33 research outputs found

    CoastColour Round Robin datasets: A data base to evaluate the performance of algorithms for the retrieval of water quality parameters in coastal waters

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    The use of in situ measurements is essential in the validation and evaluation of the algorithms that provide coastal water quality data products from ocean colour satellite remote sensing. Over the past decade, various types of ocean colour algorithms have been developed to deal with the optical complexity of coastal waters. Yet there is a lack of a comprehensive intercomparison due to the availability of quality checked in situ databases. The CoastColour Round Robin (CCRR) project, funded by the European Space Agency (ESA), was designed to bring together three reference data sets using these to test algorithms and to assess their accuracy for retrieving water quality parameters. This paper provides a detailed description of these reference data sets, which include the Medium Resolution Imaging Spectrometer (MERIS) level 2 match-ups, in situ reflectance measurements, and synthetic data generated by a radiative transfer model (HydroLight). These data sets, representing mainly coastal waters, are available from doi:10.1594/PANGAEA.841950. The data sets mainly consist of 6484 marine reflectance (either multispectral or hyperspectral) associated with various geometrical (sensor viewing and solar angles) and sky conditions and water constituents: total suspended matter (TSM) and chlorophyll a (CHL) concentrations, and the absorption of coloured dissolved organic matter (CDOM). Inherent optical properties are also provided in the simulated data sets (5000 simulations) and from 3054 match-up locations. The distributions of reflectance at selected MERIS bands and band ratios, CHL and TSM as a function of reflectance, from the three data sets are compared. Match-up and in situ sites where deviations occur are identified. The distributions of the three reflectance data sets are also compared to the simulated and in situ reflectances used previously by the International Ocean Colour Coordinating Group (IOCCG, 2006) for algorithm testing, showing a clear extension of the CCRR data which covers more turbid waters.JRC.H.1-Water Resource

    Autoantibodies against type I IFNs in patients with life-threatening COVID-19

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    Interindividual clinical variability in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is vast. We report that at least 101 of 987 patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia had neutralizing immunoglobulin G (IgG) autoantibodies (auto-Abs) against interferon-w (IFN-w) (13 patients), against the 13 types of IFN-a (36), or against both (52) at the onset of critical disease; a few also had auto-Abs against the other three type I IFNs. The auto-Abs neutralize the ability of the corresponding type I IFNs to block SARS-CoV-2 infection in vitro. These auto-Abs were not found in 663 individuals with asymptomatic or mild SARS-CoV-2 infection and were present in only 4 of 1227 healthy individuals. Patients with auto-Abs were aged 25 to 87 years and 95 of the 101 were men. A B cell autoimmune phenocopy of inborn errors of type I IFN immunity accounts for life-threatening COVID-19 pneumonia in at least 2.6% of women and 12.5% of men

    Spectra of a shallow sea-unmixing for class identification and monitoring of coastal waters

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    Ocean colour-based monitoring of water masses is a promising alternative to monitoring concentrations in heterogeneous coastal seas. Fuzzy methods, such as spectral unmixing, are especially well suited for recognition of water masses from their remote sensing reflectances. However, such models have not yet been applied for water classification and monitoring. In this study, a fully constrained endmember model with simulated endmembers was developed for water class identification in the shallow Wadden Sea and adjacent German Bight. Its performance was examined on in situ measured reflectances and on MERIS satellite data. Water classification by means of unmixing reflectance spectra proved to be successful. When the endmember model was applied to MERIS data, it was able to visualise well-known spatial, tidal, seasonal, and wind-related variations in optical properties in the heterogeneous Wadden Sea. Analyses show that the method is insensitive to small changes in endmembers. Therefore, it can be applied in similar coastal areas. For use in open ocean situations or coastal or inland waters with other specific inherent optical properties, re-simulation of the endmember spectra with local optical properties is required. However, such an adaptation requires only a limited number of local in situ measurements

    Electrocatalyzed synthesis of polypeptides on platinum surface in concentrated glycine electrolytes and ab initio calculations coupled to spectroscopic analysis

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    International audienceThe anodic oxidation of glycine in aqueous electrolyte on smooth platinum electrode was carried out by electrochemical quartz crystal microbalance coupled to cyclic voltammetry technique. Here, we performed electrochemical experiments in concentrated glycine-based electrolyte. Contrary to studies made in diluted medium, the reaction we describe leads to a strongly grafted polymer on the surface at pH values superior to 6, and up to 13, in an irreversible way. The electrodeposited mass is even very significant at pH 13. Several methods such as AFM topography and spectroscopic techniques were performed to characterize the resulting coating. The polymer growth in alkaline conditions during the anodic oxidation of glycine in water probably involves an electrocatalytic step. We showed the presence of amide bonds and then polypeptide formation on the smooth platinum surface. Periodic ab initio calculations on polyglycine II were performed and compared to XPS and vibrational spectr

    Du diagnostic de bassin versant aux actions d'atténuation: quelques retours d'expériences visant à réduire les transferts hydriques de contaminants et notamment de phytosanitaires

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    45e congrès du Groupe Français des Pesticides, Versailles, FRA, 27-/05/2015 - 29/05/2015National audiencePour les territoires identifiés en risques forts vis à vis du ruissellement par la méthode ARPEGES (Irstea-ONEMA, 2013 ; figure 1), les contraintes d'emploi des produits phytosanitaires vont constituer un vrai défi dans les années à venir : interdiction ou limitation d'emploi sur sols drainés, nécessité de mise en place de dispositifs végétalisés permanents de 5 m ou 20 m en bordure des points d'eau. D'autant que dans ces régions, les contraintes hydriques des sols limitent souvent les possibilités de rotation et parfois d'introduction de cultures de printemps. La gestion des résistances des adventices aux herbicides est également un enjeu fort qui nécessite le recours durable à des modes d'action diversifiés
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