5,847 research outputs found

    ACSIS Atlantic Ocean medium resolution SST dataset: Reconstructed 5‐day, ½‐degree, Atlantic Ocean SST (1950‐2014)

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    A new dataset, the ACSIS Atlantic Ocean medium resolution SST dataset, is presented. This new dataset spans the period 1950–2014 at a 5‐day, ½‐degree resolution and covers the Atlantic Ocean. The dataset is based on in situ sea surface temperature (SST) observations from the International Comprehensive Ocean‐Atmosphere Data Set interpolated using Kriging to infill gaps and is available from the Centre for Environmental Data Analysis (CEDA) archive. Compared to existing datasets, the resolution is increased by a factor of 4 spatially and 6 temporally

    Pyrolysis-Catalytic-Dry Reforming of Waste Plastics and Mixed Waste Plastics for Syngas Production

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    The CO2 dry reforming of various types of waste plastics (LDPE, HDPE, PS, PET, and PP) and a simulated mixture of the different waste plastics was investigated over a Ni–Co–Al catalyst using a two-stage reactor. The first stage pyrolyzed the plastics, and the second stage involved catalytic-dry reforming of the product pyrolysis gases with CO2. The introduction of CO2 without a catalyst markedly increased the dry reforming reaction and significantly improved the production of H2/CO synthesis gas (syngas). The introduction of the Ni–Co–Al catalyst further significantly improved the production of syngas. LDPE produced the highest yield of syngas at 154.7 mmolsyngas g–1plastic from the pyrolysis-catalytic-dry reforming process. The order of syngas production for the different plastics was LDPE < HDPE < PP < PS < PET. The syngas yield from the processing of the simulated waste plastic mixture was 148.6 7 mmolsyngas g–1plastic which reflected the high content of the linear polyalkene plastics (LDPE, HDPE, PP) in the simulated waste plastic mixture

    Fast pyrolysis of halogenated plastics recovered from waste computers

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    The disposal of waste computers is an issue that is gaining increasing interest around the world. In this paper, results from the fast pyrolysis in a fluidized bed reactor of three different waste computer monitor casings composed of mainly acrylonitrile-butadiene-styrene (ABS) copolymer and two different waste computer body casings composed of mostly poly(vinyl chloride) (PVC) type polymers are presented. Preliminary characterization of the waste plastics was investigated using coupled thermogravimetric analysis-Fourier transform infrared spectrometry (TGA-FT-IR). The results showed that the plastics decomposed in two stages. For the ABS-containing monitor casings, aromatic and aliphatic material were released in the first and second stages. The PVC-containing computer body casing samples showed a first-stage evolution of HCl and a second stage evolution of aromatic and aliphatic material and further HCl. In addition, each of the five plastics was fast-pyrolyzed in a laboratory-scale fluidized bed reactor at 500 °C. The fluidized bed pyrolysis led to the conversion of most of the plastics to pyrolysis oil, although the two PVC computer body cases produced large quantities of HCl. The pyrolysis oils were characterized by GC-MS and it was found that they were chemically very heterogeneous and contained a wide range of aliphatic, aromatic, halogenated, oxygenated, and nitrogenated compounds

    Shwartzman reaction after human renal homotransplantation.

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    In three human recipients, five renal homografts were destroyed within a few minutes to hours after their revascularization in the new host. The kidneys, removed one to 54 days later, had cortical necrosis. The major vessels were patent, but the arterioles and glomeruli were the site of fibrin deposition. There was little or no fixation of host immunoglobulins in the homografts. The findings were characteristic of a generalized Shwartzman reaction. Although the cause (or causes) of the Shwartzman reaction in our patients is not known, they may have been conditioned by the bacterial contamination and hemolysis that often attend hemodialysis, by immunosuppression and by the transplantation itself. Some of the patients have preformed lymphocytotoxic antibodies. Thus, certain patients may be predisposed. High-risk patients should be recognized and treated prophylactically with anticoagulants

    Correction: The Complete Sequence of the Acacia ligulata Chloroplast Genome Reveals a Highly Divergent clpP1 Gene

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    The authors would like to amend this article based on the discovery that the originally published Acacia ligulata sequence contains assembly errors, which came to light after the publication of the article

    Integration of complete chloroplast genome sequences with small amplicon datasets improves phylogenetic resolution in Acacia

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    Combining whole genome data with previously obtained amplicon sequences has the potential to increase the resolution of phylogenetic analyses, particularly at low taxonomic levels or where recent divergence, rapid speciation or slow genome evolution has resulted in limited sequence variation. However, the integration of these types of data for large scale phylogenetic studies has rarely been investigated. Here we conduct a phylogenetic analysis of the whole chloroplast genome and two nuclear ribosomal loci for 65 Acacia species from across the most recent Acacia phylogeny. We then combine this data with previously generated amplicon sequences (four chloroplast loci and two nuclear ribosomal loci) for 508 Acacia species. We use several phylogenetic methods, including maximum likelihood bootstrapping (with and without constraint) and ExaBayes, in order to determine the success of combining a dataset of 4000 bp with one of 189,000 bp. The results of our study indicate that the inclusion of whole genome data gave a far better resolved and well supported representation of the phylogenetic relationships within Acacia than using only amplicon sequences, with the greatest support observed when using a whole genome phylogeny as a constraint on the amplicon sequences. Our study therefore provides methods for optimal integration of genomic and amplicon sequences

    Paper Session II-D - The Collaborative Ukrainian Experiment: (CUE): Opportunities for Collaboration in Science Education and Research

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    In 1994, President Clinton of the United States (US) and President Kuchma of Ukraine signed an agreement to support joint activities in space. The National Aeronautics and Space Administration (NASA) and the National Space Agency of Ukraine (NSAU) have developed a joint Space Shuttle mission which will include a Ukrainian Payload Specialist. The Collaborative Ukrainian Experiment (CUE) Mission is targeted for late 1997 and features a number of plant experiments to be carried in plant growth hardware on the Space Shuttle in the middeck. In conjunction with these experiments, an educational component called the CUE TSIPS (Teachers and Students Investigating Plants in Space) is being developed for high school classrooms to participate in the experiment by performing ground-controls. Teachers in both Ukraine and the U.S. have been trained in the protocols of the Brassica-Seed Terminal growth In Chambers (B-STIC) experiment. This experiment was developed by Dr. Mary Musgrave at Louisiana State University and designed to investigate the microgravity effects on pollination and fertilization

    Paper Session III-D - The Collaborative Ukrainian Experiment

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    The Collaborative Ukrainian Experiment (CUE) flew aboard the Space Shuttle Columbia on Mission STS-87. The educational component, entitled “Teachers and Students Investigating Plants in Space” (TSIPS), involved students and teachers in the U.S. and Ukraine performing ground controls for the “Brassica rapa-Seed Terminal growth In Chamber” (B-STIC) experiment. Teachers in both countries were trained in the experimental protocols for culturing and pollinating Brassica rapa plants in simulated flight hardware. Teachers and students in the two countries have been exchanging letters which has resulted in a rich exchange of culture and science. For the mission, an Ukrainian Payload Specialist (PS) performed pollination in space while an alternate Ukrainian PS and hundreds of thousands of students in the U.S. and Ukraine performed the same tasks on Earth. Two communication downlink sessions were held so that students asked the PS about the experiments taking place on orbit. Participating students submitted the results of their ground control studies which are being compared to the plants pollinated on orbit. The enthusiasm observed from the teachers and students from both countries indicate there is great hope that the collaborations established during this mission will continue in other collaborative areas into the future

    Demyelination and axonal preservation in a transgenic mouse model of Pelizaeus-Merzbacher disease

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    It is widely thought that demyelination contributes to the degeneration of axons and, in combination with acute inflammatory injury, is responsible for progressive axonal loss and persistent clinical disability in inflammatory demyelinating disease. In this study we sought to characterize the relationship between demyelination, inflammation and axonal transport changes using a Plp1-transgenic mouse model of Pelizaeus-Merzbacher disease. In the optic pathway of this non-immune mediated model of demyelination, myelin loss progresses from the optic nerve head towards the brain, over a period of months. Axonal transport is functionally perturbed at sites associated with local inflammation and 'damaged' myelin. Surprisingly, where demyelination is complete, naked axons appear well preserved despite a significant reduction of axonal transport. Our results suggest that neuroinflammation and/or oligodendrocyte dysfunction are more deleterious for axonal health than demyelination per se, at least in the short ter

    Black carbon physical and optical properties across northern India during pre-monsoon and monsoon seasons

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    Black carbon (BC) is known to have major impacts on both climate and human health and is therefore of global importance, particularly in regions close to large populations that have strong sources. The size-resolved mixing state of BC-containing particles was characterised using a single-particle soot photometer (SP2). The study focusses on the Indo-Gangetic Plain (IGP) during the pre-monsoon and monsoon seasons. Data presented are from the UK Facility for Airborne Atmospheric Measurements BAe-146 research aircraft that performed flights during the pre-monsoon (11 and 12 June) and monsoon (30 June to 11 July) seasons of 2016. Over the IGP, BC mass concentrations were greater (1.95 µg m−3) compared to north-west India (1.50 µg m−3) and north-east India (0.70 µg m−3) during the pre-monsoon season. Across northern India, two distinct BC modes were recorded; a mode of small BC particles (core diameter <0.16 µm and coating thickness <50 nm) and a mode of moderately coated BC (core diameter <0.22 µm and coating thickness of 50–200 nm). The IGP and north-east India locations exhibited moderately coated black carbon particles with enhanced coating thicknesses, core sizes, mass absorption cross sections, and scattering enhancement values compared to much lower values present in the north-west. The coating thickness and mass absorption cross section increased with altitude (13 %) compared to those in the boundary layer. As the monsoon arrived across the region, mass concentration of BC decreased over the central IGP and north-east locations (38 % and 28 % respectively), whereas for the north-west location BC properties remained relatively consistent. Post-monsoon onset, the coating thickness, core size, mass absorption cross section, and scattering enhancement values were all greatest over the central IGP much like the pre-monsoon season but were considerably reduced over both north-east and north-west India. Increases in mass absorption cross section through the atmospheric column were still present during the monsoon for the north-west and central IGP locations, but less so over the north-east due to lack of long-range transport aerosol aloft. Across the Indo-Gangetic Plain and north-east India during the pre-monsoon and monsoon seasons, solid-fuel (wood burning) emissions form the greatest proportion of BC with moderately coated particles. However, as the monsoon develops in the north-east there was a switch to small uncoated BC particles indicative of traffic emissions, but the solid-fuel emissions remained in the IGP into the monsoon. For both seasons in the north-west, traffic emissions form the greatest proportion of BC particles. Our findings will prove important for greater understanding of the BC physical and optical properties, with important consequences for the atmospheric radiative forcing of BC-containing particles. The findings will also help constrain the regional aerosol models for a variety of applications such as space-based remote sensing, chemistry transport modelling, air quality, and BC source and emission inventories
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