4,367 research outputs found

    Bandverbindungen der DornfortsÀtze der WirbelsÀule

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    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 "Übergangsbereich"). 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 — below the 4 th lumbarvertebra — 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

    The Cotton-Square Borer.

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    36 p

    Description of Drip-Line Nuclei within Relativistic Mean-Field Plus BCS Approach

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    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

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    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 *

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    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

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    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

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    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

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    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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