2,646 research outputs found

    Information Management System for the California State Water Resources Control Board (SWRCB)

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    A study was made to establish the requirements for an integrated state-wide information management system for water quality control and water quality rights for the State of California. The data sources and end requirements were analyzed for the data collected and used by the numerous agencies, both State and Federal, as well as the nine Regional Boards under the jurisdiction of the State Board. The report details the data interfaces and outlines the system design. A program plan and statement of work for implementation of the project is included

    President Rice Inauguration, 1959, Part 1

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    Inauguration of Macalester College President Harvey Rice, on 10/2/1959. Henry T. Heald, President of the Ford Foundation was the featured speaker. Reel #88, run time 36:0

    Seeking large-scale magnetic fields in a pure-disk dwarf galaxy NGC 2976

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    It is still unknown how magnetic field-generation mechanisms could operate in low-mass dwarf galaxies. Here, we present a detailed study of a nearby pure-disk dwarf galaxy NGC 2976. Unlike previously observed dwarf objects, this galaxy possesses a clearly defined disk. For the purpose of our studies, we performed deep multi-frequency polarimetric observations of NGC 2976 with the VLA and Effelsberg radio telescopes. Additionally, we supplement them with re-imaged data from the WSRT-SINGS survey. The magnetic field morphology discovered in NGC 2976 consists of a southern polarized ridge. This structure does not seem to be due to just a pure large-scale dynamo process (possibly cosmic-ray driven) at work in this object, as indicated by the RM data and dynamo number calculations. Instead, the field of NGC 2976 is modified by past gravitational interactions and possibly also by ram pressure inside the M 81 galaxy group environment. The estimates of total (7 muG) and ordered (3 muG) magnetic field strengths, as well as degree of field order (0.46), which is similar to those observed in spirals, suggest that tidally generated magnetized gas flows can further enhance dynamo action in the object. NGC 2976 is apparently a good candidate for the efficient magnetization of its neighbourhood. It is able to provide an ordered (perhaps also regular) magnetic field into the intergalactic space up to a distance of about 5 kpc. Tidal interactions (and possibly also ram pressure) can lead to the formation of unusual magnetic field morphologies (like polarized ridges) in galaxies out of the star-forming disks, which do not follow any observed component of the interstellar medium (ISM), as observed in NGC 2976. These galaxies are able to provide ordered magnetic fields far out of their main disks.Comment: 16 page

    HI observations of the nearest starburst galaxy NGC 253 with the SKA precursor KAT-7

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    We present HI observations of the Sculptor Group starburst spiral galaxy NGC 253, obtained with the Karoo Array Telescope (KAT-7). KAT-7 is a pathfinder for the SKA precursor MeerKAT, under construction. The short baselines and low system temperature of the telescope make it very sensitive to large scale, low surface brightness emission. The KAT-7 observations detected 33% more flux than previous VLA observations, mainly in the outer parts and in the halo for a total HI mass of 2.1±0.12.1 \pm 0.1 ×109\times 10^{9} M_{\odot}. HI can be found at large distances perpendicular to the plane out to projected distances of ~9-10 kpc away from the nucleus and ~13-14 kpc at the edge of the disk. A novel technique, based on interactive profile fitting, was used to separate the main disk gas from the anomalous (halo) gas. The rotation curve (RC) derived for the HI disk confirms that it is declining in the outer parts, as seen in previous optical Fabry-Perot measurements. As for the anomalous component, its RC has a very shallow gradient in the inner parts and turns over at the same radius as the disk, kinematically lagging by ~100 km/sec. The kinematics of the observed extra planar gas is compatible with an outflow due to the central starburst and galactic fountains in the outer parts. However, the gas kinematics shows no evidence for inflow. Analysis of the near-IR WISE data, shows clearly that the star formation rate (SFR) is compatible with the starburst nature of NGC 253.Comment: 18 pages, 20 figures, 8 Tables. Accepted for publication to MNRA

    Means/Ends Analysis in Copyright Law: Eldred v. Ashcroft in One Act

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    Scene: The quiet hallway of a law school. A troubled young professor of Intellectual Property law stands in front of a senior colleague\u27s office and studies a pencil sketch of Bushrod Washington taped to the door. After a moment\u27s hesitation, he knocks and enters

    Book Reviews

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    Review of the following books: Motor Camps and Maine Guides: Two Studies by Mia Boynton and Nathan Lowrey; A Noble and Dignified Stream: The Piscataqua Region in the Colonial Revival, 1860-1930 edited by Sarah L. Giffen and Kevin D. Murphy; White Pine on the Saco River: An Oral History of River Driving in Southern Maine by Michael P. Chaney

    Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs low-yield pathways

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    Formation of SOA from the aromatic species toluene, xylene, and, for the first time, benzene, is added to a global chemical transport model. A simple mechanism is presented that accounts for competition between low and high-yield pathways of SOA formation, wherein secondary gas-phase products react further with either nitrogen oxide (NO) or hydroperoxy radical (HO2) to yield semi- or non-volatile products, respectively. Aromatic species yield more SOA when they react with OH in regions where the [NO]/[HO2] ratios are lower. The SOA yield thus depends upon the distribution of aromatic emissions, with biomass burning emissions being in areas with lower [NO]/[HO2] ratios, and the reactivity of the aromatic with respect to OH, as a lower initial reactivity allows transport away from industrial source regions, where [NO]/[HO2] ratios are higher, to more remote regions, where this ratio is lower and, hence, the ultimate yield of SOA is higher. As a result, benzene is estimated to be the most important aromatic species with regards to formation of SOA, with a total production nearly equal that of toluene and xylene combined. In total, while only 39% percent of the aromatic species react via the low-NOx pathway, 72% of the aromatic SOA is formed via this mechanism. Predicted SOA concentrations from aromatics in the Eastern United States and Eastern Europe are actually largest during the summer, when the [NO]/[HO2] ratio is lower. Global production of SOA from aromatic sources is estimated at 3.5 Tg/yr, resulting in a global burden of 0.08 Tg, twice as large as previous estimates. The contribution of these largely anthropogenic sources to global SOA is still small relative to biogenic sources, which are estimated to comprise 90% of the global SOA burden, about half of which comes from isoprene. Compared to recent observations, it would appear there are additional pathways beyond those accounted for here for production of anthropogenic SOA. However, owing to differences in spatial distributions of sources and seasons of peak production, there are still regions in which aromatic SOA produced via the mechanisms identified here are predicted to contribute substantially to, and even dominate, the local SOA concentrations, such as outflow regions from North America and South East Asia during the wintertime, though total SOA concentrations there are small (~0.1 μg/m^³)

    A GBT Survey of the HALOGAS Galaxies and Their Environments I: Revealing the full extent of HI around NGC891, NGC925, NGC4414 & NGC4565

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    We present initial results from a deep neutral hydrogen (HI) survey of the HALOGAS galaxy sample, which includes the spiral galaxies NGC891, NGC925, NGC4414, and NGC4565, performed with the Robert C. Byrd Green Bank Telescope (GBT). The resulting observations cover at least four deg2^2 around these galaxies with an average 5σ\sigma detection limit of 1.2×\times1018^{18} cm2^{-2} over a velocity range of 20 km s1^{-1} and angular scale of 9.1'. In addition to detecting the same total flux as the GBT data, the spatial distribution of the GBT and original Westerbork Synthesis Radio Telescope (WSRT) data match well at equal spatial resolutions. The HI mass fraction below HI column densities of 1019^{19} cm2^{-2} is, on average, 2\%. We discuss the possible origins of low column density HI of nearby spiral galaxies. The absence of a considerable amount of newly detected HI by the GBT indicates these galaxies do not have significant extended diffuse HI structures, and suggests future surveys planned with the SKA and its precursors must go \textit{at least} as deep as 1017^{17} cm2^{-2} in column density to significantly increase the probability of detecting HI associated with the cosmic web and/or cold mode accretion.Comment: Accepted for publication in The Astrophysical Journal; 28 pages, 15 figure
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