18,017 research outputs found

    Downright Sexy: Verticality, Implicit Power, and Perceived Physical Attractiveness

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    Grounded theory proposes that abstract concepts (e.g., power) are represented by perceptions of vertical space (e.g., up is powerful; down is powerless). We used this theory to examine predictions made by evolutionary psychologists who suggest that desirable males are those who have status and resources (i.e., powerful) while desirable females are those who are youthful and faithful (i.e., powerless). Using vertical position as an implicit cue for power, we found that male participants rated pictures of females as more attractive when their images were presented near the bottom of a computer screen, whereas female participants rated pictures of males as more attractive when their images were presented near the top of a computer screen. Our results support the evolutionary theory of attraction and reveal the social-judgment consequences of grounded theories of cognition

    Supersaturated dispersions of rod-like viruses with added attraction

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    The kinetics of isotropic-nematic (I-N) and nematic-isotropic (N-I) phase transitions in dispersions of rod-like {\it fd}-viruses are studied. Concentration quenches were applied using pressure jumps in combination with polarization microscopy, birefringence and turbidity measurements. The full biphasic region could be accessed, resulting in the construction of a first experimental analogue of the bifurcation diagram. The N-I spinodal points for dispersions of rods with varying concentrations of depletion agents (dextran) were obtained from orientation quenches, using cessation of shear flow in combination with small angle light scattering. We found that the location of the N-I spinodal point is independent of the attraction, which was confirmed by theoretical calculations. Surprisingly, the experiments showed that also the absolute induction time, the critical nucleus and the growth rate are insensitive of the attraction, when the concentration is scaled to the distance to the phase boundaries.Comment: 13 pages, 14 figures. accepted in Phsical Review

    Forward-backward asymmetry of photoemission in C60_{60} excited by few-cycle laser pulses

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    We theoretically analyze angle-resolved photo-electron spectra (ARPES) generated by the interaction of C60_{60} with intense, short laser pulses. In particular, we focus on the impact of the carrier-envelope phase (CEP) onto the angular distribution. The electronic dynamics is described by time-dependent density functional theory, and the ionic background of \csixty is approximated by a particularly designed jellium model. Our results show a clear dependence of the angular distributions onto the CEP for very short pulses covering only very few laser cycles, which disappears for longer pulses. For the specific laser parameters used in a recent experiments, a very good agreement is obtained. Furthermore, the asymmetry is found to depend on the energy of the emitted photoelectrons. The strong influence of the angular asymmetry of electron emission onto the CEP and pulse duration suggests to use this sensitivity as a means to analyze the structure of few-cycle laser pulses.Comment: 8 pages, 6 figure

    Gas phase polymerization of ethylene with a silica-supported metallocene catalyst: influence of temperature on deactivation

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    Ethylene was polymerized at 5 bar in a stirred powder bed reactor with silica supported rac-Me2Si[Ind]2ZrCl2/methylaluminoxane (MAO) at temperatures between 40°C and 80°C using NaCl as support bed and triethylaluminium (TEA) as a scavenger for impurities. For this fixed recipe and a given charge of catalyst. the average catalyst activity is reproducible within 10% for low temperatures. The polymerization rate and the rate of deactivation increase with increasing temperature. The deactivation could be modeled using a first order dependence with respect to the polymerization rate

    First principles study of local electronic and magnetic properties in pure and electron-doped Nd2_2CuO4_4

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    The local electronic structure of Nd2CuO4 is determined from ab-initio cluster calculations in the framework of density functional theory. Spin-polarized calculations with different multiplicities enable a detailed study of the charge and spin density distributions, using clusters that comprise up to 13 copper atoms in the CuO2plane. Electron doping is simulated by two different approaches and the resulting changes in the local charge distribution are studied in detail and compared to the corresponding changes in hole doped La2CuO4. The electric field gradient (EFG) at the copper nucleus is investigated in detail and good agreement is found with experimental values. In particular the drastic reduction of the main component of the EFG in the electron-doped material with respect to LaCuO4 is explained by a reduction of the occupancy of the 3d3z^2-r^2 atomic orbital. Furthermore, the chemical shieldings at the copper nucleus are determined and are compared to results obtained from NMR measurements. The magnetic hyperfine coupling constants are determined from the spin density distribution

    Longitudinal spin Seebeck coefficient: heat flux vs. temperature difference method

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    The determination of the longitudinal spin Seebeck effect (LSSE) coefficient is currently plagued by a large uncertainty due to the poor reproducibility of the experimental conditions used in its measurement. In this work we present a detailed analysis of two different methods used for the determination of the LSSE coefficient. We have performed LSSE experiments in different laboratories, by using different setups and employing both the temperature difference method and the heat flux method. We found that the lack of reproducibility can be mainly attributed to the thermal contact resistance between the sample and the thermal baths which generate the temperature gradient. Due to the variation of the thermal resistance, we found that the scaling of the LSSE voltage to the heat flux through the sample rather than to the temperature difference across the sample greatly reduces the uncertainty. The characteristics of a single YIG/Pt LSSE device obtained with two different setups was (1.143±0.007)107(1.143\pm0.007)\cdot 10^{-7} Vm/W and (1.101±0.015)107(1.101\pm0.015)\cdot 10^{-7} Vm/W with the heat flux method and (2.313±0.017)107(2.313\pm0.017)\cdot 10^{-7} V/K and (4.956±0.005)107(4.956\pm0.005)\cdot 10^{-7} V/K with the temperature difference method. This shows that systematic errors can be considerably reduced with the heat flux method.Comment: PDFLaTeX, 10 pages, 6 figure

    An extreme ultraviolet spectrometer experiment for the Shuttle Get Away Special Program

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    An extreme ultraviolet (EUV) spectrometer experiment operated successfully during the STS-7 mission in an experiment to measure the global and diurnal variation of the EUV airglow. The spectrometer is an F 3.5 Wadsworth mount with mechanical collimator, a 75 x 75 mm grating, and a bare microchannel plate detector providing a spectral resolution of 7 X FWHM. Read-out of the signal is through discrete channels or resistive anode techniques. The experiment includes a microcomputer, 20 Mbit tape recorder, and a 28V, 40 Ahr silver-zinc battery. It is the first GAS payload to use an opening door. The spectrometer's 0.1 x 4.2 deg field of view is pointed vertically out of the shuttle bay. During the STS-7 flight data were acquired continuously for a period of 5 hours and 37 minutes, providing spectra of the 570 A to 850 A wavelength region of the airglow. Five diurnal cycles of the 584 A emission of neutral helium and the 834 A emission of ionized atomic oxygen were recorded. The experiment also recorded ion events and pressure pulses associated with thruster firings. The experiment is to fly again on Mission 41-F

    Large-area sheet task advanced dendritic web growth development

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    The computer code for calculating web temperature distribution was expanded to provide a graphics output in addition to numerical and punch card output. The new code was used to examine various modifications of the J419 configuration and, on the basis of the results, a new growth geometry was designed. Additionally, several mathematically defined temperature profiles were evaluated for the effects of the free boundary (growth front) on the thermal stress generation. Experimental growth runs were made with modified J419 configurations to complement the modeling work. A modified J435 configuration was evaluated

    Stereo-selective swelling of imprinted cholesteric networks

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    Molecular chirality, and the chiral symmetry breaking of resulting macroscopic phases, can be topologically imprinted and manipulated by crosslinking and swelling of polymer networks. We present a new experimental approach to stereo-specific separation of chiral isomers by using a cholesteric elastomer in which a helical director distribution has been topological imprinted by crosslinking. This makes the material unusual in that is has a strong phase chirality, but no molecular chirality at all; we study the nature and parameters controlling the twist-untwist transition. Adding a racemic mixture to the imprinted network results in selective swelling by only the component of ``correct'' handedness. We investigate the capacity of demixing in a racemic environment, which depends on network parameters and the underlying nematic order
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