2,763 research outputs found
Relativistic Hartree-Bogoliubov description of sizes and shapes of A=20 isobars
Ground-state properties of A = 20 nuclei (N, O, F,
Ne, Na, Mg) are described in the framework of Relativistic
Hartree-Bogoliubov (RHB) theory. The model uses the NL3 effective interaction
in the mean-field Lagrangian, and describes pairing correlations by the pairing
part of the finite range Gogny interaction D1S. Binding energies, quadrupole
deformations, nuclear matter radii, and differences in radii of proton and
neutron distributions are compared with recent experimental data.Comment: LaTeX 11 pages, 6 eps figs, submitted to Nucl. Phys.
Effects of Short Range Correlations on Ca Isotopes
The effect of Short Range Correlations (SRC) on Ca isotopes is studied using
a simple phenomenological model. Theoretical expressions for the charge
(proton) form factors, densities and moments of Ca nuclei are derived. The role
of SRC in reproducing the empirical data for the charge density differences is
examined. Their influence on the depletion of the nuclear Fermi surface is
studied and the fractional occupation probabilities of the shell model orbits
of Ca nuclei are calculated. The variation of SRC as function of the mass
number is also discussed.Comment: 11 pages (RevTex), 6 Postscript figures available upon request at
[email protected] Physical Review C in prin
Semimicroscopical description of the simplest photonuclear reactions accompanied by excitation of the giant dipole resonance in medium-heavy mass nuclei
A semimicroscopical approach is applied to describe photoabsorption and
partial photonucleon reactions accompanied by the excitation of the giant
dipole resonance (GDR). The approach is based on the continuum-RPA (CRPA) with
a phenomenological description for the spreading effect. The phenomenological
isoscalar part of the nuclear mean field, momentum-independent Landau-Migdal
particle-hole interaction, and separable momentum-dependent forces are used as
input quantities for the CRPA calculations. The experimental photoabsorption
and partial -reaction cross sections in the vicinity of the GDR are
satisfactorily described for Y, Ce and Pb target nuclei.
The total direct-neutron-decay branching ratio for the GDR in Ca and
Pb is also evaluated.Comment: 19 pages, 5 eps figure
Parity Mixed Doublets in A = 36 Nuclei
The -circular polarizations () and asymmetries
() of the parity forbidden M1 + E2 -decays: MeV) and MeV)
MeV) are investigated theoretically. We use the recently proposed
Warburton-Becker-Brown shell-model interaction. For the weak forces we discuss
comparatively different weak interaction models based on different assumptions
for evaluating the weak meson-hadron coupling constants. The results determine
a range of values from which we find the most probable values:
= for and = for .Comment: RevTeX, 17 pages; to appear in Phys. Rev.
Randomized controlled trial of intravenous antivenom versus placebo for latrodectism: the second redback antivenom evaluation (RAVE- II) study.
Objective: Latrodectism is the most important spider envenomation syndrome worldwide. There remains considerable controversy over antivenom treatment. We aimed to investigate whether antivenom resulted in resolution of pain and systemic effects in patients with latrodectism given standardized analgesia. Methods: In a multicentre randomized placebo-controlled trial of redback spider antivenom for latrodectism, 224 patients (>7yr) with a redback spider-bite and severe pain with or without systemic effects were randomized to receive normal saline (placebo) or antivenom, after receiving standardized analgesia. The primary outcome was a clinically significant reduction in pain 2 hours after trial medication compared to baseline. A second primary outcome for the subgroup with systemic features of envenomation was resolution of systemic features at 2 hours. Secondary outcomes were improved pain at 4 and 24 hours, resolution of systemic features at 4 hours, administration of opioid analgesics or unblinded antivenom after 2 hours and adverse reactions. Results: Two hours after treatment, 26/112 patients (23%) from the placebo arm had a clinically significant improvement in pain versus 38/112 (34%) from the antivenom arm (difference in favor of antivenom 10.7%;95%CI:â1.1% to +22.6%;p=0.10). Systemic 2 effects resolved after two hours in 9/41 patients (22%) in the placebo arm and 9/35 (26%) in the antivenom arm (difference 3.8%;95%CI:â15% to +23%;p=0.79). There was no significant difference in any secondary outcome between antivenom and placebo. Acute systemic hypersensitivity reactions occurred in 4/112 (3.6%) patients given antivenom. Conclusions: The addition of antivenom to standardized analgesia in patients with latrodectism, did not significantly improve pain or systemic effects.NHMRC 54522
Information-theoretic sensitivity analysis: a general method for credit assignment in complex networks
Most systems can be represented as networks that couple a series of nodes to each other via one or more edges, with typically unknown equations governing their quantitative behaviour. A major question then pertains to the importance of each of the elements that act as system inputs in determining the output(s). We show that any such system can be treated as a âcommunication channelâ for which the associations between inputs and outputs can be quantified via a decomposition of their mutual information into different components characterizing the main effect of individual inputs and their interactions. Unlike variance-based approaches, our novel methodology can easily accommodate correlated inputs
A dynamical chiral bag model
We study a dynamical chiral bag model, in which massless fermions are
confined within an impenetrable but movable bag coupled to meson fields. The
self-consistent motion of the bag is obtained by solving the equations of
motion exactly assuming spherical symmetry. When the bag interacts with an
external meson wave we find three different kinds of resonances: {\it
fermionic}, {\it geometric}, and -resonances. We discuss the
phenomenological implications of our results.Comment: Two columns, 11 pages, 9 figures. Submitted to Physical Review
Slater-Pauling Behavior of the Half-Ferromagnetic Full-Heusler Alloys
Using the full-potential screened Korringa-Kohn-Rostoker method we study the
full-Heusler alloys based on Co, Fe, Rh and Ru. We show that many of these
compounds show a half-metallic behavior, however in contrast to the
half-Heusler alloys the energy gap in the minority band is extremely small.
These full-Heusler compounds show a Slater-Pauling behavior and the total
spin-magnetic moment per unit cell (M_t) scales with the total number of
valence electrons (Z_t) following the rule: M_t=Z_t-24. We explain why the
spin-down band contains exactly 12 electrons using arguments based on the group
theory and show that this rule holds also for compounds with less than 24
valence electrons. Finally we discuss the deviations from this rule and the
differences compared to the half-Heusler alloys.Comment: 10 pages, 8 figures, revised figure 3, new text adde
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