Experimental Consequences of Time Variations of the Fundamental Constants

We discuss the experimental consequences of hypothetical time variations of the fundamental constants. We emphasize that from a purely phenomenological point of view, only dimensionless fundamental constants have significance. Two classes of experiments are identified that give results that are essentially independent of the values of all constants. Finally, we show that experiments that are generally interpreted in terms of time variations of the dimensioned gravitional constant $G$ are better interpreted as giving limits on the variation of the dimensionless constant $\alpha_G=Gm_p^2/\hbar c$.Comment: 9 pages, 1 figur

A process yields large quantities of pure ribosome subunits

Development of process for in-vitro protein synthesis from living cells followed by dissociation of ribosomes into subunits is discussed. Process depends on dialysis or use of chelating agents. Operation of process and advantages over previous methods are outlined

K Giants in Baade's Window. II. The Abundance Distribution

This is the second in a series of papers in which we analyze spectra of over 400 K and M giants in Baade's Window, including most of the stars with proper motions measured by Spaenhauer et al. [AJ, 103, 297 (1992)]. In our first paper, we measured line--strength indices of Fe, Mg, CN and H$\beta$ and calibrated them on the system of Faber et al. [ApJS, 57, 711 (1985)]. Here, we use the $\langle{\rm Fe}\rangle$ index to derive an abundance distribution in [Fe/H] for 322 stars with effective temperatures between 3900 K and 5160 K. Our derived values of [Fe/H] agree well with those measured from high--resolution echelle spectra (e.g., McWilliam \& Rich [ApJS, 91, 749 (1994)]) for the small number of stars in common. We find a mean abundance $\langle{\rm [Fe/H]}\rangle = -0.11 \pm 0.04$ for our sample of Baade's Window K giants. More than half the sample lie in the range $-0.4 <$ \feh\ $<+0.3$. We estimate line--of--sight distances for individual stars in our sample and confirm that, in Baade's Window, most K giants with $V < 15.5$ are foreground disk stars, but the great majority (more than 80\%) with $V > 16$ belong to the bulge. We also compare the metallicities derived from the CN and Mg$_2$ indices to those from iron. Most of the metal--rich stars in our sample appear to be CN--weak, in contrast to the situation in metal--rich globular clusters and elliptical galaxies. The metal--poor half of our sample ([Fe/H] $< 0$) shows evidence for a mild Mg overenhancement ([Mg/Fe] $\sim +0.2$); but this is not seen in the more metal--rich stars ([Fe/H] $\geq$ 0). The K giants in Baade's Window therefore share some, but not all, of the characteristics of stars in elliptical galaxies as inferred from their integrated light.Comment: Accepted for publication in the Astronomical Journal, tentatively scheduled for July, 1996. LaTex source which generates 40 pages of text (no figures or tables). Complete (text + 15 figs + 5 tables) preprint in gzip/tar format is also available at ftp://bessel.mps.ohio-state.edu/pub/terndrup/kg2.tar.gz (227 kbyte

Flight service evaluation of composite helicopter components

An assessment of composite helicopter structures, exposed to environmental effects, after four years of commercial service is presented. This assessment is supported by test results of helicopter components and test panels which have been exposed to environmental effects since late 1979. Full scale static and fatigue tests are being conducted on composite components obtained from S-76 helicopters in commercial operations in the Gulf Coast region of Louisiana. Small scale tests are being conducted on coupons obtained from panels being exposed to outdoor conditions in Stratford, Connecticut and West Palm Beach, Florida. The panel layups represent S-76 components. Moisture evaluations and strength tests are being conducted, on the S-76 components and panels, over a period of eight years. Results are discussed for components and panels with up to four years of exposure

Taxes and Unmarried Fathers’ Participation in the Underground Economy

In this paper we employ data from the Fragile Families and Child Well-Being Study in order to estimate a model of underground labor supply developed by Lemieux et al. (1994). We focus specifically on the underground labor supply of unmarried fathers, a group that is likely to have significant involvement in the underground economy. We also extend the empirical analysis of Lemieux et al. by taking into account exogenous state and local variation in marginal tax rates, as well as sociodemographic variables related to the likelihood of participation in the underground. In accordance with expectations, we find that a significant proportion of unmarried fathers report participation in the underground. However, although the theoretical model predicts a positive relationship between the tax rate and underground hours of work (under certain conditions), we find that the effect of the tax rate on hours is statistically indistinguishable from zero, even after including exogenous variation in tax rates. We also fail to find a positive and statistically significant effect of the tax rate on participation in the underground. Within the context of the model, these results have specific implications for the magnitudes of the probability of detection and the penalty on evaded tax. Therefore, we conclude that additional empirical information is needed regarding these parameters. Future research might also employ other datasets in the estimation of the theoretical model outlined by Lemieux et al., as well as investigate the applicability of other models of underground labor supply.

New Methods for Integrated Models of Animal Disease Control

Accurate assessments of the epidemiological and economic impacts of an animal disease require the incorporation of feedbacks between disease spread and production incentives. This paper motivates a new modeling framework that is sensitive to the dynamics of disease, production decisions and incentives, different livestock production systems, and their interaction through the use of an integrated system dynamics framework. Preliminary simulation results are provided to demonstrate proof-of-concept of such an approach, with additional discussion given on extensions and implications of integrated methods.Animal disease control, simulation modeling, system dynamics, Livestock Production/Industries,

Finite element analysis of helicopter structures

Application of the finite element analysis is now being expanded to three dimensional analysis of mechanical components. Examples are presented for airframe, mechanical components, and composite structure calculations. Data are detailed on the increase of model size, computer usage, and the effect on reducing stress analysis costs. Future applications for use of finite element analysis for helicopter structures are projected