1,880 research outputs found

    Alien Registration- Schneider, Harry (Bangor, Penobscot County)

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    https://digitalmaine.com/alien_docs/10831/thumbnail.jp

    First Ultraviolet Spectrum of a Brown Dwarf: Evidence for H_2 Fluorescence and Accretion

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    We analyze an HST/STIS ultraviolet spectrum of the young brown dwarf 2MASSW J1207334-393254, a member of the ten million-year old TW Hya Association that has a planetary-mass companion. We detect and identify numerous emission lines. CIV and other ions are seen that arise in hot gas. We identify a series of lines with Lyman-pumped H_2 molecular lines, indicating that cool gas is also present. Overall, this substellar object shows many of the same characteristics as classical T Tauri stars. We interpret our results as direct evidence of accretion from a circumstellar gas disk, consistent with previous claims. The lack of SiIV emission from the accreting gas indicates that silicon has been depleted into grains.Comment: 8 pages, to appear in Astrophysical Journal Letter

    Multi-site Calibration and Validation of a Net Ecosystem Carbon Exchange Model for Croplands

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    Croplands play an important role in the carbon budget of many regions. However, the estimation of their carbon balance remains difficult due to diversity and complexity of the processes involved. We report the coupling of a one-dimensional soil water, heat, and CO2 flux model (SOILCO2), a pool concept of soil carbon turnover (RothC), and a crop growth module (SUCROS) to predict the net ecosystem exchange (NEE) of carbon. The coupled model, further referred to as AgroC, was extended with routines for managed grassland as well as for root exudation and root decay. In a first step, the coupled model was applied to two winter wheat sites and one upland grassland site in Germany. The model was calibrated based on soil water content, soil temperature, biometric, and soil respiration measurements for each site, and validated in terms of hourly NEE measured with the eddy covariance technique. The overall model performance of AgroC was sufficient with a model efficiency above 0.78 and a correlation coefficient above 0.91 for NEE. In a second step, AgroC was optimized with eddy covariance NEE measurements to examine the effect of different objective functions, constraints, and data-transformations on estimated NEE. It was found that NEE showed a distinct sensitivity to the choice of objective function and the inclusion of soil respiration data in the optimization process. In particular, both positive and negative day‑ and nighttime fluxes were found to be sensitive to the selected optimization strategy. Additional consideration of soil respiration measurements improved the simulation of small positive fluxes remarkably. Even though the model performance of the selected optimization strategies did not diverge substantially, the resulting cumulative NEE over simulation time period differed substantially. Therefore, it is concluded that data-transformations, definitions of objective functions, and data sources have to be considered cautiously when a terrestrial ecosystem model is used to determine NEE by means of eddy covariance measurements

    Metabolically exaggerated cardiac reactions to acute psychological stress: The effects of resting blood pressure status and possible underlying mechanisms

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    The study aimed to: confirm that acute stress elicits metabolically exaggerated increases in cardiac activity; test whether individuals with elevated resting blood pressure show more exaggerated cardiac reactions to stress than those who are clearly normotensive; and explore the underlying mechanisms. Cardiovascular activity and oxygen consumption were measured pre-, during, and post- mental stress, and during graded submaximal cycling exercise in 11 young men with moderately elevated resting blood pressure and 11 normotensives. Stress provoked increases in cardiac output that were much greater than would be expected from contemporary levels of oxygen consumption. Exaggerated cardiac reactions were larger in the relatively elevated blood pressure group. They also had greater reductions in total peripheral resistance, but not heart rate variability, implying that their more exaggerated cardiac reactions reflected greater β-adrenergic activation

    Different doses of supplemental vitamin D maintain interleukin-5 without altering skeletal muscle strength: a randomized, double-blind, placebo-controlled study in vitamin D sufficient adults

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    <p>Abstract</p> <p>Background</p> <p>Supplemental vitamin D modulates inflammatory cytokines and skeletal muscle function, but results are inconsistent. It is unknown if these inconsistencies are dependent on the supplemental dose of vitamin D. Therefore, the purpose of this study was to identify the influence of different doses of supplemental vitamin D on inflammatory cytokines and muscular strength in young adults.</p> <p>Methods</p> <p>Men (<it>n </it>= 15) and women (<it>n </it>= 15) received a daily placebo or vitamin D supplement (200 or 4000 IU) for 28-d during the winter. Serum 25-hydroxyvitamin D (25(OH)D), cytokine concentrations and muscular (leg) strength measurements were performed prior to and during supplementation. Statistical significance of data were assessed with a two-way (time, treatment) analysis of variance (ANOVA) with repeated measures, followed by a Tukey's Honestly Significant Difference to test multiple pairwise comparisons.</p> <p>Results</p> <p>Upon enrollment, 63% of the subjects were vitamin D sufficient (serum 25(OH)D ≥ 30 ng/ml). Serum 25(OH)D and interleukin (IL)-5 decreased (<it>P </it>< 0.05) across time in the placebo group. Supplemental vitamin D at 200 IU maintained serum 25(OH)D concentrations and increased IL-5 (<it>P </it>< 0.05). Supplemental vitamin D at 4000 IU increased (<it>P </it>< 0.05) serum 25(OH)D without altering IL-5 concentrations. Although serum 25(OH)D concentrations correlated (<it>P </it>< 0.05) with muscle strength, muscle strength was not changed by supplemental vitamin D.</p> <p>Conclusion</p> <p>In young adults who were vitamin D sufficient prior to supplementation, we conclude that a low-daily dose of supplemental vitamin D prevents serum 25(OH)D and IL-5 concentration decreases, and that muscular strength does not parallel the 25(OH)D increase induced by a high-daily dose of supplemental vitamin D. Considering that IL-5 protects against viruses and bacterial infections, these findings could have a broad physiological importance regarding the ability of vitamin D sufficiency to mediate the immune systems protection against infection.</p

    The β3-integrin endothelial adhesome regulates microtubule-dependent cell migration

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    Integrin β3 is seen as a key anti-angiogenic target for cancer treatment due to its expression on neovasculature, but the role it plays in the process is complex; whether it is pro- or anti-angiogenic depends on the context in which it is expressed. To understand precisely β3's role in regulating integrin adhesion complexes in endothelial cells, we characterised, by mass spectrometry, the β3-dependent adhesome. We show that depletion of β3-integrin in this cell type leads to changes in microtubule behaviour that control cell migration. β3-integrin regulates microtubule stability in endothelial cells through Rcc2/Anxa2-driven control of active Rac1 localisation. Our findings reveal that angiogenic processes, both in vitro and in vivo, are more sensitive to microtubule targeting agents when β3-integrin levels are reduced
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