132 research outputs found

    Study of the Eutectoid Transformation in Nodular Cast Irons in Relation to Solidification Microsegregation

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    Eutectoid transformation in cast irons may proceed in the stable or the metastable systems giving ferrite and graphite for the former and pearlite for the latter. The present work demonstrates that composition profiles across ferrite/pearlite boundaries are smooth and similar to those issued from the solidification step. No trace of long-range diffusion of substitutional solutes due to austenite decomposition could be observed. In turn, this ascertains that both stable and metastable transformations proceed with the product matrix—either ferrite opearlite—inheriting the parent austenite content in substitutional solutes. This result sustains a physical model for eutectoid transformation based on the so-called local para-equilibrium which is commonly used for describing solid-state transformation in steels

    What impacts of climate change on surface water in France by 2070? Results of the Explore2070 project in metropolitan France and overseas departments

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    International audienceLes questions relatives à la disponibilité et à la gestion de l'eau concentreront l'essentiel des mesures d'adaptation qui seront prises dans les décennies à venir pour faire face aux conséquences des changements climatiques. Ces mesures devront également prendre en compte les évolutions socio-économiques, en termes de démographie, d'aménagement du territoire et de politiques publiques (agriculture, énergie, transports, etc.). Il est dès lors primordial pour les décideurs et gestionnaires de quantifier les évolutions socio-économiques possibles, ainsi que le devenir de la ressource en eau et de sa variabilité temporelle et spatiale. C'est dans ce contexte que le projet Explore2070 avait pour objectif d'évaluer les impacts possibles des changements climatiques et socio-économiques futurs sur les grandes masses d'eau (surface, souterrain, littoral) et la biodiversité, en France métropolitaine et sur les départements d'Outre-mer (Guadeloupe, Guyane, Martinique et Réunion). Piloté par le Ministère de l'Ecologie (MEDDTL), ce projet a rassemblé de nombreux bureaux d'études et instituts de recherche pour dresser un panorama général des évolutions à attendre à l'horizon 2070. Par son ampleur et la variété de ses objectifs, ce projet doit permettre de répondre à de nombreuses questions des gestionnaires et de mieux apprécier les enjeux de ces évolutions. Dans la suite, nous présentons les travaux réalisés spécifiquement sur la quantification des évolutions des eaux de surface. Nous détaillerons dans ce qui suit la démarche générale de modélisation proposée, la nature des résultats obtenus, ainsi que la façon dont les incertitudes ont été quantifiées. Ce dernier point est indispensable pour aider à la prise de décision dans un avenir incertain. / Water availability and water management will be the focus of most of the adaptation measures that will be taken in the next decades to face the consequences of climate change. These measures will have to account for the socio-economic evolutions, in terms of population size, town and country planning, as well as public policies (agriculture, energy, transports, etc.). It is therefore essential for decision makers and managers to be able to quantify the possible socio-economic evolutions together with the evolution of water resources and their temporal and spatial variability. In this context, the Explore2070 project aimed at evaluating the possible impacts of future climate and socio-economic changes on water bodies (surface water, groundwater and coastal water) and biodiversity, in metropolitan France and overseas departments (Guadeloupe, Martinique, French Guyana, and Réunion Island). The project was managed by the French Ministry of Ecology (MEDDTL) and gathered several consultancies and research institutes to establish a general overview of the expected evolutions by 2070. Through both the extent and the variety of the project’s objectives, Explore2070 will provide answers to many questions raised by managers and better evaluate the stakes related to these evolutions. In the following, we present the work done specifically to quantify the evolution of surface water. The general modelling approach, the type of results and the way uncertainties were quantified are detailed. Uncertainty quantification is essential to help decision making in an uncertain future

    Phases and properties of quark matter

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    I review recent developments in finite temperature lattice QCD which are useful for the study of heavy-ion collisions. I pay particular attention to studies of the equation of state and the light they throw on conformal symmetry and the large N_c limit, and to the structure of the phase diagram for N_f=2+1.Comment: Plenary talk at Quark Matter 2008, Jaipur, India (8 pages, 5 figures

    Vida Verde. Barcelona

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    International audienceWe demonstrate, on a scramjet combustion problem, a constrained probabilistic learning approach that augments physics-based datasets with realizations that adhere to underlying constraints and scatter. The constraints are captured and delineated through diffusion maps, while the scatter is captured and sampled through a projected stochastic differential equation. The objective function and constraints of the optimization problem are then efficiently framed as non-parametric conditional expectations. Different spatial resolutions of a large-eddy simulation filter are used to explore the robustness of the model to the training dataset and to gain insight into the significance of spatial resolution on optimal design

    Magnetic properties changes of MnAs thin films irradiated with highly charged ions

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    We present the first investigation on the effect of highly charged ion bombardment on a manganese arsenide thin film. The MnAs films, 150 nm thick, are irradiated with 90 keV Ne9+^{9+} ions with a dose varying from 1.6×10121.6\times10^{12} to 1.6×10151.6\times10^{15} ions/cm2^2. The structural and magnetic properties of the film after irradiation are investigated using different techniques, namely, X-ray diffraction, magneto-optic Kerr effect and magnetic force microscope. Preliminary results are presented. From the study of the lattice spacing, we measure a change on the film structure that depends on the received dose, similarly to previous studies with other materials. Investigations on the surface show a strong modification of its magnetic properties

    A reaction norm model for genomic selection using high-dimensional genomic and environmental data

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    In most agricultural crops the effects of genes on traits are modulated by environmental conditions, leading to genetic by environmental interaction (G × E). Modern genotyping technologies allow characterizing genomes in great detail and modern information systems can generate large volumes of environmental data. In principle, G × E can be accounted for using interactions between markers and environmental covariates (ECs). However, when genotypic and environmental information is high dimensional, modeling all possible interactions explicitly becomes infeasible. In this article we show how to model interactions between high-dimensional sets of markers and ECs using covariance functions. The model presented here consists of (random) reaction norm where the genetic and environmental gradients are described as linear functions of markers and of ECs, respectively. We assessed the proposed method using data from Arvalis, consisting of 139 wheat lines genotyped with 2,395 SNPs and evaluated for grain yield over 8 years and various locations within northern France. A total of 68 ECs, defined based on five phases of the phenology of the crop, were used in the analysis. Interaction terms accounted for a sizable proportion (16 %) of the within-environment yield variance, and the prediction accuracy of models including interaction terms was substantially higher (17–34 %) than that of models based on main effects only. Breeding for target environmental conditions has become a central priority of most breeding programs. Methods, like the one presented here, that can capitalize upon the wealth of genomic and environmental information available, will become increasingly important

    Population genomic screening of all young adults in a health-care system: A cost-effectiveness analysis

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    Purpose:To consider the impact and cost-effectiveness of offering preventive population genomic screening to all young adults in a single-payer health-care system.Methods:We modeled screening of 2,688,192 individuals, all adults aged 18–25 years in Australia, for pathogenic variants in BRCA1/BRCA2/MLH1/MSH2 genes, and carrier screening for cystic fibrosis (CF), spinal muscular atrophy (SMA), and fragile X syndrome (FXS), at 71% testing uptake using per-test costs ranging from AUD200to200 to 1200 (~USD140to140 to 850). Investment costs included genetic counseling, surveillance, and interventions (reimbursed only) for at-risk individuals/couples. Cost-effectiveness was defined below AUD50,000/DALY(disabilityadjustedlifeyear)prevented,usinganincrementalcosteffectivenessratio(ICER),comparedwithcurrenttargetedtesting.Outcomeswerecancerincidence/mortality,diseasecases,andtreatmentcostsreduced.Results:Populationscreeningwouldreducevariantattributablecancersby28.850,000/DALY (disability-adjusted life year) prevented, using an incremental cost-effectiveness ratio (ICER), compared with current targeted testing. Outcomes were cancer incidence/mortality, disease cases, and treatment costs reduced.Results:Population screening would reduce variant-attributable cancers by 28.8%, cancer deaths by 31.2%, and CF/SMA/FXS cases by 24.8%, compared with targeted testing. Assuming AUD400 per test, investment required would be between 4 and 5 times higher than current expenditure. However, screening would lead to substantial savings in medical costs and DALYs prevented, at a highly cost-effective ICER of AUD4038/DALY.AtAUD4038/DALY. At AUD200 per test, screening would approach cost-saving for the health system (ICER = AUD$22/DALY).Conclusion:Preventive genomic screening in early adulthood would be highly cost-effective in a single-payer health-care system, but ethical issues must be considered

    The Medical Genome Reference Bank contains whole genome and phenotype data of 2570 healthy elderly

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    Population health research is increasingly focused on the genetic determinants of healthy ageing, but there is no public resource of whole genome sequences and phenotype data from healthy elderly individuals. Here we describe the first release of the Medical Genome Reference Bank (MGRB), comprising whole genome sequence and phenotype of 2570 elderly Australians depleted for cancer, cardiovascular disease, and dementia. We analyse the MGRB for single-nucleotide, indel and structural variation in the nuclear and mitochondrial genomes. MGRB individuals have fewer disease-associated common and rare germline variants, relative to both cancer cases and the gnomAD and UK Biobank cohorts, consistent with risk depletion. Age-related somatic changes are correlated with grip strength in men, suggesting blood-derived whole genomes may also provide a biologic measure of age-related functional deterioration. The MGRB provides a broadly applicable reference cohort for clinical genetics and genomic association studies, and for understanding the genetics of healthy ageing
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