Once-ionized helium in superstrong magnetic fields

It is generally believed that magnetic fields of some neutron stars, the so-called magnetars, are enormously strong, up to 10^{14} - 10^{15} G. Recent investigations have shown that the atmospheres of magnetars are possibly composed of helium. We calculate the structure and bound-bound radiative transitions of the He^+ ion in superstrong fields, including the effects caused by the coupling of the ion's internal degrees of freedom to its center-of-mass motion. We show that He^+ in superstrong magnetic fields can produce spectral lines with energies of up to about 3 keV, and it may be responsible for absorption features detected recently in the soft X-ray spectra of several radio-quiet isolated neutron stars. Quantization of the ion's motion across a magnetic field results in a fine structure of spectral lines, with a typical spacing of tens electron-volts in magnetar-scale fields. It also gives rise to ion cyclotron transitions, whose energies and oscillator strengths depend on the state of the bound ion.Comment: 12 pages, including 3 figures. Submitted to ApJ Letters (revised version

DIVERSITY IN HUNTER-GATHERER LANDSCAPES IN THE NORTH AMERICAN MIDCONTINENT

The thesis examines changes in hunter-gatherer land-use along lower Cypress Creek, atributary of the Green River located in west-central Kentucky. Presented, are the results of the firstthree years of site survey and museum work conducted by the Cypress Creek Archaeological Project.Analysis of site location and hafted bifaces suggests that, throughout the Holocene, increasingemphasis was placed on certain locations and areas of the landscape. Comparison of the CypressCreek study area with other areas of Archaic research indicate that land-use was highly variable inboth space and time across the North American midcontinent

Thinking about Crime: Race and Lay Accounts of Lawbreaking Behavior

Lay or commonsense accounts of the origins of criminal behavior may play a key role in sustaining a strong public appetite for harsh criminal justice policies and undergird large black-white differences in opinion in this domain. Using data from the nationally representative Race, Crime, and Public Opinion project’s 2001 survey, the authors develop an explanatory mode typology for accounts of involvement in criminal behavior. These include both individualistic and structural accounts of behavior in addition to a mixed-mode category. The authors identify key differences in the demographic and sociopolitical bases of the attributional types and find significant race differences in these attributional types. Attributions strongly affect how individuals wish to see public policy respond to the problem of crime and explain a small but significant fraction of the black-white difference in crime policy views.African and African American StudiesSociolog

Role of metal-dependent regulation of ESX-3 secretion in intracellular survival of Mycobacterium tuberculosis

More people die every year from Mycobacterium tuberculosis infection than from infection by any other bacterial pathogen. Type VII secretion systems (T7SS) are used by both environmental and pathogenic mycobacteria to secrete proteins across their complex cell envelope. In the nonpathogen Mycobacterium smegmatis, the ESX-1 T7SS plays a role in conjugation, and the ESX-3 T7SS is involved in metal homeostasis. In M. tuberculosis, these secretion systems have taken on roles in virulence, and they also are targets of the host immune response. ESX-3 secretes a heterodimer composed of EsxG (TB9.8) and EsxH (TB10.4), which impairs phagosome maturation in macrophages and is essential for virulence in mice. Given the importance of EsxG and EsxH during infection, we examined their regulation. With M. tuberculosis, the secretion of EsxG and EsxH was regulated in response to iron and zinc, in accordance with the previously described transcriptional response of the esx-3 locus to these metals. While iron regulated the esx-3 expression in both M. tuberculosis and M. smegmatis, there is a significant difference in the dynamics of this regulation. In M. smegmatis, the esx-3 locus behaved like other iron-regulated genes such as mbtB. In M. tuberculosis, both iron and zinc modestly repressed esx-3 expression. Diminished secretion of EsxG and EsxH in response to these metals altered the interaction of M. tuberculosis with macrophages, leading to impaired intracellular M. tuberculosis survival. Our findings detail the regulatory differences of esx-3 in M. tuberculosis and M. smegmatis and demonstrate the importance of metal-dependent regulation of ESX-3 for virulence in M. tuberculosis

Contemplating the history and future of radiocarbon dating in the American Southeast

We consider the history, present, and future of radiocarbon dating in the American Southeast. We point out some of the past and present flaws related to archaeological research and dating. Our approach to this review is rooted in the perspective that each radiocarbon date collectively adds to our knowledge of the region and not just a particular site. Based on our observations, we suggest some “good” practices with respect to certain aspects of radiocarbon dating. Our concluding discussion considers Bayesian chronological analysis and the growing contribution of chronological modeling to the Southeast

Recent Legal Literature

Dallas: Analytical Tables of the Law of Evidence, for use with Stephen\u27s Digest of the Law of Evidence; Taylor: The American Law of Landlord and Tenan

LAURA Users Manual: 5.6

This users manual provides in-depth information concerning installation and execution of Laura, version 5. Laura is a structured, multiblock, computational aerothermodynamic simulation code. Version 5 represents a major refactoring of the original Fortran 77 Laura code toward a modular structure afforded by Fortran 95. The refactoring improved usability and maintainability by eliminating the requirement for problem-dependent recompilations, providing more intuitive distribution of functionality, and simplifying inter- faces required for multi-physics coupling. As a result, Laura now shares gas-physics modules, MPI modules, and other low-level modules with the Fun3D unstructured-grid code. In addition to internal refactoring, several new features and capabilities have been added, e.g., a GNU-standard installation process, parallel load balancing, automatic trajectory point sequencing, free-energy minimization, and coupled ablation and flow field radiation