Floristic and Biogeographical Trends in Seaweed Assemblages from a Subtropical Insular Island Complex in the Gulf of California

Floristic and biogeographical trends of the seaweed assemblages in subtidial rocky areas were evaluated at 10 sites around Espiritu Santo Island in the Gulf of California. Seasonal sampling in two consecutive years with intensive surveys in a 500-m2 area at each site was done. An intensive search was made of previous records from the literature. We found 85 species in the field with an additional 69 species from the literature, for a total 116 species. Species composition was significantly different between sides of the island in the first year, but very similar in the second. Species composition was not influenced by the presence of epiphytes. Phenologically, most species were ephemeral or annual with a low reproductive effort. Biogeographically, tropical elements dominated, but there was an important contribution from temperate species. Our results indicate that Espiritu Santo Island is a dynamic system that is strongly influenced by local oceanographic conditions

A critical appraisal of ATLAS9 and NextGen 5 model atmospheres

The fitting atmosphere parameters (Teff, g, and [Fe/H]) for over 300 stars in the Gunn & Striker and Jacoby et al. catalogs have been obtained relying on the Kurucz (1992) ATLAS9 and Hauschildt et al (1999) NextGen5 synthesis models. The output results are compared, and a critical appraisal of both theoretical codes is performed.Comment: 2 pages, 2 figures; proceedings of "New Quests in Stellar Astrophysics: The link between Stars and Cosmology", 26-30 March, 2001, Puerto Vallarta, Mexico, eds. M. Chavez, A. Bressan, A. Buzzoni & D. Mayya, to be published by the Kluwer Academic Publisher

A Grid of Synthetic Stellar UV Fluxes

We present preliminary results of a large project aimed at creating an extended theoretical and observational database of stellar spectra in the ultraviolet wavelength range. This library will consist of IUE spectra at low and high resolution, and a set of LTE and NLTE theoretical fluxes. A first grid of 50 model fluxes with solar metallicity, in the wavelength interval 1000 - 4400 AA, is reported here. Calculations are based on the Kurucz (1993) SYNTHE code. The models span effective temperatures between 10,000 K and 50,000 K, and a surface gravity in the range 2.5 <= log g <= 5.0 dex.Comment: 2 pages, 1 figure, To appear in proceedings, "New Quests in Stellar Astrophysics: The Link Between Stars and Cosmology ", March 26-30, 2001, Eds. M. Chavez, A. Bressan, A. Buzzoni & D. Mayy