a genralized RPA. Numerical results of Gσ, σ/ (q, 0) for both the majority and minority spin electrons of SPEG show a complicated but interesting behavior as one varies the spin polarization ζ of the SPEG. A pronounced maximum in Gσ, σ/ (q, 0) is observed and the location of the peaks are found to depend strongly on the values of ζ. We also show some numerical results of the mixed susceptibilities χem and χme, which are finite and not identical in SPEG.

  5. Study of magnetic properties of spin-dependent Falicov-Kimball model on a triangular lattice

    NASA Astrophysics Data System (ADS)

    Kumar, Sant; Yadav, Umesh K.; Maitra, Tulika; Singh, Ishwar

    2013-02-01

    Numerical diagonalization technique and Monte-Carlo simulation algorithm is used to study the ground state properties of spin-dependent Falicov-Kimball model (FKM) on a triangular lattice for 1/3 filling of itinerant (d) and localized (f) electrons. We have found that the ground state configurations are of long range Neel ordered antiferromagnetic, ferromagnetic or mixture of anti-ferromagnetic and ferromagnetic type for different values of exchange correlation (J). The magnetization of d and f-electrons increases with increasing the exchange correlation (J) between d and f-electrons and then decreases with further increasing the value of J.

  6. Spin Dependent Ligand Binding Reactions of Iron-Containing Complexes and Proteins

    NASA Astrophysics Data System (ADS)

    Ozkanlar, Abdullah

    (Bio)chemical reactions in which the total electronic spin of the reactants is different from that of the product(s) are called spin-forbidden. Spin forbidden reactions involve spin transitions that only take place via an allowing mechanism, namely spin-orbit coupling. Such spin transitions are believed to take place, with greater probability, at the minimum energy crossing point (MECP) between two interacting spin-dependent potential energy surfaces. Spin forbidden reactions involving iron containing complexes have been studied to understand the role of reactant and product spin degrees of freedom on the reaction rates. The rate constants have been predicted by means of non-adiabatic transition state theory (NATST). We have implemented an ab-initio based computational methodology to predict rate constants of spin forbidden reactions. The relevant MECPs for the reactions studied here have been reported. In order to understand the role of spin transitions on reaction rates, we have studied the spin forbidden binding of singlet carbon monoxide, CO(S=0), singlet dihydrogen, H2(S=0), and singlet ethylene, C2H 4(S=0), to triplet iron tetracarbonyl, Fe(CO)4(S=1), each of which involves one spin transition from triplet to singlet states. The 300K rate constant predicted for CO binding to Fe(CO)4 is ˜ 10-13 cm3s-1molecule-1 , in agreement with the experimental value to within one order of magnitude. The temperature dependent rate constants computed for H2 binding to Fe(CO)4 are ˜ 10-14 cm3s -1molecule-1 showing a trend of faster rate with increasing temperature, in good agreement with the experimental values of 1.97x10 -14 cm3s-1molecule-1 and 2.47x10-14 cm3s-1molecule -1 for 296.5K and 315K, respectively, suggesting that spin transitions play important roles on the rates of this reaction. Finally, the 300K rate constant computed for C2H4 binding to Fe(CO)4 is ˜ 10-13 cm3s-1molecule -1, in good agreement with the experimental value of ˜ 10 -13 cm3s-1molecule-1 also

  7. Spin-dependent Seebeck effect and spin caloritronics in magnetic graphene

    NASA Astrophysics Data System (ADS)

    Rameshti, Babak Zare; Moghaddam, Ali G.

    2015-04-01

    We investigate the spin-dependent thermoelectric effects in magnetic graphene in both diffusive and ballistic regimes. Employing the Boltzmann and Landauer formalisms we calculate the spin and charge Seebeck coefficients (thermopower) in magnetic graphene varying the spin splitting, temperature, and doping of the junction. It is found that while in normal graphene the temperature gradient drives a charge current, in the case of magnetic graphene a significant spin current is also established. In particular we show that in the undoped magnetic graphene in which different spin carriers belong to conduction and valence bands, a pure spin current is driven by the temperature gradient. In addition it is revealed that profound thermoelectric effects can be achieved at intermediate easily accessible temperatures when the thermal energy is comparable with Fermi energy kBT ≲μ . By further investigation of the spin-dependent Seebeck effect and a significantly large figure of merit for spin thermopower ZspT , we suggest magnetic graphene as a promising material for spin-caloritronics studies and applications.

  8. The magnetism and spin-dependent electronic transport properties of boron nitride atomic chains

    NASA Astrophysics Data System (ADS)

    An, Yipeng; Zhang, Mengjun; Wu, Dapeng; Fu, Zhaoming; Wang, Tianxing; Jiao, Zhaoyong; Wang, Kun

    2016-07-01

    Very recently, boron nitride atomic chains were successively prepared and observed in experiments [O. Cretu et al., ACS Nano 8, 11950 (2015)]. Herein, using a first-principles technique, we study the magnetism and spin-dependent electronic transport properties of three types of BN atomic chains whose magnetic moment is 1 μB for BnNn-1, 2 μB for BnNn, and 3 μB for BnNn+1 type atomic chains, respectively. The spin-dependent electronic transport results demonstrate that the short BnNn+1 chain presents an obvious spin-filtering effect with high spin polarization ratio (>90%) under low bias voltages. Yet, this spin-filtering effect does not occur for long BnNn+1 chains under high bias voltages and other types of BN atomic chains (BnNn-1 and BnNn). The proposed short BnNn+1 chain is predicted to be an effective low-bias spin filters. Moreover, the length-conductance relationships of these BN atomic chains were also studied.

  9. Spin-dependent Seebeck effects in a graphene superlattice p–n junction with different shapes

    NASA Astrophysics Data System (ADS)

    Zhou, Benhu; Zhou, Benliang; Yao, Yagang; Zhou, Guanghui; Hu, Ming

    2017-10-01

    We theoretically calculate the spin-dependent transmission probability and spin Seebeck coefficient for a zigzag-edge graphene nanoribbon p–n junction with periodically attached stubs under a perpendicular magnetic field and a ferromagnetic insulator. By using the nonequilibrium Green’s function method combining with the tight-binding Hamiltonian, it is demonstrated that the spin-dependent transmission probability and spin Seebeck coefficient for two types of superlattices can be modulated by the potential drop, the magnetization strength, the number of periods of the superlattice, the strength of the perpendicular magnetic field, and the Anderson disorder strength. Interestingly, a metal to semiconductor transition occurs as the number of the superlattice for a crossed superlattice p–n junction increases, and its spin Seebeck coefficient is much larger than that for the T-shaped one around the zero Fermi energy. Furthermore, the spin Seebeck coefficient for crossed systems can be much pronounced and their maximum absolute value can reach 528 μV K-1 by choosing optimized parameters. Besides, the spin Seebeck coefficient for crossed p–n junction is strongly enhanced around the zero Fermi energy for a weak magnetic field. Our results provide theoretical references for modulating the thermoelectric properties of a graphene superlattice p–n junction by tuning its geometric structure and physical parameters.

  10. Time domain measurement of spin-dependent recombination - A novel defect spectroscopy method

    NASA Astrophysics Data System (ADS)

    Boehme, Christoph; Kanschat, Peter; Lips, Klaus

    2002-01-01

    A new defect characterization method is suggested which we call Time Domain Measurement of Spin-Dependent Recombination (TSR). Time resolved spin-dependent recombination rate changes in a semiconductor that is exposed to a strong magnetic field are measured. These rate changes are triggered by a spin resonant excitation of recombination centers and charge carriers through short and intensive microwave pulses. The coherence of the charge carrier-recombination center pair ensemble is already destroyed during the pulse by fast recombination processes of the recombining pairs. After the pulse, a slow relaxation of the recombination rate into its steady state takes place which is caused by the dissociation of the recombination partners. Unlike Electrically Detected Magnetic Resonance (EDMR) which can only detect and quantify distinct recombination centers, TSR opens access to a variety of qualitative and quantitative information about electronically active defects due to the dependence of the signal transient on the various parameters. Particularly because of the possibility to measure recombination probabilities of distinct recombination paths directly, TSR could be a promising new approach to defect spectroscopy. The feasibility of TSR is demonstrated with the dangling bond recombination path of microcrystalline silicon.

  11. Exploration of Defects in 4H-SiC MOSFETs via Spin Dependent Charge Pumping

    NASA Astrophysics Data System (ADS)

    Anders, Mark; Lenahan, Patrick; Lelis, Aivars

    4H-SiC MOSFETs have great promise for use in high temperature and high voltage applications. Unfortunately, defects at the SiC/SiO2 interface reduce the performance of these devices. Previously, our group utilized electrically detected magnetic resonance (EDMR) detected via spin dependent recombination (SDR) to identify such SiC/SiO2 interface defects utilizing the bipolar amplification (BAE) biasing scheme; we observed SiC silicon vacancies, E-prime centers, and hydrogen complexed E-prime centers. All of these defects must have levels around the middle of the SiC band gap because they are effective recombination centers. We expanded our studies to include EDMR detection via spin dependent charge pumping (SDCP) at low field, X band, and K band, allowing EDMR exploration of nearly the entire 4H-SiC band gap. Perhaps the most important finding of the (nearly) full band gap measurements is the absence of the carbon dangling bond spectrum in the SDCP. Additionally, in nMOSFETs, we observe an SDCP EDMR spectrum dominated by a silicon vacancy, whereas in pMOSFETs, we also observe a strong, nearly isotropic single line spectrum with g = 2.00244 and 2.00248 when the c-axis is nearly parallel and perpendicular to the magnetic field, respectively. The results suggest that silicon vacancy centers dominate nMOSFET interfaces whereas additional defects clearly play important roles in pMOSFETs.

  12. Spin-dependent electron transport in a Rashba quantum wire with rough edges

    NASA Astrophysics Data System (ADS)

    Xiao, X. B.; Li, H. L.; Zhou, G. H.; Liu, N. H.

    2012-09-01

    We investigate theoretically the spin-dependent electron transport in a Rashba quantum wire with rough edges. The charge and spin conductances are calculated as function of the electron energy and wire length by adopting the spin-resolved lattice Green function method. For a single disordered Rashba wire, it is found that the charge conductance quantization is destroyed by the edge disorder. However, a nonzero spin conductance can be generated and its amplitude can be manipulated by varying the wire length, which is attributed to the broken structure symmetries and the spin-dependent quantum interference induced by the rough boundaries. For a large ensemble of disordered Rashba wires, the average charge conductance decreases monotonically, however, the average spin conductance increases to a maximum value and then decreases, with increasing wire length. Further study shows that the influence of the rough edges on the charge and spin conductances can be eliminated by applying a perpendicular magnetic field to the wire. In addition, a very large magnitude of the spin conductance can be achieved when the electron energy lies between the two thresholds of each pair of subbands. These findings may not only benefit to further apprehend the transport properties of the Rashba low-dimensional systems but also provide some theoretical instructions to the application of spintronics devices.

  13. Gap state charge induced spin-dependent negative differential resistance in tunnel junctions

    NASA Astrophysics Data System (ADS)

    Jiang, Jun; Zhang, X.-G.; Han, X. F.

    2016-04-01

    We propose and demonstrate through first-principles calculation a new spin-dependent negative differential resistance (NDR) mechanism in magnetic tunnel junctions (MTJ) with cubic cation disordered crystals (CCDC) AlO x or Mg1-x Al x O as barrier materials. The CCDC is a class of insulators whose band gap can be changed by cation doping. The gap becomes arched in an ultrathin layer due to the space charge formed from metal-induced gap states. With an appropriate combination of an arched gap and a bias voltage, NDR can be produced in either spin channel. This mechanism is applicable to 2D and 3D ultrathin junctions with a sufficiently small band gap that forms a large space charge. It provides a new way of controlling the spin-dependent transport in spintronic devices by an electric field. A generalized Simmons formula for tunneling current through junction with an arched gap is derived to show the general conditions under which ultrathin junctions may exhibit NDR.

  14. Spin-polarization and spin-dependent logic gates in a double quantum ring based on Rashba spin-orbit effect: Non-equilibrium Green's function approach

    SciTech Connect

    Eslami, Leila Esmaeilzadeh, Mahdi

    2014-02-28

    Spin-dependent electron transport in an open double quantum ring, when each ring is made up of four quantum dots and threaded by a magnetic flux, is studied. Two independent and tunable gate voltages are applied to induce Rashba spin-orbit effect in the quantum rings. Using non-equilibrium Green's function formalism, we study the effects of electron-electron interaction on spin-dependent electron transport and show that although the electron-electron interaction induces an energy gap, it has no considerable effect when the bias voltage is sufficiently high. We also show that the double quantum ring can operate as a spin-filter for both spin up and spin down electrons. The spin-polarization of transmitted electrons can be tuned from −1 (pure spin-down current) to +1 (pure spin-up current) by changing the magnetic flux and/or the gates voltage. Also, the double quantum ring can act as AND and NOR gates when the system parameters such as Rashba coefficient are properly adjusted.

  15. Anomalous organic magnetoresistance from competing carrier-spin-dependent interactions with localized electronic and nuclear spins

    NASA Astrophysics Data System (ADS)

    Flatté, Michael E.

    Transport of carriers through disordered electronic energy landscapes occurs via hopping or tunneling through various sites, and can enhance the effects of carrier spin dynamics on the transport. When incoherent hopping preserves the spin orientation of carriers, the magnetic-field-dependent correlations between pairs of spins influence the charge conductivity of the material. Examples of these phenomena have been identified in hopping transport in organic semiconductors and colloidal quantum dots, as well as tunneling through oxide barriers in complex oxide devices, among other materials. The resulting room-temperature magnetic field effects on the conductivity or electroluminescence require external fields of only a few milliTesla. These magnetic field effects can be dramatically modified by changes in the local spin environment. Recent theoretical and experimental work has identified a regime for low-field magnetoresistance in organic semiconductors in which the spin-relaxing effects of localized nuclear spins and electronic spins interfere1. The regime is studied experimentally by the controlled addition of localized electronic spins, through the addition of a stable free radical (galvinoxyl) to a material (MEH-PPV) that exhibits substantial room-temperature magnetoresistance (20 initially suppressed by the doping, as the localized electronic spin mixes one of the two spins whose correlation controls the transport. At intermediate doping, when one spin is fully decohered but the other is not, there is a regime where the magnetoresistance is insensitive to the doping level. For much greater doping concentrations the magnetoresistance is fully suppressed as both spins that control the charge conductivity of the material are mixed. The behavior is described within a theoretical model describing the effect of carrier spin dynamics on the current. Generalizations to amorphous and other disordered crystalline semiconductors will also be described. This work was supported by DOE and an ARO MURI and was done in collaboration with N. J. Harmon, K. Sahin-Tiras, Y. Wang and M. Wohlgenannt.

  16. Light-front spin-dependent spectral function and nucleon momentum distributions for a three-body system

    DOE PAGES

    Del Dotto, Alessio; Pace, Emanuele; Salme, Giovanni; ...

    2017-01-10

    Poincare covariant definitions for the spin-dependent spectral function and for the momentum distributions within the light-front Hamiltonian dynamics are proposed for a three-fermion bound system, starting from the light-front wave function of the system. The adopted approach is based on the Bakamjian–Thomas construction of the Poincaré generators, which allows one to easily import the familiar and wide knowledge on the nuclear interaction into a light-front framework. The proposed formalism can find useful applications in refined nuclear calculations, such as those needed for evaluating the European Muon Collaboration effect or the semi-inclusive deep inelastic cross sections with polarized nuclear targets, sincemore » remarkably the light-front unpolarized momentum distribution by definition fulfills both normalization and momentum sum rules. As a result, also shown is a straightforward generalization of the definition of the light-front spectral function to an A-nucleon system.« less

  17. Magnetoelectric coupling and spin-dependent tunneling in Fe/PbTiO{sub 3}/Fe multiferroic heterostructure with a Ni monolayer inserted at one interface

    SciTech Connect

    Dai, Jian-Qing Zhang, Hu; Song, Yu-Min

    2015-08-07

    We report on first-principles calculations of a Ni monolayer inserted at one interface in the epitaxial Fe/PbTiO{sub 3}/Fe multiferroic heterostructure, focusing on the magnetoelectric coupling and the spin-dependent transport properties. The results of magnetoelectric coupling calculations reveal an attractive approach to realize cumulative magnetoelectric effects in the ferromagnetic/ferroelectric/ferromagnetic superlattices. The underlying physics is attributed to the combinations of several different magnetoelectric coupling mechanisms such as interface bonding, spin-dependent screening, and different types of magnetic interactions. We also demonstrate that inserting a Ni monolayer at one interface in the Fe/PbTiO{sub 3}/Fe multiferroic tunnel junction is an efficient method to produce considerable tunneling electroresistance effect by modifying the tunnel potential barrier and the interfacial electronic structure. Furthermore, coexistence of tunneling magnetoresistance and tunneling electroresistance leads to the emergence of four distinct resistance states, which can be served as a multistate-storage device. The complicated influencing factors including bulk properties of the ferromagnetic electrodes, decay rates of the evanescent states in the tunnel barrier, and the specific interfacial electronic structure provide us promising opportunities to design novel multiferroic tunnel junctions with excellent performances.

  18. Time-resolved spin-dependent processes in magnetic field effects in organic semiconductors

    NASA Astrophysics Data System (ADS)

    Peng, Qiming; Li, Xianjie; Li, Feng

    2012-12-01

    We investigated the time-resolved magnetic field effects (MFEs) in tri-(8-hydroxyquinoline)-aluminum (Alq3) based organic light-emitting diodes (OLEDs) through the transient electroluminescence (EL) method. The values of magneto-electroluminescence (MEL) decrease with the time, and the decreasing slope is proportional to the driving voltage. Specifically, negative MELs are seen when the driving voltage is high enough (V > 11 V). We propose a model to elucidate the spin-dependent processes and theoretically simulate the time-resolved MELs. In particular, this dynamic analysis of time-resolved MELs reveals that the intersystem crossing between singlet and triplet electron-hole pairs and the triplet-triplet annihilation are responsible for the time-resolved MELs at the beginning and enduring periods of the pulse, respectively.

  19. Picasso:. Search for Dark Matter in the Spin-Dependent Sector

    NASA Astrophysics Data System (ADS)

    Piro, M.-C.

    2011-06-01

    The PICASSO project is using superheated droplets of C4F10 for the direct detection of Dark Matter candidates in the spin-dependent (SD) sector. The total setup includes 32 detectors installed in the SNOLAB underground laboratory in Sudbury (Ontario, Canada). The present level of sensitivity is at 0.16 pb on protons at 90% C.L. (MW= 24GeV/c2) following an analysis of two detectors only. A concentrated effort in detector purification and a new fabrication procedure allowed an additional background reduction of about a factor of ten. In order to increase the sensitivity of the detectors, new discrimination tools were developed to distinguish between WIMP induced nuclear recoils and alpha decay background. We report preliminary results where an alpha background rejection of 80% could be achieved in the region where WIMP induced nuclear recoils are expected.

  20. Charge and spin-dependent thermal efficiency of polythiophene molecular junction in presence of dephasing

    NASA Astrophysics Data System (ADS)

    Golsanamlou, Z.; M. Bagheri, Tagani; H. Rahimpour, Soleimani

    2015-10-01

    The charge and spin-dependent thermoelectric properties of different lengths of polythiophene in a molecular junction are investigated using the Büttiker probe method within Green function formalism in linear response regime. The coupling of the molecular chain to three-dimensional ferromagnetic electrodes is described by a tight-binding model for both parallel and antiparallel spin configurations. The decrease of height of transmission probability peaks and thermoelectric coefficients are observed in the presence of the Büttiker probes. The reduction is more intensive in the strong dephased chains. Results show that the spin magnetothermopower is bigger than the charge magnetothermopower due to the larger difference between the spin thermopowers with respect to the charge ones. In addition, we observed that the kind of carriers participating in the thermoelectric transport depends on the number of the thiophene rings.

  1. Controlling spin-dependent tunneling by bandgap tuning in epitaxial rocksalt MgZnO films

    SciTech Connect

    Li, D. L.; Ma, Q. L.; Wang, S. G.; Ward, R. C. C.; Hesjedal, T.; Zhang, X. -G.; Kohn, A.; Amsellem, E.; Yang, G.; Liu, J. L.; Jiang, J.; Wei, H. X.; Han, X. F.

    2014-12-02

    Widespread application of magnetic tunnel junctions (MTJs) for information storage has so far been limited by the complicated interplay between tunnel magnetoresistance (TMR) ratio and the product of resistance and junction area (RA). An intricate connection exists between TMR ratio, RA value and the bandgap and crystal structure of the barrier, a connection that must be unravelled to optimise device performance and enable further applications to be developed. In this paper, we demonstrate a novel method to tailor the bandgap of an ultrathin, epitaxial Zn-doped MgO tunnel barrier with rocksalt structure. This structure is attractive due to its good Δ1 spin filtering effect, and we show that MTJs based on tunable MgZnO barriers allow effective balancing of TMR ratio and RA value. Finally, in this way spin-dependent transport properties can be controlled, a key challenge for the development of spintronic devices.

  2. Controlling spin-dependent tunneling by bandgap tuning in epitaxial rocksalt MgZnO films

    DOE PAGES

    Li, D. L.; Ma, Q. L.; Wang, S. G.; ...

    2014-12-02

    Widespread application of magnetic tunnel junctions (MTJs) for information storage has so far been limited by the complicated interplay between tunnel magnetoresistance (TMR) ratio and the product of resistance and junction area (RA). An intricate connection exists between TMR ratio, RA value and the bandgap and crystal structure of the barrier, a connection that must be unravelled to optimise device performance and enable further applications to be developed. In this paper, we demonstrate a novel method to tailor the bandgap of an ultrathin, epitaxial Zn-doped MgO tunnel barrier with rocksalt structure. This structure is attractive due to its good Δ1more » spin filtering effect, and we show that MTJs based on tunable MgZnO barriers allow effective balancing of TMR ratio and RA value. Finally, in this way spin-dependent transport properties can be controlled, a key challenge for the development of spintronic devices.« less

  3. Spin-dependent recombination involving oxygen-vacancy complexes in silicon

    NASA Astrophysics Data System (ADS)

    Franke, David P.; Hoehne, Felix; Vlasenko, Leonid S.; Itoh, Kohei M.; Brandt, Martin S.

    2014-05-01

    Spin-dependent relaxation and recombination processes in γ-irradiated n-type Czochralski-grown silicon are studied using continuous wave (cw) and pulsed electrically detected magnetic resonance (EDMR). Two processes involving the SL1 center, the neutral excited triplet state of the oxygen-vacancy complex, are observed which can be separated by their different dynamics. One of the processes is the relaxation of the excited SL1 state to the ground state of the oxygen-vacancy complex, the other a charge transfer between 31P donors and SL1 centers forming close pairs, as indicated by electrically detected electron double resonance. For both processes, the recombination dynamics is studied with pulsed EDMR techniques. We demonstrate the feasibility of true zero-field cw and pulsed EDMR for spin-1 systems and use this to measure the lifetimes of the different spin states of SL1 also at vanishing external magnetic field.

  4. The spin-dependent transport properties of zigzag α-graphyne nanoribbons and new device design

    PubMed Central

    Ni, Yun; Wang, Xia; Tao, Wei; Zhu, Si-Cong; Yao, Kai-Lun

    2016-01-01

    By performing first-principle quantum transport calculations, we studied the electronic and transport properties of zigzag α-graphyne nanoribbons in different magnetic configurations. We designed the device based on zigzag α-graphyne nanoribbon and studied the spin-dependent transport properties, whose current-voltage curves show obvious spin-polarization and conductance plateaus. The interesting transport behaviours can be explained by the transport spectra under different magnetic configurations, which basically depends on the symmetry matching of the electrodes’ bandstructures. Simultaneously, spin Seebeck effect is also found in the device. Thus, according to the transport behaviours, zigzag α-graphyne nanoribbons can be used as a dual spin filter diode, a molecule signal converter and a spin caloritronics device, which indicates that α-graphyne is a promising candidate for the future application in spintronics. PMID:27180808

  5. Controlling spin-dependent tunneling by bandgap tuning in epitaxial rocksalt MgZnO films

    PubMed Central

    Li, D. L.; Ma, Q. L.; Wang, S. G.; Ward, R. C. C.; Hesjedal, T.; Zhang, X.-G.; Kohn, A.; Amsellem, E.; Yang, G.; Liu, J. L.; Jiang, J.; Wei, H. X.; Han, X. F.

    2014-01-01

    Widespread application of magnetic tunnel junctions (MTJs) for information storage has so far been limited by the complicated interplay between tunnel magnetoresistance (TMR) ratio and the product of resistance and junction area (RA). An intricate connection exists between TMR ratio, RA value and the bandgap and crystal structure of the barrier, a connection that must be unravelled to optimise device performance and enable further applications to be developed. Here, we demonstrate a novel method to tailor the bandgap of an ultrathin, epitaxial Zn-doped MgO tunnel barrier with rocksalt structure. This structure is attractive due to its good Δ1 spin filtering effect, and we show that MTJs based on tunable MgZnO barriers allow effective balancing of TMR ratio and RA value. In this way spin-dependent transport properties can be controlled, a key challenge for the development of spintronic devices. PMID:25451163

  6. The nonsinglet spin-dependent structure function evolution by Laplace and characteristics methods

    SciTech Connect

    Boroun, G. R. E-mail: boroun@razi.ac.ir; Zarrin, S.; Dadfar, S.

    2016-03-15

    We evaluate the non-singlet spin-dependent structure function g{sub 1}{sup NS} at leading order (LO) and next-to-leading order (NLO) by using the Laplace-transform technique and method of characteristics and also obtain its first moment at NLO. The polarized non-singlet structure function results are compared with the data from HERMES (A. Airapetian et al., Phys. Rev. D 75, 012007 (2007)) and E143 (K. Abe et al. (E143 Collab.), Phys. Rev. D 58, 112003 (1998)) at LO and NLO analyses and the first-moment the result at NLO is compared with the result of the NLO GRSV2000 fit. Considering the solution, this method is valid at low- and large-x regions.

  7. Spin-dependent inelastic collisions in spin-2 Bose-Einstein condensates

    SciTech Connect

    Tojo, Satoshi; Hayashi, Taro; Tanabe, Tatsuyoshi; Hirano, Takuya; Kawaguchi, Yuki; Saito, Hiroki; Ueda, Masahito

    2009-10-15

    We studied spin-dependent two-body inelastic collisions in F=2 {sup 87}Rb Bose-Einstein condensates both experimentally and theoretically. The {sup 87}Rb condensates were confined in an optical trap and selectively prepared in various spin states in the F=2 manifold at a magnetic field of 3.0 G. The measured atom loss rates depend on the spin states of colliding atoms. We measured two fundamental loss coefficients for two-body inelastic collisions with total spins of 0 and 2. The loss coefficients determine the loss rates of all the spin pairs. The experimental results for mixtures of all spin combinations are in good agreement with numerical solutions of the Gross-Pitaevskii equations that include the effect of a magnetic field gradient.

  8. The spin-dependent transport properties of zigzag α-graphyne nanoribbons and new device design.

    PubMed

    Ni, Yun; Wang, Xia; Tao, Wei; Zhu, Si-Cong; Yao, Kai-Lun

    2016-05-16

    By performing first-principle quantum transport calculations, we studied the electronic and transport properties of zigzag α-graphyne nanoribbons in different magnetic configurations. We designed the device based on zigzag α-graphyne nanoribbon and studied the spin-dependent transport properties, whose current-voltage curves show obvious spin-polarization and conductance plateaus. The interesting transport behaviours can be explained by the transport spectra under different magnetic configurations, which basically depends on the symmetry matching of the electrodes' bandstructures. Simultaneously, spin Seebeck effect is also found in the device. Thus, according to the transport behaviours, zigzag α-graphyne nanoribbons can be used as a dual spin filter diode, a molecule signal converter and a spin caloritronics device, which indicates that α-graphyne is a promising candidate for the future application in spintronics.

  9. Spin-dependent tunneling time in periodic diluted-magnetic-semiconductor/nonmagnetic-barrier superlattices

    SciTech Connect

    Yang, Ping-Fan; Guo, Yong

    2016-02-01

    We investigate the tunneling time (dwell time) in periodic diluted-magnetic-semiconductor/nonmagnetic-barrier (DMS/NB) superlattices subjected to an external magnetic field. It is found that spin-dependent resonant bands form in the spectra of dwell time, which can be effectively manipulated by not only the external magnetic field but also the geometric parameters of the system. Moreover, an intuitive semiclassical delay is defined to illustrate the behavior of the dwell time, and the former one is shown to be the result of “smoothing out” the latter one. We also find that the dwell time in diluted-magnetic-semiconductor/semiconductor superlattices behaves surprisingly different from the DMS/NB case, especially for spin-down electrons.

  10. Spin-dependent coupling between quantum dots and topological quantum wires

    NASA Astrophysics Data System (ADS)

    Hoffman, Silas; Chevallier, Denis; Loss, Daniel; Klinovaja, Jelena

    2017-07-01

    Considering Rashba quantum wires with a proximity-induced superconducting gap as physical realizations of Majorana bound states and quantum dots, we calculate the overlap of the Majorana wave functions with the local wave functions on the dot. We determine the spin-dependent tunneling amplitudes between these two localized states and show that we can tune into a fully spin polarized tunneling regime by changing the distance between dot and Majorana bound state. Upon directly applying this to the tunneling model Hamiltonian, we calculate the effective magnetic field on the quantum dot flanked by two Majorana bound states. The direction of the induced magnetic field on the dot depends on the occupation of the nonlocal fermion formed from the two Majorana end states which can be used as a readout for such a Majorana qubit.

  11. Spin-Dependent Goos-Hanchen Effect in Semiconducting Quantum Dots

    NASA Astrophysics Data System (ADS)

    Abdelrazek, Ahmed S.; Zein, Walid A.; Phillips, Adel H.

    2013-08-01

    The present research is devoted to the investigation of the spin-dependant Goos-Hanchen phase shift in quantum nanodevice. This nanodevice is modeled as semiconducting quantum dot coupled to two ferromagnetic leads. The spin transport through such nanodevice is conducted under the effect of both magnetic field and the photon energy of the induced ac-field. The angle of incidence of electrons is taken into account. Results show that the Goos-Hanchen phase shift of spin-up electrons is different from that of spin-down electron. Also, spin polarization and giant magneto-resistance are strongly depending on the angle of incidence of electrons and the photon energy of the induced ac-field. The present model could realize experimentally the spin beam splitter and spin filter needed for spin qubits and quantum information processing.

  12. Spin-dependent quasiparticle reflection and bound States at interfaces with itinerant antiferromagnets.

    PubMed

    Bobkova, I V; Hirschfeld, P J; Barash, Yu S

    2005-01-28

    We find a novel channel of quasiparticle reflection from the simplest two-sublattice antiferromagnet (AF) on a bipartite lattice. Low-energy quasiparticles in a normal metal (N) experience spin-dependent retroreflection at AF/N interfaces. As a combined effect of antiferromagnetic and Andreev reflections, subgap Andreev states arise at an AF/superconductor (SC) interface. When the antiferromagnetic reflection dominates the specular one, Andreev bound states have almost zero energy on AF/s-wave superconductor (sSC) interfaces, whereas there are no low-energy subgap states on AF/d-wave superconductor (dSC) boundaries. For an sSC/AF/sSC junction, the bound states are found to split, due to the finite width of the AF interlayer, and carry the supercurrent. The theory developed in the present Letter is based on a novel quasiclassical approach, which applies to interfaces involving itinerant antiferromagnets.

  13. Spin-dependent electron momentum density in the Ni2MnSn Heusler alloy

    NASA Astrophysics Data System (ADS)

    Deb, Aniruddha; Hiraoka, N.; Itou, M.; Sakurai, Y.; Onodera, M.; Sakai, N.

    2001-05-01

    The spin-dependent electron momentum distribution in Ni2MnSn Heusler alloy single crystals was studied using 270 keV circularly polarized synchrotron radiation, through magnetic Compton profile measurements, on the high energy inelastic scattering beamline at SPring-8. The experiments were carried out for the three principal crystallographic directions [100], [110], and [111] at 10 K. The results show that the conduction electrons have a negative spin polarization of 0.34μB the 3d spin moment on the nickel site was found to be negligible. A band structure calculation was performed including a hyperfine field study using the full potential linearized augmented plane wave (FLAPW) method, with the generalized gradient approximation (GGA) for the electronic exchange and correlation. The spin moment on the Mn site at 10 K was observed as 4.39μB. The spin-dependent Compton profiles for the [100], [110], and [111] directions reported here show anisotropy in the momentum density, which is in good agreement with the FLAPW-GGA results, based on a ferromagnetic ground state. The hyperfine fields calculated were compared with previously calculated hyperfine field of Cu2MnAl and Co2FeGa Heusler alloys. From the comparison it is seen that the value of Hval (valence contribution to the hyperfine field) is roughly proportional to the spin polarization (ms) of the s electrons at the X (Ni,Cu,Co) and Y (Mn of Ni2MnSn and Cu2MnAl, Fe of Co2FeGa) atom positions.

  14. Nuclear Spin Dependent Chemistry of the Trihydrogen Cation in Diffuse Interstellar Clouds

    NASA Astrophysics Data System (ADS)

    Crabtree, Kyle

    2015-05-01

    The trihydrogen cation, H3+,long thought to be the species responsible for initiating ion-molecule chemistry in the interstellar medium, was first observed in interstellar clouds twenty years ago. Since its detection, this cation has been used to infer temperatures, densities, cloud sizes, and the local cosmic ray ionization rate. However, in diffuse molecular clouds the excitation temperature of its two nuclear spin modifications, ortho (I = 3 / 2) and para-H3+(I = 1 / 2) is found to differ markedly from the cloud kinetic temperature inferred from the spin modifications of molecular hydrogen (H2) in the same environment. A steady state analysis of the chemical kinetics of ortho and para-H3+suggests that the interplay of thermalizing collisions with H2 and nuclear spin dependent dissociative recombination with electrons may result in a nonthermal excitation temperature. Each of these processes is complex. Collisions between H3+and H2 must obey selection rules based on conservation of nuclear spin angular momentum, and the allowed spin conversion reactions, which proceed through the fluxional (H5+)* intermediate, each have different statistical weights and energetic requirements. Meanwhile, theoretical and experimental studies of H3+electron recombination carried out over the past 40 years have yielded rates that span 4 orders of magnitude in range. We will present experimental measurements of the nuclear spin dependence of the reactions of H3+with H2 and with electrons, as well as astronomical observations of H3+in diffuse molecular clouds and time-dependent chemical modeling of these environments. Astrochemical models incorporating the latest experimental data still do not satisfactorily explain the observed excitation temperature in diffuse molecular clouds, and point to the need for state-selective measurements of the H3+electron recombination rate.

  15. Longitudinal spin separation of light and its performance in three-dimensionally controllable spin-dependent focal shift

    PubMed Central

    Liu, Sheng; Li, Peng; Zhang, Yi; Gan, Xuetao; Wang, Meirong; Zhao, Jianlin

    2016-01-01

    Spin Hall effect of light, which is normally explored as a transverse spin-dependent separation of a light beam, has attracted enormous research interests. However, it seems there is no indication for the existence of the longitudinal spin separation of light. In this paper, we propose and experimentally realize the spin separation along the propagation direction by modulating the Pancharatnam-Berry (PB) phase. Due to the spin-dependent divergence and convergence determined by the PB phase, a focused Gaussian beam could split into two opposite spin states, and focuses at different distances, representing the longitudinal spin separation. By combining this longitudinal spin separation with the transverse one, we experimentally achieve the controllable spin-dependent focal shift in three dimensional space. This work provides new insight on steering the spin photons, and is expected to explore novel applications of optical trapping, manipulating, and micromachining with higher degree of freedom. PMID:26882995

  16. Longitudinal spin separation of light and its performance in three-dimensionally controllable spin-dependent focal shift

    NASA Astrophysics Data System (ADS)

    Liu, Sheng; Li, Peng; Zhang, Yi; Gan, Xuetao; Wang, Meirong; Zhao, Jianlin

    2016-02-01

    Spin Hall effect of light, which is normally explored as a transverse spin-dependent separation of a light beam, has attracted enormous research interests. However, it seems there is no indication for the existence of the longitudinal spin separation of light. In this paper, we propose and experimentally realize the spin separation along the propagation direction by modulating the Pancharatnam-Berry (PB) phase. Due to the spin-dependent divergence and convergence determined by the PB phase, a focused Gaussian beam could split into two opposite spin states, and focuses at different distances, representing the longitudinal spin separation. By combining this longitudinal spin separation with the transverse one, we experimentally achieve the controllable spin-dependent focal shift in three dimensional space. This work provides new insight on steering the spin photons, and is expected to explore novel applications of optical trapping, manipulating, and micromachining with higher degree of freedom.

  17. Spin-dependent photophysics in polymers lightly doped with fullerene derivatives: Photoluminescence and electrically detected magnetic resonance

    NASA Astrophysics Data System (ADS)

    Zerai Tedlla, B.; Zhu, F.; Cox, M.; Koopmans, B.; Goovaerts, E.

    2015-02-01

    Lightly fullerene-doped polymers are suitable composite systems to study spin-dependent bimolecular interactions among charge excitations due to their long lifetimes in these systems. These interactions can affect the photocurrent as well as the open-circuit voltage in an organic solar cell. Combining photoluminescence detected magnetic resonance (PLDMR) and electrically detected magnetic resonance (EDMR) spectroscopies we study films and devices of poly(p -phenylene vinylene) polymers poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) and superyellow PPV (SY-PPV) lightly doped with various fullerene derivatives [6,6]-phenyl C61 butyric acid methyl ester (PCBM), bis[60]PCBM (bis-PCBM), indene-C60 bisadduct (ICBA), and [6,6]-phenyl C71 butyric acid methyl ester (PC70BM). (i) We demonstrate strong fullerene triplet exciton (TE) production in SY-PPV:fullerene blends, whereas this is absent in MDMO-PPV:PCBM and only very weak in MDMO-PPV:ICBA. The low TE production in blends with MDMO-PPV is attributed to a weaker singlet-singlet energy-transfer coupling and an unfavorable triplet level alignment between the blend components. (ii) The fullerene TE spectra are analyzed on the basis of a single type of triplet excitation in PCBM, bis-PCBM, and ICBA, and two triplet species in PC70BM which are attributed to the α- and β-type isomers of the latter molecule. (iii) The sign change with increasing temperature of the g ˜2 sharp central line in photo-EDMR, which is observed both in pristine SY-PPV and in blends with fullerene, is correlated to a transition from dominant TE-polaron annihilation to nongeminate polaron recombination processes.

  18. Development of new atomic scale defect identification schemes in micro / nanoelectronics incorporating digital signal processing methods for investigating zero/low field spin dependent transport and passage effects in electrically detected magnetic resonance

    NASA Astrophysics Data System (ADS)

    Cochrane, Corey J.

    This work focuses on the development of new techniques for the study of spin dependent transport and trapping centers in fully processed micro and nanoelectronics. The first, and most interesting, technique offers a very low cost means to study spin dependent transport in microelectronics as an alternative to electrically detected magnetic resonance (EDMR). EDMR measurements generally require strong static magnetic fields, typically 3 kG or greater, and high frequency oscillating electromagnetic fields, typically 9 GHz or higher. In this work, it is demonstrated that large spin dependent recombination and tunneling signals can be detected in the absence of the oscillating electromagnetic field at zero magnetic field. The physics behind this technique is based upon the mixing of singlet and triplet energy states of the electron spin pairs involved in the spin dependent processes. In this study, we show that this technique can be applied to Si and SiC based devices. Theoretically, it can be applicable to devices of all material systems in which defects play a role in spin dependent transport, some of which include CdTe and GaN. Although the resolution of the g value is sacrificed in this new measurement, the technique can detect electron-nuclear hyperfine interactions and possibly dipolar and exchange interactions. The technique also has great promise in microelectronic device reliability studies as it is directly applicable to time dependent dielectric breakdown in thin film dielectrics and bias temperature instabilities in transistors. Other applications of this new physics include self-calibrating magnetometers, spin based memories, quantum computation, and miniature EDMR spectrometers for wafer probing stations. The second technique involves the utilization of passage effects that arise when performing magnetic field modulation in EDMR. When certain conditions are met, the higher order harmonics of the spin dependent signal can contain much useful information

  19. Spin-dependent processes at the crystalline Si-SiO2 interface at high magnetic fields

    NASA Astrophysics Data System (ADS)

    McCamey, D. R.; Morley, G. W.; Seipel, H. A.; Brunel, L. C.; van Tol, J.; Boehme, C.

    2008-07-01

    An experimental study on the nature of spin-dependent excess charge-carrier transitions at the interface between (111)-oriented phosphorous-doped ([P]≈1015cm-3) crystalline silicon and silicon dioxide at high magnetic field (B0≈8.5T) is presented. Electrically detected magnetic-resonance (EDMR) spectra of the hyperfine split P31 donor-electron transitions and paramagnetic interface defects were conducted at temperatures in the range of 3K≤T≤12K . The results at these previously unattained (for EDMR) magnetic-field strengths reveal the dominance of spin-dependent processes that differ from the previously well investigated recombination between the P31 donor and the Pb state, which dominates at low magnetic fields. While magnetic resonant current responses due to P31 and Pb states are still present, they do not correlate and only the Pb contribution can be associated with an interface process due to spin-dependent tunneling between energetically and physically adjacent Pb states. This work provides an experimental demonstration of spin-dependent tunneling between physically adjacent and identical electronic states as proposed by Kane [Nature (London) 393, 133 (1998)] for readout of donor qubits.

  20. Edge-defect induced spin-dependent Seebeck effect and spin figure of merit in graphene nanoribbons.

    PubMed

    Liu, Qing-Bo; Wu, Dan-Dan; Fu, Hua-Hua

    2017-10-02

    By using the first-principle calculations combined with the non-equilibrium Green's function approach, we have studied spin caloritronic properties of graphene nanoribbons (GNRs) with different edge defects. The theoretical results show that the edge-defected GNRs with sawtooth shapes can exhibit spin-dependent currents with opposite flowing directions by applying temperature gradients, indicating the occurrence of the spin-dependent Seebeck effect (SDSE). The edge defects bring about two opposite effects on the thermal spin currents: the enhancement of the symmetry of thermal spin-dependent currents, which contributes to the realization of pure thermal spin currents, and the decreasing of the spin thermoelectric conversion efficiency of the devices. It is fortunate that applying a gate voltage is an efficient route to optimize these two opposite spin thermoelectric properties towards realistic device applications. Moreover, due to the existence of spin-splitting band gaps, the edge-defected GNRs can be designed as spin-dependent Seebeck diodes and rectifiers, indicating that the edge-defected GNRs are potential candidates for room-temperature spin caloritronic devices.

  1. Spin-dependent processes in silicon-rich silicon-nitride thin film solar cells

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Yun; Paik, Seoyoung; McCamey, Dane; Boehme, Christoph; Hu, Jian; Zhu, Feng; Madan, Arun

    2010-03-01

    Silicon-rich silicon-nitride (SiNx:H) is attracting attention due to its relevance for light emitting diodes, electrolytic devices and solar cells. Charge transport and recombination in this material are key factors for its optoelectronic properties. Since SiNx:H is highly disordered and exhibits weak spin-orbit coupling similar to amorphous silicon (a-Si:H), many of the electronic transitions in this material take place through localized electronic states and are governed by spin-selection rules. Thus, it is possible to study these processes using electrically detected magnetic resonance spectroscopy (EDMR). Using coherent, pulsed EDMR, we observed a variety of qualitatively different spin-dependent processes. We present a mapping of the properties of these processes regarding coupling and defect type and show that the nature of many of these processes is similar to previously studied mechanisms in a-Si:H as they involve a variety of different states (dangling bonds, tails states), with various spin coupling modes (exchange, dipolar coupling). However, in contrast to a-Si:H, many of the transitions between strongly spin-coupled pairs influence the conductivity and hence they do not represent geminate recombination processes.

  2. Spin-dependent structure functions in nuclear matter and the polarized EMC effect

    SciTech Connect

    I.C. Cloet; W. Bentz; A.W. Thomas

    2005-04-01

    An excellent description of both spin-independent and spin-dependent quark distributions and structure functions has been obtained with a modified Nambu-Jona-Lasinio model, which is free of unphysical thresholds for nucleon decay into quarks--hence incorporating an important aspect of confinement. We utilize this model to investigate nuclear medium modifications to structure functions, and find that we are readily able to reproduce both nuclear matter saturation and the experimental F{sub 2N}{sup A}/F{sub 2N} ratio, that is, the EMC effect. Applying this framework to determine g{sub 1p}{sup A}, we find that the ratio g{sub 1p}{sup A}/g{sub 1p} differs significantly from 1, with the quenching caused by the nuclear medium being about twice that of the spin-independent case. This represents an exciting result, which if confirmed experimentally, will reveal much about the quark structure of nuclear matter.

  3. Spin-dependent transport across SrTiO3-based heterostructures

    NASA Astrophysics Data System (ADS)

    Swartz, Adrian

    2015-03-01

    Identification of candidate spin-preserving materials is of crucial importance for the realization of functional spin logic devices. An oxide spin channel is particularly attractive because of the ease of epitaxial integration with other functional complex oxides, which could manipulate spins in transit. Electron-doped SrTiO3 is one emerging material where high mobility conduction has been realized at the interface between LaAlO3 and SrTiO3, as well as in more traditional semiconducting Nb-doped SrTiO3 thin films. We have investigated spin injection in both systems using a three-terminal (3T) geometry with ferromagnetic electrodes and have observed magnetoresistance commonly attributed to dephasing of an ensemble spin population (Hanle effect), with associated spin lifetimes in the range of 40-130 ps, large enough for the realization of lateral spin transport devices. However, such a picture fails to explain all the experimentally observed behavior. Further experiments indicate contributions from magnetic-field modulation of spin-dependent transport through defect states in the barrier region, suggesting that the 3T approach does not uniquely probe spin accumulation in the SrTiO3 channel.

  4. High spin-dependent tunneling magnetoresistance in magnetite powders made by arc-discharge

    NASA Astrophysics Data System (ADS)

    Prakash, T.; Williams, G. V. M.; Kennedy, J.; Rubanov, S.

    2016-09-01

    We report the successful synthesis of ferrimagnetic magnetite powders made using an arc-discharge method in a partial oxygen atmosphere. X-ray and electron diffraction measurements show that the powders also contain some antiferromagnetic hematite and a small amount of FeO and Fe that has not oxidized. The Raman data show that there is a small fraction of ferrimagnetic maghemite that cannot be seen in the x-ray diffraction data. There is a wide particle size distribution where there are nanoparticles as small as 7 nm, larger faceted nanoparticles, and particles that are up to 25 μm in diameter. The saturation magnetization at high magnetic fields is ˜74% of that found in the bulk magnetite, where the lower value is due to the presence of some antiferromagnetic hematite. The temperature dependence of the saturation magnetization changes at the Verwey transition temperature, and it has a power low dependence with an exponent of 3/2 at low temperatures and 2.23 at high temperatures above the Verwey transition temperature. Electronic transport measurements were made on a cold-pressed pellet and the electrical resistance had an exponential dependence on temperature that may be due to electrostatic charging during tunneling between small nanoparticles. A large magnetoresistance from spin-dependent tunneling between the magnetite particles was observed that reached -9.5% at 120 K and 8 T.

  5. First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process

    NASA Astrophysics Data System (ADS)

    Aghasyan, M.; Akhunzyanov, R.; Alexeev, G. D.; Alexeev, M. G.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C. D. R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Büchele, M.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S.-U.; Cicuttin, A.; Crespo, M. L.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Dhara, L.; Donskov, S. V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P. D.; Faessler, M.; Ferrero, A.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; Du Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Giarra, J.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F. H.; Heitz, R.; Herrmann, F.; Horikawa, N.; D'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O. M.; Kral, Z.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Kveton, A.; Lednev, A. A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G. K.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G. V.; Meyer, M.; Meyer, W.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A. S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rogacheva, N. S.; Roskot, M.; Ryabchikov, D. I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takewaka, S.; Tasevsky, M.; Tessaro, S.; Terça, G.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vauth, A.; Veloso, J.; Virius, M.; Vit, M.; Vondra, J.; Wallner, S.; Weisrock, T.; Wilfert, M.; Ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Compass Collaboration

    2017-09-01

    The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190 GeV /c π- beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3 GeV /c2 and 8.5 GeV /c2 . Within the experimental uncertainties, the observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of quantum chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. A recent COMPASS SIDIS measurement was obtained at a hard scale comparable to that of these DY results. This opens the way for possible tests of fundamental QCD universality predictions.

  6. Equations of motion of test particles for solving the spin-dependent Boltzmann–Vlasov equation

    SciTech Connect

    Xia, Yin; Xu, Jun; Li, Bao-An; Shen, Wen-Qing

    2016-06-16

    A consistent derivation of the equations of motion (EOMs) of test particles for solving the spin-dependent Boltzmann–Vlasov equation is presented. The resulting EOMs in phase space are similar to the canonical equations in Hamiltonian dynamics, and the EOM of spin is the same as that in the Heisenburg picture of quantum mechanics. Considering further the quantum nature of spin and choosing the direction of total angular momentum in heavy-ion reactions as a reference of measuring nucleon spin, the EOMs of spin-up and spin-down nucleons are given separately. The key elements affecting the spin dynamics in heavy-ion collisions are identified. The resulting EOMs provide a solid foundation for using the test-particle approach in studying spin dynamics in heavy-ion collisions at intermediate energies. Future comparisons of model simulations with experimental data will help to constrain the poorly known in-medium nucleon spin–orbit coupling relevant for understanding properties of rare isotopes and their astrophysical impacts.

  7. Nuclear spin dependence of the reaction of H(3)+ with H2. II. Experimental measurements.

    PubMed

    Crabtree, Kyle N; Kauffman, Carrie A; Tom, Brian A; Beçka, Eftalda; McGuire, Brett A; McCall, Benjamin J

    2011-05-21

    The nuclear spin dependence of the chemical reaction H(3)(+)+ H(2) → H(2) + H(3)(+) has been studied in a hollow cathode plasma cell. Multipass infrared direct absorption spectroscopy has been employed to monitor the populations of several low-energy rotational levels of ortho- and para-H(3)(+) (o-H(3)(+) and p-H(3)(+)) in hydrogenic plasmas of varying para-H(2) (p-H(2)) enrichment. The ratio of the rates of the proton hop (k(H)) and hydrogen exchange (k(E)) reactions α ≡ k(H)/k(E) is inferred from the observed p-H(3)(+) fraction as a function of p-H(2) fraction using steady-state chemical models. Measurements have been performed both in uncooled (T(kin) ∼ 350 K) and in liquid-nitrogen-cooled (T(kin) ∼ 135 K) plasmas, marking the first time this reaction has been studied at low temperature. The value of α has been found to decrease from 1.6 ± 0.1 at 350 K to 0.5 ± 0.1 at 135 K. © 2011 American Institute of Physics.

  8. Equations of motion of test particles for solving the spin-dependent Boltzmann–Vlasov equation

    DOE PAGES

    Xia, Yin; Xu, Jun; Li, Bao-An; ...

    2016-06-16

    A consistent derivation of the equations of motion (EOMs) of test particles for solving the spin-dependent Boltzmann–Vlasov equation is presented. The resulting EOMs in phase space are similar to the canonical equations in Hamiltonian dynamics, and the EOM of spin is the same as that in the Heisenburg picture of quantum mechanics. Considering further the quantum nature of spin and choosing the direction of total angular momentum in heavy-ion reactions as a reference of measuring nucleon spin, the EOMs of spin-up and spin-down nucleons are given separately. The key elements affecting the spin dynamics in heavy-ion collisions are identified. Themore » resulting EOMs provide a solid foundation for using the test-particle approach in studying spin dynamics in heavy-ion collisions at intermediate energies. Future comparisons of model simulations with experimental data will help to constrain the poorly known in-medium nucleon spin–orbit coupling relevant for understanding properties of rare isotopes and their astrophysical impacts.« less

  9. Micromagnetic design of spin dependent tunnel junctions for optimized sensing performance

    NASA Astrophysics Data System (ADS)

    Tondra, Mark; Daughton, James M.; Nordman, Catherine; Wang, Dexin; Taylor, John

    2000-05-01

    Pinned spin dependent tunneling devices have been fabricated into high sensitivity magnetic field sensors with many favorable properties including high sensitivity (˜10 μOe/√Hz at 1 Hz and ˜100 nOe/√Hz at >10 kHz), a linear bipolar output versus applied field, high processing yields, and high temperature stability and operability (over 200 °C). However, the performance of fabricated sensors has not yet approached the theoretical limit one calculates assuming ideal behavior of the sensors' ferromagnetic layers' magnetizations. Given a total magnetoresistive signal of 30%, and typical anisotropy fields and hard axis biasing conditions, there should be a region of linear nonhysteretic response at zero field with a slope of greater than 20%/Oe. Measured responses are 1%-3%/Oe, and exhibit some hysteresis. These less than desirable effects are the result of several factors including: (1) Self-demagnetizing fields of the soft (sensing) layer; (2) stray fields from the hard (pinned) layer; (3) imperfect pinning of the hard layer; and (4) interlayer magnetic coupling across the tunnel barrier. This paper describes, in detail, the extent to which these factors affect sensor performance, and specific steps to be taken in order to minimize their deleterious influence. Specifically, the simple pinned layer is replaced by an exchange coupled synthetic antiferromagnet (CoFe/Ru/CoFe), the soft layer is made to be significantly larger in the plane than the pinned layer, and the soft layer is made as thin as possible.

  10. Analysis of Spin-dependent Peltier Effect: Spin Valves Connected in Series

    NASA Astrophysics Data System (ADS)

    Jayathilaka, Priyanga; Belyea, Dustin; Eggers, Tatiana; Kirby, Hillary; Miller, Casey

    2013-03-01

    We are reporting a systematic study of planar Nernst effect (PNE) and Spin dependent Seebeck effect (SDSE) measurements and their relation to the Anisotropic Magneto Resistance (AMR) on Py thin films grown on SiOx substrates by magnetron sputtering. A 30nm thick Py film was followed by a 15nm of Ag cross electrodes. An in-situ mask exchanging system was allowed the Py and Ag to grow without breaking the vacuum. The sample was placed on top of two thermal baths which were independently controlled by a PID controller. A constant temperature gradient of 15K/cm was applied along the sample and the resultant voltages across the Ag electrodes were measured by nanovoltmeters as the field was swept. In measuring AMR no thermal gradient was applied, and a constant current was applied using a function generator. Both PNE and SDSE showed an AMR like field dependence and angular dependence. SDSE showed a Cos2 (θ) angular dependence and PNE showed a Sin (2 θ) angular dependence. AMR showed the same angular dependence along the Py film and across the Py film respectively. This suggests both PNE and SDSE behave similar to the AMR in thin films. Supported by NSF.

  11. Spin Dependent Transport in Si/SiGe Few-Electron Quantum Dots

    NASA Astrophysics Data System (ADS)

    Simmons, Christie

    2008-03-01

    Si/SiGe quantum dots are of interest for quantum information processing due in large part to the existence of spin zero isotopes of both Si and Ge. We present the results of transport measurements and integrated charge sensing in silicon double and single quantum dots.[1,2] We observe two effects arising from spin dependent transport in a double quantum dot. First, and as expected, for one direction of current flow we observe spin blockade -- the canonical example of spin-to-charge conversion in transport. In addition, when current flow is reversed, we observe a second effect: strong tails of current extend from the sharp triangular regions in which current conventionally is observed. The presence of these tails is explained by a combination of long spin relaxation times and preferential loading of an excited spin state. We also present charge-sensing measurements of single and double quantum dots using an integrated quantum point contact. The charge sensor signal from single electron tunneling is well correlated with conventional transport through the system. When the tunnel barriers are large and transport through the dot is not measurable, charge sensing remains a viable means to track charge transitions and is used to confirm individual-electron occupation in a single quantum dot. Work performed in collaboration with Nakul Shaji, Madhu Thalakulam, Levente J. Klein, H. Luo, Hua Qin, R. H. Blick, D. E. Savage, M. G. Lagally, A. J. Rimberg, R. Joynt, M. Friesen, S. N. Coppersmith, M. A. Eriksson. Work supported by ARO, LPS, NSF and DOE. (1) Shaji, N. et al. e-print arXiv:0708.0794 (2) Simmons, C. B. et al. Appl. Phys. Lett. 91, 213103 (2007).

  12. Spin-dependent Seebeck effect in asymmetric four-terminal systems with Rashba spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Wang, Biao; Li, Mengjie; Nakayama, Tsuneyoshi; Li, Baowen

    2015-05-01

    We propose a new type of spin-dependent Seebeck effect (SDSE) emerging from the Rashba spin-orbit coupling in asymmetric four-terminal electron systems. This system generates spin currents or spin voltages along the longitudinal direction parallel to the temperature gradient in the absence of magnetic fields. The remarkable result arises from the breaking of the reflection symmetry along the transverse direction. In the meantime, the SDSE along the transverse direction, the so-called the spin Nernst effect, with spin currents or spin voltages perpendicular to the temperature gradient, can be simultaneously realized in our system. We further find that it is possible to use the temperature differences between four leads to tune the spin-dependent Seebeck coefficients.

  13. Collecting Self-Reported Data on Dating Abuse Perpetration From a Sample of Primarily Black and Hispanic, Urban-Residing, Young Adults: A Comparison of Timeline Followback Interview and Interactive Voice Response Methods.

    PubMed

    Rothman, Emily F; Heeren, Timothy; Winter, Michael; Dorfman, David; Baughman, Allyson; Stuart, Gregory

    2016-12-04

    Dating abuse is a prevalent and consequential public health problem. However, relatively few studies have compared methods of collecting self-report data on dating abuse perpetration. This study compares two data collection methods-(a) the Timeline Followback (TLFB) retrospective reporting method, which makes use of a written calendar to prompt respondents' recall, and (b) an interactive voice response (IVR) system, which is a prospective telephone-based database system that necessitates respondents calling in and entering data using their telephone keypads. We collected 84 days of data on young adult dating abuse perpetration using IVR from a total of 60 respondents. Of these respondents, 41 (68%) completed a TLFB retrospective report pertaining to the same 84-day period after that time period had ended. A greater number of more severe dating abuse perpetration events were reported via the IVR system. Participants who reported any dating abuse perpetration were more likely to report more frequent abuse perpetration via the IVR than the TLFB (i.e., may have minimized the number of times they perpetrated dating abuse on the TLFB). The TLFB method did not result in a tapering off of reported events past the first week as it has in prior studies, but the IVR method did result in a tapering off of reported events after approximately the sixth week. We conclude that using an IVR system for self-reports of dating abuse perpetration may not have substantial advantages over using a TLFB method, but researchers' choice of mode may vary by research question, resources, sample, and setting. © The Author(s) 2016.

  14. Electronic spin polarization and the spin-dependent bandstructure in GaAs probed by optically pumped NMR

    SciTech Connect

    Crooker, Scott A; Ramaswamy, Kannan; Mui, Stacy; Hayes, Sophia E; Pan, Xingyuan; Sanders, Gary D; Stanton, Christopher J

    2008-01-01

    High resolution optically pumped NMR (OPNMR) experiments are used to resolve fine features in the spin-dependent electronic structure of the valence bands in semi-insulating GaAs. By theoretically calculating oscillations in the OPNMR signal intensity with respect to the excitation energy, we have mapped out the conduction band electronic spin polarization under optical pumping. Comparison with a theoretical analysis of the oscillatory experimental features allows the extraction of semiconductor energy band parameters.

  15. Spectroscopic and Theoretical Study of Spin-Dependent Electron Transfer in an Iron(III) Superoxo Complex.

    PubMed

    Stout, Heather D; Kleespies, Scott T; Chiang, Chien-Wei; Lee, Way-Zen; Que, Lawrence; Münck, Eckard; Bominaar, Emile L

    2016-06-06

    It was shown previously (J. Am. Chem. Soc. 2014, 136, 10846) that bubbling of O2 into a solution of Fe(II)(BDPP) (H2BDPP = 2,6-bis[[(S)-2-(diphenylhydroxymethyl)-1-pyrrolidinyl]methyl]pyridine) in tetrahydrofuran at -80 °C generates a high-spin (SFe = (5)/2) iron(III) superoxo adduct, 1. Mössbauer studies revealed that 1 is an exchange-coupled system, [Formula: see text], where SR = (1)/2 is the spin of the superoxo radical, of which the spectra were not well enough resolved to determine whether the coupling was ferromagnetic (S = 3 ground state) or antiferromagnetic (S = 2). The glass-forming 2-methyltetrahydrofuran solvent yields highly resolved Mössbauer spectra from which the following data have been extracted: (i) the ground state of 1 has S = 3 (J < 0); (ii) |J| > 15 cm(-1); (iii) the zero-field-splitting parameters are D = -1.1 cm(-1) and E/D = 0.02; (iv) the major component of the electric-field-gradient tensor is tilted ≈7° relative to the easy axis of magnetization determined by the MS = ±3 and ±2 doublets. The excited-state MS = ±2 doublet yields a narrow parallel-mode electron paramagnetic resonance signal at g = 8.03, which was used to probe the magnetic hyperfine splitting of (17)O-enriched O2. A theoretical model that considers spin-dependent electron transfer for the cases where the doubly occupied π* orbital of the superoxo ligand is either "in" or "out" of the plane defined by the bent Fe-OO moiety correctly predicts that 1 has an S = 3 ground state, in contrast to the density functional theory calculations for 1, which give a ground state with both the wrong spin and orbital configuration. This failure has been traced to a basis set superposition error in the interactions between the superoxo moiety and the adjacent five-membered rings of the BDPP ligand and signals a fundamental problem in the quantum chemistry of O2 activation.

  16. Role of interface transparency and spin-dependent scattering in diffusive ferromagnet/superconductor heterostructures

    NASA Astrophysics Data System (ADS)

    Linder, Jacob; Yokoyama, Takehito; Sudbø, Asle

    2008-05-01

    We present a numerical study of the density of states in a ferromagnet/superconductor junction and the Josephson current in a superconductor/ferromagnet/superconductor junction in the diffusive limit by solving the Usadel equation with Nazarov’s boundary conditions. Our calculations are valid for an arbitrary interface transparency and an arbitrary spin-dependent scattering rate, which allows us to explore the entire proximity-effect regime. We first investigate how the proximity-induced anomalous Green’s function affects the density of states in the ferromagnet for three magnitudes of the exchange field h compared to the superconducting gap Δ : (i) h≲Δ , (ii) h≳Δ , and (iii) h≫Δ . In each case, we consider the effect of the barrier transparency and allow for various concentrations of magnetic impurities. We clarify features that may be expected in the various parameter regimes accessible for the ferromagnetic film, with regard to thickness and exchange field. In particular, we address how the zero-energy peak and minigap observed in experiments may be understood in terms of the interplay between the singlet and the triplet anomalous Green’s functions and their dependence on the concentration of magnetic impurities. Our results should serve as a useful tool for the quantitative analysis of experimental data. We also investigate the role of the barrier transparency and spin-flip scattering in a superconductor/ferromagnet/superconductor junction. We suggest that such diffusive Josephson junctions with large residual values of the supercurrent at the 0-π transition, where the first harmonic term in the current vanishes, may be used as efficient supercurrent-switching devices. We numerically solve for the Josephson current in such a junction to clarify to what extent this idea may be realized in an experimental setup. It is also found that uniaxial spin-flip scattering has a very different effect on the 0-π transition points depending on whether one

  17. Precision Measurement of the Spin-dependent Asymmetry in the Threshold Region of Quasielastic 3He

    SciTech Connect

    Xiong, Feng

    2002-09-01

    The first precision measurement of the spin-dependent asymmetry in the threshold region of polarized 3He(polarized e, e') was carried out in Hall A at the Jefferson Laboratory, using a longitudinally polarized continuous electron beam incident on a high-pressure polarized 3He gas target. The polarized electron beam was generated by illuminating a strained GaAs cathode with high intensity circularly polarized laser light, and an average beam polarization of about 70% was achieved. The 3He target was polarized based on the principle of spin-exchange optical pumpint and the average target polarization was about 30%. The scattered electrons were detected in the two Hall A high resolution spectrometers, HRSe and HRSh. The data from HRSh were used for this analysis and covered both the elastic peak and the threshold region. Two kinematic points were measured in the threshold region, one with a central Q2-value of 0.1 (GeV/c)2 at an incident beam energy E0 = 0.778 GeV and the other with a central Q2-value of 0.2 (GeV/c)2 at E-0 = 1.727 GeV. The average beam current was 10 mu-A, which was mainly due to the limitation of the polarized 3He target. The measured asymmetry was compared with both plane wave impulse approximation (PWIA) calculations and non-relativistic full Faddeev calculations which include both final-state interactions (FSIs) and meson-exchange currents (MECs) effects. The poor description of the data by PWIA calculations at both Q2-values suggests the existence of strong FSI and MEC effects in the threshold region of polarized 3He (polarized e, e'). Indeed, the agreement between the data and full calculations is very good at Q2 = 0.1 (GeV/c)2. On the other hand, a small discrepancy at Q2 = 0.2 (GeV/c)2 is observed, which might be due to some Q2 -dependent effects such as relativity and

  18. Electrically detected magnetic resonance of phosphorous due to spin dependent recombination with triplet centers in γ-irradiated silicon

    NASA Astrophysics Data System (ADS)

    Akhtar, W.; Morishita, H.; Vlasenko, L. S.; Poloskin, D. S.; Itoh, K. M.

    2009-12-01

    Electrically detected magnetic resonance (EDMR) of phosphorus in silicon was detected in weak magnetic fields at low resonance frequencies of 200-400 MHz before and after irradiation of samples by γ-rays. EDMR spectra were detected by measuring dc-photoconductivity of samples under band-gap illumination. Phosphorus (P0) EDMR lines are accompanied always with the single line (S-line) with g-factor ≈2.01 originated most likely from the surface recombination centers. Strong, about 10 times, increase of the P0 and S signals was found in the same samples after irradiation with the doses of (3-6)×1015 γ/cm-2. For these doses of irradiation we were also able to see the ESR transition between entangled states of phosphorous formed at low magnetic field. This shows the higher efficiency of spin dependent recombination (SDR) process in irradiated samples. In addition, several new EDMR lines emerged after irradiation. Some of them arose from the spin dependent recombination through the photoexcited triplet states of A-centers (oxygen+vacancy complex).

  19. An Exact Separation of the Spin-Free and Spin-Dependent Terms of the Dirac-Coulomb-Breit Hamiltonian

    NASA Technical Reports Server (NTRS)

    Dyall, Kenneth G.

    1994-01-01

    The Dirac Hamiltonian is transformed by extracting the operator (sigma x p)/2mc from the small component of the wave function and applying it to the operators of the original Hamiltonian. The resultant operators contain products of Paull matrices that can be rearranged to give spin-free and spin-dependent operators. These operators are the ones encountered in the Breit-Pauli Hamiltonian, as well as some of higher order in alpha(sup 2). However, since the transformation of the original Dirac Hamiltonian is exact, the new Hamiltonian can be used in variational calculations, with or without the spin-dependent terms. The new small component functions have the same symmetry properties as the large component. Use of only the spin-free terms of the new Hamiltonian permits the same factorization over spin variables as in nonrelativistic theory, and therefore all the post-Self-Consistent Field (SCF) machinery of nonrelativistic calculations can be applied. However, the single-particle functions are two-component orbitals having a large and small component, and the SCF methods must be modified accordingly. Numerical examples are presented, and comparisons are made with the spin-free second-order Douglas-Kroll transformed Hamiltonian of Hess.

  20. Spin-incoherent Luttinger liquid of one-dimensional spin-1 Tonks-Girardeau Bose gases: Spin-dependent properties

    NASA Astrophysics Data System (ADS)

    Jen, H. H.; Yip, S.-K.

    2017-05-01

    Spin-incoherent Luttinger liquid (SILL) is a different universal class from the Luttinger liquid. This difference results from the spin incoherence of the system when the thermal energy of the system is higher than the spin excitation energy. We consider one-dimensional spin-1 Bose gas in the SILL regime and investigate its spin-dependent many-body properties. In Tonks-Girardeau limit, we are able to write down the general wave functions in a harmonic trap. We numerically calculate the spin-dependent (spin-plus, minus, and zero) momentum distributions in the sector of zero magnetization which allows us to demonstrate the most significant spin-incoherent feature compared to the spinless or spin-polarized case. In contrast to the spinless Bose gas, the momentum distributions are broadened and in the large momentum limit follow the same asymptotic 1 /p4 dependence but with reduced coefficients. While the density matrices and momentum distributions differ between different spin components for small N , at large N they approach each other. We show these by analytic arguments and numerical calculations up to N =16 .

  1. Effect of amino on spin-dependent transport through a junction of fused oligothiophenes between graphene electrodes

    NASA Astrophysics Data System (ADS)

    Cao, Liemao; Li, Xiaobo; Liu, Guang; Liu, Ziran; Zhou, Guanghui

    2017-05-01

    The influence of chemical side groups is significant in physical or chemical understanding the transport through the single molecular junction. Motivated by the recent successful fabrication and measurement of a single organic molecule sandwiched between graphene electrodes (Prins et al., 2011), here we study the spin-dependent transport properties through a junction of a fused oligothiophenes molecule embedded between two zigzag-edged graphene nanoribbon (ZGNR) electrodes. The molecule with and without an attached amino NH2 side group is considered, respectively, and external magnetic fields or FM stripes are applied onto the ZGNRs to initially orient the magnetic alignment of the electrodes for the spin-dependent consideration. By the ab initio calculations based on the density functional theory combined with nonequilibrium Green's function formalism, we have demonstrated the remarkable difference in the spin-charge transport property between the junctions of the molecule with and without NH2 side group. In particular, the junction with side group shows more obvious NDR. In addition, it exhibits an interesting dual spin-filtering effect when the magnetic alignment in electrodes is initially antiparallel-oriented. The mechanisms of the results are revealed and discussed in terms of the spin-resolved transmission spectrum associated with the frontier molecular orbitals evolution, the molecular projected self-consistent Hamiltonian eigenvalues, and the local density of states.

  2. Spin-orbit coupling and surface magnetism coexisting in spin-dependent low-energy He+-ion surface scattering

    NASA Astrophysics Data System (ADS)

    Suzuki, T. T.; Sakai, O.

    2017-04-01

    Surface magnetism is analyzed by spin-dependent He+-ion neutralization (the Auger neutralization) in the vicinity of a surface using an electron spin-polarized low-energy He+-ion beam [spin-polarized ion scattering spectroscopy (SP-ISS)]. Recently, spin-orbit coupling (SOC) has been found to act as another mechanism of spin-dependent low-energy He+-ion scattering. Thus, it is crucial for surface magnetism analyses by SP-ISS to separate those two mechanisms. In the present study, we investigated the spin-induced asymmetry in scattering of low-energy He+ ions on ultrathin Au and Sn films as well as the oxygen adsorbate on a magnetized-Fe(100) surface where these two mechanisms may coexist. We found that the Fe surface magnetism immediately disappeared with the growth of those overlayers. On the other hand, we observed no induced spin polarization in the Au and Sn thin films even in the very initial stage of the growth. We also observed that the spin asymmetry of the O adsorbate was induced by the magnetism of the underlying Fe substrate. The present study demonstrates that the two mechanisms of the spin-asymmetric He+-ion scattering (the ion neutralization and SOC) can be separated by an azimuthal-angle-resolved SP-ISS measurement.

  3. An Exact Separation of the Spin-Free and Spin-Dependent Terms of the Dirac-Coulomb-Breit Hamiltonian

    NASA Technical Reports Server (NTRS)

    Dyall, Kenneth G.

    1994-01-01

    The Dirac Hamiltonian is transformed by extracting the operator (sigma x p)/2mc from the small component of the wave function and applying it to the operators of the original Hamiltonian. The resultant operators contain products of Paull matrices that can be rearranged to give spin-free and spin-dependent operators. These operators are the ones encountered in the Breit-Pauli Hamiltonian, as well as some of higher order in alpha(sup 2). However, since the transformation of the original Dirac Hamiltonian is exact, the new Hamiltonian can be used in variational calculations, with or without the spin-dependent terms. The new small component functions have the same symmetry properties as the large component. Use of only the spin-free terms of the new Hamiltonian permits the same factorization over spin variables as in nonrelativistic theory, and therefore all the post-Self-Consistent Field (SCF) machinery of nonrelativistic calculations can be applied. However, the single-particle functions are two-component orbitals having a large and small component, and the SCF methods must be modified accordingly. Numerical examples are presented, and comparisons are made with the spin-free second-order Douglas-Kroll transformed Hamiltonian of Hess.

  4. Spin-dependent Seebeck Effect, Thermal Colossal Magnetoresistance and Negative Differential Thermoelectric Resistance in Zigzag Silicene Nanoribbon Heterojunciton

    PubMed Central

    Fu, Hua-Hua; Wu, Dan-Dan; Zhang, Zu-Quan; Gu, Lei

    2015-01-01

    Spin-dependent Seebeck effect (SDSE) is one of hot topics in spin caloritronics, which examine the relationships between spin and heat transport in materials. Meanwhile, it is still a huge challenge to obtain thermally induced spin current nearly without thermal electron current. Here, we construct a hydrogen-terminated zigzag silicene nanoribbon heterojunction, and find that by applying a temperature difference between the source and the drain, spin-up and spin-down currents are generated and flow in opposite directions with nearly equal magnitudes, indicating that the thermal spin current dominates the carrier transport while the thermal electron current is much suppressed. By modulating the temperature, a pure thermal spin current can be achieved. Moreover, a thermoelectric rectifier and a negative differential thermoelectric resistance can be obtained in the thermal electron current. Through the analysis of the spin-dependent transport characteristics, a phase diagram containing various spin caloritronic phenomena is provided. In addition, a thermal magnetoresistance, which can reach infinity, is also obtained. Our results put forward an effective route to obtain a spin caloritronic material which can be applied in future low-power-consumption technology. PMID:26000658

  5. Spin-dependent energy bands and spin polarization in two-dimensional spin-orbit lateral superlattices.

    PubMed

    Zhang, R L; Qi, D X; Wang, D L; Li, J; Peng, R W; Huang, R S; Wang, Mu

    2013-02-01

    In this work, we theoretically investigate the spin-split energy bands of electrons and spin-polarized transport in two-dimensional (2D) spin-orbit lateral superlattices (SOLSLs), where the square rods with Rashba spin-orbit coupling (SOC) are distributed periodically by applying gate voltages on the semiconductor. Within the Landauer framework of ballistic transport, the energy bands, the electrical conductance, the spin polarization and the spin-dependent electronic charge distributions have been calculated. It is found that the energy minibands are formed and the energy levels are split up by the Rashba SOC. As a result, the spin-polarized conductance is obtained even in the absence of external magnetic fields and magnetic materials. Meanwhile, the spin polarization can approach high values in the SOLSLs by manipulating the strength of SOC. Furthermore, the spin-dependent electronic charge distributions have been obtained, which present a clear picture of spin-polarized conductance. Our investigations have the potential applications in spin-based quantum devices and semiconductor spintronics.

  6. Spin-dependent Seebeck Effect, Thermal Colossal Magnetoresistance and Negative Differential Thermoelectric Resistance in Zigzag Silicene Nanoribbon Heterojunciton

    NASA Astrophysics Data System (ADS)

    Fu, Hua-Hua; Wu, Dan-Dan; Zhang, Zu-Quan; Gu, Lei

    2015-05-01

    Spin-dependent Seebeck effect (SDSE) is one of hot topics in spin caloritronics, which examine the relationships between spin and heat transport in materials. Meanwhile, it is still a huge challenge to obtain thermally induced spin current nearly without thermal electron current. Here, we construct a hydrogen-terminated zigzag silicene nanoribbon heterojunction, and find that by applying a temperature difference between the source and the drain, spin-up and spin-down currents are generated and flow in opposite directions with nearly equal magnitudes, indicating that the thermal spin current dominates the carrier transport while the thermal electron current is much suppressed. By modulating the temperature, a pure thermal spin current can be achieved. Moreover, a thermoelectric rectifier and a negative differential thermoelectric resistance can be obtained in the thermal electron current. Through the analysis of the spin-dependent transport characteristics, a phase diagram containing various spin caloritronic phenomena is provided. In addition, a thermal magnetoresistance, which can reach infinity, is also obtained. Our results put forward an effective route to obtain a spin caloritronic material which can be applied in future low-power-consumption technology.

  7. Spin-dependent Seebeck Effect, Thermal Colossal Magnetoresistance and Negative Differential Thermoelectric Resistance in Zigzag Silicene Nanoribbon Heterojunciton.

    PubMed

    Fu, Hua-Hua; Wu, Dan-Dan; Zhang, Zu-Quan; Gu, Lei

    2015-05-22

    Spin-dependent Seebeck effect (SDSE) is one of hot topics in spin caloritronics, which examine the relationships between spin and heat transport in materials. Meanwhile, it is still a huge challenge to obtain thermally induced spin current nearly without thermal electron current. Here, we construct a hydrogen-terminated zigzag silicene nanoribbon heterojunction, and find that by applying a temperature difference between the source and the drain, spin-up and spin-down currents are generated and flow in opposite directions with nearly equal magnitudes, indicating that the thermal spin current dominates the carrier transport while the thermal electron current is much suppressed. By modulating the temperature, a pure thermal spin current can be achieved. Moreover, a thermoelectric rectifier and a negative differential thermoelectric resistance can be obtained in the thermal electron current. Through the analysis of the spin-dependent transport characteristics, a phase diagram containing various spin caloritronic phenomena is provided. In addition, a thermal magnetoresistance, which can reach infinity, is also obtained. Our results put forward an effective route to obtain a spin caloritronic material which can be applied in future low-power-consumption technology.

  8. Effect of oxide barrier height in spin dependent tunneling in MTJ of FeO-MgO multilayer structure

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, M.; Nemade, H.; Bandyopadhyay, D.

    2016-10-01

    We study the spin dependent tunneling current properties through oxide multilayers in a magnetic tunnel junction (MTJ). For this purpose, nonequilibrium Green's function approach along-with the density-functional theory have been applied. We employed three structural models of FeO-MgO-FeO multi-layer with three different width of FeO and MgO layer. An atomistic model is considered to describe the effect of oxide multilayers of different heights. Spin dependent study for tunneling reveals that the parallel spin shows higher tunneling current whereas anti-parallel spin conducts very less. Further, the lowest tunneling current is obtained for the case where the FeO and MgO each has 3 atomic layers of height whereas the tunneling current is highest in 4 atomic layers of FeO/1 atomic layers of MgO/4 atomic layers of MgO multilayer structure. Importantly, when the MgO or FeO layers are increased or decreased from this level, the tunneling current decreases significantly. The study reveals that the layer height in the tunneling domain can be important factor for tuning and adjusting tunneling current in the nanoscale regime of oxide layer thickness.

  9. Spin-dependent transport behavior in C60 and Alq3 based spin valves with a magnetite electrode (invited)

    NASA Astrophysics Data System (ADS)

    Zhang, Xianmin; Mizukami, Shigemi; Ma, Qinli; Kubota, Takahide; Oogane, Mikihiko; Naganuma, Hiroshi; Ando, Yasuo; Miyazaki, Terunobu

    2014-05-01

    The spin-dependent transport behavior in organic semiconductors (OSs) is generally observed at low temperatures, which likely results from poor spin injection efficiency at room temperature from the ferromagnetic metal electrodes to the OS layer. Possible reasons for this are the low Curie temperature and/or the small spin polarization efficiency for the ferromagnetic electrodes used in these devices. Magnetite has potential as an advanced candidate for use as the electrode in spintronic devices, because it can achieve 100% spin polarization efficiency in theory, and has a high Curie temperature (850 K). Here, we fabricated two types of organic spin valves using magnetite as a high efficiency electrode. C60 and 8-hydroxyquinoline aluminum (Alq3) were employed as the OS layers. Magnetoresistance ratios of around 8% and over 6% were obtained in C60 and Alq3-based spin valves at room temperature, respectively, which are two of the highest magnetoresistance ratios in organic spin valves reported thus far. The magnetoresistance effect was systemically investigated by varying the thickness of the Alq3 layer. Moreover, the temperature dependence of the magnetoresistance ratios for C60 and Alq3-based spin valves were evaluated to gain insight into the spin-dependent transport behavior. This study provides a useful method in designing organic spin devices operated at room temperature.

  10. Spin-dependent scattering from gated potential obstacles in graphene systems

    NASA Astrophysics Data System (ADS)

    Asmar, Mahmoud; Ulloa, Sergio

    2011-03-01

    We study the scattering of Dirac fermions in a sheet of graphene from potential obstacles created by external gates in the presence of both intrinsic and extrinsic Spin-Orbit(SO) interactions. Obtaining an analytical solution in real-space representation for the eigenvectors allows us to calculate the phase shifts generated by a finite-size obstacle in the presence of SO interactions. These states take into account the total angular momentum of the Hamiltonian, which includes spin, pseudo-spin and orbital angular momentum. We find an interesting interplay of both SO interactions, which results in oscillations of the spin-flip cross sections with energy; this also generates a difference between both cross sections for different interaction ranges. These results may open a possibility of obtaining spin-polarized currents that are of importance in the field of spintronics. Supported by NSF PIRE and MWN/CIAM.

  11. SDS designed primarily for discrete applications

    SciTech Connect

    Postma, S.

    1996-11-01

    Control system designers face a wide range of issues when integrating various networked devices and control functions into a cohesive system. These include partitioning the control solution into manageable subtasks; defining required system resources; system performance; fault tolerance; fault recovery; and interactions with cell and supervisory networks. Control network selection is further complicated by the wide range of available choices. Fieldbus Foundation network and device networks are generally characterized as being quite different, with nonoverlapping functions. Upon closer scrutiny, however, the application domains of each clearly overlap. Often the same device works on either type of network. Foundation fieldbus is optimized for continuous process control application that require data collection from process instruments and controllers. Device-level networks are optimized for discrete logic control in applications typically found in material handling and machine control. The Smart Distributed System (SDS) protocol is designed to meet the speed, reliability, and flexibility required for manufacturing automation applications. The speed requirements for real-time control are easily met. SDS achieves high reliability through error detection and correction as well as an application layer acknowledgment. The flexibility is derived from the wide range of devices that can function on a network. SDS protocol uses three of the seven layers defined in the ISO open systems interconnection (OSI) reference model. As is typical of control networks, features of the middle layers are combined with the data-link and application layers to minimize resources and overhead costs of additional hardware and software. 5 figs.

  12. Solid state magnetic field sensors for micro unattended ground networks using spin dependent tunneling

    NASA Astrophysics Data System (ADS)

    Tondra, Mark; Nordman, Catherine A.; Lange, Erik H.; Reed, Daniel; Jander, Albrect; Akou, Seraphin; Daughton, James

    2001-09-01

    Micro Unattended Ground Sensor Networks will likely employ magnetic sensors, primarily for discrimination of objects as opposed to initial detection. These magnetic sensors, then, must fit within very small cost, size, and power budgets to be compatible with the envisioned sensor suites. Also, a high degree of sensitivity is required to minimize the number of sensor cells required to survey a given area in the field. Solid state magnetoresistive sensors, with their low cost, small size, and ease of integration, are excellent candidates for these applications assuming that their power and sensitivity performance are acceptable. SDT devices have been fabricated into prototype magnetic field sensors suitable for use in micro unattended ground sensor networks. They are housed in tiny SOIC 8-pin packages and mounted on a circuit board with required voltage regulation, signal amplification and conditioning, and sensor control and communications functions. The best sensitivity results to date are 289 pT/rt. Hz at 1 Hz, and and 7 pT/rt. Hz at f > 10 kHz. Expected near term improvements in performance would bring these levels to approximately 10 pT/rt Hz at 1 Hz and approximately 1 pT/rt. Hz at > 1 kHz.

  13. Dramatic impact of the giant local magnetic fields on spin-dependent recombination processes in gadolinium based garnets

    SciTech Connect

    Romanov, N. G. Tolmachev, D. O.; Gurin, A. S.; Uspenskaya, Yu. A.; Asatryan, H. R.; Badalyan, A. G.; Baranov, P. G.; Wieczorek, H.; Ronda, C.

    2015-06-29

    A giant magnetic field effect on spin-dependent recombination of the radiation-induced defects has been found in cerium doped gadolinium based garnet crystals and ceramics, promising materials for scintillator applications. A sharp and strong increase in the afterglow intensity stimulated by external magnetic field and an evidence of the magnetic field memory have been discovered. The effect was ascribed to huge Gd-induced internal magnetic fields, which suppress the recombination, and cross-relaxation with Gd{sup 3+} ions leading to reorientation of the spins of the electron and hole centers. Thus, the spin system of radiation-induced defects in gadolinium garnet based scintillator materials was shown to accumulate significant energy which can be released in external magnetic fields.

  14. A spin dependent recombination study of radiation induced defects at and near the Si/SiO sub 2 interface

    SciTech Connect

    Jupina, M.A.; Lenahan, P.M. )

    1989-12-01

    A new electron spin resonance technique, spin dependent recombination (SDR) permits extremely rapid, high signal to noise ratio electron spin resonance (ESR) measurements of electrically active radiation damage centers in (relatively) hard MOS transistors in integrated circuits. Using SDR the authors observe the radiation induced buildup of Pbo and E' centers at relatively low concentration in individual MOSFETs in integrated circuits with (100) silicon surface orientation. Earlier ESR studies of extremely large ({approximately}1 cm{sup 2}) capacitor structures have identified Pb and E' centers as the dominant radiation induced defects in MOS devices. The authors discuss how their results extend and confirm these earlier results and at least qualitatively answer objections to the earlier work related to the relevance of large capacitor studies to transistors in an integrated circuit.

  15. Spin-dependent beating patterns in thermoelectric properties: Filtering the carriers of the heat flux in a Kondo adatom system

    NASA Astrophysics Data System (ADS)

    Seridonio, A. C.; Siqueira, E. C.; Franco, R.; Silva-Valencia, J.; Shelykh, I. A.; Figueira, M. S.

    2014-11-01

    We theoretically investigate the thermoelectric properties of a spin-polarized two-dimensional electron gas hosting a Kondo adatom hybridized with a STM tip. Such a setup is treated within the single-impurity Anderson model in combination with the atomic approach for the Green's functions. Due to the spin dependence of the Fermi wave numbers, the electrical and thermal conductances together with thermopower and Lorenz number reveal beating patterns as a function of the STM tip position in the Kondo regime. In particular, by tuning the lateral displacement of the tip with respect to the adatom vicinity, the temperature, and the position of the adatom level, one can change the sign of the Seebeck coefficient through charge and spin. This opens a possibility of the microscopic control of the heat flux analogously to that established for the electrical current.

  16. Thermal spin-transfer torque driven by the spin-dependent Seebeck effect in metallic spin-valves

    NASA Astrophysics Data System (ADS)

    Choi, Gyung-Min; Moon, Chul-Hyun; Min, Byoung-Chul; Lee, Kyung-Jin; Cahill, David G.

    2015-07-01

    The coupling of spin and heat gives rise to new physical phenomena in nanoscale spin devices. In particular, spin-transfer torque (STT) driven by thermal transport provides a new way to manipulate local magnetization. We quantify thermal STT in metallic spin-valve structures using an intense and ultrafast heat current created by picosecond pulses of laser light. Our result shows that thermal STT consists of demagnetization-driven and spin-dependent Seebeck effect (SDSE)-driven components; the SDSE-driven STT becomes dominant after 3 ps. The sign and magnitude of the SDSE-driven STT can be controlled by the composition of a ferromagnetic layer and the thickness of a heat sink layer.

  17. Measurement of the deep-inelastic spin-dependent structure functions of the proton and neutron at HERA

    SciTech Connect

    Beck, D.H.; Filippone, B.W.; Jourdan, J.; McKeown, R.D.; Milner, R.G.; Woodward, C.E.; Freedman, S.J.; Geesaman, D.F.; Holt, R.J.; Jackson, H.E.

    1988-01-01

    It is possible to measure the deep-inelastic spin-dependent structure functions g/sub 1//sup p/(x) and g/sub 1//sup n/(x) for the proton and neutron using internal polarized hydrogen, deuterium, and /sup 3/He targets of polarization 50% and thickness 10/sup 14/ to 10/sup 15/ cm/sup -2/ and the 60 mA longitudinally polarized 30 GeV electron beam in the HERA electron storage ring. The measurement of the deep-inelastic spin-structure of both isospin states of the nucleon at the same kinematics and using the same apparatus allows the Bjorken sum rule to be experimentally checked. In addition, it uniquely constrains the spin distribution of the u and d quarks as a function of x in any model of the nucleon. Possible target and detector configurations are described and an estimate of the accuracy of such a measurement is presented.

  18. Unidirectional Spin-Dependent Molecule-Ferromagnet Hybridized States Anisotropy in Cobalt Phthalocyanine Based Magnetic Tunnel Junctions.

    PubMed

    Barraud, Clément; Bouzehouane, Karim; Deranlot, Cyrile; Fusil, Stéphane; Jabbar, Hashim; Arabski, Jacek; Rakshit, Rajib; Kim, Dong-Jik; Kieber, Christophe; Boukari, Samy; Bowen, Martin; Beaurepaire, Eric; Seneor, Pierre; Mattana, Richard; Petroff, Frédéric

    2015-05-22

    Organic or molecular spintronics is a rising field of research at the frontier between condensed matter physics and chemistry. It aims to mix spin physics and the richness of chemistry towards designing new properties for spin electronics devices through engineering at the molecular scale. Beyond the expectation of a long spin lifetime, molecules can be also used to tailor the spin polarization of the injected current through the spin-dependent hybridization between molecules and ferromagnetic electrodes. In this Letter, we provide direct evidence of a hybrid interface spin polarization reversal due to the differing hybridization between phthalocyanine molecules and each cobalt electrode in Co/CoPc/Co magnetic tunnel junctions. Tunnel magnetoresistance and anisotropic tunnel magnetoresistance experiments show that interfacial hybridized electronic states have a unidirectional anisotropy that can be controlled by an electric field and that spin hybridization at the bottom and top interfaces differ, leading to an inverse tunnel magnetoresistance.

  19. Spin-dependent ballistic electron transport through Fe/MgO/Fe from ab-initio Green function embedding

    NASA Astrophysics Data System (ADS)

    Wortmann, Daniel; Blugel, Stefan; Ishida, Hiroshi

    2003-03-01

    An investigation of the Fe/MgO/Fe junction as a model system for tunnel-magneto-resistance (TMR) devices will be presented. We focus on the role of the electronic and geometric interface structure on the spin-dependent conductance by taking the interlayer relaxation at the Fe/MgO interface and the effect of a formation of interface FeO into account. We apply a recently developed efficient method for calculating the conductance of ballistic electrons through an interface from first-principles using the embedding approach of Inglesfield. In our method the Landauer-Büttiker formula for ballistic transport is expressed in terms of quantities that are available in the embedded Green-function calculations. The embedding approach is implemented within the full-potential linearized augmented plane method as realized in the FLEUR code.

  20. Sum rule measurements of the spin-dependent compton amplitude (nucleon spin structure at Q{sup 2} = 0)

    SciTech Connect

    Babusci, D.; Giordano, G.; Baghaei, H.; Cichocki, A.; Blecher, M.; Breuer, M.; Commeaux, C.; Didelez, J.P.; Caracappa, A.; Fan, Q.

    1995-12-31

    Energy weighted integrals of the difference in helicity-dependent photo-production cross sections ({sigma}{sub {1/2}} - {sigma}{sub 3/2}) provide information on the nucleon`s Spin-dependent Polarizability ({gamma}), and on the spin-dependent part of the asymptotic forward Compton amplitude through the Drell-Hearn-Gerasimov (DHG) sum rule. (The latter forms the Q{sup 2}=0 limit of recent spin-asymmetry experiments in deep-inelastic lepton-scattering.) There are no direct measurements of {sigma}{sub {1/2}} or {sigma}{sub 3/2}, for either the proton or the neutron. Estimates from current {pi}-photo-production multipole analyses, particularly for the proton-neutron difference, are in good agreement with relativistic-l-loop Chiral calculations ({chi}PT) for {gamma} but predict large deviations from the DHG sum rule. Either (a) both the 2-loop corrections to the Spin-Polarizability are large and the existing multipoles are wrong, or (b) modifications to the Drell-Hearn-Gerasimov sum rule are required to fully describe the isospin structure of the nucleon. The helicity-dependent photo-reaction amplitudes, for both the proton and the neutron, will be measured at LEGS from pion-threshold to 470 MeV. In these double-polarization experiments, circularly polarized photons from LEGS will be used with SPHICE, a new frozen-spin target consisting of {rvec H} {center_dot} {rvec D} in the solid phase. Reaction channels will be identified in SASY, a large detector array covering about 80% of 4{pi}. A high degree of symmetry in both target and detector will be used to minimize systematic uncertainties.

  1. CoFe alloy as middle layer for strong spin dependent quantum well resonant tunneling in double barrier magnetic tunnel junctions

    SciTech Connect

    Liu, R. S.; Yang, See-Hun; Jiang, Xin; Zhang, Xiaoguang; Rice, Philip M.; Canali, Carlo M.; Parkin, S. S. P.

    2013-01-01

    We report the spin-dependent quantum well resonant tunneling effect in CoFe/MgO/CoFe/MgO/CoFeB (CoFe) double barrier magnetic tunnel junctions. The dI/dV spectra reveal clear resonant peaks for the parallel magnetization configurations, which can be matched to quantum well resonances obtained from calculation. The differential TMR exhibits an oscillatory behavior with a sign change due to the formation of the spin-dependent QW states in the middle CoFe layer. Also, we observe pronounced TMR enhancement at resonant voltages at room temperature, suggesting that it is very promising to achieve high TMR using the spin-dependent QW resonant tunneling effect.

  2. Generalized Holstein model for spin-dependent electron-transfer reactions

    NASA Astrophysics Data System (ADS)

    Yang, Li-Ping; Ai, Qing; Sun, C. P.

    2012-03-01

    Some chemical reactions are described by electron transfer (ET) processes. The underlying mechanism could be modeled as a polaron motion in the molecular crystal—the Holstein model. By taking spin degrees of freedom into consideration, we generalize the Holstein model (molecular crystal model) to microscopically describe an ET chemical reaction. In our model, the electron spins in the radical pair simultaneously interact with a magnetic field and their nuclear-spin environments. By virtue of the perturbation approach, we obtain the chemical reaction rates for different initial states. It is discovered that the chemical reaction rate of the triplet state demonstrates its dependence on the direction of the magnetic field while the counterpart of the singlet state does not. This difference is attributed to the explicit dependence of the triplet state on the direction when the axis is rotated. Our model may provide a possible candidate for the microscopic origin of the avian compass.

  3. Spin-dependent thermoelectric phenomena in a quantum dot attached to ferromagnetic and superconducting electrodes

    NASA Astrophysics Data System (ADS)

    Trocha, Piotr; Barnaś, Józef

    2017-04-01

    We investigate transport and thermoelectric properties of hybrid systems based on a single-level quantum dot and one superconducting lead. The other lead is generally normal-metallic ferromagnet. In the latter case, single-particle transport is spin polarized. Our main interest is in the interplay of Andreev tunneling of Cooper pairs and single-particle tunneling. The latter is responsible for relatively large thermopower and figure of merit due to a diverging density of single-particle states at the superconducting gap edges. A system with ferromagnetic and superconducting leads can also reveal spin thermoelectric phenomena. A finite superconducting gap is considered within the BCS theory, and the thermoelectric coefficients are calculated by means of nonequilibrium Green's function technique within Hartree-Fock-type approximation with respect to the intradot Coulomb interaction.

  4. Inelastic dark matter with spin-dependent couplings to protons and large modulation fractions in DAMA

    SciTech Connect

    Scopel, Stefano; Yoon, Kook-Hyun E-mail: koreasds@naver.com

    2016-02-01

    We discuss a scenario where the DAMA modulation effect is explained by a Weakly Interacting Massive Particle (WIMP) which upscatters inelastically to a heavier state and predominantly couples to the spin of protons. In this scenario constraints from xenon and germanium targets are evaded dynamically, due to the suppression of the WIMP coupling to neutrons, while those from fluorine targets are evaded kinematically, because the minimal WIMP incoming speed required to trigger upscatters off fluorine exceeds the maximal WIMP velocity in the Galaxy, or is very close to it. In this scenario WIMP scatterings off sodium are usually sensitive to the large-speed tail of the WIMP velocity distribution and modulated fractions of the signal close to unity arise in a natural way. On the other hand, a halo-independent analysis with more conservative assumptions about the WIMP velocity distribution allows to extend the viable parameter space to configurations where large modulated fractions are not strictly necessary. We discuss large modulated fractions in the Maxwellian case showing that they imply a departure from the usual cosine time dependence of the expected signal in DAMA. However we explicitly show that the DAMA data is not sensitive to this distortion, both in time and frequency space, even in the extreme case of a 100 % modulated fraction. Moreover the same scenario provides an explanation of the maximum in the energy spectrum of the modulation amplitude detected by DAMA in terms of WIMPs whose minimal incoming speed matches the kinematic threshold for inelastic upscatters. For the elastic case the detection of such maximum suggests an inversion of the modulation phase below the present DAMA energy threshold, while this is not expected for inelastic scattering. This may allow to discriminate between the two scenarios in a future low-threshold analysis of the DAMA data.

  5. Spin-dependent correction to the relativistic-electron mass in QED in the presence of an external electric field

    SciTech Connect

    Lebedev, S. L.

    2011-03-15

    A new expression is found for the spin-dependent contribution {Delta}m{sub s} to the self-energy of an electron moving with a transverse momentum p Up-Tack in an electric field. The structure of an asymptotic expansion of {Delta}m{sub s}(r, {chi}) as a function of two dynamical invariants r = {gamma}{sub Up-Tack }{sup -2} and {chi} = {gamma}{sub Up-Tack} vertical bar {epsilon} vertical bar /{epsilon}{sub c} ({gamma}{sub Up-Tack }{sup 2} {identical_to} 1 + p{sub Up-Tack }{sup 2}/m{sup 2}c{sup 2} and {epsilon}{sub c} {identical_to} m{sup 2}c{sup 3}/ vertical bar e vertical bar Planck-Constant-Over-Two-Pi ) is clarified with the aid of this expression. The expansion of {Delta}m{sub s}(r, {chi}) can be represented in the form of a Taylor series in r, the coefficients in this series, F{sub 0}({chi}), F{sub 1}({chi}), etc., being integrals of the Mellin type. The major coefficient F{sub 0}({chi}) is universal and, in the case of an appropriate interpretation of {chi}, describes well-known spin-dependent corrections to the mass in three different cases of a constant external field (for r {yields} 0). The asymptotic properties of the function F{sub 1}({chi}) are studied in detail, but only order-of-magnitude estimates are obtained for F{sub 2}({chi}) and F{sub 3}({chi}). A comparison of these contributions revealed that, in the semiclassical region {chi} Much-Less-Than 1, r is indeed the parameter of the aforementioned expansion, while, for {chi} Much-Greater-Than 1, the true parameter is r{chi}{sup 2} {identical_to} {beta}{sup 2}. In particular, the anomalous magnetic moment develops, owing to F{sub 1}({chi}), a term that grows logarithmically for {chi} Much-Greater-Than 1, but which does not violate the hierarchy of terms in the Taylor series being considered, provided that {beta} remains smaller than unity.

  6. Perpendicular Giant Magnetoresistance Studies of Spin-Dependent Scattering in Magnetic Multilayers.

    NASA Astrophysics Data System (ADS)

    Yang, Qing

    1995-01-01

    AR in the well defined P state above H_{rm s} states and in the also well defined AP state near H = 0, and examined how well these values of AR are predicted with no adjustable parameters from independent data on Co/Cu and Py/Cu multilayers for the H_{ rm o} and H_{rm s} states. The data and the no-free-parameter predictions agree rather well. Thirdly, we made the first tests of effects on AR of reducing the spin-diffusion length l _sp{sf}{N} by adding impurities to N that flip spins (Mn, by exchange scattering, and Pt, via spin-orbit interactions). Using a theory by Valet and Fert to fit deviations of the square root quantity listed above from a straight line passing through the origin, we isolate effects due to reduced l_sp {sf}{N}. Our values of l_sp{sf}{N} are close to independent estimates. We also measured the first CPP-MRs with the F metal, Ni, finding that the CPP-MRs in Ni/Ag are several times larger than the MRs with Current flow In the layer Planes (CIP-MR), but the CPP-MRs for Ni/Ag are much smaller than those for Co/Ag or Co/Cu. Lastly, we describe preliminary results on some exploratory projects.

  7. 45 CFR 650.6 - Awards not primarily for research.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PATENTS § 650.6 Awards not primarily for research. (a) Awards not primarily intended to support scientific or engineering research need contain no patent provision. Examples of such awards are travel and... 45 Public Welfare 3 2010-10-01 2010-10-01 false Awards not primarily for research. 650.6...

  8. 45 CFR 650.6 - Awards not primarily for research.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... PATENTS § 650.6 Awards not primarily for research. (a) Awards not primarily intended to support scientific or engineering research need contain no patent provision. Examples of such awards are travel and... 45 Public Welfare 3 2013-10-01 2013-10-01 false Awards not primarily for research. 650.6...

  9. Nuclear spin dependence of the reaction of H{sub 3}{sup +} with H{sub 2}. II. Experimental measurements

    SciTech Connect

    Crabtree, Kyle N.; Kauffman, Carrie A.; Tom, Brian A.; Becka, Eftalda; McGuire, Brett A.; McCall, Benjamin J.

    2011-05-21

    The nuclear spin dependence of the chemical reaction H{sub 3}{sup +}+ H{sub 2}{yields} H{sub 2} +H{sub 3}{sup +} has been studied in a hollow cathode plasma cell. Multipass infrared direct absorption spectroscopy has been employed to monitor the populations of several low-energy rotational levels of ortho- and para-H{sub 3}{sup +} (o-H{sub 3}{sup +} and p-H{sub 3}{sup +}) in hydrogenic plasmas of varying para-H{sub 2} (p-H{sub 2}) enrichment. The ratio of the rates of the proton hop (k{sup H}) and hydrogen exchange (k{sup E}) reactions {alpha}{identical_to}k{sup H}/k{sup E} is inferred from the observed p-H{sub 3}{sup +} fraction as a function of p-H{sub 2} fraction using steady-state chemical models. Measurements have been performed both in uncooled (T{sub kin}{approx} 350 K) and in liquid-nitrogen-cooled (T{sub kin}{approx} 135 K) plasmas, marking the first time this reaction has been studied at low temperature. The value of {alpha} has been found to decrease from 1.6 {+-} 0.1 at 350 K to 0.5 {+-} 0.1 at 135 K.

  10. Spin-dependent transport and current-induced spin transfer torque in a disordered zigzag silicene nanoribbon

    NASA Astrophysics Data System (ADS)

    Zhou, Benliang; Zhou, Benhu; Liu, Guang; Guo, Dan; Zhou, Guanghui

    2016-11-01

    We study theoretically the spin-dependent transport and the current-induced spin transfer torque (STT) for a zigzag silicene nanoribbon (ZSiNR) with Anderson-type disorders between two ferromagnetic electrodes. By using the nonequilibrium Green's function method, it is predicted that the transport property and STT through the junction depend sensitively on the disorder, especially around the Dirac point. As a result, the conductance decreases and increases for two electrode in parallel and antiparallel configurations, respectively. Due to the disorder, the magnetoresistance (MR) decreases accordingly even within the energy regime for the perfect plateau without disorders. In addition, the conductance versus the relative angle of the magnetization shows a cosine-like behavior. The STT per unit of the bias voltage versus the angle of the magnetization exhibits a sine-like behavior, and versus the Fermi energy is antisymmetrical to the Dirac point and exhibits sharp peaks. Furthermore, the peaks of the STT are suppressed much as the disorder strength increases, especially around the Dirac point. The results obtained here may provide a valuable suggestion to experimentally design spin valve devices based on ZSiNR.

  11. Effects of line defects on spin-dependent electronic transport of zigzag MoS2 nanoribbons

    NASA Astrophysics Data System (ADS)

    Li, Xin-Mei; Long, Meng-Qiu; Cui, Li-Ling; Yang, Kai-Wei; Zhang, Dan; Ding, Jia-Feng; Xu, Hui

    2016-01-01

    The nonlinear spin-dependent transport properties in zigzag molybdenum-disulfide nanoribbons (ZMNRs) with line defects are investigated systematically using nonequilibrium Green's function method combined with density functional theory. The results show that the line defects can enhance the electronic transfer ability of ZMNRs. The types and locations of the line defects are found critical in determining the spin polarization and the current-voltage (I-V) characteristics of the line defected ZMNRs. For the same defect type, the total currents of the ribbons with the line defects in the centers are lager than those on the edges. And for the same location, the total currents of the systems with the sulfur (S) line defect are larger than the according systems with the molybdenum (Mo) line defect. All the considered systems present magnetism properties. And in the S line defected systems, the spin reversal behaviors can be observed. In both the spin-up and spin-down states of the Mo line defected systems, there are obvious negative differential resistance behaviors. The mechanisms are proposed for these phenomena.

  12. Effects of symmetry and spin configuration on spin-dependent transport properties of iron-phthalocyanine-based devices

    SciTech Connect

    Cui, Li-Ling; Yang, Bing-Chu Li, Xin-Mei; Cao, Can; Long, Meng-Qiu

    2014-07-21

    Spin-dependent transport properties of nanodevices constructed by iron-phthalocyanine (FePc) molecule sandwiched between two zigzag graphene nanoribbon electrodes are studied using first-principles quantum transport calculations. The effects of the symmetry and spin configuration of electrodes have been taken into account. It is found that large magnetoresistance, large spin polarization, dual spin-filtering, and negative differential resistance (NDR) can coexist in these devices. Our results show that 5Z-FePc system presents well conductive ability in both parallel (P) and anti-parallel (AP) configurations. For 6Z-FePc-P system, spin filtering effect and large spin polarization can be found. A dual spin filtering and NDR can also be shown in 6Z-FePc-AP. Our studies indicate that the dual spin filtering effect depends on the orbitals symmetry of the energy bands and spin mismatching of the electrodes. And all the effects would open up possibilities for their applications in spin-valve, spin-filter as well as effective spin diode devices.

  13. Nontrivial spin structure of graphene on Pt(111) at the Fermi level due to spin-dependent hybridization

    NASA Astrophysics Data System (ADS)

    Klimovskikh, I. I.; Tsirkin, S. S.; Rybkin, A. G.; Rybkina, A. A.; Filianina, M. V.; Zhizhin, E. V.; Chulkov, E. V.; Shikin, A. M.

    2014-12-01

    The electronic and spin structure of a graphene monolayer synthesized on Pt(111) has been investigated experimentally by angle- and spin-resolved photoemission with different polarizations of incident synchrotron radiation and using density functional theory calculations. It is shown that despite the observed total quasifreestanding character of the dispersion of the graphene π state remarkable local distortions and breaks in the dispersions take place due to hybridization between the graphene π and Pt d states. Corresponding spin-dependent avoided-crossing effects lead to significant modification of the spin structure and cause an enhanced induced spin-orbit splitting of the graphene π states near the Fermi level in the region of the K ¯ point of the graphene Brillouin zone (BZ) with a magnitude of 80-200 meV depending on the direction in the BZ. Using p , s , and elliptical polarizations of the synchrotron radiation, the contributions of the graphene π and Pt d states were separated and their intersection at the Fermi level, which is important for effective spin injection between these states, was shown. Moreover, analysis of the data allows us to conclude that in the region of the Dirac point the spin structure of the system cannot be described by a Rashba splitting, and even a spin-orbit gap between lower and upper Dirac cones is observed.

  14. Effects of line defects on spin-dependent electronic transport of zigzag MoS{sub 2} nanoribbons

    SciTech Connect

    Li, Xin-Mei; Yang, Kai-Wei; Zhang, Dan; Ding, Jia-Feng; Xu, Hui; Long, Meng-Qiu; Cui, Li-Ling

    2016-01-15

    The nonlinear spin-dependent transport properties in zigzag molybdenum-disulfide nanoribbons (ZMNRs) with line defects are investigated systematically using nonequilibrium Green’s function method combined with density functional theory. The results show that the line defects can enhance the electronic transfer ability of ZMNRs. The types and locations of the line defects are found critical in determining the spin polarization and the current-voltage (I-V) characteristics of the line defected ZMNRs. For the same defect type, the total currents of the ribbons with the line defects in the centers are lager than those on the edges. And for the same location, the total currents of the systems with the sulfur (S) line defect are larger than the according systems with the molybdenum (Mo) line defect. All the considered systems present magnetism properties. And in the S line defected systems, the spin reversal behaviors can be observed. In both the spin-up and spin-down states of the Mo line defected systems, there are obvious negative differential resistance behaviors. The mechanisms are proposed for these phenomena.

  15. Final COMPASS results on the deuteron spin-dependent structure function g1d and the Bjorken sum rule

    NASA Astrophysics Data System (ADS)

    Adolph, C.; Aghasyan, M.; Akhunzyanov, R.; Alexeev, M. G.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C. D. R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S.-U.; Cicuttin, A.; Crespo, M. L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Dhara, L.; Donskov, S. V.; Doshita, N.; Dreisbach, Ch.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P. D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Giarra, J.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F. H.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O. M.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G. K.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G. V.; Meyer, M.; Meyer, W.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A. S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Roskot, M.; Rossiyskaya, N. S.; Ryabchikov, D. I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Thiel, A.; Tosello, F.; Tskhay, V.; Uhl, S.; Vauth, A.; Veloso, J.; Virius, M.; Vondra, J.; Wallner, S.; Weisrock, T.; Wilfert, M.; Windmolders, R.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Zink, A.

    2017-06-01

    Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1(GeV / c) 2 4GeV /c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A1d and the deuteron longitudinal-spin structure function g1d are presented in bins of x and Q2. Towards lowest accessible values of x, g1d decreases and becomes consistent with zero within uncertainties. The presented final g1d values together with the recently published final g1p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0, which is identified in the MS ‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0 (Q2 = 3(GeV / c) 2) = 0.32 ±0.02stat ±0.04syst ±0.05evol. Together with the recent results on the proton spin structure function g1p, the results on g1d constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering.

  16. Angle-resolved photoemission spectra, electronic structure and spin dependent scattering in Ni_1-xFex permalloys

    NASA Astrophysics Data System (ADS)

    Sahrakorpi, S.; Mijnarends, P. E.; Lindroos, M.; Bansil, A.

    2002-03-01

    We present the all electron charge and spin self-consistent electronic structure of Ni_1-xFex permalloys for a range of Fe concentrations, using the first principles Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) scheme to treat disorder and the local spin density (LSD) approximation to incorporate exchange-correlation effects. Recent high resolution angle-resolved photoemission spectroscopy (ARPES) experiments on Ni_0.90Fe_0.10 and Ni_0.80Fe_0.20 permalloys are analyzed in terms of the spectral density function, A_B( k_allel, k_⊥= 0,E_F), computed from the KKR-CPA Green function for k_allel values varying along the Γ-K direction in the Brillouin zone (BZ). The widths of the majority as well as the minority spin peaks in the theoretical spectra are in excellent accord with the corresponding ARPES results in all cases, suggesting that spin-dependent disorder scattering constitutes the main scattering mechanism for the carriers in the permalloys. Majority spin states of Ni are virtually undamped by the Fe impurities, while the minority spins at the Fermi energy (E_F) are heavily damped. The nature of the Ni and Fe potentials in the permalloys is explored in detail. The effective disorder parameter in the alloy is found to be strongly dependent on the energy, momentum, spin and symmetry of the specific states involved. The evolution of the electronic states on the Ni and Fe sites as a function of Fe concentration is discussed. The magnetic moments on Ni as well as on Fe are found to remain essentially unchanged with increasing Fe content.

  17. Effect of MgO/Co interface and Co/MgO interface on the spin dependent transport in perpendicular Co/Pt multilayers

    SciTech Connect

    Zhang, J. Y.; Liu, Y. W.; Zhao, Z. D.; Chen, X.; Feng, C.; Yu, G. H. E-mail: ghyu@mater.ustb.edu.cn; Yang, G.; Wang, S. G. E-mail: ghyu@mater.ustb.edu.cn; Wu, Z. L.; Zhang, S. L.

    2014-10-28

    Effect of the metal/oxide interface on spin-dependent transport properties in perpendicular [Co/Pt]{sub 3} multilayers was investigated. The saturation Hall resistivity (ρ{sub xy}) is significantly increased by 45% with 1.4 nm thick CoO layer inserted at the top Co/MgO interface; whereas it is increased only 25% with 1 nm thick CoO layer at the bottom MgO/Co interface. The interfacial structures characterized by X-ray photoelectron spectroscopy show that the MgO/Co interface and Co/MgO interface including chemical states play a dominant role on spin-dependent transport, leading to different anomalous Hall behavior.

  18. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Spin-dependent electron transport of a waveguide with Rashba spin-orbit coupling in an electromagnetic field

    NASA Astrophysics Data System (ADS)

    Xiao, Xian-Bo; Li, Xiao-Mao; Chen, Yu-Guang

    2009-12-01

    We investigate theoretically the spin-dependent electron transport in a straight waveguide with Rashba spin-orbit coupling (SOC) under the irradiation of a transversely polarized electromagnetic (EM) field. Spin-dependent electron conductance and spin polarization are calculated as functions of the emitting energy of electrons or the strength of the EM field by adopting the mode matching approach. It is shown that the spin polarization can be manipulated by external parameters when the strength of Rashba SOC is strong. Furthermore, a sharp step structure is found to exist in the total electron conductance. These results can be understood by the nontrivial Rashba subbands intermixing and the electron intersubband transition when a finite-range transversely polarized EM field irradiates a straight waveguide.

  19. Effect of magnetic field on spin-dependent hole transport through a type-I Cd1-xMnxTe/CdTe double barrier heterostrucutre

    NASA Astrophysics Data System (ADS)

    Chandrasekar, L. Bruno; Gnanasekar, K.; Karunakaran, M.; Chandramohan, R.

    2017-06-01

    We study the effect of the magnetic field on the spin-dependent hole transport through a diluted magnetic semiconductor double barrier heterostrucutre such as Cd1- x Mn x Te/CdTe. Using the transfer matrix, the barrier transparency, polarization efficiency and tunneling lifetime of a light hole and a heavy hole are calculated. The spin separation is found out and is observed that it is the same for both the light and the heavy hole. The heavy hole takes more time to travel in the heterostrucutre than the light hole. The effect of the magnetic field influences the tunneling lifetime. The results give the basic idea about the spin-dependent transport of light and heavy holes.

  20. Perpendicular Giant Magnetoresistance: Study and Application of Spin Dependent Scattering in Magnetic Multilayers of Cobalt/copper and NICKEL(84) IRON(16)/COPPER

    NASA Astrophysics Data System (ADS)

    Holody, Paul Robert Joseph

    Perpendicular transport through magnetic multilayers has been successfully described by the two spin channel model. In the limit where spin flip scattering can be neglected, the transport current is carried by parallel channels of spin up and spin down electrons. Large negative magnetoresistances arise from spin dependent scattering occurring in these channels. Electrons with spins parallel to the local magnetization undergo a different amount of scattering from those with spins antiparallel to the local magnetization. Consequently the multilayer's resistance can be controlled by the relative orientation of the ferromagnetic layers' magnetizations. Usually with the relative orientation antiparallel (parallel) the multilayer has a high (low) resistance. In this dissertation, an analysis of perpendicular transport measurements in the context of the two spin channel model provides quantitative information about the amounts of spin dependent scattering at the Ferromagnetic/Normal metal interfaces and in the bulk Ferromagnet metal for the Co/Cu and Ni_{84}Fe _{16}/Cu systems (Ni_{84}Fe_{16}=Py). This is essential to the understanding of the scattering mechanisms involved in Giant Magnetoresistance. Our results show a significant bulk contribution to the spin dependent scattering; but, it is the interfaces which make the larger contribution to spin dependent scattering in these systems. A larger bulk spin dependent scattering asymmetry was determined for the Py/Cu multilayers, but not as large as expected from data derived previously from ternary alloys. Measurements were made on several Co/CuX series (where X = Pt, Mn, Ge and Ni) to study the transport properties of magnetic multilayers when significant spin flip scattering is present in the system. Analysis was done using the Valet-Fert theory which generalizes the two spin channel model to include finite spin diffusion lengths. A sharp drop in the magnetoresistance is observed when the spin diffusion length ~ layer

  1. Morphological Effects on Spin-Dependent Electronic Processes in Poly[9,9-Dioctylfluorenyl-2,7-Diyl] Thin Film Organic Light Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Miller, Richards G., III

    The goal of the work presented in this dissertation was to find out how physical ordering of organic semiconductors affects spin-dependent electronic charge carrier transitions. Organic light emitting diodes in distinct morphological phases were created out of thin films of the pi-conjugated polymer poly[9,9-dioctylfluorenyl-2,7-diyl] (polyfluorene), allowing diodes to be studied with the sole difference being the degree of polymeric order in the active layer of the device. The polyfluorene morphologies studied ranged from an amorphous (glassy) phase through mixed phases, to a highly ordered (beta) phase. The phase control was achieved through a dipping procedure where a glassy polyfluorene layer is immersed in a solvent mixture that structures the side chains of a monomer unit into an alternating planar ladder structure. Continuous-wave (cw) and pulsed (p) electrically detected magnetic resonance (EDMR) spectroscopies were used to probe charge carrier spin states within the polyfluorene layers. For cw EDMR, microwave frequencies between 1 and 20 GHz were used, while all pEDMR measurements were conducted at X-band ( 9.6 GHz). The experiments allowed for a comparison of how polymer morphology affects spin-dependent charge carrier transitions, coherent spin motion, spin relaxation times, the local nuclear (hyperfine) magnetic fields and spin-orbit effects. In addition to film morphology, temperature and device-bias dependencies of the spin-dependent charge carrier transitions were studied experimentally and a set of global fit and bootstrap error analysis techniques were adapted for EDMR spectroscopy.

  2. The constraint on the spin dependent structure function g1 at low Q2 through the sum rule corresponding to the moment at n = 0

    NASA Astrophysics Data System (ADS)

    Koretune, Susumu

    2007-06-01

    The sum rules for the spin dependent structure function g1ab in the null-plane formalism corresponding to the moment at n = 0 has been transformed to the sum rule which relates the g1ab with the cross section of the isovector photon or the real photon. Based on these sum rules, we argue that there is a deep connection among the elastic, the resonance, and the non-resonant contributions, and that it explains why the sign of the generalized Gerasimov-Drell-Hern sum changes at very small Q2.

  3. 45 CFR 650.6 - Awards not primarily for research.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 3 2014-10-01 2014-10-01 false Awards not primarily for research. 650.6 Section 650.6 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION...: Intellectual Property Rights The National Science Foundation claims no rights to any inventions or...

  4. 45 CFR 650.6 - Awards not primarily for research.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Awards not primarily for research. 650.6 Section 650.6 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION...: Intellectual Property Rights The National Science Foundation claims no rights to any inventions or...

  5. Building Community: When Public Relations Is Primarily an Interpersonal Experience.

    ERIC Educational Resources Information Center

    Neff, Bonita Dostal

    Public relations textbooks and the literature in public relations do not discuss issues management (IM) in terms of nonprofit organizations, focusing instead primarily on corporate activity. Yet nonprofits have serious need for IM, particularly since it is the nonprofits that will be providing the leadership in diversity and multicultural efforts…

  6. 45 CFR 650.6 - Awards not primarily for research.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Awards not primarily for research. 650.6 Section 650.6 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION...: Intellectual Property Rights The National Science Foundation claims no rights to any inventions or...

  7. Spin-dependent transport behavior in C{sub 60} and Alq{sub 3} based spin valves with a magnetite electrode (invited)

    SciTech Connect

    Zhang, Xianmin Mizukami, Shigemi; Ma, Qinli; Kubota, Takahide; Miyazaki, Terunobu; Oogane, Mikihiko; Naganuma, Hiroshi; Ando, Yasuo

    2014-05-07

    The spin-dependent transport behavior in organic semiconductors (OSs) is generally observed at low temperatures, which likely results from poor spin injection efficiency at room temperature from the ferromagnetic metal electrodes to the OS layer. Possible reasons for this are the low Curie temperature and/or the small spin polarization efficiency for the ferromagnetic electrodes used in these devices. Magnetite has potential as an advanced candidate for use as the electrode in spintronic devices, because it can achieve 100% spin polarization efficiency in theory, and has a high Curie temperature (850 K). Here, we fabricated two types of organic spin valves using magnetite as a high efficiency electrode. C{sub 60} and 8-hydroxyquinoline aluminum (Alq{sub 3}) were employed as the OS layers. Magnetoresistance ratios of around 8% and over 6% were obtained in C{sub 60} and Alq{sub 3}-based spin valves at room temperature, respectively, which are two of the highest magnetoresistance ratios in organic spin valves reported thus far. The magnetoresistance effect was systemically investigated by varying the thickness of the Alq{sub 3} layer. Moreover, the temperature dependence of the magnetoresistance ratios for C{sub 60} and Alq{sub 3}-based spin valves were evaluated to gain insight into the spin-dependent transport behavior. This study provides a useful method in designing organic spin devices operated at room temperature.

  8. Careers in Virology: Teaching at a Primarily Undergraduate Institution

    PubMed Central

    2014-01-01

    A faculty position at a primarily undergraduate institution requires working with undergraduates in both the classroom and the research lab. Graduate students and postdoctoral fellows who are interested in such a career should understand that faculty at these institutions need to teach broadly and devise research questions that can be addressed safely and with limited resources compared to a research I university. Aspects of, and ways to prepare for, this career will be reviewed herein. PMID:25056885

  9. Careers in virology: teaching at a primarily undergraduate institution.

    PubMed

    Kushner, David B

    2014-10-01

    A faculty position at a primarily undergraduate institution requires working with undergraduates in both the classroom and the research lab. Graduate students and postdoctoral fellows who are interested in such a career should understand that faculty at these institutions need to teach broadly and devise research questions that can be addressed safely and with limited resources compared to a research I university. Aspects of, and ways to prepare for, this career will be reviewed herein.

  10. Spin-dependent quantum interference in Aharonov-Bohm ring embedded with two double-quantum-dot molecules.

    PubMed

    Wang, Xiaofei; Liu, Xiaojie; Zhao, Xueyang; Yin, Haitao; Wan, Weilong; Feng, Li

    2014-03-01

    The spin polarized transport properties through an Aharonov-Bohm ring embedded with a double quantum dot-molecule in each arm with Rashba spin-orbit (RSO) interaction is theoretically studied in the framework of the equation of motion of Green's function. Based on molecular state representation, the anti-resonance phenomenon in the conductance spectrum is readily explained. We found that the position of antiresonant peaks in conductance spectrum is determined by the interdot coupling strengths. Moreover, the magnitude of conductance of each spin component can be manipulated by the Rashba spin orbit interaction strength. Especially only one spin component electron can be allowed to transport through this structure by modulating the strength of RSO interaction properly.

  11. Electron-nuclear spin dynamics of Ga2 + paramagnetic centers probed by spin-dependent recombination: A master equation approach

    NASA Astrophysics Data System (ADS)

    Ibarra-Sierra, V. G.; Sandoval-Santana, J. C.; Azaizia, S.; Carrère, H.; Bakaleinikov, L. A.; Kalevich, V. K.; Ivchenko, E. L.; Marie, X.; Amand, T.; Balocchi, A.; Kunold, A.

    2017-05-01

    Similar to nitrogen-vacancy centers in diamond and impurity atoms in silicon, interstitial gallium deep paramagnetic centers in GaAsN have been proven to have useful characteristics for the development of spintronic devices. Among other interesting properties, under circularly polarized light, gallium centers act as spin filters that dynamically polarize free and bound electrons reaching record spin polarizations (close to 100%). Furthermore, the recent observation of the amplification of the spin filtering effect under a Faraday configuration magnetic field has suggested that the hyperfine interaction that couples bound electrons and nuclei permits the optical manipulation of the nuclear spin polarization. Even though the mechanisms behind the nuclear spin polarization in gallium centers are fairly well understood, the origin of nuclear spin relaxation and the formation of an Overhauser-like magnetic field remain elusive. In this work we develop a model based on the master equation approach to describe the evolution of electronic and nuclear spin polarizations of gallium centers interacting with free electrons and holes. Our results are in good agreement with existing experimental observations. In particular, we are able to reproduce the amplification of the spin filtering effect under a circularly polarized excitation in a Faraday configuration magnetic field. In regard to the nuclear spin relaxation, the roles of nuclear dipolar and quadrupolar interactions are discussed. Our findings show that, besides the hyperfine interaction, the spin relaxation mechanisms are key to understand the amplification of the spin filtering effect and the appearance of the Overhauser-like magnetic field. To gain a deeper insight in the interplay of the hyperfine interaction and the relaxation mechanisms, we have also performed calculations in the pulsed excitation regime. Our model's results allow us to propose an experimental protocol based on time-resolved spectroscopy. It

  12. Effect of interfacial structures on spin dependent tunneling in epitaxial L10-FePt/MgO/FePt perpendicular magnetic tunnel junctions

    NASA Astrophysics Data System (ADS)

    Yang, G.; Li, D. L.; Wang, S. G.; Ma, Q. L.; Liang, S. H.; Wei, H. X.; Han, X. F.; Hesjedal, T.; Ward, R. C. C.; Kohn, A.; Elkayam, A.; Tal, N.; Zhang, X.-G.

    2015-02-01

    Epitaxial FePt(001)/MgO/FePt magnetic tunnel junctions with L10-FePt electrodes showing perpendicular magnetic anisotropy were fabricated by molecular beam epitaxial growth. Tunnel magnetoresistance ratios of 21% and 53% were obtained at 300 K and 10 K, respectively. Our previous work, based on transmission electron microscopy, confirmed a semi-coherent interfacial structure with atomic steps (Kohn et al., APL 102, 062403 (2013)). Here, we show by x-ray photoemission spectroscopy and first-principles calculation that the bottom FePt/MgO interface is either Pt-terminated for regular growth or when an Fe layer is inserted at the interface, it is chemically bonded to O. Both these structures have a dominant role in spin dependent tunneling across the MgO barrier resulting in a decrease of the tunneling magnetoresistance ratio compared with previous predictions.

  13. Spin dependent recombination; A sup 29 Si hyperfine study of radiation-induced P sub b centers at the Si/SiO sub 2 interface

    SciTech Connect

    Jupina, M.A.; Lenahan, P.M. )

    1990-12-01

    The spin dependent recombination (SDR) technique is used to observe the {sup 29}Si hyperfine spectra of radiation-induced P{sub b} centers at the Si/SiO{sub 2} interface in a MOSFET. The P{sub b} center is a paramagnetic, trivalent silicon defect that is the dominant radiation-induced interface state. The {sup 29}Si hyperfine spectra give detailed atomic scale information about the P{sub b} center. The authors' SDR results show that the {sup 29}Si hyperfine spectra vary with surface potential. This result indicates that differences in the defect's local geometry lead to substantial differences in the defect's energy level. However, the {sup 29}Si hyperfine spectra are found to be relatively independent of the ionizing radiation dosage.

  14. Effects of V-shaped edge defect and H-saturation on spin-dependent electronic transport of zigzag MoS2 nanoribbons

    NASA Astrophysics Data System (ADS)

    Li, Xin-Mei; Long, Meng-Qiu; Cui, Li-Ling; Xiao, Jin; Zhang, Xiao-Jiao; Zhang, Dan; Xu, Hui

    2014-07-01

    Based on nonequilibrium Green's function in combination with density functional theory calculations, the spin-dependent electronic transport properties of one-dimensional zigzag molybdenum disulfide (MoS2) nanoribbons with V-shaped defect and H-saturation on the edges have been studied. Our results show that the spin-polarized transport properties can be found in all the considered zigzag MoS2 nanoribbons systems. The edge defects, especially the V-shaped defect on the Mo edge, and H-saturation on the edges can suppress the electronic transport of the systems. Also, the spin-filtering and negative differential resistance behaviors can be observed obviously. The mechanisms are proposed for these phenomena.

  15. Universal formulation of second-order generalized Møller-Plesset perturbation theory for a spin-dependent two-component relativistic many-electron Hamiltonian

    NASA Astrophysics Data System (ADS)

    Nakano, Masahiko; Seino, Junji; Nakai, Hiromi

    2017-05-01

    We have derived and implemented a universal formulation of the second-order generalized Møller-Plesset perturbation theory (GMP2) for spin-dependent (SD) two-component relativistic many-electron Hamiltonians, such as the infinite-order Douglas-Kroll-Hess Hamiltonian for many-electron systems, which is denoted as IODKH/IODKH. Numerical assessments for He- and Ne-like atoms and 16 diatomic molecules show that the MP2 correlation energies with IODKH/IODKH agree well with those calculated with the four-component Dirac-Coulomb (DC) Hamiltonian, indicating a systematic improvement on the inclusion of relativistic two-electron terms. The present MP2 scheme for IODKH/IODKH is demonstrated to be computationally more efficient than that for DC.

  16. Spin-dependent transport properties of a GaMnAs-based vertical spin metal-oxide-semiconductor field-effect transistor structure

    SciTech Connect

    Kanaki, Toshiki Asahara, Hirokatsu; Ohya, Shinobu Tanaka, Masaaki

    2015-12-14

    We fabricate a vertical spin metal-oxide-semiconductor field-effect transistor (spin-MOSFET) structure, which is composed of an epitaxial single-crystal heterostructure with a ferromagnetic-semiconductor GaMnAs source/drain, and investigate its spin-dependent transport properties. We modulate the drain-source current I{sub DS} by ∼±0.5% with a gate-source voltage of ±10.8 V and also modulate I{sub DS} by up to 60% with changing the magnetization configuration of the GaMnAs source/drain at 3.5 K. The magnetoresistance ratio is more than two orders of magnitude higher than that obtained in the previous studies on spin MOSFETs. Our result shows that a vertical structure is one of the hopeful candidates for spin MOSFET when the device size is reduced to a sub-micron or nanometer scale.

  17. Effect of interfacial structures on spin dependent tunneling in epitaxial L1{sub 0}-FePt/MgO/FePt perpendicular magnetic tunnel junctions

    SciTech Connect

    Yang, G.; Li, D. L.; Wang, S. G. Ma, Q. L.; Liang, S. H.; Wei, H. X.; Han, X. F.; Hesjedal, T.; Ward, R. C. C.; Kohn, A.; Elkayam, A.; Tal, N.; Zhang, X.-G.

    2015-02-28

    Epitaxial FePt(001)/MgO/FePt magnetic tunnel junctions with L1{sub 0}-FePt electrodes showing perpendicular magnetic anisotropy were fabricated by molecular beam epitaxial growth. Tunnel magnetoresistance ratios of 21% and 53% were obtained at 300 K and 10 K, respectively. Our previous work, based on transmission electron microscopy, confirmed a semi-coherent interfacial structure with atomic steps (Kohn et al., APL 102, 062403 (2013)). Here, we show by x-ray photoemission spectroscopy and first-principles calculation that the bottom FePt/MgO interface is either Pt-terminated for regular growth or when an Fe layer is inserted at the interface, it is chemically bonded to O. Both these structures have a dominant role in spin dependent tunneling across the MgO barrier resulting in a decrease of the tunneling magnetoresistance ratio compared with previous predictions.

  18. Human punishment is not primarily motivated by inequality

    PubMed Central

    Marczyk, Jesse

    2017-01-01

    Previous theorizing about punishment has suggested that humans desire to punish inequality per se. However, the research supporting such an interpretation contains important methodological confounds. The main objective of the current experiment was to remove those confounds in order to test whether generating inequality per se is punished. Participants were recruited from an online market to take part in a wealth-alteration game with an ostensible second player. The participants were given an option to deduct from the other player’s payment as punishment for their behavior during the game. The results suggest that human punishment does not appear to be motivated by inequality per se, as inequality that was generated without inflicting costs on others was not reliably punished. Instead, punishment seems to respond primarily to the infliction of costs, with inequality only becoming relevant as a secondary input for punishment decisions. The theoretical significance of this finding is discussed in the context of its possible adaptive value. PMID:28187166

  19. Human punishment is not primarily motivated by inequality.

    PubMed

    Marczyk, Jesse

    2017-01-01

    Previous theorizing about punishment has suggested that humans desire to punish inequality per se. However, the research supporting such an interpretation contains important methodological confounds. The main objective of the current experiment was to remove those confounds in order to test whether generating inequality per se is punished. Participants were recruited from an online market to take part in a wealth-alteration game with an ostensible second player. The participants were given an option to deduct from the other player's payment as punishment for their behavior during the game. The results suggest that human punishment does not appear to be motivated by inequality per se, as inequality that was generated without inflicting costs on others was not reliably punished. Instead, punishment seems to respond primarily to the infliction of costs, with inequality only becoming relevant as a secondary input for punishment decisions. The theoretical significance of this finding is discussed in the context of its possible adaptive value.

  20. Spin-Dependent Electron Scattering from Polarized Protons and Deuterons with the BLAST Experiment at MIT-Bates

    NASA Astrophysics Data System (ADS)

    Hasell, Douglas K.; Milner, Richard G.; Redwine, Robert P.; Alarcon, Ricardo; Gao, Haiyan; Kohl, Michael; Calarco, John R.

    2011-11-01

    The Bates Large Acceptance Spectrometer Toroid (BLAST) experiment was operated at the MIT-Bates Linear Accelerator Center from 2003 until 2005. The experiment was designed to exploit the power of a polarized electron beam incident on polarized targets of hydrogen and deuterium to measure, in a systematic manner, the neutron, proton, and deuteron form factors as well as other aspects of the electromagnetic interaction on few-nucleon systems. We briefly describe the experiment, and present and discuss the numerous results obtained.

  1. Spin-dependent transport caused by the local magnetic moments inserted in the Aharonov-Bohm rings.

    PubMed

    Shelykh, I A; Kulov, M A; Galkin, N G; Bagraev, N T

    2007-06-20

    We analyse the conductance of an Aharonov-Bohm (AB) ring with a quantum point contact (QPC) that is inserted in one of its arms and which contains a single electron. The conductance of the device is calculated as a function of the one-dimensional (1D) carrier concentration and the value of the magnetic field perpendicular to the plane of the AB ring. The exchange interaction between the electron localized inside QPC and freely propagating electrons is shown to modify the conductance pattern at small carrier concentration significantly, giving rise to the effects related to the formation of the '0.7 feature' in the quantum conductance staircase.

  2. Primarily nonlinear effects observed in a driven asymmetrical vibrating wire

    NASA Astrophysics Data System (ADS)

    Hanson, Roger J.; Macomber, H. Kent; Morrison, Andrew C.; Boucher, Matthew A.

    2005-01-01

    The purpose of the work reported here is to further experimentally explore the wide variety of behaviors exhibited by driven vibrating wires, primarily in the nonlinear regime. When the wire is driven near a resonant frequency, it is found that most such behaviors are significantly affected by the splitting of the resonant frequency and by the existence of a ``characteristic'' axis associated with each split frequency. It is shown that frequency splitting decreases with increasing wire tension and can be altered by twisting. Two methods are described for determining the orientation of characteristic axes. Evidence is provided, with a possible explanation, that each axis has the same orientation everywhere along the wire. Frequency response data exhibiting nonlinear generation of transverse motion perpendicular to the driving direction, hysteresis, linear generation of perpendicular motion (sometimes tubular), and generation of motion at harmonics of the driving frequency are exhibited and discussed. Also reported under seemingly unchanging conditions are abrupt large changes in the harmonic content of the motion that sometimes involve large subharmonics and harmonics thereof. Slow transitions from one stable state of vibration to another and quasiperiodic motions are also exhibited. Possible musical significance is discussed. .

  3. Cryopreservation of primarily isolated porcine hepatocytes with UW solution.

    PubMed

    Kunieda, Takemi; Maruyama, Masanobu; Okitsu, Teru; Shibata, Norikuni; Takesue, Michihiko; Totsugawa, Toshinori; Kosaka, Yoshikazu; Arata, Takashi; Kobayashi, Kazuya; Ikeda, Hideaki; Oshita, Mizuko; Nakaji, Shuhei; Ohmoto, Kenji; Yamamoto, Shinichiro; Kurabayashi, Yuzuru; Kodama, Makoto; Tanaka, Noriaki; Kobayashi, Naoya

    2003-01-01

    Development of liver-targeted cell therapies, such as hepatocyte transplantation and bioartificial livers, requires a large amount of functional hepatocytes as needed. To achieve this development, establishing an excellent cryopreservation method of hepatocytes is an extremely important issue. Therefore, we performed a comparative review of cryoprotective effects of various cryopreservation solutions using primarily isolated porcine hepatocytes. Porcine hepatocytes were isolated with a four-step dispase and collagenase perfusion method. The obtained hepatocytes with the initial viabilities of 76%, 84%, and 96% were assigned to the following four groups for cryopreservation at -80 degrees C: Dulbecco's modified Eagle's medium (DMEM) + 10% fetal bovine serum (FBS) + 12% dimethyl sulfoxide (DMSO) (group A), University of Wisconsin (UW) solution + 12% DMSO (group B), Cell Banker 1 (group C), and Cell Banker 2 (group D). The hepatocytes in each group were thawed at 3 days, 10 days, and 5 months of cryopreservation and subjected to comparative analyses, including viability, plating efficiency, LDH release, ammonia removal test, and lentiviral gene transfer. These parameters were the most favorable in the hepatocytes cryopreserved with UW solution. Approximately 5% of thawed cryopreserved porcine hepatocytes expressed LacZ activity after lentiviral transduction. Intrasplenic transplantation of UW solution-cryopreserved hepatocytes improved the survival of rats treated with D-galactosamine. UW solution maintained the functions of cryopreserved porcine hepatocytes.

  4. Search for spin-dependent short-range force between nucleons using optically polarized He3 gas

    NASA Astrophysics Data System (ADS)

    Zheng, W.; Gao, H.; Lalremruata, B.; Zhang, Y.; Laskaris, G.; Snow, W. M.; Fu, C. B.

    2012-02-01

    We propose a new method to detect short-range P- and T-violating interactions between nucleons, based on measuring the precession frequency shift of polarized He3 nuclei in the presence of an unpolarized mass. To maximize the sensitivity, a high-pressure He3 cell with thin glass windows (250μm) is used to minimize the distance between the mass and He3. The magnetic field fluctuation is suppressed by using the He3 gas in a different region of the cell as a magnetometer. Systematic uncertainties from the magnetic properties of the mass are suppressed by flipping both the magnetic field and spin directions. Without any magnetic shielding, our result has already reached the sensitivity of the current best limit. With improvement in uniformity and stability of the field, we can further improve the sensitivity by 2 orders of magnitude over the force range from 10-4-10-2m.

  5. Pathogenic Leptospira interrogans Exoproteins Are Primarily Involved in Heterotrophic Processes

    PubMed Central

    Eshghi, Azad; Pappalardo, Elisa; Hester, Svenja; Thomas, Benjamin; Pretre, Gabriela

    2015-01-01

    Leptospirosis is a life-threatening and emerging zoonotic disease with a worldwide annual occurrence of more than 1 million cases. Leptospirosis is caused by spirochetes belonging to the genus Leptospira. The mechanisms of disease manifestation in the host remain elusive, and the roles of leptospiral exoproteins in these processes have yet to be determined. Our aim in this study was to assess the composition and quantity of exoproteins of pathogenic Leptospira interrogans and to construe how these proteins contribute to disease pathogenesis. Label-free quantitative mass spectrometry of proteins obtained from Leptospira spirochetes cultured in vitro under conditions mimicking infection identified 325 exoproteins. The majority of these proteins are conserved in the nonpathogenic species Leptospira biflexa, and proteins involved in metabolism and energy-generating functions were overrepresented and displayed the highest relative abundance in culture supernatants. Conversely, proteins of unknown function, which represent the majority of pathogen-specific proteins (presumably involved in virulence mechanisms), were underrepresented. Characterization of various L. interrogans exoprotein mutants in the animal infection model revealed host mortality rates similar to those of hosts infected with wild-type L. interrogans. Collectively, these results indicate that pathogenic Leptospira exoproteins primarily function in heterotrophic processes (the processes by which organisms utilize organic substances as nutrient sources) to maintain the saprophytic lifestyle rather than the virulence of the bacteria. The underrepresentation of proteins homologous to known virulence factors, such as toxins and effectors in the exoproteome, also suggests that disease manifesting from Leptospira infection is likely caused by a combination of the primary and potentially moonlight functioning of exoproteins. PMID:25987703

  6. Universal dynamics of spontaneous Lorentz violation and a new spin-dependent inverse-square law force

    NASA Astrophysics Data System (ADS)

    Arkani-Hamed, Nima; Cheng, Hsin-Chia; Luty, Markus; Thaler, Jesse

    2005-07-01

    We study the universal low-energy dynamics associated with the spontaneous breaking of Lorentz invariance down to spatial rotations. The effective lagrangian for the associated Goldstone field can be uniquely determined by the non-linear realization of a broken time diffeomorphism symmetry, up to some overall mass scales. It has previously been shown that this symmetry breaking pattern gives rise to a Higgs phase of gravity, in which gravity is modified in the infrared. In this paper, we study the effects of direct couplings between the Goldstone boson and standard model fermions, which necessarily accompany Lorentz-violating terms in the theory. The leading interaction is the coupling to the axial vector current, which reduces to spin in the non-relativistic limit. A spin moving relative to the ``ether" rest frame will emit Goldstone Cerenkov radiation. The Goldstone also induces a long-range inverse-square law force between spin sources with a striking angular dependence, reflecting the underlying Goldstone shockwaves and providing a smoking gun for this theory. We discuss the regime of validity of the effective theory describing these phenomena, and the possibility of probing Lorentz violations through Goldstone boson signals in a way that is complementary to direct tests in some regions of parameter space.

  7. Temperature dependence of spin-dependent tunneling conductance of magnetic tunnel junctions with half-metallic C o2MnSi electrodes

    NASA Astrophysics Data System (ADS)

    Hu, Bing; Moges, Kidist; Honda, Yusuke; Liu, Hong-xi; Uemura, Tetsuya; Yamamoto, Masafumi; Inoue, Jun-ichiro; Shirai, Masafumi

    2016-09-01

    In order to elucidate the origin of the temperature (T ) dependence of spin-dependent tunneling conductance (G ) of magnetic tunnel junctions (MTJs), we experimentally investigated the T dependence of G for the parallel and antiparallel magnetization alignments, GP and GAP, of high-quality C o2MnSi (CMS)/MgO/CMS MTJs having systematically varied spin polarizations (P ) at 4.2 K by varying the Mn composition α in C o2M nαSi electrodes that exhibited giant tunneling magnetoresistance ratios. Results showed that GP normalized by its value at 4.2 K exhibited a notable, nonmonotonic T dependence although its variation with T was significantly smaller than that of GAP normalized by its value at 4.2 K, indicating that an analysis of the experimental GP(T ) is critical to revealing the origin of the T dependence of G . By analyzing the experimental GP(T ) , we clarified that both spin-flip inelastic tunneling via a thermally excited magnon and spin-conserving elastic tunneling in which P decays with increasing T play key roles. The experimental GAP(T ) , including its stronger T dependence for higher P at 4.2 K, was also consistently explained with this model. Our findings provide a unified picture for understanding the origin of the T dependence of G of MTJs with a wide range of P , including MTJs with high P close to a half-metallic value.

  8. Next-to-leading order corrections to the spin-dependent energy spectrum of hadrons from polarized top quark decay in the general two Higgs doublet model

    NASA Astrophysics Data System (ADS)

    Moosavi Nejad, S. Mohammad; Abbaspour, S.

    2017-08-01

    In recent years, searches for the light and heavy charged Higgs bosons have been done by the ATLAS and the CMS collaborations at the Large Hadron Collider (LHC) in proton-proton collision. Nevertheless, a definitive search is a program that still has to be carried out at the LHC. The experimental observation of charged Higgs bosons would indicate physics beyond the Standard Model. In the present work, we study the scaled-energy distribution of bottom-flavored mesons (B) inclusively produced in polarized top quark decays into a light charged Higgs boson and a massless bottom quark at next-to-leading order in the two-Higgs-doublet model; t (↑) → bH+ → BH+ + X. This spin-dependent energy distribution is studied in a specific helicity coordinate system where the polarization vector of the top quark is measured with respect to the direction of the Higgs momentum. The study of these energy distributions could be considered as a new channel to search for the charged Higgs bosons at the LHC. For our numerical analysis and phenomenological predictions, we restrict ourselves to the unexcluded regions of the MSSM mH+ - tan ⁡ β parameter space determined by the recent results of the CMS [13] and ATLAS [14] collaborations.

  9. Ultrafast demagnetization, spin-dependent Seebeck effect, and thermal spin transfer torque in Pt/TbFe/Cu and Pt/TbFe/Cu/Fe thin films

    NASA Astrophysics Data System (ADS)

    Kimling, Johannes; Hebler, Birgit; Kimling, Judith; Albrecht, Manfred; Cahill, David G.

    We investigate diffusive spin currents in Pt(20nm)/TbFe(10nm)/Cu(100nm) and Pt(20 nm)/TbFe(10nm)/ Cu(100nm)/Fe(3nm) stacks using time-resolved magneto-optic Kerr effect (TRMOKE) and time-domain thermoreflectance measurements. Our experiments are based on two hypothesis: (1) fast changes of magnetization due to laser excitation are transferred into spin accumulation, e.g., via electron-magnon scattering; the generated spin accumulation drives a diffusive spin current into adjacent normal metal layers; (2) electronic thermal transport through the ferromagnetic layer injects a spin current into adjacent normal metal layers, based on the spin-dependent Seebeck effect. We excite the Pt layer with ps-laser pulses. Resulting diffusive spin currents generate nonequilibrium magnetization in the Cu layer (sample I) and induce a precession of the magnetization of the Fe layer via spin transfer torque (sample II). Both responses are probed using TRMOKE. Prior experiments used [Co(0.2nm)/Pt(0.4nm)]x5/Co(0.2nm) instead of TbFe. The ferrimagnetic TbFe layer with introduces two major modifications: (1) slow demagnetization behavior, and (2) large thermal resistance. Hence, thermal spin transfer torques can be observed on significantly longer time scales. Financial support by the German Research Foundation under DFG-Grant No. KI 1893/1-1 and DFG-Grant No. AL 618/21-1 are kindly acknowledged.

  10. Toward a computational description of nitrile hydratase: studies of the ground state bonding and spin-dependent energetics of mononuclear, non-heme Fe(III) complexes.

    PubMed

    Chang, Christopher H; Boone, Amy J; Bartlett, Rodney J; Richards, Nigel G J

    2004-01-26

    The metal coordination and spin state of the Fe(III) center in nitrile hydratase (NHase) has stimulated the synthesis of model complexes in efforts to understand the reactivity and spectroscopic properties of the enzyme. We report density functional theory (DFT) calculations on a number of Fe(III) complexes that have been prepared as models of the NHase metal center, together with others having similar ligands but different ground state spin multiplicities. Our results suggest that a DFT description of specific spin configurations in these systems does not suffer from significant amounts of spin contamination. In particular, B3LYP calculations not only reproduce the observed spin state preferences of these Fe(III) complexes but also predict spin-dependent structural properties consistent with those expected on the basis of ligand field models. An analysis of the natural bond orbital (NBO) transformation of the Kohn-Sham wave functions has enabled quantitation of the overall contribution to covalency of ligand-to-metal sigma-donation and pi-donation, and metal-to-ligand pi-back-bonding in these Fe(III) complexes at their BLYP-optimized geometries. Although sulfur ligands are the primary source of covalency in the Fe(III) complexes, our quantitative analysis suggests that hyperbonding between metal-bound nitrogens and an Fe-S bond represents a mechanism by which Fe-N covalency may arise. These studies establish the computational methodology for future theoretical investigations of the NHase Fe(III) center.

  11. Forward jet-like event spin-dependent properties in polarized p + p collisions at √s = 200 GeV

    NASA Astrophysics Data System (ADS)

    Poljak, N.; STAR Collaboration

    2011-05-01

    The STAR collaboration has reported precision measurements on the transverse single spin asymmetries for the production of forward π0 mesons from polarized proton collisions at √s = 200 GeV. To disentangle the contributions to forward asymmetries, one has to look beyond inclusive π0 production to the production of forward jets or direct photons. Present forward detector capabilities are not well matched to the complete reconstruction of forward jets, but do have sufficient acceptance for "jet-like" events."Jet-like" events are the clustered response of an electromagnetic calorimeter that is primarily sensitive to incident photons, electrons and positrons. During the RHIC running in the year 2006, STAR with the Forward Pion Detector (FPD++) in place collected 6.8 pb-1 of data with an average polarization of 60 %. FPD++ was a modular detector prototype of the Forward Meson Spectrometer (FMS) that consisted of two detectors placed symmetrically with respect to the beam line at a distance of 7.4 m from the interaction point. Readout of the FPD++ was triggered when the sum of energies in the central module of the calorimeter used for π0 measurements was larger than a threshold. This trigger minimizes the bias for "jet-like" events, making it appropriate to disentangling contributions to the forward transverse spin asymmetries. We report on the status of the analysis.

  12. Nuclear spin dependence of the reaction of H{sub 3}{sup +} with H{sub 2}. I. Kinetics and modeling

    SciTech Connect

    Crabtree, Kyle N.; Tom, Brian A.; McCall, Benjamin J.

    2011-05-21

    The chemical reaction H{sub 3}{sup +}+ H{sub 2}{yields} H{sub 2}+H{sub 3}{sup +} is the simplest bimolecular reaction involving a polyatomic, yet is complex enough that exact quantum mechanical calculations to adequately model its dynamics are still unfeasible. In particular, the branching fractions for the ''identity,''''proton hop,'' and ''hydrogen exchange'' reaction pathways are unknown, and to date, experimental measurements of this process have been limited. In this work, the nuclear-spin-dependent steady-state kinetics of the H{sub 3}{sup +}+ H{sub 2} reaction is examined in detail, and employed to generate models of the ortho:para ratio of H{sub 3}{sup +} formed in plasmas of varying ortho:para H{sub 2} ratios. One model is based entirely on nuclear spin statistics, and is appropriate for temperatures high enough to populate a large number of H{sub 3}{sup +} rotational states. Efforts are made to include the influence of three-body collisions in this model by deriving nuclear spin product branching fractions for the H{sub 5}{sup +}+ H{sub 2} reaction. Another model, based on rate coefficients calculated using a microcanonical statistical approach, is appropriate for lower-temperature plasmas in which energetic considerations begin to compete with the nuclear spin branching fractions. These models serve as a theoretical framework for interpreting the results of laboratory studies on the reaction of H{sub 3}{sup +} with H{sub 2}.

  13. Enhanced spin-dependent parity-nonconservation effect in the 7 s 1/2 2S →6 d 5/2 2D transition in Fr: A possibility for unambiguous detection of the nuclear anapole moment

    NASA Astrophysics Data System (ADS)

    Sahoo, B. K.; Aoki, T.; Das, B. P.; Sakemi, Y.

    2016-03-01

    Employing the relativistic coupled-cluster method, comparative studies of the parity nonconserving electric dipole amplitudes for the 7 s 1/2 2S →6 d 5/2 2D transitions in 210Fr and 211Fr isotopes have been carried out. It is found that these transition amplitudes, sensitive only to the nuclear spin-dependent effects, are enhanced substantially owing to the very large contributions from the electron core-polarization effects in Fr. This translates to a relatively large and, in principle, measurable induced light shift, which would be a signature of nuclear spin-dependent parity nonconservation that is dominated by the nuclear anapole moment in a heavy atom like Fr. A plausible scheme to measure this quantity using the Cyclotron and Radioisotope Center (CYRIC) facility at Tohoku University has been outlined.

  14. 12 CFR 225.127 - Investment in corporations or projects designed primarily to promote community welfare.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... primarily to promote community welfare. 225.127 Section 225.127 Banks and Banking FEDERAL RESERVE SYSTEM... corporations or projects designed primarily to promote community welfare. (a) Under § 225.25(b)(6) of... equity and debt investments in corporations or projects designed primarily to promote community welfare...

  15. Notionally steady background noise acts primarily as a modulation masker of speech.

    PubMed

    Stone, Michael A; Füllgrabe, Christian; Moore, Brian C J

    2012-07-01

    Stone et al. [J. Acoust. Soc Am. 130, 2874-2881 (2011)], using vocoder processing, showed that the envelope modulations of a notionally steady noise were more effective than the envelope energy as a masker of speech. Here the same effect is demonstrated using non-vocoded signals. Speech was filtered into 28 channels. A masker centered on each channel was added to the channel signal at a target-to-background ratio of -5 or -10 dB. Maskers were sinusoids or noise bands with bandwidth 1/3 or 1 ERB(N) (ERB(N) being the bandwidth of "normal" auditory filters), synthesized with Gaussian (GN) or low-noise (LNN) statistics. To minimize peripheral interactions between maskers, odd-numbered channels were presented to one ear and even to the other. Speech intelligibility was assessed in the presence of each "steady" masker and that masker 100% sinusoidally amplitude modulated (SAM) at 8 Hz. Intelligibility decreased with increasing envelope fluctuation of the maskers. Masking release, the difference in intelligibility between the SAM and its "steady" counterpart, increased with bandwidth from near-zero to around 50 percentage points for the 1-ERB(N) GN. It is concluded that the sinusoidal and GN maskers behaved primarily as energetic and modulation maskers, respectively.

  16. Habitat-specific environmental conditions primarily control the microbiomes of the coral Seriatopora hystrix

    PubMed Central

    Pantos, Olga; Bongaerts, Pim; Dennis, Paul G; Tyson, Gene W; Hoegh-Guldberg, Ove

    2015-01-01

    Reef-building corals form complex relationships with a range of microorganisms including bacteria, archaea, fungi and the unicellular microalgae of the genus Symbiodinium, which together form the coral holobiont. These symbionts are known to have both beneficial and deleterious effects on their coral host, but little is known about what the governing factors of these relationships are, or the interactions that exist between the different members of the holobiont and their environment. Here we used 16S ribosomal RNA gene amplicon sequencing to investigate how archaeal and bacterial communities associated with the widespread scleractinian coral Seriatopora hystrix are influenced by extrinsic (reef habitat and geographic location) and intrinsic (host genotype and Symbiodinium subclade) factors. Bacteria dominate the microbiome of S. hystrix, with members of the Alphaproteobacteria, Gammaproteobacteria and Bacteriodetes being the most predominant in all samples. The richness and evenness of these communities varied between reef habitats, but there was no significant difference between distinct coral host lineages or corals hosting distinct Symbiodinium subclades. The coral microbiomes correlated to reef habitat (depth) and geographic location, with a negative correlation between Alpha- and Gammaproteobacteria, driven by the key members of both groups (Rhodobacteraceae and Hahellaceae, respectively), which showed significant differences between location and depth. This study suggests that the control of microbial communities associated with the scleractinian coral S. hystrix is driven primarily by external environmental conditions rather than by those directly associated with the coral holobiont. PMID:25668159

  17. Habitat-specific environmental conditions primarily control the microbiomes of the coral Seriatopora hystrix.

    PubMed

    Pantos, Olga; Bongaerts, Pim; Dennis, Paul G; Tyson, Gene W; Hoegh-Guldberg, Ove

    2015-09-01

    Reef-building corals form complex relationships with a range of microorganisms including bacteria, archaea, fungi and the unicellular microalgae of the genus Symbiodinium, which together form the coral holobiont. These symbionts are known to have both beneficial and deleterious effects on their coral host, but little is known about what the governing factors of these relationships are, or the interactions that exist between the different members of the holobiont and their environment. Here we used 16S ribosomal RNA gene amplicon sequencing to investigate how archaeal and bacterial communities associated with the widespread scleractinian coral Seriatopora hystrix are influenced by extrinsic (reef habitat and geographic location) and intrinsic (host genotype and Symbiodinium subclade) factors. Bacteria dominate the microbiome of S. hystrix, with members of the Alphaproteobacteria, Gammaproteobacteria and Bacteriodetes being the most predominant in all samples. The richness and evenness of these communities varied between reef habitats, but there was no significant difference between distinct coral host lineages or corals hosting distinct Symbiodinium subclades. The coral microbiomes correlated to reef habitat (depth) and geographic location, with a negative correlation between Alpha- and Gammaproteobacteria, driven by the key members of both groups (Rhodobacteraceae and Hahellaceae, respectively), which showed significant differences between location and depth. This study suggests that the control of microbial communities associated with the scleractinian coral S. hystrix is driven primarily by external environmental conditions rather than by those directly associated with the coral holobiont.

  18. 12 CFR 225.127 - Investment in corporations or projects designed primarily to promote community welfare.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... primarily to promote community welfare. 225.127 Section 225.127 Banks and Banking FEDERAL RESERVE SYSTEM... Investment in corporations or projects designed primarily to promote community welfare. (a) Under § 225.25(b... community welfare, such as the economic rehabilitation and development of low-income areas.” The Board...

  19. African Americans' Perceptions of Their Teaching Experiences in Urban Schools Primarily Consisting of Hispanic Students

    ERIC Educational Resources Information Center

    Jones, Joffery, III.

    2010-01-01

    Purpose: This study examined African American teachers' perceptions of their teaching experiences in schools that were once primarily populated with African American students but have experienced shifts in demographics to primarily consisting of Hispanic students. The study focused on three areas. The first area was African American teachers'…

  20. 12 CFR 225.127 - Investment in corporations or projects designed primarily to promote community welfare.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., small businesses, or nonprofit corporations to help achieve community development. (g) For purposes of... primarily to promote community welfare. 225.127 Section 225.127 Banks and Banking FEDERAL RESERVE SYSTEM... corporations or projects designed primarily to promote community welfare. (a) Under § 225.25(b)(6)...

  1. African Americans' Perceptions of Their Teaching Experiences in Urban Schools Primarily Consisting of Hispanic Students

    ERIC Educational Resources Information Center

    Jones, Joffery, III.

    2010-01-01

    Purpose: This study examined African American teachers' perceptions of their teaching experiences in schools that were once primarily populated with African American students but have experienced shifts in demographics to primarily consisting of Hispanic students. The study focused on three areas. The first area was African American teachers'…

  2. [Study on the inhibit mechanism primarily of extracts from Coptis on clinical resistant the medicine of Staphylococcus aureus].

    PubMed

    Tan, Pin-Xin; Liu, Xiang-Xin; Li, Jun-Chao; He, Jian-Hua

    2011-10-01

    To discuss the inhibit mechanism primarily of extracts from Coptis on clinical resistant the medicine of Staphylococcus aureus. Used SDS-PAGE electrophoresis, spectrophotometry and semiautomatic biochemistry analysis to detect the accumulated concentration of norfloxacin, membranin electrophoretogram and the enzymatic activity in extracellular fluid before and after Coptis extract disposition. The accumulated concentration of medicine norfloxacin within the experiment strains which treated with Coptis extract was clear higher than that of the blank space (P < 0.01); some proteins which molecular weights were in 35 - 38 kDa rebound expressed after Coptis extract treated; The extracellular fluid enzymic activities of resistant Staphylococcus aureus had no significant difference (P > 0.05). The inhibit mechanism primarily of extracts from Coptis on clinical resistant the medicine of Staphylococcus aureus is the results of the combined action of various chemical composition and multi-target interaction, and the exact molecular mechanism remains to be further researched.

  3. Brainstem structures are primarily affected in an experimental model of severe scorpion envenomation.

    PubMed

    Guidine, Patrícia Alves Maia; Cash, Diana; Drumond, Luciana Estefani; de Souza E Rezende, Gustavo Henrique; Massensini, André Ricardo; Williams, Steve Charles Rees; Moraes-Santos, Tasso; Moraes, Márcio Flávio Dutra; Mesquita, Michel Bernanos Soares

    2014-01-01

    Severe scorpion envenoming (SSE) is more frequent in children and is characterized by systemic dysfunctions with a mortality rate of up to 9%. Recent evidence shows that the central nervous system (CNS) plays a key role in triggering the cascade of symptoms present in SSE. The age-dependent role of the CNS in SSE lethality may be summarized in 3 hypotheses: (1) the shown increased blood brain barrier permeability of infants to the toxins would especially and primarily compromise neurovegetative control areas, (2) the neurons within these areas have high affinity to the toxins, and (3) the neurovascular interaction is such that SSE metabolically compromises proper function of toxin-targeted areas. A pharmacological magnetic resonance imaging paradigm was used to evaluate localized hemodynamic changes in relative cerebral blood volume (rCBV) for 30 min after the injection of TsTX, the most lethal toxin from the venom of the Tityus serrulatus scorpion. The brainstem showed significant rCBV reduction 1 min after TsTX administration, whereas rostral brain areas had delayed increase in rCBV (confirmed by laser Doppler measurements of cortical cerebral blood flow). Moreover, metabolic activity by 14C-2-deoxyglucose autoradiography showed the highest relative increase at the brainstem. To test whether TsTX has high affinity to brainstem neurons, the lateral ventricle was injected with Alexa Fluor 568 TsTX. Although some neurons showed intense fluorescence, the labeling pattern suggests that specific neurons were targeted. Altogether, these results suggest that brainstem areas involved in neurovegetative control are most likely within the primary structures triggering the cascade of symptoms present in SSE.

  4. Implementation of Analytical Energy Gradient of Spin-Dependent General Hartree-Fock Method Based on the Infinite-Order Douglas-Kroll-Hess Relativistic Hamiltonian with Local Unitary Transformation.

    PubMed

    Nakajima, Yuya; Seino, Junji; Nakai, Hiromi

    2016-05-10

    An analytical energy gradient for the spin-dependent general Hartree-Fock method based on the infinite-order Douglas-Kroll-Hess (IODKH) method was developed. To treat realistic systems, the local unitary transformation (LUT) scheme was employed both in energy and energy gradient calculations. The present energy gradient method was numerically assessed to investigate the accuracy in several diatomic molecules containing fifth- and sixth-period elements and to examine the efficiency in one-, two-, and three-dimensional silver clusters. To arrive at a practical calculation, we also determined the geometrical parameters of fac-tris(2-phenylpyridine)iridium and investigated the efficiency. The numerical results confirmed that the present method describes a highly accurate relativistic effect with high efficiency. The present method can be a powerful scheme for determining geometries of large molecules, including heavy-element atoms.

  5. A Study of the Basic Speech-Communication Course Designed Primarily for Classroom Teachers.

    ERIC Educational Resources Information Center

    Anderson, Roy Gene

    The purpose of this study was to determine the present status and nature of the basic speech-communication course designed primarily for classroom teachers. Questionnaires were sent to 137 schools that appeared to offer the type of course under study. From the results of the survey, 94 courses were included in the study. Compilation and analysis…

  6. Autism and Developmental Screening in a Public, Primary Care Setting Primarily Serving Hispanics: Challenges and Results

    ERIC Educational Resources Information Center

    Windham, Gayle C.; Smith, Karen S.; Rosen, Nila; Anderson, Meredith C.; Grether, Judith K.; Coolman, Richard B.; Harris, Stephen

    2014-01-01

    We implemented screening of children 16-30 months of age (n = 1,760) from a typically under-served, primarily Hispanic, population, at routine pediatric appointments using the modified checklist for autism in toddlers (M-CHAT) and Ages and Stages Questionnaire. Screen positive rates of 26 and 39%, respectively, were higher than previous reports.…

  7. Examining the Effects of Introducing Online Access to ACS Journals at Primarily Undergraduate Institutions

    ERIC Educational Resources Information Center

    Landolt, R. G.

    2007-01-01

    In collaboration with the Publications Division of the American Chemical Society (ACS), students and faculty at 24 primarily undergraduate institutions were provided online access to ACS primary research journals for a period of 18 months, and a group of eight schools were granted access to use the archives of ACS journals for a year. Resources…

  8. 12 CFR 225.127 - Investment in corporations or projects designed primarily to promote community welfare.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... social problems. Although the interpretation primarily focuses on low- and moderate-income housing, it is... social ills. Section 225.25(b)(6) is intended to provide an opportunity for them to assume such a role... groups (for example, minority equity investments, on a temporary basis, in small or medium-sized locally...

  9. 12 CFR 225.127 - Investment in corporations or projects designed primarily to promote community welfare.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Nation's social problems. Although the interpretation primarily focuses on low- and moderate-income... remedying our social ills. Section 225.25(b)(6) is intended to provide an opportunity for them to assume... or medium-sized locally-controlled businesses in low-income urban or other economically depressed...

  10. Examining the Effects of Introducing Online Access to ACS Journals at Primarily Undergraduate Institutions

    ERIC Educational Resources Information Center

    Landolt, R. G.

    2007-01-01

    In collaboration with the Publications Division of the American Chemical Society (ACS), students and faculty at 24 primarily undergraduate institutions were provided online access to ACS primary research journals for a period of 18 months, and a group of eight schools were granted access to use the archives of ACS journals for a year. Resources…

  11. Identity-Related Influences on the Success of Minority Workers in Primarily Nonminority Organizations.

    ERIC Educational Resources Information Center

    James, Keith; Khoo, Gillian

    1991-01-01

    Reviews literature at the micro- (individual, interpersonal, and small group) and macro- (organizational, societal, and cultural) levels relating to the experiences and outcomes of minorities in work settings populated primarily by members of the majority. Uses Tajfel and Turner's Social Identity Theory as an organizational and integrative…

  12. Propulsion and control propellers with thruster nozzles primarily for aircraft applications

    NASA Technical Reports Server (NTRS)

    Pabst, W.

    1986-01-01

    A propulsion and control propeller with thruster nozzles, primarily for aircraft application is described. Adjustability of rotor blades at the hub and pressurized gas expulsion combined with an air propeller increase power. Both characteristics are combined in one simple device, and, furthermore, incorporate overall aircraft control so that mechanisms which govern lateral and horizontal movement become superfluous.

  13. 29 CFR 780.607 - “Primarily employed” in agriculture.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false âPrimarily employedâ in agriculture. 780.607 Section 780... AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT Employment in Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption...

  14. 29 CFR 780.607 - “Primarily employed” in agriculture.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false âPrimarily employedâ in agriculture. 780.607 Section 780... AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT Employment in Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption...

  15. 29 CFR 780.607 - “Primarily employed” in agriculture.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false âPrimarily employedâ in agriculture. 780.607 Section 780... AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT Employment in Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption...

  16. 29 CFR 780.607 - “Primarily employed” in agriculture.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false âPrimarily employedâ in agriculture. 780.607 Section 780... AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT Employment in Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption...

  17. 29 CFR 780.607 - “Primarily employed” in agriculture.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false âPrimarily employedâ in agriculture. 780.607 Section 780... AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT Employment in Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption...

  18. Autism and Developmental Screening in a Public, Primary Care Setting Primarily Serving Hispanics: Challenges and Results

    ERIC Educational Resources Information Center

    Windham, Gayle C.; Smith, Karen S.; Rosen, Nila; Anderson, Meredith C.; Grether, Judith K.; Coolman, Richard B.; Harris, Stephen

    2014-01-01

    We implemented screening of children 16-30 months of age (n = 1,760) from a typically under-served, primarily Hispanic, population, at routine pediatric appointments using the modified checklist for autism in toddlers (M-CHAT) and Ages and Stages Questionnaire. Screen positive rates of 26 and 39%, respectively, were higher than previous reports.…

  19. 12 CFR 208.7 - Prohibition against use of interstate branches primarily for deposit production.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... primarily for deposit production. 208.7 Section 208.7 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM MEMBERSHIP OF STATE BANKING INSTITUTIONS IN THE FEDERAL RESERVE SYSTEM (REGULATION H) General Membership and Branching Requirements § 208.7 Prohibition against use of...

  20. Primarily chronic progressive and relapsing/remitting multiple sclerosis: two immunogenetically distinct disease entities.

    PubMed Central

    Olerup, O; Hillert, J; Fredrikson, S; Olsson, T; Kam-Hansen, S; Möller, E; Carlsson, B; Wallin, J

    1989-01-01

    HLA class II gene polymorphism was investigated in 100 patients with clinically definite multiple sclerosis (MS) by restriction fragment length polymorphism analysis of Taq I-digested DNA using DRB, DQA, and DQB cDNA probes. Twenty-six patients had primarily chronic progressive MS and 74 had relapsing/remitting MS. The latter group included patients with a secondary progressive evolution of symptoms. Both clinical forms of MS were found to be associated with the DRw15,DQw6 haplotype. In addition, primarily chronic progressive MS was positively associated with the DQB1 restriction fragment pattern seen in DR4,DQw8, DR7,DQw9, and DRw8, DQw4 haplotypes, as well as negatively associated with the Taq I DQB1 allelic pattern corresponding to the serological specificity DQw7. Relapsing/remitting MS was positively associated with the DQB1 allelic pattern observed in the DRw17,DQw2 haplotype. These three DQB1 alleles are in strong negative linkage disequilibria with DRw15. The two susceptibility markers of each clinical form of MS act additively in determining the genetic susceptibility, as the relative risks for individuals carrying both markers roughly equal the sum of respective risks. Different alleles of the DQB1 locus defined by restriction fragment length polymorphisms contribute to susceptibility and resistance to primarily chronic progressive MS as well as to susceptibility to relapsing/remitting MS. The observed immunogenetic heterogeneity between the different clinical forms of MS favors the hypothesis that primarily chronic progressive MS and relapsing/remitting MS are two distinct disease entities. Images PMID:2571150

  1. Pharmacometric Approaches to Personalize Use of Primarily Renally Eliminated Antibiotics in Preterm and Term Neonates.

    PubMed

    Wilbaux, Mélanie; Fuchs, Aline; Samardzic, Janko; Rodieux, Frédérique; Csajka, Chantal; Allegaert, Karel; van den Anker, Johannes N; Pfister, Marc

    2016-08-01

    Sepsis remains a major cause of mortality and morbidity in neonates, and, as a consequence, antibiotics are the most frequently prescribed drugs in this vulnerable patient population. Growth and dynamic maturation processes during the first weeks of life result in large inter- and intrasubject variability in the pharmacokinetics (PK) and pharmacodynamics (PD) of antibiotics. In this review we (1) summarize the available population PK data and models for primarily renally eliminated antibiotics, (2) discuss quantitative approaches to account for effects of growth and maturation processes on drug exposure and response, (3) evaluate current dose recommendations, and (4) identify opportunities to further optimize and personalize dosing strategies of these antibiotics in preterm and term neonates. Although population PK models have been developed for several of these drugs, exposure-response relationships of primarily renally eliminated antibiotics in these fragile infants are not well understood, monitoring strategies remain inconsistent, and consensus on optimal, personalized dosing of these drugs in these patients is absent. Tailored PK/PD studies and models are useful to better understand relationships between drug exposures and microbiological or clinical outcomes. Pharmacometric modeling and simulation approaches facilitate quantitative evaluation and optimization of treatment strategies. National and international collaborations and platforms are essential to standardize and harmonize not only studies and models but also monitoring and dosing strategies. Simple bedside decision tools assist clinical pharmacologists and neonatologists in their efforts to fine-tune and personalize the use of primarily renally eliminated antibiotics in term and preterm neonates. © 2016, The American College of Clinical Pharmacology.

  2. Environmental changes affect the assembly of soil bacterial community primarily by mediating stochastic processes.

    PubMed

    Zhang, Ximei; Johnston, Eric R; Liu, Wei; Li, Linghao; Han, Xingguo

    2016-01-01

    Both 'species fitness difference'-based deterministic processes, such as competitive exclusion and environmental filtering, and 'species fitness difference'-independent stochastic processes, such as birth/death and dispersal/colonization, can influence the assembly of soil microbial communities. However, how both types of processes are mediated by anthropogenic environmental changes has rarely been explored. Here we report a novel and general pattern that almost all anthropogenic environmental changes that took place in a grassland ecosystem affected soil bacterial community assembly primarily through promoting or restraining stochastic processes. We performed four experiments mimicking 16 types of environmental changes and separated the compositional variation of soil bacterial communities caused by each environmental change into deterministic and stochastic components, with a recently developed method. Briefly, because the difference between control and treatment communities is primarily caused by deterministic processes, the deterministic change was quantified as (mean compositional variation between treatment and control) - (mean compositional variation within control). The difference among replicate treatment communities is primarily caused by stochastic processes, so the stochastic change was estimated as (mean compositional variation within treatment) - (mean compositional variation within control). The absolute of the stochastic change was greater than that of the deterministic change across almost all environmental changes, which was robust for both taxonomic and functional-based criterion. Although the deterministic change may become more important as environmental changes last longer, our findings showed that changes usually occurred through mediating stochastic processes over 5 years, challenging the traditional determinism-dominated view.

  3. Three body interaction effects on the phase diagram of spinor bosons

    NASA Astrophysics Data System (ADS)

    Nabi, Sk Noor; Basu, Saurabh

    2016-10-01

    We include a three body density interaction in the Bose Hubbard model and study its effects on the phase diagram for spinor (S = 1) bosons on an optical lattice via a mean field theory. The Mott insulating (MI) phases are noted to stabilize, in the sense that the MI phases extend to larger values of the system parameters alongwith widening of the particle-hole excitation spectrum as the three body interaction term is included for both the polar (spin dependent interaction being positive) and the ferromagnetic (spin dependent interaction being negative) cases. Another remarkable feature emerges as the phase diagram corresponding to the ferromagnetic case becomes distinct from that of its spinless variant, which in the absence of the three body term is indistinguishable from that of the scalar particles. A strong coupling perturbation theory is employed to provide analytical support to the above results.

  4. Effect of electron trap states on spin-dependent transport characteristics in CoFe/MgO/n{sup +}-Si junctions investigated by Hanle effect measurements and inelastic electron tunneling spectroscopy

    SciTech Connect

    Inokuchi, Tomoaki Ishikawa, Mizue; Sugiyama, Hideyuki; Tanamoto, Tetsufumi; Saito, Yoshiaki

    2014-12-08

    Spin-dependent transport properties in CoFe/MgO/n{sup +}-Si junctions were investigated by Hanle effect measurements and inelastic electron tunneling (IET) spectroscopy. The CoFe/MgO/n{sup +}-Si junctions examined in this study exhibited two different Hanle curves. In the low bias region, broad Hanle signals were mainly observed; in the high bias region, narrow Hanle signals were mainly observed. The d{sup 2}I/dV{sup 2}-V curves (which correspond to IET spectra) contain several peaks originating from phonon modes and other peaks originating from electron trap states. At the bias voltage where electron trap states are observed, Δd{sup 2}I/dV{sup 2} depends on the magnetic field and the full width at half-maximum of the Δd{sup 2}I/dV{sup 2}–H curves corresponds to that of the broad Hanle signals. These results indicate that electron trap states are located in the low energy region and cause a decrease in spin lifetime.

  5. Measurement of the spin-dependent parameter D, R, A, and P, and analyzing power for vector p-d elastic scattering at 500 and 800 MeV

    SciTech Connect

    Rahbar, A.A.

    1982-09-01

    A specific set of spin dependent parameters for elastic scattering of polarized protons from an unpolarized deuterium target have been measured over the angular range of 15/sup 0/ and 65/sup 0/ in the Laboratory system. The experiment was performed at the Los Alamos Meson Physics Facility (LAMPF) using a polarized proton beam of 0.5 and 0.8 GeV incident kinetic energy. A carbon analyzer was used to measure the scattered proton polarization. This comprises the first set of measurements in the intermediate energy range. Of particular interest, the analyzing power, (A/sub y/), has been measured for the pd elastic scattering reaction at both energies. A test of Time-Reversal Invariance (TRI) has been made for this reaction. This was accomplished by comparing the polarization (P) with the analyzing power A/sub y/ together with the depolarization parameter, (D), which was measured in this experiment. No evidence of time-reversal violation was found for this reaction in the region of non-zero spin flip probability. The measurements also furnished very useful and selective information on the p-d collision matrix, as well as the double-spin-flip nucleon-nucleon amplitudes.

  6. Current-perpendicular-to-the-plane magnetoresistance from large interfacial spin-dependent scattering between Co50Fe50 magnetic layer and In-Zn-O conductive oxide spacer layer

    NASA Astrophysics Data System (ADS)

    Nakatani, T. M.; Childress, J. R.

    2015-06-01

    We have investigated electrically conductive indium-zinc-oxide (IZO) deposited by magnetron sputtering as spacer layer for current-perpendicular-to-the-plane giant magnetoresistance sensor devices. Spin-valves with a Co50Fe50/IZO/Co50Fe50 trilayer showed resistance-area product (RA) ranging from 110 to 250 mΩ μm2, significantly larger than all-metal structures with Ag or Cu spacers (˜40 mΩ μm2). Magnetoresistance ratios (ΔR/R) of 2.5% to 5.5% depending on the IZO spacer thickness (1.5-6.0 nm), corresponding to ΔRA values from 3 to 13 mΩ μm2, were obtained. The values of ΔRA with the IZO spacers and Co50Fe50 magnetic layers were significantly larger than those with conventional metal spacers and Co50Fe50 magnetic layers (˜1-2 mΩ μm2). The dependence of ΔRA on the magnetic layer thickness suggests that the larger ΔRA obtained with IZO spacer is due to a large interfacial spin-dependent scattering caused by the large specific resistance at the Co50Fe50/IZO interface. From structural characterization by TEM and the observed dependence of the RA dispersion on device size, the electric current flowing through the IZO spacer is thought to be laterally uniform, similar to normal metal spacers.

  7. Spin-dependent and photon-assisted transmission enhancement and suppression in a magnetic-field tunable ZnSe/Zn{sub 1–x}Mn{sub x}Se heterostructure

    SciTech Connect

    Li, Chun-Lei; Yuan, Rui-Yang; Guo, Yong

    2016-01-07

    Using the effective-mass approximation and Floquet theory, we theoretically investigate the terahertz photon-assisted transport through a ZnSe/Zn{sub 1−x}Mn{sub x}Se heterostructure under an external magnetic field, an electric field, and a spatially homogeneous oscillatory field. The results show that both amplitude and frequency of the oscillatory field can accurately manipulate the magnitude of the spin-dependent transmission probability and the positions of the Fano-type resonance due to photon absorption and emission processes. Transmission resonances can be enhanced to optimal resonances or drastically suppressed for spin-down electrons tunneling through the heterostructure and for spin-up ones tunneling through the same structure, resonances can also be enhanced or suppressed, but the intensity is less than the spin-down ones. Furthermore, it is important to note that transmission suppression can be clearly seen from both the spin-down component and the spin-up component of the current density at low magnetic field; at the larger magnetic field, however, the spin-down component is suppressed, and the spin-up component is enhanced. These interesting properties may provide an alternative method to develop multi-parameter modulation electron-polarized devices.

  8. Regeneration of Cone Photoreceptors when Cell Ablation Is Primarily Restricted to a Particular Cone Subtype

    PubMed Central

    Fraser, Brittany; DuVal, Michèle G.; Wang, Hao; Allison, W. Ted

    2013-01-01

    We sought to characterize the regenerated cells, if any, when photoreceptor ablation was mostly limited to a particular cone subtype. This allowed us to uniquely assess whether the remaining cells influence specification of regenerating photoreceptors. The ability to replace lost photoreceptors via stem cell therapy holds promise for treating many retinal degenerative diseases. Zebrafish are potent for modelling this because they have robust regenerative capacity emanating from endogenous stem cells, and abundant cone photoreceptors including multiple spectral subtypes similar to human fovea. We ablated the homolog of the human S-cones, the ultraviolet-sensitive (UV) cones, and tested the hypothesis that the photoreceptors regenerating in their place take on identities matching those expected from normal cone mosaic development. We created transgenic fish wherein UV cones can be ablated by addition of a prodrug. Thus photoreceptors developed normally and only the UV cones expressed nitroreductase; the latter converts the prodrug metronidazole to a cell-autonomous neurotoxin. A significant increase in proliferation of progenitor cell populations (p<0.01) was observed when cell ablation was primarily limited to UV cones. In control fish, we found that BrdU primarily incorporated into rod photoreceptors, as expected. However the majority of regenerating photoreceptors became cones when retinal cell ablation was predominantly restricted to UV cones: a 2-fold increase in the relative abundance of cones (p = 0.008) was mirrored by a 35% decrease in rods. By primarily ablating only a single photoreceptor type, we show that the subsequent regeneration is biased towards restoring the cognate photoreceptor type. We discuss the hypothesis that, after cone death, the microenvironment formed by the remaining retinal cells may be influential in determining the identity of regenerating photoreceptors, though other interpretations are plausible. Our novel animal model provides

  9. Magnetodielectric Response from Spin-Orbital Interaction Occurring at Interface of Ferromagnetic Co and Organometal Halide Perovskite Layers via Rashba Effect.

    PubMed

    Li, Mingxing; Li, Ling; Mukherjee, Rupam; Wang, Kai; Liu, Qing; Zou, Qiang; Xu, Hengxing; Tisdale, Jeremy; Gai, Zheng; Ivanov, Ilia N; Mandrus, David; Hu, Bin

    2017-02-01

    The spin on a ferromagnetic Co surface can interact with the asymmetric orbital on an organometal halide perovskite surface, leading to an anisotropic magnetodielectric effect. This study presents an opportunity to integrate ferromagnetic and semiconducting properties through the Rasbha effect for achieving spin-dependent electronic functionalities based on thin-film design.

  10. 49 CFR 37.107 - Acquisition of passenger rail cars by private entities primarily engaged in the business of...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... entities primarily engaged in the business of transporting people. 37.107 Section 37.107 Transportation... entities primarily engaged in the business of transporting people. (a) A private entity which is primarily engaged in the business of transporting people and whose operations affect commerce, which makes...

  11. 49 CFR 37.171 - Equivalency requirement for demand responsive service operated by private entities not primarily...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... service operated by private entities not primarily engaged in the business of transporting people. 37.171... responsive service operated by private entities not primarily engaged in the business of transporting people. A private entity not primarily engaged in the business of transporting people which operates a...

  12. 49 CFR 37.171 - Equivalency requirement for demand responsive service operated by private entities not primarily...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... service operated by private entities not primarily engaged in the business of transporting people. 37.171... responsive service operated by private entities not primarily engaged in the business of transporting people. A private entity not primarily engaged in the business of transporting people which operates a...

  13. 49 CFR 37.107 - Acquisition of passenger rail cars by private entities primarily engaged in the business of...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... entities primarily engaged in the business of transporting people. 37.107 Section 37.107 Transportation... entities primarily engaged in the business of transporting people. (a) A private entity which is primarily engaged in the business of transporting people and whose operations affect commerce, which makes a...

  14. 49 CFR 37.171 - Equivalency requirement for demand responsive service operated by private entities not primarily...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... service operated by private entities not primarily engaged in the business of transporting people. 37.171... responsive service operated by private entities not primarily engaged in the business of transporting people. A private entity not primarily engaged in the business of transporting people which operates a...

  15. 49 CFR 37.171 - Equivalency requirement for demand responsive service operated by private entities not primarily...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... service operated by private entities not primarily engaged in the business of transporting people. 37.171... responsive service operated by private entities not primarily engaged in the business of transporting people. A private entity not primarily engaged in the business of transporting people which operates a...

  16. 49 CFR 37.171 - Equivalency requirement for demand responsive service operated by private entities not primarily...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... service operated by private entities not primarily engaged in the business of transporting people. 37.171... responsive service operated by private entities not primarily engaged in the business of transporting people. A private entity not primarily engaged in the business of transporting people which operates a...

  17. 49 CFR 37.107 - Acquisition of passenger rail cars by private entities primarily engaged in the business of...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... entities primarily engaged in the business of transporting people. 37.107 Section 37.107 Transportation... entities primarily engaged in the business of transporting people. (a) A private entity which is primarily engaged in the business of transporting people and whose operations affect commerce, which makes a...

  18. Spin-Dependent Phenomena in Graphene

    DTIC Science & Technology

    2012-03-15

    observed the spin lifetimes as high at 771 ps in single-layer graphene (SLG), 1.0 ns at 4 K in SLG, and 6.2 ns at 20 K in bilayer graphene ( BLG ) [9...lifetime are observed between SLG and BLG , which suggest different mechanisms for spin relaxation in SLG and BLG [9]. (2) Spin and Charge...bilayer graphene ( BLG ) [9]. At low temperatures, we found that the spin lifetimes in BLG were typically longer than SLG. The longest reported value for

  19. Decisive data sets in phylogenomics: lessons from studies on the phylogenetic relationships of primarily wingless insects.

    PubMed

    Dell'Ampio, Emiliano; Meusemann, Karen; Szucsich, Nikolaus U; Peters, Ralph S; Meyer, Benjamin; Borner, Janus; Petersen, Malte; Aberer, Andre J; Stamatakis, Alexandros; Walzl, Manfred G; Minh, Bui Quang; von Haeseler, Arndt; Ebersberger, Ingo; Pass, Günther; Misof, Bernhard

    2014-01-01

    Phylogenetic relationships of the primarily wingless insects are still considered unresolved. Even the most comprehensive phylogenomic studies that addressed this question did not yield congruent results. To get a grip on these problems, we here analyzed the sources of incongruence in these phylogenomic studies by using an extended transcriptome data set. Our analyses showed that unevenly distributed missing data can be severely misleading by inflating node support despite the absence of phylogenetic signal. In consequence, only decisive data sets should be used which exclusively comprise data blocks containing all taxa whose relationships are addressed. Additionally, we used Four-cluster Likelihood Mapping (FcLM) to measure the degree of congruence among genes of a data set, as a measure of support alternative to bootstrap. FcLM showed incongruent signal among genes, which in our case is correlated neither with functional class assignment of these genes nor with model misspecification due to unpartitioned analyses. The herein analyzed data set is the currently largest data set covering primarily wingless insects, but failed to elucidate their interordinal phylogenetic relationships. Although this is unsatisfying from a phylogenetic perspective, we try to show that the analyses of structure and signal within phylogenomic data can protect us from biased phylogenetic inferences due to analytical artifacts.

  20. Decisive Data Sets in Phylogenomics: Lessons from Studies on the Phylogenetic Relationships of Primarily Wingless Insects

    PubMed Central

    Meusemann, Karen; Meyer, Benjamin; Borner, Janus; Petersen, Malte; Aberer, Andre J.; Stamatakis, Alexandros; Walzl, Manfred G.; Minh, Bui Quang; von Haeseler, Arndt; Ebersberger, Ingo; Pass, Günther; Misof, Bernhard

    2014-01-01

    Phylogenetic relationships of the primarily wingless insects are still considered unresolved. Even the most comprehensive phylogenomic studies that addressed this question did not yield congruent results. To get a grip on these problems, we here analyzed the sources of incongruence in these phylogenomic studies by using an extended transcriptome data set. Our analyses showed that unevenly distributed missing data can be severely misleading by inflating node support despite the absence of phylogenetic signal. In consequence, only decisive data sets should be used which exclusively comprise data blocks containing all taxa whose relationships are addressed. Additionally, we used Four-cluster Likelihood Mapping (FcLM) to measure the degree of congruence among genes of a data set, as a measure of support alternative to bootstrap. FcLM showed incongruent signal among genes, which in our case is correlated neither with functional class assignment of these genes nor with model misspecification due to unpartitioned analyses. The herein analyzed data set is the currently largest data set covering primarily wingless insects, but failed to elucidate their interordinal phylogenetic relationships. Although this is unsatisfying from a phylogenetic perspective, we try to show that the analyses of structure and signal within phylogenomic data can protect us from biased phylogenetic inferences due to analytical artifacts. PMID:24140757

  1. Impact of medication therapy management on underserved, primarily Hispanic patients with diabetes.

    PubMed

    Congdon, Heather B; Dowling, Thomas C; Cheng, Iliana; Truong, Hoai-An

    2013-05-01

    Diabetes-related complications are more pronounced in Hispanic patients versus patients of other ethnicities. It is documented that medication therapy management (MTM) can improve diabetes outcomes; however, data regarding Hispanic patients are limited. To evaluate the impact of MTM on hemoglobin A1c (A1C), blood pressure (BP), and low-density lipoprotein cholesterol (LDL-C) in underserved, primarily Hispanic patients who use a safety-net clinic as their medical home. A retrospective, observational study of uninsured, primarily Hispanic patients with diabetes who received MTM from October 2009 through March 2011. Patients were stratified into 2 cohorts: A1C less than 9% and A1C greater than or equal to 9%. Patients were also stratified by frequency of MTM visits and insulin use, regardless of A1C. A chart review was conducted to evaluate diabetes-related outcomes pre- and postimplementation of MTM. The primary study outcome was reduction of A1C. Secondary outcomes included reduction of BP and LDL-C and reduction of A1C based on MTM visit frequency or insulin use. Sixty-four patients with at least 1 MTM visit and pre- and postimplementation A1C data were included. In the cohort with A1C greater than or equal to 9%, mean (SD) A1C values decreased from 10.9% (1.4%) to 8.8% (1.5%) versus the cohort with A1C less than 9%, whose A1C changed minimally, from 7.2% (0.9%) to 7.4% (1.4%). Regardless of their A1C, patients who were using insulin at baseline had a change in A1C of -0.8% (1.5%) versus -0.1% (1.6%) in those who were not using insulin at baseline (p = 0.04); patients who participated in multiple MTM visits had a significant reduction in A1C, from 9% to 8.3% (95% CI -1.26 to -0.03; p = 0.02) compared with patients participating in only 1 MTM visit. Pharmacist-provided MTM can significantly improve diabetes control in uninsured, primarily Hispanic patients with poorly controlled diabetes and in those who are using insulin. Multiple MTM visits also yielded

  2. Mott lobes of the S =1 Bose-Hubbard model with three-body interactions

    NASA Astrophysics Data System (ADS)

    Hincapie-F, A. F.; Franco, R.; Silva-Valencia, J.

    2016-09-01

    Using the density-matrix renormalization-group method, we studied the ground state of the one-dimensional S =1 Bose-Hubbard model with local three-body interactions, which can be a superfluid or a Mott insulator state. We drew the phase diagram of this model for both ferromagnetic and antiferromagnetic interaction. Regardless of the sign of the spin-dependent coupling, we obtained that the Mott lobes area decreases as the spin-dependent strength increases, which means that the even-odd asymmetry of the two-body antiferromagnetic chain is absent for local three-body interactions. For antiferromagnetic coupling, we found that the density drives first-order superfluid-Mott insulator transitions for even and odd lobes. Ferromagnetic Mott insulator and superfluid states were obtained with a ferromagnetic coupling, and a tendency to a "long-range" order was observed.

  3. Autism and developmental screening in a public, primary care setting primarily serving Hispanics: challenges and results.

    PubMed

    Windham, Gayle C; Smith, Karen S; Rosen, Nila; Anderson, Meredith C; Grether, Judith K; Coolman, Richard B; Harris, Stephen

    2014-07-01

    We implemented screening of children 16-30 months of age (n = 1,760) from a typically under-served, primarily Hispanic, population, at routine pediatric appointments using the modified checklist for autism in toddlers (M-CHAT) and Ages and Stages Questionnaire. Screen positive rates of 26 and 39%, respectively, were higher than previous reports. Hispanics were more likely to score M-CHAT positive than non-Hispanics (adjusted OR 1.7, 95% CI 1.2-2.4), as were those screened in Spanish. About 30% of screen-positive children were referred for further assessment, but only half were seen. Thus screening in this population is feasible, but may require additional resources. Attention to the cultural applicability of screening instruments, as well as to explaining the results or need for additional services to parents, is critical to serve the growing Hispanic population.

  4. Primarily chronic and cerebrovascular course of Lyme neuroborreliosis: case reports and literature review

    PubMed Central

    Wilke, M.; Eiffert, H.; Christen, H.; Hanefeld, F.

    2000-01-01

    As part of an ongoing study aiming to define the clinical spectrum of neuroborreliosis in childhood, we have identified four patients with unusual clinical manifestations. Two patients suffered from a primarily chronic form of neuroborreliosis and displayed only non-specific symptoms. An 11 year old boy presented with long standing symptoms of severe weight loss and chronic headache, while the other patient had pre-existing mental and motor retardation and developed seizures and failure to thrive. Two further children who presented with acute hemiparesis as a result of cerebral ischaemic infarction had a cerebrovascular course of neuroborreliosis. One was a 15 year old girl; the other, a 5 year old boy, is to our knowledge the youngest patient described with this course of illness. Following adequate antibiotic treatment, all patients showed substantial improvement of their respective symptoms. Laboratory and magnetic resonance imaging findings as well as clinical course are discussed and the relevant literature is reviewed.

 PMID:10869004

  5. Direct healthcare costs of selected diseases primarily or partially transmitted by water

    PubMed Central

    COLLIER, S. A.; STOCKMAN, L. J.; HICKS, L. A.; GARRISON, L. E.; ZHOU, F. J.; BEACH, M. J.

    2015-01-01

    SUMMARY Despite US sanitation advancements, millions of waterborne disease cases occur annually, although the precise burden of disease is not well quantified. Estimating the direct healthcare cost of specific infections would be useful in prioritizing waterborne disease prevention activities. Hospitalization and outpatient visit costs per case and total US hospitalization costs for ten waterborne diseases were calculated using large healthcare claims and hospital discharge databases. The five primarily waterborne diseases in this analysis (giardiasis, cryptosporidiosis, Legionnaires’ disease, otitis externa, and non-tuberculous mycobacterial infection) were responsible for over 40 000 hospitalizations at a cost of $970 million per year, including at least $430 million in hospitalization costs for Medicaid and Medicare patients. An additional 50 000 hospitalizations for campylobacteriosis, salmonellosis, shigellosis, haemolytic uraemic syndrome, and toxoplasmosis cost $860 million annually ($390 million in payments for Medicaid and Medicare patients), a portion of which can be assumed to be due to waterborne transmission. PMID:22233584

  6. N170 Changes Show Identifiable Chinese Characters Compete Primarily with Faces Rather than Houses.

    PubMed

    Fan, Cong; He, Weiqi; He, Huamin; Ren, Guofang; Luo, Yuejia; Li, Hong; Luo, Wenbo

    2015-01-01

    Character processing is a crucial cognitive skill that is highly emphasized and industriously cultivated in contemporary society. In the present study, using a competition paradigm, we examined the electrophysiological correlates of different relationships between Chinese characters and faces and between Chinese characters and houses during early visual processing. We observed that identifiable Chinese characters compete primarily with faces rather than houses at an early visual processing stage, with a significantly reduced N170 for faces but not for houses, when they were viewed concurrently with identifiable characters relative to when they were viewed concurrently with unidentifiable characters. Consistent with our previous study, there was a significant increase in N170 after characters have been learned, indicating a modulatory effect of Chinese character identification level on N170 amplitude. Furthermore, we found an enlarged N170 in response to faces compared to houses, indicating that the neural mechanisms for processing faces and houses are different at an early visual processing stage.

  7. Characterization of the type of calcium channel primarily regulating GABA exocytosis from brain nerve endings.

    PubMed

    Sitges, M; Chiu, L M

    1995-09-01

    In an attempt to further characterize the type of Ca2+ channels primarily regulating GABA exocytosis, the effects of increasing concentrations of omega CTx MVIIC,-omega-Aga IVA and other Ca2+ channel blockers (nitrendipine, Cd2+ and Ni2+), commonly used for pharmacologically discerning among the various types of Ca2+ channels, were tested on the dissected Ca2+ dependent fraction of the depolarization evoked release of GABA from mouse brain synaptosomes. Our results show that omega-CTx MVIIC inhibits GABA exocytosis with a calculated IC50 of 3 microM and omega-Aga IVA with a calculated IC50 of 50 nM. The divalent cation Cd2+ only diminishes GABA exocytosis at 70 microM, but does not modify this response at lower concentrations (i.e. 1 and 10 microM). Neither nitrendipine (10 microM) nor Ni2+ (100 microM and 500 microM) modified GABA exocytosis. The failure of nitrendipine at a high concentration to inhibit GABA exocytosis discards L-type Ca2+ channels as the main regulators of this response; likewise that of Ni2+ discards Ca2+ channels of the N-type, and the failure of nM concentrations of omega-CTx MVIIC or 500 microM Ni2+, also discards alpha 1A/Q-type Ca2+ channels as the main regulators of the GABA response. On the basis of these results and in particular of the higher potency of omega-Aga IVA than omega-CTx MVIIC, it is concluded that the type of Ca2+ channels that primarily determine the exocytosis of GABA belong to a P-like type of Ca2+ channels.

  8. Current-perpendicular-to-the-plane magnetoresistance from large interfacial spin-dependent scattering between Co{sub 50}Fe{sub 50} magnetic layer and In-Zn-O conductive oxide spacer layer

    SciTech Connect

    Nakatani, T. M. Childress, J. R.

    2015-06-28

    We have investigated electrically conductive indium-zinc-oxide (IZO) deposited by magnetron sputtering as spacer layer for current-perpendicular-to-the-plane giant magnetoresistance sensor devices. Spin-valves with a Co{sub 50}Fe{sub 50}/IZO/Co{sub 50}Fe{sub 50} trilayer showed resistance-area product (RA) ranging from 110 to 250 mΩ μm{sup 2}, significantly larger than all-metal structures with Ag or Cu spacers (∼40 mΩ μm{sup 2}). Magnetoresistance ratios (ΔR/R) of 2.5% to 5.5% depending on the IZO spacer thickness (1.5–6.0 nm), corresponding to ΔRA values from 3 to 13 mΩ μm{sup 2}, were obtained. The values of ΔRA with the IZO spacers and Co{sub 50}Fe{sub 50} magnetic layers were significantly larger than those with conventional metal spacers and Co{sub 50}Fe{sub 50} magnetic layers (∼1–2 mΩ μm{sup 2}). The dependence of ΔRA on the magnetic layer thickness suggests that the larger ΔRA obtained with IZO spacer is due to a large interfacial spin-dependent scattering caused by the large specific resistance at the Co{sub 50}Fe{sub 50}/IZO interface. From structural characterization by TEM and the observed dependence of the RA dispersion on device size, the electric current flowing through the IZO spacer is thought to be laterally uniform, similar to normal metal spacers.

  9. The development and characterization of a primarily mineral calcium phosphate - poly(epsilon-caprolactone) biocomposite

    NASA Astrophysics Data System (ADS)

    Dunkley, Ian Robert

    Orthopaedic reconstruction often involves the surgical introduction of structural implants that provide for rigid fixation, skeletal stabilization, and bone integration. The high stresses incurred by these implanted devices have historically limited material choices to metallic and select polymeric formulations. While mechanical requirements are achieved, these non-degradable materials do not participate actively in the remodeling of the skeleton and present the possibility of long-term failure or rejection. This is particularly relevant in cervical fusion, an orthopaedic procedure to treat damaged, degenerative or diseased intervertebral discs. A significant improvement on the available synthetic bone replacement/regeneration options for implants to treat these conditions in the cervical spine may be achieved with the development of primarily mineral biocomposites comprised of a bioactive ceramic matrix reinforced with a biodegradable polymer. Such a biocomposite may be engineered to possess the clinically required mechanical properties of a particular application, while maintaining the ability to be remodeled completely by the body. A biocomposite of Si-doped calcium phosphate (Si-CaP) and poly(epsilon-caprolactone) (PCL) was developed for application as such a synthetic bone material for potential use as a fusion device in the cervical spine. In this thesis, a method by which high mineral content Si-CaP/PCL biocomposites with interpenetrating matrices of mineral and polymer phases may be prepared will be demonstrated, in addition to the effects of the various preparation parameters on the biocomposite density, porosity and mechanical properties. This new technique by which dense, primarily ceramic Si-CaP/PCL biocomposites were prepared, allowed for the incorporation of mineral contents ranging between 45-97vol%. Polymer infiltration, accomplished solely by passive capillary uptake over several days, was found to be capable of fully infiltrating the microporosity

  10. River drainage patterns in the New Zealand Alps primarily controlled by plate tectonic strain

    NASA Astrophysics Data System (ADS)

    Castelltort, Sébastien; Goren, Liran; Willett, Sean D.; Champagnac, Jean-Daniel; Herman, Frédéric; Braun, Jean

    2012-10-01

    River drainage patterns sculpt terrestrial landscapes. Whether these patterns contain fingerprints of past tectonic events is debated. On the one hand, elaborate dendritic river networks always retain an invariant structure, implying that rivers will simply reorganize in response to tectonic perturbations, without long-term trace of the tectonic event. On the other hand, many rivers in active mountain belts seem to be passive features and may record long-term crustal deformation. Here we use numerical simulations, constrained by drainage patterns observed in the Southern Alps of New Zealand, to analyse the response of river basins to distributed plate tectonic strain. We find that both dynamically reorganized and passively deformed rivers coexist in the Southern Alps. Rivers on the western side of the mountain range reorganize and rapidly evolve in response to tectonic deformation. In contrast, rivers on the eastern side resist reorganization and record large-scale plate tectonic influence over timescales of tens of millions of years. We conclude that both types of river drainage pattern in the Southern Alps are primarily controlled by plate tectonic strain, implying that landscape topography can be used to reconstruct the distribution of tectonic strain within zones of continental deformation around the world.

  11. Dehaloperoxidase-Hemoglobin from Amphitrite ornata Is Primarily a Monomer in Solution

    SciTech Connect

    M Thompson; S Franzen; M Davis; R Oliver; j Krueger; J Tredup; C Chang; J Khan; E Baldwin

    2011-12-31

    The crystal structures of the dehaloperoxidase-hemoglobin from A. ornata (DHP A) each report a crystallographic dimer in the unit cell. Yet, the largest dimer interface observed is 450 {angstrom}{sup 2}, an area significantly smaller than the typical value of 1200-2000 {angstrom}{sup 2} and in contrast to the extensive interface region of other known dimeric hemoglobins. To examine the oligomerization state of DHP A in solution, we used gel permeation by fast protein liquid chromatography and small-angle X-ray scattering (SAXS). Gel permeation experiments demonstrate that DHP A elutes as a monomer (15.5 kDa) and can be separated from green fluorescent protein, which has a molar mass of 27 kDa, near the 31 kDa expected for the DHP A dimer. By SAXS, we found that DHP A is primarily monomeric in solution, but with a detectable level of dimer (10%), under all conditions studied up to a protein concentration of 3.0 mM. These concentrations are likely 10-100-fold lower than the K{sub d} for dimer formation. Additionally, there was no significant effect either on the overall conformation of DHP A or its monomer-dimer equilibrium upon addition of the DHP A inhibitor, 4-iodophenol.

  12. Floral biology of two Vanilloideae (Orchidaceae) primarily adapted to pollination by euglossine bees.

    PubMed

    Pansarin, E R; Pansarin, L M

    2014-11-01

    Vanilloideae comprises 15 genera distributed worldwide, among which are Vanilla and Epistephium (tribe Vanilleae). Based on field and laboratory investigations, the pollination biology of V. dubia and E. sclerophyllum was analysed. The former was surveyed in a semi-deciduous mesophytic forest at the biological reserve of Serra do Japi and in a marshy forest at the city of Pradópolis, southeastern Brazil. The latter was examined in rocky outcrop vegetation in the Chapada Diamantina, northeastern Brazil. In the studied populations, the tubular flowers of V. dubia and E. sclerophyllum were pollinated by bees. Pollen was deposited on either their scutellum (V. dubia) or scutum (E. sclerophyllum). The mentum region of V. dubia is dry, whereas that of E. sclerophyllum presents a small quantity of dilute nectar. Flowers of E. sclerophyllum are scentless, while those of V. dubia are odoriferous. Although V. dubia is self-compatible, it needs a pollinator to produce fruit. In contrast, E. sclerophyllum sets fruit through spontaneous self-pollination, but biotic pollination also occurs. Both species are primarily adapted to pollination by euglossine bees. Pollination by Euglossina seems to have occurred at least twice during the evolution of Vanilleae. Furthermore, shifts between rewarding and reward-free flowers and between autogamous and allogamous species have been reported among vanillas.

  13. Asthma prevalence and risk factor assessment of an underserved and primarily Latino child population in Colorado.

    PubMed

    Clark, Maggie L; Reynolds, Stephen J; Hendrikson, Edward; Peel, Jennifer L

    2014-01-01

    Asthma is a substantialpublic health burden among children. Disease and risk-factor discrepancies have been identified among racial, ethnic, and socioeconomic groups. At a rural health clinic (Salud Family Health Center) with primarily underserved and Latino patients in Colorado, the authors evaluated 250 medical records and administered 57 parental surveys to describe this population with respect to asthma diagnosis, asthma-like symptoms, and environmental/occupational risk factors among children. Wheeze and asthma were indicated in 9.7% and 8.9% of medical records, respectively. Twenty parents (35.7%) reported in a questionnaire that their child had experienced wheezing or whistling in the chest. Parents reported that children play in farming fields (21.8%) and feed livestock/animals (10.9%). Additionally, 13.2% and 9.4% of children have a household member who works around livestock or around grain, feed, or dust, respectively. Information from the Salud population can be used to develop larger-scale research and public health initiatives to eliminate health and risk factor disparities among underserved children.

  14. Visual processing of informative multipoint correlations arises primarily in V2.

    PubMed

    Yu, Yunguo; Schmid, Anita M; Victor, Jonathan D

    2015-04-27

    Using the visual system as a model, we recently showed that the efficient coding principle accounted for the allocation of computational resources in central sensory processing: when sampling an image is the main limitation, resources are devoted to compute the statistical features that are the most variable, and therefore the most informative (eLife 2014;3:e03722. DOI: 10.7554/eLife.03722 Hermundstad et al., 2014). Building on these results, we use single-unit recordings in the macaque monkey to determine where these computations--sensitivity to specific multipoint correlations--occur. We find that these computations take place in visual area V2, primarily in its supragranular layers. The demonstration that V2 neurons are sensitive to the multipoint correlations that are informative about natural images provides a common computational underpinning for diverse but well-recognized aspects of neural processing in V2, including its sensitivity to corners, junctions, illusory contours, figure/ground, and 'naturalness.'

  15. Local field potentials primarily reflect inhibitory neuron activity in human and monkey cortex

    PubMed Central

    Teleńczuk, Bartosz; Dehghani, Nima; Le Van Quyen, Michel; Cash, Sydney S.; Halgren, Eric; Hatsopoulos, Nicholas G.; Destexhe, Alain

    2017-01-01

    The local field potential (LFP) is generated by large populations of neurons, but unitary contribution of spiking neurons to LFP is not well characterised. We investigated this contribution in multi-electrode array recordings from human and monkey neocortex by examining the spike-triggered LFP average (st-LFP). The resulting st-LFPs were dominated by broad spatio-temporal components due to ongoing activity, synaptic inputs and recurrent connectivity. To reduce the spatial reach of the st-LFP and observe the local field related to a single spike we applied a spatial filter, whose weights were adapted to the covariance of ongoing LFP. The filtered st-LFPs were limited to the perimeter of 800 μm around the neuron, and propagated at axonal speed, which is consistent with their unitary nature. In addition, we discriminated between putative inhibitory and excitatory neurons and found that the inhibitory st-LFP peaked at shorter latencies, consistently with previous findings in hippocampal slices. Thus, in human and monkey neocortex, the LFP reflects primarily inhibitory neuron activity. PMID:28074856

  16. Tribolium castaneum defensins are primarily active against Gram-positive bacteria.

    PubMed

    Tonk, Miray; Knorr, Eileen; Cabezas-Cruz, Alejandro; Valdés, James J; Kollewe, Christian; Vilcinskas, Andreas

    2015-11-01

    The red flour beetle Tribolium castaneum is a destructive insect pest of stored food and feed products, and a model organism for development, evolutionary biology and immunity. The insect innate immune system includes antimicrobial peptides (AMPs) with a wide spectrum of targets including viruses, bacteria, fungi and parasites. Defensins are an evolutionarily-conserved class of AMPs and a potential new source of antimicrobial agents. In this context, we report the antimicrobial activity, phylogenetic and structural properties of three T. castaneum defensins (Def1, Def2 and Def3) and their relevance in the immunity of T. castaneum against bacterial pathogens. All three recombinant defensins showed bactericidal activity against Micrococcus luteus and Bacillus thuringiensis serovar tolworthi, but only Def1 and Def2 showed a bacteriostatic effect against Staphylococcus epidermidis. None of the defensins showed activity against the Gram-negative bacteria Escherichia coli and Pseudomonas entomophila or against the yeast Saccharomyces cerevisiae. All three defensins were transcriptionally upregulated following a bacterial challenge, suggesting a key role in the immunity of T. castaneum against bacterial pathogens. Phylogenetic analysis showed that defensins from T. castaneum, mealworms, Udo longhorn beetle and houseflies cluster within a well-defined clade of insect defensins. We conclude that T. castaneum defensins are primarily active against Gram-positive bacteria and that other AMPs may play a more prominent role against Gram-negative species.

  17. Identification of a novel CoA synthase isoform, which is primarily expressed in Brain

    SciTech Connect

    Nemazanyy, Ivan . E-mail: nemazanyy@imbg.org.ua; Panasyuk, Ganna; Breus, Oksana; Zhyvoloup, Alexander; Filonenko, Valeriy; Gout, Ivan T. . E-mail: i.gout@ucl.ac.uk

    2006-03-24

    CoA and its derivatives Acetyl-CoA and Acyl-CoA are important players in cellular metabolism and signal transduction. CoA synthase is a bifunctional enzyme which mediates the final stages of CoA biosynthesis. In previous studies, we have reported molecular cloning, biochemical characterization, and subcellular localization of CoA synthase (CoASy). Here, we describe the existence of a novel CoA synthase isoform, which is the product of alternative splicing and possesses a 29aa extension at the N-terminus. We termed it CoASy {beta} and originally identified CoA synthase, CoASy {alpha}. The transcript specific for CoASy {beta} was identified by electronic screening and by RT-PCR analysis of various rat tissues. The existence of this novel isoform was further confirmed by immunoblot analysis with antibodies directed to the N-terminal peptide of CoASy {beta}. In contrast to CoASy {alpha}, which shows ubiquitous expression, CoASy {beta} is primarily expressed in Brain. Using confocal microscopy, we demonstrated that both isoforms are localized on mitochondria. The N-terminal extension does not affect the activity of CoA synthase, but possesses a proline-rich sequence which can bring the enzyme into complexes with signalling proteins containing SH3 or WW domains. The role of this novel isoform in CoA biosynthesis, especially in Brain, requires further elucidation.

  18. Species sorting and seasonal dynamics primarily shape bacterial communities in the Upper Mississippi River.

    PubMed

    Staley, Christopher; Gould, Trevor J; Wang, Ping; Phillips, Jane; Cotner, James B; Sadowsky, Michael J

    2015-02-01

    Bacterial community structure (BCS) in freshwater ecosystems varies seasonally and due to physicochemical gradients, but metacommunity structure of a major river remains understudied. Here we characterize the BCS along the Mississippi River and contributing rivers in Minnesota over three years using Illumina next-generation sequencing, to determine how changes in environmental conditions as well as inputs from surrounding land and confluences impacted community structure. Contributions of sediment to water microbial diversity were also evaluated. Long-term variation in community membership was observed, and significant shifts in relative abundances of major freshwater taxa, including α-Proteobacteria, Burkholderiales, and Actinomycetales, were observed due to temporal and spatial variations. Environmental parameters (e.g. temperature, rainfall, and nutrient concentrations) primarily contributed to differences in phyla abundances (88% of variance), with minimal influence from spatial distance alone (<1% of variance). Furthermore, an annually-recurrent BCS was observed in late summer, further suggesting that seasonal dynamics strongly influence community composition. Sediment communities differed from those in the water, but contributed up to 50% to community composition in the water column. Among water sampling sites, 34% showed significant variability in BCS of replicate samples indicating variability among riverine communities due to heterogeneity in the water column. Results of this study highlight the need for a better understanding of spatial and temporal variations in riverine bacterial diversity associated with physicochemical gradients and reveal how communities in sediments, and potentially other environmental reservoirs, impact waterborne BCS. Techniques used in this study may prove useful to determine sources of microbes from sediments and soils to waterways, which will facilitate best management practices and total maximum daily load determinations

  19. In vitro metabolism of piperaquine is primarily mediated by CYP3A4.

    PubMed

    Lee, Tina Ming-Na; Huang, Liusheng; Johnson, Marla K; Lizak, Patricia; Kroetz, Deanna; Aweeka, Francesca; Parikh, Sunil

    2012-11-01

    Piperaquine (PQ) is part of a first-line treatment regimen for Plasmodium falciparum malaria recommended by the World Health Organization (WHO). We aimed to determine the major metabolic pathway(s) of PQ in vitro. A reliable, validated tandem mass spectrometry method was developed. Concentrations of PQ were measured after incubation with both human liver microsomes (HLMs) and expressed cytochrome P450 enzymes (P450s). In pooled HLMs, incubations with an initial PQ concentration of 0.3 µM resulted in a 34.8 ± 4.9% loss of substrate over 60 min, corresponding to a turnover rate of 0.009 min(-1) (r(2) = 0.9223). Miconazole, at nonspecific P450 inhibitory concentrations, resulted in almost complete inhibition of PQ metabolism. The greatest inhibition was demonstrated with selective CYP3A4 (100%) and CYP2C8 (66%) inhibitors. Using a mixture of recombinant P450 enzymes, turnover for PQ metabolism was estimated as 0.0099 min(-1); recombinant CYP3A4 had a higher metabolic rate (0.017 min(-1)) than recombinant CYP2C8 (p < .0001). Inhibition of CYP3A4-mediated PQ loss was greatest using the selective inhibitor ketoconazole (9.1 ± 3.5% loss with ketoconazole vs 60.7 ± 5.9% with no inhibitor, p < .0001). In summary, the extent of inhibition of in vitro metabolism with ketoconazole (83%) denotes that PQ appears to be primarily catalyzed by CYP3A4. Further studies to support these findings through the identification and characterization of PQ metabolites are planned.

  20. In vitro metabolism of piperaquine is primarily mediated by CYP3A4

    PubMed Central

    Lee, Tina Ming-Na; Huang, Liusheng; Johnson, Marla K.; Lizak, Patricia; Kroetz, Deanna; Aweeka, Francesca; Parikh, Sunil

    2016-01-01

    Piperaquine (PQ) is part of a first-line treatment regimen for Plasmodium falciparum malaria recommended by the World Health Organization (WHO). We aimed to determine the major metabolic pathway(s) of PQ in vitro. A reliable, validated tandem mass spectrometry method was developed. Concentrations of PQ were measured after incubation with both human liver microsomes (HLMs) and expressed cytochrome P450 enzymes (P450s). In pooled HLMs, incubations with an initial PQ concentration of 0.3 µM resulted in a 34.8 ± 4.9% loss of substrate over 60 min, corresponding to a turnover rate of 0.009 min−1 (r2 = 0.9223). Miconazole, at nonspecific P450 inhibitory concentrations, resulted in almost complete inhibition of PQ metabolism. The greatest inhibition was demonstrated with selective CYP3A4 (100%) and CYP2C8 (66%) inhibitors. Using a mixture of recombinant P450 enzymes, turnover for PQ metabolism was estimated as 0.0099 min−1; recombinant CYP3A4 had a higher metabolic rate (0.017 min−1) than recombinant CYP2C8 (p < .0001). Inhibition of CYP3A4-mediated PQ loss was greatest using the selective inhibitor ketoconazole (9.1 ± 3.5% loss with ketoconazole vs 60.7 ± 5.9% with no inhibitor, p < .0001). In summary, the extent of inhibition of in vitro metabolism with ketoconazole (83%) denotes that PQ appears to be primarily catalyzed by CYP3A4. Further studies to support these findings through the identification and characterization of PQ metabolites are planned. PMID:22671777

  1. Self-reported health outcomes associated with green-renovated public housing among primarily elderly residents.

    PubMed

    Breysse, Jill; Dixon, Sherry L; Jacobs, David E; Lopez, Jorge; Weber, William

    2015-01-01

    Assess the benefits of green renovation on self-reported health of primarily elderly residents of a low-income public housing apartment building. Using questions from the Medicare Health Outcomes Survey, we interviewed residents at baseline and 1 year after green renovation of their 101-unit building in Mankato, Minnesota, comparing self-reported mental and physical health outcomes of 2 sets of residents (all-ages: median, 66 years, n = 40; elder: median, 72 years, n = 22) with outcomes for 2 same-aged low-income Minnesota comparison groups taken from Medicare Health Outcomes Survey participants (n = 40 and 572, respectively). Mankato apartment building residents. Green renovation including building envelope restoration; new heating, electrical, and ventilation systems; air sealing; new insulation and exterior cladding; window replacement; Energy-Star fixtures and appliances; asbestos and mold abatement; apartment gut retrofits; low volatile organic chemical and moisture-resistant materials; exercise enhancements; and indoor no-smoking policy. Self-reported health status including Activities of Daily Living and Veteran's Rand 12 (VR-12) survey results; housing condition visual assessment; indoor environmental sampling; and building performance testing. The all-ages study group's mental health improved significantly more than the comparison group's mental health on the basis of mean number of good mental health days in the past month (P = .026) and mean VR-12 mental component score (P = .023). Sixteen percent fewer all-ages study group people versus 8% more comparison group people reported falls (P = .055). The elder study group's 9% improvement in general physical health was not statistically significantly better than the elder comparison group's decline (6%) (P = 0.094). Significantly fewer people in the all-ages group reported smoke in their apartments because of tobacco products (20% vs 0%, P = .005), likely reflecting the new no-smoking policy. Green healthy

  2. Predictors of nephrectomy in high grade blunt renal trauma patients treated primarily with conservative intent.

    PubMed

    Prasad, Narla Hari; Devraj, Rahul; Chandriah, G Ram; Sagar, S Vidya; Reddy, Ch Ram; Murthy, Pisapati Venkata Lakshmi Narsimha

    2014-04-01

    There is no consensus on the optimal management of high grade renal trauma. Delayed surgery increases the likelihood of secondary hemorrhage and persistent urinary extravasation, whereas immediate surgery results in high renal loss. Hence, the present study was undertaken to evaluate the predictors of nephrectomy and outcome of high Grade (III-V) renal injury, treated primarily with conservative intent. The records of 55 patients who were admitted to our institute with varying degrees of blunt renal trauma from January 2005 to December 2012 were retrospectively reviewed. Grade III-V renal injury was defined as high grade blunt renal trauma and was present in 44 patients. The factors analyzed to predict emergency intervention were demographic profile, grade of injury, degree of hemodynamic instability, requirement of blood transfusion, need for intervention, mode of intervention, and duration of intensive care unit stay. Rest of the 40 patients with high grade injury (grade 3 and 4)did not require emergency intervention and underwent a trail of conservative management. 7 of the 40 patients with high grade renal injury (grade 3 and 4), who were managed conservatively experienced complications requiring procedural intervention and three required a delayed nephrectomy. Presence of grade V injuries with hemodynamic instability and requirement of more than 10 packed cell units for resuscitation were predictors of nephrectomy. Predictors of complications were urinary extravasation and hemodynamic instability at presentation. Majority of the high grade renal injuries can be successfully managed conservatively. Grade V injuries and the need for more packed cell transfusions during resuscitation predict the need for emergency intervention.

  3. Bleomycin, unlike other male-mouse mutagens, is most effective in spermatogonia, inducing primarily deletions.

    PubMed

    Russell, L B; Hunsicker, P R; Kerley, M K; Johnson, D K; Shelby, M D

    2000-08-21

    Dominant-lethal tests [P.D. Sudman, J.C. Rutledge, J.B. Bishop, W.M. Generoso, Bleomycin: female-specific dominant lethal effects in mice, Mutat. Res. 296 (1992) 205-217] had suggested that Bleomycin sulfate (Blenoxane), BLM, might be a female-specific mutagen. While confirming that BLM is indeed a powerful inducer of dominant-lethal mutations in females that fails to induce such mutations in postspermatogonial stages of males, we have shown in a specific-locus test that BLM is, in fact, mutagenic in males. This mutagenicity, however, is restricted to spermatogonia (stem-cell and differentiating stages), for which the specific-locus mutation rate differed significantly (P<0.008) from the historical control rate. In treated groups, dominant mutations, also, originated only in spermatogonia. With regard to mutation frequencies, this germ-cell-stage pattern is different from that for radiation and for any other chemical studied to date, except ethylnitrosourea (ENU). However, the nature of the spermatogonial specific-locus mutations differentiates BLM from ENU as well, because BLM induced primarily (or, perhaps, exclusively) multilocus deletions. Heretofore, no chemical that induced specific-locus mutations in spermatogonia did not also induce specific-locus as well as dominant-lethal mutations in postspermatogonial stages, making the dominant lethal test, up till now, predictive of male mutagenicity in general. The BLM results now demonstrate that there are chemicals that can induce specific-locus mutations in spermatogonia without testing positive in postspermatogonial stages. Thus, BLM, while not female-specific, is unique, (a) in its germ-cell-stage specificity in males, and (b) in inducing a type of mutation (deletions) that is atypical for the responding germ-cell stages (spermatogonia).

  4. Intramuscular adipose tissue determined by T1-weighted MRI at 3T primarily reflects extramyocellular lipids.

    PubMed

    Akima, Hiroshi; Hioki, Maya; Yoshiko, Akito; Koike, Teruhiko; Sakakibara, Hisataka; Takahashi, Hideyuki; Oshida, Yoshiharu

    2016-05-01

    The purpose of this study was to assess relationships between intramuscular adipose tissue (IntraMAT) content determined by MRI and intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) determined by (1)H magnetic resonance spectroscopy ((1)H MRS) or echo intensity determined by B-mode ultrasonography of human skeletal muscles. Thirty young and elderly men and women were included. T1-weighted MRI was taken from the right mid-thigh to measure IntraMAT content of the vastus lateralis (VL) and biceps femoris (BF) using a histogram shape-based thresholding technique. IMCL and EMCL were measured from the VL and BF at the right mid-thigh using (1)H MRS. Ultrasonographic images were taken from the VL and BF of the right mid-thigh to measure echo intensity based on gray-scale level for quantitative analysis. There was a significant correlation between IntraMAT content by MRI and EMCL of the VL and BF (VL, r=0.506, P<0.01; BF, r=0.591, P<0.001) and between echo intensity and EMCL of the VL and BF (VL, r=0.485, P<0.05; BF, r=0.648, P<0.01). IntraMAT content was also significantly correlated with echo intensity of the VL and BF (VL, r=0.404, P<0.05; BF, r=0.493, P<0.01). Our study suggests that IntraMAT content determined by T1-weighted MRI at 3T primarily reflects extramyocellular lipids, not intramyocellular lipids, in human skeletal muscles. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Improving Limits on Anomalous Pseudoscalar Interactions using Few Body Calculations

    NASA Astrophysics Data System (ADS)

    Aldaihan, Sheakha; Snow, William Michael; Krause, Dennis

    2016-09-01

    Exotic long-range spin-dependent interactions between nucleons can be generated by many possible sources beyond the Standard Model. Anomalous interactions arising from exchange of ultralight bosons with pseudoscalar couplings gP between free fermions are highly suppressed in the nonrelativistic limit due to their spin dependence and suppression factors associated with the parity change at the vertex. As a consequence the experimental limits on such interactions are several orders of magnitude weaker than limits on spin-independent Yukawa interactions. We call attention to a physical process in the interaction between nucleons in separate nuclei exchanging a light pseudoscalar first identified by Krause and Fischbach which can lead to a spin independent effect and, in combination with existing experimental constraints on exotic Yukawa interactions, can improve constraints on gP for interaction ranges of atomic and mesoscopic scales. Similar nuclei models can also be used to improve constraints on P and T odd long-range interactions between scalar and pseudoscalar vertices.The theoretical evaluations of this effect will require knowledge of parity-odd matrix elements in nuclei.

  6. 49 CFR 178.337 - Specification MC 331; cargo tank motor vehicle primarily for transportation of compressed gases...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Specification MC 331; cargo tank motor vehicle primarily for transportation of compressed gases as defined in subpart G of part 173 of this subchapter. 178... MC 331; cargo tank motor vehicle primarily for transportation of compressed gases as defined...

  7. 49 CFR 37.101 - Purchase or lease of vehicles by private entities not primarily engaged in the business of...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... not primarily engaged in the business of transporting people. 37.101 Section 37.101 Transportation... entities not primarily engaged in the business of transporting people. (a) Application. This section... business of transporting people, in which a solicitation for the vehicle is made after August 25, 1990. (b...

  8. 49 CFR 37.101 - Purchase or lease of vehicles by private entities not primarily engaged in the business of...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... not primarily engaged in the business of transporting people. 37.101 Section 37.101 Transportation... entities not primarily engaged in the business of transporting people. (a) Application. This section... business of transporting people, in which a solicitation for the vehicle is made after August 25, 1990. (b...

  9. Realization of a Quantum Integer-Spin Chain with Controllable Interactions

    DTIC Science & Technology

    2015-06-17

    physics experimentally. We demonstrate how spin-dependent forces on trapped ions can be used to engineer an effective system of interacting spin-1...site participate in the dynamics. We observe the time evolution of the system and verify its coherence by entangling a pair of effective three-level...appearing in spin liquids [16] and in the fractional quantum Hall effect . These characteristics suggest that the Haldane phase is one of the simplest

  10. Hypothyroidism in patients with bipolar I disorder treated primarily with lithium.

    PubMed

    Fagiolini, Andrea; Kupfer, David J; Scott, John; Swartz, Holly A; Cook, David; Novick, Danielle M; Frank, Ellen

    2006-01-01

    This study evaluated the frequency and clinical significance of abnormal Thyroid Stimulating Hormone (TSH) and Free Thyroxine Index (FTI) in patients with bipolar I disorder treated primarily with lithium. We evaluated the medical records of 143 participants in the Pittsburgh study of Maintenance Therapies in Bipolar Disorder who did not have a thyroid abnormality at entry. Thirty-six percent of the 143 patients developed abnormal TSH and/or FTI values. Thirty-eight percent of the 135 patients who received lithium developed abnormal TSH and/or FTI, spent significantly longer time in the acute treatment phase (t = -3.6, df = 133, p = .0004), and had significantly higher mean Hamilton Scale for Depression scores over the course of the maintenance phase (t = -2.3, df = 71.6, p = .03). Time on lithium and development of abnormal TSH and/or FTI were positively correlated (r = .25, p = .004). Thyroid dysfunction can be frequent in patients exposed to lithium treatment for bipolar I disorder; it also appears to be correlated with a slower response to acute treatment, and may be related to poorer quality of long-term remission. A prospective study is needed to confirm our findings and determine whether more aggressive thyroid replacement can optimize thyroid function to facilitate clinical recovery. Supported in part by National Institute of Mental Health Grants MH 029618 (Drs. Frank and Fagiolini) and MH 030915 (Drs. Kupfer and Fagiolini), and the Bosin Memorial Fund of The Pittsburgh Foundation (Drs. Fagiolini, Kupfer, Cook, Scott, Novick and Frank). Dr. Fagiolini is on the advisory board and a consultant to Pfizer Inc, and Bristol Myers Squibb, and is on the speaker bureau of Bristol Myers Squibb, Eli Lilly Italy, Pfizer Inc, and Shire. Dr. Frank is on the advisory board of Pfizer Inc. and Eli Lilly & Company, and is a consultant to Pfizer Italia and Servier Amerique. Dr. Kupfer is on the advisory board of Pfizer, Inc., Forest Pharmaceuticals, Inc., and Solvay

  11. Passerine Exposure to Primarily PCDFs and PCDDs in the River Floodplains Near Midland, Michigan, USA

    PubMed Central

    Zwiernik, Matthew J.; Seston, Rita M.; Coefield, Sarah J.; Plautz, Stephanie C.; Tazelaar, Dustin L.; Shotwell, Melissa S.; Bradley, Patrick W.; Kay, Denise P.; Giesy, John P.

    2009-01-01

    House wren (Troglodytes aedon), tree swallow (Tachycineta bicolor), and eastern bluebird (Sialia sialis) tissues collected in study areas (SAs) downstream of Midland, Michigan (USA) contained concentrations of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) greater than in upstream reference areas (RAs) in the region. The sum of concentrations of PCDD/DFs (ΣPCDD/DFs) in eggs of house wrens and eastern bluebirds from SAs were 4- to 22-fold greater compared to those from RAs, whereas concentrations in tree swallow eggs were similar among areas. Mean concentrations of ΣPCDD/DFs and sum 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (ΣTEQsWHO-Avian), based on 1998 WHO avian toxic equivalency factors, in house wren and eastern bluebird eggs ranged from 860 (430) to 1500 (910) ng/kg wet weight (ww) and 470 (150) to 1100 (510) ng/kg ww, respectively, at the most contaminated study areas along the Tittabawassee River, whereas mean concentrations in tree swallow eggs ranged from 280 (100) to 760 (280) ng/kg ww among all locations. Concentrations of ΣPCDD/DFs in nestlings of all studied species at SAs were 3- to 50-fold greater compared to RAs. Mean house wren, tree swallow, and eastern bluebird nestling concentrations of ΣPCDD/DFs and ΣTEQsWHO-Avian ranged from 350 (140) to 610 (300) ng/kg ww, 360 (240) to 1100 (860) ng/kg ww, and 330 (100) to 1200 (690) ng/kg ww, respectively, at SAs along the Tittabawassee River. Concentrations of ΣTEQsWHO-Avian were positively correlated with ΣPCDD/DF concentrations in both eggs and nestlings of all species studied. Profiles of relative concentrations of individual congeners were dominated by furan congeners (69–84%), primarily 2,3,7,8-tetrachlorodibenzofuran and 2,3,4,7,8-pentachlorodibenzofuran, for all species at SAs on the Tittabawassee and Saginaw rivers but were dominated by dioxin congeners at upstream RAs. Electronic supplementary material The online version of this article (doi:10

  12. Blast exposure in rats with body shielding is characterized primarily by diffuse axonal injury.

    PubMed

    Garman, Robert H; Jenkins, Larry W; Switzer, Robert C; Bauman, Richard A; Tong, Lawrence C; Swauger, Peter V; Parks, Steven A; Ritzel, David V; Dixon, C Edward; Clark, Robert S B; Bayir, Hülya; Kagan, Valerian; Jackson, Edwin K; Kochanek, Patrick M

    2011-06-01

    Blast-induced traumatic brain injury (TBI) is the signature insult in combat casualty care. Survival with neurological damage from otherwise lethal blast exposures has become possible with body armor use. We characterized the neuropathologic alterations produced by a single blast exposure in rats using a helium-driven shock tube to generate a nominal exposure of 35 pounds per square inch (PSI) (positive phase duration ∼ 4 msec). Using an IACUC-approved protocol, isoflurane-anesthetized rats were placed in a steel wedge (to shield the body) 7 feet inside the end of the tube. The left side faced the blast wave (with head-only exposure); the wedge apex focused a Mach stem onto the rat's head. The insult produced ∼ 25% mortality (due to impact apnea). Surviving and sham rats were perfusion-fixed at 24 h, 72 h, or 2 weeks post-blast. Neuropathologic evaluations were performed utilizing hematoxylin and eosin, amino cupric silver, and a variety of immunohistochemical stains for amyloid precursor protein (APP), glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule 1 (Iba1), ED1, and rat IgG. Multifocal axonal degeneration, as evidenced by staining with amino cupric silver, was present in all blast-exposed rats at all time points. Deep cerebellar and brainstem white matter tracts were most heavily stained with amino cupric silver, with the morphologic staining patterns suggesting a process of diffuse axonal injury. Silver-stained sections revealed mild multifocal neuronal death at 24 h and 72 h. GFAP, ED1, and Iba1 staining were not prominently increased, although small numbers of reactive microglia were seen within areas of neuronal death. Increased blood-brain barrier permeability (as measured by IgG staining) was seen at 24 h and primarily affected the contralateral cortex. Axonal injury was the most prominent feature during the initial 2 weeks following blast exposure, although degeneration of other neuronal processes was also present

  13. Passerine exposure to primarily PCDFs and PCDDs in the river floodplains near Midland, Michigan, USA.

    PubMed

    Fredricks, Timothy B; Zwiernik, Matthew J; Seston, Rita M; Coefield, Sarah J; Plautz, Stephanie C; Tazelaar, Dustin L; Shotwell, Melissa S; Bradley, Patrick W; Kay, Denise P; Giesy, John P

    2010-05-01

    House wren (Troglodytes aedon), tree swallow (Tachycineta bicolor), and eastern bluebird (Sialia sialis) tissues collected in study areas (SAs) downstream of Midland, Michigan (USA) contained concentrations of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) greater than in upstream reference areas (RAs) in the region. The sum of concentrations of PCDD/DFs (SigmaPCDD/DFs) in eggs of house wrens and eastern bluebirds from SAs were 4- to 22-fold greater compared to those from RAs, whereas concentrations in tree swallow eggs were similar among areas. Mean concentrations of SigmaPCDD/DFs and sum 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (SigmaTEQs(WHO-Avian)), based on 1998 WHO avian toxic equivalency factors, in house wren and eastern bluebird eggs ranged from 860 (430) to 1500 (910) ng/kg wet weight (ww) and 470 (150) to 1100 (510) ng/kg ww, respectively, at the most contaminated study areas along the Tittabawassee River, whereas mean concentrations in tree swallow eggs ranged from 280 (100) to 760 (280) ng/kg ww among all locations. Concentrations of SigmaPCDD/DFs in nestlings of all studied species at SAs were 3- to 50-fold greater compared to RAs. Mean house wren, tree swallow, and eastern bluebird nestling concentrations of SigmaPCDD/DFs and SigmaTEQs(WHO-Avian) ranged from 350 (140) to 610 (300) ng/kg ww, 360 (240) to 1100 (860) ng/kg ww, and 330 (100) to 1200 (690) ng/kg ww, respectively, at SAs along the Tittabawassee River. Concentrations of SigmaTEQs(WHO-Avian) were positively correlated with SigmaPCDD/DF concentrations in both eggs and nestlings of all species studied. Profiles of relative concentrations of individual congeners were dominated by furan congeners (69-84%), primarily 2,3,7,8-tetrachlorodibenzofuran and 2,3,4,7,8-pentachlorodibenzofuran, for all species at SAs on the Tittabawassee and Saginaw rivers but were dominated by dioxin congeners at upstream RAs.

  14. Young children's hand contact activities: an observational study via videotaping in primarily outdoor residential settings.

    PubMed

    Auyeung, Willa; Canales, Robert A; Beamer, Paloma; Ferguson, Alesia C; Leckie, James O

    2006-09-01

    Microlevel activity time series (MLATS) data were gathered on hand contact activities of 38 children (1-6 years old) by videotaping in primarily outdoor residential environments. The videotape recordings were then translated into text files using a specialized software called VirtualTimingDevicetrade mark. Contact frequency (contacts/h), duration per contact (s/contact), and hourly contact duration (min/h) were summarized for outdoor hand contacts with 15 distinct object/surface categories ("Animal", "Body", "Clothes/Towels", "Fabric", "Floor", "Food", "Footwear", "Metal", "Non-dietary Water", "Paper/Wrapper", "Plastic", "Rock/Brick", "Toys", "Vegetation/Grass", and "Wood") and two aggregate object/surface categories ("Non-dietary objects/surfaces" and "Total objects/surfaces"). For outdoor both hand contacts with "Total objects/surfaces", contact frequencies ranged from 229.9 to 1517.7 contacts/h, median durations/contact ranged from < 1 to 5 s, and hourly contact durations ranged from 42.6 to 102.2 m/h. The data were analyzed for significant differences in hand contact activities as a function of (1) age, (2) location, (3) gender, and (4) hand. Significant differences (P < or = 0.05) were found for all four factors analyzed. Hourly contact durations with "Non-dietary objects/surfaces" and "Total objects/surfaces" increased with age (P = 0.01, rs = 0.42 and P = 0.005, rs = 0.46, respectively), while contact frequencies and hourly contact durations with "Wood" decreased with age (P = 0.02, rs = -0.38 and P = 0.05, rs = -0.32, respectively). Location was found to affect contact frequencies and hourly contact durations with certain objects/surfaces. For example, contact frequencies and hourly contact durations with "Fabric" were higher indoors (P = 0.02 for both), while contact frequencies and hourly contact durations with "Vegetation/Grass" were higher outdoors (P = 0.02 and P = 0.04, respectively). Girls had longer hourly contact durations with "Footwear" (P = 0

  15. Patients With Adhesive Small Bowel Obstruction Should Be Primarily Managed by a Surgical Team.

    PubMed

    Aquina, Christopher T; Becerra, Adan Z; Probst, Christian P; Xu, Zhaomin; Hensley, Bradley J; Iannuzzi, James C; Noyes, Katia; Monson, John R T; Fleming, Fergal J

    2016-09-01

    To evaluate the impact of a primary medical versus surgical service on healthcare utilization and outcomes for adhesive small bowel obstruction (SBO) admissions. Adhesive-SBO typically requires hospital admission and is associated with high healthcare utilization and costs. Given that most patients are managed nonoperatively, many patients are admitted to medical hospitalists. However, comparisons of outcomes between primary medical and surgical services have been limited to small single-institution studies. Unscheduled adhesive-SBO admissions in NY State from 2002 to 2013 were identified using the Statewide Planning and Research Cooperative System. Bivariate and mixed-effects regression analyses were performed assessing factors associated with healthcare utilization and outcomes for SBO admissions. Among 107,603 admissions for adhesive-SBO (78% nonoperative, 22% operative), 43% were primarily managed by a medical attending and 57% were managed by a surgical attending. After controlling for patient, physician, and hospital-level factors, management by a medical service was independently associated with longer length of stay [IRR = 1.39, 95% confidence interval (CI) = 1.24, 1.56], greater inpatient costs (IRR = 1.38, 95% = 1.21, 1.57), and a higher rate of 30-day readmission (OR = 1.32, 95% CI = 1.22, 1.42) following nonoperative management. Similarly, of those managed operatively, management by a medicine service was associated with a delay in time to surgical intervention (IRR = 1.84, 95% CI = 1.69, 2.01), extended length of stay (IRR=1.36, 95% CI = 1.25, 1.49), greater inpatient costs (IRR = 1.38, 95% CI = 1.11, 1.71), and higher rates of 30-day mortality (OR = 1.92, 95% CI = 1.50, 2.47) and 30-day readmission (OR = 1.13, 95% CI = 0.97, 1.32). This study suggests that management of patients presenting with adhesive-SBO by a primary medical team is associated with higher healthcare utilization and worse perioperative outcomes. Policies favoring primary management

  16. Both cell substratum regulation and hormonal regulation of milk protein gene expression are exerted primarily at the posttranscriptional level

    SciTech Connect

    Eisenstein, R.S.; Rosen, J.M.

    1988-08-01

    The mechanism by which individual peptide and steroid hormones and cell-substratum interactions regulate milk protein gene expression has been studied in the COMMA-D mammary epithelial cell line. In the presence of insulin, hydrocortisone, and prolactin, growth of COMMA-D cells on floating collagen gels in comparison with that on a plastic substratum resulted in a 2.5- to 3-fold increase in the relative rate of ..beta..-casein gene transcription but a 37-fold increase in ..beta..-casein mRNA accumulation. In contrast, whey acidic protein gene transcription was constitutive in COMMA-D cells grown on either substratum, but its mRNA was unstable and little intact mature mRNA was detected. Culturing COMMA-D cells on collagen also promoted increased expression of other genes expressed in differentiated mammary epithelial cells, including those encoding ..cap alpha..- and ..gamma..-casein, transferrin, malic enzyme, and phosphoenolpyruvate carboxykinase but decreased the expression of actin and histone genes. Using COMMA-D cells, the authors defined further the role of individual hormones in influencing ..beta..-casein gene transcription. With insulin alone, a basal level of ..beta..-casein gene transcription was detected in COMMA-D cells grown on floating collagen gels. Addition of prolactin but not hydrocortisone resulted in a 2.5- to 3.0-fold increase in ..beta..-casein gene transcription, but both hormones were required to elicit the maximal 73-fold induction in mRNA accumulation. The posttranscriptional effect of hormones on casein mRNA accummulation preceded any detectable changes in the relative rate of transcription. Thus, regulation by both hormones and cell substratum of casein gene expression is exerted primarily at the post transcriptional level.

  17. Orsay, Santeuil and Le Blanc viruses primarily infect intestinal cells in Caenorhabditis nematodes.

    PubMed

    Franz, Carl J; Renshaw, Hilary; Frezal, Lise; Jiang, Yanfang; Félix, Marie-Anne; Wang, David

    2014-01-05

    The discoveries of Orsay, Santeuil and Le Blanc viruses, three viruses infecting either Caenorhabditis elegans or its relative Caenorhabditis briggsae, enable the study of virus-host interactions using natural pathogens of these two well-established model organisms. We characterized the tissue tropism of infection in Caenorhabditis nematodes by these viruses. Using immunofluorescence assays targeting proteins from each of the viruses, and in situ hybridization, we demonstrate viral proteins and RNAs localize to intestinal cells in larval stage Caenorhabditis nematodes. Viral proteins were detected in one to six of the 20 intestinal cells present in Caenorhabditis nematodes. In Orsay virus-infected C. elegans, viral proteins were detected as early as 6h post-infection. The RNA-dependent RNA polymerase and capsid proteins of Orsay virus exhibited different subcellular localization patterns. Collectively, these observations provide the first experimental insights into viral protein expression in any nematode host, and broaden our understanding of viral infection in Caenorhabditis nematodes.

  18. Basolateral Uptake of Nucleosides by Sertoli Cells Is Mediated Primarily by Equilibrative Nucleoside Transporter 1

    PubMed Central

    Klein, David M.; Evans, Kristen K.; Hardwick, Rhiannon N.; Dantzler, William H.; Wright, Stephen H.

    2013-01-01

    The blood-testis barrier (BTB) prevents the entry of many xenobiotic compounds into seminiferous tubules thereby protecting developing germ cells. Understanding drug transport across the BTB may improve drug delivery into the testis. Members of one class of drug, nucleoside reverse transcriptase inhibitors (NRTIs), do penetrate the BTB, presumably through interaction with physiologic nucleoside transporters. By investigating the mechanism of nucleoside transport, it may be possible to design other drugs to bypass the BTB in a similar manner. We present a novel ex vivo technique to study transport at the BTB that employs isolated, intact seminiferous tubules. Using this system, we found that over 80% of total uptake by seminiferous tubules of the model nucleoside uridine could be inhibited by 100 nM nitrobenzylmercaptopurine riboside (NBMPR, 6-S-[(4-nitrophenyl)methyl]-6-thioinosine), a concentration that selectively inhibits equilibrative nucleoside transporter 1 (ENT1) activity. In primary cultured rat Sertoli cells, 100 nM NBMPR inhibited all transepithelial transport and basolateral uptake of uridine. Immunohistochemical staining showed ENT1 to be located on the basolateral membrane of human and rat Sertoli cells, whereas ENT2 was located on the apical membrane of Sertoli cells. Transepithelial transport of uridine by rat Sertoli cells was partially inhibited by the NRTIs zidovudine, didanosine, and tenofovir disoproxil fumarate, consistent with an interaction between these drugs and ENT transporters. These data indicate that ENT1 is the primary route for basolateral nucleoside uptake into Sertoli cells and a possible mechanism for nucleosides and nucleoside-based drugs to undergo transepithelial transport. PMID:23639800

  19. Basolateral uptake of nucleosides by Sertoli cells is mediated primarily by equilibrative nucleoside transporter 1.

    PubMed

    Klein, David M; Evans, Kristen K; Hardwick, Rhiannon N; Dantzler, William H; Wright, Stephen H; Cherrington, Nathan J

    2013-07-01

    The blood-testis barrier (BTB) prevents the entry of many xenobiotic compounds into seminiferous tubules thereby protecting developing germ cells. Understanding drug transport across the BTB may improve drug delivery into the testis. Members of one class of drug, nucleoside reverse transcriptase inhibitors (NRTIs), do penetrate the BTB, presumably through interaction with physiologic nucleoside transporters. By investigating the mechanism of nucleoside transport, it may be possible to design other drugs to bypass the BTB in a similar manner. We present a novel ex vivo technique to study transport at the BTB that employs isolated, intact seminiferous tubules. Using this system, we found that over 80% of total uptake by seminiferous tubules of the model nucleoside uridine could be inhibited by 100 nM nitrobenzylmercaptopurine riboside (NBMPR, 6-S-[(4-nitrophenyl)methyl]-6-thioinosine), a concentration that selectively inhibits equilibrative nucleoside transporter 1 (ENT1) activity. In primary cultured rat Sertoli cells, 100 nM NBMPR inhibited all transepithelial transport and basolateral uptake of uridine. Immunohistochemical staining showed ENT1 to be located on the basolateral membrane of human and rat Sertoli cells, whereas ENT2 was located on the apical membrane of Sertoli cells. Transepithelial transport of uridine by rat Sertoli cells was partially inhibited by the NRTIs zidovudine, didanosine, and tenofovir disoproxil fumarate, consistent with an interaction between these drugs and ENT transporters. These data indicate that ENT1 is the primary route for basolateral nucleoside uptake into Sertoli cells and a possible mechanism for nucleosides and nucleoside-based drugs to undergo transepithelial transport.

  20. Exciton-plasmon and spin-plasmon interactions in hybrid semiconductor-metal nanostructures

    NASA Astrophysics Data System (ADS)

    Govorov, Alexander

    2011-03-01

    Coulomb and electromagnetic interactions between excitons and plasmons in nanocrystals cause several effects: energy transfer between nanoparticles, plasmon enhancement, Lamb shifts of exciton lines, Fano interference. In a complex composed of semiconductor quantum dot and metal nanoparticle, plasmons interact with spin-polarized excitons. This interaction leads to the formation of coupled spin-plasmon excitations and to spin-dependent Fano resonances. If an exciton-plasmon system includes chiral elements (chiral molecules or nanocrystals), the exciton-plasmon interaction is able to create new plasmonic lines in circular dichroism spectra.

  1. Vector meson-baryon interaction to study dynamical generation of resonances

    SciTech Connect

    Khemchandani, K. P.; Hosaka, A.; Kaneko, H.; Nagahiro, H.

    2011-10-21

    With the motivation to find dynamical generation of resonances, we study vector-meson baryon interaction by taking s-,t-,u-channel diagrams and a contact interaction into account. A comparison of the different contributions obtained from these diagrams is done in the SU(2) limit, which shows that these diagrams could be equally important. We find it worthwhile to pay attention to the structure of the total interaction between the two non-zero spin particles which possess similar masses and find spin dependent interaction similar to the nucleon-nucleon case.

  2. Parasites Affect Food Web Structure Primarily through Increased Diversity and Complexity

    PubMed Central

    Dunne, Jennifer A.; Lafferty, Kevin D.; Dobson, Andrew P.; Hechinger, Ryan F.; Kuris, Armand M.; Martinez, Neo D.; McLaughlin, John P.; Mouritsen, Kim N.; Poulin, Robert; Reise, Karsten; Stouffer, Daniel B.; Thieltges, David W.; Williams, Richard J.; Zander, Claus Dieter

    2013-01-01

    Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites “dominate” food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites' roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites' feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic organization

  3. Parasites affect food web structure primarily through increased diversity and complexity.

    PubMed

    Dunne, Jennifer A; Lafferty, Kevin D; Dobson, Andrew P; Hechinger, Ryan F; Kuris, Armand M; Martinez, Neo D; McLaughlin, John P; Mouritsen, Kim N; Poulin, Robert; Reise, Karsten; Stouffer, Daniel B; Thieltges, David W; Williams, Richard J; Zander, Claus Dieter

    2013-01-01

    Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites "dominate" food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites' roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites' feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic organization

  4. Parasites affect food web structure primarily through increased diversity and complexity

    USGS Publications Warehouse

    Dunne, Jennifer A.; Lafferty, Kevin D.; Dobson, Andrew P.; Hechinger, Ryan F.; Kuris, Armand M.; Martinez, Neo D.; McLaughlin, John P.; Mouritsen, Kim N.; Poulin, Robert; Reise, Karsten; Stouffer, Daniel B.; Thieltges, David W.; Williams, Richard J.; Zander, Claus Dieter

    2013-01-01

    Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites ‘‘dominate’’ food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites’ roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites’ feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic

  5. Conceptual knowledge for understanding other's actions is organized primarily around action goals.

    PubMed

    van Elk, M; van Schie, H T; Bekkering, H

    2008-07-01

    Semantic knowledge about objects entails both knowing how to grasp an object (grip-related knowledge) and what to do with an object (goal-related knowledge). Considerable evidence suggests a hierarchical organization in which specific hand-grips in action execution are most often selected to accomplish a remote action goal. The present study aimed to investigate whether a comparable hierarchical organization of semantic knowledge applies to the recognition of other's object-directed actions as well. Correctness of either the Grip (hand grip applied to the object) or the Goal (end-location at which an object was directed) were manipulated independently in two experiments. In Experiment 1, subjects were required to attend selectively to either the correctness of the grip or the goal of the observed action. Subjects were faster when attending to the goal of the action and a strong interference of goal-violations was observed when subjects attended to the grip of the action. Importantly, observation of irrelevant goal- or grip-related violations interfered with making decisions about the correctness of the relevant dimension only when the relevant dimension was correct. In contrast, in Experiment 2, when subjects attended to an action-irrelevant stimulus dimension (i.e. orientation of the object), no interference of goal- or grip-related violations was found, ruling out the possibility that interference-effects result from perceptual differences between stimuli. These findings suggest that understanding the correctness of an action selectively recruits specialized, but interacting networks, processing the correctness of goal- and grip-specific information during action observation.

  6. Constraints on anomalous spin-spin interactions from spin-exchange collisions

    SciTech Connect

    Jackson Kimball, D. F.; Boyd, Alec; Budker, D.

    2010-12-15

    A comparison between existing measurements and calculated cross sections for spin exchange between alkali-metal atoms and noble gases (specifically sodium and helium) is used to constrain anomalous spin-dependent forces between nuclei at the atomic scale ({approx}10{sup -8} cm). Combined with existing stringent limits on anomalous short-range, spin-dependent couplings of the proton, the dimensionless coupling constant for an axial vector interaction of the neutron arising from exchange of a boson of mass < or approx. 100 eV is constrained to be g{sub A}{sup n}/{radical}(4{pi}({h_bar}/2{pi})c)<2x10{sup -3}. Constraints are established for a velocity- and spin-dependent interaction {proportional_to}(I{center_dot}v)(K{center_dot}v), where I and K are the nuclear spins of He and Na, respectively, and v is the relative velocity of the atoms. Constraints on torsion gravity are also considered.

  7. Engineered long-range interactions on a 2D array of trapped ions

    NASA Astrophysics Data System (ADS)

    Britton, Joseph W.; Sawyer, Brian C.; Bollinger, John J.; Freericks, James K.

    2014-03-01

    Ising interactions are one paradigm used to model quantum magnetism in condensed matter systems. At NIST Boulder we confine and Doppler laser cool hundreds of 9Be+ ions in a Penning trap. The valence electron of each ion behaves as an ideal spin-1/2 particle and, in the limit of weak radial confinement relative to axial confinement, the ions naturally form a two-dimensional triangular lattice. A variable-range anti-ferromagnetic Ising interaction is engineered with a spin-dependent optical dipole force (ODF) through spin-dependent excitation of collective modes of ion motion. We have also exploited this spin-dependent force to perform spectroscopy and thermometry of the normal modes of the trapped ion crystal. The high spin-count and long-range spin-spin couplings achievable in the NIST Penning trap brings within reach simulation of computationally intractable problems in quantum magnetism. Examples include modeling quantum magnetic phase transitions and propagation of spin correlations resulting from a quantum quench. The Penning system may also be amenable to observation of spin-liquid behavior thought to arise in systems where the underlying lattice structure can frustrate long-range ordering. Supported by DARPA OLE and NIST.

  8. Topological spin-orbit interaction of light in anisotropic inhomogeneous subwavelength structures.

    PubMed

    Niv, Avi; Gorodetski, Yuri; Kleiner, Vladimir; Hasman, Erez

    2008-12-15

    Spin-orbit interaction resulting from spatial polarization state manipulation is demonstrated. Polarization-state manipulation is achieved by utilizing the effective birefringent nature of subwavelength structures acting as an anisotropic inhomogeneous medium. Experimental verification is obtained by measuring the effect of the unavoidable spin-dependent Pancharatnam-Berry phase modulation on the far-field diffraction pattern of the beam. Unlike the usual dynamic spin-orbit interaction that splits spin states in the temporal frequency (energy) domain, this topological spin-orbit interaction results in the splitting of spin states degenerated by their spatial frequencies (momentum).

  9. 49 CFR 37.107 - Acquisition of passenger rail cars by private entities primarily engaged in the business of...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Acquisition of passenger rail cars by private entities primarily engaged in the business of transporting people. 37.107 Section 37.107 Transportation Office of the Secretary of Transportation TRANSPORTATION SERVICES FOR INDIVIDUALS WITH DISABILITIES...

  10. 49 CFR 37.101 - Purchase or lease of vehicles by private entities not primarily engaged in the business of...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Purchase or lease of vehicles by private entities not primarily engaged in the business of transporting people. 37.101 Section 37.101 Transportation Office of the Secretary of Transportation TRANSPORTATION SERVICES FOR INDIVIDUALS WITH DISABILITIES...

  11. Transformative Undergraduate Science Courses for Non-Majors at a Historically Black Institution and at a Primarily White Institution

    ERIC Educational Resources Information Center

    Marbach-Ad, Gili; McGinnis, J. Randy; Pease, Rebecca; Dai, Amy; Benson, Spencer; Dantley, Scott Jackson

    2010-01-01

    We investigated curricular and pedagogical innovations in undergraduate science courses for non-science majors at a Historically Black Institution (HBI) and a Primarily White Institution (PWI). The aims were to improve students' understanding of science, increase their enthusiasm towards science by connecting their prior experience and interest to…

  12. 49 CFR 37.107 - Acquisition of passenger rail cars by private entities primarily engaged in the business of...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... transporting people and whose operations affect commerce, which remanufactures a rail passenger car to be used... 49 Transportation 1 2011-10-01 2011-10-01 false Acquisition of passenger rail cars by private entities primarily engaged in the business of transporting people. 37.107 Section 37.107...

  13. Combined effect of coherent Z exchange and the hyperfine interaction in the atomic parity-nonconserving interaction

    SciTech Connect

    Johnson, W.R.; Safronova, M.S.; Safronova, U.I.

    2003-06-01

    The nuclear spin-dependent parity-nonconserving (PNC) interaction arising from a combination of the hyperfine interaction and the coherent, spin-independent, PNC interaction from Z exchange is evaluated using many-body perturbation theory. For the 6s{sub 1/2}-7s{sub 1/2} transition in {sup 133}Cs, we obtain a result that is about 40% smaller than that found previously by Bouchiat and Piketty [Phys. Lett. B 269, 195 (1991)]. Applying this result to {sup 133}Cs leads to an increase in the experimental value of nuclear anapole moment and exacerbates differences between constraints on PNC meson coupling constants obtained from the Cs anapole moment and those obtained from other nuclear parity violating experiments. Nuclear spin-dependent PNC dipole matrix elements, including contributions from the combined weak-hyperfine interaction, are also given for the 7s{sub 1/2}-8s{sub 1/2} transition in {sup 211}Fr and for transitions between ground-state hyperfine levels in K, Rb, Cs, Ba{sup +}, Au, Tl, Fr, and Ra{sup +}.

  14. An altered form of pp60/sup c-src/ is expressed primarily in the central nervous system

    SciTech Connect

    Le Beau, J.M.; Wiestler, O.D.; Walter, G.

    1987-11-01

    The expression of two forms of pp60/sup c-scr/, pp60 and pp60/sup +/, was measured in the central nervous system (CNS) and the peripheral nervous system. Both forms were expressed in the CNS, whereas only pp60 was primarily detected in the peripheral nervous system. Our findings suggest that pp60/sup +/ may play a role in events important to the CNS.

  15. Prognostic Cell Biological Markers in Cervical Cancer Patients Primarily Treated With (Chemo)radiation: A Systematic Review

    SciTech Connect

    Noordhuis, Maartje G.; Eijsink, Jasper J.H.; Roossink, Frank; Graeff, Pauline de; Pras, Elisabeth; Schuuring, Ed; Wisman, G. Bea A.; Bock, Geertruida H. de; Zee, Ate G.J. van der

    2011-02-01

    The aim of this study was to systematically review the prognostic and predictive significance of cell biological markers in cervical cancer patients primarily treated with (chemo)radiation. A PubMed, Embase, and Cochrane literature search was performed. Studies describing a relation between a cell biological marker and survival in {>=}50 cervical cancer patients primarily treated with (chemo)radiation were selected. Study quality was assessed, and studies with a quality score of 4 or lower were excluded. Cell biological markers were clustered on biological function, and the prognostic and predictive significance of these markers was described. In total, 42 studies concerning 82 cell biological markers were included in this systematic review. In addition to cyclooxygenase-2 (COX-2) and serum squamous cell carcinoma antigen (SCC-ag) levels, markers associated with poor prognosis were involved in epidermal growth factor receptor (EGFR) signaling (EGFR and C-erbB-2) and in angiogenesis and hypoxia (carbonic anhydrase 9 and hypoxia-inducible factor-1{alpha}). Epidermal growth factor receptor and C-erbB-2 were also associated with poor response to (chemo)radiation. In conclusion, EGFR signaling is associated with poor prognosis and response to therapy in cervical cancer patients primarily treated with (chemo)radiation, whereas markers involved in angiogenesis and hypoxia, COX-2, and serum SCC-ag levels are associated with a poor prognosis. Therefore, targeting these pathways in combination with chemoradiation may improve survival in advanced-stage cervical cancer patients.

  16. Drug-induced taste and smell disorders. Incidence, mechanisms and management related primarily to treatment of sensory receptor dysfunction.

    PubMed

    Henkin, R I

    1994-11-01

    Drugs in every major pharmacological category can impair both taste and smell function and do so more commonly than presently appreciated. Impairment usually affects sensory function at a molecular level, causing 2 major behavioural changes--loss of acuity (i.e. hypogeusia and hyposmia) and/or distortion of function (i.e. dysgeusia and dysosmia). These changes can impair appetite, food intake, cause significant lifestyle changes and may require discontinuation of drug administration. Loss of acuity occurs primarily by drug inactivation of receptor function through inhibition of tastant/odorant receptor: (i) binding; (ii) Gs protein function; (iii) inositol trisphosphate function; (iv) channel (Ca++,Na++) activity; (v) other receptor inhibiting effects; or (vi) some combination of these effects. Distortions occur primarily by a drug inducing abnormal persistence of receptor activity (i.e. normal receptor inactivation does not occur) or through failure to activate: (i) various receptor kinases; (ii) Gi protein function; (iii) cytochrome P450 enzymes; or other effects which usually (iv) turn off receptor function; (v) inactivate tastant/odorant receptor binding; or (vi) some combination of these effects. Termination of drug therapy is commonly associated with termination of taste/smell dysfunction, but occasionally effects persist and require specific therapy to alleviate symptoms. Treatment primarily requires restoration of normal sensory receptor growth, development and/or function. Treatment which restores sensory acuity requires correction of steps initiating receptor and other pathology and includes zinc, theophylline, magnesium and fluoride. Treatment which inhibits sensory distortions requires reactivation of biochemical inhibition at the receptor or inactivation of inappropriate stimulus receptor binding and/or correction of other steps initiating pathology including dopaminergic antagonists, gamma-aminobutyric acid (GABA)-ergic agonists, calcium channel

  17. Kobayashi-Kondo-Maskawa-'t Hooft interaction in pentaquarks

    SciTech Connect

    Dmitrasinovic, V.

    2005-05-01

    We review critically the predictions of pentaquarks in the quark model, in particular, those based on the flavor-spin-dependent (Glozman-Riska) hyperfine interaction and the color-spin (one-gluon-exchange Fermi-Breit) one. We include the antiquark interactions and find that: (1) the exotic SU(3) multiplets are not substantially affected in the flavor-spin model, whereas some of the nonexotic multiplets are; and (2) the variational upper bound on the {xi}{sup --}-{theta}{sup +} mass difference in the color-spin hyperfine interaction model is substantially reduced. This leads us to the U{sub A}(1) symmetry breaking Kobayashi-Kondo-Maskawa-'tHooft interaction. We discuss some of its phenomenological consequences for pentaquarks.

  18. Intra-atomic aspects of magnon-plasmon interactions

    NASA Astrophysics Data System (ADS)

    Skomski, R.; Dowben, P. A.

    2006-04-01

    Magnon-plasmon interactions are modeled by considering the spin-dependent dielectric response of atoms placed in crystalline environment. Hund's exchange rules favor parallel spin alignment, but the strength of the exchange depends on the displacement of the centers of gravity of the atomic spin-up and spin-down electron charge clouds. The intra-atomic exchange is modeled by considering a Hubbard-type interaction, and interatomic interaction then yields a k-space dispersion. The eigenmodes of the plasma are a mixture of spin-up and spin-down degrees of freedom, described by a 2×2 interaction matrix. Minority and majority bands yield different plasmon frequencies. However, these modes are not orthogonal but coupled by intra-atomic exchange and obtained by explicit matrix diagonalization. The effect is largest for small wave vectors, in agreement with experiment.

  19. Outbreak of Serogroup C Meningococcal Disease Primarily Affecting Men Who Have Sex with Men - Southern California, 2016.

    PubMed

    Nanduri, Srinivas; Foo, Chelsea; Ngo, Van; Jarashow, Claire; Civen, Rachel; Schwartz, Ben; Holguin, John; Shearer, Eric; Zahn, Matt; Harriman, Kathleen; Winter, Kathleen; Kretz, Cecilia; Chang, How Yi; Meyer, Sarah; MacNeil, Jessica

    2016-09-09

    During March 4-August 11, 2016, 25 outbreak-associated cases of meningococcal disease, including two deaths (8% case-fatality ratio), were reported in Southern California. Twenty-four of the cases were caused by serogroup C Neisseria meningitidis (NmC) and one by N. meningitidis with an undetermined serogroup (Figure). On June 24, 2016, in response to this increase in NmC cases, primarily among men who have sex with men (MSM) in Los Angeles County, the city of Long Beach, and Orange County, the California Department of Public Health (CDPH) issued a press release and health advisory, declaring an outbreak of NmC in Southern California (1).

  20. Spin dependent magnetoresistance at ferromagnet/superconductor/ferromagnet La{sub 0.7}Ca{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7-delta}/La{sub 0.7}Ca{sub 0.3}MnO{sub 3} trilayers.

    SciTech Connect

    Visani, C.; Pena, V.; Garcia-Barriocanal, J.; Arias, D.; Sefrioui, Z.; Leon, C.; Santamaria, J.; Nemes, N. M.; Garcia-Hernandez, M.; Martinez, J. L.; te Velthuis, S.G.E; Hoffmann, A.; Materials Science Division; Univ. Complutense de Madrid; Inst. de Ciencia de Materiales de Madrid

    2007-01-01

    We report on large magnetoresistance in ferromagnet/superconductor/ferromagnet trilayer structures made of La{sub 0.7}Ca{sub 0.3}MnO{sub 3} and YBa{sub 2}Cu{sub 3}O{sub 7}. We find that the shape and height of the magnetoresistance peaks are not modified when the relative orientation of current and magnetic field is changed from parallel to perpendicular. Furthermore, we find that the temperature shift of the resistance curves is independent of current and of the sweep rate of the magnetic field. These observations favor the view that the magnetoresistance phenomenon originates in the spin dependent transport of quasiparticles transmitted from the ferromagnetic electrodes into the superconductor, and rule out interpretations in terms of spontaneous vortices or anisotropic magnetoresistance of the ferromagnetic layers.

  1. Borrelia burgdorferi Oxidative Stress Regulator BosR Directly Represses Lipoproteins Primarily Expressed in the Tick during Mammalian Infection

    PubMed Central

    Wang, Peng; Dadhwal, Poonam; Cheng, Zhihui; Zianni, Michael R.; Rikihisa, Yasuko; Liang, Fang Ting; Li, Xin

    2013-01-01

    Summary Differential gene expression is a key strategy adopted by the Lyme disease spirochaete, Borrelia burgdorferi, for adaptation and survival in the mammalian host and the tick vector. Many B. burgdorferi surface lipoproteins fall into two distinct groups according to their expression patterns: one group primarily expressed in the tick and the other group primarily expressed in the mammal. Here, we show that the Fur homologue in this bacterium, also known as Borrelia oxidative stress regulator (BosR), is required for repression of outer surface protein A (OspA) and OspD in the mammal. Furthermore, BosR binds directly to sequences upstream of the ospAB operon and the ospD gene through recognition of palindromic motifs similar to those recognized by other Fur homologues but with a 1-bp variation in the spacer length. Putative BosR-binding sites have been identified upstream of 156 B. burgdorferi genes. Some of these genes share the same expression pattern as ospA and ospD. Most notably, 12 (67%) of the 18 genes previously identified in a genome-wide microarray study to be most significantly repressed in the mammal are among the putative BosR regulon. These data indicate that BosR may directly repress transcription of many genes that are down-regulated in the mammal. PMID:23869590

  2. FADD Expression as a Prognosticator in Early-Stage Glottic Squamous Cell Carcinoma of the Larynx Treated Primarily With Radiotherapy

    SciTech Connect

    Schrijvers, Michiel L.; Pattje, Wouter J.; Slagter-Menkema, Lorian; Mastik, Mirjam F.; Gibcus, Johan H.; Langendijk, Johannes A.; Wal, Jacqueline E. van der; Laan, Bernard F.A.M. vn der

    2012-07-15

    Purpose: We recently reported on the identification of the Fas-associated death domain (FADD) as a possible driver of the chromosome 11q13 amplicon and the association between increased FADD expression and disease-specific survival in advanced-stage laryngeal carcinoma. The aim of this study was to examine whether expression of FADD and its Ser194-phosphorylated isoform (pFADD) predicts local control in patients with early-stage glottic carcinoma primarily treated with radiotherapy only. Methods and Materials: Immunohistochemical staining for FADD and pFADD was performed on pretreatment biopsy specimens of 92 patients with T1-T2 glottic squamous cell carcinoma primarily treated with radiotherapy between 1996 and 2005. Cox regression analysis was used to correlate expression levels with local control. Results: High levels of pFADD were associated with significantly better local control (hazard ratio, 2.40; 95% confidence interval, 1.04-5.55; p = 0.040). FADD overexpression showed a trend toward better local control (hazard ratio, 3.656; 95% confidence interval, 0.853-15.663; p = 0.081). Multivariate Cox regression analysis showed that high pFADD expression was the best predictor of local control after radiotherapy. Conclusions: This study showed that expression of phosphorylated FADD is a new prognostic biomarker for better local control after radiotherapy in patients with early-stage glottic carcinomas.

  3. Mating-type orthologous genes in the primarily homothallic Moniliophthora perniciosa, the causal agent of Witches' Broom Disease in cacao.

    PubMed

    Kües, Ursula; Navarro-González, Mónica

    2010-10-01

    The cacao-pathogenic Moniliophthora perniciosa C-biotype is a primarily homothallic Agaricomycete of which the genome has recently become available. Searching of the genome sequence with mating type proteins from other basidiomycetes detected one or possibly two potential genes for HD1 homeodomain transcription factors, 7 or possibly 8 genes for potential pheromone receptors and five genes for putative pheromone precursors. Apparently, the fungus possesses gene functions encoded in the tetrapolar basidiomycetes in the A and B mating loci, respectively. In the tetrapolar species, the A and B mating type genes govern formation of clamp cells at hyphal septa of the dikaryon and their fusion with sub-apical cells as well as mushroom production. The C-biotype forms fused clamp cells and also basidiocarps on mycelia germinated from basidiospores and their development might be controlled by the detected genes. It represents the first example of a primarily homothallic basidiomycete where A - and B -mating-type-like genes were found. Various strategies are discussed as how self-compatibility in presence of such genes can evolve. An A -mating-type like gene for an HD2 homeodomain transcription factor is, however, not included in the available sequence representing estimated 69% coverage of the haploid genome but there are non-mating genes for other homeodomain transcription factors of currently unknown function that are conserved in basidiomycetes and also various ascomycetes.

  4. Engaging Undergraduates in a Unique Neuroscience Research Opportunity: A Collaborative Research Experience Between a Primarily Undergraduate Institution (PUI) and a Major Research Institution.

    PubMed

    Kreitzer, Matthew A; Malchow, Robert P

    2013-01-01

    This report describes a unique undergraduate research and teaching collaboration between investigators at two institutions, one a relatively small, primarily undergraduate institution and the other a large, urban research-intensive university. The program incorporates three major facets. First, undergraduates participate in a weekly collaborative lab meeting involving instructors from both institutions and held via remote video. Student-led discussions and presentations dominate these meetings, and the unique format promotes novel interactions between students and instructors. Second, students carry out investigative studies centered on understanding the role extracellular pH dynamics play in regulating neuronal processing. Students carry out studies on isolated neurons and glia throughout the fall and spring semesters, and primarily use a noninvasive electrophysiological technique, termed self-referencing, for extracellular pH measurements. The technique is relatively simple and readily learned and employed by undergraduates, while still being powerful enough to provide novel and meaningful research results. The research component is expanded for several students each summer who are selected to participate in summer research with both PIs and graduate students at the major research institution. Finally results gathered during the year and over the summer are disseminated at institutional symposia, undergraduate neuroscience symposia, national society meetings, and in submitted journal manuscripts. Preliminary observations and findings over three years support the aim of this research experience; to create a productive environment that facilitates deep-level understanding of neurophysiological concepts at the undergraduate level and promotes intellectual development while cultivating an excitement for scientific inquiry in the present and future.

  5. Engaging Undergraduates in a Unique Neuroscience Research Opportunity: A Collaborative Research Experience Between a Primarily Undergraduate Institution (PUI) and a Major Research Institution

    PubMed Central

    Kreitzer, Matthew A.; Malchow, Robert P.

    2013-01-01

    This report describes a unique undergraduate research and teaching collaboration between investigators at two institutions, one a relatively small, primarily undergraduate institution and the other a large, urban research-intensive university. The program incorporates three major facets. First, undergraduates participate in a weekly collaborative lab meeting involving instructors from both institutions and held via remote video. Student-led discussions and presentations dominate these meetings, and the unique format promotes novel interactions between students and instructors. Second, students carry out investigative studies centered on understanding the role extracellular pH dynamics play in regulating neuronal processing. Students carry out studies on isolated neurons and glia throughout the fall and spring semesters, and primarily use a noninvasive electrophysiological technique, termed self-referencing, for extracellular pH measurements. The technique is relatively simple and readily learned and employed by undergraduates, while still being powerful enough to provide novel and meaningful research results. The research component is expanded for several students each summer who are selected to participate in summer research with both PIs and graduate students at the major research institution. Finally results gathered during the year and over the summer are disseminated at institutional symposia, undergraduate neuroscience symposia, national society meetings, and in submitted journal manuscripts. Preliminary observations and findings over three years support the aim of this research experience; to create a productive environment that facilitates deep-level understanding of neurophysiological concepts at the undergraduate level and promotes intellectual development while cultivating an excitement for scientific inquiry in the present and future. PMID:24319396

  6. Gender, Sexual Orientation, and Rape Myth Acceptance: Preliminary Findings From a Sample of Primarily LGBQ-Identified Survey Respondents.

    PubMed

    Schulze, Corina; Koon-Magnin, Sarah

    2017-02-01

    This study is among the first to examine the relationship between sexual orientation and rape myth adherence using a nationwide survey of primarily lesbian, gay, bisexual, and queer (LGBQ) respondents (n = 184). The more established Illinois Rape Myth Acceptance Scale and a modified Male Rape Survey serve as the primary instruments to test both rape myth adherence and instrument-appropriateness. Results suggest that respondents were most likely to support myths that discredit sexual assault allegations or excuse rape as a biological imperative and least likely to support myths related to physical resistance. Consistent with previous work, men exhibited higher levels of rape myth adherence than women. Regarding sexual orientation, respondents who identified as queer consistently exhibited lower levels of rape myth adherence than respondents who identified as gay.

  7. Diffuse large B-cell lymphoma arising primarily at the stoma after bladder reconstruction using ileal conduit.

    PubMed

    Muta, Tsuyoshi; Nakaike, Takashi; Fujisaki, Tomoaki; Shiraishi, Takeshi; Ohshima, Koichi

    2012-01-01

    A 76-year-old man suffered from swelling stoma for several weeks. A biopsy sample revealed the diffuse infiltration of large lymphoid cells which were positive for CD20, bcl-6, and MUM1. The patient was diagnosed with diffuse large B-cell lymphoma, with a non-germinal center B-cell pattern. A whole-body PET-CT scan revealed that the lymphoma was restricted to the stomal site. Bladder reconstruction was undertaken using the ileal conduit: this is the first reported case of lymphoma that developed primarily at the stoma. During the long-term maintenance after bladder reconstruction, clinicians should consider the possibility of lymphoma at the stomal site.

  8. The mec-7 beta-tubulin gene of Caenorhabditis elegans is expressed primarily in the touch receptor neurons.

    PubMed Central

    Hamelin, M; Scott, I M; Way, J C; Culotti, J G

    1992-01-01

    Mutants of the mec-7 beta-tubulin gene of Caenorhabditis elegans lack the large diameter 15-protofilament microtubules normally found only in the set of six touch receptor neurons. Both a mec-7-lacZ reporter gene and affinity-purified anti-mec-7 antibodies were used to show that mec-7 is expressed primarily in the touch neurons. These data are consistent with a possible instructive role for the mec-7 tubulin in determining microtubule protofilament number. The antibodies and the mec-7-lacZ transgene were also used to examine mec-7 expression in mutants affecting the generation, differentiation or maintenance of the touch neurons. Decreased expression was observed in mutants of unc-86 and mec-3, genes that encode transcription factors essential for touch receptor neuron generation and differentiation, respectively. Images PMID:1639062

  9. Multi-Province Listeriosis Outbreak Linked to Contaminated Deli Meat Consumed Primarily in Institutional Settings, Canada, 2008.

    PubMed

    Currie, Andrea; Farber, Jeffrey M; Nadon, Céline; Sharma, Davendra; Whitfield, Yvonne; Gaulin, Colette; Galanis, Eleni; Bekal, Sadjia; Flint, James; Tschetter, Lorelee; Pagotto, Franco; Lee, Brenda; Jamieson, Fred; Badiani, Tina; MacDonald, Diane; Ellis, Andrea; May-Hadford, Jennifer; McCormick, Rachel; Savelli, Carmen; Middleton, Dean; Allen, Vanessa; Tremblay, Francois-William; MacDougall, Laura; Hoang, Linda; Shyng, Sion; Everett, Doug; Chui, Linda; Louie, Marie; Bangura, Helen; Levett, Paul N; Wilkinson, Krista; Wylie, John; Reid, Janet; Major, Brian; Engel, Dave; Douey, Donna; Huszczynski, George; Di Lecci, Joe; Strazds, Judy; Rousseau, Josée; Ma, Kenneth; Isaac, Leah; Sierpinska, Urszula

    2015-08-01

    A multi-province outbreak of listeriosis occurred in Canada from June to November 2008. Fifty-seven persons were infected with 1 of 3 similar outbreak strains defined by pulsed-field gel electrophoresis, and 24 (42%) individuals died. Forty-one (72%) of 57 individuals were residents of long-term care facilities or hospital inpatients during their exposure period. Descriptive epidemiology, product traceback, and detection of the outbreak strains of Listeria monocytogenes in food samples and the plant environment confirmed delicatessen meat manufactured by one establishment and purchased primarily by institutions was the source of the outbreak. The food safety investigation identified a plant environment conducive to the introduction and proliferation of L. monocytogenes and persistently contaminated with Listeria spp. This outbreak demonstrated the need for improved listeriosis surveillance, strict control of L. monocytogenes in establishments producing ready-to-eat foods, and advice to vulnerable populations and institutions serving these populations regarding which high-risk foods to avoid.

  10. Surgery of highly eloquent gliomas primarily assessed as non-resectable: risks and benefits in a cohort study.

    PubMed

    Krieg, Sandro M; Schnurbus, Lea; Shiban, Ehab; Droese, Doris; Obermueller, Thomas; Buchmann, Niels; Gempt, Jens; Meyer, Bernhard; Ringel, Florian

    2013-02-02

    Today, the treatment of choice for high- and low-grade gliomas requires primarily surgical resection to achieve the best survival and quality of life. Nevertheless, many gliomas within highly eloquent cortical regions, e.g., insula, rolandic, and left perisylvian cortex, still do not undergo surgery because of the impending risk of surgery-related deficits at some centers. However, pre and intraoperative brain mapping, intraoperative neuromonitoring (IOM), and awake surgery increase safety, which allows resection of most of these tumors with a considerably low rate of postoperatively new deficits. Between 2006 and 2012, we resected 47 out of 51 supratentorial gliomas (92%), which were primarily evaluated to be non-resectable during previous presentation at another neurosurgical department. Out of these, 25 were glioblastomas WHO grade IV (53%), 14 were anaplastic astrocytomas WHO grade III (30%), 7 were diffuse astrocytomas WHO grade II (15%), and one was a pilocytic astrocytoma WHO grade I (2%). All data, including pre and intraoperative brain mapping and monitoring (IOM) by motor evoked potentials (MEPs) were reviewed and related to the postoperative outcome. Awake surgery was performed in 8 cases (17%). IOM was required in 38 cases (81%) and was stable in 18 cases (47%), whereas MEPs changed the surgical strategy in 10 cases (26%). Thereby, gross total resection was achieved in 35 cases (74%). Postoperatively, 17 of 47 patients (36%) had a new motor or language deficit, which remained permanent in 8.5% (4 patients). Progression-free follow-up was 11.3 months (range: 2 weeks - 64.5 months) and median survival was 14.8 months (range: 4 weeks - 20.5 months). Median Karnofsky Performance Scale was 85 before and 80 after surgery). In specialized centers, most highly eloquent gliomas are eligible for surgical resection with an acceptable rate of surgery-related deficits; therefore, they should be referred to specialized centers.

  11. Healthy younger and older adults control foot placement to avoid small obstacles during gait primarily by modulating step width.

    PubMed

    Schulz, Brian W

    2012-10-03

    Falls are a significant problem in the older population. Most falls occur during gait, which is primarily regulated by foot placement. Variability of foot placement has been associated with falls, but these associations are inconsistent and generally for smooth, level flooring. This study investigates the control of foot placement and the associated gait variability in younger and older men and women (N=7/group, total N=28) while walking at three different speeds (slow, preferred, and fast) across a control surface with no obstacles and surfaces with multiple (64) small (10 cm long ×13 mm high) visible and hidden obstacles. Minimum obstacle distance between the shoe and nearest obstacle during each footfall was greater on the visible obstacles surface for older subjects because some of them chose to actively avoid obstacles. This obstacle avoidance strategy was implemented primarily by modulating step width and to a lesser extent step length as indicated by linear regressions of step width and length variability on minimum obstacle distance. Mean gait speed, step length, step width, and step time did not significantly differ by subject group, flooring surface, or obstacle avoidance strategy. Some healthy older subjects choose to actively avoid small obstacles that do not substantially perturb their gait by modulating step width and, to a lesser extent, step length. It is not clear if this obstacle avoidance strategy is appropriate and beneficial or overcautious and maladaptive, as it results in fewer obstacles encountered at a consequence of a less efficient gait pattern that has been shown to indicate increased fall risk. Further research is needed on the appropriateness of strategy selection when the environmental demands and/or task requirements have multiple possible completion strategies with conflicting objectives (i.e. perceived safety vs. efficiency).

  12. Development and Sensitivity Analysis of a Frost Risk model based primarily on freely distributed Earth Observation data

    NASA Astrophysics Data System (ADS)

    Louka, Panagiota; Petropoulos, George; Papanikolaou, Ioannis

    2015-04-01

    The ability to map the spatiotemporal distribution of extreme climatic conditions, such as frost, is a significant tool in successful agricultural management and decision making. Nowadays, with the development of Earth Observation (EO) technology, it is possible to obtain accurately, timely and in a cost-effective way information on the spatiotemporal distribution of frost conditions, particularly over large and otherwise inaccessible areas. The present study aimed at developing and evaluating a frost risk prediction model, exploiting primarily EO data from MODIS and ASTER sensors and ancillary ground observation data. For the evaluation of our model, a region in north-western Greece was selected as test site and a detailed sensitivity analysis was implemented. The agreement between the model predictions and the observed (remotely sensed) frost frequency obtained by MODIS sensor was evaluated thoroughly. Also, detailed comparisons of the model predictions were performed against reference frost ground observations acquired from the Greek Agricultural Insurance Organization (ELGA) over a period of 10-years (2000-2010). Overall, results evidenced the ability of the model to produce reasonably well the frost conditions, following largely explainable patterns in respect to the study site and local weather conditions characteristics. Implementation of our proposed frost risk model is based primarily on satellite imagery analysis provided nowadays globally at no cost. It is also straightforward and computationally inexpensive, requiring much less effort in comparison for example to field surveying. Finally, the method is adjustable to be potentially integrated with other high resolution data available from both commercial and non-commercial vendors. Keywords: Sensitivity analysis, frost risk mapping, GIS, remote sensing, MODIS, Greece

  13. Y-chromosomal analysis of Greek Cypriots reveals a primarily common pre-Ottoman paternal ancestry with Turkish Cypriots.

    PubMed

    Heraclides, Alexandros; Bashiardes, Evy; Fernández-Domínguez, Eva; Bertoncini, Stefania; Chimonas, Marios; Christofi, Vasilis; King, Jonathan; Budowle, Bruce; Manoli, Panayiotis; Cariolou, Marios A

    2017-01-01

    Genetics can provide invaluable information on the ancestry of the current inhabitants of Cyprus. A Y-chromosome analysis was performed to (i) determine paternal ancestry among the Greek Cypriot (GCy) community in the context of the Central and Eastern Mediterranean and the Near East; and (ii) identify genetic similarities and differences between Greek Cypriots (GCy) and Turkish Cypriots (TCy). Our haplotype-based analysis has revealed that GCy and TCy patrilineages derive primarily from a single gene pool and show very close genetic affinity (low genetic differentiation) to Calabrian Italian and Lebanese patrilineages. In terms of more recent (past millennium) ancestry, as indicated by Y-haplotype sharing, GCy and TCy share much more haplotypes between them than with any surrounding population (7-8% of total haplotypes shared), while TCy also share around 3% of haplotypes with mainland Turks, and to a lesser extent with North Africans. In terms of Y-haplogroup frequencies, again GCy and TCy show very similar distributions, with the predominant haplogroups in both being J2a-M410, E-M78, and G2-P287. Overall, GCy also have a similar Y-haplogroup distribution to non-Turkic Anatolian and Southwest Caucasian populations, as well as Cretan Greeks. TCy show a slight shift towards Turkish populations, due to the presence of Eastern Eurasian (some of which of possible Ottoman origin) Y-haplogroups. Overall, the Y-chromosome analysis performed, using both Y-STR haplotype and binary Y-haplogroup data puts Cypriot in the middle of a genetic continuum stretching from the Levant to Southeast Europe and reveals that despite some differences in haplotype sharing and haplogroup structure, Greek Cypriots and Turkish Cypriots share primarily a common pre-Ottoman paternal ancestry.

  14. Y-chromosomal analysis of Greek Cypriots reveals a primarily common pre-Ottoman paternal ancestry with Turkish Cypriots

    PubMed Central

    Fernández-Domínguez, Eva; Bertoncini, Stefania; Chimonas, Marios; Christofi, Vasilis; King, Jonathan; Budowle, Bruce; Manoli, Panayiotis

    2017-01-01

    Genetics can provide invaluable information on the ancestry of the current inhabitants of Cyprus. A Y-chromosome analysis was performed to (i) determine paternal ancestry among the Greek Cypriot (GCy) community in the context of the Central and Eastern Mediterranean and the Near East; and (ii) identify genetic similarities and differences between Greek Cypriots (GCy) and Turkish Cypriots (TCy). Our haplotype-based analysis has revealed that GCy and TCy patrilineages derive primarily from a single gene pool and show very close genetic affinity (low genetic differentiation) to Calabrian Italian and Lebanese patrilineages. In terms of more recent (past millennium) ancestry, as indicated by Y-haplotype sharing, GCy and TCy share much more haplotypes between them than with any surrounding population (7–8% of total haplotypes shared), while TCy also share around 3% of haplotypes with mainland Turks, and to a lesser extent with North Africans. In terms of Y-haplogroup frequencies, again GCy and TCy show very similar distributions, with the predominant haplogroups in both being J2a-M410, E-M78, and G2-P287. Overall, GCy also have a similar Y-haplogroup distribution to non-Turkic Anatolian and Southwest Caucasian populations, as well as Cretan Greeks. TCy show a slight shift towards Turkish populations, due to the presence of Eastern Eurasian (some of which of possible Ottoman origin) Y-haplogroups. Overall, the Y-chromosome analysis performed, using both Y-STR haplotype and binary Y-haplogroup data puts Cypriot in the middle of a genetic continuum stretching from the Levant to Southeast Europe and reveals that despite some differences in haplotype sharing and haplogroup structure, Greek Cypriots and Turkish Cypriots share primarily a common pre-Ottoman paternal ancestry. PMID:28622394

  15. Model-independent analyses of dark-matter particle interactions

    SciTech Connect

    Anand, Nikhil; Fitzpatrick, A. Liam; Haxton, W. C.

    2015-03-24

    A model-independent treatment of dark-matter particle elastic scattering has been developed, yielding the most general interaction for WIMP-nucleon low-energy scattering, and the resulting amplitude has been embedded into the nucleus, taking into account the selection rules imposed by parity and time-reversal. One finds that, in contrast to the usual spin-independent/spin-dependent (SI/SD) formulation, the resulting cross section contains six independent nuclear response functions, three of which are associated with possible velocity-dependent interactions. We find that current experiments are four orders of magnitude more sensitive to derivative couplings than is apparent in the standard SI/SD treatment, which necessarily associated such interactions with cross sections proportional to v2T ~ 10⁻⁶, where vT is the WIMP velocity relative to the center of mass of the nuclear target.

  16. Magnetic phases of spin-1 lattice gases with random interactions

    NASA Astrophysics Data System (ADS)

    McAlpine, Kenneth D.; Paganelli, Simone; Ciuchi, Sergio; Sanpera, Anna; De Chiara, Gabriele

    2017-06-01

    A spin-1 atomic gas in an optical lattice, in the unit-filling Mott insulator (MI) phase and in the presence of disordered spin-dependent interaction, is considered. In this regime, at zero temperature, the system is well described by a disordered rotationally invariant spin-1 bilinear-biquadratic model. We study, via the density matrix renormalization group algorithm, a bounded disorder model such that the spin interactions can be locally either ferromagnetic or antiferromagnetic. Random interactions induce the appearance of a disordered ferromagnetic phase characterized by a nonvanishing value of the spin glass order parameter across the boundary between a ferromagnetic phase and a dimer phase exhibiting random singlet order. We also study the distribution of the block entanglement entropy in the different regions.

  17. Model-independent analyses of dark-matter particle interactions

    DOE PAGES

    Anand, Nikhil; Fitzpatrick, A. Liam; Haxton, W. C.

    2015-03-24

    A model-independent treatment of dark-matter particle elastic scattering has been developed, yielding the most general interaction for WIMP-nucleon low-energy scattering, and the resulting amplitude has been embedded into the nucleus, taking into account the selection rules imposed by parity and time-reversal. One finds that, in contrast to the usual spin-independent/spin-dependent (SI/SD) formulation, the resulting cross section contains six independent nuclear response functions, three of which are associated with possible velocity-dependent interactions. We find that current experiments are four orders of magnitude more sensitive to derivative couplings than is apparent in the standard SI/SD treatment, which necessarily associated such interactions withmore » cross sections proportional to v2T ~ 10⁻⁶, where vT is the WIMP velocity relative to the center of mass of the nuclear target.« less

  18. Imitation, Interaction and Dialogue Using Intensive Interaction: Tea Party Rules

    ERIC Educational Resources Information Center

    Barber, Mark

    2007-01-01

    Intensive Interaction has become widely used when building up communication with children with profound learning difficulties. Often practitioners understand Intensive Interaction to be primarily about imitation and Mark Barber shows how this can be a "mis"understanding that limits the kinds of interactions that can be enjoyed by conversation…

  19. Potential of the neutron lloyd's mirror interferometer for the search for new interactions

    SciTech Connect

    Pokotilovski, Yu. N.

    2013-04-15

    We discuss the potential of the neutron Lloyd's mirror interferometer in a search for new interactions at small scales. We consider three hypothetical interactions that may be tested using the interferometer. The chameleon scalar field proposed to solve the enigma of accelerating expansion of the Universe produces interaction between particles and matter. The axion-like spin-dependent coupling between a neutron and nuclei or/and electrons may result in a P- and T-noninvariant interaction with matter. Hypothetical non-Newtonian gravitational interactions mediates an additional short-range potential between neutrons and bulk matter. These interactions between the neutron and the mirror of a Lloyd-type neutron interferometer cause a phase shift of neutron waves. We estimate the sensitivity and systematic effects of possible experiments.

  20. Negative effects on survival and performance of Norway spruce seedlings colonized by dark septate root endophytes are primarily isolate-dependent.

    PubMed

    Tellenbach, Christoph; Grünig, Christoph R; Sieber, Thomas N

    2011-09-01

    Root endophytes are common and genetically highly diverse suggesting important ecological roles. Yet, relative to above-ground endophytes, little is known about them. Dark septate endophytic fungi of the Phialocephala fortinii s.l.-Acephala applanata species complex (PAC) are ubiquitous root colonizers of conifers and Ericaceae, but their ecological function is largely unknown. Responses of Norway spruce seedlings of two seed provenances to inoculations with isolates of four PAC species were studied in vitro. In addition, isolates of Phialocephala subalpina from two populations within and one outside the natural range of Norway spruce were also included to study the effect of the geographic origin of P. subalpina on host response. The interaction of PAC with Norway spruce ranged from neutral to highly virulent and was primarily isolate-dependent. Variation in virulence was much higher within than among species, nonetheless only isolates of P. subalpina were highly virulent. Disease caused by P. subalpina genotypes from the native range of Norway spruce was more severe than that induced by genotypes from outside the natural distribution of Norway spruce. Virulence was not correlated with the phylogenetic relatedness of the isolates but was positively correlated with the extent of fungal colonization as measured by quantitative real-time PCR.

  1. Inverted Papilloma Originating Primarily from the Nasolacrimal Duct: A Case Report and Review of the Pertinent Literature

    PubMed Central

    Walijee, Hussein Z.; Berry, Sandeep; Quine, Stuart; Lane, Carol; Morris, Daniel S.; Bowman, Benedict

    2015-01-01

    Introduction. Inverted papilloma (IP) is an uncommon, benign yet aggressive neoplasm characterised by high recurrence rates and tendency towards malignant transformation. The majority of IP cases originate in the ethmoid region, lateral wall of the nasal fossa, and maxillary sinus. The authors report a case of an IP originating primarily from the nasolacrimal duct (NLD). Case. A 69-year-old Caucasian gentleman presented with a lump in his right medial canthal region, epiphora, and discharge bilaterally. Radiological investigation revealed a well-defined, heterogeneous mass within the proximal NLD eroding the bony canal, protruding into the middle meatus and into the right orbit. The tumour was excised en bloc utilizing a combined external and endoscopic approach based on its location. Histology revealed hyperplastic ribbons of basement membrane-enclosed epithelium growing endophytically into the underlying stroma with no evidence of invasive malignancy. The patient made an uneventful recovery with unchanged visual acuity and normal extraocular movements. Conclusion. The case demonstrates variability within the sinonasal tract that IP can develop and the individuality of each case necessitating tailored operative techniques for complete excision whilst minimising recurrence rates. We also present a combined endoscopic approach for the en bloc resection of a NLD IP with no clinical recurrence at 15-month follow-up. PMID:26649215

  2. Inverted Papilloma Originating Primarily from the Nasolacrimal Duct: A Case Report and Review of the Pertinent Literature.

    PubMed

    Walijee, Hussein Z; Berry, Sandeep; Quine, Stuart; Lane, Carol; Morris, Daniel S; Bowman, Benedict

    2015-01-01

    Introduction. Inverted papilloma (IP) is an uncommon, benign yet aggressive neoplasm characterised by high recurrence rates and tendency towards malignant transformation. The majority of IP cases originate in the ethmoid region, lateral wall of the nasal fossa, and maxillary sinus. The authors report a case of an IP originating primarily from the nasolacrimal duct (NLD). Case. A 69-year-old Caucasian gentleman presented with a lump in his right medial canthal region, epiphora, and discharge bilaterally. Radiological investigation revealed a well-defined, heterogeneous mass within the proximal NLD eroding the bony canal, protruding into the middle meatus and into the right orbit. The tumour was excised en bloc utilizing a combined external and endoscopic approach based on its location. Histology revealed hyperplastic ribbons of basement membrane-enclosed epithelium growing endophytically into the underlying stroma with no evidence of invasive malignancy. The patient made an uneventful recovery with unchanged visual acuity and normal extraocular movements. Conclusion. The case demonstrates variability within the sinonasal tract that IP can develop and the individuality of each case necessitating tailored operative techniques for complete excision whilst minimising recurrence rates. We also present a combined endoscopic approach for the en bloc resection of a NLD IP with no clinical recurrence at 15-month follow-up.

  3. Human land uses enhance sediment denitrification and N2O production in Yangtze lakes primarily by influencing lake water quality

    NASA Astrophysics Data System (ADS)

    Liu, W.; Yao, L.; Wang, Z.; Xiong, Z.; Liu, G.

    2015-10-01

    Sediment denitrification in lakes alleviates the effects of eutrophication through the removal of nitrogen to the atmosphere as N2O and N2. However, N2O contributes notably to the greenhouse effect and global warming. Human land uses (e.g. agricultural and urban areas) strongly affect lake water quality and sediment characteristics, which, in turn, may regulate lake sediment denitrification and N2O production. In this study, we investigated sediment denitrification and N2O production and their relationships to within-lake variables and watershed land uses in 20 lakes from the Yangtze River basin in China. The results indicated that both lake water quality and sediment characteristics were significantly influenced by watershed land uses. N2O production rates increased with increasing background denitrification rates. Background denitrification and N2O production rates were positively related to water nitrogen concentrations but were not significantly correlated with sediment characteristics and plant community structure. A significant positive relationship was observed between background denitrification rate and percentage of human-dominated land uses (HDL) in watersheds. Structural equation modelling revealed that the indirect effects of HDL on sediment denitrification and N2O production in Yangtze lakes were mediated primarily through lake water quality. Our findings also suggest that although sediments in Yangtze lakes can remove large quantities of nitrogen through denitrification, they may also be an important source of N2O, especially in lakes with high nitrogen content.

  4. Adolescent Pornography Use and Dating Violence among a Sample of Primarily Black and Hispanic, Urban-Residing, Underage Youth.

    PubMed

    Rothman, Emily F; Adhia, Avanti

    2015-12-23

    This cross-sectional study was designed to characterize the pornography viewing preferences of a sample of U.S.-based, urban-residing, economically disadvantaged, primarily Black and Hispanic youth (n = 72), and to assess whether pornography use was associated with experiences of adolescent dating abuse (ADA) victimization. The sample was recruited from a large, urban, safety net hospital, and participants were 53% female, 59% Black, 19% Hispanic, 14% Other race, 6% White, and 1% Native American. All were 16-17 years old. More than half (51%) had been asked to watch pornography together by a dating or sexual partner, and 44% had been asked to do something sexual that a partner saw in pornography. Adolescent dating abuse (ADA) victimization was associated with more frequent pornography use, viewing pornography in the company of others, being asked to perform a sexual act that a partner first saw in pornography, and watching pornography during or after marijuana use. Approximately 50% of ADA victims and 32% of non-victims reported that they had been asked to do a sexual act that their partner saw in pornography (p = 0.15), and 58% did not feel happy to have been asked. Results suggest that weekly pornography use among underage, urban-residing youth may be common, and may be associated with ADA victimization.

  5. Bimanual cross-talk during reaching movements is primarily related to response selection, not the specification of motor parameters

    NASA Technical Reports Server (NTRS)

    Hazeltine, Eliot; Diedrichsen, Joern; Kennerley, Steven W.; Ivry, Richard B.

    2003-01-01

    Simultaneous reaching movements made with the two hands can show a considerable increase in reaction time (RT) when they differ in terms of direction or extent, compared to when the movements involve the same direction and extent. This cost has been attributed to cross-talk in the specification of the motor parameters for the two hands. However, a recent study [Diedrichsen, Hazeltine, Kennerley, & Ivry, (2001). Psychological Science, 12, 493-498] indicates that when reaching movements are cued by the onset of the target endpoint, no compatibility effects are observed. To determine why directly cued movements are immune from interference, we varied the stimulus onset asynchrony for the two movements and used different combinations of directly cued and symbolically cued movements. In two experiments, compatibility effects were only observed when both movements were symbolically cued. No difference was found between compatible and incompatible movements when both movements were directly cued or when one was directly cued and the other was symbolically cued. These results indicate that interference is not related to the specification of movement parameters but instead emerges from processes associated with response selection. Moreover, the data suggest that cross-talk, when present, primarily shortens the RT of the second movement on compatible trials rather than lengthening this RT on incompatible trials.

  6. Chemical and biological studies of a new cigarette that primarily heats tobacco. Part 1. Chemical composition of mainstream smoke.

    PubMed

    Borgerding, M F; Bodnar, J A; Chung, H L; Mangan, P P; Morrison, C C; Risner, C H; Rogers, J C; Simmons, D F; Uhrig, M S; Wendelboe, F N; Wingate, D E; Winkler, L S

    1998-03-01

    A new-technology cigarette has been developed. While the new cigarette burns some tobacco, it does not use tobacco as the fuel to sustain combustion and provide heat to the cigarette. Rather, the new cigarette primarily heats tobacco thereby reducing products of smoke formation mechanisms such as tobacco combustion, tobacco pyrolysis and pyrosynthesis. The mainstream smoke composition from a cigarette based on the new design (TOB-HT) has been characterized in comparative chemical testing with two reference cigarettes using the FTC puffing regimen. Thermal properties, UV absorption characteristics, elemental composition and materials balance studies all suggest a simplified smoke aerosol. Twenty-five smoke constituents ("target compounds") identified by the scientific community as compounds that may contribute to the diseases statistically associated with smoking have also been measured. Mainstream smoke concentrations of most target compounds are significantly lower with the TOB-HT cigarette when compared with reference cigarettes in the ultra-light "tar" and light "tar" categories. Taken together, chemical analysis results suggest simplified TOB-HT smoke chemistry with marked reductions in specific chemicals reported to be biologically active.

  7. Chemical and biological studies of a new cigarette that primarily heats tobacco. Part 1. Chemical composition of mainstream smoke.

    PubMed

    Borgerding, M F; Bodnar, J A; Chung, H L; Mangan, P P; Morrison, C C; Risner, C H; Rogers, J C; Simmons, D F; Uhrig, M S; Wendelboe, F N; Wingate, D E; Winkler, L S

    1998-07-01

    A new-technology cigarette has been developed. While the new cigarette burns some tobacco, it does not use tobacco as the fuel to sustain combustion and provide heat to the cigarette. Rather, the new cigarette primarily heats tobacco thereby reducing products of smoke formation mechanisms such as tobacco combustion, tobacco pyrolysis and pyrosynthesis. The mainstream smoke composition from a cigarette based on the new design (TOB-HT) has been characterized in comparative chemical testing with two reference cigarettes using the FTC puffing regimen. Thermal properties, UV absorption characteristics, elemental composition and materials balance studies all suggest a simplified smoke aerosol. Twenty-five smoke constituents ("target compounds") identified by the scientific community as compounds that may contribute to the diseases statistically associated with smoking have also been measured. Mainstream smoke concentrations of most target compounds are significantly lower with the TOB-HT cigarette when compared with reference cigarettes in the ultra-light "tar" and light "tar" categories. Taken together, chemical analysis results suggest simplified TOB-HT smoke chemistry with marked reductions in specific chemicals reported to be biologically active.

  8. Patient-Provider Engagement and Chronic Pain in Drug-Using, Primarily African American Persons Living with HIV/AIDS.

    PubMed

    Mitchell, Mary M; Nguyen, Trang Q; Maragh-Bass, Allysha C; Isenberg, Sarina R; Beach, Mary Catherine; Knowlton, Amy R

    2016-10-27

    Among disadvantaged persons living with HIV/AIDS (PLHIV), patient-provider engagement, which has been defined as patient-provider relationships that promote the use of health care services and are characterized by active listening and supportive decision making, has been associated with antiretroviral therapy (ART) maintenance and viral suppression. However, chronic pain, depression, and substance use, all of which are prevalent in this population, can reduce the quality of patient-provider engagement. We hypothesized a model in which chronic pain, depression, and substance use would be associated with poorer patient-provider engagement, which would be positively associated with adherence, with the latter associated positively with viral suppression. We analyzed data from the BEACON study, which included surveys from 383 PLHIV who were primarily African American, on ART, and had histories of drug use. Due to six missing cases on the chronic pain variable, we used data from 377 respondents in a structural equation model. Chronic pain and depressive symptoms were significantly associated with poorer patient-provider engagement, while substance use was associated with better engagement. Patient-provider engagement in turn was associated with better ART adherence, which was associated with higher viral suppression. Results suggest the role of chronic pain in poor patient-physician engagement in this population, which has potential implications for quality of HIV patient care and health outcomes. Findings suggest the need for attention to patient-provider engagement in PLHIV.

  9. Bimanual cross-talk during reaching movements is primarily related to response selection, not the specification of motor parameters

    NASA Technical Reports Server (NTRS)

    Hazeltine, Eliot; Diedrichsen, Joern; Kennerley, Steven W.; Ivry, Richard B.

    2003-01-01

    Simultaneous reaching movements made with the two hands can show a considerable increase in reaction time (RT) when they differ in terms of direction or extent, compared to when the movements involve the same direction and extent. This cost has been attributed to cross-talk in the specification of the motor parameters for the two hands. However, a recent study [Diedrichsen, Hazeltine, Kennerley, & Ivry, (2001). Psychological Science, 12, 493-498] indicates that when reaching movements are cued by the onset of the target endpoint, no compatibility effects are observed. To determine why directly cued movements are immune from interference, we varied the stimulus onset asynchrony for the two movements and used different combinations of directly cued and symbolically cued movements. In two experiments, compatibility effects were only observed when both movements were symbolically cued. No difference was found between compatible and incompatible movements when both movements were directly cued or when one was directly cued and the other was symbolically cued. These results indicate that interference is not related to the specification of movement parameters but instead emerges from processes associated with response selection. Moreover, the data suggest that cross-talk, when present, primarily shortens the RT of the second movement on compatible trials rather than lengthening this RT on incompatible trials.

  10. Predictors of moderated drinking in a primarily alcohol dependent sample of men who have sex with men

    PubMed Central

    Kuerbis, Alexis; Morgenstern, Jon; Hail, Lisa

    2012-01-01

    Understanding for whom moderated drinking is a viable, achievable, and sustainable goal among those with a range of alcohol use disorders (AUD) remains an important public health question. Despite common acceptance as severe risk factors, there is little empirical evidence to conclude whether co-occurring mental health disorders or drug dependence contribute to an individual’s inability to successfully moderate his drinking. Utilizing secondary data analysis, the purpose of this study was to identify predictors of moderation among both treatment seeking and non-treatment seeking, primarily alcohol dependent, problem drinking men who have sex with men (MSM), with an emphasis on the high risk factors psychiatric comorbidity and drug dependence. Problem drinkers (N=187) were assessed, provided feedback about their drinking, given the option to receive brief AUD treatment or change their drinking on their own, and then followed for 15 months. Findings revealed that neither psychiatric comorbidity or drug dependence predicted ability to achieve moderation when controlling for alcohol dependence severity. Those who were younger, more highly educated, and had more mild alcohol dependence were more likely to achieve moderated drinking. Impact of treatment on predictors is explored. Limitations of this study and arenas for future research are discussed. PMID:22201219

  11. Predictors of moderated drinking in a primarily alcohol-dependent sample of men who have sex with men.

    PubMed

    Kuerbis, Alexis; Morgenstern, Jon; Hail, Lisa

    2012-09-01

    Understanding for whom moderated drinking is a viable, achievable, and sustainable goal among those with a range of alcohol use disorders (AUD) remains an important public health question. Despite common acceptance as severe risk factors, there is little empirical evidence to conclude whether co-occurring mental health disorders or drug dependence contribute to an individual's inability to successfully moderate his drinking. Utilizing secondary data analysis, the purpose of this study was to identify predictors of moderation among both treatment-seeking and non-treatment-seeking, primarily alcohol-dependent, problem-drinking men who have sex with men (MSM), with an emphasis on the high risk factors psychiatric comorbidity and drug dependence. Problem drinkers (N=187) were assessed, provided feedback about their drinking, given the option to receive brief AUD treatment or change their drinking on their own, and then followed for 15 months. Findings revealed that neither psychiatric comorbidity or drug dependence predicted ability to achieve moderation when controlling for alcohol dependence severity. Those who were younger, more highly educated, and had more mild alcohol dependence were more likely to achieve moderated drinking. Impact of treatment on predictors is explored. Limitations of this study and arenas for future research are discussed. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  12. Adolescent Pornography Use and Dating Violence among a Sample of Primarily Black and Hispanic, Urban-Residing, Underage Youth

    PubMed Central

    Rothman, Emily F.; Adhia, Avanti

    2015-01-01

    This cross-sectional study was designed to characterize the pornography viewing preferences of a sample of U.S.-based, urban-residing, economically disadvantaged, primarily Black and Hispanic youth (n = 72), and to assess whether pornography use was associated with experiences of adolescent dating abuse (ADA) victimization. The sample was recruited from a large, urban, safety net hospital, and participants were 53% female, 59% Black, 19% Hispanic, 14% Other race, 6% White, and 1% Native American. All were 16–17 years old. More than half (51%) had been asked to watch pornography together by a dating or sexual partner, and 44% had been asked to do something sexual that a partner saw in pornography. Adolescent dating abuse (ADA) victimization was associated with more frequent pornography use, viewing pornography in the company of others, being asked to perform a sexual act that a partner first saw in pornography, and watching pornography during or after marijuana use. Approximately 50% of ADA victims and 32% of non-victims reported that they had been asked to do a sexual act that their partner saw in pornography (p = 0.15), and 58% did not feel happy to have been asked. Results suggest that weekly pornography use among underage, urban-residing youth may be common, and may be associated with ADA victimization. PMID:26703744

  13. Skyrme-Landau parameterization of effective interactions (II). Self-consistent description of giant multipole resonances

    NASA Astrophysics Data System (ADS)

    Liu, Keh-Fei; Luo, Hongde; Ma, Zhongyu; Shen, Qingbiao

    1991-11-01

    The positions and the transition strengths of giant multipole resonances (including electric, magnetic, Fermi and Gamow-Teller transitions of the spherical nuclei 16O, 40Ca, 48Ca, 90Zr, 208Pb) are calculated using the random phase approximation based on the Hartree-Fock ground states with our new extended Skyrme-Landau interaction - SL1. The method of calculating Green function in coordinate space is extended to included spin dependence; this makes it possible to calculate M1 and Gamow-Teller transitions. The predicted resonance positions agree well with the experimental results. The Thouless sum rules are checked to within 10-15% in most cases.

  14. Ab Initio Electronic Structure Calculations of Cytochrome P450 -- Ligand Interactions

    NASA Astrophysics Data System (ADS)

    Segall, M. D.; Payne, M. C.; Ellis, S. W.; Tucker, G. T.

    1997-03-01

    The Cytochrome P450 superfamily of enzymes are of great interest in pharmacology as they participate in an enormous range of physiological processes including drug deactivation and xenobiotic detoxification. We apply ab initio electronic structure calculations to model the interactions of the haem molecule at the P450 active site with substrate and inhibitor ligands. These calculations, based on density function theory, were performed with the CETEP code which uses a plane wave basis set and pseudopotentials to perform efficient LDA, GGA and spin dependent calculations. A change in the spin state of the haem iron atom is observed on binding of a substrate molecule, consistent with the accepted reaction mechanism.

  15. Mouse lysine catabolism to aminoadipate occurs primarily through the saccharopine pathway; implications for pyridoxine dependent epilepsy (PDE).

    PubMed

    Pena, Izabella Agostinho; Marques, Lygia Azevedo; Laranjeira, Ângelo B A; Yunes, José A; Eberlin, Marcos N; MacKenzie, Alex; Arruda, Paulo

    2017-01-01

    Lysine is catabolized in mammals through the saccharopine and pipecolate pathways - the former is mainly hepatic and renal, and the latter is believed to play a role in the cerebral lysine oxidation. Both pathways lead to the formation of aminoadipic semialdehyde (AASA) that is then oxidized to aminoadipate (AAA) by antiquitin (ALDH7A1). Mutations in the ALDH7A1 gene result in the accumulation of AASA and its cyclic form, piperideine-6-carboxylate (P6C), which causes pyridoxine-dependent epilepsy (PDE). P6C reacts with pyridoxal 5'-phosphate (PLP) causing its inactivation. Here, we used liquid chromatography-mass spectrometry to investigate lysine catabolism in mice injected with lysine labelled at either its nitrogen epsilon (ε-(15)N) or nitrogen alpha (α-(15)N). Analysis of ε-(15)N and α-(15)N lysine catabolites in plasma, liver and brain suggested the saccharopine as the main pathway for AAA biosynthesis. Although there was evidence for upstream cerebral pipecolate pathway activity, the resulting pipecolate does not appear to be further oxidized into AASA/P6C/AAA. By far the bulk of lysine degradation and therefore, the primary source of lysine catabolites are hepatic and renal. The results indicate that the saccharopine pathway is primarily responsible for body's production of AASA/P6C. The centrality of the saccharopine pathway in whole body lysine catabolism opens new possibilities of therapeutic targets for PDE. We suggest that inhibition of this pathway upstream of AASA/P6C synthesis may be used to prevent its accumulation benefiting PDE patients. Inhibition of the enzyme aminoadipic semialdehyde synthase, for example, could constitute a new strategy to treat PDE and other inherited diseases of lysine catabolism.

  16. Transient activation of microglia following acute alcohol exposure in developing mouse neocortex is primarily driven by BAX-dependent neurodegeneration.

    PubMed

    Ahlers, Katelin E; Karaçay, Bahri; Fuller, Leah; Bonthius, Daniel J; Dailey, Michael E

    2015-10-01

    Fetal alcohol exposure is the most common known cause of preventable mental retardation, yet we know little about how microglia respond to, or are affected by, alcohol in the developing brain in vivo. Using an acute (single day) model of moderate (3 g/kg) to severe (5 g/kg) alcohol exposure in postnatal day (P) 7 or P8 mice, we found that alcohol-induced neuroapoptosis in the neocortex is closely correlated in space and time with the appearance of activated microglia near dead cells. The timing and molecular pattern of microglial activation varied with the level of cell death. Although microglia rapidly mobilized to contact and engulf late-stage apoptotic neurons, apoptotic bodies temporarily accumulated in neocortex, suggesting that in severe cases of alcohol toxicity the neurodegeneration rate exceeds the clearance capacity of endogenous microglia. Nevertheless, most dead cells were cleared and microglia began to deactivate within 1-2 days of the initial insult. Coincident with microglial activation and deactivation, there was a transient increase in expression of pro-inflammatory factors, TNFα and IL-1β, after severe (5 g/kg) but not moderate (3 g/kg) EtOH levels. Alcohol-induced microglial activation and pro-inflammatory factor expression were largely abolished in BAX null mice lacking neuroapoptosis, indicating that microglial activation is primarily triggered by apoptosis rather than the alcohol. Therefore, acute alcohol exposure in the developing neocortex causes transient microglial activation and mobilization, promoting clearance of dead cells and tissue recovery. Moreover, cortical microglia show a remarkable capacity to rapidly deactivate following even severe neurodegenerative insults in the developing brain.

  17. Social Media Use and its Association with Sexual Risk and Parental Monitoring among a Primarily Hispanic Adolescent Population.

    PubMed

    Romo, Dina L; Garnett, Chelsea; Younger, Alayna P; Stockwell, Melissa S; Soren, Karen; Catallozzi, Marina; Neu, Natalie

    2017-08-01

    In this study we assessed the association between social media (SM) use with sexual risk, and with parental monitoring among Hispanic adolescents. Self-administered anonymous survey. Urban primary care clinics. Primarily Hispanic adolescents ages 13-21 years old. Chi-square and regression analyses controlling for age and gender were used to assess associations between SM use or sexting and sexual behaviors (kissing, touching genitals, vaginal oral, and anal sex), sexual risk (≥4 lifetime partners, >1 recent partner, inconsistent condom use, and history of sexually transmitted infection diagnosis) and contraceptive use. Similar analyses were used to assess relationships between adolescent-reported parental monitoring and SM use, and sexting. Participants with frequent SM use (social networking sites or apps) had greater odds of all sexual activity. Ever sexters had greater odds of penetrative sex only (oral, vaginal, and anal sex) as well as use of hormonal contraception (except long-acting reversible contraception). Approximately half of the participants reported parental access to profiles on SM. Female participants had higher odds of parental access to online profiles and having a parental discussion of privacy settings. Those having privacy discussions had greater odds of "private" profiles on SM and lower odds of ever sexting. Frequent SM use and sexting was associated with an increase in all types of sexual behaviors; sexting alone was associated with more lifetime and recent sexual partners. Parental discussion of privacy settings was found to be protective. Providers and parents should be aware of the effect of SM use on sexual behaviors. Copyright © 2017 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

  18. Evaluation of Worker's Living Activity-time Questionnaire (JNIOSH-WLAQ) primarily to assess workers' sedentary behavior.

    PubMed

    Matsuo, Tomoaki; So, Rina; Sasai, Hiroyuki; Ohkawara, Kazunori

    2017-09-26

    The National Institute of Occupational Safety and Health, Japan (JNIOSH) developed a new Worker's Living Activity-time Questionnaire (JNIOSH-WLAQ) which primarily evaluates workers' sedentary behavior. The purpose of this study was to investigate the test-retest reliability and criterion validity of the WLAQ. One hundred and thirty eight workers completed the WLAQ twice in one week. During the week, they wore a thigh-worn inclinometer (activPAL) and maintained a daily log as criteria measurements. The WLAQ measures working time, commuting time, daily rest period (DRP), sleeping time, and time spent sitting within the four typical domains of a worker's life: (a) working time, (b) commuting time, (c) non-working time on a workday, and (d) non-workday. We calculated intraclass correlation coefficients (ICC) as a reliability value and Spearman's ρ as a validity value. Bland-Altman plots were used to assess any bias. The analysis of WLAQ indicated favorable ICCs (0.72-0.98) for all living activity-times. The WLAQ had "strong" ρ values for working time (0.80) and DRP (0.83), a "very strong" ρ value for commuting time (0.96), and "moderate" ρ values for sleeping time during a workday (0.69) and a non-workday (0.53). As for the sitting time, the WLAQ had "moderate" ρ values for working time (0.67) and non-working time on a workday (0.59), a "strong" ρ value for commuting time (0.82), and a "low" ρ value for a non-workday (0.40). Bland-Altman plots showed a significant fixed bias for sitting time during working time and significant fixed and proportional biases for sitting time on a non-workday. The study showed that the WLAQ has acceptable measurement features, which makes this questionnaire a reliable resource for future epidemiological surveys.

  19. Y-Chromosomal Diversity in Europe Is Clinal and Influenced Primarily by Geography, Rather than by Language

    PubMed Central

    Rosser, Zoë H.; Zerjal, Tatiana; Hurles, Matthew E.; Adojaan, Maarja; Alavantic, Dragan; Amorim, António; Amos, William; Armenteros, Manuel; Arroyo, Eduardo; Barbujani, Guido; Beckman, Gunhild; Beckman, Lars; Bertranpetit, Jaume; Bosch, Elena; Bradley, Daniel G.; Brede, Gaute; Cooper, Gillian; Côrte-Real, Helena B. S. M.; de Knijff, Peter; Decorte, Ronny; Dubrova, Yuri E.; Evgrafov, Oleg; Gilissen, Anja; Glisic, Sanja; Gölge, Mukaddes; Hill, Emmeline W.; Jeziorowska, Anna; Kalaydjieva, Luba; Kayser, Manfred; Kivisild, Toomas; Kravchenko, Sergey A.; Krumina, Astrida; Kučinskas, Vaidutis; Lavinha, João; Livshits, Ludmila A.; Malaspina, Patrizia; Maria, Syrrou; McElreavey, Ken; Meitinger, Thomas A.; Mikelsaar, Aavo-Valdur; Mitchell, R. John; Nafa, Khedoudja; Nicholson, Jayne; Nørby, Søren; Pandya, Arpita; Parik, Jüri; Patsalis, Philippos C.; Pereira, Luísa; Peterlin, Borut; Pielberg, Gerli; Prata, Maria João; Previderé, Carlo; Roewer, Lutz; Rootsi, Siiri; Rubinsztein, D. C.; Saillard, Juliette; Santos, Fabrício R.; Stefanescu, Gheorghe; Sykes, Bryan C.; Tolun, Aslihan; Villems, Richard; Tyler-Smith, Chris; Jobling, Mark A.

    2000-01-01

    Clinal patterns of autosomal genetic diversity within Europe have been interpreted in previous studies in terms of a Neolithic demic diffusion model for the spread of agriculture; in contrast, studies using mtDNA have traced many founding lineages to the Paleolithic and have not shown strongly clinal variation. We have used 11 human Y-chromosomal biallelic polymorphisms, defining 10 haplogroups, to analyze a sample of 3,616 Y chromosomes belonging to 47 European and circum-European populations. Patterns of geographic differentiation are highly nonrandom, and, when they are assessed using spatial autocorrelation analysis, they show significant clines for five of six haplogroups analyzed. Clines for two haplogroups, representing 45% of the chromosomes, are continentwide and consistent with the demic diffusion hypothesis. Clines for three other haplogroups each have different foci and are more regionally restricted and are likely to reflect distinct population movements, including one from north of the Black Sea. Principal-components analysis suggests that populations are related primarily on the basis of geography, rather than on the basis of linguistic affinity. This is confirmed in Mantel tests, which show a strong and highly significant partial correlation between genetics and geography but a low, nonsignificant partial correlation between genetics and language. Genetic-barrier analysis also indicates the primacy of geography in the shaping of patterns of variation. These patterns retain a strong signal of expansion from the Near East but also suggest that the demographic history of Europe has been complex and influenced by other major population movements, as well as by linguistic and geographic heterogeneities and the effects of drift. PMID:11078479

  20. Compensatory increases in nuclear PGC1alpha protein are primarily associated with subsarcolemmal mitochondrial adaptations in ZDF rats.

    PubMed

    Holloway, Graham P; Gurd, Brendon J; Snook, Laelie A; Lally, Jamie; Bonen, Arend

    2010-04-01

    We examined in insulin-resistant muscle if, in contrast to long-standing dogma, mitochondrial fatty acid oxidation is increased and whether this is attributed to an increased nuclear content of peroxisome proliferator-activated receptor (PPAR) gamma coactivator (PGC) 1alpha and the adaptations of specific mitochondrial subpopulations. Skeletal muscles from male control and Zucker diabetic fatty (ZDF) rats were used to determine 1) intramuscular lipid distribution, 2) subsarcolemmal and intermyofibrillar mitochondrial morphology, 3) rates of palmitate oxidation in subsarcolemmal and intermyofibrillar mitochondria, and 4) the subcellular localization of PGC1alpha. Electotransfection of PGC1alpha cDNA into lean animals tested the notion that increased nuclear PGC1alpha preferentially targeted subsarcolemmal mitochondria. Transmission electron microscope analysis revealed that in ZDF animals the number (+50%), width (+69%), and density (+57%) of subsarcolemmal mitochondria were increased (P < 0.05). In contrast, intermyofibrillar mitochondria remained largely unchanged. Rates of palmitate oxidation were approximately 40% higher (P < 0.05) in ZDF subsarcolemmal and intermyofibrillar mitochondria, potentially as a result of the increased PPAR-targeted proteins, carnitine palmitoyltransferase-I, and fatty acid translocase (FAT)/CD36. PGC1alpha mRNA and total protein were not altered in ZDF animals; however, a greater (approximately 70%; P < 0.05) amount of PGC1alpha was located in nuclei. Overexpression of PGC1alpha only increased subsarcolemmal mitochondrial oxidation rates. In ZDF animals, intramuscular lipids accumulate in the intermyofibrillar region (increased size and number), and this is primarily associated with increased oxidative capacity in subsarcolemmal mitochondria (number, size, density, and oxidation rates). These changes may result from an increased nuclear content of PGC1alpha, as under basal conditions, overexpression of PGC1alpha appears to target

  1. Mutant alleles of small effect are primarily responsible for the loss of fitness with slow inbreeding in Drosophila melanogaster.

    PubMed

    Latter, B D

    1998-03-01

    Multilocus simulation is used to identify genetic models that can account for the observed rates of inbreeding and fitness decline in laboratory populations of Drosophila melanogaster. The experimental populations were maintained under crowded conditions for approximately 200 generations at a harmonic mean population size of Nh approximately 65-70. With a simulated population size of N = 50, and a mean selective disadvantage of homozygotes at individual loci approximately 1-2% or less, it is demonstrated that the mean effective population size over a 200-generation period may be considerably greater than N, with a ratio matching the experimental estimate of Ne/Nh approximately 1.4. The buildup of associative overdominance at electrophoretic marker loci is largely responsible for the stability of gene frequencies and the observed reduction in the rate of inbreeding, with apparent selection coefficients in favor of the heterozygote at neutral marker loci increasing rapidly over the first N generations of inbreeding to values approximately 5-10%. The observed decline in fitness under competitive conditions in populations of size approximately 50 in D. melanogaster therefore primarily results from mutant alleles with mean effects on fitness as homozygotes of sm < or = 0.02. Models with deleterious recessive mutants at the background loci require that the mean selection coefficient against heterozygotes is at most hsm approximately 0.002, with a minimum mutation rate for a single Drosophila autosome 100 cM in length estimated to be in the range 0.05-0.25, assuming an exponential distribution of s. A typical chromosome would be expected to carry at least 100-200 such mutant alleles contributing to the decline in competitive fitness with slow inbreeding.

  2. Initial Molecular-Level Response to Artificial Selection for Increased Aerobic Metabolism Occurs Primarily through Changes in Gene Expression.

    PubMed

    Konczal, Mateusz; Babik, Wiesław; Radwan, Jacek; Sadowska, Edyta T; Koteja, Paweł

    2015-06-01

    Experimental evolution combined with genome or transcriptome resequencing (Evolve and Resequence) represents a promising approach for advancing our understanding of the genetic basis of adaptation. Here, we applied this strategy to investigate the effect of selection on a complex trait in lines derived from a natural population of a small mammal. We analyzed the liver and heart transcriptomes of bank voles (Myodes [=Clethrionomys] glareolus) that had been selected for increased aerobic metabolism. The organs were sampled from 13th generation voles; at that point, the voles from four replicate selected lines had 48% higher maximum rates of oxygen consumption than those from four control lines. At the molecular level, the response to selection was primarily observed in gene expression: Over 300 genes were found to be differentially expressed between the selected and control lines and the transcriptome-wide pattern of expression distinguished selected lines from controls. No evidence for selection-driven changes of allele frequencies at coding sites was found: No single nucleotide polymorphism (SNP) changed frequency more than expected under drift alone and frequency changes aggregated over all SNPs did not separate selected and control lines. Nevertheless, among genes which showed highest differentiation in allele frequencies between selected and control lines we identified, using information about gene functions and the biology of the selected phenotype, plausible targets of selection; these genes, together with those identified in expression analysis, have been prioritized for further studies. Because our selection lines were derived from a natural population, the amount and the spectrum of variation available for selection probably closely approximated that typically found in populations of small mammals. Therefore, our results are relevant to the understanding of the molecular basis of complex adaptations occurring in natural vertebrate populations.

  3. Spin Orientation of Two-Dimensional Electrons Driven by Temperature-Tunable Competition of Spin-Orbit and Exchange-Magnetic Interactions.

    PubMed

    Generalov, Alexander; Otrokov, Mikhail M; Chikina, Alla; Kliemt, Kristin; Kummer, Kurt; Höppner, Marc; Güttler, Monika; Seiro, Silvia; Fedorov, Alexander; Schulz, Susanne; Danzenbächer, Steffen; Chulkov, Evgueni V; Geibel, Christoph; Laubschat, Clemens; Dudin, Pavel; Hoesch, Moritz; Kim, Timur; Radovic, Milan; Shi, Ming; Plumb, Nicholas C; Krellner, Cornelius; Vyalikh, Denis V

    2017-02-08

    Finding ways to create and control the spin-dependent properties of two-dimensional electron states (2DESs) is a major challenge for the elaboration of novel spin-based devices. Spin-orbit and exchange-magnetic interactions (SOI and EMI) are two fundamental mechanisms that enable access to the tunability of spin-dependent properties of carriers. The silicon surface of HoRh2Si2 appears to be a unique model system, where concurrent SOI and EMI can be visualized and controlled by varying the temperature. The beauty and simplicity of this system lie in the 4f moments, which act as a multiple tuning instrument on the 2DESs, as the 4f projections parallel and perpendicular to the surface order at essentially different temperatures. Here we show that the SOI locks the spins of the 2DESs exclusively in the surface plane when the 4f moments are disordered: the Rashba-Bychkov effect. When the temperature is gradually lowered and the system experiences magnetic order, the rising EMI progressively competes with the SOI leading to a fundamental change in the spin-dependent properties of the 2DESs. The spins rotate and reorient toward the out-of-plane Ho 4f moments. Our findings show that the direction of the spins and the spin-splitting of the two-dimensional electrons at the surface can be manipulated in a controlled way by using only one parameter: the temperature.

  4. 49 CFR 37.195 - Purchase or lease of OTRBs by private entities not primarily in the business of transporting people.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Buses (OTRBs) § 37.195 Purchase or lease of OTRBs by private entities not primarily in the business of... are not primarily engaged in the business of transporting people, with respect to buses delivered to... required to purchase or lease an accessible bus except as needed to meet the requirements of § 37.189....

  5. 49 CFR 37.195 - Purchase or lease of OTRBs by private entities not primarily in the business of transporting people.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Buses (OTRBs) § 37.195 Purchase or lease of OTRBs by private entities not primarily in the business of... are not primarily engaged in the business of transporting people, with respect to buses delivered to... required to purchase or lease an accessible bus except as needed to meet the requirements of § 37.189....

  6. 49 CFR 37.195 - Purchase or lease of OTRBs by private entities not primarily in the business of transporting people.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Buses (OTRBs) § 37.195 Purchase or lease of OTRBs by private entities not primarily in the business of... are not primarily engaged in the business of transporting people, with respect to buses delivered to... required to purchase or lease an accessible bus except as needed to meet the requirements of § 37.189....

  7. 49 CFR 37.195 - Purchase or lease of OTRBs by private entities not primarily in the business of transporting people.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Buses (OTRBs) § 37.195 Purchase or lease of OTRBs by private entities not primarily in the business of... are not primarily engaged in the business of transporting people, with respect to buses delivered to... required to purchase or lease an accessible bus except as needed to meet the requirements of § 37.189....

  8. 49 CFR 37.103 - Purchase or lease of new non-rail vehicles by private entities primarily engaged in the business...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-rail vehicles by private entities primarily engaged in the business of transporting people. Link to an... 49 Transportation 1 2011-10-01 2011-10-01 false Purchase or lease of new non-rail vehicles by private entities primarily engaged in the business of transporting people. 37.103 Section...

  9. 49 CFR 37.103 - Purchase or lease of new non-rail vehicles by private entities primarily engaged in the business...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-rail vehicles by private entities primarily engaged in the business of transporting people. (a... 49 Transportation 1 2010-10-01 2010-10-01 false Purchase or lease of new non-rail vehicles by private entities primarily engaged in the business of transporting people. 37.103 Section...

  10. Metabolic rates of benthic deep-sea decapod crustaceans decline with increasing depth primarily due to the decline in temperature

    NASA Astrophysics Data System (ADS)

    Childress, J. J.; Cowles, D. L.; Favuzzi, J. A.; Mickel, T. J.

    1990-06-01

    penaeids and carideans. In contrast, the carideans showed a significant effect of depth on metabolic rate. This is discussed in terms of the adaptive and selective factors responsible for the well-known decline in metabolic rates of midwater crustaceans and fishes, an effect which does exceed the effect of temperature. It is suggested that the typical pattern for deeper living animals may be that metabolic rates on average vary as a function of depth due primarily to variation in temperature, except for the visually orienting pelagic groups (cephalopods, crustaceans and fishes). For those benthic forms which are particularly visually oriented and/or partially pelagic some significant depth-related decline in metabolism beyond that due to the decline in temperature is expected.

  11. Outcome of aortic surgery in patients with Loeys-Dietz syndrome primarily treated as having Marfan syndrome.

    PubMed

    Schoenhoff, Florian S; Mueller, Christoph; Czerny, Martin; Matyas, Gabor; Kadner, Alexander; Schmidli, Juerg; Carrel, Thierry

    2014-09-01

    Loeys-Dietz syndrome (LDS) is characterized by acute aortic dissection (AAD) at aortic diameters below thresholds for intervention in patients with Marfan syndrome (MFS). The aim was to evaluate the outcome of LDS patients primarily treated as having MFS. We analysed 68 consecutive patients who underwent surgery between 1995 and 2007 under the assumption of having MFS before retrospectively being screened for LDS when genetic testing became available. These patients were followed up until 2013, and underwent a total of 115 aortic surgeries. Genetic testing was performed in 76% of the patients. Sixty per cent of these patients were positive for FBN1 mutations associated with MFS, 20% had no FBN1 mutation and 17% harboured TGFBR1/2 mutations associated with LDS. Mean follow-up was 12.7 ± 7 years. All-cause 30-day, 6-month and 1-year mortality rates were 2.9, 4.4 and 7.3%, respectively. Interestingly, initial presentation with AAD did not differ between LDS and MFS (33 vs 37%, P = 0.48) nor did long-term mortality compared with MFS patients (11 vs 16%, P = 1.0) or within MFS subgroups (FBN1 positive 13%, P = 1.0; FBN1 negative 10%, P = 1.0; not tested 25%, P = 0.62). There was no difference in the need for secondary total arch replacement between LDS and MFS patients (11 vs 14%, P = 1.0), nor within MFS subgroups (FBN1 positive 16%, P = 1.0; FBN1 negative 10%, P = 1.0; not tested 13%, P = 1.0). Total aortic replacement became necessary in 22% of LDS compared with 12% of MFS patients (P = 0.6) and did not differ significantly between MFS subgroups. Although early surgical intervention in LDS is warranted to avoid AAD, the current data suggest that once the diseased segment is repaired, there seems to be no additional burden in terms of mortality or reoperation rate compared with that in MFS patients, with or without confirmed FBN1 mutation. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All

  12. TRPA1 Is Functionally Expressed Primarily by IB4-Binding, Non-Peptidergic Mouse and Rat Sensory Neurons

    PubMed Central

    Stucky, Cheryl L.

    2012-01-01

    expressed primarily in the IB4-positive, CGRP-negative subpopulation of small lumbar DRG neurons from rodents. Thus, IB4 binding is a better indicator than neuropeptides for TRPA1 expression. PMID:23133534

  13. TRPA1 is functionally expressed primarily by IB4-binding, non-peptidergic mouse and rat sensory neurons.

    PubMed

    Barabas, Marie E; Kossyreva, Elena A; Stucky, Cheryl L

    2012-01-01

    expressed primarily in the IB4-positive, CGRP-negative subpopulation of small lumbar DRG neurons from rodents. Thus, IB4 binding is a better indicator than neuropeptides for TRPA1 expression.

  14. TUMOR NECROSIS FACTOR ALPHA DECREASES NOS3 EXPRESSION PRIMARILY VIA RHO/RHO KINASE IN THE THICK ASCENDING LIMB

    PubMed Central

    Ramseyer, Vanesa; Hong, Nancy; Garvin, Jeffrey L.

    2013-01-01

    Inappropriate Na+ reabsorption by thick ascending limbs (THALs) induces hypertension. Nitric oxide (NO) produced by NO synthase type 3 (NOS3 or eNOS) inhibits NaCl reabsorption by THALs. Tumor necrosis factor alpha (TNF-α) decreases NOS3 expression in endothelial cells and contributes to increases in blood pressure. However, the effects of TNF-α on THAL NOS3 and the signaling cascade are unknown. TNF-α activates several signaling pathways including Rho/Rho kinase (ROCK) which is known to reduce NOS3 expression in endothelial cells. Therefore, we hypothesized that TNF-α decreases NOS3 expression via Rho/ROCK in rat THAL primary cultures. THAL cells were incubated with either vehicle or 1 nmol/L TNF-α for 24 hrs and NOS3 expression was measured by Western blot. TNF-α decreased NOS3 expression by 51±6% (p<0.002) and blunted stimulus-induced NO production. A 10-minutes treatment with TNF-α stimulated RhoA activity by 60±23% (p<0.04). Inhibition of Rho GTPase with 0.05 μg/mL C3 exoenzyme blocked TNF-α-induced reductions in NOS3 expression by 30±8% (p<0.02). Inhibition of ROCK with 10 μmol/L H-1152 blocked TNF-α-induced decreases in NOS3 expression by 66±15 % (p<0.001). Simultaneous inhibition of Rho and ROCK had no additive effect. Myosin light chain kinase, NO, protein kinase C, mitogen-activated kinase kinase, c-Jun amino terminal kinases and Rac-1 were also not involved in TNF-α-induced decreases in NOS3 expression. We conclude that TNF-α decreases NOS3 expression primarily via Rho/ROCK in rat THALs. These data suggest that some of the beneficial effects of ROCK inhibitors in hypertension could be due to the mitigation of TNF-α-induced reduction in NOS3 expression. PMID:22566503

  15. Little-known truths, quirky anecdotes, seething scandals, and even some science in the history of (primarily achievement) motivation.

    PubMed

    Weiner, Bernard

    2013-08-01

    This article presents a history of the study of motivation from approximately 1900-1975, focusing on achievement strivings and containing little-known and often surprising facts about the main contributors to this field. Four theorists are highlighted: David McClelland, Kurt Lewin, John Atkinson, and Fritz Heider, each associated with a different theoretical approach (respectively and in order of historical emergence: trait, Gestalt, expectancy/value, and attribution theory). A fifth conception, drive theory, is also represented. In addition, a number of individuals who influenced these theorists and others who followed them are discussed. The article emphasizes the interrelations between the theorists and the interaction between personal and scientific life.

  16. MULTIMERIN2 binds VEGF-A primarily via the carbohydrate chains exerting an angiostatic function and impairing tumor growth

    PubMed Central

    Andreuzzi, Eva; Paulitti, Alice; Tarticchio, Giulia; Todaro, Federico; Colombatti, Alfonso; Mongiat, Maurizio

    2016-01-01

    Angiogenesis is a key process occurring under both physiological and pathological conditions and is a hallmark of cancer. We have recently demonstrated that the extracellular matrix (ECM) molecule MULTIMERIN2 exerts an angiostatic function through the binding to VEGF-A. In this study we identify the region of the molecule responsible for the binding and demonstrate that the interaction involves the carbohydrate chains. MULTIMERIN2 interacts with other VEGF-A isoforms and VEGF family members such as VEGF-B, -C, -D and PlGF-1 suggesting that the molecule may function as a reservoir for different cytokines. In response to VEGF-A165, we show that MULTIMERIN2 impairs the phosphorylation of VEGFR2 at both Y1175 and Y1214 residues, halts SAPK2/p38 activation and negatively affects endothelial cell motility. In addition, MULTIMERIN2 and its active deletion mutant decrease the availability of the VEGFR2 receptor at the EC plasma membrane. The ectopic expression of MULTIMERIN2 or its active deletion mutant led to a striking reduction of tumor-associated angiogenesis and tumor growth. In conclusion, these data pinpoint MULTIMERIN2 as a key angiostatic molecule and disclose the possibility to develop new prognostic tools and improve the management of cancer patients. PMID:26655500

  17. Interaction effects in a microscopic quantum wire model with strong spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Winkler, G. W.; Ganahl, M.; Schuricht, D.; Evertz, H. G.; Andergassen, S.

    2017-06-01

    We investigate the effect of strong interactions on the spectral properties of quantum wires with strong Rashba spin-orbit (SO) interaction in a magnetic field, using a combination of matrix product state and bosonization techniques. Quantum wires with strong Rashba SO interaction and magnetic field exhibit a partial gap in one-half of the conducting modes. Such systems have attracted wide-spread experimental and theoretical attention due to their unusual physical properties, among which are spin-dependent transport, or a topological superconducting phase when under the proximity effect of an s-wave superconductor. As a microscopic model for the quantum wire we study an extended Hubbard model with SO interaction and Zeeman field. We obtain spin resolved spectral densities from the real-time evolution of excitations, and calculate the phase diagram. We find that interactions increase the pseudo gap at k = 0 and thus also enhance the Majorana-supporting phase and stabilize the helical spin order. Furthermore, we calculate the optical conductivity and compare it with the low energy spiral Luttinger liquid result, obtained from field theoretical calculations. With interactions, the optical conductivity is dominated by an excotic excitation of a bound soliton-antisoliton pair known as a breather state. We visualize the oscillating motion of the breather state, which could provide the route to their experimental detection in e.g. cold atom experiments.

  18. Antibody uptake into neurons occurs primarily via clathrin-dependent Fcγ receptor endocytosis and is a prerequisite for acute tau protein clearance.

    PubMed

    Congdon, Erin E; Gu, Jiaping; Sait, Hameetha B R; Sigurdsson, Einar M

    2013-12-06

    Tau immunotherapy is effective in transgenic mice, but the mechanisms of Tau clearance are not well known. To this end, Tau antibody uptake was analyzed in brain slice cultures and primary neurons. Internalization was rapid (<1 h), saturable, and substantial compared with control mouse IgG. Furthermore, temperature reduction to 4 °C, an excess of unlabeled mouse IgG, or an excess of Tau antibodies reduced uptake in slices by 63, 41, and 62%, respectively (p = 0.002, 0.04, and 0.005). Uptake strongly correlated with total and insoluble Tau levels (r(2) = 0.77 and 0.87 and p = 0.002 and 0.0002), suggesting that Tau aggregates influence antibody internalization and/or retention within neurons. Inhibiting phagocytosis did not reduce uptake in slices or neuronal cultures, indicating limited microglial involvement. In contrast, clathrin-specific inhibitors reduced uptake in neurons (≤ 78%, p < 0.0001) and slices (≤ 35%, p = 0.03), demonstrating receptor-mediated endocytosis as the primary uptake pathway. Fluid phase endocytosis accounted for the remainder of antibody uptake in primary neurons, based on co-staining with internalized dextran. The receptor-mediated uptake is to a large extent via low affinity FcγII/III receptors and can be blocked in slices (43%, p = 0.04) and neurons (53%, p = 0.008) with an antibody against these receptors. Importantly, antibody internalization appears to be necessary for Tau reduction in primary neurons. Overall, these findings clarify that Tau antibody uptake is primarily receptor-mediated, that these antibodies are mainly found in neurons with Tau aggregates, and that their intracellular interaction leads to clearance of Tau pathology, all of which have major implications for therapeutic development of this approach.

  19. Water deficit in field-grown Gossypium hirsutum primarily limits net photosynthesis by decreasing stomatal conductance, increasing photorespiration, and increasing the ratio of dark respiration to gross photosynthesis.

    PubMed

    Chastain, Daryl R; Snider, John L; Collins, Guy D; Perry, Calvin D; Whitaker, Jared; Byrd, Seth A

    2014-11-01

    Much effort has been expended to improve irrigation efficiency and drought tolerance of agronomic crops; however, a clear understanding of the physiological mechanisms that interact to decrease source strength and drive yield loss has not been attained. To elucidate the underlying mechanisms contributing to inhibition of net carbon assimilation under drought stress, three cultivars of Gossypium hirsutum were grown in the field under contrasting irrigation regimes during the 2012 and 2013 growing season near Camilla, Georgia, USA. Physiological measurements were conducted on three sample dates during each growing season (providing a broad range of plant water status) and included, predawn and midday leaf water potential (ΨPD and ΨMD), gross and net photosynthesis, dark respiration, photorespiration, and chlorophyll a fluorescence. End-of-season lint yield was also determined. ΨPD ranged from -0.31 to -0.95MPa, and ΨMD ranged from -1.02 to -2.67MPa, depending upon irrigation regime and sample date. G. hirsutum responded to water deficit by decreasing stomatal conductance, increasing photorespiration, and increasing the ratio of dark respiration to gross photosynthesis, thereby limiting PN and decreasing lint yield (lint yield declines observed during the 2012 growing season only). Conversely, even extreme water deficit, causing a 54% decline in PN, did not negatively affect actual quantum yield, maximum quantum yield, or photosynthetic electron transport. It is concluded that PN is primarily limited in drought-stressed G. hirsutum by decreased stomatal conductance, along with increases in respiratory and photorespiratory carbon losses, not inhibition or down-regulation of electron transport through photosystem II. It is further concluded that ΨPD is a reliable indicator of drought stress and the need for irrigation in field-grown cotton.

  20. Magnetoresistance and electron-hole exchange interaction in (Co{sub 1-x}In{sub x}){sub 2}O{sub 3-v} concentrated ferromagnetic semiconductors

    SciTech Connect

    Xu, T. S.; Qiao, R. M.; Tian, Y. F.; Yan, S. S. Zhang, K.; Cao, Y. L.; Kang, S. S.; Chen, Y. X.; Liu, G. L.; Mei, L. M.

    2013-11-11

    Systematic studies of electrical transport properties of (Co{sub 1-x}In{sub x}){sub 2}O{sub 3-v} concentrated ferromagnetic semiconductors were performed. Quantitative analysis demonstrated that spin dependent variable range hopping dominated the low temperature transport behavior. Moreover, it was found that ferromagnetic or antiferromagnetic coupling of electron-hole pair generated during the variable range hopping process is responsible for the negative or positive magnetoresistance, respectively. Our results not only illustrate the connection between magnetoresistance and electron-hole exchange interaction but also provide a unique method to detect the exchange interaction of electron-hole pair.

  1. Parton interpretation of the nucleon spin-dependent structure functions

    SciTech Connect

    Mankiewicz, L. ); Ryzak, Z. )

    1991-02-01

    We discuss the interpretation of the nucleon's polarized structure function {ital g}{sub 2}({ital x}). If the target state is represented by its Fock decomposition on the light cone, the operator-product expansion allows us to demonstrate that moments of {ital g}{sub 2}({ital x}) are related to overlap integrals between wave functions of opposite longitudinal polarizations. In the light-cone formalism such wave functions are related by the kinematical operator {ital scrY}, or light-cone parity. As a consequence, it can be shown that moments of {ital g}{sub 2} give information about the same parton wave function, or probability amplitude to find a certain parton configuration in the target which defines {ital g}{sub 1}({ital x}) or {ital F}{sub 2}({ital x}). Specific formulas are given, and possible applications to the phenomenology of the nucleon structure in QCD are discussed.

  2. Giant spin-dependent thermoelectric effect in magnetic tunnel junctions.

    PubMed

    Lin, Weiwei; Hehn, Michel; Chaput, Laurent; Negulescu, Béatrice; Andrieu, Stéphane; Montaigne, François; Mangin, Stéphane

    2012-03-20

    Thermoelectric effects in magnetic nanostructures and the so-called spin caloritronics are attracting much interest. Indeed it provides a new way to control and manipulate spin currents, which are key elements of spin-based electronics. Here we report on a giant magnetothermoelectric effect in a magnetic tunnel junction. The thermovoltage in this geometry can reach 1 mV. Moreover a magnetothermovoltage effect could be measured with ratio similar to the tunnel magnetoresistance ratio. The Seebeck coefficient can then be tuned by changing the relative magnetization orientation of the two magnetic layers in the tunnel junction. Therefore, our experiments extend the range of spintronic devices application to thermoelectricity and provide a crucial piece of information for understanding the physics of thermal spin transport.

  3. Spin-dependent conductance of small graphene flakes

    NASA Astrophysics Data System (ADS)

    Tugrul Senger, R.; Sahin, Hasan; Ciraci, Salim

    2010-03-01

    Using ab initio density-functional theory and quantum transport calculations based on nonequilibrium Green's function formalism we study structural, electronic, and transport properties of small graphene flakes. Rectangular and triangular graphene flakes are stable, having magnetically ordered edge states. We show that a spin-polarized current can be produced in pure, hydrogenated, rectangular graphene flakes by exploiting the spatially separated edge states of the flake using asymmetric, nonmagnetic contacts (1). Sharp discontinuities in the transmission spectra which arise from Fano resonances of localized states in the flake are also predicted. Functionalization of the graphene flake with magnetic adatoms such as vanadium also leads to spin-polarized currents even with symmetric contacts. Ground state of triangular flakes have non-zero magnetic moments and their conductance are spin polarized. (1) H. Sahin and R. T. Senger, Phys. Rev. B 78, 205423 (2008).

  4. Spin-dependent electron transport in manganite bicrystal junctions

    SciTech Connect

    Petrzhik, A. M. Demidov, V. V.; Ovsyannikov, G. A.; Borisenko, I. V.; Shadrin, A. V.

    2012-11-15

    Magnetic bicrystal films and junctions of magnetic La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LSMO) and La{sub 0.67}Ca{sub 0.33}MnO{sub 3} (LCMO) films epitaxially grown on NdGaO{sub 3} substrates with the (110) planes of their two parts misoriented (tilted) at angles of 12 Degree-Sign , 22 Degree-Sign , 28 Degree-Sign , and 38 Degree-Sign are investigated. For comparison, bicrystal boundaries with a 90 Degree-Sign misorientation of the axes of the NdGaO{sub 3} (110) planes were fabricated. The directions of the axes and the magnetic anisotropy constants of the films on both sides of the boundary are determined by two independent techniques of magnetic resonance spectroscopy. The magnetic misorientation of the axes in the substrate plane has been found to be much smaller than the crystallographic misorientation for tilted bicrystal boundaries, while the crystallographic and magnetic misorientation angles coincide for boundaries with rotation of the axes. An increase in the magnetoresistance and characteristic resistance of bicrystal junctions with increasing misorientation angle was observed experimentally. The magnetoresistance of bicrystal junctions has been calculated by taking into account the uniaxial anisotropy, which has allowed the contributions from the tunneling and anisotropic magnetoresistances to be separated. The largest tunneling magnetoresistance was observed on LCMO bicrystal junctions, in which the characteristic resistance of the boundary is higher than that in LSMO boundaries.

  5. Spin-dependent quantum interference within a single magnetic nanostructure.

    PubMed

    Oka, H; Ignatiev, P A; Wedekind, S; Rodary, G; Niebergall, L; Stepanyuk, V S; Sander, D; Kirschner, J

    2010-02-12

    Quantum interference is a coherent quantum phenomenon that takes place in confined geometries. Using spin-polarized scanning tunneling microscopy, we found that quantum interference of electrons causes spatial modulation of spin polarization within a single magnetic nanostructure. We observed changes in both the sign and magnitude of the spin polarization on a subnanometer scale. A comparison of our experimental results with ab initio calculations shows that at a given energy, the modulation of the spin polarization can be ascribed to the difference between the spatially modulated local density of states of the majority spin and the nonmodulated minority spin contribution.

  6. Spin-dependent quark beam function at NNLO

    NASA Astrophysics Data System (ADS)

    Boughezal, Radja; Petriello, Frank; Schubert, Ulrich; Xing, Hongxi

    2017-08-01

    We calculate the beam function for longitudinally polarized quarks through next-to-next-to-leading order (NNLO) in QCD perturbation theory. This is the last missing ingredient needed to apply the factorization theorem for the N -jettiness event-shape variable in a variety of polarized collisions through the NNLO level. We present all technical details of our derivation. As a by-product of our calculation we provide the first independent check of the previously obtained unpolarized quark beam function. We anticipate that our result will have phenomenological applications in describing data from polarized collisions.

  7. Spin-dependent Peltier effect in Co /Cu multilayer nanowires

    NASA Astrophysics Data System (ADS)

    Gravier, Laurent; Serrano-Guisan, Santiago; Ansermet, J.-Ph.

    2005-05-01

    Heat transport perpendicular to the plane of magnetic multilayers is monitored with ac temperature gradients in the presence of a direct charge current. A very strong dependence on the applied magnetic field of the voltage response to the ac gradient is observed using Co /Cu multilayered nanowires. The effect is interpreted as a Peltier effect for a one-dimensional heat flux.

  8. Translating an effective group-based HIV prevention program to a program delivered primarily by a computer: methods and outcomes.

    PubMed

    Card, Josefina J; Kuhn, Tamara; Solomon, Julie; Benner, Tabitha A; Wingood, Gina M; DiClemente, Ralph J

    2011-04-01

    We describe development of SAHARA (SISTAS Accessing HIV/AIDS Resources At-a-click), an innovative HIV prevention program that uses a computer to deliver an updated version of SiSTA, a widely used, effective group-level HIV prevention intervention for African American women ages 18-29. Fidelity to SiSTA's core components was achieved using: (1) video clips featuring group discussions and modeling of appropriate sexual- and contraceptive-related behavior; and (2) interactive Flash modules facilitating cognitive rehearsal, providing learning experiences through games and quizzes, and providing opportunities for simulated role-play. A preliminary outcome study of SAHARA conducted at Planned Parenthood, Atlanta, found that SAHARA, when followed by a brief 20-minute wrap-up group session facilitated by a health educator, was effective in promoting consistent condom use for vaginal sex. We discuss the potential advantages and challenges of an intervention like SAHARA delivered by computer to an individual, versus one like SiSTA delivered by a health educator to a small group.

  9. The Groucho Co-repressor Is Primarily Recruited to Local Target Sites in Active Chromatin to Attenuate Transcription

    PubMed Central

    Jennings, Barbara H.

    2014-01-01

    Gene expression is regulated by the complex interaction between transcriptional activators and repressors, which function in part by recruiting histone-modifying enzymes to control accessibility of DNA to RNA polymerase. The evolutionarily conserved family of Groucho/Transducin-Like Enhancer of split (Gro/TLE) proteins act as co-repressors for numerous transcription factors. Gro/TLE proteins act in several key pathways during development (including Notch and Wnt signaling), and are implicated in the pathogenesis of several human cancers. Gro/TLE proteins form oligomers and it has been proposed that their ability to exert long-range repression on target genes involves oligomerization over broad regions of chromatin. However, analysis of an endogenous gro mutation in Drosophila revealed that oligomerization of Gro is not always obligatory for repression in vivo. We have used chromatin immunoprecipitation followed by DNA sequencing (ChIP-seq) to profile Gro recruitment in two Drosophila cell lines. We find that Gro predominantly binds at discrete peaks (<1 kilobase). We also demonstrate that blocking Gro oligomerization does not reduce peak width as would be expected if Gro oligomerization induced spreading along the chromatin from the site of recruitment. Gro recruitment is enriched in “active” chromatin containing developmentally regulated genes. However, Gro binding is associated with local regions containing hypoacetylated histones H3 and H4, which is indicative of chromatin that is not fully open for efficient transcription. We also find that peaks of Gro binding frequently overlap the transcription start sites of expressed genes that exhibit strong RNA polymerase pausing and that depletion of Gro leads to release of polymerase pausing and increased transcription at a bona fide target gene. Our results demonstrate that Gro is recruited to local sites by transcription factors to attenuate rather than silence gene expression by promoting histone deacetylation

  10. The Groucho co-repressor is primarily recruited to local target sites in active chromatin to attenuate transcription.

    PubMed

    Kaul, Aamna; Schuster, Eugene; Jennings, Barbara H

    2014-08-01

    Gene expression is regulated by the complex interaction between transcriptional activators and repressors, which function in part by recruiting histone-modifying enzymes to control accessibility of DNA to RNA polymerase. The evolutionarily conserved family of Groucho/Transducin-Like Enhancer of split (Gro/TLE) proteins act as co-repressors for numerous transcription factors. Gro/TLE proteins act in several key pathways during development (including Notch and Wnt signaling), and are implicated in the pathogenesis of several human cancers. Gro/TLE proteins form oligomers and it has been proposed that their ability to exert long-range repression on target genes involves oligomerization over broad regions of chromatin. However, analysis of an endogenous gro mutation in Drosophila revealed that oligomerization of Gro is not always obligatory for repression in vivo. We have used chromatin immunoprecipitation followed by DNA sequencing (ChIP-seq) to profile Gro recruitment in two Drosophila cell lines. We find that Gro predominantly binds at discrete peaks (<1 kilobase). We also demonstrate that blocking Gro oligomerization does not reduce peak width as would be expected if Gro oligomerization induced spreading along the chromatin from the site of recruitment. Gro recruitment is enriched in "active" chromatin containing developmentally regulated genes. However, Gro binding is associated with local regions containing hypoacetylated histones H3 and H4, which is indicative of chromatin that is not fully open for efficient transcription. We also find that peaks of Gro binding frequently overlap the transcription start sites of expressed genes that exhibit strong RNA polymerase pausing and that depletion of Gro leads to release of polymerase pausing and increased transcription at a bona fide target gene. Our results demonstrate that Gro is recruited to local sites by transcription factors to attenuate rather than silence gene expression by promoting histone deacetylation and

  11. Tuning exchange interactions in organometallic semiconductors

    NASA Astrophysics Data System (ADS)

    Rawat, Naveen; Manning, Lane W.; Hua, Kim-Ngan; Headrick, Randall L.; Cherian, Judy G.; Bishop, Michael M.; McGill, Stephen A.; Furis, Madalina I.

    2015-09-01

    Organic semiconductors are emerging as a leading area of research as they are expected to overcome limitations of inorganic semiconductor devices for certain applications where low cost manufacturing, device transparency in the visible range or mechanical flexibility are more important than fast switching times. Solution processing methods produce thin films with millimeter sized crystalline grains at very low cost manufacturing prices, ideally suited for optical spectroscopy investigations of long range many-body effects in organic systems. To this end, we synthesized an entire family of organosoluble 3-d transition metal Pc's and successfully employed a novel solution-based pen-writing deposition technique to fabricate long range ordered thin films of mixtures of metal-free (H2Pc) molecule and organometallic phthalocyanines (MPc's). Our previous studies on the parent MPc crystalline thin films identified different electronic states mediating exchange interactions in these materials. This understanding of spin-dependent exchange interaction between delocalized π-electrons with unpaired d spins enabled the further tuning of these interactions by mixing CoPc and H2Pc in different ratios ranging from 1:1 to 1000:1 H2Pc:MPc. The magnitude of the exchange is also tunable as a function of the average distance between unpaired spins in these materials. Furthermore, high magnetic field (B < 25T) MCD and magneto-photoluminescence show evidence of spin-polarized band-edge excitons in the same materials.

  12. Device Applications of Spin-Orbit Interaction in Semiconductor Heterostructures

    NASA Astrophysics Data System (ADS)

    Ting, David Z.-Y.; Cartoixà, Xavier; Chang, Yia-Chung

    2005-03-01

    We report recent progress in theoretical development of two classes of non-magnetic semiconductor heterostructure spin devices that exploit spin-orbit interaction in the presence of structural inversion asymmetry (SIA) or bulk inversion asymmetry (BIA). The first uses resonant tunneling to filter spins, and can be used to create a source of spin polarized current. We will provide an analysis on the origin of spin-dependent tunneling in these structures and discuss their applications. The second exploits the interplay between BIA and SIA to control spin lifetimes for device applications. We show that the D'yakonov-Perel' spin relaxation can be suppressed to first order in k for one out three spin components in [001] and [011] heterostructures, and for all three spin components in [111] heterostructures. Our results suggest the use of [111] heterostructures as preferred channels for spin transport, as active regions in spin-LEDs, for spin lifetime transistor, and for spin storage.

  13. "That Truly Meant a Lot to Me": A Qualitative Examination of Meaningful Faculty-Student Interactions

    ERIC Educational Resources Information Center

    Grantham, Ashley; Robinson, Emily Erin; Chapman, Diane

    2015-01-01

    The majority of research on faculty-student interaction has been primarily quantitative to date and has focused primarily on determining what kinds of interactions students have with faculty. This study furthers the literature on faculty-student interaction, taking a qualitative approach to examine what types of interactions with faculty students…

  14. "That Truly Meant a Lot to Me": A Qualitative Examination of Meaningful Faculty-Student Interactions

    ERIC Educational Resources Information Center

    Grantham, Ashley; Robinson, Emily Erin; Chapman, Diane

    2015-01-01

    The majority of research on faculty-student interaction has been primarily quantitative to date and has focused primarily on determining what kinds of interactions students have with faculty. This study furthers the literature on faculty-student interaction, taking a qualitative approach to examine what types of interactions with faculty students…

  15. Weakly interacting spinor Bose-Einstein condensates with three-dimensional spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Shu-Wei, Song; Rui, Sun; Hong, Zhao; Xuan, Wang; Bao-Zhong, Han

    2016-04-01

    Starting from the Hamiltonian of the second quantization form, the weakly interacting Bose-Einstein condensate with spin-orbit coupling of Weyl type is investigated. It is found that the SU(2) nonsymmetric term, i.e., the spin-dependent interaction, can lift the degeneracy of the ground states with respect to the z component of the total angular momentum J z , casting the ground condensate state into a configuration of zero J z . This ground state density profile can also be affirmed by minimizing the full Gross-Pitaevskii energy functional. The spin texture of the zero J z state indicates that it is a knot structure, whose fundamental group is π 3(M) ≅ π 3(S 2) = Z. Project supported by the National Natural Science Foundation of China (Grant No. 11447178).

  16. Generating non-classical states from spin coherent states via interaction with ancillary spins

    NASA Astrophysics Data System (ADS)

    Dooley, Shane; Joo, Jaewoo; Proctor, Timothy; Spiller, Timothy P.

    2015-02-01

    The generation of non-classical states of large quantum systems has attracted much interest from a foundational perspective, but also because of the significant potential of such states in emerging quantum technologies. In this paper we consider the possibility of generating non-classical states of a system of spins by interaction with an ancillary system, starting from an easily prepared initial state. We extend previous results for an ancillary system comprising a single spin to bigger ancillary systems and the interaction strength is enhanced by a factor of the number of ancillary spins. Depending on initial conditions, we find - by a combination of approximation and numerics - that the system of spins can evolve to spin cat states, spin squeezed states or to multiple cat states. We also discuss some candidate systems for implementation of the Hamiltonian necessary to generate these non-classical states.

  17. Role of the electromagnetic momentum in the spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Spavieri, Gianfranco

    2016-12-01

    The role played by the linear and angular momentum of the electromagnetic fields in the understanding of several aspects of quantum mechanics is discussed. A non-relativistic semi-classical model of the spin-orbit interaction, where the electromagnetic interaction energy U is calculated in the frame of the nucleus, is presented. Taking into account the electron hidden momentum P h = c -1 μ × E, the spin-orbit energy splitting turns out to be Δℰ so = (1 / 2) U, the factor 1 / 2 emerging directly by requiring that the energy variation be a minimum. After quantization, the radius of the orbit is found to be spin-dependent, anticipating a feature of the Dirac equation. Finally, a test of the hidden momentum P h , which may corroborate the approaches based on the hidden momentum and related interpretations of electrodynamics, is proposed and shown to be viable with present technology.

  18. Covariant Spectator Theory of heavy-light and heavy mesons and the predictive power of covariant interaction kernels

    NASA Astrophysics Data System (ADS)

    Leitão, Sofia; Stadler, Alfred; Peña, M. T.; Biernat, Elmar P.

    2017-01-01

    The Covariant Spectator Theory (CST) is used to calculate the mass spectrum and vertex functions of heavy-light and heavy mesons in Minkowski space. The covariant kernel contains Lorentz scalar, pseudoscalar, and vector contributions. The numerical calculations are performed in momentum space, where special care is taken to treat the strong singularities present in the confining kernel. The observed meson spectrum is very well reproduced after fitting a small number of model parameters. Remarkably, a fit to a few pseudoscalar meson states only, which are insensitive to spin-orbit and tensor forces and do not allow to separate the spin-spin from the central interaction, leads to essentially the same model parameters as a more general fit. This demonstrates that the covariance of the chosen interaction kernel is responsible for the very accurate prediction of the spin-dependent quark-antiquark interactions.

  19. Spin Exchange Interaction in Substituted Copper Phthalocyanine Crystalline Thin Films

    PubMed Central

    Rawat, Naveen; Pan, Zhenwen; Lamarche, Cody J.; Wetherby, Anthony; Waterman, Rory; Tokumoto, Takahisa; Cherian, Judy G.; Headrick, Randall L.; McGill, Stephen A.; Furis, Madalina I.

    2015-01-01

    The origins of spin exchange in crystalline thin films of Copper Octabutoxy Phthalocyanine (Cu-OBPc) are investigated using Magnetic Circular Dichroism (MCD) spectroscopy. These studies are made possible by a solution deposition technique which produces highly ordered films with macroscopic grain sizes suitable for optical studies. For temperatures lower than 2 K, the contribution of a specific state in the valence band manifold originating from the hybridized lone pair in nitrogen orbitals of the Phthalocyanine ring, bears the Brillouin-like signature of an exchange interaction with the localized d-shell Cu spins. A comprehensive MCD spectral analysis coupled with a molecular field model of a σπ − d exchange analogous to sp-d interactions in Diluted Magnetic Semiconductors (DMS) renders an enhanced Zeeman splitting and a modified g-factor of −4 for the electrons that mediate the interaction. These studies define an experimental tool for identifying electronic states involved in spin-dependent exchange interactions in organic materials. PMID:26559337

  20. Spin Exchange Interaction in Substituted Copper Phthalocyanine Crystalline Thin Films.

    PubMed

    Rawat, Naveen; Pan, Zhenwen; Lamarche, Cody J; Wetherby, Anthony; Waterman, Rory; Tokumoto, Takahisa; Cherian, Judy G; Headrick, Randall L; McGill, Stephen A; Furis, Madalina I

    2015-11-12

    The origins of spin exchange in crystalline thin films of Copper Octabutoxy Phthalocyanine (Cu-OBPc) are investigated using Magnetic Circular Dichroism (MCD) spectroscopy. These studies are made possible by a solution deposition technique which produces highly ordered films with macroscopic grain sizes suitable for optical studies. For temperatures lower than 2 K, the contribution of a specific state in the valence band manifold originating from the hybridized lone pair in nitrogen orbitals of the Phthalocyanine ring, bears the Brillouin-like signature of an exchange interaction with the localized d-shell Cu spins. A comprehensive MCD spectral analysis coupled with a molecular field model of a σπ - d exchange analogous to sp-d interactions in Diluted Magnetic Semiconductors (DMS) renders an enhanced Zeeman splitting and a modified g-factor of -4 for the electrons that mediate the interaction. These studies define an experimental tool for identifying electronic states involved in spin-dependent exchange interactions in organic materials.

  1. Spin Exchange Interaction in Substituted Copper Phthalocyanine Crystalline Thin Films

    NASA Astrophysics Data System (ADS)

    Rawat, Naveen; Pan, Zhenwen; Lamarche, Cody J.; Wetherby, Anthony; Waterman, Rory; Tokumoto, Takahisa; Cherian, Judy G.; Headrick, Randall L.; McGill, Stephen A.; Furis, Madalina I.

    2015-11-01

    The origins of spin exchange in crystalline thin films of Copper Octabutoxy Phthalocyanine (Cu-OBPc) are investigated using Magnetic Circular Dichroism (MCD) spectroscopy. These studies are made possible by a solution deposition technique which produces highly ordered films with macroscopic grain sizes suitable for optical studies. For temperatures lower than 2 K, the contribution of a specific state in the valence band manifold originating from the hybridized lone pair in nitrogen orbitals of the Phthalocyanine ring, bears the Brillouin-like signature of an exchange interaction with the localized d-shell Cu spins. A comprehensive MCD spectral analysis coupled with a molecular field model of a σπ - d exchange analogous to sp-d interactions in Diluted Magnetic Semiconductors (DMS) renders an enhanced Zeeman splitting and a modified g-factor of -4 for the electrons that mediate the interaction. These studies define an experimental tool for identifying electronic states involved in spin-dependent exchange interactions in organic materials.

  2. Evaluating a County-Sponsored Social Marketing Campaign to Increase Mothers' Initiation of HPV Vaccine for their Pre-teen Daughters in a Primarily Rural Area.

    PubMed

    Cates, Joan R; Shafer, Autumn; Diehl, Sandra J; Deal, Allison M

    2011-01-01

    Routine vaccination against human papillomavirus (HPV), the main cause of cervical cancer, is recommended for 11-12 year old girls, yet vaccine uptake is low. This study evaluates a social marketing campaign initiated by 13 North Carolina counties to raise awareness among parents and reduce barriers to accessing the vaccine in a primarily rural area. The 3-month campaign targeted mothers of girls ages 11-12 and healthcare practices serving pre-teen girls in four counties. Principles of social marketing were: product (recommended vaccine against HPV), price (cost, perception of safety and efficacy, and access), promotion (posters, brochures, website, news releases, doctor's recommendation), and place (doctors' offices, retail outlets). We analyzed (1) website traffic, hotline calls, and media placement; (2) cross-sectional surveys of mothers and providers; and (3) HPV immunization rates in intervention versus non-intervention counties. Of respondent mothers (n=225), 82% heard or saw campaign messages or materials. Of respondent providers (n=35), 94% used campaign brochures regularly or occasionally in conversations with parents. HPV vaccination rates within six months of campaign launch were 2% higher for 9-13 year old girls in two of the four intervention counties compared to 96 non-intervention counties. This evaluation supports campaign use in other primarily rural and underserved areas.

  3. Evaluating a County-Sponsored Social Marketing Campaign to Increase Mothers’ Initiation of HPV Vaccine for their Pre-teen Daughters in a Primarily Rural Area

    PubMed Central

    Cates, Joan R.; Shafer, Autumn; Diehl, Sandra J.; Deal, Allison M.

    2011-01-01

    Routine vaccination against human papillomavirus (HPV), the main cause of cervical cancer, is recommended for 11–12 year old girls, yet vaccine uptake is low. This study evaluates a social marketing campaign initiated by 13 North Carolina counties to raise awareness among parents and reduce barriers to accessing the vaccine in a primarily rural area. The 3-month campaign targeted mothers of girls ages 11–12 and healthcare practices serving pre-teen girls in four counties. Principles of social marketing were: product (recommended vaccine against HPV), price (cost, perception of safety and efficacy, and access), promotion (posters, brochures, website, news releases, doctor’s recommendation), and place (doctors’ offices, retail outlets). We analyzed (1) website traffic, hotline calls, and media placement; (2) cross-sectional surveys of mothers and providers; and (3) HPV immunization rates in intervention versus non-intervention counties. Of respondent mothers (n=225), 82% heard or saw campaign messages or materials. Of respondent providers (n=35), 94% used campaign brochures regularly or occasionally in conversations with parents. HPV vaccination rates within six months of campaign launch were 2% higher for 9–13 year old girls in two of the four intervention counties compared to 96 non-intervention counties. This evaluation supports campaign use in other primarily rural and underserved areas. PMID:21804767

  4. Spin-polarization and spin-flip in a triple-quantum-dot ring by using tunable lateral bias voltage and Rashba spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Molavi, Mohamad; Faizabadi, Edris

    2017-04-01

    By using the Green's function formalism, we investigate the effects of single particle energy levels of a quantum dot on the spin-dependent transmission properties through a triple-quantum-dot ring structure. In this structure, one of the quantum dots has been regarded to be non-magnetic and the Rashba spin-orbit interaction is imposed locally on this dot while the two others can be magnetic. The on-site energy of dots, manipulates the interference of the electron spinors that are transmitted to output leads. Our results show that the effects of magnetic dots on spin-dependent transmission properties are the same as the difference of on-site energies of the various dots, which is applicable by a controllable lateral bias voltage externally. Besides, by tuning the parameters such as Rashba spin-orbit interaction, and on-site energy of dots and magnetic flux inside the ring, the structure can be indicated the spin-flip effect and behave as a full spin polarizer or splitter.

  5. HLA-DQ primarily confers protection and HLA-DR susceptibility in type I (Insulin-dependent) diabetes studied in population-based affected families and controls

    SciTech Connect

    Kockum, I. Univ. of Lund Karolinska Institute, Karolinska Hospital, Stockholm ); Wassmuth, R. ); Holmberg, E. ); Michelsen, B. ); Lernmark, A. Karolinska Institute, Karolinska Hospital, Stockholm )

    1993-07-01

    The association between HLA-DR and -DQ and insulin-dependent diabetes mellitus (IDDM) in a defined high-incidence area was analyzed in a total of 58 population-based patients, representing 77% of IDDM patients with age at onset below 16 years, and in 92 unrelated parents in control families without IDDM. HLA haplotypes were confirmed by analyzing first-degree relatives in both groups. Seven different methods were used to analyze risk: (1) odds ratio, (2) absolute risk, (3) haplotype relative risk, (4) transcomplementation relative risk, (5) relative predisposing effects, (6) stratification analysis, and (7) test of predisposing allele on haplotype. DQB1*0302 indicated somewhat higher risk than did DR4, while DR3 had a higher risk than DQB1*0201; however, the 95% confidence intervals of the risk estimates overlapped. The positive association between IDDM and the DQB1*0201-DQA1*0501-DR3 haplotype seems to be due to DR3 or to an unknown linked gene. More important, DQA1*0301 was present among 93% of the patients, and this allele in various transcomplementation combinations with DQBL alleles showed closer association to IDDM than did any other alleles. The strong negative association of the DQB1*0602 allele also in the presence of either DR4 or DQBI*0302 or both suggests that, in a high-risk population for IDDM, HLA-DQ primarily confers protection, perhaps by induction of tolerance. Consistent with known functions, HLA-DR may primarily confer susceptibility, perhaps by induction of autoreactive T lymphocytes. 67 refs., 3 figs., 9 tabs.

  6. Increased Costs Associated with Bloodstream Infections Caused by Multidrug-Resistant Gram-Negative Bacteria Are Due Primarily to Patients with Hospital-Acquired Infections.

    PubMed

    Thaden, Joshua T; Li, Yanhong; Ruffin, Felicia; Maskarinec, Stacey A; Hill-Rorie, Jonathan M; Wanda, Lisa C; Reed, Shelby D; Fowler, Vance G

    2017-03-01

    The clinical and economic impacts of bloodstream infections (BSI) due to multidrug-resistant (MDR) Gram-negative bacteria are incompletely understood. From 2009 to 2015, all adult inpatients with Gram-negative BSI at our institution were prospectively enrolled. MDR status was defined as resistance to ≥3 antibiotic classes. Clinical outcomes and inpatient costs associated with the MDR phenotype were identified. Among 891 unique patients with Gram-negative BSI, 292 (33%) were infected with MDR bacteria. In an adjusted analysis, only history of Gram-negative infection was associated with MDR BSI versus non-MDR BSI (odds ratio, 1.60; 95% confidence interval [CI], 1.19 to 2.16; P = 0.002). Patients with MDR BSI had increased BSI recurrence (1.7% [5/292] versus 0.2% [1/599]; P = 0.02) and longer hospital stay (median, 10.0 versus 8.0 days; P = 0.0005). Unadjusted rates of in-hospital mortality did not significantly differ between MDR (26.4% [77/292]) and non-MDR (21.7% [130/599]) groups (P = 0.12). Unadjusted mean costs were 1.62 times higher in MDR than in non-MDR BSI ($59,266 versus $36,452; P = 0.003). This finding persisted after adjustment for patient factors and appropriate empirical antibiotic therapy (means ratio, 1.18; 95% CI, 1.03 to 1.36; P = 0.01). Adjusted analysis of patient subpopulations revealed that the increased cost of MDR BSI occurred primarily among patients with hospital-acquired infections (MDR means ratio, 1.41; 95% CI, 1.10 to 1.82; P = 0.008). MDR Gram-negative BSI are associated with recurrent BSI, longer hospital stays, and increased mean inpatient costs. MDR BSI in patients with hospital-acquired infections primarily account for the increased cost.

  7. Rashba Spin Orbit Interaction and Birefringent Electron Optics in Graphene

    NASA Astrophysics Data System (ADS)

    Asmar, Mahmoud; Ulloa, Sergio

    2013-03-01

    Analogies between geometrical optics and electron trajectories have resulted in a number of interesting proposals for device applications, where material interfaces play a similar role to that of transparent interfaces in physical optics. Optical birefringence in materials arising from crystal anisotropies are manifested as different group velocities for different polarizations of light. By making use of analytical solutions of the Dirac equation, and extending the partial wave component method of scattering to include spin dependent observables, we show that an equivalent phenomenon to optical birefringence in electron optics is feasible in two dimensional graphene. The electronic birefringence arises from the intrinsic graphene structure and requires the presence of Rashba spin-orbit interaction. The different group velocities depend on the chirality of the electronic states, mimicking the light polarization dependence of the group velocities in optical birefringent materials. In circular regions containing large Rashba interaction and reversed charge density (Veselago lenses), we predict the formation of sets of double caustics and cusps, where the spacing between the two different chiral cusps is proportional to the strength of the Rashba interaction in the system. Supported by NSF MWN/CIAM and NSF PIRE.

  8. Nonlocal spin-confinement of electrons in graphene with proximity exchange interaction

    NASA Astrophysics Data System (ADS)

    Ang, Yee Sin; Liang, Shi-Jun; Ooi, Kelvin J. A.; Zhang, Chao; Ma, Zhongshui; Ang, Lay Kee

    In graphene-magnetic-insulator hybrid structure such as graphene-Europium-oxide (EuO-G), proximity induced exchange interaction opens up a spin-dependent bandgap and spin splitting in the Dirac band. We study the bound state formation in a hetero-interface composed of EuO-G. We theoretically predict a remarkable nonlocal spin-confinement effect in EuO-G and show that spin-polarized quasi-1D electron interface state can be generated in a magnetic-field-free channel. Quasiparticle transport mediated by the interface state can be efficiently controlled by the channel width and electrostatic gating. Our results suggest a pathway to further reduce the dimensionality of graphene quasiparticles from 2D to 1D, thus offering an exciting graphene-based platform for the search of exotic 1D physics and spintronic applications.

  9. Symmetry analysis of phosphorene: electronic structure with spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Li, Pengke; Appelbaum, Ian; Appelbaum's Group Team

    2015-03-01

    We present a symmetry analysis of electronic band structure including spin-orbit interaction close to the insulating gap edge in monolayer black phosphorus (``phosphorene''). Expressions for energy dispersion relation and spin-dependent eigenstates for electrons and holes are found via simplification of a perturbative expansion in wave vector k away from the zone center using elementary group theory. Importantly, we expose the underlying symmetries giving rise to substantial anisotropy in optical absorption, charge, and spin transport properties, and reveal the mechanism responsible for valence band distortion and possible lack of a true direct gap. We discovered that, spin flip processes are decoupled by symmetry from flexural phonons, allowing us to predict a spin lifetime comparable to bulk Si, vastly greater than graphene.

  10. Identification of Weakly Interacting Massive Particles Through a Combined Measurement of Axial and Scalar Couplings

    NASA Astrophysics Data System (ADS)

    Bertone, G.; Cerdeño, D. G.; Collar, J. I.; Odom, B.

    2007-10-01

    We study the prospects for detecting weakly interacting massive particles (WIMPs) in a number of phenomenological scenarios, with a detector composed of a target simultaneously sensitive to both spin-dependent and spin-independent couplings, as is the case of COUPP (Chicagoland Observatory for Underground Particle Physics). First, we show that sensitivity to both couplings optimizes chances of initial WIMP detection. Second, we demonstrate that, in case of detection, a comparison of the signal on two complementary targets, such as in COUPP CF3I and C4F10 bubble chambers, allows a significantly more precise determination of the dark matter axial and scalar couplings. This strategy would provide crucial information on the nature of the WIMPs and possibly allow discrimination between neutralino and Kaluza-Klein dark matter.

  11. Interface states in two-dimensional electron systems with spin-orbital interaction.

    PubMed

    Sukhanov, Aleksei A; Sablikov, Vladimir A

    2011-10-05

    Interface states at a boundary between regions with different spin-orbit interactions (SOIs) in two-dimensional (2D) electron systems are investigated within the one-band effective mass method with generalized boundary conditions for envelope functions. We have found that the interface states unexpectedly exist even if the effective interface potential equals zero. Depending on the system parameters, the energy of these states can lie in either or both forbidden and conduction bands of bulk states. The interface states have chiral spin texture similar to that of the edge states in 2D topological insulators. However, their energy spectrum is more sensitive to the interfacial potential, the largest effect being produced by the spin-dependent component of the interfacial potential. We have also studied the size quantization of the interface states in a strip of 2D electron gas with SOI and found an unusual (non-monotonic) dependence of the quantization energy on the strip width.

  12. Separating hyperfine from spin-orbit interactions in organic semiconductors by multi-octave magnetic resonance using coplanar waveguide microresonators

    SciTech Connect

    Joshi, G.; Miller, R.; Ogden, L.; Kavand, M.; Jamali, S.; Ambal, K.; Malissa, H.; Boehme, C.; Venkatesh, S.; Schurig, D.; Lupton, J. M.

    2016-09-05

    Separating the influence of hyperfine from spin-orbit interactions in spin-dependent carrier recombination and dissociation processes necessitates magnetic resonance spectroscopy over a wide range of frequencies. We have designed compact and versatile coplanar waveguide resonators for continuous-wave electrically detected magnetic resonance and tested these on organic light-emitting diodes. By exploiting both the fundamental and higher-harmonic modes of the resonators, we cover almost five octaves in resonance frequency within a single setup. The measurements with a common π-conjugated polymer as the active material reveal small but non-negligible effects of spin-orbit interactions, which give rise to a broadening of the magnetic resonance spectrum with increasing frequency.

  13. Dark matter search with PICASSO

    NASA Astrophysics Data System (ADS)

    Zacek, V.; Archambault, S.; Behnke, E.; Behnke, J.; Das, M.; Davour, A.; Debris, F.; Dhungana, N.; Farine, J.; Gagnebin, S.; Hinnefeld, H.; Jackson, C. M.; Kamaha, A.; Krauss, C.; Lafrenière, M.; Laurin, M.; Lawson, I.; Lévy, C.; Lessard, L.; Levine, I.; Marlisov, D.; Martin, J.-P.; Kumaratunga, S.; MacDonald, R.; Mitra, P.; Nadeau, P.; Noble, A.; Piro, M.-C.; Plante, A.; Podviyaniuk, R.; Pospisil, S.; Seth, S.; Scallon, O.; Starinski, N.; Stekl, I.; Vander Werf, N.; Wichoski, U.; Xie, T.

    2012-07-01

    PICASSO at SNOLAB searches primarily for spin-dependent WIMP interactions on 19F using the superheated droplet technique. This technique is based on the bubble chamber principle, where phase transitions in superheated liquid droplets can be triggered by WIMP induced nuclear recoils. The physics of the detection process allows a highly efficient suppression of backgrounds from cosmic muons, γ- and β-rays. We will discuss qualitatively recent progress in PICASSO and its sensitivity reach for spin-dependent and spin-independent WIMP searches.

  14. Characterization of the effective NN interaction in the nuclear medium through

    NASA Astrophysics Data System (ADS)

    Jiang, Kehan

    An investigation of the 6- T = 0 and 1 transitions in 28Si( p->,p-> ' )28Si was undertaken to characterize modifications to the effective nucleon-nucleon (NN) interaction in the nuclear medium. This experiment (E395) was an extension to E353, and involved measurements of the in-plane polarization transfer coefficients DLL,DLS',DSL ', , and DSS' of the 28Si 6- transitions at a bombarding energy near 200 MeV. The measurements were made at the Indiana University Cyclotron Facility using the K600 spectrometer with its focal plane detectors and polarimeter. A full set of polarization transfer observables allowed us to study further the spin-dependent parts of the effective NN interaction. The distorted-wave impulse approximation (DWIA) was employed to calculate the amplitudes for the 28Si 6- transitions and to evalulate the scattering observables. These transitions are called ``stretched'' because their structures, which are well described by assuming a single 1f7/21d- 15/2 particle-hole configuration, involve the maximal alignment of the particle and hole total spins. Constraints on the transition form factors were taken from electron scattering measurements. The distorted waves were calculated from a microscopic optical potential that was folded over the nuclear density using the effective NN interaction. This gave us consistency between the distortions and the effective NN interaction in the calculation. Two kinds of effective NN interactions were investigated. The first was based on a one-boson-exchange model in which the 2π exchange for the intermediate-range attraction in the nuclear force was simplified to a fictitious σ meson. It included Pauli blocking, nuclear binding, and relativistic medium effects. The second implemented a microscopic 2π exchange for the intermediate-range attraction, while still using one- boson-exchange for other parts of the nuclear force. In addition to Pauli blocking, nuclear binding, and relativistic effects, the

  15. Inter-rater reliability between nurses for a new paediatric triage system based primarily on vital parameters: the Paediatric Triage Instrument (PETI)

    PubMed Central

    Karjala, Jaana; Eriksson, Staffan

    2017-01-01

    Introduction The major paediatric triage systems are primarily based on flow charts involving signs and symptoms for orientation and subjective estimates of the patient's condition. In contrast, the 4-level Paediatric Triage Instrument (PETI) is primarily based on vital parameters and was developed exclusively for paediatric triage in patients with medical symptoms. The aim of this study was to assess the inter-rater reliability of this triage system in children when used by nurses. Methods A design was employed in which triage was performed simultaneously and independently by a research nurse and an emergency department (ED) nurse using the PETI. All patients aged ≤12 years who presented at the ED with a medical symptom were considered eligible for participation. Results The 89 participants exhibited a median age of 2 years and were triaged by 28 different nurses. The inter-rater reliability between nurses calculated with the quadratic-weighted κ was 0.78 (95% CI 0.67 to 0.89); the linear-weighted κ was 0.67 (95% CI 0.56 to 0.80) and the unweighted κ was 0.59 (95% CI 0.44 to 0.73). For the patients aged <1, 1–3 and >3 years, the quadratic-weighted κ values were 0.67 (95% CI 0.39 to 0.94), 0.86 (95% CI 0.75 to 0.97) and 0.73 (95% CI 0.49 to 0.97), respectively. The median triage duration was 6 min. Conclusions The PETI exhibited substantial reliability when used in children aged ≤12 years and almost perfect reliability among children aged 1–3 years. Moreover, rapid application of the PETI was demonstrated. This study has some limitations, including sample size and generalisability, but the PETI exhibited promise regarding reliability, and the next step could be either a larger reliability study or a validation study. PMID:28235966

  16. The inflammatory response seen when human omental adipose tissue explants are incubated in primary culture is not dependent upon albumin and is primarily in the nonfat cells.

    PubMed

    Fain, John N; Cheema, Paramjeet; Tichansky, David S; Madan, Atul K

    2010-01-21

    The present studies were designed to investigate the changes in gene expression during in vitro incubation of human visceral omental adipose tissue explants as well as fat cells and nonfat cells derived from omental fat. Adipose tissue was obtained from extremely obese women undergoing bariatric surgery. Explants of the tissue as well as fat cells and the nonfat cells derived by digestion with collagenase were incubated for 20 minutes to 48 h. The expression of interleukin 1beta [IL-1beta], tumor necrosis factor alpha [TNFalpha], interleukin 8 [IL-8], NFkappaB(1)p50 subunit, hypoxia-inducible factor 1alpha [HIF1alpha], omentin/intelectin, and 11beta-hydroxysteroid dehydrogenase 1 [11beta-HSD1] mRNA were measured by qPCR as well as the release of IL-8 and TNFalpha. There was an inflammatory response at 2 h in explants of omental adipose tissue that was reduced but not abolished in the absence of albumin from the incubation buffer for IL-8, IL-1beta and TNFalpha. There was also an inflammatory response with regard to upregulation of HIF1alpha and NFkappaB1 gene expression that was unaffected whether albumin was present or absent from the medium. In the nonfat cells derived by a 2 h collagenase digestion of omental fat there was an inflammatory response comparable but not greater than that seen in tissue. The exception was HIF1alpha where the marked increase in gene expression was primarily seen in intact tissue. The inflammatory response was not seen with respect to omentin/intelectin. Over a subsequent 48 h incubation there was a marked increase in IL-8 mRNA expression and IL-8 release in adipose tissue explants that was also seen to the same extent in the nonfat cells incubated in the absence of fat cells. The marked inflammatory response seen when human omental adipose tissue is incubated in vitro is reduced but not abolished in the presence of albumin with respect to IL-1beta, TNFalpha, IL-8, and is primarily in the nonfat cells of adipose tissue.

  17. The inflammatory response seen when human omental adipose tissue explants are incubated in primary culture is not dependent upon albumin and is primarily in the nonfat cells

    PubMed Central

    2010-01-01

    Background The present studies were designed to investigate the changes in gene expression during in vitro incubation of human visceral omental adipose tissue explants as well as fat cells and nonfat cells derived from omental fat. Methods Adipose tissue was obtained from extremely obese women undergoing bariatric surgery. Explants of the tissue as well as fat cells and the nonfat cells derived by digestion with collagenase were incubated for 20 minutes to 48 h. The expression of interleukin 1β [IL-1β], tumor necrosis factor α [TNFα], interleukin 8 [IL-8], NFκB1p50 subunit, hypoxia-inducible factor 1α [HIF1α], omentin/intelectin, and 11β-hydroxysteroid dehydrogenase 1 [11β-HSD1] mRNA were measured by qPCR as well as the release of IL-8 and TNFα. Results There was an inflammatory response at 2 h in explants of omental adipose tissue that was reduced but not abolished in the absence of albumin from the incubation buffer for IL-8, IL-1β and TNFα. There was also an inflammatory response with regard to upregulation of HIF1α and NFκB1 gene expression that was unaffected whether albumin was present or absent from the medium. In the nonfat cells derived by a 2 h collagenase digestion of omental fat there was an inflammatory response comparable but not greater than that seen in tissue. The exception was HIF1α where the marked increase in gene expression was primarily seen in intact tissue. The inflammatory response was not seen with respect to omentin/intelectin. Over a subsequent 48 h incubation there was a marked increase in IL-8 mRNA expression and IL-8 release in adipose tissue explants that was also seen to the same extent in the nonfat cells incubated in the absence of fat cells. Conclusion The marked inflammatory response seen when human omental adipose tissue is incubated in vitro is reduced but not abolished in the presence of albumin with respect to IL-1β, TNFα, IL-8, and is primarily in the nonfat cells of adipose tissue. PMID:20145729

  18. The amino-terminal fusion domain peptide of human immunodeficiency virus type 1 gp41 inserts into the sodium dodecyl sulfate micelle primarily as a helix with a conserved glycine at the micelle-water interface.

    PubMed Central

    Chang, D K; Cheng, S F; Chien, W J

    1997-01-01

    A peptide based on the N-terminal fusion domain of gp41 of human immunodeficiency virus type 1 (HIV-1) and its tryptophan analog were synthesized to examine the secondary structure in the micellar environment. Nuclear magnetic resonance (NMR), circular dichroism and electron paramagnetic resonance experiments indicated that the gp41 fusion peptide inserted into the micelle primarily as a helix (59%), with substantial beta-structure (26.7%). Deep penetration of the peptide into the apolar hydrocarbon core was supported by the results of fluorescence experiments in which the tryptophan analog exhibited a blue shift of about 30 nm in the presence of a sodium dodecyl sulfate micelle, in 1,2-dimyristoyl-rac-glycero-3-phosphocholine, and in 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine vesicular solutions. The results of spin label-attenuated 1H resonance experiments show that the region C-terminal to G16, which contains a turn structure, exhibited substantial interaction with the micelle, suggesting that it lies on the surface of micelle. Molecular simulation based on data from NMR experiments revealed a flexible hinge at residues 15 and 16 (alanine and glycine, respectively) from the N terminus of the peptide located at the micelle-solution interface. The highly conserved A15-G16 dipeptide may play a role in the function of fusion domain of HIV-1 envelope glycoprotein. PMID:9261381

  19. Understanding the Goals of Everyday Instrumental Actions Is Primarily Linked to Object, Not Motor-Kinematic, Information: Evidence from fMRI

    PubMed Central

    Nicholson, Toby; Roser, Matt; Bach, Patric

    2017-01-01

    Prior research conceptualised action understanding primarily as a kinematic matching of observed actions to own motor representations but has ignored the role of object information. The current study utilized fMRI to identify (a) regions uniquely involved in encoding the goal of others’ actions, and (b) to test whether these goal understanding processes draw more strongly on regions involved in encoding object semantics or movement kinematics. Participants watched sequences of instrumental actions while attending to either the actions’ goal (goal task), the movements performed (movement task) or the objects used (object task). The results confirmed, first, a unique role of the inferior frontal gyrus, middle temporal gyrus and medial frontal gyrus in action goal understanding. Second, they show for the first time that activation in the goal task overlaps directly with object- but not movement-related activation. Moreover, subsequent parametric analyses revealed that movement-related regions become activated only when goals are unclear, or observers have little action experience. In contrast to motor theories of action understanding, these data suggest that objects—rather than movement kinematics—carry the key information about others’ actions. Kinematic information is additionally recruited when goals are ambiguous or unfamiliar. PMID:28081175

  20. Bacterial diversity shift determined by different diets in the gut of the spotted wing fly Drosophila suzukii is primarily reflected on acetic acid bacteria.

    PubMed

    Vacchini, Violetta; Gonella, Elena; Crotti, Elena; Prosdocimi, Erica M; Mazzetto, Fabio; Chouaia, Bessem; Callegari, Matteo; Mapelli, Francesca; Mandrioli, Mauro; Alma, Alberto; Daffonchio, Daniele

    2017-04-01

    The pivotal role of diet in shaping gut microbiota has been evaluated in different animal models, including insects. Drosophila flies harbour an inconstant microbiota among which acetic acid bacteria (AAB) are important components. Here, we investigated the bacterial and AAB components of the invasive pest Drosophila suzukii microbiota, by studying the same insect population separately grown on fruit-based or non-fruit artificial diet. AAB were highly prevalent in the gut under both diets (90 and 92% infection rates with fruits and artificial diet respectively). Fluorescent in situ hybridization and recolonization experiments with green fluorescent protein (Gfp)-labelled strains showed AAB capability to massively colonize insect gut. High-throughput sequencing on 16S rRNA gene indicated that the bacterial microbiota of guts fed with the two diets clustered separately. By excluding AAB-related OTUs from the analysis, insect bacterial communities did not cluster separately according to the diet, suggesting that diet-based diversification of the community is primarily reflected on the AAB component of the community. Diet influenced also AAB alpha-diversity, with separate OTU distributions based on diets. High prevalence, localization and massive recolonization, together with AAB clustering behaviour in relation to diet, suggest an AAB role in the D. suzukii gut response to diet modification. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.