7,129 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
Numerical approach for retention characteristics of double floating-gate memories
We report on a numerical investigation in which memory characteristics of
double floating-gate (DFG) structure were compared to those of the conventional
single floating-gate structure, including an interference effect between two
cells. We found that the advantage of the DFG structure is its longer retention
time and the disadvantage is its smaller threshold voltage shift. We also
provide an analytical form of charging energy including the interference
effect.Comment: 4 pages, 4 figure
Dynamic Modes of Microcapsules in Steady Shear Flow: Effects of Bending and Shear Elasticities
The dynamics of microcapsules in steady shear flow was studied using a
theoretical approach based on three variables: The Taylor deformation parameter
, the inclination angle , and the phase angle of
the membrane rotation. It is found that the dynamic phase diagram shows a
remarkable change with an increase in the ratio of the membrane shear and
bending elasticities. A fluid vesicle (no shear elasticity) exhibits three
dynamic modes: (i) Tank-treading (TT) at low viscosity of
internal fluid ( and relaxes to constant values), (ii)
Tumbling (TB) at high ( rotates), and (iii) Swinging
(SW) at middle and high shear rate (
oscillates). All of three modes are accompanied by a membrane ()
rotation. For microcapsules with low shear elasticity, the TB phase with no
rotation and the coexistence phase of SW and TB motions are induced by
the energy barrier of rotation. Synchronization of rotation with
TB rotation or SW oscillation occurs with integer ratios of rotational
frequencies. At high shear elasticity, where a saddle point in the energy
potential disappears, intermediate phases vanish, and either or
rotation occurs. This phase behavior agrees with recent simulation results of
microcapsules with low bending elasticity.Comment: 11 pages, 14 figure
Robustly Unstable Eigenmodes of the Magnetoshearing Instability in Accretion Disk
The stability of nonaxisymmetric perturbations in differentially rotating
astrophysical accretion disks is analyzed by fully incorporating the properties
of shear flows. We verify the presence of discrete unstable eigenmodes with
complex and pure imaginary eigenvalues, without any artificial disk edge
boundaries, unlike Ogilvie & Pringle(1996)'s claim. By developing the
mathematical theory of a non-self-adjoint system, we investigate the nonlocal
behavior of eigenmodes in the vicinity of Alfven singularities at
omega_D=omega_A, where omega_D is the Doppler-shifted wave frequency and
omega_A=k_// v_A is the Alfven frequency. The structure of the spectrum of
discrete eigenmodes is discussed and the magnetic field and wavenumber
dependence of the growth rate are obtained. Exponentially growing modes are
present even in a region where the local dispersion relation theory claims to
have stable eigenvalues. The velocity field created by an eigenmode is
obtained, which explains the anomalous angular momentum transport in the
nonlinear stage of this stability.Comment: 11pages, 11figures, to be published in ApJ. For associated eps files,
see http://dino.ph.utexas.edu/~knoguchi
Reversibility of Red blood Cell deformation
The ability of cells to undergo reversible shape changes is often crucial to
their survival. For Red Blood Cells (RBCs), irreversible alteration of the cell
shape and flexibility often causes anemia. Here we show theoretically that RBCs
may react irreversibly to mechanical perturbations because of tensile stress in
their cytoskeleton. The transient polymerization of protein fibers inside the
cell seen in sickle cell anemia or a transient external force can trigger the
formation of a cytoskeleton-free membrane protrusion of micrometer dimensions.
The complex relaxation kinetics of the cell shape is shown to be responsible
for selecting the final state once the perturbation is removed, thereby
controlling the reversibility of the deformation. In some case, tubular
protrusion are expected to relax via a peculiar "pearling instability".Comment: 4 pages, 3 figure
The Nuclear Activity of the Galaxies in the Hickson Compact Groups
In order to investigate the nuclear activity of galaxies residing in compact
groups of galaxies, we present results of our optical spectroscopic program
made at Okayama Astrophysical Observatory. We have performed optical
spectroscopy of 69 galaxies which belong to 31 Hickson Compact Groups (HCGs) of
Galaxies. Among them, three galaxies have discordant redshifts. Further,
spectral quality is too poor to classify other three galaxies. Therefore, we
describe our results for the remaining 63 galaxies.
Our main results are summarized below. (1) We have found in our sample; 28
AGN, 16 HII nuclei, and 19 normal galaxies which show no emission line. We used
this HCG sample for statistical analyses. (2) Comparing the frequency
distributions of activity types between the HCGs and the field galaxies whose
data are taken from Ho, Filippenko, & Sargent (382 field galaxies), we find
that the frequency of HII nuclei in the HCGs is significantly less than that in
the field. However, this difference may be due to selection bias that our HCG
sample contains more early-type galaxies than the field, because it is known
that HII nuclei are rarer in early-type galaxies than in later ones. (3)
Applying correction this morphological bias to the HCG sample, we find that
there is no statistically significant difference in the frequency of occurrence
of emission-line galaxies between the HCGs and the field. This implies that the
dense galaxy environment in the HCGs does not affect triggering both the AGN
activity and the nuclear starburst. We discuss some implications on the nuclear
activity in the HCG galaxies.Comment: 33 pages (3 aasms4 LaTeX files), 5 figures (5 Postscript files:
excluded Figure 1), Accepted for publication in The Astronomical Journa
Solvent-free coarse-grained lipid model for large-scale simulations
A coarse-grained molecular model, which consists of a spherical particle and
an orientation vector, is proposed to simulate lipid membrane on a large length
scale. The solvent is implicitly represented by an effective attractive
interaction between particles. A bilayer structure is formed by
orientation-dependent (tilt and bending) potentials. In this model, the
membrane properties (bending rigidity, line tension of membrane edge, area
compression modulus, lateral diffusion coefficient, and flip-flop rate) can be
varied over broad ranges. The stability of the bilayer membrane is investigated
via droplet-vesicle transition. The rupture of the bilayer and worm-like
micelle formation can be induced by an increase in the spontaneous curvature of
the monolayer membrane.Comment: 13 pages, 19 figure
Analytic and rational sections of relative semi-abelian varieties
The hyperbolicity statements for subvarieties and complement of hypersurfaces in abelian varieties admit arithmetic analogues, due to Faltings, Ann. Math. 133 (1991) (and for the semi-abelian case, Vojta, Invent. Math. 126 (1996); Amer. J. Math. 121 (1999)). In Atti Accad. Naz. Lincei Rend. Lincei Mat. Appl. 29 (2018) by the second author, an analogy between the analytic and arithmetic theories was shown to hold also at proof level, namely in a proof of Raynaud’s theorem (Manin–Mumford Conjecture). The first aim of this paper is to extend to the relative setting the above mentioned hyperbolicity results. We shall be concerned with analytic sections of a relative (semi-)abelian scheme A → B over an affine algebraic curve B. These sections form a group; while the group of the rational sections (the Mordell–Weil group) has been widely studied, little investigation has been pursued so far on the group of the analytic sections. We take the opportunity of developing some basic structure of this apparently new theory, defining a notion of height or order functions for the analytic sections, by means of Nevanlinna theory
The Advantage of Increased Resolution in the Study of Quasar Absorption Systems
We compare a new R = 120,000 spectrum of PG1634+706 (z_QSO = 1.337,m_V =
14.9) obtained with the HDS instrument on Subaru to a R = 45, 000 spectrum
obtained previously with HIRES/Keck. In the strong MgII system at z = 0.9902
and the multiple cloud, weak MgII system at z = 1.0414, we find that at the
higher resolution, additional components are resolved in a blended profile. We
find that two single-cloud weak MgII absorbers were already resolved at R =
45,000, to have b = 2 - 4 km/s. The narrowest line that we measure in the R =
120, 000 spectrum is a component of the Galactic NaI absorption, with b =
0.90+/-0.20 km/s. We discuss expectations of similarly narrow lines in various
applications, including studies of DLAs, the MgI phases of strong MgII
absorbers, and high velocity clouds. By applying Voigt profile fitting to
synthetic lines, we compare the consistency with which line profile parameters
can be accurately recovered at R = 45,000 and R = 120,000. We estimate the
improvement gained from superhigh resolution in resolving narrowly separated
velocity components in absorption profiles. We also explore the influence of
isotope line shifts and hyperfine splitting in measurements of line profile
parameters, and the spectral resolution needed to identify these effects. Super
high resolution spectra of quasars, which will be routinely possible with
20-meter class telescopes, will lead to greater sensitivity for absorption line
surveys, and to determination of more accurate physical conditions for cold
phases of gas in various environments.Comment: To appear in AJ. Paper with better resolution images available at
http://www.astro.psu.edu/users/anand/superhigh.AJ.pd
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