12,844 research outputs found

    Investigation of heatless desorption technology for carbon dioxide control in manned spacecraft

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    Heatless desorption technology for carbon dioxide control in manned spacecraf

    Unlimited simultaneous discrimination intervals in regression Technical report no. 90

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    Unlimited simultaneous discrimination intervals in linear regression

    Temporal Analysis of Activity Patterns of Editors in Collaborative Mapping Project of OpenStreetMap

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    In the recent years Wikis have become an attractive platform for social studies of the human behaviour. Containing millions records of edits across the globe, collaborative systems such as Wikipedia have allowed researchers to gain a better understanding of editors participation and their activity patterns. However, contributions made to Geo-wikis_wiki-based collaborative mapping projects_ differ from systems such as Wikipedia in a fundamental way due to spatial dimension of the content that limits the contributors to a set of those who posses local knowledge about a specific area and therefore cross-platform studies and comparisons are required to build a comprehensive image of online open collaboration phenomena. In this work, we study the temporal behavioural pattern of OpenStreetMap editors, a successful example of geo-wiki, for two European capital cities. We categorise different type of temporal patterns and report on the historical trend within a period of 7 years of the project age. We also draw a comparison with the previously observed editing activity patterns of Wikipedia.Comment: Submitte

    Testosterone Influence on Gene Expression in Lacrimal Glands of Mouse Models of Sjögren Syndrome

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    Purpose: Sjögren syndrome is an autoimmune disorder that occurs almost exclusively in women and is associated with extensive inflammation in lacrimal tissue, an immune-mediated destruction and/or dysfunction of glandular epithelial cells, and a significant decrease in aqueous tear secretion. We discovered that androgens suppress the inflammation in, and enhance the function of, lacrimal glands in female mouse models (e.g., MRL/MpJ-Tnfrsf6lpr [MRL/lpr]) of Sjögren syndrome. In contrast, others have reported that androgens induce an anomalous immunopathology in lacrimal glands of nonobese diabetic/LtJ (NOD) mice. We tested our hypothesis that these hormone actions reflect unique, strain- and tissue-specific effects, which involve significant changes in the expression of immune-related glandular genes. Methods: Lacrimal glands were obtained from age-matched, adult, female MRL/lpr and NOD mice after treatment with vehicle or testosterone for up to 3 weeks. Tissues were processed for analysis of differentially expressed mRNAs using CodeLink Bioarrays and Affymetrix GeneChips. Data were analyzed with bioinformatics and statistical software. Results: Testosterone significantly influenced the expression of numerous immune-related genes, ontologies, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in lacrimal glands of MRL/lpr and NOD mice. The nature of this hormone-induced immune response was dependent upon the autoimmune strain, and was not duplicated within lacrimal tissues of nonautoimmune BALB/c mice. The majority of immune-response genes regulated by testosterone were of the inflammatory type. Conclusions: Our findings support our hypothesis and indicate a major role for the lacrimal gland microenvironment in mediating androgen effects on immune gene expression

    Energy balance in a low pressure capacitive discharge driven by a double-saddle antenna

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    A radio frequency (rf) plasma is created at low pressure (∼1 mTorr) in the source tube of a “helicon” excited diffusion system in the absence of a dc magnetic field. The coupling is capacitive for the low source power of 160 W at 13.56 MHz considered here. Temperature measurements of the glass source tube yield a plasma power deposition of ∼35 W. The plasma parameters (density, potential, electron temperature) were measured using a retarding field energy analyzer. An analytical model based on the measuredplasma parameters and on additional external parameters measured in the matching box (rf voltages and phase, rf current) is developed. The model takes into account the geometry of the double saddle rf antenna. It is found that the inside of the glass wall adjacent to the antenna wire charges negatively. Ion acceleration into the glass along the antenna and fast electrons escaping the plasma account for most of the power deposition to the walls (∼16.8 W). Secondary electrons liberated by ions impinging onto the glass along the antenna contribute a power of ∼4.6 W. Adding the power of 3.7 W deposited to the part of the tube not affected by the antenna, the total power deposition responsible for the temperature rise of the tube is found to be about 25 W. The model shows that the power deposition is strongly nonuniform along the tube as a result of the antenna geometry. An estimate of the power deposited into the electrons by stochastic heating yields ∼1.4 W, compared to an estimate of 5.8 W for the measured power loss from electrons

    Oseledets' Splitting of Standard-like Maps

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    For the class of differentiable maps of the plane and, in particular, for standard-like maps (McMillan form), a simple relation is shown between the directions of the local invariant manifolds of a generic point and its contribution to the finite-time Lyapunov exponents (FTLE) of the associated orbit. By computing also the point-wise curvature of the manifolds, we produce a comparative study between local Lyapunov exponent, manifold's curvature and splitting angle between stable/unstable manifolds. Interestingly, the analysis of the Chirikov-Taylor standard map suggests that the positive contributions to the FTLE average mostly come from points of the orbit where the structure of the manifolds is locally hyperbolic: where the manifolds are flat and transversal, the one-step exponent is predominantly positive and large; this behaviour is intended in a purely statistical sense, since it exhibits large deviations. Such phenomenon can be understood by analytic arguments which, as a by-product, also suggest an explicit way to point-wise approximate the splitting.Comment: 17 pages, 11 figure

    Jet fuel property changes and their effect on producibility and cost in the U.S., Canada, and Europe

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    The effects of changes in properties and blending stocks on the refinery output and cost of jet fuel in the U.S., Canada, and Europe were determined. Computerized refinery models that minimize production costs and incorporated a 1981 cost structure and supply/demand projections to the year 2010 were used. Except in the West U.S., no changes in jet fuel properties were required to meet all projected demands, even allowing for deteriorating crude qualities and changes in competing product demand. In the West U.S., property changes or the use of cracked blendstocks were projected to be required after 1990 to meet expected demand. Generally, relaxation of aromatics and freezing point, or the use of cracked stocks produced similar results, i.e., jet fuel output could be increased by up to a factor of three or its production cost lowered by up to $10/cu m. High quality hydrocracked stocks are now used on a limited basis to produce jet fuel. The conversion of U.S. and NATO military forces from wide-cut to kerosene-based jet fuel is addressed. This conversion resulted in increased costs of several hundred million dollars annually. These costs can be reduced by relaxing kerosene jet fuel properties, using cracked stocks and/or considering the greater volumetric energy content of kerosene jet fuel

    A planar calculus for infinite index subfactors

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    We develop an analog of Jones' planar calculus for II_1-factor bimodules with arbitrary left and right von Neumann dimension. We generalize to bimodules Burns' results on rotations and extremality for infinite index subfactors. These results are obtained without Jones' basic construction and the resulting Jones projections.Comment: 56 pages, many figure
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