381 research outputs found

    Antimicrobial resistance among important bovine pathogens isolated at the KSU Veterinary Diagnostic Laboratory over two and a half years

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    A retrospective study was conducted to determine the prevalence of antimicrobial resistance among six important bacterial pathogens of bovine origin. The study extended from June 1990 through December 1992 and included a review of the microbiology records of bovine submissions to the KSU Veterinary Diagnostic Laboratory. Antimicrobial susceptibility results for Pasteurella haemolytica, Pasteurella multocida, Actinomyces pyogenes, Hemophilus somnus, Escherichia coli, and Salmonella spp. are summarized. Pathogens were recovered primarily from cases of pneumonia and/or diarrhea. Each isolate was tested for susceptibility to 14 different antimicrobial agents. A high prevalence of resistance (>70%) was noticed for respiratory pathogens to sulfachloropyridazine. In addition, Pasteurella spp. were very resistant (>71%) to sulfadimethoxine. Most of the H. somnus isolates showed little resistance (<35%) to 12 of the 14 drugs tested. A. pyogenes isolates were generally susceptible to most antimicrobials except sulfa drugs. As expected, a high prevalence of resistance (>70%) was noticed for enteric pathogens (Salmonella and E. coli) to most of the antimicrobials tested

    Procedure for the assessment of the conglomerate resources of the Sherwood Sandstone Group

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    Field and laboratory studies to investigate the regional assessment of the conglomerate resources of the Sherwood Sandstone Group (formerly the Bunter Pebble Beds) are described and illustrated. They have included trials of air-flush hammer drilling, the evaluation of the grain-size distribution of comminuted bulk samples taken from boreholes against natural samples and down-the-hole photography. Limiting arbitrary physical criteria are proposed. The integration and presentation of geological and assessment data by means of a resource map and report are outlined

    Reflection and Ducting of Gravity Waves Inside the Sun

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    Internal gravity waves excited by overshoot at the bottom of the convection zone can be influenced by rotation and by the strong toroidal magnetic field that is likely to be present in the solar tachocline. Using a simple Cartesian model, we show how waves with a vertical component of propagation can be reflected when traveling through a layer containing a horizontal magnetic field with a strength that varies with depth. This interaction can prevent a portion of the downward-traveling wave energy flux from reaching the deep solar interior. If a highly reflecting magnetized layer is located some distance below the convection zone base, a duct or wave guide can be set up, wherein vertical propagation is restricted by successive reflections at the upper and lower boundaries. The presence of both upward- and downward-traveling disturbances inside the duct leads to the existence of a set of horizontally propagating modes that have significantly enhanced amplitudes. We point out that the helical structure of these waves makes them capable of generating an alpha-effect, and briefly consider the possibility that propagation in a shear of sufficient strength could lead to instability, the result of wave growth due to over-reflection.Comment: 23 pages, 5 figures. Accepted for publication in Solar Physic

    Sea surface mixed layer during the 10-11 June 1994 California coastally trapped event

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    A midlevel, coastally trapped atmospheric event occurred along the California coast 10-11 June 1994. This feature reversed the surface wind field along the coast in a northerly phase progression. Along the central California coast, the winds at the coastal stations reverse before the corresponding coastal buoy offshore, then followed hours later by passage of the leading edge of an overcast stratus cloud. The sea surface temperature was much colder in the narrow strip along the coast. The cloud characteristics may be accounted for by a sea surface mixed layer (SSML) model beginning with the wind reversal and growing with the square root of time. Heat is lost from the SSML to the sea surface. A cloud forms when the air temperature at the top of the SSML is equal to the dewpoint. It is suggested that a bore develops on the top of the SSML, increasing the thickness of the SSML and the progression speed of the cloud to 8 m s-1. There is evidence that an undular bore with a leading cloud develops in the thinner inshore SSML. Advancing beyond Monterey Bay, horizontal density contrast is believed to have caused the bore to change character to a gravity current with a narrower cloud that passed a point inshore before the winds reversed at the buoys. The last trace of a disturbed boundary layer ended at Point Arena where strong northerly winds prevented any further northerly progression and contributed to a cyclonic eddy that was formed in the lee of the point. Caution is suggested in the interpretation of stratus cloud phase progression without coastal wind measurements

    Geophysical surveys to help map buried igneous intrusions, Snowdonia, North Wales, UK

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    The geology of the Snowdonia National Park in North Wales comprises a mixture of Lower Palaeozoic shallow marine sediments, acidic igneous rocks and basic intrusions of the Welsh Basin that were subsequently deformed during the Caledonian Orogeny. Thin igneous intrusions are challenging to map due to variable surface exposures, their intrusive origin, structural deformation and burial by glacial sediments. This study used a combination of traditional geological techniques, near-surface geophysical surveys and remote sensing to detect and map a buried dolerite sheet intrusion. Both simple and mathematical analysis of magnetic anomalies and numerical modelling allowed the dolerite position, depths and target widths to be determined. Results showed that calibrated magnetic surveys can characterize buried igneous bodies in such mountainous environments

    Theoretical study of incoherent phi photoproduction on a deuteron target

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    We study the photoproduction of phi mesons in deuteron, paying attention to the modification of the cross section from bound protons to the free ones with the aim of comparing with recent results at LEPS. For this purpose we take into account Fermi motion in single scattering and rescattering of the phi to account for phi absorption on a second nucleon as well as the rescattering of the proton. We find that the contribution of the double scattering is much smaller than the typical cross section of gamma p to phi p in free space, which implies a very small screening of the phi production in deuteron. The contribution from the proton rescattering, on the other hand, is found to be not negligible compared to the cross section of gamma p to phi p in free space, and leads to a moderate reduction of the phi photoproduction cross section on a deuteron at forward angles if LEPS set up is taken into account. The Fermi motion allows contribution of the single scattering in regions forbidden by phase space in the free case. In particular, we find that for momentum transferred squared close to the maximum value, the Fermi motion changes drastically the shape of d sigma / dt, to the point that the ratio of this cross section to the free one becomes very sensitive to the precise value of t chosen, or the size of the bin used in an experimental analysis. Hence, this particular region of t does not seem the most indicated to find effects of a possible phi absorption in the deuteron. This reaction is studied theoretically as a function of t and the effect of the experimental angular cuts at LEPS is also discussed, providing guidelines for future experimental analyses of the reaction.Comment: 17 pages, 16 figure

    Memory Th1 Cells Are Protective in Invasive Staphylococcus aureus Infection

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    Mechanisms of protective immunity to Staphylococcus aureus infection in humans remain elusive. While the importance of cellular immunity has been shown in mice, T cell responses in humans have not been characterised. Using a murine model of recurrent S. aureus peritonitis, we demonstrated that prior exposure to S. aureus enhanced IFNÎł responses upon subsequent infection, while adoptive transfer of S. aureus antigen-specific Th1 cells was protective in naĂŻve mice. Translating these findings, we found that S. aureus antigen-specific Th1 cells were also significantly expanded during human S. aureus bloodstream infection (BSI). These Th1 cells were CD45RO+, indicative of a memory phenotype. Thus, exposure to S. aureus induces memory Th1 cells in mice and humans, identifying Th1 cells as potential S. aureus vaccine targets. Consequently, we developed a model vaccine comprising staphylococcal clumping factor A, which we demonstrate to be an effective human T cell antigen, combined with the Th1-driving adjuvant CpG. This novel Th1-inducing vaccine conferred significant protection during S. aureus infection in mice. This study notably advances our understanding of S. aureus cellular immunity, and demonstrates for the first time that a correlate of S. aureus protective immunity identified in mice may be relevant in humans
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