1,006 research outputs found

    Franchise Taxes of Corporations Having Stock Without Par Value

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    Structural diversity in the type IV pili of multidrug-resistant Acinetobacter

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    Acinetobacter baumannii is a Gram-negative coccobacillus found primarily in hospital settings that has recently emerged as a source of hospital-acquired infections. A. baumannii expresses a variety of virulence factors, including type IV pili, bacterial extracellular appendages often essential for attachment to host cells. Here, we report the high resolution structures of the major pilin subunit, PilA, from three Acinetobacter strains, demonstrating thatA. baumannii subsets produce morphologically distinct type IV pilin glycoproteins. We examine the consequences of this heterogeneity for protein folding and assembly as well as host-cell adhesion by Acinetobacter. Comparisons of genomic and structural data with pilin proteins from other species of soil gammaproteobacteria suggest that these structural differences stem from evolutionary pressure that has resulted in three distinct classes of type IVa pilins, each found in multiple species

    Kinematics of Metal-Poor Stars in the Galaxy. II. Proper Motions for a Large Non-Kinematically Selected Sample

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    We present a revised catalog of 2106 Galactic stars, selected without kinematic bias, and with available radial velocities, distance estimates, and metal abundances in the range 0.0 <= [Fe/H] <= -4.0. This update of the Beers and Sommer-Larsen (1995) catalog includes newly-derived homogeneous photometric distance estimates, revised radial velocities for a number of stars with recently obtained high-resolution spectra, and refined metallicities for stars originally identified in the HK objective-prism survey (which account for nearly half of the catalog) based on a recent re-calibration. A subset of 1258 stars in this catalog have available proper motions, based on measurements obtained with the Hipparcos astrometry satellite, or taken from the updated Astrographic Catalogue (AC 2000; second epoch positions from either the Hubble Space Telescope Guide Star Catalog or the Tycho Catalogue), the Yale/San Juan Southern Proper Motion (SPM) Catalog 2.0, and the Lick Northern Proper Motion (NPM1) Catalog. Our present catalog includes 388 RR Lyrae variables (182 of which are newly added), 38 variables of other types, and 1680 non-variables, with distances in the range 0.1 to 40 kpc.Comment: 31 pages, including 8 figures, to appear in AJ (June 2000), full paper with all figures embedded available at http://pluto.mtk.nao.ac.jp/people/chiba/preprint/halo4

    Rapid Detection of the Varicella Zoster Virus in Saliva

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    Varicella zoster virus (VZV) causes chicken pox on first exposure (usually in children), and reactivates from latency causing shingles (usually in adults). Shingles can be extremely painful, causing nerve damage, organ damage, and blindness in some cases. The virus can be life-threatening in immune-compromised individuals. The virus is very difficult to culture for diagnosis, requiring a week or longer. This invention is a rapid test for VZV from a saliva sample and can be performed in a doctor s office. The kit is small, compact, and lightweight. Detec tion is sensitive, specific, and noninvasive (no needles); only a saliva sample is required. The test provides results in minutes. The entire test is performed in a closed system, with no exposure to infectious materials. The components are made mostly of inexpensive plastic injection molded parts, many of which can be purchased off the shelf and merely assembled. All biological waste is contained for fast, efficient disposal. This innovation was made possible because of discovery of a NASA scientists flight experiment showing the presence of VZV in saliva during high stress periods and disease. This finding enables clinicians to quickly screen patients for VZV and treat the ones that show positive results with antiviral medicines. This promotes a rapid recovery, easing of pain and symptoms, and reduces chances of complications from zoster. Screening of high-risk patients could be incorporated as part of a regular physical exam. These patients include the elderly, pregnant women, and immune-compromised individuals. In these patients, VZV can be a life-threatening disease. In both high- and low-risk patients, early detection and treatment with antiviral drugs can dramatically decrease or even eliminate the clinical manifestation of disease

    Thermospheric poleward wind surge at midlatitudes during great storm intervals

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    We report a significant poleward surge in thermospheric winds at subauroral and midlatitudes following the 17–18 March 2015 great geomagnetic storm. This premidnight surge is preceded by strong westward winds. These disturbances were observed over three sites with geodetic latitudes 35–42°N in the American sector by Fabry-Perot interferometers at 630 nm wavelength. Prior to the wind disturbances, subauroral polarization streams (SAPS) were measured by the Millstone Hill incoherent scatter radar between 20 and 02 UT. We identify the observed neutral wind variations as driven by SAPS, through a scenario where strong ion flows cause a westward neutral wind, subsequently establishing a poleward wind surge due to the poleward Coriolis force on that westward wind. These regional disturbances appear to have prevented the well-known storm time equatorward wind surge from propagating into low latitudes, with the consequence that the classic disturbance dynamo mechanism failed to occur.United States. National Aeronautics and Space Administration (Living with a Star NNX15AB83G
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