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.

Unveiling pseudospin and angular momentum in photonic graphene

Abstract: Pseudospin, an additional degree of freedom inherent in graphene, plays a key role in understanding many fundamental phenomena such as the anomalous quantum Hall effect, electron chirality and Klein paradox. Unlike the electron spin, the pseudospin was traditionally considered as an unmeasurable quantity, immune to Stern-Gerlach-type experiments. Recently, however, it has been suggested that graphene pseudospin is a real angular momentum that might manifest itself as an observable quantity, but so far direct tests of such a momentum remained unfruitful. Here, by selective excitation of two sublattices of an artificial photonic graphene, we demonstrate pseudospin-mediated vortex generation and topological charge flipping in otherwise uniform optical beams with Bloch momentum traversing through the Dirac points. Corroborated by numerical solutions of the linear massless Dirac-Weyl equation, we show that pseudospin can turn into orbital angular momentum completely, thus upholding the belief that pseudospin is not merely for theoretical elegance but rather physically measurable.

Observation of discrete solitons and soliton rotation in optically induced periodic ring lattices.

Abstract: We report the first experimental demonstration of ring-shaped photonic lattices by optical induction and the formation of discrete solitons in such radially symmetric lattices. The transition from discrete diffraction to single-channel guidance or nonlinear self-trapping of a probe beam is achieved by fine-tuning the lattice potential or the focusing nonlinearity. In addition to solitons trapped in the lattice center and in different lattice rings, we demonstrate controlled soliton rotation in the Bessel-like ring lattices.

Laboratory detection and identification of Aspergillus species by microscopic observation and culture: the traditional approach.

Abstract: Molecular and immunologic tests promise better, faster laboratory diagnosis of aspergillosis, but microscopy and culture remain commonly used and essential tools. Procedural changes, as well as adequate training of laboratory professionals, can enhance the value of these traditional tools. Using Blankophor or Calcofluor for microscopic examinations; improving recognition of morphologic characteristics of opportunistic fungi in stained smears of specimens; maximizing the growth rate and production of conidia by Aspergillus spp. in culture; and recognizing atypical variants of common aspergilli can improve the laboratory's contribution to rapid diagnosis. Surveys indicate that the number of laboratory professionals is declining as the demand for healthcare is rising. Effective recruitment, retention, and training of personnel must be concurrent with advances in technology.

Technology Transfer Offices as Institutional Entrepreneurs: The Case of Wisconsin Alumni Research Foundation and Human Embryonic Stem Cells

Abstract: We highlight the emerging role of technology transfer offices as institutional entrepreneurs involved in building legitimacy for novel technologies. To illustrate this role, we carry out an in-depth study of the Wisconsin Alumni Research Foundation's (WARF) initiatives to support the emergence of human embryonic stem cell (hESC) technology. Our narrative account reveals that WARF took on three sub-roles; that of protector, propagator and influencer of the nascent technology. We highlight how the dual missions of technology transfer offices (TTOs), i.e., their private and societal interests, can influence how they engage in these roles, which in turn can impact the trajectory of the technology. The implications of these findings for the literature on technology transfer, institutional entrepreneurship, and the emergence and evolution of novel technologies are discussed. Copyright 2007 , Oxford University Press.

Internal working models of caregiving and security of attachment at age six

Abstract: This study describes the relation between internal working models of caregiving, child attachment, and maternal behavior in the home. Thirty-two mothers of 6-year-old children were observed in the home and subsequently interviewed regarding experiential and affective dimensions of parenting. Interviews were examined in order to assess the quality of the mother's thinking regarding two dimensions of caregiving (secure base, competence) which we hypothesized to be related to attachment security. Results indicated a strong correspondence between internal working models of caregiving and child mental representations of attachments as measured from the child's response to a laboratory reunion. The correspondence between mental representations of caregiving and maternal behavior in the home was limited. Representation ratings were most strongly associated with competence-supporting behavior. Implications for infant mental health research and program evaluation are discussed.