18,922 research outputs found

    TOPEX orbital radiation study

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    The space radiation environment of the TOPEX spacecraft is investigated. A single trajectory was considered. The external (surface incident) charged particle radiation, predicted for the satellite, is determined by orbital flux integration for the specified trajectory. The latest standard models of the environment are used in the calculations. The evaluation is performed for solar maximum conditions. The spacecraft exposure to cosmic rays of galactic origin is evaluated over its flight path through the magnetosphere in terms of geomagnetic shielding effects, both for surface incident heavy ions and for particles emerging behind different material thickness. Limited shielding and dose evaluations are performed for simple infinite slab and spherical geometries. Results, given in graphical and tabular form, are analyzed, explained, and discussed. Conclusions are presented and commented on

    Intermediate-mass Black Holes in Galactic Nuclei

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    We present the first homogeneous sample of intermediate-mass black hole candidates in active galactic nuclei. Starting with broad-line active nuclei from the Sloan Digital Sky Survey, we use the linewidth-luminosity-mass scaling relation to select a sample of 19 galaxies in the mass range M_BH ~ 8 x 10^4 - 10^6 solar masses. In contrast to the local active galaxy population, the host galaxies are ~1 mag fainter than M* and thus are probably late-type systems. The active nuclei are also faint, with M_g ~ -15 to -18 mag, while the bolometric luminosities are close to the Eddington limit. The spectral properties of the sample are compared to the related class of objects known as narrow-line Seyfert 1 galaxies. We discuss the importance of our sample as observational analogues of primordial black holes, contributors to the integrated signal for future gravitational wave experiments, and as a valuable tool in the calibration of the M-sigma relation.Comment: 4 pages, 4 figures. To appear in "The Interplay among Black Holes, Stars and ISM in Galactic Nuclei," Proc. IAU 222 (Gramado, Brazil), eds Th. Storchi Bergmann, L.C. Ho, H.R. Schmit

    Accounting for Food Preserving Companies

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    Astronomy for Educators

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    Astronomy for Educators provides new and accomplished K-12 instructors with concepts and projects for low-cost, high-impact STEM classroom instruction that is built around the National Academies National Research Council\u27s K-12 Framework for Science Education.https://scholarworks.uark.edu/oer/1001/thumbnail.jp

    SOFIP: A Short Orbital Flux Integration Program

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    A computer code was developed to evaluate the space radiation environment encountered by geocentric satellites. The Short Orbital Flux Integration Program (SOFIP) is a compact routine of modular compositions, designed mostly with structured programming techniques in order to provide core and time economy and ease of use. The program in its simplest form produces for a given input trajectory a composite integral orbital spectrum of either protons or electrons. Additional features are available separately or in combination with the inclusion of the corresponding (optional) modules. The code is described in detail, and the function and usage of the various modules are explained. A program listing and sample outputs are attached

    A Case of Autoimmune Hepatitis Treated with Rituximab

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    Autoimmune hepatitis (AIH) is a form of chronic hepatitis of unknown etiology. It was first described in the 1950s as a form of chronic hepatitis noted in younger women. It was later termed lupoid hepatitis due to its association with autoantibodies before being named AIH in 1965. Corticosteroids and azathioprine have been the standard therapy for AIH, but due to treatment failures and toxicities from these medications, new medications are being investigated as possible treatment options. Rituximab has been used in various autoimmune disorders with good success. We report the case of a 34-year-old Caucasian woman with a history of B cell lymphoma and concurrent AIH treated with rituximab. The diagnosis of AIH was made by classic serological and histological features. The patient was initially treated with steroids but had a progression of her disease as well as suffering toxicities from the steroids. She was then given eight weeks of rituximab with good improvement in both laboratory and histological findings

    Cost analysis of advanced turbine blade manufacturing processes

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    A rigorous analysis was conducted to estimate relative manufacturing costs for high technology gas turbine blades prepared by three candidate materials process systems. The manufacturing costs for the same turbine blade configuration of directionally solidified eutectic alloy, an oxide dispersion strengthened superalloy, and a fiber reinforced superalloy were compared on a relative basis to the costs of the same blade currently in production utilizing the directional solidification process. An analytical process cost model was developed to quantitatively perform the cost comparisons. The impact of individual process yield factors on costs was also assessed as well as effects of process parameters, raw materials, labor rates and consumable items

    Usefulness of fair valuation of biological assets for cash flow prediction

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    This study develops an empirical analysis of the relevance of accounting information when biological assets are measured at fair value. We use an international sample of firms with biological assets.We find that biological assets influence unpredictability when they are measured at historical cost (HC). In this case, the ability of accounting data to predict future cash flows diminishes as the proportion of biological assets on total assets increases. The valuation at fair value (FV) switches this negative influence of biological assets to a positive one. We find that when they are measured at FV, the prediction accuracy of future cash flows improves as the ratio of biological assets to total assets increases. This evidence is robust to differentmeasures of prediction accuracy, as well as to the improvement of accounting standards, regardless of FV, over time. The evidence is weaker for bearer plants
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