Calcium Triplet Synthesis

We present theoretical equivalent widths for the sum of the two strongest lines of the Calcium Triplet, CaT index, in the near-IR, using evolutionary techniques and the most recent models and observational data for this feature in individual stars. We compute the CaT index for Single Stellar Populations (instantaneous burst, standard Salpeter-type IMF) at four metallicities, Z=0.004, 0.008, 0.02 (solar) and 0.05, and ranging in age from very young bursts of star formation (few Myr) to old stellar populations, up to 17 gyr, representative of globular clusters, elliptical galaxies and bulges of spirals. The interpretation of the observed equivalent widths of CaT in different stellar systems is discussed. Composite-population models are also computed as a tool to interpret the CaT detections in star-forming regions, in order to disantangle between the component due to Red Supergiants stars, RSG, and the underlying, older, population. CaT is found to be an excellent metallicity-indicator for populations older than 1 Gyr, practically independent of the age. We discuss its application to remove the age- metallicity degeneracy, characteristic of all studies of galaxy evolution based on the usual integrated indices (both broad band colors and narrow band indices). The application of the models computed here to the analysis of a sample of elliptical galaxies will be discussed in a forthcoming paper (Gorgas et al. 1998).Comment: 17 pages, 7 figures, to be published in A&

What is the impact of duplicate coverage on the demand for health care in Germany?

Duplicate coverage involves those individuals who hold public health insurance, and purchase additional private coverage. Using data from the German Institute for Economic Research, we try to investigate the impact of duplicate coverage on the demand for healthcare (measured in number of visits to doctors). Given the simultaneity of the choices to take out additional private health insurance coverage, we estimate a negative binomial model to measure this impact. We also estimate a a Full Information Maximun Loglikelihood (FIML), known as Endogenous Switching Poisson Count Model and we compare these results with the standard maximum log likelihood (ML) estimators of the negative binomial model. The Results show that, there is a positive difference on the level of health services demanded when there is a duplicate coverage. We found also that there is evidence to think that in Germany there is a feedback between duplicate coverage and the demand of health services.Health care services demand, health insurance