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.

Observation of unconventional edge states in ‘photonic graphene’

Abstract: The propagation of light in photonic crystals with a honeycomb structure mirrors the behaviour of charges in graphene, therefore allowing for the investigation of electronic properties that cannot otherwise be accessed in graphene itself. This approach is now used to predict unexpected edge states that localize in the bearded edges of hexagonal lattices.

Managing the Crowd: Towards a Taxonomy of Crowdsourcing Processes

Abstract: Crowdsourcing is an umbrella term for a variety of approaches that tap into the potential of a large and open crowd of people. So far, there is no systematic understanding of the processes used to source and aggregate contributions from the crowd. In particular, crowdsourcing organizations striving to achieve a specific goal should be able to evaluate the mechanisms that impact these processes. Following a method of IS taxonomy development we propose a new taxonomic framework for crowdsourcing processes. In contrast to previous work, this classification scheme focuses exclusively on an organizational perspective and on the mechanisms available to these organizations. The resulting dimensions are preselection of contributors, accessibility of peer contributions, aggregation of contributions, and remuneration for contributions. By classifying the processes of 46 crowdsourcing examples, we identify 19 distinct process types. A subsequent cluster analysis shows general patterns among these types and indicates a link to certain applications of crowdsourcing.

Successful Aging and Its Discontents: A Systematic Review of the Social Gerontology Literature

Abstract: Purpose of the study The purpose of this study was to analyze the range of critiques of successful aging models and the suggestions for improvement as expressed in the social gerontology literature. Design and methods We conducted a systematic literature review using the following criteria: journal articles retrieved in the Abstracts in Social Gerontology, published 1987-2013, successful aging/ageing in the title or text (n = 453), a critique of successful aging models as a key component of the article. Sixty-seven articles met the criteria. Qualitative methods were used to identify key themes and inductively configure meanings across the range of critiques. Results The critiques and remedies fell into 4 categories. The Add and Stir group suggested a multidimensional expansion of successful aging criteria and offered an array of additions. The Missing Voices group advocated for adding older adults' subjective meanings of successful aging to established objective measures. The Hard Hitting Critiques group called for more just and inclusive frameworks that embrace diversity, avoid stigma and discrimination, and intervene at structural contexts of aging. The New Frames and Names group presented alternative ideal models often grounded in Eastern philosophies. Implications The vast array of criteria that gerontologists collectively offered to expand Rowe and Kahn's original successful model is symptomatic of the problem that a normative model is by definition exclusionary. Greater reflexivity about gerontology's use of "successful aging" and other normative models is needed.

Habitat-dependent song divergence in the little greenbul: an analysis of environmental selection pressures on acoustic signals

Abstract: Bird song is a sexual trait important in mate choice and known to be shaped by environmental selection. Here we investigate the ecological factors shaping song variation across a rainforest gradient in central Africa. We show that the little greenbul (Andropadus virens), previously shown to vary morphologically across the gradient in fitness-related characters, also varies with respect to song characteristics. Acoustic features, including minimum and maximum frequency, and delivery rate of song notes showed significant differences between habitats. In contrast, we found dialectal variation independent of habitat in population-typical songtype sequences. This pattern is consistent with ongoing gene flow across habitats and in line with the view that song variation in the order in which songtypes are produced is not dependent on habitat characteristics in the same way physical song characteristics are. Sound transmission characteristics of the two habitats did not vary significantly, but analyses of ambient noise spectra revealed dramatic and consistent habitat-dependent differences. Matching between low ambient noise levels for low frequencies in the rainforest and lower minimal frequencies in greenbul songs in this habitat suggests that part of the song divergence may be driven by habitat-dependent ambient noise patterns. These results suggest that habitat-dependent selection may act simultaneously on traits of ecological importance and those important in prezygotic isolation, leading to an association between morphological and acoustic divergence. Such an association may promote assortative mating and may be a mechanism driving reproductive divergence across ecological gradients.