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.

An Eccentric Hot Jupiter Orbiting the Subgiant HD 185269

Abstract: We report the detection of a Jupiter-mass planet in a 6.838 day orbit around the 1.28 M_☉ subgiant HD 185269. The eccentricity of HD 185269b (e = 0.30) is unusually large compared to other planets within 0.1 AU of their stars. Photometric observations demonstrate that the star is constant to ±0.0001 mag on the radial velocity period, strengthening our interpretation of a planetary companion. This planet was detected as part of our radial velocity survey of evolved stars located on the subgiant branch of the H-R diagram—also known as the Hertzsprung gap. These stars, which have masses between 1.2 and 2.5 M_☉, play an important role in the investigation of the frequency of extrasolar planets as a function of stellar mass.

RAAC: Robust and Auditable Access Control With Multiple Attribute Authorities for Public Cloud Storage

Abstract: Data access control is a challenging issue in public cloud storage systems. Ciphertext-policy attribute-based encryption (CP-ABE) has been adopted as a promising technique to provide flexible, fine-grained, and secure data access control for cloud storage with honest-but-curious cloud servers. However, in the existing CP-ABE schemes, the single attribute authority must execute the time-consuming user legitimacy verification and secret key distribution, and hence, it results in a single-point performance bottleneck when a CP-ABE scheme is adopted in a large-scale cloud storage system. Users may be stuck in the waiting queue for a long period to obtain their secret keys, thereby resulting in low efficiency of the system. Although multi-authority access control schemes have been proposed, these schemes still cannot overcome the drawbacks of single-point bottleneck and low efficiency, due to the fact that each of the authorities still independently manages a disjoint attribute set. In this paper, we propose a novel heterogeneous framework to remove the problem of single-point performance bottleneck and provide a more efficient access control scheme with an auditing mechanism. Our framework employs multiple attribute authorities to share the load of user legitimacy verification. Meanwhile, in our scheme, a central authority is introduced to generate secret keys for legitimacy verified users. Unlike other multi-authority access control schemes, each of the authorities in our scheme manages the whole attribute set individually. To enhance security, we also propose an auditing mechanism to detect which attribute authority has incorrectly or maliciously performed the legitimacy verification procedure. Analysis shows that our system not only guarantees the security requirements but also makes great performance improvement on key generation.

Do people with schizophrenia have difficulty anticipating pleasure, engaging in effortful behavior, or both?

Abstract: Motivation deficits are common in schizophrenia, but little is known about underlying mechanisms, or the specific goals that people with schizophrenia set in daily life. Using neurobiological heuristics of pleasure anticipation and effort assessment, we examined the quality of activities and goals of 47 people with and 41 people without schizophrenia, utilizing ecological momentary assessment. Participants were provided cell phones and called 4 times a day for 7 days, and were asked about their current activities and anticipation of upcoming goals. Activities and goals were later coded by independent raters on pleasure and effort. In line with recent laboratory findings on effort computation deficits in schizophrenia, relative to healthy participants, people with schizophrenia reported engaging in less effortful activities and setting less effortful goals, which were related to patient functioning. In addition, patients showed some inaccuracy in estimating how difficult an effortful goal would be, which in turn was associated with lower neurocognition. In contrast to previous research, people with schizophrenia engaged in activities and set goals that were more pleasure-based, and anticipated goals as being more pleasurable than controls. Thus, this study provided evidence for difficulty with effortful behavior and not anticipation of pleasure. These findings may have psychosocial treatment implications, focusing on effort assessment or effort expenditure. For example, to help people with schizophrenia engage in more meaningful goal pursuits, treatment providers may leverage low-effort pleasurable goals by helping patients to break down larger, more complex goals into smaller, lower-effort steps that are associated with specific pleasurable rewards.

Spatially explicit predictions of blood parasites in a widely distributed African rainforest bird

Abstract:  Critical to the mitigation of parasitic vector-borne diseases is the development of accurate spatial predictions that integrate environmental conditions conducive to pathogen proliferation. Species of Plasmodium and Trypanosoma readily infect humans, and are also common in birds. Here, we develop predictive spatial models for the prevalence of these blood parasites in the olive sunbird (Cyanomitra olivacea). Since this species exhibits high natural parasite prevalence and occupies diverse habitats in tropical Africa, it represents a distinctive ecological model system for studying vector-borne pathogens. We used PCR and microscopy to screen for haematozoa from 28 sites in Central and West Africa. Species distribution models were constructed to associate ground-based and remotely sensed environmental variables with parasite presence. We then used machine-learning algorithm models to identify relationships between parasite prevalence and environmental predictors. Finally, predictive maps were generated by projecting model outputs to geographically unsampled areas. Results indicate that for Plasmodium spp., the maximum temperature of the warmest month was most important in predicting prevalence. For Trypanosoma spp., seasonal canopy moisture variability was the most important predictor. The models presented here visualize gradients of disease prevalence, identify pathogen hotspots and will be instrumental in studying the effects of ecological change on these and other pathogens.