18,398 research outputs found
Downright Sexy: Verticality, Implicit Power, and Perceived Physical Attractiveness
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
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 C excited by few-cycle laser pulses
We theoretically analyze angle-resolved photo-electron spectra (ARPES)
generated by the interaction of C 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
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 NdCuO
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
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 Vm/W and Vm/W with the heat flux method
and V/K and 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
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
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
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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