4,001 research outputs found
Smoothed Affine Wigner Transform
We study a generalization of Husimi function in the context of wavelets. This
leads to a nonnegative density on phase-space for which we compute the
evolution equation corresponding to a Schr\"Aodinger equation
The confined-deconfined interface tension, wetting, and the spectrum of the transfer matrix
The reduced tension of the interface between the confined and
the deconfined phase of pure gauge theory is determined from numerical
simulations of the first transfer matrix eigenvalues. At we find
for . The interfaces show universal
behavior because the deconfined-deconfined interfaces are completely wet by the
confined phase. The critical exponents of complete wetting follow from the
analytic interface solutions of a -symmetric model in three
dimensions. We find numerical evidence that the confined-deconfined interface
is rough.Comment: Talk presented at the International Conference on Lattice Field
Theory, Lattice 92, to be published in the proceedings, 4 pages, 4 figures,
figures 2,3,4 appended as postscript files, figure 1 not available as a
postscript file but identical with figure 2 of Nucl. Phys. B372 (1992) 703,
special style file espcrc2.sty required (available from hep-lat), BUTP-92/4
Epigenetic modification of the oxytocin receptor gene is associated with emotion processing in the infant brain
The neural capacity to discriminate between emotions emerges early in development, though little is known about specific factors that contribute to variability in this vital skill during infancy. In adults, DNA methylation of the oxytocin receptor gene (OXTRm) is an epigenetic modification that is variable, predictive of gene expression, and has been linked to autism spectrum disorder and the neural response to social cues. It is unknown whether OXTRm is variable in infants, and whether it is predictive of early social function. Implementing a developmental neuroimaging epigenetics approach in a large sample of infants (N = 98), we examined whether OXTRm is associated with neural responses to emotional expressions. OXTRm was assessed at 5 months of age. At 7 months of age, infants viewed happy, angry, and fearful faces while functional near-infrared spectroscopy was recorded. We observed that OXTRm shows considerable variability among infants. Critically, infants with higher OXTRm show enhanced responses to anger and fear and attenuated responses to happiness in right inferior frontal cortex, a region implicated in emotion processing through action-perception coupling. Findings support models emphasizing oxytocin's role in modulating neural response to emotion and identify OXTRm as an epigenetic mark contributing to early brain function
The Interface Tension in Quenched QCD at the Critical Temperature
We present results for the confinement-deconfinement interface tension
of quenched QCD. They were obtained by applying Binder's
histogram method to lattices of size for and
L=8,10,12\mbox{ and }14 with for and otherwise. The
use of a multicanonical algorithm and cylindrical geometries have turned out to
be crucial for the numerical studies.Comment: (talk presented by B. Grossmann at Lattice 92), 4 pages with 5 figure
appended as encapsulated postscript files at the end, preprint HLRZ-92-7
The confined-deconfined Interface Tension and the Spectrum of the Transfer Matrix
The reduced tension of the interface between the confined and
the deconfined phase of pure gauge theory is related to the finite size
effects of the first transfer matrix eigenvalues. A lattice simulation of the
transfer matrix spectrum at the critical temperature yields
for . We found numerical evidence that
the deconfined-deconfined domain walls are completely wet by the confined
phase, and that the confined-deconfined interfaces are rough.Comment: 22 pages, LaTeX file with 4 ps figures included, HLRZ 92-47,
BUTP-92/3
Critical temperature of Bose-Einstein condensation in trapped atomic Bose-Fermi mixtures
We calculate the shift in the critical temperature of Bose-Einstein
condensation for a dilute Bose-Fermi mixture confined by a harmonic potential
to lowest order in both the Bose-Bose and Bose-Fermi coupling constants. The
relative importance of the effect on the critical temperature of the
boson-boson and boson-fermion interactions is investigated as a function of the
parameters of the mixture. The possible relevance of the shift of the
transition temperature in current experiments on trapped Bose-Fermi mixtures is
discussed.Comment: 15 pages, 2 figures, submitted to J. Phys.
Tuning the developing brain to emotional body expressions
Reading others’ emotional body expressions is an essential social skill. Adults readily recognize emotions from body movements. However, it is unclear when in development infants become sensitive to bodily expressed emotions. We examined event-related brain potentials (ERPs) in 4- and 8-month-old infants in response to point-light displays (PLDs) of happy and fearful body expressions presented in two orientations (upright and inverted). The ERP results revealed that 8-month-olds but not 4-month olds respond sensitively to the orientation and the emotion of the dynamic expressions. Specifically, 8-month-olds showed (i) an early (200–400 ms) orientation-sensitive positivity over frontal and central electrodes, and (ii) a late (700–1100 ms) emotion-sensitive positivity over temporal and parietal electrodes in the right hemisphere. These findings suggest that orientation-sensitive and emotion-sensitive brain processes, distinct in timing and topography, develop between 4 and 8 months of age
Variability in infants' functional brain network connectivity is associated with differences in affect and behavior
Variability in functional brain network connectivity has been linked to individual differences in cognitive, affective, and behavioral traits in adults. However, little is known about the developmental origins of such brain-behavior correlations. The current study examined functional brain network connectivity and its link to behavioral temperament in typically developing newborn and 1-month-old infants (M [age] = 25 days; N = 75) using functional near-infrared spectroscopy (fNIRS). Specifically, we measured long-range connectivity between cortical regions approximating fronto-parietal, default mode, and homologous-interhemispheric networks. Our results show that connectivity in these functional brain networks varies across infants and maps onto individual differences in behavioral temperament. Specifically, connectivity in the fronto-parietal network was positively associated with regulation and orienting behaviors, whereas connectivity in the default mode network showed the opposite effect on these behaviors. Our analysis also revealed a significant positive association between the homologous-interhemispheric network and infants' negative affect. The current results suggest that variability in long-range intra-hemispheric and cross-hemispheric functional connectivity between frontal, parietal, and temporal cortex is associated with individual differences in affect and behavior. These findings shed new light on the brain origins of individual differences in early-emerging behavioral traits and thus represent a viable novel approach for investigating developmental trajectories in typical and atypical neurodevelopment
First Order Phase Transition in a Reaction-Diffusion Model With Open Boundary: The Yang-Lee Theory Approach
A coagulation-decoagulation model is introduced on a chain of length L with
open boundary. The model consists of one species of particles which diffuse,
coagulate and decoagulate preferentially in the leftward direction. They are
also injected and extracted from the left boundary with different rates. We
will show that on a specific plane in the space of parameters, the steady state
weights can be calculated exactly using a matrix product method. The model
exhibits a first-order phase transition between a low-density and a
high-density phase. The density profile of the particles in each phase is
obtained both analytically and using the Monte Carlo Simulation. The two-point
density-density correlation function in each phase has also been calculated. By
applying the Yang-Lee theory we can predict the same phase diagram for the
model. This model is further evidence for the applicability of the Yang-Lee
theory in the non-equilibrium statistical mechanics context.Comment: 10 Pages, 3 Figures, To appear in Journal of Physics A: Mathematical
and Genera
On phases in weakly interacting finite Bose systems
We study precursors of thermal phase transitions in finite systems of
interacting Bose gases. For weakly repulsive interactions there is a phase
transition to the one-vortex state. The distribution of zeros of the partition
function indicates that this transition is first order, and the precursors of
the phase transition are already displayed in systems of a few dozen bosons.
Systems of this size do not exhibit new phases as more vortices are added to
the system.Comment: 7 pages, 2 figure
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