4,350 research outputs found
Inversion improves the recognition of facial expression in thatcherized images
The Thatcher illusion provides a compelling example of the face inversion effect. However, the marked effect of inversion in the Thatcher illusion contrasts to other studies that report only a small effect of inversion on the recognition of facial expressions. To address this discrepancy, we compared the effects of inversion and thatcherization on the recognition of facial expressions. We found that inversion of normal faces caused only a small reduction in the recognition of facial expressions. In contrast, local inversion of facial features in upright thatcherized faces resulted in a much larger reduction in the recognition of facial expressions. Paradoxically, inversion of thatcherized faces caused a relative increase in the recognition of facial expressions. Together, these results suggest that different processes explain the effects of inversion on the recognition of facial expressions and on the perception of the Thatcher illusion. The grotesque perception of thatcherized images is based on a more orientation-sensitive representation of the face. In contrast, the recognition of facial expression is dependent on a more orientation-insensitive representation. A similar pattern of results was evident when only the mouth or eye region was visible. These findings demonstrate that a key component of the Thatcher illusion is to be found in orientation-specific encoding of the features of the face
Scale-free networks are not robust under neutral evolution
Recently it has been shown that a large variety of different networks have
power-law (scale-free) distributions of connectivities. We investigate the
robustness of such a distribution in discrete threshold networks under neutral
evolution. The guiding principle for this is robustness in the resulting
phenotype. The numerical results show that a power-law distribution is not
stable under such an evolution, and the network approaches a homogeneous form
where the overall distribution of connectivities is given by a Poisson
distribution.Comment: Submitted for publicatio
Pemanfaatan Radioisotop 32p Untuk Penandaan (Labelled Compound) Pada Nyamuk Aedes Aegypti
An Ae. aegypti mosquitoes labelling with Radioisotop 32P was performed at various dose application. The research conducted by Insitute of Vector and Reservoir Control Research and Development, Salatiga in collaboration with The National of Atomic Agency that aimed to know the effective dose and radioactivity disposal of the Radioisotop 32 P. The research used several doses: 0,3 µCi (micro currie); 0,5 µCi; and 0,7 µCi of each 25 gr larvaefood for 50 larvae with dry and wet radiation then observed the effect of radiation against larvae stadium and mosquitoes. The result shows that at 0,5 pCi isotop 32P dose application, Ae. aegypti mosquitoe can survive with 333,3 cps (currie per second) residual radioactivity and detected in 75 cm distance. The Radioisotop 32P can be used as Ae. aegypti mosquitoes labelling/marking
Tidal coupling of a Schwarzschild black hole and circularly orbiting moon
We describe the possibility of using LISA's gravitational-wave observations
to study, with high precision, the response of a massive central body to the
tidal gravitational pull of an orbiting, compact, small-mass object. Motivated
by this application, we use first-order perturbation theory to study tidal
coupling for an idealized case: a massive Schwarzschild black hole, tidally
perturbed by a much less massive moon in a distant, circular orbit. We
investigate the details of how the tidal deformation of the hole gives rise to
an induced quadrupole moment in the hole's external gravitational field at
large radii. In the limit that the moon is static, we find, in Schwarzschild
coordinates and Regge-Wheeler gauge, the surprising result that there is no
induced quadrupole moment. We show that this conclusion is gauge dependent and
that the static, induced quadrupole moment for a black hole is inherently
ambiguous. For the orbiting moon and the central Schwarzschild hole, we find
(in agreement with a recent result of Poisson) a time-varying induced
quadrupole moment that is proportional to the time derivative of the moon's
tidal field. As a partial analog of a result derived long ago by Hartle for a
spinning hole and a stationary distant companion, we show that the orbiting
moon's tidal field induces a tidal bulge on the hole's horizon, and that the
rate of change of the horizon shape leads the perturbing tidal field at the
horizon by a small angle.Comment: 14 pages, 0 figures, submitted to Phys. Rev.
Atomic Collapse and Quasi-Rydberg States in Graphene
Charge impurities in graphene can host an infinite family of Rydberg-like
resonance states of massless Dirac particles. These states, appearing for
supercritical charge, are described by Bohr-Sommerfeld quantization of
collapsing classical trajectories that descend on point charge, in analogy to
Rydberg states relation with planetary orbits. We argue that divalent and
trivalent charge impurities in graphene is an ideal system for realization of
this atomic collapse regime. Strong coupling of these states to the Dirac
continuum via Klein tunneling leads to striking resonance effects with direct
signatures in transport, local properties and enhancement of the Kondo effect.Comment: 5 pages, 4 figure
Fluctuations of the Condensate in Ideal and Interacting Bose Gases
We investigate the fluctuations of the condensate in the ideal and weakly
interacting Bose gases confined in a box of volume V within canonical ensemble.
Canonical ensemble is developed to describe the behavior of the fluctuations
when different methods of approximation to the weakly interacting Bose gases
are used. Research shows that the fluctuations of the condensate exhibit
anomalous behavior for the interacting Bose gas confined in a box.Comment: RevTex, 4 Figs,E-mail:[email protected], corrected typo
Exact results for `bouncing' Gaussian wave packets
We consider time-dependent Gaussian wave packet solutions of the Schrodinger
equation (with arbitrary initial central position, x_0, and momentum, p_0, for
an otherwise free-particle, but with an infinite wall at x=0, so-called
bouncing wave packets. We show how difference or mirror solutions of the form
psi(x,t)-psi(-x,t) can, in this case, be normalized exactly, allowing for the
evaluation of a number of time-dependent expectation values and other
quantities in closed form. For example, we calculate _t explicitly which
illustrates how the free-particle kinetic (and hence total) energy is affected
by the presence of the distant boundary. We also discuss the time dependence of
the expectation values of position, _t, and momentum, _t, and their
relation to the impulsive force during the `collision' with the wall. Finally,
the x_0,p_0 --> 0 limit is shown to reduce to a special case of a non-standard
free-particle Gaussian solution. The addition of this example to the literature
then expands on the relatively small number of Gaussian solutions to quantum
mechanical problems with familiar classical analogs (free particle, uniform
acceleration, harmonic oscillator, unstable oscillator, and uniform magnetic
field) available in closed form.Comment: 14 pages, 1 embedded .eps figur
Spin projected unrestricted Hartree-Fock ground states for harmonic quantum dots
We report results for the ground state energies and wave functions obtained
by projecting spatially unrestricted Hartree Fock states to eigenstates of the
total spin and the angular momentum for harmonic quantum dots with
interacting electrons including a magnetic field states with the correct
spatial and spin symmetries have lower energies than those obtained by the
unrestricted method. The chemical potential as a function of a perpendicular
magnetic field is obtained. Signature of an intrinsic spin blockade effect is
found.Comment: 12 pages, 5 tables, 10 figures, submitted to Phys. Rev.
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