Comment on Vacuum Stability and Electroweak Baryogenesis in the MSSM with Light Stops

We show that, for all values of $Tan \beta$ and the light right-handed stop mass for which the electroweak phase transition is strong enough to avoid washout following electroweak baryogenesis, the electroweak vacuum is stable over the lifetime of the observed Universe. Cosmological stability of the electroweak vacuum is violated only if the light right-handed stop is lighter than 100-115GeV.Comment: LaTex, 11 pages, no figures. Additions to text and reference

Anthropically Selected Baryon Number and Isocurvature Constraints

The similarity of the observed baryon and dark matter densities suggests that they are physically related, either via a particle physics mechanism or anthropic selection. A pre-requisite for anthropic selection is the generation of superhorizon-sized domains of different Omega_{B}/Omega_{DM}. Here we consider generation of domains of different baryon density via random variations of the phase or magnitude of a complex field Phi during inflation. Baryon isocurvature perturbations are a natural consequence of any such mechanism. We derive baryon isocurvature bounds on the expansion rate during inflation H_{I} and on the mass parameter mu which breaks the global U(1) symmetry of the Phi potential. We show that when mu < H_{I} (as expected in SUSY models) the baryon isocurvature constraints can be satisfied only if H_{I} is unusually small, H_{I} < 10^{7} GeV, or if non-renormalizable Planck-suppressed corrections to the Phi potential are excluded to a high order. Alternatively, an unsuppressed Phi potential is possible if mu is sufficiently large, mu > 10^{16} GeV. We show that the baryon isocurvature constraints can be naturally satisfied in Affleck-Dine baryogenesis, as a result of the high-order suppression of non-renormalizable terms along MSSM flat directions.Comment: 8 pages, 1 eps figure, LaTeX. Minor typo correcte

Aids and Economic Growth: A Human Capital Approach

It is estimated that by 2001 20 million people had died from AIDS, which is now the world´s fourth biggest cause of death. While the highest prevalence and death rates and number of infected persons are reported for sub-Saharan Africa, where life expectancies at birth are declining rapidly and infant mortality rates are increasing, there is evidence that the epidemic is accelerating in Asia and Eastern Europe. While the human and social costs of the HIV/AIDS epidemic are the major causes for concern, the econometric results reported in this paper indicate that the macroeconomic affects of the HIV/AIDS epidemic have been substantial; especially in Africa where the average marginal negative impact on income per capita of a one percent increase in HIV prevalence rate is 0.59 percent. Even in countries where the HIV prevalence rates are lower the marginal impacts are non trivial

Optical surface damage from reentrant gases on STS

The effect of an ammonia environment on the spectral reflectance of certain optical surfaces in the vacuum ultraviolet region was studied. In particular, the optical surfaces in the space shuttle were considered. Scans made of sample beams showed no change in the relative intensities before or after exposure to ammonia. Ammonia showed no effect on the Al/MgF2 mirror reflectance in the vacuum ultraviolet

Optical grating analyzer studies

A spectrometer was specifically designed and developed to observe grating spectra over a range of incidence angles from normal to almost grazing incidence. A unique scanning and focusing mechanism is utilized to keep the exit slit on the Rowland circle. Polarization effects in the vacuum were investigated, and efficiency measurements and spectral scans were made simultaneously with the spectrometer. Results of measurements are given. Applications of the spectrometer to the space program and to the study of contamination on optical surfaces are indicated