562 research outputs found

    What Constitutes Doing Business in Virginia

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    Management characteristics of beef cattle production in the Northern Plains and Midwest regions of the United States

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    A comprehensive life cycle assessment of United States beef will provide benchmarks and identify opportunities for improvement. On-going region-specific data collection is characterizing cattle production practices for a more accurate assessment. This study reports production information obtained via online surveys and on-site visits from 2 of 7 regions: the Northern Plains (Nebraska, North Dakota, and South Dakota) and Midwest (Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, and Wisconsin). Ranch responses (n = 512) represented 1.6% of beef cows maintained in both regions with operation sizes varying from 1 to 12,500 cows. Feedlot responses (n = 120) represented 9.6 and 3.7% of cattle finished in the Northern Plains and Midwest, respectively. Ranch herd sizes increased and stocking rates decreased moving westward. Average animal BW increased from south to north. Also recorded were bull and replacement heifer numbers; housing facilities; feed production and use; and machinery, energy, and labor use. Feedlot characteristics including entering and final BW, background and finish feeding periods, crop area per animal, and labor were similar across the regions, but the Northern Plains reported larger feedlots than the Midwest. Diets were similar across regions except that slightly more distillers grain and less corn were fed in the Northern Plains. Ninety-three percent of feedlots produced most of their feed (corn grain, corn silage, and alfalfa). Cropland producing feed received most of the manure produced, but a few large feedlots reported composting and export. Information gathered provides production system characteristics and inventory for conducting a comprehensive United States beef life cycle assessment

    Annual Cycle of Cloud Forcing of Surface Radiation Budget

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    The climate of the Earth is determined by its balance of radiation. The incoming and outgoing radiation fluxes are strongly modulated by clouds, which are not well understood. The Earth Radiation Budget Experiment (Barkstrom and Smith, 1986) provided data from which the effects of clouds on radiation at the top of the atmosphere (TOA) could be computed (Ramanathan, 1987). At TOA, clouds increase the reflected solar radiation, tending to cool the planet, and decrease the OLR, causing the planet to retain its heat (Ramanathan et al., 1989; Harrison et al., 1990). The effects of clouds on radiation fluxes are denoted cloud forcing. These shortwave and longwave forcings counter each other to various degrees, so that in the tropics the result is a near balance. Over mid and polar latitude oceans, cloud forcing at TOA results in large net loss of radiation. Here, there are large areas of stratus clouds and cloud systems associated with storms. These systems are sensitive to surface temperatures and vary strongly with the annual cycle. During winter, anticyclones form over the continents and move to the oceans during summer. This movement of major cloud systems causes large changes of surface radiation, which in turn drives the surface temperature and sensible and latent heat released to the atmosphere

    Modelling the direct effect of aerosols in the solar near-infrared on a planetary scale

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    International audienceWe used a spectral radiative transfer model to compute the direct radiative effect (DRE) of natural plus anthropogenic aerosols in the solar near-infrared (IR), between 0.85?10 ?m, namely, their effect on the outgoing near-IR radiation at the top of atmosphere (TOA, ?FTOA), on the atmospheric absorption of near-IR radiation (?Fatmab) and on the surface downward and absorbed near-IR radiation (?Fsurf, and ?Fsurfnet, respectively). The computations were performed on a global scale (over land and ocean) under all-sky conditions, using detailed spectral aerosol optical properties taken from the Global Aerosol Data Set (GADS) supplemented by realistic data for the rest of surface and atmospheric parameters. The computed aerosol DRE, averaged over the 12-year period 1984?1995 for January and July, shows that on a global mean basis aerosols produce a planetary cooling by increasing the scattered near-IR radiation back to space by 0.48 W m?2, they warm the atmosphere by 0.37 W m?2 and cool the surface by decreasing the downward and absorbed near-IR radiation at surface by 1.03 and 0.85 W m?2, respectively. The magnitude of the near-IR aerosol DRE is smaller than that of the combined ultraviolet (UV) and visible DRE, but it is still energetically important, since it contributes to the total shortwave (SW) DRE by 22?31%. The aerosol-produced near-IR surface cooling combined with the atmospheric warming, may affect the thermal dynamics of the Earth-atmosphere system, by increasing the atmospheric stability, decreasing thus cloud formation, and precipitation, especially over desertification threatened regions such as the Mediterranean basin. This, together with the fact that the sign of near-IR aerosol DRE is sometimes opposite to that of UV-visible DRE, demonstrates the importance of performing detailed spectral computations to provide estimates of the climatic role of aerosols for the Earth-atmosphere system. This was demonstrated by sensitivity tests revealing very large differences (up to 300%) between aerosol DREs computed using detailed spectral and spectrally-averaged aerosol optical properties. Our model results indicate thus that the aerosol direct radiative effect on the near-IR radiation is very sensitive to the treatment of the spectral dependence of aerosol optical properties and solar radiation

    Evaluating Surface Flux Results from CERES-FLASHFlux

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    The Fast Longwave and Shortwave Radiative Flux (FLASHFlux) data product was developed to provide a rapid release version of the Clouds and Earth's Radiant Energy System (CERES) results, which could be made available to the research and applications communities within one week of the satellite observations by exchanging some accuracy for speed of processing. Unlike standard CERES products, FLASHFlux does not maintain a long-term consistent record. Therefore the latest algorithm changes and input data can be incorporated into processing. FLASHFlux released Version3A (January 2013) and Version 3B (August 2014) which include the latest meteorological product from Global Modeling and Assimilation Office (GMAO), GEOS FP-IT (5.9.1), the latest spectral response functions and gains for the CERES instruments, and aerosol climatology based on the latest MATCH data. Version 3B included a slightly updated calibration and some changes to the surface albedo over snow/ice. Typically FLASHFlux does not reprocess earlier versions when a new version is released. The combined record of Time Interpolated Space Averaged (TISA) surface flux results from Versions3A and 3B for July 2012 to October 2015 have been compared to the ground-based measurements. The FLASHFlux results are also compared to two other CERES gridded products, SYN1deg and EBAF surface fluxes

    The direct effect of aerosols on solar radiation based on satellite observations, reanalysis datasets, and spectral aerosol optical properties from Global Aerosol Data Set (GADS)

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    International audienceA global estimate of the seasonal direct radiative effect (DRE) of natural plus anthropogenic aerosols on solar radiation under all-sky conditions is obtained by combining satellite measurements and reanalysis data with a spectral radiative transfer model and spectral aerosol optical properties taken from the Global Aerosol Data Set (GADS). The estimates are obtained with detailed spectral model computations separating the ultraviolet (UV), visible and near-infrared wavelengths. The global distribution of spectral aerosol optical properties was taken from GADS whereas data for clouds, water vapour, ozone, carbon dioxide, methane and surface albedo were taken from various satellite and reanalysis datasets. Using these aerosol properties and other related variables, we generate climatological (for the 12-year period 1984?1995) monthly mean aerosol DREs. The global annual mean DRE on the outgoing SW radiation at the top of atmosphere (TOA, ?FTOA) is ?1.62 W m?2 (with a range of ?15 to 10 W m?2, negative values corresponding to planetary cooling), the effect on the atmospheric absorption of SW radiation (?Fatmab) is 1.6 W m?2 (values up to 35 W m?2, corresponding to atmospheric warming), and the effect on the surface downward and absorbed SW radiation (?Fsurf, and ?Fsurfnet, respectively) is ?3.93 and ?3.22 W m?2 (values up to ?45 and ?35 W m?2, respectively, corresponding to surface cooling). According to our results, aerosols decrease/increase the planetary albedo by ?3 to 13% at the local scale, whereas on planetary scale the result is an increase of 1.5%. Aerosols can warm locally the atmosphere by up to 0.98 K day?1, whereas they can cool the Earth's surface by up to ?2.9 K day?1. Both these effects, which can significantly modify atmospheric dynamics and the hydrological cycle, can produce significant planetary cooling on a regional scale, although planetary warming can arise over highly reflecting surfaces. The aerosol DRE at the Earth's surface compared to TOA can be up to 15 times larger at the local scale. The largest aerosol DRE takes place in the northern hemisphere both at the surface and the atmosphere, arising mainly at ultraviolet and visible wavelengths

    Modelling the direct effect of aerosols in the solar near-infrared on a planetary scale

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    International audienceWe used a spectral radiative transfer model to compute the direct radiative effect (DRE) of natural plus anthropogenic aerosols in the solar near-infrared (IR), between 0.85?10 µm, namely, their effect on the outgoing near-IR radiation at the top of atmosphere (TOA, ?FTOA), on the atmospheric absorption of near-IR radiation (?Fatmab) and on the surface downward and absorbed near-IR radiation (?Fsurf, and ?Fsurfnet, respectively). The computations were performed on a global scale (over land and ocean) under all-sky conditions, using spectral aerosol optical properties taken from the Global Aerosol Data Set (GADS) supplemented by realistic data for the rest of surface and atmospheric parameters. The computed aerosol DRE, averaged over the 12-year period 1984?1995 for January and July, shows that aerosols produce a planetary cooling by increasing the scattered near-IR radiation back to space (by up to 6 Wm?2), they warm the atmosphere (by up to 7 Wm?2) and cool the surface (by up to 12 Wm?2). However, they can also slightly warm the Earth-atmosphere system or cool the atmosphere (by less than 1 Wm?2) over limited areas. The magnitude of the near-IR aerosol DRE is smaller than that of the combined ultraviolet (UV) and visible DRE, but it is still energetically important, since it contributes to the total shortwave (SW) DRE by 22?31%. On a global mean basis, the DREs ?FTOA, ?Fatmab, ?Fsurf, and ?Fsurfnet are equal to about 0.48, 0.37, ?1.03 and ?0.85 Wm?2, i.e. their magnitude is similar to that of climate forcing associated with increasing concentrations of greenhouse gases. The aerosol induced near-IR surface cooling combined with the atmospheric warming, affects the thermal dynamics of the Earth-atmosphere system, by increasing the atmospheric stability, decreasing thus cloud formation, and precipitation, especially over desertification threatened regions such as the Mediterranean basin. This, together with the fact that the sign of near-IR aerosol DRE is sometimes opposite to that of UV-visible DRE, demonstrates the importance of performing detailed spectral computations to provide estimates of the climatic role of aerosols for the Earth-atmosphere system

    Ion association in lanthanide chloride solutions

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    A better understanding of the solution chemistry of the lanthanide (Ln) salts in water would have wide ranging implications in materials processing, waste management, element tracing, medicine and minerals processing ‐ particularly given governmental concerns about Ln security of supply. Despite much effort, even in simple systems, the mechanisms and thermodynamics of Ln(III) association with small anions remain unclear. In the present study, molecular dynamics (MD), using a newly developed force field, provide new insights into LnCl₃(aq) solutions. (Adaptive) bias MD simulations show that the mechanisms for ion pairing change from dissociative to associative exchange depending upon cation size. Thermodynamics of association reveal that while ion pairing is favorable, the equilibrium distribution of species at low concentration is dominated by weakly bound solvent shared and solvent separated ion pairs cf. contact ion pairs, reconciling a number of contrasting observations of Ln(III)‐‐Cl association in the literature. In addition, we show that the thermodynamic stabilities of a range of inner sphere and outer sphere LnClχ coordination complexes are comparable and that the kinetics of anion binding to cations may control solution speciation distributions beyond ion pairs. The techniques adopted in this work provide a framework with which to investigate more complex solution chemistries of cations in water

    Rapid, low-input, low-bias construction of shotgun fragment libraries by high-density in vitro transposition

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    © The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Genome Biology 11 (2010): R119, doi:10.1186/gb-2010-11-12-r119.We characterize and extend a highly efficient method for constructing shotgun fragment libraries in which transposase catalyzes in vitro DNA fragmentation and adaptor incorporation simultaneously. We apply this method to sequencing a human genome and find that coverage biases are comparable to those of conventional protocols. We also extend its capabilities by developing protocols for sub-nanogram library construction, exome capture from 50 ng of input DNA, PCR-free and colony PCR library construction, and 96-plex sample indexing.This work was supported in part by grants from the National Institutes of Health/National Heart Lung and Blood Institute (R01 HL094976 to JS), the National Institutes of Health/National Human Genome Research Institute (R21 HG004749 to JS), the National Institutes of Health/National Institute of Allergy and Infectious Disease Northwest Regional Center of Excellence for Biodefense and Emerging Infectious Diseases at the University of Washington (3U54AI05714), the Ministry of Science and Technology of China, 863 program (2006AA02A301), and an NSF Graduate Research Fellowship (to JOK)
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