1,445 research outputs found

    Oscillatory subglacial drainage in the absence of surface melt

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    The presence of strong diurnal cycling in basal water pressure records obtained during the melt season is well established for many glaciers. The behaviour of the drainage system outside the melt season is less well understood. Here we present borehole observations from a surge-type valley glacier in the St Elias Mountains, Yukon Territory, Canada. Our data indicate the onset of strongly correlated multi-day oscillations in water pressure in multiple boreholes straddling a main drainage axis, starting several weeks after the disappearance of a dominant diurnal mode in August 2011 and persisting until at least January 2012, when multiple data loggers suffered power failure. Jökulhlaups provide a template for understanding spontaneous water pressure oscillations not driven by external supply variability. Using a subglacial drainage model, we show that water pressure oscillations can also be driven on a much smaller scale by the interaction between conduit growth and distributed water storage in smaller water pockets, basal crevasses and moulins, and that oscillations can be triggered when water supply drops below a critical value. We suggest this in combination with a steady background supply of water from ground water or englacial drainage as a possible explanation for the observed wintertime pressure oscillations

    Community Dynamics of Phytoplankton in a Typical Navigation Pool in the Upper Mississippi River

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    In 1986 we studied phytoplankton in the mid-reaches of Pool 8, which is a typical navigation pool of the Upper Mississippi River. During years of normal discharge, the areas studied usually become distinctly different from each other (ranging from free-flowing river to stagnant marsh) as the ice-free season progresses. These differences among sites did not occur during our study because the discharge into Pool 8 during 1986 was about 85% greater than the 10-yr mean discharge (1972-1982). Moreover, differences among areas were not observed with respect to physical and chemical characteristics such as photic zone depth, temperature, dissolved nitrogen and phosphorus, and silica. Accordingly, the phytoplankton assemblages and standing crops, which were characteristic of eutrophic waters, remained similar for all study areas. The phytoplankton was dominated by centric diatoms (Melosira granulata, M. italica, Stephanodiscus astrea, and Cyclotella meneghiniana), which comprised about 70% of the total cell volume. Aphanizomenon flos-aquae, Cryptomonas ovata, and U lothrix subconstricta were the most abundant non-diatoms; however, dense blooms of Aphanizomenon that normally occur in the Upper Mississippi River did not occur during the summer of 1986. Of the physical and chemical characteristics studied, discharge and temperature were most highly correlated with phytoplankton cell volume and chlorophyll a. In contrast, phosphorus and nitrogen were not correlated with phytoplankton standing crop

    Technology for large-scale translation of clinical practice guidelines : a pilot study of the performance of a hybrid human and computer-assisted approach

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    Background: The construction of EBMPracticeNet, a national electronic point-of-care information platform in Belgium, was initiated in 2011 to optimize quality of care by promoting evidence-based decision-making. The project involved, among other tasks, the translation of 940 EBM Guidelines of Duodecim Medical Publications from English into Dutch and French. Considering the scale of the translation process, it was decided to make use of computer-aided translation performed by certificated translators with limited expertise in medical translation. Our consortium used a hybrid approach, involving a human translator supported by a translation memory (using SDL Trados Studio), terminology recognition (using SDL Multiterm termbases) from medical termbases and support from online machine translation. This has resulted in a validated translation memory which is now in use for the translation of new and updated guidelines. Objective: The objective of this study was to evaluate the performance of the hybrid human and computer-assisted approach in comparison with translation unsupported by translation memory and terminology recognition. A comparison was also made with the translation efficiency of an expert medical translator. Methods: We conducted a pilot trial in which two sets of 30 new and 30 updated guidelines were randomized to one of three groups. Comparable guidelines were translated (a) by certificated junior translators without medical specialization using the hybrid method (b) by an experienced medical translator without this support and (c) by the same junior translators without the support of the validated translation memory. A medical proofreader who was blinded for the translation procedure, evaluated the translated guidelines for acceptability and adequacy. Translation speed was measured by recording translation and post-editing time. The Human Translation Edit Rate was calculated as a metric to evaluate the quality of the translation. A further evaluation was made of translation acceptability and adequacy. Results: The average number of words per guideline was 1,195 and the mean total translation time was 100.2 min/1,000 words. No meaningful differences were found in the translation speed for new guidelines. The translation of updated guidelines was 59 min/1,000 words faster (95% CI 2-115; P=.044) in the computer-aided group. Revisions due to terminology accounted for one third of the overall revisions by the medical proofreader. Conclusions: Use of the hybrid human and computer-aided translation by a non-expert translator makes the translation of updates of clinical practice guidelines faster and cheaper because of the benefits of translation memory. For the translation of new guidelines there was no apparent benefit in comparison with the efficiency of translation unsupported by translation memory (whether by an expert or non-expert translator

    Critical analysis of strategies for PM reduction in urban areas

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    This paper presents an overview of practical strategies that can be adopted for reducing the particulate matter concentration in urban areas. Each strategy is analyzed taking into account the latest results of the scientific literature. A discussion useful for pointing out some problems to be solved for their correct adoptions completes the paper

    Association d’une encéphalomyélite aiguë disséminée et syndrome de Guillain-Barré chez l’enfant

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    L'encéphalomyélite aiguë disséminée (ADEM) et le syndrome de Guillain-Barré (SGB) sont des troubles neuro-inflammatoires qui surviennent après une infection ou vaccination, affectant le système nerveux central (SNC) et le système nerveux périphérique (SNP), respectivement. L'association d'une atteinte immunologique simultanée du SNC et du SNP est rare. Nous présentons le cas d'une fille de 5 ans sans antécédents pathologiques particuliers, qui a présenté suite à un épisode de diarrhées liquidiennes, un déficit des membres inférieurs ascendant, bilatéral et symétrique. L'examen clinique avait montré une tétraplégie, une anesthésie thermo-algique des deux membres inférieurs et une abolition des reflexes ostéotendineux. Le diagnostic de syndrome de Guillain Barrée était suspecté. La ponction lombaire était non concluante. L'électroneuromyogramme était en faveur d'une polyneuropathie axonale sensitivomotrice. L'évolution était marquée par l'apparition d'une détresse respiratoire et de troubles de déglutition, ayant nécessité l'hospitalisation en réanimation pendant cinq jours. Par la suite, la patiente avait développé, des céphalées intenses avec des troubles visuels et une incontinence urinaire. L'examen des paires crâniennes avait montré une cécité bilatérale avec une paralysie faciale centrale droite. Le réflexe cutanéo-plantaire était en extension (Babinski bilatérale). L'imagerie par résonance magnétique (IRM) a mis en évidence la présence de foyers de démyélinisation au niveau de la substance blanche et des noyaux gris centraux en faveur de l'ADEM. La patiente a été mise sous méthylprédnisolone 30 mg/kg/j en boulus pendant 3 jours puis corticothérapie 2mg/kg/J pendant 4 semaines avec une bonne évolution

    Municipal Solid Waste treatment by integrated solutions: energy and environmental balances

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    This paper reports a comparison between two scenarios developed in order to manage the municipal solid waste in an area in the North part of Italy. In the proposed scenarios various technological solutions, regarding the selective collection, the energy recovery and the modality of final disposal were taken into account. The comparison was done considering both mass/energy and environmental balance, trying to focus the most suitable solution. The experience can be completed with other scenarios containing different technical solution intermediate between the two considered in this study

    PCDD/F Emissions From Virgin And Treated Wood Combustion

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    Energy from biomass is becoming increasingly important as fossil fuel reserves diminish. The utilization of biomass is already prevalent in the domestic heating sector, but produces significant amounts of pollutants that are detrimental to human health. Dioxins, formed in any combustion process where carbon, oxygen and, chlorine are present, are a subject of major interest due to their carcinogenicity. Much research has been carried out to study emissions from hazardous and municipal waste incinerators. Dioxin emission from wood combustion plants are also of interest, especially those due to combustion of treated, varnished or PVC-coated wood, which can produce high polychlorinated dibenzofurans (PCDD/F) emissions. This study compares the PCDD/F emissions produced by burning treated wood and virgin wood to verify if the differences are significant. Six different wood samples were analysed (three of treated wood and three of virgin wood) and a two-step wood gasification boiler was used. The analysis has been conducted both on off gas and on ashes. The measured PCDD/F concentrations are to be considered particularly limited and the treated wood use does not cause a general worsening in the PCDD/F emission. Thus, the wood treatment – subject of study – is not dangerous for PCDD/F. Finally, the experimental results indicated that during the thermal treatment, the formation mechanism of PCDD/F is the de novo synthesis

    A protocol for developing, disseminating, and implementing a core outcome set (COS) for childbirth pelvic floor trauma research.

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    BACKGROUND: More than 85% of women sustain different degrees of trauma during vaginal birth. Randomized controlled trials on childbirth pelvic floor trauma have reported a wide range of outcomes and used different outcome measures. This variation restricts effective data synthesis, impairing the ability of research to inform clinical practice. The development and use of a core outcome set (COS) for childbirth pelvic floor trauma aims to ensure consistent use of outcome measures and reporting of outcomes. METHODS: An international steering group, within CHORUS, an International Collaboration for Harmonising Outcomes, Research and Standards in Urogynaecology and Women's Health, including academic community members, researchers, healthcare professionals, policy makers and women with childbirth pelvic floor trauma will lead the development of this COS. Relevant outcome parameters will be identified through comprehensive literature reviews. The selected outcomes will be entered into an international, multi-perspective online Delphi survey. Subsequently and based on the results of the Delphi surveys consensus will be sought on 'core' outcomes. DISCUSSION: Dissemination and implementation of the resulting COS within an international context will be supported and promoted. Embedding the COS for childbirth pelvic floor trauma within future clinical trials, systematic reviews, and clinical practice guidelines is expected to enrich opportunities for comparison of future clinical trials and allow better synthesis of outcomes, and will enhance mother and child care. The infrastructure created by developing a COS for childbirth pelvic floor trauma could be leveraged in other settings, for example, advancing research priorities and clinical practice guideline development

    Cotorsion Pairs in C(R-Mod)

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    In [8] Salce introduced the notion of a co-torsion pair (A, B) in the category of abelian groups. But his definitions and basic results carry over to more general abelian categories and have proved useful in a variety of settings. In this article we will consider complete cotorsion pairs (C, D)in the category C(R-Mod) of complexes of left R-modules over some ring R.If(C, D) is such a pair, and if C is closed un-der taking suspensions, we will show when we regard K(C) and K(D) as subcategories of the homotopy category K(R-Mod), then the embedding functors K(C) → K(R-Mod) and K(D) → K(R-Mod) have left and right adjoints, respectively. In finding examples of such pairs, we will describe a procedure for using Hoveys results in [5] to find a new model structure on C(R-Mod)

    Characterization of the PCDD/F in the Province of Trento

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    Abstract This paper aims to improve the already existing literature data on air concentrations of polychlorinated dibenzo- p -dioxin and dibenzofurans (PCDD/Fs). Four monitoring campaigns were carried out between 2002 and 2010 near Trento, a town in the North of Italy. These campaigns showed relatively low PCDD/F concentrations, in line with the values found in other Italian urban and industrial sites. Typical values for agricultural regions were measured in rural areas, with an increase during winter, possibly due to biomass burning. No critical situations were detected along an important highway, in spite of the non-negligible emission factors for traffic reported in the literature
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