WorldWideScience

Sample records for polarization current behavior

  1. High current polarized proton sources

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, J.G.

    1988-01-01

    Polarized proton sources are now being used more frequently on linacs. In pulsed operation up to 10 mA of /rvec H//sup +/ and 0.4 mA of /rvec H//sup /minus// have been produced. The present status of these sources, and developments to reach even higher intensities, are reviewed. 39 refs., 1 tab.

  2. Amplification of spin-current polarization

    Science.gov (United States)

    Saha, D.; Holub, M.; Bhattacharya, P.

    2007-08-01

    A ferromagnet/semiconductor based electrically controlled spin-current amplifier using a dual-drain nonlocal lateral spin valve is demonstrated. The spin polarization injected by the source into the channel is amplified at the second drain contact. An amplified current spin polarization of 100% is measured. The controlled variation of amplifier gain with bias is also demonstrated. The observations are explained in the framework of the spin drift-diffusion model.

  3. Concentration polarization, surface currents, and bulk advection in a microchannel

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder; Bruus, Henrik

    2014-01-01

    We present a comprehensive analysis of salt transport and overlimiting currents in a microchannel during concentration polarization. We have carried out full numerical simulations of the coupled Poisson-Nernst-Planck-Stokes problem governing the transport and rationalized the behavior of the syst...... as in the limit of negligible surface charge. By including the effects of diffusion and advection in the diffuse part of the electric double layers, we extend a recently published analytical model of overlimiting current due to surface conduction....

  4. FDI, Polarized Globalization, and the Current Crisis

    OpenAIRE

    David Mayer-Foulkes

    2012-01-01

    Even though the current crisis is clearly global, much of the analysis and many of the policy proposals have a single country viewpoint, particularly in the case of the United States. Explanations concentrate, for example on the financial system and on population-wide indebtment. Here we examine the polarized impact of globalization on economic growth, which arises from the intense interaction between developed and underdeveloped countries, for example between the United States and China. We ...

  5. Ion Concentration Polarization by Bifurcated Current Path.

    Science.gov (United States)

    Kim, Junsuk; Cho, Inhee; Lee, Hyomin; Kim, Sung Jae

    2017-07-11

    Ion concentration polarization (ICP) is a fundamental electrokinetic process that occurs near a perm-selective membrane under dc bias. Overall process highly depends on the current transportation mechanisms such as electro-convection, surface conduction and diffusioosmosis and the fundamental characteristics can be significantly altered by external parameters, once the permselectivity was fixed. In this work, a new ICP device with a bifurcated current path as for the enhancement of the surface conduction was fabricated using a polymeric nanoporous material. It was protruded to the middle of a microchannel, while the material was exactly aligned at the interface between two microchannels in a conventional ICP device. Rigorous experiments revealed out that the propagation of ICP layer was initiated from the different locations of the protruded membrane according to the dominant current path which was determined by a bulk electrolyte concentration. Since the enhancement of surface conduction maintained the stability of ICP process, a strong electrokinetic flow associated with the amplified electric field inside ICP layer was significantly suppressed over the protruded membrane even at condensed limit. As a practical example of utilizing the protruded device, we successfully demonstrated a non-destructive micro/nanofluidic preconcentrator of fragile cellular species (i.e. red blood cells).

  6. Detecting Spin-Polarized Currents in Ballistic Nanostructures

    DEFF Research Database (Denmark)

    Potok, R.; Folk, J.; M. Marcus, C.

    2002-01-01

    We demonstrate a mesoscopic spin polarizer/analyzer system that allows the spin polarization of current from a quantum point contact in an in-plane magnetic field to be measured. A transverse focusing geometry is used to couple current from an emitter point contact into a collector point contact....

  7. Micromagnetic investigation of the dynamics of magnetization switching induced by a spin polarized current

    Science.gov (United States)

    Lee, Kyung-Jin; Dieny, Bernard

    2006-03-01

    Using micromagnetic modeling, we tested a prediction of single-domain spin-torque theory which switching current density depends only weakly on magnetic cell size. The switching time and current density are strongly affected by the cell size for low spin polarization. Larger samples with a small length-to-width ratio and small spin polarization can exhibit a nonmonotonous dependence of switching time on current. Excitation of incoherent spin waves caused by the circular Oersted field due to the current is responsible for this nonmonotonous dependence. However, the magnetic dynamics recovers a single-domain-like behavior when the spin polarization is high and/or the cell size is small.

  8. Spin-polarized current generated by magneto-electrical gating

    International Nuclear Information System (INIS)

    Ma Minjie; Jalil, Mansoor Bin Abdul; Tan, Seng Ghee

    2012-01-01

    We theoretically study spin-polarized current through a single electron tunneling transistor (SETT), in which a quantum dot (QD) is coupled to non-magnetic source and drain electrodes via tunnel junctions, and gated by a ferromagnetic (FM) electrode. The I–V characteristics of the device are investigated for both spin and charge currents, based on the non-equilibrium Green's function formalism. The FM electrode generates a magnetic field, which causes a Zeeman spin-splitting of the energy levels in the QD. By tuning the size of the Zeeman splitting and the source–drain bias, a fully spin-polarized current is generated. Additionally, by modulating the electrical gate bias, one can effect a complete switch of the polarization of the tunneling current from spin-up to spin-down current, or vice versa. - Highlights: ► The spin polarized transport through a single electron tunneling transistor is systematically studied. ► The study is based on Keldysh non-equilibrium Green's function and equation of motion method. ► A fully spin polarized current is observed. ► We propose to reverse current polarization by the means of gate voltage modulation. ► This device can be used as a bi-polarization current generator.

  9. Control of Domain Wall Polarity by Current Pulses

    Science.gov (United States)

    Vanhaverbeke, A.; Bischof, A.; Allenspach, R.

    2008-09-01

    Direct observation of current-induced propagation of purely transverse magnetic domain walls with spin-polarized scanning electron microscopy is reported in Fe30Ni70 nanowires. After propagation, the domain walls keep their transverse nature but switch polarity in some cases. For uniform Ni70Fe30 wires, the effect is random and illustrates domain-wall propagation above the Walker threshold. In the case of Ni70Fe30/Fe wires, the transverse magnetization component in the wall is entirely determined by the polarity of the current pulse, an effect that is not reconciled by present theories even when taking into account the nonuniform Oersted field generated by the current.

  10. Current density functional theory for optical spectra : A polarization functional

    NARCIS (Netherlands)

    Boeij, P.L. de; Kootstra, F.; Berger, J.A.; Leeuwen, R. van; Snijders, J.G.

    2001-01-01

    In this paper we present a new approach to calculate optical spectra, which for the first time uses a polarization dependent functional within current density functional theory (CDFT), which was proposed by Vignale and Kohn. This polarization dependent functional includes exchange-correlation (xc)

  11. Floating Inductance and FDNR Using Positive Polarity Current Conveyors

    Directory of Open Access Journals (Sweden)

    K. Pal

    2004-01-01

    Full Text Available A generalized circuit based on five positive polarity second-generation current conveyors is introduced. The circuit simulates a floating inductance, capacitor floatation circuit and floating fdnr. All these circuits use grounded capacitors.

  12. The role of polarization current in magnetic island evolution

    International Nuclear Information System (INIS)

    Connor, J.W.; Waelbroeck, F.L.; Wilson, H.R.

    2001-01-01

    The polarization current plays an important role in the evolution of magnetic islands with a width comparable to the characteristic ion orbit width. Understanding the evolution of such small magnetic islands is important for two reasons: (1) to investigate the threshold mechanisms for growth of large-scale islands (e.g., neoclassical tearing modes), and (2) to describe the drive mechanisms for small-scale magnetic turbulence and consequent transport. This article presents a two-fluid, cold ion, collisional analysis of the role of the polarization current in magnetic island evolution in slab geometry. It focuses on the role played by the conjunction of parallel electron dynamics and perpendicular transport (particle diffusion and viscosity) in determining the island rotation frequency and the distribution of the polarization current within the island

  13. Dissolution of Platinum in Hydrochloric Acid Under Industrial-Scale Alternating Current Polarization

    Science.gov (United States)

    Myrzabekov, B. E.; Bayeshov, A. B.; Makhanbetov, A. B.; Mishra, B.; Baigenzhenov, O. S.

    2018-02-01

    The electrochemical behavior of platinum in a hydrochloric acid solution under polarization by an industrial-scale alternating current has been investigated. For the electrical dissolution of platinum, titanium is used as an auxiliary electrode, which increases the yield of platinum dissolution by 12.5 pct. The influence of the concentration of hydrochloric acid, the current densities of the platinum and titanium electrodes, and the temperature of the electrolyte on the efficiency of the process of dissolving platinum have all been studied.

  14. Influence of collision frequency on neoclassical polarization current

    Energy Technology Data Exchange (ETDEWEB)

    Imada, K; Wilson, H R, E-mail: ki504@york.ac.u [Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)

    2009-10-15

    A kinetic theory for the evolution of magnetic islands is considered in a tokamak plasma, in both the low (nu{sub i} << epsilonomega) and high (nu{sub i} >> epsilonomega) collision frequency limits (nu{sub i} is the ion collision frequency, epsilon is the inverse aspect ratio and omega is the island propagation frequency in the E x B rest frame). The calculation of the bootstrap current perturbation in the presence of a magnetic island is reviewed, and is confirmed to be independent of omega and the collision frequency regime. The neoclassical polarization current perturbation is calculated in the two collision frequency limits (within the banana regime). The result in the collisional limit is in agreement with a fluid theory. The effect of collisions in the 'dissipation layer' at the trapped/passing boundary is also considered, for nu{sub i} << epsilonomega. It is found that the dissipation layer provides an additional contribution to the neoclassical polarization current perturbation. Consequently, if the polarization current is stabilizing, it provides a critical island width for instability, which is found to scale as [1+rsq rootnu{sub i}/epsilonomega]{sup 1/2}, where r is a weak logarithmic function of sq rootnu{sub i}/epsilonomega.

  15. Fourier analysis of polar cap electric field and current distributions

    Science.gov (United States)

    Barbosa, D. D.

    1984-01-01

    A theoretical study of high-latitude electric fields and currents, using analytic Fourier analysis methods, is conducted. A two-dimensional planar model of the ionosphere with an enhanced conductivity auroral belt and field-aligned currents at the edges is employed. Two separate topics are treated. A field-aligned current element near the cusp region of the polar cap is included to investigate the modifications to the convection pattern by the east-west component of the interplanetary magnetic field. It is shown that a sizable one-cell structure is induced near the cusp which diverts equipotential contours to the dawnside or duskside, depending on the sign of the cusp current. This produces characteristic dawn-dusk asymmetries to the electric field that have been previously observed over the polar cap. The second topic is concerned with the electric field configuration obtained in the limit of perfect shielding, where the field is totally excluded equatorward of the auroral oval. When realistic field-aligned current distributions are used, the result is to produce severely distorted, crescent-shaped equipotential contours over the cap. Exact, analytic formulae applicable to this case are also provided.

  16. H- ion current from a polarized vapor target

    International Nuclear Information System (INIS)

    Cornelius, W.D.

    1984-01-01

    A method of determining the polarization transferred to hydrogen atoms in charge-exchange reactions is outlined. The method also provides a means of determining target polarizations once the polarization transfer function is known

  17. Electrochemical behavior of uranyl in anhydrous polar organic media

    Energy Technology Data Exchange (ETDEWEB)

    Burn, Adam G.; Nash, Kenneth L. [Washington State Univ., Pullmann, WA (United States). Dept. of Chemistry

    2017-09-01

    Weak complexes between pentavalent and hexavalent actinyl cations have been reported to exist in acidic, non-complexing high ionic strength aqueous media. Such ''cation-cation complexes'' were first identified in the context of actinide-actinide redox reactions in acidic aqueous media relevant to solvent extraction-based separation systems, hence their characterization is of potential interest for advanced nuclear fuel reprocessing. This chemistry could be relevant to efforts to develop advanced actinide separations based on the upper oxidation states of americium, which are of current interest. In the present study, the chemical behavior of pentavalent uranyl was examined in non-aqueous, aprotic polar organic solvents (propylene carbonate and acetonitrile) to determine whether UO{sub 2}{sup +} cations generated at the reducing working electrode surface would interact with the UO{sub 2}{sup 2+} cations in the bulk phase to form cation-cation complexes in such media. In magnesium perchlorate media, the electrolyte adsorbed onto the working electrode surface and interfered with the uranyl reduction/diffusion process through an ECE (electron transfer/chemical reaction/electron transfer) mechanism. In parallel studies of uranyl redox behavior in tetrabutylammonium hexafluorophosphate solutions, an EC (electron transfer/chemical reaction) mechanism was observed in the cyclic voltammograms. Ultimately, no conclusive electrochemical evidence demonstrated uranyl cation-cation interactions in the non-aqueous, aprotic polar organic solvent solutions, though the results reported do not completely rule out the presence of UO{sub 2}{sup +}.UO{sub 2}{sup 2+} complexes.

  18. Magnetospheric convection and current system in the dayside polar cap

    International Nuclear Information System (INIS)

    Nishida, A.; Mukai, T.; Tsuruda, K.; Hayakawa, H.

    1992-01-01

    Field and particle observations on EXOS-D (Akebono) have yielded new information on convection and current system in the dayside polar cap. Convection patterns are distinctly different depending upon whether IMF B z is northward or southward. The number of convection cells is two when B z is southward but four when B z is northward. Lobe cells in which plasma flows sunward in the region of open field lines are observed as a pair (of which one is in the dawn and the other in the dusk sector) for any polarity of IMF B y and B z . Ions in the keV range precipitate not only in the dayside cusp region but also along the sunward directed streamlines of the dawn and dusk lobe cells. These observations require reconsideration on the position and the extent of the reconnection region on the magnetopause. They also suggest that the magnetotail plays a vital role in some phenomena which have been ascribed to dayside magnetopause processes. We have not been able to find evidence to prove the presence of the viscous cell under southward IMF

  19. Simulated warm polar currents during the middle Permian

    Energy Technology Data Exchange (ETDEWEB)

    Winguth, A.M.E.; Kutzbach, J.E. [Wisconsin Univ., Madison, WI (USA). Center for Climatic Research; Heinze, C.; Maier-Reimer, E.; Mikolajewicz, U. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Rowley, D.; Rees, A.; Ziegler, A.M. [Chicago Univ., IL (United States). Dept. of Geophysical Sciences

    2001-05-01

    During Permian Stage 6 (Wordian, Kazanian) the Pangaean supercontinent was surrounded by a superocean - Panthalassa. An ocean general circulation model has been coupled to an atmospheric energy balance model to simulate the sensitivity of the Wordian climate ({proportional_to}265 million years ago) to changes in greenhouse gas concentrations, high latitude geography, and Earth orbital configurations. The model shows a high sensitivity of the ocean circulation to changes in the greenhouse gas forcing, ranging from a forceful southern circulation at low CO{sub 2} concentration (present level) to a more symmetric circulation cell with deep water formation in both hemispheres at high CO{sub 2} concentration (8 x present level). The simulated climate with 4 x present level CO{sub 2} concentration agrees generally well with climate-sensitive sediments and phytogeographic patterns. In this experiment, the model simulates strong subtropical gyres with similarities to the modern South Pacific circulation and moderate surface temperatures on the southern continent Gondwana, resulting from a strong poleward heat transport in the ocean. An even more moderate climate can be generated if high latitude land is removed so that ocean currents can penetrate into the polar regions or if orbital configurations favor high summer insolation over Gondwana. (orig.)

  20. Concentration polarization: Electrodeposition and transport phenomena at overlimiting current

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder

    . Secondly, we investigate concentration polarization in a microchannel with charged walls. We provide full numerical solutions to the transport problem, including the effects of advection and surface conduction in the electric double layers. We show that in large areas of the relevant parameter space...... the transport can be understood in terms of a group of simple analytical models. Some of these are generalizations of a previously published analytical model. In addition to the full numerical model, we employ a numerical boundary layer model with a slip velocity. By carefully comparing the full model...... and the boundary layer model, we reveal a number of issues, which invalidate most previous attempts at modeling microchannel concentration polarization using a slip model. Returning to concentration polarization in a bulk system, we study the effects of water splitting at a permselective membrane. We investigate...

  1. Polarized parton distributions from charged-current deep-inelastic scattering and future neutrino factories

    CERN Document Server

    Forte, Stefano; Ridolfi, G; Forte, Stefano; Mangano, Michelangelo L.; Ridolfi, Giovanni

    2001-01-01

    We discuss the determination of polarized parton distributions from charged-current deep-inelastic scattering experiments. We summarize the next-to-leading order treatment of charged-current polarized structure functions, their relation to polarized parton distributions and scale dependence, and discuss their description by means of a next-to-leading order evolution code. We discuss current theoretical expectations and positivity constraints on the unmeasured C-odd combinations Delta q-Delta qbar of polarized quark distributions, and their determination in charged-current deep-inelastic scattering experiments. We give estimates of the expected errors on charged-current structure functions at a future neutrino factory, and perform a study of the accuracy in the determination of polarized parton distributions that would be possible at such a facility. We show that these measurements have the potential to distinguish between different theoretical scenarios for the proton spin structure.

  2. Polarized parton distributions from charged-current deep-inelastic scattering and future neutrino factories

    International Nuclear Information System (INIS)

    Forte, Stefano; Mangano, Michelangelo L.; Ridolfi, Giovanni

    2001-01-01

    We discuss the determination of polarized parton distributions from charged-current deep-inelastic scattering experiments. We summarize the next-to-leading-order treatment of charged-current polarized structure functions, their relation to polarized parton distributions and scale dependence, and discuss their description by means of a next-to-leading-order evolution code. We discuss current theoretical expectations and positivity constraints on the unmeasured C-odd combinations Δq-Δq-bar of polarized quark distributions, and their determination in charged-current deep-inelastic scattering experiments. We give estimates of the expected errors on charged-current structure functions at a future neutrino factory, and perform a study of the accuracy in the determination of polarized parton distributions that would be possible at such a facility. We show that these measurements have the potential to distinguish between different theoretical scenarios for the proton spin structure

  3. New materials research for high spin polarized current

    International Nuclear Information System (INIS)

    Tezuka, Nobuki

    2012-01-01

    The author reports here a thorough investigation of structural and magnetic properties of Co 2 FeAl 0.5 Si 0.5 Heusler alloy films, and the tunnel magnetoresistance effect for junctions with Co 2 FeAl 0.5 Si 0.5 electrodes, spin injection into GaAs semiconductor from Co 2 FeAl 0.5 Si 0.5 , and spin filtering phenomena for junctions with CoFe 2 O 4 ferrite barrier. It was observed that tunnel magnetoresistance ratio up to 832%(386%) at 9 K (room temperature), which corresponds to the tunnel spin polarization of 0.90 (0.81) for the junctions using Co 2 FeAl 0.5 Si 0.5 Heusler electrodes by optimizing the fabrication condition. It was also found that the tunnel magnetoresistance ratio are almost the same between the junctions with Co 2 FeAl 0.5 Si 0.5 Heusler electrodes on Cr buffered (1 0 0) and (1 1 0) MgO substrates, which indicates that tunnel spin polarization of Co 2 FeAl 0.5 Si 0.5 for these two direction are almost the same. The next part of this paper is a spin filtering effect using a Co ferrite. The spin filtering effect was observed through a thin Co-ferrite barrier. The inverse type tunnel magnetoresistance ratio of −124% measured at 10 K was obtained. The inverse type magnetoresistance suggests the negative spin polarization of Co-ferrite barrier. The magnetoresistance ratio of −124% corresponds to the spin polarization of −0.77 by the Co-ferrite barrier. The last part is devoted to the spin injection from Co 2 FeAl 0.5 Si 0.5 into GaAs. The spin injection signal was clearly obtained by three terminal Hanle measurement. The spin relaxation time was estimated to be 380 ps measured at 5 K.

  4. Current-induced spin polarization in a spin-polarized two-dimensional electron gas with spin-orbit coupling

    International Nuclear Information System (INIS)

    Wang, C.M.; Pang, M.Q.; Liu, S.Y.; Lei, X.L.

    2010-01-01

    The current-induced spin polarization (CISP) is investigated in a combined Rashba-Dresselhaus spin-orbit-coupled two-dimensional electron gas, subjected to a homogeneous out-of-plane magnetization. It is found that, in addition to the usual collision-related in-plane parts of CISP, there are two impurity-density-free contributions, arising from intrinsic and disorder-mediated mechanisms. The intrinsic parts of spin polarization are related to the Berry curvature, analogous with the anomalous and spin Hall effects. For short-range collision, the disorder-mediated spin polarizations completely cancel the intrinsic ones and the total in-plane components of CISP equal those for systems without magnetization. However, for remote disorders, this cancellation does not occur and the total in-plane components of CISP strongly depend on the spin-orbit interaction coefficients and magnetization for both pure Rashba and combined Rashba-Dresselhaus models.

  5. Using tri-axial accelerometers to identify wild polar bear behaviors

    Science.gov (United States)

    Pagano, Anthony M.; Rode, Karyn D.; Cutting, A.; Owen, M.A.; Jensen, S.; Ware, J.V.; Robbins, C.T.; Durner, George M.; Atwood, Todd C.; Obbard, M.E.; Middel, K.R.; Thiemann, G.W.; Williams, T.M.

    2017-01-01

    Tri-axial accelerometers have been used to remotely identify the behaviors of a wide range of taxa. Assigning behaviors to accelerometer data often involves the use of captive animals or surrogate species, as their accelerometer signatures are generally assumed to be similar to those of their wild counterparts. However, this has rarely been tested. Validated accelerometer data are needed for polar bears Ursus maritimus to understand how habitat conditions may influence behavior and energy demands. We used accelerometer and water conductivity data to remotely distinguish 10 polar bear behaviors. We calibrated accelerometer and conductivity data collected from collars with behaviors observed from video-recorded captive polar bears and brown bears U. arctos, and with video from camera collars deployed on free-ranging polar bears on sea ice and on land. We used random forest models to predict behaviors and found strong ability to discriminate the most common wild polar bear behaviors using a combination of accelerometer and conductivity sensor data from captive or wild polar bears. In contrast, models using data from captive brown bears failed to reliably distinguish most active behaviors in wild polar bears. Our ability to discriminate behavior was greatest when species- and habitat-specific data from wild individuals were used to train models. Data from captive individuals may be suitable for calibrating accelerometers, but may provide reduced ability to discriminate some behaviors. The accelerometer calibrations developed here provide a method to quantify polar bear behaviors to evaluate the impacts of declines in Arctic sea ice.

  6. Polarization-coupled tunable resistive behavior in oxide ferroelectric heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Gruverman, Alexei [Univ. of Nebraska, Lincoln, NE (United States); Tsymbal, Evgeny Y. [Univ. of Nebraska, Lincoln, NE (United States); Eom, Chang-Beom [Univ. of Wisconsin, Madison, WI (United States)

    2017-05-03

    This research focuses on investigation of the physical mechanism of the electrically and mechanically tunable resistive behavior in oxide ferroelectric heterostructures with engineered interfaces realized via a strong coupling of ferroelectric polarization with tunneling electroresistance and metal-insulator (M-I) transitions. This report describes observation of electrically conductive domain walls in semiconducting ferroelectrics, voltage-free control of resistive switching and demonstration of a new mechanism of electrical control of 2D electron gas (2DEG) at oxide interfaces. The research goals are achieved by creating strong synergy between cutting-edge fabrication of epitaxial single-crystalline complex oxides, nanoscale electrical characterization by scanning probe microscopy and theoretical modeling of the observed phenomena. The concept of the ferroelectric devices with electrically and mechanically tunable nonvolatile resistance represents a new paradigm shift in realization of the next-generation of non-volatile memory devices and low-power logic switches.

  7. Self-injection locking of the DFB laser through an external ring fiber cavity: Polarization behavior

    Directory of Open Access Journals (Sweden)

    J.L. Bueno Escobedo

    2016-01-01

    Full Text Available We study stability of self-injection locking realized with DFB laser coupled with an external fiber optic ring cavity. Polarization behavior of the radiation circulating in the feedback loop is reported. Two regimes of mode hopping have been observed; one of them is accompanied by polarization bistability involving two orthogonal polarization states.

  8. Behavioral cardiology: current advances and future directions.

    Science.gov (United States)

    Rozanski, Alan

    2014-07-08

    Growing epidemiological evidence identifies key domains relevant to behavioral cardiology, including health behaviors, emotions, mental mindsets, stress management, social connectedness, and a sense of purpose. Each of these domains exists along a continuum, ranging from positive factors that promote health, to negative factors, which are pathophysiological. To date, there has been relatively little translation of this growing knowledge base into cardiology practice. Four initiatives are proposed to meet this challenge: 1) promulgating greater awareness of the potency of psychosocial risks factors; 2) overcoming a current "artificial divide" between conventional and psychosocial risk factors; 3) developing novel cost-effective interventions using Internet and mobile health applications, group-based counseling, and development of tiered-care behavioral management; and 4) in recognition that "one size does not fit all" with respect to behavioral interventions, developing specialists who can counsel patients in multidisciplinary fashion and use evidence-based approaches for promoting patient motivation and execution of health goals. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  9. Theory of current-induced spin polarization in an electron gas

    Science.gov (United States)

    Gorini, Cosimo; Maleki Sheikhabadi, Amin; Shen, Ka; Tokatly, Ilya V.; Vignale, Giovanni; Raimondi, Roberto

    2017-05-01

    We derive the Bloch equations for the spin dynamics of a two-dimensional electron gas in the presence of spin-orbit coupling. For the latter we consider both the intrinsic mechanisms of structure inversion asymmetry (Rashba) and bulk inversion asymmetry (Dresselhaus), and the extrinsic ones arising from the scattering from impurities. The derivation is based on the SU(2) gauge-field formulation of the Rashba-Dresselhaus spin-orbit coupling. Our main result is the identification of a spin-generation torque arising from Elliot-Yafet scattering, which opposes a similar term arising from Dyakonov-Perel relaxation. Such a torque, which to the best of our knowledge has gone unnoticed so far, is of basic nature, i.e., should be effective whenever Elliott-Yafet processes are present in a system with intrinsic spin-orbit coupling, irrespective of further specific details. The spin-generation torque contributes to the current-induced spin polarization (CISP), also known as inverse spin-galvanic or Edelstein effect. As a result, the behavior of the CISP turns out to be more complex than one would surmise from consideration of the internal Rashba-Dresselhaus fields alone. In particular, the symmetry of the current-induced spin polarization does not necessarily coincide with that of the internal Rashba-Dresselhaus field, and an out-of-plane component of the CISP is generally predicted, as observed in recent experiments. We also discuss the extension to the three-dimensional electron gas, which may be relevant for the interpretation of experiments in thin films.

  10. Magnetic Field Perturbations from Currents in the Dark Polar Regions During Quiet Geomagnetic Conditions

    DEFF Research Database (Denmark)

    Friis-Christensen, Eigil; Finlay, Chris; Hesse, M.

    2017-01-01

    In the day-side sunlit polar ionosphere the varying and IMF dependent convection creates strong ionospheric currents even during quiet geomagnetic conditions. Observations during such times are often excluded when using satellite data to model the internal geomagneticmain field. Observations from...... the night-side or local winter during quiet conditions are, however, also influenced by variations in the IMF. In this paper we briefly review the large scale features of the ionospheric currents in the polar regions with emphasis on the current distribution during undisturbed conditions. We examine...

  11. Determining polar ionospheric electrojet currents from Swarm satellite constellation magnetic data

    DEFF Research Database (Denmark)

    Aakjær, Cecilie Drost; Olsen, Nils; Finlay, Chris

    2016-01-01

    We determine the strength and location of the ionospheric currents responsible for the polar electrojets from magnetic data collected by the Swarm satellite constellation on an orbit-by-orbit basis. The ionospheric currents are modelled using a simple, yet robust, method by a series of line...

  12. Injection and detection of a spin-polarized current in a light-emitting diode

    Science.gov (United States)

    Fiederling, R.; Keim, M.; Reuscher, G.; Ossau, W.; Schmidt, G.; Waag, A.; Molenkamp, L. W.

    1999-12-01

    The field of magnetoelectronics has been growing in practical importance in recent years. For example, devices that harness electronic spin-such as giant-magnetoresistive sensors and magnetoresistive memory cells-are now appearing on the market. In contrast, magnetoelectronic devices based on spin-polarized transport in semiconductors are at a much earlier stage of development, largely because of the lack of an efficient means of injecting spin-polarized charge. Much work has focused on the use of ferromagnetic metallic contacts, but it has proved exceedingly difficult to demonstrate polarized spin injection. More recently, two groups have reported successful spin injection from an NiFe contact, but the observed effects of the spin-polarized transport were quite small (resistance changes of less than 1%). Here we describe a different approach, in which the magnetic semiconductor BexMnyZn1-x-ySe is used as a spin aligner. We achieve injection efficiencies of 90% spin-polarized current into a non-magnetic semiconductor device. The device used in this case is a GaAs/AlGaAs light-emitting diode, and spin polarization is confirmed by the circular polarization state of the emitted light.

  13. Development of a high average current polarized electron source with long cathode operational lifetime

    Energy Technology Data Exchange (ETDEWEB)

    C. K. Sinclair; P. A. Adderley; B. M. Dunham; J. C. Hansknecht; P. Hartmann; M. Poelker; J. S. Price; P. M. Rutt; W. J. Schneider; M. Steigerwald

    2007-02-01

    Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2?105???C/cm2 and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  14. Defect-enhanced Rashba spin-polarized currents in carbon nanotubes

    Science.gov (United States)

    Santos, Hernán; Chico, Leonor; Alvarellos, J. E.; Latgé, A.

    2017-10-01

    The production of spin-polarized currents in pristine carbon nanotubes with Rashba spin-orbit interactions has been shown to be very sensitive to the symmetry of the tubes and the geometry of the setup. Here we analyze the role of defects on the spin quantum conductances of metallic carbon nanotubes due to an external electric field. We show that localized defects, such as adsorbed hydrogen atoms or pentagon-heptagon pairs, increase the Rashba spin-polarized current. Moreover, this enhancement takes place for energies closer to the Fermi energy as compared to the response of pristine tubes. Such increments can be even larger when several equally spaced defects are introduced into the system. We explore different arrangements of defects, showing that for certain geometries there are flips of the spin-polarized current and even transport suppression. Our results indicate that spin valve devices at the nanoscale may be achieved via defect engineering in carbon nanotubes.

  15. Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor

    Science.gov (United States)

    Choi, Seokhwan; Choi, Hyoung Joon; Ok, Jong Mok; Lee, Yeonghoon; Jang, Won-Jun; Lee, Alex Taekyung; Kuk, Young; Lee, SungBin; Heinrich, Andreas J.; Cheong, Sang-Wook; Bang, Yunkyu; Johnston, Steven; Kim, Jun Sung; Lee, Jhinhwan

    2017-12-01

    We explore a new mechanism for switching magnetism and superconductivity in a magnetically frustrated iron-based superconductor using spin-polarized scanning tunneling microscopy (SPSTM). Our SPSTM study on single-crystal Sr2VO3FeAs shows that a spin-polarized tunneling current can switch the Fe-layer magnetism into a nontrivial C4 (2 ×2 ) order, which cannot be achieved by thermal excitation with an unpolarized current. Our tunneling spectroscopy study shows that the induced C4 (2 ×2 ) order has characteristics of plaquette antiferromagnetic order in the Fe layer and strongly suppresses superconductivity. Also, thermal agitation beyond the bulk Fe spin ordering temperature erases the C4 state. These results suggest a new possibility of switching local superconductivity by changing the symmetry of magnetic order with spin-polarized and unpolarized tunneling currents in iron-based superconductors.

  16. Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor.

    Science.gov (United States)

    Choi, Seokhwan; Choi, Hyoung Joon; Ok, Jong Mok; Lee, Yeonghoon; Jang, Won-Jun; Lee, Alex Taekyung; Kuk, Young; Lee, SungBin; Heinrich, Andreas J; Cheong, Sang-Wook; Bang, Yunkyu; Johnston, Steven; Kim, Jun Sung; Lee, Jhinhwan

    2017-12-01

    We explore a new mechanism for switching magnetism and superconductivity in a magnetically frustrated iron-based superconductor using spin-polarized scanning tunneling microscopy (SPSTM). Our SPSTM study on single-crystal Sr_{2}VO_{3}FeAs shows that a spin-polarized tunneling current can switch the Fe-layer magnetism into a nontrivial C_{4} (2×2) order, which cannot be achieved by thermal excitation with an unpolarized current. Our tunneling spectroscopy study shows that the induced C_{4} (2×2) order has characteristics of plaquette antiferromagnetic order in the Fe layer and strongly suppresses superconductivity. Also, thermal agitation beyond the bulk Fe spin ordering temperature erases the C_{4} state. These results suggest a new possibility of switching local superconductivity by changing the symmetry of magnetic order with spin-polarized and unpolarized tunneling currents in iron-based superconductors.

  17. Improved PHIP polarization using a precision, low noise, voltage controlled current source.

    Science.gov (United States)

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Case-study of the evolution of polar-cap currents and auroral electrojets during polar geomagnetic disturbances with IMS magnetometer data

    Energy Technology Data Exchange (ETDEWEB)

    Iijima, T.; Kim, J.S. (State Univ. of New York, Albany (USA). Atmospheric Sciences Research Center); Sugiura, M. (National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center)

    1984-06-01

    By using 1 min average data from the US-Canada IMS network stations (Alaska, east-west and Fort Churchill chains) and also standard magnetograms from stations in the polar-cap region and in the auroral zone, we have examined the development of polar-cap currents and the relationship of their development to the evolution of auroral electrojets during individual polar geomagnetic disturbances. Characteristics that have been determined are reported and discussed.

  19. Magnetic field and electric currents in the vicinity of polar cusps as inferred from Polar and Cluster data

    Directory of Open Access Journals (Sweden)

    N. A. Tsyganenko

    2009-04-01

    Full Text Available A detailed statistical study of the magnetic structure of the dayside polar cusps is presented, based on multi-year sets of magnetometer data of Polar and Cluster spacecraft, taken in 1996–2006 and 2001–2007, respectively. Thanks to the dense data coverage in both Northern and Southern Hemispheres, the analysis spanned nearly the entire length of the cusps, from low altitudes to the cusp "throat" and the magnetosheath. Subsets of data falling inside the polar cusp "funnels" were selected with the help of TS05 and IGRF magnetic field models, taking into account the dipole tilt and the solar wind/IMF conditions. The selection funnels were shifted within ±10° of SM latitude around the model cusp location, and linear regression parameters were calculated for each sliding subset, further divided into 10 bins of distance in the range 2≤R≤12 RE, with the following results. (1 Diamagnetic depression, caused by the penetrated magnetosheath plasma, becomes first visible at R~4–5 RE, rapidly deepens with growing R, peaks at R~6–9 RE, and then partially subsides and widens in latitude at the cusp's outer end. (2 The depression peak is systematically shifted poleward (by ~2° of the footpoint latitude with respect to the model cusp field line, passing through the min{|B|} point at the magnetopause. (3 At all radial distances, clear and distinct peaks of the correlation between the local By and By(IMF and of the corresponding proportionality coefficient are observed. A remarkably regular variation of that coefficient with R quantitatively confirms the field-aligned geometry of the cusp currents associated with the IMF By, found in earlier observations.

  20. Lithological characterization of a contaminated site using Direct current resistivity and time domain Induced Polarization

    DEFF Research Database (Denmark)

    Maurya, Pradip Kumar; Fiandaca, Gianluca; Auken, Esben

    study a large contaminated site in Denmark was investigated using direct current resistivity and time domain induced polarization (DCIP). For this purpose 14 profiles were collected alongside a stream in order to investigate the contamination and delineate the lithological units. 2D inversion using...

  1. Polarization Potential Has No Effect on Maximum Current Density Produced by Halotolerant Bioanodes

    Directory of Open Access Journals (Sweden)

    Muriel González-Muñoz

    2018-03-01

    Full Text Available Halotolerant bioanodes are considered an attractive alternative in microbial electrochemical systems, as they can operate under higher conductive electrolytes, in comparison with traditional wastewater and freshwater bioanodes. The dependency between energetic performance and polarization potential has been addressed in several works; however the vast majority discusses its effect when wastewater or freshwater inocula are employed, and fewer reports focus on inocula from highly-saline environments. Moreover, the effect of the polarization potential on current production is not fully understood. To determine if the polarization potential has a significant effect on current production, eight bioanodes were grown by chronoamperometry at positive and negative potentials relative to the reference electrode (+0.34 V/SHE and −0.16 V/SHE, in a three-electrode set-up employing sediments from a hyperhaline coastal lagoon. The maximum current density obtained was the same, despite the differences in the applied potential. Our findings indicate that even if differences in organic matter removal and coulombic efficiency are obtained, the polarization potential had no statistically significant effect on overall current density production.

  2. Polarized parton distributions from charged-current deep-inelastic scattering

    International Nuclear Information System (INIS)

    Ridolfi, G

    2003-01-01

    We investigate the capabilities of a neutrino factory in the determination of polarized parton distributions from charged-current deep-inelastic scattering experiments, with special attention to the accuracy of this kind of measurements. We show that a neutrino factory would allow to distinguish between different theoretical scenarios for the proton spin structure

  3. Manganite based memristors: Influence of the electroforming polarity on the electrical behavior and radiation hardness

    Energy Technology Data Exchange (ETDEWEB)

    Rubi, D., E-mail: diego.rubi@gmail.com [GIyA and INN, CNEA, Av. Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Escuela de Ciencia y Tecnología, UNSAM, Campus Miguelete, (1650), San Martín, Buenos Aires (Argentina); Kalstein, A.; Román, W.S.; Ghenzi, N.; Quinteros, C. [GIyA and INN, CNEA, Av. Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Mangano, E.; Granell, P. [INTI, CMNB, Av. Gral Paz 5445 (B1650KNA), San Martín, Buenos Aires (Argentina); Golmar, F. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Escuela de Ciencia y Tecnología, UNSAM, Campus Miguelete, (1650), San Martín, Buenos Aires (Argentina); INTI, CMNB, Av. Gral Paz 5445 (B1650KNA), San Martín, Buenos Aires (Argentina); Marlasca, F.G. [GIyA and INN, CNEA, Av. Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); Suarez, S.; Bernardi, G. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Centro Atómico Bariloche (CNEA), Av. E. Bustillo km 9500 (8400), S. C. de Bariloche, Río Negro (Argentina); Albornoz, C. [GIyA and INN, CNEA, Av. Gral Paz 1499, (1650), San Martín, Buenos Aires (Argentina); and others

    2015-05-29

    We report on the fabrication and characterization of La{sub 2/3}Ca{sub 1/3}MnO{sub 3} manganite-based memristive devices. Polycrystalline manganite thin films were grown by Pulsed Laser Deposition, while metallic electrodes were deposited by sputtering. We show that, depending on the polarity of the initial electroforming, both clockwise and anti-clockwise current-voltage curves can be obtained. We attribute this behavior to the coexistence of different resistive switching mechanisms. We finally evaluate the electrical behavior of our devices after irradiation with high energy oxygen ions. We find no significant difference in the dielectric breakdown voltages between irradiated and non-irradiated devices, indicating that they may present radiation hardness and could be therefore appropriate for space or nuclear applications. - Highlights: • n-Si/LCMO/metal memristive devices were fabricated and characterized. • Electroforming polarity controls the activation of different switching mechanisms. • The soft breakdown voltages are not modified after irradiation with oxygen ions.

  4. Magnetic Switching of a Single Molecular Magnet due to Spin-Polarized Current

    OpenAIRE

    Misiorny, Maciej; Barnas, Józef

    2006-01-01

    Magnetic switching of a single molecular magnet (SMM) due to spin-polarized current flowing between ferromagnetic metallic electrodes is investigated theoretically. Magnetic moments of the electrodes are assumed to be collinear and parallel to the magnetic easy axis of the molecule. Electrons tunneling through a barrier between magnetic leads are coupled to the SMM via exchange interaction. The current flowing through the system as well as the spin relaxation times of the SMM are calculated f...

  5. The Current Status of Behaviorism and Neurofeedback

    Science.gov (United States)

    Fultz, Dwight E.

    2009-01-01

    There appears to be no dominant conceptual model for the process and outcomes of neurofeedback among practitioners or manufacturers. Behaviorists are well-positioned to develop a neuroscience-based source code in which neural activity is described in behavioral terms, providing a basis for behavioral conceptualization and education of…

  6. Potentiodynamic polarization study of the corrosion behavior of palladium-silver dental alloys.

    Science.gov (United States)

    Sun, Desheng; Brantley, William A; Frankel, Gerald S; Heshmati, Reza H; Johnston, William M

    2018-04-01

    Although palladium-silver alloys have been marketed for over 3 decades for metal-ceramic restorations, understanding of the corrosion behavior of current alloys is incomplete; this understanding is critical for evaluating biocompatibility and clinical performance. The purpose of this in vitro study was to characterize the corrosion behavior of 3 representative Pd-Ag alloys in simulated body fluid and oral environments and to compare them with a high-noble Au-Pd alloy. The study obtained values of important electrochemical corrosion parameters, with clinical relevance, for the rational selection of casting alloys. The room temperature in vitro corrosion characteristics of the 3 Pd-Ag alloys and the high-noble Au-Pd alloy were evaluated in 0.9% NaCl, 0.09% NaCl, and Fusayama solutions. After simulated porcelain firing heat treatment, 5 specimens of each alloy were immersed in the electrolytes for 24 hours. For each specimen, the open-circuit potential (OCP) was first recorded, and linear polarization was then performed from -20 mV to +20 mV (versus OCP) at a rate of 0.125 mV/s. Cyclic polarization was subsequently performed on 3 specimens of each alloy from -300 mV to +1000 mV and back to -300 mV (versus OCP) at a scanning rate of 1 mV/s. The differences in OCP and corrosion resistance parameters (zero-current potential and polarization resistance) among alloys and electrolyte combinations were compared with the 2-factor ANOVA (maximum-likelihood method) with post hoc Tukey adjustments (α=.05). The 24-hour OCPs and polarization resistance values of the 3 Pd-Ag alloys and the Au-Pd alloy were not significantly different (P=.233 and P=.211, respectively) for the same electrolyte, but significant differences were found for corrosion test results in different electrolytes (Palloy and electrolyte (P=.249 and P=.713, respectively). The 3 Pd-Ag silver alloys appeared to be resistant to chloride ion corrosion, and passivation and de-alloying were identified for these

  7. Development of a high average current polarized electron source with long cathode operational lifetime

    Directory of Open Access Journals (Sweden)

    C. K. Sinclair

    2007-02-01

    Full Text Available Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2×10^{5}   C/cm^{2} and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  8. Thermally Stimulated Current and Polarization Fatigue in Pb(Zr,Ti)O3 Thin Films

    Science.gov (United States)

    Okino, Hirotake; Toyoda, Yoshiaki; Shimizu, Masaru; Horiuchi, Toshihisa; Shiosaki, Tadashi; Matsushige, Kazumi

    1998-09-01

    In order to clarify the origin of the polarization fatigue phenomena,charge traps in ferroelectric Pb(Zr,Ti)O3 (PZT) thin filmswere measured using the thermally stimulated current (TSC) technique.For polarization fatigued Pt/PZT/Pt/SiO2/Si(100) capacitors,a peak of TSC was observed, andthe trap density estimated from the TSC dataincreased as switching cycles increased.Activation energy and density of the charge trapswere estimated to be 0.7 0.8 eV andon the order of 1018 cm-3,respectively.It was also observed thatdegradation of remanent polarization of PZTwas improved by the TSC measurement process.On the other hand, no TSC peak was observed forfatigue free Ir/PZT/Ir/IrO2/SiO2/Si(100) capacitors.From these results, it was suggested thatthe main origin of the polarization fatigue phenomenawas the domain pinning caused by trapped charge carriersinjected by polarization reversal.

  9. Influence of Neutral Currents on Electron and Gamma Polarizations in the Process e+N→e′+N+γ

    International Nuclear Information System (INIS)

    Ousmane Manga, Adamou; Moussa, Aboubacar; Aboubacar, Almoustapha; Samsonenko, N. V.

    2014-01-01

    The differential cross section of electron inelastic scattering by nuclei followed by γ radiation is calculated using the multipole decomposition of the hadronic currents and by taking into account the longitudinal polarization of the initial electron and the circular polarization of the γ radiation. We performed the analysis of the angular and energy dependence of the degree of electron and photon polarization which can yield information on values of weak neutral currents parameters

  10. Phase Behavior of Laundry Surfactants in Polar Solvents

    NARCIS (Netherlands)

    Stuart, Marc C.A.; Pas, John C. van de; Engberts, Jan B.F.N.

    2006-01-01

    Laundry surfactants are usually mixtures of ionic and nonionic detergents that exhibit a complex phase behavior. Here the ternary phase behavior of an isotropic and a liquid crystalline (LC) surfactant mixture has been examined in water/solvent systems. The size of the LC area in the ternary phase

  11. Demographic and traditional knowledge perspectives on the current status of Canadian polar bear subpopulations.

    Science.gov (United States)

    York, Jordan; Dowsley, Martha; Cornwell, Adam; Kuc, Miroslaw; Taylor, Mitchell

    2016-05-01

    Subpopulation growth rates and the probability of decline at current harvest levels were determined for 13 subpopulations of polar bears (Ursus maritimus) that are within or shared with Canada based on mark-recapture estimates of population numbers and vital rates, and harvest statistics using population viability analyses (PVA). Aboriginal traditional ecological knowledge (TEK) on subpopulation trend agreed with the seven stable/increasing results and one of the declining results, but disagreed with PVA status of five other declining subpopulations. The decline in the Baffin Bay subpopulation appeared to be due to over-reporting of harvested numbers from outside Canada. The remaining four disputed subpopulations (Southern Beaufort Sea, Northern Beaufort Sea, Southern Hudson Bay, and Western Hudson Bay) were all incompletely mark-recapture (M-R) sampled, which may have biased their survival and subpopulation estimates. Three of the four incompletely sampled subpopulations were PVA identified as nonviable (i.e., declining even with zero harvest mortality). TEK disagreement was nonrandom with respect to M-R sampling protocols. Cluster analysis also grouped subpopulations with ambiguous demographic and harvest rate estimates separately from those with apparently reliable demographic estimates based on PVA probability of decline and unharvested subpopulation growth rate criteria. We suggest that the correspondence between TEK and scientific results can be used to improve the reliability of information on natural systems and thus improve resource management. Considering both TEK and scientific information, we suggest that the current status of Canadian polar bear subpopulations in 2013 was 12 stable/increasing and one declining (Kane Basin). We do not find support for the perspective that polar bears within or shared with Canada are currently in any sort of climate crisis. We suggest that monitoring the impacts of climate change (including sea ice decline) on polar bear

  12. Individual effects of seasonal changes, visitor density, and concurrent bear behavior on stereotypical behaviors in captive polar bears (Ursus maritimus).

    Science.gov (United States)

    Kelly, Krista R; Harrison, Michelle L; Size, Daniele D; MacDonald, Suzanne E

    2015-01-01

    Stereotypical behaviors in captive polar bears (Ursus maritimus) can be detrimental to their welfare. These behaviors can be reduced through enrichment programs but are often not completely eliminated, so identifying potential triggers is important. The present study investigated the influences of seasonal changes, visitor density, and concurrent bear activity on stereotypical behaviors exhibited by 3 captive polar bears at the Toronto Zoo. All bears exhibited these behaviors; however, individual differences were found in duration and form. The male exhibited less stereotypical behavior during spring, and the females exhibited less stereotypical behavior during winter. An increase in visitor density was associated with more stereotypical behavior in 1 female but less stereotypical behavior in the other 2 bears. All bears engaged in more stereotypical behaviors when the other bears were inactive, and 1 female engaged in more stereotypical behaviors when the other bears were out of sight. Further, when conspecifics were active, all bears engaged in less stereotypical behaviors. Given the variability among individual bears, future enrichment programs must be tailored to the needs of individuals to maximize efficacy.

  13. Influence of Direct Current Electric Field on Corrosion Behavior of Tin Under a Thin Electrolyte Layer

    Science.gov (United States)

    Huang, H. L.; Bu, F. R.; Tian, J.; Liu, D.

    2017-12-01

    The influence of a direct current electric field (DCEF) on corrosion behavior of tin under a thin electrolyte layer was investigated based on an array electrode technology by polarization, electrochemical impedance spectroscopy and surface analysis. The experimental results indicate that the corrosion rate of tin near the positive plate of DCEF increases with increased electric field intensity, which could be attributed to the acceleration of the migration of ions, the removal of corrosion products under DCEF and the damage of tin surface oxide film. Furthermore, tin at different positions in a DCEF exhibits different corrosion behavior, which could be ascribed to the difference of the local corrosion environment caused by the DCEF.

  14. Magnetic switching of a single molecular magnet due to spin-polarized current

    Science.gov (United States)

    Misiorny, Maciej; Barnaś, Józef

    2007-04-01

    Magnetic switching of a single molecular magnet (SMM) due to spin-polarized current flowing between ferromagnetic metallic leads (electrodes) is investigated theoretically. Magnetic moments of the leads are assumed to be collinear and parallel to the magnetic easy axis of the molecule. Electrons tunneling through the barrier between magnetic leads are coupled to the SMM via exchange interaction. The current flowing through the system, as well as the spin relaxation times of the SMM, are calculated from the Fermi golden rule. It is shown that spin of the SMM can be reversed by applying a certain voltage between the two magnetic electrodes. Moreover, the switching may be visible in the corresponding current-voltage characteristics.

  15. On the limit of field-aligned current intensity in the polar magnetosphere

    International Nuclear Information System (INIS)

    Cole, K.D.

    1991-01-01

    Field-aligned current (FAC) is here defined by 4πj=αβ, where α is constant along a magnetic field line. The upper limit value of α in the polar magnetosphere, possible source regions of the strongest FAC and the relationship of them to some auroral and ionospheric irregularity cross-field scale sizes are discussed. Cross-field dimensions of the strongest FAC are related to the gyroradii of source particles (O + , He ++ , H + , E) in the current-generating region. It is suggested that experimental determination, and mapping of the values of α, may assist with the search for the generators of such currents in near-Earth space including in the nearby solar wind. The authors associate the upper limit of α with the breakup of FAC systems

  16. Investigation of Current Induced Spin Polarization in III-V Semiconductor Epilayers

    Science.gov (United States)

    Luengo-Kovac, Marta

    In the development of a semiconductor spintronics device, a thorough understanding of spin dynamics in semiconductors is necessary. In particular, electrical control of electron spins is advantageous for its compatibility with present day electronics. In this thesis, we will discuss the electrical modification of the electron g-factor, which characterizes the strength of the interaction between a spin and a magnetic field, as well as investigate electrically generated spin polarizations as a function of various material parameters. We report on the modification of the electron g-factor by an in-plane electric field in an InGaAs epilayer. We performed external magnetic field scans of the Kerr rotation of the InGaAs film in order to measure the g-factor independently of the spin-orbit fields. The g-factor increases from -0.4473(0.0001) at 0 V/cm to -0.4419( 0.0001) at 50 V/cm applied along the [110] crystal axis. A comparison of temperature and voltage dependent photoluminescence measurements indicate that minimal channel heating occurs at these voltages. Possible explanations for this g-factor modification are discussed, including an increase in the electron temperature that is independent of the lattice temperature and the modification of the donor-bound electron wave function by the electric field. The current-induced spin polarization and momentum-dependent spin-orbit field were measured in InGaAs epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the spin polarization mechanism is extrinsic. Temperature-dependent measurements of the spin dephasing rates and mobilities were used to characterize the relative strengths of the intrinsic D

  17. Harmonic Mitigation Using a Polarized Ramp-time Current-Controlled Inverter

    Directory of Open Access Journals (Sweden)

    Lawrence J. Borle

    2010-12-01

    Full Text Available This paper describes the implementation of a shunt active power filter for a three-phase four-wire system to compensate for power quality problems generated by mixed non-linear loads, which are a combination of harmonic, reactive and unbalanced components. The filter is a three-phase current-controlled voltage source inverter (CC-VSI with a filter inductor at the AC output and a DC-bus capacitor. The CC-VSI is operated to directly control the grid current to be sinusoidal and in phase with the grid voltage without sensing the load currents. The switching is controlled using polarized ramp-time current control, which is based on the concept of zero average current error (ZACE with a fixed switching frequency. The laboratory experiment results indicate that the filter is able to mitigate predominantly the harmonics, as well as the reactive power, so that the grid currents are sinusoidal, in phase with the grid voltages and symmetrical although the grid voltage contains harmonics.

  18. Enhancing current-induced torques by abutting additional spin polarizer layer to nonmagnetic metal layer

    Science.gov (United States)

    Go, Gyungchoon; Lee, Kyung-Jin; Kim, Young Keun

    2017-04-01

    Recently, the switching of a perpendicularly magnetized ferromagnet (FM) by injecting an in-plane current into an attached non-magnet (NM) has become of emerging technological interest. This magnetization switching is attributed to the spin-orbit torque (SOT) originating from the strong spin-orbit coupling of the NM layer. However, the switching efficiency of the NM/FM structure itself may be insufficient for practical use, as for example, in spin transfer torque (STT)-based magnetic random access memory (MRAM) devices. Here we investigate spin torque in an NM/FM structure with an additional spin polarizer (SP) layer abutted to the NM layer. In addition to the SOT contribution, a spin-polarized current from the SP layer creates an extra spin chemical potential difference at the NM/FM interface and gives rise to a STT on the FM layer. We show that, using typical parameters including device width, thickness, spin diffusion length, and the spin Hall angle, the spin torque from the SP layer can be much larger than that from the spin Hall effect (SHE) of the NM.

  19. Differences between signal currents for both polarities of applied voltages on cavity ionization chambers

    International Nuclear Information System (INIS)

    Takata, N.

    2000-01-01

    It is necessary to obtain precise values of signal currents for the measurement of exposure rates for gamma rays with cavity ionization chambers. Signal currents are usually expected to have the same absolute values for both polarities of applied voltages. In the case of cylindrical cavity ionization chambers, volume recombination loss of ion pairs depends on the polarity of the applied voltage. This is because the values of mobility are different for positive and negative ions. It was found, however, that values of signal currents from a cylindrical ionization chamber change slightly more with a negative than with a positive applied voltage, even after being corrected for volume recombination loss. Moreover, absolute values of saturation currents, which are obtained by extrapolation of correction of initial recombination and diffusion loss, were larger for the negative than for the positive applied voltage. It is known from an experiment with parallel plate ionization chambers that when negative voltage is applied to the repeller electrode, the saturated signal current decreases with an increase in the applied voltage. This is because secondary electrons are accelerated and the stopping power of air for these electrons decreases. When positive voltage is applied, the reverse is true. The effects of acceleration and deceleration of secondary electrons by the electric field thus seem to cause a tendency opposite to the experimental results on the signal currents from cylindrical ionization chambers. The experimental results for the cylindrical ionization chamber can be explained as follows. When negative voltage is applied, secondary electrons are attracted to the central (collecting) electrode. Consequently, the path length of the trajectories of these secondary electrons in the ionization volume increases and signal current increases. The energy gain from the electric field by secondary electrons which stop in the ionization chamber also contributes to the

  20. Photoinduced electric currents in ring-shaped molecules by circularly polarized laser pulses

    International Nuclear Information System (INIS)

    Nobusada, Katsuyuki; Yabana, Kazuhiro

    2007-01-01

    We have theoretically demonstrated that circularly polarized laser pulses induce electric currents and magnetic moments in ring-shaped molecules Na 10 and benzene. The time-dependent adiabatic local density approximation is employed for this purpose, solving the time-dependent Kohn-Sham equation in real space and real time. It has been found that the electric currents are induced efficiently and persist continuously even after the laser pulses were switched off provided the frequency of the applied laser pulse is in tune with the excitation energy of the electronic excited state with the dipole strength for each molecular system. The electric currents are definitely revealed to be a second-order nonlinear optical response to the magnitude of the electric field. The magnetic dipole moments inevitably accompany the ring currents, so that the molecules are magnetized. The production of the electric currents and the magnetic moments in the present procedure is found to be much more efficient than that utilizing static magnetic fields

  1. Current-induced spin polarization in InGaAs and GaAs epilayers with varying doping densities

    Science.gov (United States)

    Luengo-Kovac, M.; Huang, S.; Del Gaudio, D.; Occena, J.; Goldman, R. S.; Raimondi, R.; Sih, V.

    2017-11-01

    The current-induced spin polarization and momentum-dependent spin-orbit field were measured in InxGa1 -xAs epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the extrinsic contributions to the spin-polarization mechanism must be considered. Theoretical calculations based on a model that includes extrinsic contributions to the spin dephasing and the spin Hall effect, in addition to the intrinsic Rashba and Dresselhaus spin-orbit coupling, are found to reproduce the experimental finding that the crystal direction with the smaller net spin-orbit field has larger electrical spin generation efficiency and are used to predict how sample parameters affect the magnitude of the current-induced spin polarization.

  2. Mapping geological structures in bedrock via large-scale direct current resistivity and time-domain induced polarization tomography

    DEFF Research Database (Denmark)

    Rossi, Matteo; Olsson, Per-Ivar; Johansson, Sara

    2017-01-01

    An investigation of geological conditions is always a key point for planning infrastructure constructions. Bedrock surface and rock quality must be estimated carefully in the designing process of infrastructures. A large direct-current resistivity and time-domain induced-polarization survey has......, there are northwest-trending Permian dolerite dykes that are less deformed. Four 2D direct-current resistivity and time-domain induced-polarization profiles of about 1-km length have been carefully pre-processed to retrieve time-domain induced polarization responses and inverted to obtain the direct......-current resistivity distribution of the subsoil and the phase of the complex conductivity using a constant-phase angle model. The joint interpretation of electrical resistivity and induced-polarization models leads to a better understanding of complex three-dimensional subsoil geometries. The results have been...

  3. Joint Polar Satellite System (JPSS) Common Ground System (CGS) Current Technical Performance Measures

    Science.gov (United States)

    Cochran, S.; Panas, M.; Jamilkowski, M. L.; Miller, S. W.

    2015-12-01

    ABSTRACT The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). The Joint Polar Satellite System will replace the afternoon orbit component and ground processing system of the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA. The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological and geophysical observations of the Earth. The ground processing system for JPSS is known as the JPSS Common Ground System (JPSS CGS). Developed and maintained by Raytheon Intelligence, Information and Services (IIS), the CGS is a multi-mission enterprise system serving NOAA, NASA and their national and international partners. The CGS has demonstrated its scalability and flexibility to incorporate multiple missions efficiently and with minimal cost, schedule and risk, while strengthening global partnerships in weather and environmental monitoring. The CGS architecture is being upgraded to Block 2.0 in 2015 to "operationalize" S-NPP, leverage lessons learned to date in multi-mission support, take advantage of more reliable and efficient technologies, and satisfy new requirements and constraints in the continually evolving budgetary environment. To ensure the CGS meets these needs, we have developed 49 Technical Performance Measures (TPMs) across 10 categories, such as data latency, operational availability and scalability. This paper will provide an overview of the CGS Block 2.0 architecture, with particular focus on the 10 TPM categories listed above. We will provide updates on how we ensure the deployed architecture meets these TPMs to satisfy our multi-mission objectives with the deployment of Block 2.0.

  4. Behavioral decisions for managing social distance and aggression in captive polar bears (Ursus maritimus).

    Science.gov (United States)

    Renner, Michael J; Kelly, Aislinn L

    2006-01-01

    The polar bear (Ursus maritimus) in most zoos attracts high levels of public attention and can play an important role in conservation education. Polar bears in the wild are typically solitary; bears in captivity often house socially. This study reported behavioral evidence on how bears manage this situation and whether proximity leads to aggression. The study recorded location and behavior once per minute for 106 hr for 2 female polar bears at the Philadelphia Zoo; the samples represented all times of day bears spent in the enclosure (off-exhibit time spent in separate, indoor dens). When changing locations, 1 bear more frequently moved away from the other, effecting a net increase in interindividual distance. When either bear moved into an adjacent zone, 1 typically moved away. The bears occupied the same enclosure zone for a low proportion of time; proximity did not routinely lead to overt aggression. These data indicate polar bears make behavioral decisions, minimizing aggression, to manage social distance and that enclosure designers for solitary species--to facilitate social avoidance--should consider using topographical complexity and multiple pathways throughout.

  5. The influence of current mood state, number of previous affective episodes and predominant polarity on insight in bipolar disorder.

    Science.gov (United States)

    de Assis da Silva, Rafael; Mograbi, Daniel C; Camelo, Evelyn Vieira Miranda; Peixoto, Ursula; Santana, Cristina Maria Teixeira; Landeira-Fernandez, Jesus; Morris, Robin G; Cheniaux, Elie

    2017-11-01

    Although many studies have explored the effect of current affective episodes on insight into bipolar disorder, the potential interaction between current mood state and previous affective episodes has not been consistently investigated. To explore the influence of dominant polarity, number of previous affective episodes and current affective state on insight in bipolar disorder patients in euthymia or mania. A total of 101 patients with bipolar disorder were recruited for the study, including 58 patients in euthymia (30 with no defined predominant polarity and 28 with manic predominant polarity) and 43 in mania (26 with no defined predominant polarity and 17 with manic predominant polarity). Patients underwent a clinical assessment and insight was evaluated through the Insight Scale for Affective Disorders. Bipolar disorder patients in mania had worse insight than those in euthymia, with no effect of dominant polarity. In addition, positive psychotic symptoms showed a significant effect on insight and its inclusion as a covariate eliminated differences related to mood state. Finally, the number of previous manic or depressive episodes did not correlate with insight level. Mania is a predictor of loss of insight into bipolar disorder. However, it is possible that its contribution is linked to the more frequent presence of psychotic symptoms in this state. Dominant polarity and number/type of previous affective episodes have a limited impact on insight.

  6. Hole dynamics and spin currents after ionization in strong circularly polarized laser fields

    International Nuclear Information System (INIS)

    Barth, Ingo; Smirnova, Olga

    2014-01-01

    We apply the time-dependent analytical R-matrix theory to develop a movie of hole motion in a Kr atom upon ionization by strong circularly polarized field. We find rich hole dynamics, ranging from rotation to swinging motion. The motion of the hole depends on the final energy and the spin of the photoelectron and can be controlled by the laser frequency and intensity. Crucially, hole rotation is a purely non-adiabatic effect, completely missing in the framework of quasistatic (adiabatic) tunneling theories. We explore the possibility to use hole rotation as a clock for measuring ionization time. Analyzing the relationship between the relative phases in different ionization channels we show that in the case of short-range electron-core interaction the hole is always initially aligned along the instantaneous direction of the laser field, signifying zero delays in ionization. Finally, we show that strong-field ionization in circular fields creates spin currents (i.e. different flow of spin-up and spin-down density in space) in the ions. This phenomenon is intimately related to the production of spin-polarized electrons in strong laser fields Barth and Smirnova (2013 Phys. Rev. A 88 013401). We demonstrate that rich spin dynamics of electrons and holes produced during strong field ionization can occur in typical experimental conditions and does not require relativistic intensities or strong magnetic fields. (paper)

  7. Domain Wall Dynamics Driven by a Localized Injection of a Spin-Polarized Current

    Science.gov (United States)

    Finocchio, Giovanni; Maugeri, Natale; Torres, Luis; Azzerboni, Bruno

    2010-06-01

    This paper introduces an oscillator scheme based on the oscillations of magnetic domain walls due to spin-polarized currents, where the current is injected perpendicular to the sample plane in a localized part of a nanowire. Depending on the geometrical and physical characteristic of the system, we identify two different dynamical regimes (auto-oscillations) when an out-of-plane external field is applied. The first regime is characterized by nucleation of domain walls (DWs) below the current injection site and the propagation of those up to the end of the nanowire, we also found an oscillation frequency larger than 5GHz with a linear dependence on the applied current density. This simple system can be used as a tuneable steady-state domain wall oscillator. In the second dynamical regime, we observe the nucleation of two DWs which propagate back and forth in the nanowire with a sub-GHz oscillation frequency. The micromagnetic spectral mapping technique shows the spatial distribution of the output power is localized symmetrically in the nanowire. We suggest that this configuration can be used as micromagnetic transformer to decouple electrically two different circuits.

  8. Polarization-selective vortex-core switching by tailored orthogonal Gaussian-pulse currents

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Young-Sang; Lee, Ki-Suk; Jung, Hyunsung; Choi, Youn-Seok; Yoo, Myoung-Woo; Han, Dong-Soo; Im, Mi-Young; Fischer, Peter; Kim, Sang-Koog

    2011-05-01

    We experimentally demonstrate low-power-consumption vortex-core switching in magnetic nanodisks using tailored rotating magnetic fields produced with orthogonal and unipolar Gaussian-pulse currents. The optimal width of the orthogonal pulses and their time delay are found, from analytical and micromagnetic numerical calculations, to be determined only by the angular eigenfrequency ωD for a given vortex-state disk of polarization p, such that σ=1/ωD and Δt=π/2p/ωD. The estimated optimal pulse parameters are in good agreement with the experimental results. Finally, this work lays a foundation for energy-efficient information recording in vortex-core cross-point architecture.

  9. Asymmetrical edges induced strong current-polarization in embedded graphene nanoribbons

    Science.gov (United States)

    Li, Kuanhong; Zhang, Xiang-Hua

    2018-05-01

    We investigate the electronic structures and transport properties of the embedded zigzag graphene nanoribbon (E-ZGNR) in hexagonal boron nitride trenches, which are achievable in recent experiments. Our first principles results show that the E-ZGNR has a significant enhanced conductivity relative to common ZGNRs due to the existence of asymmetrical edge structures. Moreover, only one spin-orientation electrons possess a widely opened band gap at the magnetic ground state with anti-ferromagnetic configuration, resulting in a full current-polarization at low bias region. Our findings indicate that the state-of-the-art embedding technology is quite useful for tuning the electronic structure of ZGNR and building possible spin injection and spin filter devices in spintronics.

  10. Polar bodies in assisted reproductive technology: current progress and future perspectives.

    Science.gov (United States)

    Wei, Yanchang; Zhang, Teng; Wang, Ya-Peng; Schatten, Heide; Sun, Qing-Yuan

    2015-01-01

    During meiotic cell-cycle progression, unequal divisions take place, resulting in a large oocyte and two diminutive polar bodies. The first polar body contains a subset of bivalent chromosomes, whereas the second polar body contains a haploid set of chromatids. One unique feature of the female gamete is that the polar bodies can provide beneficial information about the genetic background of the oocyte without potentially destroying it. Therefore, polar body biopsies have been applied in preimplantation genetic diagnosis to detect chromosomal or genetic abnormalities that might be inherited by the offspring. Besides the traditional use in preimplantation diagnosis, recent findings suggest additional important roles for polar bodies in assisted reproductive technology. In this paper, we review the new roles of polar bodies in assisted reproductive technology, mainly focusing on single-cell sequencing of the polar body genome to deduce the genomic information of its sibling oocyte and on polar body transfer to prevent the transmission of mtDNA-associated diseases. We also discuss additional potential roles for polar bodies and related key questions in human reproductive health. We believe that further exploration of new roles for polar bodies will contribute to a better understanding of reproductive health and that polar body manipulation and diagnosis will allow production of a greater number of healthy babies. © 2015 by the Society for the Study of Reproduction, Inc.

  11. The association of current smoking behavior with the smoking behavior of parents, siblings, friends and spouses

    NARCIS (Netherlands)

    Vink, J.M.; Willemsen, G.; Boomsma, D.I.

    2003-01-01

    Aims: To examine the association of current smoking behavior of adolescents and young adults with the smoking behavior of their parents, siblings, friends and spouses. Design: Using survey data from a large twin-family sample, the association between the smoking behavior of participants and that of

  12. Study of the polar current systems using the IMS meridian chains of magnetometers. Pt. 1. Alaska meridian chain

    Energy Technology Data Exchange (ETDEWEB)

    Akasofu, S.I.; Ahn, B.H.; Romick, G.J. (Alaska Univ., Fairbanks (USA). Geophysical Inst.)

    1983-12-01

    Magnetic field data from a meridian chain of observatories and the recently developed computer codes constitute a powerful tool in studying substorm current systems in the polar region. In this paper, we summarize some of the results obtained from the IMS Alaska meridian chain of observatories. The basic data are the average daily magnetic field variations for 50 successive days (March 9- April 27, 28) which represent a moderately disturbed period. With the aid of the two computer codes, we obtained the distribution of the following quantities in the polar ionosphere in invariant-MLT coordinates: the total ionospheric current; the Pedersen current; the Hall current; the field-aligned currents; the Pedersen-associated field-aligned currents; the Hall-associated field-aligned currents; the electric potential; the Joule heat production rate; the auroral particle energy injection rate; the total energy dissipation rate. All these quantities are related to each other self-consistently at every point under the initial assumptions used in the computation. By using a model of the magnetosphere, the following quantities in the polar ionosphere are projected onto the equatorial plane and the Y-Z plane at X = -20 Rsub(E): the Pedersen current counterpart; the Hall current counterpart; the electric potential; the Pedersen-associated field-aligned currents; the Hall-associated field-aligned currents. These distributions patterns serve as an important basis for studying the generation mechanisms of substorm current systems and the magnetosphere-ionosphere coupling process.

  13. Thermally induced pure and spin polarized currents in a zigzag silicene nanoribbon based FM/normal/AFM junction

    Science.gov (United States)

    Ghanbari, Atousa; Esmaeilzadeh, Mahdi; Pournaghavi, Nezhat

    2018-01-01

    We study thermally induced spin resolved current in a zigzag silicene nanoribbon when the left and right leads are respectively affected by ferromagnetic (FM) and anti-ferromagnetic (AFM) exchange fields (FM/normal/AFM junction). We show that pure spin current is generated due to the leads temperature difference and the junction can work as a spin Seebeck diode. The pure spin current can be easily controlled by a perpendicular electric field and the junction, in this case, can work as a spin current switch. In addition, we study the effect of a single vacancy and show that the vacancy can slightly destroy the pure spin current property which leads to induce a weak spin polarized current. In the presence of both vacancy and electric field, current with high and tunable spin polarization can be achieved.

  14. The influence of preferred orientation and poling temperature on the polarization switching current in PZT thin films

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Mi; Zhang, Weikang; Zhang, Zebin; Zhang, Ping [Tianjin University, School of Electrical and Information Engineering, Tianjin (China); Lan, Kuibo [Tianjin University, School of Microelectronics, Tianjin (China)

    2017-07-15

    In this paper, Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) thin films with different preferred orientation were prepared on platinized silicon substrates by a modified sol-gel method. Our results indicate that the polarization switching current in PZT thin films is dependent on preferred orientation and poling temperature. In our measurements, (111)-oriented PZT has a larger polarization switching current than randomly oriented PZT, and with the increase of the degree of (111) preferred orientation and the poling temperature, the polarization switching current gradually increase. Considering the contact of PZT thin film with electrodes, the space-charged limited conduction (SCLC) combined with domain switching mechanism may be responsible for such phenomena. By analyzing the conduction data, we found the interface-limited Schottky emission (ES) and bulk-limited Poole-Frenkel hopping (PF) are not suitable for our samples. (orig.)

  15. [Relationship between current smoking behaviors and household characteristics in Guangdong].

    Science.gov (United States)

    Cao, Rong; Cai, Qiumao; Xu, Yanjun; Xu, Xiaojun; Ma, Wenjun; Wu, Wei; Hao, Aihua; Zhang, Rongyu; He, Yanhui; He, Qun

    2014-05-01

    To disclose the relationship between current smoking behaviors and household characteristics among adults in Guangdong, in order to provide scientific evidence for household tobacco control strategy. A questionnaire survey was conducted among the adults sampled by four-stage randomized cluster sampling in ten districts of five cities in Guangdong from September to November, 2010. The questionnaire included demographic characteristics, smoking behaviors and smoking-related household characteristics. Chi-square test and unconditional logistic regression analysis were employed to explore the relationship between current smoking behaviors and household characteristics. This study included 2 150 respondents, with data from 2 121 eligible questionnaires used for analysis. The current smoking rates for respondents with household characteristics including per capita household income below 1 000 Yuan, three or more smokers in the family, no ban of smoking at home and treating visitors with cigarettes were 28.7%, 56.5%, 34.2% and 43.5% , respectively, and were significantly higher than those for respondents with household characteristics at other levels (P smoking restrictions at home and treating visitors with cigarettes had significant association with current smoking behaviors (P smoke-free homes, encourage smoking cessation and treat visitors with no cigarettes.

  16. Migrational polarization in high-current density molten salt electrochemical devices

    Energy Technology Data Exchange (ETDEWEB)

    Braunstein, J.; Vallet, C.E.

    1977-01-01

    Electrochemical flux equations based on the thermodynamics of irreversible processes have been derived in terms of experimental transport coefficients for binary molten salt mixtures analogous to those proposed for high temperature batteries and fuel cells. The equations and some numerical solutions indicate steady state composition gradients of significant magnitude. The effects of migrational separation must be considered along with other melt properties in the characterization of electrode behavior, melt composition, operating temperatures and differences of phase stability, wettability and other physicochemical properties at positive and negative electrodes of high current density devices with mixed electrolytes.

  17. Polarity Specific Suppression Effects of Transcranial Direct Current Stimulation for Tinnitus

    Directory of Open Access Journals (Sweden)

    Kathleen Joos

    2014-01-01

    Full Text Available Tinnitus is the perception of a sound in the absence of an external auditory stimulus and affects 10–15% of the Western population. Previous studies have demonstrated the therapeutic effect of anodal transcranial direct current stimulation (tDCS over the left auditory cortex on tinnitus loudness, but the effect of this presumed excitatory stimulation contradicts with the underlying pathophysiological model of tinnitus. Therefore, we included 175 patients with chronic tinnitus to study polarity specific effects of a single tDCS session over the auditory cortex (39 anodal, 136 cathodal. To assess the effect of treatment, we used the numeric rating scale for tinnitus loudness and annoyance. Statistical analysis demonstrated a significant main effect for tinnitus loudness and annoyance, but for tinnitus annoyance anodal stimulation has a significantly more pronounced effect than cathodal stimulation. We hypothesize that the suppressive effect of tDCS on tinnitus loudness may be attributed to a disrupting effect of ongoing neural hyperactivity, independent of the inhibitory or excitatory effects and that the reduction of annoyance may be induced by influencing adjacent or functionally connected brain areas involved in the tinnitus related distress network. Further research is required to explain why only anodal stimulation has a suppressive effect on tinnitus annoyance.

  18. Using Transcranial Direct Current Stimulation to Enhance Creative Cognition: Interactions between Task, Polarity, and Stimulation Site

    Directory of Open Access Journals (Sweden)

    Adam B. Weinberger

    2017-05-01

    Full Text Available Creative cognition is frequently described as involving two primary processes, idea generation and idea selection. A growing body of research has used transcranial direct current stimulation (tDCS to examine the neural mechanisms implicated in each of these processes. This literature has yielded a diverse set of findings that vary depending on the location and type (anodal, cathodal, or both of electrical stimulation employed, as well as the task’s reliance on idea generation or idea selection. As a result, understanding the interactions between stimulation site, polarity and task demands is required to evaluate the potential of tDCS to enhance creative performance. Here, we review tDCS designs that have elicited reliable and dissociable enhancements for creative cognition. Cathodal stimulation over the left inferior frontotemporal cortex has been associated with improvements on tasks that rely primarily on idea generation, whereas anodal tDCS over left dorsolateral prefrontal cortex (DLPFC and frontopolar cortex has been shown to augment performance on tasks that impose high demands on creative idea selection. These results highlight the functional selectivity of tDCS for different components of creative thinking and confirm the dissociable contributions of left dorsal and inferior lateral frontotemporal cortex for different creativity tasks. We discuss promising avenues for future research that can advance our understanding of the effectiveness of tDCS as a method to enhance creative cognition.

  19. Mapping geological structures in bedrock via large-scale direct current resistivity and time-domain induced polarization tomography

    DEFF Research Database (Denmark)

    Rossi, Matteo; Olsson, Per-Ivar; Johansson, Sara

    2017-01-01

    An investigation of geological conditions is always a key point for planning infrastructure constructions. Bedrock surface and rock quality must be estimated carefully in the designing process of infrastructures. A large direct-current resistivity and time-domain induced-polarization survey has b...... been performed in Dalby, Lund Municipality, southern Sweden, with the aim of mapping lithological variations in bedrock. The geology at the site is characterised by Precambrian granitic gneisses and amphibolites, which are intensely deformed, fractured, and partly weathered. In addition......-polarization profiles. The direct-current resistivity and time-domain induced-polarization methodology proved to be a suitable technique for extensively mapping weathered zones with poor geotechnical characteristics and tectonic structures, which can lead to severe problems for infrastructure construction and....../or constitute risk zones for aquifer contamination....

  20. Post-den emergence behavior of polar bears (Ursus maritimus) in Northern Alaska

    Science.gov (United States)

    Smith, T.S.; Partridge, Steven T.; Amstrup, Steven C.; Schliebe, S.

    2007-01-01

    We observed polar bear (Ursus maritimus) maternity den sites on Alaska’s North Slope in March 2002 and 2003 in an effort to describe bears’ post-den emergence behavior. During 40 sessions spanning 459 h, we observed 8 adults and 14 dependent cubs outside dens for 37.5 h (8.2% of total observation time). There was no significant difference between den emergence dates in 2002 (mean = 15 Mar ± 4.1 d) and 2003 (mean = 21 Mar ± 2.1 d). Following initial den breakout, polar bears remained at their den sites for 1.5 to 14 days (mean = 8.1 ± 5.1 d). The average length of stay in dens between emergent periods was significantly shorter in 2002 (1.79 h) than in 2003 (4.82 h). While outside, adult bears were inactive 49.5% of the time, whereas cubs were inactive 13.4% of the time. We found no significant relationships between den emergence activity and weather. Adult polar bears at den sites subjected to industrial activity exhibited significantly fewer bouts of vigilance than denned bears in undisturbed areas (t = -5.5164, df = 4, p= 0.00). However, the duration of vigilance behaviors at sites near industrial activity was not significantly shorter than at the other sites studied (t = -1.8902, df = 4, p = 0.07). Results for these bears were within the range of findings in other studies of denned polar bears.

  1. Nuclear reactor fuel rod behavior modelling and current trends

    International Nuclear Information System (INIS)

    Colak, Ue.

    2001-01-01

    Safety assessment of nuclear reactors is carried out by simulating the events to taking place in nuclear reactors by realistic computer codes. Such codes are developed in a way that each event is represented by differential equations derived based on physical laws. Nuclear fuel is an important barrier against radioactive fission gas release. The release of radioactivity to environment is the main concern and this can be avoided by preserving the integrity of fuel rod. Therefore, safety analyses should cover an assessment of fuel rod behavior with certain extent. In this study, common approaches for fuel behavior modeling are discussed. Methods utilized by widely accepted computer codes are reviewed. Shortcomings of these methods are explained. Current research topics to improve code reliability and problems encountered in fuel rod behavior modeling are presented

  2. The Current State of Nanoparticle-Induced Macrophage Polarization and Reprogramming Research

    Directory of Open Access Journals (Sweden)

    Xiaoyuan Miao

    2017-02-01

    Full Text Available Macrophages are vital regulators of the host defense in organisms. In response to different local microenvironments, resting macrophages (M0 can be polarized into different phenotypes, pro-inflammatory (M1 or anti-inflammatory (M2, and perform different roles in different physiological or pathological conditions. Polarized macrophages can also be further reprogrammed by reversing their phenotype according to the changed milieu. Macrophage polarization and reprogramming play essential roles in maintaining the steady state of the immune system and are involved in the processes of many diseases. As foreign substances, nanoparticles (NPs mainly target macrophages after entering the body. NPs can perturb the polarization and reprogramming of macrophages, affect their immunological function and, therefore, affect the pathological process of disease. Optimally-designed NPs for the modulation of macrophage polarization and reprogramming might provide new solutions for treating diseases. Systematically investigating how NPs affect macrophage polarization is crucial for understanding the regulatory effects of NPs on immune cells in vivo. In this review, macrophage polarization by NPs is summarized and discussed.

  3. Magnetic field behavior of current steps in long Josephson junctions

    International Nuclear Information System (INIS)

    Costabile, G.; Cucolo, A.M.; Pace, S.; Parmentier, R.D.; Savo, B.; Vaglio, R.

    1980-01-01

    The zero-field steps, or dc current singularities, in the current-voltage characteristics of long Josephson tunnel junctions, first reported by Chen et al., continue to attract research interest both because their study can provide fundamental information on the dynamics of fluxons in such junctions and because they are accompanied by the emission of microwave radiation from the junction, which may be exploitable in practical oscillator applications. The purpose of this paper is to report some experimental observations of the magnetic field behavior of the steps in junctions fabricated in our Laboratory and to offer a qualitative explanation for this behavior. Measurements have been made both for very long (L >> lambdasub(J)) and for slightly long (L approx. >= lambdasub(J)) junctions with a view toward comparing our results with those of other workers. (orig./WRI)

  4. Behavior symposium Workshop A report - current guidelines/revision.

    Science.gov (United States)

    McWhorter, Alton G; Townsend, Janice A

    2014-01-01

    A Workshop of attendees was convened following the completion of the American Academy of Pediatric Dentistry (AAPD) symposium, "Beyond the Guidelines: Factors Affecting Behavior Guidance." The title of Workshop A was Guidelines/Revisions and charges were to review whether the current AAPD Behavior Management Guidelines were adequate to guide delivery of dental care for children with specific attention to their effectiveness and safety, the protection of the pediatric patient and dentist, and the newly revised Protective Stabilization guideline, considering the presentations during the symposium. Major themes emerged as areas for consideration in future revisions of the guidelines: 1) toxic stress and the culture of poverty; 2) behavior risk assessment; 3) contemporary knowledge of pain theory; 4) deferred treatment; 5) parental presence in the operatory and 6) current use of protective stabilization. These issues were examined in the context of the current economic, social, and political environment. A summary of the topics and discussions that took place regarding the adequacy of the guidelines is presented.

  5. Get real: how current behavior influences perceptions of realism and behavioral intent for public service announcements.

    Science.gov (United States)

    Nelson, Michelle R; Zhu, Xuan; Li, Yingying; Fiese, Barbara; Koester, Brenda

    2015-01-01

    This research examined how realism and current behavior influence message reception and processing for public service announcements (PSAs) designed to help parents with meal planning. Findings from 19 in-depth interviews revealed that the perceived realism of the message, the similarity, and the wishful identification with informants' lives influenced message acceptance, in line with the Message Interpretation Process (MIP) model. Results of an online survey with mothers show that realism matters more for those individuals who already engage in the featured behavior. In line with theory, "experts" (meal planners) show increased behavioral intent of the featured behaviors when viewing the more realistic PSA.

  6. Search for the existence of circulating currents in high-Tc superconductors using the polarized neutron scattering technique

    International Nuclear Information System (INIS)

    Sidis, Y.; Fauque, B.; Aji, V.; Bourges, P.

    2007-01-01

    We review experimental attempts using polarized neutron scattering technique to reveal the existence in high temperature superconductors of a long-range ordered state characterized by the spontaneous appearance of current loops. We draw particular attention to our recent results (B. Fauque et al., Phys. Rev. Lett. 96 (2006) 197001) that, up to now, can be explained only by the theory of circulating currents proposed by Varma

  7. Media polarity and concentration roles on the third order nonlinear behaviors of thiazine dyes

    Science.gov (United States)

    Khadem Sadigh, M.; Zakerhamidi, M. S.

    2018-03-01

    Nonlinear optical materials play important roles in optics and photonics. In order to improve the performance of these materials, in this paper, we tried to find effective methods for controlling the nonlinear responses of thiazine dyes. Our experimental results indicate that molecular linear properties, media polarity, concentration and excitation beam properties with different contributions play significant roles on the saturable and reverse saturable absorption characteristics of thiazine dyes. In real, competition between these effective parameters leads to appearance of various third order nonlinear responses. Although by excitation wavelengths near the absorption peaks and at high powers, dye molecules tend to indicate reverse saturable absorption characteristics in polar protic solvents by increasing the concentration, saturable absorption characteristics were observed in polar aprotic solvents. Furthermore, the samples displayed the same behaviors in different solvent media at low powers and for excitation wavelengths far from absorption peaks. Therefore, by controlling the nonlinear responses of thiazine dyes, these materials can indicate both saturable and reverse saturable absorption characteristics that increase their applications in optics and photonics devices.

  8. Determination of the polarity of carrier traps in γ-irradiated polyethylene by temperature gradient thermally stimulated current

    International Nuclear Information System (INIS)

    Kato, Keizo; Iwamoto, Mitsumasa; Hino, Taro

    1986-01-01

    Theoretical analysis is made to show that the polarity of carrier traps produced by radiation can be determined based on measurements of temperature gradient thremally stimulated current. Observations are also made on γ-irradiated polyethylene to examine the polarity of carrier traps. Another investigation is conducted to determine whether a space-charge field is generated in the γ-irradiated polyethylene. In the apparatus used, a collecting voltage is applied to a γ-irradiated specimen to heat it under a temperature gradient while the current generated in an enternal circuit is measured. Theoretical examination, conducted concerning this temperature gradient thermally stimulated current, shows that polarity determination is possible under some conditions. Then, observation is actually carried out using γ-irradiated low-density polyethylene films with deposited gold electrodes. Characteristics of initial rise in thermally stimulated current and effects of the collecting voltage are examined. The polyethylene investigated shows a maximum in thermally stimulated current at about 80 deg C, which is found to have relations with electron traps. It is also revealed that space-charge field is not generated in the sample examined. (Nogami, K.)

  9. Dusty space plasma diagnosis using temporal behavior of polar mesospheric summer echoes during active modification

    Directory of Open Access Journals (Sweden)

    A. Mahmoudian

    2011-11-01

    Full Text Available The objective of this paper is to study the effect of different plasma and dust parameters on Polar Mesospheric Summer Echoes (PMSE temporal behavior after turn-on and turn-off of radio wave heating and to use these responses to diagnose the properties of the dust layer. The threshold radar frequency and dust parameters for the enhancement or suppression of radar echoes after radio wave heating turn-on are investigated for measured mesospheric plasma parameters. The effect of parameters such as the electron temperature enhancement during heating, dust density, dust charge polarity, ion-neutral collision frequency, electron density and dust radius on the temporal evolution of electron irregularities associated with PMSE are investigated. The possible diagnostic information for various charged dust and background plasma quantities using the temporal behavior of backscattered radar power in active experiments is discussed. The computational results are used to make predictions for PMSE active modification experiments at 7.9, 56, 139, 224 and 930 MHz corresponding to existing radar facilities. Data from a 2009 VHF (224 MHz experiment at EISCAT is compared with the computational model to obtain dust parameters in the PMSE.

  10. Spin polarization of tunneling current in barriers with spin-orbit coupling.

    Science.gov (United States)

    Fujita, T; Jalil, M B A; Tan, S G

    2008-03-19

    We present a general method for evaluating the maximum transmitted spin polarization and optimal spin axis for an arbitrary spin-orbit coupling (SOC) barrier system, in which the spins lie in the azimuthal plane and finite spin polarization is achieved by wavevector filtering of electrons. Besides momentum filtering, another prerequisite for finite spin polarization is asymmetric occupation or transmission probabilities of the eigenstates of the SOC Hamiltonian. This is achieved most efficiently by resonant tunneling through multiple SOC barriers. We apply our analysis to common SOC mechanisms in semiconductors: pure bulk Dresselhaus SOC, heterostructures with mixed Dresselhaus and Rashba SOC and strain-induced SOC. In particular, we find that the interplay between Dresselhaus and Rashba SOC effects can yield several advantageous features for spin filter and spin injector functions, such as increased robustness to wavevector spread of electrons.

  11. Spin polarization of tunneling current in barriers with spin-orbit coupling

    International Nuclear Information System (INIS)

    Fujita, T; Jalil, M B A; Tan, S G

    2008-01-01

    We present a general method for evaluating the maximum transmitted spin polarization and optimal spin axis for an arbitrary spin-orbit coupling (SOC) barrier system, in which the spins lie in the azimuthal plane and finite spin polarization is achieved by wavevector filtering of electrons. Besides momentum filtering, another prerequisite for finite spin polarization is asymmetric occupation or transmission probabilities of the eigenstates of the SOC Hamiltonian. This is achieved most efficiently by resonant tunneling through multiple SOC barriers. We apply our analysis to common SOC mechanisms in semiconductors: pure bulk Dresselhaus SOC, heterostructures with mixed Dresselhaus and Rashba SOC and strain-induced SOC. In particular, we find that the interplay between Dresselhaus and Rashba SOC effects can yield several advantageous features for spin filter and spin injector functions, such as increased robustness to wavevector spread of electrons

  12. Optimization of the polarized Klein tunneling currents in a sub-lattice: pseudo-spin filters and latticetronics in graphene ribbons.

    Science.gov (United States)

    López, Luis I A; Yaro, Simeón Moisés; Champi, A; Ujevic, Sebastian; Mendoza, Michel

    2014-02-12

    We found that with an increase of the potential barrier applied to metallic graphene ribbons, the Klein tunneling current decreases until it is totally destroyed and the pseudo-spin polarization increases until it reaches its maximum value when the current is zero. This inverse relation disfavors the generation of polarized currents in a sub-lattice. In this work we discuss the pseudo-spin control (polarization and inversion) of the Klein tunneling currents, as well as the optimization of these polarized currents in a sub-lattice, using potential barriers in metallic graphene ribbons. Using density of states maps, conductance results, and pseudo-spin polarization information (all of them as a function of the energy V and width of the barrier L), we found (V, L) intervals in which the polarized currents in a given sub-lattice are maximized. We also built parallel and series configurations with these barriers in order to further optimize the polarized currents. A systematic study of these maps and barrier configurations shows that the parallel configurations are good candidates for optimization of the polarized tunneling currents through the sub-lattice. Furthermore, we discuss the possibility of using an electrostatic potential as (i) a pseudo-spin filter or (ii) a pseudo-spin inversion manipulator, i.e. a possible latticetronic of electronic currents through metallic graphene ribbons. The results of this work can be extended to graphene nanostructures.

  13. Organizational leadership: motives and behaviors of leaders in current organizations.

    Science.gov (United States)

    Martí, Margarita; Gil, Francisco; Barrasa, Angel

    2009-05-01

    Organizational leadership is fundamental for the working and development of current organizations. It helps members of an organization to face transcendental challenges. One of the fundamental aspects of leaders is their personal characteristics and behaviour as perceived by their co-workers. Although research has established a relationship between these components, findings have failed to come up with any congruent evidence and further to this the organizations and contexts used are from several decades ago. This article, which forms part of the international GLOBE project, analyses the relationship between motives and behaviour as perceived by co-workers in organizations, using quantitative and qualitative methods and including technological innovations. Using samples from 40 corporate directors and 84 of their co-workers, from different companies, it confirms how the main motives of leaders (power, affiliation and achievement) are related to different behavioral patterns (power to authoritarian, non-dependent and non-social-skill behaviours; affiliation to relationship and dependent behaviors, and achievement to proactive behaviors). It discusses the results with relation to traditional research and suggests practical measures and proposals for future investigations in this area.

  14. Period-doubling bifurcation cascade observed in a ferromagnetic nanoparticle under the action of a spin-polarized current

    Energy Technology Data Exchange (ETDEWEB)

    Horley, Paul P., E-mail: paul.horley@cimav.edu.mx [Centro de Investigación en Materiales Avanzados, S.C. (CIMAV), Chihuahua/Monterrey, 120 Avenida Miguel de Cervantes, 31109 Chihuahua (Mexico); Kushnir, Mykola Ya. [Yuri Fedkovych Chernivtsi National University, 2 Kotsyubynsky str., 58012 Chernivtsi (Ukraine); Morales-Meza, Mishel [Centro de Investigación en Materiales Avanzados, S.C. (CIMAV), Chihuahua/Monterrey, 120 Avenida Miguel de Cervantes, 31109 Chihuahua (Mexico); Sukhov, Alexander [Institut für Physik, Martin-Luther Universität Halle-Wittenberg, 06120 Halle (Saale) (Germany); Rusyn, Volodymyr [Yuri Fedkovych Chernivtsi National University, 2 Kotsyubynsky str., 58012 Chernivtsi (Ukraine)

    2016-04-01

    We report on complex magnetization dynamics in a forced spin valve oscillator subjected to a varying magnetic field and a constant spin-polarized current. The transition from periodic to chaotic magnetic motion was illustrated with bifurcation diagrams and Hausdorff dimension – the methods developed for dissipative self-organizing systems. It was shown that bifurcation cascades can be obtained either by tuning the injected spin-polarized current or by changing the magnitude of applied magnetic field. The order–chaos transition in magnetization dynamics can be also directly observed from the hysteresis curves. The resulting complex oscillations are useful for development of spin-valve devices operating in harmonic and chaotic modes.

  15. Pediatric multiple sclerosis: current perspectives on health behaviors

    Directory of Open Access Journals (Sweden)

    Sikes EM

    2018-03-01

    . Discussion: Participation in health behaviors, particularly physical activity, diet, and sleep, may have benefits for POMS. Nevertheless, there are currently no interventions targeting promotion of these behaviors and examining the benefits of managing the primary and secondary manifestations of POMS. Keywords: POMS, health promotion, physical activity, diet, sleep

  16. Modeling interface shear behavior of granular materials using micro-polar continuum approach

    Science.gov (United States)

    Ebrahimian, Babak; Noorzad, Ali; Alsaleh, Mustafa I.

    2018-01-01

    Recently, the authors have focused on the shear behavior of interface between granular soil body and very rough surface of moving bounding structure. For this purpose, they have used finite element method and a micro-polar elasto-plastic continuum model. They have shown that the boundary conditions assumed along the interface have strong influences on the soil behavior. While in the previous studies, only very rough bounding interfaces have been taken into account, the present investigation focuses on the rough, medium rough and relatively smooth interfaces. In this regard, plane monotonic shearing of an infinite extended narrow granular soil layer is simulated under constant vertical pressure and free dilatancy. The soil layer is located between two parallel rigid boundaries of different surface roughness values. Particular attention is paid to the effect of surface roughness of top and bottom boundaries on the shear behavior of granular soil layer. It is shown that the interaction between roughness of bounding structure surface and the rotation resistance of bounding grains can be modeled in a reasonable manner through considered Cosserat boundary conditions. The influence of surface roughness is investigated on the soil shear strength mobilized along the interface as well as on the location and evolution of shear localization formed within the layer. The obtained numerical results have been qualitatively compared with experimental observations as well as DEM simulations, and acceptable agreement is shown.

  17. Zebrafish models of non-canonical Wnt/planar cell polarity signalling: fishing for valuable insight into vertebrate polarized cell behavior.

    Science.gov (United States)

    Jussila, Maria; Ciruna, Brian

    2017-05-01

    Planar cell polarity (PCP) coordinates the uniform orientation, structure and movement of cells within the plane of a tissue or organ system. It is beautifully illustrated in the polarized arrangement of bristles and hairs that project from specialized cell surfaces of the insect abdomen and wings, and pioneering genetic studies using the fruit fly, Drosophila melanogaster, have defined a core signalling network underlying PCP. This core PCP/non-canonical Wnt signalling pathway is evolutionarily conserved, and studies in zebrafish have helped transform our understanding of PCP from a peculiarity of polarized epithelia to a more universal cellular property that orchestrates a diverse suite of polarized cell behaviors that are required for normal vertebrate development. Furthermore, application of powerful genetics, embryonic cell-transplantation, and live-imaging capabilities afforded by the zebrafish model have yielded novel insights into the establishment and maintenance of vertebrate PCP, over the course of complex and dynamic morphogenetic events like gastrulation and neural tube morphogenesis. Although key questions regarding vertebrate PCP remain, with the emergence of new genome-editing technologies and the promise of endogenous labeling and Cre/LoxP conditional targeting strategies, zebrafish remains poised to deliver fundamental new insights into the function and molecular dynamic regulation of PCP signalling from embryonic development through to late-onset phenotypes and adult disease states. WIREs Dev Biol 2017, 6:e267. doi: 10.1002/wdev.267 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.

  18. Polarization Effects in Graded AlGaN Nanolayers Revealed by Current-Sensing and Kelvin Probe Microscopy.

    Science.gov (United States)

    Lytvyn, Petro M; Kuchuk, Andrian V; Mazur, Yuriy I; Li, Chen; Ware, Morgan E; Wang, Zhiming M; Kladko, Vasyl P; Belyaev, Alexander E; Salamo, Gregory J

    2018-02-21

    We experimentally demonstrate that the conductivity of graded Al x Ga 1-x N increases as a function of the magnitude of the Al concentration gradient (%Al/nm) due to polarization doping effects, without the use of impurity dopants. Using three up/down-graded Al x Ga 1-x N nanolayers with Al gradients ranging from ∼0.16 to ∼0.28%Al/nm combined in one structure, the effects of polarization engineering for localized electric fields and current transport were investigated. Cross-sectional Kelvin probe force microscopy and conductive atomic force microscopy were used to directly probe the electrical properties of the films with spatial resolution along the thickness of the growth. The experimental profiles of the built-in electric fields and the spreading current found in the graded layers are shown to be consistent with simulations of the field distribution as well as of the electron and hole densities. Finally, it was directly observed that for gradients less than 0.28%Al/nm the native n-type donors still limit polarization-induced hole doping, making p-type conductivity still a challenge due to background impurities and defects.

  19. Modelling of electrochemical reactors with bio polar electrodes. Prediction of the current distributions

    International Nuclear Information System (INIS)

    HenquIn, E. R; Bisang, J. M

    2005-01-01

    A simplified mathematical model to calculate the current distributions in bipolar electrochemical reactors is proposed.The current distributions are deduced from a combination of the voltage balance in the reactor with a voltage balance including the electrolyte inlet and outlet.Thus, equations to predict the effect of geometric and operational variables on the current distributions at the electrodes are reported.The parameters acting upon the current distributions were lumped into two dimensionless variables and their effects on the current distributions are discussed.The primary current distributions are obtained as a limiting case.Comparisons between calculated and experimental primary current distributions are reported

  20. Effects of Duty Cycle, Current Frequency, and Current Density on Corrosion Behavior of the Plasma Electrolytic Oxidation Coatings on 6061 Al Alloy in Artificial Seawater

    Science.gov (United States)

    Vakili-Azghandi, Mojtaba; Fattah-alhosseini, Arash

    2017-10-01

    In this study, the effects of duty cycle, current frequency, and current density on corrosion behavior of the plasma electrolytic oxidation (PEO) coatings on 6061 Al alloy in artificial seawater (3.5 wt pct NaCl solution) were investigated. To serve this purpose, the electrical parameters of a unipolar pulsed current were applied during the PEO process on 6061 Al alloy in alkaline silicate electrolyte with and without Al2O3 nanoparticles. The coating morphology and microstructure were characterized by the scanning electron microscopy. The corrosion behavior and electrochemical response of the specimens treated by plasma electrolytic oxidation were analyzed by the electrochemical impedance spectroscopy and the potentiodynamic polarization in artificial seawater. It was found that PEO coatings formed in the presence of Al2O3 nanoparticle had lower porosity and exhibited better corrosion behavior compared with the coatings formed in the absence of Al2O3 nanoparticle in the structure. This can be attributed to the nanoparticles' incorporation and penetration through the PEO coatings. On the other hand, the decrease in the current density and increases in the duty cycle and frequency lead to further reduction of the nanoparticles' incorporation and distribution on the coating surface.

  1. Behavioral medicine in China: history, current status, and future development.

    Science.gov (United States)

    Bai, Bo; Ji, Feng

    2014-08-01

    Behavioral medicine in China has developed quickly in the last three decades. We briefly summarized the history, the main scope and achievements, and the future development of behavioral medicine in China. We did a literature search and discussed with senior scholars in behavioral medicine in China. The concept and main scope of behavioral medicine in China have been developed largely in accordance with the international perspective. Research in behavioral medicine in China significantly contributed to the better understanding of the relationship between various health behavioral factors and psychosomatic disorders and possible mechanisms of this relationship. The following aspects will be the main areas to be further developed in behavioral medicine in China: (1) Basic theories of behavioral medicine and theoretical mechanisms of higher nervous activities in human behavior regulation. (2) Etiology, pathogenesis, and mechanisms of common diseases that are closely related to human lifestyle behaviors. (3) Assessment criteria for unhealthy and disease-related behaviors. (4) Behavioral therapy of psychosomatic disorders, and rehabilitation technologies of disability. (5) Application of major findings from research of behavioral medical science in clinical practice and in health promotion of the whole society. Behavioral medicine in China, as a multidisciplinary subject, plays a relevant role in preventing behavior-related psychosomatic diseases and in promoting health of the public.

  2. Novel Three-Phase Current-Regulated Digital PWM and its Behavioral Analysis

    Science.gov (United States)

    Ohshima, Masaaki; Masada, Eisuke

    With respect to PWM algorithm for a three-phase voltage-source ac/dc power converter various studies have been executed and their results have been published since the analog modulation scheme based on triangular carrier wave was proposed in 1960's. PWM algorithm can be considered the heart of the electronic power conversion. Along with progress and evolution of digital technology gate signals are increasingly requested to be generated directly by digital IC, e.g. MPU, DSP or FPGA/CPLD. The paper analyzes quantitatively the precision of the current controllability of digital PWM taking into account of both the sampling period and the delay time the latter of which is inevitably accompanied by digital procedure. The delay time is pointed out to affect the current error double. In addition the paper derives theoretically the condition for digital PWM to accomplish PPCR (Pulse Polarity Consistency Rule, i.e. the next gate command moves only to the adjacent ones). In so far as the authors know no paper offers the mathematical requirements to execute PPCR taking account of the effect by the delay time with digital PWM. The derived theoretical results are summarized as the digital PWM design criteria for a three-phase PWM converter in order to facilitate practical implementation of the theory, which guarantee the PPCR behavior as well as the quantitative preciseness of the current regulation.

  3. Current sheets with inhomogeneous plasma temperature: Effects of polarization electric field and 2D solutions

    International Nuclear Information System (INIS)

    Catapano, F.; Zimbardo, G.; Artemyev, A. V.; Vasko, I. Y.

    2015-01-01

    We develop current sheet models which allow to regulate the level of plasma temperature and density inhomogeneities across the sheet. These models generalize the classical Harris model via including two current-carrying plasma populations with different temperature and the background plasma not contributing to the current density. The parameters of these plasma populations allow regulating contributions of plasma density and temperature to the pressure balance. A brief comparison with spacecraft observations demonstrates the model applicability for describing the Earth magnetotail current sheet. We also develop a two dimensional (2D) generalization of the proposed model. The interesting effect found for 2D models is the nonmonotonous profile (along the current sheet) of the magnetic field component perpendicular to the current sheet. Possible applications of the model are discussed

  4. Direct current (DC) resistivity and induced polarization (IP) monitoring of active layer dynamics at high temporal resolution

    DEFF Research Database (Denmark)

    Doetsch, Joseph; Ingeman-Nielsen, Thomas; Christiansen, Anders V.

    2015-01-01

    With permafrost thawing and changes in active layer dynamics induced by climate change, interactions between biogeochemical and thermal processes in the ground are of great importance. Here, active layer dynamics have been monitored using direct current (DC) resistivity and induced polarization (IP...... and subsurface temperatures supplemented the DC-IP measurements. A time-lapse DC-IP monitoring system has been acquiring at least six datasets per day on a 42-electrode profile with 0.5. m electrode spacing since July 2013. Remote control of the data acquisition system enables interactive adaptation...

  5. Transcranial Direct Current Stimulation and behavioral models of smoking addiction

    Directory of Open Access Journals (Sweden)

    Paige eFraser

    2012-08-01

    Full Text Available While few studies have applied transcranial direct current stimulation (tDCS to smoking addiction, existing work suggests that the intervention holds promise for altering the complex system by which environmental cues interact with cravings to drive behavior. Imaging and repetitive transcranial magnetic stimulation (rTMS studies suggest that increased dorsolateral prefrontal cortex (DLPFC activation and integrity may be associated with increased resistance to smoking cues. Anodal tDCS of the DLPFC, believed to boost activation, reduces cravings in response to these cues. The finding that noninvasive stimulation modifies cue induced cravings has profound implications for understanding the processes underlying addiction and relapse. TDCS can also be applied to probe mechanisms underlying and supporting nicotine addiction, as was done in a pharmacologic study that applied nicotine, tDCS, and TMS paired associative stimulation to find that stopping nicotine after chronic use induces a reduction in plasticity, causing difficulty in breaking free from association between cues and cravings. This mini-review will place studies that apply tDCS to smokers in the context of research involving the neural substrates of nicotine addiction.

  6. Functional Behavior Assessment in Schools: Current Status and Future Directions

    Science.gov (United States)

    Anderson, Cynthia M.; Rodriguez, Billie Jo; Campbell, Amy

    2015-01-01

    Functional behavior assessment is becoming a commonly used practice in school settings. Accompanying this growth has been an increase in research on functional behavior assessment. We reviewed the extant literature on documenting indirect and direct methods of functional behavior assessment in school settings. To discern best practice guidelines…

  7. 3-D time-domain induced polarization tomography: a new approach based on a source current density formulation

    Science.gov (United States)

    Soueid Ahmed, A.; Revil, A.

    2018-04-01

    Induced polarization (IP) of porous rocks can be associated with a secondary source current density, which is proportional to both the intrinsic chargeability and the primary (applied) current density. This gives the possibility of reformulating the time domain induced polarization (TDIP) problem as a time-dependent self-potential-type problem. This new approach implies a change of strategy regarding data acquisition and inversion, allowing major time savings for both. For inverting TDIP data, we first retrieve the electrical resistivity distribution. Then, we use this electrical resistivity distribution to reconstruct the primary current density during the injection/retrieval of the (primary) current between the current electrodes A and B. The time-lapse secondary source current density distribution is determined given the primary source current density and a distribution of chargeability (forward modelling step). The inverse problem is linear between the secondary voltages (measured at all the electrodes) and the computed secondary source current density. A kernel matrix relating the secondary observed voltages data to the source current density model is computed once (using the electrical conductivity distribution), and then used throughout the inversion process. This recovered source current density model is in turn used to estimate the time-dependent chargeability (normalized voltages) in each cell of the domain of interest. Assuming a Cole-Cole model for simplicity, we can reconstruct the 3-D distributions of the relaxation time τ and the Cole-Cole exponent c by fitting the intrinsic chargeability decay curve to a Cole-Cole relaxation model for each cell. Two simple cases are studied in details to explain this new approach. In the first case, we estimate the Cole-Cole parameters as well as the source current density field from a synthetic TDIP data set. Our approach is successfully able to reveal the presence of the anomaly and to invert its Cole

  8. Sunlight effects on the 3D polar current system determined from low Earth orbit measurements

    DEFF Research Database (Denmark)

    Laundal, Karl M.; Finlay, Chris; Olsen, Nils

    2016-01-01

    analyzed together. In this paper, we present estimates of the average global Birkeland currents and horizontal ionospheric currents from the same set of magnetic field measurements. The magnetic field measurements, from the low Earth orbiting Swarm and CHAMP satellites, are used to co-estimate poloidal...

  9. Polar mesosphere summer echoes (PMSE: Review of observations and current understanding

    Directory of Open Access Journals (Sweden)

    M. Rapp

    2004-01-01

    Full Text Available Polar mesosphere summer echoes (PMSE are very strong radar echoes primarily studied in the VHF wavelength range from altitudes close to the polar summer mesopause. Radar waves are scattered at irregularities in the radar refractive index which at mesopause altitudes is effectively determined by the electron number density. For efficient scatter, the electron number density must reveal structures at the radar half wavelength (Bragg condition for monostatic radars; ~3 m for typical VHF radars. The question how such small scale electron number density structures are created in the mesopause region has been a longstanding open scientific question for almost 30 years. This paper reviews experimental and theoretical milestones on the way to an advanced understanding of PMSE. Based on new experimental results from in situ observations with sounding rockets, ground based observations with radars and lidars, numerical simulations with microphysical models of the life cycle of mesospheric aerosol particles, and theoretical considerations regarding the diffusivity of electrons in the ice loaded complex plasma of the mesopause region, a consistent explanation for the generation of these radar echoes has been developed. The main idea is that mesospheric neutral air turbulence in combination with a significantly reduced electron diffusivity due to the presence of heavy charged ice aerosol particles (radii ~5–50 nm leads to the creation of structures at spatial scales significantly smaller than the inner scale of the neutral gas turbulent velocity field itself. Importantly, owing to their very low diffusivity, the plasma structures acquire a very long lifetime, i.e., 10 min to hours in the presence of particles with radii between 10 and 50 nm. This leads to a temporal decoupling of active neutral air turbulence and the existence of small scale plasma structures and PMSE and thus readily explains observations proving the absence of neutral air turbulence at

  10. Instantaneous current and field structure of a gun-driven spheromak for two gun polarities

    Science.gov (United States)

    Woodruff, S.; Nagata, M.

    2002-12-01

    The instantaneous plasma structure of the SPHEX spheromak is determined here by numerically processing data from insertable Rogowski and magnetic field probes. Data is presented and compared for two modes of gun operation: with the central electrode biased positively and negatively. It is found that while the mean-, or even instantaneous-, field structure would give the impression of a roughly axisymmetric spheromak, the instantaneous current structure does not. Hundred per cent variations in J measured at the magnetic axis can be explained by the rotation of a current filament that has a width equal to half of the radius of the flux-conserving first wall. In positive gun operation, current leaves the filament in the confinement region leading to high wall current there. In negative gun operation, wall current remains low as all injected current returns to the gun through the plasma. The plasma, in either instance, is strongly asymmetric. We discuss evidence for the existence of the current filament in other gun-driven spheromaks and coaxial plasma thrusters.

  11. Spin-polarized supercurrents for spintronics: a review of current progress.

    Science.gov (United States)

    Eschrig, Matthias

    2015-10-01

    During the past 15 years a new field has emerged, which combines superconductivity and spintronics, with the goal to pave a way for new types of devices for applications combining the virtues of both by offering the possibility of long-range spin-polarized supercurrents. Such supercurrents constitute a fruitful basis for the study of fundamental physics as they combine macroscopic quantum coherence with microscopic exchange interactions, spin selectivity, and spin transport. This report follows recent developments in the controlled creation of long-range equal-spin triplet supercurrents in ferromagnets and its contribution to spintronics. The mutual proximity-induced modification of order in superconductor-ferromagnet hybrid structures introduces in a natural way such evasive phenomena as triplet superconductivity, odd-frequency pairing, Fulde-Ferrell-Larkin-Ovchinnikov pairing, long-range equal-spin supercurrents, [Formula: see text]-Josephson junctions, as well as long-range magnetic proximity effects. All these effects were rather exotic before 2000, when improvements in nanofabrication and materials control allowed for a new quality of hybrid structures. Guided by pioneering theoretical studies, experimental progress evolved rapidly, and since 2010 triplet supercurrents are routinely produced and observed. We have entered a new stage of studying new phases of matter previously out of our reach, and of merging the hitherto disparate fields of superconductivity and spintronics to a new research direction: super-spintronics.

  12. Educational Behavior Apps and Wearable Devices: Current Research and Prospects

    Science.gov (United States)

    Lowe, Heather

    2016-01-01

    Dartmouth and MIT have developed educational behavior apps and wearable devices that collect contiguous streams of data from student users. Given the consent of the user, the app collects information about a student's physical activity, sleep patterns, and location to form conjectures about social and academic behavior. These apps have the…

  13. Applied Behavior Analysis: Current Myths in Public Education

    Science.gov (United States)

    Fielding, Cheryl; Lowdermilk, John; Lanier, Lauren L.; Fannin, Abigail G.; Schkade, Jennifer L.; Rose, Chad A.; Simpson, Cynthia G.

    2013-01-01

    The effective use of behavior management strategies and related policies continues to be a debated issue in public education. Despite overwhelming evidence espousing the benefits of the implementation of procedures derived from principles based on the science of applied behavior analysis (ABA), educators often indicate many common misconceptions…

  14. A model of the plasma flow and current in Saturn's polar ionosphere under conditions of strong Dungey cycle driving

    Directory of Open Access Journals (Sweden)

    C. M. Jackman

    2006-05-01

    Full Text Available We propose a simple model of the flow and currents in Saturn's polar ionosphere. This model is motivated by theoretical reasoning, and guided quantitatively by in situ field and flow data from space missions, ground-based IR Doppler measurements, and Hubble Space Telescope images. The flow pattern consists of components which represent (1 plasma sub-corotation in the middle magnetosphere region resulting from plasma pick-up and radial transport from internal sources; (2 the Vasyliunas-cycle of internal plasma mass-loss down the magnetospheric tail at higher latitudes; and (3 the polar Dungey-cycle flow driven by the solar wind interaction. Upstream measurements of the interplanetary magnetic field (IMF indicate the occurrence of both extended low-field rarefaction intervals with essentially negligible Dungey-cycle flow, and few-day high-field compression regions in which the Dungey-cycle voltage peaks at a few hundred kV. Here we model the latter conditions when the Dungey-cycle is active, advancing on previous axi-symmetric models which may be more directly applicable to quiet conditions. For theoretical convenience the overall flow pattern is constructed by adding together two components - a purely rotational flow similar to previous axi-symmetric models, and a sun-aligned twin vortex representing the dawn-dusk asymmetry effects associated with the Vasyliunas-and Dungey-cycle flows. We calculate the horizontal ionospheric current associated with the flow and the field-aligned current from its divergence. These calculations show that a sheet of upward-directed field-aligned current flows at the boundary of open field lines which is strongly modulated in local-time by the Dungey-cycle flows. We then consider implications of the field-aligned current for magnetospheric electron acceleration and aurorae using two plasma source populations (hot outer magnetospheric electrons and cool dense magnetosheath electrons. Both sources display a strong dawn

  15. Current density and polarization curves for radial flow field patterns applied to PEMFCs (Proton Exchange Membrane Fuel Cells)

    International Nuclear Information System (INIS)

    Cano-Andrade, S.; Hernandez-Guerrero, A.; Spakovsky, M.R. von; Damian-Ascencio, C.E.; Rubio-Arana, J.C.

    2010-01-01

    A numerical solution of the current density and velocity fields of a 3-D PEM radial configuration fuel cell is presented. The energy, momentum and electrochemical equations are solved using a computational fluid dynamics (CFD) code based on a finite volume scheme. There are three cases of principal interest for this radial model: four channels, eight channels and twelve channels placed in a symmetrical path over the flow field plate. The figures for the current-voltage curves for the three models proposed are presented, and the main factors that affect the behavior of each of the curves are discussed. Velocity contours are presented for the three different models, showing how the fuel cell behavior is affected by the velocity variations in the radial configuration. All these results are presented for the case of high relative humidity. The favorable results obtained for this unconventional geometry seems to indicate that this geometry could replace the conventional commercial geometries currently in use.

  16. Social class and prosocial behavior: current evidence, caveats, and questions.

    Science.gov (United States)

    Piff, Paul K; Robinson, Angela R

    2017-12-01

    This review synthesizes research on social class and prosocial behavior. Individuals of lower social class display increased attention to others and greater sensitivity to others' welfare compared to individuals of higher social class, who exhibit more self-oriented patterns of social cognition. As a result, lower-class individuals are more likely to engage in other-beneficial prosocial behavior, whereas higher-class individuals are more prone to engage in self-beneficial behavior. Although the extant evidence indicates that higher social class standing may tend to undermine prosocial impulses, we propose that the effects of social class on prosocial behavior may also depend on three crucial factors: motivation, identity, and inequality. We discuss how and why these factors may moderate class differences in prosociality and offer promising lines of inquiry for future research. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Direct electric current modifies important cellular aspects and ultrastructure features of Candida albicans yeasts: Influence of doses and polarities.

    Science.gov (United States)

    Barbosa, Gleyce Moreno; Dos Santos, Eldio Gonçalves; Capella, Francielle Neves Carvalho; Homsani, Fortune; de Pointis Marçal, Carina; Dos Santos Valle, Roberta; de Araújo Abi-Chacra, Érika; Braga-Silva, Lys Adriana; de Oliveira Sales, Marcelo Henrique; da Silva Neto, Inácio Domingos; da Veiga, Venicio Feo; Dos Santos, André Luis Souza; Holandino, Carla

    2017-02-01

    Available treatments against human fungal pathogens present high levels of resistance, motivating the development of new antifungal therapies. In this context, the present work aimed to analyze direct electric current (DC) antifungal action, using an in vitro apparatus equipped with platinum electrodes. Candida albicans yeast cells were submitted to three distinct conditions of DC treatment (anodic flow-AF; electroionic flow-EIF; and cathodic flow-CF), as well as different charges, ranging from 0.03 to 2.40 C. Our results indicated C. albicans presented distinct sensibility depending on the DC intensity and polarity applied. Both the colony-forming unit assay and the cytometry flow with propidium iodide indicated a drastic reduction on cellular viability after AF treatment with 0.15 C, while CF- and EIF-treated cells stayed alive when DC doses were increased up to 2.40 C. Additionally, transmission electron microscopy revealed important ultrastructural alterations in AF-treated yeasts, including cell structure disorganization, ruptures in plasmatic membrane, and cytoplasmic rarefaction. This work emphasizes the importance of physical parameters (polarity and doses) in cellular damage, and brings new evidence for using electrotherapy to treat C. albicans pathology process. Bioelectromagnetics. 38:95-108, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Polarity-specific cortical effects of transcranial direct current stimulation in primary somatosensory cortex of healthy humans

    Directory of Open Access Journals (Sweden)

    Robert eRehmann

    2016-05-01

    Full Text Available Transcranial direct current stimulation (tDCS is a noninvasive stimulation method that has been shown to modulate the excitability of the motor and visual cortices in human subjects in a polarity dependent manner in previous studies. The aim of our study was to investigate whether anodal and cathodal tDCS can also be used to modulate the excitability of the human primary somatosensory cortex (S1. We measured paired-pulse suppression (PPS of somatosensory evoked potentials in 36 right-handed volunteers before and after anodal, cathodal or sham stimulation over the right non-dominant S1. Paired-pulse stimulation of the median nerve was performed at the dominant and non-dominant hand. After anodal tDCS, PPS was reduced in the ipsilateral S1 compared to sham stimulation, indicating an excitatory effect of anodal tDCS. In contrast, PPS in the stimulated left hemisphere was increased after cathodal tDCS, indicating an inhibitory effect of cathodal tDCS. Sham stimulation induced no pre-post differences. Thus, tDCS can be used to modulate the excitability of S1 in polarity-dependent manner, which can be assessed by paired-pulse suppression. An interesting topic for further studies could be the investigation of direct correlations between sensory changes and excitability changes induced by tDCS.

  19. Direct current (DC) resistivity and Induced Polarization (IP) monitoring of active layer dynamics at high temporal resolution

    DEFF Research Database (Denmark)

    Doetsch, J.; Fiandaca, G.; Ingeman-Nielsen, Thomas

    2015-01-01

    With permafrost thawing and changes in active layer dynamics induced by climate change, interactions between biogeochemical and thermal processes in the ground are of great importance. Here, active layer dynamics have been monitored using direct current (DC) resistivity and induced polarization (...... non-intrusively and reliably image freezing patterns and their lateral variation on a 10-100 m scale that is difficult to sample by point measurements.......) measurements at high temporal resolution at a heath tundra site on Disko Island on the west coast of Greenland (69°N). Borehole sediment characteristics and subsurface temperatures supplemented the DC-IP measurements. Data acquired during the freezing period of October 2013 – February 2014 clearly image...... the soil freezing as a strong increase in resistivity. While the freezing horizon generally moves deeper with time, some variations in the freezing depth are observed along the profile. Comparison with depth-specific soil temperature indicates an exponential relationship between resistivity and below-freezing...

  20. Polarity-Specific Transcranial Direct Current Stimulation Disrupts Auditory Pitch Learning

    Directory of Open Access Journals (Sweden)

    Reiko eMatsushita

    2015-05-01

    Full Text Available Transcranial direct current stimulation (tDCS is attracting increasing interest because of its potential for therapeutic use. While its effects have been investigated mainly with motor and visual tasks, less is known in the auditory domain. Past tDCS studies with auditory tasks demonstrated various behavioural outcomes, possibly due to differences in stimulation parameters or task measurements used in each study. Further research using well-validated tasks are therefore required for clarification of behavioural effects of tDCS on the auditory system. Here, we took advantage of findings from a prior functional magnetic resonance imaging study, which demonstrated that the right auditory cortex is modulated during fine-grained pitch learning of microtonal melodic patterns. Targeting the right auditory cortex with tDCS using this same task thus allowed us to test the hypothesis that this region is causally involved in pitch learning. Participants in the current study were trained for three days while we measured pitch discrimination thresholds using microtonal melodies on each day using a psychophysical staircase procedure. We administered anodal, cathodal, or sham tDCS to three groups of participants over the right auditory cortex on the second day of training during performance of the task. Both the sham and the cathodal groups showed the expected significant learning effect (decreased pitch threshold over the three days of training; in contrast we observed a blocking effect of anodal tDCS on auditory pitch learning, such that this group showed no significant change in thresholds over the three days. The results support a causal role for the right auditory cortex in pitch discrimination learning.

  1. [Suicide and suicidal behaviors in Mexico: Retrospective and current status].

    Science.gov (United States)

    Borges, Guilherme; Orozco, Ricardo; Benjet, Corina; Medina-Mora, Maria Elena

    2010-01-01

    To summarize the epidemiology of completed suicide and suicidal behavior in Mexico. National data registries on mortality from the year 1970 to 2007 and cross-sectional surveys were used to analyze suicide mortality and suicidal behavior. The suicide rate grew 275% from 1970 to 2007. Suicide has been increasing among Mexicans 15-29 years old since 1970. In adults aged 18-29 years the lifetime prevalence of ideation was 9.7%, and attempt 3.8%. About 6,601,210 Mexicans had suicidal thoughts, 593,600 attempted suicide and 99,731 used some sort of medical service as a direct consequence of the latter in the year prior to the survey. Suicide and suicide-related behaviors are significant public health problems and, as such, actions are urgently required to identify and treat persons with suicidal thoughts, assess suicidal risk in patients with psychiatric disorders and implement population interventions.

  2. Functional characterisation of letter-specific responses in time, space and current polarity using magnetoencephalography.

    Science.gov (United States)

    Gwilliams, L; Lewis, G A; Marantz, A

    2016-05-15

    Recent neurophysiological evidence suggests that a hierarchical neural network of low-to-high level processing subserves written language comprehension. While a considerable amount of research has identified distinct regions and stages of processing, the relations between them and to this hierarchical model remain unclear. Magnetoencephalography (MEG) is a technique frequently employed in such investigations; however, no studies have sought to test whether the conventional method of reconstructing currents at the source of the magnetic field is best suited for such across-subject designs. The present study details the results of three MEG experiments addressing these issues. Neuronal populations supporting responses to low-level orthographic properties were housed posteriorly near the primary visual cortex. More anterior regions along the fusiform gyrus encoded higher-level processes and became active ~80ms later. A functional localiser of these early letter-specific responses was developed for the production of functional regions of interest in future studies. Previously established response components were successfully grouped based on proximity to the localiser, which characterised location, latency and functional sensitivity. Unconventional anatomically constrained signed minimum norm estimates of MEG data were most sensitive to the primary experimental manipulation, suggesting that the conventional unsigned unconstrained method is sub-optimal for studying written word processing. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Taking Sides: An Integrative Review of the Impact of Laterality and Polarity on Efficacy of Therapeutic Transcranial Direct Current Stimulation for Anomia in Chronic Poststroke Aphasia

    Science.gov (United States)

    Sandars, Margaret; Cloutman, Lauren; Woollams, Anna M.

    2016-01-01

    Anomia is a frequent and persistent symptom of poststroke aphasia, resulting from damage to areas of the brain involved in language production. Cortical neuroplasticity plays a significant role in language recovery following stroke and can be facilitated by behavioral speech and language therapy. Recent research suggests that complementing therapy with neurostimulation techniques may enhance functional gains, even amongst those with chronic aphasia. The current review focuses on the use of transcranial Direct Current Stimulation (tDCS) as an adjunct to naming therapy for individuals with chronic poststroke aphasia. Our survey of the literature indicates that combining therapy with anodal (excitatory) stimulation to the left hemisphere and/or cathodal (inhibitory) stimulation to the right hemisphere can increase both naming accuracy and speed when compared to the effects of therapy alone. However, the benefits of tDCS as a complement to therapy have not been yet systematically investigated with respect to site and polarity of stimulation. Recommendations for future research to help determine optimal protocols for combined therapy and tDCS are outlined. PMID:26819777

  4. Taking Sides: An Integrative Review of the Impact of Laterality and Polarity on Efficacy of Therapeutic Transcranial Direct Current Stimulation for Anomia in Chronic Poststroke Aphasia

    Directory of Open Access Journals (Sweden)

    Margaret Sandars

    2016-01-01

    Full Text Available Anomia is a frequent and persistent symptom of poststroke aphasia, resulting from damage to areas of the brain involved in language production. Cortical neuroplasticity plays a significant role in language recovery following stroke and can be facilitated by behavioral speech and language therapy. Recent research suggests that complementing therapy with neurostimulation techniques may enhance functional gains, even amongst those with chronic aphasia. The current review focuses on the use of transcranial Direct Current Stimulation (tDCS as an adjunct to naming therapy for individuals with chronic poststroke aphasia. Our survey of the literature indicates that combining therapy with anodal (excitatory stimulation to the left hemisphere and/or cathodal (inhibitory stimulation to the right hemisphere can increase both naming accuracy and speed when compared to the effects of therapy alone. However, the benefits of tDCS as a complement to therapy have not been yet systematically investigated with respect to site and polarity of stimulation. Recommendations for future research to help determine optimal protocols for combined therapy and tDCS are outlined.

  5. A STUDY OF BROADBAND FARADAY ROTATION AND POLARIZATION BEHAVIOR OVER 1.3–10 GHz IN 36 DISCRETE RADIO SOURCES

    International Nuclear Information System (INIS)

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J.

    2016-01-01

    We present a broadband polarization analysis of 36 discrete polarized radio sources over a very broad, densely sampled frequency band. Our sample was selected on the basis of polarization behavior apparent in narrowband archival data at 1.4 GHz: half the sample shows complicated frequency-dependent polarization behavior (i.e., Faraday complexity) at these frequencies, while half shows comparatively simple behavior (i.e., they appear Faraday simple ). We re-observed the sample using the Australia Telescope Compact Array in full polarization, with 6 GHz of densely sampled frequency coverage spanning 1.3–10 GHz. We have devised a general polarization modeling technique that allows us to identify multiple polarized emission components in a source, and to characterize their properties. We detect Faraday complex behavior in almost every source in our sample. Several sources exhibit particularly remarkable polarization behavior. By comparing our new and archival data, we have identified temporal variability in the broadband integrated polarization spectra of some sources. In a number of cases, the characteristics of the polarized emission components, including the range of Faraday depths over which they emit, their temporal variability, spectral index, and the linear extent of the source, allow us to argue that the spectropolarimetric data encode information about the magneto-ionic environment of active galactic nuclei themselves. Furthermore, the data place direct constraints on the geometry and magneto-ionic structure of this material. We discuss the consequences of restricted frequency bands on the detection and interpretation of polarization structures, and the implications for upcoming spectropolarimetric surveys.

  6. Growth behavior of GaN film along non-polar [1 1 -2 0] directions

    International Nuclear Information System (INIS)

    Gong Xiaojing; Xu Ke; Wang Jianfeng; Yang Hui; Bian Lifeng; Zhang Jingping; Xu Zijian

    2011-01-01

    We studied the atomic assembly mechanisms of non-polar GaN films by the molecular dynamics method as a function of the N:Ga flux ratio at a fixed adatom energy on non-polar planes. Our study revealed that high quality crystal growth occurred only when off-lattice atoms (which are usually associated with amorphous embryos or defect complexes) formed during deposition were able to move to unoccupied lattice sites by thermally activated diffusion processes, which attests to the experimental difficulties in obtaining smooth surfaces due to dense stacking faults lying in non-polar GaN. Furthermore, surface structures on different planes played an important role. We further suggested favorable conditions for growing high quality GaN films and nano-structures along non-polar directions.

  7. Identifications of the polar cap boundary and the auroral belt in the high-altitude magnetosphere: a model for field-aligned currents

    International Nuclear Information System (INIS)

    Sugiura, M.

    1975-01-01

    By means of the Ogo 5 Goddard Space Flight Center fluxgate magnetometer data the polar cap boundary is identified in the high-altitude magnetosphere by a sudden transition from a dipolar field to a more taillike configuration. It is inferred that there exists a field-aligned-current layer at the polar cap boundary. In the night side magnetosphere the polar cap boundary is identified as the high-latitude boundary of the plasma sheet. The field-aligned current flows downward to the ionosphere on the morning side of the magnetosphere and upward from the ionosphere on the afternoon side. The basic pattern of the magnetic field variations observed during the satellite's traversal of the auroral belt is presented. Currents flow in opposite directions in the two field-aligned-current layers. The current directions in these layers as observed by Ogo 5 in the high-altitude magnetosphere are the same as those observed at low altitudes by the polar-orbiting Triad satellite (Armstrong and Zmuda, 1973). The magnetic field in the region where the lower-latitude field-aligned-current layer is situated is essentially meridional. A model is presented in which two field-aligned-current systems, one at the polar cap boundary and the other on the low-latitude part of the auroral belt, are main []y connected by ionospheric currents flowing across the auroral belt. The existence of field-aligned currents deduced from the Ogo 5 observations is a permanent feature of the magnetosphere. Intensifications of the field-aligned currents and occurrences of multiple pairs of field-aligned-current layers characterize the disturbed conditions of these regions

  8. Dialectical Behavior Therapy: Current Indications and Unique Elements

    OpenAIRE

    Chapman, Alexander L.

    2006-01-01

    Dialectical behavior therapy (DBT) is a comprehensive, evidence-based treatment for borderline personality disorder (BPD). The patient populations for which DBT has the most empirical support include parasuicidal women with borderline personality disorder (BPD), but there have been promising findings for patients with BPD and substance use disorders (SUDs), persons who meet criteria for binge-eating disorder, and depressed elderly patients. Although DBT has many similarities with other cognit...

  9. A Measurement of the Effective Electron Neutral Current Coupling Parameters from Polarized Bhabha Scattering at the Z0 Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Langston, Matthew D

    2003-07-15

    The effective electron neutral current coupling parameters, {bar g}{sub V}{sup 3} and {bar g}{sub A}{sup c}, have been measured from analyzing 43,222 polarized Bhabha scattered events (e{sup +}e{sup -} {yields} e{sup +}e{sup -}) using the SLAC Large Detector (SLD) experiment at the Stanford Linear Accelerator Center (SLAC). The SLAC Linear Collider (SLC) produced the Bhabha scattered events by colliding polarized electrons, with an average polarization of 74%, with unpolarized positrons at an average center-of-mass energy of 91.25 GeV. The analysis used the entire SLD data sample collected between 1994 and 1998 (the last year the SLD detector collected data). The results are {bar g}{sub V}{sup e} = -0.0469 {+-} 0.0024 (stat.) {+-} 0.0004 (sys.); {bar g}{sub A}{sup e} = -0.5038 {+-} 0.0010 (stat.) {+-} 0.0043 (sys.). All Bhabha scattered events within the angular acceptance of the SLD calorimeter subsystems were used in this analysis, including both small-angle events (28 mrad. {le} theta {le} 68 mrad.) measured by the Silicon/Tungsten Luminosity Monitor (LUM), and large angle events (0 {le} |cos{theta}| {le} 0.9655) measured by the Liquid Argon Calorimeter (LAC). Using all of the data in this manner allows for the high-precision measurement of the luminosity provided by the LUM to constrain the uncertainty on {bar g}{sub V}{sup e} and {bar g}{sub A}{sup e}. The measured integrated luminosity for the combined 1993 through 1998 SLD data sample is L{sub Integrated} = 19,247 {+-} 17 (stat.) {+-} 146 (sys.) nb{sup -1}. In contrast with other SLD precision measurements of the effective weak mixing angle, which are sensitive to the ratio {bar g}{sub V}{sup e}/{bar g}{sub A}{sup e}, this result independently determines {bar g}{sub V}{sup 3} and {bar g}{sub A}{sup c}. The analysis techniques to measure {bar g}{sub V}{sup 3} and {bar g}{sub A}{sup c} are described, and the results are compared with other SLD measurements as well as other experiments.

  10. Magnetization switching of a metallic nanomagnet via current-induced surface spin-polarization of an underlying topological insulator

    International Nuclear Information System (INIS)

    Roy, Urmimala; Dey, Rik; Pramanik, Tanmoy; Ghosh, Bahniman; Register, Leonard F.; Banerjee, Sanjay K.

    2015-01-01

    We consider a thermally stable, metallic nanoscale ferromagnet (FM) subject to spin-polarized current injection and exchange coupling from the spin-helically locked surface states of a topological insulator (TI) to evaluate possible non-volatile memory applications. We consider parallel transport in the TI and the metallic FM, and focus on the efficiency of magnetization switching as a function of transport between the TI and the FM. Transport is modeled as diffusive in the TI beneath the FM, consistent with the mobility in the TI at room temperature, and in the FM, which essentially serves as a constant potential region albeit spin-dependent except in the low conductivity, diffusive limit. Thus, it can be captured by drift-diffusion simulation, which allows for ready interpretation of the results. We calculate switching time and energy consumed per write operation using self-consistent transport, spin-transfer-torque (STT), and magnetization dynamics calculations. Calculated switching energies and times compare favorably to conventional spin-torque memory schemes for substantial interlayer conductivity. Nevertheless, we find that shunting of current from the TI to a metallic nanomagnet can substantially limit efficiency. Exacerbating the problem, STT from the TI effectively increases the TI resistivity. We show that for optimum performance, the sheet resistivity of the FM layer should be comparable to or larger than that of the TI surface layer. Thus, the effective conductivity of the FM layer becomes a critical design consideration for TI-based non-volatile memory

  11. Sociocultural Behavior Influence Modelling & Assessment: Current Work and Research Frontiers.

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Michael Lewis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-01-01

    A common problem associated with the effort to better assess potential behaviors of various individuals within different countries is the shear difficulty in comprehending the dynamic nature of populations, particularly over time and considering feedback effects. This paper discusses a theory-based analytical capability designed to enable analysts to better assess the influence of events on individuals interacting within a country or region. These events can include changes in policy, man-made or natural disasters, migration, war, or other changes in environmental/economic conditions. In addition, this paper describes potential extensions of this type of research to enable more timely and accurate assessments.

  12. Current Suicide Proneness and Past Suicidal Behavior in Adjudicated Adolescents

    Science.gov (United States)

    Langhinrichsen-Rohling, Jennifer; Lamis, Dorian A.

    2008-01-01

    Youth recently assigned to probation (n = 233) were assessed for current suicide proneness, depression, and hopelessness, as well as for recent suicide ideation, previous suicide ideation, or suicide attempt(s). The Life Attitudes Schedule-Short Form (LAS-SF) was used to assess suicide proneness. As per the LAS-SF, suicide proneness was defined…

  13. Subauroral polarization stream on the outer boundary of the ring current during an energetic ion injection event

    Science.gov (United States)

    Yuan, Zhigang; Qiao, Zheng; Li, Haimeng; Huang, Shiyong; Wang, Dedong; Yu, Xiongdong; Yu, Tao

    2017-04-01

    Subauroral polarization stream (SAPS) electric field can play an important role in the coupling between the inner magnetosphere and ionosphere; however, the production mechanism of SAPS has not been yet solved. During an energetic ion injection event on 26 March 2004, at latitudes lower than the equatorward boundaries of precipitating plasma sheet electrons and ions, the Defense Meteorological Satellite Program (DMSP) F13 satellite simultaneously observed a strong SAPS with the peak velocity of 1294 m/s and downward flowing field-aligned currents (FACs). Conjugate observations of DMSP F13 and NOAA 15 satellites have shown that FACs flowing into the ionosphere just lie in the outer boundary of the ring current (RC). The downward flowing FACs were observed in a region of positive latitudinal gradients of the ion energy density, implying that the downward flowing FACs are more likely linked to the azimuthal gradient than the radial gradient of the RC ion pressure. Our result demonstrates that RC ion pressure gradients on the outer boundary of the RC in the evening sector during energetic ion injection events can lead to downward flowing FACs so as to cause strong SAPS in condition of low ionospheric conductivities.Plain Language SummaryThis paper provides a good case that the SAPS and FAC occurred in the outer boundary of the ring current during an energetic ion injection event. Our result demonstrates that RC ion pressure gradients on the outer boundary of the RC in the evening sector during energetic ion injection events can lead to downward flowing FACs so as to cause strong SAPS in condition of low ionospheric conductivities.

  14. Thermal behavior induced by vacuum polarization on causal horizons in comparison with the standard heat bath formalism

    Energy Technology Data Exchange (ETDEWEB)

    Schroer, Bert [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]|[Institut fuer Theoretische Physik, Berlin (Germany); E-mail schroer@cbpf.br

    2003-02-01

    Modular theory of operator algebras and the associated K MS property are used to obtain a unified description for the thermal aspects of the standard heat bath situation and those caused by quantum vacuum fluctuations from localization. An algebraic variant of light front holography reveals that the vacuum polarization on wedge horizons is compressed into the light ray direction. Their absence in the transverse direction is the prerequisite to an area (generalized Banknotes-) behavior of entropy-like measures which reveal the loss of purity due to restrictions to wedges and their horizons. Besides the well-known fact that localization-induced (generalized Hawking-) temperature is fixed by the geometric aspects, this area behavior (versus the standard volume dependence) constitutes the main difference between localization-caused and standard thermal behavior. (author)

  15. Study of semileptonic and leptonic neutral-current processes and of $\\mu$-polarization using counter techniques

    CERN Multimedia

    2002-01-01

    .PP This experiment will study semileptonic neutral current neutrino interactions with nucleons, using principally the dichromatic neutrino beam N1 and will make measurements of the polarization of muons produced in the WA1 experiment by neutrino-nucleon interactions, using the horn-focused broad-band neutrino The main part of the apparatus is a fine-grained target calorimeter in which the energy and direction of the hadronic jet resulting from the neutrino scattering is measured by electronic techniques. It is supplemented by a muon detector and spectrometer. The fine-grained calorimeter is used as a polarimeter for muons produced in WA1. \\\\ \\\\ The calorimeter is composed of 13 modules, each 1.2 m long and 4~m x 4~m in cross section. A module consists of six 3 m x 3 m target plates made of 8 cm thick marble with 12 cm gaps for insertion of 20 scintillation counters of 15 cm width and 3 cm thickness, 128 proportional counters of 3~x~3~cm|2 cross-section and 4~m length, and 256 streamer tubes of 0.9~x~0.9~cm|2...

  16. Polar conic current sheets as sources and channels of energetic particles in the high-latitude heliosphere

    Science.gov (United States)

    Khabarova, Olga; Malova, Helmi; Kislov, Roman; Zelenyi, Lev; Obridko, Vladimir; Kharshiladze, Alexander; Tokumaru, Munetoshi; Sokół, Justyna; Grzedzielski, Stan; Fujiki, Ken'ichi; Malandraki, Olga

    2017-04-01

    The existence of a large-scale magnetically separated conic region inside the polar coronal hole has been predicted by the Fisk-Parker hybrid heliospheric magnetic field model in the modification of Burger and co-workers (Burger et al., ApJ, 2008). Recently, long-lived conic (or cylindrical) current sheets (CCSs) have been found from Ulysses observations at high heliolatitudes (Khabarova et al., ApJ, 2017). The characteristic scale of these structures is several times lesser than the typical width of coronal holes, and the CCSs can be observed at 2-3 AU for several months. CCS crossings in 1994 and 2007 are characterized by sharp decreases in the solar wind speed and plasma beta typical for predicted profiles of CCSs. In 2007, a CCS was detected directly over the South Pole and strongly highlighted by the interaction with comet McNaught. The finding is confirmed by restorations of solar coronal magnetic field lines that reveal the occurrence of conic-like magnetic separators over the solar poles both in 1994 and 2007. Interplanetary scintillation data analysis also confirms the existence of long-lived low-speed regions surrounded by the typical polar high-speed solar wind in solar minima. The occurrence of long-lived CCSs in the high-latitude solar wind could shed light on how energetic particles reach high latitudes. Energetic particle enhancements up to tens MeV were observed by Ulysses at edges of CCSs both in 1994 and 2007. In 1994 this effect was clearer, probably due to technical reasons. Accelerated particles could be produced either by magnetic reconnection at the edges of a CCS in the solar corona or in the solar wind. We discuss the role of high-latitude CCSs in propagation of energetic particles in the heliosphere and revisit previous studies of energetic particle enhancements at high heliolatitudes. We also suggest that the existence of a CCS can modify the distribution of the solar wind as a function of heliolatitude and consequently impact ionization

  17. Blind Ethics: Closing One's Eyes Polarizes Moral Judgments and Discourages Dishonest Behavior

    Science.gov (United States)

    Caruso, Eugene M.; Gino, Francesca

    2011-01-01

    Four experiments demonstrate that closing one's eyes affects ethical judgment and behavior because it induces people to mentally simulate events more extensively. People who considered situations with their eyes closed rather than open judged immoral behaviors as more unethical and moral behaviors as more ethical. In addition, considering…

  18. Demography and behavior of polar bears summering on land in Alaska

    Science.gov (United States)

    Peacock, Lily

    2014-01-01

    Polar bears (Ursus maritimus) in the southern Beaufort Sea population (SB) are spending increased time on the coastal North Slope of Alaska between July and October (Gleason and Rode 2010). The duration spent on land by polar bears, satellite collared on the sea-ice in the spring, during the summer and fall has also increased (USGS, unpublished data; Figure 1). This change in polar bear ecology has relevance for human-bear interactions, subsistence harvest, prevalence of defense kills, and disturbance associated with existing land-based development [e.g., National Petroleum Reserve of Alaska (NPRA), Arctic National Wildlife Refuge (ANWR)], Native Alaskan communities, recreation (ANWR) and tourism (e.g., bear viewing in Kaktovik, AK). These activities have the potential to impact, in new ways, the status of the entire SB population. Concomitantly, the change in polar bear ecology will impact these human activities, and a base-line characterization of this phenomenon can better inform mitigation (e.g., industry permitting under the Endangered Species Act and Marine Mammal Protection Act). In this study we aim to characterize the demography, habitat-use, and aspects of foraging ecology and health of polar bears spending fall on land. The SB population is characterized by a divergent-sea ice ecology, where polar bears typically spend most of the year on the sea-ice, even as the pack ice retreats northward, away from the coast, to its minimal extent in September (Amstrup et al. 2008; Durner et al. 2009). From 2000 – 2005, using coastal aerial surveys, Schliebe et al. (2008) observed between 3.7 and 8% of polar bears from SB (~ 60 – 120 of 1526, Regher et al. 2006) on land during the autumn. Sighting probability was not estimated in these surveys, and therefore the numbers represent minimum numbers of bears on land. Our analysis of USGS data suggest an annual average of 15% (± 3%, SE) of polar bears satellite-tagged on the spring-time sea ice (total n = 18 of 124

  19. Direct observation of hopping induced spin polarization current in oxygen deficient Co-doped ZnO by Andreev reflection technique

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Kung-Shang; Huang, Tzu-Yu; Dwivedi, G.D. [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Lin, Lu-Kuei; Lee, Shang-Fan [Taiwan Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Sun, Shih-Jye [Department of Applied Physics, National Kaohsiung University, Kaohsiung, Taiwan (China); Chou, Hsiung, E-mail: hchou@mail.nsysu.edu.tw [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

    2017-07-01

    Highlights: • Co-doped ZnO thin-films were grown with varying V{sub O} concentartion. • PCAR measurements were done to study the SPC. • High spin polarization was observed above a certain V{sub O} concentartion. • High V{sub O} samples provide a high density of completed percolation path. • This complete percolation path gives rise to high SPC. - Abstract: Oxygen vacancy induced ferromagnetic coupling in diluted magnetic oxide (DMO) semiconductors have been reported in several studies, but technologically more crucial spin-polarized current (SPC) is still under-developed in DMOs. Few studies have claimed that VRH mechanism can originate the SPC, but, how VRH mechanism associated with percolation path, is not clearly understood. We used Point-contact Andreev reflection (PCAR) technique to probe the SPC in Co-doped ZnO (CZO) films. Since the high resistance samples cause broadening in conductance(G)-voltage(V) curves, which may result in an unreliable evaluation of spin polarization, we include two extra parameters, (i) effective temperature and (ii) spreading resistance, for the simulation to avoid the uncertainty in extracting spin polarization. The effective G-V curves and higher spin polarization can be obtained above a certain oxygen vacancy concentration. The number of completed and fragmentary percolation paths is proportional to the concentration of oxygen vacancies. For low oxygen vacancy samples, the Pb-tip has a higher probability of covering fragmentary percolation paths than the complete ones, due to its small contact size. The completed paths may remain independent of one another and get polarized in different directions, resulting in lower spin-polarization value. High oxygen vacancy samples provide a high density of completed path, most of them link to one another by crossing over, and gives rise to high spin-polarization value.

  20. Some Current Dimensions of the Behavioral Economics of Health-Related Behavior Change

    Science.gov (United States)

    Bickel, Warren K.; Moody, Lara; Higgins, Stephen T.

    2016-01-01

    Health-related behaviors such as tobacco, alcohol and other substance use, poor diet and physical inactivity, and risky sexual practices are important targets for research and intervention. Health-related behaviors are especially pertinent targets in the United States, which lags behind most other developed nations on common markers of population health. In this essay we examine the application of behavioral economics, a scientific discipline that represents the intersection of economics and psychology, to the study and promotion of health-related behavior change. More specifically, we review what we consider to be some core dimensions of this discipline when applied to the study health-related behavior change. Behavioral economics (1) provides novel conceptual systems to inform scientific understanding of health behaviors, (2) translates scientific understanding into practical and effective behavior-change interventions, (3) leverages varied aspects of behavior change beyond increases or decreases in frequency, (4) recognizes and exploits trans-disease processes and interventions, and (5) leverages technology in efforts to maximize efficacy, cost effectiveness, and reach. These dimensions are overviewed and their implications for the future of the field discussed. PMID:27283095

  1. Some current dimensions of the behavioral economics of health-related behavior change.

    Science.gov (United States)

    Bickel, Warren K; Moody, Lara; Higgins, Stephen T

    2016-11-01

    Health-related behaviors such as tobacco, alcohol and other substance use, poor diet and physical inactivity, and risky sexual practices are important targets for research and intervention. Health-related behaviors are especially pertinent targets in the United States, which lags behind most other developed nations on common markers of population health. In this essay we examine the application of behavioral economics, a scientific discipline that represents the intersection of economics and psychology, to the study and promotion of health-related behavior change. More specifically, we review what we consider to be some core dimensions of this discipline when applied to the study health-related behavior change. Behavioral economics (1) provides novel conceptual systems to inform scientific understanding of health behaviors, (2) translates scientific understanding into practical and effective behavior-change interventions, (3) leverages varied aspects of behavior change beyond increases or decreases in frequency, (4) recognizes and exploits trans-disease processes and interventions, and (5) leverages technology in efforts to maximize efficacy, cost effectiveness, and reach. These dimensions are overviewed and their implications for the future of the field discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Improved corrosion behavior of nanocrystalline zinc produced by pulse-current electrodeposition

    International Nuclear Information System (INIS)

    Youssef, Kh.M.S.; Koch, C.C.; Fedkiw, P.S.

    2004-01-01

    Pulse electrodeposition was used to produce nanocrystalline (nc) zinc from zinc chloride electrolyte with polyacrylamide and thiourea as additives. Field emission scanning electron microscopy (FESEM) was used to study the grain size and surface morphology of the deposits and X-ray diffraction was used to examine their preferred orientation. Corrosion behavior of the electrodeposited nc zinc in comparison with electrogalvanized (EG) steel in de-aerated 0.5 N NaOH solution was studied using potentiodynamic polarization and impedance measurements. A scanning electron microscope (SEM) was used to characterize the surface morphology of the EG steel before corrosion testing. Surface morphologies of nc zinc deposits and EG steel were also studied after potentiondynamic polarization by SEM. Nanocrystalline zinc (56 nm) with random orientation was produced. The estimated corrosion rate of nc zinc was found to be about 60% lower than that of EG steel, 90 and 229 μA/cm 2 , respectively. The surface morphology of corroded nc zinc was characterized by discrete etch pits, however, uniform corrosion was obtained after potentiodynamic polarization of EG steel. The passive film formed on the nc zinc surface seems to be a dominating factor for the corrosion behavior observed

  3. Spin-polarized current and shot noise in the presence of spin flip in a quantum dot via nonequilibrium Green's functions

    DEFF Research Database (Denmark)

    De Souza, Fabricio; Jauho, Antti-Pekka; Egues, J.C.

    2008-01-01

    Using nonequilibrium Green's functions we calculate the spin-polarized current and shot noise in a ferromagnet-quantum-dot-ferromagnet system. Both parallel (P) and antiparallel (AP) magnetic configurations are considered. Coulomb interaction and coherent spin flip (similar to a transverse magnet...

  4. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  5. Influence of InAlN Nanospiral Structures on the Behavior of Reflected Light Polarization

    Directory of Open Access Journals (Sweden)

    Yu-Hung Kuo

    2018-03-01

    Full Text Available The influence of structural configurations of indium aluminum nitride (InAlN nanospirals, grown by reactive magnetron sputter epitaxy, on the transformation of light polarization are investigated in terms of varying structural chirality, growth temperatures, titanium nitride (TiN seed (buffer layer thickness, nanospiral thickness, and pitch. The handedness of reflected circularly polarized light in the ultraviolet–visible region corresponding to the chirality of nanospirals is demonstrated. A high degree of circular polarization (Pc value of 0.75 is obtained from a sample consisting of 1.2 μm InAlN nanospirals grown at 650 °C. A film-like structure is formed at temperatures lower than 450 °C. At growth temperatures higher than 750 °C, less than 0.1 In-content is incorporated into the InAlN nanospirals. Both cases reveal very low Pc. A red shift of wavelength at Pc peak is found with increasing nanospiral pitch in the range of 200–300 nm. The Pc decreases to 0.37 for two-turn nanospirals with total length of 0.7 μm, attributed to insufficient constructive interference. A branch-like structure appears on the surface when the nanospirals are grown longer than 1.2 μm, which yields a low Pc around 0.5, caused by the excessive scattering of incident light.

  6. An Internal Polarity Landmark Is Important for Externally Induced Hyphal Behaviors in Candida albicans▿

    Science.gov (United States)

    Brand, Alexandra; Vacharaksa, Anjalee; Bendel, Catherine; Norton, Jennifer; Haynes, Paula; Henry-Stanley, Michelle; Wells, Carol; Ross, Karen; Gow, Neil A. R.; Gale, Cheryl A.

    2008-01-01

    Directional growth is a function of polarized cells such as neurites, pollen tubes, and fungal hyphae. Correct orientation of the extending cell tip depends on signaling pathways and effectors that mediate asymmetric responses to specific environmental cues. In the hyphal form of the eukaryotic fungal pathogen Candida albicans, these responses include thigmotropism and galvanotropism (hyphal turning in response to changes in substrate topography and imposed electrical fields, respectively) and penetration into semisolid substrates. During vegetative growth in C. albicans, as in the model yeast Saccharomyces cerevisiae, the Ras-like GTPase Rsr1 mediates internal cellular cues to position new buds in a prespecified pattern on the mother cell cortex. Here, we demonstrate that Rsr1 is also important for hyphal tip orientation in response to the external environmental cues that induce thigmotropic and galvanotropic growth. In addition, Rsr1 is involved in hyphal interactions with epithelial cells in vitro and its deletion diminishes the hyphal invasion of kidney tissue during systemic infection. Thus, Rsr1, an internal polarity landmark in yeast, is also involved in polarized growth responses to asymmetric environmental signals, a paradigm that is different from that described for the homologous protein in S. cerevisiae. Rsr1 may thereby contribute to the pathogenesis of C. albicans infections by influencing hyphal tip responses triggered by interaction with host tissues. PMID:18281602

  7. An internal polarity landmark is important for externally induced hyphal behaviors in Candida albicans.

    Science.gov (United States)

    Brand, Alexandra; Vacharaksa, Anjalee; Bendel, Catherine; Norton, Jennifer; Haynes, Paula; Henry-Stanley, Michelle; Wells, Carol; Ross, Karen; Gow, Neil A R; Gale, Cheryl A

    2008-04-01

    Directional growth is a function of polarized cells such as neurites, pollen tubes, and fungal hyphae. Correct orientation of the extending cell tip depends on signaling pathways and effectors that mediate asymmetric responses to specific environmental cues. In the hyphal form of the eukaryotic fungal pathogen Candida albicans, these responses include thigmotropism and galvanotropism (hyphal turning in response to changes in substrate topography and imposed electrical fields, respectively) and penetration into semisolid substrates. During vegetative growth in C. albicans, as in the model yeast Saccharomyces cerevisiae, the Ras-like GTPase Rsr1 mediates internal cellular cues to position new buds in a prespecified pattern on the mother cell cortex. Here, we demonstrate that Rsr1 is also important for hyphal tip orientation in response to the external environmental cues that induce thigmotropic and galvanotropic growth. In addition, Rsr1 is involved in hyphal interactions with epithelial cells in vitro and its deletion diminishes the hyphal invasion of kidney tissue during systemic infection. Thus, Rsr1, an internal polarity landmark in yeast, is also involved in polarized growth responses to asymmetric environmental signals, a paradigm that is different from that described for the homologous protein in S. cerevisiae. Rsr1 may thereby contribute to the pathogenesis of C. albicans infections by influencing hyphal tip responses triggered by interaction with host tissues.

  8. Polarization dependent behavior of CdS around the first and second LO-phonon modes

    Energy Technology Data Exchange (ETDEWEB)

    Frausto-Reyes, C., E-mail: cfraus@cio.mx [Centro de Investigaciones en Optica AC, Unidad Aguascalientes, Prolong., Constitucion 607, Fracc. Reserva Loma Bonita, CP 20200, Apartado Postal 507, Ags. (Mexico); Molina-Contreras, J.R., E-mail: rmolina@correo.ita.mx [Departamento de Ingenieria Electrica y Electronica, Instituto Tecnologico de Aguascalientes, Av. Lopez Mateos 1081 Oriente, Fracc. Bonna Gens, CP 20256, Aguascalientes, Ags. (Mexico); Lopez-Alvarez, Y.F. [Departamento de Ingenieria Electrica y Electronica, Instituto Tecnologico de Aguascalientes, Av. Lopez Mateos 1081 Oriente, Fracc. Bonna Gens, CP 20256, Aguascalientes, Ags. (Mexico); Medel-Ruiz, C.I.; Perez Ladron de Guevara, H. [Universidad de Guadalajara, Centro Universitario de los Lagos, Av. Enrique Diaz de Leon s/n, Fracc. Paseos de la Montana, CP 47460, Lagos de Moreno, Jal. (Mexico); Ortiz-Morales, M. [Centro de Investigaciones en Optica AC, Unidad Aguascalientes, Prolong., Constitucion 607, Fracc. Reserva Loma Bonita, CP 20200, Apartado Postal 507, Ags. (Mexico)

    2010-10-25

    The present work report studies on resonant Raman experimental line shape for CdS around the first and second LO-phonon modes. The application of our method to the study of LO-phonon modes of CdS suggests that the scattered intensity is dominated by the surface and dependent on polarization. Results showed that the Raman spectra for CdS, roughly fall into three groups: a broad line-wing with apparent maxima around 194 cm{sup -1} in the range of 140 and 240 cm{sup -1} which can be ascribed to overtone scattering from acoustic phonons; a band near the 1LO phonon mode which can be attributed to a combination of one-phonon scattering and peak acoustic phonon and finally, a band near the 2LO phonon mode which can be attributed to a combination of two-phonon scattering and peak acoustic phonon.

  9. Corrosion Behavior of Surface-Treated Implant Ti-6Al-4V by Electrochemical Polarization and Impedance Studies

    Science.gov (United States)

    Paul, Subir; Yadav, Kasturi

    2011-04-01

    Implant materials for orthopedic and heart surgical services demand a better corrosion resistance material than the presently used titanium alloys, where protective oxide layer breaks down on a prolonged stay in aqueous physiological human body, giving rise to localized corrosion of pitting, crevice, and fretting corrosion. A few surface treatments on Ti alloy, in the form of anodization, passivation, and thermal oxidation, followed by soaking in Hank solution have been found to be very effective in bringing down the corrosion rate as well as producing high corrosion resistance surface film as reflected from electrochemical polarization, cyclic polarization, and Electrochemical Impedance Spectroscopy (EIS) studies. The XRD study revealed the presence of various types of oxides along with anatase and rutile on the surface, giving rise to high corrosion resistance film. While surface treatment of passivation and thermal oxidation could reduce the corrosion rate by 1/5th, anodization in 0.3 M phosphoric acid at 16 V versus stainless steel cathode drastically brought down the corrosion rate by less than ten times. The mechanism of corrosion behavior and formation of different surface films is better understood from the determination of EIS parameters derived from the best-fit equivalent circuit.

  10. Enhanced bipolar resistive switching behavior in polar Cr-doped barium titanate thin films without electro-forming process

    Directory of Open Access Journals (Sweden)

    Atul Thakre

    2017-12-01

    Full Text Available An enhanced, repeatable and robust resistive switching phenomenon was observed in Cr substituted BaTiO3 polar ferroelectric thin films; fabricated and deposited by the sol-gel approach and spin coating technique, respectively. An enhanced bistable bipolar resistive switching (BRS phenomenon without electro-forming process, low switching voltage (∼ 2 V and moderate retention characteristics of 104 s along with a high Roff/Ron resistance ratio ∼103 was achieved. The current conduction analysis showed that the space charge limited conduction (SCLC and Schottky emission conduction dominate in the high voltage range, while thermally active charge carriers (ohmic in the lower voltage range. The impedance spectroscopy study indicates the formation of current conducting path and rupturing of oxygen vacancies during SET and RESET process.

  11. Enhanced bipolar resistive switching behavior in polar Cr-doped barium titanate thin films without electro-forming process

    Science.gov (United States)

    Thakre, Atul; Kumar, Ashok

    2017-12-01

    An enhanced, repeatable and robust resistive switching phenomenon was observed in Cr substituted BaTiO3 polar ferroelectric thin films; fabricated and deposited by the sol-gel approach and spin coating technique, respectively. An enhanced bistable bipolar resistive switching (BRS) phenomenon without electro-forming process, low switching voltage (˜ 2 V) and moderate retention characteristics of 104 s along with a high Roff/Ron resistance ratio ˜103 was achieved. The current conduction analysis showed that the space charge limited conduction (SCLC) and Schottky emission conduction dominate in the high voltage range, while thermally active charge carriers (ohmic) in the lower voltage range. The impedance spectroscopy study indicates the formation of current conducting path and rupturing of oxygen vacancies during SET and RESET process.

  12. Influence of arc current and pressure on non-chemical equilibrium air arc behavior

    Science.gov (United States)

    Yi, WU; Yufei, CUI; Jiawei, DUAN; Hao, SUN; Chunlin, WANG; Chunping, NIU

    2018-01-01

    The influence of arc current and pressure on the non-chemical equilibrium (non-CE) air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavior during both the arc burning and arc decay phases were discussed at different currents and different pressures. We also devised the concept of a non-equilibrium parameter for a better understanding of non-CE effects. During the arc burning phase, the increasing current leads to a decrease of the non-equilibrium parameter of the particles in the arc core, while the increasing pressure leads to an increase of the non-equilibrium parameter of the particles in the arc core. During the arc decay phase, the non-CE effect will decrease by increasing the arc burning current and the nozzle pressure. Three factors together—convection, diffusion and chemical reactions—influence non-CE behavior.

  13. Variables affecting the manifestation of and intensity of pacing behavior: A preliminary case study in zoo-housed polar bears.

    Science.gov (United States)

    Cless, Isabelle T; Lukas, Kristen E

    2017-09-01

    High-speed video analysis was used to quantify two aspects of gait in 10 zoo-housed polar bears. These two variables were then examined as to how they differed in the conditions of pacing versus locomoting for each bear. Percent difference calculations measured the difference between pacing and locomoting data for each bear. We inferred that the higher the percent difference between pacing and locomoting in a given subject, the more intense the pacing may be. The percent difference values were analyzed alongside caregiver survey data defining the locations, frequency, and anticipatory nature of pacing in each bear, as well as each bear's age and sex, to determine whether any variables were correlated. The frequency and intensity of pacing behavior were not correlated. However, location of pacing was significantly correlated both with the subjects' age and whether or not the subject was classified as an anticipatory pacer. Bears appeared to select specific spots within their exhibits to pace, and the location therefore seemed tied to underlying motivation for the behavior. Additionally, bears that were classified in the survey as pacing anticipatorily displayed significantly more intense pacing behavior as quantified by gait analysis. © 2017 Wiley Periodicals, Inc.

  14. Stray current vs anodic polarization in reinforced mortar: a comparative study on steel corrosion behaviour in both regimes

    NARCIS (Netherlands)

    Chen, Zhipei; Koleva, D.A.; van Breugel, K.

    2015-01-01

    Stray current arising from direct current electrified traction systems and then circulat-ing in reinforced concrete structures may initiate corrosion or even accelerate existing corrosion processes on embedded reinforcement. Therefore, stray-current induced corrosion of nearby reinforced concrete

  15. Analyzing Operating Behavior of Hot Mill Table Roll Drives using Statistical Methods for Current Values

    Science.gov (United States)

    Kabakov, P. Z.; Kozhevnikov, A. V.; Ilatovsky, I. S.

    2017-12-01

    The article briefly describes failures of table rolls in Hot Rolling Mill 2000, PAO Severstal, and provides research results obtained by applying statistical methods. The statistical analysis showed a possibility of detecting deviations in roll behavior based on electric drive current changes, which cause failures. The statistical data analysis was employed to define roll critical behavior, which is to be checked using additional data. For this purpose, the research will be continued, roll operating behavior will be studied during the entire lifetime with due regard for deviations detected, comprehensive statistical analysis will be carried out, influence of rolling mill practices and roll failure predictability will be assessed.

  16. Effects of polar field-aligned currents on the distribution of the electric field and current in the middle and low latitudes ionosphere

    International Nuclear Information System (INIS)

    Maekawa, Koichiro

    1978-01-01

    According to the analysis of the magnetic records from the Triad satellite, it has been found that there are two regions of the field-aligned current of magnetospheric origin along the auroral oval; Region 1 in higher latitude and Region 2 in lower latitude. These currents seem to have important effect on the distribution of electric field and current in the ionosphere, in addition to the Sq electric field and current of ionospheric origin. The global current systems generated by the field-aligned current were calculated, using some simplified ionospheric models. The effect of the field-aligned current on the distribution of electric field and current of the ionosphere at middle and low latitudes was investigated. (Yoshimori, M.)

  17. Spin-dependent scattering and the spin polarization of a diffusive current in partly disordered L10 epitaxial FePd

    International Nuclear Information System (INIS)

    Seemann, K M; Hickey, M C; Baltz, V; Hickey, B J; Marrows, C H

    2010-01-01

    We report magnetic domain wall (DW) resistance in epitaxial films of FePd. When equal numbers of Fe and Pd atoms are present, this material forms an ordered structure with alternating crystal planes of Fe and Pd. We prepared films enriched with Pd to varying degrees, gradually degrading this structure. As might be expected, this increased the electrical resistivity of the films by introducing extra defects that can scatter electrons. However, unexpectedly, the additional resistance arising from the ∼10 nm thick DWs rose as a proportion of the overall resistivity, roughly doubling when halving the degree of chemical ordering-as determined from x-ray diffraction measurements-within the films. These data can be used to infer a rise in the spin polarization of the current flowing in the layers when extra Pd atoms are introduced. On the other hand, a separate measurement of spin polarization using a superconducting point contact technique that is insensitive to electron scattering revealed no changes as extra Pd was introduced. We conclude that Pd atoms scatter electrons of one spin far more strongly than the other, suggesting a possible means of producing highly spin-polarized currents for use in spintronic devices.

  18. Sickness behavior induced by endotoxin can be mitigated by the dietary soluble fiber, pectin, through up-regulation of IL-4 and Th2 polarization

    OpenAIRE

    Sherry, Christina L.; Kim, Stephanie S.; Dilger, Ryan N.; Bauer, Laura L.; Moon, Morgan L.; Tapping, Richard I.; Fahey, George C.; Tappenden, Kelly A.; Freund, Gregory G.

    2010-01-01

    Peripheral activation of the immune system by infectious agents triggers the brain-cytokine system causing sickness behaviors which profoundly impact well-being. Dietary fiber is a beneficial foodstuff that, from a gastrointestinal tract perspective, exists in both insoluble and soluble forms. We show that a diet rich in soluble fiber protects mice from endotoxin-induced sickness behavior by polarizing mice Th2 when compared to a diet containing only insoluble fiber. Mice fed soluble fiber be...

  19. Progressive current degradation and breakdown behavior in GaN LEDs under high reverse bias stress

    International Nuclear Information System (INIS)

    Zhao Linna; Yu Peihong; Yan Dawei; Zhou Hao; Wu Jinbo; Cui Zhiqiang; Gu Xiaofeng; Guo Zixiang; Sun Huarui

    2017-01-01

    The progressive current degradation and breakdown behaviors of GaN-based light emitting diodes under high reverse-bias stress are studied by combining the electrical, optical, and surface morphology characterizations. The current features a typical “soft breakdown” behavior, which is linearly correlated to an increase of the accumulative number of electroluminescence spots. The time-to-failure for each failure site approximately obeys a Weibull distribution with slopes of about 0.67 and 4.09 at the infant and wear-out periods, respectively. After breakdown, visible craters can be observed at the device surface as a result of transient electrostatic discharge. By performing focused ion beam cuts coupled with scan electron microscope, we observed a local current shunt path in the surface layer, caused by the rapid microstructure deterioration due to significant current heating effect, consistent well with the optical beam induced resistance change observations. (paper)

  20. ON THE ANODIC POLARIZATION BEHAVIOR OF CARBON STEEL IN HANFORD NUCLEAR WASTES

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER, K.D.

    2007-01-31

    The effect of the important chemical constituents in the Hanford nuclear waste simulant on the anodic behavior of carbon steel was studied. Specifically, the effect of pH, nitrite concentration, nitrite/nitrate concentration ratios, total organic carbon and the chloride concentration on the open circuit potential, pitting potential and repassivation potential was evaluated. It was found that pH adjusting, although capable of returning the tank chemistry back to specification, did not significantly reduce the corrosivity of the stimulant compared to the present condition. Nitrite was found to be a potent inhibitor for carbon steel. A critical concentration of approximately 1.2M appeared to be beneficial to increase the difference of repassivation potential and open circuit potential considerably and thus prevent pitting corrosion from occurring. No further benefit was gained when increasing nitrite concentration to a higher level. The organic compounds were found to be weak inhibitors in the absence of nitrite and the change of chloride from 0.05M to 0.2M did not alter the anodic behavior dramatically.

  1. ON THE ANODIC POLARIZATION BEHAVIOR OF CARBON STEEL IN HANFORD NUCLEAR WASTES

    International Nuclear Information System (INIS)

    BOOMER, K.D.

    2007-01-01

    The effect of the important chemical constituents in the Hanford nuclear waste simulant on the anodic behavior of carbon steel was studied. Specifically, the effect of pH, nitrite concentration, nitrite/nitrate concentration ratios, total organic carbon and the chloride concentration on the open circuit potential, pitting potential and repassivation potential was evaluated. It was found that pH adjusting, although capable of returning the tank chemistry back to specification, did not significantly reduce the corrosivity of the stimulant compared to the present condition. Nitrite was found to be a potent inhibitor for carbon steel. A critical concentration of approximately 1.2M appeared to be beneficial to increase the difference of repassivation potential and open circuit potential considerably and thus prevent pitting corrosion from occurring. No further benefit was gained when increasing nitrite concentration to a higher level. The organic compounds were found to be weak inhibitors in the absence of nitrite and the change of chloride from 0.05M to 0.2M did not alter the anodic behavior dramatically

  2. Electrical characterization of polymer matrix — TiO2 filler composites through isothermal polarization / depolarization currents and I-V tests

    Science.gov (United States)

    Stavrakas, Ilias; Triantis, Dimos; Hloupis, George; Moutzouris, Konstantinos

    2014-04-01

    Specimens of polymer matrix — ceramic TiO2 filler composites were prepared. The contribution of the filler content on the electrical conductivity and energy storage properties of the samples was examined. I-V and Isothermal Polarization/Depolarization Current (IPC/IDC) measurements were conducted. Dc conductivity values directly calculated from the I-V curves exhibited excellent agreement with corresponding values derived from the IPC/IDC recordings. Standard models were employed for fitting the IPC/IDC data. In specific, the short and the very long depolarization times were fitted by use of power laws of different slopes, while the intermediate depolarization times were fitted as a sum of three exponential decays. The present study reveals a strong dependence of the depolarization and polarization processes, as well as of the dc conductivity, on the filler concentration.

  3. Measurement of neutral current deep inelastic e{sup +}p scattering cross sections with longitudinally polarized positrons with ZEUS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Wlasenko, Michal

    2009-05-15

    Measurements of neutral current deep inelastic scattering of protons colliding with longitudinally polarized positrons, performed with data recorded in years 2006 and 2007 with the ZEUS detector, corresponding to an integrated luminosity of L=113.3 pb{sup -1}, are presented. The single-differential cross sections d{sigma}/dQ{sup 2}, d{sigma}/dx, d{sigma}/dy and the double-differential reduced cross section {sigma} were measured in the kinematic region of 185polarization asymmetry A{sup +} and the generalized structure function x F{sub 3} were extracted. All measurements agree well with the predictions of the Standard Model. (orig.)

  4. Electrokinetics and behavior near the interface of colloidal particles in non-polar dispersions.

    Science.gov (United States)

    Prasad, Manoj; Strubbe, Filip; Beunis, Filip; Neyts, Kristiaan

    2017-08-23

    The electrokinetics and charging of nonpolar colloidal dispersions subjected to a voltage are investigated by electric current and optical measurements. From electric current measurements in response to an alternating triangular voltage with a peak value of a few hundred volts, we find that polystyrene toner particles are compacted near the electrodes and their charge increases by more than a factor of 20. The important increase of charge is interpreted by a mechanism in which counter charges, which are originally at the particle surface, are desorbed. Optical measurements performed under a dc voltage of the order of a few hundred volts demonstrate that the charge of the particles can again decrease or even be inverted. These phenomena are attributed to the movement of counter charged species from the interface layers onto the surface of the particles. The findings of this study are relevant for electrophoretic displays and liquid toner printing.

  5. Emotional or Behavioral Disorders: Background and Current Status of the E/BD Terminology and Definition.

    Science.gov (United States)

    Forness, Steven R.; Kavale, Kenneth A.

    2000-01-01

    This article reviews the development and current status of alternatives to the federal definition of emotional disturbance or behavior disorders. It notes that several states are now revising their own terminologies or definitions in response to the 1997 reauthorization of the Individuals with Disabilities Education Act that dropped the term…

  6. Emotional and Behavioral Disorders in South Korea: Current Status and Issues

    Science.gov (United States)

    Kim, Joungmin; Kim, Kyeong-hwa

    2016-01-01

    In South Korea, there is no consensus on the definition of emotional and behavioral disorders (EBD). This column focuses on how the definition has affected the prevalence rates and services available for students with EBDs. Of the legal, clinical, and educational definitions, the legal definition of EBDs is currently in common use, which raises…

  7. Experimental and analytical analysis of polarization and water transport behaviors of hydrogen alkaline membrane fuel cell

    Science.gov (United States)

    Huo, Sen; Zhou, Jiaxun; Wang, Tianyou; Chen, Rui; Jiao, Kui

    2018-04-01

    Experimental test and analytical modeling are conducted to investigate the operating behavior of an alkaline electrolyte membrane (AEM) fuel cell fed by H2/air (or O2) and explore the effect of various operating pressures on the water transfer mechanism. According to the experimental test, the cell performance is greatly improved through increasing the operating pressure gradient from anode to cathode which leads to significant liquid water permeation through the membrane. The high frequency resistance of the A901 alkaline membrane is observed to be relatively stable as the operating pressure varies based on the electrochemical impedance spectroscopy (EIS) method. Correspondingly, based on the modeling prediction, the averaged water content in the membrane electrode assembly (MEA) does not change too much which leads to the weak variation of membrane ohmic resistance. This reveals that the performance enhancement should give the credit to better electro-chemical reaction kinetics for both the anode and cathode, also prone by the EIS results. The reversion of water back diffusion direction across the membrane is also observed through analytical solution.

  8. Study of the Polarization Behavior of Ce0.9Gd0.1O2-δ Single Crystals below 350°C to Room Temperature

    DEFF Research Database (Denmark)

    Neuhaus, K.; Bernemann, M.; Hansen, Karin Vels

    2016-01-01

    was investigated by mapping the introduced defect gradient and its decay with time using Kelvin probe force microscopy. The generated surface potential gradients were found to have a diameter of up to 1 μm, which is explained by the local ionization of defect associates by the applied high electric field....... Measurements were performed at room temperature and 50°C. The polarization behavior of the Ce0.9Gd0.1O2-δ single crystals was compared to cyclovoltammetry and polarization-relaxation experiments at T ≤ 350°C and in dry air or nitrogen which were performed using a specially suited AFM (Controlled Atmosphere...

  9. Comparison of Electron Transmittance and Tunneling Current through a Trapezoidal Potential Barrier with Spin Polarization Consideration by using Analytical and Numerical Approaches

    Science.gov (United States)

    Nabila, Ezra; Noor, Fatimah A.; Khairurrijal

    2017-07-01

    In this study, we report an analytical calculation of electron transmittance and polarized tunneling current in a single barrier heterostructure of a metal-GaSb-metal by considering the Dresselhaus spin orbit effect. Exponential function, WKB method and Airy function were used in calculating the electron transmittance and tunneling current. A Transfer Matrix Method, as a numerical method, was utilized as the benchmark to evaluate the analytical calculation. It was found that the transmittances calculated under exponential function and Airy function is the same as that calculated under TMM method at low electron energy. However, at high electron energy only the transmittance calculated under Airy function approach is the same as that calculated under TMM method. It was also shown that the transmittances both of spin-up and spin-down conditions increase as the electron energy increases for low energies. Furthermore, the tunneling current decreases with increasing the barrier width.

  10. No evidence for orbital loop currents in charge-ordered YBa2Cu3O6 +x from polarized neutron diffraction

    Science.gov (United States)

    Croft, T. P.; Blackburn, E.; Kulda, J.; Liang, Ruixing; Bonn, D. A.; Hardy, W. N.; Hayden, S. M.

    2017-12-01

    It has been proposed that the pseudogap state of underdoped cuprate superconductors may be due to a transition to a phase which has circulating currents within each unit cell. Here, we use polarized neutron diffraction to search for the corresponding orbital moments in two samples of underdoped YBa2Cu3O6 +x with doping levels p =0.104 and 0.123. In contrast to some other reports using polarized neutrons, but in agreement with nuclear magnetic resonance and muon spin rotation measurements, we find no evidence for the appearance of magnetic order below 300 K. Thus, our experiment suggests that such order is not an intrinsic property of high-quality cuprate superconductor single crystals. Our results provide an upper bound for a possible orbital loop moment which depends on the pattern of currents within the unit cell. For example, for the CC-θI I pattern proposed by Varma, we find that the ordered moment per current loop is less than 0.013 μB for p =0.104 .

  11. Excitation of Self-Localized Spin-Wave Bullets by Spin-Polarized Current in In-Plane Magnetized Magnetic Nano-Contacts: A Micromagnetic Study

    Science.gov (United States)

    2007-10-08

    excitation of microwave spin waves.3,10,11 The analytical theory of spin-wave excitation in magnetic nanocontacts by spin-polarized current performed...linear theory ,3 the propagating spin- wave mode excited at the threshold is a cylindrical spin- wave with the wave vector kL=1.2/Rc and frequency L... Oersted magnetic field, and/or by any other small interaction, neglected in the micromagnetic model. To make the excitation of subcritical modes12,15

  12. On a distribution of electric fields caused by the northern component of the interplanetary magnetic field in the absence of longitudinal currents in the winter polar cap

    International Nuclear Information System (INIS)

    Uvarov, V.M.

    1984-01-01

    Data on the distribution of electric fields, conditioned by the northern component of the interplanetary magnetic field Bsub(z), have been discussed. The problem of electric field excitation is reduced to the solution of equations of continuity for the current in three regions: northern and southern polar caps and region beyond the caps. At the values Bsub(z)>0 in the ranqe of latitudes phi >= 80 deg the localization of convection conversion effect is obtained in calculations for summer cap and it agrees with the data of direct measurements

  13. Transcranial direct current stimulation of the frontal-parietal-temporal area attenuates smoking behavior.

    Science.gov (United States)

    Meng, Zhiqiang; Liu, Chang; Yu, Chengyang; Ma, Yuanye

    2014-07-01

    Many brain regions are involved in smoking addiction (e.g. insula, ventral tegmental area, prefrontal cortex and hippocampus), and the manipulation of the activity of these brain regions can show a modification of smoking behavior. Low current transcranial direct current stimulation (tDCS) is a noninvasive way to manipulate cortical excitability, and thus brain function and associated behaviors. In this study, we examined the effects of inhibiting the frontal-parietal-temporal association area (FPT) on attention bias to smoking-related cues and smoking behavior in tobacco users. This inhibition is induced by cathodal tDCS stimulation. We tested three stimulation conditions: 1) bilateral cathodal over both sides of FPT; 2) cathodal over right FPT; and 3) sham-tDCS. Visual attention bias to smoking-related cues was evaluated using an eye tracking system. The measurement for smoking behavior was the number of daily cigarettes consumed before and after tDCS treatment. We found that, after bilateral cathodal stimulation of the FPT area, while the attention to smoking-related cues showed a decreased trend, the effects were not significantly different from sham stimulation. The daily cigarette consumption was reduced to a significant level. These effects were not seen under single cathodal tDCS or sham-tDCS. Our results show that low current tDCS of FPT area attenuates smoking cue-related attention and smoking behavior. This non-invasive brain stimulation technique, targeted at FPT areas, might be a promising method for treating smoking behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. The modulation of two motor behaviors by persistent sodium currents inXenopus laevistadpoles.

    Science.gov (United States)

    Svensson, Erik; Jeffreys, Hugo; Li, Wen-Chang

    2017-07-01

    Persistent sodium currents ( I NaP ) are common in neuronal circuitries and have been implicated in several diseases, such as amyotrophic lateral sclerosis (ALS) and epilepsy. However, the role of I NaP in the regulation of specific behaviors is still poorly understood. In this study we have characterized I NaP and investigated its role in the swimming and struggling behavior of Xenopus tadpoles. I NaP was identified in three groups of neurons, namely, sensory Rohon-Beard neurons (RB neurons), descending interneurons (dINs), and non-dINs (neurons rhythmically active in swimming). All groups of neurons expressed I NaP , but the currents differed in decay time constants, amplitudes, and the membrane potential at which I NaP peaked. Low concentrations (1 µM) of the I NaP blocker riluzole blocked I NaP ~30% and decreased the excitability of the three neuron groups without affecting spike amplitudes or cellular input resistances. Riluzole reduced the number of rebound spikes in dINs and depressed repetitive firing in RB neurons and non-dINs. At the behavior level, riluzole at 1 µM shortened fictive swimming episodes. It also reduced the number of action potentials neurons fired on each struggling cycle. The results show that I NaP may play important modulatory roles in motor behaviors. NEW & NOTEWORTHY We have characterized persistent sodium currents in three groups of spinal neurons and their role in shaping spiking activity in the Xenopus tadpole. We then attempted to evaluate the role of persistent sodium currents in regulating tadpole swimming and struggling motor outputs by using low concentrations of the persistent sodium current antagonist riluzole. Copyright © 2017 the American Physiological Society.

  15. Anomalous Hall effect and current spin polarization in Co2Fe X Heusler compounds (X =Al , Ga , In , Si , Ge , and Sn ): A systematic ab initio study

    Science.gov (United States)

    Huang, Hung-Lung; Tung, Jen-Chuan; Guo, Guang-Yu

    2015-04-01

    Co-based Heusler compounds are ferromagnetic with a high Curie temperature and a large magnetization density, and thus are promising for spintronic applications. In this paper, we perform a systematic ab initio study of two principal spin-related phenomena, namely, anomalous Hall effect and current spin polarization, in Co2-based Heusler compounds Co2Fe X (X =Al , Ga , In , Si , Ge , Sn ) in the cubic L2 1 structure within the density functional theory with the generalized gradient approximation (GGA). The accurate all-electron full-potential linearized augmented plane-wave method is used. First, we find that the spin polarization of the longitudinal current (PL) in Co2Fe X (X =Al , Ga , In , Al0.5Si0.5 , and Sn ) is ˜100 % even though that of the electronic states at the Fermi level (PD) is not. Further, the other compounds also have a high current spin polarization with PL>85 %. This indicates that all the Co2Fe X compounds considered are promising for spin-transport devices. Interestingly, PD is negative in Co2Fe X (X =Si , Ge , and Sn ), differing in sign from the PL as well as that from the transport experiments. Second, the calculated anomalous Hall conductivities (AHCs) are moderate, being within 200 S/cm, and agree well with the available experiments on a highly L2 1 ordered Co2FeSi specimen although they differ significantly from the reported experiments on other compounds where the B2 antisite disorders were present. Surprisingly, the AHC in Co2FeSi decreases and then changes sign when Si is replaced by Ge and finally by Sn. Third, the calculated total magnetic moments agree well with the corresponding experimental ones in all the studied compounds except Co2FeSi where a difference of 0.3 μB/f .u . exists. We also perform the GGA plus on-site Coulomb interaction U calculations in the GGA + U scheme. We find that including the U affects the calculated total magnetic moment, spin polarization and AHC significantly, and in most cases, unfortunately

  16. Formal behavioral evaluation of enrichment programs on a zookeeper's schedule: a case study with a polar bear (Ursus Maritimus) at the Bronx Zoo.

    Science.gov (United States)

    Canino, Wendy; Powell, David

    2010-01-01

    We conducted a brief study of the effectiveness of environmental enrichment for a polar bear at the Bronx Zoo with two objectives in mind. First we wanted to determine if a novel method of collecting data that easily fits into a zookeeper's work routine would produce usable data and if so, we wanted to evaluate the effectiveness of some new items that had been purchased for enriching the polar bear in reducing his pacing behavior. Observations were recorded for 119 days over a period of 5 months from April 2007 through August 2007. Five new items and eight previously used items were rotated and presented to the polar bear in the morning and afternoon. We recorded the bear's behavior five times per day as we passed by his exhibit during our regular work routine. Predictably, we found that the newer enrichment items were more effective at increasing play and decreasing pacing, as well as other more subtle effects on his behavior that helped us to design a better enrichment routine. More importantly, we found that this method of "multi-point scan sampling" was effective at producing ample and reliable data that could be used to analyze the bear's behavior without adding significant work to the keepers' daily routine. (c) 2009 Wiley-Liss, Inc.

  17. An evaluation of the environmental fate and behavior of munitions materiel (Tetryl and polar metabolites of TNT) in soil and plant systems. Environmental fate and behavior of tetryl

    Energy Technology Data Exchange (ETDEWEB)

    Fellows, R.J.; Harvey, S.D.; Cataldo, D.A.

    1993-09-01

    The objective of the present studies was to elucidate the environmental behavior and fate of 2,4,6trintrophenylmethylnitramine (tetryl) in the soil/plant system in three different types of soils incubated for 60 days. No tetryl was detectable after 11 days; most of the radiolabel was associated with non-extractable soil components and four transformation products appeared rapidly, of which two were identified as N-methyl-2,4,6-trintroaniline and N-methyl-aminodinitroaniline isomer. Short-term hydroponic studies indicated no significant difference in uptake rates for the three plant species employed. Kinetic studies indicated that plants have a high affinity and capacity for absorbing tetryl. Partitioning patterns indicated that the root is the major accumulation site for tetryl. Chemical fractionation and analyses of tissues showed rapid metabolism of tetryl in tissues of all species, which proceeded toward more polar metabolic products. Plant maturity studies indicated significant differences in the total relative uptake of tetryl by all three plant species based on soil type.

  18. Effects of pulse current stimulation on the thermal fatigue crack propagation behavior of CHWD steel

    International Nuclear Information System (INIS)

    Lin, H.Q.; Zhao, Y.G.; Gao, Z.M.; Han, L.G.

    2008-01-01

    The fatigue crack propagating behaviors of cast hot working die (CHWD) steel untreated and treated by an electric current in the intermediate stage of thermal fatigue were investigated in the present study. The circle/elliptical heating affected zone (HAZ) was formed ahead of the notch tip on the fatigued specimens after pulse electric current stimulation. Both SEM observation and X-ray diffraction analysis revealed that pulse electric current stimulation refined grains/subgrains in the HAZs. With the prolonging of discharging duration, the grains/subgrains decreased in size and the dislocation density and microhardness increased gradually. The grain refinement and dislocation density increase played an important role in the material strengthening, which inevitably enhanced the propagation resistance and delayed the propagation of thermal fatigue cracks. Therefore, the pulse electric current stimulation was an effective method to improve the service lifetime of die material

  19. Retrospective reports of child feeding practices, current eating behaviors, and BMI in college students.

    Science.gov (United States)

    Galloway, Amy T; Farrow, Claire V; Martz, Denise M

    2010-07-01

    Research concerning child feeding practices has focused on children and adolescents, and little is known about how feeding practices used in childhood relate to eating behaviors and weight status in early adulthood. We assessed college students' and their parents' retrospective reports of child feeding practices used when the students were in middle childhood. We also assessed the college students' current reports of their eating behaviors using the Dutch Eating Behavior Questionnaire (DEBQ) and the Intuitive Eating Scale (IES), and measured their current BMI. Results showed that college students' and their parents' reports about previous parental use of child feeding practices were not correlated. Parent reports of their own use of child feeding practices were more related to students' eating behaviors and BMI than were students' recollections about feeding practices used by their parents. An analysis of gender effects showed that there were positive correlations between parental child feeding practices, BMI, and emotional eating for female students. These relationships did not exist for male students. The results suggest that child feeding practices recollected by parents are linked to the development of emotional eating and weight status of women in early adulthood.

  20. Use of cyclic current reversal polarization voltammetry for investigating the relationship between corrosion resistance and heat-treatment induced variations in microstructures of 400 C martensitic stainless steels

    Science.gov (United States)

    Ambrose, John R.

    1992-01-01

    Software for running a cyclic current reversal polarization voltammagram has been developed for use with a EG&G Princeton Applied Research Model 273 potentiostat/galvanostat system. The program, which controls the magnitude, direction and duration of an impressed galvanostatic current, will produce data in ASCII spreadsheets (Lotus, Quattro) for graphical representation of CCRPV voltammograms. The program was used to determine differences in corrosion resistance of 440 C martenstic stainless steel produced as a result of changes in microstructure effected by tempering. It was determined that tempering at all temperatures above 400 F resulted in increased polarizability of the material, with the increased likelihood that pitting would be initiated upon exposure to marine environments. These results will be used in development of remedial procedures for lowering the susceptibility of these alloys toward the stress corrosion cracking experienced in bearings used in high pressure oxygen turbopumps used in the main engines of space shuttle orbiters.

  1. Polarization Optics

    OpenAIRE

    Fressengeas, Nicolas

    2010-01-01

    The physics of polarization optics *Polarized light propagation *Partially polarized light; DEA; After a brief introduction to polarization optics, this lecture reviews the basic formalisms for dealing with it: Jones Calculus for totally polarized light and Stokes parameters associated to Mueller Calculus for partially polarized light.

  2. Transcranial direct current stimulation (tDCS) reveals a dissociation between SNARC and MARC effects: Implication for the polarity correspondence account.

    Science.gov (United States)

    Di Rosa, Elisa; Bardi, Lara; Umiltà, Carlo; Masina, Fabio; Forgione, Margherita; Mapelli, Daniela

    2017-08-01

    The concept of stimulus response compatibility (SRC) refers to the existence of a privileged association between a specific stimulus feature and a specific response feature. Two examples of SRC are the Spatial Numerical Association of Response Codes (SNARC) and the Markedness Association of Response Codes (MARC) effects. According to the polarity correspondence principle, these two SRC effects occur because of a match between the most salient dimensions of stimulus and response. Specifically, the SNARC effect would be caused by a match between right-sided responses and large numbers, while a match between right-sided responses and even numbers would give rise to the MARC effect. The aim of the present study was to test the validity of the polarity correspondence principle in explaining these two SRC effects. To this end, we applied transcranial direct current stimulation (tDCS) over left and right posterior parietal cortex (PPC), which is thought to be the neural basis of salience processing, during a parity judgement task. Results showed that cathodal tDCS over the PPC significantly reduced the MARC effect but did not affect the SNARC effect, suggesting a dissociation between the two effects. That is, the MARC would rely on a salience processing mechanism, whereas the SNARC would not. Despite this interpretation is in need of further experimental confirmations (i.e., testing different tasks or using different tDCS montages), our results suggest that the polarity correspondence principle can be a plausible explanation only for the MARC effect but not for the SNARC effect. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. A model of the plasma flow and current in Saturn's polar ionosphere under conditions of strong Dungey cycle driving

    Directory of Open Access Journals (Sweden)

    C. M. Jackman

    2006-05-01

    Full Text Available We propose a simple model of the flow and currents in Saturn's polar ionosphere. This model is motivated by theoretical reasoning, and guided quantitatively by in situ field and flow data from space missions, ground-based IR Doppler measurements, and Hubble Space Telescope images. The flow pattern consists of components which represent (1 plasma sub-corotation in the middle magnetosphere region resulting from plasma pick-up and radial transport from internal sources; (2 the Vasyliunas-cycle of internal plasma mass-loss down the magnetospheric tail at higher latitudes; and (3 the polar Dungey-cycle flow driven by the solar wind interaction. Upstream measurements of the interplanetary magnetic field (IMF indicate the occurrence of both extended low-field rarefaction intervals with essentially negligible Dungey-cycle flow, and few-day high-field compression regions in which the Dungey-cycle voltage peaks at a few hundred kV. Here we model the latter conditions when the Dungey-cycle is active, advancing on previous axi-symmetric models which may be more directly applicable to quiet conditions. For theoretical convenience the overall flow pattern is constructed by adding together two components - a purely rotational flow similar to previous axi-symmetric models, and a sun-aligned twin vortex representing the dawn-dusk asymmetry effects associated with the Vasyliunas-and Dungey-cycle flows. We calculate the horizontal ionospheric current associated with the flow and the field-aligned current from its divergence. These calculations show that a sheet of upward-directed field-aligned current flows at the boundary of open field lines which is strongly modulated in local-time by the Dungey-cycle flows. We then consider implications of the field-aligned current for magnetospheric electron acceleration and aurorae using two plasma source populations (hot outer magnetospheric electrons and cool dense magnetosheath electrons. Both sources display a

  4. Real-space distribution of the Hall current densities and their spin polarization in nonmagnetic zine-blende semiconductors

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel; Drchal, Václav

    2012-01-01

    Roč. 86, č. 19 (2012), "195204-1"-"195204-8" ISSN 1098-0121 R&D Projects: GA ČR(CZ) GAP204/11/1228 Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z10100520 Keywords : nonmagnetic semiconductors * spin Hall currents Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.767, year: 2012

  5. Visualization of the interfacial turbulence associated with remarkable faradaic current amplification at a polarized water/1,2-dichloroethane interface

    Czech Academy of Sciences Publication Activity Database

    Trojánek, Antonín; Mareček, Vladimír; Samec, Zdeněk

    2017-01-01

    Roč. 80, JUL 2017 (2017), s. 1-4 ISSN 1388-2481 R&D Projects: GA ČR GA17-09980S Institutional support: RVO:61388955 Keywords : Water/1,2-dichloroethane interface * Ion transfer * Current amplification Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 4.396, year: 2016

  6. Visualization of the interfacial turbulence associated with remarkable faradaic current amplification at a polarized water/1,2-dichloroethane interface

    Czech Academy of Sciences Publication Activity Database

    Trojánek, Antonín; Mareček, Vladimír; Samec, Zdeněk

    Roč. 80, JUL 2017 (2017), s. 1-4 ISSN 1388-2481 R&D Projects: GA ČR GA17-09980S Institutional support: RVO:61388955 Keywords : Water/1,2-dichloroethane interface * Ion transfer * Current amplification Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 4.396, year: 2016

  7. The interplanetary magnetic field By-dependent field-aligned current in the dayside polar cap under quiet conditions

    International Nuclear Information System (INIS)

    Yamauchi, M.; Araki, T.

    1989-01-01

    Spatial distribution and temporal variation of the interplanetary magnetic field (IMF) B y -dependent cusp region field-aligned currents (FACs) during quiet periods were studied by use of magnetic data observed by Magsat. The analysis was made for 11 events (each event lasts more than one and a half days) when the IMF B y component was steadily large and B x was relatively small (|B z | y |). Results of the analysis of total 62 half-day periods for the IMF B y -dependent cusp region FAC are summarized as follows: (1) the IMF B y -dependent cusp region FAC is located at around 86 degree-87 degree invariant latitude local noon, which is more poleward than the location of the IMF B z -dependent cusp region FAC; (2) the current density of this FAC is greater than previous studies (≥ 4 μA/m 2 for IMF B y = 6 nT); (3) there are two time scales for the IMF B y -dependent cusp region FAC to appear: the initial rise of the current is on a short time scale, ∼ 10 min, and it is followed by a gradual increase on a time scale of several hours to a half day; (4) the seasonal change of this FAC is greater than that of the nightside region 1 or region 2 FACs; (5) the IMF B z -dependent cusp region FAC is not well observed around the cusp when the IMF B y -dependent cusp region FAC is intense

  8. Risk of behavioral and adaptive functioning difficulties in youth with previous and current sleep disordered breathing.

    Science.gov (United States)

    Perfect, Michelle M; Archbold, Kristen; Goodwin, James L; Levine-Donnerstein, Deborah; Quan, Stuart F

    2013-04-01

    To examine the rates of behavioral and adaptive functioning difficulties among youth who never had sleep disordered breathing (SDB), had remitted SDB, had incident SDB, or had persistent SDB; and to determine if there were increased odds of behavioral difficulties among youth with varying SDB histories relative to those who never had SDB. 263 youth had valid polysomnography and neurobehavioral data at two time points approximately 5 years apart from the prospective Tucson Children's Assessment of Sleep Apnea study. Primary outcomes were the behavior assessment scale for children-2(nd) Edition parent report form (BASC-PRF) and Self-Report of Personality (SRP), and the Adaptive Behavior Assessment System-2(nd) Edition (ABAS-2). Compared to those who never had SDB, individuals with persistent SDB had significant odds and met more cutoff scores on the BASC-2-PRF externalizing problems composite (odds ratio [OR] 3.29; 8.92% vs. 35.3%), behavioral symptoms index (OR 6.82; 7.4% vs. 35.3%) and Hyperactivity subscale (OR 6.82; 11.1% vs. 41.2%). Similarly, greater difficulties was seen for the group with persistent SDB (relative to never) on the ABAS-2 social domain (OR 3.39; 22% vs. 50%), and Communication (OR 4.26; 15% vs. 42.9%) and Self-Care subscales (OR = 2.97; 25.2% vs. 50%). Relative to youth who never had SDB, youth who developed SDB at Time 2 had compromised adaptive skills as evidenced by the BASC-2 PRF adaptive behavior composite (OR 3.34; 15.6% vs. 38.1%) and the ABAS-2 general adaptive composite (OR 2.83; 20.5% vs. 42.1%). Youth with current SDB exhibited hyperactivity, attention problems, aggressivity, lower social competency, poorer communication, and/or diminished adaptive skills.

  9. A Small Potassium Current in AgRP/NPY Neurons Regulates Feeding Behavior and Energy Metabolism

    Directory of Open Access Journals (Sweden)

    Yanlin He

    2016-11-01

    Full Text Available Neurons that co-express agouti-related peptide (AgRP and neuropeptide Y (NPY are indispensable for normal feeding behavior. Firing activities of AgRP/NPY neurons are dynamically regulated by energy status and coordinate appropriate feeding behavior to meet nutritional demands. However, intrinsic mechanisms that regulate AgRP/NPY neural activities during the fed-to-fasted transition are not fully understood. We found that AgRP/NPY neurons in satiated mice express high levels of the small-conductance calcium-activated potassium channel 3 (SK3 and are inhibited by SK3-mediated potassium currents; on the other hand, food deprivation suppresses SK3 expression in AgRP/NPY neurons, and the decreased SK3-mediated currents contribute to fasting-induced activation of these neurons. Genetic mutation of SK3 specifically in AgRP/NPY neurons leads to increased sensitivity to diet-induced obesity, associated with chronic hyperphagia and decreased energy expenditure. Our results identify SK3 as a key intrinsic mediator that coordinates nutritional status with AgRP/NPY neural activities and animals’ feeding behavior and energy metabolism.

  10. [Pathological buying. A review of the current knowledge regarding this condition of behavioral excess].

    Science.gov (United States)

    Müller, A; de Zwaan, M

    2010-04-01

    Compulsive buying is characterized by frequent excessive purchasing of items that are primarily not needed or used. The compulsive buying behavior results in mental, social, financial and often legal problems. Although compulsive buying affects a significant percentage of the general population and has received increasing attention in research, it has largely been ignored in clinical practice. Compulsive buying disorder is currently conceptualized as an"impulse control disorder not otherwise specified". However, the appropriate classification continues to be debated. Compulsive buying is associated with significant psychiatric co-morbidity, especially with depressive, anxiety, obsessive-compulsive, substance use, personality, and other impulse control disorders. Small controlled trials failed to confirm the efficacy of antidepressants in the treatment of compulsive buying disorder, whereas early evidence suggests that cognitive behavioral therapy is helpful in alleviating compulsive buying symptoms. Further research is needed to establish a better understanding of etiology, classification, and treatment strategies.

  11. Consistency of self-reported sexual behavior and condom use among current sex partners.

    Science.gov (United States)

    Sison, Jennette D; Gillespie, Brenda; Foxman, Betsy

    2004-05-01

    The objective of this study was to determine concordance in sex partner reports of frequency of vaginal and oral intercourse and condom use. Self-reported behaviors among 112 women treated for urinary tract infection (UTI), sore throats, or receiving birth control at a student health service were compared with that of their current sex partner. Correlation was excellent for frequencies of vaginal intercourse (r = 0.88), cunnilingus (r = 0.72), fellatio (r = 0.76), and condom use (r = 0.86), but women with UTI compared with women without UTI reported greater frequency of sexual activity than their sex partner. This effect overwhelmed the modest increases in correlation associated with duration of relationship and marital status. Women with genitourinary symptoms may over-recall frequency of sexual behavior compared to women without these symptoms. Knowing the extent of this recall bias will assist in the interpretation of data and appropriate correction of parameters when included in prediction models.

  12. Behavioral Responses Of Fish To A Current-Based Hydrokinetic Turbine Under Mutlipe Operational Conditions: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Grippo, Mark A. [Argonne National Lab. (ANL), Argonne, IL (United States); Shen, Haixue [Univ. of Maine, Orono, ME (United States); Zydlewski, Gayle [Univ. of Maine, Orono, ME (United States); Rao, Shivanesh [Univ. of Maine, Orono, ME (United States); Goodwin, Andy [United States Army Engineer R & D Center, Vicksburg, MI (United States)

    2017-02-01

    There is significant interest in the interaction of aquatic organisms with current-based marine and hydrokinetic (MHK) technologies. Determining the potential impacts of MHK devices on fish behavior is critical to addressing the environmental concerns that could act as barriers to the permitting and deployment of MHK devices. To address these concerns, we use field monitoring and fish behavior models to characterize the behavioral responses of fish to MHK turbines and infer potential stimuli that may have elicited the observed behavioral changes.

  13. Effects of scan rate on the corrosion behavior SS 304 stainless steel in the nanofluid measured by Tafel polarization methods

    Energy Technology Data Exchange (ETDEWEB)

    Prajitno, Djoko Hadi [PSTNT-BATAN Jl. Tamansari 71 Bandung 40132, Indonesia, djokohp@batan.go.id (Indonesia)

    2015-09-30

    The Effects of scan rate on the Tafel polarization curve that is obtained to determine corrosion rate are conducted. The tafel polarization curves are obtained at different scan rates for Stainless Steel 304 in nanofluids contain 0.01 gpl nano particle ZrO{sub 2}. The corrosion stainless steel in nanofluid contains adm+0.01 gpl ZrO{sub 2} nanoparticles at different scan rate was performed by Tafel polarization. The results show that according corrosion potential examination of the stainless steel in nanofluid media 0.01gpl ZrO{sub 2} nanoparticle was actively corroded. The value of cathodic Tafel slope stainless steel in nanofluid at different scan rate relatively unchanged after polarization testing. Mean while the value of anodic Tafel slope stainless steel in nanofluid increase at different scan rate. The results of Tafel polarization technique show that corrosion rate of stainless steel in nanofluid increase with increasing scan rate. X ray diffraction examination of stainless steel after Tafel polarization depict that γ Fe phase is major phase in the surface of alloy.

  14. Spin currents and filtering behavior in zigzag graphene nanoribbons with adsorbed molybdenum chains

    International Nuclear Information System (INIS)

    García-Fuente, A; Gallego, L J; Vega, A

    2015-01-01

    By means of density-functional-theoretic calculations, we investigated the structural, electronic and transport properties of hydrogen-passivated zigzag graphene nanoribbons (ZGNRs) on which a one-atom-thick Mo chain was adsorbed (with or without one or two missing atoms), or in which the passivating hydrogen atoms were replaced by Mo atoms. Mo-passivated ZGNRs proved to be nonmagnetic. ZGNRs with an adsorbed defect-free Mo chain were most stable with the Mo atoms forming dimers above edge bay sites, which suppressed the magnetic moments of the C atoms in that half of the ribbon; around the Fermi level of these systems, each spin component had a transmission channel via the Mo sp z band and one had an additional channel created by polarization of the ZGNR π * band, leading to a net spin current. The absence of an Mo dimer from an Mo chain adsorbed at the ZGNR edge made the system a perfect spin filter at low voltage bias by suppressing the Mo sp z band channels. Thus this last kind of hybrid system is a potential spin valve. (paper)

  15. Population structure, behavior, and current threats to the sarus crane (Grus antigone antigone in Nepal

    Directory of Open Access Journals (Sweden)

    Kamal Raj Gosai

    2016-09-01

    Full Text Available The sarus crane (Grus antigone antigone is listed as “vulnerable” in the International Union for Conservation of Nature (IUCN Red List of Threatened Species. Sarus cranes are distributed in the lowlands, but most live outside protected areas, especially in agricultural areas and wetlands of Nepal. The continuous expansion of agricultural land and the reduction of wetland habitats pose the greatest threats to the conservation of the species. We studied the sarus crane in the Rupandehi District of Nepal to understand their population structure, behavior, and current threats. We used the line (i.e., road transect method from August 2013 to February 2014. The study area contained 147 sarus cranes. Agricultural land and wetland areas contained the highest number of sarus cranes. Our analysis showed that the population of sarus crane in the area has declined since 2007. Most sarus cranes lived in pairs. A single flock contained 13 cranes at maximum. Sarus crane behavior was not significantly different before and after the breeding seasons. Human–sarus crane conflict began when cranes started utilizing agricultural areas. The main threats to the hatching success and survival of sarus cranes in the Rupendehi District are egg theft and the hunting of cranes for meat. The findings of this study establish baseline information on the overall conservation status, habitat availability, and ecological behavior of sarus cranes in the district. We propose regular surveys to monitor sarus crane population levels in the face of multiple anthropogenic threats to their survival.

  16. Polarized Electrons at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1997-12-31

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously.initial operational experience with the polarized source will be presented.

  17. Polarized electrons at Jefferson laboratory

    International Nuclear Information System (INIS)

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously. Initial operational experience with the polarized source will be presented

  18. Behavioral and electroencephalographic evaluation of the anticonvulsive activity of Moringa oleifera leaf non-polar extracts and one metabolite in PTZ-induced seizures.

    Science.gov (United States)

    González-Trujano, María Eva; Martínez-González, Claudia Lizbeth; Flores-Carrillo, Maricela; Luna-Nophal, Sara Ibeth; Contreras-Murillo, Gerardo; Magdaleno-Madrigal, Víctor Manuel

    2018-01-15

    Moringa oleifera Lamarck is a species that has long been used in high demand in folk medicine, including for the treatment of epilepsy. Nevertheless, scientific studies demonstrating its anticonvulsant properties and the nature of the bioactive constituents are lacking. The aim of this study was to evaluate the anticonvulsant activities of the Moringa oleifera leaves in non-polar vs. polar extracts using behavioral and electroencephalographic (EEG) analyses in rodents. First, PTZ (80 mg/kg, i.p.)-induced tonic-clonic seizures were assayed via a dose-response (100, 200 and 300 mg/kg, i.p.) evaluation in mice. Then, a dosage of the extracts (100 or 300 mg/kg) and one metabolite (30 mg/kg, i.p.) was selected to evaluate its effect on PTZ (35 mg/kg, i.p.)-induced EEG paroxystic activities in rats compared to the effects of ethosuximide (reference anticonvulsant drug, 100 mg/kg, i.p.). Latent onset of the first paroxystic spike, first seizure and frequency as well as seizure severity, were determined using Racine's scale. Moringa oleifera ethanol and hexane extracts produced a delay in the seizure latency in mice and rats; this effect was improved in the presence of the hexane extract containing the active metabolite hexadecanoic acid. The anticonvulsant effects were corroborated in the spectral analysis by the potency of the EEG due to a reduction in the spike frequency and amplitude, as well as in the duration and severity of the seizures. The effects of the hexane extract resembled those observed in the reference antiepileptic drug ethosuximide. Moringa oleifera leaves possess anticonvulsant activities due to the complementary of the non-polar and polar constituents. However, the non-polar constituents appear to exert an important influence via the partial participation of fatty acids, providing evidence of the effects of this plant in epilepsy therapy. Copyright © 2017. Published by Elsevier GmbH.

  19. Particulate organic carbon export across the Antarctic Circumpolar Current at 10°E: Differences between north and south of the Antarctic Polar Front

    Science.gov (United States)

    Puigcorbé, Viena; Roca-Martí, Montserrat; Masqué, Pere; Benitez-Nelson, Claudia R.; Rutgers v. d. Loeff, Michiel; Laglera, Luis M.; Bracher, Astrid; Cheah, Wee; Strass, Volker H.; Hoppema, Mario; Santos-Echeandía, Juan; Hunt, Brian P. V.; Pakhomov, Evgeny A.; Klaas, Christine

    2017-04-01

    The vertical distribution of 234Th was measured along the 10°E meridian between 44°S and 53°S in the Antarctic Circumpolar Current (ACC) during the austral summer of 2012. The overarching goal of this work was to estimate particulate organic carbon (POC) export across three fronts: the Sub-Antarctic Front (SAF), the Antarctic Polar Front (APF) and the Southern Polar Front (SPF). Steady state export fluxes of 234Th in the upper 100 m ranged from 1600 to 2600 dpm m-2 d-1, decreasing with increasing latitude. Using large particle (>53 μm) C/234Th ratios, the 234Th-derived POC fluxes at 100 m ranged from 25 to 41 mmol C m-2 d-1. Observed C/234Th ratios decreased with increasing depth north of the APF while south of the APF, ratios remained similar or even increased with depth. These changes in C/234Th ratios are likely due to differences in the food web. Indeed, satellite images, together with macronutrients and dissolved iron concentrations suggest two different planktonic community structures north and south of the APF. Our results indicate that higher ratios of POC flux at 100 m to primary production occurred in nanophytoplankton dominated surface waters, where primary production rates were lower. Satellite images prior to the expedition suggest that the higher export efficiencies obtained in the northern half of the transect may be the result of the decoupling between production and export (Buesseler 1998). Transfer efficiencies to 400 m, i.e. the fraction of exported POC that reached 400 m, were found to be higher south of the APF, where diatoms were dominant and salps largely abundant. This suggests different remineralization pathways of sinking particles, influencing the transfer efficiency of exported POC to depth.

  20. Polarization in Sagittarius A*

    OpenAIRE

    Bower, Geoffrey C.

    2000-01-01

    We summarize the current state of polarization observations of Sagittarius A*, the compact radio source and supermassive black hole candidate in the Galactic Center. These observations are providing new tools for understanding accretion disks, jets and their environments. Linear polarization observations have shown that Sgr A* is unpolarized at frequencies as high as 86 GHz. However, recent single-dish observations indicate that Sgr A* may have strong linear polarization at frequencies higher...

  1. Barrier reduction via implementation of InGaN interlayer in wafer-bonded current aperture vertical electron transistors consisting of InGaAs channel and N-polar GaN drain

    International Nuclear Information System (INIS)

    Kim, Jeonghee; Laurent, Matthew A.; Li, Haoran; Lal, Shalini; Mishra, Umesh K.

    2015-01-01

    This letter reports the influence of the added InGaN interlayer on reducing the inherent interfacial barrier and hence improving the electrical characteristics of wafer-bonded current aperture vertical electron transistors consisting of an InGaAs channel and N-polar GaN drain. The current-voltage characteristics of the transistors show that the implementation of N-polar InGaN interlayer effectively reduces the barrier to electron transport across the wafer-bonded interface most likely due to its polarization induced downward band bending, which increases the electron tunneling probability. Fully functional wafer-bonded transistors with nearly 600 mA/mm of drain current at V GS  = 0 V and L go  = 2 μm have been achieved, and thus demonstrate the feasibility of using wafer-bonded heterostructures for applications that require active carrier transport through both materials

  2. Inhibited attachment disordered behavior in institutionalized preschool children: links with early and current relational experiences.

    Science.gov (United States)

    Corval, Raquel; Belsky, Jay; Baptista, Joana; Oliveira, Paula; Mesquita, Ana; Soares, Isabel

    2017-12-01

    Inhibited attachment disordered behavior (IADB) is characterized by difficulty in establishing an attachment relationship with a primary caregiver; is associated with persistent social and emotional problems; and is observed most frequently in contexts of pathological care such as institutional rearing. Here, we seek to enhance understanding of the conditions that give rise to IADB among institutionalized children by examining prior family experiences of neglect and deprivation and concurrent relational experiences at the institution. The sample is comprised of 146 children, between 36 and 78 months. IADB was assessed using a semi-structured interview administered to the child's primary caregiver. Results revealed that both pre-institutionalization experiences (e.g. parental abandonment) and current relational ones (e.g. low quality of child-caregiver relationship) predicted IADB. Findings are discussed in light of the need to promote conditions which foster the establishment and maintenance of the child's selective attachment to a caregiving figure.

  3. Behavioral couples treatment of alcohol and drug use disorders: current status and innovations.

    Science.gov (United States)

    Epstein, E E; McCrady, B S

    1998-09-01

    Research suggests that Behavioral Couples Therapy (BCT), tailored to treat alcohol problems, produces significant reduction in alcohol consumption and improvement in marital functioning. Having established basic clinical protocols for Alcohol Behavioral Couples Therapy (ABCT) and provided support for their efficacy, clinical researchers around the country continue to develop and study new applications of the basic ABCT treatment models, such as adding relapse prevention or Alcoholics Anonymous components. Recent research supporting the heterogeneity in the population of individuals with alcohol problems has prompted some researchers on ABCT to consider additional adaptations of the treatment models for specific subgroups of alcoholics, and for particular individual and couples characteristics. Adaptation of ABCT to treat new populations such as drug abusers, female alcoholics, and problem drinkers is under investigation. The current article provides an overview of theoretical and clinical aspects of ABCT, and research on efficacy of the basic model and on areas of innovation and adaptation to new populations. Directions for future research on ABCT are suggested.

  4. Polarized Proton Collisions at RHIC

    CERN Document Server

    Bai, Mei; Alekseev, Igor G; Alessi, James; Beebe-Wang, Joanne; Blaskiewicz, Michael; Bravar, Alessandro; Brennan, Joseph M; Bruno, Donald; Bunce, Gerry; Butler, John J; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Laster, Jonathan S; Lee, Roger C; Luccio, Alfredo U; Luo, Yun; MacKay, William W; Makdisi, Yousef; Marr, Gregory J; Marusic, Al; McIntyre, Gary; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oddo, Peter; Oerter, Brian; Osamu, Jinnouchi; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smith, Kevin T; Svirida, Dima; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Wilinski, Michelle; Zaltsman, Alex; Zelenski, Anatoli; Zeno, Keith; Zhang, S Y

    2005-01-01

    The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limite...

  5. Polarization at SLC

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1988-07-01

    The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs

  6. Current perspectives on Internet-delivered cognitive behavioral therapy for adults with anxiety and related disorders.

    Science.gov (United States)

    Mewton, Louise; Smith, Jessica; Rossouw, Pieter; Andrews, Gavin

    2014-01-01

    The aim of the current review is to provide a summary of research into Internet-delivered cognitive behavioral therapy (iCBT) for anxiety disorders. We include 37 randomized controlled trials that examined the efficacy of iCBT programs in adults (aged over 18 years), as compared with waiting list or active control. The included studies were identified from Medline searches and from reference lists, and only published data were included. Several trials of iCBT for generalized anxiety disorder, panic disorder, and social phobia were identified. Two trials of iCBT for obsessive-compulsive disorder were identified, whilst one trial each was identified for hypochondriasis, specific phobia (spiders), and post-traumatic stress disorder. Finally, there were five trials that focused on transdiagnostic therapy for either a range of comorbid anxiety disorders or comorbid anxiety and depression. Between-group effect sizes were moderate to large for all disorders, and ranged from 0.30 to 2.53. iCBT was found to be commensurate with face-to-face cognitive behavioral therapy whether delivered individually or in group format. Guidance may not be necessary for iCBT to be effective for immediate gains, but may be more important in longer-term maintenance of symptom improvement and maximizing patient adherence. The clinical experience of the individual providing guidance does not appear to impact treatment outcomes. Future research needs to focus on the optimal level of guidance required to generate maximum patient benefits, whilst balancing the efficient use of clinician time and resources. Evidence-based contraindications to iCBT should also be developed so that the choice of treatment modality accurately reflects patients' needs. Further research should be conducted into the effective elements of iCBT, as well as the extent to which therapy enhancers and advancing technology can be accommodated into established iCBT frameworks.

  7. Current perspectives on Internet delivered cognitive behavioral therapy for adults with anxiety and related disorders

    Directory of Open Access Journals (Sweden)

    Mewton L

    2014-01-01

    Full Text Available Louise Mewton, Jessica Smith, Pieter Rossouw, Gavin Andrews Clinical Research Unit for Anxiety and Depression, St Vincent’s Hospital, Sydney, NSW, Australia Abstract: The aim of the current review is to provide a summary of research into Internet-delivered cognitive behavioral therapy (iCBT for anxiety disorders. We include 37 randomized controlled trials that examined the efficacy of iCBT programs in adults (aged over 18 years, as compared with waiting list or active control. The included studies were identified from Medline searches and from reference lists, and only published data were included. Several trials of iCBT for generalized anxiety disorder, panic disorder, and social phobia were identified. Two trials of iCBT for obsessive-compulsive disorder were identified, whilst one trial each was identified for hypochondriasis, specific phobia (spiders, and post-traumatic stress disorder. Finally, there were five trials that focused on transdiagnostic therapy for either a range of comorbid anxiety disorders or comorbid anxiety and depression. Between-group effect sizes were moderate to large for all disorders, and ranged from 0.30 to 2.53. iCBT was found to be commensurate with face-to-face cognitive behavioral therapy whether delivered individually or in group format. Guidance may not be necessary for iCBT to be effective for immediate gains, but may be more important in longer-term maintenance of symptom improvement and maximizing patient adherence. The clinical experience of the individual providing guidance does not appear to impact treatment outcomes. Future research needs to focus on the optimal level of guidance required to generate maximum patient benefits, whilst balancing the efficient use of clinician time and resources. Evidence-based contraindications to iCBT should also be developed so that the choice of treatment modality accurately reflects patients’ needs. Further research should be conducted into the effective elements of

  8. Effects of direct current and pulse-reverse copper plating waveforms on the incubation behavior of self-annealing

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Min-Yuan [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 300 Taiwan (China); Chen, Kei-Wei, E-mail: kwchena@aa.nctu.edu.t [Department of Materials Science, National University of Tainan, Tainan, 700 Taiwan (China); Liu, Tzeng-Feng [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 300 Taiwan (China); Wang, Ying-Lang [Department of Materials Science, National University of Tainan, Tainan, 700 Taiwan (China); Feng, Hsien-Ping [Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 300 Taiwan (China)

    2010-10-01

    This study investigates spontaneous microstructural evolution in electroplated Cu films with various plating current densities involving direct current and pulse-reverse waveforms and various possible driving forces. Studies have explained the grain growth and resistivity decrease during the self-annealing of as-deposited Cu film, but the incubation behavior of self-annealing under various direct current and pulse-reverse current waveforms at a certain film thickness is unknown. In this study, it was found that pulse-reverse current retards the incubation behavior more significantly than does direct current. According to the measurements of resistivity, stress, and secondary ion mass spectrometer, the large stress difference between the initial and critical values and the low impurity content of pulse-reverse current postponed the incubation, and led to a slow self-annealing rate. The combination of the stress difference and the impurity effect explains the incubation behavior of self-annealing under various plating current densities. The resistivity and X-ray diffraction results suggest that stress is the primary driving force that dramatically speeds up grain growth above the critical stress, and that high current density with a rapid grain growth rate enhances the (200) texture for strain energy minimization in electroplated Cu film.

  9. A simple method of extracting the polarization charge density in the AlGaN/GaN heterostructure from current-voltage and capacitance-voltage characteristics

    International Nuclear Information System (INIS)

    Lü Yuan-Jie; Lin Zhao-Jun; Yu Ying-Xia; Meng Ling-Guo; Cao Zhi-Fang; Luan Chong-Biao; Wang Zhan-Guo

    2012-01-01

    An Ni Schottky contact on the AlGaN/GaN heterostructure is fabricated. The flat-band voltage for the Schottky contact on the AlGaN/GaN heterostructure is obtained from the forward current—voltage characteristics. With the measured capacitance—voltage curve and the flat-band voltage, the polarization charge density in the AlGaN/GaN heterostructure is investigated, and a simple formula for calculating the polarization charge density is obtained and analyzed. With the approach described in this paper, the obtained polarization charge density agrees well with the one calculated by self-consistently solving Schrodinger's and Poisson's equations

  10. Dentists' leadership-related educational experiences, attitudes, and past and current behavior.

    Science.gov (United States)

    Taichman, L Susan; Taichman, Russell S; Inglehart, Marita R

    2014-06-01

    The purpose of this study was to assess practicing dentists' perceptions of their leadership-related educational experiences during predoctoral education and after graduation, to investigate if these perceptions differed as a function of the respondents' graduation year and gender, and to explore the relationships between educational experiences and the respondents' understanding/perceptions of leadership, leadership-related attitudes, self-perceived effectiveness, and past and current leadership- related behavior. Of the 3,000 general dentist members of the American Dental Association who were invited to participate, 593 returned the survey for a response rate of 20 percent. Between 37 and 65 percent of the respondents indicated that their predoctoral dental education had not prepared them well on a series of factors related to being leaders in their practice, community, state, or at the national level. However, 33 to 77 percent of these dentists responded that educational experiences after graduation prepared them well for different types of leadership activities. Overall, respondents rated their predoctoral experiences significantly less positively than their experiences after graduation for each content area. The more recently the respondents had graduated, the higher they rated their leadership-related educational experiences. The better their educational experiences, the more important the respondents evaluated leadership activities in their practice, organized dentistry, and research/teaching, the more important they assessed leadership to be, and the more effective they evaluated themselves to be as leaders. The perceived quality of the respondents' predoctoral education was not correlated with their past and current leadership activities. The results of this study may suggest that improving leadership training during predoctoral education could positively affect future dentists' attitudes about leadership and ratings of their own effectiveness as leaders.

  11. Designing Serious Video Games for Health Behavior Change: Current Status and Future Directions

    OpenAIRE

    Thompson, Debbe

    2012-01-01

    Serious video games for health are designed to entertain while changing a specific health behavior. This article identifies behavioral principles that can guide the development of serious video games focused on changing a variety of health behaviors, including those attempting to decrease risk of obesity and type 2 diabetes. Guidelines discussed include how to develop video games that provide a solid foundation for behavior change by enhancing a player’s knowledge and skill, ways in which per...

  12. Current status of nitrous oxide as a behavior management practice routine in pediatric dentistry.

    Science.gov (United States)

    Levering, Nicholas J; Welie, Jos V M

    2011-01-01

    Nitrous oxide (N(2)O) as a behavioral management intervention in children has attained an excellent safety record and is, therefore, used widely. As is true of any diagnostic or therapeutic dental intervention, however, its usage merits periodic review, even if-or particularly when-it is routinely applied. For example, when N(2)O is used in combination with other sedatives, such polypharmacy can produce potentially serious side effects. There are also bioenvironmental risks to patients and staff if ambient air is not properly monitored. Using historical publications, current empirical articles, professional usage policies, and educational textbooks, the purpose of this article was to review indications and contraindications of N(2)O and discuss various factors that should or should not be considered about its use in the United States. Even though today's parents may be more accepting of pharmacologic approaches such as N(2)O, the choice to use it should always be made with the child's best interest in mind.

  13. Designing serious video games for health behavior change: Current status and future directions

    Science.gov (United States)

    Serious video games for health are designed to entertain while changing a specific health behavior. This article identifies behavioral principles that can guide the development of serious video games focused on changing a variety of health behaviors, including those attempting to decrease risk of o...

  14. Current-use pesticides in seawater and their bioaccumulation in polar bear-ringed seal food chains of the Canadian Arctic.

    Science.gov (United States)

    Morris, Adam D; Muir, Derek C G; Solomon, Keith R; Letcher, Robert J; McKinney, Melissa A; Fisk, Aaron T; McMeans, Bailey C; Tomy, Gregg T; Teixeira, Camilla; Wang, Xiaowa; Duric, Mark

    2016-07-01

    The distribution of current-use pesticides (CUPs) in seawater and their trophodynamics were investigated in 3 Canadian Arctic marine food chains. The greatest ranges of dissolved-phase concentrations in seawater for each CUP were endosulfan sulfate (less than method detection limit (MDL) to 19 pg L(-1) ) > dacthal (0.76-15 pg L(-1) ) > chlorpyrifos (less than MDL to 8.1 pg L(-1) ) > pentachloronitrobenzene (less than MDL to 2.6 pg L(-1) ) > α-endosulfan (0.20-2.3 pg L(-1) ). Bioaccumulation factors (BAFs, water-respiring organisms) were greatest in plankton, including chlorothalonil (log BAF = 7.4 ± 7.1 L kg(-1) , mean ± standard error), chlorpyrifos (log BAF = 6.9 ± 6.7 L kg(-1) ), and α-endosulfan (log BAF = 6.5 ± 6.0 L kg(-1) ). The largest biomagnification factors (BMFs) were found for dacthal in the capelin:plankton trophic relationship (BMF = 13 ± 5.0) at Cumberland Sound (Nunvavut), and for β-endosulfan (BMF = 16 ± 4.9) and α-endosulfan (BMF = 9.3 ± 2.8) in the polar bear-ringed seal relationship at Barrow and Rae Strait (NU), respectively. Concentrations of endosulfan sulfate exhibited trophic magnification (increasing concentrations with increasing trophic level) in the poikilothermic portion of the food web (trophic magnification factor = 1.4), but all of the CUPs underwent trophic dilution in the marine mammal food web, despite some trophic level-specific biomagnification. Together, these observations are most likely indicative of metabolism of these CUPs in mammals. Environ Toxicol Chem 2016;35:1695-1707. © 2016 SETAC. © 2016 SETAC.

  15. Studies on polar high-speed counter-current chromatographic systems in separation of amaranthine-type betacyanins from Celosia species.

    Science.gov (United States)

    Spórna-Kucab, Aneta; Milo, Angelika; Kumorkiewicz, Agnieszka; Wybraniec, Sławomir

    2018-01-15

    Betacyanins, natural plant pigments exhibiting antioxidant and chemopreventive properties, were extracted from Celosia spicata (Thouars) Spreng. inflorescences and separated by high-speed counter-current chromatography (HSCCC) in two polar solvent systems composed of: TBME - 1-BuOH - ACN - H 2 O (0.7% HFBA, 2:2:1:5, v/v/v/v) (system I) and EtOH - ACN - 1-PrOH - (NH 4 ) 2 SO 4satd.soln - H 2 O (0.5:0.5:0.5:1.2:1, v/v/v/v/v) (system II). The systems were used in the head-to-tail (system I) and tail-to-head (system II) mode. The flow rate of the mobile phase was 2.0 ml/min and the column rotation speed was 860 rpm. The retention of the stationary phase was 73.5% (system I) and 80.0% (system II). For the identification of separated betacyanins in the crude extract as well as in the HSCCC fractions, LC-DAD-ESI-MS/MS analyses were performed. Depending on the target compounds, each of the systems exhibit meaningfully different selectivity and applicability. For the pairs of amaranthines (1/1') and betanins (2/2'), the best choice is the system II, but the acylated amaranthine pairs (3/3' and 4/4') can be resolved only in the ion-pair system I. For the indication of the most suitable solvent system for Celosia plumosa hort., Celosia cristata L. and Celosia spicata (Thouars) Spreng. species, the profiles of betacyanins in different plant parts were studied. Copyright © 2017. Published by Elsevier B.V.

  16. Organic high ionic strength aqueous two-phase solvent system series for separation of ultra-polar compounds by spiral high-speed counter-current chromatography

    Science.gov (United States)

    Zeng, Yun; Liu, Gang; Ma, Ying; Chen, Xiaoyuan; Ito, Yoichiro

    2011-01-01

    Existing two-phase solvent systems for high-speed countercurrent chromatography cover the separation of hydrophobic to moderately polar compounds, but often fail to provide suitable partition coefficient values for highly polar compounds such as sulfonic acids, catecholamines and zwitter ions. The present paper introduces a new solvent series which can be applied for the separation of these polar compounds. It is composed of 1-butanol, ethanol, saturated ammonium sulfate and water at various volume ratios and consists of a series of 10 steps which are arranged according to the polarity of the solvent system so that the two-phase solvent system with suitable K values for the target compound(s) can be found in a few steps. Each solvent system gives proper volume ratio and high density difference between the two phases to provide a satisfactory level of retention of the stationary phase in the spiral column assembly. The method is validated by partition coefficient measurement of four typical polar compounds including methyl green (basic dye), tartrazine (sulfonic acid), tyrosine (zwitter ion) and epinephrine (a catecholamine), all of which show low partition coefficient values in the polar 1-butanol-water system. The capability of the method is demonstrated by separation of three catecholamines. PMID:22033108

  17. Developing an Integrated Conceptual Framework of Pro-Environmental Behavior in the Workplace through Synthesis of the Current Literature

    Directory of Open Access Journals (Sweden)

    Faye V. McDonald

    2014-08-01

    Full Text Available Recent studies have begun to bridge the gap between general and workplace pro-environmental behavior by adapting specific existing behavioral models to the workplace environment. This conceptual article proposes a different approach by synthesizing the current general and workplace literature to develop a new model of the antecedents to pro-environmental behavior. Guided by this approach, this paper combines the insights of the current general and workplace models to develop an integrated framework of pro-environmental behavior in the workplace. In doing so, an overview of the current general and workplace literatures will be provided as well as their similarities and differences highlighted. The proposed framework will provide further insights into the antecedents of workplace pro-environmental behavior and identify common findings across the different existing workplace models. This theory can be the basis for further research in order to provide a comprehensive picture of the antecedents of pro-environmental behavior in the workplace. Lastly, implications for specific interventions to develop targeted Human Resource Management practices and work towards achieving environmental sustainability will be discussed.

  18. Current Hormonal Contraceptive Use Predicts Female Extra-Pair and Dyadic Sexual Behavior: Evidence Based on Czech National Survey Data

    Directory of Open Access Journals (Sweden)

    Kateřina Klapilová

    2014-01-01

    Full Text Available Data from 1155 Czech women (493 using oral contraception, 662 non-users, obtained from the Czech National Survey of Sexual Behavior, were used to investigate evolutionary-based hypotheses concerning the predictive value of current oral contraceptive (OC use on extra-pair and dyadic (in-pair sexual behavior of coupled women. Specifically, the aim was to determine whether current OC use was associated with lower extra-pair and higher in-pair sexual interest and behavior, because OC use suppresses cyclical shifts in mating psychology that occur in normally cycling women. Zero-inflated Poisson (ZIP regression and negative binomial models were used to test associations between OC use and these sexual measures, controlling for other relevant predictors (e.g., age, parity, in-pair sexual satisfaction, relationship length. The overall incidence of having had an extra-pair partner or one-night stand in the previous year was not related to current OC use (the majority of the sample had not. However, among the women who had engaged in extra-pair sexual behavior, OC users had fewer one-night stands than non-users, and tended to have fewer partners, than non-users. OC users also had more frequent dyadic intercourse than non-users, potentially indicating higher commitment to their current relationship. These results suggest that suppression of fertility through OC use may alter important aspects of female sexual behavior, with potential implications for relationship functioning and stability.

  19. Current hormonal contraceptive use predicts female extra-pair and dyadic sexual behavior: evidence based on Czech National Survey data.

    Science.gov (United States)

    Klapilová, Kateřina; Cobey, Kelly D; Wells, Timothy; Roberts, S Craig; Weiss, Petr; Havlíček, Jan

    2014-01-10

    Data from 1155 Czech women (493 using oral contraception, 662 non-users), obtained from the Czech National Survey of Sexual Behavior, were used to investigate evolutionary-based hypotheses concerning the predictive value of current oral contraceptive (OC) use on extra-pair and dyadic (in-pair) sexual behavior of coupled women. Specifically, the aim was to determine whether current OC use was associated with lower extra-pair and higher in-pair sexual interest and behavior, because OC use suppresses cyclical shifts in mating psychology that occur in normally cycling women. Zero-inflated Poisson (ZIP) regression and negative binomial models were used to test associations between OC use and these sexual measures, controlling for other relevant predictors (e.g., age, parity, in-pair sexual satisfaction, relationship length). The overall incidence of having had an extra-pair partner or one-night stand in the previous year was not related to current OC use (the majority of the sample had not). However, among the women who had engaged in extra-pair sexual behavior, OC users had fewer one-night stands than non-users, and tended to have fewer partners, than non-users. OC users also had more frequent dyadic intercourse than non-users, potentially indicating higher commitment to their current relationship. These results suggest that suppression of fertility through OC use may alter important aspects of female sexual behavior, with potential implications for relationship functioning and stability.

  20. Influence of direct current on the ageing behavior of a CuCrZr alloy

    OpenAIRE

    Wang, W; Wang, TM.; Zou, CL.; Kang, HJ.; Cao, Zq; Li, Tj

    2015-01-01

    International audience; In recent decades, much work has been done on the effect of electric current on processing and properties of metals. And influence of an electric current on the solid state phase transformation in metals is complicated: an electric current can either enhance or retard the precipitation rate, depending on the alloy composition, the current density and the frequency of pulsed dc current. In this study, we imposed direct current during the ageing process of a CuCrZr alloy...

  1. Self-Monitoring Interventions for Students with Behavior Problems: A Systematic Review of Current Research

    Science.gov (United States)

    Bruhn, Allison; McDaniel, Sara; Kreigh, Christi

    2015-01-01

    Explicitly teaching skills associated with self-determination has been promoted to support students' independence and control over their own lives. This is especially important for students with behavior problems. One self-determination skill or behavior that has been studied widely is self-monitoring. Although multiple reviews of various…

  2. [Analysis of the current situation the oral medical interns' awareness on occupation safety behavior in college].

    Science.gov (United States)

    Hongyan, Song; Yu, Wang; Rongrong, He; Ying, Xu

    2015-04-01

    This study aims to determine the awareness oral medical interns about occupation safety protection of knowledge and to present a scientific basis for perfecting the occupation safety education system and standard protection behavior. A self-designed questionnaire that used a retrospective questionnaire survey on 425 stomatological interns, scoring, and statistical analysis of the survey were performed. The questionnaire included occupation safety prevention knowledge, behavior cognitive, and protective behavior, among others. The questionnaire recovery rate was 100%, and the average scores of the prevention knowledge and behavior cognitive were 4.55 ± 0.91 and 4.40 ± 1.05, respectively. More than 90% interns can conduct the conventional protection, and less than 40% can perform special protection. For the item "occupation safety protection knowledge", the scores of three grade III hospitals were higher than that of stomatological hospitals and second level of first-class hospitals; the difference was statistically significant (P safety protection knowledge, behavioral cognitive, and protection behavior. The average score was higher for than for boys in the three contents, and the average score of interns accepting pre-job training was higher than those rejected; the difference was statistically significant (P safety knowledge of oral medical interns is not sufficient, and the protective behavior is poor. Schools and hospitals should strengthen the intern occupation safety and protection education and improve the status of occupation safety behavior.

  3. Effects of School-Wide Positive Behavior Support on Internalizing Problems: Current Evidence and Future Directions

    Science.gov (United States)

    McIntosh, Kent; Ty, Sophie V.; Miller, Lynn D.

    2014-01-01

    School-wide Positive Behavior Support (SWPBS) has a large evidence base for preventing and addressing externalizing problem behavior, but there is little research examining its effects on internalizing problems, such as anxiety and depression. Given the prevalence of internalizing problems in today's children and youth, it is worthwhile to examine…

  4. The current-voltage relation of a pore and its asymptotic behavior in a Nernst-Planck model

    Directory of Open Access Journals (Sweden)

    Marius Birlea

    2012-08-01

    Full Text Available A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining the electrical behavior of the nanopores in synthetic or biological membranes. Using a Nernst-Planck model, we found three behaviors for the current density in a membrane's pore as a function of voltage: a quasi-ohmic, slow rising linear current at low voltages, a nonlinear current at intermediate voltages, and a non-ohmic, fast rising linear current at large voltages. The slope of the quasi-ohmic current depends mainly on the height of energy barrier inside the pore, w, through an exponential term, ew. The magnitude of the non-ohmic linear current is controlled by the potential energy gradient at the pore entrance, w/r. The current-voltage relation is asymmetric if the ion's potential energy inside the pore has an asymmetric triangular profile. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of the pore, r, which is a useful feature for fitting and interpreting experimental data.

  5. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  6. Polar localization of plasma membrane Ca2+/Mg2+ ATPase correlates with the pattern of steady ionic currents in eggs of Lymnaea stagnalis and Bithynia tentaculata (Mollusca)

    NARCIS (Netherlands)

    D. Zivkovic (Dana); R. Créton (Robbert); G. Zwaan (Gideon); W.C. de Bruijn (Wim); M.R. Dohmen (M.René)

    1990-01-01

    textabstractDuring extrusion of the first polar body in eggs of Lymnaea stagnalis and Bithynia tentaculata a localized Ca2+ /Mg2+ ATPase activity was detected, using Ando's enzyme-cytochemical method for electron microscopy [Ando et al. (1981) Acta Histochem Cytochem 14:705-726]. The enzyme activity

  7. Long-time and large-distance asymptotic behavior of the current-current correlators in the non-linear Schroedinger model

    International Nuclear Information System (INIS)

    Kozlowski, K.K.; Terras, V.

    2010-12-01

    We present a new method allowing us to derive the long-time and large-distance asymptotic behavior of the correlations functions of quantum integrable models from their exact representations. Starting from the form factor expansion of the correlation functions in finite volume, we explain how to reduce the complexity of the computation in the so-called interacting integrable models to the one appearing in free fermion equivalent models. We apply our method to the time-dependent zero-temperature current-current correlation function in the non-linear Schroedinger model and compute the first few terms in its asymptotic expansion. Our result goes beyond the conformal field theory based predictions: in the time-dependent case, other types of excitations than the ones on the Fermi surface contribute to the leading orders of the asymptotics. (orig.)

  8. Designing serious video games for health behavior change: current status and future directions.

    Science.gov (United States)

    Thompson, Debbe

    2012-07-01

    Serious video games for health are designed to entertain while changing a specific health behavior. This article identifies behavioral principles that can guide the development of serious video games focused on changing a variety of health behaviors, including those attempting to decrease risk of obesity and type 2 diabetes. Guidelines discussed include how to develop video games that provide a solid foundation for behavior change by enhancing a player's knowledge and skill, ways in which personal mastery experiences can be incorporated into a video game environment, using game characters and avatars to promote observational learning, creating personalized experiences through tailoring, and the importance of achieving a balance between "fun-ness" and "seriousness." The article concludes with suggestions for future research needed to inform this rapidly growing field. © 2012 Diabetes Technology Society.

  9. Effect of gate voltage polarity on the ionic liquid gating behavior of NdNiO3/NdGaO3 heterostructures

    Directory of Open Access Journals (Sweden)

    Yongqi Dong

    2017-05-01

    Full Text Available The effect of gate voltage polarity on the behavior of NdNiO3 epitaxial thin films during ionic liquid gating is studied using in situ synchrotron X-ray techniques. We show that while negative biases have no discernible effect on the structure or composition of the films, large positive gate voltages result in the injection of a large concentration of oxygen vacancies (∼3% and pronounced lattice expansion (0.17% in addition to a 1000-fold increase in sheet resistance at room temperature. Despite the creation of large defect densities, the heterostructures exhibit a largely reversible switching behavior when sufficient time is provided for the vacancies to migrate in and out of the thin film surface. The results confirm that electrostatic gating takes place at negative gate voltages for p-type complex oxides while positive voltages favor the electrochemical reduction of Ni3+. Switching between positive and negative gate voltages therefore involves a combination of electronic and ionic doping processes that may be utilized in future electrochemical transistors.

  10. Current Methods in Health Behavior Research Among U.S. Community College Students: A Review of the Literature.

    Science.gov (United States)

    Pokhrel, Pallav; Little, Melissa A; Herzog, Thaddeus A

    2014-06-01

    The majority of health behavior research involving college students in the United States has focused on 4-year college students. Two-year or community college students have been less studied, although a significant proportion of U.S. undergraduates, primarily those from disadvantaged socioeconomic and/or racial/ethnic background, are enrolled in community colleges. Thus, there is a need to enhance health behavior and health promotion research among community college students. This study systematically reviewed 42 published, peer-reviewed health behavior studies conducted among U.S. community college students in order to determine the current state of research in the area with regard to behaviors studied, research designs used, recruitment and data collection strategies practiced, rates of student participation, and characteristics of the participants represented. Findings identified the methodological limitations of current research and suggested optimal recruitment and data collection methods suitable for various research needs. Findings are discussed in the context of enhancing health behavior research among U.S. community college students. © The Author(s) 2013.

  11. Does early family risk and current quality of care predict indiscriminate social behavior in institutionalized Portuguese children?

    Science.gov (United States)

    Soares, Isabel; Belsky, Jay; Oliveira, Paula; Silva, Joana; Marques, Sofia; Baptista, Joana; Martins, Carla

    2014-01-01

    The current study extends research on the effects of institutionalization, most notably by evaluating the influence of proximal relationship processes over and above prenatal and pre-institutional family experiences. By focusing on current quality of institutional care and the child's early family background, it examines the influence of variations in the institutionalization experience on displays of indiscriminate social behavior, after taking into account potentially confounding pre-admission experiences. Seventy-four Portuguese children (11-30 months) placed in 17 residential institutions and their primary caregivers participated in the study. Children's displays of indiscriminate social behavior were assessed based on an observational measure and a semi-structured interview administered to the child's caregiver. Data on children's physical and mental development were also collected. Three contextual-risk composites of early family behavior - prenatal, family relational, and emotional-neglect--were created. The quality of institutional care was examined in terms of structural, relational characteristics, and, additionally, of the quality of child-caregiver relationship. Current quality of care experienced in the institution, operationalized in terms of the absence (vs. presence) of a preferred caregiver, predicted indiscriminate social behavior over and above prenatal and family risk conditions that preceded the child's institutionalization.

  12. Behavior of AC High Voltage Polyamide Insulators: Evolution of Leakage Current in Different Surface Conditions

    Directory of Open Access Journals (Sweden)

    Mohammed El Amine Slama

    2015-01-01

    Full Text Available This paper is aimed at a systematic study of the leakage current of high voltage polyamide insulator string under different conditions of pollution for possible application in the electric locomotive systems. It is shown that in the case of clean/dry and clean/wetted insulators, the leakage current and applied voltage are linear. While in the case of pollution with saline spray, the leakage current and the applied voltage are not linear; the leakage current changes from a linear regime to a nonlinear regime up to total flashover of the insulators sting. Traces of erosion and tracking of insulators resulting of partial discharges are observed.

  13. Polarization, political

    NARCIS (Netherlands)

    Wojcieszak, M.; Mazzoleni, G.; Barnhurst, K.G.; Ikeda, K.; Maia, R.C.M.; Wessler, H.

    2015-01-01

    Polarization has been studied in three different forms: on a social, group, and individual level. This entry first focuses on the undisputed phenomenon of elite polarization (i.e., increasing adherence of policy positions among the elites) and also outlines different approaches to assessing mass

  14. Phenomenological theory of current-producing processes at the solid oxide electrolyte/gas electrode interface: steady-state polarization of fuel-cell electrodes

    International Nuclear Information System (INIS)

    Murygin, I.V.; Chebotin, V.N.

    1979-01-01

    The polarization of fuel-cell electrodes (mixtures CO + CO 2 and H 2 + H 2 O) in systems with solid oxide electrolytes is discussed. The theory is based upon a process model where the electrode reaction zone can spread along the line of three-phase contact by diffusion of reaction partners and products across the electrolyte/electrode and electrolyte/gas interface

  15. Monophasic Pulsed 200-μA Current Promotes Galvanotaxis With Polarization of Actin Filament and Integrin α2β1 in Human Dermal Fibroblasts.

    Science.gov (United States)

    Uemura, Mikiko; Maeshige, Noriaki; Koga, Yuka; Ishikawa-Aoyama, Michiko; Miyoshi, Makoto; Sugimoto, Masaharu; Terashi, Hiroto; Usami, Makoto

    2016-01-01

    The monophasic pulsed microcurrent is used to promote wound healing, and galvanotaxis regulation has been reported as one of the active mechanisms in the promotion of tissue repair with monophasic pulsed microcurrent. However, the optimum monophasic pulsed microcurrent parameters and intracellular changes caused by the monophasic pulsed microcurrent have not been elucidated in human dermal fibroblasts. The purpose of this study was to investigate the optimum intensity for promoting galvanotaxis and the effects of electrical stimulation on integrin α2β1 and actin filaments in human dermal fibroblasts. Human dermal fibroblasts were treated with the monophasic pulsed microcurrent of 0, 100, 200, or 300 μA for 8 hours, and cell migration and cell viability were measured 24 hours after starting monophasic pulsed microcurrent stimulation. Polarization of integrin α2β1 and lamellipodia formation were detected by immunofluorescent staining 10 minutes after starting monophasic pulsed microcurrent stimulation. The migration toward the cathode was significantly higher in the cells treated with the 200-μA monophasic pulsed microcurrent than in the controls (P microcurrent did not alter the migration ratio. The electrostimulus of 200 μA also promoted integrin α2β1 polarization and lamellipodia formation at the cathode edge (P microcurrent intensity to promote migration toward the cathode, and this intensity could regulate polarization of migration-related intracellular factors in human dermal fibroblasts.

  16. Sociodemographic, Behavioral, and Psychological Correlates of Current Overweight and Obesity in Older, Urban African American Women

    Science.gov (United States)

    Patt, Madhavi Reddy; Yanek, Lisa R.; Moy, Taryn F.; Becker, Diane M.

    2004-01-01

    To better understand obesity and overweight among urban African American women, the authors examined sociodemographic, behavioral, and psychological factors within body mass index (BMI) categories. A total of 496 women were recruited for cardiovascular risk factor screening from 20 urban African American churches. Study participants had a mean age…

  17. Pharmacotherapy of Disruptive Behavior in Mentally Retarded Subjects: A Review of the Current Literature

    Science.gov (United States)

    Hassler, Frank; Reis, Olaf

    2010-01-01

    The review presented here describes the state of the art of pharmacological treatment of aggression in subjects with mental retardation (MR) summing up results for both, children and adults. In general, psychopharmacological treatment of disruptive behavior in individuals with MR is similar to the treatment in subjects without MR. Compared to…

  18. A Look at Current Validity Issues of School-Wide Behavior Support

    Science.gov (United States)

    Kern, Lee; Manz, Patricia

    2004-01-01

    School-wide behavior support has experienced recent interest among educators. This approach has been embraced because of its potential for decreasing school violence and improving school climate. In this paper we examine issues related to construct, internal, external, and social validity of school-wide support as it has been conceptualized in…

  19. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  20. Repeated Transcranial Direct Current Stimulation Induces Behavioral, Metabolic and Neurochemical Effects in Rats on High-Calorie Diet

    OpenAIRE

    Agata Ziomber; Eugeniusz Rokita; Jolanta Kaszuba-Zwoinska; Irena Romańska; Jerzy Michaluk; Lucyna Antkiewicz-Michaluk

    2018-01-01

    Due to its high prevalence, obesity is considered an epidemic, which stimulated research on non-invasive methods to reduce excess body fat. Transcranial direct current stimulation (tDCS) is a non-invasive technique used to modulate the activity of cerebral cortex, which has already found increasing interest in medicine as a promising methodology. The aim of this study was to analyze the impact of tDCS on feeding behavior, metabolic abnormalities and neurotransmitters in certain brain areas in...

  1. Effect of Postweld Aging Treatment on Fatigue Behavior of Pulsed Current Welded AA7075 Aluminum Alloy Joints

    Science.gov (United States)

    Balasubramanian, V.; Ravisankar, V.; Madhusudhan Reddy, G.

    2008-04-01

    This article reports the effect of postweld aging treatment on fatigue behavior of pulsed current welded AA 7075 aluminum alloy joints. AA7075 aluminum alloy (Al-Zn-Mg-Cu alloy) has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to weight ratio, such as transportable bridge girders, military vehicles, road tankers, and railway transport systems. The preferred welding processes of AA7075 aluminum alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Rolled plates of 10 mm thickness have been used as the base material for preparing multipass welded joints. Single V butt joint configuration has been prepared for joining the plates. The filler metal used for joining the plates is AA 5356 (Al-5Mg (wt.%)) grade aluminum alloy. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW), and (iv) pulsed current GMAW (PCGMAW) processes. Argon (99.99% pure) has been used as the shielding gas. Rotary bending fatigue testing machine has been used to evaluate fatigue behavior of the welded joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. Grain refinement is accompanied by an increase in fatigue life and endurance limit. Simple postweld aging treatment applied to the joints is found to be beneficial to enhance the fatigue performance of the welded joints.

  2. The Effect of Short Duration Electric Current on the Quasi-Static Tensile Behavior of Magnesium AZ31 Alloy

    Directory of Open Access Journals (Sweden)

    Trung Thien Nguyen

    2016-01-01

    Full Text Available The effect of a single pulse of electric current with short duration on the quasi-static tensile behavior of a magnesium AZ31 alloy is experimentally investigated. A single pulse of electric current with duration less than 1 second is applied to the specimen, while the specimen is being deformed in the plastic region under quasi-static tensile loads. After a nearly instant decrease of flow stress at the pulse of electric current, the flow stress shows strain hardening until the failure of the specimen. The experimental result shows that the strain-hardening parameters (the strength coefficient and the strain-hardening exponent of the hardening curve after the electric current strongly depend on the applied electric energy density (electric energy per unit volume. Empirical expressions are suggested to describe the hardening behavior after the pulse as a function of the electric energy density and are compared with the empirical expressions suggested for advanced high-strength steels.

  3. Notas sobre o Behaviorismo de ontem e de hoje Remarks on former and current Behaviorism

    Directory of Open Access Journals (Sweden)

    Emmanuel Zagury Tourinho

    2011-01-01

    Full Text Available Este artigo busca oferecer algumas referências históricas sobre as origens e desenvolvimentos da Psicologia behaviorista. O artigo parte das contribuições de Watson, destacando seu afastamento do modo causal selecionista, inaugurado na Psicologia por Thorndike. Em seguida, discute alguns desenvolvimentos do behaviorismo sob a liderança de Skinner, apontando que seus avanços resultam em grande medida do retorno ao selecionismo. O artigo argumenta, por fim, que ao final do século XX a abordagem inaugurada por Skinner estende-se a em muitas direções, configurando a análise do comportamento como um sistema multidimensional. O artigo conclui com a indicação de que uma visão histórica do processo de investigação comportamental oferece um quadro mais preciso do que essa abordagem tem representado enquanto sistema na Psicologia.This paper aims at offering some historical references concerning the origins and development of behaviorist Psychology. It begins with Watson's contributions and highlights his detachment from the causal mode of selection by consequence started in Psychology by Thorndike. Then, the paper discusses some developments of behaviorism under the leadership of Skinner and argues that some achievements have largely resulted from a recovery of selectionism. Finally, it contends that, by the end of the 20th century, the approach started by Skinner extended to new directions, engendering behavior analysis as a multidimensional system. The paper concludes by pointing out that a historical view of the process of behavioral investigation provides a more precise frame of what this approach has represented as a psychological system.

  4. Cognitive-behavioral therapy for patients with irritable bowel syndrome: current insights

    Directory of Open Access Journals (Sweden)

    Kinsinger SW

    2017-07-01

    Full Text Available Sarah W Kinsinger Behavioral Medicine for Digestive Health, Division of Gastroenterology and Nutrition, Loyola University Medical Center, Maywood, IL, USA Abstract: Irritable bowel syndrome (IBS is a chronic gastrointestinal (GI condition associated with significant health care utilization and quality-of-life impairment. Latest research indicates that the brain–gut axis plays a key role in the disorder, and the presence of psychological factors and central processing deficits contribute to symptom severity and disability. Psychological therapies as a whole have demonstrated good efficacy in reducing the severity of IBS symptoms. Cognitive-behavioral therapy (CBT has been tested most rigorously in multiple randomized controlled trials and consistently demonstrates significant and durable effects on IBS symptoms and quality of life. Various protocols for treating IBS have been developed, and most recent advances in the field include exposure-based treatments to target symptom-specific anxiety as well as modified delivery methods, including internet-based treatment models. Despite the well-documented advantages of CBT for IBS, it has been poorly disseminated and few patients have access to this treatment. The primary barrier to dissemination is the limited number of therapists with adequate training in GI psychology to provide this evidence-based intervention. Future developments in the field need to focus on training opportunities to equip more therapists to competently provide CBT for this population. Further efforts to develop telemedicine platforms for delivering this intervention will also improve accessibility for patients. Keywords: irritable bowel syndrome, functional gastrointestinal disorders, cognitive-behavioral therapy

  5. Cognitive behavioral therapy to aid weight loss in obese patients: current perspectives

    Directory of Open Access Journals (Sweden)

    Castelnuovo G

    2017-06-01

    Full Text Available Gianluca Castelnuovo,1,2 Giada Pietrabissa,1,2 Gian Mauro Manzoni,1,3 Roberto Cattivelli,1,2 Alessandro Rossi,1 Margherita Novelli,1 Giorgia Varallo,1 Enrico Molinari1,2 1Psychology Research Laboratory, Istituto Auxologico Italiano IRCCS, San Giuseppe Hospital, Verbania, 2Department of Psychology, Catholic University of Milan, Milan, 3Faculty of Psychology, eCampus University, Novedrate, Italy Abstract: Obesity is a chronic condition associated with risk factors for many medical ­complications and comorbidities such as cardiovascular diseases, some types of cancer, osteoarthritis, hypertension, dyslipidemia, hypercholesterolemia, type-2 diabetes, obstructive sleep apnea syndrome, and different psychosocial issues and psychopathological disorders. Obesity is a highly complex, multifactorial disease: genetic, biological, psychological, behavioral, familial, social, cultural, and environmental factors can influence in different ways. Evidence-based strategies to improve weight loss, maintain a healthy weight, and reduce related comorbidities typically integrate different interventions: dietetic, nutritional, physical, behavioral, psychological, and if necessary, pharmacological and surgical ones. Such treatments are implemented in a multidisciplinary context with a clinical team composed of endocrinologists, nutritionists, dietitians, physiotherapists, psychiatrists, psychologists, and sometimes surgeons. Cognitive behavioral therapy (CBT is traditionally recognized as the best established treatment for binge eating disorder and the most preferred intervention for obesity, and could be considered as the first-line treatment among psychological approaches, especially in a long-term perspective; however, it does not necessarily produce a successful weight loss. Traditional CBT for weight loss and other protocols, such as enhanced CBT, enhanced focused CBT, behavioral weight loss treatment, therapeutic education, acceptance and commitment therapy

  6. Cognitive-behavioral therapy for youth with body dysmorphic disorder: current status and future directions.

    Science.gov (United States)

    Phillips, Katharine A; Rogers, Jamison

    2011-04-01

    Body dysmorphic disorder (BDD) usually begins during early adolescence and appears to be common in youth. BDD is characterized by substantial impairment in psychosocial functioning and high rates of suicidality. Cognitive-behavioral therapy (CBT) tailored to BDD is the best tested and most promising psychosocial treatment for adults. CBT has been used for youth with BDD, but has not been systematically developed for or tested in youth. This article focuses on CBT for BDD in adults and youth; possible adaptations and the need for treatment research in youth; and prevalence, clinical features, diagnosis, recommended pharmacotherapy, and treatments that are not recommended. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Neuroimaging studies of aggressive and violent behavior: current findings and implications for criminology and criminal justice.

    Science.gov (United States)

    Bufkin, Jana L; Luttrell, Vickie R

    2005-04-01

    With the availability of new functional and structural neuroimaging techniques, researchers have begun to localize brain areas that may be dysfunctional in offenders who are aggressive and violent. Our review of 17 neuroimaging studies reveals that the areas associated with aggressive and/or violent behavioral histories, particularly impulsive acts, are located in the prefrontal cortex and the medial temporal regions. These findings are explained in the context of negative emotion regulation, and suggestions are provided concerning how such findings may affect future theoretical frameworks in criminology, crime prevention efforts, and the functioning of the criminal justice system.

  8. Effects of doping on ferroelectric properties and leakage current behavior of KNN-LT-LS thin films on SrTiO3 substrate

    Science.gov (United States)

    Abazari, M.; Safari, A.

    2009-05-01

    We report the effects of Ba, Ti, and Mn dopants on ferroelectric polarization and leakage current of (K0.44Na0.52Li0.04)(Nb0.84Ta0.1Sb0.06)O3 (KNN-LT-LS) thin films deposited by pulsed laser deposition. It is shown that donor dopants such as Ba2+, which increased the resistivity in bulk KNN-LT-LS, had an opposite effect in the thin film. Ti4+ as an acceptor B-site dopant reduces the leakage current by an order of magnitude, while the polarization values showed a slight degradation. Mn4+, however, was found to effectively suppress the leakage current by over two orders of magnitude while enhancing the polarization, with 15 and 23 μC/cm2 remanent and saturated polarization, whose values are ˜70% and 82% of the reported values for bulk composition. This phenomenon has been associated with the dual effect of Mn4+ in KNN-LT-LS thin film, by substituting both A- and B-site cations. A detailed description on how each dopant affects the concentrations of vacancies in the lattice is presented. Mn-doped KNN-LT-LS thin films are shown to be a promising candidate for lead-free thin films and applications.

  9. Kramers-Kronig relations for interstellar polarization

    International Nuclear Information System (INIS)

    Martin, P.G.

    1975-01-01

    The difficulties encountered in using the Kramers-Kronig relations to predict the behavior of interstellar polarization are pointed out, while at the same time their value in an interpretive role is acknowledged. Observations of interstellar circular polarization lead to restrictions on the interstellar grain composition, and additional constraints should be possible through measurement of linear polarization in the infrared and the ultraviolet

  10. Molecular Dynamics Study of the Separation Behavior at the Interface between PVDF Binder and Copper Current Collector

    Directory of Open Access Journals (Sweden)

    Seungjun Lee

    2016-01-01

    Full Text Available In Li-ion batteries, the mechanical strengths at the interfaces of binder/particle and binder/current collector play an important role in maintaining the mechanical integrity of the composite electrode. In this work, the separation behaviors between polyvinylidene fluoride (PVDF binders and copper current collectors are studied in the opening and sliding modes using molecular dynamics (MD simulations. The simulation shows that the separation occurs inside the PVDF rather than at the interface due to the strong adhesion between PVDF and copper. This fracture behavior is different from the behavior of the PVDF/graphite basal plane that shows a clear separation at the interface. The results suggest that the adhesion strength of the PVDF/copper is stronger than that of the PVDF/graphite basal plane. The methodology used in MD simulation can directly evaluate the adhesion strength at the interfaces of various materials between binders, substrates, and particles at the atomic scales. The proposed method can therefore provide a guideline for the design of the electrode in order to enhance the mechanical integrity for better battery performance.

  11. No More Polarization, Please!

    DEFF Research Database (Denmark)

    Hansen, Mia Reinholt

    The organizational science literature on motivation has for long been polarized into two main positions; the organizational economic position focusing on extrinsic motivation and the organizational behavior position emphasizing intrinsic motivation. With the rise of the knowledge economy...... and the increasing levels of complexities it entails, such polarization is not fruitful in the attempt to explain motivation of organizational members. This paper claims that a more nuanced perspective on motivation, acknowledging the co-existence of intrinsic and extrinsic motivation, the possible interaction...... between the two as well as different types of motivations filling in the gap between the two polar types, is urgently needed in the organizational science literature. By drawing on the research on intrinsic and extrinsic motivation conducted in social psychology and combining this with contributions from...

  12. Effects of Current on Behaviors of Saturated Magnetic Island in Tokamak

    International Nuclear Information System (INIS)

    Kanjanaput, W.; Picha, R.; Promping, J.; Poolyarat, N.; Onjun, T.

    2014-01-01

    Plasma current density gradient is known to be one of crucial parameters triggering neoclassical tearing mode in a tokamak plasma. This kind of instability can lead to a formation of magnetic islands, which results in the reduction of plasma pressure and, consequently the degradation of fusion performance. The ISLAND module, developed for determining multiple saturated island width due to different unstable modes, is used in this work. This calculation is based on a quasi-linear theory approach and can include the effect of the bootstrap cur- rent. Both geometry of tokamak and the operation conditions such as magnetic field strength, current and pressure profile are used as initial inputs. The different unstable modes (called m/n, where m and n are the poloidal and toroidal mode number, respectively) are considered. It is found in this work that the mode m/n =2/1 is found to produce the largest saturated island width in the JET and DIIID tokamaks, which agrees with what observed in those to- kamaks. The saturated width of this mode trends to get larger when the gradient of current between the magnetic axis and the mode rational surface increase. The detailed results will be investigated and discussed.

  13. On/off-current Ratio and Ambipolar Behavior of Narrow Bandgap III-V Nanowire FETs

    Science.gov (United States)

    Zhao, Yanjie; Candebat, Drew; Delker, Collin; Zi, Yunlong; Janes, David; Appenzeller, Joerg; Yang, Chen

    2013-03-01

    III-V nanowires (NW) are promising candidates for future device applications due to the high bulk mobility. Yet the small bandgap may result in undesirable high off-current. Here we establish a simple but reliable model that quantitatively explains how channel bandgap and Schottky barriers at metal contacts affect the ambipolar characteristics and the achievable on/off-current ratios of NW-FETs. Thus one can gain insights of the expected transfer characteristics of a given channel material with certain device structure, and the optimal choice of materials for different device applications in ultimately scaled cases. The physics of electron transport in both ideal case (no Schottky barrier) and practical case (with Schottky barrier) is studied. The impact of Schottky barriers is evaluated by numerical calculation of the tunneling current, and is found to play a critical role for the different characteristics observed. A universal plot of on/off ratio vs. bandgap is presented. The excellent agreement between our simulation predictions and experiment results from InAs, InSb, Ge NWs and CNTs highlights the potential of our approach for understanding narrow bandgap NW-FETs, bridging material development and device applications, and guiding future transistor design.

  14. Single trap in liquid gated nanowire FETs: Capture time behavior as a function of current

    Science.gov (United States)

    Gasparyan, F.; Zadorozhnyi, I.; Vitusevich, S.

    2015-05-01

    The basic reason for enhanced electron capture time, τ c , of the oxide single trap dependence on drain current in the linear operation regime of p+-p-p+ silicon field effect transistors (FETs) was established, using a quantum-mechanical approach. A strong increase of τ c slope dependence on channel current is explained using quantization and tunneling concepts in terms of strong field dependence of the oxide layer single trap effective cross-section, which can be described by an amplification factor. Physical interpretation of this parameter deals with the amplification of the electron cross-section determined by both decreasing the critical field influence as a result of the minority carrier depletion and the potential barrier growth for electron capture. For the NW channel of n+-p-n+ FETs, the experimentally observed slope of τ c equals (-1). On the contrary, for the case of p+-p-p+ Si FETs in the accumulation regime, the experimentally observed slope of τ c equals (-2.8). It can be achieved when the amplification factor is about 12. Extraordinary high capture time slope values versus current are explained by the effective capture cross-section growth with decreasing electron concentration close to the nanowire-oxide interface.

  15. Current state of the construction of SPARC test facility for observing hydrogen′s behavior

    Energy Technology Data Exchange (ETDEWEB)

    Na, Young Su; Hong, Seong-Ho; Park, Ki Han; Hong, Seong-Wan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Hydrogen combustion can make a dynamic load, which can cause severe damage to a structure or facility. Many studies on hydrogen behavior, such as distribution, combustion and mitigation, have been conducted since the TMI accident, and they were recently summarized in. A large-scaled experimental facility is required for simulating the complex severe accident phenomena in a closed containment building. We are preparing the test facility, called the SPARC (Spray, Aerosol, Recombiner, Combustion), to resolve the international open issues regarding hydrogen risk as well as the validation of the Korean PAR (Passive Auto-catalytic Recombiner). This paper summarized the previous study submitted to the NUTHOS-11, which introduced the SPARC test facility. KAERI (Korea Atomic Energy Research Institute) is preparing a test facility, called the SPARC for an assessment of the containment integrity under a severe accident. In the SPARC test facility, the hydrogen behavior such as mixing with steam and air, distribution, and combustion will be observed under various thermal-hydraulic conditions. We will carry out the performance tests of the safety systems such as the spray, cooling fan, PAR, and igniter. The SPARC test facility consists of a pressure vessel with a 9.5 m height and 3.4 m diameter, and an operating system to control and measure the thermal hydraulic conditions. In a commissioning test, we verified the controllable thermal conditions. It took about 8,400 seconds to increase up to 5 bar. The increment rate of the atmosphere temperature is about 34° C/h from room temperature to 100° C.

  16. A circumpolar monitoring framework for polar bears

    Science.gov (United States)

    Vongraven, Dag; Aars, Jon; Amstrup, Steven C.; Atkinson, Stephen N.; Belikov, Stanislav; Born, Erik W.; DeBruyn, T.D.; Derocher, Andrew E.; Durner, George M.; Gill, Michael J.; Lunn, Nicholas J.; Obbard, Martyn E.; Omelak, Jack; Ovsyanikov, Nikita; Peacock, Elizabeth; Richardson, E.E.; Sahanatien, Vicki; Stirling, Ian; Wiig, Øystein

    2012-01-01

    Polar bears (Ursus maritimus) occupy remote regions that are characterized by harsh weather and limited access. Polar bear populations can only persist where temporal and spatial availability of sea ice provides adequate access to their marine mammal prey. Observed declines in sea ice availability will continue as long as greenhouse gas concentrations rise. At the same time, human intrusion and pollution levels in the Arctic are expected to increase. A circumpolar understanding of the cumulative impacts of current and future stressors is lacking, long-term trends are known from only a few subpopulations, and there is no globally coordinated effort to monitor effects of stressors. Here, we describe a framework for an integrated circumpolar monitoring plan to detect ongoing patterns, predict future trends, and identify the most vulnerable polar bear subpopulations. We recommend strategies for monitoring subpopulation abundance and trends, reproduction, survival, ecosystem change, human-caused mortality, human–bear conflict, prey availability, health, stature, distribution, behavioral change, and the effects that monitoring itself may have on polar bears. We assign monitoring intensity for each subpopulation through adaptive assessment of the quality of existing baseline data and research accessibility. A global perspective is achieved by recommending high intensity monitoring for at least one subpopulation in each of four major polar bear ecoregions. Collection of data on harvest, where it occurs, and remote sensing of habitat, should occur with the same intensity for all subpopulations. We outline how local traditional knowledge may most effectively be combined with the best scientific methods to provide comparable and complementary lines of evidence. We also outline how previously collected intensive monitoring data may be sub-sampled to guide future sampling frequencies and develop indirect estimates or indices of subpopulation status. Adoption of this framework

  17. The SLAC polarized electron source

    International Nuclear Information System (INIS)

    Tang, H.; Alley, R.; Frisch, J.

    1995-06-01

    The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of ≥80% and a peak current exceeding 10 A. Its operating efficiency has reached 99%. The physics and technology of producing high polarization electron beams from a GaAs photocathode will be reviewed. The prospects of realizing a polarized electron source for future linear colliders will also be discussed

  18. Evaluation of mechanical and optical behavior of current esthetic dental restorative CAD/CAM composites.

    Science.gov (United States)

    Stawarczyk, Bogna; Liebermann, Anja; Eichberger, Marlis; Güth, Jan-Frederik

    2015-03-01

    To determine the mechanical and optical properties of CAD/CAM composites (LAVA Ultimate, Cerasmart, Shofu Block and two exp. CAD/CAM composites), a hybrid material (VITA Enamic), a leucite (IPS Empress CAD) and a lithium disilicate glass-ceramic (IPS e.max CAD). Three-point flexural strength (FS) was investigated according ISO 6872:2008 (N=240/n=30). Two-body wear (TBW) was analyzed in a chewing simulator (1,200,000 cycles, 50N, 5°/55°C) using human teeth as antagonists (N=120/n=15). Quantitative analysis of wear was carried out with a 3D-scanner and associated matching software. Discoloration rate (DR) after 14 days of storage in cress, curry, red wine, and distilled water (N=384/n=12), and translucency (T) (N=384/n=48) of CAD/CAM materials were measured in a spectrophotometer (400-700nm wavelength). Data were analyzed using two-/one-way ANOVA with Scheffé post-hoc test, Kruskal-Wallis-H test, and linear mixed models (α=0.05). IPS e.max CAD showed the highest FS (pCAD/CAM composites (exception: Shofu Block). The lowest FS showed VITA Enamic and IPS Empress CAD (pCAD, VITA Enamic, exp. CAD/CAM composite 2, followed by IPS e.max presented lower material TBW than the remaining CAD/CAM materials (pcurry>cress>distilled water) exerted the highest influence on DR (pCAD/CAM material. Glass-ceramics showed lower DR than CAD/CAM composites (pCAD/CAM composites presented moderate FS, high T and antagonist friendly behavior. Glass-ceramic demonstrated the most favorable DR and lowest TBW on the material side. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. AGS polarized H- source

    International Nuclear Information System (INIS)

    Kponou, A.; Alessi, J.G.; Sluyters, T.

    1985-01-01

    The AGS polarized H - source is now operational. During a month-long experimental physics run in July 1984, pulses equivalent to 15 μA x 300 μs (approx. 3 x 10 10 protons) were injected into the RFQ preaccelerator. Beam polarization, measured at 200 MeV, was approx. 75%. After the run, a program to increase the H - yield of the source was begun and significant progress has been made. The H - current is now frequently 20 to 30 μA. A description of the source and some details of our operating experience are given. We also briefly describe the improvement program

  20. Optically pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Anderson, L.W.

    1986-01-01

    The current status and future prospects for the optically pumped polarized H - ion source are discussed. At the present time H - ion currents of 60 μA and with a polarization of 65% have been produced. The ion current and polarization can be increased significantly if the optically pumped Na charge exchange target density and polarization can be increased. Studies of wall surfaces that permit many bounces before depolarizing the Na electron spin and studies of radiation trapping in optically pumped Na indicate that the Na target density and polarization can be increased substantially. 27 refs., 6 figs., 2 tabs

  1. Ecosystem scenarios shape fishermen spatial behavior. The case of the Peruvian anchovy fishery in the Northern Humboldt Current System

    Science.gov (United States)

    Joo, Rocio; Bertrand, Arnaud; Bouchon, Marilu; Chaigneau, Alexis; Demarcq, Hervé; Tam, Jorge; Simier, Monique; Gutiérrez, Dimitri; Gutiérrez, Mariano; Segura, Marceliano; Fablet, Ronan; Bertrand, Sophie

    2014-11-01

    A major goal in marine ecology is the understanding of the interactions between the dynamics of the different ecosystem components, from physics to top predators. While fishermen are among the main top predators at sea, almost none of the existing studies on ecology from physics to top predators contemplate fishermen as part of the system. The present work focuses on the coastal processes in the Northern Humboldt Current System, which encompasses both an intense climatic variability and the largest monospecific fishery of the world. From concomitant satellite, acoustic survey and Vessel Monitoring System data (∼90,000 fishing trips) for a ten-year period (2000-2009), we quantify the associations between the dynamics of the spatial behavior of fishermen, environmental conditions and anchovy (Engraulis ringens) biomass and spatial distribution. Using multivariate statistical analyses we show that environmental and anchovy conditions do significantly shape fishermen spatial behavior and present evidences that environmental fluctuations smoothed out along trophic levels. We propose a retrospective analysis of the study period in the light of the ecosystem scenarios evidenced and we finally discuss the potential use of fishermen spatial behavior as ecosystem indicator.

  2. Political polarization

    OpenAIRE

    Dixit, Avinash K.; Weibull, Jörgen W.

    2007-01-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  3. Political polarization.

    Science.gov (United States)

    Dixit, Avinash K; Weibull, Jörgen W

    2007-05-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  4. Cognitive-behavior therapy for problem gambling: a critique of current treatments and proposed new unified approach.

    Science.gov (United States)

    Tolchard, Barry

    2017-06-01

    There is evidence supporting the use of cognitive-behavioral therapy (CBT) in the treatment of problem gambling. Despite this, little is known about how CBT works and which particular approach is most effective. This paper aims to synthesize the evidence for current CBT and propose a more unified approach to treatment. A literature review and narrative synthesis of the current research evidence of CBT for the treatment of problem gambling was conducted, focusing on the underlying mechanisms within the treatment approach. Several CBT approaches were critiqued. These can be divided into forms of exposure therapy (including aversion techniques, systematic desensitization and other behavioral experiments) those focusing on cognitive restructuring techniques (such as reinforcement of nongambling activity, use of diaries, motivational enhancement and audio-playback techniques and third wave techniques including mindfulness. Findings, in relation to the treatment actions, from this synthesis are reported. The debate surrounding the treatment of problem gambling has been conducted as an either/or rather than a both/and discourse. This paper proposes a new, unified approach to the treatment of problem gambling that incorporates the best elements of both exposure and cognitive restructuring techniques, alongside the use of techniques borrowed from mindfulness and other CBT approaches.

  5. The behavior of a type-II superconductor Nb in a magnetic field as investigated in polarized-neutron transmission experiments

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Dokukin, E.B.; Kozhevnikov, S.V.; Nikitenko, Yu.V.; Petrenko, A.V.

    1995-01-01

    The type-II superconducting polycrystal Nb was investigated on the SPN-1 polarized-neutron spectrometer at the high-intensity pulsed reactor IBR-2 at Dubna. In polarized-neutron transmission experiments the magnetic-field dependence of the neutron beam polarization was measured. Experiments were performed over a wide magnetic-field range from 0 to H c2 at a temperature of 4.8 K. A quasiperiodic variation of the neutron depolarization as a function of magnetic-field strength was observed. (orig.)

  6. The Bochum Polarized Target

    International Nuclear Information System (INIS)

    Reicherz, G.; Goertz, S.; Harmsen, J.; Heckmann, J.; Meier, A.; Meyer, W.; Radtke, E.

    2001-01-01

    The Bochum 'Polarized Target' group develops the target material 6 LiD for the COMPASS experiment at CERN. Several different materials like alcohols, alcanes and ammonia are under investigation. Solid State Targets are polarized in magnetic fields higher than B=2.5T and at temperatures below T=1K. For the Dynamic Nuclear Polarization process, paramagnetic centers are induced chemically or by irradiation with ionizing beams. The radical density is a critical factor for optimization of polarization and relaxation times at adequate magnetic fields and temperatures. In a high sensitive EPR--apparatus, an evaporator and a dilution cryostat with a continuous wave NMR--system, the materials are investigated and optimized. To improve the polarization measurement, the Liverpool NMR-box is modified by exchanging the fixed capacitor for a varicap diode which not only makes the tuning very easy but also provides a continuously tuned circuit. The dependence of the signal area upon the circuit current is measured and it is shown that it follows a linear function

  7. POLARIZED NEUTRONS IN RHIC

    Energy Technology Data Exchange (ETDEWEB)

    COURANT,E.D.

    1998-04-27

    There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. To accelerate polarized particles in a ring, one must make provisions for overcoming the depolarizing resonances that occur at certain energies. These resonances arise when the spin tune (ratio of spin precession frequency to orbit frequency) resonates with a component present in the horizontal field. The horizontal field oscillates with the vertical motion of the particles (due to vertical focusing); its frequency spectrum is dominated by the vertical oscillation frequency and its modulation by the periodic structure of the accelerator ring. In addition, the magnet imperfections that distort the closed orbit vertically contain all integral Fourier harmonics of the orbit frequency.

  8. Properties and electrochemical behaviors of AuPt alloys prepared by direct-current electrodeposition for lithium air batteries

    International Nuclear Information System (INIS)

    Zhang, Jinqiu; Li, Da; Zhu, Yiming; Chen, Miaomiao; An, Maozhong; Yang, Peixia; Wang, Peng

    2015-01-01

    AuPt catalyst has a prospective application in a lithium air battery because of its bi-function on catalyzing Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER). Electrodeposition is an in-situ convenient technology for catalyst preparation without chemical residue. In an acid electrolyte, AuPt alloy catalysts were electrodeposited on carbon paper. The effect of main salt concentration, electrodeposition time and current density were studied by deposit micromorphology observation, structure analyses and composition testing. Catalytic abilities of AuPt alloys were measured by cyclic voltammetry (CV) in an ionic liquid of EMI-TFSI/Li-TFSI [1- Ethyl - 3- methylimidazolium–bis (trifluoromethanesulphonyl) imide/lithium–bis (trifluoromethanesulphonyl) imide]. The electrochemical behaviors of Au, Pt and AuPt deposits were also measured. An optimized direct-current electrodeposition process of getting high active AuPt catalyst is concluded, which is an aqueous solution containing 6.7∼10 mmol · L −1 HAuCl 4 , 10∼13.3 mmol · L −1 H 2 PtCl 6 and 0.5 mol · L −1 H 2 SO 4 as the electrolyte, current density of 20mA · cm −2 and electrodeposition time of 8∼34 s. The co-deposition of AuPt alloy is an irregular co-deposition controlled by diffusion, while gold atoms enter the platinum’s crystal lattice in the structure of AuPt alloy. The increase of the concentration of H 2 PtCl 6 in the electrolyte, the extension of the electrodeposition time or the raise of the current density can improve the content of Pt in the deposit. The clusters’ diameters of AuPt catalysts decrease to 150∼250 nm by adjusting current densities during electrodeposition

  9. Study on Current Levels of Physical Activity and Sedentary Behavior among Middle School Students in Beijing, China.

    Science.gov (United States)

    Duan, Jiali; Hu, Huanhuan; Wang, Guan; Arao, Takashi

    2015-01-01

    This study aimed to determine current levels of physical activity and sedentary behavior in middle school students on the basis of grade, sex, student attitudes toward physical education, and residence location. In 2013, a cross-sectional study of 1793 students aged 12 to 15 years was conducted across eight middle schools in Beijing, China. Four schools were selected from an urban district and another four schools were from a suburban district. Physical activity and sedentary behavior data were collected using the commonly used school-based Chinese version of the China Health and Nutrition Survey. The mean age of sampled students was 13.3 ± 1.0 years; 51.5% were boys. Approximately 76.6% of students reported having three 45-minute physical education classes every week. A total of 35.6% students spent ≥ 1 h/day performing moderate to vigorous physical activity (MVPA) during school, and 34.9% spent ≥ 1 h/day in MVPA outside school time. Approximately half (49.7%) of the students engaged in reading, writing, or drawing for ≥ 2 h/day, and 42.9% reported screen time for ≥ 2 h/day. Although boys spent more time engaged in physical activity than girls did, they also spent more time exhibiting sedentary behavior. Each 10-unit increase in attitudes toward physical education was associated with an increased odds of 1.15 (95%CI: 1.09-1.20) for spending more than 1 h/day on MVPA. Students in suburban schools reported engaging in physical activity less when compared with those in urban schools. The majority of our students did not meet the current physical activity recommendations, and about half of the students spent excessive time engaging in sedentary behaviors. Findings from this study highlight a positive association between student attitudes toward physical education and physical activity. Studies are needed to further explore the role of student attitudes toward physical education in promoting physical activity among Chinese students.

  10. Study on Current Levels of Physical Activity and Sedentary Behavior among Middle School Students in Beijing, China.

    Directory of Open Access Journals (Sweden)

    Jiali Duan

    Full Text Available This study aimed to determine current levels of physical activity and sedentary behavior in middle school students on the basis of grade, sex, student attitudes toward physical education, and residence location.In 2013, a cross-sectional study of 1793 students aged 12 to 15 years was conducted across eight middle schools in Beijing, China. Four schools were selected from an urban district and another four schools were from a suburban district. Physical activity and sedentary behavior data were collected using the commonly used school-based Chinese version of the China Health and Nutrition Survey.The mean age of sampled students was 13.3 ± 1.0 years; 51.5% were boys. Approximately 76.6% of students reported having three 45-minute physical education classes every week. A total of 35.6% students spent ≥ 1 h/day performing moderate to vigorous physical activity (MVPA during school, and 34.9% spent ≥ 1 h/day in MVPA outside school time. Approximately half (49.7% of the students engaged in reading, writing, or drawing for ≥ 2 h/day, and 42.9% reported screen time for ≥ 2 h/day. Although boys spent more time engaged in physical activity than girls did, they also spent more time exhibiting sedentary behavior. Each 10-unit increase in attitudes toward physical education was associated with an increased odds of 1.15 (95%CI: 1.09-1.20 for spending more than 1 h/day on MVPA. Students in suburban schools reported engaging in physical activity less when compared with those in urban schools.The majority of our students did not meet the current physical activity recommendations, and about half of the students spent excessive time engaging in sedentary behaviors. Findings from this study highlight a positive association between student attitudes toward physical education and physical activity. Studies are needed to further explore the role of student attitudes toward physical education in promoting physical activity among Chinese students.

  11. Characterization of Elastic and Plastic Behaviors in Steel Plate Based on Eddy Current Technique Using a Portable Impedance Analyzer

    Directory of Open Access Journals (Sweden)

    Meng Fanlin

    2017-01-01

    Full Text Available A portable impedance analyzer (PIA was developed based on a TiePie-HS3 device to provide the comparable impedance measurement accuracy of the Agilent 4294a impedance analyzer in the frequency range of 0~250 kHz. Then the PIA was applied to monitor the tensile stress-induced variation of the eddy current sensor’s impedance in a medium-carbon steel sample. A model of equivalent magnetic field induced by the elastic stress and the number of pinning sites indicated that the inductance of the eddy current loop firstly increased with the increase in the tensile stress and then decreased at the yield point of the material. The experimental results testified that the variation of impedance amplitude, the variation of phase angle, and the shift of two featured frequencies demonstrated opposite variation trends before and after the yield point, as predicated by the model. A new parameter, which combined the impedance variation information of the selected two frequencies, was found to exhibit nearly monotonous dependency on the tensile stress in elastic and plastic stages. The new parameter together with the developed portable impedance analyzer provided the solution to identify the elastic and plastic behaviors in ferromagnetic materials in practical applications with an eddy current technique.

  12. Experimental Study of Current Discharge Behavior and Hard X-ray Anisotropy by APF Plasma Focus Device

    Science.gov (United States)

    Habibi, M.; Amrollahi, R.; Attaran, M.

    2009-03-01

    Amirkabir (APF) is a new Mather-type plasma focus device (16 kV, 36 μf, and 115 nH). In this work we present some experimental results as variation of discharge current signal respect to applied voltage at the optimum pressure, focusing time of plasma versus gas pressure, and variations of current discharge with different insulator sleeve dimensions. As we prospected optimum pressure tending to increase as we tried to higher voltage levels. The time taken by the current sheath to lift-off the insulator surface and therefore quality of pinched plasma depends on the length of the insulator sleeve. The results show that the insulator diameter can influence on pinch quality. Behavior of hard X-ray (HXR) signals with the pressure and also anisotropy of HXR investigated by the use of two scintillation detectors. The distribution of HXR intensity shows a large anisotropy with a maximum intensity between 22.5° and 45° and also between -22.5° and -67.5°.

  13. Bipolar and unipolar resistive switching behaviors of sol–gel-derived SrTiO3 thin films with different compliance currents

    International Nuclear Information System (INIS)

    Tang, M H; Wang, Z P; Zeng, Z Q; Xu, X L; Wang, G Y; Zhang, L B; Xiao, Y G; Yang, S B; Jiang, B; Li, J C; He, J

    2011-01-01

    The SrTiO 3 (STO) thin films on a Pt/Ti/SiO 2 /Si substrate were synthesized using a sol–gel method to form a metal–insulator–metal structure. This device shows the bipolar resistance switching (BRS) behavior for a compliance current I cc of less than 0.1 mA but exhibits soft breakdown at a higher level of compliance current. A transition from the BRS behavior to the stable unipolar resistive switching behavior (URS) was also observed. We found that the BRS behavior may be controlled by the structure interface while the URS behavior is likely bulk controlled. Our study indicates that the external compliance current is a key factor in resistance switching phenomenon of STO thin films

  14. Managing severe behavioral symptoms of a patient with anti-NMDAR encephalitis: case report and findings in current literature

    Directory of Open Access Journals (Sweden)

    Vanina Lima Monteiro

    2015-03-01

    Full Text Available Objective: Psychiatric symptoms emerge in the early stages of anti-N-methyl-D-aspartate receptor (anti-NMDAR encephalitis, and patients often seek treatment in psychiatric departments before visiting any other general medical services. Numerous articles about anti-NMDAR encephalitis have been published in the scientific community worldwide, but few emphasize the role of psychiatry in symptom management.Case description: We describe the case of a patient with anti- -NMDAR encephalitis seen in our service and discuss the management of behavioral symptoms based on current scientific literature. High doses of atypical antipsychotics and benzodiazepines were used to control agitation, and trazodone was administered to treat insomnia.Comments: Consultation-liaison psychiatry may help the healthcare team adjust the management of neuropsychiatric complications that might affect inpatients with anti-NMDAR encephalitis.

  15. Corrosion Behavior of X80 Steel with Coupled Coating Defects under Alternating Current Interference in Alkaline Environment.

    Science.gov (United States)

    Li, Zhong; Li, Caiyu; Qian, Hongchang; Li, Jun; Huang, Liang; Du, Cuiwei

    2017-06-28

    The corrosion behavior of X80 steel in the presence of coupled coating defects was simulated and studied under the interference of alternating current (AC) in an alkaline environment. The results from electrochemical measurements showed that the electrode potential of the coating defect with the smaller exposed area was lower than that with the larger area, which indicated that the steel with the smaller coating defect was more prone to corrosion. The result of weight loss tests also showed that the smaller coating defect had induced a higher corrosion rate. However, the corrosion rate of X80 steel at the larger coating defect decreased gradually with the increase of the larger defect area at a constant smaller defect area. The corrosion morphology images showed that the coating defects with smaller areas suffered from more severe pitting corrosion.

  16. Modulation of Jupiter's plasma flow, polar currents, and auroral precipitation by solar wind-induced compressions and expansions of the magnetosphere: a simple theoretical model

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2007-06-01

    Full Text Available We construct a simple model of the plasma flow, magnetosphere-ionosphere coupling currents, and auroral precipitation in Jupiter's magnetosphere, and examine how they respond to compressions and expansions of the system induced by changes in solar wind dynamic pressure. The main simplifying assumption is axi-symmetry, the system being modelled principally to reflect dayside conditions. The model thus describes three magnetospheric regions, namely the middle and outer magnetosphere on closed magnetic field lines bounded by the magnetopause, together with a region of open field lines mapping to the tail. The calculations assume that the system is initially in a state of steady diffusive outflow of iogenic plasma with a particular equatorial magnetopause radius, and that the magnetopause then moves rapidly in or out due to a change in the solar wind dynamic pressure. If the change is sufficiently rapid (~2–3 h or less the plasma angular momentum is conserved during the excursion, allowing the modified plasma angular velocity to be calculated from the radial displacement of the field lines, together with the modified magnetosphere-ionosphere coupling currents and auroral precipitation. The properties of these transient states are compared with those of the steady states to which they revert over intervals of ~1–2 days. Results are shown for rapid compressions of the system from an initially expanded state typical of a solar wind rarefaction region, illustrating the reduction in total precipitating electron power that occurs for modest compressions, followed by partial recovery in the emergent steady state. For major compressions, however, typical of the onset of a solar wind compression region, a brightened transient state occurs in which super-rotation is induced on closed field lines, resulting in a reversal in sense of the usual magnetosphere-ionosphere coupling current system. Current system reversal results in accelerated auroral electron

  17. Transcranial alternating current stimulation (tACS increases risk taking behavior in the Balloon Analogue Risk Task

    Directory of Open Access Journals (Sweden)

    Tal eSela

    2012-02-01

    Full Text Available The process of evaluating risks and benefits involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC. It has been proposed that in conflict and reward situations, theta-band (4–8 Hz oscillatory activity in the frontal cortex may reflect an electrophysiological mechanism for coordinating neural networks monitoring behavior, as well as facilitating task-specific adaptive changes. The goal of the present study was to investigate the hypothesis that theta-band oscillatory balance between right and left frontal and prefrontal regions, with a predominance role to the right hemisphere, is crucial for regulatory control during decision-making under risk. In order to explore this hypothesis, we used transcranial Alternating Current Stimulation (tACS, a novel technique that provides the opportunity to explore the functional role of neuronal oscillatory activities and to establish a causal link between specific oscillations and functional lateralization in risky decision-making situations. For this aim, healthy participants were randomly allocated to one of three stimulation groups (LH stimulation / RH stimulation / Sham stimulation, with active AC stimulation delivered in a frequency-dependent manner (at 6.5 Hz; 1mA peak to-peak. During the AC stimulation, participants performed the Balloon Analog Risk Task. This experiment revealed that participants receiving LH stimulation displayed riskier decision-making style compared to sham and RH stimulation groups. However, there was no difference in decision-making behaviors between sham and RH stimulation groups. The current study extends the notion that DLPFC activity is critical for adaptive decision-making in the context of risk-taking and emphasis the role of theta-band oscillatory activity during risky decision-making situations.

  18. Polarization-Dependent Multi-Functional Metamaterial as Polarization Filter, Transparent Wall and Circular Polarizer using Ring-Cross Resonator

    Directory of Open Access Journals (Sweden)

    Z. Zhang

    2017-09-01

    Full Text Available We propose a polarization-dependent multi-functional metamaterial using ring-cross resonator. Based on the analysis of surface current distributions induced by different polarized incidence, we demonstrate that the proposed metamaterial serves as a polarization filter, a transparent wall and a circular polarizer under different polarization normal incidence. Additionally, parameter analyses on the control of resonance are discussed to complementally explain the physical origin. Simulated results show that the proposed metamaterial functions as a polarization filter eliminating the x-polarization wave at 10.1 GHz and y-polarization wave at 14.3 GHz, a transparent wall transmitting both x-polarized and y-polarized incident waves at 12.6 GHz, and a broadband circular polarizer converting the +45° polarized (-45° polarized incident wave to the left (right handed circularly polarized wave from 10.8 to 12.8 GHz, respectively. Measured results agree well with the simulation and validate the performance of the proposed multifunctional metamaterial.

  19. Current Knowledge and Future Research on Infant Feeding in the Context of HIV: Basic, Clinical, Behavioral, and Programmatic Perspectives12

    Science.gov (United States)

    Young, Sera L.; Mbuya, Mduduzi N. N.; Chantry, Caroline J.; Geubbels, Eveline P.; Israel-Ballard, Kiersten; Cohan, Deborah; Vosti, Stephen A.; Latham, Michael C.

    2011-01-01

    In 2008, between 129,000 and 194,000 of the 430,000 pediatric HIV infections worldwide were attributable to breastfeeding. Yet in many settings, the health, economic, and social consequences of not breastfeeding would have dire consequences for many more children. In the first part of this review we provide an overview of current knowledge about infant feeding in the context of HIV. Namely, we describe the benefits and risks of breastmilk, the evolution of recommended infant feeding modalities in high-income and low-income countries in the last two decades, and contextualize the recently revised guidelines for infant feeding in the context of HIV current knowledge. In the second section, we suggest areas for future research on the postnatal prevention of mother-to-child transmission of HIV (PMTCT) in developing and industrialized countries. We suggest two shifts in perspective. The first is to evaluate PMTCT interventions more holistically, to include the psychosocial and economic consequences as well as the biomedical ones. The second shift in perspective should be one that contextualizes postnatal PMTCT efforts in the cascade of maternal health services. We conclude by discussing basic, clinical, behavioral, and programmatic research questions pertaining to a number of PMTCT efforts, including extended postnatal ARV prophylaxis, exclusive breastfeeding promotion, counseling, breast milk pasteurization, breast milk banking, novel techniques for making breast milk safer, and optimal breastfeeding practices. We believe the research efforts outlined here will maximize the number of healthy, thriving, HIV-free children around the world. PMID:22332055

  20. Precision measurement of the cross section of charged-current and neutral current processes at large Q{sup 2} at HERA with the polarized-electron beam; Mesures de precision de la section efficace des processus courant charge et courant neutre a grand Q{sup 2} a HERA avec le faisceau d'electrons polarises

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Trong Hieu

    2011-04-15

    The inclusive cross sections for both charged and neutral current processes have been measured in interactions of longitudinally polarized electrons (positrons) with unpolarized protons using the full data samples collected by H1 at HERA-II. The data taken at a center-of-mass energy of 319 GeV correspond to an integrated luminosity of 149.1 pb{sup -1} and 180.0 pb{sup -1} for e{sup -}p and e{sup +}p collisions, representing an increase in statistics of a factor of 10 and 2, respectively, over the data from HERA-I. The measured double differential cross sections d{sup 2}{sigma}/dxdQ{sup 2} cover more than two orders of magnitude in both Q{sup 2}, the negative four-momentum transfer squared, up to 30000 GeV{sup 2}, and Bjorken x, down to 0.003. The cross section data are compared to predictions of the Standard Model which is able to provide a good description of the data. The polarization asymmetry as a function of Q{sup 2} is measured with improved precision, confirming the previous observation of P violation effect in neutral current ep scattering at distances down to 10{sup -18} m. The total cross sections of the charged current process, for Q{sup 2} > 400 GeV{sup 2} and inelasticity y < 0.9 are measured for 4 independent data samples with e{sup {+-}} beams and different polarization values. Together with the corresponding cross section obtained from the previously published unpolarized data, the polarization dependence of the charged current cross section is measured and found to be in agreement with the Standard Model prediction with the absence of right-handed charged current. The cross sections are combined with previously published data from H1 to obtain the most precise unpolarized measurements. These are used to extract the structure function xF{sub 3}{sup {gamma}}{sup Z} which is sensitive to the valence quark distributions down to low x values. The new cross sections have also been used in a combined electroweak and QCD fit to significantly improve the

  1. Polarized advanced fuel reactors

    International Nuclear Information System (INIS)

    Kulsrud, R.M.

    1987-07-01

    The d- 3 He reaction has the same spin dependence as the d-t reaction. It produces no neutrons, so that if the d-d reactivity could be reduced, it would lead to a neutron-lean reactor. The current understanding of the possible suppression of the d-d reactivity by spin polarization is discussed. The question as to whether a suppression is possible is still unresolved. Other advanced fuel reactions are briefly discussed. 11 refs

  2. On polarization in biomembranes

    DEFF Research Database (Denmark)

    Zecchi, Karis Amata

    close to physiological conditions, making these effects biologically relevant. In this work, we consider the case of asymmetric membranes which can display spontaneous polarization in the absence of a field. Close to the phase transition, we find that the membrane displays piezoelectric, flexoelectric...... on different geometries point in the direction of a flexoelectric mechanism behind current rectification in lipid bilayers. Finally, we suggest that our updated equivalent circuit should be included in the interpretation of elctrophysiological data....

  3. An evaluation of the environmental fate and behavior of munitions materiel (tetryl and polar metabolites of TNT) in soil and plant systems

    International Nuclear Information System (INIS)

    Fellows, R.J.; Harvey, S.D.; Cataldo, D.A.

    1993-09-01

    A preliminary study was conducted to elucidate the nature of the polar metabolites reported for plant tissues and xylem exudates following root accumulation of trinitrotoluene. Studies focused on the nature of the proposed conjugates of TNT-residues in xylem exudates of bush beam plants. Use of enzymatic methods failed to demonstrate that the conjugates were carbohydrate based, but acid hydrolysis indicated that the conjugates may be protein based. Of the five polar conjugates isolated from exudates, the presence of aminodinitrotoluene isomers and one unknown TNT residue was demonstrated

  4. Multi-step resistive switching behavior of Li-doped ZnO resistance random access memory device controlled by compliance current

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Cheng [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Mathematic and Physical Sciences, R.O.C. Air Force Academy, Kaohsiung 820, Taiwan (China); Tang, Jian-Fu; Su, Hsiu-Hsien [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Hong, Cheng-Shong; Huang, Chih-Yu [Department of Electronic Engineering, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China)

    2016-06-28

    The multi-step resistive switching (RS) behavior of a unipolar Pt/Li{sub 0.06}Zn{sub 0.94}O/Pt resistive random access memory (RRAM) device is investigated. It is found that the RRAM device exhibits normal, 2-, 3-, and 4-step RESET behaviors under different compliance currents. The transport mechanism within the device is investigated by means of current-voltage curves, in-situ transmission electron microscopy, and electrochemical impedance spectroscopy. It is shown that the ion transport mechanism is dominated by Ohmic behavior under low electric fields and the Poole-Frenkel emission effect (normal RS behavior) or Li{sup +} ion diffusion (2-, 3-, and 4-step RESET behaviors) under high electric fields.

  5. Multi-step resistive switching behavior of Li-doped ZnO resistance random access memory device controlled by compliance current

    International Nuclear Information System (INIS)

    Lin, Chun-Cheng; Tang, Jian-Fu; Su, Hsiu-Hsien; Hong, Cheng-Shong; Huang, Chih-Yu; Chu, Sheng-Yuan

    2016-01-01

    The multi-step resistive switching (RS) behavior of a unipolar Pt/Li 0.06 Zn 0.94 O/Pt resistive random access memory (RRAM) device is investigated. It is found that the RRAM device exhibits normal, 2-, 3-, and 4-step RESET behaviors under different compliance currents. The transport mechanism within the device is investigated by means of current-voltage curves, in-situ transmission electron microscopy, and electrochemical impedance spectroscopy. It is shown that the ion transport mechanism is dominated by Ohmic behavior under low electric fields and the Poole-Frenkel emission effect (normal RS behavior) or Li + ion diffusion (2-, 3-, and 4-step RESET behaviors) under high electric fields.

  6. Titan Polar Landscape Evolution

    Science.gov (United States)

    Moore, Jeffrey M.

    2016-01-01

    With the ongoing Cassini-era observations and studies of Titan it is clear that the intensity and distribution of surface processes (particularly fluvial erosion by methane and Aeolian transport) has changed through time. Currently however, alternate hypotheses substantially differ among specific scenarios with respect to the effects of atmospheric evolution, seasonal changes, and endogenic processes. We have studied the evolution of Titan's polar region through a combination of analysis of imaging, elevation data, and geomorphic mapping, spatially explicit simulations of landform evolution, and quantitative comparison of the simulated landscapes with corresponding Titan morphology. We have quantitatively evaluated alternate scenarios for the landform evolution of Titan's polar terrain. The investigations have been guided by recent geomorphic mapping and topographic characterization of the polar regions that are used to frame hypotheses of process interactions, which have been evaluated using simulation modeling. Topographic information about Titan's polar region is be based on SAR-Topography and altimetry archived on PDS, SAR-based stereo radar-grammetry, radar-sounding lake depth measurements, and superposition relationships between geomorphologic map units, which we will use to create a generalized topographic map.

  7. Strategic Polarization.

    Science.gov (United States)

    Kalai, Adam; Kalai, Ehud

    2001-08-01

    In joint decision making, similarly minded people may take opposite positions. Consider the example of a marriage in which one spouse gives generously to charity while the other donates nothing. Such "polarization" may misrepresent what is, in actuality, a small discrepancy in preferences. It may be that the donating spouse would like to see 10% of their combined income go to charity each year, while the apparently frugal spouse would like to see 8% donated. A simple game-theoretic analysis suggests that the spouses will end up donating 10% and 0%, respectively. By generalizing this argument to a larger class of games, we provide strategic justification for polarization in many situations such as debates, shared living accommodations, and disciplining children. In some of these examples, an arbitrarily small disagreement in preferences leads to an arbitrarily large loss in utility for all participants. Such small disagreements may also destabilize what, from game-theoretic point of view, is a very stable equilibrium. Copyright 2001 Academic Press.

  8. Anodic Concentration Polarization in SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Williford, Rick E.; Chick, Lawrence A.; Maupin, Gary D.; Simner, Steve P.; Stevenson, Jeffry W.; Khaleel, Mohammad A.; Wachsman, ED, et al

    2003-08-01

    Concentration polarization is important because it determines the maximum power output of a solid oxide fuel cell (SOFC) at high fuel utilization. Anodic concentration polarization occurs when the demand for reactants exceeds the capacity of the porous ceramic anode to supply them by gas diffusion mechanisms. High tortuosities (bulk diffusion resistances) are often assumed to explain this behavior. However, recent experiments show that anodic concentration polarization originates in the immediate vicinity of the reactive triple phase boundary (TPB) sites near the anode/electrolyte interface. A model is proposed to describe how concentration polarization is controlled by two localized phenomena: competitive adsorption of reactants in areas adjacent to the reactive TPB sites, followed by relatively slow surface diffusion to the reactive sites. Results suggest that future SOFC design improvements should focus on optimization of the reactive area, adsorption, and surface diffusion at the anode/electrolyte interface.

  9. Transcranial direct current stimulation reduces food-craving and measures of hyperphagia behavior in participants with Prader-Willi syndrome.

    Science.gov (United States)

    Bravo, Gabriela L; Poje, Albert B; Perissinotti, Iago; Marcondes, Bianca F; Villamar, Mauricio F; Manzardo, Ann M; Luque, Laura; LePage, Jean F; Stafford, Diane; Fregni, Felipe; Butler, Merlin G

    2016-03-01

    Prader-Willi syndrome (PWS) is a neurodevelopmental genetic disorder characterized by intellectual disabilities and insatiable appetite with compulsive eating leading to severe obesity with detrimental health consequences. Transcranial direct current stimulation (tDCS) has been shown to modulate decision-making and cue-induced food craving in healthy adults. We conducted a pilot double blind, sham-controlled, multicenter study of tDCS modulation of food drive and craving in 10 adult PWS participants, 11 adult obese (OB) and 11 adult healthy-weight control (HWC) subjects. PWS and OB subjects received five consecutive daily sessions of active or sham tDCS over the right dorsolateral prefrontal cortex (DLPFC), while HWC received a single sham and active tDCS in a crossover design. Standardized psychometric instruments assessed food craving, drive and hyperphagia by self-report and caregiver assessment over 30 days. Robust baseline differences were observed in severity scores for the Three-Factor Eating Questionnaire (TFEQ) and Dykens Hyperphagia Questionnaire (DHQ) for PWS compared to HWC while obese participants were more similar to HWC. Active tDCS stimulation in PWS was associated with a significant change from baseline in TFEQ Disinhibition (Factor II) (Ƶ = 1.9, P < 0.05, 30 days) and Total Scores (Ƶ = 2.3, P < 0.02, 30 days), and participant ratings of the DHQ Severity (Ƶ = 1.8, P < 0.06, 5 days) and Total Scores (Ƶ = 1.9, P < 0.05, 15 days). These findings support sustained neuromodulatory effects and efficacy of tDCS to reduce food drive and behaviors impacting hyperphagia in PWS. Transcranial direct current stimulation may represent a straight-forward, low risk and low cost method to improve care, management and quality of life in PWS. © 2015 Wiley Periodicals, Inc.

  10. Climate Change, Polar Bears and their management

    OpenAIRE

    Derenchenko, Liza

    2010-01-01

    This is a literature study of polar bears in the context of climate change: what kind of creatures are polar bears, what are the main interpretations of current climate change, how might the polar bear adapt to these changes (feeding strategies) and how are the bears being managed (hunting)? These are relevant questions , since climate change is on the agenda, and polar bears being the apex predators of the Arctic are a key representation of the wildlife there. The third element of polar bear...

  11. Inclusive quasielastic scattering of polarized electrons from polarized nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Amaro, J.E. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Center for Theoretical Physics]|[Universidad de Granada (Spain). Dept. de Fisica Moderna]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Lab. for Nuclear Science]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Caballero, J.A. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia]|[Sevilla Univ. (Spain). Dept. de Fisica Atomica, Molecular y Nuclear; Donnelly, T.W. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Center for Theoretical Physics]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Lab. for Nuclear Science]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Moya de Guerra, E. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia

    1996-12-23

    The inclusive quasielastic response functions that appear in the scattering of polarized electrons from polarized nuclei are computed and analyzed for several closed-shell-minus-one nuclei with special attention paid to {sup 39}K. Results are presented using two models for the ejected nucleon - when described by a distorted wave in the continuum shell model or by a plane wave in PWIA with on- and off-shell nucleons. Relativistic effects in kinematics and in the electromagnetic current have been incorporated throughout. Specifically, the recently obtained expansion of the electromagnetic current in powers only of the struck nucleon`s momentum is employed for the on-shell current and the effects of the first-order terms (spin-orbit and convection) are compared with the zeroth-order (charge and magnetization) contributions. The use of polarized inclusive quasielastic electron scattering as a tool for determining near-valence nucleon momentum distributions is discussed. (orig.).

  12. Analyzing the propagation behavior of coherence and polarization degrees of a phase-locked partially coherent radial flat-topped array laser beam in underwater turbulence.

    Science.gov (United States)

    Kashani, Fatemeh Dabbagh; Yousefi, Masoud

    2016-08-10

    In this research, based on an analytical expression for cross-spectral density (CSD) matrix elements, coherence and polarization properties of phase-locked partially coherent flat-topped (PCFT) radial array laser beams propagating through weak oceanic turbulence are analyzed. Spectral degrees of coherence and polarization are analytically calculated using CSD matrix elements. Also, the effective width of spatial degree of coherence (EWSDC) is calculated numerically. The simulation is done by considering the effects of source parameters (such as radius of the array setup's circle, effective width of the spectral degree of coherence, and wavelength) and turbulent ocean factors (such as the rate of dissipation of the turbulent kinetic energy per unit mass of fluid and relative strength of temperature and salinity fluctuations, Kolmogorov micro-scale, and rate of dissipation of the mean squared temperature) in detail. Results indicate that any change in the amount of turbulence factors that increase the turbulence power reduces the EWSDC significantly and causes the reduction in the degree of polarization, and occurs at shorter propagation distances but with smaller magnitudes. In addition, being valid for all conditions, the degradation rate of the EWSDC of Gaussian array beams are more in comparison with the PCFT ones. The simulation and calculation results are shown by graphs.

  13. Precessing deuteron polarization

    International Nuclear Information System (INIS)

    Sitnik, I.M.; Volkov, V.I.; Kirillov, D.A.; Piskunov, N.M.; Plis, Yu.A.

    2002-01-01

    The feasibility of the acceleration in the Nuclotron of deuterons polarized in the horizontal plane is considered. This horizontal polarization is named precessing polarization. The effects of the main magnetic field and synchrotron oscillations are included. The precessing polarization is supposed to be used in studying the polarization parameters of the elastic dp back-scattering and other experiments

  14. Repeated Transcranial Direct Current Stimulation Induces Behavioral, Metabolic and Neurochemical Effects in Rats on High-Calorie Diet

    Directory of Open Access Journals (Sweden)

    Agata Ziomber

    2018-01-01

    Full Text Available Due to its high prevalence, obesity is considered an epidemic, which stimulated research on non-invasive methods to reduce excess body fat. Transcranial direct current stimulation (tDCS is a non-invasive technique used to modulate the activity of cerebral cortex, which has already found increasing interest in medicine as a promising methodology. The aim of this study was to analyze the impact of tDCS on feeding behavior, metabolic abnormalities and neurotransmitters in certain brain areas involved in appetite control of obese rats. The male Wistar rats were divided into five subgroups depending on consumed diet effect (lean, obese and tDCS type (anodal, cathodal, sham, and no stimulation. Two 10-min daily sessions of tDCS for 8 consecutive days of the study were applied. Rats subjected to active tDCS (anodal right or cathodal left of the prefrontal cortex had reduced appetite and showed lesser body weight gain than the animals subjected to sham procedure or those receiving no stimulation at all. Furthermore, tDCS contributed to reduction of epididymal fat pads and to a decrease in blood concentration of leptin. Neurochemical examination revealed that tDCS modulated serotonin pathways of the reward-related brain areas and contributed to a significant decrease in the density of D2 but not D1 dopamine receptors in the dorsal striatum, recorded 5 h after the last stimulation. No significant effect of tDCS on dopamine and it's metabolites in examined brain regions was observed. It seems that the hypothalamus was not affected by tDCS application as no changes in measured neurotransmitters were detected at any examined time point. However, these results do not exclude the possibility of the delayed response of the monoamines in the examined brain areas to tDCS application. Altogether, these findings imply that repeated tDCS of the prefrontal cortex may change feeding behavior of obese rats. Either right anodal or left cathodal tDCS were sufficient to

  15. Spin-polarized current in noncollinear antiferromagnets

    Czech Academy of Sciences Publication Activity Database

    Železný, Jakub; Zhang, Y.; Felser, C.; Yan, B.

    2017-01-01

    Roč. 119, č. 18 (2017), s. 1-7, č. článku 187204. ISSN 0031-9007 Institutional support: RVO:68378271 Keywords : anisotropic magnetoresistance * wannier functions * room-temperature * torques * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 8.462, year: 2016

  16. Polare maskuliniteter

    Directory of Open Access Journals (Sweden)

    Marit Anne Hauan

    2012-05-01

    Full Text Available In this paper my aim is to read and understand the journal of Gerrit de Veer from the last journey of William Barents to the Arctic Regions in 1596 and the journal of captain Junge on his hunting trip from Tromsø to Svalbard in 1834.It is nearly 240 years between this to voyages. The first journal is known as the earliest report from the arctic era. Gerrit de Veer adds instructive copper engravings to his text and give us insight in the crews meeting with this new land. Captain Junges journal is found together with his dead crew in a house in a fjord nearby Ny-Ålesund and has no drawings, but word. Both of these journals may be read as sources of the knowledge and understanding of the polar region. They might also unveil the ideas of how to deal with and survive under the challenges that is given. In addition one can ask if the sources can tell us more about how men describe their challenges. Can the way they expressed themselves in the journals give us an understanding of masculinity? And not least help us to create good questions of the change in the ideas of masculinities which is said to follow the change in understanding of the wilderness.

  17. Behaviorism

    Science.gov (United States)

    Moore, J.

    2011-01-01

    Early forms of psychology assumed that mental life was the appropriate subject matter for psychology, and introspection was an appropriate method to engage that subject matter. In 1913, John B. Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the…

  18. Behavior

    NARCIS (Netherlands)

    Bouwman, L.I.

    2014-01-01

    Health behaviors are people’s actions, some purposefully deployed to promote or protect health; some thoughtlessly undertaken without concern for their potential risk to health; some consciously, even defiantly, deployed regardless of consequences to health. Risk behaviors are specific forms of

  19. Geomagnetic polarity transitions

    Science.gov (United States)

    Merrill, Ronald T.; McFadden, Phillip L.

    1999-05-01

    reasonable to draw the following conclusions with varying degrees of confidence. There appears to be a substantial decrease in the mean intensity of the dipole field during a transition to ˜25% of its usual value. The duration of an average geomagnetic polarity transition is not well known but probably lies between 1000 and 8000 years. Values outside these bounds have been reported, but we give reasons as to why such outliers are likely to be artifacts. The reversal process is probably longer than the manifestation of the reversal at Earth's surface as recorded in paleomagnetic directional data. Convection hiatus during a geomagnetic polarity transition seems unlikely, and free-decay models for reversals appear to be generally incompatible with the data. This implies that certain theorems in dynamo theory, such as Cowling's theorem, should not be invoked to explain the origin of reversals. Unfortunately, the detailed description of directional changes during transitions remains controversial. Contrary to common belief, certain low-degree nondipole fields can produce significant longitudinal confinement of virtual geomagnetic poles (VGP) during a transition. The data are currently inadequate to refute or verify claims of longitudinal dipole confinement, VGP clustering, or other systematics during polarity transitions.

  20. Consideration of Culture and Context in School-Wide Positive Behavior Support: A Review of Current Literature

    Science.gov (United States)

    Fallon, Lindsay M.; O'Keeffe, Breda V.; Sugai, George

    2012-01-01

    A review of the literature related to culture and student behavior reveals a number of interesting observations that are not surprising. First, culture is a difficult construct to define and has been defined variably over the years. Second, schools are becoming increasingly diverse, and evidence-based behavior management practices have been…

  1. Advancements on Radar Polarization Information Acquisition and Processing

    Directory of Open Access Journals (Sweden)

    Dai Dahai

    2016-04-01

    Full Text Available The study on radar polarization information acquisition and processing has currently been one important part of radar techniques. The development of the polarization theory is simply reviewed firstly. Subsequently, some key techniques which include polarization measurement, polarization anti-jamming, polarization recognition, imaging and parameters inversion using radar polarimetry are emphatically analyzed in this paper. The basic theories, the present states and the development trends of these key techniques are presented and some meaningful conclusions are derived.

  2. DMSP SSM/I Daily and Monthly Polar Gridded Bootstrap Sea Ice Concentrations

    Data.gov (United States)

    National Aeronautics and Space Administration — DMSP SSM/I Daily and Monthly Polar Gridded Bootstrap Sea Ice Concentrations in polar stereographic projection currently include Defense Meteorological Satellite...

  3. Smoking behaviors and intentions among current e-cigarette users, cigarette smokers, and dual users: A national survey of U.S. high school seniors.

    Science.gov (United States)

    McCabe, Sean Esteban; Veliz, Phil; McCabe, Vita V; Boyd, Carol J

    2017-06-01

    E-cigarette use among adolescents has increased significantly in recent years, but it remains unclear whether cigarette smoking behaviors and intentions for future cigarette smoking differ among current (i.e., 30-day) non-users, only e-cigarette users, only cigarette smokers, and dual users. A nationally representative sample of 4385 U.S. high school seniors were surveyed during the spring of their senior year via self-administered questionnaires in 2014. An estimated 9.6% of U.S. high school seniors reported current e-cigarette use only, 6.3% reported current cigarette smoking only, and 7.2% reported current dual use of e-cigarettes and cigarette smoking. There were no significant differences between current only cigarette smokers and dual users in the odds of early onset of cigarette smoking, daily cigarette smoking, intentions for future cigarette smoking, friends' cigarette smoking behaviors, attempts to quit cigarette smoking, or the inability to quit cigarette smoking. Adolescents who only used e-cigarettes had higher odds of intentions for future cigarette smoking in the next 5years (AOR=2.57, 95% CI: 1.21-5.24) than current non-users. Dual users and only cigarette smokers had higher odds of cigarette smoking behaviors and intentions for future cigarette smoking than non-users or only e-cigarette users. Adolescents who engage in current dual use have cigarette smoking behaviors and intentions for future cigarette smoking that more closely resemble cigarette smokers than e-cigarette users. Adolescents who only use e-cigarettes have higher intentions to engage in future cigarette smoking relative to their peers who do not engage in e-cigarette use or cigarette smoking. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Primordial Inflation Polarization Explorer: Status and Plans

    Science.gov (United States)

    Kogut, Alan

    2009-01-01

    The Primordial Inflation Polarization Explorer is a balloon-borne instrument to measure the polarization of the cosmic microwave background in order to detect the characteristic signature of gravity waves created during an inflationary epoch in the early universe. PIPER combines cold /I.G K\\ optics, 5120 bolometric detectors, and rapid polarization modulation using VPM grids to achieve both high sensitivity and excellent control of systematic errors. I will discuss the current status and plans for the PIPER instrument.

  5. Frequency-Dependent Solvent Impedance and Colloid Microelectrophoresis Measurements in Partially Polar Solvents.

    Science.gov (United States)

    Hayden, Edward; Aljabal, Zena; Yethiraj, Anand

    2017-05-16

    We carry out frequency-dependent solvent impedance measurements and alternating current (ac) colloid microelectrophoresis experiments in partially polar solvents in the low-frequency regime (0.25 Hz ≤ f ≤ 10 Hz). Solvent electrode polarization effects are quantified first in partially polar solvent mixtures containing bromocyclohexane (CHB). We find that the polarization capacitance from electrode polarization exhibits a clear power law behavior C p = C p0 f -m with power law exponent m = 0.25 ± 0.04. Once we account for electrode polarization effects, we are able to obtain quantitative mobilities in the low-frequency regime from our ac microelectrophoresis measurements; for these measurements, we use poly(methyl methacrylate colloids that are gravitationally confined to a plane while suspended in a low-polar solvent mixture of cis-trans decahydronapthalene and CHB. We find that the dimensionless electrophoretic mobility is constant, consistent with expectations for frequencies below the ion-diffusion frequency, and has a value E = 1.6 ± 0.4.

  6. Influences of poly[(styrene)x-stat-(chloromethylstyrene)y]s additives on dewetting behaviors of polystyrene thin films: effects of polar group ratio and film thickness

    International Nuclear Information System (INIS)

    Sangjan, Suntree; Traiphol, Nisanart; Traiphol, Rakchart

    2012-01-01

    This contribution investigates the addition of poly(styrene-stat-chloromethylstyrene (ClMS))s as dewetting inhibitors of polystyrene (PS) thin films with thicknesses ranging from 12 to 38 nm. The ClMS ratios in the copolymers are 5, 25 and 45 mol%. Atomic force microscopy and optical microscopy are utilized to follow morphological changes of blended PS/copolymer films upon annealing above their glass transition temperatures. We have found that thermal stability of the PS films is greatly improved when a small amount of the copolymers is added into the system. The polar ClMS groups provide anchoring sites with the polar SiO x /Si substrate while the styrene segments favorably interact with the PS matrix. The effectiveness of the copolymers as dewetting inhibitors is also found to increase with mole ratio of ClMS group. While the stability of PS films is systematically improved upon addition of the highly substituted copolymers, using the copolymer with relatively low ratio of ClMS group could lead to the opposite result. This class of copolymers can be utilized for improving thermal stability of ultrathin PS films. The fundamental knowledge from this study is also important for designing or selecting structure of additives used to improve the stability of polymeric thin films. - Highlights: ► Efficient method for improving stability of polystyrene (PS) thin films. ► Poly(styrene-stat-chloromethylstyrene)s are used as dewetting inhibitors. ► Thermal stability of blended PS/copolymers greatly improved. ► Effectiveness of the copolymers increases with mole ratio of chloromethylstyrene group. ► Important results for designing materials in coating application.

  7. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  8. Effect of Nitrite Inhibitor on the Macrocell Corrosion Behavior of Reinforcing Steel

    Directory of Open Access Journals (Sweden)

    Zhonglu Cao

    2015-01-01

    Full Text Available The effect of nitrite ions on the macrocell corrosion behavior of reinforcing steel embedded in cement mortar was investigated by comparing and analyzing the macrocell corrosion current, macrocell polarization ratios, and slopes of anodic and cathodic steels. Based on the experimental results, the relationship between macrocell potential difference and macrocell current density was analyzed, and the mechanism of macrocell corrosion affected by nitrite ions was proposed. The results indicated that nitrite ions had significant impact on the macrocell polarization ratios of cathode and anode. The presence of nitrite could reduce the macrocell current by decreasing the macrocell potential difference and increasing the macrocell polarization resistance of the anode.

  9. Hyperon polarization: theory and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Magnin, J.; Simao, F.R.A.

    1996-01-01

    We give a brief review of the experimental situation concerning hyperon polarization. We mention also the current models developed to understand the experimental results and make some comments on some theoretical aspects contained in the Thomas precession model. (author). 8 ref.

  10. The SLC polarized electron source

    International Nuclear Information System (INIS)

    Clendenin, J.E.

    1990-10-01

    A polarized electron source consisting of a 3-electrode photocathode gun and a flashlamp-pumped dye laser has been designed and built for the SLC and is currently undergoing commissioning. The source is described, and the operating configuration is discussed. The present status of the source and future plans are briefly indicated. 7 refs., 4 figs

  11. A study of lithium deuteride as a material for a polarized target

    CERN Document Server

    Bültmann, S; Day, D B; Fatemi, R D; Gardner, B; Harris, C M; Johnson, J R; Mccarthy, J S; McKee, P M; Meyer, Werner T; Penttilae, S I; Ponikvar, E; Rijllart, A; Rondon, Oscar A; Lorant, S S; Tobias, W A; Trentalange, S; Zhu, H; Zihlmann, B; Zimmermann, D

    1999-01-01

    Experiment E155 at the Stanford Linear Accelerator Center (SLAC) measured the spin-dependent structure of the proton and neutron, using for the first time sup 6 LiD as the polarized deuteron target material in a high-energy electron beam. This compound provides a significantly higher dilution factor than any other solid deuteron target material currently used in high-energy physics experiments. Results of the polarization behavior of the sup 6 LiD target material before and after exposure to the 50 GeV/c electron beam used in E155 are presented.

  12. Current status on behavioral and biological markers of PTSD: a search for clarity in a conflicting literature.

    Science.gov (United States)

    Zoladz, Phillip R; Diamond, David M

    2013-06-01

    Extensive research has identified stereotypic behavioral and biological abnormalities in post-traumatic stress disorder (PTSD), such as heightened autonomic activity, an exaggerated startle response, reduced basal cortisol levels and cognitive impairments. We have reviewed primary research in this area, noting that factors involved in the susceptibility and expression of PTSD symptoms are more complex and heterogeneous than is commonly stated, with extensive findings which are inconsistent with the stereotypic behavioral and biological profile of the PTSD patient. A thorough assessment of the literature indicates that interactions among myriad susceptibility factors, including social support, early life stress, sex, age, peri- and post-traumatic dissociation, cognitive appraisal of trauma, neuroendocrine abnormalities and gene polymorphisms, in conjunction with the inconsistent expression of the disorder across studies, confounds attempts to characterize PTSD as a monolithic disorder. Overall, our assessment of the literature addresses the great challenge in developing a behavioral and biomarker-based diagnosis of PTSD. Published by Elsevier Ltd.

  13. Electron Cyclotron Waves Polarization in the TJII Stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Cappa, A.; Martinez-Fernandez, J.; Wagner, D.

    2013-05-01

    This report describes the theoretical calculations related with the electron cyclotron (EC) waves polarization control in the TJII stellarator. Two main aspects will be distinguished: the determination of the vacuum polarization that the wave must exhibit if a given propagation mode in a cold plasma is desired and the calculation of the behavior of the grooved polarizers and other transmission systems used to launch the vacuum wave with the required polarization. (Author) 13 refs.

  14. Associations of Trying to Lose Weight, Weight Control Behaviors, and Current Cigarette Use among US High School Students

    Science.gov (United States)

    Johnson, Jonetta L.; Eaton, Danice K.; Pederson, Linda L.; Lowry, Richard

    2009-01-01

    Background: Approximately one-quarter of high school students currently use cigarettes. Previous research has suggested some youth use smoking as a method for losing weight. The purpose of this study was to describe the association of current cigarette use with specific healthy and unhealthy weight control practices among 9th-12th grade students…

  15. Feasibility studies of a polarized positron source based on the Bremsstrahlung of polarized electrons

    International Nuclear Information System (INIS)

    Dumas, J.

    2011-09-01

    The nuclear and high-energy physics communities have shown a growing interest in the availability of high current, highly-polarized positron beams. A sufficiently energetic polarized photon or lepton incident on a target may generate, via Bremsstrahlung and pair creation within a solid target foil, electron-positron pairs that should carry some fraction of the initial polarization. Recent advances in high current (> 1 mA) spin polarized electron sources at Jefferson Lab offer the perspective of creating polarized positrons from a low energy electron beam. This thesis discusses polarization transfer from electrons to positrons in the perspective of the design optimization of a polarized positron source. The PEPPo experiment, aiming at a measurement of the positron polarization from a low energy (< 10 MeV) highly spin polarized electron beam is discussed. A successful demonstration of this technique would provide an alternative scheme for the production of low energy polarized positrons and useful information for the optimization of the design of polarized positron sources in the sub-GeV energy range. (author)

  16. Response to Intervention (RtI) in the Social, Emotional, and Behavioral Domains: Current Challenges and Emerging Possibilities

    Science.gov (United States)

    Saeki, Elina; Jimerson, Shane R.; Earhart, James; Hart, Shelley R.; Renshaw, Tyler; Singh, Renee D.; Stewart, Kaitlyn

    2011-01-01

    As many schools move toward a three-tier model that incorporates a Response to Intervention (RtI) service delivery model in the social, emotional, and behavioral domains, school psychologists may provide leadership. The decision-making process for filtering students through multiple tiers of support and intervention and examining change is an area…

  17. Polarized electroluminescence from silicon nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bagraev, Nikolay; Danilovsky, Eduard; Gets, Dmitry; Klyachkin, Leonid; Kudryavtsev, Andrey; Kuzmin, Roman; Malyarenko, Anna [Ioffe Physical-Technical Institute, 194021 St. Petersburg (Russian Federation); Mashkov, Vladimir [St. Petersburg State Polytechnical University, 195251 St. Petersburg (Russian Federation)

    2012-05-15

    We present the first findings of the circularly polarized electroluminescence (CPEL) from silicon nanostructures which are the p-type ultra-narrow silicon quantum well (Si-QW) confined by {delta}-barriers heavily doped with boron. The CPEL dependences on the forward current and lateral electric field show the circularly polarized light emission which appears to be caused by the exciton recombination through the negative-U dipole boron centers at the Si-QW-{delta}-barriers interface with the assistance of phosphorus donors. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Disruptive behavior in preschool children: distinguishing normal misbehavior from markers of current and later childhood conduct disorder.

    Science.gov (United States)

    Hong, Ji S; Tillman, Rebecca; Luby, Joan L

    2015-03-01

    To investigate which disruptive behaviors in preschool were normative and transient vs markers of conduct disorder, as well as which disruptive behaviors predicted the persistence of conduct disorder into school age. Data from a longitudinal study of preschool children were used to investigate disruptive behaviors. Caregivers of preschoolers ages 3.0-5.11 years (n = 273) were interviewed using the Preschool Age Psychiatric Assessment to derive the following diagnostic groups: conduct disorder, externalizing disorder without conduct disorder, internalizing disorder without externalizing disorder, and healthy. At school age, participants were again assessed via an age-appropriate diagnostic interview. Logistic and linear regression with pairwise group comparisons was used to investigate clinical markers of preschool conduct disorder and predictors of school age conduct disorder. Losing one's temper, low-intensity destruction of property, and low-intensity deceitfulness/stealing in the preschool period were found in both healthy and disordered groups. In contrast, high-intensity argument/defiant behavior, both low- and high-intensity aggression to people/animals, high-intensity destruction of property, high-intensity deceitfulness/stealing, and high-intensity peer problems were markers of preschool conduct disorder and predictors of school age conduct disorder. Inappropriate sexual behavior was not a marker for preschool conduct disorder but was a predictor of school age conduct disorder. These findings provide a guide for primary care clinicians to help identify preschoolers with clinical conduct disorder and those who are at risk for persistent conduct disorder in childhood. Preschoolers displaying these symptoms should be targeted for mental health assessment. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Polarization Observations of the Fermi blazars

    Science.gov (United States)

    Rani, Bindu; S. Jorstad, A. P. Marscher (BU, USA), K. Sokolovsky (IAASARS, Greece), I. Agudo (CSIC, Spain)

    2018-01-01

    Ever since the revolutionary discovery by the Fermi mission that active galactic nuclei (AGN) produce copious amounts of high-energy emission, its origin has remained elusive. Using high-frequency radio interferometry (VLBI) polarization imaging, we could probe the magnetic field topology of the compact high-energy emission regions in blazars. A case study for blazar 3C 279 reveals presence of multiple gamma-ray emission regions. The observed anti-correlation between gamma-ray flux and percentage polarization at optical bands challenges the current high-energy emission models. In addition to the turbulent component responsible for gamma-ray flares, our analysis suggests the presence of a steady polarized component having with its polarization direction aligned along the jet axis. The steady polarized component could possibly be the toroidal component of the helical magnetic field. To better understand the acceleration processes in jets, high-energy polarization missions are of great importance.

  20. Polar bears: the fate of an icon.

    Science.gov (United States)

    Fitzgerald, Kevin T

    2013-11-01

    Polar bears are one of the most iconic animals on our planet. Worldwide, even people who would never see one are drawn to these charismatic arctic ice hunters. They are the world's largest terrestrial carnivore, and despite being born on land, they spend most of their lives out on the sea ice and are considered a marine mammal. Current global studies estimate there are around 20,000 animals in some 19 discrete circumpolar populations. Aside from pregnant females denning in the winter months to give birth, the white bears do not hibernate. They spend their winters on the sea ice hunting seals, an activity they are spectacularly adapted for. Research on these animals is incredibly difficult because of the inhospitable surroundings they inhabit and how inaccessible they make the bears. For many years, the sum of our understanding of the natural history of polar bears came from tracks, scats, the remains of their kills, abandoned dens, and anecdotal observations of native hunters, explorers, and early biologists. Nonetheless, the last 40 years have seen a much better picture of their biology emerge thanks to, first, dedicated Canadian researchers and, later, truly international efforts of workers from many countries. Veterinarians have contributed to our knowledge of the bears by delivering and monitoring anesthesia, obtaining blood samples, performing necropsies, investigating their reproduction, conducting radiotelemetry studies, and examining their behavior. Recently, new technologies have been developed that revolutionize the study of the lives and natural history of undisturbed polar bears. These advances include better satellite radiotelemetry equipment and the development of remote-controlled miniature devices equipped with high-definition cameras. Such new modalities provide dramatic new insights into the life of polar bears. The remarkable degree of specialized adaptation to life on the sea ice that allowed the bears to be successful is the very reason that

  1. First time observation of local current shrinkage during the MARFE behavior on the J-TEXT tokamak

    Science.gov (United States)

    Shi, Peng; Zhuang, G.; Gentle, K.; Hu, Qiming; Chen, Jie; Li, Qiang; Liu, Yang; Gao, Li; Zhang, Xiaolong; Liu, Hai; Chen, Zhipeng; Zhu, Lizhi; Li, Fuming; Zhou, Yinan; Zeng, Zhong; Liu, Linzi; He, Jiyang

    2017-11-01

    Multifaceted asymmetric radiation as well as strong poloidal asymmetry of the electron density from the edge, dubbed as ‘MARFE’, has been observed in high electron density Ohmically heated plasmas on J-TEXT tokamak. Equilibrium reconstruction based on the measured data from the 17-channel FIR polarimeter-interferometer indicates that an asymmetric plasma current density distribution forms at the edge region and the plasma current shrinkage locates at the MARFE affected region. Furthermore, associated with the localized plasma current shrinkage, a locked mode MHD activity is excited, which then terminate the discharge with a major disruption. Localized plasma current shrinkage at the MARFE region is considered to be the direct cause for the density limit disruptions, and the proposed interpretation is consistent with the experimental observations.

  2. Geographical Income Polarization

    DEFF Research Database (Denmark)

    Azhar, Hussain; Jonassen, Anders Bruun

    inter municipal income inequality. Counter factual simulations show that rising property prices to a large part explain the rise in polarization. One side-effect of polarization is tendencies towards a parallel polarization of residence location patterns, where low skilled individuals tend to live......In this paper we estimate the degree, composition and development of geographical income polarization based on data at the individual and municipal level in Denmark from 1984 to 2002. Rising income polarization is reconfirmed when applying new polarization measures, the driving force being greater...

  3. PolarTrack: Optical Outside-In Device Tracking that Exploits Display Polarization

    DEFF Research Database (Denmark)

    Rädle, Roman; Jetter, Hans-Christian; Fischer, Jonathan

    2018-01-01

    PolarTrack is a novel camera-based approach to detecting and tracking mobile devices inside the capture volume. In PolarTrack, a polarization filter continuously rotates in front of an off-the-shelf color camera, which causes the displays of observed devices to periodically blink in the camera feed....... The periodic blinking results from the physical characteristics of current displays, which shine polarized light either through an LC overlay to produce images or through a polarizer to reduce light reflections on OLED displays. PolarTrack runs a simple detection algorithm on the camera feed to segment...... tracking accuracy and precision with similar tracking reliability. PolarTrack works as standalone multi-device tracking but is also compatible with existing camera-based tracking systems and can complement them to compensate for their limitations....

  4. Current Trends in Exercise Intervention Research, Technology, and Behavioral Change Strategies for People With Disabilities: A Scoping Review.

    Science.gov (United States)

    Lai, Byron; Young, Hui-Ju; Bickel, C Scott; Motl, Robert W; Rimmer, James H

    2017-10-01

    This review synthesized physical activity and exercise intervention literature for the past 10 yrs for people with physical and cognitive disabilities including intervention characteristics, behavior change strategies, and types of technologies used to improve targeted outcomes. Systematic searches yielded 132 eligible studies. The major disability groups were multiple sclerosis (41%), stroke (15%), and spinal cord injury (12%). Research designs primarily involved randomized controlled trials (61%) versus quasi-experimental designs (39%). Approximately 20% of the interventions used some form of the following technology: information and communication technology (48%), interactive technology (37%), or electronic gauges (30%). Eighteen percent of studies used intervention strategies based on behavioral theory, which was typically combined with technology to promote activity and increase adherence in generally larger study samples. The three prevailing theories included social cognitive theory (58%), supportive accountability theory (21%), and transtheoretical model (21%). Upon completing the intervention, studies reported primarily significant outcomes (80%). Exercise research for PWD has grown in both quantity and quality, but several gaps remain. Study findings provide a roadmap for future exercise trials on understudied populations and highlight technology and behavior change theory as drivers of future intervention research.

  5. Characteristics of output voltage and current of integrated nanogenerators

    KAUST Repository

    Yang, Rusen

    2009-01-01

    Owing to the anisotropic property and small output signals of the piezoelectric nanogenerators (NGs) and the influence of the measurement system and environment, identification of the true signal generated by the NG is critical. We have developed three criteria: Schottky behavior test, switching-polarity tests, and linear superposition of current and voltage tests. The 11 tests can effectively rule out the system artifacts, whose sign does not change with the switching measurement polarity, and random signals, which might change signs but cannot consistently add up or cancel out under designed connection configurations. This study establishes the standards for designing and scale up of integrated nanogenerators. © 2009 American Institute of Physics.

  6. PIPER: Primordial Inflation Polarization Explorer

    Science.gov (United States)

    Lazear, Justin; Benford, D.; Chuss, D.; Fixsen, D.; Hinderks, J.; Hinshaw, G.; Jhabvala, C.; Johnson, B.; Kogut, A.; Mirel, P.; Mosely, H.; Staguhn, J.; Wollack, E.; Weston, A.; Vlahacos, K.; Bennett, C.; Eimer, J.; Halpern, M.; Irwin, K.; Dotson, J.; Ade, P.; Tucker, C.

    2011-05-01

    The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne instrument to measure the polarization of the cosmic microwave background in search of the expected signature of primordial gravity waves excited during an inflationary epoch shortly after the Big Bang. PIPER consists of two co-aligned telescopes, one sensitive to the Q Stokes parameter and the other to U. Sky signals will be detected with 5120 transition edge sensor (TES) bolometers distributed in four rectangular close-packed arrays maintained at 100 mK. To maximize the sensitivity of the instrument, both telescopes are mounted within a single open bucket dewar and are maintained at 1.5 K throughout flight, with no ambient-temperature windows between the sky and the detectors. To mitigate the effects of systematic errors, the polarized sky signals will be modulated using a variable-delay polarization modulator. PIPER will observe at frequencies 200, 270, 350, and 600 GHz to separate the CMB from polarized dust emission within the Galaxy. A series of flights alternating between northern and southern hemisphere launch sites will produce nearly full-sky maps in Stokes I, Q, U, and V. I will discuss the current status and potential science returns from the PIPER project.

  7. Adsorption behavior and current-voltage characteristics of CdSe nanocrystals on hydrogen-passivated silicon

    DEFF Research Database (Denmark)

    Walzer, Karsten; Quaade, Ulrich; Ginger, D.S.

    2002-01-01

    Using scanning tunneling microscopy and spectroscopy we have studied both the geometric distribution and the conduction properties of organic shell capped CdSe nanocrystals adsorbed on hydrogen-passivated Si(100). At submonolayer concentrations, the nanocrystal distribution on the surface was found...... found that the current through the MIS junction is limited by the nanocrystals only in one bias direction, while in the other bias direction the current is limited by the semiconducting substrate. This property may be of relevance for the construction of hybrid electronic devices combining semiconductor...... electrodes with nanoscale elements such as nanocrystals or organic molecules....

  8. High energy behavior of a six-point R-current correlator in N=4 supersymmetric Yang-Mills theory

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, Jochen; Hentschinski, Martin; Mischler, Anna-Maria [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Ewerz, Carlo [Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik; GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany). ExtreMe Matter Institute EMMI; Bielefeld Univ. (Germany). Fakultaet fuer Physik; European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT), Villazzano (Italy)

    2009-12-15

    We study the high energy limit of a six-point R-current correlator in N=4 supersymmetric Yang-Mills theory for finite N{sub c}. We make use of the framework of perturbative resummation of large logarithms of the energy. More specifically, we apply the (extended) generalized leading logarithmic approximation. We find that the same conformally invariant two-to-four gluon vertex occurs as in non-supersymmetric Yang-Mills theory. As a new feature we find a direct coupling of the four-gluon t-channel state to the R-current impact factor. (orig.)

  9. High energy behavior of a six-point R-current correlator in N=4 supersymmetric Yang-Mills theory

    International Nuclear Information System (INIS)

    Bartels, Jochen; Hentschinski, Martin; Mischler, Anna-Maria

    2009-12-01

    We study the high energy limit of a six-point R-current correlator in N=4 supersymmetric Yang-Mills theory for finite N c . We make use of the framework of perturbative resummation of large logarithms of the energy. More specifically, we apply the (extended) generalized leading logarithmic approximation. We find that the same conformally invariant two-to-four gluon vertex occurs as in non-supersymmetric Yang-Mills theory. As a new feature we find a direct coupling of the four-gluon t-channel state to the R-current impact factor. (orig.)

  10. Polarized Light Corridor Demonstrations.

    Science.gov (United States)

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  11. Tax Accounting and Reporting Behavior: Empirical Evidence on the Effects of Book-Tax Conformity and Current Trends in Europe

    OpenAIRE

    Meier, Ina

    2017-01-01

    This dissertation deals with the topic of of Book-Tax Conformity, i.e. the degree to which book and tax accounting should be aligned. The aim is to provide further evidence on the research question of the true effects and characteristics of one-book and two-book systems and their effects on firms reporting behavior as well as to derive propositions on the appropriate degree of book-tax conformity. In addition, supranational trends and economic influencing factors which might prospectively aff...

  12. Behavior of A NbTi very fine filament composite with current feed in the technical range

    International Nuclear Information System (INIS)

    Asdente, M.; Ottoboni, V.; Ripamonti, G.; Zannella, S.

    1985-01-01

    Self-field losses have been measured on a NbTi multifilamentary wire with very fine filaments suitable for use in ac superconducting equipment working at industrial frequency. The loss trends as functions of current intensity and frequency as well as the comparison of the losses in a coil show that they are essentially of hysteretic nature

  13. Current Crisis in Science Education? Women in Science and Problems for the Behavioral Scientists. Some Perspectives of a Physicist.

    Science.gov (United States)

    Dresselhaus, Mildred S.

    A number of problems exist in society which require the cooperation of physical and social scientists. One of these problems is the current crisis in science education. There are several aspects to this problem, including the declining interest of students in math and science at a time when functioning in our society requires more, not less,…

  14. Current limiting behavior in three-phase transformer-type SFCLs using an iron core according to variety of fault

    Science.gov (United States)

    Cho, Yong-Sun; Jung, Byung-Ik; Ha, Kyoung-Hun; Choi, Soo-Geun; Park, Hyoung-Min; Choi, Hyo-Sang

    To apply the superconducting fault current limiter (SFCL) to the power system, the reliability of the fault-current-limiting operation must be ensured in diverse fault conditions. The SFCL must also be linked to the operation of the high-speed recloser in the power system. In this study, a three-phase transformer-type SFCL, which has a neutral line to improve the simultaneous quench characteristics of superconducting elements, was manufactured to analyze the fault-current-limiting characteristic according to the single, double, and triple line-to-ground faults. The transformer-type SFCL, wherein three-phase windings are connected to one iron core, reduced the burden on the superconducting element as the superconducting element on the sound phase was also quenched in the case of the single line-to-ground fault. In the case of double or triple line-to-ground faults, the flux from the faulted phase winding was interlinked with other faulted or sound phase windings, and the fault-current-limiting rate decreased because the windings of three phases were inductively connected by one iron core.

  15. Polarization versus Temperature in Pyridinium Ionic Liquids

    DEFF Research Database (Denmark)

    Chaban, V. V.; Prezhdo, O. V.

    2014-01-01

    Electronic polarization and charge transfer effects play a crucial role in thermodynamic, structural, and transport properties of room-temperature ionic liquids (RTILs). These nonadditive interactions constitute a useful tool for tuning physical chemical behavior of RTILs. Polarization and charge...... electronic density description for a cationanion pair. Atom-centered density matrix propagation molecular dynamics, supplemented by a weak coupling to an external bath, is used to simulate the temperature impact on system properties. We show that, quite surprisingly, nonadditivity in the cationanion...

  16. Polarized Moessbauer transitions

    International Nuclear Information System (INIS)

    Barb, D.

    1975-01-01

    Theoretical aspects of the emission, absorption and scattering of polarized gamma rays are reviewed for a general case of combined magnetic and electric hyperfine interactions; various possibilities of obtaining polarized gamma sources are described and examples are given of the applications of Moessbauer spectroscopy with polarized gamma rays in solving problems of solid state physics. (A.K.)

  17. Brane polarization is no cure for tachyons

    OpenAIRE

    Bena, Iosif; Kuperstein, Stanislav

    2015-01-01

    Anti-M2 and anti-D3 branes placed in regions with charges dissolved in fluxes have a tachyon in their near-horizon region, which causes these branes to repel each other. If the branes are on the Coulomb branch this tachyon gives rise to a runaway behavior, but when the branes are polarized into five-branes this tachyon only appears to lower the energy of the polarized branes, without affecting its stability. We analyze brane polarization in the presence of a brane-brane-repelling tachyon and ...

  18. The Effect of Elite Polarization: A Comparative Perspective on How Party Elites Influence Attitudes and Behavior on Climate Change in the European Union

    Directory of Open Access Journals (Sweden)

    Jacob Sohlberg

    2016-12-01

    Full Text Available There is considerable variability in attitudes towards climate change between citizens of different countries. By using individual-level and country-level data, I examine if this variability in public opinion is partially caused by political party elites. The results show that when elites are united in their support for environmental issues, the perceived threat of climate change is higher than in countries where party elites are divided. The results also demonstrate that the perceived threat influences behavior related to climate change, and that threat mediates the effect of party positions. Consequently, the effect of party elites is stronger than previously acknowledged. The models rely on Generalized Method of Moments estimation and instrumental variables with clustering on EU member-states.

  19. An experimental investigation of chemical communication in the polar bear

    Science.gov (United States)

    Owen, Megan A.; Swaisgood, Ronald R.; Slocomb, C.; Amstrup, Steven C.; Durner, George M.; Simac, Kristin S.; Pessier, Allan P.

    2015-01-01

    The polar bear (Ursus maritimus), with its wide-ranging movements, solitary existence and seasonal reproduction, is expected to favor chemosignaling over other communication modalities. However, the topography of its Arctic sea ice habitat is generally lacking in stationary vertical substrates routinely used for targeted scent marking in other bears. These environmental constraints may have shaped a marking strategy, unique to polar bears, for widely dispersed continuous dissemination of scent via foot pads. To investigate the role of chemical communication, pedal scents were collected from free-ranging polar bears of different sex and reproductive classes captured on spring sea ice in the Beaufort and Chukchi seas, and presented in a controlled fashion to 26 bears in zoos. Results from behavioral bioassays indicated that bears, especially females, were more likely to approach conspecific scent during the spring than the fall. Male flehmen behavior, indicative of chemosignal delivery to the vomeronasal organ, differentiated scent donor by sex and reproductive condition. Histologic examination of pedal skin collected from two females indicated prominent and profuse apocrine glands in association with large compound hair follicles, suggesting that they may produce scents that function as chemosignals. These results suggest that pedal scent, regardless of origin, conveys information to conspecifics that may facilitate social and reproductive behavior, and that chemical communication in this species has been adaptively shaped by environmental constraints of its habitat. However, continuously distributed scent signals necessary for breeding behavior may prove less effective if current and future environmental conditions cause disruption of scent trails due to increased fracturing of sea ice.

  20. Current Age, Age at First Sex, Age at First Homelessness, and HIV Risk Perceptions Predict Sexual Risk Behaviors among Sexually Active Homeless Adults.

    Science.gov (United States)

    Santa Maria, Diane; Hernandez, Daphne C; Arlinghaus, Katherine R; Gallardo, Kathryn R; Maness, Sarah B; Kendzor, Darla E; Reitzel, Lorraine R; Businelle, Michael S

    2018-01-26

    While HIV disproportionately impacts homeless individuals, little is known about the prevalence of HIV risk behaviors in the southwest and how age factors and HIV risk perceptions influence sexual risk behaviors. We conducted a secondary data analysis ( n = 460) on sexually active homeless adults from a cross-sectional study of participants ( n = 610) recruited from homeless service locations, such as shelters and drop-in centers, in an understudied region of the southwest. Covariate-adjusted logistic regressions were used to assess the impact of age at homelessness onset, current age, age at first sex, and HIV risk perceptions on having condomless sex, new sexual partner(s), and multiple sexual partners (≥4 sexual partners) in the past 12 months. Individuals who first experienced homelessness by age 24 were significantly more likely to report condomless sex and multiple sexual partners in the past year than those who had a later onset of their first episode of homelessness. Individuals who were currently 24 years or younger were more likely to have had condomless sex, new sexual partners, and multiple sexual partners in the past 12 months than those who were 25 years or older. Those who had low perceived HIV risk had lower odds of all three sexual risk behaviors. Social service and healthcare providers should consider a younger age at homelessness onset when targeting HIV prevention services to youth experiencing homelessness.

  1. Current Age, Age at First Sex, Age at First Homelessness, and HIV Risk Perceptions Predict Sexual Risk Behaviors among Sexually Active Homeless Adults

    Directory of Open Access Journals (Sweden)

    Diane Santa Maria

    2018-01-01

    Full Text Available While HIV disproportionately impacts homeless individuals, little is known about the prevalence of HIV risk behaviors in the southwest and how age factors and HIV risk perceptions influence sexual risk behaviors. We conducted a secondary data analysis (n = 460 on sexually active homeless adults from a cross-sectional study of participants (n = 610 recruited from homeless service locations, such as shelters and drop-in centers, in an understudied region of the southwest. Covariate-adjusted logistic regressions were used to assess the impact of age at homelessness onset, current age, age at first sex, and HIV risk perceptions on having condomless sex, new sexual partner(s, and multiple sexual partners (≥4 sexual partners in the past 12 months. Individuals who first experienced homelessness by age 24 were significantly more likely to report condomless sex and multiple sexual partners in the past year than those who had a later onset of their first episode of homelessness. Individuals who were currently 24 years or younger were more likely to have had condomless sex, new sexual partners, and multiple sexual partners in the past 12 months than those who were 25 years or older. Those who had low perceived HIV risk had lower odds of all three sexual risk behaviors. Social service and healthcare providers should consider a younger age at homelessness onset when targeting HIV prevention services to youth experiencing homelessness.

  2. Behavior of current sheets at directional magnetic discontinuities in the solar wind at 0.72 AU

    Czech Academy of Sciences Publication Activity Database

    Zhang, T. L.; Russell, C. T.; Zambelli, W.; Vörös, Zoltán; Wang, C.; Cao, J. B.; Jian l, L. K.; Strangeway, R. J.; Balikhin, M.; Baumjohann, W.; Delva, M.; Volwerk, M.; Glassmeier, K.; H.

    2008-01-01

    Roč. 35, č. 24 (2008), L24102/1-L24102/5 ISSN 0094-8276 Grant - others:Austrian Wissenschaftfonds(AT) P20131-N16; NNSFC(CN) 40628003; 973 Program(CN) 2006CB806305; NASA (US) NNG06GC62G Institutional research plan: CEZ:AV0Z30420517 Keywords : solar wind * current sheets * magnetic annihilation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.959, year: 2008

  3. A new model for turbidity current behavior based on integration of flow monitoring and precision coring in a submarine canyon

    Science.gov (United States)

    Symons, William O.; Sumner, Esther J.; Paull, Charles K.; Cartigny, Matthieu J.B.; Xu, Jingping; Maier, Katherine L.; Lorenson, Thomas; Talling, Peter J.

    2017-01-01

    Submarine turbidity currents create some of the largest sediment accumulations on Earth, yet there are few direct measurements of these flows. Instead, most of our understanding of turbidity currents results from analyzing their deposits in the sedimentary record. However, the lack of direct flow measurements means that there is considerable debate regarding how to interpret flow properties from ancient deposits. This novel study combines detailed flow monitoring with unusually precisely located cores at different heights, and multiple locations, within the Monterey submarine canyon, offshore California, USA. Dating demonstrates that the cores include the time interval that flows were monitored in the canyon, albeit individual layers cannot be tied to specific flows. There is good correlation between grain sizes collected by traps within the flow and grain sizes measured in cores from similar heights on the canyon walls. Synthesis of flow and deposit data suggests that turbidity currents sourced from the upper reaches of Monterey Canyon comprise three flow phases. Initially, a thin (38–50 m) powerful flow in the upper canyon can transport, tilt, and break the most proximal moorings and deposit chaotic sands and gravel on the canyon floor. The initially thin flow front then thickens and deposits interbedded sands and silty muds on the canyon walls as much as 62 m above the canyon floor. Finally, the flow thickens along its length, thus lofting silty mud and depositing it at greater altitudes than the previous deposits and in excess of 70 m altitude.

  4. Charging effects of MgO under electron bombardment and nonohmic behavior of the induced specimen current

    International Nuclear Information System (INIS)

    Cazaux, J.; Kim, K.H.; Jbara, O.; Salace, G.

    1991-01-01

    A MgO single crystal partly coated with a thin layer of Ag was irradiated with incident electrons while the time evolution of the surface potential and specimen current were recorded. A zero surface potential, V s , is measured when the uncoated part of the specimen is irradiated, while the potential is very negative on the coated part for primary beam energies in the 2--5 keV range. The results invalidate the usual approach which uses a theoretical total yield curve for evaluating the sign of the surface potential as well as the use of an ohm law V s = RI s for correlating the surface potential V s and the specimen current I s . Explanations of the observed phenomena are suggested and their correlation with the secondary electron emission of insulators is indicated. One surprising result is the possibility of injecting (nonohmic) current densities of 1 mA/mm 2 or greater into insulators having electrical resistivities of 10 15 Ω cm

  5. Recalled and current gender role behavior, gender identity and sexual orientation in adults with Disorders/Differences of Sex Development.

    Science.gov (United States)

    Callens, Nina; Van Kuyk, Maaike; van Kuppenveld, Jet H; Drop, Stenvert L S; Cohen-Kettenis, Peggy T; Dessens, Arianne B

    2016-11-01

    The magnitude of sex differences in human brain and behavior and the respective contributions of biology versus socialization remain a topic of ongoing study in science. The preponderance of evidence attests to the notion that sexual differentiation processes are at least partially hormonally mediated, with high levels of prenatal androgens facilitating male-typed and inhibiting female-typed behaviors. In individuals with Disorders/Differences of Sex Development (DSD), hormonal profiles or sensitivities have been altered due to genetic influences, presumably affecting gender(ed) activity interests as well as gender identity development in a minority of the affected population. While continued postnatal androgen exposure in a number of DSD syndromes has been associated with higher rates of gender dysphoria and gender change, the role of a number of mediating and moderating factors, such as initial gender assignment, syndrome severity and clinical management remains largely unclear. Limited investigations of the associations between these identified influences and gendered development outcomes impede optimization of clinical care. Participants with DSD (n=123), recruited in the context of a Dutch multi-center follow-up audit, were divided in subgroups reflecting prenatal androgen exposure, genital appearance at birth and gender of rearing. Recalled childhood play and playmate preferences, gender identity and sexual orientation were measured with questionnaires and semi-structured interviews. Data were compared to those of control male (n=46) and female participants (n=79). The findings support that (a) prenatal androgen exposure has large effects on (gendered) activity interests, but to a much lesser extent on sexual orientation and that (b) initial gender of rearing remains a better predictor of gender identity contentedness than prenatal androgen exposure, beyond syndrome severity and medical treatment influences. Nonetheless, 3.3% of individuals with DSD in our

  6. Influence of quarter-wave retarder parameters on performance of fiber-optic current sensor

    Science.gov (United States)

    Kostritskii, S. M.; Korkishko, Yu. N.; Fedorov, V. A.; Mitrokhin, V. P.

    2014-05-01

    Temperature stability of magneto-optic sensor at a marked transient temperature gradient has been investigated. Our experimental study leads to the conclusion that the polarized gyro architecture with two quarter-wave retarders on the opposite sides of the fiber loop of Sagnac interferometer must be used to obtain a fiber-optic current sensor with the lowdrift behavior.

  7. Characterization of polarized THP-1 macrophages and polarizing ability of LPS and food compounds

    NARCIS (Netherlands)

    Chanput, W.; Mes, J.J.; Savelkoul, H.F.J.; Wichers, H.J.

    2013-01-01

    Little is known about the polarizing potential of currently used human macrophage cell lines, while a better understanding phenomena can support the prediction of effects in vivo based on in vitro analysis. To test the polarization capability of PMA differentiated-THP-1 macrophages (M0), cells were

  8. The Physics of Polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  9. Performance of a plasma opening switch in positive polarity on Gamble I using flashboard plasma sources

    International Nuclear Information System (INIS)

    Renk, T.J.

    1995-01-01

    The successful development of the Plasma Opening Switch (POS) for inductive storage applications has been largely confined to negative polarity operation. Some models of POS behavior suggest that this is because in a positive polarity coaxial configuration, the weaker magnetic field at the cathode position retards the switch opening process. This article describes experiments in which both conductor radii in the POS region were significantly reduced. Anode- and cathode-side current monitors indicate that voltages greater than open-circuit are generated at the POS position, but there is a significant amount of electron flow out of the POS, depending upon load impedance. Flow impedance analysis indicates that a relatively small gap appears in the POS plasma after switch opening. Switch performance is also compared between flashboard and carbon gun plasma sources, with the latter operated both in positive and negative polarity

  10. Behavior of impurity ion velocities during the pulsed poloidal current drive in the Madison symmetric torus reversed-field pinch

    International Nuclear Information System (INIS)

    Sakakita, Hajime; Craig, Darren; Anderson, Jay K.; Chapman, Brett E.; Den-Hartog, Daniel J.; Prager, Stewart C.; Biewer, Ted M.; Terry, Stephen D.

    2003-01-01

    We report on passive measurements of impurity ion velocities during the pulsed poloidal current drive (PPCD) in the Madison Symmetric Torus reversed-field pinch. During PPCD, the electron temperature increased and a sudden reduction of magnetic fluctuations was observed. For this change, we have studied whether plasma velocity is affected. Plasma rotation is observed to decrease during PPCD. From measurements of line intensities for several impurities at 10 poloidal chords, it is found that the impurity line emission shifts outward. The ion temperature of impurities is reasonably connected to that measured by charge exchange recombination spectroscopy from core to edge. (author)

  11. Climate change and the increasing impact of polar bears on bird populations

    Directory of Open Access Journals (Sweden)

    Jouke eProp

    2015-03-01

    Full Text Available The Arctic is becoming warmer at a high rate, and contractions in the extent of sea ice are currently changing the habitats of marine top-predators dependent on ice. Polar bears (Ursus maritimus depend on sea ice for hunting seals. For these top-predators, longer ice-free seasons are hypothesized to force the bears to hunt for alternative terrestrial food, such as eggs from colonial breeding birds. We analyzed time-series of polar bear observations at four locations on Spitsbergen (Svalbard and one in east Greenland. Summer occurrence of polar bears, measured as the probability of encountering bears and the number of days with bear presence, has increased significantly from the 1970/80s to the present. The shifts in polar bear occurrence coincided with trends for shorter sea ice seasons and less sea ice during the spring in the study area. This resulted in a strong inverse relationship between the probability of bear encounters on land and the length of the sea ice season. Within ten years after their first appearance on land, polar bears had advanced their arrival dates by almost 30 days. Direct observations of nest predation showed that polar bears may severely affect reproductive success of the barnacle goose (Branta leucopsis, common eider (Somateria mollissima and glaucous gull (Larus hyperboreus. Nest predation was strongest in years when the polar bears arrived well before hatch, with more than 90% of all nests being predated. The results are similar to findings from Canada, and large-scale processes, such as climate and subsequent habitat changes, are pinpointed as the most likely drivers in various parts of the Arctic. We suggest that the increasing, earlier appearance of bears on land in summer reflects behavioral adaptations by a small segment of the population to cope with a reduced hunting range on sea ice. This exemplifies how behavioral adaptations may contribute to the cascading effects of climate change.

  12. The National Acupuncture Detoxification Association protocol, auricular acupuncture to support patients with substance abuse and behavioral health disorders: current perspectives

    Directory of Open Access Journals (Sweden)

    Stuyt EB

    2016-12-01

    Full Text Available Elizabeth B Stuyt,1 Claudia A Voyles2 1Department of Psychiatry, University of Colorado Health Sciences Center, Pueblo, CO, 2Department of Clinical Studies, AOMA Graduate School of Integrative Medicine, Austin, TX, USA Abstract: The National Acupuncture Detoxification Association (NADA-standardized 3- to 5-point ear acupuncture protocol, born of a community-minded response to turbulent times not unlike today, has evolved into the most widely implemented acupuncture-assisted protocol, not only for substance abuse, but also for broad behavioral health applications. This evolution happened despite inconsistent research support. This review highlights the history of the protocol and the research that followed its development. Promising, early randomized-controlled trials were followed by a mixed field of positive and negative studies that may serve as a whole to prove that NADA, despite its apparent simplicity, is neither a reductive nor an independent treatment, and the need to refine the research approaches. Particularly focusing on the last decade and its array of trials that elucidate aspects of NADA application and effects, the authors recommend that, going forward, research continues to explore the comparison of the NADA protocol added to accepted treatments to those treatments alone, recognizing that it is not a stand-alone procedure but a psychosocial intervention that affects the whole person and can augment outcomes from other treatment modalities. Keywords: National Acupuncture Detoxification Association (NADA, ear acupuncture, acudetox, addiction, mental health, trauma

  13. Role of polaron hopping in leakage current behavior of a SrTiO{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Y., E-mail: yxc238@psu.edu; Randall, C. A.; Chen, L. Q. [Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802 (United States); Bhattacharya, S. [Department of Materials Science and Engineering, Indian Institute of Technology Hyderabad, YM 502205 (India); Shen, J. [Department of Mathematics, Purdue University, West Lafayette, Indiana 47907 (United States)

    2013-12-14

    We studied the ionic/electronic transport and resistance degradation behavior of dielectric oxides by solving the electrochemical transport equations. Here, we took into account the non-periodical boundary conditions for the transport equations using the Chebyshev collocation algorithm. A sandwiched Ni|SrTiO{sub 3}|Ni capacitor is considered as an example under the condition of 1.0 V, 1.0 μm thickness for SrTiO{sub 3} layer, and a temperature of 150 °C. The applied voltage resulted in the migration of ionic defects (oxygen vacancies) from anode towards cathode. The simulated electric potential profile at steady state is in good agreement with the recent experimental observation. We introduced the possibility of polaron-hopping between Ti{sup 3+} and Ti{sup 4+} at the electrode interface. It is shown that both the oxygen vacancy transport and the polaron-hopping contribute to the resistance degradation of single crystal SrTiO{sub 3}, which is consistent with the experimental observations.

  14. Increased Arctic Sea Ice Drift Alters Polar Bear Movements and Energetics

    Science.gov (United States)

    Douglas, D. C.; Durner, G. M.; Albeke, S. E.; Whiteman, J. P.; Amstrup, S. C.; Richardson, E.; Wilson, R. R.; Ben-David, M.

    2015-12-01

    Recent thinning of Arctic sea ice has increased its drift from currents and winds. Increased ice drift could affect movements and energy balance of polar bears (Ursus maritimus) which rely, almost exclusively, on this substrate for hunting seals. Foraging by polar bears is a relatively sedentary behavior, as they typically capture their main prey by waiting at breathing holes, where seals haul-out along leads, or by short-distance stalking. We examined the response of polar bears to ice drift in the Beaufort (BS) and Chukchi (CS) seas, and between two periods with different sea ice characteristics: 1987-1998 and 1999-2013. We used satellite-tracked adult female polar bear locations, standardized by a continuous-time correlated random walk, coupled with modeled ice drift, to estimate displacement and drift-corrected bear movements along east-west and north-south axes. Sea ice drift in both regions increased with greater westward and more extreme northward and southward rates from 1987-1998 to 1999-2013. Polar bears responded with greater eastward movements and, in the CS greater movements north and south. We show that efforts by polar bears to compensate for greater westward ice drift in recent years translated into a model-derived estimate of 5.7-7.2% increase in energy expenditure. We also estimated that polar bears increased their travel time 18-20% between the two time periods, suggesting time allocated to foraging was reduced. Increased energetic costs and travel time resulting from greater ice drift, in conjunction with ongoing habitat loss, suggest that recent changes to Arctic sea ice may affect movements and energy balance of polar bears.

  15. Perceived discrimination, psychological distress, and current smoking status: results from the Behavioral Risk Factor Surveillance System Reactions to Race module, 2004-2008.

    Science.gov (United States)

    Purnell, Jason Q; Peppone, Luke J; Alcaraz, Kassandra; McQueen, Amy; Guido, Joseph J; Carroll, Jennifer K; Shacham, Enbal; Morrow, Gary R

    2012-05-01

    We examined the association between perceived discrimination and smoking status and whether psychological distress mediated this relationship in a large, multiethnic sample. We used 2004 through 2008 data from the Behavioral Risk Factor Surveillance System Reactions to Race module to conduct multivariate logistic regression analyses and tests of mediation examining associations between perceived discrimination in health care and workplace settings, psychological distress, and current smoking status. Regardless of race/ethnicity, perceived discrimination was associated with increased odds of current smoking. Psychological distress was also a significant mediator of the discrimination-smoking association. Our results indicate that individuals who report discriminatory treatment in multiple domains may be more likely to smoke, in part, because of the psychological distress associated with such treatment.

  16. Solubilization of a polar oil used in nuclear industry by amphiphilic tri-block copolymers solutions. Relation between structure and behavior by proton nuclear magnetic resonance and small angle neutron scattering

    International Nuclear Information System (INIS)

    Causse, J.

    2005-01-01

    The first step in a decommissioning operation of a nuclear plant concerns the nuclear decontamination of various surfaces. More and more techniques developed for nuclear decontamination use soluble surfactants in aqueous solution with suitable chemical reagents. In most cases decontamination is based on the removal of a surface layer containing most of the activity (grease, organic deposits, paint, oxide layer...). The Tributylphosphate (TBP), a polar oil, is widely used as a complexing agent of Plutonium and Uranium in nuclear industry. This lipophilic compound, containing radioactive residues, strongly sticks on many surfaces. This organic layer is resistant to all classical treatments. Micellar systems proved to be efficient to pull TBP away and solubilize it so as to make easier its draining. In this study, Amphiphilic tri-block copolymers, referred to as Pluronics (polyethylene(oxide) - polypropylene(oxide) - polyethylene(oxide), (EO) n PO) m EO) n ) have been selected as polymeric amphiphiles so as to solubilize TBP in their supramolecular aggregates above the critical aggregation concentration. A first systematic study of the phase behavior of various three components systems (TBP-Water-Pluronic) by turbidity showed the particular behavior of one copolymer (the L64, (EO) 13 PO) 30 EO) 13 ), especially its very high TBP solubilization capacity. Consequently, the main part of this thesis has been devoted to the structural characterization of this micellar system (TBP-Water-L64) using 1 H NMR and SANS measurements. 1 H NMR gave information on the chemical environment of each component in the mixture and especially allowed hypothesis on the TBP location in the copolymer aggregates to be drawn. Direct structural information (size, shape, correlations) were obtained by SANS. Both experimental technique were proved to be very complementary and allowed a structural evolution of the aggregates following addition of TBP in the system to be evidenced. (author)

  17. Temperature-dependent leakage current behavior of epitaxial Bi0.5Na0.5TiO3-based thin films made by pulsed laser deposition

    Science.gov (United States)

    Hejazi, M. M.; Safari, A.

    2011-11-01

    This paper discusses the electrical conduction mechanisms in a 0.88 Bi0.5Na0.5TiO3-0.08 Bi0.5K0.5TiO3-0.04 BaTiO3 thin film in the temperature range of 200-350 K. The film was deposited on a SrRuO3/SrTiO3 substrate by pulsed laser deposition technique. At all measurement temperatures, the leakage current behavior of the film matched well with the Lampert's triangle bounded by three straight lines of different slopes. The relative location of the triangle sides varied with temperature due to its effect on the density of charge carriers and un-filled traps. At low electric fields, the ohmic conduction governed the leakage mechanism. The calculated activation energy of the trap is 0.19 eV implying the presence of shallow traps in the film. With increasing the applied field, an abrupt increase in the leakage current was observed. This was attributed to a trap-filling process by the injected carriers. At sufficiently high electric fields, the leakage current obeyed the Child's trap-free square law suggesting the space charge limited current was the dominant mechanism.

  18. Electron-Spin Filters Would Offer Spin Polarization Greater than 1

    Science.gov (United States)

    Ting, David Z.

    2009-01-01

    A proposal has been made to develop devices that would generate spin-polarized electron currents characterized by polarization ratios having magnitudes in excess of 1. Heretofore, such devices (denoted, variously, as spin injectors, spin polarizers, and spin filters) have typically offered polarization ratios having magnitudes in the approximate range of 0.01 to 0.1. The proposed devices could be useful as efficient sources of spin-polarized electron currents for research on spintronics and development of practical spintronic devices.

  19. [Review] Polarization and Polarimetry

    Science.gov (United States)

    Trippe, Sascha

    2014-02-01

    Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible multiple astrophysical discoveries. In this article I review (i) the physical basics of polarization: electromagnetic waves, photons, and parameterizations; (ii) astrophysical sources of polarization: scattering, synchrotron radiation, active media, and the Zeeman, Goldreich-Kylafis, and Hanle effects, as well as interactions between polarization and matter (like birefringence, Faraday rotation, or the Chandrasekhar-Fermi effect); (iii) observational methodology: on-sky geometry, influence of atmosphere and instrumental polarization, polarization statistics, and observational techniques for radio, optical, and X/γ wavelengths; and (iv) science cases for astronomical polarimetry: solar and stellar physics, planetary system bodies, interstellar matter, astrobiology, astronomical masers, pulsars, galactic magnetic fields, gamma-ray bursts, active galactic nuclei, and cosmic microwave background radiation.

  20. Zn2(+)-induced subconductance events in cardiac Na+ channels prolonged by batrachotoxin. Current-voltage behavior and single-channel kinetics

    Science.gov (United States)

    1991-01-01

    The mechanism of voltage-dependent substate production by external Zn2+ in batrachotoxin-modified Na+ channels from canine heart was investigated by analysis of the current-voltage behavior and single- channel kinetics of substate events. At the single-channel level the addition of external Zn2+ results in an increasing frequency of substate events with a mean duration of approximately 15-25 ms for the substate dwell time observed in the range of -70 to +70 mV. Under conditions of symmetrical 0.2 M NaCl, the open state of cardiac Na+ channels displays ohmic current-voltage behavior in the range of -90 to +100 mV, with a slope conductance of 21 pS. In contrast, the Zn2(+)- induced substate exhibits significant outward rectification with a slope conductance of 3.1 pS in the range of -100 to -50 mV and 5.1 pS in the range of +50 to +100 mV. Analysis of dwell-time histograms of substate events as a function of Zn2+ concentration and voltage led to the consideration of two types of models that may explain this behavior. Using a simple one-site blocking model, the apparent association rate for Zn2+ binding is more strongly voltage dependent (decreasing e-fold per +60 mV) than the Zn2+ dissociation rate (increasing e-fold per +420 mV). However, this simple blocking model cannot account for the dependence of the apparent dissociation rate on Zn2+ concentration. To explain this result, a four-state kinetic scheme involving a Zn2(+)-induced conformational change from a high conductance conformation to a substate conformation is proposed. This model, similar to one introduced by Pietrobon et al. (1989. J. Gen. Physiol. 94:1-24) for H(+)-induced substate behavior in L-type Ca2+ channels, is able to simulate the kinetic and equilibrium behavior of the primary Zn2(+)-induced substate process in heart Na+ channels. This model implies that binding of Zn2+ greatly enhances conversion of the open, ohmic channel to a low conductance conformation with an asymmetric energy profile for

  1. Numerical investigation on the dynamics and evolution mechanisms of multiple-current-pulse behavior in homogeneous helium dielectric-barrier discharges at atmospheric pressure

    Science.gov (United States)

    Zhang, Yuhui; Ning, Wenjun; Dai, Dong

    2018-03-01

    A systematic investigation on the dynamics and evolution mechanisms of multiple-current-pulse (MCP) behavior in homogeneous dielectric barrier discharge (HDBD) is carried out via fluid modelling. Inspecting the simulation results, two typical discharge regimes, namely the MCP-Townsend regime and MCP-glow regime, are found prevailing in MCP discharges, each with distinctive electrical and dynamic properties. Moreover, the evolution of MCP behavior with external parameters altering are illustrated and explicitly discussed. It is revealed that the discharge undergoes some different stages as external parameters vary, and the discharge in each stage follows a series of distinctive pattern in morphological characteristics and evolution trends. Among those stages, the pulse number per half cycle is perceived to observe non-monotonic variations with applied voltage amplitude (Vam) and gap width (dg) increasing, and a merging effect among pulses, mainly induced by the enhanced contribution of sinusoidal component to the total current, is considered responsible for such phenomenon. The variation of incipient discharge peak phase (Φpm) is dominated by the value of Vam as well as the proportion of total applied voltage that drops across the gas gap. Moreover, an abnormal, dramatic elevation in Jpm with dg increasing is observed, which could be evinced by the strengthened glow discharge structure and therefore enhanced space charge effect.

  2. Numerical investigation on the dynamics and evolution mechanisms of multiple-current-pulse behavior in homogeneous helium dielectric-barrier discharges at atmospheric pressure

    Directory of Open Access Journals (Sweden)

    Yuhui Zhang

    2018-03-01

    Full Text Available A systematic investigation on the dynamics and evolution mechanisms of multiple-current-pulse (MCP behavior in homogeneous dielectric barrier discharge (HDBD is carried out via fluid modelling. Inspecting the simulation results, two typical discharge regimes, namely the MCP-Townsend regime and MCP-glow regime, are found prevailing in MCP discharges, each with distinctive electrical and dynamic properties. Moreover, the evolution of MCP behavior with external parameters altering are illustrated and explicitly discussed. It is revealed that the discharge undergoes some different stages as external parameters vary, and the discharge in each stage follows a series of distinctive pattern in morphological characteristics and evolution trends. Among those stages, the pulse number per half cycle is perceived to observe non-monotonic variations with applied voltage amplitude (Vam and gap width (dg increasing, and a merging effect among pulses, mainly induced by the enhanced contribution of sinusoidal component to the total current, is considered responsible for such phenomenon. The variation of incipient discharge peak phase (Φpm is dominated by the value of Vam as well as the proportion of total applied voltage that drops across the gas gap. Moreover, an abnormal, dramatic elevation in Jpm with dg increasing is observed, which could be evinced by the strengthened glow discharge structure and therefore enhanced space charge effect.

  3. Cosmic Microwave Background Polarization and Inflation

    Science.gov (United States)

    Chuss, David T.

    2011-01-01

    Measurements of the cosmic microwave background (CMB) offer a means to explore the universe at a very early epoch. Specifically, if the universe went through a brief period of exponential expansion called inflation as current data suggest, gravitational waves from this period would polarize the CMB in a specific pattern. At GSFC, we are currently working towards two experiments that work in concert to measure this polarization pattern in search of evidence for inflation. The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization at frequencies between 40 and 150 GHz from the Atacama Desert in Chile. The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne experiment that will make similar measurements at frequencies between 200 and 600 GHz.

  4. Behavior of Lithium Metal Anodes under Various Capacity Utilization and High Current Density in Lithium Metal Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Shuhong; Zheng, Jianming; Li, Qiuyan; Li, Xing; Engelhard, Mark H.; Cao, Ruiguo; Zhang, Ji-Guang; Xu, Wu

    2018-01-01

    Lithium (Li) metal batteries (LMBs) are regarded as the most promising power sources for electric vehicles. Besides the Li dendrite growth and low Li Coulombic efficiency, how to well match Li metal anode with a high loading (normally over 3.0 mAh cm-2) cathode is another key challenge to achieve the real high energy density battery. In this work, we systematically investigate the effects of the Li metal capacity usage in each cycle, manipulated by varying the cathode areal loading, on the stability of Li metal anode and the cycling performance of LMBs using the LiNi1/3Mn1/3Co1/3O2 (NMC) cathode and an additive-containing dual-salt/carbonate-solvent electrolyte. It is demonstrated that the Li||NMC cells show decent long-term cycling performance even with NMC areal capacity loading up to ca. 4.0 mAh cm-2 and at a charge current density of 1.0 mA cm-2. The increase of the Li capacity usage in each cycle causes variation in the components of the solid electrolyte interphase (SEI) layer on Li metal anode and generates more ionic conductive species from this electrolyte. Further study reveals for the first time that the degradation of Li metal anode and the thickness of SEI layer on Li anode show linear relationship with the areal capacity of NMC cathode. Meanwhile, the expansion rate of consumed Li and the ratio of SEI thickness to NMC areal loading are kept almost the same value with increasing cathode loading, respectively. These fundamental findings provide new perspectives on the rational evaluation of Li metal anode stability for the development of rechargeable LMBs.

  5. Polarized-neutron-scattering study of the spin-wave excitations in the 3-k ordered phase of uranium antimonide.

    Science.gov (United States)

    Magnani, N; Caciuffo, R; Lander, G H; Hiess, A; Regnault, L-P

    2010-03-24

    The anisotropy of magnetic fluctuations propagating along the [1 1 0] direction in the ordered phase of uranium antimonide has been studied using polarized inelastic neutron scattering. The observed polarization behavior of the spin waves is a natural consequence of the longitudinal 3-k magnetic structure; together with recent results on the 3-k-transverse uranium dioxide, these findings establish this technique as an important tool to study complex magnetic arrangements. Selected details of the magnon excitation spectra of USb have also been reinvestigated, indicating the need to revise the currently accepted theoretical picture for this material.

  6. Polarization feedback laser stabilization

    Science.gov (United States)

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  7. Exploring Science Through Polar Exploration

    Science.gov (United States)

    Pfirman, S. L.; Bell, R. E.; Zadoff, L.; Kelsey, R.

    2003-12-01

    Exploring the Poles is a First Year Seminar course taught at Barnard College, Columbia University. First Year Seminars are required of incoming students and are designed to encourage critical analysis in a small class setting with focused discussion. The class links historical polar exploration with current research in order to: introduce non-scientists to the value of environmental science through polar literature; discuss issues related to venturing into the unknown that are of relevance to any discipline: self-reliance, leadership, preparation, decisions under uncertainty; show students the human face of science; change attitudes about science and scientists; use data to engage students in exploring/understanding the environment and help them learn to draw conclusions from data; integrate research and education. These goals are met by bringing analysis of early exploration efforts together with a modern understanding of the polar environment. To date to class has followed the efforts of Nansen in the Fram, Scott and Amundsen in their race to the pole, and Shackleton's Endurance. As students read turn-of-the-century expedition journals, expedition progress is progressively revealed on an interactive map showing the environmental context. To bring the exploration process to life, students are assigned to expedition teams for specific years and the fates of the student "expeditions" are based on their own decisions. For example, in the Arctic, they navigate coastal sea ice and become frozen into the ice north of Siberia, re-creating Nansen's polar drift. Fates of the teams varied tremendously: some safely emerged at Fram Strait in 4 years, while others nearly became hopelessly lost in the Beaufort Gyre. Students thus learn about variability in the current polar environment through first hand experience, enabling them to appreciate the experiences, decisions, and, in some cases, the luck, of polar explorers. Evaluation by the Columbia Center for New Media, Teaching

  8. Physics with polarization at the SLD

    International Nuclear Information System (INIS)

    Burrows, P.N.

    1990-05-01

    The SLD detector is nearing completion and will start physics-quality data-taking at the SLC in 1991 with a longitudinally polarized electron beam and unpolarized positron beam. The current status of the detector is reviewed and the rich program of physics measurements possible with polarization and the SLD detector is briefly presented. In particular, the left-right polarization asymmetry, A LR , will be a unique measurement for the next few years and will allow tight bounds to be set upon the mass of the top quark. 14 refs., 1 fig

  9. Characterization of Partially Polarized Light Fields

    CERN Document Server

    Martínez-Herrero, Rosario; Piquero, Gemma

    2009-01-01

    Polarization involves the vectorial nature of light fields. In current applications of optical science, the electromagnetic description of light with its vector features has been shown to be essential: In practice, optical radiation also exhibits randomness and spatial non-uniformity of the polarization state. Moreover, propagation through photonic devices can alter the correlation properties of the light field, resulting in changes in polarization. All these vectorial properties have been gaining importance in recent years, and they are attracting increasing attention in the literature. This is the framework and the scope of the present book, which includes the authors’ own contributions to these issues.

  10. Airborne Laser Polarization Sensor

    Science.gov (United States)

    Kalshoven, James, Jr.; Dabney, Philip

    1991-01-01

    Instrument measures polarization characteristics of Earth at three wavelengths. Airborne Laser Polarization Sensor (ALPS) measures optical polarization characteristics of land surface. Designed to be flown at altitudes of approximately 300 m to minimize any polarizing or depolarizing effects of intervening atmosphere and to look along nadir to minimize any effects depending on look angle. Data from measurements used in conjunction with data from ground surveys and aircraft-mounted video recorders to refine mathematical models used in interpretation of higher-altitude polarimetric measurements of reflected sunlight.

  11. Belief polarization is not always irrational.

    Science.gov (United States)

    Jern, Alan; Chang, Kai-min K; Kemp, Charles

    2014-04-01

    Belief polarization occurs when 2 people with opposing prior beliefs both strengthen their beliefs after observing the same data. Many authors have cited belief polarization as evidence of irrational behavior. We show, however, that some instances of polarization are consistent with a normative account of belief revision. Our analysis uses Bayesian networks to characterize different kinds of relationships between hypotheses and data, and distinguishes between cases in which normative reasoners with opposing beliefs should both strengthen their beliefs, cases in which both should weaken their beliefs, and cases in which one should strengthen and the other should weaken his or her belief. We apply our analysis to several previous studies of belief polarization and present a new experiment that suggests that people tend to update their beliefs in the directions predicted by our normative account.

  12. Transcranial Direct Current Stimulation in Patients with Prolonged Disorders of Consciousness: Combined Behavioral and Event-Related Potential Evidence

    Directory of Open Access Journals (Sweden)

    Ye Zhang

    2017-11-01

    Full Text Available BackgroundThe electrophysiological evidence supporting the therapeutic efficacy of multiple transcranial direct current stimulation (tDCS sessions on consciousness improvement in patients with prolonged disorders of consciousness (DOCs has not been firmly established.ObjectivesTo assess the effects of repeated tDCS in patients with prolonged DOCs by Coma Recovery Scale-Revised (CRS-R score and event-related potential (ERP.MethodUsing a sham-controlled randomized double-blind design, 26 patients were randomly assigned to either a real [five vegetative state (VS and eight minimally conscious state (MCS patients] or sham (six VS and seven MCS patients stimulation group. The patients in the real stimulation group underwent 20 anodal tDCS sessions of the left dorsolateral prefrontal cortex (DLPFC over 10 consecutive working days. The CRS-R score and P300 amplitude and latency in a hierarchical cognitive assessment were recorded to evaluate the consciousness level before tDCS and immediately after the 20 sessions.ResultsThe intra-group CRS-R analysis revealed a clinically significant improvement in the MCS patients in the real stimulation group. The inter-group CRS-R analysis showed a significant difference in CRS-R between VS and MCS patients at baseline in both the real and sham stimulation groups. The intra-group ERP analysis revealed a significant increase in P300 amplitude after tDCS in the MCS patients in the real stimulation group, but no significant differences in P300 latency. For the inter-group ERP analysis, we observed significant differences regarding the presence of P300 at baseline between the VS and MCS patients in both groups.ConclusionThe repeated anodal tDCS of the left DLPFC could produce clinically significant improvements in MCS patients. The observed tDCS-related consciousness improvements might be related to improvements in attention resource allocation (reflected by the P300 amplitude. The findings support the use of tDCS in

  13. Advantages of polarization experiments at RHIC

    International Nuclear Information System (INIS)

    Underwood, D.G.

    1990-01-01

    We point out various spin experiments that could be done if the polarized beam option is pursued at RHIC. The advantages of RHIC for investigating several current and future physics problems are discussed. In particular, the gluon spin dependent structure function of the nucleon could be measured cleanly and systematically. Relevant experience developed in conjunction with the Fermilab Polarized Beam program is also presented. 8 refs., 2 tabs

  14. Latest on polarization in electron storage rings

    International Nuclear Information System (INIS)

    Chao, A.W.

    1983-01-01

    The field of beam polarization in electron storage rings is making rapid progress in recent several years. This report is an attempt to summarize some of these developments concerning how to produce and maintain a high level of beam polarization. Emphasized will be the ideas and current thoughts people have on what should and could be done on electron rings being designed at present such as HERA, LEP and TRISTAN. 23 references

  15. Semantic-enabled Spatiotemporal Web Portal for Polar Sciences

    Science.gov (United States)

    Liu, K.

    2014-12-01

    It is essential for Intergovernmental and scientists to study, monitor and analyze the geographic data in polar regions. Polarregions are likely to respond rapidly and more severely to the climate changesthan any other area on the Earth.They also have significant importance for Global warming research. The ocean water around the Antarctic and Arctic is a crucial part of the ocean's thermohaline circulation. The Polar Cyberinfrastructure Program was built to acquire, share, access, analyze the polar data for Arctic and Antarctic communities. The polar data are becoming big and bring challenges for Polar Cyberinfrastructure Program including: 1) it is difficultfor polar data users to discover most relevant data based on the understanding the behavior; 2) the quality of polar data service is essential to use the polar data, however, it varies for users in different locations and different time. The semantic enabled discovery and volunteer computing are used in the Polar Cyberinfrastructurefor tackling these challenges: 1) semantic search and knowledge reasoning to improve the discovery recall and precision of polar data; 2) volunteer computing is used to gather volunteers computing resources around the world to improve the quality evaluationaccuracy of polar data service. Keywords: Polar Science, Cyberinfrastructure, Semantic, Volunteer Computing

  16. Controlling vortex chirality and polarity by geometry in magnetic nanodots

    OpenAIRE

    Agramunt Puig, Sebastià

    2014-01-01

    The independent control of both vortex chirality and polarity is a significant challenge in magnetic devices based on nano-sized magnetic vortex structures. By micromagnetic simulations here, we show that in soft ferromagnetic nanodots with an adequate modulated thickness, the desired combination of chirality and polarity can be achieved just by changing the direction of the in-plane applied magnetic field. Despite the complex behavior, the vortex chirality and polarity control can be summari...

  17. Quantum switching of polarization in mesoscopic ferroelectrics

    International Nuclear Information System (INIS)

    Sa de Melo, C.A.

    1996-01-01

    A single domain of a uniaxial ferroelectric grain may be thought of as a classical permanent memory. At the mesoscopic level this system may experience considerable quantum fluctuations due to tunneling between two possible memory states, thus destroying the classical permanent memory effect. To study these quantum effects the concrete example of a mesoscopic uniaxial ferroelectric grain is discussed, where the orientation of the electric polarization determines two possible memory states. The possibility of quantum switching of the polarization in mesoscopic uniaxial ferroelectric grains is thus proposed. To determine the degree of memory loss, the tunneling rate between the two polarization states is calculated at zero temperature both in the absence and in the presence of an external static electric field. In addition, a discussion of crossover temperature between thermally activated behavior and quantum tunneling behavior is presented. And finally, environmental effects (phonons, defects, and surfaces) are also considered. copyright 1996 The American Physical Society

  18. Polar Heat Flow on Io

    Science.gov (United States)

    Veeder, G. J.; Matson, D. L.; Johnson, T. V.; Davies, A. G.; Blaney, D. L.

    2003-01-01

    Recently, Galileo spacecraft data have revealed Io's polar regions to be much warmer than previously expected. This unexpected development came from Photo-Polarimeter Radiometer (PPR) data which show that the minimum night temperatures are in the range of 90-95 K virtually everywhere on Io. The minimum night temperatures show no dependence upon latitude and, when away from the sunset terminator, they show no dependence upon time of night. This is indeed bizarre behavior for surface units which generally had been assumed to be passive with respect to Io's pervasive volcanism. Night temperatures of 90-95 K at high, polar latitudes are particularly hard to explain. Even assuming infinite thermal inertia, at these latitudes there is insufficient sunlight to support these warm night temperatures. Thus, through the process of elimination of other possibilities, we come to the conclusion that these surfaces are volcanically heated. Taking previously passive units and turning them into new sources of heat flow is a radical departure from previous thermophysical model paradigms. However, the geological interpretation is straight forward. We are simply seeing the effect of old, cool lava flows which cover most of the surface of Io but yet have some heat to radiate. Under these new constraints, we have taken on the challenge of formulating a physical model which quantitatively reproduces all of the observations of Io's thermal emission. In the following we introduce a new parametric model which suffices to identify a previously unrecognized polar component of Io's heat flow.

  19. RHIC Polarized proton operation

    International Nuclear Information System (INIS)

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D'Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R.; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.E.; Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-01-01

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP 4 . A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  20. RHIC Polarized proton operation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D' Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R,; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; J.; Severino, F.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J. Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-03-28

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP{sup 4}. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  1. The ILC polarized electron source

    CERN Document Server

    Brachmann, Axel; Garwin, Edward; Kirby, Robert; Luh Dah An; Maruyama, Takashi; Prepost, Richard; Schultz, David; Sheppard, John

    2005-01-01

    The SLC polarized electron source (PES) can meet the expected requirements of the International Linear Collider (ILC) for polarization, charge and lifetime. However, experience with newer and successful PES designs at JLAB, Mainz and elsewhere can be incorporated into a first-generation ILC source that will emphasize reliability and stability without compromising the photocathode performance. The long pulse train for the ILC may introduce new challenges for the PES, and in addition more reliable and stable operation of the PES may be achievable if appropriate R&D is carried out for higher voltage operation and for a simpler load-lock system. The outline of the R&D program currently taking shape at SLAC and elsewhere is discussed. The principal components of the proposed ILC PES, including the laser system necessary for operational tests, are described.

  2. What to eat now? Shifts in polar bear diet during the ice-free season in western Hudson Bay

    Science.gov (United States)

    Gormezano, Linda J; Rockwell, Robert F

    2013-01-01

    Under current climate trends, spring ice breakup in Hudson Bay is advancing rapidly, leaving polar bears (Ursus maritimus) less time to hunt seals during the spring when they accumulate the majority of their annual fat reserves. For this reason, foods that polar bears consume during the ice-free season may become increasingly important in alleviating nutritional stress from lost seal hunting opportunities. Defining how the terrestrial diet might have changed since the onset of rapid climate change is an important step in understanding how polar bears may be reacting to climate change. We characterized the current terrestrial diet of polar bears in western Hudson Bay by evaluating the contents of passively sampled scat and comparing it to a similar study conducted 40 years ago. While the two terrestrial diets broadly overlap, polar bears currently appear to be exploiting increasingly abundant resources such as caribou (Rangifer tarandus) and snow geese (Chen caerulescens caerulescens) and newly available resources such as eggs. This opportunistic shift is similar to the diet mixing strategy common among other Arctic predators and bear species. We discuss whether the observed diet shift is solely a response to a nutritional stress or is an expression of plastic foraging behavior. PMID:24223286

  3. Our Polar Past

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2009-01-01

    The study of polar exploration is fascinating and offers students insights into the history, culture, and politics that affect the developing sciences at the farthest ends of Earth. Therefore, the authors think there is value in incorporating polar exploration accounts within modern science classrooms, and so they conducted research to test their…

  4. Terahertz polarization imaging

    NARCIS (Netherlands)

    Van der Valk, N.C.J.; Van der Marel, W.A.M.; Planken, P.C.M.

    2005-01-01

    We present a new method to measure the polarization state of a terahertz pulse by using a modified electrooptic sampling setup. To illustrate the power of this method, we show two examples in which the knowledge of the polarization of the terahertz pulse is essential for interpreting the results:

  5. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    The acceleration of polarized proton beams in circular accelerators is complicated by the presence of numerous depolarizing spin resonances. Careful and tedious minimization of polarization loss at each of these resonances allowed acceleration of polarized proton beams up to 22 GeV. It has been the hope that Siberian Snakes, which are local spin rotators inserted into ring accelerators, would eliminate these resonances and allow acceleration of polarized beams with the same ease and efficiency that is now routine for unpolarized beams. First tests at IUCF with a full Siberian Snake showed that the spin dynamics with a Snake can be understood in detail. The author now has results of the first tests of a partial Siberian Snake at the AGS, accelerating polarized protons to an energy of about 25 GeV. These successful tests of storage and acceleration of polarized proton beams open up new possibilities such as stored polarized beams for internal target experiments and high energy polarized proton colliders

  6. Polar Science Is Cool!

    Science.gov (United States)

    Weeks, Sophie

    2012-01-01

    Children are fascinated by the fact that polar scientists do research in extremely cold and dangerous places. In the Arctic they might be viewed as lunch by a polar bear. In the Antarctic, they could lose toes and fingers to frostbite and the wind is so fast it can rip skin off. They camp on ice in continuous daylight, weeks from any form of…

  7. Precision Polarization of Neutrons

    Science.gov (United States)

    Martin, Elise; Barron-Palos, Libertad; Couture, Aaron; Crawford, Christopher; Chupp, Tim; Danagoulian, Areg; Estes, Mary; Hona, Binita; Jones, Gordon; Klein, Andi; Penttila, Seppo; Sharma, Monisha; Wilburn, Scott

    2009-05-01

    Determining polarization of a cold neutron beam to high precision is required for the next generation neutron decay correlation experiments at the SNS, such as the proposed abBA and PANDA experiments. Precision polarimetry measurements were conducted at Los Alamos National Laboratory with the goal of determining the beam polarization to the level of 10-3 or better. The cold neutrons from FP12 were polarized using optically polarized ^3He gas as a spin filter, which has a highly spin-dependent absorption cross section. A second ^ 3He spin filter was used to analyze the neutron polarization after passing through a resonant RF spin rotator. A discussion of the experiment and results will be given.

  8. Optically polarized 3He

    Science.gov (United States)

    Gentile, T. R.; Nacher, P. J.; Saam, B.; Walker, T. G.

    2018-01-01

    This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements. PMID:29503479

  9. Optically polarized 3He

    Science.gov (United States)

    Gentile, T. R.; Nacher, P. J.; Saam, B.; Walker, T. G.

    2017-10-01

    This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements.

  10. Parallel Polarization State Generation.

    Science.gov (United States)

    She, Alan; Capasso, Federico

    2016-05-17

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

  11. Leakage current behavior in lead-free ferroelectric (K,Na)NbO3-LiTaO3-LiSbO3 thin films

    Science.gov (United States)

    Abazari, M.; Safari, A.

    2010-12-01

    Conduction mechanisms in epitaxial (001)-oriented pure and 1 mol % Mn-doped (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.1,Sb0.06)O3 (KNN-LT-LS) thin films on SrTiO3 substrate were investigated. Temperature dependence of leakage current density was measured as a function of applied electric field in the range of 200-380 K. It was shown that the different transport mechanisms dominate in pure and Mn-doped thin films. In pure (KNN-LT-LS) thin films, Poole-Frenkel emission was found to be responsible for the leakage, while Schottky emission was the dominant mechanism in Mn-doped thin films at higher electric fields. This is a remarkable yet clear indication of effect of 1 mol % Mn on the resistive behavior of such thin films.

  12. Slow oscillating transcranial direct current stimulation during non-rapid eye movement sleep improves behavioral inhibition in attention-deficit/ hyperactivity disorder

    Directory of Open Access Journals (Sweden)

    Manuel Tobias Munz

    2015-08-01

    Full Text Available Background: Behavioral inhibition, which is a later-developing executive function (EF and anatomically located in prefrontal areas, is impaired in attention-deficit and hyperactivity disorder (ADHD. While optimal EFs have been shown to depend on efficient sleep in healthy subjects, the impact of sleep problems, frequently reported in ADHD, remains elusive. Findings of macroscopic sleep changes in ADHD are inconsistent, but there is emerging evidence for distinct microscopic changes with a focus on prefrontal cortical regions and non-rapid eye movement (non-REM slow-wave sleep. Recently, slow oscillations (SO during non-REM sleep were found to be less functional and, as such, may be involved in sleep-dependent memory impairments in ADHD. Objective: By augmenting slow-wave power through bilateral, slow oscillating transcranial direct current stimulation (so-tDCS, frequency = 0.75 Hz during non-REM sleep, we aimed to improve daytime behavioral inhibition in children with ADHD. Methods: 14 boys (10-14 yrs diagnosed with ADHD were included. In a randomized, double-blind, cross-over design, patients received so-tDCS either in the first or in the second experimental sleep night. Inhibition control was assessed with a visuomotor go/no-go task. Intrinsic alertness was assessed with a simple stimulus response task. To control for visuomotor performance, motor memory was assessed with a finger sequence tapping task. Results: SO-power was enhanced during early non-REM sleep, accompanied by slowed reaction times and decreased standard deviations of reaction times, in the go/no-go task after so-tDCS. In contrast, intrinsic alertness and motor memory performance were not improved by so-tDCS. Conclusion: Since behavioral inhibition but not intrinsic alertness or motor memory was improved by so-tDCS, our results suggest that lateral prefrontal slow oscillations during sleep might play a specific role for executive functioning in ADHD.

  13. On the behavior of reduced graphene oxide based electrodes coated with dispersed platinum by alternate current methods in the electrochemical degradation of reactive dyes.

    Science.gov (United States)

    Del Río, A I; García, C; Molina, J; Fernández, J; Bonastre, J; Cases, F

    2017-09-01

    The electrochemical behavior of different carbon-based electrodes with and without nanoparticles of platinum electrochemically dispersed on their surface has been studied. Among others, reduced graphene oxide based electrodes was used to determine the best conditions for the decolorization/degradation of the reactive dye C.I. Reactive Orange 4 in sulfuric medium. Firstly, the electrochemical behavior was evaluated by cyclic voltammetry. Secondly, different electrolyses were performed using two cell configurations: cell with anodic and cathodic compartments separated (divided configuration) and without any separation (undivided configuration). The best results were obtained when reduced graphene oxide based anodes were used. The degree of decolorization was monitored by spectroscopic methods and high performance liquid chromatography. It was found that all of them followed pseudo-first order kinetics. When reduced graphene oxide-based electrodes coated with dispersed platinum by alternate current methods electrodes were used, the lowest energy consumption and the higher decolorization kinetics rate were obtained. Scanning Electronic Microscopy was used to observe the morphological surface differences. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Physics with polarized electrons and targets

    International Nuclear Information System (INIS)

    Donnelly, T.W.

    1984-01-01

    With the advent of electron stretcher or storage rings electron scattering from polarized targets becomes a general new tool for nuclear structure studies. Without such facilities it is necessary to have very dense polarized targets for use with the typical (less or approximately equal 50 μA) electron beams available and very few measurements of this type have been attempted. On the other hand, with electron rings the effective circulating current can be greatly increased. In this case much thinner internal targets may be used while still maintaining the same luminosity as in external beam experiments. In ancticipation of such new experimental capabilities we have re-developed the theoretical basis for discussions of electron scattering from polarized targets using either unpolarized or polarized electron beams. This work takes the formalism of unpolarized (e,e') and extends it in a straightforward way to include general polarizations of electrons, target nuclei, recoil nuclei or any combinations of these polarizations. In the present context it is only possible to provide a brief summary of the general form of the cross section and to present a few illustrative examples of the nuclear structure information that may be extracted from such polarization measurements

  15. The interaction of approach-alcohol action tendencies, working memory capacity, and current task goals predicts the inability to regulate drinking behavior.

    Science.gov (United States)

    Sharbanee, Jason M; Stritzke, Werner G K; Wiers, Reinout W; Young, Paul; Rinck, Mike; MacLeod, Colin

    2013-09-01

    The inability to regulate alcohol consumption has been attributed to an imbalance between stimulus-driven behavioral biases, or action tendencies, and the ability to exert goal-directed control, or working memory capacity (WMC). Previous research assessing the interaction between these variables has not considered the effect of whether individuals' current goals or task demands require goal-directed control. Our aim was to examine the potential interaction of appetitive action tendencies and the ability to exert control over these action tendencies as a function of whether task demands require applying control for successful task completion. Two groups of social drinkers (n = 40 per group) who differed in their ability to regulate their alcohol consumption completed a novel variant of the Approach-Avoidance Task (AAT), which separately assessed approach and avoid trials. The approach and avoidance responses differentially require goal-directed control, depending on whether the task-relevant response is incongruent with the stimulus-driven action tendency. Results indicated that (a) group differences in AAT indices were only observed on trials that required an avoidance movement, which are trials where the task-relevant response would be incongruent with an approach action tendency, and (b) the extent of the group differences for these avoidance trials was moderated by individual differences in WMC, such that problem drinkers with lower WMC showed greater behavioral bias toward alcohol than those with higher WMC. These findings suggest that difficulties in regulating alcohol consumption arise from a complex interaction of action-tendencies, WMC, and current goals or task demands. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  16. Polarization at the SLC

    Energy Technology Data Exchange (ETDEWEB)

    Moffeit, K.C.

    1988-10-01

    The Stanford Linear collider was designed to accommodate polarized electron beams. Longitudinally polarized electrons colliding with unpolarized positrons at a center of mass energy near the Z/sup 0/ mass can be used as novel and sensitive probes of the electroweak process. A gallium arsenide based photon emission source will provide a beam of longitudinally polarized electrons of about 45 percent polarization. A system of bend magnets and a superconducting solenoid will be used to rotate the spins so that the polarization is preserved while the 1.21 GeV electrons are stored in the damping ring. Another set of bend magnets and two superconducting solenoids orient the spin vectors so that longitudinal polarization of the electrons is achieved at the collision point with the unpolarized positrons. A system to monitor the polarization based on Moller and Compton scattering will be used. Nearly all major components have been fabricated and tested. Subsystems of the source and polarimeters have been installed, and studies are in progress. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. 8 refs., 16 figs., 1 tab.

  17. Polarized H- source development at BNL

    International Nuclear Information System (INIS)

    Alessi, J.G.; Hershcovitch, A.; Kponou, A.; Niinikoski, T.; Sluyters, T.

    1986-01-01

    The AGS polarized H - source (PONI-1) now produces currents of 25-40 μA, and has operated reliably during polarized physics runs. A new polarized source, having as its goal mA's of H-vector, is now under development. An atomic hydrogen beam has been cooled to about 20 K with a forward flux of approx.10 19 atoms/s/sr. A superconducting solenoid having a calculated acceptance angle of 0.1 sr for the cold H 0 beam, is now being built. An ionizer for the resulting polarized H 0 beam based on resonant charge exchange of H 0 with D - , is being tested. 500 μA of H - have been produced by ionizing an unpolarized H 0 beam using this ionizer

  18. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    Grueebler, W.

    1984-01-01

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  19. Polarized scintillator targets

    Science.gov (United States)

    van den Brandt, B.; Bunyatova, E. I.; Hautle, P.; Konter, J. A.; Mango, S.

    2000-05-01

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as "live" polarized targets in nuclear physics experiments.

  20. Polarized scintillator targets

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, B. van den E-mail: vandenbrandt@psi.ch; Bunyatova, E.I.; Hautle, P.; Konter, J.A.; Mango, S

    2000-05-21

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as 'live' polarized targets in nuclear physics experiments.

  1. Heidelberg polarized alkali source

    International Nuclear Information System (INIS)

    Kraemer, D.; Steffens, E.; Jaensch, H.; Philipps Universitaet, Marburg, Germany)

    1984-01-01

    A new atomic beam type polarized alkali ion source has been installed at Heidelberg. In order to improve the beam polarization considerably optical pumping is applied in combination with an adiabatic medium field transition which results in beams in single hyperfine sublevels. The m state population is determined by laser-induced fluorescence spectroscopy. Highly polarized beams (P/sub s/ > 0.9, s = z, zz) with intensities of 30 to 130 μA can be extracted for Li + and Na + , respectively

  2. Experimental and theoretical studies on electropolymerization of polar amino acids on platinum electrode

    Energy Technology Data Exchange (ETDEWEB)

    Alhedabi, Taleb [Nanomedicine Lab EA4662, Bat. E, Université de Bourgogne Franche-Comté, UFR Sciences & Techniques, 16 route de Gray, 25030 Besançon Cedex (France); Department of Chemistry, College of Science, University of Thi-qar, Thi-qar (Iraq); Cattey, Hélène [Institut ICMUB - CNRS 6302, Université de Bourgogne Franche-Comté, UFR Sciences et Techniques Mirande, 9 Avenue Alain Savary, 21000 Dijon (France); Roussel, Christophe [Ecole Polytechnique Fédérale de Lausanne, Section of Chemistry and Chemical Engineering, Station 6, CH-1015 Lausanne (Switzerland); Blondeau-Patissier, Virginie [Institut FEMTO-ST, UMR CNRS 6174, Department Time-Frequency, 26, Chemin de l' épitaphe, 25030 Besançon Cedex (France); Gharbi, Tijani [Nanomedicine Lab EA4662, Bat. E, Université de Bourgogne Franche-Comté, UFR Sciences & Techniques, 16 route de Gray, 25030 Besançon Cedex (France); Herlem, Guillaume, E-mail: guillaume.herlem@univ-fcomte.fr [Nanomedicine Lab EA4662, Bat. E, Université de Bourgogne Franche-Comté, UFR Sciences & Techniques, 16 route de Gray, 25030 Besançon Cedex (France)

    2017-01-01

    The anodic oxidation of polar amino acids (L-serine, L-threonine, L-asparagine, and L-glutamine) in aqueous electrolyte on smooth platinum electrode was carried out by cyclic voltammetry coupled to electrochemical quartz crystal microbalance (EQCM). pH (zwitterion, acidic and alkaline) effects on their electrochemical behavior were examined. The maximum current values are measured for zwitterion species. In addition, the current increases with increasing of concentration and scan rate, and decreases with increasing pH. The resulting passivation was studied by spectroscopic analysis such as attenuated total reflection FT infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and mass spectroscopy (MALDI-TOF). From thin film coatings observed on the electrode surface, peptide bonds are found, and are in favor of electropolymerization of these polar amino acids into poly-L-amino acids in an irreversible way. Scanning electronic microscopy was also used to study the morphology of these electrodeposited L-amino acids. The electrodeposited poly-L-amino acids on Pt electrode were tested as bioinspired transducer for pH sensing purposes. - Highlights: • Anodic oxidation of polar amino acids with uncharged R group on platinum electrode. • Polypeptide bonds revealed by ATR-IR and XPS spectroscopies. • The film growth depends on the chemistry of the polar amino acid.

  3. Polarization measurement in the COMPASS polarized target

    CERN Document Server

    Kondo, K; Baum, G; Berglund, P; Doshita, N; Gautheron, F; Görtz, S; Hasegawa, T; Horikawa, N; Ishimoto, S; Iwata, T; Kisselev, Yu V; Koivuniemi, J H; Le Goff, J M; Magnon, A; Meyer, W; Reicherz, G; Matsuda, T

    2004-01-01

    Continuous wave nuclear magnetic resonance (NMR) is used to determine the target polarization in the COMPASS experiment. The system is made of the so-called Liverpool Q-meters, Yale-cards, and VME modules for data taking and system controlling. In 2001 the NMR coils were embedded in the target material, while in 2002 and 2003 the coils were mounted on the outer surface of the target cells to increase the packing factor of the material. Though the error of the measurement became larger with the outer coils than with the inner coils, we have performed stable measurements throughout the COMPASS run time for 3 years. The maximum polarization was +57% and -53% as the average in the target cells.

  4. Complexity of childhood sexual abuse: Predictors of current PTSD, mood disorders, substance use, and sexual risk behavior among adult men who have sex with men

    Science.gov (United States)

    Boroughs, Michael S.; Valentine, Sarah E.; Ironson, Gail H.; Shipherd, Jillian C.; Safren, Steven A.; Taylor, S. Wade; Dale, Sannisha K.; Baker, Joshua S.; Wilner, Julianne G.; O'Cleirigh, Conall

    2016-01-01

    Men who have sex with men (MSM) are the group most at risk for HIV and represent the majority of new infections in the United States. Rates of childhood sexual abuse (CSA) among MSM have been estimated as high as 46%. CSA is associated with increased risk of HIV and greater likelihood of HIV sexual risk behavior. The purpose of this study was to identify the relationships between CSA complexity indicators and mental health, substance use, sexually transmitted infections (STIs) and HIV sexual risk among MSM. MSM with CSA histories (n = 162) who were screened for an HIV-prevention efficacy trial completed comprehensive psychosocial assessments. Five indicators of complex CSA experiences were created: CSA by family member, CSA with penetration, CSA with physical injury, CSA with intense fear, and first CSA in adolescence. Adjusted regression models were used to identify relationships between CSA complexity and outcomes. Participants reporting CSA by family member were at 2.6 odds of current alcohol use disorder (OR: 2.64: CI 1.24 – 5.63), 2 times higher odds of substance use disorder (OR 2.1: CI 1.02 – 2.36), and 2.7 times higher odds of reporting an STI in the past year (OR 2.7: CI 1.04 – 7.1). CSA with penetration was associated with increased likelihood of current PTSD (OR 3.17: CI 1.56 – 6.43), recent HIV sexual risk behavior (OR 2.7: CI 1.16 – 6.36) and a greater number of casual sexual partners (p = .02). Both CSA with Physical Injury (OR 4.05: CI 1.9 – 8.7) and CSA with Intense Fear (OR 5.16: CI 2.5 – 10.7) were related to increased odds for current PTSD. First CSA in adolescence was related to increased odds of major depressive disorder. These findings suggest that CSA, with one or more complexities, creates patterns of vulnerabilities for MSM, including PTSD, substance use, and sexual risk taking and suggests the need for detailed assessment of CSA and the development of integrated HIV prevention programs that address mental health and substance

  5. Hybrid Streamers for Polar Seismic

    Science.gov (United States)

    Gifford, C. M.; Agah, A.; Tsoflias, G. P.

    2006-12-01

    We propose a new hybrid streamer seismic approach for polar regions that incorporates insertion of spiked geophones, the land streamer method of transportation, and mobile robotics. Current land streamers do not plant the geophone spike at each node location on the streamer(s) nor use robotic control. This approach combines the two methods, and is therefore termed "Hybrid Streamers". Land seismic 3D surveying is costly and time consuming due to manual handling of geophones and cables. Multiple streamers make this process simpler by allowing efficient deployment of large numbers of geophones. Hybrid streamers go further to robotically insert the geophone spike at each node location to achieve higher frequency and better resolution seismic images. For deployment and retrieval, the geophone spikes are drilled into the ground, or inserted using heat. This can be accomplished by modifying the geophone spike to be similar to a threaded screw or similar to a soldering iron for polar environments. Heat could help melt the ice during deployment, which would refreeze around the geophone for firm coupling. Heat could also be used to make polar geophone retrieval easier. By ensuring that the towing robots are robust and effective, the problem of single point of failure can be less of an issue. Polar rovers have proven useful in harsh environments, and could be utilized in polar seismic applications. Towing geophone nodes in a tethered fashion not only provides all nodes with power to operate the onboard equipment, but also gives them a medium to transfer data to the towing rover. Hybrid streamers could be used in several ways. One or more hybrid streamers could be tethered and towed by a single robot. Several robots could be used to form a single grid, working in conjunction to image larger areas in three dimensions. Such an approach could speed up entire missions and make efficient use of seismic source ignitions. The reduction of human involvement by use of mobile robots

  6. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H.B. [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  7. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca; Auken, Esben; Christiansen, Anders Vest

    2012-01-01

    Time-domain-induced polarization has significantly broadened its field of reference during the last decade, from mineral exploration to environmental geophysics, e.g., for clay and peat identification and landfill characterization. Though, insufficient modeling tools have hitherto limited the use...... of time-domaininduced polarization for wider purposes. For these reasons, a new forward code and inversion algorithm have been developed using the full-time decay of the induced polarization response, together with an accurate description of the transmitter waveform and of the receiver transfer function......%. Furthermore, the presence of low-pass filters in time-domain-induced polarization instruments affects the early times of the acquired decays (typically up to 100 ms) and has to be modeled in the forward response to avoid significant loss of resolution. The developed forward code has been implemented in a 1D...

  8. Polarized proton colliders

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    High energy polarized beam collisions will open up the unique physics opportunities of studying spin effects in hard processes. This will allow the study of the spin structure of the proton and also the verification of the many well documented expectations of spin effects in perturbative QCD and parity violation in W and Z production. Proposals for polarized proton acceleration for several high energy colliders have been developed. A partial Siberian Snake in the AGS has recently been successfully tested and full Siberian Snakes, spin rotators, and polarimeters for RHIC are being developed to make the acceleration of polarized beams to 250 GeV possible. This allows for the unique possibility of colliding two 250 GeV polarized proton beams at luminosities of up to 2 x 10 32 cm -2 s -1

  9. The impacts of surface polarity on the solubility of nanoparticle

    International Nuclear Information System (INIS)

    Zhu, Jianzhuo; Su, Jiguo; Ou, Xinwen; Li, Jingyuan

    2016-01-01

    In order to study the dependence of water solubility and hydration behavior of nanoparticles on their surface polarity, we designed polar nanoparticles with varying surface polarity by assigning atomic partial charge to the surface of C60. The water solubility of the nanoparticle is enhanced by several orders of magnitude after the introduction of surface polarity. Nevertheless, when the atomic partial charge grows beyond a certain value (q M ), the solubility continuously decreases to the level of nonpolar nanoparticle. It should be noted that such q M is comparable with atomic partial charge of a variety of functional groups. The hydration behaviors of nanoparticles were then studied to investigate the non-monotonic dependence of solubility on the surface polarity. The interaction between the polar nanoparticle and the hydration water is stronger than the nonpolar counterpart, which should facilitate the dissolution of the nanoparticles. On the other hand, the surface polarity also reduces the interaction of hydration water with the other water molecules and enhances the interaction between the nanoparticles which may hinder their dispersion. Besides, the introduction of surface polarity disturbs and even rearranges the hydration structure of nonpolar nanoparticle. Interestingly, the polar nanoparticle with less ordered hydration structure tends to have higher water solubility.

  10. Plasma polarization spectroscopy

    International Nuclear Information System (INIS)

    Iwamae, Atsushi; Horimoto, Yasuhiro; Fujimoto, Takashi; Hasegawa, Noboru; Sukegawa, Kouta; Kawachi, Tetsuya

    2005-01-01

    The electron velocity distribution function (EVDF) in plasma can be anisotropic in laser-produced plasmas. We have developed a new technique to evaluate the polarization degree of the emission lines in the extreme vacuum ultra violet wavelength region. The polarization of the emission lines and the continuums from the lithium-like nitrogen and from helium- and hydrogen-like carbon in recombining plasma is evaluated. Particle simulation in the velocity space gives the time scale for relaxation of anisotropic EVDFs. (author)

  11. Ultracold Polar Molecules

    Science.gov (United States)

    2016-04-01

    AFRL-AFOSR-UK-TR-2016-0005 Ultracold Polar Molecules Jeremy Hutson UNIVERSITY OF DURHAM Final Report 04/01/2016 DISTRIBUTION A: Distribution approved...DATES COVERED (From - To) 15-Jan-2010 to 14-Jul-2015 4. TITLE AND SUBTITLE Final Report on Grant FA8655-10-1-3033 on Ultracold Polar Molecules 5a...formation of ultracold 87RbCs molecules in their rovibrational ground state by magnetoassociation followed by STIRAP, resulting in 14 papers acknowledging

  12. Performance comparison of polarized white light emitting diodes using wire-grid polarizers with polymeric and glass substrates

    Science.gov (United States)

    Su, Jung-Chieh; Chou, Shih-Chieh

    2018-03-01

    Polarized white light emitting diodes (WLEDs) packaged with reflective metal wire-grid polarizer of polymeric and glass substrates were investigated. The performance comparison of polymeric wire-grid polarizer film (WGF) and nano wire-grid polarizer (NWGP) with glass substrate was evaluated. The transverse electric field (TE) polarization transmittance of WGF is less than that of NWGP due to its smaller grid parameters. Despite of the higher duty cycle of WGF, the angular-dependent extinction ratio (ER) of the polarized WLEDs (PWLEDs) with WGF is higher than that of with NWGP. Regarding increasing drive currents, the PWLEDs with NWGP had better color stability than that with WGF due to better substrate thermal stability. In summary, linewidth, period and substrate material are the crucial factors for the PWLED packaging using wire grid polarizer.

  13. Hsp Polarization Verification

    Science.gov (United States)

    Bless, Robert

    1991-07-01

    This proposal defines the procedure for determining the instrumental polarization of the polarimetric IDT (IDT#1, POL) on the HSP. 1 of 2 unpolarized standard stars wil be observed using various filter-polarizer combinations. These observations will permit the instrumental polarization to be calibrated. The instrumental polarization must be determined to a high precision in order to vectoriallly remove it from HSP polarization observations to determine the actual astronomical polarization. Final run of proposal will look at one of 2 possible stars previously observed to get another look at the throughput. Revision History: Mark H. Slovak 8/30/88 Translated to V2 proposal instructions (RPSS V6.2) S. Laurent 1/20/89 Updated: Sally Laurent 2/24/89, 3/20/89, 4/13/89, 5/12/89 Modified: P. Stanley 1/15/90 - change to use CTA selected targets only; Fixes for aberration problem - SALM 7/30/90; Based on SV/HSP 1386. New submission changed targets and revised scheduling strategy. Revised: 26 Aug 92 J. Dolan, L. Walter, P. Reppert want to re-run the proposal (3985) one last time to bring down errors.

  14. Production of Polarized Ions with Nearly Resonant Charge-Exchange Collisions in Plasma

    Science.gov (United States)

    Belov, A. S.

    2008-02-01

    Review of results of development of polarized ion sources with nearly resonant charge-exchange plasma ionizer is presented. Pulsed beams of polarized protons with peak intensity up to 11 mA and polarization of 80% and polarized negative hydrogen ions with peak current of 4 mA and polarization of 91% have been obtained. Polarized deuterons, negative deuterium ions and 3He++ ions can be produced by this method as well. A study of a pulsed polarized atomic hydrogen beam has been performed. It was found that intensity of the pulsed atomic hydrogen beam is limited by a beam-skimmer interference and by noncomplete cooling of hydrogen atoms.

  15. Production of Polarized Ions with Nearly Resonant Charge-Exchange Collisions in Plasma

    International Nuclear Information System (INIS)

    Belov, A. S.

    2008-01-01

    Review of results of development of polarized ion sources with nearly resonant charge-exchange plasma ionizer is presented. Pulsed beams of polarized protons with peak intensity up to 11 mA and polarization of 80% and polarized negative hydrogen ions with peak current of 4 mA and polarization of 91% have been obtained. Polarized deuterons, negative deuterium ions and 3 He ++ ions can be produced by this method as well. A study of a pulsed polarized atomic hydrogen beam has been performed. It was found that intensity of the pulsed atomic hydrogen beam is limited by a beam-skimmer interference and by noncomplete cooling of hydrogen atoms

  16. Polarized Light Microscopy

    Science.gov (United States)

    Frandsen, Athela F.

    2016-01-01

    Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

  17. Giant flexoelectric polarization in a micromachined ferroelectric diaphragm

    KAUST Repository

    Wang, Zhihong

    2012-08-14

    The coupling between dielectric polarization and strain gradient, known as flexoelectricity, becomes significantly large on the micro- and nanoscale. Here, it is shown that giant flexoelectric polarization can reverse remnant ferroelectric polarization in a bent Pb(Zr0.52Ti0.48) O3 (PZT) diaphragm fabricated by micromachining. The polarization induced by the strain gradient and the switching behaviors of the polarization in response to an external electric field are investigated by observing the electromechanical coupling of the diaphragm. The method allows determination of the absolute zero polarization state in a PZT film, which is impossible using other existing methods. Based on the observation of the absolute zero polarization state and the assumption that bending of the diaphragm is the only source of the self-polarization, the upper bound of flexoelectric coefficient of PZT film is calculated to be as large as 2.0 × 10-4 C m -1. The strain gradient induced by bending the diaphragm is measured to be on the order of 102 m-1, three orders of magnitude larger than that obtained in the bulk material. Because of this large strain gradient, the estimated giant flexoelectric polarization in the bent diaphragm is on the same order of magnitude as the normal remnant ferroelectric polarization of PZT film. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. The evolution of tensor polarization

    International Nuclear Information System (INIS)

    Huang, H.; Lee, S.Y.; Ratner, L.

    1993-01-01

    By using the equation of motion for the vector polarization, the spin transfer matrix for spin tensor polarization, the spin transfer matrix for spin tensor polarization is derived. The evolution equation for the tensor polarization is studied in the presence of an isolate spin resonance and in the presence of a spin rotor, or snake

  19. Bringing Society to a Changing Polar Ocean: Polar Interdisciplinary Coordinated Education (ICE)

    Science.gov (United States)

    Schofield, O.

    2015-12-01

    Environmental changes in the Arctic and Antarctic appear to be accelerating and scientists are trying to understand both the patterns and the impacts of change. These changes will have profound impact on humanity and create a need for public education about these critical habitats. We have focused on a two-pronged strategy to increase public awareness as well as enable educators to discuss comfortably the implications of climate change. Our first focus is on entraining public support through the development of science documentaries about the science and people who conduct it. Antarctic Edge is a feature length award-winning documentary about climate change that has been released in May 2015 and has garnered interest in movie theatres and on social media stores (NetFlix, ITunes). This broad outreach is coupled with our group's interest assisting educators formally. The majority of current polar education is focused on direct educator engagement through personal research experiences that have impact on the participating educators' classrooms. Polar Interdisciplinary Coordinated Education (ICE) proposes to improve educator and student engagement in polar sciences through exposure to scientists and polar data. Through professional development and the creation of data tools, Polar ICE will reduce the logistical costs of bringing polar science to students in grades 6-16. We will provide opportunities to: 1) build capacity of polar scientists in communicating and engaging with diverse audiences; 2) create scalable, in-person and virtual opportunities for educators and students to engage with polar scientists and their research through data visualizations, data activities, educator workshops, webinars, and student research symposia; and 3) evaluate the outcomes of Polar ICE and contribute to our understanding of science education practices. We will use a blended learning approach to promote partnerships and cross-disciplinary sharing. This combined multi-pronged approach

  20. Advancing Environmental Prediction Capabilities for the Polar Regions and Beyond during The Year of Polar Prediction

    Science.gov (United States)

    Werner, Kirstin; Goessling, Helge; Hoke, Winfried; Kirchhoff, Katharina; Jung, Thomas

    2017-04-01

    Environmental changes in polar regions open up new opportunities for economic and societal operations such as vessel traffic related to scientific, fishery and tourism activities, and in the case of the Arctic also enhanced resource development. The availability of current and accurate weather and environmental information and forecasts will therefore play an increasingly important role in aiding risk reduction and safety management around the poles. The Year of Polar Prediction (YOPP) has been established by the World Meteorological Organization's World Weather Research Programme as the key activity of the ten-year Polar Prediction Project (PPP; see more on www.polarprediction.net). YOPP is an internationally coordinated initiative to significantly advance our environmental prediction capabilities for the polar regions and beyond, supporting improved weather and climate services. Scheduled to take place from mid-2017 to mid-2019, the YOPP core phase covers an extended period of intensive observing, modelling, prediction, verification, user-engagement and education activities in the Arctic and Antarctic, on a wide range of time scales from hours to seasons. The Year of Polar Prediction will entail periods of enhanced observational and modelling campaigns in both polar regions. With the purpose to close the gaps in the conventional polar observing systems in regions where the observation network is sparse, routine observations will be enhanced during Special Observing Periods for an extended period of time (several weeks) during YOPP. This will allow carrying out subsequent forecasting system experiments aimed at optimizing observing systems in the polar regions and providing insight into the impact of better polar observations on forecast skills in lower latitudes. With various activities and the involvement of a wide range of stakeholders, YOPP will contribute to the knowledge base needed to managing the opportunities and risks that come with polar climate change.

  1. On polar daily geomagnetic variation

    Directory of Open Access Journals (Sweden)

    Paola De Michelis

    2015-11-01

    Full Text Available The aim of this work is to investigate the nature of the daily magnetic field perturbations produced by ionospheric and magnetospheric currents at high latitudes. We analyse the hourly means of the X and Y geomagnetic field components recorded by a meridian chain of permanent geomagnetic observatories in the polar region of the Northern Hemisphere during a period of four years (1995-1998 around the solar minimum. We apply a mathematical method, known as natural orthogonal component (NOC, which is capable of characterizing the dominant modes of the geomagnetic field daily variability through a set of empirical orthogonal functions (EOFs. Using the first two modes we reconstruct a two-dimensional equivalent current representation of the ionospheric electric currents, which contribute substantially to the geomagnetic daily variations. The obtained current structures resemble the equivalent current patterns of DP2 and DP1. We characterize these currents by studying their evolution with the geomagnetic activity level and by analysing their dependence on the interplanetary magnetic field. The obtained results support the idea of a coexistence of two main processes during all analysed period although one of them, the directly driven process, represents the dominant component of the geomagnetic daily variation.

  2. Hot Corrosion Behavior of Ti-48Al and Ti-48Al-2Cr Intermetallic Alloys Produced by Electric Current Activated Sintering

    Science.gov (United States)

    Garip, Y.; Ozdemir, O.

    2018-03-01

    In this study, Ti-48Al and Ti-48Al-2Cr (at. pct) intermetallic alloys were produced by electric current activated sintering (ECAS). In order to characterize the phase formation and microstructures of these alloys, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis were used. The XRD result shows that the intermetallic alloys are composed of γ-TiAl and α 2-Ti3Al phases. The microstructure is dense with a low amount of porosity. The hot corrosion behavior of intermetallic alloys was carried out in a salt mixture of 25 wt pct K2SO4 and 75 wt pct Na2SO4 at 700 °C for 180 hours. The morphology of corroded surfaces was observed by SEM-EDS and XRD. Corrosion phases were identified as TiO2 and Al2O3. Well-adhering oxide scale was detected on the corroded sample surface at the end of 180 hours, and no spallation was observed. In addition, a parabolic curve was obtained at the weight change rate vs time.

  3. Transcranial direct current stimulation (tDCS in behavioral and food addiction: A systematic review of efficacy, technical and methodological issues

    Directory of Open Access Journals (Sweden)

    Anne eSauvaget

    2015-10-01

    Full Text Available Objectives.Behavioral addictions (BA are complex disorders for which pharmacological and psychotherapeutic treatments have shown their limits. Non-invasive brain stimulation, among which transcranial direct current stimulation (tDCS, has opened up new perspectives in addiction treatment. The purpose of this work is to conduct a critical and systematic review of tDCS efficacy, and of technical and methodological considerations in the field of BA.Methods.A bibliographic search has been conducted on the Medline and ScienceDirect databases until December 2014, based on the following selection criteria: clinical studies on tDCS and BA (namely eating disorders, compulsive buying, Internet addiction, pathological gambling, sexual addiction, sports addiction, video games addiction. Study selection, data analysis and reporting were conducted according to the PRISMA guidelines.Results.Out of 402 potential articles, seven studies were selected. So far focusing essentially on abnormal eating, these studies suggest that tDCS (right prefrontal anode / left prefrontal cathode reduces food craving induced by visual stimuli.ConclusionsDespite methodological and technical differences between studies, the results are promising. So far, only few studies of tDCS in BA have been conducted. New research is recommended on the use of tDCS in BA, other than eating disorders.

  4. Effects of anodal transcranial direct current stimulation (tDCS) on behavioral and spatial memory during the early stage of traumatic brain injury in the rats.

    Science.gov (United States)

    Yoon, Kyung Jae; Lee, Yong-Taek; Chae, Seoung Wan; Park, Chae Ri; Kim, Dae Yul

    2016-03-15

    Transcranial direct current stimulation (tDCS) is a noninvasive technique to modulate the neural membrane potential. Its effects in the early stage of traumatic brain injury (TBI) have rarely been investigated. This study assessed the effects of anodal tDCS on behavioral and spatial memory in a rat model of traumatic brain injury. Thirty six rats underwent lateral fluid percussion and were then randomly assigned to one of three groups: control (n=12), five-day tDCS over peri-lesional cortex at one (1W, n=12), or two (2W, n=12) weeks post-injury. The Barnes maze (BM) and Rotarod (RR) tests were evaluated in a blind manner on day 1, week 3 and week 5 post-injury. After three weeks, both the 1W and 2W groups showed significant improvements in the BM ratio (Pearly phase after TBI when it is delivered two weeks post-injury. Earlier stimulation (one week post-injury) improves spatial memory only. However, the beneficial effects did not persist after cessation of the anodal stimulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Polar low monitoring

    Science.gov (United States)

    Bobylev, Leonid; Zabolotskikh, Elizaveta; Mitnik, Leonid

    2010-05-01

    Polar lows are intense mesoscale atmospheric low pressure weather systems, developing poleward of the main baroclinic zone and associated with high surface wind speeds. Small size and short lifetime, sparse in-situ observations in the regions of their development complicate polar low study. Our knowledge of polar lows and mesocyclones has come almost entirely during the period of satellite remote sensing since, by virtue of their small horizontal scale, it was rarely possible to analyse these lows on conventional weather charts using only the data from the synoptic observing network. However, the effects of intense polar lows have been felt by coastal communities and seafarers since the earliest times. These weather systems are thought to be responsible for the loss of many small vessels over the centuries, although the nature of the storms was not understood and their arrival could not be predicted. The actuality of the polar low research is stipulated by their high destructive power: they are a threat to such businesses as oil and gas exploration, fisheries and shipping. They could worsen because of global warming: a shrinking of sea ice around the North Pole, which thawed to its record minimum in the summer of 2007, is likely to give rise to more powerful storms that form only over open water and can cause hurricane-strength winds. Therefore, study of polar lows, their timely detection, tracking and forecasting represents a challenge for today meteorology. Satellite passive microwave data, starting from Special Sensor Microwave Imager (SSM/I) onboard Defense Meteorological Satellite Program (DMSP) satellite, remain invaluable source of regularly available remotely sensed data to study polar lows. The sounding in this spectral range has several advantages in comparison with observations in visible and infrared ranges and Synthetic Aperture Radar (SAR) data: independence on day time and clouds, regularity and high temporal resolution in Polar Regions. Satellite

  6. Quantization of interface currents

    Energy Technology Data Exchange (ETDEWEB)

    Kotani, Motoko [AIMR, Tohoku University, Sendai (Japan); Schulz-Baldes, Hermann [Department Mathematik, Universität Erlangen-Nürnberg, Erlangen (Germany); Villegas-Blas, Carlos [Instituto de Matematicas, Cuernavaca, UNAM, Cuernavaca (Mexico)

    2014-12-15

    At the interface of two two-dimensional quantum systems, there may exist interface currents similar to edge currents in quantum Hall systems. It is proved that these interface currents are macroscopically quantized by an integer that is given by the difference of the Chern numbers of the two systems. It is also argued that at the interface between two time-reversal invariant systems with half-integer spin, one of which is trivial and the other non-trivial, there are dissipationless spin-polarized interface currents.

  7. Far-from-Equilibrium Quantum Magnetism with Ultracold Polar Molecules

    Science.gov (United States)

    Hazzard, Kaden R. A.; Manmana, Salvatore R.; Foss-Feig, Michael; Rey, Ana Maria

    2013-02-01

    Recent theory has indicated how to emulate tunable models of quantum magnetism with ultracold polar molecules. Here we show that present molecule optical lattice experiments can accomplish three crucial goals for quantum emulation, despite currently being well below unit filling and not quantum degenerate. The first is to verify and benchmark the models proposed to describe these systems. The second is to prepare correlated and possibly useful states in well-understood regimes. The third is to explore many-body physics inaccessible to existing theoretical techniques. Our proposal relies on a nonequilibrium protocol that can be viewed either as Ramsey spectroscopy or an interaction quench. The proposal uses only routine experimental tools available in any ultracold molecule experiment. To obtain a global understanding of the behavior, we treat short times pertubatively, develop analytic techniques to treat the Ising interaction limit, and apply a time-dependent density matrix renormalization group to disordered systems with long range interactions.

  8. Polarized protons at RHIC

    International Nuclear Information System (INIS)

    Tannenbaum, M.J.

    1990-12-01

    The Physics case is presented for the use of polarized protons at RHIC for one or two months each year. This would provide a facility with polarizations of approx-gt 50% high luminosity ∼2.0 x 10 32 cm -2 s -1 , the possibility of both longitudinal and transverse polarization at the interaction regions, and frequent polarization reversal for control of systematic errors. The annual integrated luminosity for such running (∼10 6 sec per year) would be ∫ Ldt = 2 x 10 38 cm -2 -- roughly 20 times the total luminosity integrated in ∼ 10 years of operation of the CERN Collider (∼10 inverse picobarns, 10 37 cm -2 ). This facility would be unique in the ability to perform parity-violating measurements and polarization test of QCD. Also, the existence of p-p collisions in a new energy range would permit the study of ''classical'' reactions like the total cross section and elastic scattering, etc., and serve as a complement to measurements from p-bar p colliders. 11 refs

  9. Electrical polarization of lead bromide crystals. II

    NARCIS (Netherlands)

    Schoonman, J.; Dijkman, F.G.

    Electrical currents are measured as a function of time after application of a dc voltage on a cell arragement +C/PbBr2/C-. The presence of nonlinear polarization phenomena has been established from a test of Ohm's law, the superposition principle, and from initial and steady-state conductivities

  10. In-line Fiber Polarizer

    OpenAIRE

    Perumalsamy, Priya

    1998-01-01

    Polarizers and polarization devices are important components in fiber optic communication and sensor systems. There is a growing need for efficient low loss components that are compatible with optical fibers. An all fiber in-line polarizer is a more desirable alternative that could be placed at appropriate intervals along communication links. An in-line fiber polarizer was fabricated and tested. The in-line fiber polarizer operates by coupling optical energy propagatin...

  11. The TRIUMF optically-pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Levy, C.D.P.; Jayamanna, K.; McDonald, M.; Schmor, P.W.; Van Oers, W.T.H.; Welz, J.; Wight, G.W.; Dutto, G.; Zelenski, A.N.; Sakae, T.

    1995-09-01

    The TRIUMF dc optically-pumped polarized H - ion source (OPPIS) produces 200 μA dc H - current at 85% polarization within a normalized emittance (90%) of 0.8 π mm mrad, for operations at the TRIUMF cyclotron. As a result of development of the ECR primary proton source, 1.6 mA dc polarized H - current is produced within a normalized emittance of 2 π mm mrad, suitable for high energy accelerators. The OPPIS has also been developed for use in a parity non-conservation experiment which has very severe limits on permissible helicity-correlated changes in beam current and energy. (author)

  12. The TRIUMF optically-pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Levy, C.D.P.; Jayamanna, K.; McDonald, M.

    1995-09-01

    The TRIUMF dc optically-pumped polarized H - ion source (OPPIS) produces 200 microA dc H - current at 85% polarization within a normalized emittance (90%) of 0.8 π mm mrad, for operations at the TRIUMF cyclotron. As a result of development of the ECR primary proton source, 1.6 mA dc polarized H - current is produced within a normalized emittance of 2 π mm mrad, suitable for high energy accelerators. The OPPIS has also been developed for use in a parity non-conservation experiment which has very severe limits on permissible helicity-correlated changes in beam current and energy

  13. Study of polarization and relaxation phenomena of polyblend films ...

    Indian Academy of Sciences (India)

    Thermally stimulated discharge current (TSDC) studies were carried out on pure poly(methyl methacrylate), poly(vinyl chloride) and polyblends (of various weight ratios, 100:0, 90:10, 80:20 and 70:30) as a function of polarizing fields at constant temperature, to study the polarization and relaxation phenomena in them.

  14. Study of polarization and relaxation phenomena of polyblend films ...

    Indian Academy of Sciences (India)

    Abstract. Thermally stimulated discharge current (TSDC) studies were carried out on pure poly(methyl methacry- late), poly(vinyl chloride) and polyblends (of various weight ratios, 100:0, 90:10, 80:20 and 70:30) as a function of polarizing fields at constant temperature, to study the polarization and relaxation phenomena in ...

  15. Polarized Raman microspectroscopy on intact human hair.

    Science.gov (United States)

    Ackermann, Katrin R; Koster, Joachim; Schlücker, Sebastian

    2008-10-01

    Polarization-resolved Raman microspectroscopy with near-infrared laser excitation was applied to intact human hair in order to non-invasively investigate the conformation and orientation of the polypeptide chains. By varying the orientation of the hair shaft relative to the polarization directions of the laser/analyzer, a set of four polarized Raman spectra is obtained; this allows to simultaneously determine both the secondary structure of hair proteins and the orientation of the polypeptide strands relative to the axis of the hair shaft. For the amide I band, results from a quantitative analysis of the polarized Raman spectra are compared with theoretically expected values for fibers with uniaxial symmetry. Based on the polarization behavior of the amide I band and further vibrational bands, a partial ordering of alpha-helical polypeptide strands parallel to the hair shaft can be concluded. We suggest that this microspectroscopic approach may be used for human hair diagnostics by detecting structural or orientational alterations of keratins.

  16. Magnetic imaging with polarized soft x-rays

    Science.gov (United States)

    Fischer, Peter

    2017-08-01

    Properties, behavior, and functionalities of magnetic materials are largely determined by microscopic spin textures, particularly their formation into domains, their coupling mechanisms and their dynamic behavior. Advanced characterization tools are prerequisite to fundamentally understand magnetic materials and control spins for novel magnetic applications. Magnetic microscopies allow us to image directly the static and dynamic features of the relevant microscopic magnetization structures in advanced magnetic materials and thus provide detailed and direct insight into underlying physical phenomena. A large variety of magnetic imaging techniques has become available with particular strengths but also certain limitations. Essential features of magnetic microscopies are a high spatial resolution down into the nanometer regime, as this is the fundamental length scale of magnetic exchange interaction and the ultimate length scale in advanced magnetic technologies; magnetic and elemental sensitivity with quantitative capabilities, as the properties of advanced magnetic materials can be tailored by combining various magnetic elements and their magnetic moments; high temporal resolution from the ns to the fs regime to understand the associated spin dynamic processes and the functionality in magnetic devices; tomographic capabilities with nm resolution as new directions in nanoscience and technologies are moving into 3 dim arrangements of spin structures; and interfacial sensitivity as novel ways to control spins harness either the coupling across interfaces in multilayered structures or utilize non-collinear spin arrangements, which often occur from symmetry breaking at surfaces and interfaces. The unique properties of polarized soft x-rays, their abundancy and specific interaction with magnetic materials in form of dichroism effects have triggered the development of various magnetic x-ray imaging techniques. This review will provide an overview of the current state

  17. Polarized seismic and solitary waves run-up at the sea bed

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, L. C.C.; Zainal, A. A.; Faisal, S. Y. [Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia); Universiti Teknologi Malaysia, 81310 Johor Bahru (Malaysia)

    2012-09-26

    The polarization effects in hydrodynamics are studied. Hydrodynamic equation for the nonlinear wave is used along with the polarized solitary waves and seismic waves act as initial waves. The model is then solved by Fourier spectral and Runge-Kutta 4 methods, and the surface plot is drawn. The output demonstrates the inundation behaviors. Consequently, the polarized seismic waves along with the polarized solitary waves tend to generate dissimilar inundation which is more disastrous.

  18. Political Competition and Polarization

    DEFF Research Database (Denmark)

    Schultz, Christian

    This paper considers political competition and the consequences of political polarization when parties are better informed about how the economy functions than voters are. Specifically, parties know the cost producing a public good, voters do not. An incumbent's choice of policy acts like a signa...... for costs before an upcoming election. It is shown that the more polarized the political parties the more distorted the incumbent's policy choice.......This paper considers political competition and the consequences of political polarization when parties are better informed about how the economy functions than voters are. Specifically, parties know the cost producing a public good, voters do not. An incumbent's choice of policy acts like a signal...

  19. Physics of polarized targets

    CERN Document Server

    Niinikoski, Tapio

    2014-01-01

    For developing, building and operating solid polarized targets we need to understand several fields of physics that have seen sub stantial advances during the last 50 years. W e shall briefly review a selection of those that are important today. These are: 1) quantum statistical methods to describe saturation and relaxation in magnetic resonance; 2) equal spin temperature model for dy namic nuclear polarization; 3 ) weak saturation during NMR polarization measurement; 4 ) refrigeration using the quantum fluid properties of helium isotopes. These, combined with superconducting magnet technologies, permit today to reach nearly complete pola rization of almost any nuclear spins. Targets can be operated in frozen spin mode in rather low and inhomogeneous field of any orientation, and in DNP mode in beams of high intensity. Beyond such experiments of nuclear and particle physics, applications a re also emerging in macromolecular chemistry and in magnetic resonance imaging. This talk is a tribute to Michel Borghini...

  20. Polarized source upgrading

    International Nuclear Information System (INIS)

    Clegg, T.B.; Rummel, R.L.; Carter, E.P.; Westerfeldt, C.R.; Lovette, A.W.; Edwards, S.E.

    1985-01-01

    The decision was made this past year to move the Lamb-shift polarized ion source which was first installed in the laboratory in 1970. The motivation was the need to improve the flexibility of spin-axis orientation by installing the ion source with a new Wien-filter spin precessor which is capable of rotating physically about the beam axis. The move of the polarized source was accomplished in approximately two months, with the accelerator being turned off for experiments during approximately four weeks of this time. The occasion of the move provided the opportunity to rewire completely the entire polarized ion source frame and to rebuild approximately half of the electronic chassis on the source. The result is an ion source which is now logically wired and carefully documented. Beams obtained from the source are much more stable than those previously available

  1. A lunar polar expedition

    Science.gov (United States)

    Dowling, Richard; Staehle, Robert L.; Svitek, Tomas

    1992-09-01

    Advanced exploration and development in harsh environments require mastery of basic human survival skill. Expeditions into the lethal climates of Earth's polar regions offer useful lessons for tommorrow's lunar pioneers. In Arctic and Antarctic exploration, 'wintering over' was a crucial milestone. The ability to establish a supply base and survive months of polar cold and darkness made extensive travel and exploration possible. Because of the possibility of near-constant solar illumination, the lunar polar regions, unlike Earth's may offer the most hospitable site for habitation. The World Space Foundation is examining a scenario for establishing a five-person expeditionary team on the lunar north pole for one year. This paper is a status report on a point design addressing site selection, transportation, power, and life support requirements.

  2. Polarization vision in cuttlefish in a concealed communication channel?

    Science.gov (United States)

    Shashar; Rutledge; Cronin

    1996-01-01

    Polarization sensitivity is well documented in marine animals, but its function is not yet well understood. Of the cephalopods, squid and octopus are known to be sensitive to the orientation of polarization of incoming light. This sensitivity arises from the orthogonal orientation of neighboring photoreceptors. Electron microscopical examination of the retina of the cuttlefish Sepia officinalis L. revealed the same orthogonal structure, suggesting that cuttlefish are also sensitive to linearly polarized light. Viewing cuttlefish through an imaging polarized light analyzer revealed a prominent polarization pattern on the arms, around the eyes and on the forehead of the animals. The polarization pattern disappeared when individuals lay camouflaged on the bottom and also during extreme aggression display, attacks on prey, copulation and egg-laying behavior in females. In behavioral experiments, the responses of cuttlefish to their images reflected from a mirror changed when the polarization patterns of the reflected images were distorted. These results suggest that cuttlefish use polarization vision and display for intraspecific recognition and communication.

  3. Dark Polar Dunes

    Science.gov (United States)

    2005-01-01

    20 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, acquired during northern summer in December 2004, shows dark, windblown sand dunes in the north polar region of Mars. A vast sea of sand dunes nearly surrounds the north polar cap. These landforms are located near 80.3oN, 144.1oW. Light-toned features in the image are exposures of the substrate that underlies the dune field. The image covers an area about 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  4. Imaging with Polarized Neutrons

    Directory of Open Access Journals (Sweden)

    Nikolay Kardjilov

    2018-01-01

    Full Text Available Owing to their zero charge, neutrons are able to pass through thick layers of matter (typically several centimeters while being sensitive to magnetic fields due to their intrinsic magnetic moment. Therefore, in addition to the conventional attenuation contrast image, the magnetic field inside and around a sample can be visualized by detecting changes of polarization in a transmitted beam. The method is based on the spatially resolved measurement of the cumulative precession angles of a collimated, polarized, monochromatic neutron beam that traverses a magnetic field or sample.

  5. The polar mesosphere

    International Nuclear Information System (INIS)

    Morris, Ray; Murphy, Damian

    2008-01-01

    The mesosphere region, which lies at the edge of space, contains the coldest layer of the Earth's atmosphere, with summer temperatures as low as minus 130 °C. In this extreme environment ice aerosol layers have appeared since the dawn of industrialization—whose existence may arguably be linked to human influence—on yet another layer of the Earth's fragile atmosphere. Ground-based and space-based experiments conducted in the Arctic and Antarctic during the International Polar Year (IPY) aim to address limitations in our knowledge and to advance our understanding of thermal and dynamical processes at play in the polar mesosphere

  6. Internal polarized targets

    Energy Technology Data Exchange (ETDEWEB)

    Kinney, E.R.; Coulter, K.; Gilman, R.; Holt, R.J.; Kowalczyk, R.S.; Napolitano, J.; Potterveld, D.H.; Young, L. (Argonne National Lab., IL (USA)); Mishnev, S.I.; Nikolenko, D.M.; Popov, S.G.; Rachek, I.A.; Temnykh, A.B.; Toporkov, D.K.; Tsentalovich, E.P.; Wojtsekhowski, B.B. (AN SSSR, Novosibirsk (USSR). Inst. Yadernoj Fiziki)

    1989-01-01

    Internal polarized targets offer a number of advantages over external targets. After a brief review of the basic motivation and principles behind internal polarized targets, the technical aspects of the atomic storage cell will be discussed in particular. Sources of depolarization and the means by which their effects can be ameliorated will be described, especially depolarization by the intense magnetic fields arising from the circulating particle beam. The experience of the Argonne Novosibirsk collaboration with the use of a storage cell in a 2 GeV electron storage ring will be the focus of this technical discussion. 17 refs., 11 figs.

  7. Bias polarity-sensitive electrical failure characteristics of ZnSe nanowire in metal–semiconductor–metal nanostructure

    Directory of Open Access Journals (Sweden)

    Yu Tan

    2014-04-01

    Full Text Available The effect of bias polarity on the electrical breakdown behavior of the single ZnSe nanowire (NW in the metal–semiconductor–metal (M–S–M nanostructure under high current density and high bias conditions has been studied in the present paper. The experimental results show that the failure of the ZnSe NW in M–S–M nanostructure was sensitive to bias polarity since the NW commonly collapsed at the negatively biased Au metal electrode due to high Joule heat produced in NW at the reversely biased Schottky barrier. Thus, the electrical breakdown behavior of the ZnSe NW was highly dominated by the cathode-controlled mode due to the high resistance of the depletion region of ZnSe NW at the reversely biased Schottky contact.

  8. Polonium-210 and lead-210 in the Southern Polar Ocean: Naturally occurring tracers of biological and hydrographical processes in the surface waters of the Antarctic Circumpolar Current and the Weddell Sea

    International Nuclear Information System (INIS)

    Friedrich, J.

    1997-01-01

    In this thesis the distribution of 210 Po and 210 Pb in the upper 600 m of the Antarctic Circumpolar Current and the Weddell Sea was investigated along north-south transects in austral spring and autumn. 210 Po and 210 Pb can serve as sensitive tracers for the special hydrographic conditions of the Antarctic Circumpolar Current and the Weddell Sea as well as for biological processes during phytoplankton blooms. The 210 Po/ 210 Pb disequilibrium was used as a tracer for particle export. This tracer integrates export on a timescale of 276 days because of the 138 day half-life of 210 Po and complements the 234 Th/ 238 U disequilibrium as another tracer for plankton production and export on a shorter timescale of several weeks. (orig.) [de

  9. Quench behavior of Sr{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2}/Ag tapes with AC and DC transport currents at different temperature

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qi [Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Institute of Science, Information Engineering University, Zhengzhou 450001 (China); Zhang, Guomin, E-mail: gmzhang@mail.iee.ac.cn [Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Hua [Institute of Science, Information Engineering University, Zhengzhou 450001 (China); Li, Zhenming; Liu, Wei [China Electric Power Research Institute, Beijing 100192 (China); Jing, Liwei [Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Yu, Hui; Liu, Guole [Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China)

    2016-09-15

    Highlights: • Quench behavior of Sr{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2}/ Ag tape with AC transport current was reported for the first time. • The measurement are performed as a function of different temperature (20 K–30 K), transport current (AC and DC) and operating frequency (50 Hz–250 Hz). • The study is concentrated on the research of quench development, and the discussions of NZPV and MQE values. - Abstract: In applications, superconducting wires may carry AC or DC transport current. Thus, it is important to understand the behavior of normal zone propagation in conductors and magnets under different current conditions in order to develop an effective quench protection system. In this paper, quench behavior of Ag sheathed Sr{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2} (Sr-122 in the family of iron-based superconductor) tapes with AC and DC transport current is reported. The measurements are performed as a function of different temperature (20 K–30 K), varying transport current and operating frequency (50 Hz–250 Hz). The focus of the research is the minimum quench energy (MQE), the normal zone propagation velocity (NZPV) and the comparison of the related results with AC and DC transport current.

  10. A variable partially polarizing beam splitter

    Science.gov (United States)

    Flórez, Jefferson; Carlson, Nathan J.; Nacke, Codey H.; Giner, Lambert; Lundeen, Jeff S.

    2018-02-01

    We present designs for variably polarizing beam splitters. These are beam splitters allowing the complete and independent control of the horizontal and vertical polarization splitting ratios. They have quantum optics and quantum information applications, such as quantum logic gates for quantum computing and non-local measurements for quantum state estimation. At the heart of each design is an interferometer. We experimentally demonstrate one particular implementation, a displaced Sagnac interferometer configuration, that provides an inherent instability to air currents and vibrations. Furthermore, this design does not require any custom-made optics but only common components which can be easily found in an optics laboratory.

  11. Polarized electron sources for linear colliders

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Ecklund, S.D.; Miller, R.H.; Schultz, D.C.; Sheppard, J.C.

    1992-07-01

    Linear colliders require high peak current beams with low duty factors. Several methods to produce polarized e - beams for accelerators have been developed. The SLC, the first linear collider, utilizes a photocathode gun with a GaAs cathode. Although photocathode sources are probably the only practical alternative for the next generation of linear colliders, several problems remain to be solved, including high voltage breakdown which poisons the cathode, charge limitations that are associated with the condition of the semiconductor cathode, and a relatively low polarization of ≤5O%. Methods to solve or at least greatly reduce the impact of each of these problems are at hand

  12. Polarization Measurements on SUMI's TVLS Gratings

    Science.gov (United States)

    Kobayashi, K.; West, E. A.; Davis, J. M.; Gary, G. A.

    2007-01-01

    We present measurements of toroidal variable-line-space (TVLS) gratings for the Solar Ultraviolet Magnetograph Investigation (SUMI), currently being developed at the National Space Science and Technology Center (NSSTC). SUMI is a spectro-polarimeter designed to measure magnetic fields in the solar chromosphere by observing two UV emission lines sensitive to magnetic fields, the CIY line at 155nm and the MgII line at 280nm. The instrument uses a pair of TVLS gratings, to observe both linear polarizations simultaneously. Efficiency measurements were done on bare aluminum gratings and aluminum/MgF2 coated gratings, at both linear polarizations.

  13. Polarization Measurements on SUMI's TVLS Gratings

    Science.gov (United States)

    Kobayashi, K.; West, E. A.; Davis, J. M.; Gary, G. A.

    2007-01-01

    We present measurements of toroidal variable-line-space (TVLS) gratings for the Solar Ultraviolet Magnetograph Investigation (SUMI), currently being developed an the National Space Science and Technology Center (NSSTC). SUMI zs a spectro-polarimeter designed no measure magnetic fields in the solar chromosphere by observing two UV emission lines sensitive to magnetic fields, the C-IV line at 155nm and the Mg-II line at 280nm. The instrument uses a pair of TVLS gratings, to observe both linear polarizations simultaneously. Efficiency measurements were done on bare aluminum gratings and MgF2 coated gratings, at both linear polarizations.

  14. The physics of polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    This course is intended to give a description of the basic physical concepts which underlie the study and the interpretation of polarization phenomena. Apart from a brief historical introduction (Sect. 1), the course is organized in three parts. A first part (Sects. 2 - 6) covers the most relevant facts about the polarization phenomena that are typically encountered in laboratory applications and in everyday life. In Sect. 2, the modern description of polarization in terms of the Stokes parameters is recalled, whereas Sect. 3 is devoted to introduce the basic tools of laboratory polarimetry, such as the Jones calculus and the Mueller matrices. The polarization phenomena which are met in the reflection and refraction of a beam of radiation at the separation surface between two dielectrics, or between a dielectric and a metal, are recalled in Sect. 4. Finally, Sect. 5 gives an introduction to the phenomena of dichroism and of anomalous dispersion and Sect. 6 summarizes the polarization phenomena that are commonly encountered in everyday life. The second part of this course (Sects. 7-14) deals with the description, within the formalism of classical physics, of the spectro-polarimetric properties of the radiation emitted by accelerated charges. Such properties are derived by taking as starting point the Liénard and Wiechert equations that are recalled and discussed in Sect. 7 both in the general case and in the non-relativistic approximation. The results are developed to find the percentage polarization, the radiation diagram, the cross-section and the spectral characteristics of the radiation emitted in different phenomena particularly relevant from the astrophysical point of view. The emission of a linear antenna is derived in Sect. 8. The other Sections are devoted to Thomson scattering (Sect. 9), Rayleigh scattering (Sect. 10), Mie scattering (Sect. 11), bremsstrahlung radiation (Sect. 12), cyclotron radiation (Sect. 13), and synchrotron radiation (Sect. 14

  15. The Energetic Value of Land-Based Foods in Western Hudson Bay and Their Potential to Alleviate Energy Deficits of Starving Adult Male Polar Bears.

    Science.gov (United States)

    Gormezano, Linda J; Rockwell, Robert F

    2015-01-01

    Climate change is predicted to expand the ice-free season in western Hudson Bay and when it grows to 180 days, 28-48% of adult male polar bears are projected to starve unless nutritional deficits can be offset by foods consumed on land. We updated a dynamic energy budget model developed by Molnar et al. to allow influx of additional energy from novel terrestrial foods (lesser snow geese, eggs, caribou) that polar bears currently consume as part of a mixed diet while on land. We calculated the units of each prey, alone and in combination, needed to alleviate these lethal energy deficits under conditions of resting or limited movement (2 km d-1) prior to starvation. We further considered the total energy available from each sex and age class of each animal prey over the period they would overlap land-bound polar bears and calculated the maximum number of starving adult males that could be sustained on each food during the ice-free season. Our results suggest that the net energy from land-based food, after subtracting costs of limited movement to obtain it, could eliminate all projected nutritional deficits of starving adult male polar bears and likely other demographic groups as well. The hunting tactics employed, success rates as well as behavior and abundance of each prey will determine the realized energetic values for individual polar bears. Although climate change may cause a phenological mismatch between polar bears and their historical ice-based prey, it may simultaneously yield a new match with certain land-based foods. If polar bears can transition their foraging behavior to effectively exploit these resources, predictions for starvation-related mortality may be overestimated for western Hudson Bay. We also discuss potential complications with stable-carbon isotope studies to evaluate utilization of land-based foods by polar bears including metabolic effects of capture-related stress and consuming a mixed diet.

  16. The Energetic Value of Land-Based Foods in Western Hudson Bay and Their Potential to Alleviate Energy Deficits of Starving Adult Male Polar Bears.

    Directory of Open Access Journals (Sweden)

    Linda J Gormezano

    Full Text Available Climate change is predicted to expand the ice-free season in western Hudson Bay and when it grows to 180 days, 28-48% of adult male polar bears are projected to starve unless nutritional deficits can be offset by foods consumed on land. We updated a dynamic energy budget model developed by Molnar et al. to allow influx of additional energy from novel terrestrial foods (lesser snow geese, eggs, caribou that polar bears currently consume as part of a mixed diet while on land. We calculated the units of each prey, alone and in combination, needed to alleviate these lethal energy deficits under conditions of resting or limited movement (2 km d-1 prior to starvation. We further considered the total energy available from each sex and age class of each animal prey over the period they would overlap land-bound polar bears and calculated the maximum number of starving adult males that could be sustained on each food during the ice-free season. Our results suggest that the net energy from land-based food, after subtracting costs of limited movement to obtain it, could eliminate all projected nutritional deficits of starving adult male polar bears and likely other demographic groups as well. The hunting tactics employed, success rates as well as behavior and abundance of each prey will determine the realized energetic values for individual polar bears. Although climate change may cause a phenological mismatch between polar bears and their historical ice-based prey, it may simultaneously yield a new match with certain land-based foods. If polar bears can transition their foraging behavior to effectively exploit these resources, predictions for starvation-related mortality may be overestimated for western Hudson Bay. We also discuss potential complications with stable-carbon isotope studies to evaluate utilization of land-based foods by polar bears including metabolic effects of capture-related stress and consuming a mixed diet.

  17. Proceedings of the workshop on polarized targets in storage rings

    International Nuclear Information System (INIS)

    Holt, R.J.

    1984-08-01

    Polarization phenomena have played an increasingly important part in the study of nuclei and nucleons in recent years. Polarization studies have been hampered by the relatively few and rather fragile polarized targets which are presently available. The concept of polarized gas targets in storage rings opens a much wider range of possibilities than is available in the external target geometry. This novel method will represent a considerable advance in nuclear physics and will continue to receive much attention in plans for future facilities. An internal, polarized-target station is being planned for the cooler ring at the Indiana University Cyclotron Facility. Internal targets are compatible with recent designs of electron accelerators proposed by the Massachusetts Institute of Technology and the Southeastern Universities Research Association. The key to nuclear-science programs based on internal targets pivots on recent developments in polarized atomic beam methods, which include the more recent laser-driven polarized targets. The workshop drew together a unique group of physicists in the fields of high-energy, nuclear and atomic physics. The meeting was organized in a manner that stimulated discussion among the 58 participants and focused on developments in polarized target technology and the underlying atomic physics. An impressive array of future possibilities for polarized targets as well as current developments in polarized target technology were discussed at the workshop. Abstracts of individual items from the workshop were prepared separately for the data base

  18. Proceedings of the workshop on polarized targets in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Holt, R.J. (ed.)

    1984-08-01

    Polarization phenomena have played an increasingly important part in the study of nuclei and nucleons in recent years. Polarization studies have been hampered by the relatively few and rather fragile polarized targets which are presently available. The concept of polarized gas targets in storage rings opens a much wider range of possibilities than is available in the external target geometry. This novel method will represent a considerable advance in nuclear physics and will continue to receive much attention in plans for future facilities. An internal, polarized-target station is being planned for the cooler ring at the Indiana University Cyclotron Facility. Internal targets are compatible with recent designs of electron accelerators proposed by the Massachusetts Institute of Technology and the Southeastern Universities Research Association. The key to nuclear-science programs based on internal targets pivots on recent developments in polarized atomic beam methods, which include the more recent laser-driven polarized targets. The workshop drew together a unique group of physicists in the fields of high-energy, nuclear and atomic physics. The meeting was organized in a manner that stimulated discussion among the 58 participants and focused on developments in polarized target technology and the underlying atomic physics. An impressive array of future possibilities for polarized targets as well as current developments in polarized target technology were discussed at the workshop. Abstracts of individual items from the workshop were prepared separately for the data base.

  19. Polarization transfer in weak pion production off the nucleon

    Science.gov (United States)

    Graczyk, Krzysztof M.; Kowal, Beata E.

    2018-01-01

    Polarization transfer (PT) observables in the single pion production induced by the charged current interaction of the neutrino with the nucleon are examined. The polarization components of the final nucleon and the charged lepton are calculated within two models for the pion production. The predictions are made for neutrino energy of the order of 1 GeV as well as for the T2K energy distribution. It is demonstrated that the PT observables, the degree of polarization and the polarization components of outgoing fermions, are sensitive to assumptions about the nonresonant background model. In particular it is shown that the normal components of the polarization of the outgoing nucleon and the lepton are determined by the interference between the resonant (RES) and nonresonant (NB) amplitudes. Moreover, the sign of the normal component of the polarization of the charged lepton is fixed by the relative sign between the RES and the NB amplitudes.

  20. Tilted Foils Nuclear Spin Polarization at REX-ISOLDE

    CERN Document Server

    Törnqvist, Hans Toshihide

    2013-08-08

    This thesis will explain and summarize my work and involvement in experiments aimed at producing nuclear spin polarization of post-accelerated beams of ions with the tilted-foils technique at the REX-ISOLDE linear accelerator at CERN. Polarizing the nuclear spin of radioactive beams in particular may provide access to observables which may be difficult to obtain otherwise. Currently, the techniques commonly employed for nuclear spin polarization are restricted to specific nuclides and experimental measurement techniques. Tilted foils polarization may provide a new tool to extend the range of nuclides that can be polarized and the types of experiments that can be performed. The experiments rely not only on the production but also on the method to measure the degree of attained polarization. Two methods will be treated, based on particle scattering in Coulomb excitation that may be utilized for stable beams, and the $\\beta$-NMR that requires $\\beta$-decaying nuclei. The experimental setups and measurements will...

  1. Utility of Machine-Learning Approaches to Identify Behavioral Markers for Substance Use Disorders: Impulsivity Dimensions as Predictors of Current Cocaine Dependence.

    Science.gov (United States)

    Ahn, Woo-Young; Ramesh, Divya; Moeller, Frederick Gerard; Vassileva, Jasmin

    2016-01-01

    Identifying objective and accurate markers of cocaine dependence (CD) can innovate its prevention and treatment. Existing evidence suggests that CD is characterized by a wide range of cognitive deficits, most notably by increased impulsivity. Impulsivity is multidimensional and it is unclear which of its various dimensions would have the highest predictive utility for CD. The machine-learning approach is highly promising for discovering predictive markers of disease. Here, we used machine learning to identify multivariate predictive patterns of impulsivity phenotypes that can accurately classify individuals with CD. Current cocaine-dependent users (N = 31) and healthy controls (N = 23) completed the self-report Barratt Impulsiveness Scale-11 and five neurocognitive tasks indexing different dimensions of impulsivity: (1) Immediate Memory Task (IMT), (2) Stop-Signal Task, (3) Delay-Discounting Task (DDT), (4) Iowa Gambling Task (IGT), and (5) Probabilistic Reversal-Learning task. We applied a machine-learning algorithm to all impulsivity measures. Machine learning accurately classified individuals with CD and predictions were generalizable to new samples (area under the curve of the receiver-operating characteristic curve was 0.912 in the test set). CD membership was predicted by higher scores on motor and non-planning trait impulsivity, poor response inhibition, and discriminability on the IMT, higher delay discounting on the DDT, and poor decision making on the IGT. Our results suggest that multivariate behavioral impulsivity phenotypes can predict CD with high degree of accuracy, which can potentially be used to assess individuals' vulnerability to CD in clinical settings.

  2. Utility of machine learning approaches to identify behavioral markers for substance use disorders: Impulsivity dimensions as predictors of current cocaine dependence

    Directory of Open Access Journals (Sweden)

    Woo-Young eAhn

    2016-03-01

    Full Text Available Background: Identifying objective and accurate markers of cocaine dependence (CD can innovate its prevention and treatment. Existing evidence suggests that CD is characterized by a wide range of cognitive deficits, most notably by increased impulsivity. Impulsivity is multidimensional and it is unclear which of its various dimensions would have the highest predictive utility for CD. The machine learning approach is highly promising for discovering predictive markers of disease. Here we used machine learning to identify multivariate predictive patterns of impulsivity phenotypes that can accurately classify individuals with CD. Methods: Current cocaine-dependent users (N=31 and healthy controls (N=23 completed the self-report Barratt Impulsiveness Scale (BIS-11 and five neurocognitive tasks indexing different dimensions of impulsivity: (1 Immediate Memory Task (IMT; (2 Stop-Signal Task (SST; (3 Delay-Discounting Task (DDT; (4 Iowa Gambling Task (IGT; and (5 Probabilistic Reversal Learning (PRL task. We applied a machine learning algorithm to all impulsivity measures. Results: Machine learning accurately classified individuals with CD and predictions were generalizable to new samples (area under the curve of the ROC curve was 0.912 in the test set. CD membership was predicted by higher scores on motor and non-planning trait impulsivity, poor response inhibition and discriminability on the IMT, higher delay discounting on the DDT, and poor decision-making on the IGT.Conclusions: Our results suggest that multivariate behavioral impulsivity phenotypes can predict CD with high degree of accuracy, which can potentially be used to assess individuals’ vulnerability to CD in clinical settings.

  3. Lobbying and political polarization

    OpenAIRE

    Ursprung, Heinrich W.

    2002-01-01

    Standard spatial models of political competition give rise to equilibria in which the competing political parties or candidates converge to a common position. In this paper I show how political polarization can be generated in models that focus on the nexus between pre-election interest group lobbying and electoral competition.

  4. Fluorescence confocal polarizing microscopy

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  5. Polarization of Bremsstrahlung

    International Nuclear Information System (INIS)

    Miller, J.

    1957-01-01

    The numerical results for the polarization of Bremsstrahlung are presented. The multiple scattering of electrons in the target is taken into account. The angular-and photon energy dependences are seen on the curves for an incident 25 MeV electron energy. (Author) [fr

  6. DESY: HERA polarization

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization

  7. Graphics of polar figure

    International Nuclear Information System (INIS)

    Macias B, L.R.

    1991-11-01

    The objective of this work, is that starting from a data file coming from a spectra that has been softened, and of the one that have been generated its coordinates to project it in stereographic form, to create the corresponding polar figure making use of the Cyber computer of the ININ by means of the GRAPHOS package. This work only requires a Beta, Fi and Intensity (I) enter data file. It starts of the existence of a softened spectra of which have been generated already with these data, making use of some language that in this case was FORTRAN for the Cyber computer, a program is generated supported in the Graphos package that allows starting of a reading of the Beta, Fi, I file, to generate the points in a stereographic projection and that it culminates with the graph of the corresponding polar figure. The program will request the pertinent information that is wanted to capture in the polar figure just as: date, name of the enter file, indexes of the polar figure, number of levels, radio of the stereographic projection (cms.), crystalline system to which belongs the sample, name the neuter graph file by create and to add the own general data. (Author)

  8. Coccolithophorids in polar waters: Trigonaspis spp. revisited

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Østergaard, Jette B.

    2015-01-01

    of crystallites that cover the surfaces of both the tower-shaped flagellar pole coccoliths and the disc-shaped body coccoliths are the keystone features of the genus. Circumstantial evidence exists linking species of Trigonaspis with species of Pappomonas in haploid-diploid life cycles.......A group of weakly calcified coccolithophorid genera and species were described from polar regions several decades ago. In the interim period a few additional findings have been reported adding to the morphological and biogeographical databases of some of the species. The holococcolithophorid genus...... Trigonaspis is revisited here with the purpose of providing, based on additional sampling from both polar regions, an update on species morphology, life history aspects and biogeography. The genus Trigonaspis as currently circumscribed comprises four taxa – two from each polar region. The triangular plates...

  9. Detailed analysis of evolution of the state of polarization in all-fiber polarization transformers.

    Science.gov (United States)

    Zhu, Xiushan; Jain, Ravinder K

    2006-10-30

    We present a detailed analysis of key attributes and performance characteristics of controllably-spun birefringent-fiber-based all-fiber waveplates or "all fiber polarization transformers" (AFPTs), first proposed and demonstrated by Huang [11]; these AFPTs consist essentially of a long carefully-designed "spin-twisted" high-birefringence fiber, fabricated by slowly varying the spin rate of a birefringent fiber preform (either from very fast to very slow or vice versa) while the fiber is being drawn. The evolution of the eigenstate from a linear polarization state to a circular polarization state, induced by slow variation of the intrinsic structure from linear anisotropy at the unspun end to circular anisotropy at the fast-spun end, enables the AFPT to behave like an all-fiber quarter-wave plate independent of the wavelength of operation. Power coupling between local eigenstates causes unique evolution of the polarization state along the fiber, and has been studied to gain insight into - as well as to understand detailed characteristics of -- the polarization transformation behavior. This has been graphically illustrated via plots of the relative power in these local eigenstates as a function of distance along the length of the fiber and plots of the extinction ratio of the output state of polarization (SOP) as a function of distance and the normalized spin rate. Deeper understanding of such polarization transformers has been further elucidated by quantitative calculations related to two crucial requirements for fabricating practical AFPT devices. Our calculations have also indicated that the polarization mode dispersion behaviour of the AFPT is much smaller than that of the original birefringent fiber. Finally, a specific AFPT was experimentally investigated at two widely-separated wavelengths (1310 nm and 1550 nm) of interest in telecommunications systems applications, further demonstrating and elucidating the broadband character of such AFPTs.

  10. Characteristics of volume polarization holography with linear polarization light

    Science.gov (United States)

    Zang, Jinliang; Wu, An'an; Liu, Ying; Wang, Jue; Lin, Xiao; Tan, Xiaodi; Shimura, Tsutomu; Kuroda, Kazuo

    2015-10-01

    Volume polarization holographic recording in phenanthrenequinone-doped poly(methyl methacrylate) (PQ-PMMA) photopolymer with linear polarized light is obtained. The characteristics of the volume polarization hologram are experimentally investigated. It is found that beyond the paraxial approximation the polarization states of the holographic reconstruction light are generally different from the signal light. Based on vector wave theoretical analyses and material properties, the special exposure condition for correctly holographic reconstruction is obtained and experimentally demonstrated.

  11. Verbal behavior

    OpenAIRE

    Michael, Jack

    1984-01-01

    The recent history and current status of the area of verbal behavior are considered in terms of three major thematic lines: the operant conditioning of adult verbal behavior, learning to be an effective speaker and listener, and developments directly related to Skinner's Verbal Behavior. Other topics not directly related to the main themes are also considered: the work of Kurt Salzinger, ape-language research, and human operant research related to rule-governed behavior.

  12. Effect of manganese doping on remnant polarization and leakage current in (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.10,Sb0.06)O3 epitaxial thin films on SrTiO3

    Science.gov (United States)

    Abazari, M.; Akdoǧan, E. K.; Safari, A.

    2008-05-01

    Single phase, epitaxial, ⟨001⟩ oriented, undoped and 1mol% Mn-doped (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.10,Sb0.06)O3 thin films of 400nm thickness were synthesized on SrRuO3 coated SrTiO3. Such films exhibit well saturated hysteresis loops and have a spontaneous polarization (Ps) of 10μC /cm2, which is a 150% higher over the Ps of the undoped composition. The coercive field of 1mol% Mn doped films is 13kV/cm. Mn-doping results in three orders of magnitude decrease in leakage current above 50kV/cm electric field, which we attribute to the suppression of intrinsic p-type conductivity of undoped films by Mn donors.

  13. Current Perspectives on Interventions for Self-Injurious Behavior of Children with Autism Spectrum Disorder: A Systematic Review of the Literature

    Science.gov (United States)

    Chezan, Laura C.; Gable, Robert A.; McWhorter, Gabriela Z.; White, Sherita D.

    2017-01-01

    Our purpose in this systematic review was to identify, evaluate, and summarize the single-case research design studies examining behavioral interventions to address self-injurious behavior for young children with autism spectrum disorder. We identified 24 studies published between 2000 and 2016 that met the inclusion criteria. We reviewed and…

  14. Spin-polarized current effects in disordered La{sub 0.7}Ba{sub 0.3}MnO{sub 3} half-metal thin films

    Energy Technology Data Exchange (ETDEWEB)

    Barone, C; Aruta, C; Orgiani, P; Maritato, L; Pagano, S [CNR-SPIN Salerno and Dipartimento di Matematica e Informatica, Universita di Salerno, Fisciano (Italy); Galdi, A [CNR-SPIN Salerno and Dipartimento di Fisica ' E.R. Caianiello' , Universita di Salerno, Fisciano (Italy); Quaranta, O, E-mail: cbarone@unisa.i [NEST CNR-INFM and Scuola Normale Superiore, I-56126 Pisa (Italy)

    2010-06-23

    We have investigated by means of noise spectroscopy the transport properties of half-metal La{sub 0.7}Ba{sub 0.3}MnO{sub 3} (LBMO) thin films deposited on MgO substrates. A reduced metal-insulator transition temperature and a peculiar noise behaviour are observed in the films grown on MgO substrates, when compared with similar films grown on SrTiO{sub 3} substrates. In particular, a large increase in noise is observed below the metal-insulator transition temperature, associated with a current induced reduction in the excess noise level. This finding is explained in terms of the spin torque effect between regions with depressed Curie temperatures among the ferromagnetic metallic domains. The proposed theoretical model, taking into account the half-metal character of manganites, describes well the experimental data.

  15. Experiments with Fermilab polarized proton and polarized antiproton beams

    International Nuclear Information System (INIS)

    Yokosawa, A.

    1990-01-01

    We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the π degree production at high p perpendicular and in the Λ (Σ degree), π ± , π degree production at large x F , and Δσ L (pp, bar pp) measurements. 18 refs

  16. NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

    NARCIS (Netherlands)

    SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

    1993-01-01

    Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,

  17. Joule heating and spin-transfer torque investigated on the atomic scale using a spin-polarized scanning tunneling microscope.

    Science.gov (United States)

    Krause, S; Herzog, G; Schlenhoff, A; Sonntag, A; Wiesendanger, R

    2011-10-28

    The influence of a high spin-polarized tunnel current onto the switching behavior of a superparamagnetic nanoisland on a nonmagnetic substrate is investigated by means of spin-polarized scanning tunneling microscopy. A detailed lifetime analysis allows for a quantification of the effective temperature rise of the nanoisland and the modification of the activation energy barrier for magnetization reversal, thereby using the nanoisland as a local thermometer and spin-transfer torque analyzer. Both the Joule heating and spin-transfer torque are found to scale linearly with the tunnel current. The results are compared to experiments performed on lithographically fabricated magneto-tunnel junctions, revealing a very high spin-transfer torque switching efficiency in our experiments.

  18. Polarized electron beams at SLAC

    International Nuclear Information System (INIS)

    Moffeit, K.C.

    1992-11-01

    SLAC has successfully accelerated high energy polarized electrons for the Stanford Linear Collider and fixed polarized nuclear target experiments. The polarized electron beams at SLAC use a gallium arsenide (GaAlAs for E-142) photon emission source to provide the beam of polarized electrons with polarization of approximately 28% (41% for E-142). While the beam emittance is reduced in the damping ring for SLC operation a system of bend magnets and superconducting solenoids preserve and orient the spin direction for maximum longitudinal polarization at the collision point. The electron polarization is monitored with a Compton scattering polarimeter, and was typically 22% at the e+e- collision point for the 1992 run. Improvements are discussed to increase the source polarization and to reduce the depolarization effects between the source and the collision point

  19. Analytical polarization calculations beyond SLIM

    International Nuclear Information System (INIS)

    Barber, D.P.

    1989-01-01

    A comparison is made between the theories of Bell and Leinaas and of Derbenev and Kondratenko for the spin polarization in electron storage rings. A calculation of polarization in HERA using the program SMILE of Mane is presented

  20. On Determinants of Political Polarization

    OpenAIRE

    Grechyna, Daryna

    2015-01-01

    Political polarization has been shown to significantly influence a country's economic performance. However, little is known about the drivers of political polarization. In this article, we aim to identify the main determinants of political polarization using Bayesian Model Averaging to overcome the problem of model uncertainty. We find that the level of trust within a country and the degree of income inequality are the most robust determinants of political polarization.

  1. Neutron stars with spin polarized self-interacting dark matter

    OpenAIRE

    Rezaei, Zeinab

    2018-01-01

    Dark matter, one of the important portion of the universe, could affect the visible matter in neutron stars. An important physical feature of dark matter is due to the spin of dark matter particles. Here, applying the piecewise polytropic equation of state for the neutron star matter and the equation of state of spin polarized self-interacting dark matter, we investigate the structure of neutron stars which are influenced by the spin polarized self-interacting dark matter. The behavior of the...

  2. Polarity controlled reaction path and kinetics of thermal cis-to-trans isomerization of 4-aminoazobenzene.

    Science.gov (United States)

    Joshi, Neeraj Kumar; Fuyuki, Masanori; Wada, Akihide

    2014-02-20

    Spectral and kinetic behavior of thermal cis-to-trans isomerization of 4-aminoazobenzene (AAB) is examined in various solvents of different polarities. In contrast to azobenzene (AB), it is found the rate of thermal isomerization of AAB is highly dependent on solvent polarity. Accelerated rates are observed in polar solvents as compared to nonpolar solvents. Moreover, a decrease in the barrier height with an increase in medium polarity is observed. Our observations suggest that inversion is the preferred pathway in cis-to-trans thermal isomerization in a nonpolar medium; however, in a polar medium, the isomerization path deviates from the inversion route and rotational behavior is incorporated. Differences in the kinetics and in mechanisms of isomerization in different media are rationalized in terms of modulation in barrier height by polarity of the medium and solute-solvent interaction. It is found that kinetics as well as the mechanism of thermal isomerization in AAB is controlled by the polarity of the medium.

  3. Effect of stray current on corrosion behavior of reinforcing steel: importance of cell geometry and orientation with respect to the electrical field

    NARCIS (Netherlands)

    Chen, Zhipei; Koleva, D.A.

    2016-01-01

    Stray current circulating in reinforced concrete structures may initiate corrosion or accelerate existing corrosion processes on embedded reinforcement. In some cases, the range of dangerous or unwanted interactions of stray currents under favorable conditions (environment), is much broader than is

  4. Spin-polarized light-emitting diodes based on organic bipolar spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Vardeny, Zeev Valentine; Nguyen, Tho Duc; Ehrenfreund, Eitan Avraham

    2017-10-25

    Spin-polarized organic light-emitting diodes are provided. Such spin-polarized organic light-emitting diodes incorporate ferromagnetic electrodes and show considerable spin-valve magneto-electroluminescence and magneto-conductivity responses, with voltage and temperature dependencies that originate from the bipolar spin-polarized space charge limited current.

  5. Polarized electrogowdy spacetimes censored

    Energy Technology Data Exchange (ETDEWEB)

    Nungesser, Ernesto, E-mail: ernesto.nungesser@aei.mpg.d [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)

    2010-05-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  6. PEPPo: Using a Polarized Electron Beam to Produce Polarized Positrons

    Energy Technology Data Exchange (ETDEWEB)

    Adeyemi, Adeleke H. [Hampton Univ., Hampton, VA (United States); et al.

    2015-09-01

    Polarized positron beams have been identified as either an essential or a significant ingredient for the experimental program of both the present and next generation of lepton accelerators (JLab, Super KEK B, ILC, CLIC). An experiment demonstrating a new method for producing polarized positrons has been performed at the Continuous Electron Beam Accelerator Facility at Jefferson Lab. The PEPPo (Polarized Electrons for Polarized Positrons) concept relies on the production of polarized e⁻/e⁺ pairs from the bremsstrahlung radiation of a longitudinally polarized electron beam interacting within a high-Z conversion target. PEPPo demonstrated the effective transfer of spin-polarization of an 8.2 MeV/c polarized (P~85%) electron beam to positrons produced in varying thickness tungsten production targets, and collected and measured in the range of 3.1 to 6.2 MeV/c. In comparison to other methods this technique reveals a new pathway for producing either high-energy or thermal polarized positron beams using a relatively low polarized electron beam energy (~10MeV) .This presentation will describe the PEPPo concept, the motivations of the experiment and high positron polarization achieved.

  7. Polarization induced doped transistor

    Science.gov (United States)

    Xing, Huili; Jena, Debdeep; Nomoto, Kazuki; Song, Bo; Zhu, Mingda; Hu, Zongyang

    2016-06-07

    A nitride-based field effect transistor (FET) comprises a compositionally graded and polarization induced doped p-layer underlying at least one gate contact and a compositionally graded and doped n-channel underlying a source contact. The n-channel is converted from the p-layer to the n-channel by ion implantation, a buffer underlies the doped p-layer and the n-channel, and a drain underlies the buffer.

  8. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  9. Multifrequency Behaviour of Polars

    Directory of Open Access Journals (Sweden)

    K. Reinsch

    2015-02-01

    Full Text Available Cataclysmic variables emit over a wide range of the electromagnetic spectrum. In this paper I will review observations of polars in relevant passbands obtained during the last decade and will discuss their diagnostical potential to access the physics of the main components within the binary systems. This will include a discussion of intrinsic source variability and the quest for simultaneous multi-frequency observations.

  10. Molecular electron recollision dynamics in intense circularly polarized laser pulses

    Science.gov (United States)

    Bandrauk, André D.; Yuan, Kai-Jun

    2018-04-01

    Extreme UV and x-ray table top light sources based on high-order harmonic generation (HHG) are focused now on circular polarization for the generation of circularly polarized attosecond pulses as new tools for controlling electron dynamics, such as charge transfer and migration and the generation of attosecond quantum electron currents for ultrafast magneto-optics. A fundamental electron dynamical process in HHG is laser induced electron recollision with the parent ion, well established theoretically and experimentally for linear polarization. We discuss molecular electron recollision dynamics in circular polarization by theoretical analysis and numerical simulation. The control of the polarization of HHG with circularly polarized ionizing pulses is examined and it is shown that bichromatic circularly polarized pulses enhance recollision dynamics, rendering HHG more efficient, especially in molecules because of their nonspherical symmetry. The polarization of the harmonics is found to be dependent on the compatibility of the rotational symmetry of the net electric field created by combinations of bichromatic circularly polarized pulses with the dynamical symmetry of molecules. We show how the field and molecule symmetry influences the electron recollision trajectories by a time-frequency analysis of harmonics. The results, in principle, offer new unique controllable tools in the study of attosecond molecular electron dynamics.

  11. Polar Business Design

    Directory of Open Access Journals (Sweden)

    Sébastien Caisse

    2014-02-01

    Full Text Available Polar business design aims to enable entrepreneurs, managers, consultants, researchers, and business students to better tackle model-based analysis, creation, and transformation of businesses, ventures, and, more generically, collective endeavors of any size and purpose. It is based on a systems-thinking approach that builds on a few interrelated core concepts to create holistic visual frameworks. These core concepts act as poles linked by meaningful dyads, flows, and faces arranged in geometric shapes. The article presents two such polar frameworks as key findings in an ongoing analytic autoethnography: the three-pole Value−Activity−Stakeholder (VAS triquetra and the four-pole Offer−Creation−Character−Stakeholder (OCCS tetrahedron. The VAS triquetra is a more aggregated model of collective endeavors. The OCCS tetrahedron makes a trade-off between a steeper learning curve and deeper, richer representation potential. This article discusses how to use these two frameworks as well as their limits, and explores the potential that polar business design offers for future research.

  12. Bending-Induced Giant Polarization in Ferroelectric MEMS Diaphragm

    KAUST Repository

    Wang, Zhihong

    2016-09-09

    The polarization induced by the strain gradient, i.e. the flexoelectric effect, has been observed in a micromachined Pb(Zr0.52Ti0.48)O3 (PZT) diaphragms. Applying air pressure to bend a flat diaphragm which initially does not exhibit any electromechanical coupling can induce a resonance peak in its impedance spectrum. This result supposes that bending, thus the strain gradient in the diaphragm causes polarization in PZT film. We also investigated the switching behaviors of the polarization in response to an external electric field in a bent diaphragm and further quantified the polarization induced by the strain gradient. The effective flexoelectric coefficient of the PZT film has been calculated as large as 2.0 × 10−4 C/m. A giant flexoelectric polarization of the order of 1 μC/cm2 was characterized which is of the same order of magnitude as the normal remnant ferroelectric polarization of PZT film. The suggested explanation for the giant polarization is the large strain gradient in the diaphragm and the strain gradient induced reorientation of the polar nanodomains.

  13. Development of polarized negative hydrogen ion source with resonant charge-exchange plasma ionizer

    Science.gov (United States)

    Belov, A. S.; Esin, S. K.; Netchaeva, L. P.; Turbabin, A. V.; Vasil'Ev, G. A.

    2001-06-01

    Polarized negative hydrogen ion beam with peak current of 2.5 mA has been obtained from an atomic beam-type polarized ion source of Institute for Nuclear Research, Moscow. The intensity improvement has been achieved due to increase of efficiency of conversion of polarized hydrogen atoms into polarized negative ions. New converter for production of deuterium plasma with high density of unpolarized negative ions is described. Limitations of the method and possible improvements are discussed. .

  14. A numerical assessment of rough surface scattering theories. I - Horizontal polarization. II - Vertical polarization

    Science.gov (United States)

    Rodriguez, Ernesto; Kim, Yunjin; Durden, Stephen L.

    1992-01-01

    A numerical evaluation is presented of the regime of validity for various rough surface scattering theories against numerical results obtained by employing the method of moments. The contribution of each theory is considered up to second order in the perturbation expansion for the surface current. Considering both vertical and horizontal polarizations, the unified perturbation method provides best results among all theories weighed.

  15. Ab initio theory for current-induced molecular switching: Melamine on Cu(001)

    KAUST Repository

    Ohto, Tatsuhiko

    2013-05-28

    Melamine on Cu(001) is mechanically unstable under the current of a scanning tunneling microscope tip and can switch among configurations. However, these are not equally accessible, and the switching critical current depends on the bias polarity. In order to explain such rich phenomenology, we have developed a scheme to evaluate the evolution of the reaction paths and activation barriers as a function of bias, which is rooted in the nonequilibrium Green\\'s function method implemented within density functional theory. This, combined with the calculation of the inelastic electron tunneling spectroscopy signal, allows us to identify the vibrational modes promoting the observed molecular conformational changes. Finally, once our ab initio results are used within a resonance model, we are able to explain the details of the switching behavior, such as its dependence on the bias polarity, and the noninteger power relation between the reaction rate constants and both the bias voltage and the electric current. © 2013 American Physical Society.

  16. Bringing Polar Science to the Classroom

    Science.gov (United States)

    Bruccoli, A.; Madsen, J. M.; Porter, M.

    2004-12-01

    The NSF sponsored IceCube (OPP-0236449) and Teachers Experiencing Antarctica and the Arctic (TEA) projects have developed a model for engaging K-12 teachers in a variety of scientific disciplines using polar science as a unifying theme. An intensive workshop, Science in the Ice, provided teachers with background content knowledge and seed ideas for activities aligned with national teaching standards. These activities were used to support the introduction of authentic science investigations related to current polar research in the classroom. The pilot workshop, sponsored by the NSF supported Math-Science Partnership SCALE (0227016), demonstrated the viability of this approach for involving a continuum of teachers from novice to master in a meaningful professional development model that can lead to sustainable classroom changes. This model for teacher professional development is based on the premise that the most robust educational outreach efforts involve teachers that are prepared, supported, and connected to a network of researchers and educators. This network can also serve to both stimulate interest in polar research and as a vehicle for delivering classroom materials related to the International Polar Year. An overview of Science in the Ice will be provided to show how the natural fascination with extreme environments can be used to introduce on-going research to the classroom from multiple disciplines---glaciology, geology, and astrophysics---with a common thread of polar science. The case for involving teachers now to fully capitalize on the potential of the International Polar Year, by providing professional development opportunities including field experiences with researchers, will be made.

  17. Ventral polarization vision in tabanids: horseflies and deerflies (Diptera: Tabanidae) are attracted to horizontally polarized light

    Science.gov (United States)

    Horváth, Gábor; Majer, József; Horváth, Loránd; Szivák, Ildikó; Kriska, György

    2008-11-01

    Adult tabanid flies (horseflies and deerflies) are terrestrial and lay their eggs onto marsh plants near bodies of fresh water because the larvae develop in water or mud. To know how tabanids locate their host animals, terrestrial rendezvous sites and egg-laying places would be very useful for control measures against them, because the hematophagous females are primary/secondary vectors of some severe animal/human diseases/parasites. Thus, in choice experiments performed in the field we studied the behavior of tabanids governed by linearly polarized light. We present here evidence for positive polarotaxis, i.e., attraction to horizontally polarized light stimulating the ventral eye region, in both males and females of 27 tabanid species. The novelty of our findings is that positive polarotaxis has been described earlier only in connection with the water detection of some aquatic insects ovipositing directly into water. A further particularity of our discovery is that in the order Diptera and among blood-sucking insects the studied tabanids are the first known species possessing ventral polarization vision and definite polarization-sensitive behavior with known functions. The polarotaxis in tabanid flies makes it possible to develop new optically luring traps being more efficient than the existing ones based on the attraction of tabanids by the intensity and/or color of reflected light.

  18. Combined Effect of Alternating Current Interference and Cathodic Protection on Pitting Corrosion and Stress Corrosion Cracking Behavior of X70 Pipeline Steel in Near-Neutral pH Environment

    Directory of Open Access Journals (Sweden)

    Liwei Wang

    2018-03-01

    Full Text Available Influence of alternating current (AC on pitting corrosion and stress corrosion cracking (SCC behavior of X70 pipeline steel in the near-neutral pH environment under cathodic protection (CP was investigated. Both corrosion and SCC are inhibited by −0.775 VSCE CP without AC interference. With the superimposition of AC current (1–10 mA/cm2, the direct current (DC potential shifts negatively under the CP of −0.775 VSCE and the cathodic DC current decreases and shifts to the anodic direction. Under the CP potential of −0.95 VSCE and −1.2 VSCE, the applied AC current promotes the cathodic reaction and leads to the positive shift of DC potential and increase of cathodic current. Local anodic dissolution occurs attributing to the generated anodic current transients in the positive half-cycle of the AC current, resulting in the initiation of corrosion pits (0.6–2 μm in diameter. AC enhances the SCC susceptibility of X70 steel under −0.775 VSCE CP, attributing to the promotion of anodic dissolution and hydrogen evolution. Even an AC current as low as 1 mA/cm2 can enhance the SCC susceptibility.

  19. Combined Effect of Alternating Current Interference and Cathodic Protection on Pitting Corrosion and Stress Corrosion Cracking Behavior of X70 Pipeline Steel in Near-Neutral pH Environment.

    Science.gov (United States)

    Wang, Liwei; Cheng, Lianjun; Li, Junru; Zhu, Zhifu; Bai, Shuowei; Cui, Zhongyu

    2018-03-22

    Influence of alternating current (AC) on pitting corrosion and stress corrosion cracking (SCC) behavior of X70 pipeline steel in the near-neutral pH environment under cathodic protection (CP) was investigated. Both corrosion and SCC are inhibited by -0.775 V SCE CP without AC interference. With the superimposition of AC current (1-10 mA/cm²), the direct current (DC) potential shifts negatively under the CP of -0.775 V SCE and the cathodic DC current decreases and shifts to the anodic direction. Under the CP potential of -0.95 V SCE and -1.2 V SCE , the applied AC current promotes the cathodic reaction and leads to the positive shift of DC potential and increase of cathodic current. Local anodic dissolution occurs attributing to the generated anodic current transients in the positive half-cycle of the AC current, resulting in the initiation of corrosion pits (0.6-2 μm in diameter). AC enhances the SCC susceptibility of X70 steel under -0.775 V SCE CP, attributing to the promotion of anodic dissolution and hydrogen evolution. Even an AC current as low as 1 mA/cm² can enhance the SCC susceptibility.

  20. Circular polarization in a non-magnetic resonant tunneling device

    Directory of Open Access Journals (Sweden)

    Airey Robert

    2011-01-01

    Full Text Available Abstract We have investigated the polarization-resolved photoluminescence (PL in an asymmetric n-type GaAs/AlAs/GaAlAs resonant tunneling diode under magnetic field parallel to the tunnel current. The quantum well (QW PL presents strong circular polarization (values up to -70% at 19 T. The optical emission from GaAs contact layers shows evidence of highly spin-polarized two-dimensional electron and hole gases which affects the spin polarization of carriers in the QW. However, the circular polarization degree in the QW also depends on various other parameters, including the g-factors of the different layers, the density of carriers along the structure, and the Zeeman and Rashba effects.