802 research outputs found

    First results of the OROMA experiment in the Lister Tief of the German Bight in the North Sea, EARSeL Proceedings

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    The objective of the project entitled “Operational Radar and Optical Mapping in monitoring hydrodynamic, morphodynamic and environmental parameters for coastal management (OROMA)” within the Fifth Framework Programme of the European Commission (EC) is to improve the effectiveness of monitoring technologies in coastal waters. The Research Vessel (R.V.) Ludwig Prandtl of the GKSS research centre was equipped with special sensors and instruments to measure the position of the ship, the water depth, the salinity, the water temperature, the current speed and direction, the modulation characteristics of short-wave energies, and relevant air-sea interaction parameters due to the presence of submarine sand waves. The first experiment of the OROMA project on 5-16 August 2002 took place in the Lister Tief, a tidal inlet of the German Bight in the North Sea. The seabed morphology of the Lister Tief reveals a complex configuration of different bedforms which is four-dimensional in space and time. A significant upward orientated component uvert of the three-dimensional current velocity field was observed. Marked vertically so-called waterspouts of uvert above the crests of sand waves have been measured by the Acoustic Doppler Current Profiler (ADCP) as straight lines. They cause water upwelling with turbulence patterns at the water surface affecting the Normalized Radar Cross Section (NRCS) modulation. A first impression of expected NRCS modulation signatures of sea bottom topography detected by the GKSS shipborne X-band radar are presented as an uncalibrated composite of five single sea clutter images acquired in the Lister Tief on 22 November 1990

    Breakdown of accommodation in nerve: a possible role for persistent sodium current

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    BACKGROUND: Accommodation and breakdown of accommodation are important elements of information processing in nerve fibers, as they determine how nerve fibers react to natural slowly changing stimuli or electrical stimulation. The aim of the present study was to elucidate the biophysical mechanism of breakdown of accommodation, which at present is unknown. RESULTS: A model of a space-clamped motor nerve fiber was developed. It was found that this new model could reproduce breakdown of accommodation when it included a low-threshold, rapidly activating, persistent sodium current. However, the phenomenon was not reproduced when the persistent sodium current did not have fast activation kinetics or a low activation threshold. CONCLUSION: The present modeling study suggests that persistent, low-threshold, rapidly activating sodium currents have a key role in breakdown of accommodation, and that breakdown of accommodation can be used as a tool for studying persistent sodium current under normal and pathological conditions

    The Origin of Xenoliths with Cumulus Textures Found Above the Subsurface Extension of the Stillwater Complex, Montana

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    The Archean Stillwater Complex is a large layered mafic-ultramafic intrusion (LMI) exposed in the Beartooth Mountains of south-central Montana. Gravity measurements suggest that the north-dipping complex extends under cover at depth. Some of the exposures located above the subsurface Stillwater Complex are younger Cretaceous stocks (Susie Peak and Sliderock Mountain stocks), diorite sills and andesite dikes, exposed north of the complex, passed through area of the gravity anomaly that may be the Stillwater Complex. In the summer of 2013, samples of the stocks and their included xenoliths (foreign rock fragments; commonly metamorphosed to greenschist facies conditions) were collected for study. Xenoliths with textures reminiscent of Stillwater Complex cumulates were chosen for further investigation. The host andesitic rocks containing the xenoliths exhibit porphyritic textures—phenocrysts of plagioclase, amphibole ± biotite occur in a finer-grained groundmass of the same minerals. Electron microprobe analyses of amphibole grains from both the host and xenolith are comparable in composition. Electron microprobe analyses for two samples of coexisting xenolith amphibole (Tschermakitic hornblende, magnesio-hastingsite) and plagioclase (rim An83-91Ab17-9) constrain temperature conditions at various pressures (P at 3, 5, and 6 kb; T = 500-656°C, respectively using Holland and Blundy (1994). These conditions are consistent with amphibolite facies metamorphism. Few xenoliths retain the original igneous mineralogy (with the exception of plagioclase) but one sample contains relict “Stillwater-like” mineralogy (e.g., clinopyroxene) and another contains chromite. Plagioclase and relict clinopyroxene compositions are somewhat comparable to Stillwater mineral compositions. The fact that the xenoliths are now metamorphosed and highly altered suggests that either they were metamorphosed prior to their inclusion in the melt or were metamorphosed or hydrothermally altered as a result of incorporation into the melt

    Immunocompromise in Gnotobiotic Pigs Induced by Verotoxin-Producing \u3ci\u3eEscherichia coli\u3c/i\u3e (O111:NM)

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    A verotoxin-producing Escherichia coli serotype O111:NM strain (strain 10049; verotoxin 1 positive) persistently infected experimentally inoculated gnotobiotic pigs, causing attaching-effacing intestinal lesions and chronic diarrhea. Experiments were performed to determine whether persistent infection might be associated with immunocompromise of the host by this organism. Pigs inoculated with this strain had a significant reduction in peripheral blood lymphocytes and lower antibody titers to sheep erythrocytes compared with control pigs. Compared with pigs given a verotoxin-negative pathogenic strain of the same serotype (O111:NM, strain 2430), pigs inoculated with the verotoxin-positive strain had lower peripheral lymphocyte counts and proliferative responses to concanavalin A, phytohemagglutinin, and pokeweed mitogens. The results of this study suggest that strain 10049 has an immunocompromising effect on gnotobiotic pigs

    Immunocompromise in Gnotobiotic Pigs Induced by Verotoxin-Producing \u3ci\u3eEscherichia coli\u3c/i\u3e (O111:NM)

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    A verotoxin-producing Escherichia coli serotype O111:NM strain (strain 10049; verotoxin 1 positive) persistently infected experimentally inoculated gnotobiotic pigs, causing attaching-effacing intestinal lesions and chronic diarrhea. Experiments were performed to determine whether persistent infection might be associated with immunocompromise of the host by this organism. Pigs inoculated with this strain had a significant reduction in peripheral blood lymphocytes and lower antibody titers to sheep erythrocytes compared with control pigs. Compared with pigs given a verotoxin-negative pathogenic strain of the same serotype (O111:NM, strain 2430), pigs inoculated with the verotoxin-positive strain had lower peripheral lymphocyte counts and proliferative responses to concanavalin A, phytohemagglutinin, and pokeweed mitogens. The results of this study suggest that strain 10049 has an immunocompromising effect on gnotobiotic pigs

    Modeling the transboundary risk of feed ingredients contaminated with porcine epidemic diarrhea virus

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    Citation: Dee, S., Neill, C., Singrey, A., Clement, T., Cochrane, R., Jones, C., . . . Nelson, E. (2016). Modeling the transboundary risk of feed ingredients contaminated with porcine epidemic diarrhea virus. Bmc Veterinary Research, 12, 12. doi:10.1186/s12917-016-0674-zBackground: This study describes a model developed to evaluate the transboundary risk of PEDV-contaminated swine feed ingredients and the effect of two mitigation strategies during a simulated transport event from China to the US. Results: Ingredients imported to the USA from China, including organic & conventional soybeans and meal, lysine hydrochloride, D-L methionine, tryptophan, Vitamins A, D & E, choline, carriers (rice hulls, corn cobs) and feed grade tetracycline, were inoculated with PEDV. Control ingredients, and treatments (ingredients plus a liquid antimicrobial (SalCURB, Kemin Industries (LA) or a 2 % custom medium chain fatty acid blend (MCFA)) were tested. The model ran for 37 days, simulating transport of cargo from Beijing, China to Des Moines, IA, US from December 23, 2012 to January 28, 2013. To mimic conditions on land and sea, historical temperature and percent relative humidity (% RH) data were programmed into an environmental chamber which stored all containers. To evaluate PEDV viability over time, ingredients were organized into 1 of 4 batches of samples, each batch representing a specific segment of transport. Batch 1 (segment 1) simulated transport of contaminated ingredients from manufacturing plants in Beijing (day 1 post-contamination (PC)). Batch 2 (segments 1 and 2) simulated manufacturing and delivery to Shanghai, including time in Anquing terminal awaiting shipment (days 1-8 PC). Batch 3 (segments 1, 2 and 3) represented time in China, the crossing of the Pacific and entry to the US at the San Francisco, CA terminal (day 1-27 PC). Batch 4 (segments 1-4) represented the previous events, including transport to Des Moines, IA (days 1-37 PC). Across control (non-treated) ingredients, viable PEDV was detected in soybean meal (organic and conventional), Vitamin D, lysine hydrochloride and choline chloride. In contrast, viable PEDV was not detected in any samples treated with LA or MCFA. Conclusions: These results demonstrate the ability of PEDV to survive in a subset of feed ingredients using a model simulating shipment from China to the US. This is proof of concept suggesting that contaminated feed ingredients could serve as transboundary risk factors for PEDV, along with the identification of effective mitigation options
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