3,861 research outputs found

    The effect of bedrest on various parameters of physiological function. part xii- the effect of bedrest on bone mass and calcium balance

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    Bed rest effect on various parameters of physiological functions - bone mass and calcium balanc

    The spectral-curvature parameter: an alternative tool for the analysis of synchrotron spectra

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    The so-called Spectral Curvature Parameter(SCP), when plotted versus the high-frequency spectral index (alphahighalpha_{high}) of synchrotron sources, provides crucial parameters on the continuum spectrum of synchrotron radiation without the more complex modeling of spectral ageing scenarios. An important merit of the SCP-alphaalpha diagram is the enhanced reliability of extracting multiple injection spectra, alphainjalpha_{inj}. Different from the colour-colour diagram, tracks of different alphainjalpha_{inj}s, especially when the synchrotron particles are young, exhibit less overlap and less smearing in the SCP-alphaalpha diagram. Three giant radio galaxies(GRGs) and a sample of Compact steep spectrum(CSS) souces are presented. GRGs exhibit asymmetries of their injection spectral indices alphainjalpha_{inj} in the SCP-alphahighalpha_{high} diagram. The obtained alphainjalpha_{inj}s and the trends in the sources are cross-checked with the literature and show remarkable confidence. Besides the spectral steepening, spectral flattening is prominent in the radio lobes. The spectral flattening is a clue to efficient re-acceleration processes in the lobes. It implies interaction with the surrounding intergalactic or intra-cluster medium is an important characteristic of GRGs. In the SW lobe of DA240, there is a clear sign of CI and KP/JP bifurcation at the source extremity. This indicates a highly relativistic energy transportation from the core or in situ acceleration in this typical FR I lobe. Our analysis proves, if exists, KP spectra imply the existence of strong BsyncB_{sync} field with Bsync>BCMBB_{sync} > B_{CMB}. In the CSS sources, our result confirms the CI model and Bsync>>BCMBB_{sync} >> B_{CMB}. The synchrotron self-absorption is significant in the CSS sample.Comment: to be published in A&

    Spatial stream modeling of Louisiana Waterthrush (\u3ci\u3eParkesia motacilla\u3c/i\u3e) foraging substrate and aquatic prey in a watershed undergoing shale gas development

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    We demonstrate the use of spatial stream network models (SSNMs) to explore relationships between a semiaquatic bioindicator songbird, Louisiana Waterthrush (Parkesia motacilla), and stream monitoring and benthic macroinvertebrate data in an area undergoing shale gas development. SSNMs allowed us to account for spatial autocorrelation inherent to these environmental data types and stream properties that traditional modeling approaches cannot capture to elucidate factors that affect waterthrush foraging locations. We monitored waterthrush along 58.1 km of 1st- and 2nd-order headwater stream tributaries (n = 14) in northwestern West Virginia over a two year period (2013–2014), sampled benthic macroinvertebrates in waterthrush territories, and collected wetted perimeter stream channel and water chemistry data along a 50 m fixed point stream grid. Spatial models outperformed traditional regression models and made a statistical difference in whether stream covariates of interest were considered relatable to waterthrush foraging. Waterthrush foraging probability index (FPI) was greater in areas where family and genus-level multi-metric indices of biotic stream integrity were higher (i.e. WVSCI and GLIMPSS). Waterthrush were found foraging both among stream flow connected and unconnected sampled sites on relatively further upstream locations where WVSCI and GLIMPSS were predicted to be highest. While there was no significant relationship found between FPI and shale gas land use on a catchment area scale, further information on waterthrush trophic dynamics and bioaccumulation of surface contaminants is needed before establishing the extent to which waterthrush foraging may be affected by shale gas development

    Demographic characteristics of an avian predator, Louisiana Waterthrush (Parkesia motacilla), in response to its aquatic prey in a Central Appalachian USA watershed impacted by shale gas development

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    We related Louisiana Waterthrush (Parkesia motacilla) demographic response and nest sur- vival to benthic macroinvertebrate aquatic prey and to shale gas development parameters using models that accounted for both spatial and non-spatial sources of variability in a Central Appala- chian USA watershed. In 2013, aquatic prey density and pollution intolerant genera (i.e., pollu- tion tolerance value \u3c4) decreased statistically with increased waterthrush territory length but not in 2014 when territory densities were lower. In general, most demographic responses to aquatic prey were variable and negatively related to aquatic prey in 2013 but positively related in 2014. Competing aquatic prey covariate models to explain nest survival were not statistically significant but differed annually and in general reversed from negative to positive influence on daily survival rate. Potential hydraulic fracturing runoff decreased nest survival both years and was statistically significant in 2014. The EPA Rapid Bioassessment protocol (EPA) and Habitat Suitability Index (HSI) designed for assessing suitability requirements for waterthrush were posi- tively linked to aquatic prey where higher scores increased aquatic prey metrics, but EPA was more strongly linked than HSI and varied annually. While potential hydraulic fracturing runoff in 2013 may have increased Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness, in 2014 shale gas territory disturbance decreased EPT richness. In 2014, intolerant genera decreased at the territory and nest level with increased shale gas disturbance suggesting the potential for localized negative effects on waterthrush. Loss of food resources does not seem directly or solely responsible for demographic declines where waterthrush likely were able to meet their foraging needs. However collective evidence suggests there may be a shale gas dis- turbance threshold at which waterthrush respond negatively to aquatic prey community changes. Density-dependent regulation of their ability to adapt to environmental change through acquisition of additional resources may also alter demographic response

    Infrared conductivity of hole accumulation and depletion layers in (Ga,Mn)As- and (Ga,Be)As-based electric field-effect devices

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    We have fabricated electric double-layer field-effect devices to electrostatically dope our active materials, either xx=0.015 Ga1−x_{1-x}Mnx_xAs or xx=3.2×10−4\times10^{-4} Ga1−x_{1-x}Bex_xAs. The devices are tailored for interrogation of electric field induced changes to the frequency dependent conductivity in the accumulation or depletions layers of the active material via infrared (IR) spectroscopy. The spectra of the (Ga,Be)As-based device reveal electric field induced changes to the IR conductivity consistent with an enhancement or reduction of the Drude response in the accumulation and depletion polarities, respectively. The spectroscopic features of this device are all indicative of metallic conduction within the GaAs host valence band (VB). For the (Ga,Mn)As-based device, the spectra show enhancement of the far-IR itinerant carrier response and broad mid-IR resonance upon hole accumulation, with a decrease of these features in the depletion polarity. These later spectral features demonstrate that conduction in ferromagnetic (FM) Ga1−x_{1-x}Mnx_xAs is distinct from genuine metallic behavior due to extended states in the host VB. Furthermore, these data support the notion that a Mn-induced impurity band plays a vital role in the electron dynamics of FM Ga1−x_{1-x}Mnx_xAs. We add, a sum-rule analysis of the spectra of our devices suggests that the Mn or Be doping does not lead to a substantial renormalization of the GaAs host VB

    Application of Multicanonical Multigrid Monte Carlo Method to the Two-Dimensional Ï•4\phi^4-Model: Autocorrelations and Interface Tension

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    We discuss the recently proposed multicanonical multigrid Monte Carlo method and apply it to the scalar Ï•4\phi^4-model on a square lattice. To investigate the performance of the new algorithm at the field-driven first-order phase transitions between the two ordered phases we carefully analyze the autocorrelations of the Monte Carlo process. Compared with standard multicanonical simulations a real-time improvement of about one order of magnitude is established. The interface tension between the two ordered phases is extracted from high-statistics histograms of the magnetization applying histogram reweighting techniques.Comment: 49 pp. Latex incl. 14 figures (Fig.7 not included, sorry) as uuencoded compressed tar fil

    Gravity Dual for Hofman-Strominger Theorem

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    We provide a gravity counterpart of the theorem by Hofman and Strominger that in (1+1) dimension, chiral scale invariance indicates chiral conformal invariance. We show that the strict null energy condition gives a sufficient condition to guarantee the symmetry enhancement. We also investigate a possibility to construct holographic c-function that decreases along the holographic renormalization group flow.Comment: 6 page

    NASA Langley Airborne High Spectral Resolution Lidar Instrument Description

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    NASA Langley Research Center (LaRC) recently developed the LaRC Airborne High Spectral Resolution Lidar (HSRL) to make measurements of aerosol and cloud distribution and optical properties. The Airborne HSRL has undergone as series of test flights and was successfully deployed on the Megacity Initiative: Local and Global Research Observations (MILAGRO) field mission in March 2006 (see Hair et al. in these proceedings). This paper provides an overview of the design of the Airborne HSRL and descriptions of some key subsystems unique to this instrument
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