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Sample records for primarily spin-dependent interactions

  1. 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.

  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. 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.

  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. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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).

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

    SciTech Connect

    Marcos, Cristina; Peiró, Miguel; Robles, Sandra E-mail: miguel.peiro@uam.es

    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.

  15. 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.

  16. 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

  17. 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}.

  18. 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}.

  19. 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.

  20. 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.

  1. 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}.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  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. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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).

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. Compton scattering in strong magnetic fields: Spin-dependent influences at the cyclotron resonance

    NASA Astrophysics Data System (ADS)

    Gonthier, Peter L.; Baring, Matthew G.; Eiles, Matthew T.; Wadiasingh, Zorawar; Taylor, Caitlin A.; Fitch, Catherine J.

    2014-08-01

    The quantum electrodynamical (QED) process of Compton scattering in strong magnetic fields is commonly invoked in atmospheric and inner magnetospheric models of x-ray and soft gamma-ray emission in high-field pulsars and magnetars. A major influence of the field is to introduce resonances at the cyclotron frequency and its harmonics, where the incoming photon accesses thresholds for the creation of virtual electrons or positrons in intermediate states with excited Landau levels. At these resonances, the effective cross section typically exceeds the classical Thomson value by over 2 orders of magnitude. Near and above the quantum critical magnetic field of 44.13 TeraGauss, relativistic corrections must be incorporated when computing this cross section. This profound enhancement underpins the anticipation that resonant Compton scattering is a very efficient process in the environs of highly magnetized neutron stars. This paper presents formalism for the QED magnetic Compton differential cross section valid for both subcritical and supercritical fields, yet restricted to scattered photons that are below pair creation threshold. Calculations are developed for the particular case of photons initially propagating along the field, and in the limit of zero vacuum dispersion, mathematically simple specializations that are germane to interactions involving relativistic electrons frequently found in neutron star magnetospheres. This exposition of relativistic, quantum, magnetic Compton cross sections treats electron spin dependence fully, since this is a critical feature for describing the finite decay lifetimes of the intermediate states. Such lifetimes are introduced to truncate the resonant cyclotronic divergences via standard Lorentz profiles. The formalism employs both the traditional Johnson and Lippmann (JL) wave functions and the Sokolov and Ternov (ST) electron eigenfunctions of the magnetic Dirac equation. The ST states are formally correct for self

  15. 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.

  16. 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.

  17. 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.

  18. 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).

  19. 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

  20. 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.

  1. 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.

  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 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

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. {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.

  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. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Electron-spin-dependent terahertz light transport in spintronic-plasmonic media.

    PubMed

    Chau, K J; Johnson, Mark; Elezzabi, A Y

    2007-03-30

    In this Letter, we demonstrate that electron spin can influence near-field mediated light propagation through a dense ensemble of subwavelength bimetallic ferromagnetic/nonmagnetic microparticles. In particular, we show that ferromagnetic particles coated with nonmagnetic metal nanolayers exhibit an enhanced magnetic field controlled attenuation of the electromagnetic field propagated through the sample. The mechanism is related to dynamic, electromagnetically induced electron spin accumulation in the nonmagnet. The discovery of an electron spin phenomenon in the light interaction with metallic particles opens the door to the marriage of spintronic and plasmonic technologies and could pave the way for the development of light-based devices that exploit the electron spin state.

  10. 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.

  11. 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...

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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...

  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. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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. .

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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}.

  6. 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.

  7. 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

  8. 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.

  9. 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'…

  10. 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)...

  11. 12 CFR 225.127 - Investment in corporations or projects designed primarily to promote community welfare.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., 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)...

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

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...-income persons, small businesses, or nonprofit corporations to help achieve community development. (g... 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 §...

  13. 12 CFR 225.127 - Investment in corporations or projects designed primarily to promote community welfare.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., 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)...

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

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...-income persons, small businesses, or nonprofit corporations to help achieve community development. (g... 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 §...

  15. 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.

  16. 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.

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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…

  3. 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…

  4. 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.

  5. 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.…

  6. 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

  7. 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.

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. Direct healthcare costs of selected diseases primarily or partially transmitted by water.

    PubMed

    Collier, S A; Stockman, L J; Hicks, L A; Garrison, L E; Zhou, F J; Beach, M J

    2012-11-01

    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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  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. 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.

  10. 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).

  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... INDIVIDUALS WITH DISABILITIES (ADA) Provision of Service § 37.171 Equivalency requirement for demand responsive service operated by private entities not primarily engaged in the business of transporting...

  12. 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...

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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...

  6. 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…

  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

    ... 49 Transportation 1 2014-10-01 2014-10-01 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...

  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

    ... 49 Transportation 1 2013-10-01 2013-10-01 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...

  9. 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

    ... 49 Transportation 1 2014-10-01 2014-10-01 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 37.107 - 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...

  11. 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...

  12. 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 +}.

  13. 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.

  14. 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.

  15. 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).

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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

  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. 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.

  14. 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.

  15. 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…

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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...

  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. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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).

  19. 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.

  20. APOLLON at DESY: Spin-dependent photoproduction of charm

    SciTech Connect

    Miller, C. A.

    1998-01-20

    APOLLON is a proposal to measure the polarization asymmetry of J/{psi} photoproduction in a fixed target experiment at HERA in an effort to provide information on the gluon spin distribution in the nucleon. Inelastic production will be identified via the {mu}{sup +}{mu}{sup -} decay channel, resulting in a statistical precision of {delta}A=0.05 in a 12 month run. In the LO CSM, the corresponding precision in {delta}G(x)/G(x) is 0.15 at x{approx}0.4.

  1. 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.

  2. "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…

  3. 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.

  4. 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.

  5. 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).

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  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. 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.

  17. 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.

  18. Separating hyperfine from spin-orbit interactions in organic semiconductors by multi-octave magnetic resonance using coplanar waveguide microresonators

    NASA Astrophysics Data System (ADS)

    Joshi, G.; Miller, R.; Ogden, L.; Kavand, M.; Jamali, S.; Ambal, K.; Venkatesh, S.; Schurig, D.; Malissa, H.; Lupton, J. M.; Boehme, C.

    2016-09-01

    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.

  19. High mobility group protein number17 cross-links primarily to histone H2A in the reconstituted HMG 17 - nucleosome core particle complex

    SciTech Connect

    Cook, G.R.; Yau, P.; Yasuda, H.; Traut, R.R.; Bradbury, E.M.

    1986-05-01

    The neighbor relationship of lamb thymus High Mobility Group (HMG) protein 17 to native HeLa nucleosome core particle histones in the reconstituted complex has been studied. /sup 125/I-labeled HMG 17 was cross-linking to core histones using the protein-protein cross-linking reagent 2-iminothiolane. Specific cross-linked products were separated on a two-dimensional Triton-acid-urea/SDS gel system, located by autoradiography, excised and quantified. Disulfide bonds in the cross links were then cleaved and the protein constituents were identified by SDS gel electrophoresis. HMG 17 cross-linked primarily to histone H2A while lower levels of cross-linking occurred between HMG 17 and the other histones. In contrast, cross-linking between two HMG 17 molecules bound on the same nucleosome was relatively rare. It is concluded that the same nucleosome was relatively rare. It is concluded that H2A comprises part of the HMG 17 binding site but that HMG 17 is sufficiently elongated and mobile to permit cross-linking to the other histones and to a second HMG 17 molecule. These results are in agreement with the current model for the structure of the nucleosome and the proposed binding sites for HMG 17.

  20. An Internally Consistent Thermodynamic Model for the System CaO-MgO-Al2O3-SiO2 Derived Primarily from Phase Equilibrium Data.

    PubMed

    Gasparik

    2000-01-01

    An internally consistent thermodynamic model for the subsolidus system CaO-MgO-Al2O3-SiO2 (CMAS) was developed and refined using primarily data from phase equilibrium experiments. The solution properties of pyroxenes and garnet were approximated with an ionic model, with independent mixing on adjacent crystallographic sites. This approach simplified the calculation of phase relations by allowing sequential calculation of the site occupancies. Enthalpy, entropy, and volume differences, nominally at 970 K, were derived for all participating phases by matching as closely as possible the experimentally observed phase relations. Although thermochemical measurements were not used directly in the refinement, the results were continuously monitored and compared with the thermochemical data to achieve a close match. The new model can be used to calculate phase diagrams for the CMAS system and its subsystems in the whole pressure range of the upper mantle. Simple empirical corrections for the effects of Na, Fe, Cr, etc., could potentially be introduced to make the model applicable to the thermobarometry of chemically complex mantle materials. Application of the new model to garnet lherzolite xenoliths from northern Lesotho and garnet peridotites from Norway supports the proposals for higher temperatures of the continental lithosphere.

  1. STO Feeder Cells Are Useful for Propagation of Primarily Cultured Human Deciduous Dental Pulp Cells by Eliminating Contaminating Bacteria and Promoting Cellular Outgrowth.

    PubMed

    Murakami, Tomoya; Saitoh, Issei; Inada, Emi; Kurosawa, Mie; Iwase, Yoko; Noguchi, Hirofumi; Terao, Yutaka; Yamasaki, Youichi; Hayasaki, Haruaki; Sato, Masahiro

    2013-12-30

    STO feeder cells, a line established from mouse SIM embryonic fibroblasts, have been frequently used for establishing embryonic stem cells and maintaining them in an undifferentiated state. There are some reports demonstrating that fibroblastic cells have the ability to phagocytose Gram-positive bacterium (e.g., streptococci and staphylococci). In this study, we examined the possibility that STO cells could phagocytose Streptococcus mutans (a bacteria causing tooth decay), which always contaminates cultures of primarily isolated human deciduous dental pulp cells (HDDPCs). Simple cultivation of the primary HDDPCs in the absence of STO cells allowed S. mutans to massively propagate in the medium, thus leading to an opaque medium. In contrast, there was no bacterial contamination in the cultures containing mitomycin C (MMC)-inactivated STO cells. Furthermore, STO cells indicated bacterial phagocytic activity under fluorescent microscopy with the dye pHrodo. Besides removal of contaminating bacteria, STO feeder cells allowed the HDDPCs to spread out. These data suggest that MMC-treated STO cells can be useful for propagation of HDDPCs by eliminating contaminating bacteria and by promoting cellular outgrowth.

  2. Effects of the Start For Life treatment on physical activity in primarily African American preschool children of ages 3-5 years.

    PubMed

    Annesi, James J; Smith, Alice E; Tennant, Gisèle A

    2013-01-01

    In U.S. children of ages 2-5 years, combined overweight and obesity has increased to 21%, with African American children of this age range highest at 26%. Lack of physical activity is highly predictive of overweight and obesity in children. Preschools may be a useful point for intervention. An innovative preschool physical activity treatment (Start For Life) was developed based on principles of social cognitive and self-efficacy theory. It incorporated 30 minutes daily of highly structured physical activity with behavioral and self-regulatory skills training (e.g. goal setting, self-monitoring, productive self-talk) interspersed. Data obtained from accelerometry was used to contrast physical activity outputs during the preschool day in the Start For Life condition (n = 202) with a usual-care control condition (n = 136). After controlling for age and sex of the primarily African American participants (M age = 4.7 years), changes over eight weeks in moderate-to-vigorous and vigorous physical activity were significant, and significantly more favorable in the Start For Life group; F(1, 344) = 4.98, p = .026 and F(1, 344) = 3.60, p = .058, respectively. Start For Life was associated with a weekly increase in moderate-to-vigorous physical activity of approximately 40 minutes. After sufficient replications that better account for different sample types, parental effects and physical activity outside of the school day, and long-term effects, widespread dissemination may be considered.

  3. Hutchinson–Gilford progeria mutant lamin A primarily targets human vascular cells as detected by an anti-Lamin A G608G antibody

    PubMed Central

    McClintock, Dayle; Gordon, Leslie B.; Djabali, Karima

    2006-01-01

    Hutchinson–Gilford progeria syndrome (HGPS; Online Mendelian Inheritance in Man accession no. 176670) is a rare disorder that is characterized by segmental premature aging and death between 7 and 20 years of age from severe premature atherosclerosis. Mutations in the LMNA gene are responsible for this syndrome. Approximately 80% of HGPS cases are caused by a G608 (GGC→GGT) mutation within exon 11 of LMNA, which elicits a deletion of 50 aa near the C terminus of prelamin A. In this article, we present evidence that the mutant lamin A (progerin) accumulates in the nucleus in a cellular age-dependent manner. In human HGPS fibroblast cultures, we observed, concomitantly to nuclear progerin accumulation, severe nuclear envelope deformations and invaginations preventable by farnesyltransferase inhibition. Nuclear alterations affect cell-cycle progression and cell migration and elicit premature senescence. Strikingly, skin biopsy sections from a subject with HGPS showed that the truncated lamin A accumulates primarily in the nuclei of vascular cells. This finding suggests that accumulation of progerin is directly involved in vascular disease in progeria. PMID:16461887

  4. Hutchinson-Gilford progeria mutant lamin A primarily targets human vascular cells as detected by an anti-Lamin A G608G antibody.

    PubMed

    McClintock, Dayle; Gordon, Leslie B; Djabali, Karima

    2006-02-14

    Hutchinson-Gilford progeria syndrome (HGPS; Online Mendelian Inheritance in Man accession no. 176670) is a rare disorder that is characterized by segmental premature aging and death between 7 and 20 years of age from severe premature atherosclerosis. Mutations in the LMNA gene are responsible for this syndrome. Approximately 80% of HGPS cases are caused by a G608 (GGC-->GGT) mutation within exon 11 of LMNA, which elicits a deletion of 50 aa near the C terminus of prelamin A. In this article, we present evidence that the mutant lamin A (progerin) accumulates in the nucleus in a cellular age-dependent manner. In human HGPS fibroblast cultures, we observed, concomitantly to nuclear progerin accumulation, severe nuclear envelope deformations and invaginations preventable by farnesyltransferase inhibition. Nuclear alterations affect cell-cycle progression and cell migration and elicit premature senescence. Strikingly, skin biopsy sections from a subject with HGPS showed that the truncated lamin A accumulates primarily in the nuclei of vascular cells. This finding suggests that accumulation of progerin is directly involved in vascular disease in progeria.

  5. The Arabidopsis flowering-time gene LUMINIDEPENDENS is expressed primarily in regions of cell proliferation and encodes a nuclear protein that regulates LEAFY expression.

    PubMed

    Aukerman, M J; Lee, I; Weigel, D; Amasino, R M

    1999-04-01

    Mutations in the LUMINIDEPENDENS (LD) gene of Arabidopsis thaliana (L.) Heynh. (Arabidopsis) confer a late-flowering phenotype, indicating that LD normally functions to promote the floral transition. RNA and protein blot analyses, along with the analysis of transgenic plants containing a fusion between a genomic fragment of LD and the reporter gene uidA (GUS), indicate that LD is expressed primarily ipical proliferative regions of the shoot and root, including the shoot apical meristem and leaf primordia. Subcellular localization studies indicate that LD is a nuclear protein, consistent with its previously proposed transcriptional regulatory role. We have also found that in an apetala1 cauliflower (ap1 cal) background the ld mutation converts the reproductive shoot apex to a more vegetative state, a phenotype that is similar to that seen for the leafy (lfy) mutant. Furthermore, in situ hybridization analysis indicates that LFY levels are drastically reduced at the apex of ld ap1 cal plants after bolting. These data are consistent with the idea that at least one function of LD is to participate in the regulation of LFY.

  6. Abnormalities in larvae from the once-largest Pacific herring population in Washington State result primarily from factors independent of spawning location

    USGS Publications Warehouse

    Hershberger, P.K.; Elder, N.E.; Wittouck, J.; Stick, K.; Kocan, R.M.

    2005-01-01

    Among larvae from populations of Pacific herring Clupea pallasii in Washington State those from Cherry Point have consistently demonstrated abnormalities indicative of distress, including low weights and lengths at hatch, increased prevalences of skeletal abnormalities, and shorter survival times in food deprivation studies. The biomass of adult, prespawn Pacific herring at Cherry Point declined from 13,606 metric tons in 1973 to a record low 733 metric tons in 2000. However, correlation of larval abnormalities with adult recruitment was weak, indicating that the larval abnormalities did not directly cause the decline. Larval abnormalities originated primarily from factors independent of conditions at the spawning location because they were not reproduced by incubation of foreign zygotes along the Cherry Point shoreline but were reproduced after the development of indigenous zygotes in controlled laboratory conditions. Although the precise cause of the abnormalities was not determined, recent zoographic trends in elevated natural mortality among adult Pacific herring and resulting reduced age structures may be involved. ?? Copyright by the American Fisheries Society 2005.

  7. Human milk miRNAs primarily originate from the mammary gland resulting in unique miRNA profiles of fractionated milk

    PubMed Central

    Alsaweed, Mohammed; Lai, Ching Tat; Hartmann, Peter E.; Geddes, Donna T.; Kakulas, Foteini

    2016-01-01

    Human milk (HM) contains regulatory biomolecules including miRNAs, the origin and functional significance of which are still undetermined. We used TaqMan OpenArrays to profile 681 mature miRNAs in HM cells and fat, and compared them with maternal peripheral blood mononuclear cells (PBMCs) and plasma, and bovine and soy infant formulae. HM cells and PBMCs (292 and 345 miRNAs, respectively) had higher miRNA content than HM fat and plasma (242 and 219 miRNAs, respectively) (p < 0.05). A strong association in miRNA profiles was found between HM cells and fat, whilst PBMCs and plasma were distinctly different to HM, displaying marked inter-individual variation. Considering the dominance of epithelial cells in mature milk of healthy women, these results suggest that HM miRNAs primarily originate from the mammary epithelium, whilst the maternal circulation may have a smaller contribution. Our findings demonstrate that unlike infant formulae, which contained very few human miRNA, HM is a rich source of lactation-specific miRNA, which could be used as biomarkers of the performance and health status of the lactating mammary gland. Given the recently identified stability, uptake and functionality of food- and milk-derived miRNA in vivo, HM miRNA are likely to contribute to infant protection and development. PMID:26854194

  8. 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

  9. Salinity-induced inhibition of growth in the aquatic pteridophyte Azolla microphylla primarily involves inhibition of photosynthetic components and signaling molecules as revealed by proteome analysis.

    PubMed

    Thagela, Preeti; Yadav, Ravindra Kumar; Mishra, Vagish; Dahuja, Anil; Ahmad, Altaf; Singh, Pawan Kumar; Tiwari, Budhi Sagar; Abraham, Gerard

    2017-01-01

    Salinity stress causes adverse physiological and biochemical changes in the growth and productivity of a plant. Azolla, a symbiotic pteridophyte and potent candidate for biofertilizer due to its nitrogen fixation ability, shows reduced growth and nitrogen fixation during saline stress. To better understand regulatory components involved in salinity-induced physiological changes, in the present study, Azolla microphylla plants were exposed to NaCl (6.74 and 8.61 ds/m) and growth, photochemical reactions of photosynthesis, ion accumulation, and changes in cellular proteome were studied. Maximum dry weight was accumulated in control and untreated plant while a substantial decrease in dry weight was observed in the plants exposed to salinity. Exposure of the organism to different concentrations of salt in hydroponic conditions resulted in differential level of Na(+) and K(+) ion accumulation. Comparative analysis of salinity-induced proteome changes in A. microphylla revealed 58 salt responsive proteins which were differentially expressed during the salt exposure. Moreover, 42 % spots among differentially expressed proteins were involved in different signaling events. The identified proteins are involved in photosynthesis, energy metabolism, amino acid biosynthesis, protein synthesis, and defense. Downregulation of these key metabolic proteins appears to inhibit the growth of A. microphylla in response to salinity. Altogether, the study revealed that in Azolla, increased salinity primarily affected signaling and photosynthesis that in turn leads to reduced biomass.

  10. 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.

  11. Excretion of the dipeptidyl peptidase-4 inhibitor linagliptin in rats is primarily by biliary excretion and P-gp-mediated efflux.

    PubMed

    Fuchs, Holger; Runge, Frank; Held, Heinz-Dieter

    2012-04-11

    Linagliptin is a selective, competitive dipeptidyl peptidase-4 (DPP-4) inhibitor, recently approved in the USA, Japan and Europe for the treatment of type 2 diabetes. It has non-linear pharmacokinetics and, unlike other DPP-4 inhibitors, a largely non-renal excretion route. It was hypothesised that P-glycoprotein (P-gp)-mediated intestinal transport could influence linagliptin bioavailability, and might contribute to its elimination. Two studies evaluated the role of P-gp-mediated transport in the bioavailability and intestinal secretion of linagliptin in rats. In the bioavailability study, male Wistar rats received single oral doses of linagliptin, 1 or 15 mg/kg, plus either the P-gp inhibitor, zosuquidar trihydrochloride, or vehicle. For the intestinal secretion study, rats underwent bile duct cannulation, and urine, faeces, and bile were collected. At the end of the study, gut content was sampled. Inhibition of intestinal P-gp increased the bioavailability of orally administered linagliptin, indicating that this transport system plays a role in limiting the uptake of linagliptin from the intestine. This effect was dependent on linagliptin dose, and could play a role in its non-linear pharmacokinetics after oral dosing. Systemically available linagliptin was mainly excreted unchanged via bile (49% of i.v. dose), but some (12%) was also excreted directly into the gut independently of biliary excretion. Thus, direct excretion of linagliptin into the gut may be an alternative excretion route in the presence of liver and renal impairment. The primarily non-renal route of excretion is likely to be of benefit to patients with type 2 diabetes, who have a high prevalence of renal insufficiency.

  12. Quantity of dietary protein intake, but not pattern of intake, affects net protein balance primarily through differences in protein synthesis in older adults.

    PubMed

    Kim, Il-Young; Schutzler, Scott; Schrader, Amy; Spencer, Horace; Kortebein, Patrick; Deutz, Nicolaas E P; Wolfe, Robert R; Ferrando, Arny A

    2015-01-01

    To examine whole body protein turnover and muscle protein fractional synthesis rate (MPS) following ingestions of protein in mixed meals at two doses of protein and two intake patterns, 20 healthy older adult subjects (52-75 yr) participated in one of four groups in a randomized clinical trial: a level of protein intake of 0.8 g (1RDA) or 1.5 g·kg(-1)·day(-1) (∼2RDA) with uneven (U: 15/20/65%) or even distribution (E: 33/33/33%) patterns of intake for breakfast, lunch, and dinner over the day (1RDA-U, 1RDA-E, 2RDA-U, or 2RDA-E). Subjects were studied with primed continuous infusions of L-[(2)H5]phenylalanine and L-[(2)H2]tyrosine on day 4 following 3 days of diet habituation. Whole body protein kinetics [protein synthesis (PS), breakdown, and net balance (NB)] were expressed as changes from the fasted to the fed states. Positive NB was achieved at both protein levels, but NB was greater in 2RDA vs. 1RDA (94.8 ± 6.0 vs. 58.9 ± 4.9 g protein/750 min; P = 0.0001), without effects of distribution on NB. The greater NB was due to the higher PS with 2RDA vs. 1RDA (15.4 ± 4.8 vs. -18.0 ± 8.4 g protein/750 min; P = 0.0018). Consistent with PS, MPS was greater with 2RDA vs. 1RDA, regardless of distribution patterns. In conclusion, whole body net protein balance was greater with protein intake above recommended dietary allowance (0.8 g protein·kg(-1)·day(-1)) in the context of mixed meals, without demonstrated effects of protein intake pattern, primarily through higher rates of protein synthesis at whole body and muscle levels.

  13. The elevation of apoB in hypercholesterolemic patients is primarily attributed to the relative increase of apoB/Lp-PLA2

    PubMed Central

    Tellis, Constantinos C.; Moutzouri, Eliza; Elisaf, Moses; Wolfert, Robert L.; Tselepis, Alexandros D.

    2013-01-01

    Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a risk factor of cardiovascular disease. Plasma Lp-PLA2 is mainly associated with apolipoprotein (apo)B-containing lipoproteins, primarily with low density lipoproteins (LDLs). Importantly, only a proportion of circulating lipoproteins contain Lp-PLA2. We determined the plasma levels of Lp-PLA2-bound apoB (apoB/Lp-PLA2) in patients with primary hypercholesterolemia. The effect of simvastatin therapy was also addressed. The plasma apoB/Lp-PLA2 concentration in 50 normolipidemic controls and 53 patients with primary hypercholesterolemia at baseline and at 3 months posttreatment with simvastatin (40 mg/day) was determined by an enzyme-linked immunosorbent assay. The concentration of the apoB-containing lipoproteins that do not bind Lp-PLA2 [apoB/Lp-PLA2(−)] was calculated by subtracting the apoB/Lp-PLA2 from total apoB. The apoB/Lp-PLA2 levels were 3.6-fold higher, while apoB/Lp-PLA2(−) were 1.3-fold higher in patients compared with controls. After 3 months of simvastatin treatment apoB/Lp-PLA2 and apoB/Lp-PLA2(−) levels were reduced by 52% and 33%, respectively. The elevation in apoB-containing lipoproteins in hypercholesterolemic patients is mainly attributed to the relative increase in the proatherogenic apoB/Lp-PLA2, while simvastatin reduces these particles to a higher extent compared with apoB/Lp-PLA2(−). Considering that Lp-PLA2 is proatherogenic, the predominance of apoB/Lp-PLA2 particles in hypercholesterolemic patients may contribute to their higher atherogenicity and incidence of cardiovascular disease. PMID:24092915

  14. Neurotoxicity in Sri Lankan Russell's Viper (Daboia russelii) Envenoming is Primarily due to U1-viperitoxin-Dr1a, a Pre-Synaptic Neurotoxin.

    PubMed

    Silva, Anjana; Kuruppu, Sanjaya; Othman, Iekhsan; Goode, Robert J A; Hodgson, Wayne C; Isbister, Geoffrey K

    2017-01-01

    Russell's vipers are snakes of major medical importance in Asia. Russell's viper (Daboia russelii) envenoming in Sri Lanka and South India leads to a unique, mild neuromuscular paralysis, not seen in other parts of the world where the snake is found. This study aimed to identify and pharmacologically characterise the major neurotoxic components of Sri Lankan Russell's viper venom. Venom was fractionated using size exclusion chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). In vitro neurotoxicities of the venoms, fractions and isolated toxins were measured using chick biventer and rat hemidiaphragm preparations. A phospholipase A2 (PLA2) toxin, U1-viperitoxin-Dr1a (13.6 kDa), which constitutes 19.2 % of the crude venom, was isolated and purified using HPLC. U1-viperitoxin-Dr1a produced concentration-dependent in vitro neurotoxicity abolishing indirect twitches in the chick biventer nerve-muscle preparation, with a t 90 of 55 ± 7 min only at 1 μM. The toxin did not abolish responses to acetylcholine and carbachol indicating pre-synaptic neurotoxicity. Venom, in the absence of U1-viperitoxin-Dr1a, did not induce in vitro neurotoxicity. Indian polyvalent antivenom, at the recommended concentration, only partially prevented the neurotoxic effects of U1-viperitoxin-Dr1a. Liquid chromatography mass spectrometry analysis confirmed that U1-viperitoxin-Dr1a was the basic S-type PLA2 toxin previously identified from this venom (NCBI-GI: 298351762; SwissProt: P86368). The present study demonstrates that neurotoxicity following Sri Lankan Russell's viper envenoming is primarily due to the pre-synaptic neurotoxin U1-viperitoxin-Dr1a. Mild neurotoxicity observed in severely envenomed Sri Lankan Russell's viper bites is most likely due to the low potency of U1-viperitoxin-Dr1a, despite its high relative abundance in the venom.

  15. HIV/AIDS stigma among a sample of primarily African-American and Latino men who have sex with men social media users.

    PubMed

    Garett, Renee; Smith, Justin; Chiu, Jason; Young, Sean D

    2016-01-01

    The recent increase in social media use allows these technologies to rapidly reach communities with higher HIV prevalence, such as African-American and Latino men who have sex with men (MSM). However, no studies have looked at HIV/AIDS stigma among social media users from African-American and Latino MSM communities, or the association between stigma and social media use among these groups. This study sought to assess the level of HIV/AIDS stigma among a sample of social media-using African-American and Latino MSM from Los Angeles. A total of 112 (primarily African-American and Latino, n = 98, 88%) MSM Facebook users completed a survey on demographics, online social network use, and HIV/AIDS stigma. A composite stigma score was created by taking the cumulative score from a 15-item stigma questionnaire. Cumulative logistic models were used to assess the association between HIV/AIDS stigma and online social network use. In general, participants reported a low level of HIV/AIDS stigma (mean = 22.2/75, SD = 5.74). HIV/AIDS stigma composite score was significantly associated with increased time spent on online social networks each day (Adjusted odds ratios (AOR): 1.07, 95% CI: 1.00, 1.15). Among this diverse sample of MSM online social network users, findings suggest that HIV/AIDS stigma is associated with usage of social media. We discuss the implications of this work for future HIV prevention.

  16. The members of M20D peptidase subfamily from Burkholderia cepacia, Deinococcus radiodurans and Staphylococcus aureus (HmrA) are carboxydipeptidases, primarily specific for Met-X dipeptides.

    PubMed

    Jamdar, Sahayog N; Are, Venkata N; Navamani, Mallikarjunan; Kumar, Saurabh; Nagar, Vandan; Makde, Ravindra D

    2015-12-01

    Three members of peptidase family M20D from Burkholderia cepacia (BcepM20D; Uniprot accession no. A0A0F7GQ23), Deinococcus radiodurans R1 (DradM20D; Uniprot accession no. Q9RTP6) and Staphylococcus aureus (HmrA; Uniprot accession no. Q99Q45) were characterized in terms of their preference for various substrates. The results thus reveal that all the enzymes including HmrA lack endopeptidase as well as aminopeptidase activities and possess strong carboxypeptidase activity. Further, the amidohydrolase activity exerted on other substrates like N-Acetyl-Amino acids, N-Carbobenzoxyl-Amino acids and Indole acetic acid (IAA)-Amino acids is due to the ability of these enzymes to accommodate different types of chemical groups other than the amino acid at the S1 pocket. Further, data on peptide hydrolysis strongly suggests that all the three enzymes are primarily carboxydipeptidases exhibiting highest catalytic efficiency (kcat/Km 5-36 × 10(5) M(-1) s(-1)) for Met-X substrates, where -X could be Ala/Gly/Ser/Tyr/Phe/Leu depending on the source organism. The supportive evidence for the substrate specificities was also provided with the molecular docking studies carried out using structure of SACOL0085 and homology modelled structure of BcepM20D. The preference for different substrates, their binding at active site of the enzyme and possible role of these enzymes in recycling of methionine are discussed in this study.

  17. Global fits of the dark matter-nucleon effective interactions

    SciTech Connect

    Catena, Riccardo; Gondolo, Paolo E-mail: paolo.gondolo@utah.edu

    2014-09-01

    The effective theory of isoscalar dark matter-nucleon interactions mediated by heavy spin-one or spin-zero particles depends on 10 coupling constants besides the dark matter particle mass. Here we compare this 11-dimensional effective theory to current observations in a comprehensive statistical analysis of several direct detection experiments, including the recent LUX, SuperCDMS and CDMSlite results. From a multidimensional scan with about 3 million likelihood evaluations, we extract the marginalized posterior probability density functions (a Bayesian approach) and the profile likelihoods (a frequentist approach), as well as the associated credible regions and confidence levels, for each coupling constant vs dark matter mass and for each pair of coupling constants. We compare the Bayesian and frequentist approach in the light of the currently limited amount of data. We find that current direct detection data contain sufficient information to simultaneously constrain not only the familiar spin-independent and spin-dependent interactions, but also the remaining velocity and momentum dependent couplings predicted by the dark matter-nucleon effective theory. For current experiments associated with a null result, we find strong correlations between some pairs of coupling constants. For experiments that claim a signal (i.e., CoGeNT and DAMA), we find that pairs of coupling constants produce degenerate results.

  18. 13C-metabolic flux ratio and novel carbon path analyses confirmed that Trichoderma reesei uses primarily the respirative pathway also on the preferred carbon source glucose

    PubMed Central

    Jouhten, Paula; Pitkänen, Esa; Pakula, Tiina; Saloheimo, Markku; Penttilä, Merja; Maaheimo, Hannu

    2009-01-01

    of the TCA cycle. Conclusion High similarity between the biosynthetic pathways of amino acids in T. reesei and yeast S. cerevisiae was concluded. In vivo flux distributions confirmed that T. reesei uses primarily the respirative pathway also when growing on the repressive carbon source glucose in contrast to Saccharomyces cerevisiae, which substantially diminishes the respirative pathway flux under glucose repression. PMID:19874611

  19. PRP16, a DEAH-box RNA helicase, is recruited to the spliceosome primarily via its nonconserved N-terminal domain.

    PubMed Central

    Wang, Y; Guthrie, C

    1998-01-01

    Dynamic rearrangement of RNA structure is crucial for intron recognition and formation of the catalytic core during pre-mRNA splicing. Three of the splicing factors that contain sequence motifs characteristic of the DExD/DExH-box family of RNA-dependent ATPases (Prp16, Prp22, and the human homologue of Brr2) recently have been shown to unwind RNA duplexes in vitro, providing biochemical evidence that they may direct structural rearrangements on the spliceosome. Notably, however, the unwinding activity of these proteins is sequence nonspecific, raising the question of how their functional specificity is determined. Because the highly conserved DExD/DExH-box domain in these proteins is typically flanked by one or more nonconserved domains, we have tested the hypothesis that the nonconserved regions of Prp16 determine the functional specificity of the protein. We found that the nonconserved N-terminal domain of Prp16 is (1) essential for viability, (2) required for the nuclear localization of Prp16, and (3) capable of binding to the spliceosome specifically at the step of Prp16 function. Moreover, this domain can interact with the rest of the protein to allow trans-complementation. Based on these results, we propose that the spliceosomal target of the unwinding activity of Prp16, and possibly other DExD/DExH-box splicing factors as well, is defined by factors that specifically interact with the nonconserved domains of the protein. PMID:9769096

  20. The Community Structures of Prokaryotes and Fungi in Mountain Pasture Soils are Highly Correlated and Primarily Influenced by pH

    PubMed Central

    Lanzén, Anders; Epelde, Lur; Garbisu, Carlos; Anza, Mikel; Martín-Sánchez, Iker; Blanco, Fernando; Mijangos, Iker

    2015-01-01

    Traditionally, conservation and management of mountain pastures has been managed solely on the basis of visible biota. However, microorganisms play a vital role for the functioning of the soil ecosystem and, hence, pasture sustainability. Here, we studied the links between soil microbial (belowground) community structure (using amplicon sequencing of prokaryotes and fungi), other soil physicochemical and biological properties and, finally, a variety of pasture management practices. To this aim, during two consecutive years, we studied 104 environmental sites characterized by contrasting elevation, habitats, bedrock, and pasture management; located in or near Gorbeia Natural Park (Basque Country/Spain). Soil pH was found to be one of the most important factors in structuring soil microbial diversity. Interestingly, we observed a striking correlation between prokaryotic, fungal and macrofauna diversity, likely caused by interactions between these life forms. Further studies are needed to better understand such interactions and target the influence of different management practices on the soil microbial community, in face of the significant heterogeneity present. However, clearing of bushes altered microbial community structure, and in sites with calcareous bedrock also the use of herbicide vs. mechanical clearing of ferns. PMID:26640462

  1. PILRα binds an unknown receptor expressed primarily on CD56bright and decidual-NK cells and activates NK cell functions.

    PubMed

    Ophir, Yael; Duev-Cohen, Alexandra; Yamin, Rachel; Tsukerman, Pini; Bauman, Yoav; Gamliel, Moriya; Mandelboim, Ofer

    2016-07-05

    Natural Killer (NK) cells are innate immune lymphocytes specializing in recognition and killing of tumors and pathogens, using an array of activating and inhibitory receptors. NK inhibition is mediated by a large repertoire of inhibitory receptors, whereas a limited number of activating NK cell receptors execute NK cell activation. The ligands recognized by the activating receptors are stress-induced, pathogen derived, tumor specific and even self ligands. However, the full spectrum of NK cell receptors and ligands that control NK cell activity remains uncharacterized. Here we demonstrate that Paired Ig-Like type 2 Receptor Alpha (PILRα), binds a distinct human NK cell sub-population present in the peripheral blood and also in the decidua. We further demonstrate that the interaction of NK cells with PILRα expressing targets lead to elevated IFNγ secretion and cytotoxicity. In conclusion, we present here a novel NK activating ligand which binds and activates an unknown NK receptor expressed on a unique NK cell subset.

  2. Magnetoelectric subbands and eigenstates in the presence of Rashba and Dresselhaus spin-orbit interactions in a quantum wire

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, S.; Pramanik, S.; Cahay, M.

    2004-01-01

    We derive the eigenenergies and spin-dependent eigenstates of electrons in a quantum wire subjected to an external magnetic field. These are calculated in the presence of spin-orbit interactions arising from the Rashba (structural inversion asymmetry) and Dresselhaus (bulk inversion asymmetry) effects. We consider three cases: the external magnetic field is oriented (i) along the axis of the wire, (ii) perpendicular to the axis but parallel to the electric field associated with structural inversion asymmetry (Rashba effect), and (iii) perpendicular to the axis as well as this electric field. In all cases, the dispersions of the eigenenergies are non-parabolic and the subbands do not have a fixed spin quantization axis (meaning that the spin polarization of the electron is wavevector dependent). Except in the second case, the dispersion diagrams are also, in general, asymmetric about the energy axis.

  3. Effect of defects on phonons and the effective spin-spin interactions of an ultracold Penning-trap quantum simulator

    NASA Astrophysics Data System (ADS)

    McAneny, M.; Yoshimura, B.; Freericks, J. K.

    2013-10-01

    We generalize the analysis of the normal modes for a rotating ionic Coulomb crystal in a Penning trap to allow for inhomogeneities in the system. Our formal developments are completely general, but we choose to examine a crystal of Be+ ions with BeH+ defects to compare with current experimental efforts. We examine the classical phonon modes (both transverse and planar) and we determine the effective spin-spin interactions when the system is driven by an axial spin-dependent optical dipole force. We examine situations with up to approximately 15% defects. We find that most properties are not strongly influenced by the defects, indicating that the presence of a small number of defects will not significantly affect experiments.

  4. Dipolar interaction effects in the magnetic and magnetotransport properties of ordered nanoparticle arrays.

    PubMed

    Kechrakos, D; Trohidou, K N

    2008-06-01

    Assemblies of magnetic nanoparticles exhibit interesting physical properties arising from the competition of intraparticle dynamics and interparticle interactions. In ordered arrays of magnetic nanoparticles magnetostatic interparticle interactions introduce collective dynamics acting competitively to random anisotropy. Basic understanding, characterization and control of dipolar interaction effects in arrays of magnetic nanoparticles is an issue of central importance. To this end, numerical simulation techniques offer an indispensable tool. We report on Monte Carlo studies of the magnetic hysteresis and spin-dependent transport in thin films formed by ordered arrays of magnetic nanoparticles. Emphasis is given to the modifications of the single-particle behavior due to interparticle dipolar interactions as these arise in quantities of experimental interest, such as, the magnetization, the susceptibility and the magnetoresistance. We investigate the role of the structural parameters of an array (interparticle separation, number of stacked monolayers) and the role of the internal structure of the nanoparticles (single phase, core-shell). Dipolar interactions are responsible for anisotropic magnetic behavior between the in-plane and out-of-plane directions of the sample, which is reflected on the investigated magnetic properties (magnetization, transverse susceptibility and magnetoresistance) and the parameters of the array (remanent magnetization, coercive field, and blocking temperature). Our numerical results are compared to existing measurements on self-assembled arrays of Fe-based and Co nanoparticles is made.

  5. Energy- and momentum-resolved exchange and spin-orbit interaction in cobalt film by spin-polarized two-electron spectroscopy.

    PubMed

    Samarin, S; Artamonov, O M; Sergeant, A D; Stamps, R; Williams, J F

    2006-09-01

    Spontaneous ordering of electronic spins in ferromagnetic materials is one of the best known and most studied examples of quantum correlations. Exchange correlations are responsible for long range spin order and the spin-orbit interaction (SOI) can create preferred crystalline directions for the spins, i.e., magnetic anisotropy. Presented experimental data illustrate how novel spin-polarized two-electron spectroscopy in-reflection mode allows observation of the localization of spin-dependent interactions in energy-momentum space. Comparison of spin-orbit asymmetries in spectra of Co film and clean W(110) may indicate the presence of interface specific proximity effects providing important clues to the formation of preferred orientations for the magnetic moment of the Co film. These results may help to understand the microscopic origin of interface magnetic anisotropy.

  6. Spin transport in intermediate-energy heavy-ion collisions as a probe of in-medium spin-orbit interactions

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    The spin up-down splitting of collective flows in intermediate-energy heavy-ion collisions as a result of the nuclear spin-orbit interaction is investigated within a spin- and isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model SIBUU12. Using a Skyrme-type spin-orbit coupling quadratic in momentum, we found that the spin splittings of the directed flow and elliptic flow are largest in peripheral Au+Au collisions at beam energies of about 100-200 MeV/nucleon, and the effect is considerable even in smaller systems especially for nucleons with high transverse momenta. The collective flows of light clusters of different spin states are also investigated using an improved dynamical coalescence model with spin. Our study can be important in understanding the properties of in-medium nuclear spin-orbit interactions once the spin-dependent observables proposed in this work can be measured.

  7. Evidence that hMLH3 functions primarily in meiosis and in hMSH2-hMSH3 mismatch repair.

    PubMed

    Charbonneau, Nicole; Amunugama, Ravindra; Schmutte, Christoph; Yoder, Kristine; Fishel, Richard

    2009-07-01

    The MutS (MSH) and MutL (MLH) homologs are conserved proteins that function in mismatch repair (MMR) and meiosis. We examined mRNA and protein expression of hMLH3 compared to other human MSH and MLH in a panel of human tissues and the HeLa cell line. Quantitative PCR suggests that MSH and MLH transcripts are expressed ubiquitously. hMLH3 mRNA is present at low levels in numerous tissues. Protein expression appears to correlate with a threshold of mRNA expression with hMLH3 present at high levels in testis. In addition, we have found and mapped interactions between hMLH1 and hMLH3 with hMSH3. These data are consistent with yeast studies and suggest a role for hMLH3 in meiosis as well as hMSH2-hMSH3 repair processes and little if any role in Hereditary Non-Polyposis Colorectal Cancer (HNPCC).

  8. A simplified PBPK modeling approach for prediction of pharmacokinetics of four primarily renally excreted and CYP3A metabolized compounds during pregnancy.

    PubMed

    Xia, Binfeng; Heimbach, Tycho; Gollen, Rakesh; Nanavati, Charvi; He, Handan

    2013-10-01

    During pregnancy, a drug's pharmacokinetics may be altered and hence anticipation of potential systemic exposure changes is highly desirable. Physiologically based pharmacokinetics (PBPK) models have recently been used to influence clinical trial design or to facilitate regulatory interactions. Ideally, whole-body PBPK models can be used to predict a drug's systemic exposure in pregnant women based on major physiological changes which can impact drug clearance (i.e., in the kidney and liver) and distribution (i.e., adipose and fetoplacental unit). We described a simple and readily implementable multitissue/organ whole-body PBPK model with key pregnancy-related physiological parameters to characterize the PK of reference drugs (metformin, digoxin, midazolam, and emtricitabine) in pregnant women compared with the PK in nonpregnant or postpartum (PP) women. Physiological data related to changes in maternal body weight, tissue volume, cardiac output, renal function, blood flows, and cytochrome P450 activity were collected from the literature and incorporated into the structural PBPK model that describes HV or PP women PK data. Subsequently, the changes in exposure (area under the curve (AUC) and maximum concentration (C max)) in pregnant women were simulated. Model-simulated PK profiles were overall in agreement with observed data. The prediction fold error for C max and AUC ratio (pregnant vs. nonpregnant) was less than 1.3-fold, indicating that the pregnant PBPK model is useful. The utilization of this simplified model in drug development may aid in designing clinical studies to identify potential exposure changes in pregnant women a priori for compounds which are mainly eliminated renally or metabolized by CYP3A4.

  9. Impaired compensation to femoral artery ligation in diet-induced obese mice is primarily mediated via suppression of collateral growth by Nox2 and p47phox

    PubMed Central

    DiStasi, Matthew R.; Mund, Julie A.; Bohlen, H. Glenn; Miller, Steven J.; Ingram, David A.; Dalsing, Michael C.

    2015-01-01

    The present study was undertaken to establish the role of NADPH oxidase (Nox) in impaired vascular compensation to arterial occlusion that occurs in the presence of risk factors associated with oxidative stress. Diet-induced obese (DIO) mice characterized by multiple comorbidities including diabetes and hyperlipidemia were used as a preclinical model. Arterial occlusion was induced by distal femoral artery ligation in lean and DIO mice. Proximal collateral arteries were identified as the site of major (∼70%) vascular resistance to calf perfusion by distal arterial pressures, which decreased from ∼80 to ∼30 mmHg with ligation in both lean and DIO mice. Two weeks after ligation, significant vascular compensation occurred in lean but not DIO mice as evidenced by increased perfusion (147 ± 48% vs. 49 ± 29%) and collateral diameter (151 ± 30% vs. 44 ± 17%). Vascular mRNA expression of p22phox, Nox2, Nox4, and p47phox were all increased in DIO mice. Treatment of DIO mice with either apocynin or Nox2ds-tat or with whole body ablation of either Nox2 or p47phox ameliorated the impairment in both collateral growth and hindlimb perfusion. Multiparametric flow cytometry analysis demonstrated elevated levels of circulating monocytes in DIO mice without impaired mobilization and demargination after femoral artery ligation. These results establish collateral resistance as the major limitation to calf perfusion in this preclinical model, demonstrate than monocyte mobilization and demarginatin is not suppressed, implicate Nox2-p47phox interactions in the impairment of vascular compensation to arterial occlusion in DIO mice, and suggest that selective Nox component suppression/inhibition may be effective as either primary or adjuvant therapy for claudicants. PMID:26297224

  10. The Cellular TAR RNA Binding Protein, TRBP, Promotes HIV-1 Replication Primarily by Inhibiting the Activation of Double-Stranded RNA-Dependent Kinase PKR▿

    PubMed Central

    Sanghvi, Viraj R.; Steel, Laura F.

    2011-01-01

    The TAR RNA binding protein, TRBP, is a cellular double-stranded RNA (dsRNA) binding protein that can promote the replication of HIV-1 through interactions with the viral TAR element as well as with cellular proteins that affect the efficiency of translation of viral transcripts. The structured TAR element, present on all viral transcripts, can impede efficient translation either by sterically blocking access of translation initiation factors to the 5′-cap or by activating the dsRNA-dependent kinase, PKR. Several mechanisms by which TRBP can facilitate translation of viral transcripts have been proposed, including the binding and unwinding of TAR and the suppression of PKR activation. Further, TRBP has been identified as a cofactor of Dicer in the processing of microRNAs (miRNAs), and sequestration of TRBP by TAR in infected cells has been proposed as a viral countermeasure to potential host cell RNA interference-based antiviral activities. Here, we have addressed the relative importance of these various roles for TRBP in HIV-1 replication. Using Jurkat T cells, primary human CD4+ T cells, and additional cultured cell lines, we show that depletion of TRBP has no effect on viral replication when PKR activation is otherwise blocked. Moreover, the presence of TAR-containing mRNAs does not affect the efficacy of cellular miRNA silencing pathways. These results establish that TRBP, when expressed at physiological levels, promotes HIV-1 replication mainly by suppressing the PKR-mediated antiviral response, while its contribution to HIV-1 replication through PKR-independent pathways is minimal. PMID:21937648

  11. Superior Immunogenicity of Inactivated Whole Virus H5N1 Influenza Vaccine is Primarily Controlled by Toll-like Receptor Signalling

    PubMed Central

    Geeraedts, Felix; Goutagny, Nadege; Hornung, Veit; Severa, Martina; de Haan, Aalzen; Pool, Judith; Wilschut, Jan; Fitzgerald, Katherine A.; Huckriede, Anke

    2008-01-01

    In the case of an influenza pandemic, the current global influenza vaccine production capacity will be unable to meet the demand for billions of vaccine doses. The ongoing threat of an H5N1 pandemic therefore urges the development of highly immunogenic, dose-sparing vaccine formulations. In unprimed individuals, inactivated whole virus (WIV) vaccines are more immunogenic and induce protective antibody responses at a lower antigen dose than other formulations like split virus (SV) or subunit (SU) vaccines. The reason for this discrepancy in immunogenicity is a long-standing enigma. Here, we show that stimulation of Toll-like receptors (TLRs) of the innate immune system, in particular stimulation of TLR7, by H5N1 WIV vaccine is the prime determinant of the greater magnitude and Th1 polarization of the WIV-induced immune response, as compared to SV- or SU-induced responses. This TLR dependency largely explains the relative loss of immunogenicity in SV and SU vaccines. The natural pathogen-associated molecular pattern (PAMP) recognized by TLR7 is viral genomic ssRNA. Processing of whole virus particles into SV or SU vaccines destroys the integrity of the viral particle and leaves the viral RNA prone to degradation or involves its active removal. Our results show for a classic vaccine that the acquired immune response evoked by vaccination can be enhanced and steered by the innate immune system, which is triggered by interaction of an intrinsic vaccine component with a pattern recognition receptor (PRR). The insights presented here may be used to further improve the immune-stimulatory and dose-sparing properties of classic influenza vaccine formulations such as WIV, and will facilitate the development of new, even more powerful vaccines to face the next influenza pandemic. PMID:18769719

  12. Interactive Heat Transfer Simulations for Everyone

    ERIC Educational Resources Information Center

    Xie, Charles

    2012-01-01

    Heat transfer is widely taught in secondary Earth science and physics. Researchers have identified many misconceptions related to heat and temperature. These misconceptions primarily stem from hunches developed in everyday life (though the confusions in terminology often worsen them). Interactive computer simulations that visualize thermal energy,…

  13. Interactive Reading on the Secondary Level.

    ERIC Educational Resources Information Center

    Gross, Patricia A.

    A study of two teachers and four secondary level English classes examined how traditional methods of teaching literature were replaced by more interactive and integrated approaches to text, based primarily upon a whole language philosophy. Intervention aspects purposely remained open-ended to accommodate each teacher's understandings and…

  14. Platelet–neutrophil interactions under thromboinflammatory conditions

    PubMed Central

    Li, Jing; Kim, Kyungho; Barazia, Andrew; Tseng, Alan

    2015-01-01

    Platelets primarily mediate hemostasis and thrombosis, whereas leukocytes are responsible for immune responses. Since platelets interact with leukocytes at the site of vascular injury, thrombosis and vascular inflammation are closely intertwined and occur consecutively. Recent studies using real-time imaging technology demonstrated that platelet–neutrophil interactions on the activated endothelium are an important determinant of microvascular occlusion during thromboinflammatory disease in which inflammation is coupled to thrombosis. Although the major receptors and counter receptors have been identified, it remains poorly understood how heterotypic platelet–neutrophil interactions are regulated under disease conditions. This review discusses our current understanding of the regulatory mechanisms of platelet– neutrophil interactions in thromboinflammatory disease. PMID:25650236

  15. U(1) chiral symmetry in a one-dimensional interacting electron system with spin

    NASA Astrophysics Data System (ADS)

    Lee, Taejin

    2016-11-01

    We study a spin-dependent Tomonaga-Luttinger model in one dimension, which describes electron transport through a single barrier. Using the Fermi-Bose equivalence in one dimension, we map the model onto a massless Thirring model with a boundary interaction. A field theoretical perturbation theory for the model has been developed, and the chiral symmetry is found to play an important role. The classical bulk action possesses a global U A (1)4 chiral symmetry because the fermion fields are massless. This global chiral symmetry is broken by the boundary interaction, and the bosonic degrees of freedom, corresponding to a chiral phase transformation, become dynamical. They acquire an additional kinetic action from the fermion path-integral measure and govern the critical behaviors of the physical operators. On the critical line where the boundary interaction becomes marginal, they decouple from the fermi fields. Consequently, the action reduces to the free-field action, which contains only a fermion bilinear boundary mass term as an interaction term. By using a renormalization group analysis, we obtain a new critical line, which differs from the previously known critical lines in the literature. The result of this work implies that the phase diagram of the one-dimensional electron system may have a richer structure than previously thought.

  16. Interaction-Driven Topological Insulator in Fermionic Cold Atoms on an Optical Lattice: A Design with a Density Functional Formalism.

    PubMed

    Kitamura, Sota; Tsuji, Naoto; Aoki, Hideo

    2015-07-24

    We design an interaction-driven topological insulator for fermionic cold atoms in an optical lattice; that is, we pose the question of whether we can realize in a continuous space a spontaneous symmetry breaking induced by the interatom interaction into a topological Chern insulator. Such a state, sometimes called a "topological Mott insulator," has yet to be realized in solid-state systems, since this requires, in the tight-binding model, large off-site interactions on top of a small on-site interaction. Here, we overcome the difficulty by introducing a spin-dependent potential, where a spin-selective occupation of fermions in A and B sublattices makes the on-site interaction Pauli forbidden, while a sizeable intersite interaction is achieved by a shallow optical potential with a large overlap between neighboring Wannier orbitals. This puts the system away from the tight-binding model, so that we adopt density functional theory for cold atoms, here extended to accommodate noncollinear spin structures emerging in the topological regime, to quantitatively demonstrate the phase transition to the topological Mott insulator.

  17. Interactional Context and Feedback in Child ESL Classrooms.

    ERIC Educational Resources Information Center

    Oliver, Rhonda; Mackey, Alison

    2003-01-01

    Examines the role of interactional context in exchanges between teachers and learners in English-as-a-Second-Language classrooms. Teacher-learner exchanges were categorized as being primarily focused on content, communication, management, or explicit language. Suggests that the importance of the interactional context should not be underestimated…

  18. Precision test of charge independence of hadronic interactions

    SciTech Connect

    Artuso, M.

    1986-10-01

    Broken symmetries are among the richest sources of information about the fundamental interactions: the renewed interest in the study of isospin non-conservation by strong forces is closely related to the effort of understanding some properties of nuclear systems in terms of their basic degrees of freedom. The hope is to be able to relate the pattern of the dynamical breaking of this symmetry to the mass spectrum of light quarks: to this purpose a more detailed phenomenological knowledge must be provided by a new generation of experiments. These considerations motivated a precision test of charge independence of strong nuclear interactions through a measurement of the parameters ..delta..A/sub y//sub 0/(theta) = A/sub y//sub 0/(theta,/sup 3/H) - A/sub y//sub 0/(theta,/sup 3/He), (the difference in analyzing power), and R identical with dsigma(theta/sup 3/H)/dsigma(theta,/sup 3/He) for the two reactions: vector p + d ..-->.. /sup 3/H + ..pi../sup +/, vector p + d ..-->.. /sup 3/He + ..pi../sup 0/. The observable ..delta..A/sub y//sub 0/ is particularly relevant as it probes the spin dependent term of the symmetry breaking interaction, on which so far almost no empirical evidence is available. The experiment has been performed at the Los Alamos Meson Physics Facility, using the N-type polarized proton beam (T/sub vector p/ = 733 MeV), and detecting the charged heavy particle in the HRS magnetic spectrometer. The final results are: ..delta..A/sub y//sub 0/ = A/sub y//sub 0/(/sup 3/H) - A/sub y//sub 0/(/sup 3/He) = 0.3930 - 0.3996 = -0.0066 +- 0.0040 +- (0.0018) and R = 2.193 +- 0.007 +- (0.027), where the first errors are statistical and the second systematic. 107 refs., 23 tabs., 63 figs.

  19. Weakly interacting massive particle-nucleus elastic scattering response

    NASA Astrophysics Data System (ADS)

    Anand, Nikhil; Fitzpatrick, A. Liam; Haxton, W. C.

    2014-06-01

    Background: A model-independent formulation of weakly interacting massive particle (WIMP)-nucleon scattering was recently developed in Galilean-invariant effective field theory. Purpose: Here we complete the embedding of this effective interaction in the nucleus, constructing the most general elastic nuclear cross section as a factorized product of WIMP and nuclear response functions. This form explicitly defines what can and cannot be learned about the low-energy constants of the effective theory—and consequently about candidate ultraviolet theories of dark matter—from elastic scattering experiments. Results: We identify those interactions that cannot be reliably treated in a spin-independent/spin-dependent (SI/SD) formulation: For derivative- or velocity-dependent couplings, the SI/SD formulation generally mischaracterizes the relevant nuclear operator and its multipolarity (e.g., scalar or vector) and greatly underestimates experimental sensitivities. This can lead to apparent conflicts between experiments when, in fact, none may exist. The new nuclear responses appearing in the factorized cross section are related to familiar electroweak nuclear operators such as angular momentum l⃗(i) and the spin-orbit coupling σ⃗(i).l⃗(i). Conclusions: To unambiguously interpret experiments and to extract all of the available information on the particle physics of dark matter, experimentalists will need to (1) do a sufficient number of experiments with nuclear targets having the requisite sensitivities to the various operators and (2) analyze the results in a formalism that does not arbitrarily limit the candidate operators. In an appendix we describe a code that is available to help interested readers implement such an analysis.

  20. Interacting faults

    NASA Astrophysics Data System (ADS)

    Peacock, D. C. P.; Nixon, C. W.; Rotevatn, A.; Sanderson, D. J.; Zuluaga, L. F.

    2017-04-01

    The way that faults interact with each other controls fault geometries, displacements and strains. Faults rarely occur individually but as sets or networks, with the arrangement of these faults producing a variety of different fault interactions. Fault interactions are characterised in terms of the following: 1) Geometry - the spatial arrangement of the faults. Interacting faults may or may not be geometrically linked (i.e. physically connected), when fault planes share an intersection line. 2) Kinematics - the displacement distributions of the interacting faults and whether the displacement directions are parallel, perpendicular or oblique to the intersection line. Interacting faults may or may not be kinematically linked, where the displacements, stresses and strains of one fault influences those of the other. 3) Displacement and strain in the interaction zone - whether the faults have the same or opposite displacement directions, and if extension or contraction dominates in the acute bisector between the faults. 4) Chronology - the relative ages of the faults. This characterisation scheme is used to suggest a classification for interacting faults. Different types of interaction are illustrated using metre-scale faults from the Mesozoic rocks of Somerset and examples from the literature.

  1. Imagined Interactions

    ERIC Educational Resources Information Center

    Honeycutt, James M.

    2010-01-01

    Social scientists have been studying imagined interactions since the mid-1980s and have measured numerous physiological correlates (Honeycutt, 2010). In this commentary I assess the research reported in Crisp and Turner (May-June 2009) and highlight the underlying mechanisms of imagined interactions that have empirically been laid out across…

  2. Tailoring MoS2 Exciton-Plasmon Interaction by Optical Spin-Orbit Coupling.

    PubMed

    Li, Ziwei; Li, Yu; Han, Tianyang; Wang, Xingli; Yu, Ying; Tay, Bengkang; Liu, Zheng; Fang, Zheyu

    2017-02-28

    Molybdenum disulfide (MoS2) monolayer as one of the atomic thickness two-dimensional materials has remarkable electronic and optical properties, which is an ideal candidate for a wide range of optoelectronic applications. However, the atomic monolayer thickness poses a significant challenge in MoS2 photoluminescence emission due to weak light-matter interaction. Here, we investigate the MoS2 exciton-plasmon interaction with spin-orbit coupling of light. The plasmonic spiral rings with subwavelength dimensions are designed and fabricated on hybrid substrates. MoS2 photoluminescence enhancement can be actively controlled by changing the incident optical spin states, laser powers, and the nanospiral geometries, which is arising from the change of field enhancement at near-field region. Planar light-emitting devices based on spin-orbit coupling (SOC) effect were further realized and flexibly controlled by changing the polarization of light. The SOC effect is discussed by the accumulation of geometric and dynamic phases, which can be demonstrated and elaborated by the Majorana sphere model. Our results provide a way to manipulate MoS2 light-matter interaction actively and can be further applied in the spin-dependent light-emitting devices at the nanoscale.

  3. Engineering 2D Ising Interactions in a Large (N>100) Ensemble of Trapped Ions

    NASA Astrophysics Data System (ADS)

    Sawyer, Brian; Britton, Joseph; Keith, Adam; Wang, Joseph; Freericks, James; Uys, Hermann; Biercuk, Michael; Bollinger, John

    2012-06-01

    Experimental progress in atomic, molecular, and optical physics has enabled exquisite control over ensembles of cold trapped ions. We have recently engineered long-range Ising interactions in a two-dimensional, 1-mK Coulomb crystal of hundreds of ^9Be^+ ions confined within a Penning trap. Interactions between the ^9Be^+ valence spins are mediated via spin-dependent optical dipole forces (ODFs) coupling to transverse motional modes of the planar crystal. A continuous range of inverse power-law spin-spin interactions from infinite (1/r^0) to dipolar (1/r^3) are accessible by varying the ODF drive frequency relative to the transverse modes. The ions naturally form a triangular lattice structure within the planar array, allowing for simulation of spin frustration using our generated antiferromagnetic couplings. We report progress toward simulating the ferromagnetic/antiferromagnetic transverse quantum Ising Hamiltonians in this large ensemble. We also report spectroscopy, thermometry, and sensitive displacement detection (˜100 pm) via entanglement of valence spin and drumhead oscillations.

  4. Strong interface-induced spin-orbit interaction in graphene on WS2.

    PubMed

    Wang, Zhe; Ki, Dong-Keun; Chen, Hua; Berger, Helmuth; MacDonald, Allan H; Morpurgo, Alberto F

    2015-09-22

    Interfacial interactions allow the electronic properties of graphene to be modified, as recently demonstrated by the appearance of satellite Dirac cones in graphene on hexagonal boron nitride substrates. Ongoing research strives to explore interfacial interactions with other materials to engineer targeted electronic properties. Here we show that with a tungsten disulfide (WS2) substrate, the strength of the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The induced SOI leads to a pronounced low-temperature weak anti-localization effect and to a spin-relaxation time two to three orders of magnitude smaller than in graphene on conventional substrates. To interpret our findings we have performed first-principle electronic structure calculations, which confirm that carriers in graphene on WS2 experience a strong SOI and allow us to extract a spin-dependent low-energy effective Hamiltonian. Our analysis shows that the use of WS2 substrates opens a possible new route to access topological states of matter in graphene-based systems.

  5. Fidelity decay and entropy production in many-particle systems after random interaction quench

    NASA Astrophysics Data System (ADS)

    Haldar, Sudip Kumar; Chavda, N. D.; Vyas, Manan; Kota, V. K. B.

    2016-04-01

    We analyze the effect of spin degree of freedom on fidelity decay and entropy production of a many-particle fermionic (bosonic) system in a mean-field, quenched by a random two-body interaction preserving many-particle spin S. The system Hamiltonian is represented by embedded Gaussian orthogonal ensemble (EGOE) of random matrices (for time-reversal and rotationally invariant systems) with one plus two-body interactions preserving S for fermions/bosons. EGOE are paradigmatic models to study the dynamical transition from integrability to chaos in interacting many-body quantum systems. A simple general picture, in which the variances of the eigenvalue density play a central role, is obtained for describing the short-time dynamics of fidelity decay and entropy production. Using some approximations, an EGOE formula for the time (t sat) for the onset of saturation of entropy, is also derived. These analytical EGOE results are in good agreement with numerical calculations. Moreover, both fermion and boson systems show significant spin dependence on the relaxation dynamics of the fidelity and entropy.

  6. Primarily isolated hepatic involvement of amyloidosis

    PubMed Central

    Ye, Lei; Shi, Hui; Wu, Hui-Min; Wang, Fang-Yu

    2016-01-01

    Abstract Background: Amyloidosis is particularly difficult to diagnose because the signs and symptoms are subtle. Additionally, there are no specific imaging or laboratory tests, except histopathology. Although it is considered to be a systemic disorder, a small portion of cases may be localized. Introduction of the case: A 54-year-old man presented with nonspecific symptoms (jaundice and back pruritus). Biochemical tests showed a high level of bilirubin and elevated serum tumor markers (CA19–9 and CA125). Routine imaging showed hepatomegaly without heterogeneous enhancement. Liver biopsy confirmed the diagnosis of hepatic amyloidosis. No cardiac or renal involvement was found. The patient accepted treatment involving oral chemotherapy. Conclusion: A rare and unique presentation of hepatic amyloidosis was highlighted in this case. PMID:28033255

  7. It's All Good: Children's Personality Attributions after Repeated Success and Failure in Peer and Computer Interactions

    ERIC Educational Resources Information Center

    Boseovski, Janet J.; Shallwani, Sadaf; Lee, Kang

    2009-01-01

    The present study examined children's use of behavioural outcome information to make personality attributions in social and non-social contexts. One hundred and twenty-eight 3- to 6-year-olds were told about a story actor who engaged in primarily successful or primarily unsuccessful interactions with several different people (social context) or…

  8. Interacting parasites

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2010-01-01

    Parasitism is the most popular life-style on Earth, and many vertebrates host more than one kind of parasite at a time. A common assumption is that parasite species rarely interact, because they often exploit different tissues in a host, and this use of discrete resources limits competition (1). On page 243 of this issue, however, Telfer et al. (2) provide a convincing case of a highly interactive parasite community in voles, and show how infection with one parasite can affect susceptibility to others. If some human parasites are equally interactive, our current, disease-by-disease approach to modeling and treating infectious diseases is inadequate (3).

  9. Interactive Video, Tablets and Self-Paced Learning in the Classroom: Preservice Teachers Perceptions

    ERIC Educational Resources Information Center

    Papadopoulou, Anthia; Palaigeorgiou, George

    2016-01-01

    In recent years, a lot of focus has been given to the study of interactive video. However, interactive video has not been examined as a tool for self-directed learning in the classroom and has not been exploited together with tablets. This study tries to assess the value of an e-learning environment which is based primarily on interactive learning…

  10. The Student-Faculty Relationship: An Investigation of the Interactions between Students and Faculty

    ERIC Educational Resources Information Center

    Ross, Justin Meredith

    2013-01-01

    The purpose of this study was to explore the subjective perceptions held by students of their interactions with faculty members in college, especially as those interactions relate to the integration and membership of students in the academic community. Academic integration, resulting primarily from student-faculty interactions, has been theorized…

  11. Constraints on low-mass WIMP interactions on 19F from PICASSO

    NASA Astrophysics Data System (ADS)

    Archambault, S.; Behnke, E.; Bhattacharjee, P.; Bhattacharya, S.; Dai, X.; Das, M.; Davour, A.; Debris, F.; Dhungana, N.; Farine, J.; Gagnebin, S.; Giroux, G.; Grace, E.; Jackson, C. M.; Kamaha, A.; Krauss, C.; Kumaratunga, S.; Lafrenière, M.; Laurin, M.; Lawson, I.; Lessard, L.; Levine, I.; Levy, C.; MacDonald, R. P.; Marlisov, D.; Martin, J.-P.; Mitra, P.; Noble, A. J.; Piro, M.-C.; Podviyanuk, R.; Pospisil, S.; Saha, S.; Scallon, O.; Seth, S.; Starinski, N.; Stekl, I.; Wichoski, U.; Xie, T.; Zacek, V.

    2012-05-01

    Recent results from the PICASSO dark matter search experiment at SNOLAB are reported. These results were obtained using a subset of 10 detectors with a total target mass of 0.72 kg of 19F and an exposure of 114 kgd. The low backgrounds in PICASSO allow recoil energy thresholds as low as 1.7 keV to be obtained which results in an increased sensitivity to interactions from Weakly Interacting Massive Particles (WIMPs) with masses below 10 GeV/c2. No dark matter signal was found. Best exclusion limits in the spin dependent sector were obtained for WIMP masses of 20 GeV/c2 with a cross section on protons of σpSD=0.032 pb (90% C.L.). In the spin independent sector close to the low mass region of 7 GeV/c2 favoured by CoGeNT and DAMA/LIBRA, cross sections larger than σpSI=1.41×10-4 pb (90% C.L.) are excluded.

  12. Effect of the intrinsic spin-orbit interaction on the tunnel magnetoresistance in graphenelike nanoflakes

    NASA Astrophysics Data System (ADS)

    Weymann, Ireneusz; Krompiewski, Stefan

    2016-12-01

    This paper is devoted to examining the effect of intrinsic spin-orbit interaction on the possible appearance of edge magnetic moments and spin-dependent transport in graphenelike nanoflakes. In the case of finite-size graphenelike nanostructures it is shown that, on one hand, energetically the most advantageous configuration corresponds to magnetic moments located at zigzag edges with the in-plane antiferromagnetic inter-edge coupling. On the other hand, the tunnel magnetoresistance and the shot noise also have thoroughly been tested both for the in-plane configuration as well as for the out-of-plane one (for comparison reasons). Transport properties are described in terms of the mean-field Kane-Mele-Hubbard model with spin mixing correlations, supplemented by additional terms describing external leads, charging energy, and lead-nanostructure tunneling. The results show that Coulomb blockade stability spectra of graphenelike nanoflakes with ferromagnetic contacts provide information on both the intrinsic spin-orbit interaction and the expected edge magnetism.

  13. Strong Interaction

    SciTech Connect

    Karsch, F.; Vogelsang, V.

    2009-09-29

    We will give here an overview of our theory of the strong interactions, Quantum Chromo Dynamics (QCD) and its properties. We will also briefly review the history of the study of the strong interactions, and the discoveries that ultimately led to the formulation of QCD. The strong force is one of the four known fundamental forces in nature, the others being the electromagnetic, the weak and the gravitational force. The strong force, usually referred to by scientists as the 'strong interaction', is relevant at the subatomic level, where it is responsible for the binding of protons and neutrons to atomic nuclei. To do this, it must overcome the electric repulsion between the protons in an atomic nucleus and be the most powerful force over distances of a few fm (1fm=1 femtometer=1 fermi=10{sup -15}m), the typical size of a nucleus. This property gave the strong force its name.

  14. High Statistics Analysis using Anisotropic Clover Lattices: (III) Baryon-Baryon Interactions

    SciTech Connect

    Silas Beane; Detmold, William; Lin, Huey-Wen; Luu, Thomas C.; Orginos, Kostas; Savage, Martin; Torok, Aaron M.; Walker-Loud, Andre

    2010-03-01

    Low-energy baryon-baryon interactions are calculated in a high-statistics lattice QCD study on a single ensemble of anisotropic clover gauge-field configurations at a pion mass of m_pi ~ 390 MeV, a spatial volume of L^3 ~ (2.5 fm)^3, and a spatial lattice spacing of b ~ 0.123 fm. Luscher’s method is used to extract nucleon-nucleon, hyperon-nucleon and hyperon-hyperon scattering phase shifts at one momentum from the one- and two-baryon ground-state energies in the lattice volume. The N-Sigma interactions are found to be highly spin-dependent, and the interaction in the ^3 S _1 channel is found to be strong. In contrast, the N-Lambda interactions are found to be spin-independent, within the uncertainties of the calculation, consistent with the absence of one-pion-exchange. The only channel for which a negative energy-shift is found is Lambda-Lambda, indicating that the Lambda-Lambda interaction is attractive, as anticipated from model-dependent discussions regarding the H-dibaryon. The NN scattering lengths are found to be small, clearly indicating the absence of any fine-tuning in the NN-sector at this pion mass. This is consistent with our previous Lattice QCD calculation of the NN interactions. The behavior of the signal-to-noise ratio in the baryon-baryon correlation functions, and in the ratio of correlation functions that yields the ground-state energy splitting

  15. High statistics analysis using anisotropic clover lattices: (III) Baryon-baryon interactions

    SciTech Connect

    Beane, S; Detmold, W; Lin, H; Luu, T; Orginos, K; Savage, M; Torok, A; Walker-Loud, A

    2010-01-19

    Low-energy baryon-baryon interactions are calculated in a high-statistics lattice QCD study on a single ensemble of anisotropic clover gauge-field configurations at a pion mass of m{sub {pi}} {approx} 390 MeV, a spatial volume of L{sup 3} {approx} (2.5 fm){sup 3}, and a spatial lattice spacing of b {approx} 0.123 fm. Luescher's method is used to extract nucleon-nucleon, hyperon-nucleon and hyperon-hyperon scattering phase shifts at one momentum from the one- and two-baryon ground-state energies in the lattice volume. The isospin-3/2 N{Sigma} interactions are found to be highly spin-dependent, and the interaction in the {sup 3}S{sub 1} channel is found to be strong. In contrast, the N{Lambda} interactions are found to be spin-independent, within the uncertainties of the calculation, consistent with the absence of one-pion-exchange. The only channel for which a negative energy-shift is found is {Lambda}{Lambda}, indicating that the {Lambda}{Lambda} interaction is attractive, as anticipated from model-dependent discussions regarding the H-dibaryon. The NN scattering lengths are found to be small, clearly indicating the absence of any fine-tuning in the NN-sector at this pion mass. This is consistent with our previous Lattice QCD calculation of NN interactions. The behavior of the signal-to-noise ratio in the baryon-baryon correlation functions, and in the ratio of correlation functions that yields the ground-state energy splitting is explored. In particular, focus is placed on the window of time slices for which the signal-to-noise ratio does not degrade exponentially, as this provides the opportunity to extract quantitative information about multi-baryon systems.

  16. Weak Interactions

    DOE R&D Accomplishments Database

    Lee, T. D.

    1957-06-01

    Experimental results on the non-conservation of parity and charge conservation in weak interactions are reviewed. The two-component theory of the neutrino is discussed. Lepton reactions are examined under the assumption of the law of conservation of leptons and that the neutrino is described by a two- component theory. From the results of this examination, the universal Fermi interactions are analyzed. Although reactions involving the neutrino can be described, the same is not true of reactions which do not involve the lepton, as the discussion of the decay of K mesons and hyperons shows. The question of the invariance of time reversal is next examined. (J.S.R.)

  17. Interactive Astronomy.

    ERIC Educational Resources Information Center

    Martin, Jean K.

    1997-01-01

    Presents guiding principles for developing interactive lessons for the World Wide Web. Describes "Amazing Space: Education Online from the Hubble Space Telescope", a program where students study spectacular Hubble Space Telescope images of stars and star-forming regions to learn about the life cycle of stars and the creation of atoms. (JRH)

  18. Interacting Compasses

    ERIC Educational Resources Information Center

    Riveros, Hector G.; Betancourt, Julian

    2009-01-01

    The use of multiple compasses to map and visualize magnetic fields is well-known. The magnetic field exerts a torque on the compasses aligning them along the lines of force. Some science museums show the field of a magnet using a table with many compasses in a closely packed arrangement. However, the very interesting interactions that occur…

  19. [Pharmacokinetic interactions].

    PubMed

    Arazo Garcés, Piedad; de los Santos Gil, Ignacio

    2013-06-01

    Rilpivirine (RPV) is a nonnucleoside reverse transcriptase inhibitor (NNRTI) that has been approved for use in treatment-naïve patients and which has potent antiviral activity. Its adverse effects profile differs from that of first-generation NNRTs. The pharmacological interactions produced by RPV are due to its effects on the CYP450 system; RPV is a substrate and mild inducer of CYP3A4. Moreover, in vitro, RPV inhibits glycoprotein-P. RPV has clinically significant pharmacological interactions, especially with protease inhibitors (except boosted darunavir and lopinavir) and the NNRTIs efavirenz and nevirapine. Coadministration of RPV with drugs that increase gastric pH, such as omeprazole, or those inducing CYP3A4, such as rifampicin, can significantly reduce RPV concentrations and is contraindicated. The concomitant use of RPV with a CYP3A4 inhibitor (such as clarithromycin) can increase RPV concentrations. Administration of PRV with food is recommended to obtain better absorption and adequate plasma values.

  20. Disorder, three body interaction and Bose glass phase in a spinor atomic gas in an optical lattice

    NASA Astrophysics Data System (ADS)

    Nabi, Sk Noor; Basu, Saurabh

    2016-10-01

    We study the effects of disorder on the spin dependent interaction term of a spinor Bose Hubbard model with a three body interaction potential. The signature of the Bose glass (BG) phase is observed by computing the fraction of the lattice sites having finite superfluid (SF) order parameter and non integer occupation densities. We obtain the phase diagram both for the antiferromagnetic (AF) and ferromagnetic (F) cases via a percolation analysis. In the AF case, the BG phase intervenes between the odd-even Mott insulating (MI) lobes (for example, the lobes corresponding to occupation densities, n=1 and (n=2) but not between the even-odd MI lobes. In the ferromagnetic case, the presence of the BG phase is observed between all the MI lobes irrespective of them being even or odd. The BG phase almost destroys the first MI lobe while the MI phase looks more stable than the SF phase both in the AF and F cases due to the presence of the three body interactions.

  1. Self-assembled monolayers based spintronics: from ferromagnetic surface functionalization to spin-dependent transport

    NASA Astrophysics Data System (ADS)

    Tatay, Sergio; Galbiati, Marta; Delprat, Sophie; Barraud, Clément; Bouzehouane, Karim; Collin, Sophie; Deranlot, Cyrile; Jacquet, Eric; Seneor, Pierre; Mattana, Richard; Petroff, Frédéric

    2016-03-01

    Chemically functionalized surfaces are studied for a wide range of applications going from medicine to electronics. Whereas non-magnetic surfaces have been widely studied, functionalization of magnetic surfaces is much less common and has almost never been used for spintronics applications. In this article we present the functionalization of La2/3Sr1/3MnO3, a ferromagnetic oxide, with self-assembled monolayers for spintronics. La2/3Sr1/3MnO3 is the prototypical half-metallic manganite used in spintronics studies. First, we show that La2/3Sr1/3MnO3 can be functionalized by alkylphosphonic acid molecules. We then emphasize the use of these functionalized surfaces in spintronics devices such as magnetic tunnel junctions fabricated using a nano-indentation based lithography technique. The observed exponential increase of tunnel resistance as a function of alkyl chain length is a direct proof of the successful connection of molecules to ferromagnetic electrodes. For all alkyl chains studied we obtain stable and robust tunnel magnetoresistance, with effects ranging from a few tens to 10 000%. These results show that functionalized electrodes can be integrated in spintronics devices and open the door to a molecular engineering of spintronics.

  2. Thermally induced spin-dependent current based on Zigzag Germanene Nanoribbons

    NASA Astrophysics Data System (ADS)

    Majidi, Danial; Faez, Rahim

    2017-02-01

    In this paper, using first principle calculation and non-equilibrium Green's function, the thermally induced spin current in Hydrogen terminated Zigzag-edge Germanene Nanoribbon (ZGeNR-H) is investigated. In this model, because of the difference between the source and the drain temperature of ZGeNR device, the spin up and spin down currents flow in the opposite direction with two different threshold temperatures (Tth). Hence, a pure spin polarized current which belongs to spin down is obtained. It is shown that, for temperatures above the threshold temperature spin down current increases with the increasing temperature up to 75 K and then decreases. But spin up current rises steadily and in the high temperature we can obtain polarized spin up current. In addition, we show an acceptable spin current around the room temperature for ZGeNR. The transmission peaks in ZGeNR which are closer to the Fermi level rather than Zigzag Graphene Nanoribbon (ZGNRS) which causes ZGeNR to have spin current at higher temperatures. Finally, it is indicated that by tuning the back gate voltage, the spin current can be completely modulated and polarized. Simulation results verify the Zigzag Germanene Nanoribbon as a promising candidate for spin caloritronics devices, which can be applied in future low power consumption technology.

  3. Spin-dependent thermoelectric effects in Fe-C6 doped monolayer MoS2.

    PubMed

    Zhu, Lin; Zou, Fei; Gao, Guoying; Yao, Kailun

    2017-03-29

    By using the non-equilibrium Green's function with density functional theory, we have studied the thermal spin transport properties of Fe-C6 cluster doped monolayer MoS2. The results show that the device has a perfect Seebeck effect under temperature difference without gate voltage or bias voltage. Moreover, we also find the thermal colossal magnetoresistance effect, which is as high as 10(7)%. The competition between spin up electrons and spin down holes of the parallel spin configuration leads to peculiar behavior of colossal magnetoresistance and thermo-current, which is essential for the design of thermal transistors. These results are useful in future MoS2-based multifunctional spin caloritronic devices.

  4. Spin-Dependent Transport in Fe/GaAs(100)/Fe Vertical Spin-Valves

    PubMed Central

    Wong, P. K. Johnny; Zhang, Wen; Wu, Jing; Will, Iain G.; Xu, Yongbing; Xia, Ke; Holmes, Stuart N.; Farrer, Ian; Beere, Harvey E.; Ritchie, Dave A.

    2016-01-01

    The integration of magnetic materials with semiconductors will lead to the development of the next spintronics devices such as spin field effect transistor (SFET), which is capable of both data storage and processing. While the fabrication and transport studies of lateral SFET have attracted greatly attentions, there are only few studies of vertical devices, which may offer the opportunity for the future three-dimensional integration. Here, we provide evidence of two-terminal electrical spin injection and detection in Fe/GaAs/Fe vertical spin-valves (SVs) with the GaAs layer of 50 nanometers thick and top and bottom Fe electrodes deposited by molecular beam epitaxy. The spin-valve effect, which corresponds to the individual switching of the top and bottom Fe layers, is bias dependent and observed up to 20 K. We propose that the strongly bias- and temperature-dependent MR is associated with spin transport at the interfacial Fe/GaAs Schottky contacts and in the GaAs membranes, where balance between the barrier profiles as well as the dwell time to spin lifetime ratio are crucial factors for determining the device operations. The demonstration of the fabrication and spin injection in the vertical SV with a semiconductor interlayer is expected to open a new avenue in exploring the SFET. PMID:27432047

  5. Spin-dependent Otto quantum heat engine based on a molecular substance

    NASA Astrophysics Data System (ADS)

    Hübner, W.; Lefkidis, G.; Dong, C. D.; Chaudhuri, D.; Chotorlishvili, L.; Berakdar, J.

    2014-07-01

    We explore the potential of single molecules for thermodynamic cycles. To this end we propose two molecular heat engines based on the Ni2 dimer in the presence of a static magnetic field: (a) a quantum Otto engine and (b) a modified quantum Otto engine for which optical excitations induced by a laser pulse substitute for one of the heat-exchange points. For reliable predictions and to inspect the role of spin and electronic correlations we perform fully correlated ab initio calculations of the molecular electronic structure including spin-orbital effects. We analyze the efficiency of the engines in dependence of the electronic level scheme and the entanglement and find a significant possible enhancement connected to the quantum nature and the heat capacity of the dimer, as well as to the zero-field triplet states splitting.

  6. Spin-dependent Otto quantum heat engine based on a molecular substance

    NASA Astrophysics Data System (ADS)

    Hübner, Wolfgang; Lefkidis, Georgios; Dong, Chuanding; Chaudhuri, Debapriya; Chotorlishvili, Levan; Berakdar, Jamal

    2015-03-01

    We explore the potential of single molecules for thermodynamic cycles. To this end we propose two molecular heat engines based on the realistic Ni2 dimer: a quantum Otto engine and a modified quantum Otto engine for which laser-induced optical excitations substitute for one of the heat-exchange points. For reliable predictions and to inspect the role of spin and electronic correlations we perform fully correlated ab initio calculations of the electronic structure and the excited states. We analyze the efficiency and the word output of the derived engines and find an enhancement when the spin degree of freedom is included. We also use the von Neumann entropy to describe correlations and entanglement of the engines during the cycles. Furthermore, we link our results to previous results regarding an isobaric stroke and a magnetic quantum Diesel engine on the same substance.

  7. Ferromagnetic Control of Spin-Dependent Electron Currents in a Semiconductor

    NASA Astrophysics Data System (ADS)

    Sham, L. J.

    2005-03-01

    It is well known that electrons or neutrons scattered against a polarized target become polarized. This talk will show how this principle can be used in variety of ways to generate and to change a spin polarization in a current flowing in a semiconductor interfaced with one or more ferromagnets. In theory it is possible to generate a 100% polarized current or a pure spin current without charge current. The relative merits of the various configurations will be assessed. Experiment tests will be described. Possible device applications provide illustrations of the theory.Work done in collaboration with J.P. McGuire, C. Ciuti, Eric Yang, Yuchang Chen, Thomas Grange, and Ed Yu, and supported by NSF DMR 0099572, DARPA/ONR N0014-99-1-1096 and University of California Campus- Laboratories Cooperation project.

  8. Iterative Monte Carlo analysis of spin-dependent parton distributions

    DOE PAGES

    Sato, Nobuo; Melnitchouk, Wally; Kuhn, Sebastian E.; ...

    2016-04-05

    We present a comprehensive new global QCD analysis of polarized inclusive deep-inelastic scattering, including the latest high-precision data on longitudinal and transverse polarization asymmetries from Jefferson Lab and elsewhere. The analysis is performed using a new iterative Monte Carlo fitting technique which generates stable fits to polarized parton distribution functions (PDFs) with statistically rigorous uncertainties. Inclusion of the Jefferson Lab data leads to a reduction in the PDF errors for the valence and sea quarks, as well as in the gluon polarization uncertainty at x ≳ 0.1. Furthermore, the study also provides the first determination of the flavor-separated twist-3 PDFsmore » and the d2 moment of the nucleon within a global PDF analysis.« less

  9. Iterative Monte Carlo analysis of spin-dependent parton distributions

    SciTech Connect

    Sato, Nobuo; Melnitchouk, Wally; Kuhn, Sebastian E.; Ethier, Jacob J.; Accardi, Alberto

    2016-04-05

    We present a comprehensive new global QCD analysis of polarized inclusive deep-inelastic scattering, including the latest high-precision data on longitudinal and transverse polarization asymmetries from Jefferson Lab and elsewhere. The analysis is performed using a new iterative Monte Carlo fitting technique which generates stable fits to polarized parton distribution functions (PDFs) with statistically rigorous uncertainties. Inclusion of the Jefferson Lab data leads to a reduction in the PDF errors for the valence and sea quarks, as well as in the gluon polarization uncertainty at x ≳ 0.1. Furthermore, the study also provides the first determination of the flavor-separated twist-3 PDFs and the d2 moment of the nucleon within a global PDF analysis.

  10. Self-assembled monolayers based spintronics: from ferromagnetic surface functionalization to spin-dependent transport.

    PubMed

    Tatay, Sergio; Galbiati, Marta; Delprat, Sophie; Barraud, Clément; Bouzehouane, Karim; Collin, Sophie; Deranlot, Cyrile; Jacquet, Eric; Seneor, Pierre; Mattana, Richard; Petroff, Frédéric

    2016-03-09

    Chemically functionalized surfaces are studied for a wide range of applications going from medicine to electronics. Whereas non-magnetic surfaces have been widely studied, functionalization of magnetic surfaces is much less common and has almost never been used for spintronics applications. In this article we present the functionalization of La2/3Sr1/3MnO3, a ferromagnetic oxide, with self-assembled monolayers for spintronics. La2/3Sr1/3MnO3 is the prototypical half-metallic manganite used in spintronics studies. First, we show that La2/3Sr1/3MnO3 can be functionalized by alkylphosphonic acid molecules. We then emphasize the use of these functionalized surfaces in spintronics devices such as magnetic tunnel junctions fabricated using a nano-indentation based lithography technique. The observed exponential increase of tunnel resistance as a function of alkyl chain length is a direct proof of the successful connection of molecules to ferromagnetic electrodes. For all alkyl chains studied we obtain stable and robust tunnel magnetoresistance, with effects ranging from a few tens to 10 000%. These results show that functionalized electrodes can be integrated in spintronics devices and open the door to a molecular engineering of spintronics.

  11. Spin-Dependent Transport in Fe/GaAs(100)/Fe Vertical Spin-Valves

    NASA Astrophysics Data System (ADS)

    Wong, P. K. Johnny; Zhang, Wen; Wu, Jing; Will, Iain G.; Xu, Yongbing; Xia, Ke; Holmes, Stuart N.; Farrer, Ian; Beere, Harvey E.; Ritchie, Dave A.

    2016-07-01

    The integration of magnetic materials with semiconductors will lead to the development of the next spintronics devices such as spin field effect transistor (SFET), which is capable of both data storage and processing. While the fabrication and transport studies of lateral SFET have attracted greatly attentions, there are only few studies of vertical devices, which may offer the opportunity for the future three-dimensional integration. Here, we provide evidence of two-terminal electrical spin injection and detection in Fe/GaAs/Fe vertical spin-valves (SVs) with the GaAs layer of 50 nanometers thick and top and bottom Fe electrodes deposited by molecular beam epitaxy. The spin-valve effect, which corresponds to the individual switching of the top and bottom Fe layers, is bias dependent and observed up to 20 K. We propose that the strongly bias- and temperature-dependent MR is associated with spin transport at the interfacial Fe/GaAs Schottky contacts and in the GaAs membranes, where balance between the barrier profiles as well as the dwell time to spin lifetime ratio are crucial factors for determining the device operations. The demonstration of the fabrication and spin injection in the vertical SV with a semiconductor interlayer is expected to open a new avenue in exploring the SFET.

  12. Spin-dependent screening and Auger neutralization of He{sup +} ions in metals

    SciTech Connect

    Alducin, M.; Diez Muino, R.; Juaristi, J.I.

    2004-07-01

    The screening of a He{sup +} ion embedded in a paramagnetic electron gas is studied using density functional theory within the local spin density approximation. We calculate the induced electron density and the induced density of states for each spin orientation, parallel and antiparallel to that of the electron bound to the He{sup +} ion. Our results show that the screening is preferably due to parallel spin electrons, especially for low electron densities of the medium. In a second step, the rates for Auger neutralization of a He{sup +} ion in an electron gas are calculated, paying special attention to their dependence on the spin of the electron excited in the Auger process. The results obtained are used to interpret experiments in which the spin polarization of the emitted yield is measured when a He{sup +} projectile is neutralized in front of a metal surface.

  13. Prediction of spin-dependent electronic structure in 3d-transition-metal doped antimonene

    NASA Astrophysics Data System (ADS)

    Yang, L. F.; Song, Y.; Mi, W. B.; Wang, X. C.

    2016-07-01

    We investigate the geometric structure and electronic and magnetic properties of 3d-transition-metal atom doped antimonene using spin-polarized first-principles calculations. Strong orbital hybridization exhibits between 3d-transition-metal and Sb atoms, where covalent bonds form in antimonene. A spin-polarized semiconducting state appears in Cr-doped antimonene, while half-metallic states appear by doping Ti, V, and Mn. These findings indicate that once combined with doping states, the bands of antimonene systems offer a variety of features. Specific dopants lead to half-metallic characters with high spin polarization that has potential application in spintronics.

  14. Wide-field multispectral super-resolution imaging using spin-dependent fluorescence in nanodiamonds.

    PubMed

    Chen, Edward H; Gaathon, Ophir; Trusheim, Matthew E; Englund, Dirk

    2013-05-08

    Recent advances in fluorescence microscopy have enabled spatial resolution below the diffraction limit by localizing multiple temporally or spectrally distinguishable fluorophores. Here, we introduce a super-resolution technique that deterministically controls the brightness of uniquely addressable, photostable emitters. We modulate the fluorescence brightness of negatively charged nitrogen-vacancy (NV(-)) centers in nanodiamonds through magnetic resonance techniques. Using a CCD camera, this "deterministic emitter switch microscopy" (DESM) technique enables super-resolution imaging with localization down to 12 nm across a 35 × 35 μm(2) area. DESM is particularly well suited for biological applications such as multispectral particle tracking since fluorescent nanodiamonds are not only cytocompatible but also nonbleaching and bright. We observe fluorescence count rates exceeding 1.5 × 10(6) photons per second from single NV(-) centers at saturation. When combined with emerging NV(-)-based techniques for sensing magnetic and electric fields, DESM opens the door to rapid, super-resolution imaging for tracking and sensing applications in the life and physical sciences.

  15. Spin-dependent electron momentum densities in Co 2FeGa studied by Compton scattering

    NASA Astrophysics Data System (ADS)

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

    2001-06-01

    The spin density of Heusler alloy Co 2FeGa, has been studied using the Compton scattering technique with 274 keV circularly polarized synchrotron radiation in the high energy inelastic scattering beamline (BL08W), at SPring-8, Japan. The magnetic Compton profiles along the two principal directions [1 1 0] and [1 1 1] were measured. The spin profiles shows a good agreement with our FLAPW-GGA results, where the theoretical results were based on the ferromagnetic ground state. The 3d spin moment at the Co and the Fe site was found to be in excellent agreement with the earlier reported neutron diffraction measurements.

  16. Experimental observation of spin-dependent electron many-body effects in CdTe

    SciTech Connect

    Horodyská, P.; Němec, P. Novotný, T.; Trojánek, F.; Malý, P.

    2014-08-07

    In semiconductors, the spin degree of freedom is usually disregarded in the theoretical treatment of electron many-body effects such as band-gap renormalization and screening of the Coulomb enhancement factor. Nevertheless, as was observed experimentally in GaAs, not only the single-particle phase-space filling but also many-body effects are spin sensitive. In this paper, we report on time- and polarization-resolved differential transmission pump-probe measurements in CdTe, which has the same zincblende crystal structure but different material parameters compared to that of GaAs. We show experimentally that at room temperature in CdTe—unlike in GaAs—the pump-induced decrease of transmission due to the band-gap renormalization can even exceed the transmission increase due to the phase-space filling, which enables to measure directly the spin-sensitivity of the band-gap renormalization. We also observed that the influence of the band-gap renormalization is more prominent at low temperatures.

  17. Experiments of Search for Neutron Electric Dipole Moment and Spin-Dependent Short-Range Force

    NASA Astrophysics Data System (ADS)

    Zheng, Wangzhi

    It is of great importance to identify new sources of discrete symmetry violations because it can explain the baryon number asymmetry of our universe and also test the validity of various models beyond the standard model. Neutron Electric Dipole Moment (nEDM) and short-range force are such candidates for the new sources of P&T violations. A new generation nEDM experiment was proposed in USA in 2002, aiming at improving the current nEDM upperlimit by two orders of magnitude. Polarized 3He is crucial in this experiment and Duke is responsible for the 3He injection, measurements of 3He nuclear magnetic resonance (NMR) signal and some physics properties related to polarized 3He. A Monte-Carlo simulation is used to simulate the entire 3He injection process in order to study whether polarized 3He can be successfully delivered to the measurement cell. Our simulation result shows that it is achievable to maintain more than 95% polarization after 3He atoms travel through very complicated paths in the presence of non-uniform magnetic fiels. We also built an apparatus to demonstrate that the 3He precession signal can be measured under the nEDM experimental conditions using the Superconducting Quantum Interference Device (SQUID). Based on the measurement result in our lab, we project that the signal-to-noise ratio in the nEDM experiment will be at least 10. During this SQUID test, two interesting phenomena were discovered. One is the pressure dependence of the T1 of the polarized 3He which has never been reported before. The other is the discrepancy between the theoretically predicted T2 and the experimentally measured T2 of the 3He precession signal. To investigate these two interesting phenomena, two dedicated experiments were built, and two papers have been published in Physical Review A. In addition to the nEDM experiment, polarized 3He is also used in the search for the exotic short-range force. The high pressure 3He cell used in this experiment has a very thin window (˜250 mum) to maximize the effect from the force. We demonstrate that our new method could improve the current best experimental limit by two orders of magnitude. A rapid communication demonstrating the technique and the result was published in Physical Review D.

  18. Interface-engineered spin-dependent transport in perpendicular Co/Pt multilayers

    NASA Astrophysics Data System (ADS)

    Jiang, Shao-Long; Yang, Guang; Teng, Jiao; Guo, Qi-Xun; Li, Lei-Lei; Yu, Guang-Hua

    2016-11-01

    The improvement of anomalous Hall effect (AHE) has been obtained through the introduction of a Ta metallic layer at the Co/MgO interface in perpendicular [Pt/Co]3/MgO multilayers. It is exhibited that the saturation anomalous Hall resistivity is 42% larger than that in Co/Pt multilayers without Ta insertion. More meaningfully, thermally stable AHE feature is gained in perpendicular [Pt/Co]3/Ta/MgO multilayers despite Co-Pt interdiffusion. The AHE is enhanced for sample [Pt/Co]3/Ta/MgO after annealing, mainly due to the enhancement of the side-jump and intrinsic contributions.

  19. Protein-Inhibitor Interaction Studies Using NMR

    PubMed Central

    Ishima, Rieko

    2015-01-01

    Solution-state NMR has been widely applied to determine the three-dimensional structure, dynamics, and molecular interactions of proteins. The designs of experiments used in protein NMR differ from those used for small-molecule NMR, primarily because the information available prior to an experiment, such as molecular mass and knowledge of the primary structure, is unique for proteins compared to small molecules. In this review article, protein NMR for structural biology is introduced with comparisons to small-molecule NMR, such as descriptions of labeling strategies and the effects of molecular dynamics on relaxation. Next, applications for protein NMR are reviewed, especially practical aspects for protein-observed ligand-protein interaction studies. Overall, the following topics are described: (1) characteristics of protein NMR, (2) methods to detect protein-ligand interactions by NMR, and (3) practical aspects of carrying out protein-observed inhibitor-protein interaction studies. PMID:26361636

  20. Sibling interaction.

    PubMed

    Balsam, Rosemary H

    2013-01-01

    Sibling interactions traditionally were conceived psychoanalytically in "vertical" and parentified oedipal terms and overlooked in their own right, for complicated reasons (Colonna and Newman 1983). Important work has been done to right this, from the 1980s and onward, with conferences and writings. Juliet Mitchell's 2000 and, in particular, her 2003 books, for example, have brought "lateral" sibling relations forcefully to the forefront of insights, especially about sex and violence, with the added interdisciplinary impact of illuminating upheaval in global community interactions as well as having implications for clinicians. A clinical example from the analysis of an adult woman with a ten-years-younger sister will show here how we need both concepts to help us understand complex individual psychic life. The newer "lateral" sibling emphasis, including Mitchell's "Law of the Mother" and "seriality," can be used to inform the older "vertical" take, to enrich the full dimensions of intersubjective oedipal and preoedipal reciprocities that have been foundational in shaping that particular analysand's inner landscape. Some technical recommendations for heightening sensitivity to the import of these dynamics will be offered along the way here, by invoking Hans Loewald's useful metaphor of the analytic situation as theater.

  1. Strong Spin-Orbit Interaction of Light in Plasmonic Nanostructures and Nanocircuits

    NASA Astrophysics Data System (ADS)

    Pan, Deng; Wei, Hong; Gao, Long; Xu, Hongxing

    2016-10-01

    The coupling between the spin and orbital degrees of freedom of photons is usually very weak, but recent studies have shown that this spin-orbit interaction (SOI) can be easily detected in metal structures. Here we show how the SOI of light is enhanced in plasmonic metal nanostructures, explore the underlying mechanism for this effect, and further demonstrate how it could potentially be harnessed for nanophotonic applications. Specifically, we show that the scattering of circularly polarized photons by a single metal nanosphere causes light to propagate along sharply twisted chiral trajectories near the nanosphere, thus revealing a strong SOI in the near field of surface plasmons. We find similar spin-dependent trajectories of light induced by a strong SOI also in the near field of surface plasmons generated on the tip of a metal nanowire. We utilize this strong SOI to for the first time experimentally realize spin sorting of photons in a compact plasmonic nanocircuit. The findings offer insights into how the SOI of light can be enhanced and explored for a new degree of freedom in plasmonic nanocircuits and future spin-controlled nanophotonic devices.

  2. Cosmic Interactions

    NASA Astrophysics Data System (ADS)

    2008-01-01

    An image based on data taken with ESO's Very Large Telescope reveals a triplet of galaxies intertwined in a cosmic dance. ESO PR Photo 02/08 ESO PR Photo 02/08 NGC 7173, 7174, and 7176 The three galaxies, catalogued as NGC 7173 (top), 7174 (bottom right) and 7176 (bottom left), are located 106 million light-years away towards the constellation of Piscis Austrinus (the 'Southern Fish'). NGC 7173 and 7176 are elliptical galaxies, while NGC 7174 is a spiral galaxy with quite disturbed dust lanes and a long, twisted tail. This seems to indicate that the two bottom galaxies - whose combined shape bears some resemblance to that of a sleeping baby - are currently interacting, with NGC 7176 providing fresh material to NGC 7174. Matter present in great quantity around the triplet's members also points to the fact that NGC 7176 and NGC 7173 have interacted in the past. Astronomers have suggested that the three galaxies will finally merge into a giant 'island universe', tens to hundreds of times as massive as our own Milky Way. ESO PR Photo 02/08 ESO PR Photo 02b/08 NGC 7173, 7174, and 7176 The triplet is part of a so-called 'Compact Group', as compiled by Canadian astronomer Paul Hickson in the early 1980s. The group, which is the 90th entry in the catalogue and is therefore known as HCG 90, actually contains four major members. One of them - NGC 7192 - lies above the trio, outside of this image, and is another peculiar spiral galaxy. Compact groups are small, relatively isolated, systems of typically four to ten galaxies in close proximity to one another. Another striking example is Robert's Quartet. Compact groups are excellent laboratories for the study of galaxy interactions and their effects, in particular the formation of stars. As the striking image reveals, there are many other galaxies in the field. Some are distant ones, while others seem to be part of the family. Studies made with other telescopes have indeed revealed that the HCG 90 group contains 16 members

  3. Multiple sclerosis: the elevated antibody response to Epstein-Barr virus primarily targets, but is not confined to, the glycine-alanine repeat of Epstein-Barr nuclear antigen-1.

    PubMed

    Ruprecht, Klemens; Wunderlich, Benjamin; Gieß, René; Meyer, Petra; Loebel, Madlen; Lenz, Klaus; Hofmann, Jörg; Rosche, Berit; Wengert, Oliver; Paul, Friedemann; Reimer, Ulf; Scheibenbogen, Carmen

    2014-07-15

    Patients with multiple sclerosis (MS) have elevated antibodies against Epstein-Barr virus (EBV), but data on the epitope-resolved specificity of these antibodies are scarce. Using a peptide microarray containing 1465 peptides representing 8 full-length EBV proteins, we identified higher (p<0.001) antibody reactivities to 39 EBV-peptides in MS patients (n=29) compared to healthy controls (n=22). Seventeen of the 39 peptides were from EBNA-1 and 13 located within the glycine-alanine repeat of EBNA-1. Further reactivities were directed against EBNA-3, EBNA-4, EBNA-6, VP26, and LMP1. Thus, antibodies against EBV in MS patients primarily target, but are not confined to, the glycine-alanine repeat of EBNA-1.

  4. Electroweak interactions

    SciTech Connect

    Bjorken, J.D.

    1980-10-01

    A point of view of the electroweak interaction is presented. It begins phenomenologically and moves in stages toward the conventional gauge theory formalism containing elementary scalar Higgs-fields and then beyond. The purpose in so doing is that the success of the standard SU(2) x U(1) theory in accounting for low energy phenomena need not automatically imply success at high energies. It is deemed unlikely by most theorists that the predicted W/sup + -/ or Z/sup 0/ does not exist or does not have the mass and/or couplings anticipated in the standard model. However, the odds that the standard predictions will work are not 100%. Therefore there is some reason to look at the subject as one would were he forced by a wrong experimental outcome - to go back to fundamentals and ascertain what is the minimal amount of theory necessary to account for the data.

  5. Topological defect formation in rotating binary dipolar Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-Fei; Han, Wei; Jiang, Hai-Feng; Liu, Wu-Ming; Saito, Hiroki; Zhang, Shou-Gang

    2016-12-01

    We investigate the topological defects and spin structures of a rotating binary Bose-Einstein condensate, which consists of both dipolar and scalar bosonic atoms confined in spin-dependent optical lattices, for an arbitrary orientation of the dipoles with respect to their plane of motion. Our results show that the tunable dipolar interaction, especially the orientation of the dipoles, can be used to control the direction of stripe phase and its related half-vortex sheets. In addition, it can also be used to obtain a regular arrangement of various topological spin textures, such as meron, circular and cross disgyration spin structures. We point out that such topological defects and regular arrangement of spin structures arise primarily from the long-range and anisotropic nature of dipolar interaction and its competition with the spin-dependent optical lattices and rotation.

  6. Designing "Interaction": How Do Interaction Design Students Address Interaction?

    ERIC Educational Resources Information Center

    Karlgren, Klas; Ramberg, Robert; Artman, Henrik

    2016-01-01

    Interaction design is usually described as being concerned with interactions with and through artifacts but independent of a specific implementation. Design work has been characterized as a conversation between the designer and the situation and this conversation poses a particular challenge for interaction design as interactions can be elusive…

  7. Cloud Interactions

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 1 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth.

    Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms.

    This image was acquired during mid-spring near the North Pole. The linear water-ice clouds are now regional in extent and often interact with neighboring cloud system, as seen in this image. The bottom of the image shows how the interaction can destroy the linear nature. While the surface is still visible through most of the clouds, there is evidence that dust is also starting to enter the atmosphere.

    Image information: VIS instrument. Latitude 68.4, Longitude 258.8 East (101.2 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration

  8. Effects of Sudden, Mass School Desegregation on Interracial Interaction and Attitudes in One Southern City.

    ERIC Educational Resources Information Center

    Silverman, Irwin; Shaw, Marvin E.

    The authors concern themselves primarily with 2 effects of a school desegregation plan during the semester of its inception in Gainesville, Florida. One deals with the amount of interaction between blacks and whites on the school grounds; the other concerns their attitudes toward each other. Interaction was measured, through observation during the…

  9. Characteristics of Interactive Oral and Computer-Mediated Peer Group Talk and Its Influence on Revision.

    ERIC Educational Resources Information Center

    Hewett, Beth L.

    2000-01-01

    Details a functional and qualitative study of interactive oral and computer-mediated communication (CMC)-generated (Norton "Connect") peer response group talk and its influence on revision. Finds the interactive peer groups in both environments talked primarily about their writing; however, the talk had different qualities when students used…

  10. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies

    SciTech Connect

    Not Available

    1990-10-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988--91. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons that we have been involved with for more than ten years. Its purpose has been to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The give complex isospin-one amplitudes have been fairly well determined, partly as a result of this work. Our work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues our studies of this interaction in regions where it has not been well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where our data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei.

  11. The fundamental ribosomal RNA transcription initiation factor-IB (TIF-IB, SL1, factor D) binds to the rRNA core promoter primarily by minor groove contacts.

    PubMed

    Geiss, G K; Radebaugh, C A; Paule, M R

    1997-11-14

    Acanthamoeba castellanii transcription initiation factor-IB (TIF-IB) is the TATA-binding protein-containing transcription factor that binds the rRNA promoter to form the committed complex. Minor groove-specific drugs inhibit TIF-IB binding, with higher concentrations needed to disrupt preformed complexes because of drug exclusion by bound TIF-IB. TIF-IB/DNA interactions were mapped by hydroxyl radical and uranyl nitrate footprinting. TIF-IB contacts four minor grooves in its binding site. TIF-IB and DNA wrap around each other in a right-handed superhelix of high pitch, so the upstream and downstream contacts are on opposite faces of the helix. Dimethyl sulfate protection assays revealed limited contact with a few guanines in the major groove. This detailed analysis suggests significant DNA conformation dependence of the interaction.

  12. Prostaglandin E2-induced up-regulation of c-fos messenger ribonucleic acid is primarily mediated by 3',5'-cyclic adenosine monophosphate in MC3T3-E1 osteoblasts

    NASA Technical Reports Server (NTRS)

    Fitzgerald, J.; Dietz, T. J.; Hughes-Fulford, M.

    2000-01-01

    The mechanism by which the proto-oncogene, c-fos, is up-regulated in response to PGE2 in the mouse osteoblastic (MC3T3-E1) cell line was investigated using RT-PCR. c-fos messenger RNA up-regulation by dmPGE2 is rapid, starting 10 min post stimulation, and transient. The specific protein kinase A (PKA) inhibitor, H89, inhibited c-fos induction. Moreover, down-regulation of protein kinase C (PKC) activity by chronic TPA treatment had no effect on the induction of c-fos by dmPGE2. We conclude that up-regulation of c-fos by dmPGE2 is primarily dependent on PKA in MC3T3-E1 osteoblasts. In S49 lymphoma wild-type but not S49 cyc- cells, which are deficient in cAMP signaling, dmPGE2 up-regulates c-fos and increases cell growth compared with unstimulated cells. Thus in S49 lymphoma cells, c-fos induction by PGE2 is also dependent on cAMP signaling. The minimal c-fos promoter region required for dmPGE2-induced expression was identified by transfecting c-fos promoter deletion constructs coupled to the chloramphenicol acetyltransferase (CAT) reporter gene into Vero cells. Transfection of a plasmid containing 99 bp c-fos proximal promoter was sufficient to direct c-fos/CAT expression following stimulation with dmPGE2. Because induction of c-fos is mediated by cAMP, these data are consistent with activation of c-fos via the CRE/ATF cis element.

  13. Comparative study of smoke condensates from 1R4F cigarettes that burn tobacco versus ECLIPSE cigarettes that primarily heat tobacco in the SENCAR mouse dermal tumor promotion assay.

    PubMed

    Meckley, Daniel R; Hayes, Johnnie R; Van Kampen, K R; Ayres, Paul H; Mosberg, Arnold T; Swauger, James E

    2004-05-01

    Numerous chemical and toxicological studies indicate that smoke from ECLIPSE, a cigarette that primarily heats rather than burns tobacco, is simplified and reduced in specific chemicals believed to be associated with smoking-related diseases, and demonstrates reduced smoke toxicity and biological activity in vitro when compared to conventional tobacco burning cigarettes. These data led to the hypothesis that cigarette smoke condensate (CSC) from ECLIPSE should have lower tumorigenicity than 1R4F condensate in the SENCAR mouse dermal tumor promotion assay. Female SENCAR mice were initiated with a single topical application of 7,12-dimethylbenz[a]anthracene (DMBA) followed by promotion with ECLIPSE or 1R4F CSC. Dermal application of 10, 20, or 40 mg ECLIPSE or 1R4F CSC three times/week for 29 weeks did not alter body weights, survival or other indicators of subchronic toxicity. In DMBA-initiated mice, there were significant increases in both the number of microscopically confirmed tumor-bearing animals and total number of microscopically confirmed dermal tumors at all 1R4F CSC doses and the high-dose ECLIPSE CSC. However, the number of ECLIPSE tumor-bearing animals were reduced 83%, 93% and 67% at the low-, mid- and high-doses, respectively, compared to the 1R4F. Similarly, the total number of dermal tumors was reduced 91%, 94% and 87% at the low-, mid- and high-dose, respectively, compared to the 1R4F CSC. ECLIPSE CSC demonstrated dramatic reductions in dermal tumor promotion potential compared to 1R4F CSC.

  14. Signal Use by Octopuses in Agonistic Interactions.

    PubMed

    Scheel, David; Godfrey-Smith, Peter; Lawrence, Matthew

    2016-02-08

    Cephalopods show behavioral parallels to birds and mammals despite considerable evolutionary distance [1, 2]. Many cephalopods produce complex body patterns and visual signals, documented especially in cuttlefish and squid, where they are used both in camouflage and a range of interspecific interactions [1, 3-5]. Octopuses, in contrast, are usually seen as solitary and asocial [6, 7]; their body patterns and color changes have primarily been interpreted as camouflage and anti-predator tactics [8-12], though the familiar view of the solitary octopus faces a growing list of exceptions. Here, we show by field observation that in a shallow-water octopus, Octopus tetricus, a range of visible displays are produced during agonistic interactions, and these displays correlate with the outcome of those interactions. Interactions in which dark body color by an approaching octopus was matched by similar color in the reacting octopus were more likely to escalate to grappling. Darkness in an approaching octopus met by paler color in the reacting octopus accompanied retreat of the paler octopus. Octopuses also displayed on high ground and stood with spread web and elevated mantle, often producing these behaviors in combinations. This study is the first to document the systematic use of signals during agonistic interactions among octopuses. We show prima facie conformity of our results to an influential model of agonistic signaling [13]. These results suggest that interactions have a greater influence on octopus evolution than has been recognized and show the importance of convergent evolution in behavioral traits.

  15. Measuring interactivity on tobacco control websites.

    PubMed

    Freeman, Becky; Chapman, Simon

    2012-08-01

    With the increased reach of Web 2.0, Internet users expect webpages to be interactive. No studies have been conducted to assess whether tobacco control-relevant sites have implemented these features. The authors conducted an analysis of an international sample of tobacco control-relevant websites to determine their level of interactivity. The sample included 68 unique websites selected from Google searches in 5 countries, on each country's Google site, using the term smoking. The 68 sites were analyzed for 10 categories of interactive tools. The most common type of interactive content found on 46 (68%) of sites was for multimedia featuring content that was not primarily text based, such as photo galleries, videos, or podcasts. Only 11 (16%) websites-outside of media sites-allowed people to interact and engage with the site owners and other users by allowing posting comments on content and/or hosting forums/discussions. Linkages to social networking sites were low: 17 pages (25%) linked to Twitter, 15 (22%) to Facebook, and 11 (16%) to YouTube. Interactivity and connectedness to online social media appears to still be in its infancy among tobacco control-relevant sites.

  16. Categorizing Biases in High-Confidence High-Throughput Protein-Protein Interaction Data Sets

    DTIC Science & Technology

    2011-01-01

    interaction data sets derived from affinity purification/mass spec- trometry, protein-fragment complementation assay, and yeast two-hybrid experiments . The...characteristics. These differences were primarily a func- tion of the deployed experimental technologies used to recover these interactions. This affected the total...the protein interaction data within their experimental or cellular con- text provided the best avenue for overcoming biases and inferring biological

  17. Formation et interaction (Teacher Education and Interaction).

    ERIC Educational Resources Information Center

    Bertocchini, Paola; Costanzo, Edwige

    1989-01-01

    Effective interaction is as important in inservice education programs for language teachers as it is in the foreign language classroom. Techniques are described for improving the quality of interaction in teacher workshops through simulation exercises. (MSE)

  18. Spin-resolved Andreev transport through a double quantum-dot system: Role of the Rashba spin-orbit interaction

    SciTech Connect

    Nian, L. L.; Zhang, Lei; Tang, Fu-Rong; Xue, L. P.; Zhang, Rong; Bai, Long

    2014-06-07

    Using the nonequilibrium Green's function technique, spin-related Andreev tunneling through a double quantum-dot device attached to a ferromagnetic and a superconducting leads in the presence of the Rashba spin-orbit interaction is explored. We derive the general formulas of spin-related currents, which provide an insight into the Andreev reflection. Our study demonstrates that the spin-polarized Andreev reflection can be achieved, even the pure spin injection may be realized via the spin-orbit coupling and the Zeeman field. The currents show the interesting step-like behaviors and the pronounced rectification effect in the Andreev reflection regime, and the magnitude of currents can be enhanced with increasing the spin polarization of the ferromagnetic electrode. The strong Zemann field and the relative temperature are not favor of the spin-related Andreev transport; moreover, the existence of negative differential conductance of the spin-polarized current under certain conditions is observed and analyzed. These results provide the new ways to manipulate the spin-dependent transport.

  19. beta-adrenergic receptors primarily are located on the dendrites of granule cells and interneurons but also are found on astrocytes and a few presynaptic profiles in the rat dentate gyrus.

    PubMed

    Milner, T A; Shah, P; Pierce, J P

    2000-06-01

    In the rat dentate gyrus, beta-adrenergic receptor (beta-AR) activation is thought to be important in mediating the effects of norepinephrine (NE). beta-AR-immunoreactivity (beta-AR-I) was localized in this study by light and electron microscopy in the rat dentate gyrus by using two previously characterized antibodies to the beta-AR. By light microscopy, dense beta-AR-I was observed in the somata of granule cells and a few hilar interneurons. Diffuse and slightly granular beta-AR-I was found in all laminae, although it was most noticeable in the molecular layer. Ultrastructurally, the cytoplasm of granule cell and interneuronal perikarya (some of which contained parvalbumin immunoreactivity) contained beta-AR-I. beta-AR-I was associated primarily with the endoplasmic reticula; however, a few patches were observed near the plasmalemma. Quantitative analysis revealed that the greatest proportion of beta-AR-labeled profiles was found in the molecular layer. The majority of beta-AR-labeled profiles were either dendritic or astrocytic. In dendritic profiles, beta-AR-I was prominent near postsynaptic densities in large dendrites, many of which originated from granule cell somata. Moreover, some beta-AR-I was found in dendritic spines, sometimes affiliated with the spine apparati. Astrocytic profiles with beta-AR-I were commonly found next to unlabeled terminals which formed asymmetric (excitatory-type) synapses with dendritic spines. Additionally, beta-AR-I was observed in a few unmyelinated axons and axon terminals, many of which formed synapses with dendritic spines. Dual-labeling studies revealed that axons and axon terminals containing tyrosine hydroxylase (TH), the catecholamine synthesizing enzyme, often were near both neuronal and glial profiles containing beta-AR-I. These studies demonstrate that hippocampal beta-AR-I is localized: 1) principally in postsynaptic sites on granule cells and a few interneurons (some of which were basket cells); and 2) in glial

  20. Nature and consequences of non-covalent interactions between flavonoids and macronutrients in foods.

    PubMed

    Bordenave, Nicolas; Hamaker, Bruce R; Ferruzzi, Mario G

    2014-01-01

    Many of the potential health benefits of flavonoids have been associated with their specific chemical and biological properties including their ability to interact and bind non-covalently to macronutrients in foods. While flavonoid-protein interactions and binding have been the subject of intensive study, significantly less is understood about non-covalent interactions with carbohydrates and lipids. These interactions with macronutrients are likely to impact both the flavonoid properties in foods, such as their radical scavenging activity, and the food or beverage matrix itself, including their taste, texture and other sensorial properties. Overall, non-covalent binding of flavonoids with macronutrients is primarily driven by van der Waals interactions. From the flavonoid perspective, these interactions are modulated by characteristics such as degree of polymerization, molecular flexibility, number of external hydroxyl groups, or number of terminal galloyl groups. From the macronutrient standpoint, electrostatic and ionic interactions are generally predominant with carbohydrates, while hydrophobic interactions are generally predominant with lipids and mainly limited to interactions with flavonols. All of these interactions are involved in flavonoid-protein interactions. While primarily associated with undesirable characteristics in foods and beverages, such as astringency, negative impact on macronutrient digestibility and hazing, more recent efforts have attempted to leverage these interactions to develop controlled delivery systems or strategies to enhance flavonoids bioavailability. This paper aims at reviewing the fundamental bases for non-covalent interactions, their occurrence in food and beverage systems and their impact on the physico-chemical, organoleptic and some nutritional properties of food.

  1. Bar-spheroid interaction in galaxies

    NASA Technical Reports Server (NTRS)

    Hernquist, Lars; Weinberg, Martin D.

    1992-01-01

    N-body simulation and linear analysis is employed to investigate the secular evolution of barred galaxies, with emphasis on the interaction between bars and spheroidal components of galaxies. This interaction is argued to drive secular transfer of angular momentum from bars to spheroids, primarily through resonant coupling. A moderately strong bar, having mass within corotation about 0.3 times the enclosed spheroid mass, is predicted to shed all its angular momentum typically in less than about 10 exp 9 yr. Even shorter depletion time scales are found for relatively more massive bars. It is suggested either that spheroids around barred galaxies are structured so as to inhibit strong coupling with bars, or that bars can form by unknown processes long after disks are established. The present models reinforce the notion that bars can drive secular evolution in galaxies.

  2. Yakima River Species Interactions Studies, Annual Report 1993.

    SciTech Connect

    Pearsons, Todd N.

    1994-12-01

    Species interactions research was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. Data have been collected prior to supplementation to characterize the rainbow trout population, predict the potential interactions that may occur as a result of supplementation, and develop methods to monitor interactions. Major topics of this report are associated with the life history of rainbow trout, interactions experimentation, and methods for sampling. This report is organized into nine chapters with a general introduction preceding the first chapter and a general discussion following the last chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1 and December 31, 1993 in the upper Yakima basin above Roza Dam, however these data were compared to data from previous years to identify preliminary trends and patterns. Major preliminary findings from each of the chapters included in this report are described.

  3. A Challenge for the Developer: Issues of Interactivity and Linguistic-Cognitive Appropriateness in English Language Learning

    ERIC Educational Resources Information Center

    Poon, Anita Y. K.

    2003-01-01

    It is argued that language learning ought to be interactive. The traditional language classroom provides a favourable interactive situation for language learners. By contrast, the distance education mode is limited in some ways regarding language learning. Necessarily, distance education involves, primarily, self-learning. Face-to-face learning…

  4. Identification of brain-specific angiogenesis inhibitor 2 as an interaction partner of glutaminase interacting protein

    SciTech Connect

    Zencir, Sevil; Ovee, Mohiuddin; Dobson, Melanie J.; Banerjee, Monimoy; Topcu, Zeki; Mohanty, Smita

    2011-08-12

    Highlights: {yields} Brain-specific angiogenesis inhibitor 2 (BAI2) is a new partner protein for GIP. {yields} BAI2 interaction with GIP was revealed by yeast two-hybrid assay. {yields} Binding of BAI2 to GIP was characterized by NMR, CD and fluorescence. {yields} BAI2 and GIP binding was mediated through the C-terminus of BAI2. -- Abstract: The vast majority of physiological processes in living cells are mediated by protein-protein interactions often specified by particular protein sequence motifs. PDZ domains, composed of 80-100 amino acid residues, are an important class of interaction motif. Among the PDZ-containing proteins, glutaminase interacting protein (GIP), also known as Tax Interacting Protein TIP-1, is unique in being composed almost exclusively of a single PDZ domain. GIP has important roles in cellular signaling, protein scaffolding and modulation of tumor growth and interacts with a number of physiological partner proteins, including Glutaminase L, {beta}-Catenin, FAS, HTLV-1 Tax, HPV16 E6, Rhotekin and Kir 2.3. To identify the network of proteins that interact with GIP, a human fetal brain cDNA library was screened using a yeast two-hybrid assay with GIP as bait. We identified brain-specific angiogenesis inhibitor 2 (BAI2), a member of the adhesion-G protein-coupled receptors (GPCRs), as a new partner of GIP. BAI2 is expressed primarily in neurons, further expanding GIP cellular functions. The interaction between GIP and the carboxy-terminus of BAI2 was characterized using fluorescence, circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy assays. These biophysical analyses support the interaction identified in the yeast two-hybrid assay. This is the first study reporting BAI2 as an interaction partner of GIP.

  5. PIC: Protein Interactions Calculator

    PubMed Central

    Tina, K. G.; Bhadra, R.; Srinivasan, N.

    2007-01-01

    Interactions within a protein structure and interactions between proteins in an assembly are essential considerations in understanding molecular basis of stability and functions of proteins and their complexes. There are several weak and strong interactions that render stability to a protein structure or an assembly. Protein Interactions Calculator (PIC) is a server which, given the coordinate set of 3D structure of a protein or an assembly, computes various interactions such as disulphide bonds, interactions between hydrophobic residues, ionic interactions, hydrogen bonds, aromatic–aromatic interactions, aromatic–sulphur interactions and cation–π interactions within a protein or between proteins in a complex. Interactions are calculated on the basis of standard, published criteria. The identified interactions between residues can be visualized using a RasMol and Jmol interface. The advantage with PIC server is the easy availability of inter-residue interaction calculations in a single site. It also determines the accessible surface area and residue-depth, which is the distance of a residue from the surface of the protein. User can also recognize specific kind of interactions, such as apolar–apolar residue interactions or ionic interactions, that are formed between buried or exposed residues or near the surface or deep inside. PMID:17584791

  6. PIC: Protein Interactions Calculator.

    PubMed

    Tina, K G; Bhadra, R; Srinivasan, N

    2007-07-01

    Interactions within a protein structure and interactions between proteins in an assembly are essential considerations in understanding molecular basis of stability and functions of proteins and their complexes. There are several weak and strong interactions that render stability to a protein structure or an assembly. Protein Interactions Calculator (PIC) is a server which, given the coordinate set of 3D structure of a protein or an assembly, computes various interactions such as disulphide bonds, interactions between hydrophobic residues, ionic interactions, hydrogen bonds, aromatic-aromatic interactions, aromatic-sulphur interactions and cation-pi interactions within a protein or between proteins in a complex. Interactions are calculated on the basis of standard, published criteria. The identified interactions between residues can be visualized using a RasMol and Jmol interface. The advantage with PIC server is the easy availability of inter-residue interaction calculations in a single site. It also determines the accessible surface area and residue-depth, which is the distance of a residue from the surface of the protein. User can also recognize specific kind of interactions, such as apolar-apolar residue interactions or ionic interactions, that are formed between buried or exposed residues or near the surface or deep inside.

  7. Origin and Magnitude of `Designer' Spin-Orbit Interaction in Graphene on Semiconducting Transition Metal Dichalcogenides

    NASA Astrophysics Data System (ADS)

    Wang, Zhe; Ki, Dong-Keun; Khoo, Jun Yong; Mauro, Diego; Berger, Helmuth; Levitov, Leonid S.; Morpurgo, Alberto F.

    2016-10-01

    We use a combination of experimental techniques to demonstrate a general occurrence of spin-orbit interaction (SOI) in graphene on transition metal dichalcogenide (TMD) substrates. Our measurements indicate that SOI is ultrastrong and extremely robust, despite it being merely interfacially induced, with neither graphene nor the TMD substrates changing their structure. This is found to be the case irrespective of the TMD material used, of the transport regime, of the carrier type in the graphene band, or of the thickness of the graphene multilayer. Specifically, we perform weak antilocalization (WAL) measurements as the simplest and most general diagnostic of SOI, and we show that the spin relaxation time is very short (approximately 0.2 ps or less) in all cases regardless of the elastic scattering time, whose value varies over nearly 2 orders of magnitude. Such a short spin-relaxation time strongly suggests that the SOI originates from a modification of graphene band structure. We confirmed this expectation by measuring a gate-dependent beating, and a corresponding frequency splitting, in the low-field Shubnikov-de Haas magnetoresistance oscillations in high-quality bilayer graphene devices on WSe2 . These measurements provide an unambiguous diagnostic of a SOI-induced splitting in the electronic band structure, and their analysis allows us to determine the SOI coupling constants for the Rashba term and the so-called spin-valley coupling term, i.e., the terms that were recently predicted theoretically for interface-induced SOI in graphene. The magnitude of the SOI splitting is found to be on the order of 10 meV, more than 100 times greater than the SOI intrinsic to graphene. Both the band character of the interfacially induced SOI and its robustness and large magnitude make graphene-on-TMD a promising system to realize and explore a variety of spin-dependent transport phenomena, such as, in particular, spin-Hall and valley-Hall topological insulating states.

  8. THE METALLICITY EVOLUTION OF INTERACTING GALAXIES

    SciTech Connect

    Torrey, Paul; Hernquist, Lars; Cox, T. J.; Kewley, Lisa

    2012-02-10

    Nuclear inflows of metal-poor interstellar gas triggered by galaxy interactions can account for the systematically lower central oxygen abundances observed in local interacting galaxies. Here, we investigate the metallicity evolution of a large set of simulations of colliding galaxies. Our models include cooling, star formation, feedback, and a new stochastic method for tracking the mass recycled back to the interstellar medium from stellar winds and supernovae. We study the influence of merger-induced inflows, enrichment, gas consumption, and galactic winds in determining the nuclear metallicity. The central metallicity is primarily a competition between the inflow of low-metallicity gas and enrichment from star formation. An average depression in the nuclear metallicity of {approx}0.07 is found for gas-poor disk-disk interactions. Gas-rich disk-disk interactions, on the other hand, typically have an enhancement in the central metallicity that is positively correlated with the gas content. The simulations fare reasonably well when compared to the observed mass-metallicity and separation-metallicity relationships, but further study is warranted.

  9. Interactive visualization to advance earthquake simulation

    USGS Publications Warehouse

    Kellogg, L.H.; Bawden, G.W.; Bernardin, T.; Billen, M.; Cowgill, E.; Hamann, B.; Jadamec, M.; Kreylos, O.; Staadt, O.; Sumner, D.

    2008-01-01

    The geological sciences are challenged to manage and interpret increasing volumes of data as observations and simulations increase in size and complexity. For example, simulations of earthquake-related processes typically generate complex, time-varying data sets in two or more dimensions. To facilitate interpretation and analysis of these data sets, evaluate the underlying models, and to drive future calculations, we have developed methods of interactive visualization with a special focus on using immersive virtual reality (VR) environments to interact with models of Earth's surface and interior. Virtual mapping tools allow virtual "field studies" in inaccessible regions. Interactive tools allow us to manipulate shapes in order to construct models of geological features for geodynamic models, while feature extraction tools support quantitative measurement of structures that emerge from numerical simulation or field observations, thereby enabling us to improve our interpretation of the dynamical processes that drive earthquakes. VR has traditionally been used primarily as a presentation tool, albeit with active navigation through data. Reaping the full intellectual benefits of immersive VR as a tool for scientific analysis requires building on the method's strengths, that is, using both 3D perception and interaction with observed or simulated data. This approach also takes advantage of the specialized skills of geological scientists who are trained to interpret, the often limited, geological and geophysical data available from field observations. ?? Birkhaueser 2008.

  10. INCA- INTERACTIVE CONTROLS ANALYSIS

    NASA Technical Reports Server (NTRS)

    Bauer, F. H.

    1994-01-01

    The Interactive Controls Analysis (INCA) program was developed to provide a user friendly environment for the design and analysis of linear control systems, primarily feedback control systems. INCA is designed for use with both small and large order systems. Using the interactive graphics capability, the INCA user can quickly plot a root locus, frequency response, or time response of either a continuous time system or a sampled data system. The system configuration and parameters can be easily changed, allowing the INCA user to design compensation networks and perform sensitivity analysis in a very convenient manner. A journal file capability is included. This stores an entire sequence of commands, generated during an INCA session into a file which can be accessed later. Also included in INCA are a context-sensitive help library, a screen editor, and plot windows. INCA is robust to VAX-specific overflow problems. The transfer function is the basic unit of INCA. Transfer functions are automatically saved and are available to the INCA user at any time. A powerful, user friendly transfer function manipulation and editing capability is built into the INCA program. The user can do all transfer function manipulations and plotting without leaving INCA, although provisions are made to input transfer functions from data files. By using a small set of commands, the user may compute and edit transfer functions, and then examine these functions by using the ROOT_LOCUS, FREQUENCY_RESPONSE, and TIME_RESPONSE capabilities. Basic input data, including gains, are handled as single-input single-output transfer functions. These functions can be developed using the function editor or by using FORTRAN- like arithmetic expressions. In addition to the arithmetic functions, special functions are available to 1) compute step, ramp, and sinusoid functions, 2) compute closed loop transfer functions, 3) convert from S plane to Z plane with optional advanced Z transform, and 4) convert from Z

  11. Food and Drug Interactions.

    PubMed

    Choi, Jong Hwan; Ko, Chang Mann

    2017-01-01

    Natural foods and vegetal supplements have recently become increasingly popular for their roles in medicine and as staple foods. This has, however, led to the increased risk of interaction between prescribed drugs and the bioactive ingredients contained in these foods. These interactions range from pharmacokinetic interactions (absorption, distribution, metabolism, and excretion influencing blood levels of drugs) to pharmacodynamic interactions (drug effects). In a quantitative respect, these interactions occur mainly during metabolism. In addition to the systemic metabolism that occurs mainly in the liver, recent studies have focused on the metabolism in the gastrointestinal tract endothelium before absorption. Inhibition of metabolism causes an increase in the blood levels of drugs and could have adverse reactions. The food-drug interactions causing increased blood levels of drugs may have beneficial or detrimental therapeutic effects depending on the intensity and predictability of these interactions. It is therefore important to understand the potential interactions between foods and drugs should and the specific outcomes of such interactions.

  12. The GOURD model of human-computer interaction

    SciTech Connect

    Goldbogen, G.

    1996-12-31

    This paper presents a model, the GOURD model, that can be used to measure the goodness of {open_quotes}interactivity{close_quotes} of an interface design and qualifies how to improve the design. The GOURD model describes what happens to the computer and to the human during a human-computer interaction. Since the interaction is generally repeated, the traversal of the model repeatedly is similar to a loop programming structure. Because the model measures interaction over part or all of the application, it can also be used as a classifier of the part or the whole application. But primarily, the model is used as a design guide and a predictor of effectiveness.

  13. Role of viruses and bacteria-virus interactions in autoimmunity.

    PubMed

    Steed, Ashley L; Stappenbeck, Thaddeus S

    2014-12-01

    A potential role for viral and bacterial-viral interactions in the pathogenesis of autoimmune disease has been long recognized. Recently, intensive investigation has begun to decipher interactions between specific microbes with the host that contribute toward autoimmunity. This work has primarily focused on known viral and bacterial pathogens. A major challenge is to determine the role of bacteria that are typically considered as commensals as well as chronic viruses. Furthermore, equally challenging is to prove causality given the potential complexity of microbe-microbe interactions. Important initial contributions to this field have shown that specific interactions of microbes with hosts that contain a background of genetic susceptibility can play a role in autoimmune pathogenesis. In this review, we describe principles of immune tolerance with a focus on its breakdown during pathogenic as well as commensal relationships between the host and the microbial world.

  14. Interacting dark sector with transversal interaction

    SciTech Connect

    Chimento, Luis P.; Richarte, Martín G.

    2015-03-26

    We investigate the interacting dark sector composed of dark matter, dark energy, and dark radiation for a spatially flat Friedmann-Robertson-Walker (FRW) background by introducing a three-dimensional internal space spanned by the interaction vector Q and solve the source equation for a linear transversal interaction. Then, we explore a realistic model with dark matter coupled to a scalar field plus a decoupled radiation term, analyze the amount of dark energy in the radiation era and find that our model is consistent with the recent measurements of cosmic microwave background anisotropy coming from Planck along with the future constraints achievable by CMBPol experiment.

  15. The Interactional Management of Claims of Insufficient Knowledge in English Language Classrooms

    ERIC Educational Resources Information Center

    Sert, Olcay; Walsh, Steve

    2013-01-01

    This paper primarily investigates the interactional unfolding and management of "claims of insufficient knowledge" (Beach and Metzger 1997) in two English language classrooms from a multi-modal, conversation-analytic perspective. The analyses draw on a close, micro-analytic account of sequential organisation of talk as well as on various…

  16. Interactive Computer-Assisted Instruction in Acid-Base Physiology for Mobile Computer Platforms

    ERIC Educational Resources Information Center

    Longmuir, Kenneth J.

    2014-01-01

    In this project, the traditional lecture hall presentation of acid-base physiology in the first-year medical school curriculum was replaced by interactive, computer-assisted instruction designed primarily for the iPad and other mobile computer platforms. Three learning modules were developed, each with ~20 screens of information, on the subjects…

  17. Associations between Observed Mother-Adolescent Interactions and Adolescent Information Management

    ERIC Educational Resources Information Center

    Rote, Wendy M.; Smetana, Judith G.; Campione-Barr, Nicole; Villalobos, Myriam; Tasopoulos-Chan, Marina

    2012-01-01

    Associations between observed mother-adolescent interactions during a conflict task and adolescents' information management strategies were examined in 108 primarily middle class, European-American adolescents (M = 13.80 years, SD = 1.52) and their mothers. Teens who communicated more clearly disclosed more about personal and multifaceted…

  18. Family Interactions, Exposure to Violence, and Emotion Regulation: Perceptions of Children and Early Adolescents at Risk

    ERIC Educational Resources Information Center

    Houltberg, Benjamin J.; Henry, Carolyn S.; Morris, Amanda Sheffield

    2012-01-01

    This study examined the protective nature of youth reports of family interactions in relation to perceived exposure to violence and anger regulation in 84 children and early adolescents (mean age of 10.5; 7-15 years old) primarily from ethnic minority groups and living in high-risk communities in a large southwestern city. Path analysis and…

  19. Interacting with… What? Exploring Children's Social and Sensory Practices in a Science Discovery Centre

    ERIC Educational Resources Information Center

    Dicks, Bella

    2013-01-01

    This paper presents findings from a qualitative UK study exploring the social practices of schoolchildren visiting an interactive science discovery centre. It is promoted as a place for "learning through doing", but the multi-modal, ethnographic methods adopted suggest that children were primarily engaged in (1) sensory pleasure-taking…

  20. Using Interactive Writing Instruction with Kindergarten and First-Grade English Language Learners

    ERIC Educational Resources Information Center

    Williams, Cheri; Pilonieta, Paola

    2012-01-01

    In this article, written primarily for early childhood educators of young children who are learning English as another language, the authors discuss the use and educational benefits of Interactive Writing, an approach to beginning writing instruction appropriate for kindergarten and first grade children.

  1. The Effect of Naturalistic Behavior Strategies on the Quality of Social Interactions for Children with Autism

    ERIC Educational Resources Information Center

    Nichols, Susan Marie

    2012-01-01

    Autism is primarily a social disorder and deficits in social-orienting may be responsible for the failure of children with autism to initiate critical social behaviors. The purpose of this research was to improve the quality of social interactions of children with autism by implementing naturalistic behavior strategies intervention utilizing a…

  2. Gestalt Interactional Groups

    ERIC Educational Resources Information Center

    Harman, Robert L.; Franklin, Richard W.

    1975-01-01

    Gestalt therapy in groups is not limited to individual work in the presence of an audience. Describes several ways to involve gestalt groups interactionally. Interactions described focus on learning by doing and discovering, and are noninterpretive. (Author/EJT)

  3. Computerized Interactive Harness Engineering

    NASA Technical Reports Server (NTRS)

    Billitti, J. W.

    1985-01-01

    Computerized interactive harness engineering program inexpensive, interactive system for learning and using engineering approach to interconnection systems. Basically data-base system that stores information as files of individual connectors and handles wiring information in circuit groups stored as records.

  4. Interactions between magnetohydrodynamical discontinuities

    SciTech Connect

    Dai, W.; Woodward, P.R. )

    1994-11-01

    Interactions between magnetohydrodynamical (MHD) discontinuities are studied through numerical simulations for the set of one-dimensional MHD equations. The interactions include the impact of a shock on a contact discontinuity, the collision of two shocks, and the catchup of a shock over another shock. The shocks involved in the interactions may be very strong. Each shock in an interaction may be either a fast or a slow shock.

  5. AN INDIRECT SEARCH FOR WEAKLY INTERACTING MASSIVE PARTICLES IN THE SUN USING 3109.6 DAYS OF UPWARD-GOING MUONS IN SUPER-KAMIOKANDE

    SciTech Connect

    Tanaka, T.; Abe, K.; Hayato, Y.; Iida, T.; Kameda, J.; Koshio, Y.; Kouzuma, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakayama, S.; Obayashi, Y.; Sekiya, H.; Shiozawa, M.; Suzuki, Y.; Takeda, A.; Takenaga, Y.; Ueno, K.; Ueshima, K.; Yamada, S.; Collaboration: Super-Kamiokande Collaboration; and others

    2011-12-01

    We present the result of an indirect search for high energy neutrinos from Weakly Interacting Massive Particle (WIMP) annihilation in the Sun using upward-going muon (upmu) events at Super-Kamiokande. Data sets from SKI-SKIII (3109.6 days) were used for the analysis. We looked for an excess of neutrino signal from the Sun as compared with the expected atmospheric neutrino background in three upmu categories: stopping, non-showering, and showering. No significant excess was observed. The 90% C.L. upper limits of upmu flux induced by WIMPs of 100 GeV c{sup -2} were 6.4 Multiplication-Sign 10{sup -15} cm{sup -2} s{sup -1} and 4.0 Multiplication-Sign 10{sup -15} cm{sup -2} s{sup -1} for the soft and hard annihilation channels, respectively. These limits correspond to upper limits of 4.5 Multiplication-Sign 10{sup -39} cm{sup -2} and 2.7 Multiplication-Sign 10{sup -40} cm{sup -2} for spin-dependent WIMP-nucleon scattering cross sections in the soft and hard annihilation channels, respectively.

  6. Classical and quantum aspects of spin interaction in 3 d chains on a C u3N -Cu(110) molecular network

    NASA Astrophysics Data System (ADS)

    Bazhanov, D. I.; Stepanyuk, O. V.; Farberovich, O. V.; Stepanyuk, V. S.

    2016-01-01

    We present a study of the magnetic states and exchange coupling in transition-metal Mn, Fe, and Co atomic chains deposited on a self-corrugated C u3N -Cu(110) molecular network by means of first-principles calculations based on the density functional theory. The various adsorption sites on a bumping area of a self-corrugated C u3N layer are investigated where the atomic chains are formed at the initial stage of nanowire growth. We demonstrate, by calculating the ground-state magnetic configurations, that the exchange coupling, magnetic order, and anisotropies in atomic chains depend sensitively on their chemical composition and adsorption sites on the C u3N network. We find that the exchange interactions in atomic chains could lead to ferromagnetic or antiferromagnetic coupling of atomic spins depending on the position of the chain on the surface. The classical spin dynamics is investigated by means of the kinetic Monte Carlo method based on transition-state theory. Moreover we evaluate the Heisenberg-Dirac-Van Vleck quantum spin Hamiltonian for calculations of the magnetic susceptibility, in order to demonstrate the existence of quantum entanglement in the antiferromagnetic atomic chains at low temperatures.

  7. Interactivity: A Forgotten Art?

    ERIC Educational Resources Information Center

    Sims, Rod

    1997-01-01

    This paper promotes further discussion and analysis of interactivity in learning environments and contains a classification of interaction types appropriate for consideration in multimedia settings. Through an examination of related factors associated with navigation and control, a matrix of interactive dimensions is proposed. (Author)

  8. Global Interaction in Design

    ERIC Educational Resources Information Center

    Bennett, Audrey Grace

    2010-01-01

    Based on a virtual conference, Glide'08 (Global Interaction in Design Education), that brought international design scholars together online, this special issue expands on the topics of cross-cultural communication and design and the technological affordances that support such interaction. The author discusses the need for global interaction in…

  9. Dynamic Interactive Learning Systems

    ERIC Educational Resources Information Center

    Sabry, Khaled; Barker, Jeff

    2009-01-01

    This paper reviews and discusses the notions of interactivity and dynamicity of learning systems in relation to information technologies and design principles that can contribute to interactive and dynamic learning. It explores the concept of dynamic interactive learning systems based on the emerging generation of information as part of a…

  10. Ordinary Social Interaction and the Main Effect Between Perceived Support and Affect.

    PubMed

    Lakey, Brian; Vander Molen, Randy J; Fles, Elizabeth; Andrews, Justin

    2016-10-01

    Relational regulation theory hypothesizes that (a) the main effect between perceived support and mental health primarily reflects ordinary social interaction rather than conversations about stress and how to cope with it, and (b) the extent to which a provider regulates a recipient's mental health primarily reflects the recipient's personal taste (i.e., is relational), rather than the provider's objective supportiveness. In three round-robin studies, participants rated each other on supportiveness and the quality of ordinary social interaction, as well as their own affect when interacting with each other. Samples included marines about to deploy to Afghanistan (N = 100; 150 dyads), students sharing apartments (N = 64; 96 dyads), and strangers (N = 48; 72 dyads). Perceived support and ordinary social interaction were primarily relational, and most of perceived support's main effect on positive affect was redundant with ordinary social interaction. The main effect between perceived support and affect emerged among strangers after brief text conversations, and these links were partially verified by independent observers. Findings for negative affect were less consistent with theory. Ordinary social interaction appears to be able to explain much of the main effect between perceived support and positive affect.

  11. Evolving synergetic interactions

    PubMed Central

    Wu, Bin; Arranz, Jordi; Du, Jinming; Zhou, Da; Traulsen, Arne

    2016-01-01

    Cooperators forgo their own interests to benefit others. This reduces their fitness and thus cooperators are not likely to spread based on natural selection. Nonetheless, cooperation is widespread on every level of biological organization ranging from bacterial communities to human society. Mathematical models can help to explain under which circumstances cooperation evolves. Evolutionary game theory is a powerful mathematical tool to depict the interactions between cooperators and defectors. Classical models typically involve either pairwise interactions between individuals or a linear superposition of these interactions. For interactions within groups, however, synergetic effects may arise: their outcome is not just the sum of its parts. This is because the payoffs via a single group interaction can be different from the sum of any collection of two-player interactions. Assuming that all interactions start from pairs, how can such synergetic multiplayer games emerge from simpler pairwise interactions? Here, we present a mathematical model that captures the transition from pairwise interactions to synergetic multiplayer ones. We assume that different social groups have different breaking rates. We show that non-uniform breaking rates do foster the emergence of synergy, even though individuals always interact in pairs. Our work sheds new light on the mechanisms underlying such synergetic interactions. PMID:27466437

  12. Neutrophil Interactions Stimulate Evasive Hyphal Branching by Aspergillus fumigatus

    PubMed Central

    Jorgensen, Julianne; Frydman, Galit H.; Jones, Caroline N.

    2017-01-01

    Invasive aspergillosis (IA), primarily caused by Aspergillus fumigatus, is an opportunistic fungal infection predominantly affecting immunocompromised and neutropenic patients that is difficult to treat and results in high mortality. Investigations of neutrophil-hypha interaction in vitro and in animal models of IA are limited by lack of temporal and spatial control over interactions. This study presents a new approach for studying neutrophil-hypha interaction at single cell resolution over time, which revealed an evasive fungal behavior triggered by interaction with neutrophils: Interacting hyphae performed de novo tip formation to generate new hyphal branches, allowing the fungi to avoid the interaction point and continue invasive growth. Induction of this mechanism was independent of neutrophil NADPH oxidase activity and neutrophil extracellular trap (NET) formation, but could be phenocopied by iron chelation and mechanical or physiological stalling of hyphal tip extension. The consequence of branch induction upon interaction outcome depends on the number and activity of neutrophils available: In the presence of sufficient neutrophils branching makes hyphae more vulnerable to destruction, while in the presence of limited neutrophils the interaction increases the number of hyphal tips, potentially making the infection more aggressive. This has direct implications for infections in neutrophil-deficient patients and opens new avenues for treatments targeting fungal branching. PMID:28076396

  13. Reviewing and visualizing the interactions of natural hazards

    NASA Astrophysics Data System (ADS)

    Gill, Joel C.; Malamud, Bruce D.

    2014-12-01

    This paper presents a broad overview, characterization, and visualization of the interaction relationships between 21 natural hazards, drawn from six hazard groups (geophysical, hydrological, shallow Earth, atmospheric, biophysical, and space hazards). A synthesis is presented of the identified interaction relationships between these hazards, using an accessible visual format particularly suited to end users. Interactions considered are primarily those where a primary hazard triggers or increases the probability of secondary hazards occurring. In this paper we do the following: (i) identify, through a wide-ranging review of grey- and peer-review literature, 90 interactions; (ii) subdivide the interactions into three levels, based on how well we can characterize secondary hazards, given information about the primary hazard; (iii) determine the spatial overlap and temporal likelihood of the triggering relationships occurring; and (iv) examine the relationship between primary and secondary hazard intensities for each identified hazard interaction and group these into five possible categories. In this study we have synthesized, using accessible visualization techniques, large amounts of information drawn from many scientific disciplines. We outline the importance of constraining hazard interactions and reinforce the importance of a holistic (or multihazard) approach to natural hazard assessment. This approach allows those undertaking research into single hazards to place their work within the context of other hazards. It also communicates important aspects of hazard interactions, facilitating an effective analysis by those working on reducing and managing disaster risk within both the policy and practitioner communities.

  14. The Interactive Learning Toolkit: supporting interactive classrooms

    NASA Astrophysics Data System (ADS)

    Dutta, S.; McCauley, V.; Mazur, E.

    2004-05-01

    Research-based interactive learning techniques have dramatically improved student understanding. We have created the 'Interactive Learning Toolkit' (ILT), a web-based learning management system, to help implement two such pedagogies: Just in Time Teaching and Peer Instruction. Our main goal in developing this toolkit is to save the instructor time and effort and to use technology to facilitate the interaction between the students and the instructor (and between students themselves). After a brief review of both pedagogies, we will demonstrate the many exciting new features of the ILT. We will show how technology can not only implement, but also supplement and improve these pedagogies. We would like acknowdge grants from NSF and DEAS, Harvard University

  15. Characterization of the proteasome interaction network using a QTAX-based tag-team strategy and protein interaction network analysis.

    PubMed

    Guerrero, Cortnie; Milenkovic, Tijana; Przulj, Natasa; Kaiser, Peter; Huang, Lan

    2008-09-09

    Quantitative analysis of tandem-affinity purified cross-linked (x) protein complexes (QTAX) is a powerful technique for the identification of protein interactions, including weak and/or transient components. Here, we apply a QTAX-based tag-team mass spectrometry strategy coupled with protein network analysis to acquire a comprehensive and detailed assessment of the protein interaction network of the yeast 26S proteasome. We have determined that the proteasome network is composed of at least 471 proteins, significantly more than the total number of proteins identified by previous reports using proteasome subunits as baits. Validation of the selected proteasome-interacting proteins by reverse copurification and immunoblotting experiments with and without cross-linking, further demonstrates the power of the QTAX strategy for capturing protein interactions of all natures. In addition, >80% of the identified interactions have been confirmed by existing data using protein network analysis. Moreover, evidence obtained through network analysis links the proteasome to protein complexes associated with diverse cellular functions. This work presents the most complete analysis of the proteasome interaction network to date, providing an inclusive set of physical interaction data consistent with physiological roles for the proteasome that have been suggested primarily through genetic analyses. Moreover, the methodology described here is a general proteomic tool for the comprehensive study of protein interaction networks.

  16. [Drug-drug interactions: interactions between xenobiotics].

    PubMed

    Haen, E

    2014-04-01

    Drug-drug interactions (DDI) are a major topic in programs for continuous medical education (CME). Many physicians are afraid of being trapped into charges of malpractice; however, DDI cannot be avoided in many cases. They belong to routine medical practice and it is often impossible to avoid them. Moreover, they do not just occur between drugs but between any kind of foreign substance (xenobiotica), such as food (e.g. grapefruit juice, broccoli, barbecue) as well as legal (e.g. tobacco smoke, caffeine and alcohol) and illegal drugs. Therefore, the medical challenge is not just to avoid any interaction. Instead the physician faces the question of how to proceed with drug treatment in the presence of such interactions. Based on the medical education a physician has to judge first of all whether there is a risk for interactions in the prescription being planned for an individual patient. The classification of interactions proposed in this article (PD1-PD4, PK1-PK3) might help as a sort of check list. For more detailed information the physician can then consult one of the many databases available on the internet, such as PSIAConline (http://www.psiac.de) and MediQ (http://www.mediq.ch). Pharmacokinetic interactions can be easily assessed, monitored and controlled by therapeutic drug monitoring (TDM). Besides these tools it is important to keep in mind that nobody knows everything; even physicians do not know everything. So take pride in asking someone who might help and for this purpose AGATE offers a drug information service AID (http://www.amuep-agate.de). Just good for nothing, without being based on any kind of medical approach are computer programs that judge prescriptions without taking into account a patient's individual peculiarities. In case these types of programs produce red exclamation marks or traffic lights to underline their judgment, they might even work in a contrapuntal way by just eliciting insecurity and fear.

  17. The interactive brain hypothesis

    PubMed Central

    Di Paolo, Ezequiel; De Jaegher, Hanne

    2012-01-01

    Enactive approaches foreground the role of interpersonal interaction in explanations of social understanding. This motivates, in combination with a recent interest in neuroscientific studies involving actual interactions, the question of how interactive processes relate to neural mechanisms involved in social understanding. We introduce the Interactive Brain Hypothesis (IBH) in order to help map the spectrum of possible relations between social interaction and neural processes. The hypothesis states that interactive experience and skills play enabling roles in both the development and current function of social brain mechanisms, even in cases where social understanding happens in the absence of immediate interaction. We examine the plausibility of this hypothesis against developmental and neurobiological evidence and contrast it with the widespread assumption that mindreading is crucial to all social cognition. We describe the elements of social interaction that bear most directly on this hypothesis and discuss the empirical possibilities open to social neuroscience. We propose that the link between coordination dynamics and social understanding can be best grasped by studying transitions between states of coordination. These transitions form part of the self-organization of interaction processes that characterize the dynamics of social engagement. The patterns and synergies of this self-organization help explain how individuals understand each other. Various possibilities for role-taking emerge during interaction, determining a spectrum of participation. This view contrasts sharply with the observational stance that has guided research in social neuroscience until recently. We also introduce the concept of readiness to interact to describe the practices and dispositions that are summoned in situations of social significance (even if not interactive). This latter idea links interactive factors to more classical observational scenarios. PMID:22701412

  18. Atom interferometer gyroscope with spin-dependent phase shifts induced by light near a tune-out wavelength.

    PubMed

    Trubko, Raisa; Greenberg, James; Germaine, Michael T St; Gregoire, Maxwell D; Holmgren, William F; Hromada, Ivan; Cronin, Alexander D

    2015-04-10

    Tune-out wavelengths measured with an atom interferometer are sensitive to laboratory rotation rates because of the Sagnac effect, vector polarizability, and dispersion compensation. We observed shifts in measured tune-out wavelengths as large as 213 pm with a potassium atom beam interferometer, and we explore how these shifts can be used for an atom interferometer gyroscope.

  19. Spin-dependent Drell-Yan in QCD to O( αs2) (I). The non-singlet sector

    NASA Astrophysics Data System (ADS)

    Chang, Sanghyeon; Corianò, Claudio; Field, R. D.; Gordon, L. E.

    1998-02-01

    A study of the order αs2 corrections to the Drell-Yan ( non-singler) differential cross section for incoming states of arbitrary longitudinal helicities is presented. The transverse momentum distributions, qT, of the lepton pair are studied and the calculations of Ellis, Martinelli, and Petronzio (EMP) are extended to include polarized initial states. We use the overlineMS scheme and the 't Hooft-Veltman regularization for the helicity projectors. From our results one can obtain the bulk of the totally inclusive NNLO cross section for the production of a Drell-Yan pair in the non-singlet sector by a simple integration over the virtual photon momentum. We show that in the overlineMS scheme helicity is not conserved along the quark lines, unless a finite renormalization is done and one adapts the physical ( overlineMSp) scheme. This aspect of the calculation is similar to the O( αs2) polarized production of single and double photons. Our spin-averaged unpolarized differential cross sections agree with the EMP calculations.

  20. Role of Spin-Dependent Terms in the Relationship among Nuclear Spin-Rotation and NMR Magnetic Shielding Tensors.

    PubMed

    Aucar, I Agustín; Gomez, Sergio S; Giribet, Claudia G; Aucar, Gustavo A

    2016-12-15

    The broadly accepted procedure to obtain the experimental absolute scale of NMR magnetic shieldings, σ, is well-known for nonheavy atom-containing molecules. It was uncovered more than 40 years ago by the works of Ramsey and Flygare. They found a quite accurate relationship among σ and the nuclear spin-rotation constants. Its relativistic extension was very recently proposed, although it has an intrinsic weakness because a new SO-S two-component term needs to be considered. We show how to overcome this problem. We found that (νY(S) - νY(atom,S)) generalizes the SO-S term, where νY(S) = ⟨⟨[((r - rY) × α)/(|r - rY|(3))]; S((4))⟩⟩, r - rY is the electron position with respect to the position of nucleus Y, and S((4)) is the four-component total electron spin. When including this new term, one finds that the best of our relativistic Flygare-like models fits quite well with the results of the most accurate method available at the moment. We also show that the difference among the parallel component of σ(Xe) in XeF2 and σ(Xe) of the free atom is almost completely described by that new term.

  1. Integral equation for spin dependent unintegrated parton distributions incorporating double ln2(1/x) effects at low x

    NASA Astrophysics Data System (ADS)

    Kwieciński, Jan; Maul, Martin

    2003-02-01

    In this paper we derive an integral equation for the evolution of unintegrated (longitudinally) polarized quark and gluon parton distributions. The conventional Catani-Ciafaloni-Fiorani-Marchesini (CCFM) framework is modified at small x in order to incorporate the QCD expectations concerning the double ln2(1/x) resummation at low x for the integrated distributions. Complete Altarelli-Parisi splitting functions are included that makes the formalism compatible with the leading order Altarelli-Parisi evolution at large and moderately small values of x. The obtained modified polarized CCFM equation is shown to be partially diagonalized by the Fourier-Bessel transformation. Results of the numerical solution for this modifed polarized CCFM equation for the nonsinglet quark distributions are presented.

  2. Interface defects in SiC power MOSFETs - An electrically detected magnetic resonance study based on spin dependent recombination

    SciTech Connect

    Gruber, Gernot; Hadley, Peter; Koch, Markus; Peters, Dethard; Aichinger, Thomas

    2014-02-21

    This study presents electrically detected magnetic resonance (EDMR) measurements on a silicon carbide (SiC) MOSFET having the structure of a double-diffused silicon MOSFET (DMOS). The resonance pattern of a SiC DMOS was measured by monitoring the change of the recombination current between the source/body and the drain. The amplitude of the response has a maximum when the device is biased in depletion due to the equal concentrations of electrons and holes at the interface resulting in the most efficient recombination. The measured anisotropic g-tensor has axial symmetry with g{sub ∥} = 2.0051(4) (B ‖ c-axis), and g{sub ⊥} = 2.0029(4) (B⊥ c-axis) and the pattern shows several hyperfine (HF) peaks. We tentatively identify the observed defect as a silicon vacancy located directly at the interface.

  3. Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region

    SciTech Connect

    Xiaochao Zheng; Konrad Aniol; David Armstrong; Todd Averett; William Bertozzi; Sebastien Binet; Etienne Burtin; Emmanuel Busato; Cornel Butuceanu; John Calarco; Alexandre Camsonne; Gordon Cates; Zhengwei Chai; Jian-ping Chen; Seonho Choi; Eugene Chudakov; Francesco Cusanno; Raffaele De Leo; Alexandre Deur; Sonja Dieterich; Dipangkar Dutta; John Finn; Salvatore Frullani; Haiyan Gao; Juncai Gao; Franco Garibaldi; Shalev Gilad; Ronald Gilman; Javier Gomez; Jens-ole Hansen; Douglas Higinbotham; Wendy Hinton; Tanja Horn; Cornelis De Jager; Xiaodong Jiang; Lisa Kaufman; James Kelly; Wolfgang Korsch; Kevin Kramer; John Lerose; David Lhuillier; Nilanga Liyanage; Demetrius Margaziotis; Frederic Marie; Pete Markowitz; Kathy Mccormick; Zein-eddine Meziani; Robert Michaels; Bryan Moffit; Sirish Nanda; Damien Neyret; Sarah Phillips; Anthony Powell; Thierry Pussieux; Bodo Reitz; Julie Roche; Michael Roedelbronn; Guy Ron; Marat Rvachev; Arunava Saha; Nikolai Savvinov; Jaideep Singh; Simon Sirca; Karl Slifer; Patricia Solvignon; Paul Souder; Daniel Steiner; Steffen Strauch; Vincent Sulkosky; William Tobias; Guido Urciuoli; Antonin Vacheret; Bogdan Wojtsekhowski; Hong Xiang; Yuan Xiao; Feng Xiong; Bin Zhang; Lingyan Zhu; Xiaofeng Zhu; Piotr Zolnierczuk

    2004-05-01

    We report on measurements of the neutron spin asymmetries A{sub 1,2}{sup n} and polarized structure functions g{sub 1,2}{sup n} at three kinematics in the deep inelastic region, with x = 0.33, 0.47 and .60 and Q{sub 2} = 2.7, 3.5 and 4.8 (GeV/c){sup 2}, respectively. These measurements were performed using a 5.7 GeV longitudinally-polarized electron beam and a polarized {sup 3}He target. The results for A{sub 1}{sup n} and g{sub 1}{sup n} at x = 0.33 are consistent with previous world data and, at the two higher x points, have improved the precision of the world data by about an order of magnitude. The new A{sub 1}{sup n} data show a zero crossing around x = 0.47 and the value at x = 0.60 is significantly positive. These results agree with a next-to-leading order QCD analysis of previous world data. The trend of data at high x agrees with constituent quark model predictions but disagrees with that from leading-order perturbative QCD (pQCD) assuming hadron helicity conservation. Results for A{sub 2}{sup n} and g{sub 2}{sup n} have a precision comparable to the best world data in this kinematic region. Combined with previous world data, the moment d{sub 2}{sup n} was evaluated and the new result has improved the precision of this quantity by about a factor of two. When combined with the world proton data, polarized quark distribution functions were extracted from the new g{sub 1}{sup n}/F{sub 1}{sup n} values based on the quark parton model. While results for {Delta}u/u agree well with predictions from various models, results for {Delta}d/d disagree with the leading-order pQCD prediction when hadron helicity conservation is imposed.

  4. Intrinsic spin dependent and ferromagnetic stability on edge saturated zigzag graphene-like carbon-nitride nanoribbons

    SciTech Connect

    Zhang, Shuai; Li, Chong E-mail: jiayu@zzu.edu.cn; Li, S. F.; Sun, Q.; Jia, Yu E-mail: jiayu@zzu.edu.cn; Guo, Z. X.

    2014-04-28

    Using first-principles calculations, we have investigated the electronic and magnetic properties of zigzag graphene-like carbon-nitride nanoribbons (Zg-CNNRs) with mono- and dihydrogen-terminated edges asymmetrically. The results demonstrate that spin-down channel completely dominates the states adjacent Fermi level, which is an intrinsic feature and can be accounted for the valence band maximum derived from the nonbonding N-(p{sub x},p{sub y}) orbitals, instead of the bonding C/N-p{sub z} π state. Importantly, ferromagnetic ordering is found to be preferred and the magnetism is entirely localized on the N sites of saturated edge due to its stronger electronegativity. Additionally, various edge saturations are further proposed to try to enhance the ferromagnetic ordering and to manipulate the magnetism distributions of Zg-CNNRs.

  5. Primarily Writing: A Practical Guide for Teachers of Young Children.

    ERIC Educational Resources Information Center

    Rickards, Debbie; Hawes, Shirl

    Intended for primary teachers, this resource guide provides explanations of the theory underlying successful writing workshops, plus practical help for putting the ideas to work. With the guide, teachers can see how to implement writing workshop; how to recognize and teach target skills such as organization and revision; and how to enhance writing…

  6. Broad Considerations Concerning Electrochemical Electrodes in Primarily Fluid Environments

    PubMed Central

    Jesudason, Christopher G.

    2009-01-01

    This review is variously a presentation, reflection, synthesis and report with reference to more recent developments of an article – in a journal which has ceased publication – entitled “Some Electrode Theorems with Experimental Corroboration, Inclusive of the Ag/AgCl System” Internet Journal of Chemistry, (http://www.ijc.com), Special Issues: Vol. 2 Article 24 (1999). The results from new lemmas relating charge densities and capacitance in a metallic electrode in equilibrium with an ionic solution are used to explain the data and observed effects due to Esin, Markov, Grahame, Lang and Kohn. Size effects that vary the measured e.m.f. of electrodes due to changes in the electronic chemical potential are demonstrated in experiment and theory implying the need for standardization of electrodes with respect to geometry and size. The widely used Stern modification of the Gouy-Chapman theory is shown to be mostly inapplicable for many of the problems where it is employed. Practical consequences of the current development include the possibility of determining the elusive single-ion activity coefficients of solution ions directly from the expression given by a simplified capacitance theorem, the potential of zero charge and the determination of single ion concentrations of active species in the electrode reactions from cell e.m.f. measurements. PMID:19564949

  7. What Happens to Marriages Built Primarily on Sex?

    ERIC Educational Resources Information Center

    Mace, David R.

    1971-01-01

    In an interview, a marriage counselor answers questions concerning sex in marriage. He concludes that sex alone is too narrow a base for a marriage to rest upon and for a successful marriage, there is a need for a deeper basis of companionship. (Author/CG)

  8. Photoprotective substance occurs primarily in outer layers of fish skin

    USGS Publications Warehouse

    Fabacher, D.L.; Little, E.E.

    1998-01-01

    Methanol extracts of dorsal skin layers, eyes, gills, and livers from ultraviolet-B (UVB) radiation-sensitive and UVB-tolerant species of freshwater fish were examined for a substance that appears to be photoprotective. Significantly larger amounts of this substance were found in extracts of outer dorsal skin layers from both UVB-sensitive and UVB-tolerant fish when compared with extracts of inner dorsal skin layers. This substance occurred in minor amounts or was not detected in eye, gill, and liver extracts. The apparent primary function of this substance in fish is to protect the cells in outer dorsal skin layers from harmful levels of UVB radiation.

  9. Imaging of genetic and degenerative disorders primarily causing Parkinsonism.

    PubMed

    Brooks, David J

    2016-01-01

    In this chapter the structural and functional imaging changes associated with both genetic causes of Parkinson's disease and the sporadic condition are reviewed. The role of imaging for supporting diagnosis and detecting subclinical disease is discussed and the potential use and drawbacks of using imaging biomarkers for monitoring disease progression are debated. Additionally, the use of imaging for differentiating atypical parkinsonian syndromes from Parkinson's disease is presented.

  10. Moraxella Species Are Primarily Responsible for Generating Malodor in Laundry

    PubMed Central

    Mitani, Asako; Niwano, Yu; Takeuchi, Kohei; Tanaka, Atsushi; Yamaguchi, Noriko; Kawamura, Yoshiaki; Hitomi, Jun

    2012-01-01

    Many people in Japan often detect an unpleasant odor generated from laundry that is hung to dry indoors or when using their already-dried laundry. Such an odor is often described as a “wet-and-dirty-dustcloth-like malodor” or an “acidic or sweaty odor.” In this study, we isolated the major microorganisms associated with such a malodor, the major component of which has been identified as 4-methyl-3-hexenoic acid (4M3H). The isolates were identified as Moraxella osloensis by morphological observation and biochemical and phylogenetic tree analyses. M. osloensis has the potential to generate 4M3H in laundry. The bacterium is known to cause opportunistic infections but has never been known to generate a malodor in clothes. We found that M. osloensis exists at a high frequency in various living environments, particularly in laundry in Japan. The bacterium showed a high tolerance to desiccation and UV light irradiation, providing one of the possible reasons why they survive in laundry during and even after drying. PMID:22367080

  11. Primarily Plants, A Plant Study for K-3. Project AIMS.

    ERIC Educational Resources Information Center

    Hoover, Evalyn; Mercier, Sheryl

    Project AIMS (Activities to Integrate Mathematics and Science) has as its purpose the integration of subject matter in grades K-9. Field testing of the curriculum materials produced by AIMS indicates that this interpretation produces the following beneficial results: (1) mathematics becomes more meaningful, hence more useful; (2) science is…

  12. Emissions of volatile organic compounds (primarily oxygenated species) from pasture

    NASA Astrophysics Data System (ADS)

    Kirstine, Wayne; Galbally, Ian; Ye, Yuerong; Hooper, Martin

    1998-05-01

    The volatile organic compound (VOC) emissions from pasture at a site in southeastern Victoria, Australia, were monitored over a 2 year period using a static chamber technique. Fluxes up to 23,000 μg(C) m-2 h-1 were detected, with the higher fluxes originating from clover rather than from grass species. Gas Chromatographic analyses indicated that emissions from both grass and clover were high in oxygenated hydrocarbons including methanol, ethanol, propanone, butanone, and ethanal, and extremely low in isoprene and monoterpenes. In the case of clover, butanone made up 45-50% of the total emissions. When grass and clover were freshly mown, there were significantly enhanced emissions of VOCs. These enhanced emissions included both those oxygenates emitted from uncut pasture and also C6-oxygenates, including (Z)-3-hexenal, (E)-2-hexenal, (Z)-2-hexen-1-ol, (Z)-3-hexen-l-ol, and (Z)-3-hexenyl acetate. Emissions from the undisturbed pasture increased markedly with temperature and the intensity of solar radiation, peaking at midday and ceasing at night. The fluxes, when normalized to a temperature of 30°C and a light intensity of 1000 μE m-2 s-1 were, for grass and clover respectively, about one eighth and two fifths of the equivalent fluxes reported to occur from U.S. woodlands. The annual integrated emission from the pasture was approximately 1.9 g(C) m-2 or 1.3 mg(C) g-1 (dry matter). The large transient fluxes that occurred following physical damaging of the pasture, when integrated over time, could be of the same order as those emissions that were observed from undisturbed pasture. In the case of methanol, and perhaps ethanol, the emissions from grasslands may be significant global sources of these gases.

  13. [Amyotrophic lateral sclerosis: is the astrocyte the cell primarily involved?].

    PubMed

    Sica, Roberto E

    2013-01-01

    So far, amyotrophic lateral sclerosis (ALS) is thought as due to a primary insult of the motor neurons. None of its pathogenic processes proved to be the cause of the illness, nor can be blamed environmental agents. Motor neurons die by apoptosis, leaving the possibility that their death might be due to an unfriendly environment, unable to sustain their health, rather than being directly targeted themselves. These reasons justify an examination of the astrocytes, because they have the most important role controlling the neurons' environment. It is known that astrocytes are plastic, enslaving their functions to the requirements of the neurons to which they are related. Each population of astrocytes is unique, and if it were affected the consequences would reach the neurons that it normally sustains. In regard to the motor neurons, this situation would lead to a disturbed production and release of astrocytic neurotransmitters and transporters, impairing nutritional and trophic support as well. For explaining the spreading of muscle symptoms in ALS, correlated with the type of spreading observed at the cortical and spinal motor neurons pools, the present hypotheses suggests that the illness-causing process is spreading among astrocytes, through their gap junctions, depriving the motor neurons of their support. Also it is postulated that a normal astrocytic protein becomes misfolded and infectious, inducing the misfolding of its wild type, travelling from one protoplasmatic astrocyte to another and to the fibrous astrocytes encircling the pyramidal pathway which joints the upper and lower motoneurones.

  14. Understanding substituent effects in noncovalent interactions involving aromatic rings.

    PubMed

    Wheeler, Steven E

    2013-04-16

    be enhanced only to the extent provided by each substituent on its own, unless the substituents on opposing rings are in close proximity. Overall, this local, direct interaction model predicts that substituent effects in π-stacking interactions will be additive and transferable and will also depend on the relative position of substituents on opposing rings. For cation/π and anion/π interactions, similar π-resonance-based models pervade the literature. Again, computational results indicate that substituent effects in model ion/π complexes can be described primarily in terms of direct interactions between the ion and the substituent. Changes in the aryl π-system do not significantly affect these interactions. We also present a simple electrostatic model that further demonstrates this effect and suggests that the dominant interaction for simple substituents is the interaction of the charged ion with the local dipole associated with the substituents. Finally, we discuss substituent effects in electrostatic potentials (ESPs), which are widely used in discussions of noncovalent interactions. In the past, widespread misconceptions have confused the relationship between changes in ESPs and local changes in the electron density. We have shown that computed ESP plots of diverse substituted arenes can be reproduced without altering the aryl π-density. This is because substituent-induced changes in the ESP above the center of aryl rings result primarily from through-space effects of substituents rather than through changes in the distribution of the π-electron density.

  15. How Interactive Is the Interactive Whiteboard?

    ERIC Educational Resources Information Center

    Quashie, Valerie

    2009-01-01

    An interactive whiteboard (IWB) is simply a surface onto which a computer screen can be displayed, via a projector. It is touch-sensitive and lets one use a pen like a mouse, controlling the computer from the board itself. Everything that can be displayed on a computer can be displayed onto the whiteboard and, if the computer is linked to speakers…

  16. Food-drug interactions.

    PubMed

    Bushra, Rabia; Aslam, Nousheen; Khan, Arshad Yar

    2011-03-01

    The effect of drug on a person may be different than expected because that drug interacts with another drug the person is taking (drug-drug interaction), food, beverages, dietary supplements the person is consuming (drug-nutrient/food interaction) or another disease the person has (drug-disease interaction). A drug interaction is a situation in which a substance affects the activity of a drug, i.e. the effects are increased or decreased, or they produce a new effect that neither produces on its own. These interactions may occur out of accidental misuse or due to lack of knowledge about the active ingredients involved in the relevant substances. Regarding food-drug interactions physicians and pharmacists recognize that some foods and drugs, when taken simultaneously, can alter the body's ability to utilize a particular food or drug, or cause serious side effects. Clinically significant drug interactions, which pose potential harm to the patient, may result from changes in pharmaceutical, pharmacokinetic, or pharmacodynamic properties. Some may be taken advantage of, to the benefit of patients, but more commonly drug interactions result in adverse drug events. Therefore it is advisable for patients to follow the physician and doctors instructions to obtain maximum benefits with least food-drug interactions. The literature survey was conducted by extracting data from different review and original articles on general or specific drug interactions with food. This review gives information about various interactions between different foods and drugs and will help physicians and pharmacists prescribe drugs cautiously with only suitable food supplement to get maximum benefit for the patient.

  17. Food and Drug Interactions

    PubMed Central

    Choi, Jong Hwan; Ko, Chang Mann

    2017-01-01

    Natural foods and vegetal supplements have recently become increasingly popular for their roles in medicine and as staple foods. This has, however, led to the increased risk of interaction between prescribed drugs and the bioactive ingredients contained in these foods. These interactions range from pharmacokinetic interactions (absorption, distribution, metabolism, and excretion influencing blood levels of drugs) to pharmacodynamic interactions (drug effects). In a quantitative respect, these interactions occur mainly during metabolism. In addition to the systemic metabolism that occurs mainly in the liver, recent studies have focused on the metabolism in the gastrointestinal tract endothelium before absorption. Inhibition of metabolism causes an increase in the blood levels of drugs and could have adverse reactions. The food-drug interactions causing increased blood levels of drugs may have beneficial or detrimental therapeutic effects depending on the intensity and predictability of these interactions. It is therefore important to understand the potential interactions between foods and drugs should and the specific outcomes of such interactions. PMID:28261555

  18. The Science of Interaction

    SciTech Connect

    Pike, William A.; Stasko, John T.; Chang, Remco; O'Connell, Theresa

    2009-09-23

    There is a growing recognition with the visual analytics community that interaction and inquiry are inextricable. It is through the interactive manipulation of a visual interface – the analytic discourse – that knowledge is constructed, tested, refined, and shared. This paper reflects on the interaction challenges raised in the original visual analytics research and development agenda and further explores the relationship between interaction and cognition. It identifies recent exemplars of visual analytics research that have made substantive progress toward the goals of a true science of interaction, which must include theories and testable premises about the most appropriate mechanisms for human-information interaction. Six areas for further work are highlighted as those among the highest priorities for the next five years of visual analytics research: ubiquitous, embodied interaction; capturing user intentionality; knowledge-based interfaces; principles of design and perception; collaboration; and interoperability. Ultimately, the goal of a science of interaction is to support the visual analytics community through the recognition and implementation of best practices in the representation of and interaction with visual displays.

  19. Two interacting Hofstadter butterflies

    SciTech Connect

    Barelli, A.; Bellissard, J.; Jacquod, P.; Shepelyansky, D.L.

    1997-04-01

    The problem of two interacting particles in a quasiperiodic potential is addressed. Using analytical and numerical methods, we explore the spectral properties and eigenstates structure from the weak to the strong interaction case. More precisely, a semiclassical approach based on noncommutative geometry techniques is used to understand the intricate structure of such a spectrum. An interaction induced localization effect is furthermore emphasized. We discuss the application of our results on a two-dimensional model of two particles in a uniform magnetic field with on-site interaction. {copyright} {ital 1997} {ital The American Physical Society}

  20. Gender interactions and success.

    PubMed

    Wiggins, Carla; Peterson, Teri

    2004-01-01

    Does gender by itself, or does gender's interaction with career variables, better explain the difference between women and men's careers in healthcare management? US healthcare managers were surveyed regarding career and personal experiences. Gender was statistically interacted with explanatory variables. Multiple regression with backwards selection systematically removed non-significant variables. All gender interaction variables were non-significant. Much of the literature proposes that work and career factors impact working women differently than working men. We find that while gender alone is a significant predictor of income, it does not significantly interact with other career variables.

  1. Turbulence-radiation interactions in a particle-laden flow

    NASA Astrophysics Data System (ADS)

    Frankel, Ari; Pouransari, Hadi; Iaccarino, Gianluca; Mani, Ali

    2014-11-01

    Turbulent fluctuations in a radiatively participating medium can significantly alter the mean heat transfer characteristics in a manner that current RANS models cannot accurately capture. While turbulence-radiation interaction has been studied extensively in traditional combustion systems, such interactions have not yet been studied in the context of particle-laden flows. This work is motivated by applications in particle-based solar receivers in which external radiation is primarily absorbed by a dispersed phase and conductively exchanged with the carrier fluid. Direct numerical simulations of turbulence with Lagrangian particles subject to a collimated radiation source are performed with a flux-limited diffusion approximation to radiative transfer. The dependence of the turbulence-radiation interaction statistics on the particle Stokes number will be demonstrated. Supported by PSAAP II.

  2. Prediction and Annotation of Plant Protein Interaction Networks

    SciTech Connect

    McDermott, Jason E.; Wang, Jun; Yu, Jun; Wong, Gane Ka-Shu; Samudrala, Ram

    2009-02-01

    Large-scale experimental studies of interactions between components of biological systems have been performed for a variety of eukaryotic organisms. However, there is a dearth of such data for plants. Computational methods for prediction of relationships between proteins, primarily based on comparative genomics, provide a useful systems-level view of cellular functioning and can be used to extend information about other eukaryotes to plants. We have predicted networks for Arabidopsis thaliana, Oryza sativa indica and japonica and several plant pathogens using the Bioverse (http://bioverse.compbio.washington.edu) and show that they are similar to experimentally-derived interaction networks. Predicted interaction networks for plants can be used to provide novel functional annotations and predictions about plant phenotypes and aid in rational engineering of biosynthesis pathways.

  3. Negative Social Interactions and Incident Hypertension Among Older Adults

    PubMed Central

    Sneed, Rodlescia S.; Cohen, Sheldon

    2014-01-01

    Objective To determine if negative social interactions are prospectively associated with hypertension among older adults. Methods This is a secondary analysis of data from the 2006 and 2010 waves of the Health and Retirement Study, a survey of community-dwelling older adults (age >50). Total average negative social interactions were assessed at baseline by averaging the frequency of negative interactions across four domains (partner, children, other family, friends). Blood pressure was measured at both waves. Individuals were considered to have hypertension if they reported use of antihypertensive medications, had measured average resting systolic blood pressure ≥ 140 mmHg, or measured average resting diastolic blood pressure ≥90 mmHg. Analyses excluded those hypertensive at baseline and controlled for demographics, personality, positive social interactions, and baseline health. Results Twenty-nine percent of participants developed hypertension over the four-year follow-up. Each one-unit increase in the total average negative social interaction score was associated with a 38% increased odds of developing hypertension. Sex moderated the association between total average negative social interactions and hypertension, with effects observed among women but not men. The association of total average negative interactions and hypertension in women was attributable primarily to interactions with friends, but also to negative interactions with family and partners. Age also moderated the association between total average negative social interactions and hypertension, with effects observed among those ages 51–64, but not those ages ≥65. Conclusion In this sample of older adults, negative social interactions were associated with increased hypertension risk in women and the youngest older adults. PMID:24884909

  4. Equilibrium Denaturation and Preferential Interactions of an RNA Tetraloop with Urea.

    PubMed

    Miner, Jacob C; García, Angel E

    2017-02-16

    Urea is an important organic cosolute with implications in maintaining osmotic stress in cells and differentially stabilizing ensembles of folded biomolecules. We report an equilibrium study of urea-induced denaturation of a hyperstable RNA tetraloop through unbiased replica exchange molecular dynamics. We find that, in addition to destabilizing the folded state, urea smooths the RNA free energy landscape by destabilizing specific configurations, and forming favorable interactions with RNA nucleobases. A linear concentration-dependence of the free energy (m-value) is observed, in agreement with the results of other RNA hairpins and proteins. Additionally, analysis of the hydrogen-bonding and stacking interactions within RNA primarily show temperature-dependence, while interactions between RNA and urea primarily show concentration-dependence. Our findings provide valuable insight into the effects of urea on RNA folding and describe the thermodynamics of a basic RNA hairpin as a function of solution chemistry.

  5. Gene-gene interactions in gastrointestinal cancer susceptibility

    PubMed Central

    Kang, Changwon; Kang, Suk-Jo

    2016-01-01

    Cancer arises from complex, multi-layer interactions between diverse genetic and environmental factors. Genetic studies have identified multiple loci associated with tumor susceptibility. However, little is known about how germline polymorphisms interact with one another and with somatic mutations within a tumor to mediate acquisition of cancer traits. Here, we survey recent studies showing gene-gene interactions, also known as epistases, affecting genetic susceptibility in colorectal, gastric and esophageal cancers. We also catalog epistasis types and cancer hallmarks with respect to the interacting genes. A total of 22 gene variation pairs displayed all levels of statistical epistasis, including synergistic, redundant, suppressive and co-suppressive interactions. Five genes primarily involved in base excision repair formed a linear topology in the interaction network, MUTYH-OGG1-XRCC1-PARP1-MMP2, and three genes in mTOR cell-proliferation pathway formed another linear network, PRKAG2-RPS6KB1-PIK3CA. Discrete pairwise epistasis was also found in nucleotide excision repair, detoxification, proliferation, TP53, TGF-β and other pathways. We propose that three modes of biological interaction underlie the molecular mechanisms for statistical epistasis. The direct binding, linear pathway and convergence modes can exhibit any level of statistical epistasis in susceptibility to gastrointestinal cancers, and this is likely true for other complex diseases as well. This review highlights the link between cancer hallmarks and susceptibility genes. PMID:27588484

  6. Reconceptualizing sex, brain and psychopathology: interaction, interaction, interaction

    PubMed Central

    Joel, D; Yankelevitch-Yahav, R

    2014-01-01

    In recent years there has been a growing recognition of the influence of sex on brain structure and function, and in relation, on the susceptibility, prevalence and response to treatment of psychiatric disorders. Most theories and descriptions of the effects of sex on the brain are dominated by an analogy to the current interpretation of the effects of sex on the reproductive system, according to which sex is a divergence system that exerts a unitary, overriding and serial effect on the form of other systems. We shortly summarize different lines of evidence that contradict aspects of this analogy. The new view that emerges from these data is of sex as a complex system whose different components interact with one another and with other systems to affect body and brain. The paradigm shift that this understanding calls for is from thinking of sex in terms of sexual dimorphism and sex differences, to thinking of sex in terms of its interactions with other factors and processes. Our review of data obtained from animal models of psychopathology clearly reveals the need for such a paradigmatic shift, because in the field of animal behaviour whether a sex difference exists and its direction depend on the interaction of many factors including, species, strain, age, specific test employed and a multitude of environmental factors. We conclude by explaining how the new conceptualization can account for sex differences in psychopathology. Linked Articles This article is part of a themed section on Animal Models in Psychiatry Research. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-20 PMID:24758640

  7. Drug-nutrient interactions.

    PubMed

    Chan, Lingtak-Neander

    2013-07-01

    Drug-nutrient interactions are defined as physical, chemical, physiologic, or pathophysiologic relationships between a drug and a nutrient. The causes of most clinically significant drug-nutrient interactions are usually multifactorial. Failure to identify and properly manage drug-nutrient interactions can lead to very serious consequences and have a negative impact on patient outcomes. Nevertheless, with thorough review and assessment of the patient's history and treatment regimens and a carefully executed management strategy, adverse events associated with drug-nutrient interactions can be prevented. Based on the physiologic sequence of events after a drug or a nutrient has entered the body and the mechanism of interactions, drug-nutrient interactions can be categorized into 4 main types. Each type of interaction can be managed using similar strategies. The existing data that guide the clinical management of most drug-nutrient interactions are mostly anecdotal experience, uncontrolled observations, and opinions, whereas the science in understanding the mechanism of drug-nutrient interactions remains limited. The challenge for researchers and clinicians is to increase both basic and higher level clinical research in this field to bridge the gap between the science and practice. The research should aim to establish a better understanding of the function, regulation, and substrate specificity of the nutrient-related enzymes and transport proteins present in the gastrointestinal tract, as well as assess how the incidence and management of drug-nutrient interactions can be affected by sex, ethnicity, environmental factors, and genetic polymorphisms. This knowledge can help us develop a true personalized medicine approach in the prevention and management of drug-nutrient interactions.

  8. Visualizing Dispersion Interactions

    ERIC Educational Resources Information Center

    Gottschalk, Elinor; Venkataraman, Bhawani

    2014-01-01

    An animation and accompanying activity has been developed to help students visualize how dispersion interactions arise. The animation uses the gecko's ability to walk on vertical surfaces to illustrate how dispersion interactions play a role in macroscale outcomes. Assessment of student learning reveals that students were able to develop…

  9. University-industry interaction

    NASA Technical Reports Server (NTRS)

    Hastings, Daniel E.

    1990-01-01

    It is posited that university industry interaction is highly desirable from the viewpoint of the long term economic development of the country as well as being desirable for the Space Grant Programs. The present and future possible interactions are reviewed for the three university levels namely, undergraduate, graduate, and faculty research.

  10. Interactive Visualization of Dependencies

    ERIC Educational Resources Information Center

    Moreno, Camilo Arango; Bischof, Walter F.; Hoover, H. James

    2012-01-01

    We present an interactive tool for browsing course requisites as a case study of dependency visualization. This tool uses multiple interactive visualizations to allow the user to explore the dependencies between courses. A usability study revealed that the proposed browser provides significant advantages over traditional methods, in terms of…

  11. Storyboarding Multimedia Interactions.

    ERIC Educational Resources Information Center

    Martin, Linda C.

    2000-01-01

    Understanding how to include interactivity when designing multimedia-based training (MBT) storyboards is a major key for a successful MBT. Discusses the basic formats of interactions and when to use each format. Describes how to storyboard and areas to address, including: the display area, prompts, branching, programming and graphics notes,…

  12. Interactive Presentation of Content

    ERIC Educational Resources Information Center

    Magdin, Martin; Turcáni, Milan; Vrábel, Marek

    2009-01-01

    In the paper we discus about design of universal environment for solution of creating effective multimedia applications with accent on the implementation of interactive elements with the possibility of using the adaptive systems (AS). We also discuss about possibilities of offline presentation of this interactive multimedia adaptive animations…

  13. Interactive TV: The Sequel.

    ERIC Educational Resources Information Center

    Brown, Eric

    1998-01-01

    Examines the future of interactive TV where consumers navigate the Internet on their TVs with WebTV set-top boxes. Focuses on competition between cable companies and computer and consumer electronics companies. Highlights nine companies and partnerships developing interactive hardware and services. (PEN)

  14. Normal Shock Vortex Interaction

    DTIC Science & Technology

    2003-03-01

    Figure 9: Breakdown map for normal-shock vortex-interaction. References [1] O. Thomer, W. Schroder and M. Meinke , Numerical Simulation of Normal...and Oblique-Shock Vortex Interaction, ZAMM Band 80, Sub. 1, pp. 181-184, 2000. [2] O. Thomer, E. Krause, W. Schroder and M. Meinke , Computational

  15. Let Social Interaction Flourish

    ERIC Educational Resources Information Center

    Case, Anny Fritzen

    2016-01-01

    The author describes lessons learned--through a high school project that grouped English language learners with native speakers to create a video--about ways to foster respectful, productive interaction among English learners and peers who are native speakers. The potential benefits of students who are just learning English interacting socially…

  16. Elementary particle interactions

    SciTech Connect

    Bugg, W.M.; Condo, G.T.; Handler, T.; Hart, E.L.; Ward, B.F.L.; Close, F.E.; Christophorou, L.G.

    1990-10-01

    This report discusses freon bubble chamber experiments exposed to {mu}{sup +} and neutrinos, photon-proton interactions; shower counter simulations; SLD detectors at the Stanford Linear Collider, and the detectors at the Superconducting Super Collider; elementary particle interactions; physical properties of dielectric materials used in High Energy Physics detectors; and Nuclear Physics. (LSP)

  17. New experimental possibility to search for the ratio of a possible T-violating amplitude to the weak-interaction amplitude in polarized neutron transmission through a polarized nuclear target

    SciTech Connect

    Lukashevich, V. V.; Aldushchenkov, A. V.; Dallman, D.

    2011-03-15

    This paper considers a spin-dependent neutron interaction with optical potentials (fields) from the strong interaction, the weak interaction, and an assumed T-violating interaction. The vector sum of these fields and their interferences determines an effective field of the target with an angular position in space due to polar and azimuthal angles. The phase of the azimuthal component is found to be the sum of two angles. The tangent of the first angle is equal to the ratio of the T-violating forward-scattering amplitude D to the weak-interaction amplitude C. The quantity is of interest. The tangent of the second angle depends on the spin rotation in the residual pseudomagnetic field of the target, and it can be treated as a background effect. This paper shows that the second angle has different signs in measurements with polarized and unpolarized neutrons; thus, two measurements allow it to be compensated for. In addition, the use of the Ramsey method of separated oscillatory fields for measurement of the neutron spin rotation angle, depending on the phase of the rf field in the Ramsey cell, allows a cosine-like spectrum to be measured. This spectrum is called a phase spectrum. The phase spectra measured with polarized and unpolarized targets have a phase shift. The measurements of this phase shift with polarized and nonpolarized neutrons at a p-wave resonance enable the ratio D/C to be isolated. We also describe the algorithm for separating the ratio D/C, taking into account the influence of the fringing fields of the Ramsey coil magnet and the target magnet.

  18. Spacelab user interaction

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The results of the third and final phase of a study undertaken to define means of optimizing the Spacelab experiment data system by interactively manipulating the flow of data were presented. A number of payload applicable interactive techniques and an integrated interaction system for each of two possible payloads are described. These interaction systems have been functionally defined and are accompanied with block diagrams, hardware specifications, software sizing and speed requirements, operational procedures and cost/benefits analysis data for both onboard and ground based system elements. It is shown that accrued benefits are attributable to a reduction in data processing costs obtained by, generally, a considerable reduction in the quantity of data that might otherwise be generated without interaction. One other additional anticipated benefit includes the increased scientific value obtained by the quicker return of all useful data.

  19. Space shuttle orbiter reaction control system jet interaction study

    NASA Technical Reports Server (NTRS)

    Rausch, J. R.

    1975-01-01

    The space shuttle orbiter has forward mounted and rear mounted Reaction Control Systems (RCS) which are used for orbital maneuvering and also provide control during entry and abort maneuvers in the atmosphere. The effects of interaction between the RCS jets and the flow over the vehicle in the atmosphere are studied. Test data obtained in the NASA Langley Research Center 31 inch continuous flow hypersonic tunnel at a nominal Mach number of 10.3 is analyzed. The data were obtained with a 0.01 scale force model with aft mounted RCS nozzles mounted on the sting off of the force model balance. The plume simulations were accomplished primarily using air in a cold gas simulation through scaled nozzles, however, various cold gas mixtures of Helium and Argon were also tested. The effect of number of nozzles was tested as were limited tests of combined controls. The data show that RCS nozzle exit momentum ratio is the primary correlating parameter for effects where the plume impinges on an adjacent surface and mass flow ratio is the parameter where the plume interaction is primarily with the external stream. An analytic model of aft mounted RCS units was developed in which the total reaction control moments are the sum of thrust, impingement, interaction, and cross-coupling terms.

  20. Venus: Interaction with Solar Wind

    NASA Astrophysics Data System (ADS)

    Russell, C.; Luhmann, J.; Murdin, P.

    2002-07-01

    The solar wind interaction with VENUS provides the archetypal interaction of a flowing magnetized PLASMA with a PLANETARY IONOSPHERE. Mars interacts with the solar wind in much the same way as does Venus, while the rotating plasma in the Saturnian magnetosphere is believed to interact similarly with its moon, Titan (see SATURN: MAGNETOSPHERE INTERACTION WITH TITAN). The interaction of the Jovian ...