1,165 research outputs found
Regularities with random interactions in energy centroids defined by group symmetries
Regular structures generated by random interactions in energy centroids
defined over irreducible representations (irreps) of some of the group
symmetries of the interacting boson models IBM, IBM, IBM- and
IBM- are studied by deriving trace propagations equations for the
centroids. It is found that, with random interactions, the lowest and highest
group irreps in general carry most of the probability for the corresponding
centroids to be lowest in energy. This generalizes the result known earlier,
via numerical diagonalization, for the more complicated fixed spin ()
centroids where simple trace propagation is not possible.Comment: 18 pages, 3 figure
Random matrix ensemble with random two-body interactions in presence of a mean-field for spin one boson systems
For number of bosons, carrying spin (=1) degree of freedom, in
number of single particle orbitals, each triply degenerate, we
introduce and analyze embedded Gaussian orthogonal ensemble of random matrices
generated by random two-body interactions that are spin (S) scalar
[BEGOE(2)-]. The embedding algebra is with SO(3) generating spin . A method for constructing the ensembles
in fixed-(, ) space has been developed. Numerical calculations show that
the form of the fixed-(, ) density of states is close to Gaussian and
level fluctuations follow GOE. Propagation formulas for the fixed-(, )
space energy centroids and spectral variances are derived for a general one
plus two-body Hamiltonian preserving spin. In addition to these, we also
introduce two different pairing symmetry algebras in the space defined by
BEGOE(2)- and the structure of ground states is studied for each paring
symmetry.Comment: 22 pages, 6 figure
Constraining nuclear physics parameters with current and future COHERENT data
Motivated by the recent observation of coherent elastic neutrino-nucleus
scattering (CENS) at the COHERENT experiment, our goal is to explore its
potential in probing important nuclear structure parameters. We show that the
recent COHERENT data offers unique opportunities to investigate the neutron
nuclear form factor. Our present calculations are based on the deformed Shell
Model (DSM) method which leads to a better fit of the recent CENS data,
as compared to known phenomenological form factors such as the Helm-type,
symmetrized Fermi and Klein-Nystrand. The attainable sensitivities and the
prospects of improvement during the next phase of the COHERENT experiment are
also considered and analyzed in the framework of two upgrade scenarios.Comment: 13 pages, 5 figures, 2 tables; v2: minor corrections, version to
appear in PL
Half-lives and pre-supernova weak interaction rates for nuclei away from the stability line
A detailed model for the calculation of beta decay rates of the shell
nuclei for situations prevailing in pre-supernova and collapse phases of
evolution of the core of massive stars leading to supernova explosion has been
extended for electron-capture rates. It can also be used to determine the
half-lives of neutron-rich nuclei in the shell. The model uses an
averaged Gamow-Teller (GT) strength function. But it can also use the
experimental log ft values and GT strength function from reaction
studies wherever available. The calculated rate includes contributions from
each of the low-lying excited states of the mother including some specific
resonant states ("back resonance") having large GT matrix elements.Comment: 11 pages; Latex; no figs; version to appear in J. Phys.
O(12) limit and complete classification of symmetry schemes in proton-neutron interacting boson model
It is shown that the proton-neutron interacting boson model (pnIBM) admits
new symmetry limits with O(12) algebra which break F-spin but preserves the
quantum number M_F. The generators of O(12) are derived and the quantum number
`v' of O(12) for a given boson number N is determined by identifying the
corresponding quasi-spin algebra. The O(12) algebra generates two symmetry
schemes and for both of them, complete classification of the basis states and
typical spectra are given. With the O(12) algebra identified, complete
classification of pnIBM symmetry limits with good M_F is established.Comment: 22 pages, 1 figur
Health insurance coverage and maternal healthcare services utilization in Jordan: evidence from the 2017–18 Jordan demographic and health survey
Background
Despite the relationship between health insurance coverage and maternal healthcare services utilization, previous studies in Jordan on the use of maternal healthcare services have mainly focused on patterns and determinants of maternal healthcare services utilization in Jordan. Therefore, this study investigated the relationship between health insurance coverage and maternal healthcare services utilization in Jordan.
Methods
This study used secondary data published in 2017-18 Jordan Demographic and Health Survey on 4656 women of reproductive age (15–49 years). The independent variable was health insurance coverage and the outcome variable was maternal healthcare services utilization, measured through timing of first antenatal visit, four or more antenatal care visits, and skilled birth attendance. The data were analyzed using descriptive statistics and binary logistic regression.
Results
Out of the total number of women who participated in the study, 38.2% were not covered by health insurance. With maternal healthcare utilization, 12.5%, 23.2%, and 10.1% respectively, failed to make early first antenatal care visit, complete four or more antenatal care visits and have their delivery attended by a skilled worker. After controlling for the socio-demographic factors, health insurance coverage was associated with increased odds of early timing of first antenatal care visits and completion of four or more antenatal care visits (aOR = 1.33, p < 0.05, aOR = 1.25, p < 0.01, respectively). However, women who were covered by health insurance were less likely to use skilled birth attendance during delivery (aOR = 0.72 p < 0.001).
Conclusions
Jordanian women with health insurance coverage were more likely to have early first antenatal care visits and complete four or more antenatal care visits. However, they were less likely to have their delivery attended by a skilled professional. This study provides evidence that health insurance coverage has contributed to increased maternal healthcare services utilization, only in terms of number and timing of antenatal care visits in Jordan. It is recommended that policy makers in Jordan should strengthen the coverage of health insurance in the country, especially among women of reproductive age in order to enhance the use of maternal healthcare services in the country
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PprA Contributes to Deinococcus radiodurans Resistance to Nalidixic Acid, Genome Maintenance after DNA Damage and Interacts with Deinococcal Topoisomerases
PprA is known to contribute to Deinococcus radiodurans' remarkable capacity to survive a variety of genotoxic assaults. The molecular bases for PprA's role(s) in the maintenance of the damaged D. radiodurans genome are incompletely understood, but PprA is thought to promote D. radiodurans's capacity for DSB repair. PprA is found in a multiprotein DNA processing complex along with an ATP type DNA ligase, and the D. radiodurans toposiomerase IB (DraTopoIB) as well as other proteins. Here, we show that PprA is a key contributor to D. radiodurans resistance to nalidixic acid (Nal), an inhibitor of topoisomerase II. Growth of wild type D. radiodurans and a pprA mutant were similar in the absence of exogenous genotoxic insults; however, the pprA mutant exhibited marked growth delay and a higher frequency of anucleate cells following treatment with DNA-damaging agents. We show that PprA interacts with both DraTopoIB and the Gyrase A subunit (DraGyrA) in vivo and that purified PprA enhances DraTopoIB catalysed relaxation of supercoiled DNA. Thus, besides promoting DNA repair, our findings suggest that PprA also contributes to preserving the integrity of the D. radiodurans genome following DNA damage by interacting with DNA topoisomerases and by facilitating the actions of DraTopoIB
One plus two-body random matrix ensembles with parity: Density of states and parity ratios
One plus two-body embedded Gaussian orthogonal ensemble of random matrices
with parity [EGOE(1+2)-] generated by a random two-body interaction
(modeled by GOE in two particle spaces) in the presence of a mean-field, for
spinless identical fermion systems, is defined, generalizing the two-body
ensemble with parity analyzed by Papenbrock and Weidenm\"{u}ller [Phys. Rev. C
{\bf 78}, 054305 (2008)], in terms of two mixing parameters and a gap between
the positive and negative parity single particle (sp)
states. Numerical calculations are used to demonstrate, using realistic values
of the mixing parameters appropriate for some nuclei, that the EGOE(1+2)-
ensemble generates Gaussian form (with corrections) for fixed parity eigenvalue
densities (i.e. state densities). The random matrix model also generates many
features in parity ratios of state densities that are similar to those
predicted by a method based on the Fermi-gas model for nuclei. We have also
obtained, by applying the formulation due to Chang et al [Ann. Phys. (N.Y.)
{\bf 66}, 137 (1971)], a simple formula for the spectral variances defined over
fixed- spaces, where is the number of fermions in the +ve
parity sp states and is the number of fermions in the -ve parity sp
states. Similarly, using the binary correlation approximation, in the dilute
limit, we have derived expressions for the lowest two shape parameters. The
smoothed densities generated by the sum of fixed- Gaussians with
lowest two shape corrections describe the numerical results in many situations.
The model also generates preponderance of +ve parity ground states for small
values of the mixing parameters and this is a feature seen in nuclear shell
model results.Comment: 38 pages, 11 figures, 3 tables, enlarged and reorganized with
additional result
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