Estimation de la contribution des émissions Îhiculaires à l'échappement et hors-échappement aux teneurs atmosphériques en PM10 par Positive Matrix Factorization (PMF)

The goal of this work is the development of a methodology allowing the assessment of road traffic exhaust and non-exhaust contributions (resuspension of road dusts, from brakes, tyres and road-surface-wear, from the corrosion of vehicle components...) to PM10 in an urban site. The approach used source apportionment modelling by PMF (Positive Matrix Factorization) with a chemical data set including chemical tracers. These data are obtained thanks to filter samples collected during short-time periods (4h temporal resolution). This study also includes the simultaneous sampling of chemical species on an urban background site (Grenoble-Les Frênes, France) and on a roadside site (Grenoble-Echirolles, France). This combination leads to accurate determination of traffic indicators sources. Finally, the source apportionment using PMF applied to this database gives possible contribution of sources to PM10. Results show that the road traffic source contribution to PM10 (exhaust + non-exhaust sources) was on average 34% and ranged from about 57% during the rush hours to 14% during less busy periods. Non-exhaust contribution is on average equivalent to the exhaust one.L'objectif de cette étude est de tester une méthodologie permettant de déterminer les contributions respectives aux teneurs atmosphériques en PM10 des émissions Îhiculaires à l'échappement et hors échappement (abrasion des freins, des pneus et de la route, remise en suspension des poussières de la chaussée...) dans un milieu urbain. La stratégie adoptée est d'appliquer une méthode de déconvolution des sources par un modèle statistique d'analyses multivariées (PMF, Positive Matrix Factorization) sur un jeu de données chimiques obtenues avec des filtres collectés sur des durées réduites (4h) et comprenant des traceurs spécifiques. Les prélèvements ont été réalisés simultanément sur un site de fond urbain (Grenoble-Les Frênes, France) et sur un site de proximité automobile (Grenoble-Échirolles, France). La discrimination des sources et la quantification de leur contribution par PMF sont ensuite obtenues sur la base de données établie. Les résultats montrent que les émissions Îhiculaires à l'échappement et hors échappement contribuent en moyenne à 34 % des PM10 et jusqu'à 57 % durant les heures de pointe, contre seulement 14 % durant les heures creuses. Sur la période de mesure, les émissions hors échappement sont en moyenne équivalentes aux émissions à l'échappement pour le site d'étude de proximité trafic

Perception de la hauteur et du temps dans des séquences musicales tonales (études comportementales et neuropsychologiques)

L objectif de ce travail de thèse est d étudier la perception de deux dimensions porteuses de formes de la musique occidentale tonale : la hauteur (i.e., relation harmonique entre les notes) et le temps (i.e., rythme et métrique). De nombreuses études se sont intéressées à la perception de l une ou l autre des dimensions mais peu ont étudié leur traitement conjoint. La question de leur traitement, indépendant ou interactif, ainsi que les corrélats neuronaux leur étant dédiés, sont abordés dans cette thèse. Dans un premier volet, une approche de psychologie cognitive est utilisée afin d étudier l influence du niveau de traitement et du matériel sur le traitement de la hauteur et du temps. Trois études comportementales suggèrent que le traitement indépendant ou interactif de la hauteur et du temps dépend du niveau de traitement impliqué : pour les premiers niveaux de traitement, les deux dimensions seraient indépendantes et, interagiraient à des niveaux plus tardifs d intégration de l information. Dans un deuxième volet, une approche neuropsychologique a été utilisée pour étudier les corrélats neuronaux au traitement de la hauteur et du temps. Une étude chez des patients atteints de lésions du cervelet a montré qu ils présentaient des troubles de la perception de la dimension temporelle, le traitement de la hauteur demeurant intacte. Une étude réalisée chez des auditeurs sains a permis d observer une préférence hémisphérique droite pour le traitement de la hauteur mais aucune latéralisation n a été observée pour la dimension temporelle. Les données des cinq études sont discutées dans la cadre d un modèle neuropsychologique qui propose d expliquer les différentes étapes de traitement de la hauteur et du tempsThe aim of my PhD was to study the perception of two musical dimensions : pitch (i.e., harmonic relation between tones) and time (i.e., rhythm and meter). Numerous research has been interested in the perception of pitch and time separately but only few have focused on their joint processing. The independence or interaction of pitch and time processing as well as their underlying neuronal networks involved have been studied in my PhD. In a first part, using a behavioral approach of cognitive psychology in healthy listeners, three experiments studied influence of the level of processing and the material used on the processing of pitch and time dimensions. The findings suggest that the independent or interactive processing of pitch and time depends on the level of processing: in the first levels, the two dimensions seem to be processed independently but interact at later levels of processing in integration. In a second part, using a neuropsychological approach, we analyzed neural networks implicated in the processing of pitch and time. Cerebellar patients showed to be impaired in the perception of the time dimension but not for the pitch dimension. A study, with healthy listeners, concluded that the pitch dimension would be rather processed by the right hemisphere whereas no hemispheric advantage was observed for the time dimension. The findings of the studies are discussed in a neuropsychological model to explain the different stages of the processing of pitch and timeLYON1-BU.Sciences (692662101) / SudocSudocFranceF

Chemical Characterization of PM2.5 for the Year 2013 for 5 Rural Background Sites in France

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On the Use of Organic Molecular Markers for the Apportionment of Aerosols - Insight from PMF Analysis at 3 French Urban Sites

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Chemical Characterization of PM2.5 for the Year 2013 for 5 Rural Background Sites in France

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Comparison of PM10 Sources Profiles at 15 French Sites Using a Harmonized Constrained Positive Matrix Factorization Approach

International audienceReceptor-oriented models, including positive matrix factorization (PMF) analyses, are now commonly used to elaborate and/or evaluate action plans to improve air quality. In this context, the SOURCES project has been setup to gather and investigate in a harmonized way 15 datasets of chemical compounds from PM 10 collected for PMF studies during a five-year period (2012-2016) in France. The present paper aims at giving an overview of the results obtained within this project, notably illustrating the behavior of key primary sources as well as focusing on their statistical robustness and representativeness. Overall, wood burning for residential heating as well as road transport were confirmed to be the two main primary sources strongly influencing PM 10 loadings across the country. While wood burning profiles, as well as those dominated by secondary inorganic aerosols, present a rather good homogeneity among the sites investigated, some significant variabilities were observed for primary traffic factors, illustrating the need to better characterize the diversity of the various vehicle exhaust and non-exhaust emissions. Finally, natural sources, such as sea salts (widely observed in internal mixing with anthropogenic compounds), primary biogenic aerosols and/or terrigenous particles, were also found as non-negligible PM 10 components at every investigated site

Natural History of Recurrent Alcohol‐Related Cirrhosis After Liver Transplantation: Fast and Furious

International audienceAlcohol-related liver disease (ALD) is one of the main indications for liver transplantation (LT). Severe alcohol relapse can rapidly lead to recurrent alcohol-related cirrhosis (RAC) for the graft. The aim of this study was to describe the natural history of RAC and the overall survival after LT and after an RAC diagnosis. From 1992 to 2012, 812 patients underwent primary LT for ALD in 5 French transplant centers. All patients with severe alcohol relapse and an RAC diagnosis on the graft were included. The diagnosis of cirrhosis was based on the analysis of liver biopsy or on the association of clinical, biological, radiological, and/or endoscopic features of cirrhosis. RAC was diagnosed in 57/162 patients (35.2%) with severe alcohol relapse, and 31 (54.4%) of those patients had at least 1 episode of liver decompensation. The main types of decompensation were ascites (70.9%), jaundice (58.0%), and hepatic encephalopathy (9.6%). The cumulative probability of decompensation was 23.8% at 5 years, 50.1% at 10 years, and 69.9% at 15 years after LT. During the follow-up, 36 (63.2%) patients died, the main cause of death being liver failure (61.1%). After diagnosis of cirrhosis, the survival rate was 66.3% at 1 year, 37.8% at 5 years, and 20.6% at 10 years. In conclusion, RAC is associated with a high risk of liver decompensation and a poor prognosis. Prevention of severe alcohol relapse after LT is a major goal to improve patient survival

Arabitol, mannitol, and glucose as tracers of primary biogenic organic aerosol: the influence of environmental factors on ambient air concentrations and spatial distribution over France

International audienceThe primary sugar compounds (SCs, defined as glucose, arabitol, and mannitol) are widely recognized as suitable molecular markers to characterize and apportion primary biogenic organic aerosol emission sources. This work improves our understanding of the spatial behavior and distribution of these chemical species and evidences their major effective environmental drivers. We conducted a large study focusing on the daily (24 h) PM 10 SC concentrations for 16 increasing space scale sites (local to nationwide), over at least 1 complete year. These sites are distributed in several French geographic areas of different environmental conditions. Our analyses, mainly based on the examination of the short-term evolutions of SC concentrations, clearly show distance-dependent correlations. SC concentration evo-lutions are highly synchronous at an urban city scale and remain well correlated throughout the same geographic re-Published by Copernicus Publications on behalf of the European Geosciences Union. 11014 A. Samaké et al.: Arabitol, mannitol, and glucose as tracers of primary biogenic organic aerosol gions, even if the sites are situated in different cities. However , sampling sites located in two distinct geographic areas are poorly correlated. Such a pattern indicates that the processes responsible for the evolution of the atmospheric SC concentrations present a spatial homogeneity over typical areas of at least tens of kilometers. Local phenomena, such as the resuspension of topsoil and associated microbiota, do no account for the major emissions processes of SC in urban areas not directly influenced by agricultural activities. The concentrations of SC and cellulose display remarkably synchronous temporal evolution cycles at an urban site in Greno-ble, indicating a common source ascribed to vegetation. Additionally , higher concentrations of SC at another site located in a crop field region occur during each harvest periods, indicating resuspension processes of plant materials (crop de-tritus, leaf debris) and associated microbiota for agricultural and nearby urbanized areas. Finally, ambient air temperature, relative humidity, and vegetation density constitute the main effective drivers of SC atmospheric concentrations

Importance of the PBOA fraction of PM10

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