D-branes on the Quintic

We study D-branes on the quintic CY by combining results from several directions: general results on holomorphic curves and vector bundles, stringy geometry and mirror symmetry, and the boundary states in Gepner models recently constructed by Recknagel and Schomerus, to begin sketching a picture of D-branes in the stringy regime. We also make first steps towards computing superpotentials on the D-brane world-volumes.Comment: harvmac, 78 pp (v3: notes added and improved discussion of an example

Collaborative Approaches to the Sociopolitical Environment: The Emergence of Issues Management Alliances

Increasing turbulence in the sociopolitical environment is reshaping the environmental management strategies employed by business and other institutions. New expectations of the role of business in society, changing demographics, critical social problems such as spiraling health care costs, educational reform and child care, and environmental degradation are posing serious challenges to business organizations and society as a whole. Private, public, and independent sector institutions have initiated a wide variety of collaborative, multi-organizational approaches to issues management which we describe as issues management alliances (IMAs). Known by a myriad of labels such as public-private partnerships, innovating organizations, community development corporations, and self-regulatory agencies, issues management alliances appear to be an adaptive mode of response to a turbulent sociopolitical environment: specifically, they address complex issues and problems that are not being managed adequately by organizations acting alone. To date, however, our understanding of issues management alliances has been fragmented. The primary purpose of this paper is to foster a more systematic appreciation of this robust phenomenon. First, we provide a definition of issues management alliance and organize the disparate examples of IMAs using Cummings\u27 (1984) model of transorganizational systems. Second, we discuss the necessary conditions for the emergence and maintenance of this mode of response in terms of their effectiveness and differential efficiency. Finally, we conclude with a discussion of the implications of this phenomenon

Investigating Habituation to Premonitory Urges in Behavior Therapy for Tic Disorders

Behavior therapy is effective for Persistent Tic Disorders (PTDs), but behavioral processes facilitating tic reduction are not well understood. One process, habituation, is thought to create tic reduction through decreases in premonitory urge severity. The current study tested whether premonitory urges decreased in youth with PTDs (N = 126) and adults with PTDs (N = 122) who participated in parallel randomized clinical trials comparing behavior therapy to psychoeducation and supportive therapy (PST). Trends in premonitory urges, tic severity, and treatment outcome were analyzed according to the predictions of a habituation model, whereby urge severity would be expected to decrease in those who responded to behavior therapy. Although adults who responded to behavior therapy showed a significant trend of declining premonitory urge severity across treatment, results failed to demonstrate that behavior therapy specifically caused changes in premonitory urge severity. In addition, reductions in premonitory urge severity in those who responded to behavior therapy were significant greater than those who did not respond to behavior therapy but no different than those who responded or did not respond to PST. Children with PTDs failed to show any significant changes in premonitory urges. Reductions in premonitory urge severity did not mediate the relationship between treatment and outcome in either adults or children. These results cast doubt on the notion that habituation is the therapeutic process underlying the effectiveness of behavior therapy, which has immediate implications for the psychoeducation and therapeutic rationale presented in clinical practice. Moreover, there may be important developmental changes in premonitory urges in PTDs, and alternative models of therapeutic change warrant investigation

Scanning Tunneling Microscopy Studies of Chloroplasts in Solution

Previous work has shown that it is possible to image whole uncoated chloroplasts using scanning tunneling microscopy (STM), provided this is done in solution using tunnelling currents below about 100 pA. More recent images include some which suggest that the STM is sensitive to dynamic processes occurring on chloroplast surfaces. Current-versus-distance curves and dI/ds measurements are consistent with tunnelling between the tip and sample surface, and relatively small deformations of the sample surface due to tip-sample forces. Attempts to use the same imaging conditions on bacteria were unsuccessful

Monitoring brain activity with protein voltage and calcium sensors

© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 5 (2015): 10212, doi:10.1038/srep10212.Understanding the roles of different cell types in the behaviors generated by neural circuits requires protein indicators that report neural activity with high spatio-temporal resolution. Genetically encoded fluorescent protein (FP) voltage sensors, which optically report the electrical activity in distinct cell populations, are, in principle, ideal candidates. Here we demonstrate that the FP voltage sensor ArcLight reports odor-evoked electrical activity in the in vivo mammalian olfactory bulb in single trials using both wide-field and 2-photon imaging. ArcLight resolved fast odorant-responses in individual glomeruli, and distributed odorant responses across a population of glomeruli. Comparisons between ArcLight and the protein calcium sensors GCaMP3 and GCaMP6f revealed that ArcLight had faster temporal kinetics that more clearly distinguished activity elicited by individual odorant inspirations. In contrast, the signals from both GCaMPs were a saturating integral of activity that returned relatively slowly to the baseline. ArcLight enables optical electrophysiology of mammalian neuronal population activity in vivo.Supported by US NIH DC005259, WCI 2009-003 from the National Research Foundation of Korea, a James Hudson Brown – Alexander Brown Coxe fellowship from Yale University, and a Ruth L. Kirschstein National Research Service Award DC012981

What have we already learned from the CMB?

The COBE satellite, and the DMR experiment in particular, was extraordinarily successful. However, the DMR results were announced about 7 years ago, during which time a great deal more has been learned about anisotropies in the Cosmic Microwave Background (CMB). The CMB experiments currently being designed and built, including long-duration balloons, interferometers, and two space missions, promise to address several fundamental cosmological issues. We present our evaluation of what we already know, what we are beginning to learn now, and what the future may bring.Comment: 20 pages, 3 figures. Changes to match version accepted by PAS