4,367 research outputs found
Bandverbindungen der DornfortsÀtze der WirbelsÀule
In the cervical region the fibres of the interspinous and nuchal ligaments pass in an anteroc
ranial direction: they act against diminishing of the cervical lordosis. In the thoracic region,
longitudinal bundles of fibres connect the tops of the spinous processes; they act against an augmentation of the thoracal kyphosis. Between thoracal kyphosis and lumbal lordosis there is no
exact course of the fibres of the interspinous ligts. ("thorakolumbaler "Ăbergangsbereich"). In the
lumbar spine the fibres of the interspinous ligts., being very strong, pass in a posterocranial
direction. They have the function of limitation the range of flexion ventrally and of limiting backwards - shifting of the cranial vertebra in dorsal-flexion.
In the lumbosacral segment additional fibres, arising from the top of the 5th lumbar spinous
process, pass in a posterocaudal direction and interlace with the thoracolumbar fascia , whose fibres
form â below the 4 th lumbarvertebra â ascissor - latticed structure. The supraspinous ligt. lies
superficially to the thoracolumbar fascia. Its fibres pass several spinous processes. I t ends caudally
at the 4th lumbar spinous process
Description of Drip-Line Nuclei within Relativistic Mean-Field Plus BCS Approach
Recently it has been demonstrated, considering Ni and Ca isotopes as
prototypes, that the relativistic mean-field plus BCS (RMF+BCS) approach
wherein the single particle continuum corresponding to the RMF is replaced by a
set of discrete positive energy states for the calculation of pairing energy
provides a good approximation to the full relativistic Hartree-Bogoliubov (RHB)
description of the ground state properties of the drip-line neutron rich
nuclei. The applicability of RMF+BCS is essentially due to the fact that the
main contribution to the pairing correlations is provided by the low-lying
resonant states. General validity of this approach is demonstrated by the
detailed calculations for the ground state properties of the chains of isotopes
of O, Ca, Ni, Zr, Sn and Pb nuclei. The TMA and NL-SH force parameter sets have
been used for the effective mean-field Lagrangian. Comprehensive results for
the two neutron separation energy, rms radii, single particle pairing gaps and
pairing energies etc. are presented. The Ca isotopes are found to exhibit
distinct features near the neutron drip line whereby it is found that further
addition of neutrons causes a rapid increase in the neutron rms radius with
almost no increase in the binding energy, indicating the occurrence of halos. A
comparison of these results with the available experimental data and with the
recent continuum relativistic Hartree-Bogoliubov (RCHB) calculations amply
demonstrates the validity and usefulness of this fast RMF+BCS approach.Comment: 59 pages, 40 figure
New effective interactions in RMF theory with non-linear terms and density-dependent meson-nucleon coupling
New parameter sets for the Lagrangian density in the relativistic mean field
(RMF) theory, PK1 with nonlinear sigma- and omega-meson self-coupling, PK1R
with nonlinear sigma-, omega- and rho-meson self-coupling and PKDD with the
density-dependent meson-nucleon coupling, are proposed. They are able to
provide an excellent description not only for the properties of nuclear matter
but also for the nuclei in and far from the valley of beta-stability. For the
first time in the parametrization of the RMF Lagrangian density, the
center-of-mass correction is treated by a microscopic way, which is essential
to unify the description of nuclei from light to heavy regions with one
effective interaction.Comment: 22 pages, 16 EPS figures, RevTeX
PREHISTORIC CREMATIONS FROM NOGALES, ARIZONA *
In October, 1969, the Highway Salvage Section of the Arizona State Museum conducted emergency salvage excavations in conjunction with the construction of the Tucson-Nogales Highway. Ten cremations were recovered from a backhoe trench which had been placed within the city limits of Nogales, Arizona. Analysis of the cremations indicated cultural contact between the Trincheras culture of Sonora, Mexico, and the Hohokam culture of the Santa Cruz River Valley in southern Arizona
Relativistic Hartree-Bogoliubov Approach for Nuclear Matter with Non-Linear Coupling Terms
We investigate the pairing property of nuclear matter with Relativistic
Hartree-Bogoliubov(RHB) approach. Recently, the RHB approach has been widely
applied to nuclear matter and finite nuclei. We have extended the RHB approach
to be able to include non-linear coupling terms of mesons. In this paper we
apply it to nuclear matter and observe the effect of non-linear terms on
pairing gaps.Comment: 13 pages, 5 figure
Effective hadron masses and couplings in nuclear matter and incompressibility
The role of effective hadron masses and effective couplings in nuclear matter
is studied using a generalized effective Lagrangian for sigma-omega model. A
simple relation among the effective masses, the effective couplings and the
incompressibility K is derived. Using the relation, it is found that the
effective repulsive and the effective attractive forces are almost canceled to
each other at the normal density. Inversely, if this cancellation is almost
complete, K should be 250-350MeV.Comment: 13 pages of text, 16 figure
Projection and ground state correlations made simple
We develop and test efficient approximations to estimate ground state
correlations associated with low- and zero-energy modes. The scheme is an
extension of the generator-coordinate-method (GCM) within Gaussian overlap
approximation (GOA). We show that GOA fails in non-Cartesian topologies and
present a topologically correct generalization of GOA (topGOA). An RPA-like
correction is derived as the small amplitude limit of topGOA, called topRPA.
Using exactly solvable models, the topGOA and topRPA schemes are compared with
conventional approaches (GCM-GOA, RPA, Lipkin-Nogami projection) for
rotational-vibrational motion and for particle number projection. The results
shows that the new schemes perform very well in all regimes of coupling.Comment: RevTex, 12 pages, 7 eps figure
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