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.

A mechanistic model for river incision into bedrock by saltating bed load

Abstract: [1] Abrasion by bed load is a ubiquitous and sometimes dominant erosional mechanism for fluvial incision into bedrock. Here we develop a model for bedrock abrasion by saltating bed load wherein the wear rate depends linearly on the flux of impact kinetic energy normal to the bed and on the fraction of the bed that is not armored by transient deposits of alluvium. We assume that the extent of alluvial bed cover depends on the ratio of coarse sediment supply to bed load transport capacity. Particle impact velocity and impact frequency depend on saltation trajectories, which can be predicted using empirical functions of excess shear stress. The model predicts a nonlinear dependence of bedrock abrasion rate on both sediment supply and transport capacity. Maximum wear rates occur at moderate relative supply rates due to the tradeoff between the availability of abrasive tools and the partial alluviation of the bedrock bed. Maximum wear rates also occur at intermediate levels of excess shear stress due to the reduction in impact frequency as grain motion approaches the threshold of suspension. Measurements of bedrock wear in a laboratory abrasion mill agree well with model predictions and allow calibration of the one free model parameter, which relates rock strength to rock resistance to abrasive wear. The model results suggest that grain size and sediment supply are fundamental controls on bedrock incision rates, not only by bed load abrasion but also by all other mechanisms that require bedrock to be exposed in the channel bed.

Immigration as a social determinant of health

Abstract: Although immigration and immigrant populations have become increasingly important foci in public health research and practice, a social determinants of health approach has seldom been applied in this area. Global patterns of morbidity and mortality follow inequities rooted in societal, political, and economic conditions produced and reproduced by social structures, policies, and institutions. The lack of dialogue between these two profoundly related phenomena-social determinants of health and immigration-has resulted in missed opportunities for public health research, practice, and policy work. In this article, we discuss primary frameworks used in recent public health literature on the health of immigrant populations, note gaps in this literature, and argue for a broader examination of immigration as both socially determined and a social determinant of health. We discuss priorities for future research and policy to understand more fully and respond appropriately to the health of the populations affected by this global phenomenon.

An Empirical Study of Innate Consumer Innovativeness, Personal Characteristics, and New-Product Adoption Behavior

Abstract: This article explores the relationships between innate consumer innovativeness, personal characteristics, and new-product adoption behavior. To do this, the authors analyze cross-sectional data from a household panel using a structural equation modeling approach. They also test for potential moderating effects using a two-stage least square estimation procedure. They find that the personal characteristics of age and income are stronger predictors of new-product ownership in the consumer electronics category than innate consumer innovativeness as a generalized personality trait. The authors also find that personal characteristics neither influence innate consumer innovativeness nor moderate the relationship between innate consumer innovativeness and new-product adoption behavior.

Effect sizes for research: A broad practical approach.

Abstract: Preface. Introduction. Confidence Intervals for Comparing the Averages of Two Groups. The Standardized Difference Between Means. Correlational Effect Sizes for Comparing Two Groups. Effect Size Measures That Go Beyond Comparing Two Centers. Effect Sizes for One-Way Anova Designs. Effect Sizes for Factorial Designs. Effect Sizes for Categorical Variables. Effect Sizes for Ordinal Categorical Variables.

Elephant shark genome provides unique insights into gnathostome evolution

Abstract: The emergence of jawed vertebrates (gnathostomes) from jawless vertebrates was accompanied by major morphological and physiological innovations, such as hinged jaws, paired fins and immunoglobulin-based adaptive immunity. Gnathostomes subsequently diverged into two groups, the cartilaginous fishes and the bony vertebrates. Here we report the whole-genome analysis of a cartilaginous fish, the elephant shark (Callorhinchus milii). We find that the C. milii genome is the slowest evolving of all known vertebrates, including the ‘living fossil’ coelacanth, and features extensive synteny conservation with tetrapod genomes, making it a good model for comparative analyses of gnathostome genomes. Our functional studies suggest that the lack of genes encoding secreted calcium-binding phosphoproteins in cartilaginous fishes explains the absence of bone in their endoskeleton. Furthermore, the adaptive immune system of cartilaginous fishes is unusual: it lacks the canonical CD4 co-receptor and most transcription factors, cytokines and cytokine receptors related to the CD4 lineage, despite the presence of polymorphic major histocompatibility complex class II molecules. It thus presents a new model for understanding the origin of adaptive immunity. Whole-genome analysis of the elephant shark, a cartilaginous fish, shows that it is the slowest evolving of all known vertebrates, lacks critical bone formation genes and has an unusual adaptive immune system. The elephant shark (Callorhinchus milii) is a cartilaginous fish native to the temperate waters off southern Australia and New Zealand, living at depths of 200 to 500 metres and migrating into shallow waters during spring for breeding. The genome sequence is published in this issue of Nature. Comparison with other vertebrate genomes shows that it is the slowest evolving genome of all known vertebrates — coelacanth included. Genome analysis points to an unusual adaptive immune system lacking the CD4 receptor and some associated cytokines, indicating that cartilaginous fishes possess a primordial gnathostome adaptive immune system. Also absent are genes encoding secreted calcium-binding phosphoproteins, in line with the absence of bone in cartilaginous fish.