From Agent to Active Sense : Was there an Augustinianism-Averroisant?

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Optimization of CABRI power transients with the SPARTE code and the URANIE uncertainty platform

International audienceIn a Pressurized Water Reactor (PWR), the rod ejection is a design basis accident for uncontrolled evolution of the nuclear reaction.In case of failure of a rod mechanism, the rod ejection is caused by the pressure differential between the primary loop (155 bar) and the confinement-s enclosure (atmospheric pressure).It leads to a local power transient and a fast fuel temperature increase.The power transient is limited by the reactivity feedbacks before the automatic reactor shutdown.The CABRI experimental pulsed reactor is funded by the French Nuclear Safety and Radioprotection Institute (IRSN) and is operated by CEA at the Cadarache research center.It is designed to study fuel rods behavior under Reactivity Initiated Accident (RIA) conditions.The tested fuel rod is placed at the center of the CABRI core, inside a pressurized water loop reproducing PWR conditions.CABRI is a pool type reactor, made of 1487 UO$_2$ fuel rods and controlled by 6 Hafnium control rods.A specific device allows the fast depressurization of $^3$He contained in 4 transient rods to reproduce control rods ejection conditions.Based on a BEPU approach, we developed a tool, named SPARTE, for CABRI power transients calculation.This tool is based on point kinetics, simplified thermal-hydraulics and thermal-mechanics.It computes the global behavior of the core by the calculation of a mean fuel rod. It includes models of reactivity insertion specific to the CABRI transient rods system, variable kinetics parameters and variable Doppler coefficient.This code is validated on the basis of 66 CABRI start-up power transients realized during the first quarter of 2017. One goal of the SPARTE code is to be used for the prediction of future CABRI power transients.This paper focuses on methods for optimizing a specific CABRI power transient (FWHM $\simeq$ 30 ms, Deposited energy $\simeq$ 130 $MJ$) using the target characteristics of the pulse. The selection of a method may help the experimentalists and the operation team to minimize the number of white- power transients to perform before the final test with the fuel sample. The optimization can lead to different results, that can be ranked according to their projected uncertainties. Different optimization methods are tested and compared in this paper. The Subplex method based on reiterations of the Nelder-Mead algorithm (simplex method) was selected for its high precision. Indeed, the CABRI power transients are not completely reproducible and present some uncertainties linked to the test parameters. This article focuses on the uncertainties propagation in order to identify and select the parameters that minimize the output uncertainties. The results are very satisfactory and lead to several optimized scenarios that will be tested during the next qualification test campaign

Repeated genomic signatures of adaptation to urbanisation in a songbird across Europe

Urbanisation is currently increasing worldwide, and there is now ample evidence of phenotypic changes in wild organisms in response to this novel environment, but the extent to which this adaptation is due to genetic changes is poorly understood. Current evidence for evolution is based on localised studies, and thus lacking replicability. Here, we genotyped great tits (Parus major) from nine cities across Europe, each paired with a rural site, and provide evidence of repeated polygenic responses to urban habitats. In addition, we show that selective sweeps occurred in response to urbanisation within the same genes across multiple cities. These genetic responses were mostly associated with genes related to neural function and development, demonstrating that genetic adaptation to urbanisation occurred around the same pathways in wildlife populations across a large geographical scale.Competing Interest StatementThe authors have declared no competing interest

Reliability of Various Size Oxide Aperture VCSELs,"

Abstract This paper presents Honeywell's most recent work on 850-nm oxide aperture vertical cavity surface emitting laser (VCSEL) reliability. The VCSELs studied have a range of aperture diameters from about 5 to 20 µm and the reliability effect of aperture diameter is of principal interest in this paper. Larger apertures generally exhibit greater reliability. Electrostatic discharge (ESD) sensitivity thresholds of the various oxide aperture VCSELs is discussed, again showing dependence on diameter, with larger being better. Results for humidity exposure are presented. Here we find no aperture size dependence, because none of the tested designs show significant susceptibility to humidity-induced degradation. It is demonstrated that, in addition to end-of-life degradation, VCSELs generally exhibit variation of performance characteristics during the early part of operating life. This often leads to a requirement for device burn-in. Honeywell's work in the area of wafer stabilization (trademarked under the name STABILAZE, patent pending) is introduced, showing how critical device parameters such as threshold and slope efficiency can be made to be unvarying over the product's life without the need for costly component or module-level burnins

Environmental and Parental Influences on Offspring Health and Growth in Great Tits (Parus major)

PMCID: PMC3728352This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

The impact of cyclin-dependent kinase 5 depletion on poly(ADP-ribose) polymerase activity and responses to radiation

Cyclin-dependent kinase 5 (Cdk5) has been identified as a determinant of sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors. Here, the consequences of its depletion on cell survival, PARP activity, the recruitment of base excision repair (BER) proteins to DNA damage sites, and overall DNA single-strand break (SSB) repair were investigated using isogenic HeLa stably depleted (KD) and Control cell lines. Synthetic lethality achieved by disrupting PARP activity in Cdk5-deficient cells was confirmed, and the Cdk5KD cells were also found to be sensitive to the killing effects of ionizing radiation (IR) but not methyl methanesulfonate or neocarzinostatin. The recruitment profiles of GFP-PARP-1 and XRCC1-YFP to sites of micro-irradiated Cdk5KD cells were slower and reached lower maximum values, while the profile of GFP-PCNA recruitment was faster and attained higher maximum values compared to Control cells. Higher basal, IR, and hydrogen peroxide-induced polymer levels were observed in Cdk5KD compared to Control cells. Recruitment of GFP-PARP-1 in which serines 782, 785, and 786, potential Cdk5 phosphorylation targets, were mutated to alanines in micro-irradiated Control cells was also reduced. We hypothesize that Cdk5-dependent PARP-1 phosphorylation on one or more of these serines results in an attenuation of its ribosylating activity facilitating persistence at DNA damage sites. Despite these deficiencies, Cdk5KD cells are able to effectively repair SSBs probably via the long patch BER pathway, suggesting that the enhanced radiation sensitivity of Cdk5KD cells is due to a role of Cdk5 in other pathways or the altered polymer levels