7,176 research outputs found
Nuclear Superconductivity in Compact Stars: BCS Theory and Beyond
This chapter provides a review of microscopic theories of pairing in nuclear
systems and neutron stars. Special attention is given to the mean-field BCS
theory and its extensions to include effects of polarization of the medium and
retardation of the interactions. Superfluidity in nuclear systems that exhibit
isospin asymmetry is studied. We further address the crossover from the
weak-coupling BCS description to the strong-coupling BEC limit in dilute
nuclear systems. Finally, within the observational context of rotational
anomalies of pulsars, we discuss models of the vortex state in superfluid
neutron stars and of the mutual friction between superfluid and normal
components, along with the possibility of type-I superconductivity of the
proton subsystem.Comment: 41 pages, 16 figures. Chapter contributed to "Pairing in Fermionic
Systems: Basic Concepts and Modern Applications", World Scientifi
Many-body methods for nuclear systems at subnuclear densities
This article provides a concise review of selected topics in the many-body
physics of low density nuclear systems. The discussion includes the
condensation of alpha particles in supernova envelopes, formation of three-body
bound states and the BEC-BCS crossover in dilute nuclear matter, and neutrino
production in -wave paired superfluid neutron matter.Comment: 10 pages, 3 figures. Talk given by AS at "Recent Progress in
Many-Body Theories 14", Barcelona, 2007. To be published by World Sci., eds.
G.E. Astrakharchik, J. Boronat, and F. Mazzant
The subnuclear localization of tRNA ligase in yeast
Yeast tRNA ligase is an enzyme required for tRNA splicing. A study by indirect immune fluorescence shows that this enzyme is localized in the cell nucleus. At higher resolution, studies using indirect immune electron microscopy show this nuclear location to be primarily at the inner membrane of the nuclear envelope, most likely at the nuclear pore. There is a more diffuse, secondary location of ligase in a region of the nucleoplasm within 300 nm of the nuclear envelope. When the amount of ligase in the cell is increased, nuclear staining increases but staining of the nuclear envelope remains constant. This experiment indicates that there are a limited number of ligase sites at the nuclear envelope. Since the other tRNA splicing component, the endonuclease, has the characteristics of an integral membrane protein, we hypothesize that it constitutes the site for the interaction of ligase with the nuclear envelope
Results Of Metal Detector Survey, Testing Operations, And Archival Studies The Wooten-Seale Plantation, Site 41RT362 Robertson County, Texas
Preliminary historical and archaeological investigation of the Robert Henry Seale farm residences (41RT362) utilizin g a metal detector and limited shovel testing indicate that a recent owner of the property removed both residential structures, destroying the site and extensively damaging any buried deposits. It is the estimation of the cultural resources staff of the State Department of Highways and Public Transportation that the physical remains of the occupation of the property have been disrupted to such an extent that they now have no value in answering cultural- historical questions
Archaeological Test Excavations at 41KF118 Kaufman County, Texas
Site 41KF118 was discovered during construction of improvements to SH 34 in Kaufman County and was tested in April 1990, to determine its eligibility for inclusion in the National Register of Historic Places. Materials recovered as a result of test excavations suggest a Late Archaic occupation for that portion of the site within the right-of-way. Most of the site lies southeast of the highway right-of-way. Tests also showed the cultural deposits to be sparse and badly disturbed by previous land clearing operations and cultivation. No additional work is recommended at this site
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