Effects of liquid and vapor cesium on structural materials

Literature survey on corrosive effects of liquid and vapor cesium on structural materials, and compatibility of cesium as working fluid for Rankine cycle space power plan

Topological structure of the SU(3) vacuum and exceptional eigenmodes of the improved Wilson-Dirac operator

We present a study of the instanton size and spatial distributions in pure SU(3) gauge theory using under-relaxed cooling. We also investigate the low-lying eigenmodes of the (improved) Wilson-Dirac operator, in particular, the appearance of zero-modes and their space-time localisation with respect to instantons in the underlying gauge field.Comment: Contribution to Lattice97 proceedings: 3 pages, LaTeX2e, 4 postscript figures, uses espcrc2.st

Low-Lying Eigenvalues of the Wilson-Dirac Operator

An exploratory study of the low-lying eigenvalues of the Wilson-Dirac operator and their corresonding eigenvectors is presented. Results for the eigenvalues from quenched and unquenched simulations are discussed. The eigenvectors are studied with respect to their localization properties in the quenched approximation for the cases of SU(2) and SU(3).Comment: Poster presented at LATTICE96(poster). 4 pages, LaTeX, fully coloured versions of Figs. 4 and 5 are included as separate gzipped PostScript files or can be obtained from http://www.desy.de/library/cgi-bin/showprep.pl?desy-rep%2F199615

Progressive managerial bonuses in a spatial Bertrand duopoly

The relationship of managerial bonuses and profit maximization is interesting both from an economic and a managerial viewpoint. Our contribution to this literature is showing that progressive managerial bonuses can increase profits in a spatial Bertrand competition, and furthermore they can help collusion

H_2 Absorption and Fluorescence for Gamma Ray Bursts in Molecular Clouds

If a gamma ray burst with strong UV emission occurs in a molecular cloud, there will be observable consequences resulting from excitation of the surrounding H2. The UV pulse from the GRB will pump H2 into vibrationally-excited levels which produce strong absorption at wavelengths < 1650 A. As a result, both the prompt flash and later afterglow will exhibit strong absorption shortward of 1650 A, with specific spectroscopic features. Such a cutoff in the emission from GRB 980329 may already have been observed by Fruchter et al.; if so, GRB 980329 was at redshift 3.0 < z < 4.4 . BVRI photometry of GRB 990510 could also be explained by H2 absorption if GRB 990510 is at redshift 1.6 < z < 2.3. The fluorescence accompanying the UV pumping of the H2 will result in UV emission from the GRB which can extend over days or months, depending on parameters of the ambient medium and beaming of the GRB flash. The 7.5-13.6 eV fluorescent luminosity is \sim 10^{41.7} erg/s for standard estimates of the parameters of the GRB and the ambient medium. Spectroscopy can distinguish this fluorescent emission from other possible sources of transient optical emission, such as a supernova.Comment: 13 pages, including 4 figures. submitted to Ap.J.(Letters

Structural and Magnetic Properties of Trigonal Iron

First principles calculations of the electronic structure of trigonal iron were performed using density function theory. The results are used to predict lattice spacings, magnetic moments and elastic properties; these are in good agreement with experiment for both the bcc and fcc structures. We find however, that in extracting these quantities great care must be taken in interpreting numerical fits to the calculated total energies. In addition, the results for bulk iron give insight into the properties of thin iron films. Thin films grown on substrates with mismatched lattice constants often have non-cubic symmetry. If they are thicker than a few monolayers their electronic structure is similar to a bulk material with an appropriately distorted geometry, as in our trigonal calculations. We recast our bulk results in terms of an iron film grown on the (111) surface of an fcc substrate, and find the predicted strain energies and moments accurately reflect the trends for iron growth on a variety of substrates.Comment: 11 pages, RevTeX,4 tar'd,compressed, uuencoded Postscript figure

Individual and contextual determinants of children's and adolescents’ mental health care use:A systematic review

To improve the access to children's mental health care, knowledge on the determinants of care use is important. Where previous systematic reviews mainly focus on parent-related factors, we are the first to systematically review individual and contextual determinants of mental health care use in children under the age of 18 years old. Five electronic databases were searched for studies on determinants of children's and adolescents’ mental health care use. Twenty-two longitudinal, population-based, quantitative studies were included based on eight inclusion criteria. The Behavioural Model of Health Service Use by Andersen was used for data synthesis. The quality of all studies was rated as high. Seven determinants were labelled with ‘good evidence’ of an association in this systematic review, namely screening programs for mental health problems, family composition, previous mental health care use, overall problem level, externalising behaviour, delinquent behaviour and impact/impairment. No association was found with age, urbanisation, and somatic complaints. Evidence was inconsistent for gender, socioeconomic position, ethnic background, internalising behaviour, aggressive behaviour and depression/anxiety. Little evidence was found for 27 determinants. This systematic review found ‘good evidence’ for seven determinants of children's mental health care use which could be used to improve the access to care. Quality of studies, direction for future research and implications for policy and practice are discussed. More insight is needed in contextual factors and factors for which limited or inconsistent evidence was found. These insights will contribute to decreasing the discrepancies in mental health care use and facilitating earlier intervention