Nucleation of small silicon carbide dust clusters in AGB stars

Silicon carbide (SiC) grains are a major dust component in carbon-rich AGB stars. The formation pathways of these grains are, however, not fully understood.\ We calculate ground states and energetically low-lying structures of (SiC)$_n$, $n=1,16$ clusters by means of simulated annealing (SA) and Monte Carlo simulations of seed structures and subsequent quantum-mechanical calculations on the density functional level of theory. We derive the infrared (IR) spectra of these clusters and compare the IR signatures to observational and laboratory data.\ According to energetic considerations, we evaluate the viability of SiC cluster growth at several densities and temperatures, characterising various locations and evolutionary states in circumstellar envelopes.\ We discover new, energetically low-lying structures for Si$_{4}$C$_{4}$, Si$_{5}$C$_{5}$, Si$_{15}$C$_{15}$ and Si$_{16}$C$_{16}$, and new ground states for Si$_{10}$C$_{10}$ and Si$_{15}$C$_{15}$. The clusters with carbon-segregated substructures tend to be more stable by 4-9 eV than their bulk-like isomers with alternating Si-C bonds. However, we find ground states with cage ("bucky"-like) geometries for Si$_{12}$C$_{12}$ and Si$_{16}$C$_{16}$ and low-lying, stable cage structures for n $\ge$ 12. The latter findings indicate thus a regime of clusters sizes that differs from small clusters as well as from large-scale crystals. Thus, and owing to their stability and geometry, the latter clusters may mark a transition from a quantum-confined cluster regime to crystalline, solid bulk-material. The calculated vibrational IR spectra of the ground-state SiC clusters shows significant emission. They include the 10-13 $\mu$m wavelength range and the 11.3 $\mu$m feature inferred from laboratory measurements and observations, respectively, though the overall intensities are rather low.Comment: 16 pages, 25 figures, 3 tables, accepted for publication in Ap

agINFRA - where agriculture, biodiversity and information technology meet

This poster will provide a brief introduction to and overview of the agINFRA project, a research infrastructure project funded by the EU. The project is developing a data infrastructure to support agricultural scientific communities through promoting data sharing and the development of trust in agricultural sciences. Members of the project are working to provide tools, hosted in a scientific gateway, for creating a linked open data environment for agricultural scientists. The project will try to remove existing obstacles concerning open access to scientific information (including discovery and use of the data) in agriculture. The project consortium also seeks to improve the preparedness of the agricultural scientific community to face, manage and exploit the abundance of relevant data that is (or will become) available to agricultural researchers as data becomes more openly available. It is intended that the project will promote research on food and agriculture, including research to adapt to, and mitigate climate change, and access to research results and technologies at national, regional and international levels. The overall aim of the project being to improve access to knowledge by creating a high level of interoperability between agricultural and other data resources

The Vanishing Sociology-Social Work Alliance: A Study in the Politics of Professionalism

The undergraduate sociology-social work alliance in sociology departments has a long tradition in American colleges despite ideological differences between the two disciplines. Recently this old alliance shows signs of disintegration. This paper argues that the recent emphasis on professionalization of undergraduate social work through the use of accrediting standards coupled with the control of Federal social work training grants have placed new pressures on the old alliance. Evidence is presented which indicates that the conflict is being resolved in the direction of greater administrative specialization and autonomy for social work

The Challenge of the Future

Commencement address given by D. Allan Bromley, Director of the White House Office of Science and Technology and Chair of the President's Council of Science and Technology, to the Winter 1991 graduating class of The Ohio State University, St. John Arena, Columbus, Ohio, March 22, 1991

The Trypanosoma cruzi enzyme TcGPXI is a glycosomal peroxidase and can be linked to trypanothione reduction by glutathione or tryparedoxin.

Trypanosoma cruzi glutathione-dependent peroxidase I (TcGPXI) can reduce fatty acid, phospholipid, and short chain organic hydroperoxides utilizing a novel redox cycle in which enzyme activity is linked to the reduction of trypanothione, a parasite-specific thiol, by glutathione. Here we show that TcGPXI activity can also be linked to trypanothione reduction by an alternative pathway involving the thioredoxin-like protein tryparedoxin. The presence of this new pathway was first detected using dialyzed soluble fractions of parasite extract. Tryparedoxin was identified as the intermediate molecule following purification, sequence analysis, antibody studies, and reconstitution of the redox cycle in vitro. The system can be readily saturated by trypanothione, the rate-limiting step being the interaction of trypanothione with the tryparedoxin. Both tryparedoxin and TcGPXI operate by a ping-pong mechanism. Overexpression of TcGPXI in transfected parasites confers increased resistance to exogenous hydroperoxides. TcGPXI contains a carboxyl-terminal tripeptide (ARI) that could act as a targeting signal for the glycosome, a kinetoplastid-specific organelle. Using immunofluorescence, tagged fluorescent proteins, and biochemical fractionation, we have demonstrated that TcGPXI is localized to both the glycosome and the cytosol. The ability of TcGPXI to use alternative electron donors may reflect their availability at the corresponding subcellular sites

How Do Communities Use a Participatory Public Health Approach to Build Resilience? The Los Angeles County Community Disaster Resilience Project.

Community resilience is a key concept in the National Health Security Strategy that emphasizes development of multi-sector partnerships and equity through community engagement. Here, we describe the advancement of CR principles through community participatory methods in the Los Angeles County Community Disaster Resilience (LACCDR) initiative. LACCDR, an initiative led by the Los Angeles County Department of Public Health with academic partners, randomized 16 community coalitions to implement either an Enhanced Standard Preparedness or Community Resilience approach over 24 months. Facilitated by a public health nurse or community educator, coalitions comprised government agencies, community-focused organizations and community members. We used thematic analysis of data from focus groups (n = 5) and interviews (n = 6 coalition members; n = 16 facilitators) to compare coalitions' strategies for operationalizing community resilience levers of change (engagement, partnership, self-sufficiency, education). We find that strategies that included bidirectional learning helped coalitions understand and adopt resilience principles. Strategies that operationalized community resilience levers in mutually reinforcing ways (e.g., disseminating information while strengthening partnerships) also secured commitment to resilience principles. We review additional challenges and successes in achieving cross-sector collaboration and engaging at-risk groups in the resilience versus preparedness coalitions. The LACCDR example can inform strategies for uptake and implementation of community resilience and uptake of the resilience concept and methods

Hypernetwork-based peer marking for scalable certificated mass education

In the context of the need for massive free education for the Complex Systems Society and the UNESCO Complex Systems Digital Campus, scalable methods are essential for assessing tens of thousands of students’ work for certification. Automated marking is a partial solution but has many drawbacks. Peer marking, where students mark each others’ assignments, is a scalable solution since every extra student is an extra marker. However there are concerns about the quality of peer marking, since some students may not be competent to mark the work of others. Some students are better than others and often the best students are well qualified to assess the work of their peers. To make peer marking high quality we are using new hypernetwork-based methods to extend previous methods to discover which students are good markers and which students are less good as a course progresses

IL-23 Induces Atopic Dermatitis-Like Inflammation Instead of Psoriasis-Like Inflammation in CCR2-Deficient Mice

Psoriasis is an immune-mediated chronic inflammatory skin disease, characterized by epidermal hyperplasia and infiltration of leukocytes into the dermis and epidermis. IL-23 is expressed in psoriatic skin, and IL-23 injected into the skin of mice produces IL-22-dependent dermal inflammation and acanthosis. The chemokine receptor CCR2 has been implicated in the pathogenesis of several inflammatory diseases, including psoriasis. CCR2-positive cells and the CCR2 ligand, CCL2 are abundant in psoriatic lesions. To examine the requirement of CCR2 in the development of IL-23-induced cutaneous inflammation, we injected the ears of wild-type (WT) and CCR2-deficient (CCR2−/−) mice with IL-23. CCR2−/− mice had increased ear swelling and epidermal thickening, which was correlated with increased cutaneous IL-4 levels and increased numbers of eosinophils within the skin. In addition, TSLP, a cytokine known to promote and amplify T helper cell type 2 (Th2) immune responses, was also increased within the inflamed skin of CCR2−/− mice. Our data suggest that increased levels of TSLP in CCR2−/− mice may contribute to the propensity of these mice to develop increased Th2-type immune responses

Recurrent depression and relational trauma: a single case of memory processing

Cognitive behavioural therapy (CBT) is an effective treatment for depression, but a significant minority of clients are difficult to treat, including those with histories of relational trauma. The model of Beck et al. (1979) proposes that adverse childhood experiences lead to negative core beliefs, and these create a susceptibility to depression. However, Beck’s model does not identify trauma as a subset of adverse experiences. An alternative view is that traumatised clients internalise conflicting representations of self and it is conflict, interacting with trauma memories, that creates a vulnerability for depression. In this formulation, methods from the treatment of post-traumatic stress disorder (PTSD) could be incorporated into the treatment of depression, to emotionally process trauma memories and resolve self-identity conflicts. The aims of this study were to: (1) report the treatment of a 67-year-old man with recurrent depression and a history of prolonged relational trauma, and (2) to explore how memory processing from the treatment of PTSD can be incorporated into the treatment of recurrent depression. A single case observational design was used in the long-term treatment of a depressed traumatised client. The client received 47 individual sessions over 19 months in routine clinical practice in a tertiary CBT service. He completed repeated measures of mood, memory intrusions and sleep disruption. The client responded well to treatment with clinically significant improvements across measures of mood, memory and sleep. The effects were sustained over an 18-month follow-up. Memory processing was successfully integrated into a high-intensity treatment for recurrent depression. This is a promising approach for depressed clients with histories of relational trauma