The evolution of young stellar object disks and their environment

The main efforts were directed towards determining the frequency of disk occurrence and the timescales for disk evolution for solar-type and intermediate mass stars. The results of the investigation showed that optically thick disks are accretion disks. The projected accomplishments are also discussed

An analysis of the peculiar A star HD 204411

Spectrum analysis of cool Ap star HD 20441

Surface-gravity determinations for main-sequence B stars

Astronomical models for computing surface gravity of B stars from hydrogen line equivalent width

The properties and environment of primitive solar nebulae as deduced from observations of solar-type pre-main sequence stars

The following topics were discussed: (1) current observation evidence for the presence of circumstellar disks associated with solar type pre-main sequence (PMS) stars; (2) the properties of such disks; and (3) the disk environment

Bright crater outflows: Possible emplacement mechanisms

Lobate features with a strong backscatter are associated with 43 percent of the impact craters cataloged in Magellan's cycle 1. Their apparent thinness and great lengths are consistent with a low-viscosity material. The longest outflow yet identified is about 600 km in length and flows from the 90-km-diameter crater Addams. There is strong evidence that the outflows are largely composed of impact melt, although the mechanisms of their emplacement are not clearly understood. High temperatures and pressures of target rocks on Venus allow for more melt to be produced than on other terrestrial planets because lower shock pressures are required for melting. The percentage of impact craters with outflows increases with increasing crater diameter. The mean diameter of craters without outflows is 14.4 km, compared with 27.8 km for craters with outflows. No craters smaller than 3 km, 43 percent of craters in the 10- to 30-km-diameter range, and 90 percent in the 80- to 100-km-diameter range have associated bright outflows. More melt is produced in the more energetic impact events that produce larger craters. However, three of the four largest craters have no outflows. We present four possible mechanisms for the emplacement of bright outflows. We believe this 'shotgun' approach is justified because all four mechanisms may indeed have operated to some degree

An ABC transporter containing a forkhead-associated domain interacts with a serine-threonine protein kinase and is required for growth of Mycobacterium tuberculosis in mice

Forkhead-associated (FHA) domains are modular phosphopeptide recognition motifs with a striking preference for phosphothreonine-containing epitopes. FHA domains have been best characterized in eukaryotic signaling pathways but have been identified in six proteins in Mycobacterium tuberculosis, the causative organism of tuberculosis. One of these, coded by gene Rv1747, is an ABC transporter and the only one to contain two such modules. A deletion mutant of Rv1747 is attenuated in a mouse intravenous injection model of tuberculosis where the bacterial load of the mutant is 10-fold lower than that of the wild type in both lungs and spleen. In addition, growth of the mutant in mouse bone marrow-derived macrophages and dendritic cells is significantly impaired. In contrast, growth of this mutant in vitro was indistinguishable from that of the wild type. The mutant phenotype was lost when the mutation was complemented by the wild-type allele, confirming that it was due to mutation of Rv1747. Using yeast two-hybrid analysis, we have shown that the Rv1747 protein interacts with the serine-threonine protein kinase PknF. This interaction appears to be phospho-dependent since it is abrogated in a kinase-dead mutant and by mutations in the presumed activation loop of PknF and in the first FHA domain of Rv1747. These results demonstrate that the protein coded by Rv1747 is required for normal virulent infection by M. tuberculosis in mice and, since it interacts with a serine-threonine protein kinase in a kinase-dependent manner, indicate that it forms part of an important phospho-dependent signaling pathway

Developing Next-Generation Engineers -. IMPACTS

In the development of remote labs and virtual engineering tools the focus has rightly been on the technical challenges to be overcome to provide useful and usable tools and experimentation. However, the utilization of such facilities in educational settings is not simply a case of making students and faculty aware of their existence. In fact, there are significant pedagogical issues in the blending of remote and virtual facilities with cohort and location-based teaching and learning, and a number of research findings have highlighted student issues with both traditional teaching methods and the use of predominantly on-line materials. The authors have considerable experience in the development, production and use of eLearning materials in academic and industrial environments, and in tool virtualization and remote labs, and here propose a model for a distributed Masters program that supports students on a location-neutral basis utilizing online eLearning materials, virtual tools and remote lab facilities, combined with location-specific specialist teaching and learning facilities. The program described is already in operation between three European Universities, with the intention to expand both within Europe and beyond, utilizing the Erasmus Mundus scheme. The program is based on a constructivist pedagogic model that demands considerable independence of study and research on the part of the students, within a rich environment of high-quality specialist materials offered in a wide variety of modes. The authors believe that this approach optimizes the benefits of individual academic specialization in research and teaching, combined with effective use of eLearning materials, remote labs and virtual tools in a distributed environment, and thereby addresses a number of the issues identified from the research while also offering a high quality program to educate and develop next generation Engineers