29,108 research outputs found
Breathing-mode measurements in Sn isotopes and isospin dependence of nuclear incompressibility
T. Li {\it et al.}[Phys. Rev. C {\bf 81}, 034309 (2010)] have analyzed their
measured breathing-mode energies of some tin isotopes in terms of a first-order
leptodermous expansion, and find for the symmetry-incompressibility coefficient
the value of -550 100 MeV. Removing an approximation that they
made, we find that the first-order estimate of shifts to -661
144 MeV. However, taking into account higher-order terms in the leptodermous
expansion shows that the data are compatible with the significantly lower
magnitudes indicated by both another experiment and some theoretical estimates.Comment: 6 pages, 1 figur
Pairing: from atomic nuclei to neutron-star crusts
Nuclear pairing is studied both in atomic nuclei and in neutron-star crusts
in the unified framework of the energy-density functional theory using
generalized Skyrme functionals complemented with a local pairing functional
obtained from many-body calculations in homogeneous nuclear matter using
realistic forces.Comment: 16 pages, 3 figures. Contribution for the book "50 years of nuclear
BCS", edited by R.A. Broglia and V. Zelevinsk
Superfluidity and entrainment in neutron-star crusts
Despite the absence of viscous drag, the neutron superfluid permeating the
inner crust of a neutron star can still be strongly coupled to nuclei due to
non-dissipative entrainment effects. Neutron superfluidity and entrainment have
been systematically studied in all regions of the inner crust of a cold
non-accreting neutron star in the framework of the band theory of solids. It is
shown that in the intermediate layers of the inner crust a large fraction of
"free" neutrons are actually entrained by the crust. The results suggest that a
revision of the interpretation of many observable astrophysical phenomena might
be necessary.Comment: 4 pages, to appear in the proceedings of the ERPM conference, Zielona
Gora, Poland, April 201
Measuring micro-organism gas production
Transducer, which senses pressure buildup, is easy to assemble and use, and rate of gas produced can be measured automatically and accurately. Method can be used in research, in clinical laboratories, and for environmental pollution studies because of its ability to detect and quantify rapidly the number of gas-producing microorganisms in water, beverages, and clinical samples
Quantifying the Socio-Economic Benefits of Reducing Industrial Dietary Trans Fats: Modelling Study.
BACKGROUND: Coronary Heart Disease (CHD) remains a leading cause of UK mortality, generating a large and unequal burden of disease. Dietary trans fatty acids (TFA) represent a powerful CHD risk factor, yet to be addressed in the UK (approximately 1% daily energy) as successfully as in other nations. Potential outcomes of such measures, including effects upon health inequalities, have not been well quantified. We modelled the potential effects of specific reductions in TFA intake on CHD mortality, CHD related admissions, and effects upon socioeconomic inequalities. METHODS & RESULTS: We extended the previously validated IMPACTsec model, to estimate the potential effects of reductions (0.5% & 1% reductions in daily energy) in TFA intake in England and Wales, stratified by age, sex and socioeconomic circumstances. We estimated reductions in expected CHD deaths in 2030 attributable to these two specific reductions. Output measures were deaths prevented or postponed, life years gained and hospital admissions. A 1% reduction in TFA intake energy intake would generate approximately 3,900 (95% confidence interval (CI) 3,300-4,500) fewer deaths, 10,000 (8,800-10,300) (7% total) fewer hospital admissions and 37,000 (30,100-44,700) life years gained. This would also reduce health inequalities, preventing five times as many deaths and gaining six times as many life years in the most deprived quintile compared with the most affluent. A more modest reduction (0.5%) would still yield substantial health gains. CONCLUSIONS: Reducing intake of industrial TFA could substantially decrease CHD mortality and hospital admissions, and gain tens of thousands of life years. Crucially, this policy could also reduce health inequalities. UK strategies should therefore aim to minimise industrial TFA intake
Control of Raman Lasing in the Nonimpulsive Regime
We explore coherent control of stimulated Raman scattering in the
nonimpulsive regime. Optical pulse shaping of the coherent pump field leads to
control over the stimulated Raman output. A model of the control mechanism is
investigated.Comment: 4 pages, 5 figure
Structure of neutron stars with unified equations of state
We present a set of three unified equations of states (EoSs) based on the
nuclear energy-density functional (EDF) theory.These EoSs are based on
generalized Skyrme forces fitted to essentially all experimental atomic mass
data and constrained to reproduce various properties of infinite nuclear matter
as obtained from many-body calculations using realistic two- and three-body
interactions. The structure of cold isolated neutron stars is discussed in
connection with some astrophysical observations.Comment: 4 pages, to appear in the proceedings of the ERPM conference, Zielona
Gora, Poland, April 201
Symmetry energy: nuclear masses and neutron stars
We describe the main features of our most recent Hartree-Fock-Bogoliubov
nuclear mass models, based on 16-parameter generalized Skyrme forces. They have
been fitted to the data of the 2012 Atomic Mass Evaluation, and favour a value
of 30 MeV for the symmetry coefficient J, the corresponding root-mean square
deviation being 0.549 MeV. We find that this conclusion is compatible with
measurements of neutron-skin thickness. By constraining the underlying
interactions to fit various equations of state of neutron matter calculated
{\it ab initio} our models are well adapted to a realistic and unified
treatment of all regions of neutron stars. We use our models to calculate the
composition, the equation of state, the mass-radius relation and the maximum
mass. Comparison with observations of neutron stars again favours a value of J
= 30 MeV.Comment: 10 pages, 9 figures, to appear in EPJA special volume on symmetry
energ
Further explorations of Skyrme-Hartree-Fock-Bogoliubov mass formulas. III: Role of particle-number projection
Starting from HFB-6, we have constructed a new mass table, referred to as
HFB-8, including all the 9200 nuclei lying between the two drip lines over the
range of Z and N > 6 and Z < 122. It differs from HFB-6 in that the wave
function is projected on the exact particle number. Like HFB-6, the isoscalar
effective mass is constrained to the value 0.80 M and the pairing is density
independent. The rms errors of the mass-data fit is 0.635 MeV, i.e. better than
almost all our previous HFB mass formulas. The extrapolations of this new mass
formula out to the drip lines do not differ significantly from the previous
HFB-6 mass formula.Comment: 9 pages, 7 figures, accepted for publication in Phys. Rev.
The Cluster Distribution as a Test of Dark Matter Models. IV: Topology and Geometry
We study the geometry and topology of the large-scale structure traced by
galaxy clusters in numerical simulations of a box of side 320 Mpc, and
compare them with available data on real clusters. The simulations we use are
generated by the Zel'dovich approximation, using the same methods as we have
used in the first three papers in this series. We consider the following models
to see if there are measurable differences in the topology and geometry of the
superclustering they produce: (i) the standard CDM model (SCDM); (ii) a CDM
model with (OCDM); (iii) a CDM model with a `tilted' power
spectrum having (TCDM); (iv) a CDM model with a very low Hubble
constant, (LOWH); (v) a model with mixed CDM and HDM (CHDM); (vi) a
flat low-density CDM model with and a non-zero cosmological
term (CDM). We analyse these models using a variety of
statistical tests based on the analysis of: (i) the Euler-Poincar\'{e}
characteristic; (ii) percolation properties; (iii) the Minimal Spanning Tree
construction. Taking all these tests together we find that the best fitting
model is CDM and, indeed, the others do not appear to be consistent
with the data. Our results demonstrate that despite their biased and extremely
sparse sampling of the cosmological density field, it is possible to use
clusters to probe subtle statistical diagnostics of models which go far beyond
the low-order correlation functions usually applied to study superclustering.Comment: 17 pages, 7 postscript figures, uses mn.sty, MNRAS in pres
- …