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The most populous city of the world’s largest watershed (Manaus, Amazon Basin, Brazil) is experiencing an extensive urban expansion since the early 1970s, with an attendant cost in environmental degradation. The upland area of the Manaus municipality is characterized by several streams. In this work, we aim to gradually measure the anthropogenic effect on water quality: we monitored three streams flowing over three zones: a preserved (where the streams take source), a peri-urban (where rural and leisure activities occur), and an urban area. From June 2013 to May 2015, we characterized the water quality of these streams. Statistical analyses reveal peri-urban activity does not significantly impact the water quality. Indeed, when the disturbance remains space-, time- and intensity-limited, the streams have the capacity to assimilate the anthropogenic pollution. However, looking at a seasonal finer scale, peri-urban activity slightly affects the natural pattern of water quality, but these changes remain moderated when compared to the original pattern of water quality. Over urban area, the water quality presents significant higher alkalinity, mineralization, turbidity, suspended material, biochemical and chemical oxygen demands, and lower acidity and dissolved oxygen. These alterations originate with sewage deficiency, presence of landfill sites, enhanced leaching of upturned soil and domestic waste. The natural seasonal patterns of water quality are totally disturbed (inversion, intensification) in the urban area. During the wet season, enhanced rainfall in conjunction with human activity generates local seasonal processes of dilution (e.g. negative anomalies for most of the dissolved elements) and concentration (positive Mg and Fe anomalies). The latter can be linked with enhanced leaching during the rainy period (positive Mg and Fe anomalies) and nitrification activity in the urban area (positive NO3 and negative NH4 anomalies).

International audience; In the framework of climate changes, peatland ecosystems are compartments of the Critical Zone of growing importance for greenhouse gas (GHG) exchanges with the atmosphere. Peatlands contain about 30 % of the total organic soil carbon worldwide. Interactions of GHG between atmosphere and peatland are potentially controlled by organic matter production and degradation controlled by biotic functiuns, which are in turn influenced by diverse abiotic factors including (1) water saturation, (2) peat humification degree, and (3) water quality conditioning electron acceptor availability. Delineating the detailed roles of these mechanisms is therefore challenging for long-term peatland management, requiring a detailed spatio-temporal monitoring of a wide range of hydrological and biogeochemical parameters.The Frasne peatland (Jura mountains, eastern France), belonging to a regional natural reserve is an outstanding site for such studies as it is monitored since 2008 in the framework of the national observatory of peatlands (SNO Tourbières),and belongs to the Zones Ateliers (RZA) and French Critical Zone (OZCAR) networks supplying the Europe Long-Term Ecosystem Research (eLTER) database (DEIMS-SDR). The peatland took place in a periglacial context on groundmoraines covering a large-scale karstified synclinal structure. This complex geological setting is combined with eco-physical (peat thicknesses and maturity), and hydrological (water-table depth) heterogeneities at the peatland scale.Based on daily hydrometeorological data (P, T, potential evapotranspiration, groundwater level) and monthly monitoring (hydrochemistry; peat lability, GHG fluxes) in 25 piezometers, the goal of the CRITICAL PEAT project is to identify the hydrological and biogeochemical drivers controlling GHG exchanges between peatland and atmosphere. In this perspective, this contribution aims at presenting preliminary results on the hydroclimatic sensitivity of the system inferred from correlation analyses, and its relationships with water origin and chemistry.

Paul Retif,1–3 Aurélie Reinhard,2,3 Héna Paquot,2,3 Valérie Jouan-Hureaux,2,3 Alicia Chateau,2,3 Lucie Sancey,4 Muriel Barberi-Heyob,2,3 Sophie Pinel,2,3 Thierry Bastogne2,3,5 1Unité de Physique Médicale, CHR Metz-Thionville, Ars-Laquenexy, 2Université de Lorraine, 3CRAN, UMR7039, CNRS, Vandoeuvre-lès-Nancy, 4Institut Lumière Matière, UMR 5306, CNRS, Villeurbanne, 5INRIA-BIGS& CRAN, Université de Lorraine, Vandoeuvre-lès-Nancy Cedex, France Abstract: This article addresses the in silico–in vitro prediction issue of organometallic nanoparticles (NPs)-based radiosensitization enhancement. The goal was to carry out computational experiments to quickly identify efficient nanostructures and then to preferentially select the most promising ones for the subsequent in vivo studies. To this aim, this interdisciplinary article introduces a new theoretical Monte Carlo computational ranking method and tests it using 3 different organometallic NPs in terms of size and composition. While the ranking predicted in a classical theoretical scenario did not fit the reference results at all, in contrast, we showed for the first time how our accelerated in silico virtual screening method, based on basic in vitro experimental data (which takes into account the NPs cell biodistribution), was able to predict a relevant ranking in accordance with in vitro clonogenic efficiency. This corroborates the pertinence of such a prior ranking method that could speed up the preclinical development of NPs in radiation therapy. Keywords: biomedical applications of radiations, computer simulation, nanomedicine, virtual screening

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Current collapse in AlGaN/GaN HFETs is investigated at low temperatures using a transient current monitoring technique. The carrier trapping and de-trapping mechanisms are studied, and two distinct relaxation mechanisms are observed. They are associated to the presence of two close deep energy levels in the bandgap.

AlGaN/GaN power HFETs grown on a 200nm thick AlN sub-buffer layer are investigated. The presence of a steady kink in the static and dynamic drain-to-source current characteristics is attributed to floating-body (FB) effects that result from the AlN sub-buffer layer. A method to extract the off-state body-to-source voltage (VBS) is applied and the coherence of the results confirms that FB effects are present in this type of structures. To our knowledge, this is the first time that floating-body effects are reported and modeled in AlGaN/GaN HFETs.