3,814 research outputs found

    AdS Strings with Torsion: Non-complex Heterotic Compactifications

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    Combining the effects of fluxes and gaugino condensation in heterotic supergravity, we use a ten-dimensional approach to find a new class of four-dimensional supersymmetric AdS compactifications on almost-Hermitian manifolds of SU(3) structure. Computation of the torsion allows a classification of the internal geometry, which for a particular combination of fluxes and condensate, is nearly Kahler. We argue that all moduli are fixed, and we show that the Kahler potential and superpotential proposed in the literature yield the correct AdS radius. In the nearly Kahler case, we are able to solve the H Bianchi using a nonstandard embedding. Finally, we point out subtleties in deriving the effective superpotential and understanding the heterotic supergravity in the presence of a gaugino condensate.Comment: 42 pages; v2. added refs, revised discussion of Bianchi for N

    A 10 kDa polypeptide associated with the oxygen-evolving complex of photosystem II has a putative C-terminal non-cleavable thylakoid transfer domain

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    AbstractThe N-terminal amino acid sequence of the 10 kDa polypeptide associated with the oxygen-evolving complex of wheat photosystem II has been determined and shown to be homologous to the amino acid sequence of the product of the ST-LS1 gene from potato. The N-terminal sequence of the mature protein indicates that the polypeptide is synthesized with a 39 amino acid N-terminal presequence which is similar to chloroplast import sequences but which lacks a hydrophobic domain for transfer of the protein across the thylakoid membrane. The mature polypeptide has a C-terminal hydrophobic region which shows homology to the hydrophobic thylakoid transfer domain of other lumenal proteins and this hydrophobic region of the 10 kDa polypeptide is suggested to facilitate transfer of the protein across the thylakoid membrane

    Sleep hygiene intervention for youth aged 10 to 18 years with problematic sleep: a before-after pilot study

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    BACKGROUND: The current study aimed to examine the changes following a sleep hygiene intervention on sleep hygiene practices, sleep quality, and daytime symptoms in youth. METHODS: Participants aged 10–18 years with self-identified sleep problems completed our age-appropriate F.E.R.R.E.T (an acronym for the categories of Food, Emotions, Routine, Restrict, Environment and Timing) sleep hygiene programme; each category has three simple rules to encourage good sleep. Participants (and parents as appropriate) completed the Adolescent Sleep Hygiene Scale (ASHS), Pittsburgh Sleep Quality Index (PSQI), Sleep Disturbance Scale for Children (SDSC), Pediatric Daytime Sleepiness Scale (PDSS), and wore Actical® monitors twice before (1 and 2 weeks) and three times after (6, 12 and 20 weeks) the intervention. Anthropometric data were collected two weeks before and 20 weeks post-intervention. RESULTS: Thirty-three youths (mean age 12.9 years; M/F = 0.8) enrolled, and retention was 100%. ASHS scores significantly improved (p = 0.005) from a baseline mean (SD) of 4.70 (0.41) to 4.95 (0.31) post-intervention, as did PSQI scores [7.47 (2.43) to 4.47 (2.37); p < 0.001] and SDSC scores [53.4 (9.0) to 39.2 (9.2); p < 0.001]. PDSS scores improved from a baseline of 16.5 (6.0) to 11.3 (6.0) post- intervention (p < 0.001). BMI z-scores with a baseline of 0.79 (1.18) decreased significantly (p = 0.001) post-intervention to 0.66 (1.19). Despite these improvements, sleep duration as estimated by Actical accelerometry did not change. There was however a significant decrease in daytime sedentary/light energy expenditure. CONCLUSIONS: Our findings suggest the F.E.R.R.E.T sleep hygiene education programme might be effective in improving sleep in children and adolescents. However because this was a before and after study and a pilot study with several limitations, the findings need to be addressed with caution, and would need to be replicated within a randomised controlled trial to prove efficacy. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN1261200064981

    Statistical Computations with AstroGrid and the Grid

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    We outline our first steps towards marrying two new and emerging technologies; the Virtual Observatory (e.g, AstroGrid) and the computational grid. We discuss the construction of VOTechBroker, which is a modular software tool designed to abstract the tasks of submission and management of a large number of computational jobs to a distributed computer system. The broker will also interact with the AstroGrid workflow and MySpace environments. We present our planned usage of the VOTechBroker in computing a huge number of n-point correlation functions from the SDSS, as well as fitting over a million CMBfast models to the WMAP data.Comment: Invited talk to appear in "Proceedings of PHYSTAT05: Statistical Problems in Particle Physics, Astrophysics and Cosmology

    Injury severity analysis of accidents involving young male drivers in Great Britain

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    Young male drivers are over-represented in traffic accidents; they were involved in 14% of fatal accidents from 1991 to 2003 while holding only 8% of all drivers licenses in the UK. In this study, a subset of the UK national road accident data from 1991 to 2003 has been analyzed. The primary aim is to determine how to best use monetary and progressive resources to understand how road safety measures will reduce the severity of accidents involving young male drivers in both London and Great Britain. Method: Ordered probit models were used to identify specific accident characteristics that increase the likelihood of one of three categorical outcomes of accident severity: slight, serious, or fatal. Results: Characteristics found to lead to a higher likelihood of serious and fatal injuries are generally similar across Great Britain and London but are different from those predicted to lead to a higher likelihood of slight injuries. Those characteristics predicted to lead to serious and fatal injuries include driving in darkness, between Friday and Sunday, on roads with a speed limit of 60 mph, on single carriageways, overtaking, skidding, hitting an object off the carriageway, and when passing the site of a previous accident. Characteristics predicted to lead to slight injuries include driving in daylight, between Monday and Thursday, on roads with a speed limit of 30 mph or less, at a roundabout, waiting to move, and when an animal is on the carriageway. Impact on Industry: These results aid the selection of policy options that are most likely to reduce the severity of accidents involving young male drivers

    Linking Heterogeneous Biodiversity Information Systems on the GRID: the GRAB Prototype

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    In the field of biodiversity informatics a wide range of diverse databases and tools already exists. The challenge is to integrate such resources in order to support scientists wishing to explore complex problems of relevance to biodiversity, and to create new resources where necessary. In this paper we outline the relevance of biodiversity informatics requirements to the future development of the GRID, identifying the main issues that need to be addressed in this area. We present GRAB (GRid And Biodiversity), which is a prototype demonstrator illustrating how one particular biodiversity-related task, namely bioclimatic modelling, can be supported in a Globus-based environment. We also describe a much larger-scale GRID application project that is just commencing (BiodiversityWorld) in which a flexible problem-solving environment is to be built for full-scale investigations by scientists working in a number of biodiversity research areas

    Neural responses to facial and vocal expressions of fear and disgust

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    Neuropsychological studies report more impaired responses to facial expressions of fear than disgust in people with amygdala lesions, and vice versa in people with Huntington's disease. Experiments using functional magnetic resonance imaging (fMRI) have confirmed the role of the amygdala in the response to fearful faces and have implicated the anterior insula in the response to facial expressions of disgust. We used fMRI to extend these studies to the perception of fear and disgust from both facial and vocal expressions. Consistent with neuropsychological findings, both types of fearful stimuli activated the amygdala. Facial expressions of disgust activated the anterior insula and the caudate-putamen; vocal expressions of disgust did not significantly activate either of these regions. All four types of stimuli activated the superior temporal gyrus. Our findings therefore (i) support the differential localization of the neural substrates of fear and disgust; (ii) confirm the involvement of the amygdala in the emotion of fear, whether evoked by facial or vocal expressions; (iii) confirm the involvement of the anterior insula and the striatum in reactions to facial expressions of disgust; and (iv) suggest a possible general role for the perception of emotional expressions for the superior temporal gyrus
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