ENVIRONMENTAL RISK AND AGRI-ENVIRONMENTAL POLICY DESIGN

Agricultural nonpoint pollution is inherently stochastic (e.g., due to weather). In theory, this randomness has implications for the choice and design of policy instruments. However, very few empirical studies have modeled natural variability. This paper investigates the importance of stochastic processes for the choice and design of alternative nonpoint instruments. The findings suggest that not explicitly considering the stochastic processes in the analysis can produce significantly biased results.Agricultural and Food Policy, Environmental Economics and Policy,

Factors that Contribute to Resident Teaching Effectiveness

Background One of the key components of residency training is to become an educator. Resident physicians teach students, advanced practice providers, nurses, and even faculty on a daily basis. Objective The goal of this study was to identify the objective characteristics of residents, which correlate with perceived overall teaching effectiveness. Methods We conducted a one-year, retrospective study to identify factors that were associated with higher resident teaching evaluations. Senior emergency medicine (EM) teaching residents are evaluated by medical students following clinical teaching shifts. Eighteen factors pertaining to resident teaching effectiveness were chosen. Two items from the medical students' evaluations were analyzed against each factor: teaching effectiveness was measured on a five-point Likert scale and an overall teaching score (1-75). Results A total of 46 EM residents and 843 medical student evaluations were analyzed. The ACGME milestones for systems-based practice (p = 0.02) and accountability (p = 0.05) showed a statistically significant association with a rating of "five" on the Likert scale for teaching effectiveness. Three other ACGME milestones, systems-based practice (p = 0.01), task switching (p = 0.04), and team management (p = 0.03) also showed a statically significant association of receiving a score of 70 or greater on the overall teaching score. Conclusion Residents with higher performance associated with system management and accountability were perceived as highly effective teachers. USMLE and in-service exams were not predictive of higher teaching evaluations. Our data also suggest that effective teachers are working in both academic and community settings, providing a potential resource to academic departments and institutions

Closed Quasi-Fuchsian Surfaces In Hyperbolic Knot Complements

We show that every hyperbolic knot complement contains a closed quasi-Fuchsian surface.Comment: 69 pages, 27 figures. Made small changes suggested by refere

Enhancement of thrust reverser cascade performance using aerodynamic and structural integration

This paper focuses on the design of a cascade within a cold stream thrust reverser during the early, conceptual stage of the product development process. A reliable procedure is developed for the exchange of geometric and load data between a two dimensional aerodynamic model and a three dimensional structural model. Aerodynamic and structural simulations are carried out using realistic operating conditions, for three different design configurations with a view to minimising weight for equivalent or improved aerodynamic and structural performance. For normal operational conditions the simulations show that total reverse thrust is unaffected when the performance of the deformed vanes is compared to the un-deformed case. This shows that for the conditions tested, the minimal deformation of the cascade vanes has no significant affect on aerodynamic efficiency and that there is scope for reducing the weight of the cascade. The pressure distribution through a two dimensional thrust reverser section is determined for two additional cascade vane configurations and it is shown that with a small decrease in total reverse thrust, it is possible to reduce weight and eliminate supersonic flow regimes through the nacelle section. By increasing vane sections in high pressure areas and decreasing sections in low pressure areas the structural performance of the cascade vanes in the weight reduced designs, is improved with significantly reduced levels of vane displacement and stress

Photoreceptor Inner Segment Morphology in Best Vitelliform Macular Dystrophy

PURPOSE To characterize outer retina structure in best vitelliform macular dystrophy (BVMD) and to determine the effect of macular lesions on overlying and adjacent photoreceptors. METHODS Five individuals with BVMD were followed prospectively with spectral domain optical coherence tomography and confocal and nonconfocal split-detector adaptive optics scanning light ophthalmoscopy (AOSLO). The AOSLO cone photoreceptor mosaic images were obtained within and around retinal lesions. Cone density was measured inside and outside lesions. In 2 subjects, densities were compared with published measurements acquired ∼2.5 years before. One subject was imaged 3 times over a 5-month period. RESULTS The AOSLO imaging demonstrated that photoreceptor morphology within BVMD retinal lesions was highly variable depending on the disease stage, with photoreceptor structure present even in advanced disease. The AOSLO imaging was repeatable even in severe disease over short-time and long-time intervals. Photoreceptor density was normal in retinal areas immediately adjacent to lesions and stable over ∼2.5 years. Mobile disk-like structures possibly representing subretinal macrophages were also observed. CONCLUSION Combined confocal and nonconfocal split-detector AOSLO imaging reveals substantial variability within clinical lesions in all stages of BVMD. Longitudinal cellular photoreceptor imaging could prove a powerful tool for understanding disease progression and monitoring emerging therapeutic treatment response in inherited degenerations such as BVMD

The Impacts of Wind Speed Trends and 30-Year Variability in Relation to Hydroelectric Reservoir Inflows on Wind Power in the Pacific Northwest

In hydroelectric dominated systems, the value and benefits of energy are higher during extended dry periods and lower during extended or extreme wet periods. By accounting for regional and temporal differences in the relationship between wind speed and reservoir inflow behavior during wind farm site selection, the benefits of energy diversification can be maximized. The goal of this work was to help maximize the value of wind power by quantifying the long-term (30-year) relationships between wind speed and streamflow behavior, using British Columbia (BC) and the Pacific Northwest (PNW) as a case study. Clean energy and self-sufficiency policies in British BC make the benefits of increased generation during low streamflow periods particularly large. Wind density (WD) estimates from a height of 10m (North American Regional Reanalysis, NARR) were correlated with cumulative usable inflows (CUI) for BC (collected from BC Hydro) for 1979–2010. The strongest WD-CUI correlations were found along the US coast (r ~0.55), whereas generally weaker correlations were found in northern regions, with negative correlations (r ~ -0.25) along BC’s North Coast. Furthermore, during the lowest inflow years, WD anomalies increased by up to 40% above average values for the North Coast. Seasonally, high flows during the spring freshet were coincident with widespread negative WD anomalies, with a similar but opposite pattern for low inflow winter months. These poorly or negatively correlated sites could have a moderating influence on climate related variability in provincial electricity supply, by producing greater than average generation in low inflow years and reduced generation in wet years. Wind speed and WD trends were also analyzed for all NARR grid locations, which showed statistically significant positive trends for most of the PNW and the largest increases along the Pacific Coast

Size of Fireballs Created in High Energy Lead-Lead Collisions as Inferred from Coulomb Distortions of Pion Spectra

We compute the Coulomb effects produced by an expanding, highly charged fireball on the momentum distribution of pions. We compare our results to data on Au+Au at 11.6 A GeV from E866 at the BNL AGS and to data on Pb+Pb at 158 A GeV from NA44 at the CERN SPS. We conclude that the distortion of the spectra at low transverse momentum and mid-rapidity can be explained in both experiments by the effect of the large amount of participating charge in the central rapidity region. By adjusting the fireball expansion velocity to match the average transverse momentum of protons, we find a best fit when the fireball radius is about 10 fm, as determined by the moment when the pions undergo their last scattering. This value is common to both the AGS and CERN experiments.Comment: Enlarged discussion, new references added, includes new analysis of pi-/pi+ at AGS energies. 12 pages 5 figures, uses LaTex and epsfi

The Role of MAPK and SCF in the Destruction of Med13 in Cyclin C Mediated Cell Death

In response to stress, the yeast1 and mammalian2 cyclin C translocate from the nucleus to the cytoplasm, where it associates with the GTPase Drp1/Dnm1 to drive mitochondrial fragmentation and apoptosis. Therefore, the decision to release cyclin C represents a key life or death decision. In unstressed cells, the cyclin C‐Cdk8 kinase regulates transcription by associating with the Mediator of RNA polymerase II. We previously reported that the Mediator component Med13 anchors cyclin C in the nucleus3. Loss of Med13 function leads to constitutive cytoplasmic localization of cyclin C, resulting in fragmented mitochondria, hypersensitivity to stress and mitochondrial dysfunction due to loss of mtDNA. Recently we showed that this molecular switch operates in a two-step process

Latent Period and Transmission of “Candidatus Liberibacter solanacearum” by the Potato Psyllid Bactericera cockerelli (Hemiptera: Triozidae)

"Candidatus Liberibacter solanacearum" (Lso) is an economically important pathogen of solanaceous crops and the putative causal agent of zebra chip disease of potato (Solanum tuberosum L.). This pathogen is transmitted to solanaceous species by the potato psyllid, Bactericera cockerelli (Šulc), but many aspects of the acquisition and transmission processes have yet to be elucidated. The present study was conducted to assess the interacting effects of acquisition access period, incubation period, and host plant on Lso titer in psyllids, the movement of Lso from the alimentary canal to the salivary glands of the insect, and the ability of psyllids to transmit Lso to non-infected host plants. Following initial pathogen acquisition, the probability of Lso presence in the alimentary canal remained constant from 0 to 3 weeks, but the probability of Lso being present in the salivary glands increased with increasing incubation period. Lso copy numbers in psyllids peaked two weeks after the initial pathogen acquisition and psyllids were capable of transmitting Lso to non-infected host plants only after a two-week incubation period. Psyllid infectivity was associated with colonization of insect salivary glands by Lso and with Lso copy numbers >10,000 per psyllid. Results of our study indicate that Lso requires a two-week latent period in potato psyllids and suggest that acquisition and transmission of Lso by psyllids follows a pattern consistent with a propagative, circulative, and persistent mode of transmission