341 research outputs found
Preferences for facial and vocal masculinity in homosexual men: the role of relationship status, sexual restrictiveness, and self-perceived masculinity
Studies on mate preferences usually examine heterosexual attraction; comparatively little is known about preferences of individuals whose sexuality is aimed at the same sex. We examined preferences of two groups of androphilic individuals-homosexual men and heterosexual women- for male facial and vocal level of masculinity. Facial images of 58 men and vocal recordings of 30 men were rated by 51 heterosexual women and 33 homosexual men for their attractiveness and masculinity- femininity. In both groups of raters, ratings of vocal attractiveness and masculinity were positively correlated, but there was no overall preference for facial masculinity. After splitting raters according to their relationship status, sexual restrictiveness, and self-rated masculinity, we found significant preferences for masculine voices only in single homosexual men and coupled heterosexual women, while a preference for feminine male faces was found in coupled homosexual men. Furthermore, homosexual men describing themselves as relatively masculine significantly preferred masculine voices but also more feminine male faces. Our results demonstrate that conditional mate preferences are not restricted to heterosexual interactions, and homosexual men prefer a mixture of masculine and feminine traits in their potential male partners
Lepton Flavor Violation and the Tau Neutrino Mass
We point out that, in the left-right symmetric model of weak interaction, if
mass is in the keV to MeV range, there is a strong correlation
between rare decays such as and
the mass. In particular, we point out that a large range of
masses are forbidden by the cosmological constraints on
in combination with the present upper limits on these processes.Comment: UMDHEP 94-30, 14 pages, TeX file, (some new references added
Light Sterile Neutrino from extra dimensions and Four-Neutrino Solutions to Neutrino Anomalies
We propose a four-neutrino model which can reconcile the existing data coming
from underground experiments in terms of neutrino oscillations, together with
the hint from the LSND experiment and a possible neutrino contribution to the
hot dark matter of the Universe. It applies the idea that extra compact
dimensions, probed only by gravity and possibly gauge-singlet fields, can lower
the fundamental scales such as the Planck, string or unification scales. Our
fourth light neutrino ( for sterile) is identified with the zero
mode of the Kaluza-Klein states. To first approximation \nu_sterile combines
with the nu_mu in order to form a Dirac neutrino with mass in the eV range
leaving the other two neutrinos massless. The smallness of this mass scale
(suitable for LSND and Hot Dark Matter) arises without appealing neither to a
see-saw mechanism nor to a radiative mechanism, but from the volume factor
associated with the canonical normalization of the wave-function of the bulk
field in the compactified dimensions. % On the other hand the splitting between
\nm and \nu_sterile (atmospheric scale) as well as the mass of the two other
neutrinos (solar mass scale) arise from the violation of the fermion number on
distant branes. We also discuss alternative scenarios involving
flavour-changing interactions. In one of them \ne can be in the electron-volt
range and therefore be probed in beta decay studies.Comment: 12 pages, latex, no figures, title changed, final version to be
published in Phys Rev
Non-L\'evy mobility patterns of Mexican Me'Phaa peasants searching for fuelwood
We measured mobility patterns that describe walking trajectories of
individual Me'Phaa peasants searching and collecting fuelwood in the forests of
"La Monta\~na de Guerrero" in Mexico. These one-day excursions typically follow
a mixed pattern of nearly-constant steps when individuals displace from their
homes towards potential collecting sites and a mixed pattern of steps of
different lengths when actually searching for fallen wood in the forest.
Displacements in the searching phase seem not to be compatible with L\'evy
flights described by power-laws with optimal scaling exponents. These findings
however can be interpreted in the light of deterministic searching on heavily
degraded landscapes where the interaction of the individuals with their scarce
environment produces alternative searching strategies than the expected L\'evy
flights. These results have important implications for future management and
restoration of degraded forests and the improvement of the ecological services
they may provide to their inhabitants.Comment: 15 pages, 4 figures. First version submitted to Human Ecology. The
final publication will be available at http://www.springerlink.co
The Logic of Fashion Cycles
Many cultural traits exhibit volatile dynamics, commonly dubbed fashions or fads. Here we show that realistic fashion-like dynamics emerge spontaneously if individuals can copy others' preferences for cultural traits as well as traits themselves. We demonstrate this dynamics in simple mathematical models of the diffusion, and subsequent abandonment, of a single cultural trait which individuals may or may not prefer. We then simulate the coevolution between many cultural traits and the associated preferences, reproducing power-law frequency distributions of cultural traits (most traits are adopted by few individuals for a short time, and very few by many for a long time), as well as correlations between the rate of increase and the rate of decrease of traits (traits that increase rapidly in popularity are also abandoned quickly and vice versa). We also establish that alternative theories, that fashions result from individuals signaling their social status, or from individuals randomly copying each other, do not satisfactorily reproduce these empirical observations
Statistical mechanics of complex networks
Complex networks describe a wide range of systems in nature and society, much
quoted examples including the cell, a network of chemicals linked by chemical
reactions, or the Internet, a network of routers and computers connected by
physical links. While traditionally these systems were modeled as random
graphs, it is increasingly recognized that the topology and evolution of real
networks is governed by robust organizing principles. Here we review the recent
advances in the field of complex networks, focusing on the statistical
mechanics of network topology and dynamics. After reviewing the empirical data
that motivated the recent interest in networks, we discuss the main models and
analytical tools, covering random graphs, small-world and scale-free networks,
as well as the interplay between topology and the network's robustness against
failures and attacks.Comment: 54 pages, submitted to Reviews of Modern Physic
Femtosecond x-ray diffraction reveals a liquid–liquid phase transition in phase-change materials
6 pags., 5 figs.In phase-change memory devices, a material is cycled between glassy and crystalline states. The highly temperature-dependent kinetics of its crystallization process enables application in memory technology, but the transition has not been resolved on an atomic scale. Using femtosecond x-ray diffraction and ab initio computer simulations, we determined the time-dependent pair-correlation function of phase-change materials throughout the melt-quenching and crystallization process. We found a liquid–liquid phase transition in the phase-change materials AgInSbTe and GeSb at 660 and 610 kelvin, respectively. The transition is predominantly caused by the onset of Peierls distortions, the amplitude of which correlates with an increase of the apparent activation energy of diffusivity. This reveals a relationship between atomic structure and kinetics, enabling a systematic optimization of the memory-switching kinetics.F.Q., A.K., M.N., and K.S.T. gratefully acknowledge financial support
from the German Research Council through the Collaborative
Research Center SFB 1242 project 278162697 (“Non-Equilibrium
Dynamics of Condensed Matter in the Time Domain”), project C01
(“Structural Dynamics in Impulsively Excited Nanostructures”),
and individual grant So408/9-1, as well as the European Union
(7th Framework Programme, grant no. 280555 GO FAST). M.J.S.,
R.M., and M.W. acknowledge financial support from the German
Research Council through the Collaborative Research Center
SFB 917 (“Nanoswitches”) and individual grant Ma-5339/2-1.
M.J.S., I.R., and R.M. also acknowledge the computational resources
granted by JARA-HPC from RWTH Aachen University under project
nos. JARA0150 and JARA0183. M.T., A.M.L., and D.A.R. were
supported by the U.S. Department of Energy, Office of Science,
Office of Basic Energy Sciences, through the Division of Materials
Sciences and Engineering under contract no. DE-AC02-76SF00515.
This work was performed under the auspices of the U.S.
Department of Energy by Lawrence Livermore National Laboratory
under contract DE-AC52-07NA27344. J.L. acknowledges support
from the Swedish Research Council. J.S. acknowledges financial
support from the Spanish Ministry of Science, Innovation and
Universities through research grant UDiSON (TEC2017-82464-R).
P.Z. gratefully acknowledges funding by the Humboldt Foundatio
A Herpesvirus Encoded Deubiquitinase Is a Novel Neuroinvasive Determinant
The neuroinvasive property of several alpha-herpesviruses underlies an uncommon infectious process that includes the establishment of life-long latent infections in sensory neurons of the peripheral nervous system. Several herpesvirus proteins are required for replication and dissemination within the nervous system, indicating that exploiting the nervous system as a niche for productive infection requires a specialized set of functions encoded by the virus. Whether initial entry into the nervous system from peripheral tissues also requires specialized viral functions is not known. Here we show that a conserved deubiquitinase domain embedded within a pseudorabies virus structural protein, pUL36, is essential for initial neural invasion, but is subsequently dispensable for transmission within and between neurons of the mammalian nervous system. These findings indicate that the deubiquitinase contributes to neurovirulence by participating in a previously unrecognized initial step in neuroinvasion
Ultrafast terahertz-field-driven ionic response in ferroelectric BaTiO3
The dynamical processes associated with electric field manipulation of the polarization in a ferroelectric remain largely unknown but fundamentally determine the speed and functionality of ferroelectric materials and devices. Here we apply subpicosecond duration, single-cycle terahertz pulses as an ultrafast electric field bias to prototypical BaTiO[subscript 3] ferroelectric thin films with the atomic-scale response probed by femtosecond x-ray-scattering techniques. We show that electric fields applied perpendicular to the ferroelectric polarization drive large-amplitude displacements of the titanium atoms along the ferroelectric polarization axis, comparable to that of the built-in displacements associated with the intrinsic polarization and incoherent across unit cells. This effect is associated with a dynamic rotation of the ferroelectric polarization switching on and then off on picosecond time scales. These transient polarization modulations are followed by long-lived vibrational heating effects driven by resonant excitation of the ferroelectric soft mode, as reflected in changes in the c-axis tetragonality. The ultrafast structural characterization described here enables a direct comparison with first-principles-based molecular-dynamics simulations, with good agreement obtained
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