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.

Seed dispersal by Ceratogymna hornbills in the Dja Reserve, Cameroon

Abstract: Seed dispersal is a process critical to the maintenance of tropical forests, yet little is known about the interactions of most dispersers with their communities. In the Dja Reserve, Cameroon, seed dispersal by the hornbills Cerato- gymna atrata, C. cylindricus and C. fistulator (Aves: Bucerotidae) was evaluated with respect to the taxonomic breadth of plants dispersed, location of seed deposition and effects on seed germination. Collectively, the three hornbill species consumed fruits from 59 tree and liana species, and likely provided dispersal for 56 of them. Hornbill-dispersed tree species composed 22% of the known tree flora of the site. Hornbill visit lengths, visit frequencies, and seed passage times indicated that few seeds were deposited beneath parent trees; in five hornbill/tree species pairings studied, 69-100% of the seeds ingested were deposited away from the parent trees. Germination trials showed that hornbill gut passage is gentle on seeds. Of 24 tree species tested, 23 germinated after passage by hornbills; of 17 planted with con- trols taken directly from trees, only four species showed evidence of inhibition of germination rate, while seven experienced unchanged germination rates and six experienced enhanced germination rates. Results suggested that Ceratogymna horn- bills rank among the most important seed dispersers found in Afrotropical forests, and they deserve increased conservation attention. Ceratogymna hornbills are likely to become increasingly important in forest regeneration as populations of larger mammalian seed dispersers (such as forest elephants and primates) diminish.

Defect modes in one-dimensional photonic lattices.

Abstract: Linear defect modes in one-dimensional photonic lattices are studied theoretically. For negative (repulsive) defects, various localized defect modes are found. The strongest confinement of the defect modes appears when the lattice intensity at the defect site is nonzero rather than zero. When launched at small angles into such a defect site of the lattice, a Gaussian beam can be trapped and undergo snake oscillations under appropriate conditions.

Discrimination and the Political Economy of Environmental Inequality

Abstract: Over the last decade there has been a surge in academic and scientific inquiry into disparities in environmental hazards among diverse communities. Much of the evidence points to a general pattern of disproportionate exposures to toxics among communities of color and the poor, with racial differences often persisting across economic strata. Although results have implications for the politics of environmental decisionmaking, most of these analyses are limited to illustrating how inequities in exposures and health risks are spread across the landscape, while shedding little light on their origins or the reasons for their persistence. Previous attempts to theorize the causes of environmental inequality have focused on procedural justice in the regulatory arena, emphasizing civil rights jurisprudence and social theories on individual and institutional discrimination. Although these approaches offer insights into the epistemology of environmental inequality, they fail adequately to account for the political ec...

Dissipative hydrodynamics in superspace

Abstract: We construct a Schwinger-Keldysh effective field theory for relativistic hydrodynamics for charged matter in a thermal background using a superspace formalism. Superspace allows us to efficiently impose the symmetries of the problem and to obtain a simple expression for the effective action. We show that the theory we obtain is compatible with the Kubo-Martin-Schwinger condition, which in turn implies that Green’s functions obey the fluctuation-dissipation theorem. Our approach complements and extends existing formulations found in the literature.