1,386 research outputs found

    Energy efficient engine: Flight propulsion system preliminary analysis and design

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    The characteristics of an advanced flight propulsion system (FPS), suitable for introduction in the late 1980's to early 1990's, was more fully defined. It was determined that all goals for efficiency, environmental considerations, and economics could be met or exceeded with the possible exception of NOx emission. In evaluating the FPS, all aspects were considered including component design, performance, weight, initial cost, maintenance cost, engine system integration (including nacelle), and aircraft integration considerations. The current FPS installed specific fuel consumption was reduced 14.2% from that of the CF6-50C reference engine. When integrated into an advanced, subsonic, study transport, the FPS produced a fuel burn savings of 15 to 23% and a direct operating cost reduction of 5 to 12% depending on the mission and study aircraft characteristics relative to the reference engine

    Characteristics associated with initiation of hormone replacement therapy among Finnish women : A register-linkage study

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    Objective: To investigate which patient characteristics are associated with the initiation of hormone replacement therapy (HRT) in a cohort of Finnish women. Study design: Responses to postal questionnaires distributed to a nationwide, randomly selected cohort of women in 1998, 2000, 2003, 2005 and 2010 were analyzed. The cohort members were aged 40-44 years at the beginning of the study. Information on hormone replacement therapy was received from the national prescription register. Women who started taking HRT between January 1, 1999 and December 31, 2011 were included and previous users were excluded from the analysis. Main outcome measures: Initiation of HRT was the main outcome measure. The following explanatory factors for predicting the use of HRT were examined: sociodemographic factors, personality, health behavior, physiological and mental symptoms, chronic diseases and use of psychopharmaceuticals. The associations between starting HRT and the explanatory factors were analyzed with single-predictor and multi-predictor logistic regression models. Results: Factors predicting that a woman would start taking HRT were: living with a partner, weak sense of coherence, BMI less than 30 kg/m(2), heavy or moderate alcohol use, symptoms of hyperactivity of the sympathetic nervous system, climacteric symptoms and use of psychopharmaceuticals. Conclusions: Women with a good sense of coherence can cope with climacteric symptoms without resorting to HRT. Clinicians need to bear in mind the burden of menopausal symptoms on a woman's personal and working life when HRT is being considered. (C) 2016 Elsevier Ireland Ltd. All rights reserved.Peer reviewe

    Dimension (in)equalities and H\"older continuous curves in fractal percolation

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    We relate various concepts of fractal dimension of the limiting set C in fractal percolation to the dimensions of the set consisting of connected components larger than one point and its complement in C (the "dust"). In two dimensions, we also show that the set consisting of connected components larger than one point is a.s. the union of non-trivial H\"older continuous curves, all with the same exponent. Finally, we give a short proof of the fact that in two dimensions, any curve in the limiting set must have Hausdorff dimension strictly larger than 1.Comment: 22 pages, 3 figures, accepted for publication in Journal of Theoretical Probabilit

    xQTL workbench: a scalable web environment for multi-level QTL analysis

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    Summary: xQTL workbench is a scalable web platform for the mapping of quantitative trait loci (QTLs) at multiple levels: for example gene expression (eQTL), protein abundance (pQTL), metabolite abundance (mQTL) and phenotype (phQTL) data. Popular QTL mapping methods for model organism and human populations are accessible via the web user interface. Large calculations scale easily on to multi-core computers, clusters and Cloud. All data involved can be uploaded and queried online: markers, genotypes, microarrays, NGS, LC-MS, GC-MS, NMR, etc. When new data types come available, xQTL workbench is quickly customized using the Molgenis software generator

    Space Use and Movement of Urban Bobcats

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    Global urbanization is rapidly changing the landscape for wildlife species that must learn to persist in declining wild spacing, adapt, or risk extinction. Many mesopredators have successfully exploited urban niches, and research on these species in an urban setting offers insights into the traits that facilitate their success. In this study, we examined space use and activity patterns from GPS-collared bobcats (Lynx rufus) in the Dallas–Fort Worth metroplex, Texas, USA. We found that bobcats select for natural/agricultural features, creeks, and water ways and there is greater home-range overlap in these habitats. They avoid roads and are less likely to have home-range overlap in habitats with more roads. Home-range size is relatively small and overlap relatively high, with older animals showing both greater home-range size and overlap. Simultaneous locations suggest bobcats are neither avoiding nor attracted to one another, despite the high overlap across home ranges. Finally, bobcats are active at all times of day and night. These results suggest that access to natural features and behavioral plasticity may enable bobcats to live in highly developed landscapes

    Arsenic and high affinity phosphate uptake gene distribution in shallow submarine hydrothermal sediments

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    The toxicity of arsenic (As) towards life on Earth is apparent in the dense distribution of genes associated with As detoxification across the tree of life. The ability to defend against As is particularly vital for survival in As-rich shallow submarine hydrothermal ecosystems along the Hellenic Volcanic Arc (HVA), where life is exposed to hydrothermal fluids containing up to 3000 times more As than present in seawater. We propose that the removal of dissolved As and phosphorus (P) by sulfide and Fe(III)(oxyhydr)oxide minerals during sediment-seawater interaction, produces nutrient-deficient porewaters containing < 2.0 ppb P. The porewater arsenite-As(III) to arsenate-As(V) ratios, combined with sulfide concentration in the sediment and/or porewater, suggest a hydrothermally-induced seafloor redox gradient. This gradient overlaps with changing high affinity phosphate uptake gene abundance. High affinity phosphate uptake and As cycling genes are depleted in the sulfide-rich settings, relative to the more oxidizing habitats where mainly Fe(III)(oxyhydr)oxides are precipitated. In addition, a habitat-wide low As-respiring and As-oxidizing gene content relative to As resistance gene richness, suggests that As detoxification is prioritized over metabolic As cycling in the sediments. Collectively, the data point to redox control on Fe and S mineralization as a decisive factor in the regulation of high affinity phosphate uptake and As cycling gene content in shallow submarine hydrothermal ecosystems along the HVA
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