San Francisco State University

About: San Francisco State University is a education organization based out in San Francisco, California, United States. It is known for research contribution in the topics: Population & Planet. The organization has 5669 authors who have published 11433 publications receiving 408075 citations. The organization is also known as: San Francisco State & San Francisco State Normal School.

Ecology and speciation

Abstract: Recent studies on diverse taxa suggest that natural selection caused by shifts in ecology or invasions of novel habitats plays an important role in adaptive divergence and speciation. Exciting new studies integrating approaches from both the field and the laboratory suggest that ecological shifts can result in extremely rapid rates of evolutionary divergence. Although experimental approaches that link rapid ecological divergence to reproductive isolation and speciation are in their infancy, recent research indicates those approaches that will be most useful.

A ~7.5 M⊕ Planet Orbiting the Nearby Star, GJ 876*

Abstract: High-precision, high-cadence radial velocity monitoring over the past 8 yr at the W. M. Keck Observatory reveals evidence for a third planet orbiting the nearby (4.69 pc) dM4 star GJ 876. The residuals of three-body Newtonian fits, which include GJ 876 and Jupiter-mass companions b and c, show significant power at a periodicity of 1.9379 days. Self-consistently fitting the radial velocity data with a model that includes an additional body with this period significantly improves the quality of the fit. These four-body (three-planet) Newtonian fits find that the minimum mass of companion "d" is m sin i = 5.89 ± 0.54 M⊕ and that its orbital period is 1.93776 (±7 × 10-5) days. Assuming coplanar orbits, an inclination of the GJ 876 planetary system to the plane of the sky of ~50° gives the best fit. This inclination yields a mass for companion d of m = 7.53 ± 0.70 M⊕, making it by far the lowest mass companion yet found around a main-sequence star other than our Sun. Precise photometric observations at Fairborn Observatory confirm low-level brightness variability in GJ 876 and provide the first explicit determination of the star's 96.7 day rotation period. Even higher precision short-term photometric measurements obtained at Las Campanas imply that planet d does not transit GJ 876.

Ethnic identity and the academic adjustment of adolescents from Mexican, Chinese, and European backgrounds.

Abstract: The association of adolescents' ethnic identification with their academic attitudes and achievement was examined among a sample of 589 ninth-grade students from Mexican, Chinese, and European backgrounds. Adolescents from all backgrounds chose a variety of ethnic labels to describe themselves, with those from Mexican, Chinese, and immigrant families incorporating more of their families' national origin and cultural background into their chosen ethnic labels. Nevertheless, the strength of adolescents' ethnic identification was more relevant to their academic adjustment than the specific labels that they chose, and it was most important for the extra motivation necessary for ethnic minority students to attain the same level of academic success as their European American peers.

Skin microbes on frogs prevent morbidity and mortality caused by a lethal skin fungus

Abstract: Emerging infectious diseases threaten human and wildlife populations. Altered ecological interactions between mutualistic microbes and hosts can result in disease, but an understanding of interactions between host, microbes and disease-causing organisms may lead to management strategies to affect disease outcomes. Many amphibian species in relatively pristine habitats are experiencing dramatic population declines and extinctions due to the skin disease chytridiomycosis, which is caused by the chytrid fungus Batrachochytrium dendrobatidis. Using a randomized, replicated experiment, we show that adding an antifungal bacterial species, Janthinobacterium lividum, found on several species of amphibians to the skins of the frog Rana muscosa prevented morbidity and mortality caused by the pathogen. The bacterial species produces the anti-chytrid metabolite violacein, which was found in much higher concentrations on frog skins in the treatments where J. lividum was added. Our results show that cutaneous microbes are a part of amphibians' innate immune system, the microbial community structure on frog skins is a determinant of disease outcome and altering microbial interactions on frog skins can prevent a lethal disease outcome. A bioaugmentation strategy may be an effective management tool to control chytridiomycosis in amphibian survival assurance colonies and in nature.

Residents’ Attitudes toward Existing and Future Tourism Development in Rural Communities

Abstract: Building on the model by Perdue, Long, and Allen, this study examined residents’ attitudes toward existing and future tourism development in several rural areas at different stages of tourism and economic development. Social exchange theory and destination life cycle model were used to examine the impacts of tourism development on residents’ attitudes when considered in conjunction with a community’s total economic activity. New social predictors and endogenous factors were tested in the model. Overall, residents of three distinct rural county-level areas were supportive of tourism development, and little evidence was found that suggests that attitudes toward tourism become negative with higher levels of tourism. After considering the level of tourism development in conjunction with the total economic activity, residents of the three county-level areas showed some signs of destination life cycle influencing their own relationship with tourism.