16,174 research outputs found
Asymmetric nuclear matter and neutron-skin in extended relativistic mean field model
The density dependence of the symmetry energy, instrumental in understanding
the behaviour of the asymmetric nuclear matter, is investigated within the
extended relativistic mean field (ERMF) model which includes the contributions
from the self and mixed interaction terms for the scalar-isoscalar (),
vector-isoscalar () and vector-isovector () mesons upto the
quartic order. Each of the 26 different parameterizations of the ERMF model
employed are compatible with the bulk properties of the finite nuclei. The
behaviour of the symmetry energy for several parameter sets are found to be
consistent with the empirical constraints on them as extracted from the
analyses of the isospin diffusion data. The neutron-skin thickness in the
Pb nucleus for these parameter sets of the ERMF model lie in the range
of fm which is in harmony with the ones predicted by the
Skyrme Hartree-Fock model. We also investigate the role of various mixed
interaction terms which are crucial for the density dependence of the symmetry
energy.Comment: 14 pages, 4 figures, Physical Review C (in press
Back to the Future: The Managed Care Revolution
The evolution to a managed care system did not achieve the complete, fundamental change in the health care delivery system that was envisioned by some of its early proponents. As the managed care movement evolved beyond the prepaid group practice model, it focused primarily on methods used to spread the cost of health care services
Verifying proofs in constant depth
In this paper we initiate the study of proof systems where verification of proofs proceeds by NC circuits. We investigate the question which languages admit proof systems in this very restricted model. Formulated alternatively, we ask which languages can be enumerated by NC functions. Our results show that the answer to this problem is not determined by the complexity of the language. On the one hand, we construct NC proof systems for a variety of languages ranging from regular to NP-complete. On the other hand, we show by combinatorial methods that even easy regular languages such as Exact-OR do not admit NC proof systems. We also present a general construction of proof systems for regular languages with strongly connected NFA's
Study of dominating parameters of high speed solar plasma streams in relation to cosmic ray and geomagnetic storms
The high speed solar wind streams observed near Earth are generally associated with the solar features, such as solar flares and coronal holes. Past studies of these streams from the two sources have revealed distinctly different effects on cosmic ray intensity, whereas the effect is similar for geomagnetic disturbances. Moreover, the effect of the magnitude of the high speed streams (V) and its rate of increase (dv/dt) has also been a subject of investigation to understand their relative contribution in producing geomagnetic disturbances. From the analysis of some of the fast streams presented here, it is difficult to predict, which one of the two (V, dv/dt) is more effective in producing geo-magnetic disturbances. Further, in most of the cases, no substantial decrease in cosmic ray intensity is observed
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