9,540 research outputs found

    Study of tracking and data acquisition system for the 1990's. Volume 4: TDAS space segment architecture

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    Tracking and data acquisition system (TDAS) requirements, TDAS architectural goals, enhanced TDAS subsystems, constellation and networking options, TDAS spacecraft options, crosslink implementation, baseline TDAS space segment architecture, and treat model development/security analysis are addressed

    Isotopic Study of Siderite Concretion, Tuscarawas County, Ohio

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    Author Institution: Department of Geology and Mineralogy, Ohio State University ; Division of Geological Survey, Ohio Department of Natural Resources, Fountain SquareA carbonate concretion from the shale bed overlying the No. 5 coal of Pennsylvanian age in Tuscarawas County is composed of siderite and contains pyrite, barite, sphalerite and traces of calcite in its interior and in fractures. The siderite has 8I 3C= +0.65%o, Sr=289 ppm and 87Sr/86Sr=0.7110±0.0009- These results indicate that the siderite was deposited from brackish water in the pore spaces of the sediment and discredit the hypothesis that the carbonate ions originated by oxidation of peat or organic material. The barite has 8 S=— 4.6%o, indicating that it was not precipitated from sea water. Pyrite and sphalerite have 8 S= — 10.8%o and — 4.6%o, respectively, and were not deposited in isotopic equilibrium with each other. The sulfur in all three minerals is enriched in l6S as a result of bacterial reduction of sulfate to sulfide

    How do older people describe their sensory experiences of the natural world? a systematic review of the qualitative evidence

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    This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Despite the increased scholarly interest in the senses and sensory experiences, the topic of older people's sensory engagement with nature is currently under researched. This paper reviews and synthesises qualitative research evidence about how older people, including those living with dementia, describe their sensory engagement with the natural world. METHODS: Ten databases were searched from 1990 to September 2014: MEDLINE (Ovid), MEDLINE-in-Process (Ovid), PsycINFO (Ovid), CINAHL (EBSCO), GreenFILE (EBSCO), ProQuest Sociology, ASSIA (ProQuest), International Bibliography of the Social Sciences (ProQuest); HMIC (Ovid); Social Policy and Practice (Ovid). Forward and backward citation chasing of included articles was conducted; 20 organizations were contacted to identify unpublished reports. Screening was undertaken independently by two reviewers. RESULTS: Twenty seven studies were included. Thematic analysis revealed that descriptions of sensory experiences are encompassed within six themes: descriptions from 'the window'; sensory descriptions that emphasise vision; descriptions of 'being in nature'; descriptions of 'doing in nature'; barriers to sensory engagement; and meanings of being and doing in nature. CONCLUSIONS: Older people derive considerable pleasure and enjoyment from viewing nature, being and doing in nature which, in turn has a positive impact on their wellbeing and quality of life. Future research could usefully explore how sensory engagement with nature could be used to stimulate reminiscences of places and people, and evoke past sensory experiences to enrich everyday life and maintain a sense of self. The protocol was registered with PROSPERO ( CRD42015020736 ).The research for this systematic review was supported by the European Centre for Environment and Human Health which is in part financed by the European Regional Development Fund Programme 2007 to 2013 and European Social Fund Convergence for Cornwall and Isles of Scilly. RG is partially supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) for the South West Peninsula

    The relationship between Hippocampal asymmetry and working memory processing in combat-related PTSD: a monozygotic twin study

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    BACKGROUND: PTSD is associated with reduction in hippocampal volume and abnormalities in hippocampal function. Hippocampal asymmetry has received less attention, but potentially could indicate lateralised differences in vulnerability to trauma. The P300 event-related potential component reflects the immediate processing of significant environmental stimuli and has generators in several brain regions including the hippocampus. P300 amplitude is generally reduced in people with PTSD. METHODS: Our study examined hippocampal volume asymmetry and the relationship between hippocampal asymmetry and P300 amplitude in male monozygotic twins discordant for Vietnam combat exposure. Lateralised hippocampal volume and P300 data were obtained from 70 male participants, of whom 12 had PTSD. We were able to compare (1) combat veterans with current PTSD; (2) their non-combat-exposed co-twins; (3) combat veterans without current PTSD and (4) their non-combat-exposed co-twins. RESULTS: There were no significant differences between groups in hippocampal asymmetry. There were no group differences in performance of an auditory oddball target detection task or in P300 amplitude. There was a significant positive correlation between P300 amplitude and the magnitude of hippocampal asymmetry in participants with PTSD. CONCLUSIONS: These findings suggest that greater hippocampal asymmetry in PTSD is associated with a need to allocate more attentional resources when processing significant environmental stimuli.Timothy Hall, Cherrie Galletly, C.R. Clark, Melinda Veltmeyer, Linda J. Metzger, Mark W. Gilbertson, Scott P. Orr, Roger K. Pitman and Alexander McFarlan

    Monotonicity of Fitness Landscapes and Mutation Rate Control

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    A common view in evolutionary biology is that mutation rates are minimised. However, studies in combinatorial optimisation and search have shown a clear advantage of using variable mutation rates as a control parameter to optimise the performance of evolutionary algorithms. Much biological theory in this area is based on Ronald Fisher's work, who used Euclidean geometry to study the relation between mutation size and expected fitness of the offspring in infinite phenotypic spaces. Here we reconsider this theory based on the alternative geometry of discrete and finite spaces of DNA sequences. First, we consider the geometric case of fitness being isomorphic to distance from an optimum, and show how problems of optimal mutation rate control can be solved exactly or approximately depending on additional constraints of the problem. Then we consider the general case of fitness communicating only partial information about the distance. We define weak monotonicity of fitness landscapes and prove that this property holds in all landscapes that are continuous and open at the optimum. This theoretical result motivates our hypothesis that optimal mutation rate functions in such landscapes will increase when fitness decreases in some neighbourhood of an optimum, resembling the control functions derived in the geometric case. We test this hypothesis experimentally by analysing approximately optimal mutation rate control functions in 115 complete landscapes of binding scores between DNA sequences and transcription factors. Our findings support the hypothesis and find that the increase of mutation rate is more rapid in landscapes that are less monotonic (more rugged). We discuss the relevance of these findings to living organisms

    Patterns of Interactions in Complex Social Networks Based on Coloured Motifs Analysis

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    Coloured network motifs are small subgraphs that enable to discover and interpret the patterns of interaction within the complex networks. The analysis of three-nodes motifs where the colour of the node reflects its high – white node or low – black node centrality in the social network is presented in the paper. The importance of the vertices is assessed by utilizing two measures: degree prestige and degree centrality. The distribution of motifs in these two cases is compared to mine the interconnection patterns between nodes. The analysis is performed on the social network derived from email communication

    Processing and Transmission of Information

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    Contains reports on three research projects.National Aeronautics and Space Administration (Grant NGL-22-009-013)Joint Services Electronics Programs (U.S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E

    Urine drug screening in chronic pain management

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    This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of urine drug screening in chronic pain management

    Processing and Transmission of Information

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    Contains reports on four research projects.National Aeronautics and Space Administration (Grant NGL 22-009-013
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