Influence of the upper critical field anisotropy on the transport properties of polycrystalline MgB2_{2}

The intrinsic properties of MgB$_2$ form the basis for all applications of this superconductor. We wish to emphasize that the application range of polycrystalline MgB$_2$ is limited by the upper critical field H$_{c2}$ and its anisotropy. In wires or tapes, the MgB$_2$ grains are randomly oriented or only slightly textured and the anisotropy of the upper critical field leads to different transport properties in different grains, if a magnetic field is applied and the current transport becomes percolative. The irreversibility line is caused by the disappearance of a continuous superconducting current path and not by depinning as in high temperature superconductors. Based on a percolation model, we demonstrate how changes of the upper critical field and its anisotropy and how changes of flux pinning will influence the critical currents of a wire or a tape. These predictions are compared to results of neutron irradiation experiments, where these parameters were changed systematically

What Difference do Bystanders Make? The Association of Bystander Involvement with Victim Outcomes in a Community Sample

Objective: To fill gaps in the bystander literature by describing patterns of bystander involvement and associations between bystander involvement and victim outcomes across different types of emotional, physical, and sexual victimizations and to expand these considerations to a rural rather than urban sample. Method: Adults and adolescents (n = 1,703) were surveyed about bystander actions, bystander safety, and victim outcomes (injury, disrupted routine, fear level, and current mental health) for 10 forms of victimization. Results: Bystanders were present for roughly 2 thirds of most victimization types (59% to 67%), except sexual victimization (17%). Relatives were the most common bystanders of family violence and friends or acquaintances were the most common bystanders of peer violence. For all 10 victimizations, more bystanders helped than harmed the situation, but most commonly had no impact. Rates of bystander harm for sexual victimizations were higher than for other types. Especially for peer-perpetrated incidents, victim outcomes were often better when bystanders helped. Bystander safety (unharmed and unthreatened) was consistently associated with better victim outcomes. Conclusion: Bystanders witness the majority of physical and psychological victimizations. These data lend support to the premise of many prevention programs that helpful bystanders are associated with more positive victim outcomes. Bystander prevention should focus on the type of bystanders most commonly present and should teach bystanders ways to stay safe while helping victims

P19-43. Regulatory T cell epitopes in a dendritic cell-targeted HIV vaccine delivery platform

Poster Presentation from AIDS Vaccine 2009 Paris, France. 19–22 October 200