15 research outputs found
In medium T-matrix for superfluid nuclear matter
We study a generalized ladder resummation in the superfluid phase of the
nuclear matter. The approach is based on a conserving generalization of the
usual T-matrix approximation including also anomalous self-energies and
propagators. The approximation here discussed is a generalization of the usual
mean-field BCS approach and of the in medium T-matrix approximation in the
normal phase. The numerical results in this work are obtained in the
quasi-particle approximation. Properties of the resulting self-energy,
superfluid gap and spectral functions are studied.Comment: 38 pages, 19 figures, Introduction rewritten, Refs. adde
Computing gravitational waves from slightly nonspherical stellar collapse to black hole: Odd-parity perturbation
Nonspherical stellar collapse to a black hole is one of the most promising
gravitational wave sources for gravitational wave detectors. We numerically
study gravitational waves from a slightly nonspherical stellar collapse to a
black hole in linearized Einstein theory. We adopt a spherically collapsing
star as the zeroth-order solution and gravitational waves are computed using
perturbation theory on the spherical background. In this paper we focus on the
perturbation of odd-parity modes. Using the polytropic equations of state with
polytropic indices and 3, we qualitatively study gravitational waves
emitted during the collapse of neutron stars and supermassive stars to black
holes from a marginally stable equilibrium configuration. Since the matter
perturbation profiles can be chosen arbitrarily, we provide a few types for
them. For , the gravitational waveforms are mainly characterized by a
black hole quasinormal mode ringing, irrespective of perturbation profiles
given initially. However, for , the waveforms depend strongly on the
initial perturbation profiles. In other words, the gravitational waveforms
strongly depend on the stellar configuration and, in turn, on the ad hoc choice
of the functional form of the perturbation in the case of supermassive stars.Comment: 31 pages, accepted for publication in Phys. Rev. D, typos and minor
errors correcte
Dynamic Evolution of a Quasi-Spherical General Polytropic Magnetofluid with Self-Gravity
In various astrophysical contexts, we analyze self-similar behaviours of
magnetohydrodynamic (MHD) evolution of a quasi-spherical polytropic magnetized
gas under self-gravity with the specific entropy conserved along streamlines.
In particular, this MHD model analysis frees the scaling parameter in the
conventional polytropic self-similar transformation from the constraint of
with being the polytropic index and therefore
substantially generalizes earlier analysis results on polytropic gas dynamics
that has a constant specific entropy everywhere in space at all time. On the
basis of the self-similar nonlinear MHD ordinary differential equations, we
examine behaviours of the magnetosonic critical curves, the MHD shock
conditions, and various asymptotic solutions. We then construct global
semi-complete self-similar MHD solutions using a combination of analytical and
numerical means and indicate plausible astrophysical applications of these
magnetized flow solutions with or without MHD shocks.Comment: 21 pages, 7 figures, accepted for publication in APS
Measurement of Family Management in Families of Individuals With Down Syndrome: A Cross-Cultural Investigation
Down syndrome (DS) is the most common genetic cause of intellectual disability worldwide. The purpose of this analysis was to determine the internal consistency reliability of eight language versions of the Family Management Measure (FaMM) and compare family management of DS across cultures. A total of 2,740 parents of individuals with DS from 11 countries completed the FaMM. The analysis provided evidence of internal consistency reliability exceeding.70 for four of six FaMM scales for the entire sample. Across countries, there was a pattern of positive family management. Cross-cultural comparisons revealed parents from Brazil, Spain, and the United States had the most positive family management and respondents from Ireland, Italy, Japan, and Korea had the least positive. The rankings were mixed for the four remaining countries. These findings provide evidence of overall strong internal consistency reliability of the FaMM. More cross-cultural research is needed to understand how social determinants of health influence family management in families of individuals with DS
Measurement of family management in families of individuals with down syndrome: a cross-cultural investigation
Down syndrome (DS) is the most common genetic cause of intellectual disability worldwide. The purpose of this analysis was to determine the internal consistency reliability of eight language versions of the Family Management Measure (FaMM) and compare family management of DS across cultures. A total of 2,740 parents of individuals with DS from 11 countries completed the FaMM. The analysis provided evidence of internal consistency reliability exceeding .70 for four of six FaMM scales for the entire sample. Across countries, there was a pattern of positive family management. Cross-cultural comparisons revealed parents from Brazil, Spain, and the United States had the most positive family management and respondents from Ireland, Italy, Japan, and Korea had the least positive. The rankings were mixed for the four remaining countries. These findings provide evidence of overall strong internal consistency reliability of the FaMM. More cross-cultural research is needed to understand how social determinants of health influence family management in families of individuals with DS.Education and Child Studie
Matter in Strong Magnetic Fields
The properties of matter are significantly modified by strong magnetic
fields, Gauss (), as are typically
found on the surfaces of neutron stars. In such strong magnetic fields, the
Coulomb force on an electron acts as a small perturbation compared to the
magnetic force. The strong field condition can also be mimicked in laboratory
semiconductors. Because of the strong magnetic confinement of electrons
perpendicular to the field, atoms attain a much greater binding energy compared
to the zero-field case, and various other bound states become possible,
including molecular chains and three-dimensional condensed matter. This article
reviews the electronic structure of atoms, molecules and bulk matter, as well
as the thermodynamic properties of dense plasma, in strong magnetic fields,
. The focus is on the basic physical pictures and
approximate scaling relations, although various theoretical approaches and
numerical results are also discussed. For the neutron star surface composed of
light elements such as hydrogen or helium, the outermost layer constitutes a
nondegenerate, partially ionized Coulomb plasma if , and may be in
the form of a condensed liquid if the magnetic field is stronger (and
temperature K). For the iron surface, the outermost layer of the
neutron star can be in a gaseous or a condensed phase depending on the cohesive
property of the iron condensate.Comment: 45 pages with 9 figures. Many small additions/changes. Accepted for
publication in Rev. Mod. Phy
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The use of particle tracks in problem analysis
The visualization of the microscopic phenomena in a Monte Carlo simulation can improve the understanding of the problem and provide an important check on the model definition and execution. The paths, or tracks, of a sample of the Monte Carlo particles show how fission source neutrons migrate from one generation to another. The location of fission source neutrons and interactions can be shown by event markers. This new visualization is available for the Monte Carlo n-particle code MCNP due to the addition of fission source neutrons, tagged by cycle number, to the particle track (PTRAC) data. We report here on the use of this and similar information for the analysis and illustration of criticality calculations
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AVATAR{trademark} (Automatic Variance And Time of Analysis Reduction), accessed through the graphical user interface application, Justine{trademark}, is a superset of MCNP{trademark} that automatically invokes THREEDANT{trademark} for a three-dimensional deterministic adjoint calculation on a mesh independent of the Monte Carlo geometry, calculates weight windows, and runs MCNP. Computational efficiency increases by a factor of 2 to 5 for a three-detector oil well logging tool model. Human efficiency increases dramatically, since AVATAR eliminates the need for deep intuition and hours of tedious handwork