627 research outputs found

    Bacterial Active Community Cycling in Response to Solar Radiation and Their Influence on Nutrient Changes in a High-Altitude Wetland

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    Indexación: Web of Science; Scopus.Microbial communities inhabiting high-altitude spring ecosystems are subjected to extreme changes in solar irradiance and temperature throughout the diel cycle. Here, using 16S rRNA gene tag pyrosequencing (cDNA) we determined the composition of actively transcribing bacteria from spring waters experimentally exposed through the day (morning, noon, and afternoon) to variable levels of solar radiation and light quality, and evaluated their influence on nutrient recycling. Solar irradiance, temperature, and changes in nutrient dynamics were associated with changes in the active bacterial community structure, predominantly by Cyanobacteria, Verrucomicrobia, Proteobacteria, and 35 other Phyla, including the recently described Candidate Phyla Radiation (e.g., Parcubacteria, Gracilibacteria, OP3, TM6, SR1). Diversity increased at noon, when the highest irradiances were measured (3.3-3.9 H', 1125 W m(-2)) compared to morning and afternoon (0.6-2.8 H'). This shift was associated with a decrease in the contribution to pyrolibraries by Cyanobacteria and an increase of Proteobacteria and other initially low frequently and rare bacteria phyla (< 0.5%) in the pyrolibraries. A potential increase in the activity of Cyanobacteria and other phototrophic groups, e.g., Rhodobacterales, was observed and associated with UVR, suggesting the presence of photo activated repair mechanisms to resist high levels of solar radiation. In addition, the percentage contribution of cyanobacterial sequences in the afternoon was similar to those recorded in the morning. The shifts in the contribution by Cyanobacteria also influenced the rate of change in nitrate, nitrite, and phosphate, highlighted by a high level of nitrate accumulation during hours of high radiation and temperature associated with nitrifying bacteria activity. We did not detect ammonia or nitrite oxidizing bacteria in situ, but both functional groups (Nitrosomona and Nitrospira) appeared mainly in pyrolibraries generated from dark incubations. In total, our results reveal that both the structure and the diversity of the active bacteria community was extremely dynamic through the day, and showed marked shifts in composition that influenced nutrient recycling, highlighting how abiotic variation affects potential ecosystem functioning.http://journal.frontiersin.org/article/10.3389/fmicb.2016.01823/ful

    PSS14 Cost-Effectiveness of Biologic Therapies for the Treatment of Moderate to Severe Psoriasis in Germany

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    H2_2 [Pt(C2_2O4_4)2_2] as a Tailor‐made Halide‐free Precursor for the Preparation of Diesel Oxidation Catalysts: Nanoparticles Formation, Thermal Stability and Catalytic Performance

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    The aim of this study was to investigate a tailor-made metal precursor and its chemical properties to tune the properties of supported metal nanoparticles (NPs) and their catalytic performance when used as Diesel Oxidation Catalyst (DOC). The formation of extremely small Pt NPs from a new halide-free Pt complex was investigated, namely bis(oxalato)platinate, H2_2 [Pt(C2_2O4_4)2_2]. The size evolution of the supported NPs, from the formation upon the Pt precursor decomposition on γ-alumina to the sintering of the NPs at high temperatures, was followed by thermogravimetric analysis coupled with mass spectrometry (TG-MS) and differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. A correlation between the NPs’ size of the catalyst and the performance for the CO, C3_3H6_6, C3_3H8_8 and NO oxidation reactions pointed out a retained activity during test cycles, showing low sensitivity to the test conditions applied (i. e., temperature and gas composition). The overall catalytic performance was better in the fresh catalysts compared to the reference catalyst prepared from platinum nitrate, Pt(NO3_3)4_4. In particular, the different dispersion of the Pt NPs over the support obtained from the two precursors was identified as the reason for the different catalytic performance, retaining small NPs size after the tests cycles

    Metamorphic conditions in the Nilgiri Granulite Terrane and the adjacent Moyar and Bhavani Shear Zones: A reevaluation

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    Data were presented on pressure and temperature determinations from the Nilgiri Hills. About 70 samples were analyzed by probe and several calibrations of garnet-pyroxene thermometry and barometry applied. Most calibrations gave considerable scatter; however, a new calibration by Bhattacharya, Raith, Lal, and others, accounting for nonideality in both garnet and orthopyroxene, gave consistent results of 754 + or - 52 C and 9.2 + or - 0.7 kbar. On the regional scale, a pressure increase of 6.5 to 7 kbar in the SW to 11 kbar in the NE was related to block tilting. A continuous pressure gradient into the Moyar shear zone suggests that the zone is not a suture juxtaposing unrelated blocks

    Formation and investigation of micro-arc Sr-containing calciumphosphate biocoatings on Mg-0.8 Ca alloy

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    The investigation of the XRD analysis, thickness, masses and roughness of Sr-substituted calcium phosphate coatings on the Mg-0.8Ca substrate deposited by the micro arc oxidation method under different process voltages was performed. The increase of the process voltage leads to the growth of the thickness, masses and roughness of the coatings. Results of XRD analysis showed that the Sr-CaP coatings formed under the process voltages of 350-450 V are contained α-Ca[3](PO[4])[2], Mg[3](PO[4])[2] and Mg phases

    The PLATO Dome A Site-Testing Observatory : instrumentation and first results

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    The PLATeau Observatory (PLATO) is an automated self-powered astrophysical observatory that was deployed to Dome A, the highest point on the Antarctic plateau, in 2008 January. PLATO consists of a suite of site-testing instruments designed to quantify the benefits of the Dome A site for astronomy, and science instruments designed to take advantage of the unique observing conditions. Instruments include CSTAR, an array of optical telescopes for transient astronomy; Gattini, an instrument to measure the optical sky brightness and cloud cover statistics; DASLE, an experiment to measure the statistics of the meteorological conditions within the near-surface layer; Pre-HEAT, a submillimeter tipping radiometer measuring the atmospheric transmission and water vapor content and performing spectral line imaging of the Galactic plane; and Snodar, an acoustic radar designed to measure turbulence within the near-surface layer. PLATO has run completely unattended and collected data throughout the winter 2008 season. Here we present a detailed description of the PLATO instrument suite and preliminary results obtained from the first season of operation

    Bacterial Active Community Cycling in Response to Solar Radiation and Their Influence on Nutrient Changes in a High-Altitude Wetland

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    This research was supported by funds granted by Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile) FONDECYT grants N° 1110824, 1140179, 11110190, 1100358, 1110953, and 1140356; CONICYT-PIA FB0001
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