The Compact Linear Collider (CLIC) - 2018 Summary Report

The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear $e^+e^-$ collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years

Essential metal contents in indigenous gammarids related to exposure levels at the river basin scale: Metal-dependent models of bioaccumulation and geochemical correlations

Biomonitoring, assumed to be an integrative measurement of the chemical exposure of aquatic organisms, is not straightforward for essential metals because they can be actively regulated by animals. Although increasing bioaccumulation with exposure levels is a crucial endpoint for the development of biomonitors, it is rarely verified in real environments, where the metal concentrations are rather low and vary little. This study was designed at the scale of a river basin to assess the ability of Gammarus pulex indigenous populations to accumulate Cu, Zn and Mn in realistic exposure conditions. During two annual campaigns, water and gammarids were collected at various sites contrasted in terms of physicochemistry and contamination. The results show significant relationships between metal concentrations in animals and in freshwaters established by conceptual models of bioaccumulation, but with patterns specific to each metal (base level, internal regulation and maximal accumulation). In particular, a saturation process of Cu accumulation occurs at environmental exposure levels, unlike Mn and Zn. Statistical analyses performed from field data show that Cu and Zn bioaccumulations may be influenced by a complex combination of geochemical variables, unlike Mn. We conclude that G. pulex is a useful candidate to monitor metal bioavailability in freshwaters due to its responsiveness to low exposures of surrounding environments. Nevertheless, a reliable quantification of bioavailability of essential metals requires characterizing some geochemical effects on metal bioaccumulation

Ecodynamics and bioavailability of metal contaminants in a constructed wetland within an agricultural drained catchment

International audienceConstructed wetlands are designed to mitigate nutrient and pesticide fluxes from agricultural catchments. Nevertheless, information on their efficiency in removing non-degradable contaminants such as metals is still scarce. This study aimed to explore the metallic signature and fate of metals within the Rampillon wetland (France) receiving water from a drained 355-ha catchment under intensive agriculture. Original monitoring coupling classic, time-integrated and bioaccumulation-based tools was achieved to characterise spatiotemporal dynamics of various metals (As, Cd, Cr, Co, Cu, Mn, Ni, Pb, Sb, Se and Zn). To assess metal inflows and mitigation, samples of dissolved and particulate metals were collected bimonthly at the inlet and outlet of the wetland over 3 months. Simultaneously, time-integrated (sediment traps and passive samplers) and bioaccumulation-based (caged gammarids and biofilms) tools were deployed to monitor temporal changes in metal speciation and bioavailability. To gain insight into the spatial distribution of metals between abiotic and biotic matrices, sediments and indigenous invertebrates with contrasted ecologies were sampled in different cells of the wetland. The results showed time-integrated tools were more suitable than bimonthly samples to quantify metal mitigations because of temporal fluctuations and low contamination levels. Significant mitigations were thus observed in trapped sediments for all metals (ranged 11–23%, except Mn) as well as in the DGT-labile fraction for Cd, Cr, Co, Mn and Ni (ranged 13–51%). Bioaccumulation levels in biofilms also revealed a decrease in metal bioavailability at the outlet. Furthermore, the spatial survey supported the central role of sediments in metal trapping and the beneficial effect of this wetland for local biodiversity in terms of exposure. To conclude, this study provides valuable information on the ecodynamics and bioavailability of metals required for sustainable management of such artificial ecosystems and furthermore, of agricultural areas

Selective homodimerization of unprotected peptides using hybrid hydroxydimethylsilane derivatives

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Interest in the development of a soil composite indicator to establish risk models

Interest in the development of a soil composite indicator to establish risk models. Meeting on Soil and Wetland Ecotoxicology (SOWETOX 2007