Differential Privacy has Bounded Impact on Fairness in Classification

18 pagesWe theoretically study the impact of differential privacy on fairness in classification. We prove that, given a class of models, popular group fairness measures are pointwise Lipschitz-continuous with respect to the parameters of the model. This result is a consequence of a more general statement on accuracy conditioned on an arbitrary event (such as membership to a sensitive group), which may be of independent interest. We use the aforementioned Lipschitz property to prove a high probability bound showing that, given enough examples, the fairness level of private models is close to the one of their non-private counterparts

Anthropic and natural factors drive variation of survival in the red-legged partridge in southern France

International audienceUnderstanding demographical processes underlying abundance and population size fluctuations is critical to species management. Knowing key parameters and responses to observed changes can reduce the number of realistic management scenarios. In hunted species, survival might be the targeted parameter for effective plans. The red-legged partridge Alectoris rufa is a native species in Mediterranean countries. The species is hunted, especially in France where some release plans are implemented. However, survival estimates are scarce there and most studies were conducted in Spain. Here, we took advantage of a radio-tracking experiment in southern France (200 birds surveyed) to estimate monthly and annual survival rates of both wild and released red-legged partridge and to investigate the temporal, spatial and individual variations in survival. We found very high annual survival rate in our island site (0.70) and low survival elsewhere (range: 0.25–0.29). We showed that age and sex were a significant source of variation in annual survival of wild birds with lower estimates for young and for females. The close survival between mainland sites with different mortality sources suggests that compensation may occur between predation and hunting mortality. However, a stronger assessment of this point is needed. Our study suggests that environment characteristics, especially landscape mosaic and predation pressure, was a driver of survival. On the island site, the red-legged partridge shows a different demographic tactics (higher survival, lower reproduction) than in mainland, suggesting an adaptation to the context (lower predation). Regarding hand-reared birds released just before the hunting season, their survival to the next spring was lower than 0.05. Such a low value raises the issue of using release before the hunting season for reinforcement purpose, especially due to negative impact through the general increase in hunting pressure it promotes. Habitat and hunting management may thus be a key to favour the red-legged partridge

Experimental approach to study the alteration of MOX MIMAS fuels in an underwater storage situation

International audienceAfter irradiation in a nuclear reactor, the irradiated Mimas MOX (Mixed Oxyde) fuel assemblies are stored in a pool before reprocessing or geological disposal. This long-term storage requires considering an incidental scenario corresponding to the presence of a through defect in the zircaloy cladding, responsible for a containment breach and potential degradation of the defective rod.This defect leads to the direct interaction between the spent fuel and the pool water. The pool water is pure aerated water that can contain boric acid at a concentration of 2g/L used as neutron absorber with a pH ranging from 4 to 6.5. It is also submitted to an intense gamma radiation field (around 1 k Gray/h) due to the presence of many fuel assemblies. The temperature of the pool ranges from 40 to 80°C because of the residual power released by the radioactive decay of the fuel assemblies.These conditions are favorable to the oxidizing dissolution of the fuel under alpha and beta gamma radiolysis of water which produces hydrogen peroxide H2O2, the main oxidizing species. This alteration can lead to the release of radionuclides in solution as well as to the formation of (U,Pu)O2+x oxidized layers and to the precipitation of secondary phases such as studtite or schoepite. These phases having a density lower than that of the fuel can induce a worsening of the defect and thus impact the mechanical strength of the rods. It is therefore important to study these degradation mechanisms with the aim of recovering the rods after several years and decades of storage. In order to assess this problem, an experimental approach coupling the study of simulating materials and highly radioactive materials is developed. It aims to describe the alteration mechanisms of fuels in contact with water as well as the reaction kinetics of dissolution/precipitation. This approach consists in implementing leaching experiments on materials ranging from model compounds (U, Th)O2, to MOX Mimas fuel (U, Pu)O2 irradiated or not in reactor. The model materials are developed at the ICSM by using thorium as a redox free plutonium surrogate. Thorium has the advantage of being easily manipulated but also of having a stable +IV valence, moreover like PuO2, ThO2 crystallizes in a fluorite structure Fm-3m. Homogeneous materials (U,Th)O2 are synthesized by hydroxide route in a first step. They are used as a precursor for the synthesis of materials with a heterogeneous microstructure produced by powder mixing in order to mimic the heterogeneous character of the MOX Mimas. Moreover, after irradiation in a reactor, the chemical composition of MOX is modified by the production of fission products that are classified into four families ((I) volatile fission products, (II) metallic precipitates, (III) oxide precipitates and (IV) FPs in solid solution in the fuel [3]. Two types of FPs are also simulated in the (U,Th)O2 model materials by addition of lanthanides (category IV) and platinum group metal elements (category (II)) during the synthesis of [4].Leaching experiments for these model or plutonium-containing materials are performed using two approaches:-Under dynamic conditions at the ICSM on (U,Th)O2 simulant/surrogate materials. These multiparametric experiments allow to study the effect of fuel heterogeneity and chemistry as well as water chemistry (boric acid, [H2O2], pH) on the oxidative dissolution of the fuel.-Under static conditions in a shielded cell in the Atalante facility at Marcoule on highly radioactive materials. The gamma dose rate within an assembly will be reproduced experimentally using a 60Co source given the small amount of fuel involved for the leaching experiment.These alteration experiments will be monitored over time by analyzing the solutions chemically and radiometrically and using surface characterization tools, the main one being Raman spectroscopy. This technique allows monitoring the evolution of many key parameters such as the chemical composition of the solid/solution interface, uranium oxidation state and the nature of the precipitated phases. It is also an isotopically sensitive technique for studying oxidation processes at the atomic scale [5, 6]. All this work will improve our understanding of the mechanisms of fuel oxidation and secondary phase precipitation in order to develop mechanistic model coupling chemistry to transport of chemical species in a defective rod. It will also contribute to the analysis of data acquired on defective rods extracted from storage pools

Contrasted impacts of weather conditions in species sensitive to both survival and fecundity: A montane bird case study

Abstract There is growing evidence that the Earth's climate is undergoing profound changes that are affecting biodiversity worldwide. This gives rise to the pressing need to develop robust predictions on how species will respond in order to inform conservation strategies and allow managers to adapt mitigation measures accordingly. While predictions have begun to emerge on how species at the extremes of the so‐called slow‐fast continuum might respond to climate change, empirical studies for species for which all demographic traits contribute relatively equally to population dynamics are lacking. Yet, climate change is expected to strongly affect them throughout their entire lifecycle. We built a 21‐year integrated population model to characterize the population dynamics of the rock partridge ( Alectoris graeca ) in France, and tested the influence of nine weather covariates on demographic parameters. As predicted, both annual survival and breeding success were affected by weather covariates. Thick snow cover during winter was associated with low survival and small brood size the following breeding season. Brood size was higher with intermediate winter temperatures and snowmelt timing, positively correlated to breeding period temperature, but negatively correlated to temperature during the coldest fortnight and precipitation during the breeding period. Survival was positively correlated to winter temperature, but negatively to breeding period precipitation. Large‐scale indices indicated that cold and wet winters were associated with small brood size the following breeding season but with high survival. Expected changes of weather conditions due to climate change are likely to impact demographic traits of the rock partridge both positively and negatively depending on the traits and on the affected weather variables. Future population dynamics will thus depend on the magnitude of these different impacts. Our study illustrates the difficulty to make strong predictions about how species with a population dynamic influenced by both survival and fecundity will respond to climate change

Bioresorbable polylactic acid (PLA) and bioactive glasses (BG) composite: influence of gold coated of BG powder on mechanical properties and chemical reactivity

International audienceDue to the ageing of the population, the synthesis of biomaterials and the optimization of their physico-chemical characteristics are at the heart of many research projects in regenerative medicine. The emergence of 3D printing techniques has rapidly led to the manufacture PLA-BG compositescaffolds using the FFF (Fused Filament Fabrication) technic. However, this composite presents some problems including a lower mechanical strength than the two compounds alone, probably due to the ionic salting-out induced by the BG. This study aims to counter this phenomenon by coating the BG particles with a thin layer of gold. The 3D composite objects will then be characterized mechanically and biologically to ensure that the bioactive character of the composite is preserved

Treatment of Psychiatric Disorders and Skin-Restricted Lupus Remission

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Alteration of a Mimas MOX fuel subjected to water radiolysis: surface characterization by optical/SEM image analysis and Raman spectroscopy.

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Failure of Passive Immunity Transfer Is Not a Risk Factor for Omphalitis in Beef Calves

Omphalitis is the third most frequent disease in newborn calves after neonatal diarrhea and bovine respiratory disease (BRD), but limited data on the prevalence and risk factors are available in the literature. Failure of passive immunity transfer (FPIT) is recognized as a major risk factor for diseases and mortality in calves. However, the association between omphalitis and FPIT remains poorly described. To assess this association, 964 suckler beef calves from 22 farms were included in a longitudinal cohort study for 5 months. Each calf was examined twice (mean ages: 4.4 and 11.1 days old) to diagnose omphalitis through clinical examination and ultrasonographic evaluation (USE) if necessary. Measurements of the total solids percentage (TS-%Brix) and total protein (TP) were performed on the serum during the first visit to evaluate the calves’ passive immunity status. FPIT (fair and poor) was defined as serum %Brix < 8.1 or TP < 5.1 g/dL; among calves with omphalitis, 14% had FPIT and among calves without omphalitis 12% had FPIT. The omphalitis prevalence was 32.3% in calves without any other disease (overall prevalence of 30.9%). No statistical association between the prevalence of omphalitis and FPIT was observed. Further research is needed to identify the risk factors and promote the prevention measures for omphalitis in cow–calf systems, such as calving difficulty, hygiene of housing, and navel disinfection