544 research outputs found
Dissociating task difficulty from incongruence in face-voice emotion integration
In the everyday environment, affective information is conveyed by both the face and the voice. Studies have demonstrated that a concurrently presented voice can alter the way that an emotional face expression is perceived, and vice versa, leading to emotional conflict if the information in the two modalities is mismatched. Additionally, evidence suggests that incongruence of emotional valence activates cerebral networks involved in conflict monitoring and resolution. However, it is currently unclear whether this is due to task difficulty—that incongruent stimuli are harder to categorize—or simply to the detection of mismatching information in the two modalities. The aim of the present fMRI study was to examine the neurophysiological correlates of processing incongruent emotional information, independent of task difficulty. Subjects were scanned while judging the emotion of face-voice affective stimuli. Both the face and voice were parametrically morphed between anger and happiness and then paired in all audiovisual combinations, resulting in stimuli each defined by two separate values: the degree of incongruence between the face and voice, and the degree of clarity of the combined face-voice information. Due to the specific morphing procedure utilized, we hypothesized that the clarity value, rather than incongruence value, would better reflect task difficulty. Behavioral data revealed that participants integrated face and voice affective information, and that the clarity, as opposed to incongruence value correlated with categorization difficulty. Cerebrally, incongruence was more associated with activity in the superior temporal region, which emerged after task difficulty had been accounted for. Overall, our results suggest that activation in the superior temporal region in response to incongruent information cannot be explained simply by task difficulty, and may rather be due to detection of mismatching information between the two modalities
Radial molecular abundances and gas cooling in starless cores
Aims: We aim to simulate radial profiles of molecular abundances and the gas
temperature in cold and heavily shielded starless cores by combining chemical
and radiative transfer models. Methods: A determination of the dust temperature
in a modified Bonnor-Ebert sphere is used to calculate initial radial molecular
abundance profiles. The abundances of selected cooling molecules corresponding
to two different core ages are then extracted to determine the gas temperature
at two time steps. The calculation is repeated in an iterative process yielding
molecular abundances consistent with the gas temperature. Line emission
profiles for selected substances are calculated using simulated abundance
profiles. Results: The gas temperature is a function of time; the gas heats up
as the core gets older because the cooling molecules are depleted onto grain
surfaces. The contributions of the various cooling molecules to the total
cooling power change with time. Radial chemical abundance profiles are
non-trivial: different species present varying degrees of depletion and in some
cases inward-increasing abundances profiles, even at t > 10^5 years. Line
emission simulations indicate that cores of different ages can present
significantly different line emission profiles, depending on the tracer species
considered. Conclusions: Chemical abundances and the associated line cooling
power change as a function of time. Most chemical species are depleted onto
grain surfaces at densities exceeding ~10^5 cm^-3. Notable exceptions are NH_3
and N2H^+; the latter is largely undepleted even at n_H~10^6 cm-3. On the other
hand, chemical abundances are not significantly developed in regions of low gas
density even at t~10^5 years, revealed by inward-increasing abundance
gradients. The gas temperature can be significantly different from the dust
temperature; this may have implications on core stability.Comment: Accepted for publication in A&A, above abstract shortened to fit
arXiv forma
Towards precision medicine for hypertension: a review of genomic, epigenomic, and microbiomic effects on blood pressure in experimental rat models and humans
Compelling evidence for the inherited nature of essential hypertension has led to extensive research in rats and humans. Rats have served as the primary model for research on the genetics of hypertension resulting in identification of genomic regions that are causally associated with hypertension. In more recent times, genome-wide studies in humans have also begun to improve our understanding of the inheritance of polygenic forms of hypertension. Based on the chronological progression of research into the genetics of hypertension as the "structural backbone," this review catalogs and discusses the rat and human genetic elements mapped and implicated in blood pressure regulation. Furthermore, the knowledge gained from these genetic studies that provide evidence to suggest that much of the genetic influence on hypertension residing within noncoding elements of our DNA and operating through pervasive epistasis or gene-gene interactions is highlighted. Lastly, perspectives on current thinking that the more complex "triad" of the genome, epigenome, and the microbiome operating to influence the inheritance of hypertension, is documented. Overall, the collective knowledge gained from rats and humans is disappointing in the sense that major hypertension-causing genes as targets for clinical management of essential hypertension may not be a clinical reality. On the other hand, the realization that the polygenic nature of hypertension prevents any single locus from being a relevant clinical target for all humans directs future studies on the genetics of hypertension towards an individualized genomic approach
Accurate rate coefficients for models of interstellar gas-grain chemistry
The methodology for modeling grain-surface chemistry has been greatly
improved by taking into account the grain size and fluctuation effects.
However, the reaction rate coefficients currently used in all practical models
of gas-grain chemistry are inaccurate by a significant amount. We provide
expressions for these crucial rate coefficients that are both accurate and easy
to incorporate into gas-grain models.
We use exact results obtained in earlier work, where the reaction rate
coefficient was defined by a first-passage problem, which was solved using
random walk theory.
The approximate reaction rate coefficient presented here is easy to include
in all models of interstellar gas-grain chemistry. In contrast to the commonly
used expression, the results that it provides are in perfect agreement with
detailed kinetic Monte Carlo simulations. We also show the rate coefficient for
reactions involving multiple species.Comment: 4 pages, 2 figure
Perceptions of Facial Expressions of Emotion in Autism Spectrum Disorders: Reading the “minds eye” Using Reverse Correlation
One of the “primary social deficits” of Autism Spectrum Disorders (ASDs) is understanding the emotions of others, yet current literature is inconclusive as to whether individuals with ASD perceive basic facial expressions of emotion differently from typically developed (TD) individuals [Simmons, et al. 2009, Vision Research, 49, 12705-2739] and, if so, which specific emotions are confused
D-dimensional Ideal Quantum Gases in Potential
The paper is concerned with thermostatistics of both -dimensional Bose and
Fermi ideal gases in a confining potential of type . The
investigation is performed in the framework of the semiclassical approximation.
Some physical quantities for such systems are derived, like density of states,
density profiles and number of particles. Bose-Einstein condensation (BEC) is
discussed in the high and low temperature regimes.Comment: 13 pages, Late
Incorporation of stochastic chemistry on dust grains in the PDR code using moment equations
Unlike gas-phase reactions, chemical reactions taking place on interstellar
dust grain surfaces cannot always be modeled by rate equations. Due to the
small grain sizes and low flux,these reactions may exhibit large fluctuations
and thus require stochastic methods such as the moment equations.
We evaluate the formation rates of H2, HD and D2 molecules on dust grain
surfaces and their abundances in the gas phase under interstellar conditions.
We incorporate the moment equations into the Meudon PDR code and compare the
results with those obtained from the rate equations. We find that within the
experimental constraints on the energy barriers for diffusion and desorption
and for the density of adsorption sites on the grain surface, H2, HD and D2
molecules can be formed efficiently on dust grains.
Under a broad range of conditions, the moment equation results coincide with
those obtained from the rate equations. However, in a range of relatively high
grain temperatures, there are significant deviations. In this range, the rate
equations fail while the moment equations provide accurate results. The
incorporation of the moment equations into the PDR code can be extended to
other reactions taking place on grain surfaces
Reduced Hypoxia Risk in a Systemic Sclerosis Patient with Interstitial Lung Disease after Long-Term Pulmonary Rehabilitation
Pulmonary rehabilitation is effective for improving exercise capacity in patients with interstitial lung disease (ILD), and most programs last about 8 weeks. A 43-year-old male patient with systemic sclerosis and oxygen saturation (SpO2) declining because of severe ILD was hospitalized for treatment of chronic skin ulcers. During admission, he completed a 27-week walking exercise program with SpO2 monitoring. Consequently, continuous walking distance without severe hypoxia (SpO2 > 90%) increased from 60 m to 300 m after the program, although his six-minute walking distance remained the same. This suggests that walking exercise for several months may reduce the risk of hypoxia in patients with ILD, even though exercise capacity does not improve
On the Second Law of thermodynamics and the piston problem
The piston problem is investigated in the case where the length of the
cylinder is infinite (on both sides) and the ratio is a very small
parameter, where is the mass of one particle of the gaz and is the mass
of the piston. Introducing initial conditions such that the stochastic motion
of the piston remains in the average at the origin (no drift), it is shown that
the time evolution of the fluids, analytically derived from Liouville equation,
agrees with the Second Law of thermodynamics.
We thus have a non equilibrium microscopical model whose evolution can be
explicitly shown to obey the two laws of thermodynamics.Comment: 29 pages, 9 figures submitted to Journal of Statistical Physics
(2003
Molecular Clouds as Ensembles of Transient Cores
We construct models of molecular clouds that are considered as ensembles of
transient cores. Each core is assumed to develop in the background gas of the
cloud, grow to high density and decay into the background. The chemistry in
each core responds to the dynamical state of the gas and to the gas-dust
interaction. Ices are deposited on the dust grains in the core's dense phase,
and this material is returned to the gas as the core expands to low density.
The cores of the ensemble number typically one thousand and are placed randomly
in position within the cloud, and are assigned a random evolutionary phase.
The models are used to generate molecular line contour maps of a typical dark
cloud. These maps are found to represent extremely well the characteristic
features of observed maps of the dark cloud L673, which has been observed at
both low and high resolutions. The computed maps are found to exhibit the
general morphology of the observed maps, and to generate similar sizes of
emitting regions, molecular column densities, and the separations between peaks
of emissions of various molecular species. The models give insight into the
nature of molecular clouds and the dynamical processes occurring within them,
and significantly constrain dynamical and chemical processes in the
interstellar medium.Comment: 29 pages, 8 figures. Accepted for publication in Ap
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