79 research outputs found
Deformations in N=14 isotones
Systematic analysis of deformations in neutron-rich N=14 isotones was done
based on the method of antisymmetrized molecular dynamics. The property of the
shape coexistence in Si, which is known to have the oblate ground state
and the prolate excited states, was successfully described. The results suggest
that the shape coexistence may occur also in neutron-rich N=14 nuclei as well
as Si. It was found that the oblate neutron shapes are favored because
of the spin-orbit force in most of N=14 isotones. moments and
transition strengths in the neutron-rich nuclei were discussed in relation to
the intrinsic deformations, and a possible difference between the proton and
neutron deformations in Ne was proposed.Comment: 13 pages, 7 figures, sumitted to Phys.Rev.
Effect of lifting COVID-19 restrictions on utilisation of primary care services in Nepal: a difference-in-differences analysis
INTRODUCTION: An increasing number of studies have reported disruptions in health service utilisation due to the COVID-19 pandemic and its associated restrictions. However, little is known about the effect of lifting COVID-19 restrictions on health service utilisation. The objective of this study was to estimate the effect of lifting COVID-19 restrictions on primary care service utilisation in Nepal. METHODS: Data on utilisation of 10 primary care services were extracted from the Health Management Information System across all health facilities in Nepal. We used a difference-in-differences design and linear fixed effects regressions to estimate the effect of lifting COVID-19 restrictions. The treatment group included palikas that had lifted restrictions in place from 17 August 2020 to 16 September 2020 (Bhadra 2077) and the control group included palikas that had maintained restrictions during that period. The pre-period included the 4 months of national lockdown from 24 March 2020 to 22 July 2020 (Chaitra 2076 to Ashar 2077). Models included month and palika fixed effects and controlled for COVID-19 incidence. RESULTS: We found that lifting COVID-19 restrictions was associated with an average increase per palika of 57.5 contraceptive users (95% CI 14.6 to 100.5), 15.6 antenatal care visits (95% CI 5.3 to 25.9) and 1.6 child pneumonia visits (95% CI 0.2 to 2.9). This corresponded to a 9.4% increase in contraceptive users, 34.2% increase in antenatal care visits and 15.6% increase in child pneumonia visits. Utilisation of most other primary care services also increased after lifting restrictions, but coefficients were not statistically significant. CONCLUSIONS: Despite the ongoing pandemic, lifting restrictions can lead to an increase in some primary care services. Our results point to a causal link between restrictions and health service utilisation and call for policy makers in low- and middle-income countries to carefully consider the trade-offs of strict lockdowns during future COVID-19 waves or future pandemics
Molecular dynamics approach: from chaotic to statistical properties of compound nuclei
Statistical aspects of the dynamics of chaotic scattering in the classical
model of -cluster nuclei are studied. It is found that the dynamics
governed by hyperbolic instabilities which results in an exponential decay of
the survival probability evolves to a limiting energy distribution whose
density develops the Boltzmann form. The angular distribution of the
corresponding decay products shows symmetry with respect to angle. Time
estimated for the compound nucleus formation ranges within the order of
s.Comment: 11 pages, LaTeX, non
Proton inelastic scattering to continuum studied with antisymmetrized molecular dynamics
Intermediate energy (p,px) reaction is studied with antisymmetrized
molecular dynamics (AMD) in the cases of Ni target with MeV
and C target with 200 and 90 MeV. Angular distributions for
various energies are shown to be reproduced well without any
adjustable parameter, which shows the reliability and usefulness of AMD in
describing light-ion reactions. Detailed analyses of the calculations are made
in the case of Ni target and following results are obtained: Two-step
contributions are found to be dominant in some large angle region and to be
indispensable for the reproduction of data. Furthermore the reproduction of
data in the large angle region \theta \agt 120^\circ for = 100 MeV
is shown to be due to three-step contributions. Angular distributions for
E_{p'} \agt 40 MeV are found to be insensitive to the choice of different
in-medium nucleon-nucleon cross sections and the reason of this
insensitivity is discussed in detail. On the other hand, the total reaction
cross section and the cross section of evaporated protons are found to be
sensitive to . In the course of the analyses of the calculations,
comparison is made with the distorted wave approach.Comment: 16 pages, 7 Postscript figure
Formula for proton-nucleus reaction cross section at intermediate energies and its application
We construct a formula for proton-nucleus total reaction cross section as a
function of the mass and neutron excess of the target nucleus and the proton
incident energy. We deduce the dependence of the cross section on the mass
number and the proton incident energy from a simple argument involving the
proton optical depth within the framework of a black sphere approximation of
nuclei, while we describe the neutron excess dependence by introducing the
density derivative of the symmetry energy, L, on the basis of a radius formula
constructed from macroscopic nuclear models. We find that the cross section
formula can reproduce the energy dependence of the cross section measured for
stable nuclei without introducing any adjustable energy dependent parameter. We
finally discuss whether or not the reaction cross section is affected by an
extremely low density tail of the neutron distribution for halo nuclei.Comment: 7 pages, 4 figures, added reference
Three-body dN interaction in the analysis of the 12C(pol_d,d') reaction at 270 MeV
We have measured the cross sections and analyzing powers Ay and Ayy for the
elastic and inelastic scattering of deuterons from the 0+(g.s.), 2+(4.44 MeV),
3-(9.64 MeV), 1+(12.71 MeV), and 2-(18.3 MeV) states in 12C at an incident
energy of 270 MeV. The data are compared with microscopic distorted-wave
impulse approximation calculations where the projectile-nucleon effective
interactionis taken from the three-nucleon t-matrix given by rigorous Faddeev
calculations presently available at intermediate energies. The agreement
between theory and data compares well with that for the (p,p') reactions at
comparable incident energies/nucleon.Comment: 17 pages, 3 Postscript figure
Nuclear Transparency to Intermediate-Energy Protons
Nuclear transparency in the (e,e'p) reaction for 135 < Tp < 800 MeV is
investigated using the distorted wave approximation. Calculations using
density-dependent effective interactions are compared with phenomenological
optical potentials. Nuclear transparency is well correlated with proton
absorption and neutron total cross sections. For Tp < 300 MeV there is
considerable sensitivity to the choice of optical model, with the empirical
effective interaction providing the best agreement with transparency data. For
Tp > 300 MeV there is much less difference between optical models, but the
calculations substantially underpredict transparency data and the discrepancy
increases with A. The differences between Glauber and optical model
calculations are related to their respective definitions of the semi-inclusive
cross section. By using a more inclusive summation over final states the
Glauber model emphasizes nucleon-nucleon inelasticity, whereas with a more
restrictive summation the optical model emphasizes nucleon-nucleus
inelasticity; experimental definitions of the semi-inclusive cross section lie
between these extremes.Comment: uuencoded gz-compressed tar file containing revtex and bbl files and
5 postscript figures, totalling 31 pages. Uses psfi
Toward a global description of the nucleus-nucleus interaction
Extensive systematization of theoretical and experimental nuclear densities
and of optical potential strengths exctracted from heavy-ion elastic scattering
data analyses at low and intermediate energies are presented.The
energy-dependence of the nuclear potential is accounted for within a model
based on the nonlocal nature of the interaction.The systematics indicate that
the heavy-ion nuclear potential can be described in a simple global way through
a double-folding shape,which basically depends only on the density of nucleons
of the partners in the collision.The poissibility of extracting information
about the nucleon-nucleon interaction from the heavy-ion potential is
investigated.Comment: 12 pages,12 figure
Molecular Dynamics for Fermions
The time-dependent variational principle for many-body trial states is used
to discuss the relation between the approaches of different molecular dynamics
models to describe indistinguishable fermions. Early attempts to include
effects of the Pauli principle by means of nonlocal potentials as well as more
recent models which work with antisymmetrized many-body states are reviewed
under these premises.
Keywords: Many-body theory; Fermion system; Molecular dynamics; Wave-packet
dynamics; Time-dependent variational principle; Statistical properties;
Canonical ensemble; Ergodicity; Time averagingComment: 97 pages, 13 postscript figures. To be published in July 2000 issue
of Reviews of Modern Physics. More information at http://www-aix.gsi.de/~fmd
Tracking health system performance in times of crisis using routine health data: lessons learned from a multicountry consortium
COVID-19 has prompted the use of readily available administrative data to track health system performance in times of crisis and to monitor disruptions in essential healthcare services. In this commentary we describe our experience working with these data and lessons learned across countries. Since April 2020, the Quality Evidence for Health System Transformation (QuEST) network has used administrative data and routine health information systems (RHIS) to assess health system performance during COVID-19 in Chile, Ethiopia, Ghana, Haiti, Lao People's Democratic Republic, Mexico, Nepal, South Africa, Republic of Korea and Thailand. We compiled a large set of indicators related to common health conditions for the purpose of multicountry comparisons. The study compiled 73 indicators. A total of 43% of the indicators compiled pertained to reproductive, maternal, newborn and child health (RMNCH). Only 12% of the indicators were related to hypertension, diabetes or cancer care. We also found few indicators related to mental health services and outcomes within these data systems. Moreover, 72% of the indicators compiled were related to volume of services delivered, 18% to health outcomes and only 10% to the quality of processes of care. While several datasets were complete or near-complete censuses of all health facilities in the country, others excluded some facility types or population groups. In some countries, RHIS did not capture services delivered through non-visit or nonconventional care during COVID-19, such as telemedicine. We propose the following recommendations to improve the analysis of administrative and RHIS data to track health system performance in times of crisis: ensure the scope of health conditions covered is aligned with the burden of disease, increase the number of indicators related to quality of care and health outcomes; incorporate data on nonconventional care such as telehealth; continue improving data quality and expand reporting from private sector facilities; move towards collecting patient-level data through electronic health records to facilitate quality-of-care assessment and equity analyses; implement more resilient and standardized health information technologies; reduce delays and loosen restrictions for researchers to access the data; complement routine data with patient-reported data; and employ mixed methods to better understand the underlying causes of service disruptions
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