Magic Islands and Barriers to Attachment: A Si/Si(111)7x7 Growth Model

Surface reconstructions can drastically modify growth kinetics during initial stages of epitaxial growth as well as during the process of surface equilibration after termination of growth. We investigate the effect of activation barriers hindering attachment of material to existing islands on the density and size distribution of islands in a model of homoepitaxial growth on Si(111)7x7 reconstructed surface. An unusual distribution of island sizes peaked around "magic" sizes and a steep dependence of the island density on the growth rate are observed. "Magic" islands (of a different shape as compared to those obtained during growth) are observed also during surface equilibration.Comment: 4 pages including 5 figures, REVTeX, submitted to Physical Review

Simultaneous Genome-Wide Inference of Physical, Genetic, Regulatory, and Functional Pathway Components

Biomolecular pathways are built from diverse types of pairwise interactions, ranging from physical protein-protein interactions and modifications to indirect regulatory relationships. One goal of systems biology is to bridge three aspects of this complexity: the growing body of high-throughput data assaying these interactions; the specific interactions in which individual genes participate; and the genome-wide patterns of interactions in a system of interest. Here, we describe methodology for simultaneously predicting specific types of biomolecular interactions using high-throughput genomic data. This results in a comprehensive compendium of whole-genome networks for yeast, derived from ∼3,500 experimental conditions and describing 30 interaction types, which range from general (e.g. physical or regulatory) to specific (e.g. phosphorylation or transcriptional regulation). We used these networks to investigate molecular pathways in carbon metabolism and cellular transport, proposing a novel connection between glycogen breakdown and glucose utilization supported by recent publications. Additionally, 14 specific predicted interactions in DNA topological change and protein biosynthesis were experimentally validated. We analyzed the systems-level network features within all interactomes, verifying the presence of small-world properties and enrichment for recurring network motifs. This compendium of physical, synthetic, regulatory, and functional interaction networks has been made publicly available through an interactive web interface for investigators to utilize in future research at http://function.princeton.edu/bioweaver/

'I know it's bad for me and yet I do it': exploring the factors that perpetuate smoking in Aboriginal Health Workers - a qualitative study

Extent: 12p. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1472-6963/12/102BACKGROUND Aboriginal Health Workers (AHWs) have a mandate to deliver smoking cessation support to Aboriginal people. However, a high proportion of AHWs are smokers and this undermines their delivery of smoking cessation programs. Smoking tobacco is the leading contributor to the burden of disease in Aboriginal Australians and must be prevented. Little is known about how to enable AHWs to quit smoking. An understanding of the factors that perpetuate smoking in AHWs is needed to inform the development of culturally relevant programs that enable AHWs to quit smoking. A reduction of smoking in AHWs is important to promote their health and also optimise the delivery of smoking cessation support to Aboriginal clients. METHODS We conducted a fundamental qualitative description study that was nested within a larger mixed method participatory research project. The individual and contextual factors that directly or indirectly promote (i.e. perpetuate) smoking behaviours in AHWs were explored in 34 interviews and 3 focus groups. AHWs, other health service staff and tobacco control personnel shared their perspectives. Data analysis was performed using a qualitative content analysis approach with collective member checking by AHW representatives. RESULTS AHWs were highly stressed, burdened by their responsibilities, felt powerless and undervalued, and used smoking to cope with and support a sense of social connectedness in their lives. Factors directly and indirectly associated with smoking were reported at six levels of behavioural influence: personal factors (e.g. stress, nicotine addiction), family (e.g. breakdown of family dynamics, grief and loss), interpersonal processes (e.g. socialisation and connection, domestic disputes), the health service (e.g. job insecurity and financial insecurity, demanding work), the community (e.g. racism, social disadvantage) and policy (e.g. short term and insecure funding). CONCLUSIONS An extensive array of factors perpetuated smoking in AHWs. The multitude of personal, social and environmental stressors faced by AHWs and the accepted use of communal smoking to facilitate socialisation and connection were primary drivers of smoking in AHWs in addition to nicotine dependence. Culturally sensitive multidimensional smoking cessation programs that address these factors and can be tailored to local needs are indicated.Anna P Dawson, Margaret Cargo, Harold Stewart, Alwin Chong and Mark Danie

Perspectives on learning symbolic data with connectionistic systems

Hammer B. Perspectives on learning symbolic data with connectionistic systems. In: Kühn R, Menzel R, Menzel W, Ratsch U, Richter MM, Stamatescu I, eds. Adaptivity and Learning. Berlin: Springer; 2003: 141-160