Directory of aerospace safety specialized information sources

Directory aids safety specialists in locating information sources and individual experts in engineering-related fields. Lists 170 organizations and approximately 300 individuals who can provide safety-related technical information in form of documentation, data, and consulting expertise. Information on hazard and failure cause identification, accident analysis, and materials characteristics are covered

Chuar, Hegel and Spencer

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Cepheid Masses: FUSE Observations of S Mus

S Mus is the Cepheid with the hottest known companion. The large ultraviolet flux means that it is the only Cepheid companion for which the velocity amplitude could be measured with the echelle mode of the HST GHRS. Unfortunately, the high temperature is difficult to constrain at wavelengths longer than 1200 \AA because of the degeneracy between temperature and reddening. We have obtained a FUSE spectrum in order to improve the determination of the temperature of the companion. Two regions which are temperature sensitive near 16,000 K but relatively unaffected by H$_2$ absorption (940 \AA, and the Ly $\beta$ wings) have been identified. By comparing FUSE spectra of S Mus B with spectra of standard stars, we have determined a temperature of 17,000 $\pm$ 500 K. The resultant Cepheid mass is 6.0 $\pm$ 0.4 M$_\odot$. This mass is consistent with main sequence evolutionary tracks with a moderate amount of convective overshoot.Comment: accepted to Ap

Border Zone Mass Transit Demad in Brownsville and Laredo

This study examines whether economic conditions in Mexico influence public transportation ridership levels in the border cities of Brownsville and Laredo, Texas. Besides the standard variables generally utilized to model bus ridership, additional indicators included in the empirical analysis are northbound pedestrian traffic and the real exchange rate index. Seemingly unrelated regression parameter estimates suggest that the volume of pedestrian border crossings in both cities is positively related to changes in ridership. The real exchange rate index in Laredo is negatively related to fluctuations in ridership, implying that peso appreciation increases transit utilization in this border city

Temperature dependence of the switching field distributions in all-perpendicular spin-valve nanopillars

We present temperature dependent switching measurements of the Co/Ni multilayered free element of 75 nm diameter spin-valve nanopillars. Angular dependent hysteresis measurements as well as switching field measurements taken at low temperature are in agreement with a model of thermal activation over a perpendicular anisotropy barrier. However, the statistics of switching (mean switching field and switching variance) from 20 K up to 400 K are in disagreement with a N\'{e}el-Brown model that assumes a temperature independent barrier height and anisotropy field. We introduce a modified N\'{e}el-Brown model thats fit the experimental data in which we take a $T^{3/2}$ dependence to the barrier height and the anisotropy field due to the temperature dependent magnetization and anisotropy energy.Comment: 5 pages, 4 figure

Mexico Evidence on the Regional Retail Impacts of Violent Crime

Prior research reports mixed results regarding the economic impacts of crime. This study employs data from all regions of Mexico, including border regions in both the north and the south, to examine the effects of homicides on retail activity across Mexico during a period of escalating violence. The results indicate that one additional homicide within a municipality eliminates one retail establishment and one paid job in the retail sector. Furthermore, the negative consequences of violent crime for retailers are augmented by proximity to an international border. This is consistent with previous research findings that cross-border shopping is a key feature of commerce along the international boundaries of Mexico. It suggests that crime waves may disproportionately impact border city retail activity by partially diverting customer traffic to stores located in neighboring countries. This result is also consistent with the finding of recent research that violent conflict in northern Mexico resulted in increased retail activity in some United States border cities