Delayed and time-cumulative toxicity of imidacloprid in bees, ants and termites

Imidacloprid, one of the most commonly used insecticides, is highly toxic to bees and other beneficial insects. The regulatory challenge to determine safe levels of residual pesticides can benefit from information about the time-dependent toxicity of this chemical. Using published toxicity data for imidacloprid for several insect species, we construct time-to-lethal-effect toxicity plots and fit temporal power-law scaling curves to the data. The level of toxic exposure that results in 50% mortality after time t is found to scale as t(1.7) for ants, from t(1.6) to t(5) for honeybees, and from t(1.46) to t(2.9) for termites. We present a simple toxicological model that can explain t(2) scaling. Extrapolating the toxicity scaling for honeybees to the lifespan of winter bees suggests that imidacloprid in honey at 0.25 μg/kg would be lethal to a large proportion of bees nearing the end of their life

Mechanical Analysis of the FRESCA2 Dipole During Preload, Cool-Down, and Powering

International audienceThe FRESCA2 dipole magnet is being developed within a collaboration between CEA Saclay and CERN. The main goal of the magnet is to provide a 13 T nominal bore field into a clear aperture of 100 mm diameter, for the second generation cable test facility FRESCA2 at CERN. Two magnet assemblies have been done with different coils. The assemblies have been preloaded at room temperature, cooled-down in liquid helium, and powered with several current cycles. The magnet is mechanically instrumented with strain gauges on the external shell, tie rods, and central post of the coils. Strain data are compared with a 3-D mechanical model, in order to validate different assumptions such as friction coefficients, material properties, and prestress levels. This paper reports the results of the mechanical measurements collected during preload, cool-down, powering, and warm-up of the magnet

Fabrication and Assembly of the Nb3SnNb_3Sn Dipole Magnet FRESCA2

International audienceThe FRESCA2 Dipole Magnet is developed within the framework of a collaboration between CEA Saclay and CERN, in the continuity of the European project EuCARD. The goal is to manufacture a dipole magnet providing a 13 T magnetic field in a 100 mm aperture for a superconducting cable test station at CERN. The magnet is composed of four double-layer $Nb_3Sn$ coils, arranged in a block-type configuration, with flared ends. Four $Nb_3Sn$ coils have been fabricated at CEA Saclay and CERN. This paper reports on the coil fabrication, describing the process, the issues encountered, and the solutions implemented. A series of geometrical and electrical characterizations were also performed on the coils in order to validate their quality. The coils are finally validated and ready to be assembled at CERN to form the magnet. The magnet assembly process is also described: the coils are assembled to form a coil pack, the coil pack is inserted in a shell-based support structure and pre-loaded at room temperature. The margins, expected in the different operation cases, are finally presented

Assembly of the Nb3_{3}Sn dipole magnet FRESCA2

The Nb$_{3}$Sn dipole magnet FRESCA2 has been developed and manufactured within the framework of a collaboration between the Centre for Atomic Energy (CEA Saclay) and the European Organization for Nuclear Research (CERN). The aim of the magnet is to upgrade the superconducting cable test station at CERN with a Nb$_{3}$Sn dipole providing a 13-T magnetic field in a 100-mm aperture. The magnet is composed of four coils in a block-type configuration with flared ends, 1.6 m long, housed in a bladder, and key-type mechanical structure. A first assembly of the magnet, FRESCA2a, has been done at CERN at the end of 2016 with the four first Nb$_{3}$Sn coils fabricated at CEA Saclay and CERN. The coils were dimensionally measured, and tailored shims were fabricated and inserted in the coil pack to improve the contact between layers. In addition, tests with pressure sensitive films were carried out to verify the uniformity of the loading. The magnet was cold tested in February 2017 and dismounted to replace one coil. A second assembly, FRESCA2b, was produced and tested in August 2017. In this paper, we provide a detailed description of the various steps of the assembly from the impregnated coils to the delivery of the dipole to the test facility, with a particular emphasis on the procedures followed and the tooling developed

Commensal Hafnia alvei strain reduces food intake and fat mass in obese mice—a new potential probiotic for appetite and body weight management

International audienc

Plasma Peptide Concentrations and Peptide-Reactive Immunoglobulins in Patients with Eating Disorders at Inclusion in the French EDILS Cohort (Eating Disorders Inventory and Longitudinal Survey)

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Tests of the FRESCA2 100 mm bore Nb3_3Sn block-coil magnet to a record field of 14.6 T

International audienceThe Nb$_3$Sn block coil dipole magnet FRESCA2 was developed within the framework of a collaboration between CEA Saclay and CERN, in the continuity of the European project EuCARD and EuCARD2. With an aperture of 100 mm and a target bore field of 13 T at 10.6 kA, the magnet is required for a new FRESCA2 cable test facility at CERN. In 2017, the magnet was pre-loaded to retain the forces while the magnet was powered to achieve 13.3 T in the magnet bore. Results of these tests were published. In 2018, the loading of the magnet has been increased for powering to higher current. In this paper, the updated results of the cold powering tests are discussed in terms of training, memory, and stable operation. The loading of the magnet and the mechanical measurements during cooldown are shown and compared to the earlier loading steps. The protection of the magnet is further reviewed and measured results are compared to the model simulations