61,164 research outputs found
The BCS theory of q-deformed nucleon pairs - qBCS
We construct a coherent state of q-deformed zero coupled nucleon pairs
distributed in several single-particle orbits. Using a variational approach,
the set of equations of qBCS theory, to be solved self consistently for
occupation probabilities, gap parameter Delta, and the chemical potential
lambda, is obtained. Results for valence nucleons in nuclear degenerate sdg
major shell show that the strongly coupled zero angular momentum nucleon pairs
can be substituted by weakly coupled q-deformed zero angular momentum nucleon
pairs. A study of Sn isotopes reveals a well defined universe of (G, q) values,
for which qBCS converges. While the qBCS and BCS show similar results for Gap
parameter Delta in Sn isotopes, the ground state energies are lower in qBCS.
The pairing correlations in N nucleon system, increase with increasing q (for q
real).Comment: 8 pages, REVTEX, 3 eps figure
Software-defined networking: guidelines for experimentation and validation in large-scale real world scenarios
Part 1: IIVC WorkshopInternational audienceThis article thoroughly details large-scale real world experiments using Software-Defined Networking in the testbed setup. More precisely, it provides a description of the foundation technology behind these experiments, which in turn is focused around OpenFlow and on the OFELIA testbed. In this testbed preliminary experiments were performed in order to tune up settings and procedures, analysing the encountered problems and their respective solutions. A methodology consisting of five large-scale experiments is proposed in order to properly validate and improve the evaluation techniques used in OpenFlow scenarios
The strength of nuclear shell effects at N=126 in the r-process region
We have investigated nuclear shell effects across the magic number N=126 in
the region of the r-process path. Microscopic calculations have been performed
using the relativistic Hartree-Bogoliubov approach within the framework of the
RMF theory for isotopic chains of rare-earth nuclei in the r-process region.
The Lagrangian model NL-SV1 with the inclusion of the vector self-coupling of
omega meson has been employed. The RMF results show that the shell effects at
N=126 remain strong and exhibit only a slight reduction in the strength in
going from the r-process path to the neutron drip line. This is in striking
contrast to a systematic weakening of the shell effects at N=82 in the
r-process region predicted earlier in the similar approach. In comparison the
shell effects with microscopic-macroscopic mass formulae show a near constancy
of shell gaps leading to strong shell effects in the region of r-process path
to the drip line. A recent analysis of solar-system r-process abundances in a
prompt supernova explosion model using various mass formulae including the
recently introduced mass tables based upon HFB approach shows that whilst mass
formulae with weak shell effects at N=126 give rise to a spread and an
overproduction of nuclides near the third abundance peak at A~190, mass tables
with droplet models showing stronger shell effects are able to reproduce the
abundance features near the third peak appropriately. In comparison, several
analyses of the second r-process peak at A~130 have required weakened shell
effects at N=82. Our predictions in the RMF theory with NL-SV1, which exhibit
weaker shell effects at N=82 and stronger one at N=126 in the r-process region,
support the conjecture that a different nature of the shell effects at the
magic numbers may be at play in r-process nucleosynthesis of heavy nuclei.Comment: 14 pages, 8 figures; submitted to Physical Review C. Part of this
work was presented at Nuclear Physics in Astrophysics II, 20th International
Nuclear Physics Divisional Conference of the European Physical Society, at
Debrecen, Hungary, May 16-20, 200
Controle biologico do nematoide-das-galhas com bacteria Pasteuria penetrans.
bitstream/CPAC-2009/24830/1/bolpd_80.pd
Nuclear Breathing Mode in the Relativistic Mean Field Theory
The breathing-mode giant monopole resonance is studied within the framework
of the relativistic mean-field (RMF) theory. Using a broad range of parameter
sets, an analysis of constrained incompressibility and excitation energy of
isoscalar monopole states in finite nuclei is performed. It is shown that the
non-linear scalar self-interaction and the resulting surface properties
influence the breathing-mode considerably. It is observed that dynamical
surface properties respond differently in the RMF theory than in the Skyrme
approach. A comparison is made with the incompressibility derived from the
semi-infinite nuclear matter and with constrained nonrelativistic Skyrme
Hartree-Fock calculaions.Comment: Latex (12 pages) and 3 figures (available upon request) J. Phys. G
(in press
Comparative Statistical Analysis of Some Hydrobiological Parameters in Upstream and Downstream of River Asan
Today world is facing a number of challenges affecting the availability, accessibility, use and sustainability of its freshwater resources. Water is the most vital resource for living beings because there is no life without water as cellular activities never occur. Water is essential for the socio-economic development of human beings. Industrialization, urbanization, population explosion and green revolution have deteriorated the various sources of water. Keeping these points in mind, this study is designed to comparatively analyze the water quality of river Asan at upstream and downstream sites
- …
