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.

Optical spatial solitons: historical overview and recent advances

Abstract: Solitons, nonlinear self-trapped wavepackets, have been extensively studied in many and diverse branches of physics such as optics, plasmas, condensed matter physics, fluid mechanics, particle physics and even astrophysics. Interestingly, over the past two decades, the field of solitons and related nonlinear phenomena has been substantially advanced and enriched by research and discoveries in nonlinear optics. While optical solitons have been vigorously investigated in both spatial and temporal domains, it is now fair to say that much soliton research has been mainly driven by the work on optical spatial solitons. This is partly due to the fact that although temporal solitons as realized in fiber optic systems are fundamentally one-dimensional entities, the high dimensionality associated with their spatial counterparts has opened up altogether new scientific possibilities in soliton research. Another reason is related to the response time of the nonlinearity. Unlike temporal optical solitons, spatial solitons have been realized by employing a variety of noninstantaneous nonlinearities, ranging from the nonlinearities in photorefractive materials and liquid crystals to the nonlinearities mediated by the thermal effect, thermophoresis and the gradient force in colloidal suspensions. Such a diversity of nonlinear effects has given rise to numerous soliton phenomena that could otherwise not be envisioned, because for decades scientists were of the mindset that solitons must strictly be the exact solutions of the cubic nonlinear Schrodinger equation as established for ideal Kerr nonlinear media. As such, the discoveries of optical spatial solitons in different systems and associated new phenomena have stimulated broad interest in soliton research. In particular, the study of incoherent solitons and discrete spatial solitons in optical periodic media not only led to advances in our understanding of fundamental processes in nonlinear optics and photonics, but also had a very important impact on a variety of other disciplines in nonlinear science. In this paper, we provide a brief overview of optical spatial solitons. This review will cover a variety of issues pertaining to self-trapped waves supported by different types of nonlinearities, as well as various families of spatial solitons such as optical lattice solitons and surface solitons. Recent developments in the area of optical spatial solitons, such as 3D light bullets, subwavelength solitons, self-trapping in soft condensed matter and spatial solitons in systems with parity-time symmetry will also be discussed briefly.

When Is a New Thing a Good Thing? Technological Change, Product Form Design, and Perceptions of Value for Product Innovations

Abstract: Innovation researchers recognize that the uncertainty with regard to the value-creating potential of product innovations increases with their technological novelty, and have argued that the usefulness and value of novel products are socially constructed. Despite this recognition, researchers have not explored how the outer form in which a technological innovation is embodied influences the processes through which the innovation's value is constructed and perceived. In this paper we argue that by embodying novel technologies in objects with specific functional, symbolic, and aesthetic properties, innovating firms also endow their products with cues that trigger a variety of cognitive and emotional responses. Drawing on psychological research we articulate how such cognitive and emotional responses underlie initial perceptions of value and theorize how innovating firms can influence them through product form design. Our framework explains how product form contributes to perceptions of value by modulating the actual technological novelty of a product innovation and facilitating how customers cope with it. Our theoretical framework makes an important contribution to innovation research and practice because it articulates how product form can be used strategically to achieve specific cognitive and emotional effects and enhance the initial customer perceptions of the value of an innovation.

Cosmic Star Formation History and Its Dependence on Galaxy Stellar Mass

Abstract: We examine the cosmic star formation rate (SFR) and its dependence on galaxy stellar mass over the redshift range 0.8 1010.8 M☉) was 6 times higher at z = 2 than it is today. It drops steeply from z = 2, reaching the present-day value at z ~ 1. In contrast, the SFR density of intermediate-mass galaxies (1010.2 M☉ ≤ M* < 1010.8 M☉) declines more slowly and may peak or plateau at z ~ 1.5. We use the characteristic growth time tSFR ≡ ρ/ρSFR to provide evidence of an associated transition in massive galaxies from a burst to a quiescent star formation mode at z ~ 2. Intermediate-mass systems transit from burst to quiescent mode at z ~ 1, while the lowest mass objects undergo bursts throughout our redshift range. Our results show unambiguously that the formation era for galaxies was extended and proceeded from high- to low-mass systems. The most massive galaxies formed most of their stars in the first ~3 Gyr of cosmic history. Intermediate-mass objects continued to form their dominant stellar mass for an additional ~2 Gyr, while the lowest mass systems have been forming over the whole cosmic epoch spanned by the GDDS. This view of galaxy formation clearly supports "downsizing" in the SFR where the most massive galaxies form first and galaxy formation proceeds from larger to smaller mass scales.

To Extend or Not to Extend: Success Determinants of Line Extensions:

Abstract: The authors study the determinants of line extension success using data on 75 line extensions of 34 cigarette brands over a 20-year period to investigate the relative effects of brand, extension, a...

Social challenges and supports from the perspective of individuals with Asperger syndrome and other autism spectrum disabilities

Abstract: The study describes the perspectives of individuals with Asperger syndrome and other autism spectrum disabilities (ASDs) regarding social challenges and supports. Eighteen adults with ASDs were individually interviewed. They were asked to describe their experiences navigating their social worlds, and recommend effective social supports and strategies for improving social connectedness. Qualitative analyses of the interview transcripts revealed a number of common experiences including a profound sense of isolation, difficulty initiating social interactions, challenges relating to communication, longing for greater intimacy, desire to contribute to one's community, and effort to develop greater social/self-awareness. Commonly recommended social supports included external supports (e.g. activities based on shared interests, highly structured or scripted social activities, and small groups or dyads); communication supports (e.g. alternative modes of communication, explicit communication, and instruction in interpreting and using social cues); and self-initiated strategies for handling social anxiety (e.g. creative/improvisational outlets, physical activity, spiritual practice/organized religion, and time spent alone).